Abstract:
Thirst and antidiuretic hormone secretion occur during hyperthermia or hypertonicity to preserve body hydration. These vital responses are triggered when hypothalamic osmoregulatory neurons become depolarized by ion channels encoded by an unknown product of the transient receptor potential vanilloid-1 gene (Trpv1). Here, we show that rodent osmoregulatory neurons express a transcript of Trpv1 that mediates the selective translation of a TRPV1 variant that lacks a significant portion of the channel's amino terminus (DeltaN-TRPV1). The mRNA transcript encoding this variant (Trpv1dn) is widely expressed in the brains of osmoregulating vertebrates, including the human hypothalamus. Transfection of Trpv1dn into heterologous cells induced the expression of ion channels that could be activated by either hypertonicity or by heating in the physiological range. Moreover, expression of Trpv1dn rescued the osmosensory and thermosensory responses of single hypothalamic neurons obtained from Trpv1 knockout mice. DeltaN-TRPV1 is therefore a co-detector of core body temperature and fluid tonicity.

Abstract:
We present the case of a 43-year-old man with acute visual loss due to an optic chiasm cavernoma. Our clinical and imaging findings quickly led us to this diagnosis. As a clinical improvement spontaneously occurred soon after the initial diagnosis, we decided not to perform any surgical treatment. The visual evolution was satisfactory and, to date after a 36-months follow-up, no clinical worsening has been reported. We present this clinical case regarding our approach, primarily a close follow-up, as well as a review of the literature.

Abstract:
BACKGROUND: Despite a growing use of rituximab (RTX) in neuromyelitis optica (NMO), data are lacking in patients with refractory NMO (RNMO), defined as cases with at least one relapse during immunosuppressive therapy. OBJECTIVE: The purpose of this study was to assess RTX as a maintenance therapy in RNMO. METHODS: Out of a total of 305 NMO cases from a population-based cohort, 21 RNMO patients received RTX during a mean follow-up period of 31 months. RESULTS: After RTX, 11 patients (52.3%) were relapse free, meaning that 47.7% were refractory to RTX. The mean annualized relapse rate decreased from 1.3 to 0.4 (p<0.001) and median EDSS from 5 to 3 (p=0.02). Body mass index (BMI) was predictive of EDSS worsening. CONCLUSIONS: RTX is an effective and well-tolerated treatment in RNMO. BMI could be a predictive factor for efficacy.

Abstract:
OBJECTIVES: To explore long-term effects of treatment and prognostic relevance of variables assessed at baseline and during the European secondary progressive multiple sclerosis (SPMS) trial of interferon beta 1b (IFNB-1b). METHODS: We assessed 362 patients (60% female; median age 41 years; Expanded Disability Status Scale (EDSS): 5.5; 51% randomized to IFNB-1b) for their EDSS and treatment history after 10 years. Non-parametric analysis of covariance (ANCOVA) and multivariate linear regression models were applied. RESULTS: Median EDSS was 6.0 at the end of the randomized controlled trial (RCT), in the IFNB-1b and placebo groups, and 7.0 in long-term follow-up patients (those receiving IFNB-1b in the RCT were 6.5 and those receiving placebo in the RCT were 7.0; p = 0.086). 24 patients (6.6%) were deceased. The EDSS at baseline and the EDSS change during the RCT were the most important predictors of the EDSS 10 years later (partial R2: 0.47). The ability to predict changes in EDSS 10 years after the RCT was limited (R2: 0.12). Magnetic resonance imaging (MRI) measures remained in the predictive models, but explained < 5% of the variability. CONCLUSIONS: The results from this analysis did not provide convincing evidence to support a favorable long-term outcome in those patients allocated IFNB-1b during the RCT, in our SPMS cohort. The progressive stage of the disease remains largely unpredictable by clinical and conventional MRI measures, so better prognostic markers are needed.

Abstract:
Recent technological developments, such as single unit recordings coupled to optogenetic approaches, have provided unprecedented knowledge about the precise neuronal circuits contributing to the expression and recovery of conditioned fear behavior. These data have provided an understanding of the contributions of distinct brain regions such as the amygdala, prefrontal cortex, hippocampus, and periaqueductal gray matter to the control of conditioned fear behavior. Notably, the precise manipulation and identification of specific cell types by optogenetic techniques have provided novel avenues to establish causal links between changes in neuronal activity that develop in dedicated neuronal structures and the short and long-lasting expression of conditioned fear memories. In this review, we provide an update on the key neuronal circuits and cell types mediating conditioned fear expression and recovery and how these new discoveries might refine therapeutic approaches for psychiatric conditions such as anxiety disorders and posttraumatic stress disorder.

Abstract:
BACKGROUND: The independent prognostic value of cerebrospinal fluid analysis in multiple sclerosis is not established. OBJECTIVE: To determine the prognostic value of intrathecal synthesis in a cohort of patients with relapsing-onset MS taking into consideration demographic and imaging parameters. METHODS: In this prospective cohort study conducted from 1993 to 2013, we analyzed the time to confirmed disability (persistent above 6 months) and irreversible disability (persistent for the entire disease course) of two disability milestones, Expanded Disability Status Scale score >/= 4 or 6, and the time to secondary progressive onset in 579 patients with relapsing-onset multiple sclerosis. Demographic parameters (age at onset, gender) and imaging parameters (periventricular lesions) were included in the Cox models. RESULTS: 447 patients (77.2%) had intrathecal synthesis (oligoclonal bands and/or increased immunoglobulin G index value). No statistically significant relation was found between intrathecal synthesis and the time to reach each disability milestone or secondary progressive onset. An age older than 40 years and more than 3 periventricular lesions predicted a worse prognosis. CONCLUSIONS: Cerebrospinal fluid analysis did not predict the time to disability milestones in relapsing-onset multiple sclerosis independently of age and imaging data.

Abstract:
Activation of N-methyl-d-aspartate (NMDA) receptors is critical for hypersensitivity in chronic neuropathic pain. Since astroglia can regulate NMDA receptor activation by releasing the NMDA receptor co-agonist d-serine, we investigated the role of NMDA receptor and d-serine in neuropathic chronic pain. Male Wistar rats underwent right L5-L6 spinal nerve ligation or sham surgery and were tested for mechanical allodynia and hyperalgesia after 14 days. Acute intrathecal administration of the NMDA receptor antagonist AP-5 as well as chronic administration of the glia metabolism inhibitor fluoroacetate significantly reduced mechanical allodynia in neuropathic rats. The effect of fluoroacetate was reversed by acutely administered intrathecal d-serine. Degrading d-serine using acute intrathecal administration of d-aminoacid oxidase also reduced pain symptoms. Immunocytochemistry showed that about 70% of serine racemase, the synthesizing enzyme of d-serine, was expressed in astrocyte processes in the superficial laminae of L5 dorsal horn. Serine racemase expression was upregulated in astrocyte processes in neuropathic rats compared to sham rats. These results show that neuropathic pain depends upon glial d-serine that co-activates spinal NMDA receptors.

Abstract:
Isolated tumefactive demyelinating lesion (TDL) is a rare disease and a challenging entity especially for the differential diagnosis, biopsy indications, and therapeutic decisions. Long-term evolution is not well known. The objective of the study is to describe clinical and MRI characteristics and long-term follow-up of patients with isolated TDL. We performed a retrospective study including patients (1) with one TDL radiologically defined by a >/=20 mm FLAIR hyperintensity involving the white matter associated with T1 hypointensity that enhanced after gadolinium injection and (2) without any other MS lesion on the first MRI. Tumor, abscess, or other inflammatory diseases (ADEM, Balo's concentric sclerosis, systemic disease) were excluded. Sixteen patients (11 females/5 males) were included. The mean age of onset was 35.7 years (range 20-65). MRI disclosed supratentorial lesions with a mean size of 39.4 mm and usually mild edema/mass effect. Peripheral (mainly open-ring pattern) and central (mainly heterogeneous) enhancement were respectively seen in 9/16 and 11/16 patients. CSF study (n = 15) found oligoclonal bands (OCB) in seven. A cerebral biopsy was performed in 11 cases showing acute inflammatory demyelination. Thirteen patients were treated by pulse steroids with marked improvement in ten. At last clinical follow-up (mean 65.8 months, range 6-181), diagnosis was MS in 5 (31 %), isolated TDL in 10 (63 %) and one patient had a second TDL (6 %). Isolated tumefactive demyelinating lesions are a rare diagnostic entity. After a mean follow-up of 5 years, almost one-third became MS whereas most of the patients had no further event.

Abstract:
Our aim was to evaluate the association between magnetisation transfer imaging (MTI) parameters measured 30 to 45 days after a cerebrovascular insult and post-stroke functional outcome at the same time. MTI offers the opportunity to depict subtle microstructural changes in infarcted areas. The clinical significance of the heterogeneity of brain damage within ischaemic stroke lesions is unknown. We prospectively included 58 patients with acute middle cerebral artery stroke. Diffusion-weighted imaging was performed within 12 hours after onset and the final infarct was documented by MRI with fluid-attenuated inversion recovery (FLAIR) and MTI at 30 to 45 days follow-up. We evaluated the association between MTI histogram parameters and the clinical outcome assessed by dichotomised (threshold >2) modified rankin scale (mRS) using multivariable logistic regression models adjusted on baseline characteristics. In multivariable analyses, stroke outcome was mostly driven by initial National Institutes of Health Stroke Scale (odds ratio [OR]=1.23; 95% confidence interval [CI]=1.07-1.41; p<0.01) while after adjustment of initial stroke severity magnetisation transfer ratio peak position was the only MRI parameter associated with functional status at 30 to 45 days post-stroke (OR=0.86; 95% CI=0.75-0.98; p=0.02); lower peak position values associated with higher mRS. Conversely, stroke volume measured on FLAIR sequence was not associated with stroke prognosis (p=0.87). The intensity of microstructural changes within the infarct core measured at 30 to 45 days follow-up is independently associated with the functional status evaluated at the same time. MTI and related parameters could be used as surrogate markers of treatment response in stroke clinical trials.

Abstract:
Multiple sclerosis (MS) is most generally considered as a severe disease with high physical and mental risks of disability. Since the end of the 1990s, several high cost long-term disease-modifying treatments provided some clinical efficiency. However, patient's follow-up was needed for the detection and the assessment of their side-effects. The 'Observatoire francais de la sclerose en plaques' (OFSEP) project aims to improve the clinical, biological and imaging systematic longitudinal follow-up of patients. It should increase the quality, efficiency and safety of patients' care, with a unique opportunity of large scale, about 41,000 patients followed in 62 French centers using the European Database for Multiple Sclerosis (EDMUS) software. OFSEP is divided into three working groups (clinical, biological and imaging). The imaging working group defines standards for routine MRI follow-up in the whole cohort and contains three subgroups: acquisition, workflow, and data processing. A common and feasible brain and spinal cord acquisition protocol has been defined by the acquisition group, and accepted by the OFSEP steering and scientific committees. This protocol can be implemented in all French MRI centers. The major MRI manufacturers have agreed to provide the dedicated collection of sequences as an 'OFSEP box' with every software upgrade or new MRI machine. The new OFSEP protocol will provide a unique opportunity to study a population-based collection of data from people with MS.

Abstract:
In the brain, astrocytes occupy a key position between vessels and synapses. Among their numerous functions, these glial cells are key partners of neurons during synaptic transmission. Astrocytes detect transmitter release through receptors and transporters at the level of their processes, which are in close proximity to the tow neuronal elements of synapses. In response to transmitter-mediated activation, glial cells in turn regulate synaptic transmission and neuronal excitability. This process has been reported to involve several glial receptors. One of the best known of such receptors is the metabotropic glutamatergic receptor subtype 5 (mGluR5). In the present review we will discuss the implication of mGluR5s as detectors of synaptic transmission. In particular, we will discuss how the functional properties and localization of these receptors permit the detection of the synaptic signal in a defined temporal window and a given spatial area around the synapse. Furthermore, we will review the impact of their activation on synaptic transmission.

Abstract:
We report a young man with a history of deep coma secondary to an extensive superior sagittal sinus thrombosis despite full systemic anticoagulation. Endovascular treatment combining a 5 Max ACE reperfusion catheter (Penumbra) and Solitaire (Covidien) retrieval device permitted revascularization of the superior sagittal sinus with restoration of anterograde venous flow. This treatment led to the disappearance of cytotoxic edema on MRI and to a neurological improvement with a modified Rankin scale score of 2 after two months. Our experience shows that this technique provides a useful and safe tool after failure of anticoagulation in cerebral venous sinus thrombosis.

Abstract:
BACKGROUND AND PURPOSE: In multiple sclerosis, gadolinium enhancement is used to classify lesions as active. Regarding the need for a standardized and accurate method for detection of multiple sclerosis activity, we compared 2D-spin-echo with 3D-gradient-echo T1WI for the detection of gadolinium-enhancing MS lesions. MATERIALS AND METHODS: Fifty-eight patients with MS were prospectively imaged at 3T by using both 2D-spin-echo and 3D-gradient recalled-echo T1WI in random order after the injection of gadolinium. Blinded and independent evaluation was performed by a junior and a senior reader to count gadolinium-enhancing lesions and to characterize their location, size, pattern of enhancement, and the relative contrast between enhancing lesions and the adjacent white matter. Finally, the SNR and relative contrast of gadolinium-enhancing lesions were computed for both sequences by using simulations. RESULTS: Significantly more gadolinium-enhancing lesions were reported on 3D-gradient recalled-echo than on 2D-spin-echo (n = 59 versus n = 30 for the junior reader, P = .021; n = 77 versus n = 61 for the senior reader, P = .017). The difference between the 2 readers was significant on 2D-spin-echo (P = .044), for which images were less reproducible (kappa = 0.51) than for 3D-gradient recalled-echo (kappa = 0.65). Further comparisons showed that there were statistically more small lesions (<5 mm) on 3D-gradient recalled-echo than on 2D-spin-echo (P = .04), while other features were similar. Theoretic results from simulations predicted SNR and lesion contrast for 3D-gradient recalled-echo to be better than for 2D-spin-echo for visualization of small enhancing lesions and were, therefore, consistent with clinical observations. CONCLUSIONS: At 3T, 3D-gradient recalled-echo provides a higher detection rate of gadolinium-enhancing lesions, especially those with smaller size, with a better reproducibility; this finding suggests using 3D-gradient recalled-echo to detect MS activity, with potential impact in initiation, monitoring, and optimization of therapy.

Abstract:
The mechanisms by which dietary salt promotes hypertension are unknown. Previous work established that plasma [Na(+)] and osmolality rise in proportion with salt intake and thus promote release of vasopressin (VP) from the neurohypophysis. Although high levels of circulating VP can increase blood pressure, this effect is normally prevented by a potent GABAergic inhibition of VP neurons by aortic baroreceptors. Here we show that chronic high salt intake impairs baroreceptor inhibition of rat VP neurons through a brain-derived neurotrophic factor (BDNF)-dependent activation of TrkB receptors and downregulation of KCC2 expression, which prevents inhibitory GABAergic signaling. We show that high salt intake increases the spontaneous firing rate of VP neurons in vivo and that circulating VP contributes significantly to the elevation of arterial pressure under these conditions. These results provide the first demonstration that dietary salt can affect blood pressure through neurotrophin-induced plasticity in a central homeostatic circuit.

Abstract:
Control of the glutamate time course in the synapse is crucial for excitatory transmission. This process is mainly ensured by astrocytic transporters, high expression of which is essential to compensate for their slow transport cycle. Although molecular mechanisms regulating transporter intracellular trafficking have been identified, the relationship between surface transporter dynamics and synaptic function remains unexplored. We found that GLT-1 transporters were highly mobile on rat astrocytes. Surface diffusion of GLT-1 was sensitive to neuronal and glial activities and was strongly reduced in the vicinity of glutamatergic synapses, favoring transporter retention. Notably, glutamate uncaging at synaptic sites increased GLT-1 diffusion, displacing transporters away from this compartment. Functionally, impairing GLT-1 membrane diffusion through cross-linking in vitro and in vivo slowed the kinetics of excitatory postsynaptic currents, indicative of a prolonged time course of synaptic glutamate. These data provide, to the best of our knowledge, the first evidence for a physiological role of GLT-1 surface diffusion in shaping synaptic transmission.

Abstract:
Inherited white matter diseases are rare and heterogeneous disorders usually encountered in infancy. Adult-onset forms are increasingly recognized. Our objectives were to determine relative frequencies of genetic leukoencephalopathies in a cohort of adult-onset patients and to evaluate the effectiveness of a systematic diagnostic approach. Inclusion criteria of this retrospective study were: (i) symmetrical involvement of white matter on the first available brain MRI; (ii) age of onset above 16 years. Patients with acquired diseases were excluded. Magnetic resonance imaging analysis identified three groups (vascular, cavitary and non-vascular/non-cavitary) in which distinct genetic and/or biochemical testing were realized. One hundred and fifty-four patients (male/female = 60/94) with adult-onset leukoencephalopathies were identified. Mean age of onset was 38.6 years. In the vascular group, 41/55 patients (75%) finally had a diagnosis [including CADASIL (cerebral autosomal-dominant arteriopathy with subcortical infarcts and leukoencephalopathy, n = 32) and COL4A1 mutation, n = 7]. In the cavitary group, 13/17 (76%) patients had a diagnosis of EIF2B-related disorder. In the third group (n = 82), a systematic biological screening allowed a diagnosis in 23 patients (28%) and oriented direct genetic screening identified 21 additional diseases (25.6%). Adult-onset genetic leukoencephalopathies are a rare but probably underestimated entity. Our study confirms the use of a magnetic resonance imaging-based classification with a final diagnosis rate of 64% (98/154) cases.

Abstract:
Hypothalamic peptidergic neurons using kisspeptin (KP) and its co-transmitters for communication are critically involved in the regulation of mammalian reproduction and puberty. This article provides an overview of neuropeptides present in KP neurons, with a focus on the human species. Immunohistochemical studies reveal that large subsets of human KP neurons synthesize neurokinin B, as also shown in laboratory animals. In contrast, dynorphin described in KP neurons of rodents and sheep is found rarely in KP cells of human males and postmenopausal females. Similarly, galanin is detectable in mouse, but not human, KP cells, whereas substance P, cocaine- and amphetamine-regulated transcript and proenkephalin-derived opioids are expressed in varying subsets of KP neurons in humans, but not reported in ARC of other species. Human KP neurons do not contain neurotensin, cholecystokinin, proopiomelanocortin-derivatives, agouti-related protein, neuropeptide Y, somatostatin or tyrosine hydroxylase (dopamine). These data identify the possible co-transmitters of human KP cells. Neurochemical properties distinct from those of laboratory species indicate that humans use considerably different neurotransmitter mechanisms to regulate fertility.

Abstract:
BACKGROUND: Recent studies in multiple sclerosis (MS) showed longer survival times from clinical onset than older hospital-based series. However estimated median time ranges widely, from 24 to 45 years, which makes huge difference for patients as this neurological disease mainly starts around age 20 to 40. Precise and up-to-date reference data about mortality in MS are crucial for patients and neurologists, but unavailable yet in France. OBJECTIVES: Estimate survival in MS patients and compare mortality with that of the French general population. METHODS: We conducted a multicenter observational study involving clinical longitudinal data from 30,413 eligible patients, linked to the national deaths register. Inclusion criteria were definite MS diagnosis and clinical onset prior to January, 1st 2009 in order to get a minimum of 1-year disease duration. RESULTS: After removing between-center duplicates and applying inclusion criteria, the final population comprised 27,603 MS patients (F/M sex ratio 2.5, mean age at onset 33.0 years, 85.5% relapsing onset). During the follow-up period (mean 15.2 +/- 10.3 years), 1569 deaths (5.7%) were identified; half related to MS. Death rates were significantly higher in men, patients with later clinical onset, and in progressive MS. Overall excess mortality compared with the general population was moderate (Standardized Mortality Ratio 1.48, 95% confidence interval [1.41-1.55]), but increased considerably after 20 years of disease (2.20 [2.10-2.31]). CONCLUSIONS: This study revealed a moderate decrease in life expectancy in MS patients, and showed that the risk of dying is strongly correlated to disease duration and disability, highlighting the need for early actions that can slow disability progression.

Abstract:
BACKGROUND: Depressive mood and other emotional symptoms are common in multiple sclerosis (MS). The patient-reported outcome version of the 'Echelle d'Humeur Depressive' (EHD-PRO) aims to differentiate between two dimensions of depressive mood in people living with MS (PwMS). OBJECTIVES: First, to compare EHD-PRO assessment and its two dimensions, lack of emotional control and emotional blunting, between a large sample of healthy controls (HCs) and two samples of PwMS, relapsing-remitting MS (RRMS) and primary progressive MS (PPMS); and second, to analyse the relationships between EHD-PRO scores with neurological disability, cognitive function, fatigue and health-related quality of life (HR-QOL). RESULTS: Regardless of their phenotype, PwMS had significantly higher EHD-PRO scores than HCs. EHD-PRO scores did not differ between the two MS groups. EHD-PRO scores did not correlate with disability and fatigue scores, disease duration or cognitive z scores. In RRMS, the lack of emotional control was independently associated with a decrease in HR-QOL. CONCLUSION: The EHD-PRO is able to easily detect depressive mood and to differentiate between two clinical dimensions, emotional blunting and lack of emotional control. The scale is sensitive and seems robust to confounding factors. Lack of emotional control seems to contribute significantly to altered HR-QOL in RRMS.

Abstract:
BACKGROUND: Radiotherapy is one of the most important treatments of primary and metastatic brain tumors. Unfortunately, it can involve moderate to severe complications among which leukoencephalopathy is very frequent and implies cognitive deficits such as memory, attention and executive dysfunctions. However, the incidence of this complication is not well established and the risk factors and process are poorly understood. The main objective of the study is to improve knowledge on radio-induced leukoencephalopathy based on pluridisciplinar approaches combining cognitive, biologic, imagery and dosimetric investigations. METHOD/DESIGN: The EpiBrainRad study is a prospective cohort study including newly diagnosed high grade gliomas patients treated by radiotherapy and concomitant-adjuvant temozolomide chemotherapy. Patients are included between their surgery and first day of radio-chemotherapy, and the follow-up lasts for 3 years after treatment. Cognitive functioning assessments, specific blood biomarkers measures and magnetic resonance imagery are performed at different moment during the follow-up, and a specific dosimetric assessment of organs involved in the beam fields is performed. Firstly, leukoencephalopathy incidence rate will be estimated in this population. Secondly, correlations between cognitive impairments and dosimetry, biomarkers ranges and anomalies on imagery will be analyzed in order to better understand the onset and evolution of cognitive decrement associated with radiotherapy. Furthermore, a new cognitive test, quickly and easily performed, will be studied to determine its sensibility to detect leukoencephalopathy decrement. DISCUSSION: With an original multidisciplinary approach, the EpiBrainRad study aims to improve knowledge on radio-induced leukoencephalopathy in order to improve its early diagnosis and prevention. The main challenge is to preserve quality-of-life after cancer treatments which imply to study the incidence of radiation-induced complications and their associated risk factors. TRIAL REGISTRATION: NCT02544178.

Abstract:
OBJECTIVE: The aim of this work is to study the relationship between information processing speed (IPS) impairment and motor testing that reflects cerebellar function in persons with multiple sclerosis (PwMS). METHODS: 60 persons with relapsing-remitting multiple sclerosis with a mean disease duration of 4.2 +/- 4 years were studied cross-sectionally. Motor cerebellar functioning was studied using the Nine-Hole Peg Test (NHPT) and the Kurtzke Functional Status Scales, and several cognitive domains were evaluated (IPS, working memory, episodic memory, attention, executive function). Correlations between the global NHPT score and neuropsychological test scores or impairment in each cognitive domain were studied using univariate and multivariate analyses. RESULTS: The NHPT and a test of IPS significantly differentiated PwMS with and without cerebellar impairment. The NHPT total score was correlated with measures of IPS. Multivariate analyses showed a correlation between the NHPT and measures of IPS, but not between the NHPT and other neuropsychological tests that did not have a speed component. CONCLUSION: In this sample of PwMS, motor cerebellar impairment assessed by the NHPT was correlated with IPS impairment.

Abstract:
Astrocytes are being increasingly recognized as crucial contributors to neuronal function at synapses, axons, and somas. Reliable methods that can provide insight into astrocyte proteins at the neuron-astrocyte functional interface are highly desirable. Here, we conducted a mass spectrometry analysis of Percoll gradient-isolated gliosomes, a viable preparation of glial subcellular particles often used to study mechanisms of astrocytic transmitter uptake and release and their regulation. Gliosomes were compared with synaptosomes, a preparation containing the neurotransmitter release machinery, and, accordingly, synaptosomes were enriched for proteins involved in synaptic vesicle-mediated transport. Interestingly, gliosome preparations were found to be enriched for different classes of known astrocyte proteins, such as VAMP3 (involved in astrocyte exocytosis), Ezrin (perisynaptic astrocyte cytoskeletal protein), and Basigin (astrocyte membrane glycoprotein), as well as for G-protein-mediated signaling proteins. Mass spectrometry data are available via ProteomeXchange with the identifier PXD001375. Together, these data provide the first detailed description of the gliosome proteome and show that gliosomes can be a useful preparation to study glial membrane proteins and associated processes.

Abstract:
Intracranial arteriovenous malformations (AVM) are rare lesions that are often discovered fortuitously. They should be identified on CT scan and MRI before resorting to angiography; the latter is used to prepare the treatment. This article describes the various types of subpial or dural AVM and the specific characteristics that enable their differentiation with non-invasive imaging. The factors that determine the severity of these lesions, whether discovered before or after a haemorrhage, are described, as well as prognostic indicators.

Abstract:
Hypersensitivity in response to sensory stimuli and neocortical hyperexcitability are prominent features of Fragile X Syndrome (FXS) and autism spectrum disorders, but little is known about the dendritic mechanisms underlying these phenomena. We found that the primary somatosensory neocortex (S1) was hyperexcited in response to tactile sensory stimulation in Fmr1-/y mice. This correlated with neuronal and dendritic hyperexcitability of S1 pyramidal neurons, which affect all major aspects of neuronal computation, from the integration of synaptic input to the generation of action potential output. Using dendritic electrophysiological recordings, calcium imaging, pharmacology, biochemistry and a computer model, we found that this defect was, at least in part, attributable to the reduction and dysfunction of dendritic h- and BKCa channels. We pharmacologically rescued several core hyperexcitability phenomena by targeting BKCa channels. Our results provide strong evidence pointing to the utility of BKCa channel openers for the treatment of the sensory hypersensitivity aspects of FXS.

Abstract:
The concept of the tripartite synapse reflects the important role that astrocytic processes are thought to play in the function and regulation of neuronal synapses in the mammalian nervous system. However, many basic aspects regarding the dynamic interplay between pre- and postsynaptic neuronal structures and their astrocytic partners remain to be explored. A major experimental hurdle has been the small physical size of the relevant glial and synaptic structures, leaving them largely out of reach for conventional light microscopic approaches such as confocal and two-photon microscopy. Hence, most of what we know about the organization of the tripartite synapse is based on electron microscopy, which does not lend itself to investigating dynamic events and which cannot be carried out in parallel with functional assays. The development and application of superresolution microscopy for neuron-glia research is opening up exciting experimental opportunities in this regard. In this paper, we provide a basic explanation of the theory and operation of stimulated emission depletion (STED) microscopy, outlining the potential of this recent superresolution imaging modality for advancing our understanding of the morpho-functional interactions between astrocytes and neurons that regulate synaptic physiology.

Abstract:
N-methyl D-aspartate receptors (NMDARs) exist in different forms owing to multiple combinations of subunits that can assemble into a functional receptor. In addition, they are located not only at synapses but also at extrasynaptic sites. There has been intense speculation over the past decade about whether specific NMDAR subtypes and/or locations are responsible for inducing synaptic plasticity and excitotoxicity. Here, we review the latest findings on the organization, subunit composition and endogenous control of NMDARs at extrasynaptic sites and consider their putative functions. Because astrocytes are capable of controlling NMDARs through the release of gliotransmitters, we also discuss the role of the glial environment in regulating the activity of these receptors.

Abstract:
BACKGROUND AND PURPOSE: Alberta Stroke Program Early Computed Tomographic Score (ASPECTS) has been used to estimate diffusion-weighted imaging (DWI) lesion volume in acute stroke. We aimed to assess correlations of DWI-ASPECTS with lesion volume in different middle cerebral artery (MCA) subregions and reproduce existing ASPECTS thresholds of a malignant profile defined by lesion volume >/=100 mL. METHODS: We analyzed data of patients with MCA stroke from a prospective observational study of DWI and fluid-attenuated inversion recovery in acute stroke. DWI-ASPECTS and lesion volume were calculated. The population was divided into subgroups based on lesion localization (superficial MCA territory, deep MCA territory, or both). Correlation of ASPECTS and infarct volume was calculated, and receiver-operating characteristics curve analysis was performed to identify the optimal ASPECTS threshold for >/=100-mL lesion volume. RESULTS: A total of 496 patients were included. There was a significant negative correlation between ASPECTS and DWI lesion volume (r=-0.78; P<0.0001). With regards to lesion localization, correlation was weaker in deep MCA region (r=-0.19; P=0.038) when compared with superficial (r=-0.72; P<0.001) or combined superficial and deep MCA lesions (r=-0.72; P<0.001). Receiver-operating characteristics analysis revealed ASPECTS</=6 as best cutoff to identify >/=100-mL DWI lesion volume; however, positive predictive value was low (0.35). CONCLUSIONS: ASPECTS has limitations when lesion location is not considered. Identification of patients with malignant profile by DWI-ASPECTS may be unreliable. ASPECTS may be a useful tool for the evaluation of noncontrast computed tomography. However, if MRI is used, ASPECTS seems dispensable because lesion volume can easily be quantified on DWI maps.

Abstract:
Neuronal populations that synthesize kisspeptin (KP), neurokinin B (NKB) and substance P (SP) in the hypothalamic infundibular nucleus of humans are partly overlapping. These cells are important upstream regulators of gonadotropin-releasing hormone (GnRH) neurosecretion. Homologous neurons in laboratory animals are thought to modulate episodic GnRH secretion primarily via influencing KP receptors on the hypophysiotropic fiber projections of GnRH neurons. To explore the structural basis of this putative axo-axonal communication in humans, we analyzed the anatomical relationship of KP-immunoreactive (IR), NKB-IR and SP-IR axon plexuses with hypophysiotropic GnRH fiber projections. Immunohistochemical studies were carried out on histological samples from postmenopausal women. The neuropeptide-IR axons innervated densely the portal capillary network in the postinfundibular eminence. Subsets of the fibers formed descending tracts in the infundibular stalk, some reaching the neurohypophysis. KP-IR, NKB-IR and SP-IR plexuses intermingled, and established occasional contacts, with hypophysiotropic GnRH fibers in the postinfundibular eminence and through their lengthy course while descending within the infundibular stalk. Triple-immunofluorescent studies also revealed considerable overlap between the KP, NKB and SP signals in individual fibers, providing evidence that these peptidergic projections arise from neurons of the mediobasal hypothalamus. These neuroanatomical observations indicate that the hypophysiotropic projections of human GnRH neurons in the postinfundibular eminence and the descending GnRH tract coursing through the infundibular stalk to the neurohypophysis are exposed to neurotransmitters/neuropeptides released by dense KP-IR, NKB-IR and SP-IR fiber plexuses. Localization and characterization of axonal neuropeptide receptors will be required to clarify the putative autocrine and paracrine interactions in these anatomical regions. (c) 2014 S. Karger AG, Basel.

Abstract:
To explore the link between bioenergetics and mo- tor neuron degeneration, we used a computational model in which detailed morphology and ion conductance are paired with intracellular ATP pro- duction and consumption. We found that reduced ATP availability increases the metabolic cost of a single action potential and disrupts K+/Na+ homeo- stasis, resulting in a chronic depolarization. The magnitude of the ATP shortage at which this ionic instability occurs depends on the morphology and intrinsic conductance characteristic of the neuron. If ATP shortage is confined to the distal part of the axon, the ensuing local ionic instability eventually spreads to the whole neuron and involves fascicula- tion-like spiking events. A shortage of ATP also causes a rise in intracellular calcium. Our modeling work supports the notion that mitochondrial dysfunction can account for salient features of the paralytic disorder amyotrophic lateral sclerosis, including motor neuron hyperexcitability, fascicula- tion, and differential vulnerability of motor neuron subpopulations.

Abstract:
In many species, sexual activity varies on a seasonal basis. Kisspeptin (Kp), a hypothalamic neuropeptide acting as a strong activator of GnRH neurones, plays a critical role in this adaptive process. Recent studies reported that two other neuropeptides, namely neurokinin B (NKB) and dynorphin (DYN), are co-expressed with Kp (and therefore termed KNDy neurones) in the arcuate nucleus and these peptides are also thought to influence GnRH secretion. The aim of this study was to establish whether hypothalamic NKB and DYN expression is photoperiod-dependent in a seasonal rodent, the Syrian hamster, which exhibits robust seasonal rhythms in reproductive activity. The majority of Kp neurones in the arcuate nucleus co-express NKB and DYN and expression of all three peptides is decreased in short, compared to long, photoperiod leading to a 60% decrease in the number of KNDy neurones in photo-inhibitory conditions. In seasonal rodents, RFRP neurones of the dorsomedial hypothalamus are also critical for seasonal reproduction. Interestingly, NKB and DYN are also expressed in the dorsomedial hypothalamus but do not co-localise with RFRP-immunoreactive neurones, and expression of both NKB and DYN is higher in short photoperiod, which is opposite to the short day inhibition of RFRP expression. In conclusion, this study shows that NKB and DYN display different photoperiodic variations in the Syrian hamster hypothalamus. In the arcuate nucleus, NKB and DYN, together with Kp are down-regulated in short photoperiod, whereas in the dorsomedial hypothalamus NKB and DYN are up-regulated in short photoperiod. This article is protected by copyright. All rights reserved.

Abstract:
PURPOSE: To optimize the white-matter-nulled (WMn) Magnetization Prepared Rapid Gradient Echo (MP-RAGE) sequence at 7 Tesla (T), with comparisons to 3T. METHODS: Optimal parameters for maximizing signal-to-noise ratio (SNR) efficiency were derived. The effect of flip angle and repetition time (TR) on image blurring was modeled using simulations and validated in vivo. A novel two-dimensional (2D) -centric radial fan beam (RFB) k-space segmentation scheme was used to shorten scan times and improve parallel imaging. Healthy subjects as well as patients with multiple sclerosis and tremor were scanned using the optimized protocols. RESULTS: Inversion repetition times (TS) of 4.5 s and 6 s were found to yield the highest SNR efficiency for WMn MP-RAGE at 3T and 7T, respectively. Blurring was more sensitive to flip in WMn than in CSFn MP-RAGE and relatively insensitive to TR for both regimes. The 2D RFB scheme had 19% and 47% higher thalamic SNR and SNR efficiency than the 1D centric scheme for WMn MP-RAGE. Compared with 3T, SNR and SNR efficiency were higher for the 7T WMn regime by 56% and 41%, respectively. MS lesions in the cortex and thalamus as well as thalamic subnuclei in tremor patients were clearly delineated using WMn MP-RAGE. CONCLUSION: Optimization and new view ordering enabled MP-RAGE imaging with 0.8-1 mm3 isotropic spatial resolution in scan times of 5 min with whole brain coverage. Magn Reson Med, 2014. (c) 2014 Wiley Periodicals, Inc.

Abstract:
BACKGROUND: The 2010 McDonald criteria allow diagnosing multiple sclerosis (MS) with one magnetic resonance imaging (MRI) scan. Nevertheless, not all patients at risk fulfil criteria at baseline. Other predictive factors (PFs) are: age </=40 years, positive oligoclonal bands (OBs), and >/=3 periventricular lesions. OBJECTIVE: The purpose of this study was to evaluate the 2010 McDonald criteria performance and to assess other PFs in patients without dissemination in space (DIS). METHODS: Patients with clinically isolated syndrome (CIS) underwent baseline MRI and OB determination with clinical and radiological follow-up. Adjusted hazard ratios (aHRs) for clinically definite MS were estimated for DIS, dissemination in time (DIT), and DIS+DIT. Diagnostic properties at two years were calculated. In cases without DIS, combinations of >/=2 PFs were assessed. RESULTS: A total of 652 patients were recruited; aHRs were 3.8 (2.5-5.8) for DIS, 4.2 (1.9-9.2) for DIT, and 8.6 (5.4-13.8) for DIS+DIT. Sensitivities were 69.6%, 42.3%, and 36.4%, and specificities were 67.3%, 87.9%, and 90.2%, respectively. In patients without DIS, aHRs varied between 2.7-5.5 and specificities ranged from 73.5-89.7% for PF combinations. CONCLUSION: The high specificity of the 2010 McDonald criteria is confirmed. In patients without DIS, PF combinations could be helpful in identifying those at risk for MS.

Abstract:
PURPOSE: The aim of this study was to optimize the 3-dimensional (3D) fluid attenuated inversion recovery (FLAIR) pulse sequence for isotropic high-spatial-resolution imaging of white matter (WM) and cortical lesions at 7 T. MATERIALS AND METHODS: We added a magnetization-prepared (MP) FLAIR module to a Cube 3D fast spin echo sequence and optimized the refocusing flip angle train using extended phase graph simulations, taking into account image contrast, specific absorption rate (SAR), and signal-to-noise ratio (SNR) as well as T1/T2 values of the different species of interest (WM, grey matter, lesions) at 7 T. We also effected improved preparation homogeneity at 7 T by redesigning the refocusing pulse used in the MP segments. Two sets of refocusing flip angle trains-(a) an SNR-optimal and (b) a contrast-optimal set-were derived and used to scan 7 patients with Alzheimer disease/cognitive impairment and 7 patients with multiple sclerosis. Conventional constant refocusing flip MP-FLAIR images were also acquired for comparison. Lesion SNR, contrast, and lesion count were compared between the 2 optimized and the standard FLAIR sequences. RESULTS: Whole brain coverage with 0.8 mm isotropic spatial resolution in approximately 5-minute scan times was achieved using the optimized 3D FLAIR sequences at clinically acceptable SAR levels. The SNR efficiency of the SNR-optimal sequence was significantly better than that of conventional constant refocusing flip MP-FLAIR sequence, whereas the scan time was reduced more than 2-fold ( approximately 5 vs >10 minutes). The contrast efficiency of the contrast-optimal sequence was comparable with that of the constant refocusing flip sequence. Lesion load ascertained by lesion counting was not significantly different among the sequences. CONCLUSION: Magnetization-prepared FLAIR-Cube with refocusing flip angle trains optimized for SNR and contrast can be used to characterize WM and cortical lesions at 7 T with 0.8 mm isotropic resolution in short scan times and without SAR penalty.

Abstract:
IMPORTANCE: The safety and efficacy of switching from natalizumab to fingolimod have not yet been evaluated in a large cohort of patients with multiple sclerosis (MS) to our knowledge. OBJECTIVE: To collect data from patients with MS switching from natalizumab to fingolimod. DESIGN, SETTING, AND PARTICIPANTS: The Enquete Nationale sur l'Introduction du Fingolimod en Relais au Natalizumab (ENIGM) study, a survey-based, observational multicenter cohort study among MS tertiary referral centers. Participants were patients for whom a switch from natalizumab to fingolimod was planned. Clinical data were collected on natalizumab treatment, duration and management of the washout period (WP), and relapse or adverse events during the WP and after the initiation of fingolimod. MAIN OUTCOMES AND MEASURES: Occurrence of MS relapse during the WP or during a 6-month follow-up period after the initiation of fingolimod. RESULTS: Thirty-six French MS tertiary referral centers participated. In total, 333 patients with MS switched from natalizumab to fingolimod after a mean of 31 natalizumab infusions (female to male ratio, 2.36; mean age, 41 years; and Expanded Disability Status Scale score at the initiation of natalizumab, 3.6). Seventy-one percent were seropositive for the JC polyomavirus. The Expanded Disability Status Scale score remained stable for patients receiving natalizumab. Twenty-seven percent of patients relapsed during the WP. A WP shorter than 3 months was associated with a lower risk of relapse (odds ratio, 0.23; P = .001) and with less disease activity before natalizumab initiation (P = .03). Patients who stopped natalizumab because of poor tolerance or lack of efficacy also had a higher risk of relapse (odds ratio, 3.20; P = .004). Twenty percent of patients relapsed during the first 6 months of fingolimod therapy. Three percent stopped fingolimod for efficacy, tolerance, or compliance issues. In the multivariate analysis, the occurrence of relapse during the WP was the only significant prognostic factor for relapse during fingolimod therapy (odds ratio, 3.80; P = .05). CONCLUSIONS AND RELEVANCE: In this study, switching from natalizumab to fingolimod was associated with a risk of MS reactivation during the WP or shortly after fingolimod initiation. The WP should be shorter than 3 months.

Abstract:
Cannabinoid receptor type 1 (CB1)-dependent signaling in the brain is known to modulate food intake. Recent evidence has actually shown that CB1 can both inhibit and stimulate food intake in fasting/refeeding conditions, depending on the specific neuronal circuits involved. However, the exact brain sites where this bimodal control is exerted and the underlying neurobiological mechanisms are not fully understood yet. Using pharmacological and electrophysiological approaches, we show that local CB1 blockade in the paraventricular nucleus of the hypothalamus (PVN) increases fasting-induced hyperphagia in rats. Furthermore, local CB1 blockade in the PVN also increases the orexigenic effect of the gut hormone ghrelin in animals fed ad libitum. At the electrophysiological level, CB1 blockade in slices containing the PVN potentiates the decrease of the activity of PVN neurons induced by long-term application of ghrelin. Hence, the PVN is (one of) the site(s) where signals associated with the body's energy status determine the direction of the effects of endocannabinoid signaling on food intake.

Abstract:
Neuropilin-1 (Nrp1) guides the development of the nervous and vascular systems, but its role in the mature brain remains to be explored. Here we report that the expression of the 65 kDa isoform of Sema3A, the ligand of Nrp1, by adult vascular endothelial cells, is regulated during the ovarian cycle and promotes axonal sprouting in hypothalamic neurons secreting gonadotropin-releasing hormone (GnRH), the neuropeptide controlling reproduction. Both the inhibition of Sema3A/Nrp1 signaling and the conditional deletion of Nrp1 in GnRH neurons counteract Sema3A-induced axonal sprouting. Furthermore, the localized intracerebral infusion of Nrp1- or Sema3A-neutralizing antibodies in vivo disrupts the ovarian cycle. Finally, the selective neutralization of endothelial-cell Sema3A signaling in adult Sema3aloxP/loxP mice by the intravenous injection of the recombinant TAT-Cre protein alters the amplitude of the preovulatory luteinizing hormone surge, likely by perturbing GnRH release into the hypothalamo-hypophyseal portal system. Our results identify a previously unknown function for 65 kDa Sema3A-Nrp1 signaling in the induction of axonal growth, and raise the possibility that endothelial cells actively participate in synaptic plasticity in specific functional domains of the adult central nervous system, thus controlling key physiological functions such as reproduction.

Abstract:
The identification of the presence of active signaling between astrocytes and neurons in a process termed gliotransmission has caused a paradigm shift in our thinking about brain function. However, we are still in the early days of the conceptualization of how astrocytes influence synapses, neurons, networks, and ultimately behavior. In this Perspective, our goal is to identify emerging principles governing gliotransmission and consider the specific properties of this process that endow the astrocyte with unique functions in brain signal integration. We develop and present hypotheses aimed at reconciling confounding reports and define open questions to provide a conceptual framework for future studies. We propose that astrocytes mainly signal through high-affinity slowly desensitizing receptors to modulate neurons and perform integration in spatiotemporal domains complementary to those of neurons.

Abstract:
The pituitary gland releases hormones in a pulsatile fashion guaranteeing signalling efficiency. The determinants of pulsatility are poorly circumscribed. Here we show in magnocellular hypothalamo-neurohypophyseal oxytocin (OT) neurons that the bursting activity underlying the neurohormonal pulses necessary for parturition and the milk-ejection reflex is entirely driven by a female-specific central pattern generator (CPG). Surprisingly, this CPG is active in both male and female neonates, but is inactivated in males after the first week of life. CPG activity can be restored in males by orchidectomy or silenced in females by exogenous testosterone. This steroid effect is aromatase and caspase dependent, and is mediated via oestrogen receptor-alpha. This indicates the apoptosis of the CPG network during hypothalamic sexual differentiation, explaining why OT neurons do not burst in adult males. This supports the view that stereotypic neuroendocrine pulsatility is governed by CPGs, some of which are subjected to gender-specific perinatal programming.

Abstract:
BACKGROUND AND PURPOSE: BIONAT is a French multicentric phase IV study of natalizumab (NTZ)-treated relapsing-remitting multiple sclerosis (MS) patients. The purpose of this study was to collect clinical, radiological and biological data on 1204 patients starting NTZ, and to evaluate the clinical/radiological response to NTZ after 2 years of treatment. METHODS: Patients starting NTZ at 18 French MS centres since June 2007 were included. Good response to NTZ was defined by the absence of clinical and radiological activity. Data analysed in this first report on the BIONAT study focus on patients who started NTZ at least 2 years ago (n = 793; BIONAT2Y ). RESULTS: NTZ was discontinued in 17.78% of BIONAT2Y. The proportion of patients without combined disease activity was 45.59% during the first two successive years of treatment. Systematic dosage of anti-NTZantibodies (Abs) detected only two supplementary patients with anti-NTZ Abs compared with strict application of recommendations. A significant decrease of IgG,M concentrations at 2 years of treatment was found. CONCLUSIONS: The efficacy of NTZ therapy on relapsing-remitting MS in a real life setting is confirmed in the BIONAT cohort. The next step will be the identification of biomarkers predicting response to NTZ therapy and adverse events.

Abstract:
Bone cancer pain is a common and disruptive symptom in cancer patients. In cancer pain animal models, massive reactive astrogliosis in the dorsal horn of the spinal cord has been reported. Because astrocytes may behave as driving partners for pathological pain, we investigated the temporal development of pain behavior and reactive astrogliosis in a rat bone cancer pain model induced by injecting MRMT-1 rat mammary gland carcinoma cells into the tibia. Along with the development of bone lesions, a gradual mechanical and thermal allodynia and hyperalgesia as well as a reduced use of the affected limb developed in bone cancer-bearing animals, but not in sham-treated animals. Dorsal horn Fos expression after nonpainful palpation of the injected limb was also increased in bone cancer-bearing animals. However, at any time during the evolution of tumor, there was no increase in glial fibrillary acidic protein (GFAP) immunoreactivity in the dorsal horn. Further analysis at 21days after injection of the tumor showed no increase in GFAP and interleukin (IL) 1beta transcripts, number of superficial dorsal horn S100beta protein immunoreactive astrocytes, or immunoreactivity for microglial markers (OX-42 and Iba-1). In contrast, all these parameters were increased in the dorsal horn of rats 2weeks after sciatic nerve ligation. This suggests that in some cases, bone cancer pain may not be correlated with spinal overexpression of reactive glia markers, whereas neuropathic pain is. Glia may thus play different roles in the development and maintenance of chronic pain in these 2 situations.

Abstract:
OBJECTIVE: To report the 5-year risk and to identify risk factors for the development of a seminal acute or progressive clinical event in a multi-national cohort of asymptomatic subjects meeting 2009 RIS Criteria. METHODS: Retrospectively identified RIS subjects from 22 databases within 5 countries were evaluated. Time to the first clinical event related to demyelination (acute or 12-month progression of neurological deficits) was compared across different groups by univariate and multivariate analyses utilizing a Cox regression model. RESULTS: Data were available in 451 RIS subjects (F: 354 (78.5%)). The mean age at from the time of the first brain MRI revealing anomalies suggestive of MS was 37.2 years (y) (median: 37.1 y, range: 11-74 y) with mean clinical follow-up time of 4.4 y (median: 2.8 y, range: 0.01-21.1 y). Clinical events were identified in 34% (standard error=3%) of individuals within a 5-year period from the first brain MRI study. Of those who developed symptoms, 9.6% fulfilled criteria for primary progressive MS. In the multivariate model, age [hazard ratio (HR): 0.98 (95% CI: 0.96-0.99); p=0.03], sex (male) [HR: 1.93 (1.24-2.99); p=0.004], and lesions within the cervical or thoracic spinal cord [HR: 3.08 (2.06-4.62); p=<0.001] were identified as significant predictors for the development of a first clinical event. INTERPRETATION: These data provide supportive evidence that a meaningful number of RIS subjects evolve to a first clinical symptom. An age <37 y, male sex, and spinal cord involvement appear to be the most important independent predictors of symptom onset.

Abstract:
Over the last decade, the importance of astrocyte-neuron communication in neuronal development and synaptic plasticity has become increasingly clear. Since neuron-astrocyte interactions represent highly dynamic and reciprocal processes, we hypothesized that many astrocyte genes may be regulated as a consequence of their interactions with maturing neurons. In order to identify such neuron-responsive astrocyte genes in vitro, we sought to establish an expedited technique for separation of neurons from co-cultured astrocytes. Our newly established method makes use of cold jet, which exploits different adhesion characteristics of subpopulations of cells (Jirsova etal., 1997), and is rapid, performed under ice-cold conditions and avoids protease-mediated isolation of astrocytes or time-consuming centrifugation, yielding intact astrocyte mRNA with approximately 90% of neuronal RNA removed. Using this purification method, we executed genome-wide profiling in which RNA derived from astrocyte-only cultures was compared with astrocyte RNA derived from differentiating neuron-astrocyte co-cultures. Data analysis determined that many astrocytic mRNAs and biological processes are regulated by neuronal interaction. Our results validate the cold jet as an efficient method to separate astrocytes from neurons in co-culture, and reveals that neurons induce robust gene-expression changes in co-cultured astrocytes.

Abstract:
Kisspeptin (KP)- and neurokinin B (NKB)- synthesizing neurons of the hypothalamic arcuate nucleus play a pivotal role in the regulation of pulsatile gonadotropin-releasing hormone (GnRH) secretion. Unlike in rodents and sheep, the homologous KP and NKB neurons in the human infundibular region rarely express dynorphin- but often exhibit Substance P (SP) immunoreactivity, indicating remarkable species differences in the neurochemical phenotype of these neurons. In search for additional neuropeptides in human KP and NKB neurons, we carried out immunofluorescent studies on hypothalamic sections obtained from five postmenopausal women. Colocalization experiments provided evidence for the presence of cocaine- and amphetamine-regulated transcript (CART) in 47.9+/-6.6% of KP-immunoreactive (IR) and 30.0+/-4.9% of NKB-IR perikarya and in 17.0+/-2.3% of KP-IR and 6.2+/-2.0% of NKB-IR axon varicosities. All three neuropeptides were present in 33.3+/-4.9% of KP-IR and 28.2+/-4.6% of NKB-IR somata, respectively, whereas triple-labeling showed lower incidences in KP-IR (14.3+/-1.8%) and NKB-IR (5.9+/-2.0%) axon varicosities. CART-IR KP and NKB neurons established contacts with other peptidergic cells, including GnRH-IR neurons and also sent projections to the infundibular stalk. KP and NKB fibers with CART often contained SP as well, while being distinct from CART fibers co-containing the orexigenic peptide agouti-related protein. Presence of CART in human, but not rodent, KP and NKB neurons represents a new example of species differences in the neuropeptide repertoire of mediobasal hypothalamic KP and NKB neurons. Target cells, receptor sites and physiological significance of CART in the efferent communication of KP and NKB neurons in primates require clarification.

Abstract:
The current concept of basal ganglia organization and function in physiological and pathophysiological conditions excludes the most numerous cells in the brain, i.e., the astrocytes, present with a ratio of 10:1 neuron. Their role in neurodegenerative condition such as Parkinson's disease (PD) remains to be elucidated. Before embarking into physiological investigations of the yet-to-be-identified 'tripartite' synapses in the basal ganglia in general and the striatum in particular, we therefore characterized anatomically the PD-related modifications in astrocytic morphology, the changes in astrocytic network connections and the consequences on the spatial relationship between astrocytic processes and asymmetric synapses in normal and PD-like conditions in experimental and human PD. Our results unravel a dramatic regulation of striatal astrocytosis supporting the hypothesis of a key role in (dys) regulating corticostriatal transmission. Astrocytes and their various properties might thus represent a therapeutic target in PD.

Abstract:
INTRODUCTION: Cavitary white matter changes are mainly described in leukodystrophies and especially in vanishing white matter disease. Large cavitary lesions are not typical for multiple sclerosis (MS). METHODS: We studied MS patients with large cavitary brain lesions. Patient characteristics, disease onset/duration/subtype, expanded disability status scale (EDSS), mini mental state (MMS), vanishing white matter disease genetic analysis, and MRI characteristics of the cavitary lesions were analyzed. RESULTS: Twenty patients were analyzed (6 men and 14 women). Mean age at disease onset was 37.6 (range 17-58). Mean disease duration was 10 years (range 2-20). Five patients had initial relapsing-remitting MS and nine patients had primary-progressive MS. Mean EDSS was 5.5 (range 2-8). Mean MMS was 20/30. Vanishing white matter disease genetic analysis was performed and negative in seven patients. Inferior corpus callosum lesions were seen in all patients with available sagittal FLAIR sequences. Cavitary lesions were strictly supratentorial, and located inside the diffuse leukoencephalopathy, with often a posterior predominance. CONCLUSION: MS patients with large cavitary lesions seem to represent a MS subgroup, predominantly women, with relatively late disease onset, predominantly primary-progressive type, relatively high EDSS scores, and severe cognitive dysfunction.

Abstract:
Using the ImmunoChip custom genotyping array, we analyzed 14,498 subjects with multiple sclerosis and 24,091 healthy controls for 161,311 autosomal variants and identified 135 potentially associated regions (P < 1.0 x 10(-4)). In a replication phase, we combined these data with previous genome-wide association study (GWAS) data from an independent 14,802 subjects with multiple sclerosis and 26,703 healthy controls. In these 80,094 individuals of European ancestry, we identified 48 new susceptibility variants (P < 5.0 x 10(-8)), 3 of which we found after conditioning on previously identified variants. Thus, there are now 110 established multiple sclerosis risk variants at 103 discrete loci outside of the major histocompatibility complex. With high-resolution Bayesian fine mapping, we identified five regions where one variant accounted for more than 50% of the posterior probability of association. This study enhances the catalog of multiple sclerosis risk variants and illustrates the value of fine mapping in the resolution of GWAS signals.

Abstract:
The place of magnetic resonance imaging (MRI) in the monitoring of patients with multiple sclerosis (MS) is not codified except during the diagnostic phase. Several studies in the literature have shown that lesion load measured on an MRI done at the beginning of the disease or its increase during the first years had a predictive value, although moderate, on the occurrence of long-term disability as measured by the EDSS. Early worsening of brain atrophy during the early stages of the disease is predictive of worsening cognitive impairment in the following years. Perform an MRI is not required when setting up a first-line disease-modifying therapy (DMT) such as an immunomodulatory treatment but it is useful because it can be used as a reference scan in case of treatment failure. The indications of second-line DMTs, whether prescribed in naive patients with an active disease or after failure of a first-line DMT, are based on combined criteria incorporating MRI data acquired in the previous 3 months compared with a recent MRI. Thus the practical criteria for failure of first-line DMTs are partly based on MRI. During interferon therapy, identification of disease activity on an MRI conducted 1 year after the start of the treatment can predict treatment failure in combination with clinical criteria, such as relapses occurring during the first year. Finally, MRI is essential to the safety monitoring of patients on natalizumab to detect progressive multifocal leukoencephalopathies (PML). In patients at high risk for PML, tested positive for JC virus antibodies and having received natalizumab for more than 2 years, it could be proposed to do a short MRI with FLAIR and diffusion weighted imaging sequences every 3 months to detect preclinical PML.

Abstract:
Bone cancer pain is a common and disruptive symptom in cancer patients. In cancer pain animal models, massive reactive astrogliosis in the dorsal horn of the spinal cord has been reported. Because astrocytes may behave as driving partners for pathological pain, we investigated the temporal development of pain behavior and reactive astrogliosis in a rat bone cancer pain model induced by injecting MRMT-1 rat mammary gland carcinoma cells into the tibia. Along with the development of bone lesions, a gradual mechanical and thermal allodynia and hyperalgesia as well as a reduced use of the affected limb developed in bone cancer-bearing animals, but not in sham-treated animals. Dorsal horn Fos expression after nonpainful palpation of the injected limb was also increased in bone cancer-bearing animals. However, at any time during the evolution of tumor, there was no increase in glial fibrillary acidic protein (GFAP) immunoreactivity in the dorsal horn. Further analysis at 21days after injection of the tumor showed no increase in GFAP and interleukin (IL) 1beta transcripts, number of superficial dorsal horn S100beta protein immunoreactive astrocytes, or immunoreactivity for microglial markers (OX-42 and Iba-1). In contrast, all these parameters were increased in the dorsal horn of rats 2weeks after sciatic nerve ligation. This suggests that in some cases, bone cancer pain may not be correlated with spinal overexpression of reactive glia markers, whereas neuropathic pain is. Glia may thus play different roles in the development and maintenance of chronic pain in these 2 situations.

Abstract:
Novel MR image acquisition strategies have been investigated to elicit contrast within the thalamus, but direct visualization of individual thalamic nuclei remains a challenge because of their small size and the low intrinsic contrast between adjacent nuclei. We present a step-by-step specific optimization of the 3D MPRAGE pulse sequence at 7T to visualize the intra-thalamic nuclei. We first measured T1 values within different sub-regions of the thalamus at 7T in 5 individuals. We used these to perform simulations and sequential experimental measurements (n=17) to tune the parameters of the MPRAGE sequence. The optimal set of parameters was used to collect high-quality data in 6 additional volunteers. Delineation of thalamic nuclei was performed twice by one rater and MR-defined nuclei were compared to the classic Morel histological atlas. T1 values within the thalamus ranged from 1400ms to 1800ms for adjacent nuclei. Using these values for theoretical evaluations combined with in vivo measurements, we showed that a short inversion time (TI) close to the white matter null regime (TI=670ms) enhanced the contrast between the thalamus and the surrounding tissues, and best revealed intra-thalamic contrast. At this particular nulling regime, lengthening the time between successive inversion pulses (TS=6000ms) increased the thalamic signal and contrast and lengthening the alpha pulse train time (N*TR) further increased the thalamic signal. Finally, a low flip angle during the gradient echo acquisition (alpha=4 degrees ) was observed to mitigate the blur induced by the evolution of the magnetization along the alpha pulse train. This optimized set of parameters enabled the 3D delineation of 15 substructures in all 6 individuals; these substructures corresponded well with the known anatomical structures of the thalamus based on the classic Morel atlas. The mean Euclidean distance between the centers of mass of MR- and Morel atlas-defined nuclei was 2.67mm (+/-1.02mm). The reproducibility of the MR-defined nuclei was excellent with intraclass correlation coefficient measured at 0.997 and a mean Euclidean distance between corresponding centers of mass found at first versus second readings of 0.69mm (+/-0.38mm). This 7T strategy paves the way to better identification of thalamic nuclei for neurosurgical planning and investigation of regional changes in neurological disorders.

Abstract:
OBJECTIVE: To find biomarkers identifying patients at risk for the development of progressive multifocal leukoencephalopathy (PML) during natalizumab treatment. METHODS: Patients were recruited from 10 European and US cohorts. Of 289 patients with multiple sclerosis (MS), 224 had been treated with natalizumab (18-80 months), 21 received other immune-modulatory treatments, and 28 were untreated. We had access to samples from 16 natalizumab PML patients. Eight of these patients had given blood before the diagnosis of PML. We also analyzed non-natalizumab-treated patients who developed PML (n = 10) and age- and sex-matched healthy donors (n = 31). All flow cytometric assessments were done on previously cryopreserved, viable peripheral blood mononuclear cells. RESULTS: The percentage of l-selectin-expressing CD4+ T cells was significantly lower in patients treated long-term with natalizumab (40.2%) when compared with patients not receiving natalizumab treatment (47.2%; p = 0.016) or healthy controls (61.0%; p < 0.0001). An unusually low percentage (9-fold lower; 4.6%) was highly correlated with the risk of developing PML in the patient group with available pre-PML samples when compared with non-PML natalizumab-treated patients (p </= 0.0001). Samples were gathered between 4 and 26 months before PML diagnosis. CONCLUSIONS: The cell-based assessment of the percentage of l-selectin-expressing CD4 T cells could provide an urgently needed biomarker for individual PML risk assessment.

Abstract:
Within the central nervous system, functions of the ATP-gated receptor-channel P2X4 (P2X4R) are still poorly understood, yet P2X4R activation in neurons and microglia coincides with high or pathological neuronal activities. In this study, we investigated the potential involvement of P2X4R in microglial functions in a model of kainate (KA)-induced status epilepticus (SE). We found that SE was associated with an induction of P2X4R expression in the hippocampus, mostly localized in activated microglial cells. In P2X4R-deficient mice, behavioral responses during KA-induced SE were unaltered. However, 48h post SE specific features of microglial activation, such as cell recruitment and upregulation of voltage-dependent potassium channels were impaired in P2X4R-deficient mice, whereas the expression and function of other microglial purinergic receptors remained unaffected. Consistent with the role of P2X4R in activity-dependent degenerative processes, the CA1 area was partially protected from SE-induced neuronal death in P2X4R-deficient mice compared with wild-type animals. Our findings demonstrate that P2X4Rs are brought into play during neuronal hyperexcitability and that they control specific aspects of microglial activation. Our results also suggest that P2X4Rs contribute to excitotoxic damages by regulating microglial activation.

Abstract:
Recovery of locomotor behavior following spinal cord injury can occur spontaneously in some vertebrates, such as fish, urodele amphibians, and certain reptiles. This review provides an overview of the current status of our knowledge on the anatomical and electrophysiological changes occurring within the spinal cord that lead to, or are associated with the re-expression of locomotion in spinally-transected salamanders. A better understanding of these processes will help to devise strategies for restoring locomotor function in mammals, including humans.

Abstract:
The conditions in which meridional recirculations appear in swirling flows above a fixed wall are analysed. In the classical Bodewadt problem, where the swirl tends towards an asymptotic value away from the wall, the well-known 'tea-cup effect' drives a flow away from the plate at the centre of the vortex. Simple dimensional arguments applied to a single vortex show that if the intensity of the swirl decreases away from the wall, the sense of the recirculation can be inverted, and that the associated flow rate scales with the swirl gradient. If the flow is quasi-2D, the classical tea-cup effect takes place. This basic theory is confirmed by numerical simulations of a square array of steady, electrically driven vortices. Experiments in the turbulent regimes of the same configuration reveal that these mechanisms are active in the average flow and in its fluctuating part. These mechanisms provide an explanation for previously observed phenomena in electrolyte flows. They also put forward a possible mechanism for the generation of helicity in flows close to two-dimensionality, which plays a key role in the transition between 2D and 3D turbulence.

Abstract:
BACKGROUND: Medication Overuse Headache (MOH) can be related in some patients to dependence-related behaviour characterised by craving, a deficit in controlling substance intake, which is associated to orbitofrontal cortex (OFC) dysfunction. The aim of this study was to explore the psychological correlates in MOH patients and the functioning of the OFC through neuropsychological assessment (Iowa Gambling Task: IGT) and to relate it to prognosis at a one year follow-up point. FINDINGS: Seventeen subjects suffering from probable MOH were included and compared to 19 migraineurs and to 17 controls. The results show significant between group differences for behavioural dependence, depression, anxiety, catastrophizing. There were no between group differences for impulsivity. Mean IGT score did not allow differentiation of MOH patients from the other groups, whereas the score was significantly different between opiate abusers and other medication abusers (45 +/-5.7 versus 57.1 +/-8.2, p = 0.019). Among the clinical variables rated at inclusion, the amount of acute headache medication taken per month was the only one predicting the prognosis (RR = 1.05, 95%CI = 1-1.06, p = 0.04). A slight increase in risk of relapse at 1 year was observed in patients with poorer IGT scores (RR = 0.92, 95%CI = 0.85-1, p = 0.05) and higher behavioural-dependence scores (RR = 1.07, 95%CI = 1--1.14, p = 0.05). None of the other psychological variables predicted relapse risk. CONCLUSIONS: These results must be interpreted with caution due to the low number of subjects. They showed a deficit in decision making processes in MOH patients who overuse medications containing psychoactive substances like opiates. Moreover dependence-related variables are related to the prognosis.

Abstract:
OBJECTIVES: To characterize the cognitive abilities of patients with primary progressive multiple sclerosis (PPMS) and relapsing-remitting multiple sclerosis (RRMS) compared with healthy controls (HCs) matched for age, sex, and education level while considering the different characteristics of PPMS and RRMS and to compare the cognitive patterns of these types of multiple sclerosis. METHODS: Forty-one patients with PPMS, 60 patients with RRMS, and 415 HCs were recruited in a cross-sectional study. Controls were divided into 20 groups according to age, sex, and education level. Participants were assessed with a large battery of neuropsychological (NP) tests that included a modified version of the Brief Repeatable Battery, the Stroop test, computerized tests from the Test of Attentional Performance battery, the numerical span test, and the Rey Complex Figure. RESULTS: Patients with PPMS performed worse than their matched HCs on nearly all NP tests. Patients with RRMS performed worse than matched HCs on a computerized digit-symbol substitution task and the alertness test, reaction time for visual scanning, and Paced-Auditory Serial Addition Test-3 seconds. Patients with PPMS had worse NP scores and were more impaired in cognitive domains than patients with RRMS. After controlling for Expanded Disability Status Scale score, the results remained unchanged. CONCLUSION: The patients with PPMS presented with a wide range of cognitive deficits in information processing speed, attention, working memory, executive function, and verbal episodic memory, whereas the impairments in patients with RRMS were limited to information processing speed and working memory compared with their matched HCs. Cognitive deficits were more severe in patients with PPMS than in patients with RRMS.

Abstract:
OBJECTIVE: The purpose of our study was to evaluate the combination of dynamic contrast-enhanced T1-weighted and double-echo gradient-echo MR imaging to distinguish renal oncocytoma with high T2 signal intensity centrally from renal cell carcinoma (RCC). MATERIALS AND METHODS: Between 2006 and 2011, 63 renal tumors (59 patients) presenting with a high signal intensity (SI) central area on T2-weighted sequences were imaged with dynamic contrast-enhanced sequences, including phases later than 5 minutes after contrast injection, and double-echo chemical-shift sequences were selected from our institutional database. Two experienced radiologists visually assessed presence and distribution of signal enhancement of central areas after injection and measured SI changes on opposed-phase images for calculation of the SI index and tumor-to-spleen ratio. Cutoff values were derived from the receiver operating characteristic (ROC) curve. RESULTS: There were 19 oncocytomas (16 patients), 43 RCCs (42 patients), and one leiomyoma. Complete late enhancement of the central area was observed in 14 oncocytomas (74%) and in five RCCs (12%) (p = 0.05). The combination of complete enhancement and SI index lower than 2% (p = 0.02) or tumor-to-spleen ratio higher than -6% (p = 0.001) provided sensitivity of 36% and 55%, specificity of 95% and 97%, positive predictive value of 67% and 86%, and negative predictive value of 84% and 88%, respectively, for diagnosis of oncocytomas. CONCLUSION: Absence of central area SI inversion or presence of a signal drop on chemical-shift imaging may rule out the diagnosis of oncocytoma.

Abstract:
BACKGROUND: Cognitive impairment in multiple sclerosis (MS) primarily applies to information processing speed (IPS). OBJECTIVE: To evaluate psychometric properties of a new digit/symbol substitution test in healthy subjects and patients with MS, and assess its ability to detect IPS impairment in patients with MS. METHODS: A sample of MS patients, 60 relapsing-remitting (RRMS) and 41 primary progressive MS (PPMS), and 415 healthy controls (HCs) underwent an IPS battery, including assessment of reaction times of subtests of the Test of Attentional Performance battery and a newly developed in-house digit/symbol substitution task, the Computerised Speed Cognitive Test (CSCT). The CSCT was additionally evaluated in a second cohort of 31 RRMS and 12 progressive MS patients, for comparison with the Symbol Digit Modalities Test (SDMT). RESULTS: The CSCT had good reliability in both HCs and patients with MS. It showed a weak practice effect at the 6-month time point. This test had good ecological validity in MS patients. There was a strong correlation between the CSCT with the SDMT and with other IPS tests in patients with MS. The CSCT had the best sensitivity for predicting IPS impairment and was one of the most accurate tests among the IPS battery. CONCLUSION: The CSCT appeared as a good candidate for detecting IPS impairment in MS patients.

Abstract:
The association between cognitive impairment, health-related quality of life (HRQoL) and vocational status has been studied in recent years in cross-sectional studies in multiple sclerosis (MS), but longitudinal data are still lacking. This study assesses this association in a sample of 65 newly diagnosed MS patients followed longitudinally. Each patient underwent a standardised clinical assessment, cognitive tests and the HRQoL SEP-59 questionnaire six months after the MS diagnosis (baseline) and seven years later (y7).Vocational status was also established at baseline and at y7 in MS patients. The HRQoL at baseline was severely reduced in MS patients compared with healthy subjects. The independent predictors for HRQoL composite scores at y7 were the baseline depression score and the memory Z-score. Accordingly, 81.5 % of MS patients worked at baseline and only 54.4 % worked at y7. Among the MS patients who did not work at y7, 72.7 % of them were cognitively impaired, while 27.3 % were unimpaired at baseline. The vocational status at y7 was significantly associated with the baseline IPS Z-score, EDSS and age. Vocational status at y7 and its change over 7 years was significantly associated with cognitive deterioration. IPS or memory dysfunction in the early stages of MS is correlated with a decreased level in health perception, independent of fatigue, depression and physical disability. Cognitive impairment at the diagnosis of MS increases the risk of changing vocational status in MS patients seven years later.

Abstract:
Many cellular structures and organelles are too small to be properly resolved by conventional light microscopy. This is particularly true for dendritic spines and glial processes, which are very small, dynamic, and embedded in dense tissue, making it difficult to image them under realistic experimental conditions. Two-photon microscopy is currently the method of choice for imaging in thick living tissue preparations, both in acute brain slices and in vivo. However, the spatial resolution of a two-photon microscope, which is limited to ~350 nm by the diffraction of light, is not sufficient for resolving many important details of neural morphology, such as the width of spine necks or thin glial processes. Recently developed superresolution approaches, such as stimulated emission depletion microscopy, have set new standards of optical resolution in imaging living tissue. However, the important goal of superresolution imaging with significant subdiffraction resolution has not yet been accomplished in acute brain slices. To overcome this limitation, we have developed a new microscope based on two-photon excitation and pulsed stimulated emission depletion microscopy, which provides unprecedented spatial resolution and excellent experimental access in acute brain slices using a long-working distance objective. The new microscope improves on the spatial resolution of a regular two-photon microscope by a factor of four to six, and it is compatible with time-lapse and simultaneous two-color superresolution imaging in living cells. We demonstrate the potential of this nanoscopy approach for brain slice physiology by imaging the morphology of dendritic spines and microglial cells well below the surface of acute brain slices.

Abstract:
PURPOSE: To investigate imaging characteristics of post-embolised meningioma and to determine if SW imaging can delineate tumour ischaemia. MATERIALS AND METHODS: Sixteen patients were studied before and after preoperative embolisation therapy (8 histopathologically determined with ischaemia, 8 with non-ischaemia). In each patient, a slice-wise ROI for the entire tumour was established, and histogram variables (mean, SD, minimum, maximum, histogram width, mode, and peak height) of SW, ADC, CBV, CBF, MTT, and TTP maps were compared between ischaemic and non-ischaemic groups. Changes in SW histogram were correlated with histopathological characteristics. RESULTS: Signal intensity on the SW map tended to decrease in the ischaemic group and partially increased in the non-ischaemic group. A similar trend was observed on the ADC map. The PW histogram showed an MTT increase in ischaemic group; however, CBV did not show significant changes between ischaemic and non-ischaemic groups. Microhaemorrhage was slightly correlated with Deltapeak height in the SW histogram. CONCLUSION: Post-embolisation changes of intrinsic T2-weighted MR contrasts on SW map are most likely associated with alterations in deoxyhaemoglobin levels and arterial blood flow.

Abstract:
Magnetic resonance imaging is an established tool in the management of multiple sclerosis (MS). Loss of blood brain barrier integrity assessed by gadolinium (Gd) enhancement is the current standard marker of MS activity. To explore the complex cascade of the inflammatory events, other magnetic resonance imaging, but also positron emission tomographic markers reviewed in this article are being developed to address active neuroinflammation with increased sensitivity and specificity. Alternative magnetic resonance contrast agents, positron emission tomographic tracers and imaging techniques could be more sensitive than Gd to early blood brain barrier alteration, and they could assess the inflammatory cell recruitment and/or the associated edema accumulation. These markers of active neuroinflammation, although some of them are limited to experimental studies, could find great relevance to complete Gd information and thereby increase our understanding of acute lesion pathophysiology and its noninvasive follow-up, especially to monitor treatment efficacy. Furthermore, such accurate markers of inflammation combined with those of neurodegeneration hold promise to provide a more complete picture of MS, which will be of great benefit for future therapeutic strategies.

Abstract:
In acute stroke magnetic resonance imaging, a 'mismatch' between visibility of an ischemic lesion on diffusion-weighted imaging (DWI) and missing corresponding parenchymal hyperintensities on fluid-attenuated inversion recovery (FLAIR) data sets was shown to identify patients with time from symptom onset </=4.5 hours with high specificity. However, moderate sensitivity and suboptimal interpreter agreement are limitations of a visual rating of FLAIR lesion visibility. We tested refined image analysis methods in patients included in the previously published PREFLAIR study using refined visual analysis and quantitative measurements of relative FLAIR signal intensity (rSI) from a three-dimensional, segmented stroke lesion volume. A total of 399 patients were included. The rSI of FLAIR lesions showed a moderate correlation with time from symptom onset (r=0.382, P<0.001). A FLAIR rSI threshold of <1.0721 predicted symptom onset </=4.5 hours with slightly increased specificity (0.85 versus 0.78) but also slightly decreased sensitivity (0.47 versus 0.58) as compared with visual analysis. Refined visual analysis differentiating between 'subtle' and 'obvious' FLAIR hyperintensities and classification and regression tree algorithms combining information from visual and quantitative analysis also did not improve diagnostic accuracy. Our results raise doubts whether the prediction of stroke onset time by visual image judgment can be improved by quantitative rSI measurements.

Abstract:
Neurons synthesizing neurokinin B (NKB) and kisspeptin (KP) in the hypothalamic arcuate nucleus represent important upstream regulators of pulsatile gonadotropin-releasing hormone (GnRH) neurosecretion. In search of neuropeptides co-expressed in analogous neurons of the human infundibular nucleus (Inf), we have carried out immunohistochemical studies of the tachykinin peptide Substance P (SP) in autopsy samples from men (21-78 years) and postmenopausal (53-83 years) women. Significantly higher numbers of SP-immunoreactive (IR) neurons and darker labeling were observed in the Inf of postmenopausal women than in age-matched men. Triple-immunofluorescent studies localized SP immunoreactivity to considerable subsets of KP-IR and NKB-IR axons and perikarya in the infundibular region. In postmenopausal women, 25.1% of NKB-IR and 30.6% of KP-IR perikarya contained SP and 16.5% of all immunolabeled cell bodies were triple-labeled. Triple-, double- and single-labeled SP-IR axons innervated densely the portal capillaries of the infundibular stalk. In quadruple-labeled sections, these axons formed occasional contacts with GnRH-IR axons. Presence of SP in NKB and KP neurons increases the functional complexity of the putative pulse generator network. First, it is possible that SP modulates the effects of KP and NKB in axo-somatic and axo-dendritic afferents to GnRH neurons. Intrinsic SP may also affect the activity and/or neuropeptide release of NKB and KP neurons via autocrine/paracrine actions. In the infundibular stalk, SP may influence the KP and NKB secretory output via additional autocrine/paracrine mechanisms or regulate GnRH neurosecretion directly. Finally, possible co-release of SP with KP and NKB into the portal circulation could underlie further actions on adenohypophysial gonadotrophs.

Abstract:
We characterized the mechanism and pharmacodynamics of five structurally distinct inhibitors of d-amino acid oxidase. All inhibitors bound the oxidized form of human enzyme with affinity slightly higher than that of benzoate (Kd &#8776; 2-4 &#956;M). Stopped-flow experiments showed that pyrrole-based inhibitors possessed high affinity (Kd &#8776; 100-200 nM) and slow release kinetics (k < 0.01 s(-1)) in the presence of substrate, while inhibitors with pendent aromatic groups altered conformations of the active site lid, as evidenced by X-ray crystallography, and showed slower kinetics of association. Rigid bioisosteres of benzoic acid induced a closed-lid conformation, had slower release in the presence of substrate, and were more potent than benzoate. Steady-state d-serine concentrations were described in a PK/PD model, and competition for d-serine sites on NMDA receptors was demonstrated in vivo. DAAO inhibition increased the spatiotemporal influence of glial-derived d-serine, suggesting localized effects on neuronal circuits where DAAO can exert a neuromodulatory role

Abstract:
BACKGROUND: To validate a rapid questionnaire as a screening tool, because application of the diagnostic revised criteria of the ICHD-II for medication overuse headache (MOH) requires experience for the physician and is time-consuming. METHODS: ICHD-II criteria for probable MOH (pMOH) were transformed in questions formulated in such a way that they could be self-administered, easily understood, and quickly filled out. We compared this questionnaire to the gold standard: the diagnosis made by headache specialists, based on the the ICHD-II criteria. Patients who were consulting for pMOH or migraine for the first time were consecutively included. As validity indicators, we calculated sensitivity, specificity, positive and negative predictive values of the items. RESULTS: Seventy-nine patients were screened, 77 included, 2 female patients excluded. Forty-two patients have been considered as suffering from pMOH, 35 patients suffered from migraine without medication overuse. The association of the question 'do you take a treatment for attacks more than 10 days per month' and the question 'is this intake on a regular basis?' had a sensitivity of 95.2% and a specificity of 80%. CONCLUSION: This screening tool can detect pMOH with a sensitivity that could be of interest to screen patients in clinical practice and to pre-include patients for research as epidemiological studies.

Abstract:
Resting microglial cells in the brain scan their environment with their processes, primed to react to injury and disease. In this issue of Developmental Cell, Li and colleagues (2012) report that resting microglia also react to physiological neuronal activity, sending their processes toward highly active neurons to regulate their excitability.

Abstract:
BACKGROUND: Existing methods to predict recovery after severe traumatic brain injury lack accuracy. The aim of this study is to determine the prognostic value of quantitative diffusion tensor imaging (DTI). METHODS: In a multicenter study, the authors prospectively enrolled 105 patients who remained comatose at least 7 days after traumatic brain injury. Patients underwent brain magnetic resonance imaging, including DTI in 20 preselected white matter tracts. Patients were evaluated at 1 yr with a modified Glasgow Outcome Scale. A composite DTI score was constructed for outcome prognostication on this training database and then validated on an independent database (n=38). DTI score was compared with the International Mission for Prognosis and Analysis of Clinical Trials Score. RESULTS: Using the DTI score for prediction of unfavorable outcome on the training database, the area under the receiver operating characteristic curve was 0.84 (95% CI: 0.75-0.91). The DTI score had a sensitivity of 64% and a specificity of 95% for the prediction of unfavorable outcome. On the validation-independent database, the area under the receiver operating characteristic curve was 0.80 (95% CI: 0.54-0.94). On the training database, reclassification methods showed significant improvement of classification accuracy (P < 0.05) compared with the International Mission for Prognosis and Analysis of Clinical Trials score. Similar results were observed on the validation database. CONCLUSIONS: White matter assessment with quantitative DTI increases the accuracy of long-term outcome prediction compared with the available clinical/radiographic prognostic score.

Abstract:
Peptidergic neurons synthesizing kisspeptin (KP) and neurokinin B (NKB) in the hypothalamic infundibular nucleus have been implicated in negative sex steroid feedback to GnRH neurons. In laboratory rodents, testosterone decreases KP and NKB expression in this region. In the present study, we addressed the hypothesis that the weakening of this inhibitory testosterone feedback in elderly men coincides with enhanced KP and NKB signaling in the infundibular nucleus. This central hypothesis was tested in a series of immunohistochemical studies on hypothalamic sections of male human individuals that were divided into arbitrary 'young' (21-49 yr, n = 11) and 'aged' (50-67 yr, n = 9) groups. Quantitative immunohistochemical experiments established that the regional densities of NKB-immunoreactive (IR) perikarya and fibers, and the incidence of afferent contacts they formed onto GnRH neurons, exceeded several times those of the KP-IR elements. Robust aging-dependent enhancements were identified in the regional densities of KP-IR perikarya and fibers and the incidence of afferent contacts they established onto GnRH neurons. The abundance of NKB-IR perikarya, fibers, and axonal appositions to GnRH neurons also increased with age, albeit to lower extents. In dual-immunofluorescent studies, the incidence of KP-IR NKB perikarya increased from 36% in young to 68% in aged men. Collectively, these immunohistochemical data suggest an aging-related robust enhancement in central KP signaling and a moderate enhancement in central NKB signaling. These changes are compatible with a reduced testosterone negative feedback to KP and NKB neurons. The heavier KP and NKB inputs to GnRH neurons in aged, compared with young, men may play a role in the enhanced central stimulation of the reproductive axis. It requires clarification to what extent the enhanced KP and NKB signaling upstream from GnRH neurons is an adaptive response to hypogonadism or, alternatively, a consequence of a decline in the androgen sensitivity of KP and NKB neurons.

Abstract:
BACKGROUND AND PURPOSE: Hyperintense vessels (HVs) have been observed in fluid-attenuated inversion recovery imaging of patients with acute ischemic stroke and been linked to slow flow in collateral arterial circulation. Given the potential importance of HV, we used a large, multicenter data set of patients with stroke to clarify which clinical and imaging factors play a role in HV. METHODS: We analyzed data of 516 patients from the previously published PRE-FLAIR study (PREdictive value of FLAIR and DWI for the identification of acute ischemic stroke patients</=3 and </=4.5 hours of symptom onset-a multicenter study) study. Patients were studied by MRI within 12 hours of symptom onset. HV were defined as hyperintensities in fluid-attenuated inversion recovery corresponding to the typical course of a blood vessel that was not considered the proximal, occluded main artery ipsilateral to the diffusion restriction. Presence of HV was rated by 2 observers and related to clinical and imaging findings. RESULTS: Presence of HV was identified in 240 of all 516 patients (47%). Patients with HV showed larger initial ischemic lesion volumes (median, 12.3 versus 4.9 mL; P<0.001) and a more severe clinical impairment (median National Institutes of Health Stroke Scale 10.5 versus 6; P<0.001). In 198 patients with MR angiography, HVs were found in 80% of patients with vessel occlusion and in 17% without vessel occlusion. In a multivariable logistic regression model, vessel occlusion was associated with HV (OR, 21.7%; 95% CI, 9.6-49.9; P<0.001). HV detected vessel occlusion with a specificity of 0.86 (95% CI, 0.80-0.90) and sensitivity of 0.76 (95% CI, 0.69-0.83). CONCLUSIONS: HVs are a common finding associated with proximal arterial occlusions and more severe strokes. HVs predict arterial occlusion with high diagnostic accuracy.

Abstract:
PURPOSE: To compare perfusion-weighted (PW) imaging and apparent diffusion coefficient (ADC) maps in prediction of infarct size and growth in patients with acute middle cerebral artery infarct. MATERIALS AND METHODS: This study was approved by the local institutional review board. Written informed consent was obtained from all 80 patients. Subsequent infarct volume and growth on follow-up magnetic resonance (MR) images obtained within 6 days were compared with the predictions based on PW images by using a time-to-peak threshold greater than 4 seconds and ADC maps obtained less than 12 hours after middle cerebral artery infarct. ADC- and PW imaging-predicted infarct growth areas and infarct volumes were correlated with subsequent infarct growth and follow-up diffusion-weighted (DW) imaging volumes. The impact of MR imaging time delay on the correlation coefficient between the predicted and subsequent infarct volumes and individual predictions of infarct growth by using receiver operating characteristic curves were assessed. RESULTS: The infarct volume measurements were highly reproducible (concordance correlation coefficient [CCC] of 0.965 and 95% confidence interval [CI]: 0.949, 0.976 for acute DW imaging; CCC of 0.995 and 95% CI: 0.993, 0.997 for subacute DW imaging). The subsequent infarct volume correlated (P<.0001) with ADC- (rho=0.853) and PW imaging- (rho=0.669) predicted volumes. The correlation was higher for ADC-predicted volume than for PW imaging-predicted volume (P<.005), but not when the analysis was restricted to patients without recanalization (P=.07). The infarct growth correlated (P<.0001) with PW imaging-DW imaging mismatch (rho=0.470) and ADC-DW imaging mismatch (rho=0.438), without significant differences between both methods (P=.71). The correlations were similar among time delays with ADC-predicted volumes but decreased with PW imaging-based volumes beyond the therapeutic window. Accuracies of ADC- and PW imaging-based predictions of infarct growth in an individual prediction were similar (area under the receiver operating characteristic curve [AUC] of 0.698 and 95% CI: 0.585, 0.796 vs AUC of 0.749 and 95% CI: 0.640, 0.839; P=.48). CONCLUSION: The ADC-based method was as accurate as the PW imaging-based method for evaluating infarct growth and size in the subacute phase.

Abstract:
Accumulative evidence indicates that microglial cells influence the normal development of brain synapses. Yet, the mechanisms by which these immune cells target maturating synapses and influence their functional development at early postnatal stages remain poorly understood. Here, we analyzed the role of CX3CR1, a microglial receptor activated by the neuronal chemokine CX3CL1 (or fractalkine) which controls key functions of microglial cells. In the whisker-related barrel field of the mouse somatosensory cortex, we show that the recruitment of microglia to the sites where developing thalamocortical synapses are concentrated (i.e., the barrel centers) occurs only after postnatal day 5 and is controlled by the fractalkine/CX3CR1 signaling pathway. Indeed, at this developmental stage fractalkine is overexpressed within the barrels and CX3CR1 deficiency delays microglial cell recruitment into the barrel centers. Functional analysis of thalamocortical synapses shows that CX3CR1 deficiency also delays the functional maturation of postsynaptic glutamate receptors which normally occurs at these synapses between the first and second postnatal week. These results show that reciprocal interactions between neurons and microglial cells control the functional maturation of cortical synapses.

Abstract:
Previous immunohistochemical and in situ hybridization studies of sheep, goats, and rodents indicated that kisspeptin (KP), neurokinin B (NKB), and dynorphin A (DYN) are extensively colocalized in the hypothalamic arcuate nucleus, thus providing a basis for the KP/NKB/DYN (KNDy) neuron concept; in both sexes, KNDy neuropeptides have been implicated in the generation of GnRH neurosecretory pulses and in the negative feedback effects of sexual steroids to the reproductive axis. To test the validity and limitations of the KNDy neuron concept in the human, we carried out the comparative immunohistochemical analysis of the three neuropeptides in the infundibular nucleus (Inf; also known as arcuate nucleus) and stalk of young male human individuals (<37 yr). Results of quantitative immunohistochemical experiments established that the regional densities of NKB immunoreactive (IR) perikarya and fibers, and the incidence of afferent contacts they formed onto GnRH neurons, were about 5 times as high as those of the KP-IR elements. Dual-immunofluorescent studies confirmed that considerable subsets of the NKB-IR and KP-IR cell bodies and fibers are separate, and only about 33% of NKB-IR perikarya and 75% of KP-IR perikarya were dual labeled. Furthermore, very few DYN-IR cell bodies could be visualized in the Inf. DYN-IR fibers were also rare and, with few exceptions, distinct from the KP-IR fibers. The abundance and colocalization patterns of the three immunoreactivities showed similar trends in the infundibular stalk around portal blood vessels. Together these results indicate that most NKB neurons in the Inf do not synthesize detectable amounts of KP and DYN in young male human individuals. These data call for a critical use of the KNDy neuron terminology when referring to the putative pulse generator system of the mediobasal hypothalamus. We conclude that the functional importance of these three neuropeptides in reproductive regulation considerably varies among species, between sexes, and at different ages.

Abstract:
It is increasingly accepted that alterations of the early life environment may have lasting impacts on physiological functions. In particular, epidemiological and animal studies have indicated that changes in growth and nutrition during childhood and adolescence can impair reproductive function. However, the precise biological mechanisms that underlie these programming effects of neonatal nutrition on reproduction are still poorly understood. Here, we used a mouse model of divergent litter size to investigate the effects of early postnatal overnutrition and undernutrition on the maturation of hypothalamic circuits involved in reproductive function. Neonatally undernourished females display attenuated postnatal growth associated with delayed puberty and defective development of axonal projections from the arcuate nucleus to the preoptic region. These alterations persist into adulthood and specifically affect the organization of neural projections containing kisspeptin, a key neuropeptide involved in pubertal activation and fertility. Neonatal overfeeding also perturbs the development of neural projections from the arcuate nucleus to the preoptic region, but it does not result in alterations in kisspeptin projections. These studies indicate that alterations in the early nutritional environment cause lasting and deleterious effects on the organization of neural circuits involved in the control of reproduction, and that these changes are associated with lifelong functional perturbations.

Abstract:
N-methyl-d-aspartate receptors (NMDARs) are located in neuronal cell membranes at synaptic and extrasynaptic locations, where they are believed to mediate distinct physiological and pathological processes. Activation of NMDARs requires glutamate and a coagonist whose nature and impact on NMDAR physiology remain elusive. We report that synaptic and extrasynaptic NMDARs are gated by different endogenous coagonists, d-serine and glycine, respectively. The regionalized availability of the coagonists matches the preferential affinity of synaptic NMDARs for d-serine and extrasynaptic NMDARs for glycine. Furthermore, glycine and d-serine inhibit NMDAR surface trafficking in a subunit-dependent manner, which is likely to influence NMDARs subcellular location. Taking advantage of this coagonist segregation, we demonstrate that long-term potentiation and NMDA-induced neurotoxicity rely on synaptic NMDARs only. Conversely, long-term depression requires both synaptic and extrasynaptic receptors. Our observations provide key insights into the operating mode of NMDARs, emphasizing functional distinctions between synaptic and extrasynaptic NMDARs in brain physiology.

Abstract:
BACKGROUND: Exogenous sexual steroids together with pregnancy have been shown to influence the risk of relapses in multiple sclerosis (MS). Treatments used during assisted reproductive techniques may consequently influence the short term evolution of MS by modifying the hormonal status of the patient. The objective of this study was to determine if there was an increased risk of developing exacerbations in women with MS after in vitro fertilisation (IVF). METHODS: MS and IVF data were either automatically extracted from 13 French university hospital databases or obtained from referring neurologists. After matching databases, patient clinical files were systematically reviewed to collect information about MS and the treatments used for IVF. The association between IVF and the occurrence of MS relapses was analysed in detail using univariate and multivariate statistical tests. FINDINGS: During the 11 year study period, 32 women with MS had undergone 70 IVF treatments, 48 using gonadotrophin releasing hormone (GnRH) agonists and 19 using GnRH antagonists. A significant increase in the annualised relapse rate (ARR) was observed during the 3 month period following IVF (mean ARR 1.60, median ARR 0) compared with the same period just before IVF (mean ARR 0.80, median ARR 0) and to a control period 1 year before IVF (mean ARR 0.68, median ARR 0). The significant increase in relapses was associated with the use of GnRH agonists (Wilcoxon paired test, p=0.025) as well as IVF failure (Wilcoxon paired test, p=0.019). INTERPRETATION: An increased relapse rate was observed in this study after IVF in patients with MS and may be partly related both to IVF failure and the use of GnRH agonists.

Abstract:
Neurokinin B (NKB), encoded by Tac2 in rodents, and its receptor, NK3R, have recently emerged as important regulators of reproduction; NKB has been proposed to stimulate kisspeptin output onto GnRH neurons. Accordingly, NKB has been shown to induce gonadotropin release in several species; yet, null or even inhibitory effects of NKB have been also reported. The basis for these discrepant findings, as well as other key aspects of NKB function, remains unknown. We report here that in the rat, LH responses to the NK3R agonist, senktide, display a salient sexual dimorphism, with persistent stimulation in females, regardless of the stage of postnatal development, and lack of LH responses in males from puberty onward. Such dimorphism was independent of the predominant sex steroid after puberty, because testosterone administration to adult females failed to prevent LH responses to senktide, and LH responsiveness was not restored in adult males treated with estradiol or the nonaromatizable androgen, dihydrotestosterone. Yet, removal of sex steroids by gonadectomy switched senktide effects to inhibitory, both in adult male and female rats. Sexual dimorphism was also evident in the numbers of NKB-positive neurons in the arcuate nucleus (ARC), which were higher in adult female rats. This is likely the result of differences in sex steroid milieu during early periods of brain differentiation, because neonatal exposures to high doses of estrogen decreased ARC NKB neurons at later developmental stages. Likewise, neonatal estrogenization resulted in lower serum LH levels that were normalized by senktide administration. Finally, we document that the ability of estrogen to inhibit hypothalamic Tac2 expression seems region specific, because estrogen administration decreased Tac2 levels in the ARC but increased them in the lateral hypothalamus. Altogether, our data provide a deeper insight into relevant aspects of NKB function as major regulator of the gonadotropic axis in the rat, including maturational changes, sexual dimorphism, and differential regulation by sex steroids.

Abstract:
PURPOSE: To compare magnetic resonance (MR) imaging features of multiple sclerosis (MS) lesions after the administration of a gadolinium-based contrast agent and ultrasmall superparamagnetic iron oxide (USPIO) particles among the clinical phenotypes of MS and over time. MATERIALS AND METHODS: This study was approved by the local ethics committee, and written informed consent was obtained from all patients. Twenty-four patients with MS (10 with relapsing and 14 with progressive forms) underwent clinical and gadolinium- and USPIO-enhanced MR examinations at baseline and 6-month follow-up. The number of lesions that enhanced with gadolinium alone, USPIO alone, or both was compared with the Pearson chi2 or Fisher exact test, and lesion sizes were compared with the Wilcoxon Mann-Whitney U test. At 6-month follow-up, the lesion signal intensity on precontrast T1-weighted images and the enhancement after repeat injection of the contrast agent were compared with the baseline postcontrast imaging features by using the McNemar test. RESULTS: Fifty-six lesions were considered active owing to contrast enhancement at baseline; 37 lesions (66%) in 10 patients enhanced with gadolinium. The use of USPIO helped detect 19 additional lesions (34%), and two additional patients were classified as having active disease. Thus, the use of both agents enabled detection of 51% (19 of 37 lesions) more lesions than with gadolinium alone. Enhanced lesions were more frequently observed in the relapsing compared with the progressive forms of MS (P<.0001). USPIO enhancement, in the form of ringlike patterns, could also be observed on T1-weighted images in patients with progressive MS, enabling the detection of five lesions in addition to the five detected with gadolinium in this phenotype. Lesions that enhanced with both contrast agents at baseline were larger (mean size, 6.5 mm+/-3.8; P=.001) and were more likely to persistently enhance at 6-month follow-up (seven of 27 lesions, P<.0001) compared with those that enhanced only with gadolinium (mean size, 4.9 mm+/-2.2; one of nine lesions) or USPIO (mean size, 3.5 mm+/-1.5; 0 of 17 lesions). CONCLUSION: The combination of gadolinium and USPIO in patients with MS can help identify additional active lesions compared with the current standard, the gadolinium-only approach, even in progressive forms of MS. Lesions that enhance with both agents may exhibit a more aggressive evolution than those that enhance with only one contrast agent.

Abstract:
We report here three cases of patients with superior semicircular canal dehiscence syndrome, prospectively monitored pre- and postoperatively. The computed tomography (CT) examination was performed in 0.6 mm slices with multiplanar reconstructions in the plane of the superior semicircular canal. All the patients also had an audiogram and a vestibular evoked myogenic potentials (VEMP) test. Preoperatively, all the patients had dehiscence of more than 3 mm. Conductive hearing loss for frequencies of less than 1000Hz was present in all cases. The VEMP test showed stimulation thresholds lowered to less than 80dB on the affected side. One case of bilateral involvement in the CT image corresponded to unilateral functional impairment. After plugging surgery, all the patients' auditory and/or vestibular systems were improved. In one case, the reconstruction could not be visualised in CT owing to the radiotransparency of certain materials used in the surgical procedure (wax, fascia, cartilage).

Abstract:
OBJECTIVES: Transcutaneous cranial electrical stimulation (TCES) delivers a high-frequency (166 kHz) pulsed biphasic balanced current with a pulse repetition frequency of 100 Hz with 40% duty cycle through a negative electrode and two positive electrodes over the skull. TCES has a proven ability to potentiate anesthesia and analgesia, although the physiological mechanisms of this effect remain unclear. We hypothesized that the mechanism is a modulation of CBF in the central endogenous opioid system. This study aimed at determining the effects of TCES on CBF to elucidate its physiological mechanism. METHODS: Thirty-six healthy volunteers were randomly assigned to active or placebo TCES, and all assessments were double blind. TCES was performed using the Anesthelec device. In the stimulated group, an active cable was used, and in the control group (sham), the cable was inactive. CBF was measured by XeCT before and after two hours of TCES. RESULTS: Globally, CBF was unchanged by TCES. However, locally, TCES induced a significant CBF decrease in the brainstem and thalamus, which are structures involved in pain and anxiety (TCES and control CBF decrease were 18.5 and 11.9 mL/100g brain tissue/min, respectively). CONCLUSION: TCES can modulate local CBF but it has no effect on overall CBF. [Clinical Trials. gov number: NCT00273663].

Abstract:
Estrogen withdrawal increases gonadotropin secretion and body weight, but the critical cell populations mediating these effects are not well understood. Recent studies have focused on a subpopulation of hypothalamic arcuate neurons that coexpress estrogen receptor alpha, neurokinin 3 receptor (NK(3)R), kisspeptin, neurokinin B, and dynorphin for the regulation of reproduction. To investigate the function of kisspeptin/neurokinin B/dynorphin (KNDy) neurons, a novel method was developed to ablate these cells using a selective NK(3)R agonist conjugated to the ribosome-inactivating toxin, saporin (NK(3)-SAP). Stereotaxic injections of NK(3)-SAP in the arcuate nucleus ablated KNDy neurons, as demonstrated by the near-complete loss of NK(3)R, NKB, and kisspeptin-immunoreactive (ir) neurons and depletion of the majority of arcuate dynorphin-ir neurons. Selectivity was demonstrated by the preservation of proopiomelanocortin, neuropeptide Y, and GnRH-ir elements in the arcuate nucleus and median eminence. In control rats, ovariectomy (OVX) markedly increased serum LH, FSH, and body weight, and these parameters were subsequently decreased by treatment with 17beta-estradiol. KNDy neuron ablation prevented the rise in serum LH after OVX and attenuated the rise in serum FSH. KNDy neuron ablation did not completely block the suppressive effects of E(2) on gonadotropin secretion, a finding consistent with redundant pathways for estrogen negative feedback. However, regardless of estrogen status, KNDy-ablated rats had lower levels of serum gonadotropins compared with controls. Surprisingly, KNDy neuron ablation prevented the dramatic effects of OVX and 17beta-estradiol (E(2)) replacement on body weight and abdominal girth. These data provide evidence that arcuate KNDy neurons are essential for tonic gonadotropin secretion, the rise in LH after removal of E(2), and the E(2) modulation of body weight.

Abstract:
BACKGROUND AND PURPOSE: FD stent placement is a promising therapy for challenging intracranial aneurysms. Long-term evaluations about angiographic and morphologic results are still missing. This is the aim of this multicenter series. MATERIALS AND METHODS: We report our experience and 1-year FU in a retrospective chart review of 65 consecutive subjects with 77 unruptured or recanalized aneurysms that were treated with Silk FD stents at 6 centers in France. Both angiographic and clinical results were recorded before treatment and at 6 and 12 months after treatment. At the 12-month FU, relationships between angiographic aneurysm occlusion and shrinkage of the thrombosed aneurysm sac were evaluated. RESULTS: Stent deployment was achieved in 64 cases (98.5%) and failed in 1 case (1.5%). Seven misdeployments of the Silk stent caused the occlusion of 6 parent arteries. Overall acute/subacute procedural morbidity was 7.7%, and mortality was zero. Delayed complications were observed in 10.9% of subjects. At the 6-month FU, permanent morbidity was 7.8% and mortality was 3%. Complete occlusion occurred within 6 months in 68% of aneurysms and within 12 months after treatment in 84.5% of aneurysms. At the 12-month FU, in angiographically complete occluded aneurysms, MR imaging/CT analysis showed the complete disappearance of the thrombosed aneurysm in 30% of cases and partial shrinkage in 52%; furthermore, thrombosed aneurysms were stable in 11% of cases and enlarged in 7%. CONCLUSIONS: The Silk stent is an effective tool for the treatment of challenging aneurysms because it allows complete occlusion in most cases 1 year after treatment. Permanent morbidity was 7.8%, and mortality was 3%.

Abstract:
BACKGROUND: Cognitive impairment in MS impacts negatively on many patients at all disease stages and in all subtypes. Full clinical cognitive assessment is expensive, requiring expert staff and special equipment. Test versions and normative data are not available for all languages and cultures. OBJECTIVE: To recommend a brief cognitive assessment for multiple sclerosis (MS) that is optimized for small centers, with one or few staff members, who may not have neuropsychological training and constructed to maximize international use. METHODS: An expert committee of twelve members representing the main cultural groups that have so far contributed considerable data about MS cognitive dysfunction was convened. Following exhaustive literature review, peer-reviewed articles were selected to cover a broad spectrum of cultures and scales that targeted cognitive domains vulnerable to MS. Each was rated by two committee members and candidates scales were rated on psychometric qualities (reliability, validity, and sensitivity), international application, ease of administration, feasibility in the specified context, and acceptability to patients. Results: The committee recommended the Symbol Digit Modalities Test, if only 5 minutes was available, with the addition of the California Verbal Learning Test - Second Edition and the Brief Visuospatial Memory Test - Revised learning trials if a further 10 minutes could be allocated for testing. CONCLUSIONS: A brief cognitive assessment for MS has been recommended. A validation protocol has been prepared for language groups and validation studies have commenced.

Abstract:
J. Neurochem. (2012) 121, 4-27. ABSTRACT: Neuroglial cells define brain homeostasis and mount defense against pathological insults. Astroglia regulate neurogenesis and development of brain circuits. In the adult brain, astrocytes enter into intimate dynamic relationship with neurons, especially at synaptic sites where they functionally form the tripartite synapse. At these sites, astrocytes regulate ion and neurotransmitter homeostasis, metabolically support neurons and monitor synaptic activity; one of the readouts of the latter manifests in astrocytic intracellular Ca(2+) signals. This form of astrocytic excitability can lead to release of chemical transmitters via Ca(2+) -dependent exocytosis. Once in the extracellular space, gliotransmitters can modulate synaptic plasticity and cause changes in behavior. Besides these physiological tasks, astrocytes are fundamental for progression and outcome of neurological diseases. In Alzheimer's disease, for example, astrocytes may contribute to the etiology of this disorder. Highly lethal glial-derived tumors use signaling trickery to coerce normal brain cells to assist tumor invasiveness. This review not only sheds new light on the brain operation in health and disease, but also points to many unknowns.

Abstract:
N-methyl-D-aspartate receptors (NMDARs) subserve numerous neurophysiological and neuropathological processes in the cerebral cortex. Their activation requires the binding of glutamate and also of a coagonist. Whereas glycine and D-serine (D-ser) are candidates for such a role at central synapses, the nature of the coagonist in cerebral cortex remains unknown. We first show that the glycine-binding site of NMDARs is not saturated in acute slices preparations of medial prefrontal cortex (mPFC). Using enzymes that selectively degrade either D-ser or glycine, we demonstrate that under the present conditions, D-ser is the principle endogenous coagonist of synaptic NMDARs at mature excitatory synapses in layers V/VI of mPFC where it is essential for long-term potentiation (LTP) induction. Furthermore, blocking the activity of glia with the metabolic inhibitor, fluoroacetate, impairs NMDAR-mediated synaptic transmission and prevents LTP induction by reducing the extracellular levels of D-serine. Such deficits can be restored by exogenous D-ser, indicating that the D-amino acid mainly originates from glia in the mPFC, as further confirmed by double-immunostaining studies for D-ser and anti-glial fibrillary acidic protein. Our findings suggest that D-ser modulates neuronal networks in the cerebral cortex by gating the activity of NMDARs and that altering its levels is relevant to the induction and potentially treatment of psychiatric and neurological disorders.

Abstract:
Recently, expression of glutamate decarboxylase-67 (GAD67), a key enzyme of GABA synthesis, was detected in the otherwise glutamatergic mossy fibers of the rat hippocampus. Synthesis of the enzyme was markedly enhanced after experimentally induced status epilepticus. Here, we investigated the expression of GAD67 protein and mRNA in 44 hippocampal specimens from patients with mesial temporal lobe epilepsy (TLE) using double immunofluorescence histochemistry, immunoblotting, and in situ hybridization. Both in specimens with (n = 37) and without (n = 7) hippocampal sclerosis, GAD67 was highly coexpressed with dynorphin in terminal areas of mossy fibers, including the dentate hilus and the stratum lucidum of sector CA3. In the cases with Ammon's horn sclerosis, also the inner molecular layer of the dentate gyrus contained strong staining for GAD67 immunoreactivity, indicating labeling of mossy fiber terminals that specifically sprout into this area. Double immunofluorescence revealed the colocalization of GAD67 immunoreactivity with the mossy fiber marker dynorphin. The extent of colabeling correlated with the number of seizures experienced by the patients. Furthermore, GAD67 mRNA was found in granule cells of the dentate gyrus. Levels, both of GAD67 mRNA and of GAD67 immunoreactivity were similar in sclerotic and nonsclerotic specimens and appeared to be increased compared to post mortem controls. Provided that the strong expression of GAD67 results in synthesis of GABA in hippocampal mossy fibers this may represent a self-protecting mechanism in TLE. In addition GAD67 expression also may result in conversion of excessive intracellular glutamate to nontoxic GABA within mossy fiber terminals.

Abstract:
The gonadotrophin-releasing hormone (GnRH) secreting neurones, which form the final common pathway for the central regulation of reproduction, are directly targeted by kisspeptin (KP) via the G protein-coupled receptor, GPR54. In these multiple labelling studies, we used ovariectomised mice treated with 17beta-oestradiol (OVX + E(2)) or vehicle (OVX + oil) to determine: (i) the ultrastructural characteristics of KP-immunoreactive (IR) afferents to GnRH neurones; (ii) their galanin or neurokinin B (NKB) content; and (iii) the co-expression of galanin or NKB with KP in the two major subpopulations of KP neurones located in the rostral periventricular area of the third ventricle (RP3V) and the arcuate nucleus (Arc). Electron microscopic investigation of the neuronal juxtapositions revealed axosomatic and axodendritic synapses; these showed symmetrical or asymmetrical characteristics, suggesting a phenotypic diversity of KP afferents. Heterogeneity of afferents was also demonstrated by differential co-expression of neuropeptides; in OVX + E(2) mice, KP afferents to GnRH neurones showed galanin-immunoreactivity with an incidence of 22.50 +/- 2.41% and NKB-immunoreactivity with an incidence of 5.61 +/- 2.57%. In OVX + oil animals, galanin-immunoreactivity in the KP afferents showed a major reduction, appearing in only 5.78 +/- 1.57%. Analysis for co-localisation of galanin or NKB with KP was extended to the perikaryal level in animal models, which showed the highest KP incidence; these were OVX + E(2) females for the RP3V and OVX + oil females for the ARC. In the RP3V of colchicine-treated OVX + E(2) animals, 87.84 +/- 2.65% of KP-IR neurones were galanin positive. In the Arc of the colchicine-treated OVX + oil animals, galanin immunoreactivity was detected in only 12.50 +/- 1.92% of the KP expressing neurones. By contrast, the incidence of co-localisation with NKB in the Arc of those animals was 98.09 +/- 1.30%. In situ hybridisation histochemistry of sections from OVX + E(2) animals identified galanin message in more than a third of the KP neurones in the RP3V (38.67 +/- 11.57%) and in the Arc (42.50 +/- 12.52%). These data suggest that GnRH neurones are innervated by chemically heterogeneous KP cell populations, with a small proportion deriving from the Arc group. The presence of galanin within KP axons innervating GnRH neurones and the oestrogen-dependent regulation of that presence add a new dimension to the roles played by galanin in the central regulation of reproduction.

Abstract:
STUDY OBJECTIVE: A computed tomography (CT) scan has high sensitivity in detecting intracranial injury in patients with minor head injury but is costly, exposes patients to high radiation doses, and reveals clinically relevant lesions in less than 10% of cases. We evaluate S100-B protein measurement as a screening tool in a large population of patients with minor head injury. METHODS: We conducted a prospective observational study in the emergency department of a teaching hospital (Bordeaux, France). Patients with minor head injury (2,128) were consecutively included from December 2007 to February 2009. CT scans and plasma S100-B levels were compared for 1,560 patients. The main outcome was to evaluate the diagnostic value of the S100-B test, focusing on the negative predictive value and the negative likelihood ratio. RESULTS: CT scan revealed intracranial lesions in 111 (7%) participants, and their median S100-B protein plasma level was 0.46 mug/L (interquartile range [IQR] 0.27 to 0.72) versus 0.22 mug/L (IQR 0.14 to 0.36) in the other 1,449 patients. With a cutoff of 0.12 mug/L, traumatic brain injuries on CT were identified with a sensitivity of 99.1% (95% confidence interval [CI] 95.0% to 100%), a specificity of 19.7% (95% CI 17.7% to 21.9%), a negative predictive value of 99.7% (95% CI 98.1% to 100%), a positive likelihood ratio of 1.24 (95% CI 1.20 to 1.28), and a negative likelihood ratio of 0.04 (95% CI 0.006 to 0.32). CONCLUSION: Measurement of plasma S100-B on admission of patients with minor head injury is a promising screening tool that may be of help to support the clinician's decision not to perform CT imaging in certain cases of low-risk head injury.

Abstract:
Presynaptic kainate receptors (KARs) exert a modulatory action on transmitter release. We here report that applications of agonists of GluK1-containing KARs in the rat supraoptic nucleus has an opposite action on glutamatergic transmission according to the phenotype of the postsynaptic neuron. Whereas glutamate release was facilitated in oxytocin (OT) neurons, it was inhibited in vasopressin (VP) cells. Interestingly, an antagonist of GluK1-containing KARs caused an inhibition of glutamate release in both OT and VP neurons, revealing the existence of tonically activated presynaptic KARs that are positively coupled to transmitter release. We thus postulated that the inhibition of glutamate release observed with exogenous applications of GluK1 agonists on VP neurons could be indirect. In agreement with this hypothesis, we first showed that functional GluK1-containing KARs were present postsynaptically on VP neurons but not on OT cells. We next showed that the inhibitory effect induced by exogenous GluK1 receptor agonist was compromised when BAPTA was added in the recording pipette to buffer intracellular Ca2+ and block the release of a putative retrograde messenger. Under these conditions, GluK1-containing KAR agonist facilitates glutamatergic transmission in VP neurons in a manner similar to that observed for OT neurons and that resulted from the activation of presynaptic GluK1 receptors. GluK1-mediated inhibition of glutamate release in VP neurons was also blocked by a kappa-opioid receptor antagonist. These findings suggest that activation of postsynaptic GluK1-containing KARs on VP neurons leads to the release of dynorphin, which in turn acts on presynaptic kappa-opioid receptors to inhibit glutamate release.

Abstract:
When animals move, respiration increases to adapt for increased energy demands; the underlying mechanisms are still not understood. We investigated the neural substrates underlying the respiratory changes in relation to movement in lampreys. We showed that respiration increases following stimulation of the mesencephalic locomotor region (MLR) in an in vitro isolated preparation, an effect that persists in the absence of the spinal cord and caudal brainstem. By using electrophysiological and anatomical techniques, including whole-cell patch recordings, we identified a subset of neurons located in the dorsal MLR that send direct inputs to neurons in the respiratory generator. In semi-intact preparations, blockade of this region with 6-cyano-7-nitroquinoxaline-2,3-dione and (2R)-amino-5-phosphonovaleric acid greatly reduced the respiratory increases without affecting the locomotor movements. These results show that neurons in the respiratory generator receive direct glutamatergic connections from the MLR and that a subpopulation of MLR neurons plays a key role in the respiratory changes linked to movement.