Capacities of atrial fibrillation detection after stroke: a French nationwide survey

Background

Atrial fibrillation (AFib) is a major contributor to recurrent but preventable ischemic Stroke (IS)/TIA. However, majority of stroke patients suffer from paroxysmal asymptomatic AFib, which implies stroke health system to implement accurate AFib detection strategies to large scale population. Current practices of AFib screening methods provided by Stroke Units (SU) organization and network in France are currently unknown and uncovered by dedicated guidelines.

Purpose

To assess the methodology of Afib screening in French SU.

Methods

A French Nationwide survey was led (September-November 2020) with on-line structured questionnaires sent to individual targeted stroke-physicians (SP) and heads of SU in France.We analyzed qualitative and quantitative availability and current use of AFib detection tools during acute inhospital and outpatient subacute and chronic post-IS phases.

Results

67% of 140 heads of SU and 33% of SP responded across all continental and overseas French regions.Main clinical characteristics that lead to search Afib are: TIA/IS recurrence under antiplatelet therapy (97%), patient's age (74%), proximal occlusion of a major cerebral artery (72%). Afib is highly suspected when there is: recent brain IS in multiple vascular territories (100%), previous IS in another vascular territory (98%), left atrial enlargement (96%), burst of supraventricular tachycardia <30s (94%). In-hospital cardiac monitoring is considered to be mandatory by 90% of SU teams but only 1/3 of those possess telemetry out of intensive care unit. Outpatient cardiac monitoring is considered of major interest/necessary by 100% of SP. When first line 24-hour Holter monitor is normal and Afib is highly suspected, 75% of the SP required outpatient noninvasive monitoring (NIM) for at least 7 days and more than half required insertable cardiac monitor (ISC). ISC are implanted each year by SU for <10 patients in 44% and <50 patients in 94%. The delay IS-ICM implantation is <1 month in 10%, 1–3 months in 52%, 3–6 months in 29% and >6 months in 9%. Accessibility to outpatient monitoring modalities is graded: fairly easy for 24/48h-Holter (85%) and ISC (68%); rather difficult/impossible for 3–7 days NIM (51%), 8–21 days NIM (75%) or e-ECG tools (99%). Main obstacles to monitoring abilities development in SU were lack of: manpower (80%), efficient network with cardiologists (56%), familiarity of techniques (42%); and technical equipment cost (44%). 96.5% of SU teams deem necessary practice decision support flowchart with cardiologist partnership but 19% use for it.

Conclusion

The survey raises concern about lack of a systematic strategy and shortcomings for Afib detection capacities. These results are a call to establish practice-guidelines and to promote an improvement plan for AFib detection (selection of the patients, tools and prioritization of the exams) after TIA/IS in France which will require a strong collaboration between neurologists and cardiologists.

Funding Acknowledgement

Type of funding sources: Private grant(s) and/or Sponsorship. Main funding source(s): BMS-Pfizer

Neighborhood disparities in stroke and socioeconomic, urban-rural factors using stroke registry

Introduction

Despite major improvements in management over recent decades, stroke remains a devastating disease in Europe and geographic disparities persist. Determining the spatial distribution of stroke may be useful for both epidemiological research and health services planning. The aim of this study was to estimate stroke incidence rates in Pays de Brest (Western France) and to explore the presence of geographic clusters associated with socioeconomic and urban-rural characteristics.

Methods

The study included incidence stroke cases aged 60 years and more from the Stroke Brest registry for the period 2008 to 2013 aggregated at the census block level. Poisson and negative binomial regression models were used to explore determinants of disease risk. Geographically weighted regression (GWR) was used to allow estimation of local regression coefficients.

Results

Between 2008 and 2013, 3088 cases aged 60 years were identified in Pays de Brest. The incidence of stroke was 6.67 per 1 000 inhabitants. Living in a rural neighborhood with a higher level of blue collar and of farmer was associated with higher age adjusted stroke incidence rate ratio (IRR) 1.23, [95%CI 1.09-1.39]. Higher risk was also found in a city center neighborhood with a higher level of blue [IRR 1.22, 95%CI 1.04-1.49]. Local Poisson GWR models achieved the best fit and suggested evidence of spatially varying regression coefficients and clusters of higher incidence.

Conclusions

Our study contributes to a better understanding of the relationship between stroke risks and contextual characteristics such as socioeconomic circumstances and urban rural setting. This will help targeting areas for specific public health prevention.

Key messages

Variations of stroke were marked according to socioeconomic and urban-rural setting of the living area. This study will help targeting areas for specific public health prevention.

Cryptogenic mechanism in ischaemic stroke patients is a predictor of 5-year survival: A population-based study

Introduction

The present study sought to identify factors affecting mortality beyond 28 days in ischaemic stroke patients with whatever ischaemic mechanism.

Patients and methods

A prospective population-based registry was set up in Brest County, Brittany, France. Demographic data, clinical presentation, vascular risk factors and mortality were collected from January 2008 to December 2012. At "home without help" was used as a surrogate marker for low Rankin (0-1) at discharge from the hospital. IS was classified on the TOAST classification. Overall mortality was calculated using the Kaplan-Meier method. Multivariate analysis of mortality beyond 28 days was implemented, using a Cox model, on significant risk factors identified on univariate analysis.

Results

About 3024 IS cases were followed up beyond 28 days. Overall mortality beyond 28 days was 38.49% at 60 months. On multivariate analysis, age (10 years: HR = 1.84; [1.66-2.02]), coronary artery disease (HR = 1.28; [1.05-1.56]), cardiac arrhythmia (HR = 1.36; [1.11-1.67]), peripheral artery disease (HR = 1.66 [1.29-2.13]) and incomplete assessment (HR = 1.39; [1.12-1.74]) were associated with higher mortality risk, whereas female gender (HR = 0.80; [0.68-0.94]), high Glasgow Coma Scale score (GCS > 12) (HR = 0.58; [0.45-0.76]), lacunar syndrome (HR = 0.82; [0.68-0.99], being 'at home without help' (HR = 0.50; [0.41-0.59]) and negative assessment (HR = 0.75; [0.58-0.97], compared to cardioembolism) were associated with better survival probability.

Discussion

Initial clinical status, prior cardiovascular diseases and age was associated with more risk of death: an increment of 10 years almost doubled mortality. Women had more survival probability than men, controlling for age. Ischaemic stroke mechanisms were predictors of late 5-year mortality.

Conclusion

Patients with negative assessment, i.e. representing truly cryptogenic ischaemic stroke, had the best survival probability probably due to fewer atherosclerotic markers.

Cyclin-dependent kinase inhibition with roscovitine: neuroprotection in acute ischemic stroke

Stroke is the third most common cause of mortality and the leading cause of disability in industrialized country. According to population based-studies, ischemic stroke accounts for 67-80% of all strokes. Thrombolysis is used during the acute phase in only 2-5% of ischemic patients. Clinical trials of candidate neuroprotective agents have failed to identify viable therapies for ischemic stroke in humans. There is therefore a great need for new therapeutic strategies, considering that not all brain cells die immediately after ischemic stroke.

Opalski syndrome detected on DWI MRI: A rare lateral medullary infarction. Case report and review

INTRODUCTION

Wallenberg's syndrome and ipsilateral paresis due to combined infarction of the lateral medullary and cervical spinal infarction is known as Opalski syndrome. This rarely described syndrome was reported, to our knowledge, with DWI MRI, only once.

CASE REPORT

We report the case of a 43-year-old man with autosomal dominant polycystic kidney disease who, after a brief episode of coma, developed Wallenberg syndrome and ipsilateral hemiparesis. Initial diffusion weighted-imaging MRI showed a high-intensity signal involving the lateral medulla oblongata and the spinal cord; but FLAIR MRI sequences showed bilateral high-intensity signals in the lateral medulla oblongata and spinal cord and high-intensity signals in the right and left cerebellar hemisphere in the PICA territories. MRI performed one year later showed an infarction involving the left medullary area and adjacent spinal segments alone.

CONCLUSION

This observation illustrates a rare syndrome of lateral medullary infarction, associated with spinal cord infarction related to a possible transient basilar occlusion.

[Metered-dose inhaler with spacer vs nebulization for severe and potentially severe acute asthma treatment in the pediatric emergency department]

OBJECTIVE

To compare treatment with beta 2 agonist delivered either by a spacer device or a nebulizer in children with severe or potentially severe acute asthma.

METHODS

In this randomized trial, children 4 to 15 years, cared for in the emergency department for severe or potentially severe acute asthma, received 6 times either nebulizations of salbutamol (0.15mg/kg) or puffs of a beta 2 agonist (salbutamol 50 microg/kg or terbutaline 125 microg/kg). The primary outcome was the hospitalization rate. Secondary outcomes included percentage improvement in Bishop score, in PEF, SaO(2), respiratory and heart rates, side effects, length of stay and relapses 10 and 30 days later.

RESULTS

Groups did not differ for baseline data. There were no significant differences between the 2 groups (nebulizer N=40, spacer N=39) for baseline characteristics before emergency department consultation except for length of acute asthma in the spacer group. Clinical evolution after treatment, hospitalization rate, relapse were similar including the more severe subgroup. In the spacer group, tachycardia was less frequent (P<0.02). The overall length of stay in the emergency department was significantly shorter (148+/-20 vs 108+/-13 min, P<10(-9)).

CONCLUSIONS

The administration of beta 2 agonist using a metered-dose inhaler with spacer is an effective alternative to nebulizers for the treatment of children with severe or potentially severe acute asthma in the emergency department. Time gained can be used for asthma education.

[Acute osteomyelitis and septic arthritis in children: one year experience]

To describe bacteriologic epidemiology of bone and joint infections, a total of 52 osteomyelitis, 52 arthritis and 20 osteoarthritis of children aged one month to 15 years during a one-year period (2001) were included in a retrospective unicentric review. The mean age was 3,9 +/-3,6 years. Fever and pain were the most common clinical symptoms. The site of infection was single in 95%, involving lower extremities in 80%. Bone scintigraphy was abnormal in 71% of osteomyelitis. Positive cultures was obtained in 29% of all cases (blood cultures: 20%, aspiration cultures: 29%), but in 42% of cases which have both blood and aspiration cultures. Thirty-six bacteria were identified: 19 Staphylococcus (14 aureus), ten Streptococcus (four pneumoniae), three Salmonella, three Kingella kingae, one Moraxella. All the isolates were susceptible to the empiric antibiotic therapy. Outcome was good in 100% of osteomyelitis and in 96% of arthritis.

[An unusual foreign body. Report of a case of subcutaneous emphysema during an asthma attack]

Pneumomediastinum is an uncommon complication after an asthma attack. The essential clinical sign is the presence of subcutaneous emphysema. In the great majority of cases, the treatment of pneumomediastinum corresponds to that of asthma, with resorption over several days. The situation is very different when the development of pneumomediastinum and subcutaneous emphysema is secondary to an aspiration syndrome.

[Smoking and sudden infant death syndrome]

Assessment of the causation relationship between two phenomena requires the demonstration of an epidemiological association, a temporal and asymmetric sequence, and a biological gradient and identification of the biological mechanism(s). All epidemiological studies on sudden infant death syndrome (SIDS) and smoking have encountered major bias and difficult data interpretation but they all have estimated that maternal smoking caused a 2 to 3-fold increased risk of SIDS. Nicotine may interact with non-neuronal nicotinic receptors in the lung, peripheral nicotinic cholinergic and adrenergic chemoreceptors, and brainstem nuclei and has been largely studied. More accurate knowledge concerning the biochemistry and specific features of nicotinic receptors will be useful to explain the way nicotine alters breathing at rest and during hypoxia. Uncertainty about the casual relationship in no way means the fight against smoking is not warranted.

[Effect of racecadotril in the management of acute diarrhea in infants and children]

BACKGROUND

The treatment of diarrhoea relies on the maintenance or restoration of hydration with maintenance of an adequate nutritional intake. Racecadotril has been shown to reduce the stools output during acute diarrhoea. The present work was aimed at measuring the number of emergency department visits for acute diarrhoea either the children received racecadotril or not.

METHOD

Racecadotril and rehydration were compared with rehydration alone in children aged three months to three years who had acute diarrhoea and were evaluated in the emergency department (ED). The primary end point was the number of medical exams during the week after starting treatment. Secondary end points were the number of stools during the first 48 hours, the duration of the diarrhoea and the weight on day 7.

RESULTS

One hundred and sixty-six children were alternatively randomized to the treated and the control groups. There was no difference for age, degree of dehydration and length of illness before the first visit between the groups. Whatever type of rehydration (oral or i.v.), the treated group had a significant lower number of stools (p < 0.001) and a faster recovery (p < 10(-9)). The children receiving racecadotril needed less additional ED visits for the same episode (p < 0.05). There was no difference for the weight-gain on day 7.

CONCLUSIONS

This study demonstrates the efficacy of racecadotril as adjuvant therapy to oral and i.v. rehydration in the treatment of acute diarrhoea and a fewer emergency department second visit before recovery.

[Benefits of ipratropium bromide in the management of asthmatic crises in the emergency department]

BACKGROUND

To determine if the addition of ipratropium bromide in the emergency department (ED) for the treatment of childhood asthma reduces rates of hospitalization and relapses for moderate and severe exacerbations.

METHODS

Patients were given an oral corticosteroid treatment (2 mg/kg) and received every 20 minutes either three nebulizations with albuterol (0.15 mg/kg) and ipratropium bromide (250 micrograms) or six nebulizations with albuterol alone (control group). The primary end point was the need for hospitalization, additional nebulizations or a relapse during the following week. Secondary end point included the effect of age.

RESULTS

One hundred and forty three children, two to 15 years old, were randomized to ipratropium or control groups and 121 were evaluated on day seven. As a whole, the control group was less often hospitalized or in relapse than those treated with three nebulizations of albuterol and ipratropium (17.5% vs 37.9%, p < 0.02). The ipratropium group reached the same result after three additional albuterol nebulizations. The benefit of anticholinergic therapy was observed for children less than six years of age who had a similar rate of success (73.5 vs 75.7%).

CONCLUSION

The association of ipratropium bromide to the first three doses of the albuterol protocol for acute asthma did not act as well as six nebulizations of albuterol alone. The effect was age dependent and two to six years old children needed more attention. Nevertheless the hospitalization rate did not support the use of ipratropium compared with repeated albuterol nebulizations.

[Drugs for pediatric emergencies]

Drugs for pediatric emergencies are useful for respiratory (croup, asthma), cardiologic (hypertensive crisis, acute congestive heart failure, arrhythmias, hypoxic spells), neurologic (seizures), metabolic (dehydration, hypoglycaemia), infectious (meningococcemia) or allergic (anaphylaxis) distresses. Pain management is always important whether to relieve or to prevent the discomfort which would happen during diagnosis or therapeutic procedures.

[Assessing the cost of the first episode of bronchiolitis]

BACKGROUND

Each year, a quarter of the children younger than 24 months has respiratory syncytial virus bronchiolitis. The morbidity among high-risk infants and the possible association with the development of asthma lead to propose preventive measures whose cost-effectiveness relationship is unknown. The present work was aimed at measuring costs of a first attack of bronchiolitis.

METHOD

For children less than two years visited in the emergency department, direct and indirect costs were measured according to the 'Sécurité Sociale' prices. Associated morbidity, the management of care (inpatient versus outpatient), outpatients' outcome two weeks after the visit, socioeconomic data were recorded.

RESULTS

One hundred eighty three children have been studied. The length of stay for 40 hospitalizations was 7.6 +/- 4.3 days. Direct costs were 37,200 +/- 22,000 FF for inpatients, and 1286 +/- 633 F for outpatients. For 113 outpatients' families, indirect costs were 49 working days lost. The way the child was looked after and the unemployment rate in the study were similar to data provided by the National Institute of Statistics and Economic Studies.

CONCLUSION

Because of the variability of the hospitalization rate from one setting to another, overall costs of the epidemic cannot be evaluated. For the policymaker, the greatest costs come from the outpatient care. Others studies will be necessary to evaluate the price of future preventive measures.

Spatiotemporal expression of noncatalytic TrkC NC2 isoform during early and late CNS neurogenesis: a comparative study with TrkC catalytic and p75NTR receptors

The TrkC subfamily of primary high-affinity neurotrophin-3 receptors is composed of catalytic (kinase-containing; TrkC K) and noncatalytic (TrkC NC) isoforms generated by alternative splicing. We previously reported the presence of the mouse noncatalytic TrkC NC2 isoform in regions of neuronal differentiation [Menn, B., Timsit, S., Calothy, G. & Lamballe, F. (1998) J. Comp. Neurol., 401, 47-64]. In order to gain insight into specific roles for TrkC NC2 receptors during CNS neurogenesis, we compared its distribution with that of its catalytic counterparts and the p75NTR receptor in in vivo and in vitro model systems of early and late neuronal differentiation. We found that TrkC NC2 expression coincided with the exit of neuronal progenitors from the cell cycle and was maintained in differentiated cerebellar neurons. We also showed that, whilst TrkC K receptors were expressed both in mitotic and postmitotic cells, TrkC NC2 was present only in differentiating neural stem cell progeny, suggesting its involvement in neuronal and glial cell differentiation. During neuritogenesis of primary neocortical neurons, both TrkC isoforms as well as p75NTR were located in axonal and dendritic processes. However, whilst these various receptors were present in the same neuronal compartments, TrkC NC2 distribution was specifically restricted to distinct areas of extending neurites. Taken together, these findings suggest that spatiotemporal localization of the noncatalytic receptor could account for specific local effects of neurotrophin-3.

[Asthma and the child below 5 years of age: diagnosis and treatment]

Asthma is the most frequent chronic disease in pediatrics and the increase in its prevalence is a major public health problem. Diagnosis may be difficult in the young child, symptomatology most often occurring following a viral infection. It is important not to ignore a foreign body in the airways or fibrocystic disease and asthma remains, particularly in infants, a diagnosis of elimination. Misdiagnosis or insufficient treatment of asthma may risk the development of irreversible histological lesions and also could compromise pulmonary growth and the child's lung reserve. Spacer devices and nebulisers enable inhaled therapy to be administered to very young children. The value of early diagnosis is to institute appropriate treatment notably in severe asthma with inhaled corticosteroid therapy, the aim being to reduce remodelling lesions of the airways. The minimal effective dose should be defined to minimalise side-effects. The treatment of asthma is not restricted to pharmacotherapy: attempts should be made to reduce intercurrent viral infections, domestic pollution (including smoking) and allergenic concentrations. However, as for all chronic diseases, the clinician will encounter poor compliance. The work of education and support of health professionals is fundamental to the management of asthma.

[Asthma in children below 5 years of age: diagnosis and treatment]

Asthma is the most frequent chronic disease in pediatrics and the increase in its prevalence is a major public health problem. Diagnosis may be difficult in the young child, symptomatology most often occurring following a viral infection. It is important not to ignore a foreign body in the airways or fibrocystic disease and asthma remains, particularly in infants, a diagnosis of elimination. Misdiagnosis or insufficient treatment of asthma may risk the development of irreversible histological lesions and also could compromise pulmonary growth and the child's lung reserve. Spacer devices and nebulisers enable inhaled therapy to be administered to very young children. The value of early diagnosis is to institute appropriate treatment notably in severe asthma with inhaled corticosteroid therapy, the aim being to reduce remodelling lesions of the airways. The minimal effective dose should be defined to minimalize side-effects. The treatment of asthma is not restricted to pharmacotherapy: attempts should be made to reduce intercurrent viral infections, domestic pollution (including smoking) and allergenic concentrations. However, as for all chronic diseases, the clinician will encounter poor compliance. The work of education and support of health professionals is fundamental to the management of asthma.

Increased cyclin D1 in vulnerable neurons in the hippocampus after ischaemia and epilepsy: a modulator of in vivo programmed cell death?

Several observations suggest that delayed neuronal death in ischaemia, epilepsy and other brain disorders includes an apoptotic component, involving programmed cell death (PCD). PCD is hypothesized to result, in part, from aberrant control of the cell cycle. Because they are instrumental in mitosis, cyclins D are key markers to evaluate whether neurons indeed progress into the cell cycle in situations of pathology. Therefore, we investigated in rat brains, the expression of cyclins D in the delayed neuronal death that occurs following transient global ischaemia and kainate-induced seizures. Following a four-vessel occlusion insult, quantitative in situ hybridization revealed a highly significant and persistent 100% increase of cyclin D1 mRNA in the vulnerable pyramidal neurons of the CA1 hippocampal region. Ischaemia also induced a smaller and transient cyclin D1 mRNA increase in the resistant CA3 area and dentate gyrus. In contrast, the cyclin D2 and D3 mRNAs, expressed constitutively in the adult rat hippocampus, were not upregulated. Following kainate-induced seizures, cyclin D1 mRNA was induced in the vulnerable CA3 region, and to a lesser extent, in non-vulnerable regions. Cyclin D1 immunohistochemistry revealed increased protein levels in the cytoplasm and nucleus of neurons commited to die after ischaemia. Double labelling experiments indicate that cyclin D1 is also expressed in reactive astrocytes but not in microglial cells. Finally, we report that in neurons, cyclin D1 expression peaks before nuclear condensation and the appearance of DNA fragmentation. We propose that cyclin D1, when expressed at high levels in lesioned neurons, may act as a modulator of apoptosis.

Differential expression of TrkC catalytic and noncatalytic isoforms suggests that they act independently or in association

Members of the trk gene family encode neurotrophin receptors. The trkC locus encodes multiple neurotrophin-3 catalytic and noncatalytic receptor isoforms. We report the molecular cloning and characterization of mouse cDNAs encoding two noncatalytic TrkC receptors: novel isoforms designated as TrkC NC1 and TrkC NC2, the mouse homologue of the TrkC truncated form previously identified in rat (Tsoulfas et al. [1993] Neuron 10:975-990; Valenzuela et al. [1993] Neuron 10:963-974). We extensively analyzed the transcription pattern of these two noncatalytic isoforms and that of the catalytic isoforms by Northern blotting and in situ hybridization. We did not detect trkC NC1 transcripts in embryos, but we found that trkC NC1 expression is restricted to specific areas in adult brain. In contrast, trkC NC2 transcripts are readily detected early during embryogenesis and are expressed predominantly in adult brain and gonads. We also provide the first evidence for the existence of TrkC NC2 protein by using polyclonal antibodies that specifically recognize this isoform. By using in situ hybridization, we show for the first time that trkC NC2 transcripts are found in differentiating fields of maturing neurons and in mature neurons of laminar structures of adult brain. We also report a similarity of localization between trkC NC2 transcripts and markers of oligodendrocyte progenitors in the embryonic spinal cord. Furthermore, our results also show that trkC NC2 and trkC catalytic transcripts could be either codistributed (in the central and peripheral nervous system) or independently expressed, especially outside the nervous system. These results suggest that the TrkC NC2 isoform acts either independently or in association with its catalytic counterpart. Finally, we show that TrkC NC2 is expressed in dendrites of pyramidal neurons of hippocampus and cerebral cortex. We propose that this receptor is involved in proliferation of oligodendrocyte progenitors, neuronal differentiation, and synaptic plasticity and that it may also play a fundamental role in mediating neurotrophin-3 effects outside the nervous system.

Specific interaction between the XNP/ATR-X gene product and the SET domain of the human EZH2 protein

Mutations in the XNP gene result in different inherited disorders, including the ATR-X syndrome which is characterized by mental retardation (MR) associated with alpha-thalaessemia. Amino acid sequence analysis revealed that the XNP protein is a new member of the SNF2-like family, which comprises numerous members involved in a broad range of biological functions: transcriptional regulation, DNA repair and chromosome segregation. Since experiments on fibroblasts from ATR-X patients have provided no evidence for either a DNA repair defect or abnormal chromosome breakage or segregation, it seems more likely that the XNP protein is somehow involved in regulation of gene expression. Recent genetic and biochemical studies have led to the emerging concept that SNF2-like proteins are components of a large protein complex which may exert its functions by modulating chromatin structure. To investigate whether XNP could mediate the activity of gene-specific activators through chromatin remodelling, we performed a yeast two-hybrid analysis using XNP and several human heterochromatin-associated proteins. We found a specific interaction between the XNP and the EZH2 proteins. In light of these observations, we discuss how the XNP protein may regulate gene transcription at the chromatin level.

Evolving isolated hand palsy: a parietal lobe syndrome associated with carotid artery disease

Six patients with cerebral ischaemia who presented evolving isolated hand palsy were studied, five prospectively and one retrospectively. The motor deficit involved only the hand and the wrist in some cases. In almost all cases the motor deficit was pseudo-ulnar. None of them had a Babinski sign, all had mild sensory symptoms or signs in the affected hand. CT and MRI disclosed recent infarctions contralateral to the affected hand, in the white matter of the angular gyrus, in a vascular borderzone. Five had a tight stenosis of the internal carotid artery. The pyramidal tract was anatomically spared in three cases, even considering its parietal origin. Consistent with previous data, our study suggests that the parietal lobe is involved in the control of the motor function of the hand. We propose the existence of a new entity, characterized by an evolving non-pyramidal motor deficit in the hand following infarction of the angular gyrus of the inferior parietal lobe.

In situ expression of PLP/DM-20, MBP, and CNP during embryonic and postnatal development of the jimpy mutant and of transgenic mice overexpressing PLP

We analyzed by in situ hybridization the spatiotemporal expression of dm-20, myelin basic protein (MBP) and 2'-3' cyclic nucleotide phosphodiesterase (CNP) during embryonic and postnatal development of the normal mouse and two plp/dm-20 mutants: the jimpy mouse and a transgenic mouse overexpressing the plp gene. In the central nervous system (CNS) of the normal mouse, dm-20 mRNA was detected at embryonic day (E)9.5 in the laterobasal plate of the diencephalon. The pattern of expression of CNP transcript was superimposable on that of dm-20, but appeared slightly later, at E12.5. MBP mRNA was detected even later (E14.5), and, in addition, only in the caudal (rhombencephalon and spinal cord) territories of expression of dm-20 and CNP. These observations support our previous proposals: (1) dm-20-expressing cells in the germinative neuroepithelium are precursors of oligodendrocytes, and (2) oligodendrocytes emerge from distinct pools of precursors along the neural tube (Timsit et al., 1995). In the jimpy mutant, despite the mutation in the plp gene, cells of the oligodendrocyte lineage developed normally. It is only at the time of myelin deposition that oligodendrocytes die. During embryonic development of the transgenic mutant overexpressing plp, there were no alterations in the spatiotemporal pattern or the level of expression of dm-20 in the CNS, in contrast to the higher levels of dm-20 observed in the peripheral nervous system (PNS).

Tissue inhibitor of metalloproteinases-1 (TIMP-1) is differentially induced in neurons and astrocytes after seizures: evidence for developmental, immediate early gene, and lesion response

We investigated in vivo the expression of the tissue inhibitor of metalloproteinases-1 (TIMP-1) in the rat CNS after kainate (KA)-induced excitotoxic seizures. In situ hybridization revealed that TIMP-1 mRNA is induced rapidly and massively in most regions of the adult forebrain after KA treatment. Neuronal activity seems to be necessary but not sufficient to trigger TIMP-1 induction, because it is not observed in seizing 10-d-old pups, unlike what is observed in 21- and 35-d-old animals after seizures. The rapid induction of TIMP-1 is not prevented by the inhibitor of protein synthesis cycloheximide, suggesting that, after seizures, TIMP-1 is induced in neurons as an immediate early gene (IEG). The initial neuronal upregulation is followed by enhanced expression in astrocytes, as assessed by double-labeling experiments. In the hippocampus rapid increases in mRNA are followed by relatively delayed (8 hr after KA) increases in TIMP-1 immunoreactivity in the perisomatic and dendro-axonic areas, suggesting secretion of the protein. At 3 d after KA treatment, strong immunoreactivity is found in astrocytes and in the cell bodies and dendro-axonic projections of resistant neurons such as the dentate granule cells. Taken together, the results suggest that TIMP-1 may be instrumental for neurons and astrocytes in coupling early cellular events triggered by seizures with the regulation of long-lasting changes involved in tissue reorganization and/or neuroprotection.

Decrease in internal jugular endothelin levels after carotid cross-clamping during human carotid revascularization procedures

Endothelin-1 (ETL-1), a peptide recently isolated from vascular endothelial cells, acts in cerebral arteries in vitro as a potent and long-lasting vasoconstrictor and has been implicated in the development of cerebral vasospasm. To ascertain whether this new vasoconstrictor has any effect on regulation of the cerebral circulation, we measured plasma ETL-1 concentrations in patients undergoing carotid revascularization and attempted to correlate the variations of venous and arterial plasma ETL-1 with the characteristics of the procedure, including cerebral vasospasm. We prospectively studied 11 patients undergoing a total of 14 carotid surgical revascularization procedures (12 endarterectomies, 2 polytetrafluoroethylene bypass grafts from the common to the internal carotid arteries). Before carotid cross-clamping, blood samples were drawn from the internal jugular vein and the healthy common carotid artery proximal to the occlusive lesion to be treated. After endarterectomy, blood samples were withdrawn from the internal, external, and common carotid arteries. After the release of the last clamp, a final aliquot of blood was withdrawn from the internal jugular vein. After plasma extraction on a C2-ethyl microcolumn, plasma endothelin-like immunoreactivity was measured by means of radioimmunoassay with a polyclonal antibody. In 9 of the 11 patients, internal jugular vein ETL-1 concentration decreased statistically significantly after carotid artery cross-clamping (4.2 +/- 1.4 pg/ml vs. 3.9 +/- 1.1 pg/ml; p < 0.05). In the 2 patients in whom ETL-1 levels failed to drop, a shunt was used during the procedure in 1, and the other was the only patient who had an ipsilateral ischemic postoperative stroke. The decrease in internal jugular vein ETL-1 concentration failed to correlate with any of the cross-clamping times. The level of arterial blood ETL-1 remained steady in the common carotid artery before and after cross-clamping (4.5 +/- 1.5 pg/ml vs. 4.6 +/- 0.9 pg/ml). A small, nonsignificant decrease in ETL-1 level was noted in the external and internal carotid arteries after cross-clamping. The decrease in internal jugular vein ETL-1 levels may in part reflect a compensatory response to carotid artery cross-clamping, which could limit the reduction of local cerebral blood flow.

[Unilateral benign episodic mydriasis]

Ophthalmoplegic migraine is a rare phenomenon. In this setting, extrinsic as well as intrinsic fibers of the third nerve are involved. We report 2 cases of isolated, unilateral, remitting, mydriasis and describe 23 other cases already published. CT scan, MRI and angiogram were always normal when performed. The pathophysiology of this syndrome is probably related to a migrainous manifestation.

Embolism across the circle of Willis

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Oligodendrocytes originate in a restricted zone of the embryonic ventral neural tube defined by DM-20 mRNA expression

Products of the PLP gene, proteolipid protein and its isoform DM-20, are the most abundant proteins in CNS myelin, and are markers of the oligodendrocyte, the myelin-forming cell in the CNS. The DM-20 transcript has previously been reported to be expressed in newborn oligodendrocyte progenitor cells and during embryonic development. We have therefore used a DM-20 cRNA probe to follow, by in situ hybridization, the oligodendrocyte lineage during embryonic development. DM-20-expressing cells were first detected at E9.5 in the ventricular germinal layer of the laterobasal plate of the diencephalon. At E14.5, DM-20+ cells had largely disappeared from the diencephalic ventricular germinal layer and had colonized the ventral mantle layer at the posterior part of the basal diencephalon. Between E17.5 and P1, the number of DM-20+ cells increased and progressively invaded the major white matter tracts. In the hindbrain, DM-20+ cells appeared at E12.5 in the caudal part of the rhombencephalon, and at E14.5 all along the ventral spinal cord. Between E14.5 and P1, DM-20+ cells progressively colonized, first ventrally then dorsally, all the spinal cord and more extensively the white matter tracts. At E14.5, a large gap separated, rostrally, the medullary columns from the mantle layer cells in the prosencephalon, suggesting that oligodendrocytes in the mid- and forebrain originate from a different pool of precursors than in the rhombencephalon and the spinal cord. Together, these observations suggest that expression of the DM-20 transcript is an early marker of commitment to the oligodendrocyte lineage, and that oligodendrocyte precursors originate in a ventrally restricted region.

Anomia for proper names after left thalamic infarct

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Proteolipid protein interactions in transfectants: implications for myelin assembly

The proteolipid proteins (PLP and DM20) are major constituents of CNS myelin, but how they are delivered to and organized within the oligodendrocyte plasma membrane is incompletely understood. We have expressed both PLP and DM20 singly or together in a host cell line, HeLa. In either DM20 or PLP transfectants, at early time points (24 hours), the expressed proteins are found within intracellular compartments. In DM20 transfectants, the protein is delivered to the plasma membrane by 48 hours. In HeLa cells, PLP remains intracellular when expressed in the absence of DM20; only when it is coexpressed with DM20 is it transported to the plasma membrane. In cotransfectants, PLP can also be localized to organelles involved in both the protein biosynthetic and the endocytic pathways. Since, in HeLa cells at least, the delivery of PLP to the plasma membrane is facilitated by the coexpression of DM20, we suggest that the two proteins interact intracellularly to form a complex. In some PLP/DM20 cotransfectants, the proteolipids are concentrated in regions of cell-cell contact. The regional accumulation of these proteins at cell-cell interfaces is highly reminiscent of the behavior in transfected cells of another myelin protein, P0, and certain cadherin polypeptides, both of which have readily demonstrable membrane adhesive properties. Our data suggests that at certain stoichiometric ratios, proteolipids can become stabilized at cell surfaces to form adhesive bonds.

[Vertigo of vascular origin]

The concept of vascular origin in vertigo and equilibrium disorders is only a pragmatic clinical tool used to initiate and direct complex, complementary clinical investigation to determine the location (peripheral, central or mixed), the pathophysiological mechanisms and the multiple etiologies of the vestibular disorder. The concept includes focal and systemic ischemic processes and haemorrhagic processes of the posterior fossa. If the vertigo is associated with central neurological signs, the method can lead to certain diagnosis. If such signs are not detected by neurological screening of all the intra-axial signs of the vertebrobasilar regions, the diagnosis is uncertain clinical. Screening associated CT scan and MRI is more reliable than neuro-otological quantification. The major diagnostic difficulty involves TIA. Vertebrobasilar appears to be more heterogeneous than carotid ischemia. Schematic distinction is possible to differentiate thrombo-embolic from hemodynamic TIA. It is based on methodic clinical analysis and complementary investigations that are of unequal value.

The role of the right medial temporal lobe in the control of memory-guided saccades

The role of the hippocampal formation in the control of memory-guided saccades is unclear. We tested two types of memory-guided saccades with short memorization delay in three patients with a lesion affecting the right medial temporal lobe and involving the hippocampal formation. In single memory-guided saccades, testing spatial working memory, the gain of the patient group did not differ from that of an age-matched control group. In contrast, in sequences of memory-guided saccades, testing chronological working memory, there was a marked and significant increase in the percentage of erroneous sequences in patients, compared to controls. These results suggest an important role of the hippocampal formation in the memorization of the chronological order of saccade sequences. In contrast, this structure does not appear to be crucial for spatial working memory, used in single memory-guided saccades.

The proximal region of the MBP gene promoter is sufficient to induce oligodendroglial-specific expression in transgenic mice

To characterize regulatory DNA sequences involved in oligodendroglial expression of myelin basic protein (MBP), transgenic mice carrying a 256 bp fragment of the mouse MBP promoter fused to an Escherichia coli lacZ gene were generated. Of four transgenic families, two (lines 2 and 4) expressed beta-galactosidase activity in the nervous system but not in most other tissues. Histochemical and immunohistochemical analysis of adult brain from these two lines showed oligodendroglial-specific expression of the transgene. In line 2, only a small proportion of oligodendrocytes expressed the transgene, and in labelled cells the product of the enzymatic reaction with beta-galactosidase was confined to a small round vesicle in the vicinity of the nucleus. In contrast, in tissue sections from line 4 adult brain and spinal cord beta-galactosidase activity was much more intense and at least 80-90% of oligodendrocytes expressed the transgene. Detection of the MBP-lacZ transcript by in situ hybridization showed that the transgene mRNA was confined to the oligodendrocyte cell body. These results suggest that cis-acting regulatory elements, specifying oligodendrocytes identity, are located within 256 bp upstream from the MBP gene.

The DM20 protein of myelin: intracellular and surface expression patterns in transfectants

DM20 is an abundant CNS myelin-specific protein whose role in myelinogenesis is unknown. We have cloned the DM20 cDNA from adult mouse brain total RNA using the polymerase chain reaction and expressed it in HeLa cells. DM20, detected by immunofluorescence in stable transfectants, is present in some cells in large, intensely fluorescent intracellular clumps that probably represent elements of the rough endoplasmic reticulum and Golgi apparatus. Frequently, intense DM20 fluorescence could be detected at the plasma membrane. These findings are consistent with previous studies demonstrating that an intracellular "pool" of DM20 and its larger isoform, proteolipid protein, exists and that a substantial lag occurs between synthesis and insertion of these proteins into the expanding myelin membrane. Permanent DM20 expressors in contact with one another do not display any ultrastructural rearrangements at regions of cell-cell contact, in contrast to what we have previously reported for P0, a PNS-specific protein shown to mediate adhesion of the extracellular faces of the Schwann cell during PNS myelinogenesis. We believe that these results indicate that if DM20 is indeed an adhesion molecule, this property is likely to be significantly more subtle than P0-mediated adhesion.