Elevated levels of IFNγ and LIGHT in the spinal cord of patients with sporadic amyotrophic lateral sclerosis

BACKGROUND

Amyotrophic lateral sclerosis (ALS) is a paralytic and fatal neurodegenerative disorder caused by the gradual loss of both upper and lower motoneurons. There is compelling evidence from ALS experimental models that neuroinflammation actively contributes to motoneuron damage. We recently proposed that interferon gamma (IFNγ), a potent proinflammatory cytokine, induces motoneuron death by eliciting the activation of the lymphotoxin beta receptor (LT-βR) through its ligand LIGHT. Here, we explore the pertinence of this non-cell-autonomous mechanism in human ALS.

METHODS

The levels and expression pattern of IFNγ, LIGHT, and LT-βR were investigated by Western blot and immunohistochemical analysis in spinal cord of patients with sporadic ALS.

RESULTS

  We observed significant increased levels of IFNγ in human ALS spinal cords compared to control cases. We found that large ventral horn neurons as well as glial cells were immunoreactive for IFNγ in sporadic ALS spinal cord. We further observed that LIGHT and LT-βR were expressed mainly by motoneurons in both ALS and control cases, and while LT-βR levels remained constant between ALS and control cases, LIGHT levels were increased in human ALS spinal cords.

CONCLUSION

These findings in sporadic ALS cases, which are consistent with the observation made in ALS experimental models, propose that the IFNγ-triggered LIGHT/LT-βR-mediated death pathway may contribute to human ALS pathogenesis.

Quantification of surviving cerebellar granule neurones and abnormal prion protein (PrPSc) deposition in sporadic Creutzfeldt-Jakob disease supports a pathogenic role for small PrPSc deposits common to the various molecular subtypes

AIMS

Neuronal death is a major neuropathological hallmark in prion diseases. The association between the accumulation of the disease-related prion protein (PrP(Sc) ) and neuronal loss varies within the wide spectrum of prion diseases and their experimental models. In this study, we investigated the relationships between neuronal loss and PrP(Sc) deposition in the cerebellum from cases of the six subtypes of sporadic Creutzfeldt-Jakob disease (sCJD; n=100) that can be determined according to the M129V polymorphism of the human prion protein gene (PRNP) and PrP(Sc) molecular types.

METHODS

The numerical density of neurones was estimated with a computer-assisted image analysis system and the accumulation of PrP(Sc) deposits was scored.

RESULTS

The scores of PrP(Sc) immunoreactive deposits of the punctate type (synaptic type) were correlated with neurone counts - the higher the score the higher the neuronal loss - in all sCJD subtypes. Large 5- to 50-µm-wide deposits (focal type) were found in sCJD-MV2 and sCJD-VV2 subtypes, and occasionally in a few cases of the other studied groups. By contrast, the highest scores for 5- to 50-µm-wide deposits observed in sCJD-MV2 subtype were not associated with higher neuronal loss. In addition, these scores were inversely correlated with neuronal counts in the sCJD-VV2 subtype.

CONCLUSIONS

These results support a putative pathogenic role for small PrP(Sc) deposits common to the various sCJD subtypes. Furthermore, the observation of a lower loss of neurones associated with PrP(Sc) type-2 large deposits is consistent with a possible 'protective' role of aggregated deposits in both sCJD-MV2 and sCJD-VV2 subtypes.

Creutzfeldt-Jakob disease with slow progression. A mimickry of progressive supranuclear palsy

Sporadic Creutzfeldt-Jakob disease (sCJD) does not always present with typical clinical signs, such as myoclonus in association with periodic sharp-wave complexes. We present a 67-year old female patient with initial falls and vertical gaze palsy, suggesting the diagnosis of Progressive Supranuclear Palsy (PSP). EEG and MRI were not contributory. Typical clinical and paraclinical CJD signs were only seen after 17 months. The diagnosis was confirmed by autopsy. - CJD can be a neurodegenerative chameleon. The present case adds to the scare literature of slowly evolving CJD mimicking Parkinsonism related to tauopathies.

Compassionate use of quinacrine in Creutzfeldt–Jakob disease fails to show significant effects

Quinacrine has been reported as an antiprion agent and proposed as an immediately applicable treatment for Creutzfeldt–Jakob disease (CJD). The authors report the results of an open compassionate procedure to which 32 CJD patients had access. In some genotypic subgroups, a slight but nonsignificant increase in survival was observed, likely due to biased inclusion of long-term surviving patients. There was no pathologic evidence of a beneficial effect of quinacrine treatment.

Prion-like protein Doppel expression is not modified in scrapie-infected cells and in the brains of patients with Creutzfeldt-Jakob disease

Doppel protein has been discovered in prnp knock-out mouse lines, with overproduction of this protein in the brain causing ataxia and neurodegeneration. We investigated whether Doppel expression (i) affected or was affected by the course of prion propagation in neuroblastoma cells, or (ii) modulated Creutzfeldt-Jakob disease pathogenesis. No change in Doppel production was detected in N2a cells, before or after infection. Transient murine Doppel gene expression had no effect on N2a viability or PrP(Sc) production. A sensitive immunometric assay revealed low levels of Doppel in human brain, reflecting weak transcription of the corresponding gene. No difference in brain Doppel levels was observed between Creutzfeldt-Jakob disease patients and controls, adding further evidence that Doppel is unlikely to be involved in prion disease pathogenesis.

[Usefulness of molecular genetic analysis of the PRNP gene in patients with cerebellar ataxia: a new case of fatal familial insomnia]

We report the fifth French case of fatal familial insomnia, characterized by a mutation at codon 178 of prion protein gene and by heterozygoty (Met/Val) at codon 129. The clinical picture included cerebellar ataxia, dysautonomia and frontal lobe syndrome. Prion protein gene analysis was performed in order to support a diagnosis of Creutzfeldt-Jakob disease and assert the diagnosis of fatal familial insomnia. Neuropathologic analysis showed unusual changes including severe neuronal loss in the inferior olive and the dentate nucleus, and absence of obvious lesions in the thalamus. Moreover, spongiform changes were moderate in the superior temporal cortex and the occipital cortex. There was no spongiform change in frontal cortex. Abnormal prion protein (PrP(res)) was mainly evidenced in the parietal cortex. Molecular genetic study of the PRNP gene should be performed in patients who present with a cerebellar ataxia of equivocal origin.

[Associations of patients and tissue banks]

Research dealing with tissue is more important to day than ever. Techniques of molecular genetics have indeed permitted the identification of a large number of new proteins that have now to be localised in the tissue and in the cell, in health and disease. This step has to be made in order to elaborate the adequate animal models in which new therapeutics can be tested. In France, however, human tissue samples have become difficult to obtain. Many factors contributed to this situation. Autopsies are now exceptionally performed. Doctors feel confident in their diagnosis and express rarely the need to control it. Families are opposed to post mortem more strongly than before, especially when the reasons for performing it can not be explained before the death of the patient. French law now makes the explicit consent of the patient mandatory before any research. This practically limits all post mortem investigations to those that had been planned before death. The possibility of giving tissue post mortem to allow research has to be publicised, particularly by associations of patients. The organisation that should manage to collect and store the samples at a large scale and over the whole country is lacking. Its structure is still discussed: should it be supported by the state itself, by private funding, possibly by the associations of patients themselves? Patients Associations are ready to play a crucial role: they realised that the present system was inefficient, they are presently trying to organise tissue banks; they will finally have to explain to their members why they should care for research, how they could help and how they will have to accept the absence of immediate spectacular results.

Anticardiolipin antibodies in patients with multiple sclerosis do not represent a subgroup of patients according to clinical, familial, and biological characteristics

BACKGROUND

In multiple sclerosis (MS), case control studies have shown that anticardiolipin antibodies (aCL Ab) are more frequent than in the general population and that aCL Ab positivity may be associated with specific clinical characteristics.

OBJECTIVES

To determine whether patients with MS who are positive for aCL Ab have specific characteristics.

METHODS

285 consecutive patients with MS were tested for aCL Ab positivity. Patients also underwent complete autoimmune screening and were systematically evaluated for clinical characteristics and individual or family history of autoimmune disease.

RESULTS

aCL Ab positivity was found in 42 patients (15%). The main isotype was aCL IgM (32 patients, 11%). Demographics and clinical characteristics including sex, age at onset, course of the disease, expanded disability status scale score, and progression index were not different between aCL Ab positive and aCL Ab negative patients. Clinical systems involved at onset or during the course of the disease were not different from what is usually observed in MS. aCL Ab positivity was not associated with an increased frequency of autoimmune disease and was not predictive of a family history of autoimmune disease. Patients positive for aCL IgM were more frequently positive for the presence of non-organ specific antibodies (53% v 39%, respectively, p = 0.02).

CONCLUSIONS

These results do not support the hypothesis that patients with MS with aCL Ab constitute a subgroup of MS according to demographic clinical and familial characteristics. The greater frequency of other antibodies in aCL Ab positive patients suggests that they only reflect a more general autoimmune activation in MS.

Alpha-synuclein-immunoreactive deposits in human and animal prion diseases

Prion related disorders are associated with the accumulation of a misfolded isoform (PrPsc) of the host-encoded prion protein, PrP. There is strong evidence for the involvement of unidentified co-factors in the PrP to PrPsc conversion process. In this study, we show alpha-synuclein-immunoreactive deposits in the central nervous system of various prion diseases (sporadic, iatrogenic and new variant Creutzfeldt-Jakob diseases, and experimental scrapie of hamsters). alpha-Synuclein accumulated close to PrPsc deposits but we did not observe strict colocalization of prion protein and alpha-synuclein immunoreactivities particularly in PrPsc plaques. alpha-Synuclein is thought to be a key player in some neurodegenerative disorders, is able to interact with amyloid structures and has known chaperone-like activities. Our results, in various prion diseases, suggest a role for alpha-synuclein in regulating PrPsc formation.

VLDL receptor polymorphism, cognitive impairment, and dementia

OBJECTIVE

Clinical, epidemiologic, and pathologic observations suggest that vascular risk factors are associated with impaired cognition. Previous studies supported an association between cognitive decline and APOE. Although the underlying mechanism is not clear, it might involve apoE receptors, such as the very low density lipoprotein receptor.

METHODS

The impact of a polymorphic triplet repeat in the very low density lipoprotein receptor gene (VLDLR) on cognitive function was examined in two independent studies: a population study involving 221 demented subjects compared with 249 control subjects and a clinical study involving 124 demented subjects compared with 179 control subjects.

RESULTS

In the population study, the presence of the VLDLR-5-repeat allele was associated with a relative risk of dementia (OR, 1.9; 95% CI, 1.2 to 3.0). This result was confirmed in the clinical study (OR, 8.1; 95% CI, 4.4 to 15.1) and was more pronounced in subjects with mixed or vascular dementia than in patients with AD.

CONCLUSION

The VLDLR-5-repeat allele may constitute a genetic susceptibility factor for dementia, particularly in the presence of vascular risk factors. This observation suggests the influence of vascular risk factors in the occurrence of dementia.

Neuropathological epidemiology of cerebral aging: a study of two genetic polymorphisms

We studied whether ApoE and -219 GT (ApoE promoter) polymorphism modulates neurofibrillary tangle (NFT) and senile plaque (SP) development in aging among 190 non-institutionalized individuals (mean age 79.5 years). Analysis revealed that the mean Braak stage was higher in epsilon4 allele carriers. Once individuals with Braak stage V were excluded (n = 5), relationships between NFT and the two genotypes studied were weak, whereas in epsilon4 allele carriers, the risk of SP was multiplied by 4 to 7 in four areas (CA1, subiculum, isocortex and entorhinal cortex). This association was more pronounced in subjects under 80 years and was also observed when analysis was restricted to Braak stages 0, I and II. Epsilon 2 allele carriers appeared to have fewer lesions but, due to limited numbers, this trend was not significant. In two regions (CA1, subiculum), the number of SP increased significantly for individuals who were homozygous for the T allele of -219 GT. However the association was no longer significant when controlling for ApoE epsilon4. It should be noted that the brain of elderly subjects carrying one epsilon4 allele may not undergo senile changes.

Dementia with Lewy bodies in a neuropathologic series of suspected Creutzfeldt-Jakob disease

Discriminating Creutzfeldt-Jakob disease (CJD) from dementia with Lewy bodies (DLB) may be clinically difficult to achieve. The authors describe 10 patients with DLB initially referred to the French Network of Human Spongiform Encephalopathies as having suspected CJD. In a series of 465 autopsied cases, DLB ranked second among degenerative alternative diagnoses to CJD. The authors analyzed the factors that contributed to misleading the diagnosis, and suggest that the detection of 14-3-3 protein in CSF may be useful to distinguish CJD from DLB.

[The anatomo-pathologic examination of the brain]

Guidelines for the neuropathological examination of the central nervous system (in adults) are proposed. They include the techniques used for the removal of the brain and spinal cord, the dissection of the skull, the removal of the brain, the fixation of the specimens, the sectioning of the brain, the choice of the blocks for histology, the usual staining methods and the main antibodies to be recommended for immunohistochemistry. Diagrams are given on which the lesions may be drawn and the samples, identified.

[Familial multiple sclerosis: study of 357 consecutive patients]

The empiric recurrence risk of multiple sclerosis (MS) of relatives of French MS patients is not known. Using a standardized interview, we collected the family histones of 357 consecutive patients followed at our MS clinic; adequate information was obtained on 4784 relatives up to the third degree. Thirty-five patients (9.8%) had a relative with MS. The risk-curve for relatives was the same as in other studies conducted with a similar methodology in Canada. England and Flanders. but the crude overall MS recurrence risk for relatives was lower in France. The genetic burden of MS may be lower in France than in areas of higher MS prevalence.

PrP immunohistochemistry: different protocols, including a procedure for long formalin fixation, and a proposed schematic classification for deposits in sporadic Creutzfeldt-Jakob disease

The use of immunohistochemistry on formalin-fixed and paraffin-embedded tissue has greatly improved the neuropathological diagnosis of Creutzfeldt-Jakob disease and the other subacute spongiform encephalopathies in human and animals. Two pitfalls of this technique, however, currently exist: low sensitivity after long formalin fixation and difficulties in interpreting some images. Here we review the protocols currently in use for the pretreatment of sections allowing PrP detection by immunohistochemistry. In addition, a technique useful after long formalin fixation is reported: enzymatic digestion with proteinase K (24 degrees C, 1/100 for 8 minutes) was employed in addition to the usual autoclaving (121 degrees C for 10 minutes) followed by formic acid (99% for 5 minutes) and 4M guanidine thiocyanate (4 degrees C for 2 hours). This allowed a substantial increase in the sensitivity of 3F4 immunohistochemistry on paraffin-embedded tissue, especially after prolonged formalin fixation. In addition, we suggest a simple method for classification of PrP immunolabelling in sporadic Creutzfeldt-Jakob disease that would allow easy comparisons.

Neuropathologic variants of sporadic Creutzfeldt-Jakob disease and codon 129 of PrP gene

OBJECTIVES

To determine the contribution of methionine/valine (Met/Val) polymorphism at codon 129 of the prion protein (PrP) gene in the neuropathologic pattern and mechanisms of lesion development in sporadic Creutzfeldt-Jakob disease.

BACKGROUND

Creutzfeldt-Jakob disease is a transmissible spongiform encephalopathy characterized by a conformational change of PrP and a variety of PrP deposits in the brain, some of which aggregate into amyloid plaques.

METHODS

The authors semiquantitatively assessed neuropathologic lesions and performed PrP immunolabeling in 70 patients (39 Met/Met, 11 Met/Val, 20 Val/Val) who had died in France between 1994 and 1998.

RESULTS

Met/Met cases (mild lesions mostly involving the occipital areas, low PrP load, few focal PrP nonamyloid deposits, no amyloid plaques) contrasted with Met/Val cases (marked lesions especially in the parahippocampal gyrus, high PrP load, numerous amyloid plaques) and with Val/Val cases (younger patients, longer course of disease: 11.5 +/- 3 months, and distinct neuropathology: severe lesions heavily involving the hippocampal formation and basal ganglia, high PrP load, numerous focal nonamyloid deposits, rare amyloid plaques). The course of Val/Val patients younger than age 55 was particularly long (19.9 +/- 7 months), and the isocortex bore the brunt of the pathology, suggesting a distinct variety.

CONCLUSIONS

Polymorphism at codon 129 modulates the phenotype of sporadic Creutzfeldt-Jakob disease. The Val genotype enhances the production of proteinase-resistant PrP, and the Met/Val genotype facilitates its aggregation into amyloid plaques.

[Research on multiple sclerosis and tissue banks]

Tissue banks are of major importance in research on human tissues, in particular as regards the furthering of our knowledge on multiple sclerosis (MS). Individuals who wish to make a 'donation of their brain' for autopsy, or pathologists in possession of biopsy specimens that have not been utilized for diagnosis provide the necessary material for investigation by research teams. In addition to their technical aspects, brain tissue banks provide information and aid in promoting research. Their functioning, usually supported by patient associations, has encountered certain difficulties. At present, it is challenged by a decrease in the number of autopsies.

Autoimmune diseases in families of French patients with multiple sclerosis

Multiple sclerosis (MS) is associated with autoimmune disorders (AIDs) in individual patients, and limited data suggest a possible familial association of MS and AIDs; however, no systematic study has been conducted on the occurrence of AIDs in the families of MS patients. Using a standardized interview focused on AIDs, we obtained the family histories of 357 consecutive patients from our MS clinic. Adequate information was obtained on 1971 first-degree relatives. Fifty-five patients (15.4%) had first-degree relatives with MS (n=22, 6.2%) another AID (n = 30, 8.4%), or both (n = 3, 0.8%). In 16 families (4.5%), at least 3 first-degree relatives had MS or another AID. MS, Grave's disease, rheumatoid arthritis, vitiligo, type 1 insulin-dependent diabetes mellitus, and uveitis, were the most common AIDs in these families. Such multiplex families (families with MS plus AID) are appropriate for identifying susceptibility genes that may be common to MS and other AIDs.

[Fronto-temporal degenerative dementia. A modern neuropathologic approach]

The classification of degenerative dementias with fronto-temporal atrophy has been debated since the description of Pick's disease. The study of a clinico-pathological series of 10 cases using immunohistochemistry lead to the following conclusions: reserving the name of Pick's disease to those cases with argyrophilic inclusions, the most recognisable and characteristic marker at neuropathological examination, allows an easy and reliable diagnosis; keeping on with the splitting of these disorders into various clinico-pathologic entities seems today more useful than grouping them into a single syndrome until new data, based for example on genetic analysis, show that different phenotypes correspond to the same disease.

[Biopathology of transmissible subacute spongiform encephalopathies]

Three lesions can be seen in the central nervous system: vacuolation ("spongiform state"), hypertrophy and proliferation of astrocytes ("astrogliosis"), and neuronal loss. These are poorly specific changes. In contrast, amyloid plaques and other deposits of PrPres are very specific lesions. The recent widening of the clinico-pathological spectrum of PrPres-induced disorders has shown that none of these lesions was constantly present. The mechanisms of PrPres occurrence and development, neuronal death, involvement of the central nervous system after peripheral inoculation are still hypothetical. B lymphocytes, monocyte-macrophages, peripheral nerves, central synapses are important. New data will be provided by experimental models (transgenic mice, transplantations), and by a full study of all patients affected by prion diseases, which necessarily involves autopsy.

DNA breaks detected by in situ end-labelling in dorsal root ganglia of patients with AIDS

Distal sensory axonal polyneuropathy (DSP) is the most frequent HIV-associated peripheral neuropathy. DSPs tend to occur in full-blown AIDS and worsen as CD4 cell counts decrease in blood. To assess a possible role for apoptosis in the pathogenesis of the neuropathy, we used in situ end-labelling (ISEL) detecting DNA strand breaks in DRG neurons of 19 HIV-infected patients, of whom nine had axonal polyneuropathy, and 11 controls. Sensory neurons with ISEL-assessed DNA breaks were observed in 9/19 patients with AIDS, 0/3 patients with pre-AIDS, and 1/11 controls. The prevalence of DNA breaks in neurons was higher in AIDS patients than in controls (P < 0.05). Among AIDS patients, DNA breaks in neurons were more abundant in patients with peripheral neuropathy (P < 0.04). It is possible that DNA breaks of DRG neurons induce the axonopathy and consequently play a role in the pathogenesis of DSP. It cannot be excluded, however, that DNA breaks could represent the result rather than the cause of axonopathy. We suggest that ISEL may detect neurons that were primed to apoptosis before death in relation with the HIV infection, and undergo DNA fragmentation at time of death, rather than neurons that underwent premortem both priming and triggering steps of the apoptotic process. This hypothesis could explain why most ISEL-positive neurons lack typical apoptotic morphology and why normal controls do not show ISEL positive cells.

Identification of crystals in kidneys of AIDS patients treated with foscarnet

Three acquired immune deficiency syndrome patients given foscarnet to treat cytomegalovirus retinitis developed renal failure with crystal deposits within the renal glomeruli. We identified these crystals as a mixture of sodium salt, calcium salt, and a mixed salt containing both sodium and calcium ions. This composition has not been previously reported. Foscarnet can complex available ionized calcium and secondarily precipitate in glomeruli. The percentage of complexing depends on calcium concentration in serum and the poor calcium salt solubility.

[Diseases transmitted by non-conventional agents ("prions"): nosology and diagnosis]

Transmissible non conventional agents are currently called "Prions". This is not a neutral terminology: the attractive Prion hypothesis (the infectious agent being a protein able to replicate in the absence of DNA or RNA) due to Stanley Prusiner is the prevalent one, and has shown to be heuristic, but has not been formally proven and does not easily explain all the data, unless modified and expanded. No simple account has been given for the very unusual physical, chemical, and biological properties of non conventional agents. These infectious agents are associated with degenerative diseases of the nervous system that are either the consequence of a genetic mutation or develop spontaneously in apparently normal individuals, and then can be transmitted to various susceptible hosts, including man. Thus, non conventional agents cannot be considered only as fascinating biological enigmas. They constitute a challenge for public health. The changing characteristics of prion-associated diseases has led to a renewing of their clinical and neuropathological diagnostic criteria. A brief survey of the nosology and neuropathology of prions diseases, with emphasis on new data and on difficulties, is provided. A simple classification based on the familial, sporadic or infectious variety of the disease is suggested. Familial diseases can be named according to the genetic disorder. Sporadic and infectious diseases can be classified following the main clinical symptoms and signs, and the presence or absence of amyloid plaques in the brain, until new tools (analysis of the glycosylation pattern of PrP, strain recognition) allow a more precise nomenclature. The new epidemiology of Prion disorders allowed by these new approaches relies on a full study of Prion diseases affected patients, which necessarily involves their genetic study, and the analysis of brain tissue. This, for practical and ethical reasons, is better achieved by autopsy.

Human immunodeficiency virus type 1 DNA and RNA load in brains of demented and nondemented patients with acquired immunodeficiency syndrome

The relationship between dementia and human immunodeficiency virus type 1 (HIV-1) cerebral load is not clearly understood. We used immunohistochemistry and competitive polymerase chain reaction to evaluate the density ofgp 41 immunostained cells and the amount of HIV-1 DNA and RNA in the midfrontal gyrus of 21 HIV-1 infected patients, nine of whom were demented. The amounts of HIV-1 DNA and RNA, and the density of gp 41-positive cells were significantly linked. In this small series of cases, (1) although as a mean, there was a larger viral load in demented patients than in nondemented, this did not reach the significance level (2) discrepancies appeared in the population under study, some demented patients having low viral loads.

Astrocytic adhesion molecules are increased in HIV-1-associated cognitive/motor complex

Half of AIDS dementia cases are associated with HIV-encephalitis or myelin pallor. Another half die with no HIV-related neuropathological changes. Previous observations suggest that cerebral dysfunction may result from more subtle cellular interactions. and that some of them may be mediated by cell adhesion molecules. In the present study the expression by astrocytes and endothelial cells of intercellular adhesion molecule-1 (ICAM-1), and vascular cell adhesion molecule-1 (VCAM-1) was analysed as a function of the neuropathological diagnosis, the density of astrogliosis and of HIV-1 positive cells, and of the mental status. Twelve AIDS cases, without focal brain lesion, eight of whom were demented, were selected from a prospective study. They were compared with six control cases with multiple sclerosis, and with six control patients without neurological disease. ICAM-1 and VCAM-1 expression was localized by immunofluorescence and confocal microscopy. HIV protein gp41 was detected by immunohistochemistry on adjacent sections. Endothelial expression of ICAM-1 and VCAM-1 was significantly up-regulated in all AIDS patients. VCAM-1 only was related to myelin pallor. The density of VCAM-1 or ICAM-1 positive astrocytes increased in demented AIDS patients, independently of the neuropathological findings or the density of gp41 positive cells. Expression of cell adhesion molecules, together with other secondary mechanisms such as secretion of cytokines may play a role in the pathogenesis of white matter lesions leading to HIV-1-associated cognitive changes.

The neuropathologic diagnostic criteria of frontal lobe dementia revisited. A study of ten consecutive cases

Ten successive cases from the Neuropathology Laboratory of La Salpêtrière Hospital in Paris, were selected on the presence of: dementia and prominent symptoms and signs of the frontal type; a degenerative disease without markers other than Pick cells, Pick bodies or ubiquitin-labelled non argyrophilic inclusions. We propose the following steps to diagnose the degenerative dementia associated with symptoms and signs of the frontal type: 1. If there is severe frontotemporal atrophy, severe neuronal loss and astrogliosis, many ballooned neurons and characteristic inclusions that are both tau and ubiquitin positive, the diagnosis is Pick disease. 2. If signs of motor involvement (sometimes unnoticed by the clinician) are present with mild cortical atrophy and mild spongiosis of layers II-III, the diagnosis of frontal lobe degeneration associated with motor neuron disease is warranted. Ubiquitin positive inclusions are useful, but non specific, markers. 3. When there are neither Pick inclusions nor motor neuron disease, the diagnosis may be frontal lobe atrophy lacking distinctive histology.

Occupational environment as risk factor for unemployment in multiple sclerosis

INTRODUCTION

Few studies have examined the factors of occupational environment related to unemployment in multiple sclerosis (MS).

MATERIAL AND METHODS

A case control-study was carried out. Cases were patients unemployed for less than five years before the study (n = 77); controls were patients currently employed (n = 94). The odds ratios of the relationship under study adjusted for sex, age, disease form and educational level, were estimated.

RESULTS

Employment in the public sector, sedentary jobs and possibility of obtaining specific improvements in the work environment were found to be protective factors, while jobs needing force, rigid work schedule, manual precision, frequent moves and a daily work duration over 8 h were found as risk factors. Multivariate analyses showed that the only remaining factors were public sector jobs as protective factor (OR = 0.4), and strenuous work as risk factor (OR = 4.5). Factors were slightly different in male and female patients.

CONCLUSION

This study suggests that simple and early changes in the occupational environment could maintain MS patients at work.

Virological diagnosis of progressive multifocal leukoencephalopathy: detection of JC virus DNA in cerebrospinal fluid and brain tissue of AIDS patients

Cerebrospinal fluid (CSF) from 12 AIDS patients with clinical signs consistent with progressive multifocal leukoencephalopathy (PML) was examined by the polymerase chain reaction (PCR) for the presence of JC virus (JCV). A specific JCV target sequence was amplified in the CSF from 9 of the 12 patients and also in brain tissue from all nine JCV-positive patients. The clinical course, neuroimaging features, and, in four cases, histopathology of brain tissue proved that the nine patients had PML. In the other three patients with central nervous system disorders, the JCV genome was undetectable by PCR and Southern blot analysis in CSF and brain tissue. The clinical course and neuroimaging features ruled out PML in these three patients. Five CSF samples and five brain tissue specimens from 10 PML-free AIDS patients with central nervous system disorders were all negative for the JCV genome by PCR and Southern blot analysis. These results show that detection of JCV in CSF by PCR is a good alternative to brain tissue studies for the virological diagnosis of PML in AIDS patients.

Effects of vigabatrin and of GABA on myelinated rat cerebellar cultures: preliminary data

1. The aim of this study was to evaluate the effect of high concentrations of vigabatrin (gamma-vinyl GABA) and of GABA on myelin of the central nervous system cultures. 2. Explants of rat cerebellum were cultured for 14-19 days in vitro on collagen-coated coverslips in Leighton tubes. They were exposed for up to 14 days to 500 nmol ml-1 vigabatrin or to 1000 nmol ml-1 GABA. 3. Qualitative and quantitative blind examination of living cultures and of Sudan black B-stained slides showed mild toxicity of both drugs for myelinated fibres. No clear-cut differences could be demonstrated between the two compounds, although vigabatrin seemed slightly more toxic than GABA at these doses. 4. In electron microscopy, no patent intramyelinic oedema nor primary demyelination were seen. On the contrary, some degenerating myelinated fibres and astrocytic gliosis were seen in both experimental conditions. The changes involved axons as well as myelin sheaths. 5. The toxicity of GABA and vigabatrin was surprisingly mild in this very sensitive model.

Imaging of human brain lesions with an omega 3 site radioligand

The topography and magnitude of increase in peripheral type benzodiazepine binding sites (omega 3 sites) was investigated autoradiographically in the brains of patients with ischemic cerebrovascular disease, with multiple sclerosis, and with malignant glioma. 3H-PK 11195, a selective omega 3 site ligand, was employed. A manyfold increase in omega 3 site density was observed in all these disease states; this increase reflects macrophage invasion or glial proliferation or both as demonstrated by neuropathological studies carried out in parallel. There was an excellent spatial correlation between increased omega 3 site densities and extent of the lesion histologically. Specifically, an elevated density of omega 3 sites was observed in the plaques of demyelination in multiple sclerosis patients, in the periphery of infarcted zones in stroke patients, and throughout tumor in patients with grade IV astrocytomas. As our approach is applicable to both tomographic (in vivo) and autoradiographic investigations, imaging of omega 3 sites may be considered for the detection and monitoring of the natural evolution of many disorders of the human central nervous system.