Search PubMed⌕ Search

Biomedical subjects

C Geny

Publications and source records attributed to C Geny.

At least 19 recordsLinked to original sources
PubMed1998

Improvement of action tremor by chronic cortical stimulation.

The authors present a patient who had long-term improvement of a severe upper limb action tremor after chronic cortical stimulation. A 40-year-old woman complained of facial pain and tremor of the left arm after removal of an acoustic neurinoma. A motor cortex stimulation was performed to treat the deafferentation facial pain in 1993. Chronic cortical stimulation induced complete relief of both pain and tremor and allowed the patient to recover functional capacity of the limb. These effects persisted throughout a 32-month follow up. Differential effects on pain and tremor were observed when parameters of stimulation were varied, suggesting different mechanisms for the relief of pain and tremor. Attention was focused on control of the tremor. This effect could be the result of the inhibition of subcortical structures which are involved in tremor. Chronic cortical stimulation appears to be an effective treatment for controlling severe action tremors.

Activities of Daily Living↗
PubMed1997

Gliotoxicity, reverse transcriptase activity and retroviral RNA in monocyte/macrophage culture supernatants from patients with multiple sclerosis.

In investigating a possible link between a novel retroviral agent (provisionally called MSRV), recently characterised in multiple sclerosis (MS), and the neuropathology of MS, it was found that there was a significant correlation between gliotoxicity and reverse transcriptase activity in monocyte/macrophage culture supernatants (MMCS) unique to MS patients. MMCS from healthy controls and patients with other neurological diseases did not display either gliotoxicity or reverse transcriptase activity. The observed gliotoxic effect was an initial, intermediate filament network disorganization and subsequent cell death which was specific to astrocytes and oligodendrocytes. The reverse transcriptase activity and MSRV-specific RNA were observed during the first 2 weeks of culture in MMCS from patients with active MS. The further elucidation of the molecular form(s) of this gliotoxic factor and its original source may be crucial in elucidating important etiopathogenic mechanisms in MS.

Animals↗
PubMed1997

Expression of endogenous retroviruses in blood mononuclear cells and brain tissue from multiple sclerosis patients.

OBJECTIVES: To compare the expression of endogenous retroviruses in MS patients and controls. MATERIAL AND METHODS: Peripheral blood mononuclear cells were obtained from 22 MS patients, a corresponding number of matched healthy donors and five patients with other central nervous system disease. Also brain specimens from MS patients and controls were obtained. Transcripts of various endogenous retroviruses in these samples were detected by RNA-PCR. RESULTS: Several endogenous retroviral sequences were transcribed in peripheral blood mononuclear cells and brain tissue from MS patients as well as controls. A composite transcript of an endogenous retrovirus and a zinc finger sequence was more frequently found in healthy donors than in MS patients. CONCLUSION: Some endogenous retroviruses are normally transcribed in white blood cells and brain tissue. The significance of those findings, which concerned the composite transcripts of the zinc finger sequence and its associated endogenous retrovirus is uncertain.

Adult↗
PubMed1996

Improvement of severe postural cerebellar tremor in multiple sclerosis by chronic thalamic stimulation.

Tremor can be particularly disabling in patients with multiple sclerosis (MS) and is mildly improved by drug treatment. The efficiency of stereotactic thalamotomy has been reported in a small number of patients but was counterbalanced by severe postoperative complications. Stimulation of the thalamic ventral intermediate nucleus, which is a less aggressive surgical method, is efficient in essential and in parkinsonian tremors. We report here the results of thalamic stimulation in 13 patients with MS with tremor. All patients were subjected to clinical examination, videorecording, and quantification of the functional disability before surgery and 3 months postoperatively. The surgical intervention was well tolerated in all cases. A clear improvement of the tremor was observed in 69.2% of the patients. Functional improvement was more varied and depended on the severity of tremor and coexistence of other neurological symptoms. Of the eight most severely affected patients, seven recovered the possibility to easily catch an object and use it. The results indicate that thalamic stimulation may be useful in the treatment of severe postural cerebellar tremor in MS.

Adult↗
PubMed1996

Long-term outcome of unilaterally transplanted parkinsonian patients. I. Clinical approach.

Five patients with Parkinson's disease, unilaterally transplanted with foetal mesencephalic cells into putamen (n=1) or putamen and caudate (n=4), were followed throughout a period of 15-36 months after surgery, according to the recommendations of the core assessment programme for intracerebral transplantations (CAPIT). All these patients exhibited an increase in the fluorodopa uptake in the grafted putamen, which was most significant in the first and last patient of the series. Long-term bilateral improvement of skilled hand movements was observed, starting between the third and sixth month after grafting, and confirmed by the statistical analysis of CAPIT timed tests. A mild to moderate effect on the amount of 'off' time and 'on-off' fluctuations was observed, whereas, apart from one case, no other clear effect on gait, walking and speech was found. One patient included in the study, already suffering slight cognitive impairment, clearly exhibited progression of a dementia process after surgery. Daily living activities were clearly improved in only one of the other four patients. At the end of the study period, all patients needed L-dopa therapy at a similar or higher dose than before grafting, but, in most of them, other dopaminergic drugs were reduced or stopped. All patients exhibited bilateral dyskinesias before grafting that were greatly decreased in intensity a few months after surgery. Delayed asymmetrical dyskinesias, occurring on the side displaying the better motor improvement, i.e. contralateral to the graft, were observed in three patients. These results suggest that neural transplants may influence two central mechanisms involved in motor function and the onset of dyskinesias. These effects are likely to occur through complex interactions with the post-synaptic dopaminergic receptors. The occurrence of dyskinesias might simply reflect increased presynaptic storage and release of dopamine. Alternatively, it might, in part, represent some other long-term deleterious effect of the graft. Since PET-scan data indicate that the reinnervation obtained is sub-optimal, it will be of interest to obtain a larger and denser reinnervation of the host striatum and to try, thereafter, to reduce the dose of L-dopa.

Aged↗
PubMed1996

[Neuropsychological testing of 5 patients with Parkinson's disease before and after neuron graft].

Five patients with idiopathic PD were followed by neuropsychological tests after brain fetal neuronal transplantation. The following tests were used in order to assess memory as well as visuospatial and frontal functions: MMSE, Mattis Scale, Wisconsin Card Sorting Test, Stroop task, word fluency tasks, 15-objects test, WAIS-R (Digit span, Arithmetic, Block design, Pictures completion, Pictures arrangement), learning of 15 words of Rey, WMS-R (Logical memory) and Visual memory of L. Israël. The same tests were performed before, then one year following the transplantation. Pooled data did not show any significant difference between pre and post-operative tests. Individual results varied among patients: 2 remained unchanged, 1 had a pathological deterioration which increased after one year, 1 had some frontal symptoms whereas the last patient improved. Our data confirm that this surgical procedure do not induce permanent neuropsychological deficits, but do not indicate at the present time any clear effect of dopamine reinnervation on cognitive functions.

Aged↗
PubMed1995

Microglial chimaerism in human xenografts to the rat brain.

Neural tissue from human fetuses is currently used for intracerebral transplantation to treat patients with Parkinson's disease. The development of the human fetal tissue following grafting has been considered mostly, up to now, from the neuronal point of view in xenografts. Very little is known, in contrast, about nonneuronal, glial, or vascular cells in the grafts. Comparison of the data gathered on the development of grafted human neurons with those obtained in comparable studies using rat transplants has demonstrated species-specific features. We have therefore undertaken a series of studies dealing with nonneuronal cells in human-to-rat transplants to reveal other possible species-specificity of the human tissue. This study has, accordingly, been devoted to the immunohistochemical analysis of microglia of host and donor origins in a human to rat xenograft paradigm allowing clear distinction of the origin of the cells. Human neural tissue was transplanted as a cell suspension into the thalamus of adult rats. Amoeboid human microglia were observed in 1-, 2-, and 3-month-old transplants, but their density, already relatively low at the first stage, decreased further over time. Ramified human microglia were only occasional. In sharp contrast, host rat microglia rapidly invaded the transplant in the absence of any sign of necrosis. The rat cells exhibited first an amoeboid morphology but progressed at the later stages toward a more mature, ramified morphology. These results indicate that donor microglia are quite few in number at first and, at least, do not proliferate actively after transplantation.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1995

Expression of endogenous retroviruses in blood mononuclear cells and brain tissue from multiple sclerosis patients.

The aim of the present study was to examine whether there is an abnormal expression of certain endogenous retroviruses in MS patients. For this purpose samples of peripheral blood mononuclear cells were obtained from 22 MS patients, a corresponding number of age and sex-matched healthy donors and five patients with other diseases affecting the central nervous system. In addition, brain specimens of macroscopic normal white and gray matter from four MS patients and a similar number of controls were included in the study. Using an enzymatic amplification technique, we found expression of the endogenous retroviral sequences, HRES-1, HERV-K10 and ERV3 in most samples of peripheral blood mononuclear cells from MS patients and controls without obvious differences between these two groups. In contrast, composite transcripts of ERV3 and a zinc finger sequence were more frequently detected in healthy donors than in MS patients. At present, the possible significance of this is uncertain. The retroviral element 4-1 was not transcribed or only transcribed at a very low level in peripheral blood cells of controls and MS patients. Transcripts of various endogenous retroviruses were also detected in the brain samples, but a different pattern was not apparent in the MS group as compared with controls. Aspects concerning a possible association between endogenous retroviruses and autoimmunity are considered.

Adult↗
PubMed1994

Bilateral motor improvement and alteration of L-dopa effect in two patients with Parkinson's disease following intrastriatal transplantation of foetal ventral mesencephalon.

Several recent reports have suggested that foetal ventral mesencephalic transplants could alleviate motor symptoms in patients with Parkinson's disease. Expectations of future success must be clarified by precise analysis of the extent and limitation of recovery associated with an assessment of function of the graft using [18F]fluorodopa (18F-dopa) PET. Two patients with idiopathic Parkinson's disease, severely impaired despite optimal medication, have been followed 10 and 17 months after stereotaxic unilateral intrastriatal transplantation of neural cells dissociated from human foetal ventral mesencephalon. Analysis of the clinical evolution complied with the protocol established in the 'Core Assessment Program for Intracerebral Transplantation'. Both patients have benefited from the transplantation in their daily activities and in motor timed tests, although they still exhibit parkinsonian symptoms and require L-dopa therapy. This is associated with a gradual increase in 18F-dopa uptake at the site of grafting. There are two major clinical changes: (i) a bilateral motor improvement for the speed of movements (the quality of movements improved almost exclusively on the side contralateral to the graft); (ii) a change in the outcome of the L-dopa treatment as exemplified by a postoperative transient period of heavy dyskinesias and subsequent additive actions of the two treatments. These results confirm that neural transplantation may be useful for patients with Parkinson's disease. The improvement recorded on the side ipsilateral to the graft does not match that observed on the contralateral side and it is proposed that bilateral transplantation may be necessary. The existence of a transient postoperative period of heavy dyskinesias suggests that the patients may benefit from a controlled decrease of L-dopa intake after grafting.

Adult↗
PubMed1994

Long-term delayed vascularization of human neural transplants to the rat brain.

Human neural transplants are being developed to treat Parkinson's disease. Previous characterization of human transplants focused on neuronal development, while little is known of the interaction between the transplant and its environment, among which blood is of prime importance. We evaluated here the formation of blood vessels in human neural xenografts placed into the brain of rats immunosuppressed with cyclosporin A. Using capillary wall markers, we found that human transplants remain virtually nonvascularized for more than 1 month. Angiogenesis takes place very slowly and the density of blood vessels is still quite poor after 3 months, the fine structure of these capillaries, when they form, is apparently normal. Functional studies indicate that the vascular network formed in the transplant allows blood circulation and exhibits a working barrier to macromolecules. Glucose uptake and consumption and cytochrome oxidase activity are almost undetectable up to 3 months after grafting. These results demonstrate that vascularization is much delayed in human xenografts into the rat brain. This delay is likely to be dependent on the maturation of the transplanted tissue. A dedifferentiation of human endothelial cells cotransplanted with neural cells occurs since histochemical and immunocytochemical markers revealing endothelial cells in the human fetus are not present up to 1 month in the transplant. The origin of this phenomenon is a matter of speculation. How neural cells survive and mature in such conditions are issues of prime interest for the future of human neural grafting.

Animals↗
PubMed1993

[Diagnosis of diffuse encephalopathies in adults with HIV infection. 2].

A variety of the central nervous system lesions may cause a diffuse encephalopathy in AIDS patients. Apart from viral encephalitides already described in part one, metabolic encephalopathies are a classical cause of diffuse brain dysfunction and are frequent at the terminal stage of the disease. Atypical forms of some infectious, vascular or tumoural processes which usually determine focal lesions, may cause diffuse encephalopathies. These forms are not exceptional in AIDS. The association in the same patient of lesions due to different agents is the rule. Whereas most of the neurological complications of AIDS occur late in the course of the disease, symptomatic, usually transient encephalopathies have been described in the early stages of HIV infection in rare cases. The authors conclude by proposing a management plan, since therapeutic advances have raised some hopes of improvement and even regression of some of these disorders in a few cases, so that physicians do not systematically give up when an AIDS patient presents with a diffuse encephalopathy.

AIDS-Related Opportunistic Infections↗
PubMed1993

[Diagnosis of diffuse encephalopathies in adults with HIV infection. I].

The diagnostic approach of focal central nervous system lesions in AIDS patients is now well established. In contrast, it is extremely difficult to determine the cause of diffuse encephalopathies, occurring frequently at the terminal stage of AIDS. Imaging is usually non specific and laboratory investigations are seldom contributive. In most cases, the aetiological diagnosis is provided by post mortem examination. In this first part of the study the authors deal with viral encephalitides which represent a classical and frequent cause of diffuse encephalopathy in AIDS. HIV encephalitis usually causes a progressive brain disease resulting in severe dementia; imaging may show diffuse leucoencephalopathy and/or cortico-subcortical atrophy. CMV encephalitis is often asymptomatic, discovered at autopsy; however, this diagnosis should be considered in patients with an encephalopathy of rapid onset, discrete signs of meningitis, symptoms of myelo-radiculitis, or a systemic CMV infection. Varicella-zoster virus encephalitis is not uncommon and may occur in the absence of characteristic rash. Infections by herpes simplex and measles viruses are exceptional.

AIDS Dementia Complex↗
PubMed1993

Acute varicella-zoster virus ventriculitis and meningo-myelo-radiculitis in acquired immunodeficiency syndrome.

A 30-year-old AIDS patient with no history of cutaneous eruption, presented with rapidly progressive flaccid paraplegia, hypoesthesia, urinary retention, moderate psychomotor slowing and fever (39.8 degrees C), leading to death within 1 week. CD4 count was 290/mm3. Cerebrospinal fluid contained 210 white blood cells and 238 mg/100 ml protein. Neuropathology revealed HIV encephalitis and diffuse ventriculitis with Cowdry type A inclusions in the ependymal cells. Extensive necrotic and hemorrhagic changes with marked recrotizing vasculitis involved the entire spinal cord and spinal roots. Immunocytochemistry revealed numerous inclusion bodies positive for varicella-zoster virus (VZV) and negative for cytomegalovirus (CMV) and herpes simplex virus type 1 and 2, in ependymal cells, subpial glial cells, endothelial cells and Schwann cells. Electron microscopy confirmed herpes virus-like particles. In situ hybridization confirmed VZV genome in leptomeninges, brain, spinal cord and spinal roots. Comparable neuropathological findings and numerous VZV inclusion bodies were also found in the brain, spinal cord, and spinal roots of a 40-year-old AIDS patient who died from a fulminant ascending myeloradiculopathy previously reported as "necrotizing vasculitis of the nervous system". Direct infection of the brain by VZV, in AIDS patients, has been shown to cause leukoencephalitis and cerebral non-inflammatory vasculopathies. Our observations demonstrate that, in AIDS patients, VZV infection of the central nervous system may also be responsible for meningo-myelo-radiculitis possibly secondary to ventriculitis as in CMV infection. The role of VZV in the pathogenesis of some AIDS-related vasculitides seems also very likely.

AIDS Dementia Complex↗
PubMed1993

Pseudotumoral neuro-Behçet's disease.

Pseudotumoral presentation of Neuro-Behçet's disease has been described before. The diagnosis may be difficult obtain in patients without mucosal, cutaneous, and ocular signs. We report the observation of a young patient suffering from a right hemiparesis with computed-tomographic (CT) features suggestive of a thalamocapsular expanding lesion. Histologic study of brain biopsy tissue ruled out a tumor but did not show any specific diagnosis. The patient improved with steroid therapy.

Adult↗
PubMed1992

Hypothermia, Wernicke encephalopathy and multiple sclerosis.

Neurological exacerbation observed in MS patients is usually related to a demyelinating process. We report two patients where hypothermia (32.4 degrees C and 32.5 degrees C) and neurological exacerbation were probably due to a Wernicke encephalopathy (WE). The clinical features and the rapid efficiency of parenteral thiamine were suggestive of WE. Hypothermia is an exceptional symptom observed in MS and has been considered as resulting from hypothalamic demyelination; these two cases showed that WE which is another cause of reversible hypothermia, can be associated with MS.

Body Temperature Regulation↗
PubMed1992

[AIDS-related progressive multifocal leukoencephalopathy limited to U fibers, responsible for subacute encephalopathy with normal CT scan findings].

A 41-year-old male homosexual with AIDS was hospitalized for temperature elevation to 40 degrees C with confusion. Neurologic evaluation found psychomotor slowing and temporospatial disorientation with no focal signs. The CD4 count was 100/mm3. CSF analysis and the CT scan were normal. Despite antiviral treatment the patient died fifteen days after admission. Gross appearance of the brain was normal. Histologic examination disclosed multiple, small foci of demyelination characteristic of progressive multifocal leukoencephalopathy. These foci were disseminated among the U fibers. In situ hybridization and immunocytochemical studies demonstrated papovavirus particles in oligodendrocytes and a few astrocytes. This case shows that papovavirus infection in AIDS patients may be responsible for a diffuse febrile encephalopathy with normal CT scan findings and a rapidly progressive course.

AIDS-Related Opportunistic Infections↗