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Biomedical subjects

M Clanet

Publications and source records attributed to M Clanet.

At least 91 records · Page 5Linked to original sources
PubMed1989

Abnormal ocular movements in Parkinson's disease. Evidence for involvement of dopaminergic systems.

Quantitated automated electro-oculographic data from 45 parkinsonian patients were compared with those from 30 normal control subjects. Patients were selected with idiopathic Parkinson's disease without other associated neurological disease or dementia; 20 had never received antiparkinsonian drugs and in 25 such treatment had been stopped for at least 2 days. Saccade latency, amplitude and peak velocity, smooth pursuit peak velocity, optokinetic nystagmus (OKN) maximal and mean velocities and vestibulo-ocular reflex (VOR) suppression by vision or imagination were significantly altered in patients, whereas VOR gain in darkness was normal. Alterations of saccade latency and smooth pursuit peak velocity were more severe in the more advanced stages of the disease and saccade latency directed towards the symptomatic side was slightly delayed in hemiparkinsonian patients. Saccade amplitude improved 90 min after a single oral dose of L-DOPA. These results suggest a possible dopaminergic control of some ocular movements.

Adult↗
PubMed1989

Calcium antagonists and the vestibular system: a critical review of flunarizine as an antivertigo drug.

Flunarizine, a diphenylalkylamine, is one of the most popular antivertiginous drugs used nowadays in France. However, until now, there are very few preliminary data about the physiological or pathophysiological functions of calcium in the vestibular system. Moreover, experimental and clinical arguments are still insufficient to clearly demonstrate that 1) flunarizine is an effective antivertiginous drug and 2) this putative antivertiginous property is really due to the anticalcic action of the drug and not to a more classical antagonistic effect on H1 receptors. Much more work is needed before accepting the indication of any anticalcic drug as an effective antivertigo treatment.

Animals↗
PubMed1989

Risk factors in multiple sclerosis: a population-based case-control study in Hautes-Pyrénées, France.

A population-based study of the prevalence and risk factors of multiple sclerosis (MS) was conducted in the Hautes-Pyrénées, the southwestern region of France. The prevalence rate per 100,000 was equal to 40. Data on the past medical history of 63 MS patients and matched controls were collected. The frequency and age at occurrence of common childhood infections were similar for both the MS cases and controls. There was no difference between the frequency of vaccination for MS patients and for controls. However, the age at which MS patients were immunized against poliomyelitis was significantly higher than the corresponding age for controls (15.8 years versus 8.9 years, P less than 0.01). Antibody titers for various viruses were measured. The mumps antibody titer was significantly higher in the MS patients than in the controls. Also, MS patients tended to have higher titers for measles antibodies.

Adult↗
PubMed1989

SPECT study of cerebral blood flow reactivity after acetazolamide in patients with transient ischemic attacks.

We investigated 15 patients with one or more transient ischemic attacks (TIAs) in the internal carotid artery territory within the month following the most recent TIA. Cerebral blood flow (CBF) was measured by single-photon emission computed tomography, using intravenous xenon-133 before and after injection of 1 g acetazolamide. Six patients had severe carotid stenosis or occlusion; the other nine patients had no significant carotid lesions. Twenty age-matched volunteers free of neurologic symptoms or history were used as controls. Mean CBF in the sylvian region was not significantly different between patients and controls. Seven patients exhibited a focal hypoperfusion at rest in the symptomatic hemisphere, and their hypoperfused areas were hyporeactive after administration of acetazolamide. Seven other patients exhibited hyporeactive areas after acetazolamide administration while their CBF tomograms at rest were normal. Thus, CBF abnormalities were detected in 14 of the 15 patients. Our findings suggest that CBF measured early after acetazolamide administration could be useful to confirm the clinical diagnosis of TIA. In the nine patients with no significant lesion of the internal carotid artery, the areas of hypoperfusion were small and were probably related to the focal ischemic event. In the six patients with severe lesions of the internal carotid artery, abnormalities were of variable size and intensity but were often large and pronounced. The discrepancy between these two subgroups of patients could be ascribed to the hemodynamic influence of the internal carotid artery lesions. Moreover, our findings may provide some insight into the pathophysiology of TIAs.

Acetazolamide↗
PubMed1987

[Importance of the study of cerebral blood flow and regional oxygen consumption in cerebral ischemia].

Studies of experimentally-induced ischaemia have shown that the intensity of neuronal suffering is related to the fall in perfusion rate. Below a certain level, called functional threshold, cerebral function is reversibly altered, whereas at a lower level (tissue necrosis threshold) the damage inflicted on neurons is irreversible. Between these two threshold lies a "penumbra zone". This concept of thresholds must be mitigated by 2 parameters: duration of ischaemia and selective vulnerability of the various structures affected. Variations in blood flow rate only indirectly affect the state of tissues. Techniques developed from positron emission tomography make it possible to evaluate the metabolic activity of brain tissue in vivo: oxygen consumption (CMRO2), oxygen extraction (EO2) and glucose consumption (CMRG) which are thus correlated to cerebral blood flow and cerebral blood volume, sometimes also to tissue pH. Normal relations between blood flow rate and metabolism may be altered. Misery perfusion reflects a fall in cerebral blood flow with an increase in EO2 and often a decrease in CMRO2, whereas luxury perfusion reflects an increase in cerebral blood flow rate with reduction of CMRO2, EO2 and CMRG. The type of alteration encountered in human ischaemia varies according to the nature of the accident: studies of transient accidents emphasize the different haemodynamic aspects of occlusion of the wider arteries. The metabolic and haemodynamic profiles of established ischaemic accidents vary according to their type and to the time of the study, reflecting the complexity of the physiopathological mechanisms involved; they are frequently associated with metabolic repercussions at a distance from the ischaemic focus, which supports the concept of diaschisis. Arteriopathic dementia probably does not result from chronic ischaemia of the cerebral parenchyma.

Brain↗
PubMed1987

[Immunogenetics of multiple sclerosis].

The interaction between environmental factors and genetic susceptibility causes multiple sclerosis. In some ethnic groups this disease is rare. The family incidence varies from 6 to 12%. Analysis of twins shows a concordance two fold higher in homozygous twins. The transmission of such a genetic susceptibility cannot be explained by means of an usual genetical model. In Caucasoids, an association exists between MS and HLA A3, B7 and DR2 antigens. However this association is not always found and can be different from one population to another one. The mechanisms of the association are unknown: either the HLA haplotype supports the disease susceptibility but family segregation studies are unconvincing, or this susceptibility is due to the interaction of several genic complexes, a few of which linked to HLA region. An etiological heterogeneity of MS has also been suggested.

Disease Susceptibility↗
PubMed1986

Immunoglobulin allotypes and susceptibility to multiple sclerosis. An epidemiological and genetic study in the Hautes-Pyrénées county of France.

Serum samples collected from 69 patients with multiple sclerosis (MS) living in the Hautes-Pyrénées county were tested for immunoglobulin Gm gamma 1, gamma 2, and gamma 3, heavy chain allotypes (Gm system), and immunoglobulin light chain Kappa (Km system). A control group was made up of normal individuals living in the same county. We found a significant excess of individuals with Gm3; +/- 23;5/Gm3; +/- 23;5 amongst the MS patients as compared with controls (relative risk = 2.4). A slight increase of the Km (1) frequency was found in MS patients compared with controls, 21.7% vs 11.8%, but this difference was not significant.

France↗
PubMed1986

[Double-blind treatment of 49 cases of chronic multiple sclerosis using hyperbaric oxygen].

Forty nine patients with a chronic form of multiple sclerosis (MS) [progressive or stable] were treated with hyperbaric oxygen (HO) in a double blind trial. Patients were divided in three groups: the first group (group I) received a course of 2.3 ATA HO with diazepam (5 mg); the second group (group II) received a course of 2 ATA HO; the third group (group III) was the control group. Each patient breathed an adapted gaseous mixture in high pressure. Each patient received 20 sessions of this procedure during 4 weeks. Patients were evaluated with clinical, neurophysiological and immunological parameters. Clinical examination consisted in the evaluation of the Kurtzke's Disability Status Scale (DSS) and Functional Status Scale (FSS). This evaluation was done in the week before the procedure, the week following the treatment, then in the third and sixth month. The neurophysiological study was a comparative analysis from the variations of visual, somesthesic and brain stem auditory potentials. The immunological study was the analysis of the lymphocyte populations (OKT4/OKT8 ratio). Each examination was carried out the week before, then the week following the procedure. We found no amelioration into three groups. Subjectively, some patients thought to be better, but this was true in the two treated groups (I, II) and in the control group (III). There was not an FSS significant variation. We also found no significant variation of evoked potentials and OKT4/OKT8 ratio. We observed some incidental effects of the treatment, particularly in group I, in which patients were treated with a higher pressure.(ABSTRACT TRUNCATED AT 250 WORDS)

Brain↗
PubMed1986

[Analysis of the cerebrospinal fluid by isoelectrofocusing on agarose in multiple sclerosis].

Intrathecal synthesis of immunoglobulins can be proved by means of two methods: quantitatively by immunoglobulins titration in CSF, the results expressed with several ratios; qualitatively by demonstration of oligoclonal distribution of gammaglobulins. IEF is the most sensitive of the qualitative methods. From a technical point of view Agarose Isoelectrofocusing seems to be a better method than polyacrylamide isoelectrofocusing and permits, when the interpretation is difficult, immunofixation into the gel. The authors report the results of a comparative study between the evaluation of the IgG Index and agarose isoelectrofocusing of 281 CSF divided into 113 CSF from patients with Multiple Sclerosis (MS) and 168 CSF from patients with other neurological diseases (OND). Sensitivity of IEF was higher than IgG index to prove intrathecal IgG synthesis: in the group of patients with MS, 91 p. 100 of CSF were abnormal instead of 72 p. 100 of IgG Index. In the group of patients with OND, abnormalities in IEF were low (5 p. 100) but the number of inflammatory diseases was poor. These results were similar with the findings of many authors using the same methods. In our opinion, IEF is the best technique which a specialized laboratory can use in routine to prove an immunoglobulin intrathecal synthesis.

Central Nervous System↗