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Biomedical subjects

G Chazot

Publications and source records attributed to G Chazot.

At least 109 records · Page 6Linked to original sources
PubMed1984

A chronobiological study of melatonin and cortisol secretion in depressed subjects: plasma melatonin, a biochemical marker in major depression.

The temporal organization of plasma melatonin and cortisol secretion was examined in healthy rested controls and in depressed patients: 11 patients suffering from a primary affective disorder (10 female, 1 male) and 8 male controls were studied over a 24-hr period; blood was collected at 2-hr intervals during the day at 1-hr intervals at night. Plasma melatonin and cortisol levels were determined by radioimmunoassay. In addition, melatonin was determined in plasma sampled at 3 AM in older male controls (n = 8) and in females (n = 10) at ovulation. The controls showed low or undetectable (less than 5 pg/ml) diurnal plasma melatonin levels and a very marked nocturnal rhythm (acrophase: 2.27 AM, mesor: 34.4 pg/ml, amplitude: 58.7 pg/ml). For the three control groups, no significant difference was observed in the nocturnal melatonin peak at 3 AM. The depressed patients also showed a significant melatonin rhythm but with lower amplitude (14.5 pg/ml) and mesor (19.1 pg/ml). The latter rhythm was not significantly phase-advanced with respect to the controls (acrophase at 1.18 and 2.34 AM, respectively). In 9 of the 11 patients, nocturnal melatonin secretion was less marked and frequently associated with hypercortisolemia. An additional episodic melatonin secretion was observed in the late afternoon in only two patients. In depressed patients, there was an increase in the mean cortisol secretion level (mesor at 13.6 micrograms/100 ml against 9.1 micrograms/100 ml in the controls), but the amplitude and the acrophase were not significantly modified. These data are discussed in terms of both the hypothalamus-pituitary-adrenal-epiphysis and aminergic abnormalities.

Adult↗
PubMed1984

[Assay of urinary homovanillic acid by gas phase chromatography with a capillary tube].

A sensitive and specific method for the determination of urinary homovanillic acid by gas chromatography with a capillary silica fused flexible column, WCOT, SE 30 phase, is described. Homovanillyl alcohol is used as internal standard. OH and COOH functions are derivatized in a one step reaction with the mixture heptafluorobutyric anhydride - trifluoroethanol (4:1). A linear response of the detector (FID) is obtained with injected amounts of HVA ranging from 0 to more than 1000 ng (standard injected = 400 ng). The smallest detectable level of HVA is about 1 ng, corresponding to urinary levels near 0.1 mg/24 h, or 0.5 micromole/24 h. Correlations between this method and a fluorimetric determination of HVA are studied. Usual values in normal subjects are given.

Adolescent↗
PubMed1983

[Cataplectic falls disclosing hypercalcemia].

Clinical manifestations of hypercalcaemic encephalopathy were heralded in three patients by isolated cataplexy-like falls without loss of consciousness. In one patient the falls with global hypotonia occurred every 5 to 10 seconds and were unaccompanied by changes in E.E.G. The falls disappeared after hypercalcaemia was corrected by excision of a parathyroid adenoma in two patients and by calcitonin injections in one. For this reason, there is little doubt that they were due to the hypercalcaemia, but their mechanism is poorly understood; it probably involves metabolic disturbances in the reticular systems of the brain stem. The connections between calcium metabolism and neuromediators in the brain stem are discussed.

Adenoma↗
PubMed1983

[Topographic and chemical study of the GABA synthetizing enzyme in Parkinsonian syndromes].

After a classical neuropathological study assessing the diagnosis, the activity of the GABA synthetizing enzyme, glutamate decarboxylase (GAD), was assayed in 6 brain areas, in 8 cases of Parkinson's disease, 2 cases of idiopathic orthostatic hypotension and 9 control cases carefully matched. The activity of GAD is not impaired, as classically believed, in parkinsonian brains, particularly in substantia nigra and pallidum. This preservation would indicate the absence of lesion of GABAergic neurones in Parkinson's disease. In the cases of other Parkinsonian syndromes, the number of cases studied is too limited to allow any generality; but they are, however reported because of their rarity.

Aged↗
PubMed1982

Increase in noradrenaline-synthesizing enzyme activity in medulla oblongata in Parkinson's disease.

Dopamine beta hydroxylase (DBH), The noradrenaline-synthesizing enzyme, and phenyl-ethanolamine-N-methyltransferase (PNMT), the adrenaline-synthesizing enzyme, were assayed in 18 areas of brain stem in eight cases of parkinsonian syndromes and of four age- and postmortem delay-matched controls. Dissection was performed by the "punch" technique and enzyme activities assayed by radiometric methods. No significant change was found for PNMT activity. DBH activity was significantly increased in the A2-C2 area of the medulla oblongata (including the nucleus tractus solitarius) in the cases of Parkinson's disease. The A2-C2 area is known to be implicated in the control of blood pressure in rats. These findings are discussed in relation to orthostatic hypotension and the influence of L-dopa therapy.

Aged↗
PubMed1982

[Primary non-Hodgkin's lymphoma of the brain, sarcoidosis, thyroid cancer and immunity cell deficiency (author's transl)].

A 66-year-old man presented with a primary malignant lymphoma of the cerebellum and brain stem. The lymphoma was of type V (Bryon's classification) with predominant B cells, and was associated, as in previously reported cases, with a peripheral blood T lymphocyte deficiency. This case was unusual, in that autopsy revealed an active multivisceral sarcoidosis (considered as being cured more than 10 years previously), a clear-cell renal adenoma demonstrating nearly all the characteristics of a Grawitz's tumor, and a papillary epithelioma of the thyroid gland. These findings lead to discuss the significance of immuno-surveillance lack in this particular case: was it dependent on the sarcoidosis (during which a reduction in T lymphocytes is known to occur), or was it primary and perhaps genetic, a son of the patient having Hodgkin's disease? Whatever the case may be, the encephalic proliferation of the B lymphocyte clone, the peripheral epitheliomas, the sarcoidosis, and the deficit in T lymphocytes in the peripheral blood constitute a group of factors singularly rich in questions, this being, apparently, the first case of this type reported in the published literature.

Aged↗
PubMed1982

[Silver stain of unconcentrated cerebrospinal fluid. Preliminary results in multiple sclerosis and other neurological diseases].

The authors present a new technique for the analysis of the cerebro spinal fluid (C.S.F.) proteins: silver stain after isoelectric focusing with possibility of immunofixation. This technique is simple and results are obtained after six hours only after sample deposition. If immunofixation is used a further 24 hours washing is necessary. It is highly sensitive and bands containing 25 ng of proteins can be clearly distinguished so that small volumes (10 microl. at mean) of unconcentrated C.S.F. can be used. With this technique abnormal distinct bands of IgG specificity are seen in the majority of central and peripheral nervous system inflammatory disorders. No distribution of these bands, particularly in the more cathodal zone, seems to be specific of any disease including multiple sclerosis (M.S.). The abnormal IgG bands in M.S.C.S.F. seem to have their counterpart in the serum. These results need further verification. The usefulness of this technique for research purposes is stressed. The protein pattern obtained must be interpreted in the light of the concepts of genetic polymorphism, microheterogeneity and heterogeneous mode of antibody production.

Cerebrospinal Fluid Proteins↗
PubMed1981

A sensitive method for characterization of oligoclonal immunoglobulins in unconcentrated cerebrospinal fluid.

Although isoelectric focusing has been used to demonstrate the presence of oligoclonal IgG in the CSF, the technique has not allowed detection of oligoclonal IgG in unconcentrated CSF. A new technique is reported, by which unconcentrated CSF is separated by isoelectric focusing, and the IgG bands are then detected by radioimmunofixation. Samples as small as 20 microliters may be used.

Autoradiography↗
PubMed1981

Treatment of Huntington disease with gamma-acetylenic GABA an irreversible inhibitor of GABA-transaminase: increased CSF GABA and homocarnosine without clinical amelioration.

gamma-Acetylenic GABA (GAG, RMI 71.645), a potent irreversible inhibitor of gamma-aminobutyric acid transaminase, was given orally in various dosage schedules to 14 patients with Huntington disease. The biochemical effects of the drug on cerebrospinal fluid (CSF) concentrations of gamma-aminobutyric acid (GABA) and the GABA-containing dipeptide, homocarnosine, were measured in 10 of 14 patients. Treatment with GAG increased CSF concentrations of GABA and homocarnosine as compared to pretreatment values, suggesting that the drug increased brain GABA concentration. Despite this neurochemical effect, the clinical state was not improved. Except for single seizure episodes in five patients, GAG therapy was well tolerated. These results do not exclude the possibility that agents that augment CNS GABAergic function may prove useful in therapy of Huntington disease.

4-Aminobutyrate Transaminase↗
PubMed1981

[Motor negligence in a case of right thalamic hematoma (author's transl)].

In a patient with left motor negligence CT scan showed a right thalamic hematoma of small size, involving the posterior thalamic region. The clinical picture was pure, including neither marked distal or proximal motor deficiency, nor auditory or visual or somesthetic disorders except sensory extinction. Cortical somesthetic evoked potentials were normal. Motor negligence presented 3 basic elements: 1) lack of spontaneous movements of the left side of the body, particularly of the upper limb; 2) absence of nociceptive reactivity; 3) immediate total reversibility of the disorder following verbal commands. Emphasis is placed on this latter sign which indicates the thalamic origin of the disturbance. Of the various explanations proposed for the disorder the most likely one would appear to be a disorder of a relatively specific activation system of motor activities, a system arising from the posterior thalamic nuclei: 1) pulvinar and laterodorsal nuclei projecting over area 23 (posterior cingulum); 2) intralaminar formations, particularly the lateral superior central nucleus, projecting over area 24 (anterior cingulum). The disturbance in this system, at its thalamic origin, might explain the differences between this motor negligence behaviour and lack of spontaneous motility syndromes resulting from frontal cortical lesions. It might also be that the right lateralisation of the lesion plays a relatively minor role.

Diagnosis, Differential↗
PubMed1981

[Effects of physostigmine on amnesic syndromes (author's transl)].

Eserine sulphate (physostigmine) tests were conducted in 23 patients with amnesia due to cerebral lesions. Psychometric examinations were performed before and after treatment. Results were analysed statistically for the whole group, and after distribution of patients as a function of the etiology, of the mechanism involved, and of the presumed lesions: 1) amnesias related to lesions along Papez' circuit as shown on CT scans were compared with those with normal CT scans; 2) amnesias of the "hippocampic" types were compared with other neuropsychological types. After eserine sulphate learning ability rapidly improved, in all cases, whereas spontaneous or assisted recall was only slightly improved. No significant differences in learning or recall were noted between the group with normal CT scans and that with evidence of bilateral lesions. In contrast, the efficiency of physostigmine was clearly related to the nature of neuropsychological disorders both for learning and recall of verbal material : a positive effect occurred only in the group with obvious evocation and recall disorders (mamillary, thalamic, or cingular lesions). For improvement to occur the product had be be injected before learning. The role of cholinergic mediators in memory is discussed with regard to these observations. Overall benefit was poor since lasting improvement in fixation was noted in one case only. Thus eserine sulphate appears of little value for prolonged therapy. It may be useful for a functional test during neuropsychological investigations.

Adult↗
PubMed1980

[Radioimmunofixation: a new technic for characterizing immunoglobulins in unconcentrated cerebrospinal fluid. Preliminary results].

The restriction of heterogenicity of immunoglobulins G (IgG), or oligoclonal distribution, in the cerebrospinal fluid (CSF) can be observed after electrophoresis or electrofocalization, the IgG nature of each oligoclonal band being confirmed by subsequent immuno-electrophoresis. Using immunofixation, the oligoclonal bands can be visualized and characterized simultaneously, but requires previous concentration of the CSF, which is a source of error. The technique of radioimmunofixation, here described, allows the study of IgG with 20 microliters of non-concentrated CSF. It demonstrates that the oligoclonal characteristic is present in normal CSF and is a more quantitative than qualitative feature. Preliminary results show that the method can be applied to the study of all CSF proteins. By using a viral antigen labelled with I-125, for example, it should be possible to reveal and visualize the antibody activity of each oligoclonal band and to determine whether the quantitative increase in an oligoclonal band corresponds to a definite antigenic stimulation.

Humans↗
PubMed1979

[Adrenomyeloneuropathy: an adult form of adrenoleukodystrophy spastic paraparesis, and chronic adrenal insufficiency (concerning 3 cases) (author's transl)].

Three cases of adult males with spastic paraparesis and adrenal insufficiency are reported. The adrenal insufficiency is primary and in one case associated with Leydig cell insufficiency. Ultrastructural examination of peripheral nerve revealed abnormal cytoplasmic inclusions in Schwann cells. A decrease in the percentage of linoleate to total fatty acids was found in the sera. A child with adrenoleucodystrophy and an adult with adreno myeloneuropathy were observed in the same family. It allows adrenomyeloneuropathy to be considered as an adult form of adrenoleucodystrophy.

Addison Disease↗
PubMed1979

[Subacute sclerosing panencephalitis. A case with a prolonged course in an adult. Isolation and characteristics of a "defective" measles virus (author's transl)].

A 33-year-old man had a 6-year history of clinical signs suggesting multiple sclerosis : visual lesion at 27 years of age, cerebellar and visual disturbances at 31, which partly regressed, lymphocytosis and increased-gammaglobulin levels in the cerebrospinal fluid. Biological and anatomical (optical and ultrastructural) examinations gave results typical of a subacute sclerosing panencephalitis. A cytopathogenic measles virus was isolated from a cerebral biopsy specimen. The agent was transmissable to vero cells by co-culture but infectivity was always related to the cells and was therefore an incomplete viral infection. Virus-like particles were found in the nucleus and cytoplasm after electron microscopy examination of the co-cultures. Biochemical tests demonstrated that the viral proteins were all synthesized except hemagglutinin, which is a characterist abnormality of a "defective" measles virus.

Adult↗
PubMed1978

[The neuropathies of monoclonal gammapathies. Immunofluorescence and immunolabelling in the electron microscopy of immunoglobulins with amyloid structure (author's transl)].

Five cases of peripheral neuropathies occurring with monoclonal gammapathies are studied by means of nerve biopsies. Immunofluorescence and HRP-immunolabelling with the electron microscope are performed. The direct pathogenic role of a subperineurial immunoglobulin deposit is pointed out. The relationship of the heavy chain monoclonal immunoglobulin with amyloid fibrils is discussed.

Aged↗