Biomedical subjects
C Miquel
Publications and source records attributed to C Miquel.
Determination of retinoid activity by an enzyme-linked immunosorbent assay.
In normal human keratinocytes, retinoic acid suppresses the expression of the plasma membrane associated enzyme transglutaminase (TGm) at the pretranslational level. This finding led us to develop an enzyme-linked immunosorbent assay (ELISA) for the evaluation of the biological activity of retinoids, i.e., natural and synthetic derivatives of vitamin A. In this assay, keratinocytes are cultured in a 96-well cluster in the presence of different retinoid concentrations. The expression of TGm is then quantified, without any extraction or purification step, using a TGm-specific monoclonal antibody and a peroxidase-conjugated secondary antibody. The dose-response curves obtained show this ELISA to be a sensitive and reproducible assay to determine the potency of retinoids.
Deficiency in catalase activity correlates with the appearance of tumor phenotype in human keratinocytes.
Biopsies isolated from various human stratified epitheliomas and cultures of the associated fibroblasts exhibit a breakdown in catalase activity (70 to 95%). We report here that primary human cultures of keratinocytes and various immortalized keratinocyte cell lines differ from one other in their catalase activity. Moreover, deficient catalase activity appears to be related to the intensity of tumor phenotype expression. Since catalase activity in cell lines transformed in vitro is not as weak as activity observed in cell lines isolated from tumors, catalase deficiency may follow the successive steps of tumor progression.
[Calcification of the mitral annulus: clinical and echocardiographic aspects].
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Heart rate variations in the Guillain-Barré syndrome.
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[Hypokalemic periodic paralysis. Report of two cases (author's transl)].
The familial periodic hypokalemic paralysis is an infrequent disease characterized by paralytic attacks of sudden appearance affecting the muscles of the trunk and limbs. There is a marked hypokalemia during the paralytic episodes of the disease, and a family history in 80 percent of the cases. The differential diagnosis includes hyperthyroidism with periodic paralysis, congenital paramyotony and adynamia episodica hereditaria. Two typical cases of hypokalemic periodic paralysis are presented, with biological, electrophysiological, clinical, and ultrastructural pictures characteristics of the disease. The clinical manifestations of both patients are discussed, stressing the diagnostic importance of the electrophysiological study during the insulin test, and the interest of the histologic and ultrastructural studies. The spectacular response during the acute episodes to the intravenous perfusion of potassium salts, and the usefulness of the acetazolamide administration to prevent the paralytic episodes are emphasized.
Spontaneous rupture of the spleen in staphylococcal bacteremia.
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[Noninvasive diagnosis of cardiovascular abnormalities in subclinical Chagas' disease (author's transl)].
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[Etiologic diagnosis of pneumoccocal pneumonia by counterimmunoelectrophoresis (author's transl)].
The antigenic composition of the pneumoccocal capsule and its easy detection by counterimmunoelectrophoresis led us to carry out a comparative study of this method and the results obtained from cultures. A series of 159 patientes with suspected bacterial pneumonia were included in the study. Blood cultures were prepared for all of the patients; sputum cultures were practiced on 35 and cultures of pleural fluid on 32. Serum from all of the patients, urine from 104, sputum from 34, and pleural fluid from 16 were analyzed by counterimmunoelectrophoresis for pneumoccocal antigen. This method was particularly useful for detecting the germ in sputum and pleural fluid. Furthermore, a higher number of positive indexes in serum were obtained by counterimmunoelectrophoresis than by blood cultures (p less than 0.01). This was also true for tests with sputum and pleural fluid. Urine tests resulted in an even greater number of detections. Counterimmunoelectrophoresis is thus a simple, quick method for detecting pneumococcus and is especially useful when accompanied by cultures tests, since they are complementary. We were able to discover a positive indication of penumoccocus in bacterial pneumonia in 39.6 percent of cases with this technique, as opposed to 15 percent using cultures alone.
[Erythroblastopenia associated with tuberculostatic therapy (author's transl)].
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Effects of ethanol-induced hypoglycaemia.
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[Pleural effusion in rheumatoid arthritis].
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Effect of heparin on lecithin: cholesterol acyltransferase and lipids in cholestasis.
The effect of heparin on the proportion of cholesterol esters, lecithin/lysolecithin ratio, and lecithin: cholesterol acyltransferase (LCAT) activity was studied in twelve patients with cholestasis. A good correlation was observed between a decreased LCAT activity and the proportion of cholesterol esters, and no consistent variation was noted after heparin. The lecithin/lysolecithin ratio was increased in 7 patients and became normal after heparin in 6 cases. The clearance of lipoprotein-X after heparin seems to be not related to LCAT activity. These results demonstrate that heparin does not modify the LCAT activity, and suggest that heparin induces an increase of phospholipase activity in some patients with cholestasis.
Action of heparin on lecithin:cholesterol acyltransferase activity in normal subjects.
The triglyceride decrease and free fatty acid increase by lipoproteinlipase post-heparin effect does not modify the Lecithin:Cholesterol Acyltransferase activity in vitro, using homologous substrate, in normal subjects. These findings agree with the unmodified proportion of esterified cholesterol and relative proportion of phospholipids on thin layer chromatographic fractioning after heparin. The conclusion is reached that heparin has no action on Lecithin:Cholesterol Acyltransferase activity in normal subjects.
[Determination of lecithin: cholesterol acyltransferase activity by a radioisotopic assay (author's transl)].
A method for determining Lecithin: Cholesterol Acyltransferase (LCAT) activity is presented. Trace amounts of labelled cholesterol are added to innactivated homologous substrate from a pool of normal serum. LCAT activity is determined measuring the cholesterol esterification, and is expressed as micrograms of cholesterol esters formed per milliliter plasma per hour. LCAT time-course, reproducibility, activity after serum storage at 4 degrees C, and normal values from 20 healthy subjects are studied.
[Primary sarcoma of the gallbladder].
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[Letter: Disorders of circulating lipids in the course of Zieve's syndrome].
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[Propranolol and cardiac insufficiency].
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