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Biomedical subjects

A Lemonnier

Publications and source records attributed to A Lemonnier.

At least 19 recordsLinked to original sources
PubMed1992

Amino acid transport systems in the human hepatoma cell line Hep G2.

The human hepatoma cell line Hep G2 was used to investigate amino acid transport systems in human liver tissue. The ubiquitous transport systems responsible for the uptake of most neutral amino acids (systems A, ASC and L) were found to be present. Transport system A was predominant for proline uptake but system ASC was the major Na(+)-dependent transport system, particularly for glutamine. The specific hepatic system N was functional, but only partially mediated glutamine uptake. The study of Na(+)-independent arginine uptake demonstrated the presence of the cationic transport system Y+, reflecting the transformed nature of Hep G2 cells.

Alanine↗
PubMed1992

Only prolidase I activity is present in human plasma.

1. After ion exchange chromatographic separation, liver prolidase exhibits two isoforms (prolidase I and II). 2. The activity of both was explored in human and rat tissues, and in normal and cytolytic human plasma. 3. The activity of prolidase I, eluted at the lowest ionic strength, was stimulated by 24 hr of preincubation with 1 mM MnCl2, but prolidase II activity was strongly inhibited by this long preincubation. In both normal and cytolytic human plasma, chromatographic separation also disclosed that only prolidase I activity was present. 4. This isoform displayed properties resembling those of liver and kidney prolidase I. 5. To explain the absence of prolidase II activity from the plasma, we tested the possibility that its tissue distribution differed. 6. However, this was not substantiated by the distribution found, or by the location, molecular weight and behavior of human liver prolidase II after neuraminidase treatment. 7. We also explored the hypothesis that plasma proteins inhibit prolidase II activity, and found that albumin almost abolished this activity after 6 hr incubation.

Animals↗
PubMed1991

Biochemical diagnosis of hepatic glycogen storage diseases: 20 years French experience.

French experience of 242 cases of liver glycogenoses is reported. Screening tests based on serum biochemical data and glucagon tolerance tests are briefly reviewed. The diagnosis of types I glycogen storage disease (GSD) was ascertained in 73 patients' liver biopsies by measurement of glycogen content and by studying the glucose-6-phosphatase system. Liver biopsies were also required at the beginning for the diagnosis of other hepatic GSDs; later on, the possibilities of diagnosis using peripheral blood cells were investigated. Eighty-four cases of type III GSD were confirmed by measurement of debranching enzyme activity and glycogen content using either liver biopsies (78 cases) and/or erythrocytes (37 cases); enzyme determination was also performed in leukocytes and/or fibroblasts for 18 patients. Twenty-four cases of type VI GSD underwent liver biopsies, and the diagnosis could be confirmed using mononuclear or polymorphonuclear cells for 11 of these patients. Sixty-one patients were identified as type IX GSD; phosphorylase kinase deficiency was demonstrated in erythrocytes for all patients, and a liver biopsy was analyzed for 26 of these cases. From this experience, the possibilities of diagnosis of liver GSD using peripheral blood cells are emphasized.

Blood Chemical Analysis↗
PubMed1991

Diagnostic value of serum gamma-glutamyl transpeptidase activity in liver diseases in children.

The clinical usefulness of serum gamma-glutamyl transpeptidase (gamma GT) assay for the diagnosis of liver disease in children was assessed retrospectively in 398 children investigated from 1981 to 1986, in whom diagnosis was ascertained according to currently accepted criteria including liver histology in each case. Serum gamma GT activity was within normal limits in 10 controls, in 19 children with portal vein obstruction, and in 10 of 12 children with congenital hepatic fibrosis. Serum gamma GT was raised in all children with biliary atresia, sclerosing cholangitis, paucity of interlobular bile ducts, and alpha 1-antitrypsin deficiency with jaundice. Serum gamma GT was normal in spite of patent clinical signs of cholestasis in 3 patients with benign recurrent intrahepatic cholestasis, 1 infant with post-hemolytic neonatal cholestasis, and in 22 of 28 patients with progressive idiopathic cholestasis akin to Byler disease. In the latter group, children with raised serum gamma GT displayed extensive portal fibrosis and bile duct proliferation on liver histology, while this was not a prominent feature in children with normal serum gamma GT. These results indicate (a) the value and limits of the assay for serum gamma GT activity in children with liver disease, (b) that raised serum gamma GT may be considered a fairly reliable index of bile duct damage, and (c) that serum gamma GT may prove a useful tool in separating two forms of progressive idiopathic cholestasis, with or without bile duct involvement.

Adolescent↗
PubMed1991

Improved fluorometric determination of malonaldehyde.

Lipoperoxidation is implicated in various pathological conditions. Malonaldehyde (MDA) is the most commonly used marker of this process. We propose simple modifications to Yagi's fluorometric assay for MDA determinations, to avoid long and tedious manipulations by eliminating the first precipitation and washing steps, analogous to HPLC methods, and to increase both the sensitivity and the specificity of the assay by measuring synchronous fluorescence. The proposed technique is easier, faster, and more sensitive than Yagi's method (Academic Press, 1982: Lipid peroxides in biology and medicine). The results obtained with the novel method correlate with those from the HPLC method described by Therasse and Lemonnier (J Chromatogr Biomed Appl 1987;413:237-41).

Chromatography, High Pressure Liquid↗
PubMed1990

Culture of galactosaemic fibroblasts in the presence of galactose: effect of inosine.

Fibroblasts from three galactosaemics had no galactose-1-phosphate uridyltransferase (GALT) activity. These fibroblasts cells were cultured in different media supplemented with dialysed fetal calf serum. Galactosaemic and control cell strains stopped growing in hexose-free medium. In glucose-free medium containing galactose, galatosaemic cells, in contrast to control cells, stopped growing after two days and died. In the same medium supplemented with inosine, they exhibited the same growth pattern as the control cell strains although in the presence of high concentrations of galactose-1-phosphate (Gal-1-P). These findings indicated that the glucose-free medium containing galactose supplemented with dialysed fetal calf serum and inosine, as a ribose donor, was appropriate for further in vitro investigations of galactose metabolism in galactosaemic cells.

Cell Division↗
PubMed1990

Effect of vitamin E on 2-deoxy-D-glucose uptake in human fibroblast cultures.

2-Deoxy-D-glucose (2-DOG) uptake was tested in human fibroblast cultures in the presence and absence of vitamin E. Addition of 10 micrograms/ml vitamin E to the culture medium significantly reduced this uptake for 2-DOG concentrations of 0.005 to 10 mmol/liter (P less than or equal to 0.01). The decrease of 2-DOG uptake was inversely proportional to the rise in 2-DOG concentration (P less than or equal to 0.01). The presence of vitamin E reduced by 71% the average cellular level of lipid peroxides (expressed as thiobarbituric acid reactive substances) and caused a small but significant decrease in the cholesterol concentration (P less than or equal to 0.01). These last results might explain the decrease in 2-DOG uptake observed in the presence of vitamin E.

Biological Transport↗
PubMed1989

Simultaneous determination of hemoglobin and coproporphyrin by second derivative differential spectrophotometry: application to the diagnosis of meconium aspiration.

We describe a simple, fast method for simultaneous measurement of hemoglobin and coproporphyrin in urine and amniotic fluid, by second-derivative differential spectrophotometry. Both pigments were determined in biological samples without prior extraction. Despite the slightly overlapping spectra, the method permitted satisfactory resolution and avoided interspectral interference. Its sensitivity, sufficiently good, allowed to detect hemoglobin and coproporphyrin in slightly pathological urine and amniotic fluid as an aid to the diagnosis of meconium aspiration.

Amniotic Fluid↗
PubMed1989

Cytosolic thymidine kinase activity in cultured human fibroblasts from individuals with galactokinase deficiency.

The structural genes for human galactokinase (GALK) and the human cytosolic form of thymidine kinase (TK1) are located on 17q21-q22. These two loci are tightly linked, and studies on Chinese hamster cell lines have shown that the expression of TK1 and GALK genes may alter simultaneously. We investigated the possibility of a dependent mutation of TK1 and GALK genes in cultured fibroblasts, obtained from two patients homozygous for the GALKG-deficient gene. Since we showed that the TK1 level varies as a function of the passage and the growth rate of a given strain, our experiments were performed on nonstored skin fibroblasts, between the third and the fifth passage for both controls and patients. We found that TK1 levels in GALK-deficient cells were almost 75% of those observed in control strains with a similar growth rate. Previous results in the literature have shown a pronounced decrease in TK1 activity in three GALK-deficient fibroblastic strains. We suggest that these disparities of TK1 levels in GALK-deficient fibroblasts may be related either to genetic heterogeneity of GALK deficiency or to differences in culture conditions.

Cell Division↗
PubMed1989

High hepatic gamma-glutamyltransferase (gamma-GT) activity with normal serum gamma-GT in children with progressive idiopathic cholestasis.

gamma-Glutamyl transferase (gamma-GT) was assayed in the serum and liver biopsies of children affected with either progressive idiopathic cholestasis (PIC, Byler's disease), or other types of cholestatic (biliary atresia, cholestasis of various origins) and non-cholestatic diseases. The mean liver gamma-GT activity was increased significantly only in PIC and biliary atresia. In contrast, the serum gamma-GT activity, raised in children with evident damage to the main bile ducts or to the interlobular bile ducts, was normal in children with PIC. Although the mechanism for such a discrepancy between high liver and normal serum gamma-GT activities in PIC is still speculative, this peculiarity could prove to be of use in leading to a better understanding of the disease.

Biliary Atresia↗
PubMed1989

[Metabolic cooperation in cocultures of fibroblasts from patients with various abnormalities of galactose metabolism].

14C galactose incorporation into the TCA-precipitable material of cultures of fibroblasts deficient in galactokinase (GALK-) was nil. In cultures of fibroblasts deficient in uridyltransferase (GALT-), it was 30 to 75% of control incorporation. In cocultures of GALK and GALT-deficient fibroblasts, 14C incorporation was restored to near-normal levels. This restoration produced in the presence of close cellular contacts was not increased by polyethyleneglycol somatic hybridization. Our results indicate that metabolic cooperation occurred involving the transfer of galactose 1-phosphate from the GALT-deficient to the GALK-deficient cells via intercellular connections.

Carbohydrate Metabolism, Inborn Errors↗