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Biomedical subjects

G Renaud

Publications and source records attributed to G Renaud.

At least 37 records · Page 2Linked to original sources

Ethmozine for ventricular premature complexes.

Twenty patients with an average of more than 30 ventricular premature complexes (VPCs) per hour were treated with ethmozine. Eighteen had either not responded or had adverse reactions to at least 1 other antiarrhythmic drug. Patients were treated with 200 to 300 mg 3 times daily (8.25 to 11.7 mg/kg) and were followed for up to 6 months. Three patients were withdrawn from ethmozine therapy because of unwanted effects before evaluation of efficacy. One of these patients had sustained ventricular tachycardia (VT) after a loading dose of ethmozine. Eleven of the remaining 17 patients (65%) experienced more than a 75% reduction in ventricular ectopic activity. Six patients had a smaller or no decrease in VPC frequency. Eleven of 16 patients (68%) with paired VPCs had a more than 90% reduction in paired VPC frequency. Eleven of 13 patients (84%) with VT events of 3 beats or more had more than a 90% reduction in VT events. Of the 11 patients in whom a more than 75% reduction in VPC frequency occurred, 1 patient died suddenly after 133 days of effective drug therapy. Three patients discontinued ethmozine therapy for reasons not related to the drug. Of the 6 patients in whom there was less than a 75% reduction in VPC frequency, 2 patients discontinued treatment, 1 patient because of hyperanxiety and 1 because of drug-related left anterior hemiblock. Ethmozine lengthened PR and QRS intervals but not the JT interval. Thus, ethmozine is effective and clinically useful for suppression of frequency VPCs in 50% (10 of 20 patients) of a selected population.

Aged↗

[AIDS mortality in France].

A study about mortality by AIDS had been undertaken since July 1st 1983, in the Service of Information on Medical causes of Death (INSERM SC8), which is in charge of developing mortality statistics in France. From July 1st 1983 to September 30th 1985, 243 deaths due to AIDS were recorded. Only the cases where this diagnosis was clearly mentioned were selected; more than 90% were notified by hospitals and mainly by highly specialized services. The number of deaths, which was low and varied rather irregularly at the beginning, then increased by successive stages. The first year, during which a tenth of deaths was recorded every three months, was followed by a great increase, doubling, then tripling the initial numbers. Lastly, a second and sudden rise occurred during the third trimester of 1985, the trimestrial number of deaths due to AIDS reaching 80.

Acquired Immunodeficiency Syndrome↗

Isolation of rat hepatocytes with EDTA and their metabolic functions in primary culture.

Isolated hepatocytes from adult rat liver were prepared after dissociation of the liver with EDTA. The morphological appearance, viability (94.5%) and yield (1.76.10(7) cells/g liver) compare well with those of previously described methods using collagenase. Differentiated functions of the hepatocytes in primary culture such as albumin secretion (10.9 micrograms/mg cell protein/d) and triglyceride synthesis and secretion are maintained. Induction of triglyceride synthesis and secretion by oleic acid takes place to an extent similar to that observed in vivo and liver perfusion. Particles with a lipid composition resembling circulating very low density lipoproteins are secreted into the medium. These characteristics demonstrate the ability of hepatocytes isolated with EDTA and subsequently used in primary culture to retain complex and highly differentiated functions of the intact liver.

Albumins↗

Free fatty-acid uptake by isolated rat hepatocytes.

In isolated rat hepatocytes, the rate of palmitic acid binding and uptake is directly related to the concentration of free fatty acid (FFA) in the medium. After their entry into the cell, FFA are immediately incorporated into cellular phospholipids and triglycerides and no accumulation of free fatty acids can be demonstrated inside the cell. The rate of free fatty-acid uptake remains unchanged after incubation in a 2 mM KCN containing medium, indicating that in the range of fatty-acid concentrations used in this study, this phenomenon does not require energy.

Animals↗

Effect of chloroquine on low-density lipoprotein catabolic pathway in rat hepatocytes.

Injection of 125I-low-density lipoprotein (LDL) into estradiol-treated rats substantially increases the volume of the multivesicular body compartment in hepatocytes. When these animals were additionally given chloroquine 60 and 120 min before injection of 125I-LDL, the amount of 125I retained by the liver increased threefold and the amount of label in multivesicular bodies increased fivefold, as determined by quantitative analysis of autoradiograms. Lamellar inclusions that appeared after chloroquine also contained a substantial fraction of 125I, whereas the fraction of 125I in secondary lysosomes was reduced. From these data it is concluded that the multivesicular bodies comprise an intermediate endocytic compartment, the conversion of which to secondary lysosomes is impeded by chloroquine.

Animals↗

Impaired receptor-mediated catabolism of low density lipoproteins in fasted rabbits.

Plasma cholesterol levels of New Zealand white rabbits, fasted for 9 days, increased 4-fold owing to elevated levels of low density lipoproteins and intermediate density lipoproteins. Estimates of the turnover of radioiodinated low density lipoproteins and methyl-low density lipoproteins using the Matthews model showed that clearance of low density lipoprotein by receptor-dependent pathways was reduced by 80%. Receptor-independent removal of low density lipoprotein was unchanged. The absolute catabolic rate of low density lipoprotein was not affected by fasting. EDTA-sensitive binding of 125I-labeled low density lipoproteins was selectively lost from liver membranes isolated from fasted rabbits. These results are consistent with the hypothesis that the hypercholesterolemia of fasted rabbits is the result of down-regulation of the hepatic low density lipoprotein receptor.

Animals↗

Uptake and processing of remnants of chylomicrons and very low density lipoproteins by rat liver.

In the rat, chylomicron remnants and very low density lipoprotein (VLDL) remnants are taken up into the liver by high affinity processes and appear to undergo degradation by lysosomes. The relationship of this catabolic process to the known pathways of uptake and degradation of low density lipoproteins (LDL) and the involvement of nonparenchymal cells are addressed in these studies. We have utilized both light and electron microscopic radioautography to determine whether the pathway of intracellular transport and catabolism resembles that established for LDL in hepatocytes. Radioiodinated plasma VLDL remnants and lymph chylomicron remnants were injected into femoral veins of rats and the livers were fixed by perfusion 3 to 30 minutes later. Quantitative light microscopic radioautography showed little or no accumulation of grains over Kupffer cells. Electromicroscopic radioautography confirmed these observations and, in addition, demonstrated that very few grains were associated with endothelial cells. The processing of the remnant particles closely resembled that of LDL. Following an initial association of grains with the parenchymal cell plasma membrane, frequently in regions in close proximity to clathrin-coated endocytic pits, the grains were found in endocytic vesicles just beneath the plasma membrane. By 15 minutes the grains were found over multivesicular bodies located in the Golgi-lysosome region of the cell. Thirty minutes after injection, radioautographic grains began to be associated with secondary lysosomes. These data indicate no significant role for nonparenchymal cells in the internalization and subsequent degradation of triglyceride-rich lipoproteins, and provide evidence that the processing of remnants as well as LDL follows the classical pathway of receptor-mediated endocytosis.

Animals↗

Effect of clofibrate on the enzyme activity of rat liver plasma membranes.

The activity of 3 plasma membranes marker enzymes (5'-nucleotidase, Mg++-ATPase and alkaline phosphodiesterase-I) was determined in plasma membranes isolated from liver of control and of clofibrate-treated rats. A complete indentity of plasma membranes enzyme activity in the 2 groups of experimental animals was observed for the 3 enzymes studied.

5'-Nucleotidase↗

Effect of acetone on VLDL secretion by the isolated rat liver.

High acetone levels occur in uncontrolled diabetes and after isopropanol administration to rats. In both conditions, very low density lipoproteins (VLDL) secretion is depressed. Acetone, hoever, failed to affect the VLDL secretion rate by the isolated perfused rat liver, suggesting that this metabolite is not involved in impaired VLDL production in diabetes and after isopropanol administration.

Acetone↗

[Action of isopropanol on rat lipid metabolism: complementary studies on mechanisms implicated in hepatic accumulation of triacylglycerides].

Isopropanol administration (3 g/kg, p.o.) determines in the rat liver an inhibition of fatty acid oxidation, an enhancement of fatty acid esterification into triacylglycerols as well as an inhibition of lipoprotein secretion which appears to be related to alterations in hepatic phospholipids and which differentiates isopropanol from ethanol induced fatty liver. Disturbances in peripheral lipolysis following isopropanol administration are found only in mature rats and are not necessary to the fatty liver induction.

1-Propanol↗