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Biomedical subjects

F Sztark

Publications and source records attributed to F Sztark.

43 records · Page 3Linked to original sources
PubMed1992

Is bupivacaine a decoupler, a protonophore or a proton-leak-inducer?

This paper deals with the mechanism of bupivacaine uncoupling of oxidative phosphorylation in rat heart mitochondria. By comparison with the effects of QX 572, a permanently charged quaternary amine-type local anesthetic, it is concluded that the effects of bupivacaine and QX 572 may be explained by classical uncoupling behaviour. In the case of bupivacaine this uncoupling effect is mediated through a protonophore-like mechanism, whereas that of QX 572 is simply explained by an electrophoretic uptake.

Animals↗
PubMed1986

The sinusoidal barrier in alcoholic patients without liver fibrosis. A morphometric study.

Alcohol induces morphological changes in the endothelial and perisinusoidal cells at the fibrotic stage of alcoholic liver diseases. Directly or indirectly, through hemodynamic disturbances linked to the enlargement of steatotic hepatocytes, alcohol may modify this barrier before the onset of fibrosis. Liver biopsies were obtained from control and from alcoholic patients and perfusion-fixed. Volume and surface densities of endothelial cells, perisinusoidal cells and their processes were measured. Liver histology was normal in the 2 groups except for steatosis in the alcoholics. Volume densities represented 8.2%, 4.7% and 3.2% of the sinusoid in controls for endothelial cells, perisinusoidal cells and their processes whereas surface densities represented respectively 0.5, 0.23, 0.21 m2/cm3 of sinusoid. Morphometric values were not significantly different in the alcoholic patients. In none of the alcoholic patients did fine morphological studies of sinusoidal cells give any indication of the possible evolution of the alcoholic disease towards fibrosis. These results indicate that in the group of patients studied, alcohol, before the fibrotic stage, did not significantly alter the sinusoidal barrier.

Adult↗
PubMed1986

Perisinusoidal cells in patients with normal liver histology. A morphometric study.

We measured the number and the morphometric characteristics of perisinusoidal cells in perfusion-fixed biopsy samples from 7 control patients with normal liver histology. On 1-micron section, the number of cells was 18 +/- 1.5/0.1 mm2; 25% of cells did not apparently contain lipids. There were no significant zonal differences. The volume density of the cells represented 1 +/- 0.2% of the hepatic parenchyma. On ultrathin sections, the volume and surface densities of processes were 3.2 +/- 0.7% of sinusoid and 0.21 +/- 0.04 m2/cm3 of sinusoid respectively which represented 70% and 90% of total PSC volume and surface densities. Lipid volume density was 20.5 +/- 7.3% of the nucleated cell. More than 30% of cells contained less than 10% of lipids. There was no correlation between lipid volume density and RER surface density.

Adult↗
PubMed1985

The sinusoidal barrier in rats with portacaval anastomosis: a morphometric study.

Shunting of portal blood in the rat leads to liver atrophy and to an increase in arterial blood flow with microcirculatory disturbances. The aim of this study was to investigate the effects of these disturbances on the liver sinusoidal barrier (endothelial and perisinusoidal cells) using morphometric techniques. Rats with portacaval anastomosis (PCA) and sham operated pair-fed controls were studied 3 months after the shunt. Sinusoidal volume density in PCA increased but not significantly and the volume density (Vv) of total endothelial (EC) and perisinusoidal cells (PSC) increased by 104.54% compared to sham operated pair-fed rats. The increase of EC Vv was not associated with an increase in surface density (Sv) suggesting a fall in the number of small fenestrations and an increase in cell thickness. This interpretation supports the morphological observations. The increase of PSC Vv was mainly related to the increase in their subendothelial processes Vv and not to that of the cell body Vv. Lipids Vv and RER Sv expressed per sinusoidal cells remained unchanged suggesting that the balance between the 2 hypothetical functions of the PSC, namely fibrogenesis and storage of vitamin A, was maintained. In conclusion, changes of EC and PSC after PCA result mainly in thickening of the sinusoidal barrier. This increase may impair exchanges between the sinusoidal lumen and Disse space and contribute to functional abnormalities.

Animals↗