Biomedical subjects

S Tazuma

Publications and source records attributed to S Tazuma.

75 records · Page 5Linked to original sources

PubMedDate not supplied

Reversibility of organic anion-induced cholestasis: association with compensatory hypersecretion of biliary phospholipid and protein in the dog.

The effect of a concomitant infusion of organic anions, structurally related phthaleins, on bile flow was studied in anaesthetized dogs. A combination of rose bengal and sulfobromophthalein was found to uniquely and synergistically produce an acute, reversible form of intrahepatic cholestasis (< 10% of control level). This phenomenon was not observed with the administration of those individual organic anions at concentrations previously associated with the induction of intrahepatic cholestasis. The infusion of either a micelle forming bile salt, sodium taurocholate, or a non-micelle forming bile salt, sodium dehydrocholate, rapidly reversed the intrahepatic cholestasis (within 20 min after bile salt infusion). During the choleretic phase immediately following the bile salt infusion, a transient but marked hypersecretion, a disproportionately increased output in relation to that of bile acids, of biliary phospholipid (176% of control level by taurocholate and 138% of control level by dehydrocholate), and an even more striking amount of biliary protein hypersecretion were observed (392% of control level by taurocholate and 357% of control level by dehydrocholate). Although the significance of these new post-cholestatic observations requires clarification, it is suggested that the intrahepatic cholestasis induced by organic anions reflects a reversible defect in the mechanism(s) involved in transcellular transport.

Animals↗

PubMedDate not supplied

An estimation of human bile metastability: clinical application of a sensitive cholesterol crystal growth assay.

The formation of cholesterol monohydrate crystal initiates cholesterol gallstone formation. The nucleation time (NT), a light microscopy method, is used currently to estimate human bile metastability. Recently, a cholesterol crystal growth (CCG) assay utilizing photometric turbidity to quantitate cholesterol crystallization was developed using model bile systems. The object of this study was to determine whether this novel CCG assay was applicable to the quantitative assessment of native human bile metastability. Human gall-bladder bile samples were collected from patients undergoing cholecystectomy. There were five patients with cholesterol gallstone and five stone-free patients. A significant correlation between the onset time measured by the CCG assay and the NT observed by light microscopy was found in our modified assay condition where interference by bilirubin was negligible (P < 0.01). Also, the growth rate measured by the CCG assay significantly correlated with the NT (P < 0.05). These results indicate that the CCG assay is applicable to quantitative assessment of human bile metastability reflected by cholesterol crystal nucleation and that the cholesterol crystal growth is also conveniently estimated by this method.

Bile↗

PubMedDate not supplied

Hydrophilic bile salts and liposomes inhibit hydrophobic bile salt-induced release of glycoprotein by guinea-pig gall-bladder.

Bile salts can be cytotoxic to mucosal surfaces, because of their detergent properties. This is not normally seen under physiological circumstances in the gall-bladder. To further study normal mucosal defence mechanisms, the present study was performed to examine the effects of liposomes and hydrophilic bile salts on hydrophobic bile salt-induced release of radiolabelled glycoproteins from explants of guinea-pig gall-bladder. Glycoprotein release was correlated with the degree of hydrophobicity of bile salts, as determined by the retention factor in reversed-phase high-performance liquid chromatography. Hydrophobic bile salt-induced release of glycoproteins was reduced by liposomes and hydrophilic bile salts. The inhibitory effect of liposomes was directly related to the degree of saturation of their fatty acyl chains, and that of hydrophilic bile salts was related to the degree of hydrophilicity. These findings suggest that vesicles and hydrophilic bile salts may play a cytoprotective role against membrane damage passively caused by hydrophobic bile salts in the biliary system, and that such damage may occur according to the quantitative and qualitative imbalance among these factors.

Animals↗