Calcium dependence of bleb formation and cell death in hepatocytes.

Calcium dependence of bleb formation and cell death was evaluated in rat hepatocytes following ATP depletion by metabolic inhibition with KCN and iodoacetate ('chemical hypoxia'). Cytosolic free Ca2+ was measured in single cells by ratio imaging of Fura-2 fluorescence using multiparameter digitized video microscopy. Cells formed surface blebs within 10 to 20 minutes after chemical hypoxia and most cells lost viability within an hour.

Extracellular acidosis delays onset of cell death in ATP-depleted hepatocytes.

A fluorometric assay using propidium iodide total fluorescence was utilized to quantitate cell viability in hepatocyte suspensions continuously. For viable hepatocytes exposed to KCN, fluorescence was linearly proportional to lactate dehydrogenase release and to nuclear labeling by propidium iodide. In KCN-treated hepatocytes, iodoacetate eliminated the protective effect of the fed state and fructose against the onset of cell death.

Irreversible injury in anoxic hepatocytes precipitated by an abrupt increase in plasma membrane permeability.

Using low-light digitized video microscopy, the onset, progression, and reversibility of anoxic injury were assessed in single hepatocytes isolated from fasted rats. Cell-surface bleb formation occurred in three stages over 1-3 h after anoxia. Stage I was characterized by formation of numerous small blebs.

Primary biliary cirrhosis: associations with class II major histocompatibility complex antigens.

Tissue injury in primary biliary cirrhosis is thought to be mediated by immune mechanisms. Various Class II antigens of the major histocompatibility complex are associated with autoimmune diseases and their differing clinical manifestations. Thus, the aim of this study was to examine the relationship between primary biliary cirrhosis, its clinical manifestations and serologically defined Class II antigens (HLA-DR and HLA-DQ).

Hepatic processing of cholecystokinin peptides. II. Cellular metabolism, transport, and biliary excretion.

We have shown that radiolabeled cholecystokinin octapeptide (CCK-8), CCK-8-desulfate, and CCK-4 are extracted by the liver in a structurally specific manner. Thus, we studied the fate of the extracted radiolabeled peptides by quantitating biliary excretion and determining the nature of the metabolites in bile. There was rapid biliary excretion of labeled CCK-8, CCK-8-desulfate, and CCK-4 by the isolated, perfused rat liver; greater than 75% of the extracted dose and greater than 20% of the injected dose appeared in bile within 20 min after a single pass across the liver.

Hepatic processing of cholecystokinin peptides. I. Structural specificity and mechanism of hepatic extraction.

Since the liver is a target tissue of many biologically important molecules, we have studied the hepatic uptake of cholecystokinin (CCK) with the isolated, perfused rat liver and a series of radioiodinated and unlabeled CCK peptides. Of the naturally occurring forms of CCK, cholecystokinin octapeptide (CCK-8) was extensively extracted (26 +/- 0.7% of Bolton-Hunter-labeled CCK-8, 59% of unlabeled CCK-8) in a single pass through the liver, while CCK-33 was minimally extracted (3.