Hypoxia tolerance of coronary endothelial cells.
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Adenine Nucleotides↗
Biomedical subjects
P Wissemann
Publications and source records attributed to P Wissemann.
Lipid peroxidation and cell viability in isolated hepatocytes in a redesigned oxystat system: evaluation of the hypothesis that lipid peroxidation, preferentially induced at low oxygen partial pressures, is decisive for CCl4 liver cell injury.
An oxystat system is described which is capable of maintaining steady-state oxygen partial pressures (PO2) at levels between 0.1 and 300 mm Hg for hours or even days in incubations of respiring cells. The system was used to study effects of the hepatotoxin carbon tetrachloride (CCl4) on lipid peroxidation and cell viability in isolated hepatocytes from phenobarbital-pretreated rats at various steady-state PO2. At PO2 below 35 mm Hg, with a maximum effect at 7 mm Hg, CCl4 induced an immediate lipid peroxidation, the rate of which slowed down during further incubation. AT PO2 between 35 and 70 mm Hg, CCl4 initially induced only slight lipid peroxidation, while there was a significant increase in lipid peroxidation after approximately 30 min. At PO2 above 100 mm Hg, no lipid peroxidation was induced by CCl4. At PO2 of 70 mm Hg and below, with the maximum effect at 3 mm Hg, CCl4 also induced marked losses of cell viability. Under anaerobic conditions and at PO2 greater than 70 mm Hg, CCl4 was without effect on the viability of the liver cells. Cells isolated from the pericentral area of the liver lobule showed more lipid peroxidation and loss of cell viability than cells from the periportal area of the lobule. These results provide further evidence for the decisive role of lipid peroxidation, preferentially induced at low PO2, in CCl4 liver injury.
Animals↗
A computer-supported oxystat system maintaining steady-state O2 partial pressures and simultaneously monitoring O2 uptake in biological systems.
A feedback-controlled oxystat system is described maintaining steady-state O2 partial pressures (pO2) between 0.01 mmHg (14 nM-O2) and 150 mmHg (210 microM-O2) and simultaneously monitoring O2 uptake at rates between 0.1 and 120 microM-O2 X min-1 in suspensions of cells, in subcellular fractions and in solutions of enzymes. At pO2 values between 0.2 and 150 mmHg (0.28 and 210 microM-O2) a polarographic O2 sensor was used, and below a pO2 of 0.2 mmHg (0.28 microM-O2) the O2-dependent luminescence of the photobacterium Vibrio fischeri was utilized to monitor the actual pO2. At a selected pO2, O2 supply is maintained by injecting appropriate amounts of O2-saturated aqueous medium into the reaction chamber by using a motor-driven burette. The oxystat system is under control of a computer that reads the O2 sensors, interacts with the motor-driven burette, calculates the O2 uptake from the amounts of O2-saturated medium added, collects data from further measuring devices and provides the documentation of the results during incubation.
Computers↗