To evaluate the effects of oxygen toxicity in the pregnant rat at high and low concentrations of oxygen, an oxygen-consumption apparatus was devised to measure the consumption of oxygen continuously over long periods. Oxygen consumption, partial oxygen pressure on the skin (tcPo2), and lipid peroxide levels in the serum were measured. There was a close correlation between oxygen consumption and body weight of rats that weighed between 150 g and 450 g. Oxygen consumption during the later stages of pregnacy increased by 1.8 ml/day, an increase of 8%. Oxygen consumption by rats during parturition increased markedly for up to 1 h and then reached and remained at a plateau value until the end of delivery. Exposure of pregnant rats to low concentrations of oxygen resulted in a marked depression in oxygen consumption and tcPo2 during the exposure time. A significant increase in the lipid peroxide level in serum was observed in the mother rat after birth and in the newborn offspring of pregnant rats exposed to 16% oxygen for 3 h.3h.Correspondence : Dr. Yoshihiro YOSHIMURA at the above address.
Organ distribution pattern, and blood clearance were examined by giving <99m>Tc-phytate (<99m>Tc-P) to the normal dogs. At the same time, the relation between the severity of hepatic function and blood clearance of <99m>Tc-P was studied by using the dogs with acute hepatic dysfunction experimentally induced by carbon tetrachloride (CCl4) administration. Furthermore, a comparative discussion on blood clearance test of <99m>Tc-p was made with serum transaminase test. It appeared appropriate to administer <99m>Tc-P at the dose of 100 μg/kg in order to obtain an effective blood clearance curve. A major part of <<99m<Tc-p intravenously administered was taken up into the liver, while the remainder of small amount into the spleen, kidneys, lung, and so on. Little was recognized in the thyroid. The disappearance rate of <99m>Tc-P from blood decreased with the increase in dose of CCl4 and with the passage of time after the CCl4 administration. The blood clearance test of <99m>Tc-P in dogs showed a sensitive reaction for the acute hepatic dysfunction induced by CCl4 equally to the serum transaminase test.
Genotoxicity of fungal anthraquinones of islandicin, iridoskyrin and (-) rubroskyrin, and a colorant of insect origin, cochineal and its component, carminic acid, an anthraquinone, was examined in the hepatocyte primary culture/DNA repair test. The results were compared with that of versicolorin A, an anthraquinone with bisfuran ring, which had been proved to be genotoxic on this assay. All of these anthraquinones, differently from versicolorin A did not show clear response of DNA repair. The results suggest that these agents are not genotoxic carcinogens.
In order to investigate interrelations of plasma levels of potassium with those of the other electrolytes in case of intraperitoneal administration of hypertonic solution consisting of low potent substance, each of the three hypertonic solutions (2, 800 mOsm/L), i.e., 50% glucose, 8.12% sodium chloride, and 13.16% sodium sulphate, was intraperitoneally injected to rats in a dose of 3.5 ml/kg body weight. Blood was sampled from the femoral artery at 0, 5, 10, 20, 30 and 45 min after the administration and at the time-point of death. In all cases of the three administered groups, the plasma levels of magnesium was observed to start increasing from 5 min, and, then, the potassium levels from 10 min. The phosphorus levels did not show a significant increase unti1 20 min, showing later an abrupt increase until the death. Calcium, on the other hand, did not show any significant change in the plasma level until the death. These findings denote that a high osmotic pressure moves first intracellular water and magnesium ion to the outside of the cell, and, with a time delay, intracellular potassium ion is forced to move slowly to the outside. Finally, intracellular phosphorus seems to be released into the extracellular space as a result of damages by suppression of mitochondrial oxidative phosphorylation and by activtion of phospholipase both of which were caused directly or indirectly by a critical osmotic force.