Fibrin clots exposed to mixtures of plasmin with appropriate levels of ϵ-amino-n-caproic acid, lima beam trypsin inhibitor, or soybean trypsin inhibitor underwent greater lysis, after washing and further incubation with buffer only, than did clots exposed to plasmin alone. The destruction of plasmin by antiplasmin was antagonized by the bean inhibitors, but was potentiated by ϵ-amino-n-caproic acid.
Isolated guinea pig atria perfused with epinephrine were found to bind this amine even after repeated washings. Catecholamine analyses indicated a concurrent depletion of tissue norepinephrine which appeared to be replaced with epinephrine. Histochemical observations showed that the binding of epinephrine was within the sympathetic nerve fiber plexus.
Normal hematological values for mongrel, male guinea pigs are given. A comparison with values found in the literature showed slightly higher erythrocyte and lower leukocyte levels, higher proportion of lymphocytes, and lower proportions of other cells in the differential count.
The plasma electrolyte responses of the mammal and reptile on exposure to environmental temperatures from 0° to 37° were different. At high temperature (37°C) the activity of the mammal decreased, and plasma electrolyte levels rose in the first 12 hours but returned to normal by 1 week, despite a sustained increase in both haematocrit and plasma protein. At low temperatures (0°C) there was evidence of a falling urinary Na/K ratio, but little change in plasma electrolytes.
1. Ammocoetes of Lampetra planeri were treated with solutions of testosterone propionate or oestradiol benzoate.
The sugar consumption of the same cell population was examined before and after infection with virulent or attenuated Type I Poliovirus, Mahoney and LSc strains or Echo 6 virus. The energy requirements of virus production, as derived from glucose are not different from that necessary for normal cell life, under the experimental conditions. There is no difference in this respect, if the infection starts with intact virus, or with viral RNA. Mahoney, LSc, Echo 6 viruses behaved alike. The titration of intracellular virus revealed the usual sequence of virus synthesis and definite intracellular virus titers at the end of 6 hours experimental period. Thus, the virus infection, adsorption, penetration, eclipse and re-synthesis of virus did not cause measurable quantitative difference from normal, regarding the glucose utilization, when the same cell population was assayed before and after inoculation with virus or viral nucleic acid.
The digitalis-like action of 5 substances, naturally occuring or partially synthetized from the aglycones of Adonis vernalis L. has been verified. Their activity as measured by LD in etherized cats has been determined.
1-Methylimidazole-4-acetic acid (MeImAA) constitutes a major component of histamine metabolites in human urine. This has been shown by isotope-dilution technique upon injection of 14C-labelled histamine1–3. In man about 45% of injected radioactive histamine is excreted as MeImAA. Very likely the estimation of this compound in urine may throw light on histamine metabolism under normal and pathological conditions.
The importance of iron in biological systems has been well established. Much of the interpretation of iron in tissues has rested upon total iron analysis of the tissue without consideration to the distribution and form of iron within the cells.
The administration of morphine to rats produces a significant decrease in the amount of CO-binding pigment, paralleling the decrease in the drug metabolizing enzyme activities, in the liver microsomal fraction. However, when the liver microsomal-supernatant fraction was divided by ammonium sulfate fractional precipitations, the microsomal cytochromes and the narcotic drug demethylases were precipitated in the same subfractions, but not in the same relative proportions.
Estimation of the daily thyroxine I131 disappearance rate in cattle following sudden exposures to heat (38°C) and cold (1°C) conditions demonstrated that (a) the time required for thyroid function to decrease from normal values under heat stress was at least 60 hours, (b) the time for increased thyroid activity under cold required about 36 hours, and (c) the readjustment of the thyroid gland from hot and cold to the thermoneutral zone (18°C) required at least 108 hours. These findings indicated that the adjustment of cattle to a stress condition by alteration of thyroid activity is a relatively slow process. This provides the evidence that thyroid function is not involved in the early stages of acclimation, but it has a major role in the compensation stage of acclimation to the new environment.
Stressed rats exhibit significantly decreased blood levels of hexobarbital, pentobarbital and meprobamate, but not phenobarbital, after administration of these drugs. The ability of stress to alter drug blood levels is absent in hypophysectomized and adrenalectomized animals and can be blocked by pretreatment of rats with morphine prior to stress. Pentobarbital blood levels can be lowered in adrenalectomized rats by corticosterone but not ACTH and by both corticosterone and ACTH in hypophysectomized animals. Treatment of rats with the protein synthesis inhibitor, Actinomycin D, blocks the ability of stress to lower pentobarbital blood levels. Liver perfusion experiments show that the metabolism of pentobarbital is stimulated in stressed rats and that this stimulation can likewise be prevented by Actinomycin D. The ability of stress situations to stimulate drug metabolism and its dependence upon an intact pituitary-adrenal axis is suggestive of a regulatory function of the endocrine system in mediating a rapid induction of liver microsomal enzymes responsible for drug metabolism.
The metabolism of serotonin-C14 in rat liver homogenate was shown to produce 5-hydroxyindoleacetaldehyde, 5-hydroxytryptophol, and 5-HIAA. The addition of nicotinamide and NAD, coenzyme of aldehyde dehydrogenase, to the incubation mixture increased the rate of formation of 5-HIAA with a concomitant decrease in the remaining 5-hydroxyindoleacetaldehyde. The addition of NADH, coenzyme for alcohol dehydrogenase, increased the rate of formation of 5-hydroxytryptophol with a concomitant decrease in the remaining 5-hydroxyindoleacetaldehyde and 5-HIAA.
