Biomedical subjects
Publications and source records attributed to B Paletta.
A computer-aided arrangement is described which allows kinetic and regulative studies with enzymes, organelles and cells in an open system. This is demonstrated with some simple examples.
The time function of cortocosteroid level in plasma of rats under two different 222Rn concentrations was investigated. Both curves show a maximum after 8h. Whereas the higher activity of 222Rn produces a second maximum after 5 days, the lower activity reaches its second maximum not before 9 days. From both time functions, a two-step mechanism in the intracellular control can be concluded.
3 groups, each consisting of 5 subjects in the following age ranges (A 4 to 6 years, B 25 to 45 years, C 60 to 70 years) were given fluoride in the form of a single dose of 6 mg. Fluoride excretion in the urine was subsequently investigated over a period of 24 hours. In a second experiment a daily dose of 6 mg of F- was given to the 3 groups over a period of 10 days. The urinary excretion was determined in 24-hour urine samples. The results are presented in two figures. 1. A time drift in urinary fluoride excretion in the direction of delayed fluoride metabolism was seen in group C subjects. 2. A periodic increase in the urinary fluoride values was also seen in these elderly subjects, indicative of an altered regulatory mechanism.
The time function of free fatty acids and of corticosterone in plasma in fed and fasted rats was investigated. Also a study of the influence of hypoxia on the concentration of plasma free fatty acids was carried out. Whereas fasting does not seem to stimulate lipolysis markedly before 12 h, 2 h of hypoxia elevate the free fatty acid level to its maximum. In the fasted condition, all values are significantly higher than corticosterone in the fed animal.