Influence of a low-selenium diet on erythrocyte glutathione peroxidase and alkane production in exhaled air of rats as a measure of lipid peroxidation in vivo during growth

Erythrocyte glutathione peroxidase activity and alkane production in exhaled air of growing rats were studied as a measure of lipid peroxidation in vivo. When 4-weeks-old, rats were fed a low-selenium (0.05 mg/kg) refined soy concentrate-based diet but adequate in vitamin E and other nutrients. Rats of control groups were fed the same diet supplemented with varying amounts of selenium as sodium selenite. After 10 weeks, erythrocyte glutathione peroxidase activity in the group fed the low selenium diet had decreased to about 40% of the original level. Feeding this diet for a longer period resulted in a slow increase of the glutathione peroxidase level. After about 37 weeks, this level was equal to the initial level. During the same period of rapid growth, ethane and pentane production in the exhaled air of a group of similar animals on the diet containing 0.05 mg Se per kg was slightly although significantly higher compared with the levels of animals on a supplemented (0.4 mg Se per kg) diet. Differences were highest when glutathione peroxidase activity levels in the erythrocytes were lowest and negligible at the start of the experiment and after the period of rapid growth. These results support the view that the seleno-enzyme glutathione peroxidase is active in the defense mechanism of the cell against lipid proxidation.     

Effects of confinement (110 and 240 days) on neuroendocrine stress response and changes of immune cells in men.

The aim of the study was to evaluate the effects of long-term confinement on stress-permissive neuroendocrine and immune responses in humans. Two groups of four male subjects were confined 240 days (group 240) or 110 days (group 110) in two space modules of 100 or 200 m3, respectively. During confinement, none of the volunteers developed psychic stress as could be examined and verified by a current stress test. However, in group 240 but not in group 110, the diurnal rhythm of cortisol secretion was slightly depressed and the urine excretion of norepinephrine significantly increased. The innate part of the immune system became activated as seen by a rise in the number of circulating granulocytes and the enhanced expression of beta2-integrins. In contrast, the ratio of T-helper to T-suppressor cells decreased. All these effects, observed during confinement, were even more pronounced in both groups when values of endocrinological and immunological parameters were compared between before and 1 wk after the end of the confinement period. Hence, return to normal life exerts pronounced effects to a much higher degree, irrespective of how long or under which conditions individuals were confined. Because the delayed-type hypersensitivity skin reaction against recall antigens remained unaffected, it is to be presumed that confinement appears to induce distinct sympathoadrenergic activation and immunological changes but no clinically relevant immunosuppression.     

Detection and characterization of a selective endopeptidase from Plasmodium berghei by using fluorogenic peptidyl substrates

By using fluorogenic peptidyl-3-amino-9-ethyl-carbazole a highly selective endopeptidase for the Val-Leu-Gly-Arg sequence was demonstrated in endoerythrocytic stages of $\text{Plasmodium berghei}$. Val-Leu-Gly-Arg-endopeptidase showed a maximum activity in pH range 7.0–8.0; it was completely inhibited by 1 mM leupeptin and 1 mM antipain. A complete inhibition was also obtained by 15 mM chloroquine. This trypsin-like activity was negligible in uninfected red blood cells. The high sensitive fluorogenic procedure could be performed on cell fractions, cell lysates as well as supernatants.     

Chick and quail specific pattern of endplates and fibre-types in the plantaris muscle

Species-specific endplate distribution and fibre-type pattern were found in the plantaris muscle (PL) of the chick and quail. The PL is proposed as a model for studies of nerve-muscle interactions in chimeras.