The effect of various diuretic agents on renal electrolyte and urea concentration gradients in rats

Zusammenfassung Die Konzentrationsgradienten von Na+und Harnstoff im Rattennierengewebe werden durch intravenöse Applikation von Merallurid, Salyrgan und Hydrochlorothiazid nicht beeinflusst. Die Änderung des Na-Gradienten nach Aminophyllin hängt von der Injektionszeit ab. Acetazolamid-, Chlorothiazid- und Furosemid-Injektion führt jedoch zur Senkung oder zum Verschwinden eines Na-Gradienten. Die Kaliumkonzentration in der Rinde und Papilla wird durch Hg- und Sulfonamid-Diuretica erniedrigt.     

Elevated UV-B radiation reduces genome stability in plants

Long-term depletion of the stratospheric ozone layer contributes to an increase in terrestrial solar ultraviolet-B radiation. This has deleterious effects on living organisms, such as DNA damage. When exposed to elevated ultraviolet-B radiation (UV-B; 280-315 nm), plants display a wide variety of physiological and morphological responses characterized as acclimation and adaptation. Here we show, using special sun simulators, that elevated solar UV-B doses increase the frequency of somatic homologous DNA rearrangements in Arabidopsis and tobacco plants. Increases in recombination are accompanied by a strong induction of photolyase and Rad51 gene expression. These genes are putatively involved in major DNA repair pathways, photoreactivation and recombination repair. In mutant Arabidopsis plants that are deficient in photoreactivating ultraviolet-induced cyclobutane pyrimidine dimers, recombination under elevated UV-B regimes greatly exceeds wild-type levels. Our results show that homologous recombination repair pathways might be involved in eliminating UV-B-induced DNA lesions in plants. Thus, increases in terrestrial solar UV-B radiation as forecasted for the early 21st century may affect genome stability in plants.     

Cholesterol content and cholesterol esterifying activity of various organs in guinea pigs

In various organs of the guinea pig, the total cholesterol content of an organ was significantly correlated with the percentage of esterified cholesterol present in this organ. Cholesterol esterifying capacity was shown in most organs, with highest activities in the adrenals, the spleen and the liver. The significant correlation found between the cholesteryl ester content of an organ and its acyl cholesterol acyltransferase activity suggests a possible role of this enzyme in determining the level of the total and esterified cholesterol in a tissue.     

Red blood cell glutathione peroxidase in simple trisomy 21 and translocation 21/22

Summary Red blood cell glutathione peroxidase activity was increased by bbout 50% in all Down's syndrome patients studied. It was slightly lower in translocation as compared with simple trisomy 21 but much higher with respect to controls. We are indebted to Prof. M. Ferguson-Smith from the Department of Medical Genetics, Royal Hospital for Sick Children, Glasgow, Scotland, for helpful discussions regarding our results.     

The effect of noradrenaline on heat production in the new-born pig

Résumé La production de chaleur, la température du corps et du QR de 6 porcelets âgés de 4 à 13 jours, avant et après l'injection s.c. de noradrénaline (200 g/kg) ont été déterminées. On n'a pas constaté l'effet de l'injection de noradrénaline sur les animaux de 4–6 jours, pendant que le métabolisme et la température du rectum des porcelets âgés de 11–13 jours augmentaient distinctement, et que la valeur du QR a baissait significativement.

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The authors are indepted to Dr.Maria Kotarbiska-Urbaniec for the provision of experimental animals.     

The composition of the renal medulla during natriuresis accompanying saline loading in the rat

Zusammenfassung In 38 Ratten wurde die Na- und Harnstoff-Konzentration im Gewebewasser der Nierenrinde, des Nierenmarks und der Papillenspitze nach einer Infusion von isotoner Kochsalzlösung festgestellt. Die Konzentration beider Stoffe war in der Papillenspitze und in dem Nierenmark bedeutend niedriger als bei den Kontrollratten.     

Morphological basis of follicle cells - oocyte interaction in normal pupae and isolated pupal abdomina ofGalleria mellonella L.

Résumé Le plasmalemme des oocytes se caractérise par une grande activité pinocytosique au cours de la vitellogenèse. Celle-ci semble être contrôlée par des facteurs hormonaux, car l'ablation des glandes endocrines bloque complètement cette activité.

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This work was supported in part by Grant No. FG-Po-221 from the U.S. Agricultural Department.