Zum Proliferations-Stoffwechsel der Rattenleber nach Teilhepatektomie. Autoradiographische Untersuchungen mit3H-Cytidin,-Phenylalanin und -Thymidin

Summary During the first wave of parenchymal liver regeneration in adult rats after partial hepatectomy, the cellular synthesis and migration of RNA and the metabolism of protein were studied by autoradiography following an injection of³H-cytidine or³H-l-phenylalanine and double injections of 1 of these precursors +³H-thymidine. The following results were obtained: the synthesis and migration of RNA and the metabolism of protein are enhanced under these conditions of proliferation. In spite of this, the relation of metabolic activity in nucleolus, karyoplasm and cytoplasm remains constant. By double injection techniques it is proved that no differences exist in migration of RNA into the cytoplasm and cytoplasmic protein synthesis between cells with or without DNA synthesizing nuclei.

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Mit Unterstützung der Deutschen Forschungsgemeinschaft.     

7α-hydroxylation of dehydroepiandrosterone in human testis and epididymis in vitro

Zusammenfassung Zerhackte menschliche Hoden und Epididymis wurden mit Dehydroepiandrosteron ohne Kofaktoren bebrütet und es wurden unter anderem 7-und 7-Hydroxydehydroepiandrosteron und 5-Androsten-3, 7, 17-triol charakterisiert. Die Ausbeute an 7-hydroxylierten Metaboliten war fast gleich in Hoden und Epididymis.

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The authors wish to thank Mr.J. Novák for his excellent technical assistance. We are indebted to Dr.J. E. Jirásek for generous performance of histological control of tissue and to Dr.S. Röhling for his kind pernission of radioactivity measurements.     

Destruction of the platelet aggregating activity of ristocetin A

Summary Hydrolysis of ristocetin A in 0.1 N HCl at 37°C for 2 h resulted in the loss of its ability to induce platelet aggregation in platelet-rich plasma derived from guinea-pigs and humans. However its antibiotic activity againstStaph. aureus was not lost.This work was supported, in part, by a contract from the National Heart, Lung, and Blood Institute (USPHS).     

Fibrinolytic proteases in snake venoms

Zusammenfassung Fibrinolysine zweier Schlangengifte haben — im Gegensatz zu Plasmin und Trypsin — keinen Plasminogen-aktivierenden Effekt, noch sind sie durch Proteasen-Inhibitoren gehemmt. Sowohl in vivo wie auch in vitro sind sie durch Plasmaproteine inaktiviert, was jedoch nicht auf ₁ und ₂-Antiplasmine zurückzuführen ist. Die Spaltprodukte der Toxin-Fibrinogenolyse besitzen einen hohen Gehalt an Antithrombin VI.