Failure of actinomycin D to inhibit appearance of clotting activity by vitamin K in vitro

Zusammenfassung Lebergewebeschnitte mit Cumarin antikoagulentienvorbehandelter Ratten zeigen den Faktor VII im Medium nur beim Zusatz von Vitamin K. Die Vitamin-K-Wirkung wird bei gleichzeitigem Zusatz von Aktinomycin D nicht beeinflusst. Diese Beobachtung stimmt nicht überein mit der Hypothese, dass Vitamin K durch Beförderung der Auslösung der für die Synthese des Faktors VII spezifischen t-RNA eine Wirkung ausübt.     

Prompt effect of insulin in vitro on the esterolytic activity of tissue homogenates not modified by actinomycin D

Zusammenfassung Die in vitro-Wirkung des Insulins (Konzentrationsbereich von 50–100 000µU/ml des Inkubationsmediums) auf die esterolytische Aktivität der Fettgewebe, Homogenate von Myokard, Lunge und Muskel wurde bei Ratten beschrieben. Es ergibt sich eine von der Enzym-Synthese unabhängige schnelle Insulinwirkung.     

Failure of coffee to inhibit the pharmacodynamic activity of morphine in vivo

Summary High doses of caffeine-containing as well as decaffeinated instant coffee neither inhibited morphine-induced analgesia in mice nor the morphine-induced fall of blood pressure, heart rate and respiratory rate in rats. On the contrary, caffeine-containing coffee even enhanced the analgesic effects of morphine in mice. Coffee thus does not exhibit opiate-antagonizing activity in the whole organism in vivo. The very weak morphine-antagonistic efficacy of coffee powder in the myenteric plexus-longitudinal muscle preparation from the guinea pig ileum is of no practical importance.     

Failure of coffee to inhibit the pharmacodynamic activity of morphine in vivo

High doses of caffeine-containing as well as decaffeinated instant coffee neither inhibited morphine-induced analgesia in mice nor the morphine-induced fall of blood pressure, heart rate and respiratory rate in rats. On the contrary, caffeine-containing coffee even enhanced the analgesic effects of morphine in mice. Coffee thus does not exhibit opiate-antagonizing activity in the whole organism in vivo. The very weak morphine-antagonistic efficacy of coffee powder in the myenteric plexus-longitudinal muscle preparation from the guinea pig ileum is of no practical importance.     

Reversible depression of spontaneous brain electrical activity induced by actinomycin D and 7-aminoactinomycin D in rats

Summary Various types of actinomycin (C, D, S₂, I and V) and 7-amino-analogue of actinomycin D were injected into the right lateral ventricle of the brain through a chronically implanted cannula. In rats but not in mice actinomycin D, actinomycin S₂ and 7-aminoactinomycin D caused depression of EEG, while cardiac and respiratory activity were maintained. This effect of the EEG was reversible and a normal EEG pattern reappeared at least 3 h after administration.     

Effect of actinomycin D or puromycin on microsomal testosterone hydroxylase activity enhanced by testosterone in female rat liver

Summary The injection of testosterone propionate for 4 successive days into female rats resulted in an increase of the in vitro conversion of the hydroxylated testosterones from testosterone by the hepatic microsomal, fraction, but no change in the content of microsomal cytochrome P-450 occurred. Actinomycin D or puromycin, which was administered for 4 days with injections of testosterone propionate, prevented the enzyme induction.     

Dissociation of separate mechanisms of estrogen action by actinomycin D

Summary Pretreatment with actinomycin D 1 h before estrogen administration completely blocks estrogen-induced increases in uterine RNA and protein content, but does not counteract estrogen-induced uterine eosinophilia, edema and increase in glycogen content.Acknowledgments. This work was supported by the Belgian Ministry of Scientific Policy (Concerted Actions of Research) and by the Servicio de Desarrollo Cientifico, Artistico y de Cooperacion Internacional from the University of Chile.     

Alleviation of the toxicity of actinomycin D by uridine and thymidine on the morphogenesis of chick embryos cultivated in vitro

Zusammenfassung Untersuchung über die Wirkung von Actinomycin D auf Primitivstreifen- und Entwicklungsstadien der Kopfregion bei Hühnerembryonen in vitro: Anormale Entwicklung des Zentralnervensystems, der Somiten und des Herzens; diese Effekter konnten durch Thymidin oder Uridin zum Teil aufgehoben werden.

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One of us (S.M.K.) wishes to thank the UGC for financial assistance

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We thank Dr.P. N. Joshi of biochemistry and Mr.S. Biswas of statistics for their valuable help in the discussion.     

Inhibition of DNA synthesis and cell division by actinomycin D

Zusammenfassung Nach in-vitro-Kultur oder Verwundung in vivo der Froschlinsen wird zuerst meistens, im Epithel, eine intensive DNS-Synthese gefunden auf die später zahlreiche Kernteilungsfiguren folgen. Nach Behandlung mit Actinomycin D werden diese Reaktionen stark gehemmt. Autoradiographische Untersuchungen mit dem DNS-Vorläufer H-3-Thymidin und dem RNS-Vorläufer H-3 Uridin erlauben den Schluss, dass die DNS-Synthese (und damit Zellteilung) von einer früheren RNS-Synthese abhängt.

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This work was supported in part by Public Health Service Grant No. NB-05425-01 and also by institutional grant 71D from the American Cancer Society.

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Supported by U.S. National Science Foundation grant No. GE-6534 5/410-0056.