In vivo inhibition of citrate cleavage enzyme by polychlorinated biphenyls

Summary Polychlorinated biphenyls (Aroclor 1254, PCB) administered in the diet (0.01%, w/v) to rats inhibited citrate cleavage enzyme. The results suggest that the decreased activity might in part account for decreased fatty acid synthesis in the livers of PCB-treated rats.This research was supported by a grant from the National Institutes of Health (ES-00040). Aroclor 1254 was a gift of Monsanto Company, St. Louis, Missouri, USA.     

Enhanced inhibition of RNA synthesis by amanitins in in vitro cultured cells

Summary The inhibition of RNA synthesis by -amanitin on vitro cultured cells is very slow. The action of various analogues of the toxin was tested and some of them proved more effective. Moreover pretreatment of cell cultures with DEAE-dextran greatly enhanced the effect of -amanitin.Acknowledgments. We thank ProfessorTh. Wieland and Dr.H. Faulstich (Max-Planck-Institut, Heidelberg) for the generous gift of amanitins. This investigation was supported by grant No. 74.00637.65 from C.N.R. (Roma).     

Enhanced inhibition of RNA synthesis by amanitins in in vitro cultured cells.

The inhibition of RNA synthesis by alpha-amanitin on in vitro cultured cells is very slow. The action of various analogueoreover pretreatment of cell cultures with DEAE-dextran greatly enhanced the effect of beta-amanitin.     

A method for revealing inhibition of virus-induced synthesis of RNA

Zusammenfassung In mit Actinomycin D behandelten und mit dem Pseudogeflügelpest-Virus (NDV) infizierten Zellen gelingt der Nachweis einer ausgesprochenen Phase der Virus-RNS-Synthese. Mit dieser Methode lässt sich ebenfalls die Wirkung verschiedener Präparate auf die Virusnukleinsäuresynthese erfassen.     

In vivo inhibition of the tyrosinase of hamster melanoma with sodium diethyldithiocarbamate

Summary In vivo inhibition of the DOPA-oxydase activity of the soluble tyrosinase fraction of melanotic hamster melanoma is found after i.p. administration of diethyldithiocarbamate, with considerable increase in the content of SH-groups which probably play the role of free radical scavengers.     

In vitro inhibition of catalase by ovomucoid

Riassunto L'ovomucoide acquista spiccata attività anticatalasica dopo ebollizione. L'ovomucoide attivo dopo liofilizzazione o precipitazione alcoolica diviene inattivo; l'attività viene ripristinata con nuova ebollizione. L'ovomucoide attivo anche dopo dialisi perde l'attività che viene riacquistata con l'aggiunta di sali e successiva ebollizione. L'attività anticatalasica è dovuta ad una nuova configurazione instabile dell'ovomucoide.     

In vivo inhibition of the tyrosinase of hamster melanoma with sodium diethyldithiocarbamate.

In vivo inhibition of the DOPA-oxydase activity of the soluble tyrosinase fraction of melanotic hamster melanoma is found after i.p. administration of diethyldithiocarbamate, with considerable increase in the content of SH-groups which probably play the role of free radical scavengers.     

In vivo inhibition by dopamine of 5-hydroxytryptamine-stimulated ovarian maturation in the red swamp crayfish,Procambarus clarkii

In vivo dopamine antagonizes the ovary-stimulating action of 5-hydroxytryptamine in the red swamp crayfish,Procambarus clarkii.     

In vitro Polio virus inhibition by two guanidino-pyrimidines

Riassunto La 2-guanidino-pirimidina solfato e la 4-guanidino-2,6-dimetilpirimidina solfato inibisconoin vitro la moltiplicazione del poliovirus e del Coxsackie B₃ ma non quella del virus vaccinico e dell'adenovirus 5. L'analogia di comportamento con la guanidina è documentata oltre che da ciò, dalla esistenza di una resistenza e di una dipendenza crociata. Si dimostra cioè che non tutte le sostituzioni nella molecola della guanidina comportano una perdita dell'attività antivirale, come ritenuto in precedenza.     

In vitro inhibition of anaerobic glycolysis by phenothiazine ataractic drugs

Zusammenfassung Im Gegensatz zu Feststellungen anderer Forscher hemmten Chlorpromazin und zwei strukturell verwandte ataraktisch wirkende Phenothiazinderivate die anaerobe Glykolyse von homogenisiertem Rattenhirn. Der Nachweis dieser Hemmung bedarf einer längeren Inkubation, was auf die Mitwirkung eines zeitbedingten Vorgangs, wie metabolische Umwandlung der Phenothiazine in Hemmstoffe, deutet.     

Murine primitive neuroectodermal tumor: nucleolar isolation and RNA polymerase inhibition

Summary A nucleolar isolation procedure was developed for the murine primitive neuroectodermal tumor originally induced with methylcholanthrene. This procedure utilizes sonication for breakage of the nuclei at a magnesium concentration which disperses the extranucleolar chromatin. The nucleoli retain RNA synthetic activity which is inhibited to about 90% by actinomycin D and the chemotherapeutic drug adriamycin.Acknowledgments. This work was supported in part by USPHS Grant CM-67058. We wish to thank Dr William Brooks for his generous support of this project.     

In vivo effect of inhibin on FSH uptake by rat testis

Summary Simultaneous administration of inhibin and¹²⁵I-hFSH significantly decreased the uptake of¹²⁵I-hFSH by the immature rat testis. The data suggest that inhibin may modulate FSH action at the gonadal level.