Der Einfluss von Acetylcholin auf den Calciumumsatz ruhender und kontrahierender Vorhofmuskulaturin vitro

Summary Acetylcholine 5 × 10^–8 g/ml reduces the Ca⁴⁵ uptake of the beating left atria of guinea-pig; the tissue calcium is not altered. In resting atria, acetylcholine 5 × 10^–7 g/ml has no influence upon the calcium content and Ca⁴⁵ uptake. It is concluded that acetylcholine acts by shortening the action potential duration and thereby reduces the release of cellular calcium per excitation.

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Mit grosszügiger Unterstützung durch die Deutsche Forschungsgemeinschaft.     

Der Einfluss von Halothan und Chloroform auf die Feinstruktur und Proteinsynthese der Rattenleber

Summary Examinations by electron microscopic and autoradiographic techniques of whether chloroform and halothane alter protein synthesis in rat liver, demonstrate, that chloroform causes an early destruction of the granular endoplasmatic reticulum accompanied by a marked decrease of the protein synthesis in the centre of the acini. After anaesthesia with halothane, the granular endoplasmatic reticulum and the protein synthesis proved to remain unaffected.     

Der Einfluss von Calcium auf die Brenzcatechinaminfreisetzung

Summary (1) Experiments on isolated perfused suprarenals of cattle have shown that the acetylcholine-induced release of catechol amines, but not that of phenylethylamine, is dependent on calcium, since a perfusion with calcium-free Tyrode's solution abolishes the action of acetylcholine and not that of phenylethylamine. (2) Inincubation experiments with isolated chromaffin granules, calcium produces a dose-dependent, significant release of catechol amines even in physiological concentrations (2.5 mM). (3) Acetylcholine does not release catechol amines from isolated granules, either in the presence or in the absence of calcium.

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Forschungs-Stipendiat der A. von Humboldt-Stiftung.

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Ausgeführt mit Unterstützung der Deutschen Forschungsgemeinschaft.     

Der Einfluss von adrenergen Rezeptoren-Blockern auf die Wirksamkeit von Strahlenschutzsubstanzen

Summary The effect of -adrenergic receptor-inhibitors was examined in relation to the effectiveness of radioprotective agents. The results, when mice were irradiated, show that the receptor-inhibitors significantly reduced the effect of the applied protectors.     

Der Einfluss von Chlorpromazin auf die oxydative Phosphorylierung von Tumormitochondrien

Summary High concentrations of chlorpromazine cause a considerable decrease of the oxidative phosphorylation of tumor mitochondria and rat liver mitochondria. Regarding preliminary experimental and clinical investigations, we assume that malignant tumors can be sensitised to cytotoxic substances and ionising radiations impairing their energy metabolism by uncoupling the oxidative phosphorylation.     

Der Einfluss des Urin-pH auf die Aktivität von Urinenzymen

Summary The relationship between the pH of urine and the measured activity of ULDH, UAP and UAA was investigated in vivo and in vitro. The activity of ULDH and UAP is only half as much, or less, in acid urine (pH 4.8–5.1) as it is in alkaline urine (pH 7.0–8.1). The UAA activity, however, does not change in the pH range measured. The isoenzymes ULDH 2–4, present in alkaline urine of normal adults, does not appear in acid urine.     

Der Einfluss von 2-Deoxy-D-glucose auf die Substratoxydation in Ascites-Tumorzellen

Summary The effect of the glycolytic inhibitor 2-deoxy-D-glucose on the oxidation of¹⁴C-labelled substrates of the tricarboxylic acid cycle was investigated in ascites carcinoma cells of the mouse. In the presence of high concentrations of glucose, deoxyglucose stimulates the oxidation of pyruvate C-2 and C-3 to CO₂, but not the oxidation of succinate C-1,4 to CO₂. While deoxyglucose causes, in the absence of glucose, an inhibition of the oxidation of exogenous palmitate C-1 to CO₂, it causes, in the presence of glucose, a stimulation of the palmitate oxidation. There is a possible correlation between the effect of deoxyglucose on the intracellular ATP metabolism and the effect of deoxyglucose on the palmitate oxidation.     

Der Einfluss von 4-Benzylhydroxy-3,5-dijodbenzoesäure auf die oxydative Phosphorylierung von Leber- und Tumormitochondrien

Summary The effects of 4-benzylhydroxy-3,5-diiodobenzoic acid on isolated mitochondria ofWalker carcinosarcoma 256 and liver tissue of the same animals were compared. It was shown that, by the same concentrations of the uncoupling halo-phenol, the oxidative phosphorylation of tumor mitochondria was impaired in a higher degree than that of liver mitochondria.     

Einfluss von Streptomycin und von Tetracyclinen auf die Entwicklung keimender Samen

Summary Euler (1947) andM. L. Stein (1953) had observed that germinating seeds of barley, rye, wheat and other grasses are colourless when exposed to solutions containing more than 0.2% of streptomycin or dihydrostreptomycin. These plants are not inhibited in growth. The chlorophyll already formed is not destroyed by streptomycin.The present authors describe the bleaching effect on germinating seeds of chlortetracycline and tetracycline. These antibiotics inhibit or reduce the formation of chlorophyll in germinating seeds but the authors could not obtain this inhibition without toxic effects (reduced growth). Contrary to streptomycin, the tetracyclines are not able to precipitate nucleic acids and nucleoproteins.     

Der Einfluss von Tetracyclin auf die Vermehrung des Kartoffel-Blattrollvirus im VektorMyzus persicae

Summary Tetracycline hydrochloride treatment decreased the transmission rate of potato leafroll virus (PLRV) byMyzus persicae. It also prevented the PLRV-induced swellings of the A/F nuclei of the salivary gland. Apparently there is a connection between these two phenomena. The A/F cells may be a site of virus multiplication.     

Der Einfluss der Adenosintriphosphorsäure auf die Strahlenpneumonitis

Summary The administration of adenosintriphosphate in a dosage sufficient to decrease mortality to a significant degree does not decrease the incidence of radiation pneumonitis. Thus, the effect produced by ATP seems to depend on its action upon protein metabolism rather than on morphological cell structures.     

Der Einfluss der γ-Globuline auf die Viskosität

Summary Depending on concentration of fibrinogen, increasing concentrations of -globulines cause an exponential increase of viscosity, which is more pronounced, the higher the basic concentration of fibrinogenis. Fibrinogen that is dependent on -globulines and albumin, -globulines that is dependent on albumin, or albumin that is dependent on fibrinogen and -globulines do not show this behaviour.

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Für die zuverlässige Mitarbeit sei der biochem.-techn. Assistentin, Fräulein Ilse Stelter, gedankt.     

Der Einfluss sogenannter Ovulationshemmer auf die Esteraseaktivität des Endometriums

Summary Histochemical investigations were carried out in the endometrium of guinea-pigs after administration of Anovlar (4 mg ethinylnortestosterone-acetate and 0.05 mg ethynylestradiol). Histochemically a decrease of non-specific esterase activity was found in the endometrial as well as in the glandular epithelium after Anovlar treatment. The relationship of this enzyme to synthetic steroid hormones is briefly discussed.     

Der Einfluss verschiedener Psychopharmaka auf den Bluthistamingehalt von Ratten

Summary The concentration of histamine in plasma of rats is changed by injection of psychopharmacons as follows: decreased by narcotics (ether, chloroform) and phantastics (LSD, mescaline), increased by tranquilizers (reserpine, chlorpromazine) a hypnotic (numal) and psychotomimetics (iproniacide, amphetamine).     

Über den Einfluss von Natriumsulfit,Natriumtellurit und Natriumselenit auf die Retention von Zink,Kadmium und Quecksilber im Organismus

Summary The influence of sodium sulfite, sodium tellurite and sodium selenite on the retention of zinc, cadmium and mercury in mice was studied. The retention of mercury was increased by sodium selenite and by sodium tellurite. The retention of cadmium was increased only by sodium selenite. Sodium sulfite did not influence the retention of metals studied. The retention of zinc was not influenced by any compounds used.     

Der Einfluss von Barbituraten auf das ERG der isolierten Froschnetzhaut

Summary The influence of barbiturates on the electroretinogram was studied in the isolated perfused retina of the frog; a-, b-, and d-waves were altered differently. The effect (increase or decrease in amplitude) depended on the concentration as well as on the duration of application.     

Der Einfluss von Colchizin und Ethidium-Bromid auf den Gehalt radioaktiv markierter Uridin-Verbindungen in optischen Axonen von Teleosteern

Summary After application of colchicine to one eye, and subsequent injections of³H-histidine or³H-uridine into both eyes, a blockage of the transport in the optic system of teleosts could be demonstrated only for the fast protein-components. However, colchicine is able to depress the effectivity of ethidium-bromide, a blocker of mitochondrial RNA-synthesis. This finding is discussed in connection with the possibility that axonal mitochondria are associated with the neurotubules.

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Mit dankenswerter Unterstützung durch die Deutsche Forschungsgemeinschaft, die Herrn Prof. Dr.H. Rahmann (Münster) die Mittel zu dieser Untersuchung zur Verfügung stellte.     

Der Einfluss von Papaverin auf Funktionen der Blutplättchen

Summary The adhesiveness and the ADP-induced aggregation of human blood platelets as well as the agglomeration and viscous metamorphosis initiated by thrombin was inhibited by papaverin. The release of biogenic amines and ATP from rabbit blood platelets induced by thrombin or other proteolytic enzymes was diminished. Also eupaverin and ethylpapaverin have an inhibitory effect on the platelet functions.     

Der Einfluss der Epiphyse auf die Lokomotionsaktivität bei Ratten

Summary After pinealectomy adult hypoactive rats show an increased exploratory behavior, whereas adult hyperactive rats show no significant behavioral change. These data are discussed in relation to brain serotonin content.

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Durchgeführt im Rahmen des DFG-Schwerpunktprogrammes Neuroendokrinologie (Vo 135/4).

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Frau Dr. D. Freund, Mainz, danke ich für die Erlaubnis zur Benutzung der Open-Field Anlage, Frau H. Untiedt für technische Hilfe bei der Pinealektomie.