Effect of histones from brain on DNA-synthesis in vitro

The results of these experiments demonstrate that histones from brain inhibit the replication of DNA in vitro. A similar effect is observed with polylysine or polyarginine. The reversion of inhibition by polyglutamic acid or acidic proteins is completed in all cases except when the DNA is previously complexed with histones, polyarginine or polylysine. This suggest that histones masking of DNA towards the polymerases involves electrostatic forces.     

Effect of pancreatic polypeptide on DNA-synthesis in the pancreas

Summary Bovine pancreatic polypeptide increases DNA-synthesis in the rat pancreas; no effect is observed in stomach (oxyntic area), duodenum or liver. BPP neither augments or inhibits the trophic action of cholecystokinin.Acknowledgment. Pure pancreatic polypeptide was donated by Dr. R. E. Chance (Lilly Research Laboratories, Eli Lilly and Co., Indianapolis, Ind, USA). G. R. Greenberg is supported by a Fellowship of the Medical Research Council of Canada.     

Effect of tranexamic acid on progress of experimental tumours and on DNA-synthesis

Summary The fibrinolytic inhibitor tranexamic acid affects certain experimental tumours; it prolongs survival (Lewis lung adenocarcinoma), decreases tumour weight (C3H breast carcinoma), and inhibits ascitic production (AH 130 rat hepatoma). However, it does not significantly influence DNA-synthesis in cell suspensions prepared from the same tumours.Acknowledgment. This study was supported by grants from Malmö Allmänna Sjukhus and the Swedish Medical Research Council (B79-17X-04523-05B).     

Effect of sulpiride on oxygen uptake by rat's brain tissue in vitro

Resumen El Sulpiride in vitro a la concentración de 1×10^–2 M disminuye el consumo de Oxígeno en cortes de cerebro de rata. El exceso de potasio o ausencia de calcio en el medio de incubación, no modifican este efecto. En homogeneizado de cerebro total, unicamente a la concentración de 1×10^–2 M deprime el consumo de oxígeno. A las concentraciones 1×10^–3 y 1×10^–4 M no modifica el consumo de oxígeno en cortes ni homogeneizados de cerebro.     

Effect of Ketamine hydrochloride on oxygen and glucose uptake by brain tissue in vitro

Resumen El clorhidrato de Ketamina (1×10^–3 M y 1×10^–4 M) incrementa el consumo de oxigeno de cortes de cerebro de rata incubados en Krebs-Ringer fosfato conteniendo 5 mM ó 100 mM de potasio. La droga no modifica el consumo de oxigeno de homogeneizado de cerebro total.     

The effects of various agents in vitro on homocarnosine-carnosine synthetase from rat brain

Summary The present paper reports the first evidence that homocarnosine-carnosine synthetase from rat brain requires free sulfhydryl groups for activity. The activity of the synthetase can be stabilized by dithioerythritol and inhibited strongly by Cu²⁺, Cd²⁺, Hg²⁺, Zn²⁺, and to a lesser extent by Ca²⁺, Ni²⁺, Li, chlorpromazine, -methyl DOPA and norepinephrine at the concentrations tested.Acknowledgment. This work was supported by United States Public Health Service Grant No. NS-06137.     

The fractionation of arginine-rich histones from calf thymus

Zusammenfassung Die argininreiche Fraktion des Kalbsthymushistons (Fraktion 2a) wurde in zwei Komponenten zerlegt. Zusammensetzung und elektrophoretische Trennung der Komponenten (F2a_I und F2a_II), ebenso die Eigenschaften eines neuen, lipidgebundenen, serinreichen Histons wurden beschrieben.     

Effect of serum from tumor-bearing mice on the in vitro migration of thymocytes

Résumé La migration in vitro, hors de tubes capillaires, des thymocytes de souris est plus importante en présence du sérum de souris porteuses d'une tumeur syngénique transplantée chimio-induite qu'en présence de sérum normal. Ce phénomène, qui est fonction du poids de la tumeur, pourrait être en rapport avec l'involution thymique accompagnant la croissance tumorale.     

A basic protein from bovine brain that co-precipitates with tubulin in vitro

A 193 kDa protein consisting of 58 kDa subunits, which has pI values of 8.50 and 8.65, was purified from bovine brain cytosol. It formed heavy precipitates with tubulin, and the molar ratio of tubulin dimer to this protein in the precipitate was 3.2. In contrast to microtubules containing ordinary microtubule-associated proteins, these complexes remained stable against cold and 1 mM CaCl2.     

A basic protein from bovine brain that co-precipitates with tubulin in vitro

A 193 kDa protein consisting of 58 kDa subunits, which has pI values of 8.50 and 8.65, was purified from bovine brain cytosol. It formed heavy precipitates with tubulin, and the molar ratio of tubulin dimer to this protein in the precipitate was 3.2. In contrast to microtubules containing ordinary microtubule-associated proteins, these complexes remained stable against cold and 1 mM CaCl₂.Acknowledgments. This work was supported in part by a Grant-in-Aid for Scientific Research from the Ministry of Education, Science and Culture of Japan.     

Effects of histones on embryonic cells

Zusammenfassung Der Einfluss vom Kalbsthymus Histon (CTH) und seines diazotierten Derivatives (DCTH) auf Vitalität und Zelldifferenzierung verschiedener Gewebe des Hühnerembryos wurde geprüft. Die LD₅₀ für CTH wurde bei 25µg/ml der Zellsuspensionen festgestellt. Es wurden keine bedeutenden Änderungen in der Differenzierung der embryonalen Gewebe in Kulturen bei sublethalen Konzentrationen gefunden.     

Effect of nicotine on the mobilization of free fatty acids from adipose tissue in vitro

Zusammenfassung In-vitro-Versuche mit Fettgewebe von Ratten zeigten keine direkte Wirkung des Nikotins auf die Freisetzung nicht veresterter Fettsäuren. Wurde den Tieren Nikotin verabreicht, bevor sie getötet wurden, so konnte nach Inkubation des Fettgewebes ein signifikanter Anstieg der Lipolyse festgestellt werden. Diese Beobachtung stützt die Auffassung, dass die Mobilisierung freier Fettsäuren durch Nikotin über eine sympathoadrenale Stimulierung erfolgt.     

Activation by S-adenosylhomocysteine of norepinephrine and serotonin in vitro uptake in synaptosomal preparations from rat brain

Summary S-Adenosylhomocysteine (10^–7–10^–5 M) activated norepinephrine (NE) and serotonin (5HT) in vitro uptake in synaptosomal preparations from rat brain, but did not affect dopamine (DA) uptake. When administered to rats (7 mg/kg i.p.), it had the same effect on in vitro NE and 5HT uptake. It did not affect NE and 5HT release.Work achieved within the frame of the research contract institut Mérieux., Institut National des Sciences Appliquées.     

Effect of ethanol on taurine concentration in the brain

Summary The taurine concentration in the brain was decreased in ethanol-dependent rats, but returned to normal soon after withdrawal of ethanol. It was not affected by acute ethanol administration.This research was supported by a grant from the Taisho Pharmaceutical Co., Ltd., Tokyo.     

Effect of brain lesions on hypothalamic noradrenalin in rats

Résumé Des lésions bilaterales, localisées par stéréotaxie dans la région de l'hippocampe chez le Rat, produisent au bout de 20 jours une diminution significative de la concentration en noradrénaline de l'hypothalamus. Si les rats sont sacrifiés 10 jours seulement après la lésion, il n'y a pas de modifications dans cette concentration. Le contenu en noradrénaline de l'hypothalamus est légèrement réduit par des lésions thalamiques, mais n'est pas modifié par des lésions faites au niveau du cortex cérébral, de l'amygdala, de l'habénula, du corpus callosum, et du bulbe olfactif.

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Research Associate. Consejo Nacional de Investigaciones Científicas.     

Effect of ecdysone on glutamic decarboxylase in rat brain

Résumé Nous avons étudié l'effet que produisait l'ecdysone, une hormone de la mue chez les insectes, sur l'activité de l'acide glutamique decarboxylase du cerveau de rat. Nous avons observé que l'activité de cet enzyme augmentait de façon significative chez les rats traités par cette hormone.     

Effect of lithium on brain aconitase activity

Résumé Nous avons déterminé l'activité spécifique de l'aconitase cérébrale des souris après une période de 108 jours de traitement avec du lithium (Li₂CO₃). Une inhibition significative de l'enzyme à été observée. D'autre part, nous n'avons trouvé in vitro aucun effet du Li₂CO₃ sur l'aconitase cérébrale.

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R. R. A. was supported by a research grant from the Conselho Nacional de Pesquisas (National Research Council of Brasil).     

Effect of bromocriptine on gonadal ornithine decarboxylase in vitro

Summary The alterations in ornithine decarboxylase activity in response to in vitro treatment with bromocriptine suggest the possible direct action of the drug on gonads.     

The specificity of histones in nucleated erythrocytes

Riassunto Dagli eritrociti del pollo, dellaRana cateasbeiana e del pesceCaranx hippos sono stati isolati gli istoni nella ipotesi che gli eritrociti forniti di nucleo contengano una frazione di istone funzionante come repressore permanente della sintesi degli acidi nucleici. Detti istoni sono stati frazionati ed analizzati nella loro composizione in amino-acidi. In tutte e tre le speci su menzionate è stata trovata una frazione relativamente ricca in lisina, arginina, alanina, e serina che è stata denominata F2c. L'assenza di detta frazione negli altri tessuti incluso il midollo osseo indica che la frazione F2c può costituire un repressore genetico permanente.

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This investigation was supported by the U.S. Public HEalth Service Grant No. CA-07746, American Cancer Society Grants E-388 and IN-43-F2, and by the Robert A. Welch Foundation Grant G-138.