Modification of the action of pentagastrin on acid secretion by botulinum toxin

Summary I.v. botulinum toxin after 60–90 min abolished the dose-response relationship between pentagastrin and gastric acid secretion in anesthetized rats and guinea-pigs. The toxin reduced but did not abolish the acid stimulatory effect of histamine. As expected, the acid response to vagal stimulation was abolished and that to methacholine in rats was unaltered by the toxin.Acknowledgment. We are grateful to the generosity of Dr Edward J. Schantz, Food Research Institute, University of Wisconsin, for the botulinum toxin used. — This research was supported by NIH grant 1 RO1 AM 17125, The Secretion of Pepsin.     

Sperm activation inBalanus balanoides (Crustacea: Cirripedia)

Summary Ammonium ions alone will activate both vesicula and inseminated spermatozoa ofBalanus balanoides. Maximum activity, however, occurs when inseminated spermatozoa are treated with the blood and oviducal gland fluid ofB. balanoides.Acknowledgments. I should like to thank Mr K. White for the ammonia determinations and Prof. D. J. Crisp and Dr P. A. Gabbott for useful discussions.     

Radioimmune, radiobinding and HPLC analysis of 2-5A and related oligonucleotides from intact cells

The enzyme (2-5A synthetase) which synthesizes ppp(A2'p)nA where n=2 to 4 (collectively referred to as 2-5A) is widely distributed in a variety of cells and tissues in amounts which increase response to interferon and vary with growth and hormone status. 2-5A activates a nuclease which inhibits protein synthesis. The non-phosphorylated 'core' of 2-5A ((A2'p)nA, n=2 to 4) can inhibit DNA synthesis and cell growth. Here we describe convenient and sensitive radioimmune (RI) and radiobinding (RB) assays for core and 2-5A. In combination with more satisfactory high performance liquid chromatography (HPCL) methods using reverse-phase C18 columns, these assays have been used to detect core and 2-5A in crude extracts from interferon-treated cells. The novel 2-5A synthetase products NAD2'p5' A2'p5'A and A5'p45'A2'p5'A2'p5'A (ref. 13), which can also be detected using the RB assay, were not found in significant amounts. The natural occurrence of core has not been described previously.     

1,2-di-n-butylhydrazine dihydrochloride carcinogenesis in mice

Summary A solution of 0.0625% 1,2-di-n-butylhydrazine dihydrochloride (1,2-DBH) was given continuously in the drinking water of 6-week-old randomly bred albino Swiss mice for the remainder of their lives. The treatment gave rise to tumors of the lungs, lymphoreticular tissue and kidneys.     

Nicotinamide administration alters the activities of hepatic microsomal mixed function oxidases

Summary Systemic action of nicotinamide significantly alters the activities of hepatic drug metabolizing enzymes. Male rats injected with nicotinamide have reduced levels of cytochrome P450, demethylases and aniline hydroxylase. The changes appear to be sex-dependent since in the case of female rats activities of p-nitroanisole-o-demethylase and aniline hydroxylase are enhanced whereas cytochrome P450 content remains unaltered.Authors gratefully acknowledge the encouragement given by Professor A.S. Paintal during the course of this investigation. One of us (J.K.B.) is grateful to the Council of Scientific and Industrial Research, New Delhi, for the award of a research fellowship.     

Pressor and oxitocic-like effects of angiotensin affected by aldosterone pretreatment in guinea-pigs

Résumé Les auteurs examinent l'augmentation de l'action de l'angiotensine sur la pression carotidienne et sur la contraction utérine chez des animaux traités avec de l'aldostérone. Ils pensent aussi que le traitement conditionne le développement du phénomène taquiphylactique de l'angiotensine.     

A new method for measuring guanidine in uremia

Riassunto Si descrive un metodo per la determinazione della guanidine nei liquidi biologici e si rileva che essa aumenta nel siero uremico fino a 30 volte la norma (valore medio normale: 1.41±0.49 g/100 ml) e che nei cani uremici la concentrazione muscolare è di quasi 3 volte superiore a quella plasmatica. La eliminazione urinaria non è diversa fra normali ed uremici: 382±221 e 459±229 g/24 h, rispettivamente.

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Aknowledgments. This investigation was supported by Public Health Service, Research Contract No. PH-43-68-1466.