A study of the mechanism of polymyxin M inactivation

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Antigénicité et pouvoir immunogène des toxines extraites des venins d'Elapidae et d'Hydrophiidae

Summary In this article the results are reported of recent experiments concerning the antigenicity and the immunogenic properties of some basic toxic proteins recently extracted from snake venoms. A serological classification of these substances is proposed. 3 groups have now been determined. As most of the low molecular weight proteins (<10.000) the immunogenicity of the toxin ofNaja nigricollis, taken as an example, is poor. The influence of polymerization of this toxin, and the adjuvant effect of the Freund mixture on the production of specific antibodies, are described. By affinity chromatography, using Sepharose 4B as a carrier, antibodies against this toxin were separated from the other proteins of the antiNaja nigricollis horse immune-serum. They belong to the IgT immunoglobulins. By the same technique, when erabutoxin a fromLaticauda semifasciata is covalently linked to the Sepharose, antibodies reacting with both this toxin and the toxin were separated from the same immuneserum. This confirms that an immunological relationship exists between the toxin of an Elapidae:Naja nigricollis, and the erabutoxin a of an HydrophiidaeLaticauda semifasciata.     

The benzilic acid rearrangement of 3α,17β-Diacetoxy-11-hydroxy-12-oxo-5β-androst-9(11)-ene

Zusammenfassung Die Bildung von 11-Carboxy-3, 11, 17-trihydroxy-13-C-nor-5-androstan 11a,17-Lakton aus 3, 17-Diacetoxy-11-hydroxy-12-oxo-5-⁹(11)-androsten wird beschrieben. Der Mechanismus und die Stereochemie dieser Umwandlung (Retro-Aldolkondensation und Benzilsäureumlagerung) wird diskutiert.     

Regioselectivity in the oxidative deamination of 2-methyl-1,4-diaminobutane catalyzed by diamine oxidases

Summary Diamine oxidase from pea seedlings (PDAO) catalyzes the oxidation of 2-methyl-1,4-diaminobutane in a regioselective fashion, whereas diamine oxidase from pig kidney (KDAO) shows no regioselectivity for the same reaction.This work was supported by Ministero della Pubblica Istruzione. We thank Prof. A. Fiecchi and Prof. S. Ronchi for many helpful discussions.     

Phasic hippocampal activity during paradoxical sleep in the rat: selective suppression after diazepam administration

Summary The effects of diazepam on tonic (T) and phasic (P) components of the paradoxical-sleep hippocampal theta rhythm were studied in the rat. Results show that diazepam, a benzodiazepine analogue known to interfere with the putative neurotransmitter -aminobutyric acid (GABA) in the mammalian central nervous system, selectively abolishes P. They confirm previous data according to which sedative/anaesthetic drugs cause, an apparent dissociation of T and P of the paradoxical-sleep hippocampal theta rhythm. Moreover, they suggest a possible involvement of GABA in the neurochemical mechanisms underlying P in the rat.     

The participation of kinins in the pathogenesis of early disturbances in the skin capillary permeability in localβ-ray irradiation

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Suppression of antibody formation against sendai virus in the SV40 and adenovirus 16 infected hamsters

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Magnug reflexex of the chest musculature in man

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Some functional characteristics of the electroreceptors (the ampullae of lorenzini) of elasmobranchs

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The effect of chloramphenicol analogs on protein biosynthesis in a cell-freeEscherichia coli B system

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Laboratory of Biological Investigations.

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Laboratory for Chemistry of Antibiotics.     

Polyribosome patterns in EMC-virus infected Krebs-2 cells and cell extracts

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Isoforms of baker's yeast transketolase

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Accumulation of ribonucleoprotein structures in chronically virus-infected cells

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Potential juvenile hormone analogues containing piperidine ring: Synthesis and biological assay on insects

Summary Some compounds containing piperidine rings have been synthesized, and submitted to biological tests on insects for their hormonal activity on pupae ofTenebrio molitor L. andBombyx mori L. Some of them display a hormoneanalogue or toxic activity.The editors do not hold themselves responsible for the opinions expressed in the authors' brief reports. — Les auteurs sont seuls responsables des opinions exprimées dans ces brèves communications. — Für die Kurzmitteilungen ist ausschliesslich der Autor verantwortlich. — Per le brevi comunicazioni è responsabile solo l'autore. — . — Solo los autores son responsables de las opiniones expresadas en estas comunicationes breves.This research has been supported by the Italian National Research Council (CNR) special ad hoc program Fitofarmaci e Fitoregolatori, Subproject. 7.Acknowledgments. We thank Prof. G. Jommi for helpful discussions related to this and previous articles on the same subject.     

Two cell-free systems for the assay of virus-specific polymerase

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X-ray research for polycrystals. The formation geometry of instrumental width of the diffractional line at the investigation of the polycrystals in the translucent X-rays

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Topochemical approach to the structure-activity relation. Retroenantio-Gly5,10-gramicidin S

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Changes in the lumen of coronary vessels under oligemic hypotension

Conclusions The decrease of circulating blood volume, resulting in oligemic hypotension, may evoke in anaesthetized cat the active constrictory coronary vessel responses of 2 types, one occuring immediately after start of the hypotension and the other having a significantly prolonged latency.

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Reactive synthesis of DNA and mitotic division in atrial heart muscle cells following ventricle infarction

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Do the respiratory muscles and lung receptors influence the respiratory sensitivity to CO2?

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