Inhibition of acute effects of hydralazine by an adrenergicβ-receptor blocking agent

Zusammenfassung Die durch Hydralazin verursachte Blutdrucksenkung und Tachycardie am wachen Hund wurde durch Pronethalol antagonisiert. Am narkotisierten Tier änderte Hydralazin die Herzfrequenz nicht, sondern führte zu einer Drucksenkung, die durch Pronethalol verstärkt wurde. Hydralazin steigerte an der narkotisierten Katze den Coronardurchfluss. Dieser Effekt wurde durch Pronethalol aufgehoben. In den verwendeten Dosen hatte Pronethalol auf die gemessenen Grössen keine Eigenwirkung.     

Leukocytenemigrationsförderung durch Antigen-Antikörper-Reaktionin vitro

Summary Pronounced stimulation of leucocytic migration can be produced by addition of low concentrations of different anti-chicken anti-sera to chicken leucocytes migrating in corresponding plasma. The effective substance is present in the precipitate produced by precipitating anti-serum.     

Abhängigkeit der Antiviruswirkung bakterieller Polysaccharide von Behandlungstermin,Behandlungsdosis und Infektionsstärke

Summary The paper analyses the protective or aggravating effect of a purified bacterial polysaccharide in Col.-SK.-Encephalomyelitis and infectious ectromelia in mice, as a function of the method of treatment. Both infections are influenced in a largely similar manner with a typical pattern of variation in the host resistance optimal effects depending on characteristic dose/time relations.     

Myelination in the hippocampus during development and following lesion

Myelin is crucial for the stabilization of axonal projections in the developing and adult mammalian brain. However, myelin components also act as a non-permissive and repellent substrate for outgrowing axons. Therefore, one major factor which accounts for the lack of axonal regeneration in the mature brain is myelin. Here we report on the appearance of mature, fully myelinated axons during hippocampal development and following entorhinal lesion with the myelin-specific marker Black Gold. Although entorhinal axons enter the hippocampal formation at embryonic day 17, light and ultrastructural analysis revealed that mature myelinated fibers in the hippocampus occur in the second postnatal week. During postnatal development, increasing numbers of myelinated fibers appear and the distribution of myelinated fibers at postnatal day 25 was similar to that found in the adult. After entorhinal cortex lesion, a specific anterograde denervation in the hippocampus takes place, accompanied by a long-lasting loss of myelin. Quantitative analysis of myelin and myelin breakdown products at different time points after lesion revealed a temporally close correlation to the degeneration and reorganization pha-ses in the hippocampus. In contrast, electroconvulsive seizures resulted in brief demyelination and a faster recovery time course. In conclusion, we could show that the appearance of mature axons in the hippocampus is temporally regulated during development. In the adult hippocampus, demyelination was found after anterograde degeneration and also following seizures, suggesting that independent types of insult lead to demyelination. Reappearing mature axons were found in the hippocampus following axonal sprouting. Therefore, our quantitative analysis of mature axons and myelination effectively reflects the readjusted axonal density and possible electrophysiological balance following lesion. Received 22 December 2003; received after revision 11 February 2004; accepted 17 February 2004     

«Bindung» eines synthetischen Polypeptides (Hypertensin) an Heparin und Freisetzung des Peptides durch Compound 48/80in vitro

Summary It is shown that a synthetic octapeptide, hypertensin, can be bound to heparinin vitro in a fashion similar to that of histamine. Hypertensin can be liberated from this complex by Compound 48/80.     

Pharmacological characteristics of bradykinin B

Zusammenfassung Die pharmakologischen Effekte (in vitro undin vivo) eines durch Einwirkung von Schlangengift (Bothrops jararaca) auf Rinderplasma erhaltenen, reinen Bradykinins (B) werden beschrieben.     

Eintritt und Mechanismus phagenhemmender Wirkungen

Summary The described antiphage substance: bis-[[4-[4-(3-diethylamino-propylamino)-6-methyl-2-pyrimidyl-amino]-phenyl]]-sulphone tetrahydrochloride tetrahydrate produces its effect not through a direct phagocytic action but indirectly through an inhibition of the phage production. The effect is complete during the whole logarithmic growth phase as long as the phage concentration is kept under the limit, critical for bacteriolysis.     

Profound hypothermia in golden hamsters (Mesocricetus auratus) induced by serotonergic potentiating and noradrenergic inhibiting drugs

Summary Profound hypothermia (6°C) was induced in cold exposed golden hamsters (Mesocricetus auratus) by a combination of drugs that potentiate brain serotonergic activity (fluoxetine and pargyline) and inhibit noradrenergic activity (alpha-methyl-p-tyrosine). Individual drugs and combinations of 2 were ineffective.Acknowledgements. We acknowledge the support of a research grant PCM74-05158 A01 to A.H.M. from the National Science Foundation (USA) and thank Lilly Research Laboratories, Indianapolis, Indiana, for the gift of fluoxetine (Lilly 110140).     

Solid-state NMR determination of the secondary structure of Samia cynthia ricini silk

Silks are fibrous proteins that form heterogeneous, semi-crystalline solids. Silk proteins have a variety of physical properties reflecting their range of functions. Spider dragline silk, for example, has high tensile strength and elasticity, whereas other silks are better suited to making housing, egg sacs or the capture spiral of spiders' webs. The differing physical properties arise from variation in the protein's primary and secondary structure, and their packing in the solid phase. The high mechanical performance of spider dragline silk, for example, is probably due to a beta-sheet conformation of poly-alanine domains, embedded as small crystallites within the fibre. Only limited structural information can be obtained from diffraction of silks, so further characterization requires spectroscopic studies such as NMR. However, the classical approach to NMR structure determination fails because the high molecular weight, repetitive primary structure and structural heterogeneity of solid silk means that signals from individual amino-acid residues cannot be resolved. Here we adapt a recently developed solid-state NMR technique to determine torsion angle pairs (phi, psi) in the protein backbone, and we study the distribution of conformations in silk from the Eri silkworm, Samia cynthia ricini. Although the most probable conformation in native fibres is an anti-parallel beta-sheet, film produced from liquid directly extracted from the silk glands appears to be primarily alpha-helical.