A study of the mechanism of polymyxin M inactivation

.I.NH₄OH , N N - - ,-. , .     

A comparison between the photoreactivity of some furocoumarins with native DNA and their skin-photosensitizing activity

Riassunto È stata determinata la fotoreattività con DNA nativo di un gruppo di furocumarine per irradiazione a 365 nm. I valori ottenuti sono risultati in accordo con quelli di attività fotosensibilizzatrice cutanea posseduti dalle stesse sostanze.     

Shwartzman phenomenon without endotoxin preparation

Zusammenfassung Kasein, Pepton bzw. Baktokasiton wurde als präparierende Erstinjektion für lokalisiertes Shwartzman-Phänomen an Kaninchen verwendet. Nach provozierender i.v. Endotoxininjektion kommt es zum typischen Shwartzman-Phänomen. Da die verwendeten Substanzen Chemotaxis von Leukozyten verursachen, ist anzunehmen, dass die an Stelle der präparierenden Injektion angesammelten Leukozyten in der Ausbildung des Shwartzman-Phänomens eine vorwiegende Rolle spielen.     

Radiation induced avoidance behavior transfer by brain extracts of mice

Zusammenfassung In «naiven» Mäusen werden Verhaltensveränderungen nach Injektion kleiner Mengen von Gehirnmaterial aus Saccharin bevorzugenden und röntgenbestrahlten Mäusen beobachtet. Es trat Vermeidung der Saccharinlösung ein, und zwar ähnlich wie sonst in «trainierten», Saccharin bevorzugenden Tieren nach der Bestrahlung.     

Theory agrees with experimental thermal denaturation of short DNA restriction fragments

Experimental melting transitions of several natural DNAs of known nucleotide sequences have recently been obtained. The differential melting curves of these DNAs-phi X174 DNA, fd DNA and SV40 DNA-all show distinctive sets of peaks or fine structure. Theoretical melting curves calculated from the sequences and a few a priori parameters have not accurately predicted the experimental transitions. Although calculated fine structure resembled experimental curves in some cases, the characteristic features of a DNA's differential melting curve could not generally be produced. Azbel and Gabbarro-Arpa et al. have recently obtained good agreement between calculated and experimental curves using a different theoretical approach-only ground-state configurations of DNA were considered for temperatures inside the transition region. Their results suggest that the basic model of DNA melting, common to all theoretical approaches, is accurate. We have used here an exact theoretical approach to calculated melting curves of four DNA restriction fragments of 95-301 base pairs containing the lactose promoter region (Fig. 1). Theoretical curves agree very well with the experimental transitions published by Hardies et al. and obtained in this laboratory.     

Dimethyloxarsylethanol from anaerobic decomposition of brown kelp (Ecklonia radiata): A likely precursor of arsenobetaine in marine fauna

Summary The novel arsenic compound, dimethyloxarsylethanol, has been isolated from anaerobically incubatedEcklonia radiata. It is proposed that this compound has a key position in the biosynthesis of arsenobetaine.C, H microanalyses were performed by the Australian Microanalytical Service.     

Inhibition of neurotensin (NT)-induced glucagon release by [D-Trp11]-NT1

Summary A synthetic analog of neurotensin (NT), [D-Trp¹¹]-NT, antagonized NT-induced hyperglucagonemia and hyperglycemia, and also NT-induced glucagon release from pancreatic islets in rats.This work was supported in part by a grant from the Imanaga Medical Research Foundation, Nagoya, Japan. Address for reprint requests: M.U., Department of Surgery, National Nagoya Railway Hospital, Taiko 1-chome, Nakamura-ku, Nagoya 453, Japan.