Characterization of prehistoric flint mine products

Trace element analyses of flint show statistically valid differences between products of major British and European Neolithic flint mines.     

Plasmids of the same Inc groups in Enterobacteria before and after the medical use of antibiotics

Conjugative plasmids were common in enterobacteria isolated before the medical use of antibiotics. Plasmid F of Escherichia coli K-12 was one example and we identified others in over 20% of a collection of strains isolated between 1917 and 1954, the Murray collection. In the past 25 years, conjugative plasmids encoding antibiotic resistances have become common in bacteria of the same genera as those of the Murray Collection--Salmonella, Shigella, Klebsiella, Proteus, Escherichia. The present study was made to show whether the 'pre-antibiotic' plasmids belonged to the same groups, as defined by incompatibility tests (Inc groups), as modern R plasmids. Of 84 such plasmids established in E. coli K-12, none with antibiotic resistance determinants, 65 belonged to the same groups as present resistance (R) plasmids. Thus the remarkable way in which medically important bacteria have acquired antibiotic resistance in the past 25 years seems to have been by the insertion of new genes into existing plasmids rather than by the spread of previously rare plasmids.     

Histochemistry of some trout respiratory muscles

Summary A histochemical study has been made of the main cranial muscles which produce ventilation movements of the rainbow trout. It is shown that a greater proportion of red(aerobic) fibres is present in those muscles known to be active during shallow ventilation than those which become active at greater ventilation volumes. An ordered recruitment of red, pink and white fibres within these muscles is also likely.This work was carried out when I.A. Johnston was holding an NERC Post-Doctoral Research Fellowship (1973–75).     

Two new short-acting non-depolarizing neuromuscular blocking agents

Résumé Le chlorure de 1,1-octaméthylène et le méthylsulfate de 5,5-octaméthylènebis ont chez le chat un effet de blocage neuro-musculaire non dépolarisant, de courte durée. Les comparaisons faites avec des analogues voisins suggèrent que l'activité de ces composés est influencée par le degré d'empêchement stérique autour des atomes d'azote quaternaire. Les composés inhibent les acétylcholinestérases et s'opposent à des degrés divers aux effects muscariniques de l'acétylcholine.     

The comparative enhancement of the depressant action of alcohol by eight representative ataractic and analgesic drugs

Zusammenfassung Eine Methode zur Messung der Potenzierung von Tranquilizern und Analgetika auf Äthanoldepression wird beschrieben. Unbeweglichkeit von Mäusen wird als Kriterium der Depression genommen. Die fünf Tranquilizer, die gebraucht wurden, haben Äthanol in verschiedenen Graden potenziert. Von den drei analgetischen Drogen hat Morphin, nicht aberd-Propoxyphen und Codein, Äthanolnarkose potenziert.

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This study was supported (in part) by a P.H.S. research grant AC-20 from the Division of Accident Prevention, Bureau of State Services, Public Health Service.