Susceptibility of salmonellae to cephalosporins and to nine other antimicrobial agents

Three cephalosporin-related antibiotics and nine other antimicrobial agents were studied for in vitro effectiveness against 54 recently isolated strains of Salmonella. Minimal inhibitory concentrations determined by the plate dilution method demonstrated the following percentages of resistance: ampicillin, 6%; tetracycline, 13%; streptomycin, 52%; sulfadiazine, 94%; cephaloglycin, 96%; and lincomycin, 100%. No strains were resistant to cephalothin, cephaloridine, chloramphenicol, colistimethate, kanamycin, and polymyxin B. The commonest serotype studied, S. typhimurium, showed the greatest antibiotic resistance, with 21% resistant to ampicillin, 36% resistant to tetracycline, and 71% resistant to streptomycin. Cephalothin and cephaloridine were highly effective in vitro but inhibitory concentrations of 20 to 40 mug of cephaloglycin per ml were required for the majority of Salmonella strains.

Bacteriology of spoilage of fish muscle. IV. Role of protein

Clarified muscle press juice from English sole (Parophrys vetulus) was fractionated by gel filtration into a protein and a protein-free fraction. Upon inoculation with spoilage bacteria, the protein fraction failed to show any signs of spoilage, but the protein-free fraction spoiled according to the usual organoleptic and chemical criteria. Despite its spoilage-resistant qualities, the protein fraction accelerated spoilage of the protein-free fraction when the two were combined. Protein breadkown due to bacterial action was greatest in the unfractionated juice and was least in the protein fraction. No significant proteolysis occurred until after spoilage became evident.

The effect of aldosterone on sodium and potassium distribution in man

Total exchangeable sodium, potassium and bromide space were measured by a triple isotope technique, and antipyrine space, body weight, plasma electrolyte concentrations and urine electrolyte excretion were determined before and after intramuscular injection of 0·5 mg. aldosterone 6-hourly for 6–8 days in nine convalescent men.

After the treatment with aldosterone there were mean increases in body weight of 2·5 kg., 2·5 1. in total body water, and of 3·0 1. in extracellular fluid volume; a slight decrease in intracellular fluid volume was not significant. The mean total exchangeable sodium increased by 463 m-equiv. and the mean cumulative urinary excretion of sodium decreased by 444 m-equiv. The sodium was retained in the extracellular fluid without significant change in exchangeable intracellular sodium. Mean total exchangeable potassium was reduced by 207 m-equiv. while mean cumulative urinary potassium excretion increased by 88 m-equiv. The potassium loss was entirely intracellular.

The main source of error arose from isotope counting. The coefficient of variation of the sample count minus the background exceeded ±3% in 18 out of 150 samples: these results were discarded. Sixteen of the inaccurate counts were due to low concentrations of sodium or potassium in the specimens.

Synthesis of Heliotramide

Both racemates of 4-methoxy-3-hydroxy-2-methylpentane-3-carboxamide are synthesized by reacting isopropylmagnesium chloride with 2-methoxypropionitrile, converting the resulting ketone into the cyanohydrin and hydrolysing to the amide. Comparison with heliotramide shows that the lower melting racemate, m.p. 81-82 �C, is (�)-heliotramide and thus of threo-configuration. The higher melting racemate, m.p. 145-146 �C, is the erythro-amide. Attempts to hydrolyse the amides to the carboxylic acids were unsuccessful. Heliotramide is prepared by heating heliotric acid with urea or by the usual acid chloride-ammonia procedure following protection of the hydroxyl group.