Henry E. Paul

Resistance and Cross Resistance of Bacteria to Nitrofurans

Summary (1) Bacteria can develop only a limited resistance to the nitrofurans in vitro. On the basis of a bacterial cross resistance study of a series of eighteen nitrofurans, it was found that the compounds investigated could be divided into two classes. The second class differs in chemical structure by having a carbon atom between the carbonyl group and the terminal group of the nitrofuran side-chain. Bacteria becoming resistant to the first class are reciprocally cross resistant to all members of this class but remain susceptible to nitrofurans of the second class. (2)Bacteria in which resistance was developed to chloramphenicol or to aureomycin remain susceptible to the nitrofurans. The converse is also true.

The effect of mineral oil on food utilization II. Changes of beta-carotene in mineral oil

On the basis of the experiments reported here, stereoisomerization of beta-carotene is believed to occur both in vitro and in vivo in the presense of mineral oil. The lower biological activity of the stereo-isomers may account in part for the deleterious action of mineral oil on carotene utilization.

THE EFFECT OF MINERAL OIL ON FOOD UTILIZATION I. CALORIC VALUE OF FOOD

Food consumption records and fecal weight data have been obtained on albino rats receiving diets with and without mineral oil. These data indicate that, at the levels of mineral oil studied, no caloric loss of food is experienced with the ingestion of mineral oil since: The levels of mineral oil studied were comparable on the basis of food consumption to doses of medicinal mineral oil commonly prescribed for the relief of constipation in humans.

The effect of mineral oil upon fecal consistency, fecal bulk, and velocity of gastro-intestinal transport

Objective studies have been conducted on experimental animals to determine the results of mineral oil ingestion which may explain its value as a laxative. Laboratory methods have been described.