Bernard L. Oser

Physiological Availability of the Vitamins

Publisher Summary This chapter presents the results of nonbiological procedures of vitamin assay do not necessarily reflect available vitamin content. Such methods of analysis are of value in determining total vitamin content; they fail to demonstrate the inter-reactions among the dietary components during digestion or of the influence of the composition of the ration upon vitamin synthesis in vivo. The studies with choline demonstrate that the quantity and composition of the protein in the test ration should be controlled in physiological availability studies based upon urinary excretion responses. It should be possible to assess not only whether vitamins under certain conditions are available for absorption but also to determine the influence of those factors that can be responsible for increasing or decreasing the biological response following the ingestion of a given amount of the vitamin.

Toxicologic studies with branched and linear alkyl benzene sulfonates in rats

Abstract The acute oral toxicities (LD 50 ) and the effects of subacute dietary intake of both branched (ABS) and straight-chain (LAS) alkyl benzene sulfonates have been determined. For the ABS the LD 50 is 0.52 g/kg, and for the LAS, 0.65 g/kg, when the samples are administered in water dispersion to rats. The difference between these values is not statistically significant. Weanling rats were fed ABS or LAS mixed with the diet to give dosages of 0.05 and 0.25 g/kg/day for 12 weeks. When the animals had reached maturity, these dosages were provided by dietary concentrations of 1000 and 5000 ppm, respectively. The rats developed normally and showed no changes related to ingestion of the test material in any of the parameters examined, with the possible exception of a slight increase in liver weight. This effect was seen in both sexes at the higher dosage of ABS, but only in the females of the LAS group at 5000 ppm in the diet. No accompanying morphologic changes were seen in these livers on microscopic examination.

Long-term and multigeneration toxicity studies with cyclohexylamine hydrochloride

Cyclohexylamine (CHA), the metabolite of cyclamate produced in varying degree by gastrointestinal microorganisms, was subjected to a 2-year multi-generation feeding study in rats, at dosages of 15, 50, 100, and 150 mg/kg/d. Observations included growth, feed efficiency, clinical and hematological tests, reproduction, teratology, mortality and gross and microscopic pathology. Rats from the first litters of each generation from F0 through F4 were mated to produce the next succeeding generation. Those from the second litters of F1 through F4 were also mated, half the dams being delivered by hysterotomy for teratological examination, while litters from the other half were raised to maturity. Except for some non-progressive growth retardation in the higher dosage groups, due to lower food consumption, the physical and clinical observations in the test groups fell substantially within normal limits and were not significantly different from the untreated controls. Reproduction rates were normal in all groups but at the higher dosages the size of the litters and their weaning weights were slightly reduced. At the 150 mg/kg level, histopathological examination revealed mucosal thickening of the bladder walls and evidence of renal calcification; however, no bladder tumors were seen, such as occurred in the chronic feeding study in which rats received 2500 mg/kg of a cyclamate: saccharin (10 : 1) mixture. A significantly higher incidence of testicular atrophy, characteristic of aged rats, was observed in the F0 group at the highest dosage level; however, these males continued to be fertile, in two cases up to 6 consecutive matings.

Toxicologic studies of petrolatum in mice and rats

Abstract The present studies were undertaken as a basis for determining the status of food grade petrolatum as a food additive under the terms of the Food Additives Amendment of 1958. The investigations of the petrolatum included 2-year rat feeding studies and single subcutaneous injections in mice followed by observation over an 18-month period. Previous work and the considerations leading to regulatory interest in the potential carcinogenicity of paraffin hydrocarbons have been reviewed in the extensive report on the toxicity of petroleum waxes by Shubik et al. (1962). Three specific color grades of petrolatum which met either USP XVI or NF XI (White or Yellow Petrolatum) were selected to represent the range of degrees of decolorization of petrolatum commonly used as direct food additives, or which may be incorporated in foods as an indirect additive, incidental to its use in processing.

Carcinogenicity study of carbarsone

A study is described in which diets containing 500 and 1000 ppm of carbarsone (p-ureidobenzene-arsonic acid) were fed to large groups of rats for 104 weeks, and 2000 ppm for 72 weeks followed by a 32-week withdrawal period. The lower dosages caused no changes in growth or efficiency of food utilization, and no deviation from normal hematologic, blood chemical, and urine parameters, or in tissue morphology. The 2000-ppm dose depressed growth and caused marked intestinal inflammatory reactions with the sequelae eventually resulting in death. When this highest dose was withdrawn from the diet of surviving rats at 72 weeks, they recovered completely. There were no indications of a carcinogenic potential of this compound at any dosage. Acute experiments in dogs given carbarsone in massive intragastric doses showed that two-thirds of the urinary arsenic excretion was in the form of arsanilic acid and one-third as the original compound.