Recent Advances in Nutrition and Metabolism

Abstract

A SMALL monograph entitled "Present Knowledge in Nutrition" has been published recently.1 This should prove a most useful reference ; sections dealing with calories, protein, fat, carbohydrate, minerals, and vitamins are included. VITAMIN A Cama and associates * reported further studies of the characteristics of vitamin A and related compounds. Kaiser and Kagan 6 have described a technique for the determination of vitamin A in feces.Prolonged administration of quinacrine (Atabrine) to rats was found to result in damage to the liver and impairment of the ability of this organ to store vitamin A. Absorption of vitamin A and carotene was depressed by the drug.7The administration of excessive amounts of vitamin A to rats and other animals accelerates the growth and maturation of epiphyseal cartilage cells and the remodeling process which accompanies bone growth. Such effects are suggestive of hormonal action, possibly that of the anterior pituitary. However, studies by Wolbach and Maddock 8 in hypophysectomized rats have shown that these effects occur in the absence of the pituitary and in spite of marked atrophy of the adrenal glands. Similar effects have been observed upon the addition of excessive amounts of vitamin A to the medium containing tissue culture of bone from chick embryos.9 The changes observed in tissue culture are qualitatively similar to those seen in animals made hypervitaminotic by feeding large amounts of vitamin A.f The use of tissue culture techniques appears to offer distinct advantages in the study of the effects of vitamin A upon tissues.14 An unusual case of vitamin A deficiency in a 5 J^-month-old infant was reported by Cornfeld and Cooke.15 Facial palsy and increased intracranial pressure observed in this patient might possibly be attributed to compression of tissues of the growing central nervous system by failure of normal growth of the axial skeleton, which has been observed in various mammalian species and, more recently, in the chicken and duck.| weeks. Definite beneficial effects of this therapy upon localized conjunctival thickening, blepharoconjunctivitis, and "toad skin" were observed. Follicular hyperkeratosis of the forearms persisted in five of eight patients, and improvement in dark adaptation was observed in only 4 of 17 subjects. Kaser and associates 1T reported that patients with a sprue-like syndrome showed no increase in serum vitamin A levels after oral administration of the vitamin given in either the ester or the alcohol form. Patients with chronic pancreatic disease showed no change in serum levels of the vitamin after administration of its ester form, but they were found to have an increase in serum vitamin A after administra¬ tion of the alcohol form.Steigmann and co-workers 18 confirmed the previously reported interference with absorption of vitamin A by mineral oil given close to mealtimes. However, the usual therapeutic dose (30 cc.) of the oil given at bedtime was without effect upon plasma vitamin A levels.Kagan and Kaiser 19 found high concentrations of v...