A study was conducted to characterize the molecular species of retinol-binding protein (RBP) isolated from the urine of rabbits chronically poisoned with cadmium. The RBP species, identical with regard to both molecular size (approximately 20, 000) and immunoreactivity, were separated into four fractions by means of polyacrylamide gel electrophoresis (PAGE), which yielded two holo-RBP (H2 and Hl) and two apo-RBP (A2 and A1) species. The urinary excretion ratio of these fractions (H2:Hi:A2:Al) was found to be about 70:6:21:3. No distinct difference of amino acid composition between holo and apo-RBP was observed. An additional species of apo-RBP (designated An) was also isolated from the aged holo-RBP (H2) by isoelectric focusing in gel. Using the separated molecular species of rabbit RBP as well as of human RBP, their interactions with human prealbumin (PA) were examined both by human PA-Sepharose affinity chromatography, and by gel filtration on Sephadex G-100 after in vitro incubation of the RBP with human PA. Purified rabbit holo-RBP exhibited almost the same binding ability to human PA as did human RBP. Retinol within RBP molecule enhanced the affinity to PA, presumably through the change of tertiary structure, although the presence of retinol was not essential for the protein-protein interaction.
Since γ-hydroxybutyric acid (GHB) is known to be an effective anesthetic adjuvant in animal and a natural metabolite of succinic semialdehyde (SSA), the effect of SSA and GHB on the convul sive action of vitamin B6 antagonists was studied using the onset of seizure as a parameter. The administration of SSA and GHB to mice protected them against the convulsive action of B6 antagonist, such as castrix (2-chloro-4-dimethyl-6 methylpyrimidine), thiosemicarbazide, or penicillamine. The anticonvulsant effect of SSA seems to be due to an increase in brain levels of GHB converted in vivo from SSA.
Effects of choline fortification and various dietary protein levels on liver lipid content in pyridoxine-deficient rats were studied. Choline fortification did not prevent the accumulation of liver lipids in pyridoxine-deficient rats. Considerable accumulation of liver lipids was observed in the 70% casein pyridoxine-deprived group. Reducing the protein level in the diet decreased the extent of lipid accumulation. A highly negative correlation was found between liver lipid content and liver GPT activity, indicating that the fatty infiltration of the liver may be intimately related to the pyridoxine deficiency state. The time course of fatty liver induction upon feeding of a 70% casein pyridoxine-deficient diet was also studied. The liver lipid content increased gradually and reached the highest value by the third week with a concomitant decrease in food intake. Effect of change of dietary compositions on fatty liver caused by 70% casein pyridoxine-free diet was examined. Feeding of a 70% casein pyridoxine-supplemented diet or a 20% casein pyridoxine-free diet caused decreases in the liver lipids.
A modified procedure for the purification of 5, 6-trans-D3 from a reaction mixture of vitamin D3, with iodine and its biological activity in sham-operated and anephric rats are described. When a solution of vitamin D3, in n-hexane was reacted with small quantities of iodine under influence of visible light, the reaction mixture gave four or five spots, including vitamin D3 and 5, 6-trans-D3 on a thin-layer chromatogram. After purifying the mixture by alumina column chromatography, a colorless oil from the separated 5, 6-trans-D3 fractions was crystallized from n-hexane and snow white crystalline 5, 6-trans-D3 was obtained. The purification method was thought to be better than the previously reported methods (14-16) because it gave good yield without the procedure of esterification using expensive p-phenylazobenzoyl chloride. A dose of 25 μg of 5, 6-trans-D3 obtained thus gave significant elevation on intestinal calcium transport in both sham-operated and anephric rats, whereas the dose did not give positive effects on serum calcium levels in anephric rats. Serum phosphorous levels were extremely elevated by nephrectomy, but in both sham-operated and anephric rats they were unaffected by the administration of 25 μg of 5, 6-trans-D3.
The addition of glyoxal, a trapping agent, caused simultaneously the accumulation of a green fluorescent compound and the inhibition of riboflavin formation in non-growing cells of Eremothecium ashbyii. The fluorescent compound purified was identified as 8-ribityllumazine from the results of spectrophotometric and fluorometric analyses. Accordingly, the fragment, except for the glyoxal portion on the 8-ribityllumazine molecule, 4-ribitylamino-5-amino-2, 6-dihydroxypyrimidine, is believed to be an intermediate in the riboflavin biosynthetic pathway.
Ascorbic acid (vitamin C) prevented diphtheria toxin from inhibiting the incorporation of [U-14C]-alanine into trichloroacetic acid precipitable material in HeLa cells. Ascorbic acid did not exhibit an effect on the adenosine diphosphate-ribosylation of amino acyl trans ferase II nor did it separate fragment A from fragment B in “nicked” toxin. A non-specific reducing agent, para-methylaminophenol sulfate, exhibited an effect on HeLa cells very similar to the results of ascorbic acid. Citric acid, a tricarboxylic acid, had no effect on HeLa cells.
By using amino acid mixtures, a comparative study of nutritional effects of dietary essential amino acid proportions (EA %) has been made between growing and adult rats. Included were adult rats which were repletiog from an 8-day protein depletion. It was shown that for growing rats at least 55 EA % was required to attain the maxi mum values of growth, nitrogen balance, nitrogen balance efficiency (nitrogen balance/nitrogen intake) and protein efficiency ratio (PER). The maximum biological value was found to be 94 at the 50 EA % level. For adult rats, at least 40 EA % was required to gain the maximum values of nitrogen balance and nitrogen balance efficiency under both main tenance and repletion. The biological values were found to be nearly 60 and 80 for maintenance and repletion, respectively.
Malnutrition is often associated with alcoholism. Nutri tional deficiencies found in alcoholic patients are mostly related to pro tein and B-vitamins. The purpose of this study was to determine whether pantothenic acid nutrition is altered in patients with prolonged intake of alcohol. Urinary pantothenic acid was measured in alcoholic patients during three intervals in a 10-week rehabilitation period. Pantothenic acid excretion of alcoholic patients revealed a lower excretion in an acute phase of the disease (2.7mg/day) than reported excretion of normal individuals (3.9mg/day). Inadequate intake of nutrients may have been a contributing factor. In chronic alcoholic patients who participated in a 10-week rehabilitation program, excretion approximated intake at the beginning of the period (6.6 mg/day) and decreased to less than one half this amount (2.7mg/day) at the end of the rehabilitation. It may be speculated that alcoholic patients, in general, are unable to utilize pantothenic acid from the diet efficiently, but as they are rehabilitated, more of this vitamin is retained in the body for useful functions.
The responses of human subjects to a low pantothenic acid test diet and to the same diet supplemented with 10mg pantothenic acid daily for 63 days were observed. Pantothenic acid in urine and blood and also nitrogen balance were used as criteria for nutritional evaluation. The mean daily urinary pantothenic acid excretion decreased from 3.05 to 0.79mg in male adult subjects fed a pantothenic acid deficient diet and increased from 3.95 to 5.84mg in 4 subjects fed a 10mg supplement ed diet from the beginning to the end of 63-day study. Subsequently, a test dose of 100mg of pantothenic acid was given to both groups for a 7-day period. Subjects previously deprived of panto thenic acid retained 63% of the test dose on the first day of the test period in contrast to 48% retained by supplemented subjects. On the 7th day, both groups retained approximately 40% of the dose. While in general, blood pantothenic acid levels decreased in unsupple mented subjects and remained constant in supplemented subjects, blood pantothenic acid responded less readily to intake than urinary panto thenic acid. Nitrogen retention tended to be higher in supplemented subjects than in those deprived of dietary pantothenic acid.