When vitamin A was taken up to an amount of 13mg by ingesting as cod-liver oil, only a very small part was excreted in feces. The vitamin seems therefore to have been absorbed almost entirely from the intestinal wall. When from 19 to 302 mg of the vitamin were given as vitamin A palmitate dissolved in liver oil, the ratio of the amount absorbed to that ingested fell with increase in the amount administered. The maximum absorption seemed to be about 70 mg. The vitamin was proved to be relatively labile in feces so that the amount of the vitamin assumed to have been absorbed may include some vitamin oxidized in the intestines.

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The purpose of this study is to find out a reliable test for detecting the niacin metabolism in man by a parenteral test dose of niacin or nicotinamide. Systematic studies were made on the effect of varying doses and routes of administration upon the blood level of niacin and co-dehyrogenase, and upon the urinary excretion of niacin and N-methylnicotinamide. (1) The blood niacin and co-dehydrogenase levels were not changed by a subcutaneous test dose of nicotinamide ranging from 50 to 500mg. On the other hand, these levels were slightly increased by a test dose of 100 mg niacin in contrast to the equivalent amount of nicotinamide. The use of niacin is, however, not recommendable on account of its side effects. (2) The increase in urinary niacin continued during a 3-hour period following a test dose, while that in urinary N-methylnicotinamide lasetd for 24 hours. Thus, a subcutaneous test dose of 100 mg nicotinamide, together with the determination of the niacin and N-methylnicotinamide excretion in the urine specimen voided for 24 hours following the test dose was found to be a satisfactory method for the study on the niacin metabolism.

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Water soluble disulfonates of thiamine were prepared by exchange of anionic group of thiamine chloride hydrochloride with anion exchange resin, or by adding the aqueous solution of thiamine sulfate to the aqueous solution of barium sulfonate followed by the removal of barium sulfate resulted. Disulfonates of thiamine and oxythiamine, both less soluble in water, were prepared by adding the aqueous soltion of chloride hydrochloride of thiamine or oxythiamne to the aqueous solution of sulfonic acid or alkali sulfonate. Monosulfonates of thiamine, less soluble in water, were prepared by adding the aqueous solution of thiamine mononitrate to the aqueous solution of alkali sulfonate, or by treating the solution of the corresponding thiamine disulfonate with barium carbonate.

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Thiamine hydrochloride mixed to wheat flour was decomposed considerably during the summer or on standing in the thermostadt at 30℃. On the contrary, thiamine mononitrate, rhodanate and hydroiodide were stable under the same conditions.

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In young rats fed on a synthetic diet containing sucrose and pure crystals of every member of B-vitamins but thiamine, the typical syndrome of thiamine defficiency developed. The period of time required for the development of avitaminosis and the trend of change in body weight were almost the same as those found with the starch diet supplemented with some members of B-group, which authers used previously in many experiments. Even when some member or members of B-group were omitted from the sucrose diet mentioned above, the time for the development of thiamine avitaminosis and the change in body weight did not vary except when riboflavin was omitted.

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The method reported previously was improved so as to be capable of determining vitamin A with glyceroldichlorohydrine in a small amount (0.5ml) of plasma. The result of determination of vitamin A in the plasmas of adults, children and infants with this method were reported.

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The authors synthesized S-acetylthiaminediphosphate by acetylating thiaminediphosphate in order to obtain more definitive information regarding the role of thiaminediphosphate in the oxidative decarboxylation of pyruvate. The S-acetyl group in this compound under went transacetylation with cysteine as well as glutathione in aqueous media. The autors demonstrated that the hydrolysis of S-acetylthiaminediphosphate in the presence of chicken liver or pigeon breast muscle homogenate was promoted by the addition of glutathione.

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The growth activities of thiamine, its derivatives, pyrimidines and thiazoles on thiamine requiring mutant strains of E. coli are described. The pre-incubation of inoculum in glucose-phosphate solution has effects on the growth activities of thiamine and its moieties. Present experiments lead to the conclusion that many thiamine related compounds tested exert more characteristic influences on the growth of thiamine-less mutants than that of the wild-strain. The essential substituent of pyrimidine ring for activity is an NH_2 group at position 4 ; at 5 -CH_2OH, -CH_2NH_2 and -CHO permit the growth of pyrimidine-less mutant but -H, -CN and -COOH inhibit the growth. For the biological activities of the thiazole, the -CH_2CH_2OH at 5 seems to be essential ; -CH_2CH_2OCOCH_3 inhibits the growth of pyrimidine-less mutants. The -H at 2 is replaceable by = S or = H_2 but not by -NH_2 or -OH.

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Vitamin B_<12> concentration of healthy human whole blood could be determined utilizing Escherichia coli mutant # 215 as an assay organism. For the purpose of determining the vitamin of blood treated with papain, a modified synthetic medium of Grossowicz et al. brought the satisfactory results. Composition of the medium was based on the formula reported by Johansson, supplemented with 0.25 % of casamino acid treated with hydrogen peroxide to decompose methionine. Vitamin B_<12> concentration of 10 healthy human subjects were determined as described below. (1) In case of the samples pretreated by autoclaving with a KCN solution and an acetate buffer, vitamin B_<12> levels found were 0.269 ± 0.024 mγ/cc and their recovery rates were 87 to 105 %. (2) When the samples were assayed by means of paper bioautography after papain digestion, 0.276 ± 0.028 mγ/cc of vitamin B_<12> was found and the recovery rates were 88 to 110 %. Much higher amount of vitamin B_<12> was found in the serum than in the red cells.

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The amino acid nitrogen excreted in the 24 hour urine was found to be 172.6±18.5 mg and 91.8±21.1 mg for the average of 15 boys with nutritional dystrophy and for that of 15 boys without nutritional dystrophy respectively showing a significant diffence between them. The high urinary discharge of amino acid nitrogen was decreased markedly in the majority of the boys with nutritional dystrophy after an administration of riboflavin. The riboflavin deficiency seems therefore to be one of the factors governing the disturbances of the amino acid metabolism in children with nutritional dystrophy.

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As a preliminary sudy for the assay of folic acid and citrovorum factor in human urine by the use of Streptococcus faecalis and Leuconostoc citrovorum, the relationship of these bacteria to some salts in urine was examined. It was found that oxalate inhibits the growth of S.faecalis and Lc.citrovorum when added to the assay medium in excess of 5 mg per 10 ml of medium. The folic acid and citrovorum factor contents of urine were not increased by digestion with enzyme solutions prepared from hog kidney or chicken pancreas, indicating that there were no combined forms of folic acid and citrovorum factor excreted in urine. The urinary excretion levels of folic acid and citrovorum factor varied from 5.2 to 1.8 μg (3.7 μg on an averge), and from 1.4 to 0.5 μg (0.8 μg), respectively per bay in normal adults.

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(1) Three different thiazole-less mutants responded to cystine moderately, but one of which, mutant 26-43,responded, though barely measurably, to isoleucine, valine, serine, threonine, histidine and proline also. Mutants 70-17 and 70-23,the former responding to either pyrimidine or thiazole and the latter to intact thiamine only, were permitted to grow to a certain extent by cystine and isoleucine. On the other hand, mutant 283 which required either cystine or isoleucine did not respond to thiazole. (2) The combination of thymine and uracil was able to support the growth of a pyrimidine-less mutant 70-17. (3) It seems improbable that γ-aceto-γ-mercapto-propanol is involved in the normal thiazole synthesis of E.coli. (4) The activity of thiazole-less mutant 26-43 to couple thiamine pyrimidine and thiazole is comparable to that of it's parent E.coli ATCC 9637. The coupling activity of mutant 70-23 seems to be blocked absolutely and that of mutant 70-17 partially. The fact that mutant 70-17 responded to either pyrimidine or thiazole is explainable by the inability to synthesize enough thiamine from the pyrimidine and the thiazole, which have been synthesized by the organism. (5) Evidence was obtained to show that pyrimidine and thiazole moieties of thiamine are actually normal precursors of that growth factor in E.coli.

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This paper presents a method of purification with Amberlite IRC-50 of the sample solution containing 4-9 μg/ml of vitamin B_<12> as the final step of a series of processes for the preparation of vitamin B_<12> crystal. Almost all vitamin B_<12> contained in the sample solution which had been poured onto IRC-50 resin column was adsorbed forming a red band. The liquid chromatogram obtained by the elution with 0.1 N HCl-75% acetone showed that the majority of impurities adsorbed on the resin was eliminated in earlier fractions and that vitamin B_<12> solution of high purity could be obtained when appropriate fractions were collected. The vitamin B_<12> solution which had passed through Amberlite IR-4B resin column for the purpose of eliminating hydrochloric acid was evaporated under reduced pressure, followed by crystallization in aqueous acetone.

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The adsorption behaviors of about 20 kinds of commercial active carbon for vitamin B_<12> and impurities contained in the aqueous extract obtained from the activated sludge were investigated from the viewpoint of an industrial purification of the vitamin. According to the results obtained with "Strong-Shirasagi" from Takeda Pharmaceutical Co.Ltd., seemed to be most suitable for the purpose, in view of the adsorption capacity, the price of active carbon, the easiness of filtration and the elution behavior with 50% acetone.

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