Administration of a large excess myoinositol to young rats fed on Forker's basal diet provoked significant delay in growth and the rise of P/N ratio of hepatic lipid fraction. However, these effects were diminished by elevating the content of protein in the ration, or by increasing the amount of choline administration. The fact should be an additional evidence for the concept of antagonism between choline and myoinositol, and for that of the intervention of myoinositol into the phospholipid metabolism.
From the present result together with the previous one that proved a beneficial effect of myoinositol on the growth of rats, it was concluded that the exogenous myoinositol could be precursor of inositol phosphatide and promotes the cell growth so far as its amount is not increased enough to disturb the phospholipid metabolism e. g. choline phosphatide biosynthesis.

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1. Influences of light-irradiation on the enzymic conversion of propanediol to propionaldehyde catalyzed by 5, 6-dimethylbenzimidazolyl cobamide coenzyme-dependent dioldehydrase were examined under the following conditions: (a) holoenzyme was irradiated, prior to the incubation with the substrate in the dark, under aerobic and anaerobic conditions, respectively; (b) light was irradiated on the mixture of apoenzyme and the coenzyme at 0° where the holoenzyme was hardly formed, then incubated with the substrate in the dark; (c) illumination was carried out after the enzymic reaction began to proceed steadily.
2. The irradiation on the holoenzyme under anaerobic conditions stimulated the reaction rate twice that without illumination. On the other hand, the enzyme activity decreased to less than a half under aerobic condition. The accelerating effect of the illumination under anaerobic conditions is considered to be due to the anaerobic cleavage of the cobalt-carbon bond in the enzyme linking a 5′-deoxyadenosyl moiety, which forms a protein-bound B_12r. and a 5′-deoxyadenosyl radical, even if the protein-bound B_12r may be further reduced to the state of B_12s before the reaction with the substrate. The ineffectiveness of the aerobic illumination indicates that hydroxocobalamin and adenosine-5′-aldehyde or adenosine-5′-carboxylic acid bound to the apoprotein cannot react with the substrate. Under the condition b, in which the coenzyme was in part transformed to hydroxocobalamin by irradiation, the coenzyme activity decreased to the same extent as that of the aerobic photolysis of the holoenzyme mentioned above. When the enzymic reaction began to proceed steadily (condition c), light did not affect the reaction rate.
3. Associated with the appearance of a B_12r-like spectrum in the course of the enzymic reaction, the enhancement of the holoenzyme by anaerobic photolysis would be attributed to the stimulation of the cleavage of the cobalt-carbon bond followed by the formation of a protein-bound B_12r and 5′-deoxyadenosyl radical, at least as an intermediary step.
4. The ineffectiveness of irradiation on the incubation mixture of the apoenzyme with methylcobalamin, which is known to be a competitive inhibitor in the enzyme system, suggests that the enzymic reaction cannot be mediated by a protein-bound B_12r or B_12s alone but that protein-bound 5′-deoxyadenosyl part is also necessary for the reaction. The possible participation of 5′-deoxyadenosyl moiety was supported by the competitive inhibition caused by the addition of adenosine.

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1. The method of Zima for synthesizing thiamine monophosphate disulfide (TMPDS) was studied and improved in several points.
2. The products obtained by the authors were somewhat different in physical and chemical properties.
3. TMPDS was shown to give polymorplism, i.e., α-, β- and γ-forms. They have different color, water of crystallization, decomposition points and infra-red absorption spectra.

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1. The ultraviolet absorption spectrum of thiamine monophosphate disulfide (TMPDS) changed with pH like thiamine, the isosbestic points being at 239 and 277mμ.
2. pKa₁, pKa₂, and pKb were obtained from the titration curve. The pKa value obtained from the change in ultraviolet absorption spectrum with pH was almost the same as that obtained from titration, and the isoelectric point was 3.96. This value well corresponded to the properties of solubility and stability.
3. It was hardly soluble in organic solvents. The solubility in water at 30° was 4.94% (w/v) at pH 7.0 and 4.50% (w/v) at pH 3.86.
4. It could be separated from the related compounds by thin layer chromatography using pyridine-acetic acid-water as a solvent system.
5. The anhydrate of TMPDS was hygroscopic, forming a stable powder-like material with 4-8 molecules of water in 24 hours.
6. The stability of TMPDS solution (1-10mg/ml) after heating at various pH levels for 1-2 hours was greatest at pH 4 below 70°, but it was hydrolyzed at above 80°. It was unstable to light.
7. The ultraviolet absorption spectrum and fluorescence spectrum of the thiochrome phosphate obtained by cysteine reduction and BrCN oxidation at pH 13.0 were the same as those of thiochrome obtained from thiamine. The recovery was more than 98%.
8. The total thiamine value can be determined by measuring the ultraviolet absorbance and fluorometry in alkaline solution obtained by BrCN oxidation after cysteine reduction. Thiamine disulfide and free thiamine can be determined by fluorometry of the isobutanol extract of this solution. Thiamine monophosphate and free thiamine can be determined by ultraviolet absorbance and the fluorometry of the alkaline solution obtained by BrCN oxidation of the solution without cysteine reduction. Free thiamine can be determined by fluorometry of the isobutanol extract of this solution. TMPDS can be determined from each value thus obtained.
9. TMPDS in the blood can be determined with 95% recovery by combined use of cysteine reduction and Takadiastase hydrolysis.

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Thiamine monophosphate disulfide (TMPDS) exhibited the thiamine action in rats nearly equal to that of thiamine-HCl. After intravenous injection of TMPDS in a dog, the levels of total thiamine and thiamine diphosphate in blood were much higher than after administration of thiamine-HCl, retaining the level for a longer period.
On the other hand, TMPDS trended to retard the urinary excretion and it showed beneficial effects on analgesic action and prevention of fatigue in swimming of mice.
As for the general pharmacological action of TMPDS, it showed qualitatively similar behaviors against respiro-circulatory systems to those of thiamine-HCl. The former lowered the blood pressure more slowly than the latter in rabbits. Administration of TMPDS, 20mg per kg, brought about the tension and acceleration of the movement of the intestine in rabbits in situ similarly to thiamine-HCl. In any case, if the pharmacological action of TMPDS is assumed to be a side effect to vitamin action, it is considered to have only a veryr slightly one.
Acute toxicity in mice was much slighter than that of thiamine-HCl in mice. The compound was found much more resistant to thiaminase I and II than thiamine-HCl.

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Safety examinations of thiamine monophosphate disulfide (TMPDS) was performed by chronic toxicity and teratological tests and obtained the following findings.
1. In the chronic toxicity test, TMPDS was administered to rats intraperitoneally in doses of 100 and 50mg/kg daily for six months. No significant differences among the groups were observed in the body weight gain, food intake, organ weights and hematological and histological findings.
2. In the teratological test, 500, 100 and 50mg/kg of TMPDS were administered intraperitoneally to gestated rats and mice every day from the 7th to 14th day of gestation. No effects of TMPDS was observed on both fetuses and new-horns from the mother animals.

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Large amounts of ascorbic acid are recently used in curing pigment anomalies. Investigation was therefore carried out in animals and man on the fate of the vitamin administered in large amounts, especially on the excretion of oxalic acid and the following findings were obtained.
1. After administration of the large amounts of ascorbic acid, it was eliminated in urine mostly in the form of dehydroascorbic acid in the majority of cases (about 80%).
2. When ascorbic acid was administered orally or intramuscularly in a dose of 3g per day, there was no marked increase in the urinary oxalic acid. Oral administration of 9g of the vitamin resulted in an marked increase of the urinary oxalic acid (from 20 to 30mg).
3. With a rise in the dose of ascorbic acid, urinary diketogulonic acid was increassed. It seems to indicate that the large dose of ascorbic acid promotes the degradation of dehydroascorbic acid into digekogulonic acid, but further oxidation to oxalic acid does not occur markedly.
4. The amounts of oxalic acid-C¹⁴ detected in the urine of animals and man following the administration of AsA-C¹⁴ accounted for 1.0 to 1.5% and 0.16% of the C¹⁴ given in animals and man respectively.
5. Investigation on the effect of an intravenous an injection of a daily dose of 0.5mg of ascorbic acid carried out for 17 consecutive days on the formation of calculi with a lead ball inserted in the urinary bladder as a nucleus showed that the calculi formed around the nuclei in experimental animals was 7 times as heavy as those formed in the control animals. The amount of oxalic acid contained in the calculi was 0.73mg as contrasted to 0.33mg in the calculi of the control animals.

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The possibility of the formation of protein-thiamine mixed disulfide by the reaction of thiol type thiamine and the SS-groups of natural protein was studied using bovine serum albumin and the following results were obtained.
1. Under aerobic condition, much protein-bound thiamine was produced increasing with the rise of reaction time and pH.
2. Bound thiamine was also formed when γ-globulin, which contains as much SS-groups as bovine serum albumin, was used, but it was not the case with the bovine serum albumin, whose SS-groups had been partially reduced.
3. Under anaerobic condition, however, only a small amount of bound thiamine was produced. When the reaction mixture was subjected to Sephadex column chromatography, a small part of the SS-group of the protein was found to have been reduced.
4. From these results it is assumed that the production of much bound thiamine under aerobic condition is due to the thiamine disulfide produced by the action of dissolved oxygen and that the thiol-type thiamine per se can react only partially with the SS-group of bovine serum albumin.

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1. Lipoic acid and lipoamide in mixture can be separated and determined directly without any preliminary treatment under a certain condition of gas liquid chromatography.
2. As the internal standard, di-n-octylphthalate is suitable for lipoic acid and benzyl-n-butyl phthalate for lipoamide.
3. When lipoic acid was extracted with chloroform from the solution, and lipoamide from starch powder and both were determined promptly by gas liquid chromatography, the following average recoveries and standard deviations were obtained. Lipoic acid, 98.9±2.9%, and lipoamide, 98.8±2.7%.

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In order to determine if essential fatty acid (EFA) is necesary for rainbow trout as it is for mammals, the fish raised on a fat-free diet long enough to manifest deficiency symptoms were given ethyl esters of linoleic, linolenic and highly unsaturated fatty acids and the following effects were observed.
1. The posterior part of fish fed only the fat-free diet for 3 months was discolored and hardened. The posterior fin was worn out. In the extreme cases, the fin had almost disappeared, leaving the terminals of spiral column. Many of the fish died in this group. These symptoms might be caused by EFA deficiency. The fat-free diet was inferior to the diets containing fatty acid esters for weight gain and for efficiency of the diet.
2. Among the three fatty acid esters, highly unsaturated fatty acid esters were the best in the accumulation and efficiency of the diet, showing minimum mortality. Ethyl linoleate was the next and ethyl linolenate was the last of the three. Of each ester a 200μg dose was better than 50μg.
3. In this experiment, fish fed the diets containing more than 50μg esters per g of body weight per day, failed to cause deficiency symptoms, though a further experiment may be necessary to determine the minimum requirement of these fatty esters.
4. A recovery test was carried out with rainbow trout which had been fed the fat-free diet for two months. In the fat-free diet group, the symptoms of the deficiency could still be observed, but in the groups containing the 3 kinds of esters at the rate of 500μg per g of body weight per day, such symptoms were not observed.

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1. The effects of ribonucleosides or deoxyribonucleosides on the growth rate of Lactobacillus leichmannii were investigated using the ordinary microbioassay technique. It was found that the addition of both vitamin B₁₂ and ribonucleosides resulted in higher growth rate than a single addition of vitamin B₁₂. The finding was quite similar to the case where the addition of both vitamin B₁₂ and thymidine was more active than a single addition of vitamin B₁₂. Further, formation of deoxyribonucleoside was observed after addition of both vitamin B₁₂ and ribonucleosides.
2. Effects of the age of the cells on the deoxyribonucleoside formation were studied, and the best condition for producing the compounds by washed cell suspension of L. leichmannii was studied.
3. 2′-Deoxyribonucleosides were separated from the reaction products and studied chemically and microbiologically. By paper chromatography and bioautography they were separated and identified.
4. Formation of 2′-deoxyribonucleosides from the corresponding ribonucleosides with the washed cell suspension of L. leichmannii at the logarithmic phase of the growth rate was studied.

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