Vitamin B₁₂ levels and its binding capacity in the synovial fluid of the patients with joint diseases have been investigated, and the presence of vitamin B₁₂ and its binding capacity in the synovial fluid have been demonstrated.
Synovial B₁₂ levels in the patients with rheumatoid arthritis were much lower than those in osteoarthritis, whereas B₁₂ binding capacity in the synovial fluid of rheumatoid arthritis was higher than that in osteoarthritis.
These results suggest that B₁₂ metabolism in the synovia is related to the clinical features seen in rheumatoid arthritis.

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Protein biosynthesis, using ¹⁴C-serine and related aspects in pyridoxine deficient rats were studied. The following results were obtained.
1. The activities of rat liver succinate dehydrogenase, xanthine oxidase and alanine aminotransferase decreased with the severity of pyridoxine deficiency.
2. A reduced incorporation of ¹⁴C-serine into protein, in vitro, was observed in the pH-5 enzyme microsomal preparations obtained from pyridoxine deficient rats as compared to the normal controls. This reduction is partially overcome by the subcutaneous injection of pyridoxine to pyridoxine deficient animals two hours prior to killing.
3. The pH-5 enzymes were affected to a considerable extent in pyridoxine deficiency.
4. The total RNA of the liver decreased while the sRNA was almost unaffected in pyridoxine deficient animals.
5. The transfer of aminoacyl-tRNA to microsomes was also affected in pyridoxine deficiency by affecting the soluble transfer enzyme fraction.
6. An appreciable decrease in the total liver GSH content was observed in pyridoxine deficient rats.

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Treatment of yeast alcohol dehydrogenase [EC 1.1.1.1] (YADH) with dehydroascorbic acid (DHA) or D-arabinosone resulted in inactivation of the enzyme. Effects of other dicarbonyl compounds, such as D-glucosone and triosone, on YADH were also examined, and they were found to be less effective than D-arabinosone or ineffective.
The inactivation by DHA or D-arabinosone was accompanied by decrease of free sulfhydryl (SH) groups of the protein, and it was completely prevented by addition of SH compound. Treatment of the inactivated enzyme with β-mercaptoethanol led to partial reactivation with concomitant restoration of SH groups.
The inactivation of YADH was accelerated by NAD⁺ as well as NADH specifically.
These results strongly supported a possibility that DHA and D-arabinosone afforded the inhibitory effect on YADH through oxidation or modification of SH groups of the protein, which was favored in the presence of the coenzyme.

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An unidentified flavin compound was found in the extract of cat liver. It was purified by a combination of adsorption, ion exchange, partition, and gel chromatographies. The compound was identified as riboflavinyl α-D-glucoside by spectroscopic and chromatographic studies, analvses of sugar, and digestion with glucosidases. The possibility of the natural occurrence of riboflavinyl glucoside is discussed.

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Employment of a shift reagent [Eu (DPM)₃] presents decisive information on structural problems of polyene ester and ether such as retrovitamin A and isoanhydrovitamin A. A novel n. m. r. approach for an unambiguous identification of phenolic acetates including cresyl and tocopheryl acetates is also discussed by using the reagent. The method facilitates simultaneous determination of tocopherols in a mixture together with a definite characterization and appears to have a wide applicability to the chemistry of phenolic compounds.

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The uptake of thiamine in Escherichia coli was inhibited by thiamine phosphates. It was also demonstrated that the binding of thiamine to thiamine-binding protein, which is thought as a functional component in the transport system of thiamine, is markedly inhibited by thiamine phosphates.
The possibility that thiamine and thiamine phosphates share a common transport system in Escherichia coli is discussed.

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1. Pantothenic acid (PaA), coenzyme A (CoA) and their intermediates in rat liver were fractionated by DEAE-cellulose column chromatography and identified by paper chromatography. It was noted that among PaA derivatives, CoA was present in the largest amount, followed by 4′-phosphopantetheine (P-PaSH) and free PaA was found only in a very small amount.
2. ¹⁴C-PaA was administered to PaA deficient rats and PaA, P-PaSH and CoA in the liver were fractionated with a DEAE-cellulose column chromatography and it was observed that ¹⁴C-PaA was incorporated into each of the three fractions.
3. Changes in incorporation of ¹⁴C-PaA into each fraction with time was observed. The incorporation of ¹⁴C-PaA into P-PaSH was earlier than into CoA. This suggests that the isolated P-PaSH is not a decomposed product from CoA but is a precursor for CoA synthesis.

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The absorption of chloroethylthiamine, a new coccidiostat, from chick intestine was studied by means of ligated loop technique. From the linearity of doseabsorption relationship, it was indicated that both chloroethylthiamine and thiamine were absorbed by a passive diffusion mechanism in a dose level between 0.5 and 15mg. In such a dose level, chloroethylthiamine was easily absorbed from various parts of the chick intestine and the rate was appreciably higher than that of thiamine. However, the rate of thiamine absorption was increased significantly when the dose level was lowered down to 1.0μg/ml, suggesting that thiamine is absorbed from chick intestine by an active transport in such a low dose level as 10^-6M. It was found that the absorption of 1μg or less thiamine was strongly inhibited by chloroethylthiamine and pyrithiamine, while not by oxythiamine. Therefore, provided that an active transport system is present in the nutritional system of the coccidium, it was assumed that chloroethylthiamine acts on the coccidium as a strong inhibitor against their thiamine uptake from the host cells.

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The route of arrival of chloroethylthiamine at the cecal site after oral administration to chick was examined, as the drug is particularly active against Eimeria tenella which is parasitic in the cecal tissue. Macroautoradiography of chick whole gastrointestinal tract and the assay of radioactivity of various parts of the tract periodically after oral administration of ³⁵S-chloroethylthiamine indicated that chloroethylthiamine arrives and accumulates at the cecal site mainly by the passage through the digestive tract, in the highest concentration at about 8 hr after administration. It was found that when administered into the ligated duodenal loop only a slight radioactivity was distributed in the cecal tissue. In addition, the most of radioactivity orally administered was found to be excreted into the urine during the first 5 hr with the maximum rate between 2 and 4 hr, indicating that the urinary backflow is not participating in the accumulation in the ceca.

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An active transport of thiamine from chick intestine was proved by means of the in vitro tissue accumulation method. The intracellular to extracellular concentration ratio in the intestinal tissue was found to exceed unity with respect to free thiamine, indicating a transport against a concentration gradient. All of the other requirements for the concept of an active transport, that is, the saturation kinetics, the temperature dependency, the energy requirement and the competitive inhibition by structural analogues were also found to be filled for the thiamine transport. It was found that chloroethylthiamine has no inhibitory effect on the thiaminokinase activity, while inhibits the thiamine uptake competitively. These results suggest that there is a carrier system for thiamine transport which is not dependent upon the phosphorylation process. A possibility that the property of chloroethylthiamine to inhibit the active transport of thiamine competitively plays an important role in exerting its anticoccidium activity was pointed out.

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