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Volume 85, Issue 9
Displaying 1-8 of 8 articles from this issue
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[in Japanese]Article type: Article
2011 Volume 85 Issue 9 Pages 459-462
Published: September 25, 2011
Released on J-STAGE: October 10, 2017
JOURNAL FREE ACCESSDownload PDF (497K) -
Hiroshi TamaiArticle type: Article
2011 Volume 85 Issue 9 Pages 463-470
Published: September 25, 2011
Released on J-STAGE: October 10, 2017
JOURNAL FREE ACCESSVitamin E status in the body is regulated through absorptive and metabolic systems. In the liver, α-tocopherol transfer protein (αTTP) preferably binds transported α-tocopherol and transfers it to vessels. In contrast, a large part of γ-tocopherol transported into the liver is metabolized. This discrimination of vitamin E by αTTP in the liver develops in the infant period and maintains α-tocopherol/γ-tocopherol ratio in the serum at a constant level thereafter. The expression of αTTP in the liver is also changed in diabetic animals and nutritional vitamin E status, such as deficiency and sufficiency. Another major mechanism to regulate vitamin E status in the serum is the metabolism of excessive α-tocopherol to α-CEHC (2,5,7,8-tetramethyl-2-(2'-carboxyethyl)-6-hydrochroman) in the liver and the resulting α-CEHC is secreted into the urine. A large part of γ-tocopherol administered to humans at a large dose is also metabolized to γ-CEHC in the liver and the resulting γ-CEHC stimulates the secretion of sodium to the urine in the kidney. This metabolism of α-tocopherol and γ-tocopherol to α-CEHC and γ-CEHC, respectively, also contributes to the maintenance of vitamin E status in the serum.View full abstractDownload PDF (952K) -
Toru FukuiArticle type: Article
2011 Volume 85 Issue 9 Pages 471-478
Published: September 25, 2011
Released on J-STAGE: October 10, 2017
JOURNAL FREE ACCESSThis review describes the characteristics of main assays for biotin and problems for standardization. The typical assays for biotin are microbiological assay, binding assay, and HPLC method. Microbiological assay is the initial method of the discovery of biotin. Since then, it has been popularly performed. Lactobacillus plantarum ATCC 8014 is generally used for microbiological assay. It has high sensitivity to biotin, but this strain is affected by biotin catabolites. Binding assay using avidin or streptavidin has been specific against biotin. This method is as simple as immunoassays. Recently, binding assay has obtained high sensitivity by using biochemical luminescence detection. However, this assay cannot separate biotin and biotin analogues. HPLC method is suitable for a standard method, because it is possible to determine biotin and its metabolites. Though various detection methods are combined to HPLC, they have not yet obtained sufficient sensitivity. Therefore, this paper describes the problems of the sample preparation before assay, sensitivity and reference materials for the establishment of a standard method.View full abstractDownload PDF (905K) -
Tsutomu FukuwatariArticle type: Article
2011 Volume 85 Issue 9 Pages 479-484
Published: September 25, 2011
Released on J-STAGE: October 10, 2017
JOURNAL FREE ACCESSDetermination of blood and urinary pantothenic acid levels are important to assess pantothenic acid status. The microbiological assay using Lactobacillus plantarum remains to be the most practical method for measurement of pantothenic acid levels in the blood, urine and food. Although several methods are available including radioimmunoassay, ELISA, HPLC, GC/MS, LC/MS and optical biosensor-based immunoassay, these methods are restricted to use. Major reason is that little interest has existed for assessing pantothenic acid deficiency. The radioimmunoassay and ELISA lack sensitivity, and need noncommercially available antisera. GC/MS requires a derivatization step to be volatile enough for GC. Although the HPLC-fluorimetric method and LC/MS show high sensitivity and selectivity to determine low level of pantothenic acid in the blood, these methods require further development. More biological data for pantothenic acid status will be required for setting pantothenic acid requirement.View full abstractDownload PDF (717K) -
Akiko Ohashi, Yuko Sugawara, Kaori Mamada, Naohiko Anzai, Shin Aizawa, ...Article type: Article
2011 Volume 85 Issue 9 Pages 485-491
Published: September 25, 2011
Released on J-STAGE: October 10, 2017
JOURNAL FREE ACCESSSupplementation of tetrahydrobiopterin (BH_4), an essential cofactor in nitric oxide and monoamine production, is used in treating a systemic deficiency of BH_4 despite of high cost medication due to short retention of supplied BH_4. Although it also potentially targets a local deficiency such as in some cases of cardiovascular dysfunction, understanding of transport mechanisms underlying the rapid BH_4-excretion is required to improve the therapeutic efficiency. Application of a membrane-protein expression system using Xenopus oocytes followed by a radioisotope assay has widely been employed in transporter research. The assay, however, is made difficult by the labile character of BH_4 while undergoing aerobic oxidation and enzymic conversion. We report here an application of a Xenopus-oocyte expression system to hENT1 and hENT2 for characterization of putative BH_4 transporter. The method allows for the efficient extraction of reduced pterins from a small number of oocytes followed by HPLC and highly sensitive fluorescence detection.View full abstractDownload PDF (893K) -
Saiko Ikeda, Saki NomuraArticle type: Article
2011 Volume 85 Issue 9 Pages 492-495
Published: September 25, 2011
Released on J-STAGE: October 10, 2017
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Shingo Aizawa, Akihito IshigamiArticle type: Article
2011 Volume 85 Issue 9 Pages 496-498
Published: September 25, 2011
Released on J-STAGE: October 10, 2017
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Kazuhiro YAMADAArticle type: Article
2011 Volume 85 Issue 9 Pages 499-500
Published: September 25, 2011
Released on J-STAGE: October 10, 2017
JOURNAL FREE ACCESSDownload PDF (318K)
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