著者
近藤 厚生 岡井 いくよ 早川 ちさ 下須賀 洋一
出版者
公益社団法人 日本ビタミン学会
雑誌
ビタミン (ISSN:0006386X)
巻号頁・発行日
vol.83, no.5-6, pp.250-255, 2009-06-25 (Released:2017-10-10)
参考文献数
16

We have been assessing awareness of a role of folic acid, intake of folate supplements and dietary folate consumption among pregnant women during the past 6 years. A total of 6902 pregnant women responded to our questionnaires distributed from 2002 to 2007. Dietary folate was measured by analyzing food records completed by 441 pregnant women from 2003 to 2007. Rates of awareness and rates of folate supplementation were considerably low, 15% and 9%, respectively, in 2002, but increased year after year to 39% and 43%, respectively, in 2007. Of the 441 pregnant women who reported their food records 150 (34%) simultaneously took folate supplements. Although the amount of dietary folate consumed averaged 336μg/day in all the women, 126 women in the 1^<st> trimester consumed only 283μg/day, 120μg less than what was recommended by the Government. It was further observed that 61% of the women in the 1^<st> trimester neither consumed 400μg of dietary folate nor took folate supplements suggesting that the majority of the women were facing a real risk of conceiving fetuses afflicted with neural tube defects. Following strategies seem necessary to suppress incidence of neural tube defects in Japan: First, importance of folate supplementation should be stressed in a booklet for pregnant women. Second, the Government should repeatedly send folate information in relation to developing fetuses to the general public. Third, folate information should be given to young girls at curriculums of the junior and senior high school. Fourth, folate supplements should be given free for those women who wish to conceive. Finally, implementation of food fortification with folic acid should be seriously considered by the Government.
著者
浅山 亮二 浜田 幸子
出版者
公益社団法人 日本ビタミン学会
雑誌
ビタミン (ISSN:0006386X)
巻号頁・発行日
vol.36, no.3, pp.237-240, 1967-09-25 (Released:2018-02-10)

The intra-ocular pressure of the rabbits was maintained for one hour at 150,140,130,110,90,70,and 56mmHg with a leveling manometer and the concentration of total thiamine, free thiamine and thiamine phosphate in the retina and the optic nerve was measured. The concentration of total thiamine and its phosphate in the retina decreased with the elevation of the intra-ocular pressure over 90mmHg. When the intra-ocular pressure persisted at 150mmHg for 2.5 hours, contents of thiamine phosphate in the retina decreased further than when the elevation persisted for one hour. When the duration of the elevation of the intra-ocular pressure at 150mmHg was limited to one hour, the decrease of the total thiamine and its phosphate in the retina proved to be reversible by the normalizing of the intra-ocular pressure. But when the elevation of the intra-ocular pressure at 150mmHg persisted for 2.5 hours, decreased contents of the total thiamine and its phosphate were not reversed even when the intra-ocular pressure returned to normal. The intra-ocular pressure was maintained at 30,56,and 150mmHg with a manometer. One hour after an intravenous injection of thiamine propyldisulfide 10mg per kg, the concentration of total thiamine, free thiamine and thiamine phosphate in the ocular tissues was measured. The concentration of all types of thiamine in the retina and the choroid almost decreased when the intra-ocular pressure became higher than 56mmHg, as compared with the concentration in these tissues of normal intra-ocular pressure one hour after an intravenous injection of thiamine propyldisulfide 10mg per kg, and these decreases became greater with the elevation of the intra-ocular pressure.
著者
赤井 翔太 生城 浩子 澤井 大樹 林 秀行 神谷 信夫 宮原 郁子
出版者
公益社団法人 日本ビタミン学会
雑誌
ビタミン (ISSN:0006386X)
巻号頁・発行日
vol.88, no.7, pp.358-365, 2014

Homoserine dehydrogenase catalyzes the conversion of L-aspartate-4-semialdehyde to L-homoserine. Homoserine dehydrogenase is required for the biosynthesis of the three essential amino acids, i.e. lysine, methionine, and isoleucine, from aspartic acid. This enzyme attracts attention also as a promising antifungal drug target. We have determined the crystal structures of homoserine dehydrogenase from Thermus thermophilus HB8 in both substrate-free form and homoserine-binding form by X-ray diffraction. Crystallization conditions were surveyed at 293 K by using a hanging-drop vapor-diffusion method. The substrate-free form was solved to 1.4 Å resolution and the homoserine-binding form was solved to 2.0 Å resolution. The homoserine dehydrogenase was a dimer with each subunit composed of three distinct domains, nucleotide-binding, dimerization, and substrate-binding domain. In the homoserine-binding forms, the amino group of homoserine made a hydrogen bond to the side chain carboxylate of Glu180. This hydrogen bond induced the conformation change of Thr165-Pro183 loop, which made the loop close to the active site. The substrate homoserine was rigidly recognized by several amino acid residues in the enzyme active site, indicating that Lys99 or Lys195 would be an essential catalytic residue to facilitate hydride transfer.
著者
柴田 克已
出版者
公益社団法人 日本ビタミン学会
雑誌
ビタミン (ISSN:0006386X)
巻号頁・発行日
vol.71, no.11, pp.519-529, 1997-11-25 (Released:2018-04-07)
参考文献数
17
被引用文献数
1

Niacin is biosynthesized from tryptophan and its ability is enough to sustain the demand of niacin animal or human body. Therefore, niacin itself does not need to take. Vitamin B groups and minerals are required in the conversion of niacin from tryptophan. Thus, we investigated the effects of feeding with a thiamin-free, riboflavin-free, pyridoxine-free, or mineral-deficient diet on the conversion ratio of tryptophan to niacin in rats. In the thiamin-free experiment, the ratio was higher in the thiamin-free group than in the control. In riboflavin-deficient rats, the conversion ratio was not affected. In the pyridoxine-free experiment, the ratio was lower in the pyridoxine-free group than in the control. In the mineral-deficient experiment, the sum of the urinary excretion of nicotinamide and its metabolites was lower in a deficient group than in the control. Accordingly, deficiencies of pyridoxine and/or minerals directly caused niacin deficiency, but thiamin- and riboflavin-deficiencies did not.
著者
辻村 卓 小松原 晴美 荒井 京子 福田 知子
出版者
日本ビタミン学会
雑誌
ビタミン (ISSN:0006386X)
巻号頁・発行日
vol.71, no.2, pp.67-74, 1997-02-25
被引用文献数
7

本実験の結果、ミネラルは各試料について、特徴的な年間の含有量変動をつかむことはできなかった。分析項目中、含有量の変動が比較的大であったカロチンとV.Cについて含有量変化の通年の変動が大きい試料、小さい試料に分けて示す。(1)栄養成分量が季節で変動する試料 カロチンとV.Cの充実期が重なるもの:キャベツは通年が出回り期であるが、12〜4月を両ビタミンの充実期としている。ミネラルは特に傾向を示していない。トマトは夏期にビタミンが充実していた。しかし、四訂食品成分表作成時とは異なる品種が店頭に出回っている。カロチン、V.Cとも成分表値を下回った。ほうれんそうは11〜3月の出回り期がビタミンの充実期であった。ミネラルでは季節による含有量の変化は認められなかった。カロチンとV.Cの充実期が異なるもの:かぼちゃはカロチンの含有量が2〜6月に充実していた。V.Cは3, 6, 12月に40mg以上となったが、7, 8月は低値であった。さやいんげんはV.Cが5, 6月に最高含有量であった。キウイフルーツはV.Cが1〜5月にやや低値であったが、年間を通じて高含有量(最低36mg)を維持した。カロチン含有量は低値であった。カロチンのみ変動:にんじんは通年が出回り期(10月が少し多い)であるが、カロチンは5〜10月に充実していた。ビタミンCのみ変動:ジャガイモはV.Cが5〜9月に充実していた。ミネラルでは季節による含有量の変化が認められなかった。(2)栄養成分量が季節で変動しない試料 セロリーの通年の測定平均値はカロチン77μg, V.C6mg/100gであるが、毎月の測定値もこれらに近いものであった。ピーマンの出回り期は5, 6月であるが、栄養成分、特にV.Cは通年にわたり高含有量(最低70mg)を維持した。
著者
井上 裕康
出版者
公益社団法人 日本ビタミン学会
雑誌
ビタミン (ISSN:0006386X)
巻号頁・発行日
vol.78, no.12, pp.621-623, 2004-12-25 (Released:2017-10-10)
参考文献数
13

レスベラトロールは赤ワインに含まれる抗酸化作用を持つフィトアレキシン(抗菌性物質)である. レスベラトロールは中等度のワイン消費が心血管病, 脳卒中, 痴呆の危険度と負の相関を示す, いわゆる「フレンチパラドックス」に関与する物質と考えられてきた. 我々は最近, レスベラトロールが核内受容体PPAR(peroxisome proliferators activated receptor)αとPPARγを選択的に活性化すること, さらにPPARα活性化が脳保護効果をもたらすことを見いだした. これらの知見は「フレンチパラドックス」を説明する新しい作用機構を提供すると考えている. 一方で, レスベラトロールは寿命延長効果を持つカロリー制限模倣物質であること, オレイルエタノールアミドがPPARαの新しい内因性リガンドであり, その活性化によって食欲をコントロールすることが報告されている. そこでこれらの知見を含めて, 今後の展望とともに紹介したい.
著者
妹尾 春樹 畑 隆一郎
出版者
公益社団法人 日本ビタミン学会
雑誌
ビタミン (ISSN:0006386X)
巻号頁・発行日
vol.68, no.9, pp.501-513, 1994-09-25 (Released:2018-03-30)

Stellate cells (vitamin A-storing cells, lipocytes, fat-storing cells, Ito cells) exist in the perisinusoidal space of the hepatic lobule, and store 80% of retinoids in the whole body as retinyl palmitate in lipid droplets in the cytoplasm. Under physiological conditions, these cells play key roles in the control of retinoid homeostasis ; they express specific receptors for retinol-binding protein (RBP), a binding protein specific for retinol, on their cell surface, and take up the complex of retinol and RBP by receptor-mediated endocytosis. Whereas, under pathological conditions such as liver cirrhosis, these cells lose retinoids, and synthesize a large amount of extracellular matrix (ECM) components including collagen, proteoglycan and adhesive glycoproteins. Morphology of these cells also changes from the star-shaped stellate cells to that of fibroblasts or myofibroblasts. ECM components regulate the morphology, proliferation, and functions of the stellate cells. L-ascorbic acid 2-phosphate, a long-acting vitamin C derivative, further modulates this cellular regulation by ECM components.
著者
上西 薫
出版者
日本ビタミン学会
雑誌
ビタミン (ISSN:0006386X)
巻号頁・発行日
vol.2, no.1, pp.21-23, 1949