By xin526
背景：母亲服用大豆后异黄酮在婴儿的生物利用率仍是个未知数。目的：我们的目的是比较异黄酮的利用率在含异黄酮的母乳喂养（BF）（在母亲进食大豆饮料后）和直接大豆喂养（TF）的婴儿中不同。设计：18名哺乳母亲不要给婴儿喂养大豆食品，在2－4天内每日自己食用一份大豆蛋白饮料，并收集自己的尿液和乳汁和婴儿的尿液。儿科医生负责采集婴儿的静脉血浆。另外的一组儿童在喂食豆腐后，同样被收集血浆和尿液。血浆和尿液中异黄酮通过液体光谱测定法测定。结果：在7个对象中异黄酮值值得关注从母亲服用大豆饮品的基线值上升，在母亲的尿液中从18.4～13.0nmol/mg至135.1～26.0nmol/mg。肌酐在母乳中从5.1～2.2nmol/mg至70.7～19.2nmol/l，在婴儿尿中从29.8～11.6nmol/ma至111.6～18.9nmol/mg。异黄酮的血浆平均浓度在BF组婴儿为19.7～13.2nmol/l。而TF组婴儿的异黄酮平均值要高出很多（尿229～129nmol/mg；血浆肌酐，1049～403nmol/l）。统计学显示在不同的两组研究，在母亲与婴儿，在婴儿之间存在显著的关联性。一小时标准量的异黄酮的消耗量比BF组婴儿的尿异黄酮排泄剂量低81％，而比TF组的婴儿高24％。
结论：通过由尿液分析婴儿全身系统的异黄酮情况，在婴儿比成人更容易出现口服大豆后异黄酮的增多。
出处：Am J Clin Nutr. 2006 Aug;84(2):406-13.
Isoflavones in breastfed infants after mothers consume soy.
BACKGROUND: The bioavailability of isoflavones in children after soy exposure is uncertain. OBJECTIVE: We aimed to compare isoflavone patterns in infants exposed to isoflavone-containing breast milk (BF), in tofu-fed (TF) infants, and in mothers consuming a soy beverage. DESIGN: Eighteen nursing mothers who were not feeding soy foods to their infants consumed one daily serving of a soy protein beverage for 2-4 d and collected their own milk and urine and infant urine. Plasma was collected from infants if venous blood draws were ordered by pediatricians. Blood and urine were collected from additional children after they consumed tofu. Isoflavones were measured by liquid chromatography-mass spectrometry. RESULTS: In 7 subjects, isoflavone values increased significantly from baseline after mothers ate soy: in maternal urine (x +/- SEM) from 18.4 +/- 13.0 to 135.1 +/- 26.0 nmol/mg creatinine, in breast milk from 5.1 +/- 2.2 to 70.7 +/- 19.2 nmol/L, and in infant urine from 29.8 +/- 11.6 to 111.6 +/- 18.9 nmol/mg creatinine. The mean isoflavone concentration in plasma obtained from 11 BF infants was 19.7 +/- 13.2 nmol/L. TF infants had much higher mean isoflavone values (urine, 229 +/- 129 nmol/mg creatinine; plasma, 1049 +/- 403 nmol/L). Statistically significant correlations were observed between the types of fluids investigated within mothers, between mothers and infants, and within infants. Urinary isoflavone excretion per hour adjusted for dose per body weight was 81% lower for BF infants and 24% higher for TF infants than for their mothers after eating soy. CONCLUSIONS: More isoflavones appear in children than in adults after adjustment for isoflavone intake. Systemic isoflavone exposure in infants can be determined by urinary analysis.
PMID: 16895891
中国幼儿锌稳态的主要变化
By hummingbirds
背景：当前需要一个析因方法估计一个人锌的需要量，测量锌稳态的主要变化是一个先决条件。对于初学走路的小孩来说，这个方法需要的数据无法获得，他们对锌的需要量是从其它年龄组用外推法估计的。 目的：研究目的是测量中国农村和小城镇的初学走路的小孩锌稳态的主要变化。 设计：锌稳定同位素示踪剂于一天饮食中口服和静脉输入43个初学走路的小孩体内。然后在家中进行代谢物收集，包括膳食副本、定量的粪便收集、当场的尿液采样。用二元同位素示踪剂比率技术测量微量吸收锌（FAZ），同位素稀释技术测量内源性排泄锌（EFZ）。 结果：没有发现性别和组别差异。而且，结果综合43个初学走路的小孩，其年龄范围是19～25个月，主食为精白米。结果（均数±标准差）是每天总饮食的锌为（1.86±0.55）mg；每天内源性排泄锌为（0.35±0.12）mg；每天测量微量吸收锌为（0.67±0.23）mg；血浆锌浓度为（65.0±8.3）μg/dL。饮食中肌醇六磷酸盐与锌的摩尔比值为2.7：1。结论：与估计的平均饮食摄入锌和生理需要锌相比，在这个人群中平均摄入和吸收锌较低，血浆锌与锌缺乏相一致。初学走路的小孩肠内丢失内源性的锌超过预先的估计，有一些证据表明人们对于低锌摄入和吸收反应保守。
出处：Am J Clin Nutr. 2006 Aug;84(2):389-94.
Major variables of zinc homeostasis in Chinese toddlers.
BACKGROUND: Measurement of the major variables of zinc homeostasis is an essential prerequisite for estimating human zinc requirements, which currently require a factorial approach. The data required for this approach have not been available for toddlers, whose requirements have been estimated by extrapolation from other age groups. OBJECTIVE: The objective of the study was to measure key variables of zinc homeostasis in rural and small-town Chinese toddlers. DESIGN: Zinc stable-isotope tracers were administered intravenously and orally with all meals for 1 d to 43 toddlers. Subsequent metabolic collections in the homes included duplicate diets, quantitative fecal collections, and spot urine sampling. Fractional absorption of zinc (FAZ) was measured by a dual-isotope tracer ratio technique, and endogenous fecal zinc (EFZ) was measured by an isotope dilution technique. RESULTS: No group or sex differences were found. Therefore, results were combined for 43 toddlers aged 19-25 mo whose major food staple was white rice. Selected results (x+/- SD) were 1.86 +/- 0.55 mg total dietary Zn/d; 0.35 +/- 0.12 FAZ; 0.63 +/- 0.24 mg total absorbed Zn/d; 0.67 +/- 0.23 mg EFZ/d; and 65.0 +/- 8.3 microg plasma Zn/dL. The molar ratio of dietary phytate to zinc was 2.7:1. CONCLUSIONS: The mean intake and absorption of zinc in this population are low in comparison with estimated average dietary and physiologic requirements for zinc, and plasma zinc values are consistent with zinc deficiency. Intestinal losses of endogenous zinc exceed previous estimates for toddlers, and only modest evidence exists of conservation in response to low zinc intake and absorption.
PMID: 16895888
淋巴细胞丙酰辅酶A羧化酶及其生物素活化是人类边缘生物素活化的敏感指标
By qbx826
背景：边缘生物素缺乏对人类有致畸作用，不依赖于肾功能的生物素状况指示剂有可能成作为怀孕期间生物素状况的指标。以往的一个生物素缺乏实验研究提示外周血淋巴细胞（PBL）丙酰辅酶A羧化酶（PCC）活性是生物素的一个敏感指标。目的：我们评价丙酰辅酶A羧化酶的活性测量和边缘生物素缺乏时生物素活化丙酰辅酶A羧化酶活性测定的效用。设计：通过28天蛋白的食用来诱导7名（3名女性）生物素缺乏者，并在0、14和28天（排除期）以及44和65天（饱和期）收集血样和尿样。外周血淋巴细胞分别在含有生物素（活化）和不含有生物素（对照）培养后测定丙酰辅酶A羧化酶活性。丙酰辅酶A羧化酶活性系数是PBL活化后PCC活性与PBL对照PCC活性之比。通过Fisher多重比较和Bonferroni校正对所有变量差异进行重复测量的方差分析。结果：尿中生物素的排泄变化确认边缘生物素缺乏构建成功。至14天时，所有研究对象的PCC活性显著均低于正常值下限（P < 0.0001），至28天，PCC活性系数显著增高（P = 0.003），7人中有6人高于正常范围上限。结论：PCC活性是目前为止生物素状态最敏感的指标，在将来怀孕的研究中，淋巴细胞PCC活性是评估生物素状态有用的指标。
出处：Am J Clin Nutr. 2006 Aug;84(2):384-8.
Lymphocyte propionyl-CoA carboxylase and its activation by biotin are sensitive indicators of marginal biotin deficiency in humans.
BACKGROUND: Marginal biotin deficiency may be a human teratogen. A biotin status indicator that is not dependent on renal function may be useful in studies of biotin status during pregnancy. A previous study of experimental biotin deficiency suggested that propionyl-coenzyme A carboxylase (PCC) activity in peripheral blood lymphocytes (PBLs) is a sensitive indicator of biotin status. OBJECTIVE: We examined the utility of measuring PCC activity and the activation of PCC by biotin in detecting marginal biotin deficiency. DESIGN: Marginal biotin deficiency was induced in 7 adults (3 women) by egg-white feeding for 28 d. Blood and urine were obtained on days 0, 14, and 28 (depletion phase) and 44 and 65 (repletion phase). PBLs were incubated with (activated) or without (control) biotin before PCC assay. The activation coefficient of PCC is the ratio of PCC activity in activated PBLs to that in control PBLs. The significance of differences for all measurements was tested by repeated-measures analysis of variance with Fisher's post hoc test and Bonferroni correction. RESULTS: Changes in the urinary excretion of biotin and of 3-hydroxyisovaleric acid confirmed that marginal biotin deficiency was successfully induced. By day 14, PCC activity had decreased (P < 0.0001) to below the lower limit of normal in all subjects. By day 28, the activation coefficient of PCC had increased significantly (P = 0.003) and was above the upper limit of normal in 6 of 7 subjects. CONCLUSION: PCC activity is the most sensitive indicator of biotin status tested to date. In future pregnancy studies, the use of lymphocyte PCC activity data should prove valuable in the assessment of biotin status.
PMID: 16895887
