The Journal of nutrition
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The Journal of nutrition · Mar 2004
Dietary L-arginine supplementation enhances endothelial nitric oxide synthesis in streptozotocin-induced diabetic rats.
This study tested the hypothesis that dietary arginine supplementation increases endothelial tetrahydrobiopterin (BH(4)) availability for nitric oxide (NO) synthesis in diabetic rats. Streptozotocin-induced diabetic rats either were given unrestricted access to a casein-based diet (Expt. 1) or were pair-fed the diet on the basis of the food intake per kg of body weight of nondiabetic rats (Expt. 2). Beginning 1 d after vehicle or streptozotocin injection, arginine-HCl (1.51%) or alanine (isonitrogenous control, 2.55%) was added daily to the drinking water for nondiabetic rats, whereas concentrations were adjusted (0.43% arginine-HCl and 0.73% alanine) in the drinking water for diabetic rats (which consumed more water) to ensure isonitrogenous provision. ⋯ Dietary arginine supplementation or provision of a BH(4) precursor normalized endothelial NO synthesis in diabetic rats. Arginine supplementation did not affect plasma glucose levels in nondiabetic rats, but reduced body weight loss and plasma glucose levels in diabetic rats. Thus, dietary L-arginine supplementation stimulates endothelial NO synthesis by increasing BH(4) provision, which is beneficial for vascular function and glucose homeostasis in diabetic subjects.
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The Journal of nutrition · Oct 2003
Replacement-fed infants born to HIV-infected mothers in India have a high early postpartum rate of hospitalization.
Access to safe breast-feeding alternatives for HIV-infected mothers and their infants in many settings is limited. We compared the rates of early postpartum hospitalization of infants born to HIV-infected mothers using different infant-feeding practices in a large government hospital in Pune, India. From March 1, 2000 to November 30, 2001, infants born to HIV-infected mothers were followed in a postpartum clinic. ⋯ A high risk for early postpartum hospitalization was seen in replacement-fed infants born to HIV-infected mothers in Pune, India. In settings such as India, where access to safe replacement feeding is limited, interventions making exclusive breast-feeding safer for HIV-infected mothers and infants are needed. Such interventions would be valuable additions to the very effective national prevention programs that currently rely on the provision of short-course zidovudine and nevirapine.
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The Journal of nutrition · May 2003
ReviewSelenoprotein metabolism and function: evidence for more than one function for selenoprotein P.
Biological functions of selenium are exerted by selenoproteins that contain selenocysteine in their primary structure. Selenocysteine is synthesized and inserted into proteins cotranslationally by a complex process. Families of selenoproteins include the glutathione peroxidases, the iodothyronine deiodinases and the thioredoxin reductases. ⋯ Brain tissue did not begin accumulating (75)Se until (75)Se-labeled selenoprotein P had begun appearing in the plasma after 30 min. These results suggest that tissues like liver can take up small-molecule forms of selenium whereas presence of the element in selenoprotein P facilitates uptake by tissues like brain. Thus, there is evidence for both antioxidant and selenium transport functions of selenoprotein P.
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The Journal of nutrition · May 2003
Comparative StudyMethylenetetrahydrofolate reductase 677C-->T variant modulates folate status response to controlled folate intakes in young women.
A common genetic variant in the methylenetetrahydrofolate reductase (MTHFR) gene involving a cytosine to thymidine (C-->T) transition at nucleotide 677 is associated with reduced enzyme activity, altered folate status and potentially higher folate requirements. The objectives of this study were to investigate the effect of the MTHFR 677 T allele on folate status variables in Mexican women (n = 43; 18-45 y) and to assess the adequacy of the 1998 folate U. S. ⋯ Collectively, these data demonstrate that the MTHFR C-->T variant modulates folate status response to controlled folate intakes and support the adequacy of the 1998 folate U. S. RDA for all three MTHFR C677T genotypes.