Vitamin A circulates in human plasma as retinol bound to a specific transport protein. This protein differs from the known low and high density plasma lipoproteins and has a hydrated density greater than 1.21. In order to study this protein, volunteers were injected intravenously with retinol-15-(14)C. Plasma was collected 1-3 days later, and the purification of retinol-binding protein (RBP) wa...

Cellular retinol-binding protein, type II (CRBP (II] is an abundant protein of the mature enterocytes of the small intestine. It has been shown to direct retinol to an acyl-CoA-independent esterifying activity that utilizes an endogenous acyl donor (Ong, D.E., Kakkad, B., and MacDonald, P.N. (1987) J. Biol. Chem. 262, 2729-2736). Here we report that this activity in intestinal microsomes will c...

INTRODUCTION The aging population is one of the main results of population demographic trends during the twentieth century and will be the hallmark of populations during this century. OBJECTIVE To assess the habitual dietary vitamin A intake and serum retinol concentration in the elderly. MATERIAL AND METHODS This is a population-based epidemiological study conducted in João Pessoa, Paraiba...

Dietary diversification has been identified as a sustainable intervention method in developing countries where subclinical vitamin A deficiency exists. Nutrition education is central to all methods of nutrition intervention including dietary diversification. The paucity of available data currently limits the effective use of nutrition education in national programs in Sri Lanka. We assessed the...

BACKGROUND Vitamin A plays a central role in epithelial integrity and immune function. Given the risk of infection after transplantation, adequate vitamin A concentrations may be important in patients with a transplant. We assessed whether there was an association between retinol concentration and all-cause mortality in renal transplant recipients. METHODS We recruited 379 asymptomatic renal ...

Vitamin A, via retinoic acid (RA), is a critical micronutrient. Normally, plasma concentrations are tightly regulated. Concentrations of vitamin A metabolites (13cis-RA, atRA) and relationships between RBP4 and retinoids have never been fully evaluated in adult patients with CKD. We measured retinoid and RBP4 concentrations in plasma and urine from 55 adult patients with CKD and 21 matched heal...

BACKGROUND Findings from epidemiologic studies examining associations of serum retinol and carotenoids with prostate cancer risk have been inconsistent. This case-control study nested in the Prostate Cancer Prevention Trial evaluated associations of serum retinol and carotenoids with total, low-, and high-grade prostate cancer risk in a highly screened study population. METHODS We used logist...

BACKGROUND The relative dose response (RDR) test, which quantifies the increase in serum retinol after vitamin A administration, is a qualitative measure of liver vitamin A stores. Particularly in preterm infants, the feasibility of the RDR test involving blood is critically dependent on small sample volumes. OBJECTIVES This study aimed to assess whether the RDR calculated with retinol-bindin...

Hepatic stellate cells store the majority of the liver's retinoid (vitamin A) reserves as retinyl esters in stellate cell lipid droplets. A study was conducted to explore the effects of differences in dietary retinoid and triglyceride intake on the composition of the stellate cell lipid droplets. Weanling rats were placed on one of five diets that differed in retinoid or triglyceride contents. ...

Spontaneously transformed mouse fibroblasts (Balb/c 3T12-3 cells) displayed an increased adhesion when cultured in the presence of 10(-6) M all-trans retinol and acquired morphological characteristics of the normal phenotype. Thus it was of interest to investigate the metabolism of [15-(14)C]retinol in this system. Within 24 hours of culture, approximately 4.25% of the [(14)C]retinol was taken ...