BACKGROUND Pancreatic insufficient cystic fibrosis (CF) patients receive vitamin A supplementation according to CF-specific recommendations to prevent deficiencies. Whether current recommendations are optimal for preventing both deficiency and toxicity is a subject of debate. We assessed the longitudinal relation between serum retinol levels and appropriate variables. METHODS We studied vitam...

A new procedure for the determination of retinol (vitamin A alcohol) in blood has been devised. It consists of direct measurement of the fluorescence of retinol (excitation 335 nm.; emission 458 nm.) in diluted serum, and is considerably more rapid than any previous method. Such measurements are feasible because the intensity of fluorescence of retinol bound to its transport protein (retinol-bi...

We have previously reported on the dependency of activated B lymphocytes for retinol. Here we confirm and extend these findings that cells deprived of retinol perish in cell culture within days, displaying neither signs of apoptosis nor of cell cycle arrest. Cell death can be prevented by physiological concentrations of retinol and retinal, but not by retinoic acid or three synthetic retinoic a...

Bovine retinol-retinol-binding protein (RBP) was isolated from serum as a free, uncomplexed protein under experimental conditions in which human, rabbit, and chicken retinol-RBP are present as tight complexes with prealbumin (thyroxine-binding protein). Purified bovine retinol-RBP formed tight complexes with purified human and chicken prealbumin in physiological ionic strength buffers as judged...

Human small intestine was found to contain a retinol-binding protein similar to the gut-specific cellular retinol-binding protein, type two [CRBP (II)], described in the rat. This newly detected human protein was immunochemically distinct from human cellular retinol binding protein previously described but immunochemically similar to rat CRBP (II). The partially purified protein bound retinol a...

Hypothyroidism and hyperthyroidism are prevalent endocrine diseases.These have significant implications for lipid synthesis, mobilization, metabolism. Retinol-binding protein 4 is a new adipokine implicated in some physiological pathological processes, such as metabolic disorders. Its elevation aids the diagnosis of thyroid problems. The present study includes 60 women with diseases; 30 them hy...

PURPOSE Interphotoreceptor retinoid-binding protein(IRBP) is a four-repeat protein found in the interphotoreceptor space. Each repeat can bind retinoids and fatty acids. The purpose of this study was to examine the effects of the single amino acid substitution, G239T, versus the wild type sequence of human IRBP Repeat 1, on ligand binding at equilibrium, ligand off rates, and protection of reti...

This analysis evaluated the association between serum retinol levels and risk of head and neck cancer (HNC) and whether the association is modulated by the use of alcohol, betel quid, or cigarette. In addition, we also examined the association between HNC risk and 2 single nucleotide polymorphisms, TTR rs1667255 and RBP4 rs10882272, that have been associated with serum retinol levels. Unconditi...

Previous studies in our laboratory showed a synergistic interaction of synthetic ligands selective for the retinoid receptors RAR and RXR in regard to teratogenic effects produced in mice (M. M. Elmazar et al., 2001, TOXICOL: Appl. Pharmacol. 170, 2-9). In the present study the influence of phytol and phytanic acid (a RXR-selective ligand) on the teratogenicity of retinol and the RAR-selective ...

Using the World Health Organization criterion, the prevalence of sub-clinical vitamin A deficiency can be assessed using plasma retinol concentrations <0.7 micromol/l. However, plasma retinol can be depressed by infection; thus, the use of this criterion alone may overestimate deficiency. In the present study, we investigated the usefulness of the acute-phase proteins (APP) alpha1-antichymotryp...