BACKGROUND Vitamin A deficiency is an important dietary deficiency in the world. Thus, the ne¬cessity of screening for deficient populations is obvious. This paper introduces a fast, cheap and relatively reliable method called "dried blood spot" (DBS) method in screening the deficient populations. The validity of this method for retinol measurement was investigated. METHOD The "precision" and...

Perfusion feeding in rats induced a decrease in circulating retinol despite an adequate supply of vitamin A. We studied the effect of total parenteral nutrition (TPN) on the retinol specific carrier in rat, analyzing holo-RBP (bound to retinol) and apo-RBP (without retinol) in serum and in liver. Vitamin A-sufficient (A+) and -deficient (A-) rats were characterized in terms of vitamin A and RBP...

Although the anticarcinogenic and antiproliferative effects of vitamin A (retinol) have been extensively studied in vitro, there are few data regarding the response of human tumor cells to this agent in vivo. We have studied the effects of retinol on the human breast carcinoma cell line, MDA-MB-231. Initial in vitro studies on monolayer cultures demonstrated a retinol-induced growth inhibition ...

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...

Involucrin accumulation and ionophore-assisted envelope formation, markers of keratinocyte differentiation, were found to be highly dependent on culture conditions in the malignant epidermal keratinocyte line, SCC-13, derived from a human squamous cell carcinoma. In confluent cultures, approximately one-half of the cells were competent to form envelopes when grown in medium without hydrocortiso...

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...