Background: Micronutrients deficiency is one of the most health problems in the world. Iron and zinc deficiency and their interaction with vitamin A are important, too. The aim of this study was to investigate the effects of supplementation of iron and zinc, alone or combined, on vitamin A status of primary school children. Material and methods: The study was a randomized double-blind clinica...

When EBV-transformed human B cells are removed from conventional cell cultures, washed, and seeded at a low cell density in serum-free medium, their growth potential is greatly diminished. Fresh serum restores the growth of low density B cell cultures. We have traced this restorative effect to an essential factor present in the lipid fraction of serum and have identified it as all-trans retinol...

To understand the signaling and growth-inhibitory effects of retinoids, we have examined the metabolism of [3H]retinol in a number of estrogen receptor-positive (ER+) and estrogen receptor-negative (ER-) human breast cancer cell lines. We have also assayed the metabolism of [3H]retinol in normal human mammary epithelial cells. The ER+ breast cancer cell lines MCF-7 and T47D produce [3H]4-oxoret...

BACKGROUND The results of cross-sectional studies indicate that micronutrient deficiencies are common in patients with tuberculosis. No published data exist on the effect of vitamin A and zinc supplementation on antituberculosis treatment. OBJECTIVE Our goal was to investigate whether vitamin A and zinc supplementation increases the efficacy of antituberculosis treatment with respect to clini...

BACKGROUND Retinol isotope dilution (RID) is used to determine vitamin A total body stores (TBS) after an oral dose of a vitamin A stable isotope. The generally accepted prediction equation proposed by Olson's group in 1989 (Furr et al. Am J Clin Nutr 1989;49:713-6) includes factors related to dose absorption and retention, isotope equilibration in plasma compared with stores, catabolism during...

In two experiments, f3-carotene applied to mice initiated with 7,12-dimethylbenz[a]anthracene (DMBA), concomitantly with croton resin and croton oil, increased tumor incidence by 58 and 29%. In the same experiments, retinyl acetate reduced tumor incidence by 76 and 29%. Retinol in one experiment reduced the number of papillomas by 75%. f3-lonone, squalene, and isoprene had little or no effect o...

Chronic ethanol consumption reduces the liver retinoid store in man and rat. We have studied the effect of ethanol on some aspects of retinoid metabolism in parenchymal and nonparenchymal liver cells. Rats fed 36% of total energy intake as ethanol for 5-6 weeks had the liver retinoid concentration reduced to about one-third, as compared to pair-fed controls. The reduction in liver retinoid affe...

Bovine and human retinol-retinol-binding protein (RBP) were iodinated to high specific activity. At least 34% of the iodinated material was native and retained its retinol chromophore as judged by its characteristic ability to bind to plasma prealbumin. Bovine and human retinol-125I-RBP were found to bind specifically to intact isolated pigment epithelium cells from bovine eyes. The specific bi...

Vitamin A (retinol) is absorbed in the small intestine, stored in liver, and secreted into circulation bound to serum retinol-binding protein (RBP4). Circulating retinol may be taken up by extrahepatic tissues or recycled back to liver multiple times before it is finally metabolized or degraded. Liver exhibits high affinity binding sites for RBP4, but specific receptors have not been identified...

The influence of an excess of retinol on bone formation was studied by using cultures of embryonic-chick calvaria. Retinol decreased collagen synthesis in a dose-dependent manner, non-collagenous protein synthesis being relatively unaffected. Collagen synthesis was significantly inhibited after 24 h of culture with retinol and was progressively decreased, compared with control cultures containi...