The amounts of endogenous retinyl palmitate, retinol and retinaldehyde were measured in the neural retina and retinal pigment epithelium (RPE) of predominantly cone (chicken), rod (rat) and more mixed (cat, human) retinae. The ratio of 11-cis to all-trans isomers of retinyl palmitate and retinol in the neural retina and the RPE increases progressively with the increase in diurnality of the spec...

OBJECTIVE The aim of this study was to examine the plasma retinol of children in the acute phase of pneumonia and after recovery and to investigate the association between plasma levels of retinol after recovery with socioeconomic variables, nutritional status and severity of pneumonia. METHODS A prospective cohort study which included 40 low-income hospitalized children with pneumonia, aged ...

OBJECTIVE To analyze the occurrence of anemia and iron deficiency in children aged 1 to 5 years and the association of these events and retinol deficiency. METHODS This was an observational analytic cross-sectional study conducted in Vitoria, ES, Brazil, between April and August of 2008, with healthy children aged 1 to 5 years (n=692) that lived in areas covered by primary healthcare services...

An experiment was conducted to evaluate bioavailability of five sources of vitamin A (retinol). Fifty-three yearling Angus  Brahman cattle, consisting of 39 steers and 14 heifers, were stratified by BW and gender and randomly assigned to six high concentrate diet groups receiving either no vitamin A supplementation (control), or vitamin A supplemented from the following sources: Microvit A (AD...

Studies were conducted to explore the synthesis of retinol-binding protein and transthyretin by embryonic and extraembryonic tissues during fetal development in the rat. The levels of retinol-binding protein mRNA and transthyretin mRNA were measured in fetal liver and in extraembryonic tissues by RNA gel blot analysis and hybridization with specific cDNA probes. Retinol-binding protein mRNA and...

Four experiments were conducted during 2019 and 2020 summer seasons at Weed Research Central Laboratory, Giza Ismailia Stations, to exploit of the allelochemicals potential aqueous extract derived from aboveground parts Ocimum basilicum on controlling some annual weeds growth cowpea peanut crops. Aqueous applied 40% concentration as pre-emergence and/or apportionment 30%+10%, 20%+10%+10% 10%+10...

Because vitamin A in milk is largely present as esterified retinol while blood plasma predominantly contains unesterified retinol, experiments were conducted to determine whether membranes from the lactating mammary gland are able to synthesize retinyl esters in vitro. When microsomes from rats lactating for 7 to 14 days were incubated with [(3)H]retinol dispersed in dimethylsulfoxide, some [(3...

Syrian golden hamsters were placed on a control or vitamin A-deficient diet. When their serum vitamin A content was significantly reduced, i.e., to less than 10% of controls, the hamsters were killed and lung aryl hydrocarbon hydroxylase activity and metabolism of benzo(a)pyrene were determined. The benzo(a)pyrene metabolite profile was similar with control and A-deficient systems, and only few...

The influence of feeding a pharmacological level of either selenium (SE), retinyl acetate (RA), or selenium and retinyl acetate (SE + RA) on N-methyl-N-nitrosourea-induced mammary carcinogenesis was studied in female Sprague Dawley rats. Rats received 50 mg N-methyl-N-nitrosourea per kg body weight at 50 days of age. Seven days after carcinogen treatment, groups of 25 rats each were placed on l...

There is growing need for accurate information regarding the bioavailability of carotenoids, both with respect to carotenoids per se and to the vitamin A value of provitamin A carotenoids in foods or supplement preparations. Little quantitative information is currently available, owing primarily to the lack of adequate methods to assess carotenoid bioavailability. Methods applied to xenobiotic ...