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Nature Nov 1960
Topics: Hypervitaminosis A; Tretinoin; Vitamin A
PubMed: 13776588
DOI: 10.1038/188672b0 -
Poultry Science Mar 1986Susceptibility to vitamin A (vit A) toxicosis was compared in Single Comb White Leghorn chicks, broilers, and turkey poults by giving an aqueous vit A solution of... (Comparative Study)
Comparative Study
Susceptibility to vitamin A (vit A) toxicosis was compared in Single Comb White Leghorn chicks, broilers, and turkey poults by giving an aqueous vit A solution of varying concentrations by crop intubation. Results of these studies indicate a differential response to vit A toxicosis within breeds and across species. Pair-fed treatments clearly demonstrated that the effects of excess vit A on bone calcification were independent of anorexia. A comparison between turkey poults receiving either a constant dietary level of vit A or vit A by gavage showed that the latter markedly increased the severity of vit A. toxicosis.
Topics: Animals; Body Weight; Chickens; Poultry Diseases; Turkeys; Vitamin A
PubMed: 3703795
DOI: 10.3382/ps.0650538 -
Current Eye Research Oct 1988Many tissues which require vitamin A store the vitamin as long-chain fatty acyl esters of retinol. As part of a study designed to characterize vitamin A metabolism in...
Many tissues which require vitamin A store the vitamin as long-chain fatty acyl esters of retinol. As part of a study designed to characterize vitamin A metabolism in the lacrimal gland, which transports retinol from blood to lacrimal gland fluid, extracts from lacrimal glands of rabbits and rats were analyzed by non-aqueous high performance liquid chromatography. Retinyl linoleate, retinyl palmitate, and retinyl stearate were identified in these extracts by their co-elution with standards, their retention time relative to retinyl palmitate, and their susceptibility to hydrolysis by saponification. Retinyl palmitate was present in rabbit lacrimal gland at 51.0 +/- 10.1 ng/g tissue. After treatment of vitamin A-deficient rabbits with orally administered [11,12-3H] retinyl acetate, the radiolabeled esters retinyl linoleate, palmitate, and stearate were extracted from the lacrimal glands. These data show that the lacrimal gland stores vitamin A as fatty acyl esters of retinol.
Topics: Animals; Chromatography, High Pressure Liquid; Diterpenes; Lacrimal Apparatus; Rabbits; Retinoids; Retinyl Esters; Vitamin A; Vitamin A Deficiency
PubMed: 3229120
DOI: 10.3109/02713688809015147 -
The effect of vitamin A on the development of the craniofacial complex--an update for practitioners.The Journal of the Dental Association... Aug 1992
Review
Topics: Abnormalities, Drug-Induced; Animals; Embryonic and Fetal Development; Face; Humans; Neural Crest; Skull; Vitamin A
PubMed: 9511604
DOI: No ID Found -
Methods of Biochemical Analysis 1957
Topics: Vitamin A
PubMed: 13430363
DOI: 10.1002/9780470110201.ch2 -
The Pediatric Infectious Disease Journal Jan 1997
Clinical Trial
Topics: Humans; Infant; Respiratory Syncytial Virus Infections; Vitamin A
PubMed: 9002114
DOI: 10.1097/00006454-199701000-00024 -
Helvetica Chimica Acta Mar 1976
Topics: Cyclohexanes; Cyclohexanones; Methods; Stereoisomerism; Vitamin A
PubMed: 1254502
DOI: 10.1002/hlca.19760590222 -
European Journal of Medical Research Jun 2002We report in our present pilot study on the uptake of retinyl palmitate and its formation to retinol in buccal mucosal cells. Retinoids are able to change metaplastic... (Clinical Trial)
Clinical Trial
We report in our present pilot study on the uptake of retinyl palmitate and its formation to retinol in buccal mucosal cells. Retinoids are able to change metaplastic lesions in several tissues. Prior to any clinical evaluation it is necessary to measure its uptake in target tissues such as the buccal mucosal epithelium. In this pilot study 12 volunteers creamed the inside of their cheeks lightly with a 0.1% retinyl palmitate containing toothpaste for 10 days followed by a wash out phase. On day 0, 3, 7, 10, 17 and 21, buccal mucosal cell samples were taken from volunteers and the uptake of retinol and retinyl palmitate was determined by HPLC analysis. An uptake of vitamin A was demonstrated in all volunteers. Comparing day 0 to day 3 a significant uptake of retinyl palmitate (p<0.05) was detected and comparing day 3 to 17 and 21 a significant decrease (p<0.05) during growth and differentiation of the mucosal epithelium could be seen. The subsequently formed retinol showed an increase but no statistical significance was determined. - The uptake of retinyl palmitate and the formation to retinol led to an enrichment of vitamin A in buccal mucosal cells. In this way metaplastic alterations of the buccal mucosal epithelium might be prevented or reversed by the application of topical retinyl palmitate.
Topics: Adult; DNA; Diterpenes; Female; Humans; Male; Mouth Mucosa; Oral Hygiene; Pilot Projects; Retinyl Esters; Toothpastes; Vitamin A
PubMed: 12117664
DOI: No ID Found -
Food and Nutrition Bulletin Dec 2017The delivery of vitamin A supplements in Ethiopia has been shifting from Child Health Days (campaigns) to routine delivery via the community health services. (Comparative Study)
Comparative Study
BACKGROUND
The delivery of vitamin A supplements in Ethiopia has been shifting from Child Health Days (campaigns) to routine delivery via the community health services.
OBJECTIVE
The objective of this study was to compare the cost and effectiveness of these 2 delivery methods. No previous studies have done this.
METHODS
A mixed method approach was used. Quantitative data on costs were collected from interviews with key staff and coverage data from health facility records. Qualitative data on the 2 modalities were collected from key informants and community members from purposefully sampled communities using the 2 modalities.
RESULTS
Communities appreciated the provision of vitamin A supplements to their under 5-year-old children. The small drop in coverage that occurred as a result of the change in modality can be attributed to normal changes that occur with any system change. Advantages of campaigns included greater ease of mobilization and better coverage of older children from more remote communities. Advantages of routine delivery included not omitting children who happened to miss the 1 day per round that supplementation occurred and not disrupting the availability of other health services for the 5 to 6 days each campaign requires. The cost of routine delivery is not easy to measure nor is the cost of disruption to normal services entailed by campaigns.
CONCLUSION
Cost-effectiveness likely depends more on effectiveness than on cost. Overall, the routine approach can achieve good coverage and is sustainable in the long run, as long as the transition is well planned and implemented.
Topics: Child Health Services; Child, Preschool; Community Health Services; Cost-Benefit Analysis; Dietary Supplements; Ethiopia; Female; Humans; Infant; Male; Vitamin A; Vitamin A Deficiency
PubMed: 28528554
DOI: 10.1177/0379572117708657 -
The American Journal of Clinical... Feb 1999Deuterated retinol dilution (DRD) gives quantitative estimates of total body stores of vitamin A.
BACKGROUND
Deuterated retinol dilution (DRD) gives quantitative estimates of total body stores of vitamin A.
OBJECTIVES
In elderly people, we studied 1) the time when an oral dose of deuterated vitamin A equilibrates with body stores, 2) whether serum ratios of deuterated to nondeuterated retinol (D:H) at 3 or 6 d postdosing predicted body stores, and 3) the ability of DRD to detect changes in the size of the body vitamin A pool.
DESIGN
A 10-mg oral dose of [2H4]retinyl acetate was administered to 60-81-y-old Guatemalans (n = 47); percentage enrichment of serum retinol with deuterated retinol was determined at 1-3 time points per subject at 3, 6, 7, 14, 20, 21, and 54 d. In subjects from whom blood was obtained at 3 and 21 d (n = 15) and at 6 and 20 d (n = 9), total body stores were calculated by using the formula of Furr et al (Am J Clin Nutr 1989;49:713-6) with 21- or 20-d data and correlated with serum D:H at 3 or 6 d postdosing. Nine subjects received diets containing 982+/-20 microg RE (x+/-SEM) plus 800 microg RE as retinyl acetate supplements for 32 d. DRD, serum retinol, and relative dose response were used to assess vitamin A status before and after the intervention.
RESULTS
Deuterated retinol equilibrated with the body pool by 20 d postdosing. Vitamin A supplementation for 32 d increased body stores, although unexplained exaggerated increases were seen in some subjects. An inverse linear relation was found between estimates of body stores and serum D:H at 3 d postdosing (r = -0.75, P = 0.002); at 6 d postdosing, the correlation was weaker.
CONCLUSIONS
DRD can detect changes in total body stores of vitamin A, although factors affecting serum D:H need to be elucidated. Serum D:H 3 d postdosing might be used as an early indicator of total body stores of vitamin A, although a predictive equation will need to be developed.
Topics: Administration, Oral; Aged; Aged, 80 and over; Analysis of Variance; Deuterium; Dietary Supplements; Diterpenes; Female; Guatemala; Humans; Indicator Dilution Techniques; Male; Middle Aged; Retinyl Esters; Vitamin A
PubMed: 9989693
DOI: 10.1093/ajcn/69.2.278