scholarly journals Carotene dioxygenase (EC 1. 13. 11. 21) activity in rat intestine: effects of vitamin A deficiency and of pregnancy

1986 ◽  
Vol 56 (1) ◽  
pp. 115-122 ◽  
Author(s):  
Laurence Villard ◽  
C. J. Bates
Keyword(s):  
Vitamin A ◽  
Vitamin A Deficiency ◽  
Statistical Significance ◽  
Supernatant Fraction ◽  
Retinyl Acetate ◽  
Vitamin A Status ◽  
Severe Deficiency ◽  
Weanling Rats ◽  
The Difference ◽  
Tissue Vitamin

1. Female weanling rats were fed on a purified diet containing either no vitamin A, apart from traces present in casein (deficient groups), or the same diet containing 1.55 mg retinol as retinyl acetate/kg (control groups). In one experiment the deficient groups were given 1 μg retinol/d after 10 weeks, to permit successful reproduction under conditions of marginal vitamin A status. A proportion were mated at 11 weeks after weaning, and fetal development was permitted for 7 d or for 20 d before killing.2. Carotene dioxygenase (EC 1. 13.11.21) activity was measured in a supernatant fraction from intestinal mucosal scrapings. For each group, activity was 20–30% greater in the vitamin-A-deficient animals than in the controls, and the difference reached statistical significance for the virgin and 7 d pregnant animals in the first experiment (severe deficiency) and for the 20 d pregnant animals in the second experiment (less-severe deficiency).3. It is suggested that low tissue vitamin A levels may feedback to increase carotene dioxygenase activity, by mechanisms at present unknown, presumably to ensure a more efficient use of precursor dietary carotenoids.

scholarly journals Impaired T lymphocyte immune response in vitamin A depleted rats and chicks

1989 ◽  
Vol 62 (2) ◽  
pp. 439-449 ◽  
Author(s):  
Aharon Friedman ◽  
David Sklan
Keyword(s):  
Immune Response ◽  
Vitamin A ◽  
Immune Responses ◽  
T Lymphocyte ◽  
Vitamin A Deficiency ◽  
Retinyl Acetate ◽  
Vitamin A Status ◽  
Severe Impairment ◽  
Lymphocyte Activity

Vitamin A deficiency results in decreased immune responses; the objective of the present study was to investigate the involvement of T lymphocytes in the depression of immune responses resulting from vitamin A depletion. This objective was achieved by evaluating antigen-specific T lymphocyte proliferative responses in vitro as vitamin A depletion developed. The evaluation was performed in both rat and chick to examine the generality of immune effects due to vitamin A depletion. Our findings show that vitamin A depletion led to severe impairment of T lymphocyte activity in both animal models, and that this was directly related to the vitamin A status in both species. Immune response impairment was found to precede other manifestations of vitamin A deficiency, and was rapidly corrected by feeding retinyl acetate boluses. This implied a possible regulatory, rather than constitutive, role of vitamin A in immune responsiveness.

Drought feeding of cattle. II. Comparison of daily and weekly feeding of all-grain rations: with observations on vitamin A status

1960 ◽  
Vol 11 (3) ◽  
pp. 445 ◽  
Author(s):  
WH Southcott ◽  
GL McClymont
Keyword(s):  
Vitamin A ◽  
Night Blindness ◽  
Vitamin A Deficiency ◽  
Serum Vitamin ◽  
Red Cell ◽  
Whole Wheat ◽  
Cell Counts ◽  
Vitamin A Status ◽  
Digestive Disturbance ◽  
The Difference

Hereford steers and heifers in poor store condition, and from 16 to 22 months old, were fed daily or weekly on whole wheat at the rate of 3.5 lb (estimated to supply 2.5 lb of starch equivalent) per day with the addition of 1 per cent. finely ground limestone. In one experiment of 16 weeks' duration, weights were maintained at about the same level (450 lb) in both groups. However, when the experiment terminated the cattle from the weekly fed group were livelier, had shed their winter coats to a greater extent, and showed more advanced eruption of the incisor teeth. In addition the values for haematocrit, haemoglobin, and red cell counts were significantly higher. In a second experiment over a period of 19 weeks, the average weights fell from 469 lb to 438 lb in the daily fed group and to 403 lb in the weekly fed group. The difference in liveweight was not significant. No improvement was observed in the activity or appearance of the cattle on weekly feeding on this occasion, although haematological examinations showed a trend in favour of this group. Additional experiments confirmed the practicability of weekly feeding for cattle and the relative ease with which the system could be introduced. However, weekly feeding incurred a greater risk of digestive disturbance and losses were heavier than with daily feeding. Cattle on carotene-deficient drought rations for 38 weeks showed no patent night blindness or other evidence of vitamin A deficiency, although individual serum vitamin A values fell as low as 2 µg per 100 ml.

Research Recommendations for Applying Vitamin A-Labelled Isotope Dilution Techniques to Improve Human Vitamin A Nutrition

2014 ◽  
Vol 84 (Supplement 1) ◽  
pp. 52-59 ◽  
Author(s):  
Sherry A. Tanumihardjo ◽  
Anura V. Kurpad ◽  
Janet R. Hunt
Keyword(s):  
Public Health ◽  
Vitamin A ◽  
Vitamin A Deficiency ◽  
Human Subjects ◽  
The Body ◽  
Pool Size ◽  
Serum Retinol ◽  
Vitamin A Status ◽  
Status Assessment ◽  
Total Body

The current use of serum retinol concentrations as a measurement of subclinical vitamin A deficiency is unsatisfactory for many reasons. The best technique available for vitamin A status assessment in humans is the measurement of total body pool size. Pool size is measured by the administration of retinol labelled with stable isotopes of carbon or hydrogen that are safe for human subjects, with subsequent measurement of the dilution of the labelled retinol within the body pool. However, the isotope techniques are time-consuming, technically challenging, and relatively expensive. There is also a need to assess different types of tracers and doses, and to establish clear guidelines for the use and interpretation of this method in different populations. Field-friendly improvements are desirable to encourage the application of this technique in developing countries where the need is greatest for monitoring the risk of vitamin A deficiency, the effectiveness of public health interventions, and the potential of hypervitaminosis due to combined supplement and fortification programs. These techniques should be applied to validate other less technical methods of assessing vitamin A deficiency. Another area of public health relevance for this technique is to understand the bioconversion of β-carotene to vitamin A, and its relation to existing vitamin A status, for future dietary diversification programs.

Genotype Effects on β-Carotene Conversion to Vitamin A: Implications on Reducing Vitamin A Deficiency in the Philippines

2021 ◽  
pp. 037957212110602
Author(s):  
Mark Pretzel P. Zumaraga ◽  
Jose Maria Reynaldo Apollo Arquiza ◽  
Mae Anne Concepcion ◽  
Leah Perlas ◽  
Ma. Neda Alcudia-Catalma ◽  
...  
Keyword(s):  
Vitamin A ◽  
Children And Adolescents ◽  
Vitamin A Deficiency ◽  
The Philippines ◽  
Fisher Exact Test ◽  
National Capital Region ◽  
Nutrition Survey ◽  
Vitamin A Status ◽  
Genotype Frequencies

Background: The study aimed to identify two beta-carotene 15,15′-monooxygenase (BCMO1) mutations, namely R267S and A379V, and determine their association with vitamin A status among Filipinos 6 to 19 years old respondents of the 2013 Philippine National Nutrition Survey living in the National Capital Region. Materials and Methods: This study followed cross-sectional design. Whole blood specimen was collected in the morning and was used as source of genomic DNA and serum for retinol concentration determination. Fisher exact test was performed to determine whether genotype frequencies were associated to retinol concentrations/vitamin A deficiency status. A level of P < .05 was identified as significant. Results: A total of 693 Filipino children and adolescents were included. Of the 693, there were at least 7.6% who bears the combined mutations for R267S + A379V. Association analysis showed that an inverse relationship exists between the A379V TT variant and vitamin A status. Although the exact role of these identified polymorphisms on retinol/carotenoid metabolism need to be confirmed in dedicated functional studies. Conclusion: This study has identified for the first time the presence of 2 nonsynonymous genetic variants/mutations in the coding region of BCMO1 gene. Interestingly, one of these two variants, the A379V T, was found to be associated with vitamin A status. It is, therefore, warranted to investigate the role of BCMO1 variants for the success of supplementation programs and fortification efforts among vulnerable populations in this region. Genetic variability should be considered for future provitamin A supplementation recommendations among children and adolescents in the Philippines.

scholarly journals Vitamin A Supplementation and Child Morbidity and Mortality in Developing Countries

1994 ◽  
Vol 15 (4) ◽  
pp. 1-9 ◽  
Author(s):  
George H. Beaton ◽  
Reynaldo Martorell ◽  
Kristan A. Aronson ◽  
Barry Edmonston ◽  
George McCabe. A. Catharine Ross ◽  
...  
Keyword(s):  
Vitamin A ◽  
Respiratory Infections ◽  
Vitamin A Deficiency ◽  
Meta Analysis ◽  
Clinical Signs ◽  
Vitamin A Status ◽  
Child Morbidity ◽  
Age Profile ◽  
Mortality Trials ◽  
Low Prevalence

A meta-analysis of eight mortality trials indicates that improving the vitamin A status of children aged six months to five years reduced mortality rates by about 23% in populations with at least low prevalence of clinical signs of vitamin A deficiency. The observed effect of supplementation, described in terms of relative risk (RR), was RR =0.77 (95% confidence interval 0.68–0.88; p < .001) and did not differ by sex or age. However, the number of lives saved was greater at younger ages because of higher mortality. A significant RR was shown for deaths attributed to diarrhoea and measles, but not for respiratory infection. Variability among the trials in effects was apparent, but attempts to explain it by descriptors of the population (baseline anthropometric status, prevalence of xerophthalmia, age profile, baseline mortality) were unsuccessful. Owing to the lack of data, firm conclusions could not be reached about effectiveness in children of less than six months and in settings where biochemical but not clinical evidence of vitamin A deficiency exists. Information about morbidity outcomes from about two dozen studies was reviewed. No consistent effects on frequency or prevalence of diarrhoeal and respiratory infections were found. Improvement in vitamin A status did appear to reduce severe morbidity, particularly in children with measles.

scholarly journals Cassava with enhanced β-carotene maintains adequate vitamin A status in Mongolian gerbils (Meriones unguiculatus) despite substantial cis-isomer content

2009 ◽  
Vol 102 (3) ◽  
pp. 342-349 ◽  
Author(s):  
Julie A. Howe ◽  
Bussie Maziya-Dixon ◽  
Sherry A. Tanumihardjo
Keyword(s):  
Vitamin A ◽  
Vitamin A Deficiency ◽  
Meriones Unguiculatus ◽  
Provitamin A ◽  
Carotenoid Content ◽  
Mongolian Gerbils ◽  
Serum Retinol ◽  
Vitamin A Status ◽  
Isomer Content ◽  
Β Carotene

Efforts to increase β-carotene in cassava have been successful, but the ability of high-β-carotene cassava to prevent vitamin A deficiency has not been determined. Two studies investigated the bioefficacy of provitamin A in cassava and compared the effects of carotenoid content and variety on vitamin A status in vitamin A-depleted Mongolian gerbils (Meriones unguiculatus). Gerbils were fed a vitamin A-free diet 4 weeks prior to treatment. In Expt 1, treatments (ten gerbils per group) included 45 % high-β-carotene cassava, β-carotene and vitamin A supplements (intake matched to high-β-carotene cassava group), and oil control. In Expt 2, gerbils were fed cassava feeds with 1·8 or 4·3 nmol provitamin A/g prepared with two varieties. Gerbils were killed after 4 weeks. For Expt 1, liver vitamin A was higher (P < 0·05) in the vitamin A (1·45 (sd 0·23) μmol/liver), lower in the control (0·43 (sd 0·10) μmol/liver), but did not differ from the β-carotene group (0·77 (sd 0·12) μmol/liver) when compared with the high-β-carotene cassava group (0·69 (sd 0·20) μmol/liver). The bioconversion factor was 3·7 μg β-carotene to 1 μg retinol (2 mol:1 mol), despite 48 % cis-β-carotene [(Z)-β-carotene] composition in cassava. In Expt 2, cassava feed with 4·3 nmol provitamin A/g maintained vitamin A status. No effect of cassava variety was observed. Serum retinol concentrations did not differ. β-Carotene was detected in livers of gerbils receiving cassava and supplements, but the cis-to-trans ratio in liver differed from intake. Biofortified cassava adequately maintained vitamin A status and was as efficacious as β-carotene supplementation in the gerbil model.

Vitamin A Status and Hepatic Drug Metabolism in the Rat

1973 ◽  
Vol 51 (1) ◽  
pp. 6-11 ◽  
Author(s):  
G. C. Becking
Keyword(s):  
Vitamin A ◽  
Drug Metabolism ◽  
Vitamin A Deficiency ◽  
Hepatic Drug Metabolism ◽  
Deficient Diet ◽  
Hepatic Drug ◽  
Vitamin A Status ◽  
Cytochrome P 450 ◽  
Liver Vitamin

The effect of vitamin A status on hepatic drug metabolism was studied in rats. Animals were fed diets with and without vitamin A for 20 and 25 days. Weight gains of control and deficient animals were not significantly different, whereas liver vitamin A levels had decreased to less than 10% of control animals after 20 days and were essentially zero after eating the deficient diet for 25 days. Aniline metabolism in vitro and aminopyrine metabolism in vitro and in vivo were significantly lower in male weanling rats fed a vitamin A deficient diet for 20 days. No alteration in in vitro p-nitrobenzoic acid metabolism was noted after 25 days on the test. Vitamin A deficiency did not alter microsomal protein levels or cytochrome c reductase activity but deficient animals did have a lower microsomal cytochrome P-450 content. Hepatic enzyme activities and cytochrome P-450 levels were restored to values approaching those found in control animals by feeding vitamin A deficient rats the vitamin A containing diet for 21 days. Liver vitamin A levels were markedly increased after re-feeding studies but were still significantly lower than control animals.

scholarly journals Production of chickens with marginal vitamin A deficiency

1992 ◽  
Vol 68 (1) ◽  
pp. 283-291 ◽  
Author(s):  
Clive E. West ◽  
S. Reinder Sijtsma ◽  
Harry P. F. Peters ◽  
Jan H. W. M. Rombout ◽  
Akke J. Van Der Zijpp
Keyword(s):  
Body Weight ◽  
Vitamin A ◽  
General Health ◽  
Egg Production ◽  
Narrow Range ◽  
Vitamin A Deficiency ◽  
Generation Model ◽  
Vitamin A Status ◽  
Plasma Retinol ◽  
High Level

Marginally vitamin A-deficient 1-d-old chickens capable of remaining healthy for at least 6 weeks were produced using a two-generation model. In this model, hens fed on diets with a limited vitamin A content were used to obtain 1-d-old chickens which were marginally deficient in vitamin A. Only hens with a narrow range of plasma retinol values (0.60–0.85 μmol/l) were satisfactory for this purpose. Above this range the 1-d-old chickens were not marginally vitamin A deficient. Below this range egg production and hatchability were affected to some extent depending on the degree of vitamin A deficiency. Even when egg production and hatchability remained at a high level in such birds, the 1-d-old chickens produced were not sufficiently strong to survive the first weeks of life. The advantages of the two-generation model for producing marginally vitamin A-deficient chickens are the increased uniformity and predictability of the chickens with respect to body-weight, general health and vitamin A status. However, it does take about 3 months to produce such chickens.

scholarly journals The effect of vitamin A deficiency on hepatic, renal and pulmonary glutathione S-transferase activities in the rat

1980 ◽  
Vol 188 (3) ◽  
pp. 889-893 ◽  
Author(s):  
Z H Siddik ◽  
E G Mimnaugh ◽  
M A Trush ◽  
T E Gram
Keyword(s):  
Vitamin A ◽  
Vitamin A Deficiency ◽  
Nutritional State ◽  
Glutathione S Transferase ◽  
Chemical Carcinogens ◽  
Deficient Diet ◽  
Liver Cytosol ◽  
Weanling Rats ◽  
Glutathione S Transferases ◽  
The Relationship

Feeding male weanling rats on a vitamin A-deficient diet for 6 weeks resulted in significant increases (44-57%) in glutathione S-aryl-, S-aralkyl- S-alkyl- and S-epoxidetransferase activities in the liver cytosol. Only the S-aralkyl- (27%) and S-alkyltransferase (14%) activities were significantly increased in the kidney as a result of deficiency. There was no effect on any of the pulmonary glutathione S-transferase activities. The increases in hepatic transferase activities were due primarily to increases (25-96%) in the apparent Vmax. There were no changes in the apparant Km of any of the four drug substrates employed. With 3,4-dichloronitrobenzene as the second substrate, the apparent Km for glutathione was increased by over 2-fold in vitamin A-deficient livers as compared with controls. The relationship between these results and enhanced susceptibility to chemical carcinogens in vitamin A deficiency is briefly discussed, and comparison is made between the effects of this nutritional state and pretreatment with drug inducers on the glutathione S-transferases.

scholarly journals Use of the retinol-binding protein : transthyretin ratio for assessment of vitamin A status during the acute-phase response

2000 ◽  
Vol 83 (5) ◽  
pp. 513-520 ◽  
Author(s):  
Suzanne M. Filteau ◽  
Juana F. Willumsen ◽  
Keith Sullivan ◽  
Karin Simmank ◽  
Mary Gamble
Keyword(s):  
Vitamin A ◽  
Sensitivity And Specificity ◽  
Assessment Tool ◽  
Binding Protein ◽  
Vitamin A Deficiency ◽  
Retinol Binding Protein ◽  
Serum Retinol ◽  
Vitamin A Status ◽  
Plasma Retinol

The ratio plasma retinol-binding protein (RBP) : transthyretin (TTR) has been proposed as a means to improve the assessment of vitamin A status of individuals with concurrent infection or inflammation. We have measured RBP and TTR in stored sera from South African children who had accidentally ingested kerosene. Samples were collected from these children in hospital when suffering acute inflammation and respiratory distress, and from them and neighbourhood control children 3 months later. Vitamin A status was defined by modified relative dose response (MRDR) tests of liver retinol stores at 3 months and by serum retinol concentration both when children were ill and when they were well. Illness was defined as either being in hospital or, at follow-up, as having a raised plasma α1-acid glycoprotein (AGP) level. The RBP : TTR value was significantly decreased by both illness and low liver retinol stores. When the effects on RBP : TTR of illness and vitamin A stores were considered together for the 3-month follow-up samples, only vitamin A status significantly decreased the value. We calculated sensitivity and specificity of the RBP : TTR ratio against established measures of vitamin A status using a cut-off value of 0·3 for RBP : TTR and standard cut-off values for MRDR (0·06) and plasma retinol (0·7 μmol/l). Compared with MRDR, RBP : TTR had sensitivities of 76 % and 43 % and specificities of 22 % and 81 % to detect vitamin A deficiency in hospitalized and well children respectively. Compared with plasma retinol, sensitivities were 88 % and 44 % and specificities were 55 % and 64 % in hospitalized and well children respectively. Only for the case of clinically well children with biochemical evidence of subclinical inflammation did sensitivity (62 % and 100 % against MRDR and plasma retinol respectively) and specificity (100 % and 60 % against MRDR and retinol) approach useful levels for an assessment tool. Overall, although a trend supporting the theory behind the use of the RBP : TTR for assessment of vitamin A status in infection was observed in the current study, the ratio did not provide adequate sensitivity and specificity to be a useful assessment tool.

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