Esterase activity in the guinea pig thyroid under normal and pathological conditions (vitamin A deficiency) with special regard to cyst-like structures

1977 ◽  
Vol 23 (1) ◽  
pp. 129-136
Author(s):  
Svend Kirkeby
Keyword(s):  
Vitamin A ◽  
Guinea Pig ◽  
Esterase Activity ◽  
Vitamin A Deficiency ◽  
Special Regard ◽  
Pathological Conditions

INTERRELATIONSHIP OF VITAMINS A AND C ON TISSUE UBIQUINONES AND STEROLS OF RATS AND GUINEA PIGS

1967 ◽  
Vol 45 (6) ◽  
pp. 749-756 ◽  
Author(s):  
W. E. J. Phillips
Keyword(s):  
Ascorbic Acid ◽  
Vitamin A ◽  
Vitamin C ◽  
Guinea Pig ◽  
Guinea Pigs ◽  
Vitamin A Deficiency ◽  
Secondary Effect ◽  
Vitamin C Deficiency ◽  
Vitamins A And C ◽  
Combined Deficiency

The effect of administration of ascorbic acid to normal or vitamin A-deficient rats was studied in relation to hepatic levels of ubiquinones and sterols. Similar studies were made on tissues from guinea pigs deficient in vitamin C, vitamin A, or both. Vitamin A deficiency increased the concentration of liver ubiquinones in the rat. Administration of ascorbate did not influence tissue levels of ubiquinones or sterols. Vitamin C deficiency increased the concentration of sterols but not of ubiquinones in the liver of the guinea pig. Vitamin A deficiency did not increase ubiquinones nor did a combined deficiency of vitamins A and C. A secondary effect of vitamin C deficiency in the vitamin A-deficient rat is not the cause of increased ubiquinone levels.

Effect of vitamin a deficiency on guinea pig peyer's patches

1987 ◽  
Vol 7 (5) ◽  
pp. 539-545 ◽  
Author(s):  
M.S.I. Majumder ◽  
A.K.M. Abdus Sattar ◽  
Md. Mohiduzzaman
Keyword(s):  
Vitamin A ◽  
Guinea Pig ◽  
Vitamin A Deficiency ◽  
Peyer's Patches ◽  
Peyer’S Patches

VITAMIN A DEFICIENCY AND ISOPRENOID METABOLISM

1961 ◽  
Vol 39 (5) ◽  
pp. 855-861 ◽  
Author(s):  
W. E. J. Phillips
Keyword(s):  
Vitamin A ◽  
Guinea Pig ◽  
Vitamin A Deficiency ◽  
Metabolic Defect ◽  
Isoprenoid Metabolism ◽  
Metabolic Block ◽  
Liver Homogenates

Vitamin A deficiency in the intact rat evokes an increase in liver ubiquinone and the incorporation of mevalonate into ubiquinone and squalene. This aberration is caused by a metabolic block between squalene and cholesterol. The addition of vitamin A in vitro to vitamin A deficient liver homogenates does not influence the metabolic defect. The vitamin A deficient guinea pig does not exhibit an increase in liver ubiquinone or incorporation of mevalonate into ubiquinone or squalene, but the incorporation into sterols is enhanced.

Reduced Survival of Neonates due to Vitamin A Deficiency during Pregnancy in the Guinea Pig

1991 ◽  
Vol 197 (1) ◽  
pp. 56-58 ◽  
Author(s):  
J. Apgar ◽  
A. Dulin ◽  
T. Kramer ◽  
J. C. Smith
Keyword(s):  
Vitamin A ◽  
Guinea Pig ◽  
Vitamin A Deficiency

Quantification of Vitamin A in Fortified Rapeseed, Groundnut and Soya Oils Using a Simple Portable Device: Comparison to High Performance Liquid Chromatography

2013 ◽  
Vol 83 (2) ◽  
pp. 122-128 ◽  
Author(s):  
Cécile Renaud ◽  
Jacques Berger ◽  
Arnaud Laillou ◽  
Sylvie Avallone
Keyword(s):  
High Performance Liquid Chromatography ◽  
Liquid Chromatography ◽  
Vitamin A ◽  
High Performance ◽  
Vitamin A Deficiency ◽  
Developed Countries ◽  
Portable Device ◽  
Least Developed Countries ◽  
Control Food ◽  
Assay Precision

Vitamin A deficiency is still one of the major public health problems in least developed countries. Fortification of vegetable oils is a strategy implemented worldwide to prevent this deficiency. For a fortification program to be effective, regular monitoring is necessary to control food quality in the producing units. The reference methods for vitamin A quantification are expensive and time-consuming. A rapid method should be useful for regular assessment of vitamin A in the oil industry. A portable device was compared to high-performance liquid chromatography (HPLC) for three plant oils (rapeseed, groundnut, and soya). The device presented a good linearity from 3 to 30 mg retinol equivalents per kg (mg RE.kg- 1). Its limits of detection and quantification were 3 mg RE.kg- 1 for groundnut and rapeseed oils and 4 mg RE.kg- 1 for soya oil. The intra-assay precision ranged from 1.48 % to 3.98 %, considered satisfactory. Accuracy estimated by the root mean squares error ranged from 3.99 to 5.49 and revealed a lower precision than HPLC (0.4 to 2.25). Although it offers less precision than HPLC, the device estimates quickly the vitamin A content of the tested oils from 3 or 4 to 15 mg RE.kg- 1.

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.

Vitamin A deficiency is associated with disease severity in patients with liver cirrhosis

2020 ◽  
Author(s):  
M Nagel ◽  
C Labenz ◽  
M Nguyen-Tat ◽  
N Cabezas Wallscheid ◽  
C Czauderna ◽  
...  
Keyword(s):  
Liver Cirrhosis ◽  
Vitamin A ◽  
Disease Severity ◽  
Vitamin A Deficiency
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