Retinol vitamin xerophthalmia

Retinol (= Vitamin A)] (carotene) E.V McCollum showed xerophthalmia in rats due to Vitamin A deficiency... 

Vitamin A (retinol) Prevents xerophthalmia, night blindness, growth retardation, bone abnormalities Visual pigments, morphogen... 

Vitamin A (retinol, retinal, retinoic acid—the three active forms of vitamin A, and p-carotene) function in the maintenance of reproduction, vision, promotion of growth, differen tiation and maintenance of epithelial tissues, and gene expression. A deficiency of vitamin A results in impotence, night blindness, retardation of growth, and xerophthalmia. Large amounts of vitamin A are toxic and can result in an increased incidence of frac tures. 

Protein-energy malnutrition results in functional vitamin A deficiency, with very low circulating levels of the vitamin and development of clinical signs of xerophthalmia (Section 2.4). The condition is unresponsive to the administration of vitamin A and often occurs despite adequate liver reserves of retinol. The problem is one of impaired synthesis of RBP in the liver and hence a... 

A mild infection, such as measles, commonly triggers the development of xerophthalmia in children whose vitamin A status is marginal. In addition to functional deficiency as a result of impaired synthesis of RBP (Section 2.2.3) and transthyretin in response to infection, there may be a considerable urinary loss of vitamin A because of increased renal epithelial permeability and proteinuria, permitting loss of retinol bound to RBP-transthyretin. The American Academy of Pediatrics Committee on Infectious Diseases (1993) recommended vitamin A supplements for aU children who have been hospitalized with measles. 

PROVITAMIN A (B-carotene) Occurs in carrot, tomato, and paprika. One molecule of -carotene is transformed in fiver and intestinal mucosa to two molecules of vitamin A (retinol). Lack of vitamin A injures the sight and gives xerophthalmia (turbidity) of the conjunctiva, hemeralopia (nightblindness) and increased sensitivity to infections. 

Figure 4 Global geographic distribution of xerophthalmia (X, all clinical stages) and vitamin A deficiency (VAD, serum retinol concentrations <0.70pmol/l) in preschool-aged children. From West KP Jr (2002) Extent of vitamin A deficiency among children and women of reproductive age. Journal of Nutrition.

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