retinol-palmitate and Nutrition-Disorders

We have studied the response of malnourished, xerophthalmic children to injections of water-miscible vitamin A to assess the most effective dose. Total dose injected was either greater than 100,000, 100,000, or 50,000 IU. Serum levels of retinol-binding protein, prealbumin, retinyl esters, and retinol were estimated. More than half the children given the largest does had exceptionally high serum retinyl esters and a high molar ratio of retinol and retinyl esters to retinol-binding protein. In no group did retinol-binding protein or prealbumin reach normal levels 24 h after dose. Eye recovery and weight gain was so good after 50,000 IU as after higher doses. The possible toxicity of retinyl esters and free retinol in serum is discussed and the level of vitamin A in normal liver is considered in relation to therapeutic doses. The role of protein deficiency in influencing response to dose is reviewed.

Topics: Child; Corneal Diseases; Diterpenes; Dose-Response Relationship, Drug; Female; Humans; Male; Nutrition Disorders; Palmitates; Retinol-Binding Proteins; Retinyl Esters; Vitamin A; Xerophthalmia

Post-mortem concentrations of hepatic retinol and retinyl esters were determined in 40 subjects aged over 65 years to assess the effects of disease and malnutrition on vitamin A reserves. Three groups of patients (mean age 79.6 years) were studied: (1) previously healthy, (2) chronically ill, (3) chronically ill and wasted. There was no significant difference in height or age between the groups, but group 3 was lighter than both group 1 (P less than 0.001) and group 2 (P less than 0.05). Free retinol and retinyl esters were measured by high pressure liquid chromatography, and the total hepatic retinol calculated. Analysis of variance showed that the three groups differed significantly (P less than 0.02) with regard to total retinol, retinyl palmitate and total retinyl ester content.

Topics: Aged; Aged, 80 and over; Animals; Autopsy; Chromatography, High Pressure Liquid; Chronic Disease; Diterpenes; Female; Humans; Liver; Male; Nutrition Disorders; Retinoids; Retinyl Esters; Vitamin A; Vitamin A Deficiency

Post-measles corneal ulceration resembling keratomalacia is frequently seen in young children in northern Nigeria. The concentration of retinol in plasma has been found to be depressed more by measles than by malnutrition. In order to determine whether this could be due to a specific influence of measles on the uptake, storage and release of retinol by the liver or its subsequent transport in the plasma, retinyl ester was administered parenterally to assess its effect on the concentration of circulating holo retinol-binding protein. A water-miscible preparation of retinyl palmitate was administered by intramuscular injection to well- and malnourished children with and without acute measles. In all cases, the concentration of both retinol and retinol-binding protein rose appreciably with 24 h of administration of the vitamin preparation. Thus the failure of post-measles corneal lesions to respond to orally or parenterally administered vitamin A would not appear to be due to the inability of such vitamin A to increase the level of circulating retinal in the plasma of children with measles.

Topics: Child, Preschool; Corneal Ulcer; Diterpenes; Humans; Infant; Injections, Intramuscular; Measles; Nigeria; Nutrition Disorders; Retinol-Binding Proteins; Retinol-Binding Proteins, Plasma; Retinyl Esters; Vitamin A