oxalates and Vitamin-A-Deficiency

The intestinal uptake of [14C]oxalate, [14C]glyoxylate, and [14C]glycolate are studied in brush border membrane vesicles (BBMV) isolated from vitamin A-deficient and pair-fed control rats. The data obtained indicate that oxalate and its precursors are transported across the BBMV by passive diffusion. The intestinal uptake of glyoxylate and glycolate remains unaltered in vitamin A deficiency, while uptake rate of oxalate was significantly increased (p less than 0.01) in vitamin A-deficient rats as compared to pair-fed controls. In conclusion, the results indicate that vitamin A deficiency leads to hyperabsorption of oxalate through the gut.

Topics: Animals; Glucose; Glycolates; Glyoxylates; Jejunum; Male; Microvilli; Organ Size; Oxalates; Oxalic Acid; Rats; Rats, Inbred Strains; Sodium; Urinary Calculi; Vitamin A Deficiency

The study was conducted to investigate the effect of vitamin A, B1 and B6 deficiency on oxalate metabolism in rats. A significant hyperoxaluria was the common observation in all the three vitamin deficiencies (vitamin B6 greater than vitamin A greater than vitamin B1). The activities of hepatic glycolate oxidase and glycolate dehydrogenase were markedly enhanced in vitamin-A- and vitamin-B6-deficient rats. However, lactate dehydrogenase levels remained unaltered in these deficiencies as compared to their respective pair-fed controls. Vitamin B1 deficiency of 4 weeks' duration could augment the activity of glycolate oxidase only, with no alterations in the glycolate dehydrogenase and lactate dehydrogenase levels. Intestinal oxalate uptake studies revealed increased bio-availability of oxalate from the gut in vitamin-A- and vitamin-B6-deficient rats. Thus, the results suggest the relative contribution of both exogenous as well as endogenous oxalate in the process of calculogenesis under various nutritional stress conditions in rat.

Topics: Animals; Male; Oxalates; Rats; Rats, Inbred Strains; Urinary Calculi; Vitamin A Deficiency; Vitamin B 6 Deficiency; Vitamin B Deficiency

Topics: Animals; Biological Transport; Calcium; Intestinal Mucosa; Male; Oxalates; Oxalic Acid; Rats; Rats, Inbred Strains; Vitamin A Deficiency

Topics: Aged; Atrophy; Cicatrix; Electroretinography; Fluorescein Angiography; Fundus Oculi; Humans; Hyalin; Light Coagulation; Macular Degeneration; Middle Aged; Oxalates; Pigment Epithelium of Eye; Retinal Detachment; Retinal Diseases; Retinal Hemorrhage; Retinal Vessels; Retinitis; Vascular Diseases; Vitamin A Deficiency

Two patients had fundus albipunctatus, one of the variants of congenital stationary night blindness. Neither the white dots in the retinas of these patients nor the retarded course of dark adaptation characteristically associated with the disease could be attributed to vitamin A deficiency or raised oxalate levels since both substances were present in normal amounts. Fluorescin angiography showed multiple discrete lesions in the pigment epithelium not coincident with the ophthalmoscopically visible changes. Since the pigment epithelium is the storage site for bleached visual pigment, these findings suggest abnormalities that underlie the major functional deficit in this disease, that is, the slow recovery of retinal sensitivity.

Topics: Adult; Dark Adaptation; Electroretinography; Female; Fluorescein Angiography; Humans; Night Blindness; Oxalates; Vitamin A; Vitamin A Deficiency

Topics: Adult; Blood Proteins; Calcium; Child; Child, Preschool; Creatinine; Diet; Female; Humans; Hydrogen-Ion Concentration; Magnesium; Male; Mucoproteins; Oxalates; Phosphates; Quaternary Ammonium Compounds; Uric Acid; Urinary Calculi; Urine; Vitamin A Deficiency

Topics: Animals; Diet; Male; Oxalates; Rabbits; Urinary Bladder Calculi; Vitamin A Deficiency

Topics: Chemistry Techniques, Analytical; Child; Humans; Nutrition Disorders; Oxalates; Statistics as Topic; Thailand; Uric Acid; Urinary Bladder Calculi; Urinary Calculi; Urine; Vitamin A Deficiency