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M Cheney

Publications and source records attributed to M Cheney.

21 records · Page 2Linked to original sources

Frequency and clinical progression of the vitamin E deficiency neurologic disorder in children with prolonged neonatal cholestasis.

To determine the frequency of biochemical vitamin E deficiency and of the clinical signs of the vitamin E deficiency neurologic syndrome in children with prolonged neonatal cholestatic disorders, we studied 46 children (aged 1 month to 17.0 years) with chronic forms of intrahepatic neonatal cholestasis and 47 children (aged 4 months to 8.0 years) with extrahepatic biliary atresia. Based on serum vitamin E concentrations and the ratios of serum vitamin E concentration to total serum lipid concentration, 64% of the intrahepatic and 77% of the extrahepatic cholestasis groups were vitamin E deficient. Prior to age 1 year, neurologic function was normal in all children. Between ages 1 and 3 years, neurologic abnormalities were present in approximately 50% of the vitamin E-deficient children; after age 3 years, neurologic abnormalities were present in all vitamin E-deficient children. Areflexia was the first abnormality to develop between ages 1 and 4 years; truncal and limb ataxia, peripheral neuropathy, and ophthalmoplegia developed between ages 3 and 6 years. Neurologic dysfunction progressed to a disabling combination of findings by ages 8 to 10 years in the majority of vitamin E-deficient children. Neurologic function was normal in the vitamin E-sufficient children. We conclude that vitamin E status should be evaluated in infants in whom cholestasis is diagnosed, and effective therapy should be initiated to prevent or treat vitamin E deficiency at an early age.

Adolescent↗

Oxalate uptake by everted sacs of rat colon. Regional differences and the effects of pH and ricinoleic acid.

Hyperoxaluria is a complication of disorders associated with steatorrhea. The colon is the presumed site of enhanced oxalate absorption in patients with steatorrhea. We performed studies of colonic mucosal oxalate uptake in everted sacs of rat colon to determine the kinetics of colonic oxalate transport and to evaluate the effect of both pH and ricinoleic acid, a hydroxy fatty acid, on colonic oxalate uptake. Our study demonstrated that oxalate is transported throughout the colon by passive diffusion. Tissue uptake increased linearly with increasing oxalate concentrations and was unaffected by metabolic inhibitors, oxygen deprivation, or temperature changes. There were pH-dependent regional differences of oxalate uptake both in the presence and absence of ricinoleic acid. In the absence of ricinoleic acid, the highest oxalate uptake occurred at the lower pH values (5.4 and 6.4). In the presence of ricinoleic acid oxalate uptake was enhanced at the higher pH values (7.4 and 8.4); a finding most likely related to decreased solubility of ricinoleic acid at pH 5.4 and 6.4. Intraluminal pH is an important determinant of colonic oxalate uptake in the presence and absence of ricinoleic acid.

Animals↗