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Biomedical subjects

R A Arend

Publications and source records attributed to R A Arend.

5 recordsLinked to original sources

beta-Glucuronidase and hyperbilirubinaemia in breast-fed and formula-fed babies.

Breast milk or formula milk and serum samples from 34 breast-fed babies, 15 formula-fed babies, and their mothers were examined at 3 and 21 days of neonatal age. Infant faecal samples were obtained on day 21 only. At both ages serum total bilirubin concentrations were significantly higher in breast-fed than in formula-fed infants. Beta-glucuronidase activity in formula milk was negligible while that in human milk was considerable. Day 21 faecal beta-glucuronidase was higher in the breast-fed babies. In the breast-fed babies, serum bilirubin levels were related to concentrations of beta-glucuronidase in breast milk on both days 3 and 21 and to levels of faecal beta-glucuronidase on day 21. In 4 additional babies whose feeds were temporarily changed from breast milk to formula milk because of hyperbilirubinaemia there was a striking decrease in faecal beta-glucuronidase activity coincident with a fall in serum bilirubin. Breast milk beta-glucuronidase seems to be an important factor in the neonatal hyperbilirubinaemia of breast-fed babies.

Adult

Experimental biharzial bladder cancer: tryptophan metabolism in nonhuman primates experimentally infected with Schistosoma haematobium.

A nonhuman primate species infected with Schistosoma haematobium provided a model system for controlled studies on biharzial bladder cancer. Urinary excretion of tryptophan metabolites by capuchin monkeys (Cebus apella) was similar to that of humans when expressed per g creatinine. Liver tryptophan oxygenase activity of the capuchin monkeys was comparable to that of humans. Excretion of 3-hydroxykynurenine and 3-hydroxyanthranilic acid was elevated above control levels in capuchin monkeys infected experimentally with S. haematobium. The capuchin-S. haematobium system closely resembles the human biharziasis system and offers a reproducible laboratory model system for the controlled study of the parasitology, pathogenesis, and biochemistry of biharzial bladder cancer.

3-Hydroxyanthranilic Acid

Effects of anesthetic agents on bile pigment excretion in the rat.

Anesthesia-induced alterations in bilirubin conjugation were studied. Rats were fitted with bile duct and jugular vein catheters while anesthetized with diethyl ether, ketamine or pentobarbital. As anesthesia abated, bile was collected for the next 5 hr and analyzed for flow rate, total bilirubin excretion and bilirubin glucuronide composition. The high-performance liquid chromatography method used allowed direct analysis of bile without derivatization or extraction. Ether anesthesia was associated with a reversible suppression of diglucuronide formation and total bilirubin excretion, with reciprocal monoglucuronide changes. Bile flow and pigment excretion were variable with ketamine. Pentobarbital provided the most uniform excretion data, although the ratio of C-8:C-12 monoglucuronide varied with all drugs. These data are consistent with recently reported drug-induced alterations in hepatic uridine diphosphoglucuronic acid concentration and support the hypothesis that alterations in this substrate concentration are capable of influencing rates of hepatic glucuronide formation.

Anesthetics