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Biomedical subjects

G C Cook

Publications and source records attributed to G C Cook.

At least 199 records · Page 11Linked to original sources
PubMed1972

Intestinal absorption rate of L-methionine in man and the effect of glucose in the perfusing fluid.

1. Using a double-lumen tube perfusion system the rates of absorption of L-methionine and glucose from a 30 cm segment of the jejunum were estimated in eight relatively normal Zambian African subjects. The effect of each substrate on the absorption of the other has also been investigated. The solutions perfused were given at 12.0 ml. min(-1), and contained (A) 100 m-mole l.(-1)L-methionine, (B) 100 m-mole l.(-1)L-methionine and 150 m-mole l.(-1) glucose and (C) 150 m-mole l.(-1) glucose.2. The presence of glucose in the perfusing fluid did not significantly alter the mean absorption rate of methionine; in six subjects, the rate of methionine absorption from solution B was less than from solution A, but in two there was a marked difference in the opposite direction. This may indicate an individual difference in the effect of glucose on L-methionine absorption in man. The presence of methionine in the perfusing fluid did not significantly alter the mean absorption rate of glucose.3. Five subjects had a transitory psychiatric disturbance after the investigation. The cause of this is not clear, but was probably caused by the absorption of a break-down product of methionine from the large intestine.

Adult↗
PubMed1971

Impairment of glycine absorption by glucose and galactose in man.

1. In order to investigate a possible competition for intestinal transport between amino acids and monosaccharides in man, iso-osmotic solutions containing (A) 100 m-mole glycine 1.(-1), (B) 100 m-mole glycine and 200 m-mole monosaccharide (glucose or galactose) 1.(-1), and (C) 200 m-mole monosaccharide 1.(-1), were successively perfused into the upper jejunum of twelve African Zambian patients. None had clinical evidence of malnutrition or small-intestinal disease. By using a double-lumen tube and by reference to a non-absorbable marker (polyethylene glycol, 4000), the rates of absorption of these substances have been calculated for a 30 cm jejunal segment.2. The presence of glucose and galactose produced a significant impairment (up to 50%) in the rate of absorption of glycine. There was also a significant decrease in the uptake of both monosaccharides from the solutions in which glycine was also present.3. If this observation also applies to other amino acids it could have a practical value in population groups living on high carbohydrate diets with a marginal concentration of some essential amino acids. It could have special importance when the jejunal mucosa is damaged in severe malnutrition or gastrointestinal infection. This impairment of amino acid uptake may explain the very high incidence of genetically determined lactase-deficiency in Africa.

Adolescent↗
PubMed1971

Glucose absorption kinetics in Zambian African patients with and without systemic bacterial infections.

Using a double-lumen tube perfusion system, solutions of glucose (1.0, 2.5, and 5.0 g 100ml(-1)) have been perfused into the upper jejunum of 22 Zambian African subjects in order to study their glucose absorption kinetics. None of them had clinical evidence of malnutrition or intestinal disease. In 10 there was no evidence of an infective disease (;normal' group); seven had tuberculosis; five had acute bacterial infections. The mean serum albumin concentration was significantly lower in those with infections; the mean total and gamma-globulin concentrations were significantly higher in the tuberculosis group. There was good reproducibility in triplicate assessments of glucose and water absorption rates in the individual subjects. Despite a wide scatter, the mean glucose kinetic curves were significantly flatter in those with infections than in the normal group (p<0.02). There was a significant association between glucose and water absorption rates in the individuals. D-xylose absorption was estimated in 11 subjects and there was a significant correlation between that and the glucose absorption rate. Jejunal morphology (n=9) and disaccharidase concentrations (n=6) were normal for African subjects and there were no significant associations between either of those and the absorption rates. Galactose absorption kinetics have been studied in an additional four relatively normal Zambian Africans. This study suggests that systemic bacterial infections can produce malabsorption. This may be relevant to the weight loss in patients with pulmonary tuberculosis and also to the aetiology of kwashiorkor.

Adult↗