Showing papers by "University of Zambia published in 1974"

Malabsorption in Africa.

Abstract: The most spectacular cases of malabsorption in Africa are those often presenting with gross malnutrition and are due to chronic calcific pancreatitis, ileo-caecal tuberculosis, and small-intestinal trauma or resection Subchnical malabsorption of carbohydrate is numerically a much greater problem That is usually associated with systemic infection and is not directly related to marginal malnutrition, or an abnormal jejunal mucosa (tropical enteropathy) The evidence that malnutrition produces significant malabsorption is limited to severe cases of kwashiorkor in children Megaloblastic anaemia due to dietary folate depletion is often associated with an abnormal D-xylose absorption test and the degree of impairment has been shown to correlate with the severity of the anaemia Intestinal parasites— Strongyloides stercoralis and Giardia lamblia —are occasional causes of malabsorption Adult hypolactasia is extremely common in African subjects Although that does not seem to be responsible for significant ill-health in adults, a low lactase concentration is probably important in the pathogenesis of marasmus in infants Secondary disaccharidase deficiency is an uncommon finding The evidence for the existence of tropical sprue in Africa has been reviewed It is rare in Europeans, compared with the high frequency in Asia There is now some evidence for the existence of chronic tropical sprue in indigenous Africans but that also seems to be less common and is not as florid as it is in Asian people in Asia The reasons for those differences in incidence rates have been discussed All causes of malabsorption common to non-tropical areas must be excluded in the individual patient Of the overt clinical causes in Africa, ileo-caecal tuberculosis is the most difficult to diagnose

Key variables to incorporate in a model for development: the african case

Abstract: Since attaining independence nearly every African government has initiated a national planning exercise founded on the recognition that the technological imperatives of specialization and exchange essential for modern development require large markets, large capital investments, a broad range of natural resources, and the training of skilled manpower-all of which require mobilization of resources at least on a national level. Plans limited to allocating resources merely on a village or even on a regional level would be incapable of contributing to significant increases of productivity because such small units lack these essential prerequisites. However, the record of national planning in Africa has not been very successful in contributing to significant development (Waterston 1965). This is particularly true if development is defined-as it will be throughout this article--as increasing productivity in all sectors of the econcmy accampanied by raising the levels of living of the broadest masses of the population.1

Effect of systemic infections on glycylglycine absorption rate from the human jejunum in vivo.

Abstract: 1. Using a double-lumen tube jejunal perfusion system, the rate of glycine absorption from a glycylglycine solution (50 mmol/l) was measured in three groups of Zambian African subjects: in fifteen subjects there was no evidence of an infection (normal group); in eleven there was acute bacterial pneumonia and five had a chronic systemic infection. 2. Differences between the mean absorption rates for the three groups were not significant. 3. Glycine absorption rate has been shown previously to be increased in subjects with acute bacterial pneumonia. The present result provides further evidence that glycine and glycylglycine use separate transfer mechanisms in man, and suggests that dipeptide absorption rate is influenced to a lesser extent than that for free amino acids by systemic stimuli.

The cordierite isograd in archaean meta-sediments near yellowknife, N.W.T., Canada-variations on an experimentally established reaction

Abstract: In the Slave Craton, meta-sediments commonly exhibit broad, Abukuma-type metamorphic aureoles round late, potassic plutons. The rocks are divided into low and medium metamorphic grades by sharply-defined cordierite isograds. Comparison of mineral assemblages above and below one such isograd indicates that chlorite and muscovite were reactants. Biotite is present below the isograd, and textural relations suggest that it participated in the reaction. Micro-probe analyses of biotites in cordierite-free and cordieritebearing rocks, considered in the light of established pro-grade compositional changes, indicate that the biotite changed in composition during the reaction, supplying Si in exchange for AlIV, Fe and Mg in exchange for AlVI, and K in exchange for Na. The reaction can be balanced in a fashion consistent with all the observable evidence. The balancing operation indicates that abundant quartz and traces of albite and ilmenite also reacted, and that biotite became more abundant during the reaction. Thus the complex reaction can be approximated by the formula Chl+Musc+Biot(1)+Qtz [+Albite+Ilm] →Cord+Biot(2)+Water It is of a type extensively studied in experimental haplo-pelitic systems but was modified in the natural system mainly because additional phases participated. In particular, pre-existing biotite was compositionally modified and increased in amount during the reaction.

Jejunal absorption rates of glucose, glycine and glycylglycine in Zambian African adults with malnutrition.

Abstract: 1. Absorption rates of glucose (from a 200 mM solution), glycine (from a 100 mM solution), and glycylglycine (from a 50 mM solution) have been estimated in six Zambian African adults with clinical evidence of malnutrition. A double-lumen tube technique was used to determine absorption rates from a 300 mm section of jejunum in vivo. 2. Two of the subjects had ileal tuberculosis and Kaposi's sarcoma respectively. A third probably had abdominal tuberculosis. Three of them had pellagra. Mean serum albumin concentration was 24 (14–43) g/l. Absorption rates have been compared with those in Zambian Africans (control subjects), previously studied, who had no clinical evidence of malnutrition, systemic infection or of gastrointestinal disease. 3. Mean glucose, glycine and glycylglycine absorption rates in the malnourished subjects were not significantly different from those in the control subjects. Mean net water absorption rate from the glucose solution was similar in the malnourished subjects and controls; during the glycine and glycylglycine perfusions the mean net absorption rate was, however, significantly lower in the malnourished subjects (P < 0.01 and P < 0.05 respectively); mean net water transfer during the glycine perfusions was towards the jejunal lumen in the malnourished subjects. One subject with pellagra had an abnormal excretion of D-xylose after a 25 g oral load; all other tests were normal. 4. It seems probable that malnutrition must be very severe, with jejunal mucosal abnormalities, before absorption rates of glucose, glycine and glycylglycine are significantly altered. The present study does not support the view that subclinical malnutrition is important in producing malabsorption of dietary components in Zambian African subjects. Systemic bacterial infections, and raised serum γ-globulin and immunoglobulin IgG concentrations have previously been associated with an impairment of glucose absorption rate in Zambian African subjects; those factors seem much more likely than subclinical malnutrition to be relevant, in the context of absorption, in the pathogenesis of overt malnutrition.

Realization of a double-ladder operational amplifier network by CA-association

Abstract: The transfer function of a double-ladder network constrained by an infinite gain operational amplifier is realized by associating it with a C parameter (CA-association). A low-pass network can always be realized by such an association; whereas, in the realization of a transfer function with finite transmission zeros, there are some constraints.

The origin of biotite in Archaean meta-sediments near Yellowknife, N.W.T., Canada: A reply to E. H. Brown

Abstract: Dr. Brown's perceptive criticism has emphasised that problems of detail remain and pointed out some deficiencies of presentation in my paper. I hope these have now been rectified. I believe, however, that the above examination of the reaction in the light of his criteria has served only to substantiate its general validity.