Showing papers by "University of Zambia published in 1973"

Hormonal influences on erythrocyte catechol-O-methyl transferase activity in humans.

Abstract: Dans le cas de beaucoup de femmes prenant des contraceptifs oraux, l'activite du transferase catechole-O-methyle du globule rouge est reduite a des nivaux analogues a ceux observes dans le cas de femmes souffrant de depression non-traitee. Le depot de contraceptifs a action durable n'affecte pas d'une maniere significative l'enzyme, bien qu'elle soit reduite pendant le troisieme trimestre de la grossesse.

Zinc, lead and copper tolerance in the grass stereochlaena cameronii (stapf) clayton

Abstract: SUMMARY Stereochlaena cameronii, a grass widely distributed in south central Africa, possesses tolerance towards heavy metals. Its tolerance and accumulation of zinc, lead, copper, iron, manganese and magnesium as well as sulphur have been studied and compared with similar phenomena in two other local metal-tolerant grasses, Cynodon dactylon and Trachypogon spicatus, as well as in some herbs and trees. The grasses accumulate high levels of copper in their roots in contrast with the herbaceous plants which accumulate the metal in their leaves. Distribution of other metals between roots and leaves is variable and is related to soil composition. Heavy-metal tolerance in Stereochlaena cameronii does not appear to be dependent directly on sulphur or nitrogen metabolism. In S. cameronii from zinc-rich soil, the zinc is largely in insoluble form in the roots, but in plants from other soils about half of this metal is in soluble form.

Independent jejunal mechanisms for glycine and glycylglycine transfer in man in vivo.

Abstract: 1. Rates of absorption of glycine and glycylglycine from a 300 mm jejunal segment were compared in vivo when those compounds were given alone or together to six Zambian African subjects who had no clinical evidence of malnutrition or of gastro-intestinal disease. Solutions containing (A) glycine (100 mmol/1), (B) glycine (100 mmol/l)+glycylglycine (50 mmol/l), and (C) glycylglycine (50 mmol/l) were infused into the upper jejunum by means of a double-lumen tube perfusion system.2. Rate of absorption of glycine was significantly higher from the glycylglycine solution (C) than from the glycine solution (A). Glycine absorption rate from solution B (glycine+glycylglycine) was very similar to the sum of absorption rates of glycine from solutions A and C in each subject. Luminal disappearance rate of glycylglycine from solutions C and B were very similar; however, the rate was significantly greater than the total glycine absorption rate from solution C and indicates back-diffusion of glycine into the lumen after glycylglycine hydrolysis.3. The results are interpreted as indicating that the transport mechanisms for glycine and glycylglycine in man are partly, and possibly wholly, separate.

Comparison of absorption rates of glucose and maltose in man in vivo.

Abstract: SUMMARY 1. Using a double-lumen tube perfusion technique in vivo, the absorption rates of glucose from a glucose (200 mm011-~) and from a maltose (100 mmol 1-I) solution were measured in the proximal jejunum of six Zambian African adults. 2. In all of the subjects the rate of glucose absorption from the maltose solution was greater than that from the glucose solution. The difference between the mean rates was approximately 15% and is significant (P

Copper-induced chlorosis in Becium Homblei (De Wild.) Duvign. & Plancke

Abstract: Becium homblei (De Wild.) Duvign. & Plancke can grow on copper-contaminated soil and may accumulate high levels of the metal in its leaves. It is normally resistant to the toxic effects of copper, but some plants may show signs of chlorosis. This was shown to be due to interference by copper with iron accumulation in chloroplasts. Treatment of the soil with iron and nitrogen reduced copper uptake and re-established high levels of iron concentration in chloroplasts and also restored normal levels of chlorophyll. re]19720626

Relation between Glucose Absorption Rate and Serum Globulin Concentration in Man

Abstract: GLUCOSE absorption rate has been shown to be depressed in patients with acute and chronic systemic bacterial infections1. Similarly, the weight of D-xylose excreted after an oral load is decreased in such patients2, probably also as the result of impaired absorption. The cause of these abnormalities is unknown and they are not due to a change in jejunal morphology. Whether systemic parasitic infestations also lead to an impairment of monosaccharide absorption has not been investigated in man.

Constant time interval method for analysis of reaction rate data

Abstract: In the study of chemical kinetics, many integrated reaction rate equations have the form In [f(A) + a] = bt + c, where a, b, and c are constants and f(A) is some function of the concentration of a reactant (or product) which can be calculated from the data. The left-hand side of this equation cannot be graphed versus time if the constant a is unknown. However, it is shown that f(A2) varies linearly with f(A1) if A2 is the concentration of reactant measured at a constant time interval later than A1. The constants a and b can be determined from the linear graph. A number of specific examples are considered.

Surface fields on the source-excited dielectric wedge

Abstract: Approximate surface fields due to a plane-wave solution and a local-mode solution are compared. The plane-wave solution, which is new, is shown to agree well with experiment. The local-mode solution, which often has been applied to tapered waveguides and antennas, fails near the cutoffs of the surface waves.

Increased glycine absorption rate associated with acute bacterial infections in man.

Abstract: 1. Glycine absorption rate from a 300 mm jejunal segment was determined in vivo in four Zambian African subjects with acute, and four with chronic, respiratory infections. Glycine solutions (100, 150 and 250 mmol/l) were perfused, by means of a double-lumen tube technique. The results were compared with those for four relatively normal Zambian African subjects (‘reference’ group) previously studied. The group with acute-infections had a significantly higher mean absorption rate than the reference or chronic-infection group. 2. Glycine absorption results from a 100 mmol/l glycine solution in an additional twenty-four Zambian African subjects have also been analysed. When results for the thirty-six subjects were combined, those with acute bacterial infections had a significantly higher mean absorption rate than the normal subjects or those with chronic infections. For the twenty-one normal subjects there was a significant positive correlation between the individual absorption rates and serum total globulin and γ-globulin concentrations. 3. It seems likely that the rapid catabolism of protein associated with infection is counteracted by an increase in amino acid absorption rate. In subjects on a low-protein diet that mechanism would be limited. The deterioration in nutritional status during infections in developing countries could therefore be partly explained by the present observation.

Effects of ethinylestradiol and cyproterone acetate on androgen metabolism by the human prostate gland.

Abstract: 3H-Testosterone (10 μCi) was infused into 15 men approximately 20 min before prostatectomy. Cyproterone acetate (20 μg) was added to the infusate for 5 patients and ethinylestradiol (15 μg) for another 5. The remaining 5 received testosterone alone. Excised prostate glands were frozen and sections taken for histology. Remaining tissues were extracted by acetone and radioactive compounds separated by thin-layer chromatography. Identification was by co-chromatography with authentic compounds, re-crystallisation to constant radioactivity, and preparation of derivatives. Major metabolites from prostates of men receiving testosterone alone were 5α-dihydrotestosterone (16-35% of total radioactivity) and androstenedione (11-16% of total radioactivty). A similar pattern of metabolites was seen in prosstates from men receiving testosterone plus cyproterone acetate, but testosterone plus ethinylestradiol gave very much lower amounts of both 5-α-dihydrotestosterone and androstenedione. Ethinylestradiol, but not cypr...

The origin of biotite in archaean meta-sediments near Yellowknife, N. W. T., Canada

Abstract: Data on mineral compositions, modal proportions and textural relations are used to deduce the biotite-forming reaction in Archaean meta-greywackes and meta-pelites of a low-pressure facies series. Biotite originated by reaction of chlorite, muscovite and ilmenite, producing rutile, K-feldspar and quartz as subordinate reaction products. Chlorite composition did not change as the reaction progressed but muscovite became depleted in K and (Mg+Fe+Mn) while gaining a little Ti. The composition of biotite produced in the meta-pelites is to some extent dependent on how much biotite was formed.

Cooperation, Competition and Altruism Among Schoolchildren in Zambia

Abstract: Partant de l'hypothese que l'Africain traditionnel est plus cooperatif que l'Europeen ou le Nord-Americain - la societe occidentale orientant vers des conduites competitives - l'auteur propose a quarante garcons zambiens et quarante garcons blancs le jeu du Dilemme du Prisonnier ct un second jeu o[ugrave] chaque enfant possede le controle total du gain relatif apparent de son adversaire. Le plan experimental de type factoriel 2 × 2 × 2 utilise les variables suivantes: groupe ethnico-racial du sujet, groupe ethnico-racial de l'adversaire ainsi que deux niveaux d'apparente cooperation de l'opposant. Aucun des effets principaux ni des interactions ne fut significatif. La variance des groupes zambiens apparut significativement plus grande que celle des groupes americains-europeens dans le jeu du Dilemme du Prisonnier et surtout dans le cas d'un partenaire cooperatif. L'esprit de competition s'avera tres eleve dans tous les groupes et des experiences complementaires ne purent reveler beaucoup d'altruisme.

The crystal and molecular structure of diaquobis(acetylacetonato)nickel(ii). monohydrate

Abstract: The monoclinic form of diaquobis(acetylacetonato)nickel(II) is well known; however, the existence of the triclinic monohydrate form is not well recognized although preparations of the diaquo complex yield predominantly the monohydrated species when water is present in excess amounts. Diaquobis(acetylacetonato)nickel(II) monohydrate has a unit cell of dimensions a=9.083 A, b=11.012 A, c=7.578 A, α=95.85°, β=92.12° and γ=106.00° and contains two molecules related by a center of symmetry. 3,122 pieces of three-dimensional intensity data (CuKα) were collected using an automated diffractometer. The structure was solved by conventional Patterson and Fourier techniques and was refined by least squares methods to a conventional R of 0.09. The structure is that of the hydrate water molecule hydrogen bonded predominantly to the acetylacetone oxygens of the diaquobis(acetylacetonato)nickel(II) molecule. The structure of the diaquobis(acetylacetonato)nickel(II) molecule obtained in this study is compared to ...

On the role of lateral waves in the radiation from the dielectric wedge

Abstract: The field on the dielectric wedge is approximated by a plane-wave expansion as in [1]. Contributions from this solution to both the surface field and the radiation field are examined. Finally, an experimental radiation field is compared with the plane-wave solution and with a geometric-optical diffraction field.

Lactose absorption kinetics in Zambian African subjects.

Abstract: 1. Using a double-lumen tube perfusion system, solutions of lactose (50, 125 and 250 mmol/l) were introduced into the upper jejunum of six Zambian African subjects. By reference to a non-absorbable marker, polyethylene glycol, mol. wt 4000, the rates of absorption of lactose from each solution were calculated for a 300 mm jejunal segment. 2. In three subjects total lactase activity of the jejunal mucosa and brush-border lactase and other disaccharidase activities were estimated. The jejunal total and brush-border lactase activities were low. Jejunal morphology was normal for African subjects. 3. All subjects suffered abdominal colic and diarrhoea during and after the lactose perfusions. The kinetic curves for lactose were very shallow, and with all perfused solutions, there was a net movement of water into the jejunal lumen. The limited number of subjects, and the low and narrow range of enzyme activity, did not permit correlation between lactose absorption rate and lactase activity. 4. In Zambian African subjects with adult hypolactasia, the jejunal mucosa absorbs a very small proportion of the perfused lactose.

The developing law of air hijacking

Abstract: The frequency of hijacking events continues to underline the need to develop effective international arrangements binding on each and every state to deal with the problem of air piracy. The purpose of this paper is to examine the existing state of the law governing the unlawful seizure of aircraft and to indicate the extent to which acceptable legal solutions may be found. In the main the paper suggests the creation of an international criminal court.

Dairying in Zambia: I Reasons for the Disposal of Dairy Cows

Abstract: (1973). Dairying in Zambia: I Reasons for the Disposal of Dairy Cows. East African Agricultural and Forestry Journal: Vol. 39, No. 2, pp. 136-140.

Prediction and improvement of academic performance in a developing country

Abstract: Summary. Zambian students filled in questionnaires developed in Britain measuring efficiency of study methods and motivation, and an experimental group received tutoring in how to study efficiently. The scales proved reliable. The scores of Zambian students were significantly higher than those of a British sample. Scores on both the study methods and the motivation scales correlated significantly more highly with grades in Zambia than they did in Britain, despite the restricted range of results in many courses. The special tutoring in study methods resulted in significantly higher grades for second year students compared with a similar control group which did not receive such tutoring.

Occupational health and economic development in African countries.

Abstract: Although industrialization has resulted in diseases associated with exposures to various substances, it has also produced enormous benefits. It should be possible in underdeveloped countries to plan a program of technological development that would insure maximum health benefits with minimum injurious consequences. Several examples of first-phase industrialization that would meet these criteria are furnished.