Showing papers by "University of Zimbabwe published in 1985"

The use of magnesium sulphate infusions in the management of very severe tetanus.

Abstract: The use of magnesium sulphate infusions as an adjunct to the management of patients with very severe tetanus was studied in 10 subjects with persistent autonomic dysfunction despite heavy sedation. Satisfactory cardiovascular control was established in nine of these cases, and there were two deaths in the series, neither directly attributable to the tetanus itself. Haemodynamic measurements performed in six patients, showed that cardiac output was well preserved during magnesium infusions. There was a significant reduction in pulse rate (p<0.05) and systemic vascular resistance (p<0.01), with an increase in stroke volume (p<0.05). It is suggested that magnesium may be a useful adjunct to standard forms of management of such cases.

The poisoning of roots of zea ma ys by nickel ions, and the protection afforded by magnesium and calcium

Abstract: Summary The growth of seedlings oiZea mays L. has been studied in water cultures containing Ni2+, Mg2+ and Caa+ singly and in certain combinations. Root growth was reduced to half that of the controls (RG50) by as little as 01 mg I−1 Ni2+. This poisoning was prevented by 4 mg I”1 Mg2+ and by 32 mg T1 Ca2+. RG50 for Mg2+ alone was 64 mg T1 and for Ca2+ more than 1000 mg I−1. Root growth could be stopped within 8 h of exposure to 1 mg I−1 Ni2+. In the absence of Ni2+, Ca2+ protected against Mg2+ toxicity but Mg2+ did not reduce the effects when CaCl2 created osmotic loss at very high concentration. In combination, a ratio of 6:1 excess of Mg: Ca was necessary for Mg2+ to begin to reduce growth. At higher concentrations Mg2+ exerted its own toxicity despite the presence of Ca2+. When Ni2+ would otherwise have poisoned growth, Ca2+ added only to the relief of poisoning by Mg2+ if the Ca2+ was in excess by more than 4:1 over Mg2+. Thus Mg2+ appeared to be more fitted to prevent Ni2+ poisoning, yet at higher concentrations it was toxic itself, while Ca2+ could at still higher concentrations protect against both Ni2+ and Mg2+. Ni2+ poisoned growth by stiffening the expansion zone tissues and by destroying the integrity of root meristems. This latter was the first and most important toxic effect, and was achieved by arresting mitosis.

Viruses isolated from Culicoides (Diptera: Ceratopogonidae) caught at the veterinary research farm, Mazowe, Zimbabwe

Abstract: Samples of Culicoides midges were caught each month for I I months at the veterinary research farm near Harare. The insects were most abundant in the wet season and the spring. Akabane, Nyabira, African horsesickness, blue tong and Ephemeral fever viruses were isolated from various Culicoides midges.

Elderly People and Social Welfare in Zimbabwe

Abstract: The ageing of Third World populations and its implications for planning in social welfare has received little attention in the literature until now. This article explores the need radically to alter Western models of care for elderly people in an African context, arguing that in situations of mass poverty and gross economic differentiation a concentration on social welfare for urban formal sector employees is inappropriate. Zimbabwe is used as a case study. The situation of the aged in Zimbabwe is analysed from existing but scanty data, and sets of policy proposals that have relevance to the national economy and to the rural, urban and commercial farming sectors are discussed.

Metamorphic conditions in central Connemara, Ireland

Abstract: Metamorphic conditions have been estimated for an area in central Connemara that includes Cashel and Lissoughter Hill. Pressures lie in the range 3.0–6.0 kbar. Temperatures increase from 625–675°C on the N slopes of Lissoughter Hill to 650–700°C on the S slopes, to 700–750°C in the migmatized metasediments N of the Cashel ultrabasic intrusion before increasing sharply towards the contact. Away from the area adjacent to the intrusion a horizontal thermal gradient of between 30°C and 40°C/km may be inferred. Differences in the relative spatial position with increasing temperature of the staurolite-out, muscovite and quartz-out and beginning of partial melting isograds imply that the rocks exposed at the eastern end of the steep belt at Maam Cross were metamorphosed at a lower pressure than those farther W at Recess. Similarly, the stable co-existence of muscovite and quartz in the Recess area may indicate that the second sillimanite isograd dips towards the S, a condition that would be consistent with sub-vertical isotherms associated with a thermal anticline centred on the Cashel volcanic arc.

Soil Loss, Hydrological Changes, and Conservation Attitudes, in the Sabi Catchment of Zimbabwe

Abstract: The Communal Lands—occupied by peasant farmers—of the upper catchment of the Sabi River (which drains the southeastern portion of Zimbabwe) are severely deforested, overgrazed, and eroded. Siltation of the river channel has increased the risk of overbank flooding at a downstream irrigation scheme, and a rise in annual outflow from the catchment over the last three decades has additional implications for irrigation development, as well as for the availability of ground-water reserves in the areas of dryland peasant farming.In a study area within one of the Communal Lands, the average rate of soil loss from fields of gentle slope is estimated to be such that the next generation of peasant farmers will be unable to achieve crop-yields above a very low ‘subsistence’ level. The degraded environment is the inevitable consequence of the expansion of a primitive system of cultivation—in a region of low inherent potential for crop production—under the pressure of rapid population growth. While the peasants are aware of many of the consequences of their exploitative methods of land-use, and recognize the importance of basic conservation measures such as erosion-control terraces, they generally feel that remedial action is beyond their means.The effective implementation of available technical solutions to the deterioration of the land resources, will depend upon the provision of greater financial incentives for intensified production, as well as upon more positive political influences, than exist at present. The eventual stabilization of the situation is achievable only if population growth is reduced; but much might be done to improve production, and promote conservation, through field research into appropriate farming systems for peasant agriculture in the Sabi catchment and similar environments.

Naloxone does not reverse ethanol analgesia in man.

Abstract: SUMMARY 1. The effects of intravenously administered ethanol and morphine on pain threshold, reaction time, motor skills and short-term memory were investigated, and the ability of naloxone to reverse any changes was studied. 2. Morphine (loading dose 0.2 mg/kg with an infusion of 0.004 mg/kg per min) and ethanol (loading dose 0.75 ml/kg with an infusion of 0.0025 ml/kg per min) produced a similar increase in pain threshold of 6.3 (s.e.m. = 1.5, n= 8) pain units and 7.7 (s.e.m. = 1.9, n= 8) pain units, respectively. Naloxone 0.015 mg/kg produced a significant reduction in pain threshold in the morphine group, but not in the ethanol group, and there was a significant difference between the groups following naloxone (P<0.05, t-test, 7 d.f.). 3. Ethanol produced a significantly greater deterioration in motor skills than did morphine (P<0.05, t-test, 7 d.f.) and performance in both groups was improved following naloxone (P<0.05, t-test, 7 d.f.). 4. There was no significant change in the other modalities studied. 5. It is concluded that the reversal of ethanol effects by naloxone is probably due to a non-specific analeptic action rather than blockade of opioid receptors.

Intrathecal chemoprophylaxis in the prevention of central nervous system relapse in burkitt's lymphoma

Abstract: A retrospective review of patients treated for endemic Burkitt's lymphoma in Ghana was undertaken to evaluate the efficacy of intrathecal (IT) chemoprophylaxis in preventing central nervous system (CNS) relapse. Patients treated before 1974 received no IT chemoprophylaxis and those treated between 1974 and 1979 received IT methotrexate in addition to systemic chemotherapy. In patients presenting with facial disease only (Stages I-II), there was no significant difference in the frequency of CNS relapse between those receiving IT chemoprophylaxis and those not receiving any. CNS relapse was, however, significantly reduced in patients presenting with abdominal disease (Stage III) who received IT chemoprophylaxis in addition to systemic combination therapy. This was associated with an improved survival.

Effect of magnesium ions on rat pineal N-acetyltransferase (EC 2.3.1.5) activity.

Abstract: N-Acetyltransferase (NAT) activity at night and following isoproterenol treatment in intact animals was higher in rats pretreated with magnesium than in controls. This effect was probably due to enhancement of agonist binding and/or adenylate cyclase activation caused by magnesium ions. A similar effect was observed in vitro, where magnesium increased norepinephrine-stimulated NAT activity in organ-cultured pineal glands, suggesting that magnesium acts primarily on the pineal gland as opposed to some other peripheral or central site. This enhancement of NAT activity by magnesium would presumably lead to increased melatonin production; and as melatonin has been shown to decrease serum magnesium levels, a negative feedback mechanism may exist.

Cryptococcosis in Zimbabwe

Abstract: The records of 16 consecutive patients with proven cryptococcosis, admitted to the two referral hospitals in Harare over a 15-year period, were reviewed. 15 were cases of meningitis, one with spinal cord granuloma, and the 16th was an orbital osteomyelitis. There were eight children and eight adults with a marked male preponderance. There was an absence of any predisposing conditions. The common clinical signs and symptoms were headache, neck stiffness, fever, confusion or drowsiness, cranial nerve lesions and long tract signs. The diagnosis was rarely suspected on admission but was discovered during life in 15 patients, in 12 by finding the organism in the (CSF) cerebrospinal fluid, and in three by biopsy of affected tissue. 50% of patients presented with a predominance of polymorphs in the CSF. The mortality rate was very high (57%) but most died before adequate treatment could be given.

Hydroclimate development following impoundment in a tropical african man-made lake (lake robertson, zimbabwe)

Abstract: SUMMARY Lake Robertson was impounded by the Darwendale Dam which was completed in late 1976 to supplement the water supply to the City of Harare, Zimbabwe. This paper presents the results of a fortnightly sampling programme conducted on the lake between January 1976, when the lake began to form, and June 1977, when the lake was at full supply level. After an initial period of low oxygen saturation and high nutrient concentration, the lake rapidly attained stability as a warm, mesotrophic, polymictic impoundment. Factors contributing to this rapid stabilization included the lake morphometry which encouraged mixing (surface area = 81 km2, mean depth - 6 m), the clearing of vegetation within the lake basin, and the rapid filling of the impoundment. The development of the lake hydroclimate is contrasted with similar patterns in other African man-made lakes and is shown to follow the classical pattern of Initial eutrophy followed by stability leading to maturity.

Feeding ecology of impala on Starvation Island, Lake Kariba

Abstract: Data on diet, physiological condition, and foraging efficiency were collected from a population of impala confined to an island on Lake Kariba. During the study, the grass Panicum repens played a major role in impala nutrition, increasing in the diet through the dry season to attain a wet season maximum. Condition indices (Kidney Fat Index and Bone Marrow Fat Index) indicated that the food resource was not limiting during the study. Differences in these indices between sexes were explained in terms of reproductive demands. Foraging efficiency of adults (as measured by Acceptable Food Abundance) declined in the cool dry season, and corresponded to a raised browse component in the diet. In the wet season, animals devoted less of their foraging time to feeding. Diet composition and foraging efficiency were related to the nature of the Panicum resource, which was in turn controlled by water level changes. The findings are matched against current ideas on optimal foraging.

The social archeology of a juvenile facility: Unobtrusive methods in the study of institutional cultures

Abstract: The structure and culture of inmate societies have been studied using a variety of research methods. Neglected among these have been unobtrusive research methods which can provide independent sources of data to test theories or challenge existing research findings. This study uses content analysis of graffiti collected from the walls of an abandoned Massachusetts juvenile correctional facility. Informant interviews and newspaper accounts of the institution provide supplemental data. Drawing on studies of graffiti from other settings, this research attempts to reconstruct historically aspects of confinement at the Bridgewater Institute for Juvenile Guidance by focusing on dimensions which include the formation of informal groups and the changes inmates experience as they progress through sections of the institution. The analysis of graffiti provides insight into the process of socialization in correctional communities as well as attests to the usefulness of unobtrusive research methods in criminal justice.

Magnetic field dependence of hydrogenic energy levels

Abstract: The energy levels of hydrogen-like systems in arbitrary external magnetic fields are calculated using hybrid variational wave functions. Such functions enable the calculation energies for levels corresponding to n = 1 through n = 5 levels of the free hydrogen atom. We use much smaller determinants than in previously reported variational calculations. In many cases there is noticeable improvement on previously reported energies in low, intermediate and high field regimes.

Gastro-intestinal phytobezoars in Zimbabwean Africans.

Abstract: The clinical features of 10 African patients with gastro-intestinal phytobezoars are described. These were similar to those described with persimmon bezoars and we postulate that the fruit of locally found trees, also of the genus Diospyros, are responsible.

The Salience of Ethnicity in African Politics

Abstract: This is a largely theoretical paper discussing the ethnic factor in African politics. The paper gives ethnicity a psychosocial meaning and examines the development or genesis of this phenomenon from "tribe in itself" to "tribe for itself." Several hypotheses on ethnic salience are examined in an effort to establish situations or circumstances that give rise to ethnic consciousness in politics. The paper also discusses the habitat of ethnicity-whether it is in the leaders or in the masses-and makes the argument that the tribal innocence of the masses should not be celebrated. The paper concludes with a speculation regarding the future of ethnicity in African politics in the background of the Marxist suggestion that ethnicity is epiphenomenon. The argument is advanced that a worker seeking power will manipulate ethnicity no differently than his bourgeois counterpart.

Management and pregnancy outcome in eclampsia at Harare Maternity Hospital.

Abstract: 34 eclamptic patients treated at Harare Maternity Hospital during 1982 were managed by the use of diazepam to control convulsions Nepresol to control the hypertension and prompt delivery. The average dose of diazepam given prior to delivery was 45.8 mgs. 80% of Greater Harare Unit patients were delivered by emergency caesarean section. The maternal mortality rate was 4% and the perinatal mortality rate 12% for patients within the Greater Harare Unit. The major factor contributing to maternal mortality in the cases reviewed was lack of antenatal care or lack of acceptance of antenatal advice. All pregnant patients must be encouraged to book for antenatal care. The perinatal mortality is higher for unbooked patients and in those patients witha long 1st fit-delivery interval. Perinatal mortality is also related to gestational age at delivery mortality being greater in those patients delivered before 34 weeks gestation. A reduction in perinatal mortality could be achieved by all patients booking for antenatal care aiming for a short 1st fit-delivery interval and providing expert neonatal care for the pre-term infant.

Ultrastructure of the colon of Locusta migratoria

Abstract: The ultrastructure of the colon of Locusta migratoria is described. The colon is lined by a thick cuticle that, for the most part, adheres to the underlying epithelium. The cuboid epithelial cells are characterized by moderate invaginations of the apical and, to a lesser extent, basal plasma membranes; the lateral plasma membranes are relatively flat. The bulk of the mitochondria are located in the apical region of the cell and are not particularly associated with any of the plasma membranes. The basal region of the cells contains much rough endoplasmic reticulum, glycogenlike granules, and a predominance of spherical, electron-dense bodies of various sizes. Where muscle fibers make contact with the epithelium, the cells are much reduced; the cytoplasm is usually less electron-dense, and, typically, the nucleus has a thick layer of granular material associated with the inner nuclear membrane. The apical and basal plasma membranes of the reduced epithelial cells contain numerous hemidesmosomes. The apical hemidesmosomes occur in pairs around an extracellular space that contains electron-opaque material. The latter forms tonofibrillae that extend into the endocuticle. Bundles of microtubules are associated with the hemidesmosomes. The tubules traverse the cell from the apical to the basal region. The possible significance of these findings is discussed.