published_or_final_version / Social Work and Social Administration / Doctoral / Doctor of Philosophy

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Eucalyptus grandis and its hybrids is the most important and widely planted eucalypt in South Africa. It has a wide range of uses including pulpwood, poles, firewood, charcoal, flooring, mining, furniture and general carpentry. Conservation of plant genetic resources including those used in agriculture, horticulture and forestry has become an issue of common global concern. Cryopreservation involves the storage of plant material at ultra low temperature (-196°C). The techniques for cryopreservation currently in use are varied and include the older classical techniques and the new vitrification-based techniques. Storage of biological material at -196°C causes metabolic functions to slow down considerably and minimize biological degradation, thus allowing for long-term preservation. However, there are particular stresses associated with the freezing process, e.g., ice crystal formation and cryo-dehydration, which may severely damage the material. Tolerance to drying is the key to successful cryopreservation and is commonly used in the preparation of in vitro material for cryostorage. However, drying may result in damages and a number of stresses that may activate caspase-like proteases and trigger cell death processes such as programmed cell death and necrosis. During the drying process, the physical and physiological characteristic of the cell changes because of the removal of water and damage is reflected by the lack of resumption of normal activity upon rehydration. As part of a cryo-procedure, Eucalyptus grandis axillary buds isolated from in vitro shoots were dried over silica gel for 20 minutes. Pre-treatment of the shoots with 5mg.l-1 ABA for 5 days resulted in partial resistance of the isolated buds to water loss (76% to 45%) as compared with untreated buds (76% to 33%). Concomitantly, viability decreased from 100 to 70% for ABA treated buds and to 55% for the untreated buds. Ultrastructural examination showed cellular responses to drying, ranging from cell death, through partial disruption to organelles to apparently normal ultrastructure. The use of the vital stains, 4,6-diamidino-2-phenylindole and propidium iodide, showed that certain regions of the buds (e.g. the leaf primordia) were the most prone to drying damage. The meristem, however, appeared to survive drying and for up to 72 hours of rehydration. High Reactive Oxygen Species (ROS) activity was associated with bud excision and the drying procedure. Caspase-3-like protease activity was detected after drying and rehydration in both nonviable treated and untreated buds, but not in the hydrated controls. The Caspase-3 inhibitors Ac-DEVD-CHO, pepstatin and leupeptin partially suppressed that activity. The ultrastructural studies and the use of the vital stains provided confirmation of the beneficial effects of ABA. The detection of a caspase-3- like protease has provided some evidence that the rehydrated buds, that had ultimately died, had undergone programmed cell death. The ROS production during bud isolation which was exacerbated by the drying procedure is considered to be the trigger for the programmed cell death. Data in the present study showed the role of both necrosis and PCD in the death of the tissues of the axillary buds of E. grandis axillary buds. The data also contributed to the better understanding of the impact of cryoprocedures on these clonal tissues which are ideal propagules for forestry germplasm conservation.

Although the risk of malformations in the offspring of diabetic mothers remains the leading cause of perinatal mortality, the pathogenesis has not been elucidated. The hypothesis of this study was that protein glycation and oxygen free radicals play a role in hyperglycemia-induced malformations. CD-1 mouse embryos (0-2 somites) were cultured under hyperglycemic conditions for 48 hours with the exogenous addition of anti-glycating agents and oxygen free radical scavengers. The exogenous addition of aspirin (ASA) and D-lysine reduced significantly the malformations and embryonic glycated protein levels. Salicylate, arachidonic acid (AA), and to a lesser extent, indomethacin also exerted protective effects, but with no effect on glycated protein levels. We hypothesize that ASA, salicylate and indomethacin are protective by exerting free radical scavenging action; and ASA and D-lysine are acting as potent anti-glycating agents. Moreover, we suggest that AA may have inhibited hyperglycemia-induced malformations through the protective action of prostaglandins against free radical damage. Serum media lipid peroxidation (LPO) was reduced in the ASA and indomethacin groups possibly due to either a direct free radical scavenging action and/or the inhibitory effects of these agents on cyclooxygenase activity thereby decreasing the oxygen free radicals produced by this enzyme system. On the other hand, AA was associated with an increased level of LPO in the serum media. As the evidence has shown, the cause of hyperglycemia-induced malformations appears to be multifactorial and no one agent can completely eliminate the problem, although protective action can be exerted at different levels of the glycation-free radical cascade of tissue damage.

No description available.

Previous work relating postmortem findings with cause of death have focused on the vitreous portion of the body. This research investigated the link between phospholipids in the brainstem and cause of death. The lipids were extracted by the Folch extraction method and then separated by High Performance Thin Layer Chromatography. These techniques gave excellent separation and resolution. Results showed no link between cause of death and the type of lipids found in the brainstem after death.

This epidemiological study is a longitudinal descriptive review of the mortuary register at Benedictine Hospital, with an analysis of the trends which emerge. The descriptive component describes mortality at Benedictine Hospital during the years 1995- 2001. It describes both the actual numbers of deaths which occurred according to each sex and age group, and the causes of death as recorded in the mortuary register. The purpose of this study was twofold. First it was desired to raise AIDS awareness in the district by examining the effects of the AIDS epidemic on mortality. Second as the new district health system was being established, it was desired to develop a baseline of mortality information to be utilized for management in the Nongoma Local Municipality. In the trend analysis component of the study, first, it is assumed that most of the deaths occurred at Benedictine Hospital as it is the only health facility which handles severe illness in the Nongoma Local Municipality; therefore the number of deaths within the hospital and the population of Nongoma were used to calculate Age Specific (ASMRs) and Cause Specific Mortality Rates (CSMRs). Secondly an analysis of the age and sex distribution of deaths, ASMRs, the distribution of causes of death, and CSMRs was done. Two research questions were posed. The first research question was, has there been any change in the age distribution of death? It was demonstrated that while there was an 80% increase in the number of deaths, and although deaths increased in every age group except for the neonatal group, 80% of the increase was in the young adult ages particularly in the 20 through 39 years old age groups. By 2001 these groups were recording the largest number of deaths, 179 male deaths and 133 female deaths in the 30 through 39 years old group. Also the ASMRs of young adults had increased three to four times. The second research question was, has there been any change in the distribution of causes of death? It was demonstrated that the infectious diseases which caused the largest numbers of deaths, pulmonary tuberculosis caused 353 deaths, pneumonia 250, gastroenteritis acute and chronic 203, retro-viral disease 66, and meningitis 59, were six of the top seven causes of death in 2001. Chronic gastroenteritis, retro-viral disease, and meningitis had strengthened their position moving from the second ten into the top seven. Only trauma which was in the top five was not an infectious disease. Infectious diseases increased their share of the burden of disease from 36% in 1995 to 57% in 2001. While CSMRs for trauma and the type II non-communicable diseases were basically stable or falling, those of the infectious diseases increased three to four times. It is estimated that because the mortality pattern is similar to that of AIDS deaths in South Africa and Zimbabwe, that because it is young adult mortality that has increased and that it is infectious diseases which have increased that about 50% of mortality in Nongoma is due to AIDS. Recommendations are put forward as to how to disseminate this information and also how to institute a system to carry on monitoring mortality in Nongoma. / Thesis (M.Med.)-University of Natal, Durban, 2003.

This thesis is based on a worldwide overview (meta-analysis) of prospective observational studies of blood pressure and cholesterol, involving a centralised collection of data on over one million individuals from 59 studies, which I have co- ordinated since its inception. Analytically, the aim has been to develop and to use appropriate statistical techniques to assess the age- and sex-specific associations of usual blood pressure and of usual cholesterol with cause-specific mortality. Since the data set is uniquely large, and because appropriate methods of analysis (with full account taken of the time-dependent nature of the regression dilution bias) have been developed and used, these associations have been established more reliably. An integral part of the methodological element of the thesis has been to investigate the systematic underestimation of associations between risk factor and disease that are obtained when only a single baseline measurement is used to assess levels of such risk factors (the regression dilution bias). The extent of this bias has been investigated in each study that had repeat measurements of risk factors during follow-up. One particularly novel aspect has been the emphasis on, and methods developed to account for, the regression dilution bias in several studies simultaneously and in an appropriately time-dependent way. This thesis illustrates the extent to which random error and inappropriate statistical analysis lead to misleading conclusions concerning the importance of blood pressure and blood cholesterol, particularly in premature death. Only by studying adequate numbers of deaths (136,000 deaths among 1 million adults during 13 million person- years of follow-up) and by using appropriate statistical techniques - taking proper account of (a) the regression dilution bias; (b) the full range of blood pressure and cholesterol; (c) the opposing effects of HDL.and the remaining non-HDL cholesterol; and (d) age at death - did it become possible to provide reliable results on the true relationships between blood pressure, cholesterol fractions and vascular and other causes of death. These analyses have demonstrated reliably that, as causes of IHD death in early middle age, blood pressure and blood lipids are three to five times more important than suggested by inappropriate analyses, with no clinically relevant inverse associations with cancer or other non-vascular mortality (except, surprisingly, COPD).

Although funerals are seen as universal rituals to honor the death of a loved one, their value in facilitating the grief process is not known. The present study explored the relationships between cause of death, feelings and attitudes toward the funeral, and subsequent bereavement adjustment.

Four hundred and thirty-eight participants who had lost a close friend or family in the last 2 years completed questionnaires regarding their experiences with the funeral. Results indicated individuals emotionally close to the deceased person reported higher levels of participation in funeral rituals and greater levels of bereavement adjustment. Those emotionally distant from the deceased person reported greater satisfaction with the funeral. Individuals who viewed the deceased person as a central figure in their lives had greater participation in the funeral. Those who viewed the deceased person as a peripheral figure had higher levels of bereavement adjustment. Additionally, those who viewed the death as unpreventable reported greater satisfaction with the funeral, and had higher levels of bereavement adjustment.