Doctoral Degrees (Anatomy and Histology)

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Browsing Doctoral Degrees (Anatomy and Histology) by browse.metadata.advisor "Greyling, Linda Magdalena"

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    Assessment of health status in a 20th century skeletal collection from the Western Cape
    (2019-04) Alblas, Amanda; Friedling, Louise Jacqui; Greyling, Linda Magdalena; Stellenbosch University. Faculty of Medicine and Health Science. Dept. of Biomedical Sciences: Anatomy and Histology.
    ENGLISH ABSTRACT: Studies on the health status of skeletal remains give insight into the standard of living and survival pattern of historic populations. Analysis of trauma and pathological conditions in human skeletal remains are important in biological anthropology, explaining patterns of malnutrition, stress, disease and trauma in a population. However, the difficulty to overcome is the fact that the majority of skeletal pathological conditions are limited in their interpretive significance, since they are nonspecific and a range of stressors can cause the lesions. By analysing multiple conditions within a known population, pathological responses for specific insults can be outlined and in return help in interpretation of the frequencies and distributions within and between populations. The Kirsten Skeletal Collection, housed at Stellenbosch University, Division of Clinical Anatomy broadly represents individuals from mainly low socio-economic communities of different population groups in the Western Cape, dating throughout the 20th century. The aim of this study was to macroscopically and radiologically examine adult individuals (n=624, nmales=438, nfemales=186) in this collection for skeletal markings that included malnutrition (diet and metabolic deficiencies), osteoarthritic lesions, neoplasms, infective diseases and antemortem trauma lesions to be used as baseline information in further anthropological studies on the people of the Western Cape region. Statistically, the prevalence of specific diseases or trauma were correlated between the sexes, three different age-at-death and population groups as well as three different time periods throughout the 20th century using two-way frequency-tests and correspondence analyses. During the 20th century, many factors resulted in poverty, and "non white” people, namely the South African Black (SAB) and South African Coloured (SAC) population groups, was especially disadvantaged by the laws introduced by the ruling political party. The influx of people from rural areas during World War II to work in the manufacturing industry resulted in the already overcrowded, unsanitary informal settlements around the Cape Peninsula to be flooded, influencing the disease patterns in the communities. The results demonstrated that the lowest prevalence of metabolic deficiencies, iron deficiency anaemia (porotic hyperostosis), growth arrest signs (Harris’ lines), infections such as tuberculosis, osteomyelitis and non-specific periosteal reactions were observed in the South African White (SAW) population group. This confirms that higher socio economic societies, that escaped the unsanitary conditions associated with poor housing and overcrowding environments, were more succesfully buffering themselves from malnutrition and exposure to pathogens. Better dental health as well as dental fillings were also more associated with the SAW population group that had unrestrained access to dentists and health care facilities. In contrast, the ‘non-white’ population groups, that were supressed during the Apartheids regime, demonstrated a high prevalence of malnutrition, metabolic deficiencies, tuberculosis and trauma lesions. The difference between the higher and lower social categories was especially recognised during the late time period when the Apartheid laws of population group segregation among others, started to show results in the 1960 and 1970. Later, during the 1980s and 1990s, political unrest caused by the supressed majority, and the world due to the Apartheid laws, resulted in sanctions and lower economic opportunities for South Africa. A notable higher frequency of infective markings on bone was observed during the late time period in the study, an indication of the successful use of antibiotics during the last decades of the 20th century, which provided more time for lesions to manifest on bones due to the increased life-span of people. Studies on skeletal collections rely on the assumption that the remains represent a past community, population group or populations from a specific region and can be used as a valid comparative reference for reconstructing different aspects of skeletal biology of past people that lived in that population. The Kirsten Skeletal Collection represents adult age groups between 18 and 100, three population groups, both sexes, various time periods over the 20th century as well as known cause of death and last known residence. However, this skeletal collection relies on body donations or retention of adult unclaimed or family donated bodies under the statues of the Inspector of Anatomy, and therefore, resulted in a biased sample. This bias is perceived in the fact that the Kirsten Skeletal Collection have an overrepresentation of males, aged individuals and people with lower socio-economic status. Although three major South African population groups are represented, suggesting depiction in population variation, it is highly unequal, especially representing the overpresented heterogenous mixed population group (SAC) that lived in and around the northern townships of Cape Town. Despite limitations, in general this study of the Kirsten Skeletal Collection may represent many of the traits in the population at that time and may be useful in future studies on honours, masters and PhD level to refine region- and population specific reference data and play a supportive role in research and training of specialists. These data to be collected and interpreted in future studies, include estimation of demographic parameters (age, sex, ancestry origin) as well as human variation, trauma biomechanics and pathological conditions. If the existing predispositions of the collection are acknowledged and accounted for by the use of suitable methodology, the Kirsten Skeletal Collection holds much potential to become a valuable resource for future research projects in osteology and related fields.
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    Hyperglycaemia and its implication on the Pancreatic islet microvasculature in diabetic rat models
    (Stellenbosch : Stellenbosch University, 2020-12) Ngounou, Eleonore; Alblas, Amanda; Baatjes, Karin J.; Greyling, Linda Magdalena; Page, Benedict; Stellenbosch University. Faculty of Medicine and Health Sciences. Dept. of Biomedical Sciences: Anatomy and Histology.
    SUMMARY BACKGROUND: Despite the considerable progress made in the treatment of diabetes mellitus, vascular damage remains the leading cause of patient death. The mechanisms underlying vascular abnormalities in obesity and diabetes mellitus remain to be elucidated and may be the main cause of β-cell death. In addition, the detailed description of islet microvasculature in the pancreas is lacking in the literature; therefore, a better understanding of the characteristics of the blood vessel and the factors that maintain β-cell function is needed in clinical practice. OBJECTIVE: To describe the spatial distribution and histomorphology of islet microvasculature under the effect of hyperglycaemia in two experimental diabetic models. METHODS: Eight week old male Wistar rats (n=50) were divided into two groups that received either a standard diet (RAC) (n=20) or a high-fat diet (HFD) (n=30) for two weeks. By the end of the two weeks, altered glucose uptake was confirmed in the HFD group by an oral glucose tolerance test (OGTT). A subgroup (RAC / STZ) of the RAC group (n=10) and another (HFD / STZ) of the HFD group (n=10) then received 50 and 35mg/kg of body weight (BW) of streptozotocin (STZ) to induce type I diabetes mellitus and type II diabetes mellitus, respectively. They were kept diabetic for an additional eight weeks. The body weight and blood glucose (BGL) of the animals were recorded throughout the experimental period (88 days). Blood was collected for flow cytometry and Luminex assay before half the number of animals were sacrificed for pancreatic tissue collection for histological procedure. The remaining half was used to replicate (cast) the pancreatic vasculature by perfusion with polyurethane-based casting resin (PU4ii). Haematoxylin and Eosin (H&E) stained sections were used to assess the general morphology of pancreatic tissue. Methenamine silver and immunostaining using CD34 antibody, delineated the basement membrane and endothelial cells, respectively, of islet microvasculature. A digital camera and a nano-computed tomography (nano-CT) scanner made it possible to generate digital and 3D images. Quantitative evaluation of topographic morphometric parameters of the pancreatic vascular network in the duodenal and splenic regions of the pancreas in each experimental condition was performed using the imageJ and Volume Graphics VGStudioMax 3.0®. Reconstruction of the pancreatic vascular network was attempted using the vascular tree scale laws. RESULTS: A significant increase in the mean body weight was accompanied by a slight increase in mean BGL within 2 weeks in HFD. Streptozotocin caused the development of two diabetic models with all clinical symptoms (polyuria, polyphagia, high BGL (> 28mmol/L) and a significant decrease in body mass in both diabetic groups (26.68% and 15.54% in RAC / STZ and HFD / STZ respectively). The results of the flow cytometry and the Luminex assay validated the presence of islet vascular lesions in animals, which also justified the significant necrosis of endothelial cells, a decrease (p<0.05) in the mean percentage of the stained area of CD34 pixels in islets, and thickening of the basement membrane. The scaling law was used to obtain the relationships between 1) the length and volume of the pancreatic vascular tree up to capillary level (R2=0.693±0.053), 2) the diameter of the lumen and the blood flow in each pancreatic vascular branch (R2=0.988±0.055), and 3) the diameter and length of the branches of the vessels (R2=0.838±0.0123). CONCLUSION: This investigation has established detailed morphological features of the vasculature of the pancreas in the duodenal and splenic regions in normal and diabetic rat models. There were large differences in the structure of the pancreatic vasculature between the two regions appearing to be dictated by metabolic demand. However, there are still challenges in 3D visualisation of the capillary networks of the pancreatic vascular tree, which was the main limitation of this study.