Anatomy and Histology

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Browsing Anatomy and Histology by browse.metadata.advisor "Baatjes, Karin J."

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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.
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    Pelvimetry of Males from the Western Cape with Rectal Cancer: Anatomical and Clinical Implication
    (Stellenbosch : Stellenbosch University, 2020-12) Lathe, Stephanie; Baatjes, Karin J.; Forgan, T. R.; Alblas, Amanda; Stellenbosch University. Faculty of Medicine and Health Sciences. Dept. of Biomedical Sciences: Anatomy and Histology.
    ENGLISH ABSTRACT: Colorectal cancer represents an increasing healthcare burden that affects South African males more commonly than females. Surgical intervention, and specifically total mesorectal excision (TME), remains a key modality in the management of rectal cancer. This procedure occurs in the spatially restricted pelvic canal. Observations of increased difficulty during TME on South African males at the Tygerberg Academic Hospital (TH) led to the impression that they display an especially narrow pelvis. Multiple evolutionary factors, such as childbirth, thermoregulation, and bipedal locomotion, have moulded the size of the modern human pelvis, with males naturally displayinga narrower pelvis than female. Climate is geographically structured and is believed to play a pivotal role in pelvic dimensions. Population groups from lower latitudes tend to exhibit a narroweranddeeperpelves compared to those from higher latitudes.The primary aim of the study was to measure the dimensions of the bony pelvis in males from the Western Cape who have undergone potentially curative colorectal cancer surgery at TH, and to compare these results with other ecogeographical regions. Secondarily, it aimed to determine if an association exists between pelvic dimensions and morbidity documented in rectal cancers patients who have undergone a TME at TH.Pelvic size was investigated by conducting nineteen pelvimetric measurements on 3D bony pelvic reconstructions of male patients (n=158) using computed tomography data. Thereafter measurements were compared with other ecogeographical regions to investigate our relative pelvic size and relationships between latitude and pelvic dimensions using forest plots. Lastly, aone-way ANOVA with a post hoc Bonferroni test was performed to determine if significant differences occur in pelvic measurements among different groups of surgical complications. This population was found to display a relatively narrow transverse pelviccanal when compared to populations from higher latitudes, which was accompanied by an increase in anteroposterior dimensions of the canal. Some measurements were found to follow expected ecogeographical patterns. Significant differences inthe inlet anteroposterior measurement were found among patients in some surgical complication groups. However, no relationship between pelvic dimensions and patient morbidity was found.