published_or_final_version / Pharmacology / Doctoral / Doctor of Philosophy

published_or_final_version / Pharmacology / Doctoral / Doctor of Philosophy

No description available.

No description available.

Venous disease is a very common disease that affects millions of people worldwide. While some of the factors that cause the development of varicose veins are well understood, the aetiology of venous ulceration is poorly understood. It has been demonstrated that venous valve failure in the large veins is an important factor leading to the development of varicose veins, however whether similar valves exist in the very small superficial veins of the human leg, and what role these valves may have in venous disease, is unknown. Therefore, the purpose of this study is to: 1. Identify whether venous valves are present in the very small superficial veins of the human leg, and if they are present, 2. Describe the density, size distribution, morphology, and regional distribution of these microvenous valves in �normal� cadaveric legs 3. Compare the �normal� microvenous valves from cadaveric tissue with microvenous valves from pathologic legs with chronic venous disease, to answer the hypothesis that individuals that develop venous ulceration have fewer microvenous valves than the normal population. In order to examine microvenous valves, two main methods have been utilised, E12 sheet plastination and vascular casting. These methods in combination provide valuable insights into the anatomy of microvenous channels, and allow examination and quantification of the venous valves. Using several techniques, this study has shown that microvenous valves are present within the very small veins of the superficial tissue of the human leg. These microvalves have been shown to be most prevalent in the smallest of the veins, down to 18[mu]m in diameter. Approximately 60% of the valves were found to be associated with tributaries. The gaiter region was demonstrated to contain the lowest number and density of microvenous valves, significantly less that the upper or mid calf regions. In addition, the gaiter region was found to have a much lower proportion of microvalves in the most superficial veins, when compared with the other regions examined. Contrary to our hypothesis, the number and density of microvalves in venous diseased legs was not different to that of normal legs. Similarly, the size and regional distributions were also not different. However, the microvalves from the venous diseased legs were significantly stretched and incompetent, allowing retrograde flow from the large veins through to the dermal capillaries. In conclusion, this study has shown that venous valves are present in the smallest of the superficial veins of the human leg, and that their density and distribution is not different between normal and venous diseased individuals. However, the microvalves from the diseased legs were incompetent and allowed retrograde flow. The role that these valves play in normal and pathological circulation is unclear, and warrants further examination.

Avhandlar ämnet sårbildningar, det vill säga sår som uppstår på annat sätt än genom yttre våld, och främst externa sådana.

published_or_final_version / abstract / toc / Surgery / Master / Master of Surgery

This study was designed to examine two premises: that the morphological "severity" of duodenal ulcers (DU) may influence the incidence of drug mediated healing and the morphological "quality" of healing after curative therapy may influence t he duration of remission. Biopsies taken at endoscopy from five healthy volunteers and from 84 patients suffering from DU were examined by light and electron microscopy. The endoscopic and morphological appearance of the mucosa within 8mm of the DU or scar, before and up to 1 year after therapy with either sucralfate, cimetidine, pirenzipine or misoprostol are described. Irrespective of the mode of therapy or whether the biopsies were from normal, juxta-DU or scar mucosa, specimens could be divided into 2 primary morphological classes: gastric metaplastic and non-metaplastic. Based on the degree of metaplastic differentiation and nonmetaplastic degeneration, these classes were further divided into 4 sub-classes. When correlated with the incidence of healing and duration of remission, metaplasia was generally found to be a positive and degenerative nonmetaplasia a negative prognostic criterion. Scores were awarded to primary morphological criteria and weighted to give high total s to favourable (metaplastic) and low totals to non-favourable (degenerative non-metaplastic) prognostic features. The sum of scores expressed as a percentage was termed the morphological index. This proved useful as a means of correlating mucosal morphology with DU healing and duration of remission. It also facilitated comparison of morphology within and between groups of patients before and after each drug regimen. The results showed that the morphological appearance of the ulcerative mucosa influenced healing and remission outcome. Discriminant analysis was applied to the numeric data that described the juxta-DU (group 1) and scar (group 2) morphology of patients treated with cimetidine in 2 studies. Separation between healed and not healed DU was achieved in 92% of group 1 and 100% (remission - more or less than 6 months) of group 2. When applied to the juxta-DU data from patients treated with cimetidine in a third study, the formulae predicted correctly in 88% of cases. In addition to predicting outcome, the formulae were used as standards to accommodate for natural variations in the prognosis of individual DU of patients enrolled for comparative drug studies. These data show that morphological analysis may be usefully employed in duodenal ulcer therapy. / Thesis (Ph.D.)-University of Natal, Durban, 1994.

No description available.

Venous disease is a very common disease that affects millions of people worldwide. While some of the factors that cause the development of varicose veins are well understood, the aetiology of venous ulceration is poorly understood. It has been demonstrated that venous valve failure in the large veins is an important factor leading to the development of varicose veins, however whether similar valves exist in the very small superficial veins of the human leg, and what role these valves may have in venous disease, is unknown. Therefore, the purpose of this study is to: 1. Identify whether venous valves are present in the very small superficial veins of the human leg, and if they are present, 2. Describe the density, size distribution, morphology, and regional distribution of these microvenous valves in �normal� cadaveric legs 3. Compare the �normal� microvenous valves from cadaveric tissue with microvenous valves from pathologic legs with chronic venous disease, to answer the hypothesis that individuals that develop venous ulceration have fewer microvenous valves than the normal population. In order to examine microvenous valves, two main methods have been utilised, E12 sheet plastination and vascular casting. These methods in combination provide valuable insights into the anatomy of microvenous channels, and allow examination and quantification of the venous valves. Using several techniques, this study has shown that microvenous valves are present within the very small veins of the superficial tissue of the human leg. These microvalves have been shown to be most prevalent in the smallest of the veins, down to 18[mu]m in diameter. Approximately 60% of the valves were found to be associated with tributaries. The gaiter region was demonstrated to contain the lowest number and density of microvenous valves, significantly less that the upper or mid calf regions. In addition, the gaiter region was found to have a much lower proportion of microvalves in the most superficial veins, when compared with the other regions examined. Contrary to our hypothesis, the number and density of microvalves in venous diseased legs was not different to that of normal legs. Similarly, the size and regional distributions were also not different. However, the microvalves from the venous diseased legs were significantly stretched and incompetent, allowing retrograde flow from the large veins through to the dermal capillaries. In conclusion, this study has shown that venous valves are present in the smallest of the superficial veins of the human leg, and that their density and distribution is not different between normal and venous diseased individuals. However, the microvalves from the diseased legs were incompetent and allowed retrograde flow. The role that these valves play in normal and pathological circulation is unclear, and warrants further examination.