Thesis (Ph.D.)--York University, 2004. Graduate Programme in Psychology. / Typescript. Includes bibliographical references (leaves 164-184). Also available on the Internet. MODE OF ACCESS via web browser by entering the following URL: http://wwwlib.umi.com/cr/yorku/fullcit?pNQ99148

I-Abstract I.1-Objectives- To grossly evaluate colonic abnormalities within the Manitoba population by determining prevalence according to; age, gender, body mass index, body weight, body length, colon length, and fecal weight. I.2-Methods- A population study of 67 medico-legal autopsies from two major teaching hospitals was performed, examining the colon for abnormalities. The colon was resected just proximal to the ileocecal valve and just distal to the recto-sigmoid junction. Once the specimen was detached it was weighed with the autopsy scale opened and the feces removed. The specimen was patted dry and re-weighed. The specimen was laid on a blue specimen photograph board where the length was measured from the cecum to terminal sigmoid/rectum and photographed digitally. The specimen was then evaluated for any abnormalities. The specimen was then placed back into the body. I.3-Results Of the 67 colons assessed, 66% had an abnormality, of which 37.3% had diverticular disease and 24% had polyps, the two most common diseases. Age was the only significant factor (p=0.004) in this study affecting prevalence. The prevalence of multiple polyps was 63% with colon length being the only significant factor (p=0.0265) in this study affecting prevalence. I.4-Conclusions A progressive risk of increased abnormality formation is noted with age. Diverticular disease and polyps have similar prediction factors and disease prevalence. Many factors are suggested in the literature to influence the prediction of abnormalities, however only age was determined to be significant in this study. Multiplicity of polyps in the colon is significantly related to colon length. / October 2007

I-Abstract I.1-Objectives- To grossly evaluate colonic abnormalities within the Manitoba population by determining prevalence according to; age, gender, body mass index, body weight, body length, colon length, and fecal weight. I.2-Methods- A population study of 67 medico-legal autopsies from two major teaching hospitals was performed, examining the colon for abnormalities. The colon was resected just proximal to the ileocecal valve and just distal to the recto-sigmoid junction. Once the specimen was detached it was weighed with the autopsy scale opened and the feces removed. The specimen was patted dry and re-weighed. The specimen was laid on a blue specimen photograph board where the length was measured from the cecum to terminal sigmoid/rectum and photographed digitally. The specimen was then evaluated for any abnormalities. The specimen was then placed back into the body. I.3-Results Of the 67 colons assessed, 66% had an abnormality, of which 37.3% had diverticular disease and 24% had polyps, the two most common diseases. Age was the only significant factor (p=0.004) in this study affecting prevalence. The prevalence of multiple polyps was 63% with colon length being the only significant factor (p=0.0265) in this study affecting prevalence. I.4-Conclusions A progressive risk of increased abnormality formation is noted with age. Diverticular disease and polyps have similar prediction factors and disease prevalence. Many factors are suggested in the literature to influence the prediction of abnormalities, however only age was determined to be significant in this study. Multiplicity of polyps in the colon is significantly related to colon length.

In familial adenomatous polyposis (FAP), inactivation of the APC gene is directly linked to the development of gastrointestinal polyps and cancer. It is likely that other epigenetic factors are involved in the malignant change of polyp to carcinoma. Previous studies have implied an abnormal bile acid profile, both in faeces and bile. In this study, using carefully matched control groups, extraction of bile acids from faeces and bile was performed and analysis was rigorously performed using Gas-liquid chromatography-Mass Spectrometry. No significant differences were found between the two groups in the profile of major bile acids. An increased faecal excretion of two minor bile acids, 5β-cholanoic acid-3α-ol-12-one and 5α-cholanoic acid-3α-ol-12-one and an increased level of 5β-cholanoic acid-3α-01-12-one in bile was found in patients with FAP. A difference in the faecal neutral sterol profile had also been suggested, but this study showed no significant difference between the two groups when matching controls are used. This study does not support the idea that there are significant differences in faecal bile acid, biliary bile acid or neutral sterol profiles between individuals with familial adenomatous polyposis and controls.

I-Abstract I.1-Objectives- To grossly evaluate colonic abnormalities within the Manitoba population by determining prevalence according to; age, gender, body mass index, body weight, body length, colon length, and fecal weight. I.2-Methods- A population study of 67 medico-legal autopsies from two major teaching hospitals was performed, examining the colon for abnormalities. The colon was resected just proximal to the ileocecal valve and just distal to the recto-sigmoid junction. Once the specimen was detached it was weighed with the autopsy scale opened and the feces removed. The specimen was patted dry and re-weighed. The specimen was laid on a blue specimen photograph board where the length was measured from the cecum to terminal sigmoid/rectum and photographed digitally. The specimen was then evaluated for any abnormalities. The specimen was then placed back into the body. I.3-Results Of the 67 colons assessed, 66% had an abnormality, of which 37.3% had diverticular disease and 24% had polyps, the two most common diseases. Age was the only significant factor (p=0.004) in this study affecting prevalence. The prevalence of multiple polyps was 63% with colon length being the only significant factor (p=0.0265) in this study affecting prevalence. I.4-Conclusions A progressive risk of increased abnormality formation is noted with age. Diverticular disease and polyps have similar prediction factors and disease prevalence. Many factors are suggested in the literature to influence the prediction of abnormalities, however only age was determined to be significant in this study. Multiplicity of polyps in the colon is significantly related to colon length.

El diagnóstico histológico de los pólipos colorrectales determina la conducta que tomará el médico especialista con el paciente. Con la aparición de nuevos pólipos en los últimos años, la clasificación histológica se ha tornado más compleja y amplia. Nuestro objetivo es actualizar los conceptos en el diagnóstico histológico de pólipos de colon de una manera clara y de fácil comprensión, especialmente para gastroenterólogos y patólogos.

Thesis (M. Med. Sc.)--University of Hong Kong, 2006.

Diss. (sammanfattning) Stockholm : Karol. inst., 2004. / Härtill 4 uppsatser.

Thesis (Ph. D.)--University of Washington, 1998. / Vita. Includes bibliographical references (leaves [145]-167).

Following colonoscopic polypectomy, US Multisociety Task Force (USMSTF) guidelines stratify patients based on risk of subsequent advanced neoplasia (AN) using number, size, and histology of resected polyps, but have only moderate sensitivity and specificity. We hypothesized that a state-of-the-art statistical prediction model might improve identification of patients at high risk of future AN and address these challenges. Data were pooled from seven prospective studies which had follow-up ascertainment of metachronous AN within 3-5 years of baseline polypectomy (combined n = 8,228). Pooled data were randomly split into training (n = 5,483) and validation (n = 2,745) sets. A prognostic model was developed using best practices. Two risk cut-points were identified in the training data which achieved a 10 percentage point improvement in sensitivity and specificity, respectively, over current USMSTF guidelines. Clinical benefit of USMSTF versus model-based risk stratification was then estimated using validation data. The final model included polyp location, prior polyp history, patient age, and number, size and histology of resected polyps. The first risk cut-point improved sensitivity but with loss of specificity. The second risk cut-point improved specificity without loss of sensitivity (specificity 46.2 % model vs. 42.1 % guidelines, p < 0.001; sensitivity 75.8 % model vs. 74.0 % guidelines, p = 0.64). Estimated AUC was 65 % (95 % CI: 62-69 %). This model-based approach allows flexibility in trading sensitivity and specificity, which can optimize colonoscopy over- versus underuse rates. Only modest improvements in prognostic power are possible using currently available clinical data. Research considering additional factors such as adenoma detection rate for risk prediction appears warranted.