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J Polito

Publications and source records attributed to J Polito.

4 recordsLinked to original sources

Factors predictive of difficult colonoscopy.

BACKGROUND: Prediction of a technically difficult colonoscopy may influence patient selection and procedure scheduling. Identification of predictive factors may be difficult because a common endpoint used to evaluate the success of colonoscopy is intubation of the cecum, which is usually achieved. The goal of this study was to examine the feasibility of using an alternative measure, time required for cecal intubation, to identify factors that can impact performance of colonoscopy. METHODS: The time required for cecal intubation was prospectively recorded for 802 consecutive outpatient colonoscopies performed by 7 experienced gastroenterologists. Patient data collected included height, weight, age, bowel habits, surgical history, and findings at colonoscopy. Forty-seven examinations that were stopped because of disease or unacceptable bowel preparation were excluded. The impact of the patient characteristics of the remaining sample of 755 patients on the median time required for cecal intubation for men and women was examined. RESULTS: Older age and female gender, body mass index < or =25.0 (regardless of gender), diverticular disease in women, and a history of constipation or reported laxative use in men were predictors of difficult colonoscopy. CONCLUSIONS: By using median time required for cecal intubation, several patient characteristics were identified that may predict technical difficulty at colonoscopy. These findings have implications for practice and teaching.

Age Factors↗

Growth and intestinal differentiation are independently regulated in HT29 colon cancer cells.

The polar-planar compound hexamethylene bisacetamide (HMBA) can inhibit HT29 colon carcinoma cell growth and induce a more benign phenotype, as defined by decreased anchorage-independent clonogenicity, loss of a cell surface malignancy marker, and decreased in vivo tumorigenicity. The principle aim of this study was to determine whether HMBA's effects on HT29 cell growth and biologic behavior correlate with effects on intestinal differentiation. Parallel studies were performed with sodium butyrate (NaBT), a potent inducer of intestinal differentiation. HT29 cell growth, proliferation, and markers of intestinal differentiation were assayed after short- and long-term treatment with HMBA, NaBT, or the combination. Both 5 mM HMBA and 5 mM NaBT were potent inhibitors of monolayer growth; in combination their effects were nearly additive. Inhibition of DNA synthesis was detectable within 6 h of treatment and was preceded by down-regulation of c-myc expression. Soft agar clonogenicity was also decreased by 90%, > 99%, and > 99% by HMBA, NaBT, and the combination, respectively. Despite these parallel effects on growth and in vitro markers of a benign phenotype, effects on intestinal differentiation were discordant. NaBT induced significant increases in membrane-associated alkaline phosphatase activity, cytosolic mucin content, PAS+/diastase-resistant cells, and ultrastructural evidence of intestinal cell differentiation. HMBA not only failed to induce markers of intestinal differentiation, but attenuated NaBT's effects when used in combination. These data suggest that growth and intestinal differentiation may be independently regulated in HT29 cells. They also suggest that expression of intestinal markers of differentiation is not a prerequisite for the acquisition of a more benign phenotype.

Acetamides↗