Colonic mucosal pH in humans.

Mucosal pH was measured at specific anatomic segments within the colon using a flexible pH probe in patients prepared for colonoscopy. The data revealed similar pH measurements along the length of the colon, irrespective of the presence or absence of colorectal neoplasia. Patients exhibited a relatively acidic right colon; a more alkaline transverse, left, and sigmoid colon; and a relatively acidic rectum. There were no apparent gender- or age-related effects on colonic mucosal pH.

Brush cytology evaluation of lesions encountered during ERCP.

Malignant obstruction of the pancreaticobiliary system is a frequent indication for ERCP. Twenty-five patients with abnormalities suggestive of malignancy were encountered during ERCP at our institution and brush cytology was obtained. Positive cytology specimens were collected in 12 of 20 (60%) cases of malignancy causing biliary obstruction. Using a recently developed cytology brush for the biliary tree, detection of malignancy in strictures of the bile duct had a sensitivity of 50% and a specificity of 100%. Both cases of cholangiocarcinoma were diagnosed with cytology, as were 5 of 10 cases of pancreatic cancer. It is concluded that brush cytology is a diagnostically reliable, highly specific technique for malignant lesions encountered at ERCP. In experienced hands, a positive cytologic result may obviate the need for additional invasive diagnostic studies.