Acute acid exposure increases rabbit esophageal cell proliferation.

In the present study we examined whether an acute infusion of HCl into the esophagus of rabbits would cause an increase in esophageal cellular proliferation independent of morphologic evidence of cell injury. To examine this question, the distal two thirds of the rabbit esophagus was infused for 1 hour with either 40 mmol/L HCl or NSS (control), and cellular proliferation was studied 24 and 48 hours later by using bromodeoxyuridine (BrDu) to label the nuclei of dividing cells and ornithine decarboxylase (ODC) enzyme activity as a biochemical index of cell division. Although there was no gross or microscopic evidence of cell necrosis or mucosal inflammation 24 hours after H+ infusion, BrDu labeling of basal cell nuclei was significantly greater 24 hours after H+ infusion (31%+/-6%) as compared with that in control animals infused with NSS (15%+/-4%). This increase in labeling index was paralleled by a threefold greater ODC enzyme activity at 24 hours with H+ infusion. Rete pegs were infrequent in control tissues (4+/-4 rete pegs per 100 microm of esophageal length) or in animals examined 24 hours after acid exposure (4+/-2 rete pegs per 100 microm). However, rete pegs were very prominent 48 hours after acid infusion (22+/-6 rete pegs per 100 microm). A short exposure to acid can cause a significant increase in mucosal proliferation independent of injury, suggesting that esophageal cell acidification either directly or indirectly acts as a tissue mitogen.

Brush cytology for pancreatic carcinoma: an analysis of factors influencing results.

BACKGROUND: Despite recent advances in cytology brush design, yield of endoscopic brush cytology in suspected pancreatic carcinoma remains low. METHODS: We prospectively evaluated 32 such patients by ERCP to analyze differences in yield based on anatomic location of the pancreatic stricture, and the role of concurrent biliary stricture brush cytology, in improving the overall yield. Endoscopic brush cytology was performed on all strictures following ERCP. A final diagnosis of pancreatic carcinoma was confirmed in all patients. RESULTS: Twenty-three of the 32 patients had positive cytology for pancreatic malignancy (71.9%). Eight patients had positive brushings from biliary strictures alone (25%) and 15 had positive brushings obtained from pancreatic strictures (46.9%). The yield varied widely depending on the anatomic location of the stricture; ampullary, genu, and tail regions had low rates of positive cytology, in part due to technical factors and brush design (1 of 8, 2 of 6, and 1 of 4, respectively). Strictures of the head and body yielded high rates of positive cytology (7 of 8 and 4 of 6, respectively). CONCLUSIONS: The yield of endopancreatic brush cytology is related to the location of malignancy, with overall yield enhanced by concurrent brushing of bile duct strictures.

Comparison of rigid and flexible esophagoscopy in the diagnosis of esophageal disease: diagnostic accuracy, complications, and cost.

Rigid esophagoscopy has been used by otolaryngologists for evaluation of the esophagus for over 100 years. Few studies have examined the diagnostic accuracy of rigid esophagoscopy in patients with carcinoma of the head and neck. The goal of our study was to compare the diagnostic accuracy, complication rate, and costs of rigid esophagoscopy and flexible fiber-optic endoscopy in the evaluation of the esophagus in patients with head and neck carcinoma. We retrospectively reviewed the records of 195 patients with head and neck carcinoma who underwent both rigid esophagoscopy and flexible fiber-optic endoscopy within a 6-month period. We discovered 10 cases with discordant findings, of which 5 (50%) were esophageal carcinoma. The estimated cost was less for flexible endoscopy. No complications were reported in either procedure. Our study suggests that flexible fiber-optic endoscopy should replace rigid esophagoscopy in the evaluation of the esophagus in patients with head and neck carcinoma.

Pharmacological basis of contractile effects of peptidoleukotrienes on rabbit colonic muscularis mucosae.

The present study was designed to determine the mechanism(s) underlying the excitatory effects of several sulfidopeptide leukotrienes (LTs) on the muscularis mucosae in three regions of the rabbit colon. Proximal colonic muscularis mucosae was refractory to LTs C4, D4, and E4. In addition, it exhibited no responses to prostaglandin (PG) E2 and only a minimal contractile response to PGF2 alpha. Mid and distal colonic muscularis mucosae each responded to LTs C4, D4, and E4 and PGs E2 and F2 alpha with concentration-dependent contractions. In both regions, responses to LTD4 and LTE4 were abolished by indomethacin (10(-6) M) pretreatment. LTC4-induced responses were reduced approximately 50% by this procedure. The residual contraction to LTC4 was resistant to both tetrodotoxin (10(-6) M) and atropine (10(-6) M). In separate experiments, responses to LTC4 were also reduced by approximately 50% if LTC4 conversion to LTD4 and LTE4 was first prevented by L-serine borate (45 mM) in combination with L-cysteine (10 mM). It is concluded that proximal colonic muscularis mucosae lacks the appropriate functional excitatory LT and PG receptors. On mid and distal colonic muscularis mucosae, the actions of LTD4 and LTE4 and, in part, LTC4 are the result of PG production, whereas LTC4 has an additional direct action, possibly mediated through a selective LTC4 receptor.