A study of the role of serotonin in the anxiolytic effect of nitrous oxide in rodents.

Rationale: In earlier studies, we have shown that nitrous oxide (N2O)-induced behavioral effects in rats and mice are mediated by benzodiazepine receptors.

Objectives: This two-part study was conducted in order to investigate the possible role of serotonin (5-HT) in the behavioral effects of N2O by clarifying its effects on regional brain concentrations of 5-HT and assessing the influence of 5-HT antagonist and reuptake inhibiting drugs on the anxiolytic-like behavioral effect of N2O.

Methods: In experiment A, male, 150-200 g Sprague-Dawley rats were killed following a 15-min exposure to room air or 70% N2O.

Endoscopic localization and management of colonic bleeding in patients with portal hypertension.

In patients with portal hypertension, vascular lesions in the colon may develop that have been collectively termed portal hypertensive colopathy. Endoscopic diagnosis of these lesions is now established, but the management of hemorrhage from them is not. We report five cases of endoscopic management of bleeding colonic vascular lesions in patients with portal hypertension.

Prognostic significance of postchemoradiation stage following preoperative chemotherapy and radiation for advanced/recurrent rectal cancers.

Purpose: To evaluate the prognostic significance of postchemoradiation pathologic stage and implications for further therapy following preoperative chemoradiation and surgery for advanced/recurrent rectal cancer.

Methods And Materials: Seventy-seven patients with advanced (fixed or tethered T4) or recurrent rectal cancer were treated with preoperative chemoradation followed by surgical resection of disease. Chemotherapy consisted of either of bolus 5-FU 500 mg/m(2) per day or continuous venous infusion 225 mg/m(2) per day for the duration of radiation.

Preoperative chemoradiation in fixed distal rectal cancer: dose time factors for pathological complete response.

Purpose: Preoperative chemoradiation is being utilized extensively in the treatment of rectal cancer. However, a variety of dose time factors in both delivery of chemotherapy and irradiation remain to be established. This study was undertaken to examine the impact of dose time factors on pathological complete response (pCR) rates following preoperative chemoradiation for fixed rectal cancer.

Intraoperative endoscopy for recurrent gastrointestinal bleeding.

We report a case series of patients with significant recurrent gastrointestinal bleeding. All forms of nonoperative investigation, diagnostic celiotomy, and even resection of portions of the gastrointestinal tract were used unsuccessfully to find the lesions. Using a modification of Bowden's technique of intraoperative endoscopy with transillumination, the nonpalpable lesions were identified and treated successfully.

The influence of uremia and immunosuppression on an animal model for ischemic colitis.

Up to 1 percent of renal transplant recipients have been reported to develop ischemic colitis. Immunosuppressive agents and uremia have been implicated in the development of this complication, but their exact relationship remains unclear. A rat model was developed to determine the effects of uremia alone and in combination with immunosuppression on the development of ischemic colitis.

Ischemic colitis and immunosuppression. An experimental model.

The incidence of ischemic colitis in renal transplant recipients approaches 1 percent. The mortality in these patients with ischemic colitis is nearly 70 percent. Immunosuppressive agents have been implicated in the development of ischemic colitis.

Recurrent appendiceal colic.

From 1962 through 1983, 1,869 appendectomies were performed at our institution. Careful review disclosed 11 patients (0.6 per cent) who had an appendectomy for recurrent pain in the right lower abdominal quadrant not associated with other classical symptoms of appendicitis.

Brachial artery puncture: a definite risk to the hand.

We have described a patient who had an acutely ischemic hand after brachial artery puncture in the antecubital fossa. Because of the anatomy of the forearm, hematoma formation and compression of the brachial artery and median nerve are poorly tolerated and predispose to irreversible ischemia or neuropathy. We recommend that brachial artery puncture in the antecubital fossa be avoided.

Characterization of a common antigen of colorectal and mucinous ovarian tumors, COTA.

A new colon cancer antigen is reported. It is designated as COTA, Colon-Ovarian Tumor Antigen, because it is found in mucins produced by both tissues during malignancy. The new antigen was identified by making antibodies against human colon cancer tissue in goats.

Ischemic colitis in rats.

Left-sided ischemic colitis was induced in 44 inbred Male Fischer rats of the same age by a standardized devascularization procedure. Fifteen animals had nothing else done (Group I). Twenty-nine animals had feces evacuated from the left colon and received an enema just before the procedure; 14 had a sterile-water enema (Group II), and 15 had a 1 per cent hydrocortisone enema (Group III).

Experimental colitis as a promoter in large-bowel tumorigenesis.

To study the effect of acetic acid colitis on 1,2-dimethylhydrazine-induced colon tumorigenesis, fischer 344 male rats, 10 weeks of age, were divided into three groups: one receiving 5% acetic acid enema (subgroup 1a); one receiving 10% acetic acid enema (subgroup 1b); and one not receiving acetic acid enema (group 2). Colitis developed in rats in groups 1a and 1b, resulting in early death in some cases. Rats of all three groups received the same subcutaneous dose of dimethylhydrazine given once a week for 20 weeks starting at 11 weeks of age; they were killed at 31 weeks after the first dimethylhydrazine injection.

Massive rectal bleeding of colonic origin: localization of the bleeding site.

Fourteen patients with massive colonic bleeding underwent preoperative evaluation including visceral angiography and/or colonoscopy. Segmental for subtotal colectomy was performed in each case. The freshly excised colonic specimen was opened and washed clean, and the mucosal surface was closely examined by manually compressing the specimen segment by segment in order to detect the minute bleeding site(s), which were then marked with a suture for histologic sectioning.

Pseudolymphoma of the stomach. A diagnostic and therapeutic dilemma.

Pseudolymphoma is an uncommon benign lesion of the stomach that poses a difficult problem in diagnosis and management. The clinical manifestations and endoscopic, radiologic, and biopsy findings are not generally helpful in making this diagnosis preoperatively. Histologic examination of the lesion is the only reliable method that distinguishes pseudolymphoma from true lymphoma.

Evaluation of biliary disease by scintigraphy.

The value of biliary scintigraphy was studied in 180 patients with suspected biliary tract disease. Scintigraphy was performed after intravenous injection of technetium-99m labelled (1) N-substituted iminodiacetic acid derivative (HIDA) in 91 patients, and (2) butyl derivative of iminodiacetic acid (BIDA) in 89 patients. Most of the patients were investigated additionally by conventional techniques such as cholecystography, cholangiography and ultrasonography.

Colonic tumorigenesis in rats with 1,2-dimethylhydrazine.

Subcutaneous injections of the carcinogen dimethylhydrazine in inbred Fischer 344 male rats induced squamous-cell carcinomas in the ear canal, adenocarcinomas in the small bowel and duodenum, and adenomas and adenocarcinomas in the large bowel. The incidences of the tumors induced in the large bowel and ear canal were dose-related. As for tumors of the large bowel, the average size of adenomas was less than that of adenocarcinomas with massive infiltration beyond the muscularis mucosa.

Incidence of ischemic colitis following abdominal aortic reconstruction.

The incidence of ischemic colitis following abdominal aortic reconstruction was determined by postoperative colonoscopy during a three year period. The over-all incidence of colitis was 11 of 163 patients who underwent elective or urgent reconstruction of the abdominal aorta for aneurysmal and occlusive diseases. The incidence of ischemic colitis for patients who survived resection of ruptured abdominal aortic aneurysms was higher, although the colonoscopy rate was lower.

Inferior mesenteric artery stump pressure: a reliable index for safe IMA ligation during abdominal aortic aneurysmectomy.

Fifty-two patients undergoing nonemergent abdominal aortic aneurysmectomy were prospectively studied to determine when the inferior mesenteric artery (IMA) could be ligated without subsequent development of ischemic colitis. Cannulation of the severed distal IMA for blood pressure measurement (IMA stump pressure) before and after aortic reconstruction was attempted in all and possible in 39 individuals. In 13 the IMA was thrombosed precluding pressure measurement.

Carcinoma of the prostate diagnosed initially as carcinoma of the rectum.

Carcinoma of the prostate appearing as a primary rectal tumor is more common than generally realized. Multiple biopsies with special stains and complete urologic investigation may be necessary before its prostatic origin can be established. The importance of making the proper diagnosis is underlined by the differences in treatment for the two lesions.

Arteriovenous malformations of the colon.

Arteriovenous malformations have become recognized as a major cause of massive bleeding of the colonic origin. Although an arteriographic unit capable of serial magnification is ideal for detecting arteriovenous malformations in the bowel, the diagnosis may still be made by a combined approach of conventional arteriography, colonoscopy and operative juddment. the final diagnosis rests on gross and histologic demostration of vascular malformations in the excised specimen.

Retrograde prolapse of the lleocecal valve.

Retrograde prolapse of the ileocecal valve results when redundant mucosa produces prominent lips of the ileocecal valve. The prominent valve produces a filling defect within the cecum. With manual palpation or hydrostatic pressure of the barium column, this prominent ileocecal valve then prolapses in a retrograde fashion to produce a tapered defect of the terminal ileum.

Spontaneous ischemic colitis.

Eighteen cases of spontaneous ischemic colitis are reviewed. The diagnosis was established according to the following criteria: 1) clinical background, 2) clinical characteristics, 3) morphologic characteristics, and 4) clinical and morphologic course. The last three constituted the diagnostic criteria.

Localization by immunoperoxidase and estimation by radioimmunoassay of carcinoembryonic antigen in colonic polyps.

A 3-layer immunoperoxidase technique was used to demonstrate carcinoembryonic antigen (CEA) in colonic polyps from patients with or without previous or concurrent malignancy. CEA was demonstrated in a higher percentage of the polyps received as fresh specimens that were rapidly frozen and fixed in ethanol, than in formalin-fixed, paraffin-embedded sections. Tissue CEA content of both colonic carcinomas and polyps was determined by radioimmunoassay, and it was found that benign colonic tumours had levels of tissue CEA comparable to colonic cancer, indicating that CEA concentration in a tumour does not reflect its grade of malignancy.

Carcinoma of anal-ductal origin: report of a case.

A 57-year-old man who had a carcinoma proven to be of anal ductal origin is presented. Recurrent perianal fistulas were treated locally for two years until biopsy proved the malignancy. Gross and histologic examination of the specimen removed by abdominoperineal resection demonstrated the anal ductal origin of this tumor.