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Biomedical subjects

R E Condon

Publications and source records attributed to R E Condon.

At least 19 recordsLinked to original sources
PubMed1992

Arginine vasopressin inhibits phasic contractions and stimulates giant contractions in monkey colon.

Abdominal cramps and urgent defecation are common side effects of clinical doses of arginine vasopressin, indicating that the drug may have stimulating effects on colonic motor activity. Four strain-gauge transducers were implanted on the colon in six monkeys. A blood flow probe was fixed on the inferior mesenteric artery. After a 1-hour control recording, vasopressin, 0.13, 1.3, or 13.0 ng.kg-1.min-1, was infused intravenously for 90 minutes. The frequency of basal colonic contractions was reduced with increasing doses of vasopressin, but their mean amplitude and duration were not altered. Giant migrating contractions associated with defecation were initiated by the highest dose of vasopressin. Atropine had no effect on these giant migrating contractions but completely inhibited normal phasic contractions. Hexamethonium completely inhibited both giant migrating contractions and phasic contractions. Parasympathetic denervation of the colon did not inhibit giant migrating contractions initiated by vasopressin. Our findings suggest that the physiological concentrations of serum vasopressin present perioperatively may transiently inhibit spontaneous colon contractions but are unlikely to be the major cause of postoperative ileus. The giant migrating contractions initiated by vasopressin may account for the defecation associated with pharmacological doses of vasopressin. The initiation of giant migrating contractions by vasopressin may be mediated through a neural pathway.

Animals↗
PubMed1992

Selective adrenergic agonists and colon motility in monkeys.

Sympathetic stimulation during and after laparotomy and other surgical procedures may be a factor inducing postoperative ileus. In experiments conducted in fasting monkeys, the effects of the selective sympathetic agonists alpha 1 (phenylephrine), alpha 2 (ST-91), beta 1 (dobutamine), and beta 2 (terbutaline) on colon contractile activity were measured. Strain gauges were implanted on the colon. Recordings were made for 1 hour (control) and then for an additional hour during continuous infusion by one of a range of doses of each drug (experimental). The drug doses were chosen to cover both physiologic and pharmacologic concentrations. All of the sympathetic agonists caused a dose-dependent decrease in the frequency of colon contractions. The beta-agonists did so at a concentration that is sufficiently low to support a hypothesis that beta-stimulation leading to inhibition of smooth-muscle contraction may play an important role in the genesis of postoperative ileus.

Adrenergic alpha-Agonists↗
PubMed1992

Antibiotic prophylaxis for scheduled operative procedures.

As a result of numerous trials during the past two decades addressing antibiotic prophylaxis for surgical procedures, it has been established that appropriately administered antibiotic prophylaxis reduces the risk of postoperative infection by about 50% when compared with comparable untreated patients. Antibiotics cannot completely eliminate all risk of infection, however, and will never be a substitute for good surgical practices.

Anti-Bacterial Agents↗
PubMed1979

Effective surgical therapy of esophagitis. Experience with Belsey, Hill, and Nissen operations.

During the years 1971 to 1978, 252 patients needed surgical treatment of primary or secondary esophagitis. Major operations performed were 73 Belsey Mark IV repairs, 55 Hill repairs, and 129 Nissen repairs. In the group with primary reflux, barium swallow tests and endoscopy were useful in confirming the diagnosis in patients with typical symptoms; routine biopsy, lower esophageal sphincter, manometry or an acid infusion test did not add to diagnostic certitude. If symptoms were atypical, a biopsy was helpful but manometry and acid infusion were not. Mean symptom scores in this group of patients were improved by each of the "valve-building" operations. Intraoperative dilation after mobilization of the esophagus coupled with a valve-building operation was successful in managing 26 of 29 strictures. Reoperation after an operation failed carried appreciable morbidity and mortality but resulted in good control of symptoms. Addition of a Belsey or Nissen procedure to myotomy for management of primary esophageal motility disorders diminished symptoms and did not cause disabling obstruction.

Collagen Diseases↗
PubMed1979

Preoperative prophylactic cephalothin fails to control septic complications of colorectal operations: results of controlled clinical trial. A Veterans Administration cooperative study.

Data obtained from a survey of the membership of the Society for Surgery of the Alimentary Tract and the American Society of Colon and Rectal Surgeons indicated that concomitant administration of oral neomycin-erythromycin base and systemic cephalothin, together with mechanical colon cleansing, was the most popular method of colon preparation. We designed a prospective double blind clinical trial to compare administration of intravenous cephalothin, oral neomycin-erythromycin base, and the combination of both the intravenous and oral antibiotics. Intake of patients to the intravenous cephalothin group was stopped because the data indicated that this method of prophylaxis resulted in significantly higher numbers of septic complications. The incidence of wound infection was 30 per cent and the overall incidence of septic complications was 39 per cent in patients receiving only intravenous cephalothin combined with mechanical colon cleansing. The incidence of wound infection and the overall incidence of septic complications was only 6 per cent in the comparison group, and the differences are highly significant.

Aminoglycosides↗
PubMed1979

Electromotor feeding responses of primate ileum and colon.

Serosal bipolar electrodes to record spike discharges and strain gauge force transducers to record circular muscle contractions were placed in pairs on the terminal ileum, cecum, right colon at the ileocecal valve, ascending colon, and proximal transverse colon of sixteen primates. After an overnight fast, electromotor responses to continued fasting or to ingestion of a meal (randomized order) were recorded in awake animals. Feeding led to increased spike discharges and increased frequency of muscle contractions at all sites. The onset of these responses usually was within 6 minutes after feeding; the responses increased progressively during 30 to 45 minutes and then remained more or less at a constant plateau of increased activity. Atropine completely blocked the postcibal responses of ileum and proximal colon for up to 30 minutes. Transit time data of labeled meals excluded direct stimulation by a food bolus as the mechanism of the observed postcibal colonic response. The pattern of response was consistent with humoral mediation.

Animals↗
PubMed1979

Effect of dietary fiber on intraluminal pressure and myoelectrical activity of left colon in monkeys.

The effects of varying intake of dietary fiber content on left colon intraluminal pressure, electrical spike discharge activity, and contractions of circular muscle were measured in stump-tailed monkeys. Animals were preconditioned to sit in restraint chairs and then had the sigmoid colon instrumented with an extraluminal strain gage force transducer, a bipolar serosal electrode and a Thomas cannula to provide access for determining luminal pressure with a perfused, open-tip catheter. Diets containing 0, 5, 10, 15, and 20 g of dietary fiber daily were fed in varying sequences for periods of 3 wk. Observations were made twice during the last week of each diet. Fecal weight increased in animals on a high fiber diet, but changing dietary fiber content did not alter the duration of spike discharge activity and produced only a minimal change in the contraciton frequency of colon circular muscle. Colon intraluminal pressure was increased significantly by feeding low-fiber diets, but intraluminal pressure responses did not always correlate with the myoelectrical activity of the colon circular muscle.

Animals↗
PubMed1978

Diarrhea and colitis in clindamycin-treated surgical patients.

Responding to reports that diarrhea and pseudomenbranous colitis occurred relatively frequently among patients who received clindamycin, we initiated a program of surveillance in clindamycin-treated patients, including direct examination of the colon mucosa for inflammation or pseudomembranes and a patient follow-up by a nurse-epidemiologist. Observation of 145 patients having 161 consecutive clindamycin treatment episodes determined that unexplained diarrhea (two or more stools per day) occurred in 30 patients (21%), and more severe diarrhea (five or more stools per day) occurred in 12 patients (8%). Colitis was not identified at all. The absence of pseudomembranes was confirmed by direct examination of colon mucosa in 114 patients. Development of disabling diarrhea or colitis in association with clindamycin therapy is not a universal phenomenon.

Adolescent↗
PubMed1978

A quarter Wheatstone bridge strain gage force transducer for recording gut motility.

Quarter and half Wheatstone bridge extraluminal force transducers for recording of gastrointestinal motility are compared. Modification of the transducer to a quarter bridge is economical, simplifies construction, and improves longevity by eliminating the crossover wire which frequently short circuits. The quarter bridge transducer was found to be as accurate and sensitive as the half bridge transducer.

Animals↗
PubMed1978

Veterans Administration Cooperative Study on Bowel Preparation for Elective Colorectal Operations: impact of oral antibiotic regimen on colonic flora, wound irrigation cultures and bacteriology of septic complications.

A ten hospital cooperative study comparing prophylactic oral neomycin and erythromycin base versus placebo demonstrated clinical efficacy of the antibiotics in preventing septic complications following elective colon operations. The present report concerns microbiological studies accomplished during this trial. Cultures of colon contents during surgery showed the antibiotic prep reduced concentrations of both aerobes and anaerobes by approximately 10(5) bacteria/ml. Virtually all major bacterial components of the normal flora were affected. Wound irrigation specimens at the time of closure failed to predict subsequent wound infection, but significantly fewer antibiotic recipients had positive irrigation cultures. Postoperative stool specimens showed that the oral antibiotics did not cause an emergence in resistant forms. Bacteriological studies of postoperative infections indicated that most postoperative infections involved a mixed aerobic-anaerobic flora, and that Bacteroides fragilis accounted for six of eight episodes of bacteremia.

Bacteria↗
PubMed1978

Postoperative ileus: a colonic problem?

Postoperative electromechanical activity of the gastric antrum, small bowel, right colon, and sigmoid colon was recorded in stumptail monkeys in response to retroperitoneal dissection and transient clamping of the renal pedicle. Bipolar silver electrodes and extraluminal bonded strain gauge transducers were used to record slow-wave and spike discharges and contractions of intestinal smooth muscle. After operation myoelectric activity was decreased transiently in the antrum and for only a few hours in the small bowel. Right colon contractile activity was decreased significantly for 24 hours and that of the sigmoid colon for 72 hours. Postoperative inhibition of bowel motility appears to be most profound and persistent in the colon.

Abdomen↗
PubMed1977

Familial polyposis.

Familial polyposis is a genetically-transmitted disease characterized by multiple adenomatous colorectal polyps and a high risk for development of adenocarcinoma. Familial polyposis and Gardner's syndrome should be differentiated from other penetically-linked polyposis syndromes lacking a predisposition for cancer. Total colectomy and ileorectal anastomosis, aggressive follow-up and intensive surveillance of non-polyp bearing relatives can reduce the risk of developing cancer. From an epidemiologic point of veiw, polyposis is a valuable model for the study of the interaction of genetic and environmental factors in the genesis of colon cancer.

Adult↗
PubMed1977

Surgical and medical measures in prevention of large bowel cancer.

Traditional methods for prevention of large bowel cancer rely on surveillance of patients with known precursors of bowel cancer, namely ulcerative colitis and those genetically linked polyposis syndromes that have malignant potential. Identification of heritable bowel cancer families and solitary polyp--cancer families provide additional populations that merit intensive scrutiny. Persuasive, if circumstantial, evidence suggests that maintaining patients free of large bowel polyps reduces the risk of developing large bowel cancer. Prospects for prevention of large bowel cancer are extended by recognition that a diet low in fat may reduce the risk of large bowel cancer. Furthermore, there is considerable evidence in animals that a variety of antioxidants limit large bowel carcinogenesis and preliminary evidence in man that these agents may control large bowel neoplasia.

Adenoma↗
PubMed1977

Preoperative oral antibiotics reduce septic complications of colon operations: results of prospective, randomized, double-blind clinical study.

The effectiveness of short-term, low-dose, preoperative oral administration of neomycin and erythromycin base combined with vigorous purgation in reducing the incidence of wound infections and other septic complications of elective colon and rectal operations has been studied in a prospective, randomized, double-blind, clinical trial. One hundred and sixteen patients completed the study; all received mechanical preparation; 56 received neomycin-erythromycin base while 60 received an identical appearing placebo. The two patient groups were comparable in age distribution, clinical diagnoses, associated systemic diseases, types of operation performed and similar clinical features. The overall rate of directly related septic complications was 43 per cent in the placebo group and 9% in the group receiving neomycin and erythromycin base. The wound infection rates were 35% in placebo and 9% in antibiotic treated patients. Oral administration of neomycin and erythromycin base together with vigorous mechanical cleansing reduces the risk of septic complications after elective colo-rectal operations.

Abscess↗