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Biomedical subjects

S T McKelvey

Publications and source records attributed to S T McKelvey.

At least 19 recordsLinked to original sources

Bile acids and the increased risk of colorectal tumours after truncal vagotomy.

An association between colorectal cancer and previous peptic ulcer surgery is reported. In a prospective screening study, 100 asymptomatic patients (80 men and 20 women) who had undergone truncal vagotomy at least 10 years previously were investigated by barium enema, colonoscopy and gallbladder ultrasonography. Control data were obtained from forensic autopsy subjects. The incidence of neoplasms greater than or equal to 1.0 cm in the vagotomized group was 14 per cent (11 adenomas, 3 carcinomas) and 3 per cent in controls (P = 0.01). Duodenal bile obtained at endoscopy from 21 vagotomized patients with normal gallbladders and from 21 control patients undergoing endoscopy was analysed by high performance liquid chromatography. The mean percentage of cholic (CA), chenodeoxycholic (CDCA), deoxycholic (DCA) and lithocholic (LCA) acids in the bile of vagotomized patients was 32.3, 45.6, 20.7 and 1.4 per cent respectively compared with 45.3, 36.2, 17.9 and 0.7 per cent respectively in controls. The increased proportions of CDCA and LCA and decreased proportions of CA in the duodenal bile of vagotomized patients were significant (P less than 0.001; P = 0.02; P = 0.007). Abnormalities in bile acid metabolism may help to explain the increased risk of colorectal neoplasia 10 years after truncal vagotomy.

Bile Acids and Salts↗

Wound sepsis in 10,000 surgical patients.

A twelve year prospective wound audit was undertaken in an academic surgical unit. Data from 10,000 operations were analysed. Overall, wound infection rates decreased during this time. Infection rates in contaminated wounds in particular fell from 19.2% to 4.7%. This decrease in wound infection may be related in part to a change in the antibiotic prophylactic regimen and in part to the institution of the wound sepsis audit which provided regular information on the unit infection rates. This audit permitted early detection of adverse trends, and may have had a direct influence on surgical techniques.

Cephalosporins↗

Cholecystectomy and the development of colorectal neoplasia: a prospective study.

One hundred asymptomatic patients over 60 years of age who had cholecystectomy carried out at least 10 years earlier underwent double contrast barium enema and sigmoidoscopy. The incidence of colorectal adenomas and carcinomas was compared with age and sex matched controls undergoing routine post mortems. In the post-cholecystectomy group 12% had tumours (8 adenomas greater than 1 cm in diameter, 4 carcinomas). In the control group 3% had tumours (3 adenomas); P = 0.02. This study confirms that patients with a history of cholecystectomy have an increased risk of developing colorectal adenomas and carcinomas.

Adenoma↗

Assessment of ornithine decarboxylase activity in rectal mucosa as a marker for colorectal adenomas and carcinomas.

We have investigated the role of ornithine decarboxylase activity in rectal mucosa as a marker for colorectal neoplasia. Biopsies of normal rectal mucosa were taken from 18 patients with adenomas greater than 1 cm diameter, 11 with carcinomas and 16 controls. The mean ornithine decarboxylase activity in normal rectal mucosa of adenoma patients, 6.52 nmol CO2 released h-1 (mg cell protein)-1, was significantly lower than that in controls, 16.8, P = 0.006. The difference in rectal ornithine decarboxylase activities between cancer patients, 3.58, and controls was also significant, P = 0.001. These preliminary results suggest that ornithine decarboxylase may be a useful marker in screening for colorectal neoplasia.

Adenocarcinoma↗

Relationship between duodenal bile acids and colorectal neoplasia.

To investigate a possible relationship between bile acids and colorectal neoplasia duodenal bile acids were analysed in 50 patients with colorectal adenomas and 14 with carcinoma. Using gas liquid and high performance liquid chromatography a small, but significant increase in the proportion of chenodeoxycholic acid was found in the bile of adenoma patients compared with controls (mean % +/- SD 31.0 +/- 10.8, 26.4 +/- 8.3, p = 0.01). The difference in the proportions of chenodeoxycholic acid correlated with increasing malignant potential of the adenomas as determined by increasing size, histological type, degree of dysplasia and number present. In carcinoma patients an increase in the proportion of chenodeoxycholic acid was also observed compared with controls (mean % +/- SD, 47.2 +/- 9.6, 28.0 +/- 4.5, p less than 0.01). The proportions of other bile acids in those with adenoma or carcinoma were normal.

Adenoma↗

Auditing perioperative mortality.

An audit of mortality following operation was performed over ten years classifying deaths into those that were 'expected' and 'unexpected'. 'Unexpected' deaths were defined as those in which, after careful consideration of the prevailing clinical circumstances at the time of operation, the probability of death following operation was felt to be low. This definition is a more helpful assessment of surgical performance than overall perioperative mortality as it highlights cases where improvements in surgical management might be achieved. In audits involving surgical mortality, the classification of deaths into 'expected' and 'unexpected' is recommended.

Hospitalization↗

Does cholecystectomy predispose to colorectal cancer? A case control study.

A case-control study of 598 patients with colorectal cancer (296 men, 302 women) admitted from January 1974 to October 1983 was undertaken. Patients were matched for age and sex, with controls admitted for unrelated conditions. All information was obtained from the hospital records. In men, there was no evidence of an increased risk of colonic cancer after cholecystectomy relative to men without cholecystectomy. There was some evidence of an increased risk in women (relative risk = 1.7; 95 percent confidence interval, 1.0 to 3.1) and this was highest when the tumor was in the right colon (P less than 0.005). This study confirms previous observations that cholecystectomy leads to an increased risk of right-sided colonic tumors in women but not in men. The apparent difference between the sexes may be explained by the low rate of cholecystectomy in the men examined.

Cholecystectomy↗

Low colorectal anastomoses. An experimental assessment of two sutured and two stapled techniques.

Extraperitoneal colorectal anastomoses were constructed in dogs by four methods: one layer of sutures (N = 10), two layers of sutures (N = 10), EEA staples (N = 10), and SPTU staples (N = 10). Dehiscence occurred in eight sutured and one stapled anastomosis (P less than 0.05). The four leaks following two layer sutured anastomoses caused three deaths, whereas all four leaks following one-layer sutured anastomoses were only detected radiologically (P less than 0.02). In the stapled group, the single leak followed EEA anastomosis and was fatal. Anastomotic narrowing was greater in sutured than stapled groups (P less than 0.05). Two layers of sutures produced gross narrowing compared with one layer (P less than 0.002). Two rows of staples (EEA) produced more narrowing than one row (SPTU) (P less than 0.01). Mean hydroxyproline concentrations and bursting pressures on the seventh postoperative day were higher in stapled than sutured anastomoses (P less than 0.05). Submucosal alignment, mucosal continuity, tissue viability, and stage of healing were all inferior for two-layer sutured anastomoses, reaching statistical significance for tissue viability (P less than 0.05). Stapled anastomoses were completed significantly faster (32.6 +/- 7.3 minutes) than sutured (54.1 +/- 8.4 minutes) (P less than 0.01). This experimental study has demonstrated that stapling is a fast and reliable method of colorectal anastomosis with a low complication rate. The shortcomings of the standard two-layer sutured anastomosis are discussed.

Animals↗

The pelvic ileal reservoir. An experimental comparison of the 3-loop and 2-loop systems.

In an experimental study the function of the 3-loop (Parks) pelvic ileal reservoir was compared with that of the 2-loop (Utsunomiya) reservoir. Both types achieved satisfactory degrees of continence and evacuation when tested in the defunctioned state. Following restoration of intestinal continuity, the stools of dogs with 3-loop pouches were usually liquid (69 percent) compared to the more formed stools (72 percent) in the 2-loop group, P less than 0.001. At postmortem the reservoirs of the 3-loop group were found to have undergone much greater dilatation (P less than 0.05). These findings suggest that construction of the 3-loop (Parks) pelvic reservoir may lead to retention with overflow if catheterization is not used. It is not clear whether the superior function of the 2-loop pouch is attributable to better motor function or the absence of an efferent limb which allows it to be placed deep in the pelvis.

Animals↗

A controlled trial of bipolar electrocoagulation in patients with upper gastrointestinal bleeding.

We have assessed the value of the BICAP electrocoagulation probe in reducing the incidence of further bleeding in patients with upper gastrointestinal haemorrhage. One hundred and twenty-nine patients were studied in a prospective randomized controlled trial. There were 85 male and 44 female patients, age range 16-92 years. Forty-five patients had stigmata of recent haemorrhage (visible vessel or spot) and were randomized during endoscopy to 24 control and 21 treatment patients. Seven control patients rebled compared with nine treated patients (Fisher's exact probability test P = 0.44). The transfusion requirements of control patients (3.9 +/- 3.2 units) was not different from that of treated patients (5.7 +/- 3.7 units): Mann Whitney U test, P = 0.06. In the treatment group there was no difference in the operation rate. Also, the number of probe applications between patients with further bleeding and those with no further bleeding was similar (11.6 +/- 5.5 and 11.0 +/- 5.75 respectively). Access with the probe was considered inadequate in 50 per cent of lesions, but this did not correlate with the incidence of rebleeding. Stigmata of recent haemorrhage were significant in predicting rebleeding (P = 0.0019 Fisher's exact probability test). Overall mortality rate of 3.2 per cent was low and was not influenced by electrocoagulation or presence of stigmata of recent haemorrhage. We have not shown that BICAP bipolar electrocoagulation reduces the incidence of rebleeding in upper gastrointestinal haemorrhage.

Adult↗

Ileal reservoirs: an experimental study of motility in the Kock and triplicated pelvic ileal pouches.

Motor activity in the Kock ileostomy reservoir and the triplicated pelvic ileal reservoir was studied experimentally in dogs and compared with normal terminal ileum under identical conditions. Despite claims to the contrary, both reservoirs possessed significant motor activity under basal conditions and on filling. This was reduced, however, compared with normal terminal ileum. The design of the Kock reservoir does not seem to have any distinct advantages over the triplicated ileal reservoir which may be used either as an abdominal or pelvic pouch.

Animals↗