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Biomedical subjects

J L McCue

Publications and source records attributed to J L McCue.

8 recordsLinked to original sources
PubMed1995

Adjuvant radiotherapy and anastomosis in rectal cancer--disturbing evidence from animal studies.

PURPOSE: Adjuvant radiotherapy is used increasingly in the management of rectal cancer. However, ionizing radiation is mutagenic, and, superimposed on a background of increased cellular proliferation as seen around anastomoses and in colorectal cancer patients, there is the potential for enhanced metachronous cancer risk. METHOD: The influence of preoperative irradiation on both carcinogenesis and cellular proliferation at colonic anastomoses was explored in 180 adult male F344 rats. Orthovoltage x-rays were delivered to the distal descending colon by parallel opposed fields. Ninety rats received 16 Gy in one fraction; the remainder received 36 Gy in two fractions one week apart. In each irradiation group 18 rats either acted as controls or one week after radiotherapy underwent distal colotomy and repair. RESULTS: We found the descending colon susceptible to radiation carcinogenesis; 26 colorectal tumors developed in the low-dose irradiation group and 47 in the high-dose group (P = 0.0008; Mann-Whitney U test, 16 vs. 36 Gy). Preferential tumor development was seen in the anastomotic region. In those animals that underwent surgery and irradiation, among the low-dose irradiation group only 3 of 72 had tumors within the descending colon compared with 21 of 72 at the anastomotic site (McNemar's test chi-squared = 40.9; P < 0.001), and in the high-dose irradiation group 5 of 72 had tumors within the descending colon compared with 36 of 72 at the anastomotic site (McNemar's test chi-squared = 22.0; P < 0.001). Anastomotic crypt cell production rates were increased for at least three months following exposure to irradiation (16 Gy: f = 15.1, P < 0.005; 32 Gy: f = 9.4, P < 0.005). CONCLUSIONS: Radiation carcinogenesis is greatly enhanced at colonic anastomoses and may result from altered anastomotic proliferation. This has potentially disturbing implications in view of the increasing use of adjuvant radiotherapy for rectal carcinoma.

Adenocarcinoma↗
PubMed1993

Cellular proliferation at sutured and sutureless colonic anastomoses.

Elevated cellular proliferation in the vicinity of an anastomosis may explain the enhanced susceptibility to carcinogens. The aim of this study was to determine whether anastomotic cellular proliferation was altered by different suture materials and whether a rise in cell turnover also occurred after a "sutureless" closure. A transverse descending colon enterotomy was repaired with interrupted sutures of 5/0 silk (n = 20), stainless steel (n = 20), or Vicryl (Ethicon, Inc., Somerville, NJ) (n = 20) or by a sutureless technique (n = 20). Using a stathmokinetic technique, crypt cell production rates (CCPR) were calculated at the anastomosis and in the adjacent colon at varying intervals between one week and six months after treatment. Overall colonic cellular proliferation appeared to be elevated at a sutured colotomy for at least three months (P < 0.05). In contrast, no significant elevation in cellular proliferation was observed at sutureless anastomoses. The duration of elevated proliferative response varied among the sutures.

Anastomosis, Surgical↗
PubMed1992

Experimental carcinogenesis at sutured and sutureless colonic anastomoses.

This study explores the role of sutures and the healing colonic wound in experimental carcinogenesis. One hundred sixty rats underwent surgery with colotomy and repair using silk, steel, or Vicryl (Ethicon, Somerville, NJ) sutures or a sutureless technique. Forty rats had a sham procedure. All animals received azoxymethane for 12 weeks at a dose of 10 mg/kg/week. Half the rats commenced carcinogen before surgery, and half commenced it eight weeks after surgery. Animals with anastomotic tumors were found in 46 percent of the sham group (P less than 0.05 cf. sutured), 41 percent of the sutureless group (P less than 0.02 cf. sutured), and 68 percent of the sutured group. The corresponding figures for anastomotic carcinoma were 9 percent (P less than 0.001 cf. sutured), 22 percent, and 38 percent. No significant differences in tumor yield were noted among the different sutures. However, several differences were noted between the two carcinogen models. In those animals that received surgery first, there was a higher incidence of anastomotic tumors (P less than 0.002) and cancers (P less than 0.0001) in the sutured and sutureless groups, and those tumors that occurred in the sutured group were considerably larger than in those that had carcinogen first (15.9 mm cf. 4.9 mm; P less than 0.0001). Overall, all sutures seem to enhance anastomotic tumor formation, and we would suggest that a sutureless anastomosis may diminish this risk.

Anastomosis, Surgical↗
PubMed1991

Clinical and functional results of abdominal rectopexy for complete rectal prolapse.

Between 1977 and 1987, 53 patients underwent polyvinyl alcohol sponge rectopexy for complete rectal prolapse. The mean follow-up period was 36.7 months. Full thickness prolapse recurred in two patients (3.8 per cent). Infection around the prosthesis and faecal impaction developed in two patients each. Continence improved significantly after operation, particularly in those under 70 years of age (P = 0.028, chi 2 test) and nulliparous women (P = 0.026, chi 2 test). Bowel function was generally unchanged after rectopexy; in particular only eight patients (15 per cent) had significant postoperative constipation.

Adolescent↗
PubMed1991

Sutureless intestinal anastomoses.

Sutureless intestinal anastomoses can be achieved either by compression, where two inverted rings of bowel are compressed by a hollow circular device that subsequently sloughs away and is passed anally, or by the use of tissue glues or laser welding. Compression devices used clinically with success are the Valtrac biofragmentable anastomotic ring, the polypropylene rings described by Rosati and the AKA guns. Glued anastomoses have only been used in animals and seem to be unsafe. However, laser-welded intestinal anastomoses appear highly promising in experimental studies and further development of this technique is warranted.

Adhesives↗
PubMed1990

Rectopexy for internal rectal intussusception.

Twelve patients presented with symptomatic internal intussusception of the rectum between 1979 and 1987. All were women with a mean age of 55.5 years. Ten patients had symptoms of obstructed defaecation and only three were completely continent. Polyvinyl alcohol sponge abdominal rectopexy was performed in each patient. Over a mean follow-up period of 26.9 months there was no recurrence of internal intussusception. The functional results, however, were mixed but only one patient remained incontinent for solid stool. Rectal discomfort and defaecatory difficulties persisted; six patients continued to strain at stool and in three this was worsened by the operation. Abdominal rectopexy can be recommended for those with associated incontinence, significant rectal bleeding or solitary rectal ulcer but may not benefit those who have obstructed defaecation.

Fecal Incontinence↗