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Biomedical subjects

R A Keenan

Publications and source records attributed to R A Keenan.

At least 19 recordsLinked to original sources
PubMed2002

Right hemicolectomy: mechanical bowel preparation is not required.

BACKGROUND: Mechanical bowel preparation before colonic surgery is widely advocated but remains controversial. Recent guidelines published by the Clinical Standards Board for Scotland recommend mechanical bowel preparation prior to surgery for all colorectal cancers but this may be inappropriate. This study examines the outcome of a policy of no mechanical preparation before elective right hemicolectomy. METHOD: Data on 102 consecutive patients undergoing elective right or extended right hemicolectomy for colonic adenocarcinoma were extracted from a prospective database. RESULTS: No clinical anastomotic leaks were observed. Two patients developed wound infections and one patient died with no autopsy evidence of anastomotic leak. CONCLUSION: Mechanical bowel preparation can safely be omitted prior to right hemicolectomy in patients with colonic cancer.

Adenocarcinoma↗
PubMed2001

Stromal tumour within a Meckel's diverticulum: CT and ultrasound findings.

The incidence of tumours within a Meckel's diverticulum is 0.5-3.2%. Their pre-operative diagnosis is rare. We report a case of an incidentally found gastrointestinal stromal tumour within a Meckel's diverticulum in a patient presenting with acute appendicitis. The tumour was demonstrated pre-operatively by ultrasound and CT.

Acute Disease↗
PubMed2001

Analysis of uracil DNA glycosylase in human colorectal cancer.

Uracil DNA glycosylase (UDG) is responsible for the removal of uracil present in DNA after cytosine deamination or misincorporation during replication. Colorectal cancer is widely treated with 5-FU, which leads to thymidylate synthase inhibition; this accounts for increased dUTP intracellular pools and subsequent uracil incorporation into DNA. Uracil misincorporation has also been implicated in the link between folate deficiency and colorectal cancer risk. As there is no information on UDG in colorectal cancer, this study characterized UDG activity and protein expression in a panel of 20 colorectal tumors and 6 colorectal cell lines. UDG activity in colorectal tissue is widely variable and it is statistically higher in tumor tissue (P=0.013) compared to normal bowel. Tumor versus normal activity ratios ranged from 0.49 to 2.2 (median 1.13). Among the six colorectal cell lines tested, UDG activity varied from 40 to 68 units and was markedly (1.7-fold) higher than in tumor tissue (P<0.0001). In both colorectal tissues and cell lines, UDG was expressed as both 29 kDa and 35 kDa forms. Total protein expression varied 3.2-fold in cell lines; variability was also found between patients and between normal and tumoral tissue for the same patient. This study demonstrates UDG protein and functional activity in human colorectal tumors and cell lines. The high tumor:normal tissue ratio supports further interest in base excision repair, through UDG, as a potential source of fluoropyrimidine resistance in colorectal cancer.

Aged↗
PubMed2001

Restorative proctocolectomy.

The development and refinement of pelvic pouch surgery now allows the excision of a diseased colon while maintaining transanal faecal continence. The success of restorative proctocolectomy is largely dependent on careful patient selection combined with meticulous surgical technique. The authors discuss the main indications for restorative proctocolectomy and describe the surgical procedure.

Humans↗
PubMed1999

Hydronephrosis: unrecognized complication following restorative proctocolectomy with ileal pouch-anal anastomosis.

Restorative proctocolectomy with ileal pouch-anal anastamosis (IPAA) is the operation of choice to avoid permanent ileostomy in the surgical management of patients with ulcerative colitis and familial adenomatous polyposis coli. IPAA with two loops of small intestine (J-pouch) is the most common configuration. Mortality rates are low, and despite significant morbidity patient satisfaction remains high. Functional results are good in most cases. We present two cases of hydronephrosis following IPAA. Loin pain was the presenting symptom in both cases, with one patient developing impaired renal function. Hydronephrosis has not been reported following IPAA, but with other forms of pelvic and retroperitoneal surgery it is believed to remain largely asymptomatic. We discuss the etiology of this previously unrecognized complication and suggest that it may be more prevalent following IPAA than is realized.

Abdominal Pain↗
PubMed1998

Characterization of dihydropyrimidine dehydrogenase in human colorectal tumours.

Dihydropyrimidine dehydrogenase (DPD) is the rate-limiting enzyme for degradation of 5-fluorouracil (5-FU). DPD activity is highly variable in liver and peripheral mononuclear cells (PMNCs) and it has not been well studied in human tumours. Characterization of DPD in colorectal cancer is of clinical interest through its role in the regulation of 5-FU, the main chemotherapeutic agent used in this disease. Therefore, DPD activity was analysed in colorectal tumour and adjacent normal tissue from 63 patients, including three liver metastasis. DPD activity was highly variable in all tissues studied (coefficient of variation 43-61%) and was higher in normal tissue than in tumour. The tumour-normal activity ratio ranged from 0.19 to 3.32 (median 0.76). PMNC DPD activity was available for 57 patients and was correlated with tumour activity (r(s) = 0.29, P < 0.001). A higher correlation was observed between PMNCs and tumour samples that were both obtained in the morning (r(s) = 0.49), consistent with circadian variation in DPD activity. Normal tissue DPD activity was not correlated with either tumour (r(s) = 0.11) or PMNC activity (r(s) = -0.06). This study provides the first analysis of DPD activity in colorectal cancer and illustrates the large degree of variation in tumour activity. The tumour-normal activity ratio results suggest that elevated tumour DPD can play a role in 5-FU resistance through increased inactivation in tumour cells, but is an uncommon event in colorectal tumours. The results support the use of PMNCs for monitoring tumour DPD activity, particularly when circadian variation is taken into account. As a large degree of the variation in tumour DPD activity is not explained by PMNC activity, more accurate alternatives are needed before DPD activity can be used for targeting 5-FU therapy.

Adult↗
PubMed1997

The impact of the development of restorative proctocolectomy on the management of inflammatory bowel disease in the north of Scotland.

In the North of Scotland, 40 out of 196 patients who had surgery for colitis between 1986 and 1992 underwent restorative proctocolectomy. The problems of the development of experience in a new technique were reduced by cooperation between two consultant surgeons from centres 100 miles apart who performed the first 30 operations together. Over 7 years, the standard operative technique evolved from perimuscular dissection of the rectum with formation of an S pouch and hand sutured endo-anal anastomosis to perimesenteric rectal dissection with a stapled J pouch and double stapled anastomosis. There was no mortality and no pelvic sepsis requiring urgent re-operation. One pouch has been removed subsequently because of Crohn's disease. One patient required revisional surgery for severe stricture of the ileo-anal anastomosis. At 1 year post-operatively, 35 out of 40 patients were highly satisfied with the result of surgery. The proportion of patients undergoing restorative proctocolectomy rather than panproctocolectomy for ulcerative colitis has risen from 15 to 52%. The number of total colectomies performed as initial procedures for colitis has increased. The age of patients who have restorative proctocolectomy has widened to include teenagers as well as a few patients over 50 years of age.

Adolescent↗
PubMed1997

Diverticular disease in patients under 50 years of age.

Sigmoid diverticular disease, when it occurs in a young age group, may follow a more aggressive course with a higher incidence of complications than in elderly. The mode of presentation and management in 77 patients under 50 years of age presenting with sigmoid diverticular disease over a 6-year period is described. Surgery for complications (peritonitis, abscess, bowel obstruction, fistula and haemorrhage) was performed in 18 (23%) individuals. Colonic resection was carried out in 14 (78%) of the operated group with primary anastomosis in six patients and Hartmann's procedure in eight patients. The mortality (30 day) was zero. Nineteen (25%) of the entire group, and 12 (67%) of those undergoing surgery had been previously hospitalized with a complication of diverticular disease. The recurrent nature and frequency of serious complications in this group, suggests that elective surgery should be considered if an acute infective episode is successfully managed conservatively.

Adult↗
PubMed1997

Vesico-colic fistulae in the Grampian region: presentation, assessment, management and outcome.

Over a 12-year period, 67 patients presented with a vesico-colic fistula. The mean age was 69 years (range 19-96 years), with symptoms predominantly referred to the urinary tract. Cystoscopy and barium enema confirmed the presence of a fistula in 60 and 44% of patients respectively. A computerized tomography (CT) scan, used in only seven patients, revealed the fistula in each case. The underlying pathology included diverticular disease (62%), carcinoma (27%) and inflammatory bowel disease (6%). Fifty-one patients proceeded to surgery, of whom 32 (63%) had a sigmoid/recto sigmoid resection with primary anastomosis, and 13 (25%) a Hartmann's procedure. A diverting colostomy alone was employed to palliate cases of widespread carcinoma. No patient subsequently had the Hartmann's reversed. In addition to colonic resection, 48 (92%) patients had a simultaneous bladder procedure, varying from simple oversew in 32 (70%) patients to cystectomy and ileal conduit in three (6%). Wedge excision with primary bladder closure was practised in 12 (24%). Fistula recurrence occurred in seven (14%) patients, and the 30-day mortality was 10%. Surgery for vesico-colic fistula has an appreciable morbidity and mortality, yet if offers the only hope of achieving permanent symptomatic control.

Adult↗
PubMed1996

Perianal Crohn's disease--is it all bad news?

PURPOSE: The outcome of treatment of perianal Crohn's disease was assessed in 127 patients. METHODS: A retrospective review of the case notes of 415 patients who were seen in the North East of Scotland between 1985 and 1989 was undertaken. RESULTS: A total of 127 of 415 patients with Crohn's disease had perianal involvement. In 56 patients, perianal disease was the presenting complaint. Ninety-nine of the 127 patients had colonic involvement. Thirty-two were treated with metronidazole and 41 were treated with azathioprine, with at least temporary improvement in 91 and 68 percent, respectively. Seventy patients had treatment for fistula-in-ano, and in 50 percent of patients permanent healing was achieved. In general, treatment and outcome were largely related to the extent and severity of gut involvement. Proctectomy was performed in 32 patients (in 11 because of ongoing colonic disease). Only seven patients had proctectomy solely because of perianal disease. Proctectomy was necessary in 32 of 99 patients with colitis and perianal disease but in none of 28 patients without colonic involvement. Primary healing of the perineal wound was obtained in 17 patients, and only one patient has an unhealed perineal wound at the time of reporting. CONCLUSION: Perianal Crohn's disease does not inevitably lead to panproctocolectomy. Cautious surgery for fistula when rectal inflammation is quiescent is worthwhile. Loss of bowel continuity is more likely when colitis coexists with perianal disease. Panproctocolectomy is often indicated because of the combination of colitis and perianal disease rather than for perianal disease alone.

Adolescent↗
PubMed1996

Gastric lymphoma in Grampian Region: presentation, treatment and outcome.

Forty cases of gastric lymphoma presenting in Grampian Region (1974-91) were reviewed to examine the effects of changing ideas in the fields of chemotherapy, gastric surgery and diagnostic techniques, as well as the impact of Helicobacter pylori. Presentation was non-specific, and the diagnosis was made pre-operatively in only 12 cases. Survival was related to tumour size, staging (Ann Arbor), and grade, with a crude 5-year survival of 49%. Helicobacter pylori was found in all specimens reviewed. Patients who underwent "potentially curative' surgery followed by adjuvant therapy had the best survival (85% at 5 years). There remains a need for larger studies to define the best treatment for this uncommon condition.

Adult↗
PubMed1996

Massive intestinal bleeding in association with Crohn's disease.

Five hundred and one patients with Crohn's disease, presenting to a single surgical unit during a 20-year period, were reviewed by utilizing a computerized audit system. Ten patients were identified with rectal bleeding significant enough to require a blood transfusion to maintain cardiovascular homeostasis. The site of bleeding was correctly identified pre-operatively in only one patient, and at the time of surgery in only four patients. In nine (90%) of the 10 cases, the origin of the bleeding was subsequently found to be colonic. All 10 patients were treated surgically, with seven patients requiring fashioning of a stoma, none of whom had gastro-intestinal continuity subsequently re-established. Recurrent bleeding occurred in a single patient. The early post-operative mortality was 20%. Massive rectal bleeding remains an uncommon complication of Crohn's disease, and still carries significant morbidity and mortality. Pre-operative localization of the site of bleeding is uncommon, making intra-operative identification of the bleeding area difficult.

Adult↗
PubMed1995

Colectomy for acute colitis: is it safe to close the rectal stump?

We report 62 operations for acute colonic inflammatory bowel disease in which the rectal stump was closed. Operative findings were of severe colitis in 46, toxic megacolon in 8 and faecal peritonitis in 8 patients. Histology showed ulcerative colitis in 48, Crohn's disease in 9 and indeterminate colitis in 5 patients. Clinical evidence of stump leakage occurred in only one of 53 patients with a long rectal stump in contrast to 3 of 9 patients who had a short rectal stump. Leaving a very short stump also led to difficulty at subsequent proctectomy in 3 patients and at restorative proctocolectomy in 1 patient. This suggests that careful closure of the rectum above the peritoneal reflection can be a safe means of dealing with the rectal stump after total colectomy and ileostomy for acute colitis.

Acute Disease↗
PubMed1994

Loop ileostomy fixation: a simple technique to minimise the risk of stomal volvulus.

Turnbull's "loop" ileostomies is a routinely performed procedure in the management of a variety of colorectal problems. Mechanical and functional complications occur with both permanent and temporary ileostomies, however they are more common with the loop than with the end (Brooke) variety. With the advent of restorative proctocolectomy with pouch formation, and the documented benefit of simultaneous temporary faecal diversion, the incidence of such complications will rise. Bowel obstruction, requiring laparotomy in the interval before stoma closure, is more commonly associated with the loop ileostomy. A loop stoma is routinely brought out directly through the abdominal wall, with little or no fixation or closure of the lateral space. However, anti-mesenteric fixation, as described here, minimises the risk of volvulus by widening the attachment of the adjacent ileum to the parities, creating a broader fulcrum. Since adopting this simple technique, we report no complications in over 30 loop ileostomies, "fixed" by this technique and followed up for a minimum of 4 years. Where applicable, no difficulty was encountered with stoma closure, either by a transverse single layer serosubmucosal technique, or as a minimal resection with end to end anastomosis (sewn or stapled), following bowel mobilisation. This technique should minimise the frequency of obstructive events, and we recommend it's routine use.

Adolescent↗
PubMed1994

Mucosal changes in the large bowel with endometriosis: a possible cause of misdiagnosis of colitis?

Endometriotic deposits are not uncommon in the large bowel of women. Because the symptoms produced by endometriosis may lead to investigation by colorectal endoscopic biopsy, the aims of this study were to assess the range of mucosal abnormalities that may occur and to determine whether this could represent a significant potential diagnostic problem. We found mucosal changes in eight of 10 cases of colorectal endometriosis; however, the abnormalities (ulceration, gland architectural disturbance, crypt abscess formation, increased inflammatory cell presence, and smooth muscle fibers between glands in the mucosa) were focal and directly related to endometrial deposits. In one case an abnormal colonic biopsy specimen from a patient with endometriosis supported the erroneous clinical diagnosis of Crohn's disease. Comparing a group of women with endometriosis to a group with adenomyosis of the uterus showed that although more women with endometriosis have endoscopic large bowel biopsies, there was no significant excess of biopsy specimens showing inflammatory changes. Our conclusion is that the endometriosis of the large bowel can masquerade as inflammatory bowel disease or ischemic changes and the possibility should be borne in mind, particularly in cases with atypical clinical features or very focal histological changes.

Adult↗
PubMed1992

Management of the rectum following colectomy for acute colitis.

During a 6 year period, 31 consecutive patients under the care of one surgeon had emergency colectomies for complicated colitis. A selective policy of closing the rectum intraperitoneally to minimize the length of retained diseased bowel and to avoid a mucus fistula was used during the study period. One patient underwent proctocolectomy, 7 subtotal colectomy with mucus fistula and 23 total colectomies with intraperitoneal closure of the rectum. Two patients (8.9%) developed pelvic sepsis. Both had intraperitoneal closure of the rectal stump and were readily managed by drainage into the stump. Subsequent surgery in the 18 patients having rectal excision has been uncomplicated. Intraperitoneal closure of the rectal stump in emergency surgery for complicated colitis can be performed safely in most of these patients.

Acute Disease↗