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Biomedical subjects

R S McLeod

Publications and source records attributed to R S McLeod.

At least 19 recordsLinked to original sources
PubMed2006

Increased experience and surgical technique lead to improved outcome after ileal pouch-anal anastomosis: a population-based study.

PURPOSE: This study was designed to determine whether changes in length of stay and 30-day readmission, reoperation, and excision rates for the ileal pouch-anal anastomosis occurred over time and with changes in surgical technique and hospital volume. METHODS: Using three population-based administrative databases, data on all ileal pouch-anal anastomoses performed in the province of Ontario between January 1992 and June 1998 were obtained. The effect of age, gender, stage of the procedure, year of surgery, and hospital volume were examined for their effect on length of stay and readmission, reoperation, and excision rates. RESULTS: There were 1,285 ileal pouch-anal anastomoses performed in 58 hospitals. There was a significant decrease in length of stay and reoperation and excision rates but a concommitant increase in readmission rate during the study period. Patients younger than aged 40 years had a significantly lower length of stay and excision rate. Patients who had a two-stage procedure had a shorter length of stay, readmission, and reoperative rate compared with those having a three-stage procedure. Hospital volume was a significant predictor of need for reoperation and excision with both low-volume and medium-volume hospitals having significantly higher rates than high-volume hospitals. CONCLUSIONS: Outcome after ileal pouch-anal anastomosis has improved. It is significantly better in patients younger than aged 40 years, having a two-stage procedure, and where surgery is performed at high-volume hospitals. It is likely that both modifications in surgical technique and surgical experience have led to improvements in clinical outcome after ileal pouch-anal anastomosis.

Adult↗
PubMed2004

Nonsteroidal anti-inflammatory drugs and aspirin for the prevention of colorectal adenomas and cancer: a systematic review.

PURPOSE: A systematic review was conducted to determine the effect of nonsteroidal anti-inflammatory drugs for the prevention or regression of colorectal adenomas and cancer. METHODS: Randomized, controlled trials through September 2003 were identified. Nonsteroidal anti-inflammatory drugs were the interventions. The primary outcomes were the number of patients with at least one colorectal adenoma, a change in polyp burden, or colorectal cancer. The secondary outcome was adverse events. Two reviewers independently extracted data and assessed trial quality. Dichotomous outcomes were reported as relative risks with 95 percent confidence intervals. The data were combined if clinically and statistically reasonable. RESULTS: Nine trials with 150 familial adenomatous polyposis and 24,143 population patients met the inclusion criteria. The interventions included sulindac, celecoxib, or aspirin. From the combined results of three trials, significantly fewer patients in the aspirin group developed recurrent sporadic colorectal adenomas (relative risk, 0.77 (95 percent confidence interval, 0.61, 0.96), number needed to treat 12.5 (95 percent confidence interval, 7.7, 25)) after one to three years. In another three trials, patients with familial adenomatous polyposis who received nonsteroidal anti-inflammatory drugs had a greater proportional reduction (range, 11.9-44 percent) in the number of colorectal adenomas compared with those in the control group (range, 4.5-10 percent). There was no significant difference for the outcomes of colorectal cancer or adverse events in any of the trials. CONCLUSIONS: There is combined evidence from three randomized trials that aspirin significantly reduced the recurrence of sporadic adenomatous polyps. There was evidence from short-term trials to support regression, but not elimination or prevention, of colorectal polyps in familial adenomatous polyposis.

Adenoma↗
PubMed2004

Non steroidal anti-inflammatory drugs (NSAID) and Aspirin for preventing colorectal adenomas and carcinomas.

Editorial note: This review was split in 2012 and the review question was to be addressed according to three new protocols: (See: http://www.cochranelibrary.com/cdsr/doi/10.1002/14651858.CD010267.pub2; http://www.cochranelibrary.com/cdsr/doi/10.1002/14651858.CD010291.pub2; http://www.cochranelibrary.com/cdsr/doi/10.1002/14651858.CD010325.pub2). These titles were withdrawn at the protocol stage in 2020 as the authors did not make any progress on the reviews. This original review will no longer be updated and may be superseded by new titles hosted by Cochrane Gut in the future. BACKGROUND: There is evidence from experimental animals studies, prospective and retrospective observational studies that nonsteroidal anti-inflammatory drugs (NSAIDS) may reduce the development of sporadic colorectal adenomas (CRAs) and cancer (CRC) and may induce the regression of adenomas in familial adenomatous polyposis (FAP). OBJECTIVES: To conduct a systematic review to determine the effect of NSAIDS for the prevention or regression of CRAs and CRC. SEARCH STRATEGY: Randomized controlled trials (RCTs) up to September 2003 were identified. SELECTION CRITERIA: NSAIDS and aspirin (ASA) were the interventions. The primary outcomes were the number of subjects with at least one CRA, the change in polyp burden, and CRC. The secondary outcome was adverse events. DATA COLLECTION AND ANALYSIS: Two reviewers independently extracted data and assessed trial quality. Dichotomous outcomes were reported as relative risks (RR) with 95% confidence intervals (CI). The data were combined with the random effects model if clinically and statistically reasonable. MAIN RESULTS: Nine trials with 150 familial adenomatous polyposis (FAP) and 24,143 population subjects met the inclusion criteria. The interventions included sulindac, celecoxib, or aspirin (ASA). From the combined results of three trials, significantly fewer subjects in the low dose ASA group developed recurrent sporadic CRAs [RR 0.77 (95% CI 0.61, 0.96), (NNT 12.5 (95% CI 7.7, 25)] after one to three years. In another three trials, phenotypic FAP subjects that received sulindac or celecoxib had a greater proportional reduction (range: 11.9% to 44%) in the number of CRAs compared to those in the control group (range: 4.5% to 10%). There was no significant difference for the outcomes of CRC or adverse events in any of the trials. REVIEWERS' CONCLUSIONS: There was evidence from three pooled RCTs that ASA significantly reduces the recurrence of sporadic adenomatous polyps after one to three years. There is evidence from short-term studies to support regression, but not elimination or prevention of CRAs in FAP.

Adenoma↗
PubMed2003

Outcome of patients undergoing liver transplantation for primary sclerosing cholangitis.

PURPOSE: The purpose of this study was to determine the outcome of patients with inflammatory bowel disease who underwent liver transplantation for primary sclerosing cholangitis. METHODS: All patients who underwent liver transplantation for primary sclerosing cholangitis at our institution were identified. A review of patients' hospital and office charts was performed; all patients were then contacted, and a detailed survey was administered by telephone. RESULTS: Sixty-nine patients were identified. There were 53 males (76.8 percent) and 16 females, with a mean age of 45.3 (+/- 13.3) years. Fifty-two (75.4 percent) of the 69 patients had documented inflammatory bowel disease; of these, 40 had ulcerative colitis (76.9 percent), 11 had Crohn's disease, and 1 had indeterminate colitis. Thirty-one patients (60 percent) were diagnosed with inflammatory bowel disease before primary sclerosing cholangitis, with a mean interval to diagnosis of primary sclerosing cholangitis of 10.8 (+/- 10.3) years. Seven patients had both diagnoses made at roughly the same time, and 14 patients initially were diagnosed with primary sclerosing cholangitis and subsequently were found to have inflammatory bowel disease, with a mean interval of 5.2 (+/- 4.4) years; 5 (35.7 percent) of those 14 patients were only diagnosed with inflammatory bowel disease after their liver transplant. The mean time from diagnosis of primary sclerosing cholangitis to liver transplantation was 6.1 (+/- 4.9) years. Since their transplant, 30.8 percent of patients rated their colitis as worse, 38.5 percent felt it was unchanged, and 30.8 percent felt that their colitis was better controlled. Eight (15.4 percent) of the 52 patients with inflammatory bowel disease denied having any knowledge of an increased risk of colorectal neoplasia. Four patients have required colectomy for colorectal neoplasia after liver transplantation, at a mean of 4.7 years after transplantation. Of the patients with inflammatory bowel disease, 42 (80.1 percent) had at least 1 posttransplant surveillance colonoscopy. Eight of the remaining ten patients had a colectomy, leaving only two patients (3.8 percent) who had not been surveyed. However, only 32 (61.5 percent) of the patients with inflammatory bowel disease have been on a surveillance regimen that would approximately conform to current screening recommendations. CONCLUSIONS: The activity of inflammatory bowel disease after transplantation is highly variable. Patients appeared to lack knowledge of their increased risk for colorectal neoplasia. Colorectal cancer is an uncommon but important complication in patients after liver transplantation for primary sclerosing cholangitis, and ongoing surveillance is required. Patients may require education to increase their awareness of the cancer risk and compliance with surveillance.

Chi-Square Distribution↗
PubMed2003

Revising the troublesome stoma: combined abdominal wall recontouring and revision of stomas.

PURPOSE: Despite preoperative siting and maturation of stomas, some patients may have poor stoma function because of redundant pannus, scars, creases, and parastomal or incisional hernias. In these patients, a combined abdominoplasty and stoma revision may be helpful. The object of this manuscript is to report our preliminary results. METHODS: Eight patients (mean age, 48 years; female/male ratio, 7/1) undergoing this procedure are reported. Five patients had inflammatory bowel disease, two had malignancies, and one had multiple sclerosis with bladder and bowel involvement. Patients were contacted at two months to two years follow-up to assess functional outcome and satisfaction with the procedure. RESULTS: Indications for surgery were difficulty maintaining an appliance (n = 7), frequent stool leakage (n = 6), and skin irritation (n = 4). Multiple surgeries (n = 4), skin creases (n = 3), scarring (n = 2), large weight loss (n = 4), and hernias (n = 5) were contributing factors. At surgery five patients had hernias repaired (3 parastomal, 2 incisional), three had stomas resited, and three underwent resections for Crohn's disease. One patient developed a seroma postoperatively. At follow-up six patients were able to maintain an appliance for at least four days, whereas one changed the appliance every three days because of personal preference. None experience stool leakage. All reported a dramatic improvement in body image. CONCLUSION: Combined stoma revision and abdominoplasty can be performed safely and leads to improved functional results and outcome.

Abdominal Muscles↗
PubMed2002

Dietary fibre for the prevention of colorectal adenomas and carcinomas.

BACKGROUND: Colorectal cancer (CRC) is a major cause of morbidity and mortality in industrialized countries. Experimental evidence has supported the hypothesis that dietary fibre may be protective for the development of CRC, although epidemiologic data have been inconclusive. OBJECTIVES: We have conducted a systematic review and meta-analysis to assess the effect of dietary fibre on the incidence or recurrence of colorectal adenomas, the incidence of CRC, and the development of adverse events. SEARCH STRATEGY: We identified randomized controlled trials from Medline, Embase, and the Cochrane Controlled Trials Register up to Oct 2001 SELECTION CRITERIA: Randomized or quasi-randomized controlled trials were assessed. The population included all subjects that had adenomatous polyps but no previous history of colorectal cancer (CRC), a documented "clean colon" at baseline and repeated visualization of the colon/rectum after at least two years of follow-up. Dietary fibre was the intervention. The primary outcomes were the number of subjects with: a) at least one adenoma, b) more than one adenoma, c) at least one adenoma greater than or equal to 1 cm or d) a new diagnosis of CRC. The secondary outcome was the number of adverse events. DATA COLLECTION AND ANALYSIS: Two reviewers independently extracted data, assessed trial quality and resolved discrepancies by consensus. The outcomes were reported as relative risks (RR) and risk difference (RD) with 95% confidence intervals (CI). If statistical significance was reached, the number need to treat (NNTT) or harm (NNTH) was reported. The study data were combined with the fixed effects model if it was clinically, methodologically, and statistically reasonable. MAIN RESULTS: Five studies with 4349 subjects met the inclusion criteria. The interventions were wheat bran fibre, ispaghula husk, or a comprehensive dietary intervention with high fibre whole food sources alone or in combination. When the data were combined there was no difference between the intervention and control groups for the number of subjects with at least one adenoma [RR 1.04 (95% CI 0.95,1.13); RD 0.01 (95% CI 0.02,0.04)]. As well, the combined results for the number of subjects with more than one adenoma [RR 1.02 (95% CI 0.89,1.17), RD 0.00 (-0.02,0.03)] or at least one adenoma 1 cm or greater [RR 0.94 (95% CI 0.77,1.15), RD -0.01 (-0.02,0.01)] were not statistically significant. Other primary and secondary outcomes and subanalyses by type of fibre intervention were not statistically or clinically significant. REVIEWER'S CONCLUSIONS: There is currently no evidence from RCTs to suggest that increased dietary fibre intake will reduce the incidence or recurrence of adenomatous polyps within a two to four year period.

Adenoma↗
PubMed2002

Pregnancy, delivery, and pouch function after ileal pouch-anal anastomosis for ulcerative colitis.

PURPOSE: This study was designed to evaluate the pregnancies, method of delivery, and functional results of females with chronic ulcerative colitis who have an ileal pouch-anal anastomosis. METHODS: A mailed questionnaire was sent to all females with an ileal pouch-anal anastomosis for chronic ulcerative colitis. Information on the pregnancy, method of delivery, and outcome was collected. Those females who had a successful pregnancy and delivery were contacted by telephone to clarify results and determine pouch functional results. Other clinical information was obtained from the Mount Sinai Hospital Inflammatory Bowel Disease database. RESULTS: Thirty-eight subjects had 67 pregnancies. Of these, 29 subjects had 49 deliveries. There were 25 vaginal deliveries and 24 cesarean sections. There were two pouch-related complications during the pregnancies and four pouch-related complications postpartum. All were treated nonoperatively. Stool frequency and day and night incontinence were increased during pregnancy in most subjects, but after delivery, prepregnancy function was restored in 24 (83 percent) of them. Five subjects (17 percent) had some degree of permanent deterioration in pouch function. Of these, three had vaginal deliveries, and two had cesarean sections. Multiple births and birth weight were not found to adversely affect subsequent pouch function. CONCLUSION: Pregnancy is safe in females with ileal pouch-anal anastomosis. Functional results are altered almost exclusively during the third trimester, but pouch function promptly returns to prepregnancy status in most females. A small proportion of females have long-term disturbances in function, but these are not related to the method of delivery. Thus, the method of delivery should be dictated by obstetric considerations.

Adult↗
PubMed2001

Identification of a critical lysine residue in apolipoprotein B-100 that mediates noncovalent interaction with apolipoprotein(a).

We have previously shown that lipoprotein(a) (Lp(a)) assembly involves an initial noncovalent interaction between sequences within apolipoprotein(a) (apo(a)) kringle IV types 5-8 and the amino terminus of apolipoprotein B-100 (sequences between amino acids 680 and 781 in apoB-100), followed by formation of a disulfide bond. In the present study, citraconylation of lysine residues in apoB-100 abolished the ability of the modified low density lipoprotein to associate with apo(a), thereby demonstrating a direct role for lysine residues in apoB in the first step of Lp(a) assembly. To identify specific lysine residues in the amino terminus of apoB that are required for the noncovalent interaction, we initially used an affinity chromatography method in which recombinant forms of apo(a) (r-apo(a)) were immobilized on Sepharose beads. Assessment of the ability of carboxyl-terminal truncations of apoB-18 to bind to r-apo(a)-Sepharose revealed that a 25-amino acid sequence in apoB (amino acids 680-704) bound specifically to apo(a) in a lysine-dependent manner; citraconylation of the lysine residues in the apoB derivative encoding this sequence abolished the binding interaction. Using fluorescence spectrometry, we found that a synthetic peptide corresponding to this sequence bound directly to apo(a); the peptide also reduced covalent Lp(a) formation. Lysine residues present in this sequence (Lys(680) and Lys(690)) were mutated to alanine in the context of apoB-18. We found that the apoB-18 species containing the Lys(680) mutation was incapable of binding to r-apo(a)-Sepharose columns, whereas the apoB-18 species containing the Lys(690) mutation exhibited slightly reduced binding to these columns. Taken together, our data indicate that Lys(680) is critical for the noncovalent interaction of apo(a) and apoB-100 that precedes covalent Lp(a) formation.

Alanine↗
PubMed2001

The insulin-stimulated cell surface presentation of low density lipoprotein receptor-related protein in 3T3-L1 adipocytes is sensitive to phosphatidylinositide 3-kinase inhibition.

The regulation of low density lipoprotein receptor-related protein (LRP) activity by insulin was studied using 3T3-L1 adipocytes. The LRP mRNA and protein expression were independent of differentiation state of the cells and of insulin treatment. In differentiated cells, insulin treatment acutely stimulated the cell surface presentation of LRP (approximately 2-fold) as evidenced by methylamine-activated alpha(2)-macroglobulin binding and by biotinylation of cell surface LRP. The increased cell surface presentation was accompanied by a 39% decrease in LRP level in the low density microsomes. The magnitude of insulin-stimulated cell surface presentation of LRP was similar to that of transferrin receptor but was much less than that of GLUT4. Both the increases in LRP and GLUT4 cell surface presentation upon insulin treatment were abolished by inhibition of phosphatidylinositide 3-kinase. The increased cell surface presentation of LRP was associated with proportionally increased endocytic activity, and the internalization rate constant (K(e)) was not decreased by insulin treatment. Thus, insulin treatment most likely stimulates recycling of LRP from an endosomal pool to the plasma membrane, which is regulated in a phosphatidylinositide 3-kinase-dependent manner in 3T3-L1 adipocytes.

3T3 Cells↗
PubMed2001

Extended follow-up of patients treated with cytotoxic chemotherapy for intra-abdominal desmoid tumors.

BACKGROUND: Cytotoxic chemotherapy can achieve a good initial response in inoperable desmoid tumors that have caused progressive obstruction of the gastrointestinal and urinary tracts and have caused unrelenting pain. METHODS: We have reviewed 8 patients (3 male) with desmoid tumors and familial adenomatous polyposis who underwent cytotoxic chemotherapy for inoperable gastrointestinal obstruction and/or uncontrolled pain. They were treated with doxorubicin and dacarbazine followed by carboplatin and dacarbazine. RESULTS: Follow-up after cytotoxic chemotherapy in the 7 patients for whom it was available was a mean of 42 (range 24-54) months. Two patients achieved complete remission after therapy. Four patients achieved a partial remission after completing all or some of the chemotherapy regimen; of these, three remained in stable remission, whereas the other was lost to follow-up. There were two recurrences that required further therapy; one of these patients was treated with further chemotherapy, which induced a second remission, and the other was treated with pelvic exenteration and has subsequently died. CONCLUSIONS: Most patients had a substantial response to cytotoxic chemotherapy; however, two patients required additional therapy 24 and 30 months after cytotoxic chemotherapy, respectively. Cytotoxic chemotherapy is effective in producing short-term and long-term remission in these difficult patients.

Adenomatous Polyposis Coli↗
PubMed2001

Carrier rate of APC I1307K is not increased in inflammatory bowel disease patients of Ashkenazi Jewish origin.

Colorectal cancer (CRC) occurs with an increased incidence in individuals with chronic inflammatory bowel disease (IBD) of the colon. Recent data suggest that a family history of colorectal cancer is an independent risk factor for CRC in IBD, an observation that implies that genetic factors are relevant to the development of CRC in this context. Among the genetic defects associated with CRC, the APC I1307K mutation has been detected nearly exclusively in individuals of Ashkenazi Jewish (AJ) origin, occurring in 6%-7% of the AJ general population and in 10%-28% of AJ with a either a personal or family history of CRC or adenomatous polyps. These findings, together with the increased incidence of IBD in AJ, prompted the current analysis of the contribution of the APC I1307K variant of CRC in AJ IBD patients. APC I1307K carrier frequencies were determined in 306 AJ individuals affected with IBD and 308 of their unaffected relatives ascertained from a family collection obtained for the identification of IBD susceptibility genes. Prevalence of the I1307K variant was not significantly different among individuals with IBD, Crohn's disease, ulcerative colitis, and unaffected relatives (6.9%, 7.6%, 4.7%, and 6.2%, respectively), and the mutation was detected in only one of five IBD-affected individuals with a diagnosis of CRC. These results reveal that IBD patients of AJ origin carry the APC I1307K variant at the same rate as individuals within the general AJ population. Lack of an increased APC I1307K carrier rate suggests that this mutation does not account for the increased CRC susceptibility associated with IBD.

Adult↗
PubMed2001

Genetic variation in the 5q31 cytokine gene cluster confers susceptibility to Crohn disease.

Linkage disequilibrium (LD) mapping provides a powerful method for fine-structure localization of rare disease genes, but has not yet been widely applied to common disease. We sought to design a systematic approach for LD mapping and apply it to the localization of a gene (IBD5) conferring susceptibility to Crohn disease. The key issues are: (i) to detect a significant LD signal (ii) to rigorously bound the critical region and (iii) to identify the causal genetic variant within this region. We previously mapped the IBD5 locus to a large region spanning 18 cM of chromosome 5q31 (P<10(-4)). Using dense genetic maps of microsatellite markers and single-nucleotide polymorphisms (SNPs) across the entire region, we found strong evidence of LD. We bound the region to a common haplotype spanning 250 kb that shows strong association with the disease (P< 2 x 10(-7)) and contains the cytokine gene cluster. This finding provides overwhelming evidence that a specific common haplotype of the cytokine region in 5q31 confers susceptibility to Crohn disease. However, genetic evidence alone is not sufficient to identify the causal mutation within this region, as strong LD across the region results in multiple SNPs having equivalent genetic evidence-each consistent with the expected properties of the IBD5 locus. These results have important implications for Crohn disease in particular and LD mapping in general.

Chromosome Mapping↗
PubMed2001

Risk of dysplasia in long-term ileal pouches and pouches with chronic pouchitis.

BACKGROUND & AIMS: Recent reports have suggested the mucosa of an ileal reservoir could be at risk of neoplasia. Risk factors may include the age of the pouch, chronic pouchitis, and previous colonic neoplasia. This study examined a group of such patients to determine the risk of dysplasia. METHODS: From a cohort of 1221 patients with ileal pouches, 171 patients with possible risk factors were selected. Successful contact was made with 138 patients who were invited for endoscopy and multiple biopsies. Biopsy specimens were stained with H&E and p53, scored for inflammatory changes including villous atrophy, and analyzed by flow cytometry. RESULTS: One hundred six patients took part and fell into 1 or more of the following clinical categories: chronic pouchitis (n = 34), pelvic pouch for > or =12 years (n = 42); Kock pouch for > or =14 years (n = 29), and neoplasia in colectomy specimen (n = 11). Thirty-three patients had severe villous atrophy. One patient of 106 (95% confidence interval, 0.9% +/- 1.6%) with a long-standing pouch had low-grade dysplasia that was multifocal. DNA analysis by flow cytometry showed aneuploidy in this patient and 2 others. CONCLUSIONS: These data suggest that the development of dysplasia in ileal pouches performed for ulcerative colitis is probably a rare event within 15-20 years of pouch surgery.

Adult↗
PubMed2001

Subcutaneous heparin versus low-molecular-weight heparin as thromboprophylaxis in patients undergoing colorectal surgery: results of the canadian colorectal DVT prophylaxis trial: a randomized, double-blind trial.

OBJECTIVE: To compare the effectiveness and safety of low-dose unfractionated heparin and a low-molecular-weight heparin as prophylaxis against venous thromboembolism after colorectal surgery. METHODS: In a multicenter, double-blind trial, patients undergoing resection of part or all of the colon or rectum were randomized to receive, by subcutaneous injection, either calcium heparin 5,000 units every 8 hours or enoxaparin 40 mg once daily (plus two additional saline injections). Deep vein thrombosis was assessed by routine bilateral contrast venography performed between postoperative day 5 and 9, or earlier if clinically suspected. RESULTS: Nine hundred thirty-six randomized patients completed the protocol and had an adequate outcome assessment. The venous thromboembolism rates were the same in both groups. There were no deaths from pulmonary embolism or bleeding complications. Although the proportion of all bleeding events in the enoxaparin group was significantly greater than in the low-dose heparin group, the rates of major bleeding and reoperation for bleeding were not significantly different. CONCLUSIONS: Both heparin 5,000 units subcutaneously every 8 hours and enoxaparin 40 mg subcutaneously once daily provide highly effective and safe prophylaxis for patients undergoing colorectal surgery. However, given the current differences in cost, prophylaxis with low-dose heparin remains the preferred method at present.

Anticoagulants↗