SMAD2 and the Relationship of Colorectal Cancer to Inflammatory Bowel Disease

Inflammatory bowel diseases (IBDs) affecting the colon [Crohn's disease (CD) and ulcerative colitis (UC)] are associated with an increased risk of colorectal cancer (CRC). Our previous work using oligonucleotide array data indicated that SMAD2 was significantly underexpressed in UC dysplastic tissue compared to benign UC. The aim of this current study was to determine whether single nucleotide polymorphisms (SNPs) within the SMAD2 gene are associated with IBD dysplasia/cancer. We performed an SNP haplotype-based case-control association study. Leukocyte DNA was obtained from 489 unrelated Caucasians (158 UC, 175 CD, 71 CRC, 85 controls). Eleven SNPs were genotyped. All 11 SNPs were in Hardy-Weinberg equilibrium in the control population. Strong linkage disequilibrium was observed among nearly all SMAD2 SNPs. There were no significant associations between SMAD2 allele or haplotype frequencies. Power calculations indicated good power for single-marker analysis (>0.8) and reasonably good power against effects of 0.1–0.15 for haplotype analysis. SMAD2 SNPs were not associated with the development of IBD dysplasia/cancer. This incongruity between our previous microarray data and the findings from this genotype study may be attributed to mechanisms such as alternative splicing of pre-mRNA SMAD2 and/or cross talk with other cellular pathways.

Surgical behaviour

Do the best for the patient

Assessment of publication bias for the surgeon scientist

Background

Publication bias occurs when statistically non-significant (negative) findings are not published. It can profoundly affect the results of systematic reviews and meta-analyses.

Methods

Qualitative and quantitative methods of detecting publication bias are described, including their advantages and disadvantages.

Results and conclusion

Accepted quality standards for the reporting of meta-analyses recommend assessment of publication bias, but currently there is no uniform standard for reporting. Quantitative methods are being used with increasing frequency. Authors should take steps to minimize publication bias, and use both qualitative and quantitative assessment methods to determine whether it is present.

Meta-analysis: antibiotic prophylaxis to prevent peristomal infection following percutaneous endoscopic gastrostomy

BACKGROUND

Despite numerous guidelines recommending prophylactic antibiotics prior to percutaneous endoscopic gastrostomy, their use remains controversial.

AIM

To conduct a systematic literature review and performed meta-analyses to determine the benefit of antibiotic prophylaxis for percutaneous endoscopic gastrostomy placement.

METHODS

We performed a systematic literature review by searching healthcare databases and grey literature for randomized-controlled trials of antibiotic prophylaxis against wound infection after percutaneous endoscopic gastrostomy. Relative risks were calculated for individual trials and data pooled using fixed-effects model. Relative risk reduction, absolute risk reduction and number needed to treat were calculated and are reported with 95% confidence intervals.

RESULTS

Ten randomized-controlled trials met the inclusion criteria and 1059 cases were pooled. Overall findings indicated that antibiotic prophylaxis resulted in a relative risk reduction of 64% and an absolute risk reduction of 15%. Number needed to treat to prevent one wound infection was 8. Cephalosporin prophylaxis was associated with a relative risk reduction of 64%, absolute risk reduction of 10% and number needed to treat of 10, whereas penicillin-based prophylaxis was associated with a relative risk reduction of 62%, absolute risk reduction of 13% and number needed to treat of 8.

CONCLUSIONS

Antibiotic prophylaxis prior to percutaneous endoscopic gastrostomy is effective in reducing the incidence of percutaneous endoscopic gastrostomy site wound infection. Based on sensitivity analyses, penicillin-based prophylaxis should be the prophylaxis of choice.

Systematic reviews and meta-analysis for the surgeon scientist

BACKGROUND

Understanding of data-reporting methods is imperative for correct interpretation of the medical literature as well as for proper performance of future clinical research. Recent developments in biostatistics have greatly changed the types of statistical analyses used and the minimum quality standards that must be maintained.

METHOD

Different types of review are described, including systematic review with and without meta-analysis. Minimum reporting standards, sources of bias, both quantitative and qualitative, and references are discussed.

RESULTS AND CONCLUSION

Meta-analysis has become a clearly defined technique, with reporting standards for both randomized controlled trials and observational studies. It is assuming a wider role in the surgical literature. Although many sources of bias exist, there are clear reporting standards and readers should be aware of these when studying the literature.

Legislative threat to clinical science-the obfuscation and de-identification of protected health information

A salutary tale

Effect of intra-operative end-tidal carbon dioxide partial pressure on tissue oxygenation

Postsurgical infection risk is correlated with subcutaneous tissue oxygenation. Mild hypercapnia augments cutaneous perfusion. We tested the hypothesis that peripheral tissue oxygenation increases as a function of arterial PCO2 in surgical patients. Twenty patients were randomly assigned to intra-operative end tidal PCO2 of 3.99 (control) or 5.99 kPa (hypercapnia). All other anaesthetic management was per protocol. Tissue oxygen partial pressure, transcutaneous oxygen tension, cerebral oxygen saturation, and cardiac output were measured. Mean (SD) subcutaneous tissue oxygen tension was 8.39 (1.86) kPa in control and 11.84 (2.53) kPa hypercapnia patients (p = 0.014). Cerebral oxygen saturation was 55 (4)% for control vs. 68 (9)% for hypercapnia (p = 0.004). Neither cardiac index nor transcutaneous tissue oxygen tension differed significantly between the groups. Mild intra-operative hypercapnia increased subcutaneous and cerebral oxygenation. Increases in subcutaneous tissue oxygen partial pressure similar to those observed in patients assigned to hypercapnia are associated with substantial reductions in wound infection risk.

Omental transposition for low pelvic anastomoses

Surgeons' opinions differ regarding the role of the omentum in low pelvic intestinal anastomoses. This study was undertaken to define the anatomy and surgical technique of omental transposition to the pelvis. We studied 45 cadavers to elucidate surgical aspects of omental mobilization, lengthening, and transposition into the pelvic cavity. In addition, intraoperative studies of omental transposition to the pelvis were performed in 20 patients with chronic ulcerative colitis, familial adenomatous polyposis, and rectal cancer who were undergoing ileal J-pouch anal anastomosis or low anterior resection. The most important anatomic variables for omental transposition are three variants of arterial blood supply: (1) In 56% of patients, there is one right, one (or two) middle, and one left omental artery. (2) In 26% of patients, the middle omental artery is absent. (3) In the remaining 18% of patients, the gastroepiploic artery is continued as a left omental artery but with various smaller connections to the right or middle omental artery. The first stage of omental lengthening is detachment of the omentum from the transverse colon mesentery. This must be performed carefully, as the omentum is closely adherent to the right transverse mesocolon. The second stage is the actual lengthening of the omentum. The third stage is placement of the omental flap into the pelvis. Creation of an omental pedicle is a simple surgical procedure. This procedure can be performed quickly, does not involve significant blood loss, and may reduce the frequency of complications after low pelvic anastomoses.

Identification of candidate genes in ulcerative colitis and Crohn's disease using cDNA array technology

Inflammatory bowel disease (IBD) follows a multigenic mode of inheritance, encompassing the clinically discrete phenotypes of ulcerative colitis (UC) and Crohn's disease (CD). The risk of malignant transformation of the colon increases with the duration and extent of IBD and is particularly high for patients with a longstanding history of UC. We wished to identify candidate genes that might be involved in disease pathogenesis based on functional plausibility and their putative role in IBD carcinogenesis. Polyadenylated mRNA (PolyA+ mRNA) preparation from inflamed intestinal mucosa of patients with a longstanding history of UC and CD was performed with subsequent hybridization of alpha phosphorus [alpha-32P]-deoxyadenotriphosphate-labeled complementary deoxyribonucleic acid (DNA) populations to nucleic acid arrays. Of 588 different human gene transcripts arrayed, secreted apoptosis-related protein 1 (Sarp1), frizzled (fz) homologues, and disheveled (dvl) were differentially expressed, being elevated in UC as compared to CD. These genes encode proteins involved in the Wingless-type (Wnt)/beta-catenin signaling pathway. The autonomous expression of Sarp1 and Sarp1-compatible fz receptor genes suggests that the Wnt pathway may be involved in UC carcinogenesis.

Wingless-type frizzled protein receptor signaling and its putative role in human colon cancer

We wish to identify new candidate genes involved in the pathogenesis of human colon cancer to better understand the diversity of phenotype presentation that varies from individual to individual. Our working hypothesis is that genetic polymorphism of genes in the Wingless-type (Wnt) frizzled protein receptor pathway is associated with the susceptibility to develop colon cancer. The putative role of the Wnt pathway in sporadic human malignancy of the colon suggests involvement in inherited cancer as well. beta-catenin is the crucial messenger in frizzled receptor signaling, transmitting Wnt-ligand signals such as signals from secreted apoptosis-related proteins to the nucleus. It functions as a genome denunciator by initiating amplification of oncogenes. The net effect of beta-catenin depends on the magnitude of its accumulation in the cytoplasm and, therefore, upon expression profiles of genes in the Wnt pathway. We propose that variations in allelic frequencies of genes involved in the beta-catenin cascade may either promote or impede malignant transformation of the colon. If certain polymorphisms in Wnt signaling through beta-catenin predispose to colon cancer, this might manifest as decreased binding affinity of proteins such as axin or the adenomatous polyposis coli protein to beta-catenin. Association studies are proposed to test the hypothesis, which could serve as an initial step toward understanding the complexity of tumor biology. The clinical rationale in unraveling the genetic susceptibility to cancer lies in identification of a subgroup of individuals who may benefit from beta-catenin targeting agents, which could potentially overcome this genetic instability.

Association of susceptibility locus for inflammatory bowel disease on chromosome 16 with both ulcerative colitis and Crohn's disease

A susceptibility locus for inflammatory bowel disease (IBD) on chromosome 16 (IBD1) has been linked to Crohn's disease in genome-wide linkage studies. We performed a case-control study with two markers for this locus using leukocyte DNA from 127 Crohn's patients, 83 ulcerative colitis patients, and 74 control patients. Allele, genotype, and haplotype frequencies of the polymerase chain reaction products were determined using autoradiography. Haplotype frequencies differed for ulcerative colitis and Crohn's disease, particularly for haplotype CC (22% ulcerative colitis vs 10% Crohn's disease, P = 0.002 Chi2 = 10.0) and haplotype CD (18% Crohn's disease vs 9% ulcerative colitis, P = 0.025 Chi2 = 5.02). These data demonstrate the association of the IBD1 locus with both ulcerative colitis and Crohn's disease in a group of unrelated IBD patients. The use of such microsatellite markers when combined with others, might help distinguish ulcerative colitis from Crohn's disease in patients with ambiguous clinical and histological features.

Dynamic rectus abdominis muscle sphincter for stoma continence: an acute functional study in a dog model

Fecal stomal incontinence is a problem that continues to defy surgical treatment. Previous attempts to create continent stomas using dynamic myoplasty have had limited success due to denervation atrophy of the muscle flap used in the creation of the sphincter and because of muscle fatigue resulting from continuous electrical stimulation. To address the problem of denervation atrophy, a stomal sphincter was designed using the most caudal segment of the rectus abdominis muscle, preserving its intercostal innervation as well as its vascular supply. The purpose of the present study was to determine whether this rectus abdominis muscle island flap sphincter design could maintain stomal continence acutely. In this experiment, six dogs were used to create eight rectus abdominis island flap stoma sphincters around a segment of distal ileum. Initially, the intraluminal stomal pressures generated by the sphincter using different stimulation frequencies were determined. The ability of this stomal sphincter to generate continence at different intraluminal bowel pressures was then assessed. In all cases, the rectus abdominis muscle sphincter generated peak pressures well above those needed to maintain stomal continence (60 mmHg). In addition, each sphincter was able to maintain stomal continence at all intraluminal bowel pressures tested.

The importance of diagnostic accuracy in colonic inflammatory bowel disease

OBJECTIVE

Crohn's disease (CD) and ulcerative colitis (UC) may both affect the colon. However, in approximately 10-20% of these cases, it is impossible to distinguish between these two entities either clinically or histologically, and a diagnosis of indeterminate colitis (IC) is made. Correct diagnosis is important because surgical treatment and long-term prognosis differ for UC and CD. The purpose of this study was to determine the extent of interobserver agreement among board-certified pathologists and a specialist gastrointestinal (GI) pathologist regarding the histological diagnosis of colonic inflammatory bowel disease (IBD).

METHODS

A total of 24 university medical center pathologists from eight institutions evaluated 84 colectomy specimens and 35 sets of biopsy specimens from 119 consecutive patients with colonic IBD. A specialist GI pathologist subsequently reviewed all cases without knowledge of clinical data and prior diagnosis.

RESULTS

The GI pathologist's diagnoses differed from the initial diagnoses in 45% of surgical specimens and 54% of biopsy specimens. Of 70 cases initially diagnosed as UC, 30 (43%) were changed to CD or IC, whereas 4 of 23 cases (17%) initially diagnosed as CD were changed to UC or IC. The kappa coefficient for the overall agreement of initial diagnoses with the specialist GI pathologist's diagnoses was -0.01 (p = 0.98).

CONCLUSIONS

There is significant interobserver variation in the histological diagnosis of colonic IBD. This may have a profound effect on clinical patient care and, especially, on the choice of operation. More accurate diagnostic criteria are needed to facilitate patient care and to optimize treatment outcome.

The importance of diagnostic accuracy in colonic inflammatory bowel disease

OBJECTIVE

Crohn's disease (CD) and ulcerative colitis (UC) may both affect the colon. However, in approximately 10-20% of these cases, it is impossible to distinguish between these two entities either clinically or histologically, and a diagnosis of indeterminate colitis (IC) is made. Correct diagnosis is important because surgical treatment and long-term prognosis differ for UC and CD. The purpose of this study was to determine the extent of interobserver agreement among board-certified pathologists and a specialist gastrointestinal (GI) pathologist regarding the histological diagnosis of colonic inflammatory bowel disease (IBD).

METHODS

A total of 24 university medical center pathologists from eight institutions evaluated 84 colectomy specimens and 35 sets of biopsy specimens from 119 consecutive patients with colonic IBD. A specialist GI pathologist subsequently reviewed all cases without knowledge of clinical data and prior diagnosis.

RESULTS

The GI pathologist's diagnoses differed from the initial diagnoses in 45% of surgical specimens and 54% of biopsy specimens. Of 70 cases initially diagnosed as UC, 30 (43%) were changed to CD or IC, whereas 4 of 23 cases (17%) initially diagnosed as CD were changed to UC or IC. The kappa coefficient for the overall agreement of initial diagnoses with the specialist GI pathologist's diagnoses was -0.01 (p = 0.98).

CONCLUSIONS

There is significant interobserver variation in the histological diagnosis of colonic IBD. This may have a profound effect on clinical patient care and, especially, on the choice of operation. More accurate diagnostic criteria are needed to facilitate patient care and to optimize treatment outcome.

What's new with tumor markers for colorectal cancer?

BACKGROUND/AIMS

Many tumor markers have been utilized in the follow-up care of colorectal cancer patients. No marker, however, has proven reliably accurate in detecting recurrent disease.

METHODS

The strengths and weaknesses of currently available tumor markers are reviewed, with attention to related cost and efficacy.

RESULTS

Tumor antigens, enzymes, and genetic markers have been used as tumor markers. CEA and CA 19.9 are the most widely utilized; however, genetic markers are the most promising for the future.

CONCLUSIONS

Currently available markers have significant limitations. Development of genetic markers may greatly enhance our ability to predict prognosis and the need for adjuvant therapy. Marker-guided therapy may play an increasing role in this disease.

Impact of sedation and resident teaching on complications of colonoscopy

There is controversy regarding the frequency of sedation-related complications of colonoscopies and whether these procedures are safely performed by physicians-in-training. We retrospectively reviewed the safety of 1,004 consecutive outpatient colonoscopies. No perforations occurred. No patients were hospitalized for sedation-related complications. Seventeen percent of patients had significant changes in vital signs that lasted less than 5 min. These changes were less common in patients receiving </=3 mg midazolam intravenously without meperidine (p < 0.005). Complications were slightly more frequent in procedures performed by trainees (23%) than by gastroenterologists (12%) and by surgeons (18%) (p = 0.01). These data support the safety of colonoscopy under intravenous sedation, even when performed by trainees.

Safety and efficacy of dynamic graciloplasty for fecal incontinence: report of a prospective, multicenter trial. Dynamic Graciloplasty Therapy Study Group

PURPOSE

Dynamic graciloplasty has been used for intractable fecal incontinence, and good results have been reported. The aim of this study was to assess prospectively the safety and efficacy of dynamic graciloplasty for intractable fecal incontinence in a prospective, multicenter trial.

METHODS

A total of 123 adults were treated with dynamic graciloplasty at 20 institutions. Continence was assessed preoperatively and postoperatively by use of 14-day diaries.

RESULTS

There was one treatment-related death. One hundred eighty-nine adverse events occurred in 91 patients (74 percent). Forty-nine patients (40 percent) required one or more operations to treat complications. One hundred seventy (90 percent) events were resolved. Sixty-three percent of patients without pre-existing stomas recorded a 50 percent or greater decrease in incontinent events 12 months after dynamic graciloplasty, and an additional 11 percent experienced lesser degrees of improvement. Twenty-six percent were not improved, worsened, or exited. In patients with pre-existing stomas, 33 percent achieved successful outcomes at 12 months. This number increased to 60 percent at 18 months. Seventy-eight percent of patients had increased enema retention time, and mean anal canal pressures improved significantly at 12 months. Significant changes in quality of life were also observed.

CONCLUSIONS

Objective improvement can be demonstrated in the majority of patients with end-stage fecal incontinence treated with dynamic graciloplasty. Reduction in incontinence episodes can be correlated with improved quality of life. Adverse events are frequently encountered, but most resolve with treatment.

Use of a microsatellite marker in predicting dysplasia in ulcerative colitis

BACKGROUND

Patients with ulcerative colitis (UC) have an increased risk of developing colorectal cancer. The current screening protocol involves an annual colonoscopy and biopsy after the patient has had the disease for 8 years. This, however, does not prevent the development of colorectal cancer.

HYPOTHESIS

A microsatellite marker for IBD1 may identify individuals who are at greater risk of developing dysplasia and therefore colorectal cancer.

DESIGN

Case-control study.

SETTING

Single surgical practice.

PATIENTS AND METHODS

DNA was extracted from peripheral leukocytes of 152 patients: 22 with UC and dysplasia; 48 with UC and no dysplasia; 24 with colorectal cancer; and 58 with noninflammatory bowel disease, nonmalignant gastrointestinal tract disease who were used as control patients. A microsatellite marker for IBD1 (D16S541) was amplified by polymerase chain reaction. Genotypes were identified using autoradiography.

RESULTS

Six alleles and 15 genotypes were identified for marker D 16S541. Genotype CC was found in 33% (8/24) of cancer patients but only 12% (7/58) of controls (chi2 = 5.5; P = .02). Thirty-two percent (7/22) of patients with dysplastic UC also had this genotype, whereas only 8% (4/ 48) of patients with nondysplastic UC had the genotype (chi2 = 4.6; P = .03; vs controls: chi2 = 3.1; P = .08).

CONCLUSIONS

This microsatellite marker for IBD1, when combined with other markers, has the potential to be used as a screening tool for colorectal cancer and dysplasia in patients with UC. Such a marker would be of particular use in improving the sensitivity and specificity of the current screening protocol for dysplasia and colorectal cancer for patients with UC.

Effect of PGG-glucan on the rate of serious postoperative infection or death observed after high-risk gastrointestinal operations. Betafectin Gastrointestinal Study Group

BACKGROUND

Postoperative infections remain common after high-risk gastrointestinal procedures. PGG-glucan (Betafectin; Alpha Beta Technology Inc, Worcester, Mass), derived from yeast cell walls, promotes phagocytosis and intracellular killing of bacterial pathogens by leukocytes, prevents infection in an animal model of wound infection, and acts synergistically with antibiotics to reduce mortality in rat peritonitis.

HYPOTHESIS

We hypothesized that infectious complications in these patients might be reduced by the administration of a nonspecific immune-enhancing agent.

DESIGN

Multicenter, prospective, randomized, double-blind, placebo-controlled trial of 1249 patients prospectively stratified into colorectal or noncolorectal strata.

SETTING

Thirty-nine medical centers throughout the United States.

PATIENTS

Aged 18 years or older, scheduled for gastrointestinal procedure lasting 2 to 8 hours, with 2 or more defined risk factors.

INTERVENTIONS

PGG-glucan, 0.5 mg/kg or 1.0 mg/kg, or placebo once preoperatively and 3 times postoperatively. All patients received standardized antibiotic prophylaxis.

MAIN OUTCOME MEASURES

Serious infection or death within 30 days.

RESULTS

All randomized patients revealed no difference in serious infections and deaths in the treated groups compared with placebo groups (15% vs 14%, P>.90). In the prospectively defined noncolorectal stratum (n = 391), PGG-glucan administration was associated with a statistically significant relative reduction (39%) in serious infections and death (placebo, 46 [36%] of 129 vs either PGG-glucan group, 29 [21%] of 132 and 28 [22%] of 130, P<.02). PGG-glucan reduced postoperative infection or death in malnourished patients having noncolorectal procedures (31 [44%] of 70, placebo group; 16 [24%] of 68, 0.5-mg/kg PGG-glucan group; 12 [17%] of 72, 1.0-mg/kg PGG-glucan group; P<.001). Study drug was stopped owing to adverse effects more frequently for patients receiving PGG-glucan than placebo (2%, 4%, and 7% for the placebo group, 0.5-mg/kg PGG-glucan group, and 1.0-mg/kg PGG-glucan group, respectively, P<.003).

CONCLUSION

Perioperative administration of PGG-glucan reduced serious postoperative infections or death by 39% after high-risk noncolorectal operations.

Preliminary evaluation of safety and activity of recombinant human interleukin 11 in patients with active Crohn's disease

BACKGROUND & AIMS

Recombinant human interleukin 11 (rhIL-11) is a cytokine with thrombocytopoietic activity and anti-inflammatory and mucosal protective effects. The objectives of this study were to investigate the safety and tolerability of rhIL-11 in patients with Crohn's disease and to explore the effects of dose and schedule on platelet count and Crohn's disease activity.

METHODS

A multicenter, double-masked, placebo-controlled, dose-escalation study of 76 patients with active Crohn's disease was performed. Patients were randomized to receive subcutaneous placebo or rhIL-11 at doses of 5, 16, or 40 microgram. kg-1. wk-1 given 2 or 5 times weekly for 3 weeks. Clinical and laboratory safety data were recorded, and disease activity was measured at each visit.

RESULTS

Subcutaneous injection of rhIL-11 generally was well tolerated. Significantly greater increases in platelet counts were found among patients receiving rhIL-11 40 microgram. kg-1. wk-1 as 2 or 5 weekly doses and 16 microgram. kg-1. week-1 as 5 weekly doses compared with patients receiving placebo (P < 0.05). Patients receiving 16 microgram. kg-1. wk-1 had the highest clinical response rates, with a response seen in 42% of patients (5/12) receiving 5 weekly doses and 33% of patients (4/12) receiving 2 weekly doses, compared with 7% of patients (1/15) receiving placebo.

CONCLUSIONS

Short-term treatment with rhIL-11 is well tolerated in patients with active Crohn's disease. The thrombocytopoietic effect of rhIL-11 seems to be both dose and schedule dependent and may be minimized with retained clinical benefit in Crohn's disease at 16 microgram. kg-1. wk-1 given in 2 equal doses.

Limited utility of preoperative studies in preparation for colostomy closure

Numerous diagnostic and therapeutic practices are used in an attempt to reduce the morbidity of colostomy closures. Our principal aim was to evaluate the role of preoperative studies, specifically barium enemas and endoscopic examinations, performed before colostomy closures. Additionally, we wished to identify other practices involved in the perioperative management of patients undergoing colostomy closure that influenced morbidity. The records of 100 consecutive patients who underwent elective colostomy closure at University of Louisville Hospital between January 1989 and July 1995 were reviewed. Wound infection was the most common complication (12%). Various bowel preparations were equivalent in efficacy and did not influence the complication rate. Intermittent wound irrigation with antibiotics for 3 days postoperatively, via subcutaneous drains, was associated with a low incidence of incision infection. Preoperative barium enema or sigmoidoscopy were often performed but rarely useful. Performing these examinations merely increased hospital cost without a corresponding decline in morbidity.

Analysis of minocycline by high-performance liquid chromatography in tissue and serum

A sensitive and rapid reversed-phase high-performance liquid chromatography assay can be used to accurately determine serum and tissue minocycline concentrations. Minocycline is a broad spectrum tetracycline derivative with many applications. Tissue and serum samples were obtained from guinea pigs that had received either topical or intravenous minocycline. Samples were extracted using a Sep-Pak C18 cartridge and were injected into a microBondapak C18 column with an isocratic methanol mobile phase. Samples were analyzed using UV detection and produced sharp peaks with a retention time of 2.5 min. The lower limit of detection was 100 ng and drug recovery was 61%. This method greatly facilitated the analysis of minocycline while allowing for sensitivity.

Suppository administration of chemotherapeutic drugs with concomitant radiation for rectal cancer

PURPOSE

Preoperative radiation with combined chemotherapy is effective in shrinking advanced rectal cancer locally and facilitating subsequent surgery. Suppository delivery of 5-fluorouracil is associated with less toxicity and higher rectal tissue concentrations than intravenous administration. This prompted us to evaluate suppository and intravenous administration of 5-fluorouracil and mitomycin C with concomitant radiation to determine associated toxicity.

METHODS

Rectal, liver, lymph node, and lung tissue and systemic and portal blood were collected serially from male Sprague Dawley rats to determine drug concentrations following suppository or intravenous delivery of 5-fluorouracil or mitomycin C. Thirty-six animals were randomly assigned to treatment groups and received 5-fluorouracil suppositories, mitomycin C suppositories, or an equivalent intravenous dose of 5-fluorouracil or mitomycin C 30 minutes before radiation therapy. Before and 3, 6, 10, and 15 days following this treatment, blood was collected, colonoscopy was performed, and rectal tissue was harvested for histologic examination.

RESULTS

Mitomycin C suppository was significantly less toxic compared with intravenous delivery, and higher rectal tissue concentrations were observed from 10 to 30 minutes (P < 0.05). Compared with intravenous 5-fluorouracil administration and radiation, 5-fluorouracil suppository and radiation resulted in additive myelosuppression at day 6 (P < 0.05) with rapid recovery.

CONCLUSIONS

5-Fluorouracil and mitomycin C suppository delivery combined with radiation causes less systemic toxicity and is more effective than intravenous administration.

Absorbable, delayed-release antibiotic beads reduce surgical wound infection

Absorbable, polyglycolic acid (PGA) beads were evaluated as a new vehicle for local antibiotic delivery. Incisions on the dorsa of guinea pigs were contaminated with 1 x 10(8) Escherichia coli and 1 x 10(8) Staphylococcus aureus. PGA beads containing either minocycline, amikacin, or no antibiotic (placebo) were placed into these wounds and compared to animals treated with systemic minocycline or amikacin alone. The diameter of wound erythema was measured daily for 7 days. Serial blood and wound quantitative cultures were obtained, and serum and wound antibiotic concentrations were determined. Both minocycline-PGA and amikacin-PGA-treated wounds exhibited less erythema than placebo-PGA wounds (P < 0.05). All minocycline-PGA and amikacin-PGA-treated wounds healed primarily, whereas 67 per cent of placebo-PGA wounds developed purulence, dehisced, and healed secondarily. Local antibiotic delivery was more effective than systemic administration in reducing wound erythema and the number of bacteria in wound quantitative cultures. E. coli and S. aureus were quantitatively reduced (P < 0.05) in wounds of antibiotic PGA-treated animals compared to those in placebo-PGA-treated and systemic minocycline and systemic amikacin-treated animals. Measurable minocycline and amikacin concentrations were present in antibiotic-PGA-treated wounds through day 3, without detectable serum levels. Delayed-release, absorbable, antibiotic-containing PGA beads effectively prevent infection in contaminated wounds and have the advantage of not requiring vehicle removal.

The natural resistance-associated macrophage protein gene is associated with Crohn's disease

BACKGROUND

Identification of the genes causing inflammatory bowel disease (IBD) would enhance the understanding of and the treatment options for this disease. A hyperreactive immune response toward the intestinal flora has been implicated in the pathology of IBD. The natural resistance-associated macrophage protein (NRAMP) gene is believed to regulate macrophage function, especially the ability to fight intracellular pathogens. Genetic differences of NRAMP might, therefore, be associated with IBD.

METHODS

Two DNA markers (D2S434 and D2S1323) near NRAMP were polymerase chain reaction (PCR) amplified and genotyped with DNA from 103 patients with Crohn's disease, 85 patients with ulcerative colitis, and 98 control subjects. Clinical data were obtained for all patients. Comparisons were made by chi-squared analysis. Disease association with significant haplotypes was expressed as odds ratio.

RESULTS

Allele and genotype distributions were similar for both markers among all groups. Haplotype frequencies were different among Crohn's disease and control groups (p = 0.024). Two individual haplotypes of the patients with Crohn's disease were significant compared with control subjects: DA (p = 0.023; odds ratio, 0.5; 95% confidence interval, 0.3 to 0.9) and EA (p = 0.001; odds ratio, 3.5; 95% confidence interval, 1.6 to 3.2). The haplotype distribution was different within three age-of-onset groups of patients with Crohn's disease (p = 0.05).

CONCLUSIONS

This study is the first to report an association between the NRAMP gene and Crohn's disease.

Crohn's disease and ulcerative colitis are associated with the DNA repair gene MLH1

OBJECTIVE

The purpose of this study was to determine whether there is an association between Crohn's disease and ulcerative colitis with MLH1.

SUMMARY BACKGROUND DATA

Identification of genes involved in the etiology of inflammatory bowel disease may lead to the development of markers that objectively can define disease and permit therapy. The treatment of Crohn's disease of the colon and ulcerative colitis also is complicated by difficulties in differentiating the two conditions.

METHODS

The DNA and clinical data were obtained on 126 unrelated individuals (45 Crohn's disease, 36 ulcerative colitis, and 45 control subjects without intestinal disease). Polymerase chain reaction products were analyzed by single-strand conformation polymorphisms (MLH1 exons 9, 11, 14, 15, and 16) and polyacrylamide gel electrophoresis (markers D3S1611 and D3S1768). All comparisons were analyzed by chi square test. The association between single haplotypes and disease was expressed as relative odds.

RESULTS

MLH1 exons 9, 11, 14, and 16 were monomorphic. Two, four, and six alleles were detected in MLH1 exon 15, D3S1611, and D3S1768, respectively. Significant associations were observed for MLH1 exon 15/D3S1611 haplotypes AB (OR = 5.5; p = 0.007) and BA (p = 0.002) with Crohn's disease and for haplotypes AB (OR = 4.0; p = 0.042), BA (p = 0.035), and BC (OR = 6.1; p = 0.016) with ulcerative colitis. Family history of inflammatory bowel disease was associated with D3S1768/D3S1611 (p = 0.05) and MLH1 exon 15/D3S1611 haplotypes (p = 0.03). D3S1611/D3S1768 haplotype CD (OR = 11.3; p = 0.03) was associated with disease, whereas MLH1 exon 15/D3S1611 haplotype AA (OR = 0.25; p = 0.02) was protective. Comparisons of MLH1 exon 15/D3S1611 haplotypes of Crohn's colitis and patients with ulcerative colitis were significant (p = 0.037).

CONCLUSIONS

This study identifies a novel genetic and clinical association between MLH1 and inflammatory bowel disease.

Suppository delivery of 5-fluorouracil in rectal cancer

BACKGROUND

Preoperative radiotherapy with concomitant intravenous 5-fluorouracil (5-FU-i.v.) is effective in shrinking locally advanced rectal cancers and facilitating subsequent surgery. Topical 5-FU application may enhance its radiosensitizing and cytotoxic effects. Suppository and intravenous 5-FU administration were compared with respect to myelo-suppression and tissue concentrations.

METHODS

Rats received 120 mg/kg 5-FU-i.v. or via suppository (5-FU-S). White blood cell count, serum albumin, alkaline phosphatase, creatinine, and aspartate aminotransferase (AST) were determined before and serially after 5-FU administration. In a separate experiment, rats received 5-FU-S or 5-FU-i.v. as already described. Portal and systemic blood, rectal, iliac lymph node, liver, and lung tissue were harvested for high-performance liquid chromatography determination of 5-FU concentrations 30 min, 1, 3, 6, and 12 h after drug administration.

RESULTS

No toxicity was observed in 5-FU-S animals, whereas 63% of 5-FU-IV animals had diarrhea. Weight loss and myelosuppression occurred only in 5-FU-i.v. animals. Rectal drug concentrations were significantly higher in the 5-FU-S animals compared with 5-FU-i.v. animals, 0.5-6 h after drug administration. Blood, liver, and lung 5-FU concentrations with 5-FU-S were comparable to those with 5-FU-i.v.

CONCLUSIONS

5-FU suppositories are associated with fewer systemic side effects and higher rectal 5-FU concentrations than with 5-FU-i.v. administration.

Constituent analysis may permit improved diagnosis of intra-abdominal abscess

BACKGROUND

Intra-abdominal abscesses (IAA) often fail to resolve with intravenous antibiotics alone and frequently require drainage. Diagnosis of IAA in postoperative patients with other likely sources of infection is very difficult.

PATIENTS AND METHODS

In order to characterize IAA and identify parameters that might facilitate diagnosis, we prospectively examined peripheral blood and pus of 15 consecutive patients with IAA and compared them to samples from 34 consecutive patients with soft-tissue abscesses (STA).

RESULTS

Serum interleukin (IL)-10 was elevated in IAA patients, while abnormally detectable serum IL-4 was demonstrated in the pus of both IAA and STA patients. IL-10 in IAA pus was more than 11-fold higher than in STA, whereas IL-4 in pus was similar in both types of abscesses. Both IL-4 and IL-10 were 4- to 10-fold higher in IAA and STA pus than in corresponding patient serum. Serum lysozyme was, however, significantly elevated in all abscess patients.

CONCLUSIONS

The presence of IL-4 and IL-10 may indicate a T-helper 2 lymphocyte response in the etiology of abscess formation and persistence, although precise determination of T-helper 1-related cytokines is needed to verify this. Serum lysozyme and IL-10 may be reliable and relatively inexpensive diagnostic aids.

HPLC analysis of 5-FU and FdUMP in tissue and serum

Tissue and serum concentrations of 5-fluorouracil (5-FU) and 5-fluoro-2'-deoxyuridine 5' monophosphate (FdUMP) can be determined using a simple and sensitive reverse phase HPLC technique. Samples are extracted with ethyl acetate, evaporated to dryness, resuspended in the mobile phase (water/methanol [85:15]), and injected into a C18 muBondapack column (250 mm x 30 mm) with a flow rate of 1 ml/min. Both fluorescence (266 lambda Excitation and 350 lambda Emission) and UV (250 nm) are used for detection. Standard solutions of 5-FU and FdUMP produce a linear relationship (r2 = 0.985) with a detection sensitivity of 50 pg. Recovery following this extraction procedure is 78%. This analytical method is simple and convenient to use for the simultaneous detection of 5-FU and FdUMP.

A surgical subspecialist enhances general surgical operative experience

OBJECTIVE

To examine the impact of a surgical subspecialist on residents' operative experience in a mature general surgery training program.

METHODS

American Board of Surgery operative experience records were used to examine the impact of a surgical subspecialist on surgical training in a stable residency program. Operations performed as surgeon by residents in their chief and junior years were analyzed 4 years before and 4 years after the addition of this subspecialist to the faculty. Hospital admissions for Crohn's disease and ulcerative colitis during these periods were analyzed as well.

RESULTS

There was a statistically significant increase in the number of ileal pouch anal anastomoses, ileostomies, small-bowel resections, partial colectomies, and coloanal anastomoses performed by surgical residents after the addition of a colorectal surgical subspecialist.

CONCLUSIONS

Subspecialty faculty may favorably influence general surgical training by increasing resident operative experience and patient management skills with procedures characteristic of the subspecialty.

Antibiotic penetration of experimental intra-abdominal abscesses

Intra-abdominal abscess is seldom adequately treated by systemic antibiotics alone and often requires surgical or computed tomography-guided drainage for resolution. Abscess penetration of six currently used antibiotics was examined in a murine intra-abdominal abscess model. Ampicillin/sulbactam, cefmetazole, clindamycin, and trospectomycin penetrated intra-abdominal abscesses to a greater degree than cefoxitin and ceftriaxone. Abscess pus antibiotic levels were not significantly higher after multiple doses than after a single dose. Pus antibiotic levels below the MIC90 for Bacteroides and E. coli within intra-abdominal abscess were observed for most antibiotics with the doses used in this study. Selection of antibiotics with a greater ability to penetrate abscess may be important in optimally treating patients with abdominal infection.

Expression of urokinase-type plasminogen activator and plasminogen activator inhibitor in colon disease

Surveillance colonoscopy and biopsy are inaccurate methods of predicting the likelihood of ulcerative colitis patients to develop colon carcinoma. We examined uPA and PAI-1 as potential markers for assessing these patients and those with familial polyposis who are at risk of developing colon cancer. For comparison, biopsies of normal colon and Crohn's disease were evaluated. We examined 77 colonic mucosa specimens taken from patients undergoing elective resection for benign and malignant colonic disease. uPA and PAI-1 were measured using a monoclonal antibody-based ELISA kit (American Diagnostica, Greenwich, CT) and expressed as ng/mg extract protein. Intra- and interassay controls of uPA gave CV = 3-4% and CV = 8-9%, respectively, while those for PAI-1 were 6-7% and 10-11%, respectively. The Mann-Whitney test showed that both uPA and PAI-1 expression were significantly higher in colon cancer, chronic ulcerative colitis, and Crohn's disease than in normal colon. uPA in familial polyposis samples was similar to that of normal colon, while PAI-1 was much lower than in normal colon. Neither patient age nor sex appeared to influence the expression of these potential markers in any tissue. The pattern of uPA and PAI-1 expression in normal, benign and malignant colon suggests these proteins deserve further consideration as markers for assessing colon carcinoma risk.

Peer review is an effective screening process to evaluate medical manuscripts

OBJECTIVE

To measure the effectiveness of peer review as a screening process to evaluate medical manuscripts.

DESIGN

Retrospective.

SETTING

The editorial office of the American Journal of Surgery (AJS).

METHOD

A MEDLINE search was conducted of publications from 1984 to 1992 for manuscripts that were identical or similar to those rejected by AJS between January and December 1989. Manuscripts that were submitted to AJS by foreign authors were excluded because of the presumed difficulty in tracking foreign-language publications.

MAIN OUTCOME MEASURES

The percentage of manuscripts rejected by AJS that were subsequently published in journals indexed by MEDLINE, the time from rejection to ultimate publication, and the journal of publication. The reasons for rejection were also documented. We assumed that the majority of rejected manuscripts would be published within 3 years after rejection.

RESULTS

One hundred twenty-five manuscripts submitted by North American authors were rejected by AJS in 1989, and 62% were not subsequently published in another core medical journal during the study period. The average duration between rejection and later publication was 17 months. Of those manuscripts subsequently published, 54% appeared in general surgical journals, including 12% that were revised, reevaluated, and later accepted by AJS. Twenty-nine percent of the rejected manuscripts were published in specialty medical journals, 10% in state and local journals, and the remainder in general medical journals. Twenty-eight percent of the authors of rejected manuscripts had previously and subsequently published manuscripts on very similar subjects.

CONCLUSIONS

Our data indicate that the review process serves as a sieve and influences whether manuscripts are published in core medical journals. This was demonstrated by the fact that rejected manuscripts often were not published in other indexed medical journals.

Immunoscintigraphy with 111In-satumomab pendetide in patients with colorectal adenocarcinoma: performance and impact on clinical management

PURPOSE

The role of immunoscintigraphy with 111In-satumomab pendetide in the medical and/or surgical management of colorectal cancer patients was evaluated in a multicenter trial.

METHODS

This 103 patient study population included 46 individuals with rising serum carcinoembryonic antigen levels and otherwise negative diagnostic evaluation, 29 patients with known recurrence, presumed to be isolated and resectable, and 28 patients for whom standard diagnostic tests provided equivocal information.

RESULTS

No adverse reactions were noted following intravenous administration of 1 mg of satumomab pendetide radiolabeled with approximately 5 mCi of 111In. Thirty percent of patients developed human anti-mouse antibodies postinfusion. In the 84 patients for whom correlation with histopathologic, diagnostic, and/or clinical findings was available, antibody imaging demonstrated a sensitivity of 73 percent in patients with confirmed tumor (36/49) and negative results for all 35 patients with no evidence of malignancy. Occult disease was detected in 18 patients.

CONCLUSION

111In-satumomab pendetide immunoscintigraphy was helpful in the medical and/or surgical management of 45 (44 percent) patients and provided information unavailable from other diagnostic modalities.

The two-edged sword of large-dose steroids for spinal cord trauma

OBJECTIVE

In 1990, large-dose steroid administration was advocated in spine-injured patients to lessen neurologic deficits. The authors undertook both prospective and retrospective studies to evaluate the response of such profound pharmacologic intervention.

SUMMARY BACKGROUND DATA

Of all sources of nonfatal injury, spinal cord trauma remains the most devastating in both cost and impact on the quality of the patient's life. One study found that routine large-dose steroid administration after injury lessened the extent of neurologic injury. After uncommonly prompt and broad lay press publicity, this practice was widely accepted. Biased by knowledge of the known immunosuppressive effects of steroids, the authors suspected that pneumonia was both more frequent and severe in steroid-treated patients.

METHODS

Thirty-two patients with cervical or upper thoracic spinal injuries (C3-6, 20 patients; C6-7, 6 patients; and T1-6, 6 patients) were studied at an urban level I trauma center from January 1987 to February 1993. Complete spinal cord injury was present in 22 of 32 patients; 14 patients received steroids postinjury. There was no difference in mean age, cord level, age-adjusted injury severity score, or the percent of injury severity score caused by the spinal injury.

RESULTS

The length of hospital stay was longer in steroid-treated patients (S) than in nonsteroid (NS) patients, that is, 44.4 days versus 27.7 days, respectively (p = 0.065). Seventy-nine per cent of S patients had pneumonia compared with 50% of NS patients (p = 0.614). There was no statistical difference in the episodes of pneumonia per patient between the two groups (p > 0.05). Prospectively, the authors evaluated sequentially several parameters known to be important in human immune responses to bacterial challenges in nine S and five NS patients. In S patients, both the per cent and density of monocyte class II antigen expression and T-helper/suppressor cell ratios were lower than in NS patients. However, S patients did have an initially higher, earlier boost in some host defense parameters that rapidly declined, and their subsequent response was both blunted and delayed. These differences became even clearer when stratified according to cord level and incomplete versus complete cord status. Not surprisingly, infected patients, whether S or NS, had lower levels of monocyte antigen expression, CR3, and helper/suppressor ratios.

CONCLUSIONS

These data do not permit a judgment to be made whether neurologic status was improved by S administration. It is known that vital immune responses were adversely affected, that pneumonia was somewhat more prevalent, and that hospitalization was prolonged and costs therefore increased by an average of $51,504 per admission. Further clinical studies will be needed to determine to what extent these observations offset the putative benefits of large-dose steroids in the treatment of spinal trauma.