Dangers associated with endoscopic management of strictures in IBD.
Explore the source record for details and available documents.
Catheterization↗
Biomedical subjects
Walter A Koltun
Publications and source records attributed to Walter A Koltun.
Enhanced intestinal expression of the proteasome subunit low molecular mass polypeptide 2 in patients with inflammatory bowel disease.
PURPOSE: Low molecular mass polypeptide 2 is an inducible immunoproteasome subunit. The expression of low molecular mass polypeptide 2 has not been examined in the intestine of patients with inflammatory bowel disease. This study was designed to determine whether the intestinal expression of low molecular mass polypeptide 2 was enhanced in a group of patients with inflammatory bowel disease compared with a group of control patients without inflammatory bowel disease. Moreover, we examined the association between low molecular mass polypeptide 2 expression and histologic pathology in these patients. METHODS: Twenty-one patients participated in the study. These included six control subjects without inflammatory bowel disease, eight patients with ulcerative colitis, and seven patients with Crohn's disease. Intestinal low molecular mass polypeptide 2 expression was evaluated by immunohistochemistry, as well as by Western blot. Histology scores (0-40 severity scale) were determined on the same sections of intestine as those used for low molecular mass polypeptide 2 histochemistry. RESULTS: By immunohistochemistry, low molecular mass polypeptide 2 expression was significantly enhanced (P < 0.05 vs. control subjects) throughout visibly diseased areas of colon, rectum, and ileum from patients with inflammatory bowel disease. Low molecular mass polypeptide 2 expression also was increased in macroscopically normal intestine from patients with inflammatory bowel disease compared with normal tissue from control subjects. There was a significant correlation (P < 0.0001) between low molecular mass polypeptide 2 expression and histologic pathology in our patients. Western blot results confirmed that low molecular mass polypeptide 2 expression was enhanced in patients with ulcerative colitis (3.1-fold) and in patients with Crohn's disease (3.5-fold). CONCLUSIONS: Intestinal low molecular mass polypeptide 2 expression is significantly increased in inflammatory bowel disease. The association between intestinal low molecular mass polypeptide 2 expression and histologic pathology suggests that this proteasome subunit plays a role in the pathogenesis of inflammatory bowel disease.
Adult↗
Dextran sulfate sodium-induced colitis is associated with enhanced low molecular mass polypeptide 2 (LMP2) expression and is attenuated in LMP2 knockout mice.
Low molecular mass polypeptide 2 (LMP2) is an inducible proteasome subunit. Our goals were to examine LMP2 expression in mice with dextran sulfate sodium (DSS)-induced colitis and to evaluate colitis in LMP2 knockout (LMP2-/-) mice. Mice were given 2.5% DSS in the drinking water. On day 0, 2, 4, or 6 after DSS treatment, LMP2 expression was determined in the distal colon by western blot and immunohistochemistry. Parameters of colitis were measured in LMP2-/- mice or wild-type mice. LMP2 expression was enhanced in the colon of DSS-treated mice at all time points. Symptoms of DSS-induced colitis were always lower in LMP2-/- mice. Normalized histology scores and colonic IL-1ss levels increased over the 6-day study period in wild-type mice. These parameters were significantly reduced in LMP2-/- mice that consumed DSS for 6 days. Enhanced LMP2 expression contributes to the pathogenesis of DSS-induced colitis in mice.
Animals↗
Modified two-stage ileal pouch-anal anastomosis: equivalent outcomes with less resource utilization.
PURPOSE: A three-stage operative approach to ileal pouch-anal anastomosis is usually undertaken in patients presenting with severe colitis. Increasingly, however, we have performed a two-stage modified ileal pouch-anal anastomosis (colectomy followed by ileal pouch-anal anastomosis without ileostomy). The present study sought to evaluate the safety, results, cost, and length of hospital stay using this modified approach compared to that of the traditional three-stage ileal pouch-anal anastomosis. METHODS: Clinical and financial data were gathered by retrospective review of patients undergoing ileal pouch-anal anastomosis at our institution since 1995. Complications were defined as any event prolonging hospitalization or requiring readmission and were included in the analysis up to six months after final surgery. Functional performance was assessed as of the last clinic visit. Data were compared with Student's t-test and chi-squared analysis. Multivariate analysis was also used to assess risk factors. RESULTS: A total of 23 patients who underwent the two-stage modified procedure and 31 patients who had the three-stage procedure were identified. The two groups were found to be statistically comparable in terms of patient age, gender, duration of illness, and preoperative hematocrit. Follow-up was shorter in the modified group because of its more recent introduction (9.7 months vs. 30.5 months mean follow-up). Ninety-five percent of patients were on immunosuppressive medication before colectomy, but all were off it before the reconstruction. clinical outcomes after ileal pouch-anal anastomosis were equivalent in terms of the number of bowel movements, prevalence of fecal incontinence, and the use of hypomotility medications. No patients with the two-stage modified procedure had anastomotic complications requiring stoma creation. One patient in the three-stage group required re-creation of a stoma after stoma closure for perianal complications suggesting Crohn's disease. Total hospital cost was significantly less in the modified group: USD $27,270 vs. $38,184 (P = 0.0119). Length of stay was also shorter in the two-stage modified group although missing absolute statistical significance (21.0 days vs. 26.0 days, P = 0.0882). CONCLUSIONS: Interval ileal pouch-anal anastomosis reconstruction without a stoma (two-stage modified procedure) after colectomy is functionally equivalent to the traditional three-stage protocol in terms of clinical outcome. However, it has the advantage of overall lower hospital costs and probably a shorter length of hospital stay.
Adult↗
Intravenous cyclosporine for the treatment of severe steroid refractory ulcerative colitis: what is the cost?
PURPOSE: Intravenous cyclosporine often is used to treat patients with severe steroid refractory colitis secondary to ulcerative colitis in an attempt to avoid urgent total abdominal colectomy. The purpose of this study was to evaluate the success and cost of cyclosporine. METHODS: A retrospective, chart review of all patients from 1996 to 2002 who were treated with cyclosporine and/or had a three-stage ileal pouch-anal anastomosis for severe steroid refractory colitis at our institution was performed. Patients were divided into three groups: TAC and CyA: patients who failed cyclosporine and had urgent total abdominal colectomy on the same admission; TAC no CyA: patients who had an urgent total abdominal colectomy without cyclosporine; and CyA only: patients treated successfully with cyclosporine and discharged without surgery. A subgroup of patients who had an ileal pouch-anal anastomosis was identified from each group. Cost data were obtained from the hospital's financial records. RESULTS: Forty-one patients (25 males) were identified. Twenty-nine patients received cyclosporine for severe steroid refractory colitis. Of these, 18 (62 percent) failed and underwent total abdominal colectomy on the same admission. Eleven (38 percent) responded to the cyclosporine and were discharged. Of the 11, 4 never had surgery, 1 had a three-stage ileal pouch-anal anastomosis, 5 had a two-stage ileal pouch-anal anastomosis, and 1 had a total abdominal colectomy only. Only 14 percent of patients avoided colectomy in the long-term. Complications of cyclosporine occurred in 8 patients (28 percent), and surgical complications occurred in 12 patients. CONCLUSIONS: The highest costs, highest length of stay, and highest number of overall complications were found in the group of patients who failed intravenous cyclosporine and required colectomy during the same hospitalization.
Adult↗
Stat6(null phenotype) human lymphocytes exhibit increased apoptosis.
BACKGROUND: Inflammatory bowel disease (IBD) is associated with altered apoptosis and increased levels of Th1 cytokines (IL-12, TNF-alpha, and IFN-gamma). These proinflammatory events may result from dysfunctional IL-4/Stat6 signal transduction that normally promotes Th2 lymphocyte differentiation and consequential down-regulation of the immune response. The goal of the present study was to measure apoptosis, levels of relevant cytokines, and the effects of cytokine manipulation on apoptosis in cell lines derived from IBD patients that express dysfunctional Stat6 (Stat6(null phenotype)) and wild-type Stat6 (Stat6(high phenotype)). MATERIALS AND METHODS: Lymphocytes with Stat6(null phenotype) (n = 5) or wild-type (n = 5) status were cultured with and without the addition of exogenous cytokines or neutralizing antibodies (IL-12, TNF-alpha, and IFN-gamma). Apoptosis was determined by flow cytometry using Annexin V-PE dual staining. Cytokine levels were determined by ELISA. RESULTS: Stat6(null phenotype) cells exhibited increased apoptosis compared with wild-type cell lines (13.3% +/- 2.9 versus 4.5% +/- 0.4, P < 0.0001). Four of five Stat6(null phenotype) cell lines expressed 5- to 10-fold elevations in IL-12 and IFN-gamma. Addition of exogenous cytokines or neutralizing antibodies had no effect on apoptosis. CONCLUSIONS: Apoptotic cell death is elevated in Stat6(null phenotype) cell lines suggesting a role for Stat6 in apoptosis regulation, a previously unrecognized observation. Increased levels of IL-12 and IFN-gamma were found in the Stat6(null phenotype) cell lines; however, the apoptosis observed is not the consequence of increased IL-12, IFN-gamma, or TNF-alpha. Stat6(null phenotype) cell lines exhibit variably increased levels of these Th1 cytokines, consistent with their human source, and may be a valid source for investigations into IBD pathophysiology.
Antibodies↗
Tumor necrosis factor alpha disrupts tight junction assembly.
BACKGROUND: We have previously shown an increase in intestinal permeability and a corresponding decrease in the expression of tight junction (TJ) proteins in the in testines of patients with Crohn's disease (CD). Tumor necrosis factor-alpha (TNFalpha) has been implicated in the inflammatory process of CD and its suppression has therapeutic benefit. ZO-1, occludin, and the claudins are key proteins in the TJ. HYPOTHESIS: TNFalpha disrupts the TJ. METHODS: MDCK cells were incubated with TNFalpha (0-100 ng/ml) for 5 days. Qualitative evaluation of the TJ was done with monoclonal antibody to ZO-1 detected by an immunofluorescence. Duplicate cells were lysed and ZO-1, occludin, and claudin-1 amount determined by western blot. RESULTS: Immunofluorescent staining of MDCK cells for ZO-1 showed TJ structural disruption with increasing amount of TNFalpha characterized by fragmented staining of ZO-1. There were no significant differences in quantitation of ZO-1 or occludin in the MDCK cells for all TNFalpha concentrations. There was a significant decrease in the amount of claudin-1 with increasing concentration of TNFalpha. CONCLUSIONS: (1) MDCK TJs are qualitatively disrupted by TNFalpha. (2) This disruption is not because of a decrease in cell number, lack of cell layer confluency, or a decrease in the amount of ZO-1 or occludin. (3) The amount of claudin-1 present in the cell is decreased with increasing amounts of TNFalpha suggesting that the lack of claudin-1 may cause a relocation of ZO-1 away from the TJ. (4) This rearrangement may play a role in the increased intestinal permeability seen in CD and other diseases.
Animals↗
Human B lymphoblast cell lines defective of Stat6 signaling produce high levels of proinflammatory cytokines IL-12, TNFalpha and IFNgamma.
Based on Stat6 gene knockout animal models, the Stat6 signaling pathway has been suggested to play a role in carcinogenesis and Th1/Th2 cytokine balance. Using a semiquantitative EMSA assay and EBV-transformed human B lymphoblast cell lines, we have previously identified three Stat6 activational phenotypes, termed as Stat6high, Stat6low, and Stat6null. A genetic mechanism has been proposed which determines the IL-4-induced activation of the human Stat6 signaling. With respect to the contribution of variant phenotypes to human disease, we further hypothesize that the Stat6null phenotype may result from a partial defect in Stat6 signaling which resembles Stat6 knockout animals in several functional aspects. The characterization of the human Stat6null phenotype stably displayed by the EBV-B cell lines is easily assailable and possesses important implications with respect to Th1/Th2 cytokine imbalance in diseases such as cancer development/metastasis and inflammatory diseases. In this study, we have extended our investigation to the downstream regulatory consequences associated with these Stat6 phenotypes. Production of three important proinflammatory cytokines, IL-12, TNFalpha and IFNgamma was examined in spontaneous EBV-B cell culture using ELISA methodology. Individual cell lines defined as Stat6null produced significantly higher levels of IL-12, TNFalpha and IFNgamma on day 4 in spontaneous culture in comparison with cell lines characterized as Stat6high and Stat6low. These observations of the human Stat6null phenotype, together with those accruing from Stat6 knockout mouse model studies, suggest that the Stat6 signaling pathway may play a role in maintaining the Th1/Th2 cytokine balance by directly and indirectly down-regulating the production of proinflammatory cytokines, a regulatory process which appears to go awry in inflammatory diseases. Moreover, observations from signal transduction studies in our human B lymphocyte model may be compatible with those in the chosen mouse B lymphocyte for establishing signaling networks by the Alliance for Cellular Signaling (AfCS).
Animals↗
CD1d-expressing dendritic cells but not thymic epithelial cells can mediate negative selection of NKT cells.
Natural killer T (NKT) cells are a unique immunoregulatory T cell population that is positively selected by CD1d-expressing thymocytes. Previous studies have shown that NKT cells exhibit autoreactivity, which raises the question of whether they are subject to negative selection. Here, we report that the addition of agonist glycolipid alpha-galactosylceramide (alpha-GalCer) to a fetal thymic organ culture (FTOC) induces a dose-dependent disappearance of NKT cells, suggesting that NKT cells are susceptible to negative selection. Overexpression of CD1d in transgenic (Tg) mice results in reduced numbers of NKT cells, and the residual NKT cells in CD1d-Tg mice exhibit both an altered Vbeta usage and a reduced sensitivity to antigen. Furthermore, bone marrow (BM) chimeras between Tg and WT mice reveal that CD1d-expressing BM-derived dendritic cells, but not thymic epithelial cells, mediate the efficient negative selection of NKT cells. Thus, our data suggest that NKT cells developmentally undergo negative selection when engaged by high-avidity antigen or abundant self-antigen.
Animals↗
Surgical management of ulcerative colitis in the presence of primary sclerosing cholangitis.
INTRODUCTION: The surgical management of ulcerative colitis in the patient with primary sclerosing cholangitis is controversial. METHODS: This study was designed as a retrospective chart review of all patients with primary sclerosing cholangitis who were surgically treated for ulcerative colitis. RESULTS: Sixteen patients with primary sclerosing cholangitis and ulcerative colitis were identified. The indication for ulcerative colitis surgery was dysplasia in 7 patients (44 percent), cancer in 2 (13 percent), intractability in 4 (25 percent), and unknown in 1. Final colon pathology demonstrated cancer in three patients and dysplasia in four. Two patients had biliary cancer discovered at the time of orthotopic liver transplantation. Thirteen patients were known to have primary sclerosing cholangitis when they underwent surgery for ulcerative colitis; two patients with severe primary sclerosing cholangitis underwent simultaneous orthotopic liver transplantation/total abdominal colectomy and did well with subsequent ileal pouch reconstruction. Two patients had orthotopic liver transplantation first and then ileal pouch-anal anastomosis (1 patient) or total abdominal colectomy (1 patient) and did well. Seven patients had well-controlled primary sclerosing cholangitis on medication and underwent ileal pouch-anal anastomosis or total abdominal proctocolectomy without significant hepatic compromise. One patient with moderate primary sclerosing cholangitis underwent ileorectal anastomosis and had severe liver failure postoperatively but survived. Another patient with worsening primary sclerosing cholangitis after total abdominal colectomy has since developed persistent bleeding from peristomal varices. CONCLUSIONS: The overall cancer/premalignant lesion rate was high (50 percent in this study) in patients with primary sclerosing cholangitis and ulcerative colitis. Complications associated with the surgical management of ulcerative colitis are largely dictated by the degree of liver disease present at the time of surgery. Patients with significant primary sclerosing cholangitis that requires colectomy can undergo simultaneous orthotopic liver transplantation/total abdominal colectomy and then be candidates for subsequent ileal pouch-anal anastomosis reconstruction once liver function has improved. Patients with well-controlled primary sclerosing cholangitis can undergo ileal pouch-anal anastomosis surgery safely.
Adult↗
Factors affecting cost and length of stay associated with the ileal pouch-anal anastomosis.
PURPOSE: The purpose of this study was to evaluate the costs associated with the ileal pouch-anal anastomosis procedure and identify those factors that most affected or determined such costs. Specifically evaluated were the costs, complication rates, and length of stay associated with the ileal pouch-anal anastomosis done as a one-stage, two-stage, two-stage modified, or three-stage procedure. METHODS: Costs from the hospital accounting database and clinical data from retrospective chart review of 135 ileal pouch-anal anastomosis patients from a ten-year period were compiled. Overall costs and length of stay (the sum of all hospitalizations for all surgeries and any related complications) for each group were compared by analysis of variance. Linear regression was used to compute net costs and length of stay excluding contributions from other relevant factors such as number of operative stages, complications, demographics, and nonelective operations. RESULTS: The average overall cost and length of stay of the ileal pouch-anal anastomosis ranged from a low of $12,738 and 13.5 days for the one-stage procedure to a high of $32,758 and 23.9 days for the three-stage pathway. Overall costs, length of stay, and incidence of complications increased with the number of operations necessary to complete the ileal pouch-anal anastomosis. This pattern of increased costs and length of stay with the greater number of stages persisted even after demographic and preoperative characteristics were controlled for in the analyses. The occurrence of a complication added an average of $9,304 (P < 0.0001) and 7.4 days to the procedure (P = 0.0002), whereas an urgent presentation added an average of $5,258 (P = 0.15) and 6.1 days (P = 0.04). CONCLUSIONS: The two most definitive determinants of cost and length of stay after ileal pouch-anal anastomosis are complications and number of operative stages used to complete the operation. Elective ileal pouch-anal anastomosis operations done in the fewest stages with the least complications provide the least costly result and the shortest hospital stay. For patients with severe disease, the two-stage modified pathway (total abdominal colectomy followed by pouch creation without a protecting ileostomy) appears to have fewer complications, lower costs, and a shorter length of stay than the traditional three-stage pathway.
Adult↗
Genetic control of interleukin-4-induced activation of the human signal transducer and activator of transcription 6 signaling pathway.
The interleukin (IL)-4-induced Stat6 signaling pathway is active in a variety of cell types, including immune cells and cancer cells, and plays an important role in the regulation of gene expression, such as CD23 and major histocompatibility complex class II. Using a semiquantitative gel shift assay in which nuclear Stat6 activities were scored, three Stat6 activation phenotypes were defined as Stat6(high) (intense banding), Stat6(low) (medium intensity banding), and Stat6(null) (very low to no discernible banding). These Stat6 phenotypes correlated well with levels of CD23 expression, but not with those of human leukocyte antigen-DR cell-surface display. Pedigree analyses revealed a Mendelian inheritance pattern that can be explained by two STAT6 Pathway (STAT6P) activation genotypes, which we term A and a, where STAT6P*A determines an active Stat6 signaling and STAT6P*a determines an inactive Stat6 signaling, with incomplete dominance. Total Stat6 protein levels failed to correlate with the above Stat6 phenotypes allowing us to propose that IL-4-induced Stat6 signaling is a polygenic quantitative trait regulated by a collection of several contributing genetic loci that functionally interact. The Stat6(null) phenotype may result from a defect in Stat6 signaling, which has important implications with respect to the pathogenesis of cancer and Th1/Th2 cytokine imbalance in autoimmune diseases in general.
Cell Line, Transformed↗
Remicade does not abolish the need for surgery in fistulizing Crohn's disease.
PURPOSE: Tumor necrosis factor antagonist therapy in the form of infliximab has been shown to promote significant healing in fistulizing Crohn's disease and therefore is often considered as a possible alternative to surgery. Our aim was to evaluate the role of infliximab in supplanting surgery for fistulizing Crohn's disease. METHODS: We performed a retrospective chart review of all adult patients who received infliximab for fistulizing Crohn's disease at one institution between September 1998 and October 2000. RESULTS: Twenty-six patients (14 male; mean age, 38 years; range, 19-80 years) received a mean of three (range, one to six) doses of infliximab (5 mg/kg) with the intent to cure fistulizing Crohn's disease. Nine patients (35 percent) had perianal, 6 (23 percent) enterocutaneous, 3 (12 percent) rectovaginal, 4 (15 percent) peristomal, and 4 (15 percent) intra-abdominal fistulas. Nineteen (73 percent) of the patients had had prior surgery for Crohn' s disease. Six patients (23 percent) had a complete response to infliximab with fistula closure, 12 (46 percent) had a partial response, and 8 (31 percent) had no response to infliximab. Fourteen (54 percent) patients still required surgery for their fistulizing Crohn's disease after infliximab therapy (10 bowel resections, 4 perianal procedures), whereas half (6/12) of the patients treated with infliximab who still had open fistulas after treatment declined surgical intervention. Five of six patients with fistula closure on infliximab had perianal or rectovaginal fistulas. None of the patients with either enterocutaneous or peristomal fistulas were healed with infliximab. CONCLUSIONS: Although it was associated with a 61 percent complete or partial response rate, infliximab therapy did not supplant the need for surgical intervention in the majority of our patients with fistulizing Crohn's disease. Seventy-three percent of the patients either required surgery or still had open fistulas after infliximab therapy. Infliximab was much more effective in treating perianal disease than abdominal enterocutaneous disease.
Adult↗
Hospital costs and risk factors associated with complications of the ileal pouch anal anastomosis.
BACKGROUND: The purpose of this study was to estimate the costs associated with the most common complications of the ileal pouch anal anastomosis (IPAA) and identify factors that predispose to them. METHODS: Hospital costs of 135 patients undergoing the IPAA were combined with information abstracted from charts. Logistic and linear regression modeling were used to estimate the marginal costs for the most common IPAA complications and determine factors predisposing to their occurrence. RESULTS: The average overall cost for the IPAA was $20,865. Just more than half (53%) of patients experienced complications, the 3 most common being small-bowel obstruction (24.4%), pelvic/abdominal sepsis (6.7%), and dehydration (5.9%). The average cost to treat an episode of small-bowel obstruction was $6709. Treatment of pelvic/abdominal sepsis averaged $9268 per occurrence, whereas dehydration averaged $4860. Steroid use > 3 months before colectomy significantly increased the risk for any complication (P =.02). No factors were found to be good predictors of bowel obstruction. However, age > 42 years and low patient hematocrit were significant predictors of dehydration as a complication (P <.05). Trending toward significance were urgent operation and weight loss greater than 5%. CONCLUSIONS: The most common complications of the IPAA are small-bowel obstruction, pelvic/abdominal sepsis, and dehydration. Complications were responsible for approximately 44% of the overall cost of an IPAA. Factors that increase risk of IPAA complications are steroid use, low hematocrit, age > 42 years, nonelective procedures, and preoperative weight loss.
Adult↗
Factors affecting surgical risk in elderly patients with inflammatory bowel disease.
The operative treatment of elderly patients with inflammatory bowel disease (IBD) has often been avoided in favor of medical management because of a perceived increase in surgical risk. This study sought to define the following in the elderly IBD patient population: (1) the risk of surgical management and (2) those factors affecting risk. Thirty patients with IBD, aged 60 years or more, who were surgically managed by a single surgeon over a 10-year period, were retrospectively matched to 75 patients with IBD who were less than 60 years of age; patients were matched according to sex, date of surgery, and type of surgery performed. Regression analysis using generalized estimating equation methodology to account for the matched clusters of patients was performed to evaluate the effect of age group on the complication rate, operating room time, and length of hospital stay. Presence of comorbid conditions, surgical indications, prior surgery for IBD, and the use of immunosuppressive medications were studied in multivariate models, adjusting for age group. By means of univariate analysis, the odds of complications in elderly IBD patients were shown to be statistically higher than the odds seen in younger patients (47% vs. 20%, P = 0.01). Also observed in the elderly group were a longer length of hospital stay (11.5 days vs. 7.1 days, P = 0.001) and longer operating room time (249 minutes vs. 212 minutes, P = 0.02). Multivariate analysis revealed that the effect of age remained statistically significant, even when adjusted for potential confounding variables such as comorbidity, medications, date of diagnosis of IBD, and indications for surgery. The complication outcome was significantly associated with the surgical indication, with obstruction, fistula, and bleeding having increased odds of complications as compared with other indications (odds ratio = 1.7 vs. 4.2 vs. 7.2, respectively, P = 0.02). The length of hospital stay similarly was significantly associated with the surgical indication (fistula, 10.5 days vs. bleeding, 9.8 days vs. obstruction, 7.4 days vs. other, 9.3 days; P = 0.04) and a history of prior surgery. A significant interaction for length of hospital stay was present between age group and prior surgery status (with prior surgery: old, 18 days vs. young, 6.4 days, P = 0.0001; without prior surgery: old, 9.5 days vs. young 7.3 days, P = 0.10). Elderly patients with IBD have an increased rate of postoperative complications along with an increased length of hospital stay and increased operating room time. This effect of age persists when adjusted for comorbidity and immunosuppressive therapy. Complications are most dependent on surgical indications, with obstruction being the least and bleeding the worst predictive factors. The longest hospital stay is associated with patients who require surgery for fistulous disease and patients who have undergone previous surgery. The fact that the higher complication rate seen in older patients with IBD is associated with disease-defined surgical indications suggests that IBD in elderly patients may be more aggressive than what is observed in younger individuals.
Adolescent↗
Phenotyping of IL4-induced nuclear Stat6 activity in humans: quantitation after gel shift assay using immortalized cell lines.
The IL4-induced Stat6 signaling pathway is active in a variety of cell types, including different cancer cells, and plays an important role in the regulation of gene expression, such as CD23. There are large quantitative differences in DNA-binding activity of IL4-induced Stat6, which are useful for phenotyping activated Stat6 in normal and disease status. However, quantitation of activated Stat6 is challenging and a standardized methodology is needed. Here we have developed a semi-quantitative methodology using gel shift assay in which IL4-induced nuclear Stat6 activities are measured in human EBV-transformed lymphoblastoid cell lines. Using a DNA probe with high affinity Stat6-binding N4 motif and a specific antibody to Stat6, autoradiographs of EMSA gels are recorded by a scan imager and OD readings of antibody super-shifted Stat6 complex bands are obtained. OD readings of all test cell lines are referenced to that of a standard cell line placed in every single experiment and an OD ratio is obtained for each test cell, which allows assignment of Stat6 activational phenotypes. Using this methodology, we have been able to define three Stat6 activational phenotypes termed as Stat6high (intense banding), Stat6low (medium intensity banding), and Stat6null (very low to no discernible banding). These Stat6 phenotypes correlate well with levels of CD23 expression, but not with those of HLA-DR. Pedigree analysis has revealed a Mendelian inheritance pattern for Stat6 phenotypes. The methodology is useful in association studies in human cancer and autoimmune diseases. The Stat6null phenotype may result from a defect in Stat6 signaling which has important implications with respect to the pathogenesis of cancer and Th1/Th2 cytokine imbalance in general. In addition, the defective Stat6null lines discovered here may serve as a natural human model for comprehensive study in the same way as a Stat6 knockout null animal model does.
Amino Acid Motifs↗