Sirolimus and intraoperative hyperthermic peritoneal chemoperfusion with mitomycin-C do not impair healing of bowel anastomoses

Surgeons will increasingly have to address the development of gastrointestinal disease in transplant patients or deal with extended bowel resection and bowel anastomosis in advanced cancer patients. Immunosuppressants as well as intraoperative hyperthermic peritoneal chemoperfusion (IHPC) may alter intestinal anastomotic healing. We evaluated the effects of the immunosuppressant sirolimus and of IHPC on healing and stability of bowel anastomoses in pigs. Twenty-four pigs were divided into four groups (SIR: sirolimus was administered orally; IHPC: animals received IHPC with mitomycin-C; COMP: combination of sirolimus and IHPC was administered; CON: sham-treated control group). Animals underwent hand-sutured small bowel and left colon anastomoses and were killed on postoperative day 4. Anastomoses were evaluated by morphometric analysis and immunohistochemistry (IHC) and by measuring the bursting pressure (BP). In all experimental groups (SIR, IHPC, COMP), anastomotic BPs remained unaltered and were not statistically different compared with control (CON). In addition, ileum villous height and colonic crypt depth analysis revealed no significant difference in mucosal thickness, and IHC showed no difference among groups in proliferation, as assessed by the number of KI-67- and bromodeoxyuridine-labeled cells. Immunosuppression with sirolimus as well as IHPC with mitomycin-C do not alter healing of intestinal anastomosis in pigs.

[Computer-aided surgery of the paranasal sinuses and the anterior skull base]

Endoscopic or microscopic surgery for chronic rhinosinusitis with or without nasal polyps is a routine intervention in daily practice. It is often a delicate and difficult minimally invasive intervention in a narrow space, with a tunnel view of 4 mm in the case of endoscopy and frequent bleeding in chronically inflamed tissue. Therefore, orientation in such a "labyrinth" is often difficult. In the case of polyp recurrence or tumors, the normal anatomical landmarks are often missing, which renders orientation even more difficult. In such cases, computer-aided navigation together with images such as those from computed tomography or magnetic resonance imaging can support the surgeon to make the operation more accurate and, in some cases, faster. Computer-aided surgery also has great potential for education.

Otologic manifestations in Samter's syndrome

OBJECTIVE: It was the aim of this study to investigate the prevalence of otologic manifestations in a cohort of Samter's syndrome patients (nasal polyps with chronic rhinosinusitis, aspirin intolerance and asthma). METHODS: We analyzed a retrospective and prospective case review from 1995 to 2005, performed in the otorhinolaryngology outpatient clinic of a tertiary referral center. Ear history, clinical examinations, treatment and outcome were evaluated using office and hospital records in 23 cases. All subjects completed a questionnaire. RESULTS: In 6 cases (26%), otological manifestations with ear pressure and conductive hearing loss occurred during an advanced stage of Samter's syndrome (>5 years after onset of the first nasal symptoms) partially responsive to systemic steroids. CONCLUSION: Recognition of the association between Samter's syndrome and otological disease is important (26% of the cases) because it could also be responsive to systemic steroids which prevent progression to irreversible hearing loss or infectious otomastoiditis.

Insulin-like growth factor I improves aspects of mycophenolate mofetil-impaired anastomotic healing in an experimental model

BACKGROUND: Patients taking immunosuppressants after transplantation may require intestinal surgery. Mycophenolate mofetil (MMF) has been found to impair the healing of colonic anastomoses in rats. This study examined whether insulin-like growth factor (IGF) I prevents MMF impairment of anastomotic healing. METHODS: Sixty-three rats were divided into three groups (MMF, MMF/IGF and control). Animals underwent a sigmoid colon anastomosis with a 6/0 suture, and were killed on days 2, 4 and 6 after surgery. Investigations included bursting pressure measurement, morphometric analysis, and assessment of mucosal proliferation by 5-bromo-2'-deoxyuridine and Ki67 immunohistochemistry of the anastomoses. RESULTS: The leak rate was three of 21, one of 20 and two of 20 in the MMF, MMF/IGF-I and control groups respectively. Anastomotic bursting pressures were significantly lower in the MMF group than in the control group on days 2 and 4, but there was no significant difference by day 6. Values in the MMF/IGF-I and control groups were similar. Colonic crypt depth was significantly reduced in MMF-treated animals on days 2 and 4, but this impairment was attenuated by IGF-I on day 4. Similarly, IGF-I reduced the negative impact of MMF on mucosal proliferation on days 2 and 6. CONCLUSION: Exogenous IGF-I improves some aspects of MMF-impaired anastomotic healing.

Acute lower gastrointestinal hemorrhage: minimally invasive management with microcatheter embolization

PURPOSE: To evaluate the efficacy of superselective embolization therapy in the management of acute lower gastrointestinal (LGI) hemorrhage, including any bleeding distal to the ligament of Treitz. MATERIALS AND METHODS: Between June and August 2007, 20 patients with acute LGI bleeding underwent superselective transcatheter arterial embolization (TAE) at the authors' institution. The bleeding had different causes. All patients were treated with use of microcatheters. The following embolic agents were used: microcoils (n = 16), polyvinyl alcohol (PVA) particles (n = 2), and a combination of microcoils and PVA particles (n = 2). Outcome measures included technical success (complete cessation of bleeding as documented at completion angiography), clinical success (resolution of signs or symptoms of LGI bleeding within 30 days after TAE), and the rate of major and minor complications. RESULTS: The identified bleeding sources were as follows: jejunal branch, branch of middle colic artery, branch of ileocolic artery, ileal branch, branch of left colic artery, branch of sigmoid artery, branch of the superior rectal artery, and branch of the middle rectal artery. Technical success with effective control of active bleeding was achieved in all patients (100%). Clinical success attributed to TAE was documented in 18 of the 20 patients (90%). Major complications included death due to pulmonary embolism, heart infarction, and multiorgan failure in the 3rd week after TAE; a procedure-related colonic infarction occurred in one patient. A minor complication occurred in one patient who developed a groin hematoma. CONCLUSIONS: Superselective embolization may be used for effective, minimally invasive control of acute LGI bleeding.

Soluble TNF-alpha but not transmembrane TNF-alpha sensitizes T cells for enhanced activation-induced cell death

In addition to its proinflammatory effects, TNF-alpha exhibits immunosuppression. Here, we compared the capacities of transmembrane TNF-alpha (tmTNF) and soluble TNF-alpha (sTNF) in regulating expansion of activated T cells by apoptosis. Splenic CD4(+) T cells from wtTNF, TNF-alpha-deficient (TNF(-/-)) and TNF(-/-) mice expressing a non-cleavable mutant tmTNF showed comparable proliferation rates upon TCR-mediated stimulation. Activation-induced cell death (AICD), however, was significantly attenuated in tmTNF and TNF(-/-), compared with wtTNF CD4(+) T cells. Addition of sTNF during initial priming was sufficient to enhance susceptibility to AICD in tmTNF and TNF(-/-) CD4(+) T cells to levels seen in wtTNF CD4(+) T cells, whereas addition of sTNF only during restimulation failed to enhance AICD. sTNF-induced, enhanced susceptibility to AICD was dependent on both TNF receptors. The reduced susceptibility of tmTNF CD4(+) T cells for AICD was also evident in an in vivo model of adoptively transferred CD4(+) T-cell-mediated colonic inflammation. Hence, the presence of sTNF during T-cell priming may represent an important mechanism to sensitize activated T cells for apoptosis, thereby attenuating the extent and duration of T-cell reactivities and subsequent T-cell-mediated, excessive inflammation.

Glycyrrhetinic acid food supplementation lowers serum potassium concentration in chronic hemodialysis patients

Hyperkalemia is a common life-threatening problem in hemodialysis patients. Because glycyrrhetinic acid (GA) inhibits the enzyme 11beta-hydroxy-steroid dehydrogenase II and thereby increases cortisol availability to the colonic mineralocorticoid receptor, it has the potential to lower serum potassium concentrations. To test this, 10 patients in a 6 month prospective, double-blind, placebo-controlled crossover study were given cookies or bread rolls supplemented with glycyrrhetinic acid or placebo. Twenty-four-hour blood pressure measurements were performed at baseline and week 6 and 12 of each treatment period. The ratio of plasma cortisol/cortisone was significantly increased in all patients on GA as compared to baseline or placebo, indicating appropriate enzyme inhibition. Nine of the 10 patients had a persistent decrease in predialysis serum potassium concentration. On GA, mean predialysis serum potassium was significantly lower than at baseline or on placebo. On placebo, serum potassium was significantly elevated above the upper limit of normal in 76% compared to 30% of measurements during GA treatment. Furthermore, on this treatment the frequency of severe hyperkalemia significantly decreased from 9% to 0.6%. No differences were found in parameters reflecting sodium retention. Although these studies show that prolonged GA supplementation persistently lowers serum potassium in dialysis patients, a long-term toxicity study will be mandatory before we recommend the routine use of this treatment.

Obesity and overweight associated with lower rates of colorectal cancer screening in Switzerland

Screening for colorectal cancer (CRC) is associated with reduced CRC mortality, but low screening rates have been reported in several settings. The aim of the study was to assess predictors of low CRC screening in Switzerland. A retrospective cohort of a random sample of 940 patients aged 50-80 years followed for 2 years from four Swiss University primary care settings was used. Patients with illegal residency status and a history of CRC or colorectal polyps were excluded. We abstracted sociodemographic data of patients and physicians, patient health status, and indicators derived from RAND's Quality Assessment Tools from medical charts. We defined CRC screening as colonoscopy in the last 10 years, flexible sigmoidoscopy in the last 5 years, or fecal occult blood testing in the last 2 years. We used bivariate and multivariate logistic regression analyses. Of 940 patients (mean age 63.9 years, 42.7% women), 316 (33.6%) had undergone CRC screening. In multivariate analysis, birthplace in a country outside of Western Europe and North America [odds ratio (OR) 0.65, 95% confidence interval (CI) 0.45-0.97], male sex of the physician in charge (OR 0.67, 95% CI 0.50-0.91), BMI 25.0-29.9 kg/m2 (OR 0.66, CI 0.46-0.96) and at least 30.0 kg/m2 (OR 0.61, CI 0.40-0.90) were associated with lower CRC screening rates. Obesity, overweight, birthplace outside of Western Europe and North America, and male sex of the physician in charge were associated with lower CRC screening rates in Swiss University primary care settings. Physician perception of obesity and its impact on their recommendation for CRC screening might be a target for further research.

The severity of neural invasion is associated with shortened survival in colon cancer

PURPOSE Neural invasion (NI) is a histopathologic feature of colon cancer that receives little consideration. Therefore, we conducted a morphologic and functional characterization of NI in colon cancer. EXPERIMENTAL DESIGN NI was investigated in 673 patients with colon cancer. Localization and severity of NI was determined and related to patient's prognosis and survival. The neuro-affinity of colon cancer cells (HT29, HCT-116, SW620, and DLD-1) was compared with pancreatic cancer (T3M4 and SU86.86) and rectal cancer cells (CMT-93) in the in vitro three-dimensional (3D)-neural-migration assay and analyzed via live-cell imaging. Immunoreactivity of the neuroplasticity marker GAP-43, and the neurotrophic-chemoattractant factors Artemin and nerve growth factor (NGF), was quantified in colon cancer and pancreatic cancer nerves. Dorsal root ganglia of newborn rats were exposed to supernatants of colon cancer, rectal cancer, and pancreatic cancer cells and neurite density was determined. RESULTS NI was detected in 210 of 673 patients (31.2%). Although increasing NI severity scores were associated with a significantly poorer survival, presence of NI was not an independent prognostic factor in colon cancer. In the 3D migration assay, colon cancer and rectal cancer cells showed much less neurite-targeted migration when compared with pancreatic cancer cells. Supernatants of pancreatic cancer and rectal cancer cells induced a much higher neurite density than those of colon cancer cells. Accordingly, NGF, Artemin, and GAP-43 were much more pronounced in nerves in pancreatic cancer than in colon cancer. CONCLUSION NI is not an independent prognostic factor in colon cancer. The lack of a considerable biologic affinity between colon cancer cells and neurons, the low expression profile of colonic nerves for chemoattractant molecules, and the absence of a major neuroplasticity in colon cancer may explain the low prevalence and impact of NI in colon cancer.

Interferon-γ Induces Expression of MHC Class II on Intestinal Epithelial Cells and Protects Mice from Colitis

Immune responses against intestinal microbiota contribute to the pathogenesis of inflammatory bowel diseases (IBD) and involve CD4(+) T cells, which are activated by major histocompatibility complex class II (MHCII) molecules on antigen-presenting cells (APCs). However, it is largely unexplored how inflammation-induced MHCII expression by intestinal epithelial cells (IEC) affects CD4(+) T cell-mediated immunity or tolerance induction in vivo. Here, we investigated how epithelial MHCII expression is induced and how a deficiency in inducible epithelial MHCII expression alters susceptibility to colitis and the outcome of colon-specific immune responses. Colitis was induced in mice that lacked inducible expression of MHCII molecules on all nonhematopoietic cells, or specifically on IECs, by continuous infection with Helicobacter hepaticus and administration of interleukin (IL)-10 receptor-blocking antibodies (anti-IL10R mAb). To assess the role of interferon (IFN)-γ in inducing epithelial MHCII expression, the T cell adoptive transfer model of colitis was used. Abrogation of MHCII expression by nonhematopoietic cells or IECs induces colitis associated with increased colonic frequencies of innate immune cells and expression of proinflammatory cytokines. CD4(+) T-helper type (Th)1 cells - but not group 3 innate lymphoid cells (ILCs) or Th17 cells - are elevated, resulting in an unfavourably altered ratio between CD4(+) T cells and forkhead box P3 (FoxP3)(+) regulatory T (Treg) cells. IFN-γ produced mainly by CD4(+) T cells is required to upregulate MHCII expression by IECs. These results suggest that, in addition to its proinflammatory roles, IFN-γ exerts a critical anti-inflammatory function in the intestine which protects against colitis by inducing MHCII expression on IECs. This may explain the failure of anti-IFN-γ treatment to induce remission in IBD patients, despite the association of elevated IFN-γ and IBD.

An Sp1/Sp3 binding polymorphism confers methylation protection.

Hundreds of genes show aberrant DNA hypermethylation in cancer, yet little is known about the causes of this hypermethylation. We identified RIL as a frequent methylation target in cancer. In search for factors that influence RIL hypermethylation, we found a 12-bp polymorphic sequence around its transcription start site that creates a long allele. Pyrosequencing of homozygous tumors revealed a 2.1-fold higher methylation for the short alleles (P<0.001). Bisulfite sequencing of cancers heterozygous for RIL showed that the short alleles are 3.1-fold more methylated than the long (P<0.001). The comparison of expression levels between unmethylated long and short EBV-transformed cell lines showed no difference in expression in vivo. Electrophorectic mobility shift assay showed that the inserted region of the long allele binds Sp1 and Sp3 transcription factors, a binding that is absent in the short allele. Transient transfection of RIL allele-specific transgenes showed no effects of the additional Sp1 site on transcription early on. However, stable transfection of methylation-seeded constructs showed gradually decreasing transcription levels from the short allele with eventual spreading of de novo methylation. In contrast, the long allele showed stable levels of expression over time as measured by luciferase and approximately 2-3-fold lower levels of methylation by bisulfite sequencing (P<0.001), suggesting that the polymorphic Sp1 site protects against time-dependent silencing. Our finding demonstrates that, in some genes, hypermethylation in cancer is dictated by protein-DNA interactions at the promoters and provides a novel mechanism by which genetic polymorphisms can influence an epigenetic state.

Does colon cancer ever metastasize to bone first? a temporal analysis of colorectal cancer progression.

BACKGROUND: It is well recognized that colorectal cancer does not frequently metastasize to bone. The aim of this retrospective study was to establish whether colorectal cancer ever bypasses other organs and metastasizes directly to bone and whether the presence of lung lesions is superior to liver as a better predictor of the likelihood and timing of bone metastasis. METHODS: We performed a retrospective analysis on patients with a clinical diagnosis of colon cancer referred for staging using whole-body 18F-FDG PET and CT or PET/CT. We combined PET and CT reports from 252 individuals with information concerning patient history, other imaging modalities, and treatments to analyze disease progression. RESULTS: No patient had isolated osseous metastasis at the time of diagnosis, and none developed isolated bone metastasis without other organ involvement during our survey period. It took significantly longer for colorectal cancer patients to develop metastasis to the lungs (23.3 months) or to bone (21.2 months) than to the liver (9.8 months). Conclusion: Metastasis only to bone without other organ involvement in colorectal cancer patients is extremely rare, perhaps more rare than we previously thought. Our findings suggest that resistant metastasis to the lungs predicts potential disease progression to bone in the colorectal cancer population better than liver metastasis does.

Regulation of hepatic cytochrome P450 expression in mice with intestinal or systemic infections of citrobacter rodentium.

We reported previously that infection of C3H/HeOuJ (HeOu) mice with the murine intestinal pathogen Citrobacter rodentium caused a selective modulation of hepatic cytochrome P450 (P450) gene expression in the liver that was independent of the Toll-like receptor 4. However, HeOu mice are much more sensitive to the pathogenic effects of C. rodentium infection, and the P450 down-regulation was associated with significant morbidity in the animals. Here, we report that oral infection of C57BL/6 mice with C. rodentium, which produced only mild clinical signs and symptoms, produced very similar effects on hepatic P450 expression in this strain. As in HeOu mice, CYP4A mRNAs and proteins were among the most sensitive to down-regulation, whereas CYP4F18 was induced. CYP2D9 mRNA was also induced 8- to 9-fold in the C57BL/6 mice. The time course of P450 regulation followed that of colonic inflammation and bacterial colonization, peaking at 7 to 10 days after infection and returning to normal at 15 to 24 days as the infection resolved. These changes also correlated with the time course of significant elevations in the serum of the proinflammatory cytokines interleukin (IL)-6 and tumor necrosis factor-alpha, as well as of interferon-gamma and IL-2, with serum levels of IL-6 being markedly higher than those of the other cytokines. Intraperitoneal administration of C. rodentium produced a rapid down-regulation of P450 enzymes that was quantitatively and qualitatively different from that of oral infection, although CYP2D9 was induced in both models, suggesting that the effects of oral infection on the liver are not due to bacterial translocation.

The development and characterization of two types of chronic responses in irradiated mouse colon

The hypothesis to be tested is that there are two distinct types of chronic responses in irradiated normal tissues, each resulting from damage to different cell populations in the tissue. The first is a sequala of chronic epithelial depletion in which the tissue's integrity cannot be maintained, i.e. a "consequential" chronic response. The other response is due to cell loss in the connective tissue and/or vascular stroma, i.e. a "primary" chronic response. The purpose of this study was to test the hypothesis in the murine colon by first, establishing a model of each chronic response and then, by determining whether the responses differed in timing of expression, histology, and expression of specific collagen types. The model of late damage used was colonic obstructions/strictures induced by a single dose of 27 Gy ("consequential" response) and two equal doses of 14.75 Gy (t = 10 days) ("primary" response). "Consequential" lesions appeared as early as 5 weeks after 27 Gy and were characterized by a deep mucosal ulceration and a thickened fibrotic serosa containing excessive accumulations of collagen types I and III. Both types were commingled in the scar at the base of the ulcer. Fibroblasts were synthesizing pro-collagen types I and III mRNA 10 weeks prior to measurable increases in collagen. A significant decrease in the ratio of collagen types I:III was associated with the "consequential" response at 4-5 months post-irradiation. The "primary" response, on the other hand, did not appear until 40 weeks after the split dose even though the total dose delivered was approximately the same as that for the "consequential" response. The "primary" response was characterized with an intact mucosa and a thickened fibrotic submucosa which contained excessive amounts of only collagen type I. An increased number of fibroblasts were synthesizing pro-collagen type I mRNA nearly 25 weeks before collagen type I levels were increased. The "primary" response lesion had a significantly elevated collagen type I:III ratio at 10-13 months post-irradiation. These data show a clear difference between the two chronic response and suggest that not all chronic responses share a common pathogenesis, but depend on the cell population in the tissue that is damaged. ^

Analyses of pp60$\sp{{\rm c}-src}$ and epidermal growth factor receptor protein tyrosine kinases in a human colon adenocarcinoma cell line following induction of goblet cell-like characteristics by tumor necrosis factor-alpha

Regulation of colonic epithelial cell proliferation and differentiation remains poorly understood due to the inability to design a model system which recapitulates these processes. Currently, properties of "differentiation" are studied in colon adenocarcinoma cell lines which can be induced to express some, but not all of the phenotypes of normal cells. In this thesis, the DiFi human colon adenocarcinoma cell line is utilized as an in vitro model system in which to study mucin production. In response to treatment with tumor necrosis factor-alpha, DiFi cells acquire some properties of mucin-producing goblet cells including altered morphology, increased reactivity to wheat germ agglutinin, and increased mucin production as determined by RNA expression as well as reactivity with the MUC-1 antibodies, HMFG-1 and SM-3. Thus, TNF-treated DiFi cells represent one of the few in vitro systems in which mucin expression can be induced.^ DiFi cells express an activated pp60$\sp{{\rm c}-src},$ as do most colon adenocarcinomas and derived cell lines, as well as an amplified epidermal growth factor (EGF) receptor. To assess potential changes in these enzymes during induction of differentiation characteristics, potential changes in the levels and activities of these enzymes were examined. For pp60$\sp{{\rm c}-src},$ no changes were observed in protein levels, specific activity of the kinase, cellular localization, or phosphorylation pattern as determined by Staphylococcus aureus V8 protease partial proteolytic mapping after induction of goblet cell-like phenotypic changes. These results suggest that pp60$\sp{{\rm c}-src}$ is regulated differentially in goblet cells than in absorptive cells, as down-modulation of pp60$\sp{{\rm c}-src}$ kinase occurs in the latter. Therefore, effects on pp60$\sp{{\rm c}-src}$ may be critical in colon regulation, and may be important in generating the various colonic epithelial cell types.^ In contrast to pp60$\sp{{\rm c}-src},$ EGF receptor tyrosine kinase activity decreased ($<$5-fold) after TNF treatment and at the time in which morphologic changes were observed. Similar decreases in tyrosine phosphorylation of EGF receptor were observed as assessed by immunoblotting with an anti-phosphotyrosine antibody. In addition, ($\sp{125}$I) -EGF cell surface binding was reduced approximately 3-fold following TNF treatment with a concomitant reduction in receptor affinity ($<$2-fold). These results suggest that modulation of EGF receptor may be important in goblet cell differentiation. In contrast, other published studies have demonstrated that increases in EGF receptor mRNA and in ($\sp{125}$I) -EGF binding accompany differentiation toward the absorptive cell phenotype. Therefore, differential regulation of both EGF receptor and pp60$\sp{{\rm c}-src}$ occur along the goblet cell and absorptive cell differentiation pathways. Thus, my results suggest that TNF-treated DiFi cells represent a unique system in which to study distinct patterns of regulation of pp60$\sp{{\rm c}-src}$ and EGF receptor in colonic cells, and to determine if increased MUC-1 expression is an early event in goblet cell differentiation. ^