Influence of TNF gene polymorphisms in Japanese patients with NASH and simple steatosis

BACKGROUND/AIMS: Tumor necrosis factor (TNF) is considered to play a role in the second hit of non-alcoholic steatohepatitis (NASH). To clarify the effects of TNF in NASH we investigated TNF gene polymorphisms that might influence TNF production were investigated. METHODS: We analyzed 102 patients with non-alcoholic fatty liver disease (NAFLD; 36 with simple steatosis and 66 with NASH) and 100 control subjects. The serum level of soluble TNF receptor (sTNFR)-2 was measured. The TNF-alpha promoter region positions -1031, -863, -857, -308, and -238 and the TNF-beta gene Nco1 polymorphism site were investigated. RESULTS: The level of sTNFR-2 was significantly higher in NASH patients than in those with simple steatosis or control subjects. In the analysis of TNF gene polymorphisms, there were no significant deviations between the group of all NAFLD patients and the control subjects. The carrier frequencies of polymorphisms at positions -1031C and -863A were significantly higher in patients with NASH than in those with simple steatosis. In the multivariate analysis, TNF-alpha promoter polymorphisms proved to be significant independent factors distinguishing NASH from simple steatosis. CONCLUSIONS: TNF polymorphisms, which influence TNF production, might be associated with the progression of NAFLD.     

Endoscopic mucosal resection of 161 cases of large sessile or flat colorectal polyps

OBJECTIVE: Large sessile or flat colorectal polyps, which are traditionally treated surgically, may be amenable to endoscopic mucosal resection (EMR), often using a piecemeal method. Appropriate selection of lesions and a careful technique may enhance the efficacy of EMR for polyps >or=20 mm in diameter without compromising safety. The aim of this study was to identify the factors that may be predictive of the risk of polyp recurrence. MATERIAL AND METHODS: A retrospective analysis was conducted on the outcome of 161 polyps >or=20 mm in diameter, treated by piecemeal EMR at a single centre using the "lift and cut" technique. All records were reviewed for polyp size, site, morphology and histology. Polypectomy technique, patient follow-up, polyp recurrence and surgical interventions were also recorded. RESULTS: Over an 8-year period, 161 colonic polyps measuring >or=20 mm were removed by EMR. Follow-up data were available for 149 cases (93%) with a mean polyp diameter of 32.5 mm; the total success rate of endoscopic polyp removal was 95.4%. The number of cases requiring 1, 2, 3, 4 and 6 attempts at EMR was 89 (60%), 36 (24%), 14 (9%), 2 (1.3%) and 1 (0.7%), respectively. Recurrence was significantly related to polyp size (p<0.001). There was no statistically significant relationship between site and recurrence. Seven patients (4.6%) underwent surgical intervention after EMR because of failed clearance. There were no post-EMR perforations and significant bleeding was reported in only two patients (1.7%). CONCLUSIONS: With careful attention to technique, piecemeal EMR is a safe option for the resection of most sessile and flat colorectal polyps >or=20 mm in size. A stricter follow-up may be required for larger lesions because of a higher risk of recurrence.     

Multimodality therapy using brachytherapy for caval tumor of hepatocellular carcinoma

BACKGROUND/AIMS: Hepatocellular carcinoma (HCC) invading the inferior vena cava will expose patients to a risk of sudden death. Effective therapeutic approaches have not been established for caval tumor. This pilot study was conducted to evaluate the feasibility, safety, and clinical efficacy of multimodality therapy using endovascular brachytherapy with iridium-192 for caval tumor. METHODOLOGY: Six consecutive patients underwent endovascular high-dose-rate brachytherapy. An iridium-192 source was placed adjacent to the caval tumor through a vascular sheath introduced via the femoral vein. The total dose of brachytherapy ranged from 10 to 14Gy (5-7Gy per fraction). Hepatic arterial infusion chemotherapy was used in combination in all patients and external-beam radiotherapy was performed in 5 patients. RESULTS: Endovascular brachytherapy was technically successful in all patients. There were no complications related to brachytherapy. The median period of follow-up was 14.5 months (range, 3-29 months). Complete response and partial response were achieved in 2 (33%) and 4 (67%) patients, respectively. The 1- and 2-year survival rates were 50% and 17%, respectively, with a median survival of 14 months. CONCLUSIONS: Multimodality therapy using endovascular brachytherapy was a feasible, safe, and effective treatment for patients with advanced HCC invading the inferior vena cava.     

Assessment of pathophysiology based on the left ventricular shape in five patients with midventricular obstructive hypertrophic cardiomyopathy

OBJECTIVES: The pathophysiology of midventricular obstructive hypertrophic cardiomyopathy (MVO) is unknown. Patients with MVO and MVO-like cardiomyopathy were classified into three groups based on the cardioimaging morphological characteristics of the left ventricle to investigate their complications and treatment. METHODS: Four patients with MVO and one patient with disease-like MVO were admitted in our hospital from 1999 to 2005. Group A consisted of one patient with indications of pressure gradient at mid-ventricle without apical aneurysm, Group B consisted of three patients with indications of pressure gradient and apical aneurysm, and Group C consisted of one patient with hour-glass appearance with apical aneurysm and decreased left ventricular systolic function without pressure gradient. RESULTS: The diagnosis was established during examination for sustained ventricular tachycardia (SVT, three patients), paroxysmal atrial fibrillation (one patient), and coronary artery disease (one patient). Cardiogenic embolization was observed in all cases which originated from atrial fibrillation (one case) and apical aneurysm (two cases). No embolic event occurred in any patient after warfarin therapy. SVT occurred in patients in Groups B and C. SVT refractory to beta-blocker and mexiletine was treated by amiodarone. Apical aneurysmectomy and cryoablation could prevent recurrent SVT with drug resistance. CONCLUSIONS: Four of the five patients with MVO had arrhythmia (atrial fibrillation, SVT) and three had cardiogenic embolization. MVO could be classified into three groups depending on the morphological characteristics and complications. Treatment of MVO should be based on these characteristics.     

Comparative analysis of the fate of donor dendritic cells and B cells and their influence on alloreactive T cell responses under tacrolimus immunosuppression

We have shown that tacrolimus (TAC)-induced liver allograft acceptance is associated with migration and persistence of donor B cells and dendritic cells (DC). To clarify whether these MHC class II+ leukocytes have favorable roles in inducing tolerance, we analyzed recipient T cell reactions after allogeneic B or DC infusion. LEW rat B cells localized exclusively in BN host B cell follicles without any direct contact with host T cells. While few donor DC migrated to T cell areas and marginal zones, they were captured by host APC, suggesting that allogeneic MHC class II+ cells may induce immune reactions via the indirect pathway. Although DC-infused non-immunosuppressed recipients showed enhanced ex vivo anti-donor responses, persistent in vitro donor-specific hyporeactivity was seen equally with donor DC or B cell infusion under TAC. The results indicate that donor MHC class II+ APC are capable of regulating recipient immune reactions under TAC. Possible involvement of the indirect pathway of allorecognition is discussed.     

Optimum two-stage designs in case–control association studies using false discovery rate

Genetic association studies using case–control designs are often done to identify loci associated with disease susceptibility. These studies are often expensive to perform, due to a large number of genetic markers. Several types of two-stage designs are proposed and used from the point of cost effectiveness. We proposed to control the false discovery rate for multiple-testing correction in two-stage designs, using optimal sample sizes and criteria for selecting markers associated with a disease in each stage to minimize the cost of genotyping. The expected power and cost of two-stage designs were compared with those of one-stage designs, under the assumptions that the genetic markers are independent and total sample size is fixed. The results showed that the proposed two-stage procedure usually reduced the cost of genotyping by 40–60%, with a power similar to that of the one-stage designs. In addition, the sample size and selection criteria, which are optimized parameters, are defined as a function of a prior probability that marker–disease association is true. So, the effects of mis-specification of a prior probability on efficiency were also considered.Aya Kuchiba and Noriko Y. Tanaka have contributed equally to this study.     

Regulatory T Cells in Immunologic Self-Tolerance and Autoimmune Disease

Naturally arising CD25⁺CD4⁺ regulatory T cells play key roles in the maintenance of immunologic self-tolerance and negative control of various immune responses. The majority, if not all, of them are produced by the normal thymus as a functionally distinct T-cell subpopulation, and their generation is in part developmentally controlled. Genetic abnormality in the development and function of this population can indeed be a cause of autoimmune disease, immunopathology, and allergy in humans. This regulatory population can be exploited to prevent and treat autoimmune disease by strengthening and reestablishing immunologic self-tolerance.     

Kir6.2-deficient mice are susceptible to stimulated ANP secretion: K(ATP) channel acts as a negative feedback mechanism?

OBJECTIVE: While atrial natriuretic peptide (ANP) has been shown to be released mainly from cardiac muscle cells in response to atrial distension, the regulatory mechanisms of ANP secretion are still not fully understood. We sought to determine whether the ATP-sensitive K+ (K(ATP)) channel modulates the secretion of ANP, using mice with homozygous knockout of the Kir6.2 (a pore-forming subunit of cardiac K(ATP) channel) gene. METHODS: K(ATP) channel currents were recorded from isolated mouse atrial cells with patch-clamp techniques. Plasma ANP concentrations in anesthetized mice and ANP content and secretion in isolated atrial preparations were determined by radioimmunoassay. Action potentials were recorded from the isolated atria. RESULTS: Exposure to 2,4-dinitrophenol (100 microM) evoked a glibenclamide-sensitive K(ATP) channel current in atrial cells from wild-type (WT) but not Kir6.2 knockout (Kir6.2 KO) mice. Although there were no significant differences in the basal plasma ANP levels between WT and Kir6.2 KO mice, volume expansion caused a significant elevation of plasma ANP concentration in Kir6.2 KO but not WT mice with accompanying hypotension. When isolated left atria were stretched, ANP secreted into the bath from Kir6.2 KO atria was significantly higher than that from WT atria. Furthermore, stretching the atria from WT but not Kir6.2 KO mice significantly shortened the action potential duration. A hypotonic stretch of the membrane induced the glibenclamide-sensitive K(ATP) channel current in atrial cells from WT but not Kir6.2 KO mice. CONCLUSIONS: Kir6.2 is essential for the function of K(ATP) channel in mouse atrial cells. Given that Kir6.2 KO mice are susceptible to stretch-induced secretion of ANP, our results suggest that K(ATP) channels may act as a negative feedback mechanism for the control of ANP secretion.