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Strain Type (strain + type)
Selected AbstractsIs the Association Between Helicobacter pylori and Gastric Cancer Confined to CagA-Positive Strains?HELICOBACTER, Issue 3 2004Maria Held ABSTRACT Background., Infection with Helicobacter pylori is associated with an increased risk of gastric cancer. Several studies have indicated that the association differs with strain type. We aimed to find out if infection with strains lacking the virulence factor CagA is linked to gastric cancer risk. Materials and methods., In a hospital-based case,control study, we collected sera from 100 case patients with a newly diagnosed gastric adenocarcinoma and 96 control patients with diseases unrelated to H. pylori status. Antibodies to H. pylori were analyzed by enzyme-linked immunosorbent assay (ELISA), and antibodies to CagA were detected by immunoblot. Logistic regression was used to obtain odds ratios (ORs) as estimates of relative risk, adjusted for potential confounding. Results., Among the case patients, 81% were ELISA positive and 86% had antibodies to CagA. The corresponding numbers among the controls were 58% and 55%, respectively. ELISA positivity was associated with an increased risk of gastric adenocarcinoma compared to ELISA negativity (OR for gastric cancer regardless of site 3.9, 95% CI 1.9,8.2). The OR was 7.4 (95% CI 3.3,16.6) for CagA-positive relative to CagA-negative subjects. Among ELISA-positive subjects the presence of CagA antibodies increased the risk 3.6 times (95% CI 1.2,11.1). ELISA-positive CagA-negative infections were associated with a fourfold increased risk (OR = 4.2, 95% CI 1.0,17.0) compared to no infection (ELISA-negative and CagA-negative). Conclusions., Although patients with antibodies to CagA have the greatest risk of developing gastric cancer, those with CagA-negative infections run a significantly greater risk than uninfected persons. [source] Comparative analysis of NK/T-cell lymphoma and peripheral T-cell lymphoma in Korea: Clinicopathological correlations and analysis of EBV strain type and 30-bp deletion variant LMP1PATHOLOGY INTERNATIONAL, Issue 11 2003Ji Eun Kim Natural killer/T-cell lymphoma (NKTL) and peripheral T-cell lymphomas (PTCL) are prevalent in the Asian population and exhibit a high association with the Epstein,Barr virus (EBV). Moreover, differentiation of these two groups is often difficult and problematic. We investigated 35 cases of NKTL (22 nasal cases and 13 extranasal cases) and 30 cases of PTCL in terms of their clinical features, immunohistology, EBV positivity, EBV strain-type polymorphism and latent membrane protein 1 (LMP1) deletion variant distribution. Eighteen cases (82%) of nasal NKTL and seven (54%) of extranasal NKTL showed EBV positivity by EBV in situ hybridization. Fifteen cases (50%) of PTCL revealed EBV positivity. EBV strain type A was predominant in NKTL (18:5), and EBV strain types A and B were distributed evenly in PTCL (6:6). EBV-positive patients had significantly shorter survival than EBV-negative patients (P < 0.05), and EBV positivity correlated with advanced clinical stage (P < 0.05). Patients harboring type A EBV showed slightly poorer prognoses than those having type B, though it was not obviously statistically different (P = 0.07). The LMP1 deletion variant was prevalent in both NKTL (three wild-type LMP1, 15 deletion variants) and PTCL (three wild-type LMP1, eight deletion variants, two coexistent forms) patients, but did not have prognostic impact. Our results indicate that EBV acts as a negative prognostic factor in NKTL and PTCL, and that the intrinsic properties of a specific viral strain might influence the clinical behavior of these diseases. [source] Modeling and Optimization of Photosynthetic Hydrogen Gas Production by Green Alga Chlamydomonas reinhardtii in Sulfur-Deprived CircumstanceBIOTECHNOLOGY PROGRESS, Issue 2 2006Ji Hye Jo Biological hydrogen production by the green alga Chlamydomonas reinhardtii under sulfur-deprived conditions has attracted great interest due to the fundamental and practical importance of the process. The photosynthetic hydrogen production rate is dependent on various factors such as strain type, nutrient composition, temperature, pH, and light intensity. In this study, physicochemical factors affecting biological hydrogen production by C. reinhardtii were evaluated with response surface methodology (RSM). First, the maximum specific growth rate of the alga associated with simultaneous changes of ammonium, phosphate, and sulfate concentrations in the culture medium were investigated. The optimum conditions were determined as NH4+ 8.00 mM, PO43, 1.11 mM, and SO42, 0.79 mM in Tris-acetate-phosphate (TAP) medium. The maximum specific growth rate with the optimum nutrient concentrations was 0.0373 h,1. Then, the hydrogen production rate of C. reinhardtii under sulfur-deprivation conditions was investigated by simultaneously changing two nutrient concentrations and pH in the medium. The maximum hydrogen production was 2.152 mL of H2 for a 10-mL culture of alga with density of 6 × 106 cells mL,1 for 96 h under conditions of NH4+ 9.20 mM, PO43, 2.09 mM, and pH 7.00. The obtained hydrogen production rate was approximately 1.55 times higher than that with the typical TAP medium under sulfur deficiency. [source] Mouse Strain Susceptibility to Diethylnitrosamine Induced Hepatocarcinogenesis Is Cell Autonomous Whereas Sex-susceptibility Is Due to the Micro-environment: Analysis with C3H , BALB/c Sexually Chimeric MiceCANCER SCIENCE, Issue 7 2000Tetsuya Tsukamoto In man, liver cancer is on the increase, especially in males. Sex differences also exist in rodent models. To elucidate the mechanisms, chimeric mice were produced by amalgamation of early embryos from high and low hepatocarcinogen-susceptible strains, C3H and BALB/c. Tumor formation was initiated with 10 mg/kg of diethylnitrosamine at the ages of 7 and 14 days and mice were sacrificed at 30 and 45 weeks. The chimeras were classified into XY,XY, XY,XX, XX,XY, and XX,XX in terms of sex chromosomes by means of polymerase chain reaction-simple sequence length polymorphism analysis (SSLP) using Y chromosome-specific Sry primers in combination with the D3Mit21 marker. Liver lesions were analyzed histopathologically, by immunostaining using a C3H strain-specific antibody and by DNA in situ hybridization with the Y chromosomespecific digoxigenin-labeled Y353/B probe. Sex and strain genotyping by SSLP analysis matched histological observations, confirming the reliability of our system. The strain differences in liver tumor numbers of each strain type in XY,XY and XX,XX subtypes of C3H,BALB/c chimeras were retained well (P< 0.0001 and P< 0.001, respectively), indicating a minimum influence of the C3H or BALB/c surrounding milieu on development of individual lesions. On the other hand, significant promotion of XX cell tumors was evident in phenotypically male sexually chimeric XY,XX and XX,XY chimeras for both C3H (P< 0.02) and BALB/c (P< 0.01) lesions compared to the XX,XX case. The results suggest the presence of hormonal or micro-environmental factors specific for males, which are not caused cell-autonomously. Basic strain differences, however, are determined by intrinsic genetic factors rather than the strain-dependent micro-environment [source] | ||||||||||