157 research outputs found

    The free energy in the Derrida--Retaux recursive model

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    We are interested in a simple max-type recursive model studied by Derrida and Retaux (2014) in the context of a physics problem, and find a wide range for the exponent in the free energy in the nearly supercritical regime

    Risk of venous thromboembolism after total hip and knee replacement in older adults with comorbidity and co-occurring comorbidities in the Nationwide Inpatient Sample (2003-2006)

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    <p>Abstract</p> <p>Background</p> <p>Venous thromboembolism is a common, fatal, and costly injury which complicates major surgery in older adults. The American College of Chest Physicians recommends high potency prophylaxis regimens for individuals undergoing total hip or knee replacement (THR or TKR), but surgeons are reluctant to prescribe them due to fear of excess bleeding. Identifying a high risk cohort such as older adults with comorbidities and co-occurring comorbidities who might benefit most from high potency prophylaxis would improve how we currently perform preoperative assessment.</p> <p>Methods</p> <p>Using the Nationwide Inpatient Sample, we identified older adults who underwent THR or TKR in the U.S. between 2003 and 2006. Our outcome was VTE, including any pulmonary embolus or deep venous thrombosis. We performed multivariate logistic regression analyses to assess the effects of comorbidities on VTE occurrence. Comorbidities under consideration included coronary artery disease, congestive heart failure (CHF), chronic obstructive pulmonary disease (COPD), diabetes, and cerebrovascular disease. We also examined the impact of co-occurring comorbidities on VTE rates.</p> <p>Results</p> <p>CHF increased odds of VTE in both the THR cohort (OR = 3.08 95% CI 2.05-4.65) and TKR cohort (OR = 2.47 95% CI 1.95-3.14). COPD led to a 50% increase in odds in the TKR cohort (OR = 1.49 95% CI 1.31-1.70). The data did not support synergistic effect of co-occurring comorbidities with respect to VTE occurrence.</p> <p>Conclusions</p> <p>Older adults with CHF undergoing THR or TKR and with COPD undergoing TKR are at increased risk of VTE. If confirmed in other datasets, these older adults may benefit from higher potency prophylaxis.</p

    The association between Toll-like receptor 2 single-nucleotide polymorphisms and hepatocellular carcinoma susceptibility

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    <p>Abstract</p> <p>Background</p> <p>Toll-like receptors (TLR) are key innate immunity receptors participating in an immune response. Growing evidence suggests that mutations of TLR2/TLR9 gene are associated with the progress of cancers. The present study aimed to investigate the temporal relationship of single nucleotide polymorphisms (SNP) of TLR2/TLR9 and the risk of hepatocellular carcinoma (HCC).</p> <p>Methods</p> <p>In this single center-based case-control study, SNaPshot method was used to genotype sequence variants of TLR2 and TLR9 in 211 patients with HCC and 232 subjects as controls.</p> <p>Results</p> <p>Two synonymous SNPs in the exon of TLR2 were closely associated with risk of HCC. Compared with those carrying wild-type homozygous genotypes (T/T), risk of HCC decreased significantly in individuals carrying the heterozygous genotypes (C/T) of the rs3804099 (adjusted odds ratio (OR), 0.493, 95% CI 0.331 - 0.736, <it>P </it>< 0.01) and rs3804100 (adjusted OR, 0.509, 95% CI 0.342 - 0.759, <it>P </it>< 0.01). There was no significant association found in two TLR9 SNPs concerning the risk of HCC. The haplotype TT for TLR2 was associated significantly with the decreased risk of HCC (OR 0.524, 95% CI 0.394 - 0.697, <it>P </it>= 0.000). Inversely, the risk of HCC increased significantly in patients with the haplotype CC (OR 2.743, 95% CI 1.915 - 3.930, <it>P </it>= 0.000).</p> <p>Conclusions</p> <p>These results suggested that TLR2 rs3804099 C/T and rs3804100 C/T polymorphisms were closely associated with HCC. In addition, the haplotypes composed of these two TLR2 synonymous SNPs have stronger effects on the susceptibility of HCC.</p

    Studies on p53, BAX and Bcl-2 protein expression and microsatellite instability in stage III (UICC) colon cancer treated by adjuvant chemotherapy: major prognostic impact of proapoptotic BAX

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    We evaluated the expression patterns of proapoptotic BAX, antiapoptotic Bcl-2 and p53, the proposed upstream effector of these molecules, as potential prognostic markers in UICC stage III colon cancer by immunohistochemical staining. To identify high-frequency microsatellite instability (MSI+) individuals, we performed single-strand conformation polymorphism-based analysis for BAT26. A total of 188 patients who had received 5-fluorouracil (5-FU)-based adjuvant chemotherapy (5-FU/folinic acid or 5-FU/levamisole) were enrolled. Median follow-up was 84.5 months. We found that BAX, Bcl-2 and p53 protein expressions were high or positive in 59, 70 and 50% of 188 cases, respectively. MSI+ tumours were detected in 9% of 174 evaluable patients. BAX or Bcl-2 was correlated with a higher degree of differentiation or left-sided tumours (P=0.01 or P=0.03, respectively); MSI was correlated with right-sided tumours (P<0.0001). In contrast to p53, Bcl-2, or MSI, low BAX, advanced pN category, low grade of differentiation and treatment with 5-FU/levamisole were univariately associated with poorer disease-free survival (DFS) (P=0.0005, P=0.001, P=0.005 and P=0.01, respectively) and poorer overall survival (OS) (P=0.002, P=0.0001, P=0.003 and P=0.02, respectively). Besides pN category and treatment arm, BAX was an independent variable related to both OS and DFS (P=0.003 and P=0.001, respectively). In both univariate and multivariate analysis, the p53−/BAX high in comparison with the p53+/BAX high subset conferred a significantly improved DFS (P=0.03 and P=0.03, respectively) as well as a marginally improved OS (P=0.07 and P=0.08, respectively). BAX protein expression may be of central significance for clinical outcome to 5-FU-based adjuvant chemotherapy in stage III colon cancer, and bivariate analysis of p53/BAX possibly may provide further prognostic evidence

    Single Nucleotide Polymorphisms of Toll-Like Receptor 4 Decrease the Risk of Development of Hepatocellular Carcinoma

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    BACKGROUND: Toll-like receptor 4 (TLR4) is a key innate immunity receptor that initiates an inflammatory response. Growing evidence suggests that mutation of TLR4 gene may play a role in the development of cancers. This study aimed to investigate the temporal relationship of single nucleotide polymorphisms of TLR4 and the risk of hepatocellular carcinoma, a single center-based case-control study was conducted. METHODS: A systematic genetic analysis of sequence variants of TLR4 by evaluating ten single-nucleotide polymorphisms was performed from 216 hepatocellular carcinoma cases and 228 controls. RESULTS: Six single nucleotide polymorphisms of the TLR4 in the 5'-untranslated region and intron were associated with risk of hepatocellular carcinoma. Individuals carrying the heterozygous genotypes for the rs10759930, rs2737190, rs10116253, rs1927914, rs12377632 and rs1927911 had significantly decreased risk of hepatocellular carcinoma (adjusted odds ratio [OR], from 0.527 to 0.578, P<0.01) comparing with those carrying wild-type homozygous genotypes. In haplotype analysis, one haplotype (GCCCTTAG) of TLR4 was associated significantly with decrease of the occurrence of hepatocellular carcinoma (OR, 0.556, 95% confidence interval [CI], 0.407-0.758, P = 0.000). CONCLUSIONS: Collectively, these results suggested that the risk of hepatocellular carcinoma was associated with TLR4 sequence variation. TLR4 single nucleotide polymorphisms may play an important protective role in the development of hepatocellular carcinoma

    A Model of Oxidative Stress Management: Moderation of Carbohydrate Metabolizing Enzymes in SOD1-Null Drosophila melanogaster

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    The response to oxidative stress involves numerous genes and mutations in these genes often manifest in pleiotropic ways that presumably reflect perturbations in ROS-mediated physiology. The Drosophila melanogaster SOD1-null allele (cSODn108) is proposed to result in oxidative stress by preventing superoxide breakdown. In SOD1-null flies, oxidative stress management is thought to be reliant on the glutathione-dependent antioxidants that utilize NADPH to cycle between reduced and oxidized form. Previous studies suggest that SOD1-null Drosophila rely on lipid catabolism for energy rather than carbohydrate metabolism. We tested these connections by comparing the activity of carbohydrate metabolizing enzymes, lipid and triglyceride concentration, and steady state NADPH:NADP+ in SOD1-null and control transgenic rescue flies. We find a negative shift in the activity of carbohydrate metabolizing enzymes in SOD1-nulls and the NADP+-reducing enzymes were found to have significantly lower activity than the other enzymes assayed. Little evidence for the catabolism of lipids as preferential energy source was found, as the concentration of lipids and triglycerides were not significantly lower in SOD1-nulls compared with controls. Using a starvation assay to impact lipids and triglycerides, we found that lipids were indeed depleted in both genotypes when under starvation stress, suggesting that oxidative damage was not preventing the catabolism of lipids in SOD1-null flies. Remarkably, SOD1-nulls were also found to be relatively resistant to starvation. Age profiles of enzyme activity, triglyceride and lipid concentration indicates that the trends observed are consistent over the average lifespan of the SOD1-nulls. Based on our results, we propose a model of physiological response in which organisms under oxidative stress limit the production of ROS through the down-regulation of carbohydrate metabolism in order to moderate the products exiting the electron transport chain
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