Electrodeposition of polypyrrole-multiwalled carbon nanotube-glucose oxidase nanobiocomposite film for the detection of glucose

A nanobiocomposite film consisted of polypyrrole (PPy), functionalized multiwalled carbon nanotubes (cMWNTs), and glucose oxidase (GOx) were electrochemically synthesized by electrooxidation of 0.1M pyrrole in aqueous solution containing appropriate amounts of cMWNTs and GOx. Potentiostatic growth profiles indicate that the anionic cMWNTs is incorporated within the growing PPy-cMWNTs nanocomposite for maintaining its electrical neutrality. The morphology of the PPy-cMWNTs nanocomposite was characterized by scanning electron microscopy (SEM). The PPy-cMWNTs nanocomposite was deposited homogeneously onto glassy carbon electrode. The amperometric responses vary proportionately to the concentration of hydrogen peroxide at the PPy-cMWNTs nanocomposite modified electrode at an operating potential of 0.7V versus Ag/AgCl (3M). The results indicate that the electroanalytical PPy-cMWNTs-GOx nanobiocomposite film was highly sensitive and suitable for glucose biosensor based on GOx function. The GOx concentration within the PPy-cMWNTs-GOx nanobiocomposite and the film thickness are crucial for the performance of the glucose biosensor. The amperometric responses of the optimized PPy-cMWNTs-GOx glucose biosensor (1.5 mgmL(-1) GOx, 141 mCcm(-2) total charge) displayed a sensitivity of 95 nAmM(-1), a linear range up to 4mM, and a response time of about 8s.     

CXC chemokine receptor-2 ligands are necessary components of neutrophil-mediated host defense in invasive pulmonary aspergillosis

Invasive pulmonary aspergillosis is a devastating complication of immunosuppression, which occurs in association with neutrophil dysfunction or deficiency. ELR+ CXC chemokines are a subfamily of chemokines that play a critical role in neutrophil chemotaxis and activation both in vitro and in vivo. We hypothesized that interaction of these ligands with CXC chemokine receptor-2 (CXCR2), their sole murine receptor, is a major component of neutrophil-dependent pulmonary host defense against Aspergillus fumigatus. In immunocompetent animals, neutrophils were recruited to the lung in response to intratracheally administered A. fumigatus conidia. In a model of transient in vivo depletion of neutrophils, animals developed invasive pulmonary aspergillosis, associated with delayed influx of neutrophils into the lung. In both normal and neutrophil-depleted animals, the ELR+ CXC chemokines MIP-2 and KC were induced in response to intratracheal administration of conidia. Ab-mediated neutralization of the common ELR+ CXC chemokine receptor, CXCR2, resulted in development of invasive disease indistinguishable from the disease in neutrophil-depleted animals, while control animals were highly resistant to the development of infection. CXCR2 neutralization was associated with reduced lung neutrophil influx and resulted in a marked increase in mortality compared with controls. In contrast, animals with constitutive lung-specific transgenic expression of KC were resistant to the organism, with reduced mortality and lower lung burden of fungus. We conclude that CXCR2 ligands are essential mediators of host defense against A. fumigatus, and may be important targets in devising future therapeutic strategies in this disease.     

Association of DLA‐DQB1 alleles with exocrine pancreatic insufficiency in Pembroke Welsh Corgis

Exocrine pancreatic insufficiency (EPI) is a digestive disorder resulting from the insufficient secretion of enzymes from the pancreas. In dogs, this condition is often attributed to pancreatic acinar atrophy, wherein the enzyme‐producing acinar cells are believed to be destroyed through an autoimmune process. Although EPI affects many diverse breeds, to date, molecular studies have been limited to the German Shepherd dog. A recent study of major histocompatibility genes in diseased and healthy German Shepherd dogs identified both risk and protective haplotypes. Herein, we genotyped DLA‐DQB1 in Pembroke Welsh Corgis to determine whether dog leukocyte antigen alleles contribute to the pathogenesis of EPI across dog breeds. We evaluated 14 affected and 43 control Pembroke Welsh Corgis, which were selected based on an age of onset similar to German Shepherd dogs. We identified one protective allele (odds ratio = 0.13, P‐value = 0.044) and one risk allele (odds ratio = 3.8, P‐value = 0.047). As in German Shepherd dogs, the risk allele is a duplication of DLA‐DQB1 (alleles DQB1*013:03 and 017:01); however, Pembroke Welsh Corgis have acquired a single polymorphism on DQB1*017:01. Thus, the DLA‐DQB1 duplication is a risk allele for EPI in at least two breeds.     

Baicalein induces proliferation inhibition in B16F10 melanoma cells by generating reactive oxygen species via 12-lipoxygenase

In a previous study, we demonstrated that baicalein induces hydroxyl radical formation in human platelets but the mechanisms are unclear. Herein, we show, using an electron spin resonance technique, that baicalein also induces hydroxyl radical formation in B16F10 melanoma cells in a dose-dependent manner. Baicalein produced superoxide anions in the presence of an iron chelator and superoxide dismutase (SOD) inhibitor. We suggest that superoxide anions produced by baicalein were promptly converted to hydroxyl radicals through SOD and the Fenton reaction in B16F10 melanoma cells. According to Western blotting results, the 12-LOX protein was expressed in B16F10 melanoma cells, but baicalein had no effect on 12-LOX expression. Decreases in 12-LOX protein expression and hydroxyl radical signals occurred in a 12-LOX small interfering RNA knockdown protein group compared with the baicalein control. In the MTT assay, we also found that baicalein caused a reduction in cellular viability, which was reversed by the addition of ROS scavengers. On the basis of these data, we conclude that ROS formation catalyzed by 12-LOX is one possible mechanism of growth inhibition by baicalein in B16F10 melanoma cells.     

Mite allergen Der-p2 triggers human B lymphocyte activation and Toll-like receptor-4 induction

Background

Allergic disease can be characterized as manifestations of an exaggerated inflammatory response to environmental allergens triggers. Mite allergen Der-p2 is one of the major allergens of the house dust mite, which contributes to TLR4 expression and function in B cells in allergic patients. However, the precise mechanisms of Der-p2 on B cells remain obscure.

Methodology/Principal Findings

We investigated the effects of Der-p2 on proinflammatory cytokines responses and Toll-like receptor-4 (TLR4)-related signaling in human B cells activation. We demonstrated that Der-p2 activates pro-inflammatory cytokines, TLR4 and its co-receptor MD2. ERK inhibitor PD98059 significantly enhanced TLR4/MD2 expression in Der-p2-treated B cells. Der-p2 markedly activated mitogen-activated protein kinase (MAPK) phosphatase-1 (MKP-1) and decreased p38 phosphorylation in B cells. MKP-1-siRNA downregulated TLR4/MD2 expression in Der-p2-treated B cells. In addition, Der-p2 significantly up-regulated expression of co-stimulatory molecules and increased B cell proliferation. Neutralizing Der-p2 antibody could effectively abrogate the Der-p2-induced B cell proliferation. Der-p2 could also markedly induce NF-κB activation in B cells, which could be counteracted by dexamethasone.

Conclusions/Significance

These results strongly suggest that Der-p2 is capable of triggering B cell activation and MKP-1-activated p38/MAPK dephosphorylation-regulated TLR4 induction, which subsequently enhances host immune, defense responses and development of effective allergic disease therapeutics in B cells.     

Autosomal dominant avascular necrosis of femoral head in two Taiwanese pedigrees and linkage to chromosome 12q13

Avascular necrosis of the femoral head (ANFH) is a debilitating disease that commonly leads to destruction of the hip joint in adults. The etiology of ANFH is unknown, but previous studies have indicated that heritable thrombophilia (increased tendency to form thrombi) and hypofibrinolysis (reduced ability to lyse thrombi), alcohol intake, and steroid use are risk factors for ANFH. We recently identified two families with ANFH showing autosomal dominant inheritance. By applying linkage analysis to a four-generation pedigree, we excluded linkage between the family and three genes related to thrombophilia and hypofibrinolysis: protein C, protein S, and plasminogen activator inhibitor. Furthermore, by a genomewide scan, a significant two-point LOD score of 3.45 (recombination fraction [theta] = 0) was obtained between the family with ANFH and marker D12S85 on chromosome 12. High-resolution mapping was conducted in a second family with ANFH and replicated the linkage to D12S368 (pedigree I: LOD score 2.47, theta = 0.05; pedigree II: LOD score 2.81, theta = 0.10). When an age-dependent-penetrance model was applied, the combined multipoint LOD score was 6.43 between D12S1663 and D12S85. Thus, we mapped the candidate gene for autosomal dominant ANFH to a 15-cM region between D12S1663 and D12S1632 on chromosome 12q13.     

Betel Nut Chewing Is Strongly Associated With General and Central Obesity in Chinese Male Middle‐aged Adults

Betel nut chewing has been reported to increase the risk of cardiovascular disease and all‐cause mortality. The reason is unclear. In this study, we investigated the association between betel nut chewing and general obesity (BMI ≥25 kg/m²) and central obesity (waist circumference (WC) ≥90 cm). A total of 1,049 male subjects, aged ≥40 years, were recruited from Taichung city in Taiwan in 2004. The relationships between betel nut chewing and general and central obesity were studied by multiple linear and logistic regression analyses. The prevalence of current and former betel nut chewing was 7.0 and 10.5% in our male Taiwanese cohort. Current/former betel nut chewers had a higher prevalence of general and central obesity when compared with individuals who had never chewed betel nut. Adjusted for age, diabetes, hypertension, lipids, smoking, alcohol drinking, physical activity, income, and education level, the odds ratios (ORs; 95% confidence intervals) of general and central obesity among the lower consumption of betel nut chewers were 1.78 (1.07, 2.96) and 1.19 (0.70, 2.02), respectively, compared to 2.01 (1.18, 3.41) and 1.89 (1.10, 3.23), respectively, among higher consumption chewers compared to individuals who had never chewed betel nut. The increasing ORs of general and central obesity with higher betel nut consumption revealed dose–response effects. Using multiple linear regression analyses, after adjusting for potential confounders, betel nut consumption was statistically significantly associated with BMI and WC. In conclusion, betel nut chewing was independently associated with general and central obesity in Taiwanese men. Dose–response effects of the association between betel nut consumption and general obesity as well as central obesity were found.