438 research outputs found
Regulator of the mucoid phenotype A gene increases the virulent ability of extended-spectrum beta-lactamase-producing serotype non-K1/K2 Klebsiella pneumonia
BackgroundTo determine whether the presence of a capsule regulator gene [i.e., regulator of mucoid phenotype A (rmpA) gene] contributes to virulence on extended-spectrum β-lactamase-producing Klebsiella pneumoniae (ESBL-KP) with serotype non-K1/K2 strains.MethodsTwenty-eight ESBL-KP and non-ESBL-KP isolates were collected from the Tri-Service General Hospital (Taipei, Taiwan). The impact of the virulent rmpA gene in different capsular polysaccharide serotypes on ESBL-KP and non-ESBL-KP isolates was studied by a neutrophil phagocytosis reaction, a serum bactericidal assay, and an animal survival model.ResultsResistance to broad spectrum antibiotics was more prevalent in ESBL-KP strains than in non-ESBL-KP strains (p < 0.01). The ESBL-KP strains had different molecular patterns from non-ESBL-KP strains, based on pulsed-field gel electrophoresis. The frequency of serum-resistant isolates was the highest among ESBL-KP strains with rmpA (i.e., rmpA+) [71.4% (5/7)] than among of non-ESBL-KP rmpA+ strains [42.8% (6/14)], ESBL-KP strains without rmpA (rmpA−) [33.3% (7/21)], and non-ESBL-KP rmpA− strains [14.2% (2/14)]. The most significant increase in neutrophil resistance occurred in the ESBL-KP rmpA+ strains in comparison to the non-ESBL-KP rmpA+, ESBL-KP rmpA−, and non-ESBL-KP rmpA− strains (p < 0.01). The results of the animal survival model were compatible with the neutrophil phagocytosis reaction and serum bactericidal assay.ConclusionWe conclude that the pathogenic potential is greater in rmpA+ ESBL-KP strains than in rmpA– ESBL-KP and non-ESBL-KP strains
A lack of association between genetic polymorphisms in beta-defensins and susceptibility of psoriasis in Taiwanese: A case–control study
AbstractBackgroundGenetic predisposition of the inflammatory-host response may affect the development of psoriasis. Previous studies have shown that copy number variations (CNVs) of β-defensin genes (DEFB) are associated with the susceptibility of psoriasis in Caucasian populations.ObjectivesThis study aimed to assess the role of the CNVs of the DEFB4 gene and functional variants in the DEFB1 gene in Taiwanese patients with psoriasis.MethodsIn total, 196 patients with psoriasis and 196 control individuals were analyzed for the presence of the DEFB4 CNVs using the paralogue ratio test, and also for the DEFB1 polymorphisms rs11362, rs1800972, and rs1799946, using a polymerase chain reaction.ResultsNone of the polymorphisms were found to be associated with psoriasis. The distribution of DEFB4 genomic CNVs did not significantly differ between the control group and psoriasis group. The frequencies of patients who carried a greater than the median (≥ 5) number of copies did not significantly differ in patients with psoriasis and controls. The multivariate analysis similarly revealed that the DEFB4 CNVs were not associated with psoriasis (odds ratio = 1.03, 95% confidence interval = 0.89–1.19, p = 0.720). No significant difference was detected in the genotype and allele distribution for any of the individual DEFB1 polymorphisms between the cases and the controls. Finally, the overall haplotype frequency profiles derived from the three polymorphisms did not significantly differ between the cases and the controls.ConclusionOur results do not suggest that these genetic variants of the β-defensin genes contribute to the genetic background of psoriasis in Taiwanese patients
The microtubule-associated protein, EB1, links AIM2 inflammasomes with autophagy-dependent secretion
Inflammasomes are multi-protein complexes that regulate chronic inflammation-associated diseases by inducing interleukin-1 β (IL-1β) secretion. Numerous components involved in inflammasome activation have been identified, but the mechanisms of inflammasome-mediated IL-1β secretion have not yet been fully explored. Here, we demonstrate that end-binding protein 1 (EB1), which is required for activation of AIM2 inflammasome complex, links the AIM2 inflammasome to autophagy-dependent secretion. Imaging studies revealed that AIM2 inflammasomes colocalize with microtubule organizing centers and autophagosomes. Biochemical analyses showed that poly(dA-dT)-activated AIM2 inflammasomes induce autophagy and IL-1β secretion in an LC3-dependent fashion. Furthermore, depletion of EB1 decreases autophagic shedding and intracellular trafficking. Finally, we found that the 5′-AMP activated protein kinase may regulate this EB1-mediated autophagy-based inflammasome-induced secretion of IL-1β. These findings reveal a novel EB1-mediated pathway for the secretion of IL-1β
Phyllanthus urinaria Induces Apoptosis in Human Osteosarcoma 143B Cells via Activation of Fas/FasL- and Mitochondria-Mediated Pathways
Phyllanthus urinaria (P. urinaria), in this study, was used for the treatment of human osteosarcoma cells, which is one of the tough malignancies with few therapeutic modalities. Herein, we demonstrated that P. urinaria inhibited human osteosarcoma 143B cells growth through an apoptotic extrinsic pathway to activate Fas receptor/ligand expression. Both intracellular and mitochondrial reactive oxygen species were increased to lead to alterations of mitochondrial membrane permeability and Bcl-2 family including upregulation of Bid, tBid, and Bax and downregulation of Bcl-2. P. urinaria triggered an intrinsic pathway and amplified the caspase cascade to induce apoptosis of 143B cells. However, upregulation of both intracellular and mitochondrial reactive oxygen species and the sequential membrane potential change were less pronounced in the mitochondrial respiratory-defective 143Bρ0 cells compared with the 143B cells. This study offers the evidence that mitochondria are essential for the anticancer mechanism induced by P. urinaria through both extrinsic and intrinsic pathways
Non-invasive and transdermal measurement of blood uric acid level in human by electroporation and reverse iontophoresis
The aim of this study was to find out the optimum combination of electroporation (EP) and reverse iontophoresis (RI) on noninvasive and transdermal determination of blood uric acid level in humans. EP is the use of high-voltage electric pulse to create nano-channels on the stratum corneum, temporarily and reversibly. RI is the use of small current to facilitate both charged and uncharged molecule transportation across the skin. It is believed that the combination of these two techniques has additional benefits on the molecules’ extraction across the human skin. In vitro studies using porcine skin and diffusion cell have indicated that the optimum mode for transdermal uric acid extraction is the combination of RI with symmetrical biphasic direct current (current density = 0.3 mA/cm2; phase duration = 180 s) and EP with 10 pulses per second (voltage = 100 V/cm2; pulse width = 1 ms). This optimum mode was applied to six human subjects. Uric acid was successfully extracted through the subjects’ skin into the collection solution. A good correlation (r2 = 0.88) between the subject’s blood uric acid level and uric acid concentrations in collection solutions was observed. The results suggest that it may be possible to noninvasively and transdermally determine blood uric acid levels
Distinct Tumor Microenvironment at Tumor Edge as a Result of Astrocyte Activation Is Associated With Therapeutic Resistance for Brain Tumor
Tumor vasculatures and hypoxia are critical tumor micro-environmental factors associated with tumor response to the therapy and heterogeneous in both time- and location-dependent manner. Using a murine orthotopic anaplastic astrocytoma model, ALTS1C1, this study showed that brain tumor edge had a very unique microenvironment, having higher microvascular density (MVD) and better vessel function than the tumor core, but on the other hand was also positive for hypoxia markers, such as pimonidazole (PIMO), hypoxia inducible factor-1α (HIF-1α), and carbonic anhydrase IV (CAIX). The hypoxia at tumor edge was transient, named as peripheral hypoxia, and caused by different mechanisms from the chronic hypoxia in tumor core. The correlation of CAIX staining with astrocyte activation marker, glial fibrillary acid protein (GFAP), at the tumor edge indicated the involvement of astrocyte activation on the development of peripheral hypoxia. Peripheral hypoxia was a specific trait of orthotopic brain tumors at tumor edge, regardless of tumor origin. The hypoxic cells were resistant to the therapy, regardless of their location. Surviving cells, particularly those at the hypoxic region of tumor edge, are likely the cause of tumor recurrence after the therapy. New therapeutic platform that targets cells in tumor edge is likely to achieve better treatment outcomes
Identification of Postoperative Prognostic MicroRNA Predictors in Hepatocellular Carcinoma
Comparison of microRNA (miRNA) expression profiles in the noncancerous liver tissues adjacent to hepatocelluar carcinomas (HCCs) was a strategy to identify postoperative prognostic predictors in this study. Expression profiles of 270 miRNAs were determined in the paraneoplastic liver tissues of 12 HCC patients with known postoperative prognosis. A panel of candidate miRNA predictors was identified. The prognostic predictive value of these candidate miRNAs was then verified in 216 postoperative HCC patients. Univariate analysis identified 8 and 3 miRNA predictors for recurrence-free (RFS) and overall (OS) survivals, respectively. Multivariate analysis revealed high expression levels of miR-155 (HR, 2.002 [1.324–3.027]; P = .001), miR-15a (HR, 0.478 [0.248–0.920]; P = .027), miR-432 (HR, 1.816 [1.203–2.740]; P = .015), miR-486-3p (HR, 0.543 [0.330–0.893]; P = .016), miR-15b (HR, 1.074 [1.002–1.152]; P = .043) and miR-30b (HR, 1.102 [1.025–1.185]; P = .009) were significantly associated with RFS. When clinicopathological predictors were included, multivariate analysis revealed that tumor number and miR-432, miR-486-3p, and miR-30b expression levels remained significant as independent predictors for RFS. Additionally, expression knockdown of miR-155 in J7 and Mahlavu hepatoma cells resulted in decreased cell growth and enhanced cell death in xenograft tumors, suggesting an oncogenic effect of miR-155. In conclusion, significant prognostic miRNA predictors were identified through examination of miRNA expression levels in paraneoplastic liver tissues. Functional analysis of a miRNA predictor, miR-155, suggested that the prognostic miRNA predictors identified under this strategy could serve as potential molecular targets for anticancer therapy
- …