551 resultados para Induced Current
Resumo:
Asthma is a chronic inflammatory airways disease in which respiratory viral infections frequently trigger exacerbations. Current treatment of asthma with combinations of inhaled corticosteroids and long acting beta2 agonists improves asthma control and reduces exacerbations but what impact this might have on innate anti-viral immunity is unclear. We investigated the in vitro effects of asthma drugs on innate anti-viral immunity. Peripheral blood mononuclear cells (PBMC) from healthy and asthmatic donors were cultured for 24 hours with the Toll-like receptor 7 agonist, imiquimod, or rhinovirus 16 (RV16) in the presence of budesonide and/or formoterol. Production of proinflammatory cytokines and expression of anti-viral intracellular signalling molecules were measured by ELISA and RT-PCR respectively. In PBMC from healthy donors, budesonide alone inhibited IP-10 and IL-6 production induced by imiquimod in a concentration-dependent manner and the degree of inhibition was amplified when budesonide and formoterol were used in combination. Formoterol alone had little effect on these parameters, except at high concentrations (10−6 M) when IL-6 production increased. In RV16 stimulated PBMC, the combination of budesonide and formoterol inhibited IFNα and IP-10 production in asthmatic as well as healthy donors. Combination of budesonide and formoterol also inhibited RV16-stimulated expression of the type I IFN induced genes myxovirus protein A and 2′, 5′ oligoadenylate synthetise. Notably, RV16 stimulated lower levels of type Myxovirus A and oligoadenylate synthase in PBMC of asthmatics than control donors. These in vitro studies demonstrate that combinations of drugs commonly used in asthma therapy inhibit both early pro-inflammatory cytokines and key aspects of the type I IFN pathway. These findings suggest that budesonide and formoterol curtail excessive inflammation induced by rhinovirus infections in patients with asthma, but whether this inhibits viral clearance in vivo remains to be determined.
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Asthma prevalence in children has remained relatively constant in many Western countries, but hospital admissions for younger age groups have increased over time.1 Although the role of outdoor aeroallergens as triggers for asthma exacerbations requiring hospitalization in children and adolescents is complex, there is evidence that increasing concentrations of grass pollen are associated with an increased risk of asthma exacerbations in children.2 Human rhinovirus (HRV) infections are implicated in most of the serious asthma exacerbations in school-age children.3 In previous research, HRV infections and aeroallergen exposure have usually been studied independently. To our knowledge, only 1 study has examined interactions between these 2 factors,4 but lack of power prevented any meaningful interpretation...
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Human papilloma virus (HPV) infection is a major risk factor for a distinct subset of head and neck squamous cell carcinoma (HNSCC). The current review summarizes the epidemiology of HNSCC and the disease burden, the infectious cycle of HPV, the roles of viral oncoproteins, E6 and E7, and the downstream cellular events that lead to malignant transformation. Current techniques for the clinical diagnosis of HPV-associated HNSCC will also be discussed, that is, the detection of HPV DNA, RNA, and the HPV surrogate marker, p16 in tumor tissues, as well as HPV-specific antibodies in serum. Such methods do not allow for the early detection of HPV-associated HNSCC and most cases are at an advanced stage upon diagnosis. Novel noninvasive approaches using oral fluid, a clinically relevant biological fluid, allow for the detection of HPV and cellular alterations in infected cells, which may aid in the early detection and HPV-typing of HNSCC tumors. Noninvasive diagnostic methods will enable early detection and intervention, leading to a significant reduction in mortality and morbidity associated with HNSCC.
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The transition from a steady to an unsteady flow induced by an adiabatic fin on the sidewall of a differentially heated air-filled cavity is numerically investigated. Numerical simulations have been performed over the range of Rayleigh numbers from Ra = 105–109. The temporal development and spatial structures of natural convection flows in the cavity with a fin are described. It has been demonstrated that the fin may induce the transition to an unsteady flow and the critical Rayleigh number for the occurrence of the transition is between 3.72 × 106 and 3.73 × 106. Furthermore, the peak frequencies of the oscillations triggered by different mechanisms are obtained through spectral analysis. It has been found that the flow rate through the cavity with a fin is larger than that without a fin under the unsteady flow, indicating that the fin may improve the unsteady flow in the cavity.
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The issue of single-cell control has recently attracted enormous interest. However, in spite of the presently achievable intracellular-level physiological probing through bio-photonics, nano-probe-based, and some other techniques, the issue of inducing selective, single-cell-precision apoptosis, without affecting neighbouring cells remains essentially open. Here we resolve this issue and report on the effective single-cell-precision cancer cell treatment using the reactive chemistry of the localized corona-type plasma discharge around a needle-like electrode with the spot size ∼1 µm. When the electrode is positioned with the micrometer precision against a selected cell, a focused and highly-localized micro-plasma discharge induces apoptosis in the selected individual HepG2 and HeLa cancer cells only, without affecting any surrounding cells, even in small cell clusters. This is confirmed by the real-time monitoring of the morphological and structural changes at the cellular and cell nucleus levels after the plasma exposure.
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Animal and human studies have demonstrated that early pain experiences can produce alterations in the nociceptive systems later in life including increased sensitivity to mechanical, thermal, and chemical stimuli. However, less is known about the impact of neonatal immune challenge on future responses to noxious stimuli and the reactivity of neural substrates involved in analgesia. Here we demonstrate that rats exposed to Lipopolysaccharide (LPS; 0.05 mg/kg IP, Salmonella enteritidis) during postnatal day (PND) 3 and 5 displayed enhanced formalin-induced flinching but not licking following formalin injection at PND 22. This LPS-induced hyperalgesia was accompanied by distinct recruitment of supra-spinal regions involved in analgesia as indicated by significantly attenuated Fos-protein induction in the rostral dorsal periaqueductal grey (DPAG) as well as rostral and caudal axes of the ventrolateral PAG (VLPAG). Formalin injections were associated with increased Fos-protein labelling in lateral habenula (LHb) as compared to medial habenula (MHb), however the intensity of this labelling did not differ as a result of neonatal immune challenge. These data highlight the importance of neonatal immune priming in programming inflammatory pain sensitivity later in development and highlight the PAG as a possible mediator of this process
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The reliability of micro inverters is an important factor as it would be necessary to reduce cost and maintenance of the small and medium scale distributed PV power conversion systems. Electrolytic capacitors and active power decouple circuits can be avoided in micro inverters with the use of medium voltage DC-link. Such a DC-link based micro inverter is proposed with a front-end dual inductor current-fed push-pull converter. The primary side power switches of the front-end converter have reduced switching losses due to multi-resonant operation. In addition, the voltage and current stresses on the diodes of the secondary diode voltage doubler rectifier are reduced due to the presence of a series resonant circuit in the front-end converter. The operation of the proposed micro inverter is explained using an in-depth analysis of the switching characteristics of the power semiconductor devices. The theoretical analysis of the proposed micro inverter is validated using simulation result.
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Atmospheric pressure gas plasma (AGP) generates reactive oxygen species (ROS) that induce apoptosis in cultured cancer cells. The majority of cancer cells develop a ROS-scavenging anti-oxidant system regulated by Nrf2, which confers resistance to ROS-mediated cancer cell death. Generation of ROS is involved in the AGP-induced cancer cell death of several colorectal cancer cells (Caco2, HCT116 and SW480) by activation of ASK1-mediated apoptosis signaling pathway without affecting control cells (human colonic sub-epithelial myofibroblasts; CO18, human fetal lung fibroblast; MRC5 and fetal human colon; FHC). However, the identity of an oxidase participating in AGP-induced cancer cell death is unknown. Here, we report that AGP up-regulates the expression of Nox2 (NADPH oxidase) to produce ROS. RNA interference designed to target Nox2 effectively inhibits the AGP-induced ROS production and cancer cell death. In some cases both colorectal cancer HT29 and control cells showed resistance to AGP treatment. Compared to AGP-sensitive Caco2 cells, HT29 cells show a higher basal level of the anti-oxidant system transcriptional regulator Nrf2 and its target protein sulfiredoxin (Srx) which are involved in cellular redox homeostasis. Silencing of both Nrf2 and Srx sensitized HT29 cells, leads to ROS overproduction and decreased cell viability. This indicates that in HT29 cells, Nrf2/Srx axis is a protective factor against AGP-induced oxidative stress. The inhibition of Nrf2/Srx signaling should be considered as a central target in drug-resistant colorectal cancer treatments.
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Background Matrix metalloproteinase-2 (MMP-2) is an endopeptidase that facilitates extracellular matrix remodeling and molecular regulation, and is implicated in tumor metastasis. Type I collagen (Col I) regulates the activation of MMP-2 through both transcriptional and post-transcriptional means; however gaps remain in our understanding of the involvement of collagen-binding ?1 integrins in collagen-stimulated MMP-2 activation. Methods Three ?1 integrin siRNAs were used to elucidate the involvement of ?1 integrins in the Col I-induced MMP-2 activation mechanism. ?1 integrin knockdown was analyzed by quantitative RT-PCR, Western Blot and FACS analysis. Adhesion assay and collagen gel contraction were used to test the biological effects of ?1 integrin abrogation. MMP-2 activation levels were monitored by gelatin zymography. Results All three ?1 integrin siRNAs were efficient at ?1 integrin knockdown and FACS analysis revealed commensurate reductions of integrins ?2 and ?3, which are heterodimeric partners of ?1, but not ?V, which is not. All three ?1 integrin siRNAs inhibited adhesion and collagen gel contraction, however only the siRNA showing the greatest magnitude of ?1 knockdown inhibited Col I-induced MMP-2 activation and reduced the accompanying upregulation of MT1-MMP, suggesting a dose response threshold effect. Re-transfection with codon-swapped ?1 integrin overcame the reduction in MMP-2 activation induced by Col-1, confirming the ?1 integrin target specificity. MMP-2 activation induced by TPA or Concanavalin A (Con A) was not inhibited by ?1 integrin siRNA knockdown. Conclusion Together, the data reveals that strong abrogation of ?1 integrin is required to block MMP-2 activation induced by Col I, which may have implications for the therapeutic targeting of ?1 integrin.
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The current research began from the starting point that what we are grappling with when we are dealing with violent extremists by and large is essentially ‘normal people’. What follows in this third major section of this research paper is the theoretical and conceptual search for making researchable the following question: ‘How do you assess someone who is normal?’
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A recent hydrodynamic theory of liquid slippage on a solid substrate (Kirkinis & Davis, Phys. Rev. Lett., vol. 110, 2013, 234503) gives rise to a sequence of eddies (Moffatt vortices) that co-move with a moving contact line (CL) in a liquid wedge. The presence of these vortices is established through secular equations that depend on the dynamic contact angle α and capillary number Ca. The limiting case α→O is associated with the appearance of such vortices in a channel. The vortices are generated by the relative motion of the interfaces, which in turn is due to the motion of the CL. This effect has yet to be observed in experiment.
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Background Individuals with limb amputation fitted with conventional socket-suspended prostheses often experience socket related discomfort leading to a significant decrease in quality of life. Most of these concerns can be overcome by surgical techniques enabling bone-anchored prostheses. In this case, the prosthesis is attached directly to the residual skeleton through a percutaneous implant (e.g., screw type fixation, press-fit implant).[46, 48, 51, 52, 77, 78] The aim of this study is to present the current advances in these surgical techniques worldwide with a strong focus on the current challenges. Methods The current advances will be extracted from a systematic literature review including approximately 40 articles. The outcomes measured will include the estimation of the population worldwide as well as the complications (e.g., infection, loosening, fractures, and breakage) and the benefits (e.g., functional outcomes, health-related quality of life).[5-19, 51-53, 55, 57, 58, 62, 73, 79] Results The population of individuals fitted with a bone-anchored prosthesis is approximately 550 worldwide. Publications focusing on infection are sparse. However, the rate of superficial infection is estimated at 20%. Deep infection occurs rarely. Loosening and peri-prosthetic fractures are fairly uncommon. Breakage of implant parts occurs regularly mainly due to fall. All studies reported a significant improvement in functional level and overall quality of life. Conclusions Several commercial implants are in developments in Europe and US. The number of procedures is consistently growing worldwide. This technique might be primary way to fit a prosthesis to young and active amputees by 2025.
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Cushing's syndrome, which is characterized by excessive circulating glucocorticoid concentrations, maybe due to ACTH-dependent or -independent causes that include anterior pituitary and adrenal cortical tumors, respectively. ACTH secretion is stimulated by CRH, and we report a mouse model for Cushing's syndrome due to an N-ethyl-N-nitrosourea (ENU) induced Crh mutation at -120 bp of the promoter region, which significantly increased luciferase reporter activity and was thus a gain-of-function mutation. Crh -120/+ mice, when compared with wild-type littermates, had obesity, muscle wasting, thin skin, hair loss, and elevated plasma and urinary concentrations of corticosterone. In addition, Crh-120/+ mice had hyperglycemia, hyperfructosaminemia, hyperinsulinemia, hypercholesterolemia, hypertriglyceridemia, and hyperleptinemia but normal adiponectin. Crh -120/+ mice also had low bone mineral density, hypercalcemia, hypercalciuria, and decreased concentrations of plasma PTH and osteocalcin. Bone histomorphometry revealed Crh-120/+ mice to have significant reductions in mineralizing surface area, mineral apposition, bone formation rates, osteoblast number, and the percentage of corticoendosteal bone covered by osteoblasts, which was accompanied by an increase in adipocytes in the bone marrow. Thus, a mouse model for Cushing's syndrome has been established, and this will help in further elucidating the pathophysiological effects of glucocorticoid excess and in evaluating treatments for corticosteroid-induced osteoporosis.
Resumo:
Background Individuals with limb amputation fitted with conventional socket-suspended prostheses often experience socket related discomfort leading to a significant decrease in quality of life. Most of these concerns can be overcome by surgical techniques enabling bone-anchored prostheses. In this case, the prosthesis is attached directly to the residual skeleton through a percutaneous implant (e.g., screw type fixation, press-fit implant).[46, 48, 51, 52, 77, 78] The aim of this study is to present the current advances in these surgical techniques worldwide with a strong focus on the current challenges. Methods The current advances will be extracted from a systematic literature review including approximately 40 articles. The outcomes measured will include the estimation of the population worldwide as well as the complications (e.g., infection, loosening, fractures, and breakage) and the benefits (e.g., functional outcomes, health-related quality of life).[5-19, 51-53, 55, 57, 58, 62, 73, 79] Results The population of individuals fitted with a bone-anchored prosthesis is approximately 550 worldwide. Publications focusing on infection are sparse. However, the rate of superficial infection is estimated at 20%. Deep infection occurs rarely. Loosening and peri-prosthetic fractures are fairly uncommon. Breakage of implant parts occurs regularly mainly due to fall. All studies reported a significant improvement in functional level and overall quality of life. Conclusions Several commercial implants are in developments in Europe and US. The number of procedures is consistently growing worldwide. This technique might be primary way to fit a prosthesis to young and active amputees by 2025.
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Background: Many preterm neonates display difficulty establishing suck-feeding competence in the weeks following birth. Ineffective management of transitional feeding issues may cause patient complications, and can contribute to increased length of stay. Aims: Given that many neonatal nurseries appear to vary in their neonatal feeding management practices, the aim of this study was to investigate and document the routine level of support and intervention currently provided for preterm neonates with transitional feeding issues across the various level II (special care) nurseries (SCNs) in Queensland, Australia. Methods: A questionnaire was mailed to all Queensland SCNs in 2005 (n = 36). The questionnaire contained a series of closed-choice and short-answer questions designed to obtain information from each SCN regarding their current practices for managing transitional feeding issues in preterm neonates. Results were confirmed during a follow-up phone call. Results: Responses were obtained from 29 SCNs (80.6%). None of these nurseries reported having any formal, written policies regarding the management of transitional feeding issues in preterm neonates. Wide variations were reported in relation to the suck-feeding assessments and interventions used by staff within the various SCNs. Of the 29 nurseries, 4 (13.8%) reported using checklists or assessments to judge readiness for suck-feeds, and 5 (17.2%) reported using pulse oximetry to judge tolerance of suck-feeding attempts. Eighteen SCNs (62.1%) reported offering some form of active intervention to assist neonates with transitional feeding issues, with the most common intervention techniques reported being non-nutritive sucking during tube feeds, pre-feeding oral stimulation, and actively pacing suck-feeds. Twenty-two SCNs (75.4%) reported having access to a lactation consultant to assist mothers with breastfeeding issues. Conclusions: Differences were reported in the routine management of transitional feeding issues in preterm neonates across the various SCNs in Queensland. It is suggested that evidence based guidelines need to be developed, and that, in order to do this, further research studies are required to determine current best practice, as well as to answer remaining questions. © 2008 Elsevier Ireland Ltd. All rights reserved.