939 resultados para Active and reactive power controls


Relevância:

100.00% 100.00%

Publicador:

Resumo:

Objective: The identification of regulatory T cells (Treg cells) as CD4(+)CD25(high) cells may be upset by the increased frequency of activated effector T cells (Teff cells) in inflammatory diseases such as systemic lupus erythematosus (SLE). This study aimed to evaluate the frequency of T-cell subsets according to the expression of CD25 and CD127 in active (A-SLE) and inactive SLE (I-SLE). Methods: Peripheral blood mononuclear cells (PBMCs) from 26 A-SLE patients (SLE Disease Activity Index (SLEDAI) = 10.17 +/- 3.7), 31 I-SLE patients (SLEDAI = 0), and 26 healthy controls (HC) were analysed by multicolour flow. cytometry. Results: CD25(high) cell frequency was increased in A-SLE (5.2 +/- 5.7%) compared to I-SLE (3.4 +/- 3.4%) and HC (1.73 +/- 0.8%) (p < 0.01). However, the percentage of FoxP3(+) cells in the CD25(high) subset was decreased in A-SLE (24.6 +/- 16.4%) compared to I-SLE (33.7 +/- 16) and HC (45 +/- 25.1%) (p < 0.01). This was partly due to the increased frequency of Teff cells (CD25(high)CD127(+)FoxP3(empty set)) in A-SLE (10.7 +/- 7.3%) compared to I-SLE (8.5 +/- 6.5) and HC (6.1 +/- 1.8%) (p = 0.02). Hence the frequency of Treg cells (CD25(+/high)CD127(low/empty set)FoxP3(+)) was equivalent in A-SLE (1.4 +/- 0.8%), I-SLE (1.37 +/- 1.0%), and HC (1.13 +/- 0.59%) (p = 0.42). A-SLE presented an increased frequency of CD25(+)CD127(+)FoxP3(+) and CD25(empty set)FoxP3(+)CD127(low/empty set) T cells, which may represent intermediate phenotypes between Treg and Teff cells. Conclusions: The present study has provided data supporting normal Treg cell frequency in A-SLE and I-SLE as well as increased frequency of Teff cells in A-SLE. This scenario reflects a Treg/Teff ratio imbalance that may favour the inflammatory phenotype of the disease. In addition, the increased frequency of T cells with putative intermediate phenotypes may be compatible with a highly dynamic immune system in SLE.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Intrapleural instillation of talc has been used in the treatment of recurrent pleural effusions but can, in rare instances, result in respiratory failure. Side-effects seem to be related to composition, size and inflammatory power of talc particles. The aim of this study was to evaluate the inflammatory response to intrapleural injection of talc containing small particles (ST) or talc containing particles of mixed size (MT). 100 rabbits received intrapleural talc, 50 with ST (median 6.41 mu m) and 50 with MT median 21.15 mu m); the control group was composed of 35 rabbits. Cells, lactate dehydrogenase, C-reactive protein (CRIP), interleukin (IL)-8 and vascular endothelial growth factor were evaluated in serum and bronchoalveolar lavage at 6, 24, 48, 72 and 96 h. Lung histology and the presence of talc were also analysed. Statistics were performed using ANOVA and an unpaired t-test. Most of the parameters showed greater levels in the animals injected with talc than in the controls, suggesting a systemic and pulmonary response. Higher serum levels of CRP and IL-8 were observed in the animals injected with ST. Talc particles were observed in both lungs with no differences between groups. Lung cell infiltrate was more evident in the ST group. In conclusion, talc with larger particles should be the preferred choice in clinical practice in order to induce safer pleurodesis.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

The objective of this study is to investigate the presence of anti-nucleosome (anti-NCS) and anti-chromatin (anti-CRT) antibodies in patients with cutaneous lupus erythematosus (CLE) compared with active and inactive systemic lupus erythematosus (SLE). A total of 154 subjects were evaluated: 54 patients presenting CLE, 66 patients with active SLE and 34 with inactive SLE. Lupus activity was assessed using the disease activity index (SLEDAI). Anti-NCS and anti-CRT antibodies were detected by enzyme-linked immunosorbent assay ( ELISA). Only one of 54 patients with CLE tested positive for both anti-NCS and anti-CRT antibodies. The prevalence of anti-CRT antibodies was significantly higher in active SLE (84.8%) when compared with inactive SLE (26.4%) and CLE (1.8%) ( P < 0.001). Anti-NCS antibodies were also more prevalent in active SLE patients (74.2%) than inactive SLE (11.7%) and CLE patients ( 1.8%) ( P < 0.001). The presence of anti-CRT and anti-NCS antibodies was correlated to disease activity in patients with SLE (r = 0.4937, r = 0.5621, respectively). Furthermore, the detection of both antibodies was correlated with disease activity in patients with SLE who tested negative for anti-dsDNA antibodies ( r = 0.4754 for anti-NCS and r = 0.4281 for anti-CRT). The presence of these two auto-antibodies was strongly associated with renal damage in patients with SLE ( OR = 13.1, for anti-CRT antibodies and OR = 25.83, for anti-NCS antibodies). The anti-NCS and anti-CRT antibodies were not found in CLE. In patients with SLE, there is a correlation of these antibodies with disease activity and active nephritis. When compared with anti-dsDNA antibodies, anti-NCS and anti-CRT antibodies were more sensitive in detecting disease activity and kidney damage in lupus patients. Lupus (2009) 18, 223-229.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Patients presenting with active Systemic lupus erythematosus (SLE) manifestations may exhibit distinct pathogenetic features in relation to inactive SLE. Also, cDNA microarrays may potentially discriminate the gene expression profile of a disease or disease variant. Therefore, we evaluated the expression profile of 4500 genes in peripheral blood lymphocytes (PBL) of SLE patients. We studied 11 patients with SLE (seven with active SLE and four with inactive SLE) and eight healthy controls. Total RNA was isolated from PBL, reverse transcribed into cDNA, and postlabeled with Cy3 fluorochrome. These probes were then hybridized to a glass slide cDNA microarray containing 4500 human IMAGE cDNA target sequences. An equimolar amount of total RNA from human cell lines served as reference. The microarray images were quantified, normalized, and analyzed using the R environment (ANOVA, significant analysis of microarrays, and cluster-tree view algorithms). Disease activity was assessed by the SLE disease activity index. Compared to the healthy controls, 104 genes in active SLE patients (80 repressed and 24 induced) and 52 genes in nonactive SLE patients (31 induced and 21 repressed) were differentially expressed. The modulation of 12 genes, either induced or repressed, was found in both disease variants; however, each disease variant had differential expression of different genes. Taken together, these results indicate that the two lupus variants studied have common and unique differentially expressed genes. Although the biological significance of the differentially expressed genes discussed above has not been completely understood, they may serve as a platform to further explore the molecular basis of immune deregulation in SLE.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

This retrospective study analyzed the HLA-B*27 alleles in a group of 20 consecutive patients with the diagnosis of Reiter syndrome (RS) followed in a tertiary referral university hospital in Brazil, during the period 1990-2006, and compared the data with that observed in other patients with spondyloarthropathies followed at the same institution. Eight cases were associated to gastrointestinal infection, eight cases to previous urethritis, and four cases presented no established preceding infection. HLA-B*27 alleles were typed by polymerase chain reaction-amplified DNA hybridized with sequence-specific oligonucleotide probes (HLA-B*2701 to HLA-B*2721). They were compared to a group of 108 patients with ankylosing spondylitis (AS), 40 with undifferentiated spondyloarthropathy (uSpA) and 111 healthy controls. Among the 20 patients, 17 were HLA-B*27 positive (85%). Two HLA-B*27 alleles were observed: HLA-B*2705 (65%) and HLA-B*2702 (35%). In the other spondyloarthropathies, the observed alleles were HLA-B*2705 (90% in AS and 92.5% in uSpA), HLA-B*2702 (8% in AS and 5% in uSpA), HLA-B*2704 (1% in AS and 2.5% in uSpA) and HLA-B*2713 (1% in AS). Among the 111 healthy controls, 80% presented HLA-B*2705, followed by HLA-B*2702 in 10%, HLA-B*2703 in 6%, HLA-B*2707 in 3% and HLA-B*2713 in 1%. Concluding, in the HLA-B*27 positive patients with RS in this study there was predominance of HLA-B*2705 allele, in a lower frequency than that observed in patients with other spondyloarthropathies and healthy controls.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Cytokines play important roles in the pathogenesis of lipodystrophy syndrome (LS). Single nucleotide polymorphisms (SNPs) at positions -607(C/A) and -137(C/G) in the promoter region of the interleukin-18 (IL-18) gene and at position +874(T/A) of the interferon-gamma (IFN-gamma) gene are related to the expression of these cytokines. To examine whether IL-18 and IFN-gamma polymorphisms are associated with LS, these SNPs were genotyped in 88 human immunodeficiency virus (HIV)-infected patients presenting LS, 79 HIV-infected without LS, and 133 healthy controls. The -607A allele, -607AA genotype, and -137G/-607A and -137C/-607A haplotypes in the IL-18 gene were over-represented in HIV patients presenting LS. The -137G/-607C haplotype was associated with protection against LS. These results indicate that the -607(C/A) SNP is associated with LS development in HIV-infected patients.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Purpose: Eicosapentaenoic acid has been tested in bladder cancer as a synergistic cytotoxic agent in the form of meglumine-eicosapentaenoic acid, although its mechanism of action is poorly understood in this cancer. The current study analyzed the mechanisms by which eicosapentaenoic acid alters T24/83 human bladder cancer metabolism in vitro. Materials and Methods: T24/83 human bladder cancer cells were exposed to eicosapentaenoic acid for 6 to 24 hours in vitro and incorporation profiles were determined. Effects on membrane phospholipid incorporation, energy metabolism, mitochondrial activity, cell proliferation and apoptosis were analyzed Reactive oxygen species and lipid peroxide production were also determined. Results: Eicosapentaenoic acid was readily incorporated into membrane phospholipids with a considerable amount present in mitochondrial cardiolipin. Energy metabolism was significantly altered by eicosapentaenoic acid, accompanied by decreased mitochondrial membrane potential, and increased lipid peroxide and reactive oxygen species generation. Subsequently caspase-3 activation and apoptosis were detected in eicosapentaenoic acid exposed cells, leading to decreased cell numbers. Conclusions: These findings confirm that eicosapentaenoic acid is a potent cytotoxic agent in bladder cancer cells and provide important insight into the mechanisms by which eicosapentaenoic acid causes these changes. The changes in membrane composition that can occur with eicosapentaenoic acid likely contribute to the enhanced drug cytotoxicity reported previously in meglumine-eicosapentaenoic acid/epirubicin/mitomycin studies. Dietary manipulation of the cardiolipin fatty acid composition may provide an additional method for stimulating cell death in bladder cancer. In vivo studies using intravesical and dietary manipulation of fatty acid metabolism in bladder cancer merit further attention.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Background and Objective: Oral mucositis is a dose-limiting and painful side effect of radiotherapy (RT) and/or chemotherapy in cancer patients. The purpose of the present study was to analyze the effect of different protocols of laser phototherapy (LPT) on the grade of mucositis and degree of pain in patients under RT. Patients and Methods: Thirty-nine patients were divided into three groups: G1, where the irradiations were done three times a week using low power laser; G2, where combined high and low power lasers were used three time a week; and G3, where patients received low power laser irradiation once a week. The low power LPT was done using an InGaAlP laser (660 nm/40 mW/6 J cm(-2)/0.24 J per point). In the combined protocol, the high power LPT was done using a GaAlAs laser (808 nm, 1 W/cm(2)). Oral mucositis was assessed at each LPT session in accordance to the oral-mucositis scale of the National Institute of the Cancer-Common Toxicity criteria (NIC-CTC). The patient self-assessed pain was measured by means of the visual analogue scale. Results: All protocols of LPT led to the maintenance of oral mucositis scores in the same levels until the last RT session. Moreover, LPT three times a week also maintained the pain levels. However, the patients submitted to the once a week LPT had significant pain increase; and the association of low/high LPT led to increased healing time. Conclusions: These findings are desired when dealing with oncologic patients under RT avoiding unplanned radiation treatment breaks and additional hospital costs. Lasers Surg.Med. 41:264-270,2009. (C) 2009Wiley-Liss, Inc.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Aim To evaluate the bond strength of AH Plus and Epiphany sealers to human root canal dentine irradiated with a 980 nm diode laser at different power and frequency parameters, using the push-out test. Methodology Sixty canine roots were sectioned below the cementoenamel junction to provide 4-mm-thick dentine discs that had their root canals prepared with a tapered bur and irrigated with sodium hypochlorite, ethylenediaminetetraacetic acid and distilled water. The specimens were assigned to five groups (n = 12): one control (no laser) and four experimental groups that were submitted to 980 nm diode laser irradiation at different power (1.5 and 3.0 W) and frequency (continuous wave and 100 Hz) parameters. Half of specimens in each group had their canals filled with AH Plus sealer and half with Epiphany. The push-out test was performed and data (MPa) were analysed statistically by ANOVA and Tukey`s test (P < 0.05). The specimens were split longitudinally and examined under SEM to assess the failure modes after sealer displacement. Results The specimens irradiated with the diode laser and filled with AH Plus had significantly higher bond strength values (8.69 +/- 2.44) than those irradiated and filled with Epiphany (3.28 +/- 1.58) and the nonirradiated controls (3.86 +/- 0.60). The specimens filled with Epiphany did not differ significantly to each other or to the control (1.75 +/- 0.69). There was a predominance of adhesive failures at Epiphany-dentine interface (77%) and mixed failures at AH Plus-dentine interface (67%). Conclusions The 980 nm diode laser irradiation of root canal dentine increased the bond strength of AH Plus sealer, but did not affect the adhesion of Epiphany sealer.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Evidence suggests that women who are mothers of young children have lower levels of physical activity than women of similar age who do not have children (Brown, Lee, Mishra, & Bauman, 2000). The purposes of this study were to explore the factors that constrain mothers of young children from being more physically active, and the relationship between physical activity and levels of social support available to the women. The empirical basis for this examination was provided through a study of activity levels and barriers to physical activity experienced by a sample of 543 mothers of young children from differing socioeconomic backgrounds. The data indicate that: (a) more than two-thirds of the mothers were inadequately active in their leisure time for health benefit; (b) while the vast majority of mothers expressed a desire to be more active, they were inhibited in their ability to act out their leisure preferences by a combination of structural (e.g., lack of time, money, energy) and ideological influences (e.g., sense of commitment to others); (c) access to social support (from partners, family, and friends) was seen to place some women in a better position than others to negotiate constraints that inhibit leisure participation; and (d) within groups of varying socioeconomic status (SES) there was wide variation in the amount of time spent each week in active leisure.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Abnormal patterns of trunk muscle activity could affect the biomechanics of spinal movements and result in back pain. The present study aimed to examine electromyographic (EMG) activity of abdominal and back muscles as well as triaxial torque output during isometric axial rotation at different exertion levels in back pain patients and matched controls. Twelve back pain patients and 12 matched controls performed isometric right and left axial rotation at 100%, 70%, 50%, and 30% maximum voluntary contractions in a standing position. Surface EMG activity of rectus abdominis, external oblique, internal oblique, latissimus dorsi, iliocostalis lumborum and multifidus were recorded bilaterally. The primary torque in the transverse plane and the coupling torques in sagittal and coronal planes were measured. Results showed that there was a trend (P = 0.08) of higher flexion coupling torque during left axial rotation exertion in back pain patients. Higher activity for external oblique and lower activity for multifidus was shown during left axial rotation exertion in back pain group when compared to the control group. In right axial rotation, back pain patients exhibited lesser activity of rectus abdominis at higher levels of exertion when compared with matched controls. These findings demonstrated that decreased activation of one muscle may be compensated by overactivity in other muscles. The reduced levels of activity of the multifidus muscle during axial rotation exertion in back pain patients may indicate that spinal stability could be compromised. Future studies should consider these alternations in recruitment patterns in terms of spinal stability and internal loading. The findings also indicate the importance of training for coordination besides the strengthening of trunk muscles during rehabilitation process. (C) 2002 Orthopaedic Research Society. Published by Elsevier Science Ltd. All rights reserved.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

As survival of patients with CF increases,glucose intolerance and cystic fibrosisrelated diabetes (CFRD),ar e increasingly recognised common complications. CFRD may be preceded by a pre-diabetic state. Using markers identified as being associated with CFRD may improve targeted screening. Aim: To identify features consistently predicting CFRD in paediatric patients. Patients diagnosed with CFRD between January 1997–January 2002 were compared with age and sex matched controls. Clinical,micr obiological, and hospitalisation data was collected at time of CFRD diagnosis,and at six monthly intervals for 3 yr prior to diagnosis. Eight patients with CFRD were identified,mean age 13.7 yr (S.D. 3.49) at time of diagnosis. Control patients underwent OGTT to ensure normal glucose tolerance. Patients with CFRD had a lower FEV1 up to 12 months prior to diagnosis however, this was only significant at diagnosis. There was no difference in weight and height z scores between the 2 groups; however,the decrease in weight and height z scores in the CFRD group over 3 yr prior to diagnosis was significant. Mean number of days in hospital and admissions per patient significantly increased in the CFRD group,6 months prior to diagnosis. No other significant differences were observed between the 2 groups. Conclusions: This study has shown a difference in lung function,gr owth parameters and frequency of hospital admissions between patients with CFRD and controls. These differences may be utilised as tools for targeted screening in the paediatricyadolescent population. Further larger scale studies are required to improve guidelines for targeted screening in this population.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Since the 1990s, alongside China's economic growth, the international community has fostered a general anxiety towards a "China threat." In order to relieve itself from suspicion, China adopted the dual strategies of "harmonious worldview" and "good neighbor policy." The strategies led to the use of soft power in China's foreign policy. China aimed to reduce security concerns implied by the threat theory by supporting an image that caters to international peace and development. This article seeks to explain how China achieves its interests in Southeast Asia through the use of soft power. The authors address the concepts of "harmonious worldview" and "good neighbor policy" and how the twin strategies and soft power have shaped China's foreign policy in recent years. This article aims to provide insights into China's policy options in Southeast Asia in the near future.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Sliding mode controllers for power converters usually employ hysteresis comparators to directly generate the power semiconductors switching states. This paper presents a new sliding mode modulator based on the direct implementation of the sliding mode stability condition, which for multilevel power converters shows advantages, as branch equalized switching frequencies and less distortion on the ac currents when operating near the rated converter power. The new sliding mode multilevel modulator is used to control a three-phase multilevel converter, operated as a reactive power compensator (STATCOM), implementing the stability condition in a digital signal processing system. The performance of this new sliding mode modulator is compared with a multilevel modulator based on hysteresis comparators. Simulation and experimental results are presented in order to highlight the system operation and control robustness.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

This paper presents new integrated model for variable-speed wind energy conversion systems, considering a more accurate dynamic of the wind turbine, rotor, generator, power converter and filter. Pulse width modulation by space vector modulation associated with sliding mode is used for controlling the power converters. Also, power factor control is introduced at the output of the power converters. Comprehensive performance simulation studies are carried out with matrix, two-level and multilevel power converter topologies in order to adequately assert the system performance. Conclusions are duly drawn.