117 resultados para Frequency response model
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Mice expressing human cholesteryl ester transfer protein (huCETP) are more resistant to Escherichia coli bacterial wall LIPS because death rates 5 days after intraperitoneal inoculation of LIPS were higher in wild-type than in huCETP(+/-) mice, whereas all huCETP(+/+) mice remained alive. After LIPS inoculation, plasma concentrations of TNF-alpha and IL-6 increased less in huCETP(+/+) than in wild-type mice. LPS in vitro elicited lower TNF-alpha production by CETP expressing than by wild-type macrophages. In addition, TNF-alpha production by RAW 264.7 murine macrophages increased on incubation with LPS but decreased in a dose-dependent manner when human CETP was added to the medium. Human CETP in vitro enhanced the LIPS binding to plasma high-density lipoprotein/low-density lipoprotein. The liver uptake of intravenous infused C-14-LPS from Salmonella typhimurium was greater in huCETP(+/+) than in wild-type mice. Present data indicate for the first time that CETP is an endogenous component involved in the first line of defense against an exacerbated production of proinflammatory mediators.
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Background: Studies have investigated the influence of neuromuscular electrostimulation on the exercise/muscle capacity of patients with heart failure (HF), but the hemodynamic overload has never been investigated. The aim of our study was to evaluate the heart rate (HR), systolic and diastolic blood pressures in one session of strength exercises with and without neuromuscular electrostimulation (quadriceps) in HF patients and in healthy subjects. Methods: Ten (50% male) HF patients and healthy subjects performed three sets of eight repetitions with and without neuromuscular electrostimulation randomly, with one week between sessions. Throughout, electromyography was performed to guarantee the electrostimulation was effective. The hemodynamic variables were measured at rest, again immediately after the end of each set of exercises, and during the recovery period. Results: Systolic and diastolic blood pressures did not change during each set of exercises among either the HF patients or the controls. Without electrostimulation: among the controls, the HR corresponding to the first (85 +/- 13 bpm, p = 0.002), second (84 +/- 10 bpm, p < 0.001), third (89 +/- 17, p < 0.001) sets and recuperation (83 +/- 16 bpm, p = 0.012) were different compared to the resting HR (77 bpm). Moreover, the recuperation was different to the third set (0.018). Among HF patients, the HR corresponding to the first (84 +/- 9 bpm, p = 0.041) and third (84 +/- 10 bpm, p = 0.036) sets were different compared to the resting HR (80 +/- 7 bpm), but this increase of 4 bpm is clinically irrelevant to HF. With electrostimulation: among the controls, the HR corresponding to the third set (84 +/- 9 bpm) was different compared to the resting HR (80 +/- 7 bmp, p = 0.016). Among HF patients, there were no statistical differences between the sets. The procedure was well tolerated and no subjects reported muscle pain after 24 hours. Conclusions: One session of strength exercises with and without neuromuscular electrostimulation does not promote a hemodynamic overload in HF patients. (Cardiol J 2011; 18,1: 39-46)
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BACKGROUND: Recently, studies have been conducted examining the efficacy of 3% hypertonic saline solution (HS) for the treatment of traumatic brain injury; however, few studies have analyzed the effects of 3% hemorrhagic shock during hemorrhagic shock. The aim of this study was to test the potential immunomodulatory benefits of 3% hemorrhagic shock resuscitation over standard fluid resuscitation. METHODS: Wistar rats were bled to a mean arterial pressure of 35 mm Hg and then randomized into 3 groups: those treated with lactated Ringer`s solution (LR; 33 mL/kg, n = 7), 3% HS (10 mL/kg, n = 7), and 7.5% HS (4 mL/kg, n = 7). Half of the extracted blood was reinfused after fluid resuscitation. Animals that did not undergo shock served as controls (n = 5). Four hours after hemorrhagic shock, blood was collected for the evaluation of tumor necrosis factor-a and interleukin-6 by enzyme immunoassay. Lung and intestinal samples were obtained for histopathologic analysis. RESULTS: Animals in the HS groups had significantly higher mean arterial pressure than those in the LR group 1 hour after treatment. Osmolarity and sodium levels were markedly elevated in the HS groups. Tumor necrosis factor-alpha and interleukin-6 levels were similar between the control and HS groups but significantly higher in the LR group (P < .05). The lung injury score was significantly higher in the LR group compared with the 7.5% HS and 3% HS groups (5.7 +/- 0.7, 2.1 +/- 0.4, and 2.7 +/- 0.5, respectively). Intestinal injury was attenuated in the 7.5% HS and 3% HS groups compared with the LR group (2.0 +/- 0.6, 2.3 +/- 0.4, and 5.9 +/- 0.6, respectively). CONCLUSIONS: A small-volume resuscitation strategy modulates the inflammatory response and decreases end-organ damage after HS. Three percent HS provides immunomodulatory and metabolic effects similar to those observed with conventional concentrations of HS. (C) 2009 Elsevier Inc. All rights reserved.
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Aerobic training (AT) decreases dyspnoea and exercise-induced bronchospasm, and improves aerobic capacity and quality of life; however, the mechanisms for such benefits remain poorly understood. The aim of the present study was to evaluate the AT effects in a chronic model of allergic lung inflammation in mice after the establishment of airway inflammation and remodelling. Mice were divided into the control group, AT group, ovalbumin (OVA) group or OVA+AT group and exposed to saline or OVA. AT was started on day 28 for 60 min five times per week for 4 weeks. Respiratory mechanics, specific immunoglobulin (Ig)E and IgG(1), collagen and elastic fibres deposition, smooth muscle thickness, epithelial mucus, and peribronchial density of eosinophils, CD3+ and CD4+, IL-4, IL-5, IL-13, interferon-gamma, IL-2, IL-1ra, IL-10, nuclear factor (NF)-kappa B and Foxp3 were evaluated. The OVA group showed an increase in IgE and IgG1, eosinophils, CD3+, CD4+, IL-4, IL-5, IL-13, NF-kappa B, collagen and elastic, mucus synthesis, smooth muscle thickness and lung tissue resistance and elastance. The OVA+AT group demonstrated an increase of IgE and IgG(1), and reduction of eosinophils, CD3+, CD4+, IL-4, IL-5, IL-13, NF-kappa B, airway remodelling, mucus synthesis, smooth muscle thickness and tissue resistance and elastance compared with the OVA roup (p < 0.05). The OVA+AT group also showed an increase in IL-10 and IL-1ra (p < 0.05), independently of Foxp3. AT reversed airway inflammation and remodelling and T-helper cell 2 response, and improved respiratory mechanics. These results seem to occur due to an increase in the expression of IL-10 and IL-1ra and a decrease of NF-kappa B.
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Matrix metalloproteinases (MMPs) are crucial to the development and maintenance of healthy tissue and are mainly involved in extracellular matrix (ECM) remodeling of skeletal muscle. This study evaluated the effects of chronic allergic airway inflammation (CAAI), induced by ovalbumin, and aerobic training in the MMPs activity in mouse diaphragm muscle. Thirty mice were divided into 6 groups: 1) control; 2) ovalbumin; 3) treadmill trained at 50% of maximum speed; 4) ovalbumin and trained at 50%; 5) trained at 75%; 6) ovalbumin and trained at 75%. CAAI did not after MMPs activities in diaphragm muscle. Nevertheless, both treadmill aerobic trainings, associated with CAAI increased the MMP-2 and -1 activities. Furthermore, MMP-9 was not detected in any group. Together, these findings suggest an ECM remodeling in diaphragm muscle of asthmatic mice submitted to physical training. This result may be useful for a better understanding of functional significance of changes in the MMPs activity in response to physical training in asthma.
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Background: Attention deficit hyperactivity disorder (ADHD) is a clinically significant disorder in adulthood, but current diagnostic criteria and instruments do not seem to adequately capture the complexity of the disorder in this developmental phase. Accordingly, there are limited data on the proportion of adults affected by the disorder, specially in developing countries. Method: We assessed a representative household sample of the Brazilian population for ADHD with the Adult ADHD Self-report Scale (ASRS) Screener, and evaluated the instrument according to the Rasch model of item response theory. Results: The sample was comprised by 3007 individuals, and the overal prevalence of positive screeners for ADHD was 5.8% [95% confidence interval (CI), 4.8-7.0]. Rasch analyses revealed the misfitt of the overall sample to expectations of the model. The evaluation of the sample stratified by age revealed that data for adolescents showed a signficant fittnes to the model expectations, while items completed by adults were not adequated. Conclusions: The lack of fitness to the model for adult respondents challenges the possibility of a linear transformation of the ordinal data into interval measures and the utilization of parametric analyses of data. This result suggests that diagnostic criteria and instruments for adult ADHD must take into account a developmental perspective. Moreover, it calls for further evaluation of currently employed research methods in light of modern theories of psychometrics. Copyright (C) 2010 John Wiley & Sons, Ltd.
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Little is known about the effect of clinical characteristics, parental psychopathology, family functioning, and environmental stressors in the response to methylphenidate in children with attention-deficit/hyperactivity disorder (ADHD) followed up in a naturalistic setting. Data from cultures outside the United States are extremely scarce. This is a longitudinal study using a nonrandom assignment, quasi-experimental design. One hundred twenty-five children with ADHD were treated with methylphenidate according to standard clinical procedures, and followed up for 6 months. The severity of ADHD symptoms was assessed by the Swanson, Nolan, and Pelham rating scale. In the final multivariate model, ADHD combined subtype (P < 0.001) and comorbidity with oppositional defiant disorder (P = 0.03) were both predictors of a worse clinical response. In addition, the levels of maternal ADHD symptoms were also associated with worse prognosis (P < 0.001). In the context of several adverse psychosocial factors assessed, only undesired pregnancy was associated with poorer response to methylphenidate in the final comprehensive-model (P = 0.02). Our study provides evidence for the involvement of clinical characteristics, maternal psychopathology, and environmental stressors in the response to methylphenidate. Clinicians may consider adjuvant strategies when negative predictors are present to increase the chances of success with methylphenidate treatment.
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The impact of genetic factors on asthma is well recognized but poorly understood. We tested the hypothesis that different mouse strains present different lung tissue strip mechanics in a model of chronic allergic asthma and that these mechanical differences may be potentially related to changes of extracellular matrix composition and/or contractile elements in lung parenchyma. Oscillatory mechanics were analysed before and after acetylcholine (ACh) in C57BL/10, BALB/c, and A/J mice, subjected or not to ovalbumin sensitization and challenge. In controls, tissue elastance (E) and resistance (R), collagen and elastic fibres` content, and alpha-actin were higher in A/J compared to BALB/c mice, which, in turn, were more elevated than in C57BL/10. A similar response pattern was observed in ovalbumin-challenged animals irrespective of mouse strain. E and R augmented more in ovalbumin-challenged A/J [E: 22%, R: 18%] than C57BL/10 mice [E: 9.4%, R: 11 %] after ACh In conclusion, lung parenchyma remodelled differently yielding distinct in vitro mechanics according to mouse strain. (C) 2008 Elsevier B.V. All rights reserved.
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Introduction The protective effect of glutamine, as a pharmacological agent against lung injury, has been reported in experimental sepsis; however, its efficacy at improving oxygenation and lung mechanics, attenuating diaphragm and distal organ injury has to be better elucidated. In the present study, we tested the hypothesis that a single early intravenous dose of glutamine was associated not only with the improvement of lung morpho-function, but also the reduction of the inflammatory process and epithelial cell apoptosis in kidney, liver, and intestine villi. Methods Seventy-two Wistar rats were randomly assigned into four groups. Sepsis was induced by cecal ligation and puncture surgery (CLP), while a sham operated group was used as control (C). One hour after surgery, C and CLP groups were further randomized into subgroups receiving intravenous saline (1 ml, SAL) or glutamine (0.75 g/kg, Gln). At 48 hours, animals were anesthetized, and the following parameters were measured: arterial oxygenation, pulmonary mechanics, and diaphragm, lung, kidney, liver, and small intestine villi histology. At 18 and 48 hours, Cytokine-Induced Neutrophil Chemoattractant (CINC)-1, interleukin (IL)-6 and 10 were quantified in bronchoalveolar and peritoneal lavage fluids (BALF and PLF, respectively). Results CLP induced: a) deterioration of lung mechanics and gas exchange; b) ultrastructural changes of lung parenchyma and diaphragm; and c) lung and distal organ epithelial cell apoptosis. Glutamine improved survival rate, oxygenation and lung mechanics, minimized pulmonary and diaphragmatic changes, attenuating lung and distal organ epithelial cell apoptosis. Glutamine increased IL-10 in peritoneal lavage fluid at 18 hours and bronchoalveolar lavage fluid at 48 hours, but decreased CINC-1 and IL-6 in BALF and PLF only at 18 hours. Conclusions In an experimental model of abdominal sepsis, a single intravenous dose of glutamine administered after sepsis induction may modulate the inflammatory process reducing not only the risk of lung injury, but also distal organ impairment. These results suggest that intravenous glutamine may be a potentially beneficial therapy for abdominal sepsis.
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An increased risk of early pregnancy loss in women briefly exposed to high levels of ambient particulate matter during the preconceptional period was recently observed. The effects of this exposure on early embryo development are unknown. This study was designed to assess the dose-response and biological effects of diesel exhaust particles (DEP) on in vitro embryo development using the in vitro fertilization (IVF) mouse model. Zygotes obtained from superovulated mice after IVF were randomly cultured in different DEP concentrations (0, 0.2, 2, and 20 mu g/cm(2)) for 5 days and observed for their capacity to attach and develop on a fibronectin matrix until day 8. Main outcome measures included blastocyst rates 96 and 120 h after insemination, hatching discriminatory score, total cell count, proportion of cell allocation to inner cell mass (ICM) and trophectoderm (TE), ICM morphology, attachment rate and outgrowth area, apoptosis and necrosis rates, and Oct-4 and Cdx-2 expression. Multivariate analysis showed a negative dose-dependent effect on early embryo development and hatching process, blastocyst cell allocation, and ICM morphology. Although blastocyst attachment and outgrowth were not affected by DEP, a significant impairment of ICM integrity was observed in day 8 blastocysts. Cell death through apoptosis was significantly higher after DEP exposure. Oct-4 expression and the Oct-4/Cdx-2 ratio were significantly decreased in day 5 blastocysts irrespective of DEP concentration. Results suggest that DEP appear to play an important role in disrupting cell lineage segregation and ICM morphological integrity even at lower concentrations, compromising future growth and viability of the blastocyst.
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Several differences have been described between neonatal and adult immune responses. The predisposition in early life to Th2-type response or tolerance makes it a susceptible period for infections and allergic sensitization. The aim of this work was to evaluate the effects of CpG-containing oligodeoxynucleotides on neonatal and adult immunization with ovalbumin and Blomia tropicalis extract and compare the CpG effects on B and T cells of neonatal and adult mice. Mice that received CpG showed reduced immunoglobulin E (IgE) antibody production in both neonatal and adult periods, in parallel to increased IgG2a antibody levels. We observed that spleen cells of mice that received CpG in early life produced increased amounts of interferon-gamma upon anti-CD3 stimulation. Negative regulation of IgE response was more pronounced in adult than neonate mice; further, CpG decreased anaphylactic antiovalbumin IgG1 only in adults. Also, an upregulation of toll-like receptor 9 expression was detected in adult B cells, but not in neonatal, upon CpG stimuli. Neonatal B cells showed enhanced interleukin (IL)-10 expression and decreased IL-6 levels than adult B cells in response to CpG. When we analyzed in vitro activation of CD4+ T cells, an increased expression of B7 molecules on T cells in neonates was suppressed by CpG. Altogether, we verified qualitative and quantitative evidences regarding CpG effect on neonatal and adult allergens immunizations, which points to the importance of understanding neonatal immune system to establish immunomodulatory strategies for prevention of allergic diseases.
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Objectives: Injectable corticosteroids have been used in phonosurgery to prevent scarring of the vocal fold because of their effects of wound healing, and to ensure better voice quality. We histologically evaluated the effects of dexamethasone sodium phosphate infiltration on acute vocal fold wound healing in rabbits 3 and 7 days after surgically induced injury by quantification of the inflammatory reaction and collagen deposition. Methods: A standardized surgical incision was made in the vocal folds of 12 rabbits, and 0.1 mL dexamethasone sodium phosphate (4 mg/mL) was injected into the left vocal fold. The right vocal fold was not injected and served as the control. The larynges were collected 3 and 7 days after surgery. For histologic analysis, the vocal folds were stained with hematoxylin-eosin for quantification of the inflammatory response and with picrosirius red for qunatification of collagen depostion. Results: There was no quantitative difference in the inflammatory response between vocal folds injected with the corticosteroid and control vocal folds. However, the rate of collage deposition was significantly lower in the corticosteroid-treated group at 3 and 7 days after injury (p = 0.002). Conclusions: The present results suggest that dexamethasone reduces collagen depostion during acute vocal fold wound healing.
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Introduction: Recruitment maneuvers (RMs) seem to be more effective in extrapulmonary acute lung injury (ALI), caused mainly by sepsis, than in pulmonary ALI. Nevertheless, the maintenance of adequate volemic status is particularly challenging in sepsis. Since the interaction between volemic status and RMs is not well established, we investigated the effects of RMs on lung and distal organs in the presence of hypovolemia, normovolemia, and hypervolemia in a model of extrapulmonary lung injury induced by sepsis. Methods: ALI was induced by cecal ligation and puncture surgery in 66 Wistar rats. After 48 h, animals were anesthetized, mechanically ventilated and randomly assigned to 3 volemic status (n = 22/group): 1) hypovolemia induced by blood drainage at mean arterial pressure (MAP)approximate to 70 mmHg; 2) normovolemia (MAP approximate to 100 mmHg), and 3) hypervolemia with colloid administration to achieve a MAP approximate to 130 mmHg. In each group, animals were further randomized to be recruited (CPAP = 40 cm H(2)O for 40 s) or not (NR) (n = 11/group), followed by 1 h of protective mechanical ventilation. Echocardiography, arterial blood gases, static lung elastance (Est, L), histology (light and electron microscopy), lung wet-to-dry (W/D) ratio, interleukin (IL)-6, IL-1 beta, caspase-3, type III procollagen (PCIII), intercellular adhesion molecule-1 (ICAM-1), and vascular cell adhesion molecule-1 (VCAM-1) mRNA expressions in lung tissue, as well as lung and distal organ epithelial cell apoptosis were analyzed. Results: We observed that: 1) hypervolemia increased lung W/D ratio with impairment of oxygenation and Est, L, and was associated with alveolar and endothelial cell damage and increased IL-6, VCAM-1, and ICAM-1 mRNA expressions; and 2) RM reduced alveolar collapse independent of volemic status. In hypervolemic animals, RM improved oxygenation above the levels observed with the use of positive-end expiratory pressure (PEEP), but increased lung injury and led to higher inflammatory and fibrogenetic responses. Conclusions: Volemic status should be taken into account during RMs, since in this sepsis-induced ALI model hypervolemia promoted and potentiated lung injury compared to hypo-and normovolemia.
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Background Livedoid vasculopathy (LV) is a chronic idiopathic disease characterized by painful purpuric macules on lower extremities. Its exact aetiology remains uncertain, but thrombotic and microcirculatory phenomena have been implicated as possible pathogenic factors. Objectives To assess prospectively the frequency of thrombophilia and to verify the effectiveness of anticoagulant therapy among LV patients. Methods Thirty-four LV patients were tested for prothrombin time, activated partial thromboplastin time, antithrombin activity, protein C and S activity, anticardiolipin antibodies, lupus anticoagulant, prothrombin gene mutation, factor V Leiden mutation, methylenetetrahydrofolate reductase mutation, plasma homocysteine and fibrinogen. Thirteen of these patients were treated with anticoagulant drugs (either warfarin or heparin). Results Of 34 patients, 18 (52%) presented laboratory abnormalities of procoagulant conditions. Positive treatment response to anticoagulant therapy was observed in 11 patients. Improvement of pain was obtained in 1-3 weeks, an average of 1.8 week. Complete healing of the lesions was observed in about 2.3 months. Remission was sustained even after treatment interruption and lasted an average 7.8 months. No severe adverse effects were noticed. Conclusion The authors suggest all patients with diagnosis of LV to be investigated for thrombophilic status. Anticoagulant drugs were well tolerated and seemed to be effective in treating not only LV symptoms but also its ulcerations.
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We investigated the effects of salbutamol on the markers of epithelial function in a murine model of chronic allergic pulmonary inflammation by recording the ciliary beat frequency (CBF) and the transepithelial potential difference (PD) in vivo. Mice were sensitized and received four challenges of ovalbumin (OVA group) or 0.9% saline (control group). Forty-eight hours after the 4th inhalation, we observed eosinophilia in the bronchoalveolar lavage and epithelium remodeling with stored acid mucus in the OVA group (P < 0.001). No difference in the baseline CBF was noticed between the groups; however, the OVA group had a significantly lower baseline PD (P = 0.013). Salbutamol increased the CBF in all groups studied, and the dose response curve to salbutamol increased the PD in the OVA group from 10(-4) M to 10(-2) M. We suggest that salbutamol affects the CBF and the depth of the periciliary layer, which, in great part, determines the ability of the cilia to propel the mucus layer. This effect may have a positive impact on airway mucociliary transport in asthma and may have clinical implications. (C) 2011 Elsevier B.V. All rights reserved.