Estudo do efeito dos metabólitos do benzeno e tolueno sobre as mitocôndris cerebrais e hepáticas de ratos

Aim: The aim of this work was to investigate the hypothesis that catechol and 3MC inhibit FADH2-linked basal respiration in mitochondria isolated from rat liver and brain homogenates. Moreover, catechol ability to induce DNA damage in rat brain cells through the comet assay (alkaline single-cell gel electrophoresis assay) was also observed. Methods: Two different catechols were evaluated: pirocatechol (derived from benzene) and 3-methylcatechol (derived from toluene); rat liver and brain homogenates were incubated with 1mM catechol at pH 7.4 for up to 30 minutes. After that, mitochondrial fractions were isolated by differential centrifugation. Basal oxygen uptake was measured using a Clark-type electrode after the addition of 10 mM sodium succinate for a period of 12 minutes. In additional experiments, rat brain cells were treated with 1, 5 and 10mM pirocatechol for up to 20 minutes at 37º C, and submitted to electrophoresis. Results: Catechols (pirocatechol and 3methylcatechol) induced a time-dependent partial inhibition of FADH2-linked basal mitochondrial respiration. Indeed, pirocatechol was able to produce a dosedependent DNA oxidative damage in rat brain cells by 2 and 4 injury levels. These results suggest that reactive oxygen species generated by the oxidation of catechols, induced an impairment on mitochondrial respiration and a DNA damage, which might be related to their citotoxicity. Conclusion: Catechols produced an inhibition of basal respiration associated to FADH2 in isolated liver and brain mitochondria; 3-methylcatechol, at the same concentration, produced similar toxicity in the mitochondrial model. Indeed, pirocatechol induced a DNA damage in rat brain cells, mainly observed in comets formation and consequent DNA degradation

Efeitos do treinamento muscular inspiratório domiciliar sobre a atividade eletromiográfica dos músculos respiratórios em asmáticos: estudo piloto

Asthma treatment aims to achieve and maintain the control of the disease for prolonged periods. Inspiratory muscle training (IMT) may be an alternative in the care of patients with asthma, and it is used as a complementary therapy to the pharmacological treatment. Thus, the aim of this study was to investigate the effects of a domiciliary program of IMT on the electromyographic activity of the respiratory muscles in adults with asthma. This is a clinical trial in which ten adults with asthma and ten healthy adults were randomized into two groups (control and training). The electrical activity of inspiratory muscles (sternocleidomastoid (ECM) and diaphragm) was obtained by a surface electromyography. Furthermore, we assessed lung function (spirometry), maximal inspiratory pressure - MIP - (manometer). The functional capacity was evaluated by six minute walk test. Participants were assessed before and after the IMT protocol of 6 weeks with POWERbreathe® device. The training and the control groups underwent IMT with 50% and 15 % of MIP, respectively. The sample data were analyzed using SPSS 20.0, attributing significance of 5 %. Were used t test, ANOVA one way and Pearson correlation. It was observed an increase in MIP, after IMT, in both training groups and in healthy sham group (P < 0.05), which was accompanied by a significant increase in ECM activity during MIP in healthy training group (1488 %) and in asthma training group (ATG) (1186.4%). The ATG also showed a significant increase in diaphragm activity in basal respiration (48.5%). Functional capacity increased significantly in the asthma sham group (26.5 m) and in the asthma training group (45.2 m). These findings suggest that IMT promoted clinical improvements in all groups, especially the ATG, which makes it an important complementary treatment for patients with asthma

Efeitos da respiração em freno-labial sobre os volumes pulmonares e o padrão de hiperinsuflação dinâmica em pacientes com asma

Objectives: To evaluate how to develop dynamic hyperinflation (DH) during exercise, the influence of pursed-lip breathing in (PLB) on breathing pattern and operating volume in patients with asthma. Methods: We studied 12 asthmatic patients in three moments: (1) anthropometry and spirometry, (2) submaximal incremental cycle ergometer test in spontaneous breathing and (3), submaximal incremental test on a cycle ergometer with PLB using the Opto-electronic plethysmography. Results: Evaluating the end-expiratory lung volume (EEV) during submaximal incremental test in spontaneous breathing, patients were divided into euvolume and hyperinflated. The RFL has increased significantly, the variation of the EEV group euvolume (1.4L) and decreased in group hyperinflated (0.272L). In group volume observed a significant increase of 140% in Vt at baseline, before exercise, comparing the RFL and spontaneous breathing. Hyperinflated group was observed that the RFL induced significant increases of Vt at all times of the test incremental baseline, 50%, 100% load and 66% recovery, 250%, 61.5% and 66% respectively. Respiratory rate decreased significantly with PLB at all times of the submaximal incremental test in the group euvolume. The speed of shortening of inspiratory muscles (VtRcp/Ti) in the hyperinflated increased from 1.6 ± 0.8L/s vs. 2.55 ± 0.9L/s, whereas in the RFL euvolume group ranged from 0.72 ± 0.31L/s vs. 0.65 ± 0.2L/s. The velocity of shortening of the expiratory muscles (VtAb/Te) showed similarity in response to RFL. In group hyperinflated varied vs. 0.89 ± 0.47 vs. 0.80 ± 0.36 and ± 1.17 ± 1L vs. 0.78 ± 0.6 for group euvolume. Conclusion: Different behavior in relation to EEV in patients with moderate asthma were observed, the HD and decreased EEV in response to exercise. The breathing pattern was modulated by both RFL performance as at home, making it more efficient