In the present study, a chemiresistor sensor based on a poly­(Bismarck Brown Y)-reduced graphene oxide nanocomposite was developed to analyze the respiratory capacity of the constituent complexes of the electron transport chain. The sensorial platform was characterized using electrochemical impedance spectroscopy, and oxygen detection was accomplished by measuring the resistive properties of the sensor at fixed AC frequency. The impedance decreased significantly in response to small variations of the O2 concentrations tested up to saturation of the electrolyte solution with molecular oxygen. The resistive response of the sensor at 0.1 Hz was linear over the oxygen concentration range from 1.17 × 10–5 mol L–1 to 1.02 × 10–3 mol L–1, with a detection limit of 3.60 × 10–7 mol L–1. Using the new O2 sensing platform, we monitored gradients in static cultures of adherent cells exposed to graded oxygen both at rest and upon metabolic stimulation. Under high dissolved oxygen conditions, the respiration of resting cells dictated that local O2 was moderately reduced, while cell metabolic stimulation triggered a major redistribution of O2. The usefulness of the developed sensor was demonstrated by continuous monitoring of mitochondrial oxygen consumption in various biologic applications.

Exposure to secondhand cigarette smoke is associated with the development of diverse diseases. Resistance training has been considered one of the most useful tools for patients with pulmonary disease, improving their quality of life. This study aimed to evaluate the effect of resistance training (RT) on the prevention of thickening of the right ventricle wall of rats exposed to secondhand cigarette smoke. Thirty-two Wistar rats were divided into four groups: Control (C), Smoker (S), Exercised (E) and Exercised Smoker (ES). The smoker groups were exposed to the smoke of four cigarettes for 30 min, twice daily, five days a week, for 16 weeks. The exercised groups climbed on a vertical ladder with progressive load, once a day, five days a week, for 16 weeks. The heart, trachea, lung, liver and gastrocnemius muscle were removed for histopathological analysis. Pulmonary emphysema (S and ES vs C and E, P < 0.0001) and pulmonary artery thickness enlargement (S vs C and E, P = 0.003, ES vs C, P = 0.003) were detected in the smoking groups. There was an increase in the right ventricle thickness in the S group compared with all other groups (P < 0.0001). An increase in resident macrophages in the liver was detected in both smoking groups compared with the C group (P = 0.002). Additionally, a relevant reduction of the diameter of the muscle fibers was detected only in ES compared with the C, S and E groups (P = 0.0002), impairing, at least in part, the muscle mass in exercised smoking rats. Therefore, it was concluded that resistance training prevented the increase of thickness of the right ventricle in rats exposed to secondhand cigarette smoke, but it may be not so beneficial for the skeletal muscle of smoking rats.

RESUMOIntrodução: Os músculos isquiotibiais estão expostos ao encurtamento devido à vida sedentária de algumas pessoas e ao longo período de tempo em que os indivíduos passam sentados. Objetivo: Verificar a incidência de encurtamento muscular de isquiotibiais em adultos jovens entre 18 e 25 anos de idade. Método: Estudo transversal, com 103 participantes que foram avaliados pela goniometria. Os pacientes foram posicionados em decúbito dorsal, membro inferior testado com quadril posicionado em 90° de flexão, foi realizada extensão lenta e passiva do joelho pelo avaliador até o momento em que o indivíduo referiu desconforto nos isquiotibiais, para assim verificar o ângulo poplíteo. Resultados: Após avaliação 80,6% dos participantes apresentaram encurtamento dos isquiotibiais, desses 79,5% mulheres e 20,5% homens. Conclusão: Conclui-se que grande percentual dos adultos jovens avaliados apresentaram encurtamento de isquiotibiais, e existe necessidade de orientação para esses indivíduos para proporcionar mais flexibilidade muscular e qualidade de vida. Palavras Chaves: Encurtamento, isquiotibiais, Adultos jovens. ANALYSIS OF HAMSTRING MUSCLE SHORTENING IN YOUNG ADULTS FROM 18 TO 25 YEARS OLDABSTRACT Introduction: The hamstring muscles are exposed to shortening because the sedentary lifestyle of some people the over time that individuals spend sitting. Objective: To determine the incidence of hamstring muscle shortening in young adults from 18 to 25 years old. Methods: Cross-sectional study with 103 participants who were evaluated by goniometry. The participants were positioned in supine, lower limb tested with hip positioned in 90° of flexion, was performed slowly and passive knee extension by the evaluator until such time that the individual referred discomfort in the hamstring, so as to check the popliteal angle. Results: After evaluation 80.9% of the participants had showed shortened hamstrings, of those 79.5% women and 20.5% men. Conclusion: We conclude that a large percentage of young adults evaluated had shortened hamstrings, there is need for guidance for these young adults to provide more muscle flexibility and quality of life.

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