Microvascular oxygen extraction during maximal isometric contraction in patients with chronic obstructive pulmonary disease / Extração microvascular de oxigênio durante contração isométrica máxima em pacientes com DPOC não hipoxêmicos

Abstract Introduction: COPD presents decrease in oxidative metabolism with possible losses of cardiovascular adjustments, suggesting slow kinetics microvascular oxygen during intense exercise. Objective: To test the hypothesis that chronic obstructive pulmonary disease (COPD) patients have lower muscle performance in physical exercise not dependent on central factors, but also greater muscle oxygen extraction, regardless of muscle mass. Methods: Cross-sectional study with 11 COPD patients and nine healthy subjects, male, paired for age. Spirometry and body composition by DEXA were evaluated. Muscular performance was assessed by maximal voluntary isometric contraction (MVIC) in isokinetic dynamometer and muscle oxygen extraction by the NIRS technique. Student t-test and Pearson correlation were applied. A significance level of p<0.05 was adopted. Results: Patients had moderate to severe COPD (FEV1 = 44.5 ± 9.6% predicted; SpO2 = 94.6 ± 1.6%). Lean leg mass was 8.3 ± 0.9 vs. 8.9 ± 1.0 kg (p =0.033), when comparing COPD and control patients, respectively. The decreased muscle oxygen saturation corrected by muscle mass was 53.2% higher (p=0.044) in the COPD group in MVIC-1 and 149.6% higher (p=0.006) in the MVIC-2. Microvascular extraction rate of oxygen corrected by muscle mass and total work was found to be 114.5% higher (p=0.043) in the COPD group in MVIC-1 and 210.5% higher (p=0.015) in the MVIC-2. Conclusion: COPD patients have low muscle performance and high oxygen extraction per muscle mass unit and per unit of work. The high oxygen extraction suggests that quantitative and qualitative mechanisms can be determinants of muscle performance in patients with COPD.

Resumo Introdução: DPOC (doença pulmonar obstrutiva crônica) apresenta diminuição no metabolismo oxidativo com prejuízos dos ajustes cardiovasculares, sugerindo cinética de oxigênio microvascular lenta durante exercício intenso. Objetivo: Testar hipótese que pacientes com DPOC apresentam não só menor performance muscular em exercício físico não dependente dos fatores centrais, mas também maior extração muscular de O2 independentemente da massa muscular. Métodos: Estudo transversal, 11 pacientes DPOC e 9 indivíduos saudáveis, gênero masculino, pareados pela idade. Avaliado espirometria, composição corporal, performance muscular por contração isométrica voluntária máxima (CIVM) em dinamometria isocinética e extração muscular de oxigênio pela técnica de NIRS. Teste t-Student e correlação de Pearson foram aplicados. Adotado p<0,05 como nível de significância. Resultados: Pacientes com DPOC moderado para grave (VEF1 = 44,5 ± 9,6 % predito; SpO2 = 94,6 ± 1,6 %). Massa magra do membro inferior foi de 8,3 ± 0,9 vs. 8,9 ± 1,0 Kg (p= ,033), comparando DPOC e controle respectivamente. A redução saturação muscular de O2 corrigido pela massa muscular foi 53,2 % maior (p=0,044) no grupo DPOC na CIVM-1 e 149,6% maior (p=0,006) na CIVM-2. A taxa de extração microvascular de O2 corrigida pela massa muscular e trabalho total apresentou-se 114,5% maior (p=0,043) no grupo DPOC na CIVM-1 e 210,5% maior (p= 0,015) na CIVM-2. Conclusão: Pacientes com DPOC apresentam baixa performance muscular e alta extração de O2 por unidade de massa muscular e por unidade de trabalho. A elevada extração de O2 sugere que mecanismos quantitativos e qualitativos podem ser determinantes da performance muscular em pacientes com DPOC.

Cross-cultural adaptation to Brazilian Portuguese of the Michigan Neuropathy Screening Instrument: MNSI-Brazil.

Since 1994, the University of Michigan Diabetes Research and Training Center proposed an instrument to measure neuropathies not yet adapted to use in Brazil. Then, this study aimed to adapt cross-culturally the Michigan Neuropathy Screening Instrument (MNSI) into Brazilian Portuguese, verifying its reliability. Thirty diabetic patients were initially evaluated with the adapted version after completed the essential steps to accomplish the cross-cultural adaptation. Twenty-two of them completed the procedures to repeat the measured scores after day 1 (trial 0). The repeated measurements were tested at days 2 or 3 (trial 1) by another rater (inter-rater reliability) and retested at day 20 (trial 2) by one of the attended raters (inter-test reliability). There were not great semantics, linguistics or cultural differences between two versions and excellent reliability was confirmed by intra-class correlation coefficient above 0.840. It was concluded that MNSI in the Brazilian version is reliable and it is ready to use.

Cross-cultural adaptation to Brazilian Portuguese of the Michigan Neuropathy Screening Instrument: MNSI-Brazil / Adaptação transcultural para o português brasileiro do Michigan Neuropathy Screening Instrument: MNSI-Brasil

ABSTRACT Since 1994, the University of Michigan Diabetes Research and Training Center proposed an instrument to measure neuropathies not yet adapted to use in Brazil. Then, this study aimed to adapt cross-culturally the Michigan Neuropathy Screening Instrument (MNSI) into Brazilian Portuguese, verifying its reliability. Thirty diabetic patients were initially evaluated with the adapted version after completed the essential steps to accomplish the cross-cultural adaptation. Twenty-two of them completed the procedures to repeat the measured scores after day 1 (trial 0). The repeated measurements were tested at days 2 or 3 (trial 1) by another rater (inter-rater reliability) and retested at day 20 (trial 2) by one of the attended raters (inter-test reliability). There were not great semantics, linguistics or cultural differences between two versions and excellent reliability was confirmed by intra-class correlation coefficient above 0.840. It was concluded that MNSI in the Brazilian version is reliable and it is ready to use.

RESUMO Desde 1994, o Centro de Treinamento e Pesquisa em Diabetes da Universidade de Michigan propôs um instrumento não ainda adaptado para uso no Brasil para mensurar neuropatias. O objetivo deste estudo foi adaptar transculturalmente o Michigan Neuropathy Screening Instrument (MNSI) para o Português brasileiro, verificando sua confiabilidade. Trinta pacientes diabéticos foram inicialmente avaliados pela versão adaptada depois de completados os passos essenciais para finalizar a adaptação transcultural. Vinte e dois deles completaram os procedimentos para repetir os escores medidos depois do dia 1 (ensaio 0). As medidas repetidas foram testadas nos dias 2 ou 3 (ensaio 1) por outro examinador (confiabilidade interexaminador) e retestadas no dia 20 (ensaio 2) por um dos examinadores participantes (confiabilidade interteste). Não existiam diferenças semânticas, linguísticas ou culturais entre as duas versões e excelente confiabilidade foi confirmada pelo coeficiente de correlação intra-classe acima de 0,840. Conclui-se que o MNSI na versão brasileira é confiável e está pronto para uso.

High oxygen extraction and slow recovery of muscle deoxygenation kinetics after neuromuscular electrical stimulation in COPD patients.

PURPOSE: It was hypothesized that patients with chronic obstructive pulmonary disease (COPD) would exhibit a slow muscle deoxygenation (HHb) recovery time when compared with sedentary controls. METHODS: Neuromuscular electrical stimulation (NMES 40 and 50 mA, 50 Hz, 400 µs) was employed to induce isometric contraction of the quadriceps. Microvascular oxygen extraction (µO2EF) and HHb were estimated by near-infrared spectroscopy (NIRS). Recovery kinetic was characterized by measuring the time constant Tau (HHb-τ). Torque and work were measured by isokinetic dynamometry in 13 non-hypoxaemic patients with moderate-to-severe COPD [SpO2 = 94.1 ± 1.6 %; FEV1 (% predict) 48.0 ± 9.6; GOLD II-III] and 13 age- and sex-matched sedentary controls. RESULTS: There was no desaturation in either group during NMES. Torque and work were reduced in COPD versus control for 40 and 50 mA [torque (Nm) 50 mA = 28.9 ± 6.9 vs 46.1 ± 14.2; work (J) 50 mA = 437.2 ± 130.0 vs. 608.3 ± 136.8; P < 0.05 for all]. High µO2EF values were observed in the COPD group at both NMES intensities (corrected by muscle mass 50 mA = 6.18 ± 1.1 vs. 4.68 ± 1.0 %/kg; corrected by work 50 mA = 0.12 ± 0.05 vs. 0.07 ± 0.02 %/J; P < 0.05 for all). Absolute values of HHb-τ (50 mA = 31.11 ± 9.27 vs. 18.08 ± 10.70 s), corrected for muscle mass (50 mA 3.80 ± 1.28 vs. 2.05 ± 1.45 s/kg) and corrected for work (50 mA = 0.08 ± 0.04 vs. 0.03 ± 0.02 s/J) were reduced in COPD (P < 0.05 for all). The variables behaviour for 40 mA was similar to those of 50 mA. CONCLUSIONS: COPD patients exhibited a slower muscle deoxygenation recovery time after NMES. The absence of desaturation, low torque and work, high µO2EF and high values for recovery time corrected by muscle mass and work suggest that intrinsic muscle dysfunction has an impact on muscle recovery capacity.

Glytube: a conical tube and parafilm M-based method as a simplified device to artificially blood-feed the dengue vector mosquito, Aedes aegypti.

Aedes aegypti, the main vector of dengue virus, requires a blood meal to produce eggs. Although live animals are still the main blood source for laboratory colonies, many artificial feeders are available. These feeders are also the best method for experimental oral infection of Ae. aegypti with Dengue viruses. However, most of them are expensive or laborious to construct. Based on principle of Rutledge-type feeder, a conventional conical tube, glycerol and Parafilm-M were used to develop a simple in-house feeder device. The blood feeding efficiency of this apparatus was compared to a live blood source, mice, and no significant differences (p = 0.1189) were observed between artificial-fed (51.3% of engorgement) and mice-fed groups (40.6%). Thus, an easy to assemble and cost-effective artificial feeder, designated "Glytube" was developed in this report. This simple and efficient feeding device can be built with common laboratory materials for research on Ae. aegypti.

Electronic structure and optical properties of an alternated fluorene-benzothiadiazole copolymer: interplay between experimental and theoretical data.

The donor-acceptor copolymer containing benzothiadiazole (electron acceptor), linked to functionalized fluorene (electron donor), [poly[9,9-bis(3'-(tert-butyl propanoate))fluorene-co-4,7-(2,1,3-benzothiadiazole)] (LaPPS40), was synthesized through the Suzuki route. The polymer was characterized by scanning electron microscopy, gel permeation chromatography, NMR, thermal analysis, cyclic voltammetry, X-ray photoelectron spectroscopy, UV-vis spectrometry, and photophysical measurements. Theoretical calculations (density functional theory and semiempirical methodologies) used to simulate the geometry of some oligomers and the dipole moments of molecular orbitals involved were in excellent agreement with experimental results. Using such data, the higher energy absorption band was attributed to the π-π* (S(0) → S(4)) transition of the fluorene units and the lower lying band was attributed to the intramolecular (ICT) (S(0) → S(1)) charge transfer between acceptor (benzothiadiazole) and donor groups (fluorene) (D-A structure). The ICT character of this band was confirmed by its solvatochromic properties using solvents with different dielectric properties, and this behavior could be well described by the Lippert-Mataga equation. To explain the solvatochromic behavior, both the magnitude and orientation of the dipole moments in the electronic ground state and in the excited state were analyzed using the theoretical data. According to these data, the change in magnitude of the dipole moments was very small for both transitions but the spatial orientation changed remarkably for the lower energy band ascribed to the ICT band.