High Final Energy of Low-Level Gallium Arsenide Laser Therapy Enhances Skeletal Muscle Recovery without a Positive Effect on Collagen Remodeling.

The aim of this study was to evaluate the effects of a Gallium Arsenide (GaAs) laser, using a high final energy of 4.8 J, during muscle regeneration after cryoinjury. Thirty Wistar rats were divided into three groups: Control (C, n = 10); Injured (I, n = 10) and Injured and laser treated (Injured/LLLT, n = 10). The cryoinjury was induced in the central region of the tibialis anterior muscle (TA). The applications of the laser (904 nm, 50 mW average power) were initiated 24 h after injury, at energy density of 69 J cm(-1) for 48 s, for 5 days, to two points of the lesion. Twenty-four hours after the final application, the TA muscle was removed and frozen in liquid nitrogen to assess the general muscle morphology and the gene expression of TNF-α, TGF-ß, MyoD, and Myogenin. The Injured/LLLT group presented a higher number of regenerating fibers and fewer degenerating fibers (P < 0.05) without changes in the collagen remodeling. In addition, the Injured/LLLT group presented a significant decrease in the expression of TNF-α and myogenin compared to the injured group (P < 0.05). The results suggest that the GaAs laser, using a high final energy after cryoinjury, promotes muscle recovery without changing the collagen remodeling in the muscle extracellular matrix.

Differential morphofunctional characteristics and gene expression in fast and slow muscle of rats with monocrotaline-induced heart failure.

Heart failure (HF) is characterized by limited exercise tolerance, skeletal muscle atrophy, a shift toward fast muscle fiber, and myogenic regulatory factor (MRF) changes. Reactive oxygen species (ROS) also contribute to target organ damage in this syndrome. In this study, we investigated and compared morphofunctional characteristics and gene expression in Soleus (SOL--oxidative and slow twitching muscle) and in Extensor Digitorum Longus (EDL--glycolytic and fast twitching muscle) during HF. Two groups of rats were used: control (CT) and heart failure (HF), induced by a single injection of monocrotaline. MyoD and myogenin gene expression were determined by RT-qPCR, and MHC isoforms by SDS-PAGE; muscle fiber type frequency and cross sectional area (CSA) were analyzed by mATPase. A biochemical study was performed to determine lipid hydroperoxide (LH), glutathione peroxidase (GSH-Px), and superoxide dismutase (SOD); myography was used to determine amplitude, rise time, fall time, and fatigue resistance in both muscles. HF showed SOL and EDL muscle atrophy in all muscle fiber types; fiber frequency decreased in type IIC and muscle contraction fall time increased only in SOL muscle. Myogenin mRNA expression was lower in SOL and myoD decreased in HF EDL muscle. LH increased, and SOD and GSH-Px activity decreased only in HF SOL muscle. HF EDL muscle did not present changes in MHC distribution, contractile properties, HL concentration, and antioxidant enzyme activity. In conclusion, our results indicate that monocrotaline induced HF promoted more prominent biochemical, morphological and functional changes in SOL (oxidative and slow twitching muscle). Although further experiments are required to better determine the mechanisms involved in HF pathophysiology, our results contribute to understanding the muscle-specific changes that occur in this syndrome.

Orientação sobre postura sentada em trabalhadores administrativos: comparação de procedimentos educativos / Orientation on position seated in administrative workers: comparison of educative procedures

Propor-se verificar as mudanças de conhecimentos teóricos sobre postura sentada a partir de dois procedimentos educacionais (auto-instrucional e expositiva associadas às oficinas de educação). Realizou-se um estudo quase-experimental, com 94 funcionários administrativos de uma empresa pública, alocados em três grupos pora mostragem aleatória simples e sem reposição. O grupo de aulas/oficinas, com 32 indivíduos; do manual auto-instrucional, com 28;o controle, com 34. Mensurou-se os conhecimentos sobre postura sentada por meio de um questionário, no início e após 30 dias do término dos programas. Utilizou-se a estatística descritiva e a técnica de variância não-paramétrica para o modelo de medidas repetidas em três grupos independentes...

It was proposed to verify the theoretical knowledge changes concerning sitting posture through two educational programs (self-instructional and expositive classes associated with educational workshops). A semi-experimental study was developed with 94 management employees of a public company divided into three groups according to simple randomized sampling with no participant replacement. There were 32 people in the classes/workshops group; 28 in the self-instructional manual group and 34 in the control group. Knowledge on sitting posture was measured, by means of the Questionnaire, at the beginning of the program and 30 days later. It was used descriptive statistics and non-parametric variation technique for repeated measures model in three independent groups...