Impacto do treinamento resistido na força e hipertrofia muscular em HIV-soropositivos / Impact of resistance training on strength and muscle hypertrophy in HIV-seropositive

O presente estudo investigou o efeito de 24 semanas de treinamento resistido (TR) sobre a força e hipertrofia muscular de pacientes HIV-soropositivos. Participaram deste estudo 45 voluntários submetidos à terapia antirretroviral fortemente ativa (HAART), destes, 23 realizaram 3 sessões semanais, com 10 repetições a 80% 1RM. O teste de 1RM foi realizado de acordo com a metodologia proposta por Kraemer e Fry (1995), para estimativa da hipertrofia muscular adotou-se as equações de Frisancho (1984). Em comparação aos valores, o TR melhorou a força de 1RM nos exercícios de agachamento em 49% (21,0±4,9 vs. 31,2±5,1; P=0,001), supino reto em 13% (34,3±8,1 vs. 39,8±9,4; P=0,04), cadeira extensora em 34,1% (26,3±7,1 vs. 37,1±6,6; P=0,01), tríceps em 51% (22,9±4,0 vs. 38,3±4,9; P=0,001), pulley costas em 31,5% (31,7±3,9 vs. 41,7±4,4; P=0,01), cadeira flexora em 37,2% (18,9±3,4 vs. 27,3±3,2; P=0,01) e rosca bíceps em 60% (27,9±6,9 vs. 40,4±4,5; P=0,001). Não foram observadas diferenças (P<0,05) entre os valores basais e finais para o grupo controle. Observou-se aumento significativo (P<0,05) na área muscular do braço isenta de massa óssea, no grupo TR (52,8±14,5 cm²) em relação ao controle (39,5±12,4 cm²). Ademais, o TR resultou em significativa (P<0,05) redução da glicemia sanguínea de jejum (96,5±18,3 vs. 90,5±12,6), pressão arterial sistólica (126,3±14,3 vs. 120,0±10,0) e circunferência de cintura (83,0±12,5 vs. 80,6±10,2). Conclui-se que seis meses de TR resultaram em melhora na força e hipertrofia, ademais, o treinamento aplicado contribuiu para a regulação das variáveis metabólicas dos pacientes. Uma vez que a HAART é inevitável ao HIV-soropositivo, recomenda-se que o exercício físico seja realizado no intuito de dirimir os efeitos colaterais advindos desta terapia.

The aim of this study was to investigate the effect of 24 weeks of resistance training (RT) on the strength and muscle hypertrophy in patients with HIV-seropositive. Participated in the study 45 subjects undergoing highly active antiretroviral therapy (HAART). They were divided into two groups: control (n=22) and RT (n=23). The RT group realized three sessions, with 10 repetitions at 80% of 1MR. The MR tests were performed pre and post 24 weeks according to Kraemer and Fry (1995) and the equations proposed by Frisancho (1984) were adopted to estimate bone-free upper arm muscle area. Compared to baseline, the RT improved the strength of 1MR in the squat exercise at 49% (21.0±4.9 vs. 31.2±5.1; P=0.001), bench press by 13% (34.3±8.1 vs. 39.8±9.4, P=0.04), leg extension in 34.1% (26.3±7.1 vs. 37.1±6.6, P=0.01), triceps in 51% (22.9±4.0 vs. 38.3±4.9, P=0.001), pulley in 31.5% (31.7±3.9 vs. 41.7±4.4, P=0.01), leg curl in 37.2% (18.9±3.4 vs. 27.3±3.2, P=0.01) and biceps in 60% (27.9±6.9 vs. 40.4±4.5, P=0.001); there were no significant differences between baseline and final at control. The Bone-free upper arm muscle area at RT group (52.8±14.5 cm²) was significant increased (P<0.05) comparing to control (39.5±12.4 cm²). Moreover, the RT resulted in significant reduction (P<0.05) in fasting blood glucose (96.5±18.3 vs. 90.5±12.6, P<0.05), systolic blood pressure (126.3±14.3 mmHg vs. 120.0±10.0 mmHg) and waist circumference (83.0±12.5 cm vs. 80.6±10.2 cm). We conclude that six months of RT resulted in improvement in strength and hypertrophy; in addition, this training contributed to regulate the metabolic variables from these patients. Since the HAART is inevitable to HIV-seropositive, It's recommended that physical exercise be realized to minimize the side effects from this therapy.

Estresse oxidativo: conceito, implicações e fatores modulatórios / Oxidative stress: concept, implications and modulating factors

O estresse oxidativo decorre de um desequilíbrio entre a geração de compostos oxidantes e a atuação dos sistemas de defesa antioxidante. A geração de radicais livres e/ou espécies reativas não radicais é resultante do metabolismo de oxigênio. A mitocôndria, por meio da cadeia transportadora de elétrons, é a principal fonte geradora. O sistema de defesa antioxidante tem a função de inibir e/ou reduzir os danos causados pela ação deletéria dos radicais livres e/ou espécies reativas não radicais. Esse sistema, usualmente, é dividido em enzimático (superóxido dismutase, catalase e glutationa peroxidase) e não-enzimático. No último caso, é constituído por grande variedade de substâncias antioxidantes, que podem ter origem endógena ou dietética. Objetivou-se revisar os principais mecanismos de geração de radicais livres, bem como a ação dos agentes mais relevantes do sistema de defesa antioxidante, ressaltando suas implicações sobre os marcadores do estresse oxidativo. Também serão abordados os principais fatores exógenos moduladores do estresse oxidativo.

There is evidence that oxidative stress, defined as a persistent imbalance between the production of highly oxidative compounds and antioxidant defenses, leads to tissue damage. Oxygen metabolism generates free radicals and/or non-radical reactive oxygen species. The mitochondria, through the electron transport chain, are the main generator of these species. The antioxidant defense system has the function of inhibiting and/or reducing the damage caused by the deleterious free radicals and/or non-radical reactive oxygen species. This system is divided into enzymatic (superoxide dismutase, catalase and glutathione peroxidase), and nonenzymatic. The nonenzymatic system consists of a variety of antioxidant substances, which may be endogenous or dietary. This study proposed to review the main mechanisms of reactive oxygen species generation and the role of the most relevant agents of the antioxidant defense system on the biomarkers of oxidative stress. The main exogenous factors that modulate oxidative stress will also be discussed.

Dengue: a review of the laboratory tests a clinician must know to achieve a correct diagnosis

Dengue is the most important disease caused by an arbovirus (1, 2, 3 and 4 serotypes) worldwide, especially in the tropical and sub-tropical regions. Its clinical manifestations range from asymptomatic infections to a severe disease characterized by hemorrhage and shock. The incidence of dengue virus activity in the Americas has substantially increased from 1980 to 1994. In Brazil, the increase in the incidence of dengue is especially linked to the dissemination of Aedes aegypti. Thus, a rapid and accurate dengue diagnosis is of paramount importance for effective control of dengue outbreaks [8]. Five serological tests have been used for the diagnosis of dengue infection: hemagglutination-inhibition (HI), complement fixation (CF), neutralization test (NT), immunoglobulin M (IgM) capture enzyme linked immunosorbent assay (MAC-ELISA) and indirect immunoglobulin G ELISA. The limitations of these techniques are the high cross-reactivity observed with these tests. Four methods of viral isolation have been routinely used for dengue viruses: intracerebral inoculation of newborn mice, inoculation on mammalian cell cultures, intrathoracic inoculation of adult mosquitoes, and inoculation on mosquito cell cultures. In recent years, several new diagnostic techniques have been developed and have proven very useful in dengue diagnosis, such as: nucleic and acid hybridization, RT-PCR. Currently, dengue diagnosis is based on serology, viral isolation and RNA detection. Enzyme-linked immunosorbent assays (ELISA) are still the most widely used technique for serological diagnosis, but they do not identify the dengue virus serotype responsible for the current infection, so molecular techniques may soon assume a very important role in dengue diagnosis. RT-PCR is definitely the most satisfactory test that can be used on these infections, since it has been shown to be able to detect dengue viruses up to the 10th day after the onset of the symptoms.