Oxidative status of the myocardium in response to different intensities of physical training.

The intensity of exercise determines the metabolic pathway and the energetic substrate that is spent. Our study sought to identify the effects of different intensities of swimming on myocardial oxidative status and the blood lipid profile. Eighty Wistar rats (male and female) submitted to different intensities of a swimming regimen (low, LS; moderate, MS; or high, HS) for 16 weeks. Samples of blood and myocardium from the left ventricle were collected to determine lipid profiles and oxidative status. Reactive oxygen species (ROS) and antioxidant capacity against peroxyl radicals (ACAP), lipid profiles and lipid peroxidation was analyzed. ROS levels and ACAP were higher in male rats than in female rats overall (p<0.05). However, ACAP in the myocardium was significantly elevated in LS female rats compared to the MS and HS female rats, which had a significantly lower ACAP compared to all other groups. LS and MS training in both sexes and HS training (in females) led to significant decreases in the heart's lipid peroxidation. Amelioration of the lipid profile and reduction in oxidative damage contributed to a physiological state that benefits cardiovascular function in exercised animals. The results show that low and moderate intensity exercise promotes beneficial adaptations.

Effects of cryotherapy combined with therapeutic ultrasound on oxidative stress and tissue damage after musculoskeletal contusion in rats.

OBJECTIVE: To investigate the combined effects of cryotherapy and pulsed ultrasound therapy (PUT) on oxidative stress parameters, tissue damage markers and systemic inflammation after musculoskeletal injury. DESIGN: Experimental animal study. SETTING: Research laboratory. PARTICIPANTS: Seventy male Wistar rats were divided into five groups: control, lesion, cryotherapy, PUT, and cryotherapy+PUT. INTERVENTIONS: The gastrocnemius muscle was injured by mechanical crushing. Cryotherapy was applied immediately after injury (immersion in water at 10°C for 20minutes). PUT was commenced 24hours after injury (1MHz, 0.4W/cm2SPTA, 20% duty cycle, 5minutes). All animals were treated every 8hours for 3 days. MAIN OUTCOME MEASURES: Oxidative stress in muscle was evaluated by concentration of reactive oxygen species (ROS), lipid peroxidation (LPO), anti-oxidant capacity against peroxyl radicals (ACAP) and catalase. Plasma levels of creatine kinase (CK), lactate dehydrogenase (LDH) and C-reactive protein (CRP) were assessed. RESULTS: When applied individually, cryotherapy and PUT reduced CK, LDH, CRP and LPO caused by muscle damage. Cryotherapy+PUT in combination maintained the previous results, caused a reduction in ROS [P=0.005, mean difference -0.9×10-8 relative area, 95% confidence interval (CI) -0.2 to -1.9], and increased ACAP {P=0.007, mean difference 0.34 1/[relative area with/without 2,2-azobis(2-methylpropionamidine)dihydrochloride], 95% CI 0.07 to 0.61} and catalase (P=0.002, mean difference 0.41units/mg protein, 95% CI 0.09 to 0.73) compared with the lesion group. CONCLUSIONS: Cryotherapy+PUT in combination reduced oxidative stress in muscle, contributing to a reduction in adjacent damage and tissue repair.

Effects of different frequencies of transcutaneous electrical nerve stimulation on venous vascular reactivity.

Transcutaneous electrical nerve stimulation (TENS) is a type of therapy used primarily for analgesia, but also presents changes in the cardiovascular system responses; its effects are dependent upon application parameters. Alterations to the cardiovascular system suggest that TENS may modify venous vascular response. The objective of this study was to evaluate the effects of TENS at different frequencies (10 and 100 Hz) on venous vascular reactivity in healthy subjects. Twenty-nine healthy male volunteers were randomized into three groups: placebo (n=10), low-frequency TENS (10 Hz, n=9) and high-frequency TENS (100 Hz, n=10). TENS was applied for 30 min in the nervous plexus trajectory from the superior member (from cervical to dorsal region of the fist) at low (10 Hz/200 µs) and high frequency (100 Hz/200 µs) with its intensity adjusted below the motor threshold and intensified every 5 min, intending to avoid accommodation. Venous vascular reactivity in response to phenylephrine, acetylcholine (endothelium-dependent) and sodium nitroprusside (endothelium-independent) was assessed by the dorsal hand vein technique. The phenylephrine effective dose to achieve 70% vasoconstriction was reduced 53% (P<0.01) using low-frequency TENS (10 Hz), while in high-frequency stimulation (100 Hz), a 47% increased dose was needed (P<0.01). The endothelium-dependent (acetylcholine) and independent (sodium nitroprusside) responses were not modified by TENS, which modifies venous responsiveness, and increases the low-frequency sensitivity of α1-adrenergic receptors and shows high-frequency opposite effects. These changes represent an important vascular effect caused by TENS with implications for hemodynamics, inflammation and analgesia.

Effects of different frequencies of transcutaneous electrical nerve stimulation on venous vascular reactivity

Transcutaneous electrical nerve stimulation (TENS) is a type of therapy used primarily for analgesia, but also presents changes in the cardiovascular system responses; its effects are dependent upon application parameters. Alterations to the cardiovascular system suggest that TENS may modify venous vascular response. The objective of this study was to evaluate the effects of TENS at different frequencies (10 and 100 Hz) on venous vascular reactivity in healthy subjects. Twenty-nine healthy male volunteers were randomized into three groups: placebo (n=10), low-frequency TENS (10 Hz, n=9) and high-frequency TENS (100 Hz, n=10). TENS was applied for 30 min in the nervous plexus trajectory from the superior member (from cervical to dorsal region of the fist) at low (10 Hz/200 μs) and high frequency (100 Hz/200 μs) with its intensity adjusted below the motor threshold and intensified every 5 min, intending to avoid accommodation. Venous vascular reactivity in response to phenylephrine, acetylcholine (endothelium-dependent) and sodium nitroprusside (endothelium-independent) was assessed by the dorsal hand vein technique. The phenylephrine effective dose to achieve 70% vasoconstriction was reduced 53% (P<0.01) using low-frequency TENS (10 Hz), while in high-frequency stimulation (100 Hz), a 47% increased dose was needed (P<0.01). The endothelium-dependent (acetylcholine) and independent (sodium nitroprusside) responses were not modified by TENS, which modifies venous responsiveness, and increases the low-frequency sensitivity of α1-adrenergic receptors and shows high-frequency opposite effects. These changes represent an important vascular effect caused by TENS with implications for hemodynamics, inflammation and analgesia.

[Prevalence of virus B infection in a hospital community]. / Prevalência da infecção pelo vírus B na comunidade hospitalar.

The authors studied the prevalence of HBV markers among health care personnel of the University Hospital of the Federal University of Rio de Janeiro. The aim of study was to identify the high risk groups, in order to counsel vaccination of those groups, in order to counsel vaccination of those groups at risk as a routine. As a control group, a group of office workers of the hospital were chosen. A significant difference of incidence of HBV markers, mainly in surgeons (40%) and hemodialysis unit personnel (36.4%) when compared to the control group, was observed (p less than 0.05). The incidence increased with age and the time spent in the profession. The authors concluded that vaccination is indicated in surgeons hemodialysis personnel, dentists and laboratory personnel.