Vascular redox imbalance in rats submitted to chronic exercise

Exercise training has been used for treatment/prevention of many cardiovascular diseases, but the mechanisms need to be clarified. Thus, our aim was to compare oxidative stress parameters between rats submitted to a swimming training and sedentary rats (control). Twelve male rats were divided into two groups: control and exercise training. The exercise training had daily 1 h swimming sessions for 8 weeks and a load (5% of its body mass) was placed in rat's tail. Thereafter the animals were killed, aorta and heart were surgically removed and blood was collected. Body mass gain, thiobarbituric acid reactive species (TBARS), carbonyl content, total reactive antioxidant potential (TRAP), total antioxidant reactivity (TAR), superoxide dismutase (SOD) activity and catalase (CAT) activity were evaluted. The trained rats showed a lower body mass gain and no modifications on heart. An increased SOD activity was observed on aorta after the training, but no changes were seen for CAT activity, which led to an increased SOD/CAT ratio. The arterial TBARS was also increased for trained rats. The decrease in TRAP in exercise training was the single modification on plasma. Our findings suggest that the increased SOD activity could play a role in vascular adaptations to exercise training. Copyright © 2010 John Wiley & Sons, Ltd.     

Effect of endurance training on the phospholipid content of skeletal muscles in the rat

Only few data are available on the effect of training on phospholipid metabolism in skeletal muscles. The aim of the present study was to examine the effect of 6 weeks of endurance training on the content of particular phospholipid fractions and on the incorporation of blood-borne [14C]-palmitic acid into the phospholipids in different skeletal muscles (white and red sections of the gastrocnemius, the soleus and the diaphragm) of the rat. Lipids were extracted from the muscles and separated using thin-layer chromatography into the following fractions: sphingomyelin, phosphatidylcholine, phosphatidylserine, phosphatidylinositol, phosphatidylethanolamine, cardiolipin and neutral lipids (this fraction being composed mostly of triacylglycerols). It was found that training did not affect the content of any phospholipid fraction in soleus muscle. It increased the content of sphingomyelin in white gastrocnemius muscle, cardiolipin and phosphatidylethanolamine in red gastrocnemius muscle and phosphatidylinositol in white gastrocnemius muscle and diaphragm. The total phospholipid content in red gastrocnemius muscle of the trained group was higher than in the control group. Training reduced the specific activity of sphingomyelin and cardiolipin in all muscles, phosphatidylcholine in soleus, red, and white gastrocnemius muscles, phosphatidylserine in all muscles, phosphatidylinositol in all except the soleus muscle, and phosphatidylethanolamine in hindleg muscles, but not in the diaphragm compared to the corresponding values in the sedentary group. It was concluded that endurance training affects skeletal muscle phospholipid content and the rate of incorporation of the blood-borne [14C]palmitic acid into the phospholipid moieties.     

Quantitative data on training new world primates to urinate

This study assessed the effectiveness of operant conditioning in training three species of captive callitrichid primates (Leontopithecus rosalia, Callithrix geoffroyi, and Saguinus imperator) to urinate on demand. There were three goals to the study: 1) to develop a system for quantitatively assessing positive reinforcement training; 2) to ascertain whether or not positive reinforcement techniques can be used to train callitrichid monkeys to urinate on demand, and if so, how many training sessions are required; and 3) to determine the effect on urination behavior of the trainer entering the cage to collect a urine sample. Positive reinforcement with a continuous reinforcement schedule was used to capture a natural behavior: urination. Training sessions (30 min each) were conducted at dawn thrice weekly during five consecutive phases: habituation, control, training (animals were rewarded for urinating), maintenance (animals had reached a defined training criteria and continued to be rewarded for urinating), and collection (animals were rewarded for urinating, and the trainer entered the cage to collect the sample). The numbers of 30-min training sessions required to train the three monkey species (L. rosalia, C. geoffroyi, and S. imperator) were five, six, and eight, respectively. For the three species, the mean number of urinations per animal was significantly greater during the training, maintenance, and collection phases compared to the control phase. However, the three species differed significantly in the manner in which the rates of urination changed across the five phases. A higher proportion of subjects urinated during the training, maintenance, and collection phases compared to the control phase. Latency to first urination varied significantly across the five phases, with significantly reduced latencies to urinate during the training, maintenance, and collection phases compared to the control phase. The entry of the trainer into the cage to collect the urine sample did not appear to alter urination behavior. We demonstrate that operant conditioning techniques, which typically incur minimal cost, time investment, and disturbance, can be used to increase the quantity of urine samples collected for physiological analysis, the proportion of animals that urinate, and the speed of sample collection.     

The influence of training on chemosensory event-related potentials and interactions between the olfactory and trigeminal systems

It is not possible to accurately predict the perceptual response to odorants and odorant mixtures without understanding patterns of suppression and facilitation that result from interactions between the olfactory and trigeminal systems. The current study extends previous findings by exploring the effect of intensive training on the interaction between these systems and also by using a different mixed chemosensory stimulus to examine whether the principles established in earlier studies generalize to different odorants. Stimuli were chosen so as to selectively activate the olfactory (H2S) and trigeminal (CO2) nerves. In addition, linalool was included as a stimulus that activated both systems. Thirty-five participants (19 men, 16 women) rated the intensity of each stimulus when presented both alone and in binary mixtures (linalool + H2S, and linalool + CO2). Chemosensory event-related potentials were obtained from three recording positions. Analysis of intensity ratings showed that linalool was significantly less intense than the other stimuli when presented alone. In binary mixtures, H2S was strongly suppressed by linalool. One week of intensive odor training produced significant and specific reductions in the intensity of linalool and H2S, both alone and in their mixture. Training with a different odor (champignol) had no effect. Chemosensory event-related potential data confirmed previous findings showing changes in topographical distribution that reflected the degree of trigeminal activity. Binary mixtures generally produced larger amplitudes than single stimuli. Latencies clearly differentiated between the three single stimuli and the binary mixtures. Changes were observed in event-related potentials that reflected those obtained for intensity ratings in that they were observed for linalool and H2S in the linalool trained group only. The amplitude of the late 'endogenous' component (P3) was significantly decreased for these odors at frontal recording sites. In summary, strong and specific training effects were observed in intensity ratings for participants trained with the test odor (linalool), but not for those trained with a different odor. This was supported by a significant decrease of amplitudes of the event-related potentials at frontal recording sites following training with the test odor only     

Group Training with Healthy Computing Practices to Prevent Repetitive Strain Injury (RSI): A Preliminary Study

This pilot study investigated whether group training, in which participants become role models and coaches, would reduce discomfort as compared to a nontreatment Control Group. Sixteen experimental participants participated in 6 weekly 2-hr group sessions of a Healthy Computing program whereas 12 control participants received no training. None of the participants reported symptoms to their supervisors nor were they receiving medical treatment for repetitive strain injury prior to the program. The program included training in ergonomic principles, psychophysiological awareness and control, sEMG practice at the workstation, and coaching coworkers. Using two-tailed t tests to analyze the data, the Experimental Group reported (1) a significant overall reduction in most body symptoms as compared to the Control Group and (2) a significant increase in positive work-style habits, such as taking breaks at the computer, as compared to the Control Group. This study suggests that employees could possibly improve health and work style patterns based on a holistic training program delivered in a group format followed by individual practice.     

Remotely Sensed Interannual Variations and Trends in Terrestrial Net Primary Productivity 1981–2000

Spatial and temporal variations in net primary production (NPP) are of great importance to ecological studies, natural resource management, and terrestrial carbon sink estimates. However, most of the existing estimates of interannual variation in NPP at regional and global scales were made at coarse resolutions with climate-driven process models. In this study, we quantified global NPP variation at an 8 km and 10-day resolution from 1981 to 2000 based on satellite observations. The high resolution was achieved using the GLObal Production Efficiency Model (GLO-PEM), which was driven with variables derived almost entirely from satellite remote sensing. The results show that there was an increasing trend toward enhanced terrestrial NPP that was superimposed on high seasonal and interannual variations associated with climate variability and that the increase was occurring in both northern and tropical latitudes. NPP generally decreased in El Niño season and increased in La Niña seasons, but the magnitude and spatial pattern of the response varied widely between individual events. Our estimates also indicate that the increases in NPP during the period were caused mainly by increases in atmospheric carbon dioxide and precipitation. The enhancement of NPP by warming was limited to northern high latitudes (above 50°N); in other regions, the interannual variations in NPP were correlated negatively with temperature and positively with precipitation.     

AGE-breakers cleave model compounds,but do not break Maillard crosslinks in skin and tail collagen from diabetic rats

Advanced glycation end products (AGE), formed by nonenzymatic Maillard reactions between carbohydrate and protein, contribute to the increase in chemical modification and crosslinking of tissue proteins with age. Acceleration of AGE formation in collagen during hyperglycemia, with resultant effects on vascular elasticity and basement membrane permeability, is implicated in the pathogenesis of diabetic complications. AGE-breakers, such as N-phenacylthiazolium (PTB) and N-phenacyl-4,5-dimethylthiazolium (PMT) halides, have been proposed as therapeutic agents for reversing the increase in protein crosslinking in aging and diabetes. We have confirmed that these compounds, as well as the AGE-inhibitor pyridoxamine (PM), cleave the model AGE crosslink, phenylpropanedione, and have studied the effects of these compounds in reversing the increased crosslinking of skin and tail collagen isolated from diabetic rats. Crosslinking of skin collagen, measured as the half-time for solubilization of collagen by pepsin in 0.5M acetic acid, was increased approximately 5-fold in diabetic, compared to nondiabetic rats. Crosslinking of tail tendon collagen, measured as insolubility in 0.05 N acetic acid, was increased approximately 10-fold. Collagen preparations were incubated in the presence or absence of AGE-breakers or PM in phosphate buffer, pH 7.4, for 24h at 37 degrees C. These treatments did not decrease the half-time for solubilization of diabetic skin collagen by pepsin or increase the acid solubility of diabetic tail tendon collagen. We conclude that, although AGE-breakers and PM cleave model crosslinks, they do not significantly cleave AGE crosslinks formed in vivo in skin collagen of diabetic rats.     

Enhancing Proper Sitting Position Using a New sEMG Protocol, The “Minimax” Procedure, With Boolean Logic

The modification of posture in children using sEMG is a new area that offers much potential to aid disabled children regain function. This article describes a new protocol, the minimax procedure, to aid children regain motor function in sitting. The protocol uses selective reinforcement to encourage recruiting/relaxing target sites (gluteus medius/maximus) in a predetermined way so as to encourage good form in sitting. Children often are unaware how to make changes in posture, and when they do succeed the progress is so slow that sustaining motivation is a challenge. This paper describes a procedure that helps the child recognize when they have achieved the correct posture, immediately rewards them for doing so, and generates data using Boolean operations to numerically substantiate the clinically observed changes in posture.     

The modification of cortical reorganization and chronic pain by sensory feedback

Recent neuroscientific evidence has revealed that the adult brain is capable of substantial plastic change in areas such as the primary somatosensory cortex that were formerly thought to be modifiable only during early experience. We discuss research on phantom limb pain as well as chronic back pain that revealed functional reorganization in both the somatosensory and the motor system in these chronic pain states. In phantom limb pain patients, cortical reorganization is correlated with the amount of phantom limb pain; in low back pain patients the amount of reorganizational change increases with chronicity. We present a model of the development of chronic pain that assumes an important role of somatosensory pain memories. In phantom limb pain, we propose that those patients who experienced intense pain prior to the amputation will later likely develop enhanced cortical reorganization and phantom limb pain. We show that cortical plasticity related to chronic pain can be reduced by behavioral interventions that provide feedback to the brain areas that were altered by somatosensory pain memories.