Differential expression of the regulator of G protein signaling RGS9 protein in nociceptive pathways of different age rats

Regulators of G protein signaling (RGS) proteins are GTPase-activating proteins which act as modulators of G-protein-coupled receptors. RGS9 has two alternative splicing variants. RGS9-1 is expressed in the retina. RGS9-2 is expressed in the brain, especially abundant in the striatum. It is believed to be an essential regulatory component of dopamine and opioid signaling. In this study, we compared the expression of RGS9 proteins in the nervous system of different age groups of rats employing immunocytochemistry. In both 3-week- and 1-year-old rats, RGS9 is expressed abundantly in caudate-putamen, nucleus accumbens, and olfactory tubercle. It is also expressed abundantly in the ventral horn of the spinal cord and the dorsal root ganglion (DRG) cells. Quantitative analysis showed that the intensities of RGS9 expression in 1-year-old rats are higher than those in the 3-week-old rats in caudate-putamen, nucleus accumbens, olfactory tubercle, periaqueductal gray, and gray matter of the spinal cord. In contrast, in thalamic nuclei and locus coeruleus, the intensities of RGS9 immunostaining in 3-week-old rats are higher than in 1-year-old rats. In DRG cells, there is no significant difference between the two age groups. These data suggest that RGS9 is differentially expressed with age. Such differential expression may play an important role in neuronal differentiation and development as well as in neuronal function, such as dopamine and opioid signaling.     

Antioxidant restriction and oxidative stress in short-duration exhaustive exercise

PURPOSE: To determine the effect of dietary antioxidant restriction on oxidative stress, antioxidant defenses, and exercise performance in athletes. Oxidative stress has been shown to increase during exercise. To alleviate oxidative stress, a high intake of antioxidant rich foods or supplements may be required in trained athletes. METHODS: Plasma oxidative stress and antioxidant defenses were examined in 17 trained athletes who underwent two separate exercise tests. Before the initial exercise test participants followed their habitual (high) antioxidant (H-AO) diets. Then they followed a 2-wk restricted-antioxidant (R-AO) diet before the second exercise test. Blood was taken at rest, after submaximal and high-intensity exhaustive exercise, and after 1 h of recovery. RESULTS: The R-AO diet induced a threefold reduction in antioxidant intake when compared with habitual-antioxidant (H-AO) diets. F(2)-isoprostane concentration (marker of oxidative stress) was significantly higher after submaximal exercise (38%), exhaustion (45%), and 1 h of recovery (31%) when following the R-AO diet compared with the H-AO diet. Rate of perceived exertion was increased on the R-AO diet whilst exercise time to exhaustion was not affected. Total antioxidant capacity and circulating antioxidant concentrations, although not significantly different, tended to be lower when following the R-AO diet. CONCLUSION: Athletes regularly participating in up to 40 min of acute high-intensity exercise may require higher intakes of exogenous antioxidants to defend against increased oxidative stress during exercise, which can be met through an adequate intake of high-antioxidant foods. Thus, there seems no valid reason to recommend antioxidant supplements to athletes participating in acute high-intensity exercise events up to 40 min in duration, except in those known to be consuming a low-antioxidant diet for prolonged periods.     

Optimum tension for partial ossicular replacement prosthesis reconstruction in the human middle ear

OBJECTIVE: Hearing results from ossiculoplasty are unpredictable. There are many potentially modifiable parameters. One parameter that has not been adequately investigated in the past is the effect of tension on the mechanical functioning of the prosthesis. Our goal was to investigate this parameter further, with the hypothesis that the mechanical functioning of partial ossicular replacement prostheses (PORP) from the stapes head to the eardrum will be affected by the tension that they are placed under. METHODS: Fresh temporal bones were used to reconstruct a missing incus defect with a PORP-type prosthesis. Three different lengths of PORP were used, and the stapes vibrations were measured with a laser Doppler vibrometer using a calibrated standard sound in the ear canal. Eight temporal bones were used. RESULTS: Tension had a very significant effect on stapes vibration. In general, loose prostheses resulted in the best overall vibration transmission. The effects were most marked at the lower frequencies. There was a slight advantage to tight prostheses in the higher frequencies, but much less than the decrement in lower frequencies with tight prostheses. CONCLUSION: In ossicular reconstruction, best stapes vibration results in our model are achieved by shorter prostheses, which result in lower tension.     

Increased intracranial volume: a clue to the etiology of idiopathic normal-pressure hydrocephalus?

BACKGROUND AND PURPOSE: The etiology of idiopathic normal-pressure hydrocephalus (NPH) is unknown. The purpose of this study was to examine the hypothesis that NPH begins in infancy as benign external hydrocephalus due to decreased uptake of CSF by the arachnoid villi. Since this occurs before the sutures fuse, a secondary hypothesis is that the intracranial volumes of patients with NPH should be larger than those of healthy individuals. METHODS: Intracranial volumes of 51 patients with clinically suspected NPH were compared with those of age- and sex-matched control subjects. All patients underwent phase-contrast CSF velocity MR imaging. They had aqueductal CSF stroke volumes of at least 60 microL, which was 50% higher than previously published normal values. Intracranial volumes were measured and compared between groups. RESULTS: The average intracranial volume for men with NPH (n = 22) was 1682 mL compared with 1565 for male control subjects (n = 55). The NPH volume averaged 118 mL (7.5%) larger than the control volume (P = .003). The average intracranial volume for women with NPH (n = 29) was 1493 mL compared with 1405 mL for female control subjects (n = 55). The NPH volume was 88 mL (6.3%) larger than the control volume (P = .002). CONCLUSION: Patients with NPH have intracranial volumes significantly larger than normal, suggesting that the initial insult occurs before the sutures fuse at 1 year of age. The patients somehow remain asymptomatic until their later years, when a second insult must occur, leading to symptomatic NPH.     

Brief interventions for alcohol related problems

This article presents the concepts and basic premises that are necessary for a better understanding of the Brief Interventions (BIs), with a literature review of its effectiveness and a discussion about BIs in Brazil. The theoretical premises are discussed, as well the concepts represented by the acronym FRAMES: Feedback; Responsibility; Advice; Menu; Empathic and Self-efficacy. Results of systematic reviews and metanalysis about BIs effectiveness are discussed and a summary box with the main studies is presented. Finally, the recent developments about the introduction of BIs in Brazil are commented. The importance of health professionals training and the adoption of BIs within different settings are emphasized considering its demonstrated effectiveness and economic feasibility.