Occlusal Loading Effect on Stress Distribution of Endodontically Treated Teeth: Finite Element Analysis Study.

AIM: Evaluate the influence of occlusal loading on the stress distribution of endodontically treated teeth after root canal preparation with different file's sizes and tapers by means of finite element analysis. METHODOLOGY: Seven three-dimensional models of a single-rooted, single-canal lower second premolar were established, one healthy control and six endodontically treated and restored models. The shape of root canal preparations followed file configurations 30/.05, 30/.09, 35/.04, 35/.06, 40/.04, and 40/.06. Von- Mises equivalent stresses were calculated by applying 30 N, 90 N and 270 N loads to the buccal cusp tip, each one at 90º, 45º and 20º angles from the occlusal plane simulating occlusion, dental interference and laterality, respectively. RESULTS: 45º loading was more prone to formation of higher stress values. The simulation of occlusion and laterality resulted in maximum stress areas located at the inner side of the root curvature, while under occlusal interference they were on the lingual surface over the tooth's long axis. CONCLUSIONS: The angulation of occlusal loading and magnitude were determinants for stress distribution on dental structure. Both variations of size and taper were not determinants for the increase in the maximum stress areas.

Vitamin E supplementation inhibits muscle damage and inflammation after moderate exercise in hypoxia.

BACKGROUND: Exercise under hypoxic conditions represents an additional stress in relation to exercise in normoxia. Hypoxia induces oxidative stress and inflammation as mediated through tumour necrosis factor (TNF)-α release that might be exacerbated through exercise. In addition, vitamin E supplementation might attenuate oxidative stress and inflammation resulting from hypoxia during exercise. The present study aimed to evaluate the effects of vitamin E supplementation (250 mg) on inflammatory parameters and cellular damage after exercise under hypoxia simulating an altitude of 4200 m. METHODS: Nine volunteers performed three sessions of 60 min of exercise (70% maximal oxygen uptake) interspersed for 1 week under normoxia, hypoxia and hypoxia after vitamin E supplementation 1 h before exercise. Blood was collected before, immediately after and at 1 h after exercise to measure inflammatory parameters and cell damage. RESULTS: Percentage oxygen saturation of haemoglobin decreased after exercise and recovered 1 h later in the hypoxia + vitamin condition (P < 0.05). Supplementation decreased creatine kinase (CK)-TOTAL, CK-MB and lactate dehydrogenase 1 h after exercise (P < 0.05). The exercise in hypoxia increased interleukin (IL)-6, TNF-α, IL-1ra and IL-10 immediately after exercise (P < 0.05). Supplementation reversed the changes observed after exercise in hypoxia without supplementation (P < 0.05). CONCLUSIONS: We conclude that 250 mg of vitamin E supplementation at 1 h before exercise reduces cell damage markers after exercise in hypoxia and changes the concentration of cytokines, suggesting a possible protective effect against inflammation induced by hypoxia during exercise.

Cytogenetic evaluation of tannery workers in the city of Teresina, northeastern Brazil.

Assessments of chromosomal integrity and structure enable the prevention of diseases associated with the work environment, with the frequencies of chromosomal aberrations and micronuclei often being used as markers in biomonitoring. Owing to their routine manipulation of potentially toxic chemicals, tannery workers as a group merit a more thorough evaluation and discussion. This study investigated chromosomal damage in 30 workers from a tannery in the city of Teresina, the state capital of Piauí, northeast Brazil, and a control group consisting of 30 employees from a nearby accounting firm. The frequencies of chromosomal aberrations (CAs) and binucleated cell micronuclei (MN) were assessed as a measure of damage. Means were compared using the Student t-test and ANOVA-Dunnett test. Our results indicated a higher number of CAs in exposed individuals compared to the control group, including dicentric (P < 0.0001) and tricentric chromosomes (P < 0.001), and those in ring (P < 0.0001) and acentric ring forms (P < 0.001). Assessment of MN frequency demonstrated a similar trend (exposed vs control, P < 0.0001). It was concluded that the tannery workers in this study exhibited a higher incidence of genetic damage than comparable unexposed individuals. However, further research on this subject is needed, particularly in regard to potentially clastogenic agents used in the tanning process.

Moderate exercise training modulates cytokine profile and sleep in elderly people.

Aging causes several physiological alterations, including alterations in sleep. It is possible that difficulty sleeping can be exacerbated by increased inflammation in older individuals. Moderate exercise training may be a modality of non-pharmacological treatment for sleep disorders and inflammation. We aimed to assess the effects of moderate exercise training on sleep in elderly people as well as their cytokine profiles. Additionally, we examined the effect of exercise training on quality of life parameters using a SF-36 questionnaire. Twenty-two male, sedentary, healthy, elderly volunteers performed moderate training for 60 min/day, 3 days/week for 24 week at a work rate equivalent to their ventilatory aerobic threshold. The environment was kept at a temperature of 23 ± 2°C, with a humidity of 60 ± 5%. Blood and polysomnograph were collected twice: at baseline (1 week before training began) and after 6 months of training. Training increased aerobic capacity parameters (p<0.0001), decreased REM latency (p<0.02), and decreased time awake (p<0.05). After training, the levels of IL-6 (p<0.0001) and TNF-α (p<0.0001) and the ratio of TNF-α/IL-10 (p<0.0001) were decreased, whereas IL-10 levels were increased after training (p<0.001). Furthermore, exercise training was shown to improve quality of life parameters. Our results suggest that 6 months of training can improve sleep in the elderly and is related to the anti-inflammatory effect of moderate training, which modifies cytokine profiles.

Chronic exercise promotes alterations in the neuroendocrine profile of elderly people.

Aging and physical inactivity are 2 factors that favour the development of cardiovascular disease, metabolic syndrome, obesity, and diabetes. In contrast, adopting a habitual moderate exercise routine may be a nonpharmacological treatment alternative for neuroendocrine aging disorders. We aimed to assess the effects of moderate exercise training on the metabolic profiles of elderly people with sedentary lifestyles. Fourteen sedentary, healthy, elderly male volunteers participated in a moderate training regimen for 60 min/day, 3 days/week for 24 weeks at a work rate equivalent to their ventilatory aerobic threshold. The environment was maintained at a temperature of 23±2°C, with a humidity of 60±5%. Blood samples for analysis were collected at 3 intervals: at baseline (1 week before training began), and 3 and 6 months after training. The training promoted increased aerobic capacity (relative VO(2), and time and velocity to VO(2)max; (p<0.05)) and reduced serum α-MSH (p<0.05) after 3 months of training when compared with the baseline data. In addition, serum thyroid hormone (T3 and T4) was reduced after 6 months of training compared with baseline levels. Our results demonstrate that a moderate exercise training protocol improves the metabolic profile of older people, and metabolic adaptation is dependent on time.

The Possible Importance of Glutamine Supplementation to Mood and Cognition in Hypoxia from High Altitude.

Hypoxia induced by low O2 pressure is responsible for several physiological and behavioral alterations. Changes in physiological systems are frequent, including inflammation and psychobiological declines such as mood and cognition worsening, resulting in increased reaction time, difficulty solving problems, reduced memory and concentration. The paper discusses the possible relationship between glutamine supplementation and worsening cognition mediated by inflammation induced by high altitude hypoxia. The paper is a narrative literature review conducted to verify the effects of glutamine supplementation on psychobiological aspects. We searched MEDLINE/PubMed and Web of Science databases and gray literature by Google Scholar for English articles. Mechanistic pathways mediated by glutamine suggest potential positive effects of its supplementation on mood and cognition, mainly its potential effect on inflammation. However, clinical studies are scarce, making any conclusions impossible. Although glutamine plays an important role and seems to mitigate inflammation, clinical studies should test this hypothesis, which will contribute to a better mood and cognition state for several people who suffer from problems mediated by hypoxia.

Carbohydrate supplementation and psychophysiological responses during moderate exercise in hypoxia.

BACKGROUND: Rating of Perceived Exertion (RPE) is a subjective scale to monitor overload and fatigue during exercise. Hypoxia may worsen the perception of fatigue, compromising the self-reported perception of effort and increasing RPE. The objective was to evaluate the effects of carbohydrate (CHO) supplementation on RPE during exercise in hypoxia simulating 4200 m. METHODS: Eight male physically active volunteers performed two exercises at 50% VO2peak and 1% slope: exercise in hypoxia + placebo or exercise in hypoxia + CHO (6% maltodextrin) with supplementation at 20, 40, and 60 min during exercise. Oxygen Saturation (SaO2%) was assessed at baseline and after exercise, while RPE and HR were measured each 10 min during the trial. RESULTS: SaO2% decreased after exercise in both conditions of hypoxia compared to rest. The RPE did not differ between groups. However, the RPE increased in hypoxia after 20 min of exercise in relation to 10 min. The Area Under the Curve (AUC) of RPE was lower in hypoxia + CHO compared to hypoxia. The AUC of the HR/RPE ratio in the hypoxia + CHO group was higher in relation to hypoxia. CONCLUSIONS: Our results indicate that CHO supplementation does not change RPE induced by 60 min of exercise at 50% VO2peak in hypoxia equivalent to 4200 m at the different times analyzed. However, in hypoxia + CHO the (AUC)-60 min of total RPE decreased during exercise, while the heart rate/RPE ratio improved, indicating lower RPE in the hypoxic environment.

Effect of endurance training on hypothalamic serotonin concentration and performance.

1. Serotonin is a neurotransmitter that modulates several functions, such as food intake, energy expenditure, motor activity, mood and sleep. Acute exhaustive endurance exercise increases the synthesis, concentration and metabolism of serotonin in the brain. This phenomenon could be responsible for central fatigue after prolonged and exhaustive exercise. However, the effect of chronic exhaustive training on serotonin is not known. The present study was conducted to examine the effect of exhaustive endurance training on performance and serotonin concentrations in the hypothalamus of trained rats. 2. Rats were divided into three groups: sedentary rats (SED), moderately trained rats (MOD) and exhaustively trained rats (EXT), with an increase of 200% in the load carried during the final week of training. 3. Hypothalamic serotonin concentrations were similar between the SED and MOD groups, but were higher in the EXT group (P < 0.05). Performance was lower in the EXT group compared with the MOD group (P < 0.05). 4. Thus, the present study demonstrates that exhaustive training increases serotonin concentrations in the hypothalamus, together with decreased endurance performance after inadequate recovery time. However, the mechanism underlying these changes remains unknown.

Beyond flat weals: validation of a three-dimensional imaging technology that will improve skin allergy research.

Skin-prick tests (SPTs) are a standard way to test for sensitizations to allergens, but to date, techniques that allow for high-quality measurements of the resulting weals for research purposes are lacking. In this study, we assessed a new three-dimensional (3D) imaging technology for its accuracy and consistency. We found that this new technology showed very little intraoperator and interoperator variation for repeated measurements of a model of known area by each of two operators. We also found that repeated measurements of the same object over 4 months showed virtually no variation. Finally, 3D imaging was superior to traditional ruler measurements for assessing SPT reactions to histamine and allergen. For high-quality measurements of SPT reactions, 3D imaging is accurate, consistent and reliable.

Exercise, sleep and cytokines: is there a relation?

Physical exercise is a modality of non-pharmacological treatment for sleep disorders. Contradicting results are still found in studies of the effect of exercise on sleep. Among the substances that have been described as sleep modulators, cytokines produced during the recovery period after an acute exercise session are very important. Various studies have verified that physical exercise may alter the plasma concentration of the many pro-inflammatory cytokines that may in turn modulate sleep. A number of factors seem to mediate this effect of exercise, including duration, intensity, and form of exercise, in addition to temperature and metabolic alterations. The mechanisms through which exercise promotes alterations in sleep architecture remain to be clarified. Researchers speculate that many hormones and substances produced by metabolism may affect sleep. Therefore, the object of this review is to discuss the effects of exercise and cytokines on sleep, and the relation between these two sleep-regulating components, raising the hypothesis that the alterations in sleep promoted by exercise are mediated by cytokines, which, by increasing the nREM sleep phase, would stimulate the regenerating characteristics of sleep.

Endurance training restores peritoneal macrophage function in post-MI congestive heart failure rats.

Congestive heart failure (CHF) induces a state of immune activation, and peritoneal macrophages (M phi s) may play an important role in the development and progression of one such condition. Moderate endurance training modulates peritoneal M phi function. We evaluated the effect of endurance training on different stages of the phagocytic process and in the production of interleukin-6 (IL-6), interleukin-1beta (IL-1beta) and tumor necrosis factor-alpha (TNF-alpha) after LPS stimulation. Either ligation of the left coronary artery or Sham operations were performed in adult Wistar rats. After 4 wk, control (Sham operated) and MI (ligation of the left coronary artery) animals were randomly assigned to either a sedentary (Sham-operated sedentary, n = 7 and MI sedentary, n = 10) or a trained group (Sham-operated trained, n = 8 and MI trained, n = 8). Trained rats ran on a treadmill (0% grade at 13-20 m/min) for 60 min/day, 5 days/wk, for 8-10 wk, whereas sedentary rats had only limited activity. Training increased maximal oxygen uptake normalized for body weight (ml.kg(-1).min(-1)), as well as skeletal muscle citrate synthase maximal activity, when compared with sedentary groups. The resident and total cell number, the chemotaxis index, and the production of TNF-alpha stimulated by LPS were significantly higher in the MI sedentary group when compared with the Sham sedentary group. Moderate endurance training reversed these alterations promoted by post-MI. These results demonstrate that moderate intensity exercise training modulates peritoneal M phi function and induces beneficial metabolic effects in rats with post-MI CHF.

Sleep quality and duration are associated with performance in maximal incremental test.

BACKGROUND AND OBJECTIVE: Inadequate sleep patterns may be considered a trigger to development of several metabolic diseases. Additionally, sleep deprivation and poor sleep quality can negatively impact performance in exercise training. However, the impact of sleep duration and sleep quality on performance during incremental maximal test performed by healthy men is unclear. Therefore, the purpose of the study was to analyze the association between sleep pattern (duration and quality) and performance during maximal incremental test in healthy male individuals. METHODS: A total of 28 healthy males volunteered to take part in the study. Sleep quality, sleep duration and physical activity were subjectively assessed by questionnaires. Sleep pattern was classified by sleep duration (>7h or <7h of sleep per night) and sleep quality according to the sum of measured points and/or scores by the Pittsburgh Sleep Quality Index (PSQI). Incremental exercise test was performed at 35 watts for untrained subjects, 70 watts for physically active subjects and 105 watts for well-trained subjects. RESULTS: HRmax was correlated with sleep quality (r=0.411, p=0.030) and sleep duration (r=-0.430, p=0.022). Participants reporting good sleep quality presented higher values of Wmax, VO2max and lower values of HRmax when compared to participants with altered sleep. Regarding sleep duration, only Wmax was influenced by the amount of sleeping hours per night and this association remained significant even after adjustment by VO2max. CONCLUSION: Sleep duration and quality are associated, at least in part, with performance during maximal incremental test among healthy men, with losses in Wmax and HRmax. In addition, our results suggest that the relationship between sleep patterns and performance, mainly in Wmax, is independent of fitness condition.

Risk of tuberculous infection in an indigenous population from Amazonia, Brazil.

SETTING: Suruí Indians, Amazonia, Brazil. OBJECTIVE: To estimate the prevalence and the annual risk of infection (ARI) of tuberculosis (TB) in an indigenous population in Brazil. METHODS: We applied a method to estimate the prevalence of TB infection in populations with high bacille Calmette-Guérin (BCG) vaccine coverage. The method consisted of comparing levels of skin test reactivity in individuals tested with purified protein derivative (PPD) before and after stimulation with intradermal BCG. Fieldwork was carried out among the Suruí Indians (n = 993) in two phases, 3 months apart. RESULTS: A total of 645 subjects were tested. In pre-BCG revaccination, tuberculin skin test (TST) indurations averaged 5.9 mm (33.5% > or =10 mm). In post-BCG revaccination TST, indurations averaged 9.4 mm (48.7% > or =10 mm). Conversion from non-reactor to reactor was 54.4%. The ARI ranged from 1.2% to 2.2%. In the logistic regression, age and history of TB were the strongest independent predictors of TB infection. BCG scar and the number of individuals per house were also associated with infection. CONCLUSION: Tuberculous transmission is very high in the Suruí, surpassing the ARI reported for Brazil (0.6%). The epidemiology of TB in this indigenous population is related to unfavourable social and economic conditions, as well as to deficient health care services.

Effects of a 30-km race upon salivary lactate correlation with blood lactate.

Blood lactate has been used to determine the aerobic capacity and long distance performance. Recently, a new methodology has been suggested to supplant the invasive blood lactate techniques. Salivary lactate has received attention because it shows high correlation to blood lactate in progressive overload test. We evaluated the correlation between salivary and blood lactate during a long distance run and assessed possible changes in salivary lactate concentration. Fifteen expert marathon racers ran 30 km as fast as possible. Saliva and 25 muL of blood were collected at rest and at each 6 km for lactate determination. Blood lactate concentration increased in the 6th km and then remained constant until the end of the race. Salivary lactate increased after 18 km in relation to basal. We found high correlations between blood and saliva absolute lactate (r=0.772, p<0.05) and the blood lactate relative concentration corrected by protein (r=0.718, p<0.05). The highest correlation found between absolute and relative salivary lactate was r=0.994 (p<0.001). Our results show that it is possible to use salivary lactate with absolute values or relative protein concentration. In addition, salivary lactate showed a high correlation with blood lactate in endurance events.

Pre-task music improves swimming performance.

AIM: The purpose of this study was to investigate the effects of pre-task music on swimming performance and other psychological variables. METHODS: A randomized counterbalanced within-subjects (experimental and control condition) design was employed. Eighteen regional level male swimmers performed two 200-m freestyle swimming time trials. Participants were exposed to either 5 minutes of self-selected music (pre-task music condition) or 5 minutes of silence (control condition) and, after 1 minute, performed the swimming task. RESULTS: Swimming time was significantly shorter (-1.44%) in the pre-task music condition. Listening to pre-task music increased motivation to perform the swimming task, while arousal remained unchanged. While fatigue increased after the swimming task in both conditions, vigor, ratings of perceived exertion and affective valence were unaltered. CONCLUSION: It is concluded, for the first time, that pre-task music improves swimming performance.

Tuberculin reactivity and tuberculosis epidemiology in the Pakaanóva (Wari') Indians of Rondônia, south-western Brazilian Amazon.

OBJECTIVE: To investigate the characteristics of tuberculin skin test reactivity in the Pakaanóva Indians, in Amazonia, Brazil, after revaccination of all study participants with bacille Calmette-Guerin (BCG). METHODS: The investigation was designed as a post-BCG vaccination purified protein derivative (PPD) survey. Data included PPD readings, age, sex, nutritional status, place of residence, previous tuberculosis, physical examinations and BCG status. Bivariate and multivariate logistic regression analyses were conducted. RESULTS: About 90% (n = 505) of the total population participated. One third (32.1%) of the subjects presented induration > or = 10 mm at 72 h. Induration sizes showed weak linear correlation with age; differences between sexes were not observed. Skin reaction was not associated with nutritional status. Individuals with a history of tuberculosis were six times more likely to test positive. History of tuberculosis, age, and previous BCG vaccination were significantly associated with PPD reactivity in the multivariate analyses. CONCLUSION: The Pakaanóva showed a high proportion (58.4%) of non-reactors, even with a recent BCG booster. Sex differences in PPD reactivity were either not present or could not be demonstrated. The association between age and PPD reactivity resembles that observed in other Amazonian populations. The authors discuss the potential of PPD testing as a screening tool to enhance tuberculosis detection, especially in indigenous populations in Amazonia with limited access to health services.

Cutaneous leishmaniasis in Tupí-Mondé Amerindians from the Brazilian Amazonia.

This paper reports the results of a cross-sectional survey aimed at characterizing the epidemiology of American cutaneous leihsmaniasis (ACL) in 3 Tupí-Mondé-speaking Amerindian groups from the Brazilian Amazon region. Data include results of Montenegro skin tests (n = 550), serology (n = 233), and physical examinations (n = 676). Rates of skin test positivity were higher for males and differed between the groups (Gavião 43.0%, Suruí 52.8%, Zoró 68.1%), with a trend toward increase with age. Strong associations were also detected for the presence of suggestive ACL scars, on the one hand, and age, sex, and tribal affiliation, on the other. Although 14.7% of the subjects showed typical scars of past ACL disease, only 3 cases of active primary leishmanial ulcers were observed. The results did not indicate any clear association between seropositivity and positivity to the Montenegro intradermal test or presence of scars. The authors discuss the epidemiology of ACL in the Tupí-Mondé in the light of their ecology and recent history.

The effect of creatine supplementation upon inflammatory and muscle soreness markers after a 30km race.

We have evaluated the effect of a creatine supplementation protocol upon inflammatory and muscle soreness markers: creatine kinase (CK), lactate dehydrogenase (LDH), prostaglandin E2) (PGE2) and tumor necrosis factor-alpha (TNF-alpha) after running 30km. Runners with previously experience in running marathons, with their personal best between 2.5-3h were supplemented for 5 days prior to the 30km race with 4 doses of 5g of creatine and 15g of maltodextrine per day while the control group received the same amount of maltodextrine. Pre-race blood samples were collected immediately before running the 30km, and 24h after the end of the test (the post-race samples). After the test, athletes from the control group presented an increase in plasma CK (4.4-fold), LDH (43%), PGE2 6.6-fold) and TNF-alpha (2.34-fold) concentrations, indicating a high level of cell injury and inflammation. Creatine supplementation attenuated the changes observed for CK (by 19%), PGE2 and TNF-alpha (by 60.9% and 33.7%, respectively, p<0.05) and abolished the increase in LDH plasma concentration observed after running 30km, The athletes did not present any side effects such as cramping, dehydration or diarrhea, neither during the period of supplementation, nor during the 30km race. All the athletes finished the race in a time equivalent to their personal best +/- 5.8%. These results indicate that creatine supplementation reduced cell damage and inflammation after an exhaustive intense race.

Hepatitis B epidemiology and cultural practices in Amerindian populations of Amazonia: the Tupí-Mondé and the Xavánte from Brazil.

Hepatitis B infection and disease are highly endemic in South America. Prevalences of positivity are particularly high in Amazonia, and among Amerindian peoples in particular. This paper reports the results of a seroepidemiological survey for hepatitis B virus (HBV) carried out among four Amerindian populations from the Brazilian Amazon region: Gavião, Surui, Zoro and Navate. Rates of positivity to HBV serological markers (HBsAg, anti-HBs and or anti-HBc) are very high for the four groups, ranging from 62.8 to 95.7%. It is argued that the high rates of positivity in the Amerindian groups dealt with in this study, as well as for other Amazonian populations, are related to a complex of cultural practices which enhance the likelihood of HBV transmission (bloodletting, scarification, tattooing and orally processed food, among others). The authors suggest that, due to unique patterns of interaction between sociocultural and environmental factors. HBV infection assumes a specific profile in native Amazonian societies.

Mitochondrial DNA polymorphism in three Brazilian Indian tribes.

The first 360 base pairs of the mitochondrial DNA (mtDNA) major noncoding region from 82 individuals affiliated with the Brazilian Xavante, Zoró and Gavião tribes were sequenced. A total of 14 different lineages were observed, the largest number (8) being found among the Zoró. The latter share five lineages with the Gavião (who are their neighbors and are culturally similar to them), but only one with the Xavante. The lineages can be grouped into four clusters, previously identified by other authors. The 9 base pair deletion characteristic of Asian and Pacific populations occurs in 32% of the individuals, whose mtDNA was classified in five lineages, all grouped in one of the four clusters. Nucleotide diversity, as evaluated by three indices, are not much different from those observed in Indians from Central and North America, despite the fact that the Xavante consistently show lower numbers. These results do not confirm previous generalizations about the genetic diversity of Amerindians, and the need for additional studies in this system is stressed. © 1996 Wiley-Liss, Inc.