Free-running circadian rhythms of muscle strength, reaction time, and body temperature in totally blind people.

Light is the major synchronizer of circadian rhythms. In the absence of light, as for totally blind people, some variables, such as body temperature, have an endogenous period that is longer than 24 h and tend to be free running. However, the circadian rhythm of muscle strength and reaction time in totally blind people has not been defined in the literature. The objective of this study was to determine the period of the endogenous circadian rhythm of the isometric and isokinetic contraction strength and simple reaction time of totally blind people. The study included six totally blind people with free-running circadian rhythms and four sighted people (control group). Although the control group required only a single session to determine the circadian rhythm, the blind people required three sessions to determine the endogenous period. In each session, isometric strength, isokinetic strength, reaction time, and body temperature were collected six different times a day with an interval of at least 8 h. The control group had better performance for strength and reaction time in the afternoon. For the blind, this performance became delayed throughout the day. Therefore, we conclude that the circadian rhythms of strength and simple reaction time of totally blind people are within their free-running periods. For some professionals, like the blind paralympic athletes, activities that require large physiological capacities in which the maximum stimulus should match the ideal time of competition may result in the blind athletes falling short of their expected performance under this free-running condition.

Evaluation of periodic limb movements in a putative animal model of restless leg syndrome.

Restless leg syndrome (RLS) is a major healthcare burden with increasing prevalence. It has been demonstrated that periodic limb movements (PLM) can occur as an isolated phenomenon, but they are often associated with this syndrome and are the only symptom of this disorder that can be measured electrophysiologically. The aim of this study was to examine the sleep-wake behavior and the presence of limb movement in a rat model of RLS induced by lesioning the A11 dopaminergic nuclei with the neurotoxin 6-hydroxydopamine (6-OHDA). Rats were implanted with electrodes for electrocorticography and electromyography. Sleep recordings were monitored during light/dark periods lasting 12 hours each and were evaluated on days 7, 15, and 28 after injection of the drug or phosphate-buffered saline (PBS). A control group that did not receive any injection was also included. Wakefulness percentages were generated for 4-hour segments of the dark period, yielding the following 3 bins: 7 PM to 11 PM, 11 PM to 3 AM, and 3 PM to 7 PM. Additionally, slow wave sleep, paradoxical sleep, wakefulness, and limb movements were evaluated over the entire 12 hours of the light/dark cycle. All A11-lesioned rats exhibited an increased percentage of wakefulness during the last block of the dark period, as would be expected for an animal model of this syndrome. In addition, at all time points after lesioning, these animals presented increased frequencies of limb movement during both the light and the dark periods. These alterations were reversed by the acute administration of the dopaminergic agonist pramipexole. This animal model strengthens the notion that 6-OHDA-induced A11 lesions can be a valid animal model for RLS and PLM.

Effects of home-based exercise training for patients with chronic heart failure and sleep apnoea: a randomized comparison of two different programmes.

OBJECTIVE: To evaluate the effects of home-based exercise for patients with chronic heart failure and sleep apnoea and to compare two different training programmes. DESIGN: A randomized, prospective controlled trial. SETTING: Department of Cardiology, University Hospital, Brazil. SUBJECTS: Fifty chronic heart failure patients with sleep apnoea were randomized in three groups: Group 1 (aerobic training, n = 18), Group 2 (aerobic with strength training, n = 18), and Group 3 (untrained, n = 14). INTERVENTIONS: The training programme for Groups 1 and 2 began with three supervised exercise sessions, after they underwent three months of home-based exercise. Patients were followed by weekly telephone call and were reviewed monthly. Group 3 had the status of physical activity evaluated weekly by interview to make sure they remained untrained. MAIN OUTCOME MEASURES: At baseline and after three months: cardiopulmonary exercise testing, isokinetic strength and endurance, Minnesota living with heart failure questionnaire and polysomnography. Adherence was evaluated weekly. RESULTS: Of the 50 patients enrolled in the study, 45 completed the programme. Clinical events: Group 1 (one death), Group 2 (one myocardial infarction), Group 3 (one death and two strokes). None were training related. Training groups showed improvement in all outcomes evaluated and the adherence was an important factor (Group 1 = 98.5% and Group 2 = 100.2%, P = 0.743). Untrained Group 3 demonstrated significant decrease or no change on measurements after three months without training. CONCLUSION: Home-based exercise training is an important therapeutic strategy in chronic heart failure patients with sleep apnoea, and strength training resulted in a higher increase in muscle strength and endurance.

Can physical exercise have a protective effect in an animal model of sleep-related movement disorder?

The purpose of the present study was to determine whether physical exercise (PE) has a protective effect in an experimental animal model of sleep-related movement disorder (A11 dopaminergic nuclei lesions with 6-OHDA). Rats were divided into four groups (Control PE-CTRL/PE, SHAM/PE, A11 lesion/NPE, A11 lesion/PE). Two experiments were performed: (1) the rats underwent PE before (2 weeks) and after (4 weeks) the A11 lesion; and (2) the rats underwent PE only after (4 weeks) the A11 lesion. Electrode insertion surgery was performed and sleep analyses were conducted over a period of 24h (baseline and after PE) and analyzed in 6 blocks of 4h. The results demonstrated that the A11 lesion produced an increased percentage of wakefulness in the final block of the dark period (3-7am) and a significant enhancement of the number of limb movements (LM) throughout the day. Four weeks of PE was important for reducing the number of LMs in the A11 lesion group in the rats that performed PE before and after the A11 lesion. However, in the analysis of the protective effect of PE on LM, the results showed that the number of LMs was lower at baseline in the group that had performed 2 weeks of PE prior to the A11 lesion than in the group that had not previously performed PE. In conclusion, these findings consistently demonstrate that non-pharmacological manipulations had a beneficial effect on the symptoms of sleep-related movement disorder.

Spontaneously hypertensive rats: possible animal model of sleep-related movement disorders.

Clinical experience suggests that restless legs syndrome (RLS), periodic leg movement (PLM), and attention-deficit hyperactivity disorder (ADHD) may co-occur in both children and adults. The purpose of the present study was to provide an electrocorticography and electromyography evaluation of the spontaneously hypertensive rat (SHR) to investigate the potential of this rat strain as an animal model of RLS-PLM. Initial work focused on evaluating sleep patterns and limb movements during sleep in SHR, having normotensive Wistar rats (NWR) as control, followed by comparison of two treatments (pharmacological-dopaminergic agonist treatment and nonpharmacological-chronic physical exercise), known to be clinically beneficial for sleep-related movement disorders. The captured data strengthen the association between SHR and RLS-PLM, revealing a significant reduction on sleep efficiency and slow wave sleep and an increase on wakefulness and limb movements for the SHR group during the dark period, as compared to the NWR group, effects that have characteristics that are strikingly consistent with RLS-PLM. The pharmacological and nonpharmacological manipulations validated these results. The present findings suggest that the SHR may be a useful putative animal model to study sleep-related movement disorders mechanisms.

The effects of physical exercise on the serum iron profile in spontaneously hypertensive rats.

The purpose of this study was to evaluate the profile of serum iron in spontaneously hypertensive rats after an aerobic physical exercise. To accomplish this, 12 normotensive Wistar rats and 12 spontaneously hypertensive rats were distributed into "physical exercise" and "no physical exercise" groups. The animals in the physical exercise group underwent to an aerobic exercise for a total of 4 weeks. Blood was collected for the analysis of iron. Our results indicate that rats of the physical exercise group had significantly lower serum iron levels after the aerobic exercise protocol compared to the spontaneously hypertensive rats no physical exercise group (F ((3,16)) = 4.4915, p < 0.01). No significant difference was found between no physical exercise groups. The results indicated that the difference in iron may be due to an increased demand for iron, prompted by chronic physical exercise. In addition, erythrocytosis has been associated with increased blood pressure in spontaneously hypertensive rats, suggesting that iron reduction may be related to decreased blood pressure in these animals.

Leucemia e residência próxima a postos de combustíveis: estudo exploratório na Cidade de São Paulo / Leukemia and Residence near to Gas stations: An Exploratory Study in São Paulo

Hidrocarbonetos aromáticos são encontrados naturalmente no ambiente, emesmo em baixas concentrações, exibem propriedades mutagênicas e/oupró-carcinogênicas para os seres humanos. O benzeno ocorre naturalmenteno petróleo bruto e como conseqüência, é um componente da gasolina.Também é formado durante a combustão incompleta de combustíveis fósseis(derivados de petróleo, carvão, e, em menor medida, madeira). Alémdisso, é um intermediário comercialmente importantes na fabricação demuitos produtos químicos.Apesar das emissões provenientes da gasolina e da indústria petroquímica,as quais são as principais fontes de benzeno para o ar ambiente, há umavasta gama de potenciais fontes deste composto, ainda que em baixas concentrações,dentro das residências. Por exemplo, materiais de construção ecertos materiais de decoração podem conter concentrações residuais debenzeno. Outras fontes potenciais residenciais incluem a fumaça do tabaco,as tintas e removedores de tintas, fogões a lenha, calefação, etc.Por ser volátil, a inalação é a via de exposição mais comum para a população,mas o benzeno também penetra rapidamente pela pele e pode contaminara água e alimentos, resultando em vias de exposição dérmica e por ingestão...

As lesöes por esforços repetitivos e seus riscos: uma experiência com bancários / Repetitive strain injury and its risks: experience with bank-cluks

Apresenta e discute conhecimentos científicos atuais sobre as "Lesöes por Esforços Repetitivos" (L.E.R.), dados relativos ao posicionamento de um grupo de bancários estudado sobre as condiçöes de trabalho e as L.E.R., na tentativa de contribuir, dentro desse aspecto específico, para a conscientizaçäo do problema e uma busca coletiva de soluçöes