814 resultados para Sleep homeostasis


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The double journey (work and study) may result or aggravate health problems, including sleep disturbances, as observed in previous studies with high school students. The aim of this study is to analyze the sleep-wake cycle and perceived sleepiness of working college students during weekdays. Twenty-three healthy college male students, 21-24 years old, working during the day and attending classes in the evening, participated in this study. During five consecutive days, the students filled out daily activities logs and wore actigraphs. Mean sleeping time was lower than 6 hours per night. No significant differences were observed in the sleep-wake cycle during the weekdays. The observed lack of changes in the sleep-wake cycle of these college students might occur as participants were not on a free schedule, but exposed to social constraints, as was the regular attendance to evening college and day work activities. Sleepiness worsened over the evening school hours. Those results show the burden carried by College students who perform double activities - work and study.

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We aimed to investigate the possible role of creatine (CR) supplementation in counteracting dexamethasone-induced muscle wasting and insulin resistance in rats. Also, we examined whether CR intake would modulate molecular pathways involved in muscle remodeling and insulin signaling. Animals were randomly divided into four groups: (1) dexamethasone (DEX); (2) control pair-fed (CON-PF); (3) dexamethasone plus CR (DEX-CR); and (4) CR pair-fed (CR-PF). Dexamethasone (5 mg/kg/day) and CR (5 g/kg/day) were given via drinking water for 7 days. Plantaris and extensor digitorum longus (EDL) muscles were removed for analysis. Plantaris and EDL muscle mass were significantly reduced in the DEX-CR and DEX groups when compared with the CON-PF and CR-PF groups (P < 0.05). Dexamethasone significantly decreased phospho-Ser(473)-Akt protein levels compared to the CON-PF group (P < 0.05) and CR supplementation aggravated this response (P < 0.001). Serum glucose was significantly increased in the DEX group when compared with the CON-PF group (DEX 7.8 +/- A 0.6 vs. CON-PF 5.2 +/- A 0.5 mmol/l; P < 0.05). CR supplementation significantly exacerbated hyperglycemia in the dexamethasone-treated animals (DEX-CR 15.1 +/- A 2.4 mmol/l; P < 0.05 vs. others). Dexamethasone reduced GLUT-4 translocation when compared with the CON-PF and CR-PF (P < 0.05) groups and this response was aggravated by CR supplementation (P < 0.05 vs. others). In conclusion, supplementation with CR resulted in increased insulin resistance and did not attenuate muscle wasting in rats treated with dexamethasone. Given the contrast with the results of human studies that have shown benefits of CR supplementation on muscle atrophy and insulin sensitivity, we suggest caution when extrapolating this animal data to human subjects.

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Background: Lymphangioleiomyomatosis (LAM) is characterised by progressive airway obstruction and hypoxaemia in young women. Although sleep may trigger hypoxaemia in patients with airway obstruction, it has not been previously investigated in patients with LAM. Methods: Consecutive women with lung biopsy proven LAM and absence of hypoxaemia while awake were evaluated with pulmonary function test, echocardiography, 6-min walk test, overnight full polysomnography, and Short Form 36 health-related quality-of-life questionnaire. Results: Twenty-five patients with (mean +/- SD) age 45 +/- 10 years, SpO(2) awake 95% +/- 2, forced expiratory volume in the first second (median-interquartile) FEV1 (% predicted) 77 (47-90) and carbonic monoxide diffusion capacity, DLCO (%) 55 (34-74) were evaluated. Six-minute walk test distance and minimum SpO(2) (median-interquartile) were, respectively, 447 m (411 -503) and 90% (82-94). Median interquartile apnoea-hypopnoea index was in the normal range 2 (1-5). Fourteen patients (56%) had nocturnal hypoxaemia (10% total sleep time with SpO(2) <90%), and the median sleep time spent with SpO(2) <90% was 136 (13-201) min. Sleep time spent with SpO(2) <90% correlated with the residual volume/total lung capacity ratio (r(s) = 0.5, p: 0.02), DLCO (r(s) = -0.7, p: 0.001), FEV1 (r(s) = -0.6, p: 0.002). Multivariate linear regression model showed that RV/TLC ratio was the most important functional variable related to sleep hypoxaemia. Conclusion: Significant hypoxaemia during sleep is common in LAM patients with normal SpO(2) while awake, especially among those with some degree of hyperinflation in lung function tests. (C) 2011 Published by Elsevier Ltd.

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The transcription factor B lymphocyte induced maturation protein-1 (Blimp-1) plays important roles in embryonic development and immunity. Blimp-1 is required for the differentiation of plasma cells, and mice with T cell specific deletion of Blimp-1 (Blimp-1CKO mice) develop a fatal inflammatory response in the colon. Previous work demonstrated that lack of Blimp-1 in CD4(+) and CD8(+) T cells leads to intrinsic functional defects, but little is known about the functional role of Blimp-1 in regulating differentiation of Th cells in vivo and their contribution to the chronic intestinal inflammation observed in the Blimp1CKO mice. In this study, we show that Blimp-1 is required to restrain the production of the inflammatory cytokine IL-17 by Th cells in vivo. Blimp-1CKO mice have greater numbers of IL-17 producing TCR beta(+)CD4(+)cells in lymphoid organs and in the intestinal mucosa. The increase in IL-17 producing cells was not restored to normal levels in wild-type and Blimp-1CKO mixed bone marrow chimeric mice, suggesting an intrinsic role for Blimp-1 in constraining the production of IL-17 in vivo. The observation that Blimp-1 deficient CD4(+) T cells are more prone to differentiate into IL-17(+)/IFN-gamma(+) cells and cause severe colitis when transferred to Rag1-deficient mice provides further evidence that Blimp-1 represses IL-17 production. Analysis of Blimp-1 expression at the single cell level during Th differentiation reveals that Blimp-1 expression is induced in Th1 and Th2 but repressed by TGF-beta in Th17 cells. Collectively, the results described here establish a new role for Blimp-1 in regulating IL-17 production in vivo. The Journal of Immunology, 2012,189: 5682-5693.

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Objective: - To develop and test a practical clinical method to assess frailty in nursing homes; - To investigate the relationship between cognitive status of the elderly and the balance between water compartments of their body composition. Design and subjects: Cross-sectional study, conducted at two nursing homes in Boston-MA. Methods: Body mass and height (Ht) were evaluated to calculate BMI (body mass index, in Kg/m(2)). The cognitive decline was evaluated based on the scores obtained from the Mini-Mental State Examination (MMSE); The extracellular to total body water ratio (ECW/TBW) was calculated after the analysis of TBW from deuterium and tritium dilution and ECW from bromide dilution. Single-frequency BIA analysis data were investigated for resistance (R) and reactance (Xc), plotted in an R/Ht Xc/Ht graph (vectorial analysis-BIVA). The BIVA results of nursing home residents were compared against the data obtained from the NHANES Ill study. TBW and ECW values were compared with a group of free-living elderly volunteers. Results: The ECW/TBW was significantly higher in nursing home residents than in the free-living individuals. BIVA analysis showed significantly higher Xc/Ht values in the reference subjects. The MMSE did not present a significant correlation with ECW/TBW for either gender. Conclusion: We proposed the ECW/TBW ratio and BIVA as surrogate methods for the clinical assessment of frailty. We tested successfully both approaches with nursing home patients and free-living volunteers and compared them to a national data base. The advent of new, portable instruments will enable field tests to further validate our proposed "Frailty Factor" in future studies. We found no correlation between frailty and cognitive decline in the nursing home.

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Dettoni JL, Consolim-Colombo FM, Drager LF, Rubira MC, de Souza SB, Irigoyen MC, Mostarda C, Borile S, Krieger EM, Moreno H Jr, Lorenzi-Filho G. Cardiovascular effects of partial sleep deprivation in healthy volunteers. J Appl Physiol 113: 232-236, 2012. First published April 26, 2012; doi: 10.1152/japplphysiol.01604.2011.-Sleep deprivation is common in Western societies and is associated with increased cardiovascular morbidity and mortality in epidemiological studies. However, the effects of partial sleep deprivation on the cardiovascular system are poorly understood. In the present study, we evaluated 13 healthy male volunteers (age: 31 +/- 2 yr) monitoring sleep diary and wrist actigraphy during their daily routine for 12 nights. The subjects were randomized and crossover to 5 nights of control sleep (>7 h) or 5 nights of partial sleep deprivation (<5 h), interposed by 2 nights of unrestricted sleep. At the end of control and partial sleep deprivation periods, heart rate variability (HRV), blood pressure variability (BPV), serum norepinephrine, and venous endothelial function (dorsal hand vein technique) were measured at rest in a supine position. The subjects slept 8.0 +/- 0.5 and 4.5 +/- 0.3 h during control and partial sleep deprivation periods, respectively (P < 0.01). Compared with control, sleep deprivation caused significant increase in sympathetic activity as evidenced by increase in percent low-frequency (50 +/- 15 vs. 59 +/- 8) and a decrease in percent high-frequency (50 +/- 10 vs. 41 +/- 8) components of HRV, increase in low-frequency band of BPV, and increase in serum norepinephrine (119 +/- 46 vs. 162 +/- 58 ng/ml), as well as a reduction in maximum endothelial dependent venodilatation (100 +/- 22 vs. 41 +/- 20%; P < 0.05 for all comparisons). In conclusion, 5 nights of partial sleep deprivation is sufficient to cause significant increase in sympathetic activity and venous endothelial dysfunction. These results may help to explain the association between short sleep and increased cardiovascular risk in epidemiological studies.

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Study objectives: The purpose of the present study was to evaluate the relationship between sleep duration and dietary habits in elderly obese patients treated at an institute of cardiology. Methods: The fifty-eight volunteers were elderly patients with obesity (classified as obese according to BMI) of both genders, between 60 and 80 years of age. All participants were subjected to assessments of food intake, anthropometry, level of physical activity, and duration of sleep. Results: The men had significantly greater weight, height, and waist circumference than women. Sleep durations were correlated with dietary nutrient compositions only in men. We found a negative association between short sleep and protein intake (r = -0.43; p = 0.02), short sleep and monounsaturated fatty acids intake (r = -0.40; p = 0.03), and short sleep and cholesterol dietary intake (r = -0.50; p = 0.01). Conclusions: We conclude that mainly in men, volunteers that had short sleep duration showed a preference for high energy-density as fatty food, at least in part, may explain the relationship between short sleep duration and the development of metabolic abnormalities.

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OBJECTIVE: Obstructive sleep apnea is frequent during the acute phase of stroke, and it is associated with poorer outcomes. A well-established relationship between supine sleep and obstructive sleep apnea severity exists in non-stroke patients. This study investigated the frequency of supine sleep and positional obstructive sleep apnea in patients with ischemic or hemorrhagic stroke. METHODS: Patients who suffered their first acute stroke, either ischemic or hemorrhagic, were subjected to a full polysomnography, including the continuous monitoring of sleep positions, during the first night after symptom onset. Obstructive sleep apnea severity was measured using the apnea-hypopnea index, and the NIHSS measured stroke severity. RESULTS: We prospectively studied 66 stroke patients. The mean age was 57.6+/-11.5 years, and the mean body mass index was 26.5+/-4.9. Obstructive sleep apnea (apnea-hypopnea index >= 5) was present in 78.8% of patients, and the mean apnea-hypopnea index was 29.7+/-26.6. The majority of subjects (66.7%) spent the entire sleep time in a supine position, and positional obstructive sleep apnea was clearly present in the other 23.1% of cases. A positive correlation was observed between the NIHSS and sleep time in the supine position (r(s) = 0.5; p<0.001). CONCLUSIONS: Prolonged supine positioning during sleep was highly frequent after stroke, and it was related to stroke severity. Positional sleep apnea was observed in one quarter of stroke patients, which was likely underestimated during the acute phase of stroke. The adequate positioning of patients during sleep during the acute phase of stroke may decrease obstructive respiratory events, regardless of the stroke subtype.

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OBJECTIVE: Poor sleep quality is one of the factors that adversely affects patient quality of life after kidney transplantation, and sleep disorders represent a significant cardiovascular risk factor. The objective of this study was to investigate the prevalence of changes in sleep quality and their outcomes in kidney transplant recipients and analyze the variables affecting sleep quality in the first years after renal transplantation. METHODS: Kidney transplant recipients were evaluated at two time points after a successful transplantation: between three and six months (Phase 1) and between 12 and 15 months (Phase 2). The following tools were used for assessment: the Pittsburgh Sleep Quality Index; the quality of life questionnaire Short-Form-36; the Hospital Anxiety and Depression scale; the Karnofsky scale; and assessments of social and demographic data. The prevalence of poor sleep was 36.7% in Phase 1 and 38.3% in Phase 2 of the study. RESULTS: There were no significant differences between patients with and without changes in sleep quality between the two phases. We found no changes in sleep patterns throughout the study. Both the physical and mental health scores worsened from Phase 1 to Phase 2. CONCLUSION: Sleep quality in kidney transplant recipients did not change during the first year after a successful renal transplantation.

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The Kallikrein-Kinin System (KKS) has been implicated in several aspects of metabolism, including the regulation of glucose homeostasis and adiposity. Kinins and des-Arg-kinins are the major effectors of this system and promote their effects by binding to two different receptors, the kinin B2 and B1 receptors, respectively. To understand the influence of the KKS on the pathophysiology of obesity and type 2 diabetes (T2DM), we generated an animal model deficient for both kinin receptor genes and leptin (obB1B2KO). Six-month-old obB1B2KO mice showed increased blood glucose levels. Isolated islets of the transgenic animals were more responsive to glucose stimulation releasing greater amounts of insulin, mainly in 3-month-old mice, which was corroborated by elevated serum C-peptide concentrations. Furthermore, they presented hepatomegaly, pronounced steatosis, and increased levels of circulating transaminases. This mouse also demonstrated exacerbated gluconeogenesis during the pyruvate challenge test. The hepatic abnormalities were accompanied by changes in the gene expression of factors linked to glucose and lipid metabolisms in the liver. Thus, we conclude that kinin receptors are important for modulation of insulin secretion and for the preservation of normal glucose levels and hepatic functions in obese mice, suggesting a protective role of the KKS regarding complications associated with obesity and T2DM.

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We previously observed that hypoxia is an important component of host microenvironments during pulmonary fungal infections. However, mechanisms of fungal growth in these in vivo hypoxic conditions are poorly understood. Here, we report that mitochondrial respiration is active in hypoxia (1% oxygen) and critical for fungal pathogenesis. We generated Aspergillus fumigatus alternative oxidase (aoxA) and cytochrome C (cycA) null mutants and assessed their ability to tolerate hypoxia, macrophage killing and virulence. In contrast to ?aoxA, ?cycA was found to be significantly impaired in conidia germination, growth in normoxia and hypoxia, and displayed attenuated virulence. Intriguingly, loss of cycA results in increased levels of AoxA activity, which results in increased resistance to oxidative stress, macrophage killing and long-term persistence in murine lungs. Thus, our results demonstrate a previously unidentified role for fungal mitochondrial respiration in the pathogenesis of aspergillosis, and lay the foundation for future research into its role in hypoxia signalling and adaptation.

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The concept of need for recovery from work (NFR) was deduced from the effort recuperation model. In this model work produces costs in terms of effort during the working day. When there is enough time and possibilities to recuperate, a worker will arrive at the next working day with no residual symptoms of previous effort. NFR evaluates work characteristics such as psychosocial demands, professional work hours or schedules. However, sleep may be an important part of the recovery process. The aim of the study was to test the association between sleep-related complaints and NFR. A cross-sectional study was carried out at three hospitals. All females nursing professionals engaged in assistance to patients were invited to participate (N=1,307). Participants answered a questionnaire that included four sleep-related complaints (insomnia, unsatisfactory sleep, sleepiness during work hours and insufficient sleep), work characteristics and NRF scale. Binomial logistic regression analysis showed that all sleep-related complaints are associated with a high need for recovery from work. Those who reported insufficient sleep showed a greater chance of high need for recovery; OR=2.730 (CI 95% 2.074-3.593). These results corroborate the hypothesis that sleep is an important aspect of the recovery process and, therefore, should be thoroughly investigated.

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Introduction: This paper examines the various factors that contribute to the occurrence of sleep alterations during peri and post climacteric and thus produce significant imperil to women's quality of life. Among the probable causes of insomnia or sleep disorders associated to climacteric stand out the occurrence of vasomotor symptoms, depressive state and respiratory distress during sleep, such as sleep apnea, along with chronic pain, although psychosocial factors related to the climacteric bear major influence on such clinical status. Method: The bibliographic analysis was carried out using several electronic data base namely: Cochrane, Medline, Embase, Bni Plus, Biological Abstracts, Psycinfo, Web Of Science, Sigle, Dissertation Abstracts and ZETOC published in English, Spanish and Poruguese. The key terms used were: sleep, REM sleep, slow wave sleep polysomnography; electroencephalogram; sleep disturbances; disturbances of sleep onset and maintenance; excessive somnolence disturbances; climacteric; menopause; depression; neurobiology; biologic models; circadian rhythm; mental health and epidemiology. Case studies and letters to the editor were excluded. The summaries of the identified studies found in the data base were analyzed and assessed, and the data analyzed separately according to the subjective or objective criteria for data collection. Results: The climacteric transition constitutes a period of major risk for the development of depressive, vasomotor and insomnia symptoms although not caused solely by hypoestrogenism. The diagnostic methods used in the study of sleep disorders range from subjective assessment by means of response to specific questionnaires to the objective analysis of actigraphic or polissonographic daytime and nocturnal reports. Polissonographic studies of the whole night, performed at the laboratory, are the golden method of choice for diagnostic of sleep disorders. Studies point to the high prevalence of sleep disorders in the climacteric, especially insomnia, apnea and periodic movement of legs and also to the fact that this phase of life presents decrease in the quality of sleep. Women in peri and post climacteric show higher sleep latency and difficulty in its maintenance and refer being less satisfied with its quality even when compared to those who are not climacteric. Exception made to the vasomotor symptomatology, the other climacteric complaints such as mood disturbances, libido alterations, cognitive deficit, articular pain and sleep disorders are markedly associated to psychosocial factors, lifestyle and especially to women's perception of what the climacteric means to their lives. Conclusion: The analysis of the available studies revealed a proneness to deterioration of quality of life of climacteric women markedly in the sleep disturbances, depressed mood and anxiety domains and should not to be basically attributed to the climacteric. It is necessary that the professionals consider the need of assessment of such pathologies as complex phenomena and the literature lacks studies contemplating such dimensions.

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The objective of this study was to verify the effect of acupuncture on the sleep quality of obese workers in a teaching hospital. Data were collected from July to October 2009, focusing on 37 workers who attended eight weekly acupuncture sessions. The Pittsburgh Sleep Quality Index was used to assess their sleep quality before and after the intervention. Results show that before the intervention, five (13.5%) people experienced good quality of sleep whereas at the end of the study 14 (37.8%) showed this condition. Statistic significance (p=0.0001) was found in comparing the mean scores obtained before and after acupuncture. Acupuncture had effects on the quality of sleep in the studied sample, presenting itself as a complementary technique for treating sleep disorders and consequently improving the quality of life in this population.

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Dexamethasone (DEXA) is a potent immunosupressant and anti-inflammatory agent whose main side effects are muscle atrophy and insulin resistance in skeletal muscles. In this context, leucine supplementation may represent a way to limit the DEXA side effects. In this study, we have investigated the effects of a low and a high dose of leucine supplementation (via a bolus) on glucose homeostasis, muscle mass and muscle strength in energy-restricted and DEXA-treated rats. Since the leucine response may also be linked to the administration of this amino acid, we performed a second set of experiments with leucine given in bolus (via gavage) versus leucine given via drinking water. Leucine supplementation was found to produce positive effects (e. g., reduced insulin levels) only when administrated in low dosage, both via the bolus or via drinking water. However, under DEXA treatment, leucine administration was found to significantly influence this response, since leucine supplementation via drinking water clearly induced a diabetic state, whereas the same effect was not observed when supplied via the gavage.