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Query: UMLS:C0015672 (fatigue)
 51,768 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Repeated activation of skeletal muscle causes fatigue, which involves a reduced ability to produce force and slowed contraction regarding both the speed of shortening and relaxation. One important component in skeletal muscle fatigue is a reduced sarcoplasmic reticulum (SR) Ca2+ release. In the present review we will describe different types of fatigue-induced inhibition of SR Ca2+ release. We will focus on a type of long-lasting failure of SR Ca2+ release which is called low-frequency fatigue, because this type of fatigue may be involved in the muscle dysfunction and chronic pain experienced by computer workers. Paradoxically it appears that the Ca2+ released from the SR, which is required for contraction, may actually be responsible for the failure of SR Ca2+ release during low-frequency fatigue. We will also discuss the relationship between gross morphological changes in muscle fibres and long-lasting failure of SR Ca2+ release. Finally, a model linking muscle cell dysfunction and muscle pain is proposed.
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PMID:Functional significance of Ca2+ in long-lasting fatigue of skeletal muscle. 1110 57

Chronic fatigue syndrome (CFS) is a debilitating condition. Approximately 75% of sufferers are women. The etiology of CFS is debated, but remains inconclusive. "Fatigue" is ill defined and conceptually problematic. The international multidisciplinary literature on CFS reveals a paucity of studies on women. Qualitative research to analyze women's discourses on CFS is virtually absent. Eleven New Zealand women of European descent with experience of CFS were interviewed in depth. Within the complex facets of CFS, this article reports specifically on an analysis of discourses on "fatigue." The predominant theme that emerged was that fatigue is articulated as "lack" or absence, which is not representable as an identifiable entity in biomedical terms. Parallels with chronic pain are briefly drawn. We conclude that approaches to CFS must respond to the diverse and complex constructions of the experience of fatigue evident in women's narratives.
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PMID:Fatigue in chronic fatigue syndrome: a discourse analysis of women's experiential narratives. 1111 65

The brain and the immune system are the two major adaptive systems of the body. During an immune response the brain and the immune system "talk to each other" and this process is essential for maintaining homeostasis. Two major pathway systems are involved in this cross-talk: the hypothalamic-pituitary-adrenal (HPA) axis and the sympathetic nervous system (SNS). This overview focuses on the role of SNS in neuroimmune interactions, an area that has received much less attention than the role of HPA axis. Evidence accumulated over the last 20 years suggests that norepinephrine (NE) fulfills the criteria for neurotransmitter/neuromodulator in lymphoid organs. Thus, primary and secondary lymphoid organs receive extensive sympathetic/noradrenergic innervation. Under stimulation, NE is released from the sympathetic nerve terminals in these organs, and the target immune cells express adrenoreceptors. Through stimulation of these receptors, locally released NE, or circulating catecholamines such as epinephrine, affect lymphocyte traffic, circulation, and proliferation, and modulate cytokine production and the functional activity of different lymphoid cells. Although there exists substantial sympathetic innervation in the bone marrow, and particularly in the thymus and mucosal tissues, our knowledge about the effect of the sympathetic neural input on hematopoiesis, thymocyte development, and mucosal immunity is extremely modest. In addition, recent evidence is discussed that NE and epinephrine, through stimulation of the beta(2)-adrenoreceptor-cAMP-protein kinase A pathway, inhibit the production of type 1/proinflammatory cytokines, such as interleukin (IL-12), tumor necrosis factor-alpha, and interferon-gamma by antigen-presenting cells and T helper (Th) 1 cells, whereas they stimulate the production of type 2/anti-inflammatory cytokines such as IL-10 and transforming growth factor-beta. Through this mechanism, systemically, endogenous catecholamines may cause a selective suppression of Th1 responses and cellular immunity, and a Th2 shift toward dominance of humoral immunity. On the other hand, in certain local responses, and under certain conditions, catecholamines may actually boost regional immune responses, through induction of IL-1, tumor necrosis factor-alpha, and primarily IL-8 production. Thus, the activation of SNS during an immune response might be aimed to localize the inflammatory response, through induction of neutrophil accumulation and stimulation of more specific humoral immune responses, although systemically it may suppress Th1 responses, and, thus protect the organism from the detrimental effects of proinflammatory cytokines and other products of activated macrophages. The above-mentioned immunomodulatory effects of catecholamines and the role of SNS are also discussed in the context of their clinical implication in certain infections, major injury and sepsis, autoimmunity, chronic pain and fatigue syndromes, and tumor growth. Finally, the pharmacological manipulation of the sympathetic-immune interface is reviewed with focus on new therapeutic strategies using selective alpha(2)- and beta(2)-adrenoreceptor agonists and antagonists and inhibitors of phosphodiesterase type IV in the treatment of experimental models of autoimmune diseases, fibromyalgia, and chronic fatigue syndrome.
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PMID:The sympathetic nerve--an integrative interface between two supersystems: the brain and the immune system. 1112 11

Chronic pain is associated with high rates of major depressive disorder (MDD), but somatic symptoms caused by pain may complicate the diagnosis of MDD. Different methods to address this issue include the adoption of an inclusive approach to diagnosis (i.e. including all symptoms when assessing MDD, regardless of their presumed cause), an etiologic approach (i.e. disregarding symptoms that are caused by medical problems), and a substitutive approach (i.e. replacing somatic symptoms with non-somatic alternatives). In this study, 129 patients with chronic pain (56 men and 73 women) underwent semi-structured interviews addressing 23 individual symptoms of MDD. Detailed probing was undertaken into patients' perceptions of the causes of those symptoms that could potentially be brought on by pain. We found that the prevalence of MDD was highest with the inclusive diagnostic method (35.7%), lowest with an etiologic approach that discounted symptoms based on patient attributions (19.4%), and intermediate with the substitutive method (30.3%). Although some symptoms, such as insomnia, fatigue, and difficulty concentrating, were reported by 34--53% of the patients who did not meet criteria for MDD, they were still more common among those who did (85--94%, P<0.001). Patients who met criteria for MDD with the inclusive method, but who did not meet criteria using the etiologic method, had Beck Depression Inventory scores (M=24.5) that were comparable to those of patients who were consistently classified with MDD across methods (M=25.6). These scores were much higher than those of patients who were consistently classified without MDD (M=13.8, P<0.001). In conclusion, excluding criterion symptoms that patients attribute to pain can reduce the observed prevalence of MDD by about 45%. However, this method introduces a problem of false-negative diagnoses that appears to be more significant than the problem of false positives associated with the inappropriate inclusion of somatic symptoms.
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PMID:Alternative diagnostic criteria for major depressive disorder in patients with chronic pain. 1127 78

Fibromyalgia (FM) is a complex syndrome, primarily of women, characterized by chronic pain, fatigue, and sleep disturbance. Altered function of the somatotropic axis has been documented in patients with FM, but little is known about nocturnal levels of PRL. As part of a laboratory study of sleep patterns in FM, we measured the serum concentrations of GH and PRL hourly from 2000--0700 h in a sample of 25 women with FM (mean, 46.9 +/- 7.6 yr) and in 21 control women (mean, 42.6 +/- 8.1 yr). The mean (+/-SEM ) serum concentrations (micrograms per L) of GH and of PRL during the early sleep period were higher in control women than in patients with FM [GH, 1.6 +/- 0.4 vs. 0.6 +/- 0.2 (P < 0.05); PRL, 23.2 +/- 2.2 vs. 16.9 +/- 2.0 (P < 0.025)]. The mean serum concentrations of GH and PRL increased more after sleep onset in control women than in patients with FM [GH, 1.3 +/- 0.4 vs. 0.3 +/- 0.2 (P < 0.05); PRL, 16.2 +/- 2.4 vs. 9.7 +/- 1.5 (P < 0.025)]. Sleep efficiency and amounts of sleep or wake stages on the blood draw night were not different between groups. There was a modest inverse relationship between sleep latency and PRL and a direct relationship between sleep efficiency and PRL in FM. There was an inverse relationship between age and GH most evident in control women. Insulin-like growth factor I levels were not different between the groups. These data demonstrate altered functioning of both the somatotropic and lactotropic axes during sleep in FM and support the hypothesis that dysregulated neuroendocrine systems during sleep may play a role in the pathophysiology of FM.
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PMID:Decreased nocturnal levels of prolactin and growth hormone in women with fibromyalgia. 1129 2

Many disability claims are based on the subjective symptom of fatigue, which can be caused by a wide spectrum of diagnoses including fibromyalgia, chronic fatigue syndrome and cardiopulmonary diseases. Chronic pain is very often a compounding problem. It is vital for every insurer to have fair and objective criteria to distinguish between invalid claims and those with merit. This review article proposes objective tools and parameters to achieve this goal.
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PMID:Assessing impairment and disability for syndromes presenting with chronic fatigue. 1151 May 14

Thought Field Therapy (TFT) is a self-administered treatment developed by psychologist Roger Callahan. TFT uses energy meridian treatment points and bilateral optical-cortical stimulation while focusing on the targeted symptoms or problem being addressed. The clinical applications of TFT summarized included anxiety, adjustment disorder with anxiety and depression, anxiety due to medical condition, anger, acute stress, bereavement, chronic pain, cravings, depression, fatigue, nausea, neurodermatitis, obsessive traits, panic disorder without agoraphobia, parent-child stress, phobia, posttraumatic stress disorder, relationship stress, trichotillomania, tremor, and work stress. This uncontrolled study reports on changes in self-reported Subjective Units of Distress (SUD; Wolpe, 1969) in 1,594 applications of TFT, treating 714 patients. Paired t-tests of pre- and posttreatment SUD were statistically significant in 31 categories reviewed. These within-session decreases of SUD are preliminary data that call for controlled studies to examine validity, reliability, and maintenance of effects over time. Illustrative case and heart rate variability data are presented.
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PMID:Thought Field Therapy clinical applications: utilization in an HMO in behavioral medicine and behavioral health services. 1152 9

1. The aim of this study was to examine degrees of cognitive behavioural effects of fatigue, mood changes and somatic responses to sleep loss in women with and without sufficient sleep, and to explore possible links between effects of sleep loss and specific sleep disturbances in selected groups. 2. A total 156 women working in a casualty department on different work shifts responded to a questionnaire which measured sleep quality, strain and symptoms related to working conditions, as well as effects of sleep loss. 3. About 40% of the women had perceived insufficient sleep during the last 6 months. They perceived significantly worse sleep quality and a higher degree of strain according to working conditions than the others. Palpitation and dysphoria as effects of sleep loss were independently predicted by sleep quality. Dysphoria was also predicted by difficulty in falling asleep. Cognitive behavioural effects of fatigue was predicted by disturbed sleep. Palpitation effects led to a 10-fold increase in the probability of cognitive behavioural effects of fatigue. The effects were most prominent among women suffering from gastrointestinal problems of long duration and chronic pain. 4. Responses to reduced sleep quality in women constitute a form of stress, with sympathetic activation, increased susceptibility to infection, moderate cognitive impairment, mood changes and somatic distress.
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PMID:Sleep quality and responses to insufficient sleep in women on different work shifts. 1190 28

Cross-sectional studies have consistently shown a relationship between chronic widespread pain, the clinical hallmark of fibromyalgia, and psychological distress. These studies cannot distinguish the direction of any causal relationship. Recent population based studies have reported that such pain is predictive of future distress. However, chronic pain is often associated with physical and psychological co-morbid features which may confound this relationship. The aim of this study was to examine the hypothesis that chronic widespread pain increases the risk of future distress after adjusting for the effects of possible confounding factors. A population based survey of 1953 individuals identified subjects' psychological status and whether they satisfied criteria for chronic widespread pain. At baseline co-morbid features of chronic widespread pain, including reporting other somatic symptoms, abnormal illness behaviour, health anxiety, fatigue and low levels of self-care, were measured. All subjects were followed up after 12 months to determine levels of psychological distress. Subjects with chronic widespread pain at baseline were much more likely to be distressed at follow up (OR=4.0, 95% CI (2.5,6.3)). As levels of distress at follow up may simply reflect those at baseline the association was adjusted for baseline levels of distress. Chronic widespread pain was, however, still associated with future distress although the relationship was slightly attenuated (odds ratio, OR=3.0, 95% CI (1.8,5.1)). To examine our main hypothesis a final analysis was undertaken adjusting this association for those co-morbid features assessed at baseline. Following these adjustments chronic widespread pain was no longer significantly associated with future distress (OR=1.5, 95% CI (0.8,2.9)). Chronic widespread pain was associated with increased levels of psychological distress at follow up. However, a more rigorous analysis indicated that the association between baseline pain status with future distress was explained by concomitant features of chronic pain rather than pain per se. These findings indicate that it is those persons with chronic widespread pain in the presence of other physical and psychosocial factors who will become distressed.
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PMID:Does chronic pain predict future psychological distress? 1197 95

This study sought to investigate whether the effects of spa therapy are subject to seasonal variation as suggested by conventional spa therapy research. A total of 268 female (age 31-90 yr) and 119 male (age 35-85 yr) patients with noninflammatory chronic pain were studied. Patients stayed at an Austrian spa for 3 wk and received 2-4 treatments per day, including mudpacks, massages, and exercise therapy. In different groups of patients for 2 yr, pain (self-assessed by questionnaire and Likert scales) and associated variables (mood, fatigue) were measured at the beginning, end, and 6 wk after spa therapy. Data were analyzed by multivariate analysis of covariance controlling for possible group differences between seasons and cosinor analysis. The effect of spa therapy on pain was seasonally dependent; short-term decrease of pain was best between April and June and medium-term decrease of pain was best between October and November, with a second minor peak in fall and spring, respectively. The magnitude of the seasonal variation was greater for back (approximately 30%) than for joint (approximately 20%) pain. Positive mood also improved most between April and June. The observed semi-annual variations of pain do not correspond to the well-known annual change in many physiological and psychological variables. The results suggest that the effects of spa therapy and possibly other related treatments, such as physical and alternative therapies, are subject to seasonal variation.
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PMID:Seasonal variation in effect of spa therapy on chronic pain. 1202 37


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