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

The mechanical effects of ischemic contracture may be important in the development of irreversible cellular damage as it increases mechanical stress on sarcolemmal membranes and restricts endocardial perfusion. To assess the relative importance of these mechanical effects compared with decreased energy supply in the development of irreversible injury, the effects of inhibiting ischemic contracture with 2,3-butanedione monoxime (BDM), an agent that disrupts excitation-contraction coupling, were delineated in isovolumically contracting isolated rabbit hearts. Administration of 20 mmol/L BDM in 12 hearts subjected to 60 minutes of low-flow ischemia prevented ischemic contracture (left ventricular end-diastolic pressure [LVEDP], 12 +/- 3 compared with 48 +/- 14 mm Hg in 20 control hearts; P < .001), reduced membrane damage (creatine kinase [CK] release, -54% compared with control hearts; P < .05), and enhanced functional recovery during reperfusion (left ventricular developed pressure [LVDP], 86 +/- 10% of baseline compared with 56 +/- 23% in control hearts; P < .01). These observations were not related to increased intracavitary pressure and its effects on flow distribution, since venting the left ventricle in additional hearts did not result in improved function during reperfusion. Although it would be tempting to conclude that BDM protected ischemic myocardium by preventing ischemic contracture, administration of BDM was also associated with reduced depletion of ATP during ischemia, perhaps related to diminished energy demand. To distinguish between the relative importance of inhibiting contracture from provision of adequate energy, the period of ischemia was extended to 120 minutes. BDM still prevented ischemic contracture (LVEDP, 10 +/- 6 mm Hg) and preserved ATP stores, but it did not prevent membrane damage (CK release, 483 +/- 254 U/g dry weight) or contractile failure during reperfusion (LVDP, 68 +/- 7% of baseline). In contrast, increasing the rate of anaerobic glycolysis during ischemia by doubling glucose and insulin in the presence of BDM markedly decreased membrane damage (CK release, 114 +/- 72 U/g dry weight; P < .05) and contractile failure during reperfusion (LVDP, 88 +/- 7% recovery of baseline; P < .01). These results suggest that insufficient energy production is primarily responsible for myocardial ischemic damage, whereas mechanical effects of ischemic contracture appear to play only a minor role.
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PMID:The relative importance of myocardial energy metabolism compared with ischemic contracture in the determination of ischemic injury in isolated perfused rabbit hearts. 815 29

Functional electrical stimulation (FES) of paralyzed muscles holds promise as a strategy to assist patients in executing functional movements after spinal cord injuries. Muscle atrophy is one of the major problems that must be addressed for this approach to be successful. Loss of muscle mass may occur as a result of lesions to motoneurons in either the spinal cord or the central command pathway, or a combination of the two. For injuries to spinal motoneurons, muscle fibers undergo denervation atrophy. Damage to the central command pathway, on the other hand, results in disuse atrophy. In association with atrophy, the low contractile forces and inability of the muscles to sustain contractions are of direct therapeutic concern. In this review, methods aimed at recovery of function of paralyzed limbs by reducing susceptibility to fatigue and atrophy of paralyzed muscles are discussed. One is related to promoting nerve sprouting in partially denervated muscles to reinnervate muscle fibers and reverse denervation atrophy. The other regards training of paralyzed muscles to increase strength (muscle force) and endurance (fatigue resistance) by means of FES. Most training regimens with low-frequency FES increase muscle endurance. Efforts to design optimal regimens for increasing both muscle strength and endurance must involve consideration of several factors that are still controversial. These factors, which include muscle properties (such as fiber type composition and physiological type) and conditions imposed on the muscle (such as loading) during contractions elicited by FES, are discussed in detail.
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PMID:Muscle atrophy and procedures for training after spinal cord injury. 826 28

The existing relationship linking thermal and sport medicine has developed with time. This is shown by the established beneficial effects of thermal treatments (mineral waters, mud baths, balneotherapy, aerosol applications) in a wide range of sport and non-sport related injuries. The muscle fatigue syndrome is a condition particularly worrisome for sports practising individuals. This condition impairs the cardiovascular system, as well as hematologic, renal and gastrointestinal functions, acting via biochemical and metabolic modifications of the organism, which have effects also on the psyche of the subject. The treatment of this syndrome includes the use of specific mineral waters, which underscores that the correct hydration of the organisms is a precondition to achieve high performance levels. Traumas involving muscles and skeletal segments, and precocious arthrosis occur with higher frequency in sportsmen after continuous and intense stresses. Within the scope of rheumatology, mud-baths and balneotherapy have curative and rehabilitative potentials leading to a reduction, and often a disappearance, of pain with a faster recovery of the locomotory system. The gastrointestinal system is a target of psychic as well as physical stresses displaying symptoms or diseases which may be favourably addressed with the aid of mineral waters. This treatment has proved effective in secretory and motility dysfunctions of the biliary tree allowing a rapid functional recovery. Mineral water treatments are successfully employed in the treatment of urologic disturbance and ORL and dermatological pathologies, where local applications such as mud baths, balneotherapy, showers and aerosols, play a critical role.
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PMID:[Crenotherapy in sports medicine: the state of the art]. 929 24

Despite extensive information about long-term recovery from major joint arthroplasty, little attention has been given to the measurement of functional recovery in the immediate postoperative period. Therefore assumptions about the importance of physical therapy during this period remain untested. We devised a way of recording functional recovery before discharge, based primarily on the achievement of objective milestones. This was incorporated into routine physiotherapy practice and applied to sequential patients undergoing elective hip (n = 163) or knee (n = 66) replacement. Six months later, we followed up 160 patients, of whom 145 completed questionnaires to assess subjective physical and emotional state and functional recovery. The method was sensitive to known influences on pace of recovery, including type of arthroplasty (hip vs knee) and surgeons' differing requirements for mobilization. In addition, we were able to confirm and quantify sources of variation in functional recovery which previously were suspected but unconfirmed: in particular, the timing of early mobilization. Outcome at 6 months was unrelated to objective functional recovery in hospital, although fatigue and wellbeing at this time were predicted by physiotherapists' subjective assessment of patients' motivation before discharge. The findings can be used to inform patients and as a source of comparison data for the assessment of functional recovery in other centres. More importantly, the procedure reported may be applied to quantify functional recovery in routine practice and thereby expose variability in recovery to scientific scrutiny.
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PMID:The systematic assessment of short-term functional recovery after major joint arthroplasty. 1048 25

The results of neuromuscular reconstructions of the paralyzed face are difficult to assess. Very sophisticated methods are necessary to measure the motor deficits of facial paralysis or the functional recovery in the face. The aim of this development was a relatively simple system for data acquisition, which is easy to handle and which makes it relatively cheap to delegate data acquisition to centers all over the world, which will not be able to derive a data analysis on their own, but will send their data to a center with specialized equipment. A complex mirror system was developed to get three different views of the face at the same time on the video screen. At each investigation, a digital video is taken from a calibration grid and from standardized facial movements of the patient. Secondary analysis of the digital videofilm is made possible at any time later on by the support of a computer program, which calculates distances and movements three-dimensionally from the frontal image and the right and left mirror images. Pathologies of the mimic movements can be identified as well as improvements after surgical procedures by this system. The significant advantage is the possibility to watch the same movement on the video which is under study and to apply any kind of study later on. Taking the video needs only a few minutes, and fatigue of the patient's mimic system is prevented. Measurements usually at the endpoints of the movements give excellent information on the quantity of the movement or the degree of the facial palsy, whereas the video itself is very informative regarding the quality of the smile. Specific computer software was developed for standardized three-dimensional analysis of the video-documented facial movements and for data presentation. There are options like two-dimensional graphs of single moving points in the face or three-dimensional graphs of the movements of all measured points at the same time during a standardized facial movement. By a comparison of the right- and left-sided alterations of specific distances between two points during the facial movements, the degree of normal symmetry or pathologic asymmetry is quantified. This system is more suitable for detailed scientific multicenter studies than any other system previously established. A very sensitive instrument for exact evaluation of mimic function is now available.
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PMID:Three-dimensional video analysis of facial movements: a new method to assess the quantity and quality of the smile. 1114 65

We examined whether the emotional response to hip arthroplasty predicted functional recovery after controlling for preoperative function and surgical trauma. Mood and fatigue were measured in 102 consecutive patients preoperatively and 3 days postoperatively. Time of achievement of functional milestones indicated recovery in hospital, and functional status was measured preoperatively and 1 and 6 months postoperatively. Circulating C-reactive protein and interleukin-6 levels indicated trauma. Recovery in hospital was slower in patients with greater trauma. Recovery at follow-up was slower in patients with poorer preoperative function and with greater anxiety and fatigue, but the apparent influence of anxiety was explained by its association with preoperative function and fatigue. Whereas short-term recovery is predicted by surgical trauma, long-term recovery is predicted by preexisting function and the emotional response to surgery. However, the influence of the emotional response is small and the important aspect of emotion is fatigue rather than anxiety.
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PMID:Influence of the emotional response to surgery on functional recovery during 6 months after hip arthroplasty. 1170 61

This article reviews the scientific research needed to ensure the continued development, validation, and operational transition of biomathematical models of fatigue and performance. These models originated from the need to ascertain the formal underlying relationships among sleep and circadian dynamics in the control of alertness and neurobehavioral performance capability. Priority should be given to research that further establishes their basic validity, including the accuracy of the core mathematical formulae and parameters that instantiate the interactions of sleep/wake and circadian processes. Since individuals can differ markedly and reliably in their responses to sleep loss and to countermeasures for it, models must incorporate estimates of these inter-individual differences, and research should identify predictors of them. To ensure models accurately predict recovery of function with sleep of varying durations, dose-response curves for recovery of performance as a function of prior sleep homeostatic load and the number of days of recovery are needed. It is also necessary to establish whether the accuracy of models is affected by using work/rest schedules as surrogates for sleep/wake inputs to models. Given the importance of light as both a circadian entraining agent and an alerting agent, research should determine the extent to which light input could incrementally improve model predictions of performance, especially in persons exposed to night work, jet lag, and prolonged work. Models seek to estimate behavioral capability and/or the relative risk of adverse events in a fatigued state. Research is needed on how best to scale and interpret metrics of behavioral capability, and incorporate factors that amplify or diminish the relationship between model predictions of performance and risk outcomes.
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PMID:Critical research issues in development of biomathematical models of fatigue and performance. 1501 83

The purpose of this study was to examine the psychosocial and disease-specific factors that influence functional recovery in older adults newly diagnosed with cancer. Multivariate logistic regression models were estimated using panel data from a sample of community-residing adults older than 65 years surgically treated for lung, prostate, breast, or colorectal cancer (N = 172). Data were obtained between 1993 and 1997 during interviews 4 to 6 weeks after cancer surgery for Wave 1 and 14 to 16 weeks after hospital discharge for Wave 2. The outcome measure, functional recovery, was determined by comparing the physical function and physical role subscales of Medical Outcomes Study (MOS) SF-36 over time. Findings showed that prostatectomy patients were more likely to recover by Wave 2 when compared to individuals with lung, colon, or breast resections. Comorbidities and symptom severity were each significantly associated with a decreased probability of recovery. Pain and fatigue were the most common and most severe symptoms reported, regardless of primary site. Psychological well-being was a significant factor influencing functional recovery when age, comorbidities, site of disease, and symptom severity were controlled. The results clearly point to the need for psychological support following cancer surgery.
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PMID:Determinants of functional recovery in older adults surgically treated for cancer. 1510 47

Muscle intolerance to exercise may result from different processes. Diagnosis involves confirming first the source of pain, then potential pathological myalgia. Delayed-onset muscle soreness (DOMS), commonly referred as tiredness, occurs frequently in sport. DOMS usually develops 12-48 h after intensive and/or unusual eccentric muscle action. Symptoms usually involve the quadriceps muscle group but may also affect the hamstring and triceps surae groups. The muscles are sensitive to palpation, contraction and passive stretch. Acidosis, muscle spasm and microlesions in both connective and muscle tissues may explain the symptoms. However, inflammation appears to be the most common explanation. Interestingly, there is strong evidence that the progression of the exercise-induced muscle injury proceeds no further in the absence of inflammation. Even though unpleasant, DOMS should not be considered as an indicator of muscle damage but, rather, a sign of the regenerative process, which is well known to contribute to the increased muscle mass. DOMS can be associated with decreased proprioception and range of motion, as well as maximal force and activation. DOMS disappears 2-10 days before complete functional recovery. This painless period is ripe for additional joint injuries. Similarly, if some treatments are well known to attenuate DOMS, none has been demonstrated to accelerate either structural or functional recovery. In terms of the role of the inflammatory process, these treatments might even delay overall recovery.
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PMID:[Delayed post effort muscle soreness]. 1529 19

We have analysed the rate and ultimate extent of muscle functional recovery after snake venom-induced myotoxicity, as well as the relationships between functional, biochemical and structural indices of recovery. We also compared the effects of various injuries leading to muscle necrosis, loss of innervation/vasculature and/or precursors of muscle cells (pmc). We found that several parameters of rat soleus muscle such as maximal isometric force, slow myosin heavy chain, and citrate synthase, were fully and rapidly restored within 6 weeks after treatment with snake Notechis scutatus venom (im, 2 microg/muscle). In contrast, some muscle contractile properties (degree of tetanic fusion, fatigue resistance...) were not fully recovered even by 12 weeks after venom treatment. However, when compared to other injuries, recovery 3 weeks after venom treatment, was better than that observed after severing the terminal nerve and accompanying vessels and after cryodamage known to kill pmc. In conclusion, our studies demonstrate that-contrary to what is commonly believed -- muscle treated by myotoxic agent does not recover rapidly and fully. However, the degree or rate of muscle recovery after snake venom treatment was much better when compared to other types of injury. In addition, histological and biochemical parameters cannot be used as such to easily predict functional recovery following injury.
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PMID:Functional, cellular and molecular aspects of skeletal muscle recovery after injury induced by snake venom from Notechis scutatus scutatus. 1580 29


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