Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0015672 (fatigue)
 51,768 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Dantrolene sodium or dantrolene1 is 1([5-(nitrophenyl)furfurylidend] amino) hydantoin sodium hydrate. It is indicated for use in chronic disorders characterised by skeletal muscle spasticity, such as spinal cord injury, stroke, cerebral palsy and multiple sclerosis. Dantrolene is believed to act directly on the contractile mechanism of skeletal muscle to decrease the force of contraction in the absence of any demonstrated effects on neural pathways, on the neuromuscular junction, or on the excitable properties of the muscle fibre membranes. Controlled trials have demonstrated that dantrolene is superior to placebo in adults or children with spasticity from various causes, as evidenced by clinical assessments of disability and daily activities, and by muscle and reflex responses to mechanical and electrical stimulation. It is somewhat less effective in patients with multiple sclerosis than in those with spasticity from other causes. There has been a general clinical impression in controlled trials that dantrolene caused less sedation than would have been expected from therapeutically comparable doses of diazepam. In 2 controlled trials, there was no significant difference between dantrolene and diazepam in terms of reductions in spasticity, clonus, and hyperreflexia, but side-effects such as drowsiness and inco-ordination occurred significantly more frequently on diazepam. Long-term studies have indicated continuing benefit for patients taking dantrolene, though the incidence of side-effects has often been high and there has been a suggestion of exacerbation of seizures in children with cerebral palsy. Dantrolene may be of value in the medical treatment of spasm of the external urethral sphincter due to neurological and non-neurological disease, and animal studies suggest a potential use in the management of malignant hyperpyrexia. Chemical evidence of liver dysfunction may occur in 0.7 to 1% of patients on long-term treatment with dantrolene, with symptomatic hepatitis in 0.35 to 0.5% and fatal hepatitis in 0.1 to 0.2%. The drug commonly causes transient drowsiness, dizziness, weakness, general malaise, fatigue and diarrhoea at the start of therapy. Muscle weakness may be the principal limiting side-effect in ambulant patients, particularly in those with multiple sclerosis, and therapy could be hazardous in patients with pre-existing bulbar or respiratory weakness. The dosage of dantrolene has been fixed in most controlled trials, though long-term studies have indicated the need for individualisation of dosage. The initial dose is usually 25mg once daily, increasing to 25mg two, three or four times daily, and then by increments of 25mg up to as high as 100mg two, three or four times daily. The lowest dose compatible with optimal response is recommended.
 ...
PMID:Dantrolene sodium: a review of its pharmacological properties and therapeutic efficacy in spasticity. 31 89

Complex motor habit (swimming in breast stroke style) revealed dissociation of the inner (electromyography) and ambient (chronogram of swimming) structure in conditions of emotional tension and fatigue. Some emotional states, however, induced consolidation of the habit due to the range of sportsmen and their psychological readiness for competition. The variety of emotional states seems to induce a variety of effects on the inner and ambient structures of the formed motor habit.
 ...
PMID:[Dissociation and consolidation of a motor habit in different emotional states]. 52 Jun 18

Fifteen Marine recruits with acute heat stroke were examined for (1) predisposing factors, (2) blood coagulation disturbances, (3) renal function abnormalities, and (4) blood composition alterations. Epidemiologic data identified the following risk factors; previous residence in a temperate climate, first phase of training, fatigue, and strenuous exercise in hot, humid conditions. Results of blood coagulation studies disclosed an increase in prothrombin and partial thromboplastin times, with a decrease in platelet count, probably indicating a transient, low-grade consumptive process. Blood urea nitrogen and creatinine levels and creatinine clearance were normal. Only mild elevations of SGOT, SGPT, and lactic dehydrogenase levels were noted, and in combination with clinical observations, they argued against significant muscle damage. No deaths or instances of renal failure occurred.
 ...
PMID:Acute heat stroke. Epidemiologic, biochemical, renal, and coagulation studies. 124 74

A total of 1,431 patients (mean age 63.4 +/- 14.1) with pacemakers (96.2% VVI) primoimplanted between 1967 and 1985 were followed for a mean duration of 78.2 +/- 40 pacing months, with 0.6% loss to follow-up. Cumulative survival for 1, 3, and 10 years was 0.9427, 0.9136, and 0.7536, respectively. There was no significant difference in survival between atrioventricular block (AVB) and sick sinus syndrome (SSS) patients. In addition to age and gender, factors existent prior to implantation that independently affected prognosis included manifest coronary heart disease (CHD), congenital/acquired heart lesions, heart failure, noncardiac internal disease, syncope, and generalized fatigue. After implantation, the most important factor was generalized fatigue, then age, stroke, myocardial infarct (MI), gender (male), heart failure, and syncope. Patients with no underlying disease showed an extremely high cumulative survival (0.9173 at 10 years). Compared to the general population of Yugoslavia, the pacemaker patients showed a similar yearly mortality rate until 1981. After that, elderly males (70+) had a significantly lower yearly mortality than the matched population. Thus, in this large series of pacemaker patients followed into the most recent period with an extremely low loss to follow-up, short- and long-term survival was very high. Pacemaker patients of any age who are otherwise in good health have an excellent prognosis.
 ...
PMID:Survival in 1,431 pacemaker patients: prognostic factors and comparison with the general population. 137 12

Ingestion of approximately 30-60 g of carbohydrate during each hour of exercise will generally be sufficient to maintain blood glucose oxidation late in exercise and delay fatigue. Since the average rates of gastric emptying and intestinal absorption exceed 1,250 ml.h-1 for water and solutions containing up to 8% carbohydrate, exercising people can be supplemented with both carbohydrate and fluids at relatively high rates. When cyclists exercise at competitive intensities for 2 h in the heat with a sweat rate of 1,400 ml.h-1, it is clear that the closer that fluid consumption matches sweating rate (at least up to 80% of sweating rate), the better. Increasing dehydration, due to inadequate fluid consumption, directly impairs stroke volume, cardiac output, and skin blood flow, which results in larger increases in body core temperature, heart rate, and ratings of the difficulty of exercise. This same phenomenon probably also applies to running, which argues against the notion that a certain amount of dehydration (i.e., up to 3%) is permissible and without major cardiovascular consequences. However, runners generally drink only 500 ml.h-1 of fluid and thus allow themselves to dehydrate at rates of 500-1,000 ml.h-1. The performance question boils down to "Will the time lost as a result of drinking larger volumes be compensated by the physiological benefits drinking produces and the faster running pace that might be achieved during the last half of the race?" However, if the goal is safety, which means minimizing hyperthermia, there is no question that the closer that the rate of drinking can match the rate of dehydration, the better.
 ...
PMID:Benefits of fluid replacement with carbohydrate during exercise. 140 5

Output power and metabolic input power values were determined for unconditioned canine latissimus dorsi (two), gastrocnemius (seven), and triceps (three) muscles contracting linearly to cause compression of a doubly valved pouch in a hydraulic model of the circulation. The motor nerves to the muscles were stimulated tetanically with 450 msec trains of 0.1 msec pulses having a frequency of 50/sec. The muscles were contracted 10, 20, 30, and 40 times per minute and pouch output in milliliters per minute was measured directly for each muscle at each contraction (train) rate. The output power in milliwatts was determined by two methods: (1) by using the pouch output and the pressure rise imparted to the stroke volume (average power) and (2) by using the pressure-volume loop. Metabolic input power in milliwatts was determined from the oxygen consumption in milliliters per minute of the working muscle. It was found that as the pouch output was increased, the pouch output power and the metabolic input power both increased. The average power output was slightly less than that computed from the pressure-volume loop. The mean output power values, when pumping at L liters per minute, were 0.62 L (average) and 0.75 L mW/gm (pressure-volume loop) for the latissimus dorsi muscles; 0.83 L (average) and 1.16 L mW/gm (pressure-volume loop) for the gastrocnemius muscles; and 0.55 L (average) and 0.66 L mW/gm (pressure-volume loop) for the triceps muscles. The percent efficiency of energy conversion ranged from 9.2% to 17.8% for the latissimus dorsi muscles, from 5.1% to 19.5% for the gastrocnemius muscles, and from 10.5% to 27.3% for the triceps muscles. However, it should not be concluded that one muscle type is better than another on the basis of percent efficiency because efficiency does not take endurance into account. An important observation in this study relates to the large output obtained with the three linearly contracting muscle types. All were capable of pumping in excess of 1.5 L/min. A second observation relates to the absence of fatigue, although determination of endurance was not an objective in these studies.
 ...
PMID:Output power and metabolic input power of skeletal muscle contracting linearly to compress a pouch in a mock circulatory system. 143 27

If the failing left ventricle could be given an effective push, other approaches to the treatment of heart failure would not be needed. We have inotropes only for short-term parenteral use. We have no safe inotrope for chronic oral use. The effect of digitalis is only feeble and the phosphodiesterase inhibitors seem to increase mortality from sudden death. Diuretics are dramatic for acute pulmonary oedema and the mainstay for chronic fluid retention but do not improve the pump and by reducing blood volume stimulate the renin angiotensin system to vasoconstriction, further fluid retention and hypokalaemia. Nitrates drop pre-load without reducing blood volume but tolerance is a problem and stroke volume does not increase. Reduction of afterload helps the failing ventricle to empty, the pull and output increases. The angiotensin converting enzyme inhibitors (ACEI) are now the cornerstone of heart failure treatment, reducing mortality in severe heart failure (CONSENSUS) and superior to standard vasodilator therapy (V-HeFT-2) at improving the survival of patients with mild to moderate heart failure. ACEI can reduce the incidence of ventricular ectopy and probably do this through improving left ventricular function, from decreasing sympathetic tone, reducing myocardial oxygen demand or increasing serum potassium but ACEI did not diminish the incidence of sudden death in the SOLVD trial despite reducing mortality. Disappointingly little improvement in exercise tolerance and persistence of chronic fatigue in heart failure concentrated attention on the periphery.(ABSTRACT TRUNCATED AT 250 WORDS)
 ...
PMID:The push, the pull and the periphery. 144 45

Nuclear medicine has a place in the study of brain trauma, brain tumours, stroke, dementia epilepsy and depression. The development of new tracers labelled with widely available radionuclides, such as technetium-99m (99Tc) and iodine-123, has played a key role here. Practical methodology can now be implemented in the routine setting. Additional applications are reviewed in the context of brain death, encephalitis, post-viral fatigue syndrome, Parkinson's disease and schizophrenia.
 ...
PMID:The role of nuclear medicine in neurology and psychiatry. 146 80

An eight-month prospective analysis of routinely collected hospital data with 24-week follow-up of mortality and morbidity was carried out at two district general hospitals in Somerset Health District, to test the feasibility of collecting useful and valid outcome measures for two common hospital conditions, strokes and fractured hips. Data were collected on 163 consecutive admissions with a primary diagnosis of stroke (83 cases) or fractured hip (80 cases). At 24 weeks, 38 patients with stroke had died (mortality ratio 46 per cent, 95 per cent C.I. = 35.3-56.7 per cent) and 11 with fractured hip had died (mortality ratio 14 per cent, 95 per cent C.I. = 6.4-21.6 per cent). Seven patients (four with fractured hip and three with stroke) died after 24 weeks and before responding to the NHP questionnaire. One stroke patient could not be traced. Nottingham Health Profiles were received from 106 patients (41 with stroke and 65 with fractured hip). Both groups of patients had problems with physical mobility and lack of energy. Patients with fractured hips were more likely to complain of pain. It is concluded that the methods used to collect outcome measures in this study are widely applicable to other conditions, but the interpretation and comparability of the results require the collection of similar data elsewhere.
 ...
PMID:A methodology for collecting outcome measures for common hospital conditions. 148 63

Although the pathophysiology of exercise intolerance in patients with chronic heart failure (CHF) is not fully understood, it appears that the cardiac output response plays an important role in limiting exercise in this disorder. Although previous studies have demonstrated that peak VO2 is not related to left ventricular (LV) ejection fraction, studies have consistently identified peak exercise cardiac output as an important predictor of peak VO2. It is likely that a reduced cardiac output to work rate relationship in CHF causes hypoperfusion of both working skeletal muscle and visceral organs, which leads to early anaerobic metabolism and fatigue. Several factors may influence the cardiac output response in patients with severe systolic LV dysfunction, including heart rate, diastolic LV function, and the mitral regurgitation fraction. Although stroke volume increases through use of the Frank-Starling mechanism in many patients with severe systolic LV dysfunction, some patients with this disorder may not increase stroke volume during exercise due to diastolic LV dysfunction or pericardial constraint. The finding that this latter group has more severe exercise intolerance suggests that diastolic dysfunction may further decrease peak VO2 in this disorder. Variations in the mitral regurgitation fraction also have been found to have an important effect on exercise stroke volume in some patients with CHF. Therefore, the finding that LV ejection fraction at rest or during exercise is not related to peak VO2 in patients with systolic LV dysfunction does not necessarily indicate that central hemodynamics do not play a role in exercise intolerance. Rather, it is likely that variability in the LV ejection fraction with exercise, which does not take variable increases in LV end-diastolic volume or mitral regurgitation into account, plays only a modest role in determining the stroke volume and cardiac output response to exercise in patients with severe systolic dysfunction.
 ...
PMID:Central hemodynamic response to exercise in patients with chronic heart failure. 157 62


1 2 3 4 5 6 7 8 9 10 Next >>