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

In the third week after acute myocardial infarction, mean 18 days, exercise tests have been performed in 209 patients prior to discharge from the Coronary Care Unit. The exercise was done on a bicycle ergometer with electrically controlled braking, starting at the load 300 kpm/min (equal to 50 W), increasing with 300 kpm/min every 6th min, aiming at a maximal symptom-limited performance. ECG, in 3 extremity leads and 3 precordial leads, and heart rate (HR) were continuously recorded, and blood pressure (BP) was measured every minute. The most common cause for discontinuing exercise was fatigue (in 58%). Anginal pain or dyspnoea was the cause in 23.8%. Only in 9.1% was the exercise interrupted by the investigator because of rhythm disturbances or pronounced ST-T changes. Maximal work varied from 1 min exercise at 300 kpm/min to 6 min at 900 kpm/min (150 W); 18% of all patients were able to work for 6 min at 600 kpm/min (100 W). HR increased on an average from 80 beats/min at rest to 129 beats/min at maximal work load. Systolic blood pressure (SBP) increased on an average from 126 to 170 mmHg. The maximal values reached during exercise were HR 170/min, and SBP 270 mmHg. The product HR X SPB increased a little more than two-fold on an average. ST-T changes indicating myocardial ischaemia during exercise were observed in 70%. During exercise ventricular ectopic beats occurred in 42%. All rhythm disturbances provoked by exercise disappeared spontaneously shortly after work. Persistent ECG changes, reinfarction or other serious complications were not observed in connection with the exercise test. It is concluded that an exercise test under controlled circumstances is safe in patients of all ages in the third week after myocardial infarction. It is an objective measure of physical work capacity and described the reaction to physical activity. It gives a basis for advising return to normal life and is of great psychological importance to the patient.
Acta Med Scand 1975 Dec
PMID:Routine exercise ECG three weeks after acute myocardial infarction. 121 Dec 15

3 cases of cyclical convergent strabismus (48 hour rhythm) were investigated. In contrast to intermittant strabismus, cyclical strabismus is not fatigue dependant. An alteration in the rhythm of the cyclical esotropia was produced by wearing prisms, red glasses or occlusion for several days. This observation indicates that centrally inaugurated rhythm processes can be altered by peripheral sensory influcences. In the case of our third patient, who was not operated upon, there was a cyclical strabismus which persisted from the age of 4 to 19 years, before changing to a constant convergent strabismus. The other two patients, following strabismus surgery, had a small angle esophoria with good fusion and stereopsis.
Klin Monbl Augenheilkd 1975 Dec
PMID:[Alternate day squint (author's transl)]. 122 20

The syndrome of chronic fatigue, feverishness, diffuse pains, and other constitutional complaints, often precipitated by an acute infectious illness and aggravated by physical and emotional stressors, has a lengthy history in the medical literature. The Centers for Disease Control (CDC) recently formulated a case definition, renaming the illness "chronic fatigue syndrome." Nevertheless, there remain few biological data that can validate the existence of this syndrome as distinct from a wide variety of other, largely psychiatric disorders, and little understanding of its pathogenesis. In the present study, basal plasma and cerebrospinal fluid levels of the monoamine metabolites, 3-methoxy-4-hydroxyphenylglycol (MHPG), 5-hydroxyindoleacetic acid (5-HIAA), and homovanillic acid (HVA) were determined in 19 patients meeting CDC research case criteria for chronic fatigue syndrome and in 17 normal individuals. Patients with chronic fatigue syndrome showed a significant reduction in basal plasma levels of MHPG and a significant increase in basal plasma levels of 5-HIAA. Although the functional significance of these findings has not been definitively elucidated, they are compatible with the clinical presentation of a syndrome associated with chronic lethargy and fatigue, and with evidence of persistent immune stimulation, and lend support to the idea that chronic fatigue syndrome represents a clinical entity with potential biological specificity.
Biol Psychiatry 1992 Dec 15
PMID:Plasma and cerebrospinal fluid monoamine metabolism in patients with chronic fatigue syndrome: preliminary findings. 128 70

The electromyogram (EMG) is often used to study human muscle fatigue, but the changes in the electromyographic signals during muscle contraction are not well understood in relation to muscle metabolism. The 31P NMR spectroscopy is a semi-quantitative non-invasive method for studying the metabolic changes in human muscle. The aim of this study was to develop a method by which EMG and NMR spectroscopy measurements could be performed simultaneously. All measurements were performed in a whole body 1.5 Tesla NMR scanner. A calf muscle ergometer, designed for use in a whole body NMR scanner, was used. The subject had the left foot strapped to the ergometer. The anterior tibial EMG was recorded by bipolar surface electrodes. A surface coil was strapped to the anterior tibial muscle next to the EMG electrodes. Simultaneous measurements of surface EMG and surface coil 31P NMR spectroscopy were performed in the scanner during an isometric submaximal voluntary contraction until exhaustion, in 6 normal volunteers. Concentrations of phosphocreatine (PCr), inorganic phosphate (P(i)) and pH were analysed together with root mean square (RMS) and median frequency of the EMG. The fatiguing contractions (endured 5-13 min) produced a rapid decline in PCr and pH accompanied by a rapid rise in P(i). The RMS was approximately constant until the normalized PCr concentration declined below 0.6-0.7 and the pH declined below 6.75-6.85; exceeding these metabolic limits was associated with a rapidly increasing RMS value (2-3 times the previous level by exhaustion). The median frequency declined linearly with time and was found to be highly linearly correlated with the pH value (r = 0.82).(ABSTRACT TRUNCATED AT 250 WORDS)
Electroencephalogr Clin Neurophysiol 1992 Dec
PMID:Simultaneous electromyography and 31P nuclear magnetic resonance spectroscopy--with application to muscle fatigue. 128 59

The contractile properties of a muscle depend on the activation history of its motor units. At the same time as fatigue seems to impair muscle excitation-contraction coupling, post-tetanic potentiation can augment force production. The effects of post-tetanic potentiation on the mechanical muscle properties of the intact human ankle extensor muscles were investigated by a 4 degree dorsiflexion of the ankle joint during a sustained contraction. The contraction was elicited by 10 Hz electrical stimulation of the tibial nerve. The changes in the contraction torque and in the intrinsic muscle stiffness of the ankle extensors before and after prolonged electrically elicited muscle activation were measured. From the onset of continuous synchronized 10 Hz stimulation to the attainment of maximal torque, the ankle joint torque increased by 47%. At matched background contraction, the prolonged electrically elicited contraction increased the intrinsic muscle stiffness by 49%. The first stretch after prolonged stimulation gave rise to a 17% yield in the background contraction and a 73% yield in the torque increment. The findings imply that with fatigue an increase in the intrinsic stiffness of the pre-stretched muscle might operate as a "safety factor" to compensate for a reduced reflex-induced stiffness, keeping the total muscle resistance at a high level in the active muscle.
Electroencephalogr Clin Neurophysiol 1992 Dec
PMID:Mechanical properties of human ankle extensors after muscle potentiation. 128 60

In a detailed study mechanical properties of tendons, muscles, nerves, blood-vessels and skin of just slaughtered pigs have been investigated in nearly stationary stress tests. Tensile tests have produced tensile strength, ultimate stress and their appropriate strains, Young's modulus and the work up to fatigue of samples. In hysteresis tests the deformation work has been determined as a function of numbers of stress cycles. The hysteresis decrease with the number of stress cycles and approaches asymptotically to cero. By preconditioning of tendons, nerves and blood-vessels to steady state significant differences of strain at tensile strength and of Young's modulus have been established. Moreover for nerves the tests have revealed significant deviations of tensile strength. Bruise tests have been carried out with muscle tissue. For the described setup the limit force can be specified, at which pathological changes appear. Subsequently conducted histological investigations have demonstrated this. In dynamical bruise tests there appeared no pathological changes in muscle tissue in spite of higher transmitted energy.
Biomed Tech (Berl) 1992 Dec
PMID:[Mechanical characteristics of biological soft tissue]. 128 44

Ten patients with chronic type B hepatitis were treated for four weeks with a rapidly tapered dose of oral prednisone (initial dose, 40 mg/d) followed by two weeks of no therapy followed by four weeks of oral acyclovir (600 mg/d). Liver biochemistry, HBsAg, HBeAg, DNA-polymerase and HBV-DNA levels in serum were determined prior to, during and for six months following therapy. The mean age +/- SD of the study population was 33 +/- 15 years (range 18-58). Nine of the patients were male. Four patients were Caucasian and six of Southeast Asian origin. Three patients were homosexual, all HIV antibody negative. The mean ALT level prior to treatment was 89 +/- 62 IU/L (range: 30-214). During the six month post-treatment follow-up period, 5/8 (63%) patients became DNA-P negative and 6/10 (60%) HBV-DNA negative. One responder reverted to DNA-P positive (final response, 50%) and another to HBV-DNA positive (final response, 50%) prior to completion of the study. Patients were more likely to become DNA-P or HBV-DNA negative if they had elevated pre-treatment ALT values and low levels of DNA-P and HBV-DNA. HBeAg became undetectable in 3/10 (30%) individuals, one of whom reverted to positive at the end of the follow-up period (final response, 20%). All patients remained HBsAg positive. Mild fatigue, which occurred in four individuals, was the most common side effect. The results of this study suggest that a controlled clinical trial of oral prednisone/acyclovir is warranted in the treatment of adults with chronic type B hepatitis.
Clin Invest Med 1992 Dec
PMID:A pilot study of steroid withdrawal followed by oral acyclovir in the treatment of chronic type B hepatitis. 128 32

Subjects viewed unambiguous versions of both stationary and rotating Necker cube illusions for varying durations prior to the presentation of the standard ambiguous figure. In each case, the subjects were more likely to report the ambiguous figure to be (1) in the same configuration as that of the preceding prime following brief preexposure periods and (2) in the opposite configuration from that of the preceding prime following long preexposure periods. In addition, the number of reversals of the figure during the test period was also strongly related to the duration of the preexposure period, with progressively fewer reversals reported following longer preexposure periods. The results are interpreted as revealing the concurrent roles of "set" effects in the brief preexposure conditions and neural fatigue effects in the long preexposure conditions. Furthermore, the ability of the proposed two-process model to integrate the myriad of empirical effects in the reversible-figure literature is emphasized.
Percept Psychophys 1992 Dec
PMID:Prime time: fatigue and set effects in the perception of reversible figures. 128 66

Interferon (IFN) related neurotoxicity includes somnolence and confusion, fatigue, lethargy, psychiatric symptoms, conceptual disorganization, neurological deficits, cortical blindness, coma and, rarely, death. The neurologic syndromes seem to be more common in elderly patients, following intramuscular or intravenous administration, at higher doses of frequent injections of IFN-alpha and in primary renal cell carcinoma. The duration of the treatment was not strongly related to neurotoxicity. Computed tomography findings were non-specific and included atrophy or periventricular lucencies. Electroencephalograph studies demonstrated a generalized increase in slow wave activity which returned to normal after cessation of treatment. Behavioral and mental changes in patients treated with IFN are warning signs, and indicate the need to withdraw treatment.
Anticancer Drugs 1992 Dec
PMID:Neurotoxicity of interferon-alpha. 128 26

Chronic heart failure is a common clinical condition with a high mortality and morbidity. Patients with the condition suffer from shortness of breath and fatigue on exercise. This article reviews the recent advances made in the understanding of the pathophysiology of chronic heart failure and explores further possible research options.
Eur Heart J 1992 Dec
PMID:The mechanisms underlying the increased ventilatory response to exercise in chronic stable heart failure. 128 2


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