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

Single physical load (forced run up to fatigue) changes the lactate dehydrogenase activity in the myocardium and skeletal muscles of rats. It is pronounced in a sharp rise of the activity 1 h after the action, in a decrease 6 h after and again in an increase a day later and a gradual fall on the third seventh days. An increase in the portion of isoenzymes typical of the anaerobic metabolism is peculiar to the myocardium and skeletal muscles, that finds its manifestation in both an increase in the lactic acid amount and the lactate/pyruvate coefficient. A regular rise in the LDH2 amount in all periods of the study and LDH5 in the early period after the action is peculiar to the myocardium and the increase in the LDH5 content is characteristic of the skeletal muscles.
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PMID:[Lactate dehydrogenase isoenzyme spectrum in the myocardium and skeletal muscles of animals under physical stress]. 42 38

The clinical and physiologic effects of bronchopulmonary lavage of both lungs at separate times in 14 patients with alveolar proteinosis proved by biopsy were followed for 2 to 96 months. Before lavage, all patients had moderate to severe dyspnea on exertion. Twelve had a nonproductive cough, and 2 had a productive cough; both were smokers. Nine had generalized fatigue, and 4 had weight loss. Twelve of 14 had fine inspiratory rales. All of the patients had abnormal chest roentgenograms, and 13 of 14 had an increased lactate dehydrogenase concentration. After lavage, all patients had loss of fatigue and improved exercise tolerance, with most returning to normal activity. Cough cleared in 12 of 14 and remained only in the cigarette smokers. Inspiratory rales cleared completely in most patients (11 of 12) and partially in one. The rales usually returned during exacerbations. Physiologic measurements that changed significantly after bilateral lavage included: vital capacity, total lung capacity, resting room air PO2, exercise PO2, PO2 while breathing 100 per cent O2, and DLCO. Because all measurements were made within 5 days of the second lavage, one must attribute the acute improvement to the removal of proteinaceous material from the alveoli. The long-term effects varied; some patients required annual or semiannual lavages, wherease others remained in remission after lavage for 36 to 96 months. Exacerbations were accompanied by increased dyspnea, reappearance of rales, and deterioration of the gas-exchange parameters noted previously. Repeat lavage reversed the clinical symptoms and physiologic abnormalities in patients who had recurrences.
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PMID:Physiologic effects of bronchopulmonary lavage in alveolar proteinosis. 69 76

The lactate concentration in different muscle fibre types was determined in biopsy specimens from human vastus lateralis muscle after 30 and 60 s of maximal dynamic leg exercise. In addition, muscle fibre type distribution, total lactate dehydrogenase (LDH) activity, and isozymes of LDH were determined. In accordance with previous studies (Thorstensson and Karlsson 1976, Nilsson et al. 1977) it was found that an increasing proportion of slow twitch (ST) fibres corresponded to better sustained muscle force. Lactate was found preferentially in fast twitch (FT) fibres after 30 s, but after 60 s this difference was abolished. Differences between the two main muscle fibre types in muscle lactate, total LDH activity, and M-LDH activity were correlated to muscle fatigue. It was concluded that lactate or associated pH changes primarily in FT fibres could be one factor responsible for the impaired muscle function.
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PMID:Muscle fatigue and its relation to lactate accumulation and LDH activity in man. 71 62

Rat hepatocytes were isolated by liver perfusion in the presence of collagenase and hyaluronidase and incubated in the absence or presence of oxygen. As a result of anoxia, there was a gradual increase in plasma membrane permeability, noted as an increase in succinate-stimulated oxygen uptake, a decrease in trypan blue exclusion frequency, a leakage of cytosolic lactate dehydrogenase activity and an increased proportion of swollen and disrupted cells. After anaerobic incubation for 30 minutes--but not for 60 minutes--there were signs of recovery from anoxic cell injury upon re-oxygenation. The changes in plasma membrane permeability properties in anoxia seemed to be preceded by a marked decrease in cellular ATP level; aerobic incubation of hepatocytes in the presence of an uncoupler of phosphorylation from respiration led to a similar decrease in cellular ATP concentration followed by similar disturbances in plasma membrane permeability properties. It is suggested that a distrubed plasma membrane function caused by a decreased energy level is of primary importance for the initiation of cell death in anoxia.
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PMID:Isolated rat hepatocytes as an experimental tool in the study of cell injury. Effect of anoxia. 100 75

The activity of aldolase, lactate dehydrogenase and its isoenzymes was studied in various areas of the albino rat brain in stressed state connected with insomnia and fatigue. The activity of the mentioned enzymes in the brain various areas is established to change differently and depend on the stress agent. So, under insomnia the activity of aldolase increases in the horn of Ammon and midbrain and that of lactate dehydrogenase--in the great hemispheres and cerebellum. Under conditions of fatigue the activity of aldolase does not change, that of lactate dehydrogenase lowers in the great hemispheres and stem. In fatigue the activity of isoenzyme LDG1 lowers and that of LDG4+5--increases in the great hemispheres, stem and cerebellum. The activity of these isoenzymes is unchanged with insomnia.
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PMID:[Change in the activity of glycolytic enzymes in different areas of the albino rat brain in dependence on the stress agent]. 123 39

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.
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PMID:Acute heat stroke. Epidemiologic, biochemical, renal, and coagulation studies. 124 74

The latissimus dorsi (LD) muscle is considered suitable to assist ventricular mechanical function in either cardiomyoplasty or extra-aortic-assist devices. Such application requires that this mixed-type skeletal muscle be transformed into a fatigue-resistant muscle, the adaptation of which can be elicited by chronic stimulation. In this study the LD muscles of dog and goat were subjected in situ to 12 wk of continuous electrical stimulation through intramuscular electrodes, and their myofibrillar and metabolic adaptations were compared. A gradual increase in the contraction rate of the muscle (in 10 wk from 30 to 80 contractions/min) caused the proportion of immunohistochemically identified type I fibers to increase in dog muscle from 30 to 74% and in goat muscle from 21 to 99%. Correspondingly, the anaerobic-glycolytic activity (fructose-6-phosphate kinase and lactate dehydrogenase activities) decreased by approximately 75% in both dog and goat muscles, whereas the oxidative capacity (fatty acid oxidation and citrate synthase activity) increased two- to threefold in goat LD muscle but remained unaltered in dog LD muscle. Muscular contents of high-energy phosphates and endogenous substrates were maintained, but the L-carnitine content decreased by 43% in both dog and goat. Our data further indicate that, for the monitoring of the metabolic adaptation of skeletal muscle, the ratio of activities of the oxidative and anaerobic-glycolytic pathways (e.g., citrate synthase to fructose-6-phosphate kinase activities) is a useful parameter in both dog and goat.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Differences in metabolic response of dog and goat latissimus dorsi muscle to chronic stimulation. 140 41

Transformation of the latissimus dorsi (LD) muscle from a fast-twitch, fatigue-prone to a fatigue-resistant ("heart-like") muscle, necessary to allow its application in cardiac assist devices, can be induced by chronic electrical stimulation. In adult dogs we studied the nature and time course of myofibrillar and metabolic adaptations in the LD muscle when exposed in situ to 24 weeks of continuous electrical stimulation. In addition, the metabolic properties of the stimulated muscle were compared with those of canine cardiac muscle. The proportion of immunohistochemically identified type I fibres increased on stimulation from 28% to 80%, while that of type II fibres decreased from 69% to 16%. Fibres of intermediate type (IIC and IC) appeared transiently; the highest levels were found between 4 and 8 weeks of stimulation. The activities of fructose-6-phosphate kinase and lactate dehydrogenase (LDH), which before stimulation were similar to those in heart, decreased to 18% and 34% of their initial values respectively. However, the LDH isozyme pattern changed towards that typical for cardiac muscle. These changes indicate a markedly decreased flux capacity through the glycolytic pathway which, however, is directed more towards the oxidative conversion of substrates. The mitochondrial capacity (maximal palmitate oxidation and pyruvate dehydrogenase complex activities) of the muscle did not change and remained at a level less than half of that of cardiac ventricular muscle. Contents of adenine nucleotides and endogenous substrates were maintained during stimulation. No further changes in the observed adaptations occurred after week 12 of stimulation.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Adaptation of energy metabolism of canine latissimus dorsi muscle in response to chronic electrical stimulation. 155 54

This study has measured the pattern of elevated serum enzyme activity (ESEA) during extended daily training in a dose-response manner and compared ESEA to the pattern of accumulated fitness and fatigue predicted from a mathematical model previously described. Blood samples were taken regularly during the study from each subject and the activity of lactate dehydrogenase (LDH), creatine kinase (CK), and aspartate aminotransferase (AST) in the serum was measured. Although no single physiological/biochemical correlate of the hypothesized fatigue compartment of performance is firmly identified it is significant that the pattern of variation of model fatigue and ESEA throughout training were similar although slightly out of phase. With continued hard training, model fatigue began to plateau and concomitantly ESEA declined exponentially from its initial high value in early training. During relative rest throughout a tapering period following training both ESEA and fatigue reverted quickly towards baseline and follow the similar but earlier time course in blood of a degradative membrane enzyme phospholipase A2 observed in clinical studies.
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PMID:Dose/response effects of exercise modeled from training: physical and biochemical measures. 164 35

A study was made of the role of prolactin (PRL) in the regulation of thyroid function in intact animals and in those exposed to stress (swimming was used as physical exercise). A single daily dose of 125 micrograms of PRL per 100 g of body mass was injected subcutaneously in 0.5 ml of saline solution during a week to male rats (control: intact rats; injection of 0.5 ml of saline solution subcutaneously). Redox enzymes; succinate dehydrogenase, lactate dehydrogenase, glucose-6-phosphate dehydrogenase, NAD.H2 and NADP.H2, ATPase and monoamine oxidase, total protein, RNA and glycogen in glandular cells were investigated histochemically 24 h after the last injection of PRL or saline, 30 min., 1, 2, 3, 5 and 7 hours after swimming or right after complete fatigue (in the presence of experimental hyperprolactinemia). A conclusion has been made that one of the most important mechanisms of the adaptive effect of PRL is its ability to suppress thyroid function, thus decreasing the metabolism level, which results in reduction of oxygen consumption and improves body tolerance to stress.
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PMID:[Metabolism of thyroid gland cells as affected by prolactin and emotional-physical stress]. 178 Feb 95


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