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

Rat cardiac myocytes were isolated by heart perfusion in the presence of collagenase and incubated in the absence of presence of oxygen. As a result of anoxia, there was a gradual increase in plasma membrane permeability, noted as a decrease in trypan blue exclusion frequency, leakage of cytosolic lactate dehydrogenase and intracellular accumulation of the isotope compound 99Tcm-gluconate. The changes in plasma membrane permeability properties were preceded by a marked decrease in cellular ATP level and an increased proportion of contracted myocytes. The ability of the myocytes to resynthesize ATP and to recover from the anoxic injury upon reoxygenation decreased gradually with the length of initial anaerobic incubation during the first 25 min and disappeared after 30 min of anoxia, indicating that the anoxic injury to the isolated rat cardiac myocytes becomes irreversible after 25--30 min of anoxia. It is suggested that a decreased energy level is of primary importance for the initiation of cell injury in anoxia and that it is followed by cell contracture and subsequently by a disturbed plasma membrane function, cell swelling and death. This experimental model system of isolated viable rat cardiac myocytes is suitable for problems dealing with reversibility of myocytic injury.
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PMID:Isolated rat cardiac myocytes as an experimental tool in the study of anoxic cell injury. Effect of reoxygenation--a preliminary report. 720 17

A family with a complete deficiency of lactate dehydrogenase M-subunit was investigated. The propositus was an 18-year-old male who complained of exertional pigmenturia and easy fatigue. Marked discrepancy was observed in the ratio between creatine kinase and lactate dehydrogenase (CK/LDH). Electrophoretic analysis of serum LDH isoenzymes of the propositus demonstrated only one activity band of LDH H4. A complete lack of the LDH M-subunit was similarly demonstrated in erythrocytes, leukocytes and in the intermediate vastus muscle. LDH levels in the muscle specimen were markedly decreased in the patient, whereas CK and aspartate aminotransferase were almost the same as in a control subject. LDH isoenzymes of erythrocytes were analyzed in 5 siblings and in the parents. This demonstrated a complete lack of LDH M-subunit in 3 siblings. The ratio between H-subunit and M-subunit (H/M) in erythrocyte LDH suggested a partial absence of the M-subunit in two siblings and in the parents. An abortive increase of blood lactate and a marked increase in blood pyruvate were observed immediately after ischemic work of the forearm, accompanied by an increase in serum creatine kinase and myoglobinuria. The present case represents a newly described form of genetically determined myopathy.
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PMID:Hereditary deficiency of lactate dehydrogenase M-subunit. 744 46

An autopsy case of a 42 year old man with the anerythremic form of acute erythremic myelosis (Di Guglielmo's syndrome) is reported. The patient was admitted because of a 1 month history of fatigue and fever. Physical examination showed hepatosplenomegaly. Laboratory data showed leukopenia, mild normocytic anemia, and high levels of serum lactate dehydrogenase and vitamin B12. Bone marrow aspirate revealed an elevated number of erythroblasts, with dyserythropoiesis (E/M = 3.7). After admission, thrombocytopenia progressed rapidly, but blast cells were not seen in the peripheral blood throughout the clinical course. On the 56th hospital day, the patient died of pneumonia. At autopsy, the spleen weighed 550 g and the liver 1800 g. Histologically, the white and red pulps of the spleen and the portal region and sinusoid of the liver were diffusely infiltrated by blast cells that were positive for anti-hemoglobin (Hb) antibody on immunoperoxidase staining. The bone marrow, the lymph nodes, the adrenal glands, the pancreas, and the heart were also infiltrated by the blast cells. This was thus considered to be a rare case of the anerythremic form of acute erythremic myelosis (Di Guglielmo's syndrome), the findings showing that Hb immunoperoxidase staining is useful for the diagnosis of this condition.
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PMID:Anerythremic form of acute erythremic myelosis (Di Guglielmo's syndrome) causing hepatosplenomegaly due to the infiltration of hemoglobin-bearing blast cells: an autopsy case. 755 Oct 2

1. The initiation of exercise-induced muscle injury is thought to be the result of high tensile stresses produced in the muscle during eccentric contractions. Materials science theory suggests that high tensile stresses could initiate the injury during the first eccentric contraction (normal stress theory) or after multiple eccentric contractions (materials fatigue). It was the objective of this study to investigate the two possibilities. 2. Rat soleus muscles (n = 66; 11 protocols with 6 muscles per protocol) were isolated, placed in an oxygenated Krebs-Ringer buffer at 37 degrees C, and baseline measurements were made. The muscle then performed an injury protocol which consisted of between zero and ten eccentric contractions (muscle starting length = 0.90 soleus muscle length, L0; length change = 0.25 L0; velocity = 1.5 L0/s; peak force = 180% maximal isometric tetanic tension (P0); time between contractions = 4 min; total duration of the injury protocol = 40 min). At the end of the injury protocol, the muscle was incubated in buffer for 1 h; every 15 min, an isometric twitch and tetanus were performed and lactate dehydrogenase (LDH) release was measured. Total muscle [Ca2+] was measured at the end of the incubation. 3. Change-point regression analysis indicates that at 0 min into the incubation, declines in P0, maximal rate of tension development (+dP/dt), maximal rate of relaxation (-dP/dt), and muscle stiffness (dP/dx) became significantly greater after eight eccentric contractions (p < or = 0.05). No relation was found between the number of eccentric contractions performed and the LDH activity at 0 min into the incubation, although after 60 min of incubation, LDH activity in the buffer was linearly related to eccentric contraction number (p = 0.01). There was no relationship between total muscle [Ca2+] and eccentric contraction number. These findings support the materials fatigue hypothesis of exercise-induced muscle injury.
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PMID:Materials fatigue initiates eccentric contraction-induced injury in rat soleus muscle. 822 14

The viability of osteocytes can be demonstrated in sawn decalcified sections of bone by their lactate dehydrogenase activity. In the cancellous bone of the femoral head, the proportion of lacunae containing viable osteocytes decreased from 88 +/- 7% (mean +/- SD) at 10-29 years to 58 +/- 12% (P < 0.001) by 70-89 years. Viability in the second lumbar vertebra was 88 +/- 3% in subjects aged 25-90 years and did not decrease with age. Mean osteocyte viability in the femoral head of 21 hip fracture patients aged 72-94 years was 58 +/- 21%, similar to controls of a similar age, though there was greater variation and, in five patients, osteocyte viability was less than 25%. In hip fracture patients, microfracture callus incidence correlated positively with osteocyte viability, with little or no fracture callus observed if the bone viability was low. Ultimate compressive strength did not correlate with osteocyte viability. In the femoral head there is gradual, age-related reduction in osteocyte viability that can be more pronounced in hip fracture. Osteocyte death may affect bone quality by impairing repair of fatigue damage.
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PMID:Osteocyte death and hip fracture. 827 64

Antibiotic treatment tends sometimes to result in sensations of fatigue and decreased physical performance. The effects of antibiotics were therefore studied in 50 healthy, male trainees, aged 18-25 years, assigned in a random, double-blind fashion to one of the following treatments: tetracycline, ampicillin, trimethoprim/sulphamethoxazole, placebo I and placebo II. Duration of treatment was five times the half-life of each agent and the placebo was matched accordingly. Muscle enzyme activity (serum glutamine oxaloacetate transaminase, lactate dehydrogenase, creatine phosphokinase), maximal aerobic capacity (VO2max), muscle strength (MS), and rating of subjective sensation of fatigue were assessed prior to and upon conclusion of treatment. Compared to pretreatment values, plasma enzymes activity was elevated in all five groups (P < 0.005). No differences in VO2max or in MS were found among the subjects treated with either one of the antibiotics or those given a placebo. A significant difference in VO2max was found between the groups treated for 1 day (antibiotic and placebo) and the groups treated for 3 days (antibiotic and placebo) (P < 0.0001). The rating of subjective sensation was not affected by any of the agents. We concluded that in healthy individuals, a short-term antibiotic treatment had no deleterious effect on aerobic capacity or on muscle strength and was not associated with subjective side effects. The time interval between the two maximal tests could, however, have affected the aerobic capacity. Physiological disturbances associated with a sensation of fatigue following a longer period of antibiotics cannot be excluded.
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PMID:The relationship between short-term antibiotic treatments and fatigue in healthy individuals. 849 2

It is now well established that strenuous engagement in aerobic endurance sports may cause menstrual problems and hypoestrogenemia-related phenomena, such as osteoporosis. The present study was designed to assess whether the competitive practice of female judoists produces specific physiological changes in menstruation and bone and muscle metabolism. A test group of 17 white female judoists (mean VO2max, 50.9 +/- 2.8 mL/kg.min; mean percent body fat, 16.3 +/- 3.3%), a reference group of oarswomen, and a group of sedentary women participated in this study. Specific metabolic parameters were determined before and after a heavy 5-week pre-Olympic training period. With regard to anthropometrical characteristics, after a period of intensive training, female judoists significantly differed (P < 0.05) from their pretraining values for percent body fat (-2.2%) and number of oligomenorrheic individuals (+28.4%). Mean baseline posttraining luteal phase plasma levels of estrone (78 +/- 26 pmol/L), estradiol (85 +/- 70 pmol/L), LH (7.6 +/- 2.8 IU/L), and progesterone (13.4 +/- 3.1 nmol/L) were significantly lower than those in both reference groups, although pretraining values did not significantly differ from those in a group of oarswomen. Luteal phase posttraining urinary parameters of muscular catabolism (3-methylhistidine, 367 +/- 30 mmol/day) and collagen turnover (hydroxyproline, 678 +/- 14 mumol/L) were significantly higher than those in a group of oarswomen (3- methylhistidine, 183 +/- 18 mmol/day; hydroxyproline, 196 +/- 21 micrograms/mL). Total plasma spontaneous monocyte interleukin-1 activity, an experimental parameter for bone turnover and formation, was significantly higher (P < 0.05) in both female judoists (15.8 +/- 3.0% max) and oarswomen (7.1 +/- 1.8% max) than in sedentary women (5.2 +/- 2.2% max). These findings were accompanied by a subjective feeling of musculotendinous soreness and fatigue. Posttraining values for blood diagnostic enzymes, such as creatinine phosphokinase, glutamic oxalacetic transaminase, lactic dehydrogenase, and uric acid exceeded 2-5 times maximal normal laboratory reference values. We believe that these overtraining-like findings should be further examined to study the eventual causal relationship between hypoestrogenemia and rhabdomyelysis (myoglobinuria) and to fully understand the extent of these results and their importance to the female athlete's health.
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PMID:Hypoestrogenemia and rhabdomyelysis (myoglobinuria) in the female judoist: a new worrying phenomenon? 853 Jun 13

A 22-year-old man developed transient unconsciousness during running. He developed fever, nausea, vomiting, diarrhea and general fatigue. Next day, he was admitted to National Hospital Nayoro because of high serum CK level of 13,610U/l. Biochemical analyses revealed elevated serum myoglobin, increased CK-MM isozyme, aldolase and lactate dehydrogenase, increased serum osmolality, increased uric acid, and decreased serum potassium levels. Therefore, he was diagnosed as having rhabdomyolysis. In addition, serum CK-MB isozyme, cardiac myosin light chain I and troponin T were increased, suggesting the damage of cardiac muscle. Electrocardiogram showed elevated ST segment and inverted T on V2-4, which were not observed previously. He had no preceding infectious disease, drug ingestion or an underlying metabolic disorder. The rhabdomyolysis may be precipitated by the superimposition of dehydration and loss of potassium due to diarrhea and vomiting. The myocardial injury, probably produced by transient myocardial ischemia, should be paid attention in case of rhabdomyolysis.
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PMID:[A case of rhabdomyolysis complicated with myocardial injury]. 856 47

Two groups of mice were fed with either hedgehog hydnum powder or extract for sixty days. For the assay of fatigue, the activity of serum lactate dehydrogenase, the serum urea nitrogen content, blood lactic acid, hepatic and muscular glycogen, and the physical stamina of the mice were determined. The activity of serum lactate dehydrogenase and the hepatic and muscular glycogen content in the experimental mice were evidently higher than that in the control mice (P < 0.05 or P < 0.01). After exercise, the increase in blood lactic acid and serum urea nitrogen in the experimental mice was significantly lower than that in the control mice (P < 0.05 or P < 0.01), but the rate of elimination of blood lactic acid in the experimental mice was significantly higher than that in the control mice (P < 0.05). In the physical stamina swimming, the experimental mice drowned after a longer period of time than the control mice (P < 0.05). In conclusion hedgehog hydnum had a significant effect on raising physical stamina and delaying fatigue in mice.
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PMID:[Effect of hedgehog hydnum on the delay of fatigue in mice]. 875 99

Pharyngeal muscles play important roles in the maintenance of upper airway patency during sleep. The present study determined the extent of heterogeneity among pharyngeal muscles and the diaphragm in their metabolic profiles, and examined whether differences among muscles may account for previously described differences in their fatigue resistance. Cat and rat sternohyoid, geniohyoid, genioglossus (cat only) and diaphragm muscle were assayed for activities of the mitochondrial enzyme citrate synthase (CS), the glycolytic enzyme phosphofructokinase (PFK) and the cytosolic enzyme lactate dehydrogenase (LDH). CS activity varied among muscles in both species, being highest for genioglossus in cat and highest for diaphragm in rat. PFK activity was highest for genioglossus in cat, but did not differ among muscles in rat. LDH activity was lower for the genioglossus than the sternohyoid and diaphragm in cat. CS and PFK activities correlated positively, and LDH activity correlated negatively, with in vitro fatigue resistance assessed after 5 min of repetitive stimulation in cat. These data indicate close relationships between metabolic profiles, particularly oxidative capacity, and fatigue resistance of pharyngeal muscles in relationship to each other and to the diaphragm.
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PMID:Metabolic profiles of cat and rat pharyngeal and diaphragm muscles. 893 Nov 76


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