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

To investigate the safety of rapid infusion of alendronate, we used alendronate therapy for 11 breast cancer patients with bone metastasis. Of the 11 patients, only 1 had hypercalcemia and the remaining 10 normocalcemia. Rapid infusion of alendronate consisted of an administration of alendronate 10 mg diluted in 100 ml saline in 30 minutes, and was repeated every two weeks. Each patient underwent 1 to 9 alendronate treatments. During alendronate therapy, only one patient complained of general fatigue, and the remaining 10 showed no alendronate-induced clinical symptoms. Rapid infusion of alendronate caused an increase in BUN level in two patients receiving intravenous hyperalimentation (IVH), a mild increase of GOT level in one, and a decrease of serum phosphorus level in two receiving IVH. However, no increase was found in serum creatinine and GOT levels. In addition, no patients showed alendronate-induced hypocalcemia. In conclusion, rapid infusion of alendronate brings about no major adverse effects, and makes it easier for many patients with bone metastasis to receive alendronate therapy on an outpatient basis.
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PMID:[A study of the safety of rapid infusion of alendronate]. 1006 98

Titanium alloy (ASTM F-136) rods were coated with hydroxyapatite (HA) of 3 levels of crystallinity, which were determined by X-ray diffraction (XRD) analysis to be 60.5%, 52.8%, and 47.8%. Fourier Transform Infrared (FTIR) spectroscopy analysis showed the removal of the hydroxyl and carbonate groups as compared to the original HA powder. It appears that these changes are caused by the high temperature plasma spray coating process. Cyclic fatigue testing in a lactated Ringer's solution to 5 million cycles showed no statistical difference in calcium dissolution among the 3 crystalline levels, whereas phosphorus dissolution was lowest from the highest crystalline coating sample. The mechanical properties, however, did not change in response to fatigue loading.
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PMID:Cyclic fatigue of hydroxyapatite-coated titanium alloy implant material--effect of crystallinity. 1016 58

A double-blind placebo-controlled cross-over trial was undertaken to evaluate the effect of antioxidant supplementation on maximal oxygen uptake during bicycling, 31-phosphorus nuclear magnetic response spectroscopy (31P-NMRS) detected muscle energy metabolism during plantar flexion and muscle fatigue evaluated by 1-s electrical stimulation at low (10 Hz) and high (50 Hz) frequency. Seven male triathletes received daily oral antioxidant supplementation in capsule form including 100 mg coenzyme Q10 (CoQ10), 600 mg ascorbic acid and 270 mg alpha-tocopherol or placebo over a 6-week interval. Serum concentration of CoQ10 was significantly higher in the antioxidant phase (1.80+/-1 microg x ml(-1), mean +/- SD) than control (0.9+/-0.21 microg ml(-1)) or placebo phase (0.9+/-0.3 microg x ml(-1)) (P<0.01). Maximal oxygen uptake was 63.8+/-3.0 ml x min(-1) x kg(-1) in the control phase, and did not change significantly in the antioxidant (67.6+/-10.8 ml x min(-1) x kg(-1)) or the placebo phase (61.9+/-4.5 ml x min(-1) x kg(-1)). The combined 31P-NMRS/low frequency fatigue test (plantar flexion of the foot) did not show differences in the gastrocnemius muscle pH (6.77+/-0.14), phosphocreatine reduction at the end of exercise (23+/-14% of rest) and half-time for recovery of phosphocreatine (33+/-12 sec) between the placebo and the antioxidant trial. No difference in muscle fatigue at 10 Hz electrical stimulation was found between the three phases. In conclusion, the results demonstrate no effect of antioxidative vitamin supplementation on maximal oxygen uptake, muscle energy metabolism or muscle fatigue in triathletes.
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PMID:No effect of antioxidant supplementation in triathletes on maximal oxygen uptake, 31P-NMRS detected muscle energy metabolism and muscle fatigue. 1033 91

A major issue associated with functional electrical stimulation (FES) of a paralyzed limb is the decay with time of the muscle force as a result of fatigue. A possible means to reduce fatigue during FES is by using interrupted stimulation, in which fatigue and recovery occur in sequence. In this study, we present a model which enables us to evaluate the temporal force generation capacity within the electrically activated muscle during first stimulation fatigue, i.e., when the muscle is activated from unfatigued initial conditions, and during postrest stimulation, i.e., after different given rest durations. The force history of the muscle is determined by the activation as derived from actually measured electromyogram (EMG) data, and by the metabolic fatigue function expressing the temporal changes of muscle metabolites, from existing data acquired by in vivo 31P MR spectroscopy in terms of the inorganic phosphorus variables, Pi or H2PO4-, and by the intracellular pH. The model was solved for supra-maximal stimulation in isometric contractions separated by rest periods, and compared to experimentally obtained measurements. EMG data were fundamental for prediction of the ascending force during its posttetanic response. On the other hand, prediction of the decaying phase of the force was possible only by means of the metabolite-based fatigue function. The prediction capability of the model was assessed by means of the error between predicted and measured force profiles. The predicted force obtained from the model in first stimulation fatigue fits well with the experimental one. In postrest stimulation fatigue, the different metabolites provided different prediction capabilities of the force, depending on the duration of the rest period. Following rest duration of 1 min, Pi provided the best prediction of force; H2PO4- extended the prediction capacity of the model to up to 6 min and pH provided a reliable prediction for rest durations longer than 12 min. The results presented shed light on the roles of EMG and of metabolites in prediction of the force history of a paralyzed muscle under conditions where fatigue and recovery occur in sequence.
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PMID:EMG and metabolite-based prediction of force in paralyzed quadriceps muscle under interrupted stimulation. 1049 76

Six healthy subjects rapidly lifted and lowered a small (250 g) weight with the first dorsal interosseous muscle (FDI) of one hand while the work performed was recorded continuously until fatigue (defined as losing the ability to continue lifting). Work was recorded in units of chart recorder trace displacement from baseline (centimeters) as an isotonic transducer followed the movement of the weight. In all experiments, the temperature of the hand was first adjusted by immersion in a controlled-temperature water bath. In the warmest condition, the skin surface temperature over the FDI was 30.5(0.30) degrees C [mean (SE)]. After moderate cooling, this surface temperature was 21.5(0.16) degrees C. Cooling significantly reduced the time taken to reach fatigue and more than halved the work capacity. An intermediate degree of cooling was also used in four subjects, showing that most of the effects seen were changing incrementally. Before work, and at fatigue, intracellular metabolic conditions in the FDI were studied by phosphorus nuclear magnetic resonance (31P-NMR) spectroscopy, with occlusion of the blood flow maintained during measurements. The mean intracellular pH of the FDI was also calculated. The changes observed were all consistent with the fact that intense work requires energy which must be derived largely from intracellular stores of phosphocreatine and glycogen. Less work made less demand upon reserves, and created lower concentrations of waste products and by-products. The observations did not, however, allow us to explain why fatigue occurred at a particular point or why work capacity was reduced by cooling.
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PMID:Influence of muscle temperature during fatiguing work with the first dorsal interosseous muscle in man: a 31P-NMR spectroscopy study. 1063 78

In recent years, investigations into cardiac rehabilitation have suggested that bicycle exercise training increases peak oxygen uptake of patients with chronic heart failure(CHF). However, some patients can not perform such exercise because of poor cardiac function. If patients were able to achieve metabolic improvement in their muscles by localized small muscle group training, it would be advantageous for these patients. Therefore, in patients with CHF, we investigated whether localized skeletal muscle training improved calf muscle metabolism. Seven patients undertook a random order crossover trial. Training consisted of unilateral calf plantar flexion exercise. After training, phosphorus-31 nuclear magnetic resonance spectroscopy revealed significant improvements in calf muscle metabolism in patients with CHF. Subjective fatigue score was also improved. In this paper, stress testing in cardiology and cardiac rehabilitation including the above experimental data were introduced.
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PMID:[Stress testing in cardiology and cardiac rehabilitation]. 1080 13

To evaluate the features of primary hyperparathyroidism (HPT) with normal serum intact parathyroid hormone (iPTH) levels, we studied 271 consecutive patients undergoing surgery for primary HPT. In 20 patients, serum iPTH levels were within the normal range (10-65 ng/l). In their records, the most common clinical features were fatigue (n=13), polyuria (n=6), renal stone (n=5), and hypertension (n=5). Mean serum calcium and phosphorus were 2.78 and 0.85 mmol/l, respectively: 14 had serum phosphorus within the normal range. Mean serum iPTH was 48.5 ng/l, and was <45 ng/l in nine patients. Cervical ultrasound demonstrated a parathyroid adenoma in nine, and was normal in four. Tc sestamibi parathyroid scintigraphy always demonstrated an adenoma (9/9). In eight patients, normal iPTH values delayed diagnosis. Physicians should be aware of the possibility of HPT in patients with hypercalcaemia, even when serum phosphorus and iPTH levels are within the normal limits. Particularly, HPT cannot be excluded when serum iPTH levels are below the upper part of the normal range. In such cases, cervical imaging, which has the same sensitivity as in other HPT, should be undertaken. These explorations are useful, because many patients are symptomatic and can take advantage of surgery.
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PMID:Primary hyperparathyroidism with normal serum intact parathyroid hormone levels. 1087 86

Phosphorus magnetic resonance spectroscopy (P-MRS) has now been used in the investigation of muscle energy metabolism in health and disease for over 15 years. The present review describes the basics of the metabolic observations made by P-MRS including the assumptions and problems associated with the use of this technique. Extramuscular factors, which may affect the P-MRS results, are detailed. The important P-MRS observations in patients with mitochondrial myopathies, including the monitoring of experimental therapies, are emphasized. The findings in other metabolic myopathies (those associated with glycolytic defects or endocrine disturbances) and in the destructive myopathies (the dystrophies and the inflammatory myopathies) are also described. Observations made in normal and abnormal fatigue, fibromyalgia, and malignant hyperthermia are considered. Finally, a summary of the possible diagnostic use of P-MRS in exercise intolerance is provided.
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PMID:Insights into muscle diseases gained by phosphorus magnetic resonance spectroscopy. 1095 34

This paper examined the role of metabolites in causing muscle fatigue. Previous studies have shown that Pi (H2PO4-, HPO4-2) and H+ may be important factors in causing fatigue. A key question is the potential interaction between metabolic end-products and calcium related excitation-contraction coupling fatigue (ECC). An in vivo rat muscle model was used to measure tension development and metabolic end-products in response to electrical stimulation. Two stimulation protocols were used, high intensity stimulation followed by a medium intensity stimulation (High Group), and low intensity stimulation followed by a medium intensity stimulation (Low Group). Metabolic fatigue was based on concentrations of (H2PO4-measured with phosphorus magnetic resonance spectroscopy. ECC fatigue was measured as the fatigue in excess of metabolic fatigue, and as the relative decline of force at low compared to high stimulation frequencies. During the initial stimulation period, the High Group had greater metabolic fatigue (p < 0.001) and greater ECC fatigue (p = 0.007). During the second stimulation period and recovery, the High Group had no difference in metabolic fatigue (p = 0.07) and greater ECC fatigue (p = 0.015). These results present a method for determining the relative amounts of metabolic and ECC fatigue, and suggest that metabolites can increase the amount of ECC fatigue.
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PMID:Muscle fatigue: the role of metabolism. 1188 Jun 92

Energy metabolism and electrical muscle activity were studied in the calf muscles of 19 patients with proven McArdle's disease and in 25 healthy subjects. Phosphorus magnetic resonance spectroscopy and surface electromyography (S-EMG) were performed during two isometric muscle contractions of 3 min at 30% maximum voluntary contraction, one performed during normal perfusion and the other during applied ischemia. After about 1 min of ischemic muscle contraction in diseased muscle a significant acceleration in phosphocreatine breakdown was observed, along with a significant decrease in adenosine triphosphate. During both contractions the absence of glycolysis was shown by a significant alkalinization. Furthermore, in patients we observed a greater increase in the S-EMG amplitude than in control subjects. We conclude that early on during moderate exercise, a small number of muscle fibers reach metabolic depletion, indicated by a reduction in the adenine nucleotide pool. An increasing number of motor units, which are still in a high-energy state, are continuously recruited to compensate for muscle fatigue. This functional compartmentation may contribute to the pathophysiology of exercise intolerance in McArdle's disease.
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PMID:Breakdown of adenine nucleotide pool in fatiguing skeletal muscle in McArdle's disease: a noninvasive 31P-MRS and EMG study. 1276 85


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