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

Muscle biopsies taken from the musculus quadriceps femoris of man were analysed for pH, ATP, ADP, AMP, creatine phosphate, creatine, lactate and pyruvate. Biopsies were taken at rest, after circulatory occlusion and after isometric contraction. Muscle pH decreased from 7.09 at rest to 6.56 after isometric exercise to fatigue. Decrease in muscle pH was linearly related to accumulation of lactate plus pyruvate. An increase of 22mumol of lactate plus pyruvate per g of muscle resulted in a fall of 0.5pH unit. The apparent equilibrium constant of the creatine kinase reaction (apparent K(CK)) increased after isometric contraction and a linear relationship between log(apparent K(CK)) and muscle pH was obtained. The low content of creatine phosphate in muscle after contraction as analysed from needle-biopsy samples is believed to be a consequence of an altered equilibrium state of the creatine kinase reaction. This in turn is attributed mainly to a change in intracellular pH.
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PMID:Creatine kinase equilibrium and lactate content compared with muscle pH in tissue samples obtained after isometric exercise. 0 60

The metabolic effects of 60-min exposure to 250-2000 mg gamma-hydroxybutyrate (GHB) per kilogram or 150-1200 mg gamma-butyrolactone (GBL) per kilogram were studied in rats by measurement of the cerebral hemisphere contents of energy phosphates and glycolytic-Krebs' cycle metabolites. A general pattern of increased glycogen and glucose with decreased pyruvate, lactate, alpha-ketoglutarate, and malate was observed. This pattern in association with unchanged adenylates and decreased energy phosphate utilization was consistent with a metabolic adaptation to a state of cerebral depression. The major qualitative difference between the two drugs was that higher doses of GBL were associated with additional decreases of citrate and glutamate. Since these doses of GBL were also associated with acute increases of arterial CO2 tension, it is proposed that these differences were secondary to hypercapnia and not due to a distinctive primary action of GBL. Derivation of the cytoplasmic NAD(P)H:NAD(P)+ ratios indicated that GHB and GBL were not associated with consistent alterations of the cytoplasmic redox state.
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PMID:A comparison of the effects of gamma-hydroxybutyrate and gamma-butyrolactone on cerebral carbohydrate metabolism. 4 Jun 77

Phosphate diabetes has been considered as rare and to occur almost exclusively in children. Upon examination of adult patients with rheumatic or kidney diseases it has, however, been found that the combination of hypophosphataemia and hyperphosphaturia is not so rare. This paper deals with 24 adult patients of this type, whom we have found during 6 months. Their mean serum phosphorus concentration was 0.7 mmol/l (range 0.5--0.8). Mean phosphate clearance was 31 ml/min/1.73 m2 (range 16--51). The diagnoses were myalgia, dorsalgia (n = 7), papillitis calcificans (n = 5), prostatitis or prostate accretions (n = 4), dizziness (n = 2), kidney stones, tubular defect, interstitial nephritis, medullary sponge kidney (1 case each), two patients had transplanted kidneys. Asthenia was a common additional diagnosis. The patients' complaints have been pain in the muscles, joints, bones (18 cases), tiredness (10 cases), dizziness (8 cases), shakyness, numbness, burning sensation (7 cases), tenderness in the muscles and bones ("the princess-on-the-pea syndrome") (7 cases). The most common findings upon examination were bone tenderness (13 cases), reduced manual power (8 cases), positive Romberg test (3 cases), slight muscle atrophy (2 cases), waddling gait (2 cases). The most common findings encountered in the laboratory, besides hypophosphataemia and hyperphosphaturia, were high pH in the urine, hyperaminoaciduria, and phosphate crystals in dried urine.
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PMID:Mild phosphate diabetes in adults. 30 93

Fourteen patients with a variety of neoplasms not responsive to standard forms of therapy underwent whole body hyperthermia for a maximum 4 h at 41.8 degrees C. This was a phase-I cancer trial designed to develop whole body hyperthermia as an adjuvant to systemic chemotherapy. Intravenous analgesia was used to sedate patients, obviating the need for general endotracheal anesthesia. Hyperthermia was induced by means of a high-flow water perfusion suit. Cardiovascular performance was evaluated using a flow-directed pulmonary artery catheter. Patients developed a twofold mean increase in cardiac index without evidence of cardiac damage by ECG or creatine phosphokinase (CPK) isoenzymes. An acute fall in serum magnesium and phosphate and an acute rise in arterial pH, serum CPK values, and granulocyte count occurred in all patients. There were no clotting abnormalities. Toxicity included fatigue, diarrhea, nausea, and transient elevations in liver enzymes. Four patients were febrile for 36 h after initial defervescence. Peripheral neuropathy developed in four. These results show that with carefully monitored conditions whole body hyperthermia is feasible.
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PMID:Whole body hyperthermia: a phase-I trial of a potential adjuvant to chemotherapy. 42 99

During studies of the regulation of phosphorylase activity and glycogenolysis in contracting muscle, it was found that conversion of phosphorlyase beta to alpha is transient. Reversal of phosphorylase activation during both continuous and intermittent stimulation in the plantaris might, in part, have been due to development of fatigue. However, a complete reversal of phosphorylase activation was also evident within 5 min in the absence of fatigue in soleus muscles stimulated tetanically with 100-ms-long trains at a rate of 60/min. These muscles showed no significant decline in contractile force. Glycogen breakdown stopped in the soleus when phosphorylase reverted to the beta form, providing evidence that phosphorylase beta was not active. This lack of activity is probably explained by the finding that ATP and AMP concentrations changed little, while glucose 6-phosphate increased. Reversal of phosphorlyase activation soon after the onset of steady-state work may be a mechanism for conserving glycogen when the supply of other substrates is adequate to meet the muscles' energy needs.
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PMID:Reversal of phosphorylase activation in muscle despite continued contractile activity. 49 77

The effect of 1.5 to 2.5 h tourniquet ischemia on energy metabolism of the quadriceps muscle was studied using percutaneous needle biopsy technique in sixteen patients operated on for an inveterated knee injury. During occlusion there was a moderate decrease in ATP with an increase in ADP and AMP. This change resulted in a decreased energy charge potential. At the same time phosphorylcreatine (PC) decreased markedly while creatine (Cr) increased giving a constant total creatine (TCr). An accumulation of lactate during occlusion with values up to 80 mmol/kg d.m. (dry muscle) was seen. A 15% reduction in glycogen was calculated. After release of the tourniquet the active phosphate concentration and the energy charge potential returned to basal levels within 5 min and most of the metabolites in the glycolytic sequence were also normalized. Muscle lactate content was normal after 30 min of intact circulation. The results suggest that longterm tourniquet ischemia induces marked changes in energy metabolism in skeletal muscle, but that the changes are rapidly and completely reversible with restoration of blood flow.
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PMID:The effect of long-term arterial occlusion on energy metabolism of the human quadriceps muscle. 52 75

Between 20 July and 15 Octoboer 1975, five cases of human infection with Babesia microti were diagnosed on Nantucket Island, Massachusetts. The illness was characterized by fever, drenching sweats, shaking chills, myalgia, arthralgia, extreme fatigue, and a mild-to-moderate hemolytic anemia. None of the patients had a history of splenetomy. Although all patients responded symptomatically to treatment with oral chloroquine phosphate, parasitemia and fatigue frequently persisted for several weeks to months.
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PMID:Human babesiosis on Nantucket Island. Clinical features. 55 20

1. After severe muscular contraction in man recovery of force is largely complete in a few minutes, but is not wholly so for many hours. The long-lasting element of fatigue is found to occur primarily for low frequencies of stimulation (e.g. 20/sec), and is much less pronounced, or absent, at high frequencies (80/sec). The twitch force is an unreliable measure of the state of fatigue. 2. The long-lasting element of fatigue is not due to depletion of high-energy phosphate nor is it due to failure of electrical activity as recorded from surface electrodes. It is probably the result of an impairment of the process of excitation-contraction coupling. Its practical importance for man could be significant as an explanation of the subjective feelings of weakness following exercise.
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PMID:Fatigue of long duration in human skeletal muscle after exercise. 59 14

1. Adaptive mechanisms of oxygen transport by blood have been studied in severely anaemic young patients on maintenance haemodialysis, in conditions of hyperphosphataemia (Pi greater than or equal to 2.2 mmol/l) or normophosphataemia. 2. In hyperphosphataemia whole-blood affinity for oxygen was slightly decreased, as measured by an increase in P50 (the partial pressure of oxygen necessary to half saturate haemoglobin). 2,3-Diphosphoglycerate was increased by 10% (P less than 0.10) whereas Pi, total erythrocyte phosphate and ATP were increased by 100%, 47% and 36% respectively, compared with control values. 3. After correction of hyperphosphataemia a small but significant decrease in P50 and 2,3-diphosphoglycerate, to normal values, was observed whereas the other variables, although significantly lowered, remained above control values. 4. In these severely anaemic and hyperphosphataemic patients P50 and 2,3-diphosphoglycerate are only slightly increased. ATP synthesis appears to be favoured over that of 2,3-diphosphoglycerate. This is possibly due to alterations in the erythrocyte membrane elicited by bi-weekly extracorporeal circulation. Adequate oxygen transport can be achieved only through a drastic increase in blood flow. Correction of hyperphosphataemia adds further to the abnormality. It is concluded that this condition could induce a long-term myocardial fatigue, which might be prevented with occasional small blood transfusions.
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PMID:Oxygen transport in children on maintenance haemodialysis. 62 Apr 97

In aerial combat maneuvers (ACMs), at Luke AFB, Az, eight pilots flew their two F-15 aircraft against nine pilots in three F-106 aircraft. A total of nine flights, consisting of 23 ACMs, were accomplished in 5 successive days. The degrees of fatigue, stress, and sympathetic activity were quantified using both subjective analyses and the biochemical constituents in the urine of the pilots of the F-15 or F-106. Biochemical indicators, reported per 100 mg creatinine, included: epinephrine, norepinephrine, 17-OHCS, urea, inorganic phosphate, sodium, potassium, and sodium/potassium ratio. The F-106 pilots exerted more relative effort than did the F-15 pilots--effort which appeared to be associated with high-G experience. Both groups of pilots were equally fatigued following ACMs; however, only the fatigue of the F-106 pilots was directly correlated with the length of the ACM. Sympathetic and stress responses during the ACM--similar for both groups of pilots--showed postflight increases of 54% in epinephrine, 19% in norepinephrine, and 20% in 17-OHCS over preflight values, thus suggesting a moderate stress response. Resting levels of these same indicators, for days the pilots did not fly and for pre-ACM values, were similar but higher than control values previously reported for other stressful activities. By late afternoon, postflight values for these indicators had returned to near-preflight levels.
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PMID:Stress responses of pilots flying high-performance aircraft during aerial combat maneuvers. 87 Dec 90


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