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

Eccentric muscle contractions generate delayed onset muscle soreness (DOMS), possibly as a result of the high tensions involved causing muscle damage. Muscle function, serum indicators of muscle damage, and DOMS were investigated throughout a training regimen that involved a 40-min eccentric walk down a 25% gradient on a treadmill at 6.4 km/h once a week for 8 wk. Serum creatine kinase and myoglobin concentrations were used as indicators of muscle damage, and both demonstrated a delayed increase after the exercise protocol. The muscles that contracted eccentrically exhibited low-frequency fatigue, as well as decreases in muscle fatigability and maximal voluntary contraction force, which were greatest immediately postexercise. Although the results show that training reduces DOMS, the serum muscle protein response, and muscle function impairment, the time courses of these adaptations are different. It is suggested that the function of the muscle can be impaired without apparent muscle damage.
 ...
PMID:Effect of training on eccentric exercise-induced muscle damage. 828 2

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.
 ...
PMID:[A case of rhabdomyolysis complicated with myocardial injury]. 856 47

Oral L-carnitine has been reported to lower the elevated serum myoglobin of renal failure in chronic peritoneal dialysis patients, and intravenous L-carnitine can improve muscle fatigue and cramps in chronic hemodialysis patients. In this study oral L-carnitine, 1.98 g/day, was administered to 6 chronic hemodialysis patients for 8 weeks. Serum levels of myoglobin, creatine kinase, and aldolase, as well as skeletal muscle symptoms (cramps during dialysis, fatigue, and weakness) were monitored biweekly for 12 weeks. Mean baseline serum myoglobin level was 337 +/- 34 ng/mL. By 6 and 8 weeks mean serum myoglobin was 234 +/- 39 and 233 +/- 40 ng/mL, significantly lower by the Friedman test (p < 0.05). Four weeks after carnitine was discontinued, mean serum myoglobin had risen to 320 +/- 118 ng/mL. Serum creatine kinase and aldolase levels were normal throughout the study. All 6 patients noted improvement in muscular symptoms, with maximal effect at 8 weeks, although 2 patients did not improve until 2 to 4 weeks after carnitine was stopped. We conclude that oral L-carnitine may lower serum myoglobin and improve muscle cramps and weakness in hemodialysis patients. The maximal effect of carnitine on myoglobin occurs 2 weeks before the maximal improvement in muscular symptoms.
 ...
PMID:Effect of oral L-carnitine on serum myoglobin in hemodialysis patients. 882 May 5

Recent progress in defining molecular components of pathways controlling early stages of myogenesis has been substantial, but regulatory factors that govern the striking functional specialization of adult skeletal muscle fibers in vertebrate organisms have not yet been identified. A more detailed understanding of the temporal and spatial patterns by which specialized fiber characteristics arise may provide clues to the identity of the relevant regulatory factors. In this study, we used immunohistochemical, in situ hybridization, and Northern blot analyses to examine the time course and spatial characteristics of expression of myoglobin protein and mRNA during development of the distal hindlimb in the mouse. In adult animals, myoglobin is expressed selectively in oxidative, mitochondria-rich, fatigue-resistant myofibers, and it provides a convenient marker for this particular subset of specialized fibers. We observed only minimal expression of myoglobin in the hindlimb prior to the second day after birth, but a rapid and large (50-fold) induction of this gene in the ensuing neonatal period. Myoglobin expression was limited, however, to fibers located centrally within the limb which coexpress myosin isoforms characteristic of type I, IIA, and IIX fibers. This induction of myoglobin expression within the early postnatal period was accompanied by increased expression of nuclear genes encoding mitochondrial proteins, and exhibited a time course similar to the upregulation of myoglobin and mitochondrial proteins, and exhibited a time course similar to the upregulation of myoglobin and mitochondrial protein expression that can be induced in adult muscle fibers by continuous motor nerve stimulation. This comparison suggests that progressive locomotor activity of neonatal animals may provide signals which trigger the development of the specialized features of oxidative, fatigue-resistant skeletal muscle fibers.
 ...
PMID:Postnatal development and plasticity of specialized muscle fiber characteristics in the hindlimb. 890 47

The stretch-shortening cycle (SSC) is an effective and natural form of muscle function but, when repeated with sufficient intensity or duration, it may lead to muscle damage and functional defects. A reduced tolerance to impact has been reported, which may be partly attributed to a reduced stretch-reflex potentiation. The aim of the present study was to examine the influence of SSC-induced metabolic fatigue and muscle damage on the efficacy of stretch reflexes, as judged by the electromyograph (EMG) response of two shank muscles (lateral gastrocnemius LG, soleus SOL) to controlled ramp stretches. These EMG responses were recorded before and immediately after exhausting SSC-type leg exercise and 2 h, 2 days and 4 days later. Serum concentrations of creatine kinase ([CK]), myoglobin and lactate were measured repetitively along the protocol. Two maximal vertical drop jumps and counter-movement jumps were performed after each reflex test. The exhausting SSC-type exercise induced an immediate reduction (P < 0.05) with a delayed short-term recovery of the LG peak-to-peak reflex amplitude. This was not accompanied by significant changes in the reflex latency. The drop jump performance remained slightly but significantly reduced (P < 0.05) until the 2nd day postexercise. Peak [CK] appeared for all the subjects on the 2nd day, suggesting the presence of muscle damage. The increase in [CK] between the 2nd h and the 2nd day postexercise was found to be negatively related (P < 0.001) to the relative changes in the drop jump height. Furthermore, a significant relationship (P < 0.05) was found between recovery of the stretch reflex in LG and the decrease of [CK] between the 2nd and the 4th day. These findings support the hypothesis of a reduced stretch-reflex sensitivity. While the exact mechanisms of the reflex inhibition remain unclear, it is emphasized that the delayed recovery of the reflex sensitivity could have resulted from the progressive inflammation that develops in cases of muscle damage.
 ...
PMID:Reduced stretch-reflex sensitivity after exhausting stretch-shortening cycle exercise. 892 9

We have developed a reproducible low-dose endotoxin model which is useful for the investigation of early SIRS. The data confirm that organ function cannot be inferred from whole animal data (e.g. SVR vs. MVR). Thus, the study of SIRS at the organ and cellular level is essential. Decreased skeletal muscle oxygen consumption with 4 Hz exercise in early SIRS may be related to depletion of physiologic reserves, especially microcirculatory reserves, as suggested by decreased myoglobin saturation and decreased energy charge. Using this model, we will investigate whether organ dysfunction in SIRS is due to oxygen-limited cellular ATP production or impaired cellular metabolism.
 ...
PMID:Skeletal muscle function, oxygenation and biochemistry in an endotoxemic model of SIRS. 950 67

To examine the effects of rapid dehydration on isometric muscular strength and endurance, seven men were tested at baseline (control) and after a dehydration (dHST) and a euhydration (eHST) heat stress trial. The dHST consisted of intermittent sauna exposure until 4% of body mass was lost, whereas the eHST consisted of intermittent sauna exposure (same duration as dHST) with water replacement. Peak torque was determined for the knee extensors and elbow flexors during three isometric maximal voluntary contractions. Time to fatigue was determined by holding a maximal voluntary contraction until torque dropped below 50% peak torque for 5 s. Strength and endurance were assessed 3.5 h after the HSTs (no food or water intake). Body mass was decreased 3.8+/-0.4% post dHST and 0.4+/-0.3% post eHST. Plasma volume was decreased 7.5+/-4.6% and 5.7+/-4.4%, 60 and 120 min post dHST, respectively. A small (1.6 mEq x L[-1]) but significant increase was found for serum Na+ concentration 60 min post dHST but had returned to predehydration level 120 min post dHST. Serum K+ and myoglobin concentrations were not affected by HSTs. Peak torque was not different (P > 0.05) among control, dHST, and eHST for the knee extensors (Mean (Nm)+/-SD, 285+/-79, 311+/-113, and 297+/-79) and elbow flexors (79+/-12, 83+/-15, and 80+/-12). Time to fatigue was not different (P > 0.05) among control, dHST and eHST for the knee extensors (Mean (s)+/-SD. 42.4+/-11.5, 45.3+/-7.6, and 41.8+/-6.0) and elbow flexors (48.2+/-8.9, 44.0+/-9.4, and 46.0+/-6.4). These results provide evidence that isometric strength and endurance are unaffected 3.5 h after dehydration of approximately 4% body mass.
 ...
PMID:Effects of dehydration on isometric muscular strength and endurance. 950 58

In paraplegic patients, shoulder complaints attributable to muscle dysbalances arising from the particular daily form of exercise are often observed. The goal of therapy is to correct these imbalances through muscular training, whereby eccentric exercise might offer advantages due to lower fatigue with concurrent higher maximum strength. This study therefore examines muscle fatigue, maximum strength, and suitability for paraplegics of eccentric exercise of the shoulder. Muscle fatigue, isokinetic peak torque, and EMG activity were determined eccentric (Ecc) and concentric (Con) in 41 paraplegic subjects (13 early rehabilitants; 16 trained in wheelchair sports; 12 untrained). Serum CK, myoglobin, and subjective pain were collected for one week after exercise. In eccentric exercise, there was less muscle fatigue in all groups. Highest Ecc/Con peak torque ratio was found in trained subjects in all movements, followed by the untrained and the early rehabilitants. EMG-activity was lower in eccentric compared to concentric exercise (Ecc/Con ratio <1). CK and myoglobin concentrations, like pain symptoms, showed a marked increase after exercise. It is concluded that the Ecc/Con strength patterns among paraplegics are altered. Eccentric exercise offers advantages on the basis of lower muscular fatigue independent of training status and lesion time and higher maximum strength with increasing duration of paraplegia and additional athletic training. However, due to structural damage and subjective pain eccentric exercise can only be recommended with reservations in therapy and training.
 ...
PMID:Muscular fatigue, maximum strength an stress reactions of the shoulder musculature in paraplegics. 1055 45

The biochemical basis for the regulation of fibre-type determination in skeletal muscle is not well understood. In addition to the expression of particular myofibrillar proteins, type I (slow-twitch) fibres are much higher in mitochondrial content and are more dependent on oxidative metabolism than type II (fast-twitch) fibres. We have previously identified a transcriptional co-activator, peroxisome-proliferator-activated receptor-gamma co-activator-1 (PGC-1 alpha), which is expressed in several tissues including brown fat and skeletal muscle, and that activates mitochondrial biogenesis and oxidative metabolism. We show here that PGC-1 alpha is expressed preferentially in muscle enriched in type I fibres. When PGC-1 alpha is expressed at physiological levels in transgenic mice driven by a muscle creatine kinase (MCK) promoter, a fibre type conversion is observed: muscles normally rich in type II fibres are redder and activate genes of mitochondrial oxidative metabolism. Notably, putative type II muscles from PGC-1 alpha transgenic mice also express proteins characteristic of type I fibres, such as troponin I (slow) and myoglobin, and show a much greater resistance to electrically stimulated fatigue. Using fibre-type-specific promoters, we show in cultured muscle cells that PGC-1 alpha activates transcription in cooperation with Mef2 proteins and serves as a target for calcineurin signalling, which has been implicated in slow fibre gene expression. These data indicate that PGC-1 alpha is a principal factor regulating muscle fibre type determination.
 ...
PMID:Transcriptional co-activator PGC-1 alpha drives the formation of slow-twitch muscle fibres. 1218 55

Two cases of alcoholics associated with rhabdomyolysis and acute renal failure were reported. Case 1 was a 67-year-old male who had complained of general fatigue and generalized muscle pain. He had drunken and slept outdoor in winter until he was found. Laboratory data on admission showed remarkable elevation of muscle enzymes (AST, LDH, CPK) and serum levels of myoglobin, BUN, and Cr. He was treated with hemodialysis because of acute renal failure caused by rhabdomyolysis and recovered from renal failure. Case 2 was a 50-year-old male who had been unconscious and suffered from muscle weakness. He had drunken and slept in the bed for several days without eating any food until he was found by his sister. Laboratory data on admission showed remarkable elevation of muscle enzymes and serum levels of myoglobin, BUN, and Cr. It also showed hypoglycemia and hyponatremia. He developed into acute renal failure caused by rhabdomyolysis, but had a good clinical course without hemodialysis. The rhabdomyolysis of case 1 might have been caused by alcohol and sleeping outdoor in winter. That of case 2 might have been caused by alcohol and pressure necrosis due to immobility for several days in his bed.
 ...
PMID:[Two cases of alcoholics associated with rhabdomyolysis and acute renal failure]. 1246 66


<< Previous 1 2 3 4 5 6 7 8 Next >>