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)

Intermittent hyperthyreosis occurs under various forms of stress, especially heat stress. The clinician may diagnose such cases as masked or apathetic hyperthyroidism or "forme fruste" hyperthyreosis or thyroid autonomy. As most routine and standard tests may here yield inconsistent results, it is the patients' anamnesis which may provide the clue. Our Bioclimatology Unit has now seen over 100 cases in which thyroid hypersensitivity towards heat was the most prominent syndrome: 10-15% of weather-sensitive patients are affected. The patients complain before or during heat spells of such contradictory symptoms as insomnia, irritability, tension, tachycardia, palpitations, precordial pain, dyspnoe, flushes with sweating or chills, tremor, abdominal pain or diarrhea, polyuria or pollakisuria, weight loss in spite of ravenous appetite, fatigue, exhaustion, depression, adynamia, lack of concentration and confusion. Determination of urinary neurohormones allows a differential diagnosis, intermittent hyperthyreosis being characterized by three cardinal symptoms: 1. tachycardia -- every case with more than 80 pulse beats being suspect (not specific); 2. urinary histamine -- every case excreting more than 90 mug/day being suspect. Again the drawback of this test is its lack of specificity, as histamine may also be increased in cases of allergy and spondylitis; 3. urinary thyroxine -- every case excreting more than 20 mug/day T-4 being suspect. This is the only specific test. Therapy should make use of lithium carbonate and beta-blockers. Propyl thiouracil is rarely required.
 ...
PMID:Intermittent hyperthyreosis -- a heat stress syndrome. 5 84

There is considerable debate regarding the ergogenic effects of sodium bicarbonate (NaHCO3) on racing performance in horses. Anecdotal evidence suggests that NaHCO3 improves performance by increasing the buffering capacity of the blood and delaying the onset of hydrogen ion-induced fatigue. In a cross-over study, 16 Thoroughbred racehorses were given an aqueous solution of NaHCO3 (0.4 g/kg in 1 litre H2O) or a control treatment (1 litre H2O) before a 1600-m race. Treatments were administered 3 h before the race, which was the time to peak buffering capacity (2.5-3.0 h) determined in a separate study. Before the race, there was a significant increase in venous HCO3- and pH in the NaHCO3-treated horses. After the race, there was a significant increase in venous blood pH and lactate in the NaHCO3-treated horses. Collectively, the data suggest an improved buffering capacity of the blood after NaHCO3 treatment. However, there was no change in race times or venous partial pressure of carbon dioxide. Therefore, the administration of NaHCO3 provided no ergogenic benefit to horses competing in a 1,600-m race.
 ...
PMID:Effects of induced alkalosis on performance in thoroughbreds during a 1,600-m race. 131 65

1. The performance of skeletal muscle during repetitive stimulation may be limited by the development of an intracellular acidosis due to lactic acid accumulation. To study this, we have measured the intracellular pH (pHi) with the fluorescent indicator BCECF (2',7'-bis(carboxyethyl)-5(6)- carboxyfluorescein) during fatigue produced by repeated, short tetani in intact, single fibres isolated from the mouse flexor brevis muscle. 2. The pHi at rest was 7.33 +/- 0.02 (mean +/- S.E.M., n = 29, 22 degrees C). During fatiguing stimulation pHi initially went alkaline by about 0.03 units (maximum alkalinization after about ten tetani). Thereafter pHi declined slowly and at the end of fatiguing stimulation (tetanic tension reduced to 30% of the original; 0.3Po), pHi was only 0.063 +/- 0.011 units (n = 14) more acid than in control. 3. We considered three possible causes of acidosis being so small in fatigue: (i) a high oxidative capacity so that fatigue occurs without marked production of lactic acid; (ii) an effective transport of H+ or H+ equivalents out of the fibres; a high intracellular buffer power. 4. The oxidative metabolism was inhibited by 2 mM-cyanide in three fibres. After being exposed to cyanide for 5 min without stimulation, the tetanic tension was reduced to about 0.9 Po and pHi was alkaline by about 0.1 units. The fibres fatigued faster in cyanide and the pHi decline in fatigue was more than twice as large as that under control conditions. 5. Inhibition of Na(+)-H+ exchange with amiloride resulted in a slow acidification of rested fibres; resting pHi was not affected by either inhibition of HCO3(-)-Cl- exchange with DIDS (4,4'-diisothiocyanatostilbene-2,2'-disulphonic acid) or inhibition of the lactate transporter with cinnamate. 6. Fibres fatigued in cinnamate displayed a markedly larger acidification (approximately 0.4 pH units) and tension fell more rapidly than under control conditions; inhibition of Na(+)-H+ and HCO3(-)-Cl- exchange did not have any significant effect on fatigue. 7. The intracellular buffer power, assessed by exposing fibres to the weak base trimethylamine, was about 15 mM (pH unit)-1 in a HEPES-buffered solution (non-CO2 or intrinsic buffer power) and about 33 mM (pH unit)-1 in a bicarbonate-buffered solution. Somewhat higher values of the intrinsic buffer power was obtained from changes of the partial pressure of CO2 (PCO2) of the bath solution. Application of lactate or butyrate frequently gave an infinite buffer power, which indicates that powerful pH-regulating mechanisms operate in these cases.(ABSTRACT TRUNCATED AT 400 WORDS)
 ...
PMID:Changes of intracellular pH due to repetitive stimulation of single fibres from mouse skeletal muscle. 152 20

Internal fixation of comminuted unstable fractures of the severely osteoporotic proximal femur is sometimes supplemented with polymethyl-methacrylate (PMMA). We here report an in vitro biomechanical evaluation of a biodegradable particulate composite that might be used for similar purposes. The composite includes a matrix phase consisting of a hydrolyzable prepolymer [polypropylene fumarate (PPF)] cross-linked with methacrylate monomer, and a particulate phase consisting of tricalcium phosphate and calcium carbonate. We implanted dynamic hip screws in 22 cadaveric proximal femora and measured the yield load for an oblique force applied to the femoral head. The hip screws were then reinforced with either PMMA or the PPF composite and tested again. On the basis of analysis of variance, the average increases in yield load for PMMA and PPF reinforcement of 1,750 and 1,130 N were statistically significant (p less than 0.00005), suggesting that both materials enhance congruence between implant and bone and thereby increase the projected load-bearing area of the implant. The increase in yield force with PMMA was slightly higher than the increase with PPF (p less than 0.05), but both values after reinforcement were close (3,790 +/- 561 N for PMMA vs. 3,240 +/- 669 N for PPF). If we can demonstrate that appropriate rates of degradation, bony ingrowth, and static and fatigue properties can be achieved in vivo with this system, our data suggest that this PPF composite may have potential as an adjunct to the internal fixation of unstable fractures of the osteoporotic hip.
 ...
PMID:Biomechanical evaluation of a biodegradable composite as an adjunct to internal fixation of proximal femur fractures. 198 49

Mechanical ventilation in 75 out of 560 status asthmaticus episodes during a five-year period (1984-1988) at Chulalongkorn Hospital were analyzed. There were 58 patients with an average age of onset of first asthmatic attack of 18.5 years and an average age when requiring mechanical ventilation of 33 years, which is significantly younger than among those who did not require assisted ventilation. At the time of intubation, four patients were in sudden unexpected arrest and 19 patients were urgently ventilated because of respiratory muscle fatigue or carbon dioxide narcosis; the remaining 52 patients required elective mechanical ventilation. The arterial blood gas of 52 patients revealed a pH of 7.11 +/- 0.66, PaCO2 of 58.0 +/- 5.5 mmHg, and HCO3 of 15.0 +/- 5.8 mEg/L. Controlled mechanical ventilation was maintained for a mean of 38.68 hours. Fifty-one patients required intravenous diazepam (average dose = 24.3 mg) and 37 required morphine (average dose = 11.1 mg) for good syncronization in controlling mechanical ventilation. Pneumothorax was the most common complication with four, nine and one episodes occurring prior to, during and after assisted ventilation, respectively. Four, one and two patients developed the complications of pneumonia, atelectasis of the left lung due to mucous plugging and upper gastrointestinal hemorrhage, respectively. There were six patients who died of complications: four of brain anoxia, one of pneumothorax and another of unexplained cause.
 ...
PMID:Mechanical ventilation in status asthmaticus: experience with 75 episodes. 223 Jun 27

In an effort to determine the effects of bicarbonate (NaHCO3) ingestion on exercise performance, ten male college swimmers were studied during five different trials. Each trial consisted of five 91.4 m (100-yd) front crawl swims with a two-minute rest interval between each bout. The trials consisted of two NaHCO3 treatments, two placebo trials and one test with no-drink. One hour before the onset of swimming, the subjects were given 300 ml of citric acid flavored solution containing either 17 mmol of NaCl (placebo) or 2.9 mmol of NaHCO3.kg-1 body weight (experimental), or received no drink (no-drink). Performance times for each 91.4 m swim were recorded. Blood samples were obtained before and one hr after treatment, two min after warmup, and two min after the final 91.4 m sprint. Blood pH, lactate, standard bicarbonate (SBC) and base excess (BE) were measured. No differences were found for performance or the blood measurements between the placebo and no-drink trials. Bicarbonate feedings, on the other hand, produced a significant (P less than 0.05) improvement in performance on the fourth and fifth swimming sprints. Blood lactate, pH, SBC and BE were significantly higher (P less than 0.05) at post-exercise in NaHCO3 treatments. These data are in agreement with previous findings that during repeated bouts of exercise pre-exercise administration of NaHCO3 improves performance, possibly by facilitating the efflux of hydrogen ions from working muscles and thereby delaying the onset of fatigue.
 ...
PMID:Sodium bicarbonate ingestion improves performance in interval swimming. 284 39

The intracellular pH of frog sartorius muscles exposed to an extracellular pH 8.0 (25 mM HCO3-, 1% CO2) was 6.9-7.1. Following a fatiguing stimulation period (one tetanic contraction per second for 3 min), the intracellular pH was 6.5-6.7. When similar experiments were repeated with frog sartorius muscles exposed to pH 6.4 (2mM HCO3-, 1% CO2), the intracellular pH was 6.8-6.9 at rest and 6.3-6.4 following fatigue. So, in both experiments the intracellular pH decreased by 0.4-0.5 pH unit during fatigue. When the CO2 concentration of the bathing solution was increased from 1 to 30%, the intracellular pH of resting muscles decreased from 7.0 to 6.2-6.3. Although the effect of CO2 on the intracellular pH was greater than the fatigue effect, the decrease in tetanic force with CO2 was less than 40%, while during fatigue the tetanic force decreased by at least 70%. Therefore in frog sartorius muscle the decrease in tetanic force during fatigue exceeds the decrease that is expected from just a change in intracellular pH.
 ...
PMID:Is the change in intracellular pH during fatigue large enough to be the main cause of fatigue? 309 36

This single case study reports on a 74-year-old woman with 48-hour cycles of mood disturbance for 2 years. Every other day she awakened feeling sad with low energy, decreased appetite, fatigue, diminished enjoyment of normal activities, increased irritability, occasional self-deprecatory thoughts, and difficulty concentrating. On alternative days she was active, outgoing, energetic, and cheerful. Her past history was marked by mild postpartum depressions, not requiring treatment, with each of her six pregnancies, and a more severe depression at age 57, which seemed to respond to Premarin. During the recent 2-year period of mood swings, the patient was given trials of several heterocyclic antidepressant medications, but side effects precluded the use of therapeutic doses or durations of treatment. Reluctantly, the patient agreed to a trial of lithium carbonate. After the second week of lithium treatment, at a level of 0.4 mEq/ml, she reported marked improvement, feeling fine every day without mood fluctuations. After almost 1 year at this blood level, she remains asymptomatic. Thus, the patient's cyclic 48-hour unipolar depression responded dramatically and completely to low doses of lithium carbonate.
 ...
PMID:Cyclic 48-hour unipolar depression. 312 83

Depression is a major affective disorder characterized by feelings of loss, worthlessness, fatigue, and a general decrease in interest in the usual activities of daily living. This complex disorder is the most common mental health problem in the United States, more common in women, adults over 60 years of age, and those of lower socioeconomic status. According to the DSM III, the major subclassifications related to depression are major depression and bipolar disorder. An integrated causation theory is useful in describing the etiology of this disorder. Generally, signs and symptoms involve changes in affect, cognition, behavior, and physical functioning. Depression may be treated with antidepressant psychotropic medications (tricyclics and MAO inhibitors), lithium carbonate (for bipolar disorder), electroconvulsive therapy, and a variety of psychotherapies. Careful monitoring of the drugs via blood level values must be ongoing. Nursing care of hospitalized depressed persons involves careful monitoring of clients' status and the effectiveness of treatments. Nursing care focuses on three areas of need. Immediate needs are those related to critical and safety issues. Short-term needs are concerned with identifying and reducing or eliminating obvious problem areas which hamper return to community living. Long-term needs are issues related to maintenance of persons in the least depressive state for as long as possible. To provide a sound basis for planning and implementing such care, nurses must understand the dynamics of depression, the issues which dictate selected treatment methods, and the issues which are likely to shape and change the treatment of depression in the future. Nursing must accept the responsibility of acting in a responsible, professional manner to ensure the best possible treatment for clients within the restraints imposed by policy decisions.
 ...
PMID:Acute depression: treatment and nursing strategies for this affective disorder. 363 98

In order to determine the influence of two artificially induced alkalotic states on the ability to perform maximal exercise, six male subjects (mean age, 22.0 years; mean height, 176.8 cm; mean weight, 69.1 kg; mean VO2 max, 3.83 l min-1) were studied during three experimental trials. The subjects performed six 60-s cycling bouts, at a work rate corresponding to 125% VO2 max, with 60 s recovery between work bouts; these regimens were performed 1 h after the ingestion of a solution containing either; I, placebo; II, NaHCO3 in a dosage of 0.15 g per kg body weight; or III, NaHCO3 0.30 g per kg body weight. The sixth work bout was continued until the pedal velocity dropped below 50 rev min-1. Total work done for the entire work period was calculated. Blood samples were taken from a forearm vein prior to the exercise bouts for analysis of pH and HCO3. The results showed a significant pre-exercise difference in pH and HCO3 for all conditions (P less than 0.01). In conditions where artificial alkalosis had been achieved prior to exercise there was significant increase in the work produced: I, 121.6 kJ; II, 133.1 kJ; III, 133.5 kJ (P less than 0.05). The time to fatigue in the six bout was also significantly increased; I, 74.7 s; II, 111.0 s; III, 106.0 p (P less than 0.05). There were no significant differences between conditions II and III. Thus augmentation of the bicarbonate reserves has a significant positive effect on the energy metabolism in interval-type exercise, leading to an increase in the work done and in the time to fatigue.(ABSTRACT TRUNCATED AT 250 WORDS)
 ...
PMID:Maximal work production following two levels of artificially induced metabolic alkalosis. 373 82


1 2 3 4 5 6 Next >>