Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0432222 (SEM)
 47,337 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

To study the basis for the myasthenic illness that develops in some patients receiving D-penicillamine (D-P), we measured neuromuscular transmission in D-P-treated guinea pigs. Treated animals manifested edrophonium chloride-repairable decremental responses to 30-Hz nerve stimulation (8.5% +/- 1.5%--mean +/- SEM; N = 16) compared with the response in saline-treated control animals (-0.3% +/- 0.85%, N = 10, p less than 0.005). Posttetanic phenomena were studied in 5 treated animals; 3 revealed posttetanic exhaustion. Miniature endplate potential (MEPP) amplitudes were significantly reduced in 11 treated animals (0.612 +/- 0.016 mV) compared with 6 controls (0.713 +/- 0.024 mV, p less than 0.01). The MEPP frequency appeared reduced in treated animals. Both MEPP amplitude and MEEP frequency correlated with the decrement.
 ...
PMID:Penicillamine-induced myasthenic responses in the guinea pig. 22 88

The characteristics of the neuromuscular block produced by streptomycin in vivo were studied on the sciatic-tibialis anterior nerve-muscle preparation of eight anaesthetized cats. The lungs of the animals were ventilated mechanically and normocarbia was maintained. During acute exposure to streptomycin (within 2 h), ED50 for blockade of the twitch was 56 (SEM +/- 5) mg kg-1 of the base. The characteristics of block were similar to those of neomycin-induced block in some aspects. There was absence of train-of-four fade and tetanic fade, partial sparing of the responses elicited at 10 Hz and 20 Hz, and total sparing of the 50 Hz tetanus, as well as the post-tetanic twitch. In contrast to neomycin-induced neuromuscular block, however, post-tetanic exhaustion was not observed and prolonged exposure to streptomycin (22-28 h) did not change the characteristics of the block. We conclude that, despite their chemical similarities, streptomycin and neomycin block neuromuscular transmission differently.
 ...
PMID:Acute and subchronic neuromuscular blocking characteristics of streptomycin: a comparison with neomycin. 44 43

This study examined the effects of the Coenzyme Athletic Performance System (CAPS) on endurance performance to exhaustion. CAPS contains 100 mg coenzyme Q10, 500 mg cytochrome C, 100 mg inosine, and 200 IU vitamin E. Eleven highly trained male triathletes were given three daily doses of either CAPS or placebo (dicalcium phosphate) for two 4-week periods using a double-blind crossover design. A 4-week washout period separated the two treatment periods. An exhaustive performance test, consisting of 90 minutes of running on a treadmill (70% VO2max) followed by cycling (70% VO2max) until exhaustion, was conducted after each treatment period. The mean (+/- SEM) time to exhaustion for the subjects using CAPS (223 +/- 17 min) was not significantly different (p = 0.57) from the placebo trial (215 +/- 9 min). Blood glucose, lactate, and free fatty acid concentrations at exhaustion did not differ between treatments (p < 0.05). CAPS had no apparent benefit on exercise to exhaustion.
 ...
PMID:Effects of coenzyme athletic performance system as an ergogenic aid on endurance performance to exhaustion. 133 84

To investigate the effect of endurance training on physiological characteristics during circumpubertal growth, eight young runners (mean starting age 12 years) were studied every 6 months for 8 years. Four other boys served as untrained controls. Oxygen uptake (VO2) and blood lactate concentrations were measured during submaximal and maximal treadmill running. The data were aligned with each individual's age of peak height velocity. The maximal oxygen uptake (VO2max; ml.kg-1.min-1) decreased with growth in the untrained group but remained almost constant in the training group. The oxygen cost of running at 15 km.h-1 (VO2 15, ml.kg-1.min-1) was persistently lower in the trained group but decreased similarly with age in both groups. The development of VO2max and VO2 15 (l.min-1) was related to each individual's increase in body mass so that power functions were obtained. The mean body mass scaling factor was 0.78 (SEM 0.07) and 1.01 (SEM 0.04) for VO2max and 0.75 (SEM 0.09) and 0.75 (SEM 0.02) for VO2 15 in the untrained and trained groups, respectively. Therefore, expressed as ml.kg-0.75.min-1, VO2 15 was unchanged in both groups and VO2max increased only in the trained group. The running velocity corresponding to 4 mmol.l-1 of blood lactate (nu la4) increased only in the trained group. Blood lactate concentration at exhaustion remained constant in both groups over the years studied. In conclusion, recent and the present findings would suggest that changes in the oxygen cost of running and VO2max (ml.kg-1.min-1) during growth may mainly be due to an overestimation of the body mass dependency of VO2 during running.(ABSTRACT TRUNCATED AT 250 WORDS)
 ...
PMID:Oxygen uptake during running as related to body mass in circumpubertal boys: a longitudinal study. 139 39

To study the physiological response to heavy training, seven male competitive cyclists intensified their normal training program for two weeks (IIT) in order to achieve a state of short-term overtraining. The subjects underwent a graded cycle ergometer test to exhaustion, an outdoor 8.5 km time trial and a computerized test to study reaction time and visual perception, before, during and after the two weeks of intensified training and after two weeks of recovery. Furthermore subjects kept a daily log in the form of a questionnaire. After two weeks of IIT all subjects showed symptoms of overtraining: the general state of well being declined as indicated by the questionnaire while performances on time trial (mean +/- SEM: 830 +/- 14 sec-871 +/- 19 sec), contests and maximal power output (mean +/- SEM: 336 7 watt-310 +/- 5 watt) declined significantly. Maximal (mean +/- SEM 11.8 +/- 1.1 mmol.l-1-5.9 +/- 0.5 mmol.l-1) and submaximal lactate values were significantly lowered during ergometer test after the IIT, while the workload at the 4 mmol point increased significantly (mean +/- SEM 234 +/- 10 watt-267 +/- 13 watt). Sleeping heart rate increased significantly (mean +/- SEM 49.5 +/- 9.3 BPM-54.3 +/- 8.8 BPM). Maximal heart rate (mean +/- SEM 185 +/- 3 BPM-178 +/- 2 BPM, mean heart rate during the time trial (mean +/- SEM 178 +/- 2 BPM-169 +/- 2 BPM) and VO2max (mean +/- SEM 4801 +/- 121 ml.min-1-4409 +/- 101 ml.min-1) were all significantly lowered by the IIT.(ABSTRACT TRUNCATED AT 250 WORDS)
 ...
PMID:Physiological changes in male competitive cyclists after two weeks of intensified training. 145 49

This study examined the effect of exposure of the whole body to moderate cold on blood lactate produced during incremental exercise. Nine subjects were tested in a climatic chamber, the room temperature being controlled either at 30 degrees C or at 10 degrees C. The protocol consisted of exercise increasing in intensity in 35 W increments every 3 min until exhaustion. Oxygen consumption (VO2) was measured during the last minute of each exercise intensity. Blood samples were collected at rest and at exhaustion for the measurement of blood glucose, free fatty acid (FFA), noradrenaline (NA) and adrenaline (A) concentrations and, during the last 15 s of each exercise intensity, for the determination of blood lactate concentration [la-]b. The VO2 was identical under both environments. At 10 degrees C, as compared to 30 degrees C, the lactate anaerobic threshold (Than,la-) occurred at an exercise intensity 15 W higher and [la-]b was lower for submaximal intensities above the Than,la-. Regardless of ambient temperature, glycaemia, A and NA concentrations were higher at exhaustion while FFA was unchanged. At exhaustion the NA concentration was greater at 10 degrees C [15.60 (SEM 3.15) nmol.l-1] than at 30 degrees C [8.64 (SEM 2.37) nmol.l-1]. We concluded that exposure to moderate cold influences the blood lactate produced during incremental exercise. These results suggested that vasoconstriction was partly responsible for the lower [la-]b observed for submaximal high intensities during severe cold exposure.
 ...
PMID:Influence of moderate cold exposure on blood lactate during incremental exercise. 156 66

The effects of muscle contraction frequency on blood flow to the calf muscle (Qcalf) were studied in six female subjects, who performed dynamic plantar flexions at frequencies of 20, 40, 60, 80 and 100 contractions.min-1, in a supine position. The Qcalf measured by a mercury-in-rubber strain gauge plethysmograph, increased as contraction frequency increased and reached a peak at 60-80 contractions.min-1. After 100 plantar flexions at 60 contractions.min-1, the mean Qcalf was 30.95 (SEM 4.52) ml.100 ml-1.min-1. At 100 contractions.min-1, however, it decreased significantly compared with that at 60 contractions.min-1 at a specified time (2 min or exhaustion) or after a fixed amount of work (100 contractions). The contraction frequency at which Qcalf reached a peak depended on the duration of exercise. The heart rate showed its highest mean value at 60 contractions.min-1 and decreased significantly at 100 contractions.min-1. The mean blood pressure was lower at 100 contractions.min-1 than at 60 contractions.min-1. The relaxation period between contractions, measured by recording the electromyogram from the gastrocnemius muscles, shortened markedly as the frequency increased; the mean value at 100 contractions.min-1 was 0.14 (SEM 0.02) s, which corresponded to 35.7% of the contraction time. This shortened relaxation period between contractions should have led to the inhibition of exercise hyperaemia at the higher contraction frequencies.
 ...
PMID:Reduced exercise hyperaemia in claf muscles working at high contraction frequencies. 159 53

To determine whether exercise-induced increases in tissue plasminogen activator (t-PA) were related to plasma epinephrine concentration during exercise, 14 healthy men (aged 24 to 62 years) were studied during epinephrine infusions (10, 25 and 50 ng/kg per min) and graded supine bicycle exercise, beginning at 33 W and increasing in 33-W increments until exhaustion. Plasma epinephrine, active and total t-PA, active plasminogen activator inhibitor type 1 (PAI-1) and t-PA/PAI-1 complex concentrations were measured at each exercise and infusion level. During epinephrine infusion, active and total t-PA levels increased linearly with the plasma epinephrine concentration (respective slopes [+/- SEM] of 0.062 +/- 0.003 and 0.076 +/- 0.003 pmol/ng epinephrine). During exercise, t-PA levels did not increase until plasma epinephrine levels increased, after which both active and total t-PA levels again increased linearly with the plasma epinephrine concentration, but at twice the rate observed with epinephrine infusion (0.131 +/- 0.005 and 0.147 +/- 0.005 pmol/ng, respectively). The t-PA level in blood was directly proportional to the plasma epinephrine concentration during both exercise and epinephrine infusion, suggesting that epinephrine release during exercise stimulates t-PA secretion. In these healthy subjects, active plasminogen activator inhibitor type 1 and t-PA/PAI-1 complex levels were low (41 +/- 11 and 21 +/- 5 pmol/liter, respectively) and did not change significantly during exercise or epinephrine infusion. It is concluded that approximately 50% of the increase in t-PA during exercise is due to stimulated release of t-PA by epinephrine.(ABSTRACT TRUNCATED AT 250 WORDS)
 ...
PMID:Fibrinolytic response during exercise and epinephrine infusion in the same subjects. 159 33

We investigated whether fatigue of the expiratory muscle, that is, the abdominal muscle, may account for a change in the respiratory effort sensation in normal subjects during expiratory threshold loading. The respiratory effort sensation was scored using a modified Borg scale. Expiratory muscle fatigue was assessed both from changes in the maximal static expiratory pressure and in the centroid frequency (fc) of the abdominal muscle electromyogram (EMG). Expiratory threshold loading (magnitude of threshold; 40 to 60% of the maximal expiratory pressure at FRC, breathing frequency = 15/min, and duty cycle = 0.5) was continued until exhaustion or for 30 min. Loading was repeated following a 15-min recovery period after the end of the first expiratory loading. The maximal static expiratory pressure during loading (Pmmax) decreased initially and then remained decreased. Decreases were smaller with the 40% load (22 +/- 6%, SEM) than with the 60% load (37 +/- 3%) (p less than 0.05). The decrease during the second run of the 60% load was greater than during the first (p less than 0.01 by ANOVA). The maximal expiratory pressure at TLC before the second run of the 60% load was decreased by 9 +/- 3% compared with the control (p less than 0.02) but that with the 40% load was not. The fc with the 60% load decreased initially by 8 +/- 1% and then remained constant, although no change was observed with the 40% load.(ABSTRACT TRUNCATED AT 250 WORDS)
 ...
PMID:Relationship of respiratory effort sensation to expiratory muscle fatigue during expiratory threshold loading. 173 58

Growth hormone (GH) response to standardized exercise, L-DOPA/propranolol and a 6-h diurnal GH profile (GHP) were evaluated in twenty-three children with very short stature and abnormal growth velocities. Standardized exercise (Jones Stage I) was performed on a cycle ergometer at 53% of the maximum oxygen consumption (VO2max) for 20 min. VO2max was determined by an incremental progressive workload until exhaustion. The mean +/- SEM peak GH concentration (ng/ml) for each test was: exercise, 8.7 +/- 1.3; L-DOPA/P: 12.8 +/- 1.9 and GHP: 3 +/- 0.7. There was no statistical difference between exercise and L-DOPA/P peaks but both peaks were significantly higher than the peak observed during the profile. During exercise 14 of 23 patients had a GH response greater than 8 ng/ml. Two patients were found to be GH deficient. Therefore 16 of 23 patients (86%) had a result concordant with their final diagnosis. During the L-DOPA/P test 17 of 23 patients had a GH response greater than 8 ng/ml. By contrast only 6 of 23 patients had a positive response during GHP. Standardized exercise is as effective as L-DOPA/P as a stimulation test for growth hormone response in very short children with abnormal growth velocities. Exercise has the advantages of being physiological, having minimal side effects, and requiring fewer blood samples. In this population of children, exercise and L-DOPA/propranolol are significantly better than the 6-h growth hormone profile for assessing GH secretion.
 ...
PMID:Growth hormone response in very short children. 178 31


1 2 3 4 5 6 7 8 9 10 Next >>