Muscle glycogen accumulation after endurance exercise in trained and untrained individuals

Muscle glycogen accumulation was determined in six trained cyclists (Trn) and six untrained subjects (UT) at 6 and either 48 or 72 h after 2 h of cycling exercise at approximately 75% peak O2 uptake (VO2 peak), which terminated with five 1-min sprints. Subjects ate 10 g carbohydrate . kg-1 . day-1 for 48-72 h postexercise. Muscle glycogen accumulation averaged 71 +/- 9 (SE) mmol/kg (Trn) and 31 +/- 9 mmol/kg (UT) during the first 6 h postexercise (P < 0.01) and 79 +/- 22 mmol/kg (Trn) and 60 +/- 9 mmol/kg (UT) between 6 and 48 or 72 h postexercise (not significant). Muscle glycogen concentration was 164 +/- 21 mmol/kg (Trn) and 99 +/- 16 mmol/kg (UT) 48-72 h postexercise (P < 0.05). Muscle GLUT-4 content immediately postexercise was threefold higher in Trn than in UT (P < 0.05) and correlated with glycogen accumulation rates (r = 0.66, P < 0.05). Glycogen synthase in the active I form was 2.5 +/- 0.5, 3.3 +/- 0.5, and 1.0 +/- 0.3 micromol . g-1 . min-1 in Trn at 0, 6, and 48 or 72 h postexercise, respectively; corresponding values were 1.2 +/- 0.3, 2.7 +/- 0.5, and 1.6 +/- 0.3 micromol . g-1 . min-1 in UT (P < 0.05 at 0 h). Plasma insulin and plasma C-peptide area under the curve were lower in Trn than in UT over the first 6 h postexercise (P < 0.05). Plasma creatine kinase concentrations were 125 +/- 25 IU/l (Trn) and 91 +/- 9 IU/l (UT) preexercise and 112 +/- 14 IU/l (Trn) and 144 +/- 22 IU/l (UT; P < 0.05 vs. preexercise) at 48-72 h postexercise (normal: 30-200 IU/l). We conclude that endurance exercise training results in an increased ability to accumulate muscle glycogen after exercise.     

Bone density and cyclic ovarian function in trained runners and active controls

This study was conducted to determine whether rigorous exercise training adversely affects ovarian hormone levels and bone health in cyclically menstruating trained runners. Ovarian hormones, bone mineral density (BMD), body composition, 3-d diet records, 3-d estimated energy expenditure, and menstrual histories were evaluated in 10 trained collegiate runners and 10 moderately active controls. The trained runners had lower total body calcium per kg of soft lean tissue measured by DEXA (P = 0.045). Half of the trained runners had experienced stress fractures compared with only one of the moderately active controls. The trained runners' lumbar (L2-L4) BMD (1.178 g.cm-2) was not significantly different from that of the active controls (1.283 g.cm-2) (P = 0.074) but, for all subjects combined, there wasa significant inverse relation between L2-L4 BMD and distance run per week (P = 0.036). Further, adding age, body weight, percent body fat, daily energy intake, and daily calcium intake to a stepwise multiple regression analysis did not significantly improve predictive precision. The trained runners consumed nearly twice the amount of calcium (1089 mg.d-1 vs 641 mg.d-1, respectively; P = 0.036), while intake of other nutrients did not differ significantly between groups. Urinary estrone conjugates (E1C) were lower in the trained runners during the early follicular phase (P = 0.028), while pregnanediol-3-glucuronide (PdG) was not significantly different between groups during the luteal phase (P = 0.213). Thus, it appears that lower estrogen production, especially during the early follicular phase, and not progesterone, is associated with lower whole body calcium per kg of soft lean tissue and, probably, L2-L4 BMD. Results of this study also suggest that regular menstrual cycles do not imply normal ovarian hormone function in young women who are engaged in either recreational or competitive running.     

Influence of a Biokinergia session on cardiorespiratory and metabolic adaptations of trained subjects

Infusion pumps are used to deliver drugs and other substances to patients at a pre-set rate. Infusion pumps are classified according to their application, whether ambulatory, patient controlled, anaesthesia or general purpose units.     

Left ventricular function during dynamic exercise in untrained and moderately trained subjects

The influence of exercise training on left ventricular function at rest (R), at anaerobic threshold (AT), and during peak exercise (PE) was evaluated in 12 healthy untrained and 13 trained (T) subjects who underwent Doppler echocardiography at R and radionuclide ventriculography at R and during exercise. The end-diastolic volume and stroke volume were significantly higher in the T group than in the untrained group at R. The ejection fraction rose significantly from R to AT and from AT to PE (80.0 +/- 0.84 vs. 83.6 +/- 0.91%), but no significant difference was observed between groups. The peak diastolic filling rate rose significantly during exercise, with a further significant increase observed in the T group (AT, 6.38 +/- 0.40 vs. 5.01 +/- 0.16 end-diastolic counts/s; PE, 8.24 +/- 0.42 vs. 7.15 +/- 0.35 end-diastolic counts/s). The percent variation of minimal systolic counts fell significantly at AT and PE in relation to R. Our data demonstrate that exercise training produces a significant increase in peak diastolic filling rate but no change in systolic function during exercise and that metabolic acidosis caused by exercise does not limit systolic function.     

Chronotropic competence in endurance trained heart transplant recipients: heart rate is not a limiting factor for exercise capacity

Soy isoflavones are hypothesized to be responsible for changes in hormone action associated with reduced breast cancer risk. To test this hypothesis, we studied the effects of isoflavone consumption in 14 premenopausal women. Isoflavones were consumed in soy protein powders and provided relative to body weight (control diet, 10 +/- 1.1; low isoflavone diet, 64 +/- 9.2; high isoflavone diet, 128 +/- 16 mg/day) for three menstrual cycles plus 9 days in a randomized cross-over design. During the last 6 weeks of each diet period, plasma was collected every other day for analysis of estrogens, progesterone, LH, and FSH. Diet effects were assessed during each of four distinctly defined menstrual cycle phases. Plasma from the early follicular phase was analyzed for androgens, cortisol, thyroid hormones, insulin, PRL, and sex hormone-binding globulin. The low isoflavone diet decreased LH (P = 0.009) and FSH (P = 0.04) levels during the periovulatory phase. The high isoflavone diet decreased free T3 (P = 0.02) and dehydroepiandrosterone sulfate (P = 0.02) levels during the early follicular phase and estrone levels during the midfollicular phase (P = 0.02). No other significant changes were observed in hormone concentrations or in the length of the menstrual cycle, follicular phase, or luteal phase. Endometrial biopsies performed in the luteal phase of cycle 3 of each diet period revealed no effect of isoflavone consumption on histological dating. These data suggest that effects on plasma hormones and the menstrual cycle are not likely to be the primary mechanisms by which isoflavones may prevent cancer in premenopausal women.     

Interrater reliability of six tests of trunk muscle function and endurance

Some studies have shown a relationship between trunk muscle strength and low back pain. Measures of trunk muscle strength and endurance, which are feasible in the clinical setting, are needed. The purpose of this study was to determine interrater reliability of six tests of abdominal and trunk extensor muscle strength and endurance. The tests included abdominal and extensor dynamic endurance, hand-held dynamometry of isometric flexion and extension, and abdominal and extensor static endurance. Thirty-nine healthy workers were recruited as subjects. Each was tested by three raters on 3 days within 1 week. Intraclass correlation coefficients (ICC) and the standard error of measurement (SEM) were calculated: abdominal dynamic endurance ICC = .89, SEM = 8 repetitions; extensor dynamic endurance ICC = .78, SEM = 9 repetitions; abdominal isometric force ICC = .25, SEM = 60 N; extensor isometric force ICC = .24, SEM = 68 N; abdominal static endurance ICC = .51, SEM = 35 seconds; extensor static endurance ICC = .59, SEM = 20 seconds. The dynamic endurance tests had acceptable interrater reliability. For the others, reliability was poor and the SEMs were large.     

Effect of training on some metabolic changes associated with submaximal endurance exercise in the horse

The effects of prolonged cantering before and after a 10 week training programme were studied in 6 horses. Determinations were carried on on venous blood for packed cell volume, glucose, glycerol, free fatty acids, beta-hydroxybutyrate, 11-hydroxycorticosteroids, pH and pCO2. Exercise caused a slight increase in glucose, lactate and pH, a moderate rise in PCV, glycerol and free fatty acids, and a marked rise in 11-hydroxycorticosteroids. A decrease in venous pCO2 occurred and a slight but not significant decrease in beta-hydroxybutyrate. Training was found to cause no significant difference in the changes seen. However, there was a tendency for exercise to result in higher 11-hydroxycorticosteroid levels after training.     

Coronary collateral circulation behaviour and myocardial viability in chronic total occlusion treated with coronary angioplasty

AIMS: We explored the role of microcirculation integrity following the chronic occlusion of an infarct-related artery to assess the behaviour of collateral circulation during and after reperfusion by coronary angioplasty METHODS AND RESULTS: Eighteen patients with a proximally occluded left anterior descending artery and firm evidence of intercoronary collateral circulation were studied with selective coronary angiography and selective intracoronary myocardial contrast echocardiography, before coronary angioplasty, and at 5 and 15 min and 12 h later. Myocardial enhancement during myocardial contrast echocardiography was evaluated with a semiquantitative score (0-3), which was correlated to basal and 6 months' regional left ventricular wall motion results. 16/18 procedures were successfully performed; four patients with an inadequate acoustic window were excluded. Restenosis was evident at the 6 months' follow-up in two patients. Basal myocardial contrast echocardiography indicated that 81/192 segments from the left anterior descending coronary artery and 90/192 from the right coronary artery were perfused; no perfusion was observed in 21 segments either before or after coronary angioplasty. After coronary angioplasty, the angiographic intercoronary collateral circulation immediately disappeared, and myocardial contrast echocardiography revealed that there was a progressive reduction of segments perfused by the right coronary artery and an increase in segments perfused by the left anterior descending coronary artery. Regional left ventricular wall motion analysis demonstrated that there was abnormal motion in 51/192 segments. There was no improvement in segments with score 0 and abnormal motion after 6 months (100% sensitivity), but 16/17 segments with score 3 did show an improvement (98% specificity). The predictive value of intermediate scores (1-2) in detecting long-term improvement, was only 43%. CONCLUSION: These data show that the adaptive mechanism observed in the behaviour of epicardial and microvascular circulation after reperfusion of a chronic occluded infarct-related artery can vary. In addition, this study clearly shows that microvascular integrity detected by myocardial contrast echocardiography can provide myocardial viability.     

Peripheral circulation regulation in patients with the neuroendocrine metabolic form of hypothalamic syndrome

Peripheral circulation and regulating hormonal (renin-angiotensin-aldosterone system) and electrolytic (plasma sodium and potassium) factors were studied in 102 patients with the hypothalamic syndrome neuroendocrine metabolic form administered pathogenetic therapy with antiserotonin and dopaminergic drugs as well as routine therapy. Blood plasma sodium vasopressin and aldosterone levels were found increased, arterial vessel reactivity in the forearm reduced, and venous circulation disordered in these patients. Routine therapy failed to normalize electrolytes and hormonal parameters and was conducive to a still more marked reduction of arterial vessel reactivity. Peritol therapy resulted in a reduction of vasopressin concentration and normalization of blood plasma sodium and aldosterone, as well as in improvement of the myogenic mechanisms of vascular tone regulation and normalization of venous circulation parameters. A course of parlodel therapy lead to normalization of blood plasma levels of vasopressin, aldosterone, and sodium but no changes in the regional vessels were observed.     

Dissociation of changes in metabolic rate and blood pressure with erythrocyte Na-K pump activity in older men after endurance training

We examined whether changes in resting metabolic rate (RMR) and blood pressure in older normotensive men in response to endurance training were associated with alterations in the Na-K pump activity of plasma-bathed erythrocytes. Eleven men performed cycling exercise three times a week for 8 weeks, and six other men served as controls. Measurements included: RMR by indirect calorimetry, supine blood pressure, body composition by underwater weighing, plasma and erythrocyte Na and K parameters using flame photometry and ouabain. Peak VO2 increased 12% (p < .001), RMR increased 10% (p < .01), mean blood pressure decreased 5% (p < .05), erythrocyte K increased 5% (p < .01), plasma K decreased 7% (p < .001), and plasma Na decreased by 4% (p < .001) in response to training. Erythrocyte Na and Na-K pump rate did not change, nor did the individual changes correlate with changes in RMR or mean blood pressure. Exercise training increases RMR and reduces blood pressure in older men, but these changes are dissociated with erythrocyte Na-K pump activity.     

Coronary venous arterialization: acute hemodynamic, metabolic, and chronic anatomical observations

Power-spectrum analysis of the electroencephalogram and inhaled-exhaled concentrations of halothane (when used), nitrous oxide, and carbon dioxide of 36 patients during surgical operations under general anesthesia were monitored. Electroencephalographic arousal reactions were detected in 24 patients and these were accompanied by irregular respirations in nine patients. Cardiac arrhythmias occurred following an arousal reaction in eight patients. The authors conclude that this electroencephalographic arousal phenomenon occurs frequently and deserves further investigation to define its clinical implications and how it might be avoided.     

Simulation of metabolic processes in human circulation: evaluation of pH value and CO2 balance

This article describes a model of the human circulatory system, with emphasis on metabolic processes in particular the calculation of CO2 balance and the pH of venous blood. The model overall is capable of simulating both physiological and pathological circulatory systems. Simulated parameters are locally distributed blood flows, and pressures in the arterial system. This modelling of haemodynamics serves, among other things, to determine the oxygen supply situation of individual organs. The four most important control mechanisms of the human circulatory system for maintaining haemodynamics--the renin-angiotensin system, the autonomic nervous system, local arterial autoregulation and vascular stress relaxation--have been incorporated into the model. Another important parameter for estimating the oxygen supply situation of the human body is the acid-base status of arterial and venous blood. The calculation of the pH of blood plasma and erythrocytes is described in the second part of the article. The results achieved with our simulation model correspond well with those reported in the literature. The behaviour of the human circulatory system can be reproduced at rest and under conditions of loading.     

Physiological, metabolic and biochemical responses of horses competing in the speed and endurance phase of a CCI*****3-day-event

The present study was undertaken to investigate physiological, metabolic, haematological and biochemical changes in horses competing in the Speed and Endurance test of a Concours Complet International (CCI)*****3-day-event held under FEI rules. A total of 28 horses competing in the Burghley Horse Trials Speed and Endurance test were selected to be monitored: 11 horses in 1993 and 17 horses in 1994. Of the 28 horses selected, 17 completed the Speed and Endurance test and went on to complete the showjumping test. Mean +/- s.d. shade temperature and relative humidity, black globe temperature and wind speed were 13 +/- 1 and 20 +/- 2 degrees C, 54 +/- 3 and 55 +/- 10%, 17 +/- 2 and 29 +/- 4 degrees C and 2.7 +/- 0.7 and 1.2 +/- 0.3 m/s, for 1993 and 1994, respectively. Mean heart rate during Phases A, B and D was not significantly different between years, but mean heart rate during Phase C and X was significantly higher in 1994. Mean (+/- s.d.) heart rate on Phase B and D for all horses in both 1993 and 1994 was 198 +/- 8 and 188 +/- 11 beats/min, respectively. Mean heart rate during Phase D showed a poor correlation with mean speed (r = 0.412). Total mean (+/- s.d.) weight loss from the start of Phase A to the end of Phase D was 15.5 +/- 6.1 kg in 1993 and 16.5 +/- 5 kg in 1994 and did not differ significantly between years. Following 14-18 h completion of Phase D, mean bodyweight was not significantly different from that at the start of Phase A in either year. Mean rectal temperature at the end of Phase D was 41 +/- 0.6 degrees C and 41.1 +/- 0.6 degrees C in 1993 and 1994, respectively (P > 0.05). Both the lowest (39.7 degrees C) and highest (41.8 degrees C) rectal temperatures were recorded at the end of Phase D in 1994. Plasma lactate concentrations at the end of Phase D were 8.5-38.5 mmol/l. The highest lactate concentration also coincided with the highest plasma glucose concentration (11.4 mmol/l) as well as the joint fastest time in either year, although overall lactate showed only weak correlations with mean speed on Phase D (r = 0.12, 1993; r = 0.58, 1994). While the Speed and Endurance test at CCI*****level run in a temperate climate presents a considerable challenge to the fitness and ability of the horses competing, the metabolic and physiological changes are not extreme. The majority of horses that finish the test appear to undergo a rapid and considerable degree of recovery and are able to present sound at the final inspection, take part in the showjumping test and complete the competition.     

The acute reversal of a diet-induced metabolic acidosis does not restore endurance capacity during high-intensity exercise in man

The present experiment was designed to investigate whether a diet-induced metabolic acidosis was a major factor in the earlier onset of fatigue during high-intensity exercise. Six healthy males cycled to exhaustion at a workload equivalent to 95 percent of maximum oxygen uptake on four separate occasions. Exercise tests were performed after an overnight fast and each test was preceded by one of four experimental conditions. Two experimental diets were designed, either to replicate each subject's own normal diet [N diet, mean (SD) daily energy intake (E) = 13 (0.7) MJ, 14.5 (0.8) percent protein (Pro), 37.5 (2.2) percent fat (Fat) and 47.5 (2.1) percent carbohydrate (CHO)], or a low-carbohydrate diet [E = 12.6 (0.8) MJ, 33.6 (1.3) percent Pro, 64.4 (1.5) percent Fat and 2.2 (0.4) percent CHO]. These diets were prepared and consumed within the department over a 3-day period. Over a 3-period prior to the exercise trial subjects ingested either NaHCO(3) or CaCO(3) (3.6 and 3.0 mmol*kg body mass), thus giving four experimental conditions: N diet and treatment, N diet and placebo, low-CHO diet and treatment and low-CHO diet and placebo. Treatments were assigned using a randomised protocol. Arterialised venous blood samples were taken for the determination of acid-base status and metabolite concentrations at rest prior to exercise and at intervals for 30 min following exhaustion. Consumption of the low-CHO diet induced a mild metabolic acidosis which was reversed by the ingestion of NaHCO(3). Blood pH, bicarbonate (HCO-(3)) and base excess (BE) were higher following NaHCO(3) ingestion after the normal diet than all of the other experimental conditions (P <0.01). Exercise time following the low-CHO diet was less than on the normal diet conditions (P <0.05): bicarbonate ingestion had no effect on exercise time on either of the diet conditions. Post-exercise blood pH, HCO-(3); and BE were higher following the ingestion of NaHCO(3) irrespective of the pre-exercise diet (P <0.05). Blood lactate concentration was higher 2 min after exercise following the N diet with NaHCO(3) when compared to the low-CHO diets with either NaHCO(3) or placebo (P <0.05). Plasma ammonia accumulation was not significantly different between experimental conditions. These data confirm previous data showing that the ingestion of a low-CHO diet reduces the capacity to perform high-intensity exercise, but it appears that the metabolic acidosis induced by the low-CHO diet is not the cause of the reduced exercise capacity observed during high-intensity exercise under these conditions.     

Coronary surgery without extracorporeal circulation. Indications, methods and results. Apropos of 224 cases

Coronary revascularization without cardiopulmonary bypass is evolving as an important technique. From January 1988 to September 1997, 224 patients underwent consecutively coronary artery bypass grafting without cardiopulmonary bypass in our institution. Indications for this type of revascularization were essentially: patients with a single coronary lesion and patients which presented an increased risk for extra-corporeal circulation. Follow-up was complete. The majority of patients were men (176) and the median age was 62 years. Most patients were in CCS III and IV (79%). Unstable angina was found in 19%, 4% had a recent trans mural infarction (< or = 48 hr), and 36% had an older infarct (> 48 hr). 8% were operated in emergency, 29% presented a restenosis following angioplasty, with 4% having a complication from angioplasty, and 0.8% were operated in cardiogenic shock. Redo surgery was seen in 4% of patients. 12% of patients had an ejection fraction less than 30%, 47% an ejection fraction between 30 et 49%, and 40% patients an ejection fraction greater than 50%. Mean Parsonnet score was 10. 185 patients (82.5%) underwent single bypass, and 39 patients (17%) multiple bypasses. Ten patients (4.4%) underwent hybrid revascularization with primarily surgical grafting followed by angioplasty. Postoperative outcome included: myocardial infarction in 16 patients (7.1%), 8 patients (3.5%) were reoperated for tamponade or bleeding, 2 patients (0.8%) developed a mediastinitis, and 1 patient (0.4%) had a neurological event. Hospital mortality was 4% (9 patients). Univariate and multivariate analysis identified two risks factors: age greater than 70 (OR 4.2, CI 1-18.4), and an ejection fraction less than 30% (OR 5, CI 1.2-21.6). Survival was 99.1% at 1 year, 94% at 3 years and 83.2% at 7 years. Post operative angina occurred in 33 patients, linked to a coronary anastomosis dysfunction in 9 patients (4.1%). A significant reduction of cost was found, compared to patients operated with extra-corporeal circulation. We conclude that coronary revascularization without cardiopulmonary bypass can provide satisfactory results, for patients with single coronary lesion, or for patients with an increased risk and multiple coronary lesions.     

Coronary artery bypass grafting in cases with poor left ventricular function

From January 1987 through June 1992, 18 patients with poor left ventricular function (left ventricular ejection fraction [LVEF] less than 0.3) underwent elective isolated primary coronary artery bypass surgery. The mean age was 56.4 years (range, 46 to 72 years), and 15 were males and 3 were females. Mean pre-operative LVEF measured by ventriculography was 0.26 +/- 0.03 (range, 0.19 to 0.30). Sixteen patients (88.9%) had a prior myocardial infarction and 9 (50%) had a history of congestive heart failure. Complete revascularization was the goal for all patients, and the mean number of bypass grafts was 3.0 +/- 0.8 per patient. The left anterior descending coronary artery (LAD) was revascularized in all patients. There were no operative deaths. Post-operative LVEF improved significantly from 0.26 +/- 0.03 to 0.42 +/- 0.11 (p = 0.0002), and the regional left ventricular wall motion improved in the diaphragmatic and posterobasal regions (p < 0.01). The patency of the grafts was 93.9% in all, and 100% for LAD. The mean follow-up period was 77 months, and the overall actuarial survival rate was 88.9% at 10 years. During follow-up periods, two patients died of congestive heart failure (CHF), and two required three rehospitalizations because of CHF. The overall cardiac event free rate was 75.8% at 10 years. In patients with poor left ventricular function, surgical revascularization can be performed safely, but congestive heart failure sometimes occurs during follow-up periods and may be the cause of death. Therefore alternate forms of therapy such as cardiac transplantation and/or TMLR should be considered in selected patients.     

Coronary heart disease moderates the relationship of chronic stress with the metabolic syndrome

Mutations have been identified in the beta2-microglobulin gene of tumor cells of two metastatic melanoma patients who received immunizations with MAGE peptides. One mutation abolishes the start codon whereas the other introduces a premature stop codon. The second beta2-microglobulin allele of both tumors appears to be lost on the basis of sequence data and loss of microsatellite heterozygosity. The lack of beta2-microglobulin gene product results in the absence of HLA class I antigens on the surface of the tumor cells. This may explain why the tumors of both patients progressed despite the immunization treatment and shows the necessity of analyzing in depth the antigen presentation capability of the tumor cells for the interpretation of clinical trials involving anti-tumor vaccination.