The effects of prolonged physical exercise on renal function, electrolyte balance and muscle cell breakdown.

BACKGROUND: Postexercise proteinuria, hematuria and changes in serum electrolyte balance as well as increased levels of plasma indicators for muscle leakage are believed to be transient and of benign character. METHODS: A group of 51 healthy athletes took part in a 100 km race over 14.25 hours. All of them had to reach the finish together. Urine and blood samples were collected before (a) and immediately after running (b) as well as 6 hours after the race (c). RESULTS: The serum concentrations of potassium (4.8 +/- 0.5 (a) vs. 4.0 +/- 0.3 (c) mmol/l), protein (73.1 +/- 5.2 (a) vs. 71.1 +/- 3.9 (c) g/l) and albumin (44.0 +/- 2.85 (a) vs. 42.9 +/- 2.8 (c) g/l) decreased significantly (p < 0.0001, p < 0.05, p < 0.05, respectively) but remained within physiological ranges. The serum sodium concentration decreased immediately after the race (136.9 +/- 4.5 (a) vs. 131.1 +/- 2.4 (b) micromol/l, p < 0.0001). The fractional sodium excretion decreased 6 hours, but not immediately after the race (0.78 +/- 0.59 (a) vs. 0.48 +/- 0.82 (c), p < 0.05). Myoglobin (31.8 +/- 6.9 (a), 291.5 +/- 197.2 (b) and 182.2 +/- 135.3 (c) microg/l, p < 0.0001) and creatine kinase (1.13 +/- 0.45 (a), 10.76 +/- 6.9 (b) and 9.46 +/- 15.5 (c) pmol/l, p < 0.0001) increased dramatically. Troponin I was also significantly increased at finish (0.0186 +/- 0.0121 (a) vs. 0.0213 +/- 0.0165 (b) ng/ml, p < 0.05) and positively correlated with myoglobin and creatine kinase, but remained far below the pathologic range. Serum creatinine and urea remained almost unchanged. Glucosuria and hematuria occurred 6 hours after the run in 9.1% and 6.8%, respectively. The erythrocytes examined by phase-contrast microscopy were not damaged in terms of dysmorphic cells. Glomerular-type proteinuria was found in 11.4% of the participants 6 hours after the race. CONCLUSIONS: We conclude that long lasting, mild exertion is harmless for renal function, electrolyte balance and skeletal muscle as well as myocardial metabolism in healthy persons.

Does a 100-km walking affect indicators of vitamin status?

The status of thiamin (B1), riboflavin (B2), ascorbic acid (AA), and tocopherol was determined in 60 leisure athletes (age 46 +/- 10 y, BMI 23.7 +/- 2.0 kg.m-2, VO2max 39.4 +/- 6.5 ml.min-1.kg-1), who completed a 100-km walking race. Vitamin plasma levels and activities of erythrocyte transketolase (ETK) and glutathione reductase (EGR) were measured before start, immediately after finishing and 6 hours later. The participators finished the entire distance in 14.25 h (average speed 7 km.h-1). Before start, all participators showed an excellent vitamin status (prevalences of low vitamin status ranged between 1.7 and 1.8%). Plasma tocopherol concentrations correlated significantly with increased age (r = 0.35, p = 0.008). Compared to the values before start, plasma concentrations of B1 and B2 as well as ETK and/or EGR were increased significantly after finishing. The raised levels persisted 6 hours after finishing, whereas AA remained unaltered. The univariate analysis of variance revealed that the change in vitamin status after finish and 6 hours later was in part highly dependent on age, BMI and the level of physical fitness. Despite the long distance, the extensive character of the 100-km walking with its low intensity did not deteriorate the measured indicators of vitamin status.

[Importance of sports in the prime of life for prevention and rehabilitation]. / Bedeutung des Sports im Leistungsalter für Prävention und Rehabilitation.

Sports, physical fitness and motion are important factors for the improvement of health and physical power and performance at any age. Stress focussing on staying power is the most successful way to improve health for the prevention of diseases. In addition, physical fitness and sports can be used as "medication" for sick persons. The results of sports therapy show and prove the positive effect of physical fitness.

Determination of kinetic constants for the interaction between the platelet glycoprotein IIb-IIIa and fibrinogen by means of surface plasmon resonance.

The binding reaction between purified human platelet glycoprotein IIb-IIIa and fibrinogen was investigated by real-time measurements using the surface-plasmon-resonance sensor technology. In these experiments, either glycoprotein IIb-IIIa or fibrinogen was immobilized on a sensor surface. The time-dependent change in surface coverage that occurred immediately upon contact with a solution of the complementary protein was then detected. The ability to record this dynamic event from its initiation allowed the collection of kinetic and thermodynamic data over an extended time period. These data indicated that initially, in fast reaction, a reversible low-affinity complex with an equilibrium dissociation constant, Kd, of 155-180 nM was formed. In a subsequent slower reaction this complex was transformed into a more stable high-affinity complex with a Kd of 20-70 nM. Efficient dissociation of the high-affinity complex could only be induced in the presence of a competitive inhibitor such as RGDV. These data demonstrate that the binding between glycoprotein IIb-IIIa and fibrinogen is not a single monophasic reaction, but is composed of at least two consecutive processes both with their own kinetics.

Influence of aging, training and acute physical exercise on plasma glutathione and lipid peroxides in man.

In trained (long-distance runners) and untrained volunteers aged 22 to 57 years, basal plasma glutathione (GSH) concentration decreased significantly with increasing age. In most age groups basal GSH concentration of oxidized glutathione (GSSG) and lipid peroxides (LPO) was not influenced either by age or by training. Following acute physical exercise (bicycle ergometric test), which was maximal for each person and thus different in trained and untrained persons, plasma GSH, GSSG, and LPO concentrations were not changed at all in untrained volunteers. In trained persons, however, GSH concentration was significantly decreased by about 30%. Surprisingly, we observed a decrease in plasma LPO content by about 40%. GSSG content was not altered. The comparison with some physical-physiological parameters indicates that the changes in GSH and LPO concentrations depend on the extent of acute physical exercise rather than on previous training. Alterations of GSH and LPO in plasma could be of physiologic significance.

[A method for the fragmentation of bull spermatozoa and the isolation of median piece-tail fragments]. / Eine Methode zur Fragmentierung von Bullenspermien und Isolierung von Mittelstück-Schwanz-Fragmenten

A method is proposed for ultrasonic fragmentation of spermatozoa of Bos taurus followed by the isolation of a middle piece-tail-fraction.