Metal and metallothionein content in tissues from wild and farmed Anguilla anguilla at commercial size.

Metallothionein and metal content (Cd, Zn, Hg, Cu, Fe, Pb and Mn) were determined in various organs of commercially available eel (Anguilla anguilla) of similar size obtained from a local farm and from The Albufera Lake in Valencia (Spain). Farmed fish showed statistically significant higher Cd concentrations in liver and kidney whereas wild individuals had higher levels of Pb in blood and Zn in kidney. Significant positive correlations were found between metallothionein and Cd in kidney of farmed eel and between metallothionein and Cu in liver of wild ones. No statistically significant differences were found between the two populations in the concentration of any of the metals analyzed in muscle and in all instances these levels were lower than the limits established by the Spanish legislation for fish destined for human consumption.

Blood ammonia response during incremental and steady-state exercise in military staff.

BACKGROUND: Although in the last few years it has been possible to determine blood ammonia, its application in coaching practice has not yet been fully established. This study was designed to evaluate the blood ammonia response to a laboratory incremental exercise test and three steady-state field tests. METHODS: There were 26 military personnel who performed a submaximal and maximal exercise test on a treadmill, and a field test which included three different constant velocity stages. Gas exchange parameters were monitored throughout the maximal test. Capillary blood samples were obtained from fingertips during the submaximal and field tests for the determination of ammonia and lactate. RESULTS: The ammonia threshold was detected in 23 subjects (88.5%) during the submaximal test. No significant differences were found between the ammonia and lactate thresholds which were shown to be significantly correlated. Blood ammonia levels showed a progressive increase during the last two stages of the field test while lactate levels remained stable at less than 4 mmol x L(-1). CONCLUSIONS: The steady increase in blood ammonia concentration recorded in the field test suggests the possibility of using blood ammonia levels to monitor the duration of exercise although further investigation is required to explore this possibility. Moreover, the assessment of blood ammonia levels during incremental exercise protocols confirms the existence of an ammonia threshold, defined as the intensity of exercise at which ammonia shows a progressive increase.

Trace elements and electrolytes in human resting mixed saliva after exercise.

OBJECTIVES: Exercise is known to cause changes in the concentration of salivary components such as amylase, Na, and Cl. The aim of this investigation was to evaluate the effect of physical exercise on the levels of trace elements and electrolytes in whole (mixed) saliva. METHODS: Forty subjects performed a maximal exercise test on a cycle ergometer. Samples of saliva were obtained before and immediately after the exercise test. Sample concentrations of Fe, Mg, Sc, Cr, Mn, Co, Cu, Zn, Se, Sr, Ag, Sb, Cs, and Hg were determined by inductively coupled plasma mass spectrometry and concentrations of Ca and Na by atomic absorption spectrometry. RESULTS: After exercise, Mg and Na levels showed a significant increase (p < 0.05) while Mn levels fell (p < 0.05). Zn/Cu molar ratios were unaffected by exercise. CONCLUSIONS: Intense physical exercise induced changes in the concentrations of only three (Na, Mg, and Mn) of the 16 elements analysed in the saliva samples. Further research is needed to assess the clinical implications of these findings.

Saliva composition and exercise.

Little attention has been directed toward identifying the changes which occur in salivary composition in response to exercise. To address this, our article first refers to the main aspects of salivary gland physiology. A knowledge of the neural control of salivary secretion is especially important for the understanding of the effects of exertion on salivary secretion. Both salivary output and composition depend on the activity of the autonomic nervous system and any modification of this activity can be observed indirectly by alternations in the salivary excretion. The effects of physical activity (with reference to factors such as exercise intensity and duration, or type of exercise protocol) on salivary composition are then considered. Exercise might indeed induce changes in several salivary components such as immunoglobulins, hormones, lactate, proteins and electrolytes. Saliva composition might therefore be used as an alternative noninvasive indicator of the response of the different body tissues and systems to physical exertion. In this respect, the response of salivary amylase and salivary electrolytes to incremental levels of exercise is of particular interest. Beyond a certain intensity of exercise, and coinciding with the accumulation of blood lactate (anaerobic threshold or AT), a 'saliva threshold' (Tsa) does indeed exist. Tsa is the point during exercise at which the levels of salivary alpha-amylase and electrolytes (especially Na+) also begin to rise above baseline levels. The occurrence of the 2 thresholds (AT and Tsa) might, in turn, be attributable to the same underlying mechanism, that of increased adrenal sympathetic activity at high exercise intensities.