Studies of aluminum in rat brain

The effects of high aluminum concentrations in rat brain were studied using(14)C autoradiography to measure the uptake of [(14)C]2deoxy-D-glucose ([(14)C]2DG) and microbeam proteon-induced X-ray emission (microPIXE) with a 20-μm resolution to measure concentrations of magnesium, aluminum, potassium, and calcium. The aluminum was introduced intracisternally in the form of aluminum tartrate (Al-T), and control animals were given sodium tartrate (Na-T). The(14)C was administered intravenously. The animals receiving Al-T developed seizure disorders and had pathological changes, which included cerebral cortical atrophy. The results showed that there was a decreased uptake of [(14)C]2DG in cortical regions in which increased aluminum levels were measured, i.e., there was a correlation between the aluminum in the rat brain and decreased brain glucose metabolism. A minimum detection limit of about 16 ppm (mass fraction) or 3×10(9) Al atoms was obtained for Al under the conditions employed.

[Dynamics of left ventricular systole in primary arterial hypertension with a positive submaximal stress test]

There was made an exercise test until appearing exercise limiting symptoms in 50 patients with the second period of primary arterial hypertension (PAH) and in 73 healthy subjects. Exercise test was positive in 26 PHA patients (group I), and was negative in 24 (group II). Negative exercise tests were stated also in a group of 73 healthy subjects (control group-III). Tolerance of physical exercise, probability of coronary heart disease, rest and exercise arterial blood pressure values and left-ventricular systolic time intervals (LVSTI) were analysed in these groups. The preejection period (PEP) and PEP/LVET ratio increased and left-ventricular ejection time index (LVETI) decreased at rest in patients with the second period of PAH as compared in healthy subjects. It proved that left-ventricular mechanical function had been damaged. Submaximal physical exercise proceeded however with similar changes of LVSTI as healthy subjects. There were found high pretest probability of coronary heart disease, decreased tolerance of submaximal physical effort and decreased left-ventricular mechanical function in patients with positive exercise test. Rest values of PEPI and PEP/LVET ratio were significantly higher and LVETI were lower in I than in II (p less than 0.05) an in III group (p less than 0.001). Increased values of PEPI, LVETI and PEP/LVET ratio in relation to the second group and much more as compared in the control group were observed during physical effort.

Adaptation of the circulatory system to frequently repeated submaximal workloads in the light of left ventricular contraction analysis

In two groups of healthy men aged 20-22 years the left ventricular systolic time intervals were evaluated by the method of Weissler et al. during frequently repeated workloads and restitution. Each exercise was carried out on a Zimmerman cycle ergometer during 10 minutes, and was repeated five times at 50-minutes intervals from 8.00 o'clock a.m. Group I (15 subjects) performed the exercise at a stable workload which produced during the first exercise heart rate acceleration to 170/min, but gave a successive further rise in the heart rate during consecutive exercises. Group II (11 subjects) performed all exercises to a stable rise in heart rate to 170/min with decreasing workloads. It was found that successive exercises caused in both groups a similar decrease of the left ventricular ejection time index (LVETI), pre-ejection period (PEP), isovolumetric contraction time (ICT), and decrease of the PEP/LVET index (p less than 0.05). Each successive exercise began with higher values of LVETI, PEP, ICT and PEP/LVET than the first one. No significant differences were found in the values of left ventricular systolic time intervals in both groups (p greater than 0.05). The duration of restitution of normal values of the left ventricular systolic time intervals after successive exercises was not changing but the tolerance of these exercises measured by heart rate increase and work performed decreased successively.

Effect of blood loss on the plasma level of whole peptides and their fractions at rest and during exertion and restitution

The plasma level of peptides and their fractions was investigated in 12 male voluntary blood donors aged 19-23 years at rest, during exercise and restitution before and 1 and 24 h after blood withdrawal. In each test the subjects exercised on Monark's cycle ergometer under loads producing a heart rate acceleration up to 170/min (Physical Working Capacity -- PWC 170). Blood loss produced a non-significant decrease in the plasma peptide level. During exercise the levels increased significantly both before (P less than 0.001) as well as 1 h and 24 h after blood loss (P less than 0.025). About one half of the increase was due to haemoconcentration. During restitution the levels were not significantly different from the initial values. Blood loss gave rise to a significant increase in the level of fractions of a molecular weight exceeding 3500 while the concentration of fractions of 1500-3500 molecular weight decreased. The changes in the peptide fractions were slightly different in the case of exercise performed after blood loss from those observed before blood loss. This applies first of all to fractions with a molecular weight below 750 whose concentration decreased during exercise performed after, and increased before, blood loss.

Effect of the time of the day on left ventricular systole and diastole dynamics

Synchronous recording of ECG from the second lead, phonocardiograph from the Erb's point and right carotid sphygmogram was performed in 20 healthy men aged 20 to 25 years four times during a 24-hour period: at 9:00 a.m., at 4:00 p.m., at 2:00 a.m. after awakening, and at 2:00 a.m. during all-night activity. The obtained polycardiograms were analysed by the method of Weissler calculating the measured and corrected left ventricular contraction periods. An increase was observed in the dependence of the diastole time (D), total electromechanical contraction time (QS2) and the left ventricular ejection time (LVET) on the heart rate (HR) in the night hours. Moreover, the functional reserve of the heart increased during the night as demonstrated by prolongation of the D time and decrease of QS2 in the heart cycle (R-R). It was found also that during the night hours the LVET and QS2 values and the pre-ejection period (PEP) were significantly greater independently of the degree of activity than in the morning and afternoon (p less than 0.05).

Furosemide effect on gastric basal secretion during exercise and postexercise restitution in healthy subjects

The purpose of this work was determination of furosemide effect on basal gastric secretion during exercise and postexercise restitution in 8 healthy men aged 22-25 years. The investigations were performed three times determining each time the basal acid output during three successive hours. In the first test the determinations were done during one hour rest, then after intravenous furosemide administration 2 mg/kg, and again between 60 and 120 minutes after the injection. In the second test BAO was determined at rest, during one-hour exercise, and during restitution. In the third test the determinations were done at rest, during exercise preceded by furosemide injection as in the first test, and during one hour of post-exercise restitution. The exercise on a Monark cycle ergometer was, on the average, 275 210 +/- 12 500 J in the second test and 284 870 +/- 14 480 J in the third test. Furosemide caused a statistically significant decrease of BAO at rest (p less than 0.02) and during exercise (p less than 0.01), this was due to a significant reduction in gastric juice volume (p less than 0.001) and in the second hour of furosemide action also to a decrease of HCI concentration (p less than 0.05). Decreased excretion of electrolytes by the gastric mucosa was proportional to changes in gastric juice volume. The 24-hour urinary excretion of sodium, potassium and chlorides increased after furosemide in the first test (p less than 0.001), and in the third test (p less than 0.02).

Effect of exogenous glucagon on left-ventricular contraction dynamics during restitution after exercise in healthy men

In two groups of healthy men the dynamics of left-ventricular contraction was studied by Weissler's method based on synchronous recording of ECG, phonocardiogram and carotid sphygmogram. Group I comprised 20 subjects in whom this recording was performed during maximal exercise and 90-minute restitution (1 W/kg/6 min, 2 W/kg/6 min, 3 W/kg/6 min). Group II (n = 17) performed the same exercise immediately after intravenous injection of glucagon 50 micrograms/kg of body weight. Glucagon administration before the exercise reduced the functional reserve of the left ventricle during the exercise impairing the pumping action of the left ventricle during the restitution. After glucagon administration the restitution of left-ventricular contraction periods was characterized by decreased value of the ejection time index (LVETI), prolonged pre-ejection period (PEP), isovolumetric contraction time (ICT), and diminished LVET/PEP index in relation to the values obtained at the same time in the control group (p less than 0.05). Glucagon caused no changes in the exercise tolerance of the studied subjects and had no effect on the time of postexercise restitution.

Changes in the concentrations of certain biochemical parameters in the peripheral blood during exercise and restitution after bloodletting

The reported investigations were carried out in 18 men aged 19 to 23 years in whom 400 ml of whole blood was removed. On the day before bloodletting, one hour and 24 hours after it the studied men carried out a 10 minute exercise on a Monark cycle ergometer at a workload raising the heart rate to 170/min. Before the exercise, immediately after it and in the 30th minute of restitution venous blood samples were taken for determinations of the concentrations of total protein, albumins, free fatty acids, glucose, lactate and pyruvate, and the activity of lactic dehydrogenase, alanine aminotransferase and aspartate aminotransferase. During that time the acid-base equilibrium was determined in capillary blood. After bloodletting the concentrations of albumins, total protein and free fatty acids were decreased parallelly to haematocrit value decrease (p less than 0.05) and glucose concentration increased slightly (p less than 0.05). Enzyme activity was decreased slightly (p greater than 0.05). The partial oxygen pressure decreased, that of carbon dioxide increased, and hydrogen ion concentration rose. These changes were more pronounced after 24 hours than 1 hour after bloodletting. After submaximal exercise and in the 30th minute of restitution as well as 1 and 24 hours after bloodletting the changes in the concentrations of the biochemical parameters, enzyme activity and acid-base equilibrium were similar as after bloodletting.

Effect of several cigarettes smoked uninterruptedly on left ventricular systolic time intervals in healthy subjects

The reported investigations were carried out in 50 healthy young men. Twenty of them (group I) performed a three-grade exercise on a Zimmermann cycle ergometer after smoking 4 "Sport" cigarettes, while another 30 subjects served as controls (group II). The exercise was carried out at 60 r.p.m. at a power of 1 W/kg body weight/6 minutes, 2 W/kg/minutes, and 3 W/kg/6 minutes. Between the successive phases of the exercise the subjects rested for 10 minutes. Group I performed work of 148 610 +/- 11 576, and group II--146 632 +/- 19 706 J (p greater than 0.01). The left ventricular systolic time intervals were calculated from synchronous records of the 2nd lead of the ECG, phonocardiogram obtained at Erb's point, and right carotid sphygmogram at rest, after cigarette smoking, immediately after successive phases of the exercise, and during 4 hours after exercise completion. Immediately after smoking 4 cigarettes a decrease was observed in the left-ventricular ejection time index (LVETI), a rise in the value of the pre-ejection period index (PEPI), and a decrease of the left-ventricular mechanical work index (LVET/PEP). These changes evidenced indirectly impairment of myocardial contractility. During the exercise after cigarette smoking no unfavourable changes were observed in left-ventricular pump-like activity in relation to the control group. The restitution period in group I was associated with an increase in PEPI value and reduction of LVETI value which were significantly greater than in controls (p less than 0.01). Despite disturbances in myocardial contractility cardiovascular system restitution was as long as in the control group.

Effect of 400 ml blood loss on adaptation of certain functions of the organism to exercise

Eighteen men aged 19-23 years, volunteer blood donors, donated 400 ml of blood. Twenty-four hours before donation, one hour and 24 hours after it they performed a 10-minute exercise on Monark cycle ergometer at workloads raising the heart rate to 170/min. During the exercise the oxygen uptake (VO2), carbon dioxide elimination (VCO2), respiratory quotient (RQ), oxygen uptake to maximal oxygen uptake ratio (VO2/VO2 max), heart rate (HR) and systolic and diastolic arterial blood pressure (Ps and Pd) were determined. The obtained results were compared with the values of haemoglobin concentration and erythrocyte count. One hour after blood donation raised values of HR and Pd were obtained (p less than 0.05) with decreased Ps (p less than 0.05) and VO2 (p less than 0.05). Twenty-four hours after blood loss these parameters were not different from the initial ones (p less than 0.05). Submaximal exercise performed 1 hour after blood loss produced a significantly greater increase of the heart rate than this exercise performed before blood loss. The values of VO2, VCO2, and VO2/VO2 max were slightly lower and those of RQ and HRXPs slightly higher than during control exercise (p less than 0.05). Exercise performed 24 hours after blood loss caused identical changes in these parameters as during control tests.

Plasma biochemical changes and acid-base equilibrium changes in capillary blood nursing frequency repeated submaximal physical exercise in untrained subjects

The reported investigations were carried out on healthy men aged 20--22 years in two groups: group A of 11 subjects and group B of 12 subjects. Both groups performed five times at 50-minute intervals submaximal physical exercise during 10 minutes on a Monark ergometer. Group A performed the exercise at a steady heart rate of about 170/min with variable workload, while group B performed it at a steady workload but changing heart rate. At rest and after each exercise the plasma concentrations of free fatty acids, glucose and amino-acid nitrogen were determined in both groups, and changes in the parameters of acid-base equilibrium were studied in capillary blood. It was found that after each consecutive exercise the concentration of free fatty acids (FFA) increased ever more and the rise of the haematocrit index decreased. Glucose concentration decreased after the 1st, 2nd and 3rd exercises, but increased after the remaining two exercises. The concentration of amino-acid nitrogen showed an increasing tendency after exercise in both groups. The changes in the acid-base equilibrium, that is its shifting towards metabolic acidosis were greatest after the first exercise. In group A each consecutive exercise caused less pronounced disturbances of acid-base equilibrium. In group B the intensity of metabolic acidosis was lower in consecutive exercises in relation to the first one, but it was greater than in group A.

Effect of training on left ventricular contraction dynamics at rest and during maximal exercise

Left ventricular contraction parameters were determined in sitting position in 21 road cyclists before and after a six-month training course at rest and after maximal exercise. For assessing the contractility of the heart synchronous records were obtained of the second ECG lead, phonocardiogram at Erb's point and right carotid sphygmogram. The polycardiograms were analysed by the method of Weissler. After completion of training the correlation between the total electromechanical systole (QS2) and the left-ventricular ejection time (LVET), on the one hand, and the heart rate, on the other hand, was less pronounced. Moreover, the total electromechanical systole index (QS2I) and the left-ventricular ejection time index (LVETI) were significantly (p less than 0.001) smaller, and the pre-ejection period (PEP) and the PEP/LVET ratio were significantly (p less than 0.05) greater than before the training course. During maximal exercise in both investigations the values of QS2I, LVETI, PEP, PEP/LVET ratio and isometric contraction time (ICT) were reduced (p less than 0.001). After the training PEP and PEP/LVET decreased more (p less than 0.05) than before training. The obtained results point to a greater functional reserve of the heart at rest, greater myocardial contractility during exercise, and lower decrease of stroke volume during exercise to exhaustion after 6 months of training than before training in relation to the values of these parameters before training in the same subjects.

Changes in concentrations of basic energy-yielding substrates in plasma during maximal effort and postexercise restitution in relation to training level

Fifty-three cyclists aged from 19 to 32 years were divided into three groups depending on the degree of physical fitness. Group I comprised 13 cyclists with high fitness, group II 19 cyclists with medium physical fitness, and group III 22 cyclists with low physical fitness. All studied subjects carried out work on a Monark cycle ergometer until they refused to go on (exhaustion). During the exercise the consumption of oxygen was determined and the heart rate was measured. Other determinations included the levels of free fatty acids, glucose, amino-acid nitrogen, total protein, lactate in the venous blood and haematocrit index at rest, after the exercise and in the 15th and 30th minutes of postexercise restitution. The differences between the groups were analysed. It was found that in group I the blood glucose level rose more than in the other groups, and the levels of FFA and amino-acid nitrogen increased while in groups II and III they decreased during the exercise. The direction of changes of the various parameters during the restitution was similar in all groups but their intensity was different in individual groups. Lactate concentration showed no differences between the studied groups during the exercise as well as during the restitution.