One of the best-studied responses of cognitive evoked potentials is a so-called “P300”, the late positive wave complex that occurs about 300-500 ms after the stimulus. It is obtained when the subject’s attention is focused on a signal that is rare, especially if the signal has a motivational or emotional meaning. In the study of P300 potential, we followed the variations of potential amplitude and latency, so the objective was to examine whether there is a difference in Fz and Cz amplitudes of auditory induced cognitive evoked P300 potential depending on the performance of oddball tasks, both in male and female subjects. The study included 60 subjects (30 female respondents and 30 male respondents). P300 potential is induced by the auditory "oddball" paradigm with 80% of non-target and 20% of target stimuli that are presented to the patient through headphones. The target tones are high tones of 2000 Hz. The standard, 1000 Hz tones the respondent should ignore but when he hears the target tones the respondent should press the button on the special handle. The value of Fz and Cz amplitudes both in male and female subjects obtained in the classical "oddball" paradigm when the subject reacted to the signal by pressing the key with the dominant (right) arm were statistically significantly lower (p>0,05) than the values of Fz and Cz amplitudes obtained when the key was pressed by the non-dominant hand. Based on this experiment it can be concluded that both in male and female subjects the performance of oddball tasks does not affect the amplitude of P300 cognitive evoked potentials.

The first suggestion that physical exercise results in free radical-mediated damage appeared in 1978, and since that time the sources of oxidant production during exercise continue to be debated. Many researchers focused on the damaging effects of oxidants in muscle (oxidative damage of proteins and lipids), but the examination of cell-signaling effects of free radicals on muscle activity became today's main issue. Free radicals can modulate a number of cell signaling pathways and regulate the expression of multiple genes, contributing to the muscle adaptation on exercise and improving the muscle force production. Those effects are provided by changes in calcium handling by muscle cells or changing in the sensitivity of myofilaments to calcium. As a conclusion we can say that low and physiological levels of free radicals are required for normal force production in skeletal muscle and antioxidant adaptation, while high levels of free radicals promote contractile dysfunction resulting in muscle weakness and fatigue.

Strenuous exercises greatly increase oxygen consumption in the whole body, especially in skeletal muscles. Large part of oxygen consumption is reduced to H2O and ATP, but smaller part (2-5%) results in an increased leakage of electrons from the mitochondrial respiratory chain, forming various reactive oxygen species-ROS (02, H2O,iOH). These free ra- dicals are capable of triggering a chain of damaging biochemical and physiological reactions (oxidative stress, lipid peroxi- dation), as a base for skeletal muscles damage after exercise. MDA (malondialdehyde) is a marker of exercise induced lipid peroxidation process. L-ascorbic acid is a major aqueous-phase antioxidant. To estimate antioxidant role of ascorbic acid we use rate between dehydroascorbate and ascorbate. In this paper those markers of lipid peroxidation (MDA, MDA ind, % ind MDA), and ascorbic acid status (ascorbic acid Asc, ascorbat A, dehidroascorbat DHA, DHA/A) were determinated in 30 stu- dents, in rest and after treadmill running protocol (Bruce Treadmill Protocol). It was found that after the treadmill test, plas- ma MDA level had increased from 3,04 to 4,39 M/L (p<0,0001) and % ind MDA decreased significantly from 35% to 24,7% (p=0,0003). Plasma ascorbic acid was also found to be higher after the treadmill test comparing to rest level (from 55,4 to 67,6 μM/L). DHA/A level in rest was 1,62 and after treadmill test it increased to 2,05 (p=0,0014). These results suggests that strenuous exercise increased process of lipid peroxidation (MDA †, % ind MDA), but in the same time incre- ased ascorbic acid level in plasma and DHA/A rate indicates stronger activation of nonenzymatic antioxidant defense system.

It is well known that intensive physical activity increase the production of reactive species of O and N (RONS), but 2 it is also known that moderate and regular physical activity has influence on antioxidative system adaptation and help in repairing process of oxidative damage. In this paper we estimated markers of lipid peroxidation (MDA, % ind MDA), and antioxidant status (Asc, DHA/A, GSH, CAT, Pex) for 30 students (control group), and 30 professional football players (regular intensive physical activity). In the group of professional sportsman there were significant increase of lipid peroxidation markers (MDA ↑, % ind MDA ↑), which was also followed by an increased antioxidant activity (Asc ↑, DHA/A ↑, GSH ↑, Pex ↑, CAT ≈). We can conclude that chronic physical activity significantly improves antioxidant status using the adaptation process.

Biological equality assessments are carried out by means of: a) comparative pharmacokinetic study; b) comparative pharmacodynamic study; c) controlled comparative clinical experimentation; d) comparative in vitro assay (dissolution test). The first method mentioned, i.e. determining the concentration of a drug in the blood of healthy volunteers, is the most accurate and most frequently employed. In this paper, a study conducted on healthy volunteers that displays the possibility of evaluating biological equality using pharmacodynamic variable data, giving the example of such assay of retard tablets of verapamil produced by two different companies, is presented. Taking into account the effects of this drug, biological equivalence was proved by comparing pharmacodynamic variables such as PR interval, systolic and diastolic blood pressure and heart rate.

Conducting research in the field of respiratory function, by using measuring and testing, has many purposes. First of all, it could show us how lungs function as a whole, but also, it could lead us to the exact location of a disorder. The aim of this paper is to, by employing accurate correlation of the measured variables of the flow/volume and flow/pressure curves, determine the location of the obstruction process in the tracheobronchial tree, in central-upper airways, as well as in a segment of small airways, so called 'silent zones' of the lungs, smaller than 2 mm in internal diameter. This research included 115 healthy people and 106 patients with chronic obstructive lungs disease, of both genders. The following values of the measured lungs' function parameters were found among healthy people (% of predicted value): FVC- 93%; FEV - 91,1 %; 1 FEV x 100/ FVC- 98,7%; MEF - 107,9%; MEF - 87,5%; MEF-98,9%; Rt-147,1%; ITGV-103,3%; SRt- 130,7%. 1 25%FVC 50%FVC Among the patients with chronic obstructive bronchitis, the following results of the examined parameters were gained: FVC- 66,3%; FEV - 54,2%; FEV x 100/ FVC- 80,7%; MEF - 19,3%; MEF - 23,1%; MEF- 40,5%; Rt- 51,2%; 1 1 25%FVC 50%FVC ITGV- 162,1%; SRt- 36,2%. Finally, there was a certain number of the healthy examinees who showed that direct indicators of the air flow resistance (Rt, SRt) were not significantly changed, while indirect indicators of the respiratory tracts obstruction (MEF , MEF ) were reduced, comparing to the expected tabular results.

Many researchers and clinical doctors have realized that spirometric tests, as well as the resistance of airways, could be within the normal limits at people who have clear signs of bronchitis (coughing, expectoration and lighter disphnoe). Very often, especially among smokers, they have found discrepancy between the functional tests' results and clinical symptoms, although they could expect to find minor lungs' diseases within this group of people. Obstructive lesions in small airways are very often present at smokers older than 40 years, whose lungs are macroscopically normal, and who do not show clinical signs of the obstructive lung disease ('asymptomatic smokers'). The aim of the paper was to find which test, among the most often-used tests for the functional research of the respiratory system, represented the best indicator of the initial obstructive changes localized in small airways. The research study included 50 asymptomatic smokers (34 male and 16 female) ranging from 44 to 57 years. The results of the achieved FVC were at normal level, at all examinees. Out of 50 examinees, asymptomatic smokers, there was one examinee (2%) with the lower level of FEV , while at two examinees 1 (4%) lower levels of SRt and MEF were found. Significantly lower levels of the measured MEF were found among 50%FVC 25%FVC 16 asymptomatic smokers (32%). Such a functional result, i.e. a decrease of MEF while the levels of FVC, FEV , Rt, 25%FVC 1 SRt and MEF are normal, accompanied by a long-lasting smoking case-history with less expressed symptoms, points at 50%FVC the existence of the obstructive disorders localized in the periphery parts of the bronchial tree (small airways). The registration of the flow/volume curve and its analysis might be used as a test even more sensitive than spirometry and body pletizmografy; as a test it can be used for a diagnosis of initial obstructive difficulties in small airways, in other words, it could diagnose the small airways disease.