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Biomedical subjects

Z Marton

Publications and source records attributed to Z Marton.

5 recordsLinked to original sources
PubMed2001

Scavenger effect of experimental and clinically used cardiovascular drugs.

Oxygen free radicals play an important role in several physiologic and pathophysiologic processes. In pathophysiologic circumstances they can modify and damage biologic systems. Their functional properties (exposed to high oxygen tension) place red blood cells among the most susceptible cells to the harmful effect of free radicals. Because oxygen free radicals are involved in a wide range of diseases, scavenging these radicals should be an important therapeutic approach. In this study the antioxidant capacities of experimental and clinically used cardiovascular drugs were investigated. Phenazine methosulfate was used to generate free radicals and thus harden red blood cells. Filtration technique and potassium leaking were used to detect the scavenging effect of the examined drugs. The experimental drug H-2545 provided 43% protection against phenazine methosulfate-induced changes in red blood cell filterability (p < 0.001). Although some of the examined, clinically used cardiovascular drugs (carvedilol, metoprolol, verapamil, trimetazidine) also showed significant (p < 0.05) antioxidant effect, they were less efficient than H-2545. The scavenger effect of this novel drug exceeded the antioxidant properties of vitamin E. Modification of mexiletine with a pyrroline ring significantly improved its antioxidant capacity, suggesting that this molecular segment is responsible for the antioxidant effect.

Anti-Arrhythmia Agents↗
PubMed2001

QRS Score: a composite index of exercise-induced changes in the Q, R, and S waves during exercise stress testing in patients with ischemic heart disease.

BACKGROUND: To detect ischemic heart disease, the exercise-induced ST-segment displacement is the most frequently used ECG parameter. However, the value of this marker was proven to be limited with varying sensitivity and specificity. A new parameter, called QRS score, emerged to improve the efficacy of exercise testing. METHODS: Our study aimed at evaluating the diagnostic value of QRS score in ischemic heart disease, investigating males and females separately, and examining the effects of heart rate and antiischemic medication. QRS score and cumulative ST depression were calculated in 212 patients and correlated to the findings of the stress myocardial perfusion SPECT (197 subjects) or coronary angiography (54 subjects). RESULTS: An inverse correlation could be found between the QRS score and the results of myocardial SPECT and coronary angiography in the whole population, especially in males; females did not show a significant relationship. In patients with conclusive tests (achieving 85% of the maximal predicted heart rate) QRS score correlated significantly with the results of the stress myocardial perfusion SPECT and coronary angiography. The sensitivity, specificity, and validity of the QRS score surpassed those of the cumulative ST depression in the entire population as well as in patients with conclusive tests. The antiischemic medication did not affect correlation values. CONCLUSION: QRS score was significantly related to the extent of myocardial ischemia and the severity of coronary heart disease, thus along with the analysis of ST-segment displacement may contribute to the more precise evaluation of exercise testing.

Coronary Angiography↗
PubMed2001

Red blood cell aggregation measurements in whole blood and in fibrinogen solutions by different methods.

Red blood cell (RBC) aggregation is an important component of whole blood viscosity, especially at low shear rates, and is the major cause of the non-Newtonian flow properties of normal blood. In different laboratories several methods are used to determine RBC aggregation, therefore the standardization of aggregation measurements is especially important for getting comparable results. Aggregation indices of 62 human blood samples were determined by two different methods; LORCA (Laser-assisted Optical Rotational Cell Analyzer) and Myrenne aggregometers and related to plasma fibrinogen concentration. Our results show closer correlation values between RBC aggregation and fibrinogen concentration, when RBC aggregation was measured by LORCA (p<0.001), although correlation could be revealed with Myrenne, when plasma fibrinogen level was less than 4.5 g/l. Correlation coefficient between aggregation indices measured by LORCA and Myrenne aggregometers was also closer below this fibrinogen level. In vitro examination of RBC aggregation in fibrinogen solutions showed that higher fibrinogen concentration results in higher RBC aggregation only up to a certain level similarly to that found in human whole blood samples. Our results show that plasma fibrinogen level has an important, concentration dependent effect on RBC aggregation in human blood, but above a certain level it may not cause further aggregate formation.

Adult↗