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Biomedical subjects

V Filcescu

Publications and source records attributed to V Filcescu.

At least 19 recordsLinked to original sources
PubMed1982

The influence of day and night work on the circadian variations of cardiovascular performance.

Circadian variations of the pre-ejection period, Q-T interval, heart rate and oral temperature at rest and in day and night shift work were investigated. At rest, pronounced circadian variation was found in heart rate, pre-ejection period and Q-T interval. The ratio between Q-T interval and heart rate also shows a distinct circadian variation. When working, the rest rhythms of the variables were obscured. The physiological implications for shift work are discussed.

Adolescent↗
PubMed1978

A method for continuous electrocardiodynamic monitoring.

A new method is presented for the monitoring of cardiac time intervals, e.g. in clinical and industrial work investigation. The methods yields 'on-line' the electrocardiodynamic time profile during rest as well as effort, and has applications in health care, sports and occupational medicine. By means of analog processing of an electrocardiographic signal, ear densitogram and beat-by-beat display of the measured cardiac time intervals as amplitude-modulated pulses, an 'electrocardiodynamic time profile' is obtained. In order to estimate the accuracy and the limitations of the method, a comparison with computerized methods was performed. In an ergonomic experiment carried out by a Romanian-Swedish research team, analog and digital methods for the detection of cardiac time intervals showed good agreement.

Adolescent↗
PubMedDate not supplied

Mental stress enhances the sympathetic fraction of QT variability in an RR-independent way.

In 10 healthy male volunteers aged 19-20, spectral power of the beat-by-beat QT interval was measured at the Traube-Herring-Mayer (THM) band (0.05 to 0.15 Hz) when the subject was at rest and during atrial pacing. After resting in dorsal decubitus for 10 minutes, right atrial pacing was performed at a slight elevation above sinus rhythm as well as at 100 or at 110 beats per minute for 7 minutes each. In addition, during pacing at 100 or 110 bpm, the subject was required to perform a Kraepelin Arithmetic test. There was a statistically significant increase in QT spectral power at the THM band, while heart rate was maintained unchanged during the periods of mental stress versus rest. This experiment confirms the potential independence of the QT interval from heart rate and suggests that THM fraction of QT spectral power has a double subordination: during relaxed rest it follows mostly RR-fluctuation; during stress an RR-independent contribution is added, which presumably reflects the supra-normal sympathetic drive on the ventricles.

Adult↗
PubMedDate not supplied

Activity of Na+/K+-ATPase and of Ca++-ATPase under the action of adenosine triphosphate in experimental myocardial hypertrophy.

This paper presents the results of our research on the mechanisms involved in the modifications occurring in the activity of ionic pumps (Na+/K+-ATPase and Ca++-ATPase) at the level of the sarcolemma, the sarcoplasmic reticulum and mitochondrial membrane of the myocardial cell in experimental myocardial hypertrophy induced by isoproterenol. We also studied the effects of concomitant administration of adenosine triphosphate. Thus, we found the activity of the sarcolemmal Ca++-ATPase intensely increased under the action of isoproterenol, while Ca++-ATPase activity in the sarcoplasmic reticulum decreased significantly. At the same time, the Na+/K+-ATPase activity decreased both in the sarcolemma and in the sarcoplasmic reticulum. Administration of adenosine triphosphate induces opposite effects, of lower intensity, upon the activity of the two ATPase, that tend to offset the the effects of isoproterenol. This was found in the group of rats given concomitantly both isoproterenol and adenosine triphosphate. A better understanding of the processes involved in those modifications of membrane ATPase activity allows us to consider their different behaviour to isoproterenol and adenosine triphosphate as the expression of intrinsic mechanisms by means of which the myocardial cell intervenes in maintaining a physiological concentration of calcium ions (Ca++) that is necessary both in order to avoid a failure of the contractile apparatus and in order to preserve the mitochondria role of ATP supplier. Our results demonstrate the antiadrenergic action of adenosine triphosphate that attenuates isoproterenol effects on cardiac myocytes.

Adenosine Triphosphate↗