CARDIOVASCULAR POTENTIAL OF THE BARKS OF TRUNK OF BUCHHOLZIA CORIACEA (CAPPARIDACEAE) AT THE ALBINO MALE RAT

Buchholzia coriacea is a plant of the Congolese pharmacopeia. Her barks of trunk were the subject of aphrodisiac study in our laboratory. But her effect on the arterial pressure, the cardiac frequency and on the contractions of the heart, remain even unknown. This is how the present work aims the assessment of the cardiovascular potential of the barks of trunk of this plant at the albino male rat. The effects on the mean arterial pressure and the cardiac frequency at the rat normotended have been valued by the method invasive whereas the classic model of drip of isolated heart of batrachian has been used to value the effects on the heart isolated of toad. The administration of the aqueous extract of the barks of trunk of B. coriacea (10, 20 and 40 mg/kg, i.v) decreases the mean arterial pressure and the cardiac frequency as the yohimbine(1mg/kg, i.v) and the µg acetylcholine (50 µg / Kg, i.v).This effects hypotensor and negative chronotrope are raised completely by the atropine (1 mg / kg. i.v), ce that conrms the implication of the receiving muscarinics in the mechanism of action of this extract. To the concentrations of 2; 2,5 and 3 mg / ml extracts it aqueous of the barks of trunk of B. coriacea decreases strength and the frequency of the contractions of the heart isolated of toad and to 4 and 5 mg/ml, it drags to a reversible stop of the contractions of the heart isolated of toad.

Protease inhibitor-contaning antiretroviral therapy effects on QT interval and heart rate: a cross-sectional study

Background HIV has been associated with QT prolongation and it is believed this is from drug interaction as well as HIV infection. In vitro studies have showed that protease inhibitors block potassium channel HERG, suggesting that these drugs can cause drug-induced QT prolongation. Few case-reports have showed that protease inhibitors can cause drug-induced bradycardia, but data is still limited. Objective To describe the correlation between HIV infection and the duration of QT interval and to evaluate the effects that protease inhibitors-containing antiretroviral regime have on the duration of QT interval and cardiac frequency. Methods A cross-sectional study was made. Participants were assigned to 3 groups: HIV positive with antiretroviral therapy which included protease inhibitors (HIV+ with treatment), treatment-naïve HIV positive and HIV negative. None of the participants had past medical history of cardiovascular disease or use of known QT prolonging medication. 12-lead ECG were made to all participants. QT interval and cardiac frequency were measured to be compared between the 3 groups and the results were analyzed by the statistical test ANOVA. Results A total of 213 participants were enrolled, 84 in the HIV+ with treatment, 45 in the HIV+ treatment-naïve, and 84 HIV-. 63% of the participants were males. The treatment-naïve HIV+ group only had 5 female participants. This study did not find a relation between HIV infection or protease inhibitor use and an increase in the duration of QT interval in males. For females, this study found an association between HIV infection and longer QT interval duration, as seen in the mean of each group: 442.8 ms for treatment-naïve HIV+ group, 422.42 ms for protease inhibitor HIV+ with treatment group and 420.34 ms HIV- group. It was found that the use of antiretroviral regime with protease inhibitor was associated with a decrease in cardiac frequency, as seen in each group's cardiac frequencies: HIV+ with treatment group: 63.34 bpm, treatment-naïve HIV positive: 79.77 bpm and control group: 69.3 bpm. Conclusion We did not find correlation between HIV infection, the use of protease inhibitor-containing antiretroviral regime and QT interval prolongation in males, as opposed to females, where it was shown that QT interval duration is longer in the HIV+ treatment-naïve group. It was also observed that the use of protease inhibitor-containing antiretroviral regime was associated with a decrease in cardiac frequency. Funding Acknowledgement Type of funding source: None

Three-dimensional analysis of the heart function and effect cholinergic agonists in the cockroach Gromphadorhina portentosa

Many relevant aspects of mammal’s cardiac physiology have been mainly investigated in insect models such as Drosophila melanogaster and Periplaneta americana. Cardiac function has been poorly studied in the cockroach Gromphadorhina portentosa, which has some advantages for experimental purposes such as an easier culture, bigger organs and a robust physiology. On the other hand, the study of cardiac physiology in insects has been largely improved since the arrival of digital imaging technologies for recording purposes. In the present work, we introduce a methodology of video recording coupled to an isotonic transducer for a three-dimensional analysis of the heart and intracardiac valves of G. portentosa. We used this methodology for assessing the physiological responses of the cockroach heart upon the application of different cholinergic neurotransmitters (acetylcholine, nicotine and muscarine). We recorded in detail the relationship between intracardiac valves movement, hemolymph flow, diastole and systole. Acetylcholine and nicotine induced a biphasic effect on the cardiac frequency. Acetylcholine increased the diastolic opening. Nicotine at high concentration caused paralysis. Muscarine induced no major effects. These findings suggest a combined action of cholinergic agonists for a finely tuned the cardiac frequency, intracardiac valves function and cardiac cycle.

Electrocardiogram Fiducial Points Detection and Estimation Methodology for Automatic Diagnose

Background:The estimation of fiducial points is specially important in the analysis and automatic diagnose of Electrocardiographic (ECG) signals.Objective:A new algorithm which could be easily implemented is presented to accomplish this task.Methods:Its methodology is rather simple, and starts from some ideas available in the literature combined with new approachs provided by the authors. First, aQRScomplex detection algorithm is presented based on the computation of energy maxima in ECG signals which allow the measurement of cardiac frequency (in beats per minute) and the estimation of R peaks temporal positions (in number of samples). From these ones, an estimation of fiducial points Q, S, J, P and T waves onset and offset points are worked out, supported in a simple modified slope method with constraints.The location process of fiducial points is assisted with the help of the so called curvature filters, which allow to improve the accuracy in this task.Results:The procedure is simulated in Matlab and GNU Octave by using test signals from the MIT medical database, Cardiosim II equipment patterns and synthetic signals developed by the authors.Conclusion:One of the novelties of this work is the global strategy. Also, another significant innovation is the introduction of the curvature filters. We think this concept will prove to be a useful tool in signal processing, not only in ECG analysis.