Browsing by Author "Burger, Andries"

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    Cardiovascular effects of the alkaloid hippadine on the isolated perfused rat heart
    (Open Access Science Research Publisher, 2012) Mugabo, Pierre; Obikeze, Kenechukwu; Njagi, Angela; Burger, Andries; Dietrich, Danielle; Green, Ivan
    Crinum macowanii has been used extensively in traditional medicines for treatment of various illnesses such as oedema and ‘heart disease’. Previous studies of the crude bulb extracts on Langendorff perfused isolated rat hearts indicated a positive inotropic effect. The aim of this study was to isolate and characterize compound(s) from C. macowanii with cardiovascular effects similar to that observed with the crude extracts of the plant. The methanol extract of dried bulbs was extracted for alkaloids, and structural elucidation of the isolated alkaloid identified it as hippadine. The cardiovascular effects of hippadine was evaluated in vitro in isolated perfused rat hearts using the “double sided” working heart system. Perfusion with 0.5 μg/ml and 5.0 μg/ml hippadine in Krebs-Hanseleit buffer led to significant decreases in coronary flow, aortic output, cardiac output, systolic pressure, and heart rate, accompanied by increases in diastolic pressure. Hippadine exhibited a negative chronotropic and inotropic effect on the isolated rat heart and is responsible either partly or fully for the cardiovascular effects of C. macowanii.
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    Do HIV infection and antiretroviral therapy influence multidrug-resistant tuberculosis treatment outcomes?
    (Academic Journals, 2015) Mugabo, Pierre; Adewumi, A.O.; Theron, Danie; Burger, Andries; Van, Zyl L.
    The aim of this study was to find out whether human immunodeficiency virus (HIV)-infection and antiretroviral drugs influence multidrug-resistant (MDR)-tuberculosis (TB) treatment outcomes. The study compares MDR-TB treatment outcomes between HIV-positive and HIV-negative patients. It involved patients admitted for treatment of MDR-TB between 1 January 2004 and 31 December 2006. From 363 patients selected, 268 (177 males and 91 females) had MDR-TB and 95 patients (59 males and 36 females) were co-infected with HIV. Children in the HIV-negative group were 41 and 7 in the HIV-positive group. The HIV-infection was treated with Stavudine, Lamivudine and Efavirenz in 54 patients. Kanamycin, Ethionamide, Ofloxacin, Terizidone, Pyrazinamide and Ethambutol were used for MDR-TB treatment. In HIV-negative and HIV-positive patients MDR-TB treatment outcomes were, respectively as follows: 37 and 35% cure, 9 and 5% treatment failure, 20 and 25% lost to follow up, 11 and 17% mortality, 19 and 13% treatment completed, 6 and 5% transfer-out. The cure rate was 100% in children. In HIV-positive patients, MDR-TB cure rate was 35% in patients on ARVs and 34% in patients not receiving ARVs. The difference between these cure rates is not statistically significant (p-value = 0.79). The median (range) duration of ART before the start of MDR-TB treatment was 10.5 (1 to 60) months and did not influence MDR-TB treatment outcomes. In children, the full treatment was supervised in hospital. This could explain the 100% cure rate. Adults' treatment was supervised in hospital only during the intensive phase then followed up as out patients over 18 months. According to the results of this study, HIV-infection and antiretroviral therapy did not influence MDR-TB treatment outcomes.
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    Effects of Leonotis leonurus aqueous extract on the isolated perfused rat heart
    (Open Access Science Research Publisher, 2012) Mugabo, Pierre; Khan, Fatima; Burger, Andries
    The use the aqueous decoction of Leonotis leonurus (L. leonurus) (Ll) R. Br. (Lamiaceae) in the treatment of hypertension (HPT) in traditional medicine is well documented. The effect of the aqueous extract of LI on the blood pressure (BP) and heart rate (HR) has been investigated in normotensive rats. The aim of this study was to investigate the effect of Ll aqueous extract on the in isolated perfused rat heart (IPRH). Hearts were excised from male Wistar albino rats weighing 250-350g, aged less than 6 months. They were perfused at constant flow using the modified Langendorff perfused model of the heart. Effects of adrenaline on the left ventricular systolic pressure (LVSP), left ventricular end-diastolic pressure (LVEDP), left ventricular developed pressure (LVDP), heart rate (HR), cardiac work (CW) and coronary perfusion pressure (CPP) were compared to that of Ll. Adrenaline (1µM) significantly (p<0.05) increased the LVSP by 40.6%, the LVDP by 43.9%, the HR by 22.5% and the CW by 89.4%. Ll (1.0 mg/ml and 2.0 mg/ml respectively and significantly (p<0.01) increased the LVSP by 25.36 and 14.91, the LVDP by 29.40 and 14.88. Ll (1.0 mg/ml and 2.0 mg/ml) significantly produced a negative chronotropic effect. Both adrenaline and Ll aqueous extract did not have any significant effect on the LVEDP. Adrenaline resulted in positive inotropic and chronotropic effects. At low concentrations Ll produced a positive inotropic and a negative chronotropic effect. At the concentration of 2.0mg/ml Ll decreased all parameters to zero. At higher concentrations higher than 2.0mg/ml, Ll seemed to have toxic effects on the heart.
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    Inorganic ions in leonotis leonurus extract do not explain changes in isolated Wistar rat heart function
    (Open Access Science Research Publisher, 2011) Burger, Andries; Mugabo, Pierre; Henkel, Ralf; Green, Ivan
    Leonotis leonurus (L. leonurus) R. Br (Lamiaceae) is used by healers in South Africa. The present study was conducted to determine if the L. leonurus effect on isolated rat heart is due to ionic changes in the perfusion fluid.