Light and electron microscopic study of the effect of low estroger level on the heart of adult female rats

Oestrogen has first been employed as a contraceptive either alone or combined with other hormone during the female reproductive life. It is known that its blood level decreases with age, when its withdrawal causes health problems. The morbidity and mortality from cardiovascular diseases and other health problems increase at the time this steroid is declining, hence hormonal replacement is recommended. Induction of low blood oestrogen level is attained through the administration of the non-steroidal antioestrogenic compound tamoxifen citrate [0.2 mg/100 gm b.w.]. Oestrogen compensation was achieved by the oestrogenic compound oestradiol benzoate [0.6 mg/100 gm b.w.], all administered subcutaneously three times weekly for 12 weeks. Forty adult female rats were divided into four groups often animals, they received saline solution [control], antioestrogen alone, oestrogen and its antagonist and oestrogen alone. The cardiac tissues were dissected out at the end of the experimental period, processed and stained with hematoxylin and eosin for light microscopy. Parallel tissue specimens were processed for E.M. study. The results have revealed many changes after the antioestrogen administration. Specifically, interstitial edema, splitting, destruction and necrosis of the myocardial fibers and cellular infiltration have been detected. At E.M. level, there have been marked destruction of myocardial filaments, cytoplasmic degeneration and swollen and destructed mitochondria. It was apparent that when oestrogen was administered with its antagonist, had reduced the untoward effects which were demonstrated in the cardiac tissues when exposed to the antioestrogen alone, although hemorrhagic areas, vascular congestion and endothelial cytoplasmic vaculations have been detected. Meantime, oestrogen alone did show mild adverse effect. This would explain the cardioprotectivity inherent in oestrogen whenever no contraindication for its employment is eminent

study of the effect of fentanyl on haemodynamic status in experimentally preconditioned myocardium of anaesthetized cats

This work is an experimental trial to study the effect of fentanyl on the preconditioned myocardium when exposed to ischemia. Experiments were carried out on 18 cats in vivo. The cases were classified equally into: Group I [preconditioned group] subjected to two 5-minute occlusions [with 20 minutes apart] of LAD followed by prolonged occlusion for 25 minutes [occlusion [3]]. Group II subjected to IV fentanyl in a dose of 150 mug/kg followed by 100 mug/kg/hour. In group III, while fentanyl was given as in group II, cats were subjected to preconditioning and ischemia as in group I. Arterial blood pressure, heart rate and ST segment changes were recorded in each group. The results showed that during occlusion [3], the heart rate dropped by 32% in group III vs 23.6% in group I. The mean systolic and diastolic blood pressure showed no significant change between the two groups. The ST segment elevation decreased from 1.7 +/- 0.35 in group I to 0.1 +/- 0.08 mv in group III. So, fentanyl seemed to have a protective effect on the ischemic myocardium that is reflected in stabilization of the hemodynamic status of the anesthetized cats

Experimental study of the effects of pipecuronium, atracurium and pancuronium on cardiovascular system

The present work was undertaken to study the effects of pipecuronium, atracurium and pancuronium on isolated perfused rabbit heart, isolated rabbit atrium and on carotid arterial blood pressure as well as ECG changes with each drug administration. The results demonstrated that pipecuronium in a dose of 100 mug/kg b. wt. had no significant effect on heart rate and carotid arterial blood pressure of anesthetized cat. Atracurium [150 mug/kg b. wt.] produced 7.5% increase in basal heart rate and short lasting drop of arterial blood pressure lasting for approximately 1-1.5 min. followed by rapid recovery. Pancuronium [100 mug/kg b. wt.] increased heart rate by about 15.5% [p <0.05] and long lasting hypotension lasted for approximately 4-5 min. With gradual recovery to the pre-injection level. Pipecuronium and pancuronium produced no change in isometric contraction of rabbit atria in concentration range [5-20 mug/ml]. However, atracurium in concentrations of 30, 60, 120 mug/ml produced dose-dependent increase in contraction of rabbit atria without any effect on heart rate. When the chronotropic effects of three drugs were investigated using acetylcholine as an agonist on isolated perfused rabbit heart, it was found that pancuronium, but not pipecuronium and atracurium, produced a significant degree of antagonism to the bradycardia produced by acetylcholine. It was concluded that pipecuronium appears to be a suitable replacement for pancuronium for the production of muscular relaxation of relatively long duration in patients in whom elevation of heart rate has to be avoided. Also, the vagolytic effects of pancuronium are desirable, especially when counter acting the bradycardiac tendency of large doses of fentanyl. And that the transient hemodynamic effect of atracurium is probably of little clinical significance in the healthy patient

Effects of superoxide dismutase on isoprenaline-induced damage to rat myocardium

This study was designed to investigate the effects of the enzyme superoxide dismutase [SOD] on isoprenaline- induced damage to rat myocardium. Four groups of rats were used. One group received isoprenaline [ISO] alone, another group received SOD alone, the third group with both ISO and SOD, the last group served as a control. Results have shown that SOD attenuated the biochemical and histopathological chances induced by ISO on myocardium; mainly by reducing the depletion of adenosine triphosphate [ATP] and glycogen, and reducing the serum malondialdehyde [MDA] level. It is concluded from this study that the enzyme SOD could play an important role in reducing myocardial damage associated with isehaemia

Propafenone in experimentally induced acute myocardial infarction

In the present work, the effect of propafenone on experimental acute myocardial ischemia induced by either total left coronary artery [LCA] ligation [persistent and transient for 30 and 60 minutes] or by s.c. injection of isoprenaline [300 mg/kg] was investigated in albino rats. Propafenone was given as a single selected for evaluation of the severity of ischemia and the effect of propafenone were the voltage of T-wave, the heart rate, the CK-MB enzyme serum level and the percent of infarct area. In addition, the effect of propafenone on the coronary outflow in vitro was, also, investigated on the rabbit heart. The present work demonstrated that propafenone produced significant decrease in almost all examined parameters, when it was given before or after induction of ischemia. However, pretreatment with propafenone produced significantly greater effects as compared with those produced when the drug was administered after induction of ischemia. Such finding suggested a protective rather than a curative effect for propafenone against myocardial damage caused by ischemia. Investigating the effect of propafenone on the isolated perfused rabbit heart revealed a significant increase in the coronary outflow, which could, in part, explain the cardioprotective effect of this drug in myocardial ischemia

Efectos del dietilaminoetmozin (etazin) sobre la corriente de calcio en el miocardio auricular / Effects of diethylaminoethmozine (ethacizine) on Ca current in atrial myocardium

Se estudiaron los efectos del dietilaminoectmozin (etacizin) sobre la corriente de Ca en trabéculas auriculares de rana. El etacizin provocó una reducción en la corriente de Ca dependiente de la dosis (1, 2 y 5 *g/mL y muestra un mayor por ciento de inhibiciòn o potenciales positivos. Esta reducciòn en la corriente de Ca estuvo asociada a un desplazamiento en la curva de disponibilidad de la corriente de Ca hacia potenciales màs negativos, lo cual implicó un mayor grado de inactivaciòn. Esta acciòn inhibitoria del etacizin sobre la corriente de Ca mostró, además, dependencia con la frecuencia de estimulación. Se concluye que el etacizin tiene efectos importantes sobre la corriente de Ca, los cuales pueden dar como resultado un inotropismo negativo

Effect of captopril on serum electrolytes [Na+, K+ and Ca++], total lipids, cholesterol and beta lipoproteins as well as on sodium and potassium levels of the myocardium in rats

Captopril is an antihypertensive agent which was designed to inhibit the action of converting enzyme responsible for generating angiotensin II. In the present study, estimation of serum electrolytes [Na+, K+ and Ca++], total lipids, cholesterol and beta-lipoproteins under the effect of one month daily oral administration of different graded doses of captopril in rats, together with its effect on sodium and potassium level of the myocardium of the same rats were carried out. Captopril produced significant dose dependent decrease in the serum sodium level. It caused significant dose dependent increase in the serum potassium level. On the total lipids, captopril resulted in significant dose dependent reduction of serum level. On the other hand, the drug did not affect significantly the other aforementioned parameters

Efectos de sulfinpirazona sobre tejidos miocárdicos con estimulación eléctrica o sin ella / Effects of sulfinpyrazone on myocardial tissues with or without electrical stimulation

Se estudiaron in vitro los efectos del ácido arquidónico (AAq) y sulfinpirazona (SP) sobre miocardio de rata "suquía" de 240+ ou - 10g. Bandas auriculares y ventriculares fueron instaladas en solución Krebs-bicarbonato a 36 + ou- 1-C, registrado tensión contráctil isométrica (TC) y niveles de malonato (MDA), con electroestimulación o sin ella (1,6 Hz), AAq (2,5 microng/ml) y SP (375, 750, 1.500 y 3.000 microng/ml). AAq deprimió 100% de la TC de ambos preparados, registrándose en tiempos variables (9 a 17 min.) recuperación espontánea en la mayoría de los casos, aunque sin recuperar los valores iniciales. La reactividad eléctrica aumentó en el tejido auricular, pero no en el ventricular. Los efectos de SP dependen de la concentración; 375 microng/ml bajan la TC auricular 87 + ou - 7,3%. La respuesta ventricular a esa dosis fue variable, aunque la TC disminuyó en 61,5% de los preparados; 3 mg/ml son homogéneamente estimulantes. La reactividad eléctrica disminuye con SP. La concentración de MDA en los preparados auriculares cayó muy significativamente (p<0,001) después de SP. En los ventriculares se observó disminución de menor magnitud, también significativa (p<0,02). La suma algebraica de caída y recuperación de TC de los preparados auriculares después de dar SP, da un porcentaje de pérdida similar al descenso del malonato (+ ou - 25%). Se sugiere que: a) AAq deprime el miocardio por acción directa sin descartar alguna transformación inmediata en derivados activos. b) La SP inhibiría distintas enzimas en función de las dosis. c) El MDA parece ser consumido por el tejido miocárdico o metabolizado en el medio. Se plantean explicaciones alternativas para este fenómeno y su relación con el mecanismo de acción de la sulfinpirazona

Cardiotoxicidad de la adriamicina: estudio farmacológico e histopatológico en ratas / Cardiotoxicity of adriamycin: pharmacological and histopathological study in rats

Trabajos recientes mostraron una disminución en la respuesta adrenérgica miocárdica en la insuficiencia cardíaca. Por ello evaluamos los efectos de un tratamiento subagudo con ADM sobre la actividad cardíaca de noradrenalina (NA) e ISOproterenol (ISO). Ratas Wistar de ambos sexos (300-400 g) recibieron ADM 4 mg/kg i.v. en los días 1 y 8. Los controles fueron inyectados con solución fisiológica. El día 21 se sacrificaron los animales y se estudió la histopatología cardíaca. Mediante curvas concentración-respuesta, se evaluó la actividad cronotrópica (CRONO) de NA en la aurícula dreecha aislada (Krebs-carbogeno, 37 grados centígrados). El efecto inotrópico (INO) de NA e ISO fue estudiado en aurícula izquierda, estimulada a 3 Hz. Cada grupo experimental incluyó 4-6 ratas. Las curvas concentración-respuesta a NA revelaron: 1) Desplazamiento a la derecha para CRONO en el grupo ADM (ED 50:7,1 + ou - 1,7. 10-7M versus 3,0 + ou - 1,4.10-8 M en controles; p<0,01).2) Un fenómeno similar para INO (ED 50:2,8 + ou - 0,2.10-7 M con ADM versus 2,3 + ou - 0,7.10-8 en controles; p<0,01). Con ISO, se obtuvieron resutados similares en INO (ED 50:1,8 + ou - 0,7.10-8 M con ADM, versus 3,6 + ou - 1,7.10-10 M en controles; p<0,001). Las ratas tratadas con ADM presentaron ascitis, derrame pleural y lesiones miocárdicas (miocitolisis, vacuolización, infiltración linfocitaria), no así las ratas control. El tratamiento subagudo con ADM deprime la respuesta beta-adrenérgica miocárdica en ratas. Este fenómeno se acompaña de signos histopatológicos de daño cardíaco. El presente modelo puede ser útil para evaluar posibles agentes protectores de la cardiotoxicidad promovida por la ADM

Avaliaçäo do potencial cardiotóxico do VP-16 através de um modelo experimental utilizando ratas albinas: discussäo de achados anátomo-patológicos / Evaluation of cardiotoxic potential of VP-16 by an experimental model using albine rats: discussion of the anatomopathological findings

A existência de relatos ocasionais de cardiotoxicidade pelo VP-16 motivou os autores a realizarem este estudo. Para tal, um modelo experimental utilizando dois grupos de ratas Albinas (grupo A e grupo B) foi idealizado. Os animais do grupo A foram divididos em sub-grupos de 10 (G1, G2, G3, G4 e G5), sendo tratados com VP-16-213 5mg/kg de peso por via intrapetorineal em ciclos semanais pelo prazo de oito ciclos. O grupo B recebeu soluçäo de cloreto de sódio isotônico (0,9%) pelo mesmo espaço de tempo. Os animais do grupo A foram sacrificados a intervalos de 14 dias, segundo a ordem dos sub-grupos tratados. Os animais do grupo B foram sacrificados ao término do experimento. A avaliaçäo anatomopatológica dos coraçöes de animais do grupo A näo diferiu significativamente entre os sub-grupos, a despeito das doses crescentes da droga. Quando estes achados foram confrontados com os do grupo B, näo foram detectadas diferenças significativas entre as amostras (P menos de 0.05). Isto permite aos autores concluir pela ausência de cardiotoxicidade pela droga, o que sugere que as descriçöes prévias de literatura devam decorrer de fatores näo-associados ao uso de droga