Intestinal absorption characteristics of Polygonum orientale extract in normal and isoproterenol-induced myocardial ischemia model rats via everted intestinal sac models / 中国中药杂志

The present study is to investigate the absorption characteristics of the main components in Polygonum orientale extract in normal and isoproterenol-induced myocardial ischemia model rats with everted intestinal sac models. Intestinal sac fluid samples were collected in different part of intestine(duodenum, jejunum, ileum, colon) at different time after administration of different concentration of P. orientale extract(5.0,10.0, 20.0 mg·mL~(-1)). An UPLC-TQD method was employed for the determination of six components including orientin, isoorientin, vitexin, protocatechuic acid, kaempferol-3-O-β-D-glucoside and quercitrin in the intestinal sac samples. The absorption rate and cumulative absorption were calculated to analyze the intestinal absorption characteristics of six components in normal and myocardial ischemia model rats. The P-glycoprotein(P-gp) inhibitor was applied to investigate influence of intestinal absorption of six components in P. orientale extract. The results showed that the main absorption sites were concentrated on the duodenum at low concentration, while they were the colon at the medium concentration and the ileum at high concentration in control groups. In the condition of myocardial ischemia model, the main absorption sites focus on the ileum and jejunum at low concentration; the main absorption sites were in the ileum at the medium concentration and main absorption sites were the duodenum and ileum at high concentration. Compared with the normal group, the absorption rate and cumulative absorption of the six components significantly decreased in the model group. P-gp inhibitor markedly increased the absorption rate and cumulative absorption of six components in the model group, inferring that the 6 components may be the substrates of P-gp, and the mechanism needs further study. In this study, it is revealed that the six components of P. orientale extract can be absorbed into the intestinal sac, and it is an effective method to assess the intestinal absorption characteristics of P. orientale extract through everted intestinal sac model, providing data support for the clinical application and further development of P. orientale.

A literature review on cardiovascular risk in human immunodeficiency virus-infected patients: implications for clinical management

INTRODUCTION: In recent years, there has been growing concern about an increasing rate of cardiovascular diseases in human immunodeficiency virus-infected patients, which could be associated with side effects of highly active antiretroviral therapy. It is likely that the metabolic disorders related to anti-human immunodeficiency virus treatment will eventually translate into a increased cardiovascular risk in patients submitted to such regimens. OBJECTIVE: To evaluate if human immunodeficiency virus-infected patients receiving highly active antiretroviral therapy are at higher risk of cardiovascular diseases than human immunodeficiency virus infected patients not receiving highly active antiretroviral therapy, or the general population. RESEARCH DESIGN AND METHODS: We conducted a computer-based search in representative databases, and also performed manual tracking of citations in selected articles. RESULT: The available evidence suggests an excess risk of cardiovascular events in human immunodeficiency virus-infected persons compared to non-human immunodeficiency virus infected individuals. The use of highly active antiretroviral therapy is associated with increased levels of total cholesterol, triglycerides, low-density lipoprotein and morphological signs of cardiovascular diseases. Some evidence suggested that human immunodeficiency virus-infected individuals on highly active antiretroviral therapy regimens are at increased risk of dyslipidemia, ischemic heart disease, and myocardial infarction, particularly if the highly active antiretroviral therapy regimen contains a protease inhibitor. CONCLUSION: Physicians must weigh the cardiovascular risk against potential benefits when prescribing highly active antiretroviral therapy. Careful cardiac screening is warranted for patients who are being evaluated for, or who are receiving highly active antiretroviral therapy regimens, particularly for those with known underlying cardiovascular risk factors. A better understanding of the molecular mechanisms responsible for increased risk of cardiovascular diseases in human immunodeficiency virus-infected patients will lead to the discovery of new drugs that will reduce cardiovascular risk in human immunodeficiency virus-infected patients receiving highly active antiretroviral therapy.

In vivo and in vitro studies on the antioxidant activity of sea cucumber aqueous extract against isoproterenol-induced myocardial injury in a rat model

The present study was undertaken to evaluate the cardiopreventive activity of the aqueous extract of sea cucumber body wall against isoproterenol-induced cardiac injury in rats. Isoproterenol a synthetic catecholamine and beta-adrenergic agonist, which causes severe oxidative stress-induced myocardial injury. HPLC analysis of the sea cucumber aqueous extract revealed the presence of some active phenolic components with antioxidant activity, such as pyrogallol, rutin, chlorogenic acid, ascorbic acid, catechin, coumaric acid, cinnamic acid, and ellagic acid. Subchronic oral administration of sea cucumber extract [14.4mg/Kg b.w.] to normal rats thrice weekly for 8 consecutive weeks did not exert any toxic side effects. whereas enhanced the cardiac reduced glutathione level and catalase activity, and in contract reduced serum low density liporprotein-cholestrol level. On the other hand, pretreatment of rats with the sea cucumber extract for 8 weeks before being intoxicated with 2 subcutaneous injections of isoproterenol normalized serum levels of total CK, CK-MB activity, total cholesterol. triglycerides and high-density lipoprotein-cholesterol, as well as cardiac glutathione peroxidase and catalase activities. In vitro antioxidant studies on the sea cucumber extract have shown a moderate scavenging activity for NO radical and iron chelating activity, as well as a weak inhibition of lipid peroxidation. In addition, histopathological examination of H and E stained myocardium sections of the left ventricle showed that pretreatment of isoproterenol-intoxicated rats with sea cucumber extract caused a substantial attenuation in the degenerative cellular changes induced by isoproterenol

Avaliação da perfusão e função miocárdicas em vítimas de escorpionismo utilizando o Gated-SPECT / Assessment of myocardial perfusion and function in victims of scorpion envenomation using Gated-SPECT

FUNDAMENTO: O choque cardiogênico e o edema agudo de pulmão são as principais causas de óbito em pacientes com escorpionismo, cujo mecanismo fisiopatológico ainda é controverso. OBJETIVOS: Investigar a correlação entre os distúrbios da perfusão miocárdica e a função contrátil do ventrículo esquerdo, em vítimas de escorpionismo. MÉTODOS: Quinze pacientes submeteram-se à cintilografia de perfusão miocárdica sincronizada com ECG (Gated SPECT), dentro de 72 horas e 15 dias após o acidente escorpiônico. As imagens foram analisadas visualmente por escore semiquantitativo de perfusão (0 = normal, 4 = ausente) e mobilidade (0 = normal, 4 = acinético), utilizando modelo de 17 segmentos. Para cada paciente foram calculados escores somados de perfusão (ESP) e mobilidade (ESM). A fração de ejeção (FEVE) foi calculada por software comercialmente disponível. RESULTADOS: Na avaliação inicial, 12 dos 15 pacientes apresentaram alterações da contratilidade e da perfusão miocárdica. O ESP foi de 12,5 ± 7,3, o ESM de 17,0 ± 12, 8 e a FEVE de 44,6 ± 16,0 por cento. Houve correlação positiva entre o ESP e o ESM (r = 0,68; p = 0,005) e negativa entre o ESP e a FEVE (r = -0,75; p = 0,0021). Os estudos de seguimento mostraram recuperação da contratilidade global (FEVE de 68,9 ± 9,5, p = 0,0002), segmentar (ESM 2,6 ± 3,1, p = 0,0009) e da perfusão (ESP 3,7 ± 3,3, p = 0,0003). A melhora da FEVE correlacionou-se positivamente com a melhora do ESP (r = 0,72; p = 0,0035). CONCLUSÕES: Alterações perfusionais miocárdicas são comuns no envenenamento escorpiônico e correlacionam-se topograficamente com a disfunção contrátil. A recuperação da contratilidade correlaciona-se com a reversibilidade dos defeitos perfusionais. Estes achados sugerem a participação de alterações perfusionais miocárdicas na fisiopatologia desta forma de insuficiência ventricular aguda. (Arq Bras Cardiol 2010;94(4): 444-451)

BACKGROUND: Cardiogenic shock and acute pulmonary edema are the major causes of death of patients with scorpion envenomation, whose pathophysiological mechanism remains controversial. OBJECTIVE: To investigate the correlation between myocardial perfusion abnormalities and left ventricular contractile function in victims of scorpion envenomation. METHODS: Fifteen patients underwent ECG-gated myocardial perfusion scintigraphy (gated SPECT) within 72 hours of, and 15 days after scorpion envenomation. Images were analyzed by means of a semi-quantitative visual perfusion score (0 = normal, 4 = absent) and motion score (0 = normal, 4 = akinesia), using the 17-segment model. Summed perfusion (SPS) and summed motion (SMS) scores were calculated for each patient. Ejection fraction (LVEF) was calculated by a commercially available software. RESULTS: At baseline, 12 out of the 15 patients presented abnormal myocardial perfusion and contractility. Mean values of SPS, SMS and LVEF were 12.5 ± 7.3, 17.0 ± 12.8, and 44.6 ± 16.0 percent, respectively. A positive correlation between SPS and SMS (r = 0.68; p = 0.005) and negative correlation between SPS and LVEF (r = -0.75; p = 0.0021) were found. The follow-up studies showed recovery of global contractility (LVEF of 68.9 ± 9.5, p = 0.0002), segmental contractility (SMS of 2.6 ± 3.1, p = 0.0009) and perfusion (SPS of 3.7 ± 3.3, p = 0.0003). Improvement of LVEF correlated positively with improvement of SPS (r = 0.72; p = 0.0035). CONCLUSIONS: Myocardial perfusion abnormalities are common in scorpion envenomation and correlate topographically with the contractile dysfunction. Recovery of contractility correlates with reversibility of perfusion defects. These findings suggest the participation of myocardial perfusion abnormalities in the pathophysiology of this form of acute ventricular failure. (Arq Bras Cardiol 2010;94(4): 418-425)

The Thai anesthesia incident monitoring study (Thai AIMS): an analysis of perioperative myocardial ischemia/infarction.

OBJECTIVES: To analyze the clinical course, outcome, contributing factors and factors minimizing the incidents of perioperative myocardial ischemia or infarction (PMI) from Thai AIMS study. MATERIAL AND METHOD: The present study was a prospective multicenter study. Data was collected from 51 hospitals in Thailand during a six-month period. The participating anesthesia provider completed the standardized incident report form of the Thai AIMS as soon as they found the PMI incident. Each incident was reviewed by three peer reviewers for clinical courses, contributing factors, outcome and minimizing factors of PMI. RESULTS: From the Thai AIMS incident report, the authors found 25 suspected PMI cases which was 0.9% of the 2,669 incidents reported in the present study. Most of the PMI occurred in elective cases (84%) and orthopedic procedures (56%). The majority of PMI was reported from the patients undergoing general anesthesia (72%). Suspected PMI occurred mostly during operations (56%). New ST-T segment change was detected in 92% of these patients. The most common immediate outcome of PMI was major physiological change (88%). The most common management effect of PMI was unplanned ICU admission (64%); the others were prolonged ventilatory support (12%) and prolonged hospital stay (16%). Four patients (16%) died after the suspected PMI. Most of the events occurred spontaneously and were unpreventable (80%). Patient factors (100%), anesthesia factors (72%), surgical factors (32%) and system factors (8%) were all judged as a precipitating factor for PMI. Human factors were the most common contributing factors which included poor preoperative evaluation, inexperience and improper decision. The three most common factors minimizing the adverse incidents included prior experienced, high awareness and experienced assistance. The recommended corrective strategies were guideline practice, quality assurance activity, improvement of supervision and additional training. CONCLUSION: Perioperative myocardial ischemia/infarction was infrequent but may be lethal. Patient factors were the most common precipitating cause. The morbidity and mortality could be reduced by high quality preoperative evaluation and preparation, early detection and appropriate treatment. Guideline practice, quality assurance activity, improvement of supervision and additional training were suggested corrective strategies.

Aprotinin reverses ECG abnormalities induced by Mesobuthus tamulus concanesis, Pocock venom in adult rats.

The kinins are implicated in the pathogenesis of scorpion envenomation. Therefore, this study was carried out to examine the involvement of kinins for the ECG abnormalities induced by M. tamulus concanesis, (BT) venom in anaesthetized rats. ECG was recorded using needle electrodes with limb lead II configuration. The PR interval, QRS wave pattern, QRS duration, ST segment and heart rate were examined in saline only, venom alone, and venom after aprotinin groups. BT venom (5 mg/kg) produced heart block of varying degree and ischemia-like changes in ECG wave pattern and the animals died within 30 min after exposure to venom. In aprotinin pretreated animals, the initial ECG changes produced by venom persisted, but after 15 min the ECG pattern improved and the animals survived for the entire period of observation (120 min). The results indicate that aprotinin protected the rats against the cardiotoxicity induced by BT venom.

Efeitos cardiovasculares da anestesia local com vasoconstritor durante exodontia em coronariopatas / Cardiovascular effects of local anesthesia with vasoconstrictor during dental extraction in coronary patients

OBJETIVO: Avaliar a ocorrência de variáveis detectoras de isquemia miocárdica, durante ou após o tratamento odontológico, sob anestesia com vasoconstritor (adrenalina). MÉTODOS: Foram incluídos 54 pacientes coronariopatas submetidos a exodontia sob anestesia local com ou sem vasoconstritor, divididos em dois grupos (sorteio por envelope): grupo I, composto por 27 que receberam anestésico com vasoconstritor; e grupo II, composto por 27 que receberam anestésico sem vasoconstritor. Todos os pacientes foram submetidos a monitoração eletrocardiográfica com Holter por 24 horas, a Doppler-ecocardiografia realizada antes e após intervenção odontológica, e a dosagem dos marcadores bioquímicos antes e 24 horas após a exodontia (creatina cinase fração MB [CK-MB] massa, CK-MB atividade e troponina T). A freqüência cardíaca e a pressão arterial nas fases pré-anestesia, pós-anestesia e pós-exodontia também foram aferidas. A Doppler-ecocardiografia teve como objetivo avaliar a contratilidade segmentar do ventrículo esquerdo e a eventual ocorrência de insuficiência mitral. Em todos os casos foi mantido o protocolo farmacológico habitual prescrito pelo cardiologista. RESULTADOS: Três pacientes do grupo I apresentaram depressão do segmento ST (1,0 mm) durante a aplicação da anestesia, dois outros pacientes do mesmo grupo tiveram elevação da CK-MB massa, e em nenhum caso foi verificada presença de isquemia avaliada pelos demais métodos. Não houve registro, neste estudo, de precordialgia, arritmias e ocorrência ou agravamento de hipocontratilidade segmentar do ventrículo esquerdo ou insuficiência mitral. CONCLUSÃO: A exodontia praticada sob uso de anestesia com adrenalina 1:100.000 não implica riscos isquêmicos adicionais quando realizada com boa técnica anestésica e manutenção do tratamento farmacológico prescrito pelo cardiologista.

OBJECTIVE: To evaluate the occurrence of variables detecting myocardial ischemia during or after dental treatment under anesthesia with vasoconstrictor (epinephrine). METHODS: A total of 54 coronary patients undergoing dental extraction under local anesthesia with or without vasoconstrictor were included. They were divided into two groups (by drawing envelopes): group I (27 patients) using anesthetics with vasoconstrictor, and group II (27 cases) without vasoconstrictor. 24-hour Holter monitoring, Doppler-echocardiogram before and after dental intervention, and determination of biochemical markers (CK-MB mass, CK-MB activity, and troponin T) before and 24 hours after dental extraction were performed in all patients. Heart rate and blood pressure were also measured in the pre, post-anesthesia and post-dental extraction phases. Doppler echocardiography assessed left ventricular segmental contractility and the occasional occurrence of mitral regurgitation. The usual pharmaceutical treatment prescribed by the cardiologist was maintained in all cases. RESULTS: Three patients in group I presented ST-segment depression (1.0 mm) during administration of anesthesia; two other patients in group I had CK-MB mass elevation, and ischemia was not observed in any other case, as assessed by the other methods. No chest pain, arrhythmias, occurrence or worsening of left ventricular segmental hypocontractility or mitral regurgitation were observed in the study. CONCLUSION: Dental extraction performed under anesthesia with 1:100,000 epinephrine does not imply additional ischemic risks, as long as performed with good anesthetic technique and maintenance of the pharmacological treatment prescribed by the cardiologist.

Effect of long term oral administration of L-arginine on experimentally produced myocardial ischemia in rabbits.

L-arginine a semi essential amino acid and a precursor of nitric oxide (NO) was orally supplemented in diet (standard rabbit feed) of hypercholesterolemic (n=6) and normal rabbits (n=6) for 16 weeks. Myocardial ischemia was produced in both groups of rabbits by subcutaneous single bolus injection of isoproteronol. Severity of myocardial ischemia was assessed by estimating the serum CPK and AST levels after 6 hour of ischemia-reperfusion. The result suggests that severity of ischemia was lesser in the L-arginine primed hypercholesterolemic group.

Avaliação de modelo experimental de falência crônica isolada do ventrículo direito / Evaluation of experimental model of isolated chronic right ventricle failure

Os modelos experimentais de falência do ventrículo direito (VD) descritos são de difícil execução, por envolverem procedimentos cirúrgicos complexos e dispendiosos, com alta mortalidade e baixa reprodutividade. Também são raros aqueles que promovem falência ventricular exclusiva do ventrículo direito. Com o objetivo de simular a situação clínica de falência ventricular exclusiva do VD, desenvolvemos um modelo experimental de falência crônica isolada do VD, feito através da injeção de etanol intramiocárdico. A disfunção do VD foi induzida em treze cães adultos, através de múltiplas injeções de etanol a 96% (dose total 1ml/kg), na via de entrada e na porção trabecular do VD. Foram analisados parâmetros hemodinâmicos, metabólicos e ecocardiográficos, em condições basais e após indução da falência. Os animais foram mantidos vivos por um período de 14 dias, após o qual foram reoperados e mortos para análise morfológica dos corações. As pressões foram aferidas na artéria femoral, átrio esquerdo (AE), átrio direito (AD), tronco pulmonar (TP) e VD. O fluxo sanguíneo foi medido na aorta e no tronco pulmonar. Na primeira operação, os dados hemodinâmicos foram registrados antes e imediatamente após a indução da falência do VD. Estes parâmetros também foram coletados na reoperação (14 dias pós-indução da falência). Amostras de sangue arterial e venoso foram colhidas simultaneamente ao registro dos parâmetros hemodinâmicos para avaliação dos gases sanguíneos e dosagem de lactato. Foram feitas avaliações ecocardiográficas no pré-operatório, no sexto e no 130 dia pós-operatório (PO). Houve uma mortalidade de 15,4% (2/13). Observou-se uma queda significativa no débito cardíaco pulmonar após a indução da falência e na reoperação (14º PO), quando comparado aos valores medidos no momento basal (p=0,002). Esta queda do desempenho ventricular direito ocasionou um aumento nos valores do lactato venoso, quando comparados os valores basais contra aqueles do pós infusão...

Isolated chronic right ventricle (RV) dysfunction is difficult to achieve in experimental models, and sometimes very expensive. Some models require complex surgical procedures, with a high mortality rate and low reproducibility. In order to simulate the clinical status of RV failure, we have developed an experimental model of chronic RV failure by injecting local intramyocardial ethanol 96%. A severe RV dysfunction was induced in 13 mongrel dogs by means of multiple intramyocardial injections of ethanol 96% (total dose of 1ml/kg), in the inlet and trabecular portions of the RV. The hemodynamics, metabolic and ecocardiografic parameters were evaluated at baseline condition and after RV failure. The animals were followed for a 14-day period. After that, they were reoperated for pressure measurements, taken from femoral artery, left atrium (LA), right atrium (RA), RV and main pulmonary artery (PA). Blood flow was measured in the aorta (AO) and PA. Metabolic parameters were assessed simultaneously to pressure measurements, with arterial and venous blood samples withdrawn for gas and lactate analysis, and then, they were killed for morphological evaluation of the heart. All the animals were submitted to echocardiographic evaluation before the first operation, on sixth and on de 13th postoperative day. The mortality rate was 15,4% (2/13). There was a significant decrease in the pulmonary blood flow after RV failure induction (p=0,0018), as well as in the reoperation (p=0,002), as compared to baseline. This decrease in RV performance caused an increase in the venous lactate level, when baseline values are compared with pos infarction values (p=0,001) and reoperation (p=0003). The echocardiografic findings revealed an increased RV diastolic volume on the 6th (p=0,0001) and 13th postoperative day (p=0,0084), as compared to baseline values. Conversely, there was a significant decrease in the RV ejection fraction on the 6th and 13th postoperative day, when compared...

Electrocardiographic abnormalities among arsenic-exposed persons through groundwater in Bangladesh.

This study was carried out among arsenic-exposed and non-exposed people of Bangladesh to assess and compare their cardiac status based on electrocardiographic (ECG) findings. For the purpose of the study, participants were included in three groups: arsenic-exposed persons with arsenicosis (arsenicosis group), arsenic-exposed persons without arsenicosis (non-arsenicosis group), and persons not exposed to arsenic (non-exposed group). Each group included 50 respondents. In this study, no significant difference in heart rate, rhythm, axis, and pulse rate interval was detected among the arsenicosis, non-arsenicosis and non-exposed groups. A significant difference in corrected QT interval between the arsenicosis and the non-exposed group (p<0.05) was observed. On the contrary, no statistically significant difference in corrected QT interval between the non-arsenicosis and the non-exposed group was found. Abnormal QRS complex was found among 14%, 8%, and 2% of the arsenicosis, non-arsenicosis, and non-exposed groups respectively. ECG findings, indicative of left ventricular hypertrophy, ischaemic heart disease, and right bundle branch block, were high among the arsenicosis group. Overall, abnormal ECG findings were high (58%) among the respondents of the arsenicosis group and were highly significant (p<0.001). The findings revealed that there was a significant association between ECG abnormalities and arsenic exposure.

Myocardial ischemia induced by nebulized fenoterol for severe childhood asthma.

We examined for myocardial ischemia induced by continuous inhalation of fenoterol in children with severe acute asthma. Thirty children with severe acute asthma were evaluated for signs of myocardial ischemia when treated with 0.5 mg kg dose (maximum 15 mg) of inhaled fenoterol for one hour. The heart rate was measured before and after inhalation. Cardiac enzymes (creatine kinase, creatine kinase MB fraction and troponin levels) were measured at admission and 12 hours later. An EKG was recorded before inhalation was started and immediately after its completion to detect the presence of any evidence of myocardial ischemia. All patients developed significant increase in heart rate. Six patients showed EKG changes compatible with myocardial ischemia, despite normal enzyme levels. Patients with severe acute asthma show tachycardia and may show EKG changes of myocardial ischemia.

Acute myocardial ischemia following accidental intravenous administration of epinephrine in high concentration.

Inadvertent and accidental epinephrine overdose might result in potentially lethal complications. We present a case of acute epinephrine toxicity resulting in acute myocardial ischemia in a young boy with combined variable immunodeficiency syndrome who developed severe allergic reaction to intravenous immunoglobulin, and was subsequently given epinephrine by mistake intravenously rather than subcutaneously. He developed significant ischemic changes in standard 12-lead electrocardiogram, transiently raised cardiac enzymes, reduced left ventricular systolic function, pulmonary edema and pulmonary hemorrhage. It is suggested that special precautionary measures should be taken regarding the dose and the route while administering epinephrine to avoid mishaps.

Inhibidores de la COX-2, y eventos cardiovasculares a la luz de la historia del rofecoxib / COX-2 Inhibition and cardiovascular events on the light of the history of rofecoxib

En la presente nota se intenta poner en contexto el retiro del mercado del rofecoxib, por haberse asociado a un aumento de riesgo cardiovascular en pacientes que lo recibieron. Se describe el sustento fisiopatol¢gico de la asociaci¢n encontrada, as¡ como la evidencia existente acerca del uso de rofecoxib e infarto agudo de miocardio. Tambi‚n se explora la evidencia existente acerca de otros inhibidores de la COX-2, principalmente el celecocoxib. Se incluye una serie de consideraciones cl¡nicas para las recomendaciones terap‚uticas de celecoxib y otros coxibes en grupos de pacientes espec¡ficos, y se indica prudencia ante el uso de nuevas drogas de la familia que no cuentan con estudios de seguridad a largo plazo.

An experimental study on cardiotoxicity of aluminium phosphide.

Aluminium phosphide(AlP), a grain fumigant pesticide, was studied for its cardiotoxicity in anaesthetised rats. The hemodynamic and cardiac biochemical changes were investigated following intragastric administration of different doses of AlP (10, 20 and 40 mg). With 10 and 20 mg dose of AlP an immediate fall in BP was observed which recovered partially and stabilized for 10 minutes followed by a gradual fall till the animal died. However, with a higher dose (40 mg) there was no recovery in BP, instead the initial fall continued till the death of the animal. An increase in the heart rate was observed with 10 and 20 mg dose of AlP for 15 minutes which was followed by a marked fall till cardiac arrest ensued. On the other hand, 40 mg dose produced only a transient tachycardia followed by a prolonged bradycardia. ECG changes at all dose levels included initial tachycardia and ST segment elevation progressing to QRS broadening. However, marked conduction defects as evidenced by the ventricular ectopics were noticed only with 40 mg. The mean survival time dose dependently decreased with 10 mg(55 +/- 3 min), 20 mg(35 +/- 2 min) and 40 mg(18 +/- 2 min) of AlP. The cardiac glycogen, ATP and CP levels were significantly lowered in animals treated with 10, 20 and 40 mg of AlP. Higher levels of MDA in the cardiac tissue were observed with 10, 20 and 40 mg of AlP. Thus it is suggested that the deleterious effect of AlP on heart is mediated by both declined cellular metabolism of the myocardium as well as by necrosis of the cardiac tissue resulting in the release of reactive oxygen intermediates.

Utilidad de la medición del tiempo de relajación isométrica del ventrículo izquierdo con eco/Doppler durante la administración de dipiridamol o dobutamina como maniobra provocadora de isquemia miocárdica / Utility of the measurement of the isovolumetric relaxation time of the left ventricle with echo/Doppler during the administration of dipyridamole or dobutamine as triggering maneuver of myocardial ischemia

La isquemia miocárdica prolongada la relajación ventricular. El objetivo del estudio fue valorar las alteraciones en el tiempo de relajación isométrica del ventrículo izquierdo (TRIV), como parámetro de relajación ventricular global, medido con Doppler pulsado durante la administración de Dipiridamol o Dobutamina intravenosos. Estudiamos 58 pacientes con sospecha clínica o con cardiopatía isquémica demostrada, durante la administración de fármacos como maniobra provocadora de isquemia. Se dividieron en dos grupos: 22 pacientes en el grupo Dipiridamol, que se administró a dosis de 0.84 mg/kg en 10 min y 36 pacientes en el grupo de Dobutamina, administrada a dosis de 5, 10, 20, 30 y 40 mcg/kg/min en etapas de tres minutos. A todos los pacientes se les practicó coronariografía en el mismo internamiento. Las mediciones de las velocidades máximas E y A, así como el tiempio de desaceleración de la onda E y el tiempo de hemipresión del flujo mitral, no mostraron cambios significativos en ambos grupos. En los estudios positivos por criterios de alteración de la movilidad parietal, el TRIVI corregido para la frecuencia cardiaca (TRIVI/C) se incrementó hasta en 54 por ciento (p< 0.01), sobre los valores de control del mismo paciente en el grupo de Dipiridamol. En el grupo de Dobutamina, con los mismos criterios de positividad, el TRIVI/C se incrementó en 26 por ciento (p < 0.20). En la detección de obstrucción significativa proximal de la coronaria descendente anterior o de enfermedad trivascular, en el grupo de Dipiridamol, el incremento del TRIVI/C tuvo sensibilidad, el incremento del TRIVI/C tuvo sensibilidad (S), especificidad (E) y valor predictivo positivo (VPP) de 50 por ciento y 100 por ciento, respectivamente. En el grupo de Dobutamina, la S fue de 71 por ciento, la E de 60 por ciento y el VPP de 89 por ciento. Con ninguno de los fármacos se observó prolongación significativa del TRIVI/C en ausensia de alteraciones de la movilidad o sin acentuación de las alteraciones preexistentes. La medición del TRIVI/C, en estudios con maniobras farmacológicas provocadoras de isquemia, es un parámetro útil para diferenciar los resultados positivos de los negativos, agregado a los criterios de alteraciones segmentarias de la movilidad parietal

Do all calcium antagonists have a cardioprotective effect against isoproterenol induced myocardial necrosis in rats?

This study investigated and compared the possible protective effects of five Ca2+ entry blockers: Verapamil, nifedipine, diltiazem, flunarizine and amlodipine against isoproterenol-induced myocardial necrosis in rats. Fifty-six male albino rats were divided into seven equal groups. Group 1 served as control, group 2 received isoproterenol [85 mg/kg body wt. s.c.] for two days to produce myocardial necrosis, other groups received one of the following Ca2+ entry blockers for four successive days: verapamil [5 mg/kg body weight i.p.], nifedipine [0.2 mg/kg i.m.], diltiazem [10 mg/kg i.m.], flunarizine [30 mg/kg orally] and amlodipine [0.5 mg/kg orally]. On the third and fourth days of treatment, animals received isoproterenol in the dose mentioned above. Twenty-four hours later, blood samples were withdrawn from the orbital plexus for the determination of creatine phosphokinase [CPK] activity, aspartate aminotransferase [ASAT] and alanine aminotransferase [ALAT]. The post-ischemic survival rate [PISR] for each group was calculated. Isoproterenol caused a significant increase in CPK, ASAT and ALAT as compared to the control group, the PISR was 0%. Pretreatment with nifedipine, verapamil or diltiazem significantly reduced all the enzyme studied as compared to isoproterenol group, the PISR was 87.5% 75% and 75%, respectively. Amlodipine pretreatment reduced only ASAT, PISR was 25%. On the other hand, flunarizine pretreatment did not significantly change the enzyme studied, the PISR was 12.5%. The results suggested that nifedipine, verapamil and diltiazem have protective effects against isoproterenol-induced myocardial necrosis in rats and that flunarizine and amlodipine were free of these cardioprotective effects

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