Albert Amin Sader

Pré-condicionamento precoce da medula espinal isquêmica: pesquisa em coelhos

Early preconditioning of the spinal cord was investigated in rabbits, as an eventual protection mechanism, immediately before a 30 min ischemic period. Eight-seven New Zealand rabbits divided into 6 groups were assigned to the study. Ischemia of the spinal cord was induced by crossclamping (C) the abdominal aorta distal to the emergence of the left renal artery. Preconditioning was stimulated by short and sometimes repetitive ischemic periods, underlined in the text, and followed by different periods of reperfusion. Group I - Control: In 20 animals the aorta was crossclamped for 30 min. In two of them (10%) motricity and sensitivity of the hind-legs and tail were entirely restored; the other 18(90%) became paraplegic. Group II - Sham operation: 10 animals were operated as the ones in the previous group except for the fact that the aorta was not clamped. All of them (100%) had their sensitive and motor functions entirely restored. Group III - Preconditioning: 10 animals - (C) 1 min ® 15 min® (C) 30 min ® final reperfusion. All animals became paraplegic. Group IV - Preconditioning: 6 animals - (C) 1 min ® 5 min® (C) 2 min ® 5 min ® (C) 2 min ® 5 min ® (C) 30 min final reperfusion. Five rabgbits (83,33%) became paraplegic and 1 (16,66%) became monoplegic. Group V - Chlorpromazine: 20 animals were given chlorpromazine, intravenously, 2 mg/kg, 10 min before aortic crossclamping. Eleven animals (55%) had their sensitive and motor functions reestablished and 9 (45%) became paraplegic. Group VI - Clorpromazine + preconditioning: 21 animals were given chlorpromazine as those of group V and were preconditioned as follows: (C) 1 min ® 5 min ® (C) 1 min ® 5 min ® (C) 30 min ® final reperfusion. Nine animals (32.8%) recovered the sensitive and motor functions and 2(9.52%) experienced partial recovery. The remaining ones (47.68%) became paraplegic. Statistical analysis of the results demonstrated that: 1) there was no significant difference between groups III and IV, and when both of them were compared to group I (p < 0.05); 2) there was no significant difference between groups V and VI, but the difference was significant when both of them were compared to group I (p<0.05). Hystologic study - Twelve animals were assigned exclusively to histologic study: 6 control animals and 6 that were preconditioned as follows: (C) 1 min ® 5 min ® (C) 1 min ® 5 min ® (C) 30 min ® 5 h reperfusion. The percentage of ischemic neuronal cells showed a great dispersion of values, with no significant difference between groups, considering the median of those values (p < 0.005).

Proteção farmacológica da medula espinal isquémica

Ketamine (30 mg/kg, IV) and chlorpromazine (2mg/kg, IV) were evaluated as pharmacological agents, for protection of the ischemic spinal cord in a rat model. A thirty-minute period of ischemia obtained by occlusion of the proximal descending thoracic aorta was followed by reperfusion. In 70 animals (medium weght-380g) distributed in 7 equal groups, the results regarding the complete motor and sensitivity function recovery were as follows: 1) Sham-operation: 100%; 2) Ischemia-reperfusion: 0%; 3) Ketamine, 1 minute before ischemia: 30%; 4) Ketamine, 10 minutes before ischemia: 50%; 5) Chlorpromazine, 1 minute before isquemia: 50%; 6) Chlorpromazine, 1 minute before reperfusion: 10%; 7) Ketamine+chlorpromazine, 1 minute before ischemia: 60%. Both pharmacological agents were effective in the protection of the ischemic spinal cord, as confirmed by the microscopic study. However, comparison of several groups showed statistical significant difference for groups 6 and 7, only. Perfusion of the subarachnoid space revealed excessive amounts of neuro-excitatories amino-acids, L-aspartate and L-glutamate.

Cardioplegia sangüínea normotérmica intermitente anterógrada: estudo experimental em coelhos

Purpose: To study the degree of myocardial protection provided by intermittent infusion of normothermic blood cardioplegia during 60 minutes in normal rabbit hearts. Methods: The study was conducted on 32 New Zeland rabbits. There were 2 stages in this study: Stage I: Metabolic study after ischemia without reperfusion, and Stage II: Metabolic and functional study after reperfusion. The reperfusion was performed with a parabiotic system of perfusion. The glycogen concentration and mitochondrial respiration of the ventricular myocardium immediately after the intermittent infusion period of cardioplegia (Stage I) and after reperfusion (Stage II). During reperfusion the assessment of left ventricular function (dP/dtmax) was realized. Results: There was significant fall in myocardial glycogen levels of 58% in comparison with controls at the end of the intermittent infusion period of cardioplegia (Stage I). Glycogen level differences were not significant after reperfusion (Stage II). The differences in the results of the mitochondrial respiration were not significant in both Stages. The values of dP/dtmax, in Stage II were 903.39 ± 113.46 mmHg/s and 1.043 ± 256.94 mmHg/s, for experimental and control groups respectively. The difference was not significant. Conclusions: The intermittent anterograde normothermic blood cardioplegia infusion every 20 minutes during 60 minutes is an efficient method of myocardial protection in normal rabbit hearts.

Intraoperative Measurement of the Orifice Area in Patients with Mitral Valve Stenosis

This study was carried out in ten patients in order to compare results of mitral valve area evaluated by a new intraoperative technique and those provided by conventional hemodynamic methods. The results obtained correlated very well (r = 0.95) with values calculated by the Gorlin formula. Paired data checking were closer than 0.3 cm2 in all but one of patients with moderately severe mitral stenosis. It is concluded that the method for intraoperative measurement of the mitral valve area is simple, safe and reliable.

Remarkable 23-year survival after bilateral thoracic melanoma metastasectomy

The prognosis of patients with metastatic melanoma is poor, with an annual risk of death of approximately 20% during the first 3 years. The survival average is only 6 to 8 months, and the 5-year survival rate is around 5%. This report describes a remarkable clinical outcome of complete resection of pulmonary metastatic melanoma. The 72-year-old woman is still alive without relapse 27 years after the initial diagnosis and 23 years after the last tumor excision. This remarkable outcome would indicate that the tumor cell population was composed of a particular metastatic phenotype.

Sanguineous normothermic, intermittent cardioplegia, effects on hypertrophic myocardium. Morphometric, metabolic and ultrastructural studies in rabbits hearts

OBJECTIVES The present investigation aimed to study the protective effect of intermittent normothermic cardioplegia in rabbits hypertrophic hearts. METHODS The parameters chosen were 1) the ratio heart weight / body weight, 2) the myocardial glycogen levels, 3) ultrastructural changes of light and electron microscopy, and 4) mitochondrial respiration. RESULTS 1) The experimental model, coarctation of the aorta induced left ventricular hypertrophy; 2) the temporal evolution of the glycogen levels in hypertrophic myocardium demonstrates that there is a significant decrease; 3) It was observed a time-dependent trend of higher oxygen consumption values in the hypertrophic group; 4) there was a significant time-dependent decrease in the respiratory coefficient rate in the hypertrophic group; 5) the stoichiometries values of the ADP: O2 revealed the downward trend of the values of the hypertrophic group; 6) It was possible to observe damaged mitochondria from hypertrophic myocardium emphasizing the large heterogeneity of data. CONCLUSION The acquisition of biochemical data, especially the increase in speed of glycogen breakdown, when anatomical changes are not detected, represents an important result even when considering all the difficulties inherent in the process of translating experimental results into clinical practice. With regard to the adopted methods, it is clear that morphometric methods are less specific. Otherwise, the biochemical data allow detecting alterations of glycogen concentrations and mitochondria respiration before the morphometric alterations should be detected.

Contratura isquêmica do miocárdio: estudo experimental em ratos

Ischemic contracture of the heart (ICH) has been largely employed for the investigation of global heart ischemia physiopathology. We herein describe a simple ICH experimental model. Eight Wistar rats, anesthetized with sulfuric ether, were studied. The heart was rapidly removed by thoracotomy, and then immersed in a 37°C saline bath. A latex balloon catheter placed in the left ventricle and distended to 20 mmHg was used to detect ICH onset (ICHO) and intensity (ICHI). A 5 mmHg baseline elevation pepresented ICHO. ICHI was represented by peak balloon pressure. ICH dP/dT was calculated. The results (mean ± standard deviation) were similar to the literature: ICHO (min) = 15.5 ± 0.59; ICHI (mmHg) = 62.0 ± 5.81; dP/dT (mmHg/min) = 14.2 ± 3.05.

Implante subvalvar do anel da prótese no tratamento cirúrgico dos aneurismas da aorta ascendente

Descreve-se modificacao tecnica da operacao de Bentall e DeBono, para substituicao completa da aorta ascendente e valva aortica. Consiste na passagem de pontos separados em U, sucessivamente, no anel de fixacao da protese e no anel da valva aortica. A posicao subvalvar do anel protetico, assim obtida, facilita o reimplante dos ostios coronarios, sobretudo quando se encontram pouco deslocados, distalmente, como nos pequenos aneurismas. Alem disso, a anastomose proximal tubo-aortica, resulta mais segura. Quinze pacientes portadores de aneurisma da aorta ascendente foram operados por essa tecnica: 14 com proteses separadas e 1 com tubo valvado. Com uma excecao, nos demais foi possivel fazer o reimplante direto dos ostios coronarios na protese tubular. Ocorreram 2 obitos hospitalares nao relacionados a tecnica. Os outros 13 pacientes foram seguidos por periodos variaveis de 72 dias a 109 meses, nao se constatando qualquer disfuncao da protese valvar em avaliacoes clinicas e ecocardiograficas. Destes, 2 faleceram apos 6 e 40 meses, de causa ignorada e disseccao de aneurisma toracoabdominal, respectivamente.

Efeitos da pentoxifilina sobre as plaquetas e hemodinâmica de pacientes com valvopatias adquiridas, operados com circulação extracorpórea

Pentoxifilina (Trental®), vasodilatador com acao reologica, foi administrada a valvopatas adquiridos (7 pacientes - 2 reoperacoes), antes (1.200mg v.o./dia/3 dias) e durante a operacao (1 mg/kg/90 min e.v.) a fim de avaliar seus efeitos sobre as plaquetas e hemodinâmica (grupo pentoxifilina - GP) Oxigenadores de bolhas, hipotermia moderada e cardioplegia sanguinea, fria, intermitente foram usados. Hematocrito, hemoglobina, numero de plaquetas e indice de agregados plaquetarios circulantes, perdas sanguineas, volume de transfusoes e debito cardiaco, entre outras variaveis, foram seguidos ate a 12o hora do p.o.. Os resultados foram comparados com os de um grupo controle (GC) (6 pacientes -1 reoperacao) atraves de testes nao parametricos de Wilcoxon e Mann Whytnei). A pentoxifilina, protegendo as plaquetas, determinou melhores condicoes de coagulacao e menor sangramento p.o. Entretanto, seu efeito vasodilatador foi reduzido ou nulo, sem nenhum beneficio para a circulacao periferica, resistencia vascular sistemica e debito cardiaco.

Anastomose mamária interna-artéria pulmonar para o tratamento paliativo das cardiopatias congênitas cianóticas

The systemic-pulmonary shunts are an important procedure to treat and prepare, for the final correction, cyanotic patients with hypoplastic pulmonary arteries. All of them have advantages and disadvantages, and the results will depend on the age and weight of the patients and the complexity of their heart disease. The present study reports seven internal mammary-pulmonary anastomosis, made through right (2) or left (5) thoracotomies, in patients with Tetralogy of Fallot and hypoplastic pulmonary arteries, from 2 to 63 months of age (m = 18,4) and mean weight of 7.9 kg. There were two deaths (1st and 2nd days), due to thrombosis of the internal mammary, where it was clamped. Two patients went to total correction (1 month and 3 years later). In the first case, the shunt was made due to the general conditions of the child, despite the good size of the pulmonary arteries. In the second case (a 15 months old boy, in whom a classical Blalock-Taussig shunt was made and thrombosed in the 3rd month of life) was possible to follow the progressive enlargement of the pulmonary arteries. In both the shunts were well functioning and the total correction was successful. Three patients are waiting for their best time for final procedures. Despite the small number and the short period of observations, the authors do believe that the internal mammary-pulmonary artery anastomisis is palliative option for these patients. The best results are obtained among the eldest children that are not in an emergency situation and not involving small pulmonary arteries.