Contractility changes of the right and left ventricular muscle after chronic myocardial infarction

Contractility changes and adaptive responses resulting from acute left ventricular (LV) myocardial infarction are not restricted to the LV myocardium. The reduced LV function increases the right ventricular (RV) pressure load and neurohumoral factors, activated by the infarction episode, might have pan-cardiac effects. In the present study we investigated the mechanical activity of RV and LV isolated papillary muscles from 30-day infarcted male Wistar, 3-4-months old rat hearts. LV myocardial infarction was produced by ligature of the descending anterior branches of the left coronary artery (INF group). Control animals were submitted to sham surgery (SO group). Both groups were studied 30 days after the infarction procedure. Post-infarction hypertrophy was evaluated by measuring the cell diameters in the nuclear region. Contractility changes were analyzed by determining the isometric force (F) and the rate of force development (dF/dt) of papillary muscles from LV and RV. The effects of variations in extracellular Ca2+ concentrations (0.6, 1.25, 2.5 and 3.75 mM)were determined on twitches and tetanic contractures obtained during caffeine perfusion (2.5 mM) and were used to assess changes at the contractile protein level. The activity of the sarcoplasmic reticulum was evaluated by using the post-rest potentiation phenomenon. Hypertrophy occurred in both ventricles after infarction, with the RV chamber showing a pressure overload pattern while LV myocytes developed a volume overload pattern. F and dF/dt of LV papillary muscles decreased after infarction but did not change in the RV preparations. Positive inotropic changes obtained with increasing Ca2+ concentrations and the development of tetanic tension were reduced after infarction only in LV papillary muscles. The relative potentiation of post-rest contractions was only affected in the LV myocardium showing a decrease after infarction. These results suggest that different adaptive changes occur in the LV and RV myocardium after infarction. While the RV myocardium maintains its contractility the LV myocardium displays a depressed mechanical activity problably due to changes at the contractile mechinery level and to alterations in the Ca2+ handling process.

Introduçäo à informática nas áreas de saúde e biológicas na UFPE / Introduction to informatic in health and biological areas in UFPE

Neste trabalho é apresentado o desenvolvimento de um programa de ensino e pesquisa para consolidação de um grupo em bioinformática na Universidade Federal de Pernambuco. O grupo vem desenvolvendo projetos e organizando cursos de informática aplicada às ciências da saúde e biológicas para alunos de graduação e pós-graduação, bem como para professores visando à inserção da informática no programa de suas disciplinas.

Edubiosoft: um software auxiliar no ensino de bioquímica / Edubiosoft: auxiliary software in biochemistry lectures

Com a finalidade de aprimorar o ensino de buioquímica, através de novas técnicas de lecionamento, foi desenvolvido nos Setores de Biotecnologia e de Bioinformática do LIKA, o programa EDUBIOSOFT, que através da utilização integrada de textos e imagens fornece ao aluno uma ferramenta de apoio ao aprendizado e avaliação do conhecimento de temas da bioquímica.

Dermasoft: um sistema de instruçäo assistido por computador (CAI) para o ensino de dermatologia / Dermasoft: computer assisted instruction system (CAI) for dermatology lectures

Com o intuito de desenvolvimento novas técnicas de divulgação e ensino em dermatologia, os Setores de Biotecnologia e de Bioinformática do Laboratório de Imunopatologia Keizo Asami (LIKA) juntamente com o Departamento de Dermatologia da Universidade federal de Pernambuco (UFPE), está desenvolvendo através da tecnologia Computer Assisted Instuction (CAI), o DERMASOFT. Este software consiste na utilização integrada de bases de textos, imagens e casos clínicos no ambiente Windows com o objetivo de ser um instrumento de apoio ao ensino e de atualização para dermatologia e profissionais interessados na área.

Propanolol reduces myocardial hypertrophy in the right cardiac chambers after infarction in rats

The effects of chronic propanolol (Prop) therapy on the post infarction myocardial hypertrophy of infarction rats were studied by histological techniques. male albino rats were submitted to left coronary artery ligation to produce infarction or to sham surgery (Con, N=6)., Infarction rats (Inf) were divided into 2 groups receiving Prop (2.5 mg/kg, twice a day, N+6) or saline (N=6) for one month, respectively. Myocyte diameters were measured in longitudinally oriented sections in the four heart chambers (60 cells/chamber). inf produced a significant increase in mean diameter of myocytes from the right atrium and ventricle and from the left atrium. In the right ventricle, myocyte diameter increased from 8.9 ñ 0.5 um in the Con group to 12.5 ñ 0.6 um in the the Inf group (P<0.05). Under Prop, myocyte diameter was reduced (P<0.05) to 9.8 ñ 0.9 um. Similar values were observed in the right atrium. In the left atrium, Prop produced only a partial reversion of the postinfarction hypertrophy. In the left ventricle, myocyte diameter was not significantly changed after Inf or Prop therapy. These data show that beta blockers reduce the myocardial hypertrophy in the right heart chambers after experimental infarcts in rats. This effect can be secondary to reduction of pulmonary hypertension or to blockade of direct effects of catecholamines on myocardial fibers or both