RESUMO
BACKGROUND: Endomyocardial fibrosis is a distinct form of heart disease leading to restrictive ventricular filling and cardiac failure. The disease is characterized by a marked thickening of the endocardium due to the deposition of dense fibrous tissue composed of wavy bundles of collagen. Changes in collagen composition and an abnormal increase in its concentration result in a stiffer myocardium and ventricular diastolic dysfunction. The nature of cardiac collagens and the relative proportions of collagen types in endomyocardial fibrosis have not been documented in the literature. METHODS AND RESULTS: This study analyzed collagen composition in the cardiac tissues of 13 patients with endomyocardial fibrosis and 6 individuals who were the victims of traffic accidents or suicidal deaths and did not have any heart disease. We estimated the relative proportions of types I and III collagen after pepsin digestion of the tissue and separation of the emerging peptides by sodium dodecyl sulfate polyacrylamide gel electrophoresis. The mean type I:III collagen ratio was 0.51+/-0.06 in normal individuals, and 0.93+/-0.43 in patients with endomyocardial fibrosis (p<0.05). The alteration in the type I:III collagen ratio was due to a disproportionate increase in type I collagen. CONCLUSIONS: The results indicate that a selective increase in type I collagen may contribute to the impaired diastolic distension of the ventricles in patients with endomyocardial fibrosis.
Assuntos
Adulto , Colágeno Tipo I/metabolismo , Colágeno Tipo III/metabolismo , Eletroforese em Gel de Poliacrilamida , Fibrose Endomiocárdica/metabolismo , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Miocárdio/metabolismoRESUMO
Effect of infusion of stroma free haemoglobin solution into mice and rabbits was studied. Though no abnormalities were noted in mice, pulmonary vasospasm and hepatocytic necrosis were seen in all rabbits. In addition to reports that low adenosine deaminase levels in the solution could be a cause of vasoconstriction, it is proposed on the basis of present results that either denaturation of haemoglobin molecule itself or release of super oxide anion during oxygenation of haemoglobin, could cause cellular damage leading to toxicity.