Cytoprotection by melatonin and growth hormone in early rat myocardial infarction as revealed by Feulgen DNA staining.

Objective: To examine the cytoprotective effect of melatonin or recombinant human growth hormone (hGH) on the early phase of a running myocardial infarction in rats by using the Feulgen staining.

Methods: Rats were subjected to surgical ligature of the left coronary artery or its sham-operation and were studied 1.5 3 h later.

Reduced injury and scar in acute myocardial infarctions treated with human growth hormone.

Repair processes of cells submitted to an injury may exhibit an indirect identifying feature of its activity, based on the amount of connective tissue that could be traced with special stains and morphometry. Hydroxyproline concentration in tissue is also an index with which the presence and amount of repair mechanisms can be assessed. They may be quantitated appropriately in correlation with the end products of collagen, which represent the amount of cicatricial tissue.

[The reduction of the extension and severity of experimental myocardial infarct in pigs with growth hormone. The preservation of the microcirculation].

Administration of hGH during the acute phase of experimental myocardial infarctions in pigs showed several aspects which clearly distinguished the treated group from the control one. In the first case the necrotic segment appeared considerably smaller than in the control group but also exhibit a qualitative different necrotic pattern in the histologic aspect, i.e.

Preservation of the myocardial collagen framework by human growth hormone in experimental infarctions and reduction in the incidence of ventricular aneurysms.

We administered human growth hormone to a group of rats with experimental myocardial infarctions, in order to observe its action on the connective tissue repair process and the consequent effect on postinfarction ventricular aneurysms. Myocardial connective tissue displays a complex layout around each myocyte and among neighboring ones. It has been shown to be highly vulnerable to acute coronary ischemia which affects its diverse components in accordance with a precise timetable.

Bivalent effects of human growth hormone in experimental myocardial infarcts. Protective when administered alone and aggravating when combined with beta blockers.

Human growth hormone (hGH) administered alone revealed itself as a useful drug to prevent ventricular aneurysm formation in experimental myocardial infarctions in rats and is also able to diminish and change the usually expected pattern of wall necrosis. A protective action on the collagen framework of myocytes has been confirmed as one of the main causes responsible for the above mentioned findings. There are other positive metabolic actions on the myocardial cell although not completely known yet.

Ventricular aneurysms: a geometrical-dynamical model.

A geometrical-dynamical model has been designed with the aim to reproduce the early phases of ventricular aneurysms formation. Possible deleterious forces within a solidary-dynamic structure start when a partial or localized loss of contractility arises. A following important aspect is related to the compressive effects of those altered cells over the normally contracting neighborhood.

[Histologic correlation of ischemic and chagasic ventricular aneurysms. Relation to physiopathology].

We depict the histologic findings of ventricular aneurysms in 8 patients, 5 with Chagas heart disease and 3 secondary to myocardial infarction. Chagas disease and ischemic cardiopathy are the 2 conditions which show the highest incidence of ventricular aneurysms. The first one averages more than 60% in large series.

Ventricular aneurysms in chronic Chagas' cardiopathy.

Ventricular aneurysms in Chagas' disease is the most frequent pathologic finding of this condition. It is possible to diagnose this lesion during early stages by means of cineventriculography, or echocardiography in B mode. An early diagnosis is mandatory for those cases in which the most important clinical manifestation is the presence of frequent ventricular arrhythmias which are often refractory to many forms of treatments.