Pseudotumor of the heart: subepicardial hematoma of the right atrium

A 28-year-old man with a huge subepicardial hematoma of the right atrium, which is so rare that a review of the literature has failed to disclose similar case, is reported. Suspecting of rhabdomyoma, we excised free wall of the right atrium and a part of lateral wall of the superior vena cava. The excised part was reconstructed with expanded polytetrafluoroethylene (Gore tex). This synthetic material has a few merit and application of this one to the reconstruction in the venous system seems more promising. He was discharged with a regular sinus rhythm, normal heart size three months after the operation. The histologic examination of the excised material revealed amorphous blood clots and chronic granulation tissue containing hemosiderin-cells. The cause of the hematoma was not clarified even by microscopic examination.

Studies on copolymers of collagen and a synthetic polymer. First report--experimental study on biocompatibility of laminar copolymers of collagen and a synthetic polymer

To develop biomaterials for semiparmanent substitution, we are studying copolymers of collagen and a synthetic polymer. In this study, in order to test tissue compatibility, the laminar copolymers were prepared from bovine collagen treated with proctase to remove telopeptides and synthetic polymers such as polyethylene, polyvinylalcohol, silicon gum etc., by the OKAMURA-HINO metthod, namely polymerization achieved by the introduction of cross-lincages, applying plasma discharge and gamma-irradiation. These copolymers were implanted into dorsal subcutaneous tissue in rabbits and removed after 1, 2, 3, 4 and 6 weeks to be examined by light microscope and electron microscope. One or two weeks after implantation, we observed that a large number of fibroblasts gathered on the surface of the grafted collagen. After 3 or 4 weeks, bridges of collagen fibrils were observed between the copolymers and rabbit tissue. These copolymers were firmly adhered to the tissues and separable only with difficulty. These results showed that the copolymers maintain the capacity for extreme strong bonding for at least 6 weeks and possess high tissue compatibility. From that we concluded copolymers are useful as a biomedical material.