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[Causes of rupture of formalinized xenovalves in the post-transplantation period].

The article discusses results of the morphological study of xenografts of the pig's valves fixed in 0.32% and 4% solution of formaldehyde which remained in the human heart during the period ranging from 21 months to several hours. In the xenovalves there occurred progressive destructive changes in their connective-tissue basis, which led to weakening of the mechanical strength and to rupture of the cusps. In the majority of cases, no morphological signs of immune or nonspecific inflammatory cellular reaction were observed. The authors hold that polycondensation of protein molecules occurring in the course of preservation under the effect of formaldehyde, and formation of "superstrong" structures at the expense of increased number of transversal connections between collagenous fibres not always could ensure sufficient mechanical strength of the cusps of the graft.