Mechanisms underlying degeneration of cryopreserved vascular homografts.

Objective: To analyze the mechanism(s) underlying homograft degeneration, we designed an experimental model in which the behavior of cryopreserved autografts and homografts, as well as fresh autografts, implanted in the same animal was compared.

Methods: A cryopreserved homograft was implanted in the aorta of 14 sheep. The excised aortic autologous segment was then subjected to cryopreservation, and 1 to 8 weeks later it was implanted 1 to 2 cm below the cryopreserved homograft.

The allograft valve in heart transplantation and valve replacement. Genetic assessment of the origin of the cells by means of deoxyribonucleic acid profiles.

Assessment of the cellular origin of allograft valves is essential in comprehending their biologic behavior and in improving preparation methods. In this study we retrospectively analyzed 10 allografts obtained from patients who underwent valve replacement or heart transplantation. Histologic evaluation and deoxyribonucleic acid amplification by polymerase chain reaction technology with fluorescence labeled primers was performed on different parts of the valve leaflets.

Implanted solid human tumours grow under the renal capsule of cyclosporin-immunosuppressed rats.

Cyclosporin (CsA) is a potent immunosuppressive drug widely used in organ transplantation. We transplanted fresh surgical samples from human solid malignant tumours into 45 CsA-immunosuppressed rats. Eight out of nine tumour types grew and remained viable for 5 weeks or more in at least two of the transplanted rats.

The alternative binding site for protein A in the Fab fragment of immunoglobulins.

Twenty-six new human or murine monoclonal immunoglobulins (IgM, IgA, murine IgG1 or human IgG3) with a known V-region sequence were tested for alternative (non-Fc) binding to Staphylococcal protein A. Seven of them did not bind at all. Four immunoglobulins (all mouse IgG1) were bound but easily eluted (at pH 6).

Fine-specificity of the immune response to oxazolones. IV. Furyloxazolone-specific cytolytic T lymphocytes (unlike antibodies) are not heteroclitic.

Antibodies, raised in CBA and C3H mice, to a hapten 2-furyloxazolone (furyl Ox) have a strange (heteroclitic) fine-specificity, having a higher affinity for the chemical analogue 2-styryloxazolone (styryl Ox) than for furyl Ox. Other mouse strains were found to produce 'normal' anti-furyl Ox antibodies, and the heteroclicity was inherited as an Igh allotype-linked trait (Mäkelä, Matoso-Ferreira & Kaartinen 1983). Hapten-specific cytolytic T lymphocytes (CTL) were generated by painting cyclophosphamide-treated mice with chemically reactive haptens, furyl Ox and styryl Ox, and their fine-specificity was investigated.