Reports indicate that cryopreserved aortic valve allografts have a better long-term survivability than other bioprostheses, such as the porcine xenograft. Unlike xenografts, allograft valves do not require treatment with glutaraldehyde and may therefore retain much of their original mechanical function. (American Assoc. for Thoracic Surgerry)

Persistent expression of human genes by the xenografts at higher passages was assessed by RT-PCR amplification of the human β–globin gene. This xenograft model was used in the preclinical evaluation of an adenoviral vector containing a β-galactosidase reporter gene and a wild-type p53 gene. (ScienceDirect)

A transparent window chamber allowed noninvasive microscopic observation of human tumor xenograft tissue in athymic nude mice. The xenografts were derived from the LS174T colon carcinoma cell line shown to express CEA in vitro (18) and in vivo (19–21). (The National Academy of Sciences)