Flounder antifreeze peptides increase the efficacy of cryosurgery

Type I antifreeze protein (AFP) from the winter flounder (Pseudopleuronecte s americanus) was used as an adjuvant to cryosurgery of subcutaneous tumors of Dunning AT-1 rat prostate cells grown in Copenhagen rats. The cryosurgi cal procedure was performed with a commercially available cryosurgery devic e (CRYO-HIT. Galil Medical) with clinically relevant single- and double-fre eze protocols. Injury was assessed with the alamar blue indicator of metabo lic activity. The assay gave anomolous results when used to assess the exte nt of injury immediately following the procedure, underestimating the exten t of injury. However, a double-freeze procedure with antifreeze protein pre sent was found to give significantly better ablation than a double-freeze w ithout AFP or a single-freeze with or without AFP. (C) 2001 Academic Press.