A novel method for freezing and storing research tissue bank specimens.

Preserving small pieces of frozen tissue for possible future ancillary studies ("tumor banking") usually involves either placing a small piece of tissue in a cryovial and snap freezing it in liquid nitrogen or embedding and freezing the tissue in a block of cryopreservation medium, such as optimal cutting temperature (OCT) compound. The cryovial storage method leaves an irregularly shaped piece of tissue frozen to the side of the plastic vial, where it is exposed to air, subject to desiccation ("freezer burn"), and difficult to remove, but the vials are easy to store. The OCT method results in good morphological preservation, but yields a large awkwardly stored block from which it may be difficult to locate and recover small specimens. We have proposed a novel method of storing tissue bank specimens, the "capsule-freeze" method, which combines the advantages of OCT specimen preservation with those of cryovial specimen storage. Using this method, a tissue specimen is "snap-frozen" in OCT within a size "00" VCap pharmaceutical capsule, then the capsule is stored within a 1.5-mL cryovial. The specimen is harvested by simply cutting a slice out of the capsule and sealing the cut ends with OCT before their return to the freezer. The slice is then embedded en face within an OCT block before frozen sectioning. Morphological preservation is excellent, and the capsules are very easy to store. Occasional cracking that we found with the use of gelatin capsules is greatly diminished with the use of VCaps cellulose-walled capsules. The OCT can be easily removed by rinsing in cold 70% ethanol solutions. This method of tissue storage is ideal for the small specimens that are now commonly archived in these days of tissue sparing surgery.

Morbidity in immunosuppressed (SCID/NOD) mice treated with reovirus (dearing 3) as an anti-cancer biotherapeutic.

Specific viral oncolysis of cancer cells has aroused great interest as a potential anti-cancer therapy. Reovirus was proposed as an anti-cancer biotherapeutic several years ago, as it elicits virus-mediated death of human cancer cells both in vitro and in mouse model systems. A common model system for reovirus oncolysis is the NOD/ LtSz-scid/scid (SCID/NOD) immunocomprimised mouse. While human tumour xenografts are effectively killed by intra-tumour injections of reovirus, the mice often exhibit discoloration and necrosis of extremities including feet, distal leg, tail and ears several weeks after injection. This phenomenon never occurs in sham-injected mice, nor is it observed in wild type or nude mice. The pathogenesis of this "Black Foot" lesion has not yet been described, but may be of relevance for future human studies of biotherapeutics. Examination of SCID/NOD mice was performed at various time points following intratumoral injection of reovirus. Immunohistological evaluation of tissues reveals infection of cardiac myocytes and venous endothelial cells at approximately 2 days post infection. Over time, venules and veins showed a mixed inflammatory vasculitis and thrombus formation. Synchronously, the heart showed diffuse myocyte death, with dystrophic calcification. The results indicate that the "Black Foot" syndrome is likely due to venous vasculitis secondary to reovirus infection, on a background of reovirus myocarditis and heart failure. The rationale for the selective susceptibility of venous over arterial endothelium to reovirus infection is currently unknown. The results of this study may be relevant to the use of oncolytic viruses, particularly reovirus, in the anti-cancer therapy of immunosuppressed patients.