The effect of liquid nitrogen submersion on cryopreserved human heart valves.

Author(s): Adam M, Hu JF, Lange P, Wolfinbarger L Jr

Publication: Cryobiology, 1990, Vol. 27, Page 605-14

PubMed ID: 2286097 PubMed Review Paper? No

Purpose of Paper

Conclusion of Paper

Studies

1. Study Purpose

   The purpose of this study was to assess and compare the morphological integrity of heart valves cryopreserved in liquid nitrogen vapor with those that were briefly immersed in liquid nitrogen. Heart valve specimens, collected during autopsy, were frozen at a controlled rate in media containing dimethyl sulfoxide (DMSO) then stored in liquid nitrogen vapor at -150 degrees C. A subset of seven specimens were removed from storage in liquid nitrogen vapor, submerged in liquid nitrogen for 5 minutes, and then returned to liquid nitrogen vapor. Specimens analyzed by scanning electron microscopy (SEM) were rapidly thawed and fixed in a solution containing 2.5% glutaraldehyde and 2% formaldehyde.

   Summary of Findings:

   Heart valves that had been immersed in liquid nitrogen displayed normal histology when examined by light microscopy, but clear fractures in the surface and underlying collagen matrix were visible over both the ventricular and aortic surface at a low SEM magnification (57.5x). Examination of specimens immersed in liquid nitrogen at a higher magnification (512x) revealed smaller but more numerous fractures. Microfractures were not observed among specimens that remained in liquid nitrogen vapor.

   Biospecimens

   • Tissue - Heart

   Preservative Types

   • Frozen

   Diagnoses:

   • Autopsy
   • Not specified

   Platform:

   Analyte	Technology Platform
   Morphology	H-and-E microscopy
   Morphology	Electron microscopy

   Pre-analytical Factors:

   Classification	Pre-analytical Factor	Value(s)
   Biospecimen Preservation	Cooling or freezing method/ rate	Liquid nitrogen Liquid nitrogen vapor

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