- Email: [email protected]
Preservation of pancreatic islets
570
ABSTRACTS, 24th ANNUAL
about a pronounced freezing tolerance development which is coincident with marked changes in phospholipid and polyunsaturated fatty acid catabolism and promoted ethylene formation (a new reaction phase?). It is also associated with a sudden water potential decrease in a tissue. The subfrozen leaf tissue shows a higher capacity for a cell expansion than the nonsubfrozen one if allowed to reabsorb water from the medium (at low, positive temperature). It still maintains water potential at the level lower than that in the nonsubfrozen specimens. That phenomenon may have an important meaning for the avoidance of intracellular ice formation upon further temperature decreases. (See Fig. 73(l)). SYMPOSIUM VI-PROGRESS IN CELL, TISSUE, AND ORGAN PRESERVATION: BASIC AND APPLIED ASPECTS. PART I 74. Undercooling: Uncoupling Low Temperature from Freezing. S. E MATHIAS (Pafra Ltd Bio-
preservation Division, 150 Science Park, Cambridge, United Kingdom). Undercooling of aqueous droplets has been used for decades as a technique for the study of ice nucleation per se, and several workers have noted that cells can be substantially undercooled for brief periods in the absence of extracellular ice. Undercooling is commonly used in the insect and plant world as a strategy for avoiding lethal intracellular freezing on exposure to subzero temperatures. In the laboratory, the ability of a wide variety of cells to undercool substantially has been demonstrated using differential scanning calorimetry. All the cell types we have tested, from plant, animal or microorganism origins can be undercooled slowly to - 25°C or below before the onset of intracellular freezing. Storage of cells at low temperatures without freezing is an attractive proposition for several reasons, for example, no osmotic stress is im-
FIG. 1. (Abstract 73) Scheme of metabolic events observed in a leaf tissue of winter rape (Brassica napus L., var oleifera) plants. Broken line: killing point temperature. AEC and ARC: adenylate energy charge and anabolic reduction charge, respectively.
MEETING
posed on the cell during cooling, and no cryoprotectant is needed to alleviate the stress of freezing. Further, alternative storage methods for noncellular biological materials (enzymes, hormones) are very much in demand where conventional freeze drying or freezing methods fail or are too damaging. The development of the emulsion droplet technique where cells or biochemical preparations are dispersed throughout a viscous inert oil phase which solidifies on cooling forms the basis of the method for undercooled storage. The aqueous droplets are sufficiently small to undercool successfully, and are fixed and isolated from each other so that in the event of any chance nucleation, ice cannot propagate through the sample. Successful preservation of cell types including red blood cells and microorganisms is now a practical possibility and storage of enzyme solutions susceptible to freeze drying/freezing is particularly successful. No loss of activity is seen in dilute solutions stored undercooled at -20°C for more than 1 year. The possibility of holding cells, proteins, hormones, etc. in the undercooled state has enabled us to study protein stability and denaturation at low temperature without the effects of ice formation and solute concentration. Undercooling is an alternative strategy for low temperature preservation of biological materials and is an experimental technique for the study of biological processes at subzero temperatures. of Pancreatic Islets. RAYMOND V. RAJO~TE(Department of Medicine, University of Alberta, Edmonton, Alberta, Canada). 76. Clinical Methods of Organ Preservation. JAMES H. SOUTHARD(Department of Surgery University of Wisconsin, Madison, Wisconsin). SESSION VI-PROGRESS IN CELL, TISSUE, AND ORGAN PRESERVATION: BASIC AND APPLIED ASPECTS. PART I 75. Preservation
77. Viability
of Supercooled Donor Hearts for plantation. S. SUMIDA, K. EBINE,*
Trans-
S. TAMURA,* M. LEE,* AND K. SATO* (Division of Cardiovascular Surgery, National Fukuoka Central Hospital, Jonai 2-2, Chuoku, Fukuoka, 810 Japan; and *Division of Cardiovascular Surgery, Toho University Ohashi Hospital, Meguro, Tokyo, Japan). With the increasing use of heart transplantation as a therapeutic regimen, the demand becomes greater for suitable methods of interim storage and the preoperative nondestructive evaluation of donor heart viability. In this study, a new experimental model to evaluate the viability of the donor heart, using a )iP-NMR spectroscopy was introduced in isolated perfused rabbit heart. And, the effects of simple hypothermia and supercooling on the ischemic derangement of myocardial energy metabolism of donor hearts suggesting viability were studied. Rabbits (NZW, 1.5-2 kg) were
ABSTRACTS, 24th ANNUAL
about a pronounced freezing tolerance development which is coincident with marked changes in phospholipid and polyunsaturated fatty acid catabolism and promoted ethylene formation (a new reaction phase?). It is also associated with a sudden water potential decrease in a tissue. The subfrozen leaf tissue shows a higher capacity for a cell expansion than the nonsubfrozen one if allowed to reabsorb water from the medium (at low, positive temperature). It still maintains water potential at the level lower than that in the nonsubfrozen specimens. That phenomenon may have an important meaning for the avoidance of intracellular ice formation upon further temperature decreases. (See Fig. 73(l)). SYMPOSIUM VI-PROGRESS IN CELL, TISSUE, AND ORGAN PRESERVATION: BASIC AND APPLIED ASPECTS. PART I 74. Undercooling: Uncoupling Low Temperature from Freezing. S. E MATHIAS (Pafra Ltd Bio-
preservation Division, 150 Science Park, Cambridge, United Kingdom). Undercooling of aqueous droplets has been used for decades as a technique for the study of ice nucleation per se, and several workers have noted that cells can be substantially undercooled for brief periods in the absence of extracellular ice. Undercooling is commonly used in the insect and plant world as a strategy for avoiding lethal intracellular freezing on exposure to subzero temperatures. In the laboratory, the ability of a wide variety of cells to undercool substantially has been demonstrated using differential scanning calorimetry. All the cell types we have tested, from plant, animal or microorganism origins can be undercooled slowly to - 25°C or below before the onset of intracellular freezing. Storage of cells at low temperatures without freezing is an attractive proposition for several reasons, for example, no osmotic stress is im-
FIG. 1. (Abstract 73) Scheme of metabolic events observed in a leaf tissue of winter rape (Brassica napus L., var oleifera) plants. Broken line: killing point temperature. AEC and ARC: adenylate energy charge and anabolic reduction charge, respectively.
MEETING
posed on the cell during cooling, and no cryoprotectant is needed to alleviate the stress of freezing. Further, alternative storage methods for noncellular biological materials (enzymes, hormones) are very much in demand where conventional freeze drying or freezing methods fail or are too damaging. The development of the emulsion droplet technique where cells or biochemical preparations are dispersed throughout a viscous inert oil phase which solidifies on cooling forms the basis of the method for undercooled storage. The aqueous droplets are sufficiently small to undercool successfully, and are fixed and isolated from each other so that in the event of any chance nucleation, ice cannot propagate through the sample. Successful preservation of cell types including red blood cells and microorganisms is now a practical possibility and storage of enzyme solutions susceptible to freeze drying/freezing is particularly successful. No loss of activity is seen in dilute solutions stored undercooled at -20°C for more than 1 year. The possibility of holding cells, proteins, hormones, etc. in the undercooled state has enabled us to study protein stability and denaturation at low temperature without the effects of ice formation and solute concentration. Undercooling is an alternative strategy for low temperature preservation of biological materials and is an experimental technique for the study of biological processes at subzero temperatures. of Pancreatic Islets. RAYMOND V. RAJO~TE(Department of Medicine, University of Alberta, Edmonton, Alberta, Canada). 76. Clinical Methods of Organ Preservation. JAMES H. SOUTHARD(Department of Surgery University of Wisconsin, Madison, Wisconsin). SESSION VI-PROGRESS IN CELL, TISSUE, AND ORGAN PRESERVATION: BASIC AND APPLIED ASPECTS. PART I 75. Preservation
77. Viability
of Supercooled Donor Hearts for plantation. S. SUMIDA, K. EBINE,*
Trans-
S. TAMURA,* M. LEE,* AND K. SATO* (Division of Cardiovascular Surgery, National Fukuoka Central Hospital, Jonai 2-2, Chuoku, Fukuoka, 810 Japan; and *Division of Cardiovascular Surgery, Toho University Ohashi Hospital, Meguro, Tokyo, Japan). With the increasing use of heart transplantation as a therapeutic regimen, the demand becomes greater for suitable methods of interim storage and the preoperative nondestructive evaluation of donor heart viability. In this study, a new experimental model to evaluate the viability of the donor heart, using a )iP-NMR spectroscopy was introduced in isolated perfused rabbit heart. And, the effects of simple hypothermia and supercooling on the ischemic derangement of myocardial energy metabolism of donor hearts suggesting viability were studied. Rabbits (NZW, 1.5-2 kg) were