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Current and projected restraints on the use of animals in research
566
ABSTRACTS,
26th ANNUAL
tissue is a volume of pure water that freezes from the outer surface. Several mathematical methods of solution have been developed by the author and will be described. They include perturbation methods and front tracking finite element methods. A more complex model assumes that the tissue can be represented as a solution of saline. Freezing of saline is characterized by the rejection of solute abead of the ice front. Experimental results illustrating this process will be shown together with the description of a front tracking finite element mathematical model. The model describes the process of mass transfer as well as heat transfer during solidification in solutions. Recent experimental studies have shown that biological tissue does not freeze as a homogeneous solution. The water in the blood vessels and in the extracellular space freezes differently from the water in the intracellular space. Experimental results will be shown to illustrate the process of freezing in tissue and a new mathematical model will be presented for the observed process. The model describes the phase transformation process together with the experimentally observed process of water transport between the intracellular and the extracellular space. 91. Food Freezing and and Differences.
Organ
Freezing:
Similarities
D. S. REID (Department of Food Science & Technology, University of California, Davis, California).
Bulk freezing is necessary in the preservation of food and also in the preservation of organs. The primary objectives of food freezing are to retain “eating quality” and nutritional value. There is no a priori need to retain tissue viability. Indeed, tissue may already be dead prior to freezing. The primary objective of organ freezing is the maintenance of viability and function. Because of the differing objectives, the methods employed can differ. It is instructive to consider physical descriptions of the methods of both food freezing and organ freezing to ascertain from these descriptions similarities and differences in the physical processes. In food freezing, procedures termed fast and slow freezing may be used. Often the heat exchange medium is around -50°C. Additives, infrequently, may be used, as these additives must be safely edible and also palatable. Heat exchange calculations exist which can approximately describe the time course of freezing. The closeness of the approximation depends upon the conditions of freezing. Cryogenic freezing is sometimes employed. Storage temperatures are around -30°C or above. In organ freezing, cryogenic cooling may be more common. Additives are often used, provided that they can be perfused into the organ. The major limitation to their use is that they must have no irreversible toxic consequence. Calculations of freezing behavior must take into account the conditions for survival of cells at all
MEETING
locations, as cell survival is necessary for successful organ preservation. PLENARY
SESSION
92. Current and Projected Animals in Research.
Restraints
II on the
Use
of
M. MICHAEL SWINDLE (Medical University of South Carolina, Charleston, South Carolina).
The use of animals in research has become a highly emotional subject within the public. At present 1215% of the public oppose the use of animals in research, while 6040% favor their continued usage depending upon the species of animal in question. These percentages are approximately the same as those from a survey taken before World War I. Because of ready access to the news media and the availability of computerized mailing, this small group has been able to influence various legislative bodies to pass restrictive legislation which either serves to restrict certain species or procedures or increases the cost of research. The scientific community has failed until recent years to mount a response to the propaganda campaign mounted by antivivisectionists. This apathy on the part of the scientific community combined with arrogant disregard of existing rules and regulations by some institutions has led to an erosion of credibility of the biological sciences. Studies indicate that there will be a continued need for the use of animals in research in the foreseeable future and that current in vitro alternatives are most applicable to toxicology screening. Legislation will continue to become more restrictive unless the scientific community becomes involved in the debate in public and legislative formats. WORKSHOP
V-VITRIFICATION
93. Recent Insights on the Role of Ctyoprotective Agents in Vitrification. DOUGLAS R. MACFAR-
LANE AND M. FORSYTH (Department of Chemistry, Monash University, Clayton 3168, Australia) . Recent efforts worldwide to produce cryoprotective solutions which cause either complete, or almost complete, vitrification of the cell or tissue material have invariably used increasingly complex cocktails of solutes. The reasons why some of these solutes are so much more effective in suppressing ice formation than other related solutes has never been clear. To begin to compare and contrast the role of the solute in aiding vitrification we have examined the nature of the hydrogen bonding interactions between the solute and water and between the solute molecules themselves, via proton nuclear magnetic resonance experiments. These experiments, carried out on neat samples of the solutions, show marked differences between solutes such as ethylene glycol, propane-l,Zdiol, propane-
ABSTRACTS,
26th ANNUAL
tissue is a volume of pure water that freezes from the outer surface. Several mathematical methods of solution have been developed by the author and will be described. They include perturbation methods and front tracking finite element methods. A more complex model assumes that the tissue can be represented as a solution of saline. Freezing of saline is characterized by the rejection of solute abead of the ice front. Experimental results illustrating this process will be shown together with the description of a front tracking finite element mathematical model. The model describes the process of mass transfer as well as heat transfer during solidification in solutions. Recent experimental studies have shown that biological tissue does not freeze as a homogeneous solution. The water in the blood vessels and in the extracellular space freezes differently from the water in the intracellular space. Experimental results will be shown to illustrate the process of freezing in tissue and a new mathematical model will be presented for the observed process. The model describes the phase transformation process together with the experimentally observed process of water transport between the intracellular and the extracellular space. 91. Food Freezing and and Differences.
Organ
Freezing:
Similarities
D. S. REID (Department of Food Science & Technology, University of California, Davis, California).
Bulk freezing is necessary in the preservation of food and also in the preservation of organs. The primary objectives of food freezing are to retain “eating quality” and nutritional value. There is no a priori need to retain tissue viability. Indeed, tissue may already be dead prior to freezing. The primary objective of organ freezing is the maintenance of viability and function. Because of the differing objectives, the methods employed can differ. It is instructive to consider physical descriptions of the methods of both food freezing and organ freezing to ascertain from these descriptions similarities and differences in the physical processes. In food freezing, procedures termed fast and slow freezing may be used. Often the heat exchange medium is around -50°C. Additives, infrequently, may be used, as these additives must be safely edible and also palatable. Heat exchange calculations exist which can approximately describe the time course of freezing. The closeness of the approximation depends upon the conditions of freezing. Cryogenic freezing is sometimes employed. Storage temperatures are around -30°C or above. In organ freezing, cryogenic cooling may be more common. Additives are often used, provided that they can be perfused into the organ. The major limitation to their use is that they must have no irreversible toxic consequence. Calculations of freezing behavior must take into account the conditions for survival of cells at all
MEETING
locations, as cell survival is necessary for successful organ preservation. PLENARY
SESSION
92. Current and Projected Animals in Research.
Restraints
II on the
Use
of
M. MICHAEL SWINDLE (Medical University of South Carolina, Charleston, South Carolina).
The use of animals in research has become a highly emotional subject within the public. At present 1215% of the public oppose the use of animals in research, while 6040% favor their continued usage depending upon the species of animal in question. These percentages are approximately the same as those from a survey taken before World War I. Because of ready access to the news media and the availability of computerized mailing, this small group has been able to influence various legislative bodies to pass restrictive legislation which either serves to restrict certain species or procedures or increases the cost of research. The scientific community has failed until recent years to mount a response to the propaganda campaign mounted by antivivisectionists. This apathy on the part of the scientific community combined with arrogant disregard of existing rules and regulations by some institutions has led to an erosion of credibility of the biological sciences. Studies indicate that there will be a continued need for the use of animals in research in the foreseeable future and that current in vitro alternatives are most applicable to toxicology screening. Legislation will continue to become more restrictive unless the scientific community becomes involved in the debate in public and legislative formats. WORKSHOP
V-VITRIFICATION
93. Recent Insights on the Role of Ctyoprotective Agents in Vitrification. DOUGLAS R. MACFAR-
LANE AND M. FORSYTH (Department of Chemistry, Monash University, Clayton 3168, Australia) . Recent efforts worldwide to produce cryoprotective solutions which cause either complete, or almost complete, vitrification of the cell or tissue material have invariably used increasingly complex cocktails of solutes. The reasons why some of these solutes are so much more effective in suppressing ice formation than other related solutes has never been clear. To begin to compare and contrast the role of the solute in aiding vitrification we have examined the nature of the hydrogen bonding interactions between the solute and water and between the solute molecules themselves, via proton nuclear magnetic resonance experiments. These experiments, carried out on neat samples of the solutions, show marked differences between solutes such as ethylene glycol, propane-l,Zdiol, propane-