| Cryostasis and cryonics |
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Chances and weaknesses of a new ideaProf. Dr. Klaus Sames Abstract:
Cryonics tries to preserve humans for the future.Cryonics undertakes the experiment to preserve the human body stopping the biological clock by application of low temperature. This opens the window to future progress for man, in so far that respective methods will be found, which allow reanimation to the living state. Facing this (even if very small) chance cryopreservation (cryostasis) seems to already make sense today. Application of the most advanced scientific insights and own scientific research may increase the chances of reanimation. Efforts of scientists inclined to cryonics today already present an essential contribution to research in cryobiology as a scientific field. Cryonics provides not only a totally new innovative chance opening slowly due to the latest scientific developments, but also an amazingly suggesting idea itself. This holds true especially with respect to the latest progress in cryobiology and the essential role of cryobiological methods for future advances in medicine. Our body is known to depend on continuous supply of energy and building materials as well as elimination of waste products (metabolism). In the last resort, metabolism serves the repair or prevention of damage continuously occurring in metabolites and structures as a result of chemical reactions and physical damage. However, as a consequence of diseases and slowly proceeding age-related changes, repair cannot sufficiently keep step with its demand. Furthermore, it is repair processes that produce damage in the long run, the result being eventual failure of life processes. The causal mechanisms are often compared to a “biological clock”. Decrease in body temperature is the key.Decrease in body temperature leads to retardation of metabolic- as well as damaging processes and decrease of food and energy demand. This type of hibernation however, is no simple process. It needs a pattern of gene action shifting metabolism and the production of cryoprotective substances in the body. In man this option is not programmed by the genes. As many other warm-blooded animals his organism is unsuited for winter sleep. To some extend cooling already works even in human beings. By decreasing temperature (hypothermia), heart surgeons are able to stop heartbeat for 30 min or longer without remaining damage. However, temperatures for such hypothermia are well above the freezing point (of water). Choosing very low temperatures like those of liquid nitrogen, metabolism cannot longer be observed and living tissue is maintained almost unchanged over long times (orders of 10000 to millions of years). Thus the biological clock has been stopped. Reduction of life processes engendered by cooling is named cryostasis representing a special type of biostasis. Even the human body could be transported to a distant future by such means, almost without being affected by any harmful changes at all. This procedure could become important e.g. for long space travels. But would it really be possible to revive the cryopreserved person in the future?Methods of freezing cell culture cells represent evidence for the fact that life can endure cooling of up to –196°C (the temperature of liquid nitrogen). Moreover, thousands of people living today have developed from frozen and thawed embryos and microscopically small multi-cellular living entities that have been revived after cooling to the temperature of liquid nitrogen. Unfortunately, today complete human organisms as well as mammalian ones cannot be re-suspended yet. Therefore, it is not clear in detail, how the respective applied cooling method affects the human body in terms of damage. In the first place, huge body size is responsible for difficulties, since warming or cooling of the organism reach the core of our body relatively slowly (ice outside, damage inside) compared to smaller organisms. In addition, man is composed of a multiplicity of tissues with different densities and temperature conduction, not to forget that different cells of the tissues differ in sensitivity against temperature changes. This holds true for cooling as well as for re-warming. Therefore, today’s cryonics mainly concentrates on preservation of one single organ, namely the brain, which is very sensible on the one hand and responsible for our consciousness on the other. For the present, cryonics remains an emergency measure, and is not applied to living people. Besides technical obstacles there exists a by far more serious barrier regarding awaking cryonically-preserved people however. In countries with highly developed technology, people only die in case of damage to their bodies to such an extent that current medicine is unable to repair it. Apart from this, damage will proceed after body re-warming, if one has not learned before to stop it. Cryonics can only be proven in the future.Cryonicists refuse waiting for maturation of all methods. They intend instead to preserve their bodies as long as this is still possible to protect it against further damaging changes by cryostasis. A long term goal of cryonics consists in the maintenance of total human bodies in cryostasis at the temperature of liquid nitrogen, to revive them in the future. Hope is allowed in further progress in science and medicine, which allows for revival as well as elimination of the relics of diseases and aging as well as freezing damage in the future. The more effective our techniques of cryostasis are working today, the more such hope is well-founded. Thus, cryonics can be taken to be an anticipated application of cryobiological methods which is to leave evidence of practicability to the future. Similar to physicians, cryonicists show very individualized motivations in this field to devote themselves to the advancement of these methods.
Cryonics makes huge progress.While conventional cryobiology perfects especially cryopreservation of cell cultures and blood cells, cryobiologists interested in cryonics turned to the preservation of large parts of tissue, an undertaking initially seeming almost without prospects. Following impregnation with solutions of valid cryoprotectants and substances to stop ice crystals (ice blockers) while being only marginally toxic and allow for slow continuous cooling, in the last years (recent) substantial progress has been made not only cooling separated cells to deep temperatures, but even larger entities, namely brain slices of high diameter and complete organs of small mammals. Functions were completely or almost completely maintained following such procedures. Chosen temperatures however have not been sufficiently low or the lowest temperatures could be maintained only during short periods of time. The application of cryobiological methods in de-animated human beings has also led to experiences and registration of lots of data, which can only be acquired this way and which add substantially to extend medical knowledge today. In the meantime, the feasibility of similar processes has also been demonstrated in artificial hibernation (suspended animation) another variant of biostasis. Recently highly developed mammals like rats and dogs have been brought back to normal life following hours of cardiac arrest. This has been rendered possible by stop of metabolism using cooling and depletion of oxygen. Cryonics stops time, until medicine is ready.Finally, there are two major points of importance concerning cryonics that need to be emphasized:
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