question: why is keeping ice on the skin bad, but keeping organs on ice preserves them?
comment: Because they're not placed directly on ice. Great care is taken not to damage them and they're usually wrapped in some form of protective film
passages: Section::::Applications.:Medicine.
  
  A protective cooling process based on the implementation of a developed special ice slurry has been developed for medical applications. In this case pumpable ice can be injected intra-arterially, intravenously, along the external surfaces of organs using laparoscopy, or even via the endotracheal tube. It is being confirmed that pumpable ice can selectively cool organs to prevent or limit ischemic damage after a stroke or heart attack. Completed medical tests on animals simulated conditions requiring in-hospital kidney laparoscopic procedures. Results of French and US research are yet to be approved by the U.S. Food and Drug Administration.
   “The water freezes and the germs are in the water. The freezing does not kill the germs for they are very resistant to cold and they remain in the ice until liberated by its melting when placed in water, or milk, or in contact with food taken into the system.
  
  “Upon the other hand, artificial ice being produced from distilled water, which is practically sterile, there can be no contamination.”
  
  Artificial ice could be made all year and didn’t depend on the whims of nature. Furthermore, it was a lot cleaner.
   Therapeutic hypothermia, e.g. during heart surgery on a "cold" heart (generated by cold perfusion without any ice formation) allows for much longer operations and improves recovery rates for patients.
  
  Section::::Scientific societies.
   The beneficial effect of hypothermia on ischaemic intact kidneys was demonstrated by Owens in 1955 when he showed that, if dogs were cooled to 23-26 °C, and their thoracic aortas were occluded for 2 hours, their kidneys showed no apparent damage when the dogs were rewarmed. This protective effect of hypothermia on renal ischaemic damage was confirmed by Bogardus who showed a protective effect from surface cooling of dog kidneys whose renal pedicles were clamped in situ for 2 hours. Moyer demonstrated the applicability of these dog experiments to the human, by showing the same effect on dog and human kidney function from the same periods of hypothermic ischaemia.
   Many workers have attempted to prevent kidneys rewarming during reimplantation but only Cohen has described using a system of active cooling. Measurements of lysosomal enzyme release from kidneys subjected to sham anastomoses, when either in or out of the cooling system, demonstrated how sensitive kidneys were to rewarming after a period of cold storage, and confirmed the effectiveness of the cooling system in preventing enzyme release. A further factor in minimising injury at the reimplantation operations may have been that the kidneys were kept at 7 °C within the cooling coil, which was within a degree of the temperature used during perfusion storage, so that the kidneys were not subjected to the greater changes in temperature that would have occurred if ice cooling had been used.
   Benefits of pumpable ice technology in medicinal applications are:
  
  BULLET::::1. Pumpable ice can be pumped easily through narrow catheters, providing high cooling capacity and rapid and targeted cooling of organs;
  
  BULLET::::2. Pumpable ice may provide protective cooling and temperature management of target organs during surgery;
  
  BULLET::::3. Pumpable ice helps victims of such medical emergencies as cardiac arrest and stroke.
  
  Section::::Applications.:Ski resorts.
   Cryotherapy, the use of ice or cold in a therapeutic setting, has become one of the most common treatments in orthopedic medicine. The primary reason for using cryotherapy in acute injury management is to lower the temperature of the injured tissue, which reduces the tissue's metabolic rate and helps the tissue to survive the period following the injury. It is well documented that metabolic rate decreases by application of cryotherapy.
   Section::::Physical treatments.
  
  The most common physical methods used to lyse, kill, and remove cells from the matrix of a tissue through the use of temperature, force and pressure, and electrical disruption. Temperature methods are often used in a rapid freeze-thaw mechanism. By quickly freezing a tissue, microscopic ice crystals form around the plasma membrane and the cell is lysed. After lysing the cells, the tissue can be further exposed to liquidized chemicals that degrade and wash out the undesirable components. Temperature methods conserve the physical structure of the ECM scaffold, but are best handled by thick, strong tissues.
   Section::::Results.
  
  Cryosurgery is a minimally invasive procedure, and is often preferred to more traditional kinds of surgery because of its minimal pain, scarring, and cost; however, as with any medical treatment, there are risks involved, primarily that of damage to nearby healthy tissue. Damage to nerve tissue is of particular concern.
   Section::::Organs.:Brain-on-a-chip.:Limitations.
  
  Brain-on-a-chip devices can cause shear stress on cells/tissue due to flow through small channels, which can result in cellular damage. These small channels also introduce susceptibility to the trapping of air bubbles that can disrupt flow and potentially cause damage to the cells. The widespread use of PDMS (Polydimethylsiloxane) in brain-on-a-chip devices has some drawbacks. Although PDMS is cheap, malleable, and transparent, proteins and small molecules can absorb to it and later leech at uncontrolled rates.
  
  Section::::Organs.:Lung-on-a-chip.
   The risk of a loss of body temperature and hypothermia increase with the duration of surgery, especially for surgery that lasts more than one hour. Surgical hypothermia, defined as a core temperature below 36.0 °C, is associated with increased risk of infectious and non-infections complications, longer post-operative ICU and overall hospital recovery, and more frequent requirement of transfusions. Elderly persons, especially those with lower muscle and body mass are at greater risk of hypothermia.
   Different catheter-based ablation techniques may be used and they generally fall into two categories: (1) cold-based procedures where tissue cooling is used to treat the arrhythmia, and (2) heat-based procedures where high temperature is used to alter the abnormal conductive tissue in the heart.
  
  Section::::Catheter-based procedures.:Cryoablation.
  
  Cold temperatures are used in cryoablation to chill or freeze cells that conduct abnormal heart rhythms. The catheter removes heat from the tissue to cool it to temperatures as low as -75 °C. This causes localized scarring, which cuts undesired conduction paths.
   Ice baths are a part of a broader phenomenon known as cryotherapy—the Greek word "cryo" (κρυο) means "cold"—which describes a variety of treatments when cold temperatures are used therapeutically. Cryotherapy includes procedures where a person is placed in a room with "cold, dry air at temperatures as low as −135 °C" for short periods of time, and which has been used in hospitals in Poland as well as a center in London to treat not only muscular ailments, but psychological problems such as depression. Basketball player Manny Harris reportedly used a Cryon-X machine featuring extreme low temperatures around minus 166 degrees Fahrenheit, but used it with wet socks resulting in a serious freezer burn.
   Cryolipolysis is a method to remove fat by freezing. The method involves controlled application of cooling within the temperature range of -11 to +5 °C for the non-invasive, localized reduction of fat deposits, intending to reshape the contours of the body. The degree of exposure to cooling causes cell death of subcutaneous fat tissue, without apparent damage to the overlying skin. It appears primarily applicable to limited discrete fat bulges. Adverse effects include transient local redness, bruising and numbness of the skin are common side effects of the treatment and are expected to subside. Typically sensory deficits will subside within a month. The effect on peripheral nerves was investigated and failed to show permanent detrimental results.
   Laparoscopic cryotherapy can also be done on smaller lesions. Typically a biopsy is taken at the time of treatment. Intraoperative ultrasound may be used to help guide placement of the freezing probes. Two freeze/thaw cycles are then performed to kill the tumor cells. As the tumor is not removed followup is more complicated (see below) and overall disease free rates are not as good as those obtained with surgical removal.
   The rate of cooling of a tissue may also be significant in the production of injury to enzyme systems. Francavilla showed that when liver slices were rapidly cooled (immediate cooling to 12 °C in 6 minutes) anaerobic glycolysis, as measured on rewarming to 37 °C, was inhibited by about 67% of the activity that was demonstrated in slices that had been subjected to delayed cooling. However, dog kidney slices were less severely affected by the rapid cooling than were the liver slices.
  
  Section::::Nature of kidney preservation injury.:Mechanisms of injury.:Metabolic injury.:Anoxia.
   If surgery is explorative, rapid examination of a lesion might help identify the possible cause of a patient's symptoms. It is important to note, however, that the pathologist is very limited by the poor technical quality of the frozen sections. A final diagnosis is rarely offered intraoperatively.
   When ablating tissue near the AV node (a special conduction center that carries electrical impulses from the atria to the ventricles), there is a risk of producing heart block – that is, normal conduction from the atria cannot be transmitted to the ventricles. Freezing tissue near the AV node is less likely to provoke irreversible heart block than ablating it with heat.
  
  Section::::Surgical procedures.
   Section::::Whole body cryotherapy.:Adverse effects.
  
  Reviews of whole body cryotherapy have called for research studies to implement active surveillance of adverse events, which are suspected of being underreported. If the cold temperatures are produced by evaporating liquid nitrogen, there is the risk of inert gas asphyxiation as well as frostbite.
  
  Section::::Whole body cryotherapy.:Partial body.
  
  Partial body cryotherapy (PBC) devices also exist. If the cold temperatures are produced by evaporating liquid nitrogen, there is the risk of inert gas asphyxiation as well as frostbite.
  
  Section::::See also.
  
  BULLET::::- Cryonics
  
  BULLET::::- Cold shock response
  
  BULLET::::- Cold compression therapy
  
  Section::::External links.
   CLARITY can be used with little or no modifications to clear most other organs such as liver, pancreas, spleen, testis, and ovaries and other species such as zebrafish. While bone requires a simple decalcification step, similarly, plant tissue requires an enzymatic degradation of the cell wall.
  
  NIH director Francis Collins has already expressed his hopes for this emergent technology, saying: 
  
  Section::::Limitations.
   With some exceptions, the formation of ice within cells generally causes cell death even in freeze-tolerant species due to physical stresses exerted as ice crystals expand. Ice formation in extracellular spaces is also problematic, as it removes water from solution through the process of osmosis, causing the cellular environment to become hypertonic and draw water from the cell interiors. Excessive cell shrinkage can cause severe damage. This is because as ice forms outside the cell, the possible shapes that can be assumed by the cells are increasingly limited, causing damaging deformation. Finally, the expansion of ice within vessels and other spaces can cause physical damage to structures and tissues.
   There is evidence that immunological mechanisms may injure hypothermically perfused kidneys after reimplantation if the perfusate contained specific antibody. Cross described two pairs of human cadaver kidneys that were perfused simultaneously with cryoprecipitated plasma containing type specific HLA antibody to one of the pairs. Both these kidneys suffered early arterial thrombosis. Light described similar hyperacute rejection following perfusion storage and showed that the cryoprecipitated plasma used contained cytotoxic IgM antibody. This potential danger of using cryoprecipitated plasma was demonstrated experimentally by Filo who perfused dog kidneys for 24 hours with specifically sensitised cryoprecipitated dog plasma and found that he could induce glomerular and vascular lesions with capillary engorgement, endothelial swelling, infiltration by polymorphonuclear leucocytes and arterial thrombosis. Immunofluorescent microscopy demonstrated specific binding of IgG along endothelial surfaces, in glomeruli, and also in vessels. After reimplantation, complement fixation and tissue damage occurred in a similar pattern. There was some correlation between the severity of the histological damage and subsequent function of the kidneys.
   Further attempts to alleviate the problem by declaring, in stages, cryogenically frozen people to be dead in law (the so-called "Freezer Bills") and harvesting their organs also proved to be unsuccessful. The freezer vaults represented a finite supply and therefore were eventually exhausted.
   A rule of thumb in hypothermic storage is that every 10 °C reduction in temperature is accompanied by a 50% decrease in oxygen consumption. Although hibernating animals have adapted mechanisms to avoid metabolic imbalances associated with hypothermia, hypothermic organs, and tissues being maintained for transplantation require special preservation solutions to counter acidosis, depressed sodium pump activity. and increased intracellular calcium. Special organ preservation solutions such as Viaspan (University of Wisconsin solution), HTK, and Celsior have
  
  been designed for this purpose. These solutions also contain ingredients to minimize damage by free radicals, prevent edema, compensate for ATP loss, etc.
   Section::::Nature of kidney preservation injury.:Mechanisms of injury.:Metabolic injury.
  
  Section::::Nature of kidney preservation injury.:Mechanisms of injury.:Metabolic injury.:Cold.
  
presuppositions: Organs are placed directly on ice to preserve them. Placing organs on ice preserves them
corrections: Organs preserved on ice are wrapped in a protective film. Organs are not placed directly on ice. They are wrapped in some protective film.
raw_presuppositions: Organs are placed directly on ice to preserve them. Placing organs on ice preserves them
raw_corrections: Organs preserved on ice are wrapped in a protective film. Organs are not placed directly on ice. They are wrapped in some protective film.