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Cryopreservation or cryoconservation is a process where biological material - cells, tissues, or organs - are frozen to preserve the material for an extended period of time. [1] At low temperatures (typically −80 °C (−112 °F) or −196 °C (−321 °F) using liquid nitrogen ) any cell metabolism which might cause damage to the biological ...
At least six major areas of cryobiology can be identified: 1) study of cold-adaptation of microorganisms, plants (cold hardiness), and animals, both invertebrates and vertebrates (including hibernation), 2) cryopreservation of cells, tissues, gametes, and embryos of animal and human origin for (medical) purposes of long-term storage by cooling to temperatures below the freezing point of water.
Typical specimens for cryofixation include small samples of plant or animal tissue, cell suspensions of microorganisms or cultured cells, suspensions of viruses or virus capsids and samples of purified macromolecules, especially proteins. [2] [3] Types of cryo-fixation are freezing-drying, freezing-substitution and freezing-etching.
coagulation of blood thereby interrupting bloodflow to the tissue in turn causing ischemia and cell death; and induction of apoptosis , the so-called programmed cell death cascade. The most common application of cryoablation is to ablate solid tumors found in the lung, liver, breast, kidney and prostate.
Freeze drying, also known as lyophilization or cryodesiccation, is a low temperature dehydration process [1] that involves freezing the product and lowering pressure, thereby removing the ice by sublimation. [2] This is in contrast to dehydration by most conventional methods that evaporate water using heat. [3]
Additionally, as the cells shrink, the solutes inside the cells are concentrated in the remaining water, increasing the intracellular ionic strength and interfering with the organization of the proteins and other organized intercellular structures. Eventually, the solute concentration inside the cells reaches the eutectic and freezes.
Medical laboratories have long used cryopreservation to maintain animal cells, human embryos, and even some organized tissues, for periods as long as three decades. [30] But recovering large animals and organs from a frozen state is not considered possible now.
In the fields of histology, pathology, and cell biology, fixation is the preservation of biological tissues from decay due to autolysis or putrefaction.It terminates any ongoing biochemical reactions and may also increase the treated tissues' mechanical strength or stability.