Cryostat

A chamber that can maintain very low temperatures. Medical laboratories use a cryostat to preserve frozen tissue samples while a microtome, an extremely sharp cutting instrument mounted inside cryostats, slices the tissue into pieces thin enough to be observed under a microscope. The sliced piece must be so thin as to look nearly transparent. A pathologist, a laboratory doctor trained to identify evidence of disease in microscopic structures, then examines the slice to confirm or rule out the presence of a disease, such as cancer. Use of frozen tissue samples enables physicians to examine tissue and diagnose its condition more quickly than if the tissue had been preserved without freezing. Microtomes may be used alone, without cryostats, to yield thin microscopic samples. For example, researchers have used microtomes to remove samples from the Shroud of Turin, a linen cloth imprinted with a negative photographic image of a man. Many Christians believe this shroud was the burial cloth of Jesus Christ, who was said to have imprinted his image on it miraculously. The microscopic samples taken with a microtome have been used to attempt to prove or disprove the validity of belief. "Cryostat" is derived from the Greek "kryos" (cold) and "statos" (standing, stationary, like the cryostat chamber). "Kryos" gives us many English words, such as "cryonics" (use of coldness in medicine to bring about beneficial results) and "cryosurgery" (use of below- freezing temperatures to destroy disease). "Statos" and related Greek words give us such English words as "static" and "stationary."

* * *

A freezing chamber. [cryo- + G. statos, standing]

* * *

cryo·stat 'krī-ə-.stat n an apparatus for maintaining a constant low temperature esp. below 0°C (as by means of liquid helium) esp one containing a microtome for obtaining sections of frozen tissue

cryo·stat·ic .krī-ə-'stat-ik adj

* * *

n.

1. a chamber in which frozen tissue is sectioned with a microtome.

2. a device for maintaining a specific low temperature.

* * *

cryo·stat (kriґo-stat″) [cryo- + -stat] 1. a device by which temperature can be maintained at a very low level. 2. in pathology and histology, a chamber containing a microtome for sectioning frozen tissue.