necrosis

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necrosis

1. the death of one or more cells in the body, usually within a localized area, as from an interruption of the blood supply to that part
2. death of plant tissue due to disease, frost, etc.
Collins Discovery Encyclopedia, 1st edition © HarperCollins Publishers 2005
The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.

Necrosis

 

the death within the living organism of individual organs or their component tissues or cells.

A necrosis is classified according to the pathological condition that causes it. Thus, frostbite and burns can cause traumatic necrosis; neurotropic necrosis arises with syringomyelia and the nervous form of leprosy; infarcts and gangrene are associated with circulatory, or ischemic, necrosis; caseous necroses occurring in tuberculosis and syphilis are forms of septic necrosis; and fibrinoid necrosis associated with allergic diseases is a type of allergic necrosis.

Necrosis is accompanied by characteristic changes in the cell and in the intercellular substances. The nucleus shrinks and coagulates, a process known as pycnosis, and the cytoplasm breaks up into clumps. The cell eventually lyses, that is, it degenerates and dissolves. The lysis is due to the activation of the lysosomal hydrolytic enzymes, such as ribonuclease, deoxyribonuclease, and acid phosphatase. The activation of the lysosomes occurs as a result of an increase in the permeability of the cell membranes, changes in the osmotic equilibrium, and acidosis—an abnormal increase in the intracellular hydrogen-ion concentration. Fibrinoid changes appear in the connective tissue, and nerve fibers become fragmented and disintegrate into clumps.

The clinical and morphological manifestations and further consequences of necrosis depend on the localization and distribution of the necrosis and on the mechanisms and conditions of origin. The following types of advanced necrotic conditions can develop: dry necrosis, such as Zenker’s degeneration of infected muscles; colliquative, or liquefactive, necrosis, which occurs for example, when a focus of softening arises in the brain in response to cerebral hemorrhage; gangrene; and bed sores. Necrotic tissue tears away; then, either connective tissue grows through it or the necrotic tissue undergoes autolytic or purulent liquefaction. Finally, the necrotic tissue becomes encapsulated and petrified.

The two most serious consequences of necrosis are a loss of function owing to the death of the structural elements of the necrotic tissues or organs and poisoning caused by the actual presence of a necrotic focus and by the inflammation that arises in response to this presence.

V. V. SEROV

The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.

necrosis

[nə′krō·səs]
(medicine)
Death of a cell or group of cells as a result of injury, disease, or other pathologic state.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
References in periodicals archive ?
Avascular necrosis after internal fixation of intracapsular hip fractures: a study of the outcome for 1,023 patients.
The presence of avascular necrosis had no statistical association with outcome [34].
Avascular necrosis after surgical treatment for development dysplasia of the hip.
The use of alendronate in the treatment of avascular necrosis of the femoral head: follow-up to eight years.
Table: Ficat Classification of avascular necrosis of femoral head.
Gandhi, "Stem cell therapy for the treatment of early stage avascular necrosis of the femoral head: a systematic review," BMC Musculoskeletal Disorders, vol.
* Based on change in largest diameter, PR = partial response, SD = stable disease, and AVN = avascular necrosis. Table 2: Selected previous studies of desmoid tumors treated with imatinib or radiation therapy alone.
We wanted to study if modified Dunn procedure restores the normal alignment of the proximal femur and the risk of avascular necrosis is increased.
There are 155 chapters divided into 14 sections: anatomy and approaches; pediatric elbow and forearm fractures and dislocations; elbow fractures and dislocations; forearm and wrist fractures and dislocations; carpal fractures and avascular necrosis; hand fractures and dislocations; instability; tendon injuries and disorders; nerve injury and compression; arthritis; compartment syndrome, vascular disorders, and infection; contractures, thermal injuries, and tissue loss; tumors; congenital forearm, wrist, and hand disorders.
Zameer Shah, a leading specialist, says the treatment has the potential to be 'life-changing' for those with bone disease avascular necrosis (AVN).