astrocytosis

as·tro·cy·to·sis

(as'trō-sī-tō'sis),
An increase in the number of astrocytes, frequently observed in an irregular zone of variable definition adjacent to degenerative lesions (for example, encephalomalacia), focal inflammations (for example, abscesses), or certain neoplasms in the brain; in some instances, astrocytosis may be diffuse in a relatively large region; astrocytosis represents a reparative mechanism.

astrocytosis

[as′trōsītō′sis]
Etymology: Gk, aster + kytos + osis, condition
an increase in the number of neuroglial cells with fibrous or protoplasmic processes frequently observed in an irregular area adjacent to degenerative lesions, such as abscesses, certain brain neoplasms, and encephalomalacia. Astrocytosis represents a reparative process and in some cases may be diffuse in a large region.
References in periodicals archive ?
In mice showing only plaque-like deposits of PrP, there was no association between astrocytosis and PrP deposition and no evidence of reactive astrocytosis (Figure 5).
The increased or "reactivated" astrocytes, in a process called astrocytosis, play a role in secondary injury following neurotrauma [42], and astrocytosis could be an early sign of chronic traumatic encephalopathy [27].
Continuance of chorea despite normalization of blood glucose in some patients and the fact that abnormal movements are generally observed on the one side of the body are contradictory to a metabolic pathology, while the fact that chorea may be observed bilaterally and observation of only neuron loss, gliosis and reactive astrocytosis, but not infarction or hemorrhagia are contradictory to vascular pathology (9,10).
Neuropathological features of TME include spongiform degeneration in the neuropil of the brain, astrocytosis and the formation of PrP deposits of the TME agent.
Abnormal neuronal migration, deranged cerebral cortical organization and diffuse white matter astrocytosis of human fetal brain: A major effect of methylmercury poisoning in utero.
Mutant IDH1-specific immunohistochemistry distinguishes diffuse astrocytoma from astrocytosis.
Furthermore, quantitative immunohistochemistry demonstrated time-related statistically significant increases in amyloid immunoreactivity, tau phosphorylation, microglial activation, and astrocytosis.
The adjacent brain tissue demonstrated astrocytosis and evidence of old hemorrhage, characterized by blood degradation products including hemosiderin.
The impact of reactive astrocytosis on brain function is difficult to investigate because it usually occurs in the context of brain inflammation and abnormal changes in surrounding cells.
Cellular and extracellular inhibitors are thought to restrict axon growth after chronic spinal cord injury, confronting the axon with a combination of chronic astrocytosis and extracellular matrix-associated inhibitors that collectively constitute the chronic "scar" 61.
While active lesions are defined pathologically by the presence of partially myelinated axons in tissue infiltrated by numerous myelin-laden macrophages, (7) the morphological features of an individual plaque are often complex, and may additionally comprise zones of oligodendrocyte apoptosis or loss, myelin pallor or vacuolation, normal or aberrant remyelination, microglial activation and reactive astrocytosis.
Prions accumulate in neurological tissue and pathological examination shows a classic sponge-like appearance created in the brain by microscopic vacuoles, deposition of amyloid plaques, neuronal loss and astrocytosis.