Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.2.1.31 (beta-glucuronidase)
 7,680 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Granule laden astrocytes exhibiting an affinity for chrome alum hematoxylin and aldehyde fuchsin (Gomori stains) have been described in the periventricular brain of all terrestrial vertebrate species examined to date including humans. The astrocytic inclusions are rich in sulfhydryl groups, emit an orange-red autofluorescence, and stain intensely with diaminobenzidine, a marker of endogenous peroxidase activity. The distinct autofluorescence pattern and the absence of neutral lipid, acid phosphatase, and beta-glucuronidase activity exclude lipofuscin or lysosomes as components of these astrocytic granules. The emission of orange-red autofluorescence and the nonenzymatic nature of the peroxidase activity implicate the presence of porphyrins and metalloporphyrins such as heme as major constituents of these cytoplasmic gliosomes. The role of Gomori-positive astrocytes under normal and pathologic conditions is incompletely understood. In vivo, numbers of astrocytic granules increase as a function of advancing age, in response to chronic estrogen stimulation, and following X-irradiation. In vitro, these cells accumulate with increasing time in culture and following exposure to the sulfhydryl agent, cysteamine. Gomori-positive astrocytes may supply heme to neurons for the synthesis of cytochromes, catalases, and other heme enzymes. They may play a role in photostimulation of sexual cyclicity, the promotion of neuritic development, the degradation of toxic lipoperoxides, and the metabolism of various neurotransmitters. Conversely, these cells may contribute to the pathogenesis of several neurologic and neuroendocrine disorders. Examples of the latter include a) augmentation of goldthioglucose neurotoxicity, b) induction of hypothalamic anovulation and reproductive failure, c) exacerbation of porphyric encephalopathy, and d) potentiation of parkinsonism and other free radical-related neurodegenerations.
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PMID:Gomori-positive astrocytes: biological properties and implications for neurologic and neuroendocrine disorders. 171 59

Enzyme activity changes in reagent and neoplastic glia are examined. In the case of reagent glia, considerably increased ADPase, ATPase and AMPase values have been observed in experimental elective parenchymal necrosis in the rat, in hypertrophic astrocytes from recent plaques in multiple necrosis, in demyelinisation associated with cyanide encephalopathy, and in reagent astrocytes surrounding tumours and arteriosclerosis sites. Depressed ATPase values have been observed in experimental oedema, as compared with increased TPPase in human oedema. BuChE and ChE activity disappears in both oligodendro- and astroglia near old cerebral infarct sites, whereas there is marked BuChE activity peripherally to multiple sclerosis plaques and in areas of phenylpyruvic oligophrenia demyelinisation. In neoplastic glia, ADPase is clearly evident in malignant gliomas, ATPase is related to the extent of the cell body, AMPase is positive in medulloblastoma cell cytoplasm and beta-glucuronidase increases in anaplasia. Above-normal ChE activity has been observed in astrocyte tumors, while BuChE is greater than that of AChE. Phosphorylase reaction is intense in astrocytoma and in glioblastoma giant cells. Phosphoglucomutase values are below-normal in tumours, except in the case of ependymoma, while both phosphohexoisomerase and hexokinase display increased activity in atypical forms.
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PMID:[Histochemical demonstration of glial enzyme activity. II. Reagent and neoplastic glia]. 1734 Aug 8