Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:2.7.1.1 (hexokinase)
 5,274 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

To estimate hemocirculation and proliferating activity of intraventricular tumor, we measured kinetic rate constants (k1, k2, k3) and glucose metabolic rate (kinetic-rCMRGl) using dynamic positron emission tomography (PET), as well as regional cerebral blood flow (rCBF), blood volume (rCBV), oxygen extraction fraction (rOEF), oxygen metabolic rate (rCMRO2) and autoradiographic rCMRGl (arg-rCMRGl), in patients with intraventricular tumor. The subjects included ten patients, five males and five females, aged from 13 to 53 years with a mean age of 32 years old. Eight tumors were located in the lateral ventricle and two extended into the third ventricle through the foramen of Monro. Another two tumors were located in the fourth ventricle. Histological diagnosis was as follows: five cases of central neurocytoma, one subependymal giant cell astrocytoma, one ependymoma, one choroid plexus carcinoma, one subependymoma, and one meningioma. Tumor lesion on the PET images was determined using CT or MRI, which was performed at levels equivalent to those for the PET scans. For quantitative analysis, regions of interest (ROI) on PET images were delineated on the tumor and the contralateral gray matter. Hemocirculation (rCBF, rCBV) of the tumor was similar to or higher than that of the contralateral gray matter, which corresponded to neuroradiological findings of abundant tumor vessels. Oxygen metabolic parameters (rOEF, rCMRO2) were significantly lower than those of the contralateral gray matter. Especially, low rOEF resulted in an excessive blood flow beyond oxygen demand of the tumor. The raised metabolic rate (rCMRO2/rCMRGl), as compared with that of meningiomas or malignant gliomas, suggested aerobic glycolysis. The kinetic rate constants of tracer transport from blood to brain (k1), reverse transport from brain to blood (k2), and phosphorylation (k3) were analyzed according to the three-compartment model of 18F-fluorodeoxyglucose (18FDG). Tumor k1 and k2 values were similar to or higher than those of the contralateral gray matter, suggesting high permeability due to lack of blood-brain barrier and an abundant blood supply. Tumor k3 value, an indicator of hexokinase activity, and kinetic-rCMRGl were lower in six of eight patients. These six patients have been free from tumor recurrence or regrowth, postoperatively. In the other two patients, tumor kinetic-rCMRGl was similar to or higher than that of the contralateral gray matter, suggesting high activity of proliferation. However, one patient received irradiation and has been followed up, and the other received total resection and has shown no recurrence. Functional information concerning intraventricular tumor is obtained by PET analysis, and kinetic analysis of the rate constants is useful for interpreting a detailed metabolic process of glucose, and provides additional information on intraventricular tumor aggressiveness.
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PMID:[Hemocirculation and metabolism in intraventricular tumors: kinetic analysis of glucose metabolism]. 885 49

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