Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0017638 (glioma)
 30,880 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Brain tumor metabolism was studied with hydrogen-1 magnetic resonance spectroscopy and positron emission tomography with fluorine-18 fluorodeoxyglucose in 50 patients. N-acetylaspartate (NAA) was generally decreased in tumors and radiation necrosis but was somewhat preserved at neoplasm margins. Choline was increased in most solid tumors. Solid high-grade gliomas had higher normalized choline values than did solid low-grade gliomas (P < .02), but the normalized choline value was not a discriminator of tumor grade, since necrotic high-grade lesions had reduced choline values. Serial studies in one case showed an increase in choline as the glioma underwent malignant degeneration. Choline values were lower in chronic radiation necrosis than in solid anaplastic tumors (P < .001). In two cases studied before and after treatment, clinical improvement and a reduction in choline followed therapy. Lactate is more likely to be found in high-grade gliomas, but its presence is not a reliable indicator of malignancy.
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PMID:Mapping of brain tumor metabolites with proton MR spectroscopic imaging: clinical relevance. 143 44

The 2- and 6-fluoro derivatives of the potent beta-adrenergic agonist 3-(tert-butylamino)-1-(3,4-dihydroxyphenoxy)-2-propanol were prepared and their adrenergic properties examined. The order of potency was as follows: beta-adrenergic activity (simulation of cyclic AMP formation in C6 glioma cells), 2-F = parent much greater than 6-F; beta 1-activity (rate of contraction, guinea pig atria), parent greater than 2-F much greater than 6-F; beta 2-activity (relaxation of guinea pig tracheal strip), 2-F greater than parent much greater than 6-F. The affinity of the 2-fluoro analogue for beta 1-adrenergic receptors (inhibition of the specific binding of [3H]dihydroalprenolol, rat cerebral cortical membranes) was 2 times greater, while the 6-fluoro analogue was 1450 times less than the parent. These results suggest that the aromatic rings of phenoxypropanolamine adrenergic agonists and phenylethanolamine adrenergic agonists bind in similar fashion to the adrenergic receptor, and that if interactions between fluorine and the side-chain hydroxyl group are critical in defining beta-adrenergic selectivity, the interactions are similar in both phenoxypropanolamines and phenylethanolamines.
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PMID:Effect of fluorine substitution on the adrenergic properties of 3-(tert-butylamino)-1-(3,4-dihydroxyphenoxy)-2-propanol. 167 55

Treatment of neuroblastoma x glioma hybrid, NG108-15, cells with prostaglandin E1, which in these cells activates adenylate cyclase, produced a marked (50%) reduction in immunologically detectable levels of Gs alpha associated with the plasma membrane. This effect was dependent both on the time of treatment and on the concentration of the receptor ligand used and did not involve a translocation of Gs alpha from the membrane to the cytoplasm of the cells. Both the 45- and 42-kDa forms of Gs alpha which are expressed by these cells were reduced in levels by treatment with the agonist but the greater effect was on the more prevalent 45-kDa polypeptide. By contrast, treatment of the cells with forskolin over the same period did not produce a reduction in levels of Gs alpha, indicating that the effect of prostaglandin E1 was independent of cAMP production. Prostaglandin E1-mediated down-regulation of Gs alpha levels was not produced at the transcriptional level as amounts of mRNA encoding Gs alpha were not reduced by treatment of the cells with agonist. Further, treatment of NG108-15 cells with cycloheximide, throughout the time period required to produce maximal prostaglandin E1-dependent down-regulation of Gs alpha, demonstrated that complete suppression of de novo protein synthesis could not mimic the effect of prostaglandin E1 and hence even complete inhibition of transcription of the Gs alpha gene and/or translation of pre-existing mRNA could not account for these results. Prostaglandin E1 treatment of the cells had no effect on steady-state levels of the alpha subunits of the pertussis toxin-sensitive G-proteins, Gi2, Gi3, Go, which are expressed by these cells or on the level of G-protein beta subunit. Fluoride stimulation of adenylate cyclase activity in membranes of S49 cyc- cells following addition of sodium cholate extracts of membranes of prostaglandin E1-treated NG108-15 cells was only some 50% as effective as with equivalent extracts from untreated cells. These results provide evidence for a novel mechanism of receptor-mediated control of the stimulation of adenylate cyclase, involving reduction in the steady-state amounts of Gs alpha.
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PMID:Prostaglandin E1-mediated, cyclic AMP-independent, down-regulation of Gs alpha in neuroblastoma x glioma hybrid cells. 217 Mar 66

The intrinsic resolution of the Donner 600-crystal positron emission tomograph (PET 600) is 2.6 mm full width at half maximum (FWHM) in-plane and 6 mm FWHM axially. More than 100 patients with glioma, radiation necrosis, Alzheimer disease, or epilepsy have been studied with this system. Approximately 1 million events are acquired in 15 minutes, starting 1 hour after injection of 10 mCi (370 MBq) of fluorine-18-fluorodeoxyglucose. Normal structures as small as the superior colliculi and the external capsule have been resolved. Improved separation of the cortical ribbon from adjacent white matter has allowed more accurate determination of cortical metabolic rate. In two of 15 patients undergoing evaluation for recurrent glioma, the PET 600 images showed tumor uptake that was not apparent on a lower-resolution study. A high-activity orbiting transmission source with electronic collimation allows accurate, short-duration transmission measurements to be made after radiopharmaceutical administration. The anatomic detail seen on the transmission images can be used for reproducible patient positioning with an accuracy of 1-2 mm perpendicular to the image plane. These findings demonstrate the practicality and clinical effectiveness of high-resolution positron emission tomography.
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PMID:Clinical evaluation of a high-resolution (2.6-mm) positron emission tomography. 238 37

Computerized tomography (CT) and positron emission tomography (PET) using fluorine-18-deoxyglucose were performed in a patient with malignant glioma over a one-year period. Postoperatively and during radiation therapy, there was slight improvement in metabolic activity in the hemisphere ipsilateral to the tumor. After radiation therapy and during chemotherapy, there was a rapid and then gradual decline in whole brain metabolic rate by 39%. This might have been explained by radiation effect on brain. The tumor area was metabolically similar to the adjacent brain until one year after diagnosis, when an area of abnormal increased activity was noted. Even though CT scans showed minimal evidence of tumour growth, a large glioblastoma multiforme was found at autopsy at the site of the increased activity. Radiation leukoencephalopathy was also observed at autopsy. It is concluded that PET studies may offer new information regarding the metabolic effects of anti-tumor therapy, and may demonstrate regrowth of tumor prior to CT.
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PMID:Sequential computerized tomography and positron emission tomography studies in a patient with malignant glioma. 282 89

Over 150 cases of central nervous system tumors have been studied with positron emission tomography using fluorine-18-labeled fluorodeoxyglucose (18FDG) as a tracer. From this material 100 consecutive cases of cerebral glioma have been reviewed and analyzed. The results show a strong correlation of tumor grade with glycolytic rate, with visual "hot spots" present in all high-grade neoplasms and in only four low-grade tumors. The quantitative accuracy is limited by three basic factors. First, the measurement of tissue uptake, as compared with the parent technique, autoradiography, is more difficult because detection must be done outside the body. Effects such as scattered radiation and self-attenuation introduce errors unless properly corrected. A more serious problem when measuring small structures, such as a rim-shaped high-grade glioma, is the limited spatial resolution. The most advanced scanner, the Neuro-PET, has a resolution of 6 to 7 mm. Second, corrections are needed for backflow, including free tracer at the time of the scan that will return to the blood and "trapped" tracer that will backflow because of the presence of phosphatase. These corrections are calculated from the blood activity using nominal rate constants for 18FDG. Our study found no significant alteration in rate constants between normal and tumoral tissue. Finally, a lumped constant is needed to correct for kinetic differences between 18FDG and glucose. If there is a change in the mechanism of either membrane transport or the hexokinase reaction, the lumped constant may change. However, measurements of actual glucose utilization in tissue culture lines from six patients support the 18FDG results.
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PMID:Issues in the in vivo measurement of glucose metabolism of human central nervous system tumors. 633 Dec 82

Iodine-131 3F8, a murine IgG3 monoclonal antibody that targets to GD2-bearing tumors, was administered intravenously to 12 patients with brain tumors. Six patients received 2 mCi (0.74 Bq) of 131I-3F8, five patients 10 mCi (3.7 Bq)/1.73 m2 of 131I-3F8, and one patient 2.6 mCi (0.96 Bq) of 124I-3F8, with no side-effects. Nine of 11 malignant gliomas and the single metastatic melanoma showed antibody localization, with the best tumor delineation on single-photon emission tomography (SPET) following 10 mCi (3.7 Bq)/1.73 m2 dose. No nonspecific uptake in the normal craniospinal axis was detected. There was no difference in the pharmacokinetics of low-dose versus the higher-dose antibody groups; plasma and total-body half-lives were 18 h and 49 h, respectively. Surgical sampling and time-activity curves based on quantitative imaging showed peak uptake in high-grade glioma at 39 h, with a half-life of 62 h. Tumor uptake at time of surgery averaged 3.5 x 10(-3) %ID/g and peak activity by the conjugate view method averaged 9.2 x 10(-3) %ID/g (3.5-17.8). Mean radiation absorption dose was 3.9 rad per mCi injected (range 0.7-9.6) or 10.5 cGy/Bq (range 1.9-26). There was agreement on positive sites when immunoscintigraphy was compared with technetium-99m glucoheptonate/diethylene triamine penta-acetic acid planar imaging, thallium-201 SPET, and fluorine-18 fluorodeoxyglucose positron emission tomography. Taken together, these data suggest that quantitative estimates of antibody targeting to intracranial tumors can be made using the modified conjugate view method.
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PMID:Quantitative studies of monoclonal antibody targeting to disialoganglioside GD2 in human brain tumors. 764 50

Positron emission tomography (PET) with fluorine-18 fluorodeoxyglucose (FDG) was performed in 19 patients with brain metastases from non-central nervous system (CNS) neoplasms and one patient with a primary CNS lymphoma. Various histopathologic types were represented by the primary neoplasms in the patients with metastases. Only 21 of the 31 lesions (68%) were detected with FDG PET as discrete, metabolically active foci (relative to surrounding structures). Six of the nondetected lesions may have been nondiscernible owing to their small size and/or isointensity relative to closely apposed normal gray matter. However, four lesions of at least 1.2 cm in diameter showed frankly decreased FDG accumulation relative to normal brain. These findings suggest that studies of FDG accumulation by a variety of non-CNS neoplasms and their CNS metastases are in order and that extrapolation of the successes of FDG PET in imaging of primary glial tumors to imaging of brain metastases should proceed with caution.
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PMID:Brain metastases from non-central nervous system tumors: evaluation with PET. 841 53

To elucidate the mechanism of large neutral amino acid (LNAA) transport in cerebral gliomas and to evaluate the clinical usefulness of positron emission tomography (PET) with fluorine-18 fluorophenylalanine (18F-Phe), we examined 18 patients with cerebral glioma using dynamic PET and 18F-Phe. By employing two-compartment model analysis, the influx rate K1, the efflux rate k2 and the distribution volume (Vd) of 18F-Phe were estimated in tumour tissue and contralateral normal grey matter. 18F-Phe showed increased accumulation in tumour tissue regardless of the grade of malignancy in all patients. The rate of uptake of 18F-Phe in high-grade glioma was significantly higher than in low-grade glioma (P <0.05). However, it was difficult to evaluate the tumour grade only from the 18F-Phe accumulation in individual cases. Values of K1 and Vd were significantly increased in the tumour tissue. The K1 value of the tumour tissue tended to decrease with increasing LNAA concentration in plasma. Therefore, influx of 18F-Phe into tumour tissue is mainly related to the carrier-mediated active transport. It is concluded that PET with 18F-Phe is of clinical value for tumour detection rather than assessment of tumour malignancy.
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PMID:Quantitative evaluation of neutral amino acid transport in cerebral gliomas using positron emission tomography and fluorine-18 fluorophenylalanine. 875 76

Using single-photon emission tomography (SPET), the radiopharmaceutical l-3-iodine-123-alpha-methyl tyrosine (IMT) has been applied to the imaging of amino acid transport into brain tumours. It was the aim of this study to investigate whether IMT SPET is capable of differentiating between high-grade gliomas, low-grade gliomas and non-neoplastic brain lesions. To this end, IMT uptake was determined in 53 patients using the triple-headed SPET camera MULTISPECT 3. Twenty-eight of these subjects suffered from high-grade gliomas (WHO grade III or IV), 12 from low-grade gliomas (WHO grade II), and 13 from non-neoplastic brain lesions, including lesions after effective therapy of a glioma (five cases), infarctions (four cases), inflammatory lesions (three cases) and traumatic haematoma (one case). IMT uptake was significantly higher in high-grade gliomas than in low-grade gliomas and non-neoplastic lesions. IMT uptake by low-grade gliomas was not significantly different from that by non-neoplastic lesions. Diagnostic sensitivity and specificity were 71% and 83% for differentiating high-grade from low-grade gliomas, 82% and 100% for distinguishing high-grade gliomas from non-neoplastic lesions, and 50% and 100% for discriminating low-grade gliomas from non-neoplastic lesions. Analogously to positron emission tomography with radioactively labelled amino acids and fluorine-18 deoxyglucose, IMT SPET may aid in differentiating high-grade gliomas from histologically benign brain tumours and non-neoplastic brain lesions; it is of only limited value in differentiating between non-neoplastic lesions and histologically benign brain tumours.
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PMID:Uptake of iodine-123-alpha-methyl tyrosine by gliomas and non-neoplastic brain lesions. 878 Nov 39


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