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)

A 50-year-old male presented with a rare intraparenchymal metastatic tumor spreading through the periventricular tissue. Magnetic resonance (MR) imaging demonstrated the tumor as a heterogeneous low-intensity area on T1-weighted images with enhancement by gadolinium-diethylenetriaminepenta-acetic acid, and as a heterogeneous high- or isointensity area on T2-weighted images. Histological examination of a biopsy sample showed adenocarcinoma. This MR imaging appearance is typical of malignant glioma. The differential diagnosis of tumor in the cerebral parenchyma with ventricular dissemination should include both primary and secondary intracranial malignant tumors. MR imaging is useful in the diagnosis of such tumors, but the final diagnosis should be based on either tissue biopsy or cytological examination of the cerebrospinal fluid.
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PMID:Intraparenchymal metastatic tumor with periventricular dissemination--case report. 904 6

[11C]Acetate, a myocardial PET imaging agent for analysis of oxidative metabolism, has potential use in tumor imaging. Aromatic fatty acids display antitumor effects with phenylacetate currently in clinical trial. Tumor differentiation and cytostasis resulting from phenylacetate treatment may involve the peroxisome proliferator-activated receptor alpha (PPARalpha). To examine whether aromatic fatty acids are potential imaging agents for PPARalpha or tumors in general, [11C]phenylacetic acid (PAA) and [18F]fluorophenyl-acetic acid (FPAA) were synthesized and evaluated in EMT-6 tumor bearing mice and 9L-Glioma tumor bearing rats and compared to [11C]acetate. [11C]Acetate showed better tumor accumulation than PAA or FPAA. The aromatic fatty acids did not directly bind PPARalpha as confirmed by a biodistribution study of PAA in PPARalpha -/- mice.
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PMID:Investigations into tumor accumulation and peroxisome proliferator activated receptor binding by F-18 and C-11 fatty acids. 1182 26

Primary brain tumors (gliomas) often present with peritumoral edema. Their ability to thrive in this osmotically altered environment prompted us to examine volume regulation in human glioma cells, specifically the relative contribution of Cl(-) channels and transporters to this process. After a hyposmotic challenge, cultured astrocytes, D54-MG glioma cells, and glioma cells from human patient biopsies exhibited a regulatory volume decrease (RVD). Although astrocytes were not able to completely reestablish their original prechallenge volumes, glioma cells exhibited complete volume recovery, sometimes recovering to a volume smaller than their original volumes (V(Post-RVD) < V(baseline)). In glioma cells, RVD was largely inhibited by treatment with a combination of Cl(-) channel inhibitors, 5-nitro-2-(3-phenylpropylamino)benzoic acid (NPPB) and Cd(2+) (V(Post-RVD) > 1.4*V(baseline)). Volume regulation was also attenuated to a lesser degree by the addition of R-(+)-[(2-n-butyl-6,7-dichloro-2-cyclopentyl-2,3-dihydro-1-oxo-1H-inden-5-yl)oxy]acetic acid (DIOA), a known K(+)-Cl(-) cotransporter (KCC) inhibitor. To dissect the relative contribution of channels vs. transporters in RVD, we took advantage of the comparatively high temperature dependence of transport processes vs. channel-mediated diffusion. Cooling D54-MG glioma cells to 15 degrees C resulted in a loss of DIOA-sensitive volume regulation. Moreover, at 15 degrees C, the channel blockers NPPB + Cd(2+) completely inhibited RVD and cells behaved like perfect osmometers. The calculated osmolyte flux during RVD under these experimental conditions suggests that the relative contribution of Cl(-) channels vs. transporters to this process is approximately 60-70% and approximately 30-40%, respectively. Finally, we identified several candidate proteins that may be involved in RVD, including the Cl(-) channels ClC-2, ClC-3, ClC-5, ClC-6, and ClC-7 and the transporters KCC1 and KCC3a.
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PMID:Relative contribution of chloride channels and transporters to regulatory volume decrease in human glioma cells. 1565 14

There is considerable chemical and structural similarity between the widely used oncophilic substance pentavalent dimercaptosuccinic acid labeled with (99m)Tc [(99m)Tc-DMSA(V)] and the renal imaging agent trivalent [(99m)Tc-DMSA(III)]. Other renal imaging agents like diethyltriamine penta acetic acid (DTPA) and glucoheptonate labeled with (99m)Tc have been used for imaging brain lesions, mainly for brain tumor imaging. The aim of this study was to evaluate technetium labeled (99m)Tc-DMSA(III) for brain tumor imaging. Single photon emission computed tomography (SPECT) of the brain with (99m)Tc-DMSA(III) was performed in twenty-three patients with brain tumors in recurrence and the results were correlated with contrast enhanced magnetic resonance imaging (MRI) findings. Ten patients had multiform blioblastoma, 7 patients had anaplastic astocystoma, 5 patients low grade glioma and 1 patient menengioma. Our results show that brain SPECT was able to detect 20 of the 21 tumors detected by the contrast enhanced MRI of the brain. The brain scan was false positive in one patient. In two other patients two sites of radiation necrosis showed no tracer concentration. We conclude that (99m)Tc-DMSA(III) concentrates in recurrent brain tumors and can be used for the imaging of these tumors.
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PMID:Imaging of recurrent brain tumors with trivalent (99m)Tc-dimercaptosuccinic acid - initial results. 1686 41

High blood levels of ammonium/ammonia (NH(4)(+)/NH(3)) are associated with severe neurotoxicity as observed in hepatic encephalopathy (HE). Astrocytes are the main targets of ammonium toxicity, while neuronal cells are less vulnerable. In the present study, an astrocytoma cell line 1321N1 and a neuroblastoma glioma hybrid cell line NG108-15 were used as model systems for astrocytes and neuronal cells, respectively. Ammonium salts evoked a transient increase in intracellular calcium concentrations ([Ca(2+)](i)) in astrocytoma (EC(50)=6.38 mM), but not in NG108-15 cells. The ammonium-induced increase in [Ca(2+)](i) was due to an intracellular effect of NH(4)(+)/NH(3) and was independent of extracellular calcium. Acetate completely inhibited the ammonium effect. Ammonium potently reduced calcium signaling by G(q) protein-coupled receptors (H(1) and M3) expressed on the cells. Ammonium (5 mM) also significantly inhibited the proliferation of 1321N1 astrocytoma cells. While mRNA for the mammalian ammonium transporters RhBG and RhCG could not be detected in 1321N1 astrocytoma cells, both transporters were expressed in NG108-15 cells. RhBG and RhBC in brain may promote the excretion of NH(3)/NH(4)(+) from neuronal cells. Cellular uptake of NH(4)(+)/NH(3) was mainly by passive diffusion of NH(3). Human 1321N1 astrocytoma cells appear to be an excellent, easily accessible human model for studying HE, which can substitute animal studies, while NG108-15 cells may be useful for investigating the role of the recently discovered Rhesus family type ammonium transporters in neuronal cells. Our findings may contribute to the understanding of pathologic ammonium effects in different brain cells, and to the treatment of hyperammonemia.
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PMID:Ammonium-induced calcium mobilization in 1321N1 astrocytoma cells. 1806 Dec 26

Proper delineation of gliomas using contrast-enhanced magnetic resonance imaging (CE-MRI) poses a problem in neuro-oncology. The blood brain barrier (BBB) in areas of diffuse-infiltrative growth may be intact, precluding extravasation and subsequent MR-based detection of the contrast agent gadolinium diethylenetriaminepenta-acetic acid (Gd-DTPA). Treatment with antiangiogenic compounds may further complicate tumor detection as such compounds can restore the BBB in angiogenic regions. The increasing number of clinical trials with antiangiogenic compounds for treatment of gliomas calls for the development of alternative imaging modalities. Here we investigated whether CE-MRI using ultrasmall particles of iron oxide (USPIO, Sinerem) as blood pool contrast agent has additional value for detection of glioma in the brain of nude mice. We compared conventional T1-weighted Gd-DTPA-enhanced MRI to T2*-weighted USPIO-enhanced MRI in mice carrying orthotopic U87 glioma, which were either or not treated with the antiangiogenic compound vandetanib (ZD6474, ZACTIMA). In untreated animals, vessel leakage within the tumor and a relatively high tumor blood volume resulted in good MRI visibility with Gd-DTPA- and USPIO-enhanced MRI, respectively. Consistent with previous findings, vandetanib treatment restored the BBB in the tumor vasculature, resulting in loss of tumor detectability in Gd-DTPA MRI. However, due to decreased blood volume, treated tumors could be readily detected in USPIO-enhanced MRI scans. Our findings suggest that Gd-DTPA MRI results in overestimation of the effect of antiangiogenic therapy of glioma and that USPIO-MRI provides an important complementary diagnostic tool to evaluate response to antiangiogenic therapy of these tumors.
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PMID:Magnetic resonance imaging-based detection of glial brain tumors in mice after antiangiogenic treatment. 1808 Oct 12

The tyrosine kinase receptor, c-Met, and its substrate, the hepatocyte growth factor (HGF), are implicated in the malignant progression of glioblastomas. In vivo detection of c-Met expression may be helpful in the diagnosis of malignant tumours. The C6 rat glioma model is a widely used intracranial brain tumour model used to study gliomas experimentally. We used a magnetic resonance imaging (MRI) molecular targeting agent to specifically tag the cell surface receptor, c-Met, with an anti-c-Met antibody (Ab) linked to biotinylated Gd (gadolinium)-DTPA (diethylene triamine penta acetic acid)-albumin in rat gliomas to detect overexpression of this antigen in vivo. The anti-c-Met probe (anti-c-Met-Gd-DTPA-albumin) was administered intravenously, and as determined by an increase in MRI signal intensity and a corresponding decrease in regional T(1) relaxation values, this probe was found to detect increased expression of c-Met protein levels in C6 gliomas. In addition, specificity for the binding of the anti-c-Met contrast agent was determined by using fluorescence microscopic imaging of the biotinylated portion of the targeting agent within neoplastic and 'normal'brain tissues following in vivo administration of the anti-c-Met probe. Controls with no Ab or with a normal rat IgG attached to the contrast agent component indicated no non-specific binding to glioma tissue. This is the first successful visualization of in vivo overexpression of c-Met in gliomas.
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PMID:In vivo detection of c-Met expression in a rat C6 glioma model. 1820 57

Gliomatosis cerebri is a diffuse growth pattern of glioma consisting of exceptionally extensive infiltration of at least three cerebral lobes. We report a case of histologically confirmed glioblastoma multiforme in the cerebellar vermis which occurred 9 years after treatment for gliomatosis cerebri. A 33-year-old woman presented to our department for evaluation of visual disturbance. T2-weighted magnetic resonance (MR) imaging revealed hyperintense lesions in the bilateral frontal and parietal lobes. Histological examination of biopsy specimens from the left frontal lobe lesion demonstrated diffuse infiltration of glial neoplastic cells with preservation of the underlying cytoarchitecture, leading to the diagnosis of gliomatosis cerebri. She received 60 Gy hyperfractionated irradiation to the whole brain, and the lesion responded partially. The patient remained stable for 4 years, but T2-weighted MR imaging 5 years after the initial treatment showed enlargement of the hyperintense area. She received nimustine hydrochloride chemotherapy, and again partial response was observed. However. T1-weighted MR imaging after administration of gadolinium-diethylenetriaminepenta-acetic acid detected enhanced lesions in the cerebellar vermis, cerebellar hemisphere, and left posterior limb of the internal capsule 9 years after the initial treatment, although no abnormal findings were observed on initial and follow-up MR imaging. She underwent subtotal removal of the lesion in the cerebellar vermis. The surgical specimens were characterized by dense proliferation of atypical tumor cells with scattered mitosis and endothelial proliferation. The histological diagnosis was glioblastoma multiforme. The patient received gamma knife irradiation for the remnant lesion in the cerebellar vermis, and the lesions in the cerebellar hemisphere and left posterior limb of the internal capsule, and chemotherapy with temozolomide. However, multiple enhanced lesions were detected in the cerebellar vermis 2 months after the start of the temozolomide chemotherapy, and she died 8 months later. This case suggests that glioblastoma multiforme could develop in the long term after initial treatment for gliomatosis cerebri, and in a location separate from the initial lesion.
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PMID:[Glioblastoma multiforme developing separately from the initial lesion 9 years after successful treatment for gliomatosis cerebri: a case report]. 1870 May 34

Photofrin photodynamic therapy (PDT) caused a dose-dependent decrease of enzymatic cell detachment by trypsin/ethylenediamine tetra-acetic acid (EDTA) in human glioma U251n and U87 cells. This happened coincidently with the increase of intracellular free calcium ([Ca(2+)](i)). Thapsigargin, which increased [Ca(2+)](i), induced further decrease in enzymatic cell detachment and increased cytotoxicity. Opposite effects were observed when 1,2-bis(2-aminophenoxy) ethane-N,N,N',N'-tetra-acetic acid tetrakis, an intracellular Ca(2+) chelator, was used. PDT-induced changes in [Ca(2+)](i) and cell detachment were not blocked by calcium channel antagonists nickel (Ni(2+)) or nimodipine, nor were they altered when cells were irradiated in a buffer free from Ca(2+) and magnesium (Mg(2+)), suggesting that [Ca(2+)](i) is derived from the internal calcium stores. Decreased cell migration was observed after PDT, as assessed by chemotactic and wound-healing assays. Our findings indicated that internal calcium store-derived [Ca(2+)](i) plays an important role in PDT-induced enzymatic cell detachment decrease and cytotoxicity. Cell migration may be affected by these changes.
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PMID:Intracellular free calcium mediates glioma cell detachment and cytotoxicity after photodynamic therapy. 1919 72

The well-vascularized nature of gliomas has generated a lot of interest in antiangiogenic therapies. However, the potential of vascular disrupting agents (VDAs) against gliomas has not been investigated extensively. In this study, we examined the in vivo efficacy of the tumor-VDA 5,6-dimethylxanthenone-4-acetic acid (DMXAA) against gliomas. Contrast-enhanced magnetic resonance imaging (MRI) and diffusion-weighted MRI were used to characterize the vascular and cellular responses of GL261 and U87 gliomas to DMXAA treatment. Therapeutic efficacy was assessed by Kaplan-Meier survival analysis. Before VDA treatment, minimal enhancement was detected within the tumor in both models. Longitudinal relaxation rate (R1=1/T1) maps acquired 24 h after treatment showed marked extravasation and accumulation of the contrast agent in the tumor indicative of treatment-induced vascular disruption. Normalized change in relaxation rate (DeltaR1) values of the tumor showed a significant increase (P<0.01 GL261; P<0.05 U87) after therapy compared with baseline estimates. Mean apparent diffusion coefficient (ADC) values were significantly increased (P=0.015) 72 h after therapy in GL261 but not in U87 gliomas. Vascular disrupting agent therapy resulted in a significant (P<0.01) increase in median survival in both models evaluated. The results highlight the potential of VDAs against gliomas and the utility of MRI in the assessment of glioma response to VDA therapy.
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PMID:MRI-based characterization of vascular disruption by 5,6-dimethylxanthenone-acetic acid in gliomas. 1945 3


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