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)

To delineate the tumor margins of malignant gliomas laser-induced fluorescence detection technique was applied using 5-aminofluorescein-albumin as the fluorescent dye. The 5-aminofluorescein was linked to serum albumin (= AFlc-SA) as a cumulative protein label using residualizing markers. In a C6-glioma model the biodistribution and pharmacokinetics of the injected dye were investigated by labeling the protein conjugate with 111In-DTPA. Twenty-four hours after intravenous injection of the dye, fluorescence was activated by an argon laser and inspected in the C6-gliomas. Histological examinations were performed to compare the microscopic margins of the fluorescence-stained tumors with hematoxylin/eosin. The tumor uptake 24 h after dye injection was 23-fold higher than in the surrounding brain. Fluorescence inspection under laser activation demonstrated clearly stained and sharply demarcated tumors. The microscopic borders of the tumors corresponded exactly with the fluorescence, also demonstrating intracellular tumor uptake of the dye. In a preliminary study, three patients with malignant gliomas were operated using laser-induced fluorescence detection technique after injection of AFlc-SA. In all patients, the borders of the malignant gliomas were clearly stained by AFlc-SA during surgery. Laser-induced fluorescence imaging using the albumin conjugate AFlc-SA may be a promising method for delineating tumor margins which are hard to detect under the operating microscope alone.
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PMID:Laser-induced fluorescence detection of malignant gliomas using fluorescein-labeled serum albumin: experimental and preliminary clinical results. 1093 21

Intravenous MRI contrast agents are commonly used to improve the detection of intracranial tumors and other central nervous system (CNS) lesions for diagnosis and treatment planning. Two small-molecule, albumin-binding blood pool contrast agents (MP-2269 and MS-325) of potential clinical significance were evaluated at 1.5 Tesla in a mouse glioma model and compared with an extracellular contrast agent (OptiMARK). Tumor image contrast was significantly enhanced and long-lived following administration of 30 micromole/kg of the blood pool agents: specifically, contrast enhancement peaked slowly at 25-30 min following administration, remained constant for >3 hr, and returned to baseline within 20 hr. Comparable but "transient" enhancement was achieved using 100 micromole/kg OptiMARK: specifically, contrast enhancement peaked rapidly at 2-5 min following administration and then declined over 40 min. The blood pool contrast agents demonstrated an approximately threefold increased dose-effectiveness and a lengthened window of tumor contrast enhancement in comparison to commonly available extracellular contrast agents. This demonstrates the potential of alternative contrast-enhanced (CE) MRI examination protocols for tumor detection.
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PMID:Albumin-binding MR blood pool agents as MRI contrast agents in an intracranial mouse glioma model. 1259 65

1. The blood-brain barrier (BBB) represents the major impediment to successful delivery of therapeutic agents to target tissue within the central nervous system. Intracarotid alkylglycerols have been shown to increase the transfer of chemotherapeutics across the BBB. 2. We investigated the spatial distribution of intracarotid fluorescein sodium and intravenous lissamine-rhodamine B200 (RB 200)-albumin in the brain of normal and C6 glioma-bearing rats after intracarotid co-administration of 1-O-pentylglycerol (200 mm). To elucidate the mechanisms involved in the alkylglycerol-mediated BBB opening, intraluminal accumulation of fluorescein isothiocyanate (FITC)-dextran 40,000 was studied in freshly isolated rat brain capillaries using confocal microscopy during incubation with different alkylglycerols. Furthermore, 1-O-pentylglycerol-induced increase in delivery of methotrexate (MTX) to the brain was evaluated in nude mice. 3. Microscopic evaluation showed a marked 1-O-pentylglycerol-induced extravasation of fluorescein and RB 200-albumin in the ipsilateral normal brain. In glioma-bearing rats, increased tissue fluorescence was found in both tumor tissue and brain surrounding tumor. Confocal microscopy revealed a time- and concentration-dependent accumulation of FITC-dextran 40,000 within the lumina of isolated rat brain capillaries during incubation with 1-O-pentylglycerol and 2-O-hexyldiglycerol, indicating enhanced paracellular transfer via tight junctions. Intracarotid co-administration of MTX and 1-O-pentylglycerol (200 mm) in nude mice resulted in a significant increase in MTX concentrations in the ipsilateral brain as compared to controls without 1-O-pentylglycerol (P<0.005). 4. In conclusion, 1-O-pentylglycerol increases delivery of small and large compounds to normal brain and brain tumors and this effect is mediated at least in part by enhanced permeability of tight junctions.
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PMID:Alkylglycerol opening of the blood-brain barrier to small and large fluorescence markers in normal and C6 glioma-bearing rats and isolated rat brain capillaries. 1459 99

Zinc uptake is critical for cell proliferation. On the basis of the evidence that brain tumors are positively-imaged with 65Zn, cellular zinc uptake was studied under growth arrest and apoptosis to understand the relationship between cellular viability and zinc uptake. When NIH3T3 cells were cultured in albumin-coated dishes under the presence of serum, the viability of the cells detached from the extracellular matrix, which was determined with fluoresceine diacetate, was almost the same as the control cells cultured in untreated dishes. Both the uptake of 14C-thymidine and 65Zn by the cells was significantly suppressed by detachment from the extracellular matrix, suggesting that cellular zinc uptake is suppressed by growth arrest. When apoptosis was induced in the cells detached from the extracellular matrix under serum-free condition, 65Zn uptake by the cells led to apoptosis which was significantly higher than that by the control cells. 65Zn uptake by C6 glioma cells, which were irradiated with gamma-ray, was also higher than that by control (unirradiated) C6 glioma cells. The present study demonstrates that zinc uptake is involved not only in the process of cell proliferation, but also in the process of apoptosis.
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PMID:Change of zinc uptake under growth arrest and apoptosis. 1573 24

Traditional glioma chemotherapy with those second-line drugs such as anthracyclines usually failed because they are inaccessible to blood-brain barrier (BBB) in tumor. In our study, we incorporated aclarubicin (ACL) into cationic albumin-conjugated pegylated nanoparticle (CBSA-NP-ACL) to determine its therapeutic potential of rats with intracranially implanted C6 glioma cells. When labeled with fluorescent probe, 6-coumarin, CBSA-NP was shown to accumulate much more in tumor mass than nanoparticle without conjugated CBSA (NP) 1 hr post intravenous injection, as well as better retention after 24 hr. Tumor drug concentration of CBSA-NP-ACL displayed 2.6- and 3.3-fold higher than that of NP-ACL and ACL solution 1 hr post injection, while 2.7 and 6.6-fold higher after 24 hr, respectively. Moreover, using tumor microdialysis sampling, AUC(0-24 hr) of free drug amount in tumor interstitium delivered by CBSA-NP-ACL was about 2.0- and 2.7-fold higher than that of NP-ACL and ACL solutions, respectively. When the tumor rat model was subjected to 4 cycles of 2 mg/kg of ACL in different formulations, a significant increase of median survival time was found in the group of CBSA-NP-ACL compared with that of saline control animals, animals treated with NP-ACL and ACL solution. By terminal deoxynucleotidyl transferase-mediated dUTP nick-end-labeling, CBSA-NP-ACL can extensively make the tumor cell apoptosis. Histochemical evaluation by periodic acid Shiff staining and biochemical analysis depicted that the incorporation of ACL into CBSA-NP reduced its toxicity to liver, kidney and heart. Besides, CBSA-NP-ACL was not shown to open tight junction evaluated by BBB coculture. It was concluded that CBSA-NP-ACL could have a therapeutic potential for treatment of glioma.
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PMID:Aclarubicin-loaded cationic albumin-conjugated pegylated nanoparticle for glioma chemotherapy in rats. 1706 46

Patients with malignant gliomas have a poor prognosis because these tumors do not respond well to conventional treatments. Studies of glioma xenografts suggest that they may be amenable to gene therapy with cytotoxic genes, such as the proapoptotic Apo2 ligand/tumor necrosis factor-related apoptosis-inducing ligand (Apo2L/TRAIL). Gene therapy of gliomas ideally employs i.v. given vectors, thus excluding viral vectors as they cannot cross the brain microvascular endothelium or blood-brain barrier. Recently, we reported the synthesis of cationic albumin-conjugated pegylated nanoparticles (CBSA-NP) and showed their accumulation in mouse brain cells upon i.v. administration. In this study, plasmid pORF-hTRAIL (pDNA) was incorporated into CBSA-NP, and the resulting CBSA-NP-hTRAIL was evaluated as a nonviral vector for gene therapy of gliomas. Thirty minutes after transfection of C6 glioma cells, CBSA-NP-hTRAIL was internalized and mostly located in the cytoplasm, whereas NP-hTRAIL was entrapped in the endolysosomal compartment. At 6 and 48 hours after transfection, respectively, released pDNA was present in the nuclei and induced apoptosis. At 30 minutes after i.v. administration of CBSA-NP-hTRAIL to BALB/c mice bearing i.c. C6 gliomas, CBSA-NP-hTRAIL colocalized with glycoproteins in brain and tumor microvasculature and, via absorptive-mediated transcytosis, accumulated in tumor cells. At 24 and 48 hours after i.v. administration of CBSA-NP-hTRAIL, respectively, hTRAIL mRNA and protein were detected in normal brain and tumors. Furthermore, repeated i.v. injections of CBSA-NP-hTRAIL induced apoptosis in vivo and significantly delayed tumor growth. In summary, this study indicates that CBSA-NP-hTRAIL is a promising candidate for noninvasive gene therapy of malignant glioma.
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PMID:Cationic albumin-conjugated pegylated nanoparticles allow gene delivery into brain tumors via intravenous administration. 1717 85

Metastatic carcinoma, which is a common malignant tumor seen in the central nervous system is often difficult to distinguish from glioblastoma multiforme. In general, neoplastic cells maintain fidelity in the expression of parent cell intermediate filament and immunohistochemistry remains the mainstay in diagnosis. A panel consisting of GFAP (usually positive for astrocytic tumors) and cytokeratin (usually positive for metastatic carcinomas) is most commonly used for this purpose. However, co-expression of two or more classes of intermediate filament proteins by neoplasms is a widespread phenomenon and there are reports of glial neoplasms expressing keratin markers. Our aims and objectives were to analyse the expression of both cytokeratin and GFAP in different glial tumors and metastatic carcinomas. Cases were collected for a period of two years. All the cases were diagnosed as primary or metastatic intracranial tumors. Formalin-fixed paraffin-embedded thin sections were taken on egg-albumin coated slides and immunostaining with GFAP and polyclonal cytokeratin was done. Forty-five tumors were analysed, including 35 glial neoplasms and 10 metastatic carcinomas of which 7 of the 32 astrocytic neoplasms (22%) showed focal immunoreactivity with pancytokeratin. All of the glial tumors but none of the metastatic carcinomas were positive with GFAP. So our conclusion was that co-expression of GFAP and CK is a fairly common phenomenon, especially in case of undifferentiated and high grade gliomas and this must be kept in mind while differentiating these cases from metastatic carcinoma, as CK positivity does not rule out the diagnosis of a glial neoplasm. Further studies with an expanded panel of CK is most useful for this.
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PMID:Expression of cytokeratins in gliomas. 1788 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

In animal models, methionine (MET) restriction in association with chloroethylnitrosoureas led to a substantial improvement. On this basis, we initiated a Phase I clinical trial of dietary MET restriction in association with chloroethylnitrosourea (cystemustine) treatment for patients with recurrent glioma or metastatic melanoma. Our purpose was 1) to determine the optimal MET-free diet duration for a maximum depletion of plasma MET and 2) to evaluate the feasibility of this association. A total of 10 patients received 4 cycles of 2 wk of an association of a MET-free diet of 1, 2, 3, or 4 consecutive days and cystemustine (60 mg/m(2)). For each cycle, plasma MET concentrations, nutritional status (weight, albumin, prealbumin) and toxicity were measured. Conversely, fed-state concentrations of plasma MET (12 AM) were reduced by dietary MET restriction, with an optimal depletion of 41% at the 1st day of MET-free diet without effect of the extending MET-free diet period. Indeed, we demonstrated the feasibility, that is, good diet acceptability and good tolerance (nutritional status and toxicity), of the association of a MET-free diet and cystemustine treatment. Based on these results, a Phase II clinical trial has been initiated to test the activity of the association of a 1-day MET-free diet with cystemustine treatment.
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PMID:Optimal methionine-free diet duration for nitrourea treatment: a Phase I clinical trial. 1844 32

Increased iNOS expression is often found in brain tumors, such as gliomas. The goal of this study was to develop and assess a novel molecular MRI (mMRI) probe for in vivo detection of iNOS in rodent models for gliomas (intracerebral implantation of rat C6 or RG2 cells or ethyl nitrosourea-induced glioma). The probe we used incorporated a Gd-DTPA (gadolinium(III) complex of diethylenetriamine-N,N,N',N'',N''-pentaacetate) backbone with albumin and biotin moieties and covalent binding of an anti-iNOS antibody (Ab) to albumin (anti-iNOS probe). We used mMRI with the anti-iNOS probe to detect in vivo iNOS levels in gliomas. Nonimmune normal rat IgG coupled to albumin-Gd-DTPA-biotin was used as a control nonspecific contrast agent. By targeting the biotin component of the anti-iNOS probe with streptavidin Cy3, fluorescence imaging confirmed the specificity of the probe for iNOS in glioma tissue. iNOS levels in glioma tumors were also confirmed via Western blots and immunohistochemistry. The presence of plasma membrane-associated iNOS in glioma cells was established by transmission electron microscopy and gold-labeled anti-iNOS Ab. The more aggressive RG2 glioma was not found to have higher levels of iNOS compared to C6. Differences in glioma vascularization and blood-brain barrier permeability between the C6 and the RG2 gliomas are discussed. In vivo assessment of iNOS levels associated with tumor development is quite feasible in heterogeneous tissues with mMRI.
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PMID:In vivo detection of inducible nitric oxide synthase in rodent gliomas. 2003 58


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