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

Plectin is a high molecular weight protein originally identified and characterized as a major cytoskeletal component of the C6 rat glioma cell. Here we demonstrate by immunoblotting of crude intermediate filament (IF) protein preparations that plectin is a cytoskeleton-associated component of the rat spinal cord. We then used avidin-biotin peroxidase immunocytochemistry and indirect immunofluorescence to localize plectin within the adult rat central nervous system (CNS) and examine its distribution with respect to IF proteins. Plectin immunoreactivity is localized to all ependymal cells including the choroidal epithelial cells and tanycytes, Bergmann glial processes, radially oriented glial cells in the spinal cord, astrocytes in white matter, a subset of astrocytes in gray matter, a subset of motoneurons in the brainstem and spinal cord, and certain endothelial cells. Colocalization studies with neural IF proteins show that plectin has a unique distribution pattern which most closely resembles, but is distinct from, that of vimentin. The few plectin positive neurons invariably also contain the neurofilament triplet proteins and peripherin, so that the ability of plectin to bind to the triplet proteins in vitro may reflect an in vivo interaction. The predominance of plectin at the inner ventricular boundaries of the nervous system as well as at the blood-brain barrier is in line with the pattern of plectin expression in other tissues and suggests a general role for plectin in the maintenance of such junctional regions.
 ...
PMID:Distribution of plectin, an intermediate filament-associated protein, in the adult rat central nervous system. 802 73

It has been reported that endothelium in malignant glioma stains with a commercial antibody raised against the receptor for epidermal growth factor (EGFr) on A431 cells (clone 29.1). In this report, this antibody was used to study the immunohistochemical expression of EGFr in benign and malignant ovarian, mid-gut carcinoid, and thyroid neoplasms using the avidin-biotin-peroxidase complex technique. Eighteen of the 37 ovarian neoplasms, 4 of the 10 thyroid neoplasms, and 14 of 28 mid-gut carcinoid tumors expressed strong and distinct endothelial staining, whereas staining results of the remaining tumors were negative. The endothelial nature of the staining was verified by staining serial sections with Ulex europaeus agglutinin-I. The staining was independent of that obtained with an antibody raised against a synthetic peptide consisting of residues 985 to 996 from the cytoplasmic domain of EGFr (clone F4). All positive staining occurred in patients determined to be of blood groups A or AB, whereas samples from patients with blood groups B or O were negative. Immunoabsorption of the antibody with centrifuged erythrocytes from a blood group A donor, but not from a blood group B donor, abolished the positive staining. The data indicate that positive staining of tumor endothelium with this antibody is due to cross-reactivity with blood group A antigen. The results obtained challenge the validity of previously performed immunohistochemical studies in which monoclonal antibodies raised against the EGFr of A431 cells have been used, and in which the epitope for the monoclonal antibody has not been determined.
 ...
PMID:Immunohistochemical identification of receptors for epidermal growth factor in tumor endothelium may be affected by cross-reactivity to blood group A antigen. 842 12

The cell surface sugar determinants (CSSD) were examined in C6 glioma cells in cultures at different conditions of growth by peroxidase conjugates of the lectins: peanut agglutinin (PNA), Ricinus communis agglutinin (RCA), Helix pomatia agglutinin (HPA), wheat germ agglutinin (WGA), lentil agglutinin (LCA), laburnum bork agglutinin (LABA), and lotus agglutinin (TPA). It was found that the cells bound more intensively WGA, LCA, and RCA compared to PNA, HPA; the weakest staining was provided by LABA and TPA. Binding intensity for PNA significantly increased after pretreatment of the cells with neuraminidase. This indicates that a part of the beta-D-galactose residues on the surface membrane of C6 glioma cells is covered by sialic acid. The process of sialization was increased during the culturing of C6 glioma cells. Addition of cis-DDP or dBcAMP to cultures growing in medium with 10% of CS increased the number of Gal residues which are not covered by sialic acid. The expression of beta-D-galactose (Gal), N-acetyl-D-galactosamine (NAcDGal), and fucose (Fuc) residues appeared to be most responsive to changes in growth conditions and degree of cell differentiation. The expressions of N-acetyl-D-glucosamine (NAcDGlc) and mannose (Man) residues were high and seems did not depend on changing of the conditions of culturing. In C6 glioma cells cultures in which the rate of cell division, formation of the cell processes, and adhesiveness of the cells to the substratum were reduced by growing cells in MEM+, expression of beta-Gal, NAcDGal, and Fuc was considerably reduced. The decrease of expression of beta-Gal, NAcDGal, and Fuc on the surface of cell membrane was more pronounced in MEM+ with 1% of CS than in MEM+ with 10% of CS. In DbcAMP and cis-DDP treated cultures, grown in medium with 1% serum, in which cell division was inhibited without obvious changes in cell adhesiveness to the substratum, binding of PNA and HPA was increased due to higher expression of beta-Gal and NAcDGal. From these observations it was concluded that the pattern of expression of sugar residues on the cell surface varies according to the biological state of the cells and are easily affected by tissue culture conditions.
 ...
PMID:Growth related changes in sugar determinants on the surface of C6 glioma cells in culture: a cytochemical lectin-binding study. 856 19

There has been increasing interest in the possible use of boronophenylalanine as a capture agent for boron neutron capture therapy of brain tumors. The purpose of the present study was to determine whether the uptake of boronophenylalanine in F98 glioma-bearing rats could be enhanced by means of intracarotid (i.c.) injection with or without blood-brain barrier disruption (BBB-D). Glioma cells (10(5)) were stereotactically implanted into the right cerebral hemisphere of Fischer rats, and 12 days later, BBB-D was performed by infusing 25% mannitol (1.373 mOsmol/ml) into the right carotid artery and then immediately injecting L-boronophenylalanine (300 mg/kg of body weight) intracarotidly. The animals were killed 0.5, 1, 2.5, and 4 hours later, and the brains were removed for boron determination by direct current plasma atomic emission spectroscopy. BBB-D was assessed by the intravenous injection of Evans blue or horseradish peroxidase, and the barrier-disrupted hemispheres and tumors showed intense staining with each. The mean tumor boron concentration after i.c. injection and BBB-D was 34.8 +/- 6.8 micrograms/g at 2.5 hours compared with 20.3 +/- 6.2 micrograms/g after i.c. injection without BBB-D and 10.7 +/- 0.7 micrograms/g after intravenous injection. No significant differences in boron concentration in muscle, skin, and eye were observed among the different groups. Boron concentrations in the ipsilateral, disrupted hemisphere increased transiently but rapidly returned to background levels by 2.5 hours after BBB-D. The tumor:brain and tumor:blood ratios were 5.2 and 5.6, respectively, compared to 3.2 and 2.1 for intravenous injection groups at 2.5 hours. The present study is the first to show that BBB-D combined with i.c. injection can enhance the tumor uptake of boron compounds for boron neutron capture therapy.
 ...
PMID:Enhanced delivery of boronophenylalanine for neutron capture therapy by means of intracarotid injection and blood-brain barrier disruption. 872 25

Cell culture models have been widely used for screening of neurotoxicants and represent a viable alternative to direct in vivo experiments. We have developed a dynamic in vitro blood-brain barrier model designed to allow for extensive toxicological, pharmacological and physiological testing. Induction of blood-brain barrier properties in a tri-dimensional hollow fiber culturing apparatus was investigated by co-culturing a bovine aortic endothelial cell line (or rat brain endothelial cells) with rat brain astrocytes (or C6 rat glioma cells) under pulsatile flow conditions to mimic intraluminal blood flow. Cell growth was monitored over time by measuring glucose consumption and lactate production: these experiments confirmed that the hollow fiber cell culturing systems can maintain viable cells in culture for extended (> 1 month) periods of time. Cells were visually inspected after culturing and dissociation from the hollow fiber cartridge and identified as endothelial (by fluorescent Dil-Ac-LDL uptake) or glial (by GFAP immunoreactivity). Blood-brain barrier properties were tested by intraluminal injection of horse-radish peroxidase (HRP, mol. weight 44,000), glucose (m.w. 180) or potassium. Either procedure demonstrated that aortic cells co-cultured with astrocytes (or C6 cells) developed a selective barrier with an estimated electrical resistance of 2,900 omega/cm2. The electrophysiological and morphological properties of BAEC were also affected by the co-culturing process, suggesting that astrocytes induced CNS properties in these cells. These results demonstrate that the hollow fiber cell co-culturing system may be used as a dynamic model of the mammalian blood-brain barrier.
 ...
PMID:A dynamic model of the blood-brain barrier "in vitro". 885 43

We have established an enzyme immunoassay for phosphoneuroprotein 14 (PNP 14) which is mainly localized in the cytoplasmic matrix in presynaptic axon terminals and which is phosphorylated in vivo, as well as in vitro. Fab' prepared from rabbit IgG antibodies against bovine PNP 14 was conjugated with maleimide-horseradish peroxidase. The enzyme-conjugated Fab' was used as a second antibody in a sandwich enzyme immunoassay. This assay was able accurately to quantify 0.5-100 ng of rat PNP 14, as well as bovine PNP 14, and it was used for the determination of concentrations of PNP 14 in various rat tissues, neuroblastoma cells, and brains of other vertebrates. The concentrations of PNP 14 in the rat cerebrum, cerebellum, and testis were 1.1, 1.0, and 0.28 micrograms/mg of protein, respectively, and those in other tissues examined were less than 0.1 microgram/mg of protein. PNP 14 was also found in cultured cells, such as rat pheochromocytoma PC12 cells, NG108-15 cells, which are a hybrid between a mouse neuroblastoma and a rat glioma, mouse neuroblastoma Neuro-2a cells, and human neuroblastoma IMR32 cells. Furthermore, PNP 14-specific immunoreactivity was evaluated in the brains of various vertebrates, such as fish, frog, snake and chicken by immunoblot and enzyme immunoassay. The results revealed the immunoreactivity in the brains of all vertebrates examined and the levels were determined to be 0.6-2.1 micrograms bovine PNP 14 equivalents per mg of protein, suggesting that PNP 14 might be an essential component of the central nervous systems of vertebrates.
 ...
PMID:Distribution of phosphoneuroprotein 14 (PNP 14) in vertebrates: its levels as determined by enzyme immunoassay. 900 21

Hepatocyte growth factor/scatter factor (HGF/SF), which has various physiological functions, and its receptor c-Met, the human c-met proto-oncogene product, are thought to be determinant in the pathological processes of various malignancies. To investigate the possible role of HGF/SF in the progression of development of astrocytic tumors, we examined the expression of c-Met in these tumors. Immunohistochemistry using the streptavidin-biotin peroxidase complex method and immunofluorescence double staining with anti-c-Met polyclonal and anti-glial fibrillary acidic protein monoclonal antibodies were performed. Positive c-Met expression was detected in 31 of the 42 astrocytic tumors and some of the control cases analyzed. c-Met-positive cells showed morphological characteristics of astrocytes. Especially in the cases of high-grade tumors, c-Met positivity was abundant in cells in both vascular-rich and peripheral regions of the tumors but not in the cells with distinctly malignant features. Immunofluorescence double staining revealed that the c-Met-positive cells were in part of astrocytic origin. We suggest that c-Met-positive cells are affected by some factors in the lesions where the pathological processes are in a state of development. Our studies indicated that c-Met expression might take part in glioma invasion but not in the development of malignancy.
 ...
PMID:Immunohistochemical examination of c-Met protein expression in astrocytic tumors. 956 11

Many inherited neurological diseases and cancers could potentially benefit from efficient targeted gene delivery to neurons of the central nervous system. The nontoxic fragment C (HC) of tetanus toxin retains the specific nerve cell binding and transport properties of tetanus holotoxin. The HC fragment has previously been used to promote the uptake of attached proteins such as horseradish peroxidase, beta-galactosidase and superoxide dismutase into neuronal cells in vitro and in vivo. We report the use of purified recombinant HC fragment produced in yeast and covalently bound to polylysine [poly(K)] to enable binding of DNA. We demonstrate that when used to transfect cells, this construct results in nonviral gene delivery and marker gene expression in vitro in N18 RE 105 cells (a neuroblastoma x glioma mouse/rat hybrid cell line) and F98 (a glioma cell line). Transfection was dependent on HC and was neuronal cell type specific. HC may prove a useful targeting ligand for future neuronal gene therapy.
 ...
PMID:Non-viral neuronal gene delivery mediated by the HC fragment of tetanus toxin. 1009 62

The simultaneous detection of nitric oxide and glutamate using an array of individually addressable electrodes, in which the individual electrodes in the array were suitably modified with a highly sensitive nitric oxide sensing chemistry or a glutamate oxidase/redox hydrogel-based glutamate biosensor is presented. In a sequence of modification steps one of the electrodes was covered first with a positively charged Ni porphyrin entrapped into a negatively charged electrodeposition paint followed by the manual modification of the second working electrode by a bienzyme sensor architecture based on crosslinked redox hydrogels with entrapped peroxidase and glutamate oxidase. Adherently growing C6-glioma cells were grown on membrane inserts and placed in close distance to the modified sensor surfaces. The current responses recorded at each electrode after stimulation of glutamate and NO release by means of K+ and bradykinin clearly demonstrate the ability of the individual electrode in the array to detect the analyte towards which its sensitivity and selectivity was targeted without interference from the neighbouring electrode or other analytes present in the test mixture.
 ...
PMID:Simultaneous detection of the release of glutamate and nitric oxide from adherently growing cells using an array of glutamate and nitric oxide selective electrodes. 1562 9

Aims-To compare immunostaining between the original Ki67 monoclonal antibody and a new polyclonal Ki67 antibody on frozen and paraffin wax sections of human glioblastomas.Methods-Frozen sections and formalin fixed, paraffin wax embedded sections of the same tumour specimens were included in the study (10 cases). Half of the paraffin wax sections were pretreated in a microwave oven. Standard immunohistochemical techniques were used (avidinbiotin peroxidase complex). Five high power fields were examined using an eye-piece graticule, and 500 to 2000 tumour cells were counted. The labelling index was defined as the percentage of positive tumour cells.Results-The Ki67 monoclonal antibody displayed positive immunostaining in all frozen sections (median labelling index 5.9, range 2.6-11.4) whereas only four paraffin wax sections stained positively and only after pretreatment in a microwave oven. The polyclonal Ki67 antibody elicited positive staining in both frozen sections (median labelling index 13.7, range 6.7-21.5) and in paraffin wax sections (median labelling index 12.0, range 2.2-22.7) but only after pretreatment in a microwave oven.Conclusion-The Ki67 monoclonal antibody is not recommended for use on paraffin wax sections of glioma tissues whereas the new polyclonal Ki67 antibody provides satisfactory immunostaining on both frozen and paraffin wax sections.
 ...
PMID:Comparison of different Ki67 antibodies in human glioblastomas. 1669 4


<< Previous 1 2 3 4 5 6 Next >>