[Show abstract][Hide abstract] ABSTRACT: Comparative genomic hybridization (CGH) is a molecular cytogenetic technique that allows the genome-wide analysis of DNA sequence copy number differences. We applied conventional CGH and the recently developed high-resolution CGH (HR-CGH) to tumour samples from 18 patients with glioblastoma multiforme (GBM) in order to compare the sensitivity of CGH and HR-CGH in the screening of chromosomal abnormalities. The abnormalities were studied in topologically different central and peripheral tumour parts. A total of 78 different changes were observed using CGH (0-16 per tumour, median 3.5) and 154 using HR-CGH (0-21 per tumour, median 6). Using HR-CGH, losses were more frequent than gains. The representation of the most prominent changes revealed by both methods was similar and was comprised of the amplification of 7q12 and 12q13-q15, the gain of 7, 3q and 19, and the loss of 10, 9p, and 13q. However, HR-CGH detected certain other abnormalities (the loss of 6, 14q, 15q and 18q, and the gain of 19), which were rarely revealed by CGH. Using HR-CGH, the numbers and types of chromosomal changes detected in the central and peripheral parts of GBM were almost the same. The loss of chromosomes 10 and 9p and the gain of chromosomes 7 and 19 were the most frequent chromosomal alterations in both tumour parts. Our results from the GBM analysis show that HR-CGH technology can reveal new, recurrent genetic alterations involving the genes known to participate in tumorigenesis and in the progression of several human malignancies, thus allowing for a more accurate genetic characterization of these tumours.
[Show abstract][Hide abstract] ABSTRACT: Glioblastoma multiforme (GBM) is the most common as well as the most aggressive type of primary brain tumor of astrocytic origin in adults. GBM is characterized by a high degree of intratumoral heterogeneity both in histomorphology and genetic changes. Trisomy/polysomy of chromosome 7, monosomy of chromosome 10, EGFR gene amplification and p53 deletion have been described as the typical genetic markers for tumor classification and prediction of possible response to therapy. Our work was based on detection of these four main genetic changes both in central and peripheral parts of the tumors to evaluate possible differences in the topological incidence of these genetic markers. Chromosomal abnormalities in tumor samples from a group of 21 patients surgically treated for GBM were characterized by means of the interphase-fluorescence in situ hybridization (I-FISH) technique using sets of centromere and locus-specific DNA probes. In addition, we performed a detailed analysis of one selected tumor sample using a genomic microarray system (GenoSensor Array 300) to characterize copy number changes of specific sequences and refine results obtained by I-FISH. However, the data show no significant differences in occurrence of the described genetic markers in either part of the tumor.
[Show abstract][Hide abstract] ABSTRACT: Nestin is a protein belonging to class VI of intermediate filaments that is produced in stem/progenitor cells in the mammalian CNS during development and is consecutively replaced by other intermediate filament proteins (neurofilaments, GFAP). Down-regulated nestin may be re-expressed in the adult organism under certain pathological conditions (brain injury, ischemia, inflammation, neoplastic transformation). Our work focused on a detailed study of the nestin cytoskeleton in cell lines derived from glioblastoma multiforme, because re-expression of nestin together with down-regulation of GFAP has been previously reported in this type of brain tumor.
Two cell lines were derived from the tumor tissue of patients treated for glioblastoma multiforme. Nestin and other cytoskeletal proteins were visualized using imunocytochemical methods: indirect immunofluorescence and immunogold-labelling.
Using epifluorescence and confocal microscopy, we described the morphology of nestin-positive intermediate filaments in glioblastoma cells of both primary cultures and the derived cell lines, as well as the reorganization of nestin during mitosis. Our most important result came through transmission electron microscopy and provided clear evidence that nestin is present in the cell nucleus.
Detailed information concerning the pattern of the nestin cytoskeleton in glioblastoma cell lines and especially the demonstration of nestin in the nucleus represent an important background for further studies of nestin re-expression in relationship to tumor malignancy and invasive potential.
[Show abstract][Hide abstract] ABSTRACT: Glioblastoma multiforme (GBM, grade IV astrocytoma) is the most common adult primary brain tumor with high genetic and histomorphological variability. Cytogenetic diagnostic methods represent recently an integral part of glioblastoma diagnostics. Different types of glioblastomas are associated with distinct chromosomal aberrations that may provide useful information with respect to tumor classification, prognosis prediction, and response to therapy. Methods and Results. In this study, we present the molecular cytogenetic results of tumor specimens from 27 patients with glioblastoma multiforme diagnosis. We investigated chromosomal abnormalities in touch preparations from central and peripheral parts of the tumor by interphase-fluorescence in situ hybridization (I-HSH). This method was used to detect the incidence of the most frequent genetic abnormalities such as the polysomy of chromosome 7, monosomy of chromosome 10, the EGFR gene amplification, and p53 deletion. The results of I- FISH analyses showed monosomy 10 in 100% of cases, polysomy 7 (2-5 copies of chromosome 7) in 93% of cases, EGFR gene amplification was present in 26% of tumors and p53 gene deletion in 22% of cases. Conclusions. Our results confirm high frequency of cytogenetic abnormalities involved in the pathogenetic process of GBM which can be used as specific diagnostic and predictive markers.
[Show abstract][Hide abstract] ABSTRACT: The Somatic Mutation and Recombination Test (SMART) in wing cells of Drosophila melanogaster, the Vicia faba cytogenetic tests-Sister Chromatid Exchange (SCE) and Micronucleus Test (MN), and the Müller test for gametic mutations in Arabidopsis thaliana were used for genotoxicity testing of environmental samples of pollutants from the surroundings of LACHEMA chemical factory (Brno, Czech Republic) and DEZA factory in Valasské Mezirící (Moravia, Czech Republic). Tested soil and air samples were taken from the near vicinity of both factories. The surroundings of both sites are heavy loaded by exhalation of chemicals from the factories. Chemical analyses of the 16 Polycyclic Aromatic Hydrocarbons (PAHs) according to the United States Environmental Protection Agency (US EPA) list of priority pollutants and heavy metals were performed in both soil and air samples. The Drosophila wing spot test was positive in 70.6% of the tested samples, the Vicia sister chromatid exchange test in 62.5%, and the Arabidopsis Müller test in 58.9%. The micronucleus Vicia faba test was quite insensitive in tested environmental samples. The concordance between SMART and SCE was 62.5%, between SMART and Müller test 76.5%, and between Müller test and SCE 100%. Total concordance of these three tests was 79.7%. Müller test for gametic mutation in Arabidopsis thaliana and cytogenetic SCE test in Vicia faba seem to be quite sensitive and convenient plant bioassays for assessing the mutagenic potential of environmental agents, when compared to the SMART test in Drosophila melanogaster.
[Show abstract][Hide abstract] ABSTRACT: The induction of sister chromatid exchanges (SCEs) inVicia faba root-tip cells after short-term (2 h) and long-term (24 h) treatments with alkylating agents (N-methyl-N-nitrosourea, ethyl
methanesulphonate) and maleic hydrazide was studied. The primary roots were treated with mutagens before or after 5-bromodeoxyuridine
(BrdU) incorporation into DNA and the influence of mutagen application on SCE induction in the cells with non- and BrdU-substituted
chromosomal DNA. On the contrary, application of maleic hydrazide after the incorporation of BrdU into DNA strongly increased
the rate of SCEs. The lowest limit concentrations of mutagens capable of significantly increasing SCE frequency in the cells
with non-substituted DNA after the long-term treatment were estimated.
No preview · Article · Jan 1995 · Biologia Plantarum