Search results for "chromosome aberration"
showing 10 items of 160 documents
Primary mouse fibroblasts deficient for c-Fos, p53 or for both proteins are hypersensitive to UV light and alkylating agent-induced chromosomal break…
2000
The important regulatory proteins, c-Fos and p53 are induced by exposure of cells to a variety of DNA damaging agents. To investigate their role in cellular defense against genotoxic compounds, we comparatively analysed chromosomal aberrations and apoptosis induced by ultraviolet (UV-C) light and the potent alkylating agent methyl methanesulfonate (MMS) in primary diploid mouse fibroblasts knockout for either c-Fos or p53, or double knockout for both genes. We show that c-Fos and p53 deficient fibroblasts are more sensitive than the corresponding wild-type cells as to the induction of chromosomal aberrations and apoptosis. Double knockout fibroblasts lacking both c-Fos and p53 are viable an…
Early induction of genetic instability and apoptosis by arsenic in cultured Chinese hamster cells
2002
In order to assess at what time from the beginning of exposure inorganic arsenic can give rise to genetic instability and trigger apoptosis, V79-C13 Chinese hamster cells were treated with 10 microM sodium arsenite for 24 h. Under these conditions, cell survival was >70% and cells showed neither an increase in chromosome aberration frequency nor a delay in cell cycle progression. Investigations, which were carried out every 6 h during the treatment, revealed an early appearance of genetically unstable cells, namely micronucleated, multinucleated and mononucleated 'giant' cells, as well as apoptotic cells. Indirect immunostaining using anti-beta-tubulin antibody showed severe alterations in …
Arsenic-induced DNA hypomethylation affects chromosomal instability in mammalian cells
2004
Early genetic instability induced in dividing V79-Cl3 Chinese hamster cells by inorganic arsenic, as demonstrated in our previous investigation, was evidenced by aneuploidy and nuclear abnormalities, but not by chromosomal rearrangements. Here we report the results of cytogenetic and morphological analyses performed on the progeny of cells dividing at the end of sodium arsenite treatment after they had been expanded through 120 generations (ASO cells) and then cloned. The acquired genetic instability persisted and was increased by highly unstable chromosomal rearrangements, namely dicentric chromosomes and telomeric associations, which were not seen following acute exposure. A peculiar find…
Complex rearrangement of chromosomes 6 and 11 as the sole anomaly in atypical teratoid/rhabdoid tumors of the central nervous system.
2000
Atypical teratoid/rhabdoid tumor of the central nervous system is a rare childhood tumor with a distinct histologic appearance and an aggressive clinical course. Few tumors have been analyzed cytogenetically. The only consistent chromosomal abnormality identified in some of these tumors has been monosomy or deletions of chromosome 22; in others, a normal chromosome 22 was present. The authors report an atypical teratoid/rhabdoid neoplasm of the central nervous system with a novel complex rearrangement affecting chromosomes 6 and 11 as the sole anomaly. The involvement of region 11p15 could be important in the pathogenesis of this entity.
Chimeric amplicons containing the c-myc gene in HL60 cells
1998
The major amplicon present in HL60 cells is chimeric in nature being composed of 70 kb of DNA sequence derived from the MYC locus linked to 80 kb of novel DNA sequence derived from a non contiguous region located telomeric to the c-myc gene at 8q24 (Feo et al., 1996). Here we show by fluorescence in situ hybridization (FISH) that these coamplified sequences, MCR (Myc Coamplified Region), are derived from a locus located 3-4 Mb telomeric to the c-myc gene in the q24.2-24.3 region of chromosome 8. Genomic cloning and Southern blot analysis indicate the arrangement of chimeric amplicons are in tandem arrays. Analysis of the DNA sequences at the juncture of the MYC locus and the MCR suggest tha…
Genomic Abnormalities Acquired in the Blastic Transformation of Splenic Marginal Zone B-cell Lymphoma
2003
Among 20 cases of typical splenic marginal zone lymphoma (SMZL), two cases had blastic transformation. The genetic mechanisms underlying the morphologic transformation were investigated by comparing genetic changes in initial and blastic phases. A complex karyotype including trisomy of 3q and genomic gain of 17q22-q24 was seen in both cases at diagnosis. However, the extra copy of 3q was lost during the transformation process in both tumors. Additionally, the Karpas 1718 cell line, which was derived from a patient with transformed SMZL and carried a trisomy of 3q, also evidenced the spontaneous loss of the extra 3q during the culturing process. Other acquired abnormalities observed exclusiv…
Cytogenetic analysis of epithelial renal-cell tumors: Relationship with a new histopathological classification
1993
Renal-cell carcinomas (RCC) are clinically, histologically and cytogenetically very heterogeneous. The present histological WHO classification shows no clear correlation between histologic subtypes and specific chromosomal abnormalities. In 1986, a new classification was proposed by Thoenes and Storkel based on the cell type from which the tumor arises. They distinguish S cell types: clear-cell, chromophilic, chromophobic, ductus Bellini and oncocytic. Results of 105 primary tumors show that, in this new classification, there is a correlation between different subtypes of renal-cell tumor and specific chromosomal abnormalities at a microscopic and/or molecular level. The clear-cell compact …
Cytogenetic findings in malignant mixed mesodermal tumors of the uterus.
1997
Abstract Cytogenetic analyses of four malignant mixed mesodermal tumors (MMMT) of the uterus are reported, of which one was of the homologous type and three of the heterologous type. Karyotypic analyses were obtained in two cases from original tumors and in two cases from tumors xenotransplanted into nude mice. The karyotype of the homologous MMMT was normal in three different passages of a nude mice xenograft line established from the primary tumor. The heterologous tumors showed normal karyotype in one case and hyperdiploid and near triploid range with extensive numerical and structural rearrangements in two cases. Deletion of chromosome 1 at p32, and deletion of chromosome 11 at q13 were…
The Proton-Boron Reaction Increases the Radiobiological Effectiveness of Clinical Low- and High-Energy Proton Beams: Novel Experimental Evidence and …
2021
Protontherapy is a rapidly expanding radiotherapy modality where accelerated proton beams are used to precisely deliver the dose to the tumor target but is generally considered ineffective against radioresistant tumors. Proton-Boron Capture Therapy (PBCT) is a novel approach aimed at enhancing proton biological effectiveness. PBCT exploits a nuclear fusion reaction between low-energy protons and 11B atoms, i.e. p+11B→ 3α (p-B), which is supposed to produce highly-DNA damaging α-particles exclusively across the tumor-conformed Spread-Out Bragg Peak (SOBP), without harming healthy tissues in the beam entrance channel. To confirm previous work on PBCT, here we report new in-vitro data obtained…
Molecular cytogenetics of childhood hematological malignancies
1998
Cytogenetic and molecular analyses are essential for the classification of childhood hematologic malignancies. Nearly all children with leukemia should have an adequate cytogenetic analysis which in 80-90% is expected to show clonal chromosomal abnormalities. Moreover, with the availability of appropriate gene probes and sophisticated molecular techniques, genetic rearrangements become detectable in the majority of leukemia patients. Genetic abnormalities often associate with particular clinical-biological characteristics of the disease. In ALL, for example, genetic alterations together with distinct immunologic and clinical features, define various subgroups. In AML, unique cytogenetic rea…