230 research outputs found
Localization of viral transforming sequences within marker chromosomes associated with tumor formation and progression in a murine fibrosarcoma
No full textThe low-metastatic RSV-transformed fibrosarcoma line B77-3T3 and its metastatic variant AA12, selected in vitro, have been analysed by blot and in situ hybridization with v-src and murine c-myc specific probes in order to detect molecular rearrangements underlying the transition from the low-metastatic to the high-metastatic phenotype. Previous cytogenetic analysis had evidenced that a marker chromosome of the parental tumor line (chromosome A) is replaced in the metastatic counterpart by a new marker chromosome (chromosome B), possibly arisen by duplication of a chromosome A segment, included between two C-positive regions (L. Doneda et al., 1985). In situ hybridization on chromosome spreads of the two related lines with a (3)H-labelled v-src probe showed that src sequences are located within the marker chromosomes A and B, and the percentage of grains over the AA12 marker chromosome is always double that found on the B77-3T3 marker. These signals were considered to identify v-src sequences as they were found to be slightly amplified in the metastatic variant DNA by blot hybridization with the v-src probe. As regards the intrachromosomal location of the signals, most grains were clustered near the heterochromatic bands, suggesting a possible role for heterochromatic sites in tumor formation and evolution. No involvement of the A and B marker chromosomes was shown by in situ hybridization experiments with a c-myc probe. However the dosage of c-myc sequences was also found to be slightly increased in the metastatic variant DNA
Loss of Y chromosome with retention of Y heterochromatin in a marker chromosome from a human melanoma
No full textA single copy of a der15 chromosome (m3) characterized by a C- and distamycin A-Dapi-positive region was observed in the -Y hyperploid karyotype of a primary human melanoma (Me 1402). The heterochromatic region was located pericentromerically, adjacent at one end to the NOR region of chromosome 15, and at the other to an unclassifiable chromosomal piece. We established that the C-positive block in the marker chromosome originated from Y heterochromatin by high-stringency in situ hybridization with a DNA probe for the 2.1 Hae III Y-specific repeat. Loss of the Y chromosome in tumors has been considered to be a secondary event associated with malignant evolution. It is significant that Me 1402 cells, which are highly malignant, lack the Y chromosome, but retain its heterochromatic portion in the rearranged m3 chromosome
Three-way and two-way rearrangements involving chromosomes 10, 2, 5 and 5, 2 in two marker chromosomes of a human melanoma cell line
No full textTwo marker chromosomes (mar1 and mar2), provided with two closely spaced heterochromatic bands, were observed in the 14932 cell line established from a human metastatic melanoma. Fluorescence in situ hybridization (FISH) with the alphoid sequence p82H common to all human centromeres showed strong signals over the double C-bands of mar1 and mar2. These were recognized by a chromosome 2-specific alphoid probe, although chromosome in situ suppression (CISS) hybridization with a chromosome 2 library failed to reveal any painting along mar1 and mar2. The centromere of mar1 was identified by a chromosome 10-specific alphoid sequence and the marker chromosome was decorated from pter to a region proximal to the interpolated C-band by a chromosome 10 library. The centromere of mar2 could not be recognized by any chromosome-specific alphoid probe, but the whole mar2 was decorated by a chromosome 5 library. This library also painted the distal q arm of mar1, which was not painted by the chromosome 10 library, as well as a small band proximal to the double C-band. Identification of the two marker chromosomes reveals their common origin and indicates a role for chromosomes 2, 5 and 10 in the genesis and/or progression of the 14932 melanoma. Alteration to the chromosome-specific alphoid sequence in the centromere of mar2 provides evidence for rearrangement of constitutive heterochromatin alphoid sequences in human tumours
EARLY AND DELAYED REPRODUCTIVE DEATH IN HUMAN CELLS EXPOSED TO HIGH ENERGY IRON ION BEAMS
No full textThe aim of this research was to determine the biological effectiveness for early and delayed effects of high energy, high linear energy transfer (LET) charged particles. Survival and delayed reproductive death were measured in AG1522 human fibroblast cells exposed to Fe-ion beams of energies between 0.2 and 1 GeV/n, 0.97 GeV/n Ti-ion and 0.49 GcV/n Si-ion beams. The cells were irradiated at the HIMAC accelerator in Chiba, Japan (0.2 and 0.5 GeV/n Fe and 0.49 GeV/n Si) and at the NASA Space Radiation Laboratory in Brookhaven, USA (1 GeV/n Fe and 0.97 GeV/n Ti ions). The dose-effect curves were measured in the dose range between 0.25 and 2 Gy. For comparison cells were exposed to Co-60 gamma rays. Analysis of the dose-effect curves show that all the heavy ion beams induce inactivation and delayed reproductive death more effectively than 60 Co rays. The only exception is the 0.2 GeV/n Fe-ion beam at low doses. The progeny of the irradiated cells show delayed damage in the form of reproductive death with all the heavy ion beams with the 1 GeV/n Fe-ion beam being the most effective. The relative biological effectiveness at low doses of the iron beams is highest for LET values between 140 and 200 keV/mu m with values of 1.6 and 3 for early and delayed reproductive death, respectively. Analysis of the fluence-effect curves shows that the cross-sections for early and delayed inactivation increase with increasing LET up to 442 keV/mu m. (c) 2005 COSPAR. Published by Elsevier Ltd. All rights reserved
Interphase fish analysis of cytogenetic abnormalities in B-CLL : a study of younger adults patients
No full textRapid construction of competitive templates for quantitative PCR of reverse-transcribed mRNAs
No full textA novel approach of competitive PCR for quantifying mRNAs is described where competitors are constructed by deleting an internal sequence from target reverse transcribed mRNAs. The two sets of product generated (control,and target) are easily discriminated by size and quantified for the sequence of interest and a housekeeping gene, beta-actin used as internal mRNA control
Are cytogenetic aberrations relevant in younger adults with B-cell chronic lymphocytic leucemia? A study of 50 patients
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