Use of fluorescence in situ hybridization to measure chromosome aberrations as a predictor of radiosensitivity in human tumour cells.

Fluorescence in situ hybridization (FISH) is a potential assay for determining cellular radiosensitivity based on the detection of chromosome damage. This approach was chosen because of its relative simplicity and short assay time. Two radiosensitive and two radioresistant human tumour cell lines were used.

Automatic fluorescence metaphase finder speeds translocation scoring in FISH painted chromosomes.

A fluorescence metaphase finder was constructed with commercially available hardware and a standard Unix workstation. Its accuracy was measured in terms of the number of false positive and false negative detected metaphases on a variety of different slide preparations. The metaphase finder was used in a translocation scoring experiment in which metaphase preparations of human peripheral blood lymphocytes were hybridized with whole chromosome probes to chromosomes #1, #2, and #4.

Duplication 9q34-->qter identified by chromosome painting.

We have studied an infant with multiple anomalies and a 46,XY,12p+ karyotype. Parental chromosomes were normal, and it was not possible to determine the identity of the extra material on chromosome 12 cytogenetically. Chromosome painting with probes from a chromosome 9 library identified this material as coming from chromosome 9, and cytogenetics established the duplication as 9q34-->qter.

Translocations between two specific human chromosomes detected by three-color "chromosome painting".

Translocations between two specific chromosomes are important markers for many human malignancies. Previously, the detection of translocations involving random breakpoints between two specific chromosomes could only be accomplished by banding techniques, which are severely labor intensive and require highly trained technicians. The three-color chromosome painting approach described in this paper was developed in our laboratory to detect translocations between two specific human chromosomes rapidly and accurately, while simultaneously revealing the nonhybridized chromosomes.

Rapid translocation frequency analysis in humans decades after exposure to ionizing radiation.

This paper presents an analysis of the utility of fluorescence in situ hybridization (FISH) with whole-chromosome probes for measurement of the genomic frequency of translocations found in the peripheral blood of individuals exposed to ionizing radiation. First, we derive the equation: Fp = 2.05fp(1-fp)FG, relating the translocation frequency, Fp, measured using FISH to the genomic translocation frequency, FG, where fp is the fraction of the genome covered by the composite probe.

The persistence of chromosome translocations in a radiation worker accidentally exposed to tritium.

The chromosome translocation frequency in lymphocytes of an individual accidentally exposed to tritium six years previously was measured using chromosome painting. Comparisons with results from cytogenetic studies shortly after the accident indicate that the translocation frequency has remained unaltered in this individual for six years.

Two-color hybridization with high complexity chromosome-specific probes and a degenerate alpha satellite probe DNA allows unambiguous discrimination between symmetrical and asymmetrical translocations.

This report describes a fluorescence in situ hybridization approach to chromosome staining that facilitates detection of structural aberrations and allows discrimination between dicentric chromosomes and symmetrically translocated chromosomes. In this approach, selected whole chromosomes are stained in one color by hybridization with composite probes whose elements have DNA sequence homology along the length of the target chromosomes. In addition, all chromosomes are counterstained with a DNA specific dye so that structural aberrations between target and non-target chromosomes are clearly visible.