Sunday, October 23, 2011

Cytogenetic analysis by chromosome painting. (a series 2 of x)


This is the second in a series on the chromosome painting which is a test that is used to determine  genetic damage.  See the prior post to understand why we are discussing this topic.
Essentially, there is a question about long term systemic effects  of chromosome aberrations in bone-marrow cells adjacent to the prosthesis at revision surgery.  This test is a means to identify those aberrations.  I will have more details on this in the coming weeks but it is my understanding that changes in these chromosomes may not be seen for 10-20 years.
I don't think there have been enough studies to substantiate much but there are two studies that have shown significantly higher rate of chromosomal aberration in local bone-marrow cells adjacent to the hip.
Cytometry. 1994 Mar 15;18(1):2-10.


Department of Pathology, University of Cambridge, United Kingdom.


Chromosome painting is a term used to describe the direct visualisation using in situ hybridisation of specific chromosomes in metaphase spreads and in interphase nuclei. Chromosome painting, coupled with fluorescence in situ hybridisation (FISH), is now used routinely to enhance the identification of chromosomal rearrangements, the assignment of breakpoints, and the determination of the origin of extra chromosomal material. Amplification of small numbers of flow-sorted chromosomes by the polymerase chain reaction allows labelled chromosome paints to be generated in a matter of days. These technologies have enabled the development of reverse chromosome painting, in which the paint is produced from sorted aberrant chromosomes and hybridised back onto normal metaphase spreads to identify directly the composition of the aberrant chromosome. Reverse chromosome painting is able to identify not only the chromosomal origin of marker chromosomes but also the regions and breakpoints involved. In some cases, such as interstitial translocations and complex marker chromosomes, the combination of conventional (forward) chromosome painting and reverse chromosome painting combine to provide a definitive analysis of the rearrangement. With the availability of chromosome paints and painting kits from a variety of commercial sources, multicolour chromosome painting has now become a routine method of analysis in the clinical cytogenetic laboratory.

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