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Full Karyotype Analysis for Increasing Pregnancy Rates per IVF Cycle

Reference number IB-1992

APPLICATIONS OF TECHNOLOGY:

     
   
  An image of a metaphase spread showing one of the Berkeley Lab probe sets detecting six human chromosomes by Spectral Imaging. Each DNA-probe within a set is labeled with a unique fluorochrome. An in-house SKY (Spectral Karyotyping) system is employed for assessing the FISH signals. The system identifies the chromosome-specific signals and applies pseudocolors. This probe set and three additional sets will be used in subsequent fluorescent in situ hybridizations to evaluate all human chromosomes in metaphases and most importantly in interphases.  
     
  • Screening all 24 chromosomes for numeric chromosome abnormalities during Preimplantation Genetic Diagnosis
  • Diagnosing disease states requiring cytogenetic analysis
  • Monitoring the effects of accidental or occupational exposure to environmental hazards

ADVANTAGES:

  • Allows full karyotype analysis of cells in interphase
  • Highly adaptable and flexible assay design
  • Works with a variety of cell types

EXPECTED OUTCOMES:

  • Fewer spontaneous abortions
  • Fewer transfers required to achieve pregnancy, thereby reducing costs and inefficiencies


ABSTRACT:

Ulli Weier of Berkeley Lab and colleagues have developed a novel and flexible FISH protocol for use with fluorescence microscopy or Spectral Imaging to significantly reduce the overall cost per pregnancy and increase pregnancy rates following in vitro fertilization.  While current FISH protocols characterize a subset of chromosomes, the Berkeley Lab method enables full karyotype analysis of a cell in interphase. 

The Berkeley Lab protocols are the first to use up to eight chromosome specific DNA probes simultaneously to complete a full karyotype analysis in repeated rounds of hybridization in time for implantation.  This test can identify all numeric chromosome abnormalities, which will reduce the chances of spontaneous abortion from nonmosaic embryos.  When performed on polar bodies, the test should also increase the chances of fertilization. At present, the use of eight probes simultaneously requires Spectral Imaging while the use of six probes simultaneously is compatible with conventional fluorescence microscopy or Spectral Imaging. The scoring system can be tailored to individual needs.

While conventional chromosome characterization methods can be applied only to blastomeres and first polar bodies, the Berkeley Lab test can be applied to nuclei from second polar bodies, spermatocytes, and somatic and tumor cells, as well.

     
   
  FISH results from normal male lymphocytes hybridized with two sets of probes and analyzed with a Spectral Imaging system. (A) The red, green or blue (RGB) color image of one interphase nuclei hybridized with the set 1 probes shows a total of 12 signals (two copies of chromosomes 13, 14, 16, 20, 21, and 22). (B) The red, green or blue (RGB) color image of one interphase nuclei hybridized with the second set probes shows a total of 10 signals (one copy of chromosome X, one copy of chromosome Y, and two copies of chromosomes 15, 17, 18, and 19).  
     

STATUS:

FOR MORE INFORMATION SEE:

Weier, H.-U.G., Weier, J.F., Oter R.M., Zheng, X., Colls, P., Nureddin,A., Pham, C.D., Chu, L.W., Racowsky, C., Munné, S., “Fluorescence in situ hybridization (FISH) and spectral imaging (SIm) analysis of human oocytes and first polar bodies,” J. Histochem. Cytochem., 2005, 53:269-272.

REFERENCE NUMBER: IB-1992

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Last updated: 09/17/2009