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Molecular cytogenetic analysis of human blastocysts andcytotrophoblasts by multi-color FISH and Spectra Imaging analyses

Description: Numerical chromosome aberrations in gametes typically lead to failed fertilization, spontaneous abortion or a chromosomally abnormal fetus. By means of preimplantation genetic diagnosis (PGD), we now can screen human embryos in vitro for aneuploidy before transferring the embryos to the uterus. PGD allows us to select unaffected embryos for transfer and increases the implantation rate in in vitro fertilization programs. Molecular cytogenetic analyses using multi-color fluorescence in situ hybridization (FISH) of blastomeres have become the major tool for preimplantation genetic screening of aneuploidy. However, current FISH technology can test for only a small number of chromosome abnormalities and hitherto failed to increase the pregnancy rates as expected. We are in the process of developing technologies to score all 24 chromosomes in single cells within a 3 day time limit, which we believe is vital to the clinical setting. Also, human placental cytotrophoblasts (CTBs) at the fetal-maternal interface acquire aneuploidies as they differentiate to an invasive phenotype. About 20-50% of invasive CTB cells from uncomplicated pregnancies were found aneuploidy, suggesting that the acquisition of aneuploidy is an important component of normal placentation, perhaps limiting the proliferative and invasive potential of CTBs. Since most invasive CTBs are interphase cells and possess extreme heterogeneity, we applied multi-color FISH and repeated hybridizations to investigate individual CTBs. In summary, this study demonstrates the strength of Spectral Imaging analysis and repeated hybridizations, which provides a basis for full karyotype analysis of single interphase cells.
Date: February 8, 2006
Creator: Weier, Jingly F.; Ferlatte, Christy; Baumgartner, Adolf; Jung,Christine J.; Nguyen, Ha-Nam; Chu, Lisa W. et al.
Partner: UNT Libraries Government Documents Department

Test for detection of clustering over time. [Statistical study of spontaneous abortions in NYC]

Description: The use of the scan statistic in testing for clustering in time is discussed with particular reference to a reported clustering of trisomies in spontaneous abortions in New York City (spontaneous abortions have been used on occasion to monitor environmental health effects). The scan statistic is the maximum number of observed cases in an interval of preselected length, as the interval is allowed to scan, or slide along, the time frame of interest. A table of the lower tail of the distribution of this statistic is given.
Date: March 1, 1979
Creator: Wallenstein, S
Partner: UNT Libraries Government Documents Department