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Obstetric & Gynaecology

 

 




Preimplantation Genetic Diagnosis 

   

  • First Unaffected Pregnancy Using Preimplantation Genetic Diagnosis for Sickle Cell Anemia.

    Xu K, Shi ZM, Veeck LL, et al (Cornell Univ., New York; Wayne State Univ., Detroit)

    JAMA 281:1701-1706, 1999

        


    Using FSH and HCG to stimulate multiple ovulation, the authors employed IVF and biopsies 2.7 to 3 days after fertilization. Embryos were then transferred to the uterus on day 4 after fertilization. In the first trial, 1 of 4 embryos proved to be genetically normal but failed implantation. In a second trial, 3 of 7 embroyos, either normal (AA) or showing sickle cell trait (AS), were inserted and resulted in 2 AA normal females. In one of the successful transplants, 2 of 7 embryonic cells were removed for biopsy but after 24 hours, the 5 embryonic cells in the morula had increased to 7 in number and thereafter subsequently developed normally.

        


    This experience helps confirm that much of what is known about PGD in animal species is valid in the human. In particular, the ability to remove nearly 30% of the embryonic cells of an early human embryo without interference with implantation and development is of special importance.

        

  • Prenatal Diagnosis with use of Fetal Cells Isolated from Maternal Blood : Five color fluorescent in Situ Hybridization Analysis on Flowsorted Cells for Chromoscomes X, Y, 13, 18 and 21.

    Bischoff FZ, Lewis DE, Nguyen DD, et al (Bayor College of Medicine, Houston; Univ of Tennesee, Memphis). Am J Obstet Gynecol 179:203-209, 1998

         


    Current prenatal cytogenetic diagnostic methods are invasive and carry a small risk to the fetus. It is known that fetal cells exist in the maternal circulation, albeit at very low levels (1 fetal cell in 1 x 104 to 1 x 107 nucleated maternal cells), and can be detected. A 1 step hybridization reaction for 5 color fluorescent in situ hybridization for simultaneous detection of chromosomes, X, Y, 13, 18 & 21 on flow sorted nuclei from maternal blood samples was described.

        


    Conclusion : The 5 color fluorescent in situ hybridization technique allowed accurate and simultaneous analysis of chromosomes X, Y, 13, 18 & 21 in 97.2% of enriched nuclei isolated from maternal blood samples by flow cytometry. Although this procedure is currently costly, it is hoped that cost will decrease as the procedure is automated. This method has promise for noninvasive prenatal screening.

        


    To separate fetal cells present in concentrations less than 1 in a 100,000 in maternal blood with sufficient cell preservation to allow reactivity in recombinant DNA technology is a wonderful accomplishment.

        

      



 

 

Speciality Spotlight

 

 

Preimplantation Genetic Diagnosis 
   

  • First Unaffected Pregnancy Using Preimplantation Genetic Diagnosis for Sickle Cell Anemia.
    Xu K, Shi ZM, Veeck LL, et al (Cornell Univ., New York; Wayne State Univ., Detroit)
    JAMA 281:1701-1706, 1999
        
    Using FSH and HCG to stimulate multiple ovulation, the authors employed IVF and biopsies 2.7 to 3 days after fertilization. Embryos were then transferred to the uterus on day 4 after fertilization. In the first trial, 1 of 4 embryos proved to be genetically normal but failed implantation. In a second trial, 3 of 7 embroyos, either normal (AA) or showing sickle cell trait (AS), were inserted and resulted in 2 AA normal females. In one of the successful transplants, 2 of 7 embryonic cells were removed for biopsy but after 24 hours, the 5 embryonic cells in the morula had increased to 7 in number and thereafter subsequently developed normally.
        
    This experience helps confirm that much of what is known about PGD in animal species is valid in the human. In particular, the ability to remove nearly 30% of the embryonic cells of an early human embryo without interference with implantation and development is of special importance.
        

  • Prenatal Diagnosis with use of Fetal Cells Isolated from Maternal Blood : Five color fluorescent in Situ Hybridization Analysis on Flowsorted Cells for Chromoscomes X, Y, 13, 18 and 21.
    Bischoff FZ, Lewis DE, Nguyen DD, et al (Bayor College of Medicine, Houston; Univ of Tennesee, Memphis). Am J Obstet Gynecol 179:203-209, 1998
         
    Current prenatal cytogenetic diagnostic methods are invasive and carry a small risk to the fetus. It is known that fetal cells exist in the maternal circulation, albeit at very low levels (1 fetal cell in 1 x 104 to 1 x 107 nucleated maternal cells), and can be detected. A 1 step hybridization reaction for 5 color fluorescent in situ hybridization for simultaneous detection of chromosomes, X, Y, 13, 18 & 21 on flow sorted nuclei from maternal blood samples was described.
        
    Conclusion : The 5 color fluorescent in situ hybridization technique allowed accurate and simultaneous analysis of chromosomes X, Y, 13, 18 & 21 in 97.2% of enriched nuclei isolated from maternal blood samples by flow cytometry. Although this procedure is currently costly, it is hoped that cost will decrease as the procedure is automated. This method has promise for noninvasive prenatal screening.
        
    To separate fetal cells present in concentrations less than 1 in a 100,000 in maternal blood with sufficient cell preservation to allow reactivity in recombinant DNA technology is a wonderful accomplishment.
        

      

 

By |2022-07-20T16:43:03+00:00July 20, 2022|Uncategorized|Comments Off on Preimplantation Genetic Diagnosis

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