[Preimplantation genetic diagnosis (PGD) in carriers of chromosomal translocations: possibilities and results]. / Moznosti a výsledky preimplantacní genetické diagnostiky (PGD) u páru s chromozomální translokací.

AIM OF THE STUDY: To assess the PGD results in couples with robertsonian and reciprocal translocations. DESIGN: Retrospective study. SETTING: Sanatorium Pronatal, Prague, accredited IVF unit. METHODS: 94 infertile couples with translocation (44 couples with robertsonian and 50 couples with reciprocal translocations) were included in the study. The mean woman's age was not different: 33 +/- 4,4 in robertsonian vers. 33 +/- 3.9 in reciprocal translocations. The performance of FISH probes in specific cases was tested on patient's lymfocytes before the treatment was started. After ovarian stimulation (recombinant FSH or hMG + GnRH agonist, "long" protocol) and transvaginal oocyte pick-up, embryo biopsy of a single cell was performed 72 hours after fertilization. After blastomere fixation, translocated chromosomes + chromosomes 13, 18, 21, X and Y were tested using FISH. The maximum of two embryos euploid for detected chromosomes were transferred, supernumerary euploid embryos were frozen. RESULTS: From the total number of 629 embryos, 126 embryos (21.9%) were detected as normal or with balanced translocation--25.2% (68/270) in couples with robertsonian and 16.4% (59/359) with reciprocal translocation. Embryotransfer was performed in 30 cycles (68.2%) in robertsonian and 27 (54%) in reciprocal translocations. 24 pregnancies were achieved--15 (39% per cycle and 50% per ET) for robertsonian and 9 (19% per cycle and 33% per ET) for reciprocal translocation--this difference was statistically significant (p = 0.033). Only one pregnancy in each group ended as abortion. SUMMARY: IVF is a valuable option for couples with infertility problems and translocation. This technique allows in short-term a conception and delivery of a healthy baby with general better prognosis for couples with robertsonian translocation.

Development of in vivo derived diploid and tetraploid pig embryos in a modified medium NCSU 37.

The aim of this study was to assess development of diploid and tetraploid in vivo derived pig embryos cultured in a modified medium NCSU 37 in an atmosphere with reduced concentration of oxygen. The tetraploid embryos were produced by electrofusion of two-cell embryos that had been cultured in vitro from the one-cell stage before fusion (cultured two-cell embryos) or by fusion of freshly recovered two-cell embryos. Development to blastocyst stage of tetraploid embryos, generated from the cultured two-cell embryos was significantly inferior to the development of control one-cell embryos (29.1 +/- 9.7% versus 66.8 +/- 9.7%; P < 0.05). However, development of tetraploid embryos produced from the freshly recovered two-cell embryos and control two-cell embryos was very similar (89.9 +/- 6.1% versus 81.3 +/- 3.4%). Detection of chromosomes 1 and 10 by in situ hybridization showed that more than 85% of the cultured control embryos were diploid while 15% of the embryos were mosaic. Among the fused embryos 50% were tetraploid, 29% mosaic and 21% diploid. These data indicate that the modified medium NCSU 37 provides optimum environment for pre-implantation development of pig diploid and tetraploid embryos.

[Preimplantation genetic diagnosis (PGD) of chromosomal aberrations using the fluorescence in situ hybridization method (FISH)--introduction to problems, sampling methods and examination techniques]. / Preimplantacní genetická diagnostika (PGD) chromosomálních aberací metodou fluorescencní in situ hybridizace (FISH)--úvod do problematiky, prehled metod pri odberu materiálu a technika vysetrení.

OBJECTIVE: Presentation of preimplantation genetic diagnosis and the set of laboratory processes like aspiration, preparation and evaluation of polar bodies, sperm cells and blastomeres using FISH method (fluorescent in situ hybridization) in ART. DESIGN: Review. SETTING: Sanatorium REPROMEDA, Brno, Veterinary Research Institute, Brno. METHODS: Overview of published data and own clinical experience with the cell aspiration methods, evaluated sample preparation and the proper chromosomes visualisation using FISH method. CONCLUSION: The review brings an overview of conditions and methods including sample obtaining, FISH analysis preparation and implementation, processed during PGD.

Aneuploidy detection in porcine embryos using fluorescence in situ hybridization.

In contrast to human embryos, there are very few studies published on the frequency of chromosomal aneuploidy in farm animals. The objectives of this study were to apply a three-color fluorescent in situ hybridization (FISH) method for evaluating aneuploidy in porcine embryos using chromosome-specific DNA probes, establish baseline frequencies of aneuploidy in embryos and compare the results with our previous findings of aneuploidy in spermatozoa and oocytes. The embryos were collected from superovulated gilts, which were slaughtered 48 h after insemination. FISH was performed using probes specific for the centromeric regions of porcine chromosomes 1, 10 and Y. Altogether 403 blastomeres from 114 porcine embryos were successfully investigated. Diploidy was observed in 101 (88.6%) embryos, triploidy in 2 (1.8%) embryos, mosaicism/mixoploidy in 9 (7.9%) embryos, and trisomy for chromosomes 1 or 10 in 2 (1.8%) embryos. No blastomere showed aneuploidy for chromosome Y. These findings correspond with the frequencies of aneuploidy we have found previously in porcine germ cells.

Frequency of aneuploidy in pig oocytes matured in vitro and of the corresponding first polar bodies detected by fluorescent in situ hybridization.

The objectives of this study were to develop a two-color fluorescent in situ hybridization (FISH) method for evaluating aneuploidy in gilt oocytes using chromosome-specific DNA probes, and to establish baseline frequencies of aneuploidy in pig oocytes matured in vitro. The ovaries were collected from gilts at the local slaughterhouse. Immature oocytes were isolated by slicing the cortex of the ovaries. The oocytes were matured in microplate wells using TCM-199 medium supplemented with 10% estrous cow serum, sodium pyruvate, antibiotics, and gonadotrophins. After 44 h of maturation the oocytes were incubated with hyaluronidase and the cumulus cells were removed by vortexing. Single oocytes were transferred into 1 microL drops of a lysing buffer (0.01 N HCl/0.1% Tween 20) on clean microscopic slides. Two-color FISH was performed using probes specific for Chromosomes 1 and 10. The probe for Chromosome 1 was labeled with Cy3-dUTP and a probe labeled with fluorescein-11-dUTP was used for Chromosome 10. Only oocytes in which a complementary first polar body was found were confirmed as aneuploid. The final assessment of aneuploidy was based on results of 1189 haploid oocytes. Thirty-four (3%) of the examined oocytes were aneuploid. Disomy of Chromosome 1 and Chromosome 10 was found in 12 of 34 and 8 of 34 of the aneuploid oocytes, respectively. Nullisomy of Chromosome 1 and Chromosome 10 was found in 8 of 34 and 6 of 34 of the aneuploid oocytes. No significant differences were found in the frequencies of disomies and nullisomies of oocytes or in the frequencies of aneuploidies of Chromosomes 1 and 10. The frequency of aneuploid oocytes determined by FISH seems to be higher than that determined by conventional methods in other laboratories.

A potential relationship between the 16;20 and 14;20 Robertsonian translocations and low in vitro embryo development.

A possible effect of 16;20 and 14;20 Robertsonian translocations on the development of bovine oocytes matured and fertilized in vitro was assessed on the basis of embryo yield and blastocyst formation. Oocytes fertilized with semen from 2 bulls (A and B), which were heterozygous for these translocations, showed a significantly lower cleavage rate (36.3 +/- 2.25%; 39.8 +/- 3.88%) and percentage of blastocysts (3.7 +/- 1.24%; 3.2 +/- 1.20%) than those fertilized with semen from a bull (C) with a normal karyotype (control, 58.1 +/- 2.14%; 20.1 +/- 1.92%; P < 0.01). There was also a difference in the rate of further blastocyst development between the tested bulls and the control. The rates of expanded blastocysts were 6.6 and 11.1% for Bulls A and B, respectively, and 38.7% for the control bull on Day 7; while on Day 8 these values were 41.7 and 55.5% vs 76.0%. These results demonstrated that in the bulls carrying the 16;20 and 14;20 translocations, in vitro preimplantation embryo development was reduced, probably due to genetically unbalanced spermatozoa.