Update in preimplantation genetic diagnosis. Age, genetics, and infertility

Sex determining of cat embryo and some feline species

Sex identification in mammalian preimplantation embryos is a technique that is used currently for development of the embryo transfer industry for zootechnical animals and is, therefore, a resource for biodiversity preservation. The aim of the present study was to establish a rapid and reliable method for the sexing of preimplantation embryos in domestic cats. Here we describe the use of nested PCR identify Y chromosome-linked markers when starting from small amounts of DNA and test the method for the purpose of sexing different species of wild felids. To evaluate the efficiency of the primers, PCR analysis were performed first in blood samples of sex-known domestic cats. Cat embryos were produced both in vitro and in vivo and the blastocysts were biopsied. A Magnetic Resin System was used to capture a consistent amount of DNA from embryo biopsy and wild felid hairs. The results from nested PCR applied on cat blood that corresponded to the phenotypical sex. Nested PCR was also applied to 37 embryo biopsies and the final result was: 21 males and 16 females. Furthermore, β-actin was amplified in each sample, as a positive control for DNA presence. Subsequently, nested PCR was performed on blood and hair samples from some wild felines and again the genotyping results and phenotype sex corresponded. The data show that this method is a rapid and repeatable option for sex determination in domestic cat embryos and some wild felids and that a small amount of cells is sufficient to obtain a reliable result. This technique, therefore, affords investigators a new approach that they can insert in the safeguard programmes of felida biodiversity.

Bilateral orchiectomy for the surgical treatment of complete androgen insensitivity syndrome: patient outcome after 1 year of follow-up

OBJECTIVE

To describe an operative approach to bilateral orchiectomy for complete androgen insensitivity syndrome (AIS) and to report patient status 1 year after surgery.

MATERIAL AND METHOD

A 19(1/2)-year-old woman with primary amenorrhea, cervical/uterine agenesis, elevated serum testosterone, and 46,XY karyotype underwent characterization of the androgen receptor mutation by polymorphism sequence analysis. Bilateral orchiectomy was performed via a triple-puncture 5-mm laparoscope, and postsurgical hormone replacement followed a daily oral contraceptive model. Psychological counseling was provided to the patient and her family.

RESULTS

Minimally invasive removal of the gonads was accomplished without complication. Microscopic examination of the testes revealed a benign Sertoli cell-only pattern. After 1 year, the patient's level of functioning and psychosexual status were unchanged in comparison with before surgery.

CONCLUSIONS

Patients with complete AIS should undergo postpubertal gonadectomy because of an increased risk for malignant transformation of the testicles, and this can be performed safely via small-caliber laparoscopy. Attention to psychological considerations in such patients is important to maximize long-term success.

Rapid sexing of preimplantation bovine embryo using consecutive and multiplex polymerase chain reaction (PCR) with biopsied single blastomere

The objective of this study was to establish a rapid and reliable PCR method for the sexing of 8- to 16-cell stage bovine embryos. The BOV97M and bovine 1.715 satellite DNA sequences were selected for amplification of male- and bovine-specific DNA, respectively. But the unequal number of copies of these two repetitive sequences required some modification of the multiplex PCR method. In consecutive and multiplex PCR, the first 10 PCR cycles were done with male-specific primer followed by an additional 23 cycles with bovine-specific primer. In this PCR method, the appearance of male- and bovine-specific bands was independent of the DNA concentration. This PCR method was applied successfully using groups of 8, 4, 2, and 1 blastomeres dissociated from the embryos, and the sexing efficiency was 100.0, 96.3, 94.3 and 92.1%, respectively. The coincident rate of sex determination between biopsied single blastomere and matched blastocyst was 90.0%. Therefore the developmental potential from 8- to 16-cell stage embryos to the blastocyst stage was not significantly different (P>0.2) for intact embryo (42.3%) than for demi-embryos (53.8%), suggesting that trauma to the demi-embryo caused by single-blastomere aspiration using a bevelled micropipette was very small. In conclusion, we developed a rapid (within 2 hours) and effective PCR method for the sexing of 8- to 16-cell stage bovine embryos using a single blastomere.