Factors defining developmental competence of bovine oocytes collected for in vitro embryo production†.

Despite the currently relatively low effectiveness of producing bovine embryos in vitro, there is a growing interest in applying this laboratory method in the field of reproduction. Many aspects of the procedure need to be improved. One of the main problems is the inferior developmental competence of in vitro matured oocytes that are collected using the ovum pick-up method.

The many problems of somatic cell nuclear transfer in reproductive cloning of mammals.

In 1996, when Dolly the sheep was born, a new, utopian era was expected to begin. Science fiction and popular culture instantly threatened the public with shortly upcoming human clones, portraying it as a very easy and instant procedure. Practice has proven otherwise; it exposed how little is known about the early development of mammals and epigenetic reprogramming.

Signaling mechanisms and their regulation during in vivo or in vitro maturation of mammalian oocytes.

In vitro fertilization (IVF) is currently one of the most effective methods of infertility treatment. An alternative to commonly used ovarian hyperstimulation can become extracorporeal maturation of oocytes (in vitro maturation; IVM). Fertilization and normal development of the embryo depends on the cytoplasmic, nuclear and genomic maturity of the oocyte.

[Children born from frozen embryos stored for 10 years -- analysis of 5 cases].

Faced with a scientific and legal debate on human embryo cryopreservation in Poland we show 5 documented clinical cases of successful thawing and transfer of embryos cryopreserved for a long period of time (8-11 years), resulting in successful delivery by the biological or the recipient mother. Cases described include patients with different infertility diagnoses, subjected to different hormonal stimulation treatments. Different oocyte fertilization methods were performed, and the obtained embryos were frozen after 2, 3 or 4 days of in vitro culture using methods employing various cryoprotective agents and freezing curves.

Comparison of traditional and modified (VitMaster) methods of rabbit embryo vitrification.

In spite of their cryobiological efficacy, minimum-volume vitrification methods suffer from the risk of microbiological contamination and are technically and/or manually demanding. In this study, the effects of a traditional, slightly modified vitrification method and vitrification using supercooled liquid nitrogen (VitMaster) applied for rabbit morula-stage embryos were compared. Embryos were equilibrated in a solution containing 1,2-propanediol (2.

Melatonin effect on bovine embryo development in vitro in relation to oxygen concentration.

Melatonin promotes mouse embryo development in vitro. An effect of melatonin on bovine embryo development is described here. Slaughterhouse derived oocytes were subjected to standard in vitro maturation and fertilization procedures.

Banking of embryos of mutated, paralytic tremor rabbit by means of vitrification.

Cryopreservation enables banking of embryos for future use in medicine and in animal breeding. It also enables protection of germ plasm of endangered species and unique strains or lanes of laboratory animals. This paper describes an example of employing a vitrification method for banking of embryos of a unique lane of rabbit.