Biomaterial Database

Cryopreservation of gametes and cleavage stage embryos. 1989

E R Siebzehnrübl

Department of Obstetrics and Gynaecology, University of Erlangen-Nürnberg, FRG.

The initial idea by the pioneers of in-vitro fertilization of human eggs on cryopreserving those fertilized oocytes or early embryonic stages was to avoid their replacement into cycles of ovarian hyperstimulation. In this article, a historical review and an assessment of freezing methods and means of cryopreservation is presented. Advantages and disadvantages of freezing early cleavage stages and blastocysts are discussed. Subsequently, ethical arguments are taken into consideration, which under certain circumstances such as legislation in the Federal Republic of Germany, support the procedure of cryopreserving pronuclear oocytes rather than unfertilized eggs or embryonic stages. Finally, there are some most actual calculations reported which reflect attempts to improve the overall success rate of in-vitro fertilization by means of various therapeutic strategies in which cryopreserved oocytes and embryos are essentially involved.

UI	MeSH Term	Description	Entries
D008297	Male		Males
D001757	Blastomeres	Undifferentiated cells resulting from cleavage of a fertilized egg (ZYGOTE). Inside the intact ZONA PELLUCIDA, each cleavage yields two blastomeres of about half size of the parent cell. Up to the 8-cell stage, all of the blastomeres are totipotent. The 16-cell MORULA contains outer cells and inner cells.	Blastocytes,Blastocyte,Blastomere
D002970	Cleavage Stage, Ovum	The earliest developmental stage of a fertilized ovum (ZYGOTE) during which there are several mitotic divisions within the ZONA PELLUCIDA. Each cleavage or segmentation yields two BLASTOMERES of about half size of the parent cell. This cleavage stage generally covers the period up to 16-cell MORULA.	Segmentation Stage, Ovum,Cleavage Stages, Ovum,Ovum Cleavage Stage,Ovum Cleavage Stages,Ovum Segmentation Stage,Ovum Segmentation Stages,Segmentation Stages, Ovum
D005260	Female		Females
D005307	Fertilization in Vitro	An assisted reproductive technique that includes the direct handling and manipulation of oocytes and sperm to achieve fertilization in vitro.	Test-Tube Fertilization,Fertilizations in Vitro,In Vitro Fertilization,Test-Tube Babies,Babies, Test-Tube,Baby, Test-Tube,Fertilization, Test-Tube,Fertilizations, Test-Tube,In Vitro Fertilizations,Test Tube Babies,Test Tube Fertilization,Test-Tube Baby,Test-Tube Fertilizations
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia
D013094	Spermatozoa	Mature male germ cells derived from SPERMATIDS. As spermatids move toward the lumen of the SEMINIFEROUS TUBULES, they undergo extensive structural changes including the loss of cytoplasm, condensation of CHROMATIN into the SPERM HEAD, formation of the ACROSOME cap, the SPERM MIDPIECE and the SPERM TAIL that provides motility.	Sperm,Spermatozoon,X-Bearing Sperm,X-Chromosome-Bearing Sperm,Y-Bearing Sperm,Y-Chromosome-Bearing Sperm,Sperm, X-Bearing,Sperm, X-Chromosome-Bearing,Sperm, Y-Bearing,Sperm, Y-Chromosome-Bearing,Sperms, X-Bearing,Sperms, X-Chromosome-Bearing,Sperms, Y-Bearing,Sperms, Y-Chromosome-Bearing,X Bearing Sperm,X Chromosome Bearing Sperm,X-Bearing Sperms,X-Chromosome-Bearing Sperms,Y Bearing Sperm,Y Chromosome Bearing Sperm,Y-Bearing Sperms,Y-Chromosome-Bearing Sperms
D015053	Zygote	The fertilized OVUM resulting from the fusion of a male and a female gamete.	Fertilized Ovum,Ovum, Fertilized,Fertilized Egg,Egg, Fertilized,Eggs, Fertilized,Fertilized Eggs,Zygotes
D015925	Cryopreservation	Preservation of cells, tissues, organs, or embryos by freezing. In histological preparations, cryopreservation or cryofixation is used to maintain the existing form, structure, and chemical composition of all the constituent elements of the specimens.	Cryofixation,Cryonic Suspension,Cryonic Suspensions,Suspension, Cryonic