title: A preliminary concept, deduced from cytogenetic analyses, for explaining different types of multipronuclear oocytes obtained after intracytoplasmic sperm injection.
abstract: Oocytes with three or more pronuclei and one or two polar bodies arising after intracytoplasmic sperm injection were analyzed cytogenetically, and the data were used to develop a general model explaining the possible origin of the abnormal pronuclear stages. The mechanisms, either separately or in variable combinations, that induce the appearance of additional pronuclei are: 1) nonextrusion of the second polar body; 2) incomplete chromatid segregation into the extruded second polar body; and 3) dispersal of the oocyte chromatids in the presence of the second polar body formation.
authors.affiliation: Department of Gynecology and Obstetrics, University of Ulm, Ulm, Germany. bernd.rosenbusch@uniklinik-ulm.de
authors.forename: Bernd E
authors.initials: BE
authors.lastname: Rosenbusch
mesh_terms: D000782:Aneuploidy; D002467:Cell Nucleus / Q000502:physiology; D048750:Cell Nucleus Division / Q000502:physiology; D002478:Cells, Cultured; D020090:Chromosome Segregation / Q000502:physiology; D002970:Cleavage Stage, Ovum / Q000145:classification / Q000378:metabolism / Q000502:physiology; D003210:Concept Formation / Q000502:physiology; D020732:Cytogenetic Analysis / Q000379:methods*; D005260:Female; D005306:Fertilization / Q000235:genetics; D006801:Humans; D008297:Male; D009865:Oocytes / Q000166:cytology / Q000378:metabolism / Q000502:physiology; D010865:Pilot Projects; D012189:Retrospective Studies; D020554:Sperm Injections, Intracytoplasmic