Birth after double cryopreservation of human oocytes at metaphase II and pronuclear stages.

Objective: To document the possibility to double-cryopreserve human metaphase II and pronuclear oocytes.

Design: Case report.

Setting: University-based IVF center.

Cryopreservation in assisted reproductive technology: new trends.

During the last few years, cryopreservation has become a relevant addition to therapeutic concepts in reproductive medicine. New data and publications have made it difficult to maintain an overview of all of the new developments and their results. The focus of interest more recently, especially with the cryopreservation of human oocytes and human ovarian tissue, has been vitrification as an interesting alternative to slow freezing methods.

Cryoprotectant-free cryopreservation of human spermatozoa by vitrification and freezing in vapor: effect on motility, DNA integrity, and fertilization ability.

Human spermatozoa can be successfully cryopreserved avoiding the use of cryoprotectants through vitrification at very high cooling rates (up to 7.2 x 10(5) degrees C/min). This is achieved by directly plunging a copper cryoloop loaded with a sperm suspension into liquid nitrogen.

In-vitro maturation of germinal-vesicle oocytes and cryopreservation in metaphase I/II: a possible additional option to preserve fertility during ovarian tissue cryopreservation.

This study describes the possibility of combining two options in order to preserve female fertility: cryopreservation of human ovarian tissue and in-vitro matured germinal vesicle (GV) oocytes retrieved during tissue dissection. In contrast to ovarian tissue cryopreservation, the cryostorage of in-vitro matured unfertilized metaphaseI/II oocytes could be a more realistic option. This concept of preserving fertility before chemotherapy and/or radiotherapy without a long time delay could be an additional reason for favouring ovarian tissue cryopreservation.

Effect of cryoprotectants on the ultrastructure of cooled human pronuclear oocytes.

Ultrastructural changes in human pronuclear oocytes were evaluated after cooling in the presence or absence of cryoprotectant.

Developmental rate and ultrastructure of vitrified human pronuclear oocytes after step-wise versus direct rehydration.

Background: This study compared the viability of human pronuclear oocytes subjected to vitrification followed by post-thaw step-wise removal of cryoprotectants versus direct rehydration, in terms of their subsequent in vitro survival and ultrastructural features.

Methods: A total of 115 three-pronuclei stage oocytes were cryopreserved in super-open-pulled straws by vitrification in 40% ethylene glycol + 0.75 mol/l sucrose for either 1 min or 10 s at 38 degrees C, followed by direct plunging into liquid nitrogen.

Effect of different vitrification protocols for human ovarian tissue on reactive oxygen species and apoptosis.

The aim of the present study was to evaluate the effect of different vitrification protocols on reactive oxygen species (ROS) and apoptosis in human ovarian tissue. Human ovarian tissue pieces were exposed to different vitrification solutions. The intracellular redox state level was measured using the fluorescent dye dichlorodihydrofluorescein diacetate.

Modified vitrification of human pronuclear oocytes: efficacy and effect on ultrastructure.

The efficacy of cryopreservation by direct plunging into liquid nitrogen (vitrification) of human pronuclear oocytes using open pulled straws with a super-finely pulled tip, as well as the ultrastructural changes caused by cooling and vitrification, were evaluated. Clinical and electron microscopic studies of cooled and vitrified oocytes were performed. Oocytes were cooled to 4 degrees C in the presence and absence of cryoprotectants, vitrified, warmed, cultured and transferred.

Double vitrification of rat embryos at different developmental stages using an identical protocol.

The aim of the present investigation was to test the effectiveness of a method of vitrifying rat embryos at different stages of development (from early morula to expanding blastocyst) in a double vitrification procedure. Wistar rat embryos were vitrified and warmed in super-fine open-pulled straws (SOPS). Before being plunged into liquid nitrogen, the embryos were exposed to 40% ethylene glycol+0.

Vitrification of mammalian spermatozoa in the absence of cryoprotectants: from past practical difficulties to present success.

The use of cryoprotective agents for the conventional cryopreservation of human spermatozoa, oocytes, zygotes, early cleavage stage embryos and blastocysts is an integral part of almost every human IVF programme. Moreover, the cryopreservation of these types of cells by direct plunging into liquid nitrogen usually requires high cryoprotectant concentrations with consequent cytotoxic effects. This review covers the history of this problem, and in this light offers an explanation, through physico-chemical concepts, for one of the most recent developments in this area: the recovery of motile and potent spermatozoa after cryoprotectant-free vitrification.

New technology for vitrification and field (microscope-free) warming and transfer of small ruminant embryos.

This study was designed to test the efficiency of recently developed vitrification technology followed by microscope-free thawing and transfer of sheep embryos. In a first set of experiments, in vivo derived embryos at the morula to blastocyst stage were frozen in an automated freezer in ethylene glycol, and after thawing and removal of cryoprotectants, were transferred to recipient ewes according to a standard protocol (control group). A second group of embryos were loaded into open-pulled straws (OPS) and plunged into liquid nitrogen after exposure at room temperature to the media: 10% glycerol (G) for 5 min, 10% G+20% ethylene glycol (EG) for 5 min, 25% G+25% EG for 30s; or 10% EG+10% DMSO for 3 min, 20% EG+20% DMSO+0.

Implantation despite an extensive endometrial defect after hysteroscopic resection of symptom-free residual trophoblastic tissue 15 months after cesarean section.

Successful implantation occurred after embryo transfer in the presence of an extensive endometrial defect after hysteroscopic resection of residual trophoblastic tissue 15 months after cesarean section. At the end of hysteroscopic surgery the anterior uterine wall seemed smooth, although ultimately no endometrium was left in that part and in parts of the fundus. Thus implantation is possible even with extensive endometrial defects.