An aspiration system, incorporating a regulated vacuum pump, was used to examine, in vitro, some factors that may affect oocyte collection. In an open aspiration system, as the length of the needle was increased, or the internal diameter decreased, the velocity (and flow rate) of aspirated fluid decreased. There was a difference, however, between experimental flows and those predicted by Hagen-...

When immature bovine oocytes are released from their follicles and are cultured in standard maturation medium, they resume the first meiotic division. The alteration of basic maturation conditions can affect oocyte competence significantly, as reflected by the morula and blastocyst yield after in vitro fertilization. The conditions used from the beginning of maturation up to the blastocyst stag...

Cryopreservation of growing oocytes enriches the choice of timing and location of artificial embryo production. However, completion of oocyte growth after warming is crucial when using such cryopreserved oocytes. Our research objective was to develop a sequential system that incorporates cryopreservation of growing bovine oocytes and their subsequent in vitro growth. Oocyte-granulosa cell compl...

Polymeric nanoparticles (NPs) are produced using bio-compatible and bio-degradable materials such as PLGA (Poly(lactic-co-glycolic acid)). This technology provides a valuable tool to deliver molecules the subcellular level with relatively low risk of cytotoxicity. However their use in field reproductive biotechnology is not yet scientifically substantiated. The aim present study was test if NPs...

A method is described by which nuclei associated with some cytoplasm can be rapidly prepared from a suspension of cells. The method involves the use of lysolecithin and bovine serum albumin. Oocytes of Xenopus laevis were injected with about 200 nuclei perpared from human HeLa cells by this method. Nuclei were deposited in oocyte cytoplasm, in the oocyte nucleus, or in the dispersed contents of...

Oocyte meiotic resumption is triggered by the ovulatory gonadotropin surge; in cattle, angiotensin II (AngII) and prostaglandins (PG) are key mediators of this gonadotropin-induced event. Here, we tested the hypothesis that progesterone (P(4)) is also involved in oocyte meiotic resumption induced by the gonadotropin surge. In Experiment I, P(4) induced nuclear maturation in a dose-dependent man...

Various morphological and cytological traits of oocytes and their surrounding cumulus cells may be used to select oocytes for assisted reproduction. However, even with careful selection, successful IVF and subsequent embryo development remain uncertain. The factors that ensure oocyte competence are unclear and other approaches to assessing developmental potential must be explored. With the cons...

this study investigated the effect of different harvesting techniques on the recovery rate and quality of bovine cumulus oocyte complexes (cocs) and their subsequent developmental competence including in vitro maturation, fertilization and blastocyst formation. the cocs were retrieved from slaughter ovaries using aspiration, slicing, or aspiration followed by slicing. the cocs were examined mic...