One of the technical bottlenecks in producing nonhuman primate models is that current assisted reproductive techniques, such as in vitro culture and frozen conservation of multicell-stage embryos, often result in poor embryo quality and subsequently lead to low birth rates. We investigated whether pronuclear embryo transfer can be used as an effective means for improving pregnancy and live birt...

Abstract While intracytoplasmic sperm injection (ICSI) is an asset in human Assisted Reproduction Technologies (ART), its outcomes, terms of blastocyst, still unacceptably low ruminants. The picture typically found ICSI derived bovine and ovine embryos asymmetry between a high activation rate, marked by pronuclear development, first cleavage rate. Abnormal centriole function has been indicated ...

TABLE OF CONTENTS INTRODUCTION ................................................................................... 199 I. THE LEGAL BACKGROUND ........................................................ 200 II. THE SCIENCE............................................................................ 204 A. Insemination...................................................................... 205 B. Form...

This study was conducted to develop a method for transplanting nuclei in bovine embryosand to test the development of several stages of donor nuclei transplanted to enucleated pronuclear recipient embryos. Pronuclear embryos were centrifuged to reveal nuclei. Nuclei were removed without penetrating the plasraa membrane as membrane-bound karyoplasts, and were inserted into enucteated zygotes by ...

As the male and female pronuclei of flushed rabbit tubal ova approach each other, numerous projections appear on the proximal surfaces, resulting in a severely irregular appearance. Each pronuclear envelope consists of 2 parallel membranes separated by a distance of 40-60 nm; annular ' pores' are conspicuous in regions of pronuclear approximation. Stacks of smoothsurfaced membranes form paralle...

Boar spermatozoa were prepared for intracytoplasmic sperm injection (ICSI) by two different treatments to facilitate sperm chromatin decondensation and improve fertilisation rates after ICSI in pigs: spermatozoa were either frozen and thawed without cryoprotectants, or treated with progesterone. Morphological changes of the sperm heads after the treatments were examined and then the activation ...

Based on observations of markers for DNA lesions, such as phosphorylated histone H2AX (γH2AX) and open DNA ends, it has been suggested that post-meiotic DNA double-strand breaks (PM-DSBs) enable chromatin remodeling during animal spermiogenesis. However, the existence of PM-DSBs is unconfirmed, and the mechanism responsible for their formation is unclear. Here, we report the first direct observ...