Background: Failed fertilization after intracytoplasmic sperm injection (ICSI) can be due to a reduced oocyte-activation capacity caused by reduced concentrations and abnormal localization of the oocyte-activation factor phospholipase C (PLC) zeta. Patients with this condition can be helped to conceive by artificial activation of oocytes after ICSI with calcium ionophore (assisted oocyte activa...

BACKGROUND Failed fertilization occurs in 2-3% of ICSI cycles and is mainly due to lack of oocyte activation. Heterologous ICSI of patient's sperm in mouse oocytes allows discrimination between sperm- and oocyte-related aetiologies of activation failure. Assisted oocyte activation (AOA) by Ca-ionophore treatment can initiate fertilization in subsequent therapeutic ICSI. We report on diagnosis a...

BACKGROUND The purpose of this study was to investigate the chromosomal complement and developmental potential of in-vitro matured murine oocytes following ICSI by human sperm. METHODS Heterologous ICSI fertilization between mouse oocytes and human sperm was employed in order to overcome the reduced fertilization rates observed after conventional IVF due to zona hardening during in-vitro matu...

STUDY QUESTION Does calcium oscillatory pattern analysis following heterologous intra-cytoplasmic sperm injection (ICSI) of human sperm into mouse oocytes lead to diagnostic and prognostic information for patients suffering from ICSI fertilization failure? SUMMARY ANSWER We found that calcium oscillatory pattern analysis following heterologous ICSI has the strength to reveal, for the individu...

BACKGROUND Concerns regarding the safety of ICSI have been intensified recently due to increased risk of birth defects in ICSI born children. Although fertilization rate is significantly higher in ICSI cycles, studies have failed to demonstrate the benefits of ICSI in improving the pregnancy rate. Poor technical skill, and suboptimal in vitro conditions may account for the ICSI results however,...

BACKGROUND The present study highlights basic physiological differences associated with oocyte maturation and ageing. The study explores the fertilizing capacity and resistance to injury of mouse oocytes at different stages of maturation and ageing following IVF and ICSI. Also, the study examines the developmental competence of embryos obtained from these oocytes. The outcome of the study suppo...

Egg activation, which is the first step in the initiation of embryo development, involves both completion of meiosis and progression into mitotic cycles. In mammals, the fertilizing sperm delivers the activating signal, which consists of oscillations in free cytosolic Ca(2+) concentration ([Ca(2+)](i)). Intracytoplasmic sperm injection (ICSI) is a technique that in vitro fertilization clinics u...

Mice are ideal models for ICSI experiments because of the ease of culturing eggs/embryos in vitro and the availability of ample genetic information. Unfortunately, it has been extremely difficult. In this study we improved the mouse ICSI method by using a new holding pipette that was made of two pipettes such that one pipette was pulled and heat merged into the other one. The outer pipette ...

Artificial oocyte activation to overcome failed fertilization after intracytoplasmic sperm injection (ICSI) in human oocytes typically employs Ca2+ ionophores to produce a single cytosolic Ca2+ increase. In contrast, recombinant phospholipase Czeta (PLCz) causes Ca2+ oscillations indistinguishable from thoseoccurring during fertilization, but remains untested for its efficacy in a scenario of I...

BACKGROUND Aggressive immobilization of sperm prior to ICSI significantly improves fertilization rates, but the mechanism of this effect is not yet clear. This study was performed in order to assess the characteristics of mechanically immobilized human sperm by transmission electron microscope (TEM). METHODS Sperm obtained from ejaculated semen samples from three different donors were immobil...