A prospective study on intracytoplasmic sperm injection (ICSI) was performed to evaluate the effect of the position of the polar body relative to the opening of the injection needle during sperm injection, and of the person who performs the injections on fertilization, cleavage, and pregnancy rates. This study included 173 couples undergoing 313 ICSI cycles from September 1995 to December 1997....

A penetrated ovum was recovered from the oviduct of a 33 year old surgical patient who had had sexual intercourse 26 hr before the operation. The ovum was in the pronuclear stage. The ooplasmic organelles were mainly represented by mitochondria, endoplasmic reticulum components, and Golgi elements. Small vesicles were found in the space between the two sheets of the pronuclear envelope. These v...

A single dose of 3/~g/g b.w. colchicine was intraperitoneally injected to female Chinese hamsters with a normal estrous cycle at the onset of the formation of the first meiotic spindle. Morphologically abnormal secondary oocytes having one or two extremely large first polar bodies occurred frequently, i.e., 47 (11.3~) out of 416 oocytes. In 30 of them, chromosome analysis was successful with bo...

STUDY QUESTION When a chromosome aneuploidy is detected in the first polar body and a reciprocal loss or gain of the same chromosome is detected in the second polar body, is the resulting embryo usually aneuploid for that chromosome? SUMMARY ANSWER When reciprocal aneuploidy occurs in polar bodies, the resulting embryo is usually normal for that chromosome, indicating that premature separatio...

Parthenogenetic embryos are an ethically acceptable alternative for the derivation of human embryonic stem cells. In this work, we propose a new strategy to produce bovine parthenogenetic embryos inhibiting the emission of the first polar body during in vitro maturation, and allowing the extrusion of the second polar body during oocyte activation. Cytochalasin B, an inhibitor of actin microfila...