Prevention of twin pregnancy after in-vitro fertilization or intracytoplasmic sperm injection based on strict embryo criteria: a prospective randomized clinical trial.

A prospective randomized study comparing single embryo transfer with double embryo transfer after in-vitro fertilization or intracytoplasmic sperm injection (IVF/ICSI) was carried out. First, top quality embryo characteristics were delineated by retrospectively analysing embryos resulting in ongoing twins after double embryo transfer. A top quality embryo was characterized by the presence of 4 or 5 blastomeres at day 2 and at least 7 blastomeres on day 3 after insemination, the absence of multinucleated blastomeres and <20% cellular fragments on day 2 and day 3 after fertilization.

Characterization of a top quality embryo, a step towards single-embryo transfer.

In most in-vitro fertilization (IVF)/intracytoplasmic sperm injection (ICSI) programmes approximately one ongoing pregnancy in three is multiple. The need to characterize embryos with optimal implantation potential is obvious. We retrospectively examined all of 23 double transfers resulting in ongoing twins, occurring between January 1, 1996 and May 19, 1997.

Cervical pregnancy: three case reports and a review of the literature.

Three cases of cervical pregnancy are described: the incidence, the diagnostic approach and different therapeutic managements used for this rare type of ectopic pregnancy are discussed. The last case shows that hysterectomy can be avoided by early diagnosis and by an adequate tamponing technique to control haemorrhage. For this purpose, a three-way Dufour catheter was successfully used to rinse the uterus with heated saline, allowing evacuation of intrauterine blood after curettage and to tampon the cervix.

Substituent effects on reactivity and spectral parameters of cephalosporins.

The chemical reactivity of a series of cephalosporins is examined as a function of the substituents at positions 3 and 7. In most cases, the nature of the C7 side chain has a minor influence on the beta-lactam reactivity. But in the case of amino-containing C7 substituents, when intramolecular nucleophilic attack may occur, the reactivity may be greatly increased.

Conformational study of two polymorphs of spiperone: possible consequences on the interpretation of pharmacological activity.

A second polymorph of spiperone, 8-[3-(p-fluorobenzoyl)-propyl]-1-phenyl-1,3,8-triazaspiro[4,5] decan-4-one, has been isolated and characterized by thermal analysis and IR spectrometry. Its structure was solved by X-ray diffraction analysis. The results are compared with those previously obtained on spiperone, the main difference being in the conformation of the side chain and in the nature of the hydrogen bonding.