DNA topoisomerases I and II in human mature sperm cells: characterization and unique properties.

Background: The condensed state of the human sperm's chromatin is essential for the compact structure of the spermatozoon head, which is important for the fertilization process. The enzymes DNA topoisomerases (topo I and topo II) are responsible for the topological structure of the chromatin in somatic cells. The activities and the characterization of topoisomerases in mature human sperm cells have not been previously investigated.

Blastocyst-stage embryo transfer in patients who failed to conceive in three or more day 2-3 embryo transfer cycles: a prospective, randomized study.

Objective: To compare blastocyst-stage embryo transfers (ETs) with day 2-3 ETs in patients who failed to conceive in three or more day 2-3 IVF/ET cycles.

Design: Prospective, randomized.

Setting: Fertility unit in a university medical center.

Monozygotic twins following blastocyst transfer: a report of two cases.

Several studies have shown an increased risk for monozygotic twinning after fertilization treatments. We present the clinical and sonographic characteristics of two monozygotic twin cases following blastocyst transfer. It is suggested that delayed transfer of the embryo in the blastocyst stage is a contributing factor to monozygotic twinning.

Does transcervical intra-fallopian insemination improve pregnancy rates in cases of oligoteratoasthenozoospermia? A prospective, randomized study.

The relatively low pregnancy rates (PR) after treatment of patients with oligoteratoasthenozoospermia (OTA) result in a search for different treatment modalities. The objective of this study was to assess the efficacy of transcervical intrafallopian insemination (IFI) with husband's semen in comparison to intrauterine insemination (IUI) in couples with OTA. A prospective, randomized study included 30 couples with OTA-related infertility (according to WHO criteria).

Chlamydial IgG and IgA in serum and follicular fluid among patients undergoing in vitro fertilisation.

The point prevalence of IgG and IgA antibodies to Chlamydia was analyzed in serum and follicular fluid in 63 patients undergoing in vitro fertilisation (IVF) in comparison to sera of 298 healthy women by the single serovar (L2) inclusion immunoperoxidase assay (IPA). The presence of specific IgG and IgA to Chlamydia in follicular fluid was demonstrated. No statistical association was found between the presence of specific Chlamydia IgG and IgA in serum and follicular fluid to oocyte fertilization.