Kristof Chwalisz

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Antiprogestins (APs) inhibit estradiol (E(2))-stimulated endometrial growth in women and nonhuman primates, but the mechanism of this "antiestrogenic" action is unknown. Here, we report that APs up-regulate endometrial androgen receptor (AR) in both women and macaques, an effect that might play a role in the antiproliferative effects of APs on the primate(More)
Preterm labour and resultant preterm birth are the most important problems in perinatology. Countless efforts have failed to establish a single effective treatment of preterm labour, partly because the mechanisms regulating the uterus and cervix during pregnancy are not well understood. New knowledge is needed to inhibit early progression of labour (uterine(More)
Selective progesterone receptor modulators (SPRMs) represent a new class of progesterone receptor ligands. SPRMs exert clinically relevant tissue-selective progesterone agonist, antagonist, or mixed agonist/antagonist effects on various progesterone target tissues in vivo. Asoprisnil (J867) is the first SPRM to reach an advanced stage of clinical(More)
Studies were conducted to assess progesterone antagonists (PAs) and progesterone receptor modulators (PRMs) with respect to PR agonistic and antagonistic activities in vivo. These properties are not always adequately reflected in transactivation in vitro models. Studies were performed in pregnant rats, estrogen-primed rabbits (McPhail -Test), and cycling(More)
OBJECTIVE To compare the expression of endometrial P receptors (PR) levels with markers of endometrial receptivity during the window of implantation. DESIGN Prospective, controlled study to examine endometrial PR and three cycle-specific integrins in endometrial biopsies obtained during the window of implantation. SETTING An academic teaching hospital.(More)
The aim of this study was to determine if nitric oxide (NO) production and nitric oxide synthase (NOS) isoforms change within the uterus and cervix during pregnancy and labour either at term or preterm. NO production was compared in the rat uterus and cervix of non-pregnant and pregnant rats on days 18-22 prior to labour, day 22 during delivery, 1 day(More)
The progesterone antagonist onapristone was used in guinea pigs during late pregnancy (43 +/- 2 days after coitus) and before term (day 61 after coitus) to investigate the role of progesterone on uterine reactivity to exogenous oxytocin, concentration of oxytocin receptors, and gap junctions in the myometrium. Onapristone priming increased the ability of(More)
A distinct spatial and temporal pattern of connexin26 and connexin43 (cx26 and cx43) expression was observed in the rat endometrium in response to embryo implantation; however, connexin expression was suppressed during the preimplantation period. Pseudopregnant rats did not show connexin mRNA, while artificial decidualization induced by a scratch led to a(More)
Nitric oxide (NO) is considered to be an important local mediator that suppresses uterine contractility in rats and rabbits during pregnancy until term. The aim of this study was to investigate the mRNA concentrations for the three isoforms of nitric oxide synthase (NOS) in rat uterus and cervix and to determine whether alterations occur in association with(More)
BACKGROUND A reliable means of menstrual suppression would greatly improve the quality of life for women. Information is lacking on the direct endometrial effects and appropriate dosages of new antiprogestins that may be useful for this purpose. METHODS The current work evaluated three different systems in macaque monkeys. First, the range of doses of two(More)