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H M Beier

Publications and source records attributed to H M Beier.

At least 55 records · Page 3Linked to original sources
PubMed1994

Modification of endometrial cell biology using progesterone antagonists to manipulate the implantation window.

The preimplantation effects of progesterone antagonists on the cell biology of the endometrium, corpus luteum function and interactions between these two organs have been studied. The antagonists lilopristone (ZK 98.734) and onapristone (ZK 98.299) were initially given per os to rabbits early or late in pseudopregnancy in combination with human chorionic gonadotrophin (HCG). These protocols were then modified to include hysterectomy or luteotrophic support with 17 beta-oestradiol. Given alone, the antagonists gave rise to endometrial regression (inhibition of epithelial proliferation and differentiation, increase of apoptosis). The simultaneous addition of oestradiol did not alter these findings. A rapid luteolysis occurred when the antagonists were given in late pseudopregnancy, but not if combined with oestradiol or hysterectomy. The endometrium was capable of renewal and of sustaining implantation if the corpora lutea survived or oestradiol was administered, and transferred blastocysts displayed normal implantation and normal embryonic development. These events did not occur when the antagonists were given during late pseudopregnancy without any steroid supplement. Progesterone antagonists can evidently exert a direct inhibitory effect on the endometrium, possibly with a later indirect luteolytic effect via endometrial mediators. Simultaneous addition of a proper luteotrophic signal results in corpora lutea which are refractory to lysis, so revealing a potential functional dissociation between endometrium and corpus luteum. The endometrium has the capacity to differentiate normally after an interrupted transformation and becomes receptive and sustains normal pregnancy, due to an expanded lifespan of the corpora lutea and a transposition of the implantation window. Uterine secretions from patients undergoing in-vitro fertilization, collected at the onset of the luteal phase, were evaluated by SDS-PAGE densitometry. The protein profiles gave indications of an adequate luteal phase pattern and of a receptive preimplantation phase. These results open the prospect of manipulating the human implantation window.

Animals↗
PubMed1994

Effects of persistent chlorinated hydrocarbons on fertility and embryonic development in the rabbit.

The commercial polychlorinated biphenyl (PCB) formulation Aroclor 1260 (4 mg/kg body weight), technical grade dichlorodiphenyltrichloroethane (DDT; 3 mg) and Lindane (gamma-hexachlorocyclohexane; 0.8 mg) were administered orally, either separately or in combination, to sexually mature female rabbits three times per week for 12-15 weeks. Oviductal and uterine luminal fluid, cleavage stage embryos (day 1 post coitum), blastocysts (day 6), fetuses, exocoelic fluid and placentae (day 11) were analysed, firstly for chlorinated hydrocarbon residues, and secondly for embryonic and fetal development. The doses applied were well tolerated by the treated animals. PCB and DDT accumulated in uterine secretions (day 6) but not in oviductal luminal fluid (day 1). Both chlorinated hydrocarbons were found in preimplantation blastocysts. Residues in day 11 fetuses were 16- (DDT) or 18-fold (PCB) higher than in day 6 blastocysts. Significant amounts were also detected in placental tissue and in exocoelic fluid. A specific accumulation of the highly chlorinated biphenyl congener no. 180 was noted in fetuses, placentae and exocoelic fluid. The clear accumulation of the chlorinated hydrocarbon compounds in luminal fluid and embryonic tissue is contrasted by rather weak effects on fertility. No statistically significant differences between treated animals and controls were observed for fertilization rate and pre- and post-implantation (up to day 11 post coitum) losses. However, in females exposed to PCB, a 20% higher loss of blastocysts was noticed, as compared with controls (P > 0.05). This effect was shown on day 6 of embryonic development and may be due to the embryotoxic activities of PCB.

Animals↗
PubMed1994

Cervical ripening with the cytokines interleukin 8, interleukin 1 beta and tumour necrosis factor alpha in guinea-pigs.

It has been suggested that the collagenolytic enzymes released from white blood cells which infiltrate the pregnant human uterine cervix at term are responsible for connective tissue changes which take place during the ripening process. Similarly, an infiltration of inflammatory cells occurs in pregnant guinea-pigs either spontaneously at term or at preterm after treatment with the antiprogestin onapristone. The objective of this study was to evaluate the effects of the inflammatory cytokines interleukin 8 (IL-8), interleukin 1 beta (IL-1 beta), tumour necrosis factor alpha (TNF-alpha) and a combination of IL-1 beta and TNF-alpha on cervical ripening in guinea-pigs during advanced pregnancy. The cytokines were applied locally (intracervically) in a gel for 2 days and the effects were assessed on the third day by both extensibility measurements and morphological evaluation. IL-8 treatment on days 42 and 43 post coitum (p.c) and on days 48 and 49 p.c. (term: day 67 +/- 3 p.c.) significantly (P < 0.05) increased cervical extensibility at both stages of pregnancy. Although IL-1 beta treatment (days 42 and 43 p.c.) led to a slight increase in cervical extensibility, this effect was not statistically significant. An electron microscope study performed on days 48 and 49 p.c. revealed a pronounced cervical ripening accompanied by the dissolution of collagen fibres, stromal oedema and the infiltration of polymorphonuclear leukocytes in all cytokine-treated groups. The morphological effects of IL-8 and IL-1 beta were indistinguishable from those observed during normal cervical ripening at term.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1994

Effects of persistent chlorinated hydrocarbons on reproductive tissues in female rabbits.

The female rabbit was used to study (i) accumulation of lipophilic chlorinated hydrocarbons in genital tract tissues and (ii) subsequent morphological and functional effects after long-term low-dose exposure. Polychlorinated biphenyl (PCB), 1,1-di(p-chlorophenyl)-2,2,2-trichloroethane (DDT) and gamma-hexachlorocyclohexane (gamma-HCH) (dosages: 4, 3 and 0.8 mg per kg body weight, respectively) and a combination of these three components (and dosages) were administered to sexually mature rabbits over a period of 12-15 weeks. The animals were killed shortly before and at various times after ovulation. Accumulation of chlorinated hydrocarbons was high in ovarian, oviductal and uterine tissues, in follicular fluid and clearly detectable in uterine secretions. In follicular fluid, the concentration and patterns of congeners and isomers of PCB and DDT were distinctly different from serum. DDT- and gamma-HCH-treated animals showed a significantly reduced ovulation rate (P < 0.002 and 0.05, respectively). During early pregnancy DDT decreased serum progesterone levels and changed the protein pattern of uterine secretion. Functional effects, however, were much less expressed compared with the highly significant accumulation of the persistent organochlorines in the genital tract.

Animals↗
PubMed1993

High frequency of DNA ploidy abnormalities in preimplantation embryos of the rabbit.

The DNA ploidy of Feulgen-stained cell nuclei of in vivo preimplantation rabbit embryos was assayed by cytophotometry. DNA ploidy abnormalities were detected in single-cell nuclei readings by the criterion of > or = 5C DNA. These hypermodal DNA contents are referred as to DNA aneuploidy. Two, 4 and 6 days old rabbit embryos, all of normal gross morphology, were investigated. The incidence of embryos with DNA ploidy abnormalities increased from 17% in 2-day-old cleavage stages to 51% in 6-day-old expanded blastocysts. All these embryos were mosaics and the percentage of DNA aneuploid nuclei per embryo did not usually exceed 9%. Fifteen percent of the expanded blastocysts, however, contained up to 23% abnormal nuclei. Throughout the embryonic stages studied, the DNA content of abnormal nuclei was remarkably constant and averaged 5.8C. DNA aneuploid and euploid blastocysts did not differ in size. A maternal FSH treatment did not influence the DNA ploidy. This is the first report on the DNA ploidy pattern in preimplantation rabbit embryos. Our results indicate that DNA aneuploidy of single blastomeres is common in this species and occurs more often than generally assumed. The embryonic viability does not seem to be affected by the presence of DNA aneuploid blastomeres supporting earlier findings that a limited number of abnormal blastomeres is compatible with normal preimplantation development.

Aneuploidy↗
PubMed1992

Distribution of estrogen and progesteron receptors in the uterus: an immunohistochemical study in the immature and adult pseudopregnant rabbit.

In order to clarify the distribution and content of estrogen (ER) and progesteron receptors (PR) under changing hormonal influences within the various cell populations of the uterus (glandular and luminal endometrial epithelium, stroma, myometrium), immunohistochemical determinations using specific monoclonal antibodies were made. To correlate the immunohistochemical findings with peripheral hormone levels and specific tasks of the endometrium, 17 beta-estradiol and progesterone serum levels were measured and cell proliferation determined by use of BrdU-labelling-immunohistochemistry. At the subcellular level ER and PR were located exclusively in the cell nuclei of female rabbits, which were either immature and lacking any peripheral hormone levels or were pseudopregnant (d0-d8 p.hCG). In the immature rabbits a general faint ER and PR immunostaining was found. In addition to a general increase in ER and PR in all cell populations estrous rabbits (d0 p.hCG) showed a significant rise of ER in the epithelial cells and of PR in the myometrium. Within the epithelial cells and the myometrium the ER dropped heavily within a few days of pseudopregnancy. The PR, however, increased sharply during the first two days of pseudopregnancy and decreased gradually following d4 p.hCG. A close relationship was observed between the high PR content and the proliferation rate of the epithelial cells on d2 p.hCG. In spite of the more rapid decrease of ER compared with PR, the glandular epithelium retained positive immunostaining. In the stroma the ER and especially PR content did not change significantly during the course of pseudopregnancy suggesting that some of the well-known differentiation events in the luminal epithelium may be mediated by the stroma.

Aging↗
PubMed1992

Numerical chromosome anomalies after fertilization of freeze-thawed mouse oocytes.

The chromosome complement of first cleavage stage mouse embryos was analyzed to investigate the effect of slow freezing-fast thawing cryopreservation on chromosome numbers by comparing these numbers with those found fresh after fertilization of control oocytes. Fewer frozen-thawed (34.1%) than control oocytes (75.0%) cleaved to the 2-cell stage after in vitro fertilization. The incidence of hyperploidy was significantly increased by freezing (4.5% vs. 0% in controls). Polyploidy was not significantly affected (17.0% for freeze-thaw embryos vs. 26.2% for controls).

Aneuploidy↗
PubMed1992

Luteal control of endometrial receptivity and its modification by progesterone antagonists.

The objective of this study was to determine preimplantational effects of progesterone antagonists (PA) on the cell biology of the endometrium, on corpus luteum (CL) function and on the complex interactions between these two organs. The PA onapristone (ZK 98.299) or lilopristone (ZK 98.734) was given to pseudopregnant rabbits at days 5, 6, and 7 p.hCG. Three treatment protocols were investigated: Exp I, onapristone or lilopristone treatment only; Exp II, onapristone treatment after hysterectomy at day 1 p.hCG; Exp III, onapristone treatment together with 17 beta-estradiol, which represents the ultimate luteotropic hormone in the rabbit. In Exp I, onapristone and lilopristone gave rise to endometrial regression (inhibition of epithelial proliferation and differentiation, increase of apoptosis). Simultaneous addition of 17 beta-estradiol in Exp III did not alter these findings. A rapid luteolysis was found in Exp I. In Exp II and III, however, onapristone was unable to impair luteal development and function. Due to the unaffected CL in Exp III and due to the 17 beta-estradiol substitution, the endometrium was capable of starting a new transformation, which met all requirements for receptivity at day 12 p.hCG. Transfers of day 4 p.c. blastocysts from untreated donors into such delayed secretion recipient rabbits at days 12 p.hCG resulted in normal implantations and normal embryonic development. Contrary to Exp III, the missing of any luteotropic substitutions in Exp I resulted in a complete inhibition of further uterine transformation. The present findings suggest that PA can exert a direct inhibitory effect on the endometrium, which is followed by an indirect luteolytic effect via endometrial mediators. The simultaneous addition of a proper luteotropic signal to the PA protocol results in survival of CL. Furthermore, this prolongation of the CL life span can be interpreted as a functional dissociation of the endometrium from the CL.

Animals↗
PubMed1991

Effect of in vitro culture on the dynamics of uteroglobin distribution in rabbit blastocysts.

The purpose of this study was to investigate the localization and transport of uteroglobin in normal rabbit blastocysts (day 4-day 6 p.c.) and in those cultured for 6-48 h in vitro, using a specific radioimmunoassay and immunocytochemistry. The results of the radioimmunoassay showed that in day 4 p.c. blastocyst tissue (based on homogenate measurements) a significant decrease of the uteroglobin content started after only 6 h of culture in vitro. A significant concomitant rise of uteroglobin was observed in the culture medium after 12 h of in vitro culture. Using immunocytochemistry it was not possible to detect uteroglobin in any compartment of the non-cultured or in vitro cultured day 4 p.c. blastocysts. The efflux of uteroglobin down a concentration gradient was confirmed by the immunocytochemistry in non-cultured and in vitro cultured day 5 p.c. and day 6 p.c. blastocysts. Uteroglobin immunoreactions were mainly detected in non-cultured blastocysts (day 5 and 6 p.c.) in large vesicles of the trophoblast cells. In addition endocytotic vesicles at the inside of the apical membrane of trophoblast cells, some cell debris within the perivitelline space and the neozona were labelled. During in vitro culture of day 5 and 6 p.c. blastocysts, uteroglobin labelling in the coverings did not change. In non-cultured and cultured day 5 and 6 p.c. blastocysts neither the compartments of the embryoblast, the endoderm cells nor the blastocyst cavity showed any uteroglobin immunoreactions. After only 6 h of in vitro culture, uteroglobin immunoreactions were no longer found within the trophoblast cells. The reaction did not reappear during the course of in vitro culture up to 48 h, suggesting a complete lack of de novo synthesis of uteroglobin by blastocysts.

Animals↗
PubMed1991

The dynamic structure of rabbit blastocyst coverings. III. Transformation of coverings under non-physiological developmental conditions.

Under physiological conditions the zona pellucida disappears in the rabbit between Day 3 and early Day 4 post coitum (p.c.) and is replaced by a new layer, the neozona. The dissolution of the zona pellucida and the formation of the neozona was investigated in three different experimental approaches, all of them characterized by non-physiological developmental conditions for the embryo: Prevention of embryo migration from the oviduct into the uterus by postcoital (48 h p.c.) tubal ligation, in vitro culture, and asynchronous embryo transfer into uteri of recipient rabbits. Embryos of age 2 1/2, 3, 4 and 4 1/2 days p.c. were cultured for 12 to 72 h. The media used for in vitro culture were supplemented with BSA, serum or with uterine secretions that were collected either synchronously or asynchronously to the developmental stage of the cultured embryos. Three-day-old embryos were transferred into uteri of pseudopregnant foster rabbits of either synchronous (Day 3) or asynchronous stages (Day 0, 2, 4, 5, 6) and were recovered 24 to 72 h after transfer. The transformation of the coverings was evaluated by light and transmission electron microscopy. The dissolution of the zona pellucida was greatly disturbed in tube-locked embryos, and in cultured embryos if standard protein supplements (BSA or serum) had been used for in vitro culture. In many cases the zona was still completely preserved after 2 or 3 days in culture, at a time when it normally would have already been replaced by the neozona in vivo. The dissolution in vitro, however, progressed incomparably better if the culture medium had been substituted with synchronous or asynchronous uterine secretions. The formation of the neozona could not be verified in cultured blastocysts. After embryo transfer, the dissolution of the zona pellucida was completed in most cases by 2 days after transfer, irrespective of the recipients' progestational stage. Present results indicate that uterine components are essential for the dissolution of the rabbit zona pellucida. These components appear to be present in the uterine cavity constitutively, i.e. independently of the uterine progestational transformation, and need not be in synchrony with the embryo's developmental stage for dissolution of the zona. Normal formation of the neozona does not take place under the non-physiological developmental conditions of in vitro culture.

Animals↗
PubMed1991

Inhibition of the estradiol-mediated endometrial gland formation by the antigestagen onapristone in rabbits: relationship to uterine estrogen receptors.

There is evidence from previous studies that progesterone antagonists (antigestagens) modify estrogen responses at endometrial and myometrial levels without having affinity to the estrogen receptor (ER). The purpose of the present study was to investigate the influence of the antigestagen onapristone (ZK 98 299) on the uterus in ovariectomized (OVX) estradiol (E2)-substituted rabbits (3.0 micrograms/animal.day). The animals were treated for 8 days with different doses of onapristone (3.0, 10.0, and 30.0 mg/animal.day, sc). Uterine growth was not influenced by onapristone compared to that in OVX E2-substituted controls. However, morphological (light microscopy, transmission electron microscopy) and morphometric criteria indicated that there was a significant dose-dependent inhibition of the estrogen-induced gland formation within the endometrium and degenerative changes in glandular epithelial cells. By contrast, there were morphological signs of activation of the endometrial stroma (proliferation, increased capillarization, and vascularization, edema) above the level of E2-treated animals. A dose-dependent increase in the concentration of uterine cytosolic ER, nuclear ER, and ER mRNA (ER mRNA) was measured in uterine homogenates after onapristone treatment compared to values in OVX E2-substituted controls. Immunocytochemical analysis of ER in uterine sections suggests that the increase in ER after onapristone treatment took place predominantly in the myometrium and surface epithelium. To examine whether the observed interference was mediated via the progesterone receptor (PR), E2-substituted rabbits were treated, in a separate experiment, with onapristone (10.0 mg/animal.day, sc) and various doses of progesterone (1.0, 3.0, and 10.0 mg/animal.day, sc). Progesterone reversed all onapristone-induced changes, indicating that the observed effects were mediated via the PR. The data indicate that the antigestagen onapristone interacts with estrogen action in the absence of the natural PR ligand. The increase in ER and ER mRNA concentrations after onapristone treatment in OVX E2-treated animals suggests that this antigestagen abolished an inhibitory action of the unoccupied PR on ER biosynthesis.

Animals↗
PubMed1991

Dissociation of corpus luteum, endometrium and blastocyst in human implantation research.

We describe a well-established approach for studying the parameters and mechanisms of synchronization or desynchronization between the maternal and embryonic systems before implantation. It is useful for inducing 'delayed secretion' of the endometrium by different endocrine interventions, which dissociate the endometrial transformation from its control by the corpus luteum. The technique has been achieved by means of direct progesterone antagonists which competitively bind to the progesterone receptor and, in turn, inhibit the physiological effects of progesterone. During the luteal phase, secretory protein patterns indicate the receptive stage of the endometrium. Evidence is presented to show that these patterns, analysed by electrophoresis and densitometry, define the time at which an embryo transfer is promising for implantation and establishment of pregnancy.

Animals↗
PubMed1990

Development of preimplantation rabbit embryos in uterine flushing-supplemented culture media.

The development of cultured rabbit preimplantation embryos grown in standard media (Ham's F-10 or BSM II supplemented with bovine serum albumin (BSA) or homologous serum) or in Ham's medium supplemented with uterine flushings was compared. The uterine flushings derived from donors of 0.5-6 years of age. Uterine flushing supplemented media were used natively or after treatments like sterilization by filtration, lyophilization, three times freezing/thawing, heat denaturation, dialysis, or ultrafiltration. Compared with in vivo controls, embryonic growth was substantially reduced during in vitro culture, demonstrably by smaller diameters and impaired cell proliferation (measured by thymidine incorporation). The growth retardation was more pronounced in blastocysts (recovered at day 4 post coitum [p.c.]) than in morulae (recovered at day 3 p.c.). Development in uterine flushing media was notably better than in standard media but did not comply with in vivo development. Highest thymidine incorporation was observed in media with increased concentrations of uterine secretions and after sequential supplementation of flushings from subsequent progestational stages. Advanced donor ages, heating up to 80 degrees C, freezing, and lyophilizing did not affect incorporation data statistically significantly, whereas sterilization by filtration, ultrafiltration, and dialysis led to a significantly reduced thymidine incorporation in the cultured embryos. The positive effects of uterine flushing supplementation are attributed to the supply of components more adjusted to the needs of the cultured embryos and/or to a reduction of pathological effects in vitro like washing out of nutritive and regulatory components from the embryo into the surrounding culture medium.

Animals↗