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PubMed1977

Tumor cell locomotion--a factor in metastasis formation? Influence of cytochalasin B on a tumor dissemination pattern.

The influence of Cytochalasin B (CB) on TA3 ascites tumor cells was studied in vivo in order to assess whether CB-induced cell paralysis would affect the transplanation behavior of the cells and in particular tumor distribution after IV cell infusion ("experimental metastases"). Tumor cell pre-treatment with CB (1 mug/ml) did not alter the SC or IV transplantability of TA3 cells. Pre-treatment with 10 mug/ml CB, in contrast, consistently increased the incidence and number of extra-pulmonary tumor takes from IV transfused cells. The amount of pulmonary tumors was not significantly altered. SC transplantability was not affected by 10 mug/ml CB. The importance of cell mobility and cell surface topography for tumor cell nidation in vessels is discussed.

Animals↗
PubMed1993

Pregnancy in chiroptera.

As with other aspects of their biology, bats exhibit considerable diversity in their reproductive characteristics. While early embryonic development in many species generally adheres to the pattern shown by more commonly studied eutherian mammals, others demonstrate advanced development in the oviduct (to the zona-free blastocyst stage) and a prolonged tubal journey of the embryo in a temporal sense. In some bats, the process for transporting ova through the oviducts can distinguish between living embryos and the remnants of dead ova. Implantation in bats is unusually diverse with respect to localization of the nidation sites (which in most species seem to be predetermined), orientation of the inner cell mass during implantation, depth of implantation, and trophoblastic invasiveness. Some species which can be bred in captivity would appear to be promising experimental models for studies of implantation because both this process and their endometrial biology in general exhibit many similarities to those of humans. Depending upon the species, bats develop either endotheliochorial or hemochorial placentas. Studies on black mastiff bats (Molossus ater) indicate that maternal endometrial endothelial cells probably play a very important morphogenetic role during placental development in this species. Similarities in placental structure suggest that this may also be the case in a number of other eutherian mammals.

Animals↗
PubMed1990

Immunohistochemical localization of prostaglandin H synthase in the embryo and uterus of the mouse from ovulation through implantation.

Prostaglandins (PGs) in the embryo and endometrium are involved in processes that are important for implantation. Although the presence of PGs (PGE2, PGF2 alpha, PGI2) in decidualized endometrium has been widely reported, less is known about the capacity of the pre-implantation embryo to synthesize PGs. Prostaglandin H (PGH) synthase is necessary for the production of PGs. Using an immunohistochemical method, PGH synthase was localized in the mouse embryo and uterus from superovulation through embryo implantation. No PGH synthase was detected in oocytes at the time of ovulation or in single-cell embryos 1 day post-fertilization (PF). Circular areas of immunostaining became evident in the cytoplasm of blastomeres at the morula stage (day 3 PF). After implantation (day 5 PF), a low level of PGH synthase reactivity was observed in embryonic cells; no PGH synthase was detected in the embryo by day 7 PF. The endometrial glands exhibited maximal immunostaining by day 3 PF, and after implantation, PGH synthase appeared in decidual cells along the border of placentation. Low levels of PGH synthase reactivity were detected in myometrial cells during the period after superovulation through day 7 PF. This is the first demonstration of PGH synthase in the mouse embryo prior to apposition with glandular endometrial epithelium, supporting the hypothesis that the embryo has the potential to produce PGs that may mediate autocrine and/or paracrine responses at the time of nidation.

Animals↗
PubMed1982

Mononuclear phagocytes in the control of primary and secondary tumor growth.

In a variety of defined experimental host/tumor situations there is now considerable evidence that mononuclear phagocytes are critically involved in the control of tumor cell nidation and their establishment as primary tumors. The factors which determine secondary tumor cell spread and the establishment of metastases are clearly complex and make it highly unlikely that tumor cell dissemination is under the control of a single host defense mechanism. Nonetheless, findings in various experimental models suggest a critical role for mononuclear phagocytes in the surveillance of tumor cell dissemination.

Animals↗
PubMed1995

Superfetation occurring in connection with gamete intrafallopian transfer: a case report.

This observation reports a case of susperfetation which occurred in connection with gamete intrafallopian transfer (GIFT). The macroscopic and histological examination of a spontaneous abortion from a 33-year-old woman (15th week of pregnancy) revealed the existence of two embryos with a monochorionic diamniotic placenta (developmental age approximately 41 days) and two fetuses and a fetal remnant with a trichorionic and triamniotic placenta (developmental age approximately 98 days). The large developmental age difference of embryos and fetuses cannot be explained by retardation, because the embryos showed adequate development with the development of their placenta. Moreover, the usual causes of intrauterine growth retardation could be excluded as could retention of the embryos since the tissues showed no autolytic changes. Consequently the large developmental age difference is explained by assuming that the embryos developed from successive ovulations. A second nidation of blastocysts had occurred after the GIFT concurrently with the clinically reported hyperstimulation syndrome.

Abortion, Spontaneous↗
PubMed1986

Radioiodinated surface proteins of rabbit trophectoderm cells.

We have previously used surface iodination to discriminate between the protein patterns of epithelial cell surfaces in uteri of rabbits receptive (Day 6.5) or nonreceptive (Day 4) to nidation (Ricketts et al. 1984). In this paper, we describe application of the same technique to the trophoblastic surface of rabbit blastocysts collected on the same days of pregnancy. Analysis of labelled proteins by polyacrylamide-gel electrophoresis under denaturing conditions did not reveal qualitative differences between the two days of pregnancy. Scanning densitometry was used to quantitate the area under each protein peak on an autoradiogram; these areas were used as variables in statistical analysis of the protein pattern of individual animals. Quantitative differences between the protein patterns of the two surfaces were detected by canonical variate analysis of the pattern of relative areas of labelled protein peaks. In proteins separated on 7.5% gels, this statistical analysis correctly assigned blastocysts from 8 out of 10 animals to one of two groups according to day of pregnancy. The discrimination was not statistically significant, however, in protein patterns on 12.5% gels, used to give better separation in the lower range of molecular weights. The same analysis in the uterus unequivocally separated the surface iodination patterns from these same days of pregnancy. Thus the changes detected by surface iodination appear to be less pronounced on the trophectoderm than on the uterine epithelium in relation to the time of ovoimplantation.

Animals↗
PubMed1976

[Legal abortion and hemostasis. Histological examinations and comparison to post partum hemostasis (author's transl)].

30 women were examined to determine the hemostasis during the legally induced abortion. The blood coagulated in the intervillous spaces while the fetus is removed. Immediately after the termination of the curettment the nidation area is covered by filaments of fibrin and incorporated erythrocytes. More frequent as post partum platelet thrombi occur especially in the area of decidua parietalis. The intravascular findings are similar to post partum changes after the removal of the placenta. Obstruction clots of the spiral arterioles contain fibrin deposits, pletelet thrombi and erythrocytes (mixed form of thrombi). Residual decidua and trophoblast cells are seldom involved in the obturation of the vessels. The traumatic damages of the uterine wall are described (extravascular fibrin deposits, interstitial bleeding, succulent tissue a.s.o.).

Abortion, Legal↗
PubMed1986

Adrenoceptor modulated flow through the rabbit ampulloisthmic region studied in vivo and in vitro.

In adult rabbit does ovulation was induced by human choriongonadotropin (hCG) 48 hours before experiments. At laparotomy the oviducts were cannulated from the ovarian and uterine ends. In vivo as well as in vitro the patency of the isthmus was studied with low viscous fluid perfusion of the ampulloisthmic region in antegrade direction. Intraluminally applied norepinephrine (NE) or phenylephrine (PhE) caused dual changes in transisthmic flow; administration of a low dose increased the flow, while high doses decreased the flow in vivo. In vitro, application of PhE only induced a dose-dependent reduction of flow. The PhE-induced reduction of flow was prevented by pretreatment with phenoxybenzamine in vivo and in vitro, suggesting activation of an alpha-adrenoceptor mechanism. Intraluminal application of terbutaline (T) caused a dose-dependent increase of flow, which was most prominent in vivo. Such an increase of flow was prevented by blockade of beta-adrenoceptors with propranolol or by selective blockade of beta 2-adrenoceptors with IPS 399 both in vivo and in vitro, indicating activation of a beta 2-adrenoceptor mechanism. The biochemical and hormonal changes 48 hours after ovulation imply a role for the sympathetic transmitter NE in causing a contractile state of the ampulloisthmic region ("tube locking") for retention of ova prior to nidation in the uterine cavity. The isthmus would then hypothetically act as a sympathetically innervated smooth muscle sphincter. The present results demonstrate a constrictory response of this region to high-dose stimulation of alpha-adrenoceptors in support of such a hypothesis. However, it must be noted that this region also possesses a population of beta-adrenoceptors at this time interval, which may interfere with a constrictor mechanism via circulating epinephrine.

Animals↗
PubMed1996

The in vitro development of mouse embryos beyond the blastocyst stage into the hatching and outgrowth stage using different energy sources.

PURPOSE: The purpose of this study was to investigate the effect of male and female serum supplementation on the in vitro development of mouse embryos beyond the blastocyst stage until the outgrowth stage since the latter may be related to the nidation of the embryo. We also studied the effect of EGF addition on embryo culture and blastocyst outgrowth. METHODS AND RESULTS: The blastocyst and hatching rates of two-cell mouse embryos cultured in Ham's F-10 + BSA, Ham's F-10 + male serum, or Ham's F-10 + female serum were found to be comparable (P > 0.05). The outgrowth rate of hatched blastocysts was significantly increased, though, when they were transferred to 50% male serum compared to either 50% BSA or 50% female serum (P < 0.01 and P < 0.05, respectively). In the last experiment, either 100 or 150 ng/ml EGF was added to the culture medium from the two-cell stage till blastocyst development and the latter were cultured till outgrowth in 50% BSA, male serum, or female serum. For both concentrations of EGF, the outgrowth rate was significantly higher in male serum compared to the other conditions (P < 0.01 and P < 0.05, respectively). The outgrowth rate was also higher when EGF was used compared to plain medium before transferring the blastocysts to either male or female serum (P < 0.01 for both). CONCLUSIONS: We conclude that the development of embryos to the outgrowth stage is significantly enhanced by male serum. The addition of EGF from the two-cell stage also significantly improves the outgrowth success rate for both male and female serum conditions.

Animals↗
PubMed1977

[Investigation of pregnancy hypertension as a consequence of utero-placentar ischemia (author's transl)].

An attempt at provoking gestosis by constricting the uterine artery was made using pregnant rats and rabbits. The experiment failed. Reducing the circulation by means of Z-sutures in the region of the nidation site failed to produce symptoms of gestosis also. The result of the uterine manipulations was abortion and intra-uterine retardation of the product of conception. Though it was not possible to verify the pathogenesis of gestosis due to impaired circulation of the uterus. On the basis of these experiments previous gestosis hypotheses stemming from animal experiments cannot be questioned. However, it is though-provoking that a review of the literature reveals that the results of these "classical model experiments" cannot always be interpreted uniformly.

Animals↗
PubMed1975

Failure of stressful stimuli to inhibit embryo implantation in the rat.

The effects of stess by extreme temperature or immobilization on rat embryo implantation were investigated. One group of rats remained at 4 degrees C. at different days of progravidity. Other rats on L-3 of pregnancy remained at 39 degrees C. or immobilized. All the animals were put to death on L-6. The stressors produced no changes in either the per cent of rats implanting, the number of corpora lutea and implantation sites, or the weight of the ovaries and uteri. These results suggest that the process of nidation in the rat is resistant to several noxious environmental conditions.

Animals↗
PubMed1986

Experimental evidence for failure to implant as a mechanism of infertility associated with endometriosis.

The effect of endometriosis on pregnancy, from ovulation through day 14 of pregnancy, was studied in an animal model previously developed and validated with the use of the rabbit. Endometrial tissue was implanted surgically in rabbits and allowed to grow for 11 weeks without hormonal supplementation. The animals were artificially inseminated with semen from bucks with established fertility and human chorionic gonadotropin was administered to induce ovulation. The animals were put to death 1, 4, 8, or 14 days later. The number of corpora lutea and fertilized ova was not affected through day 4. However, on days 8 and 14, a significant reduction in the number of normal fetuses was observed. In a second experiment peritoneal fluid from animals with endometriosis was transferred to normal rabbits 1 day before artificial insemination. A significant reduction in the number of normal fetuses was observed. These studies suggest that failure of nidation due to the maternal environment may be a major factor in infertility associated with endometriosis.

Animals↗
PubMed1986

A comparison of three techniques for ovarian reconstruction.

We compared three methods of ovarian reconstruction in 23 mature female New Zealand White rabbits. Each animal was its own control. The right ovary in each rabbit was incised and repaired by placing three 8-0 nylon sutures through and through the base of the defect (method A). The left ovary was repaired without these through-and-through sutures. In 16, hemostasis was achieved by microbipolar cautery (method B); in seven, hemostasis was achieved with three sutures placed entirely inside the defect (method B1). The cortex of each ovary was repaired identically by continuous 8-0 nylon suture. Outcome was evaluated by laparoscopy 14 days after mating. Through-and-through sutures (right ovary) caused a significant increase in adhesion formation and decrease in nidation index. When these animals were put to death 14 weeks later, the right ovaries were significantly smaller. On the left, there was no difference in any outcome variable between methods B and B1. This study clearly shows the detrimental effect of through-and-through sutures for ovarian reconstruction.

Animals↗
PubMed1977

Studies of the growth and infiltration of experimental tumor of the pancreas in rabbits.

An experimentally transplanted pancreatic cancer was induced by means of an intraductal injection of Vx2 carcinoma supernatant into the pancreatic duct of rabbits. The presence of ductal obstruction appeared to assist the nidation and growth of injected cancer cells in the pancreas. Tumors induced in the head of the pancreas grew by extension to the body and tail where they also produced interspersed, nodular tumor masses. Tumors induced in the body and tail region, on the other hand, grew by direct expansion towards the head, but this did not produce the interspersed nodular tumors in the head portion. These observations indicate that cancer of the head of the pancreas associated with the stenosis or obstruction of the pancreatic duct resulted in ductal dissemination and extensive lymphatic infiltration in the body and tail, a wider cancer invasion than recognizable at the gross cancer border. This extension was noncontinuous and interspersed, so that radical curative surgery for such cancer of the head of the pancreas would indicate total pancreatectomy.

Animals↗
PubMed1984

Biological, microscopic and scanning electron microscopic investigations of the effects of postinor /d-norgestrel/ in rabbits.

The contraceptive effect of d-norgestrel given immediately after copulation in various quantities was investigated in rabbits. It was established that the effect is dose-dependent. A correlation was found between the amount of dose administered and the changes taking place on the surface of endometrium. It can be suggested that d-norgestrel alters the surface of the endometrium to such an extent that nidation is unable to take place; therefore, it can be used for postcoital contraception at any time.

Animals↗
PubMed1989

3H-ZK 98,734, a new 11 beta-aryl substituted antigestagen: binding characteristics to receptor and serum proteins.

Recently, in the laboratories of Schering in Germany a competitive progesterone antagonist, ZK 98,734, was synthetized, which is characterized by a similar antigestagenic activity as RU 38,486, synthezised by Roussel-Uclaf in France, as assessed by inhibition of nidation tests in rats and guinea pigs. However, this compound has a substantially lower antiglucocorticoid activity measured in cell culture systems than RU 38,486. The purpose of this study was to present a comparison of biochemical and physical properties of the complexes formed by the human uterine progesterone receptor with 3H-ZK 98,734 on one hand and with other well-established progestins on the other hand. ZK 98,734 competed in the same order of magnitude as progesterone or RU 38,486 for the 3H-R5020 binding site of progestin receptor, whereas R5020, Org 2058 or progesterone were unable to compete against 3H-ZK 98,734. This apparent contradiction could be explained by means of FPLC-chromatography and sucrose density centrifugation technique. FPLC-chromatography with an anion exchange column (Mono Q, Pharmacia, Uppsala, Sweden) showed that 3H-ZK 98,734 forms at least two stable complexes with uterine cytosol, on one hand with serum albumin, which presents almost 90% of bound radioactivity, and on the other hand with the two native progestin receptor forms, corresponding to 4S and 8S receptor forms in sucrose density gradient analysis. Competition experiments in liver cytosol of adrenalectomized rats with increasing concentrations of unlabeled ligands other than dexamethasone showed that ZK 98,734, RU 38,486 and cortisol displaced 3H-dexamethasone efficiently from the binding sites in the cytosol. Furthermore, results concerning the specificity of 3H-cortisol binding to serum proteins in diluted pregnant serum demonstrated that ZK 98,734 did not compete with 3H-cortisol for serum binding.

Animals↗
PubMed1994

Expression of a 10.5 kDa inhibin in the endometrium of bonnet monkey on treatment with an antiprogestin ZK 98.299: an immunocytochemical study.

Immunocytochemical localization of inhibin was carried out in paraffin embedded tissue sections of the control and antiprogestin (ZK 98.299)-treated bonnet monkey endometrium using polyclonal antibodies generated against human seminal plasma inhibin (10.5 kDa). The study shows that administration of low doses (5 mg/week) of antiprogestin results in an increase in the expression of inhibin by the endometrium. Treatment with higher doses (20 mg/week) caused a decrease in the expression. Since treatment with higher doses also caused atropic changes in the endometrium, the decrease in inhibin could be the result of morphological damage to the endometrium rather than the effects of antiprogestin on the expression of inhibin. The potential involvement of endometrial inhibin in the process of nidation is speculated.

Animals↗
PubMed1989

Effect of human chorionic gonadotropin and prostaglandin F2a on progesterone production by human luteal cells.

To determine and compare the direct effects of prostaglandin F2a (PGF2a) and human chorionic gonadotropin (hCG) on luteal cell progesterone production in vitro, 9 human corpora lutea obtained at tubal ligation were minced and treated with collagenase to disaggregate luteal cells. Dispersed luteal cells (80% viable) were incubated in air at 37 degrees C in a shaking water bath for 3 h and total progesterone in the media and cells was determined by radioimmunoassay. Optimum progesterone production was obtained using 25,000 or more cells per incubate and an incubation time of 2-4 h. hCG-stimulated progesterone production increased significantly with 0.01 IU to as high as 100 IU. In the early luteal phase (days 1-5 post ovulation or days 15-20 of the luteal phase), PGF2a (10-1000 ng) significantly inhibited progesterone production but significantly stimulated progesterone production in the mid-luteal phase (days 21-25). PGF2a had no effect on luteal cell progesterone production in the late luteal phase (days 26-30). This age-dependent direct effect of PGF2a on human luteal cell progesterone production in vitro indicates a role for PGF2a in the total intragonadal regulation of progesterone output, possibly through a paracrine or autocrine manner directed towards synchronizing luteal progesterone secretion and endometrial preparation for nidation.

Chorionic Gonadotropin↗