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At least 217 records · Page 12Linked to original sources
PubMed1982

[Inhibition of nidation in mice by modification of the environment and pheromones. Re-establishment by prolactin and thioproperazine].

325 mated mice (evidence of a vaginal plug, J1) were divided into 8 groups, 246 were subjected to various kinds of stress before day 7 of gestation: 120 were placed singly in boxes and/or transferred to different ones: 75 were exposed to alien males with or without box transfer. 85% of the 50 unstressed females did, in fact, become pregnant. Isolation by itself did not modify the course of gestation. Transfer to a new box (74 females) along with isolation from days, 1, 2, 3 or 4 on reduced the percentage of pregnant females to 55%. Exposure to a strange male in the common box of females (26 females) reduced it to 55%. Isolation of a single female with a strange male, along with transfer (49 females; Bruce Effect) on day 4, 5 or 6 reduced this percentage to 25, 6 or 20% respectively. In addition when the stress occurred on day 4 the number of implantations was greatly reduced. A daily s. c. injection of B prolactin or of thioproperazine on days 4, 5 and 6 prevented the onset of the pregnancy block (47 females). If the 325 mice are separated into 2 groups, those ind whom gestation was maintained and those who aborted, ponderal growth greatly increased in the former; their adrenal glands weighed less, and their preputial glands weighed more. An excessive secretion of corticosteroids in non-pregnant females could be the cause of the inhibition of prolactin release. These results suggest that the effects and probably the implicated mechanisms are the same for pheromones and environmental changes as prolactin and thioproperazine prevent the effects in both cases. The variation in the susceptibility of mice could be due to genetic factors that play a primary role in hypophyso-adrenal response to emotional stress.

Animals↗
PubMed1984

[Endometrial steroid receptor during normal menstrual cycle and physiopathology of nidation].

Human uterine endometrial steroid receptor [estrogen (ER), progestin (PR) and androgen (AR) receptors] in the normal menstrual cycle were determined at the cellular level. Endometria with pathological out-of-phase findings or with hypoplastic uterus were evaluated for the concentration of steroid receptors, for a better understanding of their pathophysiology. ER and PR levels gradually rose toward the early secretory phase, remained at the maximum level during the mid-secretory phase and dropped to the lowest level during the late secretory phase. Especially nuclear PR reached the maximum level during the mid-secretory phase. These results indicate that the endometrial ER and PR, especially the endometrial nuclear PR, is kept in the maximum level at implantation. AR showed only a slight change in a very low level throughout the menstrual cycle. This indicates that androgen may not play so important a role in endometrial physiology. Endometria with out-of-phase or with hypoplastic uterus contained significantly low levels of endometrial ER and PR, while serum hormones levels were normal. This indicates indigenous reduction of ER and PR synthesis in such endometria.

Cytosol↗
PubMed1983

[Correlation between the movement of trophoblast cells invading the implantation site and the microfilament system--with special reference to the nidation site on day 15 post-coitus].

Trophoblast cells invading into decidual tissue of implantation sites of 21 cases in early stage of gestation were morphologically studied in order to clarify the correlation between integrity of the microfilament system and the various biological statuses. Especially, trophoblast cells of ovum at 15 day post coitus were mainly analyzed, since the migrating direction of the cells could be easily identified. 1. Syncytiotrophoblast cells migrating to maternal vessel were in slender shape toward the vessel. Thin and thick filaments connecting to dense body in tip of the cell run parallel with the cell axis. Thus, it is suggested that trophoblast cell migrates in decidual tissue by the joint work of its own actin and myosin in the tip of the cell. 2. Trophoblast cells making close contact with maternal cell such as endothelial cell, decidual cell and gland cell were relatively stable. The cells mainly put into action to project the cytoplasmic processes by thin filament, beneath the cytomembrane, running parallel with the cytomembrane and by thin filament, in the cytoplasmic process, running parallel with the axis of the cytoplasmic process in order to exchange information with maternal cell or to destroy the maternal cell.

Cell Movement↗
PubMed1984

[Detection of early pregnancy factor in the sera of conceived women before nidation].

In order to apply the early pregnancy factor (EPF) to early diagnosis of fertilization, the establishment of optimal conditions for assay of EPF was attempted, and then EPF in the sera of contracepted and conceived women 4 to 6 days after ovulation were measured. For assay of EPF, 0.25 ml of 1:2 step diluted anti-human lymphocyte serum (ALS), 0.05ml of guinea pig serum as complement and 0.1ml of lymphocytes suspension (1 X 10(7)/ml) pretreated with test serum were mixed and then incubated at 37 degrees C for 90 min. To this mixture 0.1ml of sheep red blood cell suspension (2 X 10(9)/ml) was added and the rosette formation was counted after centrifugation. The rosette inhibition titer (RIT) was expressed as reciprocal of ALS dilutions which resulted in less than 75% of rosette formation as compared with the control. RITs of the conceived women who were assayed on the 5 th day after ovulation were in the range from 16 to 32 X 10(3), while that of the control contraceptive women who were assayed on the same day was in the range from 2 to 4 X 10(3). The sterile women who received AIH but failed to conceive all showed less than 4 X 10(3) as RIT. These results suggest that the assay of EPF is valuable in detecting the early stage of fertilization and possibly may help to differentiate the impairment of embryo implantation from non-fertilization of the ovum as a cause of sterility.

Chaperonin 10↗
PubMed1994

[Anti-nidation activity of oral contraceptives].

The antinidatory activity of the oral contraception is generally unknown: the contraceptive pill mainly prevents the gametes from meeting. However, pregnancies under pill indicate conception of embryos. Besides, missed pills protocols sometimes record ovulatory escape. We suggest the computation of an Embryo Destruction Index (EDI), in order to measure the antinidatory effect of two categories of oral contraceptives: combined estroprogestatives and microprogestatives.

Contraceptives, Oral, Combined↗
PubMed1978

[Studies on the biological action of uterine RNA in rat implantation (author's transl)].

With a view to investigating the mechanism of the action of estrogen involved in nidation, the biologically active rat uterine RNA thereby derived was extracted and then administered in the uterine cavity of castrated rats to observe the ensuing morphological changes in the endometrium and compare them with those resulting from the administration of decidual RNA which is non-estrogenised. There was a tendency toward increasing proliferation noted in the endometrial epithelium of the castrated rats 48 hours after the administration of the biologically active uterine RNA, as in the endometrial epithelium of animals receiving estradiol-17beta. There was also an increase in the number of 3H-thymidine-labelled cells present in the endometrial epithelium of animals so treated. On the other hand, no such changes were observed following the administration of the RNA pretreated with RNase. In the case of castrated rats administered with the RNA in the uterine cavity under progesterone priming, the endometrial epithelium as the site of increase in the number of the radio-labelled cells at 24 hours was found to be superseded by the stromal cells at 48 hours. A similar phenomenon of transfer was seen with regard to the site of an increase in the mitosis index caused by pretreatment with colchicine. An observation of the endometrium of castrated rats 72 hours after the administration of decidual RNA disclosed that the stroma was mildly edematous with the stromal cells somewhat swollen, but without any such changes in the endometrial epithelium as seen following the administration of the biologically active uterine RNA. These findings led us to administer such biologically active substances as uterine RNA, decidual high molecular RNA, human chorionic RNA, rat placental RNA (L15) and early pregnant rat uterine RNA (L4) separately in the uterine cavity of delayed implantation rats to determine whether any one or more of these RNAs had a nidation promoting effect just like estrogen. As a result, nidation was found to be induced in animals administered with 1 approximately 100 microgram of the biologically active uterine RNA or 100 microgram of early pregnant rat uterine RNA. No nidation was provoked by other specimens of RNA. A study was then made of blastocysts recovered by the flush-out technique from the uterus of animals receiving 1 approximately 10microgram of human chorionic RNA or 10microgram of rat placental RNA, which failed to induce nidation. It was shown that these blastocysts were dormant morphologically. From these results it is apparent that both biologically active uterine RNA and early pregnant rat uterine RNA are effective in promoting nidation. It is also suggested that, in the process of implantation of fertilized eggs, nidatory estrogen may first promote RNA synthesis in the endometrium and then exhibit its action through the medium of RNA thus synthesized.

Animals↗
PubMed1978

The ovoimplantation of Microcebus murinus Miller. (Primates, Lemoruoidea, Strepsirhini).

The process of nidation of Microcebus murinus may be subdivided into several stages (preadhesion, apposition, attachment and invasion), as is indicated for protracted phases of preimplantation. Not until the apposition stage does the inner cell mass orient itself orthomesometrially, while concurrently a nidation plaque develops in the abembryonal trophoblast that overlies and resorbs the coalescent glands. During the subsequent adhesion stage, the paraembryonal, bilaminar omphalochorion becomes attached to the uterine epithelium, with focal resorption of the latter. In addition, chorionic vesicles begin to develop. In the meantime, the embryonic disc has lost its trophoblastic cover as a preliminary to the formation of the pleuramnion. The formation of a nidation plaque, together with the subsequent central implantation of Microcebus, suggests a close relationship to Loris tardigradus, characterizing the mode of implantation of Strepsirhini. The nidation plaque and its invasive capacity, giving rise to a syndesmochorial placental nucleus, provide a placentological link to Galago demidovii.

Animals↗
PubMed1975

Ultrastructural changes in granulosa lutein cells and progesterone levels during preimplantation, implatation, and early placentation in the western spotted skunk.

The ultrastructure of corpora lutea obtained during the preimplantation implantation and early post-implantation periods has been studied in 20 western spotted skunks. Fine structure of granulosa lutein cells was correlated with progesterone levels. The corpus luteum of the prolonged (7 month) preimplantaion period contained undifferentiated small granulosa cells and differentiated large granulosa lutein cells. The former ranged in size between 12 and 20 mu and the latter between 20 and 45 mu. The ratio of small and large cells was about equal in an animal 2 days prior to nidation whereas only few small cells and numerous large cells were observed in an animal estimated to be 8 to 12 hours from nidation. Occasionally small cells were observed amidst large ones during the 24 hour nidation period, i.e. adhesion of trophoblast with the luminal uterine epithelium, but small cells were absent in animals after this period. Small cells had some smooth and rough endoplasmic reticulum rod-shaped mitochondria with plate-like cristae, small Golgi complex, and relatively smooth plasma membranes. Large lutein cells had abundant smooth endoplasmic reticulum, membranous whorls of smooth endoplasmic reticulum, usually round mitochondria with tubular and lamellar cristae, a well developed Golgi complex, variable amounts of lipid droplets, and highly plicated and ruffled plasma membranes. Peripheral plasma progesterone levels during the prolonged preimplantation period ranged between 1.1 and 7.9 ng/ml, but during implantation it was between 8 and 16.6 ng/ml. It is suggested that plasma progesterone levels fluctuate during the time of implantation and should not be regarded as a basis to predict actual nidation in the western spotted skunk.

Animals↗