Experimental Ectopic Implantation of Eggs and Early Embryos in Guinea-Pigs

Bland, K. P.; Donovan, B. T.

doi:10.1530/jrf.0.0100189

Cited by 20 publications

(5 citation statements)

References 16 publications

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“…Cases of secondary abdominal pregnancy have been reported in several animal species, and they have been experimentally induced in rabbits, guinea pigs (Bland & Donovan 1965), rats (Bunte & Hildebrandt 1975) and mice (Hreshchyshyn & Hreshchyshyn 1964). In humans, secondary abdominal pregnancy is usually subsequent to tubal pregnancies with a rupture of the oviduct (Smith et al 1974).…”

Section: Abdominal Pregnanciesmentioning

confidence: 99%

Ectopic pregnancy in animals and humans

Corpa¹

2006

Reproduction

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Ectopic pregnancy denotes a pregnancy occurring elsewhere than in the cavity of the uterus. This pathology has been recognised for years and it causes numerous maternal deaths during the first trimester of pregnancy. While this condition is wellknown in humans, it is rarely diagnosed in animals. However, the causes and mechanisms leading to an ectopic implantation of the ovum are not always clearly defined in humans or animals. Two types of ectopic pregnancy are mainly recognized: (1) tubal pregnancy occurs when an oocyte is fertilized and then remains in the oviduct and (2) abdominal pregnancy occurs when the gestation develops in the peritoneal cavity. The latter may be subdivided into two subtypes: the primary form, when a fertilized oocyte enters the peritoneal cavity and becomes attached to the mesentery or abdominal viscera, and the secondary form, which follows the rupture of an oviduct or the uterus after the fetus has been implanted, and the fetus is expelled into the peritoneal cavity. Cornual, ovarian and cervical ectopic locations are less frequent. Several differences exist in ectopic pregnancies between human beings and animal species. While abdominal pregnancy has been described in both human and animal species, tubal ectopic pregnancies would appear to be restricted to primates. Other than anecdotal cases, this pathological condition does not occur in laboratory, domestic or farm animals. Several factors are described as being the cause of these differences.

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Section: Abdominal Pregnanciesmentioning

confidence: 99%

Ectopic pregnancy in animals and humans

Corpa¹

2006

Reproduction

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“…On the other hand, Bland and Donovan [17] were able to induce abdominal implantation in guinea pig by introducing fertilized eggs into the peritoneal cavity. These authors found that trophoblast was produced in all cases, but the nontrophoblastic component of these implants was restricted to a mesenchyme-like tissue.…”

Section: Discussionmentioning

confidence: 99%

Development of Some Organs Derived from the Three Embryonic Germ Layer in a Degus Ectopic Pregnancy and Presence of a Cytotrophoblast That Mimics Human Chorionic Placenta

Bosco

Díaz

González

et al. 2014

Case Reports in Veterinary Medicine

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This report describes a case of abdominal pregnancy in an adult female degu from which we recovered two large tissular masses from the peritoneal cavity. The bigger one showed a number of thin vascular connections to the serosa layer of the small intestine. It was also directly connected to the smaller mass by a thin membranous process. The surface of the bigger mass facing the small intestine wall showed the presence of chorionic villous that resembled a villous human chorionic placenta, rather than the hemomonochorial labyrinthine placenta, characteristic of this species. This unusual finding leads us to postulate that in the degu's uterus the cytotrophoblast is exposed to a number of factors that will activate cascades of cellular and molecular events that ultimately will be signaling the cytotrophoblast to develop into a labyrinthine hemomonochorial placenta. In absence of the proper uterine environment, as is the case of the abdominal pregnancy in the peritoneal cavity reported here, the lack of signaling will lead the cytotrophoblast to develop into a villous chorionic placenta, similar to that observed in human.

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“…Early studies, in which blastocysts were restricted to the oviduct, all noted that they remained free within the lumen [11,[15][16][17][18], It was thought that implantation required exposure of the blastocyst to a uterine factor which was believed to initiate nidation by increasing the adhesiveness of the blastocyst through loss of the zona pcllucida [22]. Bron son and Cunnane [21], however, reported that blastocysts obtained from the uteri of donor mice on day 3.5 of pregnancy failed to implant when transferred to the oviducts of pseudopregnant mice.…”

Section: Discussionmentioning

confidence: 99%

“…To date, all attempts to produce tubal implantations by restricting the embryo to the oviduct, ligating the uterotubal junction [11,[14][15][16][17][18][19], administering exogenous estro gen [20], or transferring blastocysts to recipi ent oviducts [21] have failed. Bronson and Cunnane [21] investigated the possible effect of prior exposure of the blastocyst to the uter ine environment on tubal implantations.…”

Section: Introductionmentioning

confidence: 99%

The Fate of Trophoblast Retained within the Oviduct in the Mouse

Tutton¹,

Carr²

1984

Gynecol Obstet Invest

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Pre-implantation blastocysts or trophoblast, obtained from ectoplacental cones, were transferred to the right oviducts of both pregnant and nonpregnant mice. Blastocysts which remained within the oviductal lumen did not show evidence of further differentiation into trophoblast although they readily implanted on various extratubal sites. Similarly, trophoblast from ectoplacental cones failed to show invasive properties when restricted to the lumen. In 3 cases where trophoblast giant cells were found within the tubal lumen, entry appeared to have been contingent on an existing breach in the epithelium. Invasive action on tubal epithelium by trophoblast was not seen.

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Experimental Ectopic Implantation of Eggs and Early Embryos in Guinea-Pigs

Cited by 20 publications

References 16 publications

Ectopic pregnancy in animals and humans

Ectopic pregnancy in animals and humans

Development of Some Organs Derived from the Three Embryonic Germ Layer in a Degus Ectopic Pregnancy and Presence of a Cytotrophoblast That Mimics Human Chorionic Placenta

The Fate of Trophoblast Retained within the Oviduct in the Mouse

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