The allantoic and amniotic epithelia of the pig: SEM and TEM studies

Tiedemann, K.

doi:10.1007/bf00315715

Cited by 14 publications

(18 citation statements)

References 25 publications

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“…The characteristics of the allantois are similar to those in swine (Tiedemann 1979), but, according to our observations, the allantois cells appear to have a secreting function in llamas, denoted by the villous surface. We believe that the differentiated cells found on the surface reveal a functional specialization of the allantois.…”

Section: Discus Discus Discus Discus Discussion Sion Sion Sion Sionsupporting

confidence: 76%

The materno-fetal interface in llama (Lama guanicoe glama)

et al. 2007

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Samples from 9 llamas (28 through 36 weeks of gestation) were collected and fixed in 4% buffered paraformaldehyde (light microscopy) and in 2.5% buffered glutaraldehyde (transmission and scanning electron microscopy). The material was processed in paraplast and slides (5mm) were stained with HE, PAS, Masson-Trichrome, acid phosphatase and Perl's. The uteroferrin was immunolocalized. The results show that llama placenta is chorioallantoic, diffuse, folded and epitheliochorial, and the fetus is covered with an epidermal membrane. The trophoblast cells have variable morphology: cubic, rounded and triangular cells, with cytoplasm containing PAS-positive granules. Binucleated cells with large cytoplasm and rounded nuclei, as well as giant trophoblastic cells with multiple nuclei were also observed. Numerous blood vessels were observed beneath the cells of the uterine epithelium and around the chorionic subdivided branches. Glandular activity was shown by PAS, Perl's, and acid phosphatase positive reactions in the cytoplasm and glandular lumen, and by immunolocalization of the uteroferrin in the glandular epithelium. The uterine glands open in spaces formed by the areoles, which are filled by PAS-positive material. The llama fetus was covered by the epidermal membrane, composed of stratified epithelium, with up to seven layers of mono-, bi- or trinucleated cells. The high level of maternal and fetal vascularization surfaces indicates an intense exchange of substances across both surfaces. The metabolic activity shown in the uterine glands suggests an adaptation of the gestation to the high altitudes of the natural habitat of this species.

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Section: Discus Discus Discus Discus Discussion Sion Sion Sion Sionsupporting

confidence: 76%

The materno-fetal interface in llama (Lama guanicoe glama)

et al. 2007

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“…In the opossum, the allantois remains free within the extraembryonic coelom and does not form a n association either with the yolk sac placenta or the amnion. This feature is quite unlike the events reported in most eutherians (Petry, 1959;Zobundzija, 1968;Tiedemann, 1979aTiedemann, ,b, 1982 and some metatherian species such as the bandicoots (Tyndale-Biscoe, 1975;Taylor, 1976, 1977).…”

Section: Discussioncontrasting

confidence: 45%

“…The occasional mitotic activity in the allantoic epithelium provides cells for replacement or growth of this epithelial layer. The dark cells in the allantoic epithelium of Didelphis are quite unlike those reported in the rabbit (Kuhnel, 1965) or cattle (Tiedemann, 1982) where the dark forms appear to be a distinct cell type within the allantoic epithelium. In other eutherian species such as the cat (Tiedemann, 1979b), the allantoic cells contain abundant glycogen and the luminal plasmalemma is modified to form large, branching apical outgrowths.…”

Section: Discussionmentioning

confidence: 47%

“…In other eutherian species such as the cat (Tiedemann, 1979b), the allantoic cells contain abundant glycogen and the luminal plasmalemma is modified to form large, branching apical outgrowths. The allantoic epithelium in the pig is thought to have secretory activity and differs considerably from that of other mammals (Tiedemann, 1979a) in that two markedly different cell types-mitochondriarich cells and granular cells that contain numerous secretory granules-are present. From scanning electron microscopy, the luminal surface of the allantoic epithelium of the species examined thus far is species specific and two or more individual cell types can be identified by surface features alone (Tiedemann, 1979a(Tiedemann, ,b, 1982.…”

Section: Discussionmentioning

confidence: 98%

“…In many eutherian mammals, particularly carnivores and ungulates, the allantois rivals that of birds and forms a large conspicuous sac that stores urinary wastes (Arey, 1962;Zobundzija, 1968;Tiedemann, 1979aTiedemann, ,b, 1982. Regions of the allantois in these species also may fuse with areas of the amnion and chorion later in fetal life.…”

mentioning

confidence: 99%

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The allantois of the north american opossum (didelphis virginiana) with preliminary observations on the yolk sac endoderm and trophectoderm

Krause

Cutts

1985

Anat. Rec.

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During the middle of prenatal day 10, the opossum allantois forms as a ventral outgrowth of the hindgut. By day 11 it appears as a large, fluid filled sac and by the middle of day 12 (just prior to birth) it reaches its maximal development. The simple squamous epithelium lining the allantois consists of only one cell type that often contains numerous filaments in the apical cytoplasm. At the luminal surface, the apices of the cells are united by junctional complexes and desmosomes are present between adjacent cells. The luminal surface is irregular, whereas laterally and basally the cell membranes show few if any infoldings. Mitotic figures and presumptive degenerating cells occasionally occur in the allantoic epithelium which rests on a delicate basal lamina. The allantois is covered by a simple squamous mesothelium that lacks a distinct basal lamina. Between the two epithelial sheets lie mesenchymal cells, collagen fibers, and blood vessels. No specializations of cell membranes were noted in either of the epithelial layers. The yolk sac endoderm consists of a single layer of squamous cells whose cytoplasm contains scattered profiles of rough endoplasmic reticulum and mitochondria. Extensive lateral and basal infoldings of the plasmalemma were not observed in these endodermal cells. The morphology of the trophectodermal (trophoblastic) cells indicates a cell type that is active in the transport of materials. Since the endodermal cells that line the allantois lack morphological features that would suggest the presence of mechanisms for transport or exchange, and because they remain relatively unchanged throughout pregnancy, it is thought that the allantois functions primarily in the storage of urinary wastes during prenatal life.(ABSTRACT TRUNCATED AT 250 WORDS)

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Gestational changes in electrolyte transport, electrical activity, and permeability of the porcine placenta

Rice

Dantzer²,

Madsen

et al. 1991

J Comp Physiol B

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1. The electrolyte transport capacities of the porcine placenta and fetal membranes (amnion, chorion, and allantois) during gestation (47-112 days) were assessed in vitro and in the absence of electrochemical, osmotic, or hydrostatic driving forces. Net transmural transport of 22Na and 36Cl across sections of porcine allantochorion-endometrium (ALCE), amniochorion-endometrium (AMCE), and allantoamnion (AA) mounted in Ussing chambers could not be detected at any stage of gestation. 2. These tissues were characterised throughout gestation by low electrical potential difference (PD; less than 5 mV, fetal side positive with respect to maternal side) and short circuit current (SCC; less than 16 microA.cm-2) which were amiloride and iodoacetate sensitive. 3. A periparturitent reversal in the polarity of PD to fetal side negative and a change in the direction of the SCC was observed in tissues obtained from sows (n = 3) at 111-112 day gestation. These changes were accompanied by a 73% increase in electrical resistance (R) and a 2-10-fold decrease in the permeability of tissues to Na and Cl. 4. Morphological studies revealed a decrease in the thickness of allantoamnion and a decrease in the height of epithelia from ALCE, AMCE, and AA during gestation, indicating a decrease in activity. These morphological changes only partly explained the pre-term electrophysiological changes in these tissues.

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The allantoic and amniotic epithelia of the pig: SEM and TEM studies

Cited by 14 publications

References 25 publications

The materno-fetal interface in llama (Lama guanicoe glama)

The materno-fetal interface in llama (Lama guanicoe glama)

The allantois of the north american opossum (didelphis virginiana) with preliminary observations on the yolk sac endoderm and trophectoderm

Gestational changes in electrolyte transport, electrical activity, and permeability of the porcine placenta

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