- Anatomicohistological characteristics of the tubular genital organs of the female red brocket deer (Mazama americana) in the Peruvian Amazon. [Journal Article]
- AHAnat Histol Embryol 2012; 41(6):436-44
- This study examined the anatomical and histological characteristics of tubular genital organs of 51 adult female red brocket deer in the wild in different reproductive stages, collected by rural hunt…
This study examined the anatomical and histological characteristics of tubular genital organs of 51 adult female red brocket deer in the wild in different reproductive stages, collected by rural hunters in the north-eastern Peruvian Amazon. The infundibulum was characterized by a large diameter and the presence of a highly folded and ciliated epithelium, and the isthmus has a growing secretor epithelium and a thicker muscular layer. Whereas ciliated cells are more frequent in the infundibulum, epithelial secretory cells showing abundant apical secretory blebs are more frequent in the isthmus. In non-pregnant females in luteal phase, the endometrium transforms from a proliferative to a secretory type, showing a significant proliferation of endometrial uterine glands. The red brocket deer has four large circular folds in the cervix. The epithelium of the cervix is composed primarily of secretory cells. In pregnant females, the lumen of the endocervical canal is occupied by abundant mucous secretion. All pregnant females had one embryo or fetus, with a fetal sex ratio of 54.0% females to 46.0% males. This species has a cotyledonary, syndesmochorial and partially deciduate placenta, with 6-7 dome-shaped caruncles per female. The red brocket deer does not present a true cornification of the vaginal epithelial cells, and no vaginal epithelial pattern was determined according the reproductive state of the female.
- Hysterotomy and evacuation of a deciduate placental hematoma following placental abruption. [Case Reports]
- IJInt J Gynaecol Obstet 2010; 111(1):83-4
- Macroscopic and microscopic aspects of collared peccary and white-lipped peccary placenta. [Journal Article]
- PPlacenta 2006 Feb-Mar; 27(2-3):244-57
- This study examines middle and late gestational placentae from 13 Tayassu tajacu (collared peccary) and 3 Tayassu pecari (white-lipped peccary), which are Artiodactyla belonging to the Family Tayassu…
This study examines middle and late gestational placentae from 13 Tayassu tajacu (collared peccary) and 3 Tayassu pecari (white-lipped peccary), which are Artiodactyla belonging to the Family Tayassuidae. The chorionic sac of Tayassu species is diffuse and chorioallantoic. These epitheliochorial placentae show no trophoblast invasion into the uterine epithelium and there is interdigitation between fetal and maternal microvilli. Two distinct regions of the fetomaternal interface can be identified: the interareolar and the areolar regions. The uterine epithelium has eosinophilic cytoplasm with dispersed, basophilic and electron-dense granules. Trophoblast cells are irregularly cuboidal on top of the fetal ridges and columnar on troughs, where cells have cytoplasmic vesicles and large basal vacuoles, surrounded by whorls of smooth membranes. Capillaries indent the trophoblast cells forming a placental barrier 3 microm or less thick. The columnar uterine glandular epithelium has a subpopulation of granules staining with Perl's Prussian blue reaction, suggesting iron secretion. In areolar areas, the trophoblast cells show apical microvilli, a basophilic cytoplasm with electron-dense intracellular vacuoles and cisternae. The placenta can therefore be classified as non-deciduate. The ultrastructural aspects of this study reveal features that have not previously been described and extend our knowledge of functions relating to materno-fetal transport in these species.
- Spatial and temporal patterns of expression of messenger RNA for insulin-like growth factors and their binding proteins in the placenta of man and laboratory animals. [Review]
- PPlacenta 2000; 21(4):289-305
- To better understand the role of the insulin-like growth factors (IGF-I and -II) and their binding proteins (IGFBPs 1-6) in placental development and function, it is important to review similarities …
To better understand the role of the insulin-like growth factors (IGF-I and -II) and their binding proteins (IGFBPs 1-6) in placental development and function, it is important to review similarities and differences between species in expression of the respective mRNAs. In human placenta, IGF-II mRNA is expressed in chorionic mesoderm and first trimester villous cytotrophoblast, but not in syncytiotrophoblast. In contrast, in rhesus monkey placenta, IGF-II mRNA is expressed in syncytiotrophoblast but not in chorionic mesoderm. IGFBP-3 mRNA is present in the chorionic mesoderm of placental villi from both these species and may modulate IGF-II action through a paracrine mechanism. In rodent placentae, IGF-II mRNA is expressed both in fetal mesoderm and in the trophoblast of the placental labyrinth. In guinea pig, where IGFBP-5 mRNA is expressed in the marginal and interlobular syncytium and IGF-II mRNA in the labyrinth, interaction between IGF-II and IGFBP-5 mRNA may be involved in vascularization of the placenta by fetal vessels. In sheep placenta, IGF-II mRNA is expressed, not in the trophoblast layer, but in the fetal mesoderm immediately adjacent to it. In the basal plate of human, rhesus monkey and baboon placentae, extravillous trophoblasts express IGF-II mRNA and uterine decidual cells IGFBP 1-6 mRNAs. The inference is that there is interaction between IGF-II and IGFBPs at the maternal-fetal interface of the primate placenta during trophoblast invasion and decidualization. IGFBP-1 expressed by the decidua may also interact with alpha(5)beta(1)integrin expressed by the extravillous trophoblast. The placentae of rodents are also of the invasive type. Glycogen cells of the mouse placenta are analogous with human extravillous trophoblast and express IGF-II mRNA. However, expression of IGFBP mRNAs in the mouse, as in the guinea pig, is confined to non-decidualized endometrium and myometrium. IGF-II mRNA is strongly expressed by trophoblasts invading uterine vessels in human and guinea pig placentae. Interactions probably occur between IGF-II expressed by these trophoblasts and IGFBPs expressed in the vessel walls. However, it is possible that IGFBPs expressed by maternal vessels are associated with processes that are independent of trophoblast invasion. Thus, IGFBP-3 mRNA is highly expressed in the maternal blood vessels of the non-deciduate sheep placenta. Findings to date highlight the diversity in the expression of the IGF system among placentae of man and different laboratory animals, and even between closely related species. Comparative studies will continue to be required to understand the functional role of IGFs and IGFBPs in each species.
- Intrauterine signaling and embryonic implantation. [Review]
- BSBiol Signals 1996 Mar-Apr; 5(2):111-21
- In mammals, the uterus is modified to be able to contain a pregnancy and nurture the developing embryo. In deciduate mammals, this is apparently due to formation of a special compartment, lined with …
In mammals, the uterus is modified to be able to contain a pregnancy and nurture the developing embryo. In deciduate mammals, this is apparently due to formation of a special compartment, lined with decidual tissue, in which a semi-allogeneic (or even allogeneic, after embryo transplantation) pregnancy is accommodated. This review treats the mechanisms which have been evoked to explain the implantation of the egg and the decidualization of the implanting endometrium. At least three different neurochemicals have been considered to mediate induction of this response: histamine, prostaglandins and platelet-aggregating factor. Their importance is reviewed. The ability of the endometrium to transform into decidual tissue is contingent on the presence of the epithelium. The role of the epithelium is temporary, however, since it dies and is sloughed within a day of the induction. Studies of progesterone-dependent changes in the epithelial reaction to preimplantation pregnancy are considered.
- Histology of the late-stage placentae in the matrotrophic skink Chalcides chalcides (Lacertilia; Scincidae). [Journal Article]
- JMJ Morphol 1993; 216(2):179-195
- Examination of late-stage placental material of the lizard Chalcides chalcides from the Hubrecht Laboratorium (Utrecht, The Netherlands) reveals several cytological and histological specializations t…
Examination of late-stage placental material of the lizard Chalcides chalcides from the Hubrecht Laboratorium (Utrecht, The Netherlands) reveals several cytological and histological specializations that appear to have been superimposed over a morphological pattern that is typical for squamates. The chorioallantoic placenta is highly vascularized and consists of a single mesometrial placentome and a generalized paraplacentomal region, both of which are epitheliochorial. The placentome is deciduate, and contains deeply interdigitating folds of hypertrophied uterine and chorioallantoic tissue. Chorionic epithelium lining the placentome comprises enlarged, microvilliated cells, a small proportion of which are diplokaryocytes. The placentomal uterine epithelium is not syncytial and consists of enlarged cells bearing microvilli. The yolk sac placenta is a true omphaloplacenta (sensu stricto), being formed by juxtaposition of uterine tissues to an avascular, bilaminar omphalopleure. Epithelium of the omphalopleure is stratified and is hypertrophied into papillae that project into detritus of the uterine lumen. The omphalopleure is separated from the yolk sac proper by a yolk cleft that is not confluent with the exocoelom and is not invaded by the allantois. Neither an omphalallantoic placenta nor a true choriovitelline placenta is present in late gestation. Morphologically, the mature placentae of C. chalcides are among the most specialized to have been described in reptiles, reflecting the substantial maternal-fetal nutrient transfer that occurs in this species. © 1993 Wiley-Liss, Inc.
- Ultrastructure of the full-term shark yolk sac placenta. I. Morphology and cellular transport at the fetal attachment site. [Journal Article]
- JUJ Ultrastruct Res 1985; 91(3):192-206
- During ontogeny, the yolk sac of some viviparous sharks differentiates into a yolk sac placenta that persists to term. The placenta is non-invasive and non-deciduate. Hematrophic transport is the maj…
During ontogeny, the yolk sac of some viviparous sharks differentiates into a yolk sac placenta that persists to term. The placenta is non-invasive and non-deciduate. Hematrophic transport is the major route of nutrient transfer from mother to fetus. The placental unit consists of: (1) an umbilical stalk; (2) the smooth, proximal portion of the placenta; (3) the distal, rugose portion; (4) the egg envelope; and (5) the maternal uterine tissues. Exchange of metabolites is effected through the intervening egg envelope. The distal rugose portion of the placenta is the fetal attachment site. It consists of: (1) surface epithelial cells; (2) a collagenous stroma with vitelline capillaries; and (3) an innermost boundary cell layer. The columnar surface epithelial cells are closely apposed to the inner surface of the egg envelope. Wide spaces occur between the lateral margins of adjacent cells. Surface epithelial cells contain an extensive apical canalicular-tubular system and many whorl-like inclusions in their basal cytoplasm. Capillaries of the vitelline circulation are closely situated to these cells. A well-developed collagenous stroma separates the surface epithelium from an innermost boundary cell layer. In vitro exposure of full-term placentae to solutions of trypan blue and horseradish peroxidase (HRP) reveals little uptake by the smooth portion of the placenta but rapid absorption by the surface epithelial cells of the distal, rugose portion. HRP enters these cells by an extensive apical system of smooth-walled membranous anastomosing canaliculi and tubules. Prominent whorl-like inclusions that occupy the basal cytoplasm of the surface cells, adjacent to the pinocytotically active endothelium of the vitelline capillaries, are hypothesized to be yolk proteins that are transferred from the mother to embryo throughout gestation.
- Ultrastructural observations on the placenta of the alpaca (Lama pacos). [Journal Article]
- PPlacenta 1980 Jan-Mar; 1(1):21-32
- The alpaca is one of the four South American species of the family Camelidae. Its placenta, like that of other camelids, is diffuse and epitheliochorial in type. The chorionic epithelium is thrown in…
The alpaca is one of the four South American species of the family Camelidae. Its placenta, like that of other camelids, is diffuse and epitheliochorial in type. The chorionic epithelium is thrown into unbranched villi or folds which are closely apposed to corresponding undulations of the uterine epithelium, and the fetal-maternal interface consists of an intricate interdigitation of fetal and maternal microvilli. In late gestation both chorionic and uterine epithelia are deeply indented by placental capillaries, so that the minimum intercapillary distance across the diffusion pathway may be as little as 2 microns. This distance appears to be less than that found in the epitheliochorial placenta of any other species of domestic ungulate in late gestation: it may be one of several adaptations to pregnancy at high altitude. Delivery of the fetal membranes occurs some 45 minutes after the birth of the fetus. The placenta is non-deciduate.
- [Evolution of the allantoid placenta in placental mammals]. [Journal Article]
- AAArkh Anat Gistol Embriol 1979; 77(7):5-16
- The article surveys the literature concerning comparative morphology of allantoic placenta and presents some evolutionary-morphological conclusions. The initial form of allantoic placenta is non-deci…
The article surveys the literature concerning comparative morphology of allantoic placenta and presents some evolutionary-morphological conclusions. The initial form of allantoic placenta is non-deciduate that occurs in 7 orders of placental mammals. The non-deciduate placenta is especially characteristic for lower primates and Cetacea. The non-deciduate placenta in lower primates and the fact that in some modern species of insectivores the non-deciduate placenta is also preserved speaks in favour of the opinion that insectivores of the Cretaceous period had non-deciduate placenta. The non-deciduate placenta in Cetacea that take their origin from ancient carnivores (from procreodonts) demonstrates, in its turn, that the non-deciduate placenta was the initial form. The deciduate placenta was the means for changing many of vital activities of the organism--it is connected with shortening or lengthening of individual life duration and duration of pregnancy. In the course of evolution the allantoic placenta improved towards intensified metabolism between the embryo (fetus) and the maternal organism. Relations between the evolution of mature specimens and evolutional changes in placenta are at their initial stage of investigation.