ISSN:0002-9106    

DOI:10.1002/aja.1001520102

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1978

数据来源: WILEY

摘要:

AbstractDecidual tissue occurring within the human ovarian cortex was examined by light and electron microscopy. Of 21 ovarian specimens obtained at term (36–42 weeks of gestation), decidual cells were confirmed in each. Decidual cells were found within the tunica albuginea as single cells, in nodules, in polyps or in confluent sheets. Decidual cells exhibited several characteristics of cells engaged in secretory activity: abundant rough and smooth endoplasmic reticulum, numerous profiles of the Golgi complex and a large, euchromatic nucleus devoid of heterochromatin and displaying a prominent fibrous lamina. Peduncular protrusions at the periphery of the cell contained numerous dense bodies 0.4–0.9 μm in diameter. These dense bodies were bounded by a single membrane and contained granular subunits 30–60 nm in diameter. These granular subunits were observed in the process of apparent exocytosis, as well as free in the extracellular space. Secretory bodies and their granular content also were observed both in the region of the Golgi complex and partially extruded into peduncular processes. By far the greatest number of secretory bodies occurred within peduncular processes where they may be stored prior to release. Migration of a secretory body into a peduncular process and exocytosis from such a process appears to be an unusual mode of meocrine secretion, perhaps unique to decidual

ISSN:0002-9106    

DOI:10.1002/aja.1001520103

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1978

数据来源: WILEY

摘要:

AbstractFine‐structural features of ovarian decidual cells and their mode of secretion were examined by means of freeze‐fracture microscopy. Unique cortical peduncular processes contained secretory vesicles within the expanded peduncle tip, the membrane‐leaflets of which exhibited a particle‐poor E face adjacent to the vesicle lumen and a P face containing a greater particle number. Exocytosis from attached peduncles involved release of vesicular profiles 40–55 nm in diameter; small particles 8.5–11.5 nm in diameter were also observed at degranulation sites. In fractures revealing the E face of the plasmalemma, cytoplasmic portals at the bases of peduncular stalks were distinguishable from endocytic vesicles.The frequent occurrence of reflexive gap junctions associated with peduncles was shown by freeze‐fracture. However, there appeared to be no consistent spatial relationship between gap junctions, secretory peduncles, or sites of exocytosis. Freeze‐fracture analysis of the topography of reflexive gap junctional profiles revealed that such gap junctions share basic similarities with intercellular gap junctions. These similarities include particle size (8–10 nm); number of particles within clusters (20–40); and the presence of 5–15 nm particle‐free aisles. The finding in the present study of reflexive gap junctions occurring between peduncles and the cell soma, as well as between peduncles, suggests that the original definition of reflexive gap junctions as those existing between processes of the same cell should be broadened to include any gap junctional specialization formed between portions of the plas

ISSN:0002-9106    

DOI:10.1002/aja.1001520104

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1978

数据来源: WILEY

摘要:

AbstractThe annular hematoma of the shrew,Blarina brevicauda, is a specialized portion of the yolk‐sac wall. In this study, we have examined the fine structure of the different cellular components of the annular hematoma. Small pieces of the gestation sacs from seven pregnant shrews were fixed in glutaraldehyde and osmium tetroxide and processed for transmission electron microscopy. In the area of the trophoblastic curtain, the maternal capillary endothelial cells were hypertrophied and syncytial trophoblast surrounded the capillaries. Cellular trophoblast covered part of the luminal surface of the curtain region, whereas masses of apparently degenerating syncytium were present on other areas of the surface. Maternal erythrocytes, released into the uterine lumen from the curtain region, were phagocytized and degraded by the columnar cells of the trophoblastic annulus. No evidence of iron or pigment accumulation was evident in the parietal endodermal cells underlying the annular trophoblast. Parietal endodermal cells were characterized by cuboidal shape, widely dilated intercellular spaces, and cytoplasm containing granular endoplasmic reticulum. Endodermal cells of the visceral yolk‐sac accumulated large numbers of electron‐dense granules as well as glycogen in their cytoplasm. Hemopoietic areas and vitelline capillaries were found subjacent to the visceral endoderm. The various portions of the yolk‐sac wall ofBlarinaappear to perform complementary functions which are probably important in maternal‐fetal iron

ISSN:0002-9106    

DOI:10.1002/aja.1001520105

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1978

数据来源: WILEY

摘要:

AbstractReexamination of presomite human and rhesus monkey embryos in the Carnegie Collection provides no evidence to corroborate the hypothesis that the trophoblast is the source of all extraembryonic tissues in these embryos. Instead, the present study indicates that the developmental pattern of the yolk sac and extraembryonic mesoderm is homologous to that in other eutherian mammals. The primary yolk sac of 10‐ to 11 ‐day human blastocysts is partially filled with a meshwork of extraembryonic endoderm, whereas such a meshwork is absent in the rhesus monkey. It is suggested that this endodermal meshwork develops as the result of interstitial implantation in the human embryo. A small secondary yolk sac develops in 12‐ to 13‐day human and macaque embryos as the result of pinching off of a portion of the larger primary yolk sac. Development of a secondary yolk sac in higher primates appears to be related causally to differential rates of expansion of the blastocyst and primary yolk sac within the simplex uterus.The caudal margin of the primitive streak develops precociously in 12‐ to 14‐day human and macaque embryos, and this appears to be the source of all the extraembryonic mesoderm of the chorion, chorionic villi, and body stalk. It is suggested that the peripheral spread of extraembryonic mesoderm plays an inductive role in the development of chorionic villi, similar to other types of epithelial‐mesenchymal inductive interactions. In contrast to previous hypotheses, the human and macaque trophoblasts appear to give rise only to additiona

ISSN:0002-9106    

DOI:10.1002/aja.1001520106

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1978

数据来源: WILEY

摘要:

AbstractThe 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.

ISSN:0002-9106    

DOI:10.1002/aja.1001520107

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1978

数据来源: WILEY

摘要:

AbstractThe development and disappearance of the human tail between stages 14 and 22 were studied using scanning and transmission electron microscopy, supravital staining and light microscopy. The tail is a prominent feature of the human embryo during stage 14 and is composed of paired somites, mesenchyme and extensions of the neural tube, notochord and gut. The tail grows with the embryo through early stage 17 when it extends more than a millimeter from the trunk. Overgrowth by the trunk at the base of the tail may account for the loss of part of its length during late stage 17 and stage 18. However, during stage 17 cells begin to die in all structures throughout the tail. Cell death continues in the succeeding stages reaching massive numbers by stages 18 and 19, and the tail becomes less and less prominent with developmental time. Most of the dead cells are phagocytosed. The debris‐laden macrophages appear to migrate from the tail to the body. By late stage 21 or early stage 22 there is no free tail. We conclude that cell death has a major role in the destruction of tail structures and the concurrent loss of the human tai

ISSN:0002-9106    

DOI:10.1002/aja.1001520108

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1978

数据来源: WILEY

摘要:

AbstractOrgan explants from the canine prostate with and without methylprednisolone pretreatment were cultivated for ten days in Trowell's T‐8 medium or medium supplemented with testosterone and/or vitamin A. Upon termination of the experiments, explants were fixed and examined histologically. All glands from the most central section of each explant were graded according to epithelial type, and from these grades the proportion of acini with maintained columnar cells was calculated for each explant. Stromal cellular maintenance was also estimated. While a small proportion of explants from the vitamin‐treated and methylprednisolone‐pretreated groups showed epithelial maintenance, a combination of these treatments significantly increased such maintenance. Stromal maintenance was enhanced with methylprednisolone pretreatment but not by vitamin A. These results are in accord with the hypothesis that methylprednisolone acts to stabilize the lysosomal membrane, thus protecting tissue against the effects of ischemic shock. In protected explants vitamin A is able to maintain a columnar glandular epithelium. In a subsequent experiment a series of linoleic acid dosages was tested in the presence or absence of vitamin A. In neither case was this fatty acid of value in improving epithelial or stromal mainte

ISSN:0002-9106    

DOI:10.1002/aja.1001520109

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1978

数据来源: WILEY

ISSN:0002-9106    

DOI:10.1002/aja.1001520101

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1978

数据来源: WILEY