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  • 1975-1979  (7)
  • Cell & Developmental Biology  (7)
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  • 1
    Electronic Resource
    Electronic Resource
    Junctional complexes in the preimplantation rabbit embryoSupported by grant HD 09462 from the National Institute of Child Health and Human Development. We would especially like to thank Dr. Karl Pfenninger for extensive assistance in freeze-cleave techniques with the blastocysts. (1975)
    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 181 (1975), S. 17-33 
    Details
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The morphology and development of junctional complexes between blastomeres of the preimplantation rabbit embryo were investigated using several approaches. Electron microscopic examination of embryos stained en bloc with uranyl acetate, and the study of junction permeability using horseradish peroxidase and lanthanum nitrate provided information on structure, intermembrane spacing and permeability of the junctional complexes. In addition, the freeze fracture technique was used with day 5 and day 6 blastocysts, since the large size of these embryos facilitated use of this method. These experiments showed that although rudimentary junctions were present between blastomeres of the early cleavage stages, effective tight junctions were not present until the blastocyst stage. Electron microscopic examination of thin sections revealed apical foci of membrane approximation or “fusion” between trophoblast cells by day 4. Freeze fracturing revealed a lattice of interconnecting ridges (on the A face) and grooves (on the B face) in the apical region between trophoblast cells of the day 5 blastocyst. This lattice formed a continuous band along the apical margin of each cell, and therefore constituted a zonula occludens. The zonula occludens of the day 5 blastocyst averaged 2-3 ridges per lattice, while day 6 blastocysts had lattices that averaged 5-6 ridges. Also seen in the freeze fracture replicas from the day 5 and day 6 blastocysts were local accumulations of intramembranous particles on the A face. These particles were often observed in aggregates similar to those of previously described gap junctions. It could not be determined whether these small regions of particles were true gap junctions or a possible primitive form of gap junction because the complementary pitted surfaces (B face pits) were not demonstrated.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ar.1091810103
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  • 2
    Electronic Resource
    Electronic Resource
    The nonuniform distribution of acidic components on the human placental syncytial trophoblast surface membrane: A cytochemical and analytical studyThis work was supported by National Institute of Health Traineeship GM02016 (D.M.N.), National Institute of Child Health and Human Development grants #5 R01 HD06415 (A.C.E.) and #HED 5 R01 HDO 7562 (C.H.S.), and the National Foundation for March of Dimes grant #CRBS - 309 (C.H.S.). (1976)
    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 184 (1976), S. 159-181 
    Details
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The surface coat of syncytial trophoblast from term human placentas was studied using cytochemical methods (colloidal iron, alcian bluelanthanum nitrate, dialyzed iron) in coordination with tissue enzyme digestions (trypsin, neuraminidase) and sialic acid analyses. The presence of at least two highly acidic anionic components that contribute significantly to the surface negativity of trophoblast has been demonstrated. The first of these, sialic acid, was removed with neuraminidase. Tissue digestion with this glycosidase was accompanied by a decrease in trophoblast surface staining with colloidal iron, a decrease in tissue sialic acid, and an increase in the concentration of sialic acid in the incubating medium. Results from methylation experiments were consistent with the presence of sialic acid. The second anionic component(s) was identified by removal with trypsin of a glycocalyx constituent that stained with both colloidal iron and lanthanum. After trypsinization, tissue sialic acid levels were not significantly different from control values, and no detectable sialic acid was present in the incubating medium. The identity of this anionic component has not been established. Both sialic acid and nonsialic acid acidic components are distributed in higher density on membrane of microvilli than on intermicrovillous surface membrane. In addition, the sialic acid moieties appear to be clustered in the glycocalyx.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ar.1091840204
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  • 3
    Electronic Resource
    Electronic Resource
    Differentiation and migration of endoderm in the rat and mouse at implantationThis study was supported by grants HD 04962 and HD 10342 from the National Institue of Child Health and Human Development. (1978)
    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 190 (1978), S. 65-77 
    Details
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The initial differentiation of endoderm at the time of onset of implantation, and the subsequent rapid differentiation of visceral and parietal endoderm were studied in the rat and mouse. Transmission electron microscopy illustrates the reorientation and loosening of embryonic cell mass cells during implantation, as well as cytological evidence that endoderm cells have differentiated. Using scanning electron microscopy, parietal endoderm consists of individual stellate cells with numerous peripheral branching filopodia. As these cells migrate abembryonically, the rest of the embryonic cell mass becomes recom-pacted. The visceral endoderm proliferates and forms a columnar epithelium which has the cytological characteristic of an absorptive epithelium and is able to ingest exogenous proteins. Thus, by 24 hours after implantation, the two endo-dermal derivatives have assumed widely diverse shapes and different types of associations and rates of replication, and are probably performing different functions.
    Additional Material: 16 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ar.1091900107
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  • 4
    Electronic Resource
    Electronic Resource
    Mouse uterine glands during the delayed and induced implantation periodsThis study was supported by Grants HD 04962 and HD 10342 from the National Institute of Child Health and Human Development and by National Institute of Health Traineeship Grant GM 021025 to the Department of Anatomy and Neurobiology, Washington University School of Medicine, St. Louis, Missouri. (1978)
    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 190 (1978), S. 271-283 
    Details
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Mouse uterine glandular epithelium during the lactationally delayed implantation period and after estradiol induction of implantation was investigated using light and electron microscopy. During the delayed implantation period the lumen of this simple tubular gland is narrowed. The glandular epithelial cells have a well developed Golgi complex lateral to the nucleus, and numerous cisternae of smooth and rough endoplasmic reticula (RER) and many electron lucent apical vesicles of sizes up to 0.2 μm in diameter near the luminal border. The basal region contains lipid droplets and dispersed, irregular cisternae of RER. Twenty-four hours after the administration of 17β-estradiol the glandular lumina become dilated but the luminal content does not stain with azure B. Ultrastructurally the glandular cells are not remarkably different from those seen during the delay period. However, by 48 hours after estradiol administration the glandular lumina are not only dilated but filled with material which stains intensely with azure B and is ultrastructurally dense and homogeneous. The apical region of the glandular cells contains granules up to 0.4 μm in diameter composed of electron dense material similar in density to that seen in the glandular lumen. In addition, the Golgi complex has assumed a position apical to the nucleus, and the basal RER has an increased number and more orderly arrangement of cisternae.The changes seen in the uterine glands after the induction of implantation during the delay period are apparently indicative of increased secretory activity of the glandular epithelia. However, the contribution of the glands to the changes in uterine fluid composition has yet to be established.
    Additional Material: 14 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ar.1091900210
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  • 5
    Electronic Resource
    Electronic Resource
    The implantation chamber, blastocyst and blastocyst imprint of the rat: A scanning electron microscope studyThis study was supported in part by Grant HD-04962 from the National Institute of Child Health and Human Development. Initial acquisition of the scanning electron microscope used was made possible by Health Sciences Advancement Award 5 SO4 RR 06115. (1975)
    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 182 (1975), S. 137-149 
    Details
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Splitting the uterus longitudinally through implantation sites makes it possible to obtain access to blastocysts and implantation chambers during stages of implantation of the blastocyst in the rat. On the afternoon of day 5 of pregnancy, blastocysts lie in a shallow antimesometrial depression and tend to fall free of the uterus when the chamber is opened. On day 6, blastocysts are oriented in a mesometrial-antimesometrial plane, occupy a distinct implantation chamber, and tend to adhere to one side or the other of the uterus, leaving an imprint on the contralateral side. After about noon of day 6, some of the blastocysts split in half laterally, and by day 7 all blastocysts which are exposed are split. In addition to demonstrating increased adhesion of blastocyst to uterine epithelium, the procedure clearly shows the progressive elongation of the implantation chamber. The embryonic cell mass is specifically oriented on day 6, and is clasped but not distorted, whereas the abembryonic trophoblast is slightly compressed and indented by the uterine epithelium. The microvilli of the uterine epithelium within the imprint become progressively flattened when compared to the microvilli of the implantation chamber outside of the imprint. The method provides a means of gaining direct access to the surface of uterine epithelium precisely where it has been in association with the blastocyst not only for scanning electron microscopy but also for studies of the properties of the surface constituents.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ar.1091820202
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  • 6
    Electronic Resource
    Electronic Resource
    The annular hematoma of the shrew yolk-sac placentaThis investigation was supported by funds from Grant HD 11658 from the National Institute of Child Health and Human Development and NIH Research Career Development Award K04 HD00238 (B.K.), NICHHD Grant HD 10344 (A.E.) and National Science Foundation Grant G6435X (W.W.). (1978)
    New York, NY [u.a.] : Wiley-Blackwell
    American Journal of Anatomy 152 (1978), S. 45-57 
    Details
    ISSN: 0002-9106
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The 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 of Blarina appear to perform complementary functions which are probably important in maternal-fetal iron transfer.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/aja.1001520105
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  • 7
    Electronic Resource
    Electronic Resource
    Cytological development of yolk sac endoderm and protein-absorptive mesothelium in the little brown bat, Myotis lucifugusSupported by funds from the National Institute of Child Health and Human Development Grants HD-06415 (A. E.) and HD06734 (B. K.), and by a grant from the National Science Foundation, GB-6435X (W. W.). (1976)
    New York, NY [u.a.] : Wiley-Blackwell
    American Journal of Anatomy 146 (1976), S. 1-29 
    Details
    ISSN: 0002-9106
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The yolk sac of the little brown bat is unusual in that during the course of gestation both the inner endodermal cells (bordering the yolk sac cavity) and outer mesothelium (facing the exocelom) form simple columnar epithelia which persist throughout gestation. These endodermal cells develop an extensive system of agranular endoplasmic reticulum, numerous lipid droplets and unusual “giant” mitochondria. During development the Golgi apparatus changes position from the apical to the basal side of the nucleus, reversing the polarity of the cells. In general, the endodermal cells have cytological features suggestive of synthetic or secretory activity. The mesothelial cells develop an extensive “absorptive apparatus” in their apices, while large crystalloid-containing granules become numerous in their basal cytoplasm. The mesothelial cells have large deposits of glycogen, especially during mid-gestation, but few mitochondria and little granular endoplasmic reticulum. Endodermal cells do not absorb exogenous protein (peroxidase) even if it is injected directly into the yolk sac cavity. However, placement of peroxidase either in the exocelom or in the maternal vascular system results in the appearance of this protein in the “absorptive apparatus” of mesothelial cells as well as in macrophages in the stroma of the yolk sac. While evidence of absorption was clear, no direct evidence of transport of tracer to fetal blood vascular system was obtained. It is postulated that a major function of the hypertrophied mesothelial cells during gestation is the absorption of proteins and possibly other substances from the exocelomic fluid. The major function of the hypertrophied endodermal cells may be synthesis and secretion of substances into the fetal circulation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/aja.1001460102
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