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  • 1
    Electronic Resource
    Electronic Resource
    Ultrastructure of Human Unfertilized Oocytes and Polyspermic Embryos in an IVF-ET Program (1988)
    Oxford, UK : Blackwell Publishing Ltd
    Annals of the New York Academy of Sciences 541 (1988), S. 0 
    Details
    ISSN: 1749-6632
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Natural Sciences in General
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1749-6632.1988.tb22274.x
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  • 2
    Electronic Resource
    Electronic Resource
    Human Embryo Development and Pregnancies in an Homologous Granulosa Cell Coculture System (2000)
    Springer
    Journal of assisted reproduction and genetics 17 (2000), S. 1-12 
    Details
    ISSN: 1573-7330
    Keywords: blastocyst ; coculture ; human granulosa cells ; human embryos ; IVF implantation failures
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Purpose: Our purpose was to determine the effects of thecoculture of embryos on human granulosa cells (GCs) inpatients in the first cycle of IVF-ET treatment and in patientswith repeated implantation failures and to investigate thepresence of specific proteins in a 48-hr GC conditionedmedium and the GC ultrastructural characteristics. Methods: Eighteen patients with tubal or idiopathicinfertility were enrolled in this study: 7 patients (Trial 1) were inthe first cycle of IVF-ET treatment and 11 patients (Trial 2)had repeated implantation failures (one to five). Embryosfrom each patient were cocultured randomly either onhomologous granulosa cells or on a conventional culturemedium. Results: At the end of the coculture period (day 5 or 6),50% of the embryos (Trial 1) reached the blastocyst stage,with respect to 35% in Trial 2. The pregnancy rate perretrieval was 14.2 and 9%, respectively, in Trial 1 and inTrial 2. Many conditioned media showed proteins of 24–29kDa. and some of them showed additional proteins of 90kDa. The ultrastructural analysis of GCs showed healthy,metabolically active, protein-synthesizing, and mostlysteroidogenic cells. Conclusions: GC cultures improve embryo development butnot pregnancy rates both in Trial 1 and in Trial 2.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1009424528177
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  • 3
    Electronic Resource
    Electronic Resource
    Is the sperm-binding capability of the zona pellucida linked to its surface structure? A scanning electron microscopic study of human in vitro fertilization (1988)
    Springer
    Journal of assisted reproduction and genetics 5 (1988), S. 134-143 
    Details
    ISSN: 1573-7330
    Keywords: oocyte ; zona pellucida ; in vitro fertilization ; scanning electron microscopy ; gamete interaction
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The structure of the zona pellucida and the early interactions between human oocytes and spermatozoa were investigated in an in vitro fertilization program. Thirty-five mature (preovulatory) oocytes, 10 immature oocytes lacking a germinal vesicle, and 11 atretic oocytes which had not undergone fertilization at 10–20 hr after insemination were studied by light and scanning electron microscopy. Observed through employment of these techniques, the zona pellucida showed two basically different patterns: a mesh-like, spongy structure having wide and/or close meshes; and a compact, smooth surface. The smooth-surfaced zona was most commonly seen in the cultured oocytes belonging to the immature and atretic groups. These observations seem to show that the spongy appearance of the zona pellucida is related mainly to oocyte development and maturity. In this study, greater numbers of penetrating spermatozoa were noted on oocytes showing the mesh-like zona, in contrast to the presence of a few sperm flattened against its surface or the frank absence of sperm associated with oocytes having the more compact, smooth zona. It is likely that the condensation of the outer aspect of the zona pellucida causes a disorientation of sperm-binding sites, which would probably result in markedly reduced binding and penetration capacity with spermatozoa. These changes might ultimately lead to impairment of in vitro oocyte fertilizability.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01131175
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  • 4
    Electronic Resource
    Electronic Resource
    The angioarchitecture of estrous, pseudopregnant and pregnant rabbit ovary as seen by scanning electron microscopy of vascular corrosion casts (1997)
    Springer
    Cell & tissue research 288 (1997), S. 353-363 
    Details
    ISSN: 1432-0878
    Keywords: Key words: Ovary ; Vascularization ; Vascular corrosion casts ; Scanning electron microscopy ; Countercurrent mechanism ; Rabbit (New Zealand white)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract. Ovarian angioarchitecture was studied by scanning electron microscopy of vascular corrosion casts in estrous, pseudopregnant (stimulated with human chorionic gonadotropin) and pregnant rabbits. In all samples, the proper ovarian branch of the ovarian artery (ramus ovaricus) entered the ovarian hilus near the caudal pole of the organ and ran parallel to the major axis of the hilus. The extraovarian venous drainage was formed by several vessels emptying into a distal large vein. The ramus ovaricus exhibited various degrees of coiling and branched in the medulla. The coiling of the ramus ovaricus and its ramifications were maintained in all samples. A venous meshwork and/or flat vein branches closely enveloped the arterial coils found in the hilus and outer medulla. At this level numerous arteriovenous contacts were demonstrated in all samples. The coiled arteries, prior to entering the ovarian cortex, supplied several small peripheral follicles which were drained by the hilar veins. In the cortex the coiled arteries branched in numerous thin, straight or slightly undulated arterioles which supplied developing estrous follicles and pseudopregnant corpora lutea. The arterioles supplying the pregnant corpora lutea were long, large and tightly spiraled. The venous drainage followed the modifications of the arterial supply. These data demonstrate that ovarian cycle and pregnancy induced significant changes in the cortical vessels, which adapted their structure to the temporary functional needs of the recruited follicles or corpora lutea. Hilar and medullary vessels have permanent structures that may represent morphological devices for (a) a continuous control of the blood flow (spiral arteries) and (b) a local recirculation of endocrine products (arteriovenous contacts) comparable to the ”countercurrent mechanism” previously shown to operate in ovaries of other species, but not yet found in rabbits.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004410050821
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  • 5
    Electronic Resource
    Electronic Resource
    The three-dimensional structure of the zona pellucida in growing and atretic ovarian follicles of the mouse (1989)
    Springer
    Cell & tissue research 257 (1989), S. 247-253 
    Details
    ISSN: 1432-0878
    Keywords: Zona pellucida ; Ovarian follicles ; Atresia ; Ultrastructure ; Mouse
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The present study provides further details on the fine-structural three-dimensional architecture of the zona pellucida (ZP) in growing and atretic follicles of mice by use of ruthenium red in combination with the detergents Triton X100 and saponin. These detergents were used for extraction of the “soluble” fraction of the zonal proteins in an attempt to expose the “structural” zonal glycoproteins, which in turn can be viewed as minute three-dimensional networks upon transmission- and scanning electron-microscopic examination. By use of these methods, the ZP of growing follicles appeared to be formed by interconnected filaments which also bind to globular structures building up a three-dimensional lattice. In contrast, the ZP of stage I as well as other (II and III) stages of atretic follicles showed a structure characterized by the presence of closely packed granules connected with short filaments to form a close-mesh reticulum. This structural change of the ZP, which in the present study is also associated with the disappearance of “gap junctions” within the granulosa and cumulus cell population, might represent one of the early events involved in the onset of atresia. These changes, most probably depending on an altered secretory activity of both oocytes and follicle cells, might lead to a degradation of the ZP network structure and to its subsequent increased density (condensation). All these morphodynamic events eventually contribute to a sequestration of the oocyte in the early stage of atresia.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00261827
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  • 6
    Electronic Resource
    Electronic Resource
    Human zona pellucida during in vitro fertilization: An ultrastructural study using saponin, ruthenium red, and osmium-thiocarbohydrazide (1992)
    New York, NY [u.a.] : Wiley-Blackwell
    Molecular Reproduction and Development 32 (1992), S. 51-61 
    Details
    ISSN: 1040-452X
    Keywords: Oocyte ; Polypronuclear ovum ; Fertilization ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: The human zona pellucida (ZP) and its changes during in vitro fertilization in oocytes at different maturational stages and polypronuclear ova at one- to four-cells stages were studied by transmission electron microscopy (TEM) and correlative scanning electron microscopy (SEM). To define the microstructure of the ZP, its amorphous masking material was removed using a detergent (saponin), and its structural glycoproteins were stabilized with a cationic dye, ruthenium red, followed by osmium-thiocarbohydrazide treatment. These methods allowed in all samples the clear visualization of variously arranged networks of filaments composing the outer and inner surfaces of the ZP. These filaments were straight or curved, 0.1-0.4 μ in length and 10-14 nm thick as seen via TEM or 22-28 nm thick as seen via SEM (the difference in thickness was due to the presence of the metal coating for SEM). The filament arrangement was remarkably different between the inner and outer surfaces of the ZP and among the various stages studied. The filaments of the outer surface of the ZP were basically arranged in “large” and “tight” meshed networks. Mature oocytes and fertilized (polypronuclear) ova had a regular alternating pattern of wide and tight meshed networks of filaments. On the other hand, immature and atretic oocytes displayed almost exclusively a tight meshed network of filaments. The inner surface filaments of the ZP of unfertilized oocytes at any stage were arranged in repetitive structures characterized by numerous short and straight filaments anastomosing with each other and sometimes forming at the intersections small, rounded structures. After fertilization, the inner surface of the ZP displayed numerous areas where filaments fused together. Collectively, these data clearly reveal that oocyte maturation and fertilization in humans are accompanied by changes of ZP filaments arrangement, which may be relevant in the processes of binding, penetration, and selection of spermatozoa. © 1992 Wiley-Liss, Inc.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mrd.1080320109
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