Library

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Electronic Resource
    Electronic Resource
    Functional Morphology of Equine Pre-ovulatory Cumulus-oocyte Complexes (2005)
    Berlin, Germany : Blackwell Verlag GmbH
    Anatomia, histologia, embryologia 34 (2005), S. 0 
    Details
    ISSN: 1439-0264
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Knowledge of the functional morphology of equine cumulus-oocyte-complexes (COCs) shortly before ovulation is scarce. Therefore the aim of our studies was to characterize COCs matured in vivo by light microscopy, transmission electron microscopy (TEM), scanning electron microscopy (SEM) and immunohistochemistry (ICC). Pre-ovulatory COCs were obtained by ultrasound-guided transvaginal aspiration of pre-ovulatory follicles of 26 pony mares. The morphology of pre-ovulatory COCs was compared to that of immature COCs obtained by slicing of ovaries from the slaughterhouse. As shown by light microscopy and SEM, immature COCs possess numerous round, densely packed cumulus cells, which contact each other and possess merely single short processes. Contrary, in pre-ovulatory oocytes the cumulus cells are widely separated but send long cytoplasmic processes to the zona pellucida (ZP). All the cumulus cells are embedded in a huge amount of homogenous extracellular matrix. As shown by alcian blue staining and Periodic Acid Schiff Reaction (PAS) with and without amylase digestion, this matrix contains glycoproteins and acidic and sulphated glycosaminoglycans. In pre-ovulatory COCs both the oocyte and the cumulus cells produce glycosaminoglycans, whereas immature COCs are negative for alcian blue. Similarly, glycoproteins are synthesized in pre-ovulatory, but not in immature COCs. As shown by ICC, hyaluronic acid is one of the most abundant mucopolysaccharide in the pre-ovulatory COC. The high synthetic activity of the cumulus cells in the pre-ovulatory COC is confirmed by TEM showing densely packed endoplasmic reticulum (ER) and accumulation of glycogen in the cumulus cells. Our results imply that in the equine in vitro maturation of the oocyte is characterized by the cumulus cells synthesizing an extracellular matrix of glycoproteins and acidic and sulphated glycosaminoglycans. The extensive production of extracellular, water-binding matrix in the pre-ovulatory COC ensures mechanical protection and nutrition of the oocyte.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1439-0264.2005.00669_58.x
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Regulation of Cumulus Cell Numbers in the Course of the Canine Estrous Cycle (2005)
    Berlin, Germany : Blackwell Verlag GmbH
    Anatomia, histologia, embryologia 34 (2005), S. 0 
    Details
    ISSN: 1439-0264
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: In the canine, success rates of assisted reproduction techniques are very low. Since cumulus cells are known to play an essential role during the in vitro maturation (IVM) of oocytes, the aim of this study was to investigate the regulation of cumulus cell numbers in the course of the canine estrous cycle. Eighty-two cumulus-oocyte-complexes (COCs) were obtained from 16 bitches undergoing elective ovariectomy during proestrus, estrus, metestrus and anestrus. First, mean cumulus cell numbers during the different stages of the cycle were compared. Then the incidence of programmed cell death (apoptosis) was detected by terminal deoxynucleotidyl transferase mediated dUTP labelling (TUNEL). Scanning electron microscopy (SEM) was used to confirm the presence of apoptotic cumulus cells. Additionally, mitosis was detected by using antibodies directed against the nuclear cell proliferation-associated antigen Ki-67. The mean number of cumulus cells in the COCs increased from proestrus to estrus (168.2 ± 9.2 to 265.5 ± 32.7, P 〈 0.01) and decreased from estrus to metestrus (265.5 ± 32.7 to 139.1 ± 10.7, P 〈 0.01) till anestrus (150.0 ± 8.3, P 〈 0.01). The percentage of apoptotic cumulus cells was generally very low during proestrus and oestrus (3.3% and 12.6%, P 〈 0.01) and distinctly increased during metestrus (83.1 %, P 〈 0.001). The predominance of apoptosis in the cumulus cells during metestrus was confirmed by SEM, which showed a high number of cells revealing cell shrinkage, loss of membrane integrity and cell disruption. Mitosis was highest during proestrus (2.7%) and oestrus (2.6 %) and decreased in the course of metestrus (1.8%) and anestrus (0.2%, P 〈 0.05).Our results imply that the distinct increase of cumulus cell numbers during proestrus and oestrus is due to increased mitosis and reduced apoptosis. The distinct reduction of cumulus cells during metestrus is predominantly regulated by apoptosis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1439-0264.2005.00669_59.x
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Embryo-maternal Communication during the First Days of Embryonic Life (2005)
    Berlin, Germany : Blackwell Verlag GmbH
    Anatomia, histologia, embryologia 34 (2005), S. 0 
    Details
    ISSN: 1439-0264
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: The mechanisms of embryo-maternal communication during the first days of embryonic life are largely unknown. Using the bovine as a model, the aims of our study were to morphologically characterize the interaction between the pre-implantation embryo and the epithelium of the maternal ampulla, isthmus and uterotubal junction by light and scanning electron microscopy. For this purpose, oviducts were removed from cows revealing a functional corpus luteum on day 3 after insemination. These were compared to oviducts removed on day 3 (metestrus) of the estrous cycle. Three days after insemination, the majority of the epithelial cells in the ampulla were secretory cells distinctly protruding into the oviductal lumen. Contrary the ampulla of cows on day 3 of the cycle predominantly revealed ciliated cells in the oviductal epithelium. As shown by Periodic Acid Schiff reaction (PAS) with and without amylase digestion, the secretory cells of the ampulla synthesized merely glycoproteins during metestrus, but large amounts of glycogen during pregnancy. In the isthmus no morphological differences were seen between pregnant and cyclic cows. The most conspicuous finding during pregnancy was seen in the uterotubal junction: Vital cumulus cells embedded in between epithelial cells had developed short cytoplasmic processes intensely contacting the epithelial uterine cells. The embryos obtained ex vivo were regularly covered with a thick layer of homogenous extracellular matrix. Contrary embryos produced in vitro– both with and without coculture with oviductal cells –revealed a clearly visible zona pellucida with spongy appearance and numerous pores. Our results imply that already during the first days of life there is intense interaction of the pre-implantation embryo and the maternal genital tract part of which may be mediated by cumulus cells.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1439-0264.2005.00669_60.x
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Book review (2004)
    Berlin, Germany : Blackwell Verlag GmbH
    Anatomia, histologia, embryologia 33 (2004), S. 0 
    Details
    ISSN: 1439-0264
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1439-0264.2004.00549.x
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Functional Morphology of the Zona Pellucida (2001)
    Oxford UK : Blackwell Science Ltd.
    Anatomia, histologia, embryologia 30 (2001), S. 0 
    Details
    ISSN: 1439-0264
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: The zona pellucida (ZP) is an extracellular matrix surrounding the oocyte and the early embryo that exerts several important functions during fertilization and early embryonic development. The ZP of most mammalian species is composed of three major glycoproteins that show considerable heterogeneity due to extensive post-translational modifications. Sodium dodecyl sulphate polyacrylamide gel electrophoresis of the ZP reveals three to four glycoproteins which have been nominated ZP1, ZP2, ZP3 and ZP4. As cloning and characterization of the ZP genes of a variety of mammalian species including domestic animals show a high homology, three classes of ZP genes, ZPA, ZPB and ZPC can be discerned. The corresponding proteins were named ZPA, ZPB and ZPC. Whereas in the mouse ZPB is the primary sperm receptor, the situation is more complicated in other species. For instance, in the pig ZPA has been shown to possess receptor activity. Interaction between gametes during fertilization is at least in part regulated by carbohydrate moieties of the ZP and carbohydrate-binding proteins of the sperm surface. In domestic animals zona proteins are expressed in both the oocyte and granulosa cells in a stage-specific pattern and may play a role in granulosa cell differentiation. The role of ZP glycoproteins in immunocontraception is briefly discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1046/j.1439-0264.2001.00337.x
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    Morphology of Canine Cumulus–Oocyte Complexes in Pre-pubertal Bitches (2003)
    Berlin, Germany : Blackwell Verlag GmbH
    Anatomia, histologia, embryologia 32 (2003), S. 0 
    Details
    ISSN: 1439-0264
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: The morphology of canine cumulus–oocyte complexes (COCs) before puberty is still unknown. Therefore, the aim of our study was to elucidate the morphological characteristics of pre-pubertal oocytes and cumulus cells by light microscopy, scanning electron microscopy and transmission electron microscopy. The pre-pubertal oocyte was characterized by accumulation of lipid yolk droplets in the cytoplasm as well as high energy metabolism, low protein synthesis and high transcriptional activity of the cumulus cells. The cumulus cells, which revealed a prominent nucleus and few cytoplasm, communicated with each other by few short processes and exhibited merely a small amount of processes reaching the oocyte. Our studies imply that both the oocyte and the cumulus cells of canine COCs before puberty reveal characteristic morphological features which are correlated with changes in oocyte metabolism and cumulus cell communication.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1046/j.0340-2096.2003.00514.x
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    Handbuch Pferdepraxis (2000)
    Oxford, UK : Blackwell Science, Ltd
    Anatomia, histologia, embryologia 29 (2000), S. 0 
    Details
    ISSN: 1439-0264
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1046/j.1439-0264.2000.00237.x
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 8
    Electronic Resource
    Electronic Resource
    Buchbesprechungen/Book Reviews (2003)
    Berlin, Germany : Blackwell Verlag GmbH
    Anatomia, histologia, embryologia 32 (2003), S. 0 
    Details
    ISSN: 1439-0264
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1046/j.1439-0264.2003.00474.x
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 9
    Electronic Resource
    Electronic Resource
    Topography of growth hormone receptor expression in the bovine embryo (1998)
    Springer
    Histochemistry and cell biology 109 (1998), S. 417-419 
    Details
    ISSN: 1432-119X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract  Using in situ hybridization, mRNA encoding the growth hormone receptor (GHR) was localized in preimplantation embryos produced by in vitro fertilization (IVF) as well as in 30- to 70-day-old bovine embryos. In IVF embryos the transcript of GHR was demonstrated in the inner cell mass of 8-day-old blastocysts. In 30-day-old embryos, the mesonephros was the first organ to express the mRNA of GHR. In 40-day-old embryos, the transcript was found in the neurones of the spinal ganglions, the splanchnic nerves and the motoneurones of the spinal cord, in the vascular endothelium, and in the developing striated muscle tissue. Colocalization of the protein by immunohistochemistry showed an identical distribution pattern of GHR in 30- to 70-day-old embryos.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004180050243
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 10
    Electronic Resource
    Electronic Resource
    Effects of hormones on the prostate in adult and aging men and animals (1995)
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 30 (1995), S. 282-292 
    Details
    ISSN: 1059-910X
    Keywords: Steroid hormones ; Peptide hormones ; BPH ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: Literature on the effect of steroid hormones (androgens, estrogens, and other steroids), of peptide hormones (e.g., prolactin), and growth factors (e.g., EGF, FGF, TGF-β), on the effect of castration and of experimental hormone application on the prostate is reviewed. Androgens have inductive, repressive, and interactive effects. They counterbalance an agonistic effect on proliferation and an antagonistic effect on cell death; they may influence DNA synthesis and induce the synthesis of substances with mitogenic effects on the prostate. Estrogens exert direct and indirect effects on the prostate. They suppress the secretion of gonatropins, thus repressing testicular androgen secretion. They stimulate the fibromuscular stroma and induce squamous metaplasia of the epithelium. Estrogens may also be involved in the onset of benign prostatic hyperplasia. Prolactin is preferentially bound in the diseased human prostate. An abundance of information has been gained on EGF, FGF, TGF-β, and other growth factors. They may be involved in the development of prostatic hyperplasia. Castration leads to a striking reduction in prostatic size in a short period of time due to autophagic and heterophagic processes. In castrated individuals, the prostate is enriched in androgen-independent cells. Experimental hormone application involves the substitution of androgens as well as anti-androgens, long-term application of different hormones, and application of combinations of drugs. The results of several studies are described. Further directions in the field of prostate research should concentrate on the role of growth factors in prostate development and pathology and on the effect of certain lectins on prostate diseases. We think that the investigation of interactions between steroid hormones and growth factors in normal and pathological neovascularization of the prostate is important. © 1995 Wiley-Liss, Inc.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jemt.1070300404
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...