Library

feed icon rss

Your email was sent successfully. Check your inbox.

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

Proceed reservation?

Export
Filter
  • 2005-2009  (2)
  • 1
    ISSN: 1439-0264
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Carcinoma-in-situ (CIS) of the testis is known to be the pre-invasive stage of most human germ cell tumours (seminoma and non-seminoma), but the mechanisms leading to an increased pubertal proliferation of CIS cells after a long latency and to progression of CIS to an invasive malignancy are still not known. Additionally, CIS and seminoma have also been reported in equine testis (Veeramachaneni and Sawyer, 1998). The gap junctional protein and tumour suppressor gene connexin(cx)43 represents the predominant cx in human, canine and rodent testis so far and it is expected to play a key role for the regulation of both proliferation and differentiation of germ cells (spermatogonia and spermatocytes), and its gene- and protein-expression pattern is typical for the pubertal terminal differentiation of somatic Sertoli cells. Using cDNA-microarray analysis, in-situ hybridization (ISH), RT-PCR from tissue homogenate and semi-quantitative RT-PCR from well defined microdissected tubules with normal spermatogenesis, CIS, intratubular seminoma (ISe) and from seminoma cells from invasive seminoma we found a downregulation of cx43 starting in intratubular CIS, leading to a complete loss in most invasive seminoma cells. This indicates that regulation of cx43 expression takes place at transcriptional level confirming and expanding earlier studies of protein expression (Brehm et al., 2002). This reduction of cx43-expression suggests that an early intratubular derangement in cx43-gene expression and disruption of inter-cellular communication between Sertoli cells and/or Sertoli cells and pre-invasive tumour cells via cx43-gap junctions may play a role in the proliferation of CIS cells and seminoma cells and in the progression phase of testicular seminoma development.References  Veeramachaneni, D. N., and H. R.Sawyer, 1998: Carcinoma in situ and seminoma in equine testis. APMIS 106, 183–185.Brehm R., A. Marks, R. Rey, S. Kliesch, M. Bergmann and K. Steger, 2002: Altered expression of connexins 26 and 43 in Sertoli cells in seminiferous tubules infiltrated with carcinoma-in-situ or seminoma. J. Pathol. 197, 647–653.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 2
    Electronic Resource
    Electronic Resource
    Berlin, Germany : Blackwell Verlag GmbH
    Anatomia, histologia, embryologia 34 (2005), S. 0 
    ISSN: 1439-0264
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Efficient and well-regulated intercellular communication is essential to organize the activities of the different cell populations involved during growth and concomitant structural maturation of the skeleton. For direct cell-cell communication gap junctions composed of connexins (Cx) are present. So far 21 Cx types have been identified in mammals, which differ in molecular permeability as well as tissue expression pattern. To characterize the Cx distribution in the developing canine skeleton, samples from humerus, scapula and lumbar vertebrae of Beagle dogs aged 1.5, 3, 4.5 months and 1.5 years were fixed in Bouin's solution, decalcified with 25% EDTA and embedded in paraffin wax. Using immunohistochemistry and in situ hybridization, the expression of Cx 26, 30, 31, 32, 43, and 45 was studied in bone tissue plus associated epiphyseal and growth plate cartilage. Of all bone cells, osteoblasts showed the largest Cx expression repertoire: they were positive for Cx 26, 30, 32 and 43. After transformation into bone lining cells Cx43 expression was lost while in osteocytes only Cx 26 and 32 was detected. A wide variety of Cx reactions was also found in osteoclasts: Cx 26, 30, 32, and 43. In contrast, chondrocytes showed a much more restricted Cx expression pattern. Positive reactions were only seen in hypertrophic chondrocytes of epiphyseal cartilage (Cx 26, 31, 32) and in the proliferative (Cx32) and hypertrophic zone (Cx 26 and 32) of growth plate cartilage. Additionally, Cx31 was strongly expressed in the cellular layer of the periosteum covering areas of intensive bone modelling in the puppies. Age- and microlocation-dependent variations in expression and/or staining intensity were also observed in the other Cx types. These results demonstrated that canine bone cells are capable of synthesizing a wide variety of Cx types during skeletal development, thus propagating different cellular signals via gap junctions in a differentially regulated and requirement orientated manner.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...