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
  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Anatomy and embryology 190 (1994), S. 515-520 
    ISSN: 1432-0568
    Keywords: Human testis ; Intermediate filaments ; Sertoli cells ; Differentiation ; Spermatogenic impairment
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Testicular biopsies of infertile patients are often characterized by a mixed atrophy, in which different types of spermatogenic lesions are found in adjacent tubules. In order to evaluate a possible involvement of the state of differentiation of the Sertoli cells, the distribution pattern of cytokeratin and vimentin intermediate filaments within the seminiferous epithelium of 228 biopsy specimens with normal spermatogenesis (n=10), mixed atrophy (n= 206) or Sertoli Cell Only Syndrome (n=12) were investigated by means of immunohistochemical techniques. Sertoli cells were regularly found to show vimentin expression in tubules with normal spermatogenesis as well as in tubules with any kind of spermatogenic impairment including SCO. Cytokeratin expression as a marker showing lack of differentiation was common in Sertoli cells of tubules with arrest of spermatogenesis at the level of spermatogonia, and was occasionally associated with arrest at the level of primary spermatocytes or with SCO. Ultrastructural examination of tubules with spermatogonial arrest revealed Sertoli cells with features of typical fetal or prepubertal Sertoli cells, such as round to ovoid nuclei without indentations, stacks of rough ER and spot desmosomes. These data suggest that spermatogenic arrest at the level of spermatogonia might be due to functional impairment of the associated Sertoli cells, which have maintained or regained an undifferentiated state and are not able to initiate or trigger the process of spermatogonial differentiation.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Anatomy and embryology 168 (1983), S. 269-275 
    ISSN: 1432-0568
    Keywords: Blood Testis barrier formation ; Meiosis ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Postnatal formation of the Blood-Testis Barrier (BTB) in the rat was studied by either fixation in hypertonic fixative or employing lanthanum tracer. After 15 days of age, meiosis has reached different stages of spermatogenesis in differnt zones of the seminiferous cords. Only in those parts where germ cells are in the pachytene stage of meiosis do Sertoli cells form an effective barrier or tight compartment. Between 16 and 19 days of age, final formation of the BTB, which is to be found in the adult rat testis, occurs by zygotene and then leptotene stages successively entering the tight compartment. Thus, formation of a BTB by Sertoli cells does not occur synchronously along the length of the seminiferous cord but in accordance with the stage of meiosis of the associated germ cells.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 3
    facet.materialart.
    Unknown
    Detroit, etc. : Periodicals Archive Online (PAO)
    American Imago. 23:3 (1966:Fall) 257 
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 4
    facet.materialart.
    Unknown
    Detroit, etc. : Periodicals Archive Online (PAO)
    American Imago. 33:1 (1976:Spring) 98 
    ISSN: 0065-860X
    Topics: Medicine , Psychology
    Notes: DISCUSSION OF THE LAURIE SCHNEIDER'S PAPER
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 5
    facet.materialart.
    Unknown
    Detroit, etc. : Periodicals Archive Online (PAO)
    American Imago. 41:4 (1984:Winter) 389 
    ISSN: 0065-860X
    Topics: Medicine , Psychology
    Notes: OTTO RANK: A CENTENNIAL TRIBUTE
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 6
    facet.materialart.
    Unknown
    Detroit, etc. : Periodicals Archive Online (PAO)
    American Imago. 52:3 (1995:Fall) 243 
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Histochemistry and cell biology 112 (1999), S. 215-220 
    ISSN: 1432-119X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract  In order to further characterize the Sertoli cell state of differentiation, we investigated the expression of connexin 43 (cx43) protein in the testis of adult men both with normal spermatogenesis and associated with spermatogenic impairment, since cx43 is first expressed during puberty. Cx43 protein was found as a single 43-kDa band on western blots of extracts of normal human testicular material. Cx43 immunoreactivity was generally present between Leydig cells. Within the normal seminiferous epithelium cx43 immunoreactivity was localized between adjacent Sertoli cells, except at stages II and III of the seminiferous epithelial cycle when primary spermatocytes cross from the basal to the adluminal compartment suggesting a stage-dependent Sertoli cell function. While testes with hypospermatogenesis and spermatogenic arrest at the level of round spermatids or spermatocytes revealed a staining pattern similar to that of normal adult testis, the seminiferous tubules showing spermatogenic arrest at the level of spermatogonia and Sertoli-cell-only syndrome were completely immunonegative. We therefore assume that severe spermatogenic impairment is associated with a population of Sertoli cells exhibiting a stage of differentiation deficiency.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 8
    ISSN: 1432-2056
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The seasonal distribution of sympagic amphipods was investigated in the Chesterfield Inlet area of northwestern Hudson Bay (63°30′N). Amphipod abundance was measured by photographic samples and species composition was determined by sweep net samples. Twelve species of amphipods were collected, the most common being Ischyrocerus anguipes, Pontogeneia inermis, Apherusa megalops and Weyprechtia pinguis. The major environmental variable affecting amphipod distribution was water depth. Amphipod abundance was highest near 20 m and near zero past 50 m. The maximum recorded abundance was 1367 m−2. A minor factor affecting the distribution of amphipods was snow depth, through its modifying effect on light and thereby the growth of ice algae. Amphipods began to inhabit the sea ice shortly after its formation. From the beginning of March, the number of amphipods on the ice increased steadily to about the 3rd week of April, after which numbers declined. This pattern coincided with the seasonal ice algae abundance. Amphipods reduced ice algal biomass over 20-m depth by 63%. No evidence of diurnal changes in abundance was observed.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 9
    ISSN: 1432-0878
    Keywords: Inhibin ; Activin ; Testis ; Human ; Macaca fascicularis, Macaca mulatta, Macaca arctoides (Primates)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract The localization and distribution of inhibin/activin subunits was evaluated in the testes of three nonhuman primate species (Macaca fascicularis, M. mulatta, M. arctoides), of young (31 to 43 years) and old (60 to 85 years) men, and of men with disturbed or arrested spermatogenesis using immunohistochemical techniques (peroxidase-anti-peroxidase and alkaline-phosphatase/ anti-alkaline-phosphatase technique). Specific polyclonal (anti-porcine inhibin α-1-32 and anti-bovine activin A) and monoclonal (anti-human inhibin α-1-32 and anti-human activin βA-82-114) antisera were employed. Among all nonhuman primate species and in men, inhibin/activin subunits were present in the cytoplasm of Sertoli cells and Leydig cells but not in germ cells. No relationship could be established between the staining pattern for inhibin/activin subunits and the completeness or the stage of the spermatogenic process. The staining for the βA-subunit in Sertoli cells appeared more intense in the testes of old men compared with that of young men. The majority of Leydig cells contained either the α-subunit and βA-subunit or the βA-subunit alone. The signal for the βA-subunit was remarkably intense in normal and hyperplastic human Leydig cells. These observations demonstrate the presence of inhibin/activin subunits in Sertoli cells and Leydig cells of adult primates and raise the possibility that these subunits or their respective dimers (inhibin A/activin A) might subserve a paracrine/ autocrine role in the adult primate testis. Also, the possibility of specific differences in the α-1-32 subunit and the βA-82-114 subunit region among certain primate species arises from the observation that the monoclonal antisera failed to detect the respective antigens in M. fascicularis and M. mulatta.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 10
    ISSN: 1432-0878
    Keywords: FSH ; Immunohistochemistry ; Receptor mRNA ; In situ hybridization ; Sertoli cell ; Testis ; Human
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Testicular biopsies from 82 oligo-or azoospermic male patients were subjected to immunostaining using anti-human FSH antibodies. Histological evaluation showed normal spermatogenesis (nspg) in 7 (FSH: 2.7±0.7), mixed atrophy (ma) in 63 (FSH:5.3±0.5), and bilateral or unilateral Sertoli Cell Only syndrome (SCO) in 12 (FSH:21.7±3.5) patients. For the relationship between FSH values and testicular histology, see Bergmann et al. (1994). FSH immunoreactivity was found exclusively in Sertoli cells and in some interstitial cells. Seminiferous epithelium showing normal or impaired spermatogenesis displayed only weak immunoreactivity compared to intense immunoreaction, i.e. large and numerous vesicles in Sertoli cells of SCO tubules in biopsies showing mixed atrophy or SCO. In addition, h-FSH receptor mRNA was demonstrated by in situ hydridization using biotinylated cDNA antisense oligonucleotides. Hybridization signals were found within the seminiferous epithelium exclusively in Sertoli cell cytoplasm associated with normal spermatogenesis and in epithelia showing different signs of impairment, including SCO. It is concluded that: (1) Sertoli cells are the only cells within the seminiferous epithelium expressing FSH receptors; (2) the accumulation of FSH immunoreactivity in Sertoli cells of SCO tubules appears to be a sign of impaired Sertoli cell function.
    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...