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  • 1
    Electronic Resource
    Electronic Resource
    Bemerkungen über einige afrikanischeTimaliiden des Berliner Muscums (1882)
    Springer
    Journal of ornithology 30 (1882), S. 344-347 
    Details
    ISSN: 1439-0361
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02004099
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  • 2
    Electronic Resource
    Electronic Resource
    Soil, plant and atmospheric conditions as they relate to ammonia volatilization (1995)
    Springer
    Nutrient cycling in agroecosystems 42 (1995), S. 149-158 
    Details
    ISSN: 1573-0867
    Keywords: Micrometeorology ; N flux ; livestock waste ; NH3 ; 15N
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Gaseous ammonia (NH3) transport is an important pathway in the terrestrial N cycle. In the atmosphere NH3 neutralizes airborne acids and is a major factor determining air quality and acid rain deposition patterns. Redeposition of atmospheric NH3 plays an important role in the N balance of natural ecosystems and has been implicated in forest decline, plant species change and eutrophication of surface water. Much of the N in soil-plant animal systems can be lost to the atmosphere, particularly with surface applied livestock waste, or urea and anhydrous ammonia fertilizers. Plants can have a significant impact on NH3 transport because they can both absorb and desorb atmospheric NH3. Under conditions of low soil N or high atmospheric NH3 concentrations, plants absorb NH3. Under conditions of high soil N or low atmospheric NH3 concentrations, plants volatilize NH3. This article discusses methods for evaluating NH3 transport in the filed, the rate of NH3 volatilized from fertilizer application, and the effects of plants on net NH3 transport.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00750509
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  • 3
    Electronic Resource
    Electronic Resource
    Sulfur isotope characteristics of the Archean Cu–Zn Gossan Hill VHMS deposit, Western Australia (2000)
    Springer
    Mineralium deposita 35 (2000), S. 533-550 
    Details
    ISSN: 1432-1866
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences
    Notes: Abstract Gossan Hill is an Archean (∼3.0 Ga) Cu–Zn–magnetite-rich volcanic-hosted massive sulfide (VHMS) deposit in the Yilgarn Craton of Western Australia. Massive sulfide and magnetite occur within a layered succession of tuffaceous, felsic volcaniclastic rocks of the Golden Grove Formation. The Gossan Hill deposit consists of two stratigraphically separate ore zones that are stratabound and interconnected by sulfide veins. Thickly developed massive sulfide and stockwork zones in the north of the deposit are interpreted to represent a feeder zone. The deposit is broadly zoned from a Cu–Fe-rich lower ore zone, upwards through Cu–Zn to Zn–Ag–Au–Pb enrichment in the upper ore zone. New sulfur isotope studies at the Gossan Hill deposit indicate that the variation is wider than previously reported, with sulfide δ34S values varying between −1.6 and 7.8‰ with an average of 2.1 ± 1.4‰ (1σ error). Sulfur isotope values have a broad systematic stratigraphic increase of approximately 1.2‰ from the base to the top of the deposit. This variation in sulfur isotope values is significant in view of typical narrow ranges for Archean VHMS deposits. Copper-rich sulfides in the lower ore zone have a narrower range (δ34S values of −1.6 to 3.4‰, average ∼1.6 ± 0.9‰) than sulfides in the upper ore zone. The lower ore zone is interpreted to have formed from a relatively uniform reduced sulfur source dominated by leached igneous rock sulfur and minor magmatic sulfur. Towards the upper Zn-rich ore zone, an overall increase in δ34S values is accompanied by a wider range of δ34S values, with the greatest variation occurring in massive pyrite at the southern margin of the upper ore zone (−1.0 to 7.8‰). The higher average δ34S values (2.8 ± 2.1‰) and their wider range are explained by mixing of hydrothermal fluids containing leached igneous rock sulfur with Archean seawater (δ34S values of 2 to 3‰) near the paleoseafloor. The widest range of δ34S values at the southern margin of the deposit occurs away from the feeder zone and is attributed to greater seawater mixing away from the central upflow zone.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s001260050260
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  • 4
    Electronic Resource
    Electronic Resource
    Stimulatory effect of follicle-stimulating hormone on rat Leydig cells (1985)
    Springer
    Cell & tissue research 239 (1985), S. 405-415 
    Details
    ISSN: 1432-0878
    Keywords: Testis ; Leydig cell ; FSH ; Morphometry ; Ultrastructure ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The effects of FSH on the testicular interstitial tissue of immature hypophysectomized rats were studied by comparing morphological changes in Leydig cells with quantitative changes in interstitial tissue histology using morphometric analysis. Three groups of rats received subcutaneous injections of 0.5 ml saline vehicle or 10 μg rFSH or 20 ng oLH (equivalent to the amount of LH known to contaminate the FSH), twice daily for 7 days. Administration of FSH significantly increased testis weight and stimulated more advanced spermatogenesis compared to saline or LH. Morphometric analysis of testes of LH-treated rats showed a small but significant increase in total interstitial cell volume compared to saline treatment. FSH caused much greater increases in the total volume of interstitial tissue and interstitial cells than either saline or LH and significantly increased the total volume of interstitial fluid by comparison with the other groups. FSH but not saline or LH treatment resulted in a striking hypertrophy of Leydig cells, to produce cells ultrastructurally identical to Leydig cells from adults. Since the target tissue of FSH is the seminiferous epithelium, the observed effects on Leydig cells by FSH treatment suggest that the secretion of factors by the seminiferous tubules may mediate the maturation of Leydig cells.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00218021
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  • 5
    Electronic Resource
    Electronic Resource
    Response of the seminiferous epithelium of the rat testis to withdrawal of androgen: evidence for direct effect upon intercellular spaces associated with Sertoli cell junctional complexes (1993)
    Springer
    Cell & tissue research 274 (1993), S. 153-161 
    Details
    ISSN: 1432-0878
    Keywords: Testis ; Sertoli cells ; Testosterone ; Hypophysectomy ; Ethane dimethanesulphonate ; Rat (Sprague-Dawley)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract The morphological response of the Sertoli cells to partial or complete withdrawal of testosterone was studied in adult rats following hypophysectomy or administration of ethane dimethanesulphonate (EDS), a toxicant known to destroy selectively the Leydig cells of the testis. To assess the role of germ cells in effecting changes to Sertoli cells following withdrawal of testosterone, germ cell-deficient rats with Sertoli-cell-only testes (SCO) were treated with EDS to remove the source of testosterone. At 6 days after hypophysectomy or 4,6 and 8 days after EDS treatment, stage VII and VIII seminiferous tubules showed degenerating germ cells and numerous basally-located vacuoles approximately 1–15 μm in diameter. Ultrastructural analysis indicated that most of the vacuoles were multiple focal dilations of the intercellular space associated with Sertoli cell junctional complexes. In SCO rats, treatment with EDS resulted in a significant (P〈0.05) increase in the formation of many vacuoles particularly in the base but also in the trunk of the Sertoli cells and again electron microscopic analysis showed multiple, localized expansions of the intercellular space associated with Sertoli cell junctional complexes. The appearance of intercellular spaces in SCO testes following androgen withdrawal cannot be attributed to shrinkage of degenerating germ cells since the seminiferous tubules did not contain germ cells. It is concluded that withdrawal of androgen induces early morphological alterations of the Sertoli cell junctional complexes in which the sites of membrane fusions representing tight junctions remain intact whereas the intercellular spaces exhibit major focal dilations. The results are discussed in relation to the fluid secretion by the seminiferous tubules which is regulated by the Sertoli cells.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00327996
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  • 6
    Electronic Resource
    Electronic Resource
    Focal disruption of spermatogenesis in the testis of adult rats after a single administration of human chorionic gonadotrophin (1989)
    Springer
    Cell & tissue research 257 (1989), S. 163-169 
    Details
    ISSN: 1432-0878
    Keywords: Testis ; Human chorionic gonadotrophin ; Inflammatory response ; Spermatogenic disruption ; Rat (Sprague-Dawley)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The effect of a single injection of 100 i.u. human chorionic gonadotrophin (hCG) upon the morphology of the rat testis was studied by light and electron-microscopy from 12–48 h after treatment. Twelve hours after injection of hCG, emigration of leukocytes occurred across the intertubular blood vessels and, both at this time and at 24 h, infiltrations of leukocytes were observed within the extracellular tissue spaces. Furthermore, 12 h after hCG, the seminiferous epithelium showed focal disruption of spermatogenesis involving germ cell degeneration and pyknosis. Focal damage to the seminiferous epithelium persisted at 24 h and 48 h after injection of hCG, the affected seminiferous tubules showing failure of spermiation, accumulation of extracellular vacuoles and degeneration or partial loss of spermatogonia and primary spermatocytes. The observations show that, after stimulation of the Leydig cells with hCG, the intertubular tissue exhibits an inflammatory-type response and this is associated with focal tissue destruction in the seminiferous tubules. It is concluded that a high dose of hCG exerts anti-spermatogenic effects upon the testis and raises the possibility of unexpected interference with tests of normal Leydig cell function in both laboratory and clinical investigations.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00221647
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  • 7
    Electronic Resource
    Electronic Resource
    Macrophages in the interstitial tissue of the rat testis (1986)
    Springer
    Cell & tissue research 243 (1986), S. 337-344 
    Details
    ISSN: 1432-0878
    Keywords: Macrophages ; Leydig cells ; Testis ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Macrophages were identified in the intertubular tissue of the rat testis by loading animals with a particulate vital dye (trypan blue or India ink) and by localizing immunocytochemically a macrophage membrane antigen (MRC W3/25). Leydig cells were identified by the histochemical staining reaction for 3β-hydroxysteroid dehydrogenase activity and by a monoclonal antibody. Macrophages were scattered in the interstitial tissue closely attached to and mixed with the Leydig cells. They were never found in the seminiferous tubules. The macrophages comprised about 25% of all the cells in the interstitium. Double staining with a vital dye and a marker antibody showed that all the phagocytosing cells were macrophages and that the Leydig cells did not take up vital dyes. Double staining for the demonstration of the 3β-hydroxysteroid dehydrogenase activity and the macrophage antigen likewise revealed two distinctly different cell populations. Crude Leydig cell preparations obtained by collagenase treatment of the testis contained macrophages (12–14%). Macrophages were present throughout the postnatal prepuberal development of the testis. Their density was increased in the cryptorchid and irradiated testis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00251049
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  • 8
    Electronic Resource
    Electronic Resource
    Origin of regenerating Leydig cells in the testis of the adult rat (1987)
    Springer
    Cell & tissue research 249 (1987), S. 367-377 
    Details
    ISSN: 1432-0878
    Keywords: Ethane dimethanesulphonate ; Leydig cells ; Destruction ; Regeneration ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Ethane dimethanesulphonate (EDS) was used as a specific cytotoxin to eliminate the Leydig cell population of the adult rat testis. Ultrastructural, morphometric and serum gonadotrophin and testosterone analysis was used to study the response of the intertubular tissue of the testis from 1 day to 10 weeks after EDS treatment. In control animals, the testis contained approximately 28 million Leydig cells and 8 million macrophages. Three to seven days after EDS treatment, Leydig cells were absent and serum testosterone was undetectable. Macrophage numbers increased three-fold by 3 days and returned to pretreatment values thereafter. At 2 and 3 weeks post-EDS, foetal-type Leydig cells (∼1–2 million per testis) appeared in proximity to perivascular and peritubular tissues, a feature also observed at 4 weeks when numerous such cells (∼15 million per testis) formed prominent clusters in perivascular and peritubular locations. Between 6 and 10 weeks after EDS treatment, the foetal-type Leydig cells were transformed morphologically into adult-type Leydig cells, they occupied central intertubular positions and their numbers were restored to pretreatment values. Regeneration of Leydig cells was reflected by elevated serum testosterone levels which returned towards the normal range. The results demonstrate the regenerative capacity of the testicular intertubular tissue and indicate a dual site of origin of Leydig cells which initially resemble foetal-type Leydig cells prior to establishing the adult-type Leydig cell population. The morphological pattern of Leydig cell regeneration suggests that in addition to gonadotrophic stimulation, local testicular factors from the seminiferous tubules may stimulate Leydig cell growth.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00215521
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  • 9
    Electronic Resource
    Electronic Resource
    Testosterone and FSH have independent, synergistic and stage-dependent effects upon spermatogenesis in the rat testis (1992)
    Springer
    Cell & tissue research 268 (1992), S. 179-189 
    Details
    ISSN: 1432-0878
    Keywords: Testis ; Spermatogenesis ; FSH ; Testosterone ; Rat (Sprague-Dawley)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Adult rats were hypophysectomized and treated with ethane dimethanesulphonate (EDS) selectively to eliminate the Leydig cells in the testis. By removing the source of endogenous gonadotrophins and androgens, the subsequent effects on the seminiferous epithelium were studied after 20 days of treatment with vehicle, or FSH (2x50 μg/day) or a low dose of testosterone (0.6 mg testosterone esters every 3rd day) alone or in combination. Compared to vehicle-treated hypophysectomized rats with Leydig cells, testis weight in saline-treated hypophysectomized rats treated with EDS declined by 50%, spermatogenesis was disrupted severely and only 18% of the tubules contained spermatids, these being confined to stages I–VI of the spermatogenic cycle. Treatment with either FSH or testosterone esters alone significantly (P〈0.01) increased testis weight compared to vehicle-treated hypophysectomized rats treated with EDS and 40% of tubules contained spermatids either at stages I–VI after FSH, or at all stages I–XIV after testosterone treatment. Treatment with FSH and testosterone esters together maintained testis weights approximately 20% above vehicle-treated hypophysectomized controls; over 70% of the seminiferous tubules contained spermatids and there was a marked stimulation of spermatogenesis at all stages of the spermatogenic cycle. The results suggest, that in the absence of the pituitary gland and the Leydig cells, FSH alone partially supports spermatogenesis up to the development of round spermatids whereas testosterone is capable of maintaining spermatid development at all 14 stages of the cycle. When FSH and testosterone were administered in combination, the effects upon spermatogenesis were far greater than the response expected if their individual effects were simply additive. It is therefore concluded that FSH may play a role in normal spermatogenesis and that this role is essentially that of augmenting the response of the testis to testosterone. The biochemical mechanisms via which this might occur are discussed and hypophysectomized rats treated with EDS used in the present studies should provide a useful approach for their identification.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00338067
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  • 10
    Electronic Resource
    Electronic Resource
    Cellular localisation of messenger RNAs in rat testis: application of digoxigenin-labelled ribonucleotide probes to embedded tissue (1993)
    Springer
    Cell & tissue research 273 (1993), S. 269-277 
    Details
    ISSN: 1432-0878
    Keywords: Spermatogenesis ; Cyclic protein 2 ; Transition protein 2 ; Cytochrome c oxidase ; Sertoli cell ; Spermatids ; Pachytene spermatocytes ; Rat (Wistar)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract In an attempt to identify key changes involved in normal spermatogenesis we have developed methods to enable the study of gene expression by the various subpopulations of testicular cells by use of in-situ hybridisation histochemistry. The use of digoxigenin-labelled ribonucleotide and oligonucleotide probes on testicular tissue perfusion-fixed with Bouin's fixative and embedded in paraffin, polystyrene or methacrylate, has been used to accurately localise three transcripts to three different cell types (Sertoli cells, pachytene spermatocytes, and step 7–12 spermatids) within the seminiferous tubule. The ability to produce semi-thin sections of polystyrene- or methacrylate-embedded tissue and successfully to apply digoxigenin-labelled ribonucleotide or oligonucleotide probes resulted in far greater resolution and unequivocal localisation of mRNA in testicular cells than was previously possible by use of thicker paraffin or frozen sections hybridised with 35S-labelled riboprobes. A comparison of the different embedding media versus digoxigenin-labelled oligonucleotide or ribonucleotide probes is made and we demonstrate the relative sensitivities and merits of each combination.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00312828
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