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  • 11
    Electronic Resource
    Electronic Resource
    Trace element contamination II. Certain pH electrodes (1976)
    Springer
    Bulletin of environmental contamination and toxicology 16 (1976), S. 767-769 
    Details
    ISSN: 1432-0800
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering , Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01685588
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  • 12
    Electronic Resource
    Electronic Resource
    Effects of [CO2] and nitrogen fertilization on soils planted with ponderosa pine (2000)
    Springer
    Plant and soil 224 (2000), S. 99-113 
    Details
    ISSN: 1573-5036
    Keywords: CO2 ; nitrogen fertilization ; soils ; nutrients ; Pinus ponderosa
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The effects of six years treatment with elevated [CO2] (350, 525, and 700 μl l-1) and nitrogen (N) (0, 10, and 20 g N m-2 yr-1) on soils, soil solution, and CO2 efflux in an open-top chamber study with ponderosa pine (Pinus ponderosa Laws.) are described. The clearest [CO2] effect was in year 6, when a pattern of lower soil N concentration and higher C/N ratio with elevated [CO2] emerged. Statistically significant effects of elevated [CO2] on soil total C, extractable P, exchangeable Mg2+, exchangeable Ca2+, base saturation, and soil solution HCO3 - and NO3 - were also found in various treatment combinations and at various times; however, these effects were inconsistent among treatments and years, and in many cases (P, Mg2+, Ca2+, base saturation) reflected pre-treatment differences. The use of homogenized buried soil bags did not improve the power to detect changes in soil C and N or help resolve the inconsistencies in soil C patterns. Nitrogen fertilization had the expected negative effects on exchangeable Ca2+, K+, and Mg2+ in year 6, presumably because of increased NO3 - leaching, but had no consistent effect on soil C, N, or extractable P.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1004781810465
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  • 13
    Electronic Resource
    Electronic Resource
    In vivo evidence for catecholaminergic inhibition of prolactin secretion in the teleostPoecilia latipinna (1976)
    Springer
    Journal of comparative physiology 110 (1976), S. 135-143 
    Details
    ISSN: 1432-136X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Injections of L-dopa in freshwater (FW) fish reduced the size of the prolactin (PRL) cell nuclei, suggesting inhibition of PRL synthesis. A single injection of 6-hydroxydopamine (6-OHDA) in one-third seawater (1/3SW) fish reduced pituitary PRL content and increased PRL cell nuclear size at 6 h and 12 h, indicating stimulation of both synthesis and release of PRL. Two daily injections of 6-OHDA in 1/3SW fish led to PRL cell nuclear enlargement and elevated pituitary PRL content at 48 h after the second injection, indicating strong stimulation of PRL synthesis. Consideration of other parameters (plasma and body sodium levels, plasma osmotic pressure) suggests that the PRL cell responses to 6-OHDA were not mediated by internal osmotic changes. Pretreatment with 6-OHDA also appeared to accelerate the PRL cell activation induced by the transfer of fish from 1/3SW to FW. L-dopa opposed the enhancement of PRL release induced by a single injection of 6-OHDA. Injections of 3,4-dimethoxyphenylethylamine (DMPEA), a specific dopamine antagonist, caused short-term depletion of pituitary PRL, indicating enhanced PRL release. These results suggest that PRL secretion is subject to catecholaminergic inhibition, probably by dopamine. Considering these findings together with previous in vitro results (Wigham et al., 1975), it appears that the PRL cells are innervated by inhibitory catecholaminergic nerve fibres.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00689303
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  • 14
    Electronic Resource
    Electronic Resource
    Quantitative ultrastructural evidence of alterations in prolactin secretion related to external salinity in a teleost fish (Poecilia latipinna) (1977)
    Springer
    Cell & tissue research 185 (1977), S. 129-145 
    Details
    ISSN: 1432-0878
    Keywords: Prolactin cells ; Adenohypophysis ; Teleost (Poecilia latipinna) ; Salinity ; Morphometry ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Quantitative ultrastructural morphometric studies were made on the prolactin cells of Poecilia latipinna adapted to freshwater (FW), one-third seawater (1/3 SW) and full-strength seawater (SW), and at various times after transfers between 1/3 SW and FW. In fully-adapted fish the rates of prolactin (PRL) synthesis and PRL release are inversely related to environmental salinity. During adaptation to a new salinity the two rates are temporarily uncoordinated, with release increasing or decreasing more readily than synthesis. Synthesis appears to take 30 h or longer to come into balance with the increased release rate following transfer from 1/3 SW to FW, and 72 h or longer to adjust to the reduction in release rate that follows the reverse transfer. The excess PRL granules that accumulate in the latter situation appear to be removed by lysosomal digestion. As in other teleosts, in fish adapted to the external medium the size of the stored PRL granules is inversely related to external salinity, but this relationship breaks down during adaptation to a new salinity. The stellate cells which penetrate between the PRL cells are more prominent, more extensively ramified, and appear more metabolically active in FW-adapted fish than in the other groups. These cells seem to be closely related in function to the secretory activity of the PRL cells.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00226674
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  • 15
    Electronic Resource
    Electronic Resource
    Circadian changes in prolactin cell activity in the pituitary of the teleost Poecilia latipinna in freshwater (1976)
    Springer
    Cell & tissue research 165 (1976), S. 267-280 
    Details
    ISSN: 1432-0878
    Keywords: Prolactin cell ; Poecilia latipinna ; Circadian changes ; Morphometry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Quantitative morphometric studies with the electron microscope were made on the prolactin cells of wild freshwater sailfin mollies taken in Florida in August at four different times of day. The results indicate a circadian rhythm in the prolactin cell, the period of highest synthetic activity being from midday to evening, as indicated by the condition of nucleus, Golgi apparatus and rough endoplasmic reticulum, and by the incidence of granule release profiles. No circadian changes were detected in the ACTH cells. Several distinct sites of prolactin granule release were recognised. However, there was no conclusive evidence of granule release by any mechanism other than classical exocytosis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00226664
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  • 16
    Electronic Resource
    Electronic Resource
    Ultrastructure of the adenohypophysis in the teleost Poecilia latipinna (1975)
    Springer
    Cell & tissue research 161 (1975), S. 239-261 
    Details
    ISSN: 1432-0878
    Keywords: Adenohypophysis ; Teleosts (Poecilia, latipinna) ; Cell types ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary In the sailfin molly, Poecilia latipinna, seven morphological endocrine celltypes could be distinguished with the electron microscope. Each of these was identified with one of the seven cell-types distinguished with the light microscope, to most of which endocrine functions have previously been allocated. Corticotrophs and prolactin cells form the rostral pars distalis, and the proximal pars distalis consists of an outer layer of gonadotrophs and an inner zone containing growth hormone cells and thyrotrophs. The pars intermedia contains two cell-types, of uncertain function. Stellate cells (interstitial cells) occur throughout the adenohypophysis, but are most numerous and prominent in the rostral pars distalis. The inner proximal pars distalis contains a cell-type not previously distinguished in this species with the light microscope, the Z-cell, which could be aminergic. The ultrastructural features of each cell-type are described in detail, and discussed in comparisons with the homologous cells described in other teleosts. There is good agreement for different teleosts in the ultrastructural details of each cell type.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00220372
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  • 17
    Electronic Resource
    Electronic Resource
    Ultrastructure of the neurohypophysis of the teleost Poecilia latipinna in relation to neural control of the adenohypophysial cells (1977)
    Springer
    Cell & tissue research 185 (1977), S. 409-433 
    Details
    ISSN: 1432-0878
    Keywords: Neurohypophysis ; Teleost (Poecilia latipinna) ; Axon types ; Hypothalamic control ; Morphometry ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The structure of the neurohypophysis of Poecilia latipinna (green molly, sailfin molly) was studied with the electron microscope. Profile diameters of neurosecretory granules in the non-myelinated neurohypophysial nerve fibres were measured and mathematically corrected for error due to section thickness. Six different types of nerve fibres could be distinguished by statistical classification of their granules and by other ultrastructural features. One fibre-type (type B) contained granules with a mean diameter of 85 nm, and the other five types (types Ala, Alb, A2, A3 and A4) all contained granules with mean diameters greater than 100 nm. Synaptic contacts were observed between type B fibres and all the adenohypophysial cell-types, although in the case of the ACTH cells the synapses were separated from the cell membrane by a continuous double basement membrane. Type A fibres were observed to contact the cells of the proximal pars distalis and pars intermedia, but did not form synapses. However, synapses occurred between type A fibres and pituicytes, and between type A fibres and the pericapillary basement membrane in the interior of the neurohypophysis. The possible roles of the different types of nerve fibres in controlling the adenohypophysial cells are discussed in the context of evidence from other teleosts.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00220300
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