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  • 1
    Electronic Resource
    Electronic Resource
    Long-term depletion of calcium and other nutrients in eastern US forests (1989)
    Springer
    Environmental management 13 (1989), S. 593-601 
    Details
    ISSN: 1432-1009
    Keywords: Acid precipitation ; Biomass nutrients ; Calcium ; Clearcutting ; Magnesium ; Nitrogen ; Phosphorus ; Potassium ; Soil leaching ; Soil nutrients ; Timber harvest ; Weathering ; Whole-tree harvest
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract Both harvest removal and leaching losses can deplete nutrient capital in forests, but their combined long-term effects have not been assessed previously. We estimated changes in total soil and biomass N, Ca, K, Mg, and P over 120 years from published data for a spruce-fir site in Maine, two northern hardwood sites in New Hampshire, central hardwood sites in Connecticut and Tennessee, and a loblolly pine site in Tennessee. For N, atmospheric inputs counterbalance the outputs, and there is little long-term change on most sites. For K, Mg, and P, the total pool may decrease by 2%–10% in 120 years depending on site and harvest intensity. For Ca, net leaching loss is 4–16 kg/ha/yr in mature forests, and whole-tree harvest removes 200–1100 kg/ha. Such leaching loss and harvest removal could reduce total soil and biomass Ca by 20%–60% in only 120 years. We estimated unmeasured Ca inputs from rock breakdown, root-zone deepening, and dry deposition; these should not be expected to make up the Ca deficit. Acid precipitation may be the cause of current high leaching of Ca. Although Ca deficiency does not generally occur now in acid forest soils, it seems likely if anthropogenic leaching and intensive harvest removal continue.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01874965
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  • 2
    Electronic Resource
    Electronic Resource
    Effects of calcium input/output on the stability of a system for calcium-regulated viscoelastic strain fields (1990)
    Springer
    Journal of mathematical biology 28 (1990), S. 585-593 
    Details
    ISSN: 1432-1416
    Keywords: Calcium ; Viscoelasticity ; Stability ; Pattern generation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Mathematics
    Notes: Abstract The Goodwin and Trainor model of pattern generation in calcium-regulated strain fields is studied in the case where calcium input and calcium output processes are involved. It is shown that the properties of the original model may still remain provided that the input-output processes are not unstable. In this last case, despite the eventual stabilizing effect of the calcium exchange term, perturbations of the generalized system can grow and lead to inhomogeneous solutions. Applications to cell differentiation and cell growth are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00164164
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  • 3
    Electronic Resource
    Electronic Resource
    Triton channels are sensitive to divalent cations and protons (1994)
    Springer
    The journal of membrane biology 141 (1994), S. 83-90 
    Details
    ISSN: 1432-1424
    Keywords: Phospholipid bilayers ; Triton X-100 ; Ion channels ; Calcium ; Zinc ; Protons
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Addition of Triton X-100 to planar bilayers composed of dioleoyl phosphatidyl choline, diphytanoyl phosphatidyl choline or mono-oleoyl glycerol induces single channel-like events when electrical conductivity across the bilayer is measured. Addition of divalent cations or protons causes channels to disappear; single channel conductance of remaining channels is not significantly altered; addition of EDTA or alkali (respectively) reverses the effect. It is concluded that sensitivity to divalent cations and protons need not be dependent on specific channel proteins or pore-forming toxins, but may be a feature of any aqueous pore across a lipid milieu.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00232876
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  • 4
    Electronic Resource
    Electronic Resource
    The effect of insulin on bone resorption (1973)
    Springer
    Calcified tissue international 12 (1973), S. 8-15 
    Details
    ISSN: 1432-0827
    Keywords: Insulin ; Bone ; Calcium ; Resorption ; Orthophosphate
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Description / Table of Contents: Résumé L'administration d'insuline cristallisée à des rats thyroparathyroidectomisés provoque une augmentation de la calcémie et de la phosphorémie. Le calcium plasmatique s'élève de façon linéaire entre 31 et 250 m Unités d'insuline/100 g de poids corporel. La courbe obtenue n'est guère différente de celle obtenue par extrait parathyroidien. L'administration simultanée d'insuline et d'extrait parathyroidien à des rats thyro-parathyroidectomisés agit sur la calcémie et la phosphorémie par un effet additif. Lorsque des os frontaux d'embryons de poulet sont cultivésin vitro en présence d'insuline cristallisée, le taux de résorption augmente. L'insuline augmente le taux de consommation en glucose des explants et induit une accumulation de citrate dans le milieu de culture. L'insuline stimule donc la résorption osseuse.
    Abstract: Zusammenfassung Der Plasmagehalt an Calcium und Phosphor bei thyroparathyreoidektomierten Ratten wurde durch die Verabreichung von kristallinem Insulin erhöht. Das Plasmacalcium verhielt sich zwischen 31 und 250 m Einheiten Insulin pro 100 g Körpergewicht linear. Die Steigung der erhaltenen Kurve ist nicht signifikant verschieden von derjenigen, die nach Parathyreoidea-Extrakt erhalten wird. Die gleichzeitige Verabreichung von Insulin und Parathyreoidea-Extrakt von thyroparathyreoidektomierten Ratten hatte eine kumulative Wirkung auf den Gehalt von Calcium und Phosphor im Plasma. Wenn Stirnbeine von Kükenembryos mit kristallinem Insulinin vitro kultiviert wurden, erhöhte sich die Resorptionsrate. Das Insulin steigerte den Glucoseverbrauch der Explantate und verursachte eine Anreicherung von Citrat im Kulturmedium. Die Ergebnisse deuten auf eine Stimulation der Knochenresorption durch Insulin.
    Notes: Abstract the administration of crystalline insulin to thyroparathyroidectomized rats raised their calcium and phosphorus plasma levels. The plasma calcium gave a linear response between 31 and 250 mU of insulin/100 g body weight. The slope obtained is not significantly different from that obtained with parathyroid extract. The simultaneous administration of insulin and parathyroid extract to thyroparathyroidectomized rats affected the calcium and phosphorus plasma levels in an additive fashion. When chick embryo frontal bones were cultivatedin vitro with crystalline insulin the rate of resorption increased. Insulin increased the rate of glucose consumption by the explants and induced the accumulation of citrate in the culture medium. It is concluded that insulin stimulates bone resorption.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02013717
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  • 5
    Electronic Resource
    Electronic Resource
    Interleukin-1 receptor antagonist inhibits calcium accumulation in in vivo chronic granuloma induced by potassium permanganate (1993)
    Springer
    Calcified tissue international 52 (1993), S. 300-304 
    Details
    ISSN: 1432-0827
    Keywords: Interleukin 1 ; Calcium ; Inflammation ; Granuloma ; Potassium permanganate
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary Interleukin-1 (IL-1) is a monokine that exerts multiple biological activity, including immunity and inflammation. Moreover, IL-1 is involved in Ca2+ release causing hypercalcemia and bone resorption. Recently, a 22 kDa natural inhibitor to IL-1 called interleukin-1 receptor antagonist (IL-1ra) has been described in human fluids, which specifically binds IL-1α or IL-1β receptors. In this study, we found that experimental granuloma induced by subcutaneous injections (0.2 ml) of potassium permanganate (KMnO4) 1:40 saturated crystal solution, after 7 days was strongly inhibited in size, weight and calcium content (measured as dry ash weight by incineration of granuloma tissue) compared with untreated controls, in mice treated intraperitoneally with IL-1ra (20 μg/bolus) given twice; the first at the same time of the induction of the granuloma and the second 24 hours later. In addition, leukotriene B4 and prostaglandin E2 were also inhibited in fresh granuloma of mice treated with IL-1ra. Taken together, these findings conclude for the first time, that the accumulation of calcium in chronic inflammatory states is strongly inhibited by IL-1ra, which decreases tissue calcergy and can potentially be useful for the treatment of calcium-related inflammatory diseases and malignancy-associated hypercalcemia.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00296655
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  • 6
    Electronic Resource
    Electronic Resource
    Relationship between iron, calcium and phosphate during experimental cutaneous calcinosis (1969)
    Springer
    Calcified tissue international 4 (1969), S. 224-230 
    Details
    ISSN: 1432-0827
    Keywords: Calcinosis ; Calcium ; Iron ; Phosphate ; Collagen
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Description / Table of Contents: Résumé La calcification de la peau (calciphylaxie) provoquée par l'administration sous-cutanée de chlorure de fer chez des rats sensibilisés par le dihydrotachystérol (DHT) est précédée par une déposition sélective de fer (décelable à la microscopie électronique) à la surface des fibres collagènes. Les analyses à la microsonde prouvent que les taux de calcium et de phosphore sont augmentés à l'endroit de l'injection du chlorure de fer même sans l'administration préalable de DHT; cependant, l'apatite ne se forme que chez les animaux prétraités par le DHT. La quantité et le degré de cristallinité de la matière inorganique sont presque identiques au sixième et au trentième jour de l'expérience.
    Abstract: Zusammenfassung Durch elektronenmikroskopische Untersuchungen wurde festgestellt, daß die durch subcutane Verabreichung von Eisenchlorid bei Dihydrotachysterin-sensibilisierten Ratten herbeigeführte Hautverkalkung durch eine selektive Eisenablagerung auf der Oberfläche der Kollagenfibrillen eingeleitet wird. Die Röntgenmikroanalyse zeigt an, daß die lokale Calciumund Phosphorkonzentration bereits nach Eiseninjektion allein ansteigt, während Apatitbildung nur in den mit DHT vorbehandelten Tieren erfolgt. Ausmaß und Menge der Kristallisation sind am 6. und 30. Tage nach Versuchsbeginn fast gleich.
    Notes: Abstract Calcification of the skin (calciphylaxis) induced by the subcutaneous administration of iron chloride to dihydrotachysterol (DHT)-sensitized rats is preceded by the selective deposition of iron (visible with electron microscopic techniques) on the surface of collagen fibrils. Electron probe X-ray microanalysis indicates that the injectionof iron alone suffices to increase local concentrations of calcium and phosphorus; however, apatite formation occurs only in animals pretreated with DHT. The amount and degree of crystallinity of the inorganic material is very similar on the sixth and thirtieth day after the beginning of the experiment.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02279125
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  • 7
    Electronic Resource
    Electronic Resource
    Lack of effect of dietary minerals on liver cholesterol concentrations in rats (1989)
    Springer
    European journal of nutrition 28 (1989), S. 316-318 
    Details
    ISSN: 1436-6215
    Keywords: dietarycalcium ; dietarymagnesium ; dietaryphosphorus ; serumcholesterol ; livercholesterol ; fecalbile acids ; rats ; Calcium ; Magnesium ; Phosphor ; Serumcholesterin ; Lebercholesterin ; Gallensäure im Kot ; Ratten
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Medicine
    Description / Table of Contents: Zusammenfassung Während 28 Tagen wurden an Ratten cholesterinfreie halbgereinigte Diäten, die verschiedene Konzentrationen von Calcium (0,13–0,75 g/100 g), Magnesium (0,02–0,04 g/100 g) oder Phosphor (0,2–0,8 g/100 g) enthielten, verabreicht. Die unterschiedlichen Mineralkonzentrationen hatten keinen Einfluß auf Serum- und Lebercholesterin oder die Ausscheidung von Gallensäuren im Kot.
    Notes: Summary Female rats were fed cholesterol-free, purified diets with different concentrations of calcium (0.13–0.75%, w/w), magnesium (0.02 or 0.04%) or phosphorus (0.2–0.8 %) as the only dietary variable. After 28 days, no effects of the minerals were found on liver cholesterol concentrations and rates of fecal excretion of bile acids.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02019394
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  • 8
    Electronic Resource
    Electronic Resource
    Effects of waterlogging on young wheat plants (Triticum aestivum L.) and on soil solutes at different soil temperatures (1982)
    Springer
    Plant and soil 69 (1982), S. 311-326 
    Details
    ISSN: 1573-5036
    Keywords: Aeration ; Calcium ; Carbon dioxide ; Ethylene ; Nitrate ; Nitrite ; Nitrous oxide ; Oxygen ; Potassium ; Roots ; Triticum aestivum ; Waterlogging ; Wheat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary We report a study of the mechanism by which the response of plants to waterlogging can be modified by soil temperature. Wheat was grown initially in well-aerated soil in a controlled environment room before the soil was flooded with aerated, deionized water. The soil temperature was maintained constant in the range 6–18°C while the air temperature was at 14°C. Waterlogging damage was greater in plants at the higher soil temperatures when the plants were compared at the same chronological age. However, when compared at the same growth stage, the response to soil temperature was little differenti.e. plants subjected to waterlogging for a long time at low soil temperatures exhibited a similar reduction in growth and other properties as those subjected briefly at higher temperatures. The concentration of dissolved oxygen in the soil solution declined rapidly at all temperatures, being almost zero after 36 h waterlogging. Temperature affected rates of change of the concentrations of dissolved carbon dioxide, ethylene, nitrous oxide, nitrite, nitrate, calcium and potassium. The importance of soil-and plant-determined properties in the waterlogging response of plants at different temperatures are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02372453
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  • 9
    Electronic Resource
    Electronic Resource
    The intracellular events triggered by the self-incompatibility response inPapaver rhoeas (1999)
    Springer
    Protoplasma 208 (1999), S. 99-106 
    Details
    ISSN: 1615-6102
    Keywords: Papaver rhoeas ; Self-incompatibility ; Calcium ; Signal transduction ; Cell-cell recognition
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary In recent years self-incompatibility (SI) has come to be recognised as an important model system for studying cell-cell interactions and signalling in flowering plants. In this article we discuss the intracellular events associated with the SI response in the field poppy,Papaver rhoeas. The SI response inP. rhoeas is known to involve a Ca2+-based signalling pathway, activated following molecular interactions on the surface of incompatible pollen tubes. Evidence demonstrates that, following a transient increase in the concentration of cytosolic free Ca2+ ([Ca2+];) initiated by the SI response, phosphorylation of certain cytosolic proteins occurs, followed by activation of pollen gene expression. The magnitude of this transient Ca2+ wave and the localisation of cytosolic [Ca2+]i following the SI response are discussed. We also describe the character of the proteins specifically phosphorylated in the SI response and the nature of the protein kinases involved in their phosphorylation. Finally, we consider the possibility that the end result of the SI response inP. rhoeas may be analogous to programmed-cell-death mechanisms such as those seen in developmental processes and defence responses in various plant cells.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01279079
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  • 10
    Electronic Resource
    Electronic Resource
    Distribution of the anionic sites in the cell wall of apple fruit after calcium treatment (1994)
    Springer
    Protoplasma 178 (1994), S. 156-167 
    Details
    ISSN: 1615-6102
    Keywords: Calcium ; Cationic gold ; Cell wall ; Fruit ; Pectin ; Ripening
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The ripening and softening of fleshy fruits involves biochemical changes in the cell wall. These changes reduce cell wall strength and lead to cell separation and the formation of intercellular spaces. Calcium, a constituent of the cell wall, plays an important role in interacting with pectic acid polymers to form cross-bridges that influence cell wall strength. In the present study, cationic colloidal gold was used for light and electron microscopic examinations to determine whether the frequency and distribution of anionic binding sites in the walls of parenchyma cells in the apple were influenced by calcium, which was pressure infiltrated into mature fruits. Controls were designed to determine the specificity of this method for in muro labelling of the anionic sites on the pectin polymers. The results indicate that two areas of the cell wall were transformed by the calcium treatment: the primary cell walls on either side of the middle lamella and the middle lamella intersects that delineate the intercellular spaces. The data suggest that calcium ions reduce fruit softening by strengthening the cell walls, thereby preventing cell separation that results in formation of intercellular spaces.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01545965
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