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  • Calcium  (7)
  • Salinity  (5)
  • Lepidoptera
  • healthy volunteers
  • Springer  (15)
  • 2005-2009
  • 1980-1984  (15)
  • 1965-1969
  • 1980  (15)
Collection
Keywords
Publisher
  • Springer  (15)
Years
  • 2005-2009
  • 1980-1984  (15)
  • 1965-1969
Year
  • 1
    Electronic Resource
    Electronic Resource
    Rhythmic dentinogenesis in the rabbit incisor: Allometric aspects (1980)
    Springer
    Calcified tissue international 32 (1980), S. 45-53 
    Details
    ISSN: 1432-0827
    Keywords: Dentin ; Periodicity ; Allometry ; Calcium ; Sulfur
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary We have described differences in the aspects of biological rhythms for calcium and sulfur deposition on the labial and lingual sides of the growing rabbit incisor, where growth occurs along a spiral axis. The calcium oscillations appear to be smoother on the labial side than on the lingual side. The lingual side is characterized by high-frequency rhythms with high amplitudes which possess the greatest percent of the power (Fourier analysis). These observations also reflect a difference in behavior of the mean Ca concentration across the labial and lingual sides. Sulfur rhythms on the labial side have higher amplitudes than those on the lingual side, but systematic differences in distribution of power between high and low frequencies is not as pronounced as in the case of Ca. The differences in Ca rhythms reflect differences in the growth rates of incisors on either side of the spiral axis. The labial side grows slightly faster than the lingual side, and its odontoblasts secrete Ca along the spiral axis and toward the pulp cavity at the same time. Thus the resultant direction of growth is more nearly opposite the extension of the occlusal end on the labial side, and Ca is consequently deposited over a wider area relative to that on the lingual surfaces. On the lingual side, Ca is deposited within a more limited area, and growth must therefore be continuous at high frequencies. The distribution of Ca on both sides of the tooth reflects these differences in growth rate and periodicity in two ways. First, given a unit area of tooth, the calcium concentration on the labial side is less than that of the lingual side. Second, whereas the calcium concentration on the labial side declines rapidly from the enamel-dentin junction to the pulp cavity, it is uniformly high across the lingual side because its growth is more continuous at high frequencies.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02408520
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  • 2
    Electronic Resource
    Electronic Resource
    Rhythmic dentinogenesis in the rabbit incisor: Circadian, ultradian, and infradian periods (1980)
    Springer
    Calcified tissue international 32 (1980), S. 29-44 
    Details
    ISSN: 1432-0827
    Keywords: Rabbit ; Dentin ; Calcium ; Sulfur ; Periodicity ; Circadian ; Ultradian
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary We have identified a variety of biological rhythms involved in the apposition and mineralization of dentin in the rabbit incisor. Animals were injected during the day or night with lead acetate at 2-week intervals—to provide biological time markers in forming dentin—and transverse undecalcified sections of the lower incisors were prepared for electron microprobe analysis. The positions of the lead markers were identified, and the continuous distribution of calcium and sulfur was measured at 1 µm intervals between the markers. In thin sections stained with hematoxylin after decalcification, the widths of a series of structural increments (bands) were measured with an ocular micrometer. Fourier analysis of the data revealed spectra of structural and compositional rhythms with a range of periodicities which extended from a matter of hours [ultradian (〈24 h)] to days [infradian (〉24 h) and circadian (approximately 24 h)]. The structural and compositional rhythms appeared to be independent to the extent that they did not necessarily have the same periods, or amplitudes. Nor were there simple phase relationships between all of the rhythms. At some times, Ca and S fluctuations are inversely proportional (180° out of phase), but in other cases they are directly proportional or out of phase by varying degrees other than 180°. The analyses thus suggest that calcium and sulfur deposition (representing mineral and glycosaminoglycan deposition, respectively) are not simply inversely proportional, and that the hematoxylin-stained structural increments did not solely reflect differences in the distribution of the mineral components in dentin.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02408519
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  • 3
    Electronic Resource
    Electronic Resource
    Effects of a bone resorptive factor from human cancer ascites fluid on rat bone cell calcium and cyclic AMP (1980)
    Springer
    Calcified tissue international 30 (1980), S. 191-197 
    Details
    ISSN: 1432-0827
    Keywords: Bone cells ; Cyclic AMP ; Calcium ; Ascites fluid resorptive protein
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary The effects of a bone resorptive protein isolated from human cancer ascites fluid on bone cell calcium and cyclic AMP were studied with fetal rat cells. The osteoclast-activating factor increased bone cell calcium uptake at 37°C and 4°C with no direct effects on calcium efflux. Concentrations of the resorptive factor that increased in vitro bone resorption and cell calcium uptake had no effect on cyclic AMP. The effects of the protein on calcium uptake were not specific for bone cells, and large increases were also observed in isolated fetal rat skin cells. These studies suggest that increases in the permeability of the cell membrane to calcium are involved in the mechanism of action of the ascites fluid resorptive protein.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02408627
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  • 4
    Electronic Resource
    Electronic Resource
    Effects of pyrophosphate and diphosphonates on the dissolution of hydroxyapatites using a flow system (1980)
    Springer
    Calcified tissue international 31 (1980), S. 153-159 
    Details
    ISSN: 1432-0827
    Keywords: Hydroxyapatite ; Dissolution ; Pyrophosphate, Diphosphonates ; Calcium ; Phosphate
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary Pyrophosphate and diphosphonate ions have been said to diminish the dissolution of hydroxyapatite crystals, because they lower the equilibrium concentrations of calcium and phosphate ions in the bulk solution around hydroxyapatite crystals in a closed system. However, in a closed system these effects are not necessarily due to an effect on dissolution alone. In this paper we have used a continuous flow system to study the effects of pyrophosphate and two diphosphonates, ethane-1-hydroxy-1,1-diphosphonate and dichloromethane diphosphonate, on the dissolution of hydroxyapatite. All three compounds decreased markedly the rate of dissolution of hydroxyapatite as well as the exchangeable pools of calcium and phosphate ions around the cystals.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02407176
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  • 5
    Electronic Resource
    Electronic Resource
    Effects of 1α-hydroxy vitamin D3 on the rachitic chick intestine: A comparison to the effects of 1,25-dihydroxyvitamin D3 (1980)
    Springer
    Calcified tissue international 32 (1980), S. 9-17 
    Details
    ISSN: 1432-0827
    Keywords: 1α-Hydroxy vitamin D3 ; 1,25-Dihydroxyvitamin D3 ; Calcium ; Transport ; Intestine
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary The timed sequence of events following the oral administration of 1α-hydroxy vitamin D3 (1αOHD3) to rachitic chicks was compared to that following a comparable dose of 1α,25-dihydroxyvitamin D3 (1,25(OH)2D3). RNA polymerase activity was maximally increased 20% by 1αOHD3 within 1 to 2 h and returned to control values after 8 h. Alkaline phosphatase activity was stimulated by 4 h and was maximal (3- to 5-fold increase) at 24 h. Calcium binding protein (CaBP) was detected initially within epithelial cells at the proximal end of the villus (just above the crypt) 6 to 8 h after 1αOHD3 administration, in epithelial cells lining the proximal half of the villus by 24 h, and in epithelial cells along nearly the entire villus by 48 h. At no time did goblet cells contain CaBP. Serum calcium concentrations were significantly elevated in 2 h and maximal by 12 h (an increase of 3.6 mg/dl). Calcium accumulation by the intestinal mucosa in vitro was increased by 6 to 8 h and maximal (60% increase over controls) at 24 h. Phosphate accumulation by the intestinal mucosa in vitro was increased by 6 h and maximal (105% increase over controls) between 8 and 24 h. 1,25(OH)2D3 increased CaBP and calcium accumulation by 4 h, 2 h sooner than did 1αOHD3. 1,25(OH)2D3 decreased serum calcium levels and increased serum phosphate levels at 2 h unlike 1αOHD3. No difference in the effects of these compounds on alkaline phosphatase activity, RNA polymerase activity, and phosphate accumulation could be demonstrated. These results are consistent with the possibility that 1αOHD3 may not require conversion to 1,25(OH)2D3 for all of its biological effects.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02408517
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  • 6
    Electronic Resource
    Electronic Resource
    Ultrastructural localization of calcium in the mandibular condylar growth cartilage of the rat (1980)
    Springer
    Calcified tissue international 30 (1980), S. 27-34 
    Details
    ISSN: 1432-0827
    Keywords: Ultrastructure ; Calcium ; Cartilage ; Vesicles
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary The potassium pyroantimonate technique was utilized for the selective subcellular localization of calcium in the mandibular condylar cartilage of 1-day-old rats. Electron dense calcium pyroantimonate precipitates were localized principally in mitochondria and at the cell membrane of the chondrocytes. In addition, small intracellular vesicles 0.1–0.2µm in diameter were observed in proximity to the cell membrane of chondrocytes of the mid-hypertrophic zone. The results suggest that these vesicles were being extruded from the cell into the extracellular matrix. Energy-dispersive analysis by X-rays confirmed that calcium is the principal cation of the electron-dense precipitates.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02408603
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  • 7
    Electronic Resource
    Electronic Resource
    Evaluation of a radioreceptor assay for beta-adrenoceptor antagonists in plasma (1980)
    Springer
    European journal of clinical pharmacology 17 (1980), S. 349-354 
    Details
    ISSN: 1432-1041
    Keywords: propranolol ; radioreceptor assay ; beta-adrenoceptor antagonists ; lung membranes ; plasma level ; healthy volunteers
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary A radioreceptor assay (RRA) recently developed in this laboratory for beta-adrenoceptor antagonists in plasma was evaluated in normal volunteers and compared with a radioimmunoassay (RIA) for propranolol. The RRA depends upon the ability of beta-adrenoceptor antagonists to compete with a radiolabelled ligand for beta-adrenoceptor binding sites on lung membranes. Unlike other assays, it measures biologically active drugs including active metabolites of the parent compound. In volunteers given a single oral dose of (±)-propranolol, considerable differences between the two assay methods were demonstrated. In other experiments this difference was shown to relate to the RIA's sensitivity to the inactive (+)-isomer of propranolol and possibly to inactive metabolites. The facility of the RRA in measuring plasma levels of several other non-selective beta-adrenoceptor antagonists was also demonstrated. By employing (−)-propranolol as the standard in the RRA, all of these drugs can be directly compared with a single and relatively simple assay technique.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00558447
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  • 8
    Electronic Resource
    Electronic Resource
    Steady state osmotic adaptation inUlva lactuca (1980)
    Springer
    Planta 150 (1980), S. 158-165 
    Details
    ISSN: 1432-2048
    Keywords: β-Dimethylsulphoniopropionate ; Osmoregulation ; Ion relations ; Salinity ; Ulva
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The effects of hyper- and hypo-saline stresses on the levels of various inorganic and organic solutes inUlva lactuca have been recorded. Hypoosmotic stress decreased the tissue concentration of K+, Na+ and Cl- while hyper-osmotic stress caused a transient increase in Na+ and a stable accumulation of K+ and Cl-. The tissue content of β-dimethylsulphoniopropionate (β-dimethylpropiothetin) responded to changes in salinity. The time course of hypersaline stress showed the β-dimethylsulophoniopropionate concentration rose as the Na+ level fell. The levels of free sugars and amino acids, including proline, were relatively low in this alga and did not appear to be important in osmotic adjustment. The possibility that tertiary sulphonium dipolar ions have an analogous role in some algae to glycinebetaine and possibly other quaternary nitrogen compounds in higher plants as cytoplasmic osmotica is discussed briefly.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00582360
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  • 9
    Electronic Resource
    Electronic Resource
    Rhizosphere salinity and phytoalexin accumulation in soybean (1980)
    Springer
    Plant and soil 54 (1980), S. 163-167 
    Details
    ISSN: 1573-5036
    Keywords: Phytoalexin ; Phytophthora megasperma ; Salinity ; Soybean ; Rhizosphere
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Rhizosphere salinity decreased the capacity of soybean to accumulate a pterocarpanoid phytoalexin (glyceollin) in the stem in response toPhytophthora megasperma var.sojae. Rapid (48h) accumulation was depressed by NaCl, Na2SO4, CaCl2 and MgSO4 applications. Time-course accumulations was slowed by applications. Time-course accumulation was slowed by application of 0.131M NaCl. Glyceollin accumulation was also reduced in plants subjected to a period of high salinity stress (0.177M NaCl, 72 h) after a period of nonsalinized growth. Calcium chloride completely suppressed glyceollin accumulation in normally-resistant plants but no susceptibility to the fungus was observed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02182010
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  • 10
    Electronic Resource
    Electronic Resource
    Growth of ornamental plants irrigated with nutrient or polyethylene glycol solutions of different osmotic potentials (1980)
    Springer
    Plant and soil 56 (1980), S. 99-111 
    Details
    ISSN: 1573-5036
    Keywords: Aster ; Bedding plants ; Celosia ; Coleus ; Growth effects ; Marigold ; NPK solutions ; Osmotic stress ; Petunia ; Polyethylene glycol ; Salinity ; Snapdragon
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Six ornamental species (Petunia hybrida, Callistephus hortensis, Coleus blumei, Celosia pyramidalis, Antirrhinum majus andTagetes erecta) were grown in solutions containing high concentrations of polyethylene glycol (MW 4000) or of Nitrogen: Phosphorus: Potassium. At equal osmotic potentials, top dry weight, leaf area and leaf elongation rate were all reduced more by polyethylene glycol than by NPK. Polyethylene glycol also produced some leaf damage which did not occur with NPK solutions. Osmotic potentials of −600 kPa due to NPK reduced growth of the six species by at least 25% compared with growth of control plants (at −20 kPa). Tolerance ranking to high fertilizer in the irrigation solution increased from Snapdragon (most sensitive), Marigold Coleus, Aster, Celosia and Petunia (most tolerant).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02197957
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