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  • Articles: DFG German National Licenses  (3)
  • 1995-1999  (1)
  • 1990-1994  (2)
  • 1960-1964
  • 24-epi-1α-hydroxyvitamin D2  (1)
  • ATPase activity  (1)
  • Acrylonitrile  (1)
Source
  • Articles: DFG German National Licenses  (3)
Material
Years
  • 1995-1999  (1)
  • 1990-1994  (2)
  • 1960-1964
Year
  • 1
    ISSN: 1432-0827
    Keywords: Bone resorption ; Osteoclast formation ; Resorption lacunae ; 24-epi-1α-hydroxyvitamin D2 ; 24-epi-1α,25-dihydroxyvitamin D2
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Abstract Bone-resorbing activities of 24-epi-1α-hydroxyvitamin D2 [24-epi-1α(OH)D2], 24-epi-1α,25-dihydroxyvitamin D2 [24-epi-1,25(OH)2D2], and 1α,24S,25-trihydroxyvitamin D2 [1,24S,25(OH)3D2], which might be a metabolite of 24-epi-1,25(OH)2D2, were investigated. In an in vitro bone resorption test, the activity of 24-epi-1α(OH)D2 was similar to that of 1α-hydroxyvitamin D3 [1α(OH)D3] at 10-9 M-10-6 M. The activity of 24-epi-1,25(OH)2D2 was weaker than that of 1α,25-dihydroxyvitamin D3 [1,25(OH)2D3] at 10-11 M-10-8 M. On the other hand, the activity of 1,24S,25(OH)3D2 was similar to that of 24-epi-1,25(OH)2D2 at 10-11 M-10-9 M. In the formation assay of osteoclast-like cells, the activity of 24-epi-1α(OH)D2 was weaker than that of 1α(OH)D3 at 10-7 M. The activity of 24-epi-1,25(OH)2D2 was almost similar to that of 1,25(OH)2D3 at 10-11 M-10-7 M. The activity of 1,24S,25(OH)3D2 was significantly weaker than that of 24-epi-1,25(OH)2D2 at 10-11 M-10-9 M. In the two experiments, the potencies of 24-epi-1,25(OH)2D2 were about 100 times higher than those of 24-epi-1α(OH)D2. In an in vivo/in vitro bone resorption test, the activity of 24-epi-1α(OH)D2 was almost similar to those of 1α(OH)D3 and 1,25(OH)2D3 and higher than those of 24-epi-1,25(OH)2D2 and 1,24S,25(OH)3D2. 24-epi-1α-(OH)D2 and 1α(OH)D3 were longer lasting than 24-epi-1,25(OH)2D2 and 1,25(OH)2D3 in this experiment. These results suggested that 24-epi-1α(OH)D2 as well as 1α(OH)D3 was converted into dihydroxy form in vivo.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1432-1246
    Keywords: Acrylonitrile ; Adducts ; Biological monitoring ; Gas chromatography ; Hemoglobin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary A new, simple and fast procedure of measuring acrylonitrile (ACN) in ACN derived mercapturic acids such as S-(2-cyanoethyl)-L-cysteine(CyEC), and in hemoglobin (Hb) and plasma protein adducts and urinary metabolites in rats and humans exposed to ACN was developed. ACN in mercapturic acids or proteins was analyzed by capillary gas chromatography (GC) by liberating ACN at a high-temperature in the injector port of GC with or without oxidizing sulfur atoms of the ACN-bound cysteines into sulfoxide form by hydrogen peroxide in vitro. At 350 °C, more than 90% of ACN in authentic CyEC was recovered by this method. Increasing a single ip dose of ACN from 5 to 50 mg/kg produced proportional increases in ACN bound to Hb 24 hr after the treatment. The alkylation of plasma protein with ACN was about 1/10 as low as that of Hb. After repeated daily ip doses of 1–10 mg/kg, ACN in Hb decreased with a half-life of about 9 days. ACN was also detected in the blood of workers exposed to ACN for 1 to 10 years at a Siberian synthetic rubber factory.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Journal of comparative physiology 160 (1990), S. 233-239 
    ISSN: 1432-136X
    Keywords: Temperature ; Acclimation ; Myosin ; Myosin heavy chain ; ATPase activity ; Carp
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Myosins were isolated from dorsal ordinary muscles of carp acclimated to 10°C and 30°C for a minimum of 5 weeks and examined for their ATPase activities. Ca2+-ATPase activity was different between myosins from cold-and warm-acclimated carp, especially at KCl concentrations ranging from 0.1 to 0.2 M, when measured at pH 7.0. The highest activity was 0.32 μmol Pi·min-1·mg-1 at 0.2 M KCl for cold-acclimated carp and 0.47 μmol Pi·min-1·mg-1 at 0.1 M KCl for warm-acclimated fish. The pH-dependency of Ca2+-ATPase activity at 0.5 M KCl for both carp was, however, similar exhibiting two maxima around 0.3 μmol Pi·min-1·mg-1 at pH 6 and 0.4 μmol Pi·min-1·mg-1 at pH 9. K+(EDTA)-ATPase activity at pH 7.0 neither exhibited differences between both myosins. It increased with increasing KCl concentration showing the highest value of about 0.4 μmol Pi·min-1·mg-1 at 0.6–0.7 M KCl. Actin-activated myosin Mg2+-ATPase activity was markedly different between cold-and warm-acclimated carp. The maximum initial velocity was 0.53 μmol Pi·min-1·mg-1 myosin at pH 7.0 and 0.05 M KCl for cold-acclimated carp, which was 1.6 times as high as that for warm-acclimated carp. These differences were in good agreement with those obtained with myofibrillar Mg2+-ATPase activity between both carp. No differences were, however, observed in myosin affinity to actin. Differences in myosin properties between cold- and warm-acclimated carp were further evidenced by its thermal stability. The inactivation rate constant of myosin Ca2+-ATPase was 25·10-4·s-1 at 30°C and pH 7.0 for cold-acclimated carp, which was about 4 times as high as that for warm-acclimated carp. Light chain composition did not differ between both carp myosins. The differences in a primary structure of the heavy chain subunit was, however, clearly demonstrated between both myosins by peptide mapping.
    Type of Medium: Electronic Resource
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