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  • 1
    Electronic Resource
    Electronic Resource
    The biotransformation of tritiated 3-dehydroecdysone by crayfish,Procambarus clarkii (1993)
    Springer
    Cellular and molecular life sciences 49 (1993), S. 1101-1105 
    Details
    ISSN: 1420-9071
    Keywords: Molting hormone ; ecdysteroids ; 3-dehydroecdysone ; 3α-hydroxyecdysteroids ; Y-organ ; crayfish ; Procambarus clarkii
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract The injection of 3-dehydroecdysone (3dhE, 5 μ/g), the major ecdysteroid secreted by the Y-organ of crayfishProcambarus clarkii, resulted in apolysis within about 5 days. The hormonal response at the molecular level was investigated by injection of the radio-labeled compound; within 3 h of injection of [3H]3dhE, most radio-isotope was found in the extracted epidermal tissues and identified as ecdysone, 20-hydroxyecdysone (20E), and their 3α-hydroxy epimers. The biotransformation was undoubtedly performed in the peripheral area of the Y-organ. Cleavage of the polar conjugates, using an enzyme fromHelix pomatia, gave all of the above ecdysteroids including 3dhE. It was also found that the biosynthetic site of 3dhE was different from that of ecdysone at the subcellular level of the Y-organ.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01929922
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  • 2
    Electronic Resource
    Electronic Resource
    In vitro secretion of ecdysteroids by Y-organs of the crayfish,Procambarus clarkii (1991)
    Springer
    Cellular and molecular life sciences 47 (1991), S. 948-952 
    Details
    ISSN: 1420-9071
    Keywords: Molting hormone ; ecdysteroids ; 3-dehydroecdysone ; Y-organ ; crayfish
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract It was demonstrated that excised Y-organs of the crayfish,Procambarus clarkii, synthesize in vitro 3-dehydroecdysone (3-DHE) as the major product, together with small amounts of ecdysone. Both were identified by immunological and spectroscopic methods. The increase of ecdysteroidogenesis in the Y-organs was accompanied by an increase of the major free ecdysteroid, 20-hydroxyecdysone, in the hemolymph. This suggests a physiological role of 3-DHE, the details of which are still to be elucidated.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01929889
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    Paper (German National Licenses)
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  • 3
    Electronic Resource
    Electronic Resource
    Comparative study on determination of lead in blood by flame and flameless atomic absorption spectrophotometry with and without wet dignestion (1977)
    Springer
    International archives of occupational and environmental health 39 (1977), S. 121-126 
    Details
    ISSN: 1432-1246
    Keywords: Blood lead ; Direct Chelation-extraction ; Flame atomic absorption spectrophotometry ; Flameless atomic absorption spectrophotometry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Two series of lead-containing human blood samples, one series of 53 samples of blood impregnated with lead nitrate at various concentrations up to 100 µg/dl, and the other series of 50 samples obtained from lead-exposed workers and containing lead up to 70 µg/dl, were analyzed by the following three methods of different analytical principles; 1) the flame atomic absorption spectrophotometry after wet digestion, 2) the direct chelation-extraction (avoiding wet digestion; Hessel, 1968) followed by flame atomic absorption spectrophotometry, and 3) the flameless atomic absorption spectrophotometry. The results were compared mutually and also with those from 4) the automated analysis (Ikeda et al., 1977).It was proved that good agreements in measured values exist between any pair of the analytical methods out of the four, the correlation coefficients being higher than 0.8. The results by the second method agreed best with those by the first method (standard but time- and hand-consuming) with slope of the regression line next to 1 and a very small intercept. The advantages of the methods studied were compared.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00380892
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    Paper (German National Licenses)
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  • 4
    Electronic Resource
    Electronic Resource
    Urinary lead as a possible surrogate of blood lead among workers occupationally exposed to lead (1999)
    Springer
    International archives of occupational and environmental health 72 (1999), S. 516-520 
    Details
    ISSN: 1432-1246
    Keywords: Key words Biological monitoring ; Blood lead ; Urinary lead
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Objectives: The aim of the present study is to investigate whether lead (Pb) in urine (Pb-U) can be a valid surrogate of lead in blood (Pb-B), the traditional biomarker of exposure to lead in occupational health. Methods: Blood and spot urine samples were collected from 258 workers of both sexes occupationally exposed to lead. The samples were analyzed for lead by graphite furnace atomic absorption spectrometry, and the correlation between Pb-B and Pb-U was examined by linear regression analysis before and after logarithmic conversion. Results: The correlation coefficient (0.824; P 〈 0.01) was largest when the relationship between Pb-B and Pb-U was examined with 214 cases of one sex (i.e., men) after Pb-U was corrected for a specific gravity (1.016) of urine (Pb-Usg) and both Pb-B and Pb-Usg were converted to logarithms. The geometric means (GMs) of Pb-B and Pb-Usg for the 214 men were 489 μg/l and 81 μg/l, respectively. When Pb-Usg was assumed to be 100 μg/l in this set of correlations, the 95% confidence range of Pb-B for the group mean was narrow, i.e., 543–575 μg/l (with GM of 559 μg/l), whereas that for individual Pb-B values was as wide as 355–881 μg/l. Conclusions: The correlation of Pb-U with Pb-B among workers occupationally exposed to Pb was close enough to suggest that Pb-U may be a good alternative to Pb-B on a group basis, but not close enough to allow Pb-U to predict Pb-B on an individual basis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004200050409
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    Paper (German National Licenses)
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