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  • 1
    Electronic Resource
    Electronic Resource
    Epidemiologische untersuchungen zur ökologischen bleibelastung von männlichen gro\stadtbewohnern in Nordwestdeutschland (1980)
    Springer
    International archives of occupational and environmental health 46 (1980), S. 59-70 
    Details
    ISSN: 1432-1246
    Keywords: Environment ; Lead ; Free erythrocyte porphyrin ; Smoking ; Biological quality guide for lead ; Umwelt ; Blei ; freies Erythrocyten-Porphyrin ; Rauchen ; biologische Überwachung auf Gefahrdung durch Blei
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Es wurden Blutbleikonzentrationen (PbB) and FEP-Werte von 1423 bzw. 673 50jährigen Männern aus einer westdeutschen Großstadt (Köln) bestimmt. Der geometrische Mittelwert der PbB-Werte beträgt 12,8 μg/100 g, der Mittelwert der FEP-Werte 35,3 μg/100 ml Erythrocyten. Probanden, die überwiegend im Bereich der Produktion and Verarbeitung tätig waren, wiesen im Durchschnitt höhere PbB-Werte auf als die im Bereich von Büro, Verwaltung, Schule etc. Tätigen. Zigarettenraucher hatten signifikant höhere PbB-Werte als Nie-Raucher. Die höchsten mittleren PbB-Werte traten im Innenstadtbereich Bowie in drei stark industrialisierten Stadtteilen auf; in Stadtrandgebieten wurden deutlich niedrigere Werte gefunden. In dem untersuchten PbB-Bereich (3,5–56,4 μg/100 g) konnte kein statistisch signifikanter Zusammenhang zwischen erhbhten PbB- and FEP-Werten nachgewiesen werden. Die Bedeutung der PbB-Bestimmung als primarer Screening-Test zur biologischen Überwachung der Bevölkerung auf Gefahrdung durch Blei wird hervorgehoben.
    Notes: Summary Blood lead levels (PbB) and FEP-levels were measured in 1423 and 673 50-year-old males, respectively, from Cologne, a large West German city. The mean PbB value was 12.8 μg/ 100 g and the mean FEP was 35.3 μg/100 ml erythrocytes. Subjects working in production lines or in processing plants had higher PbB values than subjects working as employees and officers in administration, management, schools etc. Cigarette smokers had significant higher PbB values than non-smokers. The highest mean PbB values were found in the city centre as well as in three highly industrialized areas. PbB values were smaller in suburban areas. Within the range of PbB levels studied (3.5–56.6 μg/100 g), no statistically significant relationship between PbB and FEP could be demonstrated. The importance of PbB as a primary test for the biological screening of the population for lead is emphasized.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00377460
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  • 2
    Electronic Resource
    Electronic Resource
    Internal lead and cadmium exposure in 6-year-old children from western and eastern Germany (1994)
    Springer
    International archives of occupational and environmental health 66 (1994), S. 243-248 
    Details
    ISSN: 1432-1246
    Keywords: Lead ; Cadmium ; Blood ; Teeth ; Children
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Lead and cadmium levels in blood and deciduous teeth (shed incisors only) of 6-year-old German children were determined in 1991 in a large epidemiological study carried out in rural and urban areas of western Germany (Duisburg, Essen, Gelsenkirchen, Dortmund, Borken) and eastern Germany (Leipzig, Halle, Magdeburg, Osterburg, Gardelegen, Salzwedel). In total, blood lead and cadmium levels of 2311 German children and tooth lead and cadmium levels of 790 German children were analyzed. Blood lead levels were generally low in all study areas with geometric means between 39.3 μg/1 and 50.8 μg/l in the western German and between 42.3 μg/1 and 68.1 μg/l in the eastern German study areas. The mean blood lead level of Turkish children (n = 213) living in the western German study areas was 50.1 μg/l and thus 5.6 μg/1 higher than the overall geometric mean of the western German children. The higher exposure may be explained by a higher oral uptake from food and different living conditions. These children were excluded from multiple regression analysis because they were all living in the western study areas. The mean tooth lead levels ranged between 1.50 and 1.74 μg/g in the western and between 1.51 μg/g and 2.72 μg/g in the eastern study areas. Thus, they show a distribution pattern similar to blood. Blood and tooth lead levels were higher in urban than in rural areas and higher in the eastern German than in the western German study areas. With regard to the blood and tooth cadmium concentrations, no significant differences between the study areas could be found. The mean cadmium levels in blood ranged between 0.12 μg/1 and 0.14 μg/l and the mean tooth cadmium concentrations between 20.8 ng/g and 27.8 ng/g. Blood and tooth lead and cadmium levels of the eastern and western German children were thus mainly at a relatively low level in all rural and urban study areas. The study demonstrates and confirms that blood and tooth lead levels are influenced by several demographic, social, and environmental variables. The results indicate that there has been a further significant decrease of lead and cadmium exposure in western German children since our last epidemiological study carried out in the same study areas in 1985/1986.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00454362
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  • 3
    Electronic Resource
    Electronic Resource
    Kinetics of gametogenesis (1974)
    Springer
    Cell & tissue research 154 (1974), S. 443-470 
    Details
    ISSN: 1432-0878
    Keywords: Oocytes and T-prospermatogonia ; Rat ; Quantitative analysis ; Autoradiography
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Description / Table of Contents: Zusammenfassung Bei der Ratte findet die sexuelle Differenzierung der Gonade zwischen dem 14. und 15. Tag post conceptionem (p.c.) statt. Während dieser Zeit teilen sich die Oogonien und deren Parallelpopulation—die M-prospermatogonien (multiplying prospermatogonia) oder I-Gonocyten—sehr häufig. Um den 17. Tag p.c. tritt die letzte Generation der Oogonien bzw. der M-prospermatogonien in die Mitose. Die Mitosen bilden häufig “synchronisierte Gruppen”. Die postmitotischen Kerne ihrer Tochterzellen—der Oocyten und der T 1 prospermatogonien (primary transitional prospermatogonia) oder II-Gonocyten—sind klein. Ihr Chromatin ist in Form gröberer Schollen der Kernmembran angelagert. Auf diese Weise kommt das typische “krustenförmige” Aussehen bzw. die Ähnlichkeit mit den Prophasen der Oogonien und M-prospermatogonien zustande. Die Oocyten durchlaufen zunächst die G1-phase (etwa 10 Std Dauer) und treten dann—am Ende des Präleptotänstadiums—in die S-phase. Dann passieren sie die verschiedenen Stadien der meiotischen Prophase und treten vom 3. Tag post partum (p.p.) ab in das Dictyotänstadium. Die T1-prospermatogonien hingegen befinden sich etwa 10 Tage lang in der G1-phase, ohne wesentliche morphologische Veränderungen aufzuweisen. Vom 4. Tag p.p. an durchlaufen sie die S-Phase. Die S-Phasen-Dauer (D-S) beider Zellarten beträgt 11.5 Std und wurde durch Doppelmarkierung mit 14C- und 3H-Thymidin bestimmt. Als am besten geeignete Termine für die Bestimmung der D-S erwiesen sich bei den Oocyten der 18. Tag p.c. und bei den T1-prospermatogonien der 5. Tag p.p. Zu diesen beiden Zeitpunkten war die Anzahl der in die S-phase ein-und austretenden Oocyten bzw. T1-prospermatogonien gleich, die Zellen in S-phase befanden sich im “steady state”. Das Kernvolumen der Oogonien und M-prospermatogonien ist etwa doppelt so groß wie das der postmitotischen Oocyten und T1-prospermatogonien. Bis zum 5. Tage p.p. nimmt das Kernvolumen der Oocyten und T1-prospermatogonien um etwa das Fünffache zu. Der Degenerationsindex der Oocyten liegt wesentlich höher als der der T1-prospermatogonien; er ist postnatal besonders hoch. Aus den T1-prospermatogonien gehen am 4. und 5. Tage p.p. durch Teilung die T 2-prospermatogonien (secondary transitional prospermatogonia) hervor. Die Kerne dieses Zelltyps sind etwas kleiner also die der T1-prospermatogonien. Die T2-prospermatogonien treten am 6. Tage p.p. in die Mitose; es entstehen die ersten A-spermatogonien.
    Notes: Summary In the rat (Wistar-WU) sexual differentiation of the gonads occurs between days 14 and 15 post conception (p.c.). At this time the oogonia and their parallel population — the M-prospermatogonia (I-gonocytes)—divide rapidly. On about day 17 p.c., the last generation of oogonia and M-prospermatogonia, frequently arranged in synchronized clusters, enters mitosis. The postmitotic nuclei of their daughter cells—oocytes and T 1-prospermatogonia (II-gonocytes)—are small; coarse flakes of chromatin are associated with the nuclear membrane causing the typical “crustlike” appearance and the similarity with the prophases of oogonia and M-prospermatogonia. After the oocytes have passed a G1-phase of approximately 10 hr, they enter the S-phase at the end of the preleptotene stage. Then they pass the different stages of the meiotic prophase until they enter the dictyate stage from 3 day post partum (p.p.) onwards. The T1-prospermatogonia, on the other hand, spend a long G1-phase of about 10 days without any conspicuous morphological change before entering the S-phase from day 4 p.p. onwards. The duration of the S-pbase (D-S) of both cell types—oocytes and T1-prospermatogonia—as determined by the double labeling method with 14C- and 3H-thymidine is found to be 11.5 hr. The most favourable time for determining the D-S was day 18 p.c. for the oocytes and day 5 p.p. for the T1-prospermatogonia. On these two days the balance was reached between the cells entering and leaving the S-phase. The nuclear volumes of the postmitotic oocytes and T1-prospermatogonia are approximately half the size of those of their precursors. Until day 5 p.p. the nuclear volumes of the oocytes and T1-prospermatogonia increase about fivefold. The degeneration index of the oocytes is considerably higher than that of the T1-prospermatogonia; postnatally it is especially high. T 2 prospermatogonia arise by mitosis of the T1-prospermatogonia on day 4 and 5 p.p. The nuclei of this cell type are smaller than those of T1-prospermatogonia. T2-prospermatogonia enter mitosis on day 6 p.p and give rise to A-spermatogonia.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00219667
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