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  • Elektroden, ionenselektive  (3)
  • Cell cycle  (2)
  • 1
    Electronic Resource
    Electronic Resource
    Immunostaining for proliferating cell nuclear antigen: its role in determination of proliferation in routinely processed human brain tumor specimens (1993)
    Springer
    Acta neuropathologica 86 (1993), S. 582-589 
    Details
    ISSN: 1432-0533
    Keywords: Cell kinetics ; Cell cycle ; Brain tumor ; Cell proliferation ; Proliferating cell nuclear antigen
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Alcohol- and formalin-fixed, paraffin-embedded samples of 71 brain tumors (35 gliomas, 22 metastatic carcinomas, 8 meningiomas and 6 other tumors) were investigated by immunocytochemistry with three different monoclonal antibodies against proliferating cell nuclear antigen (PCNA)/cyclin (19A2; 19F4; PC10). PC10 was found to work best; it is applicable to both alcohol- and formalin-fixed tumor samples. PCNA labeling indices (LIs) were compared in the same tumors with LIs obtained by Ki-67 immunostaining of frozen sections and by in vitro incubation with bromodeoxyuridine (BrdUrd); in the latter preparations, BrdUrd LIs could be compared with PCNA LIs in the very same areas of serial sections. In gliomas, PCNA LIs were 0.7–80.2% (mean 31.7%), in metastases 0–76.0% (mean 47.8%), and in meningiomas 0–53.0% (mean 19.3%). In general, PCNA LIs were highly significantly correlated with Ki-67 LIs (P=0.0002) and BrdUrd LIs (P=0.0001). However, when tumor subgroups are considered, only gliomas show a significant correlation with Ki-67 and BrdUrd LIs. Despite this statistical correlation, PCNA expression was out of proportion to proliferation indices as determined by both other methods in almost one third of all brain tumors. Immunocytochemistry for PCNA produces a broad spectrum of staining intensity of labeled nuclei, whose number is dependent upon the sensitivity of the immunocytochemical technique used. Thus, inter-oberserver and inter-laboratory variabilities in PCNA LI determination may occur. Overlapping of PCNA LIs between tumor subgroups of varying malignancy further limits the informational value for the individual case. In some classic meningiomas, high PCNA scores do not reflect the proliferative activity of the tumor, as Ki-67 and BrdUrd LIs are very low in these cases. We conclude that PCNA immunolabeling is of limited value in the individual tumor, mainly due to overexpression in many tumors, and at present cannot be recommended to replace Ki-67 and/or BrdUrd labeling methods for routine determination of proliferative activity in human tumor specimens.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00294296
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    Argyrophilic nucleolar organizer region proteins (Ag-NORs) in human brain tumors: relations with grade of malignany and proliferation indices (1990)
    Springer
    Acta neuropathologica 80 (1990), S. 156-162 
    Details
    ISSN: 1432-0533
    Keywords: Cell kinetics ; Cell cycle ; Brain tumor ; Cell proliferation ; Nucleolar organizer region proteins
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Proliferation indices and mean number of silver-stained nucleolar organizer region-associated proteins (Ag-NORs) are compared in 65 brain tumors, including 34 gliomas, 8 meningiomas, 17 metastatic tumors, and 6 other tumors. Immunocytochemical investigations include labeling with the monoclonal antibody Ki-67 which identifies the whole growth fraction, and with a monoclonal antibody against bromodeoxyuridine (BrdUrd) which detects cells in the S phase of the cell cycle after in vitro incubation with BrdUrd. When all types of tumors are collectively considered, mean numbers of Ag-NORs did not correlate with Ki-67 and Brd-Urd labeling indices (LIs) and mitotic index. Among tumor subtypes, only meningiomas showed significant correlations between Ag-NOR counts, LIs, and malignancy. Mean number of Ag-NORs did not correlate with proliferation indices and tumor grade in low-grade and high-grade gliomas. However, recurrent high-grade gliomas showed a tendency to higher Ag-NOR counts than primary tumors. This study indicates that counting of Ag-NORs in paraffin sections is of limited value in tumor neuropathology. Correlations found in meningeal tumors should be substantiated in larger series.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00308919
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    Paper (German National Licenses)
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  • 3
    Electronic Resource
    Electronic Resource
    Ionenselektive Coated Glass-Elektroden (1979)
    Springer
    Fresenius' Zeitschrift für analytische Chemie 299 (1979), S. 115-118 
    Details
    ISSN: 1618-2650
    Keywords: Elektroden, ionenselektive ; coated glass, Carrier-PVC-Membran, Na, K, NH4, Ca
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung Na+-, K+-, NH 4 + - und Ca2+ selektive coated glass-Elektroden wurden entwickelt, bei denen eine ionenselektive Carrier-PVC-Membran auf eine ionenselektive Glasschicht aufgebracht wird, die über einen Innenelektrolyten mit der Ableitelektrode in Verbindung steht. Die Selektivität wird durch die aufgebrachte Carrier-PVC-Membran bestimmt, die zusätzlich Weichmacher zur Optimierung der Eigenschaften enthält.
    Notes: Summary Na+, K+, NH 4 + and Ca2+ selective electrodes have been developed by coating the ion-selective glass layer with a carrier PVC membrane. The glass is in contact with the conducting electrode through an inner electrolyte. The selectivity is determined by the PVC membrane, containing neutral carriers or electrically charged ligands and additionally plasticizers for optimizing the properties.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00518421
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  • 4
    Electronic Resource
    Electronic Resource
    Zur Reproduzierbarkeit von Na+-, K+- und Ca2+-selektiven Diskelektroden in Abhängigkeit vom Anzeigefehler des verwendeten Potentialmeßgerätes (1980)
    Springer
    Fresenius' Zeitschrift für analytische Chemie 301 (1980), S. 406-409 
    Details
    ISSN: 1618-2650
    Keywords: Elektroden, ionenselektive ; Reproduzierbarkeit, Zweipunkteichung, Diskelektroden
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung Für die Na+-, K+- und Ca2+ -Bestimmung mit ionenselektiven Diskelektroden im medizinischen Bereich empfiehlt sich die Zweipunkteichung. Die mit diesem Verfahren erzielbare Reproduzierbarkeit wird theoretisch aufgrund des Ablesefehlers am Meßinstrument berechnet und mit experimentellen Werten verglichen. Die theoretisch berechneten und experimentellen Standardabweichungen liegen für 1-wertige Ionen bei 0,3 % und für 2-wertige bei 0,6 %. Die Genauigkeit wird nicht durch die Elektroden, sondern die gegenwärtig verfügbaren Meßgeräte begrenzt.
    Notes: Summary In clinical analysis it is recommendable to use a two-point calibration for the determination of Na+, K+ and Ca2+ ions by ion-selective disc electrodes. The accuracy, which can be obtained by this calibration method, is treated theoretically, and the results are compared with experimental data. Theoretical and experimental standard deviations are in very good agreement, with 0.3 % for Na+ and K+ and 0.6 % for Ca2+. The precision is limited by the measuring instrument and not by the disc electrodes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00475747
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    Paper (German National Licenses)
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  • 5
    Electronic Resource
    Electronic Resource
    Strömungsoptimiertes Multimeßsystem mit ionenselektiven Diskelektroden (1980)
    Springer
    Fresenius' Zeitschrift für analytische Chemie 301 (1980), S. 410-413 
    Details
    ISSN: 1618-2650
    Keywords: Elektroden, ionenselektive ; Diskelektroden, strömungsoptimiertes Multimeßsystem
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung Es wird ein strömungsoptimiertes Multimeßsystem mit ionenselektiven Diskelektroden vorgestellt, bei dem aufgrund stromlinienförmiger Erhebungen im Kanalsystem gegenüber den Carrier-PVC-Membranen in Verbindung mit einem stau- und totzonenarmen Strömungsverlauf eine trägheitsarme und präzise ionenselektive Analytik gewährleistet wird. In das Meßsystem lassen sich auch andere Sensoren wie pH-, gassensitive und Enzym-Elektroden einführen.
    Notes: Summary The proposed system ensures low-inertia and precise measurements by means of ion-selective disc electrodes. This is achieved by streamlined elevations in the channel system opposite to the carrier PVC membranes, caring for a flow low in stagnation and dead zones. Other sensors may also be used in this system, as e.g. pH-, gas-sensitive and enzyme electrodes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00475748
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    Paper (German National Licenses)
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