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  • 1
    Electronic Resource
    Electronic Resource
    Validation of existing and development of new prognostic classification schemes in node negative breast cancer (1997)
    Springer
    Breast cancer research and treatment 42 (1997), S. 149-163 
    Details
    ISSN: 1573-7217
    Keywords: breast cancer ; classification schemes ; measure of separation ; node negative ; recurrence-free survival ; validation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Several prognostic classification schemes in node negative breastcancer are proposed, but only the Nottingham PrognosticIndex (NPI) seems to be sufficiently validated. Validation,which is a prerequisite for a sensible assessment,is not published for two recent proposals accordingto Glick et al. [1] and Rubens [2].The German Breast Cancer Study Group (GBSG) entered662 eligible patients in a prospective observational study.603 of them had complete data for seven’standard‘ prognostic factors and median follow-up is about5 years. As there is no accepted andinformative measure of separation for classification schemes presentlyavailable, we propose a new one and useit additionally to the well known logrank-test andKaplan-Meier estimates to investigate the predictive power ofthe three schemes. Significant differences in survival andrecurrence-free survival could be established for the NPIsubgroups but not for others where even theordering of the groups was different. With theCox model and the classification and regression treeapproach we develop two new proposals for thedifferentiation of subgroups of node negative patients. Asin the NPI, tumor size and grade arethe most important factors, but with a differentweighting scheme. Young age (≤ 40 years) andvery high estrogen receptor values (〉 300 fmol)in a small subgroup of patients were associatedwith worse prognosis. The new proposals showed abetter degree of separation, which demonstrates that animprovement seems possible using standard factors. Because themeasures of separation give an overoptimistic impression forthe new proposals, a validation with other studiesis necessary before a general recommendation can begiven.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1005733404976
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  • 2
    Electronic Resource
    Electronic Resource
    The prognostic effect of histological tumor grade in node-negative breast cancer patients (1993)
    Springer
    Breast cancer research and treatment 25 (1993), S. 235-245 
    Details
    ISSN: 1573-7217
    Keywords: breast cancer ; Cox regression ; histologic tumor grading ; node negative ; prognosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The prognostic effect of histological tumor grade was evaluated in 1036 patients with early breast cancer (pT1 pN0 M0) entered into a trial comparing mastectomy and breast preserving treatment. All analyses were adjusted for the factors treatment, patients' age, and tumor size. Tumor grade was defined according to Bloom and Richardson based on the sum of scores assigned to each of three histological features: 1) degree of differentiation, 2) pleomorphism, and 3) mitotic index. The relative importance of these factors with regard to disease-free survival was evaluated. In univariate as well as in multivariate analyses the pleomorphism was the only factor showing a significant effect (univariate: p=0.0024, multivariate: p=0.015). It was investigated how the factors should be combined to define a histological grading score which yields the best possible classification of the patients with respect to prognosis. A new grading system was defined splitting the patients into three groups: 1) pleomorphism 1; 2) pleomorphism 2 or pleomorphism 3 and mitotic index 1; 3) pleomorphism 3 and mitotic index 2 or 3. This yields a good classification of the patients with respect to prognosis (p=0.0004). The prognostic effect of this score was compared with the effects of the grading systems proposed in the literature. According to Bloom and Richardson and in the modified version by Schauer and Weiss, grading is based on the sum of scores of the various histological factors. Therefore, the strong effect of the pleomorphism was diluted in these grading definitions (Bloom and Richardson: p=0.03, Schauer and Weiss: p=0.028). The grading system proposed by Le Doussalet al. consists only of the scores of pleomorphism and mitotic index (p=0.014). In summary, the factor pleomorphism showed a stronger effect on disease-free survival by itself than the grading systems proposed in the literature.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00689838
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  • 3
    Electronic Resource
    Electronic Resource
    Beiträge zur 15N-NMR-Spektroskopie Protonierung und Tautomerie in Purinen: Purin und 7- und 9-Methylpurin (1983)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 116 (1983), S. 2001-2014 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Contributions to 15N NMR Spectroscopy, Protonation and Tautomerism in Purines: Purine, 7-and 9-MethylpurineThe 15N NMR spectra of purine (1), 7- and 9-methylpurine (2, 3) have been measured and assigned in various media (NaOH, H2O, 20% H2SO4, 90% H2SO4, DMSO, CF3CO2H, FSO3H). Protonation sites and tautomer ratios are derived from the σ(15N) data. The effect of N-protonation of the geminal 15N,1H spin-spin coupling constants is discussed.
    Notes: Die 15N-NMR-Spektren von Purin (1), 7- und 9-Methylpurin (2, 3) wurden in verschiedenen Medien (NaOH, H2O, 20% H2SO4, 90% H2SO4, DMSO, CF3CO2H, FSO3H) gemessen und zugeordnet. Aus den σ(15N)-Daten werden Protonierungsorte und Tautomerie-Verhältnisse abgeleitet. Der Einfluß der N-Protonierung auf die geminalen 15N, 1H-Spin-Spin-Kopplungskonstanten wird diskutiert.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19831160526
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