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  • 1
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    German Medical Science; Düsseldorf, Köln
    In:  GMS Medizinische Informatik, Biometrie und Epidemiologie; VOL: 1; DOC02 /20050407/
    Publication Date: 2005-04-08
    Description: Before general application of a primary prevention program its efficacy has to be demonstrated. For this purpose a randomized controlled trial with active or passive follow-up may be conducted. In the last 5 years, the ratio of controlled trials with passive versus those with active follow-up was 1:13. However, under certain circumstances a passive follow-up may be more appropriate and useful to overcome the drawbacks of an active follow-up, as e.g. high costs and many drop-outs. In a randomized controlled trial, a passive follow-up is based on the reporting of cases by physicians or hospitals instead of actively following up all study participants individually. The statistical evaluation can be carried out using a one-sample chi2-test. Advantages and limitations are discussed. A passive follow-up may be advantageous in situations with low incidence, large number of participants, complete ascertainment of conditions with obligatory notification or effective disease registries and should be preferred in such a context.
    Description: Vor dem Einsatz primärer Präventionsprogramme auf Bevölkerungsebene ist deren Wirksamkeit zu prüfen. Standardmäßig werden dazu randomisierte kontrollierte Studien mit aktivem oder passivem Follow-up durchgeführt. In den letzten 5 Jahren kamen auf 1 Studie mit passivem Follow-up 13 Studien mit aktivem Follow-up. Unter bestimmten Voraussetzungen kann ein passives Follow-up jedoch geeigneter und sinnvoll sein und dazu dienen die Nachteile eines aktiven Follow-ups, wie z.B. hohe Kosten und viele Drop-outs, zu vermeiden. In einer randomisierten kontrollierten Studie mit passivem Follow-up werden alle Patienten mit der interessierenden Erkrankung von den behandelnden Ärzten oder den Krankenhäusern der Region direkt an das Studiensekretariat gemeldet. Die statistische Auswertung kann mit einem 1-Stichproben-Chi2-Test erfolgen. Die Vor- und Nachteile dieses Vorgehens werden diskutiert. Ein passives Follow-up kann in Situationen mit niedriger Inzidenz, großer Anzahl von Studienteilnehmern, Gewährleistung einer vollständigen Erhebung der Krankheitsfälle durch Betrachtung einer meldepflichtigen Erkrankung und gut geführte Krankheitsregister vorteilhaft sein und sollte dann durchaus bevorzugt werden.
    Keywords: active follow-up ; passive follow-up ; study design ; randomized controlled trial ; primary prevention program ; aktives Follow-up ; passives Follow-up ; Studiendesign ; randomiserte kontrollierte Studie ; primäres Präventionsprogramm ; ddc: 610
    Language: English
    Type: article
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  • 2
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    German Medical Science; Düsseldorf, Köln
    In:  GMS Medizinische Informatik, Biometrie und Epidemiologie; VOL: 1; DOC08 /20050620/
    Publication Date: 2005-06-21
    Description: Certainty is rare in medicine. This is a direct consequence of the individuality of each and every human being and the reason why we need medical statistics. However, statistics have their pitfalls, too. Fig. 1 shows that the suicide rate peaks in youth, while in Fig. 2 the rate is highest in midlife and Fig. 3 in old age. Which of these contradictory messages is right?After an introduction to the principles of statistical testing, this lecture examines the probability with which statistical test results are correct. For this purpose the level of significance and the power of the test are compared with the sensitivity and specificity of a diagnostic procedure. The probability of obtaining correct statistical test results is the same as that for the positive and negative correctness of a diagnostic procedure and therefore depends on prevalence.The focus then shifts to the problem of multiple statistical testing. The lecture demonstrates that for each data set of reasonable size at least one test result proves to be significant - even if the data set is produced by a random number generator. It is extremely important that a hypothesis is generated independently from the data used for its testing. These considerations enable us to understand the gradation of "lame excuses, lies and statistics" and the difference between pure truth and the full truth. Finally, two historical oracles are cited.
    Description: In der Medizin ist fast nichts sicher - dies ist eine direkte Auswirkung der Individualität jedes Menschen. Deshalb ist medizinische Statistik notwendig. Aber eine naive Interpretation von Statistiken kann in die Irre führen: Abb. 1 zeigt das Maximum der Suizidrate in der Jugend, Abb. 2 in der Mitte des Lebens, Abb. 3 im Alter. Welche dieser widersprüchlichen Botschaften ist die richtige?Nach einer Einführung in das Prinzip des statistischen Tests wird nach der Wahrscheinlichkeit gefragt, dass das Ergebnis eines statistischen Tests richtig ist. Dazu wird das Signifikanzniveau und die Power des Tests verglichen mit Sensitivität und Spezifität eines diagnostischen Verfahrens. Die Wahrscheinlichkeit für die Richtigkeit des Ergebnisses eines statistischen Tests ist wie die positive und negative Korrektheit eines diagnostischen Verfahrens und somit abhängig von der Prävalenz.Zum Problem des multiplen Testens wird gezeigt, dass an jedem Datenmaterial von vernünftiger Größe mindestens ein Test signifikant wird - auch wenn alle Daten mit dem Zufallszahlengenerator erzeugt worden sind. Es ist eminent wichtig, ob eine Hypothese unabhängig von den Daten, an denen sie getestet wird, generiert worden ist. Nach diesen Ausführungen werden Steigerungen wie "Ausreden, Lügen, Statistiken" verständlich, ebenso der Unterschied zwischen reiner Wahrheit und voller Wahrheit. Abschließend wird noch über zwei historische Orakel berichtet.
    Keywords: medical statistics ; biometry ; suicide-risk ; hypothesis testing ; diagnostic investigation ; correctness of a statistical test result ; multiple testing ; a priori formulated hypotheses ; pure versus whole truth ; historical oracles ; personal remarks ; Biometrie ; Suizidrate ; statistischer Test ; Richtigkeit eines statistischen Tests ; Richtigkeit eines diagnostischen Verfahrens ; multiples Testen ; a priori formulierte versus nachgeschobene Hypothesen ; reine versus volle Wahrheit ; persönliche Worte ; ddc: 610
    Language: German
    Type: article
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  • 3
    ISSN: 1433-0385
    Keywords: Key words: Secondary peritonitis ; Pharma economics ; Imipenem therapy ; Comparative study. ; Schlüsselwörter: Sekundäre Peritonitis ; Pharmaökonomie ; Imipenem-Therapie ; Vergleichende Studie
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung. Im Rahmen einer prospektiven, randomisierten, multizentrischen Studie wurden die Gesamtbehandlungskosten von Patienten mit sekundärer Peritonitis erhoben. Dabei wurde die Kosteneffektivität einer initialen Behandlung mit Imipenem/Cilastatin mit der anderer ausgewählter Therapieregimes verglichen. Es wurden insgesamt 154 Patienten (77 Imipenem/Cilastatingruppe, 77 Alternativtherapiegruppe), die Mannheimer Peritonitisindices zwischen 16 und 26 (Mittelwert: 20,8) aufwiesen, in die Auswertung einbezogen. Die ermittelten durchschnittlichen Gesamtkosten betrugen 11.140 DM pro Patient (Einzelwerte lagen zwischen 2.794–45.526 DM). Patienten mit einer initialen Imipenem/Cilastatintherapie verursachten im Mittel Kosten in Höhe von 10.455 DM, während für die Patienten mit einer Alternativtherapie durchschnittliche Kosten von 11.826 DM ermittelt wurden; der Unterschied zwischen den Gruppenergebnissen ist statistisch signifikant (p = 0,037).
    Notes: Summary. The total costs of the hospital treatment of patients with secondary peritonitis were investigated with a prospective, randomized, multicenter study. Moreover, the cost- effectiveness of an initial therapy with Imipenem/Cilastatin was compared to selected alternative antibiotic regimens. Altogether 154 patients (77 Imipenem/Cilastatin group, 77 alternative group) that displayed Mannheim Peritonitis Scores between 16 and 26 (average 20.8) were analyzed. The average total cost of treatment was DM 11 140 per patient (range DM 2794–45 526). Patients receiving an initial therapy with Imipenem/Cilastatin incurred average costs of DM 10 455, while patients with alternative regimens caused average costs of DM 11 826. The difference between the two treatment groups was statistically significant (P = 0.037).
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1432-0584
    Keywords: Key words De novo AML ; Adults ; HD-Ara-C/DNR consolidation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  A total of 149 consecutive de novo AML patients aged 50 years or less (median age = 37 years) were enrolled in this prospective multicenter trial initiated in May 1985. All patients received the same induction and early consolidation therapy with daunorubicin (DNR), cytosine arabinoside (Ara-C), and etoposide (DAV). High-dose Ara-C/DNR therapy included Ara-C at 3 g/m2, in 12 doses (HD-Ara-C/DNR I) and eight doses (HD-Ara-C/DNR II), followed by DNR 30 mg/m2 for 3 days. A complete remission (CR) was achieved in 104 (70%) patients; 61 complete responders received at least one cycle with HD-Ara-C/DNR. If those patients who were transplanted in first CR (n = 26), were not considered, the median relapse-free-survival (MRFS) of the remaining 78 patients was 15 months, with a probability of relapse-free survival (RFS) at 116 months of 30% (95% CI, 20–40%) after a median follow-up of 95 months. The MRFS of the HD-Ara-C/DNR consolidated patients was 25 months, with a probability of RFS at 116 months of 37% (95% CI, 24–50%). If all patients who were transplanted (n = 44) were not considered, the median survival time (MST) was 18 months with a probability of being alive at 118 months of 24% (95% CI, 16–33%). MST of the HD-Ara-C/DNR consolidated patients was 58 months with a survival probability of 46% (95% CI, 31–60%) at 118 months. Prognostic factor analysis did not reveal any significant influence of age, sex, FAB subtype, white blood cell count, hemoglobin level, thrombocyte count, LDH, or response to the first induction course on RFS of the HD-Ara-C/DNR consolidated patients. In summary, HD-Ara-C/DNR consolidation can improve the long-term outcome of a subgroup of de novo AML patients. Further improvement of the outcome seems to depend on the identification of patients with an inferior outcome under that strategy who might benefit from alternative treatment strategies.
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 1432-0584
    Keywords: De novo AML ; Adults ; HD-Ara-C/DNR consolidation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract A total of 149 consecutive de novo AML patients aged 50 years or less (median age = 37 years) were enrolled in this prospective multicenter trial initiated in May 1985. All patients received the same induction and early consolidation therapy with daunorubicin (DNR), cytosine arabinoside (Ara-C), and etoposide (DAV). High-dose Ara-C/DNR therapy included Ara-C at 3 g/m2, in 12 doses (HD-Ara-C/DNR I) and eight doses (HD-Ara-C/DNR II), followed by DNR 30 mg/m2 for 3 days. A complete remission (CR) was achieved in 104 (70%) patients; 61 complete responders received at least one cycle with HD-Ara-C/DNR. If those patients who were transplanted in first CR (n=26), were not considered, the median relapsefree-survival (MRFS) of the remaining 78 patients was 15 months, with a probability of relapse-free survival (RFS) at 116 months of 30% (95% CI, 20–40%) after a median follow-up of 95 months. The MRFS of the HD-Ara-C/DNR consolidated patients was 25 months, with a probability of RFS at 116 months of 37% (95% CI, 24–50%). If all patients who were transplanted (n=44) were not considered, the median survival time (MST) was 18 months with a probability of being alive at 118 months of 24% (95% CI, 16–33%). MST of the HD-Ara-C/DNR consolidated patients was 58 months with a survival probability of 46% (95% CI, 31–60%) at 118 months. Prognostic factor analysis did not reveal any significant influence of age, sex, FAB subtype, white blood cell count, hemoglobin level, thrombocyte count, LDH, or response to the first induction course on RFS of the HD-Ara-C/DNR consolidated patients. In summary, HD-Ara-C/DNR consolidation can improve the long-term outcome of a subgroup of de novo AML patients. Further improvement of the outcome seems to depend on the identification of patients with an inferior outcome under that strategy who might benefit from alternative treatment strategies.
    Type of Medium: Electronic Resource
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  • 6
    ISSN: 1434-4726
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
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  • 7
    ISSN: 1434-4726
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Zusammenfassung In der vorliegenden Arbeit wurde zunächst auf die Besonderheit der Klinik der Osteomyelitis der platten Schädelknochen eingegangen. Mit Rücksicht auf die Besonderheiten der Klinik der Osteomyelitis wurden die Vor- und Nachteile des radikal-operativen Vorgehens der konservativen Behandlung gegenübergestellt. Es werden Eigenbeobachtungen mitgeteilt, an Hand derer unter Berücksichtigung der Schwere des klinischen Bildes einerseits und der Notwendigkeit einer kosmetischen Rücksichtnahme andererseits der Skalpierschnitt als die Methode der Wahl vorgeschlagen wird. In der Bachbehandlung erwies sich eine Lebertransalbenbehandlung des Operationsgebietes als besonders geeignet.
    Type of Medium: Electronic Resource
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  • 8
    ISSN: 1420-9071
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Zusammenfassung Hydrolysate, hergestellt mit einerB.-subtilis-Proteaseaus Endo-und Exotoxinen pathogener Mikroorganismen, stimulieren menschliche Lymphozyten in vitro. Die Stimulation ist schwach, verglichen mit Phytohämagglutinin, und wahrscheinlich immunologisch unspezifisch.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 25 (1900), S. 236-264 
    ISSN: 0863-1778
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
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  • 10
    ISSN: 1432-1440
    Keywords: Germ cell tumors ; Gonadal toxicity ; Chemotherapy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The impact of aggressive chemotherapy on reproductive and endocrine gonadal function was prospectively studied in 44 patients with germ cell tumors. Diagnostic procedures to determine gonadal toxicity consisted of hormone determinations, semen analyses, interviews with a standardized questionnaire, and gonadal histology. After chemotherapy all patients showed elevated serum levels of follicle-stimulating hormone (FSH) and azoospermia due to germ cell and stem cell loss. Recovery of spermatogenesis, as indicated by normalization of serum FSH levels and sperm density, occurred in 77% of the patients 25–60 months after cessation of chemotherapy. In all patients serum testosterone and luteinizing hormone (LH) values remained within normal limits after therapy indicating resistance of Leydig cells to cytotoxic drugs. Three patients fathered four healthy children after completion of chemotherapy. These data suggest significant reproductive dysfunction in all men treated for germ cell tumors. However, most patients showed late and complete recovery of spermatogenesis. In contrast, endocrine gonadal function was unaffected after chemotherapy in all patients. FSH and LH are feasible markers to assess drug-induced gonadal toxicity.
    Type of Medium: Electronic Resource
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