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Einkauf im virtuellen Markt
(2000)
Summary
Background: Combination chemotherapies of platinum compounds with alkylating agents have been the standard treatment for patients with advanced ovarian carcinoma over the last decades. The recent development of taxans has added a group of new promising agents; however, long-term results are not yet available. Platin derivates have proven to be an indispensable part in combination chemotherapies for ovarian carcinoma. The dose intensity of cisplatin is, however, still a matter of debate. We report on the long-term results of a prospective randomized trial comparing two dosages of cisplatin combined with treosulfan in patients with advanced epithelial ovarian cancer. Patients and Methods: Between 1988 and 1995, 125 patients with ovarian cancer (FIGO stage II–IV) were randomized to receive 4 cycles (28-day intervals) of either cisplatin 100 mg/m2 (high dose, HD) or 50 mg/m2 (low dose, LD) in combination with 5 g/m2 treosulfan after primary cytoreductive surgery. Postoperative residual tumor was absent in 39 patients (HD: 16; LD: 23), < 2 cm in 61 patients (HD: 36; LD: 25) and > 2 cm in 25 patients (HD: 13; LD: 12). 65 and 60 patients received HD and LD cisplatin, respectively. Second-look surgery was optional. Results:The overall response rate was 70.0% (HD: 70.9%; LD: 68.9%). Pathological complete response (CR) was seen in 45 patients (37.5%), clinical CR in 23 patients (19.2%), partial response (PR) in 16 patients (13.3%), stable disease (SD) in 2 patients, and progression of disease (PD) in 34 patients (28.3%). 5 patients were not assessable for response. Overall median survival was 25.6 (HD: 26.9, LD: 25.2) months. The overall disease-free survival for responders was 19.6 and 24.7 months (HD and LD, respectively). HD chemotherapy did not result in any significant survival benefit in completely resected patients: HD: 39.8 months versus LD: 49.5 months. In suboptimally debulked patients (residual tumor < 2 cm), median survival was 24.1 months (HD) versus 22.6 months (LD). In patients with residual tumors > 2 cm median survival was 14.6 months (HD) versus 15.5 months (LD). Significantly less side effects were seen in the LD group: anemia (p = 0.008); nephrotoxicity (p = 0.014); alopecia (p = 0.017). Conclusions: Our data suggest that LD cisplatin-based chemotherapy is as effective as HD chemotherapy in patients with advanced epithelial ovarian cancer, but is far less toxic.
Copyright © 2000 S. Karger GmbH, Freiburg
BACKGROUND
Despite radical surgery and the introduction of novel chemotherapeutic agents, the prognosis of ovarian cancer remains poor. Since in the past the potential role of gonadotropins in the induction and progression of ovarian cancer has been discussed, we conjugated doxorubicin to human chorionic gonadotropin (hCG) in order to specifically target ovarian cancer cells.
MATERIALS AND METHODS
Doxorubicin was conjugated to hCG via glutaraldehyde. 48 hours post seeding, NIH:OVCAR 3 cells were treated with various concentrations of hCG-conjugated and non-conjugated doxorubicin for 2 hours. Cells were cultured for a total of 168 hours. Cell growth was monitored by a crystal violet assay.
RESULTS
Conjugating doxorubicin to hCG resulted in an average specific uptake of 22 mol doxorubicin per mol protein (range 3.0-43.3 mol). Incubating NIH:OVCAR 3 cells for 2 hours with the conjugate led to a more than 8 fold increase of the IC50 values compared to non-conjugated doxorubicin (0.55 microM versus 4.43 microM). The antiproliferative activity of both conjugated and free doxorubicin was detectable up to 168 hours post treatment.
CONCLUSIONS
The present experiments clearly demonstrate a more than 8-fold increase in cytotoxicity of the conjugates compared to free doxorubicin. It was also shown that this effect was not restricted to an acute toxic event but that it resulted in a prolonged antiproliferative activity.
Wahlverhalten von Schülern der Sekundarstufe II im Fach Physik seit 1990 im bundesweiten Vergleich
(2000)
Max Planck legte 1900 mit dem nach ihm benannten Strahlungsgesetz das quantitative Fundament zu so genannten Wärmebildsystemen. 100 Jahre später gibt es — mit bedingt durch Fortschritte in der Halbleitertechnologie und Mikrosystemtechnik — Infrarotkameras, mit denen sowohl die von Planck untersuchten Strahlungsgesetze zur Hohlraumstrahlung als auch allgemein wissenschaftliche und technische Anwendungen der Temperaturstrahlung von Körpern untersucht werden können. Darüber hinaus bieten sich solche Systeme auch für didaktische Zwecke an, da physikalische Gesetzmäßigkeiten mit Energieaustauschprozesssen aus sehr vielen Gebieten der Physik durch eine etwas andere, physikalische Sehweise visualisiert und damit für Lehrzwecke eingesetzt werden können.
Das ist ein seltsam wunderbares Zeichen! Ein Streifzug durch die Kulturgeschichte des Regenbogens
(2000)
Bei dem zu beobachtenden Altern der Bevölkerung stellt sich die Frage nach der künftigen Wettbewerbsfähigkeit des Industriestandorts Deutschland, der mit gealterten Belegschaften am Weltmarkt bestehen muss. Besonders akzentuiert könnte die Problemlage bei innovationsintensiven Tätigkeitsfeldern sein, in denen die hohen Anforderungen an aktuelles Wissen, Belastbarkeit und Kreativität nach dem „Defizit-Modell“ des Alterns eher mit Jugend assoziiert werden. Folglich müssten Unternehmen besonders in innovationsnahen Tätigkeiten der Industrie eine rapide Verjüngung anstreben. Eine Untersuchung der westdeutschen Industrie zwischen 1990 und 1996 zeigt jedoch, dass es bei „Innovatoren“ (Ingenieure, Techniker) keinen überdurchschnittlichen altersselektiven Personalabbau gegeben hat. Vielmehr ist die allgemeine „Verjüngung“ der Industriebelegschaften auf den deutlichen Personalabbau in der Großindustrie, der im Wesentlichen über Altersabgänge geregelt wurde, zurückzuführen. In der Entwicklung der industriellen Personalstruktur findet sich also kein Beleg für die These vom Alter als spezifisches Innovationsproblem.
Experimentelle Validierung einer optimalen Anfahrstrategie für hochrein trennende Bodenkolonnen
(2000)
Flexible startup, shutdown and product changeover procedures are necessary in today's chemical industry. The startup of chemical processes, such as distillation, represents one of the most complicated procedures in industrial practice. The computational and experimental results show that the optimal control policies can improve the operation performance with time saving of up to 45 %. This allows a significant reduction of energy and raw material consumption also and consequently can lead to a more economical process.
Dynamic optimization of processes in chemical industry became important in the last decade. Simulated annealing belongs to these optimization procedures, which allow to reach the global optimum, but are very time-consuming. In this paper, the simulated annealing algorithm has been formulated in a way to enable direct call of process simulators coded in the commercial simulation tool SPEEDUP. We apply simulated annealing for the determination of operation policies in a binary distillation. The developed approach allows the prediction of reflux flow rate and reboiler duty in order to minimize the operation time for product switchover of the column.
Copyright © 2000 Elsevier Science S.A.
PURPOSE: To evaluate the detection of epithelial cells in bone marrow of breast cancer patients as an indicator of metastatic disease.
PATIENTS AND METHODS: Between 1989 and 1994, bone marrow biopsies were performed on 393 breast cancer patients during primary surgery. Specimens were stained immunocytochemically for epithelial cells expressing cytokeratins or the epithelial membrane antigen. The long-term outcomes of these patients were analyzed in this study.
RESULTS: In 166 of 393 patients, epithelial cells were found in bone marrow (BM) aspirates. These patients were designated BM+. The rate of tumor recurrence or cancer-related death was significantly higher in BM+ patients than in BM− patients. Multivariate analysis using the Cox regression model revealed BM status as a prognostic parameter independent of tumor size and axillary lymph node status. However, tumor size and axillary lymph node status were clearly superior prognostic parameters.
CONCLUSION: Disseminated epithelial cells in BM are associated with poor clinical outcome in breast cancer patients. However, the presence of these cells is not a sufficient parameter to predict growing metastases in the majority of patients, suggesting that epithelial cells in the BM of breast cancer patients at the time of surgery have limited metastatic potential. The role of these cells needs to be further evaluated.
The IGF-1 receptor (IGF-1-R) belongs to the tyrosine kinase growth factor receptor family. It is structurally similar to, but distinct from, the insulin receptor, with which it shares a 70% homology. As expected, it crossreacts with insulin and, vice versa, insulin receptor crossreacts with IGF-1. Numerous studies suggest that IGF-1-R is very important for mitogenesis and is essential for phenotype transformation, at least in rodents (1). In particular, the IGF-1-R has been described in human breast cancer (2-4) and ovarian cancer (5) tissues and in cultured human breast cancer cell lines (6,7).
Coole Experimente
(2001)
Experimente mit flüssigem Stickstoff kommen in der Lehre - vor allem an Hochschulen - bislang zu kurz. Dabei gibt es schöne Versuche aus nahezu allen Bereichen der Physik, die in Lehrveranstaltungen relativ einfach vorgeführt werden können. Wir stellen hier einige Experimente vor, die eindrucksvoll demonstrieren,wie sich physikalische Eigenschaften bei tiefen Temperaturen ändern.
Strahlungsgesetz und Augenempfindlichkeit: Bemerkungen zu einer klassischen Fehlinterpretation
(2001)
Universality of correlationships among pulse parameters for different MIG Welding Power Sources
(2001)
Dieser Beitrag der Hochschule Anhalt (FH) und der gedas beschreibt ein Modellsystem mit dem Ziel, das Verhalten von Reifen auf unterschiedlichen Straßenbelägen zu berechnen. Neben der Modellierung des Reifens selbst liegt ein weiterer Schwerpunkt auf der Darstellung realer Straßenverhältnisse basierend auf Messungen unter Verwendung eines Millimetergitters. Simulationen im Bereich der Fahrdynamik, des Fahrkomforts bis hin zu Lebensdauertests mit virtuellen Fahrzeugmodellen können mit dem Modellsystem RMOD-K bereits in einem frühen Stadium der Fahrzeugentwicklung durchgeführt werden.
For most separations fully thermally coupled distillation columns are thermodynamically more efficient than conventional arrangements. In spite of the superiority of double-effect distillation systems to a single column concerning energy savings these systems are not often used in the industrial practice, because of the disadvantages in dynamic operability. Generally the product switchover is a complicated and protracted operation, where many process variables must be changed simultaneously. The economic and ecological interest is to minimize the time of switchover periods, which are generally non-productive and require long times especially for coupled systems. The aim of this study is to reduce the time needed for the product switchover of coupled distillation systems. This paper presents a new product switchover strategy, which will lead to a time saving of 57%. Furthermore, a new startup strategy is developed and verified in experimental studies. The results demonstrate that using the optimized startup strategy a time saving of 57% can be achieved too and thereby these unproductive periods can be reduced significantly.
Copyright © 2001 Elsevier Science B.V.