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  • 1
    facet.materialart.
    Unbekannt
    Publikationsdatum: 2014-02-26
    Beschreibung: Zeitschriften und andere Medien werden in wachsendem Maße elektronisch publiziert. Hier entsteht für die Bibliotheken, welche diese Online-Publikationen ihren Lesern zur Verfügung stellen, ein neuer Bereich der Informationsvermittlung. Mit dem aufkommenden Standard der OpenURL ergeben sich neue Möglichkeiten, dem Benutzer weiterführende Links und Dienste anzubieten. Das Document-Linking-System SFX der Firma Ex Libris ist die erste und bekannteste Anwendung, die ein Managementsystem fr die Auswertung der OpenURL implementiert. Im Rahmen eines Projektes hat die Zentrale des Kooperativen Bibliotheksverbundes Berlin-Brandenburg (KOBV) eine Evaluation von SFX durchgeführt. Als Ergebnis der Evaluation sollten Einsatzmöglichkeiten von SFX für die KOBV-Suchmaschine und in den lokalen Bibliothekssystemen und Informationsportalen aufgezeigt werden. Im Verlauf des Projektes hat sich das Produkt SFX als eine stabile Anwendung erwiesen, die dem Benutzer interessante zusätzliche Dienste bieten kann.
    Schlagwort(e): ddc:000
    Sprache: Deutsch
    Materialart: reportzib , doc-type:preprint
    Format: application/postscript
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  • 2
    Publikationsdatum: 2014-02-26
    Beschreibung: In this work we present an approach for the sensitivity analysis of linearly-implicit differential-algebraic equation systems. Solutions for both, states and sensitivities are obtained by applying an extrapolated linearly implicit Euler discretization scheme. This approach is compared to the widely used sensitivity extensions of multi-step BDF methods by means of case studies. Especially, we point out the benefit of this method in the context of dynamic optimization using the sequential approach.
    Schlagwort(e): ddc:000
    Sprache: Englisch
    Materialart: reportzib , doc-type:preprint
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  • 3
    Publikationsdatum: 2014-09-30
    Beschreibung: Decomposition of the high dimensional conformational space of bio-molecules into metastable subsets is used for data reduction of long molecular trajectories in order to facilitate chemical analysis and to improve convergence of simulations within these subsets. The metastability is identified by the Perron-cluster cluster analysis of a Markov process that generates the thermodynamic distribution. A necessary prerequisite of this analysis is the discretization of the conformational space. A combinatorial approach via discretization of each degree of freedom will end in the so called ''curse of dimension''. In the following paper we analyze Hybrid Monte Carlo simulations of small, drug-like biomolecules and focus on the dihedral degrees of freedom as indicators of conformational changes. To avoid the ''curse of dimension'', the projection of the underlying Markov operator on each dihedral is analyzed according to its metastability. In each decomposition step of a recursive procedure, those significant dihedrals, which indicate high metastability, are used for further decomposition. The procedure is introduced as part of a hierarchical protocol of simulations at different temperatures. The convergence of simulations within metastable subsets is used as an ''a posteriori'' criterion for a successful identification of metastability. All results are presented with the visualization program AmiraMol.
    Schlagwort(e): ddc:000
    Sprache: Englisch
    Materialart: reportzib , doc-type:preprint
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  • 4
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    Unbekannt
    Publikationsdatum: 2019-05-10
    Beschreibung: The adaptive finite element code {\sc Kardos} solves nonlinear parabolic systems of partial differential equations. It is applied to a wide range of problems from physics, chemistry, and engineering in one, two, or three space dimensions. The implementation is based on the programming language C. Adaptive finite element techniques are employed to provide solvers of optimal complexity. This implies a posteriori error estimation, local mesh refinement, and preconditioning of linear systems. Linearely implicit time integrators of {\em Rosenbrock} type allow for controlling the time steps adaptively and for solving nonlinear problems without using {\em Newton's} iterations. The program has proved to be robust and reliable. The user's guide explains all details a user of {\sc Kardos} has to consider: the description of the partial differential equations with their boundary and initial conditions, the triangulation of the domain, and the setting of parameters controlling the numerical algorithm. A couple of examples makes familiar to problems which were treated with {\sc Kardos}. We are extending this guide continuously. The latest version is available by network: {\begin{rawhtml} 〈A href="http://www.zib.de/Numerik/software/kardos/"〉 〈i〉 Downloads.〈/i〉〈/a〉 \end{rawhtml}}
    Schlagwort(e): ddc:000
    Sprache: Englisch
    Materialart: reportzib , doc-type:preprint
    Format: application/postscript
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  • 5
    Publikationsdatum: 2016-06-09
    Beschreibung: This article studies the relation of the two scientific languages Chemistry and Mathematics via three selected comparisons: (a) QSSA versus dynamic ILDM in reaction kinetics, (b) lumping versus discrete Galerkin methods in polymer chemistry, and (c) geometrical conformations versus metastable conformations in drug design. The common clear message from these comparisons is that chemical intuition may pave the way for mathematical concepts just as chemical concepts may gain from mathematical precisioning. Along this line, significant improvements in chemical research and engineering have already been possible -- and can be further expected in the future from the dialogue between the two scientific languages.
    Schlagwort(e): ddc:000
    Sprache: Englisch
    Materialart: reportzib , doc-type:preprint
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  • 6
    Publikationsdatum: 2014-11-10
    Beschreibung: Several sets of reductions rules are known for preprocessing a graph when computing its treewidth. In this paper, we give reduction rules for a weighted variant of treewidth, motivated by the analysis of algorithms for probabilistic networks. We present two general reduction rules that are safe for weighted treewidth. They generalise many of the existing reduction rules for treewidth. Experimental results show that these reduction rules can significantly reduce the problem size for several instances of real-life probabilistic networks.
    Schlagwort(e): ddc:000
    Sprache: Englisch
    Materialart: reportzib , doc-type:preprint
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  • 7
    Publikationsdatum: 2014-02-26
    Beschreibung: Signaling is crucial to the operation of modern telecommunication networks. A breakdown in the signaling infrastructure typically causes customer service failures, incurs revenue losses, and hampers the company image. Therefore, the signaling network has to be highest reliability and survivability. This in particular holds for the routers in such a network, called \textit{signaling transfer points\/} (STPs). The robustness of an STP can be improved by equally distributing the load over the internal processing units. Several constraints have to be taken into account. The load of the links connected to a processing unit changes over time introducing an imbalance of the load. In this paper, we show how integer linear programming can be applied to reduce the imbalance within an STP, while keeping the number of changes small. Two alternative models are presented. Computational experiments validate the integer programming approach in practice. The GSM network operator E-Plus saves substantial amounts of time and money by employing the proposed approach.
    Schlagwort(e): ddc:000
    Sprache: Englisch
    Materialart: reportzib , doc-type:preprint
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  • 8
    facet.materialart.
    Unbekannt
    Publikationsdatum: 2019-10-24
    Schlagwort(e): ddc:000
    Sprache: Deutsch
    Materialart: annualzib , doc-type:report
    Format: application/pdf
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  • 9
    Publikationsdatum: 2020-11-13
    Beschreibung: In the problem of \emph{Online Call Admission in Optical Networks}, briefly called \textsc{oca}, we are given a graph $G=(V,E)$ together with a set of wavelengths~$W$ and a finite sequence $\sigma=r_1,r_2,\dots$ of calls which arrive in an online fashion. Each call~$r_j$ specifies a pair of nodes to be connected and an integral demand indicating the number of required lightpaths. A lightpath is a path in~$G$ together with a wavelength~$\lambda \in W$. Upon arrival of a call, an online algorithm must decide immediately and irrevocably whether to accept or to reject the call without any knowledge of calls which appear later in the sequence. If the call is accepted, the algorithm must provide the requested number of lightpaths to connect the specified nodes. The essential restriction is the wavelength conflict constraint: each wavelength is available only once per edge, which implies that two lightpaths sharing an edge must have different wavelengths. Each accepted call contributes a benefit equal to its demand to the overall profit. The objective in \textsc{oca} is to maximize the overall profit. Competitive algorithms for \textsc{oca} have been known for the special case where every call requests just a single lightpath. In this paper we present the first competitive online algorithms for the general case of larger demands.
    Schlagwort(e): ddc:000
    Sprache: Englisch
    Materialart: reportzib , doc-type:preprint
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  • 10
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    Unbekannt
    Publikationsdatum: 2020-11-13
    Beschreibung: Traditional optimization techniques assume, in general, knowledge of all data of a problem instance. There are many cases in practice, however, where decisions have to be made before complete information about the data is available. In fact, it may be necessary to produce a part of the problem solution as soon as a new piece of information becomes known. This is called an \emph{online situation}, and an algorithm is termed \emph{online}, if it makes a decision (computes a partial solution) whenever a new piece of data requests an action. \emph{Competitive analysis} has become a standard yardstick to measure the quality of online algorithms. One compares the solution produced by an online algorithm to that of an optimal (clairvoyant) offline algorithm. An online algorithm is called $c$-competitive if on every input the solution it produces has cost'' at most $c$~times that of the optimal offline algorithm. This situation can be imagined as a game between an online player and a malicious adversary. Although competitive analysis is a worst-case analysis and henceforth pessimistic, it often allows important insights into the problem structure. One can obtain an idea about what kind of strategies are promising for real-world systems and why. On the other hand there are also cases where the offline adversary is simply too powerful and allows only trivial competitiveness results. This phenomenon is called hitting the triviality barrier''. We investigate several online problems by means of competitive analysis. We also introduce new concepts to overcome the weaknesses of the standard approach and to go beyond the triviality barrier.
    Schlagwort(e): ddc:000
    Sprache: Englisch
    Materialart: doctoralthesis , doc-type:doctoralThesis
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  • 11
    Publikationsdatum: 2014-02-26
    Beschreibung: The paper deals with the two-class priority M/M/1 system, where the prioritized class-1 customers are served under FCFS preemptive resume discipline and may become impatient during their waiting for service with generally distributed maximal waiting times but finite expectation. The class-2 customers have no impatience. The required mean service times may depend on the class of the customer. As the dynamics of class-1 customers are related to the well analyzed M/M/1+GI system, our aim is to derive characteristics for class-2 customers and for the whole system. The solution of the balance equations for the partial probability generating functions of the detailed system state process is given in terms of the weak solution of a family of boundary value problems for ordinary differential equations. By means of this solution formulae for the joint occupancy distribution and for the sojourn and waiting times of class-2 customers are derived generalizing results recently obtained by Choi et al. in case of deterministic maximal waiting times. For deterministic maximal waiting times partially new explicit formulae are given.
    Schlagwort(e): ddc:000
    Sprache: Englisch
    Materialart: reportzib , doc-type:preprint
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  • 12
    Publikationsdatum: 2016-06-09
    Beschreibung: The bio-heat transfer equation is a macroscopic model for describing the heat transfer in microvascular tissue. So far the deduction of the Helmholtz term in the bio-heat transfer equation is not co role. In view of a future numerical application of this new mathematical model to treatment planning in hyperthermia we derive asymptotic estimates for first and second order correctors.
    Schlagwort(e): ddc:000
    Sprache: Englisch
    Materialart: reportzib , doc-type:preprint
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  • 13
    Publikationsdatum: 2021-08-05
    Beschreibung: Mixed integer programs ($MIPs$) are commonly solved with branch and bound algorithms based on linear programming. The success and the speed of the algorithm strongly depends on the strategy used to select the branching variables. Today's state-of-the-art strategy is called \emph{pseudocost branching} and uses information of previous branchings to determine the current branching. We propose a modification of \emph{pseudocost branching} which we call \emph{history branching}. This strategy has been implemented in $SIP$, a state-of-the-art $MIP$ solver. We give computational results that show the superiority of the new strategy.
    Schlagwort(e): ddc:000
    Sprache: Englisch
    Materialart: reportzib , doc-type:preprint
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  • 14
    Publikationsdatum: 2020-11-13
    Beschreibung: We consider the design of transparent optical networks from a practical perspective. Network operators aim at satisfying the communication demands at minimum cost. Such an optimization involves three interdependent planning issues: the dimensioning of the physical topology, the routing of lightpaths, and the wavelength assignment. Further topics include the reliability of the configuration and sparse wavelength conversion for efficient use of the capacities. In this paper, we investigate this extensive optical network design task. Using a flexible device-based model, we present an integer programming formulation that supports greenfield planning as well as expansion planning on top of an existing network. As solution method, we propose a suitable decomposition approach that separates the wavelength assignment from the dimensioning and routing. Our method in particular provides a lower bound on the total cost which allows to rate the solution quality. Computational experiments on realistic networks approve the solution approach to be appropriate.
    Schlagwort(e): ddc:000
    Sprache: Englisch
    Materialart: reportzib , doc-type:preprint
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  • 15
    Publikationsdatum: 2020-11-13
    Beschreibung: Today's telecommunication networks are configured statically. Whenever a connection is established, the customer has permanent access to it. However, it is observed that usually the connection is not used continuously. At this point, dynamic provisioning could increase the utilization of network resources. WDM based Optical Transport Networks (OTNs) will shortly allow for fast dynamic network reconfiguration. This enables optical broadband leased line services on demand. Since service requests competing for network resources may lead to service blocking, it is vital to use appropriate strategies for routing and wavelength assignment in transparent optical networks. We simulate the service blocking probabilities of various dynamic algorithms for this problem using a well-founded traffic model for two realistic networks. One of the algorithms using shortest path routings performs best on all instances. Surprisingly, the tie-breaking rule between equally short paths in different wavelengths decides between success or failure.
    Schlagwort(e): ddc:000
    Sprache: Englisch
    Materialart: reportzib , doc-type:preprint
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  • 16
    Publikationsdatum: 2020-11-13
    Beschreibung: Nachdem mit der KOBV-Suchmaschine die Online-Recherche in den wichtigsten Berliner und Brandenburgischen Bibliotheken realisiert ist, gehört der Aufbau der Online-Fernleihe als einer neuen, nutzerfreundlichen Dienstleistung zu den drängendsten Desideraten des KOBV. Dem Nutzer soll ein komfortabler Service geboten werden, der ihm im Anschluss an eine erfolgreiche Recherche die nahtlose - per Knopfdruck ausgelöste - Fernleih-Bestellung auf das gewünschte Medium erlaubt. Gleichzeitig trägt die Ablösung des traditionellen, per Post und Bücherauto versandten Roten Fernleihscheines durch eine sekundenschnelle Online-Kommunikation zu einer erheblichen Beschleunigung des Fernleih-Verfahrens bei. Der KOBV beteiligt sich an der Initiative der deutschen Bibliotheksverbünde zur Automatisierung und Beschleunigung der Fernleihe. Die Realisierung soll im KOBV in einem zweistufigen Verfahren erfolgen: (1) verbundinterne Fernleihe im KOBV und (2) verbundübergreifende Fernleihe in der Zusammenarbeit mit den anderen Verbünden. Eine Verbund-Fernleih-Software für den KOBV muss insbesondere den KOBV-spezifischen Gegebenheiten genügen, die in dieser Form in den anderen deutschen Verbünden nicht anzutreffen sind. Im Jahre 2001 hat eine KOBV-Arbeitsgruppe Spezifikationen für eine Verbund-Fernleih-Software erarbeitet, in der die Besonderheiten des KOBV mit berücksichtigt sind. Beim Aufbau der automatisierten Fernleihe als einer regulären KOBV-Dienstleistung geht es nicht allein darum, einen schnellen, komfortablen Service für Nutzer einzurichten, sondern darüber hinaus um eine weitreichende Rationalisierung innerhalb der Bibliotheken. Das vorliegende Spezifikationspapier zielt auf beide Faktoren ab, indem es die Fernleihe als integrierten Dienst entwirft, der von der Bestellung bis zur Bereitstellung des Mediums in der gebenden Bibliothek automatisiert - ohne manuelles Eingreifen der Fernleihstelle - abläuft: die jetzige manuell durchgeführte Fernleihe wird durch die automatisierte Fernleihe abgelöst.
    Schlagwort(e): ddc:000
    Sprache: Deutsch
    Materialart: reportzib , doc-type:preprint
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  • 17
    Publikationsdatum: 2020-12-14
    Beschreibung: In the online traveling salesman problem $OLTSP$ requests for visits to cities arrive online while the salesman is traveling. We study the $F{\_max}-OLTSP$ where the objective is to minimize the maximum flow time. This objective is particularly interesting for applications. Unfortunately, there can be no competitive algorithm, neither deterministic nor randomized. Hence, competitive analysis fails to distinguish online algorithms. Not even resource augmentation which is helpful in scheduling works as a remedy. This unsatisfactory situation motivates the search for alternative analysis methods. We introduce a natural restriction on the adversary for the $F{\_max}-OLTSP$ on the real line. A \emph{non-abusive adversary} may only move in a direction if there are yet unserved requests on this side. Our main result is an algorithm which achieves a constant competitive ratio against the non-abusive adversary.
    Schlagwort(e): ddc:000
    Sprache: Englisch
    Materialart: reportzib , doc-type:preprint
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  • 18
    Publikationsdatum: 2016-06-30
    Beschreibung: While attribute-value pairs are a popular method to name objects, information retrieval from those attribute-based namespaces is not an easy task. The user has to recall correct attribute names and values and master the syntax and semantics of query formulation. This paper describes hierarchical structures in attribute-based namespaces, shows how to extract them efficiently and evaluates the quality of these structures in an user experiment. It proposes an user interface for browsing attribute-named object sets which makes this task resemble todays file-system browsers and compares the usability of this interface to normal form-based methods in an user study.
    Schlagwort(e): ddc:000
    Sprache: Englisch
    Materialart: reportzib , doc-type:preprint
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  • 19
    Publikationsdatum: 2014-02-26
    Beschreibung: In this paper, we quantify and discuss the physical and surface chemical processes leading to the formation, temporal evolution and sedimentation of dust grains in brown dwarf and giant gas planet atmospheres: nucleation, growth, evaporation and gravitational settling. Considering dust particles of arbitrary sizes in the different hydrodynamical regimes (free molecular flow, laminar flow, turbulent flow), we evaluate the equilibrium drift velocities (final fall speeds) and the growth rates of the particles due to accretion of molecules. We show that a depth-dependent maximum size of the order of $a_{\rm max}\!\approx\!1\,\mu{\rm m\,(upper\ regions)} \ldots 100\,\mu{\rm m\,(lower\ regions)}$ exists, which depends on the condensate and the stellar parameters, beyond which gravitational settling is faster than growth. Larger particles can probably not be formed and sustained in brown dwarf atmospheres. We furthermore argue that the acceleration towards equilibrium drift is always very fast and that the temperature increase of the grains due to the release of latent heat during the growth process is negligible. Based on these findings, we formulate the problem of dust formation coupled to the local element depletion/enrichment of the gas in brown dwarf atmospheres by means of a system of partial differential equations. These equations state an extension of the moment method developed by Gail\plus Sedlmayr\,(1988) with an additional advective term to account for the effect of size-dependent drift velocities of the grains. A dimensionless analysis of the new equations reveals a hierarchy of nucleation $\to$ growth $\to$ drift $\to$ evaporation, which characterises the life cycle of dust grains in brown dwarf atmospheres. The developed moment equations can be included into hydrodynamics or classical stellar atmosphere models. Applications of this description will be presented in a forthcoming paper of this series.
    Schlagwort(e): ddc:000
    Sprache: Englisch
    Materialart: reportzib , doc-type:preprint
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  • 20
    Publikationsdatum: 2021-01-21
    Beschreibung: Global grid environments do not only provide massive aggregated computing power but also an unprecedented amount of distributed storage space. Unfortunately, dynamic changes caused by component failures, local decisions, and irregular data updates make it difficult to efficiently use this capacity. In this paper, we address the problem of improving data availability in the presence of unreliable components. We present an analytical model for determining an optimal combination of distributed replica catalogs, catalog sizes, and replica servers. Empirical simulation results confirm the accuracy of our theoretical analysis. Our model captures the characteristics of highly dynamic environments like peer-to-peer networks, but it can also be applied to more centralized, less dynamic grid environments like the European {\em DataGrid}.
    Schlagwort(e): ddc:000
    Sprache: Englisch
    Materialart: reportzib , doc-type:preprint
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  • 21
    Publikationsdatum: 2021-01-22
    Beschreibung: Das Management von großen Datenmengen spielt eine immer wichtigere Rolle, wie aktuelle Entwicklungen in der Hochenergiephysik [2] zeigen. Für das DataGrid-Projekt zum Beispiel ist es notwendig, große Datenmengen auf mehrere Rechenzentren in Europa zu verteilen und die Daten untereinander zu synchronisieren. Auch innerhalb von Clustern gewinnen mit zunehmender Anzahl der Knoten Werkzeuge zur effizienten Synchronisation und Verteilung von Daten an Bedeutung. Im Rahmen dieser Arbeit wurde ein effizientes Verfahren zur Synchronisation von verteilten Verzeichnisstrukturen entwickelt und implementiert. Mit diesem Verfahren ist es möglich, unabhängige Änderungen an beliebigen Repositories gleichzeitig durchzuführen. Das Verfahren benötigt keine zentrale Instanz, wodurch eine gegenüber vielen existierenden Verfahren verbesserte Skalierbarkeit erreicht werden konnte. Dabei wurden Erkenntnisse aus der Graphentheorie eingesetzt und weiterentwickelt, um die Netzwerktopolo-gie und -handbreiten zwischen den Rechnern zu berücksichtigen. Durch die Verwendung einer Offline-Synchronisation werden Änderungen erst dann an andere Rechner propagiert, wenn der Nutzer dies anstößt. Das kann zum Beispiel nach einer abgeschlossenen Transaktion, die Änderungen an mehreren Dateien beinhaltet, angemessen sein.
    Beschreibung: Current developments in high energy physics [2] show that the management of large datasets plays an important role. For the DataGrid project it is necessary to distribute large datasets over several computing centers all over Europe and to synchronize these datasets. Within clusters tools for efficient synchronization and distribution of data become more important, too. In this thesis, a method to synchronize distributed directory structures was developed and implemented which makes it possible to perform independent changes to arbitrary repositories simultaneously. This method needs no central instance and therefore the presented system achieves a better scalability than many existing systems. Knowledge from graph theory was used and improved to take the network topology and the network bandwidth between the computers into account. By using offline synchronization, changes will only be propagated when the user initiates it. This can be reasonable after a completed transaction which consists of changes on several files.
    Schlagwort(e): ddc:000
    Sprache: Deutsch
    Materialart: masterthesis , doc-type:masterThesis
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  • 22
    Publikationsdatum: 2020-11-17
    Beschreibung: An instance of the \emph{maximum coverage} problem is given by a set of weighted ground elements and a cost weighted family of subsets of the ground element set. The goal is to select a subfamily of total cost of at most that of a given budget maximizing the weight of the covered elements. We formulate the problem on graphs: In this situation the set of ground elements is specified by the nodes of a graph, while the family of covering sets is restricted to connected subgraphs. We show that on general graphs the problem is polynomial time solvable if restricted to sets of size at most~$2$, but becomes NP-hard if sets of size~$3$ are permitted. On trees, we prove polynomial time solvability if each node appears in a fixed number of sets. In contrast, if vertices are allowed to appear an unbounded number of times, the problem is NP-hard even on stars. We finally give polynomial time algorithms for special cases where the subgraphs form paths and the host graph is a line, a cycle or a star.
    Schlagwort(e): ddc:000
    Sprache: Englisch
    Materialart: reportzib , doc-type:preprint
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  • 23
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    Publikationsdatum: 2014-02-26
    Beschreibung: Hinter der für den Uneingeweihten etwas kryptischen Frage "P = NP?" verbirgt sich das derzeit wichtigste Problem der Komplexitätstheorie. Dieser Artikel erläutert einige Aspekte der Theorie und erklärt informell, was "P = NP?" bedeutet. Es geht nicht nur um komplizierte algorithmische Mathematik und Informatik, sondern um grundsätzliche Fragen unserer Lebensumwelt. Kann man vielleicht beweisen, dass es für viele Probleme unseres Alltags keine effizienten Lösungsmethoden gibt?
    Schlagwort(e): ddc:000
    Sprache: Deutsch
    Materialart: reportzib , doc-type:preprint
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  • 24
    Publikationsdatum: 2020-03-11
    Beschreibung: The Cooperative Library Network Berlin-Brandenburg (KOBV) has set the development of a genuine library information portal for the two German Lander (federal states) Berlin and Brandenburg as its main task for the next years. This joined effort is driven by the vision of an user friendly Internet information portal which is accessible anytime, from anywhere in the world. The idea of a regional information portal can be understood as the logically consistent development of the basic ideas of the KOBV. Starting in 1997, the consortia has set the implementation of a virtual OPAC instead of a physical union catalogue as its goal. The result was the KOBV-Search Engine which already has some qualities of a portal itself. The paper begins with initial remarks about the German library world, which do form the background for the project and its initiator - the KOBV consortia. After this preliminary part, different types of portals are introduced. The basic features of the KOBV-Search Engine as one of the cornerstones of the future portal are discussed in the following. The information portal will be much richer in content and services for the end-user. Two aspects are focused on in more detail: the presentation of resources, which becomes a compelling requirement because of the broader range of content and the personalization of services, as one important feature to suit user's individual needs.
    Schlagwort(e): ddc:000
    Sprache: Englisch
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  • 25
    Publikationsdatum: 2019-01-29
    Beschreibung: The paper presents a particle method framework for resolving molecular dynamics. Error estimators for both the temporal and spatial discretization are advocated and facilitate a fully adaptive propagation. For time integration, the implicit trapezoidal rule is employed, where an explicit predictor enables large time steps. The framework is developed and exemplified in the context of the classical Liouville equation, where Gaussian phase-space packets are used as particles. Simplified variants are discussed shortly, which should prove to be easily implementable in common molecular dynamics codes. A concept is illustrated by numerical examples for one-dimensional dynamics in double well potential.
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    Sprache: Englisch
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  • 26
    Publikationsdatum: 2019-01-29
    Beschreibung: The paper deals with three different Newton algorithms that have recently been worked out in the general frame of affine invariance. Of particular interest is their performance in the numerical solution of discretized boundary value problems (BVPs) for nonlinear partial differential equations (PDEs). Exact Newton methods, where the arising linear systems are solved by direct elimination, and inexact Newton methods, where an inner iteration is used instead, are synoptically presented, both in affine invariant convergence theory and in numerical experiments. The three types of algorithms are: (a) affine covariant (formerly just called affine invariant) Newton algorithms, oriented toward the iterative errors, (b) affine contravariant Newton algorithms, based on iterative residual norms, and (c) affine conjugate Newton algorithms for convex optimization problems and discrete nonlinear elliptic PDEs.
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    Sprache: Englisch
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  • 27
    Publikationsdatum: 2014-02-26
    Beschreibung: In Analogie zu den Elektrizitätsnetzen electricity grid), von denen die technische Revolution ausging, wurde der Begriff Computational Grid (kurz Grid) geprägt. Ein wichtiger Bestandteil des Systems liegt im benutzerfreundlichen Zugang und der koordinierten Nutzung der weltweit verteilten Speicherressourcen und Rechnerkapazitäten. Bei der Entwicklung dazu notwendiger Technologien und Software (Middleware) profitiert man von Kenntnissen und Erfahrungen bei der Entwicklung verteilter Algorithmen, dem Software-Engineering und dem Supercomputing.
    Schlagwort(e): ddc:000
    Sprache: Deutsch
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  • 28
    Publikationsdatum: 2020-02-11
    Beschreibung: In this article we study the problem of designing a nation-wide communication network. Such networks usually consist of an access layer, a backbone layer, and maybe several intermediate layers. The nodes of each layer must be connected to those of the next layer in a tree-like fashion. The backbone layer has to satisfy certain survivability and routing constraints. Given the node locations, the demands between them, the possible connections and hardware configurations, and various other technical and administrational constraints, the goal is to decide, which node is assigned to which network level, how the nodes are connected, what hardware must be installed, and how traffic is routed in the backbone. Mixed integer linear programming models and solution methods are presented for both the access and the backbone network design problem. The focus is on the design of IP-over-SDH networks, but the access network design model and large parts of the backbone network design models are general and also applicable for other types of communication networks. Results obtained with these methods in the planning of the German research network are presented.
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    Sprache: Englisch
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  • 29
    Publikationsdatum: 2021-02-19
    Beschreibung: We present an online algorithm for a real-world vehicle dispatching problem at ADAC, the German Automobile Association.
    Schlagwort(e): ddc:000
    Sprache: Englisch
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  • 30
    Publikationsdatum: 2020-03-11
    Beschreibung: Eine fremddatengestützte Katalogisierung bedeutet für die einzelne Bibliothek unbestritten eine Zeit- und Kostenersparnis. Dieser Report beleuchtet die unterschiedlichen Faktoren technischer und organisatorischer Natur, die die Fremddatennutzung in der dezentralen Struktur des Kooperativen Bibliotheksverbundes Berlin-Brandenburg (KOBV) beeinflussen. Die Ausführungen stützen sich im Wesentlichen auf eine Umfrage, die die Autoren im Mai / Juni 2002 unter KOBV-Mitgliedsbibliotheken zum Thema Fremddatennutzung durchgeführt haben. Dargelegt wird, wie komfortabel die in den KOBV-Bibliotheken eingesetzten Bibliotheksinformationssysteme eine fremddatengestützte Katalogisierung erlauben. Diskutiert wird zudem die Software ZACK, die sich als Alternative zu einem eigenen Z39.50-Client zur Datenübernahme anbietet. Erstmals seit Bestehen des Verbundes werden Zahlen veröffentlicht über den Anteil der Bibliotheken, die Fremddaten nutzen und denjenigen, die dieses Angebot nicht wahrnehmen. Dabei wird die Fremddatenutzung differenziert sowohl für den Bereich der Neuaufnahmen als auch für die Retrokatalogisierung. In der weiteren Analyse werden zusätzliche Aspekte betrachtet wie z.B. die verfügbaren bzw. gewünschten Datenbanken im Verhältnis zum sprachlichen Spektrum des erworbenen Katalogisierungsgutes. Eingegangen wird auch auf die von den Bibliotheken genannten Hauptproblemen und die gewünschten zusätzlichen Serviceleistungen auf Seiten der KOBV-Verbundzentrale. Als Ergebnis dieses Status-Quo-Berichts legt das Autorenteam eine Reihe von Empfehlungen vor, die darauf abzielen, auch für KOBV-Bibliotheken in Zukunft eine Fremddatennutzungsquote von 70 - 75 % zu erreichen.
    Schlagwort(e): ddc:000
    Sprache: Deutsch
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  • 31
    facet.materialart.
    Unbekannt
    Publikationsdatum: 2014-02-26
    Beschreibung: Substellar atmospheres are cool and dense enough that dust forms very efficiently. As soon as these particles are formed, they sizedependently precipitate due to the large gravity of the objects. Arriving in hot atmospheric layers, the dust evaporates and enriches the gas by those elements from which it has formed. The upper atmospheric layers are depleted by the same elements. Non-continuous and spatially inhomogeneous convective element replenishment, generating a turbulent fluid field, completes the circuit of dust. The formation of dust in substellar atmosphere is described by extending the classical theory of Gail\plus Sedlmayr for the case of different gas and dust velocities. Turbulence is modeled in different scale regimes which reveals turbulence as trigger for dust formation in hot environments. Both mechanisms cause the dust to be present in else wise dust-hostile region: precipitation transports the dust into hot regions, and turbulence allows the formation of dust in there.
    Schlagwort(e): ddc:000
    Sprache: Englisch
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  • 32
    Publikationsdatum: 2014-02-26
    Beschreibung: The talk given by the author at the CRM workshop on Superintegrability in Sep.\ 2002 and this related paper report on work in two subjects. One is the collaboration with Vladimir Sokolov and Takayuki Tsuchida in an effort to classify polynomial integrable vector evolution equations. The other is the computer algebra package {\sc Crack} which did the main computations in solving large bi-linear algebraic systems. Although originally designed to solve over-determined systems of partial differential equations a number of extensions made {\sc Crack} a powerful tool for solving systems of bi-linear algebraic equations. Such systems turn up in many different classification problems some of which were investigated by other participants of this workshop. Two additional applications are outlined. In the talk on which this article is based a method to reduce the length of equations was presented which proved to be useful in solving the bi-linear algebraic systems. Due to numerous asked questions about the computer program, a more complete overview is given in the appendix.
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    Sprache: Englisch
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  • 33
    Publikationsdatum: 2020-11-13
    Beschreibung: Die KOBV-Suchmaschine hat seit ihrer Inbetriebnahme Ende 1999 entscheidend zur Verbesserung der Informationsinfrastruktur in Berlin und Brandenburg beigetragen. Auf der Basis der offenen Plattform KOBV-Suchmaschine wird die KOBV-Zentrale gemeinsam mit den Bibliotheken in den nächsten Jahren das Dienstleistungsangebot des KOBV und seiner Bibliotheken kontinuierlich erweitern. Dabei sollen die Prinzipien des KOBV - Offenheit, Heterogenität und Dezentralität auf technischer und organisatorischer Ebene - gewahrt bleiben. Die einzelnen KOBV-Bibliotheken werden sich mit ihren Angeboten in unterschiedlicher Weise im Web positionieren. Die Integration auf regionaler Ebene kann und soll die lokalen Angebote nicht künstlich vereinheitlichen. Das kooperative Portal, das in der Region aufgebaut wird, ist als System geplant, in dem zentrales Portal und lokale Portale nicht hierarchisch einander zugeordnet, sondern miteinander vernetzt sind. Das \glqq KOBV-Informationsportal \grqq soll in der KOBV-Zentrale im Rahmen eines wissenschaftlichen Projektes von Mitte 2001 bis Ende 2003 aufgebaut werden. Das vorliegende Papier gibt einen ersten allgemeinen Einblick, welche Funktionen das \glqq KOBV-Informationsporta \grqq umfassen soll und stellt die Teilprojekte der 1. Stufe vor.
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  • 34
    Publikationsdatum: 2014-11-10
    Beschreibung: Oriented matroids are combinatorial structures that encode the combinatorics of point configurations. The set of all triangulations of a point configuration depends only on its oriented matroid. We survey the most important ingredients necessary to exploit oriented matroids as a data structure for computing all triangulations of a point configuration, and report on experience with an implementation of these concepts in the software package TOPCOM. Next, we briefly overview the construction and an application of the secondary polytope of a point configuration, and calculate some examples illustrating how our tools were integrated into the {\sc polymake} framework.
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    Sprache: Englisch
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  • 35
    Publikationsdatum: 2014-11-10
    Beschreibung: For all perfect graphs, the stable set polytope STAB$(G)$ coincides with the fractional stable set polytope QSTAB$(G)$, whereas STAB$(G) \subset$ QSTAB$(G)$ holds iff $G$ is imperfect. Padberg asked in the early seventies for ``almost'' perfect graphs. He characterized those graphs for which the difference between STAB$(G)$ and QSTAB$(G)$ is smallest possible. We develop this idea further and define three polytopes between STAB$(G)$ and QSTAB$(G)$ by allowing certain sets of cutting planes only to cut off all the fractional vertices of QSTAB$(G)$. The difference between QSTAB$(G)$ and the largest of the three polytopes coinciding with STAB$(G)$ gives some information on the stage of imperfectness of the graph~$G$. We obtain a nested collection of three superclasses of perfect graphs and survey which graphs are known to belong to one of those three superclasses. This answers the question: which graphs are ``almost'' perfect?
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    Sprache: Englisch
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  • 36
    Publikationsdatum: 2020-11-13
    Beschreibung: Die Automatisierung von innerbetrieblicher Logistik erfordert -- über die physikalische Steuerung von Geräten hinaus -- auch eine effiziente Organisation der Transporte: ein Aufgabenfeld der kombinatorischen Optimierung. Dieser Artikel illustriert anhand von konkreten Aufgabenstellungen die Online-Problematik (unvollständiges Wissen) sowie die Echtzeit-Problematik (beschränkte Rechenzeit), auf die man in der innerbetrieblichen Logistik trifft. Der Text gibt einen Überblick über allgemeine Konstruktionsprinzipien für Online-Algorithmen und Bewertungsmethoden, die bei der Entscheidung helfen, welche Algorithmen für eine vorliegende Problemstellung geeignet sind.
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  • 37
    facet.materialart.
    Unbekannt
    Publikationsdatum: 2014-11-10
    Beschreibung: \We discuss a nested collection of three superclasses of perfect graphs: near-perfect, rank-perfect, and weakly rank-perfect graphs. For that, we start with the description of the stable set polytope for perfect graphs and allow stepwise more general facets for the stable set polytopes of the graphs in each superclass. Membership in those three classes indicates how far a graph is away from being perfect. We investigate for webs and antiwebs to which of the three classes they belong. We provide a complete description of the facets of the stable set polytope for antiwebs (with help of a result due to Shepherd on near-bipartite graphs). The main result is that antiwebs are rankperfect.
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    Sprache: Englisch
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  • 38
    Publikationsdatum: 2021-01-21
    Beschreibung: \textsf{\itshape{GuiGen}} is a comprehensive set of tools for creating customized graphical user interfaces (GUIs). It draws from the concept of computing portals, which are here seen as interfaces to application-specific computing services for user communities. While \textsf{\itshape{GuiGen}} was originally designed for the use in computational grids, it can be used in client/server environments as well. Compared to other GUI generators, \textsf{\itshape{GuiGen}} is more versatile and more portable. It can be employed in many different application domains and on different target platforms. With \textsf{\itshape{GuiGen}}, application experts (rather than computer scientists) are able to create their own individually tailored GUIs.
    Schlagwort(e): ddc:000
    Sprache: Englisch
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  • 39
    Publikationsdatum: 2014-02-26
    Beschreibung: The purpose of the paper is to formulate and use syzygies for systems of linear PDEs. The computation of an equivalent of a GCD for linear partial differential operators will save us their factorization which is otherwise only possible algorithmically in special cases. After showing the computation with the new and the traditional method and comparing both in the next three sections, the algorithm is explained in general and an overview is given.
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    Sprache: Englisch
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  • 40
    Publikationsdatum: 2020-11-13
    Beschreibung: Telekommunikation ist seit Jahren \glqq in\grqq. Zunächst gab es einen enormen Aufschwung; neue Technologien und Dienste haben eine überwältigende, nicht vorhersehbare Akzeptanz gefunden. Derzeit ist -- ausgelöst durch die UMTS-Lizenzversteigerungen, Rezessions- und Sättigungstendenzen -- eine Krise zu verzeichnen. Viele (auch wir) sind davon überzeugt, dass technischer Fortschritt und nützliche Dienste demnächst die Stimmung wieder ändern werden. Wenigen ist allerdings bewusst, welche Rolle Mathematik bei der Entwicklung und dem effizienten Einsatz vieler der neuen Kommunikationstechnologien spielt. In diesem Artikel soll kein Überblick über diesen umfangreichen Themenkreis gegeben werden. Wir zeigen lediglich an einem konkreten Beispiel aus dem Mobilfunk, der Frequenzplanung in GSM-Funknetzen, was man durch geeignete Modellierung der praktischen Fragestellung und den Einsatz problemadäquater Algorithmen erreichen kann.
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    Sprache: Deutsch
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  • 41
    Publikationsdatum: 2020-03-09
    Beschreibung: Wir beschreiben einen Ansatz zur integrierten Umlauf- und Dienstplanung im öffentlichen Nahverkehr. Der Ansatz zielt auf die Verbesserung des Gesamtwirkungsgrades dieser beiden Planungsschritte und auf die besondere Planungsproblematik im Regionalverkehr. Wir entwickeln dazu mathematische Optimierungstechniken für den Einsatz in den Planungssystemen MICROBUS II und DIVA.
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    Sprache: Deutsch
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  • 42
    Publikationsdatum: 2014-02-26
    Beschreibung: A graph property is called elusive (or evasive) if every algorithm for testing this property has to read in the worst case $n\choose 2$ entries of the adjacency matrix of the given graph. Several graph properties have been shown to be elusive, e.g. planarity (Best et al) or $k$-colorability (Bollobas). A famous conjecture of Karp says that every non-trivial monotone graph property is elusive. We prove that a non-monotone but hereditary graph property is elusive: perfectness.
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    Sprache: Englisch
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  • 43
    Publikationsdatum: 2014-02-26
    Beschreibung: Recently, a novel approach for the analysis of molecular dynamics on the basis of a transfer operator has been introduced. Therein conformations are considered to be disjoint metastable clusters within position space of a molecule. These clusters are defined by almost invariant characteristic functions that can be computed via {\em Perron Cluster} analysis. The present paper suggests to replace crisp clusters with {\em fuzzy} clusters, i.e. to replace characteristic functions with membership functions. This allows a more sufficient characterization of transiton states between different confor conformations and therefore leads to a better understanding of molecular dynamics. Fur thermore, an indicator for the uniqueness of metastable fuzzy clusters and a fast algorithm for the computation of these clusters are described. Numerical examples are included.
    Schlagwort(e): ddc:000
    Sprache: Englisch
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  • 44
    Publikationsdatum: 2019-01-29
    Beschreibung: The paper provides a detailed analysis of a short step interior point algorithm applied to linear control constrained optimal control problems. Using an affine invariant local norm and an inexact Newton corrector, the well-known convergence results from finite dimensional linear programming can be extended to the infinite dimensional setting of optimal control. The present work complements a recent paper of Weiser and Deuflhard, where convergence rates have not been derived. The choice of free parameters, i.e. the corrector accuracy and the number of corrector steps, is discussed.
    Schlagwort(e): ddc:000
    Sprache: Englisch
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  • 45
    Publikationsdatum: 2017-02-21
    Beschreibung: Pseudo--transient continuation methods are quite popular for the numerical solution of steady state problems, typically in PDEs. They are based on an embedding into a time dependent initial value problem. In the presence of dynamical invariants the Jacobian matrix of the nonlinear equation system is bound to be singular. The paper presents a convergence analysis which takes this property into account -- in contrast to known approaches. On the basis of the new analysis adaptive algorithms are suggested in detail. These include a variant with Jacobian approximations as well as inexact pseudo--transient continuation, both of which play an important role in discretized PDEs. Numerical experiments are left to future work.
    Schlagwort(e): ddc:000
    Sprache: Englisch
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  • 46
    Publikationsdatum: 2014-02-26
    Beschreibung: A beautiful result of Bröcker and Scheiderer on the stability index of basic closed semi-algebraic sets implies, as a very special case, that every $d$-dimensional polyhedron admits a representation as the set of solutions of at most $d(d+1)/2$ polynomial inequalities. Even in this polyhedral case, however, no constructive proof is known, even if the quadratic upper bound is replaced by any bound depending only on the dimension. Here we give, for simple polytopes, an explicit construction of polynomials describing such a polytope. The number of used polynomials is exponential in the dimension, but in the 2- and 3-dimensional case we get the expected number $d(d+1)/2$.
    Schlagwort(e): ddc:000
    Sprache: Englisch
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  • 47
    Publikationsdatum: 2014-11-10
    Beschreibung: TOPCOM is a package for computing triangulations of point configurations and oriented matroids. For example, for a point configuration one can compute the chirotope, components of the flip graph of triangulations, enumerate all triangulations. The core algorithms implemented in TOPCOM are described, and implentation issues are discussed.
    Schlagwort(e): ddc:000
    Sprache: Englisch
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  • 48
    Publikationsdatum: 2020-11-13
    Beschreibung: A model for the optimisation of the location and configuration of base stations in a UMTS network is described. The focus is primarily on modelling the configuration problem sufficiently accurate using mixed-integer variables and (essentially) linear constraints. These constraints reflect the limited downlink code capacity in each cell, the interference limitations for successful up- and downlink transmissions, the need for sufficiently strong (cell) pilot signals, and the potential gain for mobiles from being in soft(er) hand-over. It is also explained how to use the model as a basis for rating network configurations.
    Schlagwort(e): ddc:000
    Sprache: Englisch
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  • 49
    Publikationsdatum: 2016-06-09
    Beschreibung: Computational drug design studies molecular recognition in the {\em virtual lab}. The arising Hamiltonian dynamics is known to be chaotic and ill-conditioned already after picoseconds, whereas times are $msec$ up to $min$. Classical molecular dynamics with long term trajectory computation gives, at best, information about time and statistical ensemble averages. The present paper surveys a recent new modeling approach called {\em conformational dynamics}, which is due to the author and Ch. Schütte. This approach achieves information about the dy time scales by telescoping a short term deterministic model with a statistical model. Examples of small biomolecules are included.
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    Sprache: Englisch
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  • 50
    Publikationsdatum: 2021-02-19
    Beschreibung: Combinatorial online optimization is an area with lots of applications and potential for significant progress, both in theory and practice. In this short note we sketch the ADACproblem, a typical large-scale online optimization problem, discuss some theoretical and pratical issues coming up, and explain, very briefly, how we approach this problem mathematically. Online problems are a battlefield of heuristics with many strong claims about their solution quality. We indicate that a stronger problem orientation and the use of a little more mathematics may yield.
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    Sprache: Englisch
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  • 51
    Publikationsdatum: 2014-02-26
    Beschreibung: A subset ${\cal C}$ of the power set of a finite set $E$ is called cardinality homogeneous if, whenever ${\cal C}$ contains some set $F$, ${\cal C}$ contains all subsets of $E$ of cardinality $|F|$. Examples of such set systems ${\cal C}$ are the sets of circuits and the sets of cycles of uniform matroids and the sets of all even or of all odd cardinality subsets of $E$. With each cardinality homogeneous set system ${\cal C}$, we associate the polytope $P({\cal C})$, the convex hull of the incidence vectors of all sets in ${\cal C}$, and provide a complete and nonredundant linear description of $P({\cal C})$. We show that a greedy algorithm optimizes any linear function over $P({\cal C})$, give an explicit optimum solution of the dual linear program, and provide a polynomial time separation algorithm for the class of polytopes of type $P({\cal C})$.
    Schlagwort(e): ddc:000
    Sprache: Englisch
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  • 52
    facet.materialart.
    Unbekannt
    Publikationsdatum: 2014-02-26
    Beschreibung: Die Bibliotheken des KOBV haben im Jahr 2001 die Entwicklung der KOBV-Suchmaschine zu einem gemeinsamen Informationsportal Berlin-Brandenburg und den Aufbau lokaler Bibliotheksportale als Hauptentwicklungsziele des KOBV definiert. Diese Informationsportale sollen mit Standardsoftware realisiert werden. Um die Auswahl eines Systems zu unterstützen, wurde in der Zentrale des KOBV ausgewählte Systeme untersucht. In der Arbeit werden zahlreiche Kriterien vorgestellt, auf Grund derer die betreffenden Systeme beurteilt werden. Die Kriterien umfassen sowohl Aspekte aus der Sicht der Benutzer als auch Kriterien aus der Sicht der Betreiber eines solchen Systems. Wesentliche Funktionen und die Realisierung von verschiedenen Merkmalen werden im Bericht ausführlich beschrieben. Daneben liefert eine Tabelle mit allen betrachteten Kriterien eine Übersicht über vorhandene Merkmale und der Art der Realisierung.
    Schlagwort(e): ddc:000
    Sprache: Deutsch
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  • 53
    Publikationsdatum: 2021-03-16
    Beschreibung: In the cake cutting problem, $n\ge2$ players want to cut a cake into $n$ pieces so that every player gets a ``fair'' share of the cake by his own measure. We describe a protocol with $n-1$~cuts in which each player can enforce to get a share of at least~$1/(2n-2)$. Moreover we show that no protocol with $n-1$~cuts can guarantee a better fraction.
    Schlagwort(e): ddc:000
    Sprache: Englisch
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  • 54
    Publikationsdatum: 2022-07-07
    Beschreibung: We present a new efficient algorithm for the solution of direct time-harmonic scattering problems based on the Laplace transform. This method does not rely on an explicit knowledge of a Green function or a series representation of the solution, and it can be used for the solution of problems with radially symmetric potentials and problems with waveguides. The starting point is an alternative characterization of outgoing waves called \emph{pole condition}, which is equivalent to Sommerfeld's radiation condition for problems with radially symmetric potentials. We obtain a new representation formula, which can be used for a numerical evaluation of the exterior field in a postprocessing step. Based on previous theoretical studies, we discuss the numerical realization of our algorithm and compare its performance to the PML method.
    Schlagwort(e): ddc:000
    Sprache: Englisch
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  • 55
    Publikationsdatum: 2022-07-07
    Beschreibung: The aim of this paper is to develop fast methods for the solution of nonlinear Schrödinger type equations in fiber optics. Using the method of lines we have to solve a stiff system of ordinary differential equations where the eigenvalues of the Jacobian are close to the imaginary axis. This is usually done by a Split Step method. Here we consider the extrapolation of Split Step methods with adaptive order and step size control. For more complicated nonlinearities, in particular stimulated Raman scattering, Split Step methods are less efficient since symmetry is either destroyed or requires much additional effort. In this case we use implicit Runge Kutta formulas of Gauß type. The key point for the efficient implementation of these methods is that the system of nonlinear algebraic equations can be solved without setting up the Jacobian. The proposed methods are compared to other methods, in particular exponential integrators, the method of Marcuse, and the method of Blow and Wood.
    Schlagwort(e): ddc:000
    Sprache: Englisch
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  • 56
    Publikationsdatum: 2022-07-07
    Beschreibung: The work presents a new approach to the numerical solution of time-harmonic and time-dependent scattering problems. We replace Sommerfeld's radiation condition valid for the Helmholtz equation by a more general concept called pole condition. The pole condition is based on the Laplace transform of the exterior solution and allows a characterization of outgoing waves. Both new insight into the analysis of scattering problems as well as new numerical algorithms are obtained.
    Schlagwort(e): ddc:000
    Sprache: Englisch
    Materialart: doctoralthesis , doc-type:doctoralThesis
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  • 57
    ISSN: 1436-2813
    Schlagwort(e): Key Words: small cell neuroendocrine carcinoma ; colorectum ; chemotherapy ; cisplatin ; 5-fluorouracil
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Materialart: Digitale Medien
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  • 58
    ISSN: 1436-2813
    Schlagwort(e): small cell neuroendocrine carcinoma ; colorectum ; chemotherapy ; cisplatin ; 5-fluorouracil
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract We report herein the case of a 46-year-old-man with small cell neuroendocrine carcinoma (NEC) concomitant with large villous adenoma of the rectum, who underwent abdominaoperineal resection with regional lymphnode dissection. The resected specimen was histologically found to contain a small lesion of NEC confined to the submucosa in the large adenoma. A computed tomography scan done 4 months postoperatively revealed recurrences in the liver, lymph nodes, and bone. Therefore, two cycles of sequential intravenous combined chemotherapy with standard doses of cisplatin and 5-fluorouracil (5-FU) were administered, after which the size of each tumor decreased remarkably. Nevertheless, the patient died 8 months after the operation. As there was a fair response of this tumor to the combined chemotherapy of cisplatin and 5-FU, this regimen against NEC of the colon and rectum should be given consideration.
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  • 59
    ISSN: 1436-3305
    Schlagwort(e): Key words: inoperable ; gastric cancer ; chemotherapy ; efficacy criteria ; primary lesions
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Background. We conducted a retrospective study to investigate the adequacy of the Efficacy Criteria for Primary Lesions in the Japanese Classification of Gastric Cancer (Japanese criteria) for evaluating the anti-tumor efficacy of chemotherapies and the relationship between tumor regression and the prognosis of gastric cancer. Methods. The data for 90 patients with inoperable ad-vanced gastric cancer who received various chemotherapies, consisting of fluorinated pyrimidines and cisplatin, were retrospectively analyzed. Based on the Japanese criteria, we investigated the efficacy of the chemotherapies and the relationship between the response in primary lesions and survival. We also compared the efficacy of chemotherapies evaluated by the Japanese criteria to that evaluated by the WHO criteria. Results. All 90 patients were evaluable by the Japanese criteria. The overall response rate was 53.3% (Partial response [PR] in 48 patients and no change + progressive disease [NC + PD] in 42 patients). The primary lesions were classified as measurable (a-lesions) in 27 patients, evaluable but not measurable (b-lesions) in 31 patients, and diffusely infiltrating (c-lesions) in 32 patients. Overall median survival time (MST) was 9.4 months. The MSTs of the responders and non-responders were 12.6 and 7.8 months, respectively. In contrast, by the WHO criteria, 49 patients (54.4%) were evaluable; the other 41 patients had gastric primary lesions alone but were not measurable by WHO criteria. The overall response rate was 67.3% (33/49), and overall MST was 9.4 months. The MSTs of the responders evaluated by both sets of criteria were both 12.6 months. Conclusions. We suggest that the Japanese criteria are useful for evaluating the anti-tumor effect of gastric cancer chemotherapies and that prospective studies to reconfirm their usefulness are warranted in Japan, and in Western countries.
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  • 60
    ISSN: 1569-8041
    Schlagwort(e): advanced colorectal cancer ; chemotherapy ; meta-analysis ; non-operable metastases confined to the liver
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Background: Metastases confined to the liver is a frequent situation in patients with advanced colorectal cancer. For non-operable patients, 5-FU-based chemotherapy is often proposed but the importance of the choice of first line 5-FU regimen remains debatable. Design: In four previously performed meta-analyses, our group had compared bolus intravenous fluoropyrimidines (bolus FU group) with experimental fluoropyrimidines (experimental FU group), consisting of 5-FU plus leucovorin, 5-FU plus methotrexate, continuous infusion 5-FU, or hepatic-artery infusion FUDR. We re-analysed this data set to focus on 1458 patients with non-operable colorectal metastases confined to the liver, randomised in 22 trials. All analyses were stratified by trial and used individual patient data. Results: Median survival times were 11.3 months in the bolus FU group (95% CI: 10.5–12.0 months) compared to 12.7 months in the experimental FU group (95% CI: 12.0–13.1 months). This difference, although clinically small, was statistically significant, with an overall survival hazard ratio of 0.88 (95% CI: 0.79–0.99, P = 0.037). In a multivariate analysis, performance status was the only significant predictor of survival (P 〈 10−4), whereas the statistical significance of allocated treatment was borderline (P = 0.058). Conclusions: The outcome of patient with non-operable colorectal metastases confined to the liver is poor, and mainly driven by their initial performance status. Experimental chemotherapy schedules yield a small improvement in their overall survival, indicating the importance of the choice of first-line chemotherapy.
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  • 61
    ISSN: 1569-8041
    Schlagwort(e): chemotherapy ; gemcitabine ; head and neck tumors ; paclitaxel
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Background: Paclitaxel as monotherapy or in combination with other drugs has demonstrated significant activity in patients with squamous cell carcinoma of the head and neck region (SCCHN). Preclinical studies have shown gemcitabine to be highly active in SCCHN cell lines. Purpose of the study: To evaluate the activity and toxicity of the combination of paclitaxel by three-hour infusion and gemcitabine as first-line chemotherapy in patients with recurrent and/or metastatic head and neck cancer (HNC). Patients and methods: From September 1996 until May 1998, 44 patients with non-nasopharyngeal recurrent and/or metastatic HNC entered the study. There were 37 men and seven women with a median age of 61 years (range 35–79) and a median performance status of 1 (range 0–2). The location of the primary tumor in the majority of them was either the larynx or the oral cavity. Treatment consisted of six cycles of gemcitabine 1100 mg/m2 over 30 min on days 1 and 8 immediately followed on day 1 by paclitaxel 200 mg/m2 by three-hour infusion. The treatment was repeated every three weeks. Results: Twenty-four (55%) patients completed all six cycles of treatment. A total of 205 cycles were administered, 165 (81%) of them at full dose. The median relative dose intensity (DI) of gemcitabine was 0.93 and of paclitaxel 0.95. Except for alopecia, which was universal, grade 3–4 toxicities included neutropenia (21%), thrombocytopenia (5%), anemia (5%), infection (5%), flu-like syndrome (5%) and peripheral neuropathy (2%). Five (11%) patients achieved complete and 13 (30%) partial responses, for an overall response rate of 41%. After a median follow-up of 13 months, the median time to progression was four months and median survival nine months. Conclusions: The combination of paclitaxel and gemcitabine is active and well tolerated in patients with recurrent and/or metastatic HNC – randomized studies comparing this combination with other regimens are warranted.
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  • 62
    ISSN: 1569-8041
    Schlagwort(e): chemotherapy ; mitomycin ; recurrent ; undifferentiated carcinoma of nasopharyngeal type
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Background: This phase-II study was conducted to investigate the potential benefit from the addition of mitomycin to a conventional anthracycline-cisplatin- and 5-fluorouracil-based chemotherapy for recurrent and metastatic undifferentiated carcinoma of nasopharyngeal type (UCNT). Patients and methods: Between July 1989 and December 1991, 44 consecutive patients (M/F 36/8; median age: 45, range 20–72; performance status (PS) 0: 20 patients, PS 1: 14 patients, PS 2: 10 patients) with recurrent or metastatic UCNT were entered in this study after complete clinical, biological, and radiological pre-therapeutic work-ups. Chemotherapy (FMEP regimen) consisted of 800 mg/m2/day 5-fluorouracil in continuous infusion from day 1 to day 4 combined with 70 mg/m2 epirubicin, 10 mg/m2 mitomycin, and 100 mg/m2 cisplatin on day 1, every four weeks for six cycles. Mitomycin was delivered in cycles 1, 3, and 5 only. Eleven patients had isolated loco-regional recurrences, 12 patients had local recurrences associated with distant metastasis, and 21 patients had metastasis only. Toxicity and response were evaluated according to WHO criteria. Toxicity: Grade 3–4 neutropenia was observed in 122 of 212 evaluable cycles (57%) and 39 of 44 patients (89%); febrile neutropenia occurred in 16 patients (36%) and 24 cycles (11.3%). Grade 3–4 thrombocytopenia was observed in 27 patients (61%) and 45 cycles (21%), including 27 of 45 cycles (60%) with mitomycin. Grade 3 anemia was noted in 18 patients (40%) and 23 cycles (11%), including 18 of 23 cycles (78%) with mitomycin. Grade 3–4 mucositis occurred in 25 cycles (11%) and 14 patients (32%), mainly in those previously treated with radiation therapy in the head and neck area. There were four treatment-related deaths (9%); three of them neutropenia-related, and one of cardiac toxicity. Response: Forty-four patients were evaluable for response: There were 23 of 44 objective responses (52%), including six complete responses (13%), and 17 partial responses (38%). Additional radiotherapy was given to 13 patients after documentation of response: Nasopharyngeal tumor + cervical nodes (eight patients) and/or on bone metastasis sites (five patients); mediastinal lymph nodes (one patient). At a median follow-up of 87 months (range 71–100), five patients are alive and in continuous complete remission. The median survival time was 14 months and the median time to progression nine months. Conclusion: The regimen under study is active in recurrent/metastatic UCNT, but associated with excessive toxicity.
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  • 63
    ISSN: 1569-8041
    Schlagwort(e): chemotherapy ; colorectal cancer ; 5-fluorouracil ; folinic acid ; hydroxyurea ; modulation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Background: Hydroxyurea (HU), an inhibitor of ribonucleotide reductase, may potentiate the activity of 5-fluorouracil (5-FU) and folinic acid (FA) by reducing the deoxyribonucleotide pool available for DNA synthesis and repair. However as HU may inhibit the formation of 5-fluoro-2′-deoxyuridine-5′-monophosphate (FdUMP), one of the principal active metabolites of 5-FU, the scheduling of HU may be critical. In vitro experiments suggest that administration of HU following 5-FU, maintaining the concentration in the region of 1 mM for six or more hours, significantly enhances the efficacy of 5-FU. Patients and methods: 5-FU/FA was given as follows: days 1 and 2 – FA 250 mg/m2 (max. 350 mg) over two hours followed by 5-FU 400 mg/m2 by intravenous bolus (ivb) over 15 minutes and subsequently 5-FU 400 mg/m2 infusion (ivi) over 22 hours. HU was administered on day 3 immediately after the 5-FU with 3 g ivb over 15 minutes followed by 12 g ivi over 12 hours. Results: Thirty patients were entered into the study. Median survival was nine months (range 1–51+ months). There were eight partial responses (28%, 95% CI: 13%–47%). The median duration of response was 6.5 (range 4–9 months). Grade 3–4 toxicities included neutropenia (grade 3 in eight patients and grade 4 in five), anaemia (grade 3 in one patient) and diarrhoea (grade 3 in two patients). Neutropenia was associated with pyrexia in two patients. Phlebitis at the infusion site occurred in five patients. The treatment was complicated by pulmonary embolism in one patient and deep venous thrombosis in another. Conclusion: HU administered in this schedule is well tolerated. Based on these results and those of other phase II studies, a randomised phase III study of 5-FU, FA and HU versus 5-FU and FA using the standard de Gramont schedule is recommended.
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  • 64
    ISSN: 1569-8041
    Schlagwort(e): chemotherapy ; cisplatin ; docetaxel ; head and neck cancer ; phase II
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Background: Docetaxel and cisplatin are among the most active antitumor agents in head and neck cancer, and phase I studies found the combination of the two drugs to be feasible. The EORTC ECSG performed a multicenter phase II study in patients with locally advanced, recurrent or metastatic squamous cell carcinoma of the head and neck to evaluate the antitumor efficacy and toxicity of this combination. Patients and methods: Eligibility criteria included written informed consent, a WHO performance status 〈2, life expectancy of 〉12 weeks, and adequate bone marrow, liver and renal function. Neoadjuvant pretreatment with cisplatin-based chemotherapy or prior radiotherapy were allowed. Patients were ineligible if pretreated with taxoids, had CNS involvement, concurrent malignancy, peripheral neuropathy, or no measurable disease. Treatment consisted of docetaxel 100 mg/m2 (one-hour i.v. infusion), followed by cisplatin 75 mg/m2 (three-hour i.v. infusion), repeated every three weeks. Supportive care included hydration, 5HT3- antagonists, and corticosteroids. Results: Forty-four patients (median age 55 years, range 35–76) entered the trial; 41 patients were eligible, 164 cycles of treatment were evaluable for toxicity, and 31 patients for response. Fourteen patients had undergone prior surgery, 15 had received radiotherapy, and five had had chemotherapy. A median number of four treatment cycles (range 1–6) was given. Hematologic and non-hematologic toxicities were common, but hypersensitivity reactions and fluid retention were very infrequent due to corticosteroid prophylaxis. Four patients were taken off the study due to toxicity, and one toxic death occurred due to pneumonia. Among 41 eligible patients, objective responses as confirmed by independent review included six complete remissions and 16 partial remissions, resulting in an overall response rate of 53.7% (95% confidence interval: 37.4%–69.3%). Responses occurred in locally advanced, recurrent and metastatic disease, both in pre- and non-pretreated patients. Of 22 evaluable, non-pretreated patients with locally advanced or metastatic disease, five achieved complete responses, and 14 partial responses. Observed among nine evaluable pretreated patients with locally advanced or metastatic head and neck cancer were one complete response and two partial responses. Conclusion: The combination of docetaxel and cisplatin is feasible and active in locally advanced, recurrent, and metastatic squamous cell carcinoma of the head and neck.
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  • 65
    Digitale Medien
    Digitale Medien
    Springer
    Annals of oncology 10 (1999), S. 3-8 
    ISSN: 1569-8041
    Schlagwort(e): α-interferon ; chemotherapy ; chromogranin A ; octreotide ; receptor scintigraphy ; somatostatin ; surgery
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Neuroendocrine gut and pancreatic tumors are rather rare malignant diseases which has gained increased attraction through the last decennium, possibly through development of new diagnostic and therapeutic methods. Histopathology demonstrating the common neuroendocrine features of these tumors has been the diagnostic corner stone for long, but today it should be supplemented with information about the tumor biology. An excellent biochemical marker which is easy to analyze in serum or plasma is chromogranin A, which is a glycoprotein that is stored and released from neuroendocrine cells. This marker can be used for diagnosis and follow-up of the patients. Somatostatin receptor scintigraphy has been one of the most important diagnostic tools for staging of the disease and also indicating sensitivity to treatment with somatostatin analogues. It is a general agreement that almost every patient should be subjected to this procedure before or during the treatment course. From the therapeutic point of view, surgery is nowadays more extensive aiming at reducing the tumor mass in patients who could not be cured by surgery alone. Other means of tumor reduction is liver dearterialization by embolization with starch spheres. The medical treatment of neuroendocrine tumors has made a real break through with the introduction of somatostatin analogues, particularly octreotide, and today most of the hormonally related symptoms can be controlled by this kind of treatment. Somatostatin analogues have also shown to be inhibitors of tumor growth and the latest development is tumor targeted radioactive treatment with Ytrium or Indium labelled octreotide. Long-acting formulation of somatostatin analogues have come into clinical use and significantly improved quality of life for patients with neuroendocrine tumors. Other means of medical treatment are alpha interferons, which have shown particular effect in patients with midgut carcinoid tumors giving both biochemical and tumor responses. Chemotherapy such as streptozotocin plus 5-fluorouracil (5-FU) or doxorubicin is still considered as first-line treatment in malignant endocrine pancreatic tumors but is combined with concomitant somatostatin analogue treatment. In the future a multimodal treatment will further develop combining different agents and also somatostatin receptor subtype specific analogues will come into clinical use.
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  • 66
    ISSN: 1569-8041
    Schlagwort(e): cancer ; chemotherapy ; colitis ; cytomegalovirus ; docetaxel ; hypopharynx
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract We present the case of a patient with a locally advanced hypopharyngeal carcinoma who developed a severe cytomegalovirus (CMV) colitis after his first chemotherapy course with 5-fluorouracil (5-FU), docetaxel and cisplatin. The most probable cause of his CMV colitis is the impaired immunity during a phase of neutropenia after the chemotherapy. Although there was amelioration of the colitis and clinical status after treatment with ganciclovir, the patient later deteriorated and died due to recurrent bacterial infections. This is the third reported case of CMV colitis treated with ganciclovir in a patient with a solid tumour. It is the first report of CMV colitis after docetaxel containing chemotherapy. Although CMV colitis is most frequently observed in immunosuppressed patients such as those with acquired immune deficiency syndrome (AIDS), transplants and corticosteroid treatment, it has also been reported in less immunosuppressed (elderly, malnourished, ...) and even non-immunosuppressed patients. CMV infection should therefore be included in the differential diagnosis of GI disease in all patients, and when suspected, the clinician should pursue appropriate diagnostic and therapeutic interventions.
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  • 67
    Digitale Medien
    Digitale Medien
    Springer
    Annals of oncology 10 (1999), S. 1389-1392 
    ISSN: 1569-8041
    Schlagwort(e): adenocarcinoma ; chemotherapy ; primary ; unknown
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Background: Adenocarcinoma of unknown primary comprises up to 10% of metastatic malignant disease. With few exceptions this diagnosis carries a very poor prognosis of a few months with minimal survival advantage to chemotherapy. However there is the possibility that chemotherapy can improve symptom control and quality of life. Patients and methods: Forty-four patients with adenocarcinoma of unknown primary received CFTam chemotherapy regimen (5-FU 750 mg/m2/day by protracted infusion for five days, cisplatin 60 mg/m2 once and tamoxifen 20 mg daily on a 21-day cycle). Disease response and toxicity were collected and survival compared to patients who were not treated or who received different chemotherapy regimens. Results: Overall response to CFTam was 27% with a median duration of 10 months (range 4–26 months). The chemotherapy was well tolerated with no grade 4 non-haematological toxicity and only three patients (7%) grade 4 neutropaenia with only two (5%) patients developing sepsis. There were no toxic deaths. Performance status was maintained or improved in responders. Conclusions: CFTam is a well tolerated chemotherapy regimen with similar efficacy to other regimens described in the treatment of adenocarcinoma of unknown primary. In the absence of a significant survival advantage there is a need to conduct randomised trials of chemotherapy versus best supportive care to quantify any improvement in quality of life or symptom control.
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  • 68
    ISSN: 1569-8041
    Schlagwort(e): breast cancer ; chemotherapy ; margins ; radiotherapy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Background: Inadequate surgical excision with residual involvement of resection margins by tumour after breast conservation results in increased local recurrence rates. To reduce this risk positive margins are, therefore, usually excised. Systemic treatment with tamoxifen or chemotherapy reduces local recurrence, along with radiotherapy. However, no studies to date have examined the correlation between chemoendocrine treatment, together with radiotherapy, and local relapse in patients with unexcised involved resection margins, having had breast conservation treatment. Patients and methods: The histopathology reports were reviewed of 184 patients who were treated from June 1991 to August 1995 within our randomised study of neoadjuvant versus adjuvant chemoendocrine therapy with mitozantrone and methotrexate (2M) ± mitomycin-C (3M) and tamoxifen, used concurrently with radiation following conservation surgical treatment. Histological resection margin was considered positive if ductal carcinoma in situ (DCIS) or invasive carcinoma was present microscopically less than 1mm from the excision margin. Results: Although 38% of patients had unexcised microscopically involved margins, local relapse rate as first site of relapse was only 1.9% after a median follow up of 57 months. There was no difference in distant relapse (P = 0.2) and survival (P = 0.5) between the positive and negative margins groups. Conclusions: The presence of positive unexcised margins does not have a significant effect on outcome in patients who are treated with chemoendocrine therapy together with radiotherapy. Further clinical trials are required.
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  • 69
    ISSN: 1569-8041
    Schlagwort(e): aggressive NHL ; chemotherapy ; CHOP ; EPOCH ; phase III randomised trial
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Background: The value of continuous-infusion chemotherapy (EPOCH) vs. the standard CHOP combination was evaluated in 78 patients with previously untreated aggressive non-Hodgkin's lymphoma in a randomized phase III clinical trial. Patients and methods: The EPOCH regimen given to 38 patients consisted of the drugs etoposide (50 mg/m2), vincristine (0.4 mg/m2), and doxorubicin (10 mg/m2), all given in a continuous infusion on days 1–4. Cyclophosphamide (750 mg/m2) was administered on day 6 as i.v. bolus, while prednisone was given orally 60 mg/m2 on days 1–6. Courses were repeated every three weeks. CHOP was given to 40 patients as routinely prescribed. Results: Forty-eight patients were males and thirty were females. Their ages ranged from 19–75 years (median 45 years). Forty-three (55%) had grade 2 and thirty-five (45%) had grade 3 pathologic subtype. Nine patients (12%) presented with stage I, fourteen (18%) with stage II, forty (51%) with stage Ill, and fifteen (19%) with stage IV disease. The different clinico-pathologic characteristics, including international index categories, were comparable in the two groups. The number of courses given ranged between 3 and 9 (median 6) for both the EPOCH and CHOP regimens. Complete remission (CR) was achieved in 19 (50%), and 27 (67%) of the 38 and 40 patients for both the EPOCH and CHOP combinations, respectively. After a median observation time of 27 months, the four-year overall and failure-free survival rates were 42% and 30% for the EPOCH and 71% and 54% for the CHOP regimen (P = 0.006 and 0.1 for the overall and FFS rates, respectively). Toxicities were comparable and were mostly of grades 1 and 2, except for hair loss, hematologic toxicities, and infectious episodes which were more common in the EPOCH group. In the EPOCH group, overall survival rates were 55% vs. 22% (P 〈 0.04) at four years for the low-risk (2 prognostic factors) and high-risk (〉2 factors) groups, respectively. Conclusions: Thus, it may be concluded that continuous-infusion (EPOCH) chemotherapy did not improve treatment outcome over that of the CHOP regimen for aggressive non-Hodgkin's lymphoma patients.
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  • 70
    ISSN: 1569-8041
    Schlagwort(e): autologous stem-cell transplantation ; chemotherapy ; Hodgkin's disease ; relapses
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Background: Despite high-dose therapy and ASCT some patients with aggressive HD fail to achieve long-term survival. Patients and methods: Forty-three patients with induction failure (n = 19) or very unfavorable (UF) relapse (n = 24) from HD were included in a multicentric study of tandem ASCT. They planned to receive two courses of IVA75 with GCSF and blood stem-cell collection. ASCT1 was conditionned with CBV + mitoxantrone (30 mg/m2) and ASCT2 (cytarabine 6 g/m2, melphalan 140 mg/m2 and total body irradiation at 12 Gy or busulfan 16 (n = 4) than 12 mg/kg). After salvage therapy, response 〉50% was observed in 63% of the patients (six patients were included for refractory relapse). Four patients had no ASCT for disease progression; seven patients had only ASCT1 (disease progression, n = 3) and thirty-two patients (74%) received the two ASCT. Results: Hematologic recovery was normal after ASCT1 but delayed platelet recovery was observed after ASCT2 with busulfan in the conditioning regimen. Two VOD with one fatal occured with busulfan at 16 mg/kg and one hemorragic cystis, no further grade 4 toxicity was observed with the reduced doses of busulfan (12 mg/kg). After ASCT2, 83% of these UF patients were in remission and 20% relapsed within the first year. On an intent-to-treat analysis, 22 of 43 patients are in continuous CR (including 8 patients with induction failure). For the whole population (n = 43) and for patients receiving the two ASCT (n = 32), the two-year survival from the date of progression were respectively at 65% and at 74%. Conclusion: double ASCT is feasible in very UF relapse from HD and may lead to some prolonged remission.
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  • 71
    ISSN: 1569-8041
    Schlagwort(e): chemotherapy ; Epstein–Barr virus ; LMP-1 ; peripheral blood stem cells ; T-cell rich B-cell non-Hodgkin's lymphoma (TCRBCL)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract We report the case of a 30-year-old woman who presented with an EBV related hemophagocytic syndrome. After a few months she developed a T-cell rich B-cell non-Hodgkin's lymphoma with liver involvment. Serological data demonstrated a reactivation of the EBV infection. Tumor progression with liver involvement occured during treatment with conventional chemotherapy. Tumor reduction and disappearence of all masses was seen after starting high-dose sequential chemotherapy, followed by an autologous peripheral blood progenitor transplantation. LMP-1 could be amplified in the tumor material by PCR technology, but no LMP-1 expression could be found in the few malignant B-cells with Reed–Sternberg morphology. Sequence analysis of the carboxy terminal of the LMP-1 region revealed the naturally occuring 30 bp deletion variant of the LMP-1 with multiple point mutations within the NF kb region. Since LMP-1 was not expressed in the malignant tumor cells, no evidence could be found, that EBV participated in the tumorigenesis of this case.
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  • 72
    ISSN: 1569-8041
    Schlagwort(e): chemotherapy ; cisplatin ; gemcitabine ; NSCLC ; weekly administration
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Background: The combination of gemcitabine and cisplatin has proven effective in the treatment of advanced non-small-cell lung cancer (NSCLC). However, the optimal schedule for administration of the two drugs has not yet been determined. In this study we evaluated the activity and toxicity of a weekly gemcitabine and cisplatin schedule. Patients and methods: Thirty-six untreated patients with stage IIIB–IV NSCLC entered the study. Treatment consisted of gemcitabine 1000 mg/m2 i.v. and cisplatin 35 mg/m2 i.v., both given weekly on days 1, 8, and 15, followed by one week of rest. Results: Ninety-seven courses (273 weekly administrations) were delivered. The median dose-intensity was 612 mg/m2 per week for gemcitabine (82%) and 21 mg/m2 per week for cisplatin (80%). All 36 of the patients were evaluable for toxicity, and 30 for response. Partial remissions were observed in 12 patients, for an overall response rate of 40% (95% confidence interval (95% CI): 22.5%–57.5%). Most of the partial remissions were seen in IIIB patients (54% of the stage IIIB and 22% of the stage IV patients responded). According to the intent-to-treat principle, the response rate was 33.3% (12 of 36 patients). The median response duration was 9.9 months (range 4–23) and the median survival time 11.8 months (range 1–24). World Health Organization (WHO) grade 3–4 myelotoxicity was: thrombocytopenia in nine patients (25%), neutropenia in six (16.6%) and anemia in six (16.6%); there was very little additional major toxicity. Conclusions: This regimen appears to be active and to have a favourable toxicity profile.
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  • 73
    ISSN: 1569-8041
    Schlagwort(e): chemotherapy ; Ewing's sarcoma ; pregnancy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Ewing's sarcoma of the pelvic bones was diagnosed in a 21-year childbearing woman, raising major medical and ethical problems. The diagnostic and therapeutic approaches during the sixth month of gestation were tailored in order to cure the patient and avoid unnecessary toxicity to the fetus. Ancillary tests included ultrasound and MRI studies of the pelvis. Ifosfamide and adriamycin, premedicated by granisetron, were administered during gestation, and were found to be safe. Cesarean section was the preferred way of delivery since the tumor involved the pelvic bones. The outcome was a disease-free patient and a small healthy baby who is now two years of age.
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  • 74
    Digitale Medien
    Digitale Medien
    Springer
    Annals of oncology 10 (1999), S. 83-91 
    ISSN: 1569-8041
    Schlagwort(e): chemotherapy ; new drugs ; radiotherapy ; small cell lung cancer
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Small cell lung cancers, comprising approximately 20% of lung cancers, are rapidly growing and disseminating carcinomas which are initially chemosensitive but acquire drug resistance during the course of disease. Thus, outcome is poor with median survival of 10-16 months for patients with limited and 7-11 months for patients with extensive disease. Polychemotherapy with established drugs (platins, etoposide, anthracyclines, cyclophosphamide, ifosfamide and Vinca alkaloids) plays the major role in the treatment of this disease and results in overall response rates between 80%-95% for limited disease and 60%-80% for extensive disease. Dose-intensified chemotherapy and high-dose chemotherapy with peripheral blood progenitor cell support were tested in several trials but their exact impact on outcome remains to be determined. New drugs including the taxanes (paclitaxel, docetaxel), the topoisomerase I inhibitors (topotecan, irinotecan), vinorelbine and gemcitabine are currently evaluated in clinical trials. In limited disease, thoracic radiotherapy improves survival and prophylactic cranial irradiation should be administered to those with a reasonable chance of cure.
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  • 75
    ISSN: 1569-8041
    Schlagwort(e): chemotherapy ; necrotising fasciitis ; recurrent inflammation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract We present the case history of a patient with breast carcinoma who developed repeated inflammation at the site of previous necrotising fasciitis following each cycle of intravenous CMF chemotherapy. This complication has not previously been reported.
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  • 76
    ISSN: 1569-8041
    Schlagwort(e): chemotherapy ; gastric cancer ; oral fluoropyrimidine prodrug ; S-1 ; Tegafur
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract We report the case of an unresected, metastatic gastric cancer, which was treated with a very short course of the oral 5-fluorouracil (5-FU) prodrug S-1. The patient had to discontinue chemotherapy during the first treatment cycle due to severe toxicity, but achieved a pathologically confirmed, long-term complete response of her primary tumour, a diffuse-type poorly differentiated adenocarcinoma.
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  • 77
    ISSN: 1569-8041
    Schlagwort(e): advanced disease ; chemotherapy ; cisplatin ; etoposide ; non-small-cell lung cancer
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract The role of chemotherapy in the treatment of advanced non-small-cell lung cancer (NSCLC) has been a subject of debate for many years. Only recently, cisplatin-based combination chemotherapy has been demonstrated to yield a small but definite survival benefit and to improve symptoms, performance status and quality of life in a substantial proportion of advanced NSCLC patients. The cisplatin–etoposide (PE) regimen was developed in the early 1980s and has been one of the standard chemotherapy programs most extensively used in the clinical practice until a few years ago. More recently, several randomized trials have compared the efficacy of new cisplatin-containing combination chemotherapies including Paclitaxel or Gemcitabine with that of PE or PE-like regimens. Preliminary results are encouraging, indicating a small benefit in favor of the last generation of regimens which might therefore replace PE as 'gold standards' in the treatment of advanced NSCLC. However, the costs of these last generation regimens is higher and the entity of the benefit small. Therefore, PE chemotherapy can still be an option in selected situations.
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  • 78
    Digitale Medien
    Digitale Medien
    Springer
    Annals of oncology 10 (1999), S. 89-92 
    ISSN: 1569-8041
    Schlagwort(e): anemia ; chemotherapy ; erythropoietin ; lung cancer ; review ; toxicity
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Main mechanisms involved in the development of chemotherapy-induced anemia are the direct bone marrow damage and the renal impairment with a secondary deficient production of erythropoietin. The first mechanism is induced by almost all cytotoxic drugs whilst the second one has been demonstrated with cisplatin treatment. NSCLC patients are generally treated with platinum-based chemotherapy and then both mechanisms are involved in the development of anemia which can be, as a consequence, more frequent and more severe compared to other cancer patients. Chemotherapy regimens such as MVP (mitomycin, vindesine, platin), cisplatin–etoposide and cisplatin–teniposide induce grade ≥2 anemia in 64%, 46% and 83% of patients, respectively, with grade 3–4 anemia occurring in 29%, 15% and 24% of patients. New chemotherapy regimens are also associated with a high incidence of anemia. Carboplatin–paclitaxel induces grade 3–4 anemia in 34% of patients and 30% of patients need blood transfusions. Similarly, 33% of patients treated with cisplatin-gemcitabine require blood transfusions. Erythropoietin is able to correct anemia in nearly 60%–80% of patients receiving platinum-based chemotherapy and in nearly 40% of patients treated with regimens without platinum compounds, leading to a reduction in blood transfusion requirement. Moreover, erythropoietin is able to prevent anemia development in cancer patients. Due to the high incidence of anemia, erythropoietin may represent an important tool in the supportive care of NSCLC patients. Erythropoietin use is mainly limited by the economic cost and then efforts should be made to identify the subset of patients in whom this supportive therapy is cost-effective. Patient and disease characteristics, factors predicting the probability to be transfused as well as factors predicting the response to erythropoietin can be useful in selecting patients likely to benefit from erythropoietin therapy.
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  • 79
    ISSN: 1569-8041
    Schlagwort(e): chemotherapy ; edatrexate ; paclitaxel ; synergism
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Background: The antifolate edatrexate and the microtubule-stabilizing agent paclitaxel have both demonstrated single-agent activity in lung and breast cancer. In vitro, the sequential combination of edatrexate followed by paclitaxel produced synergistic antitumor effects. This trial was designed to find the maximum tolerated doses of edatrexate and paclitaxel when given every two weeks utilizing this sequential schedule. Patients and methods: Thirty-four patients with solid tumors received edatrexate intravenously on days 1 and 15 and paclitaxel intravenously as a three-hour infusion on days 2 and 16 of each 28-day cycle. Edatrexate was escalated from 40 to 120 mg/m2 and the paclitaxel dose fixed at 135 mg/m2. When the maximum-tolerated dose was not reached, edatrexate was fixed at 120 mg/m2 and paclitaxel escalated to 175 and 210 mg/m2. Results: All 34 patients were assessable. The maximum tolerated doses were 120 mg/m2 of edatrexate and 210 mg/m2 of paclitaxel. Grade 3 myalgia, peripheral neuropathy, leukopenia, and an infusion-related reaction occurred. Eight patients with non-small-cell lung cancer and one with bladder cancer achieved major objective responses. Conclusions: The recommended phase II doses are 120 mg/m2 of edatrexate days 1 and 15 and 175 mg/m2 of paclitaxel as a three-hour infusion days 2 and 16 of a 28 day cycle. These results warrant phase II trials of the combination leading to phase III studies comparing the two drugs to a single agent to confirm the preclinical evidence of synergy.
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  • 80
    ISSN: 1569-8041
    Schlagwort(e): chemotherapy ; multiday vinorelbine–cisplatin ; NSCLC
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Purpose: To evaluate the efficacy of a novel multiday schedule of vinorelbine and cisplatin in patients with advanced NSCLC. Patients and methods: Thirty patients were enrolled, including 27 patients with stage IV disease, and 11 patients with performance status of 2. They received a maximum of four chemotherapy cycles with cisplatin 20 mg/m2/day and vinorelbine 15 mg/m2/day intravenously (i.v.) for four consecutive days, every three weeks, with prophylactic filgrastim. Results: Sixteen patients responded (53%, 95% confidence interval (95% CI): 34%–72%), including two complete and fourteen partial confirmed responses. Median survival for all patients was 8.1 months, with actuarial one-year and two-year survival rates of 40% and 15%. Despite prophylactic filgrastim, the delivered vinorelbine dose intensity of 16.8 mg/m2/week caused febrile neutropenia in 48% of patients (16% of cycles), resulting in one treatment-related death. Common nonhematologic toxicities included delayed emesis, asthenia, and constipation. Conclusions: This multiday vinorelbine–cisplatin schedule is highly active against advanced NSCLC but results in frequent neutropenic complications. The myelotoxicity and antitumor efficacy of vinorelbine in NSCLC patients may be schedule-dependent.
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  • 81
    ISSN: 1569-8041
    Schlagwort(e): aggressive lymphoma ; chemotherapy ; prognostic factors ; randomised trial
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Background: The long-term survival of patients with advanced stage aggressive lymphoma has not improved significantly during the last twenty years. In a randomised trial, the efficacy of MACOP-B, a six-drug weekly chemotherapy regimen, was compared to CHOP, the current standard regimen, in terms of overall and failure-free survival, toxicity and health related quality of life. Patients and methods: Four hundred five patients with aggressive lymphoma, stage II–IV, age 18–67, were randomised to receive either 12 weeks of MACOP-B or 8 courses of CHOP over 24 weeks. Special emphasis was put in the definition of Ann Arbor stage in extranodal disease. A subset of 95 patients also entered a quality of life study, based on the EORTC QLQ-C30. Results: Thirty-one patients were ineligible. Among the remaining 374 patients, the median age was 52 years. According to the age-adjusted International Prognostic Index, 37% were ‘high-intermediate’ or ‘high-risk’ patients. No difference could be demonstrated, either in overall survival (60% at five years in the MACOP-B group and 59% in the CHOP group) or in failure-free survival (47% at five years with MACOP-B and 44% with CHOP). In terms of quality of life, physical function and global quality of life were more impaired in patients receiving MACOP-B, who also exhibited more non-haematological toxicity. Conclusion: No superiority of MACOP-B compared to CHOP could be demonstrated. CHOP remains the treatment of choice in low-risk patients. At present, intensified or experimental treatment should be reserved for high-risk disease.
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  • 82
    Digitale Medien
    Digitale Medien
    Springer
    Journal of molecular medicine 77 (1999), S. 332-338 
    ISSN: 1432-1440
    Schlagwort(e): Key words Chagas" disease ; Trypanosoma cruzi ; chemotherapy ; sterol biosynthesis inhibitors ; nitrofurans ; nitroimidazoles ; autoimmunity
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Current developments in experimental chemotherapy of Chagas’ disease are reviewed, in particular the demonstration that fourth-generation azole derivatives (inhibitors of sterol C14α demethylase), with particular selectivity against Trypanosoma cruzi and special pharmacokinetic properties, are capable of inducing radical parasitological cures in murine models of both acute and chronic disease. These are the first reports of parasitological cure of this disease in its chronic phase. We also discuss the relevance of etiological treatment in the clinical outcome of patients with chronic Chagas’ disease. Although previous studies have suggested an important autoimmune component in the pathogenesis of this disease, recent results obtained using highly sensitive polymerase chain reaction based detection methods and detailed immunological characterization of the inflammatory process associated with chagasic cardiomyopathy indicate a positive correlation between tissue parasitism and the severity of cardiac pathological findings. Effective antiparasitic treatment can lead to regression of the inflammatory heart lesions and fibrosis in experimental animals and to stop the progression of the disease in humans. Taken together, these findings support the notion that the presence of the parasite is a necessary and sufficient condition for chagasic cardiomyopathy and confirm the importance of specific etiological treatment in the management of chronic chagasic patients.
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  • 83
    ISSN: 1436-2813
    Schlagwort(e): Key Words: lung cancer ; culture ; heterogeneity ; drug screening assay ; subline ; chemotherapy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Materialart: Digitale Medien
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  • 84
    Digitale Medien
    Digitale Medien
    Springer
    Annals of oncology 10 (1999), S. 105-109 
    ISSN: 1569-8041
    Schlagwort(e): advanced pancreatic cancer ; chemotherapy ; clinical benefit
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Two case histories are reported here in which a chemotherapeutic approach improved the clinical conditions of patients with advanced pancreatic cancer. Until recently, chemotherapy was considered ineffective in pancreatic cancer, and most oncologists treated these patients with best-supportive-care only. Enthusiasm for systemic therapy of advanced pancreatic cancer is again growing, spurred by the advent of new drugs and new treatment endpoints such as life quality and symptom palliation. Gemcitabine, the most intensively- investigated new drug in pancreatic cancer, has shown an advantage in both survival and clinical benefit over that of 5-fluorouracil (5- FU). Other new drugs such as taxanes have shown interesting levels of activity, and are deserving of further evaluation. Although these results are far from conclusive and are only partially satisfactory, they represent a significant step forward in the treatment of advanced pancreatic cancer.
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  • 85
    Digitale Medien
    Digitale Medien
    Springer
    Annals of oncology 10 (1999), S. 139-150 
    ISSN: 1569-8041
    Schlagwort(e): apoptosis ; chemotherapy ; clinical trials ; gene therapy ; p53
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Nearly twenty years after the initial discovery of p53, we are now in an ideal position to exploit our vast knowledge of p53 biology in the creation of novel cancer therapies. Disruption of p53 function through mutation, or other means, occurs very frequently in human cancer. Loss of p53 function has been linked with unfavourable prognosis in a large number of tumour types, as indicated by more aggressive tumours, early metastasis and decreased survival rates. Many different avenues of research have converged upon p53 to highlight this protein as being one of the foremost cellular responders to stress, in particular to DNA damage. Huge advances have been made in understanding the complex role p53 plays in the regulation of apoptosis and cell cycle arrest. This review is not meant to be a comprehensive description of p53 biology, but rather serves to highlight current progress in the development of p53- oriented cancer therapies. These may be categorised into three basic strategies: gene replacement therapy using wild-type p53, restoration of p53 function by other means and, finally, targeting of the p53 dysfunction itself. Rapid progress is expected to be made regarding the identification of conventional pharmaceutical agents which either work in a p53-independent manner or act preferentially in p53 defective cells. Gene replacement therapy with wild-type p53 also holds considerable potential for obtaining clinically relevant results quickly. The other forms of cancer therapies based around p53 are much further behind in the developmental process, but may prove to more efficacious in the long run, especially in terms of specificity. As with many other fields, the innovation of successful p53-oriented cancer therapies is only limited by our understanding of p53 biology and the creative use of such knowledge.
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  • 86
    ISSN: 1569-8041
    Schlagwort(e): antiretroviral ; chemotherapy ; granulocyte-colony stimulating factor ; HIV infection ; Hodgkin's disease ; therapy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Background: The optimal therapeutic approach for patients with Hodgkin's disease and human immunodeficiency virus infection (HD–HIV) is unknown. In an attempt to improve the results previously obtained with EBV (epirubicin, bleomycin and vinblastine) without G-CSF (Cancer 1994; 73: 437–44), in January 1993 we started a trial using chemotherapy (CT) consisting of EBV plus prednisone (EBVP), concomitant antiretroviral therapy (zidovudine, AZT or dideoxinosyne, DDI) , and G-CSF. Patients and methods: Up to August, 1997, 35 (30 M/5 F) consecutive previously untreated patients (median age 34, range 21–53 years) with HD–HIV were enrolled in the European Intergroup Study HD–HIV. Their median performance status was 1 (range 1–3). At diagnosis of HD, 26% of the patients had AIDS, 90% had B symptoms at HD presentation and 83% had advanced-stage HD. Patients received E 70 mg/m2 i.v. on day 1, B 10 mg/m2 i.v. on day 1, V 6 mg/m2 i.v. on day 1 and P 40 mg/m2 p.o. from day 1 to day 5 (EBVP). Courses were repeated every 21 days for six cycles. AZT (250 mg × 2/day), or DDI (200 or 300 mg × 2/day) if AZT had been previously used, were given orally from the beginning of CT. G-CSF was given at the dose of 5 mcg/kg/day s.c. from day 6 to day 20 in all cycles. Results: An overall response rate of 91% was observed. There were 74% complete responses (CR) and 17% partial responses (PR). Toxicity was moderate, with grade 3–4 leukopenia and thrombocytopenia in 10 (32%) and three (10%) patients, respectively. The median number of administered cycles was 6 (range 3–6). Twenty-three of 35 patients received AZT and nine patients received DDI. Three (8%) patients had opportunistic infections (OI) during or immediately after CT. The median CD4+ cell count was 219/mm3 (6–812) at HD diagnosis and 220/mm3 (2–619) after the end of combined therapy, and these numbers remained unchanged. Ten of 26 (38%) patients who achieved CR relapsed. Twenty-three patients died of HD progression alone or in association with OI, being the cause of death in 48% and 9% of patients respectively. The median survival was 16 months, with a survival rate of 32% and a disease-free survival of 53% at 36 months. Conclusions: The combined antineoplastic and antiretroviral treatment is feasible, but HD in HIV setting is associated with a more adverse prognosis than in the general population. Although the CR rate obtained was satisfactory, the relapse rate was high. Furthermore, comparison of the results of our two consecutive prospective studies demonstrated no overall improvement in the current trial with respect to the CR rate and survival.
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  • 87
    Digitale Medien
    Digitale Medien
    Springer
    Annals of oncology 10 (1999), S. 1043-1049 
    ISSN: 1569-8041
    Schlagwort(e): chemotherapy ; non-small cell lung cancer ; NSCLC ; three-drugs combination
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Background: Paclitaxel, gemcitabine, and cisplatin are each active in non-small-cell lung cancer (NSCLC), and with different modes of action. Hence, a phase II study combining these drugs were conducted. Patients and methods: Treatment was paclitaxel 110 mg/m2 and cisplatin 60 mg/m2 day 1 and 15, with gemcitabine 800 mg/m2 day 1, 8, and 15, every four weeks. Patients had previously untreated NSCLC, measurable disease, age 18–70 years, performance status ≤2, and no brain metastases. Results: Among 49 patients, 6 (group 1) received chemotherapy as described above, while 43 patients (group 2) did not receive gemcitabine day 8. In group 1, all experienced grade 4 neutropenia and four achieved a partial response (67%). In group 2, neutropenia grade 4 occured in 58%, with one episode of febrile neutropenia and no toxic death. No other grade 4 toxicities occured, while grade 3 toxicity occured with respect to thrombocytopenia (9%), nausea/vomiting (12%), neurotoxicity (12%), and nephrotoxicity (7%). There were 3 complete and 20 partial responses (response rate 54%, 95% confidence limits 38%–69%), median response duration 29 weeks (range 10–66+), median time to progression 28 weeks (range 4–66+), median survival 46 weeks (4–89+) and one-year survival rate 42%. Conclusion: This regimen of paclitaxel, gemcitabine, and cisplatin has neutropenia as dose limiting toxicity, but septicemic episodes were rare and toxic death did not occur. Other grade 4 toxicities than neutropenia did not occur. The regimen appears safe and with a noteworthy activity both in terms of response rate, time to progression, and survival.
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  • 88
    ISSN: 1569-8041
    Schlagwort(e): chemotherapy ; non-metastatic osteosarcoma ; prognosis
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract This study evaluates histological response, long-term outcome, and toxicity in an intensive chemotherapy program given before surgery. Patients and methods: Sixty-two patients (39 males, 23 females; median age 14) with biopsy, chest computerised-tomography, technetium bone-scan and magnetic resonance imaging, were enrolled. Primary localisations were femur (44%) and tibia (26%). Induction chemotherapy involved seven courses of high-dose methotrexate and two courses of HELP (ifosfamide, eldesine (vindesine), cisplatin (platinum)–doxorubicin. After surgery, patients received six courses of high-dose methotrexate and two courses of HELP–doxorubicin. Results: Pre- and postoperative toxicities were similar. Fifty-nine patients underwent surgery: histological response was good in thirty-eight patients (64%) and poor in twenty-one (36%). Median follow-up is 57 months (range 30–80), with 77% overall survival and 59% progression-free survival. In a multivariate analysis, age under 10 years is the only prognostic factor that significantly correlates with outcome. Conclusions: This regimen appears to increase histological necrosis, but associates with severe toxicity. Results for patients with less necrosis at surgery are encouraging. Future trials should determine the minimum effective doses to reduce toxicity. New drugs should be added.
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  • 89
    Digitale Medien
    Digitale Medien
    Springer
    Annals of oncology 10 (1999), S. 17-20 
    ISSN: 1569-8041
    Schlagwort(e): advanced ovarian cancer ; chemotherapy ; duration ; treatment
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Documentation for the optimal duration of first-line chemotherapy in advanced ovarian cancer is limited. Three randomised trials have compared 5-6 cycles with 8, 10 and 12 cycles respectively. None of the studies showed benefit of chemotherapy beyond 6 cycles. At the moment the standard number of cycles therefore must be 6 cycles. However, these data are based on platinum poly-chemotherapy regimens without taxanes. It may be that the optimal number of cycles is different when using taxanes regimens. It is not possible to tell from the literature if there is a relationship between the number of cycles and response or between the cumulative dose and response. At the moment no trial has shown any benefit of high-dose intensity chemotherapy administered over a short time compared with standard dose chemotherapy administered over a longer period.
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  • 90
    ISSN: 1569-8041
    Schlagwort(e): cervical cancer ; chemotherapy ; cisplatin ; ifosfamide ; paclitaxel ; survival
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Purpose: The results of salvage chemotherapy for recurrent or persistent squamous-cell cervical cancer are unsatisfactory. Cisplatin and Ifosfamide are effective compounds in cervical cancer. Paclitaxel has recently been tested with promising results. The aim of this study was to assess the efficacy of a combination of paclitaxel, ifosfamide and cisplatin (TIP) for persistent/recurrent squamous-cell cervical carcinoma in a phase II trial. Patients and methods: Forty-five women were treated with the TIP regimen. Thirty-one had received prior irradiation. Paclitaxel was given at a dose of 175 mg/m2, ifosfamide at a dose of 5 g/m2, and cisplatin at a dose of 75 mg/m2 (50 mg/m2 in irradiated patients) at three-week intervals. Results: We observed 15 clinical complete responses, 15 partial responses, 9 stable diseases and 6 progressions. The objective response rate was 67% (95% confidence interval: 51%–81%). Ten complete responders underwent subsequent surgery and seven had pathology-defined complete responses (two in irradiated areas). The response rate was 52% in irradiated and 75% in non-irradiated areas. The median survival for non-responders is 6 months, 9+ month for partial responders and 13+ for complete responders. The most relevant side effect was myelotoxicity, with 91% of patients experiencing grade 3–4. One woman had life-threatening toxic effects. Conclusions: This combination is highly effective for salvage treatment in non-irradiated patients. For irradiated women the response rate is higher than that observed with other regimens but further investigation is warranted. The toxicity is relevant but adequate hydration and prolonged infusion of ifosfamide make it acceptable.
    Materialart: Digitale Medien
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  • 91
    Digitale Medien
    Digitale Medien
    Springer
    Annals of oncology 10 (1999), S. 185-187 
    ISSN: 1569-8041
    Schlagwort(e): chemotherapy ; endocrine tumours ; immunotherapy ; interferon
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract The various pancreatic endocrine tumors (PETs) share histological features with each other and with the carcinoid. The aspects of chemotherapy and/or interferon concern the management of metastatic disease. The value of chemotherapy is difficult to evaluate from the literature because often no distinction is made between the various types of PETs and carcinoids are often also included. Moreover, it has been shown that not each tumor responds equally to chemotherapy, depending on a functioning or non-functioning state of the tumor. In general the response rate to any cytostatic drug, single agents or combinations, is low.
    Materialart: Digitale Medien
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  • 92
    Digitale Medien
    Digitale Medien
    Springer
    Annals of oncology 10 (1999), S. 305-307 
    ISSN: 1569-8041
    Schlagwort(e): biliay tract cancer ; chemotherapy ; 5-fluorouracil ; gemcitabine ; intra-arterial chemotherapy ; pancreatic cancer ; regional chemotherapy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Chemotherapy of carcinomas of the pancreas and biliary tract has always been of limited value. Pancreatic cancer is well known for its aggressive nature, poor prognosis and resistance to antineoplastic agents which are effective in other solid tumors. 5-Fluorouracil has long been the mainstay of the treatment of pancreatic cancer, although the response rate to this agent is 〈10% and the influence on survival and quality of life is neglegible. Combination chemotherapy in pancreatic cancer adds to the side effects of treatment, but has had no proven effect on effectiveness. The only new anticancer drug of which an improvement in clinical benefit has been indicated on the basis of randomized clinical research, is gemcitabine, although the magnitude of improvement is limited. Due to the rarity of tumors of the biliary tract, the data on the effect of chemotherapy in this disease is sparse but does not suggest that it leads to superior results than supportive care alone. Likewise, no literature exists supporting the routine application of regional chemotherapy infusion in these type of tumors.
    Materialart: Digitale Medien
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  • 93
    Digitale Medien
    Digitale Medien
    Springer
    Annals of oncology 10 (1999), S. 139-146 
    ISSN: 1569-8041
    Schlagwort(e): anthracycline ; breast cancer ; chemotherapy ; HER-2 antibody ; N,N-diethyl-2[4-(phenylmethyl)-phenoxy] ethanamine.HCl (DPPE, BMS-217380-01) ; paclitaxel
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Anthracyclines and taxanes are the two most active classes of chemotherapy for the treatment of advanced breast cancer. Recent studies have investigated combination therapy including doxorubicin (Dox) and paclitaxel. The efficacy of this combination has been established in a phase III study conducted by ECOG, comparing Dox/paclitaxel versus Dox versus paclitaxel. The combination is superior to Dox or paclitaxel with respect to response rate and time to disease progression, indicating that the combination provides a new standard for the first line treatment of metastatic breast cancer [1]. Phase II studies using higher doses of Dox and using shorter infusions of paclitaxel have suggested the combination can be further optimised; Gianni reported a 94% objective response rate using Dox 60 mg/m2 followed by paclitaxel 175 mg/m2 given over three hours [2]. The more active regimens are associated with enhanced cardiotoxicity; this toxicity can be avoided, however, by limiting the exposure to doxorubicin. The newer regimens have now been moved into phase III studies. Future progress for this disease will depend on the introduction of new agents. Two novel drugs are currently being investigated in randomised phase III trials as potentiators of Dox and/or paclitaxel. One is a monoclonal antibody from Genentech (Herceptin, trastuzumab) directed at the HER-2/neu oncogene, which is overexpressed in 〉25% of breast cancers [3]. Recent results indicate that Herceptin in combination with paclitaxel (or with a Dox plus cyclophosphamide regimen) induces a higher response rate (RR) and prolongs the time to disease progression when compared to chemotherapy alone. The second agent N,N-diethyl-2[4-(phenylmethyl)-phenoxyl] ethanamine.HCl (DPPE, BMS-217380-01), when combined with Dox, was associated with a higher RR than previously observed with Dox alone [4]. A randomised trial of Dox versus Dox plus DPPE is ongoing. The possible mechanisms underlying chemo-potentiation by these agents are discussed. As new anthracycline/taxane combinations establish themselves in earlier stages of the disease, the need for effective, non-cross resistant salvage regimens will emerge.
    Materialart: Digitale Medien
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  • 94
    Digitale Medien
    Digitale Medien
    Springer
    Annals of oncology 10 (1999), S. 1475-1483 
    ISSN: 1569-8041
    Schlagwort(e): chemotherapy ; cisplatin ; long-term toxicity ; testicular cancer
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Background: The prognosis of advanced testicular cancer has improved considerably after the introduction of cisplatin-based combination chemotherapy. The improved prognosis of testicular cancer has brought the long-term toxicity of the treatment into focus. Patients and methods: Long-term toxicity was investigated prospectively intil more than 10 years after after treatment in a group of 22 patients treated with six series of cisplatin based chemotherapy (PVB) for testicular cancer. We have focused on nephro-, neuro-, pulmonary-, and gonadal toxicity. Results: Glomerular filtration rate (GFR) decreased significantly during treatment but increased during follow-up and all the patients had normal values of GFR 10–15 years after treatment. Carbon monoxide diffusion capacity (TLco) decreased during PVB treatment in smokers. TLco remained unchanged during the first years after PVB treatment, but improvement of TLco was seen in some patients more than 43 months after treatment. Paresthesia was reported by 83% of the patients immidiately after treatment, 50% at follow-up 4–9 years after chemotherapy and 14% prevalence 11–15 hears after treatment. The reported decline in neurotoxicity was verified by normalisation of vibration perception. Gonadal toxicity was severe and persistent although improvement was seen in a few patients even many years after treatment. Conclusions: The patients treated with PVB were physically and socially well-being at follow-up investigation 11–15 years after treatment. Improvements in pulmonary- and renal function, and recovery from neurotoxicity was seen during the long-term follow-up periode. Gonadal toxicity was severe and persistent.
    Materialart: Digitale Medien
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  • 95
    Digitale Medien
    Digitale Medien
    Springer
    Annals of oncology 10 (1999), S. 157-161 
    ISSN: 1569-8041
    Schlagwort(e): chemotherapy ; 5-fluorouracil ; gemcitabine ; pancreatic cancer ; pancreaticobiliary cancer
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract At time of presentation the majority of patients with pancreaticobiliary cancer have locally advanced or metastatic disease which makes them unamenable for curative surgery. In these patients chemotherapy is an option which has gained more support over the past few years. Special problems faced in chemotherapeutic treatment are the patient's poor condition and the difficulties faced in evaluating response. 5-FU has been the only drug with some efficacy for a long time, but more recently gemcitabine appeared to be more efficient. In locally advanced pancreatic cancer the combination of chemotherapy with radiotherapy has not gained much support. However, studies are implicating better local control with combined treatment and recurrences appear more often at distant sides. In some cases irresectable tumors became resectable. Because of the poor survival after surgery with curative intent, adjuvant and neoadjuvant therapy are becoming important issues. Although studies of adjuvant therapy suggest benefit, research is seriously hampered by poor patient accrual due to the morbidity of pancreaticoduodenectomy. Neoadjuvant treatment may overcome this problem. Until now there has been only modest improvement in the treatment of pancreatic cancer. Hopefully, new treatment modalities such as immunotherapy, gene therapy and antiangiogenic therapy will alter this dismal picture. In biliary cancer the role of chemotherapy is less well defined, since only few studies with low patients numbers have been performed.
    Materialart: Digitale Medien
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  • 96
    Digitale Medien
    Digitale Medien
    Springer
    Annals of oncology 10 (1999), S. 234-238 
    ISSN: 1569-8041
    Schlagwort(e): chemotherapy ; 5-fluorouracil ; gemcitabine ; pancreatic carcinoma
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract The current role of chemotherapy in pancreatic cancer is limited. Chemotherapy usually consists of 5-fluorouracil (5FU) and gemcitabine either as a single agent or in combinations. However, response rates are below 15% with minor effects on overall survival. Due to the aggressive behavior of the disease, current emphasis of new experimental chemotherapy is also focusing on clinical benefit: improvement of pain, performance status or weight. The results with gemcitabine indicated that evaluation of new chemotherapeutic agents in pancreatic cancer should not be limited to the evaluation of response rates; single agent gemcitabine not only showed higher response rates than 5FU, but also resulted in clinical benefit for the patients. Several new agents have been introduced into the clinic for treatment of various gastro-intestinal malignancies, whereas novel agents with different types of targets, such as marimastat deserve further attention. Several oral formulations of 5FU, such as capecitabine, UFT, and eniluracil with 5FU, aim to simulate long-term continuous infusion. Response rates of these formulations are comparable to those of 5FU continuous infusion and 5FU bolus injections. However, the convenience of oral administration with reliable plasma drug concentrations makes these agents very attractive as a replacement of traditional 5FU administration. Since 5FU acts by inhibition of thymidylate synthase (TS), resulting in inhibition of DNA synthesis, several new antifolates, directed towards TS, have been developed. However, these agents, such as ZD1694 (Tomudex, Raltitrexed) and LY231514 (MTA, multitargetted antifolate) showed only limited efficacy. Other new agents active in colorectal cancer, e.g. the topoisomerase I inhibitors topotecan and CPT-11, showed only minor activity. The same was observed for the taxanes. Combinations of gemcitabine (cisplatin, 5FU, epirubicin, marimastat) show promising activities, not only regarding response but also with respect to clinical benefit. The effects were better than that for each agent separately. Thus, despite limited activity of single agents, novel combinations especially with gemcitabine are promising, with emphasis on improvement of the clinical benefit of patients.
    Materialart: Digitale Medien
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  • 97
    Digitale Medien
    Digitale Medien
    Springer
    Annals of oncology 10 (1999), S. 77-82 
    ISSN: 1569-8041
    Schlagwort(e): chemotherapy ; non-small cell lung cancer
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Until recently the role of chemotherapy in NSCLC has generally been questioned. Major concerns included marginal activity, considerable toxicity and high cost of this treatment. There has, however, been increasing evidence from individual studies and meta-analyses that chemotherapy in advanced NSCLC is able to increase survival and improve quality of life. In the past few years a series of active drugs (paclitaxel, docetaxel, gemcitabine, vinorelbine, topotecan and irinotecan) with novel mechanisms of action and favourable toxicity profiles have been developed. These agents appear to hold the promise of added therapeutic benefit. In consequence, chemotherapy has currently been considered an important part of the standard treatment in selected patients with advanced NSCLC. Despite recent developments, treatment outcomes in advanced NSCLC remain far from satisfactory, and new effective means are desperately needed if more patients are to enjoy the prospects of long-term survival.
    Materialart: Digitale Medien
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  • 98
    ISSN: 1569-8041
    Schlagwort(e): chemotherapy ; osteosarcoma ; relative dose intensity ; survival ; tumour response
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Background: Despite advances in the treatment of primary limb osteosarcoma, the outcome of patients with primary metastatic and axial skeletal disease remains poor. The European Osteosarcoma Intergroup have assessed a combination chemotherapy regimen consisting of ifosfamide (IFOS) 3 g/m2/d1–2, doxorubicin (DOX) 25 mg/m2/d1–3 i.v. bolus and cisplatin (CDDP) 100 mg/m2/d1. Patients and methods: One hundred nine previously untreated patients with primary osteosarcoma were registered. Eligibility was confirmed in 103. At presentation, 45 eligible patients had metastatic disease, 15 axial skeletal primary tumours and 43 non-metastatic limb tumours. Results: The major toxicities were myelosuppression (90%, grade 3 or 4) and nausea and vomiting (74%, grade 3 or 4). Overall mean relative dose intensity (RDI) was 80% (88% CDDP, 75% IFOS, 81% DOX). Clinical response as measured by reduction in tumour volume occurred in 36% (95% confidence interval (95% CI): 27%–47%) of primary tumours. Response of pulmonary metastases to chemotherapy was seen in 33% (95% CI: 19%–49%). Good histological response (≥90% necrosis of the tumour) occurred in 33% (95% CI: 22%–45%) of resected tumours. Five-year survival was 62% in limb-non-metastatic, 41% in axial skeletal and 16% in limb metastatic patients. Conclusions: This regimen is active in osteosarcoma but does not appear to be more active than the two-drug CDDP–DOX regimen currently recommended by EOI.
    Materialart: Digitale Medien
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  • 99
    ISSN: 1569-8041
    Schlagwort(e): chemotherapy ; drugs ; generics ; prioritization
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract The WHO has previously produced recommendations on the essential drugs required for cancer therapy. Over the last five years several new anti cancer drugs have been aggressively marketed. Most of these are costly and produce only limited benefits. We have divided currently available anti-cancer drugs into three priority groups. Curable cancers and those cancers where the cost-benefit ratio clearly favours drug treatment can be managed appropriately with regimens based on only 17 drugs. All of these are available, at relatively low cost, as generic preparations. The wide availability of these drugs should be the first priority. The second group of drugs may have some advantages in certain clinical situations. Based on current evidence, drugs in the third group are judged as currently not essential for the effective delivery of cancer care. Adequate supportive care programmes with the widespread availability of effective drugs for pain control are of considerably greater importance. The adoption of these priorities will help to optimise the effectiveness and efficiency of chemotherapy and ensure equitable access to essential drugs especially in low resource environments. Clearly this paper represents the views of its contributors. The WHO welcomes feedback from all oncologists so that the advice it gives to governments in prioritising the procurement of anti cancer drugs can be as comprehensive as possible.
    Materialart: Digitale Medien
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  • 100
    ISSN: 1569-8041
    Schlagwort(e): chemotherapy ; hematopoietic growth-factor support ; high-dose chemotherapy ; peripheral blood stem-cell transplantation ; small-cell lung cancer ; treatment toxicity and mortality
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Background: We conducted a phase I–II trial to assess the feasibility and activity of a combination chemotherapy regimen with etoposide, ifosfamide, cisplatin or carboplatin, and epirubicin in limited-disease (LD, stages I–IIIB) and extensive-stage (ED, stage IV) small-cell lung cancer (SCLC). Patients and methods: Standard-dose chemotherapy (SDC) consisting of etoposide (500 mg/m2), ifosfamide (4000 mg/m2), cisplatin (50 mg/m2) and epirubicin (50 mg/m2) (VIP-E), followed by granulocyte colony-stimulating factor (G-CSF), was given to 100 patients with SCLC. Thirty patients with qualifying responses to VIP-E proceeded to high-dose chemotherapy (HDC) with autologous peripheral blood stem-cell transplantation (PBSCT) after etoposide (1,500 mg/m2), ifosfamide (12,000 mg/m2), carboplatin (750 mg/m2) and epirubicin (150 mg/m2) (VIC-E) conditioning. Results of standard-dose VIP-E: Ninety-seven patients were evaluable for response. The objective response rate was 81% in LD SCLC (33% CR, 48% PR; excluding patients in surgical CR) and 77% in ED SCLC (18% CR, 58% PR). The treatment-related mortality (TRM) of SDC was 2%. Two additional patients in CR from their SCLC developed secondary non-small-cell lung cancers (NSCLC), and both were cured by surgery. The median survival was 19 months in LD SCLC and 6 months in ED SCLC. The five-year survivals were 36% in LD and 0% in ED SCLC. Results of high-dose VIC-E: HDC was feasible in 16% of ED-, and 58% of LD-patients. All HDC patients (n = 30) improved or maintained prior responses. Four patients died of early treatment-related complications (TRM 13%). Two additional patients in CR from their SCLC developed secondary malignancies (esophageal cancer, secondary chronic myelogenous leukemia). The median survivals were 26 months in LD SCLC, and 8 months in ED SCLC. The five-year survival was 50% in LD and 0% in ED SCLC. Conclusions: Despite high response rates, survival after VIP-E SDC and VIC-E HDC in patients with ED SCLC is not superior to that achieved with less toxic traditional regimens. The high five-year survival rates achieved with these protocols in LD SCLC probably reflect both patient selection (high proportion of patients with prior surgical resection) and the high activity of our chemotherapy regimen in combination with radiotherapy. A study comparing protocols using simultaneous radiation therapy and chemotherapy, and other dose-escalated forms of SDC with HDC is needed to further define the role of this treatment modality in SCLC. Given the high rate of secondary malignancies observed in patients in CR 〉2 years in our study, close follow-up and early treatment of these neoplasms may contribute to maintaining overall survival in patients with SCLC.
    Materialart: Digitale Medien
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