Publications by authors named "Michael Assmann"

Introduction: The combination of Imatinib (IM) and hydroxyurea (HU) was explored for the treatment of chronic myelogenous leukemia (CML).

Method: After testing and a phase I study ( = 20), 59 patients were randomized in the IM/HU and 29 in the IM arm. According to protocol, 49 propensity-score matched IM patients were included from the CML-IV study.

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Rationale: There is a paucity of data on the incidence of neuroendocrine tumors (NET) outside pulmonary primaries and on treatment modalities applied to patients with NET in clinical practice. Only very little therapeutic progress has been made with respect to response and overall survival, particularly among patients with poorly differentiated, WHO grade 3 neuroendocrine carcinomas (G3-NEC). We sought to document the incidence and treatment modalities in patients with NET/NEC within a period of 2 years.

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Introduction: Bortezomib (Velcade) is a proteasome inhibitor that has shown important clinical efficacy either as a single agent or in combination with other cytostatic agents in multiple myeloma (MM). In the present protocol, bortezomib was combined with other active substances like bendamustine and prednisone (BPV), in order to assess the efficacy and toxicity of the combination therapy in patients with relapsed or refractory MM.

Methods: Between January 2005 and December 2011, 78 patients with relapsed or refractory MM were treated with bendamustine 60 (-120) mg/m(2) on days 1 and 2, bortezomib 1.

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This study of first-line treatment in advanced-stage follicular lymphoma patients analysed the effects of MCP (mitoxantrone, chlorambucil and prednisolone) chemotherapy alone or in combination with rituximab (R-MCP) on circulating lymphoma cells (CLC) and assessed the prognostic value of a quantitative monitoring of CLC. CLC numbers were determined by quantitative polymerase chain reaction (PCR) for the t(14;18)-translocation or by allele-specific PCR for rearranged immunoglobulin heavy chain genes. We analysed blood samples from 43 patients treated in a randomized trial comparing eight cycles of MCP versus R-MCP.

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Purpose: Rituximab has been shown to be active in follicular lymphoma (FL), both as monotherapy and in combination with chemotherapy. We conducted a randomized trial comparing mitoxantrone, chlorambucil, and prednisolone (MCP) chemotherapy plus rituximab with MCP alone.

Patients And Methods: Previously untreated patients with stage III or IV CD20+ indolent or mantle cell lymphoma were randomly assigned to either eight 28-day cycles of MCP plus rituximab (R-MCP; n = 181) or eight cycles of MCP alone (n = 177).

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The chemistry of the burrowing sponge Aka coralliphagum was investigated to identify chemically labile secondary metabolites. The HPLC-MS analysis of the two growth forms typica and incrustans revealed different metabolites. The previously unknown sulfated compounds siphonodictyals B1 to B3 (6-8), corallidictyals C (9) and D (10), and siphonodictyal G (11) were isolated, and their structures were elucidated by NMR and MS experiments.

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Bromophenols are present in polychaetes as well as in algae in marine environments including the North Sea. They are thought to cause the typical sea-like taste and flavour. The ecological function of brominated phenols is not clear yet, but they may play a role in chemical defence and deterrence [Kicklighter, C.

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A secondary metabolite from sponges of the genus Agelas, 4,5-dibromopyrrole-2-carboxylic acid, which is well known as feeding deterrent, was investigated for effects on the cellular calcium homeostasis in PC12 cells. 4,5-Dibromopyrrole-2-carboxylic acid did not change intracellular calcium levels if applied alone without cell depolarization. During depolarization of the cellular membrane using high potassium solution, a dose dependent reduction of intracellular calcium elevation was revealed utilizing Fura II as calcium indicator.

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Seven pyrrole alkaloids isolated from Agelas sponges were tested for interactions with the cellular calcium homeostasis. Brominated pyrrole alkaloids reduced voltage dependent calcium elevation in PC12 cells. Dibromosceptrin was the most potent alkaloid with a half maximal concentration of 2.

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The therapy of patients with relapsed or refractory indolent lymphoma relies on the development of new drug combinations. The drugs bendamustine and fludarabine have cytotoxic activity as monotherapy in indolent lymphoma and show synergism in vitro. In this study, we combined both drugs in a multicenter clinical phase I/II trial to evaluate their toxicity and efficacy.

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Six dimeric bromopyrrole alkaloids (1-6) were isolated from a Florida Keys specimen of Agelas conifera. One of the constituents was identified as a new bromopyrrole metabolite, bromosceptrin (1). The structure of 1 was established from MS spectrometry and 1D and 2D NMR spectrocopy.

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A detailed analysis of the chemical constituents of a Caribbean specimen of Agelas sp. was carried out. Four brominated compounds (1-4) were isolated and one of them was identified as a new bromopyrrole metabolite, monobromoisophakellin (1).

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