240 research outputs found
Stationary Points of O'Hara's Knot Energies
In this article we study the regularity of stationary points of the knot
energies introduced by O'Hara in the range . In a
first step we prove that is on the set of all regular embedded
closed curves belonging to and calculate its derivative.
After that we use the structure of the Euler-Lagrange equation to study the
regularity of stationary points of plus a positive multiple of the
length. We show that stationary points of finite energy are of class
- so especially all local minimizers of among curves with fixed
length are smooth.Comment: Corrected typo
Transforming Growth Factor Alpha Stimulation of Mucosal Tissue Cultures from Head and Neck Squamous Cell Carcinoma Patients Increases Chemoresistance to Cisplatin
The monoclonal epidermal growth factor receptor ( EGFR) antibody cetuximab (Erbitux(TM)) was recently approved by the European Medicines Agency for the treatment of recurrent and/or metastatic head and neck squamous cell carcinoma (HNSCC) in combination with a platinum-based chemotherapy. Since the antibody has only a limited effect as a monotherapy, possible explanations for the synergistic effect with cisplatin are enhanced antibody-dependent cytoxicity and increased sensitivity to the drug. Most of our knowledge of EGFR biology in HNSCC is based on studies using EGFR inhibitors and/or antibodies. Our study was designed to evaluate the impact of EGFR stimulation on cisplatin-induced DNA damage. Therefore, tissue cultures were produced of tumor-free oropharyngeal mucosa biopsies of HNSCC patients and controls. In a previous study, overexpression of EGFR in tissue cultures from tumor patients compared to controls was confirmed by immunohistochemical staining. Twenty-four-hour stimulation of tissue cultures with transforming growth factor alpha (TGF-alpha), a specific EGFR ligand, resulted in a reduction of cisplatin-induced DNA damage by 35% in cases, whereas in controls TGF-alpha had no effect. This reflects a statistically significant increase in cellular chemoresistance to cisplatin following TGF-alpha stimulation and helps to further understand effects of EGFR antisense therapy in combination with chemotherapy. Copyright (C) 2010 S. Karger AG, Base
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