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Headington, United Kingdom

Willingale R.,University of Leicester | Feldman C.,University of Leicester | Michette A.,Kings College London | Button T.,University of Birmingham | And 15 more authors.
X-Ray Optics and Instrumentation | Year: 2010

The UK Smart X-Ray Optics (SXO) programme is developing active/adaptive optics for terrestrial applications. One of the technologies proposed is microstructured optical arrays (MOAs), which focus X-rays using grazing incidence reflection through consecutive aligned arrays of microscopic channels. Although such arrays are similar in concept to polycapillary and microchannel plate optics, they can be bent and adjusted using piezoelectric actuators providing control over the focusing and inherent aberrations. Custom configurations can be designed, using ray tracing and finite element analysis, for applications from sub-keV to several-keV X-rays, and the channels of appropriate aspect ratios can be made using deep silicon etching. An exemplar application will be in the microprobing of biological cells and tissue samples using Ti K radiation (4.5keV) in studies related to radiation-induced cancers. This paper discusses the optical design, modelling, and manufacture of such optics. Copyright © 2010 Richard Willingale et al. Source

Tupper J.,Gray Cancer Institute | Stratford M.R.,Gray Cancer Institute | Stratford M.R.,University of Oxford | Hill S.,Gray Cancer Institute | And 5 more authors.
Cancer Gene Therapy | Year: 2010

Gene-directed enzyme prodrug therapy is a form of targeted cancer therapy, in which an enzyme is used to convert a non-toxic prodrug to a cytotoxin within the tumor. Horseradish peroxidase (HRP) is able to convert the indole prodrugs indole-3-acetic acid (IAA) and the halogenated derivative 5-bromo-IAA (5Br-IAA) to toxic agents able to induce cell kill in vitro. This study characterized HRP-directed gene therapy in vivo. Human nasopharyngeal squamous cell carcinoma cells, FaDu, stably expressing HRP were grown as xenografts in SCID mice. Pharmacokinetic analysis of IAA and 5Br-IAA showed satisfactory drug profiles, and millimolar concentrations could be achieved in tumor tissue at non-toxic doses. HRP-expressing tumors showed a modest growth delay when treated with IAA compared with drug-vehicle controls. Treatment response could not be improved using different drug scheduling or drug vehicle, nor by combining HRP-directed gene therapy with fractionated radiotherapy. © 2010 Nature Publishing Group All rights reserved. Source

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