Richard F. Schneider

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Tumor hypoxia, present in many human cancers, can lead to resistance to radiation and chemotherapy, is associated with a more aggressive tumor phenotype and is an independent prognostic factor of clinical outcome. It is therefore important to identify and localize tumor hypoxia in cancer patients. In the current study, serial microPET imaging was used to(More)
UNLABELLED The purpose of this study was to determine, with a rodent tumor model, if microelectrode measurements of unmodulated tumor oxygenation predict for the avidity of hypoxic markers to tumor tissue. METHODS The rapidly growing, anaplastic variant of the Dunning rat prostate carcinoma cell line (R3327-AT) was implanted subcutaneously on the upper(More)
UNLABELLED The cyclam ligand (1,4,8,11-tetraazacyclotetradecane) was condensed with various azomycin-containing synthons to produce chemical compounds that could chelate radioactive metals. It was expected that these radiolabeled markers would become bound selectively to hypoxic cells on the bioreduction of their azomycin substituent. METHODS The markers(More)
UNLABELLED Molecular imaging allows the noninvasive assessment of cancer progression and response to therapy. The aim of this study was to investigate molecular and cellular determinants of 3'-deoxy-3'-(18)F-fluorothymidine ((18)F-FLT) PET and diffusion-weighted (DW) MR imaging in lung carcinoma xenografts. METHODS Four lung cancer cell lines (A549,(More)
Second-generation nuclear medicine markers of tumour hypoxia have been synthesised and screened for hypoxic marking activity in cell cultures and in mouse tumours (EMT-6). Markers of the iodinated azomycin nucleoside class with greater water solubility and faster plasma clearance rates relative to iodoazomycin arabinoside (IAZA) were of particular interest.(More)
PURPOSE In the search for a sensitive, accurate, and noninvasive technique for quantifying human tumor hypoxia, our laboratory has synthesized several potential radiodiagnostic agents. The purpose of this study was to assess and compare the hypoxic marking properties of both radioiodinated and Tc-99m labeled markers in appropriate test systems which can(More)
Tumor cells at low oxygen tension are relatively radioresistant. The hypoxic fraction of individual tumors before, during and after radiotherapy is likely to have prognostic value but its diagnosis still awaits an accurate and acceptable assay. The recent indications that hypoxia can also induce the expression of specific genes and promote a more aggressive(More)
A variety of radioactive agents, injected directly intravenously have demonstrated foci of inflammation by gamma camera imaging, avoiding the in vitro preparation of labeled leukocytes. This study sought to find out if any of these agents mimicked the biodistribution in abscesses and non-target organs of labeled mixed leukocyte suspensions. Eight different(More)
99mTc-hexamethylpropylene amine oxime d,1 diastereoisomer (HM-PAO), developed as a diffusible brain imaging agent, labels leukocyte suspensions in saline with an efficiency of 80% using 1–200 μg quantities. In dogs, the recovery and survival of reinjected cells in the bloodstream resemble those of 111In-oxine labeled cells at least for several hours. Images(More)
Cationic dyes of the cyanine type have been observed to specifically inhibit NAD-linked respiration in rat liver mitochondria, with 50% inhibition occurring at about 0.2 mumol/g of mitochondrial protein. The dyes show no effect on succinate oxidation or coupled phosphorylation in the range which completely inhibits NADH oxidation. This specific inhibition(More)