ABSTRACT
Gliomas are the most common type among all central nervous system tumors. The aggressiveness of gliomas is correlated with the level of angiogenesis and is often associated with prognosis. The aim of this study is to evaluate the novel GX1 peptide and the heterodimer RGD-GX1 radiolabeled with technetium-99m, for angiogenesis detection in glioma models. Radiolabeling and radiochemical controls were assessed for both radioconjugates. In vitro binding studies in glioma tumor cells were performed, as well as biodistribution in SCID mice bearing tumor cells, in order to evaluate the biological behavior and tumor uptake of the radiocomplexes. Blocking and imaging studies were also conducted. MicroSPECT/CT images were acquired in animals with experimentally implanted intracranial tumor. Open field activity was performed to evaluate behavior, as well as perfusion and histology analysis. The radiochemical purity of both radiotracers was greater than 96 %. In vitro binding studies revealed rather similar binding profi le for each molecule. The highest binding was for RGD-GX1 peptide at 120 min in U87MG cells (1.14 +/- A 0.35 %). Tumor uptake was also favorable for RGD-GX1 peptide in U87MG cells, reaching 2.96 +/- A 0.70 % at 1 h p.i. with 47 % of blocking. Imaging studies also indicated better visualization for RGD-GX1 peptide in U87MG cells. Behavior evaluation pointed brain damage and histology studies confirmed actual tumor in the uptake site. The results with the angiogenesis seeking molecule Tc-99m-HYNIC-E-[c(RGDfk)-c(GX1)] were successful, and better than with Tc-99m-HYNIC-PEG(4)-c(GX1). Future studies targeting angiogenesis in other glioma and nonglioma tumor models are recommended.
Subject(s)
Biochemistry , Medical Oncology , Molecular BiologyABSTRACT
The alignment properties of lyotropic nematic liquid crystals (LNLC) on treated substrates were studied. Hydrophobic vs hydrophilic surfaces as well as rubbed vs nonrubbed surfaces were used to investigate the influence of the boundary surfaces on the spontaneous alignment of LNLC. It was found that the nematic particles can follow the anchoring direction imposed by the surface only when the LNLC material is strongly confined. We also observed a phase transition induced by surface action in the case of strong confinement. The reorientation and relaxation processes of the nematic director at the treated boundary surfaces were also studied. The characteristic times of these processes were found to be dependent on the sample thickness and the surface properties.
