sepharose and Skin-Neoplasms

Radiation therapy is a common treatment modality employed in the treatment of cancer. High energy photons are the primary source of radiation but when administered, they leave an exit dose resulting in radiation damage to the adjacent healthy tissues. To overcome this, high energy electrons are employed in cases of skin cancer to minimize radiation induced toxicity. Despite these advances, measurement of delivered radiation remains a challenge due to limitations with existing dosimeters including labor intensive fabrication, complex read-out techniques and post-irradiation instability. To overcome these limitations, we have developed a novel colorimetric plasmonic gel nanocomposite for the detection of therapeutic levels of radiation delivered in electron beam therapy. The plasmonic nanocomposite consists of an agarose gel matrix encapsulating precursor gold ions, which are reduced to gold nanoparticles as a result of exposure to high energy electrons. The formation of gold nanoparticles renders a change in color to the agarose matrix, resulting in the formation of plasmonic gel nanocomposites. The intensity of the color formed exhibits a linear relation with the delivered electron dose, which can be quantified using absorbance spectroscopy. The plasmonic gel nanocomposites were able to detect doses employed in fractionated electron therapy, including in an anthropomorphic phantom used for planning radiation treatments in the clinic. Furthermore, the use of glutathione as a quenching agent facilitated qualitative and quantitative spatial mapping of the delivered dose. Our results indicate that the ease of fabrication, simplicity of detection and quantification using absorbance spectroscopy, determination of spatial dose profiles, and relatively low cost make the plasmonic gel nanocomposite technology attractive for detecting electron doses in the clinic.

Topics: Colorimetry; Electrons; Gold; Humans; Nanogels; Particle Size; Phantoms, Imaging; Sepharose; Skin Neoplasms; Surface Properties

We developed a method, termed Cell and Tissue Display (CTD), for embedding 16 or more different tissue samples in multi-compartment agarose blocks. The CTD-generated blocks allow uniform multiplexing of cell lines and small tissue fragments within a single histologic block. The distribution of individual cells within the CTD blocks is improved, likely because the individual agarose compartments are small and uniform. The composition of each CTD block can be customized based on intended use. Some potential uses of CTD histologic blocks include improved sectioning of small tissue fragments, such as needle biopsy specimens or punch biopsies; multiplexing of tissue fragments within a single block; and the generation of control slides for laboratory proficiency testing. .

Topics: Animals; Brain; Cell Line, Tumor; Colon; Humans; Melanoma; Mice, Inbred C57BL; Microscopy; Sepharose; Skin; Skin Neoplasms; Tissue Embedding

Cell transplantation after enclosing in microcapsules has been studied as an alternative approach for treatment of wide variety of diseases. In the present study, we examined the feasibility of using agarose microcapsules, having a cell-enclosing hollow core of 100-150 microm in diameter and agarose gel membrane of about 20 microm in thickness, as a device for the methodology. We enclosed cells that had been genetically engineered to express cytochrome P450 2B1, an enzyme that activates the anticancer prodrug ifosfamide. The enclosed cells were shown to express the enzymatic function in the microcapsules in that they suppressed the growth of tumor cells in medium containing ifosfamide. In addition, a more significant regression of preformed tumors was observed in the nude mice implanted with the cell-enclosing microcapsules compared with those implanted with empty capsules after administration of ifosfamide. Preformed tumors shrank by less than 40% in volume in 6 of the 10 recipients implanted with cell-enclosing microcapsules. In contrast, only 1 in 10 of the preformed tumors in the recipient implanted with empty microcapsules shrank by this amount. These results suggest that agarose microcapsules containing cytochrome P450 2B1 enzyme-expressing cells are feasible devices for improving the chemotherapy of tumors. Thus, agarose microcapsule having hollow cores are generally a good candidate as vehicles for cell-encapsulation approaches to cell therapy.

Topics: Animals; Antineoplastic Agents, Alkylating; Capsules; Cell Transplantation; Cell- and Tissue-Based Therapy; Cells, Cultured; Combined Modality Therapy; Cytochrome P-450 CYP2B1; Drug Delivery Systems; Ifosfamide; Male; Mice; Mice, Inbred BALB C; Mice, Nude; Sepharose; Skin Neoplasms; Xenograft Model Antitumor Assays

Angiogenesis, the development of new blood vessels from preexisting vessels, is crucial to tissue growth, repair, and maintenance. This process begins with the formation of endothelial cell sprouts followed by the proliferation and migration of neighboring endothelial cells along the preformed extensions. The initiating event and mechanism of sprouting is not known. We show that the phenotypic expression of negatively charged membrane surface in apoptotic cells initiates the formation of directional endothelial cell sprouts that extend toward the dying cells by a mechanism that involves endothelial cell membrane hyperpolarization and cytoskeleton reorganization but is independent of diffusible molecules.

Topics: Animals; Apoptosis; Cell Communication; Cell Movement; Cells, Cultured; Coculture Techniques; Endothelium, Vascular; ErbB Receptors; Ferritins; Fibroblast Growth Factor 2; Ion Channels; Melanoma; Membrane Potentials; Mice; Neovascularization, Physiologic; Phospholipids; Purines; Rats; Receptors, Vascular Endothelial Growth Factor; Sepharose; Skin Neoplasms; Static Electricity

Vascular TTB cells derive from murine Kaposi's sarcoma-like dermal lesions and share several phenotypic features with AIDS-associated KS spindle cells. We have recently reported that fibroblast growth factor-2 (FGF-2) promotes dramatic cytoskeletal and morphological alterations in TTB cells, concomitant with the induction of an autocrine loop for hepatocyte growth factor and a relocalization of the urokinase receptor. Since all these alterations are hallmarks of cell transformation. we attempted to verify whether FGF-2 induces a transformed phenotype in TTB cells. Our results show that FGF-2-treated TTB cells acquire the ability to grow under anchorage-independent conditions. In addition, FGF-2 markedly reduced the levels of thrombospondin-1, an antiangiogenic and tumor suppressor protein, in TTB cells. Therefore, FGF-2 induces KS-like spindle cells to acquire properties characteristic of transformed cells. This suggests that FGF-2 plays a pathogenetic role in KS not only by promoting angiogenesis, but also by conferring a transformed phenotype upon KS cells. In light of previous reports on Tat-induced release of FGF-2 into the extracellular space, our findings may provide an additional mechanism for the observed synergism between Tat and FGF-2 in the pathogenesis of KS.

Topics: Animals; Autocrine Communication; Cell Division; Cell Line, Transformed; Cell Movement; Cell Transformation, Neoplastic; Fibroblast Growth Factor 2; Gene Products, tat; HIV; Mice; Mice, Transgenic; Phenotype; Sarcoma, Kaposi; Sepharose; Skin Neoplasms; tat Gene Products, Human Immunodeficiency Virus; Thrombospondin 1; Tumor Cells, Cultured; Tumor Stem Cell Assay