Extracorporeal high-pressure therapy (EHPT) for malignant melanoma consisting of simultaneous tumor eradication and autologous dermal substitute preparation.

Surgical resection of skin tumors leads to large defects in surrounding normal tissues, which should be reconstructed thereafter using the patient's own tissues taken from the other site. Our challenge is to solve this problem in dermal malignant melanoma (MM) by a novel process, named extracorporeal high pressure therapy (EHPT), in which the tissue containing tumor is resected and pressurized, and the treated tissue is re-transplant back to the same position as a tumor-free autologous dermal substitute. The key points are complete tumor death and preservation of native extra cellular matrix (ECM) by the hydrostatic pressure. We found that high hydrostatic pressure at 200 MPa for 10 min at room temperature is completely cytocidal against MM cells in suspension form, in monolayer form, and even in the solid tumor form. MM tumor-bearing nude mice were established by injected human MM cells intradermally and treated by EHTP. The denaturation of the dermal extra cellular matrices was so mild that the pressurized skin was well engrafted as tumor free autologous dermal tissues, resulting in the complete eradication of the MM without any unnecessary skin reconstruction surgery. This very simple and short pressing treatment was proved to make the tumor tissue to the transplantable and tumor-free autologous dermal substitute, which can be applicable to the other temporally resectable tissues.

An Inverse Problems Approach to MR-EPT Image Reconstruction.

Magnetic Resonance-Electrical Properties Tomography (MR-EPT) is an imaging modality that maps the spatial distribution of the electrical conductivity and permittivity using standard MRI systems. The presence of a body within the scanner alters the RF field, and by mapping these alterations it is possible to recover the electrical properties. The field is time-harmonic, and can be described by the Helmholtz equation. Approximations to this equation have been previously used to estimate conductivity and permittivity in terms of first or second derivatives of RF field data. Using these same approximations, an inverse approach to solving the MR-EPT problem is presented here that leverages a forward model for describing the magnitude and phase of the field within the imaging domain, and a fitting approach for estimating the electrical properties distribution. The advantages of this approach are that 1) differentiation of the measured data is not required, thus reducing noise sensitivity, and 2) different regularization schemes can be adopted, depending on prior knowledge of the distribution of conductivity or permittivity, leading to improved image quality. To demonstrate the developed approach, both Quadratic (QR) and Total Variation (TV) regularization methods were implemented and evaluated through numerical simulation and experimentally acquired data. The proposed inverse approach to MR-EPT reconstruction correctly identifies contrasts and accurately reconstructs the geometry in both simulations and experiments. The TV regularized scheme reconstructs sharp spatial transitions, which are difficult to reconstruct with other, more traditional approaches.

Study on structure of ribosomal RNA by time-resolved luminescence anisotropy analysis.

Evaluation of the folded structure of E.coli 16S-rRNA was performed using 5'-Ru(II) complex labeled oligodeoxyribonucleotide (Ru-probe) as the probe. This probe could evaluate the dynamic manner of the binding site of Ru-probe by using the time-resolved luminescence anisotropy technique. It was found that the rotational manner of Ru-probe in the presence of 16S-rRNA was markedly dependent on the oligonucleotide sequence, indicating that the microenvironments around the Ru-probes were largely different.

Characterization of RNA structure by bis-pyrene-labeled 2'-O-methyloligonucleotides.

Properties of 2'-O-methyloligoribonucleotides containing two consecutive 2'-O-(1-pyrenylmethyl)uridine were investigated as a fluorescent probe to search the single strand regions of RNA. The bis-pyrene-labeled 2'-O-methyloligoribonucleotide (OMUpy2) induced the formation of pyrene dimer upon hybridization with the complementary oligoribonucleotides and showed remarkable appearance of broad structureless fluorescence at 480 nm. Contrarily, when OMUpy2 was hybridized with the complementary oligodeoxyribonucleotides, such enhancement of fluorescence was scarcely observed. When various OMUpy2 were applied to E. coli 5S-rRNA, the fluorescence intensity at 480 nm was varied in a sequence specific manner.

Study on RNA structure by pyrene-labeled 2'-O-methyloligoribonucleotides.

Properties of 2'-O-methyloligoribonucleotides containing 2'-O-(1-pyrenylmethyl)uridine were investigated as the fluorescent probe to search the single strand regions on RNA secondary and tertiary structure. The pyrene-labeled 2'-O-methyloligoribonucleotide (OMUpy) showed remarkable increase of fluorescence intensity to 333-fold at 375 nm when hybridized with the complementary oligoribonucleotide. When OMUpy, complementary to loop or stem regions, was applied to E. coli 5S-rRNA, the fluorescence intensities were increased in a sequence specific manner. The difference of the fluorescence intensities corresponds to the higher-order structure of 5S-rRNA, suggesting that pyrene-labled 2'-O-methyloligoribonucleotide can be applicable to search single strand regions of RNA.