A novel transcutaneous CO2 therapy significantly enhanced the antitumor effectiveness of X-ray irradiation in human MFH xenografts The results strongly suggest that transcutaneous CO2 therapy could be a novel therapeutic tool for overcoming radioresistance in human malignancies. Hypoxia contributes to tumor radioresistance. In the presence of oxygen, reactive oxygen species (ROS) play crucial roles in cellular apoptosis to irradiation. We previously showed that a novel transcutaneous application of CO2 can improve hypoxia and that it induces apoptosis and decreases the expression of HIF-1α in sarcoma. Therefore, we hypothesised that a transcutaneous application of CO2 may increase radiosensitivity in sarcoma by improvement of hypoxic condition and increasing ROS production in tumors. The purpose of this study is to examine the effect of transcutaneous application of CO2 on radiosensitivity in human malignant fibrous histiocytoma (MFH) cells.Summary Statement
Introduction
Survivin is a member of the inhibitor of apoptosis family, which may contribute to the progression of human MFH via inhibiting the mitochondrial apoptosis, and may be considered as a potent therapeutic target for the treatment of human MFH. Survivin is a member of the inhibitor of apoptosis (IAP) family, which usually expresses in the embryonic lung and fetal organs in the developmental stages, but is undetectable in normal adult tissues other than thymus, placenta, CD34+ stem cells, and basal colonic epitherial cells. However, several studies reported that survivin is highly expressed in various human malignancies, including sarcomas, and increased expression of survivin is an unfavorable prognostic marker correlating with decreased overall survival in cancer patients. We have previously reported that survivin was strongly expressed in human malignant fibrous histiocyoma (MFH), however, the roles of survivin in human MFH have not been studied. The aim of this study was to evaluate the effect of survivin inhibition on apoptotic activity in human MFH cells.Summary Statement
Introduction
It is well known that blood flow is a critical key component of fracture repair. Previously, we demonstrated that transcutaneous application of CO2 increased blood flow in the human body. To date, there has been no report investigating the effect of the carbonated therapy on fracture repair. We hypothesized that the transcutaneous application of CO2 to fracture site would accelerate fracture repair.Introduction
Hypothesis
The material properties of gamma irradiated Ultra High Molecular Weight (UHMW) polyethylene are known to degrade during exposure to air. Though gamma inert-sterilization has been developed to decrease free radicals, the rate of degeneration of UHMW polyethylene in vivo has not well known. This study aimed to compare the properties of gamma inert-irradiated highly-cross-linked UHMW polyethylene samples after exposure to air and the properties of gamma inert-irradiated highly-crosslinked UHMW polyethylene samples after exposure to liquid. UHMW polyethylene samples were machined from heat-compressed sheet made of medical grade GUR 1050 (Ticona, Kelsterbach, Germany). Samples were rectangular, where the dimensions were 50mm in length, 5 mm in width and 2 mm in thickness. Samples were divided into four groups of 0, 60, 100 and 200 kGy irradiation in N2 gas. These samples were then exposed to air or Ringer’s solution for half a year. Dynamic vis-coelastic measurements and, Fourier Transform Infrared Spectrometry (FTIR) and Electron Spin Resonance (ESR) analyses were performed on samples immediately after inert-irradiation, after half-year-exposure to 25°C air (Air-exposure) and after half-year-exposure to 37°C Ringer’s solution (Liquid-exposure). Dynamic viscoelastic measurements were conducted over a temperature range of −150 to 350°C using a Dynamic Mechanical Spectrometer (Seiko Instruments, Osaka, Japan). FTIR analysis was conducted using a Perkin-Elmer Spectra BX (Norwalk, CT) with 100-μm thick slices. ESR analysis was also conducted using a JES-TE200 (Nippon-Denshi, Akishima, Japan). Although the dynamic viscoelastic performance of 0 kGy irradiated storage sample was not different from that of original sample, the loss tangent value (tanδ, E”/E’) of 60, 100 and 200 kGy irradiated storage samples was different from that of original samples (Fig. 1). The difference of Liquid-exposure was larger than that of Air-exposure. Although a FTIR peak at 1718 cm-1 wave numbers was not observed in 0 kGy irradiated storage sample, obvious peak was observed in 100 and 200 kGy irradiated storage samples (Fig. 2). The peak of Liquid-exposure was larger than that of Air-exposure. The ESR analysis showed free radicals in storage samples. The dynamic viscoelastic performance of 60, 100, 200 kGy irradiated storage sample was different from that of original sample, whereas the performance of 0 kGy irradiated storage sample was not different from that of original sample. The difference of Liquid-exposure was larger than that of Air-exposure. The storage modulus value of 60, 100, 200 kGy irradiated Liquid-exposure decreased and the reason for this was thought to be chain scission by oxidation for half-year exposure to Ringer’s solution. Obvious FTIR peak at 1718 cm-1 wave numbers was observed in 100 and 200 kGy irradiated storage samples. The peak of Liquid-exposure was larger than that of Air-exposure. This indicated that the oxidation of Liquid-exposure quickly progressed during half-year storage and the reason for this was thought to be chain scission by high liquid temperature. The results of the present study suggested that the properties of gamma irradiated UHMW polyethylene quickly degraded in vivo.
