119 research outputs found

    Usability of detecting delivery errors during treatment of prostate VMAT with a gantry-mounted transmission detector

    Get PDF
    Volumetric‐modulated arc therapy (VMAT) requires highly accurate control of multileaf collimator (MLC) movement, rotation speed of linear accelerator gantry, and monitor units during irradiation. Pretreatment validation and monitoring of these factors during irradiation are necessary for appropriate VMAT treatment. Recently, a gantry mounted transmission detector “Delta4 Discover® (D4D)” was developed to detect errors in delivering doses and dose distribution immediately after treatment. In this study, the performance of D4D was evaluated. Simulation plans, in which the MLC position was displaced by 0.5, 1.0, 1.5, 2.0, 2.5, and 3.0 mm from the clinically used original plans, were created for ten patients who received VMAT treatment for prostate cancer. Dose deviation (DD), distance‐to‐agreement (DTA), and gamma index analysis (GA) for each plan were evaluated by D4D. These results were compared to the results (DD, DTA and GA) measured by Delta4 Phantom + (D4P). We compared the deviations between the planned and measured values of the MLC stop positions A‐side and B‐side in five clinical cases of prostate VMAT during treatment and measured the GA values. For D4D, when the acceptable errors for DD, DTA, and GA were determined to be ≤3%, ≤2 mm, and ≤3%/2 mm, respectively, the minimum detectable errors in the MLC position were 2.0, 1.5, and 1.5 mm based on DD, DTA, and GA respectively. The corresponding minimum detectable MLC position errors were 2.0, 1.0, and 1.5 mm, respectively, for D4P. The deviation between the planned and measured position of MLC stopping point of prostate VMAT during treatment was stable at an average of −0.09 ± 0.05 mm, and all GA values were above 99.86%. In terms of delivering doses and dose distribution of VMAT, error detectability of D4D was comparable to that of D4P. The transmission‐type detector “D4D” is thus suitable for detecting delivery errors during irradiation

    Expression of alpha smooth muscle actin in living donor liver transplant recipients

    Get PDF
    Recently, there have been reports from liver biopsies that showed the progression of liver fibrosis in liver transplant patients after the cessation of immunosuppression. Herein, we focused on activated hepatic stellate cells expressing alpha smooth muscle actin (α-SMA) to understand the correlation between immunosuppressant medication and liver fibrosis. The study enrolled two pediatric patients who underwent living donor liver transplantation and ceased immunosuppressant therapy. The number of α-SMA-positive cells in the specimens obtained by liver biopsy from these two patients showed a three-fold increase compared with the number from four transplanted pediatric patients who were continuing immunosuppressant therapy. In addition, the α-SMA-positive area evaluated using the Win- RooF image processing software program continued to increase over time in three adult transplanted patients with liver fibrosis, and the α-SMA-positive area was increasing even during the pre-fibrotic stage in these adult cases, according to a retrospective review. Therefore, α-SMA could be a useful marker for the detection of early stage fibrosis

    Evaluating Groundwater Flow Effects for Enhancement of Ground-Source Heat Pipes in the Case of the Toyohira River Alluvial Fan, Japan

    No full text
    The purpose of this study was to evaluate the potential enhancement of ground-source heat pipes by groundwater advection at two sites within an alluvial fan of Toyohira River, Sapporo. Two sites were selected: one in the fan toe, for negligible groundwater flow (Site 1), and the other in the apex for fast flows, the latter characterized by a specific discharge of 1.0 m/d from the losing river (Site 2). The evaporator section(s) of a single (double) heat pipe(s) was installed in a borehole at each site; the condenser section(s) on the ground was placed inside cooled brine at a set temperature, resulting in heat extraction under steady conditions. The single heat pipe experiments showed that the heat extraction rates ranged between 0.23 and 0.79 kW and were not clearly different at the two sites, considering some uncertainty. For double heat pipes, the heat extraction rates were unchanged at Site 1, but were about 146% higher at Site 2 compared to the single tests, due to groundwater advection. This study revealed that the number of ground-source heat pipes required could be reduced from three to two in areas near Site 2

    Effects of bistheonellide A, an Actin-polymerization Inhibitor, on Chinese Hamster V79 Cells and on IL-8 Production in PMA-stimulated HL-60 Cells

    No full text
    Bioassay-guided isolation from the ethanol extract of a marine sponge Theonella sp. collected in Palau yielded bistheonellide A, which strongly inhibited the colony formation of Chinese hamster V79 cells (EC50 = 6.8 nM). Bistheonellide A is an actinpolymerization inhibitor and was suggested to control cytokine production. Therefore, we attempted to detect an effect of this compound on IL-8 production in PMA-stimulated HL- 60 cells. Interestingly, bistheonellide A did not modulate the production of IL-8 under cytotoxic concentrations as determined by LDH analysis. Although the correlation between the inhibition of microtubule assembly and the stimulation of IL-8 production has been observed for several compounds, the polymerization of actin was not related to an IL-8 production in the case of bistheonellide A. It will be suggested that the actin polymerization is not involved in the IL-8 production system

    A Sesquiterpene Quinone, 5-Epi-smenospongine, Promotes TNF-α Production in LPS-stimulated RAW 264.7 Cells

    No full text
    Eight sesquiterpene quinones: ilimaquinone (1), smenospongidine (3),smenospongiarine (5), smenospongine (7), and their corresponding 5-epimers 2, 4, 6, and 8,isolated from the Palauan marine sponge Hippospongia sp., were examined regarding theireffects on TNF-α production in LPS-stimulated RAW 264.7 cells. 5-Epi-smenospongine(8) promoted the production of TNF-α to a level three times greater than the control at10 μM, but compounds 1-7 did not show apparent activity. The results suggest that thecis-decaline ring and a primary amine in the benzoquinone ring are necessary for activity.This is the first study to report the modulation of TNF-α production by a sesquiterpenequinone
    corecore