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In this study, we proposed a novel methodology based on total reflection X-ray fluorescence (TXRF) analysis for rapid evaluation of uranium radioactivity concentration in water samples, which will be found in the decommissioning field of Fukushima Daiichi Nuclear Power Plant containing various impurities. Sample solutions were prepared by mixing a multi-element standard solution containing uranium and thorium with an immersion liquid of the demolition debris in order to examine the effect of components of the demolition debris. An indium standard solution was added to the samples as an internal standard. Since the Rb Kα peak overlapped with the U Lα and Th Lα peaks, Gaussian fitting was performed to determine the net intensity of the U Lα peak. Moreover, due to the largely different contents of uranium and rubidium, reducing the number of fitting parameter made the Gaussian fitting easier. To determine the widths of the peaks, long-time TXRF measurement of the standard solutions for each element was performed. In the Gaussian fitting, only the peak intensities were considered as fitting parameters because the peak widths and peak energies could be fixed. The relative intensity of the U Lα peak was calculated as the net intensity of the U Lα peak normalized by that of the In Kα peak. The relative intensity was directly proportional to the uranium concentration. The estimated minimum detection limit of uranium with a measurement time of 15 min was significantly lower than the effluent standard value for uranium concentration in drainage water as defined by the Japanese Water Pollution Prevention Law, 20 mBq/cm3. All in all, we believe that this method will be useful in determining the uranium concentration in drainage water in the decommissioning field of Fukushima Daiichi Nuclear Power Plant.

Owing to the strong earthquake and subsequent tsunami in March 2011, the Fukushima Daiichi Nuclear Power Plant was exceedingly damaged and is currently under decommissioning. Herein, we propose a methodology to evaluate the uranium concentration in the drainage water from the decommissioning field. Model sample solutions were prepared by mixing multi-element standard solutions containing uranium with an immersion liquid containing demolition debris. A very small amount (10 μL) of the sample solutions was dropped onto a quartz optical flat directory with or without a chromatography resin separation. The total-reflection X-ray fluorescence (TXRF) spectrometry measurement was performed using a portable device. These measurements showed an overlap of the Rb Kα and U Lα peaks in the TXRF spectrum of the sample solution prepared without chromatography resin separation. By contrast, no overlap was observed in the TXRF spectrum of the sample solution after the separation using a chromatography resin. When the drainage water is composed of 0.04% U-234, 5% U-235, and 94.96% U-238, the measurement times in both methods (i.e., with and without pretreatment) required to attain detection limits lower than the effluent standard value are 15 and 5 min, respectively. Additionally, the detection limits, analysis times, required sample volumes, and procedures of the two methods are compared.

The analysis of uranium in environmental samples, quantified using total reflection X-ray fluorescence (TXRF) analysis, would be adversely affected by the presence of rubidium and strontium in larger amounts than uranium as coexisting elements. This is because the U Lα line at 13.61 keV is close to the Rb Kα line at 13.40 keV and the Sr Kα line at 14.17 keV. Using the U Lβ1 line (instead of the U Lα line), which does not overlap with the peaks of coexisting elements, we will be able to avoid these adverse effects. Since there is no TXRF device that can perform a quantitative analysis of uranium by using the U Lβ1 line, the following modifications were made to the existing device with the intention of rapid on-site analysis. The X-ray tube of the new device has a silver anode instead of a tungsten anode, and the sensitive area of the detector was expanded. In addition, the mechanism for adjusting the position of the sample stage was changed from manual to computerized control. These changes made it possible to screen uranium in environmental samples rapidly on site without chemical separation.

Two-dimensional (2D) cell cultures are essential for drug development and tumor research. However, the limitations of 2D cultures are widely recognized, and a better technique is needed. Recent studies have indicated that a strong physical contact between cells and 2D substrates induces cellular characteristics that differ from those of tumors growing in vivo. 3D cell cultures using various substrates are then developing; nevertheless, conventional approaches have failed in maintenance of cellular proliferation and viability, uniformity, reproducibility, and/or simplicity of these assays. Here, we developed a 3D culture system with inorganic nanoscale scaffolding using nanoimprinting technology (nano-culture plates), which reproduced the characteristics of tumor cells growing in vivo. Diminished cell-to-substrate physical contact facilitated spontaneous tumor cell migration, intercellular adhesion, and multi-cellular 3D-spheroid formation while maintaining cellular proliferation and viability. The resulting multi-cellular spheroids formed hypoxic core regions similar to tumors growing in vivo. This technology allows creating uniform and highly-reproducible 3D cultures, which is easily applicable for microscopic and spectrophotometric assays, which can be used for high-throughput/high-content screening of anticancer drugs and should accelerate discovery of more effective anticancer therapies.

Introduction 64 Cu-diacetyl-bis ( N 4 -methylthiosemicarbazone) ( 64 Cu-ATSM) is an imaging agent for positron emission tomography (PET) that targets hypoxic tumors. 64 Cu-ATSM is also reported to be a potential agent for internal radiotherapy. In a mouse colon carcinoma (Colon-26) model, we have shown that 64 Cu-ATSM preferentially localizes in intratumoral regions with a high density of CD133 + cells, which show characteristics of cancer stem cells or cancer stem cell-like cells (collectively referred here as CSCs). In this study, we evaluated the therapeutic effect of 64 Cu-ATSM in relation to CD133 expression using this model. Methods Systemic administration of 37 MBq 64 Cu-ATSM or saline was conducted twice within a 1-week interval to mice bearing 1-week-old Colon-26 tumors (days 0–7). At day 19, tumor size measurement, flow cytometry analysis and experimental lung metastatic assay were performed. The therapeutic effect of 64 Cu-ATSM on sorted CD133 + and CD133 − Colon-26 cells was also examined in vitro. Results In vivo studies showed that 64 Cu-ATSM treatment inhibited tumor growth. The percentage of CD133 + cells and metastatic ability in 64 Cu-ATSM treated tumors was decreased compared with that in control animals. In vitro studies demonstrated that 64 Cu-ATSM accumulated in cells under hypoxic conditions and incorporation of 64 Cu-ATSM under hypoxia caused cell death in both CD133 + and CD133 − cells in a similar extent. Conclusions 64 Cu-ATSM administration reduced tumor volume as well as the percentage of CD133 + cells and the metastatic ability of Colon-26 tumors. Together with our data, it is suggested that 64 Cu-ATSM accumulates in regions high in CD133 + highly tumorigenic cells and kills such regions by radiation, resulting in a decrease of the percentage of CD133 + cells.

Introduction 64 Cu-diacetyl-bis ( N 4 -methylthiosemicarbazone) ( 64 Cu-ATSM) is a potential imaging agent of hypoxic tumor for use with PET. Recent literature demonstrated that cancer cells expressing CD133, which is a frequently used marker for so-called cancer stem cells or cancer stem cell-like cells (collectively referred to here as CSCs), contribute to tumor's therapeutic resistance and metastasis ability. Culturing under hypoxia is also reported to enlarge the proportion of CD133 + cells, which would indicate survival advantage of CD133 + cells under hypoxia. Here, we investigated the relationships between 64 Cu-ATSM accumulation and existence of CD133 + cells using mouse colon carcinoma (colon-26) tumor. Methods Intratumor distribution of 64 Cu-ATSM and 18 F-fluorodeoxyglucose ( 18 FDG) was compared with immunohistochemical staining for CD133 with a colon-26 model. In vitro characterization of CD133 + colon-26 cells was also performed. Results In colon-26 tumors, 64 Cu-ATSM localized preferentially in regions with a high density of CD133 + cells. The percentage of CD133 + cells was 11-fold higher in 64 Cu-ATSM high-uptake regions compared with 18 FDG high- (but 64 Cu-ATSM low-) uptake regions. CD133 + colon-26 cells showed characteristics previously linked with CSCs in other cancer cell lines, such as high colony-forming ability, high tumor-initiating ability and enrichment under hypoxic cultivation. The proportion of CD133 + cells was enlarged by culturing under glucose starvation as well as hypoxia, and 64 Cu-ATSM uptake was increased under such conditions. Conclusions Our findings showed that, in colon-26 tumors, 64 Cu-ATSM accumulates in rich regions of CD133 + cells with characteristics of CSCs. Therefore 64 Cu-ATSM could be a potential imaging agent for rich regions of CD133 + cells, associated with CSCs, within tumors.

Introduction [1- 11 C]Acetate positron emission tomography (PET) is used for myocardial studies. In the myocardium, mitochondrial acetyl-CoA synthetase (ACSS1) mainly contributes to the radiopharmaceutical uptake. [1- 11 C]Acetate PET is also used for tumor diagnosis; however, the uptake mechanism of radiolabeled acetate in tumors remains unclear. Our previous study reported that cytosolic acetyl-CoA synthetase (ACSS2) was expressed in tumor cells and up-regulated under hypoxia, whereas expression of ACSS1 was negligible regardless of the oxygen conditions. We also indicated that ACSS2 is a bidirectional enzyme that controls acetyl-CoA/acetate metabolism in tumor cells. In this study, to elucidate the basic mechanism of tumor acetate uptake, we focused on ACSS2 and investigated the role of ACSS2 in the uptake of radiolabeled acetate in tumor cells. Methods [1- 14 C]Acetate uptake and ACSS2 expression were examined in four tumor cell lines under normoxia or hypoxia. An ACSS2 knockdown study was also performed. Results [1- 14 C]Acetate uptake was increased in the tumor cells under hypoxia. This pattern followed that of ACSS2 expression. The incorporated 14 C was mostly distributed in the lipid-soluble fractions, and this tendency increased under hypoxia. ACSS2 knockdown led to a corresponding reduction in [1- 14 C]acetate uptake in all tumor cell lines examined under normoxia and hypoxia. Conclusions ACSS2 plays an important role in the uptake of radiolabeled acetate in tumor cells, which is different from that in the myocardium, which mainly involves ACSS1. The uptake of radiolabeled acetate in tumors increased under hypoxia along with up-regulation of ACSS2 expression. This suggests a possible mechanism for acetate PET for tumors.

Severely burned patients often show various degrees of organ failures, and when several vital organs are involved mortality becomes extremely high. A study was undertaken to elucidate the actiology and clinical significance of multiple organ failure (MOF) in burned patients. One hundred and fifty-eight burned patients were analysed for organ failures in live vital organs or systems, the heart, lung, liver, kidney and blood clotting system. There were 91 organ failures observed in 34 patients, of which 26 had MOF. The most frequently affected organ was the lung, followed by the heart, kidney, liver and the blood clotting system. The mortality rate was 76·9 per cent in MOF and 1·5 per cent in non-MOF patients. Septicaemia was closely associated with the development of MOF. Also. inhalation injury and ‘shock’ were contributing factors to the morbidity. Five extensively burned patients had an early development of MOF without infectious foci and this type of early MOF was attributed to endotoxaemia possibly originating from the patient's own intestinal flora.