High Levels Of Radioactivity Research Articles

In the Field Feasibility of a Simple Method to Check for Radioactivity in Commodities and in the Environment.

Introduction:Some release of radionuclides into the environment can be expected from the growing number of nuclear plants, either in or out of service. The citizen and the big organization could be both interested in simple and innovative methods for checking the radiological safety of their environment and of commodities, starting from foods.Methods:In this work three methods to detect radioactivity are briefly compared focusing on the most recent, which converts a smartphone into a radiation counter.Results:The results of a simple sensitivity test are presented showing the measure of the activity of reference sources put at different distances from each sensor.Discussion:The three methods are discussed in terms of availability, technology, sensitivity, resolution and usefulness. The reported results can be usefully transferred into a radiological emergency scenario and they also offer some interesting implication for our current everyday life, but show that the hardware of the tested smart-phone can detect only high levels of radioactivity. However the technology could be interesting to build a working detection and measurement chain which could start from a diffused and networked first screening before the final high resolution analysis.

Preventing Radiobleaching of Cyanine Fluorophores Enhances Stability of Nuclear/NIRF Multimodality Imaging Agents.

Despite the large interest in nuclear/optical multimodality imaging, the effect of radiation on the fluorescence of fluorophores remains largely unexplored. Herein, we report on the radiobleaching of cyanine fluorophores and describe conditions to provide robust radioprotection under practical (pre)clinical settings. We determined the radiosensitivity of several cyanine fluorescent compounds, including IRDye 800CW (800CW) and a dual modality imaging tetrapeptide containing DOTA as chelator and Dylight 800 as fluorophore, exposed to increasing activities of 111In, 68Ga, or 213Bi (γ, EC/β, and α emitter, respectively). An activity and type of radiation-dependent radiation-induced loss of fluorescence, radiobleaching, of 800CW was observed upon incubation with escalating activities of 111In, 68Ga, or 213Bi. 68Ga showed the largest radiolytic effect, followed by 111In and 213Bi. The addition of oxygen radical scavengers including ethanol, gentisic acid, and ascorbic acid (AA), provided a concentration dependent radioprotective effect. These results supported the hypothesis of a free radical-mediated radiobleaching mechanism. AA provided the most robust radioprotection over a wide range of concentrations and preserved fluorescence at much higher radioactivity levels. Overall, both near-infrared fluorescent compounds displayed similar sensitivity, except for 213Bi-irradiated solutions, where the dual modality construct exhibited enhanced radiolysis, presumably due to direct radiation damage from α particles. Concurrently, AA was not able to preserve fluorescence of the dual-modality molecule labeled with 213Bi. Our findings have important consequences for several research areas including ROS sensing, radiation-mediated drug release (uncaging), fluorescent dosimetry, and in the preparation of dual-modality radiopharmaceuticals.

Radiopharmaceutical chemistry of targeted radiotherapeutics, part 4: Strategies for 211At labeling at high activities and radiation doses of 211At α-particles

IntroductionAlpha particles are radiation of high energy and short range, properties that can lead to radiolysis-mediated complications in labeling chemistry at the high radioactivity levels required for clinical application. In previous papers in this series, we have shown that radiation dose has a profound effect on the astatine species that are present in the labeling reaction and their suitability for the synthesis of N-succinimidyl 3-[211At]astatobenzoate. The purpose of this study was to evaluate the effects of adding N-chlorosuccinimide (NCS) to the methanol solution used for initial isolation of 211At after distillation, a process referred to as 211At stabilization, on 211At chemistry after exposure to high radiation doses. MethodsHigh performance liquid chromatography was used to evaluate the distribution of 211At species present in methanol in the 500–65,000Gy radiation dose range and the synthesis of SAB from N-succinimidyl 3-(tri-n-butylstannyl)benzoate in the 500–120,000Gy radiation dose range using different 211At timeactivity combinations under conditions with/without 211At stabilization. ResultsIn the absence of NCS stabilization, a reduced form of astatine, At(2), increased with increasing radiation dose, accounting for about half the total activity by about 15,000Gy, while with stabilization, At(2) accounted for <10% of 211At activity even at doses >60,000Gy. SAB yields without stabilization rapidly declined with increasing dose, falling to ~20% at about 5000Gy while with stabilization, yields >80% were obtained with 211At solutions stored for more than 23h and receiving radiation doses >100,000Gy. ConclusionsAdding NCS to the methanol solution used for initial isolation of 211At is a promising strategy for countering the deleterious effects of radiolysis on 211At chemistry. Advances in knowledge and implications for patient careThis strategy could facilitate the ability to perform 211At labeling at sites remote from its production and at the high activity levels required for clinical applications.

Abstract 4232: PET imaging of galectin-3 expression with [18F]FPDTG for detection of early breast carcinoma lesions in dense breast tissue

Abstract Mammography is the gold standard for breast cancer detection with sensitivity of 85%, which decreases to 68% in women with dense breasts and to 48% in women with extremely dense breasts, making cancer detection challenging. Additional methods for breast cancer screening have been developed, including: contrast-enhanced mammography, tomosynthesis, automated whole breast ultrasound, advanced MRI and molecular imaging (99mTc-MIBI gamma camera; 18F-FDG). However, early detection and differential diagnosis of malignant vs benign breast lesions remains a major challenge in patients with dense breasts. We have been developing novel approaches to early detection and differential diagnosis of malignant vs benign breast lesions using PET imaging of galectin-3 (Gal-3), that is significantly overexpressed in breast carcinomas, as compared to pre-malignant lesions. We developed a novel radiotracer 3-[18F]fluorophenylthio-digalactoside (18F-FPTDG) with high binding affinity (Kd 14 nM) and specificity to Gal-3. In vitro radiotracer binding studies in a panel of MCF10-derived cell lines with different degrees of malignancy and Gal-3 expression, demonstrated a highly significant linear relationship between the level of Gal-3 expression and the magnitude of 18F-FPTDG binding to cell membranes (R2 = 0.99). Preliminary in vivo PET imaging studies with 18F-FPTDG in mice bearing MCF10DCIS tumor xenografts demonstrated a rapid bi-exponential clearance of 18F-FPTDG from the blood (fast and slow clearance half-times: 0.5 and 10.5 min, respectively). 18F-FPTDG cleared predominantly via the hepatobiliary route, as evidenced by high levels of radioactivity in the liver, increasing levels in duodenum and upper intestinal tract. The liver and kidney clearance followed mono-exponential kinetics with half-times of ∼120 min and 37 min, respectively. Renal clearance was more active in mice, as evidenced by higher amounts of radioactivity in the bladder. The magnitude of catabolism of [18F]FPDTG was negligible, as evidenced by very low levels of [18F]F2 accumulation in the bone at 60-75 min post injection. The level of accumulation of [18F]FPDTG-derived radioactivity in the lungs, muscles, and other organs and tissues was extremely low. Also, there was no measurable levels of [18F]FPDTG-derived radioactivity in the brain. In contrast, there were distinct regions in the breast carcinoma xenograft with higher levels of [18F]FPDTG, especially in the central regions (hypoxia). The half-time clearance of [18F]FPDTG from tumors was ∼8 min, which was about twice longer than clearance half-time from lungs and muscles - 4.5 and 4 min, respectively. Additional studies are being conducted in various breast tumor xenograft models, as well as in PyVmT transgenic mice, to assess the utility of PET/CT with [18F]FPDTG for differential diagnosis of benign vs malignant breast lesions and for biopsy guidance. Citation Format: Robin E. Bonomi, Vadim Popov, Thomas Mangner, Avraham Raz, Anthony F. Shields, Juri G. Gelovani. PET imaging of galectin-3 expression with [18F]FPDTG for detection of early breast carcinoma lesions in dense breast tissue. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 4232.

Pre-Quaternary rocks and sediments with a high level of radioactivity in Denmark

The pre-Quaternary sediments and rocks in Denmark generally have a low content of radioactive minerals and elements. Uranium, thorium and radium are built into mineral structures or are, for example, adsorbed on the surface of clay minerals, Fe-minerals or organic material. Radon (222Rn) is a radioactive noble insoluble gas with a half-life of 3.8 days. It belongs to the uranium (238U) decay chain where radon is formed from radium (226Ra). When Rn is formed by radioactive decay from Ra, the emanation process sends part of the radon produced into the pore spaces of rocks and soils. From here, the radon can enter and accumulate in buildings. The source of the radioactive materials in Danish sediments and rocks is primarily from weathered Precambrian crystalline rocks from Norway, Sweden, Finland and the Danish island of Bornholm. Physical and chemical weathering disintegrates these rocks and rivers transport the material into the Danish–Norwegian and Danish–Polish sedimentary basins.

137Cs monitoring in the meat of wild boar population in Slovakia

Currently, due to the elapsed time and the nature of the Chernobyl accident, the only artificial radionuclide present in the soil is 137Cs, with a physical half-life conversion of 30.17 years. The 137Cs is quickly integrated into a biological cycle, similar to potassium. Generally, radionuclides are characterized by their mobility in soil. Contamination of materials and food by radionuclides represent a serious problem and has a negative impact on human health. The threat of international terrorism and the inability to forestall the impact of natural disasters on nuclear energetic (Fukushima accident), are also reasons for continuous monitoring of food safety. According screening measurement performed in European countries, high radioactivity levels were reported in the wild boars muscles from Sumava (Czech Republic). Seasonal fluctuation of 137Cs activity in the wild boar meat samples was observed in the forests on the southern Rhineland. Monitoring of 137Cs activity in the wild boar meat samples in the hunting grounds in Slovakia was initiated based on the reports on exceeding limits of the content of radiocaesium in the meat of wild boar from the surrounding countries. The aim of this study was to determine the 137Cs post Chernobyl contamination of wild boars population in different hunting districts of Slovakia during 2013 - 2014. A total of 60 thigh muscle samples from wild boars of different age categories (4 months - 2 years) were evaluated. 137Cs activity was measured by gamma spectrometry (Canberra). Despite the fact Slovakia is closer to Chernobyl as Czech Republic and Germany, the 137Cs activity measured was very low and far below the permitted limit. The highest radiocaesium activity level measured in muscle was 37.2 Bq.kg-1 ±4.7%. Wild boar originated from Zlate Moravce district. The measurement results show, that 137Cs contamination levels of game in Slovakia are low. Radiocaesium activity in examined samples was very low and therefore consumption of wild boar meat does not represent a health risk problem.

Technologically elevated natural radioactivity and assessment of dose to workers around a granitic uranium deposit area, China

Gamma dose rates in a uranium site in Guangdong, China were measured based on different functioning areas (mining area, milling area, tailings area and downstream area); four representative soil profiles were measured with HP Ge gamma spectrometry. The gamma dose rates as well as annual effective dose overall exceeded the relevant values reported from other countries. Both the external and the internal hazard index overwhelmingly exceeded the recommended value. Some areas were heavily polluted with technologically elevated concentrations of 238U and 226Ra, while others were observed with extremely high background level of natural radioactivity, mainly stemming from granitic lithology.

Enhanced tumor retention of radioiodinated anti-epidermal growth factor receptor antibody using novel bifunctional iodination linker for radioimmunotherapy.

Radioimmunotherapy (RIT) uses an antibody labeled with a radionuclide to deliver cytotoxic radiation to a target tumor cells. Radioiodine is most commonly employed to prepare radiolabeled proteins (antibodies, peptides) for in vitro and in vivo applications. A major shortcoming of radioiodinated proteins prepared by direct labeling methods is their deiodination in vivo. For the preparation of more stable radioiodinated antibodies, we developed a new linker (N-(4-isothiocyanatobenzyl)-2-(3-(tributylstannyl)phenyl) acetamide (IBPA). This study evaluated the usefulness of IBPA as a linker for the stable radioiodinated internalizing antibody, cetuximab. Directly labeled cetuximab ([125I]-cetuximab) was prepared by the chloramine T method. To prepare indirectly labeled cetuximab using IBPA ([125I]-IBPA-cetuximab), IBPA was radioiodinated using chloramine-T to give N-(4-isothiocyanatobenzyl)-2-(3-[125I]phenyl)acetamide ([125I]-IBPA), which was purified by high performance liquid chromatography. [125I]-IBPA was then conjugated to cetuximab. In vitro target binding and internalizing assays were performed in PC9, LS174T, and FaDu cell lines. In vivo planar images were obtained using an Inveon SPECT scanner 3, 24, 48, and 168 h after i.v. injection of [125I]-cetuximab or [125I]-IBPA-cetuximab in athymic mice bearing LS174T tumor xenografts. Specific binding and internalized radioactivity of [125I]-IBPA-cetuximab were higher than those of [125I]-cetuximab in PC9, LS174T, and FaDu cell lines. In planar images scant radioactivity was evident in thyroid glands after injection of [125I]-IBPA-cetuximab, while a high level of radioactivity was present in thyroid glands after injection of [125I]-cetuximab. Tumor uptake value of [125I]-IBPA-cetuximab was higher than that of [125I]-cetuximab for up to 168 h. [125I]-IBPA-cetuximab is stable and resistant to deiodination in vivo. IBPA is a promising bi-functional linker for radioiodination of internalizing monoclonal antibodies for in vivo applications including radioimmunotherapy.

Ex Vivo and In Vivo Imaging and Biodistribution of Aptamers Targeting the Human Matrix MetalloProtease-9 in Melanomas.

The human Matrix MetalloProtease-9 (hMMP-9) is overexpressed in tumors where it promotes the release of cancer cells thus contributing to tumor metastasis. We raised aptamers against hMMP-9, which constitutes a validated marker of malignant tumors, in order to design probes for imaging tumors in human beings. A chemically modified RNA aptamer (F3B), fully resistant to nucleases was previously described. This compound was subsequently used for the preparation of F3B-Cy5, F3B-S-acetylmercaptoacetyltriglycine (MAG) and F3B-DOTA. The binding properties of these derivatives were determined by surface plasmon resonance and electrophoretic mobility shift assay. Optical fluorescence imaging confirmed the binding to hMMP-9 in A375 melanoma bearing mice. Quantitative biodistribution studies were performed at 30 min, 1h and 2 h post injection of 99mTc-MAG-aptamer and 111In-DOTA-F3B. 99mTc radiolabeled aptamer specifically detected hMMP-9 in A375 melanoma tumors but accumulation in digestive tract was very high. Following i.v. injection of 111In-DOTA-F3B, high level of radioactivity was observed in kidneys and bladder but digestive tract uptake was very limited. Tumor uptake was significantly (student t test, p<0.05) higher for 111In-DOTA-F3B with 2.0%ID/g than for the 111In-DOTA-control oligonucleotide (0.7%ID/g) with tumor to muscle ratio of 4.0. Such difference in tumor accumulation has been confirmed by ex vivo scintigraphic images performed at 1h post injection and by autoradiography, which revealed the overexpression of hMMP-9 in sections of human melanomas. These results demonstrate that F3B aptamer is of interest for detecting hMMP-9 in melanoma tumor.

Comparison between natural radioactivity levels andgeochemistry of some granitoids in western Turkey

Granitoids commonly include K-feldspar, biotite and zircon, apatite, titanite, allanite, and xenotime crystals, which are known to contain common radioactive elements. Radioactive isotopes of 40K, 238U, and 232Th can be harmful to human health with increasing dosage and their quantification should be well defined to assess the suitability of wall-rock granitoids for indoor and outdoor purposes. In this study, it is aimed to correlate the possible relationship between concentrations of natural radionuclides and SiO2, Na2O, K2O, and CaO together with elements U, Th, Zr, Y, Ba, Rb, and Sr to provide a basic approach to the compatibility of geochemical data with natural radioactivity levels of granitic to dioritic rocks in western Turkey. 226Ra, 228Ac, and 40K radioactivity concentrations of the granitoid samples from seven locations range between 15.6 ± 1.5 and 139.7 ± 11.2, 12.0 ± 1.1 and 93.4 ± 9.0, and 297.5 ± 15.5 and 880.2 ± 47.5 Bq/kg, respectively. The lowest 226Ra, 228Ac, and 40K values occur in the Karaburun granitoids while the Buldan granitoids have the highest values. Our data confirm that the silica-rich acidic granitoids have higher natural radioactivity levels than silica-poor basic granitoids and high natural radioactivity levels have been closely associated with high SiO2, Na2O, K2O, Rb, and Ba contents, which may be explained by postmagmatic events of metasomatism and alteration. CaO, Sr, Y, and Zr do not show any correlation with natural radioactivity levels. Natural radioactivity parameters of the studied granitoids are within the safe dosage limits specified in international standards and are safe for use as construction materials. However, metasomatized or strongly altered granitoids may have elevated natural radioactivity levels and hence careful attention is needed for such granitoids.

On feasibility of a closed nuclear power fuel cycle with minimum radioactivity

Practical implementation of a closed nuclear fuel cycle implies solution of two main tasks. The first task is creation of environmentally acceptable operating conditions of the nuclear fuel cycle considering, first of all, high radioactivity of the involved materials. The second task is creation of effective and economically appropriate conditions of involving fertile isotopes in the fuel cycle. Creation of technologies for management of the high-level radioactivity of spent fuel reliable in terms of radiological protection seems to be the hardest problem.

Targeting of MMP2 activity in malignant tumors with a 68Ga-labeled gelatinase inhibitor cyclic peptide

IntroductionElevated levels of gelatinases (matrix metalloproteinases 2/9, i.e., MMP2 and MMP9) are associated with tumor progression, invasion and metastasis, so these enzymes are potential targets for tumor imaging. The peptide c(KAHWGFTLD)NH2 (herein, C6) is a selective gelatinase inhibitor. Cy5.5-C6 has been visualized in many tumor models in vivo. However, the sensitivity and penetrance of optical imaging are poor. It is well known that positron emission tomography (PET) has a high detection sensitivity and Gallium-68 (68Ga) is an optimal PET radioisotope. Thus, in the present study, we developed a novel ligand, 68Ga-NOTA-C6, to image MMP2 activity in tumors. MethodsC6 was conjugated with the bifunctional chelator NOTA (1,4,7-triazacyclononanetriacetic acid) and labeled with 68Ga. In vitro uptake and binding analyses were performed by using SKOV3 cell lines, coincubating with or without the MMP inhibitor doxycycline. The biodistribution and PET imaging were conducted on SKOV3 ovarian tumor models. MMP2 expression in tumors was analyzed by immunohistochemistry (IHC). ResultsThe non-decay corrected yield of 68Ga-NOTA-C6 was 61.8%–63.3%. 68Ga-NOTA-C6 was stable in both physiological saline and human serum. The uptake of 68Ga-NOTA-C6 in SKOV3 cells increased with time, and could be blocked by doxycycline in a dose dependent manner. The results of biodistribution and PET imaging showed that high radioactivity concentrations of 68Ga-NOTA-C6 occurred in tumors. The ratios of tumor to blood, muscle and ovary and oviduct at 30, 60 and 120min p.i. were 2.78±0.54, 3.86±0.65, 0.48±0.14, and 1.73±0.36, 10.31±3.12, 1.22±0.10, and 2.50±0.78, 7.03±1.85, 0.97±0.25, respectively. The tracer was excreted mainly through the renal system, as evidenced by high levels of radioactivity in the kidneys. These data support the possibility of using 68Ga-NOTA-C6 in PET to visualize tumors that overexpress MMP2. Conclusions68Ga-NOTA-C6 is a potential radiopharmaceutical for the imaging of in vivo MMP2 activity in tumors.

From Chernobyl to Fukushima: an interdisciplinary framework for managing and communicating food security risks after nuclear plant accidents

This comparison of government disaster management and public communications after the Chernobyl and Fukushima nuclear accidents seeks to create a framework for disaster management that enhances food resilience (the ability of food systems to withstand perturbations that could cause disruption of food supply); and in the specific case of nuclear disasters, the avoidance of contaminated food and provision of alternative foods. This paper integrates food security, emergency management, and risk communications perspectives. Misinformation and incomplete information can bias decision-making and political actions. When risk communication is inadequate, the public reacts with fear, mistrust, panic and stress. People have difficulty deciding what they can safely eat and what they should not eat. Many choose to reject all food from affected regions, which can compromise food security. Lack of proper information may lead to such extremes in behavior as avoidance of dairy products and consumption of untested foods, which may in fact have high levels of radioactivity. The measures taken by the USSR after the Chernobyl disaster lacked consistency and clarity and were not effective in providing food security for the affected people. The government also demonstrated a lack of attention to social justice in its dealings with people who moved back to the contaminated area, ignoring government policy that they should stay out. Those people still suffer from food insecurity. In Japan, food that met government safety levels was available, but many consumers nonetheless questioned the safety of food supplies and farmers often were confused about production and marketing. In both the Chernobyl and Fukushima cases, the evacuation of affected people was aimed at reducing exposure to radiation and did not sufficiently consider neither the psychological and physical health impacts of resettlement nor the security and safety of food supplies. Government responses would have been more effective in some regions if a timely distribution program of adequate, safe alternative foods (especially radioprotectors) from non-affected areas had been initiated.

Analysis of the natural activities of radionuclides, heavy metals, and other poisonous elements in lead-free Sn–6.5Zn solders with different alloying elements

Problem statementSn–Zn solders are candidate alternatives to Sn–Pb-based solder alloys. With the increasing requirement for lead-free solders, the reliability of successor solders in microelectronics assemblies is in high demand. The elimination of radionuclides, heavy metals, and other poisonous elements in lead-free Sn–6.5Zn solders in the microelectronics industry is a worldwide goal. As a result, it is useful to identify the natural concentrations of radioactive nuclides, heavy metals and other poisonous trace elements (both macro- and micro-element contents), such as Au-196, Th-227, Ag-110M, Fe-59, Zn-65, Rb-89, Rh-106M, Bi-207, Cs-137, Eu-154, Sb-126, Eu-152, Co-56, Co-58, Co-60 and K-40. If this lead-free solder contains high concentrations of natural radioactive nuclides, then workers handling it might be exposed to significant levels of radiation. Therefore, it is important to determine the levels of radioactive nuclides in this solder to protect workers; these levels provide background for the safety rules and precautions that should be applied for those working in this field. ApproachThe levels of natural radionuclides (238U, 232Th, and 40K) and their daughter products contained in Sn–6.5Zn solders have been estimated via gamma-ray spectrometry using a 100% Hyper-Pure Germanium (HPGe) detector. ResultsThe mean activities due to radionuclides, heavy metals, and other poisonous elements were measured, and the results are summarised in tables. ConclusionThe results of this assessment obtained by gamma-ray spectroscopic analysis indicated the presence of high levels of natural radioactivity, heavy metals and other poisonous elements. This result implies that a comprehensive study should be conducted to protect workers from high doses of hazardous substances.

Pharmacokinetics of topically applied recombinant human keratinocyte growth factor-2 in alkali-burned and intact rabbit eye

Keratinocyte growth factor-2 (KGF-2), an effective agent in the development of epithelial tissue and regeneration during corneal wound healing, is a potential therapeutic option to treat the corneal diseases with corneal epithelial defects. However the tissue distribution and pharmacokinetics of KGF-2 have not been explored yet in eye upon topical application. Using 125I-labeled recombinant human KGF-2 (125I-rhKGF-2), tissue distribution of rhKGF-2 in alkali-burned and control rabbit eyes was studied. Our results revealed that 125I-rhKGF-2 was distributed to all eye tissues examined. The highest radioactivity level was found in the cornea, followed by iris, sclera, ciliary body, lens, aqueous humor, vitreous body, and serum in a greatest to least order. The levels of 125I-rhKGF-2 were higher in corneas of alkali-burned eyes than those in control eyes though without statistical significance. Calculated pharmacokinetic parameters of t1/2, Cmax, and Tmax of rhKGF-2 in the rabbit corneas were 3.4 h, 135.2 ng/ml, and 0.5 h, respectively. In iris, lens, aqueous humor, and tear, t1/2, Cmax, and Tmax values were 6.2, 6.5, 5.2, and 2.5 h; 23.2, 4.5, 24.1, and 29,498.9 ng/ml; and 1.0, 0.5, 0.5, and 1.0 h, respectively. Predominant and rapid accumulation of rhKGF-2 in corneas suggests that therapeutic doses of rhKGF-2 could be delivered by topical application for treatment of corneal diseases.

Relationship between biodistribution of a novel thymidine phosphorylase (TP) imaging probe and TP expression levels in normal mice.

Thymidine phosphorylase (TP) is a key enzyme in the pyrimidine nucleoside salvage pathway and its expression is upregulated in a wide variety of solid tumors. In mice, we previously observed high and specific accumulation levels of our TP imaging probe, radioiodinated 5-iodo-6-[(2-iminoimidazolidinyl)methyl]uracil (IIMU) not only in high-TP-expressing tumors, but also in the liver and small intestine. To clarify the reason for the high accumulation levels of radioiodinated IIMU in the liver and small intestine, we investigated the expression levels of TP in mice in comparison with the biodistribution of radioiodinated IIMU ((123)I-IIMU). BALB/cCrSlc mice were injected with (123)I-IIMU, and the radioactivity levels [%ID/g (normalized to a mouse of 25 g body weight)] in the tissues of interest were determined 0.5, 1, 3 and 24 h after the injection (n = 5, each time point). To determine the expression levels of TP, BALB/cCrSlc and ddy mice (n = 3/each strain) were euthanized, and the heart, liver, lung, spleen, kidney, stomach, small intestine, large intestine and brain were collected. The mRNA and protein expression levels of TP in these organs were examined by quantitative reverse transcription-polymerase chain reaction and western blot analyses, respectively. In BALB/cCrSlc mice administered (123)I-IIMU, markedly high radioactivity levels were observed in the liver [1.568 ± 0.237 (%ID/g)] and small intestine [0.506 ± 0.082 (%ID/g)], whereas those in the other tissues were fairly low [<0.010 ± 0.003 (%ID/g)] 30 min after the injection. The highest expression levels of TP mRNA were also observed in the liver and small intestine among the tissues tested. Immunoblotting showed intense immunoreactive bands of the TP protein for the liver and small intestine, whereas no notable bands were detected for other tissues. Similar expression profiles of TP mRNA and protein were observed in ddy mice. We confirmed TP expression in various tissues of mice at the mRNA and protein levels: high TP expression levels were observed in the liver and small intestine. These high TP expression levels are consistent with the high accumulation levels of (123)I-IIMU in these tissues. Our results may provide important information about the physiological accumulation of (123)I-IIMU, which may be useful for the clinical diagnostic imaging of TP.

2P1-Q01 半円型全方向車輪を用いた除染ロボットの開発

Fukushima daiichi nuclear power station are contaminated with high levels of radioactivity. Robot performing decontamination activity is necessary because human can not go in the building. When performing the decontamination activities, it is necessary to prevent diffusion of contaminants and get over the step in the building. To solve this problem, We made a robot named "SHAR" which is able to do decontamination activities. This robot was using 8 mecanum wheels that was cut in half. As a result, it is possible to overcome the steps of 100 [mm] in the forward and backward direction, and 50 [mm] in the sideways direction.

Assessment of Activity Concentration of Radionuclides in Sediment from Oil Producing Communities of Delta State, Nigeria

Activity concentrations of twenty-six (26) samples of sediment collected from rivers from eleven (11) oil-producing communities and two (2) non-oil producing communities in Delta state of Nigeria were studied. Hyper Purity Germanium (HPGe) Detector was used for counting and detection of radionuclide content of all samples. Results of the samples analysed showed that the radioactivity concentrations of K40, Th232 and U238 in the sediment samples from oil-producing areas range from 32.47 Bq·kg-1 to 525.1 Bq·kg-1 with an average of 302.15 Bq·kg-1, 6.31 Bq·kg-1 to 19.33 Bq·kg-1 with an average of 11.66 Bq·kg-1, and 4.45 Bq·kg-1 to 18.69 Bq·kg-1 with an average of 8.66 Bq·kg-1 respectively. Activity concentrations at the control site ranged from 3.15 Bq·kg-1 to 4.80 Bq·kg-1, 2.27 Bq·kg-1 to 4.18 Bq·kg-1 and 1.15 Bq·kg-1 to 1.76 Bq·kg-1 for K40, Th232 and U238. These values are within the world average; natural radioactivity mapping of the study area is carried out using the Surfer software. Statistical analysis of the results showed that there is a significant difference between the radionuclide concentrations of the sediment samples from rivers in the oil producing site compared to results from non-oil producing communities, except for one of the oil producing site samples (Idumuesah) which has values that are close to those from the control sites for K40. The values of the radiological assessment indices obtained were observed to be within the permissible maximum values; hence the radiation hazard at study areas are negligible. However, concentration values of studied radionuclide at the oil-producing study areas were observed to be higher than values from the non-oil producing sites in most cases. It could therefore be reported that the operations of the oil companies in Delta state of Nigeria may have contributed to the high radioactivity level of the river sediments. Although the concentration at the time of this study poses no risk, further industrial activities in the study area may raise the activity concentration and radiological burden in the future.

New neutral and lipophilic technetium complexes based on a cytectrene moiety: synthesis, characterization and biological evaluation

Abstract The synthesis, characterization and biological evaluation of five neutral and lipophilic 99mTc-complexes, so-called cytectrenes, obtained from N-substitutedferrocenecarboxamide derivatives are reported. N-substitutedferrocenecarboxamide starting materials were obtained in two steps, with good yield and were fully characterized by classical spectroscopic methods including X-ray diffraction analysis for one of them. Using a microwave strategy for the 99mTc-radiolabelling step, each cytectrene were obtained quickly (radiolabelling time &lt; 5 min), from modest to good yield. The 99mTc-complexes, characterized by HPLC comparison with cold rhenium complex analogues, are stable, neutral and lipophilic (log P o/w ranged between 1.8 and 2.9). Unfortunately, despite such suitable features, in vivo studies of two of them gave poor results, in terms of brain uptake. Both radiocompounds exhibited the maximum brain accumulation of 0.31% ID/g and 0.26% ID/g at 5 min post-injection, respectively, followed by a very fast washout from the brain (0.06% ID/g and 0.07% ID/g at 30 min post-injection, respectively). Although our ligand systems exhibited high stability against exchange reactions with blood proteins, the high radioactivity level in stomach, increasing with time, suggests in vivo decomposition of our complex to pertechnetate.

Estradiol transfer from male big brown bats (Eptesicus fuscus) to the reproductive and brain tissues of cohabiting females, and its action as a pheromone

The powerful estrogen, 17β-estradiol, has been found to pass from male excretions to the reproductive organs, brain, and other tissues of cohabiting females in laboratory mice. The current studies were designed to examine whether this phenomenon also occurs in big brown bats (Eptesicus fuscus), a mammal appropriate for testing cross-species generality because of its phylogenetic distance from mice. When tritiated estradiol (3H-E2) was administered directly on the nasal area of adult female bats, radioactivity was reliably observed in the uterus and ovaries, and also in the brain and other tissues. When 3H-E2 was applied to the skin, radioactivity was observed in reproductive and other peripheral tissues. We injected male bats with minute quantities of 3H-E2 and housed each of them directly with groups of adult females for 48h. We then measured radioactivity in male and female bat tissues. In each of several replications of one male housed with three females, radioactivity was reliably observed in the uterus of all females, and in many other tissues in almost every female. Measurement in the organs of males directly exposed to 3H-E2 showed high levels of radioactivity in the testes and especially the epididymides. These data indicate that estradiol is transferred from males to females, likely via absorptions from males’ excretions and potentially also via intravaginal exposure during mating. Given the potency of estradiol in regulating female reproductive physiology and behavior, our data strongly suggest the potential for pheromonal action whereby male mammals induce sexual receptivity and ovulation in females.