An Integrated Analysis of Four Targeted Thorium Conjugates to Assess the 227Th and 223Ra Distribution and Tissue-Related Radiation.

Solutions of 203Hg-labelled phenyl mercuric acetate (PMA), phenyl mercuric chloride (PMC), ethyl mercuric chloride (EMC) and mercuric chloride (MC) were given to 4 groups of 3-6 rats by a single peroral injection, and the radioactivity in whole body of animals, feces and urine was measured every successive days with a Packard Armac Scintillation Counter, in order to investigate the body retention and excretion of radioactive mercury. The retained radioactivity in body decreased exponentially daily during the definite period after administration, namely, from about 10 th day in the cases of PMA and PMC, from the next day to administration of EMC and from 3rd day after administration of MC (Fig. 1-4), and the linear retention lines of Hg-compounds were depicted graphically on semi-logarithmic scale, and accordingly the biological half-lives of these radioactive mercury compounds were calculated from the lines. The periods showing exponential decreasing of radioactivity and the biological half-lives of mercury in those periods after administration of 4 kind of mercury compounds were shown as the following ; [table] The value of these calculated biological half-lives could be the result depending on the metabolic state of the 4 kind of compounds, ……absorption into blood, accumulation in the internal organs, clearance from the organs and metabolism in the interval……, and difference of the values among the compounds showed the difference of metabolic turn over rate among the compounds. The whole body count of animals after administration of MC fell to about 1% of initial count in 17 days, while in the cases of organic mercury compounds, over 2% of initial activity was still observed after 85, 63 and 107 days after a single administration of PMA, PMC and EMC, respectively.

100. 177Lu-PSMA molecular radiotherapy: Strategy to reduce organ at risks uptake

A primary standard source of radon-222 based on the HPGe detector

In this study, the spectrum due to radioactivity contained sand samples from famous beaches on the east coast of Gangwon-do was measured. The sand samples were seven famous beaches in Gangwon-do and were placed into a high-purity germanium detector (HPGe) using with an electric field, which is a semiconductor detector and subjected to a precision analysis of the gamma-rays emitted from the radionuclides in the sand by using a multichannel analyzer (MCA). To measure the concentration of the radionuclides, we obtained a spectrum by analyzing the gamma-rays emitted from the radionuclides for a measurement time of 8,000 seconds. The results show that of all the radionuclides, Tl-208 had the highest radioactivity at five of the seven beaches which K-40 had the highest radioactivity at the other two beaches. In conclusion, the radionuclides that were detected in the coastal sand samples from South Korea’s East Coast are natural radionuclides; however, they can affect of the human body internally. Therefore, the radioactivity levels need to be reduced and to be investigate further.

Radioprotective effects were investigated in mice which received subcutaneously a single dose of each inorganic metal: Co, Cu, Rb, Sr, Mo and W 24h post irradiation of 60Co γ-rays with a sublethal dose.The effects were observed in mice injected with Co at an optimum dosage of 20 mg/kg· body weight. Then to elucidate mechanisms of the effects, mice were injected with Co containing the radioactive tracer (60Co) following the radiation exposure, measured elimination of the radioactivity for 7 days, then sacrificed and divided to some tissues and organs. The radioactivity in whole body during this period resulted in a markedly higher retention than that for mice injected with [60Co] alone, as well as liver in the organs. These higher retentions appeared to be related to the radioprotective effects.

Huge amount of coal combustion residue (CCR) is being generated in India every year. Since coal contains some natural radionuclides, the CCR may contribute to the enhanced natural radiation background. Hence, it is important to monitor the natural radioactivity levels in Indian CCR samples. The present study aims to estimate the natural radioactivity levels in CCRs produced in Indian thermal power plants. Accordingly, six CCR samples from different thermal power plants were collected and packed to achieve secular equilibrium among daughter products of 226Ra. The samples were counted for activity of gamma radionuclides using high purity germanium detector based high resolution gamma spectrometer. Results show that 40K is the most abundant among analyzed radionuclides, and the lowest was observed for 226Ra. Secular equilibrium was observed between 228Ra and 228Th, whereas no equilibrium was observed between 226Ra and 238U. The activity concentration for 226Ra and its daughter products (214Pb and 214Bi) was found to be similar in CCR sample before and after equilibrium, indicating that progenies are in secular equilibrium in CCR. The X ray diffraction analysis of CCR indicates the presence of aluminosilicate as major fraction, which has potential of trapping of 226Ra and daughter products. The values observed are very low and similar to those observed in naturally occurring radioactive materials such as coal, soil, and sediment, hence are not of radiological concern with respect to human/environment.

Measurements of gamma-ray spectra, following the thermal neutron fission of ${}^{235}\mathrm{U}$ have been made using a high purity germanium detector at the University of Massachusetts Lowell (UML) Van de Graaff facility. The gamma spectra were measured at delay times ranging from 0.2 s to nearly 10 000 s following the rapid transfer of the fission fragments with a helium-jet system. On the basis of the known gamma transitions, forty isotopes have been identified and studied. By measuring the relative intensities of these transitions, the relative yields of the various precursor nuclides have been calculated. The results are compared with the recommended values listed in the ENDF/B-VI fission product data base (for the lifetimes and the relative yields) and those published in the Nuclear Data Sheets (for the beta branching ratios). This information is particularly useful for the cases of short-lived fission products with lifetimes of the order of fractions of a second or a few seconds. Independent yields of many of these isotopes have rather large uncertainties, some of which have been reduced by the present study.

The results of activation studies of TRIGA research reactor concrete shielding are given. Samples made of ordinary and barytes concrete were irradiated in the reactor to simulate neutron activation in the shielding concrete. Long-lived neutron-induced gamma-ray-emitting radioactive nuclides were measured in the samples with a high-purity germanium detector. The most active long-lived radioactive nuclides in the ordinary concrete samples were found to be 60Co and 152Eu. In the barytes concrete samples, the most active long-lived radioactive nuclides were 60Co, 133Ba, and 152Eu. Activation in the concrete was also calculated using the ORIGEN2 code and compared to experimental results. Simple radioactive nuclide generation and depletion calculation using one-group cross-section libraries provided together with the ORIGEN2 code did not give conservative results. Significant discrepancies were observed for some nuclides. For accurate long-lived radioactive nuclide generation in reactor shielding, material-specific cross-section libraries should be generated and verified by measurement.

Yoshida sarcoma cells labeled with 131I-iododeoxyuridine were inoculated into Donryu female rats intraperitoneally. In these animals, the fractional rate of cell death and migration from the peritoneal cavity were monitored by measuring the radioactivity in the whole body and extraperitoneal site with a whole body animal counter. The radioactivity of the tumor cells in ascites fluid was measured by a well type scintillation counter. 3H-TdR-labeled Yoshida sarcoma cells were inoculated into Donryu female rats intraperitoneally. The radioactivity in the DNA fractions from the lungs, liver, spleen, kidneys, solid tumor on the omentum and the tumor cells in the ascites fluid was measured by a liquid scintillation counter 24 and 96 hours after the intraperitoneal inoculation in order to chase changes in the anatomical distribution of the 3H-labeled tumor cells. The results are as follows : (1) The death rate of 131I-IUdR-labeled tumor cells inoculated intraperitoneally was 6.3% per day. Six hours after the inoculation of the 131I-IUdR-labeled tumor cells, 18.5% of the radioactivity were in the extraperitoneal tissues, indicating rapid migration of tumor cells from the peritoneal cavity. The extraperitoneal radioactivity did not change until 72 hours after the inoculation, then it was increased at a constant rate to 32.1% 120 hours after the inoculation. The rate of cell loss from the ascites fluid was 9.2% per day until 48 hours after inoculation and thereafter it was increased to 17.0% per day. (2) Radioavtivity present in the lungs, liver, spleen and kidneys 24 hours after the inoculation with 3H-TdR-labeled tumor cells was 1.27±0.05%of the total amount of radioactivity administered. Ninety-six hours after the inoculation, radioactivity distributed in these organs and solid tumor on the omentum was 8.49±0.19%. From these results, solid tumor on the omentum, liver and lungs were seemed to be the major place of the tumor cell migration. It was concluded that the tumor cell death and the migration from the peritoneal cavity might participate a deceleration in the growth curve of the tumor cells in ascites fluid.

The study describes the effects of subchronic 2,3-dimercaptopropane-l-sulfonate (DMPS) treatment for four weeks on the elimination of /sup 203/Hg-methylmercury injection i.p. in male Sprague-Dawley rats. Radioactivity in urine, feces and whole body as well as in tissues was measured in a whole body counter. Data show that during 28 days control rats eliminated 48.2 + or - 10.9 percent of the administered dose, DMPS treated rats 82.4 + or - 18.2 percent. Organ distribution showed an enrichment of /sup 203/Hg in kidneys, blood and skin as compared to the whole body in treated and control rats. Mercury concentrations were lowered to about 15-30 percent of control values in all tissues with the exception of skin (70 percent). (JMT)

Detection of malabsorption of vitamin B12 due to gastric or intestinal dysfunction

The use of a clinical linac in photonuclear experiments is a novel concept. At Akdeniz University a program has been started focused on inducing photonuclear reactions with a Philips SLI-25 clinical linac. A bremsstrahlung photon beam produced by the linac is used to create radioactive nuclei. The decay of said nuclei is observed with a high-purity germanium detector. During the course of the experiment the spectrum of the irradiated sample is recorded. By analyzing the spectrum the energies of gamma-ray transitions in the daughter nuclei as well as the half-life of the parent nucleus are obtained. The results obtained thus far, starting with Zinc nuclei will be presented.

Natural radioactivity in the high background radiation area at Erasama beach placer deposit of Orissa, India

USP7, which encodes a deubiquitylating enzyme, is among the most frequently mutated genes in pediatric T-ALL, with somatic heterozygous loss-of-function mutations (haploinsufficiency) predominantly affecting the subgroup that has aberrant TAL1 oncogene activation. Network analysis of > 200 T-ALL transcriptomes linked USP7 haploinsufficiency with decreased activities of E-proteins. E-proteins are also negatively regulated by TAL1, leading to concerted down-regulation of E-protein target genes involved in T-cell development. In T-ALL cell lines, we showed the physical interaction of USP7 with E-proteins and TAL1 by mass spectrometry and ChIP-seq. Haploinsufficient but not complete CRISPR knock-out of USP7 showed accelerated cell growth and validated transcriptional down-regulation of E-protein targets. Our study unveiled the synergistic effect of USP7 haploinsufficiency with aberrant TAL1 activation on T-ALL, implicating USP7 as a haploinsufficient tumor suppressor in T-ALL. Our findings caution against a universal oncogene designation for USP7 while emphasizing the dosage-dependent consequences of USP7 inhibitors currently under development as potential cancer therapeutics.

Balance studies designed to obtain information concerning the metabolic fate of gossypol in rats were carried out utilizing two groups of animals. One was fed a basal diet and the other the same diet plus 500 ppm of iron as FeSO4. Single doses of 5 mg each of14C‐labeled gossypol (spec. act. 19.8 μCi/mmole) were administered. The animals were maintained in metabolic cages and killed after various periods of time. The data indicate that gossypol was poorly absorbed from the gastrointestinal tract and rapidly eliminated from the animal body. Although the main route for gossypol elimination from the animal was by fecal excretion in both treatments, the percentage of the total activity eliminated via the feces varied and depended on the level of iron supplied in the diet. The results demonstrate that gossypol was least excreted via urine and that urinary excretion of radioactivity was diminished by iron supplementation to the diet. Most of the radioactivity retained was found in the contents of different parts of the gastrointestinal tract. Tissues, the liver, muscle, kidney and blood had the highest radioactivity, with the liver having the highest specific activity. The data also demonstrate that addition of iron to the ration diminishes14C radioactivity in the animal body. This effect might be attributed to the formation of chelates that could not be absorbed through the small intestine. Catalysis of the decarbonylation of gossypol by iron also appears to be a factor.