The interaction of gamma radiation with drugs used in cholinergic medications

Determination of toxicity and radioprotective properties of bacterial and fungal eumelanin pigments

PURPOSE

Determination of the protective property of melanin, an organic polymer class consisting of phenolic and/or indolic compounds isolated from bacteria and fungi, against fast neutron radiation. To show that these melanin samples, which also have antioxidant and metal chelating properties, can be used as an active ingredient for a drug to be developed against neutrons used in nuclear research and medicine.

MATERIALS AND METHODS

Bacterial and fungal media were prepared, and melanin pigments were produced and isolated. For molecular characterization of pigments, bacterial genomic DNA extraction, 16S rDNA gene amplification processes, and fungal genomic DNA extraction, ITS1, and ITS4 Gene Regions amplification were performed. The DEL assay was implemented to determine the genotoxicity properties of bacterial and fungal melanin pigments. Samples were prepared in a pad measuring 10 ml volume (60 × 15 mm) at a concentration of 0.2-1 microgram in 1% agarose gel for radiation-absorbed dose measurements. Absorption measurements were made using 241Am-Be fast neutron source and Canberra brand NP series BF3 gaseous detector to determine the neutron radiation absorption capacity of all samples. The results obtained to determine the absorption degrees of melanin samples were compared with paraffin and normal concrete, which are widely used in neutron radiation shielding studies.

RESULTS

Melanin pigments were obtained using different bacteria and fungi strains. Afterwards, the fast neutron radiation absorption capacity of these purified pigments were determined. Compared to reference samples, these pigments were found to have slightly lower radiation absorbing ability. In addition to these experiments, cytotoxicity tests were carried out using the Yeast DEL assay technique to evaluate the potential for use of these organic pigments in fields such as medicine and pharmacology. According to the results obtained from the tests, it was determined that these melanin samples did not have any toxic effects.

CONCLUSION

It was determined that these melanin samples have the potential to be used as a radioprotective drug active substance to protect the tissues and cells of people exposed to neutron radiation after a nuclear accident or nuclear war.Giving a drug that will be developed by using these active ingredients before or after people are exposed to a radiation environment can provide great benefits.

Photon interaction performance of various contrast agents: Theoretical and simulation results

In this study, total mass attenuation coefficient (μ/ρ) values in the energy range from 60 keV to 15 MeV for some contrast agents (Iopamidol, Metrizamide, Iohexol, Ioxaglic acid, Iopromide, Ioversol and Iopentol) were determined with the WinXCOM computer program and GEANT4 computer simulation code. Linear attenuation coefficients (μ), half value layers (HVL), tenth value layers (TVL), mean free paths (mfp), effective atomic numbers (Z_Eff) and effective electron densities (N_Eff) in the aforementioned energy range were obtained with the help of the calculated total mass attenuation coefficients. Energy absorption build-up factors (EABF) and exposure build-up factors (EBF) for contrast agents were calculated using the five-parameter geometric progression (G-P) fitting method in the energy region of 0.015 MeV ≤ E ≤ 15 MeV for different penetration depths up to 40 mfp with the help of the equivalent atomic numbers (Z_eqv). Kerma relative to air values were investigated in the energy region 0.001 MeV ≤ E ≤ 20 MeV. It has been observed that Ioxaglic acid is a good radiation absorber according to the other studied contrast agents. The present results may contribute to various application areas of radiation research.

Gamma, Fast Neutron, Proton, and Alpha Shielding Properties of Borate Glasses: A Closer Look on Lead (II) Oxide and Bismuth (III) Oxide Reinforcement

The purpose of this research was to investigate the shielding characteristics of high-amount heavy metal oxide and Eu3+-activated borate glasses based on 10La2O3–50HMO–(40–x) B2O3–xEu2O3 (x = 0, 0.5, 1, 2, and HMO = PbO, Bi2O3). Critical gamma radiation attenuation characteristics, particularly mass attenuation coefficients of investigated heavy metal oxide glass samples, were determined using Monte Carlo simulations and the Phy-x/PSD software. Following that, we looked at the half-value layer, mean free path, effective atomic number, and build-up factors across a broad energy range (0.015–15 MeV). According to the study’s results, the addition of Eu2O3 enhanced the mass attenuation coefficient and effective atomic number, while reducing the half-value layer, mean free path, and accumulation factors. In terms of gamma radiation attenuation, the LBi50BEu glass system surpassed the LPb50BEu glass system in terms of overall shielding properties against nuclear radiation. Additionally, the heavy metal oxide glass’ efficacy as a neutron shield was determined using fast neutron removal cross-sections (ΣR). LBi50BEu2 glass was shown to be more effective in preventing the penetration of charged particle radiation.

Investigation of neutron and gamma radiation protective characteristics of synthesized quinoline derivatives

PURPOSE

Quinoline is formed by various natural compounds, such as alkaloids from the cinchona plant, which exhibit various biological activities, and is an important building material for the development of new drugs. Quinoline can be used in anti-radiation drug development but radiation interaction properties must be determined.

MATERIAL AND METHODS

In this study, six types of synthesized quinoline derivatives were used. Fast neutron removal cross-section, mean free path, half value layer and transmission number were theoretically determined by using GEometry ANd Tracking 4 and FLUktuierende KAskade simulation codes for neutron shielding. Neutron dose absorption rates were determined using the ²⁴¹Am-Be fast neutron source and the Canberra NP series portable BF₃ gas proportional neutron detector. Gamma radiation shielding parameters were determined by using WinXCom and PSY-X/PSD software. Additionally, the genotoxic potentials of the derivatives were assessed by using the Ames/Salmonella bacterial reversion assay.

RESULTS AND CONCLUSIONS

Neutron shielding parameters such as removal cross-section, mean free path, half value layer and transmission number were theoretically determined for fast neutrons. To determine neutron absorption capacity of quinoline derivatives, neutron absorption, experiments were conducted. In addition, gamma radiation shielding parameters were calculated such as the mean free path (MFP), mass attenuation coefficient (µt), half value thickness layer (HVL) and effective atomic number (Zeff) in the energy range of 0.015-15 MeV. The results of the all quinoline derivatives have excellent fast neutron shielding power compared to ordinary concrete. In addition, all quinoline derivatives have been found to have the capacity to attenuate gamma radiation. Moreover, they absorb well in both types of radiation, do not cause secondary radiation, and they are genotoxically safe at the tested concentrations. This study has demonstrated that these products can be used as active ingredients for a drug to be developed against radiation.