Chemistry and Isotopes of Iodine
Erwin Regoeczi in Iodine-Labeled Plasma Proteins, 2019
The principle of electron capture has already been described in Figure 5. It is quite common among iodine isotopes, this being the sole mode of decay for 123I and 125I, and part of the decay scheme for the I nuclides with mass numbers 118,119, 120, 121, 124, 126, and 128. Because of the conversion of one proton to a neutron by this process, the atomic number of the daughter is one less than that of the parent, whereas the mass number remains the same. Therefore, each iodine isotope undergoing electron capture transforms to tellurium of the corresponding atomic mass, e.g., , or., . Tellurium is the next element to I in period 5, group VI of the periodic table.
Radiochemical Processing of Activated Targets
Frank Helus, Lelio G. Colombetti in Radionuclides Production, 2019
Typically, enriched tellurium powder is packaged in aluminum during the irradiation. After EOB, the target is dissolved by heating in 7M H2SO4 with addition of an appropriate volume of 30% H2O2. During the subsequent distillation, additional H2O2 may be added to ensure that the 123I is in a distillable chemical form. Carrier iodine may be added and a nitrogen gas stream may be used to improve transfer into the NaOH trap. If only dilute NaOH is used in the receiving flask, a mixture of 123I-iodide and 123I-iodate is obtained. Addition of a small quantity of reducing agent, such as Na2S2O3 or Na2SO3, results in a pure 123I-iodide product. Using 200 mg of 124Te (96%) irradiated for 4 hr with 13 μA of 22 MeV protons, production yields of 65 mCi of 123I and 0.45 mCi of 124I (which is formed by the 124Te(p,n)124I reaction) were obtained if this distillation based processing scheme was used.5
Metals
Frank A. Barile in Barile’s Clinical Toxicology, 2019
Chemically, Se closely resembles sulfur and is related to tellurium. Like sulfur, it exists in several different forms. The burning of fossil fuels and coal accounts for much of the Se released into the environment. Se is incorporated into photoelectric devices (gray Se), giving the material a flat appearance; it imparts a scarlet red color to glass and enamels (red Se, sodium selenide); and it has the ability to decolorize glass. Sodium selenate is included in insecticides, while Se sulfide is available as a pharmaceutical agent for the treatment of skin diseases, including itchy and flaking skin of the scalp, acne, eczema, and seborrheic dermatitis.
Geochemical speciation and bioaccumulation of trace elements in different tissues of pumpkin in the abandoned soils: Health hazard perspective in a developing country
Published in Toxin Reviews, 2022
Md Saiful Islam, Md Kawser Ahmed, Abubakr M. Idris, Khamphe Phoungthong, Md Ahosan Habib, Ramal Ahmed Mustafa
For essential and toxic elements, samples were analyzed by using inductively coupled plasma mass spectrometer (ICP-MS, 7800). The calibration curves were prepared using Multi-element Standard XSTC-13 (Spex CertiPrep® USA) with R2 >0.999. Internal calibration standard solutions containing 1.0 mg/L of indium, yttrium, beryllium, tellurium, cobalt and thallium were used. Working standards were prepared daily in 5% (v/v) HNO3 at 69% ultrapure grade and were used. For each experiment, a run included blank, certified reference materials (NMIJ CRM 7303-a lake sediment and INCT-CF-3–corn flour) and samples were analyzed in duplicate to eliminate any batch-specific error (Table S2). The recoveries of essential and toxic elements in the certified reference materials ranged between 94% and 101% (Table S2).
Targeting signaling pathways involved in primordial follicle growth or dormancy: potential application in prevention of follicular loss and infertility
Published in Expert Opinion on Biological Therapy, 2022
Sara Ali Farhat, Forouq Jabbari, Parnian Jabbari, Nima Rezaei
Cyclophosphamide results in apoptosis and damage of the ovary by inducing overactivation of primordial follicles via stimulating the PI3K/PTEN/AKT pathway and phosphorylation and inhibition of FOXO3 which alters the dormancy of the primordial follicles. AS101, a nontoxic tellurium-based compound, is an immunomodulator that has anti-tumoral properties. There properties are exerted through inhibiting cytokines essential for tumoral cell proliferation (IL-10) which will eventually lead to a decrease in the expression of the anti-apoptotic protein Bcl-2 [29,74]. It is now believed to exert a protective effect on ovarian reserve by inhibiting Akt phosphorylation/activation induced by Cy [29]. It was reported that AS101 co-treatment in Cy-treated mice improved reproductive function where a greater number of pups along with larger ovaries and more corpora lutea were obtained in comparison with mice treated with Cy alone [75]. No abnormalities were found in litters born to AS101 treated mice. This shows that the quality of the oocytes is preserved. Moreover, the anti-cancer activity of Cy was enhanced by AS101 treatment, possibly due to reduced inflammation [76].
Stimuli-responsive nanoscale drug delivery systems for cancer therapy
Published in Journal of Drug Targeting, 2019
Li Li, Wu-Wei Yang, Dong-Gang Xu
Li and co-workers (2017) devised a block polymer (PEG-PUTe-PEG) with tellurium (Te) and PEG by coordination bonds. The polymer could be used to load drugs, and combine with the photosensitizer indocyanine green (ICG) to form controlled release nanoparticles (CDDP), so that the possibility of water molecules infiltrating into nanoparticles could be reduced, and the high stability and half-life of nanocarriers in the plasma might be ensured. After the irradiation of NIR, a certain amount of reactive oxygen species (ROS) would be produced. Tellurium was easily oxidised by ROS because of its low electronegativity, which would weaken the coordination of tellurium and CDDP and then CDDP would be rapidly released from the system and tellurium oxidated at the tumour site. Besides, the encapsulated ICG played a synergistic role in anti-tumour effects through the photothermolysis produced by temperature and laser irradiation [130].