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Inhalation Toxicity of Metal Particles and Vapors
Published in Jacob Loke, Pathophysiology and Treatment of Inhalation Injuries, 2020
Tellurium is used in the steel industry in Cu and Pb alloys to provide increased resistance to corrosion and stress, in the glass industry as a coloring agent, and as an additive in rubber. Bismuth telluride is used as a thermocouple material in refrigeration equipment.
Nonisotopic Labeling
Published in Lelio G. Colombetti, Principles of Radiopharmacology, 2019
Tellurium is chemically similar to selenium. The isotope 123mTc has a T1/2 of 120 days and a single γ-photon of 159 keV, making it ideal for some scanning purposes. There have recently been reports of synthesis of telluronorcholestenols and tellurome-thionine.39 Its use is currently limited by the very low specific activity available and synthetic difficulties.
Radioactive Se And Te Labeled Imaging Agents
Published in Garimella V. S. Rayudu, Lelio G. Colombetti, Radiotracers for Medical Applications, 2019
Tellurium compounds can be prepared by procedures similar to those for selenium compounds.3,11-13 Te-123m tellurium metal is reduced by sodium borohydride,12 sodium metal in liquid ammonia,13 etc. to sodium ditelluride (Na2Te2) or sodium telluride (Na2Te) (Scheme 2). However, the reduction and subsequent alkylation reaction takes longer and requires more vigorous reaction conditions. In general, tellurium compounds are more difficult to prepare and less stable to light- and air-oxidation than the corresponding selenium compounds.
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].
Toxicity of microwave-assisted biosynthesized zinc nanoparticles in mice: a preliminary study
Published in Artificial Cells, Nanomedicine, and Biotechnology, 2019
Azad Salimi, Hamid-Reza Rahimi, Hamid Forootanfar, Elham Jafari, Atefeh Ameri, Mojtaba Shakibaie
In the present study, the oral route was selected as the current route of exposure for mice. The LD50 value of biogenic Zn NPs was evaluated to be above 5 g/kg in mice. According to the toxicity classification of the chemical substance, WHO and European Commission Directive 83/467/EEC, 1983, when LD50 was more than 2000 mg/kg, they were considered as practically non-toxic chemicals [23]. The LD50 value may be used to compare the acute toxicity of chemicals. One of the beneficial properties of biologically synthesized NPs was lower LD50 value and acute toxicity compared to their inorganic salt [5,24]. Changes in the body weight occurred as a measure of toxicity in a subacute study [5,24]. The body weight declined during 14 consecutive daily administrations of biogenic Zn NPs, especially at higher doses of 4 and 5 g/kg, and ZnSO4 at the dose of 100 mg/kg. This reduction was not found when lower doses (1, 2, and 3 g/kg) of biogenic Zn NPs were administrated. Studies have suggested that animals better tolerated high doses of biogenic trace elements (selenium and tellurium) than their inorganic forms and thus, low degree of toxicity may occur in animals treated with biogenic compounds [5,24].
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].