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Advances in Pharmacology (San Diego,... 2023Tungsten is an emerging contaminant in the environment. Research has demonstrated that humans are exposed to high levels of tungsten in certain settings, primarily due...
Tungsten is an emerging contaminant in the environment. Research has demonstrated that humans are exposed to high levels of tungsten in certain settings, primarily due to increased use of tungsten in industrial applications. However, our understanding of the potential human health risks of tungsten exposure is still limited. An important point we have learned about the toxicity profile of tungsten is that it is complex because tungsten can often augment the effects of other co-exposures or co-stressors, which could result in greater toxicity or more severe disease. This has shaped the tungsten toxicology field and the types of research questions being investigated. This has particularly been true when evaluating the toxicity profile of tungsten metal alloys in combination with cobalt. In this chapter, the current state of the tungsten toxicology field will be discussed focusing on data investigating tungsten carcinogenicity and other major toxicities including pulmonary, cardiometabolic, bone, and immune endpoints, either alone or in combination with other metals. Environmental and human monitoring data will also be discussed to highlight human populations most at risk of exposure to high concentrations of tungsten, the forms of tungsten present in each setting, and exposure levels in each population.
Topics: Humans; Tungsten; Carcinogenesis
PubMed: 36858771
DOI: 10.1016/bs.apha.2022.10.004 -
Journal of Applied Clinical Medical... Oct 2021The goal of this work was to develop and test nontoxic electron collimation technologies for clinical use.
PURPOSE
The goal of this work was to develop and test nontoxic electron collimation technologies for clinical use.
METHODS
Two novel technologies were investigated: tungsten-silicone composite and 3D printed electron cutouts. Transmission, dose uniformity, and profiles were measured for the tungsten-silicone. Surface dose, relative dose output, and field size were measured for the 3D printed cutouts and compared with the standard cerrobend cutouts in current clinical use. Quality assurance tests including mass measurements, Megavoltage (MV) imaging, and drop testing were developed for the 3D printed cutouts as a guide to safe clinical implementation.
RESULTS
Dose profiles of the flexible tungsten-silicone skin shields had an 80-20 penumbra values of 2-3 mm compared to 7-8 mm for cerrobend. In MV transmission image measurements of the tungsten-silicone, 80% of the pixels had a transmission value within 2% of the mean. An ∼90% reduction in electron intensity was measured for 6 MeV and a 6.4 mm thickness of tungsten-silicone and 12.7 mm thickness for 16 MeV. The maximum difference in 3D printed cutout versus cerrobend output, surface dose, and full width at half-maximum (FWHM) was 1.7%, 1.2%, and 1.5%, respectively, for the 10 cm × 10 cm cutouts.
CONCLUSIONS
Both flexible tungsten-silicone and 3D printed cutouts were found to be feasible for clinical use. The flexible tungsten-silicone was of adequate density, flexibility, and uniformity to serve as skin shields for electron therapy. The 3D printed cutouts were dosimetrically equivalent to standard cerrobend cutouts and were robust enough for handling in the clinical environment.
Topics: Electrons; Humans; Radionuclide Imaging; Radiotherapy Planning, Computer-Assisted; Tungsten
PubMed: 34480841
DOI: 10.1002/acm2.13398 -
Frontiers in Public Health 2023The hepatotoxicity of exposure to a single heavy metal has been examined in previous studies. However, there is limited evidence on the association between heavy metals...
OBJECTIVE
The hepatotoxicity of exposure to a single heavy metal has been examined in previous studies. However, there is limited evidence on the association between heavy metals mixture and non-alcoholic fatty liver disease (NAFLD) and metabolic-associated fatty liver disease (MAFLD). This study aims to investigate the associations of 13 urinary metals, individually and jointly, with NAFLD, MAFLD, and MAFLD components.
METHODS
This study included 5,548 adults from the National Health and Nutrition Examination Survey (NHANES) 2003-2018. Binary logistic regression was used to explore the associations between individual metal exposures and MAFLD, NAFLD, and MAFLD components. Bayesian kernel machine regression (BKMR) and Quantile-based g-computation (QGC) were used to investigate the association of metal mixture exposure with these outcomes.
RESULTS
In single metal analysis, increased levels of arsenic [OR 1.09 (95%CI 1.03-1.16)], dimethylarsinic acid [1.17 (95%CI 1.07-1.27)], barium [1.22 (95%CI 1.14-1.30)], cobalt [1.22 (95%CI 1.11-1.34)], cesium [1.35 (95%CI 1.18-1.54)], molybdenum [1.45 (95%CI 1.30-1.62)], antimony [1.18 (95%CI 1.08-1.29)], thallium [1.49 (95%CI 1.33-1.67)], and tungsten [1.23 (95%CI 1.15-1.32)] were significantly associated with MAFLD risk after adjusting for potential covariates. The results for NAFLD were similar to those for MAFLD, except for arsenic, which was insignificantly associated with NAFLD. In mixture analysis, the overall metal mixture was positively associated with MAFLD, NAFLD, and MAFLD components, including obesity/overweight, diabetes, and metabolic dysfunction. In both BKMR and QGC models, thallium, molybdenum, tungsten, and barium mainly contributed to the positive association with MAFLD.
CONCLUSION
Our study indicated that exposure to heavy metals, individually or cumulatively, was positively associated with NAFLD, MAFLD, and MAFLD components, including obesity/overweight, diabetes, and metabolic dysfunction. Additional research is needed to validate these findings in longitudinal settings.
Topics: Adult; Humans; Non-alcoholic Fatty Liver Disease; Molybdenum; Nutrition Surveys; Thallium; Barium; Arsenic; Bayes Theorem; Overweight; Tungsten; Obesity
PubMed: 36950101
DOI: 10.3389/fpubh.2023.1133194 -
Toxicology Feb 2022Molybdenum, lithium, and tungsten are constituents of many products, and exposure to these elements potentially occurs at work. Therefore it is important to determine at... (Review)
Review
Molybdenum, lithium, and tungsten are constituents of many products, and exposure to these elements potentially occurs at work. Therefore it is important to determine at what levels they are toxic, and thus we set out to review their pulmonary toxicity, genotoxicity, and carcinogenicity. After pulmonary exposure, molybdenum and tungsten are increased in multiple tissues; data on the distribution of lithium are limited. Excretion of all three elements is both via faeces and urine. Molybdenum trioxide exerted pulmonary toxicity in a 2-year inhalation study in rats and mice with a lowest-observed-adverse-effect concentration (LOAEC) of 6.6 mg Mo/m. Lithium chloride had a LOAEC of 1.9 mg Li/m after subacute inhalation in rabbits. Tungsten oxide nanoparticles resulted in a no-observed-adverse-effect concentration (NOAEC) of 5 mg/m after inhalation in hamsters. In another study, tungsten blue oxide had a LOAEC of 63 mg W/m in rats. Concerning genotoxicity, for molybdenum, the in vivo genotoxicity after inhalation remains unknown; however, there was some evidence of carcinogenicity of molybdenum trioxide. The data on the genotoxicity of lithium are equivocal, and one carcinogenicity study was negative. Tungsten seems to have a genotoxic potential, but the data on carcinogenicity are equivocal. In conclusion, for all three elements, dose descriptors for inhalation toxicity were identified, and the potential for genotoxicity and carcinogenicity was assessed.
Topics: Animals; Body Burden; Carcinogenicity Tests; Cell Transformation, Neoplastic; Dose-Response Relationship, Drug; Humans; Inhalation Exposure; Lithium Chloride; Lung; Metal Nanoparticles; Molybdenum; Mutagenicity Tests; Neoplasms; Oxides; Risk Assessment; Tungsten
PubMed: 35026344
DOI: 10.1016/j.tox.2022.153098 -
Molecules (Basel, Switzerland) Jun 2022Throughout the previous ten years many scientists took inspiration from natural molybdenum and tungsten-dependent oxidoreductases to build active site analogues. These... (Review)
Review
Throughout the previous ten years many scientists took inspiration from natural molybdenum and tungsten-dependent oxidoreductases to build active site analogues. These studies not only led to an ever more detailed mechanistic understanding of the biological template, but also paved the way to atypical selectivity and activity, such as catalytic hydrogen evolution. This review is aimed at representing the last decade's progress in the research of and with molybdenum and tungsten functional model compounds. The portrayed systems, organized according to their ability to facilitate typical and artificial enzyme reactions, comprise complexes with dithiolene ligands, resembling molybdopterin, as well as entirely non-natural nitrogen, oxygen, and/or sulfur bearing chelating donor ligands. All model compounds receive individual attention, highlighting the specific novelty that each provides for our understanding of the enzymatic mechanisms, such as oxygen atom transfer and proton-coupled electron transfer, or that each presents for exploiting new and useful catalytic capability. Overall, a shift in the application of these model compounds towards uncommon reactions is noted, the latter are comprehensively discussed.
Topics: Iron-Sulfur Proteins; Ligands; Molybdenum; Organometallic Compounds; Oxidoreductases; Oxygen; Tungsten
PubMed: 35744820
DOI: 10.3390/molecules27123695 -
Molecules (Basel, Switzerland) Sep 2022This article gives an overview of the research activity of the LAC2 team at LCC developed at Castres in the field of sustainable chemistry with an emphasis on the... (Review)
Review
This article gives an overview of the research activity of the LAC2 team at LCC developed at Castres in the field of sustainable chemistry with an emphasis on the collaboration with a research team from the University of Zagreb, Faculty of Science, Croatia. The work is situated within the context of sustainable chemistry for the development of catalytic processes. Those processes imply molecular complexes containing oxido-molybdenum, -vanadium, -tungsten or simple polyoxometalates (POMs) as catalysts for organic solvent-free epoxidation. The studies considered first the influence of the nature of complexes (and related ligands) on the reactivity (assessing mechanisms through DFT calculations) with model substrates. From those model processes, the work has been enlarged to the valorization of biomass resources. A part concerns the activity on vanadium chemistry and the final part concerns the use of POMs as catalysts, from molecular to grafted catalysts, (ep)oxidizing substrates from fossil and biomass resources.
Topics: Catalysis; Molybdenum; Oxidation-Reduction; Tungsten; Vanadium
PubMed: 36144747
DOI: 10.3390/molecules27186011 -
Molecules (Basel, Switzerland) Jul 2022The high price of noble metal resources limits its commercial application and stimulates the potential for developing new catalysts that can replace noble metal... (Review)
Review
The high price of noble metal resources limits its commercial application and stimulates the potential for developing new catalysts that can replace noble metal catalysts. Tungsten-based catalysts have become the most important substitutes for noble metal catalysts because of their rich resources, friendly environment, rich valence and better adsorption enthalpy. However, some challenges still hinder the development of tungsten-based catalysts, such as limited catalytic activity, instability, difficult recovery, and so on. At present, the focus of tungsten-based catalyst research is to develop a satisfactory material with high catalytic performance, excellent stability and green environmental protection, mainly including tungsten atomic catalysts, tungsten metal nanocatalysts, tungsten-based compound nanocatalysts, and so on. In this work, we first present the research status of these tungsten-based catalysts with different sizes, existing forms, and chemical compositions, and further provide a basis for future perspectives on tungsten-based catalysts.
Topics: Catalysis; Metals; Tungsten
PubMed: 35897927
DOI: 10.3390/molecules27154751 -
Respiratory Medicine Aug 2017Cobalt exposure in the hard metal and bonded diamond tool industry is a well-established cause of ILD. The primary theories regarding the underlying mechanism of cobalt... (Review)
Review
Cobalt exposure in the hard metal and bonded diamond tool industry is a well-established cause of ILD. The primary theories regarding the underlying mechanism of cobalt related ILD include an immunologic mechanism and an oxidant injury mechanism. Cobalt related ILD may present in subacute and chronic forms and often has associated upper respiratory symptoms. The evaluation begins with a thorough occupational history and includes PFTs, HRCT, and bronchoalveolar lavage. HRCT findings are nonspecific and may resemble NSIP, UIP, sarcoidosis, or HP. The finding of cannibalistic multinucleated giant cells is diagnostic provided there is a history of exposure and appropriate changes on imaging; however, when these cells are not found on lavage, lung biopsy is required for diagnosis. Giant cell interstitial pneumonia is the classic pathologic pattern, but cobalt related ILD may also present with pathologic findings of UIP, DIP, or HP. When cobalt related ILD is suspected, removal from exposure is the most important step in treatment. Case reports suggest that treatment with steroids results in symptomatic, physiologic, and radiographic improvement.
Topics: Alloys; Bronchoalveolar Lavage; Cobalt; Giant Cells; Humans; Inhalation Exposure; Lung Diseases, Interstitial; Occupational Exposure; Respiratory Function Tests; Tomography, X-Ray Computed; Treatment Outcome; Tungsten
PubMed: 28732841
DOI: 10.1016/j.rmed.2017.06.008 -
Metal Ions in Life Sciences Mar 2020The last 20 years have seen a dramatic increase in our mechanistic understanding of the reactions catalyzed by pyranopterin Mo and W enzymes. These enzymes possess a...
The last 20 years have seen a dramatic increase in our mechanistic understanding of the reactions catalyzed by pyranopterin Mo and W enzymes. These enzymes possess a unique cofactor (Moco) that contains a novel ligand in bioinorganic chemistry, the pyranopterin ene-1,2-dithiolate. A synopsis of Moco biosynthesis and structure is presented, along with our current understanding of the role Moco plays in enzymatic catalysis. Oxygen atom transfer (OAT) reactivity is discussed in terms of breaking strong metal-oxo bonds and the mechanism of OAT catalyzed by enzymes of the sulfite oxidase (SO) family that possess dioxo Mo(VI) active sites. OAT reactivity is also discussed in members of the dimethyl sulfoxide (DMSO) reductase family, which possess des-oxo Mo(IV) sites. Finally, we reveal what is known about hydride transfer reactivity in xanthine oxidase (XO) family enzymes and the formate dehydrogenases. The formal hydride transfer reactivity catalyzed by xanthine oxidase family enzymes is complex and cleaves substrate C-H bonds using a mechanism that is distinct from monooxygenases. The chapter primarily highlights developments in the field that have occurred since ~2000, which have contributed to our collective structural and mechanistic understanding of the three canonical pyranopterin Mo enzymes families: XO, SO, and DMSO reductase.
Topics: Biocatalysis; Molybdenum; Sulfite Oxidase; Tungsten
PubMed: 32851830
DOI: 10.1515/9783110589757-015 -
Sensors (Basel, Switzerland) Apr 2022Close monitoring of vital physiological parameters is often key in following the evolution of certain medical conditions (e.g., diabetes, infections, post-operative... (Review)
Review
Close monitoring of vital physiological parameters is often key in following the evolution of certain medical conditions (e.g., diabetes, infections, post-operative status or post-traumatic injury). The allocation of trained medical staff and specialized equipment is, therefore, necessary and often translates into a clinical and economic burden on modern healthcare systems. As a growing field, transient electronics may establish fully bioresorbable medical devices capable of remote real-time monitoring of therapeutically relevant parameters. These devices could alert remote medical personnel in case of any anomaly and fully disintegrate in the body without a trace. Unfortunately, the need for a multitude of biodegradable electronic components (power supplies, wires, circuitry) in addition to the electrochemical biosensing interface has halted the arrival of fully bioresorbable electronically active medical devices. In recent years molybdenum (Mo) and tungsten (W) have drawn increasing attention as promising candidates for the fabrication of both energy-powered active (e.g., transistors and integrated circuits) and passive (e.g., resistors and capacitors) biodegradable electronic components. In this review, we discuss the latest Mo and W-based dissolvable devices for potential biomedical applications and how these soluble metals could pave the way towards next-generation fully transient implantable electronic systems.
Topics: Electric Power Supplies; Electronics; Humans; Molybdenum; Prostheses and Implants; Tungsten
PubMed: 35459047
DOI: 10.3390/s22083062