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Inhalation Toxicity of Metal Particles and Vapors
Published in Jacob Loke, Pathophysiology and Treatment of Inhalation Injuries, 2020
Industrial exposure to cobalt salts leads to respiratory effects, although there is some question as to whether cobalt is the sole agent responsible for these effects. Most industrial exposures come from cemented carbide industry where workers exposed to 0.1 to 0.2 mg Co/m3 have shown mild to fibrotic pulmonary changes; (Coates and Watson, 1971). Sensitization may be an important part of this effect. Experimental studies in animals, however, confirm the lung-irritant effect of the metal as used in this industry but not of other cobalt compounds. NIOSH (1978b) considered it reasonable to consider all cobalt compounds as being capable of causing lung fibrosis. Although current data are not conclusive, it appears that cobalt metal, cobalt salts, and cobalt carbonyl do not cause human cancer. Industrial cases where malignancy has been associated with metals have usually involved exposure to a mixture (for example, tungsten or titanium carbide and cobalt cementing metal), thereby preventing assignment of causation to one specific metal such as cobalt.
Radiation Hormesis in Cancer
Published in T. D. Luckey, Radiation Hormesis, 2020
Cobalt is an essential element. It is readily absorbed; it is excreted primarily in urine. An adult eats about 0.3 mg/d. The amount in the body is relatively constant throughout life, 2 to 5 mg of cobalt. Its distribution is: 40% in muscle, 14% in bone, and 46% in other soft tissues; liver, bone marrow and spleen are rich in Co. About 100 μg is in the form of vitamin B12. Large doses have a half life of 7 days. Excess Co salts ingestion causes nausea and vomiting. The toxicity of cobalt involves muscle and blood dyscrasias. Injected cobalt is carcinogenic. Cobalt dust may cause dermatitis or pulmonary disease. No studies were found in which low doses of 60Co were administered.
Models of Focal Epilepsy in Rodents
Published in Steven L. Peterson, Timothy E. Albertson, Neuropharmacology Methods in Epilepsy Research, 2019
Cobalt can be employed as the metal, sometimes as powdered cobalt and sometimes in the form of cobalt wire, or as a solution of either cobaltous or cobaltic chloride. In this discussion, we will concentrate on the use of cobalt wire as the epileptogenic agent (the paper by Hattori et al.17 describes a method utilizing cobalt chloride if one is interested). The most recent purchase of cobalt wire that this author made was from Aldrich Chemical Company, Inc., St. Louis, MO. For rats, the best size for producing seizures is wire 1.0 mm in diameter. For some purposes, one may choose cobalt that is thinner; wire 10 mil in diameter is available and will also produce seizures.
Effects on white blood cell counts and the NLRP3 inflammasome due to dust and cobalt exposure in the hard metal industry
Published in Biomarkers, 2022
Alexander Hedbrant, Daniel Eklund, Lena Andersson, Ing-Liss Bryngelsson, Alexander Persson, Håkan Westberg, Eva Särndahl
Cobalt is used in a variety of applications, including the production of hard metals and in lithium-ion batteries. With increasing and innovative use of cobalt globally, new occupations at risk of exposure are introduced, and further understanding of the biological effects of cobalt is needed to ensure its safe use and handling, as exposure has been found to cause adverse health effects (Leyssens et al. 2017). Occupational exposure to cobalt per se has been associated with adverse health effects that include allergic dermatitis, asthma, hard metal lung disease, and possible effects on myocardial tissue (Linna et al. 2004, Leyssens et al. 2017). Cobalt metal with tungsten carbide is furthermore classified as probably carcinogenic by the IARC (IARC 2006). Therefore, monitoring levels of cobalt and risk reduction of exposure is well established within the hard metal industry, where cobalt is used as a binder together with tungsten carbide to produce the hard metal used mainly for cutting tools.
Metal-on-metal hip prosthesis in pregnancy: overall toxicological risks
Published in Journal of Obstetrics and Gynaecology, 2021
Andrea Giampreti, Georgios Eleftheriou, Giuseppe Bacis
Possible metal release from hip metal prosthetic implants and subsequent potential toxic effects on the human body have raised concerns among the scientific community. Particularly, wear and corrosion of cobalt/chromium (Co/Cr) containing hip prosthetics with subsequent Co/Cr release have resulted in the last decade in product recalls, public alerts and the need for clinicians, health authorities and scientific societies to evaluate and follow up metal-on-metal hip-implanted patients for local and systemic toxic effects. There is little data involving the clinical effects of metal ion levels in pregnant metal hip implanted women. Successful pregnancies have been reported with high maternal, cord and infant blood levels for Co/Cr. Only one case of spontaneous abortion has been described. Metal hip replacement does not seem to increase the reproductive risk, but no conclusive data are available; the experience is still limited and further investigations are required in order to evaluate pregnancies clinical outcome and offspring physical and mental development. Surgeons and women of childbearing age should be aware of when selecting a joint replacement; if possible, alternative implant composition could be considered too.
Effect of gap outside contact area on lubrication of metal-on-Metal total hip replacement
Published in Computer Methods in Biomechanics and Biomedical Engineering, 2020
Ali A. Al-Saffar, Sam L. Evans
A typical MOM cobalt chromium, CoCr, alloy (Elkins et al. 2012) of the Total hip replacement which was taken as the material to be used in this research. A ball-in-socket MOM contacts were analysed using the Abaqus software package to simulate the dry contact between the acetabular cup and the femoral head. The two contacting surfaces of a ball-in-socket model are assumed to be smooth and steady state conditions are adopted. The results of the dry contact FEA were compared with the Hertzian theory analysis. The gap outside the contact area zone from the Hertzian theory will be calculated and compared with the gap obtained from the FEA. From the principles of the Hertzian theory, when the principal radii of relative curvature of the contacting bodies are equal then the contact area shape is circular. Consequently, a circular point contact will be adopted due to the symmetry of the geometry used.