Classification Term: 4155
Homogeneous metalloid compounds (ontology term: CHEMONTID:0000431)
Inorganic compounds containing only metal atoms,with the largest atom being a metalloid atom." []
found 6 associated metabolites at class metabolite taxonomy ontology rank level.
Ancestor: Homogeneous metal compounds
Child Taxonomies: There is no child term of current ontology term.
Arsenic
Arsenic(As) is a ubiquitous metalloid found in several forms in food and the environment, such as the soil, air and water. Physiologically, it exists as an ion in the body. The predominant form is inorganic arsenic in drinking water, which is both highly toxic and carcinogenic and rapidly bioavailable. Arsenic is currently one of the most important environmental global contaminants and toxicants, particularly in the developing countries. For decades, very large populations have been and are currently still exposed to inorganic Arsenic through geogenically contaminated drinking water. An increased incidence of disease mediated by this toxicant is the consequence of long-term exposure. In humans chronic ingestion of inorganic arsenic (> 500 mg/L As) has been associated with cardiovascular, nervous, hepatic and renal diseases and diabetes mellitus as well as cancer of the skin, bladder, lung, liver and prostate. Contrary to the earlier view that methylated compounds are innocuous, the methylated metabolites are now recognized to be both toxic and carcinogenic, possibly due to genotoxicity, inhibition of antioxidative enzyme functions, or other mechanisms. Arsenic inhibits indirectly sulfhydryl containing enzymes and interferes with cellular metabolism. Effects involve such phenomena as cytotoxicity, genotoxicity and inhibition of enzymes with antioxidant function. These are all related to nutritional factors directly or indirectly. Nutritional studies both in experimental and epidemiological studies provide convincing evidence that nutritional intervention, including chemoprevention, offers a pragmatic approach to mitigate the health effects of arsenic exposure, particularly cancer, in the relatively resource-poor developing countries. Nutritional intervention, especially with micronutrients, many of which are antioxidants and share the same pathway with Arsenic , appears a host defence against the health effects of arsenic contamination in developing countries and should be embraced as it is pragmatic and inexpensive. (PMID: 17477765, 17179408). Arsenic(As) is a ubiquitous metalloid found in several forms in food and the environment, such as the soil, air and water. Physiologically, it exists as an ion in the body. The predominant form is inorganic arsenic in drinking water, which is both highly toxic and carcinogenic and rapidly bioavailable. Arsenic is currently one of the most important environmental global contaminants and toxicants, particularly in the developing countries. For decades, very large populations have been and are currently still exposed to inorganic Arsenic through geogenically contaminated drinking water. An increased incidence of disease mediated by this toxicant is the consequence of long-term exposure. In humans chronic ingestion of inorganic arsenic (> 500 mg/L As) has been associated with cardiovascular, nervous, hepatic and renal diseases and diabetes mellitus as well as cancer of the skin, bladder, lung, liver and prostate. Contrary to the earlier view that methylated compounds are innocuous, the methylated metabolites are now recognized to be both toxic and carcinogenic, possibly due to genotoxicity, inhibition of antioxidative enzyme functions, or other mechanisms. Arsenic inhibits indirectly sulfhydryl containing enzymes and interferes with cellular metabolism. Effects involve such phenomena as cytotoxicity, genotoxicity and inhibition of enzymes with antioxidant function. These are all related to nutritional factors directly or indirectly. Nutritional studies both in experimental and epidemiological studies provide convincing evidence that nutritional intervention, including chemoprevention, offers a pragmatic approach to mitigate the health effects of arsenic exposure, particularly cancer, in the relatively resource-poor developing countries. Nutritional intervention, especially with micronutrients, many of which are antioxidants and share the same pathway with Arsenic , appears a host defence against the health effects of arsenic contamination in developing countries and should be embraced as it is pragmatic and inexpensive. (PMID: 17477765, 17179408)
Germanium
Germanium is a chemical element with the symbol Ge and atomic number 32. It is a lustrous, hard, grayish-white metalloid in the carbon group, chemically similar to its group neighbors tin and silicon. Germanium has five naturally occurring isotopes ranging in atomic mass number from 70 to 76. It forms a large number of organometallic compounds, including tetraethylgermane and isobutylgermane. Germanium is found in many foods, some of which are white cabbage, soft-necked garlic, garlic, and tea. Germanium is not an essential element. Physiologically, it exists as an ion in the body. Its acute toxicity is low. Germanium-containing dietary supplements became popular in the 1970s in Japan and later in other countries, as elixirs for certain diseases (e.g., cancer and AIDS). However, at least 31 reported human cases linked prolonged intake of germanium products with renal failure and even death.
Silicon
Silicon (Si) is the second most abundant element in the Earths crust and although there has been interest in the biological role of Si since the beginning of the century, it is only in the last three decades that it has been suggested as an essential trace element. Si may have a role in a number of areas of human physiology and metabolism, especially bone and connective tissue formation, but possibly also gene expression and cardiovascular health. Si is rarely found in its elemental form as it readily reacts with atmospheric O2 and water to produce silicates. Physiologically, it exists as an ion in the body. These vary in composition from simple soluble orthosilicic acid and oligomers through to less soluble colloids and gels, and insoluble solid-phase silicates. The latter constitute the vast majority of environmental silicates (for example, soil minerals), although natural waters contain soluble silicates (mostly orthosilicic acid) generally at 1 to 20 mg/l. Orthosilicic acid is the most readily absorbed form of Si and silicate in man. Silicon plays an important role in bone mineralization and formation and is therefore incorporated into a wide variety of medical implants and bone grafts used today. Low bone mass (osteoporosis) is a silent epidemic of the 21st century, which presently in the UK results in over 200,000 fractures annually at a cost of over one billion pounds. Figures are set to increase worldwide. Understanding the factors which affect bone metabolism is thus of primary importance in order to establish preventative measures or treatments for this condition. Nutrition is an important determinant of bone health, but the effects of the individual nutrients and minerals, other than calcium, is little understood. Accumulating evidence over the last 30 years strongly suggest that dietary silicon is beneficial to bone and connective tissue health and we recently reported strong positive associations between dietary Si intake and bone mineral density in US and UK cohorts. The exact biological role(s) of silicon in bone health is still not clear, although a number of possible mechanisms have been suggested, including the synthesis of collagen and/or its stabilization, and matrix mineralization. The field of bioorganosilicon chemistry, which sprung up in the 1970s to exploit the opportunities of silicon for drug design, is currently being developed into a practical and commercial enterprise. Some of the fundamental differences between carbon and silicon can lead to marked alterations in the physicochemical and biological properties of the silicon-containing analogues and the resulting benefits can be exploited in the drug design process. Recent evidence confirms the fundamental involvement of the human immune system in the reaction to implantation of silicone based medical devices. An as yet to be particularized epitope of many complex substances sharing siloxane structures is presented through the MHC-II apparatus with development and retention of T cell memory. This memory can be tested for in practical terms using one or more forms of silica, which links the immuno-histopathology and autoimmune attributes of silicosis with those of siliconosis. The lesions of siliconosis are typical of those for persistent antigens and delayed, cell mediated hypersensitivity. The basic descriptive pathology of the reaction to silicone has been known since soon after introduction of silicones in medical procedures, with the exception of some details related to the more recent discoveries on the role of cytokines in the immunopathic process. The clinical consequences of siliconosis are common and can be severe in some individuals implanted with silicone devices. (PMID: 16277785, 16632368, 17435952, 12821303, 12951816, 9951648). Silicon (Si) is the second most abundant element in the Earths crust and although there has been interest in the biological role of Si since the beginning of the century, it is only in the last three decades that it has been suggested as an essential trace element. Si may have a role in a number of areas of human physiology and metabolism, especially bone and connective tissue formation, but possibly also gene expression and cardiovascular health. Si is rarely found in its elemental form as it readily reacts with atmospheric O2 and water to produce silicates. Physiologically, it exists as an ion in the body. ATC code: A03AX13
Tellurium
Te (129.906229)
Tellurium is a trace element that belongs chemically to the VIa group in the periodic chemical table that has the symbol Te and atomic number 52. Tellurium is a brittle silver-white metalloid which looks like tin, and is related to selenium and sulfur. Physiologically, it exists as an ion in the body. The ingestion of tellurium compounds has been known to be associated with a garlic-like odor of the breath, thus indicating that tellurium is absorbed by the gut, metabolized by tissues, and excreted through routes other than the feces. Little is known about the Te biological activity, particularly with respect to potential chemical interactions with Se-containing components in the organism. Tellurium is a non-competitive inhibitor of squalene epoxidase and has been associated with neuropathy. Late fetal stages of prenatal development appeared uniquely sensitive to organic tellurium exposure. All tellurium compounds are highly toxic. (PMID: 17873396, 15596254, 10048717). Tellurium is a chemical element that has the symbol Te and atomic number 52. A brittle silver-white metalloid which looks similar to tin, tellurium is chemically related to selenium and sulfur. Tellurium is found in many foods, some of which are romaine lettuce, cucumber, orange bell pepper, and green zucchini.
Boron
Boron (pronounced /?b?r?n/) is the chemical element with atomic number 5 and the chemical symbol B. Boron is a trivalent metalloid element which occurs abundantly in the evaporite ores borax and ulexite.; Boron is a part of neodymium magnet (Nd2Fe14B), which is the strongest type of permanent magnet. It is found in all kinds of domestic and professional electromechanical and electronic devices, such as magnetic resonance imaging (MRI), various motors and actuators, computer HDDs, CD and DVD players, mobile phones, timer switches, speakers, etc.; Boron is a relatively rare element in the Earths crust, representing only 0.001\\%. The worldwide commercial borate deposits are estimated as 10 million tonnes. Turkey and the United States are the worlds largest producers of boron. Turkey has almost 72\\% of the world?s boron reserves. Boron does not appear on Earth in elemental form but is found combined in borax, boric acid, colemanite, kernite, ulexite and borates. Boric acid is sometimes found in volcanic spring waters. Ulexite is a borate mineral; it is a fibrous crystal where individual fibers can guide light like optical fibers.; Boron is an essential plant nutrient. Whereas lack of boron results in boron deficiency disorder, high soil concentrations of boron may also be toxic to plants. As an ultratrace element, boron is necessary for the optimal health of rats and presumably other mammals, though its physiological role in animals is not yet fully understood.; Boron is an important technological dopant for such important semiconductors as silicon, germanium and silicon carbide. Having one less valence electron than the host atom, it donates a hole resulting in p-type conductivity. Traditional method of introducing boron into semiconductors is via its atomic diffusion at high temperatures. This process uses either solid (B2O3), liquid (BBr3) or gaseous boron sources (B2H6 or BF3). However, after 1970s, it was mostly replaced by ion implantation, which relies mostly on BF3 as a boron source. Boron trichloride gas is also an important chemical in semiconductor industry, however not for doping but rather for plasma etching of metals and their oxides.; Boron is similar to carbon in its capability to form stable covalently bonded molecular networks. Even nominally disordered (amorphous) boron contains regular boron icosahedra which are, however, bonded randomly to each other without long-range order. Crystalline boron is a very hard, black material with a high melting point of above 2000 °C. It exists in four major polymorphs: ?, ?, ? and T. Whereas ?, ? and T phases are based on B12 icosahedra, the ?-phase can be described as a rocksalt-type arrangement of the icosahedra and B2 atomic pairs. It can be produced by compressing other boron phases to 12-20 GPa and heating to 1500-1800 °C; it remains stable after releasing the temperature and pressure. The T phase is produced at similar pressures, but higher temperatures of 1800-2200 °C. As to the ? and ? phases, they might both coexist at ambient conditions with the ? phase being more stable. Compressing boron above 160 GPa produces a boron phase with an as yet unknown structure, and this phase is a superconductor at temperatures 6-12 K.; Boron may be an essential nutrient for animals and humans. Physiologically, this metal/element exists as an ion in the body. Dietary boron influences the activity of many metabolic enzymes, as well as the metabolism of steroid hormones and several micronutrients, including calcium, magnesium, and vitamin D. Boron may also play a role in improving arthritis, plasma lipid profiles, and brain function.; Cosmic radiation will produce secondary neutrons if it hits spacecraft structures; and neutrons cause fission in 10B if it is present in the spacecrafts semiconductors, producing a gamma ray, an alpha particle, and a lithium ion. The resultant fission products may then dump charge into nearby semiconductor chip structures, causing data loss (bit flipping, or... Boron may be an essential nutrient for animals and humans. Physiologically, this metal/element exists as an ion in the body. Dietary boron influences the activity of many metabolic enzymes, as well as the metabolism of steroid hormones and several micronutrients, including calcium, magnesium, and vitamin D. Boron may also play a role in improving arthritis, plasma lipid profiles, and brain function.
Antimony
Sb (120.903824)
Antimony metal and many of its compounds have been known since ancient times, and its toxicity has periodically been a matter of comment. Antimony (stibium) is an element and a metalloid, with atomic number 51 and atomic weight 121.75. It is in Group Va of the Periodic Table along with arsenic, bismuth, nitrogen and phosphorus. Contact with antimony occurs in a variety of ways, and as it is a common element in the surface of the earth it may accompany exposures to many different materials. Antimony has been identified in at least 114 different ores, and has even been found in meteorites. A recurrent problem in assessing its toxicity industrially is that arsenic and lead are often found with it, and other toxic materials, for example sulfur dioxide, may also be produced in the course of the process, and separation of exposures may be difficult or impossible. Contact with antimony has also occurred from is use as a medicinal substance, from natural exposures, and from domestic sources. Antimony has been a constituent not only of printing-metal but also of lead acid batteries, pigments, an opacifier under glazes and enamels (the white oxide), and in the present day it has been used widely as a flame retardant in fabrics and in brake linings of motor cars. Large scale industrial production, largely of antimony oxide, began in the early 19th century.; Physiologically, this metal/element exists as an ion in the body. The toxicology of antimony and its compounds is known from three sources: its medicinal use over centuries, studies of process workers in more recent times, and more recent still, studies of its presence in modern city environments and in domestic environments. Gross exposure to antimony compounds over long periods, usually the sulfide (SbS3) or the oxide (Sb2O3) has occurred in antimony miners and in antimony process workers. There have been relatively few of these, and few studies of possible symptoms have been made. Antimony sulfide imported from, at different times, China, South Africa, and South America was processed in the North-East of England from about 1870 to 2003. The process workers in North-East England have been studied at different times, notably by Sir Thomas Oliver in 1933, and by the Newcastle upon Tyne University Department of Occupational Medicine on later occasions. Studies which have been made of the working environment, and in particular of the risk of lung cancer in process workers, have underlined the high levels of exposure to antimony compounds and to other toxic materials. However, the working conditions in antimony processing have improved markedly over the last 30 years, and the workforce had been much reduced in numbers following automation of the process. Prior to the cessation of the industry in the UK it had become a white coat operation with relatively few people exposed to high concentrations of antimony. Antimony, which is normally present in domestic environments, has also been studied as a possible cause of cot death syndrome (SIDS) but extensive investigations have not confirmed this. The full importance of environmental antimony has still to be determined, and evidence of specific effects has not yet been presented. (PMID: 16307078). Antimony metal and many of its compounds have been known since ancient times, and its toxicity has periodically been a matter of comment. Antimony (stibium) is an element and a metalloid, with atomic number 51 and atomic weight 121.75. It is in Group Va of the Periodic Table along with arsenic, bismuth, nitrogen and phosphorus. Contact with antimony occurs in a variety of ways, and as it is a common element in the surface of the earth it may accompany exposures to many different materials. Antimony has been identified in at least 114 different ores, and has even been found in meteorites. A recurrent problem in assessing its toxicity industrially is that arsenic and lead are often found with it, and other toxic materials, for example sulfur dioxide, may also be produced in the course of the process, and separation of exposures may be difficult or impossible. Contact with antimony has also occurred from is use as a medicinal substance, from natural exposures, and from domestic sources. Antimony has been a constituent not only of printing-metal but also of lead acid batteries, pigments, an opacifier under glazes and enamels (the white oxide), and in the present day it has been used widely as a flame retardant in fabrics and in brake linings of motor cars. Large scale industrial production, largely of antimony oxide, began in the early 19th century. Physiologically, this metal/element exists as an ion in the body. The toxicology of antimony and its compounds is known from three sources: its medicinal use over centuries, studies of process workers in more recent times, and more recent still, studies of its presence in modern city environments and in domestic environments. Gross exposure to antimony compounds over long periods, usually the sulfide (SbS3) or the oxide (Sb2O3) has occurred in antimony miners and in antimony process workers. There have been relatively few of these, and few studies of possible symptoms have been made. Antimony sulfide imported from, at different times, China, South Africa, and South America was processed in the North-East of England from about 1870 to 2003. The process workers in North-East England have been studied at different times, notably by Sir Thomas Oliver in 1933, and by the Newcastle upon Tyne University Department of Occupational Medicine on later occasions. Studies which have been made of the working environment, and in particular of the risk of lung cancer in process workers, have underlined the high levels of exposure to antimony compounds and to other toxic materials. However, the working conditions in antimony processing have improved markedly over the last 30 years, and the workforce had been much reduced in numbers following automation of the process. Prior to the cessation of the industry in the UK it had become a white coat operation with relatively few people exposed to high concentrations of antimony. Antimony, which is normally present in domestic environments, has also been studied as a possible cause of cot death syndrome (SIDS) but extensive investigations have not confirmed this. The full importance of environmental antimony has still to be determined, and evidence of specific effects has not yet been presented. (PMID: 16307078).