Chromium blood

There appears to be a chromium pool in individuals who are not chromium deficient (136). When there is an increase in level of cHculating insulin in response to a glucose load, an increase in circulating chromium occurs over a period of 0.5—2 h. This is foUowed by a decline and excretion of chromium in urine increases. Chromium deficiency is indicated when no increase or a small increase in blood chromium level or urine chromium occurs. 

Langard S, Gundersen N, Tsalev DL, et al. 1978. Whole blood chromium level and chromium excretion in the rat after zinc chromate inhalation. Acta Pharmacol Toxicol 42 142-149. 

Protein-Based Adhesives. Proteia-based adhesives are aormaHy used as stmctural adhesives they are all polyamino acids that are derived from blood, fish skin, caseia [9000-71 -9] soybeans, or animal hides, bones, and connective tissue (coUagen). Setting or cross-linking methods typically used are iasolubilization by means of hydrated lime and denaturation. Denaturation methods require energy which can come from heat, pressure, or radiation, as well as chemical denaturants such as carbon disulfide [75-15-0] or thiourea [62-56-6]. Complexiag salts such as those based upon cobalt, copper, or chromium have also been used. Formaldehyde and formaldehyde donors such as h exam ethyl en etetra am in e can be used to form cross-links. Removal of water from a proteia will also often denature the material. 

Chromium(III) Chemistry. The most characteristic reactions of Cr(III) in aqueous solution at >4 pH, eg, in the intestine and blood, and hydrolysis and olation (147). As a consequence, inorganic polymeric molecules form that probably are not able to diffuse through membranes. This may be prevented by ligands capable of competing for coordination sites on Cr(III) (see Coordination compounds) (147). Thus any large fraction of ingested Cr(III) should be absorbed. Chromium (ITT) in the form of GTF may be more efficiendy absorbed. 

It appears that chromium(III) is an essential trace element in mammalian metabolism and, together with insulin, is responsible for the clearance of glucose from the blood-stream. Tungsten too has been found to have a role in some enzymes converting CO2 into formic acid but, from the point of view of biological activity, the focus of interest in this group is unquestionably on molybdenum. 

Aqueous standard solutions are a source of certain difficulties In electrothermal atomic absorption spectrometry of trace metals In biological fluids The viscosities and surface tensions of aqueous standard solutions are substantially less than the viscosities and surface tensions of serum, blood and other proteln-contalnlng fluids These factors Introduce volumetric disparities In pipetting of standard solutions and body fluids, and also cause differences In penetration of these liquids Into porous graphite tubes or rods Preliminary treatment of porous graphite with xylene may help to minimize the differences of liquid penetration (53,67) A more satisfactory solution of this problem Is preparation of standards In aqueous solutions of metal-free dextran (50-60 g/llter), as first proposed by Pekarek et al ( ) for the standardization of serum chromium analyses This practice has been used successfully by the present author for standardization of analyses of serum nickel The standard solutions which are prepared In aqueous dextran resemble serum In regard to viscosity and surface tension Introduction of dextran-contalnlng standard solutions Is an Important contribution to electrothermal atomic absorption analysis of trace metals In body fluids. 

The weight-loss effects of chromium have not been proven. Chromium may be unsafe in high doses, especially when combined with picolinate. Specifically, chromium picolinate may cause headaches and mood disturbances. High doses may lead to blood and disorders of the liver and kidney, and may increase the risk of cancer. 

Among warm-blooded organisms, hexavalent chromium was fatal to dogs in 3 months at 100 mg/kg in their food and killed most mammalian experimental animals at injected doses of 1 to 5 mg Cr/kg body weight, but it had no measurable effect on chickens at dietary levels of 100 mg/kg over a 32-day period. Trivalent chromium compounds were generally less toxic than hexavalent chromium compounds, but significant differences may occur in uptake of anionic and cationic CL3 species, and this difference may affect survival. 

Laj, S., V.K. Jain, and S.K. Tandon. 1984. Comparative toxicity of trivalent and hexavalent chromium IV biochemical changes in blood and liver of rat. Jour. Environ. Biol. 5 29-35. 

Tandon, S.K., D.K. Saxena, J.S. Gaur, and S.V. Chandra. 1978. Comparative toxicity of trivalent and hexavalent chromium. Alterations in blood and liver. Environ. Res. 15 90-99. 

Feldman and co-workers117) described a procedure for determining as little as 10 ppb of chromium in serum. The normal level is 30 ppb. At least 2 ml of serum are digested or dry ashed and treated with not permanganate to oxidize chromium to chromium(VI). The chromium(VI) is extracted from 3M HC1 into 5 ml MIBK in the cold. This method has been used to measure chromium levels in studies relating this element to diabetes. Thousands of analyses have been performed. Devoto (198) dry ashed 10 ml of blood and extracted the chromium with 5 ml of 10 % tributyl phosphate in MIBK. Recently, Feldman 119) has determined... 

It is known that part of this process involves the 80-kDa blood serum protein transferrin that tightly binds and transports two ferric iron ions. Because the iron binding uses only 30% of transferrin s metal binding capacity, it has long been thought to bind and transfer other metal ions (including perhaps chromium) in vivo, although this has not been demonstrated by experiment. 

This reaction is accompanied by a visible colour change, as orange dichromate ions become green chromium(lll) ions. The concentration of alcohol in the blood is determined by measuring the intensity of the final colour. 

Chromiums most important radioisotope is chromium-51, which has a half-life of about 27 days. It is used as a radioisotope tracer to check the rate of blood fiowing in constricted arteries. 

R. H. Liebross and K. E. Wetterhan, In vivo formation of chromium(V) in chick embryo liver and red blood cells, Carcinogenesis, 13 (1992) 2113-2120. 

M. Branca, A. Dessi, H. Kozlowski, G. Micera, and M. V. Serra, In vitro interaction of mutagenic chromium(VI) with red blood cells, FEBS. Lett., 257 (1989) 52-54. 

Chromium coatings are applied on the surface of other metals for decorative purposes, to enhance resistance, and to lower the coefficient of friction. Radioactive chromium-51 is used as a tracer in the diagnosis of blood volume. 

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