Chelation individual chelating agents

Another condition involving ceruloplasmin is aceru-loplasminemia. in this genetic disorder, levels of ceruloplasmin are very low and consequently its ferroxidase activity is markedly deficient. This leads to failure of release of iron from cells, and iron accumulates in certain brain cells, hepatocytes, and pancreatic islet cells. Affected individuals show severe neurologic signs and have diabetes mellitus. Use of a chelating agent or administration of plasma or ceruloplasmin concentrate may be beneficial. 

The heavy metals copper, manganese, cobalt and zinc were omitted individually and in combination from MS and B5 media to determine the effect on antibody stability in solution [63]. When IgG, antibody was added to these modified media in experiments similar to the one represented in Figure 2.2, only the B5 medium without Mn showed a significant improvement in antibody retention relative to normal culture media. Nevertheless, protein losses were considerable as only about 30% of the added antibody could be detected in the Mn-free medium after about 5 h. The beneficial effect of removing Mn was lost when all four heavy metals, Cu, Mn, Co and Zn, were omitted simultaneously. The reason for these results is unclear. Addition of the metal chelating agent ethylenediaminetetraacetate (EDTA) had a negligible effect on antibody retention in both MS and B5 media [63]. 

Eluants.—Citric acid buffered with ammonium citrate is the first eluant to be used in the separation of rare earths by ion exchange process. It is also the most extensively [85—89] investigated eluant. At low pH the individual rare earths move down the column at different rates. A plot of volume of eluted portion vs. concentration shows typical bell-shaped curves (Fig. 2) with widely spaced maxima characteristic of elution chromatography, although the system makes use of a chelating agent. 

Table 1. Cross referencing of applications of chelating agents with chemical groupings or individual chelating agents...

Applications Chemical Grouping or Individual Chelating Agents... 

D-Penicillamine, a chelating agent that can be administered orally, is currently used to chelate lead on an experimental basis. Individuals who are allergic to penicillin may experience adverse reactions to this agent toxic effects have been reported in as many as 20% of the patients treated with this compound. 

Alternatively, a chelating agent such as EDTA (ethylenediamine tetraacetic acid), may be added at a concentration of approximately 0.01%, to form a soluble complex with these metals. When two or more microorganisms are placed in a medium, their combined metabolic activities may differ, either quantitatively or qualitatively, from the sum of the activities of the individual members growing in isolation in the same medium. Such phenomena result from nutritional or metabolic interactions and are collectively termed synergistic effects.0 1... 

Citric, ascorbic, and phosphoric acids are added to chelate the trace metals, particularly copper and iron, to retard the initiation step. Mixtures of antioxidants and chelating agents act synergistically, that is, the combination is more effective than the sum of the individual compounds. A commercial mixture recommended by the American Meat Institute and sold as Tenox or Sustane is 20% BHA, 6% propyl gallate, and 4% citric acid in propylene glycol. The propylene glycol is added to solubilize the citric acid in the oil. 

ECD electron capture detector Ecogenetics genetic predisposition for an individual reaction to environmental factors edema pathological accumulation of fluid in the tissue spaces (also known as dropsy) EDS energy dispersive spectrometry EDTA ethyl enediamine tetraacetic acid (chelating agent) used in analysis and therapy... 

Because the onset of lead poisoning usually is insidious, it often is desirable to estimate the body burden of lead in individuals who are exposed to an environment that is contaminated with the metal. In the past, the edetate calcium disodium (CaNaJlDTA) provocation test was used to determine whether there is an increased body burden of lead in those for whom exposure occurred much earlier. The provocation test is performed by intravenous administration of a single dose of CaNa DTA (50 mg/kg) followed by collection of urine for 8 hours. The test is positive for children when the lead excretion ratio (pg of lead excreted in the urine per mg of CaNa DTA administered) is >0.6 it also may be useful for therapeutic chelation in children with blood levels of 25 5 pg/dL. This test is not used in symptomatic patients or in those whose concentration of lead in blood is >45 pg/dL because these patients require the proper therapeutic regimen with chelating agents (see below). 

In mass-transfer-controlled systems in which extensive complexing or association takes place in the bulk phases, a proper mass transfer model must account for transport of all species. Otherwise, the transport model will not be consistent with a chemical model of phase equilibrium. For example. Fig. 8.4-4 indicates schematically the species concentration profiles established during the extraction of copper from ammonia-ammonium sulfate solution by a chelating agent such as LIX. In most such cases the reversible homogeneous reactions, like copper complexation by ammonia, will be fast and locally equilibrated. The method of Olandei can be applied in this case to compute individual species profiles and concentrations at the interfiice for use in an equilibrium or rate equation. This has been done in the rate analyses of several of the chloride and ammonia systems cited above. ... 

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