Copper excess

Figure 7.4 Copper uptake and release in E. hirae. The extracellular reductase CorA reduces Cu2+ to Cu+ for uptake by CopA. In conditions of copper excess CopB functions as a copper exporter. (From Solioz and Stoyanov, 2003. Reproduced with permission from Blackwell Publishing Ltd.)...

Fig. 5. Copper homeostasis in Enterococcus hirae. Under copper-limiting conditions, copper is pumped into the cell by CopA. The CopZ copper chaperone picks up copper at this site of entry. Under physiological copper conditions, Zn(II)CopY binds to the promoter and represses transcription of the cop operon. Under conditions of copper excess, Cu-CopZ donates Cu(I) to CopY, which leads to the replacement of the Zn(II), loss of DNA-binding affinity, and ultimately synthesis of the operon products. Excess copper is secreted by the CopB efflux pump. The substrate for this pump may be a copper-glutathione (GSH) complex, rather than Cu-CopZ.

Oxidation. Oxidation of oils and fats is due to prolonged exposure to air. By virtue of the low polyunsaturated fatty acid content, palm oil is relatively more stable to oxidative deterioration than the polyunsaturated vegetable oils. However, in the presence of trace metals such as iron and copper, excessive oxidation at the olefin bonds of the oleic and linoleic acids can occur, resulting in rancidity. Highly oxidized crude palm oil is known to have poor bleachability and thus requires more bleaching earth and more severe refining conditions, and the final product will likely be of poor stability (44, 45, 68). 

Menkes disease (associated with copper deficiency) and Wilson s disease (associated with copper excess) (1,2), and its possible role in Alzheimer s disease (3), prion disease (4), and familial amyotrophic lateral sclerosis... 

In young swine, addition of 0.5% ascorbic acid to a diet containing a toxic amount of copper, 250 mg/kg of diet, reduced the anemia that was the toxic manifestation of copper excess, and reduced hepatic accumulation of copper (53). 

In strains that have the ability to produce both enzymes, the major controlling parameter for the expression of the two MM Os appears to be copper availability. Under conditions of copper excess, the pMMO predominates, whereas the sMMO predominates during copper limitation (10). These results have... 

Copper sulfate causes ulceration of the oral and esophageal mucosa, and an acute dose of 7-8 g is usually fatal. Copper intoxication has occurred when copper salts were used to treat extensive skin bums or when copper-containing tubing or dialysis membranes were used for hemodialysis. Pulmonary fibrosis has been described in vineyard workers exposed for many years to fungicidal sprays (e.g., Bordeaux mixture ) containing copper sulfate. About 33-50 mg of copper per year ( 100 /rg/d) dissolves from copper-containing intrauterine contraceptive devices. Part of this copper is lost in menstrual flow, but part is rapidly absorbed. Whether this is harmful is not known but it seems unlikely. Penicillamine is the drug of choice for treatment of copper excess. 

Congenital adrenal hyperplasia Congestive heart failure Chromosome disorders Chromosome mosaicism Chromosome translocation Copper excess Cri-du-chat syndrome Crouzon s syndrome Cushing s syndrome Cyanide poisoning Cystic fibrosis Diabetes insipidus Diabetes mellitus Dinitrophenol poisoning Diphtheria... 

They also have tried to explain copper state in the zeolite type catalysts used in the reduction reaction of NOx with hydrocarbons in the presence of a greater amount of oxygen in the reaction medium, therefore under distinctly oxidizing conditions. They evidenced the importance of copper excess in such catalysts (the level of copper ion exchange in ZSM-5 over 100%) and confirmed the literature data which show that copper is present on the surface of these catalysts under two forms (Cu2+, Cu+) [6, 9],... 

Poor workmanship and defective materials can increase corrosion. Water turbulence effects can be increased by poor workmanship, such as the failure to ream burrs from cut ends of copper pipe. This increases the turbulence at the joints and results in erosion of the copper. Excessive and corrosive flux used in soldered coppers joints results in pitting corrosion along the flux runs. Incomplete longitudinal welds in electric resistance welded (ERW) steel pipe result in concentration cell corrosion and rapid corrosion. 

Excess copper is the result of either excessive copper absorption or ineffective copper excretion. The most common diseases associated with copper excess are (1) Wilson s disease, a genetic disease resulting in mutations in the Wilson s disease P-type ATPase and excessive hepatocyte copper accumulation (2) renal disease, in patients on hemodialysis due to kidney failure when dialysate solutions become contaminated with excess copper and (3) biliary obstruction. Excessive use of copper supplements may also contribute to copper toxicity and is clinically manifested by severe anemia, nausea and vomiting, abdominal pain, and diarrhea. 

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