Determination of copper concentration in blood plasma and in ocular and cerebrospinal fluids using graphite furnace atomic absorption spectroscopy

Published values for the concentration of Cu in cerebrospinal and intraocular fluids cover a very wide range (0.016 to 1.0 microgram/ml) and include values which are several times higher than those which would be consistent with normal physiology. An atomic absorption spectrophotometer equipped with a graphite furnace was used to measure the Cu concentration in these fluids and in blood plasma of toads, rabbits, and cats. Under standard conditions, these fluids yielded high background absorbance and only fractional recovery of added Cu. Parameters were therefore established which eliminated both the high background and the matrix interference and allowed the determination of Cu in 10-microliters aliquots of diluted blood plasma and undiluted cerebrospinal and ocular fluid samples. Under these conditions the Cu measured in the ocular (0.011 to 0.032 microgram/ml) and cerebrospinal fluids (0.033 to 0.050 microgram/ml) of these three species was lower than most previously reported values and only a small fraction (1-3%) of the concentration of Cu in the plasma of the same animals (0.85 to 1.22 micrograms/ml).     

EFFECT OF COPPER ON GROWTH,SILICIC ACID UPTAKE AND SOLUBLE POOLS OF SILICIC ACID IN THE MARINE DIATOM,THALASSIOSIRA WEISFLOGII (BACILLARIOPHYCEAE)1

The toxicity of Cu to Thalassiosira weissflogii (Grunow) was investigated, focusing on the internal soluble pool of silicic acid. Silicic acid uptake and growth rates were found to be functions of both the cupric ion activity and the concentration of silicic acid in the growth medium. The soluble pool of Si per cell depended on the balance between the uptake rate and the division rate. The soluble pool in non-dividing cultures reflected simply the uptake rate (and inhibition by copper of the uptake rate), but in dividing cultures the soluble pools had complex patterns with time depending on uptake rates and timing of division. Intracellular soluble pools of silicic acid are a good indicator for the relative inhibition of uptake and growth processes.     

Variation in the relationship between nitrogen fixation, leghemoglobin, nodule numbers and plant biomass in alfalfa (Medicago sativa) caused by treatment with arsenate, heavy metals and fluoride

Potential relationships between alfalfa ( Medicago sativa L. cv. Vernal) acetylene reduction activity (ARA) and leghemoglobin content, nodule numbers, shoot biomass, root biomass, or total plant biomass were estimated using linear regression analysis after treatment with a range of concentrations of arsenate, Cd²⁺, Cu²⁺, Pb²⁺, Zn²⁺, and F^–. There were highly significant positive linear regressions between ARA and all the other plant values in the control plants, but this linear relationship was significantly altered between ARA and one or more of the other parameters in all treatments. There was also evidence for an alteration of the slope in some of the treatments when compared to control treatments even though a linear model was still applicable.     

Zinc and copper in fish from natural waters and rearing ponds in Northern Italy

Zinc and copper were detected in several tissues of fresh and saltwater fish. Liver concentrations varied widely, with respect to the storage and detoxication functions of the organ. In muscular tissues the two metals are linked to aerobic metabolism being higher in the heart and lower in the white muscle. High levels of zinc were found in the female gonad, while in the brain zinc has been shown to be more constant and possibly regulated better than copper. In sea bass supplemented with artificial diets no correlation was found between the metal content in the diet and that of the tissue. In goldfish attempts using gel filtration to isolate specific metal binding proteins of low molecular weight gave negative results, the metals were mostly bound to ligands excluded from the gel.     

Effects of metals on enzyme activity in plants

Abstract. Uptake of phytotoxic amounts of metal by higher plants or algae can result in inhibition of several enzymes, and in increase in activity (= induction) of others. Two mechanisms of enzyme inhibition predominate: (1) binding of the metal to sulphydryl groups, involved in the catalytic actionor structural integrity of enzymes, and (2) deficiency of an essential metal in metalloproteins or metal-protein complexes, eventually combined with substitution of the toxic metal for the deficient element. Metal accumulation in the cellular compartment of the enzyme is a prerequisite for enzyme inhibition in vivo. The induction of some enzymes is considered to play a significant role in the stress metabolism, induced by metal phytotoxicity. Peroxidase induction is likely to be related to oxidative reactions at the biomembrane; several enzymes of the intermediary metabolism might be stimulated to compensate for metal-sensitive photosynthetic reactions. The induction of enzymes and metal-specific changes in isoperoxidase pattern can be used as diagnostic criteria to evaluate the phytotoxicity of soils, contaminated by several metals. Lines for future research on metal phytotoxicity are proposed, involving the study of inhibition and induction of enzymes at the different cell membranes (especially the plasmamembrane) in vivo.     

Effects of copper aspirinate and aspirin on tissue copper,zinc, and iron concentrations following chronic oral treatment in the adjuvant arthritic rat

Concentrations of copper, zinc, and iron were analyzed and compared in a number of tissues of adjuvant arthritic rats following 22 d of chronic treatment (per os) with either vehicle, aspirin or copper aspirinate, at doses of 100 mg/kg, 200 mg/kg, or 400 mg/kg. Such chronic treatment resulted in a negative balance in copper, zinc, and iron in many tissues. Among the tissues examined, liver and kidney exhibited the greatest changes in metal concentrations; brain and skeletal muscle exhibited the least. Arthritis-induced changes in the concentrations of all three metals in the liver were reversed upon treatment with aspirin. Treatment with copper aspirinate, on the other hand, resulted in an extremely high accumulation of copper in the liver. Arthritis-induced changes in copper, zinc, and iron concentrations in the pancreas and copper concentration in the plasma were generally not reversed upon treatment with either aspirin or copper aspirinate. Among the three metals examined, the degree of change observed as a result of drug treatments was greatest for iron and least for zinc. Finally, it appeared that the effects of aspirin and copper aspirinate on tissue metal concentrations were independent of the antiarthritic effects of these compounds.     

DNA Single Strand Breakage by H2O2 and Ferric or Cupric Ions: Its Modulation by Histidine

The role of histidine on DNA breakage induced by hydrogen peroxide (H₂O₂) and ferric ions or by H₂O₂ and cupric ions was studied on purified DNA. L-histidine slightly reduced DNA breakage by H₂O₂ and Fe³⁺ but greatly inhibited DNA breakage by H₂O₂ and Cu²⁺. However, only when histidine was present, the addition of EDTA to H₂O₂ and Fe³⁺ exhibited a bimodal dose response curve depending on the chelator metal ratio. The enhancing effect of histidine on the rate of DNA degradation by H₂O₂ was maximal at a chelator metal ratio between 0.2 and 0.5, and was specific for iron. When D-histidine replaced L-histidine, the same pattern of EDTA dose response curve was observed. Superoxide dismutase greatly inhibited the rate of DNA degradation induced by H₂O₂, Fe³⁺, EDTA and L-histidine involving the superoxide radical.

These studies suggest that the enhancing effect of histidine on the rate of DNA degradation by H₂O₂ and Fe³⁺ is mediated by an oxidant which could be a ferrous-dioxygen-ferric chelate complex or a chelate-ferryl ion.     

A high resolution PIXE measurement for blood plasma ultrafiltrate

A new technique for investigation of elemental concentrations in subfractions of blood plasma is presented. The method is composed of the ultrafiltration of plasma in the presence of ethylenediaminetetraacetic acid (EDTA) and the measurement of the elemental composition by proton-induced X-ray emission (PIXE). The blood samples were collected from both healthy persons and patients suffering from breast cancer. The main emphasis in this study was on the determination of loosely bound copper (Cu) in plasma subfractions containing substances with molecular mass under 10,000, but zinc (Zn) and iron (Fe) contents of these fractions were also determined. The detection limits obtained with this method for Cu, Zn and Fe were ≈10 ppb (wet wt).     

A case-control study on selenium,zinc, and copper in plasma and hair of subjects affected by breast and lung cancer

The purpose of our study was to investigate the relationship between plasma and hair levels of Se, Zn, and Cu, and cancer. We selected a total of 66 patients affected by either breast (38) or lung (28) cancer. They entered into the study at the onset of disease, and before any chemical or radiotherapy. Controls were randomly selected among healthy people and were matched for sex, age, smoking habits, and residence. In the group of breast cancer, a significant decrease in hair Se was found compared to controls (p<0.01), whereas plasma Se was only slightly decreased. No difference between cases and controls was detected in both hair and plasma levels of Zn and Cu. Subjects who developed lung cancer were significantly lower in hair Zn (p<0.05) and Cu (p<0.01) than controls, whereas there was no difference with regard to Se. In addition, plasma Cu of these patients was increased as compared to controls.