PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “Copper”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 307 records · Page 17Linked to original sources

The amyloid precursor protein of Alzheimer's disease in the reduction of copper(II) to copper(I)

The transition metal ion copper(II) has a critical role in chronic neurologic diseases. The amyloid precursor protein (APP) of Alzheimer's disease or a synthetic peptide representing its copper-binding site reduced bound copper(II) to copper(I). This copper ion-mediated redox reaction led to disulfide bond formation in APP, which indicated that free sulfhydryl groups of APP were involved. Neither superoxide nor hydrogen peroxide had an effect on the kinetics of copper(II) reduction. The reduction of copper(II) to copper(I) by APP involves an electron-transfer reaction and could enhance the production of hydroxyl radicals, which could then attack nearby sites. Thus, copper-mediated toxicity may contribute to neurodegeneration in Alzheimer's disease.

Alzheimer Disease↗

[The dynamic state of the concentrations of copper and histidine, and the complex effects of histidine and copper on the formation of lipid peroxidation in sera of undernourished young women].

OBJECTIVES: First, we observed that copper and histidine levels were increased in the sera of undernourished women. The objective of this study was to clarify the reason for the increase in copper and histidine. Furthermore, we tried to determine the compound(s) to which the increased copper was binding, and examined the effect of the increased copper and histidine on lipid peroxidation. METHODS: We investigated young women's diets and took blood samples, and the contents of histidine in the sera were determined by HPLC. The contents of copper were determined by flameless atomic absorption spectroscopy. The subjects were classified into three groups according to the concentration of histidine in the sera. The contents of copper and lipid peroxide in the sera were compared among the high histidine group and the other groups. We also examined the ability of the complexes to prevent LDL oxidation induced by copper, using an in vitro assay. RESULTS: The contents of lipid peroxide were lower in the high histidine group than in the other groups. Furthermore, the complexes of histidine and copper inhibited the formation of peroxidized lipids in an in vitro assay. CONCLUSIONS: These results indicate that histidine masks copper, reducing oxidation reaction. They also suggest that the complexes are suited for plasma antioxidation, preventing oxidative modification of lipids in the sera of undernourished women. The increased histidine appeared to be an effective trap for active oxygen.

Adult↗

Development of copper deficiency in rats fed fructose or starch: weekly measurements of copper indices in blood.

Copper deficiency was induced in weanling rats fed diets whose sole source of carbohydrates was starch or fructose for 7 weeks. Conventional parameters of copper status, plasma copper concentrations, ceruloplasmin activity, and erythrocyte superoxide dismutase (SOD) activity were longitudinally monitored weekly to follow the development of the deficiency and to correlate these indices with the degree of severity of the deficiency. Although 30% of the rats fed a copper-deficient fructose diet died and no deaths occurred in rats fed the copper-deficient starch diet, plasma copper, ceruloplasmin, and SOD activities were reduced to a similar extent in all rats fed copper-deficient diets regardless of the type of dietary carbohydrate. Thus, none of the indices used accurately reflected the greater degree of deficiency or mortality in rats fed the fructose diet deficient in copper. The results of the present study underscore the need for more sensitive tests or alternative parameters to assess copper status in living animals.

Animals↗

Digitonin resistance of liver mitochondria isolated from copper-deficient and copper-loaded rats.

Liver mitochondria of copper-deficient and copper-loaded rats are with changed composition, ultrastructure and functions. The aim of the present work is to study the digitonin resistance of these mitochondria as an indicator for the changes in the membranes. Copper deficiency and copper loading are achieved by eliminating resp. by adding copper to the diet for four to six weeks. The copper content of the mitochondria in the control group of animals is 0.55 X 10(-9)M/mg protein. 0.20 X 10(-9) M/mg protein in the copper-deficient rats and 1.8 X 10(-9) M in the copper-loaded rats. Digitonin resistance is measured by the degree of increase in the activity of a matrix enzyme, malatedehydrogenase, upon destruction of the various mitochondrial membranes and to a different degree by ascending digitonin concentrations. The digitonin effect on the membranes is maximal for concentrations of 0.8 to 1.0 mg digitonin/mg protein. The digitonin resistance of the inner membranes increases in the case of copper deficiency, while coppor loading has the opposite effect on the resistance of the outer membranes. Moreover, coppor loading results in an increase in the general activity of the mitochondrial malatedehydrogenase as compared with the control mitochondria.

Animals↗

Inherited, chronic, progressive hepatic degeneration in Bedlington terriers with increased liver copper concentrations: clinical and pathologic observations and comparison with other copper-associated liver diseases.

One hundred nineteen hepatic tissue samples from 117 Bedlington Terriers were divided into 6 groups depending on the severity of histopathologic hepatic changes. Group 0 comprised dogs with microscopically normal livers. Group I dogs had copper-positive, lipofuscin-containing lysosomes present in centrilobular hepatocytes. Microfoci of hepatic necrosis, in addition to the increased numbers of the copper-positive, lipofuscin-containing lysosomes in centrilobular and periportal hepatocytes, were present in group II dogs. Group III dogs had more copper-positive, lipofuscin-containing lysosomes present translobularly and morphologic changes consistent with chronic active hepatitis. Mixed micro- or macronodular cirrhosis and translobular presence of copper-positive, lipofuscin-containing lysosomes characterized group IV dogs. Dogs in group V had massive hepatic necrosis and morphologic changes that were consistent with the changes in group III and IV dogs. Histochemical staining for copper was useful in making the microscopic diagnosis of this disease and was shown to be necessary in early diagnosis (group I) when other clinical and pathologic values associated with this syndrome were not consistently abnormal. Copper histochemical stains varied in sensitivity. Timm's silver sulfide was more sensitive for copper than was rubeanic acid, which was more sensitive than rhodanine staining. The brown pigment associated with the copper in the lysosomes was shown to be lipofuscin pigment with the aid of histochemical staining with orcein, Prussian blue, periodic acid-Schiff, and acid-fast stains together with fluorescent microscopy (excitation maxima: 365 nm; emissions: 420 + nm). Since these were positive only in later stages of the hepatic disease, they were not especially useful in its early diagnosis. The severity of the histopathologic hepatic changes was shown to increase with age and was associated with increasing hepatic copper concentration. These observations illustrate that this inherited, chronic hepatic degeneration in the Bedlington Terrier is progressive. Clinical chemical tests were diagnostically useful only in later stages of the disease. Alanine transaminase activity was of most value, but was not always abnormal, even when severe hepatic damage was present. Clinical signs of hepatic disease were seen in dogs in groups III, IV, and V. Death due to hepatic failure occurred only in dogs in groups III, IV, and V. Hemosiderin was present in increased amounts in the liver, bone marrow, spleen, and lymph nodes of affected Bedlington Terriers, indicating that a possible defect in iron metabolism and/or an increase in RBC turnover existed.(ABSTRACT TRUNCATED AT 400 WORDS)

Alanine Transaminase↗

[Comparative studies on the effect of injections of copper in cattle showing low blood copper concentrations (author's transl)].

On a number of farms on which the young stock showed symptoms of copper deficiency, copper was injected in the form of the following compounds: Biodalbene, Robasfer and Coprin. The effects of the agents administered on the copper status of the animals were compared. This showed that there only is an effect when the concentration of copper in the blood is low (less than or equal to 50 mg/l. of blood serum). The most satisfactory results were obtained by administration of Coprin (100 mg as copper-calcium edetate) followed by Robasfer (40 mg. of copper at the recommended dosage of 25 ml), administration of Biodalbene failing to produce any improvement in copper status, which hardly could be expected by such low copper content (0.135 mg/ml). When there are practical objections to administering copper in the form of concentrates or top dressing to young stock, it is entirely practicable to use the compounds Coprin and Robasfer for this purpose.

Animals↗

Copper deficiency prophylaxis in grazing sheep by copper oxide injection.

21 ewes weighing about 46 kg were transfered to grass on a copper deficient Rye Grass pasture. 11 ewes were injected intramuscularly with 60 mg of copper as copper oxide (CuO) suspended in 5 ml of purified olive oil. The concentration of copper in the plasma of control ewes declined during the 67 days of experiment and three became copper deficient. The injected ewes were protected against deficiency and had higher concentration of copper in plasma than the controls throughout the experiment. At slaughter the amount of copper in the liver of the treated animals was significantly higher than in the untreated controls. The copper dose used (60) mg) is probably a maximum for adult sheep since one of the injected ewes at slaughter had a liver copper content of 1060 micrograms/g D.M. which approaches the toxic limit.

Animals↗

Copper oxide powder as a copper supplement for sheep.

The ability of oral doses of copper oxide powder to raise liver and blood copper concentration was examined in penned sheep given a pelleted diet containing 4 mg of copper per kg dry matter. Merino sheep of similar live weight and liver copper concentration were allocated at random to one of six treatment groups of four sheep each. Treatment groups received nil, 2.5 g, 5 g, 10 g, 20 g and 40 g of cupric oxide powder. The cupric oxide powder of sieve size 250-350 microns was effective in raising the liver copper concentration for at least 12 weeks. The large particles of oxide powder were retained in the gut for at least 13 days after dosing. Sheep given 10-40 g doses of cupric oxide powder were at risk of copper toxicity, as indicated by elevated plasma enzyme activities, liver copper concentrations and reduced liveweight gains. It was concluded that a 2.5 g dose of cupric oxide powder could be used to prevent short periods of copper deficiency in sheep at pasture without risk of copper toxicity.

Administration, Oral↗

A NMR study of the interaction of a three-domain construct of ATP7A with copper(I) and copper(I)-HAH1: the interplay of domains.

ATP7A is a P-type ATPase involved in copper(I) homeostasis in humans. It possesses a long N-terminal tail protruding into the cytosol and containing six copper(I)-binding domains, which are individually folded and capable of binding one copper(I) ion. ATP7A receives copper from a soluble protein, the metallochaperone HAH1. The exact role and interplay of the six soluble domains is still quite unclear, as it has been extensively demonstrated that they are strongly redundant with respect to copper(I) transport in vivo. In the present work, a three-domain (fourth to sixth, MNK456) construct has been investigated in solution by NMR, in the absence and presence of copper(I). In addition, the interaction of MNK456 with copper(I)-HAH1 has been studied. It is proposed that the fourth domain is the preferential site for the initial interaction with the partner. A significant dependence of the overall domain dynamics on the metallation state and on the presence of HAH1 is observed. This dependence could constitute the molecular mechanism to trigger copper(I) translocation and/or ATP7A relocalization from the trans-Golgi network to the plasmatic membrane.

Adenosine Triphosphatases↗

Biliary excretion of copper in Fischer rats treated with copper salt and in Long-Evans cinnamon (LEC) rats with an inherently abnormal copper metabolism.

Increased biliary Cu excretion was found in Fischer rats injected with Cu. The biliary Cu was located at the void (large-molecule region) and total (small-molecule region) volume of a Sephadex G-75 column. The most Cu was found in the total volume. The two Cu peaks comigrated with absorbance at 280 nm. Although the bile from Cu-untreated Fischer rats did not show Cu absorbance in the total volume, absorbance at 280 nm was also found in this region. Even though Long-Evans Cinnamon (LEC) rats deposited a gross amount of Cu (194.0 +/- 27.8 micrograms/g liver) in the liver, they conversely showed reduced Cu excretion into the bile. LEC bile did not show Cu absorbance but rather absorbance at 280 nm in the total volume. Therefore, it seems unlikely that the small molecules found in the Sephadex G-75 regulate biliary Cu excretion in Cu-loaded rats, although the molecules bind to Cu. When the bile from Cu-untreated Fischer and LEC rats was incubated with CuCl2 solution, the most Cu was recovered in the total volume of this column. Our results suggest that reduced biliary Cu excretion in LEC rats is not related to the small molecules, and that Cu cannot be excreted in the form of macromolecules in rats to decrease Cu from the Cu-loaded liver.

Animals↗

Competition between copper and silver in Fischer rats with a normal copper metabolism and in Long-Evans Cinnamon rats with an abnormal copper metabolism.

Long-Evans Cinnamon (LEC) rats inherently lacking in serum ceruloplasmin (CP) activity and biliary Cu excretion were established from a closed colony of Long-Evans rats. These deficiencies, linked to a dysfunction of P-type ATPase, stimulate deposition of Cu and then of Cu metallothionein (MT) in the liver. Male LEC and Fischer rats were injected subcutaneously with Ag (AgNO3), which is an antagonist to Cu. They were operated on 24 h after the injection while under anesthesia. Total uptake of Ag into the liver was not stimulated, but its uptake into the MT fraction increased significantly in the LEC rats. Ag injection notably decreased the activity of serum CP in the Fischer rats, but not in the LEC rats. The decrease was accompanied by a reduction of serum Cu. In Fischer rat serum treated with Ag, Ag was detected mainly in the albumin region and partly in the CP fraction. In LEC rat serum, however, the Ag concentration was about 1/20 of that in the Fischer rats, and Ag was not detected in the CP fraction. Ag injection decreased the biliary excretion of Cu in the Fischer rats (0.183-0.052 microg Cu/20 min sampling), but not in the LEC rats (0.014-0.014 microg Cu/20 min sampling). On the other hand, biliary excretion of Ag was much greater in the Fischer rats (1.25 microg Ag/20 min) than in the LEC rats (0.04 microg Ag/20 min). Our results suggest that uptake of Ag into the liver is not dependent on the hepatic Cu content and status, but that biliary excretion of Ag from the liver is affected by these. Hepatic MT is not a transporter of hepatobiliary excretion of Cu and Ag. It seems likely that, unlike Cu excretion, Ag is excreted by not only the CP route but also by another route into the serum. Ag may compete with Cu in the uptake into CP (conversion of apo-CP to holo-CP).

Animals↗

A copper deficient diet prevents hepatic copper accumulation and dysfunction in Long-Evans Cinnamon (LEC) rats with an abnormal copper metabolism and hereditary hepatitis.

Long-Evans Cinnamon (LEC) rats that develop spontaneous hepatitis due to an inherently abnormal Cu metabolism have recently been established. This investigation concerns the effects of a Cu-deficient diet on the Cu metabolism linked to hepatic injury in LEC rats. The hepatic Cu concentration at 30 days after birth was 94 +/- 4 Cu micrograms/g liver in LEC rats, whereas that of Fischer rats at the same age was 7 +/- 1 Cu micrograms/g. From 30 days after birth, all rats were fed a semisynthetic diet with two different levels of Cu, 0.5 or 30 micrograms/g food, for 35 days. In LEC rats fed a Cu-deficient diet (0.5 microgram/g), the hepatic Cu concentration was 39 +/- 7 micrograms/g. The Cu-normal diet (30 micrograms/g) LEC group had a concentration of 357 +/- 15 micrograms/g in the hepatic Cu. The group had significantly higher aspartate aminotransferase (ASAT), alanine aminotransferase (ALAT) and gamma-glutamyl transferase (GGT) levels than did the LEC rats given the Cu-deficient diet. These results suggest that the occurrence of acute hepatitis in LEC rats can be prevented by feeding the animals a Cu-deficient diet.

Animals↗

A randomised comparative evaluation of the copper 7, multiload copper 250 and T copper-22OC IUDs.

Two new Cu-IUDs, the TCu-22OC and Multiload Cu250, were evaluated against the Cu7 in 1,199 subjects in a randomised, multicentric trial using a common study protocol. During the 2 years following insertion, cumulative first-segment rates for total use-related terminations showed no significant differences between the 3 devices; however, the Cu7 had a significantly higher termination rate for accidental pregnancy compared to the TCu-22OC and its expulsion rate was significantly higher than the ML Cu250. The rate of accidental pregnancy was higher and the expulsion rate lower with the ML Cu250 compared to the TCu-22OC but these differences were not significant. The results are discussed in relation to IUD design and their application in family planning.

Adult↗