Micro-determination of copper in biological material

Micronutrients in Human Milk: Analytical Methods

Exclusive breastfeeding is recommended by the WHO for the first 6 mo of life because human milk protects against gastrointestinal infections and supplies balanced and adequate nutrient contents to the infant. However, reliable data on micronutrient concentrations in human milk are sparse, especially because some micronutrients are affected by maternal diet. Microbiological and competitive protein-binding assays, nuclear magnetic resonance or inductively coupled plasma spectroscopy, and chromatographic analyses are among the methods that have been applied to human-milk micronutrient analysis. However, the validation or evaluation of analytical methods in terms of their suitability for the complex human-milk matrix has been commonly ignored in reports, even though the human-milk matrix differs vastly from blood, plasma, or urine matrixes. Thus, information on the validity, accuracy, and sensitivity of the methods is essential for the estimation of infant and maternal intake requirements to support and maintain adequate milk micronutrient concentrations for healthy infant growth and development. In this review, we summarize current knowledge on methods used for analyzing water- and fat-soluble vitamins as well as iron, copper, zinc, iodine, and selenium in human milk and their different forms in milk; the tools available for quality control and assurance; and guidance for preanalytical considerations. Finally, we recommend preferred methodologic approaches for analysis of specific milk micronutrients.

Experimental Poisoning by Senecio jacobaea in Pigs

Seven pigs were poisoned by feeding from 1 to 3 months with Senecio jacobaea (“ragwort”). Clinically, the disease induced was characterised by dyspnœa and fluctuating pyrexia, anatomically by firm, heavy, discoloured, oedematous lungs and histologically by pulmonary oedema, congestion, haemorrhage and alveolar epithelialisation, and by hepatic and renal karyomegaly.

Ragwort poisoning in pigs was compared with groundnut poisoning and it was concluded that the two are unlikely to be confused.

Urinary copper excretion before and after oral intake of d-penicillamine in parents of patients with Wilson's disease

BACKGROUND

Urinary copper excretion higher than 100 μg/24 h is useful for diagnosing Wilson's disease. d-Penicillamine challenge test may produce higher levels than 1400 μg/24 h, allowing for better diagnostic accuracy. This study investigated whether heterozygotes reach this value and compared copper serum levels, ceruloplasmin, and urinary copper excretion before and after administering d-penicillamine to the parents of Wilson's disease patients.

METHODS

Fifty parents of adult patients were enrolled to obtain copper serum levels and ceruloplasmin along with 24-h urinary copper excretion before and after administering 1g d-penicillamine.

RESULTS

Serum ceruloplasmin and copper levels were significantly lower in fathers than in mothers (mean 21.8×27.8 mg%; 71.4×88.0 μg%; p ≤ 0.001). The mean of basal 24-h urinary copper excretion was higher in fathers (26.2×18.7 μg/24 h, p=0.01), but did not differ between the genders after d-penicillamine (521.7×525.3, range 31.6-1085.1 μg/24h, p=0.8).

CONCLUSIONS

The mean values of serum copper, ceruloplasmin, and basal urinary copper excretion were different between males and females. The current diagnostic threshold of 24-h urinary copper excretion after d-penicillamine was not reached by heterozygotes. The increased urinary copper excretion after d-penicillamine challenge was much higher than fivefold the upper limit of normal urinary copper excretion in the majority of heterozygotes and should not be taken into account when diagnosing Wilson's disease.

THE DEPOSITION OF EXOGENOUS COPPER UNDER EXPERIMENTAL CONDITIONS WITH OBSERVATIONS ON ITS NEUROTOXIC AND NEPHROTOXIC PROPERTIES IN RELATION TO WILSON'S DISEASE

Goldfish kept in water containing ionized copper and a detergent added with the aim of decreasing coagulation of the mucus on the gills, took in and retained this metal in their brains, livers, and kidneys, in concentrations comparable to those that occur naturally in Wilson's disease, as chemical assays disclosed. Histochemical studies made it clear that much copper had accumulated within the large neurons, principally in those of the telencephalon and anterior horn region of the spinal cord and in the tubular epithelial cells of the kidneys, the nuclei of the parenchymal cells of the liver, the sarcoplasm of the skeletal muscle, and in the epithelial covering of the gills. The intraneuronal deposition of copper was regularly associated after a time with conspicuous cytologic changes, notably contraction and hyperchromaticity of the nerve cells with tortuosity and fragmentation of the axis cylinders and lysis and loss of neurons. The accumulation of metal in the renal epithelium was frequently accompanied by necrosis and was regularly associated with hyperplasia and calcification of the epithelial cells of the larger renal tubules in all goldfish kept for prolonged periods in copper-rich water. The deposition of copper in the liver was not accompanied by consistent cytologic changes. The similarity of the cytologic alterations induced in the central nervous systems by copper and those that occur naturally in hepatolenticular degeneration in human beings provides evidence that copper itself plays an important role in the pathologic alterations of the brain in Wilson's disease.

Tallowy discoloration and trace metals in cheddar cheese

The characteristics are given of a Chaddar cheese defect known as ‘tallowy discoloration’ or ‘white streak’. In the tallowy portions of the cheese the copper content is lower and the iron content higher than in the adjacent normal cheese. The copper probably migrates in cheese following oxidation of the sulphydryl compounds in the tallowy area while the unexpected distribution of iron may be explained by changes that occur during salting of the curd. The proportion of ferrous to ferric iron tends to increase as the cheese matures and tallowy portions of cheese do not contain less ferrous iron than adjacent portions.

The addition of iron salts to cheese milk did not increase the incidence of tallowy discoloration, but the addition of sufficient copper salts reduced it. Although the sulphydryl content of cheese appeared to be related to tallowy discoloration, little evidence of the part it plays was obtained. The oxidation of sulphydryl groups and the formation of peroxides occurred more readily at lower temperatures.

The significance is discussed of ferrous iron in a fat-oxidizing system where copper does not increase oxidation.

351. The estimation of copper and iron in cream, butter and dry butterfat

1. A method is described based on wet-ashing in micro-Kjeldahl flasks for the accurate estimation of iron and copper in 10g. samples of butter or dry butterfat or in 5g. samples of cream.

2. An acid extraction method for the routine estimation of copper and iron in dry butterfat is described. This method is shown to give a reliable estimate of the quantities of the metals present.

3. A simplified method for the estimation of iron in cream and butter is described in which the iron is first freed from its protein complex by the addition of thioglycollic acid. Copper is estimated by a similar method, but without the addition of a reducing agent. Both methods give results agreeing reasonably well with the wet-ashing method and are suitable for the routine estimation of these metals in cream and butter.

437. Copper and iron in dairy produce. improved methods of analysis

1. Improvements are described in the methods for the extraction and colorimetric estimation of metals in dairy produce, using the carbamate reagent for copper and thiocyanate for iron.

2. A combined filtration procedure has been developed to enable both metals to be determined on the same sample, and with slight modifications this procedure has been applied to the analysis of samples of butter, cream, buttermilk and whey.

3. The wet-ashing technique has also been improved to enable it to be used for the estimation of both metals on the same digest.

4. Comparisons show that the combined filtration method is capable of giving results which agree very well with those yielded by wet-ashing.

5. The results of many analyses show that the majority of creamery butter samples have a satisfactorily low content of both copper and iron.

6. Many whey butter samples have a rather high metallic content.

7. Notes are given on the results obtained when the methods described are applied to other dairy produce.

Studies on the nature and properties of the perienteric fluid ofAscaris lumbricoides

1. The composition of the perienteric fluid ofAscaris lumbricoidesof the pig, immediately after removal from the host and after varying periods ofin vitrostarvation, is recorded.

2. Apart from the more frequently observed constituents of invertebrate tissue fluids, the body fluid ofAscariswas found to contain ascorbic acid, amino sugar and small amounts of uronic acid.

3. Large amounts of anion other than chloride, probably fatty acid, must have been present in the body fluid, though chloride was probably the predominant anion in fluids of parasites which had passed several days ofin vitrolife.

4. The chief factors (starvation, osmotic pressure and the nature of the medium, etc.) affecting the composition of the body fluid are briefly discussed.

Leukoencephalomyelopathy in specific pathogen-free cats

Investigations were carried out on 8 specific pathogen-free cats (5 male and 3 female) from a colony experiencing "outbreaks" of progressive hind limb ataxia in 190 of 540 at-risk animals ranging from 3 months to 3 years old. These studies identified moderate to severe bilateral axonal degeneration within white matter regions of the cervical, thoracic, and lumbar spinal cord and in the white matter of the cerebral internal capsule and peduncle, in the roof of the fourth ventricle and inferior cerebellar peduncle, and in the external arcuate and pyramidal fibres of the medulla. There were varying degrees of accompanying microgliosis, astrocytosis, and capillary hyperplasia. Such a clinicopathologic syndrome, termed feline leukoencephalomyelopathy, has previously been described in cat colonies in Britain and New Zealand, although its etiology has not been determined. The degenerative nature of the lesions and their bilateral distribution suggest possible nutritional, metabolic, or toxic causes. Although these findings provide circumstantial evidence that the exclusive feeding of a gamma-irradiated diet of reduced vitamin A content is associated with the development of the neuronal lesions, further tissue micronutrient and antioxidant analysis will be required to support this hypothesis.

Morphologic alterations produced by copper in neural tissues with consideration of the role of the metal in the pathogenesis of Wilson's disease

The injection into the cerebrospinal fluid of cats of 52 to 208 gamma of copper in the form of an albumin complex or as cupric sulfate, was followed by small elevations in the content of metal in the neural tissues, but regularly and promptly produced persistent quadriplegia and conspicuous histologic changes. Smaller amounts of copper caused less, or no, neurologic manifestations or histologic alterations. The earliest lesions were essentially unaccompanied by inflammation and were initially characterized by hydropic swelling of the myelin sheaths. They progressed rapidly to focal necrosis of all parenchymal components with marked degeneration of myelin and axis cylinders in the peripheral margins of the spinal cord, brain stem, mid-brain, and cerebrum. These histologic changes did not occur in neural tissues incubated in vitro in solutions of the copper-albumin complex. They did not appear in animals injected intraventricularly with ferric sulfate or saccharated iron. Considered together, the findings make it clear that copper in concentrations comparable to those present in the neural tissues of patients with Wilson's disease has the property of profoundly altering neural function and causing conspicuous morphologic alterations.

Failure of simple biochemical indexes to reliably differentiate fulminant Wilson's disease from other causes of fulminant liver failure

Serum, urine and tissue biochemical findings were studied in 21 cases of fulminant Wilson's disease with respect to the value of a recently described biochemical index based on serum alkaline phosphatase and total serum bilirubin levels, and these cases were compared with 193 other cases of fulminant liver failure. Serum bilirubin, alkaline phosphatase and AST levels found in fulminant Wilson's disease were significantly different from those found in other cases of fulminant liver failure, but differentiation from other causes of fulminant liver failure on the basis of these biochemical parameters was not possible. The alkaline phosphatase/bilirubin and aspartate AST/bilirubin ratios derived from the above parameters were also significantly lower in fulminant Wilson's disease than in other categories of fulminant liver failure, but distinction between diagnostic categories on this basis was not possible. When ratios that correctly identified all cases of fulminant Wilson's disease were selected, 59/190 (31%) and 84/190 (44%) cases of non-Wilsonian fulminant liver failure would erroneously be assigned a diagnosis of fulminant Wilson's disease, by alkaline phosphatase/bilirubin and AST/bilirubin ratios, respectively. A low alkaline phosphatase-to-bilirubin ratio (< 0.57) in any category of fulminant liver failure suggested a significantly worse prognosis than in cases with higher ratios (chi 2, Yates' corrected = 5.37, p = 0.02). In the Wilson's disease group, serum and hepatic copper and ceruloplasmin concentrations were normal in 4/21, 2/15 and 2/19, respectively, whereas urinary copper level was elevated in 18/18 and was the most valuable test in diagnosis.(ABSTRACT TRUNCATED AT 250 WORDS)

Value of urinary copper excretion after penicillamine challenge in the diagnosis of Wilson's disease

To investigate the diagnostic value of 24-hr urinary copper excretion testing after penicillamine challenge in the diagnosis of Wilson's disease, 75 consecutive children referred for a variety of liver problems and in whom parameters of copper metabolism had been investigated were analyzed retrospectively. Seventeen had Wilson's disease, 22 had autoimmune chronic active hepatitis, 6 had primary sclerosing cholangitis, 12 had chronic liver disease of various etiologies, 4 had cryptogenic acute liver failure, 6 had acute hepatitic illnesses and 8 had a variety of disorders featuring normal liver histological appearance. Serum ceruloplasmin and total copper levels were significantly lower in Wilson's disease patients compared with all other groups, but three children with Wilson's disease had normal ceruloplasmin levels and seven had normal total copper levels. No significant difference was found for free serum copper levels and liver copper content between Wilson's disease patients and the other groups. Baseline 24-hr urinary copper excretion was significantly higher in Wilson's disease patients compared with that of the other patients, but six children with Wilson's disease had levels just above the upper limit of normal, overlapping with values obtained in three children with liver failure, two with acute hepatitis, two with autoimmune chronic active hepatitis and three with primary sclerosing cholangitis. The 24-hr urinary copper excretion after penicillamine challenge proved the most accurate single diagnostic test; levels more than 25 mumol/24 hr were present in 15 of 17 patients with Wilson's disease, but in only 1 child with liver failure of the 58 with other disorders.(ABSTRACT TRUNCATED AT 250 WORDS)

An unusual neurological disorder with abnormal copper metabolism

Twin males aged 24 years showed dementia, dysarthria, gait disturbances and involuntary movements, with slightly low levels of serum copper and ceruloplasmin, and markedly low excretion of urinary copper. We propose that the unique combination of dementia, dysarthria, gait disturbances, involuntary movements and abnormalities of copper metabolism does not fit any known nosological entity and constitutes a "new" syndrome different from Wilson's and Menkes' diseases.

Biodistribution of 64Cu in inflamed rats following administration of two anti-inflammatory copper complexes

64Cu was administered in two anti-inflammatory formulations to normal rats and to rats with 2 forms of local inflammation, namely (a) an acute paw oedema (elicited with carrageenan) or (b) a chronic granulomatous response to an implanted irritant (Mycobacterium tuberculosis in a polyurethane sponge). The copper formulations used were (i) a slow release one consisting of Cu(II) salicylate applied dermally with ethanol/DMSO and (ii) short acting hydrophilic complex (Cu(I)Cu(II)-penicillamine)5- given subcutaneously. Three types of changes in copper biodistribution with these forms of inflammation were discerned based on determination of 64Cu and copper content in the following organs: inflammatory locus (foot or sponge implant), kidney, liver, spleen, adrenals, brain, blood, thymus, heart, and skin (site of application). The most evident changes were in the kidneys, liver, spleen, adrenals, thymus and serum from animals with chronic granulomatous inflammation. In contrast, a short term acute inflammatory stress (carrageenan paw oedema) had little effect. While copper D-penicillamine (applied subcutaneously) appeared to move as a bolus through the animals, the results with the percutaneous copper salicylate formulation are consistent with it providing a slow release source of copper(II). Exogenous 64Cu from both formulations was sequestered at inflammatory sites (relative to serum). This may partly explain how applied copper complexes can be anti-inflammatory.

Plasma alkaline phosphatase as a screening test for low zinc status in broiler hybrid chickens affected with 'clubbed down'

Broiler chickens affected by 'clubbed down' on a number of Victorian farms had low liver zinc concentrations and low plasma alkaline phosphatase activities. The results indicated that the zinc status of affected flocks should be considered in future studies and that measurement of plasma alkaline phosphatase activity may be a useful means of screening large numbers of samples. Nutritional and genetic factors may be involved in the aetiology of 'clubbed down'.

Blood selenium in chronic spinal muscular atrophy

The spinal muscular atrophies (SMA) of childhood comprise the second most common fatal recessive disease after cystic fibrosis, yet the nature of the biochemical defect causing the anterior horn cell degeneration is totally unknown. Recent reports of a cluster of adult motor neurone disease cases from a high seleniferous area in South Dakota have prompted the study of blood selenium in children with SMA in Australia. Eight children with chronic SMA were tested, in addition to 9 obligate heterozygote carriers of the gene. Blood selenium levels of patients and carriers did not differ significantly from that observed in controls. The mammalian effects of selenium toxicity are discussed.

An unusual neurological disorder of copper metabolism clinically resembling Wilson's disease but biochemically a distinct entity

A patient with progressive neurological disease resembling Wilson's disease but in whom Kayser-Fleischer rings were absent, was given 67Cu and 64Cu, orally and intravenously, to measure the rate of absorption of copper using a convolution integral. The data show an abnormal distribution of body copper resulting in low copper concentrations in plasma, urine and liver but with an accumulation in the lower bowel probably due to a defect in mucosal transport. The importance of differentiating this condition from Wilson's disease is stressed.

Purification and properties of the methane mono-oxygenase enzyme system from Methylosinus trichosporium OB3b

1. A three-component enzyme system that catalyses the oxidation of methane to methanol has been highly purified from Methylosinus trichosporium. 2. The components are (i) a soluble CO-binding cytochrome c, (ii) a copper-containing protein and (iii) a small protein; the mol. wts. are 13 000, 47 000 and 9400 respectively. The cytochrome component cannot be replaced by similar cytochrome purified from Pseudomonas extorquens or by horse heart cytochrome c. 3. The stoicheiometry suggests a mono-oxygenase mechanism and the specific activity with methane as substrate is 6 micronmol/min per mg of protein. 4. Other substrates rapidly oxidized are ethane, n-propane, n-butane and CO. Dimethyl ether is not a substrate. 5. The purified enzyme system utilizes ascorbate or, in the presence of partially purified M. trichosporium methanol dehydrogenase, methanol as electron donor but not NADH or NADPH. 6. Activity is highly sensitive to low concentrations of a variety of chelating agents, cyanide, 2-mercaptoethanol and dithiothreitol. 7. Activity is highly pH-dependent (optimum 6.9-7.0) and no component of the enzyme is stable to freezing. 8. The soluble CO-binding cytochrome c shows oxidase acitivity and the relationship between this and the oxygenase activity is discussed.

Copper metabolism in retinitis pigmentosa

Clinically and electrophysiologically confirmed cases of primary retinitis pigmentosa have been investigated regarding their copper metabolic state. It is observed that these patients show a normal or near normal serum copper concentration, very low plasma caeruloplasmin concentration, and a very high copper urinary excretion. A similarity between this condition and hepatolenticular degeneration is drawn and it is suggested that retinitis pigmentosa may also be a condition caused by an inborn error of copper metabolism.