Effect of sulfite exposure on zinc, iron, and copper levels in rat liver and kidney tissues

Sulfite is a potentially toxic molecule that might enter the body via ingestion, inhalation, or injection. For cellular detoxification, mammalians rely on sulfite oxidase to convert sulfite to sulfate. The purpose of this research was to determine the effect of sulfite on zinc, iron, and copper levels in rat liver and kidney tissues. Forty normal and sulfite oxidase-deficient male albino rats were divided into four groups that included untreated controls (group C), a sulfite-supplemented group that received 70 mg sodium metabisulfite per kilogram per day (group S), a sulfite oxidase-deficient group (group D), and a sulfite oxidase-deficient group that was also given 70 mg sodium metabisulfite per kilogram per day (group DS). The iron and zinc levels in the liver and kidney in groups S and DS were not affected by sulfite treatment compared to their respective controls (groups C and D). Sulfite exposure led to an increase of kidney copper content in the S group when compared to untreated controls. The kidney copper levels were significantly increased in the unexposed deficient rats, but it was not different than that of the deficient rats that were given oral sulfite treatment. These results suggest that kidney copper levels might be affected by exogenous or endogenous sulfite. An erratum to this article is available at .     

Concentrations of cadmium,zinc, copper,iron, and metallothionein in liver and kidney of nonhuman primates

To evaluate the species specificity of Cd accumulation and the relationship of Cd with other essential metals and metallothionein (MT), the concentrations of Cd, Zn, Cu, and Fe in the liver and kidney and the MT concentrations in the soluble fractions of the liver and kidney were determined in Cd-uncontaminated nonhuman primates (11 species, 26 individuals) kept in a zoo and two wild-caught Japanese macaques. The compositions of metal-binding proteins in the soluble fractions were also investigated by high-performance liquid chromatography (HPLC). The hepatic Cd concentration was 0.03–14.0 μg/g and the renal Cd concentration was 0.35–99.0 μg/g, both varying greatly and being higher in nonhuman primates, which were more closely related to man. The hepatic Zn concentration was 24.0–176 μg/g and the renal Zn concentration was 13.5–138 μg/g, showing 7- to 10-fold differences, and a correlation (r=0.558, p<0.01) was found between renal Zn and renal Cd concentrations. It was proved that in the liver, MT is more closely correlated with Zn (r=0.795, p<0.001) than with Cd (r=0.492, p<0.01) and that in the kidney MT is correlated with both Cd (r=0.784, p<0.001) and Zn (r=0.742, p<0.001). HPLC analysis of metals bound to MT-like protein in chimpanzees, de Brazza’s monkeys, and Bolivian squirrel monkeys showed that more than 90% of Cd in both the liver and kidney, approx 40% of Zn in liver and 28–69% of Zn in kidney were bound to MT-like protein. The higher percentage Zn was bound to high-molecular protein.     

Effect of long-term swimming exercise on zinc,magnesium, and copper distribution in aged rats

Trace element content of different tissues might be altered by both age and exercise training. We aimed to determine the effects of a 1-yr swimming protocol (60 min/d, 5 day/wk) on tissue levels and the distribution of zinc (Zn), magnesium (Mg), and copper (Cu) in aging rats. Three groups were formed: sedentary and trained old groups and a young control group. Tissue Zn, Mg, and Cu concentrations were measured in the kidney, heart, liver, lungs, and gastrocnemius and soleus muscles. Kidney zinc concentration significantly decreased in the sedentary old group compared to the young control group (p<0.01) and was significantly higher in the trained old group compared to the sedentary old group (p<0.01), whereas Zn levels in the soleus muscle significantly increased in the sedentary old group in comparison to young controls (p<0.05). Tissue Mg concentrations remained unchanged. The sedentary old group exhibited a significant decrease in kidney Cu concentration compared to the young control group (p<0.01). Although kidney Cu levels also decreased in trained old rats in comparison to young controls (p<0.05), they were significantly higher than in sedentary old rats (p<0.01). The decrease in kidney Zn and Cu content as a result of aging was partly prevented by long-term swimming exercise.     

Dietary zinc intake,supplemental zinc intake and serum zinc levels and the prevalence of kidney stones in adults

ObjectiveThe association between zinc intake and the risk of kidney stones remains controversial. We examined the associations between dietary zinc intake, supplemental zinc intake and serum zinc levels and the prevalence of kidney stones in adults.MethodsAdult participants from the 2007–2016 NHANES were included. Restricted cubic splines were adopted to assess the dose-response relationships.ResultsDietary zinc intake was linearly associated with the prevalence of kidney stones (P_{for non-linearity} = 0.50), and the odds ratios (95% confidence intervals) of kidney stones were 0.75 (0.51–1.04) for 10 mg/day, 0.65 (0.39-0.97) for 20 mg/day, 0.53 (0.30-0.94) for 30 mg/day and 0.45 (0.22-0.95) for 40 mg/day. The linear relationship was also observed among women and overweight/obese individuals. No association was found between supplemental zinc intake and the prevalence of kidney stones. A non-linear relationship was found between serum zinc levels and the prevalence of kidney stones (P_{for non-linearity} = 0.02), and the odds ratios (95% confidence intervals) of kidney stones were 0.52 (0.33-0.82) for 70 ug/dL, 0.43 (0.24-0.77) for 90 ug/dL, 0.56 (0.32-0.98) for 110 ug/dL and 0.77 (0.37–1.62) for 130 ug/dL. The non-linear relationship was also observed among men and overweight/obese individuals.ConclusionsDietary zinc intake and serum zinc levels were inversely associated with the prevalence of kidney stones in adults, and there may be effect modification by participant sex and body mass index. The present analysis is limited in its ability to establish causality.     

Urinary excretion of mercury, copper and zinc in subjects exposed to mercury vapour

The excretion of mercury, copper and zinc in urine, and mercury in whole blood andplasma, was determined in 40 chloralkali workers exposed to mercury vapour and 40age-matched referents. The Hg concentrations in whole blood, plasma and urine werehigher in the exposed group (35 nmol l, 30 nmol l,and 11.5 nmol mmol creatinine, respectively) in comparison with thereference group (15 nmol l, 6.3 nmol l, and 1.8nmol mmol creatinine, respectively). The urinary copper excretionwas similar in the two groups, while U-Zn excretion was significantly higher (P = 0.04)in the exposed group, median 0.83 mmol mmol creatinine versus 0.76mnmol mmol creatinine in the reference group. In a subgroup of exposedworkers with current U-Hg above 11.5 nmol lmmolcreatinine (20 mg g creatinine) the medianU-Zn was 1.1 mmol mmol creatinine. In both groups smokers had highU-Zn levels than non smokers. When both U-Hg and smoking were taken into account in alinear regression model, there was a significant association between U-Hg and U-Zn inthe combined group of exposed and referents (P = 0.002). This study indicates thatmercury exposure in humans, as in animals, causes increased urinary excretion of zinc.The mechanisms may be induced synthesis of metallothionein in the kidneys, displacementof Zn from preexisting metallothionein by Hg, or a decreased reabsorption of zinc in thekidneys owing to a slight tubular dysfunction.     

Serum magnesium, copper, and zinc alterations following spinal fusion

Changes in serum magnesium, copper and zinc values were evaluated in spinal fusion patients at four monitorings. For magnesium and copper individually, a significant difference was found between the mean values at each monitoring (p<0.05), whereas the changes of zinc values between four monitorings were insignificant. There was no statistical difference between the changes of each trace element values and gender, age, operative time, intraoperative blood loss, blood replacement, number of the vertebral levels fused, and antibiotic type used. As a result, magnesium can be suggested to be more important than the other two elements in the postoperative period. Alterations of serum magnesium, copper, and zinc values do not have any correlation with the fusion of the spinal column, either with the width of the fused area or operative time and blood loss. This study cannot confirm the exact reason for this entity and the etiology remains speculative. There is no need for magnesium, copper, or zinc supplementation during the surgical period for the patients. It will be worthy to evaluate the patients who were sent to the intensive care unit after spinal surgery and compare their results with the other intensive care patients.     

Tissue and blood levels of zinc, copper, and magnesium in nitric oxide synthase blockade-induced hypertension

The aim of this study was to determine the levels of tissue and blood zinc (Zn), copper (Cu), magnesium (Mg) in nitric oxide (NO) synthase blockade-induced hypertension. A group of albino rats received a NO synthase inhibitor, N ^G -nitro-l-arginine-methyl ester (l-NAME, 60 mg/kg/d) in their drinking water for 21 d. l-NAME intake caused a progressive rise in this group’s resting mean arterial blood pressure compared to a control group (p<0.01). There were no differences between the groups with regard to tissue and blood levels of Zn or Cu; however, Mg concentrations were significantly lower in the hypertensive rats’ erythrocytes (20.2% reduction from control levels), cerebral cortex (17.0%), heart (9.1%), renal cortex (12%), renal medulla (16.7%), and in the tissues of the caval vein (23.7%), mesenteric artery (29.8%), renal artery (18.4%), and renal vein (22.1%). There were no significant Mg concentration changes in the hypertensive group’s plasma, cerebellum, liver, duodenum, or aortal tissue. These findings suggest that Mg depletion may play a role in the blood pressure rise that occurs in the model of chronic NO synthase inhibition-induced hypertension.     

Changes in iron, calcium, magnesium, copper, and zinc levels in different tissues of riboflavin-deficient rats

To clarify the changes of mineral levels in different tissues of riboflavin-deficient rats, Wistar rats were separated into three groups. One group was fed a diet ad libitum that was deficient in riboflavin. The other two were fed either the complete diet that was weight-matched to the riboflavin-deficient group or fed a complete diet ad libitum. In riboflavin-deficient rats, the hemoglobin concentration and riboflavin contents of blood, liver, and kidney were significantly decreased, compared with weight-matched and ad libitum-fed controls. The mineral concentrations of tissues are summarized as follows: The iron (Fe) concentration in the heart, liver, and spleen was decreased in the riboflavin-deficient group compared with the other groups. Calcium (Ca) and magnesium (Mg) concentrations in tibia were decreased in the riboflavin-deficient group compared with the other two groups. Copper (Cu) concentration was increased in the heart and liver when the riboflavin-deficient group was compared with the other groups. Zinc (Zn) concentration was increased in tibia when the riboflavin-deficient group was compared with the other groups.     

Cardiac copper,magnesium, and zinc in recent and old myocardial infarction

X-ray fluorescence spectrometry and atomic absorption spectrometry were used in a quantitative study of zinc, copper, and magnesium in 71 postmortal human hearts. Samples were obtained from individuals who had demonstrated no previous clinical or subsequent pathological findings of myocardial infarction and from victims of a recent or an old infarction. A significant difference (p<0.001) in the elemental levels was observed between the noninfarct and the recent infarct groups. The noninfarct group had higher cardiac levels of all three elements. However, the difference in elemental concentrations between the noninfarct and the old-infarct groups was not significant. Cardiac levels of zinc (p<0.001) and copper (p<0.01) were significantly greater in the old-infarct group than in the recent-infarct group. Magnesium levels were higher in the recent-and-old-infarct group than in the recent infarct group (p<0.01). It is possible that the elements are redistributed during myocardial infarction, and that uptake of these elements (from the serum pool) by the heart may be important in maintaining myocardial integrity and function.     

Macromolecular interactions with cadmium and the effects of zinc,copper, lead,and mercury ions

Interactions of cadmium (Cd) ions with bovine serum albumin (BSA), bovine hepatic metallothionein (MT), calf thymus histone and deoxyribonucleic acid (DNA), and bovine hepatic chromatins were studied in the presence and absence of divalent zinc (Zn), copper (Cu), mercury (Hg), or lead (Pb) ions, using equilibrium dialysis at pH 7 and at 37°C. The BSA had 3.5 Cd-binding sites with an apparent affinity constant of 1×10⁵. The other metal ions inhibited the binding by reducing the affinity constant and the number of Cd-binding sites in BSA. There were 6 high affinity and 13 low affinity Cd-binding sites in the MT. Zinc ions had poor efficacy in reducing the binding of Cd to the MT. However, the Cu²⁺ and Hg²⁺ ions inhibited the Cd binding to a considerable extent, the former ions being more potent in this respect. Histone did not bind Cd. There were two kinds of Cd-binding sites in DNA: One mole of Cd per four moles DNA-phosphorus at low affinity sites, and one mole of Cd per 6.7 moles DNA-phosphorus at high affinity sites. Their apparent association constants were 8.3×10⁵ and 4.4×10⁶ M, respectively. The other metal ions had inhibitory effects on the binding of Cd to DNA. Histone reduced the Cd-DNA interactions to only a minor extent. The other metal ions reduced the binding of Cd to DNA-histone complex to a small extent. Cadmium binds to the euchromatin (Euch), heterochromatin (Het), and Euch-Het mixture almost equally. The other metal ions reduced the binding maximally in Euch-Het followed next in order by Het and Euch. Cupric ions were the most potent inhibitors of the interactions of Cd with the nuclear materials.     

Effects of iron,copper, zinc,calcium, and magnesium on human lymphocytes in culture

The effects of simultaneous changes of calcium, magnesium, iron, copper, and zinc concentrations were evaluated in normal human T and B lymphocytes, cultured in cation-depleted media. Optimal concentrations for thymidine incorporation (TI) in both cell populations were Fe and Zn 15 μM and Cu 5 μM; for t cells Ca 2 mM and Mg 4 mM; for B cells Ca 4 mM and Mg 6 mM. TI decreased with increasing molarity of cations and the decrease was particularly apparent with Cu. Minimal amounts of Ca and Mg (0.5 mM) were necessary for growth, even in presence of optimal concentrations of Fe, Cu, and Zn. Fe and Cu showed synergistic stimulatory effects at low concentrations and synergistic inhibitory effects at high concentrations. Antagonism between Fe and Zn, Cu and Zn, and Ca and Zn was also demonstrated. CD4/CD8 increased with PHA stimulation in presence of Zn, and decreased with ConA stimulation in presence of Zn or Fe. The results demonstrate: (1) the relationship and interdependence of Fe, Cu, and Zn concentrations in modulating the growth of normal lymphocytes; (2) the stimulatory effects of Fe on B cells and Zn on CD8 positive cells; (3) the inhibitory effect of Cu at concentrations lower than those of Fe and Zn; (4) the requirement of Ca and Mg in certain concentration and ratio for the action of the other cations; and (5) the Ca and Mg requirement for the growth of B cells higher than T cells.     

Genetic differences in zinc and copper induction of liver metallothionein in inbred strains of the mouse

Differences in Zn-induced levels of hepatic metallothionein (MT) in inbred strains of the mouse are described. Three low-producing strains, C57BL/6, C57BL/10, and NIH, are identified, while C3H and CBA display the highest levels of hepatic MT following Zn treatment. These interstrain differences affect not only the level of MT protein, but also the amount of MT-bound Zn and the total hepatic Zn concentration. Both MT isoforms are equally affected. A similar interstrain difference following Cu treatment is present in C3H and C57BL/6. The origin of these interstrain differences is discussed.     

Relationship among levels of leptin and zinc,copper, and zinc/copper ratio in plasma of patients with essential hypertension and healthy normotensive subjects

Obesity is among the main contributing factors in the etiology of essential hypertension (EHT). Leptin, the product of the ob gene, is expressed mainly in adipose tissue. We examined the relationship between two trace elements, zinc (Zn) and copper (Cu), and leptin in patients with EHT (n=35) and normotensive (NT) controls (n=50) because leptin as well as Zn and Cu were reported to be associated with the pathophysiology of EHT. Plasma leptin levels were determined with a commercial enzyme-linked immunosorbent assay (ELISA) kit. Atomic absorption spectrophotometry was utilized to determine plasma Zn and Cu levels. There was a negative correlation between leptin and Zn, and the Zn/Cu ratio (r=−0.359, p<0.05; r=0.361, p<0.05, respectively) in pooled subjects. When subjects were divided based on the presence or absence of hypertension, there was a negative correlation between leptin and Zn (r=−0.375, p<0.05) as well as leptin and Zn/Cu ratio (r=−0.398, p<0.05) in NT subjects. Similar trends were observed when leptin/BMI (body mass index) levels were utilized. There was no significant correlations between levels of Cu and leptin or leptin/BMI. In conclusion, in addition to high leptin levels, Zn and the Zn/Cu ratio were lower in patients with EHT compared to NT controls.     

Effect of medium copper concentration on the growth,uptake and intracellular balance of copper and zinc in Menkes' and normal control cells

The precise nature of the variation in cellular copper load against medium copper concentration is defined using a comprehensive logarithmically incremented series of medium copper concentrations ranging from low levels (4.8 p.p.b.) through normal to toxic levels (40 p.p.m.) in which fibroblasts were grown followed by determination of intracellular content. Menkes' fibroblasts showed an unexpected plateau region of stable intracellular copper content against a change in medium concentration of over 100-fold, albeit only when sufficient copper was present in the medium (0.08–8.0 p.p.m.). Thus, Menkes' cells are clearly capable of balancing uptake/efflux providing copper availability allows. Simultaneous analysis of cellular copper and zinc load at various medium copper concentrations shows an indistinguishable intracellular copper:zinc ratio between the two cell lines. The nature of non-labeled copper uptake by fibroblasts over a 40 min and 7 day period is reported. During the 40 min period copper uptake (20 p.p.m.) was essentially the same in both cell lines. However, copper absorbed was superimposed upon large pre-existing copper pools in the case of Menkes' cells only. Advantages of techniques determining non-labeled copper in copper uptake/efflux experiments are discussed in the light of these results. Fibroblast growth studies showed that, compared with normal cells, Menkes' cells are significantly (P < 0.01) more growth sensitive to extended exposure to low copper concentrations. Thus, Menkes' disease appears to be not only a result of copper maldistribution but also a direct result of an inability of Menkes' cells to function normally in low copper environments.     

Chronological changes in tissue copper, zinc and iron in the toxic milk mouse and effects of copper loading

The toxic milk (tx) mouse is a rodent model for Wilson disease, an inherited disorder of copper overload. Here we assessed the effect of copper accumulation in the tx mouse on zinc and iron metabolism. Copper, zinc and iron concentrations were determined in the liver, kidney, spleen and brain of control and copper-loaded animals by atomic absorption spectroscopy. Copper concentration increased dramatically in the liver, and was also significantly higher in the spleen, kidney and brain of control tx mice in the first few months of life compared with normal DL mice. Hepatic zinc was increased with age in the tx mouse, but zinc concentrations in the other organs were normal. Liver and kidney iron concentrations were significantly lower at birth in tx mice, but increased quickly to be comparable with control mice by 2 months of age. Iron concentration in the spleen was significantly higher in tx mice, but was lower in 5 day old tx pups. Copper-loading studies showed that normal DL mice ingesting 300 mg/l copper in their diet for 3 months maintained normal liver, kidney and brain copper, zinc and iron levels. Copper-loading of tx mice did not increase the already high liver copper concentrations, but spleen and brain copper concentrations were increased. Despite a significant elevation of copper in the brain of the copper-loaded tx mice no behavioural changes were observed. The livers of copper-loaded tx mice had a lower zinc concentration than control tx mice, whilst the kidney had double the concentration of iron suggesting that there was increased erythrocyte hemolysis in the copper-loaded mutants.     

Comparison of angiotensin-converting enzyme, malonaldehyde, zinc, and copper levels in preeclampsia

Preeclampsia is a syndrome of unknown etiopathogenesis. Recent studies carried out on preeclampsia have focused on the increase in free radicals in the feto-placental unit with poor perfusion. It is believed that the renin-angiotensin system (RAS) has a role in the poor perfusion of the placenta. It is uncertain whether there is a pre-existing impairment in RAS in pre-eclamptic pregnant women or not. In the present study, we measured angiotensin-converting enzyme (ACE), malonaldehyde (MDA), zinc, and copper levels in the placental tissue of 16 pre-eclamptic pregnant women and compared them with those in 20 healthy pregnant women. Whereas ACE activity and MDA were found to be high in the placentas of pre-eclamptic patients, zinc and copper levels were low and there was a negative correlation between ACE activity and zinc concentration. These findings suggest that high ACE activity might play a role in the increase in tissue hypoxia and consequent lipid peroxidation through vasoconstriction; zinc deficiency in the placental tissue might cause insufficiency of superoxide dismutase, an antioxidant enzyme. Furthermore, deficiency in placental zinc also plays a role in the biosynthesis of connective tissue, maintaining its integrity, which might have an impact on the structure of the spiral arteries     

Maternal and neonatal scalp hair concentrations of zinc, copper, cadmium, and lead

Postpartum scalp hair samples from 82 term-pregnancy mother/neonate pairs were analyzed for their concentration of zinc (Zn), copper (Cu), cadmium (Cd), and lead (Pb), using inductively coupled plasma-mass spectrometry. Maternal and neonatal Zn concentrations had geometric means (and 99% confidence intervals) of 122.5 μg/g (117.9–131.5 μg/g) and 146.9 μg (141.5–156.7 μg/g) respectively. Corresponding Cu values were 18.4 μg/g (17.6–23.8 μg/g) and 6.7 μg/g (6.3–7.6 μg/g). Those of Cd were 0.49 μg/g (0.47–0.69 μg/g) in the mothers and 0.57 μg/g (0.55–0.86 μg/g) in the neonates. For Pb, they were 7.95 μg/g (7.60–9.32 μg/g) and 4.56 μg/g (4.39–5.56 μg/g). Cigaret smoking, despite its relatively low prevalence (19.5%), was associated with lower Zn and higher Cd and Pb concentrations and in lower Zn/Cd and Zn/Pb molar concentration ratios. Smoking also altered interelemental relationships, particularly those of Zn with Cd and Pb and those between Cd and Pb. Smoking frequency appeared to show negative dose-response effects on maternal and neonatal Zn concentrations, Zn/Pb molar concentration ratios, and birth weight. Mothers with a history of oral contraceptive (OC) usage had significantly higher Cu concentrations and lower Zn/Cu molar concentration ratios than nonusers, with the highest Cu concentrations and lowest Zn/Cu values being associated with third-generation OCs. No similar effects were elicited in the respective neonatal Cu concentrations. Neither alcohol consumption nor prenatal supplementation with iron and/or folic acid had discernible effects on the maternal or neonatal elemental concentrations. The data from this study suggest that in a given population of term-pregnancy mothers and neonates, significant interindividual variations in hair trace element concentrations can occur, irrespective of commonality of general environment, and that lifestyle factors, including cigaret smoking and OC usage history, can be significant contributory factors to such variations. The data are discussed in relation to the effects of smoking-associated exposure to Cd and Pb exposure on Zn availability for placental transfer, as well as on the quantitative maternal Zn supply levels to the fetus resulting from the known tendency of smokers to have lower dietary intakes of Zn. The higher Cu concentrations in OC users are discussed in relation to altered Cu metabolism, characterized by increased synthesis of the Cu-binding protein, ceruloplasmin, as an acute-phase antioxidant response to altered lipid profile and increased lipid oxidation.     

Selenium status,plasma zinc,copper, and magnesium in vegetarians

Plasma zinc (Zn), copper (Cu), and magnesium (Mg) concentrations, copper/zinc ratio, and selenium (Se) status were studied in 44 vegetarians (22 males and 22 females) and their age- and sex-matched nonvegetarians in the Bratislava region (Slovakia). Vegetarians had statistically significant lower levels of plasma Zn and Cu than nonvegetarians, which may be the result of lower bioavailability of Zn and Cu from this type of diet. No differences in plasma Mg levels were found between vegetarians and nonvegetarians. Se status, as expressed by plasma and erythrocyte concentrations and plasma and erythrocyte glutathione peroxidase activities (GPx), was significantly lower in vegetarians when compared to nonvegetarians. In the series as a whole, there were significantly higher correlations between plasma and erythrocyte Se concentrations and between plasma and erythrocyte GPx activities. Significant positive correlations were also found between plasma Se concentrations and erythrocyte GPx activities, and between erythrocyte Se concentrations and erythrocyte GPx activities. A vegetarian diet does not provide a sufficient supply of essential antioxidant trace elements, like Zn, Cu, and especially Se. Se supplementation should be recommended to this risk group of the population.     

Electrospray ionization mass spectrometry of zinc, cadmium, and copper metallothioneins: evidence for metal-binding cooperativity

Electrospray ionization (ESI) mass spectra of both well-characterized and novel metallothioneins (MTs) from various species were recorded to explore their metal-ion-binding modes and stoichiometries. The ESI mass spectra of the zinc- and cadmium-binding MTs showed a single main peak corresponding to metal-to-protein ratios of 4, 6, or 7. These findings combined with data obtained by other methods suggest that these MTs bind zinc or cadmium in a single predominant form and are consistent with the presence of three- and four-metal clusters. An unstable copper-specific MT isoform from Roman snails (Helix pomatia) could be isolated intact and was shown to preferentially bind 12 copper ions. To obtain additional information on the formation and relative stability of metal-thiolate clusters in MTs, a mass spectrometric titration study was conducted. One to seven molar equivalents of zinc or of cadmium were added to metal-free human MT-2 at neutral pH, and the resulting complexes were measured by ESI mass spectrometry. These experiments revealed that the formation of the four-metal cluster and of the thermodynamically less stable three-metal cluster is sequential and largely cooperative for both zinc and cadmium. Minor intermediate forms between metal-free MT, Me4MT, and fully reconstituted Me7MT were also observed. The addition of increasing amounts of cadmium to metal-free blue crab MT-I resulted in prominent peaks whose masses were consistent with apoMT, Cd3MT, and Cd6MT, reflecting the known structure of this MT with two Me3Cys9 centers. In a similar reconstitution experiment performed with Caenorhabditis elegans MT-II, a series of signals corresponding to apoMT and Cd3MT to Cd6MT species were observed.     

Serum copper,zinc levels,and copper

Serum copper and zinc levels were determined in 20 healthy women and in 100 women with gynecological tumors. Malignant and benign tumor cases were separated according to their postoperative, histopathological examinations. The stages of malignant and benign tumors were also established histologically. Seventy benign and 30 malignant genital tumors (carcinoma of cervix in situ, cervix, ovary endometrium, and vulva) of the patients were differentiated histopathologically. The serum Cu/Zn ratios of patients were increased significantly from the control group (0.32±0.35) to the benign group (1.22±0.63) and from the benign group to the malignant group (2.24±1.03). Nine of 30 malignant cases were determined as false negative (30%) and 15 of 70 benign cases were determined as false positive (14.2%) according to the serum Cu/Zn ratios of patients. Serum copper levels of 30 malignant and 10 benign tumor cases showed linear correlation with serum ceruloplasmin values.