Participation of metallothionein and superoxide dismutase in the blood of smoking smelters

Objectives

Metallothionein (MT) and two forms of superoxide dismutase (SOD), which are dependent on zinc and copper ions, are involved in defense against the same superoxide anion radicals and are present in extra- and intracellular compartments. The aim of our study was to investigate MT concentration and Cu/Zn SOD activity in the plasma and erythrocyte lysate of the non-smoking and smoking smelters.

Material and Methods

The investigations were performed in the blood of 300 male smelters and 100 non-exposed male subjects. We have measured zinc, copper, malondialdehyde (MDA) and MT concentrations as well as SOD activity.

Results

We have observed an increase of Cu/Zn coefficient and decrease of Zn/Cu coefficient in the serum of smelters in comparison with the non-smoking control group. Concentration of MDA in the plasma of smelters was higher in comparison with its concentration in the non-smoking control group. The plasma and the erythrocyte lysate MT concentration increased significantly in the whole group of smelters as compared to the non-smoking control group. The mean value of MT concentration in plasma of the smoking smelters was above 2-fold higher than in the non-smoking control group. The activity of Cu/Zn SOD in plasma of the smoking and non-smoking smelters was decreased in comparison with the smoking and non-smoking control groups, respectively. The lowest activity of Cu/Zn SOD, about 2–3-fold decreased in comparison with the smoking and non-smoking control groups, was detected in plasma of the smelters. An inverse relationship was observed in the erythrocyte lysate. The highest activity of Cu/Zn SOD was reported in the erythrocyte lysate of the smoking smelters and it was about 2-fold higher than in the non-smoking control group.

Conclusions

In extracellular environment MT plays a crucial role in comparison with the SOD, while in the intracellular compartment Cu/Zn SOD and MT cooperate with each other.     

Analyzed dietary intakes,plasma concentrations of zinc,copper, and selenium,and related antioxidant enzyme activities in hospitalized elderly women.

The purpose of the study was to assess the actual dietary intakes of zinc (Zn), copper (Cu) and selenium (Se) intakes in relation with some indicators of trace element status in a selected group of hospitalized elderly patients.

24 elderly women aged 76-99 years were recruited in the Geriatric Department of the Grenoble University Hospital.

Zn, Cu, and Se dietary intakes were estimated by duplicate portion analysis. Plasma trace element concentrations, Cu-Zn superoxide dismutase (Cu-Zn SOD) and Se glutathione peroxidase (Se GSH-Px) activities were determined in parallel.

Mean daily intakes of Zn (5.6 mg), Cu (0.67 mg), and Se (23 micrograms) were low, in relation with poor energy intake and nutrient densities. Zn and Se levels in plasma were lower and plasma Cu increased compared to reference values obtained from healthy younger subjects. Thirty-eight percent of the elderly patients had plasma Zn concentrations < 10.7 mumol/l, but Cu status appeared adequate as suggested by the lack of decline in Cu-Zn SOD activity. A high proportion of plasma Se concentrations < 0.76 mumol/l and the parallel decrease in erythrocyte and plasma GSH-Px activities suggest a Se deficiency in this population.

Our findings indicate that French hospitalized elderly patients may be at risk of Zn and Se marginal status and present altered antioxidant defenses in relation with low dietary intakes. It underlines the interest of supplementation studies in this population.     

Effects of varying dietary iodine supplementation levels as iodide or iodate on thyroid status as well as mRNA expression and enzyme activity of antioxidative enzymes in tissues of grower/finisher pigs

Purpose

The objective of this study was to investigate the influence of high dietary iodine supply and different iodine sources on thyroid status and oxidative stress in target tissues of the thyroid hormones in fattening pigs.

Methods

Eighty castrates (body weight: 33.3 ± 0.4 kg) were randomly allotted into five different treatments: The control diet contained 150 μg I/kg as KI, the other feeding groups were supplemented with 4,000 μg I/kg (as KI and KIO₃) and 10,000 μg I/kg (as KI and KIO₃), respectively. The mRNA expression levels of sodium/iodide symporter (NIS) and key antioxidant enzymes (Cu/Zn SOD, CAT, GPx) were analyzed in thyroid gland, liver, kidney, muscle, and adipose tissue sampled during slaughter. Furthermore, antioxidant enzyme activities and the effect on lipid peroxidation (MDA) were determined in liver and muscle.

Results

In thyroid gland, a significant downregulation of NIS and Cu/Zn SOD mRNA expression was observed in high-iodine groups. In liver, a source effect on the mRNA expression of Cu/Zn SOD between KI and KIO₃ at 4,000 μg I/kg was shown. In contrast, not SOD but GPx activity was affected by iodine source with strongest downregulation in high KIO₃ group. In muscle, GPx activity was affected by both iodine source and dose, showing stronger downregulation in KI groups. In kidney and adipose tissue, oxidative stress parameters showed no or only unsystematic changes. However, variation in iodine supply had no effect on MDA concentrations.

Conclusions

NIS expression was significantly decreased with increased iodine supplementation, which is to ensure the thyroid gland function. However, the alleviating effect of iodine supplementation observed in antioxidant enzyme mRNA expression and activity did not reflect on the lipid peroxide level.     

Hepatic PKA inhibition accelerates the lipid accumulation in liver

Zinc deficiency can change the concentrations of minerals and trace elements in the body. However, previous studies still had many limitations. To reveal the effects of zinc deficiency on homeostasis of 16 minerals and trace elements. Forty-five rats were divided randomly into three groups: normal zinc diet (30 mg/kg), low zinc diet (10 mg/kg), and pair-fed diet(30 mg/kg). The concentrations of 16 minerals and trace elements in serum, feces, urine, and liver were measured by inductively coupled plasma mass spectrometry. The excretion of 16 elements in urine and feces were calculated and compared. Zinc-deficient rats exhibited significant changes in up to 12 minerals and trace elements. The low zinc diet induced decreased excretion of zinc and concentrations of zinc in serum, feces, urine, and liver. Zinc deficiency increased feces concentrations of Mg, Cu, Se, K, Ag, Fe and Mn; decreased the concentrations of Mg, Cu, Se, K in liver and urine, and a diminished amount of Ag was observed in serum. Decreased urinary concentrations of Zn Ca, Mg, Cu, Se, K, Na, As and Cr, suggested that zinc-deficient rats increased the 9 elements’ renal reabsorption. Decreased concentrations of Ca in liver, urine, and feces, decreased excretion in urine and feces and increased serum total Ca suggested that zinc deficiency increased the redistribution of Ca in serum or other tissues. Zinc deficiency increased excretion of Cu, Se, Fe; and decreased the excretion of other 8 elements except for Ag. Zinc deficiency changed the excretion, reabsorption and redistribution of 12 minerals and trace elements in rats. Our findings are the first to show that zinc deficiency alters the concentrations of Ag, Cr, and As.     

微量元素与乙型病毒性肝炎关系的研究(1)

目的 探讨微量元素与乙型病毒肝炎的关系.方法 用原子吸收分光度计对HBV感染者血清中的微量元素铜、铁、锌、硒进行定,以SPSS9.0forwin进行相应的统计分析.结果 HBV感染者血清Zn低于正常对照组,HBsAg健康携带组血清Se低于对照组.在HBV患者组Cu/Zn、Fe/Zn均高于对照组,具有显着性差异(P<0.01).Logistic回归分析,微量元素Se及Cu/Zn比值进入回归方程.结论 微量元素Zn、Se、Cu、Fe与乙型病毒性肝炎存在密切关系.     

Zinc Supplementation Alters Plasma Aluminum and Selenium Status of Patients Undergoing Dialysis: A Pilot Study

End stage renal disease patients undergoing long-term dialysis are at risk for abnormal concentrations of certain essential and non-essential trace metals and high oxidative stress. We evaluated the effects of zinc (Zn) supplementation on plasma aluminum (Al) and selenium (Se) concentrations and oxidative stress in chronic dialysis patients. Zn-deficient patients receiving continuous ambulatory peritoneal dialysis or hemodialysis were divided into two groups according to plasma Al concentrations (HA group, Al > 50 μg/L; and MA group, Al > 30 to ≤ 50 μg/L). All patients received daily oral Zn supplements for two months. Age- and gender-matched healthy individuals did not receive Zn supplement. Clinical variables were assessed before, at one month, and after the supplementation period. Compared with healthy subjects, patients had significantly lower baseline plasma Se concentrations and higher oxidative stress status. After two-month Zn treatment, these patients had higher plasma Zn and Se concentrations, reduced plasma Al concentrations and oxidative stress. Furthermore, increased plasma Zn concentrations were related to the concentrations of Al, Se, oxidative product malondialdehyde (MDA), and antioxidant enzyme superoxide dismutase activities. In conclusion, Zn supplementation ameliorates abnormally high plasma Al concentrations and oxidative stress and improves Se status in long-term dialysis patients.     

Magnesium and trace element intake after a lifestyle intervention

Objective

Observational studies suggest that some trace elements and magnesium (Mg) improve glucose metabolism, markers of inflammation, and oxidative stress, but supplementation studies have yielded inconsistent results. Our objective was to evaluate whether a lifestyle intervention trial, aimed at reducing total and saturated fat and increasing fiber intake, can affect also the intake of selenium (Se), zinc (Zn), copper (Cu), chromium (Cr), and Mg.

Methods

Dietary intake of Se, Cr, Zn, Cu, and Mg was evaluated at baseline and at the end of a lifestyle intervention trial performed in 335 dysmetabolic adults.

Results

At baseline, trace element and Mg intake in the intervention (n = 169) and control (n = 166) groups of the trial were not significantly different. The former significantly increased their intake of Se, Mg, and Cr, while the latter reduced the intake of Mg, Zn, and Cr. Between-group differences were significant for Mg, Cr, and Se.

Conclusion

Healthier lifestyle recommendations might improve the pattern of micronutrient and Mg intake, which might play an independent role in ameliorating some metabolic, inflammatory, and oxidative markers.     

HBV感染者血浆微量元素浓度与氧化应激的关系

目的:探讨HBV感染者血浆微量元素浓度与氧化应激的相关关系。方法:测定了52例HBV感染者和20例健康对照血浆微量元素(铜、锌、铁和硒)和氧化应激参数(谷胱苷肽、丙二醛和总抗氧化力)水平。结果:HBV感染者血浆微量元素Fe(F=38.845,P=0.000)、Cu(F=21.284,P=0.000)、Zn(F=44.443,P=0.000)和Se(F=66.710,P=0.000)均与健康对照存在明显的统计学差异。Pearson相关分析显示:HBV感染者微量元素Zn和Se间存在正相关关系(r=0.414,P=0.002);Fe与Zn(r=-0.039,P=0.782)、Cu(r=-0.177,P=0.209)或Se(r=-0.081,P=0.566)之间存在负相关关系,但无统计学差异。Se与脂质过氧化终末产物MDA之间存在正相关关系(r=0.319,P=0.021);Cu与氧化应激参数GSH之间存在负相关关系(r=-0.583,P=0.000)。结论:HBV感染者血中微量元素的变化可能存有交互作用,且与机体氧化应激反应密切相关。     

Copper, iron, zinc, and selenium dietary intake and status of Nepalese lactating women and their breast-fed infants

The dietary intake of copper, iron, zinc, and selenium of 26 Nepalese lactating mothers was estimated from chemical analysis of 24-h food and beverage composites. Fasting blood and milk samples were obtained from the mothers and blood samples were obtained from the infants. The Nepalese mothers consumed significantly more Cu, significantly less Fe and Se, and similar amounts of Zn as compared with American lactating women. Blood Fe status indices and plasma concentrations of Cu, Zn, and Se were lower in the Nepalese mothers than in the American mothers. These lower values may in part be related to the high neutral detergent fiber and phytate content of the Nepalese diet, which could make these minerals less available for absorption. The high exposure to infections in Nepal may also depress Fe status indices and plasma Zn concentrations. The lower dietary Se intake of the Nepalese mothers was reflected in lower milk concentrations.     

Association between GPx1 Pro198Leu polymorphism, GPx1 activity and plasma selenium concentration in humans

Background

Glutathione peroxidase 1 (GPx1) is an antioxidant selenoenzyme that protects the cells against reactive oxygen species. Its activity depends on the concentration of selenium (Se) which is present in the active centre of the enzyme. The genetic polymorphism of GPx1 encoding gene (GPx1) associated with the proline (Pro) to leucine (Leu) change at codon 198 is supposed to be functional. An in vitro study performed on human breast carcinoma cell line showed that GPx1Leu allele was associated with a lower responsiveness of the enzyme to Se added to the culture medium. Some authors observed a decrease in GPx1 activity associated with GPx1 Leu allele in humans; however, there were no findings on how GPx1 activity changes with Se concentration in individuals with different GPx1 genotypes.

Aim of the study

To assess whether GPx1 activity that depends on the Se status may be influenced by GPx1 polymorphism through studying this relationship in the blood of healthy individuals.

Methods

The association between the Se status, GPx1 activity and GPx1 genotype was assessed in 405 individuals of Polish origin. GPx1 activity in red blood cells was measured by the spectrophotometric method by Paglia and Valentine, using t-butylhydroperoxide as the substrate. Plasma Se concentration was measured using graphite furnace atomic absorption spectrometry. GPx1 Pro198Leu polymorphism was determined with the Molecular Beacon Real-Time PCR assay.

Results

In the subjects examined, the mean plasma Se concentration was 54.4 ± 14.2 mcg/L. The mean GPx1 activity was 15.1 ± 4.7 U/g Hb. No difference regarding both the parameters was found between individuals with different GPx1 genotype. However, the association between GPx1 activity and Se concentration, analyzed separately for each genotype group, was not the same. The correlation coefficients amounted to r = 0.44 (p < 0.001) for Pro/Pro, r = 0.35 (p < 0.001) for Pro/Leu and r = 0.25 (p = 0.45) for Leu/Leu group, which indicates that the correlation strength was as follows: Pro/Pro > Pro/Leu > Leu/Leu. Notably, statistically significant difference in this relationship (analyzed as difference between correlation coefficients for linear trends) was found between genotypes Pro/Pro and Leu/Leu (p = 0.034).

Conclusions

The findings of the present study provide evidence for the hypothesis based on in vitro studies which assumes that GPx1 Pro198Leu polymorphism has a functional significance for the human organism and that this functionality is associated with a different response of GPx1 activity to Se. They also point to the importance of the genetic background in the assessment of the Se status with the use of selenoprotein biomarkers such as GPx1 activity.     

微量元素与丙型病毒性肝炎的研究(3)

目的探讨微量元素与丙型病毒肝炎的关系。方法用原子吸收分光光度计测定HCV感染者血清中的微量元素Cu、Fe、Zn、Se,以SPSS forwindows9.0进行统计分析。结果抗-HCV阳性组及HCV患者组血清Zn低于正常对照组,经统计学检验具有高度显着性差异(P<0.001);抗-HCV阳性组血清Cu高于对照组,差异有高度显着性差异(P<0.001).丙肝患者组血清Se低于健康对照组,有显着性差异(P<0.001).抗-HCV阳性组及丙肝患者组Cu/Zn、Fe/Zn均高于对照组,有高度显着性差异(P<0.01).Logistic回归分析,抗-HCV阳性组微量元素Cu、Zn进入回归方程,丙肝患者组微量元素Se进入回归方程。结论微量元素Zn、Se、Cu、Fe与病毒性肝炎存在密切关系,微量元素Cu、Zn对抗-HCV阳性组影响最大,微量元素Se对丙肝患者影响最为显著。     

Trace elements and sperm parameters in semen of male partners of infertile couples

OBJECTIVE: The relationships between element concentrations and sperm parameters in semen samples were investigated. METHODS: Semen samples (n = 113) were donated voluntarily by male partners of infertile couples. The concentrations of fourteen elements (Na, K, P, Ca, Zn, Mg, Fe, Cu, Se, Mn, Sn, Co, Ni, and Cd) in semen were determined by atomic absorption spectrometry, fluorometry, or colorimetry. Element concentrations in seminal plasma and in sperm were also measured. RESULTS: Element concentrations in semen were in the order Na > P, K > Ca > Zn > Mg > > Fe> Cu, Se > Mn > Sn, Ni, Co, Cd. When the samples were divided into two groups in terms of sperm concentration and number, the Se concentration in semen with normal parameter values (sperm concentration > or = 20 x 10(6) and sperm number > or = 40 x 10(6)), 99.4 +/- 37.4 ng/ml, was higher than that in semen with abnormal parameter values (sperm concentration < or = 20 x 10(6) and/or sperm number < or = 40 x 10(6)), 72.1 +/- 33.9 ng/ml (p < 0.001). A clearer positive correlation between the Se concentration and the sperm concentration was observed in the sperm portion (r = 0.853, p < 0.001) than in semen (r = 0.512, p < 0.001) and seminal plasma (r = 0.292, p = 0.003). Statistically significant correlations were also observed between the concentration of Se, P, Zn, Cu, Fe, or Mn in semen, the sperm portion or seminal plasma and the sperm concentration, semen volume or abnormal morphology, although correlation coefficients were small. CONCLUSION: Among biologically essential elements in semen of infertile males, Se was a good indicator of sperm concentration; however, other trace elements did not indicate clear relationships between their concentrations and sperm parameters.     

微量元素与甲型病毒性肝炎关系的研究(2)

目的探讨微量元素与甲型病毒性肝炎的关系。方法采用1:1配对病例对照,用原子吸收法对HAV感染者血清中的微量元素铜铁锌硒进行测定,并做相应的统计分析。结果HAV患者血清微量元素Zn、Se含量降低,微量元素Fe含量升高。Logistic回归分析表明,Zn是HAV-IgG阳性者向HAV患者转化的重要影响因素,Fe/Zn比值是HAV患者的重要影响因素。结论血清微量元素与HAV存在密切关系:Fe、Zn、Se微量元素是HAV的重要影响因素,在甲型病毒性肝炎的预防诊断及治疗中具有重要作用。     

微量元素与戊型病毒性肝炎的研究(4)

目的：探讨微量元素与戊型病毒性肝炎的关系。方法：用原子吸收分光光度计对HEV感染者血清中的微量元素Cu、Fe、Zn、Se进行测定，以SPSS for win9.0进行相应的统计分析。结果：抗－HEV阳性组血清Zn、Se低于对照组（P＜0．001），血清Fe高于对照组（P＜0．001）。戊型病毒性肝炎患者组血清Zn、Se低于对照组（P＜0．001），血清Fe低于对照组（P＜0．05）。抗－HEV阳性组Cu/Zn、Fe/Zn比值均高于对照组，有显著性差异（P＜0．001）。戊型病毒性肝炎患者组Cu/Zn、Fe/Zn比值高于对照组（P＜0．05）。Logistic回归分析，抗－HEV阳性组微量元素Se及Cu/Zn、Zn/Se比值进入回归方程。结论：微量元素Zn、Se对HEV感染者的影响最为显著。     

Case study of temporal changes in maternal dietary intake and the association with breast milk mineral contents

Minerals play important roles in infant growth and development, even though they only make up to 0.2 g% of the mature breast milk contents. Limited studies examined the association between maternal dietary intake and breast milk mineral contents in a temporal manner. Twenty Malaysian Malay postpartum mothers were recruited by either convenience or snow balling sampling from the urban lower middle income residential areas. Dietary intake of the subjects was obtained by 24-hour recall during each breast milk collection. Adequacy of maternal mineral intake was compared with the latest Recommended Nutrient Intake for Malaysia. Each of the subject provided breast milk samples for three times (T1, T2, and T3) at consecutive 2-week intervals. Breast milk concentrations of selected macro- and micro-minerals, including Ca, P, K, Na, Mg, Fe, Zn, Cu, Mn, Se, I, Cr and Mo were determined by inductively coupled plasma mass spectrometry (ICP-MS). Subjects were aged 31.4 ± 6.1 years with a majority (60 %) having post-secondary school/ college education. While maternal intake of macro-minerals, Ca, P, K and Mg, did not display a significant temporal changes from T1 to T3, the intake of micro- minerals, Cu, Mn and I decreased significantly over time from T1 to T3. Breast milk K, Fe, Zn and Cu concentrations showed a significant decreased with the progression of lactation from transitional (2–3 weeks) to established stage (>8-12 weeks). Significant correlations were established between maternal intake of K, Na, Fe and Se and their respective concentrations in breast milk in the present study. This case study revealed an inadequate maternal intake of several key micro- minerals (Cu, Mn, I) among the postpartum Malay mothers and a decreasing concentrations of certain essential minerals (K, Fe, Zn and Cu) in breast milk with lactation stage.     

骨肿瘤患者血清组织中微量元素含量研究

瘤患者和３５例健康人对照组血清和组织中微量元素含量。结果提示，骨肉瘤组血清中Ｃｕ、Ｃｕ／Ｚｎ含量比对照组高，Ｚｎ、Ｆｅ、Ｓｅ含量比对照组低；在组织中Ｃｕ、Ｚｎ、Ｆｅ含量高于对照组，Ｃａ含量则低于对照组．上述均有统计学显著性差异（Ｐ＜０．０５～０．００１）。     

Genetic Effects on Toxic and Essential Elements in Humans: Arsenic,Cadmium, Copper,Lead, Mercury,Selenium, and Zinc in Erythrocytes

Background and objectives

An excess of toxic trace elements or a deficiency of essential ones has been implicated in many common diseases or public health problems, but little is known about causes of variation between people living within similar environments. We estimated effects of personal and socioeconomic characteristics on concentrations of arsenic (As), cadmium (Cd), copper (Cu), mercury (Hg), lead (Pb), selenium (Se), and zinc (Zn) in erythrocytes and tested for genetic effects using data from twin pairs.

Methods

We used blood samples from 2,926 adult twins living in Australia (1,925 women and 1,001 men; 30–92 years of age) and determined element concentrations in erythrocytes by inductively coupled plasma-mass spectrometry. We assessed associations between element concentrations and personal and socioeconomic characteristics, as well as the sources of genetic and environmental variation and covariation in element concentrations. We evaluated the chromosomal locations of genes affecting these characteristics by linkage analysis in 501 dizygotic twin pairs.

Results

Concentrations of Cu, Se, and Zn, and of As and Hg showed substantial correlations, concentrations of As and Hg due mainly to common genetic effects. Genetic linkage analysis showed significant linkage for Pb [chromosome 3, near SLC4A7 (solute carrier family 4, sodium bicarbonate cotransporter, member 7)] and suggestive linkage for Cd (chromosomes 2, 18, 20, and X), Hg (chromosome 5), Se (chromosomes 4 and 8), and Zn {chromosome 2, near SLC11A1 [solute carrier family 11 (proton-coupled divalent metal ion transporters)]}.

Conclusions

Although environmental exposure is a precondition for accumulation of toxic elements, individual characteristics and genetic factors are also important. Identification of the contributory genetic polymorphisms will improve our understanding of trace and toxic element uptake and distribution mechanisms.     

Selenium,Copper, Zinc Concentrations and Cu/Zn,Cu/Se Molar Ratios in the Serum of Patients with Acute Ischemic Stroke in Northeastern Poland—A New Insight into Stroke Pathophysiology

Background: In recent years, trace elements (TEs) have gained considerable attention in the course of treatment and diagnosis of ischemic stroke. The purpose of the conducted research was to determine the trace mineral status (Se, Cu, Zn, Cu/Zn ratio, and Cu/Se ratio) in patients with acute ischemic stroke compared to the population of healthy people in the northeastern region of Poland. Materials and methods: 141 patients with acute ischemic stroke (AIS) and 69 healthy control subjects were examined. The serum concentrations of mineral components were assessed by the atomic absorption spectrometry method. Clinical parameters were updated based on medical records. Results: The serum Se and Zn concentrations were significantly decreased (p < 0.0001; p < 0.0001) in patients with AIS compared with healthy control subjects. However, no significant differences were revealed in terms of the serum Cu concentration (p = 0.283). As expected, we found that the serum Cu/Zn and Cu/Se molar ratios were significantly higher (p = 0.001; p < 0.0001) in patients with AIS compared with healthy control subjects. Conclusions: Disturbed metal homeostasis is a significant contributor to AIS pathogenesis. Furthermore, marked disruption of the serum Cu/Zn and Cu/Se molar ratios could serve as a valuable indicator of AIS patients’ nutritional status and oxidative stress levels.     

Antioxidant activity of melatonin in diabetes in relation to the regulation and levels of plasma Cu,Zn, Fe,Mn, and Se in Zucker diabetic fatty rats

ObjectiveTo study the antioxidant activity of melatonin in diabetes in relation to the regulation and levels of plasma copper (Cu), zinc (Zn), iron (Fe), manganese (Mn), and selenium (Se) in Zucker diabetic fatty (ZDF) and lean (ZL) rats.MethodsAt 6 wk of age, both ZDF (n = 30) and ZL (n = 30) animals were subdivided into three groups: control (C) (n = 10), vehicle (V) (n = 10), and melatonin-treated (M) (10 mg/kg/d; n = 10) rats for a 6-wk period. At the end of treatment period, plasma mineral levels were measured by flame (Cu, Zn, and Fe), electrothermal (Mn), and hydride generation (Se) atomic absorption spectrometry.ResultsZDF rats had significantly higher Cu, Fe, and Mn plasma levels than did ZL rats (P < 0.05). No significant differences were found between control and vehicle groups (P > 0.05). Melatonin treatment did not influence plasma levels of these antioxidant minerals (Cu, Zn, Fe, and Mn) in ZDF groups (M-ZDF versus C-ZDF group) and ZL (M-ZL versus C-ZL group) rats with the exception of Zn, whose mean plasma level was lower in the M-ZL versus C-ZL group. However, plasma Se levels increased significantly (P < 0.05) after melatonin supplementation in both groups (M-ZDF and M-ZL).ConclusionThe higher mean plasma Cu, Fe, and Mn levels in the ZDF group are related to the enhanced oxidative stress in diabetes and obesity. Melatonin administration significantly enhanced plasma Se levels in both groups (M-ZDF and M-ZL). This is the first study to report that melatonin treatment increases plasma Se levels.     

Trace element status of children with PKU and normal children

The trace mineral (chromium, copper, iron, selenium, and zinc) status of 10 children (4 to 13.8 years) with phenylketonuria (PKU) and 9 normal children (6.5 to 15.9 years) was assessed. The children with PKU were treated with a phenylalanine-free L-amino acid mix that supplied the following percentages (mean +/- standard deviation) of total daily intake: energy, 45 +/- 13; protein, 75 +/- 11; copper (Cu), 62 +/- 10; iron (Fe), 82 +/- 7; selenium (Se), 40 +/- 20; and zinc (Zn) 87 +/- 8. Diet records and blood samples were collected from each subject. Children with PKU had significantly greater mean intakes of Cu, Fe, and Zn than normal children. Mean serum Cu, Fe, and Zn concentrations of the children with PKU and normal children were not different despite significantly greater intakes by the children with PKU. Normal children had a significantly greater mean serum Se concentration and a mean blood chromium concentration 1.6 times that of children with PKU. Individuals whose primary source of protein is an elemental diet are especially at risk for multiple trace mineral deficiencies. Manufacturers of chemically defined medical foods should evaluate composition, specifically molar ratios between minerals, as a basis for product formulation.