Effects of zinc,selenium, and calcium on the nephrotoxicity of cadmium in primary cultures of rat renal proximal epithelial cells

The influence of essential metals, like zinc, selenium, and calcium, on the nephrotoxicity of cadmium was studied in primary cultures of rat proximal tubular cells. Damage to kidney cells was assessed by measuring the release of lactate dehydrogenase (LDH), γ-glutamyltranspeptidase (GTP), and β-N-acetylglucosaminidase (NAG) from cells into the medium and the cellular concentration of protein. Incubation with 200 μM cadmium in the presence of equivalent molar or lower concentrations of zinc and selenium showed greater release of LDH and NAG than cadmium alone, indicating an enhanced effect. However, metallothionein (MT) induced by pretreatment with a nontoxic concentration of zinc decreased significantly the release of enzyme from cells and elevated cellular protein levels in response to MT levels. MT provided partial protection against the nephrotoxicity of cadmium. Decreased calcium levels in the incubation medium also resulted in markedly increased release of LDH and NAG from cells exposed to cadmium and reduced cellular protein levels. These findings suggest that variations in zinc and calcium intake may affect the development of cadmium-induced renal dysfunction.     

Protective effect of zinc on cadmium-induced micronuclei in V79 cells

The induction of micronuclei (MN) in mitotically active cells has been widely used and promoted as a biological marker of exposure to environmental toxins. In our study the effect of zinc on cadmium genotoxicity was investigated in V 79 cells. The results indicate that cadmium chloride exposure for 24 h increased micronucleus frequency and the percentage of binucleated cells in dose-dependent manner. At the highest concentration of cadmium (50 microM Cd) 23 MN were found in 1000 cells. The protective effect of zinc on cadmium genotoxicity was investigated at lower concentrations (5-25 microM CdCl2). At 50 microM Cd, the number of MN increased significantly (16 MN).     

Development of nutritious rice with high zinc/selenium and low cadmium in grains through QTL pyramiding

Enriching zinc (Zn) and selenium (Se) levels, while reducing cadmium (Cd) concentration in rice grains is of great benefit for human diet and health. Large natural variations in grain Zn, Se, and Cd concentrations in different rice accessions enable Zn/Se‐biofortification and Cd‐minimization through molecular breeding. Here, we report the development of new elite varieties by pyramiding major quantitative trait loci (QTLs) that significantly contribute to high Zn/Se and low Cd accumulation in grains. A chromosome segment substitution line CSSL^GCC7 with the PA64s‐derived GCC7 allele in the 93‐11 background, exhibited steadily higher Mn and lower Cd concentrations in grains than those of 93‐11. This elite chromosome segment substitution line (CSSL) was used as the core breeding material to cross with CSSLs harboring other major QTLs for essential mineral elements, especially CSSL^GZC6 for grain Zn concentration and CSSL^GSC5 for grain Se concentration. The CSSL^GCC7+GZC6 and CSSL^GCC7+GSC5 exhibited lower Cd concentration with higher Zn and Se concentrations in grains, respectively. Our study thus provides elite materials for rice breeding targeting high Zn/Se and low Cd concentrations in grains.     

Changes in selenium, zinc, copper and cadmium contents in human milk during the time when selenium has been supplemented to fertilizers in Finland

Sodium selenate has been supplemented to all agricultural fertilizers used in Finland since 1984. We followed the changes in selenium, cadmium, zinc and copper content in Finnish human milk between the years 1987 and 1993-1995. A total of 257 milk samples was collected, four weeks after delivery, in two areas: In Helsinki, an urban area, and in Kuopio, a rural area, where elevated copper concentrations have been found in the bedrock. Direct atomic absorption spectrophotometric methods without digestion were used for the analyses. The dependence of trace element content on study time, living area, smoking habits, fish eating frequency, and parity of mothers was studied by analysis of covariance. Inter-element correlations and correlations with mothers' age and fat content in milk were studied by partial correlation. Significant increases were observed in mean selenium (16.4 microg/l and 18.9 microg/l, p < 0.001) and in fat contents (3.4% and 4.0%, p < 0.001), whereas significant decreases were seen in mean zinc (3.00 mg/l and 1.47 mg/l, p < 0.001), copper (0.52 mg/l and 0.43 mg/l, p < 0.001) and cadmium contents (0.095 microg/l and 0.062 microg/l, p < 0.01). In 1987, zinc had a positive correlation with copper and fat. Copper correlated inversely with the mothers' age. In 1993-1995, selenium correlated positively with copper, and zinc correlated inversely with mothers' age. Mothers living area had an effect on copper content in milk. Our results confirm that selenium supplementation to fertilizers in Finland has increased the selenium level in human maternal milk and most likely it also has an effect on the zinc and copper concentrations in maternal milk.     

Effects of nutrient solution zinc activity on net uptake,translocation, and root export of cadmium and zinc by separated sections of intact durum wheat (Triticum turgidum L. var durum) seedling roots

Cd accumulation in durum wheat presents a potential health risk to consumers. In an effort to understand the physiological mechanisms involved with Cd accumulation, this study examined the effects of Zn on Cd root uptake and phloem translocation in a split– root system. Durum wheat seedlings were grown in chelate-buffered nutrient solution with intact root systems divided into two sections. Each root section grew in a separate 1 l pot, one of which contained 0.2 μM CdSO₄. In addition, each two-pot system contained ZnSO₄ in the following combinations (in μm) (for -cd root system: +cd root system): 1:1, 1:10, 10:1,10:10, 1:19, and 19:1. Harvested plant material was analyzed for Cd and Zn. In addition, rates of Cd and Zn net uptake, translocation to the shoot, and root export (translocation from one root segment to the other) between days 8 and 22 were calculated. Results show that Zn was not translocated from one root section to its connected root section. Uptake rates of Cd increased as solution Zn concentrations increased. Cd translocation from one root section to the other decreased significantly when the Zn concentration in either pot was greater than 1 μM. These results show the potential of Zn to inhibit movement of Cd via the phloem, and suggests that providing adequate Zn levels may limit phloem loading of Cd into wheat grain. Increasing the rhizosphere activity of Zn²⁺ in Cd-containing soils may therefore result in reduced Cd accumulation in grain even while net Cd uptake is slightly enhanced. This revised version was published online in June 2006 with corrections to the Cover Date.     

Effect of zinc on cadmium influx and toxicity in cultured CHO cells

Addition of zinc lowers the toxicity level of cadmium in cultured CHO cells. Cell survival and protein synthesis were used to measure the cellular toxicity of cadmium.¹⁰⁹Cd was used to measure cadmium uptake by the cells. The results suggest that these class IIB transition metals, zinc and cadmium, share a common transport mechanism. Thus, the antagonism appears to involve a reduction in the influx of cadmium due to the presence of zinc.     

Louis-Bar syndrome: spontaneous and induced chromosomal aberrations in lymphocytes and micronuclei in lymphocytes,oral mucosa and hair root cells

Summary Louis-Bar (L-B) syndrome, also called ataxia-telangiectasia, is cytogenetically characterized by an increased frequency of spontaneous and induced chromosomal aberrations (CA) in cultured lymphocytes and skin fibroblasts. However, it is not yet clear whether the chromosomal instability is also present in uncultured cells. The spontaneous and bleomycin-induced CA in peripheral lymphocytes of 8 L-B patients were evaluated. The micronucleus test was also performed, for the first time in lymphocytes by the cytokinesis-block method, and in uncultured cells of the oral cavity and hair root. The spontaneous frequency of CA and micronuclei in lymphocytes was about 3 times higher in L-B patients than in controls, these two cytogenetic parameters being highly correlated. Moreover, the induction by bleomycin of CA was higher in patients than in controls. The micronuclei in buccal and hair root cells of patients were normal. It remains to be determined whether the different responses obtained with cultured and uncultured cells are the result of the different L-B gene expression of chromosomal instability or whether they arise because of a particular cell sensitivity to culture conditions. The spontaneous and induced CA in lymphocytes of heterozygotes cultured in the presence of L-B serum were studied to evaluate a possible increased sensitivity of heterozygotes to a possible diffusible clastogenic factor present in the plasma of L-B patients. We could not demonstrate the presence of any factor that enhances CA in normal subjects or in heterozygote carriers.     

Concentrations of cadmium,lead, selenium,and zinc in human blood and seminal plasma

The concentrations of cadmium, lead, selenium, and zinc in blood and seminal plasma were determined in 76 Singapore males. Except for zinc, the concentrations were generally higher in blood than in seminal plasma (cadmium, 1.31 μg/L vs 0.61 μg/L; lead, 82.6 μg/L vs 12.4 μg/L, and selenium, 163.6 μg/L vs 71.5 μg/L). The mean concentration of zinc in seminal plasma was more than 30 times higher than in blood (202 mg/L vs 6.2 mg/L). Significant positive correlations were found between the concentrations in blood and seminal plasma for the two essential trace elements: selenium (r=0.45,p<0.001) and zinc (r=0.25,p<0.05). However, no relationships were found between the concentrations in blood and seminal plasma for two toxic metals (cadmium and lead). Significant inverse correlations were observed between Cd and Zn (r=−0.40,p<0.01), and Pb and Se (r=−0.32,p<0.05) in blood, whereas significant positive correlations were noted between Cd and Se (r=0.45,p<0.01), Cd and Zn (r=0.35,p<0.05), and Se and Zn (r=0.57,p<0.001) in seminal plasma. The physiological significance of these relationships are also discussed in this paper.     

一种由粉红粘帚霉引起的青稞根腐病

[背景]根腐病在青稞生产中的危害日趋严重,阻碍了青稞根腐病的有效防控及青海省青稞产业的发展。然而人们对青稞根腐病的研究甚少且病原菌不详。[目的]明确青稞根腐病发生的危害、病原及致病性,为青稞根腐病的防控提供理论依据。[方法]采用常规的组织分离法分离青稞根腐病病原,通过形态鉴定与分子鉴定结合的方法对病原进行鉴定,并采用烧杯水琼脂法测定其致病性。[结果]共分离得到4株青稞根腐病病原菌,鉴定为Clonostachys rosea,有较强的致病性且致病性差异显著,经柯赫氏法则验证为青稞根腐病病原菌,并且是一种新的青稞根腐病病原,该类根腐病也是一种新的根腐类病害,在国内外属首次发现。[结论]Clonostachys rosea可引起青稞根腐病且致病性强。     

镉胁迫对秋华柳根系活力及其Ca、Mg、Mn、Zn、Fe积累的影响

以秋华柳为试验材料,采用水培试验方式,设置CK(0 mg·L^-1 Cd²⁺)、T₁(2 mg·L^-1 Cd²⁺)、T₂(10 mg·L^-1Cd²⁺)、T₃(20 mg·L^-1Cd²⁺)、T₄(50 mg·L^-1Cd²⁺)5种镉处理浓度,通过对秋华柳根系活力,叶、韧皮部、木质部和根部的镉含量,以及Ca、Mg、Mn、Zn、Fe 5种常规金属元素含量的测定,研究了不同浓度镉胁迫下秋华柳根系活力及Ca、Mg、Mn、Zn、Fe 等金属元素含量的变化.结果表明:1)秋华柳根系活力随着镉处理浓度的增加而逐渐下降,当镉浓度≥10 mg·L^-1时,根系活力与对照相比显著下降.2)随着镉处理浓度的增加,秋华柳叶中Fe的积累受到显著抑制;韧皮部Mg、Mn、Fe的积累受到显著抑制;木质部Ca、Mg、Mn、Zn、Fe 等5种常规金属元素的积累无显著性差异;根部5种常规金属元素的吸收和积累受到显著抑制,表现出镉对其他金属元素积累的拮抗作用.其中,50 mg·L^-1的镉胁迫下,根部Zn的积累量降幅最大,受Cd的抑制最明显.3)各处理组Fe的转移系数与对照相比均无显著性差异;Ca、Mg、Mn、Zn的转移系数均高于对照,且在一定的镉处理水平上差异显著.4)镉胁迫下,秋华柳根部镉的积累量与Ca的积累量呈显著负相关,与其他4种常规金属元素的积累量呈极显著负相关,说明根部常规金属元素的变化可作为秋华柳受镉毒害程度的指示之一.     

Changes in serum selenium, copper, zinc levels and Cu/Zn ratio in patients with pulmonary tuberculosis during therapy

The effectiveness and success of antituberculosis therapy is mainly measured by its ability to identify the organism in the sputum. In certain cases, available tuberculosis tests are not satisfactory and do not provide enough information on the effectiveness of antituberculosis therapy. Copper (Cu), zinc (Zn), and selenium (Se) are the essential elements that play a crucial role in the immune system. The serum levels of these elements vary in many diseases including tuberculosis. In this study, we investigate whether the serum levels of Cu, Zn, and Se change during antituberculosis therapy. We have included 22 pulmonary tuberculosis cases that were newly diagnosed with positive sputum and 18 healthy subjects. At the beginning and 2 mo after therapy, serum levels of Cu, Zn, and Se were measured by atomic absorption spectrometry. Despite Se and Cu levels not being affected during the treatment, we found that there was a significant increase in the levels of Zn and a decrease in the Cu/Zn ratio. Serum Zn levels and the Cu/Zn ratio could be used as a valuable laboratory tool for the clinicians to assess response to therapy or effectiveness of the ongoing antituberculosis therapy.     

Zinc protection against cadmium-induced infertility in female rats. Effect of zinc and cadmium on the progesterone production of cultured granulosa cells

Adult female rats were treated subcutaneously (sc) with zinc chloride (ZnCl, 10 or 20 mg kg body weight, bw) four times during two ovarian cycles. The third injection was accompanied by cadmium chloride (CdCl) administration sc (2.5, 5 and 10 mg kg bw). The fourth zinc (Zn) treatment was followed by mating.ZnCl (20 mg kg) itself impaired fertility by 20%, while CdCl dose-dependently blocked the receptivity of female rats. In combination with 2.5 and 5 mg kg CdCl the metal salts decreased fertility in an additive fashion, whereas at the highest CdCl dose (10 mg kg) a marked ameliorating effect of ZnCl (10 and 20 mg kg) on cadmium (Cd)-caused sterility was observed.In the pregnant animals apart from the higher Cd-induced blood progesterone levels and reduced body weight gain of dams, no significant treatment-related maternal and fetal effects could be observed. ZnCl (10 to 80 m) and CdCl (10 to 80 m) were added to the culture medium of ovarian granulosa cells. CdCl suppressed follicle-stimulating-hormone- (FSH-) and cAMP-stimulated progesterone accumulation. No protective effect of Zn against Cd-induced drop in progesterone production could be seen, while Zn by itself induced a significant increase in FSH-supported progesterone synthesis.In conclusion, while Zn protected against Cd-induced sterility in vivo, it failed to counteract the direct effect of Cd on steroid biosynthesis. The data indicate that Zn protection does not take place at the level of ovary. Moreover, Zn and Cd seem to affect FSH-stimulated progesterone production by different mechanisms.     

Distributional pattern of zinc,cadmium, mercury,and selenium in livers of Hooded Seal (Cystophora cristata)

The liver of Hooded Seal (Cystophora cristata) consists of six lobes of unequal sizes. Extensive sampling by means of cutout samples covering the depth horizon 2–30 mm below liver surface indicates that the liver may be considered homogeneous as to concentrations of zinc, cadmium, mercury, and selenium (residuals of overall mean compatible with normality, the all-organ variance negligibly in excess of within-lobe variance). Mercury and selenium are present in equimolar concentrations. Cutout samples have mercury and selenium concentrations respectively c. 17 and 8% (dry weight basis) above those of homogenates of the same lobe. The apparent dilution of mercury and selenium is tentatively attributed to coarse blood vessels and bile ducts abundantly present in the homogenate but almost absent from the cutouts.     

Serum and hair levels of zinc, selenium, iron, and copper in children with iron-deficiency anemia

In the present study, the serum and hair levels of zinc, selenium, and copper were determined in children with iron-deficiency anemia (IDA). A total of 52 anemic children aged 1–4 yr constituted the study group. Fortysix healthy children acted as controls. The copper and zinc levels were measured with an atomic absorption spectrophometer. Serum and hair selenium was determined by a spectroflourometric method. The serum zinc and selenium concentrations in the IDA group were found to be significantly lower and serum copper significantly higher than those in the controls (p<0.05). Lower iron, zinc, and selenium concentrations (p<0.001) but not copper were found in hair (p>0.05).     

Idiopathic scoliosis and concentrations of zinc,copper, and selenium in blood plasma

The concentration of zinc, copper, selenium, albumin, and ceruloplasmin in blood plasma and the activity of superoxide dismutase and glutathione peroxidase in erythrocytes were determined in a set of patients with idiopathic scoliosis (n=51). A significant decrease of selenium concentration (0.50±0.16 μmol/L) was found when compared with a control group (0.69±0.07 μmol/L) (p<0.01). The same levels of significance were found out for selenium levels corrected for albumin content. In a group of patients with a curvature over 45° indicated for a surgical correction, the average plasma concentrations of selenium were significantly lower (p<0.05) in comparison with a group of patients with a curvature below 45° treated conservatively. The GSH-Px activity in erythrocytes was the same in both sets. In comparison with the controls, no significant differences were revealed in all of the other parameters. The detection of the decreased blood plasma concentration of selenium has suggested possible disturbance of well-proportioned distribution and of general optimal availability of selenium in the organism of patients with idiopathic scoliosis with likely effects on the process of synthesis and maturation of collagen affecting the axial skeleton stability.     

Copper,zinc, and selenium in whole blood and thyroid tissue of people with various thyroid diseases

We investigated the possible differences among the concentrations of copper, zinc, and selenium, and their mutual relations in the whole blood and thyroid tissue of patients with various thyroid disorders. Trace elements were determined by total-reflection X-ray fluorescence. The mean levels of these metals in blood as well as the mean Cu/Zn, Cu/Se, and Zn/Se ratios in the patients with thyroid cancer were significantly higher that in other patients and the control groups. However, the mean Zn and Se concentrations in the thyroid cancer tissue were significantly lower than in the thyroid tissue of other patients. In addition, the mean Cu/Zn and Cu/Se ratios in the thyroid cancer tissue were significantly higher than in the patients with other thyroid diseases. We confirm that the highest levels of copper and zinc as well as the Cu/Zn, Cu/Se, and Zn/Se ratios in the whole blood of the patients with thyroid cancer may suggest the progression of the proliferation process in the thyroid gland. We suggest that the low concentrations of zinc and selenium in the thyroid tissue confirm their participation in the carcinogenic process.     

In vitro assessment of target cell specificity in cadmium carcinogenesis: Interactions of cadmium and zinc with isolated interstitial cells of the rat testes

Summary Cadmium (Cd) induces testicular tumors of interstitial cell (IC) origin in rats which can be prevented by zinc (Zn). Zn-induced synthesis of metallothionein (MT), a metal-binding protein with a high affinity for Cd, is thought to account for tolerance to Cd in most tissues by sequenstration of Cd. However, the mechanism of Zn inhibition of Cd-induced carcinogenesis in the testes is unknown. Our studies with ICs obtained by collagenase dispersion of rat testes, indicate the levels of the Cd-binding protein in ICs are unaltered by Zn. This testicular protein also was found to differe from MT in amino acid content and to have a lower affinity for Cd. Thus, MT does not seem to be involved in protection of ICs against Cd carcinogenesis. Altered Cd toxicokinetics as a possible explantation for Zn-induced tolerance was therefore explored. Cd uptake into isolated ICs had passive diffusion and nonpassive (carrier mediated or active transport or both) components. The nonpassive component of Cd accumulation was markedly reduced by addition of Zn in vitro, indicative of competition for uptake at the cellular level. These results indicate that toxicokinetic alterations leading to reduced Cd accumulation may play an important role in Zn induction of tolerance to Cd carcinogenesis in the testes. Paper presented at the 38th Annual Meeting of the Tissue Culture Association in Arlington, Virginia, in May 1987. The session was chaired by Dr. Carlton H. Nadolney, member of the TCA Committee on Toxicity, Carcinogenesis and Mutagenesis Evaluation.     

Evaluation of chromosomal aberrations in lymphocytes and micronuclei in lymphocytes, oral mucosa and hair root cells of patients under antiblastic therapy

In 7 patients undergoing antiblastic chemotherapy for the first time, the structural chromosomal aberration (CA) test in peripheral lymphocytes was compared with the micronucleus (Mn) test in lymphocytes, in oral cavity cells and in hair root cells of the scalp. The last test is being proposed for the first time. The CA and Mn frequencies induced by chemotherapy were compared with the baseline (pretreatment) frequencies of the patients and with confidence limits calculated in 4 control groups studied for CA, Mn in lymphocytes, Mn in oral cavity cells and Mn in hair root cells, respectively. The studied chemotherapies induced a clear cytogenetic effect in at least 2 of the tests studied with the exception of interferon-alpha 2b (patient 6) and interferon + low doses of cis-platinum (patient 2) which did not appear to cause evident chromosomal damage. The response to chemotherapy is generally characterized by an increase in Ca and Mn, reaching a peak value and then decreasing in the following weeks. The CA test proves to be the most sensitive despite the fact that CA were analyzed in an average of 100 cells per sample against the 500-3000 cells analyzed for Mn. The efficiency of Mn to detect CA is in the following order: Mn in lymphocytes greater than Mn in buccal cells greater than Mn in hair root cells. The last test appears to be very promising but, used following the current method, does not appear suitable to monitor acute exposure.     

Levels of selenium, zinc, copper, and antioxidant enzyme activity in patients with leukemia

Essential elements, mainly selenium and zinc, were involved in protection against oxidative stress in cells. Oxidation could lead to the formation of free radicals that have been implicated in the pathogenesis of many diseases, including leukemia. Leukemia is a neoplastic disease that is susceptible to antioxidant enzyme and essential elements alterations. This study was undertaken to examine the levels of essential elements, antioxidant enzymes activities, and their relationships with different types of leukemia. Serum selenium, zinc, and copper concentrations, red blood cell glutathione peroxidase (GPx) activities, plasma Cu−Zn superoxide dismutase (Cu−Zn SOD) activities and lipid peroxidation (LPO) levels were determined in 49 patients with different types of leukemia before initial treatment. Serum selenium and zinc concentrations were lower in leukemia patients than those of controls (p<0.01). Serum copper concentration was higher in leukemia patients than that of controls (p<0.01). The activities GPx and Cu−Zn SOD were significantly increased in leukemia patients, especially with acute leukemia (AL), acute lymphoid leukemia (ALL), and acute nonlymphoid leukemia (ANLL) (p<0.05), whereas no difference was found between those of chronic myelogeneous leukemia and the controls. The levels of LPO were normal as controls. Serum selenium concentration was not correlated with GPx, and serum levels of zinc and copper were not related to Cu−Zn SOD. Serum zinc levels had a negative correlation with the absolute peripheral blast cells, whereas serum copper had a positive correlation with the absolute peripheral blast cells. Increased GPx and Cu−Zn SOD activities and normal levels of LPO, which were a protective responses, were an indicator of mild oxidative stress; it mights indicate that the essentials elements alterations in leukemia patients were mostly dependent on tumor activity. Changes of their levels demonstrated that there are low selenium, zinc, and high copper status in leukemia patients. The decrease of plasma zinc and increase of the Cu/Zn ratio could be the index that showed an unfavorable prognosis of acute leukemia.