首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 406 毫秒
1.
Transport characteristics of essential trace elements as zinc, copper, selenium and iron have been studied in maternal–fetal direction in normal pregnancies, using in vitro perfusion of human placental lobules. Solutions of trace elements corresponding to twice the physiological concentrations were injected (100 l bolus) into the maternal arterial perfusate. Serial perfusate samples were collected every 30 sec from venous outflows for a study period of 5 min. Concentrations of these trace elements and their transport kinetics were determined. Transport fractions (TF) of zinc, copper, selenium and iron averaged 0.21, 0.49, 0.55 and 0.10% of maternal load respectively. Other parameters such as area under the curve, clearance, elimination constant, absorption and elimination rates showed some significant differences between the various elements. Copper and selenium appear to be transported passively in maternal–fetal direction, while for iron and zinc, role of active transport for transfer across the human placental membrane cannot be discounted. We speculate that alterations in copper: zinc TR50 (transport rate for 50% efflux) and TF ratios could serve as useful indicators for assessing placental transport status of these essential elements in complicated pregnancy states.  相似文献   

2.
The intestinal parasites are noted to be an important health problem in Turkey as similarly reported in the globe. The aim of this study was to investigate the changes in total content of essential elements, namely, zinc, iron, copper, cobalt, magnesium, and selenium, in children infected with intestinal parasites aged between 6 and 12 years inhabiting in Hatay Province, Turkey. These essential elements were measured in the children/patient who was positive for intestinal parasites, Giardia intestinalis and Enterobius vermicularis. Scores were obtained from the positive study group (SG), and their age matched the healthy children control group (CG). Serological levels of zinc, iron, copper, cobalt, magnesium, and selenium were analyzed by Varian Liberty Series II inductively coupled plasma atomic emission spectrometer (ICP-AES). The mean magnesium concentrations were found to be statistically different at 95% confidence interval level between study groups. As a result of this study, selenium was found to be uncorrelated with all other elements examined; whereas, copper was observed to have statistically significant correlations with cobalt, magnesium, and zinc. In addition, cobalt-magnesium, cobalt-zinc, and magnesium-zinc metal pairs were found to have statistically significant correlations based on study findings.  相似文献   

3.
Effects of zinc, copper, and selenium on placental cadmium transport   总被引:1,自引:0,他引:1  
The objective of the present study was to evaluate the potential effects of zinc, copper, and selenium on placental cadmium transport. From November 2002 through January 2003, a total of 47 healthy pregnant women from Da-Ye City, Hubei Province in Central China participated in the study. Their age, parity, gestational age, pregnancy history, and lifestyle data were obtained by questionnaire interview. The placental, whole-blood, and cord blood levels of cadmium were determined by inductively coupled plasma mass spectrometer (ICP-MS), whole-blood zinc was measured by flame atomic absorption spectrometry (F-AAS), whole-blood copper by ICP-MS, and selenium was by atomic fluorescence spectrophotometry (AFS). The cord blood cadmium concentration (0.020-1.48 microg/L) was significantly lower than in maternal blood (0.80-25.20 microg/L, p<0.01). The placental cadmium concentration was from 0.082 to 3.97 microg/g dry weight. Multiple linear regression analysis indicated that lower levels of maternal blood copper were significantly associated with higher cadmium concentrations in cord blood. Placental cadmium in women with lower levels of maternal blood zinc was significantly higher than in those with normal zinc levels. The placental cadmium level in women with lower whole-blood selenium was significantly lower than in subjects with normal selenium levels. It was concluded that the essential elements copper, selenium, and zinc might significantly affect placental cadmium transport.  相似文献   

4.
In a supplementation study in which organic selenium asl-selenomethionine was administered in low doses during 1 yr, alterations in the concentrations of metal ions in the erythrocytes and the neutrophil granulocytes were observed. In the erythrocytes, altered concentrations of zinc were parallel with selenium. The concentrations of magnesium, calcium, manganese, copper, and sulfur were not significantly altered. However, altered concentrations of iron and zinc were observed in the neutrophils. The concentrations of magnesium, calcium, manganese, copper, and sulfur were not significantly altered. The accumulation of selenium in individual blood cells was different from that obtained with supplementation of inorganic selenium. When organic selenium was supplemented, the thrombocytes accumulated more selenium than the erythrocytes and the neutrophil granulocytes. The observations indicate that selenium interacts with metal ions at the cellular level when supplemented in low doses. The chemical form of selenium might be important in nutrition and therapy in view of the interaction and distribution pattern at the cellular level.  相似文献   

5.
Viral hepatic diseases, especially those induced by the hepatitis B virus, can progress into more serious pathological outcomes and eventually to hepatocellular carcinoma. A growing body of evidence indicates that many trace elements play important roles in a number of carcinogenic processes that proceed through various mechanisms. To examine the status of trace elements during the development of hepatic carcinoma, we determined the selenium, iron, copper, and zinc levels and copper-to-zinc ratios in the serum of patients at different stages of viral hepatic disease. We observed significant changes in the selenium, iron copper, and zinc levels in the serum of patients having hepatocellular carcinoma, relative to those of healthy controls (p<0.05). The mean serum copper level in patients with hepatocellular carcinoma was significantly higher than that of the control group. In contrast, the mean selenium, iron, and zinc levels in patients having hepatocellular carcinoma were significantly lower than those of the control group. In addition, the mean zinc level in the serum of patients with hepatic cirrhosis was significantly lower than that of the control group (p<0.05). Moreover, we found markedly elevated Cu: Zn ratios (p<0.05) in patients having hepatic cirrhosis or hepatocellular carcinoma. Our findings imply that the levels of some trace elements, such as selenium, iron, copper, and zinc, and Cu:Zn ratios, might serve as biomarkers for the increased severity of viral hepatic damage.  相似文献   

6.
Cultures ofStreptomyces tendae andPenicillium expansum grown on Actinomyces and Czapek's media, respectively, were exposed to 5 mg L–1 of manganese, magnesium, iron, cobalt, nickel, copper and zinc, supplied as sulfate salts. Only copper markedly increased geosmin (1, 10-dimethyl-9-decalol), biomass, and spore production. inductively coupled plasma-atomic emission spectrometric analysis ofS. tendae andP. expansum cells did not indicate an accumulation of copper. Both 1 and 5 mg L–1 copper, as copper sulfate, increased total geosmin production in cultures ofS. tendae on several media, but decreased production on others, suggesting that substrate composition affects responses to copper.  相似文献   

7.
BackgroundMetabolic disorders of glucose and lipid were associated with some mineral elements, and data were warranted from various contexts to make the association more explicit.ObjectiveTo investigate the relationships between the serum concentrations of six mineral elements (calcium, cobalt, copper, iron, magnesium, and selenium) and the risk of hyperglycemia and dyslipidemia in adults.MethodsThe basic information and the over-night fasting serum samples of adults were randomly collected at a health examination center. The serum concentrations of glucose and lipids were measured with an automatic biochemical analyzer, and the mineral elements were measured with an inductively coupled plasma mass spectrometer. Data were analyzed between the hyperglycemia group (HGg) and the normal glucose group (NGg) as well as between the dyslipidemia group (DLg) and the normal lipid group (NLg).ResultsA total of 1466 adults aged 22–81 years (male/female = 1.8) were included, 110 in the HGg and 1356 in the NGg, or 873 in the DLg and 593 in the NLg. The serum element concentration medians [P50 (P25–P75)] significantly different between the HGg and the NGg were 0.83 (0.75–0.94) vs. 0.76 (0.68–0.87) mg/L for copper and 100 (90–110) vs. 94 (87–103) μg/L for selenium (P < 0.001), while those between the DLg and the NLg were 99 (92–110) vs. 97 (90–106) mg/L for calcium, 0.78 (0.69–0.88) vs. 0.75 (0.66–0.85) mg/L for copper, 1.7 (1.4–2.0) vs. 1.6 (1.3–2.0) mg/L for iron, 24 (22–28) vs. 23 (22–27) mg/L for magnesium, and 97 (89–106) vs. 92 (84–100) μg/L for selenium (P < 0.05). When the copper and selenium between the HGg and the NGg were analyzed by logistic regression with age, gender, body mass index, and mineral elements adjusted, only the highest quartile of selenium concentration had association with the increased risk of hyperglycemia [quartile (Q) 4 against Q1: OR = 2.9, 95 % CI = 1.5–5.5, P < 0.001). When the five differed mineral elements between the DLg and the NLg were similarly analyzed, only iron and selenium had associations with the increased risk of dyslipidemia (e.g., Q4 against Q1: OR = 1.4, 95 % CI = 1.1–2.0 for iron and OR = 2.9, 95 % CI = 2.1–4.0 for selenium, P < 0.05).ConclusionIn contrast to those of calcium, cobalt, copper, iron, and magnesium, the higher serum concentration of selenium increased the risk of both hyperglycemia and dyslipidemia in the study population of adult Chinese.  相似文献   

8.
Transport proteins of microorganisms may either belong to the ATP-binding cassette (ABC) superfamily or to the major facilitator (MFS)-superfamily. MFS transporters are single-polypeptide membrane transporters that transport small molecules via uniport, symport or antiport mechanisms in response to a chemiosmotic gradient. Although Saccharomyces cerevisiae is a non-siderophore producer, various bacterial and fungal siderophores can be utilized as an iron source. From yeast genome sequencing data six genes of the unknown major facilitator (UMF) family were known of which YEL065w Sce was recently identified as a transporter for the bacterial siderophore ferrioxamine B (Sit1p). The present investigation shows that another UMF gene, YHL047c Sce, encodes a transporter for the fungal siderophore triacetylfusarinine C. The gene YHL047c Sce (designated TAF1) was disrupted using the kanMX disruption module in a fet3 background (strain DEY 1394 fet3), possessing a defect in the high affinity ferrous iron transport. Growth promotion assays and transport experiments with 55Fe-labelled triacetylfusarinine C showed a complete loss of iron utilization and uptake in the disrupted strain, indicating that TAF1 is the gene for the fungal triacetylfusarinine transport in Saccharomyces cerevisiae and possibly in other siderophore producing fungi.  相似文献   

9.
Transport of nickel ions was studied in Alcaligenes eutrophus. Two transport systems for nickel ions exist to satisfy the nickel demand for the lithotrophic hydrogen metabolism. A major nickel transport activity exhibited an apparent affinity constant (K m) of 17 M nickel chloride. This activity was competitively inhibited by Mg2+, Mn2+, Zn2+, and Co2+. A minor nickel transport activity was determined in the presence of high (0.8 mM) magnesium. This activity was not inhibited by Zn2+ or Mn2+; its K m was determined to be 0.34 M nickel chloride. These kinetics suggested a second transport system in A. eutrophus. The membrane potential of A. eutrophus was decreased upon the addition of ammonium ions leading to a decreased nickel transport. This inhibition could be reversed by fructose or by hydrogen indicating an energy dependent nickel transport. Protonophores inhibited the nickel transport. However, inhibitors of ATP synthase like dicyclohexylcabodimide or venturicidin had little or no effect on nickel transport. These data indicated that the transport was coupled to the proton motive force.  相似文献   

10.
X-ray radiation is detrimental to human cells and may lead to development of life-threatening diseases. Cigarette paper and cigarette smoke contain toxic elements, whereas vitamins C and E (VCE) may have regulator effects on the elements. We investigated effects of VCE administration on X-ray-induced element changes in blood of smoker and nonsmoker X-ray technicians. Twenty technicians and 30 healthy age-matched control subjects were used in the study. Ten of the X-ray technicians and 15 of the control were smokers. Blood serum samples were taken from the control. Oral vitamins C (500 mg) and E (150 mg) were supplemented daily to the smoker and nonsmoker X-ray technicians for 5 weeks. Serum samples were taken from the X-ray technicians before and after 5 weeks. Copper, zinc, selenium, aluminum, iron, magnesium, and calcium levels were investigated in control and X-ray technicians, both smokers and nonsmokers. Copper, zinc, and selenium levels were lower in the total X-ray group and smoker X-ray group than in control and nonsmoker X-ray group, although iron, magnesium, and calcium levels were higher in X-ray group than in control. The copper, zinc, selenium, and aluminum levels were higher in the VCE treatment group than those in X-ray group, although magnesium and calcium levels were decreased by the treatment. The serum zinc, copper, selenium, and magnesium levels were lower in smoker control group when compared to nonsmoker control group. The serum zinc levels were lower in smoker X-ray group than nonsmoker X-ray group, although iron level was higher in smoker X-ray group than in nonsmoker X-ray group. VCE prevents the smoke and X-ray-induced selenium, zinc, magnesium, and copper decrease to strengthen the antioxidant trace element levels in the serum of the technicians.  相似文献   

11.
The combined effects of vitamin E and selenium were studied in native Anatolian horses subject to strenuous exercise. The concentrations of copper, zinc, iron, calcium, potassium, and magnesium were determined in serum by atomic absorption spectrometry in two study groups (n = 25 each), one of which served as untreated controls. After exercising the horses by running 1,500 m in about 7 min, only the copper level and the copper/zinc ratio significantly increased (p < 0.05), but the concentrations of calcium, potassium, iron, and magnesium remained unchanged. In horses treated with vitamin E and selenium, the calcium and potassium levels decreased to levels lower than those of untreated controls before and after exercise. The iron levels were not changed by exercise or treatment alone but increased when the horses had been supplemented and exercised. The copper level and the copper/zinc ration increased as a result of exercise in both treated and untreated horses. These changes suggest that supplementation with vitamin E and selenium had an important effect on the serum concentrations of calcium, potassium, copper, iron, and the copper/zinc ratio.  相似文献   

12.
Summary Cells of the fungusNeurospora crassa were grown under iron-deficient and iron-sufficient conditions and their plasma membrane proteins were compared. Three strains were studied:N. crassa 74A (wild type), a siderophore-free mutantN. crassa (arg-5 ota aga) as well as a slime variant ofN. crassa which lacks a cell wall. Plasma membranes were purified, solubilized and analyzed by one-dimensional SDS/polyacrylamide gel electrophoresis yielding approximately 50 distinct protein bands with molecular masses in the range 14–160 kDa. Iron-sufficient and iron-deficient growth resulted in nearly identical plasma membrane protein profiles in all strains. Although minor alterations in the proportion of certain proteins could be detected, significant overproduction of certain membrane proteins during iron limitation could not be observed. Transport of55 Fe-labeled siderophores seems to be correlated to the degree of iron limitation. For example, transport rates were enhanced five-fold after 16 h of growth in iron-deficient medium compared to growth in iron-sufficient medium. Extraction and HPLC measurement of siderophores from conidiospores yielded approximately 10–15 mol/spore, indicating that germination tubes and young cells used for transport measurements are not iron-deficient. It is suggested that the putative transport systems for siderophores in fungal plasma membranes are constitutively expressed and enhanced uptake of siderophores during iron limitation is rather the result of cellular transport regulation mechanisms.  相似文献   

13.
Summary Cisplatin (CDDP)-sensitive and -resistant human ovarian cells were studied in vitro with the objective of enhancing CDDP cytotoxicity by the addition of a metal and the chelate ethylenediaminetetraacetic acid (EDTA), to the CDDP. Chelateable elements, such as bismuth, calcium, cadmium, copper, iron, magnesium, selenium, vanadium, and zinc, when added to CDDP and in the presence of EDTA increased the cytotoxicity of the CDDP as compared to CDDP treatment alone.  相似文献   

14.
Adolescence is marked by intensive growth and development. When pregnancy occurs during this period of the mother’s growth, there is an increase in her nutritional needs. The aim of this study was to determine the levels of calcium, iron, copper, and zinc in maternal plasma, the placenta, and in the cord plasma of pregnant teenagers and adults. A total of 80 sets of maternal plasma, placentas, and cord plasma (40 from teenagers and 40 from adults) were analyzed using synchrotron radiation total reflection X-ray fluorescence. The levels of calcium, copper, and zinc in the maternal and cord plasma from teenagers were not significantly different than those from adults. Iron levels in the teenagers maternal and cord plasma were higher than in the adults. All of the minerals analyzed were present at higher levels in the placentas from adults than those from teenagers. However, the low quantities of placental calcium, iron, copper, and zinc in the teenagers do not compromise the levels of these minerals in the cord plasma. Future research regarding the placental transport of these minerals is recommended to investigate the efficiency of mechanisms of transfer of these minerals in pregnant teenagers.  相似文献   

15.
Plasma essential trace elements, selenium, copper, zinc, and iron concentrations and the levels of immunoregulatory cytokines, interleukin-1β (IL-1β), interleukin-2 receptor (IL-2r), IL-6, IL-8, and tumor necrosis factor-α (TNF-α) were evaluated in patients with cutaneous leishmaniasis (CL) to investigate a possible role of these cytokines on selenium, zinc, copper, and iron homeostasis in CL patients. Plasma albumin levels were measured as an index of nutritional status. Plasma selenium, zinc, and iron concentrations, and IL-2r levels were significantly lower, and copper concentrations and IL-1β, IL-8, IL-6 and TNF-α levels were significantly higher in patients with CL than those of healthy controls. There was no significant difference in plasma albumin levels between two groups. There were positive important correlations between plasma selenium and IL-2r, copper and IL-6, and copper and IL-1β, and negative correlations between selenium and IL-8, iron and TNF-α, and zinc and IL-1β contents in patients with CL. Our results showed that plasma trace element contents change in patients with CL. These changes may not be a result of a specific deficiency from dietary inadequacies or imbalances, but, probably, a result of a part of the defense strategies of an organism that is regulated by immunoregulatory cytokines.  相似文献   

16.
The levels of seven trace elements such as copper, iron, zinc, selenium, cadmium, chromium, and nickel were determined by graphite furnace-atomic absorption spectrometry in the cervical mucus of 45 women residing in Taiwan, Republic of China. These women were in good health and had no precancerous or cancerous lesions on their cervix. The women were separated into four age groups to establish if there was a relationship between the age of the subjects and the values of these elements in the cervical mucus. By one-way analysis of variance, significant differences in the selenium and nickel concentrations were found among the four age groups (p<0.05). The mean concentration of selenium in each age group was significantly higher for the older women. A significant correlation between age and selenium concentration was found by linear regression (r=0.23, p=0.00048). No significant differences among the concentrations of copper, iron, zinc, cadmium, and chromium were found among these four age groups (p>0.05). The results presented in this work may be considered as baseline values for these elements in the cervical mucus of healthy Taiwanese women for use as reference in studies on cervical diseases and tissue damage.  相似文献   

17.
A method of bilateral perfusion of the isolated human placenta was used to study the urea transport from the fetal placental stream into the maternal one, and of amino acid transport in the opposite direction. Experiments demonstrated that the method provided a sufficiently full perfusion of the intervillous space and offered possibilities for studying the placental transport. With equal amino nitrogen concentration in both circulations, its content in the fetal stream increased during the experiment. This elevation was more expressed when amino acid was added to the maternal circulation. The idea of amino acid "secretion" by the trophoblast cell elements into the fetal circulation was confirmed by the above experiments.  相似文献   

18.
Pregnant women in developing countries are vulnerable to multiple micronutrient deficiencies. Studies assessing serum levels of the micronutrients and magnitude of their deficiencies are very scarce in African subjects. This study was aimed at determining serum levels of micronutrients in 375 pregnant (42 HIV seropositive) and 76 non-pregnant women (20 HIV seropositive) who visited the University of Gondar Hospital, Gondar, Ethiopia. Serum concentrations of zinc,\ copper, selenium, calcium, and magnesium were determined using an inductively coupled plasma mass spectrometer. Irrespective of HIV serostatus, pregnant women had significantly higher serum concentrations of copper and copper/zinc ratio and significantly lower magnesium compared to those in non-pregnant women (P < 0.05). Except for selenium, which was significantly lower in HIV-seropositive pregnant women (P < 0.05), the mean serum concentrations of zinc, copper, calcium, and magnesium were not significantly different between pregnant women by HIV serostatus. The prevalence of deficiency in zinc, magnesium, selenium, and calcium in the pregnant women, irrespective of their HIV serostatus, was 66.7%, 25.6%, 21.9%, and 9.3%, respectively. The magnitude of deficiency in zinc, magnesium, and selenium was significantly higher in HIV seropositive pregnant women (76.2%, 52.4%, and 45.2%) than that in HIV-seronegative pregnant women (65.5%, 22.2%, and 18.9%) and in HIV-seronegative non-pregnant women (42.9%, 8.1%, and 30.4%; P < 0.05). Deficiency in one, two, three, or four mineral elements was observed in 44.8%, 14.4%, 9.9%, and 5.1% of the pregnant women, respectively. Only 25.9% of the pregnant women and 44.7% of the non-pregnant women were not deficient in any of the micronutrients. The high prevalence of micronutrient deficiencies in pregnant and non-pregnant women in Gondar, Ethiopia warrants the need for strategies on prevention and control of the deficiencies.  相似文献   

19.
The divalent metal ion transporter DMT1 is localized in the brush border membrane (BBM) of the upper small intestine and has been shown to be able to transport Mn2+, Fe2+, Co2+, Ni2+, and Cu2+. Belgrade rats have a glycine-to-arginine (G185R) mutation in DMT1, which affects its function. We investigated copper transport with BBM vesicles of Belgrade rats loaded with calcein, which exhibits fluorescence quenching by various metal ions. Transport of copper was disrupted in unenergized BBM vesicle of b/b Belgrade rats, as had been described for iron transport, while +/b vesicles exhibited normal transport by DMT1. When either b/b or +/b vesicles were loaded with ATP and magnesium, similar high-affinity accumulation of copper was observed in both types of vesicles. Thus, brush border membranes possess an ATP-driven, high-affinity copper transport system which could serve as the primary route for copper uptake by the intestine.  相似文献   

20.
A direct method for determination of Fe, Cu, Zn, Mg and Se in erythrocytes was developed. The aim of the present study was to establish a method for examining perioperative levels of the above mentioned elements simultaneously in erythrocytes and plasma by atomic absorption spectrophotometry in 11 patients undergoing neurosurgery for acute spinal nerve compressions because of intervertebral disk prolapses. Reference values for erythrocytes were 11.49 +/- 3.48 mmol/mmol Hb; 0.82 +/- 0.087 mmol/mmol Hb; 9.01 +/- 2.20 mmol/mmol Hb; 0.104 +/- 0.032 mmol/mmol Hb; 0.07 +/- 0.050 mmol/mmol Hb for iron, copper, zinc, magnesium, and selenium, respectively. Postoperative erythrocyte concentrations did not differ significantly compared to those obtained preoperatively and remained within the reference ranges perioperatively. For plasma the following reference values were used: 19.0 +/- 8.0 mmol/l (Fe); 20.1 +/- 8.2 mmol/l (Cu); 15.4 +/- 4.6 mmol/l (Zn); 0.9 +/- 0.15 mmol/l (Mg); 1.02 +/- 0.3 mmol/l (Se). There was a significant decrease in the concentration of copper in plasma (13.41 +/- 3.46 mmol/l, p < 0.1) and zinc (10.73 +/- 2.73 mmol/l, p < 0.1) immediately postoperative, iron (10.56 +/- 3.91 mmol/l, p < 0.1) and zinc on day 1 (11.28 +/- 1.88 mmol/l, p < 0.10), and a significant postoperative increase of copper on day 5 (18.81 +/- 3.97 mmol/l, p < 0.1), postoperatively. The mean plasma concentrations of iron, copper, zinc magnesium and selenium remained within the reference ranges during the entire period.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号