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1

The chemistry of ferrous bis-glycinate chelate.  

PubMed

In order to produce a ferrous chelate four criteria must be met: 1) the ligand must contain two functional groups which are capable of entering into covalent and coordinate covalent bonds; 2) a ring structure with the ferrous ion being the closing member of the ring must be created; 3) the chelate must be sterically possible; and 4) the chelation reaction must be energetically possible. In addition to the above, a totally nutritionally functional ferrous chelate must meet three further criteria: 1) it must have low molecular weight; 2) its stability constant must be nutritionally functional; and 3) the ligand must be metabolizable by the body. When ferrous iron is reacted with glycine and forms a bis-glycinate chelate, it meets all of the requirements of being both a chelate and being a totally nutritionally functional chelate. PMID:11688084

Ashmead, S D

2001-03-01

2

Milk Inhibits and Ascorbic Acid Favors Ferrous Bis-Glycine Chelate Bioavailability in Humans1,2  

Microsoft Academic Search

The chemical properties of ferrous bis-glycine chelate allow for its use as a fortificant in fluid, high fat vehicles. This chemical form may also protect iron from the inhibitory or enhancing effects of the diet on iron absorption. Alternatively, iron bis-glycine chelate may be absorbed by a mechanism independent of an individual's iron stores. To test these hypotheses, the bioavailability

Manuel Olivares; Fernando Pizarro; Oscar Pineda; Eva Hertrampf; Tomas Walter

3

Effectiveness of treatment of iron-deficiency anemia in infants and young children with ferrous bis-glycinate chelate.  

PubMed

Forty infants, 6 to 36 mo old, with iron-deficiency anemia (hemoglobin < 11 g/dL) were matched and assigned to two groups. One group received FeS0(4) and the other received ferrous bis-glycinate chelate at a dose of 5 mg of Fe daily per kilogram of body weight for 28 d. Both groups had significant hemoglobin increases (P < 0.001), but only the group treated with ferrous bis-glycinate chelate had significant increases (P < 0.005) in plasma ferritin. Apparent iron bioavailabilities were calculated at 26.7% for FeS0(4) and 90.9% for ferrous bis-glycinate chelate. Regression analysis indicated that absorption of both sources of iron were similarly regulated by the body according to changes in hemoglobin. We concluded that ferrous bis-glycinate chelate is the iron of choice for the treatment of infants with iron-deficiency anemia because of its high bioavailability and good regulation. PMID:11377130

Pineda, O; Ashmead, H D

2001-05-01

4

Effectiveness of treatment of iron-deficiency anemia in infants and young children with ferrous bis-glycinate chelate  

Microsoft Academic Search

Forty infants, 6 to 36 mo old, with iron-deficiency anemia (hemoglobin < 11 g\\/dL) were matched and assigned to two groups. One group received FeS04 and the other received ferrous bis-glycinate chelate at a dose of 5 mg of Fe daily per kilogram of body weight for 28 d. Both groups had significant hemoglobin increases (P < 0.001), but only

Oscar Pineda; H. DeWayne Ashmead

2001-01-01

5

Bioavailability of iron bis-glycinate chelate in water.  

PubMed

Iron amino acid chelate is being increasingly considered in programs for iron fortification of foods. The bioavailability of iron bis-glycinate chelate given in water was studied using a double-isotopic method in a group of 14 women. Iron absorption from aqueous solutions of 15 mg/L of elemental iron as either iron bis-glycine chelate or ferrous ascorbate was not significantly different (34.6% and 29.9% respectively). Standardized iron absorption of the iron bis-glycinate was 46.3% (standardized to 40% absorption of the reference dose). There was a significant correlations between (ln) iron absorption of iron bis-glycinate chelate with (ln) serum ferritin (r = -0.60, p < 0.03) and with (ln) iron absorption from ferrous ascorbate (r = 0.71, p < 0.006), suggesting that iron bis-glycinate chelate absorption is indeed regulated by the iron stores of the body. PMID:11688077

Olivares, M; Pizarro, F

2001-03-01

6

Effect of supplementation with ferrous sulfate or iron bis-glycinate chelate on ferritin concentration in Mexican schoolchildren: a randomized controlled trial  

PubMed Central

Background Iron deficiency is one of the most common nutritional deficiencies worldwide. It is more prevalent when iron requirements are increased during pregnancy and during growth spurts of infancy and adolescence. The last stage in the process of iron depletion is characterized by a decrease in hemoglobin concentration, resulting in iron deficiency anemia. Iron deficiency, even before it is clinically identified as anemia, compromises the immune response, physical capacity for work, and intellectual functions such as attention level. Therefore, interventions addressing iron deficiency should be based on prevention rather than on treatment of anemia. The aim of this study was to compare short- and medium-term effects on ferritin concentration of daily supplementation with ferrous sulfate or iron bis-glycinate chelate in schoolchildren with iron deficiency but without anemia. Methods Two hundred schoolchildren from public boarding schools in Mexico City who had low iron stores as assessed by serum ferritin concentration but without anemia were randomly assigned to a daily supplement of 30 mg/day of elemental iron as ferrous sulfate or iron bis-glycinate chelate for 12 weeks. Iron status was evaluated at baseline, one week post-supplementation (short term), and 6 months (medium term) after supplementation. Results Ferritin concentration increased significantly between baseline and post-supplementation as well as between baseline and 6 months after supplementation. One week post-supplementation no difference was found in ferritin concentration between iron compounds, but 6 months after supplementation ferritin concentration was higher in the group that received bis-glycinate chelate iron. However, there is no difference in the odds for low iron storage between 6 months after supplementation versus the odds after supplementation; nor were these odds different by type of supplement. Hemoglobin concentration did not change significantly in either group after supplementation. Conclusions Supplementing with 30 mg/d of elementary iron, either as ferrous sulfate or iron bis-glycinate chelate for 90 days, showed positive effects on increasing ferritin concentration in schoolchildren with low iron stores, and this effect persisted 6 months after supplementation. PMID:25023784

2014-01-01

7

Relative effectiveness of iron bis-glycinate chelate (Ferrochel) and ferrous sulfate in the control of iron deficiency in pregnant women.  

PubMed

The relative effectiveness of daily supplementation of iron deficiency during pregnancy using 15 mg/day of iron from iron-bis-glycinate chelate (71 pregnant women), or 40 mg iron from ferrous sulfate (74 pregnant women) was evaluated by measuring hemoglobin, transferrin saturation and serum ferritin, at the beginning of the study (< 20 weeks of pregnancy) and at 20-30 weeks and 30-40 weeks thereafter. Ingestion for 13 weeks or more was considered adequate. Seventy three percent of the Ferrochel consuming group and 35% of the ferrous sulfate consuming group were considered to have taken the treatment adequately. The decrease in levels of all the measured parameters was significantly less pronounced in the group that consumed Ferrochel in spite of the lower treatment dose. Iron depletion was found in 30.8% of the women treated with Ferrochel and in 54.5% of the women than consumed ferrous sulfate. Of the factors responsible for non compliance taste was reported in 29.8% of the ferrous sulfate consumers and none in the groups that consumed Ferrochel. It is concluded that daily supplementation with Ferrochel was significantly more effective, in spite of the lower dose, than supplementation with ferrous sulfate. PMID:11688081

Szarfarc, S C; de Cassana, L M; Fujimori, E; Guerra-Shinohara, E M; de Oliveira, I M

2001-03-01

8

The effect of change in pH on the solubility of iron bis-glycinate chelate and other iron compounds.  

PubMed

The effect of a pH change from 2 to 6 was tested on the solubility of ferrous sulfate, ferrous fumarate, iron bis-glycine chelate (Ferrochel) and sodium-iron ethylenediaminetetraacetic acid (NaFeEDTA). It was found that at pH 2 ferrous sulfate, Ferrochel and NaFeEDTA were completely soluble and only 75% of iron from ferrous fumarate was soluble. When pH was raised to 6, iron from amino acid chelate and NaFeEDTA remained completely soluble while solubility from ferrous sulfate and ferrous fumarate decreased 64 and 74%, respectively compared to the amount of iron initially soluble at pH 2. These results suggest that iron solubility from iron bis-glycine chelate and NaFeEDTA is not affected by pH changes within the ranges tested, probably because iron remained associated to the respective compounds. PMID:11688079

García-Casal, M N; Layrisse, M

2001-03-01

9

Iron amino acid chelates.  

PubMed

Iron amino acid chelates, such as iron glycinate chelates, have been developed to be used as food fortificants and therapeutic agents in the prevention and treatment of iron deficiency anemia. Ferrous bis-glycine chelate (FeBC), ferric tris-glycine chelate, ferric glycinate, and ferrous bis-glycinate hydrochloride are available commercially. FeBC is the most studied and used form. Iron absorption from FeBC is affected by enhancers and inhibitors of iron absorption, but to a lesser extent than ferrous sulfate. Its absorption is regulated by iron stores. FeBC is better absorbed from milk, wheat, whole maize flour, and precooked corn flour than is ferrous sulfate. Supplementation trials have demonstrated that FeBC is efficacious in treating iron deficiency anemia. Consumption of FeBC-fortified liquid milk, dairy products, wheat rolls, and multi-nutrient beverages is associated with an improvement of iron status. The main limitations to the widespread use of FeBC in national fortification programs are the cost and the potential for promoting organoleptic changes in some food matrices. Additional research is required to establish the bioavailability of FeBC in different food matrices. Other amino acid chelates should also be evaluated. Finally there is an urgent need for more rigorous efficacy trials designed to define the relative merits of amino acid chelates when compared with bioavailable iron salts such as ferrous sulfate and ferrous fumarate and to determine appropriate fortification levels PMID:15743019

Hertrampf, Eva; Olivares, Manuel

2004-11-01

10

The use of sweet rolls fortified with iron bis-glycinate chelate in the prevention of iron deficiency anemia in preschool children.  

PubMed

The effectiveness of bread fortified with iron bis-glycinate chelate for the control of iron deficiency and iron deficiency anemia was evaluated in 89 preschool children from families of low socioeconomic level attending 2 day nurseries of the Sao Paulo City Council. During the intervention's time of 6 months the children received besides their usual center's diet, a daily supplement of two sweet rolls fortified with 2 mg each of iron from the chelate for a total daily iron intake of 4 mg. After six months of intervention there was a significant decrease in the prevalence of iron deficiency anemia from 62 to 22%. There was a mean hemoglobin improvement of 1.1 g/dL, and in children with initial hemoglobin levels < 11 g/dL the mean increase in hemoglobin was 1.42 g/dL. The total mean plasma ferritin values increased from 11.34 to 20.2 micrograms/L, and in those children originally iron depleted the ferritin values normalized. A significant increase in the "z" score for weight/height was also observed. We concluded that the use of sweet rolls fortified with 2 mg of iron from the bis-glycinate chelate is highly effective for the control of iron deficiency and iron deficiency anemia in young children. PMID:11688082

Giorgini, E; Fisberg, M; De Paula, R A; Ferreira, A M; Valle, J; Braga, J A

2001-03-01

11

Effect of iron chelates on oil–water interface, stabilized by milk proteins: The role of phosphate groups and pH. Prediction of iron transfer from aqueous phase toward fat globule surface by changes of interfacial properties  

Microsoft Academic Search

Iron incorporated into food systems induces oxidation and precipitation. The consequences are reduced bioavailability and a functional modification of other food components such as proteins. The iron-chelates such as ferrous bisglycinate represent a possibility to avoid side effects, since the iron is protected. The aim of this study is to investigate the effects of iron-chelates compounds on the properties of

Tatiana Guzun-Cojocaru; Philippe Cayot; Camille Loupiac; Eliane Cases

2010-01-01

12

Comparison of ferrous sulfate and ferrous glycinate chelate for the treatment of iron deficiency anemia in gastrectomized patients  

Microsoft Academic Search

ObjectivesPostgastrectomy iron deficiency anemia has a variable prevalence and occurs in 20–50% of patients. Food fortification reports examining ferrous glycinate chelate have shown that it can be 2.5–3.4 times more bioavailable than ferrous sulfate, with minimal gastrointestinal symptoms. The present study was designed as a controlled experimental study including 18 gastrectomized patients with iron deficiency anemia to compare the effects

Érika C. Mayumi Mimura; José Wander Breganó; Jane Bandeira Dichi; Emerson Pereira Gregório; Isaias Dichi

2008-01-01

13

Molecular characterization of whey protein hydrolysate fractions with ferrous chelating and enhanced iron solubility capabilities.  

PubMed

The ferrous (Fe(2+)) chelating capabilities of WPI hydrolysate fractions produced via cascade membrane filtration were investigated, specifically 1 kDa permeate (P) and 30 kDa retentate (R) fractions. The 1 kDa-P possessed a Fe(2+) chelating capability at 1 g L(-1) equivalent to 84.4 ?M EDTA (for 30 kDa-R the value was 8.7 ?M EDTA). Fourier transformed infrared (FTIR) spectroscopy was utilized to investigate the structural characteristics of hydrolysates and molecular interactions with Fe(2+). Solid-phase extraction was employed to enrich for chelating activity; the most potent chelating fraction was enriched in histidine and lysine. The solubility of ferrous sulfate solutions (10 mM) over a range of pH values was significantly (P < 0.05) improved in dispersions of hydrolysate fraction solutions (10 g protein L(-1)). Total iron solubility was improved by 72% in the presence of the 1 kDa-P fraction following simulated gastrointestinal digestion (SGID) compared to control FeSO4·7H2O solutions. PMID:25716093

O'Loughlin, Ian B; Kelly, Phil M; Murray, Brian A; FitzGerald, Richard J; Brodkorb, Andre

2015-03-18

14

Preparation of ferrous chelate of hairtail (Trichiurus haumela) protein hydrolysate (Fe(II)-HPH) and its antibacterial activity  

NASA Astrophysics Data System (ADS)

The preparation of a ferrous chelate of hairtail (Trichiurus haumela) protein hydrolysate (Fe(II)-HPH) and its antibacterial activity were studied. The optimal conditions of hydrolysis by papain and ferrous chelation were obtained by single-factor experiments and orthogonal test, with the antibacterial activities as the index. In addition, the antibacterial activity of Fe(II)-HPH was evaluated using the Plackett-Burman design. The orthogonal test results showed that Fe(II)-HPH had an antibacterial activity of 98.3% under a temperature of 40 °C at pH 6.5 for an enzymolysis duration of eight hours in the presence of 20,000 U/g of enzyme. The Plackett-Burman design analysis showed that the three most significant factors (P < 0.05) influencing the antibacterial activity of Fe(II)-HPH were pH, the concentration (mg/mL), and presence of magnesium sulfate.

Lin, Huimin; Zhang, Bin; Yu, Tian; Deng, Shanggui

15

Combined NO/sub x//SO/sub 2/ removal from flue gas using ferrous chelates of SH-containing amino acids and alkali  

SciTech Connect

We report herein the use of ferrous chelates of SH-containing amino acids including cysteine, penicillamine, N-acetylcysteine, and N-acetylpenicillamine in neutral or alkaline solutions for the combined removal of NO and SO/sub 2/ in wet flue gas clean-up systems. These SH-containing amino acids not only can stabilize ferrous ions in alkaline solutions to promote the absorption of NO, but are also capable of rapidly reducing ferric ions formed during the scrubbing process back to ferrous ions. The disulfide form of the above amino acids can be reduced by SO/sub 2/ and H/sub 2/S to regenerate the starting monomeric species. The chemistry relevant to the absorption of NO by the above ferrous chelates and the ligand regeneration process will be discussed.

Liu, D.K.; Chang, S.G.

1987-04-01

16

Combined NO/sub x//SO/sub 2/ removal from flue gas using ferrous chelates of SH-containing amino acids and alkali  

SciTech Connect

We report herein the use of ferrous chelates of SH-containing amino acids including cysteine, penicillamine, N-acetylcysteine, and N-acetylpenicillamine in neutral or alkaline solutions for the combined removal of NO and SO/sub 2/ in wet flue gas clean-up systems. These SH-containing amino acids not only can stabilize ferrous ions in alkaline solutions to promote the absorption of NO, but are also capable of rapidly reducing ferric ions formed during the scrubbing process back to ferrous ions. The disulfide from of the above amino acids can be reduced by SO/sub 2/ and H/sub 2/S to regenerate the starting monomeric species. The chemistry relevant to the absorption of NO by the above ferrous chelates and the ligand regeneration process will be discussed.

Liu, D.K.; Chang, S.G.

1987-01-01

17

Use of ferrous chelates of SH-containing amino acids and peptides for the removal of NO/sub x/ and SO/sub 2/ from flue gas  

SciTech Connect

The use of ferrous complexes of SH-containing amino acids and peptides for the removal of NO and SO/sub 2/ in wet flue gas clean-up systems is reported. The ferrous chelates investigated in the present study include those of cysteine, N-acetylcysteine, penicillamine, N-acetylpenicillamine, glutathine, and cysteinylglycine. Compared to conventional chelates such as EDTA, these thioamino acids/peptides not only can stabilize ferrous ion in alkaline solutions to promote the absorption of NO but are also capable of rapidly reducing any ferric ions formed during the scrubbing process back to ferrous ions so that continual absorption of NO can be achieved. In the case of ferrous cysteine and ferrous penicillamine, most of the absorbed NO is reduced to N/sub 2/. The disulfide form of several of the thioamino acids/peptides produced upon oxidation can be conveniently reduced by SO/sub 2/ and H/sub 2/S to regenerate the starting materials, thus making possible the recycling of the reagents.

Chang, S.G.; Littlejohn, D.; Liu, D.K.

1988-11-01

18

Persulfate oxidation for in situ remediation of TCE. II. Activated by chelated ferrous ion  

Microsoft Academic Search

In situ chemical oxidation (ISCO) is a technique used to remediate contaminated soil and groundwater systems. It has been postulated that sodium persulfate (Na2S2O8) can be activated by transition metal ions such as ferrous ion (Fe2+) to produce a powerful oxidant known as the sulfate free radical (SO4?) with a redox potential of 2.6 V, which can potentially destroy organic

Chenju Liang; Clifford J Bruell; Michael C Marley; Kenneth L Sperry

2004-01-01

19

FERROUS GLYCINATE (PROCESSED WITH CITRIC ACID) First draft prepared by  

Microsoft Academic Search

1. EXPLANATION The call for data for the sixty-first meeting referred to this substance as ferrous bisglycinate. The Committee decided that this name did not accurately describe the substance being evaluated and therefore agreed that it should be referred to as \\

Gary Williams

20

On the existence of “bis-glycine maleate”  

NASA Astrophysics Data System (ADS)

We argue that the crystal "bis-glycine maleate", reported by D. Balasubramanian et al., J. Cryst. Growth 312 (2010) 1855-1859, actually is glycinium hydrogen maleate previously reported by K. Rajagopal et al., Acta Crystallogr. E57 (2001) o751-o753.

Petrosyan, A. M.; Ghazaryan, V. V.; Fleck, M.

2012-11-01

21

Ferric chelate reduction by suspension culture cells and roots of soybean: A kinetic comparison  

Microsoft Academic Search

The abilities of suspension cultures and intact roots of soybean (Glycine max L. cv. Hawkeye) to reduce ferric chelate were compared. Ferric chelate was supplied as ferric hydroxyethylethylenediaminetriacetic acid (FeHEDTA) and reduction was measured spectrophotometrically using bathophenan-throlinedisulfonic acid (BPDS) as the ferrous scavenger. Ferric chelate reduction by cell suspension cultures showed typical saturation kinetics; however, no difference was observed between

J. D. Cornett; G. V. Johnson

1991-01-01

22

Structural, optical and dielectric studies of novel non-linear Bisglycine Lithium Nitrate piezoelectric single crystal  

NASA Astrophysics Data System (ADS)

The novel non-linear semiorganic Bisglycine Lithium Nitrate (BGLiN) single crystals were grown by slow evaporation technique. The structural analysis revealed that it belongs to non-centrosymmetric orthorhombic structure. The presence of various functional groups in the grown crystal was confirmed by FTIR and Raman analysis. Surface morphology of the grown crystal was studied by scanning electron microscopy. The optical studies show that crystal has good transmittance (more than 80%) in the entire visible region and a wide band gap (5.17 eV). The optical constants such as extinction coefficient (K), the reflectance (R) and refractive index (n) as a function of photon energy were calculated from the optical measurements. With the help of these optical constants the electric susceptibility (?c) and both the real (?r) and imaginary (?i) parts of the dielectric constants were also calculated which are required to develop optoelectronic devices. In photoluminescence studies, a broad emission band centered at 404 nm was found in addition to a small band at 352 nm. A broad transition (from 29 to 33 °C) was observed with low dielectric constant value. A high piezoelectric charge coefficient (d33) of 14 pC/N was measured at room temperature which implies its usefulness for various sensor applications. The second harmonic generation efficiency of crystal was found to be 1.5 times to that of KDP. From thermo gravimetric analysis and differential thermal analysis, thermal stability and melting point (246 °C) were investigated. The dielectric behavior, optical characterization, piezoelectric behavior and the non-linear optical properties of the Bisglycine Lithium Nitrate single crystals were reported for the first time which established the usefulness of these crystals for various piezo- and opto-electronics applications.

Dalal, Jyoti; Sinha, Nidhi; Kumar, Binay

2014-11-01

23

21 CFR 73.165 - Ferrous lactate.  

Code of Federal Regulations, 2011 CFR

...2011-04-01 2011-04-01 false Ferrous lactate. 73.165 Section 73.165 Food...CERTIFICATION Foods § 73.165 Ferrous lactate. (a) Identity. The color additive ferrous lactate is the ferrous lactate defined in §...

2011-04-01

24

21 CFR 73.165 - Ferrous lactate.  

Code of Federal Regulations, 2013 CFR

...2013-04-01 2013-04-01 false Ferrous lactate. 73.165 Section 73.165 Food...CERTIFICATION Foods § 73.165 Ferrous lactate. (a) Identity. The color additive ferrous lactate is the ferrous lactate defined in §...

2013-04-01

25

21 CFR 73.165 - Ferrous lactate.  

Code of Federal Regulations, 2014 CFR

...2014-04-01 2014-04-01 false Ferrous lactate. 73.165 Section 73.165 Food...CERTIFICATION Foods § 73.165 Ferrous lactate. (a) Identity. The color additive ferrous lactate is the ferrous lactate defined in §...

2014-04-01

26

21 CFR 73.165 - Ferrous lactate.  

Code of Federal Regulations, 2012 CFR

...2012-04-01 2012-04-01 false Ferrous lactate. 73.165 Section 73.165 Food...CERTIFICATION Foods § 73.165 Ferrous lactate. (a) Identity. The color additive ferrous lactate is the ferrous lactate defined in §...

2012-04-01

27

21 CFR 73.165 - Ferrous lactate.  

Code of Federal Regulations, 2010 CFR

...2010-04-01 2010-04-01 false Ferrous lactate. 73.165 Section 73.165 Food...CERTIFICATION Foods § 73.165 Ferrous lactate. (a) Identity. The color additive ferrous lactate is the ferrous lactate defined in §...

2010-04-01

28

Chelation Therapy  

MedlinePLUS

... about its benefits. The ACAM agreed to stop publishing any claims that were not based on reliable ... other than heavy-metal poisoning. There are no published studies that reliably show benefit from using chelation ...

29

Ferrous iron is transported across the peribacteroid membrane of soybean nodules  

Microsoft Academic Search

.   Symbiosomes and bacteroids isolated from soybean (Glycine max Merr.) nodules are able to take up ferrous iron. This uptake activity was completely abolished in the presence of ferrous-iron\\u000a chelators. The kinetics of uptake were characterized by initially high rates of iron internalization, but no saturation was\\u000a observed with increasing iron concentration. This process does not appear to involve the

Sophie Moreau; David A. Day; Alain Puppo

1998-01-01

30

21 CFR 184.1315 - Ferrous sulfate.  

Code of Federal Regulations, 2010 CFR

... O, CAS Reg. No. 7782-63-0) is prepared by the action of sulfuric acid on iron. It occurs as pale, bluish-green crystals or granules. Progressive heating of ferrous sulfate heptahydrate produces ferrous sulfate (dried). Ferrous...

2010-04-01

31

[Effectiveness of different iron supplementation strategies on hemoglobin and ferritin levels among schoolchildren in Teresina, Piauí State, Brazil].  

PubMed

This study evaluated the effectiveness of supplementation with ferrous sulfate and iron bis-glycinate chelate on hemoglobin and serum ferritin levels among schoolchildren (7-11 years) of both sexes. A randomized community-based trial including 138 anemic children (hemoglobin < 11.5 g/dL) was conducted in Teresina, Piauí State, Brazil. Children were assigned to two treatment groups on an individual basis. One group (n = 71) received 40 mg iron as ferrous sulfate once weekly and the other group (n = 67) received 3.8 mg of iron bis-glycinate chelate-enriched cookies, 3x/week, for 8 weeks. The interventions showed a significant increase (p < 0.01) in hemoglobin levels (1.1g/dL) for children who received ferrous sulfate and 0.9 g/dl in those who received iron bis-glycinate chelate, although not significant in the inter-group comparison (p > 0.05). No effect was observed on body iron for either intervention (p > 0.05). Children with depleted iron stores (< 15 ng/mL) at the beginning of interventions showed increased serum ferritin concentrations after 8 weeks (p < 0.01), although no difference between treatments (p > 0.05) was observed. The results confirm the effectiveness of the iron supplementation interventions and corroborate the use of iron salts or ferrous bisglycinate chelate on a weekly basis to overcome iron deficiency and anemia. PMID:17572803

Dos Santos, Marize Melo; Nogueira, Nadir do Nascimento; Diniz, Alcides da Silva

2007-07-01

32

Hydroxyl radicals cause fluctuation in intracellular ferrous ion levels upon light exposure during photoreceptor cell death.  

PubMed

Iron accumulation is a potential pathogenic event often seen in age-related macular degeneration (AMD) patients. In this study, we focused on the relationship between AMD pathology and concentrations of ferrous ion, which is a highly reactive oxygen generator in biological systems. Murine cone-cells-derived 661 W cells were exposed to white fluorescence light at 2500 lx for 1, 3, 6, or 12 h. Levels of ferrous ions, reactive oxygen species (ROS), and hydroxyl radicals were detected by RhoNox-1, a novel fluorescent probe for the selective detection of ferrous ion, 5-(and-6)-chloromethyl-2',7'-dichlorodihydrofluorescein diacetate, acetyl ester (CM-H2DCFDA), and 3'-p-(aminophenyl) fluorescein, respectively. Reduced glutathione, total iron levels and photoreceptor cell death were also measured. Two genes related to iron metabolism, transferrin receptor 1 (TfR1) and H ferritin (HFt), were quantified by RT-PCR. The effects of ferrous ion on cell death and hydroxyl radical production were determined by treatment with a ferrous ion chelating agent, 2,2'-bipyridyl. We found that the ferrous ion level decreased with light exposure in the short time frame, whereas it was upregulated during a 6-h light exposure. Total iron, ROS, cell death rate, and expression of TfR and HFt genes were significantly increased in a time-dependent manner in 661 W cells exposed to light. Chelation with 2,2'-bipyridyl reduced the level of hydroxyl radicals and protected against light-induced cell death. These results suggest that light exposure decreases ferrous ion levels and enhances iron uptake in photoreceptor cells. Ferrous ion may be involved in light-induced photoreceptor cell death through production of hydroxyl radicals. PMID:25447561

Imamura, Tomoyo; Hirayama, Tasuku; Tsuruma, Kazuhiro; Shimazawa, Masamitsu; Nagasawa, Hideko; Hara, Hideaki

2014-12-01

33

Efficacy and safety of ferrous asparto glycinate in the management of iron deficiency anaemia in pregnant women.  

PubMed

The aim of the present investigation was to compare the efficacy and safety of oral ferrous asparto glycinate and ferrous ascorbate in pregnant women with iron deficiency anaemia (IDA). We performed a double blind, prospective, randomised, multicentre, parallel group comparative clinical study at three different centres in India. A total of 73 pregnant women at 12-26 weeks' gestation were divided into two arms. While one group received ferrous ascorbate, another group was treated with ferrous asparto glycinate for a period of 28 days. The mean rise in haemoglobin and ferritin levels on day 14 and 28 was evaluated. At both time points, significantly higher levels of haemoglobin and ferritin were noticed with ferrous asparto glycinate treatment as compared with ferrous ascorbate. Our results showed that ferrous asparto glycinate is an effective iron-amino acid chelate in the management of IDA in pregnant women as compared with ferrous ascorbate. Nevertheless, additional large scale prospective, randomised trials are warranted to confirm the findings of the present efficacy trial, and also to find out the anaemia eradication rate. PMID:24959663

Kamdi, S P; Palkar, P J

2015-01-01

34

21 CFR 184.1311 - Ferrous lactate.  

Code of Federal Regulations, 2011 CFR

...reacting calcium lactate or sodium lactate with ferrous sulfate, direct reaction of lactic acid with iron filings...chloride with sodium lactate, or reaction of ferrous sulfate with ammonium lactate. (b) The ingredient meets...

2011-04-01

35

21 CFR 184.1311 - Ferrous lactate.  

Code of Federal Regulations, 2014 CFR

...reacting calcium lactate or sodium lactate with ferrous sulfate, direct reaction of lactic acid with iron filings...chloride with sodium lactate, or reaction of ferrous sulfate with ammonium lactate. (b) The ingredient meets...

2014-04-01

36

21 CFR 184.1311 - Ferrous lactate.  

Code of Federal Regulations, 2013 CFR

...reacting calcium lactate or sodium lactate with ferrous sulfate, direct reaction of lactic acid with iron filings...chloride with sodium lactate, or reaction of ferrous sulfate with ammonium lactate. (b) The ingredient meets...

2013-04-01

37

21 CFR 184.1311 - Ferrous lactate.  

Code of Federal Regulations, 2012 CFR

...reacting calcium lactate or sodium lactate with ferrous sulfate, direct reaction of lactic acid with iron filings...chloride with sodium lactate, or reaction of ferrous sulfate with ammonium lactate. (b) The ingredient meets...

2012-04-01

38

21 CFR 184.1311 - Ferrous lactate.  

Code of Federal Regulations, 2010 CFR

...reacting calcium lactate or sodium lactate with ferrous sulfate, direct reaction of lactic acid with iron filings...chloride with sodium lactate, or reaction of ferrous sulfate with ammonium lactate. (b) The ingredient meets...

2010-04-01

39

21 CFR 184.1308 - Ferrous gluconate.  

Code of Federal Regulations, 2013 CFR

...greenish-yellow powder or granules. It is prepared by reacting hot solutions of barium or calcium gluconate with ferrous sulfate or by heating freshly prepared ferrous carbonate with gluconic acid in aqueous solution. (b) The ingredient...

2013-04-01

40

Effect of iron chelators on placental uptake and transfer of iron in rat  

SciTech Connect

The uptake of radiolabeled transferrin and iron by the rat placenta has been studied using two approaches. The first involved injection of a ferrous or ferric iron chelator followed by injection of label. Neither chelator decreased the amount of labelled transferrin in the placenta after 2-h incubation and only bipyridine, a ferrous iron chelator, inhibited iron transport to the fetus. Deferoxamine (DFO), a ferric iron chelator, had no effect on iron transport to the fetus but reduced iron uptake by the liver. Both bipyridine and DFO increased iron excretion into the gut and by the urinary tract to the same degree into the gut, but there was a 10-fold greater urinary excretion with bipyridine than with DFO. Injection of iron attached to the chelators showed that neither bipyridine nor DFO could donate iron to the fetus as efficiently as transferrin. The mechanism involved was further investigated by studying the effect of the chelators on uptake of transferrin-bound iron by placental cells in culture. DFO inhibited iron accumulation more effectively than bipyridine in the cultured cells. The effect was not due to a decrease in the cycling time of the receptor. The results can be explained if the iron is released from the transferrin in intracellular vesicles in the ferrous form, where it may be chelated by bipyridine and prevented from passing to the fetus or converted to the ferric form once it is inside the cell matrix.

Wong, C.T.; McArdle, H.J.; Morgan, E.H.

1987-05-01

41

46 CFR 148.260 - Ferrous metal.  

Code of Federal Regulations, 2011 CFR

...2011-10-01 2011-10-01 false Ferrous metal. 148.260 Section 148.260 Shipping...Certain Materials § 148.260 Ferrous metal. (a) This part does not apply...waters of United States. (b) Ferrous metal may not be stowed or transported in...

2011-10-01

42

46 CFR 148.260 - Ferrous metal.  

Code of Federal Regulations, 2014 CFR

...2014-10-01 2014-10-01 false Ferrous metal. 148.260 Section 148.260 Shipping...Certain Materials § 148.260 Ferrous metal. (a) This part does not apply...waters of United States. (b) Ferrous metal may not be stowed or transported in...

2014-10-01

43

46 CFR 148.260 - Ferrous metal.  

Code of Federal Regulations, 2012 CFR

...2012-10-01 2012-10-01 false Ferrous metal. 148.260 Section 148.260 Shipping...Certain Materials § 148.260 Ferrous metal. (a) This part does not apply...waters of United States. (b) Ferrous metal may not be stowed or transported in...

2012-10-01

44

46 CFR 148.260 - Ferrous metal.  

Code of Federal Regulations, 2013 CFR

...2013-10-01 2013-10-01 false Ferrous metal. 148.260 Section 148.260 Shipping...Certain Materials § 148.260 Ferrous metal. (a) This part does not apply...waters of United States. (b) Ferrous metal may not be stowed or transported in...

2013-10-01

45

Mineral resource of the month: ferrous slag  

USGS Publications Warehouse

The article offers information on mineral resource ferrous slag. Ferrous slag is produced through the addition of materials such as limestone and dolomite to blast and steel furnaces to remove impurities from iron ore and to lower the heat requirements for processes in iron and steel making. It is stated that the method of cooling is important for the market uses and value of ferrous slag. Some types of slag can be used in construction, glass manufacturing and thermal insulation.

U.S. Geological Survey

2009-01-01

46

A preliminary study of the bio availability of iron? and zinc?glycine chelates  

Microsoft Academic Search

Groups of rats were fed diets containing marginal levels of Fe and Zn as glycine chelates (tradename ‘Chelazome’, Albion Laboratories, Verona, New Jersey, USA), or the same level of mineral as ferrous sulphate or zinc carbonate. The Fe diets were fed to weanling rats for 4 weeks and the Zn diets to young adult rats for 5 weeks. Blood Hb

Thomas E. Fox; S. Gabrielle Wharf; Nawalyah A. Ghani

1992-01-01

47

Chelation in Metal Intoxication  

PubMed Central

Chelation therapy is the preferred medical treatment for reducing the toxic effects of metals. Chelating agents are capable of binding to toxic metal ions to form complex structures which are easily excreted from the body removing them from intracellular or extracellular spaces. 2,3-Dimercaprol has long been the mainstay of chelation therapy for lead or arsenic poisoning, however its serious side effects have led researchers to develop less toxic analogues. Hydrophilic chelators like meso-2,3-dimercaptosuccinic acid effectively promote renal metal excretion, but their ability to access intracellular metals is weak. Newer strategies to address these drawbacks like combination therapy (use of structurally different chelating agents) or co-administration of antioxidants have been reported recently. In this review we provide an update of the existing chelating agents and the various strategies available for the treatment of heavy metals and metalloid intoxications. PMID:20717537

Flora, Swaran J.S.; Pachauri, Vidhu

2010-01-01

48

Macrocyclic bifunctional chelating agents  

DOEpatents

A copper chelate conjugate which is stable in human serum. The conjugate includes the copper chelate of a cyclic tetraaza di-, tri-, or tetra-acetic acid, a linker attached at one linker end to a ring carbon of the chelate, and a biomolecule joined at the other end of the linker. The conjugate, or the linker-copper chelate compound used in forming the conjugate, are designed for use in diagnostic and therapeutic applications which involve Cu(II) localization via the systemic route.

Meares, Claude F. (Davis, CA); DeNardo, Sally J. (El Macero, CA); Cole, William C. (Houston, TX); Mol, Min K. (Davis, CA)

1987-01-01

49

The Rules of Ferrous Metallurgy  

PubMed Central

The ways in which the sciences have been delineated and categorized throughout history provide insights into the formation, stabilization, and establishment of scientific systems of knowledge. The Dresdener school’s approach for explaining and categorizing the genesis of the engineering disciplines is still valid, but needs to be complemented by further-reaching methodological and theoretical reflections. Pierre Bourdieu’s theory of social practice is applied to the question of how individual agents succeed in influencing decisively a discipline’s changing object orientation, institutionalisation and self-reproduction. Through the accumulation of social, cultural and economic capital, they succeed in realising their own organisational ideas and scientific programs. Key concepts for the analysis include the struggle for power and resources, monopolies of interpretation, and the degree of autonomy. A case study from the Aachener Technische Hochschule shows that the consolidation of ferrous metallurgy can be conceived as a symbolical struggle between Fritz Wüst, professor for ferrous metallurgy, and the German Iron and Steel Institute, leading to a construction of a system of differences in which scientists accepted being scientists rather than entrepreneurs, and entrepreneurs accepted becoming entrepreneurs and renounced science.

2010-01-01

50

21 CFR 184.1308 - Ferrous gluconate.  

Code of Federal Regulations, 2011 CFR

...6047-12-7) is a fine yellowish-gray or pale greenish-yellow powder or granules. It is prepared by reacting hot solutions of barium or calcium gluconate with ferrous sulfate or by heating freshly prepared ferrous carbonate with gluconic acid in aqueous...

2011-04-01

51

Ferrous iron transport in Streptococcus mutans  

SciTech Connect

Radioiron uptake from /sup 59/FeCl/sub 3/ by Streptococcus mutans OMZ176 was increased by anaerobiosis, sodium ascorbate, and phenazine methosulfate (PMS), although there was a 10-min lag before PMS stimulation was evident. The reductant ascorbate may have provided ferrous iron. The PMS was reduced by the cells, and the reduced PMS then may have generated ferrous iron for transport; reduced PMS also may have depleted dissolved oxygen. It was concluded that S. mutans transports only ferrous iron, utilizing reductants furnished by glucose metabolism to reduce iron prior to its uptake.

Evans, S.L.; Arcenaeux, J.E.L.; Byers, B.R.; Martin, M.E.; Aranha, H.

1986-12-01

52

Ferrous iron oxidation by anoxygenic phototrophic bacteria  

Microsoft Academic Search

NATURAL oxidation of ferrous to ferric iron by bacteria such as Thiobacillus ferrooxidans or Gallionella ferruginea1, or by chemical oxidation2,3 has previously been thought always to involve molecular oxygen as the electron acceptor. Anoxic photochemical reactions4-6 or a photobiological process involving two photosystems7-9 have also been discussed as mechanisms of ferrous iron oxidation. The knowledge of such processes has implications

Friedrich Widdel; Sylvia Schnell; Silke Heising; Armin Ehrenreich; Bernhard Assmus; Bernhard Schink

1993-01-01

53

Iron chelation, quo vadis?  

PubMed

Orally bioavailable chelators for transfusional iron overload have been sought since the introduction of deferoxamine (Desferal) in 1962. Despite tremendous efforts, to date, only deferiprone (Ferriprox) and deferasirox (Exjade) have successfully reached the market, reflecting the difficulty to combine oral activity and safety. Owing to the risk of failure, few new oral chelators can be expected in the future for the treatment of transfusional iron overload. As iron is involved in many disease processes, deferiprone and deferasirox have been proposed to be potentially useful in a variety of indications not characterized by general iron overload. Although it may be possible to obtain clinical benefit from current compounds, more selective chelators tailored to the particular target are needed for successful intervention in these indications. PMID:17644021

Nick, Hanspeter

2007-08-01

54

Iron Chelation Therapy  

MedlinePLUS

... in a moderate dose, such as 100 mg daily. One additional iron chelator is currently being used in Europe, Asia, and Canada, but is not yet approved by the FDA for use in the United States: Deferiprone or L1 (FerriproxTM) comes in a pill form and is taken 3 times a day. ...

55

Rigid bifunctional chelating agents  

DOEpatents

Bicyclo[2.2.2] octane-2,3 diamine-N,N,N`,N`-tetraacetic acids (BODTA) and bicyclo[2.2.1] heptane-2,3 diamine-N,N,N`,N`-tetraacetic acid (BHDTA) are chelating agents useful in forming detectably labeled bioconjugate compounds for diagnostic and therapeutic purposes. New compounds and processes of forming BODTA and BHDTA are disclosed. Radioimmunoconjugates of the present invention show high and prolonged tumor uptake with low normal tissue uptakes.

Sweet, M.P.; Mease, R.C.; Srivastava, S.C.

1998-07-21

56

Rigid bifunctional chelating agents  

DOEpatents

Bicyclo[2.2.2]octane-2,3 diamine-N,N,N',N'-tetraacetic acids (BODTA) and bicyclo[2.2.1]heptane-2,3 diamine-N,N,N',N'-tetraacetic acid (BHDTA) are chelating agents useful in forming detectably labeled bioconjugate compounds for diagnostic and therapeutic purposes. New compounds and processes of forming BODTA and BHDTA are disclosed. Radioimmunoconjugates of the present invention show high and prolonged tumor uptake with low normal tissue uptakes.

Sweet, Mark P. (Coram, NY); Mease, Ronnie C. (Fairfax, VA); Srivastava, Suresh C. (Setauket, NY)

2000-02-08

57

Rigid bifunctional chelating agents  

DOEpatents

Bicyclo›2.2.2! octane-2,3 diamine-N,N,N',N'-tetraacetic acids (BODTA) and bicyclo›2.2.1! heptane-2,3 diamine-N,N,N',N'-tetraacetic acid (BHDTA) are chelating agents useful in forming detectably labeled bioconjugate compounds for diagnostic and therapeutic purposes. New compounds and processes of forming BODTA and BHDTA are disclosed. Radioimmunoconjugates of the present invention show high and prolonged tumor uptake with low normal tissue uptakes.

Sweet, Mark P. (Coram, NY); Mease, Ronnie C. (Fairfax, VA); Srivastava, Suresh C. (Setauket, NY)

1998-07-21

58

A comparison of the bioavailability of ferrous fumarate and ferrous sulfate in non-anemic Mexican women and children consuming a sweetened maize and milk drink  

Microsoft Academic Search

Background\\/Objectives:Ferrous fumarate is recommended for the fortification of complementary foods based on similar iron absorption to ferrous sulfate in adults. Two recent studies in young children have reported that it is only 30% as well absorbed as ferrous sulfate. The objective of this study was to compare iron absorption from ferrous fumarate and ferrous sulfate in infants, young children and

M Harrington; C Hotz; C Zeder; G O Polvo; S Villalpando; M B Zimmermann; T Walczyk; J A Rivera; R F Hurrell

2011-01-01

59

Combined SOâ\\/NOâ control using ferrous·EDTA and a secondary additive in a lime-based aqueous scrubber system  

Microsoft Academic Search

Integration of NOâ control into existing flue-gas desulfurization (FGD) systems addresses site-specific control requirements while minimizing retrofit difficulties. Argonne has studied the use of the metal-chelate additives, such as ferrous·EDTA in various wet FGD chemistries, to promote combined SOâ\\/NOâ scrubbing. A major process problem is oxidation of the iron to the ferric species, leading to a significant decrease in NOâ-removal

M. H. Mendelsohn; C. D. Livengood; J. B. L. Harkness

1991-01-01

60

Metal Chelating Crosslinkers Form Nanogels with High Chelation Stability  

PubMed Central

We present a series of hydrogel nanoparticles (nanogels) incorporating either acyclic or cyclic metal chelates as crosslinkers. These crosslinkers are used to formulate polyacrylamide-based nanogels (diameter 50 to 85 nm) yielding contrast agents with enhanced relaxivities (up to 6-fold greater than Dotarem®), because this nanogel structure slows the chelator's tumbling frequency and allows fast water exchange. Importantly, these nanogels also stabilize Gd3+ within the chelator thermodynamically and kinetically against metal displacement through transmetallation, which should reduce toxicity associated with release of free Gd3+. This chelation stability suggests that the chelate crosslinker strategy may prove useful for other applications of metal-chelating nanoparticles in medicine, including other imaging modalities and radiotherapy. PMID:24505553

Elst, Luce Vander; Schopf, Eric; Mahmoud, Enas; Laurent, Sophie; Almutairi, Adah

2013-01-01

61

Removal of copper from ferrous scrap  

DOEpatents

A process for removing copper from ferrous or other metal scrap in which the scrap is contacted with a polyvalent metal sulfide slag in the presence of an excess of copper-sulfide forming additive to convert the copper to copper sulfide which is extracted into the slag to provide a ratio of copper in the slag to copper in the metal scrap of at least about 10.

Blander, M.; Sinha, S.N.

1987-07-30

62

Removal of copper from ferrous scrap  

DOEpatents

A process for removing copper from ferrous or other metal scrap in which the scrap is contacted with a polyvalent metal sulfide slag in the presence of an excess of copper-sulfide forming additive to convert the copper to copper sulfide which is extracted into the slag to provide a ratio of copper in the slag to copper in the metal scrap of at least about 10.

Blander, M.; Sinha, S.N.

1990-05-15

63

Use of ferrous chelates for NO sub x control in aqueous scrubbers  

Microsoft Academic Search

Argonne National Laboratory has been conducting research on combined NOâ\\/SOâ control systems for the US Department of Energy since 1981. Recently, the research program has been focused on aqueous scrubber systems and has involved studies on NOâ removal through chemical additives based on Argonne's patented ARGONOX additives. Tests have been conducted in laboratory-scale aqueous scrubbers of two types. The experimental

C. D. Livengood; J. B. L. Harkness; M. H. Mendelsohn

1990-01-01

64

Chelation of cadmium.  

PubMed Central

The toxicity of cadmium is determined by chelation reactions: in vivo, Cd2+ exists exclusively in coordination complexes with biological ligands, or with administered chelating agents. The Cd2+ ion has some soft character, but it is not a typical soft ion. It has a high degree of polarizability, and its complexes with soft ligands have predominantly covalent bond characteristics. Cd2+ forms the most stable complexes with soft donor atoms (S much greater than N greater than 0). The coordination stereochemistry of Cd2+ is unusually varied, including coordination numbers from 2 to 8. Even though the Cd2+ ion is a d10 ion, disturbed coordination geometries are often seen. Generally, the stability of complexes increases with the number of coordination groups contributed by the ligand; consequently, complexes of Cd2+ with polydentate ligands containing SH groups are very stable. Cd2+ in metallothionein (MT) is coordinated with 4 thiolate groups, and the log stability constant is estimated to 25.5. Complexes between Cd2+ and low molecular weight monodentate or bidentate ligands, e.g., free amino acids (LMW-Cd), seem to exist very briefly, and Cd2+ is rapidly bound to high molecular weight proteins, mainly serum albumin. These complexes (HMW-Cd) are rapidly scavenged from blood, mainly by the liver, and Cd2+ is redistributed to MT. After about 1 day the Cd-MT complex (MT-Cd) almost exclusively accounts for the total retained dose of Cd2+, independent of the route of exposure. MT-Cd is slowly transferred to and accumulated in kidney cortex. The acute toxicity and interorgan distribution of parenterally administered Cd2+ are strongly influenced by preceding MT induction, or decreased capacity for MT synthesis; however, the gastrointestinal (GI) uptake of Cd2+ seems unaffected by preceding MT induction resulting in considerable capacity for Cd2+ chelation in intestinal mucosa, and this finding indicates that endogenous MT is not involved in Cd2+ absorption. The toxicity of parenterally administered Cd2+ is strongly enhanced when administered as complexes with NTA or STPP , but it is much decreased when administered as a complex with EDTA. In chronic oral exposure the toxicity and GI uptake of Cd2+ is not changed when Cd2+ is administered as a complex with the detergent formula chelating agents NTA, EDTA and STPP . The uptake of Cd2+ from ligated intestine in vivo was not affected by administration of Cd2+ as complexes with CYS or GSH, but significantly reduced by complexation with EDTA or BAL. The acute toxicity of orally administered Cd2+ is reduced when Cd2+ is administered as a complex with EDTA.(ABSTRACT TRUNCATED AT 400 WORDS) PMID:6734560

Andersen, O

1984-01-01

65

Antioxidant Potential ofEcklonia cavaon Reactive Oxygen Species Scavenging, Metal Chelating, Reducing Power and Lipid Peroxidation Inhibition  

Microsoft Academic Search

The antioxidative potential of different fractions (respective organic and aqueous fractions of n-hexane, chloroform and ethyl acetate) of 70% methanol extract of Ecklonia cava(a brown seaweed) was evaluated using 1,1-diphenyl-2-picrylhydrazyl (DPPH), superoxide anion, hydrogen peroxide, hydroxyl radical, nitric oxide, ferrous ion chelating, reducing power and lipid peroxidation inhibition (conjugated diene hydroperoxide and thiobarbituric acid-reactive substances production) assays. The 70% methanol

Mahinda Senevirathne; Soo-Hyun Kim; Nalin Siriwardhana; Jin-Hwan Ha; Ki-Wan Lee; You-Jin Jeon

2006-01-01

66

Preparation and pH stability of ferrous glycinate liposomes.  

PubMed

Ferrous glycinate liposomes were prepared by reverse phase evaporation method. The effects of cholesterol, Tween 80, ferrous glycinate concentration, hydrating medium, pH of hydrating medium, and sonication strength on the encapsulation efficiency of liposomes were investigated. Encapsulation efficiency was significantly influenced by the different technique parameters. Ferrous glycinate liposomes might be obtained with high encapsulation efficiency of 84.80% under the conditions of optimized technique parameters. The zeta potential and average particle size of liposomes in the hydrating medium of pH 7.0 were 9.6 mV and 559.2 nm, respectively. The release property of ferrous glycinate liposomes in vitro was investigated in simulated gastrointestinal juice. A small amount of ferrous glycinate was released from liposomes in the first 4 h in simulated gastrointestinal juice. The mean diameters of liposomes increased from 559.2 to 692.9, 677.8, and 599.3 nm after incubation in simulated gastrointestinal juice of pH 1.3, 7.5, and 7.5 in the presence of bile salts, respectively. Results showed that the stability of ferrous glycinate in strong acid environment was greatly improved by encapsulation in liposomes, which protected ferrous glycinate from disrupting the extracapsular environment by lipid bilayer. The bioavailability of ferrous glycinate, as the iron source for biological activity including hemoglobin formation, may be increased. The ferrous glycinate liposomes may be a kind of promising iron fortifier. PMID:19253959

Ding, Baomiao; Xia, Shuqin; Hayat, Khizar; Zhang, Xiaoming

2009-04-01

67

Polycatecholamide chelating agents  

DOEpatents

Novel polybenzamide compounds useful for in vitro or in vivo chelation are described. The compounds have the formula ##STR1## Polyamines are reacted with 2,3-dimethoxy benzoyl chloride unsubstituted or substituted with SO.sub.3 H, SO.sub.3 M, NO.sub.2, CO.sub.2 H or CO.sub.2 M as desired is reacted with a polyamine in an inert solvent then demethylated with BBr.sub.3 or BCl.sub.3 in an inert solvent. Where compounds symmetrically substituted on the terminal N's are desired, the polyamine is first reductively alkylated by reaction with an aldehyde or ketone and the resulting Schiff base is hydrogenated.

Weitl, Frederick L. (Martinez, CA); Raymond, Kenneth N. (Berkeley, CA)

1984-01-01

68

Polycatecholamide chelating agents  

DOEpatents

Novel polybenzamide compounds useful for in vitro or in vivo chelation are described. The compounds have the formula given in patent. Polyamines are reacted with 2,3-dimethoxy benzoyl chloride unsubstituted or substituted with SO[sub 3]H, SO[sub 3]M, NO[sub 2], CO[sub 2]H or CO[sub 2]M as desired is reacted with a polyamine in an inert solvent then demethylated with BBr[sub 3] or BCl[sub 3] in an inert solvent. Where compounds symmetrically substituted on the terminal N's are desired, the polyamine is first reductively alkylated by reaction with an aldehyde or ketone and the resulting Schiff base is hydrogenated. No Drawings

Weitl, F.L.; Raymond, K.N.

1984-04-10

69

Novel polycatecholamide chelating agents  

DOEpatents

Novel polybenzamide compounds useful for in vitro or in vivo chelation are described. Formulas of the compounds are given. To prepare them polyamines are reacted with 2,3-dimethoxy benzoyl chloride unsubstituted or substituted with SO/sub 3/H, SO/sub 3/M, NO/sub 2/, CO/sub 2/H or CO/sub 2/M as desired is reacted with a polyamine in an inert solvent then demethylated with BBr/sub 3/ or BCl/sub 3/ in an inert solvent. Where compounds symmetrically substituted on the terminal N's are desired, the polyamine is first reductively alkylated by reaction with an aldehyde or ketone and the resulting Schiff base is hydrogenated.

Weitl, F.L.; Raymond, K.N.

1981-08-24

70

Ferrous-activated persulfate oxidation of arsenic(III) and diuron in aquatic system.  

PubMed

In situ chemical oxidation (ISCO) can be an effective technology for the remediation of soil and groundwater polluted by organic and inorganic contaminants. This study investigated the oxidation of arsenic(III) (As(III)) and diuron using ferrous activated persulfate-based ISCO. The results indicated that Fe(II)/persulfate oxidation could be an effective method to oxidize As(III) and diuron. Effects of pH, S2O8(2-) and Fe(II) amounts on the destruction of As(III) and diuron were examined in batch experiments. Acidic conditions favored the removal of As(III) and diuron. Four chelating agents, citric acid (CA), Na2S2O3, diethylene triamine pentaacetic acid (DTPA) and ethylene diamine tetraacetic acid disodium (EDTA-Na2) were used in attempt to maintain the quantity of ferrous ion in solution. In our experiments, CA and Na2S2O3 were found to be more effective than DTPA and EDTA-Na2. Our results also revealed a widely practical prospect of inorganic chelating agent Na2S2O3. Hydroxyl and sulfate radical were determined to play key roles in the oxidation process by using ethanol and tertiary butanol as molecular probes. Oxidation of As(III) yielded As(V) via the electron-transfer reaction. In the oxidation process of diuron, a stepwise nucleophilic substitution of chlorine by hydroxyl and a stepwise oxidation process of the methyl on the dimethylurea group by hydroxyl and sulfate radical were proposed. PMID:24220194

Zhou, Lei; Zheng, Wei; Ji, Yuefei; Zhang, Jinfeng; Zeng, Chao; Zhang, Ya; Wang, Qi; Yang, Xi

2013-12-15

71

46 CFR 148.04-13 - Ferrous metal borings, shavings, turnings, or cuttings (excluding stainless steel).  

Code of Federal Regulations, 2010 CFR

...2010-10-01 2010-10-01 false Ferrous metal borings, shavings, turnings, or cuttings...Certain Material § 148.04-13 Ferrous metal borings, shavings, turnings, or cuttings...hazardous materials described as ferrous metal borings, shavings, turnings,...

2010-10-01

72

Continuous ferrous iron biooxidation in flooded packed bed reactors  

Microsoft Academic Search

In this paper the biological ferrous iron oxidation in flooded packed bed reactors is studied. Bacterial oxidation of ferrous iron is a potential industrial process for the treatment of acid mine drainage and in the regeneration of ferric iron as a leaching agent in hydrometallurgical processes.The aim of this work is the development of a reactor capable of attaining the

A. Mazuelos; R. Romero; I. Palencia; N. Iglesias; F. Carranza

1999-01-01

73

Separate pathways for cellular uptake of ferric and ferrous iron.  

PubMed

Separate pathways for transport of nontransferrin ferric and ferrous iron into tissue cultured cells were demonstrated. Neither the ferric nor ferrous pathway was shared with either zinc or copper. Manganese shared the ferrous pathway but had no effect on cellular uptake of ferric iron. We postulate that ferric iron was transported into cells via beta(3)-integrin and mobilferrin (IMP), whereas ferrous iron uptake was facilitated by divalent metal transporter-1 (DMT-1; Nramp-2). These conclusions were documented by competitive inhibition studies, utilization of a beta(3)-integrin antibody that blocked uptake of ferric but not ferrous iron, development of an anti-DMT-1 antibody that blocked ferrous iron and manganese uptake but not ferric iron, transfection of DMT-1 DNA into tissue culture cells that showed enhanced uptake of ferrous iron and manganese but neither ferric iron nor zinc, hepatic metal concentrations in mk mice showing decreased iron and manganese but not zinc or copper, and data showing that the addition of reducing agents to tissue culture media altered iron binding to proteins of the IMP and DMT-1 pathways. Although these experiments show ferric and ferrous iron can enter cells via different pathways, they do not indicate which pathway is dominant in humans. PMID:11005764

Conrad, M E; Umbreit, J N; Moore, E G; Hainsworth, L N; Porubcin, M; Simovich, M J; Nakada, M T; Dolan, K; Garrick, M D

2000-10-01

74

Hydroxypyridonate chelating agents and synthesis thereof  

DOEpatents

Chelating agents having 1-hydroxy-2-pyridinone (HOPO) and related moieties incorporated within their structures, including polydentate HOPO-substituted polyamines such as spermidine and spermine, and HOPO-substituted desferrioxamine. The chelating agents are useful in selectively removing certain cations from solution, and are particularly useful as ferric ion and actinide chelators. Novel syntheses of the chelating agents are provided. 4 tabs.

Raymond, K.N.; Scarrow, R.C.; White, D.L.

1985-11-12

75

Evaluation of CYP450 inhibitory effects and steady-state pharmacokinetics of genistein in combination with cholecalciferol and citrated zinc bisglycinate in postmenopausal women  

PubMed Central

Background The combination of genistein 27 mg, cholecalciferol 200 IU, citrated zinc bisglycinate (4 mg elemental zinc) 20 mg per capsule in Fosteum®, a prescription medical food regulated by the FDA and indicated for the dietary management of osteopenia and osteoporosis, was tested for drug interactions and to determine the pharmacokinetic profile for genistein, the principal bone-modulating ingredient in the product. Methods In vitro human liver microsome cytochrome P450 (CYP450) assays were used to test the product for potential drug interactions with the isoforms 1A2, 2C8, 2C9, 2C19, 2D6, and 3A4. Due to specific 2C8 and 2C9 inhibition, a steady-state pharmacokinetic study was performed to assess serum genistein concentrations by high-pressure liquid chromatography-coupled mass spectroscopy in healthy fasting (n = 10) and fed (n = 10) postmenopausal women. Results The product showed minimal inhibition of 1A2, 2C19, 2D6, and 3A4, exhibiting IC50 > 10 ?M, but 2C8 and 2C9 yielded IC50 of 2.5 ?M and 2.8 ?M, respectively, concentrations which are theroretically achievable when dosing the product twice daily. After seven days of administration in a steady-state pharmacokinetic study, significant differences were found for unconjugated genistein (including free and protein-bound), regarding time to peak concentration (1.88 ± 1.36 hours), maximum concentration reached (0.052 ± 0.055 ?M), elimination half-life (2.3 ± 1.6 hours), and area under the concentration-time curve (53.75 ± 17.59 ng · hour/mL) compared with results for total genistein (including glucuronidated and sulfonated conjugates) time to peak concentration (2.22 ± 1.09 hours), maximum concentration reached (2.95 ± 1.64 ?M), elimination half-life (10.4 ± 4.1 hours), and area under the concentration-time curve (10424 ± 6290 ng · hour/mL) in fasting subjects. Coadministration of food tended to extend the time and extent of absorption as well as slow elimination of genistein, but not in a statistically significant manner. Conclusion Because the serum genistein concentrations achieved during pharmacokinetic testing at therapeutic doses were well below those required for enzyme inhibition in the in vitro liver microsome assays, these results indicate a low potential for drug interactions. PMID:21792336

Burnett, Bruce P; Pillai, Lakshmi; Bitto, Alessandra; Squadrito, Francesco; Levy, Robert M

2011-01-01

76

Induction of Porphyrin Synthesis in Etiolated Bean Leaves by Chelators of Iron 12  

PubMed Central

Primary leaves of 7- to 9-day-old etiolated seedlings of Phaseolus vulgaris L. var. Red Kidney infiltrated in darkness with aqueous solutions of ?, ??-dipyridyl, o-phenanthroline, pyridine-2-aldoxime, pyridine-2-aldehyde, 8-hydroxyquinoline, or picolinic acid synthesize large amounts of magnesium protoporphyrin monomethyl ester and lesser amounts of magnesium protoporphyrin, protoporphyrin, and protochlorophyllide. Pigment formation proceeds in a linear manner for up to 21 hours after vacuum infiltration with 10 mm ?, ??-dipyridyl. Etiolated tissues of Zea mays L., Cucumis sativus L., and Pisum sativum L. respond in the same way to dipyridyl treatment. Compounds active in eliciting this response are aromatic heterocyclic nitrogenous bases which also act as bidentate chelators and form extremely stable complexes with iron; other metal ion chelators, such as ethylenediaminetetraacetic acid, salicylaldoxime, and sodium diethyldithiocarbamate, do not elicit any pigment synthesis. The ferrous, ferric, cobaltous, and zinc chelates of ?, ??-dipyridyl are similarly ineffective. If levulinic acid is supplied to etiolated bean leaves together with ?, ??-dipyridyl, porphyrin production is inhibited and ?-aminolevulinic acid accumulates in the tissue. Synthesis of porphyrins proceeds in the presence of 450 micrograms per milliliter chloramphenicol or 50 micrograms per milliliter cycloheximide with only partial diminution. We propose that heme or an iron-protein complex blocks the action of the enzyme(s) governing the synthesis of ?-aminolevulinic acid in etiolated leaves in the dark and that iron chelators antagonize this inhibition, leading to the biosynthesis of ?-aminolevulinic acid and porphyrins. PMID:16658677

Duggan, Jeffrey; Gassman, Merrill

1974-01-01

77

Ferrous Iron and Sulfur-Induced Genes in Sulfolobus metallicus  

Microsoft Academic Search

Genes of Sulfolobus metallicus that appeared to be upregulated in relation to growth on either ferrous iron or sulfur were identified using subtractive hybridization of cDNAs. The genes upregulated during growth on ferrous iron were found in a cluster, and most were predicted to encode membrane proteins. Quantitative reverse transcription-PCR of cDNA showed upregulation of most of these genes during

Stephan Bathe; Paul R. Norris

2007-01-01

78

Questions and Answers on Unapproved Chelation Products  

MedlinePLUS

... Administration (FDA) advises consumers to be wary of so-called “chelation” products that are marketed over-the-counter ( ... warning? The products affected by this warning include so-called “chelation” products that are marketed for home use ...

79

Natural chelating agents for radionuclide decorporation  

DOEpatents

This invention relates to the preparation of new, naturally produced chelating agents as well as to the method and resulting chelates of desorbing cultures in a bioavailable form involving Pseudomonas species or other microorganisms. A preferred microorganism is Pseudomonas aeruginosa which forms multiple chelates with thorium in the range of molecular weight 100-1,000 and also forms chelates with uranium of molecular weight in the area of 100-1,000 and 1,000-2,000.

Premuzic, Eugene T. (East Moriches, NY)

1988-01-01

80

Hydroxypyridonate and hydroxypyrimidinone chelating agents  

DOEpatents

The present invention provides hydroxypyridinone and hydroxypyrimidone chelating agents. Also provides are Gd(III) complexes of these agents, which are useful as contrast enhancing agents for magnetic resonance imaging. The invention also provides methods of preparing the compounds of the invention, as well as methods of using the compounds in magnetic resonance imaging applications.

Raymond, Kenneth N.; Doble, Daniel M.; Sunderland, Christopher J.; Thompson, Marlon

2005-01-25

81

Enhanced NO{sub x} removal in wet scrubbers using metal chelates. Final report, Volume 1  

SciTech Connect

Successful pilot plant tests of simultaneous removal of S0{sub 2} and NO{sub x} in a wet lime flue gas desulfurization system were concluded in December. The tests, at up to 1.5 MW(e) capacity, were conducted by the Cincinnati Gas and Electric Company and Dravo Lime Company for the US Department of Energy at a pilot facility at the Miami Fort station of CG&E near Cincinnati, Ohio. The pilot plant scrubbed a slipstream of flue gas from Unit 7, a 530 MW coal-fired electric generating unit. Tests were conducted in three phases between April and December. The technology tested was wet scrubbing with Thiosorbic{reg_sign} magnesium-enhanced lime for S0{sub 2} removal and simultaneous NO scrubbing with ferrous EDTA, a metal chelate. Magnesium-enhanced lime-based wet scrubbing is used at 20 full-scale high-sulfur coal-fired electric generating units with a combined capacity of 8500 NW. Ferrous EDTA reacts with nitric oxide, NO, which comprises about 95% of NO{sub x} from coal-fired boilers. In this report, although not precise, NO and NO{sub x} are used interchangably. A major objective of the tests was to combine NO{sub x} removal using ferrous EDTA, a developing technology, with SO{sub 2} removal using wet lime FGD, already in wide commercial use. If successful, this could allow wide application of this NO{sub x} removal technology.

Smith, K.; Lani, B.; Berisko, D.; Schultz, C.; Carlson, W. [Dravo Lime Co., Pittsburgh, PA (United States); Benson, L.B. [Radian Corp. (United States)

1992-12-01

82

Sensory evaluation of dairy supplements enriched with reduced iron, ferrous sulfate or ferrous fumarate.  

PubMed

Objective. To determine the degree of liking of the Oportunidades programme dietary supplements (DS) -purees and beverages- added with different iron salts (IS): reduced iron (RI), ferrous sulphate (FS) or ferrous fumarate (FF) during 24 weeks of storage. Materials and methods. The DS were evaluated through a hedonic scale for aroma, flavour and colour attributes; at time zero and every eight weeks, each panel member evaluated three DS with same flavour and presentation but different IS. Seventy women participated as panel members. Results. The chocolate and banana DS exhibited a change in preference by colour and flavour due to storage. DS with FS or RI showed the least preference by flavour and colour in the context of the three IS considered. The chocolate and neutral DS enriched with FS changed their colour and flavour. Conclusion. DS were, in general, well-liked; nonetheless, for purees enriched with FS and for beverages enriched with RI, the less-liked attributes were colour and flavour. PMID:25629275

Morales, Josefina C; Sánchez-Vargas, Elena; García-Zepeda, Rodrigo; Villalpando, Salvador

2015-02-01

83

Iron chelation and multiple sclerosis  

PubMed Central

Histochemical and MRI studies have demonstrated that MS (multiple sclerosis) patients have abnormal deposition of iron in both gray and white matter structures. Data is emerging indicating that this iron could partake in pathogenesis by various mechanisms, e.g., promoting the production of reactive oxygen species and enhancing the production of proinflammatory cytokines. Iron chelation therapy could be a viable strategy to block iron-related pathological events or it can confer cellular protection by stabilizing hypoxia inducible factor 1?, a transcription factor that normally responds to hypoxic conditions. Iron chelation has been shown to protect against disease progression and/or limit iron accumulation in some neurological disorders or their experimental models. Data from studies that administered a chelator to animals with experimental autoimmune encephalomyelitis, a model of MS, support the rationale for examining this treatment approach in MS. Preliminary clinical studies have been performed in MS patients using deferoxamine. Although some side effects were observed, the large majority of patients were able to tolerate the arduous administration regimen, i.e., 6–8 h of subcutaneous infusion, and all side effects resolved upon discontinuation of treatment. Importantly, these preliminary studies did not identify a disqualifying event for this experimental approach. More recently developed chelators, deferasirox and deferiprone, are more desirable for possible use in MS given their oral administration, and importantly, deferiprone can cross the blood–brain barrier. However, experiences from other conditions indicate that the potential for adverse events during chelation therapy necessitates close patient monitoring and a carefully considered administration regimen. PMID:24397846

Weigel, Kelsey J.; Lynch, Sharon G.; LeVine, Steven M.

2014-01-01

84

Luminescent lanthanide chelates and methods of use  

DOEpatents

The invention provides lanthanide chelates capable of intense luminescence. The celates comprise a lanthanide chelator covalently joined to a coumarin-like or quinolone-like sensitizer. Exemplary sensitzers include 2- or 4-quinolones, 2- or 4-coumarins, or derivatives thereof e.g. carbostyril 124 (7-amino-4-methyl-2-quinolone), coumarin 120 (7-amino-4-methyl-2-coumarin), coumarin 124 (7-amino-4-(trifluoromethyl)-2-coumarin), aminomethyltrimethylpsoralen, etc. The chelates form high affinity complexes with lanthanides, such as terbium or europium, through chelator groups, such as DTPA. The chelates may be coupled to a wide variety of compounds to create specific labels, probes, diagnostic and/or therapeutic reagents, etc. The chelates find particular use in resonance energy transfer between chelate-lanthanide complexes and another luminescent agent, often a fluorescent non-metal based resonance energy acceptor. The methods provide useful information about the structure, conformation, relative location and/or interactions of macromolecules.

Selvin, Paul R. (Berkeley, CA); Hearst, John (Berkeley, CA)

1997-01-01

85

Ferric and Possible Ferrous Sulfates in the Northern Mawrth Vallis Region of Mars  

NASA Astrophysics Data System (ADS)

Some CRISM scenes in the northern Mawrth Vallis region have patches, occurring on top of the Al phyllosilicate unit, with spectral features consistent with ferrous, or mixed ferric/ferrous, sulfate minerals indicating the action of acidic waters.

Farrand, W. H.; Glotch, T. D.; Horgan, B.

2014-07-01

86

76 FR 31357 - Agency Information Collection Activities: Comment Request for the Ferrous Metals Surveys  

Federal Register 2010, 2011, 2012, 2013, 2014

...Activities: Comment Request for the Ferrous Metals Surveys AGENCY: U.S. Geological Survey...paperwork requirements for the Ferrous Metals Surveys. This collection consists of...consumption data of 13 ores, concentrates, metals, and ferroalloys, some of which...

2011-05-31

87

40 CFR 464.30 - Applicability; description of the ferrous casting subcategory.  

Code of Federal Regulations, 2012 CFR

... Applicability; description of the ferrous casting subcategory. 464.30 Section 464.30...STANDARDS (CONTINUED) METAL MOLDING AND CASTING POINT SOURCE CATEGORY Ferrous Casting Subcategory § 464.30 Applicability;...

2012-07-01

88

40 CFR 464.30 - Applicability; description of the ferrous casting subcategory.  

Code of Federal Regulations, 2010 CFR

... Applicability; description of the ferrous casting subcategory. 464.30 Section 464.30...GUIDELINES AND STANDARDS METAL MOLDING AND CASTING POINT SOURCE CATEGORY Ferrous Casting Subcategory § 464.30 Applicability;...

2010-07-01

89

40 CFR 464.30 - Applicability; description of the ferrous casting subcategory.  

Code of Federal Regulations, 2011 CFR

... Applicability; description of the ferrous casting subcategory. 464.30 Section 464.30...GUIDELINES AND STANDARDS METAL MOLDING AND CASTING POINT SOURCE CATEGORY Ferrous Casting Subcategory § 464.30 Applicability;...

2011-07-01

90

40 CFR 464.30 - Applicability; description of the ferrous casting subcategory.  

Code of Federal Regulations, 2013 CFR

... Applicability; description of the ferrous casting subcategory. 464.30 Section 464.30...STANDARDS (CONTINUED) METAL MOLDING AND CASTING POINT SOURCE CATEGORY Ferrous Casting Subcategory § 464.30 Applicability;...

2013-07-01

91

40 CFR 464.30 - Applicability; description of the ferrous casting subcategory.  

Code of Federal Regulations, 2014 CFR

... Applicability; description of the ferrous casting subcategory. 464.30 Section 464.30...STANDARDS (CONTINUED) METAL MOLDING AND CASTING POINT SOURCE CATEGORY Ferrous Casting Subcategory § 464.30 Applicability;...

2014-07-01

92

Phosphonated chelates for nuclear imaging.  

PubMed

A series of bis-, tris- and tetra-phosphonated pyridine ligands is presented. In view of their potential use as chelates for radiopharmaceutical applications, the physico-chemical properties of the ligands and of their Co(II), Ni(II), Cu(II), and Zn(II) complexes were studied by means of potentiometry and UV-Vis absorption spectroscopy. The pKa values of the ligands and of the complexes, as well as the stability constants for the formation of the complexes, are presented. The kinetic aspects of the formation of Cu(II) complexes and of their dissociation in acidic media were studied by means of stopped flow experiments, and the stability of the Cu(II) complex toward reduction to Cu(I) was investigated by cyclic voltammetry and by titration with different reducing agents. The different thermodynamic and kinetic aspects of the polyphosphonated ligands were compared with regard to the impact of the number of phosphonic acid functions. Considering the very promising properties for complexation, preliminary SPECT/CT imaging experiments were carried out on mice with (99m)Tc using the bis- and tetra-phosphonated ligands L(2) and L(1). Finally, a bifunctional version of chelate L(1), L*, was used to label MTn12, a rat monoclonal antibody with both specificity and relatively high affinity for murine tenascin-C. The labeling was monitored by MALDI/MS spectrometry and the affinity of the labeled antibody was checked by immunostaining experiments. After chelation with (99m)Tc, the (99m)Tc-L*-MTn12 antibody was injected into a transgenic mouse with breast cancer and the biodistribution of the labeled antibody was followed by SPECT/CT imaging. PMID:25338628

Abada, Sabah; Lecointre, Alexandre; Christine, Câline; Ehret-Sabatier, Laurence; Saupe, Falk; Orend, Gertraud; Brasse, David; Ouadi, Ali; Hussenet, Thomas; Laquerrière, Patrice; Elhabiri, Mourad; Charbonnière, Loïc J

2014-12-21

93

DETERMINATION OF THE RATES AND PRODUCTS OF FERROUS IRON OXIDATION IN ARSENIC-CONTAMINATED POND WATER.  

EPA Science Inventory

Dissolved ferrous iron and arsenic in the presence of insufficient oxygenated ground water is released into a pond. When the mixing of ferrous iron and oxygenated water within the pond occurs, the ferrous iron is oxidized and precipitated as an iron oxide. Groups of experiments...

94

Ferrous iron-dependent drug delivery enables controlled and selective release of therapeutic  

E-print Network

Ferrous iron-dependent drug delivery enables controlled and selective release of therapeutic agents and cancer. Here, we describe a method to exploit aberrant levels of mobile ferrous iron (Fe parasites produce high concentrations of mobile ferrous iron as a consequence of their catabolism of host

Bogyo, Matthew

95

Orange but not apple juice enhances ferrous fumarate absorption in small children  

Technology Transfer Automated Retrieval System (TEKTRAN)

Ferrous fumarate is a common, inexpensive iron form increasingly used instead of ferrous sulfate as a food iron supplement. However, few data exist as to whether juices enhance iron absorption from ferrous fumarate. We studied 21 children, ages 4.0 to 7.9 years using a randomized crossover design. S...

96

Ferrous-iron induces lipid peroxidation with little damage to energy transduction in mitochondria  

Microsoft Academic Search

Addition of ferrous sulfate, but not ferric chloride, in micromolar concentrations to rat liver mitochondria induced high rates of consumption of oxygen. The oxygen consumed was several times in excess of the reducing capacity of ferrous-iron (O: Fe ratios 5–8). This occurred in the absence of NADPH or any exogenous oxidizable substrate. The reaction terminated on oxidation of ferrous ions.

Vidya Shivaswamy; C. K. Ramakrishna Kurup; T. Ramasarma

1993-01-01

97

LIMESTONE AND LIME NEUTRALIZATION OF FERROUS IRON ACID MINE DRAINAGE  

EPA Science Inventory

The U.S. Environmental Protection Agency conducted a 2-yr study on hydrated lime and rock-dust limestone neutralization of acid mine drainage containing ferrous iron at the EPA Crown Mine Drainage Control Field Site near Rivesville, West Virginia. The study investigated optimizat...

98

21 CFR 184.1307c - Ferrous citrate.  

Code of Federal Regulations, 2011 CFR

...citrate (iron (II) citrate, (C6 H6 FeO7 ), CAS Reg. No. 23383-11-1) is a slightly colored powder or white crystals. It is prepared from the reaction of sodium citrate with ferrous sulfate or by direct action of citric acid on iron...

2011-04-01

99

Final report on solid ferrous scrap copper removal  

SciTech Connect

Research has shown that physically distinct impurities in shredded ferrous scrap can be removed, and that metallic values can be recovered from the removed impurities. Although the closing of the U.S. Bureau of Mines terminated this research, it should be continued by others. Areas for continued research consideration could include further scrap testing to optimize process parameters, among others.

Hartman, A.D.; Williamson, C.A.; Davis. D.L.

1996-08-01

100

Preparation, characterization and the stability of ferrous glycinate nanoliposomes  

Microsoft Academic Search

Ferrous glycinate nanoliposomes prepared by the reverse-phase evaporation method (REV) from egg phosphatidylcholine (EPC) were investigated, based on the encapsulation efficiency, transmission electron microscopy (TEM), size distribution, and zeta potential. The nanoliposomes had high encapsulation efficiency, and TEM photomicrographs of nanoliposomes clearly showed their spherical shape. The size distribution and zeta potential indicated the stability of the nanoliposome suspensions. Retention

Baomiao Ding; Xiaoming Zhang; Khizar Hayat; Shuqin Xia; Chengsheng Jia; Mingyong Xie; Chengmei Liu

2011-01-01

101

46 CFR 56.60-3 - Ferrous materials.  

Code of Federal Regulations, 2010 CFR

...materials. (a) Ferrous pipe used for salt water service must be protected against corrosion...hotdip galvanizing or by the use of extra heavy schedule material. (b) (Reproduces...in welded construction, nor be shaped by oxygen-cutting process or other...

2010-10-01

102

Method for the preparation of ferrous low carbon porous material  

SciTech Connect

A method for preparing a porous metal article using a powder metallurgy forming process is provided which eliminates the conventional steps associated with removing residual carbon. The method uses a feedstock that includes a ferrous metal powder and a polycarbonate binder. The polycarbonate binder can be removed by thermal decomposition after the metal article is formed without leaving a carbon residue.

Miller, Curtis Jack

2014-05-27

103

Environmental biogeochemistry of chelating agents and recommendations for the disposal of chelated radioactive wastes  

Microsoft Academic Search

The environmental chemistry of the three most common aminopolycarboxylic acid chelating agents, NTA (nitrilotriacetic acid), EDTA (ethylenediaminetetraacetic acid), and DTPA (diethylenetriaminepentaacetic acid) is reviewed. This review includes information on their persistence in the environment, as well as their tendency to form complexes with actinides. Data on the sorption of chelated actinides by geologic substrates and on the uptake of chelated

J. L. Means; C. A. Alexander

1981-01-01

104

Beliefs about chelation among thalassemia patients  

PubMed Central

Background Understanding patients’ views about medication is crucial to maximize adherence. Thalassemia is a congenital blood disorder requiring chronic blood transfusions and daily iron chelation therapy. Methods The Beliefs in Medicine Questionnaire (BMQ) was used to assess beliefs in chelation in thalassemia patients from North America and London in the Thalassemia Longitudinal Cohort (TLC) of the Thalassemia Clinical Research Network (TCRN). Chelation adherence was based on patient report of doses administered out of those prescribed in the last four weeks. Results Of 371 patients (ages 5-58y, mean 24y), 93% were transfused and 92% receiving chelation (26% deferoxamine (DFO; a slow subcutaneous infusion via portable pump), 63% oral, 11% combination). Patients expressed high “necessity” for transfusion (96%), DFO chelation (92%) and oral chelation (89%), with lower “concern” about treatment (48%, 39%, 19% respectively). Concern about oral chelation was significantly lower than that of DFO (p<0.001). Self-reported adherence to chelation was not associated with views about necessity or concerns, but negatively correlated with perceived sensitivity to DFO (Sensitive Soma scale; r=?0.23, p=0.01) and side effects of oral chelation (r=?0.14, p=0.04). High ferritin iron levels, potentially indicating lower adherence, were found in 41% of patients reporting low necessity of oral chelation compared to 24% reporting high necessity (p=0.048). Concerns about treatment were associated with lower quality of life and more symptoms of anxiety and depression. Conclusions Despite their requirement for multimodal therapy, thalassemia patients have positive views about medicine, more so than in other disease populations. Patients may benefit from education about the tolerability of chelation and strategies to effectively cope with side effects, both of which might be beneficial in lowering body iron burden. Clinicaltrials.gov identifier NCT00661804 PMID:23216870

2012-01-01

105

Absorption of Iron from Ferritin Is Independent of Heme Iron and Ferrous Salts in Women and Rat Intestinal Segments123  

PubMed Central

Ferritin iron from food is readily bioavailable to humans and has the potential for treating iron deficiency. Whether ferritin iron absorption is mechanistically different from iron absorption from small iron complexes/salts remains controversial. Here, we studied iron absorption (RBC 59Fe) from radiolabeled ferritin iron (0.5 mg) in healthy women with or without non-ferritin iron competitors, ferrous sulfate, or hemoglobin. A 9-fold excess of non-ferritin iron competitor had no significant effect on ferritin iron absorption. Larger amounts of iron (50 mg and a 99-fold excess of either competitor) inhibited iron absorption. To measure transport rates of iron that was absorbed inside ferritin, rat intestinal segments ex vivo were perfused with radiolabeled ferritin and compared to perfusion with ferric nitrilotriacetic (Fe-NTA), a well-studied form of chelated iron. Intestinal transport of iron absorbed inside exogenous ferritin was 14.8% of the rate measured for iron absorbed from chelated iron. In the steady state, endogenous enterocyte ferritin contained >90% of the iron absorbed from Fe-NTA or ferritin. We found that ferritin is a slow release source of iron, readily available to humans or animals, based on RBC iron incorporation. Ferritin iron is absorbed by a different mechanism than iron salts/chelates or heme iron. Recognition of a second, nonheme iron absorption process, ferritin endocytosis, emphasizes the need for more mechanistic studies on ferritin iron absorption and highlights the potential of ferritin present in foods such as legumes to contribute to solutions for global iron deficiency. PMID:22259191

Chen, Huijun; Miranda, Constanza; Janser, Heinz; Elsenhans, Bernd; Núñez, Marco T.; Pizarro, Fernando; Schümann, Klaus

2012-01-01

106

Vivapure Metal Chelate Mini spin columns  

E-print Network

® Vivapure Metal Chelate Mini spin columns Hisn #12;E. coli cell lysates containing a recombinant to a SDS-PAGE and stained with CoomassieTM Blue. M = Molecular weight marker Lane 1: E. coli cell lysate Hisn-tagged protein were purified using Vivapure Metal Chelate Mini spin columns and competitor

Lebendiker, Mario

107

Iron Chelation Therapy in Myelodysplastic Syndromes  

PubMed Central

Myelodysplastic syndromes (MDS) are a heterogeneous disorder of the hematopoietic stem cells, frequently characterized by anemia and transfusion dependency. In low-risk patients, transfusion dependency can be long lasting, leading to iron overload. Iron chelation therapy may be a therapeutic option for these patients, especially since the approval of oral iron chelators, which are easier to use and better accepted by the patients. The usefulness of iron chelation in MDS patients is still under debate, mainly because of the lack of solid prospective clinical trials that should take place in the future. This review aims to summarize what is currently known about the incidence and clinical consequences of iron overload in MDS patients and the state-of the-art of iron chelation therapy in this setting. We also give an overview of clinical guidelines for chelation in MDS published to date and some perspectives for the future. PMID:20672005

Messa, Emanuela; Cilloni, Daniela; Saglio, Giuseppe

2010-01-01

108

Induction of porphyrin synthesis in etiolated bean leaves by chelators of iron.  

PubMed

Primary leaves of 7- to 9-day-old etiolated seedlings of Phaseolus vulgaris L. var. Red Kidney infiltrated in darkness with aqueous solutions of alpha, alpha'-dipyridyl, o-phenanthroline, pyridine-2-aldoxime, pyridine-2-aldehyde, 8-hydroxyquinoline, or picolinic acid synthesize large amounts of magnesium protoporphyrin monomethyl ester and lesser amounts of magnesium protoporphyrin, protoporphyrin, and protochlorophyllide. Pigment formation proceeds in a linear manner for up to 21 hours after vacuum infiltration with 10 mm alpha, alpha'-dipyridyl. Etiolated tissues of Zea mays L., Cucumis sativus L., and Pisum sativum L. respond in the same way to dipyridyl treatment. Compounds active in eliciting this response are aromatic heterocyclic nitrogenous bases which also act as bidentate chelators and form extremely stable complexes with iron; other metal ion chelators, such as ethylenediaminetetraacetic acid, salicylaldoxime, and sodium diethyldithiocarbamate, do not elicit any pigment synthesis. The ferrous, ferric, cobaltous, and zinc chelates of alpha, alpha'-dipyridyl are similarly ineffective. If levulinic acid is supplied to etiolated bean leaves together with alpha, alpha'-dipyridyl, porphyrin production is inhibited and delta-aminolevulinic acid accumulates in the tissue. Synthesis of porphyrins proceeds in the presence of 450 micrograms per milliliter chloramphenicol or 50 micrograms per milliliter cycloheximide with only partial diminution. We propose that heme or an iron-protein complex blocks the action of the enzyme(s) governing the synthesis of delta-aminolevulinic acid in etiolated leaves in the dark and that iron chelators antagonize this inhibition, leading to the biosynthesis of delta-aminolevulinic acid and porphyrins. PMID:16658677

Duggan, J; Gassman, M

1974-02-01

109

Chelation therapy in nickel poisoning.  

PubMed

For the treatment of acute poisoning from the inhalation of nickel carbonyl, sodium diethyldithiocarbamate (Dithiocarb) has proved to be a specific antidote; tetraethylthiuram (Antabuse) is effective to a lesser degree; d-penicillamine and dimercaprol (BAL) have limited therapeutic value. For the treatment of nickel eczema and dermatitis, favorable response has been obtained by placing patients on a diet of low nickel content together with the oral administration of Dithiocarb or Antabuse. No specific therapy has been advanced for the treatment of nickel cancer in humans. In experimental animals, Dithiocarb has an inhibitory effect on the production of rat rhabdomyosarcomas induced by the intramuscular implantation of nickel subsulfide, and N-methyl formamide inhibits the growth of transplantable nickel fibromas in rats. It is suggested that for the treatment of tumors arising from the implantations of nickel-containing prostheses in humans, chelation therapy be considered. PMID:6260008

Sunderman, F W

1981-01-01

110

Enhanced NO{sub x} removal in wet scrubbers using metal chelates. Final report, Volume 2  

SciTech Connect

Successful pilot plant tests of simultaneous removal of SO{sub 2} and NO{sub x} in a wet lime flue gas desulfurization system were concluded in December. The test, at up to 1.5 MW(e) capacity, were conducted by the Cincinnati Gas and Electric Company and Dravo Lime Company for the US Department of Energy at a pilot plant facility at the Miami Fort station of CG&E near Cincinnati, Ohio. The pilot plant scrubbed a slipstream of flue gas from Unit 7 a 530 MW coal-fired electric generating unit. Tests were conducted in three phases between April and December. The technology tested was wet scrubbing with Thiosorbic{reg_sign} magnesium-enhanced lime for SO{sub 2} removal and simultaneous NO scrubbing with ferrous EDTA, a metal chelate. Magnesium-enhanced lime-based wet scrubbing is used at 20 full-scale high-sulfur coal-fired electric generating units with a combined capacity of 8500 MW. Ferrous EDTA reacts with nitric oxide, NO, which comprises about 96% of NO{sub x} from coal-fired boilers. In this report, although not precise, NO and NO{sub x} are used interchangeably. A major objective of the tests was to combine NO{sub x} removal using ferrous EDTA, a developing technology, with SO{sub 2} removal using wet lime FGD, already in wide commercial use. If successful, this could allow wide application of this NO{sub x} removal technology. Volume 2 covers: description and results of NO{sub x} removal tests; and description and results of waste characterization studies.

NONE

1992-12-01

111

Natural chelating agents for radionuclide decorporation  

DOEpatents

This invention relates to the production of metal-binding compounds useful for the therapy of heavy metal poisoning, for biological mining and for decorporation of radionuclides. The present invention deals with an orderly and effective method of producing new therapeutically effective chelating agents. This method uses challenge biosynthesis for the production of chelating agents that are specific for a particular metal. In this approach, the desired chelating agents are prepared from microorganisms challenged by the metal that the chelating agent is designed to detoxify. This challenge induces the formation of specific or highly selective chelating agents. The present invention involves the use of the challenge biosynthetic method to produce new complexing/chelating agents that are therapeutically useful to detoxify uranium, plutonium, thorium and other toxic metals. The Pseudomonas aeruginosa family of organisms is the referred family of microorganisms to be used in the present invention to produce the new chelating agent because this family is known to elaborate strains resistant to toxic metals.

Premuzic, E.T.

1985-06-11

112

A cost function of Greek non-ferrous metal industry  

Microsoft Academic Search

A translog cost function in the form of a third-order series Taylor expansion was used for the estimation of cost in the Greek non-ferrous metal industry which is based on an annual time series for the period 1969–1990 concerning: the price of production factors, the production volume, and the total cost of production. The estimated cost function permit us to

K. D. Tsekouras; N. G. Zagouras

1998-01-01

113

Microbial Reduction of Ferrous Arsenate: Biogeochemical Implications for Arsenic Mobilization  

SciTech Connect

In reduced aqueous environments, the presence of As in solution is a function of both biotic and abiotic mechanisms. Recent studies have demonstrated a significant release of As(III) through the microbial reduction of dissolved and mineral-bound As(V), which raises health concerns when the greater comparative mobility and toxicity of As(III) is considered. These release mechanisms do not operate in isolation but occur in concert with a number of removal processes, including secondary mineralization and sorption to other natural substrates. Thermodynamic and applied experimental studies have shown that ferrous arsenates, such as symplesite [Fe(II){sub 3}(As(V)O{sub 4}){sub 2} {center_dot} 8H{sub 2}O], may provide a significant sink for Fe(II) and As(V). In this study, the stability of a representative ferrous arsenate phase in the presence of the arsenate-reducing bacterium Shewanella sp. strain ANA-3 is examined. The reduction of ferrous arsenate by ANA-3 results in the release of aqueous As(III) and, subsequently, the progressive nucleation of a biogenic ferrous arsenite phase proximal to the microbial cells. The valence states of secondary solid-phase products were verified using X-ray absorption spectroscopy (XAS). Electron microscopy reveals that nucleation occurs on cellular exudates which may imply a role of extracellular reduction through c-type cytochromes as investigated in recent literature. These observations provide new insights into the reduction mechanisms of ANA-3 and the biogeochemical cycling of As(III) in natural systems.

Babechuk, M.; Weisener, C.G.; Fryer, B.; Paktunc, D.; Maunders, C.; (Windsor); (CCM); (McMaster U.)

2010-11-12

114

Stabilized ferrous gluconate as iron source for food fortification  

Microsoft Academic Search

The iron bioavailability and acute oral toxicity in rats of a ferrous gluconate compound stabilized with glycine (SFG), designed\\u000a for food fortification, was studied in this work by means of the prophylactic method and the Wilcoxon method, respectively. For the former studies, SFG was homogenously added to a basal diet of low iron\\u000a content, reaching a final iron concentration of

Alexis E. Lysionek; Marcela B. Zubillaga; María J. Salgueiro; Ricardo A. Caro; Natalia M. Leonardi; Eduardo Ettlin; José R. Boccio

2003-01-01

115

Hydrometallurgical recovery of non-ferrous metals from secondary sources  

SciTech Connect

Recycling of fine oxidized particles of non-ferrous metals usually cannot be carried out by pyrometallurgical methods. Hydrometallurgy provides an alternative technology to reintroduce the resulting products as secondary raw materials into the industrial cycle, thereby saving resources and energy while keeping the environment a little cleaner. The paper summarizes the methods employed by Hydrometal to achieve these objectives and stigmatizes the latest counterproductive international regulations which create ever more obstacles to environmentally sound recycling.

Goldschmidt, J. [Jean Goldschmidt International SA, Brussels (Belgium); [Hydrometal SA, Brussels (Belgium)

1995-12-31

116

Chromate removal from aqueous wastes by reduction with ferrous ion  

Microsoft Academic Search

Experimental measurements of reaction stoichiometries indicate that optimum conditions for chromate removal from oxygenated, 25°C aqueous wastes by reduction with ferrous ion occur at pH less than 10.0 in solutions containing the following anions: ClOâ⁻, Cl⁻, F⁻, NOâ⁻, and POâ\\/sup 3 -\\/. At pH greater than 10.0 and at lower pH in solutions that contain greater than 10⁻⁴ M total

L. E. Eary; Dhanpat Rai

1988-01-01

117

Ferrous Iron Is a Significant Component of Bioavailable Iron in Cystic Fibrosis Airways  

PubMed Central

ABSTRACT Chronic, biofilm-like infections by the opportunistic pathogen Pseudomonas aeruginosa are a major cause of mortality in cystic fibrosis (CF) patients. While much is known about P. aeruginosa from laboratory studies, far less is understood about what it experiences in vivo. Iron is an important environmental parameter thought to play a central role in the development and maintenance of P. aeruginosa infections, for both anabolic and signaling purposes. Previous studies have focused on ferric iron [Fe(III)] as a target for antimicrobial therapies; however, here we show that ferrous iron [Fe(II)] is abundant in the CF lung (~39 µM on average for severely sick patients) and significantly correlates with disease severity (? = ?0.56, P = 0.004), whereas ferric iron does not (? = ?0.28, P = 0.179). Expression of the P. aeruginosa genes bqsRS, whose transcription is upregulated in response to Fe(II), was high in the majority of patients tested, suggesting that increased Fe(II) is bioavailable to the infectious bacterial population. Because limiting Fe(III) acquisition inhibits biofilm formation by P. aeruginosa in various oxic in vitro systems, we also tested whether interfering with Fe(II) acquisition would improve biofilm control under anoxic conditions; concurrent sequestration of both iron oxidation states resulted in a 58% reduction in biofilm accumulation and 28% increase in biofilm dissolution, a significant improvement over Fe(III) chelation treatment alone. This study demonstrates that the chemistry of infected host environments coevolves with the microbial community as infections progress, which should be considered in the design of effective treatment strategies at different stages of disease. PMID:23963183

Hunter, Ryan C.; Asfour, Fadi; Dingemans, Jozef; Osuna, Brenda L.; Samad, Tahoura; Malfroot, Anne; Cornelis, Pierre; Newman, Dianne K.

2013-01-01

118

Chelation in root canal therapy reconsidered.  

PubMed

The aim of this study was to assess interactions of EDTA and citric acid (CA) with sodium hypochlorite (NaOCl), the indispensable endodontic irrigant. Other chelators were simultaneously evaluated as possible alternatives: sodium triphosphate (STP), amino tris methylenephosphonic acid (ATMA), and 1- hydroxyethylidene-1, 1-bisphosphonate (HEBP). Available chlorine was titrated in chelator-NaOCl solutions. All chelators other than HEBP and STP caused an almost complete, immediate loss of available chlorine in solution. Atomic absorbtion spectrometry and SEM evaluation of root canal walls of instrumented teeth indicated that NaOCl had no negative effect on calcium-complexing ability of chelators. STP was too weak a complexing agent to warrant further studies. Finally, CA-, EDTA-, and HEBP-NaOCl mixtures were evaluated for their antimicrobial capacity. Again, EDTA and CA negatively interfered with NaOCl, while HEBP did not. PMID:16249726

Zehnder, Matthias; Schmidlin, Patrick; Sener, Beatrice; Waltimo, Tuomas

2005-11-01

119

Fluid extraction using carbon dioxide and organophosphorus chelating agents  

DOEpatents

Methods for extracting metalloid and metal species from a solid or liquid material by exposing the material to a fluid solvent, particularly supercritical CO.sub.2, and a chelating agent are described. The chelating agent forms a chelate with the species, the chelate being soluble in the fluid to allow removal of the species from the material. In preferred embodiments the extraction solvent is supercritical CO.sub.2 and the chelating agent comprises an organophosphorous chelating agent, particularly sulfur-containing organophosphorous chelating agents, including mixtures of chelating agents. Examples of chelating agents include monothiophosphinic acid, di-thiophosphinic acid, phosphine sulfite, phosphorothioic acid, and mixtures thereof. The method provides an environmentally benign process for removing metal and metalloids from industrial waste solutions, particularly acidic solutions. Both the chelate and the supercritical fluid can be regenerated and the contaminant species recovered to provide an economic, efficient process.

Smart, Neil G. (Moscow, ID); Wai, Chien M. (Moscow, ID); Lin, Yuehe (Moscow, ID); Kwang, Yak Hwa (Moscow, ID)

1998-01-01

120

Fluid extraction using carbon dioxide and organophosphorus chelating agents  

DOEpatents

Methods for extracting metalloid and metal species from a solid or liquid material by exposing the material to a fluid solvent, particularly supercritical CO{sub 2}, and a chelating agent are described. The chelating agent forms a chelate with the species, the chelate being soluble in the fluid to allow removal of the species from the material. In preferred embodiments the extraction solvent is supercritical CO{sub 2} and the chelating agent comprises an organophosphorous chelating agent, particularly sulfur-containing organophosphorous chelating agents, including mixtures of chelating agents. Examples of chelating agents include monothiophosphinic acid, di-thiophosphinic acid, phosphine sulfite, phosphorothioic acid, and mixtures thereof. The method provides an environmentally benign process for removing metal and metalloids from industrial waste solutions, particularly acidic solutions. Both the chelate and the supercritical fluid can be regenerated and the contaminant species recovered to provide an economic, efficient process. 1 fig.

Smart, N.G.; Wai, C.M.; Lin, Y.; Kwang, Y.H.

1998-11-24

121

Inhibitory effect of iron-oxidizing bacteria on ferrous-promoted chalcopyrite leaching  

PubMed

It is generally accepted that iron-oxidizing bacteria, Thiobacillus ferrooxidans, enhance chalcopyrite leaching. However, this article details a case of the bacteria suppressing chalcopyrite leaching. Bacterial leaching experiments were performed with sulfuric acid solutions containing 0 or 0.04 mol/dm3 ferrous sulfate. Without ferrous sulfate, the bacteria enhance copper extraction and oxidation of ferrous ions released from chalcopyrite. However, the bacteria suppressed chalcopyrite leaching when ferrous sulfate was added. This is mainly due to the bacterial consumption of ferrous ions which act as a promoter for chalcopyrite oxidation with dissolved oxygen. Coprecipitation of copper ions with jarosite formed by the bacterial ferrous oxidation also causes the bacterial suppression of copper extraction. Copyright 1999 John Wiley & Sons, Inc. PMID:10397886

Hiroyoshi; Hirota; Hirajima; Tsunekawa

1999-08-20

122

Microbial oxidation of ferrous iron in acid mine water at sulfur and iron-sulfide mine  

Microsoft Academic Search

The microbial oxidation of ferrous iron in the acid mine water from the abandoned Matsuo sulfur and iron-sulfide mine area was investigated. The acid mine water had an extremely low pH value and contained a high concentration of ferrous iron (about 1,000 ppm). The ferrous iron was oxidized rapidly to the ferric form in the acid mine water. The oxidation

Norio Wakao; Yonekichi Sakurai; Hideo Shiota

1977-01-01

123

Overview of Lightweight Ferrous Materials: Strategies and Promises  

NASA Astrophysics Data System (ADS)

Reducing the density of steels is a novel approach for weight reduction of automobiles to improve fuel efficiency. In this overview article, strategies for the development of lightweight steels are presented with a focus on bulk ferrous alloys. The metallurgical principles of these steels and their mechanical properties of relevance to automotive applications are discussed. Some of the engineering aspects highlighting the possible problems related to mass production of these steels are also considered. Application prospects of these steels vis-à-vis standard automotive steels are shown.

Rana, Radhakanta; Lahaye, Chris; Ray, Ranjit Kumar

2014-08-01

124

Overview of Lightweight Ferrous Materials: Strategies and Promises  

NASA Astrophysics Data System (ADS)

Reducing the density of steels is a novel approach for weight reduction of automobiles to improve fuel efficiency. In this overview article, strategies for the development of lightweight steels are presented with a focus on bulk ferrous alloys. The metallurgical principles of these steels and their mechanical properties of relevance to automotive applications are discussed. Some of the engineering aspects highlighting the possible problems related to mass production of these steels are also considered. Application prospects of these steels vis-à-vis standard automotive steels are shown.

Rana, Radhakanta; Lahaye, Chris; Ray, Ranjit Kumar

2014-09-01

125

Substructures of the (252) ferrous martensite and their crystallographic significance  

SciTech Connect

Many ferrous martensites have been found to possess a macroscopically invariant habit plane close to (252){sub f} and to exhibit complex and variable substructures that cannot be not only satisfactorily explained but also fully characterized so far. The present work attempts to examine the mechanism of occurrence of the complex substructures and their correlation to other crystallographic properties, esp. to the shape strain, on the basis of a new theory. The theory describes the atomic movements in the lattice change represented with the Bain distortion in the past.

Wang Shidao [Lanzhou Railway Inst. (China). Dept. of Mechanical Engineering] [Lanzhou Railway Inst. (China). Dept. of Mechanical Engineering; [Chinese Academy of Sciences, Shenyang (China). Lab. of Atomic Imaging of Solids; Hei Zukun [Dalian Maritime Univ. (China). Research Inst. of Materials Technology] [Dalian Maritime Univ. (China). Research Inst. of Materials Technology

1999-04-23

126

Iron-chelation therapy with oral chelators in patients with thalassemia major.  

PubMed

In thalassemia major (TM), without iron chelation therapy, iron-mediated free radical damage causes liver, endocrine, and myocardial toxicities. Deferoxamine has universally been the standard therapeutic option for iron chelation therapy; however, its usage is troublesome, leading to suboptimal patient compliance. In order to maximize the effectiveness of iron chelation therapy, oral iron chelators deferiprone and deferasirox constitute an important development, offering a potential to improve compliance. Although both oral drugs are effective, they have differences including different pharmacokinetics and side-effect profiles. Our retrospective evaluation of TM patients using oral chelators showed that oral chelators are effective in reducing iron overload regarding ferritin level and partially in cardiac T2* value. However, in our study side effects and discontinuation rates were unexpectedly high and close follow-up of TM patients using oral chelators should be carefully done. The variability in rate of side effects and drug discontinuation in spelenectomized patients using oral chelators suggests that spleen may have a role in pharmacokinetics of these drugs, as well. PMID:23321010

Uygun, Vedat; Kurtoglu, Erdal

2013-01-01

127

Iron (FeII) Chelation, Ferric Reducing Antioxidant Power, and Immune Modulating Potential of Arisaema jacquemontii (Himalayan Cobra Lily)  

PubMed Central

This study explored the antioxidant and immunomodulatory potential of ethnomedicinally valuable species, namely, Arisaema jacquemontii of north-western Himalayan region. The tubers, leaves, and fruits of this plant were subjected to extraction using different solvents. In vitro antioxidant studies were performed in terms of chelation power on ferrous ions and FRAP assay. The crude methanol extract of leaves was found to harbour better chelating capacity (58% at 100??g/mL) and reducing power (FRAP value 1085.4 ± 0.11??MFe3+/g dry wt.) than all the other extracts. The crude methanol extract was thus further partitioned with solvents to yield five fractions. Antioxidant study of fractions suggested that the methanol fraction possessed significant chelation capacity (49.7% at 100??g/mL) and reducing power with FRAP value of 1435.4??M/g dry wt. The fractions were also studied for immune modulating potential where it was observed that hexane fraction had significant suppressive effect on mitogen induced T-cell and B-cell proliferation and remarkable stimulating effect on humoral response by 141% and on DTH response by 168% in immune suppressed mice as compared to the controls. Therefore, it can be concluded that A. jacquemontii leaves hold considerable antioxidant and immunomodulating potential and they can be explored further for the identification of their chemical composition for a better understanding of their biological activities. PMID:24895548

Sudan, Rasleen; Bhagat, Madhulika; Singh, Jasvinder; Koul, Anupurna

2014-01-01

128

Analyzing the International Exergy Flow Network of Ferrous Metal Ores  

PubMed Central

This paper employs an un-weighted and weighted exergy network to study the properties of ferrous metal ores in countries worldwide and their evolution from 2002 to 2012. We find that there are few countries controlling most of the ferrous metal ore exports in terms of exergy and that the entire exergy flow network is becoming more heterogeneous though the addition of new nodes. The increasing of the average clustering coefficient indicates that the formation of an international exergy flow system and regional integration is improving. When we contrast the average out strength of exergy and the average out strength of currency, we find both similarities and differences. Prices are affected largely by human factors; thus, the growth rate of the average out strength of currency has fluctuated acutely in the eleven years from 2002 to 2012. Exergy is defined as the maximum work that can be extracted from a system and can reflect the true cost in the world, and this parameter fluctuates much less. Performing an analysis based on the two aspects of exergy and currency, we find that the network is becoming uneven. PMID:25188407

Qi, Hai; An, Haizhong; Hao, Xiaoqing; Zhong, Weiqiong; Zhang, Yanbing

2014-01-01

129

Wear study of carbide reinforced P/M ferrous composites  

SciTech Connect

Ferrous alloys have been used for decades as wear resistant materials for applications where severe wear (primarily abrasion) has been a problem. Irons and steels have an advantage in these applications because they can be alloyed with various elements to create structures which are quite harder than the iron matrix. For example, martensitic matrices can be developed as well as carbide structures (consisting usually of Cr-, Nb- or V-based carbides or some other complex carbide structure). However, these materials are usually made through melt/solidification techniques which can sometimes limit the type, volume fraction, and morphology of the carbide. In P/M processing these factors can be ignored in most instances. This paper will discuss the abrasive and impact-abrasive wear behavior of one class of wear resistant materials based on TiC. The materials removal mechanisms will be discussed with emphasis on microstructure-wear interactions. The results will be compared to traditional wear resistant ferrous based alloys.

Hawk, Jeffrey A.; Dogan, Omer N.; Wilson, Rick D.

2000-10-01

130

Method and apparatus for back-extracting metal chelates  

DOEpatents

A method is described for extracting metal and metalloid species from a solid or liquid substrate using a supercritical fluid solvent containing one or more chelating agents followed by back-extracting the metal and metalloid species from the metal and metalloid chelates formed thereby. The back-extraction acidic solution is performed utilizing an acidic solution. Upon sufficient exposure of the metal and metalloid chelates to the acidic solution, the metal and metalloid species are released from the chelates into the acid solution, while the chelating agent remains in the supercritical fluid solvent. The chelating agent is thereby regenerated and the metal and metalloid species recovered. 3 figs.

Wai, C.M.; Smart, N.G.; Lin, Y.

1998-08-11

131

Method and apparatus for back-extracting metal chelates  

DOEpatents

A method of extracting metal and metalloid species from a solid or liquid substrate using a supercritical fluid solvent containing one or more chelating agents followed by back-extracting the metal and metalloid species from the metal and metalloid chelates formed thereby. The back-extraction acidic solution is performed utilizing an acidic solution. Upon sufficient exposure of the metal and metalloid chelates to the acidic solution, the metal and metalloid species are released from the chelates into the acid solution, while the chelating agent remains in the supercritical fluid solvent. The chelating agent is thereby regenerated and the metal and metalloid species recovered.

Wai, Chien M. (Moscow, IA); Smart, Neil G. (Moscow, IA); Lin, Yuehe (Moscow, IA)

1998-01-01

132

Clean ferrous casting technology research. Final technical report, September 29, 1993--December 31, 1995  

SciTech Connect

This report details results of a 30-month program to develop methods of making clean ferrous castings, i.e., castings free of inclusions and surface defects. The program was divided into 3 tasks: techniques for producing clean steel castings, electromagnetic removal of inclusions from ferrous melts, and study of causes of metal penetration in sand molds in cast iron.

Piwonka, T.S. [ed.

1996-01-01

133

Ferrous Ferric Chloride Induces the Differentiation of Cultured Mouse Epidermal Melanocytes Additionally with Herbal Medicines  

Microsoft Academic Search

Ferrous ferric chloride (FFC) is a special form of aqueous iron that is a complex of ferrous chloride and ferric chloride and participates in oxidation and reduction reactions. My previous study showed that FFC stimulated the proliferation and differentiation of cultured epidermal melanoblasts or melanocytes derived from newborn mice. However, it is not known whether FFC stimulates the proliferation and

Tomohisa Hirobe

2009-01-01

134

Trial of ferrous glycine sulphate in the fortification of common salt with iron  

Microsoft Academic Search

Ferrous glycine sulphate, an organic complex of glycine and ferrous sulphate, was tested as a source of iron to produce iron fortified salt. The dry mixing was found superior to the spray mixing technique. The fortified salt retained the colour of common salt. The iron distribution was uniform, approximately 1000 ± 50 ppm. The iron stability of the fortified salt

S. Ranganathan; K. Vasantha Lakshmi; Vinodini Reddy

1996-01-01

135

Trypanotoxic activity of thiosemicarbazone iron chelators.  

PubMed

Only a few drugs are available for treating sleeping sickness and nagana disease; parasitic infections caused by protozoans of the genus Trypanosoma in sub-Saharan Africa. There is an urgent need for the development of new medicines for chemotherapy of these devastating diseases. In this study, three newly designed thiosemicarbazone iron chelators, TSC24, Dp44mT and 3-AP, were tested for in vitro activity against bloodstream forms of Trypanosoma brucei and human leukaemia HL-60 cells. In addition to their iron chelating properties, TSC24 and Dp44mT inhibit topoisomerase II? while 3-AP inactivates ribonucleotide reductase. All three compounds exhibited anti-trypanosomal activity, with minimum inhibitory concentration (MIC) values ranging between 1 and 100?µM and 50% growth inhibition (GI50) values of around 250?nM. Although the compounds did not kill HL-60 cells (MIC values >100?µM), TSC24 and Dp44mT displayed considerable cytotoxicity based on their GI50 values. Iron supplementation partly reversed the trypanotoxic and cytotoxic activity of TSC24 and Dp44mT but not of 3-AP. This finding suggests possible synergy between the iron chelating and topoisomerase II? inhibiting activity of the compounds. However, further investigation using separate agents, the iron chelator deferoxamine and the topoisomerase II inhibitor epirubicin, did not support any synergy for the interaction of iron chelation and topoisomerase II inhibition. Furthermore, TSC24 was shown to induce DNA degradation in bloodstream forms of T. brucei indicating that the mechanism of trypanotoxic activity of the compound is topoisomerase II independent. In conclusion, the data support further investigation of thiosemicarbazone iron chelators with dual activity as lead compounds for anti-trypanosomal drug development. PMID:25595343

Ellis, Samuel; Sexton, Darren W; Steverding, Dietmar

2015-03-01

136

A macrocyclic chelator with unprecedented Th?? affinity.  

PubMed

A novel macrocyclic octadentate ligand incorporating terephthalamide binding units has been synthesized and evaluated for the chelation of Th(4+). The thorium complex was structurally characterized by X-ray diffraction and in solution with kinetic studies and spectrophotometric titrations. Dye displacement kinetic studies show that the ligand is a much more rapid chelator of Th(4+) than prevailing ligands (1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid and diethylenetriaminepentaacetic acid). Furthermore, the resulting complex was found to have a remarkably high thermodynamic stability, with a formation constant of 10(54). These data support potential radiotherapeutic applications. PMID:24870296

Pham, Tiffany A; Xu, Jide; Raymond, Kenneth N

2014-06-25

137

Ferrous versus Ferric Oral Iron Formulations for the Treatment of Iron Deficiency: A Clinical Overview  

PubMed Central

Iron deficiency anaemia represents a major public health problem, particularly in infants, young children, pregnant women, and females with heavy menses. Oral iron supplementation is a cheap, safe, and effective means of increasing haemoglobin levels and restoring iron stores to prevent and correct iron deficiency. Many preparations are available, varying widely in dosage, formulation (quick or prolonged release), and chemical state (ferrous or ferric form). The debate over the advantages of ferrous versus ferric formulations is ongoing. In this literature review, the tolerability and efficacy of ferrous versus ferric iron formulations are evaluated. We focused on studies comparing ferrous sulphate preparations with ferric iron polymaltose complex preparations, the two predominant forms of iron used. Current data show that slow-release ferrous sulphate preparations remain the established and standard treatment of iron deficiency, irrespective of the indication, given their good bioavailability, efficacy, and acceptable tolerability demonstrated in several large clinical studies. PMID:22654638

Santiago, Palacios

2012-01-01

138

Ferrous versus ferric oral iron formulations for the treatment of iron deficiency: a clinical overview.  

PubMed

Iron deficiency anaemia represents a major public health problem, particularly in infants, young children, pregnant women, and females with heavy menses. Oral iron supplementation is a cheap, safe, and effective means of increasing haemoglobin levels and restoring iron stores to prevent and correct iron deficiency. Many preparations are available, varying widely in dosage, formulation (quick or prolonged release), and chemical state (ferrous or ferric form). The debate over the advantages of ferrous versus ferric formulations is ongoing. In this literature review, the tolerability and efficacy of ferrous versus ferric iron formulations are evaluated. We focused on studies comparing ferrous sulphate preparations with ferric iron polymaltose complex preparations, the two predominant forms of iron used. Current data show that slow-release ferrous sulphate preparations remain the established and standard treatment of iron deficiency, irrespective of the indication, given their good bioavailability, efficacy, and acceptable tolerability demonstrated in several large clinical studies. PMID:22654638

Santiago, Palacios

2012-01-01

139

Oxidation of ferrous ions by ozone in acidic solutions  

SciTech Connect

In the aqueous phase of the atmosphere (aerosols, clouds, fog, etc.), where iron, acids, and ozone are simultaneously present, the oxidation of Fe{sup 2+} by O{sub 3} is very important as an ozone sink. The oxidation of ferrous ions by ozone in acidic solution of pH 0-2 was studied using a stopped-flow spectrophotometer. The reaction can be characterized as an oxygen atom transfer from O{sub 3} to Fe{sup 2+}. An intermediate product assigned to be the ferryl ion, FeO{sup 2+}, was found and its UV-vis spectrum measured. A reaction mechanism is proposed, which accounts for all the authors experimental results.

Loegager, T.; Holcman, J.; Sehested, K.; Pedersen, T. (RISOE National Lab., Roskilde (Denmark))

1992-08-19

140

Development of an upconverting chelate assay  

NASA Astrophysics Data System (ADS)

We report progress on performing a cell-based assay for the detection of EGFR on cell surfaces by using upconverting chelates. An upconversion microscope has been developed for performing assays and testing optical response. A431 cells are labeled with europium DOTA and imaged using this upconverting microscope.

Xiao, Xudong; Haushalter, Jeanne P.; Kotz, Kenneth T.; Faris, Gregory W.

2005-04-01

141

CHELATING ABILITY OF PROCTOLIN TETRAZOLE ANALOGUE  

Technology Transfer Automated Retrieval System (TEKTRAN)

The aim of the investigation was to establish a chelating ability of a new proctolin analog of the sequence Arg-Tyr-Leu-psi-[CN4]Ala-Thr towards copper(II) ions. The insertion of the tetrazole moiety into the peptide sequence considerably has changed the coordination ability of the ligand. Potentiom...

142

Chelated Indium Activable Tracers for Geothermal Reservoirs  

E-print Network

SGP-TR-99 Chelated Indium Activable Tracers for Geothermal Reservoirs Constantinos V. Indium was se1ecti:d to be the most promising activable tracer. The thermal stability of indium tracer of the soluble indium concentration was made as a f'unction of time by neutron activation analysis. From the data

Stanford University

143

Bacterial oxidation of ferrous iron at low temperatures.  

PubMed

This study comprises the first report of ferrous iron oxidation by psychrotolerant, acidophilic iron-oxidizing bacteria capable of growing at 5 degrees C. Samples of mine drainage-impacted surface soils and sediments from the Norilsk mining region (Taimyr, Siberia) and Kristineberg (Skellefte district, Sweden) were inoculated into acidic ferrous sulfate media and incubated at 5 degrees C. Iron oxidation was preceded by an approximately 3-month lag period that was reduced in subsequent cultures. Three enrichment cultures were chosen for further work and one culture designated as isolate SS3 was purified by colony isolation from a Norilsk enrichment culture for determining the kinetics of iron oxidation. The 16S rRNA based phylogeny of SS3 and two other psychrotolerant cultures, SS5 from Norilsk and SK5 from Northern Sweden, was determined. Comparative analysis of amplified 16S rRNA gene sequences showed that the psychrotolerant cultures aligned within Acidithiobacillus ferrooxidans. The rate constant of iron oxidation by growing cultures of SS3 was in the range of 0.0162-0.0104 h(-1) depending on the initial pH. The oxidation kinetics followed an exponential pattern, consistent with a first order rate expression. Parallel iron oxidation by a mesophilic reference culture of Acidithiobacillus ferrooxidans was extremely slow and linear. Precipitates harvested from the 5 degrees C culture were identified by X-ray diffraction as mixtures of schwertmannite (ideal formula Fe(8)O(8)(OH)(6)SO(4)) and jarosite (KFe(3)(SO(4))(2)(OH)(6)). Jarosite was much more dominant in precipitates produced at 30 degrees C. PMID:17304566

Kupka, Daniel; Rzhepishevska, Olena I; Dopson, Mark; Lindström, E Börje; Karnachuk, Olia V; Tuovinen, Olli H

2007-08-15

144

Chelation therapy after the Trial to Assess Chelation Therapy: results of a unique trial  

PubMed Central

Purpose of review EDTA chelation therapy has been in off-label use for the treatment of atherosclerosis. We review the results of the first large-scale randomized trial of this treatment. Recent findings The trial to assess chelation therapy was a $30 million National Institutes of Health-funded study of the safety and efficacy of EDTA-based chelation infusions in 1708 post-myocardial infarction (MI) patients. The trial to assess chelation therapy demonstrated a significant (P?=?0.035) 18% reduction in a combined primary endpoint of death, MI, stroke, coronary revascularization, or hospitalization for angina. In diabetic patients the benefit was more extreme, with a 41% relative reduction in risk (P?=?0.0002) and a 43% reduction in total mortality (P?=?0.011). Safety data were favorable. A reduction of oxidative stress by chelation of toxic metals has been proposed as a possible mechanism of action. Summary Recent research suggests that EDTA chelation may be a well-tolerated and effective treatment for post-MI patients. Future replication and mechanistic studies are important prior to implementation in all post-MI patients. PMID:25023079

Avila, Maria D.; Escolar, Esteban; Lamas, Gervasio A.

2014-01-01

145

Effects of iron polymaltose complex, ferrous fumarate and ferrous sulfate treatments in anemic pregnant rats, their fetuses and placentas.  

PubMed

Although oral iron preparations are widely prescribed to prevent and to treat iron deficiency anemia in pregnancy, comparative data on their effects to the mother, fetus and placenta are limited. In this study, the effects of oral iron polymaltose complex (IPC), ferrous fumarate (FF) and ferrous sulfate (FS) were compared in anemic pregnant rats, their fetuses and placentas. Hematological variables and oxidative stress markers in the liver, heart and kidneys of the dams and fetuses as well as the markers for oxidative stress, inflammation and hypoxia in placentas were assessed. Pregnancy outcome was measured by number of fetuses, and by neonate and placental weight. All therapies were comparably effective in correcting anemia. FS and FF, but not IPC, resulted in liver damage in dams and oxidative stress in dams, fetuses and placentas. FS group presented the highest catalase and GPx levels in dams, fetuses and placentas. IPC, but not FF or FS, restored normal TNF-? and IL6 expression levels in placentas whereas FS-treated animals presented the highest cytokine levels, suggesting a local inflammatory reaction. Anemia-induced high levels of HIF-1? were partially lowered by IPC and FF but further elevated by FS. Most of the negative effects associated with IDA were resolved by IPC treatment. Especially FS treatment was found to elicit hepatic damage in the dams, oxidative stress in the dams, fetuses and placenta as well as inflammation and high levels of HIF-1? in the placenta. Pregnancy outcome of FFand FS-treated animals was worse than that of IPC-treated animals. PMID:23547731

Toblli, Jorge E; Cao, Gabriel; Oliveri, Leda; Angerosa, Margarita

2013-06-01

146

Methyl tert-butyl ether (MTBE) degradation by ferrous ion-activated persulfate oxidation: feasibility and kinetics studies.  

PubMed

The objective of this study was to evaluate the feasibility of using ferrous ion-activated persulfate oxidation to remediate groundwater contaminated with methyl tert-butyl ether (MTBE). In this study, batch experiments were conducted to evaluate the effects of various factors on the efficiency of MTBE degradation including persulfate concentrations, ferrous ion concentrations, and persulfate coupled with hydrogen peroxide. Results show that ferrous ion-activated persulfate oxidation was capable of degrading MTBE efficiently. Persulfate and ferrous ion concentrations correlated with MTBE degradation rates. However, excess addition of ferrous ion resulted in decreased MTBE degrading rates most likely because of competition for sulfate free radicals between ferrous ion and MTBE. Two main byproducts of MTBE degradation, tert-butyl formate and tert-butyl alcohol, were detected in the experiments; both were, however, subsequently degraded. Results of sulfate analysis show that proper addition of ferrous ion could prevent unnecessary persulfate decomposition. PMID:19691249

Chen, K F; Kao, C M; Wu, L C; Surampalli, R Y; Liang, S H

2009-07-01

147

Small electric furnaces for producing thermal insulating materials and ferrous alloys  

Microsoft Academic Search

The design principles and the technical and working characteristics are presented for a series of ovens of capacity 250–500\\u000a kVA, which are intended for producing basalt wool and ferrous alloys.

I. M. Bershitskii; A. A. Skochilov; N. P. Belyakova; V. M. Korovina; R. R. Avedin; S. B. Mirskii

2007-01-01

148

Enumeration and Detection of Anaerobic Ferrous Iron Oxidizing, Nitrate-Reducing Bacteria from Diverse European Sediments  

Microsoft Academic Search

Anaerobic, nitrate-dependent microbial oxidation of ferrous iron was recently recognized as a new type of metabolism. In order to study the occurrence of three novel groups of ferrous iron-oxidizing, nitrate-reducing bacteria (represented by strains BrG1, BrG2, and BrG3), 16S rRNA-targeted oligonucleotide probes were developed. In pure-culture experiments, these probes were shown to be suitable for fluorescent in situ hybrid- ization,

KRISTINA L. STRAUB; BERIT E. E. BUCHHOLZ-CLEVEN

1998-01-01

149

The effect of ferrous sulphate and sucralfate on the bioavailability of oral gemifloxacin in healthy volunteers.  

PubMed

Sucralfate is a cytoprotectant with antacid properties and ferrous sulphate is commonly prescribed for iron-deficiency anaemia. This open, randomized, single-dose, five-way crossover study investigated the effect of sucralfate and ferrous sulphate on the bioavailability of gemifloxacin, a novel fluoroquinolone antimicrobial. Twenty-seven healthy male volunteers received gemifloxacin, 320 mg p.o., alone, 3 h after sucralfate (2 g) or ferrous sulphate (325 mg), or 2 h before sucralfate or ferrous sulphate. Each subject received all five dosing regimens in random order with at least 6 days between regimens. Plasma samples collected up to 48 h after dosing with gemifloxacin, were assayed for gemifloxacin to determine pharmacokinetic parameters. Administration of gemifloxacin 3 h after sucralfate produced a marked decrease of 53% in the area under the plasma concentration-time curve from time zero extrapolated to infinity (AUC0-infinity), and a decrease of 69% in the maximal plasma concentration (Cmax). Administration of gemifloxacin 3 h after ferrous sulphate resulted in only a modest reduction of 11% in AUC0-infinity and of 20% in Cmax, which was not considered to be clinically significant. In contrast, at the doses used neither sucralfate nor ferrous sulphate altered gemifloxacin bioavailability when it was administered 2 h before either of these agents. Gemifloxacin was well tolerated in all the regimens. The results of this study support the dosing recommendation that gemifloxacin can be safely administered at least 2 h before sucralfate or ferrous sulphate, or at least 3 h after ferrous sulphate. PMID:10929878

Allen, A; Bygate, E; Faessel, H; Isaac, L; Lewis, A

2000-08-01

150

Influence of ferrous iron incorporation on the structure of hydroxyapatite.  

PubMed

Iron is a vital element of cellular function within the body. High concentrations of iron can be found in the kidneys and the circulatory system. In bones and teeth it is present as a trace element. The use of iron-based compounds in combination with hydroxyapatite offers a new alternative for prosthetic devices. This work investigates the synthesis and processing of iron containing apatites as a possible new type of ceramic for biomedical devices. Stoichiometric and calcium deficient iron containing apatites were synthesized by a wet chemical reaction with di-ammonium-hydrogen-phosphate, calcium nitrate and a ferrous iron nitrate solution. A secondary phase of tri-calcium-phosphate (TCP) was observed after heat treatment of iron containing, calcium deficient, hydroxyapatite. The apatite structure was maintained after heat treatment of stoichiometric apatite, synthesized in the presence of iron. Sintering in air produced oxidation of Fe2+ to Fe3+, resulting in the formation of hematite as a secondary phase. The introduction of iron into the synthesis of hydroxyapatite causes: (i) an increase of the a-lattice parameter after synthesis and heat treatment in air; (ii) an increase in the c-lattice parameter after sintering in air. PMID:15875246

Morrissey, R; Rodríguez-Lorenzo, L M; Gross, K A

2005-05-01

151

Friction and wear of some ferrous-base metallic glasses  

NASA Technical Reports Server (NTRS)

Sliding friction experiments, X-ray photoelectron spectroscopy (XPS) analysis, and electron microscopy and diffraction studies were conducted with ferrous base metallic glasses (amorphous alloys) in contact with aluminum oxide at temperatures to 750 C in a vacuum. Sliding friction experiments were also conducted in argon and air atmospheres. The results of the investigation indicate that the coefficient of friction increases with increasing temperature to 350 C in vacuum. The increase in friction is due to an increase in adhesion resulting from surface segregation of boric oxide and/or silicon oxide to the surface of the foil. Above 500 C the coefficient of friction decreased rapidly. The decrease correlates with the segregation of boron nitride to the surface. Contaminants can come from the bulk of the material to the surface upon heating and impart boric oxide and/or silicon oxide at 350 C and boron nitride above 500 C. The segregation of contaminants is responsible for the friction behavior. The amorphous alloys have superior wear resistance to crystalline 304 stainless steel. The relative concentrations of the various constituents at the surfaces of the amorphous alloys are very different from the nominal bulk compositions.

Miyoshi, K.; Buckley, D. H.

1983-01-01

152

Characterization of the ferrous iron uptake system of Escherichia coli.  

PubMed Central

Escherichia coli has an iron(II) transport system (feo) which may make an important contribution to the iron supply of the cell under anaerobic conditions. Cloning and sequencing of the iron(II) transport genes revealed an open reading frame (feoA) possibly coding for a small protein with 75 amino acids and a membrane protein with 773 amino acids (feoB). The upstream region of feoAB contained a binding site for the regulatory protein Fur, which acts with iron(II) as a corepressor in all known iron transport systems of E. coli. In addition, a Fnr binding site was identified in the promoter region. The FeoB protein had an apparent molecular mass of 70 kDa in sodium dodecyl sulfate-polyacrylamide gel electrophoresis and was localized in the cytoplasmic membrane. The sequence revealed regions of homology to ATPases, which indicates that ferrous iron uptake may be ATP driven. FeoA or FeoB mutants could be complemented by clones with the feoA or feoB gene, respectively. Images PMID:8407793

Kammler, M; Schön, C; Hantke, K

1993-01-01

153

Effect of ferrous metal presence on lead leaching in municipal waste incineration bottom ashes.  

PubMed

The recovery of ferrous and non-ferrous metals from waste to energy (WTE) ash continues to advance as the sale of removed metals improves the economics of waste combustion. Published literature suggests that Fe and Fe oxides play a role in suppressing Pb leaching in the Toxicity Characteristic Leaching Procedure (TCLP); further removal of ferrous metals from WTE ashes may facilitate higher Pb leaching under the TCLP. Eight WTE bottom ash size-fractions, from three facilities, were evaluated to assess the effect of metallic Fe addition and ferrous metal removal on TCLP leaching. Metallic Fe addition was demonstrated to reduce Pb leaching; the removal of ferrous metals by magnet resulted in a decrease in total available Pb (mg/kg) in most ash samples, yet Pb leachability increased in 5 of 6 ash samples. The research points to two chemical mechanisms to explain these results: redox interactions between Pb and Fe and the sorption of soluble Pb onto Fe oxide surfaces, as well as the effect of the leachate pH before and after metals recovery. The findings presented here indicate that generators, processors, and regulators of ash should be aware of the impact ferrous metal removal may have on Pb leaching, as a substantial increase in leaching may have significant implications regarding the management of WTE ashes. PMID:25464288

Oehmig, Wesley N; Roessler, Justin G; Zhang, Jianye; Townsend, Timothy G

2015-02-11

154

Anaerobic oxidation of ferrous iron by purple bacteria, a new type of phototrophic metabolism.  

PubMed Central

Anoxic iron-rich sediment samples that had been stored in the light showed development of brown, rusty patches. Subcultures in defined mineral media with ferrous iron (10 mmol/liter, mostly precipitated as FeCO3) yielded enrichments of anoxygenic phototrophic bacteria which used ferrous iron as the sole electron donor for photosynthesis. Two different types of purple bacteria, represented by strains L7 and SW2, were isolated which oxidized colorless ferrous iron under anoxic conditions in the light to brown ferric iron. Strain L7 had rod-shaped, nonmotile cells (1.3 by 2 to 3 microns) which frequently formed gas vesicles. In addition to ferrous iron, strain L7 used H2 + CO2, acetate, pyruvate, and glucose as substrate for phototrophic growth. Strain SW2 had small rod-shaped, nonmotile cells (0.5 by 1 to 1.5 microns). Besides ferrous iron, strain SW2 utilized H2 + CO2, monocarboxylic acids, glucose, and fructose. Neither strain utilized free sulfide; however, both strains grew on black ferrous sulfide (FeS) which was converted to ferric iron and sulfate. Strains L7 and SW2 grown photoheterotrophically without ferrous iron were purple to brownish red and yellowish brown, respectively; absorption spectra revealed peaks characteristic of bacteriochlorophyll a. The closest phototrophic relatives of strains L7 and SW2 so far examined on the basis of 16S rRNA sequences were species of the genera Chromatium (gamma subclass of proteobacteria) and Rhodobacter (alpha subclass), respectively. In mineral medium, the new isolates formed 7.6 g of cell dry mass per mol of Fe(II) oxidized, which is in good agreement with a photoautotrophic utilization of ferrous iron as electron donor for CO2 fixation. Dependence of ferrous iron oxidation on light and CO2 was also demonstrated in dense cell suspensions. In media containing both ferrous iron and an organic substrate (e.g., acetate, glucose), strain L7 utilized ferrous iron and the organic compound simultaneously; in contrast, strain SW2 started to oxidize ferrous iron only after consumption of the organic electron donor. Ferrous iron oxidation by anoxygenic phototrophs is understandable in terms of energetics. In contrast to the Fe3+/Fe2+ pair (E0 = +0.77 V) existing in acidic solutions, the relevant redox pair at pH 7 in bicarbonate-containing environments, Fe(OH)3 + HCO3-/FeCO3, has an E0' of +0.2 V. Ferrous iron at pH 7 can therefore donate electrons to the photosystem of anoxygenic phototrophs, which in purple bacteria has a midpoint potential around +0.45 V. The existence of ferrous iron-oxidizing anoxygenic phototrophs may offer an explanation for the deposition of early banded-iron formations in an assumed anoxic biosphere in Archean times. Images PMID:7811087

Ehrenreich, A; Widdel, F

1994-01-01

155

Degradation of ciprofloxacin and sulfamethoxazole by ferrous-activated persulfate: implications for remediation of groundwater contaminated by antibiotics.  

PubMed

The wide occurrence of antibiotics in groundwater raised great scientific interest as well as public awareness in recent years due to their potential ability to spread antibiotic resistant gene and pose risk to humans. The present study investigated the ferrous ion (Fe(II)) activated decomposition of persulfate (S2O8(2-)), as a potential in situ chemical oxidation (ISCO) approach, for remediation of groundwater contaminated by antibiotics. Fe(II)-persulfate mediated ciprofloxacin (CIP) degradation was found to be more efficient than sulfamethoxazole (SMX) at near neutral pH (pH6.0), probably due to the higher electric density in CIP molecule and its ability to form complex with Fe(II) as a ligand. Hydroxyl (HO) and sulfate radical (SO4(-)) were determined to be responsible for the degradation of CIP and SMX in Fe(II)-persulfate system by molecular probes. No enhancement in the degradation of CIP was observed when citrate (CA), ethylenediaminetetraacetate (EDTA) and (S,S)-ethylenediamine-N,N'-disuccinate (EDDS) were used as Fe(II) chelating agents in Fe(II)-persulfate system. For SMX, CA and EDTA accelerated the degradation by Fe(II)-persulfate. Degradation of antibiotics in river water matrix was nearly the same as that in Milli-Q water, implying the possibility of using Fe(II)-persulfate for antibiotics depletion under environmentally relevant condition. A comparison of the degradation efficiency of SMX with other sulfonamides and sulfanilic acid indicated that the heterocyclic ring has a large impact on the degradation of sulfonamides. Transformation products of CIP and SMX by Fe(II)-persulfate were analyzed by solid phase extraction-liquid chromatography-mass spectrometry (SPE-LC-MS) technique. Based on the intermediate products, Fe(II)-persulfate mediated CIP degradation pathways were tentatively proposed. PMID:24342085

Ji, Yuefei; Ferronato, Corinne; Salvador, Arnaud; Yang, Xi; Chovelon, Jean-Marc

2014-02-15

156

Chelators whose affinity for calcium is decreased by illumination  

NASA Technical Reports Server (NTRS)

The present invention discloses a group of calcium chelating compounds which have a descreased affinity for calcium following illumination. These new compounds contain a photolabile nitrobenzyl derivative coupled to a tetracarboxylate Ca.sup.2+ chelating parent compound having the octacoordinate chelating groups characteristic of EGTA or BAPTA. In a first form, the new compounds are comprised of a BAPTA-like chelator coupled to a single 2-nitrobenzyl derivative, which in turn is a photochemical precursor of a 2-nitrosobenzophenone. In a second form, the new compounds are comprised of a BAPTA-like chelator coupled to two 2-nitrobenzyl derivatives, themselves photochemical prcursors of the related 2-nitrosobenzophenones. The present invention also discloses a novel method for preparing 1-hydroxy- or 1-alkoxy-1-(2-nitroaryl)-1-aryl methanes. Methanes of this type are critical to the preparation of, or actually constitute, the photolabile Ca.sup.2+ chelating compounds disclosed and claimed herein.

Tsien, Roger Y. (Inventor); Grynkiewicz, Grzegorz (Inventor); Minta, Akwasi (Inventor)

1987-01-01

157

Ultrafine Particulate Ferrous Iron and Anthracene Associations with Mitochondrial Dysfunction  

SciTech Connect

The ultrafine size fraction of ambient particles (ultrafine particles, UFP, diameter < 100 nm) has been identified as being far more potent in their adverse health effects than their larger counterparts, yet, the detailed mechanisms for why UFP display such distinctive toxicity are not well understood. In the present study, ambient UFP were exposed to mitochondria while monitoring electron transport chain (ETC) activity as a model system for biochemical toxicity. UFP samples were collected in rural (Ellensburg, WA) and urban environments (Seattle, WA) and chemically characterized for total trace metals, ferrous (Fe(II)) and easily reducible ferric (Fe(III)) iron, polycyclic aromatic hydrocarbons, and surface constituents with X-ray photoelectron spectroscopy (XPS). Low doses of UFP (8 µg mL-1) caused a decrease in mitochondrial ETC function compared to controls in 94% of the samples after The 20 min of exposure. Significant correlations exist between initial %ETC inhibition (0-10 min) and Fe(II) (R=0.55, P=0.03, N=15), anthracene (R=0.74, P<0.01, N=13), and %C-O surface bonds (R=0.56, P=0.03, N=15), whereby anthracene and %C-O correlate as well (R=0.58, P=0.03, N=14). No significant associations were identified with total Fe and other trace metals. Results from this study indicate that the redox active fraction of Fe as well as the abundance of anthracene-related, C-O containing, surface structures may contribute to the initial detrimental behavior of UFP, thus supporting the idea that the Fe(II)/Fe(III) and certain efficient hydroquinone/quinone redox pairs may play an important role likely due to their potential to produce reactive oxygen species (ROS).

Faiola, Celia; Johansen, Anne M.; Rybka, Sara; Nieber, Annika; Thomas-Bradley, Carin; Bryner, Stephanie; Johnston, Justin M.; Engelhard, Mark H.; Nachimuthu, Ponnusamy; Owens, Kalyn S.

2011-04-20

158

Metal regeneration of iron chelates in nitric oxide scrubbing  

DOEpatents

The present invention relates to a process of using metal particles to reduce NO to NH.sub.3. More specifically, the invention concerns an improved process to regenerate iron (II) (CHELATE) by reduction of iron (II) (CHELATE) (NO) complex, which process comprises: a) contacting an aqueous solution containing iron (II) (CHELATE) (NO) with metal particles at between about 20.degree. and 90.degree. C. to reduce NO present, produce ammonia or an ammonium ion, and produce free iron (II) (CHELATE) at a pH of between about 3 and 8. The process is useful to remove NO from flue gas and reduce pollution.

Chang, Shih-Ger (El Cerrito, CA); Littlejohn, David (Oakland, CA); Shi, Yao (Berkeley, CA)

1997-08-19

159

Metal regeneration of iron chelates in nitric oxide scrubbing  

DOEpatents

The present invention relates to a process of using metal particles to reduce NO to NH{sub 3}. More specifically, the invention concerns an improved process to regenerate iron (II) (CHELATE) by reduction of iron (II) (CHELATE) (NO) complex, which process comprises: (a) contacting an aqueous solution containing iron (II) (CHELATE) (NO) with metal particles at between about 20 and 90 C to reduce NO present, produce ammonia or an ammonium ion, and produce free iron (II) (CHELATE) at a pH of between about 3 and 8. The process is useful to remove NO from flue gas and reduce pollution. 34 figs.

Chang, S.G.; Littlejohn, D.; Shi, Y.

1997-08-19

160

Evaluation of Ferric and Ferrous Iron Therapies in Women with Iron Deficiency Anaemia  

PubMed Central

Introduction. Different ferric and ferrous iron preparations can be used as oral iron supplements. Our aim was to compare the effects of oral ferric and ferrous iron therapies in women with iron deficiency anaemia. Methods. The present study included 104 women diagnosed with iron deficiency anaemia after evaluation. In the evaluations performed to detect the aetiology underlying the iron deficiency anaemia, it was found and treated. After the detection of the iron deficiency anaemia aetiology and treatment of the underlying aetiology, the ferric group consisted of 30 patients treated with oral ferric protein succinylate tablets (2 × 40?mg elemental iron/day), and the second group consisted of 34 patients treated with oral ferrous glycine sulphate tablets (2 × 40?mg elemental iron/day) for three months. In all patients, the following laboratory evaluations were performed before beginning treatment and after treatment. Results. The mean haemoglobin and haematocrit increases were 0.95?g/dL and 2.62% in the ferric group, while they were 2.25?g/dL and 5.91% in the ferrous group, respectively. A significant difference was found between the groups regarding the increase in haemoglobin and haematocrit values (P < 0.05). Conclusion. Data are submitted on the good tolerability, higher efficacy, and lower cost of the ferrous preparation used in our study. PMID:25006339

Berber, Ilhami; Erkurt, Mehmet Ali; Aydogdu, Ismet; Kuku, Irfan

2014-01-01

161

Reusable chelating resins concentrate metal ions from highly dilute solutions  

NASA Technical Reports Server (NTRS)

Column chromatographic method uses new metal chelating resins for recovering heavy-metal ions from highly dilute solutions. The absorbed heavy-metal cations may be removed from the chelating resins by acid or base washes. The resins are reusable after the washes are completed.

Bauman, A. J.; Weetal, H. H.; Weliky, N.

1966-01-01

162

Chelation Treatment for Autism Spectrum Disorders: A Systematic Review  

ERIC Educational Resources Information Center

Chelation treatment is used to eliminate specific metals from the body, such as mercury. It has been hypothesized that mercury poisoning may be a factor in autism and data suggest that perhaps 7% of individuals with autism spectrum disorder (ASD) have received chelation treatment. It would therefore seem timely to review studies investigating the…

Davis, Tonya N.; O'Reilly, Mark; Kang, Soyeon; Lang, Russell; Rispoli, Mandy; Sigafoos, Jeff; Lancioni, Giulio; Copeland, Daelynn; Attai, Shanna; Mulloy, Austin

2013-01-01

163

Lead chelation to immobilised Symphytum officinale L. (comfrey) root tannins  

Microsoft Academic Search

Reported correlations between tannin level and metal accumulation within plant tissues suggest that metal-chelating tannins may help plants to tolerate toxic levels of heavy metal contaminants. This paper supports such correlations using a new method that demonstrated the ability of plant tannins to chelate heavy metals, and showed that the relative levels of tannins in tissues were quantitatively related to

Lily Chin; David W. M. Leung; H. Harry Taylor

2009-01-01

164

Heavy metal displacement in chelate-irrigated soil during phytoremediation  

Microsoft Academic Search

Heavy metals in wastewater sewage sludge (biosolids), applied to land, contaminate soils. Phytoremediation, the use of plants to clean up toxic heavy metals, might remove them. Chelating agents are added to soil to solubilize the metals for enhanced phytoextraction. Yet no studies follow the displacement and leaching of heavy metals in soil with and without roots following solubilization with chelates.

M. S Liphadzi; M. B Kirkham

2003-01-01

165

Clawing Back: Broadening the Notion of Metal Chelators in Medicine  

PubMed Central

The traditional notion of chelation therapy is the administration of a chemical agent to remove metals from the body. But formation of a metal-chelate can have biological ramifications that are much broader than metal elimination. Exploring these other possibilities could lead to pharmacological interventions that alter the concentration, distribution, or reactivity of metals in targeted ways for therapeutic benefit. This review highlights recent examples that showcase four general strategies of using principles of metal chelation in medicinal contexts beyond the traditional notion of chelation therapy. These strategies include altering metal biodistribution, inhibiting specific metalloenzymes associated with disease, enhancing the reactivity of a metal complex to promote cytotoxicity, and conversely, passivating the reactivity of metals by site-activated chelation to prevent cytotoxicity. PMID:23332666

Franz, Katherine J.

2013-01-01

166

Chelation of cadmium by combining deferasirox and deferiprone in rats.  

PubMed

The present research aimed to characterize the potential efficiency of two chelators after cadmium administration for 60 days following two dose levels of 20 and 40 mg/kg body weight daily to male rats. However, the hypothesis that the two chelators might be more efficient as combined therapy than as single therapy in removing cadmium from the body was considered. In this way, two known chelators deferasirox and deferiprone (L(1)) were chosen and tested in the acute rat model. Two chelators were given orally as a single or combined therapy for the period of a week. Cadmium and iron concentrations in various tissues were determined by graphite furnace and flame atomic absorption spectrometry methods, respectively. The combined chelation therapy results show that Deferasirox and L(1) are able to remove cadmium ions from the body while iron concentration returned to the normal level and symptoms are also decreased. PMID:21245204

Jamilaldin Fatemi, S; Saljooghi, Amir Shokooh; Balooch, Faezeh Dahooee; Iranmanesh, Marzieh; Golbafan, Mohammad Reza

2011-05-01

167

Chelators for copper radionuclides in positron emission tomography radiopharmaceuticals†  

PubMed Central

The development of chelating agents for copper radionuclides in positron emission tomography radiopharmaceuticals has been a highly active and important area of study in recent years. The rapid evolution of chelators has resulted in highly specific copper chelators that can be readily conjugated to biomolecules and efficiently radiolabeled to form stable complexes in vivo. Chelators are not only designed for conjugation to monovalent biomolecules but also for incorporation into multivalent targeting ligands such as theranostic nanoparticles. These advancements have strengthened the role of copper radionuclides in the fields of nuclear medicine and molecular imaging. This review emphasizes developments of new copper chelators that have most greatly advanced the field of copper-based radiopharmaceuticals over the past 5 years. PMID:24347474

Cai, Zhengxin; Anderson, Carolyn J.

2014-01-01

168

Ferrous sulfate versus iron polymaltose complex for treatment of iron deficiency anemia in children.  

PubMed

We assessed the clinical response and side effects of Ferrous sulfate (FS) and Iron polymaltose complex (IPC) in 118 children with Iron deficiency anemia (IDA). Subjects were randomized to receive therapy with either oral IPC (Group A, n=59) or oral FS (Group B, n=59); all were given elemental iron in three divided doses of 6 mg/kg/day. One hundred and six children could be followed up; 53 in each group. Children who received ferrous sulfate were having higher hemoglobin level, and less residual complaints as compared to those who had received iron polymaltose complex. Our study suggests ferrous sulfate has a better clinical response and less significant adverse effects during treatment of IDA in children. PMID:19430060

Bopche, Ankur Vikas; Dwivedi, Rashmi; Mishra, Rakesh; Patel, G S

2009-10-01

169

Removal of phosphorus from wastewaters using ferrous salts - a pilot scale membrane bioreactor study.  

PubMed

A pilot scale membrane bioreactor (3.7 m(3)/day capacity), configured for alternate point ferrous sulphate addition, was evaluated in a fourteen month trial to comply with an effluent discharge requirement of less than 0.15 mg-P/L at the 50(th) percentile and less than 0.30 mg-P/L at the 90th percentile. Ferrous sulphate was added at a molar ratio (Fe(II):PO4) of 2.99 in the filtration chamber for 85 days and 2.60 in the primary anoxic zone for 111 days. Addition of ferrous salts to the anoxic zone achieved a final effluent phosphorous concentration (mg-P/L) of <0.05 (29%), <0.15 (77%) and <0.30 (95%), while addition of ferrous salts in the filtration zone achieved <0.05 (18%), <0.15 (63%) and <0.30 (95%). Analysis of the concentration of iron(II) in the supernatant indicated that phosphorus was mainly removed via adsorption to amorphous iron oxyhydroxides particles in both dosing scenarios. However, analysis of residence time distribution (RTD) data of the reactor indicated that severe short-circuiting from the dosing point to the membrane outlet could occur when the ferrous salts were added to the membrane zone while the reactor behaved close to a completely mixed reactor when dosing to the primary anoxic zone, resulting in improved phosphorus removal. The addition of ferrous salt was also found to delay the onset of severe increase in trans-membrane pressure as a result of the removal of macro-molecules. However, detailed analysis of the form and concentration of iron species in the supernatant and permeate indicated that the presence of fine iron particles resulted in a higher fouling rate when Fe(II) was added to the membrane zone rather than the primary anoxic zone and could cause more severe irreversible fouling in long-term operation. PMID:24709534

Wang, Yuan; Tng, K Han; Wu, Hao; Leslie, Greg; Waite, T David

2014-06-15

170

Chelation in metal intoxication XXI: chelation in lead intoxication during vitamin B complex deficiency  

SciTech Connect

The vitamin B-complex deficiency increases the vulnerability to neuro- and systemic toxicity of Pb in young rats. Thus, the nutritional status of vitamins like that of protein or minerals seems to influence the etiology of Pb toxicity and may be expected to affect the response toward Pb chelators. 2,3 dimercaptosuccinic acid (DMSA) and N-(2-hydroxyethyl) ethylene-diamine triacetic acid (HEDTA) have been found to be effective antidotes to Pb intoxication. In the present study, these selective metal chelating agents were compared for their ability to reduce the body burden of Pb and restore the altered biochemical parameters in young developing Pb intoxicated rats maintained on normal or vitamin B-complex deficient diet. The investigation was aimed to suggest suitable prophylaxis of Pb poisoning prevalent among children who may also be suffering from vitamin deficiency in developing and poor countries.

Not Available

1986-09-01

171

A rapid, simple questionnaire to assess gastrointestinal symptoms after oral ferrous sulphate supplementation  

PubMed Central

Background Oral iron supplementation is often associated with rapid onset of gastrointestinal side-effects. The aim of this study was to develop and trial a short, simple questionnaire to capture these early side-effects and to determine which symptoms are more discriminating. Methods The study was a double-blind placebo-controlled randomized parallel trial with one week treatment followed by one week wash-out. Subjects were randomized into two treatment groups (n?=?10/group) to receive either ferrous sulphate (200 mg capsules containing 65 mg of iron) or placebo, both to be taken at mealtimes twice daily during the treatment period. Subjects completed the questionnaires daily for 14 days. The questionnaire included gastrointestinal symptoms commonly reported to be associated with the oral intake of ferrous iron salts (i.e. nausea, vomiting, heartburn, abdominal pain, diarrhoea, and constipation). Results Seventy five per cent of participants reporting the presence of one or more symptoms in the first week of the study were in the ferrous sulphate group. In the second week of the study (i.e. wash-out), 67% of the participants reporting one or more symptom(s) were in the ferrous sulphate group. In the first week of the study (treatment) the number of symptoms reported by participants in the ferrous sulphate group (mean?±?SEM?=?6.7?±?1.7) was significantly higher than that for participants in the placebo group (1.2?±?0.5) (p?=?0.01). In the second week of the study (wash-out) the number of symptoms reported by participants in the ferrous sulphate group (4.6?±?2.0) appeared higher than for participants in the placebo group (1.0?±?0.7) although this did not reach significance (p?=?0.12). Events for which the gastrointestinal symptom questionnaire was most discriminatory between ferrous sulphate and placebo groups were: heartburn, abdominal pain and the presence of black stools (all p???0.03). Conclusions A tool for the detection of commonly-occurring side effects should not require large study numbers to be effective. With just 10 subjects per group (iron or placebo), this simple questionnaire measures gastrointestinal side-effects associated with oral iron (ferrous sulphate) supplementation, and would be appropriate for use in intervention studies or clinical trials. Trial registration ClinicalTrials.gov Identifier: NCT02146053 (21/05/2014). PMID:24899360

2014-01-01

172

The Pitsch-Petch orientation relationship in ferrous pearlite at small undercooling  

SciTech Connect

The factors behind the occurrence of the Pitsch-Petch pearlitic orientation relationship (OR) in ferrous systems are investigated using a combination of crystallographic information obtained through electron-backscatter diffraction (EBSD) and knowledge of the three-dimensional (3-D) morphology of pearlite from serial sectioning. Both hypereutectoid and hypoeutectoid ferrous systems of various compositions providing a variety of morphologies are examined to consider the relationship between pearlite nucleation sites and ferrite-cementite interlamellar ORs. It is shown that the Pitsch-Petch OR occurs when a colony is cementite nucleated and this conclusion is valid for both sides of the eutectoid composition.

Mangan, M.A.; Shiflet, G.J.

1999-11-01

173

Chelating versatility of toxic metal resistant microorganisms  

SciTech Connect

Thorium- and uranium-resistant strains of Pseudomonas aeruginosa when grown in high concentration of these metals (100 to 1000 ppM) in citrate- or succinate-containing media produce several chelating agents. Crude extracts of the metal-induced products, when tested for their toxicity and decorporation potential from mammalian tissues have shown that their efficiency is comparable to DTPA (Diethylene triamine pentaacetic acid) and DFOA (Desferrioxamine). Washed biomass of P. aeruginosa also bioaccumulates heavy metals. Bioaccumulation is selective and several microorganisms have been tested for selective adsorption of uranium, thorium, cobalt, chromium, manganese, tin, and platinum. The results have shown that P. aeruginosa CSU has a preference for uranium, while P. aeruginosa PAO-1 and P. fluorescens exhibit a preference for thorium, and Aspergillus niger is selective for chromium and thorium. 8 refs., 3 figs., 2 tabs.

Premuzic, E.T.; Lin, M.

1985-05-01

174

Luminescent polyaminocarboxylate chelates of terbium and europium. The effect of chelate structure  

Microsoft Academic Search

We have synthesized and spectrally characterized a series of new luminescent lanthanide complexes based on linear and macrocycle polyaminocarboxylate chelates, covalently joined to an organic sensitizer 7-amino-4-methyl-2(1H)-quinolinone (carbostyril 124). These complexes are luminescent with both terbium and europium and have millisecond lifetime, sharply spiked emission spectra (<10 nm fwhm), large Stokes shifts (>150 nm), excellent solubility, moderate absorption (12000 M⁻¹

Min Li; Paul R. Selvin

1995-01-01

175

Nanoparticle and iron chelators as a potential novel Alzheimer therapy.  

PubMed

Current therapies for Alzheimer disease (AD) such as the acetylcholinesterase inhibitors and the latest NMDA receptor inhibitor, Namenda, provide moderate symptomatic delay at various stages of the disease, but do not arrest the disease progression or bring in meaningful remission. New approaches to the disease management are urgently needed. Although the etiology of AD is largely unknown, oxidative damage mediated by metals is likely a significant contributor since metals such as iron, aluminum, zinc, and copper are dysregulated and/or increased in AD brain tissue and create a pro-oxidative environment. This role of metal ion-induced free radical formation in AD makes chelation therapy an attractive means of dampening the oxidative stress burden in neurons. The chelator desferrioxamine, FDA approved for iron overload, has shown some benefit in AD, but like many chelators, it has a host of adverse effects and substantial obstacles for tissue-specific targeting. Other chelators are under development and have shown various strengths and weaknesses. Here, we propose a novel system of chelation therapy through the use of nanoparticles. Nanoparticles conjugated to chelators show unique ability to cross the blood-brain barrier (BBB), chelate metals, and exit through the BBB with their corresponding complexed metal ions. This method may provide a safer and more effective means of reducing the metal load in neural tissue, thus attenuating the harmful effects of oxidative damage and its sequelae. Experimental procedures are presented in this chapter. PMID:20013176

Liu, Gang; Men, Ping; Perry, George; Smith, Mark A

2010-01-01

176

Chelation: Harnessing and Enhancing Heavy Metal Detoxification—A Review  

PubMed Central

Toxic metals such as arsenic, cadmium, lead, and mercury are ubiquitous, have no beneficial role in human homeostasis, and contribute to noncommunicable chronic diseases. While novel drug targets for chronic disease are eagerly sought, potentially helpful agents that aid in detoxification of toxic elements, chelators, have largely been restricted to overt acute poisoning. Chelation, that is multiple coordination bonds between organic molecules and metals, is very common in the body and at the heart of enzymes with a metal cofactor such as copper or zinc. Peptides glutathione and metallothionein chelate both essential and toxic elements as they are sequestered, transported, and excreted. Enhancing natural chelation detoxification pathways, as well as use of pharmaceutical chelators against heavy metals are reviewed. Historical adverse outcomes with chelators, lessons learned in the art of using them, and successes using chelation to ameliorate renal, cardiovascular, and neurological conditions highlight the need for renewed attention to simple, safe, inexpensive interventions that offer potential to stem the tide of debilitating, expensive chronic disease. PMID:23690738

Sears, Margaret E.

2013-01-01

177

Ferrous iron oxidation and leaching of copper ore with halotolerant bacteria in ore columns  

Microsoft Academic Search

Growth on ferrous iron of a new isolate of the acidophile Thiobacillus prosperus occurred with a substrate oxidation rate similar to that of Acidithiobacillus ferrooxidans. As well as similar capacities for iron oxidation, these species were shown to possess similar, but not identical, clusters of genes (the rus operon) that encode proteins likely to be involved in transfer of electrons

Carol S. Davis-Belmar; James Le C. Nicolle; Paul R. Norris

2008-01-01

178

COMBINATION LIMESTONE-LIME NEUTRALIZATION OF FERROUS IRON ACID MINE DRAINAGE  

EPA Science Inventory

Studies were conducted on ferrous-iron acid mine drainage (AMD) treatment by a two-step neutralization process in which rock-dust limestone was mixed with the influent AMD and then hydrated lime was added in a polishing reactor. This combination treatment process resulted in reag...

179

ANALYSIS OF FERRIC AND FERROUS IONS IN SOIL EXTRACTS BY ION CHROMATOGRAPHY  

EPA Science Inventory

A method using ion chromatography (IC) for the analysis of ferrous (Fe 2+) and ferric (Fe 3+) ions in soil extracts has been developed. This method uses an ion exchange column with detection at 520 nm after post-column derivatization. Selectivity is achieved by using an anionic...

180

Valorization of rapeseed meal. 4. Effects of iodine, copper and ferrous salt supplementation in growing rats  

E-print Network

Valorization of rapeseed meal. 4. Effects of iodine, copper and ferrous salt supplementation), in particular isothiocyanates (ITC) and thiocyanate ions which compete with iodine for thyroidal transport goitrin, inhibit iodine oxidation, a key stage in thyroid hormone synthesis (Bergner and Schmidt, 1972

Paris-Sud XI, Université de

181

IN SITU CR(VI) TREATMENT USING A FERROUS IRON-BASED REDUCTANT  

EPA Science Inventory

Laboratory and field studies were conducted to evaluate the performance of a ferrous sulfate/ sodium hydrosulfite (dithionite) reductant blend in treating a hexavalent chromium (Cr(VI)) source area and Cr(VI) dissolved phase plume at a former industrial site in Charleston, South ...

182

Net photosynthesis and chlorophyll content in silver maple after trunk injection of ferrous sulfate  

Microsoft Academic Search

Chlorotic silver maple (Acer sacoharinum L.) trees growing in a high pH soil were pressure injected with 1800 ml of a 1.0% (w: w) solution of ferrous sulfate. Net photosynthesis (Pn) of treated branches increased to at least eight times that of the control within two weeks after injection. Chlorophyll in treated branches also increased rapidly for the first two

A. K. Hurley; R. H. Valser; T. D. Davis

1986-01-01

183

Ceric and ferrous dosimeters show precision for 50-5000 rad range  

NASA Technical Reports Server (NTRS)

Ammonium thiocyanate, added to the usual ferrous sulfate dosimeter solution, yielded a very stable, precise and temperature-independent system eight times as sensitive as the classical Fricke system in the 50 to 5000 rad range. The ceric dosimeters, promising for use in mixed radiation fields, respond nearly independently of LET.

Frigerio, N. A.; Henry, V. D.

1968-01-01

184

Development of ferrous laminated composites with unique microstructures by control of carbon diffusion  

Microsoft Academic Search

A novel method is described for preparing ferrous laminated composites, containing ultrahigh carbon steel as one of the components, which results in hard and soft layers bounded by sharp and discrete interfaces. The method is based on increasing the activity of carbon in iron by silicon addition; in this manner, the carbon is made to segregate into specific layers by

D. W. Kum; T. Oyama; O. A. Ruano; O. D. Sherby

1986-01-01

185

Health risk for children from lead and cadmium near a non-ferrous smelter in Bulgaria  

Microsoft Academic Search

In an interdisciplinary approach the exposure to lead and cadmium of the population living in the vicinity of a Bulgarian non-ferrous metallurgical plant was studied to determine the routes of exposure. Two exposed villages situated 4 and 6 km SW and W, respectively, – in the plume of the plant's emissions – and a village for comparison situated 14 km

A. B. Fischer; R. Georgieva; V. Nikolova; J. Halkova; A. Bainova; V. Hristeva; D. Penkov; D. Alandjiisk

2003-01-01

186

Differential Protein Expression during Growth of Acidithiobacillus ferrooxidans on Ferrous Iron, Sulfur Compounds, or Metal Sulfides  

PubMed Central

A set of proteins that changed their levels of synthesis during growth of Acidithiobacillus ferrooxidans ATCC 19859 on metal sulfides, thiosulfate, elemental sulfur, and ferrous iron was characterized by using two-dimensional polyacrylamide gel electrophoresis. N-terminal amino acid sequencing and mass spectrometry analysis of these proteins allowed their identification and the localization of the corresponding genes in the available genomic sequence of A. ferrooxidans ATCC 23270. The genomic context around several of these genes suggests their involvement in the energetic metabolism of A. ferrooxidans. Two groups of proteins could be distinguished. The first consisted of proteins highly upregulated by growth on sulfur compounds (and downregulated by growth on ferrous iron): a 44-kDa outer membrane protein, an exported 21-kDa putative thiosulfate sulfur transferase protein, a 33-kDa putative thiosulfate/sulfate binding protein, a 45-kDa putative capsule polysaccharide export protein, and a putative 16-kDa protein of unknown function. The second group of proteins comprised those downregulated by growth on sulfur (and upregulated by growth on ferrous iron): rusticyanin, a cytochrome c552, a putative phosphate binding protein (PstS), the small and large subunits of ribulose biphosphate carboxylase, and a 30-kDa putative CbbQ protein, among others. The results suggest in general a separation of the iron and sulfur utilization pathways. Rusticyanin, in addition to being highly expressed on ferrous iron, was also newly synthesized, as determined by metabolic labeling, although at lower levels, during growth on sulfur compounds and iron-free metal sulfides. During growth on metal sulfides containing iron, such as pyrite and chalcopyrite, both proteins upregulated on ferrous iron and those upregulated on sulfur compounds were synthesized, indicating that the two energy-generating pathways are induced simultaneously depending on the kind and concentration of oxidizable substrates available. PMID:15294777

Ramírez, Pablo; Guiliani, Nicolas; Valenzuela, Lissette; Beard, Simon; Jerez, Carlos A.

2004-01-01

187

Cell assay using a two-photon-excited europium chelate  

PubMed Central

We report application of two-photon excitation of europium chelates to immunolabeling of epidermal growth factor receptor (EGFR) cell surface proteins on A431 cancer cells. The europium chelates are excited with two photons of infrared light and emit in the visible. Europium chelates are conjugated to antibodies for EGFR. A431 (human epidermoid carcinoma) cells are labeled with this conjugate and imaged using a multiphoton microscope. To minimize signal loss due to the relatively long-lived Eu3+ emission, the multiphoton microscope is used with scanning laser two-photon excitation and non-scanning detection with a CCD. The chelate labels show very little photobleaching (less than 1% during continuous illumination in the microscope for 20 minutes) and low levels of autofluorescence (less than 1% of the signal from labeled cells). The detection limit of the europium label in the cell assay is better than 100 zeptomoles. PMID:21833362

Xiao, Xudong; Haushalter, Jeanne P.; Kotz, Kenneth T.; Faris, Gregory W.

2011-01-01

188

Metal chelate process to remove pollutants from fluids  

DOEpatents

The present invention relates to improved methods using an organic iron chelate to remove pollutants from fluids, such as flue gas. Specifically, the present invention relates to a process to remove NO[sub x] and optionally SO[sub 2] from a fluid using a metal ion (Fe[sup 2+]) chelate wherein the ligand is a dimercapto compound wherein the --SH groups are attached to adjacent carbon atoms (HS--C--C--SH) or (SH--C--CCSH) and contain a polar functional group so that the ligand of DMC chelate is water soluble. Alternatively, the DMC is covalently attached to a water insoluble substrate such as a polymer or resin, e.g., polystyrene. The chelate is regenerated using electroreduction or a chemical additive. The dimercapto compound bonded to a water insoluble substrate is also useful to lower the concentration or remove hazardous metal ions from an aqueous solution. 26 figures.

Chang, S.G.T.

1994-12-06

189

Comparing potential copper chelation mechanisms in Parkinson's disease protein  

NASA Astrophysics Data System (ADS)

We have implemented the nudged elastic band (NEB) as a guided dynamics framework for our real-space multigrid method of DFT-based quantum simulations. This highly parallel approach resolves a minimum energy pathway (MEP) on the energy hypersurface by relaxing intermediates in a chain-of-states. As an initial application we present an investigation of chelating agents acting on copper ion bound to ?-synuclein, whose misfolding is implicated in Parkinson's disease (PD). Copper ions are known to act as highly effective misfolding agents in a-synuclein and are thus an important target in understanding PD. Furthermore, chelation therapy has shown promise in the treatment of Alzheimer's and other neuro-degenerative diseases with similar metal-correlated pathologies. At present, our candidate chelating agents include nicotine, curcumin and clioquinol. We examine their MEP activation barriers in the context of a PD onset mechanism to assess the viability of various chelators for PD remediation.

Rose, Frisco; Hodak, Miroslav; Bernholc, Jerry

2011-03-01

190

Ligation of water to magnesium chelates of biological importance.  

PubMed

Water binding to several Mg(2+) chelates, ethylenediamine, ethylenediamine-N,N'-diacetate, porphyrin, chlorophyll a and bacteriochlorophyll a, to form five- and six-coordinate complexes is studied by means of density functional theory. The results obtained for magnesium chelates are compared with the properties of the respective aqua complexes and the influence of the permittivity of environment on the ligand binding energies is discussed. Although the most common coordination number of Mg(2+) is six, in the tetrapyrrolic chelates it is reduced to five because the accommodation of the sixth water ligand results in no gain in energy. This is in line with the experimental observations made for coordination of chlorophylls in vivo. The binding between Mg(2+) and water is mostly of electrostatic nature, which is supported by the finding that its energy is correlated both with the electron density of the chelator and with electrostatic potential determined at the ligand binding site. PMID:22643978

Rutkowska-Zbik, Dorota; Witko, Ma?gorzata; Fiedor, Leszek

2013-11-01

191

An Evaluation of the Chelating Agent EDDS for Marigold Production  

Technology Transfer Automated Retrieval System (TEKTRAN)

Aminopolycarboxylic acid (APCA) ligands (chelating agents) like ethylenediaminetetraacetic acid (EDTA) and diethylenetriaminepentaacetic acid (DTPA) are commonly used in soluble fertilizers to supply copper (Cu), iron (Fe), manganese (Mn), and/or zinc (Zn) to plants. The offsite runoff and contamina...

192

3-hydroxy-2(1H)-pyridinone chelating agents  

DOEpatents

Disclosed is a series of improved chelating agents and the chelates formed from these agents, which are highly effective upon both injection and oral administration. Several of the most effective are of low toxicity. These chelating agents incorporate within their structure 3-hydroxy-2-pyridinone (3,2-HOPO) moieties with a substituted carbamoyl group ortho to the hydroxy group of the hydroxypyridinone ring. The electron-withdrawing carbamoyl group increases the acidity, as well as the chemical stability towards oxidation and reduction, of the hydroxypyridinones. In the metal complexes of the chelating agents, the amide protons form very strong hydrogen bonds with the adjacent HOPO oxygen donor, making these complexes very stable at physiological conditions. The terminal N-substituents provide a certain degree of lipophilicity to the 3,2-HOPO, increasing oral activity.

Raymond, Kenneth (Berkeley, CA); Xu, Jide (Berkeley, CA)

1999-01-01

193

3-hydroxy-2(1H)-pyridinone chelating agents  

DOEpatents

Disclosed is a series of improved chelating agents and the chelates formed from these agents, which are highly effective upon both injection and oral administration. Several of the most effective are of low toxicity. These chelating agents incorporate within their structure 3-hydroxy-2-pyridinone (3,2-HOPO) moieties with a substituted carbamoyl group ortho to the hydroxy group of the hydroxypyridinone ring. The electron-withdrawing carbamoyl group increases the acidity, as well as the chemical stability towards oxidation and reduction, of the hydroxypyridinones. In the metal complexes of the chelating agents, the amide protons form very strong hydrogen bonds with the adjacent HOPO oxygen donor, making these complexes very stable at physiological conditions. The terminal N-substituents provide a certain degree of lipophilicity to the 3,2-HOPO, increasing oral activity. 2 figs.

Raymond, K.; Xu, J.

1999-04-06

194

Metal chelate process to remove pollutants from fluids  

DOEpatents

The present invention relates to improved methods using an organic iron chelate to remove pollutants from fluids, such as flue gas. Specifically, the present invention relates to a process to remove NO.sub.x and optionally SO.sub.2 from a fluid using a metal ion (Fe.sup.2+) chelate wherein the ligand is a dimercapto compound wherein the --SH groups are attached to adjacent carbon atoms (HS--C--C--SH) or (SH--C--CCSH) and contain a polar functional group so that the ligand of DMC chelate is water soluble. Alternatively, the DMC' is covalently attached to a water insoluble substrate such as a polymer or resin, e.g., polystyrene. The chelate is regenerated using electroreduction or a chemical additive. The dimercapto compound bonded to a water insoluble substrate is also useful to lower the concentration or remove hazardous metal ions from an aqueous solution.

Chang, Shih-Ger T. (El Cerrito, CA)

1994-01-01

195

Sandstone Acidizing Using Chelating Agents and their Interaction with Clays  

E-print Network

. GLDA fluids kept more amounts of minerals in the solution when compared with HEDTA fluids. Sodium-based chelates when mixed with HF acid showed inhibited performance due to the formation of sodium fluorosilicates precipitates which are insoluble damage...

George, Noble Thekkemelathethil 1987-

2013-01-09

196

Strategies for the preparation of bifunctional gadolinium(III) chelators  

PubMed Central

The development of gadolinium chelators that can be easily and readily linked to various substrates is of primary importance for the development high relaxation efficiency and/or targeted magnetic resonance imaging (MRI) contrast agents. Over the last 25 years a large number of bifunctional chelators have been prepared. For the most part, these compounds are based on ligands that are already used in clinically approved contrast agents. More recently, new bifunctional chelators have been reported based on complexes that show a more potent relaxation effect, faster complexation kinetics and in some cases simpler synthetic procedures. This review provides an overview of the synthetic strategies used for the preparation of bifunctional chelators for MRI applications. PMID:22375102

Frullano, Luca; Caravan, Peter

2012-01-01

197

Minding Metals: Tailoring Multifunctional Chelating Agents for Neurodegenerative Disease  

PubMed Central

Neurodegenerative diseases like Alzheimer's and Parkinson's disease are associated with elevated levels of iron, copper, and zinc and consequentially high levels of oxidative stress. Given the multifactorial nature of these diseases, it is becoming evident that the next generation of therapies must have multiple functions to combat multiple mechanisms of disease progression. Metal-chelating agents provide one such function as an intervention for ameliorating metal-associated damage in degenerative diseases. Targeting chelators to adjust localized metal imbalances in the brain, however, presents significant challenges. In this perspective, we focus on some noteworthy advances in the area of multifunctional metal chelators as potential therapeutic agents for neurodegenerative diseases. In addition to metal chelating ability, these agents also contain features designed to improve their uptake across the blood-brain barrier, increase their selectivity for metals in damage-prone environments, increase antioxidant capabilities, lower A? peptide aggregation, or inhibit disease-associated enzymes such as monoamine oxidase and acetylcholinesterase. PMID:20162187

Perez, Lissette R.; Franz, Katherine J.

2010-01-01

198

Probing chelation motifs in HIV integrase inhibitors  

PubMed Central

A series of HIV integrase (HIV-1 IN) inhibitors were synthesized to evaluate the role of the metal-binding group (MBG) in this class of metalloenzyme inhibitors. A total of 21 different raltegravir-chelator derivative (RCD) compounds were prepared that differed only in the nature of the MBG. These IN strand-transfer inhibitors (INSTIs) were evaluated in vitro in cell-free enzyme activity assays, and the in vitro results were further validated in cell culture experiments. All of the active compounds showed selective inhibition of the strand-transfer reaction over 3?-processing, suggesting a common mode of action with raltegravir. The results of the in vitro activity suggest that the nature of the MBG donor atoms, the overall MBG structure, and the specific arrangement of the MBG donor atom triad are essential for obtaining maximal HIV-1 IN inhibition. At least two compounds (RCD-4, RCD-5) containing a hydroxypyrone MBG were found to display superior strand-transfer inhibition when compared to an abbreviated analogue of raltegravir (RCD-1). By isolating and examining the role of the MBG in a series of INSTIs, we have identified a scaffold (hydroxypyrones) that may provide access to a unique class of HIV-1 IN inhibitors, and may help overcome rising raltegravir resistance. PMID:22308350

Agrawal, Arpita; DeSoto, Jamie; Fullagar, Jessica L.; Maddali, Kasthuraiah; Rostami, Shahrzad; Richman, Douglas D.; Pommier, Yves; Cohen, Seth M.

2012-01-01

199

Potentials and drawbacks of chelate-enhanced phytoremediation of soils  

Microsoft Academic Search

Chelate-enhanced phytoremediation has been proposed as an effective tool for the extraction of heavy metals from soils by plants. However, side-effects related to the addition of chelates, e.g. metal leaching and effects on soil micro-organisms, were usually neglected. Therefore, greenhouse and lysimeter studies were conducted to study the phytoremedation potential of EDGA and citric acid and to evaluate its effects

P. F. A. M. Römkens; Lucas Bouwman; Jan Japenga; Cathrina Draaisma

2002-01-01

200

Iron chelators ICL670 and 311 inhibit HIV-1 transcription  

SciTech Connect

HIV-1 replication is induced by an excess of iron and iron chelation by desferrioxamine (DFO) inhibits viral replication by reducing proliferation of infected cells. Treatment of cells with DFO and 2-hydroxy-1-naphthylaldehyde isonicotinoyl hydrazone (311) inhibit expression of proteins that regulate cell-cycle progression, including cycle-dependent kinase 2 (CDK2). Our recent studies showed that CDK2 participates in HIV-1 transcription and viral replication suggesting that inhibition of CDK2 by iron chelators might also affect HIV-1 transcription. Here we evaluated the effect of a clinically approved orally effective iron chelator, 4-[3,5-bis-(hydroxyphenyl)-1,2,4-triazol-1-yl]-benzoic acid (ICL670) and 311 on HIV-1 transcription. Both ICL670 and 311 inhibited Tat-induced HIV-1 transcription in CEM-T cells, 293T and HeLa cells. Neither ICL670 nor 311 induced cytotoxicity at concentrations that inhibited HIV-1 transcription. The chelators decreased cellular activity of CDK2 and reduced HIV-1 Tat phosphorylation by CDK2. Neither ICL670A or 311 decreased CDK9 protein level but significantly reduced association of CDK9 with cyclin T1 and reduced phosphorylation of Ser-2 residues of RNA polymerase II C-terminal domain. In conclusion, our findings add to the evidence that iron chelators can inhibit HIV-1 transcription by deregulating CDK2 and CDK9. Further consideration should be given to the development of iron chelators for future anti-retroviral therapeutics.

Debebe, Zufan; Ammosova, Tatyana [Center for Sickle Cell Disease, Howard University College of Medicine, 520 W. St., N.W., Washington, DC 20060 (United States); Jerebtsova, Marina [Children's National Medical Center, CRI Center for Cancer and Immunology, 111 Michigan Ave., N.W., Washington, DC 20060 (United States); Kurantsin-Mills, Joseph [Department of Biophysics and Physiology, Howard University College of Medicine, 520 W. St., N.W., Washington, DC 20060 (United States); Niu, Xiaomei; Charles, Sharroya [Center for Sickle Cell Disease, Howard University College of Medicine, 520 W. St., N.W., Washington, DC 20060 (United States); Richardson, Des R. [Iron Metabolism and Chelation Program, Department of Pathology, Blackburn Building (D06), University of Sydney, Sydney, New South Wales, 2006 Australia (Australia); Ray, Patricio E. [Children's National Medical Center, CRI Center for Cancer and Immunology, 111 Michigan Ave., N.W., Washington, DC 20060 (United States); Gordeuk, Victor R. [Center for Sickle Cell Disease, Howard University College of Medicine, 520 W. St., N.W., Washington, DC 20060 (United States); Nekhai, Sergei [Center for Sickle Cell Disease, Howard University College of Medicine, 520 W. St., N.W., Washington, DC 20060 (United States); Department of Biochemistry and Molecular Biology, Howard University College of Medicine, 520 W. St., N.W., Washington, DC 20060 (United States)], E-mail: snekhai@howard.edu

2007-10-25

201

Extraction of metals using supercritical fluid and chelate forming legand  

DOEpatents

A method of extracting metalloid and metal species from a solid or liquid material by exposing the material to a supercritical fluid solvent containing a chelating agent is described. The chelating agent forms chelates that are soluble in the supercritical fluid to allow removal of the species from the material. In preferred embodiments, the extraction solvent is supercritical carbon dioxide and the chelating agent is a fluorinated .beta.-diketone. In especially preferred embodiments the extraction solvent is supercritical carbon dioxide, and the chelating agent comprises a fluorinated .beta.-diketone and a trialkyl phosphate, or a fluorinated .beta.-diketone and a trialkylphosphine oxide. Although a trialkyl phosphate can extract lanthanides and actinides from acidic solutions, a binary mixture comprising a fluorinated .beta.-diketone and a trialkyl phosphate or a trialkylphosphine oxide tends to enhance the extraction efficiencies for actinides and lanthanides. The method provides an environmentally benign process for removing contaminants from industrial waste without using acids or biologically harmful solvents. The method is particularly useful for extracting actinides and lanthanides from acidic solutions. The chelate and supercritical fluid can be regenerated, and the contaminant species recovered, to provide an economic, efficient process.

Wai, Chien M. (Moscow, ID); Laintz, Kenneth E. (Los Alamos, NM)

1998-01-01

202

Method for preparing radionuclide-labeled chelating agent-ligand complexes  

DOEpatents

Radionuclide-labeled chelating agent-ligand complexes that are useful in medical diagnosis or therapy are prepared by reacting a radionuclide, such as .sup.90 Y or .sup.111 In, with a polyfunctional chelating agent to form a radionuclide chelate that is electrically neutral; purifying the chelate by anion exchange chromatography; and reacting the purified chelate with a targeting molecule, such as a monoclonal antibody, to form the complex.

Meares, Claude F. (Davis, CA); Li, Min (Davis, CA); DeNardo, Sally J. (El Macero, CA)

1999-01-01

203

Mercury Binding to the Chelation Therapy Agents DMSA and DMPS and the Rational Design of Custom Chelators for Mercury  

Microsoft Academic Search

Clinical chelation therapy of mercury poisoning generally uses one or both of two drugss meso-dimercaptosuccinic acid (DMSA) and dimercaptopropanesulfonic acid (DMPS), com- mercially sold as Chemet and Dimaval, respectively. We have used a combination of mercury LIII-edge X-ray absorption spectroscopy and density functional theory calculations to investigate the chemistry of interaction of mercuric ions with each of these chelation therapy

Graham N. George; Roger C. Prince; Jürgen Gailer; Gavin A. Buttigieg; M. Bonner Denton; Hugh H. Harris; Ingrid J. Pickering

2004-01-01

204

The magnesium chelation step in chlorophyll biosynthesis  

SciTech Connect

In photosynthetic organisms, the biogenesis of energy transducing membranes requires the coordinate synthesis of prosthetic groups, proteins, and various lipids. Two of the major prosthetic groups, chlorophyll and heme, share a common biosynthetic pathway that diverges at the point of metal insertion into protoporphyrin IX (Proto). Insertion of iron leads to the formation of hemes, while insertion of magnesium is the first step unique to chlorophyll formation. This project is directed toward identifying the enzyme(s) responsible for magnesium chelation and elucidating the mechanism which regulates the flux of precursors through the branch point enzymes in isolated chloroplasts. Using intact chloroplasts from greening cucumber cotyledons, we have confirmed the ATP requirement for Mg-Proto formation. Use of non-hydrolyzable ATP analogs, uncouplers and ionophores has led to the conclusions that ATP hydrolysis is necessary, but that this hydrolysis is not linked to the requirement for membrane intactness by transmembrane ion gradients or electrical potentials. The enzyme(s) are flexible with respect to the porphyrin substrate specificity, accepting porphyrins with -vinyl, -ethyl, or -H substituents at the 2 and 4 positions. The activity increases approximately four-fold during greening. Possible physiological feedback inhibitors such as heme, protochlorophyllide, and chlorophyllide had no specific effect on the activity. The activity has now been assayed in barely, corn and peas, with the system from peas almost ten-fold more active than the cucumber system. Work is continuing in pea chloroplasts with the development of a continuous assay and investigation of the feasibility of characterizing an active, organelle-free preparation. 6 figs.

Weinstein, J.

1990-11-01

205

Affinity purification of copper chelating peptides from chickpea protein hydrolysates.  

PubMed

Chickpea protein hydrolysates obtained with alcalase and flavourzyme were used for purification of copper chelating peptides by affinity chromatography using copper immobilized on solid supports. The chelating activity of purified peptides was indirectly measured by the inhibition of beta-carotene oxidation in the presence of copper. Two protein hydrolysates, obtained after 10 and 100 min of hydrolysis, were the most inhibitory of beta-carotene oxidation. Purified copper chelating peptides from these protein hydrolysates contained 19.7 and 35.1% histidine, respectively, in comparison to 2.7 and 2.6% in the protein hydrolysates. Chelating peptides from hydrolysate obtained after 10 min of hydrolysis were the most antioxidative being 8.3 times more antioxidative than the hydrolysate, while chelating peptides purified from protein hydrolysate obtained after 100 min were 3.1 times more antioxidative than its hydrolysate. However, the histidine content was higher in peptides derived from the 100 min hydrolysate (19.7 against 35.1% in 10 min hydrolysate), indicating that this amino acid is not the only factor involved in the antioxidative activity, and other factors such as peptide size or amino acid sequence are also determinant. This manuscript shows that affinity chromatography is a useful procedure for purification of copper chelating peptides. This method can be extended to other metals of interest in nutrition, such as calcium, iron, or zinc. Purified chelating peptides, in addition to their antioxidative properties, may also be useful in food mineral fortification for increasing the bioavailability of these metals. PMID:17428066

Megías, Cristina; Pedroche, Justo; Yust, Maria M; Girón-Calle, Julio; Alaiz, Manuel; Millan, Francisco; Vioque, Javier

2007-05-16

206

A novel multistep mechanism for oxygen binding to ferrous hemoproteins: rapid kinetic analysis of ferrous-dioxy myeloperoxidase (compound III) formation.  

PubMed

Myeloperoxidase (MPO), a hemoprotein that uses H(2)O(2) as the electron acceptor in the catalysis of oxidative reactions, is implicated as a participant in inflammatory injury and cardiovascular diseases. Mechanisms for turning off this enzyme once released, preventing unwanted tissue injury, are poorly understood. We recently demonstrated that MPO heme reduction causes collapse of the heme pocket, as monitored by significant reductions in the rates of diatomic ligand binding to the heme iron. Using spectral and rapid kinetic measurements, we now demonstrate that molecular oxygen (O(2)) binds to ferrous MPO (MPO-Fe(II)) in a distinct and novel mechanism. Rather than occurring through a simple, reversible, one-step mechanism, as is typical for O(2) binding to other ferrous hemoproteins, the reaction involves several kinetically and spectroscopically distinguishable intermediates. Diode array spectrophotometric and stopped-flow studies reveal that the formation of the MPO-Fe(II)-O(2) complex consists of at least three elementary steps and includes at least two sequential transient intermediates. The first step involves reversible formation of a transient intermediate via an O(2)-dependent mechanism, followed by two sequential O(2)-independent steps that appear to be conformational in origin. Insights into mechanisms for inactivating MPO and the novel mode of O(2) binding to the hemoprotein may provide important clues toward understanding the catalytic action of MPO. PMID:15350145

Abu-Soud, Husam M; Raushel, Frank M; Hazen, Stanley L

2004-09-14

207

Stochastic simulation of gamma radiolysis of acidic ferrous sulfate solution at elevated temperatures.  

PubMed

The effect of temperature on the oxidation of Fe2+ in the gamma radiolysis of acidic ferrous sulfate solutions has been modelled using the stochastic IRT method, incorporating simulated electron track structures. There is an 11% increase in the Fe3+ yield in aerated 0.4 M H2SO4 solution on going from 298 to 573 K (25 to 300 degrees C). The H2 yield in aerated solution increases about 24% from 0.41 at 298 K to 0.51 at 573 K. In the absence of oxygen, the increase in the yields of both Fe3+ and H2 is about 12%. Calculated yields are consistent with available experimental data at room, and elevated temperatures. Simulations for heavy water (D2O) show similar temperature effects to those found for ferrous sulfate solutions in light water (H2O). PMID:12194364

B?gusová, M; Pimblott, S M

2002-01-01

208

Ferrous arrowheads and their oil quench hardening: Some early Indian evidence  

NASA Astrophysics Data System (ADS)

A wide variety of ferrous arrowheads were in use in ancient India. Several typical chemical analyses of arrowheads found from archaeological excavation carried out at Kaushambi are reported in this paper. The average carbon content of these arrowheads varied from as low as 0.1 wt.% to approximately 0.9 wt.%. Literary evidence for oil quench hardening of ferrous arrowheads, as reported in famous Sanskrit epics—the R?m?yana and the Mah?bh?rata—have been discussed in this paper. This type of quench hardening was intentionally adopted as it helped in preventing distortion and formation of quench cracks in arrowheads. The oil quench-hardened arrowheads were rubbed on stones to sharpen them, which also brought about tempering of martensite due to frictional heat.

Dube, R. K.

2008-05-01

209

Possible Association of Ferrous Phosphates and Ferric Sulfates in S-rich Soil on Mars  

NASA Astrophysics Data System (ADS)

NASA Mars Exploration Rover (MER) Spirit explored Gusev Crater to look for signs of ancient aqueous activity, assess past environmental conditions and suitability for life. Spirit excavated light-toned, S-rich soils at several locations. These are likely of hydrothermal, possibly fumarolic origin. At a location dubbed Paso Robles the light-toned soil was also rich in P - a signature from surrounding rock. While S is mainly bound in ferric hydrated sulfates [1], the mineralogy of P is ill-constrained [2]. P is a key element for life and its mineralogy constrains its availability. Ferrous phases observed in Paso Robles Mössbauer spectra may represent olivine and pyroxene from surrounding basaltic soil [1] or ferrous phosphate minerals [3]. Phosphate is well-known to complex and stabilize Fe 2+ against oxidation to Fe 3+ . Schröder et al. [3] proposed a formation pathway of ferrous phosphate/ferric sulfate associations: sulfuric acid reacts with basalt containing apatite, forming CaSO4 and phosphoric acid. The phosphoric and/or excess sulfuric acid reacts with olivine, forming Fe2+-phosphate and sulfate. The phosphate is less soluble and precipitates. Ferrous sulfate remains in solution and is oxidized as pH increases. To verify this pathway, we dissolved Fe2+-chloride and Na-phosphate salts in sulfuric acid inside an anoxic glovebox. The solution was titrated to pH 6 by adding NaOH when a first precipitate formed, which was ferrous phosphate according to Mössbauer spectroscopy (MB). At that point the solution was removed from the glovebox and allowed to evaporate in the presence of atmospheric oxygen, leading to the oxidation of Fe2+. The evaporation rate was controlled by keeping the suspensions at different temperatures; pH was monitored during the evaporation process. The final precipitates were analyzed by MB and X-Ray Fluorescence (XRF), comparable to MER MB and Alpha Particle X-ray Spectrometer instrument datasets, and complementary techniques such as X-ray diffraction. Fourier Transform Infrared spectroscopy measurements to compare to MER miniature thermal emission spectrometer data are planned. We observed differences depending on the heat source during evaporation. The closest match to Martian data on the basis of Mössbauer spectra was achieved with a suspension evaporated at 80°C on a hot plate, i.e. heated from below with a temperature gradient in the bottle. The Fe2+/FeT ratio matched, and ferrous phases were all phosphate. When heated in a water bath, i.e. without a temperature gradient in the bottle, Fe2+/FeT ratios increased and ferrous sulfates precipitated also. These results indicate that the Martian light-toned S-rich deposits formed by evaporation on the surface where temperature gradients would be expected rather than underground. They confirm that ferrous phosphate/ferric sulfate associations are possible on Mars and could be preserved in the oxygen-free Martian atmosphere. References: [1] Morris et al., J.Geophys. Res. 111 (2006) E02S13; [2] Ming et al., J. Geophys. Res. 111 (2006) E02S12; [3] Schröder et al., GSA Annual Meeting 2008, Paper No. 171-3.

Mao, J.; Schroeder, C.; Haderlein, S.

2012-12-01

210

Pilot-plant study of wastewater sludge decontamination using a ferrous sulfate bioleaching process.  

PubMed

The objective of this research was to investigate the performance of the ferrous sulfate bioleaching (FSBL) process in a pilot plant for decontamination and stabilization of wastewater sludge. Batch and continuous experiments, conducted with two 4-m3 bioreactors using indigenous iron-oxidizing bacteria (20% v/v of inoculum) with addition of 4.0 g ferrous sulfate heptahydrate per liter of sludge initially acidified to pH 4.0, were sufficient for effective heavy metal (cadmium, copper, manganese, zinc, and lead) removal yields. The average metal removal yields during the FSBL process were as follows: cadmium (69 to 75%), copper (68 to 70%), manganese (72 to 73%), zinc (65 to 66%), and lead (16%). The FSBL process was also found to be effective in removing both fecal and total coliforms (abatement > 5 to 6 log units). The nutrients content (nitrogen, phosphorus, and magnesium) were also preserved in decontaminated sludge. PMID:17059142

Mercier, Guy; Drogui, Patrick; Blais, Jean-François; Chartier, Myriam

2006-08-01

211

Determination of Partial Molar Volume of Ferrous Iron in Silicate Melts  

NASA Astrophysics Data System (ADS)

The density of silicate liquids and partial molar volumes of oxide components have been a topic of intense study over several decades. Nevertheless, only a handful of density measurements have been performed in ferrous- iron dominated melts. Ferrous iron is among the most important elements in the crust and mantle. Knowledge of the partial molar volume of ferrous iron is critical to calculating phase saturation, exchange equilibrium, density etc. in major rock-forming phases as a function of pressure. We have developed a protocol for measuring density of silicate melts under reducing conditions using a single-bob Archimedean device. We are currently performing density measurements in the CaO-FeO-Al2O3-SiO2 system with the goal of accurately constraining the partial molar volume of ferrous iron as a function of temperature and composition. The device as currently configured uses a Mo crucible and Mo bob assembly. Preliminary work in mildly reducing melts suggest that up to 3 mol% Mo oxide in the silicate melt can coexist with Mo metal. On quench, Mo comes out of solution forming globular "micro-nuggets" and/or dendritic crystals. Under more reducing conditions in Fe-rich compositions, Fe in the silicate reacts with Mo metal to form "micro-nuggets" of equilibrium immiscible Fe-Mo liquid alloy. We believe that under these conditions the Fe content of the melt and the formation of "micro-nuggets" are governed by the reactions: \\begin{eqnarray} {Mo(s) + \\frac{y}{2} O2 \\ (g)} &?& {MoO y \\ ( silicate \\ melt) ? Mo( alloy) + \\frac{y}{2} O2 \\ (g)}\

Dwyer, C. A.; Kress, V. C.

2007-12-01

212

Glass formability of ferrous- and aluminum-based structural metallic alloys  

Microsoft Academic Search

Synthesis of ferrous- and aluminum-based amorphous metals as prospective structural materials is presented and discussed in light of atomic size–composition interaction effects. The search of prospective bulk metallic glasses (BMGs) may benefit from noting that current BMG alloys can be broadly categorized into two atom size-composition classes, distinctly different from ordinary metallic glasses which can exist over a much wider

S. Joseph Poon; Gary J. Shiflet; F. Q. Guo; V. Ponnambalam

2003-01-01

213

Stress corrosion cracking of several high strength ferrous and nickel alloys  

NASA Technical Reports Server (NTRS)

The stress corrosion cracking resistance of several high strength ferrous and nickel base alloys has been determined in a sodium chloride solution. Results indicate that under these test conditions Multiphase MP35N, Unitemp L605, Inconel 718, Carpenter 20Cb and 20Cb-3 are highly resistant to stress corrosion cracking. AISI 410 and 431 stainless steels, 18 Ni maraging steel (250 grade) and AISI 4130 steel are susceptible to stress corrosion cracking under some conditions.

Nelson, E. E.

1971-01-01

214

Equivalent bioavailability of iron from ferrous salts and a ferric polymaltose complex. Clinical and experimental studies.  

PubMed

In both experimental animals and human subjects iron absorption over a wide dosage range was quantitatively equivalent from ferrous salts and a ferric polymaltose complex under basal conditions. The comparable bioavailability was maintained when demand was increased by iron depletion or erythroid stimulation and depressed by expansion of body stores or impaired erythropoiesis. This common pattern for iron retention from both salt and complex supports the interchangeable use of these products in therapy of absolute iron deficiency. PMID:3566865

Jacobs, P

1987-01-01

215

Plant genotype differences to ferrous and total iron in emerging leaves. II. Dry beans and soybeans  

Microsoft Academic Search

Ferrous iron (Iron and Fe) and total Fe were determined in “Fe?tolerant”; and “Fe?susceptible”; dry bean (Phaseolus vulgaris L.; UI 59 and PI 165078) and soybean (Glycine max L.; A2, T203, and Hawkeye) genotypes to evaluate their differential responses to Fe deficiency stress. Plants were grown in growth chambers in solutions with Fe (+Fe) and without Fe (?Fe). Once Fe

E. E. Pierson; R. B. Clark; D. P. Coyne; J. W. Maranville

1984-01-01

216

Enhancement of cytotoxicity of artemisinins toward cancer cells by ferrous iron  

Microsoft Academic Search

Iron(II) heme-mediated activation of the peroxide bond of artemisinins is thought to generate the radical oxygen species responsible for their antimalarial activity. We analyzed the role of ferrous iron in the cytotoxicity of artemisinins toward tumor cells. Iron(II)–glycine sulfate (Ferrosanol) and transferrin increased the cytotoxicity of free artesunate, artesunate microencapsulated in maltosyl-?-cyclodextrin, and artemisinin toward CCRF-CEM leukemia and U373 astrocytoma

Thomas Efferth; Achille Benakis; Marta R. Romero; Maja Tomicic; Rolf Rauh; Daniel Steinbach; Ralf Häfer; Thomas Stamminger; Franz Oesch; Bernd Kaina; Manfred Marschall

2004-01-01

217

Development of ferrous laminated composites with unique microstructures by control of carbon diffusion  

Microsoft Academic Search

A novel method is described for preparing ferrous laminated composites, containing ultrahigh carbon steel as one of the components,\\u000a which results in hard and soft layers bounded by sharp and discrete interfaces. The method is based on increasing the activity\\u000a of carbon in iron by silicon addition; in this manner, the carbon is made to segregate into specific layers by

D. W. Kum; T. Oyama; O. A. Ruano; O. D. Sherby

1986-01-01

218

The role of biomass, electron shuttles, and ferrous iron in the kinetics of Geobacter sulfurreducens-mediated ferrihydrite reduction.  

PubMed

This work presents a new framework for describing biologically mediated reduction of thin layers of poorly crystalline iron oxides. The research here explores the nature of the biomass to surface area relationship and the role of biogenic ferrous iron during Geobacter sulfurreducens-mediated ferrihydrite reduction, with and without an electron shuttle, through experiments and a mathematical model. The results indicate that a saturating function of biomass most accurately describes the rate of iron reduction without electron shuttles, based on the principle of electron transfer via direct contact. This study also finds that the most appropriate model of iron reduction in the presence of electron shuttles includes both a saturating function of biomass for electron transfer via direct contact and a first-order electron transfer to ferrihydrite via the electron shuttle, strongly supporting the idea that G. sulfurreducens uses both pathways simultaneously. In all experiments, G. sulfurreducens reduced less than 60% of the total ferric iron, a phenomenon that has often been explained through the inhibitory effects of biogenic ferrous iron in the dissolved phase. However, through experiments with spikes of ferrous sulfate, this study suggests that the role of dissolved ferrous iron is passive in this case, and does not directly inhibit the extent of iron reduction in ferrihydrite coated sand. These experiments find that solid phase ferrous iron is the most probable primary product of ferrihydrite reduction, and that the conversion of solid ferric iron to solid ferrous iron depletes a fixed pool of bioavailable ferric iron, thereby accounting for the incomplete reduction of ferric iron observed here. This is the first reported model that explicitly treats solid ferrous iron as the primary product of reduction, with aqueous ferrous iron as a passive byproduct. This simple mathematical model readily translates to other systems of microbially mediated iron reduction. PMID:21111440

MacDonald, Luke H; Moon, Hee Sun; Jaffé, Peter R

2011-01-01

219

Development of tridentate iron chelators: from desferrithiocin to ICL670.  

PubMed

Successful treatment of beta-thalassemia requires two key elements: blood transfusion and iron chelation. Regular blood transfusions considerably expand the lifespan of patients, however, without the removal of the consequential accumulation of body iron, few patients live beyond their second decade. In 1963, the introduction of desferrioxamine (DFO), a hexadentate chelator, marked a breakthrough in the treatment of beta-thalassemia. DFO significantly reduces body iron burden and iron-related morbidity and mortality. DFO is still the only drug for general use in the treatment of transfusion dependent iron overload. However, its very short plasma half-life and poor oral activity necessitate special modes of application (subcutaneous or intravenous infusion) which are inconvenient, can cause local reactions and are difficult to be accepted by many patients. Over the past four decades, many different laboratories have invested major efforts in the identification of orally active iron chelators from several hundreds of molecules of synthetic, microbial or plant origin. The discovery of ferrithiocin in 1980, followed by the synthesis of the tridentate chelator desferrithiocin and proof of its oral activity raised a lot of hope. However, the compound proved to be toxic in animals. Over a period of about fifteen years many desferrithiocin derivatives and molecules with broader alterations led to the discovery of numerous new compounds some of which were much better tolerated and were more efficacious than desferrithiocin in animals, however, none was safe enough to proceed to the clinical use. The discovery of a new chemical class of iron chelators: The bis-hydroxyphenyltriazoles re-energized the search for a safe tridentate chelator. The basic structure of this completely new chemical class of iron chelators was discovered by a combination of rational design, intuition and experience. More than forty derivatives of the triazole series were synthesized at Novartis. These compounds were evaluated, together with more than 700 chelators from various chemical classes. Using vigorous selection criteria with a focus on tolerability, the tridentate chelator 4-[(3,5-Bis-(2-hydroxyphenyl)-1,2,4)triazol-1-yl]-benzoic acid (ICL670) emerged as an entity which best combined high oral potency and tolerability in animals. ICL670 is presently being evaluated in the clinic. PMID:12678677

Nick, Hanspeter; Acklin, Pierre; Lattmann, René; Buehlmayer, Peter; Hauffe, Suzanne; Schupp, Joachim; Alberti, Daniele

2003-06-01

220

LITERATURE REVIEW: REDUCTION OF NP(V) TO NP (IV)-ALTERNATIVES TO FERROUS SULFAMATE  

SciTech Connect

The baseline approach to control of Np oxidation in UREX and PUREX separation processes is the reduction of Np(V) and Np(VI) to Np(IV) using ferrous sulfamate. Use of this reagent results in increased sulfur and iron concentrations in the liquid waste streams from the process. Presence of these two elements, especially sulfur, increases the complexity of the development of wasteforms for immobilizing these effluents. Investigations are underway to identify reductants that eliminate sulfur and iron from the Np reduction process. While there are a variety of chemical reductants that will reduce Np to Np(IV) in nitric acid media, the reaction rates for most are so slow that the reductants are not be feasible for use in an operating plant process. In an attempt to identify additional alternatives to ferrous sulfamate, a literature search and review was performed. Based on the results of the literature review, it is concluded that photochemical and catalytic processes should also be investigated to test the utility of these two approaches. The catalytic process could be investigated for use in conjunction with chemical oxidants to speed the reaction rates for reductants that react slowly, but would otherwise be appropriate replacements for ferrous sulfamate. The photochemical approach, which has received little attention during the past few decades, also shows promise, especially the photocatalytic approach that includes a catalyst, such as Pt supported on SiC, which can be used in tandem with an oxidant, for Np reduction.

Kessinger, G.; Kyser, E.; Almond, P.

2009-09-28

221

Ferrous iron-dependent delivery of therapeutic agents to the malaria parasite  

PubMed Central

Background The malaria parasites Plasmodium falciparum and Plasmodium vivax generate significant concentrations of free unbound ferrous iron heme as a side product of hemoglobin degradation. The presence of these chemically reactive forms of iron, rare in healthy cells, presents an opportunity for parasite-selective drug delivery. Accordingly, our group is developing technologies for the targeted delivery of therapeutics to the intra-erythrocytic malaria parasite. These so-called ‘fragmenting hybrids’ employ a 1,2,4-trioxolane ring system as an iron(II)-sensing ‘trigger’ moiety and a ‘traceless’ retro-Michael linker to which a variety of partner drug species may be attached. After ferrous iron-promoted activation in the parasite, the partner drug is released via a ?-elimination reaction. Methods In this report, we describe three orthogonal experimental approaches that were explored in order to generate in vitro proof-of-concept for ferrous iron-dependent drug delivery from a prototypical fragmenting hybrid. Conclusion Studies of two fragmenting hybrids by orthogonal approaches confirm that a partner drug species can be delivered to live P. falciparum parasites. A key advantage of this approach is the potential to mask a partner drug’s intrinsic bioactivity prior to release in the parasite. PMID:23234548

Mahajan, Sumit S; Gut, Jiri; Rosenthal, Philip J; Renslo, Adam R

2013-01-01

222

Ferrous iron-dependent drug delivery enables controlled and selective release of therapeutic agents in vivo  

PubMed Central

The precise targeting of cytotoxic agents to specific cell types or cellular compartments is of significant interest in medicine, with particular relevance for infectious diseases and cancer. Here, we describe a method to exploit aberrant levels of mobile ferrous iron (FeII) for selective drug delivery in vivo. This approach makes use of a 1,2,4-trioxolane moiety, which serves as an FeII-sensitive “trigger,” making drug release contingent on FeII-promoted trioxolane fragmentation. We demonstrate in vivo validation of this approach with the Plasmodium berghei model of murine malaria. Malaria parasites produce high concentrations of mobile ferrous iron as a consequence of their catabolism of host hemoglobin in the infected erythrocyte. Using activity-based probes, we successfully demonstrate the FeII-dependent and parasite-selective delivery of a potent dipeptidyl aminopeptidase inhibitor. We find that delivery of the compound in its FeII-targeted form leads to more sustained target inhibition with greatly reduced off-target inhibition of mammalian cathepsins. This selective drug delivery translates into improved efficacy and tolerability. These findings demonstrate the utility of a purely chemical means to achieve selective drug targeting in vivo. This approach may find useful application in parasitic infections and more broadly in any disease state characterized by aberrant production of reactive ferrous iron. PMID:24145449

Deu, Edgar; Chen, Ingrid T.; Lauterwasser, Erica M. W.; Valderramos, Juan; Li, Hao; Edgington, Laura E.; Renslo, Adam R.; Bogyo, Matthew

2013-01-01

223

Isolation and characterization of an acidophilic, heterotrophic bacterium capable of oxidizing ferrous iron.  

PubMed Central

A heterotrophic bacterium, isolated from an acidic stream in a disused pyrite mine which contained copious growths of "acid streamers," displayed characteristics which differentiated it from previously described mesophilic acidophiles. The isolate was obligately acidophilic, with a pH range of 2.0 to 4.4 and an optimum pH of 3.0. The bacterium was unable to fix carbon dioxide but oxidized ferrous iron, although at a slower rate than either Thiobacillus ferrooxidans or Leptospirillum ferrooxidans. Elemental sulfur and manganese(II) were not oxidized. In liquid media, the isolate produced macroscopic streamerlike growths. Microscopic examination revealed that the bacterium formed long (greater than 100 microns) filaments which tended to disintegrate during later growth stages, producing single, motile cells and small filaments. The isolate did not appear to utilize the energy from ferrous iron oxidation. Both iron (ferrous or ferric) and an organic substrate were necessary to promote growth. The isolate displayed a lower tolerance to heavy metals than other iron-oxidizing acidophiles, and growth was inhibited by exposure to light. There was evidence of extracellular sheath production by the isolate. In this and some other respects, the isolate resembles members of the Sphaerotilus-Leptothrix group of filamentous bacteria. The guanine-plus-cytosine content of the isolate was 62 mol%, which is less than that recorded for Sphaerotilus-Leptothrix spp. and greater than those of L. ferrooxidans and most T. ferrooxidans isolates. Images PMID:1622207

Johnson, D B; Ghauri, M A; Said, M F

1992-01-01

224

Iron and pH-responsive FtrABCD ferrous iron utilization system of Bordetella species  

PubMed Central

Summary A putative operon encoding an uncharacterized ferrous iron transport (FtrABCD) system was previously identified in cDNA microarray studies. In growth studies using buffered medium at pH values ranging from pH 6.0 to 7.6, Bordetella pertussis and Bordetella bronchiseptica FtrABCD system mutants showed dramatic reductions in growth yields under iron-restricted conditions at pH 6.0, but had no growth defects at pH 7.6. Supplementation of culture medium with 2 mM ascorbate reductant was inhibitory to alcaligin siderophore-dependent growth at pH 7.6, but had a neglible effect on FtrABCD system-dependent iron assimilation at pH 6.0 consistent with its predicted specificity for ferrous iron. Unlike Bordetella siderophore-dependent and haem iron transport systems, and in agreement with its hypothesized role in transport of inorganic iron from periplasm to cytoplasm, FtrABCD system function did not require the TonB energy transduction complex. Gene fusion analysis revealed that ftrABCD promoter activity was maximal under iron-restricted growth conditions at acidic pH. The pH of human airway surface fluids ranges from pH 5.5 to 7.9, and the FtrABCD system may supply ferrous iron necessary for Bordetella growth in acidic host microenvironments in which siderophores are ineffective for iron retrieval. PMID:22924881

Brickman, Timothy J.; Armstrong, Sandra K.

2012-01-01

225

Oral iron therapy in human subjects, comparative absorption between ferrous salts and iron polymaltose.  

PubMed

Iron absorption was directly compared between equivalent doses of ferrous salts and a polymaltose complex using a twin-isotope technique in which each individual acts as his own control. In the first study, bioavailability of iron from ferrous sulfate and the complex was defined at physiologic doses of 5 mg (Group 1: n = 14) and therapeutic doses of 50 mg (Group 2: n = 13). In Group 1, mean absorption from salt was 47.77% (SD 14.58%) and from polymaltose, 46.56% SD 17.07%). In Group 2, mean absorption from salt was 32.92% (SD 13.42%) and from polymaltose, 27.07% (SD 6.50%). In a second study, 100 mg of iron in a chewable formulation was used to compare absorption between equal doses of ferrous fumarate and the polymaltose complex. Mean absorption from salt was 10.25% (SD 6.89%) and from polymaltose 10.68% (SD 4.68%). At all three dosage levels, iron is equally available from salt or polymaltose for hemoglobin synthesis (p greater than 0.20), and absorption negatively correlated with plasma ferritin (p less than 0.01). These two materials may be used interchangeably in the treatment of patients with absolute iron deficiency. PMID:6599114

Jacobs, P; Johnson, G; Wood, L

1984-01-01

226

New developments in the processing of the non ferrous metal fraction of car scrap  

SciTech Connect

The processing of scrap and scrap cars starts with size reduction by a hammermill, or shredder. After the liberation the magnetic fraction is removed. The remaining nonmagnetic fraction mixed with other materials is screened and each fraction is processed separately. The increased use of plastic has a negative effect on the recovery of metals and waste production. At Huron Valley, Belleville Michigan, USA, the non-ferrous fraction from 5 million obsolete cars per year, containing 200,000 tons of non-ferrous metal, is processed. Aluminium is recovered with a heavy medium separation process and concentrated with eddy current separators. The remaining heavy non-ferrous fraction is concentrated by a new combination of eddy current separation and image processing. After this separation process the zinc fraction is melted and refined and the copper, brass, stainless steel and other high-quality concentrates are sold to the secondary industries. The recycling of car scrap has become an important source of metals and materials for the secondary materials processing industry.

Dalmijn, W.L.; Houwelingen, J.A. van [Delft Univ. of Technology (Netherlands). Faculty of Mining and Petroleum Engineering

1995-12-31

227

Antiproliferative and iron chelating efficiency of the new bis-8-hydroxyquinoline benzylamine chelator S1 in hepatocyte cultures.  

PubMed

If a new generation of iron chelators specifically devoted for cancer chemotherapy emerged these last years, any of them has not yet been approved at this time. Accordingly, there is a need to optimize new chelating molecules for iron chelation therapy and cancer treatment. So, the objective of the present investigation was to characterize the antiproliferative activity and the iron chelating capacity of the iron chelator S1 [bis-N-(8-hydroxyquinoline-5-ylmethyl)benzylamine]. Its effects were compared to O-trensox which binds ferric iron with a very high affinity (pFe(3+)=29.5). For this purpose, primary rat hepatocyte stimulated by EGF and human hepatoma HepaRG cell cultures were used. In these models, the anti-proliferative effect, the inhibition of DNA synthesis and the iron-chelating efficiency of increasing concentrations of S1 and O-trensox (0 up to 200 ?M) were investigated. In the two cell culture models, we observed that S1 was about 100 times more efficient than O-trensox and the antiproliferative effect of S1 in HepaRG cells appeared at concentrations as low as 0.1 ?M without cytotoxicity. Moreover, the stoichiometry of S1 for iron seemed to be in the range S1/Fe(3+)=1. Using the calcein fluorescence assay, we demonstrated that the affinity of S1 for iron was better than that of O-trensox since it was at least two times more effective to restore the fluorescence of calcein previously quenched by iron. So, the iron chelating efficiency of S1 could explain at least partially its higher anti-proliferative effect compared to O-trensox. Finally, these results suggest that molecules such as S1 may constitute a promising starting point to improve cancer treatment. PMID:22197641

Lescoat, Gérard; Léonce, Stéphane; Pierré, Alain; Gouffier, Lucie; Gaboriau, François

2012-01-25

228

Chelation in metal intoxication-Principles and paradigms.  

PubMed

The present review provides an update of the general principles for the investigation and use of chelating agents in the treatment of intoxications by metals. The clinical use of the old chelators EDTA (ethylenediamine tetraacetate) and BAL (2,3-dimercaptopropanol) is now limited due to the inconvenience of parenteral administration, their own toxicity and tendency to increase the neurotoxicity of several metals. The hydrophilic dithiol chelators DMSA (meso-2,3-dimercaptosuccinic acid) and DMPS (2,3-dimercapto-propanesulphonate) are less toxic and more efficient than BAL in the clinical treatment of heavy metal poisoning, and available as capsules for oral use. In copper overload, DMSA appears to be a potent antidote, although d-penicillamine is still widely used. In the chelation of iron, the thiols are inefficient, since iron has higher affinity for ligands with nitrogen and oxygen, but the new oral iron antidotes deferiprone and desferasirox have entered into the clinical arena. Comparisons of these agents and deferoxamine infusions are in progress. General principles for research and development of new chelators are briefly outlined in this review. PMID:25457281

Aaseth, Jan; Skaug, Marit Aralt; Cao, Yang; Andersen, Ole

2014-10-19

229

3-hydroxy-2(1H)-pyridinone chelating agents  

DOEpatents

Disclosed is a series of improved metal chelating agents, which are highly effective upon both injection and oral administration; several of the most effective are of low toxicity. These chelating agents incorporate within their structure 1-hydroxy-2-pyridinone (1,2-HOPO) and 3-hydroxy-2-pyridinone (3,2-HOPO) moieties with a substituted carbamoyl group ortho to the hydroxy or oxo groups of the hydroxypyridinone ring. The electron-withdrawing carbamoyl group increases the acidity of the hydroxypyridinones. In the metal complexes of the chelating agents, the amide protons form very strong hydrogen bonds with its adjacent HOPO oxygen donor, making these complexes very stable at physiological conditions. The terminal N-substituents provides a certain degree of lipophilicity to the 3,2-HOPO, increasing oral activity. Also disclosed is a method of making the chelating agents and a method of producing a known compound, 3-hydroxy-1-alkyl-2(1H)pyridinone, used as a precursor to the chelating agent, safely and in large quantities. 2 figs.

Raymond, K.N.; Xu, J.

1997-04-29

230

3-hydroxy-2(1H)-pyridinone chelating agents  

DOEpatents

Disclosed is a series of improved metal chelating agents, which are highly effective upon both injection and oral administration; several of the most effective are of low toxicity. These chelating agents incorporate within their structure 1-hydroxy-2-pyridinone (1,2-HOPO) and 3-hydroxy-2-pyridinone (3,2-HOPO) moieties with a substituted carbamoyl group ortho to the hydroxy or oxo groups of the hydroxypyridinone ring. The electron-withdrawing carbamoyl group increases the acidity of the hydroxypyridinones. In the metal complexes of said chelating agents, the amide protons form very strong hydrogen bonds with its adjacent HOPO oxygen donor, making these complexes very stable at physiological conditions. The terminal N-substituents provides a certain degree of lipophilicity to said 3,2-HOPO, increasing oral activity. Also disclosed is a method of making the chelating agents and a method of producing a known compound, 3-hydroxy-1-alkyl-2(1H)pyridinone, used as a precursor to the chelating agent, safely and in large quantities.

Raymond, Kenneth N. (Berkeley, CA); Xu, Jide (Berkeley, CA)

1997-01-01

231

Highly regioselective hydroformylation with hemispherical chelators.  

PubMed

The hemispherical diphosphites (R,R)- or (S,S)-5,11,17,23-tetra-tert-butyl-25,27-di(OR)-26,28-bis(1,1'-binaphthyl-2,2'-dioxyphosphanyloxy)calix[4]arene (R=OPr, OCH(2)Ph, OCH(2)-naphtyl, O-fluorenyl; R=H, R'=OPr) (L(R)), all with C(2) symmetry, have been synthesised starting from the appropriate di-O-alkylated calix[4]arene precursor. In the presence of [Rh(acac)(CO)(2)], these ligands straightforwardly provide chelate complexes in which the metal centre sits in a molecular pocket defined by two naphthyl planes related by the C(2) axis and the two apically situated R groups. Hydroformylation of octene with the L(Pr)/Rh system turned out to be highly regioselective, the linear-to-branched (l:b) aldehyde ratio reaching 58:1. The l:b ratio significantly increased when the propyl groups were replaced by -CH(2)Ph (l:b=80) or -CH(2)naphthyl (l:b=100) groups, that is, with substituents able to sterically interact with the apical metal sites, but without inducing an opening of the cleft nesting the catalytic centre. The trend to preferentially form the aldehyde the shape of which fits with the shape of the catalytic pocket was further confirmed in the hydroformylation of styrene, for which, in contrast to catalysis with conventional diphosphanes, the linear aldehyde was the major product (up to ca. 75 % linear aldehyde). In the hydroformylation of trans-2-octene with the L(benzyl)/Rh system, combined isomerisation/hydroformylation led to a remarkably high l:b aldehyde ratios of 25, thus showing that isomerisation is more effective than hydroformylation. Unusually large amounts of linear products were also observed with all the above diphosphites in the tandem hydroformylation/amination of styrene (l:b of ca. 3:1) as well as in the hydroformylation of allyl benzyl ether (l:b ratio up to 20). PMID:18686280

Sémeril, David; Matt, Dominique; Toupet, Loïc

2008-01-01

232

Car–Parrinello molecular dynamics in the DFT + U formalism: Structure and energetics of solvated ferrous and ferric ions  

SciTech Connect

The research described in this product was performed in part in the Environmental Molecular Sciences Laboratory, a national scientific user facility sponsored by the Department of Energy's Office of Biological and Environmental Research and located at Pacific Northwest National Laboratory. We implemented a rotationally-invariant Hubbard U extension to density-functional theory in the Car–Parrinello molecular dynamics framework, with the goal of bringing the accuracy of the DFT + U approach to finite-temperature simulations, especially for liquids or solids containing transition-metal ions. First, we studied the effects on the Hubbard U on the static equilibrium structure of the hexaaqua ferrous and ferric ions, and the inner-sphere reorganization energy for the electron-transfer reaction between aqueous ferrous and ferric ions. It is found that the reorganization energy is increased, mostly as a result of the Fe–O distance elongation in the hexa-aqua ferrous ion. Second, we performed a first-principles molecular dynamics study of the solvation structure of the two aqueous ferrous and ferric ions. The Hubbard term is found to change the Fe–O radial distribution function for the ferrous ion, while having a negligible effect on the aqueous ferric ion. Moreover, the frequencies of vibrations between Fe and oxygen atoms in the first-solvation shell are shown to be unaffected by the Hubbard corrections for both ferrous and ferric ions.

Sit, P H L.; Cococcioni, Matteo; Marzari, Nicola N.

2007-09-01

233

Chelation therapy in intoxications with mercury, lead and copper.  

PubMed

In the present review we provide an update of the appropriate use of chelating agents in the treatment of intoxications with compounds of mercury, lead and copper. The relatively new chelators meso-2,3-dimercaptosuccinic acid (DMSA) and 2,3-dimercapto-propanesulphonate (DMPS) can effectively mobilize deposits of mercury as well as of lead into the urine. These drugs can be administered orally and have relatively low toxicity compared to the classical antidote dimercaptopropanol (BAL). d-Penicillamine has been widely used in copper overload, although 2,3-dimercaptosuccinic acid or tetrathiomolybdate may be more suitable alternatives today. In copper-toxicity, a free radical scavenger might be recommended as adjuvant to the chelator therapy. PMID:24894443

Cao, Yang; Skaug, Marit Aralt; Andersen, Ole; Aaseth, Jan

2014-05-14

234

Inflammation induced by photocoagulation laser is minimized by copper chelators.  

PubMed

The effect of trientine hydrochloride (TRIEN), a copper-selective chelating agent, on retinal inflammation induced by photocoagulation laser treatment was studied. Nine Long-Evans rats were treated with TRIEN (0.5 mmol/kg per day, intraperitoneal injection) for 9 days. On day 8, each animal underwent unilateral photocoagulation laser treatment with an argon dye laser. On day 9, animals were killed and the eyes processed for immunohistochemistry and light microscopy. In the TRIEN-treated group, retinal thickness and number of macrophages (ED-1) were both significantly lower than in the saline-treated, control group exposed to laser photocoagulation. The results support the hypothesis that selective copper chelation prior to laser treatment may inhibit ocular inflammation. The results suggest that pretreatment with a selective copper-chelating compound can minimize retinal inflammation secondary to laser photocoagulation treatment, which may improve overall outcome of photocoagulation treatment for diabetic retinopathy. PMID:18566852

Cui, Jing Z; Wang, Xue-Feng; Hsu, Lena; Matsubara, Joanne A

2009-07-01

235

Molecular nanotechnologies of gelatin-immobilization using macrocyclic metal chelates  

PubMed Central

This article is a review of recent developments in the self-assembled nanostructures based on chelate coordination compounds. Molecular nanotechnologies of self-assembly of 3d-element aza- and thiazametalmacrocyclic complexes that happen in nanoreactors on the basis of metal hexacyanoferrate(II) gelatin-immobilized matrix under their contact with water solutions containing various (N,O,S)-donor atomic ligands and organic compounds having one or two carbonyl groups have been considered in this review. It has been noted that the assortment of macrocyclic metal chelates obtained as a result of using molecular nanotechnologies in such specific conditions considerably differs from the assortment of metal chelates formed at the conditions traditional for chemical synthesis. PMID:24516711

Mikhailov, Oleg V.

2014-01-01

236

Inflammation induced by photocoagulation laser is minimized by copper chelators  

PubMed Central

The effect of trientine hydrochloride (TRIEN), a copper-selective chelating agent, on retinal inflammation induced by photocoagulation laser treatment was studied. Nine Long-Evans rats were treated with TRIEN (0.5 mmol/kg per day, intraperitoneal injection) for 9 days. On day 8, each animal underwent unilateral photocoagulation laser treatment with an argon dye laser. On day 9, animals were killed and the eyes processed for immunohistochemistry and light microscopy. In the TRIEN-treated group, retinal thickness and number of macrophages (ED-1) were both significantly lower than in the saline-treated, control group exposed to laser photocoagulation. The results support the hypothesis that selective copper chelation prior to laser treatment may inhibit ocular inflammation. The results suggest that pretreatment with a selective copper-chelating compound can minimize retinal inflammation secondary to laser photocoagulation treatment, which may improve overall outcome of photocoagulation treatment for diabetic retinopathy. PMID:18566852

Cui, Jing Z.; Wang, Xue-Feng; Hsu, Lena

2014-01-01

237

Histological detection of catalytic ferrous iron with the selective turn-on fluorescent probe RhoNox-1 in a Fenton reaction-based rat renal carcinogenesis model.  

PubMed

Iron overload of a chronic nature has been associated with a wide variety of human diseases, including infection, carcinogenesis, and atherosclerosis. Recently, a highly specific turn-on fluorescent probe (RhoNox-1) specific to labile ferrous iron [Fe(II)], but not to labile ferric iron [Fe(III)], was developed. The evaluation of Fe(II) is more important than Fe(III) in vivo in that Fe(II) is an initiating component of the Fenton reaction. In this study, we applied this probe to frozen sections of an established Fenton reaction-based rat renal carcinogenesis model with an iron chelate, ferric nitrilotriacetate (Fe-NTA), in which catalytic iron induces the Fenton reaction specifically in the renal proximal tubules, presumably after iron reduction. Notably, this probe reacted with Fe(II) but with neither Fe(II)-NTA, Fe(III) nor Fe(III)-NTA in vitro. Prominent red fluorescent color was explicitly observed in and around the lumina of renal proximal tubules 1 h after an intraperitoneal injection of 10-35 mg iron/kg Fe-NTA, which was dose-dependent, according to semiquantitative analysis. The RhoNox-1 signal colocalized with the generation of hydroxyl radicals, as detected by hydroxyphenyl fluorescein (HPF). The results demonstrate the transformation of Fe(III)-NTA to Fe(II) in vivo in the Fe-NTA-induced renal carcinogenesis model. Therefore, this probe would be useful for localizing catalytic Fe(II) in studies using tissues. PMID:24580501

Mukaide, T; Hattori, Y; Misawa, N; Funahashi, S; Jiang, L; Hirayama, T; Nagasawa, H; Toyokuni, S

2014-09-01

238

Interaction of chelating agents with cadmium in mice and rats  

SciTech Connect

The influence of several chelating agents (CaDTPA, ZnDTPA, CaEDTA, ZnEDTA, DMSA, D-penicillamine and DMPS, DMP and DDC) on the acute toxicity of CdCl/sub 2/ and on the whole body retention and tissue distribution of cadmium after the IV application of /sup 115mCdCl/sub 2/ was compared in mice. The chelating agents were applied immediately after the application of cadmium. CaDTPA, ZnDTPA and DMSA appeared to be the most effective antidotes. However, DMSA increased the amount of cadmium retained in kidneys. The treatement of cadmium-poisoned mice with the combination of DMSA (IP) and ZnDTPA (SC) (all the compounds were injected in equimolar dose) decreased the toxicity of cadmium more than treatment with one chelating agents (given in a 2:1 dose). However, by studying the effect of these chelating agents and their combination application of the antidotes showed little or no improvement over the results obtained with the most effective of the individual components. In the urine of rats injected with CdCl/sub 2/ and treated with the chelating agents (CaDTPA, ZnDTPA, DMSA), the presence of cadmium complexes was demonstrated. The formation of mixed ligand chelates in vivo was not proved. Experiments in mice given a single injection of /sup 115m/Cd-labeled Cd complexes of DMPS, DMSA and DTPA showed a high retention of cadmium in the organisms after the IV application of CdDMPS and CdDMSA complexes.

Eybl, V.; Sykora, J.; Koutensky, J.; Caisova, D.; Schwartz, A.; Mertl, F.

1984-03-01

239

Heavy metal displacement in chelate-irrigated soil during phytoremediation  

NASA Astrophysics Data System (ADS)

Heavy metals in wastewater sewage sludge (biosolids), applied to land, contaminate soils. Phytoremediation, the use of plants to clean up toxic heavy metals, might remove them. Chelating agents are added to soil to solubilize the metals for enhanced phytoextraction. Yet no studies follow the displacement and leaching of heavy metals in soil with and without roots following solubilization with chelates. The objective of this work was to determine the mobility of heavy metals in biosolids applied to the surface of soil columns (76 cm long; 17 cm diam.) with or without plants (barley; Hordeum vulgare L.). Three weeks after barley was planted, all columns were irrigated with the disodium salt of the chelating agent, EDTA (ethylenediamine tetraacetic acid) (0.5 g/kg soil). Drainage water, soil, and plants were analyzed for heavy metals (Cd, Cu, Fe, Mn, Ni, Pb, Zn). Total concentrations of the heavy metals in all columns at the end of the experiment generally were lower in the top 30 cm of soil with EDTA than without EDTA. The chelate increased concentrations of heavy metals in shoots. With or without plants, the EDTA mobilized Cd, Fe, Mn, Ni, Pb, and Zn, which leached to drainage water. Drainage water from columns without EDTA had concentrations of these heavy metals below detection limits. Only Cu did not leach in the presence of EDTA. Even though roots retarded the movement of Cd, Fe, Mn, Ni, Pb, and Zn through the EDTA-treated soil from 1 d (Cd) to 5 d (Fe), the drainage water from columns with EDTA had concentrations of Cd, Fe, Mn, and Pb that exceeded drinking water standards by 1.3, 500, 620, and 8.6 times, respectively. Because the chelate rendered Cd, Fe, Mn, Ni, Pb, and Zn mobile, it is suggested that the theory for leaching of soluble salts, put forward by Nielsen and associates in 1965, could be applied to control movement of the heavy metals for maximum uptake during chelate-assisted phytoremediation.

Madrid, F.; Liphadzi, M. S.; Kirkham, M. B.

2003-03-01

240

Combinational chelation therapy abrogates lead-induced neurodegeneration in rats  

SciTech Connect

Lead, a ubiquitous and potent neurotoxicant causes oxidative stress which leads to numerous neurobehavioral and physiological alterations. The ability of lead to bind sulfhydryl groups or compete with calcium could be one of the reasons for its debilitating effects. In the present study, we addressed: i) if chelation therapy could circumvent the altered oxidative stress and prevent neuronal apoptosis in chronic lead-intoxicated rats, ii) whether chelation therapy could reverse biochemical and behavioral changes, and iii) if mono or combinational therapy with captopril (an antioxidant) and thiol chelating agents (DMSA/MiADMSA) is more effective than individual thiol chelator in lead-exposed rats. Results indicated that lead caused a significant increase in reactive oxygen species, nitric oxide, and intracellular free calcium levels along with altered behavioral abnormalities in locomotor activity, exploratory behavior, learning, and memory that were supported by changes in neurotransmitter levels. A fall in membrane potential, release of cytochrome c, and DNA damage indicated mitochondrial-dependent apoptosis. Most of these alterations showed significant recovery following combined therapy with captopril with MiADMSA and to a smaller extend with captopril + DMSA over monotherapy with these chelators. It could be concluded from our present results that co-administration of a potent antioxidant (like captopril) might be a better treatment protocol than monotherapy to counter lead-induced oxidative stress. The major highlight of the work is an interesting experimental evidence of the efficacy of combinational therapy using an antioxidant with a thiol chelator in reversing neurological dystrophy caused due to chronic lead exposure in rats.

Pachauri, Vidhu; Saxena, Geetu; Mehta, Ashish; Mishra, Deepshikha [Division of Pharmacology and Toxicology, Defence Research and Development Establishment, Jhansi Road, Gwalior-474 001 (India); Flora, Swaran J.S. [Division of Pharmacology and Toxicology, Defence Research and Development Establishment, Jhansi Road, Gwalior-474 001 (India)], E-mail: sjsflora@hotmail.com

2009-10-15

241

Ascorbate autoxidation in the presence of iron and copper chelates.  

PubMed

Chelates can inhibit the iron- and copper-catalyzed autoxidation of ascorbate at pH 7.0. Diethylenetriaminepentaacetic acid (DTPA or DETAPAC) and Desferal (deferoximane mesylate) slow the iron-catalyzed oxidation of ascorbate as effectively as reducing the trace levels of contaminating iron in buffers with Chelex resin. DETAPAC, EDTA and HEDTA (N-(2-hydroxyethyl)-ethylenediaminetriacetic acid) are effective at slowing the copper-catalyzed autoxidation of ascorbate while Desferal is ineffective. The ability to inhibit ascorbate autoxidation appears to parallel the rate of the reaction of superoxide with the iron chelate. PMID:2851502

Buettner, G R

1986-01-01

242

Resolution of the electronic transitions of cytochrome c oxidase: evidence for two conformational states of ferrous cytochrome alpha.  

PubMed Central

Second-derivative absorption spectra are reported for a variety of oxidation and ligation states of bovine cytochrome c oxidase (ferrocytochrome-c:oxygen oxidoreductase, EC 1.9.3.1). The high resolving power of the second-derivative method allows us to assign the individual electronic transitions of cytochrome alpha and cytochrome alpha 3 in many of these states. In the fully reduced enzyme, one observes a single electronic transition at 444 nm, corresponding to the Soret transition for both ferrous cytochrome alpha and ferrous cytochrome alpha 3. When the cytochrome alpha 3 site is occupied by an exogenous ligand (CN or CO), one observes two absorption bands assignable to the ferrous cytochrome alpha chromophore, one at ca, 443 nm and the other at ca, 450 nm. The appearance of the 450-nm band is dependent only on ligand occupancy at the cytochrome alpha 3 site and not on the oxidation state of the cytochrome alpha 3 iron. These results can be interpreted either in terms of a heterogeneous mixture of two ferrous cytochrome alpha conformers in the cytochrome alpha 3-ligated enzyme or in terms of a reduction in the effective molecular symmetry of the ferrous cytochrome alpha site that results in a lifting of the degeneracy of the lowest unoccupied molecular orbital associated with the Soret pi,pi* transition of cytochrome alpha. In either case, the present data indicate that ferrous cytochrome alpha can adopt two distinct conformations. One possible structural difference between these two states could be related to differences in the strength of hydrogen bonding between the ferrous cytochrome alpha formyl oxygen and a proton donor from an unidentified amino acid side chain of the enzyme. The implications of such modulation of hydrogen-bond strength are discussed in terms of possible mechanisms of proton translocation and electron transfer in the enzyme. PMID:1852001

Sherman, D; Kotake, S; Ishibe, N; Copeland, R A

1991-01-01

243

Enumeration and Detection of Anaerobic Ferrous Iron-Oxidizing, Nitrate-Reducing Bacteria from Diverse European Sediments  

PubMed Central

Anaerobic, nitrate-dependent microbial oxidation of ferrous iron was recently recognized as a new type of metabolism. In order to study the occurrence of three novel groups of ferrous iron-oxidizing, nitrate-reducing bacteria (represented by strains BrG1, BrG2, and BrG3), 16S rRNA-targeted oligonucleotide probes were developed. In pure-culture experiments, these probes were shown to be suitable for fluorescent in situ hybridization, as well as for hybridization analysis of denaturing gradient gel electrophoresis (DGGE) patterns. However, neither enumeration by in situ hybridization nor detection by the DGGE-hybridization approach was feasible with sediment samples. Therefore, the DGGE-hybridization approach was combined with microbiological methods. Freshwater sediment samples from different European locations were used for enrichment cultures and most-probable-number (MPN) determinations. Bacteria with the ability to oxidize ferrous iron under nitrate-reducing conditions were detected in all of the sediment samples investigated. At least one of the previously described types of bacteria was detected in each enrichment culture. MPN studies showed that sediments contained from 1 × 105 to 5 × 108 ferrous iron-oxidizing, nitrate-reducing bacteria per g (dry weight) of sediment, which accounted for at most 0.8% of the nitrate-reducing bacteria growing with acetate. Type BrG1, BrG2, and BrG3 bacteria accounted for an even smaller fraction (0.2% or less) of the ferrous iron-oxidizing, nitrate-reducing community. The DGGE patterns of MPN cultures suggested that more organisms than those isolated thus far are able to oxidize ferrous iron with nitrate. A comparison showed that among the anoxygenic phototrophic bacteria, organisms that have the ability to oxidize ferrous iron also account for only a minor fraction of the population. PMID:9835573

Straub, Kristina L.; Buchholz-Cleven, Berit E. E.

1998-01-01

244

Extracellular iron chelators protect kidney cells from hypoxia/reoxygenation.  

PubMed

Iron is an important contributor to reoxygenation injury because of its ability to promote hydroxyl radical formation. In previous in vivo studies, we demonstrated that iron chelators that underwent glomerular filtration provided significant protection against postischemic renal injury. An in vitro system was employed to further characterize the protection provided by extracellular iron chelators. Primary cultures of rat proximal tubular epithelial cells were subjected to 60 min hypoxia and 30 min reoxygenation (H/R). During H/R, there was a 67% increase in ferrozine-detectable iron in cell homogenates and increased release of iron into the extracellular space. Cells pretreated with either deferoxamine (DFO) or hydroxyethyl starch-conjugated deferoxamine (HES-DFO), an iron chelator predicted to be confined to the extracellular space, were greatly protected against lethal cell injury. To further localize the site of action of DFO and HES-DFO, tracer quantities of 59Fe were added to DFO or HES-DFO, and their distribution after 2 h was quantitated. Less than 0.1% of DFO entered the cells, whereas essentially none of the HES-DFO was cell-associated. These findings suggest that iron was released during hypoxia/reoxygenation and caused lethal cell injury. Iron chelators confined to the extracellular space provided substantial protection against injury. PMID:7532608

Paller, M S; Hedlund, B E

1994-12-01

245

Efficacy of reversal of aortic calcification by chelating agents.  

PubMed

Elastin-specific medial vascular calcification, termed "Monckeberg's sclerosis," has been recognized as a major risk factor for various cardiovascular events. We hypothesize that chelating agents, such as disodium ethylenediaminetetraacetic acid (EDTA), diethylenetriaminepentaacetic acid (DTPA), and sodium thiosulfate (STS) might reverse elastin calcification by directly removing calcium from calcified tissues into soluble calcium complexes. We assessed the chelating ability of EDTA, DTPA, and STS on removal of calcium from hydroxyapatite (HA) powder, calcified porcine aortic elastin, and calcified human aorta in vitro. We show that both EDTA and DTPA could effectively remove calcium from HA and calcified tissues, while STS was not effective. The tissue architecture was not altered during chelation. In the animal model of aortic elastin-specific calcification, we further show that local periadventitial delivery of EDTA loaded in to poly(lactic-co-glycolic acid) nanoparticles regressed elastin-specific calcification in the aorta. Collectively, the data indicate that elastin-specific medial vascular calcification could be reversed by chelating agents. PMID:23963635

Lei, Yang; Grover, Arjun; Sinha, Aditi; Vyavahare, Naren

2013-11-01

246

Chelation And Extraction Of Metals For GC-MS Analysis  

NASA Technical Reports Server (NTRS)

Chelation followed by supercritical-fluid extraction enables mass-spectrometric analysis. When fully developed, method implemented in field-portable apparatus for detection and quantification of metals in various matrices without need for elaborate preparation of samples. Used to analyze soil samples for toxic metals.

Sinha, Mahadeva P.

1995-01-01

247

Chelators Depigment and Inorease Elasticity of Mink Skin  

Microsoft Academic Search

The effect of subcutaneous injection of four Cu and Fe ion chelators was studied in scanblack minks. The pattern of macromolecular connective tissue components, histology and biochemistry of the skin were analyzed. The purpose of the two experiments performed was to try to establish the influence of age and the interrelationship of skin and hair depigmentation occasionally observed in minks.

Nelly Blumenkrantz; Leena Blomstedt

1987-01-01

248

Desferrithiocin: a search for clinically effective iron chelators.  

PubMed

The successful search for orally active iron chelators to treat transfusional iron-overload diseases, e.g., thalassemia, is overviewed. The critical role of iron in nature as a redox engine is first described, as well as how primitive life forms and humans manage the metal. The problems that derive when iron homeostasis in humans is disrupted and the mechanism of the ensuing damage, uncontrolled Fenton chemistry, are discussed. The solution to the problem, chelator-mediated iron removal, is clear. Design options for the assembly of ligands that sequester and decorporate iron are reviewed, along with the shortcomings of the currently available therapeutics. The rationale for choosing desferrithiocin, a natural product iron chelator (a siderophore), as a platform for structure-activity relationship studies in the search for an orally active iron chelator is thoroughly developed. The study provides an excellent example of how to systematically reengineer a pharmacophore in order to overcome toxicological problems while maintaining iron clearing efficacy and has led to three ligands being evaluated in human clinical trials. PMID:25207964

Bergeron, Raymond J; Wiegand, Jan; McManis, James S; Bharti, Neelam

2014-11-26

249

ORIGINAL ARTICLE Chelated iron sources are inhibitors of Pseudomonas  

E-print Network

-attached communities known as biofilms. These differentiated bacteria possess vastly enhanced antibiotic resistance patterns and vast changes in the expression levels of various proteins. For example, P. aeruginosa biofilms isolates of P. aeruginosa from a local hospital. The chelated iron sources showed excellent distribution

Hergenrother, Paul J.

250

Fluorescence probing of the ferric Fenton reaction via novel chelation.  

PubMed

A new probe-chelator PET dyad was synthesised, which can be used to detect Fe(3+)via fluorescence enhancement to discriminate between Fe(2+) and Fe(3+)via Fenton chemistry involving hydrogen peroxide. This is the first BODIPY which works as a 2?:?1 multiplexer for Fe(3+), Fe(2+) and H2O2. PMID:24247302

Murale, Dhiraj P; Manjare, Sudesh T; Lee, Yoon-Sup; Churchill, David G

2014-01-11

251

Regeneration of the Heart in Diabetes by Selective Copper Chelation  

Microsoft Academic Search

Heart disease is the major cause of death in diabetes, a disorder characterized by chronic hyperglycemia and cardiovascular complications. Although altered system- ic regulation of transition metals in diabetes has been the subject of previous investigation, it is not known whether changed transition metal metabolism results in heart disease in common forms of diabetes and whether metal chelation can reverse

Garth J. S. Cooper; Anthony R. J. Phillips; Soon Y. Choong; Bridget L. Leonard; David J. Crossman; Dianne H. Brunton; Etuate L. Saafi; Ajith M. Dissanayake; Brett R. Cowan; Alistair A. Young; Christopher J. Occleshaw; Yih-Kai Chan; Fiona E. Leahy; Geraldine F. Keogh; Gregory D. Gamble; Grant R. Allen; Adele J. Pope; Peter D. W. Boyd; Sally D. Poppitt; Thomas K. Borg; Robert N. Doughty; John R. Baker

252

The Octahedral-Square-Planar Transition of Nickel Chelates  

NASA Astrophysics Data System (ADS)

An experiment for an advanced inorganic chemistry laboratory is proposed that involves the study of the equilibrium between the (blue) octahedral and (yellow) square planar chelates of nickel(II) with tetraaza ligands in solution. The ligands employed are the linear triethylenetetramine and the cyclic cyclam. Changes in the ionic strength or the temperature of the solutions shift the equilibrium, which is followed spectrophotometrically.

Ben-Dor, Lina; Marcus, Yizhak

1998-11-01

253

Evaluation of intakes of transuranics influenced by chelation therapy  

SciTech Connect

Once an intake of transuranics occurs, there are only three therapeutic procedures available to the physician for reducing the intake and mitigating the dose: excision of material from wounds, removal of material from the lungs with lavage, and chelation therapy. The only chelation agents approved in the United States for the treatment of occupational intakes of transuranics are the zinc and calcium salts of diethylene-triamine-pentaacetic acid, better known as Zn-DTPA and Ca-DTPA. In the past 35 years, approximately 3000 doses of DTPA have been administrated to over 500 individuals who had intakes of transuranics. The drug is considered to be quiet safe and has few side effects. For the internal dosimetrist, perhaps the most important aspects of chelation therapy is that if enhances the excretion rate of a transuranic and perturbs the shape of the urinary excretion curve. These perturbations last for months and are so great that standard urinary excretion models cannot be used to evaluate the intake. We review here a method for evaluating intakes of transuranics influenced by chelation therapy that has been used with some degree of success at the Savannah River Site for over 20 years.

LaBone, T.R.

1994-02-01

254

Phenolic ethylenediamine derivatives: a study of orally effective iron chelators  

SciTech Connect

Of 35 potential iron chelators screened for in vivo activity in rats, a group of phenolic compounds with excellent chelating properties were identified. These included N,N'-ethylene-bis(o-hydroxyphenylglycine) (EHPG), N,N'-Bis(o-hydroxybenzyl)-ethylenediamine diacetic acid (HBED), and their respective dimethyl esters (dmEHPG and dmHBED). All four phenolic compounds produced a marked increase in the fecal excretion of hepatocellular radioiron. This amounted to 42% of total body radioactivity with dmEHPG, 58% with EHPG, 63% with HBED, and 80% with dmHBED after a single injection of 40 mg/animal. At a dose of 5 mg/animal, EHPG, HBED, and dmHBED were 9, 12, and 15 times more potent, respectively, than deferoxamine. Both dimethyl esters showed significant oral activity; oral dmEHPG retained 1/3 and dmHBED retained 2/3 of the effect of the same dose given by intramuscular injection. The ester dmHBED combines oral effectiveness with superior chelating ability, selective hepatocellular action, and low apparent toxicity. It may represent a significant advance in the development of new iron chelating drugs.

Hershko, C.; Grady, R.W.; Link, G.

1984-03-01

255

RESPONSE OF CUCUMBER PLANTS TO LOW DOSES OF DIFFERENT SYNTHETIC IRON CHELATES IN HYDROPONICS  

Technology Transfer Automated Retrieval System (TEKTRAN)

The factors that control the use of the iron provided by iron chelates in strategy I plants are not well known. In this paper we study the effectiveness of low concentrations of a series of pure Fe chelates to supply iron to cucumber plants in hydroponics. The Fe Chelate Reductase (FCR) of the roots...

256

Molecular mechanisms of in vivo metal chelation: implications for clinical treatment of metal intoxications.  

PubMed Central

Successful in vivo chelation treatment of metal intoxication requires that a significant fraction of the administered chelator in fact chelate the toxic metal. This depends on metal, chelator, and organism-related factors (e.g., ionic diameter, ring size and deformability, hardness/softness of electron donors and acceptors, route of administration, bioavailability, metabolism, organ and intra/extracellular compartmentalization, and excretion). In vivo chelation is not necessarily an equilibrium reaction, determined by the standard stability constant, because rate effects and ligand exchange reactions considerably influence complex formation. Hydrophilic chelators most effectively promote renal metal excretion, but they complex intracellular metal deposits inefficiently. Lipophilic chelators can decrease intracellular stores but may redistribute toxic metals to, for example, the brain. In chronic metal-induced disease, where life-long chelation may be necessary, possible toxicity or side effects of the administered chelator may be limiting. The metal selectivity of chelators is important because of the risk of depletion of the patient's stores of essential metals. Dimercaptosuccinic acid and dimercaptopropionic sulfonate have gained more general acceptance among clinicians, undoubtedly improving the management of many human metal intoxications, including lead, arsenic, and mercury compounds. Still, development of new safer chelators suited for long-term oral administration for chelation of metal deposits (mainly iron), is an important research challenge for the future. PMID:12426153

Andersen, Ole; Aaseth, Jan

2002-01-01

257

EDTA Chelation Therapy, Without Added Vitamin C, Decreases Oxidative DNA Damage and Lipid Peroxidation  

Technology Transfer Automated Retrieval System (TEKTRAN)

Chelation therapy is thought to not only remove contaminating metals, but also to decrease free radical production. However, in standard EDTA chelation therapy high doses of vitamin C with potential prooxidant effects are often added to the chelation solution. We demonstrated previously that the in...

258

Ferrous Hydroxy Carbonate is a Stable Transformation Product of Biogenic Magnetite  

SciTech Connect

A ~1:1 mixture of ferrihydrite and nanocrystalline akaganeite (?-FeOOH; 10-15 nm) was incubated with Shewanella putrefaciens (strain CN32) under anoxic conditions with lactate as an electron donor and anthraquinone-2,6-disulfonate (AQDS) as an electron shuttle. The incubation was carried out in a 1,4-piperazinediethanesulfonic acid (PIPES)-buffered medium, without PO?³? at circumneutral pH. Iron reduction was measured as a function of time (as determined by 0.5 N HCl extraction), and solids were characterized by X-ray diffraction (XRD), electron microscopy, and Mössbauer spectroscopy. The biogenic reduction of Fe(III) was rapid; with 60% of the total Fe (Fe???) reduced in one day. Only an additional 10% of Fe??? was reduced over the next three years. A fine-grained (10 nm), cation-excess (CE) magnetite with a Fe(II)/Fe??? ratio of 0.5-0.6 was the sole biogenic product after one day of incubation. The CE magnetite was unstable and partially transformed to micron-sized ferrous hydroxy carbonate [FHC; Fe2 (OH)2CO3?], a rosasite-type mineral, with time. Ferrous hydroxy carbonate dominated the mineral composition of the three year incubated sample. The Fe(II)/Fe??? ratio of the residual CE magnetite after three years of incubation was lower than the day 1 sample and was close to that of stochiometric magnetite (0.33). To best of our knowledge, this is the first report of biogenic FHC, and only the third observation of this material in nature. Ferrous hydroxy carbonate appeared to form by slow reaction of microbially produced carbonate with Fe(II)-excess magnetite. The FHC may be an overlooked mineral phase that explains the infrequent occurrence of fine-grained, biogenic magnetite in anoxic sediments.

Kukkadapu, Ravi K.; Zachara, John M.; Fredrickson, Jim K.; Kennedy, David W.; Dohnalkova, Alice; McCready, David E.

2005-02-02

259

Elucidating the role of ferrous ion cocatalyst in enhancing dilute acid pretreatment of lignocellulosic biomass  

PubMed Central

Background Recently developed iron cocatalyst enhancement of dilute acid pretreatment of biomass is a promising approach for enhancing sugar release from recalcitrant lignocellulosic biomass. However, very little is known about the underlying mechanisms of this enhancement. In the current study, our aim was to identify several essential factors that contribute to ferrous ion-enhanced efficiency during dilute acid pretreatment of biomass and to initiate the investigation of the mechanisms that result in this enhancement. Results During dilute acid and ferrous ion cocatalyst pretreatments, we observed concomitant increases in solubilized sugars in the hydrolysate and reducing sugars in the (insoluble) biomass residues. We also observed enhancements in sugar release during subsequent enzymatic saccharification of iron cocatalyst-pretreated biomass. Fourier transform Raman spectroscopy showed that major peaks representing the C-O-C and C-H bonds in cellulose are significantly attenuated by iron cocatalyst pretreatment. Imaging using Prussian blue staining indicated that Fe2+ ions associate with both cellulose/xylan and lignin in untreated as well as dilute acid/Fe2+ ion-pretreated corn stover samples. Analyses by scanning electron microscopy and transmission electron microscopy revealed structural details of biomass after dilute acid/Fe2+ ion pretreatment, in which delamination and fibrillation of the cell wall were observed. Conclusions By using this multimodal approach, we have revealed that (1) acid-ferrous ion-assisted pretreatment increases solubilization and enzymatic digestion of both cellulose and xylan to monomers and (2) this pretreatment likely targets multiple chemistries in plant cell wall polymer networks, including those represented by the C-O-C and C-H bonds in cellulose. PMID:22074910

2011-01-01

260

Surface complexation of ferrous iron and carbonate on ferrihydrite and the mobilization of arsenic.  

PubMed

Surface complexation models are commonly used to predict the mobility of trace metals in aquifers. For arsenic in groundwater, surface complexation models cannot be used because the database is incomplete. Both carbonate and ferrous iron are often present at a high concentration in groundwater and will influence the sorption of arsenic, but the surface complexation constants are absent in the database of Dzombak and Morel. This paper presents the surface complexation constants for carbonate and ferrous iron on ferrihydrite as derived for the double-layer model. For ferrous iron the constants were obtained from published data supplemented by new experiments to determine the sorption on the strong sites of ferrihydrite. For carbonate the constants were derived from experiments by Zachara et al., who employed relatively low concentrations of carbonate. The double-layer model, optimized for low concentrations, was tested against sorption experiments of carbonate on goethite at higher concentration by Villalobos and Leckie, and reasonable agreement was found. Sorption was also estimated using linear free energy relations (LFER), and results compared well with our derived constants. Model calculations confirm that sorption of particularly carbonate at common soil and groundwater concentrations reduces the sorption capacity of arsenic on ferrihydrite significantly. The displacing effect of carbonate on sorbed arsenate and arsenite has been overlooked in many studies. It may be an important cause for the high concentrations of arsenic in groundwater in Bangladesh. Sediments containing high amounts of sorbed arsenic are deposited in surface water with low carbonate concentrations. Subsequently the sediments become exposed to groundwater with a high dissolved carbonate content, and arsenic is mobilized by displacement from the sediment surface. PMID:12141489

Appelo, C A J; Van Der Weiden, M J J; Tournassat, C; Charlet, L

2002-07-15

261

Suboptimal response to ferrous sulfate in iron-deficient patients taking omeprazole.  

PubMed

Iron deficiency anemia is commonly encountered in outpatient practice. Gastric acid is one of the important factors for optimum absorption of iron. Proton pump inhibitors are very commonly prescribed medications. One of the debated effects of proton pump inhibitors is on oral iron absorption. Their effect on absorption of oral iron supplementation in iron-deficient patients has not been studied. At the Cooper Hematology Outpatient office, we reviewed charts of iron-deficient anemic patients who were on omeprazole for the last 4 years. Fifty patients having no apparent ongoing blood loss, having other causes of anemia especially that of chronic diseases ruled out, and on omeprazole while starting ferrous sulfate therapy for iron deficiency were selected for chart review. The iron-study results at the start of oral ferrous sulfate therapy and at 3 months follow-up were compared to evaluate the response of ferrous sulfate. The mean hemoglobin change was 0.8 ± 1.2 g/L. The mean change in ferrtin values was 10.2 ± 7.8 ?g/L. Only 16% of the patients had a normal response to hemoglobin levels (rise of >2 g/dL), and only 40% had a normal response to ferritin levels (rise of >20 ?g/dL). The average age of patients having a suboptimal response to both hemoglobin and ferritin was significantly higher compared with that of the patients with an optimal response. Omeprazole and possibly all proton pump inhibitors decrease the absorption of oral iron supplementation. Iron-deficient patients taking proton pump inhibitors may have to be treated with high dose iron therapy for a longer duration or with intravenous iron therapy. PMID:21150767

Ajmera, Akash V; Shastri, Ghanshyam S; Gajera, Mithil J; Judge, Thomas A

2012-05-01

262

Optimisation of in vitro measurement of available iron from different fortificants in citric fruit juices  

Microsoft Academic Search

The percentage of dialyzable ferrous and total iron were studied in a citric juice (pineapple and passion fruit) fortified with ferrous sulphate, micronised dispersible ferric pyrophosphate and ferrous bis-glycinate in similar concentrations (49.2mg Fe\\/l). The in vitro method of Kapsokefalou and Miller (1991) [Kapsokefalou, M., & Miller, D. D. (1991). Effects of meat and selected food components on the valence

J. F. Haro-Vicente; C. Martínez-Graciá; G. Ros

2006-01-01

263

Oxidative activity and dialyzability of some iron compounds under conditions of a simulated gastrointestinal digestion in the presence of phytate  

Microsoft Academic Search

The oxidative activity of some iron compounds was compared under conditions of gastrointestinal digestion and correlated with iron solubility and dialyzability. Ferric chloride, NaFeEDTA, ferrous bis-glycinate, ferrous gluconate, or ferrous lactate, were mixed with water or a phytate solution or a phytate solution treated with phytase and digested in vitro. The dialyzable and the non-dialyzable fractions of the digests were

Maria Kapsokefalou; Vasilis Kakouris; Kyriakos Makris; Maria Galiotou-Panayotou; Michael Komaitis

2007-01-01

264

Copper chelators: chemical properties and bio-medical applications.  

PubMed

Copper is present in different concentrations and chemical forms throughout the earth crust, surface and deep water and even, in trace amounts, in the atmosphere itself. Copper is one of the first metals used by humans, the first artifacts dating back 10,000 years ago. Currently, the world production of refined copper exceeds 16,000 tons/year. Copper is a micro-element essential to life, principally for its red-ox properties that make it a necessary cofactor for many enzymes, like cytochrome-c oxidase and superoxide dismutase. In some animal species (e.g. octopus, snails, spiders, oysters) copper-hemocyanins also act as carriers of oxygen instead of hemoglobin. However, these red-ox properties also make the pair Cu(+)/Cu(2+) a formidable catalyst for the formation of reactive oxygen species, when copper is present in excess in the body or in tissues. The treatment of choice in cases of copper overloading or intoxication is the chelation therapy. Different molecules are already in clinical use as chelators or under study or clinical trial. It is worth noting that chelation therapy has also been suggested to treat some neurodegenerative diseases or cardiovascular disorders. In this review, after a brief description of the homeostasis and some cases of dyshomeostasis of copper, the main (used or potential) chelators are described; their properties in solution, even in relation to the presence of metal or ligand competitors, under physiological conditions, are discussed. The legislation of the most important Western countries, regarding both the use of chelating agents and the limits of copper in foods, drugs and cosmetics, is also outlined. PMID:24934357

Tegoni, M; Valensin, D; Toso, L; Remelli, M

2014-01-01

265

Kinetic and equilibrium constants of phytic acid and ferric and ferrous phytate derived from nuclear magnetic resonance spectroscopy.  

PubMed

Inositol phosphates are metabolically derived organic phosphates (P) that increasingly appear to be an important sink and source of P in the environment. Salts of myo-inositol hexakisdihydrogen phosphate (IHP) or more commonly phytate are the most common inositol phosphates in the environment. IHP resists acidic dephosphorylation and enzymatic dephosphorylation as ferric or ferrous IHP. Mobility of IHP iron complexes is potentially pH and redox responsive, making the time scale and environmental fate and transport of the P associated with the IHP of interest to the mass balance of phosphorus. Ferric and ferrous complexes of IHP were investigated by proton nuclear magnetic resonance spectroscopy ( (1)H NMR) and enzymatic dephosphorylation. Ferrous IHP was found to form quickly and persist for a longer period then ferric IHP. Dissociation constants derived from (1)H NMR experiments of chemically exchanging systems at equilibrium were 1.11 and 1.19 and formation constants were 0.90 and 0.84 for ferric and ferrous IHP, respectively. The recovery of P from enzymatic dephosphorylation of ferric and ferrous IHP was consistent with the magnitude of the kinetic and equilibrium rate constants. PMID:18798632

Heighton, Lynne; Schmidt, Walter F; Siefert, Ronald L

2008-10-22

266

Density functional theory study of an all ferrous 4Fe-4S cluster.  

PubMed

The all-ferrous, carbene-capped Fe(4)S(4) cluster, synthesized by Deng and Holm (DH complex), has been studied with density functional theory (DFT). The geometry of the complex was optimized for several electronic configurations. The lowest energy was obtained for the broken-symmetry (BS) configuration derived from the ferromagnetic state by reversing the spin projection of one of the high spin (S(i) = 2) irons. The optimized geometry of the latter configuration contains one unique and three equivalent iron sites, which are both structurally and electronically clearly distinguishable. For example, a distinctive feature of the unique iron site is the diagonal Fe···S distance, which is 0.3 Å longer than for the equivalent irons. The calculated (57)Fe hyperfine parameters show the same 1:3 pattern as observed in the Mössbauer spectra and are in good agreement with experiment. BS analysis of the exchange interactions in the optimized geometry for the 1:3, M(S) = 4, BS configuration confirms the prediction of an earlier study that the unique site is coupled to the three equivalent ones by strong antiferromagnetic exchange (J > 0 in J ?(j<4)?(4)·?(j)) and that the latter are mutually coupled by ferromagnetic exchange (J' < 0 in J' ?(iferrous cluster of the Fe-protein of nitrogenase, results from a remarkably strong dependence of the exchange interactions on cluster core geometry. The structure dependence of the exchange-coupling constants in the Fe(II)-(?(3)-S)(2)-Fe(II) moieties of the all-ferrous clusters is compared with the magneto-structural correlations observed in the data for dinuclear copper complexes. Finally, we discuss two all-ferric clusters in the light of the results for the all-ferrous cluster. PMID:21476577

Chakrabarti, Mrinmoy; Münck, Eckard; Bominaar, Emile L

2011-05-16

267

Clean ferrous casting technology research. Final technical report, September 29, 1993--December 31, 1995  

SciTech Connect

This is the final report covering work performed on research into methods of attaining clean ferrous castings. In this program methods were developed to minimize the formation of inclusions in steel castings by using a variety of techniques which decreased the tendency for inclusions to form during melting, casting and solidification. In a second project, a reaction chamber was built to remove inclusions from molten steel using electromagnetic force. Finally, a thorough investigation of the causes of sand penetration defects in iron castings was completed, and a program developed which predicts the probability of penetration formation and indicates methods for avoiding it.

Bates, C.E.; Griffin, J.; Giese, S.R.; Lane, A.M. [and others

1996-01-31

268

Friction and surface chemistry of some ferrous-base metallic glasses  

NASA Technical Reports Server (NTRS)

The friction properties of some ferrous-base metallic glasses were measured both in argon and in vacuum to a temperature of 350 C. The alloy surfaces were also analyzed with X-ray photoelectron spectroscopy to identify the compounds and elements present on the surface. The results of the investigation indicate that even when the surfaces of the amorphous alloys, or metallic glasses, are atomically clean, bulk contaminants such as boric oxide and silicon dioxide diffuse to the surfaces. Friction measurements in both argon and vacuum indicate that the alloys exhibit higher coefficients of friction in the crystalline state than they do in the amorphous state.

Miyoshi, K.; Buckley, D. H.

1982-01-01

269

Competitive Inhibition of Ferrous Iron Oxidation by Thiobacillus ferrooxidans by Increasing Concentrations of Cells  

PubMed Central

The oxidation of ferrous iron (Fe2+) to ferric iron (Fe3+) with dioxygen (O2) by various strains of Thiobacillus ferrooxidans was studied by measuring the rate of O2 consumption at various Fe2+ concentrations and cell concentrations. The apparent Km values for Fe2+ remained constant at different cell concentrations of laboratory strains ATCC 13661 and ATCC 19859 but increased with increasing cell concentrations of mine isolates SM-4 and SM-5. The latter results are explained by the competitive inhibition of the Fe2+-binding site of a cell by other cells in the reaction mixture. Possible mechanisms involving cell surface properties are discussed. PMID:16347904

Suzuki, Isamu; Lizama, Hector M.; Tackaberry, Patrick D.

1989-01-01

270

Ferrous Analysis.  

ERIC Educational Resources Information Center

Elements covered in this review include: aluminum, antimony, arsenic, bismuth, boron, calcium, carbon, chromium, cobalt, copper, hydrogen, iron, lead, magnesium, manganese, molybdenum, nickel, niobium, nitrogen, oxygen, phosphorus, platinum, rare earths, silicons, sulfur, tin, titanium, tungsten, vanadium, zinc, and zirconium. Analytical methods…

Straub, William A.

1989-01-01

271

Degradation of trichloroethylene in aqueous solution by calcium peroxide activated with ferrous ion.  

PubMed

The application of calcium peroxide (CaO2) activated with ferrous ion to stimulate the degradation of trichloroethylene (TCE) was investigated. The experimental results showed that TCE could be completely degraded in 5 min at a CaO2/Fe(II)/TCE molar ratio of 4/8/1. Probe compound tests demonstrated the presence of reactive oxygen species HO· and O2(-·) in CaO2/Fe(II) system, while scavenging tests indicated that HO· was the dominant active species responsible for TCE removal, and O2(-·) could promote TCE degradation in CaO2/Fe(II) system. In addition, the influences of initial solution pH and solution matrix were evaluated. It suggested that the elevation of initial solution pH suppressed TCE degradation. Cl(-) had significant scavenging effect on TCE removal, whereas HCO3(-) of high concentration showed favorable function. The influences of NO3(-) and SO4(2-) could be negligible, while natural organic matter (NOM) had a negative effect on TCE removal at a relatively high concentration. The results demonstrated that the technique of CaO2 activated with ferrous ion is a highly promising technique in in situ chemical oxidation (ISCO) remediation in TCE contaminated sites. PMID:25463240

Zhang, Xiang; Gu, Xiaogang; Lu, Shuguang; Miao, Zhouwei; Xu, Minhui; Fu, Xiaori; Qiu, Zhaofu; Sui, Qian

2015-03-01

272

Olfactory ferric and ferrous iron absorption in iron-deficient rats  

PubMed Central

The absorption of metals from the nasal cavity to the blood and the brain initiates an important route of occupational exposures leading to health risks. Divalent metal transporter-1 (DMT1) plays a significant role in the absorption of intranasally instilled manganese, but whether iron uptake would be mediated by the same pathway is unknown. In iron-deficient rats, blood 59Fe levels after intranasal administration of the radioisotope in the ferrous form were significantly higher than those observed for iron-sufficient control rats. Similar results were obtained when ferric iron was instilled intranasally, and blood levels of 59Fe were even greater in the iron-deficient rats compared with the amount of ferrous iron absorbed. Experiments with Belgrade (b/b) rats showed that DMT1 deficiency limited ferric iron uptake from the nasal cavity to the blood compared with +/b controls matched for iron deficiency. These results indicate that olfactory uptake of ferric iron by iron-deficient rats involves DMT1. Western blot experiments confirmed that DMT1 levels are significantly higher in iron-deficient rats compared with iron-sufficient controls in olfactory tissue. Thus the molecular mechanism of olfactory iron absorption is regulated by body iron status and involves DMT1. PMID:22492739

Ruvin Kumara, V. M.

2012-01-01

273

Ettringite-induced heave in chromite ore processing residue (COPR) upon ferrous sulfate treatment.  

PubMed

A pilot-scale treatment study was implemented at a deposition site of chromite ore processing residue (COPR) in New Jersey. Ferrous sulfate heptahydrate (FeSO4 x 7H2O) was employed to reduce hexavalent chromium in two dosages with three types of soil mixing equipment. XANES analyses of treated samples cured for 240 days indicated that all treatment combinations failed to meet the Cr(VI) regulatory limit of 240 mg/kg. More importantly, the discrepancy between XANES and alkaline digestion results renders the latter unreliable for regulatory purposes when applied to ferrous-treated COPR. Regardless of Cr-(VI), the introduction of reductant containing sulfate, mechanical mixing, water, acidity, and the resulting temperature increase in treated COPR promoted dissolution of brownmillerite (Ca2FeAlO5), releasing alumina and alkalinity. The pH increase caused initially precipitated gypsum (CaSO4 x 2H2O) to progressively convert to ettringite (Ca6Al2(SO4)3 x 32H2O) and its associated volume expansion under both in situ and ex situ conditions, with a maximum of 0.8 m vertical swell within 40 days of curing. While Cr-(VI) treatment remains a challenge, the intentional exhaustion of the heave potential of COPR by transforming all Al sources to ettringite emerges as a possible solution to delayed ettringite formation, which would hamper site redevelopment. PMID:17007141

Dermatas, Dimitris; Chrysochoou, Maria; Moon, Deok Hyun; Grubb, Dennis G; Wazne, Mahmoud; Christodoulatos, Christos

2006-09-15

274

Elastic properties of ferrous bearing MgSiO3 and their relevance to ULVZs  

NASA Astrophysics Data System (ADS)

We used ab initio molecular dynamics to calculate the elastic constants of MgSiO3, FeSiO3 and (Fe0.5Mg0.5)SiO3 perovskite under lower-most mantle conditions (136 GPa, 2000-4000 K). At 0 K, Vp and Vs for FeSiO3 perovskite are 12 and 18 per cent lower, respectively than those for MgSiO3, in agreement with previous work. The difference in velocity, however, increases with temperature for high spin (but not low spin) states and at 4000 K, Vp and Vs for the end-member FeSiO3 are, respectively, 19 and 34 per cent lower than those of MgSiO3. We find that (dlnVs/dlnVp)T,P of FexMg1-xO3 remains below 2 for all relevant iron concentrations and lower than the value of 3 seen in most ultralow velocity zones (ULVZ). Moreover, we are unable to match simultaneously the observed density increase and shear wave velocity reduction shown by ULVZs by increasing the ferrous iron content in perovskite except for the largest density increases and the smallest shear wave decreases observed in ULVZs. Assuming that current seismic estimates of ULVZ properties are accurate, our results suggest that ferrous iron enrichment alone cannot explain ULVZs.

Muir, Joshua M. R.; Brodholt, John P.

2015-04-01

275

PARTICIPATION OF A NON-RESPIRATORY FERROUS COMPLEX DURING MITOSIS IN ROOTS  

PubMed Central

A systematic survey was undertaken, of the effects of carbon monoxide and hydrogen cyanide (in the presence of 20 per cent oxygen), in darkness and light, on the relative rates of respiration, mitosis, and interphase in pea root tips. The inhibition of respiration by carbon monoxide was light-sensitive, but the inhibition by hydrogen cyanide was light-stable. The inhibitions were presumably due to combination of the inhibitor with the iron of cytochrome oxidase, in its divalent and trivalent forms respectively. In contrast, the inhibitions of mitosis by both poisons proved to be light-sensitive. The light-sensitive inhibition of mitosis by carbon monoxide shows that an iron complex is responsible for the process. That the inhibition of mitosis by hydrogen cyanide is also light-reversible shows that, in contrast with cytochrome oxidase, the mitotic iron complex remains always in the divalent state. The relative affinities of the mitotic ferrous complex, in molar units, were 0.68 for CO/O2, and 0.37 for HCN/O2. The properties of the complex are analogous to, yet distinct from, Gastrophilus haemoglobin and reduced cytochrome oxidase. It is considered that the arrest of mitosis by oxygen lack, carbon monoxide, and hydrogen cyanide is definitely due to interference with this unidentified, non-respiratory ferrous complex. PMID:13861011

Amoore, J. E.

1962-01-01

276

The photochemical origins of life and photoreaction of ferrous ion in the archaean oceans  

NASA Astrophysics Data System (ADS)

A general argument is made for the photochemical origins of life. A constant flux of free energy is required to maintain the organized state of matter called life. Solar photons are the unique source of the large amounts of energy probably require to initiate this organization and certainly required for the evolution of life to occur. The completion of this argument will require the experimental determination of suitable photochemical reactions. Our work shows that biogenetic porphyrins readily photooxidize substrates and emit hydrogen in the presence of a catalyst. These results are consistent with the Granick hypothesis, which relates a biosynthetic pathway to its evolutionary origin. We have shown that photoexcitation of ferrous ion at neutral pH with near ultraviolet light produces hydrogen with high quantum yield. This same simple system may reduce carbon dioxide to formaldehyde and further products. These reactions offer a solution to the dilemma confronting the Oparin-Urey-Miller model of the chemical origin of life. If carbon dioxide is the main form of carbon on the primitive earth, the ferrous photoreaction may provide the reduced carbon necessary for the formation of amino acids and other biogenic molecules. These results suggest that this progenitor of modern photosynthesis may have contributed to the chemical origins of life.

Mauzerall, David C.

1990-05-01

277

Efficient near ultraviolet light induced formation of hydrogen by ferrous hydroxide  

NASA Astrophysics Data System (ADS)

A possible origin of early hydrogen by UV-induced photoreduction of ferrous ions was investigated by measuring the rate of H2 formation from irradiated FeSO4 solutions as a function of pH and the range of UV sources. It was found that, in addition to the known reaction in acid solution which decreases in yield with increasing pH and requires far-UV light, there is an efficient reaction occurring between pH 6 and 9 which utilizes near-UV light (of a 200-W mercury arc lamp). This latter reaction is a linear function of both the concentration of Fe(2+) and the light intensity. These results support the suggestion of Braterman et al. (1983) that the near-UV-driven photooxidation of ferrous ions may be responsible for the origin of the banded iron formations on the early earth. The efficient photoreaction could also explain the source of reducing equivalents for CO2 reduction.

Borowska, Zofia K.; Mauzerall, David C.

1987-09-01

278

Efficient near ultraviolet light induced formation of hydrogen by ferrous hydroxide. [in primitive earth  

NASA Technical Reports Server (NTRS)

A possible origin of early hydrogen by UV-induced photoreduction of ferrous ions was investigated by measuring the rate of H2 formation from irradiated FeSO4 solutions as a function of pH and the range of UV sources. It was found that, in addition to the known reaction in acid solution which decreases in yield with increasing pH and requires far-UV light, there is an efficient reaction occurring between pH 6 and 9 which utilizes near-UV light (of a 200-W mercury arc lamp). This latter reaction is a linear function of both the concentration of Fe(2+) and the light intensity. These results support the suggestion of Braterman et al. (1983) that the near-UV-driven photooxidation of ferrous ions may be responsible for the origin of the banded iron formations on the early earth. The efficient photoreaction could also explain the source of reducing equivalents for CO2 reduction.

Borowska, Zofia K.; Mauzerall, David C.

1987-01-01

279

Prospects for Ukrainian ferrous metals in the post-soviet period  

USGS Publications Warehouse

Two specialists on the mineral industries of the countries of the former USSR survey current problems confronting producers of ferrous metals in Ukraine and future prospects for domestic production and exports. A series of observations documenting the importance of ferrous metals production to Ukraine's economy is followed by sections describing investment plans and needs in the sector, and the role played by Ukraine within the iron and steel industry of the Soviet Union. The focus then turns to assessment of the current regional and global competitive position of Ukrainian producers for each of the major commodities of the sector-iron ore, manganese ore, ferroalloys, steel, and the products of the machine manufacturing and metal working industries. In conclusion, the paper discusses a potential regional industrial integration strategy analogous to that employed in the United States' Great Lakes/Midwest region, which possesses similar types of iron ore deposits and similar transport cost advantages and metallurgical and manufacturing industries. Journal of Economic Literature, Classification Numbers: F14, L61, L72. 1 table, 26 references.

Levine, R.M.; Bond, A.R.

1998-01-01

280

Expression, purification and functional reconstitution of FeoB, the ferrous iron transporter from Pseudomonas aeruginosa.  

PubMed

The FeoB Fe(II) transporter from the drug resistant pathogen, Pseudomonas aeruginosa is essential for ferrous iron transport and is implicated in virulence and biofilm development. Hence it is an attractive target for the development of new anti-infective drugs. FeoB is an intriguing protein that consists of a cytosolic N-terminal GTPase domain and an integral membrane domain which most likely acts as ferrous iron permease. Characterisation of FeoB is critical for developing therapeutics aimed at inhibiting this protein. However, structural and functional analysis of FeoB is hampered by the lack of high yield homogenously pure protein which is monodisperse, stable and active in solution. Here we describe the optimised procedure for the recombinant expression of FeoB from P. aeruginosa and provide an evaluation of the most favourable purification, pH and detergent conditions. The functional reconstitution of FeoB in liposomes is also described. This represents the first detailed procedure for obtaining a pure, active and stable FeoB solution in milligram quantities which would be amenable to biochemical, biophysical and structural studies. PMID:24993789

Seyedmohammad, Saeed; Born, Diana; Venter, Henrietta

2014-09-01

281

Absorption of iron polymaltose and ferrous sulphate in rats and humans. A comparative study.  

PubMed

Free iron in the circulation in contrast to iron complexed with protein or carbohyrdate, is intensely toxic. The annual morbidity and mortality from accidental overdose with iron salts is significant and has directed attention to the evaluation of safer forms of therapy. Comparative studies between oral ferrous sulphate and iron polymaltose in rats established an LD100 of 350 mg/kg for the salt, whereas neither morbidity nor mortality could be produced in doses exceeding 1 000 mg/kg for the complex. Bio-availability of iron from salt and complex for haemoglobin synthesis was then compared both in rats and in man with a twin-isotope technique. In experimental animals and in the human studies, venesected individuals were used to reproduce the iron deficiency state where treatment would be indicated. It was concluded that bioavailability is comparable for therapeutic doses of ferrous sulphate and iron polymaltose in iron-deficient subjects. The marginally lower absorption of complex was offset by a greater degree of gastrointestinal tract tolerance; the wide margin of safety may be of importance in reducing the danger of accidental iron overdose. PMID:472964

Jacobs, P; Wormald, L A; Gregory, M C

1979-06-23

282

The photochemical origins of life and photoreaction of ferrous ion in the archaean oceans  

NASA Technical Reports Server (NTRS)

A general argument is made for the photochemical origins of life. A constant flux of free energy is required to maintain the organized state of matter called life. Solar photons are the unique source of the large amounts of energy probably required to initiate this organization and certainly required for the evolution of life to occur. The completion of this argument will require the experimental determination of suitable photochemical reactions. It is shown that biogenetic porphyrins readily photooxidize substrates and emit hydrogen in the presence of a catalyst. These results are consistent with the Granick hypothesis, which relates a biosynthetic pathway to its evolutionary origin. It has been shown that photoexcitation of ferrous ion at neutral pH with near ultraviolet light produces hydrogen with high quantum yield. This same simple system may reduce carbon dioxide to formaldehyde and further products. These reactions offer a solution to the dilemma confronting the Oparin-Urey-Miller model of the chemical origin of life. If carbon dioxide is the main form of carbon on the primitive earth, the ferrous photoreaction may provide the reduced carbon necessary for the formation of amino acids and other biogenic molecules. These results suggest that this progenitor of modern photosynthesis may have contributed to the chemical origins of life.

Mauzerall, David C.

1990-01-01

283

Binuclear Copper(II) Chelates of Amide-Based Cyclophanes.  

PubMed

A chelating cyclophane has been synthesized by cyclocondensation of two ethylenediaminetetraacetic (EDTA) units with two p-phenylenediamine units: the resulting cyclophane is 2,9,18,25-tetraoxo-4,7,20,23-tetrakis(carboxymethyl)-1,4,7,10,17,20,23,26-octaaza[10.10]paracyclophane, abbreviated as (bis-edtapdn)H(4). Cyclocondensation of two EDTA and two 1,5-diaminonaphthalene units has given the naphthalenophane, 2,9,22,29-tetraoxo-4,7,24,27-tetrakis(carboxymethyl)-1,4,7,10,21,24,27,30-octaaza[10.10](1,5)naphthalenophane, (bis-edtanap)H(4). Studies of electronic and EPR spectra have been carried out on the binuclear Cu(2+) complexes of these new ligands and of related chelating cyclophanes, 2,9,25,32-tetraoxo-4,7,27,30-tetrakis(carboxymethyl)-1,4,7,10,24,27,30,33-octaaza[10.1.10.1]paracyclophane, abbreviated as (bis-edtabpm)H(4), and 2,9,25,32-tetraoxo-4,7,27,30-tetrakis(carboxymethyl)-1,4,7,10,24,27,30,33-octaaza-17,40-dioxa[10.1.10.1]paracyclophane, abbreviated as (bis-edtabpe)H(4). Common features of these chelating cyclophanes are as follows: (1) amino, amide, and pendant carboxymethyl donor groups are substituents in the cyclophane ring, and (2) the amide groups are directly bound to the aromatic groups. These ligands formed neutral binuclear Cu(2+) chelates [Cu(2)L](0) that are water-insoluble. In alkaline solutions, these Cu(2+) complexes were converted to anionic chelates [Cu(2)(LH(-)(4))](4)(-) in which deprotonated amide nitrogens coordinated Cu(2+) ions. These anionic metal chelates of (bis-edtapdn)H(4), (bis-edtabpm)H(4), and (bis-edtabpe)H(4) exhibited three pi-pi transition bands in the spectral range 240-340 nm, in contrast to the uncoordinated cyclophanes, which showed a single band in this spectral range. The unusual pi-pi transition spectra of the [Cu(2)(LH(-)(4))](4)(-) complexes originate from the combined effect of metal-ligand charge transfer and proximity of the pi systems. The absorption and emission spectra of (bis-edtanap)H(4) were also influenced by coordination with copper. The EPR spectrum of [Cu(2)(bis-edtanapH(-)(4))](4)(-) in a methanol glass matrix showed a hyperfine structure due to the spin exchange between two Cu(2+) ions. These unusual spectral and magnetic properties arise from the strong coordination between Cu(2+) ions and deprotonated amide nitrogens that are bound to the pi systems. PMID:11670526

Inoue, Michiko B.; Velazquez, Enrique F.; Medrano, Felipe; Ochoa, Karen L.; Galvez, J. C.; Inoue, Motomichi; Fernando, Quintus

1998-08-10

284

Fractionation and identification of Alaska pollock skin collagen-derived mineral chelating peptides.  

PubMed

Peptides with the ability to chelate dietary minerals have been reported to have potential as functional food ingredients. A collagen tryptic hydrolysate (CTH), previously shown to chelate iron, was further investigated for the presence of Ca, Fe and Cu chelating peptides. Sequential purification steps, including immobilised metal affinity chromatography (IMAC) and gel permeation chromatography (GPC) were employed for the separation of chelating peptides. GPC analysis showed that the mineral chelating peptides were mainly between 500 and 2000 Da. Subsequent identification was carried out using UPLC-ESI-QTOF MS/MS. Overall, 10 sequences were identified as potential chelating peptides. The Ca, Fe and Cu chelating activity of GPAGPHGPPG was 11.52±2.23 nmol/?mol, 1.71±0.17 nmol/?mol and 0.43±0.02 ?mol/?mol, respectively. This study identifies collagen as a good source of peptides with potential applications as functional ingredients in the management of mineral deficiencies. PMID:25466056

Guo, Lidong; Harnedy, Pádraigín A; O'Keeffe, Martina B; Zhang, Li; Li, Bafang; Hou, Hu; FitzGerald, Richard J

2015-04-15

285

Erythrocytes: Better Tolerance of Iron Polymaltose Complex Compared with Ferrous Sulphate in the Treatment of Anaemia.  

PubMed

BackgroundAbsolute iron deficiency, irrespective of aetiology, remains a major and worldwide cause of morbidity. After correction of the causative lesion, reconstitution of haemoglobin level and body iron stores is traditionally achieved with oral administration of ferrous salts. The latter have significant gastrointestinal tract side-effects that, in the short-term, may impair compliance. With protracted administration these products can cause lipid peroxidation which, in turn, may accelerate atherogenesis. An alternative formulation is an iron polymaltose complex where animal data supported a promoting effect of glycerophosphate. Setting and Trial Design This was a single-centre, open, randomised, multidose four treatment parallel group study. A standard dose of ferric polymaltose complex with two differing levels of glycerophosphate was compared with an equivalent amount of iron supplied as ferrous sulphate in anaemic volunteer blood donors. The endpoints were rate of haemoglobin rise and re-expansion of body iron stores reflected in blood ferritin concentration, as well as percentage saturation of transferrin. Secondary observations were changes in the proportion of hypochromic red cells during the course of treatment, erythropoietin levels and tolerability of the two formulations. Results Outcome in the rat model suggested that the utilisation of iron from polymaltose might be enhanced by glycerophosphate. However, in donors this difference was not evident and, accordingly, the data from the three polymaltose groups combined and compared to those receiving ferrous sulphate. The rate at which haemoglobin level improved, red cell indices returned to normal, and the number of hypochromic and microcytic red cells fell was not significantly different between the groups. Similarly the serum iron, percentage saturation of transferrin and red cell ferritin were comparable. In contrast the serum ferritin levels were higher for those receiving ferrous sulphate. Additionally, side-effects were significantly more frequently encountered with the latter preparation. Conclusion These data demonstrate that the addition of glycerophosphate, observed to be beneficial in rats, did not occur in humans. Secondly, in the blood donors, equivalent amounts of iron provided as the polymaltose, with or without glycerophosphate or ferrous sulphate, corrected haemoglobin concentration and morphologically abnormal erythropoiesis at comparable rates. Similarly iron stores are replenished to an equivalent extent as seen in the matching percentage saturation of transferrin and red cell ferritin levels. Interestingly, there is a discrepancy in the serum ferritin which is higher with the salt and this may reflect oxidative stress. Thirdly, corresponding efficacy can be achieved with better patient tolerance for the complex. Finally it is postulated that the iron polymaltose complex formulation more closely approximates the way in which enterocytes handle dietary iron and thus physiologic regulatory mechanisms would be expected to reciprocally slow down absorption as stores expand. Logically, therefore and, if confirmed, the latter finding suggests that this formulation may have a potential role in longer-term supplementation programmes. PMID:11399604

Jacobs, PETER; Wood, LUCILLE; Bird, ARTHUR R.

2000-01-01

286

TREATMENT OF HEXAVALENT CHROMIUM IN CHROMITE ORE PROCESSING SOLID WASTE USING A MIXED REDUCTANT SOLUTION OF FERROUS SULFATE AND SODIUM DITHIONITE  

EPA Science Inventory

We developed a method for disseminating ferrous iron in the subsurface to enhance chemical reduction of hexavalent chromium (Cr(VI)) in a chromite ore processing solid waste derived from the production of ferrochrome alloy. The method utilizes ferrous sulfate (FeSO4) in combinati...

287

FERROUS METALS RECOVERY AT RECOVERY 1, NEW ORLEANS: PERFORMANCE OF THE MODIFIED SYSTEM. TEST NO. 4.05 AND TEST NO. 4.09, RECOVERY 1, NEW ORLEANS  

EPA Science Inventory

This report documents two series of samplings and the monitoring of enery consumption and shredder hammer wear of the upgraded ferrous recovery system that produces a light ferrous product from the processing of municipal refuse at the New Orleans resource recovery project. A ser...

288

Lanthanides caged by the organic chelates; structural properties  

NASA Astrophysics Data System (ADS)

The structure, in particular symmetry, geometry and morphology of organic chelates coordinated with the lanthanide ions are analyzed in the present review. This is the first part of a complete presentation of a theoretical description of the properties of systems, which are widely used in technology, but most of all, in molecular biology and medicine. The discussion is focused on the symmetry and geometry of the cages, since these features play a dominant role in the spectroscopic activity of the lanthanides caged by organic chelates. At the same time, the spectroscopic properties require more formal presentation in the language of Racah algebra, and deserve a separate analysis. In addition to the parent systems of DOTA, DOTP, EDTMP and CDTMP presented here, their modifications by various antennas are analyzed. The conclusions that have a strong impact upon the theory of the energy transfer and the sensitized luminescence of these systems are based on the results of numerical density functional theory calculations.

Smentek, Lidia

2011-04-01

289

Improved paramagnetic chelate for molecular imaging with MRI  

NASA Astrophysics Data System (ADS)

The relaxivity and transmetallation of two lipophilic paramagnetic chelates incorporated onto perfluorocarbon nanoparticles, i.e., gadolinium-methoxy-tetraazacyclododecane-tetraacetic acid phosphatidylethanolamine (Gd-MeO-DOTA-PE) and gadolinium-methoxy-tetraazacyclododecane-tetraacetic acid triglycine phosphatidylethanolamine (Gd-MeO-DOTA-triglycine-PE (Gd-MeO-DOTA-triglycine-PE)), were compared to a prototypic gadolinium-diethylene-triamine-pentaacetic acid bis-oleate (Gd-DTPA-BOA) paramagnetic formulation. Nanoparticles with MeO-DOTA-based chelates demonstrated higher relaxivity (40% higher for Gd-MeO-DOTA-PE and 55% higher for Gd-MeO-DOTA-triglycine-PE) and less transmetallation than the original Gd-DTPA-BOA-based agent.

Winter, Patrick; Athey, Phillip; Kiefer, Garry; Gulyas, Gyongyi; Frank, Keith; Fuhrhop, Ralph; Robertson, David; Wickline, Samuel; Lanza, Gregory

2005-05-01

290

Removal of cadmium from fish sauce using chelate resin.  

PubMed

Fish sauce that is prepared from squid organs contains cadmium (Cd), which may be present at hazardous concentrations. Cd molecules are predominantly protein bound in freshly manufactured fish sauce, but are present in a liberated form in air-exposed fish sauce. In the present study, we developed a new method for removing both Cd forms from fish sauce using chelate resin and a previously reported tannin treatment. Sixteen-fold decreases in Cd concentrations were observed (0.78-0.05 mg/100 mL) following the removal of liberated Cd using chelate resin treatment, and the removal of protein-bound Cd using tannin treatment. Major nutritional components of fish sauce were maintained, including free amino acids and peptides, and angiotensin I-converting enzyme inhibitory and antioxidant activities. PMID:25466035

Sasaki, Tetsuya; Araki, Ryohei; Michihata, Toshihide; Kozawa, Miyuki; Tokuda, Koji; Koyanagi, Takashi; Enomoto, Toshiki

2015-04-15

291

A novel antimycobacterial compound acts as an intracellular iron chelator.  

PubMed

Efficient iron acquisition is crucial for the pathogenesis of Mycobacterium tuberculosis. Mycobacterial iron uptake and metabolism are therefore attractive targets for antitubercular drug development. Resistance mutations against a novel pyrazolopyrimidinone compound (PZP) that is active against M. tuberculosis have been identified within the gene cluster encoding the ESX-3 type VII secretion system. ESX-3 is required for mycobacterial iron acquisition through the mycobactin siderophore pathway, which could indicate that PZP restricts mycobacterial growth by targeting ESX-3 and thus iron uptake. Surprisingly, we show that ESX-3 is not the cellular target of the compound. We demonstrate that PZP indeed targets iron metabolism; however, we found that instead of inhibiting uptake of iron, PZP acts as an iron chelator, and we present evidence that the compound restricts mycobacterial growth by chelating intrabacterial iron. Thus, we have unraveled the unexpected mechanism of a novel antimycobacterial compound. PMID:25645825

Dragset, Marte S; Poce, Giovanna; Alfonso, Salvatore; Padilla-Benavides, Teresita; Ioerger, Thomas R; Kaneko, Takushi; Sacchettini, James C; Biava, Mariangela; Parish, Tanya; Argüello, José M; Steigedal, Magnus; Rubin, Eric J

2015-04-01

292

MULTIDENTATE TEREPHTHALAMIDATE AND HYDROXYPYRIDONATE LIGANDS: TOWARDS NEW ORALLY ACTIVE CHELATORS  

SciTech Connect

The limitations of current therapies for the treatment of iron overload or radioisotope contamination have stimulated efforts to develop new orally bioavailable iron and actinide chelators. Siderophore-inspired tetradentate, hexadentate and octadentate terephthalamidate and hydroxypyridonate ligands were evaluated in vivo as selective and efficacious iron or actinide chelating agents, with several metal loading and ligand assessment procedures, using {sup 59}Fe, {sup 238}Pu, and {sup 241}Am as radioactive tracers. The compounds presented in this study were compared to commercially available therapeutic sequestering agents [deferoxamine (DFO) for iron and diethylenetriaminepentaacetic acid (DPTA) for actinides] and are unrivaled in terms of affinity, selectivity and decorporation efficacy, which attests to the fact that high metal affinity may overcome the low bioavailability properties commonly associated to multidenticity.

Abergel, Rebecca J.; Raymond, Kenneth N.

2011-07-13

293

Nanomagnetic chelators for removal of toxic metal ions  

NASA Astrophysics Data System (ADS)

Ethylenediamine trtraaceteic acid (EDTA) functionalized Fe3O4 nanomagnetic chelators (NMCs) were synthesized by co-precipitation method followed by in-situ grafting of EDTA. XRD and TEM analyses reveal the formation of highly crystalline single-phase Fe3O4 nanoparticles of size about 10 nm. Surface functionalization of Fe3O4 with EDTA was evident from FTIR spectroscopy, TGA analysis and zeta-potential measurement. These NMCs exhibit superparamagnetic behavior at room temperature with strong field dependent magnetic responsivity. It has been observed that NMCs have strong tendency for adsorption of various toxic metal ions (Ni2+, Cr3+, Cu2+, Cd2+, Co2+ and Pb2+) from waste-water. Furthermore, these magnetic chelators can be used as highly efficient separable and reusable material for removal of toxic metal ions.

Singh, Sarika; Barick, K. C.; Bahadur, D.

2013-02-01

294

Chelating compounds as potential flash rust inhibitors and melamine & aziridine cure of acrylic colloidal unimolecular polymers (CUPs)  

NASA Astrophysics Data System (ADS)

Waterborne coatings on ferrous substrates usually show flash rusting which decreases the adhesion of the coating and the corrosion products can form a stain. Chelating compounds were investigated as potential flash rust inhibitors. Compounds being evaluated include amine alcohols, diamines and sulfur containing amines. A new corrosion inhibitor 2,5-bis(thioaceticacid)-1,3,4-thiadiazole (H2ADTZ) was synthesized and its performance characteristics were evaluated. It was noted that the observed structure of 1,3,4-thiadiazolidine-2,5-dithione (also known as 2,5-dimercapto-1,3,4-thiadiazole (DMTD or DMcT)) has been previously reported in three different tautomeric forms including -dithiol and -dithione. The relative stability of each form as well as the synthesis and characterization of the structures of mono- and dialkylated forms of 5-mercapto-1,3,4-thiadiazole-2(3H)-thione (MTT) were examined. The methods of X-ray crystallography, NMR spectroscopy and ab-initio electronic structure calculations were combined to understand the reactivity and structure of each compound. Polymers were synthesized with a 1:7 or 1:8 ratio of acrylic acid to acrylate monomers to produce an acid rich resin. The polymers were reduced and solvent stripped to produce Colloidal Unimolecular Polymers (CUPs). These particles are typically 3-9 nanometers in diameter depending upon the molecular weight. They were then formulated into a clear coating with either a melamine (bake) or an aziridine (ambient cure) and then cured. The melamine system was solvent free, a near zero VOC and the aziridine system was very low to near zero VOC. The coatings were evaluated for their MEK resistance, adhesion, hardness, gloss, flexibility, wet adhesion, abrasion and impact resistance properties.

Mistry, Jigar Kishorkumar

295

Comparing potential copper chelation mechanisms in Parkinson's disease protein  

Microsoft Academic Search

We have implemented the nudged elastic band (NEB) as a guided dynamics framework for our real-space multigrid method of DFT-based quantum simulations. This highly parallel approach resolves a minimum energy pathway (MEP) on the energy hypersurface by relaxing intermediates in a chain-of-states. As an initial application we present an investigation of chelating agents acting on copper ion bound to alpha-synuclein,

Frisco Rose; Miroslav Hodak; Jerry Bernholc

2011-01-01

296

Targeting Chelatable Iron as a Therapeutic Modality in Parkinson's Disease  

PubMed Central

Abstract Aims: The pathophysiological role of iron in Parkinson's disease (PD) was assessed by a chelation strategy aimed at reducing oxidative damage associated with regional iron deposition without affecting circulating metals. Translational cell and animal models provided concept proofs and a delayed-start (DS) treatment paradigm, the basis for preliminary clinical assessments. Results: For translational studies, we assessed the effect of oxidative insults in mice systemically prechelated with deferiprone (DFP) by following motor functions, striatal dopamine (HPLC and MRI-PET), and brain iron deposition (relaxation-R2*-MRI) aided by spectroscopic measurements of neuronal labile iron (with fluorescence-sensitive iron sensors) and oxidative damage by markers of protein, lipid, and DNA modification. DFP significantly reduced labile iron and biological damage in oxidation-stressed cells and animals, improving motor functions while raising striatal dopamine. For a pilot, double-blind, placebo-controlled randomized clinical trial, early-stage Parkinson's patients on stabilized dopamine regimens enrolled in a 12-month single-center study with DFP (30?mg/kg/day). Based on a 6-month DS paradigm, early-start patients (n=19) compared to DS patients (n=18) (37/40 completed) responded significantly earlier and sustainably to treatment in both substantia nigra iron deposits (R2* MRI) and Unified Parkinson's Disease Rating Scale motor indicators of disease progression (p<0.03 and p<0.04, respectively). Apart from three rapidly resolved neutropenia cases, safety was maintained throughout the trial. Innovation: A moderate iron chelation regimen that avoids changes in systemic iron levels may constitute a novel therapeutic modality for PD. Conclusions: The therapeutic features of a chelation modality established in translational models and in pilot clinical trials warrant comprehensive evaluation of symptomatic and/or disease-modifying potential of chelation in PD. Antioxid. Redox Signal. 21, 195–210. PMID:24251381

Moreau, Caroline; Devedjian, Jean Christophe; Kluza, Jérome; Petrault, Maud; Laloux, Charlotte; Jonneaux, Aurélie; Ryckewaert, Gilles; Garçon, Guillaume; Rouaix, Nathalie; Duhamel, Alain; Jissendi, Patrice; Dujardin, Kathy; Auger, Florent; Ravasi, Laura; Hopes, Lucie; Grolez, Guillaume; Firdaus, Wance; Sablonnière, Bernard; Strubi-Vuillaume, Isabelle; Zahr, Noel; Destée, Alain; Corvol, Jean-Christophe; Pöltl, Dominik; Leist, Marcel; Rose, Christian; Defebvre, Luc; Marchetti, Philippe; Cabantchik, Z. Ioav; Bordet, Régis

2014-01-01

297

EFFECT OF TEMPERATURE ON THE SORPTION OF CHELATED RADIONUCLIDES.  

USGS Publications Warehouse

Temperature effects in the near-field radioactive waste disposal environment can result in changes in the adsorptive capacity and character of the substrate and the chemistry of the reacting fluids. This work examines the effect of temperature on 1) the kinetics of radionuclide sorption onto clays from 25 degree -75 degree C and 2) the degradation and metal-binding ability of two organic complexing agents found in chelated radioactive wastes and natural groundwaters.

Maest, Ann S.; Crerar, David A.; Dillon, Edward C.; Trehu, Stephen M.; Rountree, Tamara N.

1985-01-01

298

Flue gas desulfurization/denitrification using metal-chelate additives  

DOEpatents

A method of simultaneously removing SO/sub 2/ and NO from oxygen-containing flue gases resulting from the combustion of carbonaceous material by contacting the flue gas with an aqueous scrubber solution containing an aqueous sulfur dioxide sorbent and an active metal chelating agent which promotes a reaction between dissolved SO/sub 2/ and dissolved NO to form hydroxylamine N-sulfonates. The hydroxylamine sulfonates are then separated from the scrubber solution which is recycled. 3 figs.

Harkness, J.B.L.; Doctor, R.D.; Wingender, R.J.

1985-08-05

299

Flue gas desulfurization/denitrification using metal-chelate additives  

DOEpatents

A method of simultaneously removing SO.sub.2 and NO from oxygen-containing flue gases resulting from the combustion of carbonaceous material by contacting the flue gas with an aqueous scrubber solution containing an aqueous sulfur dioxide sorbent and an active metal chelating agent which promotes a reaction between dissolved SO.sub.2 and dissolved NO to form hydroxylamine N-sulfonates. The hydroxylamine sulfonates are then separated from the scrubber solution which is recycled.

Harkness, John B. L. (Naperville, IL); Doctor, Richard D. (Glen Ellyn, IL); Wingender, Ronald J. (Deerfield, IL)

1986-01-01

300

Chelate-Enhanced Phytoremediation of Soils Polluted with Heavy Metals  

Microsoft Academic Search

In general, hyperaccumulators are low biomass, slow-growing plants. High biomass non-hyperaccumulator plants by themselves are not a valid alternative for phytoextraction as they also have many limitations, such as small root uptake and little root-to-shoot translocation. In this context, chemically-induced phytoextraction (based on the fact that the application of certain chemicals, mostly chelating agents, to the soil significantly enhances metal

I. Alkorta; J. Hernández-Allica; J. M. Becerril; I. Amezaga; I. Albizu; M. Onaindia; C. Garbisu

2004-01-01

301

Amelioration of aluminum toxicity to sorghum seedlings by chelating agents  

Microsoft Academic Search

At the pH levels found in acid soils (4.5 to 5.5), theoretical equilibrium models predict that Al will be complexed on a nearly one to one molar basis by NTA, EGTA. oxalate (OX) and citrate (CIT). Growth chamber experiments were initiated using solutions containing Al (0, 2, or 10 ?M), Ca (400 ?.M). and a chelate (0 or 10 ?M)

L. M. Shuman; D. O. Wilson; E. L. Ramseur

1991-01-01

302

Bipyridine, an iron chelator, does not lessen intracerebral iron-induced damage or improve outcome after intracerebral hemorrhagic stroke in rats.  

PubMed

Iron chelators, such as the intracellular ferrous chelator 2,2'-bipyridine, are a potential means of ameliorating iron-induced injury after intracerebral hemorrhage (ICH). We evaluated bipyridine against the collagenase and whole-blood ICH models and a simplified model of iron-induced damage involving a striatal injection of FeCl2 in adult rats. First, we assessed whether bipyridine (25 mg/kg beginning 12 h post-ICH and every 12 h for 3 days) would attenuate non-heme iron levels in the brain and lessen behavioral impairments (neurological deficit scale, corner turn test, and horizontal ladder) 7 days after collagenase-induced ICH. Second, we evaluated bipyridine (20 mg/kg beginning 6 h post-ICH and then every 24 h) on edema 3 days after collagenase infusion. Body temperature was continually recorded in a subset of these rats beginning 24 h prior to ICH until euthanasia. Third, bipyridine was administered (as per experiment 2) after whole-blood infusion to examine tissue loss, neuronal degeneration, and behavioral impairments at 7 days post-stroke, as well as body temperature for 3 days post-stroke. Finally, we evaluated whether bipyridine (25 mg/kg given 2 h prior to surgery and then every 12 h for 3 days) lessens tissue loss, neuronal death, and behavioral deficits after striatal FeCl2 injection. Bipyridine caused a significant hypothermic effect (maximum drop to 34.6 °C for 2-5 h after each injection) in both ICH models; however, in all experiments bipyridine-treated rats were indistinguishable from vehicle controls on all other measures (e.g., tissue loss, behavioral impairments, etc.). These results do not support the use of bipyridine against ICH. PMID:24323426

Caliaperumal, Jayalakshmi; Wowk, Shannon; Jones, Sarah; Ma, Yonglie; Colbourne, Frederick

2013-12-01

303

Mercury removal in utility wet scrubber using a chelating agent  

DOEpatents

A method for capturing and reducing the mercury content of an industrial flue gas such as that produced in the combustion of a fossil fuel or solid waste adds a chelating agent, such as ethylenediaminetetraacetic acid (EDTA) or other similar compounds like HEDTA, DTPA and/or NTA, to the flue gas being scrubbed in a wet scrubber used in the industrial process. The chelating agent prevents the reduction of oxidized mercury to elemental mercury, thereby increasing the mercury removal efficiency of the wet scrubber. Exemplary tests on inlet and outlet mercury concentration in an industrial flue gas were performed without and with EDTA addition. Without EDTA, mercury removal totaled 42%. With EDTA, mercury removal increased to 71%. The invention may be readily adapted to known wet scrubber systems and it specifically provides for the removal of unwanted mercury both by supplying S.sup.2- ions to convert Hg.sup.2+ ions into mercuric sulfide (HgS) and by supplying a chelating agent to sequester other ions, including but not limited to Fe.sup.2+ ions, which could otherwise induce the unwanted reduction of Hg.sup.2+ to the form, Hg.sup.0.

Amrhein, Gerald T. (Louisville, OH)

2001-01-01

304

Regeneration of the heart in diabetes by selective copper chelation.  

PubMed

Heart disease is the major cause of death in diabetes, a disorder characterized by chronic hyperglycemia and cardiovascular complications. Although altered systemic regulation of transition metals in diabetes has been the subject of previous investigation, it is not known whether changed transition metal metabolism results in heart disease in common forms of diabetes and whether metal chelation can reverse the condition. We found that administration of the Cu-selective transition metal chelator trientine to rats with streptozotocin-induced diabetes caused increased urinary Cu excretion compared with matched controls. A Cu(II)-trientine complex was demonstrated in the urine of treated rats. In diabetic animals with established heart failure, we show here for the first time that 7 weeks of oral trientine therapy significantly alleviated heart failure without lowering blood glucose, substantially improved cardiomyocyte structure, and reversed elevations in left ventricular collagen and beta(1) integrin. Oral trientine treatment also caused elevated Cu excretion in humans with type 2 diabetes, in whom 6 months of treatment caused elevated left ventricular mass to decline significantly toward normal. These data implicate accumulation of elevated loosely bound Cu in the mechanism of cardiac damage in diabetes and support the use of selective Cu chelation in the treatment of this condition. PMID:15331567

Cooper, Garth J S; Phillips, Anthony R J; Choong, Soon Y; Leonard, Bridget L; Crossman, David J; Brunton, Dianne H; Saafi, 'Etuate L; Dissanayake, Ajith M; Cowan, Brett R; Young, Alistair A; Occleshaw, Christopher J; Chan, Yih-Kai; Leahy, Fiona E; Keogh, Geraldine F; Gamble, Gregory D; Allen, Grant R; Pope, Adèle J; Boyd, Peter D W; Poppitt, Sally D; Borg, Thomas K; Doughty, Robert N; Baker, John R

2004-09-01

305

Characterization of Two Different 5-Coordinate Soluble Guanylate Cyclase Ferrous Nitrosyl Complexes †  

PubMed Central

Soluble guanylate cyclase (sGC), a hemoprotein, is the primary nitric oxide (NO) receptor in higher eukaryotes. The binding of NO to sGC leads to the formation of a 5-coordinate ferrous-nitrosyl complex, and a several hundred-fold increase in cGMP synthesis. NO activation of sGC is influenced by GTP and the allosteric activators YC-1 and BAY 41-2272. Electron paramagnetic resonance (EPR) spectroscopy shows that the spectrum of the sGC ferrous-nitrosyl complex shifts in the presence of YC-1, BAY 41-2272, or GTP in the presence of excess NO relative to the heme. These molecules shift the EPR signal from one characterized by g1 = 2.083, g2 = 2.036, g3 = 2.012 to a signal characterized by g1 = 2.106, g2 = 2.029, g3 = 2.010. The truncated heme domain constructs ?1(1-194) and ?2(1-217) were compared to the full-length enzyme. The EPR spectrum of the ?2(1-217)-NO complex is characterized by g1 = 2.106, g2 = 2.025, g3 = 2.010 indicating the protein is a good model for the sGC-NO complex in the presence of the activators, while the ?1(1-194)-NO complex resembles the EPR spectrum of sGC in the absence of the activators. Low-temperature resonance Raman spectra of the ?1(1-194)-NO and ?2(1-217)-NO complexes show that the Fe-NO stretching vibration of the ?2(1-217)-NO complex (535 cm?1) is significantly different than that of the ?1(1-194)-NO complex (527 cm?1). This shows that sGC can adopt different 5-coordinate ferrous nitrosyl conformations, and suggests that the Fe-NO conformation characterized by this unique EPR signal and Fe-NO stretching vibration represents a highly active sGC state. PMID:18302323

Derbyshire, Emily R.; Gunn, Alexander; Ibrahim, Mohammed; Spiro, Thomas G.; Britt, R. David; Marletta, Michael A.

2009-01-01

306

Ferrous iron phosphorus in sediments: development of a quantification method through 2,2'-bipyridine extraction.  

PubMed

The role of ferrous iron in the phosphorus cycle of an aquatic ecosystem is poorly understood because of a lack of suitable methods to quantitatively evaluate ferrous iron phosphorus (FIP) phases. Using sediments sampled from Fubao Bay of Dianchi Lake in China, a novel extraction method for FIP using 2,2'-bipyridine was explored. Total phosphorus and iron in the sediments ranged from 1.0 to 5.0 mg/g (dry weight) and 28.5 to 90.6 mg/g, respectively. Organic content (as indicated by loss on ignition or LOI) and iron(II) ranged from 3.1 to 27.0% and 26.5 to 64.9 mg/g, respectively. The dissolution dynamics of FIP extraction with a low solid/liquid ratio (1:25) indicated that a single application of 0.2% 2,2'-bipyridine extracted both iron(II) (Fe(II)) and phosphorus (as PO4(3-)) in sediments with different organic contents with low efficiency. The extraction efficiency of Fe(II) was improved by alteration of the solid/liquid ratio, but the effect was limited. However, addition of a 1:1000 solid/liquid ratio of 0.5 M potassium chloride to a 0.2% 2,2'-bipyridine solution significantly accelerated extraction of FIP with the release of Fe(II) and phosphorus toward equilibrium at approximately 150 hours. Further investigation demonstrated that 2,2'-bipyridine exhibited a higher selectivity in distinguishing FIP from phosphorus bound to ferric (Fe(III)) oxides or precipitated by calcium (Ca2+). Air-drying sediments significantly decreased the amount of extracted FIP, which indicates that fresh, wet sediment should be used in this type of FIP extraction. Based on experimental results using the proposed extraction protocol, (1) FIP in sediments of Fubao Bay had a predominant status in the lake sediment and accounted for 23.4 to 39.8% of total phosphorus, and (2) Fe(II)(FIP) released in the extraction is directly proportional to phosphorus(FIP) (Fe(II)(FIP) = 2.84 x P(FIP) + 0.0007; R2 = 0.97) with an average molar ratio of Fe(II)(FIP)/P(FIP) of 2.7. This study shows that FIP extraction with 2,2'-bipyridine is a robust method for releasing ferrous iron associated with phosphorus. Further, the high percentage of FIP in total phosphorus (40%) measured in the study site using this extraction method suggests that FIP might have been often underestimated in previous studies. PMID:23356019

Li, Qingman; Wang, Xingxiang; Bartlett, Rebecca; Pinay, Gilles; Kan, Dan; Zhang, Wen; Sun, Jingxian

2012-11-01

307

Reclamation of a bare industrial area contaminated by non-ferrous metals: In situ metal immobilization and revegetation  

Microsoft Academic Search

To reduce the environmental impact of a 135-ha bare industrial area with a highly phytotoxic soil contaminated by non-ferrous metals, a rehabilitation strategy was developed, aimed at the restoration of a vegetation cover. Two different techniques to overcome the high phytotoxicity of the soil were first evaluated on a laboratory scale: reduction of soil phytotoxicity by the addition of a

J. Vangronsveld; F. Van Assche; H. Clijsters

1995-01-01

308

INJECTION OF A FERROUS SULFATE/SODIUM DITHIONITE REDUCTANT FOR IN-SITU TREATMENT OF HEXAVALENT CHROMIUM  

EPA Science Inventory

An in situ pilot study was conducted to evaluate the performance of a ferrous iron-based reductant solution in treating hexavalent chromium within a saturated zone source area at a former industrial site in Charleston, South Carolina (USA). The hexavalent source area, consisting...

309

Arsenic Encapsulation Using Portland Cement With Ferrous Sulfate/Lime And Terra-BondTM Technologies - Microcharacterization And Leaching Studies  

EPA Science Inventory

This work reports the results of an investigation on the treatment and encapsulation of arsenic-containing materials by Portland cement with ferrous sulfate and lime (PFL) and Terra-BondTM, a commercially available patented technology. The arsenic materials treated we...

310

Selective dissolution of magnetic iron oxides in the acidammonium oxalate/ferrous iron extraction method--I. Synthetic samples  

E-print Network

a high magnetic signal com- pared to other magnetic iron oxides (for example, magnetite has a saturationSelective dissolution of magnetic iron oxides in the acid­ammonium oxalate/ferrous iron extraction. Synthetic samples containing a quartz matrix with 0.1 wt per cent of iron oxides were extracted with the AAO

Utrecht, Universiteit

311

Bioavailability and the mechanisms of intestinal absorption of iron from ferrous ascorbate and ferric polymaltose in experimental animals  

Microsoft Academic Search

The comparative bioavailability from matching quantities of iron in the form of ferrous ascorbate or ferric polymaltose was defined in rats. Studies were carried out in the intact animals under basal conditions and also when requirements for this metal were either increased or decreased by manipulating stores or erythropoietic activity. No significant difference was found in the total quantity of

G. Johnson; P. Jacobs

1990-01-01

312

Rehabilitation studies on an old non-ferrous waste dumping ground: effects of revegetation and metal immobilization by beringite  

Microsoft Academic Search

The possibility of restoring a vegetation on a bare, industrial dumping ground, strongly contaminated by several non-ferrous metals, was studied. The potential beneficial effect of this restoration on metal leaching was estimated. On a laboratory scale, the high phytotoxic potential of the dump's surface substratum could be reduced significantly by the addition of 5% beringite, a substance characterised by a

J. Vangronsveld; J. Sterckx; F. Van Assche; H. Clijsters

1995-01-01

313

Use of a Ferrous Sulfate - Sodium Dithionite Blend to Treat a Dissolved Phase Cr(VI) Plume  

EPA Science Inventory

A field study was conducted to evaluate the use of a combination of sodium dithionite and ferrous sulfate in creating an in situ redox zone for treatment of a dissolved phase Cr(VI) plume at a former industrial site. The reductant blend was injected into the path of a dissolved ...

314

IMPROVEMENT OF MAGNETICALLY SEPARATED FERROUS CONCENTRATE BY SHREDDING: A PERFORMANCE TEST. TEST NO. 4.07, RECOVERY 1, NEW ORLEANS  

EPA Science Inventory

This report describes a series of test runs in which ferrous product magnetically recovered from municipal waste was further shredded in a small (50 hp) hammermill to free attached or entrapped contaminant. A belt magnet was then used to separate metal from the liberated contamin...

315

Iron metabolism in aerobes: managing ferric iron hydrolysis and ferrous iron autoxidation  

PubMed Central

Aerobes and anaerobes alike express a plethora of essential iron enzymes; in the resting state, the iron atom(s) in these proteins are in the ferrous state. For aerobes, ferric iron is the predominant environmental valence form which, given ferric iron’s aqueous chemistry, occurs as ‘rust’, insoluble, bio-inert polymeric ferric oxide that results from the hydrolysis of [Fe(H2O)6]3+. Mobilizing this iron requires bio-ferrireduction which in turn requires managing the rapid autoxidation of the resulting FeII which occurs at pH > 6. This review examines the aqueous redox chemistry of iron and the mechanisms evolved in aerobes to suppress the ‘rusting out’ of FeIII and the ROS-generating autoxidation of FeII so as to make this metal ion available as the most ubiquitous prosthetic group in metallobiology. PMID:23264695

Kosman, Daniel J.

2012-01-01

316

Fast start-up of Anammox process with appropriate ferrous iron concentration.  

PubMed

In this study, three upflow column reactors were compared for anaerobic ammonium oxidation (Anammox) process start-up time with different ferrous iron concentration in feeding. Continuous experiments indicated that the start-up time of Anammox process could be shortened from 70 to 58d in R2 (0.06mM Fe(2+)) and 50d in R3 (0.09mM Fe(2+)). The Anammox activity appeared after 16days operation in R3. Quantitative PCR (q-PCR) analysis demonstrated a significant increase in quantity of Anammox bacteria in R3 compared with the other two reactors during entire operation. At the Fe(II) concentration of 0.09mM, the heme c levels inside Anammox cell and hydrazine dehydrogenase (HDH) activity increased dramatically, which could be the trigger of fast Anammox start-up. PMID:25164343

Bi, Zhen; Qiao, Sen; Zhou, Jiti; Tang, Xin; Zhang, Jie

2014-10-01

317

Inhibition of bacterial oxidation of ferrous iron by lead nitrate in sulfate-rich systems  

USGS Publications Warehouse

Inhibition of bacterial oxidation of ferrous iron (Fe(II)) by Pb(NO3)2 was investigated with a mixed culture of Acidithiobacillus ferrooxidans. The culture was incubated at 30 °C in ferrous-sulfate medium amended with 0–24.2 mM Pb(II) added as Pb(NO3)2. Anglesite (PbSO4) precipitated immediately upon Pb addition and was the only solid phase detected in the abiotic controls. Both anglesite and jarosite (KFe3(SO4)2(OH)6) were detected in inoculated cultures. Precipitation of anglesite maintained dissolved Pb concentrations at 16.9–17.6 ?M regardless of the concentrations of Pb(NO3)2 added. Fe(II) oxidation was suppressed by 24.2 mM Pb(NO3)2 addition even when anglesite was removed before inoculation. Experiments with 0–48 mM KNO3 demonstrated that bacterial Fe(II) oxidation decreased as nitrate concentration increased. Therefore, inhibition of Fe(II) oxidation at 24.2 mM Pb(NO3)2 addition resulted from nitrate toxicity instead of Pb addition. Geochemical modeling that considered the initial precipitation of anglesite to equilibrium followed by progressive oxidation of Fe(II) and the precipitation of jarosite and an amorphous iron hydroxide phase, without allowing plumbojarosite to precipitate were consistent with the experimental time-series data on Fe(II) oxidation under biotic conditions. Anglesite precipitation in mine tailings and other sulfate-rich systems maintains dissolved Pb concentrations below the toxicity threshold of A. ferrooxidans.

Wang, Hongmei; Gong, Linfeng; Cravotta, Charles A., III; Yang, Xiaofen; Tuovinen, Olli H.; Dong, Hailiang; Fu, Xiang

2013-01-01

318

Altered APP Carboxyl-Terminal Processing Under Ferrous Iron Treatment in PC12 Cells  

PubMed Central

Amyloid-? peptide (A?), generated by proteolytic cleavage of the amyloid precursor protein (APP), plays a pivotal role in the pathogenesis of Alzheimer's disease (AD). The key step in the generation of A? is cleavage of APP by beta-site APP-cleaving enzyme 1 (BACE1). Levels of BACE1 are increased in vulnerable regions of the AD brain, but the underlying mechanism is unknown. In the present study, we reported the effects of ferrous ions at subtoxic concentrations on the mRNA levels of BACE1 and a-disintegrin-and-metalloproteinase 10 (ADAM10) in PC12 cells and the cell responses to ferrous ions. The cell survival in PC12 cells significantly decreased with 0 to 0.3 mM FeCl2, with 0.6 mM FeCl2 treatment resulting in significant reductions by about 75%. 4,6-diamidino-2-phenylindole (DAPI) staining showed that the nuclei appeared fragmented in 0.2 and 0.3 mM FeCl2. APP-?-carboxyl terminal fragment (APP-?-CTF) associations with ADAM10 and APP-?-CTF with BACE1 were increased. Levels of ADAM10 and BACE1 mRNA increased in response to the concentrations of 0.25 mM, respectively. In addition, p-ERK and p-Bad (S112, S155) expressions were increased, suggesting that APP-CTF formation is related to ADAM10/BACE1 expression. Levels of Bcl-2 protein were increased, but significant changes were not observed in the expression of Bax. These data suggest that ion-induced enhanced expression of AMDA10/BACE1 could be one of the causes for APP-?/?-CTF activation. PMID:23776394

Kim, Chi Hyun

2013-01-01

319

Altered APP Carboxyl-Terminal Processing Under Ferrous Iron Treatment in PC12 Cells.  

PubMed

Amyloid-? peptide (A?), generated by proteolytic cleavage of the amyloid precursor protein (APP), plays a pivotal role in the pathogenesis of Alzheimer's disease (AD). The key step in the generation of A? is cleavage of APP by beta-site APP-cleaving enzyme 1 (BACE1). Levels of BACE1 are increased in vulnerable regions of the AD brain, but the underlying mechanism is unknown. In the present study, we reported the effects of ferrous ions at subtoxic concentrations on the mRNA levels of BACE1 and a-disintegrin-and-metalloproteinase 10 (ADAM10) in PC12 cells and the cell responses to ferrous ions. The cell survival in PC12 cells significantly decreased with 0 to 0.3 mM FeCl2, with 0.6 mM FeCl2 treatment resulting in significant reductions by about 75%. 4,6-diamidino-2-phenylindole (DAPI) staining showed that the nuclei appeared fragmented in 0.2 and 0.3 mM FeCl2. APP-?-carboxyl terminal fragment (APP-?-CTF) associations with ADAM10 and APP-?-CTF with BACE1 were increased. Levels of ADAM10 and BACE1 mRNA increased in response to the concentrations of 0.25 mM, respectively. In addition, p-ERK and p-Bad (S112, S155) expressions were increased, suggesting that APP-CTF formation is related to ADAM10/BACE1 expression. Levels of Bcl-2 protein were increased, but significant changes were not observed in the expression of Bax. These data suggest that ion-induced enhanced expression of AMDA10/BACE1 could be one of the causes for APP-?/?-CTF activation. PMID:23776394

Kim, Chi Hyun; Yoo, Yeong-Min

2013-06-01

320

Ferrous Sulfate Supplementation Causes Significant Gastrointestinal Side-Effects in Adults: A Systematic Review and Meta-Analysis  

PubMed Central

Background The tolerability of oral iron supplementation for the treatment of iron deficiency anemia is disputed. Objective Our aim was to quantify the odds of GI side-effects in adults related to current gold standard oral iron therapy, namely ferrous sulfate. Methods Systematic review and meta-analysis of randomized controlled trials (RCTs) evaluating GI side-effects that included ferrous sulfate and a comparator that was either placebo or intravenous (IV) iron. Random effects meta-analysis modelling was undertaken and study heterogeneity was summarised using I2 statistics. Results Forty three trials comprising 6831 adult participants were included. Twenty trials (n = 3168) had a placebo arm and twenty three trials (n = 3663) had an active comparator arm of IV iron. Ferrous sulfate supplementation significantly increased risk of GI side-effects versus placebo with an odds ratio (OR) of 2.32 [95% CI 1.74–3.08, p<0.0001, I2 = 53.6%] and versus IV iron with an OR of 3.05 [95% CI 2.07-4.48, p<0.0001, I2 = 41.6%]. Subgroup analysis in IBD patients showed a similar effect versus IV iron (OR = 3.14, 95% CI 1.34-7.36, p = 0.008, I2 = 0%). Likewise, subgroup analysis of pooled data from 7 RCTs in pregnant women (n = 1028) showed a statistically significant increased risk of GI side-effects for ferrous sulfate although there was marked heterogeneity in the data (OR = 3.33, 95% CI 1.19-9.28, p = 0.02, I2 = 66.1%). Meta-regression did not provide significant evidence of an association between the study OR and the iron dose. Conclusions Our meta-analysis confirms that ferrous sulfate is associated with a significant increase in gastrointestinal-specific side-effects but does not find a relationship with dose. PMID:25700159

Tolkien, Zoe; Stecher, Lynne; Mander, Adrian P.; Pereira, Dora I. A.; Powell, Jonathan J.

2015-01-01

321

THE THERMAL DECOMPOSITION OF THE 5,7-DIHALO-8QUINOLINOL RARE EARTH METAL CHELATES  

Microsoft Academic Search

S>The thermal decomposition of the 5,7-dichloro-, 5,7dibromo- and 5,7-; diiodo-8-quinolinol chelates of La, Ce, Pr, Nd, Sm, and Y was investigated on the ; thermobalance. The chelates decomposed in the temperature range from 65 to 125 ; deg C while the oxide levels were obtained from 395 to 805 deg C. Although the ; chelate thermal stability temperatures varied little

W Wendlandt

1957-01-01

322

Di-macrocyclic terephthalamide ligands as chelators for the PET radionuclide zirconium-89.  

PubMed

The development of bifunctional chelators (BFCs) which can stably chelate zirconium-89 ((89)Zr) while being conjugated to targeting molecules is an area of active research. Herein we report the first octadentate terephthalamide ligands, which are easily radiolabeled with (89)Zr and are highly stable in vitro. They represent a novel class of chelators, which are worthy of further development as BFCs for (89)Zr. PMID:25556851

Pandya, Darpan N; Pailloux, Sylvie; Tatum, David; Magda, Darren; Wadas, Thaddeus J

2015-02-11

323

Synthesis and antioxidant evaluation of some novel ortho-hydroxypyridine-4-one iron chelators  

PubMed Central

A series of ortho-hydroxypyridine-4-ones were prepared in high yields and evaluated for antioxidant and iron chelating activities. N1-H hydroxypyridinones Va, Vb, and Ve were the best radical scavengers in DPPH free radical scavenging assay. Compound Vb was proved to be the most potent compound in hydrogen peroxide scavenging assay. All of the synthesized compounds had very close chelating ability, compounds containing N1-CH3 hydroxypyridinone ring were stronger chelating agents. PMID:23181095

Mohammadpour, M.; Sadeghi, A.; Fassihi, A.; Saghaei, L.; Movahedian, A.; Rostami, M.

2012-01-01

324

Iron fortification technology development: new approaches.  

PubMed

The objective of our fortification technology development has been to deliver meaningful levels of bioavailable iron via commonly consumed foods and beverages without compromising taste, appearance, and stability. However, fortification of foods is accompanied with unsolved problems such as unacceptable taste, color, stability, and bioavailability. To solve these problems, we developed a fortification technology that prevents the iron-mediated undesirable taste and appearance of the final product while preserving stability and bioavailability. Iron was stabilized by applying principles of colloid chemistry (encapsulation), chelation, and electrochemical chemistry (redox modulation). Results from color and sensory evaluations showed that formulation of products using the new fortification technology known as "GrowthPlus" eliminated detrimental effects on taste, appearance, and product stability. Bioavailability evaluation using animal models and human subjects showed the GrowthPlus technology does not interfere with the bioavailability of iron from either ferrous bis-glycinate or ferrous fumarate. Multiple intervention trials showed that repeated consumption of the redox stabilized iron in the form of a powdered fruit beverage increased iron status indicators (hemoglobin and ferritin) and reduced iron deficiency anemia significantly in school children, adolescent girls, and pregnant women. PMID:16549477

Mehansho, Haile

2006-04-01

325

Mesoporous organosilica nanotubes containing a chelating ligand in their walls  

NASA Astrophysics Data System (ADS)

We report the synthesis of organosilica nanotubes containing 2,2'-bipyridine chelating ligands within their walls, employing a single-micelle-templating method. These nanotubes have an average pore diameter of 7.8 nm and lengths of several hundred nanometers. UV-vis absorption spectra and scanning transmission electron microscopy observations of immobilized nanotubes with an iridium complex on the bipyridine ligands showed that the 2,2'-bipyridine groups were homogeneously distributed in the benzene-silica walls. The iridium complex, thus, immobilized on the nanotubes exhibited efficient catalytic activity for water oxidation using Ce4+, due to the ready access of reactants to the active sites in the nanotubes.

Liu, Xiao; Goto, Yasutomo; Maegawa, Yoshifumi; Ohsuna, Tetsu; Inagaki, Shinji

2014-11-01

326

Ferrous Iron and Sulfur Oxidation and Ferric Iron Reduction Activities of Thiobacillus ferrooxidans Are Affected by Growth on Ferrous Iron, Sulfur, or a Sulfide Ore  

PubMed Central

Eight strains of Thiobacillus ferrooxidans (laboratory strains Tf-1 [= ATCC 13661] and Tf-2 [= ATCC 19859] and mine isolates SM-1, SM-2, SM-3, SM-4, SM-5, and SM-8) and three strains of Thiobacillus thiooxidans (laboratory strain Tt [= ATCC 8085] and mine isolates SM-6 and SM-7) were grown on ferrous iron (Fe2+), elemental sulfur (S0), or sulfide ore (Fe, Cu, and Zn). The cells were studied for their aerobic Fe2+ - and S0-oxidizing activities (O2 consumption) and anaerobic S0-oxidizing activity with ferric iron (Fe3+) (Fe2+ formation). Fe2+-grown T. ferrooxidans cells oxidized S0 aerobically at a rate of 2 to 4% of the Fe2+ oxidation rate. The rate of anaerobic S0 oxidation with Fe3+ was equal to the aerobic oxidation rate in SM-1, SM-3, SM-4, and SM-5, but was only one-half or less that in Tf-1, Tf-2, SM-2, and SM-8. Transition from growth on Fe2+ to that on S0 produced cells with relatively undiminished Fe2+ oxidation activities and increased S0 oxidation (both aerobic and anaerobic) activities in Tf-2, SM-4, and SM-5, whereas it produced cells with dramatically reduced Fe2+ oxidation and anaerobic S0 oxidation activities in Tf-1, SM-1, SM-2, SM-3, and SM-8. Growth on ore 1 of metal-leaching Fe2+-grown strains and on ore 2 of all Fe2+-grown strains resulted in very high yields of cells with high Fe2+ and S0 oxidation (both aerobic and anaerobic) activities with similar ratios of various activities. Sulfur-grown Tf-2, SM-1, SM-4, SM-6, SM-7, and SM-8 cultures leached metals from ore 3, and Tf-2 and SM-4 cells recovered showed activity ratios similar to those of other ore-grown cells. It is concluded that all the T. ferrooxidans strains studied have the ability to produce cells with Fe2+ and S0 oxidation and Fe3+ reduction activities, but their levels are influenced by growth substrates and strain differences. PMID:16348205

Suzuki, Isamu; Takeuchi, Travis L.; Yuthasastrakosol, Trin D.; Oh, Jae Key

1990-01-01

327

Branched polymeric media: boron-chelating resins from hyperbranched polyethylenimine.  

PubMed

Extraction of boron from aqueous solutions using selective resins is important in a variety of applications including desalination, ultrapure water production, and nuclear power generation. Today's commercial boron-selective resins are exclusively prepared by functionalization of styrene-divinylbenzene (STY-DVB) beads with N-methylglucamine to produce resins with boron-chelating groups. However, such boron-selective resins have a limited binding capacity with a maximum free base content of 0.7 eq/L, which corresponds to a sorption capacity of 1.16 ± 0.03 mMol/g in aqueous solutions with equilibrium boron concentration of ?70 mM. In this article, we describe the synthesis and characterization of a new resin that can selectively extract boron from aqueous solutions. We show that branched polyethylenimine (PEI) beads obtained from an inverse suspension process can be reacted with glucono-1,5-D-lactone to afford a resin consisting of spherical beads with high density of boron-chelating groups. This resin has a sorption capacity of 1.93 ± 0.04 mMol/g in aqueous solution with equilibrium boron concentration of ?70 mM, which is 66% percent larger than that of standard commercial STY-DVB resins. Our new boron-selective resin also shows excellent regeneration efficiency using a standard acid wash with a 1.0 M HCl solution followed by neutralization with a 0.1 M NaOH solution. PMID:22827255

Mishra, Himanshu; Yu, Changjun; Chen, Dennis P; Goddard, William A; Dalleska, Nathan F; Hoffmann, Michael R; Diallo, Mamadou S

2012-08-21

328

Protection from cold injury by deferoxamine, an iron chelator.  

PubMed

The presence of hydroxyl radical (OH) has been implicated in the pathogenesis of cold injury. Since iron is known to catalyze the OH formation responsible for cellular injury, this study was designed to examine whether an iron chelator such as deferoxamine can salvage a tissue from cold injury. Cold injury was induced in the hind limbs of rabbits. The experimental group received 0.6 mM of deferoxamine through the femoral vein prior to cooling of the limbs. Deferoxamine reduced the tissue injury, as evidenced by the decreased release of lactate dehydrogenase, a nonspecific marker for cellular injury. In addition, this drug inhibited OH formation and lipid peroxidation when examined by monitoring the formation of conjugated dienes and malonaldehyde, presumptive markers for lipid peroxidation. Rewarming of the cooled limbs was also associated with the loss of membrane phospholipids, with the corresponding accumulation of lysophosphoglycerides and free fatty acids, especially linoleic and arachidonic acids. Deferoxamine prevented the loss of phospholipids and inhibited the accumulation of amphipathic lipid products. These results indicates that deferoxamine salvaged the tissue from cold injury, possibly by preventing the formation of OH presumably by chelating iron, thus protecting the phospholipids from free radical attack. PMID:1325135

Maity, S; Lu, D; Russel, J C; Lyengar, J; Das, D K

1992-09-01

329

Immobilization of alcohol dehydrogenase onto metal-chelated cryogels.  

PubMed

In this presented work, poly(HEMA-GMA) cryogel was synthesized and used for the immobilization of alcohol dehydrogenase. For this, synthesized cryogels were functionalized with iminodiacetic acid and chelated with Zn(2+). This metal-chelated cryogels were used for the alcohol dehydrogenase immobilization and their kinetic parameters were compared with free enzyme. Optimum pH was found to be 7.0 for both immobilized and free enzyme preparations, while temperature optima for free and immobilized alcohol dehydrogenase was 25 °C. Kinetic constants such as Km, Vmax, and kcat for free and immobilized form of alcohol dehydrogenase were also investigated. kcat value of free enzyme was found to be 3743.9 min(-1), while kcat for immobilized enzyme was 3165.7 min(-1). Thermal stability of the free and immobilized alcohol dehydrogenase was studied and stability of the immobilized enzyme was found to be higher than free form. Also, operational stability and reusability profile of the immobilized alcohol dehydrogenase were investigated. Finally, storage stability of the free and immobilized alcohol dehydrogenase was studied, and at the end of the 60 days storage, it was demonstrated that, immobilized alcohol dehydrogenase was exhibited high stability than that of free enzyme. PMID:25715869

Uygun, Deniz Akta?; Akduman, Begüm; Uygun, Murat; Akgöl, Sinan; Denizli, Adil

2015-05-01

330

Chelating polymeric beads as potential therapeutics for Wilson's disease.  

PubMed

Wilson's disease is a genetic disorder caused by a malfunction of ATPase 7B that leads to high accumulation of copper in the organism and consequent toxic effects. We propose a gentle therapy to eliminate the excessive copper content with oral administration of insoluble non-resorbable polymer sorbents containing selective chelating groups for copper(II). Polymeric beads with the chelating agents triethylenetetramine, N,N-di(2-pyridylmethyl)amine, and 8-hydroxyquinoline (8HQB) were investigated. In a preliminary copper uptake experiment, we found that 8HQB significantly reduced copper uptake (using copper-64 as a radiotracer) after oral administration in Wistar rats. Furthermore, we measured organ radioactivity in rats to demonstrate that 8HQB radiolabelled with iodine-125 is not absorbed from the gastrointestinal tract after oral administration. Non-resorbability and the blockade of copper uptake were also confirmed with small animal imaging (PET/CT) in mice. In a long-term experiment with Wistar rats fed a diet containing the polymers, we have found that there were no signs of polymer toxicity and the addition of polymers to the diet led to a significant reduction in the copper contents in the kidneys, brains, and livers of the rats. We have shown that polymers containing specific ligands could potentially be novel therapeutics for Wilson's disease. PMID:24815561

Mattová, Jana; Pou?ková, Pavla; Ku?ka, Jan; Skodová, Michaela; Vetrík, Miroslav; St?pánek, Petr; Urbánek, Petr; Pet?ík, Miloš; Nový, Zbyn?k; Hrubý, Martin

2014-10-01

331

Iron chelation: a potential therapeutic strategy in oesophageal cancer  

PubMed Central

Raised intracellular iron has been identified as a potential aetiological factor in the development of several epithelial malignancies, including those of the gastrointestinal tract. The mechanism behind this increase is thought to include disorders of iron uptake and storage. Several iron chelators have been identified as potential anti-tumour agents, with much work undertaken to ascertain the exact mode of action. Despite this, there is little known about the role that these drugs play in the cellular iron metabolism of oesophageal cancer. Consequently, the present study looks to review the relationship of two clinically important iron-chelating agents, deferoxamine and deferasirox, on cellular iron uptake and storage in oesophageal squamous and adenocarcinoma. This provides important evidence for the debate about the role these agents have in the clinical management of such tumours. Linked Article This article is a commentary on Ford et al., pp. 1316–1328 of this issue. To view this paper visit http://dx.doi.org/10.1111/bph.12045 PMID:23278384

Keeler, BD; Brookes, MJ

2013-01-01

332

Synthesis and coordination properties of chelating dithiophenolate ligands.  

PubMed

Chelating 3,3'-R(1)-5,5'-R(2)-2,2'-dithiobiphenyl ligands (R(1) = R(2) = Cl, 4a; R(1) = R(2) = (t)Bu, 4b; R(1) = allyl, R(2) = H, 4c) and the 2,2'-methylenedibenzenethiol ligand (4d) were synthesized from the corresponding diols (1a-1d) via a three-step procedure involving a Miyazaki-Newman-Kwart rearrangement. Zinc complexes and a tin complex (for 4c) have been prepared to explore their coordination potential, and the substitution pattern, as well as the chelate ring size, is shown to severely effect their ligating properties. Four of the complexes have been characterized crystallographically in the solid state, and the nuclearity of the zinc complexes in solution has been studied by diffusion-ordered NMR spectroscopy. Depending on the ligand, zinc complexes [(4)Zn(4,4'-(t)Bu-bipyridine)](n) (5a-d) are monomeric (n = 1; 4b, 4c), monomeric in solution and dimeric in the solid state (n = 1, 2; 4a), or dimeric overall (n = 2; 4d). The tin complex (4c)SnPh(2) (6c) was additionally synthesized to prove the coordinating abilities of the allyl substituted ligand 4c. PMID:19035679

Ballmann, Joachim; Fuchs, Michael G G; Dechert, Sebastian; John, Michael; Meyer, Franc

2009-01-01

333

A microcapsule containing chelating resin selective for cadmium (II).  

PubMed

Ion exchange and solvent extraction technologies have been widely used for uptake and recovery of heavy metals from aqueous phases. However, different problems have been encountered on applying these techniques. Alternative to overcome these limitations is the microcapsulation of extractants within a functionalized polymeric shell. A chelating resin was prepared by treating Ceralite IR 400 with chromotropic acid and characterized by FTIR spectrum and sulphur analysis. Then, polystyrene microcapsules containing chelating resin were prepared by interfacial copolymerization of w/o/w emulsions. The adsorption of Zn(II), Cd(II), Ni(II), Co(II), Cu(II) and Pb(II) into microcapsule was studied by batch experiments. The effect of pH and counter ions on adsorption behavior has been investigated. Maximum uptake of Cd(II) into microcapsule was found in the presence of I ions and remained unchanged in the pH range 1-7 and the Cd(II) ions remained unaffected in the microcapsule even in 1 M HCl solution. The selectivity for Cd(II) was over four times greater than the other investigated metal ions. The breakthrough capacity for Cd(II) was 2.68 m mol/g microcapsule. The microcapsule packed mini-column has been applied for separation of Cd(II) from Zn(II), Pb(II), Cu(II), Ni(II) and Co(II). The microcapsule has also been tested for selective recovery of Cd(II) from river water. PMID:23505815

Gehlot, C L; Singh, Anuradha

2011-10-01

334

Predictors of DMSA chelatable lead, tibial lead, and blood lead in 802 Korean lead workers  

Microsoft Academic Search

OBJECTIVESTo examine the interrelations among chelatable lead (by dimercaptosuccinic acid, DMSA), tibial lead, and blood lead concentrations in 802 Korean workers with occupational exposure to lead and 135 employed controls with only environmental exposure to lead.METHODSThis was a cross sectional study wherein tibial lead, DMSA chelatable lead, and blood lead were measured. Linear regression was used to identify predictors of

A C Todd; B-K Lee; G-S Lee; K-D Ahn; E L Moshier; B S Schwartz

2001-01-01

335

Rapid anaerobic benzene oxidation with a variety of chelated Fe(III) forms  

Microsoft Academic Search

Techniques for stimulating aromatic hydrocarbon degradation in anaerobic portions of contaminated aquifers could be helpful in restoring polluted groundwater. Some studies have suggested that chelated Fe (III) might be an alternative electron acceptor that could be used instead of o2 for the bioremediation of aquifers contaminated with aromatic hydrocarbons. However, for this to be feasible an appropriate form of chelated

DEREK R. LOVLEY; JOAN C. WOODWARD; F. H. Chapelle

1996-01-01

336

Research paper Novel D-penicillamine carrying nanoparticles for metal chelation therapy  

E-print Network

Research paper Novel D-penicillamine carrying nanoparticles for metal chelation therapy protein precipitation. In the present studies, the Cu (I) chelator D-penicillamine was covalently with salts and serum. Release of D-penicillamine from the nanoparicles was achieved using reducing agents

Wisconsin at Madison, University of

337

21 CFR 176.150 - Chelating agents used in the manufacture of paper and paperboard.  

Code of Federal Regulations, 2011 CFR

...false Chelating agents used in the manufacture of paper and paperboard. 176.150...150 Chelating agents used in the manufacture of paper and paperboard. The substances...this section may be safely used in the manufacture of paper and paperboard, in...

2011-04-01

338

21 CFR 176.150 - Chelating agents used in the manufacture of paper and paperboard.  

Code of Federal Regulations, 2013 CFR

...false Chelating agents used in the manufacture of paper and paperboard. 176.150...150 Chelating agents used in the manufacture of paper and paperboard. The substances...this section may be safely used in the manufacture of paper and paperboard, in...

2013-04-01

339

21 CFR 176.150 - Chelating agents used in the manufacture of paper and paperboard.  

Code of Federal Regulations, 2012 CFR

...false Chelating agents used in the manufacture of paper and paperboard. 176.150...150 Chelating agents used in the manufacture of paper and paperboard. The substances...this section may be safely used in the manufacture of paper and paperboard, in...

2012-04-01

340

21 CFR 176.150 - Chelating agents used in the manufacture of paper and paperboard.  

Code of Federal Regulations, 2014 CFR

...false Chelating agents used in the manufacture of paper and paperboard. 176.150...150 Chelating agents used in the manufacture of paper and paperboard. The substances...this section may be safely used in the manufacture of paper and paperboard, in...

2014-04-01

341

Preparation and characterization of poly(amidoxime) chelating resin from polyacrylonitrile grafted sago starch  

Microsoft Academic Search

The preparation of a chelating ion-exchange resin containing amidoxime functional group was carried out by polyacrylonitrile (PAN) grafted sago starch. The PAN grafted copolymer was obtained by free-radical initiating process using ceric ammonium nitrate as an initiator. Conversion of nitrile groups of the grafted copolymer into the amidoxime was carried out by treatment with hydroxylamine under alkaline solution. The chelating

M. R. Lutfor; Sidik Silong; M. Z. Ab Rahman; Mansor Ahmad; Jelas Haron

2000-01-01

342

Studies on the oxygen toxicity after administration of chelate-forming agents in mice.  

PubMed

The influence of the chelating agents CaNa2-EDTA, penicillamine, dimercaprol, unithiol, dithiocarb, aurin tricarboxylic acid, salicylic acid, and acetylsalicylic acid on the toxicity of oxygen at elevated tension was studied in mice. With the possible exception of dimercaprol, no increase in toxic effects of oxygen was observed after administering these chelate-forming agents in the doses used. PMID:6406371

Renner, G; Kramer, H J

1983-03-01

343

Failure of Iron Chelators to Reduce Tumor Growth in Human Neuroblastoma Xenografts1  

Microsoft Academic Search

Neuroblastoma (NB) is a high risk tumor of childhood, and raised serum ferritin is an adverse prognostic factor. The hypothesis that iron chelation therapy impacts tumor status and patient prognosis through changes in iron metabolism has been systematically evaluated here in a xenograft model of human NB. One of two iron chelators was given in seven different regimens to nude

Ruth A. Selig; Cilinia Gramacho; Katy Sterling-Levis; Ian W. Fraser; Daya Naidoo

2002-01-01

344

Trypanosoma cruzi: Effect of benznidazole therapy combined with the iron chelator desferrioxamine in infected mice  

Microsoft Academic Search

Iron chelators have been employed in various studies aimed at evaluating the relationship between the iron status of the host and the development of infection. In the present study, the effects of benznidazole (BZ) therapy in combination with the iron chelator desferrioxamine (DFO) on the development of infection in mice inoculated with Trypanosoma cruzi Y strain have been investigated. Infected

Amanda Fortes Francisco; Paula Melo de Abreu Vieira; Jerusa Marilda Arantes; Maria Lúcia Pedrosa; Helen Rodrigues Martins; Maisa Silva; Vanja Maria Veloso; Marta de Lana; Maria Terezinha Bahia; Washington Luiz Tafuri; Cláudia Martins Carneiro

2008-01-01

345

Deferoxamine augments growth and pathogenicity of Rhizopus, while hydroxypyridinone chelators have no effect  

Microsoft Academic Search

Deferoxamine augments growth and pathogenicity of Rhizopus, while hydroxypyridinone chelators have no effect. Deferoxamine (DFO), when used in dialysis patients, is a well recognized risk factor for the development of mucormycosis caused by Rhizopus. This study compares, both in vivo and in vitro, the effects produced on Rhizopus by DFO and by two chelators of the hydroxypyridinone class, L1 and

Johan R Boelaert; Jan Van Cutsem; Marielle de Locht; Yves-Jacques Schneider; Robert R Crichton

1994-01-01

346

Diversity of Ferrous Iron-Oxidizing, Nitrate-Reducing Bacteria and their Involvement in Oxygen-Independent Iron Cycling  

Microsoft Academic Search

In previous studies, three different strains (BrG1, BrG2, and BrG3) of ferrous iron-oxidizing, nitrate-reducing bacteria were obtained from freshwater sediments. All three strains were facultative anaerobes and utilized a variety of organic substrates and molecular hydrogen with nitrate as electron acceptor. In this study, analyses of 16S rDNA sequences showed that strain BrG1 was affiliated with the genus Acidovorax, strain

Kristina L. Straub; Wilhelm A. Schönhuber; Berit E. E. Buchholz-Cleven; Bernhard Schink

2004-01-01

347

Kinetics absorption characteristics of ferrous glycinate in SD rats and its impact on the relevant transport protein.  

PubMed

Ferrous glycinate (Fe-Gly) maintains high bioavailability in animals, but its exact absorption mechanism is still unknown. Here, we studied on the absorption kinetics of ferrous glycinate and its impact on the relevant transport protein in Sprague-Dawley (SD) rats. A total of 72 SD rats (male, BW 100?±?6.25 g) were randomly allotted to three treatments. These treatments were perfused with 1 mL of normal saline, ferrous sulfate (FeSO4), and ferrous glycinate (71.35 mg/L as iron) separately. Four rats were selected from each treatment for collection of blood from the tails at certain times (15, 30, 45, 60, 75, 90, 120, 240, and 360 min) after gavage. Moreover, other six rats selected from each treatment were slaughtered for sampling after gavage at 2, 4, and 6 h to evaluate the expression of intestinal transport protein. Pharmacokinetic parameters of iron were determined by one-compartmental analysis. Compared with FeSO4, the peak plasma concentration of iron (C max) is higher in the rats given gavage with Fe-Gly (P?

Zhuo, Zhao; Fang, Shenglin; Yue, Min; Zhang, Yiwei; Feng, Jie

2014-05-01

348

Effects of Ferrous Chloride and Iron-Dextran on Lipid Peroxidation In Vivo in Vitamin E and Selenium Adequate and Deficient Rats1  

Microsoft Academic Search

The effects of intraperitoneally injected ferrous chloride and iron-dextran on lipid peroxidation in vivo were assessed. Peroxidation was esti mated by measuring ethane, a volatile autoxidation product of omega-3-un- saturated fatty acids. Rats supplemented with 0.1 ppm dietary selenium and rats supplemented with 0.1 ppm selenium and 200 IU vitamin E\\/kg diet were injected with ferrous chloride at 30 mg

JOHN J. DOUGHERTY; WILLIAM A. CROFT; WILLIAM G. HOEKSTRA

349

Brazilian Thalassemia Association protocol for iron chelation therapy in patients under regular transfusion  

PubMed Central

In the absence of an iron chelating agent, patients with beta-thalassemia on regular transfusions present complications of transfusion-related iron overload. Without iron chelation therapy, heart disease is the major cause of death; however, hepatic and endocrine complications also occur. Currently there are three iron chelating agents available for continuous use in patients with thalassemia on regular transfusions (desferrioxamine, deferiprone, and deferasirox) providing good results in reducing cardiac, hepatic and endocrine toxicity. These practice guidelines, prepared by the Scientific Committee of Associação Brasileira de Thalassemia (ABRASTA), presents a review of the literature regarding iron overload assessment (by imaging and laboratory exams) and the role of T2* magnetic resonance imaging (MRI) to control iron overload and iron chelation therapy, with evidence-based recommendations for each clinical situation. Based on this review, the authors propose an iron chelation protocol for patients with thalassemia under regular transfusions. PMID:24478610

Veríssimo, Monica Pinheiro de Almeida; Loggetto, Sandra Regina; Fabron Junior, Antonio; Baldanzi, Giorgio Roberto; Hamerschlak, Nelson; Fernandes, Juliano Lara; Araujo, Aderson da Silva; Lobo, Clarisse Lopes de Castro; Fertrin, Kleber Yotsumoto; Berdoukas, Vasilios Antonios; Galanello, Renzo

2013-01-01

350

Competitive coordination between lead and oligoelements with respect to some therapeutic heavy-metal chelators  

NASA Astrophysics Data System (ADS)

The competitive complexation of Ca2+, Fe2+, Cu2+, Zn2+, and Pb2+ toward ethylene diamine tetraacetate (EDTA), dimercaprol and D-penicillamine, three liganding agents commonly used in chelation therapy against heavy metal, especially lead, poisonings is examined by means of B3LYP calculations, natural population analyses, and the topological analysis of the electron localization function. It is shown that Pb2+ can displace any of Ca2+, Fe2+, Cu2+, or Zn2+ chelated by any of dimercaprol or D-penicillamine, but can only displace Ca2+ if EDTA is concerned. The first two chelators thus appear as better entities than EDTA to be used in chelation therapy, where in vivo selective complexation is essential. Moreover, the comparison of the bonding characteristics of Pb2+ with those of the other cations allows deriving three features to be taken into account in designing new chelators expecting to have an increased selectivity toward this cation.

Gourlaouen, C.; Parisel, O.

351

Method for separating metal chelates from other materials based on solubilities in supercritical fluids  

DOEpatents

A method for separating a desired metal or metalloi from impurities using a supercritical extraction process based on solubility differences between the components, as well as the ability to vary the solvent power of the supercritical fluid, is described. The use of adduct-forming agents, such as phosphorous-containing ligands, to separate metal or metalloid chelates in such processes is further disclosed. In preferred embodiments, the extraction solvent is supercritical carbon dioxide and the chelating agent is selected from the group consisting of .beta.-diketones; phosphine oxides, such as trialkylphosphine oxides, triarylphosphine oxides and alkylarylphosphine oxides; phosphinic acids; carboxylic acids; phosphates, such as trialkylphosphates, triarylphosphates and alkylarylphosphates; crown ethers; dithiocarbamates; phosphine sulfides; phosphorothioic acids; thiophosphinic acids; halogenated analogs of these chelating agents; and mixtures of these chelating agents. In especially preferred embodiments, at least one of the chelating agents is fluorinated.

Wai, Chien M. (Moscow, ID); Smart, Neil G. (Workington, GB); Phelps, Cindy (Moscow, ID)

2001-01-01

352

Combined chelation of lead (II) by deferasirox and deferiprone in rats as biological model.  

PubMed

In order to investigate the capability of two chelators deferasirox (DFX or ICL670) and deferiprone (L1) in removing lead from the body, the present research was performed. Two does levels of 40 and 80 mg/kg body weight of lead (II) chloride was given to rats as biological model for 45 days. After 45 days, some toxicity symptoms were observed in rats such as loss of hair and weight, appearance of red dots around eyes, weakness and irritability. After lead application, chelation therapy with DFX and L1 as mono and combined (DFX, L1 and DFX + L1) was done for 10 days. After chelation therapy, lead level in different tissues reduced. The combined chelation therapy results showed that these chelators are able to remove lead from the body and toxicity symptoms decreased. The combined therapy results (DFX + L1) show higher efficacy and lower toxicity compared to single therapies. PMID:24309925

Balooch, F Dahooee; Fatemi, S J; Iranmanesh, M

2014-02-01

353

Removal of cadmium by combining deferasirox and desferrioxamine chelators in rats.  

PubMed

An investigation was conducted to evaluate the ability of two chelators, deferasirox and desferrioxamine (DFO), in removing cadmium from biological system. The potential efficiency of those chelators were investigated after cadmium administration for 60 days following two dose levels of 20 and 40 mg/kg body weight daily to male rats. However, abnormalities were observed in clinical signs after cadmium administration, such as yellowish discoloration of hair, flaccid and hypotonic muscles, irritability, weakness and loss of weight. The hypothesis that the two chelators might be more efficient as combined therapy than single therapy in removing metal ions from the body was considered. In this way, two known chelators, deferasirox and DFO were chosen and tested in the acute rat model. The chelation therapy results show that deferasirox and DFO are able (?)to remove cadmium ions from the body, while iron concentration returned to the normal level and symptoms are decreased. PMID:22134990

Fatemi, S Jamilaldine; Saljooghi, Amir Shokooh; Balooch, Faezeh Dahooee; Iranmanesh, Marzieh; Golbafan, Mohammad Reza

2012-02-01

354

Advances in transient (pulsed) eddy current for inspection of multi-layer aluminum structures in the presence of ferrous fasteners  

NASA Astrophysics Data System (ADS)

An experimental investigation of the electromagnetic processes underlying transient (pulsed) eddy current inspection of aircraft wing structures in the vicinity of ferrous fasteners is performed. The separate effects of transient excitation of ferrous fastener and eddy currents induced in the surrounding aluminum structure are explored using a transmit-receive configuration with transient excitation of a steel rod, an aluminum plate with a bore hole and a steel rod through the bore hole. Observations are used to interpret results from a coupled driving and differential coil sensing unit applied to detect fatigue cracks emanating from bolt holes in aluminum structures with ferrous fasteners present. In particular, it is noted that abrupt magnetization of the fastener, by the probe's central driving unit, can transfer flux and consequently, induce strong eddy current responses deep within the aluminum structure in the vicinity of the bore hole. Rotation of the probe, centered over the fastener, permits detection of subsurface discontinuities, such as cracks, by the pair of differentially connected pickup coils.

Desjardins, D. R.; Vallières, G.; Whalen, P. P.; Krause, T. W.

2012-05-01

355

Were mercury emission factors for Chinese non-ferrous metal smelters overestimated? Evidence from onsite measurements in six smelters.  

PubMed

Non-ferrous metal smelting takes up a large proportion of the anthropogenic mercury emission inventory in China. Zinc, lead and copper smelting are three leading sources. Onsite measurements of mercury emissions were conducted for six smelters. The mercury emission factors were 0.09-2.98 g Hg/t metal produced. Acid plants with the double-conversion double-absorption process had mercury removal efficiency of over 99%. In the flue gas after acid plants, 45-88% was oxidized mercury which can be easily scavenged in the flue gas scrubber. 70-97% of the mercury was removed from the flue gas to the waste water and 1-17% to the sulfuric acid product. Totally 0.3-13.5% of the mercury in the metal concentrate was emitted to the atmosphere. Therefore, acid plants in non-ferrous metal smelters have significant co-benefit on mercury removal, and the mercury emission factors from Chinese non-ferrous metal smelters were probably overestimated in previous studies. PMID:22892573

Zhang, Lei; Wang, Shuxiao; Wu, Qingru; Meng, Yang; Yang, Hai; Wang, Fengyang; Hao, Jiming

2012-12-01

356

First-principles study of intermediate-spin ferrous iron in the Earth's lower mantle  

E-print Network

Spin crossover of iron is of central importance in solid Earth geophysics. It impacts all physical properties of minerals that altogether constitute $\\sim 95$ vol\\% of the Earth's lower mantle: ferropericlase [(Mg,Fe)O] and Fe-bearing magnesium silicate (MgSiO$_3$) perovskite. Despite great strides made in the past decade, the existence of intermediate-spin (IS) state in ferrous iron (Fe$^{2+}$) (with total electron spin $S=1$) and its possible role in the pressure-induced spin crossover in these lower-mantle minerals still remain controversial. Using density functional theory $+$ self-consistent Hubbard $U$ (DFT$+U_{sc}$) calculations, we investigate all possible types of IS states of Fe$^{2+}$ in (Mg,Fe)O and (Mg,Fe)SiO$_3$ perovskite. Among the possible IS states in these minerals, the most probable IS state has an electronic configuration that significantly reduces the electron overlap and the iron nuclear quadrupole splitting (QS). These most probable IS states, however, are still energetically disfavore...

Hsu, Han

2014-01-01

357

INTERPRETATION OF AT-LINE SPECTRA FROM AFS-2 BATCH #3 FERROUS SULFAMATE TREATMENT  

SciTech Connect

Spectra from the “at-line” spectrometer were obtained during the ferrous sulfamate (FS) valence adjustment step of AFS-2 Batch #3 on 9/18/2013. These spectra were analyzed by mathematical principal component regression (PCR) techniques to evaluate the effectiveness of this treatment. Despite the complications from Pu(IV), we conclude that all Pu(VI) was consumed during the FS treatment, and that by the end of the treatment, about 85% was as Pu(IV) and about 15% was as Pu(III). Due to the concerns about the “odd” shape of the Pu(IV) peak and the possibility of this behavior being observed in the future, a follow-up sample was sent to SRNL to investigate this further. Analysis of this sample confirmed the previous results and concluded that it “odd” shape was due to an intermediate acid concentration. Since the spectral evidence shows complete reduction of Pu(VI) we conclude that it is appropriate to proceed with processing of this the batch of feed solution for HB-Line including the complexation of the fluoride with aluminum nitrate.

Kyser, E.; O'Rourke, P.

2013-12-10

358

First-principles study of intermediate-spin ferrous iron in the Earth's lower mantle  

NASA Astrophysics Data System (ADS)

Spin crossover of iron is of central importance in solid Earth geophysics. It impacts all physical properties of minerals that altogether constitute ˜95 vol% of the Earth's lower mantle: ferropericlase [(Mg,Fe)O] and Fe-bearing magnesium silicate (MgSiO3) perovskite. Despite great strides made in the past decade, the existence of an intermediate-spin (IS) state in ferrous iron (Fe2 +) (with total electron spin S =1 ) and its possible role in the pressure-induced spin crossover in these lower-mantle minerals still remain controversial. Using density functional theory + self-consistent Hubbard U (DFT+Usc ) calculations, we investigate all possible types of IS states of Fe2 + in (Mg,Fe)O and (Mg,Fe)SiO3 perovskite. Among the possible IS states in these minerals, the most probable IS state has an electronic configuration that significantly reduces the electron overlap and the iron nuclear quadrupole splitting (QS). These most probable IS states, however, are still energetically disfavored, and their QSs are inconsistent with Mössbauer spectra. We therefore conclude that IS Fe2 + is highly unlikely in the Earth's lower mantle.

Hsu, Han; Wentzcovitch, Renata M.

2014-11-01

359

The effects of varying substrate angle on feature quality in femtosecond laser ablation of ferrous alloys  

NASA Astrophysics Data System (ADS)

This paper presents the results of an experimental study to establish process parameters for repeatable, high quality ablated features in ferrous substrates using a Ti:sapphire femtosecond laser system. Initial trials with stainless steel substrates were conducted in ambient atmospheric conditions. Laser power and exposure parameters were varied, in addition to the angle of the substrate relative to the beam. Ablated holes were sectioned, and examined. Data was reduced according to the Taguchi/ANOVA method. The optimal process parameter set minimized the figures of merit for quality or accuracy of the ablated hole. In trials using pulsed ablations, high accuracy holes were associated with laser power greater than 600 mW, substrate angles of 30-45 degrees, and 1000 pulses. In the dwell experiments, high accuracy holes were achieved with a similar power level, and a 1-second dwell time. In contrast to the pulse results, a shallow substrate angle (30 degrees or less) yielded favorable results. In subsequent trials, kovar substrates were processed in a vacuum at constant fluence with a 1-second dwell time. A localized flow of nitrogen removed ablation products. Results were compared to those of the initial trial, leading to significant observations regarding the use of vacuum and secondary process gas.

Palmer, Jeremy A.; McDaniel, Karen L.; Harris, Marc F.; Lumia, Ronald; Griffith, Michelle L.

2004-09-01

360

The chemistry of the thermal decomposition of pseudobrookite ferrous titanium oxides  

SciTech Connect

The thermal decomposition of two metastable ferrous titanium oxide compounds of commercial interest have been studied by in situ x-ray and neutron diffraction at elevated temperatures as well as by {sup 57}Fe Mossbauer effect spectroscopy. Thermal decomposition was monitored by collecting neutron diffraction data (taken at the Argonne National Laboratory Intense Pulsed Neutron Source (IPNS) powder diffractometers) at 30-min intervals at 900 and 1,000{degree}C. Previous work has shown that each of these materials (pseudobrookite structure, AB{sub 2}O{sub 5}), (Mn{sub 0.05}Fe{sub 0.33}Ti{sub 0.52})(Ti{sub 2.0})O{sub 5} and (Mg{sub 0.21}Fe{sub 0.33}Ti{sub 0.46})(Ti{sub 1.9}Mg{sub 0.1})O{sub 5}, has a significant amount of Ti in the +3 oxidation state and is completely ordered (no Fe located in the B site). The results of these in situ diffraction studies show that, prior to the thermal decomposition of the slags, there is a redistribution of cations within the pseudobrookite structure.

Teller, R.G.; Antonio, M.R. (BP Research, Cleveland, OH (USA)); Grau, A.E.; Gueguin, M. (QIT-Fer et Titane Inc., Sorel, Quebec (Canada)); Kostiner, E. (Univ. of Connecticut, Storrs (USA))

1990-10-01

361

Role of Ferrous Ions in Synthetic Cobaltous Sulfide Leaching of Thiobacillus ferrooxidans  

PubMed Central

Microbiological leaching of synthetic cobaltous sulfide (CoS) was investigated with a pure strain of Thiobacillus ferroxidans. The strain could not grow on CoS-salts medium in the absence of ferrous ions (Fe2+). However, in CoS-salts medium supplemented with 18 mM Fe2+, the strain utilized both Fe2+ and the sulfur moiety in CoS for growth, resulting in an enhanced solubilization of Co2+. Cell growth on sulfur-salts medium was strongly inhibited by Co2+, and this inhibition was completely protected by Fe2+. Cobalt-resistant cells, obtained by subculturing the strain in medium supplemented with both Fe2+ and Co2+, brought a marked decrease in the amount of Fe2+ absolutely required for cell growth on CoS-salts medium. As one mechanism of protection by Fe2+, it is proposed that the strain utilizes one part of Fe2+ externally added to CoS-salts medium to synthesize the cobalt-resistant system. Since a similar protective effect by Fe2+ was also observed for cell inhibition by stannous, nickel, zinc, silver, and mercuric ions, a new role of Fe2+ in bacterial leaching in T. ferrooxidans is proposed. PMID:16346615

Sugio, Tsuyoshi; Domatsu, Chitoshi; Tano, Tatsuo; Imai, Kazutami

1984-01-01

362

Fluoride ion recognition by chelating and cationic boranes.  

PubMed

Because of the ubiquity of fluoride ions and their potential toxicity at high doses, researchers would like to design receptors that selectively detect this anion. Fluoride is found in drinking water, toothpaste, and osteoporosis drugs. In addition, fluoride ions also can be detected as an indicator of uranium enrichment (via hydrolysis of UF(6)) or of the chemical warfare agent sarin, which releases the ion upon hydrolysis. However, because of its high hydration enthalpy, the fluoride anion is one of the most challenging targets for anion recognition. Among the various recognition strategies that are available, researchers have focused a great deal of attention on Lewis acidic boron compounds. These molecules typically interact with fluoride anions to form the corresponding fluoroborate species. In the case of simple triarylboranes, the fluoroborates are formed in organic solvents but not in water. To overcome this limitation, this Account examines various methods we have pursued to increase the fluoride-binding properties of boron-based receptors. We first considered the use of bifunctional boranes, which chelate the fluoride anion, such as 1,8-diborylnaphthalenes or heteronuclear 1-boryl-8-mercurio-naphthalenes. In these molecules, the neighboring Lewis acidic atoms can cooperatively interact with the anionic guest. Although the fluoride binding constants of the bifunctional compounds exceed those of neutral monofunctional boranes by several orders of magnitude, the incompatibility of these systems with aqueous media limits their utility. More recently, we have examined simple triarylboranes whose ligands are decorated by cationic ammonium or phosphonium groups. These cationic groups increase the electrophilic character of these boranes, and unlike their neutral analogs, they are able to complex fluoride in aqueous media. We have also considered cationic boranes, which form chelate complexes with fluoride anions. Our work demonstrates that Coulombic and chelate effects are additive and can be combined to boost the anion affinity of Lewis acidic hosts. The boron compounds that we have investigated present a set of photophysical and electrochemical properties that can serve to signal the fluoride-binding event. We can also apply this approach to cyanide complexation and are continuing our investigations in that area. PMID:19140747

Hudnall, Todd W; Chiu, Ching-Wen; Gabbaï, François P

2009-02-17

363

Efficacy, Tolerability, and Acceptability of Iron Hydroxide Polymaltose Complex versus Ferrous Sulfate: A Randomized Trial in Pediatric Patients with Iron Deficiency Anemia.  

PubMed

Iron polymaltose complex (IPC) offers similar efficacy with superior tolerability to ferrous sulfate in adults, but randomized trials in children are rare. In a prospective, open-label, 4-month study, 103 children aged >6 months with iron deficiency anemia (IDA) were randomized to IPC once daily or ferrous sulfate twice daily, (both 5?mg iron/kg/day). Mean increases in Hb to months 1 and 4 with IPC were 1.2 ± 0.9?g/dL and 2.3 ± 1.3?g/dL, respectively, (both P = 0.001 versus baseline) and 1.8 ± 1.7?g/dL and 3.0 ± 2.3?g/dL with ferrous sulfate (both P = 0.001 versus baseline) (n.s. between groups). Gastrointestinal adverse events occurred in 26.9% and 50.9% of IPC and ferrous sulfate patients, respectively (P = 0.012). Mean acceptability score at month 4 was superior with IPC versus ferrous sulfate (1.63 ± 0.56 versus 2.14 ± 0.75, P = 0.001). Efficacy was comparable with IPC and ferrous sulfate over a four-month period in children with IDA, but IPC was associated with fewer gastrointestinal adverse events and better treatment acceptability. PMID:22121379

Yasa, Beril; Agaoglu, Leyla; Unuvar, Emin

2011-01-01

364

Efficacy, Tolerability, and Acceptability of Iron Hydroxide Polymaltose Complex versus Ferrous Sulfate: A Randomized Trial in Pediatric Patients with Iron Deficiency Anemia  

PubMed Central

Iron polymaltose complex (IPC) offers similar efficacy with superior tolerability to ferrous sulfate in adults, but randomized trials in children are rare. In a prospective, open-label, 4-month study, 103 children aged >6 months with iron deficiency anemia (IDA) were randomized to IPC once daily or ferrous sulfate twice daily, (both 5?mg iron/kg/day). Mean increases in Hb to months 1 and 4 with IPC were 1.2 ± 0.9?g/dL and 2.3 ± 1.3?g/dL, respectively, (both P = 0.001 versus baseline) and 1.8 ± 1.7?g/dL and 3.0 ± 2.3?g/dL with ferrous sulfate (both P = 0.001 versus baseline) (n.s. between groups). Gastrointestinal adverse events occurred in 26.9% and 50.9% of IPC and ferrous sulfate patients, respectively (P = 0.012). Mean acceptability score at month 4 was superior with IPC versus ferrous sulfate (1.63 ± 0.56 versus 2.14 ± 0.75, P = 0.001). Efficacy was comparable with IPC and ferrous sulfate over a four-month period in children with IDA, but IPC was associated with fewer gastrointestinal adverse events and better treatment acceptability. PMID:22121379

Yasa, Beril; Agaoglu, Leyla; Unuvar, Emin

2011-01-01

365

Clinically Approved Iron Chelators Influence Zebrafish Mortality, Hatching Morphology and Cardiac Function  

PubMed Central

Iron chelation therapy using iron (III) specific chelators such as desferrioxamine (DFO, Desferal), deferasirox (Exjade or ICL-670), and deferiprone (Ferriprox or L1) are the current standard of care for the treatment of iron overload. Although each chelator is capable of promoting some degree of iron excretion, these chelators are also associated with a wide range of well documented toxicities. However, there is currently very limited data available on their effects in developing embryos. In this study, we took advantage of the rapid development and transparency of the zebrafish embryo, Danio rerio to assess and compare the toxicity of iron chelators. All three iron chelators described above were delivered to zebrafish embryos by direct soaking and their effects on mortality, hatching and developmental morphology were monitored for 96 hpf. To determine whether toxicity was specific to embryos, we examined the effects of chelator exposure via intra peritoneal injection on the cardiac function and gene expression in adult zebrafish. Chelators varied significantly in their effects on embryo mortality, hatching and morphology. While none of the embryos or adults exposed to DFO were negatively affected, ICL -treated embryos and adults differed significantly from controls, and L1 exerted toxic effects in embryos alone. ICL-670 significantly increased the mortality of embryos treated with doses of 0.25 mM or higher and also affected embryo morphology, causing curvature of larvae treated with concentrations above 0.5 mM. ICL-670 exposure (10 µL of 0.1 mM injection) also significantly increased the heart rate and cardiac output of adult zebrafish. While L1 exposure did not cause toxicity in adults, it did cause morphological defects in embryos at 0.5 mM. This study provides first evidence on iron chelator toxicity in early development and will help to guide our approach on better understanding the mechanism of iron chelator toxicity. PMID:25329065

Hamilton, Jasmine L.; Hatef, Azadeh; Imran ul-haq, Muhammad; Nair, Neelima; Unniappan, Suraj; Kizhakkedathu, Jayachandran N.

2014-01-01

366

Next generation barrier CMP slurry with novel weakly alkaline chelating agent  

NASA Astrophysics Data System (ADS)

To strengthen the device performance with the pattern wafer by enhancing the Cu polishing rate and improve the surface roughness with the Cu lines, a new weakly alkaline chelating agent with a barrier slurry is developed to meet the process demand of the advanced barrier chemical mechanical planarization (CMP). This new chelating agent has a stronger chelating ability and a lower pH value than the previous generation-FA/O I chelating agent researched before. Without an unstable oxidant agent added in the polishing slurry, it is difficult to enhance the copper polishing rate during the barrier CMP. The stronger chelating ability of the new chelating agent could increase the copper polishing rate along with controlling the Cu/Ta/TEOS removal rate selectivity to meet the requirements of the IC fabrication process. Thus it has solved the problem of excessive roughness due to the lower polishing rate, avoiding reducing the device performance with the pattern wafer. The new chelating agent with its lower pH value could make it possible to protect the low-k dielectric under the barrier layer from structurally breaking. The CMP experiment was performed on the 12 inch MIT 854 pattern wafers with the barrier slurry containing the new weakly alkaline chelating agent. By the DOE optimization, the results indicate that as the new chelating agent concentration in the slurry was up to 2.5 mL/L, the copper polishing rate is about 31.082 nm/min. Meanwhile, the wafer surface has a rather low roughness value of 0.693 nm (10 × 10 ?m), the correction ability with the above slurry is adapted to the next generation barrier CMP and the k value of the low-k dielectric seems to have no k-shift. All the results presented show that the new weakly alkaline chelating agent with its superior performance can be used for the advanced barrier CMP.

Shiyan, Fan; Yuling, Liu; Ming, Sun; Jiying, Tang; Chenqi, Yan; Hailong, Li; Shengli, Wang

2015-01-01

367

Mesoporous organosilica nanotubes containing a chelating ligand in their walls  

SciTech Connect

We report the synthesis of organosilica nanotubes containing 2,2?-bipyridine chelating ligands within their walls, employing a single-micelle-templating method. These nanotubes have an average pore diameter of 7.8 nm and lengths of several hundred nanometers. UV-vis absorption spectra and scanning transmission electron microscopy observations of immobilized nanotubes with an iridium complex on the bipyridine ligands showed that the 2,2?-bipyridine groups were homogeneously distributed in the benzene-silica walls. The iridium complex, thus, immobilized on the nanotubes exhibited efficient catalytic activity for water oxidation using Ce{sup 4+}, due to the ready access of reactants to the active sites in the nanotubes.

Liu, Xiao; Goto, Yasutomo; Maegawa, Yoshifumi; Inagaki, Shinji, E-mail: inagaki@mosk.tytlabs.co.jp [Toyota Central R and D Laboratories, Inc., Nagakute, Aichi 480-1192 (Japan); Japan Science and Technology Agency (JST)/ACT-C, Nagakute, Aichi, 480-1192 (Japan); Ohsuna, Tetsu [Toyota Central R and D Laboratories, Inc., Nagakute, Aichi 480-1192 (Japan)

2014-11-01

368

Iron chelation therapy in myelodysplastic syndromes: where do we stand?  

PubMed Central

Anemia leading to transfusion dependency (TD) and iron overload (IO) is commonly observed in patients with myelodysplastic syndromes (MDS). In MDS, TD and IO have been retrospectively associated with inferior survival and worse clinical outcomes, including cardiac, hepatic and endocrine dysfunction, and, in some analyses, with leukemic progression and infectious complications. Although suggested by retrospective analyses, clear prospective documentation of the beneficial effects of iron chelation therapy (ICT) on organ function and survival in MDS patients with TD and IO is currently lacking. Consequently, the role of ICT in MDS patients with TD and IO remains a very controversial aspect in the management of MDS. In this review, the authors summarize the current knowledge regarding IO in MDS and the role of ICT. PMID:23991926

Mitchell, Mhairi; Gore, Steven D; Zeidan, Amer M

2014-01-01

369

Aggregation in Amphiphilic Macrocycle-Substituted Gd(3+) DOTA-Type Chelates Is Affected by the Regiochemistry of Substitution.  

PubMed

Gd(3+) chelates of macrocyclic bifunctional chelators (BFCs) can differentiate into two regioisomers: corner and side. These isomers afford different orientations of chelate relative to conjugate. These differences alter the self-assembly, tumbling, and effectiveness as magnetic resonance imaging contrast agents of the two biphenyl conjugate isomers. PMID:25692481

Webber, Benjamin C; Cassino, Claudio; Botta, Mauro; Woods, Mark

2015-03-01

370

Long-term Chelation Therapy in Thalassaemia Major: Effect on Liver Iron Concentration, Liver Histology, and Clinical Progress  

Microsoft Academic Search

A prospective trial of continuous chelation therapy in children with homozygous thalassaemia on a high transfusion regimen was started in April 1966. The effect of treatment on iron concentration in the liver and on hepatic histology was examined in 49 biopsy specimens obtained from nine chelator-treated patients and nine control patients between April 1966 and April 1973.Chelation therapy was associated

Michael Barry; David M. Flynn; Elizabeth A. Letsky; R. A. Risdon

1974-01-01

371

Mechanistic Basis for Overcoming Platinum Resistance Using Copper Chelating Agents  

PubMed Central

Platinum (Pt)-based antitumor agents are widely used in cancer chemotherapy. Drug resistance is a major obstacle to the successful use of these agents because once drug resistance develops, other effective treatment options are limited. Recently, we have conducted a clinical trial using a copper (Cu)-lowering agent to overcome Pt drug resistance in ovarian cancer patients and the preliminary results are encouraging. In supporting this clinical study, using three pairs of cisplatin (cDDP)-resistant cell lines and two ovarian cancer cell lines derived from patients who had failed in Pt-based chemotherapy, we demonstrated that cDDP resistance associated with reduced expression of the high affinity copper transporter (hCtr1) which is also a cDDP transporter, can be preferentially re-sensitized by copper-lowering agents due to enhanced hCtr1 expression, as compared with their drug-sensitive counterparts. Such a preferential induction of hCtr1 expression in cDDP-resistant variants by Cu chelation can be explained by the mammalian Cu homeostasis regulatory mechanism. Enhanced cell-killing efficacy by a Cu-lowering agent was also observed in animal xenografts bearing cDDP-resistant cells. Finally, by analyzing a public gene expression dataset, we found that ovarian cancer patients with elevated levels of hCtr1 in their tumors, but not ATP7A and ATP7B, had more favorable outcomes after Pt-drug treatment than those expressing low hCtr1 levels. This study reveals the mechanistic basis for using Cu chelation to overcome cDDP resistance in clinical investigations. PMID:22914438

Liang, Zheng D.; Long, Yan; Tsai, Wen-Bin; Fu, Siqing; Kurzrock, Razelle; Gagea-Iurascu, Mihai; Zhang, Fan; Chen, Helen H.W.; Hennessy, Bryan T.; Mills, Gordon B.; Savaraj, Niramol; Kuo, Macus Tien

2012-01-01

372

Molecular Models of EDTA and Other Chelating Agents  

NSDL National Science Digital Library

Deirdre Bell-Oudry presents a variation on an old theme in her paper on using an indirect EDTA titration for sulfate analysis (1). EDTA and (often loosely) related species are this month's Featured Molecules.EDTA is a hexaprotic acid (H6Y2+) having the pKa values given in the featured paper (1). Figure 1 shows a distribution diagram for the EDTA system (2). At the pH of normal waters, the predominant species have one or both of the nitrogen atoms protonated.Complexation, however, requires that both nitrogens be deprotonated and it is generally assumed that the form that complexes with metal ions is Y4?. Structures of several forms of EDTA are included in the molecule collection (Figure 2). These structures are quite flexible having many conformations that are readily accessible at room temperature.An introduction to EDTA chemistry leads to broader questions of metal ion chelation or sequestration. Related chelating agents included in the molecule collection are EGTA, DCTA, NTA, BAPTA, and DTPA. Molecular dynamics and Hartree-Fock calculations on BAPTA (Figure 2) confirm that many conformations, ranging from those with the phenyl rings parallel to one another, to more elongated forms, are essentially isoenergetic in room temperature aqueous solution (3).Also included in the molecule collection are several crown ethers, an isophore (nonactin), and a cryptand. These not only provide students with a glimpse of the types of molecules being employed for metal ion sequestration but open a wide range of topics of current research in a variety of areas of inorganic, industrial, environmental, and biological chemistry.

373

EDTA chelation effects on urinary losses of cadmium, calcium, chromium, cobalt, copper, lead, magnesium, and zinc.  

PubMed

The efficacy of a chelating agent in binding a given metal in a biological system depends on the binding constants of the chelator for the particular metals in the system, the concentration of the metals, and the presence and concentrations of other ligands competing for the metals in question. In this study, we make a comparison of the in vitro binding constants for the chelator, ethylenediaminetetraacetic acid, with the quantitative urinary excretion of the metals measured before and after EDTA infusion in 16 patients. There were significant increases in lead, zinc, cadmium, and calcium, and these increases roughly corresponded to the expected relative increases predicted by the EDTA-metal-binding constants as measured in vitro. There were no significant increases in urinary cobalt, chromium, or copper as a result of EDTA infusion. The actual increase in cobalt could be entirely attributed to the cobalt content of the cyanocobalamin that was added to the infusion. Although copper did increase in the post-EDTA specimens, the increase was not statistically significant. In the case of magnesium, there was a net retention of approximately 85% following chelation. These data demonstrate that EDTA chelation therapy results in significantly increased urinary losses of lead, zinc, cadmium, and calcium following EDTA chelation therapy. There were no significant changes in cobalt, chromium, or copper and a retention of magnesium. These effects are likely to have significant effects on nutrient concentrations and interactions and partially explain the clinical improvements seen in patients undergoing EDTA chelation therapy. PMID:11794513

Waters, R S; Bryden, N A; Patterson, K Y; Veillon, C; Anderson, R A

2001-12-01

374

Fabrication and characterization of the nano-composite of whey protein hydrolysate chelated with calcium.  

PubMed

The nano-composites of whey protein hydrolysate (WPH) chelated with calcium were fabricated in aqueous solution at 30 °C for 20 min, with the ratio of hydrolysate to calcium 15?:?1 (w/w). UV scanning spectroscopy, fluorescent spectroscopy, Fourier transform infrared spectroscopy, dynamic light scattering and atomic force microscopy were applied to characterize the structure of the WPH-calcium chelate. The nano-composites showed the successful incorporation of calcium into the WPH, indicating the interaction between calcium and WPH. The chelation of calcium ions to WPH caused molecular folding and aggregation which led to the formation of a WPH-calcium chelate of nanoparticle size, and the principal sites of calcium-binding corresponded to the carboxyl groups and carbonyl groups of WPH. The WPH-calcium chelate demonstrated excellent stability and absorbability under both acidic and basic conditions, which was beneficial for calcium absorption in the gastrointestinal tract of the human body. Moreover, the calcium absorption of the WPH-calcium chelate on Caco-2 cells was significantly higher than those of calcium gluconate and CaCl2in vitro, suggesting the possible increase in calcium bioavailability. The findings suggest that the WPH-calcium chelate has the potential in making dietary supplements for improving bone health of the human body. PMID:25588126

Xixi, Cai; Lina, Zhao; Shaoyun, Wang; Pingfan, Rao

2015-03-11

375

Warfarin modulates the nitrite reductase activity of ferrous human serum heme-albumin.  

PubMed

Human serum heme-albumin (HSA-heme-Fe) displays reactivity and spectroscopic properties similar to those of heme proteins. Here, the nitrite reductase activity of ferrous HSA-heme-Fe [HSA-heme-Fe(II)] is reported. The value of the second-order rate constant for the reduction of [Formula: see text] to NO and the concomitant formation of nitrosylated HSA-heme-Fe(II) (i.e., k on) is 1.3 M(-1) s(-1) at pH 7.4 and 20 °C. Values of k on increase by about one order of magnitude for each pH unit decrease between pH 6.5 to 8.2, indicating that the reaction requires one proton. Warfarin inhibits the HSA-heme-Fe(II) reductase activity, highlighting the allosteric linkage between the heme binding site [also named the fatty acid (FA) binding site 1; FA1] and the drug-binding cleft FA2. The dissociation equilibrium constant for warfarin binding to HSA-heme-Fe(II) is (3.1 ± 0.4) × 10(-4) M at pH 7.4 and 20 °C. These results: (1) represent the first evidence for the [Formula: see text] reductase activity of HSA-heme-Fe(II), (2) highlight the role of drugs (e.g., warfarin) in modulating HSA(-heme-Fe) functions, and (3) strongly support the view that HSA acts not only as a heme carrier but also displays transient heme-based reactivity. PMID:24037275

Ascenzi, Paolo; Tundo, Grazia R; Fanali, Gabriella; Coletta, Massimo; Fasano, Mauro

2013-12-01

376

Reciprocal allosteric modulation of carbon monoxide and warfarin binding to ferrous human serum heme-albumin.  

PubMed

Human serum albumin (HSA), the most abundant protein in human plasma, could be considered as a prototypic monomeric allosteric protein, since the ligand-dependent conformational adaptability of HSA spreads beyond the immediate proximity of the binding site(s). As a matter of fact, HSA is a major transport protein in the bloodstream and the regulation of the functional allosteric interrelationships between the different binding sites represents a fundamental information for the knowledge of its transport function. Here, kinetics and thermodynamics of the allosteric modulation: (i) of carbon monoxide (CO) binding to ferrous human serum heme-albumin (HSA-heme-Fe(II)) by warfarin (WF), and (ii) of WF binding to HSA-heme-Fe(II) by CO are reported. All data were obtained at pH 7.0 and 25°C. Kinetics of CO and WF binding to the FA1 and FA7 sites of HSA-heme-Fe(II), respectively, follows a multi-exponential behavior (with the same relative percentage for the two ligands). This can be accounted for by the existence of multiple conformations and/or heme-protein axial coordination forms of HSA-heme-Fe(II). The HSA-heme-Fe(II) populations have been characterized by resonance Raman spectroscopy, indicating the coexistence of different species characterized by four-, five- and six-coordination of the heme-Fe atom. As a whole, these results suggest that: (i) upon CO binding a conformational change of HSA-heme-Fe(II) takes place (likely reflecting the displacement of an endogenous ligand by CO), and (ii) CO and/or WF binding brings about a ligand-dependent variation of the HSA-heme-Fe(II) population distribution of the various coordinating species. The detailed thermodynamic and kinetic analysis here reported allows a quantitative description of the mutual allosteric effect of CO and WF binding to HSA-heme-Fe(II). PMID:23555601

Bocedi, Alessio; De Sanctis, Giampiero; Ciaccio, Chiara; Tundo, Grazia R; Di Masi, Alessandra; Fanali, Gabriella; Nicoletti, Francesco P; Fasano, Mauro; Smulevich, Giulietta; Ascenzi, Paolo; Coletta, Massimo

2013-01-01

377

Phenazine-1-Carboxylic Acid Promotes Bacterial Biofilm Development via Ferrous Iron Acquisition?†  

PubMed Central

The opportunistic pathogen Pseudomonas aeruginosa forms biofilms, which render it more resistant to antimicrobial agents. Levels of iron in excess of what is required for planktonic growth have been shown to promote biofilm formation, and therapies that interfere with ferric iron [Fe(III)] uptake combined with antibiotics may help treat P. aeruginosa infections. However, use of these therapies presumes that iron is in the Fe(III) state in the context of infection. Here we report the ability of phenazine-1-carboxylic acid (PCA), a common phenazine made by all phenazine-producing pseudomonads, to help P. aeruginosa alleviate Fe(III) limitation by reducing Fe(III) to ferrous iron [Fe(II)]. In the presence of PCA, a P. aeruginosa mutant lacking the ability to produce the siderophores pyoverdine and pyochelin can still develop into a biofilm. As has been previously reported (P. K. Singh, M. R. Parsek, E. P. Greenberg, and M. J. Welsh, Nature 417:552-555, 2002), biofilm formation by the wild type is blocked by subinhibitory concentrations of the Fe(III)-binding innate-immunity protein conalbumin, but here we show that this blockage can be rescued by PCA. FeoB, an Fe(II) uptake protein, is required for PCA to enable this rescue. Unlike PCA, the phenazine pyocyanin (PYO) can facilitate biofilm formation via an iron-independent pathway. While siderophore-mediated Fe(III) uptake is undoubtedly important at early stages of infection, these results suggest that at later stages of infection, PCA present in infected tissues may shift the redox equilibrium between Fe(III) and Fe(II), thereby making iron more bioavailable. PMID:21602354

Wang, Yun; Wilks, Jessica C.; Danhorn, Thomas; Ramos, Itzel; Croal, Laura; Newman, Dianne K.

2011-01-01

378

Reciprocal Allosteric Modulation of Carbon Monoxide and Warfarin Binding to Ferrous Human Serum Heme-Albumin  

PubMed Central

Human serum albumin (HSA), the most abundant protein in human plasma, could be considered as a prototypic monomeric allosteric protein, since the ligand-dependent conformational adaptability of HSA spreads beyond the immediate proximity of the binding site(s). As a matter of fact, HSA is a major transport protein in the bloodstream and the regulation of the functional allosteric interrelationships between the different binding sites represents a fundamental information for the knowledge of its transport function. Here, kinetics and thermodynamics of the allosteric modulation: (i) of carbon monoxide (CO) binding to ferrous human serum heme-albumin (HSA-heme-Fe(II)) by warfarin (WF), and (ii) of WF binding to HSA-heme-Fe(II) by CO are reported. All data were obtained at pH 7.0 and 25°C. Kinetics of CO and WF binding to the FA1 and FA7 sites of HSA-heme-Fe(II), respectively, follows a multi-exponential behavior (with the same relative percentage for the two ligands). This can be accounted for by the existence of multiple conformations and/or heme-protein axial coordination forms of HSA-heme-Fe(II). The HSA-heme-Fe(II) populations have been characterized by resonance Raman spectroscopy, indicating the coexistence of different species characterized by four-, five- and six-coordination of the heme-Fe atom. As a whole, these results suggest that: (i) upon CO binding a conformational change of HSA-heme-Fe(II) takes place (likely reflecting the displacement of an endogenous ligand by CO), and (ii) CO and/or WF binding brings about a ligand-dependent variation of the HSA-heme-Fe(II) population distribution of the various coordinating species. The detailed thermodynamic and kinetic analysis here reported allows a quantitative description of the mutual allosteric effect of CO and WF binding to HSA-heme-Fe(II). PMID:23555601

Bocedi, Alessio; De Sanctis, Giampiero; Ciaccio, Chiara; Tundo, Grazia R.; Di Masi, Alessandra; Fanali, Gabriella; Nicoletti, Francesco P.; Fasano, Mauro; Smulevich, Giulietta; Ascenzi, Paolo; Coletta, Massimo

2013-01-01

379

Computational methods for intramolecular electron transfer in a ferrous-ferric iron complex  

SciTech Connect

The limitations of common theoretical and molecular computational approaches for predicting electron transfer quantities were assessed, using an archetypal bridged ferrous-ferric electron transfer system in aqueous solution. The basis set effect on the magnitude of the electronic coupling matrix element computed using the quasi-diabatic method was carefully examined, and it was found that the error related to a poor basis set could exceed the thermal energy at room temperature. A range of approaches to determining the external (solvent) reorganization energy were also investigated. Significant improvements from the Marcus continuum model can be obtained by including dipolar Born-Kirkwood-Onsager correction. In this regard we also found that Klamt’s Conductor-Like Screening Model (COSMO) yields estimations of the external reorganization energy similar to those obtained with explicit solvent molecular dynamics simulations, if the fast-frequency modes are neglected, which makes it an attractive alternative to laborious umbrella sampling simulations. As expected, dielectric saturation observed in the first solvation shell decreases the curvature of the potential energy surface, but it nonetheless remains a quadratic function of the reaction coordinate. The linearity of solvent response to the charge redistribution was assessed by analyzing the energy gap autocorrelation function as well as the solvent density and dipole moment fluctuations. Molecular dynamics was also used to evaluate the sign and magnitude of the solvent reorganization entropy, to determine its effect on the predicted electron transfer rate. Finally, we present a simple way of estimating the vibration frequency along the reaction coordinate, which also enables prediction of the mass dependent isotopic signature of electron-transfer reactions.

Zarzycki, Piotr P.; Kerisit, Sebastien N.; Rosso, Kevin M.

2011-07-29

380

Structural analysis of metastable pseudobrookite ferrous titanium oxides with neutron diffraction and Mossbauer spectroscopy  

SciTech Connect

Four synthetic iron titanium oxides with the pseudobrookite (AB{sub 2}O{sub 5}, Cmcm, Z = 4) structure have been prepared and characterized by neutron diffraction and zero-field, natural abundance {sup 57}Fe Mossbauer effect spectroscopy (MES). The combination of the element specificity of MES with the different neutron scattering lengths of Ti and Fe ({minus}0.33 and 0.95 {times} 10{sup {minus}12} cm, respectively) offers a unique opportunity to distinguish between cation distributions on the two (A and B) sites. Two of the samples have been prepared in low temperature experiments (quenched from 1,200{degree}C) and have the stoichiometry FeTi{sub 2}O{sub 5}, and Fe{sub .6}Mg{sub .6}Ti{sub 1.8}O{sub 5}. The third and fourth samples are commercial iron titanium oxides prepared by the reduction of ilmenite ore with carbon above 1,700{degree}C. The stoichiometries of these samples are Mn{sub 0.05}Fe{sub 0.33}Ti{sub 2.52}O{sub 5} and Fe{sub .33}Mg{sub .31}Ti{sub 2.36}O{sub 5}. Results from these experiments indicate that for each of these samples the B site is predominantly (> 65%) occupied by Ti, while the A site contains a mixture of Ti, Fe, and/or Mg. However, only at higher temperatures (> 1,700{degree}C) is the B site devoid of ferrous cations.

Teller, R.G.; Antonio, M.R. (BP Research, Cleveland, OH (USA)); Grau, A.E.; Gueguin, M. (QIT-Fer et Titane Inc., Sorel, Quebec (Canada)); Kostiner, E. (Univ. of Connecticut, Storrs (USA))

1990-10-01

381

Spin-forbidden ligand binding to the ferrous-heme group: ab initio and DFT studies.  

PubMed

The potential energy surfaces (PESs) and associated energy barriers that characterize the spin-forbidden recombination reactions of the gas-phase ferrous deoxy-heme group with CO, NO, and H2O ligands have been calculated using density functional theory (DFT). The bond energy for binding of O2 has also been calculated. Extensive large basis set CCSD(T) calculations on two small models of the heme group have been used to calibrate the accuracy of different DFT functionals for treating these systems. Pure functionals are shown to overestimate the stability of the low-spin forms of the deoxy-heme model, and to overestimate the binding energy of H2O and CO, whereas hybrid functionals such as B3PW91 and B3LYP yield accurate results. Accordingly, the latter functionals have been used to explore the PESs for binding. CO binding is found to involve a significant barrier of ca. 3 kcal mol-1 due to the need to change from the deoxy-heme quintet ground state to the bound singlet state. Binding of water does not involve a barrier, but the resulting bond is weak and may be further weakened in the protein environment, which should explain why water binding is not usually observed in heme proteins such as myoglobin. NO binding involves a low barrier, which is consistent with observed rapid geminate recombination. The calculated bond energies are in good agreement with previous reported values and in fair agreement with experiment for CO and O2. The value for NO is significantly lower than the experimentally derived bond energy, suggesting that B3LYP is less accurate in this case. PMID:17249828

Strickland, Nikki; Harvey, Jeremy N

2007-02-01

382

Effect of ferric and ferrous iron addition on phosphorus removal and fouling in submerged membrane bioreactors.  

PubMed

The effect of continuously dosing membrane bioreactors (MBRs) with ferric chloride (Fe(III)) and ferrous sulphate (Fe(II)) on phosphorus (P) removal and membrane fouling is investigated here. Influent phosphorus concentrations of 10 mg/L were consistently reduced to effluent concentrations of less than 0.02 mg/L and 0.03-0.04 mg/L when an Fe(III)/P molar ratio of 4.0 and Fe/P molar ratio (for both Fe(II) and Fe(III)) of 2.0 were used, respectively. In comparison, effluent concentrations did not decrease below 1.35 mg/L in a control reactor to which iron was not added. The concentrations of supernatant organic compounds, particularly polysaccharides, were reduced significantly by iron addition. The sub-critical fouling time (tcrit) after which fouling becomes much more severe was substantially shorter with Fe(III) dosing (672 h) than with Fe(II) dosing (1200-1260 h) at Fe/P molar ratios of 2.0 while the control reactor (no iron dosing) exhibited a tcrit of 960 h. Not surprisingly, membrane fouling was substantially more severe at Fe/P ratios of 4. Fe(II) doses yielding Fe/P molar ratios of 2 or less with dosing to the aerobic chamber were found to be optimal in terms of P removal and fouling mitigation performance. In long term operation, however, the use of iron for maintaining appropriately low effluent P concentrations results in more severe irreversible fouling necessitating the application of an effective membrane cleaning regime. PMID:25482913

Zhang, Zhenghua; Wang, Yuan; Leslie, Greg L; Waite, T David

2015-02-01

383

Isomerism in Benzyl-DOTA Derived Bifunctional Chelators: Implications for Molecular Imaging.  

PubMed

The bifunctional chelator IB-DOTA has found use in a range of biomedical applications given its ability to chelate many metal ions, but in particular the lanthanide(III) ions. Gd(3+) in particular is of interest in the development of new molecular imaging agents for MRI and is highly suitable for chelation by IB-DOTA. Given the long-term instability of the aryl isothiocyanate functional group we have used the more stable nitro derivative (NB-DOTA) to conduct a follow-up study of some of our previous work on the coordination chemistry of chelates of these BFCs. Using a combination of NMR and HPLC to study the Eu(3+) and Yb(3+) chelates of NB-DOTA, we have demonstrated that this ligand will produce two discrete regioisomeric chelates at the point at which the metal ion is introduced into the BFC. These regioisomers are defined by the position of the benzylic substituent on the macrocyclic ring: adopting an equatorial position either at the corner or the side of the [3333] ring conformation. These regioisomers are incapable of interconversion and are distinct, separate structures with different SAP/TSAP ratios. The side isomer exhibits an increased population of the TSAP isomer, pointing to more rapid water exchange kinetics in this regioisomer. This has potential ramifications for the use of these two regioisomers of Gd(3+)-BFC chelates in MRI applications. We have also found that, remarkably, there is little or no freedom of rotation about the first single bond extending from the macrocyclic ring to the benzylic substituent. Since this is the linkage through which the chelate is conjugated to the remainder of the molecular imaging probe, this result implies that there may be reduced local rotation of the Gd(3+) chelate within a molecular imaging probe. This implies that this type of BFC could exhibit higher relaxivities than other types of BFC. PMID:25635382

Payne, Katherine M; Woods, Mark

2015-02-18

384

Alteration of tissue disposition of cadmium by chelating agents. [Mice; rats  

SciTech Connect

The effect of several chelating agents (diethyldithiocarbamic acid, DDC; nitrilotriacetic acid, NTA; 2,3-dimercaptopropanol, BAL; d,l-penicillamine, PEN; 2,3-dimercaptosuccinic acid, DMSA; ethylenediaminetetraacetic acid, EDTA; and diethylenetriaminepentaacetic acid, DTPA) on the toxicity, distribution and excretion of cadmium (Cd) was determined in mice. When chelators were administered immediately after Cd, significant increases in survival were noted after treatment with DMSA, EDTA, and DTPA. DTPA, followed by EDTA and then DMSA, were consistently the most effective in decreasing the tissue concentrations of Cd and increasing the excretion of Cd. NTA, BAL, DDC and PEN had no beneficial effects. To determine the role of MT in the acute decrease in chelator efficacy following Cd poisoning, rats were injected IV with Cd followed by DTPA at various times after Cd. Although DTPA reduced Cd content in the various organs when given immediately after Cd, the chelator was ineffective at all later times. Increases in hepatic and renal metallothionein (MT) did not occur until 2 hr after Cd, and did not coincide with the earlier drop in chelator efficacy. Blockade of MT synthesis by actinomycin D failed to eliminate this decreased DTPA effectiveness. Therefore, it appears that MT does not play an important role in the acute decrease in efficacy of chelation therapy for Cd poisoning. The effect of repeated daily administration of chelators on the distribution and excretion of Cd was studied by administering chelators daily for 5 days starting 48 hr after Cd. DTPA, EDTA, DMSA and BAL significantly increased the urinary elimination of Cd. Thus, mobilization of Cd into urine occurs with repeated chelation therapy, which may decrease tissue concentrations of Cd and reduce the toxicity of the metal. 4 references, 15 figures, 2 tables.

Klaassen, C.D.; Waalkes, M.P.; Cantilena, L.R. Jr.

1984-03-01

385

Rapid anaerobic benzene oxidation with a variety of chelated Fe(III) forms  

SciTech Connect

Techniques for stimulating aromatic hydrocarbon degradation in anaerobic portions of contaminated aquifers could be helpful in restoring polluted groundwater. Some studies have suggested that chelated Fe (III) might be an alternative electron acceptor that could be used instead of o2 for the bioremediation of aquifers contaminated with aromatic hydrocarbons. However, for this to be feasible an appropriate form of chelated Fe(III) that can be released into the environment must be identifed. Objections to the use of NTA have been raised because it may be carcinogenic at extremely high concentrations. This study evaluated the ability of other Fe(III) chelators to stimulate benzene degradation. 24 refs., 3 figs.

Lovley, D.R. [Univ. of Massachusetts, Amherst, MA (United States); Woodward, J.C. [Geological Survey, Reston, VA (United States); Chapelle, F.H. [Geological Survey, Columbia, SC (United States)

1996-01-01

386

(Bifunctional chelates of Rh-105, Au-199, and other metallic radionuclides as potential radiotherapeutic agents)  

SciTech Connect

Progress during this period is reported under the following headings: Diethylenetriamine based and related bifunctional chelating agents and their complexation with Rh-105, Au-198, Pd-109, cu-67, In-111, and Co-57; studies of Pd-109, Rh-105 and Tc-99m with bifunctional chelates based on phenylenediamine; establishment of an appropriate protein assay method for conjugated proteins; studies of new bifunctional Bi, Tri and tetradentate amine oxime ligands with Rh-105; IgG and antibody B72.3 conjugation studies by HPLC Techniques with bifunctional metal chelates; and progress on ligand systems for Au(III).

Not Available

1991-01-01

387

[Bifunctional chelates of Rh-105, Au-199, and other metallic radionuclides as potential radiotherapeutic agents  

SciTech Connect

Progress during this period is reported under the following headings: Diethylenetriamine based and related bifunctional chelating agents and their complexation with Rh-105, Au-198, Pd-109, cu-67, In-111, and Co-57; studies of Pd-109, Rh-105 and Tc-99m with bifunctional chelates based on phenylenediamine; establishment of an appropriate protein assay method for conjugated proteins; studies of new bifunctional Bi, Tri and tetradentate amine oxime ligands with Rh-105; IgG and antibody B72.3 conjugation studies by HPLC Techniques with bifunctional metal chelates; and progress on ligand systems for Au(III).

Not Available

1991-12-31

388

PhysicoChemical Studies on Some Tetragonal Nickel(II) Chelates  

Microsoft Academic Search

Nickel(II) chelates of Schiff bases derived from 4-formyl-1,3-diphenyl-2-pyrazolin-5-one and 4-formyl-1-phenyl-3-methyl-2-pyrazolin-5-one with aniline, m-toluidine, p-toluidine, m-chloroaniline, p-chloroaniline and ethanolamine have been prepared. Analytical data suggest a 1:2 (metal:ligand) ratio for all the chelates. All the chelates are non-electrolytic in nature, and have an octahedral configuration as inferred from magnetic susceptibility, infrared and diffuse reflectance spectral studies.

H. K. Soni; J. R. Shah

1985-01-01

389

Design, synthesis, and evaluation of polyhydroxamate chelators for selective complexation of actinides  

SciTech Connect

Specific chelating polymers targeted for actinides have much relevance to problems involving remediation of nuclear waste. Goal is to develop polymer supported, ion specific extraction systems for removing actinides and other hazardous metal ions from wastewaters. This is part of an effort to develop chelators for removing actinide ions such as Pu from soils and waste streams. Selected ligands are being attached to polymeric backbones to create novel chelating polymers. These polymers and other water soluble and insoluble polymers have been synthesized and are being evaluated for ability to selectively remove target metal ions from process waste streams.

Gopalan, A.; Jacobs, H.; Koshti, N.; Stark, P.; Huber, V.; Dasaradhi, L.; Caswell, W. [New Mexico State Univ., Las Cruces, NM (United States); Smith, P.; Jarvinen, G. [Los Alamos National Lab., NM (United States)

1995-08-01

390

In vitro evaluation of iron solubility and dialyzability of various iron fortificants and of iron-fortified milk products targeted for infants and toddlers.  

PubMed

The objectives of the present study were: to compare the solubility and dialyzability of various iron fortificants (iron pyrophosphate, ferrous bis-glycinate, ferrous gluconate, ferrous lactate, ferrous sulfate) added, in the presence of ascorbic acid, to pasteurized milk samples produced under laboratory conditions; and to compare the solubility and dialyzability of iron in commercial pasteurized, UHT and condensed milk products available in the Greek market fortified with various vitamins and minerals including iron and targeted towards infants (6-12 months old) and toddlers. Iron solubility and dialyzability were determined using a simulated gastrointestinal digestive system. Ferrous dialyzable iron (molecular weight lower than 8000) was used as an index for prediction of iron bioavailability. Ferrous dialyzable iron in pasteurized milk samples fortified with iron pyrophosphate, ferrous lactate and ferrous bis-glycinate was higher (P < 0.05) than that in milk samples fortified with ferrous sulfate and ferrous gluconate. In commercial liquid pasteurized or UHT milk products, formation of ferrous dialyzable iron in products fortified with ferrous lactate was not different (P > 0.05) from those fortified with ferrous sulfate. Ferrous dialyzable iron in four condensed commercial milk products was higher (P < 0.05) than the corresponding values of the liquid UHT milk samples fortified with the same fortificant (ferrous sulfate). Ferrous dialyzable iron was higher (P < 0.05) in products targeted for infants compared with those targeted for toddlers. In conclusion, the type of iron source, milk processing and the overall product composition affect formation of ferrous dialyzable iron and may determine the success and effectiveness of iron fortification of milk. PMID:16096139

Kapsokefalou, Maria; Alexandropoulou, Isidora; Komaitis, Michail; Politis, Ioannis

2005-06-01

391

Selective divalent copper chelation for the treatment of diabetes mellitus.  

PubMed

Oxidative stress and mitochondrial dysfunction have been identified by many workers as key pathogenic mechanisms in ageing-related metabolic, cardiovascular and neurodegenerative diseases (for example diabetes mellitus, heart failure and Alzheimer's disease). However, although numerous molecular mechanisms have been advanced to account for these processes, their precise nature remains obscure. This author has previously suggested that, in such diseases, these two mechanisms are likely to occur as manifestations of a single underlying disturbance of copper regulation. Copper is an essential but highly-toxic trace metal that is closely regulated in biological systems. Several rare genetic disorders of copper homeostasis are known in humans: these primarily affect various proteins that mediate intracellular copper transport processes, and can lead either to tissue copper deficiency or overload states. These examples illustrate how impaired regulation of copper transport pathways can cause organ damage and provide important insights into the impact of defects in specific molecular processes, including those catalyzed by the copper-transporting ATPases, ATP7A (mutated in Menkes disease), ATP7B (Wilson's disease), and the copper chaperones such as those for cytochrome c oxidase, SCO1 and SCO2. In diabetes, impaired copper regulation manifests as elevations in urinary CuII excretion, systemic chelatable-CuII and full copper balance, in increased pro-oxidant stress and defective antioxidant defenses, and in progressive damage to the blood vessels, heart, kidneys, retina and nerves. Linkages between dysregulated copper and organ damage can be demonstrated by CuII-selective chelation, which simultaneously prevents/reverses both copper dysregulation and organ damage. Pathogenic structures in blood vessels that contribute to binding and localization of catalytically-active CuII probably include advanced glycation end products (AGEs), as well as atherosclerotic plaque: the latter probably undergoes AGE-modification itself. Defective copper regulation mediates organ damage through two general processes that occur simultaneously in the same individual: elevation of CuII-mediated pro-oxidant stress and impairment of copper-catalyzed antioxidant defence mechanisms. This author has proposed that diabetes-evoked copper dysregulation is an important new target for therapeutic intervention to prevent/reverse organ damage in diabetes, heart failure, and neurodegenerative diseases, and that triethylenetetramine (TETA) is the first in a new class of anti-diabetic molecules, which function by targetting these copper-mediated pathogenic mechanisms. TETA prevents tissue damage and causes organ regeneration by acting as a highly-selective CuII chelator which suppresses copper-mediated oxidative stress and restores anti-oxidant defenses. My group has employed TETA in a comprehensive programme of nonclinical studies and proof-of-principle clinical trials, thereby characterizing copper dysregulation in diabetes and identifying numerous linked cellular and molecular mechanisms though which TETA exerts its therapeutic actions. Many of the results obtained in nonclinical models with respect to the molecular mechanisms of diabetic organ damage have not yet been replicated in patients' tissues so their applicability to the human disease must be considered as inferential until the results of informative clinical studies become available. Based on evidence from the studies reviewed herein, trientine is now proceeding into the later stages of pharmaceutical development for the treatment of heart failure and other diabetic complications. PMID:22455587

Cooper, G J S

2012-01-01

392

Evaluation of chelating agents for radioimmunotherapy with scandium-47  

SciTech Connect

Sc-47 has attractive properties [t{1/2} 3.35d, {beta}{sub max}:441 keV (68%), 601 keV (32%); {gamma} 159.4 keV (68%)] for radioimmunotherapy. Sc also displays favorable coordination chemistry for chelation attachment to antibodies. Due to chemical similarities to In and Y we have tested ligands with Sc-47 originally developed for use with In-111 or Y-90. The Scl-47 was produced with a fast neutron reaction Ti-47 (n,p). The radiochemical separation used cation exchange (AG-MP50) loaded with a 2% H{sub 2}O{sub 2} - 1 M H{sub 2}SO{sub 4} solution, followed by elution of Sc-47 with a 1 M NH{sub 4}{sub 2}SO{sub 4}/0.25 M H{sub 2}SO{sub 4} solution. Further separation and conversion of Sc to chloride form is achieved with a Chelex 100 column. No traces of Ti or Fe could be detected by spectrophotometric assay. Anti-CEA F(ab{prime});{sub 2} antibody conjugates of the following chelates were used for labeling studies: 4-isothiocyanato-cyclohexyl EDTA (4-ICE), N-hydroxysuccinimide ester of DOTA {l_angle}DOTA NHS{r_angle}, 2-{l_angle}p-SCN-Bz{r_angle}-6 methyl DTPA {l_angle}1B4MDTPA{r_angle} and conventional DTPA dianhydride. Labeling yields with Sc-47 were, 4-ICE 80%, DOTAQ-NHS 64%, 1B4MDTPA 98% and DTPA 62%. Serum stability of these preparations was essentially 100% out to 48 h except for DTPA (61%). The biodistribution {l_angle}% ID/g{r_angle} of these conjugates in human tumor xenografted nude mice {l_angle}LS-174% cells{r_angle} was compared. 4-ICE, DOTA-NHS and 1B4M-DTPA(15.4, 7.0, 7.0) but liver uptake was somewhat higher for DOTA-NHS than 4-ICE or 1B4M-DTPA (9.4, 5.8, 5.6). Generally faster whole body clearance for 1B4M-DTPA led to somewhat better tumor to organ ratios by 48 h. The poor stability of DTPA conjugate was evident with poor tumor uptake (12.4), high kidney (14.8), liver (17.1) and bone (3.6). We conclude that ligands which perform better with In-111 and Y-90 also give stable Sc-47 conjugates and their biodistributions are favorable for radioimmunotherapy.

Mausner, L.F.; Joshi, V.; Kolsky, K.L. [Brookhaven National Laboratory, Upton, NY (United States)] [and others

1995-05-01

393

Radiolabeled technetium chelates for use in renal function determinations  

DOEpatents

The present invention is directed to novel radiopharmaceutical imaging agents incorporating Tc-99m as a radiolabel. In particular, the novel imaging agents disclosed herein have relatively high renal extraction efficiencies, and hence are useful for conducting renal function imaging procedures. The novel Tc-99m compounds of a present invention have the following general formula: ##STR1## wherein X is S or N; and wherein Y is --H or wherein Y is ##STR2## and where R.sub.1 is --H, --CH.sub.3, or --CH.sub.2 CH.sub.3 ; R.sub.2 is --H, --CH.sub.2 CO.sub.2 H, --CH.sub.2 CONH.sub.2, --CH.sub.2 CH.sub.2 CO.sub.2 H, --CH.sub.2 CH.sub.2 CONH.sub.2, --CH.sub.3, --CH.sub.2 CH.sub.3, CH.sub.2 C.sub.6 H.sub.5, or --CH.sub.2 OH; and Z is --H, --CO.sub.2 H, --CONH.sub.2, --SO.sub.3 H, --SO.sub.2 NH.sub.2, or --CONHCH.sub.2 CO.sub.2 H; and the Tc is Tc-99m; and water-soluble salts thereof. Of the foregoing, the presently preferred Tc-99m compound of the present invention is Tc-99m-mercaptoacetylglycylglycylglycine (Tc-99m-MAGGG). The present invention is also directed to novel chelating agents that may be reacted with Tc-99m to form the foregoing compounds. Such novel chelating agents have the following general formula. ##STR3## where X and Y have the same definitions as above, and wherein Y' is --H.sub.2 when X is N, or wherein Y' is --H, or a suitable protective group such as --COCH.sub.3, --COC.sub.6 H.sub.5, --CH.sub.2 NHCOCH.sub.3, --COCF.sub.3, or --COCH.sub.2 OH when X is S. The present invention also provides methods for preparing and using the novel Tc-99m compounds.

Fritzberg, Alan (Edmonds, WA); Kasina, Sudhaker (Kirkland, WA); Johnson, Dennis L. (Las Cruces, NM)

1994-01-01

394

Radiolabeled technetium chelates for use in renal function determinations  

DOEpatents

The present invention is directed to novel radiopharmaceutical imaging agents incorporating Tc-99m as a radiolabel. In particular, the novel imaging agents disclosed herein have relatively high renal extraction efficiencies, and hence are useful for conducting renal function imaging procedures. The novel Tc-99m compounds of a present invention have the following general formula: ##STR1## wherein X is S or N; and wherein Y is--H or wherein Y is ##STR2## and where R.sub.1 is --H, --CH.sub.3, or --CH.sub.2 CH.sub.3 ; R.sub.2 is --H, --CH.sub.2 CO.sub.2 H, --CH.sub.2 CONH.sub.2, --CH.sub.2 CH.sub.2 CO.sub.2 H, --CH.sub.2 CH.sub.2 CONH.sub.2, --CH.sub.3, --CH.sub.2 CH.sub.3, CH.sub.2 C.sub.6 H.sub.5, or --CH.sub.2 OH; and Z is --H, --CO.sub.2 H, --CONH.sub.2, --SO.sub.3 H, --SO.sub.2 NH.sub.2, or --CONHCH.sub.2 CO.sub.2 H; and the Tc is Tc-99m; and water-soluble salts thereof. Of the foregoing, the presently preferred Tc-99m compound of the present invention is Tc-99m-mercaptoacetylglycylglycylglycine (Tc-99m-MAGGG). The present invention is also directed to novel chelating agents that may be reacted with Tc-99m to form the foregoing compounds. Such novel chelating agents have the following general formula. ##STR3## where X and Y have the same definitions as above, and wherein Y' is --H.sub.2 when X is N, or wherein Y' is --H, or a suitable protective group such as --COCH.sub.3, --COC.sub.6 H.sub.5, --CH.sub.2 NHCOCH.sub.3, --COCF.sub.3, or --COCH.sub.2 OH when X is S. The present invention also provides methods for preparing and using the novel Tc-99m compounds.

Fritzberg, Alan (Edmonds, WA); Kasina, Sudhakar (Kirkland, WA); Johnson, Dennis L. (Las Cruces, NM)

1990-01-01

395

Enhancement of bismuth antibacterial activity with lipophilic thiol chelators.  

PubMed Central

The antibacterial properties of bismuth are greatly enhanced when bismuth is combined with certain lipophilic thiol compounds. Antibacterial activity was enhanced from 25- to 300-fold by the following seven different thiols, in order of decreasing synergy: 1,3-propanedithiol, dimercaprol (BAL), dithiothreitol, 3-mercapto-2-butanol, beta-mercaptoethanol, 1-monothioglycerol, and mercaptoethylamine. The dithiols produced the greatest synergy with bismuth at optimum bismuth-thiol molar ratios of from 3:1 to 1:1. The monothiols were generally not as synergistic and required molar ratios of from 1:1 to 1:4 for optimum antibacterial activity. The most-active mono- or dithiols were also the most soluble in butanol. The intensity of the yellow formed by bismuth-thiol complexes reflected the degree of chelation and correlated with antibacterial potency at high molar ratios. The bismuth-BAL compound (BisBAL) was active against most bacteria, as assessed by broth dilution, agar diffusion, and agar dilution analyses. Staphylococci (MIC, 5 to 7 microM Bi3+) and Helicobacter pylori (MIC, 2.2 microM) were among the most sensitive bacteria. Gram-negative bacteria were sensitive (MIC, < 17 microM). Enterococci were relatively resistant (MIC, 63 microM Bi3+). The MIC range for anaerobes was 15 to 100 microM Bi3+, except for Clostridium difficile (MIC, 7.5 microM). Bactericidal activity averaged 29% above the MIC. Bactericidal activity increased with increasing pH and/or increasing temperature. Bismuth-thiol solubility, stability, and antibacterial activity depended on pH and the bismuth-thiol molar ratio. BisBAL was stable but ineffective against Escherichia coli at pH 4. Activity and instability (reactivity) increased with increasing alkalinity. BisBAL was acid soluble at a molar ratio of greater than 3:2 and alkaline soluble at a molar ratio of less than 2:3. In conclusion, certain lipophilic thiol compounds enhanced bismuth antibacterial activity against a broad spectrum of bacteria. The activity, solubility, and stability of BisBAL were strongly dependent on the pH, temperature, and molar ratio. Chelation of bismuth with certain thiol agents enhanced the solubility and lipophilicity of this cationic heavy metal, thereby significantly enhancing its potency and versatility as an antibacterial agent. PMID:9257744

Domenico, P; Salo, R J; Novick, S G; Schoch, P E; Van Horn, K; Cunha, B A

1997-01-01

396

O{sub 2}-mediated oxidation of ferrous nitrosylated human serum heme-albumin is limited by nitrogen monoxide dissociation  

SciTech Connect

Research highlights: {yields} Human serum heme-albumin displays globin-like properties. {yields} O{sub 2}-mediated oxidation of ferrous nitrosylated human serum heme-albumin. {yields} Allosteric modulation of human serum heme-albumin reactivity. {yields} Rifampicin is an allosteric effector of human serum heme-albumin. {yields} Human serum heme-albumin is a ROS and NOS scavenger. -- Abstract: Human serum heme-albumin (HSA-heme-Fe) displays globin-like properties. Here, kinetics of O{sub 2}-mediated oxidation of ferrous nitrosylated HSA-heme-Fe (HSA-heme-Fe(II)-NO) is reported. Values of the first-order rate constants for O{sub 2}-mediated oxidation of HSA-heme-Fe(II)-NO (i.e., for ferric HSA-heme-Fe formation) and for NO dissociation from HSA-heme-Fe(II)-NO (i.e., for NO replacement by CO) are k = 9.8 x 10{sup -5} and 8.3 x 10{sup -4} s{sup -1}, and h = 1.3 x 10{sup -4} and 8.5 x 10{sup -4} s{sup -1}, in the absence and presence of rifampicin, respectively, at pH = 7.0 and T = 20.0 {sup o}C. The coincidence of values of k and h indicates that NO dissociation represents the rate limiting step of O{sub 2}-mediated oxidation of HSA-heme-Fe(II)-NO. Mixing HSA-heme-Fe(II)-NO with O{sub 2} does not lead to the formation of the transient adduct(s), but leads to the final ferric HSA-heme-Fe derivative. These results reflect the fast O{sub 2}-mediated oxidation of ferrous HSA-heme-Fe and highlight the role of drugs in modulating allosterically the heme-Fe-atom reactivity.

Ascenzi, Paolo, E-mail: ascenzi@uniroma3.it [Interdepartmental Laboratory of Electron Microscopy, University Roma Tre, Via della Vasca Navale 79, I-00146 Roma (Italy) [Interdepartmental Laboratory of Electron Microscopy, University Roma Tre, Via della Vasca Navale 79, I-00146 Roma (Italy); National Institute for Infectious Diseases I.R.C.C.S. 'Lazzaro Spallanzani', Via Portuense 292, I-00149 Roma (Italy); Gullotta, Francesca; Gioia, Magda; Coletta, Massimo [Department of Experimental Medicine and Biochemical Sciences, University of Roma 'Tor Vergata', Via Montpellier 1, I-00133 Roma (Italy) [Department of Experimental Medicine and Biochemical Sciences, University of Roma 'Tor Vergata', Via Montpellier 1, I-00133 Roma (Italy); Interuniversity Consortium for the Research on the Chemistry of Metals in Biological Systems, Piazza Umberto I 1, I-87100 Bari (Italy); Fasano, Mauro [Department of Structural and Functional Biology, and Center of Neuroscience, University of Insubria, Via Alberto da Giussano 12a, I-21052 Busto Arsizio, VA (Italy)] [Department of Structural and Functional Biology, and Center of Neuroscience, University of Insubria, Via Alberto da Giussano 12a, I-21052 Busto Arsizio, VA (Italy)

2011-03-04

397

Chelating stability of an amphoteric chelating polymer flocculant with Cu(II), Pb(II), Cd(II), and Ni(II).  

PubMed

The absorption spectra of Cu(2+), Pb(2+), Cd(2+), and Ni(2+) chelates of an amphoteric chelating polymer flocculant (ACPF) were measured by ultraviolet spectrophotometry, and their compositions and stability constants (?) were calculated. ACPF exhibited three apparent absorption peaks at 204, 251, and 285 nm. The CSS(-) group of ACPF reacted with Cu(2+), Ni(2+), Pb(2+), and Cd(2+) to form ACPF-Cu(2+), ACPF-Ni(2+), ACPF-Pb(2+), and ACPF-Cd(2+) chelates, respectively, according to a molar ratio of 2:1. The maximum absorption peaks of ACPF-Cu(2+), ACPF-Ni(2+), ACPF-Pb(2+), and ACPF-Cd(2+) appeared at 319, 326, 310, and 313.5 nm, respectively. The maximum absorption peaks of the chelates showed significant red shifting compared with the absorption peaks of ACPF. The ? values of the ACPF-Cu(2+), ACPF-Pb(2+), ACPF-Cd(2+), and ACPF-Ni(2+) chelates were (1.37±0.35)×10(12), (3.26±0.39)×10(11), (2.05±0.27)×10(11), and (3.04±0.45)×10(10), respectively. The leaching rate of heavy metal ions from the chelating precipitates decreased with increasing pH. ACPF-Cu(2+), ACPF-Ni(2+), ACPF-Pb(2+), and ACPF-Cd(2+) were very stable at pH?5.6. Cu(2+), Ni(2+), Pb(2+), and Cd(2+) concentrations in the leaching liquors were lower than the corresponding limits specified by the Integrated Wastewater Discharge Standard of China. PMID:24144830

Liu, Lihua; Li, Yanhong; Liu, Xing; Zhou, Zhihua; Ling, Yulin

2014-01-24

398

Chelating stability of an amphoteric chelating polymer flocculant with Cu(II), Pb(II), Cd(II), and Ni(II)  

NASA Astrophysics Data System (ADS)

The absorption spectra of Cu2+, Pb2+, Cd2+, and Ni2+ chelates of an amphoteric chelating polymer flocculant (ACPF) were measured by ultraviolet spectrophotometry, and their compositions and stability constants (?) were calculated. ACPF exhibited three apparent absorption peaks at 204, 251, and 285 nm. The sbnd CSS- group of ACPF reacted with Cu2+, Ni2+, Pb2+, and Cd2+ to form ACPF-Cu2+, ACPF-Ni2+, ACPF-Pb2+, and ACPF-Cd2+ chelates, respectively, according to a molar ratio of 2:1. The maximum absorption peaks of ACPF-Cu2+, ACPF-Ni2+, ACPF-Pb2+, and ACPF-Cd2+ appeared at 319, 326, 310, and 313.5 nm, respectively. The maximum absorption peaks of the chelates showed significant red shifting compared with the absorption peaks of ACPF. The ? values of the ACPF-Cu2+, ACPF-Pb2+, ACPF-Cd2+, and ACPF-Ni2+ chelates were (1.37 ± 0.35) × 1012, (3.26 ± 0.39) × 1011, (2.05 ± 0.27) × 1011, and (3.04 ± 0.45) × 1010, respectively. The leaching rate of heavy metal ions from the chelating precipitates decreased with increasing pH. ACPF-Cu2+, ACPF-Ni2+, ACPF-Pb2+, and ACPF-Cd2+ were very stable at pH ? 5.6. Cu2+, Ni2+, Pb2+, and Cd2+ concentrations in the leaching liquors were lower than the corresponding limits specified by the Integrated Wastewater Discharge Standard of China.

Liu, Lihua; Li, Yanhong; Liu, Xing; Zhou, Zhihua; Ling, Yulin

2014-01-01

399

Highly Bright Avidin-based Affinity Probes Carrying Multiple Lanthanide Chelates  

PubMed Central

Lanthanide ion luminescence has a long lifetime enabling highly sensitive detection in time-gated mode. The sensitivity can be further increased by using multiple luminescent labels attached to a carrier molecule, which can be conjugated to an object of interest. We found that up to 30 lanthanide chelates can be attached to avidin creating highly bright constructs. These constructs with Eu3+ chelates display synergistic effect that enhance the brightness of heavily modified samples, while the opposite effect was observed for Tb3+ chelates thereby significantly reducing their light emission. This undesirable quenching of Tb3+ luminophores was completely suppressed by the introduction of an aromatic spacer between the chelate and the protein attachment site. The estimated detection limit for the conjugates is in the 10-14 – 10-15 M range. We demonstrated a high sensitivity for the new probes by using them to label living cells of bacterial and mammalian origin. PMID:23018156

Wirpsza, Laura; Pillai, Shyamala; Batish, Mona; Marras, Salvatore; Krasnoperov, Lev; Mustaev, Arkady

2012-01-01

400

The Management of Iron Chelation Therapy: Preliminary Data from a National Registry of Thalassaemic Patients  

PubMed Central

Thalassaemia and other haemoglobinopathies constitute an important health problem in Mediterranean countries, placing a tremendous emotional, psychological, and economic burden on their National Health systems. The development of new chelators in the most recent years had a major impact on the treatment of thalassaemia and on the quality of life of thalassaemic patients. A new initiative was promoted by the Italian Ministry of Health, establishing a Registry for thalassaemic patients to serve as a tool for the development of cost-effective diagnostic and therapeutic approaches and for the definition of guidelines supporting the most appropriate management of the iron-chelating therapy and a correct use of the available iron-chelating agents. This study represents the analysis of the preliminary data collected for the evaluation of current status of the iron chelation practice in the Italian thalassaemic population and describes how therapeutic interventions can widely differ in the different patients' age groups. PMID:21738864

Ceci, Adriana; Mangiarini, Laura; Felisi, Mariagrazia; Bartoloni, Franco; Ciancio, Angela; Capra, Marcello; D'Ascola, Domenico; Cianciulli, Paolo; Filosa, Aldo

2011-01-01

401

Association of antigens to ISCOMATRIX adjuvant using metal chelation leads to improved CTL responses.  

PubMed

The association of antigen with ISCOMATRIX trade mark adjuvant has been shown to be important for the optimal induction of cytotoxic T lymphocyte (CTL) responses. Here, we describe a simple broadly applicable method for associating recombinant proteins with hexa-histidine tags to ISCOMATRIX trade mark adjuvant utilising metal-affinity chelating interactions. The metal chelation binding step can be performed in a wide range of buffers, including commonly used denaturants such as urea, which makes it an ideal strategy for formulating proteins which are otherwise insoluble. Following association of protein with the chelating ISCOMATRIX trade mark adjuvant, the denaturant can be removed. Further, we show enhanced CTL responses with a protein-associated chelating ISCOMATRIX trade mark vaccine compared to a non-associated ISCOMATRIX trade mark vaccine. PMID:15364446

Malliaros, Jim; Quinn, Charles; Arnold, Frances H; Pearse, Martin J; Drane, Debbie P; Stewart, Trina J; Macfarlan, Roderick I

2004-09-28

402

Fast, Cell-Compatible Click Chemistry with Copper-Chelating Azides for Biomolecular Labeling  

E-print Network

Bring your own copper: Copper-chelating azides undergo much faster click reactions (CuAAC) than nonchelating azides under a variety of biocompatible conditions. This kinetic enhancement allows site-specific protein labeling ...

Uttamapinant, Chayasith

403

Bifunctional chelating agent for the design and development of site specific radiopharmaceuticals and biomolecule conjugation strategy  

DOEpatents

There is provided a method of labeling a biomolecule with a transition metal or radiometal in a site specific manner to produce a diagnostic or therapeutic pharmaceutical compound by synthesizing a P.sub.2 N.sub.2 -bifunctional chelating agent intermediate, complexing the intermediate with a radio metal or a transition metal, and covalently linking the resulting metal-complexed bifunctional chelating agent with a biomolecule in a site specific manner. Also provided is a method of synthesizing the --PR.sub.2 containing biomolecules by synthesizing a P.sub.2 N.sub.2 -bifunctional chelating agent intermediate, complexing the intermediate with a radiometal or a transition metal, and covalently linking the resulting radio metal-complexed bifunctional chelating agent with a biomolecule in a site specific manner. There is provided a therapeutic or diagnostic agent comprising a --PR.sub.2 containing biomolecule.

Katti, Kattesh V.; Prabhu, Kandikere R.; Gali, Hariprasad; Pillarsetty, Nagavara Kishore; Volkert, Wynn A.

2003-10-21

404

Enhanced Nucleophilic Fluorination and Radiofluorination of Organosilanes Appended with Potassium-Chelating Leaving Groups  

PubMed Central

Here we aimed to explore the feasibility of enhancing the fluorination of organosilanes by appending potassium-chelating groups to the substrates. For this purpose, eight organosilanes were prepared in which a linear or cyclic leaving group, with putative potassium-chelating ability, was attached covalently to a congested silicon atom via an ether linkage to serve as a potential nucleophilic assisting leaving group (NALG). Organosilicon-NALGs with expected strong potassium-chelating capability enhanced reactions with potassium fluoride in acetonitrile to produce organofluorosilanes without any need to separately add phase transfer reagent. Similar rate enhancements were also observed with cyclotron-produced [18F]fluoride ion (t1/2 = 109.7 min, ?+ = 97%) in the presence of potassium carbonate in MeCN-0.5% H2O. This study found that metal-chelating NALG units can accelerate fluorination and radiofluorination reactions at sterically crowded silicon atoms. PMID:24653526

Al-huniti, Mohammed H.; Lu, Shuiyu; Pike, Victor W.; Lepore, Salvatore D.

2014-01-01

405

CONTROL OF CHELATOR-BASED UPSETS IN SURFACE FINISHING SHOP WASTE WATER TREATMENT SYSTEMS  

EPA Science Inventory

Actual surface finishing shop examples are used to illustrate the use of process chemistry understanding and analyses to identify immediate, interim and permanent response options for industrial waste water treatment plant (IWTP) upset problems caused by chelating agents. There i...

406

Assessment of mapping exposed ferrous and ferric iron compounds using Skylab-EREP data. [Pisgah Crater, California  

NASA Technical Reports Server (NTRS)

The author has identified the following significant results. The S190B color photography is as useful as LANDSAT data for the mapping of color differences in the rocks and soils of the terrain. An S192 ratio of 0.79 - 0.89 and 0.93 - 1.05 micron bands produced an apparently successful delineation of ferrous, ferric, and other materials, in agreement with theory and ratio code studies. From an analysis of S191 data, basalt and dacite were separated on the basis of differences in spectral emissivity in the 8.3 - 12 micron region.

Vincent, R. (principal investigator); Wagner, H.; Pillars, W.; Bennett, C.

1976-01-01

407

The relation of fO?, ferric-ferrous ratio (R), and physical properties of four natural clinoamphiboles  

E-print Network

-magnetite-quartz (FM(}), and graphite-methane (CCH4) buffers at 650'C and 1 kb. Runs were also conducted at 500'C and 400'C and 1 kb to increase the understanding of amphibole stabi 1- ity limits. The ferric-ferrous ratio for each sample was determined using... the single dissolution technique of Fritz and Popp ( 1985). The effect of increasing R on physical properties, such as unit cell parameters and optical properties, of the amphiboles was determined. The unit cell parameters of each sample were determined...

Clowe, Celia Ann

1987-01-01

408

Chelating ability and biological activity of hesperetin Schiff base.  

PubMed

Hydrazone hesperetin Schiff base (HHSB) - N-[(±)-[5,7-dihydroxy-2-(3-hydroxy-4-methoxy-phenyl)chroman-4-ylidene]amino]benzamide has been synthesized and its crystal structure was determined. This compound was used for the formation of Cu(II) complexes in solid state and in solution which were characterized using different spectroscopic methods. The analyses of potentiometric titration curves revealed that monomeric and dimeric complexes of Cu(II) are formed above pH7. The ESI-MS (electrospray ionization-mass spectrometry) spectra confirmed their formation. The EPR and UV-visible spectra evidenced the involvement of oxygen and nitrogen atoms in Cu(II) coordination. Hydrazone hesperetin Schiff base can show keto-enol tautomerism and coordinate Cu(II) in the keto (O(-), N, Oket) and in the enolate form (O(-), N, O(-)enol). The semi-empirical molecular orbital method PM6 and DFT (density functional theory) calculations have revealed that the more stable form of the dimeric complex is that one in which the ligand is present in the enol form. The CuHHSB complex has shown high efficiency in the cleavage of plasmid DNA in aqueous solution, indicating its potential as chemical nuclease. Studies on DNA interactions, antimicrobial and cytotoxic activities have been undertaken to gain more information on the biological significance of HHSB and copper(II)-HHSB chelate species. PMID:25486205

Lodyga-Chruscinska, Elzbieta; Symonowicz, Marzena; Sykula, Anna; Bujacz, Anna; Garribba, Eugenio; Rowinska-Zyrek, Magdalena; Oldziej, Stanislaw; Klewicka, Elzbieta; Janicka, Magdalena; Krolewska, Karolina; Cieslak, Marcin; Brodowska, Katarzyna; Chruscinski, Longin

2015-02-01

409

mer and fac isomerism in tris chelate diimine metal complexes.  

PubMed

In this perspective, we highlight the issue of meridional (mer) and facial (fac) orientation of asymmetrical diimines in tris-chelate transition metal complexes. Diimine ligands have long been the workhorse of coordination chemistry, and whilst there are now good strategies to isolate materials where the inherent metal centered chirality is under almost complete control, and systematic methodologies to isolate heteroleptic complexes, the conceptually simple geometrical isomerism has not been widely investigated. In systems where the two donor atoms are significantly different in terms of the ?-donor and ?-accepting ability, the fac isomer is likely to be the thermodynamic product. For the diimine complexes with two trigonal planar nitrogen atoms there is much more subtlety to the system, and external factors such as the solvent, lattice packing and the various steric considerations play a delicate role in determining the observed and isolable product. In this article we discuss the possibilities to control the isomeric ratio in labile systems, consider the opportunities to separate inert complexes and discuss the observed differences in their spectroscopic properties. Finally we report on the ligand orientation in supramolecular systems where facial coordination leads to simple regular structures such as helicates and tetrahedra, but the ability of the ligand system to adopt a mer orientation enables self-assembled structures of considerable beauty and complexity. PMID:25600485

Dabb, Serin L; Fletcher, Nicholas C

2015-03-14

410

The iron chelator desferrioxamine attenuates postischemic ventricular dysfunction  

SciTech Connect

Recent evidence suggests that postischemic myocardial dysfunction (stunning) may be mediated by oxygen free radicals, but the mechanism by which they produce myocellular damage remains unknown. Since iron catalyzes formation of hydroxyl radicals (HO{center dot}) as well as HO{center dot}-initiated lipid peroxidation, the authors explored the potential role of this metal in the pathogenesis of myocardial stunning. Open-chest dogs undergoing a 15-min occlusion of the left anterior descending coronary artery (LAD) followed by 4 h of reperfusion (REP) received the iron chelator desferrioxamine intravenously or normal saline. Regional myocardial function was assessed by measuring systolic wall thickening with an epicardial Doppler probe. The two groups exhibited comparable systolic thickening under base-line conditions and similar degrees of dyskinesis during ischemia. After REP, however, recovery of contractile function as considerably greater in desferrioxamine-treated compared with control dogs. These differences could not be ascribed to hemodynamic factors. The results suggest that iron-catalyzed reactions (possibly HO{center dot} generation) play a significant role in myocardial stunning after a brief episode of reversible regional ischemia.

Bolli, R.; Patel, B.S.; Zhu, Weixi; O'Neill, P.G.; Hartley, C.J.; Charlat, M.L.; Roberts, R. (Baylor College of Medicine, Houston, TX (US))

1987-12-01

411

Provocative chelation with DMSA and EDTA: evidence for differential access to lead storage sites  

Microsoft Academic Search

OBJECTIVES--To validate a provocative chelation test with 2,3-dimercaptosuccinic acid (DMSA) by direct comparison with the standard ethylene diamine tetraacetic acid (EDTA) test in the same subjects; and to compare and contrast the predictors of lead excretion after DMSA with those after EDTA. A metal chelating agent given orally, DMSA may mobilise and enhance the excretion of lead from the storage

B K Lee; B S Schwartz; W Stewart; K D Ahn

1995-01-01

412

Rapid anaerobic benzene oxidation with a variety of chelated Fe(III) forms  

USGS Publications Warehouse

Fe(III) chelated to such compounds as EDTA, N-methyliminodiacetie acid, ethanol diglycine, humic acids, and phosphates stimulated benzene oxidation coupled to Fe(III) reduction in anaerobic sediments from a petroleum- contaminated aquifer as effectively as or more effectively than nitrilotriacetic acid did in a previously demonstrated stimulation experiment. These results indicate that many forms of chelated Fe(III) might be applicable to aquifer remediation.

Lovley, D.R.; Woodward, J.C.; Chapelle, F.H.

1996-01-01

413

Adsorption characteristics of metal complexes by chelated copolymers with amino group  

Microsoft Academic Search

Pentaethylenehexamine, a strong-field ligand, was grafted onto copolymer to obtain chelating copolymers via suspension polymerization. The characterization of the chelating copolymers is obtained by using Fourier transform IR spectroscopy (FTIR), elemental analysis (EA), and scanning electron microscopy (SEM), respectively. The N–H group absorption bands at 1560 and 3370–3412cm?1 are shifted to higher frequency when the cupric ion or Cu(II)–EDTA complex

Cheng-Chien Wang; Chun-Chih Wang

2006-01-01

414

Desferrithiocin analogue iron chelators: iron clearing efficiency, tissue distribution, and renal toxicity  

Microsoft Academic Search

The current solution to iron-mediated damage in transfusional iron overload disorders is decorporation of excess unmanaged\\u000a metal, chelation therapy. The clinical development of the tridentate chelator deferitrin (1, Table 1) was halted due to nephrotoxicity. It was then shown by replacing the 4?-(HO) of 1 with a 3,6,9-trioxadecyloxy group, the nephrotoxicity could be ameliorated. Further structure–activity relationship studies\\u000a have established that

Raymond J. Bergeron; Jan Wiegand; Neelam Bharti; James S. McManis; Shailendra Singh

2011-01-01

415

Soft Chelating Irrigation Protocol Optimizes Bonding Quality of Resilon\\/Epiphany Root Fillings  

Microsoft Academic Search

This study was designed to test the impact of either a strong (MTAD) or a soft (1-hydroxyethylidene-1, 1-bisphosphonate [HEPB]) chelating solution on the bond strength of Resilon\\/Epiphany root fillings. Both 17% EDTA and the omission of a chelator in the irrigation protocol were used as reference treatments. Forty extracted human upper lateral incisors were prepared using different irrigation protocols (n

Gustavo De-Deus; Fátima Namen; João Galan; Matthias Zehnder

2008-01-01

416

Predominant Intermediate-Spin Ferrous Iron in Lowermost Mantle Post-Perovskite and Perovskite  

NASA Astrophysics Data System (ADS)

Silicate post-perovskite and perovskite are believed to be the dominant minerals of the lowermost mantle and the lower mantle, respectively, and their properties, which can be strongly influenced by the electronic state of iron in these phases, affect our understanding of the nature of the deep Earth. To date, in these minerals the electronic spin state of iron remains unknown under lowermost-mantle pressure-temperature conditions, although recent studies have showed an electronic spin crossover from high-spin to low-spin in ferropericlase over an extended pressure-temperature range of the lower mantle (i.e., Lin et al., Science, 2007) and from high-spin to intermediate-spin in silicate perovskite near the top of the lower mantle (McCammon et al., Nature Geoscience, 2008). Here we report the spin and valence states of iron in post-perovskite and perovskite at pressure-temperature conditions relevant to the lowermost mantle using in situ X-ray emission, X-ray diffraction, and synchrotron Mossbauer spectroscopies in a laser-heated diamond cell. Perovskite and post-perovskite display extremely high quadrupole splitting (QS) of approximately 4 mm/s and relatively high center shift in the synchrotron Mossbauer spectra at 110 GPa and 134 GPa, respectively. Our results show that Fe2+ exists predominantly in the intermediate-spin state with a total spin number of one in both phases (Lin et al., Nature Geoscience, 2008). Together with recent results on the effects of the spin transition in the lower-mantle ferropericlase (see a recent review by Lin and Tsuchiya, PEPI, 2008), here we will address how the electronic spin states in lower-mantle phases and their associated effects affect our understanding on the composition, geophysics, and dynamics of the lower mantle.. References: 1. Lin, J. F., H. C. Watson, G. Vanko, E. E. Alp, V. B. Prakapenka, P. Dera, V. V. Struzhkin, A. Kubo, J. Zhao, C. McCammon, W. J. Evans, Intermediate-spin ferrous iron in lowermost mantle post-perovskite and perovskite, Nature Geosciences, 2008. 2. Lin, J. F., and T. Tsuchiya, Spin transition of iron in the Earth's lower mantle, Phys. Earth Planet. Inter., doi:10.1016/j.pepi.2008.01.005, 2008. 3. Lin, J. F., G. Vanko, S. D. Jacobsen, V. Iota-Herbei, V. V. Struzhkin, V. B. Prakapenka, A. Kuznetsov, and C.-S.Yoo, Spin transition zone in Earth's lower mantle, Science, 317, 1740-1743, 2007.

Lin, J.; Watson, H. C.; Vanko, G.; Alp, E. E.; Prakapenka, V.; Dera, P.; Struzhkin, V. V.; Kubo, A.; Zhao, J.; McCammon, C.; Evans, W. J.

2008-12-01

417

Fine and ultrafine emission dynamics from a ferrous foundry cupola furnace.  

PubMed

Aerosol size distributions from ferrous foundry cupola furnaces vary depending on semicontinuous process dynamics, time along the tap-to-tap cycle, dilution ratio, and the physical and chemical nature of the charge and fuel. All of these factors result in a highly time-dependent emission of particulate matter (PM) 2.5 pm or less in aerodynamic diameter (PM2.5)--even on a mass concentration basis. Control measures are frequently taken on the basis of low-reliability parameters such as emission factors and loosely established mass ratios of PM2.5 to PM 10 microm or less in aerodynamic diameter (PM1.0). The new environmental requirements could entail unexpected and undesired drawbacks and uncertainties in the meaning and effectiveness of process improvement measures. The development of process-integrated and flue-gas cleaning measures for reduction of particle emissions requires a better knowledge of generation mechanisms during melting. Available aerosol analyzers expand the range of control issues to be tackled and contribute to greatly reduce the uncertainty of engineering decisions on trace pollutant control. This approach combines real-time size distribution monitoring and cascade impactors as preseparators for chemical or morphological analysis. The results allow for establishing a design rationale and performance requirement for control devices. A number size distribution below 10 microm in aerodynamic equivalent diameter was chosen as the main indicator of charge influence and filter performance. Size distribution is trimodal, with a coarse mode more than 12 microm that contributes up to 30% of the total mass. A temporal series for these data leads to identification of the most relevant size ranges for a specific furnace (e.g., the most penetrating size range). In this cupola, this size range is between 0.32 and 0.77 microm of aerodynamic equivalent diameter and defines the pollution control strategy for metals concentrating within this size range. Scrap quality effect is best monitored at less than 0.2 microm in aerodynamic equivalent diameter and has been confirmed as strongly dependent on the physical state of the charge. PMID:20480855

Meléndez, Antton; García, Estibaliz; Carnicer, Pedro; Pena, Egoitz; Larrión, Miren; Legarreta, Juan Andres; Gutiérrez-Cañas, Cristina

2010-05-01

418

Oxygen reduction and lipid peroxidation by iron chelates with special reference to ferric nitrilotriacetate.  

PubMed

A certain iron chelate, ferric nitrilotriacetate (Fe3+-NTA) is nephrotoxic and also carcinogenic to the kidney in mice and rats, a distinguishing feature not shared by other iron chelates tested so far. Iron-promoted lipid peroxidation is thought to be responsible for the initial events. We examined its ability to initiate lipid peroxidation in vitro in comparison with that of other ferric chelates. Chelation of Fe2+ by nitrilotriacetate (NTA) enhanced the autoxidation of Fe2+. In the presence of Fe2+-NTA, lipid peroxidation occurred as measured by the formation of conjugated diene in detergent-dispersed linoleate micelles, and by the formation of thiobarbituric acid-reactive substances in the liposomes of rat liver microsomal lipids. Addition of ascorbic acid to Fe3+-NTA solution promoted dose-dependent consumption of dissolved oxygen, which indicates temporary reduction of iron. On reduction, Fe3+-NTA initiated lipid peroxidation both in the linoleate micelles and in the liposomes. Fe3+-NTA also initiated NADPH-dependent lipid peroxidation in rat liver microsomes. Although other chelators used (deferoxamine, EDTA, diethylenetriaminepentaacetic acid, ADP) enhanced autoxidation, reduction by ascorbic acid, or in vitro lipid peroxidation of linoleate micelles or liposomal lipids, NTA was the sole chelator that enhanced all the reactions. PMID:2500058

Hamazaki, S; Okada, S; Li, J L; Toyokuni, S; Midorikawa, O

1989-07-01

419

Effect of chelators on copper metabolism and copper pools in mouse hepatocytes  

SciTech Connect

Disorders of copper storage are usually treated by chelation therapy. It is generally thought that the chelators act by mobilizing copper from the liver, hence allowing excretion in the urine. This paper has examined the effect of chelators on copper uptake and storage in mouse hepatocytes. Penicillamine, a clinically important chelator, does not block the uptake of copper or remove copper from hepatocytes. Two other copper chelators, sar and diamsar, which form very stable and kinetically inert Cu2+ complexes by encapsulating the metal ion in an organic cage, were shown to block copper accumulation by the cells and to remove up to 80% of cell-associated copper. They also removed most (approximately 80%) of the /sup 64/Cu accumulated by the cells in 30 min, but released only a small percentage (less than 20%) of that accumulated over 18 h. The results show that copper in the hepatocyte can be divided into at least two pools, an easily accessible one, and another, not removable even after long-term incubation with any of the chelators. Most of the copper normally found in the cell appeared to be associated with the former pool.

McArdle, H.J.; Gross, S.M.; Creaser, I.; Sargeson, A.M.; Danks, D.M.

1989-04-01

420

Wavelength conversion film with glass coated Eu chelate for enhanced silicon-photovoltaic cell performance  

NASA Astrophysics Data System (ADS)

In order to improve the conversion efficiency of a silicon-photovoltaic (PV) module, we investigated the combination with a wavelength conversion film (WCF), which consists of Eu chelate particles encapsulated by the sol-gel derived silica glass. The photoluminescence (PL) excitation spectrum of Eu chelate shows that the violet light below 400 nm is effectively converted to the red emission at 613 nm. Since the PV cell has higher sensitivity at the red wavelength region compared to the violet region, Eu chelate is one of the suitable material for a WCF. The diameter of fabricated sol-gel encapsulated Eu chelate was larger than the wavelength of irradiated sunlight, therefore, the transmittance of a WCF decreased with increasing the concentration of Eu chelate. The short circuit current ( JSC) was increased by inserting the the WCF on the front side of Si-PV cell compared to the reference module (glass/ethylene vinyl acetate/WCF without Eu chelate/Si-PV cell/EVA/back-film), and the maximum increase of ? JSC was 1.03 mA/cm 2 compared to the reference module. However, the maximum ? JSC of fabricated module was almost same as the conventional Si-PV cell due to the refractive index mismatch of each layers.

Fukuda, Takeshi; Kato, Sayaka; Kin, Eimo; Okaniwa, Kaoru; Morikawa, Hiroaki; Honda, Zentaro; Kamata, Norihiko

2009-11-01

421

The antibody-linked chelating polymers for nuclear therapy and diagnostics  

SciTech Connect

This review deals with the problem of protein modification with chelating polymers. The main purpose of this approach is the preparation of monoclonal antibodies labeled with heavy metal isotopes ({alpha}-, {beta}-, and {delta}-emitting metals and metals used for NMR-tomography). Traditional binding of metals with proteins via chelating agents directly coupled to protein molecule does not allow binding a high number of metal atoms per single protein molecule and can also alter protein specific properties. At the same time, metal-to-protein binding via intermediate chelating polymer makes possible the binding of several dozen metal atoms per single protein without affecting its specific properties. Moreover, the variations in polymer properties and molecular weight allow controlled modified antibody biodistribution and clearance rate. Modified antibodies can be used successfully for nuclear and NMR diagnostics and for nuclear therapy. The following problems are discussed: the chemistry of the coupling of chelating groups to polymer backbone; the binding of chelating polymers to proteins, including monoclonal antibodies; the ability of chelating polymer-to-protein conjugates to bind heavy metals; the influence of the modification on protein conformation and specific properties; the behavior of metal-containing conjugates in vivo; the practical use of conjugates obtained for radioimmunoimaging, radioimmunotherapy, NMR-tomography, and in vitro immunoassays. Future prospects of the approach are also discussed.101 references.

Torchilin, V.P.; Klibanov, A.L. (USSR Cardiology Research Center, Moscow (USSR))

1991-01-01

422

Mathematical modeling of the effects of aerobic and anaerobic chelate bioegradation on actinide speciation.  

SciTech Connect

Biodegradation of natural and anthropogenic chelating agents directly and indirectly affects the speciation, and, hence, the mobility of actinides in subsurface environments. We combined mathematical modeling with laboratory experimentation to investigate the effects of aerobic and anaerobic chelate biodegradation on actinide [Np(IV/V), Pu(IV)] speciation. Under aerobic conditions, nitrilotriacetic acid (NTA) biodegradation rates were strongly influenced by the actinide concentration. Actinide-chelate complexation reduced the relative abundance of available growth substrate in solution and actinide species present or released during chelate degradation were toxic to the organisms. Aerobic bio-utilization of the chelates as electron-donor substrates directly affected actinide speciation by releasing the radionuclides from complexed form into solution, where their fate was controlled by inorganic ligands in the system. Actinide speciation was also indirectly affected by pH changes caused by organic biodegradation. The two concurrent processes of organic biodegradation and actinide aqueous chemistry were accurately linked and described using CCBATCH, a computer model developed at Northwestern University to investigate the dynamics of coupled biological and chemical reactions in mixed waste subsurface environments. CCBATCH was then used to simulate the fate of Np during anaerobic citrate biodegradation. The modeling studies suggested that, under some conditions, chelate degradation can increase Np(IV) solubility due to carbonate complexation in closed aqueous systems.

Banaszak, J.E.; VanBriesen, J.; Rittmann, B.E.; Reed, D.T.

1998-03-19

423

Nitrosyl hydride (HNO) as an O2 analogue: long-lived HNO-adducts of ferrous globins†  

PubMed Central

Nitrosyl hydride, HNO or nitroxyl, is the one-electron reduced and protonated form of nitric oxide. HNO is isoelectronic to singlet O2, and we have previously reported that deoxy myoglobin traps free HNO to form a stable adduct. In this report, we demonstrate that oxygen-binding hemoglobins from human, soy and clam also trap HNO to form adducts which are stable over a period of weeks. The same species can be formed in higher yield by careful reduction of the ferrous nitrosyl adducts of the proteins. Like the analogous O2-FeII adducts, the HNO adducts are diamagnetic, but with a characteristic HNO resonance in 1H NMR ca. 15 ppm that splits into doublets for H15NO adducts. The 1H and 15N NMR resonances, obtained by HSQC experiments, are shown to differentiate subunits and isoforms of proteins within mixtures. An apparent difference in reduction rates of the NO-adducts of the two subunits of human hemoglobin allows assignment of two distinct nitrosyl hydride peaks by a combination of UVvis, NMR and EPR analysis. The two peaks of HNO-hHb have a persistent 3:1 ratio during trapping reactions, demonstrating a kinetic difference between HNO binding at the two subunits. These results show NMR characterization of ferrous HNO adducts as a unique tool sensitive to structural changes within the oxygen-binding cavity, which may be of use in defining modes of oxygen binding in other heme proteins and enzymes. PMID:19368336

Kumar, Murugaeson R.; Pervitsky, Dmitry; Chen, Lan; Poulos, Thomas; Kundu, Suman; Hargrove, Mark S.; Rivera, Eladio J.; Diaz, Agustin; Colón, Jorge L.; Farmer, Patrick J.

2009-01-01

424

Study of the dose response of the system ferrous ammonium sulfate-sucrose-xylenol orange in acid aqueous solution  

NASA Astrophysics Data System (ADS)

An aqueous solution of ammonium ferrous sulfate-sucrose-xylenol orange in sulfuric acid (FSX) is proposed as a dosimetric system for the processes of gamma irradiation in a range between 0.3 and 6 Gy. This system is based on the indirect oxidation of ferrous ion by an organic compound (sucrose) to ferric ion and on the formation of a color complex of Fe3+ in an acidic medium with xylenol orange (a dye). After gamma radiation, an observable change occurs in the color of the system. Irradiation was executed at three different temperatures (13 °C, 22 °C, and 40 °C). A spectrometric readout method at 585 nm was employed to evaluate the system's dose response. In all of the cases analyzed, the responses had a linear behavior, and a slight effect of irradiation temperature was observed. Post-irradiation response was also evaluated and showed the stability of the solutions 24 h after the irradiation. The results obtained suggest that FSX might be used as a dosimeter for low doses of gamma irradiation because it provides a stable signal, good reproducibility, and an accessible technique for analysis.

Juarez-Calderon, J. M.; Negron-Mendoza, A.; Ramos-Bernal, S.

2014-11-01

425

Structure and catalytic activities of ferrous centers confined on the interface between carbon nanotubes and humic acid.  

PubMed

Preparation of heterogeneous catalysts with active ferrous centers is of great significance for industrial and environmental catalytic processes. Nanostructured carbon materials (NCM), which possess free-flowing ? electrons, can coordinate with transition metals, provide a confinement environment for catalysis, and act as potential supports or ligands to construct analogous complexes. However, designing such catalysts using NCM is still seldom studied to date. Herein, we synthesized a sandwich structured ternary complex via the coordination of Fe-loaded humic acid (HA) with C[double bond, length as m-dash]C bonds in the aromatic rings of carbon nanotubes (CNTs), in which the O/N-Fe-C interface configuration provides the confinement environment for the ferrous sites. The experimental and theoretical results revealed octahedrally/tetrahedrally coordinated geometry at Fe centers, and the strong hybridization between CNT C ?* and Fe 3d orbitals induces discretization of the atomic charges on aromatic rings of CNTs, which facilitates O2 adsorption and electron transfer from carbon to O2, which enhances O2 activation. The O2 activation by the novel HA/Fe-CNT complex can be applied in the oxidative degradation of phenol red (PR) and bisphenol A (BPA) in aqueous media. PMID:25580558

Wang, Bing; Zhou, Xiaoyan; Wang, Dongqi; Yin, Jun-Jie; Chen, Hanqing; Gao, Xingfa; Zhang, Jing; Ibrahim, Kurash; Chai, Zhifang; Feng, Weiyue; Zhao, Yuliang

2015-01-28

426

Nitrate-dependent anaerobic ferrous oxidation (NAFO) by denitrifying bacteria: a perspective autotrophic nitrogen pollution control technology.  

PubMed

The nitrate-dependent anaerobic ferrous oxidation (NAFO) is an important discovery in the fields of microbiology and geology, which is a valuable biological reaction since it can convert nitrate into nitrogen gas, removing nitrogen from wastewater. The research on NAFO can promote the development of novel autotrophic biotechnologies for nitrogen pollution control and get a deep insight into the biogeochemical cycles. In this work, batch experiments were conducted with denitrifying bacteria as biocatalyst to investigate the performance of nitrogen removal by NAFO. The results showed that the denitrifying bacteria were capable of chemolithotrophic denitrification with ferrous salt as electron donor, namely NAFO. And the maximum nitrate conversion rates (qmax) reached 57.89 mg (g VSS d)?1, which was the rate-limiting step in NAFO. Fe/N ratio, temperature and initial pH had significant influences on nitrogen removal by NAFO process, and their optimal values were 2.0 °C, 30.15 °C and 8.0 °C, respectively. PMID:25461924

Zhang, Meng; Zheng, Ping; Wang, Ru; Li, Wei; Lu, Huifeng; Zhang, Jiqiang

2014-12-01

427

Evaluation of efficacy and safety of iron polymaltose complex and folic acid (Mumfer) vs iron formulation (ferrous fumarate) in female patients with anaemia.  

PubMed

Treatment of iron deficiency anaemia with conventional oral preparations is handicapped by unpredictable haematological response in addition to potential for irritating gastrointestinal adverse events. Iron polymaltose complex (IPC), a novel oral iron formulation with better absorbability, predictable haematinic response and less side effects was compared with oral ferrous fumarate in 100 female patients with documented iron deficiency anaemia. Clinical parameters (pallor, weakness) as well as biochemical parameters (Hb, serum iron, total iron binding capacity) show favourable changes with IPC; the physician and patient assessment also favour IPC over ferrous fumarate. PMID:11478761

Reddy, P S; Adsul, B B; Gandewar, K; Korde, K M; Desai, A

2001-03-01

428

Comparative effects of chelating agents on distribution, excretion, and renal toxicity of inorganic mercury in rats  

SciTech Connect

The effects of three chelating agents, sodium N-benzyl-D-glucamine dithiocarbamate(NBG-DTC), 2,3-dimercaptopropanol(BAL), and D-penicillamine(D-PEN), on the distribution, excretion, and renal toxicity of inorganic mercury were compared in rats exposed to HgCl2. Rats were injected i.p. with 203HgCl2 (300 micrograms of Hg and 2 microCi of 203Hg/kg) and 30 min or 24 h later they were injected with a chelating agent (a quarter of an LD50). The injection of the chelating agents significantly enhanced the biliary and urinary excretions of mercury. BAL was the most effective for removal of mercury from the body at 30 min after mercury treatment. The extent of enhancing effect of the chelating agents for removal of mercury at 24 h after mercury was in the order NBG-DTC = BAL greater than D-PEN. The injection of BAL at 24 h after mercury treatment caused the redistribution of mercury to the heart and lung. NBG-DTC did not result in the redistribution of mercury to the heart, lung, and brain. Urinary excretion of protein and AST significantly increased 24-48 h after mercury treatment and decreased to the control values 72 h after mercury. The injection of the chelating agents at 30 min after mercury treatment significantly decreased the urinary excretion of protein and AST. In rats pretreated with mercury 24 h earlier, the chelating agents significantly decreased the urinary protein at 48 h after mercury treatment, but did not decrease the urinary AST. The results of this study indicate that the chelating agents are effective in removing mercury from the body, resulting in the protective effect against the mercury-induced renal damage.

Kojima, S.; Shimada, H.; Kiyozumi, M. (Kumamoto Univ. (Japan))

1989-06-01

429

Chelation: A Fundamental Mechanism of Action of AGE Inhibitors, AGE Breakers, and Other Inhibitors of Diabetes Complications  

PubMed Central

This article outlines evidence that advanced glycation end product (AGE) inhibitors and breakers act primarily as chelators, inhibiting metal-catalyzed oxidation reactions that catalyze AGE formation. We then present evidence that chelation is the most likely mechanism by which ACE inhibitors, angiotensin receptor blockers, and aldose reductase inhibitors inhibit AGE formation in diabetes. Finally, we note several recent studies demonstrating therapeutic benefits of chelators for diabetic cardiovascular and renal disease. We conclude that chronic, low-dose chelation therapy deserves serious consideration as a clinical tool for prevention and treatment of diabetes complications. PMID:22354928

Nagai, Ryoji; Murray, David B.; Metz, Thomas O.; Baynes, John W.

2012-01-01

430

Comparative study on fluorescence enhancement and quenching of europium and terbium chelate anions in cationic micelles  

NASA Astrophysics Data System (ADS)

Fluorescence enhancement and quenching of water soluble chelates of terbium (Tb 3+) with Tiron, salicylic acid (SA), 4-sulfonyl salicylic acid (SSA) and acetylacetone (AA) and sparingly soluble chelates of europium (Eu 3+) with ?-diketones were comparatively examined in the presence of cetyltrimethyl ammonium bromide (CTMAB) and cetylpyridinium chloride (CPC). By the composition of the complexes, surface tension measurements and spectral analysis, the binding mode of chelate anions to the micellar surface of cationic surfactants was discussed in terms of ion-exchange model. Quenching effect of CPC on the fluorescence of association complexes seems to arise from the charge transfer from a fluorescent ligand to pyridinium cation. In the case of the chelates of Eu 3+ with ?-diketones, however, pyridinium ion is only capable of overlapping the aromatic ring of ?-diketones to less extent since the poorly soluble charged chelates have a weak affinity for the highly polar surface of pyridinium cationic micelles. Efficient charge transfer between the excited aromatic ?-diketone and pyridinium cation fails to be established. CPC also shows enhanced effect on fluorescence like CTMAB.

Du, Xinzhen; Hou, Jinguo; Deng, Hualin; Gao, Jinzhang; Kang, Jingwan

2003-01-01

431

Comparative study on fluorescence enhancement and quenching of europium and terbium chelate anions in cationic micelles.  

PubMed

Fluorescence enhancement and quenching of water soluble chelates of terbium (Tb3+) with Tiron, salicylic acid (SA), 4-sulfonyl salicylic acid (SSA) and acetylacetone (AA) and sparingly soluble chelates of europium (Eu3+) with beta-diketones were comparatively examined in the presence of cetyltrimethyl ammonium bromide (CTMAB) and cetylpyridinium chloride (CPC). By the composition of the complexes, surface tension measurements and spectral analysis, the binding mode of chelate anions to the micellar surface of cationic surfactants was discussed in terms of ion-exchange model. Quenching effect of CPC on the fluorescence of association complexes seems to arise from the charge transfer from a fluorescent ligand to pyridinium cation. In the case of the chelates of Eu3+ with beta-diketones, however, pyridinium ion is only capable of overlapping the aromatic ring of beta-diketones to less extent since the poorly soluble charged chelates have a weak affinity for the highly polar surface of pyridinium cationic micelles. Efficient charge transfer between the excited aromatic beta-diketone and pyridinium cation fails to be established. CPC also shows enhanced effect on fluorescence like CTMAB. PMID:12685900

Du, Xinzhen; Hou, Jinguo; Deng, Hualin; Gao, Jinzhang; Kang, Jingwan

2003-01-15

432

Assessment of iron chelates efficiency for photo-Fenton at neutral pH.  

PubMed

In this study, homogeneous photo-Fenton like at neutral pH was applied to remove sulfamethoxazole from water. The process was performed using different chelating agents in order to solubilize iron in a neutral water solution. The chelating agents tested were: ethylenediaminetetraacetic acid (EDTA); nitrilotriacetic acid (NTA); oxalic acid (OA) and tartaric acid (TA). The iron leaching was monitored over reaction time to evaluate the chelates stability and their resistance to HO· and UV-A radiation. Chelates of EDTA and NTA presented more stability than OA and TA, which also confirmed their higher efficiency. Total Organic Carbon (TOC) analyses were also performed to evaluate the contribution in terms of solution contamination related to the use of chelating agents. The better properties of biodegradability in respect of EDTA combined with better efficiency in terms of microcontaminant removal and the smallest TOC contribution indicate that NTA could represent a useful option to perform photo-Fenton processes at neutral pH. PMID:24930010

De Luca, Antonella; Dantas, Renato F; Esplugas, Santiago

2014-09-15

433

Reversible adsorption of catalase onto Fe(3+) chelated poly(AAm-GMA)-IDA cryogels.  

PubMed

In this presented study, poly(acrylamide-glycidyl methacrylate) [poly(AAm-GMA)] cryogels were synthesized by cryopolymerization technique at sub-zero temperature. Prepared cryogels were then functionalized with iminodiacetic acid (IDA) and chelated with Fe(3+) ions in order produce the metal chelate affinity matrix. Synthesized cryogels were characterized with FTIR, ESEM and EDX analysis, and it was found that the cryogel had sponge like structure with interconnected pores and their pore diameter was about 200?m. Fe(3+) chelated poly(AAm-GMA)-IDA cryogels were used for the adsorption of catalase and optimum adsorption conditions were determined by varying the medium pH, initial catalase concentration, temperature and ionic strength. Maximum catalase adsorption onto Fe(3+) chelated poly(AAm-GMA)-IDA cryogel was found to be 12.99mg/g cryogel at 25°C, by using pH5.0 acetate buffer. Adsorbed catalase was removed from the cryogel by using 1.0M of NaCl solution and desorption yield was found to be 96%. Additionally, reusability profile of the Fe(3+) chelated poly(AAm-GMA)-IDA cryogel was also investigated and it was found that, adsorption capacity of the cryogels didn't decrease significantly at the end of the 40 reuses. Catalase activity studies were also tested and it was demonstrated that desorbed catalase retained 70% of its initial activity. PMID:25746283

Akta? Uygun, Deniz; Uygun, Murat; Akgöl, Sinan; Denizli, Adil

2015-05-01

434

Arsenic induced oxidative stress and the role of antioxidant supplementation during chelation: a review.  

PubMed

Arsenic is a naturally occurring metalloid, ubiquitously present in the environment in both organic and inorganic forms. Arsenic contamination of groundwater in the West Bengal basin in India is unfolding as one of the worst natural geoenvironmental disaster to date. Chronic exposure of humans to high concentration of arsenic in drinking water is associated with skin lesions, peripheral vascular disease, hypertension, Blackfoot disease and high risk of cancer The underlying mechanism of toxicity includes the interaction with the sulphydryl groups and the generation of reactive oxygen species leading to oxidative stress. Chelation therapy with chelating agents like British Anti Lewisite (BAL), sodium 2,3-dimercaptopropane 1-sulfonate (DMPS), meso 2,3 dimercaptosuccinic acid (DMSA) etc., is considered to be the best known treatment against arsenic poisoning. The treatment with these chelating agents however is compromised with certain serious drawbacks/side effects. The studies show that supplementation of antioxidants along with a chelating agent prove to be a better treatment regimen. This review attempts to provide the readers with a comprehensive account of recent developments in the research on arsenic poisoning particularly the role of oxidative stress/free radicals in the toxic manifestation, an update about the recent strategies for the treatment with chelating agents and a possible beneficial role of antioxidants supplementation to achieve the optimum effects. PMID:17929749

Flora, S J S; Bhadauria, Smrati; Kannan, G M; Singh, Nutan

2007-04-01

435

Pharmacological properties of orally available, amphipathic polyaminocarboxylic acid chelators for actinide decorporation.  

PubMed

Commonly used water-soluble polyaminocarboxylic acid (PACA) chelators, such as EDTA and DTPA, require intravenous or subcutaneous administration due to their poor bioavailability. The bioavailability of PACAs can be improved by the addition of differing lengths of alkyl side chains that alter amphipathic properties. Orally administered amphipathic triethylenetetramine pentaacetic acid (TT) compounds are efficacious for decorporation of plutonium and americium. The synthesis, efficacy, binding affinities, and some initial pharmacokinetics properties of amphipathic TT chelators are reviewed. C-labeled C12TT and C22TT chelators are reasonably well absorbed from the intestine and have a substantial biliary/fecal excretion pathway, unlike DTPA, which is mostly excreted in the urine. Whole body retention times are increased as a function of increasing lipophilicity. Neutron-induced autoradiography studies demonstrate that the oral administration of the chelators can substantially inhibit the redistribution of Pu in skeletal tissues. In summary, amphipathic TT-based chelators have favorable bioavailability, have a significant biliary excretion pathway, have demonstrated efficacy for americium and plutonium, and are thus good candidates for further development. Furthermore, some of the pharmacological properties can be manipulated by changing the lengths of the alkyl side chains and this may have some advantage for decorporation of certain metals and radionuclides. PMID:20699705

Miller, Scott C; Wang, Xuli; Bowman, Beth M

2010-09-01

436

Chelation and intercalation: complementary properties in a compound for the treatment of Alzheimer's disease.  

PubMed

Selective application of metal chelators to homogenates of human Alzheimer's disease (AD) brain has led us to propose that the architecture of aggregated beta-amyloid peptide, whether in the form of plaques or soluble oligomers, is determined at least in part by high-affinity binding of transition metals, especially copper and zinc. Of the two metals, copper is implicated in reactive oxygen species generating reactions, while zinc appears to be associated with conformational and antioxidant activity. We tested the copper chelators trientine, penicillamine, and bathophenanthroline for their ability to mobilize brain Abeta as measured against our benchmark compound bathocuproine (BC). All of these agents were effective in solubilizing brain Abeta, although BC was the most consistent across the range of AD brain tissue samples tested. Similarly, all of the copper chelators depleted copper in the high-speed supernatants. BC alone had no significant effect upon zinc levels in the soluble fraction. BC extraction of brain tissue from C100 transgenic mice (which express human Abeta but do not develop amyloid) revealed SDS-resistant dimers as Abeta was mobilized from the sedimentable to the soluble fraction. NMR analysis showed that, in addition to its copper chelating properties, BC interacts with Abeta to form a complex independent of the presence of copper. Such hybrid copper chelating and "chain breaking" properties may form the basis of a rational design for a therapy for Alzheimer's disease. PMID:10940226

Cherny, R A; Barnham, K J; Lynch, T; Volitakis, I; Li, Q X; McLean, C A; Multhaup, G; Beyreuther, K; Tanzi, R E; Masters, C L; Bush, A I

2000-06-01

437

Iron Chelators with Topoisomerase-Inhibitory Activity and Their Anticancer Applications  

PubMed Central

Abstract Significance: Iron and topoisomerases are abundant and essential cellular components. Iron is required for several key processes such as DNA synthesis, mitochondrial electron transport, synthesis of heme, and as a co-factor for many redox enzymes. Topoisomerases serve as critical enzymes that resolve topological problems during DNA synthesis, transcription, and repair. Neoplastic cells have higher uptake and utilization of iron, as well as elevated levels of topoisomerase family members. Separately, the chelation of iron and the cytotoxic inhibition of topoisomerase have yielded potent anticancer agents. Recent Advances: The chemotherapeutic drugs doxorubicin and dexrazoxane both chelate iron and target topoisomerase 2 alpha (top2?). Newer chelators such as di-2-pyridylketone-4,4,-dimethyl-3-thiosemicarbazone and thiosemicarbazone -24 have recently been identified as top2? inhibitors. The growing list of agents that appear to chelate iron and inhibit topoisomerases prompts the question of whether and how these two distinct mechanisms might interplay for a cytotoxic chemotherapeutic outcome. Critical Issues: While iron chelation and topoisomerase inhibition each represent mechanistically advantageous anticancer therapeutic strategies, dual targeting agents present an attractive multi-modal opportunity for enhanced anticancer tumor killing and overcoming drug resistance. The commonalities and caveats of dual inhibition are presented in this review. Future Directions: Gaps in knowledge, relevant biomarkers, and strategies for future in vivo studies with dual inhibitors are discussed. Antioxid. Redox Signal. 00, 000–000. PMID:22900902

2013-01-01

438

Identifying Chelators for Metalloprotein Inhibitors Using a Fragment-Based Approach  

PubMed Central

Fragment-based lead design (FBLD) has been used to identify new metal-binding groups for metalloenzyme inhibitors. When screened at 1 mM, a chelator fragment library (CFL-1.1) of 96 compounds produced hit rates ranging from 29–43% for five matrix metalloproteases (MMPs), 24% for anthrax lethal factor (LF), 49% for 5-lipoxygenase (5-LO), and 60% for tyrosinase (TY). The ligand efficiencies (LE) of the fragment hits are excellent, in the range of 0.4–0.8 kcal/mol. The MMP enzymes all generally elicit the same chelators as hits from CFL-1.1; however, the chelator fragments that inhibit structurally unrelated metalloenzymes (LF, 5-LO, TY) vary considerably. To develop more advanced hits, one hit from CFL-1.1, 8-hydroxyquinoline, was elaborated at four different positions around the ring system to generate new fragments. 8-Hydroxyquinoline fragments substituted at either the 5- or 7-positions gave potent hits against MMP-2, with IC50 values in the low micromolar range. The 8-hydroxyquinoline represents a promising, new chelator scaffold for the development of MMP inhibitors that was discovered by use of a metalloprotein-focused chelator fragment library. PMID:21189019

Jacobsen, Jennifer A.; Fullagar, Jessica; Miller, Melissa T.; Cohen, Seth M.

2011-01-01

439

Effects of extraction solvents on concentration and antioxidant activity of black and black mate tea polyphenols determined by ferrous tartrate and Folin–Ciocalteu methods  

Microsoft Academic Search

Effect of the use of water and different organic solvents such as acetone, N,N-dimethylformamide (DMF), ethanol or methanol at various concentrations on the total polyphenol content and antioxidant activity was studied for the black tea and mate tea. Polyphenol contents of extracts were determined using ferrous tartrate (method # 1) and Folin–Ciocalteu (method # 2) assays. For black tea, 50%

Nihal Turkmen; Ferda Sari; Y. Sedat Velioglu

2006-01-01

440

A Density Functional Theory Study of Conformers in the Ferrous CO Complex of Horseradish Peroxidase with Distinct Fe-C-O Configurations  

E-print Network

A Density Functional Theory Study of Conformers in the Ferrous CO Complex of Horseradish Peroxidase, 2002 The reactive site structure and CO IR spectral signature of horseradish peroxidase complexed to horseradish peroxidase type C (HRPC). HRPC is an enzyme that catalyzes the oxidation of a variety of organic

Sharp, Kim

441

2008 Macmillan Publishers Limited. All rights reserved. 2008 Macmillan Publishers Limited. All rights reserved. Intermediate-spin ferrous iron in lowermost  

E-print Network

the core­mantle boundary is generally characterized by strong seismic discontinuities1­4 . Recent discovery rights reserved. LETTERS Intermediate-spin ferrous iron in lowermost mantle post-perovskite and perovskite are believed to be the dominant minerals of the lowermost mantle and the lower mantle

Lin, Jung-Fu "Afu"

442

TREATMENT OF A SATURATED ZONE HEXAVALENT CHROMIUM SOURCE AREA USING A FERROUS SULFATE/SODIUM DITHIONITE MIXTURE: A FIELD PILOT STUDY  

EPA Science Inventory

A field pilot study was conducted to evaluate the performance of a combined ferrous sulfate/sodium dithionite solution for in situ treatment of a saturated zone hexavalent chromium source area at a former ferrochromium alloy production facility in Charleston, S.C. The saturate...

443

Ferrous Silicate Spherules with Euhedral Fe,Ni-Metal Grains in CH Carbonaceous Chondrites: Evidence for Condensation Under Highly Oxidizing Conditions  

NASA Technical Reports Server (NTRS)

A population of ferrous silicate spherules composed of cryptocrystalline ol-px-normative material, +/-SiO2-rich glass and rounded-to-euhedral Fe,Ni-metal grains preserved a condensation signature of the precursors formed under oxidizing conditions.

Krot, A. N.; Meibom, A.; Petaev, M. I.; Keil, K.; Zolensky, M. E.; Saito, A.; Mukai, M.; Ohsumi, K.

2000-01-01

444

Effects of ferrous sulphate and non-ionic iron-polymaltose complex on markers of oxidative tissue damage in patients with inflammatory bowel disease  

Microsoft Academic Search

SUMMARY Background: Iron deficiency is a common complication of inflammatory bowel disease. Oral iron therapy may reinforce intestinal tissue injury by catalyzing produc- tion of reactive oxygen species. Aim: To compare the effects of ferrous sulphate and non- ionic iron-polymaltose complex on markers of oxidative tissue damage and clinical disease activity in patients with inflammatory bowel disease. Methods: Forty-one patients

E RICHSEN

445

Decreased Treatment Failure Rates following Duodenal Release Ferrous Glycine Sulfate in Iron Deficiency Anemia Associated with Autoimmune Gastritis and Helicobacter pylori Gastritis  

Microsoft Academic Search

Background and Objectives: Since gastric acidity and ascorbate play a critical role in the solubilization and reduction of iron for subsequent absorption, the achlorhydria associated with autoimmune and Helicobacter pylori gastritis may explain the poor response of such patients to oral iron treatment. In order to circumvent this problem, we explored the therapeutic potential of a duodenal formulation of ferrous

Chaim Hershko; Mara Ianculovich; Moshe Souroujon

2007-01-01

446

Detoxification of acid pretreated spruce hydrolysates with ferrous sulfate and hydrogen peroxide improves enzymatic hydrolysis and fermentation.  

PubMed

The aim of the present work was to investigate whether a detoxification method already in use during waste water treatment could be functional also for ethanol production based on lignocellulosic substrates. Chemical conditioning of spruce hydrolysate with hydrogen peroxide (H?O?) and ferrous sulfate (FeSO?) was shown to be an efficient strategy to remove significant amounts of inhibitory compounds and, simultaneously, to enhance the enzymatic hydrolysis and fermentability of the substrates. Without treatment, the hydrolysates were hardly fermentable with maximum ethanol concentration below 0.4 g/l. In contrast, treatment by 2.5 mM FeSO? and 150 mM H?O? yielded a maximum ethanol concentration of 8.3 g/l. PMID:24953967

Soudham, Venkata Prabhakar; Brandberg, Tomas; Mikkola, Jyri-Pekka; Larsson, Christer

2014-08-01

447

Enhancement of gaseous iodine emission by aqueous ferrous ions during the heterogeneous reaction of gaseous ozone with aqueous iodide.  

PubMed

Gaseous I2 formation from the heterogeneous reaction of gaseous ozone with aqueous iodide in the presence of aqueous ferrous ion (Fe(2+)) was investigated by electron impact ionization mass spectrometry. Emission of gaseous I2 increased as a function of the aqueous FeCl2 concentration, and the maximum I2 formation with Fe(2+) was about 10 times more than without Fe(2+). This enhancement can be explained by the OH(-) scavenging by Fe(3+) formed from Fe(2+) ozonation to produce colloidal Fe(OH)3. This mechanism was confirmed by measurements of aqueous phase products using a UV-vis spectrometer and an electrospray ionization mass spectrometer. We infer that such a pH-buffering effect may play the key role in general halogen activations. PMID:23485095

Sakamoto, Yosuke; Enami, Shinichi; Tonokura, Kenichi

2013-04-11

448

Structure and catalytic activities of ferrous centers confined on the interface between carbon nanotubes and humic acid  

NASA Astrophysics Data System (ADS)

Preparation of heterogeneous catalysts with active ferrous centers is of great significance for industrial and environmental catalytic processes. Nanostructured carbon materials (NCM), which possess free-flowing ? electrons, can coordinate with transition metals, provide a confinement environment for catalysis, and act as potential supports or ligands to construct analogous complexes. However, designing such catalysts using NCM is still seldom studied to date. Herein, we synthesized a sandwich structured ternary complex via the coordination of Fe-loaded humic acid (HA) with C&z.dbd;C bonds in the aromatic rings of carbon nanotubes (CNTs), in which the O/N-Fe-C interface configuration provides the confinement environment for the ferrous sites. The experimental and theoretical results revealed octahedrally/tetrahedrally coordinated geometry at Fe centers, and the strong hybridization between CNT C ?* and Fe 3d orbitals induces discretization of the atomic charges on aromatic rings of CNTs, which facilitates O2 adsorption and electron transfer from carbon to O2, which enhances O2 activation. The O2 activation by the novel HA/Fe-CNT complex can be applied in the oxidative degradation of phenol red (PR) and bisphenol A (BPA) in aqueous media.Preparation of heterogeneous catalysts with active ferrous centers is of great significance for industrial and environmental catalytic processes. Nanostructured carbon materials (NCM), which possess free-flowing ? electrons, can coordinate with transition metals, provide a confinement environment for catalysis, and act as potential supports or ligands to construct analogous complexes. However, designing such catalysts using NCM is still seldom studied to date. Herein, we synthesized a sandwich structured ternary complex via the coordination of Fe-loaded humic acid (HA) with C&z.dbd;C bonds in the aromatic rings of carbon nanotubes (CNTs), in which the O/N-Fe-C interface configuration provides the confinement environment for the ferrous sites. The experimental and theoretical results revealed octahedrally/tetrahedrally coordinated geometry at Fe centers, and the strong hybridization between CNT C ?* and Fe 3d orbitals induces discretization of the atomic charges on aromatic rings of CNTs, which facilitates O2 adsorption and electron transfer from carbon to O2, which enhances O2 activation. The O2 activation by the novel HA/Fe-CNT complex can be applied in the oxidative degradation of phenol red (PR) and bisphenol A (BPA) in aqueous media. Electronic supplementary information (ESI) available: Optimization of the mass ratios of HA to CNTs and the reaction pH conditions for Fe loading; scanning electron microscope (SEM), UV-Vis-near-infrared, Raman spectroscopy, Fourier transform infrared spectroscopy (FTIR)