Divalent Form Research Articles

Copper: Its biologicalrole and toxicity

Universally the demand for copper is one of the largest next only to iron and aluminium. Copper occurs in the soil mostly in divalent form. The Cu ion is present as inorganic and organic positively charged groups and is dissolved in the soil system as Cu2+ and organic Cu complexes. The divalent Cu ion has a strong affinity to soil organic matter compared with other divalent cationsin order of following sequence: Cu > Ni >Pb> Co > Ca > Zn >Mn> Mg. The Cu2+ concentration in the soil solution are governed by Cu adsorption to organic and inorganic soil particles. Copper can be released into the environment by both natural sources and human activities. When copper ends up in soil it strongly attaches to organic matter and minerals. Copper can seriously influence the productivity of certain farmlands, depending upon the acidity of the soil and the presence of organic matter. Under physiological conditions, the metal Cu can be converted to two common forms, the reduced Cu (I) state and the oxidized Cu (II) state. Mechanisms of Cu2+ion toxicity with relation to proteins, enzymes, nucleic acids and metabolites leads to significant changes in them and decreased feasibility. Similarly, an effect of toxicity is also observed in respiration. Copper is mandatory for the growth and metabolism of microorganisms since it is a cofactor for numerous enzymes. Under anaerobic conditions, the conversion of Cu2+ to Cu+ can be responsible for decreased survival of bacterial species. The plants grown under copper deficiency also show impairment in the photosynthetic transport chain. Copper toxicity can occur from the repeated use of fungicides that contain copper. The symptoms of copper deficiency are cupping and slight chlorosis of either the whole leaf or between the veins of the new leaves. Recently, synthesis of copper nanoparticles is being carried out using chemical and biological methods. The impact of copper nanoparticles depends on size, component and have some adverse result. However, the potential risk of use of copper nanoparticles must be assured before releasing them.

Molecular mechanism of substrate selectivity of the arginine-agmatine Antiporter AdiC

The arginine-agmatine antiporter (AdiC) is a component of an acid resistance system developed by enteric bacteria to resist gastric acidity. In order to avoid neutral proton antiport, the monovalent form of arginine, about as abundant as its divalent form under acidic conditions, should be selectively bound by AdiC for transport into the cytosol. In this study, we shed light on the mechanism through which AdiC distinguishes Arg+ from Arg2+ of arginine by investigating the binding of both forms in addition to that of divalent agmatine, using a combination of molecular dynamics simulations with molecular and quantum mechanics calculations. We show that AdiC indeed preferentially binds Arg+. The weaker binding of divalent compounds results mostly from their greater tendency to remain hydrated than Arg+. Our data suggests that the binding of Arg+ promotes the deprotonation of Glu208, a gating residue, which in turn reinforces its interactions with AdiC, leading to longer residence times of Arg+ in the binding site. Although the total electric charge of the ligand appears to be the determinant factor in the discrimination process, two local interactions formed with Trp293, another gating residue of the binding site, also contribute to the selection mechanism: a cation-π interaction with the guanidinium group of Arg+ and an anion-π interaction involving Glu208.

Insight into the sorption mechanism of metformin and its transformation product guanylurea in pastoral soils and model sorbents

Single solute sorption mechanisms of metformin (MET) and guanylurea (GUA) were investigated in six soils and three model sorbents (kaolinite, bentonite and humic acid) at varying initial pH and background electrolyte (Ca2+) concentrations. Electrostatic interaction and cation exchange were proposed as mechanisms of MET sorption. At initial solution pH between pKa1 and pKa2, electrostatic interaction is the dominating mechanism of MET sorption. However, as pH approaches pKa1, cation exchange becomes a significant mechanism of sorption as evidenced by the increased distribution coefficient (Kd) values in Matawhero (130-fold) and Nelson (2000-fold) soils with high cation exchange capacities (CEC) and permanently negative charged sites and when equilibrium pH < pKa1 where the divalent cationic form dominates in the solution. Furthermore, results showed higher sorption of MET on bentonite with effective distribution coefficient (Kdeff) value of 14.92 L/kg with high permanent negative charges than on kaolinite (Kdeff = 6.70 L/kg), a variable charge clay. Increased MET sorption at low equilibrium pH on kaolinite (Kdeff = 2.3 × 107 L/kg) and humic acid (Kdeff = 20.86 L/kg) further suggest cation exchange is also possible at pH < pKa1. On the other hand, two lines of evidence suggest cation exchange as an important mechanism of GUA sorption: (a) the positive correlation between cation exchange capacity and Kdeff values and (b) decreased Kdeff values as the Ca2+ concentration in solution was increased in all soils. Biosolids amendment of three soils resulted in contrasting effects on sorption affinities with a decrease for MET and increase for GUA, further confirming sorption mechanisms and significance of solution pH and CEC on the sorption of MET and GUA, respectively.

Biological Efficiency of the Prepupae Hermetia illucens in the Diet of the Young Mozambique Tilapia Oreochromis mossambicus

It has been noted that the introduction of small doses of dry prepupae of Hermetia illucens flies into the diet of the young Mozambique tilapia Oreochromis mossambicus (0.5 g/kg feed) had a positive effect on the growth and development of fish. It was found that the average daily gain in the experimental group was 0.7 g. It was established that the blood biochemical parameters were within the norm in the fish of all groups; however, in the experimental tilapia, the erythrocyte sedimentation rate was significantly lower and a tendency to increase in the amount of hemoglobin and glucose was noted. It was revealed that in the seminiferous tubules of fish in the experimental group, the number of mature sperm was 5.9 times higher compared with the control, indicating an increase in the rate of spermatogenesis. It is assumed that the observed effects are due to the high content of manganese in the prepupae present in a biologically active divalent form.

Cytotoxicity of Heavy Metals to A Thyroid Carcinoma Cell Line

Multiple heavy metals are known to cause renal insufficiency and necrosis, details on the toxic mechanism are still lacking. We investigated the cytotoxicity of 12 heavy metals to the 8505C thyroid cancer cells at concentrations of 10−3–105 μM. Notable decreases in cell viability were observed in exposures to four metals in the divalent cation form (nickel, copper, zinc, and cadmium) at concentrations ≥ 1 μM. The effect of cadmium on cell death was substantial. In addition, the toxicity of 3 μM cadmium to the cells was inhibited by the addition of high concentrations (300 μM) of calcium or selenium, but intracellular levels of cadmium increased.

Sulfur Atom in its Bound State Is a Unique Element Involved in Physiological Functions in Mammals.

It was in the 1950s that the term polysulfide or persulfide was introduced in biological studies. The unfamiliar term “sulfane sulfur” sometimes appeared in papers published in the 1970s, and was defined in the review article by Westley in 1983. In the article, sulfane sulfur is described as sulfur atoms that are covalently bound only with sulfur atoms, and as this explanation was somewhat difficult to comprehend, it was not generally accepted. Thus, in the early 1990s, we redefined these sulfur species as “bound sulfur”, which easily converts to hydrogen sulfide on reduction with a thiol reducing agent. In other words, bound sulfur refers to a sulfur atom that exists in a zero to divalent form (0 to −2). The first part of this review focuses on the fluorescent derivatization HPLC method—which we developed for measurement of bound sulfur—and explains the distribution of bound sulfur and the hydrogen sulfide-producing ability of various tissues, as clarified by this method. Next, we discuss diverse physiological functions and involvement of polysulfide, a typical type of bound sulfur, in the redox regulation system. Additionally, we also address its possible physiological role in the central nervous system, based on its action of scavenging reactive carbonyl compounds.

Characterization of a high-affinity sialic acid-specific CBM40 from Clostridium perfringens and engineering of a divalent form.

CBMs (carbohydrate-binding modules) are a class of polypeptides usually associated with carbohydrate-active enzymatic sites. We have characterized a new member of the CBM40 family, coded from a section of the gene NanI from Clostridium perfringens Glycan arrays revealed its preference towards α(2,3)-linked sialosides, which was confirmed and quantified by calorimetric studies. The CBM40 binds to α(2,3)-sialyl-lactose with a Kd of ∼30μM, the highest affinity value for this class of proteins. Inspired by lectins' structure and their arrangement as multimeric proteins, we have engineered a dimeric form of the CBM, and using SPR (surface plasmon resonance) we have observed 6-11-fold binding increases due to the avidity affect. The structures of the CBM, resolved by X-ray crystallography, in complex with α(2,3)- or α(2,6)-sialyl-lactose explain its binding specificity and unusually strong binding.

Synthetic ligands of death receptor 5 display a cell-selective agonistic effect at different oligomerization levels.

DR4 (Death Receptor 4) and DR5 (Death Receptor 5) are two potential targets for cancer therapy due to their ability to trigger apoptosis of cancer cells, but not normal ones, when activated by their cognate ligand TRAIL (TNF related apoptosis-inducing ligand). Therapies based on soluble recombinant TRAIL or agonist antibodies directed against one of the receptors are currently under clinical trials. However, TRAIL-R positive tumor cells are frequently resistant to TRAIL induced apoptosis. The precise mechanisms of this resistance are still not entirely understood. We have previously reported on synthetic peptides that bind to DR5 (TRAILmim/DR5) and induce tumor cell apoptosis in vitro and in vivo. Here, we showed that while hexameric soluble TRAIL is able to efficiently kill the DR5 positive lymphoma Jurkat or the carcinoma HCT116, these cells are resistant to apoptosis induced by the divalent form of TRAILmim/DR5 and are poorly sensitive to apoptosis induced by an anti-DR5 agonist monoclonal antibody. This resistance can be restored by the cross-linking of anti-DR5 agonist antibody but not by the cross-linking of the divalent form of TRAILmim/DR5. Interestingly, the divalent form of TRAILmim/DR5 that induced apoptosis of DR5 positive BJAB cells, acts as an inhibitor of TRAIL-induced apoptosis on Jurkat and HCT116 cells. The rapid internalization of DR5 observed when treated with divalent form of TRAILmim/DR5 could explain the antagonist activity of the ligand on Jurkat and HCT116 cells but also highlights the independence of the mechanisms responsible for internalization and activation when triggering the DR5 apoptotic cascade.

RESOLFT Nanoscopy of Fixed Cells Using a Z-Domain Based Fusion Protein for Labelling.

RESOLFT super-resolution microscopy allows subdiffraction resolution imaging of living cells using low intensities of light. It relies on the light-driven switching of reversible switchable fluorescent proteins (RSFPs). So far, RESOLFT imaging was restricted to living cells, because chemical fixation typically affects the switching characteristics of RSFPs. In this study we created a fusion construct (FLASR) consisting of the RSFP rsEGFP2 and the divalent form of the antibody binding Z domain from protein A. FLASR can be used analogous to secondary antibodies in conventional immunochemistry, facilitating simple and robust sample preparation. We demonstrate RESOLFT super-resolution microscopy on chemically fixed mammalian cells. The approach may be extended to other super-resolution approaches requiring fluorescent proteins in an aqueous environment.

Влияние сульфата железа на биосинтез внеклеточных метаболитов пропионовокислыми бактериями

In the work, activated cultures of propionic acid bacteria were found to exhibit high antimutagenic activity and adhesion properties, synthesize considerable amount of corrinoids and heme-containing enzymes. Increase of iron concentration in the medium was shown to intensify synthesis of extracellular metabolites promoting adaptation of the culture to the metal. Optimal technological parameters for isolation of casein phosphopeptides were determined. Ability of phosphopeptides to efficiently solubilize divalent iron was confirmed. Relationship between iron concentration and extent of solubilization was established. Iron chelated with casein phosphopeptides was noted to stay in divalent form for prolonged period.

Tuning of magnetic and transport properties in Bi2Te3by divalent Fe doping

We report the doping effect of a magnetic Fe ion in Bi${}_{2}$Te${}_{3}$, that is, Bi${}_{2\ensuremath{-}x}$Fe${}_{x}$Te${}_{3}$ ($x$ $=$ 0, 0.08, 0.15, 0.2, 0.25, and 0.3). The paramagnetic magnetization data reveal that the Fe ions are doped in the divalent form. The Fe${}^{2+}$ state substituted for Bi${}^{3+}$ can create hole donors, which compensate for the electron dopants of Bi${}_{2}$Te${}_{3}$ with a small amount of Te excess. This causes the $n$-type carrier density to be decreased with increasing $x$, and finally be changed to $p$ type at $x$ $=$ 0.3, where the carrier mobility suddenly drops and the electrical resistivity abruptly increases. These results are consistent with angle-resolved photoemission spectroscopy experiments. The Fermi level shifts downward with increasing $x$. Furthermore, we find a larger spin polarization for the Fe-doped Bi${}_{2}$Te${}_{3}$ samples, which is crucial for future spintronics applications.

Glutaraldehyde-crosslinked chitosan beads for sorptive separation of Au(III) and Pd(II): Opening a way to design reduction-coupled selectivity-tunable sorbents for separation of precious metals

Glutaraldehyde (GA)-crosslinked chitosan beads (GA-CS) are prepared with coagulating solution containing sodium tripolyphosphate and GA, and used for the adsorption of metals from binary-metal solution Au(III) and Pd(II). GA-CS exhibited selective sorption of Au(III) in the Au(III)–Pd(II) mixture. X-ray diffraction analyses showed that Au(III) was reduced to Au(0) following sorption, while Pd(II) was present as unreduced divalent form. Increased GA led to more selectivity toward Au(III), indicating that Au(III) selectivity is attributed to reduction-couple sorption of Au(III) with a reducing agent GA. Furthermore, a 2-step desorption process enabled selective recovery of Pd and Au using 5M HCl and 0.5M thiourea–1M HCl, respectively, leading to pure Pd(II) and Au(III)-enriched solutions. This finding may open a new way to design reduction-coupled selectivity-tunable metal sorbents by combination of redox potentials of metal ions and reducing agents.

Ni speciation in tea infusions by monolithic chromatography—ICP-MS and Q-TOF-MS

For humans, Ni is not considered to be an essential trace element. Its compounds, at levels present in foodstuffs and drinks, are generally considered to be safe for consumption, but for individuals who already suffer from contact allergy to Ni and may be subject to develop systemic reactions from its dietary ingestion, dietary exposure to Ni must be kept under control. Being the second most popular beverage, tea is a potential source of dietary Ni. Present knowledge on its speciation in tea infusions is poor. Therefore, complete speciation analysis, consisting of separation by liquid chromatography using a weak CIM DEAE-1 monolithic column, "on-line" detection by inductively coupled plasma mass spectrometry (ICP-MS) and "off-line" identification of ligands by hybrid quadrupole time-of-flight mass spectrometry (Q-TOF MS), was implemented for the first time to study Ni speciation in tea infusions. Total concentrations of Ni in dry leaves of white, green, oolong and black tea (Camellia sinensis) and flowers of herbal chamomile (Matricaria chamomilla) and hibiscus (Hibiscus sabdariffa) tea were determined after microwave digestion by ICP-MS. They lay between 1.21 and 14.4 mg kg(-1). Good agreement between the determined and the certified values of the Ni content in the standard reference material SRM 1573a tomato leaves confirmed the accuracy of the total Ni determination. During the infusion process, up to 85 % of Ni was extracted from tea leaves or flowers. Separation of Ni species was completed in 10 min by applying aqueous linear gradient elution with 0.6 mol L(-1) NH(4)NO(3). Ni was found to be present in the chromatographic fraction in which quinic acid was identified by Q-TOF in all the tea infusions analysed, which had pH values between 5.6 and 6.0. The only exception was the infusion of hibiscus tea with a pH of 2.7, where results of speciation analysis showed that Ni is present in its divalent ionic form.

Reactions of copper macrocycles with antioxidants and HOCl: potential for biological redox sensing

A series of simple copper N(2)S(2) macrocycles were examined for their potential as biological redox sensors, following previous characterization of their redox potentials and crystal structures. The divalent species were reduced by glutathione or ascorbate at a biologically relevant pH in aqueous buffer. A less efficient reduction was also achieved by vitamin E in DMSO. Oxidation of the corresponding univalent copper species by sodium hypochlorite resulted in only partial (~65%) recovery of the divalent form. This was concluded to be due to competition between metal oxidation and ligand oxidation, which is believed to contribute to macrocycle demetallation. Electrospray mass spectrometry confirmed that ligand oxidation had occurred. Moreover, the macrocyclic complexes could be demetallated by incubation with EDTA and bovine serum albumin, demonstrating that they would be inappropriate for use in biological systems. The susceptibility to oxidation and demetallation was hypothesized to be due to oxidation of the secondary amines. Consequently these were modified to incorporate additional oxygen donor atoms. This modification led to greater resistance to demetallation and ligand oxidation, providing a better platform for further development of copper macrocycles as redox sensors for use in biological systems.

Buyer beware! Doctor be aware!—Answers

Acute hyperphosphatemia with hypocalcemic tetany from exogenous phosphate load was diagnosed. The serum phosphorous level was 45.2 mg/dl, total calcium 5.1 mg/dl and ionized calcium 1.83mg/dl (normal range 4.40–5.40 mg/dl). An adult Fleet® enema (C.B. Fleet Co., Lynchburg, VA) has a volume of 118 ml and contains 19 g of monobasic sodium phosphate monohydrate, 7 g of dibasic sodium phosphate heptahydrate and 4.4 g of sodium [1]. Hypocalcemia is induced by calcium complexing with phosphate, and the magnitude of hypocalcemia is proportional to the degree by which the solubility product of calcium phosphate is exceeded. Although the exact threshold is impossible to determine, a product as low as 60 mg/dl has been associated with increased visceral calcification [2, 3]. Phosphorous is the sixth most abundant element in the human body, and under normal conditions most total body phosphorous exists in the bone in the divalent form (HPO4 ). Of the remaining phosphorous 10 % exists intracellularly, and only 1 % is found in the extracellular fluid of which 15 % is protein bound and another 5 % is complexed as salts with cations such as sodium, calcium and magnesium [4, 5]. Active absorption of dietary phosphorous occurs in the small intestine (duodenum and jejunum) via sodium phosphate cotransporter 2b (NaPi2b). Passive absorption takes place throughout the intestine, including the colon. As a reference, the typical adult diet contains 1 g of phosphorous daily. The recommended elemental phosphorous intake for a 6-year-old child is 500 mg per day. Our patient received 15.8 g (488.5 mmol) of elemental phosphate within 12 h. Control of plasma phosphate is normally maintained by altering renal excretion or redistribution within the body compartments. Phosphate is freely filtered at the glomerulus, and 85 % is reabsorbed into the blood at the level of the proximal tubule. Phosphate enters the proximal tubule cell against an electrical gradient via the NaPi2a and NaPi2c transporters, both of which are located along the brush border membrane [5]. Inhibition of proximal tubule reabsorption produces phosphaturia, which not uncommonly can cause hypophosphatemia. In our case, the large exogenous phosphorous load overwhelmed the limited ability of the gut and kidney to regulate phosphorous absorption and excretion. Hyperphosphatemia occurs from exogenous sources, as in our case, or from endogenous sources, such as tumor lysis syndrome or rhabdomyolysis. In clinical medicine, chronic kidney disease is the most common cause. Severe This article refers to the article that can be found at http://dx/doi.org/ 10.1007/s00467-012-2338-y E. Anyaegbu : T. Keefe Davis (*) :K. Hruska :A. Beck (*) Division of Nephrology, Department of Pediatrics, Washington University School of Medicine, Box 8208, 660 S. Euclid Ave, St. Louis, MO 63110, USA e-mail: davis_tk@kids.wustl.edu e-mail: beck_a@kids.wustl.edu

Two heptadentate Co(III) and Mn(III) complexes with partially deprotonated cyclen derivative bearing four hydroxypropyl pendants: structure, DNA binding and DNA cleavage

Two new complexes, (CoIII)2(H3L−)2(0.5H2O)2(ClO4)4 (I) and (MnIII)2(H3L−)2(0.5H2O)2 (ClO4)4 (II), were synthesized and crystallographically characterized [H4L = 1,4,7,10‐tetra‐(2‐hydroxypropyl)‐l,4,7,10‐tetraazacyclododecane] using electrospray ionization mass spectrometry and X‐ray photoelectron spectrometery. The characterizations confirmed that the valences of the metal ions increased from divalent to trivalent due to deprotonation of one OH group (H4L was in the form of H3L−). Owing to the instability of Co(III) and Mn(III) in both air and in solution, they preferred to exist in divalent form. The two heptadentate complexes are extraordinary in that the chiral pendants of the complexes are different in configuration. Spectroscopic studies, viscosity measurements, thermal denaturation experiments and circular dichroism spectra demonstrated that the complexes were prone to interact with DNA by groove binding. At micromolar concentrations and under physiological conditions, the two complexes were able to oxidatively cleave the supercoiled pUC19 plasmid DNA into its nicked and linear forms. Mechanistic studies using various additives suggest the complexes had structures different from those of other inorganic complexes. These are the first reported inorganic complexes not containing planar aromatic ligands and yet binding at the major groove. Copyright © 2012 John Wiley &amp; Sons, Ltd.

X-ray induced Sm3+ to Sm2+ conversion in fluorophosphate and fluoroaluminate glasses for the monitoring of high-doses in microbeam radiation therapy

Fluorophosphate and fluoroaluminate glasses doped with trivalent samarium were evaluated as sensors of x-ray radiation for microbeam radiation therapy at the Canadian Light Source using the conversion of trivalent Sm3+ to the divalent form Sm2+. Both types of glasses show similar conversion rates and may be used as a linear sensor up to ∼150 Gy and as a nonlinear sensor up to ∼2400 Gy, where saturation is reached. Experiments with a multi-slit collimator show high spatial resolution of the conversion pattern; the pattern was acquired by a confocal fluorescence microscopy technique. The effects of previous x-ray exposure may be erased by annealing at temperatures exceeding the glass transition temperature Tg while annealing at TA &amp;lt; Tg enhances the Sm conversion. This enhancement is explained by a thermally stimulated relaxation of host glass ionic matrix surrounding x-ray induced Sm2+ ions. In addition, some of the Sm3+-doped glasses were codoped with Eu2+-ions but the results show that there is no marked improvement in the conversion efficiency by the introduction of Eu2+.

A special role of phosphate in the stability of lactate dehydrogenase against destruction by a polyelectrolyte

X-ray analysis shows the presence of specific anion-binding sites in proteins for sulfate, citrate and phosphate ions, but the functional role of these anions is not always clear. Thus, it is unknown which of the two types, mono- or divalent phosphate, plays an important role in the stability of proteins to stress effects on cells. In the present work, the influence of phosphate, sulfate, and chloride salt on the stability of lactate dehydrogenase (LDH) to its destruction by poly(styrenesulphonate) (PSS) was investigated by the methods of steady-state kinetics and the own protein fluorescence. The analysis was based on the differences between the influence of phosphate and sulfate ions on the process at two pH values, 6.2 and 7.0, at which the ratio of mono- and divalent phosphate changed, whereas sulfate remained in the divalent form. It was shown that the difference between the influence of phosphate and sulfate ions increased with increasing pH, which indicates that divalent phosphate ions much more effectively stabilized LDH compared to sulfate and monovalent phosphate. The differences in the effect of sulfate and chloride salts on the protein corresponded to differences in ionic strength of their solutions. The study of the own fluorescence of LDH in the complex with PSS showed that the rate of fluorescence quenching and the amplitude of the fast stage significantly decreased with increasing concentration of divalent phosphate in solution, as compared to the same effect in the presence of sulfate anions. The conclusion was made that, from two anion-binding sites in the LDH molecule, the intersubunit center is most important in stabilizing the protein to the destruction by polyelectrolyte, and from two phosphate anions, hydrophosphate HPO4(-2) plays the stabilizing role.

Hydroxyl radical-modified fibrinogen as a marker of thrombosis: the role of iron

Excessive free iron in blood and in organ tissues (so called iron overload) has been observed in degenerative diseases such as atherosclerosis, cancer, neurological, and certain autoimmune diseases, in which fibrin-like deposits are also found. Although most of the body iron is bound to hemoglobin and myoglobin in a divalent ferrous form, a certain amount of iron exists in blood as a trivalent (ferric) ion. This particular chemical state of iron has been shown to be toxic to the human body when not controlled by endogenous and/or dietary chelating agents. Experiments described in this paper show for the first time that ferric ions (Fe3+) can generate hydroxyl radicals without participation of any redox agent, thus making it a special case of the Fenton reaction. Ferric chloride was also demonstrated to induce aggregation of purified fibrinogen at the same molar concentrations that were used for the generation of hydroxyl radicals. Iron-aggregated fibrinogen, by contrast to native molecule, could not be dissociated into polypeptide subunit chains as shown in a polyacrylamide gel electrophoresis. The mechanism of this phenomenon is very likely based on hydroxyl radical-induced modification of fibrinogen tertiary structure with the formation of insoluble aggregates resistant to enzymatic and chemical degradations. Soluble modified fibrinogen species can be determined in blood of thrombotic patients by the reaction with protamine sulfate and/or by scanning electron microscopy. In view of these findings, it is postulated that iron-induced alterations in fibrinogen structure is involved in pathogenesis of certain degenerative diseases associated with iron overload and persistent thrombosis. It is concluded that the detection of hydroxyl radical-modified fibrinogen may be utilized as a marker of a thrombotic condition in human subjects.

Cross‐reactive antigens for natural IgE antibodies: allergens with the potential to transform a dormant to an active allergic response?

Cross‐reactive antigens for natural IgE antibodies: allergens with the potential to transform a dormant to an active allergic response?