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PubMed1977

[Role of iron ions on tannin-iron method histochemical specificity (author's transl)].

In this work is studied the tannin-iron method specificity when the ferrous chloride is replaced by other iron compounds. Nervous tissue and rat duodenum cuts are used. Cuts were treated with tannic acid and after with FeCl3; FeCl2; FeOHCl2; FeAc2; Fe2O3; FeSO4; NH4Fe(SO4)2 or colloidal iron solution. Dilution effect from every one of aforementioned iron compounds too is studied. The obtained results with those furnished by the OTA method by using the tannic acid in identical conditions are compared. Also several treatments of blockade were carried-out. The obtained results prove that iron ions play a different role in the mucins staining than in other demonstrable substances coloration in the nervous tissue. In the same way evidences that the iron ion that joins the mucins in the tannin-iron method is the FeOH++ ion were obtained.

Animals↗
PubMed2007

Improved iron bioavailability in an oat-based beverage: the combined effect of citric acid addition, dephytinization and iron supplementation.

BACKGROUND: Iron deficiency in children is a major worldwide nutritional problem. An oat beverage was developed for 1- to 3-year-old children and different treatments were used to improve the iron bioavailability. AIM OF THE STUDY: To investigate the effects of citric acid addition, phytase treatment and supplementation with different iron compounds on non-heme iron absorption in human from a mineral-supplemented oat-based beverage. METHODS: A 240 g portion of a 55Fe-labeled test product (T) or a 59Fe-labeled reference dose (R) was served as breakfast after overnight fasting on four consecutive days in the order of TRRT. On day 18 the retention of 59Fe was measured by a whole-body counter and the erythrocytes uptake of 55Fe and 59Fe by a liquid-scintillation counter. Forty-two healthy subjects (men and women) were randomized into four study groups, members of each being given one of the studied four products (A, B, C, and D) supplemented with Fe (1.3 mg/portion), Zn, Ca, Se and P. Ferric ammonium citrate (FeAC) was added to products A, B, and C and ferric pyrophosphate (FePP) to product D. Citric acid (60 mg/portion) was added to products B, C, and D and phytase treatment applied to products C and D. RESULTS: Citric acid improved iron absorption by 54% from 3.9% in product A to 6.0% in product B (p = 0.051). Phytase treatment increased iron absorption by 78% (from 6.0 to 10.7%, p = 0.003) by reducing the phytate-phosphorus content per portion from 16.3 mg in product B to 2.8 mg in product C. The two compounds gave similar iron absorption rates (p = 0.916). CONCLUSIONS: A combination of citric acid addition, dephytinization and iron supplementation significantly increased the iron absorption in an oat-based beverage. Such a beverage can be useful in the prevention of iron deficiency in 1- to 3-year-old children.

6-Phytase↗
PubMed1995

Iron from complex salts and its bioavailability to rats.

Complex iron compounds are being used as iron suppliers. Bioavailability of their iron was tested through several parameters. A biological iron prophylactic study in rats was simultaneously carried out with three of these iron complexes products: ferric orthophosphate, iron sodium EDTA and iron glycine chelate. Their iron biodisponibility was compared to that of ferrous sulfate. Five low iron diets were prepared according to AOAC method. Four of them were enriched to a level of 20 mg Fe/kg, with ferrous sulfate and the 3 iron complexes salts under study. These diets were offered to 5 groups of 6 weanling rats each in an iron prophylactic test. Food intake was measured during 5 weeks, weight checked weekly, blood and liver collected for analyses. Weight gain, hemoglobin, hematocrit, transferrin saturation, iron hemoglobin, biodisponibility and relative iron biological values were calculated. The prophylactic iron rat assay proved to be a feasible and practical model to test and compare iron salts biodisponibility. NaFeEDTA and iron aminochelate produced similar results as ferrous sulfate and their iron has a high biological value for the rats. Orthophosphate iron had lower biological value when compared to the reference standard ferrous sulfate and the other complex products studied.

Animals↗
PubMed1976

Iron as a replacement for mucin in the establishment of meningococcal infection in mice.

Experimental infection of mice with Neisseria meningitidis was established by the injection of the bacteria suspended in solutions of various iron compounds. The progressive and fatal infection caused by otherwise non-lethal doses of organisms was produced in these mice after prior injection with ferrous sulphate or concomitant injection with iron sorbitol citrate or iron dextran. Reduction in LD50 to levels at least comparable to those obtained in the mucin challenge system was achieved; in some serogroups of N. meningitidis the LD50 was decreased more than a million fold. The results suggest that iron, which is a component of hog gastric mucin, is a factor involved in the establishment of meningococcal infection in mice. Use of iron compounds as injection medium offers a more advantageous system than mucin, since controlled administration of chemically defined substances occurs.

Animals↗
PubMed1998

An in vitro model for analysis of oxidative death in primary mouse astrocytes.

Astrocytes provide a vital protective function in the brain. These cells are also vulnerable to oxidative stress, thus their loss of function could contribute to neurodegeneration. The goal of this study is to develop a cell culture model to study oxidative stress in astrocytes. Enriched astrocytic cultures were generated from neonatal mice. tertiary-butyl hydroperoxide (t-bOOH) was used as an exogenous peroxide and lactate dehydrogenase (LDH) release as a measure of loss of viability. Exposure to t-bOOH resulted in a linear increase in astrocytic death reaching 91.2% after 4 h exposure. That cell death was due to oxidative injury, was shown by the ability of the antioxidant N,N'-diphenyl-1,4-phenylenediamine (DPPD) to protect the t-bOOH treated cells. The involvement of iron in cell toxicity was demonstrated by the ability of the iron specific chelator desferal (DF) to completely prevent t-bOOH induced LDH release. Cells treated with a lipid soluble iron compound 3,5, 5-trimethyl (hexanoyl) ferrocene (TMH-Ferrocene), were more vulnerable to t-bOOH whereas neither ferrous ammonium sulfate (FAS) nor ferric ammonium citrate (FAC) had an effect. The increased sensitivity of the cells exposed to TMHF was reversible with the iron chelator desferal. Addition of recombinant human heavy chain ferritin or human apo-transferrin (Tf) did not alter LDH release. Electron microscopic analysis indicated astrocytes exposed to t-bOOH exhibited mitochondrial swelling prior to cell death (lactate dehydrogenase release). Additional increases in mitochondrial swelling were seen when the astrocytes were exposed to the lipophilic iron compound TMH-ferrocene and t-bOOH. These studies show that astrocytes are exquisitely sensitive to oxidative stress and that their vulnerability is related to and enhanced by iron. Decreased mitochondrial function in response to oxidative stress may precede cell death.

Animals↗
PubMed2000

An evaluation of EDTA compounds for iron fortification of cereal-based foods.

Fe absorption was measured in adult human subjects consuming different cereal foods fortified with radiolabelled FeSO4, ferrous fumarate or NaFeEDTA, or with radiolabelled FeSO4 or ferric pyrophosphate in combination with different concentrations of Na2EDTA. Mean Fe absorption from wheat, wheat-soyabean and quinoa (Chenopodium quinoa) infant cereals fortified with FeSO4 or ferrous fumarate ranged from 0.6 to 2.2%. For each infant cereal, mean Fe absorption from ferrous fumarate was similar to that from FeSO4 (absorption ratio 0.91-1.28). Mean Fe absorption from FeSO4-fortified bread rolls was 1.0% when made from high-extraction wheat flour and 5.7% when made from low-extraction wheat flour. Fe absorption from infant cereals and bread rolls fortified with NaFeEDTA was 1.9-3.9 times greater than when the same product was fortified with FeSO4. Both high phytate content and consumption of tea decreased Fe absorption from the NaFeEDTA-fortified rolls. When Na2EDTA up to a 1:1 molar ratio (EDTA:Fe) was added to FeSO4-fortified wheat cereal and wheat-soyabean cereal mean Fe absorption from the wheat cereal increased from 1.0% to a maximum of 5.7% at a molar ratio of 0.67:1, and from the wheat-soyabean cereal from 0.7% to a maximum of 2.9% at a molar ratio of 1:1. Adding Na2EDTA to ferric pyrophosphate-fortified wheat cereal did not significantly increase absorption (P > 0.05). We conclude that Fe absorption is higher from cereal foods fortified with NaFeEDTA than when fortified with FeSO4 or ferrous fumarate, and that Na2EDTA can be added to cereal foods to enhance absorption of soluble Fe-fortification compounds such as FeSO4.

Absorption↗
PubMed2004

Ferrichrome in Schizosaccharomyces pombe--an iron transport and iron storage compound.

Schizosaccharomyces pombe has been assumed not to produce siderophores. Nevertheless, the genomic sequence of this fission yeast revealed the presence of siderophore biosynthetic genes for hydroxamates. Applying a bioassay based on an Aspergillus nidulans strain deficient in siderophore biosynthesis, and using reversed-phase HPLC and mass spectrometry analysis, we demonstrate that S. pombe excretes and accumulates intracellularly the hydroxamate-type siderophore ferrichrome. Under iron-limiting conditions, the cellular ferrichrome pool was present in the desferri-form, while under iron-richconditions, in the ferri-form. In contrast to S. pombe, hydroxamate-type siderophores could not be detected intwo other yeast species, Saccharomyces cerevisiae and Candida albicans.

Amino Acid Sequence↗
PubMed1977

Differentiated regions of human placental cell surface associated with exchange of materials between maternal and foetal blood: a new organelle and the binding of iron.

To elucidate the method of uptake of a neutral iron compound into the placenta, isolated human chorionic villi were incubated in a medium containing the substance and were fixed at intervals and subsequently examined using transmission electron microscopy. None of the specimens examined showed evidence of vesicular transport in either micro- or macro-pinocytic vesicles which were either coated or smooth-surfaced. Iron uptake may involve attachment of particles to differentiated regions of the cell surface of the syncytiotrophoblast. These differentiated zones in the syncytial cell surface are composed of morphological distinct parts and therefore probably merit classification as an organelle. Our interpretation of the organelle's structure is that it is flattened, with a maximum distance across of about 30 nm in the plane of the membrane. It is of otherwise uncertain shape but possesses a multilaminar structure. The external layer is apparently composed of the iron compound to be taken up. Beneath this is an electron-lucent layer possibly composed of glycoacalyx. The next innermost layer is continuous with the trilaminar unit membrane of the cell surface, however no trilaminar appearance is observed within the organelle. Beneath the membrane layer is an electron-dense plaque of amorphous material. Occasionally in favourable sections there is the suggestion of a thin electron-lucent strip interposed between the dense plaque and the membrane layer. The whole structure is composed therefore of 4 or 5 different regions. One possible function is that of initial binding in a process of active as opposed to passive transport of iron into the cell.

Binding Sites↗
PubMed1992

MR lymphography with iron oxide compound AMI-227: studies in ferrets with filariasis.

OBJECTIVE: The purpose of this study was to assess the MR lymphographic potential of AMI-227 to reduce the signal intensity of hyperplastic inflammatory lymph nodes by using ferrets with filariasis as the animal model. Both interstitial and IV modes of administration were studied. MATERIALS AND METHODS: Twelve ferrets were infected with the filaria Brugia malayi and six control ferrets were injected with super-paramagnetic iron oxide AMI-227, either interstitially or IV. Signal intensities of the left popliteal lymph node, left hamstring muscle, and left inguinal fat were measured before, 48 hr after, and up to 138 days after contrast injection with the use of both spin-echo and gradient-echo techniques. The signal intensity data were statistically analyzed. The lymph nodes, liver, spleen, and lungs were studied with light and electron microscopy. RESULTS: Forty-eight hours after the interstitial injection of AMI-227, the signal intensities of the ipsilateral popliteal nodes of the infected and control ferrets were significantly reduced (p less than .0005) without significant changes in the signal intensities of the surrounding tissues on both spin-echo and gradient-echo MR images. No nodal signal reduction occurred with the IV route of injection in ferrets. Light microscopy revealed iron to be localized within nodal marginal zones exclusively. Lymphatic trunks were visualized after interstitial injection. Signal reduction persisted to our end point at 138 days. CONCLUSION: AMI-227 shows regional specificity with significant enhancement of nodal structures and demonstrates potential as an interstitial MR lymphographic agent.

Animals↗
PubMed1991

Ferro-mitogens: iron-containing compounds with lymphocyte-stimulatory properties.

Ferric ammonium citrate (FAC) is nonmitogenic for human peripheral blood mononuclear cells (PBM) but has a potent mitogenic activity in the presence of IL-2. FAC in the presence of IL-2 increases the number of human peripheral blood mononuclear cells (PBM) expressing receptors for IL-2 and transferrin. FAC also markedly stimulates human PBM treated with supraoptimal, nonmitogenic concentrations of Con A. FAC, in the presence of IL-2, is a T-cell mitogen with a stringent requirement for macrophages. FAC stimulates the production of TNF-alpha and IFN-gamma in human PBM, and this effect is potentiated by IL-2. Thiourea and 3-amino-1,2,4-triazole selectively inhibit mitogenesis induced by FAC, indicating that oxygen radicals or peroxidase may mediate the triggering signal induced by this mitogen. In addition to hemin, as we have previously reported, and FAC, a variety of iron-containing proteins have lymphocyte stimulatory properties in combination with IL-2. They include horseradish peroxidase, cytochrome c, myoglobin, and transferrin. We have given the name ferro-mitogens to this group of compounds.

Antigens, Surface↗