Μg Of Iron Research Articles

Dietary Iron Levels and Hypoxia Independently affect Iron Absorption in Mice

The effect of dietary iron levels on the hypoxic response of iron absorption was investigated by feeding mice diets of different iron composition and determining iron absorption. Eight groups of mice were fed a purified diet consisting of casein, corn oil and sucrose with vitamins and iron-free mineral supplements. Groups A–D were fed a nonpurified diet until 6 wk old and then switched to purified diet for 4 d. Groups E–H were fed purified diet for 4 wk from weaning. Groups C, D, G and H were exposed to hypoxia (53.3 kPa) for the last 3 d of the study. Groups A, C, E and G received the low iron purified diet (<1 mg iron per kg); the other groups received the same diet supplemented with 62 mg/kg iron as FeCl3·6H2O. Hypoxic exposure raised iron absorption (P < 0.001) by a similar proportion (2.5- to 5.0-fold) in all mice but did not affect duodenal nonheme iron levels. Low iron diet feeding raised iron absorption but reduced duodenal and liver nonheme iron levels. In a second experiment, mice fed nonpurified diet were divided into four groups and exposed to normal atmosphere or hypoxia (53.3 kPa) with or without dosing with 100 µg iron by stomach tube 1 h before determining iron absorption. There was no effect of iron dosing on iron absorption at either pressure. The data suggest that the control of iron absorption by tissue oxygen acts through a mechanism independent of the control exerted by dietary or mucosal iron levels.

Quantitative results for the direct participation of the parenchymal vascular system in cerebral waste removal

Background: Impaired cerebral waste clearance (CWC) has been associated with a broad range of both physiological and pathophysiological neurologic conditions.1,2 Because of the unique anatomy of the brain parenchyma, theoretically, in the brain parenchyma, biochemically inert waste such as magnetic resonance imaging (MRI) contrast agents can only be removed through two possible pathways: cerebrospinal fluid (CSF) pathway, and/or vascular pathway. Despite the controversy, there seems to be a solid consensus on the participation of the CSF pathway in CWC.3 In contrast to the CSF system, the current consensus is that the parenchymal vascular system does not participate in CWC. Considering there is a big difference in flow rate between the blood (2 mL/min) and the CSF (3.7 µL/min) and the brain is the most bioactive, energy-consuming organ (20% nutrition for about 5% of body weight) in the body, it is illogical that the brain would rely on the slow CSF circulation for CWC while less bioactive tissues outside the brain require both the fast vascular and slow lymphatic systems to remove waste in a timely manner.4,5&#x0D; Methods: Superparamagnetic iron oxide–enhanced susceptibility-weighted imaging (SPIO-SWI) and quantitative susceptibility mapping (QSM) methods were used to simultaneously study 7 T MRI signal changes in parenchymal veins, arteries, and their corresponding para-vascular spaces in 26 rats, following intra-cisterna magna (ICM) infusion of different CSF tracers (FeREX, ferumoxytol, Fe-Dextran) to determine the amount of tracer in the artery and vein quantitatively.&#x0D; Results: The parenchymal venous system participated in CSF tracer clearance following ICM infusion of different MRI tracers with different concentrations of iron. Parenchymal venous participation was more obvious when 75 μg iron was injected. In the parenchymal veins, the relative mean (±SE) value of the susceptibility increased by 13.5±1.0% at 15 min post-tracer infusion (p&lt;0.01), and 33.6±6.7% at 45 min post-tracer infusion (p=0.01), compared to baseline. In contrast to the parenchymal veins, a negligible amount of CSF tracer entered the parenchymal arteries: 1.3±2.6% at 15 min post-tracer infusion (p=0.6), and 12±19% at 45 min post-tracer infusion (p=0.5), compared to baseline.&#x0D; Conclusions: MRI tracers can enter the parenchymal vascular system and more MRI tracers were observed in the cerebral venous than arterial vessels, suggesting the direct participation of parenchymal vascular system in CWC.

Determination of Heavy Metal Remediation to Soil from Community Buildings’ Rooftop

Considering the importance of water in the world, the amount of usable water is not sufficient throughout the world, the existing available fresh water resources are not enough, therefore, water shortages may be encountered in the following years. Keeping the quality of water as it is demanded gains more importance than before. Particularly, heavy metals begin to interfere with groundwater resources, and the quantity of pollution growing due to industrialization, and urbanization. In the present study, the quantitative analysis of heavy metals in harvested rainwater from the rooftop of public buildings in Bornova, Izmir is investigated. The results show that a minimum of 5 μg of copper, 4 μg of zinc, 2.69 μg of lead, 0.095 μg of cadmium, 0.55 μg of chromium, 89,7 μg of iron, 0.96 μg of arsenic, 0.0119 μg of mercury and 3.88 μg of nickel should be tossed away for obtaining a liter of potable water. In conclusion, first flush diverters are recommended to convert these non-point pollutants to point source. Thus, municipalities can take necessary measures to protect the environment such as using phytoremediation and hyperaccumulator plants in sewages.

The role of the parenchymal vascular system in cerebrospinal fluid tracer clearance.

The current understanding of cerebral waste clearance (CWC) involves cerebrospinal fluid (CSF) participation but lacks convincing evidence for the direct participation of the parenchymal vascular system. The objective of this study was to evaluate the role of the parenchymal vascular system in CSF tracer clearance in rats. We used superparamagnetic iron oxide-enhanced susceptibility-weighted imaging (SPIO-SWI) and quantitative susceptibility mapping (QSM) methods to simultaneously study 7 T MRI signal changes in parenchymal veins, arteries, and their corresponding para-vascular spaces in 26 rats, following intra-cisterna magna (ICM) infusion of different CSF tracers (FeREX, Ferumoxytol, Fe-Dextran) to determine the amount of tracer in the artery and vein quantitatively. We observed that the parenchymal venous system participated in CSF tracer clearance following ICM infusion of different MRI tracers with different concentrations of iron. Parenchymal venous participation was more obvious when 75 μg iron was injected. In the parenchymal veins, the relative mean (± SE) value of the susceptibility increased by 13.5 (± 1.0)% at 15 min post-tracer infusion (p < 0.01), and 33.6 (± 6.7)% at 45 min post-tracer infusion (p = 0.01), compared to baseline. In contrast to the parenchymal veins, a negligible amount of CSF tracer entered the parenchymal arteries: 1.3 (± 2.6)% at 15 min post-tracer infusion (p = 0.6), and 12 (± 19)% at 45 min post-tracer infusion (p = 0.5), compared to baseline. MRI tracers can enter the parenchymal vascular system and more MRI tracers were observed in the cerebral venous than arterial vessels, suggesting the direct participation of parenchymal vascular system in CWC. • MRI results revealed that the parenchymal venous system directly participates in cerebrospinal fluid tracer clearance following ICM infusion of MRI tracer. • Different sizes of MRI tracers can enter the parenchymal venous system.

A Comprehensive Grading System for a Magnetic Sentinel Lymph Node Biopsy Procedure in Head and Neck Cancer Patients.

Simple SummaryWith 30% of clinically negative early-stage oral cancer patients harboring occult metastasis, an accurate staging of metastatic lymph nodes (LN) is of utmost importance for treatment planning. A magnetic sentinel lymph node biopsy (SLNB) procedure is offered as an alternative to conventional SLNB in oral oncology, however, a grading system is missing. A proper grading system is preferred to connect the different components of the magnetic SLNB: preoperative imaging, intraoperative detection, and histopathological examination of sentinel lymph nodes (SLNs). This study aims to provide a first grading system based on the distribution of a magnetic tracer, by means of preoperative magnetic resonance imaging (MRI), intraoperative estimation of iron content, and histopathological assessment of resected nodes. Pre- and post-operative MRI and harvested SLNs of eight tongue cancer patients with successful magnetic SLNB procedure were used for analyses.A magnetic sentinel lymph node biopsy ((SLN)B) procedure has recently been shown feasible in oral cancer patients. However, a grading system is absent for proper identification and classification, and thus for clinical reporting. Based on data from eight complete magnetic SLNB procedures, we propose a provisional grading system. This grading system includes: (1) a qualitative five-point grading scale for MRI evaluation to describe iron uptake by LNs; (2) an ex vivo count of resected SLN with a magnetic probe to quantify iron amount; and (3) a qualitative five-point grading scale for histopathologic examination of excised magnetic SLNs. Most SLNs with iron uptake were identified and detected in level II. In this level, most variance in grading was seen for MRI and histopathology; MRI and medullar sinus were especially highly graded, and cortical sinus was mainly low graded. On average 82 ± 58 µg iron accumulated in harvested SLNs, and there were no significant differences in injected tracer dose (22.4 mg or 11.2 mg iron). In conclusion, a first step was taken in defining a comprehensive grading system to gain more insight into the lymphatic draining system during a magnetic SLNB procedure.

Laparoscopic Probe for Sentinel Lymph Node Harvesting Using Magnetic Nanoparticles.

Sentinel lymph node harvesting is an essential step in the surgical treatment of a growing number of malignancies. Various techniques are available to facilitate this purpose. The present study reports a new laparoscopic technique for lymph node harvesting using magnetic nanoparticles containing a superparamagnetic iron-oxide core and dextran coating. This study assesses the clinical relevance of the prototype and provides input for further technological development on the way to clinical implementation. A laparoscopic differential magnetometer prototype was built, utilizing a nonlinear detection principle (differential magnetometry) for magnetic identification of lymph nodes. The iron content sensitivity, depth & spatial sensitivity, and angular sensitivity were analyzed to investigate clinical options. The minimum detectable amount of iron was 9.8 μg at a distance of 1 mm. The detection depth was 5, 8, and 10 mm for samples containing 126, 252, and 504 μg iron, respectively. The maximum lateral detection distance was 5, 7, and 8 mm for samples containing 126, 252, and 504 μg iron, respectively. A sample containing 504 μg iron was detectable at all angulations assessed (0°, 30°, 60° and 90°). The laparoscopic differential magnetometer demonstrates promising results for further investigation and development towards laparoscopic lymph node harvesting using magnetic nanoparticles. The laparoscopic differential magnetometer facilitates a novel method for sentinel lymph node harvesting, which helps to determine prognosis and treatment of cancer patients.

Analysis of toxicity of iron oxide nanocomposite encapsulated in a polymer matrix of arabinogalactan

Introduction. The article presents a toxicity analysis of the Fe3O4 nanocomposite encapsulated in the natural polymer matrix of arabinogalactan (AG). A study was devoted to forming and developing the biological response of organisms to subacute administration of this nanocomposite. Materials and methods. White outbred male rats weighing 200-220 gr. were used in this study. For ten days, a test drug solution was administered orally to animals with a probe at a dose of 500 μg of iron per kilogram of body weight. Then, using histological and immunohistochemical analysis methods, the severity of the biological response of the organism to the introduction of this nanocomposite was evaluated. An analysis was made of the state of tissue of the liver, kidneys, and sensorimotor cortex. The number of neurons with the proapoptotic caspase three protein expression, anti-apoptotic bcl-2 protein, and HSP 70 stress protein was determined in the sensorimotor cortex tissue. Results. With intragastric administration to experimental animals, there was a violation of normal blood rheology in liver and kidney tissue, protein dystrophy of hepatocytes, expansion of perivascular spaces of brain tissue, and a decrease in the total number of sensorimotor cortex neurons per unit area. Immunohistochemical analysis of tissue of the sensorimotor cortex for expression of pro-and anti-apoptotic proteins and the expression of HSP 70 protein showed a sharp increase in the number of neurons with the expression of HSP 70 stress protein. Discussion. The nature of the detected changes indicates the occurrence of compensatory-adaptive reactions in the organism in response to the effect of FeAG. The lack of expression of caspase 3 protein eliminates the development of apoptosis.

Abstract 1138: Non-invasive detection and quantification of tumor-associated macrophage density with magnetic particle imaging

Abstract Background: There is increasing interest in the role of tumor-associated macrophages (TAMs) in promoting cancer growth and metastatic potential.(Obeid 2013) Increased TAM density has been correlated with poor prognosis and they can contribute up to 50% of the mass in breast tumors.(Bingle 2002) Previous studies have used cellular MRI to indirectly image the spatial distribution of TAMs, through the in situ uptake of superparamagnetic iron oxide (SPIO) nanoparticles (Makela 2017). However, iron-based MRI is limited by low specificity and challenging quantification. Magnetic Particle Imaging (MPI) is an emerging cellular imaging technique that can directly detect and quantify SPIO in vivo (Zheng 2016). MPI produces a positive contrast signal that is not attenuated by biological tissue. In this study, we investigated the first application of MRI and MPI to detect and differentiate between murine breast cancer models with varying metastatic potentials. Methods: Female BALB/c mice were implanted with 300,000 4T1 (n=3) or 168FARN (n=3) into the inguinal mammary fat pad. Tumors were grown for 3 weeks. 24 hours prior to imaging, 100μL of ferucarbotran (Magnetic Insight) was administered IV. One mouse from each group was first imaged on a 3T clinical MRI (GE Healthcare) with a custom-gradient insert located at Robarts Research Institute. A balanced steady-state free precession pulse sequence was used with imaging time of 30mins. The mice were then sacrificed and fixed in formalin. MPI was performed at Stanford University with the MPI system (Magnetic Insight) alongside three reference fiducials of known concentration. Iron quantification was performed with VivoQuant (inviCRO). Tumor tissue was extracted for histology and ex vivo imaging. Results: MRI signal voids were observed throughout the 4T1 tumor, but predominately in the tumor periphery. Fewer voids were observed in the 168FARN model, consistent with previous studies.3 MPI signal was observed in two out of three 4T1 tumors. Signal is seen across the entire tumor since the MPI is a sagittal projection compared to a single MRI slice. MPI quantification of SPIO in the 4T1 tumors indicated a consistent uptake, of 4.7 and 5.9 μg of iron. Signal was also detectable in the liver and tail at the site of injection. Fewer voids were observed in the 168FARN model, consistent with previous studies (Makela 2017). MPI signal was not detected in the tumors of the 168FARN group, consistent with the low iron uptake observed in the MRI. Histological analysis will be performed to verify the SPIO and macrophage distribution in tumor samples. Conclusions: By combining the high spatial resolution of MRI with the accurate quantification and specificity of MPI, additional information can be obtained on TAM presence and distribution. In addition to aiding therapeutic development, this information could be utilized to more accurately grade cancer. Citation Format: Jeffrey M. Gaudet, Ashley V. Makela, Paula J. Foster. Non-invasive detection and quantification of tumor-associated macrophage density with magnetic particle imaging [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 1138.

Development of device for quantifying magnetic nanoparticle tracers accumulating in sentinel lymph nodes

The developed device with electromagnetic coils and small permanent magnets quantifies the iron contents of superparamagnetic iron oxide nanoparticles for sentinel lymph node (SLN) biopsy. To remove diamagnetic and paramagnetic components and detect only superparamagnetic components, a 2nd harmonics signal is detected by a gradiometer under a moderate AC magnetic field (1–2 mT) with the fundamental frequency (2.944 kHz) of the coils and DC magnetic field (1–2 mT) of the magnets. The detection limit with a signal-to-noise ratio of 5 is approximately 0.28 μg of iron, and the device has a wide dynamic range of 104, 0.28 μg–2.8 mg. Additional coils and permanent magnets play an important role producing the optimum distribution of AC/DC magnetic fields for an iron distribution-independent and SLN size-independent quantification. We demonstrated the quantification of the iron in phantoms, which have a size of 3–20 mm with varied iron distributions and contain magnetic nanoparticles numerically. These results indicate that the developed device is useful for quantifying the magnetic nanoparticles accumulating in SLNs.

Adsorption-photometric determination of iron using silica with nitroso-R salt and nitroso-N salt functional groups

Adsorbents based on silica sequentially modified by polyhexamethylene guanidine and nitroso-R salt or nitroso-N salt are proposed for the preconcentration and adsorption-photometric determination of iron. It is shown that these adsorbents quantitatively recovered Fe(III) at pH 3.5–4.0 and Fe(II) at pH 4.5–7.0. In the adsorption of Fe(III) and Fe(II), intensely colored green complexes formed on the adsorbent surface. Based on the absence of signals in EPR spectra, it was concluded that iron in the oxidation state +2 was included into surface complexes with nitroso-R salt or nitroso-N salt. When Fe(III) interacted with nitroso-R salt or nitroso-N salt immobilized on the adsorbent surface, it was reduced to Fe(II). Diffuse reflection spectra of the surface complexes of iron(II) were broad bands with maxima at 720 and 710 nm. Procedures of the adsorption-photometric determination of iron in natural waters and snow samples were developed with the limit of detection of 0.05 μg of iron per 0.2 g of the adsorbent.

The In-Vivo Use of Superparamagnetic Iron Oxide Nanoparticles to Detect Inflammation Elicits a Cytokine Response but Does Not Aggravate Experimental Arthritis

BackgroundSuperparamagnetic Iron Oxide Nanoparticles (SPION) are used in diagnostic imaging of a variety of different diseases. For such in-vivo application, an additional coating with a polymer, for example polyvinyl alcohol (PVA), is needed to stabilize the SPION and prevent aggregation. As the particles are foreign to the body, reaction against the SPION could occur. In this study we investigated the effects that SPION may have on experimental arthritis after intra-articular (i.a.) or intravenous (i.v.) injection.MethodsPVA-coated SPION were injected either i.a. (6 or 24 μg iron) or i.v. (100 μg or 1 mg iron) into naïve Toll-like receptor-4 deficient (TLR4-/-) or wild-type C57Bl/6 mice, or C57Bl/6 mice with antigen-induced arthritis. As control, some mice were injected with PVA or PBS. MR imaging was performed at 1 and 7 days after injection. Mice were sacrificed 2 hours and 1, 2, 7, 10 and 14 days after injection of the SPION, and RNA from synovium and liver was isolated for pro-inflammatory gene expression analysis. Serum cytokine measurements and whole knee joint histology were also performed.ResultsInjection of a high dose of SPION or PVA into naïve knee joints resulted in an immediate upregulation of pro-inflammatory gene expression in the synovium. A similar gene expression profile was observed after SPION or PVA injection into knee joints of TLR4-/- mice, indicating that this effect is not due to LPS contamination. Histological analysis of the knee joints also revealed synovial inflammation after SPION injection. Two hours after i.v. injection of SPION or PVA into naïve mice, an upregulation of pro-inflammatory gene expression was detected in the liver. Administration of SPION or PVA into arthritic mice via i.a. injection did not result in an upregulation in gene expression and also no additional effects were observed on histology. MR imaging and histology showed long-term retention of SPION in the inflamed joint. However, 14 days after the injections no long-term effects were evident for gene expression, histology or serum cytokine concentrations.ConclusionsInjection of SPION, either locally or systemically, gives an acute inflammatory response. In the long term, up to 14 days after the injection, while the SPION reside in the joint, no further activating effects of SPION were observed. Hence, we conclude that SPION do not aggravate arthritis and can therefore be used safely to detect joint inflammation by MR imaging.

Depth limitations for in vivo magnetic nanoparticle detection with a compact handheld device

Abstract The increasing interest for local detection of magnetic nanoparticles (MNPs) during clinical interventions requires the development of suitable probes that unambiguously detect the MNPs at a depth of several centimeters in the body. The present study quantitatively evaluates the limitations of a conventional magnetometry method using a sinusoidal alternating field. This method is limited by the variability of the magnetic susceptibility of the surrounding diamagnetic tissue. Two different sensors are evaluated in a theoretical model of MNP detection in a tissue volume. For a coil that completely encloses the sample volume, the MNPs can be detected if the total mass contributing to the signal is larger than 4.1 × 10 − 7 times the tissue mass. For a handheld surface coil, intended to search for the MNPs in a larger tissue volume, an amount of 1 μg of iron oxide cannot be detected by sensors with a diameter larger than 15 mm. To detect a spot with MNPs at 5 cm depth in tissue, it should contain at least 325 μg iron oxide. Therefore, for high-sensitive clinical MNP detection in surgical interventions, techniques with increased specificity for the nonlinear magnetic properties of MNPs are indispensable.

Marginally excessive iron loading transiently blocks mucosal iron uptake in iron-deficient rats

Regular "mucosal block" is characterized by decreased uptake of a normal iron load 3-72 h after the administration of excess iron (generally 10 mg) to iron-deficient animals. We found that short-acting mucosal block could be induced by much lower iron concentration and much shorter induction time than previously reported, without affecting levels of gene expression. A rapid endocytic mechanism was reported to decrease intestinal iron absorption after a high iron load, but the activating iron load and the time to decreased absorption were undetermined. We assessed the effects of 30-2,000 μg iron load on iron uptake in the duodenal loop of iron-deficient and iron-sufficient rats under anesthesia. One hour later, mucosal cellular iron uptake in iron-deficient rats administered 30 μg iron was 76.1%, decreasing 25% to 50.7% in rats administered 2,000 μg iron. In contrast, iron uptake by iron-sufficient rats was 63% (range 60.3-65.5%) regardless of iron load. Duodenal mucosal iron concentration was significantly lower in iron-deficient than in iron-sufficient rats. Iron levels in portal blood were consistently higher in iron-deficient rats regardless of iron load, in contrast to the decreased iron uptake on the luminal side. Iron loading blocked mucosal uptake of marginally excess iron (1,000 μg), with a greater effect at 15 min than at 30 min. The rapid induction of short-acting mucosal block only in iron-deficient rats suggests DMT1 internalization.

Determinação de ferro (III) em produtos farmacêuticos por titulação fotométrica

This paper describes a simple, precise and low-cost photometric titration method for iron (III) determination in pharmaceutical preparations. The photometric titration system was constructed using the peristaltic pump of a conventional spectrophotometer. The method is based on titration of iron (III) with EDTA using salicylic acid as indicator. The absorption of the iron (III)-salicylic acid complex was monitored spectrophotometrically at 525 nm. The limit of quantification was 5 µg of iron (III). The photometric titration procedure was applied for the determination of iron (III) in samples of ferrous sulfate and ferric hydroxide polymaltose complex. The procedure showed sensibility, reproducibility and accuracy for use as a method for the routine analysis of iron (III) in pharmaceutical formulations.

Effects of the pyrones, maltol and ethyl maltol, on iron absorption from the rat small intestine

The pyrones, 3-hydroxy-2-methyl-4-pyrone (maltol) and 3-hydroxy-2-ethyl-4-pyrone (ethyl maltol) chelate iron with a high affinity and selectivity. The resulting 1:3 (metal-ligand) complexes, being neutral, are able to partition readily across cell membranes and thus may facilitate iron transport across the intestinal wall. Absorption of radioactive iron (59Fe) in the presence of these pyrones was investigated in male rats 1, 2, 4 and 6 h after intraduodenal administration of a 7 micrograms dose and compared with that of 59Fe given as the sulphate, gluconate, fumarate or complexed to EDTA. Total body absorption and distribution were calculated from the 59Fe content of various tissue samples. With all the iron preparations used, blood levels of 59Fe were highest 1 h after injection whilst the 59Fe content at the major site of deposition, i.e. the bone marrow, increased up to 6 h. No 59Fe was found in the urine. Total body absorption of 59Fe was significantly higher from the pyrones than from the other four preparations. Over the dose range 0.7-700 micrograms, the proportion of 59Fe absorbed from both iron maltol and iron sulphate decreased with increasing dose. Enhanced 59Fe uptake from maltol was evident at 0.7-70 micrograms but not at 700 micrograms suggesting that use of these pyrones will not result in iron overload. Absorption of 59Fe given into the stomach was slower in onset but was sustained longer presumably via a steady delivery of iron to the duodenum from the gastric reservoir.(ABSTRACT TRUNCATED AT 250 WORDS)

Determination of Total Iron in Environmental Samples by Solid Phase Extraction with Dimethyl(E)‐2‐(2‐Methoxyphenoxy)‐2‐Butenedioate

AbstractA novel solid phase extraction technique for determination of total iron in environmental water samples was developed. The method is based on sorption of Fe(III) ions on octadecyl silica membrane disk modified with a new synthetic ligand dimethyl(E)‐2‐(2‐methoxyphenoxy)‐2‐butenedioate (I). Iron(III) is quantitatively retained on the disk in the pH range of 3–7 at a flow rate of 1–7 mL min−1. The Fe(III) eluted with 10 mL of 0.01 M EDTA and than was measured by flame atomic absorption spectrometry (FAAS) at 248.3 nm. The maximum capacity disk modified by 7 mg of ligand was found to be 197 ± 2 μg of iron(III). The breakthrough volume was greater than 2000 mL. The iron(III) was completely recovered (&gt; 99%) from water with a preconcentration factor of more than 200. The limit of detection of the proposed method was 1.00 ng mL−1. The various cationic and anionic interferences had no effect on the recovery of iron(III) from the binary mixtures. The proposed method was successfully applied to determination of total iron from three different water samples.

Effects of Intracerebroventricular Injection of Iron Dextran on the Iron Concentration and Divalent Metal Transporter 1 Expression in the Caudate Putamen and Substantia Nigra of Rats

The cellular localization of DMT1 and its functional characterization suggest that DMT1 may play an important role in the physiological brain iron transport. But the regulation of DMT1 expression by iron in the brain is still not clearly understood. In this study, both the contents of ferric and ferrous iron as well as DMT1 expression were evaluated in CPu and SN after ICV of 500 microg iron dextran/rat/day for 3 or 7 days. It was found that the iron levels in CPu and SN were not altered obviously until ICV for 7 days. Immunohistochemistry results indicated that the expression of DMT1 (-IRE) in CPu and SN was not altered significantly after 3 days of ICV. Whereas the expression of DMT1 (-IRE) decreased significantly after 7 days of ICV when ferrous iron was increased significantly. Contrary to that of DMT1 (-IRE) in the same regions, there were no significant alterations in DMT1 (+IRE) expression in CPu and SN in spite of the existence of the altered iron levels, compared with that of control groups. The results demonstrate that DMT1 (-IRE) expression was correlated probably with brain iron levels; especially, its regulation was correlated with ferrous iron (not ferric iron) in CPu and SN in adult rats, compared with those of saline-injected control rats. The effect of ferrous iron on the expression of DMT1 (-IRE) in the brain also suggests that it might play a major physiological role in brain iron uptake and transport, but further studies are needed to clarify these issues.

Solid phase extraction and flame atomic absorption spectroscopic determination of trace amounts of iron(III) using octadecyl silica membrane disks modified with 2-mercaptopyridine-1-oxide

A simple and selective method for rapid extraction and determination of trace amounts of iron(III) using octadecyl-bonded silica membrane disks modified with 2-mercaptopyridine-1-oxide and flame atomic absorption spectroscopy is presented. The factors influencing extraction efficiency were evaluated, including the nature of the counter anion, pH of the sample solution, amount of ligand, flow rate of the sample and type of stripping solution. The maximum capacity of the membrane disk, modified by 10 mg of the ligand, was found to be 926 ± 6 μg of iron(III). The breakthrough volume was greater than 2500 ml. Iron(III) was completely recovered (>99%) from water with a preconcentration factor of more than 166. The limit of detection of the proposed method was 0.63 ng ml−1. The various cationic interferences had no effect on the recovery of iron(III) from the binary mixtures. The proposed method was applied to the determination of iron(III) from three different water samples.

Development of an MRI/x-ray/ultrasound compatible marker for pre-operative breast tumour localization

This paper describes an in vitro investigation into the composition, structure and development of an magnetic resonance imaging (MRI), ultrasound (US) and x-ray imaging compatible marker for breast tumour localization. The marker is composed of 0.4–0.6 mm glass and iron-containing aluminium microspheres suspended in a gelatin matrix. The final form of the marker is a cylindrical shape 7 mm long with 2.05 mm diameter to facilitate delivery through a 12 gauge biopsy needle. To get optimal reflectivity for the US contrast, the glass microsphere concentration was found to be 40% by weight. US contrast is independent of marker orientation and the cylindrical shape made its US signal appearance distinctive thus ensuring confident identification. To control the MRI contrast, iron content was varied to generate a clear and local susceptibility signal void to reflect the marker position. Optimal iron content was found to be 52 µg iron which produced a clear signal void in spoiled gradient recalled MR images. The appearance of the susceptibility artefact is determined by the marker's shape, orientation and echo time. The final marker produces a dark artefact in MRI while appears as a clear hyperintense structure with acoustic shadowing in US images. The x-ray image showed the marker as a radio-opaque structure. This in vitro study demonstrates that the marker forms an alternative to traditional wire localization currently used for breast surgical procedures and creates new opportunities for US guided surgical procedures.

Migration of inorganic contaminants into dry food from packaging made from recycled paper and board

A radiotracer method was applied to the measurement of inorganic contaminants migrating into food. The method was applied to the study of 10 samples of recycled paper and board. The only elements detected in the static migration test were zinc and iron, at concentrations close to the detection limit. Samples of rice, oats, custard powder, mushrooms and fries showed that traces of these elements had migrated from the packaging. The migration was limited to less than 1%, with the exception of the mushrooms, where the decomposition of the food had resulted in a 12.5% transfer of zinc from the mushroom bag after 8 days, equivalent to migration of 0.022 mg dm−2. Shaking had no effect on migration, except in one case of custard powder where migration occurred at a level equivalent to 0.002 mg dm−2. The maximum migration determined in the present study was 4.8 µg zinc and 2.6 µg iron, which is negligible when compared with the recommended daily intakes of 15 and 14 mg, respectively. When Tenax was tested as a food simulant, no zinc was detected (<0.001 mg dm−2), although slight migration (0.001 mg dm–2) occurred into food.