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Electrochemical Fabrication of Carbon Nanomaterial and Conducting Polymer Composites for Chemical Sensing
Published in Di Wei, Electrochemical Nanofabrication, 2017
Zhanna A. Boeva, Rose-Marie Latonen, Tom Lindfors, Zekra Mousavi
AA has an important role in the biosynthesis of e.g. collagen and neurotransmitters, iron metabolism and immune system. Also for the AA detection, the electrochemical biosensors offers simplicity, high selectivity and sensitivity compared to conventional methods of analysis. This has been utilized in the electrochemical biosensor based on PEDOT-RGO composite with AO immobilized in it [90] resulting in a nanocomposite with high surface area and conductivity, good biocompatibility and fast redox properties. The electrode based on PEDOT-RGO composite film was fabricated by electropolymerization from an aqueous solution consisting of GO, EDOT, LiClO4, and AO. In this case, the negatively charged GO sheets, the anions and the AO were simultaneously incorporated in the polymer matrix as charge compensating counter ions during the polymerization process. The advantage of the fabrication method utilizing CV is that it promotes both the PEDOT-GO film growth at more positive potentials and also the electrochemical reduction of GO to RGO in the negative potential regime. Therefore, the PEDOT-RGO biosensor film can elegantly be formed in one-step. AA detection, which was carried out at 0.4 V, had a linear response range of 5μ480 μM and a LOD of 2 × 10−6 M. The sensor had a short response time and much higher sensitivity for the AA oxidation than the PEDOT-AO film.
Targeted Magnetic Resonance Imaging of Angiogenesis in the Vascular System
Published in Robert J. Gropler, David K. Glover, Albert J. Sinusas, Heinrich Taegtmeyer, Cardiovascular Molecular Imaging, 2007
Ebo D. de Muinck, Justin D. Pearlman
As outlined previously, the choice is between agents that enhance MR contrast, i.e., paramagnetic T1 agents based on Gd that “brighten” the MR image, and agents that have a negative contrast effect, superparamagnetic T2 agents based on iron that darken the image. The effect of a single gadolinium atom on longitudinal relaxation is far less pronounced than the effect of one iron atom on transverse relaxation, and detectable concentrations of Gd in vivo are in the millimolar range, whereas iron atoms can be detected at nanomolar levels in vivo (21). Because of their greater relaxivity, superparamagnetic metals exert effects well beyond their size, and this means that these agents create an extensive imaging void that may obscure structural aspects such as micro-vessel architecture of surrounding tissue (62). Because T1 agents do not obscure their surroundings, they allow for an imaging strategy that could identify a region of interest at low resolution, which could then be examined in more detail at high resolution. The low relaxivity thus may constitute an advantage if surrounding tissue is to be imaged. A disadvantage of Gd is that it is not biocompatible and therefore needs to be administered in the form of chelates such as Gd-DTPA. Little is know about the potential toxicity following cellular dechelation after the agents have reached the cytoplasm. Iron based agents on the other hand are composed of biodegradable iron, which is biocompatible and can be processed using normal cellular pathways for iron metabolism.
The association of lung cancer and asbestosis
Published in Dorsett D. Smith, The Health Effects of Asbestos, 2015
Chrysotile asbestos contains relatively little iron, approximately 2%–3% in the average sample, whereas crocidolite asbestos, which is generally considered the most carcinogenic form of asbestos, has up to 36% iron by weight. It has been reported that individuals that consume excessive amounts of iron have an increased risk of cancer. Iron appears to be toxic and when asbestos fibers are phagocytized there may be abnormal release of iron not controlled by the proteins involved in normal iron metabolism. Asbestos-related pulmonary toxicity appears to be initiated by reactive oxygen species generated from mobilized iron via the Haber–Weiss reaction, as mentioned above. Epidermal growth factor is a trans-membrane protein that is involved in cell injury from both inhibition of apoptosis and increased cell proliferation. The administration of the antioxidant enzyme catalase to rats during inhalation of asbestos fibers can ameliorate inflammation, lung damage, and pulmonary fibrosis or asbestosis in part related to inactivation of epidermal growth factor. It seems plausible that asbestos fiber iron content relates to its carcinogenicity. In fact, the evidence that asbestos-related cytotoxicity is inhibited by anti-toxin enzymes and iron chelation by desferrioxamine, indicates a strong biological contribution of active oxygen species, and the secondary role of iron content in asbestos fibers in its toxic effects, which may have future clinical implications. (Baldys A, Aust A. Role of iron in inactivation of epidermal growth factor after asbestos treatment of human lung and pleural target cells. Am J Respir Cell Mol Biol 2005;32:436–42.)
Dietary supplements for consideration in elite female footballers
Published in European Journal of Sport Science, 2022
Hannah C. Sheridan, Lloyd J. F. Parker, Kelly M. Hammond
Iron cannot be endogenously synthesised; therefore, adequate iron intake and absorption are key to maintain optimal levels. Maintaining iron stores through diet alone can pose a significant challenge due to low bioavailability of haem (15–35%) and non-haem (2–20%) dietary iron, dietary restrictions (vegetarian/vegan), low energy intake, lack of knowledge and the post-exercise hepcidin response. In the hours (3–6 h) following exercise, hepcidin levels increase 2–7-fold and absorption of dietary iron is suppressed during this window (McCormick, Sim, Dawson, & Peeling, 2020). Findings have shown that morning hepcidin levels and those immediately after exercise (within 30 min) are significantly lower, thus providing an effective period for consumption of iron-rich foods or supplements (McCormick et al., 2020). In addition, the female hormone oestrogen can influence iron metabolism via the suppressive effects on hepcidin, which when elevated, further reduces the absorption of dietary iron (Hou et al., 2012). To the author’s knowledge, there is currently no research specifically looking at the effects of the primary female hormones’ oestrogen and progesterone (and their synthetic form oestradiol and progestogens) in elite female football players.
Pleural mesothelioma and lung cancer: the role of asbestos exposure and genetic variants in selected iron metabolism and inflammation genes
Published in Journal of Toxicology and Environmental Health, Part A, 2019
F. Celsi, S. Crovella, R. R. Moura, M. Schneider, F. Vita, L. Finotto, G. Zabucchi, P. Zacchi, V. Borelli
Inflammation and disruption of Fe homeostasis are hallmarks of asbestos exposure affecting specifically lung tissue and inflammation is a key player in lung cancer development which is mediated by activation of both inflammasome platforms mediated by NLRP1 and NLRP3, expressed and activated in various lung cancer cell lines although at different levels (Kong et al. 2015). However, data demonstrated that, as for MPM, SNPs at NLRP1 and NLRP3 genes appeared not to be involved in LC development. Interestingly, for all tested Fe related-SNPs, similar results were obtained as with mesothelioma samples, suggesting that a common protection mechanism might operate. Iron metabolism is crucial for cells and the whole organism survival, and precise homeostasis of this element is required.
Development of a fluorometric measurement system used in biological samples upon the determination of iron (II) metal ion
Published in Preparative Biochemistry & Biotechnology, 2021
Yavuz Selim Toksöz, İbrahim Ethem Özyiğit, Çiğdem Bilen, Nergis Arsu, Emine Karakuş
Iron metabolism has a critical role at cellular and organismal levels and also has a bioavailability property in immune cells homeostasis and inflammation. Iron is one of the most excessive element in the world and necessary for almost all organisms.[50–52] Iron is used for polymerization processes and metabolic reactions such as oxidation–reduction, hydrolysis, hemoglobin and myoglobin formations and stabilization.[53–55] Soluble iron, which is fundamental for electron transfer and ligands binding reactions, is retained by the active groups of extracellular polymeric substances and proteins.[56–58] It has one of the most widespread and biologically relevant oxidation state as ferrous ion, Fe(II) which is more soluble, bio-active and bioavailable than its ferric Fe(III) form.[50] Moreover, Fe(II) is not only essential cofactor for a number of enzymes involved in neurotransmitter synthesis, including serotonin, norepinephrine, dopamine and DNA synthesis, but also used for gene regulation, binding and transport of oxygen, regulation of cell growth, differentiation in plants and different organisms.[59–61] On the other hand, iron level in biological samples is critically important to cause of the consistence of reactive oxygen species and contributes to diabetic complications.[62] The well-established disorders related to iron metabolism are anemia resulting from iron deficiency and hemochromatosis caused by extreme iron levels.[63] Considering all these factors, it is important to determine trace amounts of Fe(II) in biological samples.