Iron Behaving Badly: Inappropriate Iron Chelation as a Major Contributor to the Aetiology of Vascular and Other Progressive Inflammatory and Degenerative Diseases

The production of peroxide and superoxide is an inevitable consequence of aerobic metabolism, and while these particular "reactive oxygen species" (ROSs) can exhibit a number of biological effects, they are not of themselves excessively reactive and thus they are not especially damaging at physiological concentrations. However, their reactions with poorly liganded iron species can lead to the catalytic production of the very reactive and dangerous hydroxyl radical, which is exceptionally damaging, and a major cause of chronic inflammation. We review the considerable and wide-ranging evidence for the involvement of this combination of (su)peroxide and poorly liganded iron in a large number of physiological and indeed pathological processes and inflammatory disorders, especially those involving the progressive degradation of cellular and organismal performance. These diseases share a great many similarities and thus might be considered to have a common cause (i.e. iron-catalysed free radical and especially hydroxyl radical generation). The studies reviewed include those focused on a series of cardiovascular, metabolic and neurological diseases, where iron can be found at the sites of plaques and lesions, as well as studies showing the significance of iron to aging and longevity. The effective chelation of iron by natural or synthetic ligands is thus of major physiological (and potentially therapeutic) importance. As systems properties, we need to recognise that physiological observables have multiple molecular causes, and studying them in isolation leads to inconsistent patterns of apparent causality when it is the simultaneous combination of multiple factors that is responsible. This explains, for instance, the decidedly mixed effects of antioxidants that have been observed, etc...Comment: 159 pages, including 9 Figs and 2184 reference

A pulse radiolysis study of free radicals formed by one-electron oxidation of the antimalarial drug pyronaridine

Free radicals from one-electron oxidation of the antimalarial drug pyronaridine have been studied by pulse radiolysis. The results show that pyronaridine is readily oxidised to an intermediate semi-iminoquine radical by inorganic and organic free radicals, including those derived from tryptophan and acetaminophen. The pyronaridine radical is rapidly reduced by both ascorbate and caffeic acid. The results indicate that the one-electron reduction potential of the pyronaridine radical at neutral pH lies between those of acetaminophen (707 mV) and caffeic acid (534 mV). The pyronaridine radical decays to produce the iminoquinone, detected by electrospray mass spectrometry, in a second-order process that density functional theory (DFT) calculations (UB3LYP/6-31+G*) suggest is a disproportionation reaction. Important calculated dimensions of pyronaridine, its phenoxyl and aminyl radical, as well as the iminoquinone, are presented

Controlling wettability of the each side of the PLA fabric through orientation of the working gases (O2 and CH4) during cold plasma treatment

This study aimed to obtain a bifunctional fabric from the point of view of hydrophilicity/hydrophobicity for biomedical applications. To achieve this, both sides of a fabric of polylactic acid (PLA) were subjected to a plasma treatment. While in a side the oxygen was introduced to the other side, simultaneously, was added methane. The plasma treatment was performed at 100 W, 1.8 mbar, during 30 minutes. By Scanning Electron Microscopy (SEM) morphological analysis, it became evident that the fabric side facing the oxygen inlet showed micropittings, while the reverse side had smooth surfaces. Analysis by X-Ray photoelectron spectroscopy (XPS) revealed an increase in the amount of oxygen in the surface of the PLA on both sides of the fabric. The surface function was characterized by measurements of water absorption rate, where it was determined that one fabric side was more hydrophilic than the other side. The results indicated achievement of a bifunctional fabric through orientation of working gases during a plasma treatment.The authors are acknowledging to financial support supplied by CAPES - Brasília/Brazil through of the CAPES/IGC program - CGCI n° 055/2010