There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality.

Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

I and i

Assay for lipid peroxides in animal tissues by thiobarbituric acid reaction

Lipid peroxidation can be described generally as a process under which oxidants such as free radicals attack lipids containing carbon-carbon double bond(s), especially polyunsaturated fatty acids (PUFAs). Over the last four decades, an extensive body of literature regarding lipid peroxidation has shown its important role in cell biology and human health. Since the early 1970s, the total published research articles on the topic of lipid peroxidation was 98 (1970–1974) and has been increasing at almost 135-fold, by up to 13165 in last 4 years (2010–2013). New discoveries about the involvement in cellular physiology and pathology, as well as the control of lipid peroxidation, continue to emerge every day. Given the enormity of this field, this review focuses on biochemical concepts of lipid peroxidation, production, metabolism, and signaling mechanisms of two main omega-6 fatty acids lipid peroxidation products: malondialdehyde (MDA) and, in particular, 4-hydroxy-2-nonenal (4-HNE), summarizing not only its physiological and protective function as signaling molecule stimulating gene expression and cell survival, but also its cytotoxic role inhibiting gene expression and promoting cell death. Finally, overviews of in vivo mammalian model systems used to study the lipid peroxidation process, and common pathological processes linked to MDA and 4-HNE are shown.

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Lipid peroxidation: production, metabolism, and signaling mechanisms of malondialdehyde and 4-hydroxy-2-nonenal.

Polyphenols are secondary metabolites of plants and are generally involved in defense against ultraviolet radiation or aggression by pathogens. In the last decade, there has been much interest in the potential health benefits of dietary plant polyphenols as antioxidant. Epidemiological studies and associated meta-analyses strongly suggest that long term consumption of diets rich in plant polyphenols offer protection against development of cancers, cardiovascular diseases, diabetes, osteoporosis and neurodegenerative diseases. Here we present knowledge about the biological effects of plant polyphenols in the context of relevance to human health.

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Plant Polyphenols as Dietary Antioxidants in Human Health and Disease

Advances in antithrombotic therapy, along with an early invasive strategy, have reduced the incidence of recurrent ischemic events and death in patients with acute coronary syndromes (ACS; unstable angina, non–ST-segment–elevation myocardial infarction [MI], and ST-segment–elevation MI).1,–,4 However, the combination of multiple pharmacotherapies, including aspirin, platelet P2Y12 inhibitors, heparin plus glycoprotein IIb/IIIa inhibitors, direct thrombin inhibitors, and the increasing use of invasive procedures, has also been associated with an increased risk of bleeding.

Editorial see p 2664

Bleeding complications have been associated with an increased risk of subsequent adverse outcomes, including MI, stroke, stent thrombosis, and death, in patients with ACS and in those undergoing percutaneous coronary intervention (PCI),5,–,10 as well as in the long-term antithrombotic setting.11,12 Thus, balancing the anti-ischemic benefits against the bleeding risk of antithrombotic agents and interventions is of paramount importance in assessing new therapies and in managing patients. Prior randomized trials comparing antithrombotic agents suggest that a reduction in bleeding events is associated with improved survival.13,14

Because prevention of major bleeding may represent an important step in improving outcomes by balancing safety and efficacy in the contemporary treatment of ACS, bleeding events have been systematically identified as a crucial end point for the assessment of the safety of drugs during the course of randomized clinical trials, and are an important aspect of the evaluation of new devices and interventional therapies.15 Unlike ischemic clinical events (eg, cardiac death, MI, stent thrombosis), for which there is now general consensus on end-point definitions,16,17 there is substantial heterogeneity among the many bleeding definitions currently in use. Lack of standardization makes it difficult to optimally organize key clinical trial processes such as adjudication, and even more difficult to interpret relative …

Standardized Bleeding Definitions for Cardiovascular Clinical Trials A Consensus Report From the Bleeding Academic Research Consortium

Effect of Phytochemicals on Diabetes‐Related Neurological Disorders

Present study was conducted to evaluate the effect of oral supplementation of composite extract of leaves (CLE) of four medicinal plants; Aegle marmelos, Ocimum sanctum, Murraya koenigii and Azadirachta indica on markers of oxidative stress in brain tissues of alloxan-induced diabetic rats in vivo. Enhanced lipid peroxidation, protein oxidation and reduced antioxidative defence systems were measured in brain tissues of diabetic rats. Supplementation of CLE, once in a day for 35 days significantly (p < .05) protected the peroxidation of lipid, oxidation of protein and ameliorated the antioxidant defence in brain tissue of diabetic rats. It was observed that the insulin-like effect of CLE was dose dependent; higher effect at higher doses. The results of the study suggest that supplementation CLE may provide an overall homeostasis and significant neuro-protection through rescuing brain cells from oxidative abuse and accelerating brain antioxidative defence during advanced stage of hyperglycaemia.

Effect of oral supplementation of composite leaf extract of medicinal plants on biomarkers of oxidative stress in induced diabetic Wistar rats

Red blood cells have been shown to possess specific insulin receptors, with characteristics similar to the receptors of typical target cells. The present work was carried out to study the modulation of amiloride sensitive Na/H antiport by insulin on rat red blood cells. The activity of the Na/H antiport was determined by a new technique which involves the measurement of the fluorescence of 2',7'-bis(2-carboxyethyl)-5,6-carboxyfluorescein (BCECF) loaded rbc's as function of their intracellular pH (pHi). Our results show that the antiport in red blood cells displays the same behaviour as in other cells and it is inhibited by amiloride. Insulin stimulates the antiport with a dose-dependence similar to other typical insulin effects: a maximum at 10 nM and a smaller effect at higher and lower hormone concentrations. Insulin effect on the antiport was completely abolished by amiloride (0.1 mM) and significantly inhibited by ouabain (1 mM) showing, also in red blood cells, the strict dependence of the Na/H antiport on the functioning of the Na pump.

Insulin modulation of Na/H antiport in rat red blood cells.

Aging, circadian disruption and neurodegeneration: Interesting interplay

Oxidative stress-mediated damage to functional macromolecules followed by their accumulation has been reported as a major factor behind aging and related consequences. Excessive generation of reactive oxygen species and/or depleted cellular defense impairs the balance between prooxidants and antioxidants causing shift in cellular redox state which leads to physiological dysfunctions making the body prone to external deleterious agents. In the present chapter, we have discussed the aging process and have focused on novel markers of oxidative damage that reflect the cellular redox status relevant to age-related studies incorporating the previously well-established markers of the aging process.

Syed Ibrahim Rizvi

Papers

Effect of Phytochemicals on Diabetes‐Related Neurological Disorders

Effect of oral supplementation of composite leaf extract of medicinal plants on biomarkers of oxidative stress in induced diabetic Wistar rats

Insulin modulation of Na/H antiport in rat red blood cells.

Aging, circadian disruption and neurodegeneration: Interesting interplay

Redox Biology of Aging: Focus on Novel Biomarkers