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

http://www.dietcan.net/docs/Polifenoles%20en%20alimentos%20y%20biodisponibilidad.pdf

Polyphenols: food sources and bioavailability

Polyphenols constitute one of the most numerous and ubiquitous groups of plant metabolites and are an integral part of both human and animal diets. Ranging from simple phenolic molecules to highly polymerized compounds with molecular weights of greater than 30,000 Da, the occurrence of this complex group of substances in plant foods is extremely variable. Polyphenols traditionally have been considered antinutrients by animal nutritionists, because of the adverse effect of tannins, one type of polyphenol, on protein digestibility. However, recent interest in food phenolics has increased greatly, owing to their antioxidant capacity (free radical scavenging and metal chelating activities) and their possible beneficial implications in human health, such as in the treatment and prevention of cancer, cardiovascular disease, and other pathologies. Much of the literature refers to a single group of plant phenolics, the flavonoids. This review offers an overview of the nutritional effects of the main groups of polyphenolic compounds, including their metabolism, effects on nutrient bioavailability, and antioxidant activity, as well as a brief description of the chemistry of polyphenols and their occurrence in plant foods.

Polyphenols: Chemistry, Dietary Sources, Metabolism, and Nutritional Significance

This report is the continuation of two earlier reports that defined human arterial intima and precursors of advanced atherosclerotic lesions in humans. This report describes the characteristic components and pathogenic mechanisms of the various advanced atherosclerotic lesions. These, with the earlier definitions of precursor lesions, led to the histological classification of human atherosclerotic lesions found in the second part of this report. The Committee on Vascular Lesions also attempted to correlate the appearance of lesions noted in clinical imaging studies with histological lesion types and corresponding clinical syndromes. In the histological classification, lesions are designated by Roman numerals, which indicate the usual sequence of lesions progression. The initial (type I) lesion contains enough atherogenic lipoprotein to elicit an increase in macrophages and formation of scattered macrophage foam cells. As in subsequent lesion types, the changes are more marked in locations of arteries with adaptive intimal thickening. (Adaptive thickenings, which are present at constant locations in everyone from birth, do not obstruct the lumen and represent adaptations to local mechanical forces). Type II lesions consist primarily of layers of macrophage foam cells and lipid-laden smooth muscle cells and include lesions grossly designated as fatty streaks. Type III is the intermediate stage between type II and type IV (atheroma, a lesion that is potentially symptom-producing). In addition to the lipid-laden cells of type II, type III lesions contain scattered collections of extracellular lipid droplets and particles that disrupt the coherence of some intimal smooth muscle cells. This extracellular lipid is the immediate precursor of the larger, confluent, and more disruptive core of extracellular lipid that characterizes type IV lesions. Beginning around the fourth decade of life, lesions that usually have a lipid core may also contain thick layers of fibrous connective tissue (type V lesion) and/or fissure, hematoma, and thrombus (type VI lesion). Some type V lesions are largely calcified (type Vb), and some consist mainly of fibrous connective tissue and little or no accumulated lipid or calcium (type Vc).

A Definition of Advanced Types of Atherosclerotic Lesions and a Histological Classification of Atherosclerosis A Report From the Committee on Vascular Lesions of the Council on Arteriosclerosis, American Heart Association

Resveratrol, a constituent of red wine, has long been suspected to have cardioprotective effects. Interest in this compound has been renewed in recent years, first from its identification as a chemopreventive agent for skin cancer, and subsequently from reports that it activates sirtuin deacetylases and extends the lifespans of lower organisms. Despite scepticism concerning its bioavailability, a growing body of in vivo evidence indicates that resveratrol has protective effects in rodent models of stress and disease. Here, we provide a comprehensive and critical review of the in vivo data on resveratrol, and consider its potential as a therapeutic for humans.

Therapeutic potential of resveratrol: the in vivo evidence.

Chylomicrons from patients with Type V hyperlipoproteinemia inhibit platelet function

Polyphenols and Flavonoids Protect LDL Against Atherogenic Modifications

The contribution of the macrophage receptor for oxidized LDL to its cellular uptake

Intralipid (Kabi Vitrum Inc, Alameda, CA) infusion into normal volunteers results in substantial elevation in serum triglyceride, phospholipids, and free cholesterol concentrations. Platelet aggregation induced in vitro in platelet-rich plasma by collagen or ADP was significantly reduced by up to 40% and 45%, respectively, during the infusion period but returned to preinfusion levels 18 hours after the end of the infusion. In parallel, platelet lipid composition was also affected. Platelet free cholesterol content was reduced by up to 20% during the infusion of Intralipid, whereas platelet triglyceride and phospholipid contents increased by 3.5-fold and twofold, respectively. Eighteen hours after the end of the infusion, both platelet cholesterol and triglyceride returned to preinfusion levels, but platelet phospholipid was still elevated. Both components of Intralipid (liposomes and triglyceride-phospholipid particles) were able to decrease in vitro platelet aggregation and platelet cholesterol content. Our results demonstrate decreased platelet function induced by Intralipid infusion into humans, which was associated with reduced platelet cholesterol content. These results suggest possible antiatherogenic effects of infusing Intralipid in humans.

Intralipid infusion into humans reduces in vitro platelet aggregation and alters platelet lipid composition

Determination of the cellular uptake of macrocyclic iron(III) complexes by a facile method, accompanied by cell viability tests under both basal and induced oxidative stress, demonstrates that protection against intracellular oxidative stress requires reasonably high internalization and favorable anti/prooxidant profiles. Of the four tested complexes, only amphipolar iron(III) corrole met these criteria.

Michael Aviram

Papers

Chylomicrons from patients with Type V hyperlipoproteinemia inhibit platelet function

Polyphenols and Flavonoids Protect LDL Against Atherogenic Modifications

The contribution of the macrophage receptor for oxidized LDL to its cellular uptake

Intralipid infusion into humans reduces in vitro platelet aggregation and alters platelet lipid composition

Variables that influence cellular uptake and cytotoxic/cytoprotective effects of macrocyclic iron complexes.