Current Pharmaceutical Design - Volume 10, Issue 14, 2004

Haemostasis is a finely balanced and complex process ideally initiated only in response to disruption of the vascular endothelium as a means of preventing loss of blood from an injured vessel. Deviations from the ideal can lead to serious disease. Firstly, thrombosis, which arises as a consequence of inappropriate platelet-platelet interactions at a region of vessel damaged by atherosclerosis, can lead to occlusion of th Read More

The intravenous Glycoprotein (GP) IIb / IIIa antagonists are potent antiplatelet agents that are particularly effective in patients who undergo percutaneous coronary intervention (PCI). Questions remain about their benefit in the setting of primary PCI, as well as in patients with acute coronary syndromes who do not undergo PCI. The dosing of these drugs is critical to their efficacy and for some agents may not yet be Read More

GPIIb / IIIa receptor antagonists block fibrinogen binding to platelets and as a result inhibit platelet aggregation. They are very potent inhibitors due to the critical role fibrinogen binding plays in platelet aggregation. When given intravenously these drugs have been shown to be very effective as adjuvant therapy in percutaneous coronary intervention and in acute coronary syndromes. However, despite being as potent as their int Read More

Various oral platelet GPIIb / IIIa receptor antagonists have undergone clinical investigations, but to date without success. Various factors have been proposed to explain their failure such as low affinity for the receptor, large peak / trough ratio, low bioavailability, partial agonist activity and pro-aggregatory effect. Efforts to discover a truly effective, safe, oral antagonist led to the discovery of UR-3216 (Fig. 1). The active form of Read More

Extensive study in integrin research has seen the platelet specific receptor αIIbβ3 (Glycoprotein GPIIb / IIIa) under much scrutiny, and provided vast information as to the workings of this integrin within the blood. Glanzmann's thrombasthenia, a rare autosomal recessive bleeding disorder, highlights the vital role played by this receptor in platelet function [1]. Glanzmann's thrombasthenic platelets fail to aggregate due to a l Read More

The diatomic molecule of oxygen contains two uncoupled electrons and can therefore undergo reduction, yielding several different oxygen metabolites, which are collectively called Reactive Oxygen Species or ROS. They are invariably produced in aerobic environments through a variety of mechanisms, which include electron “leakage” during biologic oxidations, action of flavin dehydrogenases and specific membrane ass Read More

Nitric oxide (NO), a free radical molecule, produced by NO synthase (NOS) in the body exerts a number of pathophysiological actions due to its chemical reactivity. Low amounts of NO (nM) normally produced by constitutive NOS play a critical role in different physiological events such as vasodilation and neurotransmission. Higher amounts of NO (μM) locally and spatially produced by inducible NOS during inflammation act Read More

Oxidative agents are generated in large amounts during inflammation. These highly reactive intermediates interact with several extracellular and intracellular molecules and with each other, thus generating a complex network of responses culminating in an outcome that may be detrimental or beneficial for the host. Alongside with the well known systems involved in production of reactive oxygen species or reactive nitrogen s Read More

Risk of gastrointestinal cancers is closely related to increased levels of oxidants in the balance between oxidant and anti-oxidant agents. A possible explanation of this epidemiological observation is the local loss of the epithelial barrier function with a focal inflammatory response. Accordingly, chronic inflammatory diseases represent well-known risk factors for cancer and, on the other hand, it is known that anti-inflammatory a Read More

NO is considered to be an ubiquitous endogenous system which takes part in body's homeostatic regulations and in pathological events. NO derives from a) the actions of enzymes, the NO Synthases (NOS), which are constitutives (endothelial NOS (eNOS) and nervous NOS (nNOS)) and generate small amounts of NO and have homeostatic functions: and b) from the actions of inducible NOS (iNOS), which generate large amounts o Read More

Living beings have evolved over the past two billon years through adaptation, to an increasing atmospheric oxygen concentration, by both taking advantage of oxygen activating function and developing a complex control network. In these regards, potentially damaging species (reactive oxygen, nitrogen and chlorine species) arise as by-products of metabolism and also work as physiological mediators and signalling mole Read More

A major cause for endothelial dysfunction in essential hypertension is decreased availability of nitric oxide (NO). Impairment in NO bioavailability is likely to be the consequence of multiple mechanisms affecting NO synthesis as well as NO breakdown. An alteration in the redox balance in endothelial cells leads to increased superoxide anion production and oxidative stress. This in turn not only exerts negative effects on vas Read More

Oxidative stress is a condition in which oxidant metabolites exert their toxic effect because of an increased production or an altered cellular mechanism of protection. The heart needs oxygen avidly and, although it has powerful defence mechanisms, it is susceptible to oxidative stress, which occurs, for instance, during postischaemic reperfusion. Ischaemia causes alterations in the defence mechanisms against oxygen f Read More