ECG patterns suggestive of high-risk coronary anatomy in non-ST-segment elevation acute coronary syndrome - an analysis of real-world patients.

Introduction: Electrocardiographic (ECG) patterns suggestive of high-risk coronary anatomy are indications for an urgent invasive approach in non-ST-segment elevation acute coronary syndrome (NSTE-ACS). Aim: To estimate the frequency of the observed phenomenon and assess the clinical characteristics of NSTE-ACS subjects associated with Wellens syndrome, the de Winter sign, or ST-segment depressions by ≥ 1 mm in ≥ 6 classic ECG leads with simultaneous ST-segment elevation in aVR and/or V1. Material and methods: Out of 207 pre-screened subjects diagnosed with NSTE-ACS, 64 patients (26 women and 38 men) with complete medical records (including admission ECG and coronary angiography during the index hospitalization), and significant culprit stenosis or occlusion of the left main coronary artery (LMCA) or the proximal/middle segment of the left anterior descending artery (LAD) entered the final analysis. Clinical characteristics of patients exhibiting any of the high-risk ECG patterns was compared to their counterparts with significant lesions in LMCA or proximal/middle LAD without any of the high-risk ECG patterns. Results: Among 64 patients with significant culprit lesions in LMCA or LAD, 19 (29.69%) exhibited one of the high-risk ECG patterns: Wellens syndrome (n = 10), the de Winter sign (n = 0), or multiple ST-segment depressions (n = 9). Clinical characteristics were comparable in 19 NSTE-ACS patients with the high-risk ECG patterns and their 45 counterparts. Conclusions: Because ECG patterns suggestive of high-risk coronary anatomy are relatively frequent in patients with NSTE-ACS and culprit lesions in LMCA or LAD, their early recognition is of clinical importance.

Grafting from surfaces for "everyone": ARGET ATRP in the presence of air.

Atom-transfer radical polymerization (ATRP) is one of the controlled/living radical polymerizations yielding well-defined (co)polymers, nanocomposites, molecular hybrids, and bioconjugates. ATRP, as in any radical process, has to be carried out in rigorously deoxygenated systems to prevent trapping of propagating radicals by oxygen. Herein, we report that ATRP can be performed in the presence of limited amount of air and with a very small (typically ppm) amount of copper catalyst together with an appropriate reducing agent. This technique has been successfully applied to the preparation of densely grafted polymer brushes, poly(n-butyl acrylate) homopolymer, and poly(n-butyl acrylate)-block-polystyrene copolymer from silicon wafers (0.4 chains/nm2). This simple new method of grafting well-defined polymers does not require any special equipment and can be carried out in vials or jars without deoxygenation. The grafting for "everyone" technique is especially useful for wafers and other large objects and may be also applied for molecular hybrids and bioconjugates.

Diminishing catalyst concentration in atom transfer radical polymerization with reducing agents.

The concept of initiators for continuous activator regeneration (ICAR) in atom transfer radical polymerization (ATRP) is introduced, whereby a constant source of organic free radicals works to regenerate the Cu(I) activator, which is otherwise consumed in termination reactions when used at very low concentrations. With this technique, controlled synthesis of polystyrene and poly(methyl methacrylate) (Mw/Mn < 1.2) can be implemented with catalyst concentrations between 10 and 50 ppm, where its removal or recycling would be unwarranted for many applications. Additionally, various organic reducing agents (derivatives of hydrazine and phenol) are used to continuously regenerate the Cu(I) activator in activators regenerated by electron transfer (ARGET) ATRP. Controlled polymer synthesis of acrylates (Mw/Mn < 1.2) is realized with catalyst concentrations as low as 50 ppm. The rational selection of suitable Cu complexing ligands {tris[2-(dimethylamino)ethyl]amine (Me6TREN) and tris[(2-pyridyl)methyl]amine (TPMA)} is discussed in regards to specific side reactions in each technique (i.e., complex dissociation, acid evolution, and reducing agent complexation). Additionally, mechanistic studies and kinetic modeling are used to optimize each system. The performance of the selected catalysts/reducing agents in homo and block (co)polymerizations is evaluated.