Exhaustive additivity suggests a new stage not an alternative model: A commentary on Fowler, Hofer and Lipitkas

Comments on the article by B. Fowler et al (see record 2000-15213-005) in which they observed that nitrous oxide, an inhalation anaethetic, does not interact with experimental manipulations derived from the additive factors literature. They proposed a 2-tiered cognitive-energetical model to account for the apparent "exhaustive additivity." This model assumes that nitrous oxide affects a lower tier resulting in a non-selective effect on an upper tier, which is comprised of energetic mechanisms that are selectively linked to processing stages. In this commentary, it is argued that the "exhaustive additivity" can easily be accommodated by linear stage models. The findings of Fowler et al suggest a new stage rather than a new model. Moreover, their new model seems to predict "exhaustive interaction" rather than "exhaustive additivity." It is concluded that Fowler et al may have a highly interesting finding, but not for the reasons they submitted when accounting for the "exhaustive additivity" displayed by nitrous oxide. (PsycINFO Database Record (c) 2000 APA, all rights reserved

A case report of a myocardial ischaemic attack: a novel hyperenhancement pattern on cardiac magnetic resonance in focal ischaemic injury

Background Delayed enhancement cardiac magnetic resonance (DE-CMR) is the reference standard for the non-invasive assessment of myocardial fibrosis. DE-CMR is able to distinguish ischaemic from non-ischaemic aetiologies based on differences in hyperenhancement distribution patterns. Hyperenhancement caused by ischaemic injury typically involves the endocardium, while hyperenhancement confined to the mid- and epicardial layers of the myocardium suggests a non-ischaemic aetiology. Case summary This is a case of a 20-year-old male with an unremarkable medical history with an acute ST-elevation myocardial infarction. DE-CMR revealed two distinct patterns of hyperenhancement: (i) a 'normal' wavefront-ischaemic pattern, and (ii) multiple atypical mid-wall and epicardial areas of focal hyperenhancement. Invasive coronary angiography (ICA) and coronary computed tomographic angiography (CCTA) showed multiple intracoronary thrombi and distal emboli in the left anterior descending, ramus circumflexus, and in smaller branches of the LCA. All hyperenhancement patterns observed on DE-CMR perfectly matched the distribution territories of the affected coronary arteries. Discussion This case with an acute myocardial infarction showed intracoronary thrombi and emboli on ICA and CCTA. Interestingly, DE-CMR showed two different patterns of hyperenhancement in the same territories of the coronary thrombi. This observation may challenge the concept that these non-endocardial areas of hyperenhancement on DE-CMR are always of non-ischaemic aetiology. It is hypothesized that occlusion of smaller distal branches of the coronary arteries may result in mid-wall or epicardial fibrosis as opposed to subendocardial fibrosis commonly found in patients with a large epicardial coronary occlusion. Clinicians should be aware of these atypical patterns to be able to initiate adequate medical therapy