The endothelium plays a critical role in controlling resistance artery diameter, and thus blood flow and blood pressure. Circulating chemical mediators and physical forces act directly on the endothelium to release diffusible relaxing factors, such as NO, and elicit hyperpolarization of the endothelial cell membrane potential, which spreads to the underlying smooth muscle cells via gap junctions (EDH). It has long been known that arterial vasoconstriction in response to agonists is limited by the endothelium, but the question of how contraction of smooth muscle cells leads to activation of the endothelium (myoendothelial feedback) has, until recently, received little attention. Initial studies proposed the permissive movement of Ca(2+) ions from smooth muscle to endothelial cells to elicit release of NO. However, more recent evidence supports the notion that flux of IP(3) leading to localized Ca(2+) events within spatially restricted myoendothelial projections and activation of EDH may underlie myoendothelial feedback. In this perspective, we review recent data which supports the functional role of myoendothelial projections in smooth muscle to endothelial communication. We also discuss the functional evidence supporting the notion that EDH, as opposed to NO, is the primary mediator of myoendothelial feedback in resistance arteries.
In their effort to measure yarn hairiness at high speed, the commercially available yarn hairiness testers resort to indirect techniques. Measurement of true length of all hairs can only be done by observing the yarn under a microscope and obtaining a trace of hairs. An attempt was made in this work to automate this task using digital image processing. The challenges were two-fold. The first was development of an algorithm capable of analysing yarn images taken under varying lighting conditions and varying yarn positions. The second was determination of minimum requirement of the image-capturing instrument. Both of these have been reported in this work. A new hairiness index has been proposed and suggested as a better indicator of hairiness than the traditional definition.
Antegrade cerebral perfusion was associated with improved survival and neurologic outcomes in patients undergoing aortic arch surgery, especially for cases requiring prolonged aortic arch repair periods.
Poor reporting quality may contribute to irreproducibility of results and failed ‘bench-to-bedside’ translation. Consequently, guidelines have been developed to improve the complete and transparent reporting of
in vivo
preclinical studies. To examine the impact of such guidelines on core methodological and analytical reporting items in the preclinical anesthesiology literature, we sampled a cohort of studies. Preclinical
in vivo
studies published in
Anesthesiology
,
Anesthesia & Analgesia
,
Anaesthesia
, and the
British Journal of Anaesthesia
(2008–2009, 2014–2016) were identified. Data was extracted independently and in duplicate. Reporting completeness was assessed using the National Institutes of Health Principles and Guidelines for Reporting Preclinical Research. Risk ratios were used for comparative analyses. Of 7615 screened articles, 604 met our inclusion criteria and included experiments reporting on 52 490 animals. The most common topic of investigation was pain and analgesia (30%), rodents were most frequently used (77%), and studies were most commonly conducted in the United States (36%). Use of preclinical reporting guidelines was listed in 10% of applicable articles. A minority of studies fully reported on replicates (0.3%), randomization (10%), blinding (12%), sample-size estimation (3%), and inclusion/exclusion criteria (5%). Statistics were well reported (81%). Comparative analysis demonstrated few differences in reporting rigor between journals, including those that endorsed reporting guidelines. Principal items of study design were infrequently reported, with few differences between journals. Methods to improve implementation and adherence to community-based reporting guidelines may be necessary to increase transparent and consistent reporting in the preclinical anesthesiology literature.
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