The "Crater" Arteriotomy: A Technique Aiding Precise Intimal Apposition in End-to-side Microvascular Anastomosis.

End-to-side arterial anastomoses require a high level of technical competency. The main challenge to a successfully patent anastomosis is intimal interposition during the standardized microvascular suturing. Technical errors during arteriotomy pose a significant challenge for the microsurgical technique, making the end-to-side anastomosis prone to failure. We describe a basic yet fundamental method of performing an arteriotomy, the "crater" technique, which facilitates good visualization of all vessel layers before placement of microsurgical sutures. Using curved microsurgical scissors, the adventitia layer is dissected off the outer surface of the side vessel, a V-shaped cut is then made obliquely at a 30-45 degrees angle to the longitudinal axis of the vessel, and a full thickness oblique cut is made along an elliptical circumference, as the curved scissors enable the creation of a slope-like crater. This concept ensures the intimal layer is adequately exposed through the complete circumference of the arteriotomy rim, while enabling a variable increase in the arterial wall hypotenuse-width circumference. When performed in a standardized manner, the crater arteriotomy can minimize the risk of endothelial misalignment and further technical errors during suturing, thus minimizing the risk of anastomotic failure.

Highly Selective Fluorimetric Turn-Off Detection of Copper(II) by Two Different Mechanisms in Calix[4]arene-Based Chemosensors and Chemodosimeters.

Isoxazolo-pyrene tethered calix[4]arenes selectively detect copper(II) ions without interference from related perchlorate ions. The fluorescence emission of the probes, synthesised by nitrile oxide alkyne cycloaddition, and characterised by spectroscopic and crystallographic data, is rapidly reduced by Cu(II) ions. Detection limits are in the micromolar or sub-micromolar range (0.3-3.6 µM) based on a 1 : 1 sensor:analyte interaction. Voltammetric behaviour and 1 H NMR data provide new insights into the sensing mechanism which is dependent on the calixarene substitution pattern. When the calixarene lower rim is fully substituted, Cu(II) detection occurs through a traditional chelation mechanism. In contrast, for calixarenes 1,3-disubstituted on the lower rim, detection takes place through a chemodosimetric redox reaction. The isolation of a calix[4]diquinone from the reaction with excess Cu(ClO4 )2 provides confirmation that the sensor-analyte interaction culminates in irreversible sensor oxidation.