The Year in Perioperative Echocardiography: Selected Highlights from 2023.

This article is the eighth in an annual series reviewing the research highlights of the year pertaining to the subspecialty of perioperative echocardiography for the Journal of Cardiothoracic and Vascular Anesthesia. The authors thank the editor-in-chief, Dr Kaplan, and the editorial board for the opportunity to continue this series. In most cases, these will be research articles targeted at the perioperative echocardiographic diagnosis and treatment of patients after cardiothoracic surgery; but in some cases, the articles will target the use of perioperative echocardiography in general.

Partial Metal Ion Saturation of C2 Domains Primes Synaptotagmin 1-Membrane Interactions.

Synaptotagmin 1 (Syt1) is an integral membrane protein whose phospholipid-binding tandem C2 domains, C2A and C2B, act as Ca sensors of neurotransmitter release. Our objective was to understand the role of individual metal-ion binding sites of these domains in the membrane association process. We used Pb, a structural and functional surrogate of Ca, to generate the protein states with well-defined protein-metal ion stoichiometry.

High affinity interactions of Pb with synaptotagmin I.

Lead (Pb) is a potent neurotoxin that disrupts synaptic neurotransmission. We report that Synaptotagmin I (SytI), a key regulator of Ca2+-evoked neurotransmitter release, has two high-affinity Pb2+ binding sites that belong to its cytosolic C2A and C2B domains. The crystal structures of Pb2+-complexed C2 domains revealed that protein-bound Pb2+ ions have holodirected coordination geometries and all-oxygen coordination spheres.

Non-Native Metal Ion Reveals the Role of Electrostatics in Synaptotagmin 1-Membrane Interactions.

C2 domains are independently folded modules that often target their host proteins to anionic membranes in a Ca-dependent manner. In these cases, membrane association is triggered by Ca binding to the negatively charged loop region of the C2 domain. Here, we used a non-native metal ion, Cd, in lieu of Ca to gain insight into the contributions made by long-range Coulombic interactions and direct metal ion-lipid bridging to membrane binding.

"We are out of balance here": a Hmong cultural model of diabetes.

A Hmong cultural model of type 2 diabetes has not been described. We analyzed 20 group discussions during 21 group visits over 1 year with 39 Hmong adults with type 2 diabetes in order to describe a model that underlines their discussions. These Hmong adults attribute their diabetes to their refugee experience.