Intracardiac echocardiographic-guided right-sided cardiac biopsy: Case series and literature review.

Endomyocardial biopsy (EMB) is a common procedure used to aid in the diagnosis of diffuse myocardial diseases and, less commonly, in the diagnosis of cardiac tumors. As cardiac tumors are often found in high-risk locations (ventricular free wall or atria), precision biopsy is paramount, and additional imaging, like transesophageal echocardiography is often required for guidance. The use of intracardiac echocardiography (ICE) to guide biopsy has been described, but there is no consensus on a standardized approach. We report our institutional approach with three cases of ICE-directed EMB performed with the 2.4 mm Jawz bioptome directed with an 8.5-Fr Agilis NxT steerable introducer. All cases were performed under guidance with the AcuNav ICE probe. There were no procedural complications and a definitive diagnosis was obtained in all three cases. We also review the available published cases of ICE-guided EMB in the literature-noting the different procedural approaches, complication rate, and diagnostic yield. There were only two negative biopsies reported among the published cases and no reported complications. Our review of all these cases suggests that ICE-guidance for EMB is superior to other forms of imaging in its ease of use and high definition of right-sided cardiac structures. We also feel that the use of the Agilis steerable sheath allows for more precise directing of the bioptome and is a critical component in performing a successful targeted biopsy.

Noble metals strip peptides from class II MHC proteins.

Class II major histocompatibility complex (MHC) proteins are essential for normal immune system function but also drive many autoimmune responses. They bind peptide antigens in endosomes and present them on the cell surface for recognition by CD4(+) T cells. A small molecule could potentially block an autoimmune response by disrupting MHC-peptide interactions, but this has proven difficult because peptides bind tightly and dissociate slowly from MHC proteins. Using a high-throughput screening assay we discovered a class of noble metal complexes that strip peptides from human class II MHC proteins by an allosteric mechanism. Biochemical experiments indicate the metal-bound MHC protein adopts a 'peptide-empty' conformation that resembles the transition state of peptide loading. Furthermore, these metal inhibitors block the ability of antigen-presenting cells to activate T cells. This previously unknown allosteric mechanism may help resolve how gold(I) drugs affect the progress of rheumatoid arthritis and may provide a basis for developing a new class of anti-autoimmune drugs.