Nonroutine Use of Intra-Aortic Balloon Pump in Cardiogenic Shock Complicating Myocardial Infarction With Successful and Unsuccessful Primary Percutaneous Coronary Intervention

Objectives

The authors sought to compare outcomes of patients with myocardial infarction and cardiogenic shock (CS) treated with percutaneous coronary intervention (PCI) with or without intra-aortic balloon pump (IABP) support according to final epicardial flow in the infarct-related artery.

Curcumin- and natural extract-loaded nanofibres for potential treatment of lung and breast cancer: in vitro efficacy evaluation

Drug-eluting medical implants are more common, particularly for fighting against cancers. FDA and other drug regulatory bodies have approved many nanoformulated devices eluting active pharmaceutical ingredients and thus there is growing demand for further value- added devices. Nanofibre membranes are known for its versatility of drug incorporation and sustained drug release. We intend to fabricate natural ingredient or extract, and their combination loaded polycaprolactone (PCL) nanofibre for usage as drug-eluting stents or implants for anticancer activity against lung and breast cancers. The fabricated nanofibre membranes were characterised by scanning electron microscope for morphology, FT-IR for chemical nature and tensile testing for mechanical strengths. Release of curcumin was studied with time to find the applicability of the device as drug-eluting implant. The activity of the nanofibre membranes was tested against human breast cancer (MCF7) and lung cancer (A459) cell lines in vitro. In both the cell lines tested, 1% aloe vera and 5% curcumin-loaded PCL nanofibre exhibited 15% more cytotoxicity in comparison with the commercial drug 1% cis-Platin-loaded PCL nanofibre after 24?h incubation.     

Genome-wide patterns of identity-by-descent sharing in the French Canadian founder population

In genetics the ability to accurately describe the familial relationships among a group of individuals can be very useful. Recent statistical tools succeeded in assessing the degree of relatedness up to 6–7 generations with good power using dense genome-wide single-nucleotide polymorphism data to estimate the extent of identity-by-descent (IBD) sharing. It is therefore important to describe genome-wide patterns of IBD sharing for more remote and complex relatedness between individuals, such as that observed in a founder population like Quebec, Canada. Taking advantage of the extended genealogical records of the French Canadian founder population, we first compared different tools to identify regions of IBD in order to best describe genome-wide IBD sharing and its correlation with genealogical characteristics. Results showed that the extent of IBD sharing identified with FastIBD correlates best with relatedness measured using genealogical data. Total length of IBD sharing explained 85% of the genealogical kinship''s variance. In addition, we observed significantly higher sharing in pairs of individuals with at least one inbred ancestor compared with those without any. Furthermore, patterns of IBD sharing and average sharing were different across regional populations, consistent with the settlement history of Quebec. Our results suggest that, as expected, the complex relatedness present in founder populations is reflected in patterns of IBD sharing. Using these patterns, it is thus possible to gain insight on the types of distant relationships in a sample from a founder population like Quebec.     

Small molecule probes to quantify the functional fraction of a specific protein in a cell with minimal folding equilibrium shifts

Although much is known about protein folding in buffers, it remains unclear how the cellular protein homeostasis network functions as a system to partition client proteins between folded and functional, soluble and misfolded, and aggregated conformations. Herein, we develop small molecule folding probes that specifically react with the folded and functional fraction of the protein of interest, enabling fluorescence-based quantification of this fraction in cell lysate at a time point of interest. Importantly, these probes minimally perturb a protein’s folding equilibria within cells during and after cell lysis, because sufficient cellular chaperone/chaperonin holdase activity is created by rapid ATP depletion during cell lysis. The folding probe strategy and the faithful quantification of a particular protein’s functional fraction are exemplified with retroaldolase, a de novo designed enzyme, and transthyretin, a nonenzyme protein. Our findings challenge the often invoked assumption that the soluble fraction of a client protein is fully folded in the cell. Moreover, our results reveal that the partitioning of destabilized retroaldolase and transthyretin mutants between the aforementioned conformational states is strongly influenced by cytosolic proteostasis network perturbations. Overall, our results suggest that applying a chemical folding probe strategy to other client proteins offers opportunities to reveal how the proteostasis network functions as a system to regulate the folding and function of individual client proteins in vivo.All proteins are biosynthesized as linear chains, and most need to fold into 3D structures to function. Studies on protein folding in buffers have revealed that a kinetic competition typically exists between protein folding, misfolding, and aggregation. It is the role of the protein homeostasis or proteostasis network in each subcellular compartment to regulate this competition and keep the folded and functional proteome within the physiological concentration range, while minimizing misfolding and aggregation in the face of stresses (1–4). It remains a challenge to discern how the proteostasis network affects the folding of proteins into biologically active conformations required for function in vivo (5).Current methodologies allow for quantification of the partitioning of a protein of interest (POI) between soluble and aggregated states but cannot determine the proportion of the soluble population that is properly folded and functional. Published folding probes have the potential to report on the folded fraction in cells or cell lysate (6–9); however, the extent to which they shift folding equilibria and quantify the folded and functional fraction faithfully has not been studied. Herein, we create POI folding probes by adapting the principle of activity-based protein profiling (10) to quantify the soluble folded and functional fraction of a particular protein in a cell lysate. We seek folding probes that bind to and selectively react with only the folded and functional state of a POI in a cell, leaving the nonfunctional states and other cellular proteins unmodified (Fig. 1A).Open in a separate windowFig. 1.A small molecule folding probe strategy to quantify the soluble folded and functional fraction of a POI in a cell lysate. (A) Overview of the general strategy to selectively covalently label a folded and functional POI without labeling its nonfunctional conformations and other cellular proteins. (B) The experimental scheme to quantify the ratio of the soluble POI that is functional (R_f).Fluorescent folding probes for the de novo-designed enzyme, retroaldolase (RA) (11), and fluorogenic folding probes (12) for the nonenzyme protein, transthyretin (TTR), were developed and scrutinized. We show that destabilized mutant RA and TTR proteins partition into folded and functional as well as misfolded soluble conformations and that this partitioning is sensitive to proteostasis network perturbations. Experiments show that a snapshot of the distribution between folded and functional vs. soluble and misfolded conformational states can be preserved during the small molecule folding probe labeling period, provided that the cellular chaperone holdase activity is sufficient, achieved by rapid ATP depletion in parallel with cell lysis. Sufficient chaperone/chaperonin holdase activity minimizes changes in the folded and functional concentration associated with probe binding and reaction with the POI and renders the relative folding and conjugation rates much less influential.     

Total left main coronary artery occlusion in a female patient after AVSD surgical repair in childhood as a cause of non ST elevation myocardial infarction

A case of a 51-year-old woman with symptoms of non-ST-segment elevation acute coronary syndrome and concomitant atrial flutter is presented. Patient underwent atrioventricular septal defect repair in childhood. Coronary angiography showed total occlusion of left main coronary artery and massive collateral network originating from right coronary artery supplying entire left coronary artery. Ablation of atrial flutter had been performed and patient was subsequently submitted to mitral valve replacement, tricuspid valvuloplasty and coronary artery bypass grafting. The potential causes of left main occlusion are in this case discussed.     

Structural insights into biased G protein-coupled receptor signaling revealed by fluorescence spectroscopy

G protein-coupled receptors (GPCRs) are seven-transmembrane proteins that mediate most cellular responses to hormones and neurotransmitters, representing the largest group of therapeutic targets. Recent studies show that some GPCRs signal through both G protein and arrestin pathways in a ligand-specific manner. Ligands that direct signaling through a specific pathway are known as biased ligands. The arginine-vasopressin type 2 receptor (V2R), a prototypical peptide-activated GPCR, is an ideal model system to investigate the structural basis of biased signaling. Although the native hormone arginine-vasopressin leads to activation of both the stimulatory G protein (Gs) for the adenylyl cyclase and arrestin pathways, synthetic ligands exhibit highly biased signaling through either Gs alone or arrestin alone. We used purified V2R stabilized in neutral amphipols and developed fluorescence-based assays to investigate the structural basis of biased signaling for the V2R. Our studies demonstrate that the Gs-biased agonist stabilizes a conformation that is distinct from that stabilized by the arrestin-biased agonists. This study provides unique insights into the structural mechanisms of GPCR activation by biased ligands that may be relevant to the design of pathway-biased drugs.