BACKGROUND Patients with supraventricular tachycardia (SVT) commonly present to the emergency department (ED). Current guidelines do not recommend routine pathology testing and a report on the topic has questioned their role. A systematic review concluded that troponin testing is commonly performed with a high proportion of positive findings, but these results were not associated with major adverse cardiac events. The conclusions of this review were limited by paucity of data and heterogeneity among studies.

Dear editor, After sustaining severe traumatic brain injury (TBI), patients frequently require invasive mechanical ventilation (MV). However, up to 26% of patients require tracheostomy due to failure to wean from the ventilator.[1] The decision of when to perform tracheostomy is important as it balances the risk between avoiding prolonged MV and avoiding risk of tracheostomy. Early predictors for tracheostomy, i.e., clinical factors when patients first present to an Emergency Department after trauma or when patient first arrive at a regional trauma center, can help clinicians’ medical decision-making process.

Using directed mutagenesis and phage display on a soluble fragment of the human immunoglobulin super-family receptor ILT2 (synonyms: LIR1, MIR7, CD85j), we have selected a range of mutants with binding affinities enhanced by up to 168,000-fold towards the conserved region of major histocompatibility complex (MHC) class I molecules. Produced in a dimeric form, either by chemical cross-linking with bivalent polyethylene glycol (PEG) derivatives or as a genetic fusion with human IgG Fc-fragment, the mutants exhibited a further increase in ligand-binding strength due to the avidity effect, with resident half-times (t(1/2)) on the surface of MHC I-positive cells of many hours. The novel compounds antagonized the interaction of CD8 co-receptor with MHC I in vitro without affecting the peptide-specific binding of T-cell receptors (TCRs). In both cytokine-release assays and cell-killing experiments the engineered receptors inhibited the activation of CD8(+) cytotoxic T lymphocytes (CTLs) in the presence of their target cells, with subnanomolar potency and in a dose-dependent manner. As a selective inhibitor of CD8(+) CTL responses, the engineered high affinity ILT2 receptor presents a new tool for studying the activation mechanism of different subsets of CTLs and could have potential for the development of novel autoimmunity therapies.
Amino Acid Sequence ; Antigens, CD ; chemistry ; genetics ; pharmacology ; Autoimmunity ; Biological Assay ; Cell Line ; Cytotoxicity, Immunologic ; genetics ; immunology ; Dose-Response Relationship, Immunologic ; Humans ; Immunoglobulins ; immunology ; metabolism ; Immunologic Factors ; chemistry ; genetics ; pharmacology ; Kinetics ; Leukocyte Immunoglobulin-like Receptor B1 ; Lymphocyte Activation ; genetics ; immunology ; Major Histocompatibility Complex ; genetics ; immunology ; Molecular Sequence Data ; Molecular Targeted Therapy ; Mutagenesis, Site-Directed ; Peptide Library ; Polyethylene Glycols ; Protein Binding ; genetics ; immunology ; Receptors, Immunologic ; chemistry ; genetics ; Recombinant Fusion Proteins ; genetics ; metabolism ; T-Lymphocytes, Cytotoxic ; immunology ; metabolism