Size matters: a view of selenocysteine incorporation from the ribosome

This review focuses on the known factors required for selenocysteine (Sec) incorporation in eukaryotes and highlights recent findings that have compelled us to propose a new model for the mechanism of Sec incorporation. In light of this data we also review the controversial aspects of the previous modelspecifically regarding the proposed interaction between SBP2 and eEFSec. In addition, the relevance of two recently discovered factors in the recoding of Sec are reviewed. The role of the ribosome in this process is emphasized along with a detailed analysis of kinkturn structures present in the ribosome and the L7Ae RNA-binding motif present in SBP2 and other proteins

Epigenetic Activation of a Subset of mRNAs by eIF4E Explains Its Effects on Cell Proliferation

BACKGROUND: Translation deregulation is an important mechanism that causes aberrant cell growth, proliferation and survival. eIF4E, the mRNA 5′ cap-binding protein, plays a major role in translational control. To understand how eIF4E affects cell proliferation and survival, we studied mRNA targets that are translationally responsive to eIF4E. METHODOLOGY/PRINCIPAL FINDINGS: Microarray analysis of polysomal mRNA from an eIF4E-inducible NIH 3T3 cell line was performed. Inducible expression of eIF4E resulted in increased translation of defined sets of mRNAs. Many of the mRNAs are novel targets, including those that encode large- and small-subunit ribosomal proteins and cell growth-related factors. In addition, there was augmented translation of mRNAs encoding anti-apoptotic proteins, which conferred resistance to endoplasmic reticulum-mediated apoptosis. CONCLUSIONS/SIGNIFICANCE: Our results shed new light on the mechanisms by which eIF4E prevents apoptosis and transforms cells. Downregulation of eIF4E and its downstream targets is a potential therapeutic option for the development of novel anti-cancer drugs

Prehospital Lactate Measurement by Emergency Medical Services in Patients Meeting Sepsis Criteria

Introduction: We aimed to pilot test the delivery of sepsis education to emergency medical services (EMS) providers and the feasibility of equipping them with temporal artery thermometers (TATs) and handheld lactate meters to aid in the prehospital recognition of sepsis. Methods: This study used a convenience sample of prehospital patients meeting established criteria for sepsis. Paramedics received education on systemic inflammatory response syndrome (SIRS) criteria, were trained in the use of TATs and hand-held lactate meters, and enrolled patients who had a recent history of infection, met ≥ 2 SIRS criteria, and were being transported to a participating hospital. Blood lactate was measured by paramedics in the prehospital setting and again in the emergency department (ED) via usual care. Paramedics entered data using an online database accessible at the point of care. Results: Prehospital lactate values obtained by paramedics ranged from 0.8 to 9.8 mmol/L, and an elevated lactate (i.e. ≥ 4.0) was documented in 13 of 112 enrolled patients (12%). The unadjusted correlation of prehospital and ED lactate values was 0.57 (p< 0.001). The median interval between paramedic assessment of blood lactate and the electronic posting of the ED-measured lactate value in the hospital record was 111 minutes. Overall, 91 patients (81%) were hospitalized after ED evaluation, 27 (24%) were ultimately diagnosed with sepsis, and 3 (3%) died during hospitalization. Subjects with elevated prehospital lactate were somewhat more likely to have been admitted to the intensive care unit (23% vs 15%) and to have been diagnosed with sepsis (38% vs 22%) than those with normal lactate levels, but these differences were not statistically significant. Conclusion: In this pilot, EMS use of a combination of objective SIRS criteria, subjective assessment of infection, and blood lactate measurements did not achieve a level of diagnostic accuracy for sepsis that would warrant hospital prenotification and committed resources at a receiving hospital based on EMS assessment alone. Nevertheless, this work provides an early model for increasing EMS awareness and the implementation of novel devices that may enhance the prehospital assessment for sepsis. Additional translational research studies with larger numbers of patients and more robust methods are needed. [West J Emerg Med. 2016;17(5)648-655.]

Removal of anti-Gal\u3b11,3Gal xenoantibodies with an injectable polymer

Preformed and elicited Ab's against the Gal\u3b11,3Gal terminating carbohydrate chains (\u3b1Gal Ab's) are the primary cause of hyperacute and acute vascular xenograft rejection in pig-to-primate transplantation. \u3b1Gal Ab's are produced by long-lived Ab-producing cells that are not susceptible to pharmacological immunosuppression. We reasoned that antigen-specific elimination of \u3b1Gal Ab's might be achieved in vivo by systemic administration of nonimmunogenic polyvalent \u3b1Gal structures with high avidity for \u3b1Gal Ab's. We devised GAS914, a soluble trisaccharide-polylysine conjugate of approximately 500 kDa that effectively competes for \u3b1Gal binding by \u3b1Gal IgM (IC50, 43 nM) and IgG (IC50, 28 nM) in vitro. Injections of GAS914 in cynomolgus monkeys, at the dose of 1 mg/kg, resulted in the immediate decrease of more than 90% of circulating \u3b1Gal Ab's and serum anti-pig cytotoxicity. In baboons, repeated injections of GAS914 effectively reduced both circulating \u3b1Gal Ab's and cytotoxicity over several months. Studies with [14C]GAS914 in rhesus monkeys and Gal-/- mice indicate that GAS914 binds to circulating \u3b1Gal Ab's and that the complex is quickly metabolized by the liver and excreted by the kidney. Remarkably, posttreatment \u3b1Gal Ab titers never exceeded pretreatment levels and no sensitization to either \u3b1Gal or the polylysine backbone has been observed. Furthermore there was no apparent acute or chronic toxicity associated with GAS914 treatment in primates. We conclude that GAS914 may be used therapeutically for the specific removal of \u3b1Gal Ab's