Functional screening for lipolytic enzymes at low temperatures resulted in the isolation of the novel cold-active esterases, EstM-N1 and EstM-N2, from a metagenomic DNA library of arctic soil samples. EstM-N1 and EstM-N2 were 395 and 407 amino acids in length, respectively, and showed the highest similarity to class C β-lactamases. However, they shared a relatively low level of sequence similarity (30%) with each other. Phylogenetic analysis of bacterial lipolytic enzymes confirmed that EstM-N1 and EstM-N2 belonged to family VIII of bacterial esterases/lipases. The (His)(6)-tagged esterases were purified to about 99% homogeneity from the soluble fraction of recombinant Escherichia coli cultures. The purified EstM-N1 and EstM-N2 retained more than 50% of maximal activity in the temperature range of 0-35 °C, with optimal temperatures of 20 °C and 30 °C, respectively. Both enzymes preferred the short acyl chains of p-nitrophenyl esters and exhibited very narrow substrate specificity, indicating that they are typical esterases. The β-lactamase activity of EstM-N1 and EstM-N2 was also detected and reached about 31% and 13% of the positive control enzyme, Bacillus cereus β-lactamase, respectively. These first cold-active esterases belonging to family VIII are expected to be useful for potential biotechnological applications as interesting biocatalysts.

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Background Considering the functional role of red blood cells (RBC) in maintaining oxygen supply to tissues, RBC transfusion can be a life-saving intervention in situations of severe bleeding or anemia. RBC transfusion is often inevitable to address intraoperative massive bleeding; it is a key component in safe perioperative patient management. Unlike general medical resources, packed RBCs (pRBCs) have limited availability because their supply relies entirely on voluntary donations. Additionally, excessive utilization of pRBCs may aggravate prognosis or increase the risk of developing infectious diseases. Appropriate perioperative RBC transfusion is, therefore, crucial for the management of patient safety and medical resource conservation. These concerns motivated us to develop the present clinical practice guideline for evidence-based efficient and safe perioperative RBC transfusion management considering the current clinical landscape. Methods This guideline was obtained after the revision and refinement of exemplary clinical practice guidelines developed in advanced countries. This was followed by rigorous evidence-based reassessment considering the healthcare environment of the country. Results This guideline covers all important aspects of perioperative RBC transfusion, such as preoperative anemia management, appropriate RBC storage period, and leukoreduction (removal of white blood cells using filters), reversal of perioperative bleeding tendency, strategies for perioperative RBC transfusion, appropriate blood management protocols, efforts to reduce blood transfusion requirements, and patient monitoring during a perioperative transfusion. Conclusions This guideline will aid decisions related to RBC transfusion in healthcare settings and minimize patient risk associated with unnecessary pRBC transfusion.

Background: Morbidly adherent placenta (MAP) may cause life-threatening postpartum hemorrhage (PPH) requiring massive transfusions. Furthermore, it could endanger the lives of both mother and baby. Despite various efforts, such as adjuvant endovascular embolization and hysterectomy, massive PPH due to MAP still occurs and is difficult to overcome. Case: Herein, we described the case of a 40-year-old woman with placenta previa totalis who experienced massive bleeding during a cesarean section. We used resuscitative endovascular balloon occlusion of the aorta (REBOA) and it improved the condition of the surgical field and the hemodynamic stability of the patient temporarily. The patient was successfully managed without further complications. Conclusions: REBOA can be used as a rescue procedure for uncontrolled bleeding situations in patients with MAPs. Anesthesiologists should consider and recommend REBOA as another resuscitative therapeutic option in the case of massive PPH.