Objective To compare the efficiency of compressive bandage dressing and drainage on the blood loss after total knee arthroplasty (TKA). Methods Patients (n=120) who visited Tianjin General Hospital Bin Hai Branch and Tianjin People's Hospital due to varus knee osteoarthritis and underwent TKA were retrospectively analyzed.There are 20 males and 100 females with, mean age was 65.18±6.88 years. Depending on whether placement of drainage, patients were divided into drainage group (60 cases) and pressure bandage dressing group (60 cases). Blood loss, blood transfusion and full blood count (FBC) were all analyzed after TKA in both groups. Results Blood loss after TKA in drainage and pressure dressing group were (1 026.85±274.44),(789.52±251.58) mL respectively. Blood loss was less severe in pressure dressing group than that in drainage group (t=4.938, P<0.01). Allogeneic transfusions were needed in 14 cases of drainage group and five cases of pres?sure bandage dressing group. The circumstances that requires blood transfusion was significantly lower in pressure bandage group than that in drainage group (χ2=5.065, P<0.05). The postoperative limb swelling and postoperative joint mobility did not show statistical significance (P>0.05). Conclusion Application of compressive bandage dressing in TKA surgery is easy to be operate and can reduce perioperative blood loss and allogeneic transfusion incidence.

The discovery of new enzymes for poly(ethylene terephthalate) (PET) degradation has been a hot topic of research globally. Bis-(2-hydroxyethyl) terephthalate (BHET) is an intermediate compound in the degradation of PET and competes with PET for the substrate binding site of the PET-degrading enzyme, thereby inhibiting further degradation of PET. Discovery of new BHET degradation enzymes may contribute to improving the degradation efficiency of PET. In this paper, we discovered a hydrolase gene sle (ID: CP064192.1, 5085270-5086049) from Saccharothrix luteola, which can hydrolyze BHET into mono-(2-hydroxyethyl) terephthalate (MHET) and terephthalic acid (TPA). BHET hydrolase (Sle) was heterologously expressed in Escherichia coli using a recombinant plasmid, and the highest protein expression was achieved at a final concentration of 0.4 mmol/L of isopropyl-β-d-thiogalactoside (IPTG), an induction duration of 12 h and an induction temperature of 20 ℃. The recombinant Sle was purified by nickel affinity chromatography, anion exchange chromatography, and gel filtration chromatography, and its enzymatic properties were also characterized. The optimum temperature and pH of Sle were 35 ℃ and 8.0, and more than 80% of the enzyme activity could be maintained in the range of 25-35 ℃ and pH 7.0-9.0 and Co²⁺ could improve the enzyme activity. Sle belongs to the dienelactone hydrolase (DLH) superfamily and possesses the typical catalytic triad of the family, and the predicted catalytic sites are S129, D175, and H207. Finally, the enzyme was identified as a BHET degrading enzyme by high performance liquid chromatography (HPLC). This study provides a new enzyme resource for the efficient enzymatic degradation of PET plastics.
Actinomycetales/genetics* ; Hydrolases/metabolism* ; Phthalic Acids/chemistry* ; Polyethylene Terephthalates/metabolism*

Hydroxy amino acids, constituents of chiral pharmaceutical intermediates or precursors, have a variety of unique functions in the research fields of biotechnology and molecular biology, i.e. antifungal, antibacterial, antiviral and anticancer properties. Biosynthesis of hydroxy amino acids is preferred because of its high specificity and selectivity. The hydroxylation of hydrophobic amino acids is catalyzed by hydroxylase, which belongs to the mononuclear non-heme Fe(Ⅱ)/α-ketoglutarate-dependent dioxygenases (Fe/αKGDs). Fe/αKGDs utilize an (Fe(Ⅳ)=O) intermediate to activate diverse oxidative transformations with key biological roles in the process of catalytic reaction. Here, we review the physiological properties and synthesis of hydroxy amino acids, especially for the 4-HIL and hydroxyproline. The catalytic mechanism of Fe/αKGDs is elucidated, and the applications of hydroxy amino acids in industrial engineering are also discussed.