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Purpose Piezosurgery has been used widely in oral and maxillofacial surgery, but there has been no report systematically describing an osteotomy method with piezosurgery for complicated mandibular third molar removal. The aim of this study was to introduce 4 osteotomy methods using piezosurgery and evaluate their effects. Materials and Methods A retrospective study was conducted of patients with a complicated impacted mandibular third molar requiring extraction. The predictor variable was the extraction technique. Four osteotomy methods using piezosurgery were tested according to different impaction types: method 1 involved complete bone removal; method 2 involved segmental bone removal; method 3 involved bone removal combined with tooth splitting; and method 4 involved block bone removal. Outcome variables were success rate, operative time, major complications (including nerve injury, mandible fracture, severe hematoma, or severe edema), and serious pyogenic infection. Data were analyzed using descriptive statistics. Results The study was composed of 55 patients with 74 complicated impacted mandibular third molars. All impacted mandibular third molars were removed successfully. The average surgical time was 15 minutes (range, 8 to 26 minutes). Thirty-eight molars (51.4%) were extracted by method 1, 18 molars (24.3%) by method 2, 12 molars (16.2%) by method 3, and 6 molars (8.1%) by method 4. Two cases (2.7%) developed postoperative infections and recovered within 1 week using drainage and antibiotic administration. Conclusion The 4 osteotomy methods with piezosurgery provide effective ways of removing complicated impacted mandibular third molars. [ABSTRACT FROM AUTHOR]

Abstract: The bond selective hydrolysis of glycyrrhizin (GL) to glycyrrhetic acid 3-O-mono-β-d-glucuronide (GAMG) catalyzed by recombinant β-d-glucuronidase from Escherichia coli BL21 (PGUS-E) was successfully performed in an ionic liquid (IL)/buffer biphasic system. Five ILs were analyzed, however, a hydrophobic IL 1-butyl-3-methylimidazolium hexafluorophosphate ([BMIM]PF6) showed the best biocompatibility with PGUS-E. An obvious enhancement in the initial reaction rate, substrate conversion, GAMG yield and chemical bond selectivity (S cb) was observed using 40% (v/v) [BMIM]PF6/buffer as the reaction medium when compared to the acetate buffer medium. Under the optimized conditions (pH 6.0, temperature 50°C, substrate concentration 6mM and shaking speed 200rpm), the initial reaction rate, the GAMG yield and the S cb reached 3.15mMh−1, 74.36% and 98.12%, respectively. The recyclability of [BMIM]PF6 was also studied and found to be reusable for five batches with high recovery percentage (≥92%). Furthermore, the desired product and byproduct were easily separated since they were distributed in different phases. Additionally, higher V max (3.14 versus 2.24mMh−1), lower apparent K m (1.21 versus 1.80mM) and E a (25.97 versus 32.60kJmol−1) were achieved in [BMIM]PF6/buffer biphasic system than that in monophasic buffer system. [ABSTRACT FROM AUTHOR]

Abstract: Hydrolysis of glycyrrhizin (GL) to glycyrrhetic acid 3-O-mono-β-d-glucuronide (GAMG) by whole-cell biocatalysts in a system containing non-conventional solvents was performed. Three whole-cell biocatalysts were used, including wild-type Penicillium purpurogenum Li-3 (w-PGUS) and recombinant strains Escherichia coli BL21 and Pichia pastoris GS115. The biotransformation of GL to GAMG by w-PGUS in a 1-butyl-3-methylimidazolium hexafluorophosphate ([Bmim]PF6)/buffer biphasic system was the main focus of this study because w-PGUS showed a higher GAMG yield and a higher relative activity in this system than the other two whole-cell biocatalysts. Using the optimized reaction conditions determined as a pH 5.2 buffer, a 6.0mM substrate concentration, a reaction temperature of 30°C, and a 60g/L (1.23U/g) cell concentration, a GAMG yield of 87.63% was achieved after 60h. After eight reaction cycles, [Bmim]PF6 retained a high recovery percentage (85.48%)[0], indicating the reusability of this IL. The biotransformation activity of w-PGUS was not significantly affected, even after two batch reaction cycles. Furthermore, the product GAMG and the byproduct glycyrrhetinic acid were spontaneously separated in the biphasic system. In conclusion, the combination of whole cells and ionic liquid is a promising approach for economical and industrial-scale production of GAMG. [Copyright &y& Elsevier]