Objective: To construct a phenolamine cross-linked coating composed of epigallocatechin gallate(EGCG) and poly-L-lysine(PLL) on the surface of the porous pure Ti integrated with the antibacterial substance chlorhexidine(CHX), and to study the antibacterial property and biosafety. Methods: A porous structure(pTi group) was formed on the surface of titanium samples by alkaline heat treatment. Then the pTi group was immersed in the mixed solution of EGCG and PLL in an alkaline aerobic environment for 24 h to obtain the phenolamine group samples(EP group). Finally, the titanium tablets were further immersed in the aqueous solution of chlorhexidine(CHX) for 24 h to obtain the antibacterial groups(EPC group). Microstructure and properties of the surface were characterized by scanning electron microscopy(SEM), X-ray photoelectron spectrometer(XPS) and water contact angle measuring instrument. The antibacterial properties of coating were observed and evaluated by nephelometry, inhibition zone method and live/dead bacterial staining. The cytocompatibility of the coating was evaluated by MTT method and cell fluorescence staining, and the cell adhesion and proliferation ability in bacterial environment were evaluated by the co-culture of bacteria and cells. Results: SEM results showed that the pore size of samples after alkali heat treatment decreased with the deposition of the phenolamine coating. The measurement of water contact angle showed that the contact angle increased significantly with the grafting of coating. The intensity of N1s and C1s peaks increased and Ti2p and O1s peaks decreased detected by XPS tests. The Cl2p peak appeared in EPC group referred to the control group. The antibacterial experimentsin vitroshowed that the antibacterial samples could perform effective antibacterial effects on Staphylococcus aureus and Aggregatibacter actinomycetem-comitans for at least 7 days. In the biocompatibility experiments, MTT and cell fluorescence staining results showed that the adherent cells had good morphology and proliferative activity. The bacteria-cell co-culture results showed that the EPC groups could provide a good environment for cell proliferation and growth with excellent antibacterial properties. Conclusion Chlorhexidine-grafted phenolamine deposited on porous titanium surface displays an effective antibacterial effect with good biosafety performance, which can play an antibacterial role in the bacterial environment while ensuring cell adhesion and proliferation.

The synthesis of fine chemicals using multi-enzyme cascade reactions is a recent hot research topic in the field of biocatalysis. The traditional chemical synthesis methods were replaced by constructing in vitro multi-enzyme cascades, then the green synthesis of a variety of bifunctional chemicals can be achieved. This article summarizes the construction strategies of different types of multi-enzyme cascade reactions and their characteristics. In addition, the general methods for recruiting enzymes used in cascade reactions, as well as the regeneration of coenzyme such as NAD(P)H or ATP and their application in multi-enzyme cascade reactions are summarized. Finally, we illustrate the application of multi-enzyme cascades in the synthesis of six bifunctional chemicals, including ω-amino fatty acids, alkyl lactams, α, ω-dicarboxylic acids, α, ω-diamines, α, ω-diols, and ω-amino alcohols.
Amino Acids ; Biocatalysis ; Amino Alcohols ; Coenzymes/metabolism* ; Diamines

Industrial enzymes have become the core "chip" for bio-manufacturing technology. Design and development of novel and efficient enzymes is the key to the development of industrial biotechnology. The scientific basis for the innovative design of industrial catalysts is an in-depth analysis of the structure-activity relationship between enzymes and substrates, as well as their regulatory mechanisms. With the development of bioinformatics and computational technology, the catalytic mechanism of the enzyme can be solved by various calculation methods. Subsequently, the specific regions of the structure can be rationally reconstructed to improve the catalytic performance, which will further promote the industrial application of the target enzyme. Computational simulation and rational design based on the analysis of the structure-activity relationship have become the crucial technology for the preparation of high-efficiency industrial enzymes. This review provides a brief introduction and discussion on various calculation methods and design strategies as well as future trends.
Biocatalysis ; Biotechnology ; Enzymes ; chemistry ; metabolism ; Metabolic Engineering ; Protein Engineering ; Structure-Activity Relationship

Objective: To evaluate the efficacy of gastric pull-up and complex laryngotracheal flap in reconstruction for circumferencial defects after resection of hypopharyngeal and cervical esophageal cancers. Methods: A total of 163 cases (152 males, 11 females) with circumferencial defect after resection of hypopharyngeal and cervical esophageal cancers received reconstructive surgeries by gastric pull-up (42 cases) and complex laryngo-tracheal flaps (121 cases), of them 115 cases simultaneously underwent unilateral neck dissection and 20 cases had bilateral neck dissection. Postoperative radiotherapy was used in 67 cases, with a dosage of 40-60 Gy. Results: There were 127 (77.9%) cases with positive metastatic lymph nodes. Of 42 patients with gastric pull-up reconstruction, 39 cases (92.8%) recovered the function of oral swallowing after operation, and 8 cases with cervical esophageal cancer recovered the functions of oral swallowing and speech after gastroesophageal anastomosis reconstruction. There were 3 (7.1%) cases died of surgery and 8 cases with surgical complications. Reconstruction of upper digestive tract with combined laryngotracheal flap was successful in all 121 cases, with recovered oral swallowing function after operation. No patient died of surgery but 24 cases had complications, mainly pharynx skin fistula or wound infection, which were cured by conservative treatments. The 1-, 3- and 5-year survival rates for 163 patients were 69.8%, 50.5% and 34.3%, respectively. The independent factors for prognosis included T4 (P<0.001) and N+ (P=0.042). Conclusions The complex of laryngotracheal flap with pectoralis major myocutaneous flap is suitable for most advanced hypopharyngeal cancer after resection of the tumor and reconstruction of circumferencial defect. It is simple technology, low and slight complication rate. The minority is not suitable for the application of pectoralis major myocutaneous flap can be used instead of free anterolateral thigh flap. Gastric pull-up for reconstruction of upper digestive tract is suitable for most patients with cervical esophageal cancer and hypopharyngeal carcinoma invading the cervical esophagus who are not suitable for laryngotracheal flap reconstruction, with good swallowing function after surgery. However, it is prudent to choose operative indications because of serious surgical trauma and risks for complications.

Racemases have been applied for the synthesis of enantiomerically pure compounds through the deracemization methods. Mandelate racemase from Pseudomonas putida was the only enzyme that catalyzes the interconversion of mandelate enantiomers. Using genome mining approaches, we identified 9 mandelate racemases (MRs). A novel racemase named ArMR with higher activity and better soluble protein expression, was isolated from Agrobacterium radiobacter. ArMR displayed the optimum catalytic activity at 50 ℃, pH 7.8 in Tris-HCl buffer. The half-life of ArMR at 50, 40 and 30 ℃ was 0.17, 27.2 and 70.7 h, respectively. KM parameter of ArMR towards (R)- and (S)-mandelic acid was 1.44 and 0.81 mmol/L, respectively; the corresponding kcat value was 410 s⁻¹ and 218 s⁻¹. In addition, KM of ArMR towards (R)- and (S)-2-chloro mandelic acid was 6.48 and 6.37 mmol/L, and the corresponding kcat value 0.22 s⁻¹ and 0.23 s⁻¹, respectively. Meanwhile, Mg²⁺ and Mn²⁺ could activate the enzyme whereas Zn²⁺ inactivated the enzyme completely. Discovery of more novel MRs provides supports further research and development of these racemases.

Objective To study the clinical effect of diversion treatment for complex anal fistula.Methods A total of 60 patients with complex anal fistula were enrolled in this study were divided into control group and experimental group according to the random number table method,with 30 cases per group.All patients were given routinely imaging examination and other related checks,and the intestine tract was cleaned in the morning of the operative day.The control group were treated with low anal fistula resection,while the experimental group with diversion treatment.The efficacy of treatment,postoperative anal function,wound healing time and pain were compared between the two groups.Results The total effective rate in the experimental group was higher than that in the control group (P ＜ 0.05).The Wexner score of the anus function in the experimental group was lower than that in the control group at 1,7,14 and 21 d after the operation,and the differences were statistically significant (P ＜ 0.05).The wound healing time,VAS score on 14thpostoperative day,intraoperative wound area and postoperative scar size were lower in the experimental group than that in the control group (P ＜ 0.05).Conclusion Diversion treatment for complex anal fistula has significant efficacy,faster postoperative wound healing,and it can effectively relieve clinical symptoms and signs,improve anal function,reduce body pain,so it is worthy of clinical promotion.

Objective To study the clinical effect of diversion treatment for complex anal fistula.Methods A total of 60 patients with complex anal fistula were enrolled in this study were divided into control group and experimental group according to the random number table method,with 30 cases per group.All patients were given routinely imaging examination and other related checks,and the intestine tract was cleaned in the morning of the operative day.The control group were treated with low anal fistula resection,while the experimental group with diversion treatment.The efficacy of treatment,postoperative anal function,wound healing time and pain were compared between the two groups.Results The total effective rate in the experimental group was higher than that in the control group (P ＜ 0.05).The Wexner score of the anus function in the experimental group was lower than that in the control group at 1,7,14 and 21 d after the operation,and the differences were statistically significant (P ＜ 0.05).The wound healing time,VAS score on 14thpostoperative day,intraoperative wound area and postoperative scar size were lower in the experimental group than that in the control group (P ＜ 0.05).Conclusion Diversion treatment for complex anal fistula has significant efficacy,faster postoperative wound healing,and it can effectively relieve clinical symptoms and signs,improve anal function,reduce body pain,so it is worthy of clinical promotion.

OBJECTIVE:To provide reference for reasonable and safe use of drugs in children. METHODS:580 prescription drug instructions of chemical drugs and chemical product for treatment were collected from our hospital. Children information stated in drug instruction of exclusive drugs for children and special drugs,and in dosage and usage,clinical trial,pharmacokinetics and other items were all analyzed statistically ratio analysis and sequence analysis. RESULTS:The exclusive drugs for children were few,and major dosage form were injection. The instruction of special drugs were lack of children’s information. Usage and dosage based on monotonous evidence. The pharmacokinetic parameters were incomplete,and there were slender amount of data about chil-dren clinical trials. CONCLUSIONS:The drug instruction of drugs for children are looking blue. It is urgent to standard drug in-struction and complete medication information for children,so as to ensure safe and effective of drug use.