Objective:To develop a grading system for necrosis of pedicled flaps in reconstruction of foot and ankle, and to verify its effectiveness and repeatability.Methods:A retrospective observational study was conducted. A total of 40 necroses of foot and ankle pedicled flaps were selected by 2 senior surgeons based on the flap surgery performed by the same surgical group in Department of Orthopaedic Surgery, the 920 Hospital of Joint Logistic Support Force of PLA from January 2010 to January 2022. A grading system for pedicled flap necrosis was proposed by a working group and the 40 necrotic flaps were graded. The coincidence rate was calculated to evaluate the effectiveness of the grading system through correlation studies between grading and clinical treatment. One photo of a typical postoperative necrotic flap was collected from each of the 40 flaps. Then 5 extramural surgeons were asked to grade the necroses shown on the photos according to the proposed grading system. Moreover, weighted Kappa analysis was performed on the results of proposed grading system and also on the standard grading currently in use, to evaluate the repeatability of the proposed grading system. Evaluated data were expressed by Mean±SD, and the coincidence rate was expressed by percentage. The reproducibility was studied by weighted Kappa analysis.Results:Of the 40 necrotic flaps, 7 flaps were classified in Grade I, 16 in Grade Ⅱ, 12 in Grade Ⅲ and 5 in Grade IV. In comparison with the actual treatment methods, the overall coincidence rate of the grading system was 92.5%. It indicated that the proposed grading system could effectively guide the selection of a treatment procedure. The average weighted Kappa coefficient of surgeons was at 0.628 with a 95% confidence interval (95%CI) between 0.460-0.796, which was strongly consistent with the standard of the grading system currently in use.Conclusion:The grading system for necrosis of pedicled flap in reconstruction of foot and ankle proposed in this study is simple and clear. It is able to effectively guide the treatment of flap necrosis. The preliminary validation shows that the classification system has good repeatability.

This study aims to investigate the synergistic antimicrobial effect of demethylzeylasteral meropenem against NDM-1-positive Escherichia coli.Firstly,the nitrocefin hydrolysis assay and molecular docking assay were used to determine the inhibitory effect and mechanism of demethyl-zeylasteral on the hydrolytic activity of the NDM-1 protein.Secondly,the synergistic bacteriostatic effect of demethylzeylasteral with the carbapenem antibiotic meropenem was confirmed by the checkerboard minimum inhibitory concentration assay,growth curve assay,and inhibition zone as-say.The synergistic bactericidal effect of the combination was further determined by the time-kill-ing assay,live/dead bacterial staining assay,and membrane integrity assay.Finally,the G.mellonel-la infection model demonstrated the protective effect of demethylzeylasteral and meropenem.The results indicated that demethylzeylasteral significantly inhibited the hydrolytic activity of NDM-1(IC50=0.32 mg/L)and competitively affected the binding of NDM-1 to meropenem.In vitro tests showed that demethylzeylasteral had good a synergistic antibacterial effect with meropenem and could exert a synergistic bactericidal effect by enhancing the membrane damage of bacteria caused by meropenem.In vivo assays demonstrated that demethylzeylasteral increased the protective effect of meropenem from 67％to 80％.The results obtained in this study provide a therapeutic strategy and antibacterial synergist for treating NDM-1-positive bacterial infections.

Objective:To introduce the concept and procedures of precise flap surgery in construction of knee defects and to report the preliminary clinical outcomes.Methods:The data of 16 patients with knee defects at 17 sides were retrospectively analyzed who had been treated under the guidance of the concept of precise flap surgery at Department of Orthopedic Surgery, The 920th Hospital of Joint Logistic Support Force of PLA from August 2014 to March 2022. There were 12 males and 4 females, aged 44(34, 54) years. The wounds were at the left side in 8 cases, at the right side in 7 ones and at bilateral sides in one, and their sizes ranged from 5 cm×3 cm to 15 cm×11 cm. The time from injury to surgery was 8.5(6.0, 13.0) days. Optimal repair protocols were chosen after the donor and recipient sites were evaluated according to the methods of precise flap surgery: a retrograde anterolateral thigh flap in 7 sides, a descending genicular artery perforator flap in 3 ones, a saphenous artery flap in 2 ones, and a superior genicular lateral artery perforator flap, a popliteal artery perforator flap, a medial sural perforator propeller flap, a peroneal artery perforator propeller flap, and a randomized flap in one, respectively. The flap sizes ranged from 10 cm×6 cm to 15 cm×15 cm. The outcomes and complications of skin flap repair, and functional recovery of the affected limb were recorded.Results:All the flaps at 17 sides survived after surgery; 3 cases developed distal edge necrosis which responded to dressing change. The follow-ups for the 16 patients were 14.5(10.0, 28.0) months. All the flaps presented with good color, texture and contour. Flap bulking, local osteomyelitis, and scar ulcer was found in one case respectively. According to the revascularization assessments in the digital replantation criteria by Hand Surgery Society, Chinese Medical Association, all the flaps at 17 sides were excellent. Accoding to the knee functional evaluation of Hospital for Special Surgery (HSS) at the last follow-up, the 17 affected limbs scored 86(80,91) points, yielding 9 excellent, 7 good and 1 fair sides.Conclusion:Although the defects and donor sites around the knee vary greatly, precise flap surgery may lead to effective control of the variations, choice of an optimal reconstruction protocol, and precise wound repair.

Objective:To investigate the efficacy of digital reconstruction technology in assisted design of lobulated deep inferior epigastric perforator flap (DIEPF) for surgical reconstruction of large defect in lower extremity.Methods:From January 2017 to January 2022, a study was carried out to retrospectively analyse 8 patients who had massive soft tissue defects in lower extremities were admitted in the Department of Orthopaedic Surgery of the 920 Hospital of Joint Logistic Support Force of Chinese PLA. The size of defects varied from 16.0 cm×12.0 cm-28.0 cm×22.0 cm. CTA scans were performed over abdominal aorta and the arteries of lower extremities. Three-dimensional model of DIEPF and vascular pedicles were reconstructed by Mimics software. According to the shape and size of the wound, targeted perforators were determined on the 3D images, and precisely mapped in a digitised rectangular coordinate system. The lobulated flap was then digitally designed in the 3D coordinate system. Flaps were harvested according to preoperative digital designs for the reconstruction of large defects in the lower extremities. The donor site was sutured directly. The flaps and recovery of lower extremities were observed though postoperative follow-ups and were conducted through visits of outpatient clinics and distance interviews via telephone and WeChat. Recoveries of lower extremities were evaluated using Maryland ankle-foot function scoring system.Results:The 3D reconstructed models of the vessels in donor sites were successfully completed for all patients. The harvests of lobulated DIEPF were successfully guided by the digital designs. Fifteen lobes of lobulated DIEPF survived successfully in all 8 patients. All donor sites were closed in the stage-I. Necrosis occurred at the distal tip of a lobulated flap due to a local venous occlusion, and healed after debridement and re-suture. Four patients received further flap debulking surgery. Time of postoperative follow-ups had ranged 15-27 months, with an average of 20 months. At the last follow-up, all the flaps had satisfactory appearance with linear scars at the donor sites. All fractures were healed. Five patients achieved Maryland's ankle-foot function score in excellent, 2 in good, and 1 was acceptable.Conclusion:Digital reconstruction technology can accurately map the perforators and reasonably assist the design of lobulated flaps. A lobulated DIEPF offers a wider area for flap excision and allows a primary closure of the donor sites. Combination of the 2 advantages of a lobulated DIEPF can be effectively applied in reconstruction of a large-sized defect in lower extremity.

Objective:To introduce the methods of retrograde anterolateral thigh flaps in repairing anterior knee joint wounds under the concept of precise flap surgery and to explore the clinical effects.Methods:A retrospective observational study was conducted. From August 2014 to March 2022, 7 patients with anterior knee joint wounds were treated with retrograde anterolateral thigh flap under the guidance of the concept of precise flap surgery in the 920 th Hospital of Joint Logistic Support Force of PLA. Among them, 6 were males and 1 was female, aged 36 to 66 years. The sizes of wounds were 7 cm×5 cm to 15 cm×11 cm after debridement. All the patients were performed with computed tomography angiography (CTA), the donor and recipient sites were evaluated according to the precise flap surgery method, and the optimal pedicle, perforator, and pivot of flaps were chosen. The flap sizes were 10 cm×6 cm to 20 cm×9 cm, and all the donor sites of flaps were sutured directly. The consistency of the intraoperative exploration with preoperative CTA was observed. The flap survival and occurrence of complications were observed after surgery. The color, appearance, texture, and occurrence of complications were followed up. At the last follow-up, the blood supply of flaps was evaluated using the blood circulation evaluation indicators of Chinese Medical Association Hand Surgery Branch's trial criteria for digital replantation function evaluation, and the function of knee joint was evaluated using knee joint scoring system of hospital for special surgery. Results:The flap condition of the intraoperative exploration was completely consistent with that of preoperative CTA. The flaps survived completely after surgery in 6 patients, while necrosis at the edge of the flap occurred in 1 patient, which healed after dressing change. All the flaps were hyperperfused after surgery, and the color of the flaps gradually became normal after 1 week. Follow-up of 7 to 44 months showed that the color, appearance, and texture were well in all the patients, while local osteomyelitis at the proximal tibia occurred in 1 patient. At the last follow-up, all the 7 patients had excellent blood circulation; the function score of knee joint was 69 to 91, which was evaluated as excellent in 3 cases, good in 3 cases, and fair in 1 case.Conclusions:The retrograde anterolateral thigh flap has large variations, and the application of precise flap surgery method can accurately understand the variations before surgery, guide the design and cutting of the flaps, thus achieving precise repair of anterior knee joint wounds, with good repair outcome.

Objective:To introduce the concept and procedure of CTA guided precision flap surgery and report the preliminary clinical application.Methods:The theory of CTA guided precision flap surgery is: based on CTA high-throughput data, comprehensively evaluate the wound and potential donor sites, and select the best plan for wound repair. This article reviews 177 patients treated under the guidance of CTA guided precision flap surgery from August 2014 to December 2018. Among them, 131 were males and 46 were females; they were 7-72 years old, with an average age of 39.5 years. The tissue defects were: 74 cases of foot and ankle, 64 cases of wrist, 15 cases of calf, 11 cases of forearm and upper arm, 7 cases of thigh and perineum, 5 cases of face and neck, and 1 case of abdomen. The size of the defect was 2 cm×1 cm to 65 cm×50 cm. The recipient and donor sites were assessed based on CTA guided precision flap surgery, then choose the optimal flap to repair the defect. The flap types, outcomes and complications were recorded. The visual analogue scale (VAS), British Medical Research Council sensory rating scale, and revascularization assessments of digital replantation standard by Hand Surgery Branch of Chinese Medical Association was used to assess clinical results.Results:All flaps were uneventfully harvested as planned according to the CTA guided precision flap surgery concept.A total number of 181 flaps were harvested, including 125 free flaps and 56 pedicled flaps. The flap area rangedfrom 4 cm×3 cm to 40 cm×8 cm. After surgery, 165 cases were survival completely, 7 cases were total necrosis, 9 cases were partial necrosis. A total of 174 cases of flaps survived. The mean follow-up was 9.2 months (range, 6-60 months). After surgery 53 flaps were bulky, and 7 cases with other complications.At the last follow-up, only 6 patients had mild pain, the VAS score was 1-3. The sensation of the flaps recovered partially. According to the British Medical Research Council sensory rating scale: 68 cases were grade S2 and 106 cases were grade S3. According to the revascularization assessments of digital replantation standard by Hand Surgery Branch of Chinese Medical Association, 171 cases were excellent and 3 cases were good.Conclusion:The concept of precision flap surgery based on CTA can effectively guide flap surgery and achieve precise wound repair.

Objective:To compare the operative treatment and non-operative treatment of the re-ruptured Achilles tendon with rupture end distance within 1 cm.Methods:We retrospectively analyzed 14 cases with Achilles tendon postoperative re-rupture in our hospital from May 2012 to March 2019. All 14 cases showed distance of rupture end less than 1cm during imaging in a passive plantarflexion position. Among the 14 cases with re-rupture, 8 were in the operative treatment group (7 males and 1 female, mean age 36.3±6.4 years, duration from initial rupture to re-rupture 3 to 213 weeks, height 174.9±8.7 cm, weight 75.5±13.9 kg, body mass index 24.5±2.7 kg/m 2, distance of re-ruptured ends 4.9±2.5 mm) and 6 were in the non-operative treatment group (5 males and 1 female, mean age 40.0±9.0 years, duration from initial rupture to re-rupture 4 to 60 weeks, height 173.8±3.5 cm, weight 77.5±7.4 kg, body mass index 25.7±2.5 kg/m 2, distance of re-ruptured ends 5.7±2.1 mm). The Achilles tendon rupture score (ATRS), visual analogue scale (VAS), and foot and ankle ability measure (FAAM) were used to evaluate the result at the patients' last follow-up. Results:All the 14 cases were followed for 8.7 to 92.2 months, with mean follow-up of 39.6 months. Ultrasound or MRI was performed at 6 months postoperatively or at last follow-up to ensure the Achilles tendons' healing. The average ATRS score, VAS score, FAAM-ADL score, and FAAM-Sports score of the operative treatment group were 85.4±13.5, 0 (0, 1.0) , 86.9±8.3, and 76.3±15.4, respectively. While those of the non-operative treatment group were 82.8±5.7, 0.5 (0, 1.3) , 88.1±8.3, and 77.2±15.0, respectively. The average VAS score, FAAM-ADL score, and FAAM-Sports score of the operative treatment group and those of the non-operative treatment group was not significantly different. The ATRS scores of 7 patients of the operative treatment group were between 81 and 96. The satisfaction rate of operative treatment group was 87.5% (7/8). The ATRS scores of 5 patients of the non-operative treatment group were between 81 and 91. The satisfactory rate of non-operative treatment group was 83.3% (5/6). All Achilles tendon re-rupture cases had no complications such as a third time Achilles tendon rupture or wound infection after treatment.Conclusion:For the re-ruptured Achilles tendon with rupture end distance within 1 cm, non-operative treatment achieved similar curative effect compared to operative treatment through extended duration of immobilization and non-weightbearing.

Objective:To measure and compare the geometric rotation axis of the talocrucial joint at different poses during the normal gait.Methods:The kinematic data of 15 healthy volunteers, 8 females, 7 males; age, 26.2±5.4 y (range 19-39 y); height, 170.4±6.9 cm (range 160-183 cm); mass, 65.6±14.0 kg (range 52-100 kg). They were collected using the dual-fluoroscopy technique, and the spatial position of the tibia and talus was determined using the 3D-2D registration method. The medial and lateral side of the trochlear of each talus was fitted by two spheres and the geometric rotation axis of the tibiotalar joint was defined as the line connecting the origins of two spheres. Compared the position and orientation of the axis for different poses during the gait and also compared the difference of the radius of the medial and lateral spheres fitting the trochlear of each talus.Results:The radii of the medial spheres fitting the trochlear of each talus 19.52±1.47 mm,were significantly less than that of the lateral spheres 20.62±1.49 ( t=7.081, P<0.05). The averaged anterior-posterior distance between the geometric rotation point of the tibiotalar joint were 1.54±1.84, 1.71±1.69, 1.70±1.57, 1.72±1.62, 1.80±1.75, 1.96±1.86 mm, respectively, while the averaged medial-lateral distance were 0.06±1.84, -0.03±1.83, 0.08±1.83, 0.10±1.73, 0.10±1.47, 0.09±1.46 mm, respectively, and the averaged superior-inferiordistance were -21.92±1.46, -22.10±1.32, -22.10±1.50, -22.06±1.64, -21.93±1.62, -21.98±1.50 mm, respectively. The averaged angle between the geometric rotation axis of the tibiotalar joint and coronal plane were 3.31°±2.48°, 3.10°±2.67°, 3.64°±2.71°, 3.96°±3.19°, 4.28°±2.82°, 4.16°±3.11°, respectively, while the averaged angle between that and sagittal plane were 84.11°± 2.42°, 83.77°±3.19°, 83.77°±3.45°, 83.81°±3.69°, 83.99°±2.97°, 84.23°±3.01°, respectively, and the averaged angle between that and transverse plane were 4.40°±2.93°, 4.54°±3.74°, 3.97°±3.34°, 3.73°±2.49°, 3.78°±2.76°, 4.48°±2.49°, respectively. The position and orientation of the geometrical rotation axis of the tibiotalar joint at different poses during the gait showed no significant difference ( P>0.05). The rotation axis orientated from laterally and inferiorly to medially and superiorly with an averaged inclination angle from the horizontal plane of 3.74° and an averaged deviation angle from the coronal plane of 4.15°. Conclusion:The geometric rotation axis of the tibiotalar joint was fixed during the gait, therefore fitting the talar trochlea with the two-sphere model with a small radius of the medial sphere and a large radius of the lateral sphere may better mimic the kinematics of tibiotalar joint.

Since its birth in the early 1990s, metabolic engineering technology has gone 30 years rapid development. As one of the preferred chassis for metabolic engineering, S. cerevisiae cells have been engineered into microbial cell factories for the production of a variety of bulk chemicals and novel high value-added bioactive compounds. In recent years, synthetic biology, bioinformatics, machine learning and other technologies have also greatly contributed to the technological development and applications of metabolic engineering. This review summarizes the important technological development for metabolic engineering of S. cerevisiae in the past 30 years. Firstly, classical metabolic engineering tools and strategies were reviewed, followed by reviewing systems metabolic engineering and synthetic biology driven metabolic engineering approaches. The review is concluded with discussing future perspectives for metabolic engineering of S. cerevisiae in the light of state-of-the-art technological development.
Computational Biology ; Metabolic Engineering ; Saccharomyces cerevisiae/genetics* ; Synthetic Biology

Objective: To setup a custom-made gait simulator, and to provide an efficient tool for biomechanics research of ankle and foot. Methods: From November 2017 to April 2018, a total of 6 fresh frozen specimens of the foot and ankle were collected. The donated specimens, free of diseases in the foot and ankle part, were from the Department of Anatomy, Shanghai Medical College of Fudan University. Donors were 3 males and 3 females, aged from 48 to 69 years old, with an average age of 58.8 years old. The nine tendons in the foot were divided into 4 bundles, including anterior group comprised of tibialis anterior (TA), extensor hallucis longus (EHL) and extensor digitorum longus (EDL). Posterior group comprised of Achilles's tendon (AT). Medial group comprised of tibialis posterior (TP), flexor hallucis longus (FHL), and flexor digitorum longus (FDL). Lateral group comprised of peroneus brevis (PB) and peroneus longus (PL). A custom-made gait simulator was set up by using four independent electro motors to actuate 4 bands of tendons in the foot and another six motors to control tibia to achieve 6 degree-freedom parallel mechanism. And a hydraulic machine was used to provide axial pressure along tibia. Gait cycle of six fresh frozen cadaver feet was reproduced using this machine, and the kinematics data of ankle movement and ground reaction force (GRF) data was collected. By comparing the data above with the normal human gait data, the simulation results were analyzed to explore the clinical usage of this machine. Results: On the sagittal plane, the ankle appeared to plantarflexion at the beginning of gait, and then turned to dorsiflexion after the max plantar flexion (about 10°) at 18% of gait cycle. At the 40% gait cycle, ankle joint was in neutral position and reached its max dorsiflexion (about 22°) at 83% gait cycle. On the coronal plane, ankle joint appeared inversion at the beginning and eversion afterwards with 10° range of change. On the horizontal plane, movement of ankle joint was small. Results showed that the first peak of vertical ground reaction force can reach to 1.1-1.3 times of bodyweight at 25% of gait cycle and the second peak appeared little lower at 70% of gait cycle. The GRF in posterior direction reached its peak at 30%, and then turned to anterior with its peak at 83% gait cycle. The GRF had small variation at the internal to external direction.All of the coefficients of multiple correlations (CMC) of GRF and ankle joint movements were close to or greater than 0.90. Conclusion This custom-made gait simulator has good gait simulation ability with high intra repeatability in respect of ankle rotation and ground reaction force, and can satisfy the request for ankle and foot biomechanics research.