Objective To investigate the effect of transition between hypoxia and normoxia on proliferation of rabbit mesenchymal stem cells(rMSCs).Methods rMSCs expanded in hypoxia were divided into two groups:L-L group and L-N group.Moreover,rMSCs expanded in normoxia were also divided into two groups:N-N group and N-L group.The L-L and N-L groups were subsequently subcultured in hypoxia,and L-N and N-N groups in normoxia.Growth curve,colony-forming efficiency,glucose and lactate metabolism,and intracellular ROS generation of the four groups were examined.Results In L-L group cell density and colony-forming efficiency were the highest,and intracellular ROS generation was the lowest,whereas reversed results were obtained in N-N group.Cells cultured in hypoxic conditions exhibited higher glucose consumption,lactate production and yield coefficients of lactate from glucose compared to normoxic ones.Conclusion Hypoxia may enhance the proliferation of rMSCs in continuous subcultures.There is a potential link between intracellular ROS generation and expansion of rMSCs.

BACKGROUND:Peripheral nerve injury is a common disease in clinic, which severely affects the patients' quality of life. How to promote peripheral nerve regeneration is an issue of concern.OBJECTIVE:To study the effect of modified rabbit defensin 1 on peripheral nerve regeneration and functional recovery. METHODS: Eighteen Sprague-Dawley rats were randomly divided into three groups. The rat sciatic nerves were transected and bridged by biodegenerated chitin conduits, followed by the injection of neurotrophic factor (group 1), modified rabbit defensin 1 (group 2) and normal saline (control group) into the gluteus, respectively, for consecutive 7 days. RESULTS AND CONCLUSION: The sciatic nerve function index in the groups 1 and 2 was higher than that in the control group at 4 weeks postoperatively. The order of motor nerve conductive velocity was as follows: group 1 > group 2 > control group. The diameter regenerated fibers and axons, and the myelin thickness in the group 2 were less than those in the group 1, but were more than those in the control group. These results indicate that the modified rabbit defensin 1 can promote peripheral nerve regeneration, which may be related with the clearance of residual myelin by macrophages and the improvement in nerve regeneration environment.

Objective To shorten the transfer time of critical inpatients from wards to intensive care unit (ICU). Methods From Novem-ber to December, 2015, 30 critical inpatients transferred from wards to ICU were investigated, and analyzed with Six Sigma DMAIC five-step method. There were 7 main processes and 22 sub-processes refined in transfer procedure, as well as the key quality points and the factors influencing the safety of transferring. Some improvement advice were recommended, including multifunctional transfer cart, Check-list before Transfer to Intensive Care Unit for Critical Patients, setting up transport group, training for young nurses and application of SBAR communication. Other 30 critical inpatients transferred from wards to ICU, from May to June, 2016, after the series of control pro-grams, were investigated. Results After improvement, the total transfer time from wards to ICU decreased (t=15.052, P<0.001), without the increase of human power and unsafety issues. The rescue success rate increased from 91.67%to 98.01%. Conclusion The process transfer-ring patient from wards to ICU has been reengineered based on Six Sigma DMAIC management, that reduces the time and improve the res-cue success rate.

BACKGROUND:In an additional changing magnetic field, magnetosomes can invade the tumor cells and inhibit their proliferation.OBJECTIVE: To study the effect of targeted delivery of pHSP70-shPLK1/DOX compounds with magnetosome of magnetotactic bacteria on the treatment of osteosarcoma.METHODS: Human osteosarcoma cell U2OS was divided into four groups: group A: magnetosomes of magnetotactic bacteria+pHSP70-shPLK1/DOX complex; group B: magnetosomes of magnetotactic bacteria; group C: magnetosomes of magnetotactic bacteria+pHSP70-shPLK1/DOX complex, combined with magnetic intervention; group D: magnetosomes of magnetotactic bacteria, combined with magnetic intervention. After 12, 24, 48 and 72 hours of culture, the uptake rate of osteosarcoma cells was observed; cell cycle was evaluated by flow cytometry; PLK1 mRNA and protein expression levels were detected by RT-PCR and western blot, respectively; cell proliferation was explored by MTT assay; cell adhesion and invasion were checked by adhesion assay and Transwel chamber assay, respectively; and the apoptosis rate was measured by apoptosis detection Kit.RESULTS AND CONCLUSION: (1) After culture of 12 and 24 hours, the uptake rate was the highest in group D; meanwhile, the uptake rate was the highest in group B after 48 and 72 hours of culture. (2) The ratio of G2/M phase decreased and the ratio of G0/G1 increased gradualy in group A, group C and group D; the G2/M phase ratio of C group was the lowest at each time point, followed by group D, and that of group A was the highest; and the G2/M phase ratio increased gradualy in group B. (3) Folowing 12 and 24 hours of culture, the expression of PLK1 in group B and group D was higher than that in group A and group C (P < 0.05); in addition, the expression of PLK1 in group B was higher than that in the other three groups after 48 and 72 hours of culture (P < 0.05), and the PLK1 level in group D was higher than that in group A and group C (P < 0.05). (4) The proliferation, adhesion and invasion ability in group B were the highest at different time points, but the apoptosis rate was the lowest. Furthermore, the proliferation, adhesion and invasion abilities in group C were the lowest at different time points, and the apoptosis rate was the highest. To conclude, our experimental results show that the targeted delivery of pHSP70-shPLK1/DOX complex by magnetosomes of magnetotactic bacteria can enhance the apoptosis of osteosarcoma cells and inhibit their proliferation and invasion.

BACKGROUND:Positioning of the distal locking screws of a tibial intramedulary nail is often chalenging and time consuming. The traditional free-hand technique under fluoroscopic control involves considerable radiation exposure.OBJECTIVE: To evaluate the results of a new electromagnetic navigation system (TRIGEN-SURESHOT navigation system) for distal locking of tibial intramedullary nail in tibial diaphyseal fracture and to compare the effects with the free-hand method.METHODS: Forty-five cases of tibial diaphyseal fracture in the Second Hospital of Anhui Medical University from May 2014 to August 2015 were analyzed retrospectively, and were divided into two groups. Patients in navigation group (n=23) were treated with intramedullary nail using the TRIGEN-SURESHOT navigation system for distal locking, and the remainings in free-hand group (n=22) were given the free-hand method.RESULTS AND CONCLUSION: All cases were followed up for 17-32 months. The one-time success rate of distal locking nail operation was 100％ in the navigation group, which was significantly higher than that in the free-hand group (P < 0.05). The locking nail time in the navigation group was significantly less than that in the free-hand group (P < 0.05).No significant differences were found in the incidence of adverse events and fracture healing time between two groups (P > 0.05). To conclude, the effect of the TRIGEN-SURESHOT navigation system for distal locking of tibial intramedullary nail is satisfactory, exhibiting the advantages of short operation time, high success rate, and no radiation.

Objective:To investigate the application of combined distractor in the treatment of refractory distal radius fractures.Methods:From March 2018 to February 2020, the data of 32 patients with refractory distal radius fractures treated with combined distractor-assisted reduction were retrospectively analyzed. The propensity score matching method was used to establish a non-distractor group according to 1∶1 matching, with a total of 32 patients. In the distractor group, there were 15 males and 17 females, age 54.9 ±15.8 years (range, 18-77). According to AO classification, 3 cases were A3, 3 cases were B3, 16 cases were C2, 10 cases were C3. In the non-distractor group, there were 12 males and 20 females, age 59.7±14.8 years, 4 cases were A3, 5 cases were B3, 12 cases were C2 and 11 cases were C3. Main measures: surgical time, radial height, palm inclination, ulnar deviation, range of motion of the wrist, visual analogue scale (VAS), and functional assessment using disability of arm, shoulder and hand (DASH) and modified Mayo wrist score (MMWS).Results:A total of 64 patients were included in this study, and all patients successfully completed the operation and were followed up for 12-54 months, with an average of 17.8 months. The operative time of the distractor group was 91.2±14.6 min, which was significantly lower than that of the non-distractor group 137.6±27.3 min, and the difference was statistically significant ( t=8.48, P<0.001); the radial height in the distractor group 11.5±1.4 mm was significantly higher than that in the non-distractor group 10.6±1.3 mm, and the difference was statistically significant ( t=2.59, P=0.012). At the last follow-up, there were no statistically significant differences in the palm inclination 7.9°±4.4° vs. 7.5°±3.5°, ulnar deviation 23.3°±5.7° vs. 22.3°±4.5°, wrist flexion 63.2°±15.3° vs. 62.6°±11.1°, dorsiflexion 63.5°±10.7° vs. 62.4°±15.2°, pronation 69.2°±11.8° vs. 67.0°±11.0°, supination 73.1°±10.4° vs. 72.0°±8.7°, VAS 0.8±0.5 points vs. 0.9±0.7 points, DASH score 12.9±6.6 points vs. 13.4±7.0 points amd MMWS 84.1±5.8 points vs. 83.5±6.2 points ( P>0.05). One patient in the distractor group had symptoms of extensor muscle irritation, and the symptoms disappeared after the internal fixation was removed; 2 patients in the non-spreader group developed carpal tunnel syndrome, which improved after incision and decompression treatment. Conclusion:For refractory distal radius fractures, the use of combined distractor can achieve better radius height recovery and shorten the operation time, and has a satisfactory postoperative effect.

Objective To propose a concept of irreducible tibial shaft fractures and to discuss their imaging characteristics and clinical significance.Methods A retrospective study was performed in 21 patients with tibial shaft fracture who had received intraoperative intramedullary nailing after limited open reduction at Department of Orthopaedics,The Second Affiliated Hospital to Anhui Medical University from November 2013 to June 2018.They were 14 males and 7 females,aged from 21 to 66 years (average,34.9 years).There were 15 left and 6 right sides.Firstly,closed reduction was performed followed by traction,folding and rotation,but repeated attempts failed to achieve smooth reduction or insertion of guide wire.Next,local limited open reduction had to be performed for intramedullary nailing.The X-ray and CT images of the tibial fractures were collected to analyze their imaging characteristics.The imaging manifestations were characterized into 4 types:single-segment type with intact fibula,multiple-segment type,interlocking type where the distal and proximal ends interlock commonly seen in short spiral and short oblique fractures,and incarceration type where the fracture interspace is blocked by a bone fragment.The therapeutic efficacy was evaluated at the final follow-up by knee scores of The Hospital for Special Surgery (HSS) and Kofoed ankle scores.Results Of the 21 patients,2 were single-segment type,4 multiple-segment type,13 interlocking type and 2 incarceration type.They were followed up for 7 to 50 months (average,22.7 months).The fractures united after 5 to 16 months (average,7.3 months).Postoperative knee pain was observed in 3 cases and delayed fracture union in 2.Osteomyelitis,superficial wound infection,implant breakage or malunion occurred in none of the patients.The therapeutic efficacy evaluated at the final follow-up by HSS knee scores and Kofoed ankle scores revealed 15 excellent,4 good and 2 fair cases,yielding an excellent to good rate of 90.5％.Conclusion The concept of irreducible tibial shaft fractures may lead to preoperative awareness on the part of the surgeons so that ineffective repeated reductions can be spared and the damage to the blood supply to the fracture ends and the operation time can be reduced.

Objective:To explore the short-term therapeutic outcomes of femoral neck fractures fixated by Femoral Neck System (FNS).Methods:A retrospective analysis was conducted of the 16 patients with femoral neck fracture who had been admitted to the Department of Traumatology & Orthopedics, The Second Affiliated Hospital to Anhui Medical University from January to December 2019. They were 6 males and 10 females, aged from 24 to 69 years (average, 47.5 years). According to the Garden Classification, there were 3 cases of type Ⅱ, 7 cases of type Ⅲ, and 6 cases of type Ⅳ. All the 16 patients were fixated with FNS. Recorded were operation time, frequency of intraoperative fluoroscopy, intraoperative blood loss, quality of postoperative fracture reduction, hospital stay, fracture healing time, and efficacy and complications at the last follow-up.Results:The 16 patients were followed up for 5 to 16 months after operation (average, 9.3 months). According to the Garden indexes, fracture reduction was evaluated as satisfactory in all the 16 patients. The operation time in this group ranged from 25 to 115 min with an average of 41.5 min, the frequency of intraoperative fluoroscopy from 14 to 47 times with an average of 26 times, the intraoperative blood loss from 35 to 210 mL with an average of 76 mL, the hospital stay from 3 to 9 days with an average of 4.6 days, and the fracture healing time from 3 to 6 months with an average of 4.5 months. By the Harris hip scores at the last follow-up, the function of the affected hip was rated as excellent in 10 cases, good in 5 and fair in one. Follow-ups revealed no complications like infection or implant loosening.Conclusions:The FNS is a new type of simple, reliable, safe and minimally invasive internal fixation for the treatment of femoral neck fractures. The plate, bolt, anti-rotation screws and locking screws in FNS can be inserted through a single minimally invasive incision, leading to reliable fixation, limited irritation to the lateral muscular soft tissues, and fine short-term outcomes.

Objective:To compare of the efficacy of Steinman pin-assisted and manual reduction for the treatment of distal femoral fracture with anterograde intramedullary nail.Methods:From January 2014 to August 2018, data of 54 patients with distal femoral fracture were retrospectively analyzed. According to the fracture reduction methods, patients were divided into two groups: bare-handed reduction group and Steinman pin-assisted reduction group (referred to Steinman pin group). There were 16 males and 10 females in bare-handed reduction group, with age of 37.5±9.2 years (range, 21-59 years). According to AO/OTA classification, 16 cases were type 32-A, 7 type 32-B, 3 type 32-C. There were 19 males and 9 females in Steinman pin reduction group, with age of 36.4±9.8 years (range, 18-55 years). According to AO/OTA classification, 19 cases were type 32-A, 7 type 32-B, 2 type 32-C. The reduction time, fluoroscopy times, intraoperative blood loss, fracture healing time, and knee joint function score of American hospital for special surgery (HSS) were compared between the two groups.Results:The amount of blood loss during operation was 142.78±29.76 ml in the bare-handed group, and 94.81±17.71 ml in the Steinman pin group. The reduction time of fracture was 14.19±2.50 min in the bare-handed group and 5.02±1.69 min in the Steinman pin group. The times of fluoroscopy during reduction was 12.56 ±2.01 in the bare-handed group and 5.01±1.51 in the Steinman pin group. There were significant differences in the above indexes ( t=12.19, 4.02, 5.47; all P < 0.05). All 54 patients were followed up for 12-51 months, with an average of 23.4 months. All the fractures healed, and there was no delayed union or nonunion. The healing time was 7.01±1.15 months in the bare-handed group and 5.99±0.97 months in the Steinman pin group. There were no significant difference. The HSS score of knee joint function was 23.7±4.1 before operation, 61.3±4.5 at 1 month after operation, 70.2±4.2 at 2 months after operation, 78.9±5.9 at 3 months after operation, 87.9±4.6 at 6 months after operation, and 93.1±5.8 at 12 months after operation, in the bare-handed group. Meanwhile, in the Steinman pin group, 22.5±3.8 before operation, 62.2±5.1 at 1 month after operation, 69.1±4.7 at 2 months after operation, 79.2±4.3 at 3 months after operation, 88.6±5.3 at 6 months after operation, and 92.3±6.1 at 12 months after operation. There were no significant difference between the two groups ( t=1.113, 0.689, 0.908, 0.212, 0.519, 0.494, P > 0.05). There were significant differences between the two groups at each time point before and after operation ( F=716.42, 815.52, P < 0.001). There were no complications such as injection point infection, vascular and nerve injury, failure of internal fixation and so on. Conclusion:Both groups had good functional recovery after operation. However, compared with bare-handed reduction, Steinman pin groupreduction has less intraoperative blood loss, shorter reduction time and less fluoroscopy times, which is a safer reduction method.

Objective:To evaluate the trauma center model in general hospitals for patients with severe trauma.Methods:The data of 1,248 patients with severe trauma (ISS≥16) were retrospectively analyzed who had been admitted to the trauma centers in 6 Chinese general hospitals from January 2019 through June 2020. They were 987 males and 261 females with an age of 50.4 years ± 15.4 years. Their injuries were caused by a traffic accident in 622 cases, falling from a height in 357 cases, a knife in 62 cases, and others (like a heavy object and fall) in 207 cases. Upon admission, their injury severity scores (ISS) were 24.9±8.5 and their Glasgow coma scores (GCS) 12.6±3.6. They were all treated in a scientific and standard manner by a multidisciplinary team at the trauma center of their specific general hospital. Recorded were deaths within 30 days after admission, 30-day mortality and causes of death.Results:All the patients were treated effectively. 101 deaths occurred within 30 days after admission, yielding a 30-day mortality of 8.1%. The main causes of death were severe craniocerebral injury in 56 cases, hemorrhagic shock in 26 cases, multi-organ failure in 11 cases and others in 8 cases.Conclusions:Establishment of trauma centers in China can make up for the disadvantage of over-division of clinical specialties in large general hospitals which has led to insufficient care for patients with severe trauma and multiple injuries. The trauma centers in general hospitals may be a feasible model to be popularized in treatment of patients with severe trauma and multiple injuries.