Repression of LSD1 potentiates homologous recombination-proficient ovarian cancer to PARP inhibitors through down-regulation of BRCA1/2 and RAD51.

Poly (ADP-ribose) polymerase inhibitors (PARPi) are selectively active in ovarian cancer (OC) with homologous recombination (HR) deficiency (HRD) caused by mutations in BRCA1/2 and other DNA repair pathway members. We sought molecular targeted therapy that induce HRD in HR-proficient cells to induce synthetic lethality with PARPi and extend the utility of PARPi. Here, we demonstrate that lysine-specific demethylase 1 (LSD1) is an important regulator for OC. Importantly, genetic depletion or pharmacological inhibition of LSD1 induces HRD and sensitizes HR-proficient OC cells to PARPi in vitro and in multiple in vivo models. Mechanistically, LSD1 inhibition directly impairs transcription of BRCA1/2 and RAD51, three genes essential for HR, dependently of its canonical demethylase function. Collectively, our work indicates combination with LSD1 inhibitor could greatly expand the utility of PARPi to patients with HR-proficient tumor, warranting assessment in human clinical trials.

[Modified internal fixator combined with sacroiliac screws in treatment of Tile C1.3 pelvic fracture].

Objective: To investigate the effectiveness of modified internal fixator (INFIX) to fix the anterior pelvic ring for Tile C1.3 pelvic fracture by comparing with the traditional INFIX. Methods: The patients with Tile C1.3 pelvic fractures admitted between April 2018 and June 2021 were taken as the study objects. Of them, 55 cases were included in the study according to the selection criteria. During operation, the anterior pelvic ring was fixed with the modified INFIX in 30 cases (modified group) and with the traditional INFIX in 25 cases (control group). The posterior pelvic ring in 55 cases was fixed with sacroiliac screws. There was no significant difference between the two groups in gender, age, cause of injury, time from injury to operation, and combined injury ( P>0.05). The operation time, intraoperative blood loss, and complications were recorded and compared between the two groups. The X-ray film was taken to evaluate the reduction of the anterior pelvic ring after operation, grade the reduction according to the Matta scoring standards, and observe the fracture healing and healing time. The function was evaluated according to Majeed scoring standards during follow-up. Results: The operation time of the modified group was significantly longer than that of the control group ( Z=-3.837, P<0.001), but there was no significant difference in the intraoperative blood loss between the two groups ( t=-1.831, P=0.076). All patients were followed up 12-18 months (mean, 14 months). X-ray film reexamination showed that the excellent and good rate of Matta scoring for anterior pelvic ring reduction in the modified group was 88.00%, which was significantly better than that in the control group (63.33%) ( χ 2=4.373, P=0.037). All fractures healed, and the fracture healing time of the modified group and the control group was (12.04±3.59) and (14.83±4.83) weeks respectively, with a significant difference ( t=2.401, P=0.020). At last follow-up, the excellent and good rates of Majeed scoring were 80.00% in the modified group and 76.67% in the control group, with no significant difference ( χ 2=0.089, P=0.766). In the modified group, 2 cases (8%) had complications, all of which were incision infection above pubic symphysis. In the control group, 9 cases (30%) had complications, including 5 cases of lateral femoral cutaneous nerve injury, 2 cases of femoral nerve paralysis, and 2 cases of delayed fracture healing. The incidence of complications was significantly lower in the modified group than in the control group ( χ 2=4.125, P=0.042). Conclusion: Compared with the traditional INFIX, the modified INFIX to fix the anterior pelvic ring for Tile C1.3 pelvic fracture has fewer complications, better stability, shorter fracture healing time, and lower risk of nerve injury.

[Current status and progress of locking plate in the treatment of distal femoral comminuted fracture].

OBJECTIVE: To review the current status and progress of locking plate for the treatment of distal femoral comminuted fractures. METHODS: The related literature was extensively reviewed to summarize the current status and progress in the treatment of distal femoral comminuted fracture with locking plate from four aspects: the current treatment situation, the shortcomings of locking plate and countermeasures, the progress of locking technology, locking plate and digital orthopedic technology. RESULTS: Treatment of distal femoral comminuted fractures is challenging. Locking plates, the most commonly used fixation for distal femoral comminuted fractures, still face a high rate of treatment failure. Double plates can improve the mechanical stability of comminuted fractures, but specific quantitative criteria are still lacking for when to choose double plates for fixation. The far cortial locking screw has shown good application value in improving the micro-movement and promoting the growth of callus. The biphasic plating is a development of the traditional locking plate, but needs further clinical examination. As an auxiliary means, digital orthopedic technology shows a good application prospect. CONCLUSION: The inherent defect of locking plate is a factor that affects the prognosis of distal femoral comminuted fracture. The optimization of locking technology combined with digital orthopedic technology is expected to reduce the failure rate of treatment of distal femoral comminuted fracture.

[Research on the nature of micromovement and the biomechanical staging of fracture healing].

OBJECTIVE: To explore the nature of micromovement and the biomechanical staging of fracture healing. METHODS: Through literature review and theoretical analysis, the difference in micromovement research was taken as the breakthrough point to try to provide a new understanding of the role of micromovement and the mechanical working mode in the process of fracture healing. RESULTS: The process of fracture healing is the process of callus generation and connection. The micromovement is the key to start the growth of callus, and the total amount of callus should be matched with the size of the fracture space. The strain at the fracture end is the key to determine the callus connection. The strain that can be tolerated by different tissues in the fracture healing process will limit the micromovement. According to this, the fracture healing process can be divided into the initiation period, perfusion period, contradiction period, connection period, and physiological period, i.e., the biomechanical staging of fracture healing. CONCLUSION: Biomechanical staging of fracture healing incorporates important mechanical parameters affecting fracture healing and introduces the concepts of time and space, which helps to understand the role of biomechanics, and its significance needs further clinical test and exploration.

Clinical Results of Acetabular Fracture via the Pararectus versus Ilioinguinal Approach.

OBJECTIVE: To compare the clinical efficacy of pararectus and ilioinguinal approach in the treatment of acetabular fractures. METHODS: A retrospective analysis of the clinical data of 60 patients with acetabular fractures treated by the pararectus approach or the ilioinguinal approach from January 2016 to January 2019 was performed to record all data by comparing the length of the surgical incision, the time to expose the fracture and the amount of blood loss during the operation. Patients were routinely followed up at 1, 6 and 12 months postoperatively. The function of the hip joint after the operation (Improved Merle d' Aubigne and Postel scores) and the complications postoperation were recorded. RESULTS: There was a significant difference (mean ± SD) in the length of surgical incision [(11.2 ± 1.5) cm vs.(23.8 ± 2.1) cm], and in surgical exposure time [(10.8 ± 1.7) min vs.(19.9 ± 1.9) min] (P < 0.05) between the two approaches; there was no significant difference (mean ± SD) in intraoperative blood loss [(591.8 ± 131.4) mL vs. (614.6 ± 132.7) mL] or in hip function scores at the last follow-up between the two groups (P > 0.05). In the pararectus approach group, there was one patient (3.3%) with postoperative wound fat liquefaction, and the wound completely improved by secretion culture, enhanced dressing and effective antibiotics, one patient (3.3%) developed lateral femoral cutaneous nerve injury; One case (3.3%) of postoperative myositis ossificans occurred in the ilioinguinal approach group, and there were no obvious symptoms. CONCLUSIONS: These data suggest that for patients with acetabular fractures, both the pararectus approach and the ilioinguinal approach can achieve satisfactory surgical results, but the former has relatively simple operation and small incision length, which is in line with the modern concept of the minimally invasive pelvis.

Cytoplasmic SHMT2 drives the progression and metastasis of colorectal cancer by inhibiting ß-catenin degradation.

Introduction: Serine hydroxymethyltransferase 2 (SHMT2) plays a critical role in serine-glycine metabolism to drive cancer cell proliferation. However, the nonmetabolic function of SHMT2 in tumorigenesis, especially in human colorectal cancer (CRC) progression, remains largely unclear. Methods: SHMT2 expression in human CRC cells was identified by western blot and immunofluorescence assay. The CRC cell proliferation, migration, and invasion after SHMT2 knockdown or overexpression were explored through in vitro and in vivo assays. Immunofluorescence, mRNA-seq, co-immunoprecipitation, chromatin immunoprecipitation-qPCR and immunohistochemistry assays were used to investigate the underlying mechanisms behind the SHMT2 nonmetabolic function. Results: We demonstrated that SHMT2 was distributed in the cytoplasm and nucleus of human CRC cells. SHMT2 knockdown resulted in the significant inhibition of CRC cell proliferation, which was not restored by serine, glycine, or formate supplementation. The invasion and migration of CRC cells were suppressed after SHMT2 knockdown. Mechanistically, SHMT2 interacted with ß-catenin in the cytoplasm. This interaction inhibited the ubiquitylation-mediated degradation of ß-catenin and subsequently modulated the expression of its target genes, leading to the promotion of CRC cell proliferation and metastasis. Notably, the lysine 64 residue on SHMT2 (SHMT2K64) mediated its interaction with ß-catenin. Moreover, transcription factor TCF4 interacted with ß-catenin, which in turn increased SHMT2 expression, forming an SHMT2/ß-catenin positive feedback loop. In vivo xenograft experiments confirmed that SHMT2 promoted the growth and metastasis of CRC cells. Finally, the level of SHMT2 was found to be significantly increased in human CRC tissues. The SHMT2 level was correlated with an increased level of ß-catenin, associated with CRC progression and predicted poor patient survival. Conclusion: Taken together, our findings reveal a novel nonmetabolic function of SHMT2 in which it stabilizes ß-catenin to prevent its ubiquitylation-mediated degradation and provide a potential therapeutic strategy for CRC therapy.

Therapeutic Effect of Acetabular Fractures Using the Pararectus Approach Combined with 3D Printing Technique.

OBJECTIVE: To explore the clinical efficacy of pararectus approach combined with 3D printing technique for the surgical treatment of partial acetabular fractures. METHODS: We retrospectively evaluated 33 (20 males and 13 females) patients with acetabular fractures in the period of June 2017 to December 2018. According to Judet and Letournel classification: 11 cases were of anterior column fracture, 10 cases were of double column fracture, seven fractures were of the anterior column with posterior half transverse, three fractures were of transverse fracture, and two cases were of "T" fracture. For all cases, 3D printing is used to print the acetabular model. Pre-bent reconstruction plates from the model were placed to fixate fractures via the pararectus approach. RESULTS: Thirty-three patients (mean age 48 years; range, 35-63 years), included 20 men and 13 women, were treated successfully with open reduction and internal fixation by the pararectus approach. Surgery duration was 203 min on average (range: 135-245 min), and intra-operative bleeding was 1030 mL on average (range: 450-1400 mL). All patients were followed-up for 12-18 months (average,14 months); two patients (6.0%) developed postoperative ossifying myositis, and there are no obvious symptoms at present; one patient (3.0%) developed postoperative wound infection, and the wound completely improved by secretion culture, enhanced dressing, and effective antibiotics; all the acetabular fractures united after 12 to 16 weeks (average,13 weeks). According to the modified Merle d'Aubigne and Postel scoring system to assess the hip function: excellent in 22 cases (66.7%), good in seven cases (21.2%), and fair in four cases (12.1%). CONCLUSIONS: In the treatment of partial acetabular fractures, the pararectus approach combined with 3D printing technique can achieve effective reduction and fixation, decrease intraoperative hemorrhage, shorten operation time, and the internal fixation position can be properly adjusted during the operation by looking directly at the model.

[Early effectiveness analysis of lateral hinge fracture during medial opening-wedge high tibial osteotomy].

OBJECTIVE: To compare the clinical and radiologic effectiveness in patients with versus without lateral hinge fracture during medial opening-wedge high tibial osteotomy (MOWHTO) to evaluate the effect of lateral hinge fracture on short-term effectiveness. METHODS: The clinical data of 84 patients (97 knees) with medial compartment osteoarthritis who treated with MOWHTO between September 2015 and July 2018 was retrospectively analyzed. There were 10 males (10 knees) and 74 females (87 knees). The age ranged from 45 to 65 years with an average of 57.7 years. Lateral hinge fracture was recognized by the intraoperative fluoroscopy or immediate postoperative X-ray film. Fractures were classified into types Ⅰ, Ⅱ, and Ⅲ according to the Takeuchi classification. The healing of osteotomy was observed by radiographs during follow-up; the femur tibia angle (FTA), medialproximal tibial angle (MPTA), and hip-knee-ankle angle (HKA) were also calculated. The knee joint function was evaluated by Hospital for Special Surgery (HSS) score and knee society score (KSS). RESULTS: The incision healed by first intention. All patients were followed up 15-48 months with an average of 24.8 months. No hinge fracture occurred in 78 knees (80.41%, group A), and lateral hinge fractures were observed in 19 knees (19.59%, group B) and were divided into the type Ⅰ (13 knees, 13.40%) and type Ⅲ (6 knees, 6.19%) groups. Type Ⅰ fractures were not additionally treated, type Ⅲ fractures were anatomic reduced fixed with additional lag screws. X-ray film and CT examination showed that all patients had bone healing at 3 months after operation without delayed healing or nonunion. During follow-up, there was no loosening or fracture of internal fixation plates and screws. HKA, FTA, and MPTA of patients in group A and group B (type Ⅰ and Ⅲ) were significantly improved at each time point after operation compared with preoperative values ( P<0.05); there was no significant difference between groups at each time point before and after operation ( P>0.05). After operation, the pain of knee joint was alleviated and the function of joint was improved. At last follow-up, KSS score and HSS score of groups A and B were significantly improved compared with those before operation ( P<0.05), but there was no significant difference between the two groups ( P>0.05). CONCLUSION: The lateral hinge fracture may occur during MOWHTO. As long as the treatment and rehabilitation were guided according to the fracture classification of the hinge, the effectiveness can be similar to those without the hinge fracture.

[Effectiveness of locking compress plate and extra cortical bone bridge fixation for treatment of atrophic humeral nonunions].

Objective: To assess the effectiveness of locking compress plate and extra cortical bone bridge fixation for treating atrophic humeral nonunion. Methods: Seventeen patients with atrophic humeral nonuninon were treated with locking compress plate and extra cortical bone bridge fixation between November 2006 and June 2015. Of 17 cases, 11 were male, 6 were female, aged 24-63 years (mean, 38.2 years). Fracture located at the left side in 9 cases and at the right side in 8 cases. The mechanism of injury was traffic accident in 13 cases, falling from height in 3 cases, and heavy pound injury in 1 case. The patients underwent surgery for 1 time in 7 cases, for 2 times in 5 cases, for 3 times in 4 cases, and for 4 times in 1 case. The time from fracture to hospitalization was 10-76 months (mean, 22.6 months). The shoulder function was evaluated by Neer score, and elbow function by Mayo score. Results: All incisions healed by first intention. Two cases had transient radial nerve symptoms of numbness. All patients were followed up 27.3 months on average (range, 15-60 months). Radiographic examination showed signs of bone remodeling at 6-8 weeks after operation, and formation of extra cortical bone bridge. All of them achieved bone union within 10 to 41 weeks (mean, 17.6 weeks). At last follow-up, the average Neer score was 83.36 (range, 72-96); and the shoulder function was excellent in 10 cases, good in 5, and fair in 2 with an excellent and good rate of 88.24%. And the average Mayo score was 86.52 (range, 68-100); and the elbow function was excellent in 11 cases, good in 3, and fair in 3 with an excellent and good rate of 82.35%. Conclusion: The bone bridging could effectively form by extra cortical grafting technique. Atrophic humeral nonunions can be successfully treated with locking compress plate and extra cortical bone bridge fixation.

[Application of three-dimensional printing technology for closed reduction and percutaneous cannulated screws fixation of displaced intraarticular calcaneus fractures].

Objective: To evaluate the effectiveness of three-dimensional (3-D) printing assisting minimally invasive for intraarticular calcaneal fractures with percutaneous poking reduction and cannulate screw fixation. Methods: A retrospective analysis was performed of the 19 patients (19 feet) with intraarticular calcaneal fracture who had been treated between March 2015 and May 2016. There were 13 males and 6 females with an average age of 38.2 years (range, 24-73 years). There were 3 open fractures and 16 closed fractures. By Sanders classification, 12 cases were type Ⅱ, 7 cases were type Ⅲ. By Essex-Lopresti classification, 13 cases were tongue type, 6 cases were joint-depression type. The time from injury to surgery was 1-10 days (mean, 4.7 days). A thin slice CT scan was taken of bilateral calcaneus in patients. By using the mirror imaging technique, the contralateral mirror image and the affected side calcaneus model were printed according to 1∶1 ratio. The displacement of fracture block was observed and contrasted, and the poking reduction was simulated. Calcaneal fracture was treated by percutaneous minimally invasive poking reduction and cannulate screw fixation. The Böhler angle and Gissane angle at immediate after operation and last follow-up was measured on X-ray films, and compared with preoperative measurement. The functional recovery was evaluated by American Orthopaedic Foot and Ankle Society (AOFAS) scores. Results: The operation time was 25-70 minutes (mean, 45 minutes). The intraoperative blood loss was 10-40 mL (mean, 14.5 mL). All the incisions healed by first intention and had no relevant postoperative complications such as skin necrosis, nail tract infection, and osteomyelitis. All the patients were followed up 12-25 months (mean, 14.6 months). All patients obtained fracture healing, and the fracture healing time was 8-14 weeks (mean, 10.3 weeks). No screw withdrawal or breakage occurred during follow-up; only 1 patient with Sanders type Ⅱ fracture, whose calcaneus height was partially lost at 6 weeks after operation, the other patients had no reduction loss and fracture displacement, and no traumatic arthritis occurred. The Böhler angle and Gissane angle at immediate after operation and last follow-up were significantly improved when compared with preoperative ones ( P<0.05), but there was no significant difference between at immediate after operation and last follow-up ( P>0.05). The AOFAS score was 76-100 (mean, 88.2), and the results were excellent in 10 feet, good in 7, and fair in 2, the excellent and good rate was 89.5%. Conclusion: 3-D printing assisting minimally invasive for intraarticular calcaneal fractures with percutaneous poking reduction and cannulate screw fixation can reduce the surgical trauma, improve the quality of reduction and fixation, and make the operation more safe, accurate, and individualized.

Over-expression of Sox4 and ß-catenin is associated with a less favorable prognosis of osteosarcoma.

The purpose of this study was to examine the association of the expression of Sox4 and ß-catenin with the prognosis of osteosarcoma. A total of 108 cases of conventional osteosarcoma were involved in this study and 28 cases of osteochondroma served as controls. The expression of Sox4 and ß-catenin was detected by using immunohistochemical staining and Western blotting. The results showed that Sox4 and ß-catenin were over-expressed in 67 (62.03%) and 62 (57.41%) of 108 osteosarcoma cases, while in only 3 (10.71%) and 5 (17.86%) of 28 controls, respectively (P<0.05 for all). The expression of Sox4 and ß-catenin was associated with the distant metastasis, pathological grade and Enneking stage of patients with osteosarcoma (P<0.05 for all). The mean overall survival time and the 5-year-survival rate in osteosarcoma patients with Sox4 and ß-catenin over-expressed were significantly reduced as compared with those in Sox4 and ß-catenin low-expression group (P<0.05 for all). Cox multifactor regression analysis revealed that the distant metastasis, Enneking stage, and the expression of Sox4 and ß-catenin were independent risk factors of patients with osteosarcoma (P<0.05 for all). The findings indicated that overexpression of Sox4 and ß-catenin is associated with a poor prognosis of osteosarcoma.

[LONG-TERM EFFECTIVENESS OF TRANSPIANTATION OF ILIAC BONE FLAP PEDICLED WITH DEEP ILIAC CIRCUMFLEX VESSELS FOR AVASCULAR NECROSIS OF FEMORAL HEAD AT STAGE II AND III].

OBJECTIVE: To assess the long-term effectiveness of the transplantation of iliac bone flap pedicled with deep iliac circumflex vessels for treating avascular necrosis of femoral head (ANFH) at Ficat stage II and III. METHODS: Thirty-two cases (43 hips) of ANFH underwent iliac bone flap transplantation pedicled with deep iliac circumflex vessels between October 2000 and February 2006, and the clinical data were retrospectively reviewed. Of 32 cases, 27 were male (38 hips), and 5 were female (5 hips), aged 21-52 years (mean, 36.6 years); there were 8 cases (11 hips) of hormone ANFH, 18 cases (23 hips) of alcoholic ANFH, and 6 cases (9 hips) of idiopathic ANFH. The disease duration ranged from 2-52 months (mean, 8.2 months). According to Ficat staging criteria, 26 hips were classified as stage II and 17 hips as stage III. The preoperative Harris hip score (HSS) was 68.2±8.4. The HHS scores and X-ray photograph were compared between at pre- and post-operation to assess the outcomes clinically and radiologically. RESULTS: All incisions healed by first intention. Two cases had numbness of the lateral femoral skin. Four patients (6 hips) failed to be followed up, and the other 28 cases were followed up 98-187 months (mean, 129.3 months). Five patients (6 hips) showed aggravation or no relief with progression to stage IV at 8-69 months, who received total hip arthroplasty. The 10-year survival rate was 83.78% (31/37). The HHS score was significantly increased to 86.7±9.0 at last follow-up (t=-48.313, P=0.000). The hip function was excellent in 9 hips, good in 13 hips, and fair in 9 hips, and the success rate was 75.68%. Radiographic examination showed signs of bone remodeling at 6-8 weeks. After bone healing, the femoral head density gradually became uniform. Until last follow-up, ANFH progressed from Ficat stage II to III in 5 hips, from Ficat stage II to IV in 3 hips, and from Ficat stage III to IV in 3 hips; complete hip shape, continuous Shenton line, and normal joint space were observed in the other 26 hips, and the radiographic success rate was 70.27% (26/37). CONCLUSIONS: The pedicled iliac bone flap transplantation for ANFH at Ficat stage II and III can provide good osteogenesis and vascular reconstruction of the femoral head. The long-term follow-up effectiveness is satisfactory.

[AN EXPERIMENTAL STUDY ON REPAIR OF SCIATIC NERVE INJURY BY Schwann-LIKE CELLS DERIVED FROM UMBILICAL CORD BLOOD MESENCHYMAL STEM CELLS].

OBJECTIVE: To evaluate the effect of using Schwann-like cells derived from human umbilical cord blood mesenchymal stem cells (hUCBMSCs) as the seed cells to repair large sciatic nerve defect in rats so as to provide the experimental evidence for clinical application of hUCBMSCs. METHODS: Fourty-five male Sprague Dawley (SD) rats in SPF grade, weighing 200-250 g, were selected. The hUCBMSCs were harvested and cultured from umbilical cord blood using lymphocyte separating and high molecular weight hydroxyethyl starch, and then was identified. The hUCBMSCs of 3rd generation were induced to Schwann-like cells, and then was identified by chemical derivatization combined with cytokine. The acellular nerve basal membrane conduit was prepared as scaffold material by the sciatic nerve of SD rats through repeated freezing, thawing, and washing. The tissue engineered nerve was prepared after 7 days of culturing Schwann-like cells (1 x 10(7) cells/mL) on the acellular nerve basal membrane conduit using the multi-point injection. The 15 mm sciatic nerve defect model was established in 30 male SD rats, which were randomly divided into 3 groups (10 rats each group). Defect was repaired with tissue engineered nerve in group A, with acellular nerve basal membrane conduit in group B, and with autologous sciatic nerve in group C. The nerve repair was evaluated through general observation, sciatic function index (SFI), nerve electrophysiology, weight of gastrocnemius muscle, and Masson staining after operation. RESULTS: The hUCBMSCs showed higher expression of surface markers of mesenchymal stem cells, and Schwann-like cells showed positive expression of glia cell specific markers such as S100b, glial fibrillary acidic protein, and P75. At 8 weeks after operation, the acellular nerve basal membrane conduit had no necrosis and liquefaction, with mild adhesion, soft texture, and good continuity at nerve anastomosis site in group A; group B had similar appearance to group A; adhesion of group C was milder than that of groups A and B, with smooth anastomotic stoma and no enlargement, and the color was similar to that of normal nerve. SFI were gradually decreased, group C was significantly greater than groups A and B, group A was significantly greater than group B (P < 0.05). The compound action potential could be detected in anastomotic site of 3 groups, group C was significantly greater than groups A and B, and group A was significantly greater than group B in amplitude and conduction velocity (P < 0.05). Atrophy was observed in the gastrocnemius of 3 groups; wet weight's recovery rate of the gastrocnemius of group C was significantly greater than that of groups A and B, and group A was significantly greater than group B (P < 0.05). Masson staining showed that large nerve fibers regeneration was found in group A, which had dense and neat arrangement with similar fiber diameter. The density and diameter of medullated fibers, thickness of myelinated axon, and axon diameter of group C were significantly greater than those of groups A and B, and group A was significantly greater than group B (P < 0.05). CONCLUSION: Tissue engineered nerves from hUCBMSCs-derived Schwann-like cells can effectively repair large defects of the sciatic nerve. hUCBMSCs-derived Schwann-like cells can be used as a source of seed cells in nerve tissue engineering.

[PEDICLED ILIAC PERIOSTEAL FLAP GRAFT FOR AVASCULAR NECROSIS OF FEMORAL HEAD AFTER FEMORAL NECK FRACTURE IN ADOLESCENTS].

OBJECTIVE: To assess the effectiveness of pedicled iliac periosteal flap graft for treatment of avascular necrosis of the femoral head (ANFH) after femoral neck fracture in adolescents. METHODS: Between December 2006 and August 2011, 9 patients (9 hips) with ANFH after femoral neck fracture were treated with pedicled iliac periosteal flap graft. There were 6 males and 3 females with an average age of 14.7 years (range, 10-18 years). Fractures were caused by traffic accident injury (5 cases), falling injury from height (3 cases), and fall injury (1 case). The time from injury to internal fixation with Kirschner wires or cannulated screws was 3-16 days, and all fractures healed within 10 months after internal fixation. The interval between fracture fixation and ANFH was 10-42 months (mean, 24.4 months). According to Steinberg staging system, 1 hip was classified as stage IIIb, 2 hips as stage IIIc, 1 hip as stage IVa, 3 hips as stage IVb, and 2 hips as stage IVc. The Harris scores and Steinberg classification were compared between at pre- and post-operation to assess the outcomes clinically and radiologically. RESULTS: All incisions healed by first intention. No complications of infection, deep venous thrombosis of lower limb, and pain and numbness of donor site were observed during or after operation. All patients were followed up 38-76 months (mean, 52 months). Joint pain was relieved; no leg length discrepancy was observed; the walking gait was improved and range of motion of hips was increased. The Harris score was significantly increased from 62.8 ± 3.6 at pre-operation to 92.7 ± 9.9 at last follow-up, showing significant difference (t = -12.244, P = 0.000). The hip function was excellent in 5 hips, good in 3 hips, and poor in 1 hip, and the excellent and good rate was 88.89%. Post-operative radiological assessment demonstrated that only 1 hip (stage IIIb) had further collapse of the femoral head, the other hips had no incidence of deterioration. The radiological success rate was 88.89% (8/9). CONCLUSION: The pedicled iliac periosteal flap graft for ANFH after femoral neck fracture in adolescents can provide good osteogenesis and vascular reconstruction of the femoral head.

Inhibitory effects of forkhead box L1 gene on osteosarcoma growth through the induction of cell cycle arrest and apoptosis.

Forkhead box L1 (FOXL1), which is considered a novel candidate tumor suppressor, inhibits proliferation and invasion in certain types of cancer. However, the regulation and function of FOXL1 in osteosarcoma remains unclear. The expression of FOXL1 gene in osteosarcoma tissues and cell lines was examined using RT-PCR, immunohistochemistry and western blot analysis. pcDNA-FOXL1 carrying full-length FOXL1 cDNA was constructed to upregulate the level of FOXL1 expression in osteosarcoma cell lines. The proliferation, cell cycle and apoptosis of osteosarcoma cells in vitro or in vivo were examined following transfection with pcDNA-FOXL1. In addition, the expression of p21, p27, cytochrome c and caspase-3, which may be involved in the regulation of the cell cycle and apoptosis was examined using western blot analysis. The results showed that FOXL1 expression was downregulated in osteosarcoma tissues and cell lines. Loss or downregulation of FOXL1 was associated with poor prognosis. Ectopic FOXL1 expression inhibited cell proliferation in vitro and in vivo. The ectopic FOXL1 expression increased the expression of p21 and p27, which induced G1 arrest in the U-2 OS cells. In addition, the ectopic FOXL1 expression induced cytochrome c release between mitochondria and cytoplasm, which disrupted the mitochondrial transmembrane potential and triggered intrinsic pathway apoptosis. In conclusion, the downregulation of FOXL1 expression was associated with osteosarcoma cell growth. Restoration of FOXL1 gene expression by gene therapy may have a therapeutic potential for patients with osteosarcoma.

[PERCUTANEOUS Kirschner WIRE POKING REDUCTION AND ELASTIC STABLE INTRAMEDULLARY NAILING FIXATION FOR SEVERE DISPLACED RADIAL NECK FRACTURES IN CHILDREN].

OBJECTIVE: To assess the effectiveness of percutaneous Kirschner wire poking reduction and elastic stable intramedullary nailing fixation for treating severe displaced radial neck fractures in children. METHODS: Between November 2010 and August 2014, 17 children with severe displaced radial neck fractures were treated with percutaneous Kirschner wire poking reduction and elastic stable intramedullary nailing fixation. There were 13 boys and 4 girls with an average age of 8.7 years (range, 6-14 years). The right side was involved in 9 cases, and the left side was involved in 8 cases. The causes of injury were falling in all cases. The angular deformity at fracture was 64-102° (mean, 84°). According to the Judet classification, 7 cases were classified as grade IVa and 10 cases as grade IVb. The time from injury to operation was 4.2 days (range, 1-7 days). Metaizeau classification and Tibone-Stoltz elbow performance score were used to access the radiological and clinical results, respectively. RESULTS: The operation time was 20-50 minutes (mean, 30 minutes). All incisions healed by first intention. The patients were followed up 12-46 months (mean, 20 months). All fractures healed at 2 months after operation. There was no complication of malunion, early epiphyseal closure, avascular necrosis, enlargement of the radial head epiphysis, cubitus varus and valgus deformities, or proximal radioulnar joint synostosis. One case had elbow extension limitation. At last follow-up, the elbow range of motion in flexion, extension, pronation, and supination showed no significant difference between affected side and normal side (P>0.05). The clinical results were excellent in 16 cases and good in 1 case, with an excellent and good rate of 100%. The angulation was 0-12° (mean, 3.7°) on the X-ray film; anatomic reduction or nearly anatomic reduction was obtained, and the radiological results were excellent in 13 cases and good in 4 cases, with an excellent and good rate of 100%. CONCLUSION: Percutaneous Kirschner wire poking reduction followed by fixation with elastic stable intramedullary nailing is a simple, safe, minimally invasive, and effective method to treat severe displaced radial neck fractures in children.

Differentiation of Schwann­like cells from human umbilical cord blood mesenchymal stem cells in vitro.

The use of artificial nerves for the repair of peripheral nerve defects is restricted by the limited sources of Schwann cells (SCs). Human mesenchymal stem cell (MSC)­derived Schwann­like cells are considered an alternative and desirable cell source. The aim of the present study was to establish a method of inducing directional differentiation of human umbilical cord blood (hUCB) MSCs into Schwann­like cells. Cells isolated from hUCB were cultured in MesenCult complete medium, a specialized culture medium for MSCs, to expand hUCBMSCs. hUCBMSCs were purified by repeated changing of the medium, and they were identified by detection of the specific cell surface markers for MSCs. For differentiation of Schwann­like cells from hUCBMSCs, the purified cells were sequentially cultured in DMEM/F12 medium with various additives. Differentiated Schwann­like cells were identified by the detection of SC­specific markers, including S100b, glial fibrillary acidic protein and P75, by immunocytochemisty, reverse transcription­polymerase chain reaction and western blotting. The results demonstrated that the majority of the differentiated cells presented classical dipolar and fusiform SC morphology. Notably, a large proportion of these cells expressed the three SC markers. These results suggest that hUCBMSCs can undergo directional differentiation into Schwann­like cells in vitro and may be an important source of SCs for the treatment of peripheral nerve defects with tissue­engineered artificial nerves.

[ALLOTRANSPLANTATION OF CRYOPRESERVATED VASCULARIZED BONE IN LIMB SALVAGE SURGERY FOR CHILDREN AND ADOLESCENTS WITH OSTEOSARCOMA].

OBJECTIVE: To investigate the effectiveness and technical key points of limb salvage surgery by allotransplantation of cryopreservated vascularized bone in children and adolescents with osteosarcoma. METHODS: A retrospective analysis was made on the clinical data of 21 children and adolescents with osteosarcoma receiving limb salvage surgery by allotransplantation of cryopreservated vascularized bone from their relatives between February 2004 and April 2012. There were 13 males and 8 females, aged from 7 to 16 years (mean, 12.6 years). According to Enneking stage system, 15 cases were rated as stage IIA and 6 cases as stage IIB. The tumors located at the distal femur in 10 cases, at the proximal femur in 1 case, at the proximal tibia in 8 cases, at the proximal humerus in 1 case, and at the distal radius in 1 case. Imaging examination showed that epiphyseal extension of malignant bone tumors in 7 cases. The iliac bone allograft with deep iliac vessels was obtained from their lineal consanguinity. After preservation by a two-step freezing schedule, the iliac bone allograft with deep iliac vessels was implanted into the bone defect area after tumor resection. The size of iliac bone flap was 8.0 cm x 3.0 cm x 2.0 cm-14.0 cm x 5.0 cm x 2.5 cm. Reserved joint surgery was performed on 16 cases and joint fusion surgery on 5 cases, and external fixation was used in all cases. The chemotherapy was given according to sequential high-dose methotraxate, adriamycin, and cisplatine before and after operation. RESULTS: All 21 cases were followed up from 5 months to 11 years (mean, 6.4 years). At 2 weeks after operation, the erythrocyte rosette forming cells accounted for 56.7% ± 3.9%, showing no significant difference when compared with that of normal control (58.3% ± 4.3%) (t = 1.56, P = 0.13), which suggested no acute rejection. At 4 weeks after operation, single photon emission computerized tomography bone scan indicated that the blood supply of bone graft was rich, and the metabolism was active. At 12 weeks after operation, the digital subtraction angiography showed the artery of iliac bone flap kept patency. X-ray films showed that malunion and non-union occurred at 5 and 6 months after operation in 1 case, respectively. The bone graft healed in the other patients, and the healing time was 3.2-6.0 months (mean, 4.4 months). At last follow-up, American Musculoskeletal Tumor Society (MSTS) score was significantly improved to 26.80 ± 2.14 from preoperative value (17.15 ± 1.86) (t = -4.15, P = 0.00). The survival rate was 85.7% (18/21) and the recurrence rate was 9.5% (2/21). CONCLUSION: Allotransplantation of cryopreservated vascularized bone from the relatives provides a new method for the treatment of osteosarcoma in children and adolescents. A combination of allotransplantation and chemotherapy can achieve the ideal treatment effect. The correct cutting, preservation, and transplantation of the donor bone, and indication are the key to improve the effectiveness.

Effects of adenoviral vector expressing hIGF-1 on apoptosis in nucleus pulposus cells in vitro.

The excessive apoptosis of cells of the nucleus pulposus may plays an important role in intervertebral disc (IVD) degeneration. It has been shown that the pro-inflammatory cytokine tumour necrosis factor (TNF)-α can induce disc cell apoptosis. Insulin-like growth factor (IGF)-1 can promote nucleus pulposus cell proliferation; however, whether or not IGF-1 inhibits TNF-α-induced apoptosis in the nucleus pulposus has not yet been elucidated. In this study, our objective was to create a potentially therapeutic viral vector, which could be used to achieve the enforced expression of IGF-1 in rabbit nucleus pulposus cells. Furthermore, we investigated the ability of IGF-1 to reverse TNF-α-induced apoptosis in cells of the nucleus pulposus. Isolated nucleus pulposus cells were cultured to a confluent monolayer, digested with collagenase Ⅱ and purified using trypsin and differential adhesion methods. Nucleus pulposus cells were positively identified using type Ⅱ collagen immunohistochemistry. Following transfection with adenoviral vectors engineered to overexpress recombinant human IGF-1 (Ad-hIGF-1) or TNF-α, the cells were observed under a light microscope. Terminal deoxynucleotidyl transferase (TdT)-mediated dUTP-biotin nick end-labeling (TUNEL) and flow cytometry (FCM) were used to assess the rate of apoptosis. The Ad-hIGF-1 viral vector was effectively transduced into the nucleus pulposus cells and increased IGF-1 expression as confirmed by RT-PCR and western blot analysis. In the TNF-α-treated group, a large number of apoptotic cells was observed that exhibited morphological changes associated with this form of cell death. Minimal apoptosis was observed in the Ad-hIGF-1-treated group and the control group showed no obvious signs of apoptosis. TUNEL assay revealed that the rate of apoptosis in the Ad-hIGF-1 group was significantly reduced compared with the TNF-α-treated group (P<0.01). This result was confirmed using FCM. The rate of apoptosis was also significantly increased in the TNF-α-exposed cells compared with the control group (P<0.01). Our findings strongly suggest that the adenoviral vector expressing hIGF-1 can successfully infect nucleus pulposus cells in vitro and effectively enhance the expression of IGF-1. In addition, IGF-1 reversed the TNF-α -induced apoptosis of nucleus pulposus cells. Thus, Ad-hIGF-1 may be useful in the development of clinical interventions for disc degeneration.

[Clinical anatomy study on autonomic nerves related to anterior approach lumbar surgery ].

OBJECTIVE: To understand the location characteristics of the lumbosacral autonomic nerve plexus and the morphological changes so as to provide the anatomic theoretical basis for the protection of autonomic nerve during the lower lumbar anterior approach operation. METHODS: A random anatomic investigation was carried out on 19 formalin-treated adult cadavers (15 males and 4 females; aged 44-78 years, mean 64 years). The anterior median line (connection of suprasternal fossa point and the midpoint of the symphysis pubis) was determined, and the characteristics of abdominal aortic plexus (AAP), inferior mesenteric plexus (IMP), and superior hypogastric plexus (SHP) were observed. The relationship between the autonomic nerve and the anterior median line was measured and recorded. RESULTS: APP and IMP were found to be located chiefly in front of the abdominal aorta in a reticular pattern, and the nerve fibers of the two nerve plexuses were more densely at the left side of abdominal aorta than at the right side. Superior hypogastric plexus showed more distinct main vessel variations, including 4 types. The main vessel length of the SHP was (59.38 ± 12.86) mm, and the width was (11.25 ± 2.92) mm. The main vessels of SHP were mainly located at the left side of the ventral median line (10, 52.6%) and anterior lumbar vertebra (13, 68.4%). The main vessels extended down to form the left and right hypogastric nerves. CONCLUSION: It is applicable to expose the nerve from the right side of centrum and move the autonomic nerve and blood vessel as a whole during anterior lower lumbar operation. In this way, the dissection to separate nerve plexus is not needed, thus nerve injury can be avoided to the largest extent.