We obtained recombinant ferritin from Dermatophagoides f arinae ,and analyzed the characterization of the pro‐tein .A pair of primers was designed according to the known sequence of ferritin gene .The live mites identified and cultured lo‐cally were picked and the total RNA was extracted .The ferritin gene fragment was amplified by RT‐PCR ,and cloned into pET32a vector ,and then transferred into E .coli Top10 .The target gene obtained from the recombinant plasmid by digestion with Bam HⅠand Hind Ⅲ was connected to the prokaryotic expression vector pET‐32a .The expressed recombinant plasmid containing ferritin gene was constructed by cloning target gene into pET‐32a and transferred into E .coli Bl21 (DE3) .The ex‐pressed recombinant protein was analyzed by SDS‐PAGE ,and was purified by immobilized metal ion affinity chromatography (IMAC) .The ferritin expressed by dust mite was analyzed by the method of bioinformatics .The recombinant plasmid pET32a‐ferritin was constructed .SDS‐PAGE showed a correct molecular weight of the recombinant ferritin protein .After purification by affinity chromatography ,the protein showed only one strip on SDS‐PAGE gel .SDS‐PAGE showed a band at 20 kD .Dust mite ferritin contains 8 serine kinase ,7 threonine kinase ,7 tyrosine kinase ,and 0 histidine kinase phosphorylation sites .Hy‐drophilic region is larger than the hydrophobic region and it is an unstable protein .In conclusion ,the ferritin gene has been cloned and expressed .The purified ferritin has high purity . The study provides a basis for further study of composition and physicochemical properties of house dust mite allergen .

Objective:To evaluate the anterior expansion of sacral foramen and decompression of sacral plexus via the lateral-rectus approach (LRA) in the surgical treatment of sacral fractures complicated with sacral plexus injury.Methods:From January 2013 to June 2018, 11 patients were treated at Department of Orthopaedics, The Third Hospital Affiliated to Southern Medical University for obsolete sacral fractures complicated with sacral plexus injury. They were 8 males and 3 females, aged from 17 to 54 years (average, 38 years). According to the Denis classification, all the sacral fractures belonged to Denis Zone Ⅱ. According to British Medical Research Council (BMRC) grading system, the nerve injury was complete damage in 2 cases and partial damage in 9. The mean time from injury to surgery was 6 months (range, from 0.7 to 12.0 months). After the sacroiliac joint was exposed via the LRA, the lumbosacral trunk was exposed and released between iliac vessels and the iliopsoas. Next, the S1 foramen was expanded and the S1 nerve root was released after separation of the median sacral artery and the internal iliac artery. Reduction and fixation of the sacroiliac joint was carried out for patients with unstable sacral fracture. X-ray and CT examinations of the pelvis were performed to evaluate fracture healing and neurological function recovery postoperatively.Results:Of this cohort of 11 cases, operation succeeded in 10 but failed in one whose sacral fracture was found to have completely healed with the S1 foramina totally occluded. The surgical time averaged 110 min (range, from 70 to 220 min) and the blood loss 1, 100 mL (range, from 450 to 2, 800 mL). Postoperative X-ray and CT examinations showed that the sacral foramens were expanded significantly without any complications. The follow-up time averaged 18 months (range, from 12 months to 4 years). By the BMRC grading system at the last follow-up, the neural function was completely recovered in 5 cases, partially recovered in 4 cases and not recovered in one.Conclusion:Significant anterior expansion of sacral foramen and decompression of sacral plexus via the LRA is a viable and effective alternative for treatment of sacral fractures complicated with sacral plexus injury.

Objective:To investigate the clinical efficacy of lateral-rectus approach(LRA) for vertical shear fracture of pelvis combined with lumbosacral plexus nerve injury.Methods:A retrospective study was conducted of the 37 patients who had been treated at Department of Orthopaedics, The Third Affiliated Hospital to Southern Medical University for vertical shear pelvic fracture combined with lumbosacral plexus nerve injury from August 2010 to August 2018. They were 25 males and 12 females, aged from 18 to 61 years (mean, 36.2 years). By the Tile classification, there were 31 cases of type C1.3, 5 cases of type C2 and one of type C3. LRA was used in all the patients to explore and release the lumbosacral plexus nerve and to reduce the sacral fracture. The posterior ring was fixated with an anterior iliac plate or sacral screws before fixation of the anterior ring and treatment of the acetabular fracture. The operation time, intraoperative bleeding volume, quality of fracture reduction, fracture union time and recovery of nerve and muscle strength were recorded.Results:For this cohort, the operation time ranged from 105 to 228 minutes (mean, 155.0 minutes) and the intraoperative bleeding volume from 680 to 2, 440 mL (mean, 1, 070 mL). Thefollow-up time ranged from 1 to 8 years (average, 2 years). According to the Matta criteria, the quality of fracture reduction was evaluated as excellent in 21 cases, as good in 12 cases and as fair in 4 cases, giving an excellent and good rate of 89.2%. Follow-ups revealed reduction loss in 4 patients, nonunion and reduction loss in one patient and bony union in the other 32 patients after 8 to 12 weeks (mean, 10.1 weeks). According to the criteria by the Nerve Injuries Committee of the British Medical Research Council (BMRC), the recovery of nerve and muscle strength achieved M5 (full recovery of neurological symptoms) in 22 cases, M4 (fine recovery of neurological symptoms) in 7 cases, M1, M2 and M3 (partial recovery of neurological symptoms) in 5 cases, and M0 (no recovery of neurological symptoms) in 3 cases.Conclusion:LRA is an ideal surgical approach for treatment of pelvic vertical shear fractures complicated with lumbosacral plexus nerve injury, because it can well expose the medial pelvic joint from the sacroiliac joint to the symphysis pubis, allow direct release of the lumbosacral plexus nerve compressed and stretched, and, together with traction of the lower limbs, lead to satisfactory fracture reduction.

Objective: To explore surgical technique and clinical results of the direct posterior approach (DPA) for acetabular fractures involving posterior column, posterior wall, or posterior column and wall. Methods: From January 2016 to June 2017, data of 10 cases (7 males, 3 females, an average age of 37 years, ranging from 17 to 54 years) with posterior acetabular fractures treated by the DPA were retrospectively analyzed. Fractures were caused by traffic accident in 6 cases and by falling in 4 cases. According to Letournel-Judet classification of acetabular fractures, there were 6 cases of posterior acetabular wall fractures, 4 cases of posterior wall fractures involving posterior column. A straight skin incision was made from the middle of the line between the posterior margin of the tip of the femoral greater trochanter and the posterior superior iliac spine, to the posterior margin of the femoral greater trochanter. The gluteus maximus muscle was cleaved longitudinally. A view of the area from hip capsule to the superior margin of the greater sciatic foramen was obtained by entering along the interspace of the gluteus medius and pyriformis muscle, and the superior gluteal neurovascular bundle was protected. Acetabular posterior column and posterior wall fractures were reduced and fixed under direct vision. The fracture reduction, fracture healing, femoral head necrosis, sciatic nerve injury, superior gluteal neurovascular injury and heterotopic ossification were evaluated by the postoperative X-ray and CT examination. The function of hip joint was assessed by the Merle d’Aubigné-Posteal score modified by Matta. Results: The average operative incision length was 9.6 cm (range, 8-11 cm). The average operation time was 50 min (range, 35-80 min). The average blood loss was 310 ml (range, 200-440 ml). The time of follow-up was 12-30 months. All the patients were healed within 8-12 weeks without any complications such as superior gluteal nerve injury, superior gluteal vessel injury, or sciatic nerve injury. One case of acetabular posterior wall and posterior column fracture with posterior dislocation of hip joint, suffered from femoral head necrosis at the 9th months after surgery, which was treated by total hip arthroplasty and was recovered one year after surgery. In one case of actebular posterior wall and posterior column fracture, heterotopic ossification occurred 3 month after operation, without any special treatment and the hip joint activity was not affected at the follow-up of 15 months after surgery. During the 12-month follow-up after surgery, the Merle d’Aubigné-Postel score modified by Matta was 13-18, among which there were excellent in 6 cases, good in 2, acceptable in 2, with an overall excellent and good rate of 80% (8/10). Conclusion The direct posterior approach for posterior acetabular fractures can obtain satisfactory clinical results. The advantages of the DPA include decreasing trauma, shortening operation time, reduing blood loss and decreasing risks of iatrogenic injury to the gluteus medius muscle, the external rotators, the arteriae circumflexa femoris medialis and sciatic nerves as well as reducing and fixing the fractures under direct vision. Thus, the DPA is a relatively safe surgical approach for acetabular posterior wall/column fracture.

Objective:To investigate the surgical techniques and clinical efficacy of periacetabular osteotomy through the lateral-rectus approach (LRA) for obsolete acetabular fractures.Methods:The 22 patients with old acetabular fracture were retrospectively analyzed who had been admitted to Department of Traumatic Surgery, The Third Affiliated Hospital to Southern Medical University from June 2012 to June 2019. They were 16 males and 6 females, aged from 22 to 61 years (average, 45.0 years). By the Judet-letournel classification, there were 4 anterior + posterior hemitransverse fractures, 2 T-shaped fractures and 16 both column fractures. The time from injury to surgery was 3 to 12 weeks in 15 cases, 3 to 6 months in 5 cases, 9 months in one case, and 3 years in one case. After the whole acetabulum was exposed outside the peritoneum through LRA in all patients, periacetabular osteotomy was conducted under direct vision, followed by fixation with multiple reconstruction plates or integrated acetabular airfoil anatomical plates after reduction. Recorded were the operation time, intraoperative blood loss, fracture reduction quality, affected hip function and complications in the patients.Results:In this cohort the operation time ranged from 110 to 205 min, averaging 140.5 min; intraoperative blood loss ranged from 500 to 2,100 mL, averaging 1,250.4 mL. According to the Matta X-ray criteria, the postoperative reduction was assessed as excellent in 7 cases, as good in 11 and as poor in 4, yielding an excellent and good rate of 81.8% (18/22). All the 22 patients were followed up for 12 to 36 months (mean, 22.1 months) and achieved fracture union. The one-year follow-up showed that their modified Merle d'Aubigné & Postel scores ranged from 6 to 18 points, averaging 14.6 points and giving 6 excellent, 10 good, 3 fair and 2 poor cases [an excellent and good rate of 72.7% (16/22)]. Osteonecrosis of the femoral head developed in 2 patients one of whom underwent total hip replacement.Conclusions:As LRA can expose the entire hemipelic ring from the medial side of the pelvis, the periacetabular osteotomy can be performed and the fractures of anterior or posterior column and the quadrilateral area can be reduced under direct vision through the medial side of the acetabulum. Moreover, ideal results can be achieved with the use of multiple reconstruction plates or integrated acetabular airfoil anatomical plates.

Objective:To explore the surgical method and clinical efficacy of lateral-rectus approach (LRA) in the treatment of fragility fractures of the pelvis (FFP) in the elderly.Methods:A retrospective study was conducted for elderly FFP patients from January 2011 to December 2019. All the pelvic fractures should be exposed and reduced through LRA and fixed with pelvic reconstruction plates and channel screws. Then, a total of 30 elderly patients were included in the study, including 9 males and 21 females, with an average age of 72.5 years (range, 60-87 years). Fractures were caused by car accident in 5 cases, by falling from high places in 8 cases and by tumbling in 17 cases. According to the FFP classification, there were 6 cases of type IIc (6/30, 20%), 22 cases of type III (22/30, 73.33%, of which 13 cases were type IIIa, 7 cases were type IIIb, and 2 cases were type IIIc), 2 cases of type IVa (2/30, 6.67%). Among that, 2 cases suffered ipsilateral acetabular fractures, 17 suffered medical diseases such as hypertension, coronary heart disease, diabetes, etc., and none suffered extremities fractures or other types of injuries. Surgical field was exposed retroperitoneally through LRA, combined with lower limb traction to reduce the anterior and posterior pelvis ring fractures. Then, the reductions were done in direct visions and verified through X-ray fluoroscopy. After that, the posterior ring was fixed with reconstruction plate and/or sacroiliac screws, and the anterior ring was fixed with reconstruction plate or INFIX. The quality of fracture reduction was evaluated by Matta score and the postoperative function was evaluated by Majeed score.Results:All the 30 patients were surgical treated through LRA. The time from injury to operation was 5 to 20 days, with an average of 9.9 days. The operating time ranged from 35 to 150 min (mean, 73.5 min) and the intraoperative bleeding ranged from 220 to 2 400 ml (mean, 586.7 ml). Fractures were successfully reduced under direct vision and the positions of the plates and screws were monitored through X-ray fluoroscopy during the operation. Postoperative X-rays and CT scans showed satisfactory reduction of the pelvic ring. According to Matta criteria, the quality of fracture reduction was evaluated as excellent in 18 cases, good in 6 cases, fair in 4 cases and poor in 2 cases. The overall excellent and good rate was 80% (24/30). All patients were followed up for 6-24 months, the fractures were all healed, and all fractures healed for 2-5 months, with an average of 3.5 months. At the last follow-up, Majeed scores were 86.1±6.11 (range, 66-92), including 21 excellent cases, 7 good cases and 2 fair cases, with an excellent and good rate of 93.3% (28/30). As for complications, 1 patient developed deep venous thrombosis of the affected lower limb, and the thrombosis disappeared after thrombolytic therapy. One patient had fat liquefaction in the incision, and the wound healed after intensive dressing change. After INFIX fixation, 2 patients showed numbness on the lateral thigh of the affected side, and the symptoms were relieved after symptomatic treatment. Four patients were found to have internal fixation screws loosening during follow-up, but still achieved good fracture healing.Conclusion:The entire hemipelvic ring could be exposed through LRA without cutting the peritoneum, so that the sacroiliac joint, ilium wing and anterior ring fractures could be reduced under direct version. In the treatment of pelvis fragility fractures of the elderly, effective reduction and fixation could be achieved using reconstruction plates or channel screws through LRA.

Objective:To investigate the surgical technique and the clinical effects of direct posterior approach (DPA) with the fixation of percutaneous tunnel screw and plate for acetabular posterior comminuted fractures.Methods:Thirty-six cases with acetabular posterior comminuted fractures treated by this technique from January 2016 to July 2020 were retrospectively analyzed in this study. There were 28 males and 8 female, aged 42.0±12.1 (range 19-64) years. According to Letournel-Judet classification, there were 28 cases of transverse associated with posterior wall fractures, 6 cases of posterior column with posterior wall fractures and 2 cases of T shape with posterior wall fractures. DPA was adopted in prone position. The anterior and posterior column fractures of the acetabulum were reduced under direct vision and then fixed with percutaneous tunnel screw. Further, the posterior wall fractures of the acetabulum were reduced and fixed with plate and screws. The operation duration, intraoperative blood loss, incision length, fracture union time, fracture reduction quality, postoperative complications and hip function were recorded.Results:The incision was 9.8±1.2 (range 8-12) cm. The operation duration was 102.9±21.4 (range 65-145) min. Intraoperative bleeding was 214.0±116.9 (range 100-640) ml. Postoperative X-ray and CT examinations showed perfect reduction. All the patients were followed up for 20.9±9.2 (range 10-38) months. The fracture healing time was 4.6±1.0 (range 3-6) months. There was no patient with damaged superior gluteal nerve and blood vessel. There were 2 cases of femoral head cystic changes without pain in walking, 1 case of postoperative infection and bacteremia who was cured at 1 month after debridement and anti-infection treatment, 1 case of sciatic nerve injury but recovered at 3 months after operation, and 1 case of heterotopic ossification at 3 months after surgery without affecting hip motion. According to the Matta's criteria, the reduction quality of the acetabular fracture was rated as excellent in 28 cases, good in 6 cases, fair in 2 cases. According to the modified Merle D'Aubigné and Postel scoring system, hip joint function was excellent in 24 cases, good in 10 cases and fair in 2 cases.Conclusion:DPA approach can directly reduce acetabular posterior comminuted fractures through a minimal incision. Combined with the technique of percutaneous tunnel screw, it displays great advantages of less trauma and with good clinical effects.