Shiga toxin 2 (Stx2) toxoid produced by formaldehyde treatment of purified toxin was used to immunize BALB/c mice for monoclonal antibody (MAb) production.The neutralizing activities of positive clones against Stx2 were screened by in vitro cytotoxicity assay.The isotype and specificity of resultant clone was determined,and its efficacy to neutralize the activity of purified Stx2 was evaluated by in vitro and in vivo toxicity model.Lastly,its spectrum of activity against Stx2 variants was also accessed by mouse toxicity model.It was demonstrated that one of the 12 positive MAb clones against Stx2,designating $2C4 had neutralizing activity.S2C4 belongs to the immunoglobulin G1 subclass and has a K light chain,and it reacts with the A subunit of Stx2 and does not bind to Stx2 B subunit or to Stx1.S2CA could efficiently neutralize the cytotoxicity of Stx2 to Veto cells and mice.It also protected mice against lethal doses of Stx2 variants challenge including Stx2c and Stx2vha.S2C4 is a promising candidate molecule in preventing the progression of hemolytic-uremic syndrome (HUS) mediated mainly by Stx2 in Stx-producing Escherichia coli(STEC)infection.

Objective To observe the results of treatment by open reduction and humeral head replacement for proximal humeral fracture-dislocation. Methods According to Neers classification, the cases included two-part proximal humeral fracture-dislocation 15 cases, three-part proximal humeral fracture-dislocation 29 cases, and four-part proximal humeral fracture-dislocation 21 cases. Fifty-four patients received T shaped steel plate and 11 patients received humeral head replacement. Early rehabilitation was started postoperatively. Results Fifty-four patients who received T shaped steel plate were followed up from 1 to 5 years (in average of 2.5 years), final results of all the patients were evaluated according to the HUANG Gong-yi′s criterion. The rate of excellent or good in patients of two-part fracture-dislocation were 100%, three-part fracture-dislocation was 79%, humeral head necrosis was 25%, four-part fracture-dislocation was 60%, and humeral head necrosis was 53%. Eleven patients who received humeral head replacement were followed up from 6 months to 5 years (in average of 1.5 years). According to SSMH of UCLA, the average score was 25.6. Score was above 27 in 1 case, 24~27 in 8 cases, 18~ 23 in 2 cases, less than 18 in 0. These cases were with an excellence rate of 82%. Average score was 9.0 in pain, 8.2 in function and 7.5 in muscle power. Conclusions T shaped steel plate to treat the two-part proximal humeral fracture-dislocation is effective in the functional recovery of the shoulder joint, but the rate of satisfaction as well as the necrosis in the three-part and four-part is poor. Satisfactory results can be obtained in humeral head replacement for the treatment of proximal humeral fractures especially for the treatment of three and four-part fracture-dislocation.

Background and purpose:The incidence of thyroid cancer (TC) is increasing worldwide. However, there were some differences among different regions. The purpose of this study was to investigate the incidence trends and clinicopathological characteristics of TC in Qingdao, a typical eastern coastal city, and to analyze the change in etiological spectrum of surgical thyroid diseases in recent years.Methods:A total of 2 251 patients who underwent thyroidectomy in 2014 due to thyroid nodules at the Affiliated Hospital of Qingdao University were retrospectively reviewed. The clinico-pathological characteristics were further analyzed among 1 306 patients with TC and compared with the corresponding data from the Surveillance Epidemiology and End Results (SEER) database as well as previous data from this hospital.Results:With the increasing number of thyroidectomy in Qingdao, there was also an increase in the proportion of TC in patients after thyroidectomy, from 34.8% in 2010 to 59.0% in 2014. Among those with TC, the male-to-female ratio was 1∶2.80, with a relatively high incidence among 20-54 year-old adults, who were younger than those reported in terms of distribution of age in SEER database (U=2 289,P=0.000). About 50.2% of the TC patients were overweight or obese, 78.2% TC patients had only asymptomatic nodules detected by ultrasound at initial diagnosis, while 16.6% had visible or palpable thyroid nodules. Only 5.2% presented hoarseness or other repression symptoms. Micro-carcinoma accounted for 61.7% of TC in 2014 at this hospital, which was significantly higher than the proportion in 2010 (37.7%). Lymph node involvement was significantly more frequent at this hospital than in SEER database (49.5%vs 26.0%,χ2=11.806,P=0.001). Even among patients with micro-carcinoma, 31.3% already presented lymph node metastases. The proportions of papillary, follicular, medullary and anaplastic carcinoma were 97.5%, 1.1%, 1.0% and 0.5%, respectively, among which the percentage of papillary carcinoma was higher than that in SEER database (U=4 654.5,P=0.055).Conclusion:There was an increase in the number of thyroidectomy in Qingdao, and the preoperative diagnostic accuracy of TC in this area kept rising. The in-cidence of TC was relatively high in a younger population, with more common lymph node involvements and an overweight trend. The increasing proportion of micro-carcinoma might be related to the popularization of health examination. However, the frequent lymph node metastasis in patients with micro-carcinoma is an important indicator of the invasive behavior of micro-carcinoma, which should not be overlooked.

Objective To purify Shiga toxin Ⅱ (STX Ⅱ) of enterohaemorrhagic Escherichia coli (EHEC) O157: H7 by affinity chromatography, and characterize its biological function. Methods The immno-affinity chromatography column was prepared by STX Ⅱ A subunit-specific antibody S1D8 coupling to Sepharose 4B matrix. The purity and specificity of STX Ⅱ molecule secreted by EHEC O157:H7 were detected by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and Western blot, respectively. The purified toxin was serially diluted and the toxic activities to Vero cell line and mice were observed. The 50% cytotoxic dose (CD50) for Vero cell line and 100% lethal dose (LD100) for mice were calculated. The protection effect of anti-STX Ⅱ polysera to the mice against the purified toxin challenge was also observed. Results STX Ⅱ was successfully purified from culture supernatant of EHEC O157:H7 using affinity chromatography scheme. The relative molecular weights of STX Ⅱ A and B subunits were 32 000 and 7 500 confirmed by SDS-PAGE, respectively. The purified toxin could react with monoclonal antibodies against STX Ⅱ A and B subunits, respectively.The toxin was cytotoxic to Vero cell with CD50 of 20 ng/L and lethal to mice with LD100 of 5 ng.The toxin could be neutralized by anti-STX Ⅱ polysera in vivo. Conclusion STX Ⅱ is successfully purified and its toxic effects are confirmed in both cell line and mouse model.

Objective:To investigate the clinical effect of Ilizarov bone transport technique with assisted guiding pin in medullary cavity for treatment of posttraumatic bone defect of tibia.Methods:A retrospective case series study was conducted to analyze the clinical data of 17 patients with post-traumatic bone defect of tibia admitted to Third Hospital of Hebei Medical University form November 2014 to March 2018.There were 13 males and 4 females, aged 19-60 years [(37.2±13.4)years]. The bone defect length was 4.6-14.0 cm [(8.6±2.8)cm] after debridement. All patients underwent treatment with Ilizarov bone transport technique. The alignment of transport bone segment was controlled by a guiding pin in medullary cavity of tibia. Bone grafts were performed to accelerate fracture healing of docking point. The wound healing, bone healing, external fixation time, external fixation index (EFI), alignment recovery were recorded. Bone healing and functional results were evaluated according to the criteria given by Association for the Study and Application of the Method of Ilizarov (ASAMI). The complication was recorded according to Paley's criteria. The physical component summary score (PCS) and mental component summary score (MCS) ware recorded according to the MOS 36-item Short-form Health Survey (SF-36) questionnaire and compared with the national norm to evaluate the quality of life.Results:After removal of the apparatus, follow-up period was 12-37 months [(29.9±4.4)months]. Wound healing was achieved without flap transfer. At the latest follow-up, all patients achieved bone healing without recurrent infection. External fixation time was 242-801 days [(436.5±154.6)days] and external fixation index was 35.7-60.5 d/cm [(50.6±6.2)d/cm]. The affected extremity alignment was restored in all patients except for residual angular deformity in one patient. According to ASAMI, the excellent and good rate of bony results and functional results were 88% and 94%. According to Paley's criteria, complications included 12 problems, 7 obstacles and 1 sequelae. The PCS and MCS in SF-36 questionnaire were (85.8±11.6)points and (69.6±11.1)points. Compared with the national norm [PCS: (87.6±16.8)points, MCS: (78.8±15.4)points], PCS showed no statistical difference ( P>0.05), but MCS showed statistical difference ( P<0.05). Conclusions:Ilizarov bone transport combined with intramedullary guiding pin can accelerate wound and fracture healing, control infection and restore lower limb alignment. The physical function of the affected extremity can be restored in spite of some complications and psychological effects. The technique is an effective treatment for posttraumatic bone defect of tibia.

Objective:To compare the efficacy of internal fixation using cannulated screw combined with fibular allograft and internal fixation using cannulated screw alone in the treatment of femoral neck fracture in young and middle-aged patients.Methods:A retrospective cohort study was conducted to analyze the clinical data of 75 young and middle-aged patients with femoral neck fracture admitted to the Third Hospital of Hebei Medical University from January 2020 to December 2022, including 44 males and 31 females, aged 34-56 years [(46.1±12.7)years]. According to Garden classification, 26 patients were classified as type II, 35 type III and 14 type IV. According to the Pauwels classification, 9 patients were classified as type I, 31 type II and 35 type III. Forty-nine patients were treated with internal fixation using three cannulated screws alone (cannulated screw group) and 26 with internal fixation using three cannulated screws combined with double-barrel fibular allograft (cannulated screw combined with bone grafting group). The operation time, intraoperative blood loss, length of hospital stay, and quality of fracture reduction were compared between the two groups. At 4, 8 months after operation and at the last follow-up, grading of femoral neck shortening, number of patients walking with crutches, Barthel index, and Harris hip function score were evaluated. The incidence of complications was measured at the last follow-up.Results:All the patients were followed up for 16-37 months [(23.2±4.5)months]. The operation time of the cannulated screw combined with bone grafting group was (86.3±16.1)minutes, longer than (76.9±20.8)minutes of the cannulated screw group ( P<0.05). The intraoperative blood loss was 100.0(50.0, 200.0)ml in the cannulated screw combined with bone grafting group, more than 50.0(50.0, 100.0)ml in the cannulated screw group ( P<0.01). There were no significant differences in the length of hospital stay or the quality of fracture reduction between the two groups ( P>0.05). At 4 months after operation, grading of the femoral neck shortening in the cannulated screw combined with bone grafting group [24 patients (92.3%) with grade 1, 2(7.7%) with grade 2, and 0(0.0%) with grade 3] was better than that in the cannulated screw group [18 patients (36.7%) with grade 1, 28(57.1%) with grade 2, and 3(6.2%) with grade 3] ( P<0.01). At 8 months after operation, grading of femoral neck shortening in the cannulated screw combined with bone grafting group [22 patients (84.6%) with grade 1, 3(11.5%) with grade 2, and 1(3.8%) with grade 3] was better than that in the cannulated screw group [13 patients (26.5%) with grade 1, 27(55.1%) with grade 2, and 9(18.4%) with grade 3] ( P<0.01). At the last follow-up, grading of femoral neck shortening in the cannulated screw combined with bone grafting group [19 patients (73.0%) with grade 1, 5(19.2%) with grade 2, and 2(7.6%) with grade 3] was better than that in the cannulated screw group [8 patients (16.3%) with grade 1, 31(63.2%) with grade 2, and 10(20.4%) with grade 3] ( P<0.01). At 4, 8 months after operation and at the last follow-up, 12(46.2%), 8(30.8%) and 5(19.2%) patients in the cannulated screw combined with bone grafting group and 38(77.6%), 27(55.1%) and 20(40.8%) patients in the cannulated screw group had to walk with crutches, respectively, showing significant difference between the two groups at the other two time points ( P<0.05 or 0.01) except for at the last follow-up ( P>0.05). The Barthel index values were 85.3±3.2, 90.3±4.3, and 95.3±3.9 in the cannulated screw combined with bone grafting group at 4, 8 months after operation and at the last follow-up, significantly higher than 80.8±7.3, 85.4±7.4, and 90.9±7.8 in the cannulated screw group ( P<0.05 or 0.01). The Harris hip scores were (87.0±2.9)points, (92.0±2.9)points and (91.3±2.4)points in the cannulated screw combined with bone grafting group at 4, 8 months after operation and at the last follow-up, significantly higher than (81.0±6.1)points, (85.7±5.8)points, and (89.6±2.0)points in the cannulated screw group ( P<0.01). At the last follow-up, the complication rate was 3.8%(1/26) in the cannulated screw combined with bone grafting group, significantly lower than 22.4%(11/49) in the cannulated screw group ( P<0.05). Conclusion:For femoral neck fractures in young and middle-aged patients, compared with internal fixation using cannulated screw alone, internal fixation using cannulated screw combined with fibular allograft has more advantages in correcting femoral neck shortening, restoring independent living activities and hip joint function, and reducing the incidence of complications despite its longer operation time and more intraoperative blood loss.