Piezo1 is a mechanosensitive ion channel protein widely expressed in mammalian cells with the function of sensing mechanical stimuli and of mediating signaling,and is embedded in the membranes of erythrocytes,the major cellular component of blood.Piezo1 regulates the morphology and function of erythrocytes by mediating the in-flux of Ca2+into the cell in crosstalk with the Gardos channel(KCa3.1),constituting the"Piezo1-Ca2+-Gardos channel axis".However,when Piezo1 is abnormally expressed or over-activated by its specific agonist(Yoda1),it can also lead to abnormal erythrocyte morphology and dysfunction,and even cause the development of related he-reditary diseases.

Objective:To establish the normal reference value of lumbar bone mineral density (BMD) under quantitative CT (QCT) in Chinese healthy adult females and to explore the regional differences.Methods:Total of 35 431 healthy women who met the inclusion criteria of Chinese health quantitative CT big data program were selected in this study. The BMD of the central plane of L 1 and L 2 vertebrae was measured by Mindways′s QCT system, and the mean value was taken. One-way analysis of variance was used to compare the BMD differences of lumbar vertebrae in women of different ages and regions. The subjects were grouped by an age interval of 10 years, and the level of BMD in different regions of the same age group were compaired. Results:The peak BMD of Chinese healthy adult women appeared in the age group of 20-29 years (Northeast China(183.01±24.58) mg/cm 3, North China (188.93±24.80) mg/cm 3, East China (187.54±27.71) mg/cm 3, South China (186.22±33.72) mg/cm 3, Central China (176.33±24.91) mg/cm 3, Southwest China(182.25±28.00) mg/cm 3), and then it decreased with age. The level of BMD in different regions decreased with the age. Before the age of 70 years, BMD in Central and Southwest China was always at a low level((176.23±24.91) to (90.38±28.12) mg/cm 3, 182.25±28.00 to (88.55±25.68) mg/cm 3), lower than those in Northeast China ((183.01±24.58) to (99.69±27.85) mg/cm 3), North China ((188.93±24.80) to (95.89±26.12) mg/cm 3), East China ((187.54±27.71) to (95.65±27.86) mg/cm 3). After 70 years of age, BMD tended to be the same in different regions ( P>0.05). The BMD values in Central China and Southwest China were similar in the age group of 40-60 years ( P>0.05). The BMD values in the health adult femles in the age group of 60 years in different regions of Chinawere all lower than those of bone mass abnormality (all P<0.05). The detection rate of osteoporosis in females over 50 years was the highest in Southwest China (25.65%) and it was the lowest in North China (17.30%). Conclusions:This study establishes reference values of BMD under QCT in healthy Chinese women, which can be used as a reference basis for identifying women with low BMD who are at risk of osteoporosis. The BMD value is the lowest in Southwest China and the highest in South China.

Objective:To study the application of establishing WeChat group combined with PBL teaching mode in the practice of pediatric orthopaedics.Methods:The study was conducted among 36 postgraduates of "5+3" pediatrics and 22 postgraduates of orthopedic surgery of Batch 2012 who had practice in Department of Orthopaedics, Children's Hospital of Chongqing Medical University from September 2018 to August 2019, and they were randomized into control group and experimental group, with 29 students in each group. The control group was taught by traditional PBL mode, while the experimental group was taught by WeChat group combined with PBL mode. At the time of leaving the department, the two groups were assessed by theoretical knowledge, practical operation and questionnaire satisfaction, thus evaluating the teaching effects. The SPSS 23.0 was used to conduct t test and chi-square test. Results:The average scores of theoretical knowledge test (91.28±2.89) and practical operation test (87.44±2.94) in the experimental group were significantly higher than those in the control group (87.39±3.53) and (79.06±3.84), with statistically significant differences ( P<0.05). In the survey of teaching satisfaction, the experimental group[96.55%(27/29)] was significantly higher than the control group[61.90%(21/29)], with statistically significant differences ( P<0.05). Conclusion:The establishment of WeChat group and the combination of PBL teaching model can significantly improve the teaching effect and students' satisfaction in the practice of pediatric orthopaedics, which is worthy of further promotion and application.

Objective:To study the differences in the cumulative dose between deformable image registration (DIR) and simple dose-volume histogram (DVH) summation in the fractionated brachytherapy of cervical cancer, and to analyze the feasibility of the application of DIR in the dosimetry assessment of targets and organs-at-risk (OARs) in the brachytherapy.Methods:A retrospective analysis was conducted for 13 cases with primary cervical cancer treated with four fractions of interstitial brachytherapy guided by CT images. The four CT images of each cases were registered using an intensity-based DIR. Then, the cumulative doses (the D2 cm 3, D1 cm 3, and D0.1 cm 3 of the bladder, rectum, intestine, and colon and the D90for targets) after DIR were calculated and compared to those obtained using simple DVH summation. Afterward, the correlation between the dose difference and dice similarity coefficient (DSC) was analyzed. With the dose difference (the remaining dose of OARs caused by the DIR) as limits, a new plan was made for the latest CT to calculate the dose increase to targets. Results:Compared to simple DVH summation, DIR allowed the cumulative doses of the D2 cm 3 and D1 cm 3 of bladder to be decreased by (2.47±1.92) and (2.82±2.73) Gy, respectively on average ( t=-3.65, -2.93, P < 0.05), those of the D2 cm 3, D1 cm 3, and D0.1 cm 3 of rectum to be decreased by (2.05 ± 1.61) Gy, (1.51 ± 1.58), and (3.21 ± 2.50) Gy, respectively on average ( t=-4.02, -3.02, -4.06, P < 0.05), and those of the D2 cm 3, D1 cm 3, and D0.1 cm 3 to be decreased by (1.42 ± 0.99), (1.55 ± 1.28) Gy, and (2.43 ± 1.95) Gy, respectively on average ( t=-3.52, -2.96, -3.06, P < 0.05). There was no significant statistical difference in the D90 of targets, the D0.1 cm 3 of the bladder, and the D2 cm 3, D1 cm 3, D0.1 cm 3 of the colon ( P > 0.05) between both methods, and there was no distinct correlation between DSC and dose difference ( P > 0.05). The DIR increased the dose to targets, with a median value of 150 cGy. However, the accuracy of the DIR should be improved. Conclusions:In clinical practice of multiple fractions of brachytherapy for cervical cancer, it′s still recommended to adopt the simple dose summation method to assess the doses to targets and OARs.

Objective:To explore the performance of the commonly used whole blood C-reactive protein (CRP) detection systems and give related recommendation on the performance requirements of detection systems.Methods:A total of 7 540 venous blood samples from 26 maternal, child and children′s hospitals were collected to conduct this multi-center study on the analytical performance of 5 commonly used whole blood CRP detection systems from March to April in 2019. The blank check, carryover, repeatability, intermediate precision, linearity, sample stability, influence of hematocrit/triglyceride/bilirubin, comparison with SIEMENS specific protein analyzer and trueness were evaluated. The 5 systems included BC-5390CRP autohematology analyzer, AstepPLUS specific protein analyzer, Ottoman-1000 Automated Specific Protein POCT Workstation, i-CHROMA Immunofluorometer equipment Reader and Orion QuikRead go detecting instrument. The 5 systems were labeled as a, b, c, d and e randomly.Results:Within the 5 systems, all values of blank check were less than 1.00 mg/L, the carryovers were lower than 1.00%. The repeatability of different ranges of CRP concentrations including 3.00-10.00, 10.00-30.00 and>30.00 mg/L were less than 10.00%, 6.00% and 5.00%, respectively, and the intermediate precision was less than 10.00%. The linearity correlation coefficients of the 5 systems were all above 0.975, while the slope was within 0.950-1.050. Whole blood samples were stable within 72 hours both at room temperature (18-25 ℃) and refrigerated temperature (2-8 ℃). The CRP results were rarely influenced by high triglyceride or bilirubin, except for the immmunoturbidimetric test based on microparticles coated with anti-human CRP F(ab) 2 fragments. When triglyceride was less than 15.46 mmol/L, the deviation of CRP was less than 10.00%. When bilirubin was less than 345.47 μmol/L, the deviation of CRP was less than 10.00%. CRP was more susceptible to Hct on the systems without Hct correction. The deviation of CRP between different Hct dilution concentration and 40% dilution concentration can reach as high as 67.48%. The correlation coefficients ( r) of 5 systems were all more than 0.975 in the range of 0-300.00 mg/L compared with Siemens specific protein analyzer. All systems passed the trueness verification using the samples with specified values of 12.89 and 30.60 mg/L. Conclusion:The performance of 5 systems can basically meet the clinical needs, but it is suggested that the whole blood CRP detection system without automatic Hct correction should be modified manually.

Objective:To establish a dosimetric method based on the well-chamber to verify the accuracy of the source positioning and dwelling time for the afterloading machine, aiming to provide a new method for the quality control of afterloading machine.Methods:The principle of this method was explained according to the hardware structure of the well-chamber. Then, the precision of this method was analyzed by the simulation test and data fitting. The feasibility test was also performed. And the advantages and disadvantages of this method were compared with those of the traditional method.Results:The precision of this method for detecting the source positioning was 0.07 mm and the dwelling time was 0.09 s, respectively. In the feasibility test, the standard deviation of the measure value was below 3%.Conclusions:The well-chamber method has high precision and convenient operation. It can be applied in the rapid verification of the relative accuracy of the source positioning and dwelling time of well-chamber.

Objective: To study the feasibility of using the PTW729 2D array ion-chamber to verify the relative dose distribution calculated with the Acuros BV algorithm. Both advantages and disadvantages of the method were analyzed to provide reference for practical clinical practices. Methods: Based on self-built measurement phantoms, the dose distribution on the same slice of the phantom was measured with PTW729 and film, respectively, under the same measurement condition and plan. The dose distributions obtained by the two method were compared with the result calculated with Acuros BV, separately, by using γ analytical tool. And the stability of the PTW729 was tested. Results: The γ comparison value was 95.9% between the film and Acuros BV, 98.9% between the PTW729 and Acuros BV and 88.0% between the film and PTW729, with 95.0%, 100.0%, and 100.0%, in their stability test respectively. Conclusions PTW729 2D array ion-chamber can be applied to the rapid verification of Acuros BV algorithm-calculated relative dose distribution.

Objective To investigate the clinical efficacy of open reduction and internal fixation with K-wires for old Gartland Ⅲ supracondylar fracture in children.Methods A retrospective case series study was conducted on 49 children with old Gartland Ⅲ supracondylar humeral fracture admitted from June 2012 to January 2017.There were 35 boys and 14 girls,with average age of 6.1 years (range,3.4-11.5 years).The duration from initial trauma to operation ranged from 22 days to 60 days (mean,29.8 days).There were five cases of radial nerve injury,one case of median nerve injury,and one case of Volkmann ischemic contracture.All patients were surgically treated with open reduction and internal fixation with K-wires + plaster external fixation.Six patients with nerve injury underwent neurological exploration and release.Nerve partial fracture was seen in one patient during operation,and nerve repair was performed.The fracture healing and complications were observed.At the final follow up,Flynn's criteria was applied to evaluate the elbow joint function.The humerus length and transverse diameter of humeral condyle between the healthy limb and the suffered one were compared to evaluate the humerus growth.Results All patients were followed up for 6-24 months,with an average of 12.5 months.All fractures were healed,with no fracture redisplacement or bone nonunion occurred.The neurological symptoms of six patients with nerve injury disappeared after two months.One patient had superficial skin infection at the incision and recovered after treatment.Six patients (12％) developed cubitus varus deformity after operation.At the final follow-up,the clinical and radiographic outcomes were assessed via Flynn's criteria,and the results were excellent in 37 patients,good in five,fair in one,and poor in six patients,with an excellent and good rate of 86％.There were no significant differences in the humerus length [(189.3 ± 27.8) mm vs.(190.6 ± 28.8) mm] and transverse diameter of humeral condylar [(29.5 ± 3.5) mm vs.(29.7 ± 3.6) mm] (P ＞ 0.05) between the healthy limb and the suffered one,respectively.Conclusion For old Gartland type Ⅲ supracondylar humeral fracture in children,open reduction and internal fixation with K-wires + plaster external fixation can attain satisfactory function recovery of elbow joint and reduce the incidence of cubitus varus deformity,without negative influence on children's humerus growth or development.

Objective To compare the clinical effect of tensile band wire fixation and plate fixation for treating children with olecroanon fracture.Methods Sixty-three children with olecroanon fracture at Children's Hospital of Chongqing Medical University from January 2006 to January 2014 were selected.In those cases of fracture by means of open reduction,41 cases were treated with tensile band wire,and 22 cases were treated with internal fixation with anatomical plate.Operation time,bleeding during operation,recovery time postoperatively,postoperative complications and joint function recovery were analyzed by using independent sample t-test and chi-square test.Results In the group of tensile band wire,there was no case of Kirschner wire loosening and displacement fracture.In group of steel plate,there were 2 cases of myositis ossificans.In the 2 groups,there was no case of bone nonunion.The average operation time:plate fixation group was (65.3 ± 8.4) min and tension band wire group was (58.4 ± 12.6) min,and there was a significant difference between the both groups (t =7.419,P ＜ 0.05);blood loss:plate fixation group was (5.3 ±0.8) mL and tension band wire group was (4.7-± 1.2) mL,and there was a significant difference between the both groups (t =2.595,P ＜ 0.05);fracture healing time:plate fixation group was (74.1 ± 8.4) d and tension band wire group was (61.7 ±9.3) d,and there was a significant difference between the both groups (t =10.636,P ＜0.05).With Broberg-Morrey to evaluate two groups'quality rate of function recovery,there was no significant difference in statistics with 85.3％ (35/41 cases) in tensile band wire group and 81.8％ (17/22 cases) in steel plate group(x2 =0.651,P ＞ 0.05).Conclusions Olecranon fracture in children using tension band wire fixation may be a better way,more suitable for promotion and implementation at basic hospital.

Objective To review the effect of exposed and buried Kirschner wire fixation of lateral humeral condyle fracture in children.Methods Randomized control trials (RCTs) about exposed versus buried Kirschner wire fixation of lateral humeral condyle fracture in children were identified through electronic search using the Cochrane Collaboration search strategies and manual search.Electronic database included Cochrane Library,Medline,PubMed,CBM,VIP,CNKI,Wanfang database and other Chinese and English database.Manual research included related journals and conference proceedings.Quality analysis of the included literatures was performed using the methodological index for non-randomized studies (MINORS).RevMan 5.3 software was used for Meta analysis.Results Four studies involving exposed Kirschner in 150 cases and buried Kirschner in 351 cases were included.The two techniques were similar with respect to postoperative infection (OR =1.10,95％ CI 0.52 ～ 2.33,P ＞ 0.05),superficial infection (OR =1.45,95 ％ CI 0.66 ～ 3.18,P ＞ 0.05),reoperation rate (OR =2.29,95％CI 0.51 ～ 10.25,P ＞0.05),delayed union rate (OR =1.57,95％ CI 0.76 ～ 3.21,P ＞0.05) and total complications (OR =1.57,95％ CI 0.76 ～ 3.21,P ＞ 0.05).However,Kirschner wire exposure shortened the time of pulling out Kirschner wire (MD =-13.28,95％ CI-16.42 ～-10.14,P ＜0.05).Conclusion Applied for lateral humeral condyle fracture in children,exposed versus buried Kirschner wire fixation results in short Kirschner wire stabilization time that avoids local anesthetic and cost while pulling out Kirschner wire in the late stage.