Preliminary experience of Bacillus Calmette-Guerin in the treatment of bladder cancer secondary to kidney transplantation / 中华泌尿外科杂志

Objective:To summarize the experience of Bacillus Calmette-Guerin(BCG) in the treatment of bladder cancer secondary to renal transplantation.Methods:The clinical data of 5 patients who underwent BCG bladder irrigation after secondary bladder cancer after kidney transplantation in Tianjin First Central Hospital from January 2015 to December 2019 were analyzed. There were 1 male and 4 female cases. During the period of immunosuppression after transplantation, 1 case developed secondary high-level non-muscular invasive bladder cancer (NMIBC), 3 cases developed secondary low-grade NMIBC, and 1 case developed secondary glandular cystitis (4 cases). The mean age of the 5 patients with secondary bladder cancer was 59.7±4.0 years. Case one with high level NMIBC was treated with transurethral resection of bladder tumor (TURBT) and postoperative irrigation of epirubicin. Case 3 and 5 with low-level NMIBC accepted regular postoperative irrigation of gemcitabine. No irrigative therapy was performed in case 2. Bladder cancer recurred in case 1, 2, 3 and 5 after 20.1±9.7 months. TURBT was observed in all the 4 patients, among which 3 were of high grade NMIBC and 1 was of low grade NMIBC. Four patients were irrigated with BCG 2 weeks after operation. Postoperative pathology indicated low-level NMIBC in case 4, and BCG was irrigated 2 weeks after the operation. During perfusion therapy, immunosuppressive agents were continued.Results:During BCG perfusion, 4 of the 5 cases showed BCG related local inflammation, among which 2 cases presented symptoms of bladder irritation, 1 case presented hematuria, and 1 case presented hematuria with low fever. Patients with frequent urination, pain in urine, hematuria and other symptoms improved after drinking plenty of water, taking bed rest and taking levofloxacin (0.5g/ day ×7 days). Patients with low fever were treated with antipyretic treatment. No antituberculous agents were used prophylactically during BCG perfusion. There were no symptoms of tuberculosis infection or sepsis. The function of transplantated kidney was normal and no tendency of rejection. The 5 patients were followed up for 7-24 months, 1 patient was lost to follow-up after 7 months of BCG bladder perfusion, and no tumor recurrence or metastasis was found in 5 patients during the follow-up.Conclusions:The use of immunosuppressive agents does not reduce the biological activity of BCG, and BCG does not increase the risk of systemic toxicity or affect the function of transplanted kidneys in immunocompromised patients. BCG is a treatment option for bladder cancer secondary to renal transplantation.

The efficacy of intravesical instillation of domestic BCG versus epirubicin in the prevention of recurrence of intermediate-risk or high-risk non-muscular invasive bladder cancer and predictive factors of BCG instillation: a randomized, controlled, multi-center clinical trial with 2 years’ follow-up / 中华泌尿外科杂志

Objective:To investigate the 2 years’ efficacy of intravesical instillation of domestic BCG versus epirubicin in the prevention of recurrence of intermediate-risk or high-risk non-muscular invasive bladder cancer and predictive factors of BCG instillation.Methods:From July 2015 to June 2020, 18-75 years old patients with moderate to high-risk non muscle invasive bladder cancer (NMIBC) confirmed by pathological examination were involved. The ECOG score was 0-2. Exclusion criteria included ①immune deficiency or impairment (such as AIDS), using immunosuppressive drugs or radiotherapy, suspected allergic to BCG or epirubicin or excipients of the two drugs, fever or acute infectious diseases including active tuberculosis or receiving anti tuberculosis treatment, with severe chronic cardiovascular and cerebrovascular diseases or chronic kidney disease; ②combined with other urogenital system tumors or other organ tumors; ③combined with muscle invasive bladder urothelial carcinoma (≥T 2); ④undergoing chemotherapy, radiotherapy or immunotherapy within 4 weeks (immediate instillation after surgery not included); ⑤ pregnant or lactating women; ⑥ comfirmed or suspected bladder perforation; ⑦gross hematuria; ⑧cystitis with severe bladder irritation that may affect the evaluation; ⑨participat in other clinical trials within 3 months; ⑩alcohol or drug addiction; ?any risk factors that may increasing the risk of patients. Epirubicin 50 mg was irrigated immediately after the operation(TURBT or laser resection). The patients were randomly divided into BCG15 group, BCG19 group and epirubicin group by the ratio of 2∶2∶1, and the patients were maintained intravescical instillation for 1 year. The recurrence and adverse events of the three groups were compared. Univariate and multivariate analysis was performed to predict the risk factors of BCG irrigated therapy failure. Result:By June 15, 2020, the median follow-up duration was 22.1 months(12.1, 32.3), and there was no statistical difference between the groups ( P=0.9024). There were 274 patients enrolled in BCG19 group, 277 patients enrolled in BCG15 group and 130 patients enrolled in the epirubicin group. The drop-off rate was 16.6%(113 cases)and made no difference between groups( P=0.6222). There were no significant difference in age, gender, BMI, or ECOG score( P>0.05). During the follow-up, 116 cases was detected recurrence or progression. The recurrence rate of the three groups was 14.2% and 14.8% in BCG19 group and BCG15 group, and 27.7% in the epirubicin group. There was no difference in recurrence rate between BCG19 and BCG15 group( P=0.9464). The recurrence rate of BCG19 group was lower than that of the epirubicin group ( P=0.0017). The recurrence rate of BCG15 group was lower than that of the epirubicin group ( P=0.0020). There was no difference in the cumulative recurrence free survival rate between BCG19 and BCG15 group (95% CI0.57-1.46, P=0.7173). The cumulative recurrence free survival rate of BCG 19 group was better than that of the epirubicin group( HR=0.439, 95% CI0.26-0.74, P=0.0006), and the cumulative recurrence free survival rate of BCG15 group was better than that of the epirubicin group ( HR=0.448, 95% CI0.29-0.80, P=0.0021). The total incidence of adverse events in 19 BCG19, BCG15 and epirubicin group were 74.5%, 72.6% and 69.8% respectively. There was no difference in the incidence of adverse events between BCG19 and BCG15 group( P=0.6153). The incidence of adverse events in epirubicin group was lower than that of BCG19( P=0.0051) and BCG15( P=0.0167) groups.There was no significant difference in the incidence of serious adverse events (SAE) among the three groups ( P=0.5064). Log rank test univariate analysis and Cox risk regression model multivariate analysis showed that the history of bladder cancer recurrence( HR=6.397, 95% CI1.95-20.94, P=0.0001)was independent risk factor for BCG irrigation failure. Conclusions:The 2 years’ efficacy of intravesical instillation of domestic BCG is better than than of epirubicin with good tolerance and safety. There is no difference between BCG19 and BCG15 group. BCG doesn’t increase SAE compared with epirubicin. Recurrence status was an independent prognostic factor regarding recurrence-free survival.

The research progress on positive margins of nephron sparing surgery for renal cell carcinoma / 中华泌尿外科杂志

Nephron sparing surgery ( NSS ) has become the standard treatment of small renal cancer . NSS have the similar curative effect compared with radical nephrectomy and preserve the kidney fuction. However, positive surgical margins after NSS is increasing and has attracted more and more attention. We will discuss positive surgical margins related factors and how to reduce the positive surgical margins in this review.

Effect of partial nephrectomy with positive margin on recurrence and metastasis in patients with renal cancer: a Meta-analysis / 中华泌尿外科杂志

Objective@#Systematic assessment of the effect of positive margin on recurrence and metastasis in patients with renal cell carcinoma who underwent partial nephrectomy.@*Methods@#The literature were searched on the rate of recurrence and metastasis in patients with positive margin and partial nephrectomy published in PubMed, Embase, Cochrane, China Biomedical Literature Database, China Knowledge Network, VIP Chinese Science and Technology Journal Database, and Wanfang Chinese Database up to December 2018. The quality of the literature included in this study was evaluated by two reviewers, and a meta-analysis was performed on the literature that met the inclusion criteria using the Revman 5.0 statistical software provided by Cochrane Collaboration.@*Results@#A total of seven articles were included, six of which were case-control studies, and the other one was a cohort study. These seven articles consisted of 6 928 patients, including 407 positive margins and 6 521 negative margins. For recurrence and metastasis, 407 positive margins were composed of 25 recurrences and 21 distant metastases, while 6 521 negative margins consisted of 68 recurrence and 96 distant metastasis. The disease-free survival rate of patients with positive margins is lower than that with negative margins (OR=4.92, 95%CI 2.66-9.08, P<0.001). The results of subgroup analysis of patients with recurrence and metastasis based on positive margin exhibited that positive margin increased the risk of recurrence in patients undergoing partial nephrectomy (OR=5.05, 95%CI 2.06-12.37, P<0.001), as well as the risk of metastasis (OR=3.70, 95%CI 2.18-6.26, P<0.001). Since different studies consisted of patients with different tumor staging, a stratified analysis was conducted and the disease-free survival rate of patients with positive margins decreased compared with that of negative margins (OR=4.13, 95%CI 2.54-6.70, P<0.001), although there were differences in the staging of tumor patients included in different studies, which did not weaken the results.@*Conclusions@#Positive margins increase the risk of recurrence and metastasis in patients undergoing partial nephrectomy.

Effect of partial nephrectomy with positive margin on recurrence and metastasis in patients with renal cancer: a Meta-analysis / 中华泌尿外科杂志

Objective Systematic assessment of the effect of positive margin on recurrence and metastasis in patients with renal cell carcinoma who underwent partial nephrectomy.Methods The literature were searched on the rate of recurrence and metastasis in patients with positive margin and partial nephrectomy published in PubMed,Embase,Cochrane,China Biomedical Literature Database,China Knowledge Network,VIP Chinese Science and Technology Journal Database,and Wanfang Chinese Database up to December 2018.The quality of the literature included in this study was evaluated by two reviewers,and a meta-analysis was performed on the literature that met the inclusion criteria using the Revman 5.0 statistical software provided by Cochrane Collaboration.Results A total of seven articles were included,six of which were case-control studies,and the other one was a cohort study.These seven articles consisted of 6 928 patients,including 407 positive margins and 6 521 negative margins.For recurrence and metastasis,407 positive margins were composed of 25 recurrences and 21 distant metastases,while 6 521 negative margins consisted of 68 recurrence and 96 distant metastasis.The disease-free survival rate of patients with positive margins is lower than that with negative margins (OR =4.92,95％ CI 2.66-9.08,P ＜ 0.001).The results of subgroup analysis of patients with recurrence and metastasis based on positive margin exhibited that positive margin increased the risk of recurrence in patients undergoing partial nephrectomy (OR =5.05,95％ CI 2.06-12.37,P ＜0.001),as well as the risk of metastasis (OR =3.70,95％ CI 2.18-6.26,P ＜0.001).Since different studies consisted of patients with different tumor staging,a stratified analysis was conducted and the disease-free survival rate of patients with positive margins decreased compared with that of negative margins (OR =4.13,95％ CI 2.54-6.70,P ＜ 0.001),although there were differences in the staging of tumor patients included in different studies,which did not weaken the results.Conclusions Positive margins increase the risk of recurrence and metastasis in patients undergoing partial nephrectomy.

BK virus infection and urothelial carcinoma after renal transplantation / 中华器官移植杂志

Objective To explore the potential role of BK virus (BKV) in urothelial carcinoma after renal transplantation .Methods From May 2013 to March 2017 , We collected 26 cases of urothelial carcinoma after renal transplantation (study group) and 30 cases of urothelial carcinoma of non-immunosuppressed patients (control group) .Tumor tissues were stained with SV40 T antigen by immunohistochemical assay .Urinary and peripheral blood samples were assayed for BKV-DNA levels by real-time fluorescent quantitative polymerase chain reaction (PCR) .Results There were 7 positive cases of SV40 T-Ag in study group and only 1 weakly positive case in control group .The positive rate of BKV-DNA was 38 .5％ in urinary samples in study group (10 /26 ) and it was significantly higher than that in control group by 10％ (3/30)(P< 0 .05) .And the positive rate of blood BKV-DNA was not different between two groups ( P > 0 .05 ) .Conclusions There is a relatively high prevalence of BKV infection in urothelial carcinoma after renal transplantation .And a ,high level of BKV infection may play a role in urothelial carcinoma after renal transplantation .

A preliminary study on the expression of human leucocyte antigen G in urothelial carcinoma after renal transplantation / 中华泌尿外科杂志

Objective To investigate the expression of human leucocyte antigen G (HLA-G) in urothelial carcinoma after renal transplantation,and to analyse the relationship between HLA-G expression and the various clinical and pathological parameters.Methods 29 patients with urothelium carcinoma after renal transplantation for the first time from January 2005 to June 2016 were selected as the experimental group,the age range was 32-70 years,with an average of (55.5 ± 8.1) years.29 non-transplanted patients with urothelial carcinoma as the control group 1,the age range was 36-74 years,with an average of (57.9 ± 8.2) years.15 cases of normal urinary tract epithelial were from cystoscopy biopsy as the control group 2.Immunohistochemical method was used to detect the difference of HLA-G expression between the three groups.The clinical and pathological data of patients with urothelial carcinoma after renal transplantation were analyzed.Results The expression rate of HLA-G was 79.3％ (23/32) in patients with urothelial carcinoma after renal transplantation,37.9％ (11/32) in non-transplanted group and 0 (0/15) in normal urinary tract epithelium group.The expression rate of HLA-G in non-transplanted group was significantly higher than that in normal urinary tract epithelium group (P ＜ 0.05).The expression rate of HLA-G in patients with urothelial carcinoma after renal transplantation was significantly higher than that in nontransplanted group and normal urinary tract epithelium group (P ＜ 0.05).Conclusions HLA-G is associated with the occurrence of urothelial carcinoma after renal transplantation.It may provide a new idea for the prevention and treatment of urinary tract epithelium after renal transplantation.

Clinical analysis of 11 cases of urothelial carcinoma in the ipsilateral kidney transplant recipients / 中华器官移植杂志

Objective To explore the clinical characteristic,treatment,and prognosis of urological de novo malignant tumor in kidney transplant recipients.Methods A retrospective analysis was performed on 11 patients with urothelial carcinoma admitted in our institute between 2008 and 2016.Three patients were male and 8 patients were female.The interval between tumorigenesis and transplantation ranged from 12 to 132 months with a mean time of 68.4 months.Of the 11 cases,5 had pelvic TCC,4 cases had ureter TCC,and the rest 2 cases had pelvic and ureter TCC.All patients were in the same side of transplanted kidney (right).Of the 11 cases,7 had a main clinical manifestation of gross hematuria,3 cases had abdomen pain of the right side,and 1 case had hydronephosis of the right side during physical examination.Surgical treatment was taken in all 11 cases,combined with chemotherapy and irnmunotherapy (decreased immunosuppressive agents)treatment.Results Surgical treatment in all 11 cases was successful,and the postoperative pathology results confirmed the diagnosis of urothelial carcinoma.One patient receiving palliative treatment died 4 months after diagnosis.One patient died of extensive metastatic disease at 36th month postoperatively,and one patient died of respiratory failure.The rest 8 cases were followed for 4-96 months.One patient was given sirolimus (SRL) but diarrhea,so cyclosporine A (CsA) was administered.The renal function in the remaining 8 patients was normal.Conclusion Laparoscopic surgery combined with middle and small incision in the treatment of autologous ipsilateral urothelial carcinoma after renal transplantation is safe and effective.

Research advances in the correlation between DEK protein and oncogenesis / 中国肿瘤临床

DEK protein is an abundant chromatin protein in metazoans with highly conserved nuclear factor. This protein is a unique member of its family and is preferentially expressed in actively proliferating and malignant cells. Recently, much attention has been paid to the role of DEK protein in the development of various cancers, which was originally discovered in a subset of acute my-elogenous leukemia. Oncogene DEK is overexpressed in several malignancies including hepatocellular carcinoma, glioblastoma, retino-blastoma, bladder cancer, malignant melanoma, and cervical cancer. Oncogene DEK is a chromatin remodeling protein that supports cancer cell proliferation and invasion. In this review, we summarized research advancements in the correlation between DEK protein and oncogenesis.

A retrospective clinical study of urogenital fistula caused by gynecological and obstetrical surgery / 中华泌尿外科杂志

Objective To study the etiology,diagnosis,treatment and prophylaxis strategy of the urogenital fistula caused by gynecological and obstetrical surgery.Methods Data of 64 cases with urogenital fistula,who were admitted into second hospital of Tianjin medical university and Tianjin first central hospital from January 1992 to December 2012,were analyzed retrospectively.In Tianjin first central hospital,those cases include vesicovaginal fistula in 10,ureterovaginal fistula in 7 and urethro-vaginal fistula in one case.In second hospital of Tianjin medical university,those cases include vesicovaginal fistula in 26,ureterovaginal fistula in 18,urethro-vaginal fistula in 1 and ureterouterine fistula in one case.The median age was 42 years old (range 21-53).The history of diseased ranged from 16 days to 30 years.All patients were diagnosed by methylene blue test,cystoscopy,ureteroscopy,intravenous urography,ultrasound,computed tomography (CT) and magnetic resonance urography (MRU).The primary fistula was diagnosed in 50 cases and the recurrence was found in 14 cases.Single fistula existed in 56 cases and multiple fistulas were found in 8 cases.In 36 patients with vesicovaginal fistula,transabdominal repair of vesicovaginal fistula (n =20),transpubic surgery (n=10) and transvaginal surgery (n=6) were chosen.In 25 patients with ureterovaginal fistula,ureterocystostomy (n =10),ureterotomy with holmium laser (n =8),ureteral stent placement (n =6) and ureteral stricture excision and bladder-psoas suspension (n=1) were used.Two patients with urethro-vaginal fistulae were cured by the Latzko technique.One patient had uretero-uterine fistula and cured by ureteral stricture excision,ureterocystostomy and bladder-psoas suspension.Results Fifty-five(86％) cases were cured by single-stage surgical treatment and nine patients experienced more than two times of surgical treatment.The incipient patients have a higher success rate of first surgery than recurrent patients (92％ vs.64％,P＜0.05).Single and multiple fistulas have no significant difference about the surgical successive rate (88％ vs.75％,P＞0.05).In cases with vesicovaginal fistula,the success rate of vaginal and abdominal approaches are the same 85％ (P＞0.05).In cases with ureterovaginal fistula,abdominal and endoscopic approaches were 100％ and 85％,respectively (P＞0.05).The mean duration of follow was 20 months (range 3-48).There was no recurrence during follow-up.Conclusions Urogenital fistula caused by gynecological and obstetrical operation can be cured by surgery.Recurrent fistula is a challenge for diagnose and treatment,preoperative need reasonable operation mode to improve the success rate of operation.Both open surgery and endourology approaches are effective treatment options in management the urogenital fistula.

A comparison between 635/808 nm dual-wavelength semiconductor laser and He-Ne laser irradiation in the healing of surgical incisions / 国际生物医学工程杂志

Objective To compare healing effects of surgical incisions using 635 /808 nm dualwavelength semiconductor laser and He-Ne laser irradiation.Methods 168 cases of non-malignant tumor surgery patients were randomly divided into 2 groups:test group including 83 cases which were treated on the surgical incisions by laser irradiation of the semiconductor illumination with low-intensity power; positive control group with 85 cases treated with He-Ne laser.Observation was carried out on incision healing by the clinic manifestations including redness,heat,swelling,pain,exudation,wound open,adverse event and the incision length offset.Results There was no significant difference between experimental group and the control group on incision healing (P＞0.05).Conclusions The treatment efficacy of the dual-wavelength semiconductor laser on surgical incisions healing is similar with that of the He-Ne laser.

Effect of combined low dose Gemcitabine and Oxaliplatin in the treatment of advanced or metastatic urothelial carcinoma / 中华泌尿外科杂志

Objective To evaluate the therapeutic effect and toxicities of low dose Gemcitabine combined with Oxaliplatin in the treatment of advanced or metastatic uroedthelial carcinoma.Methods A total of 42 patients pathologically confirmed advanced or metastatic urothelial carcinoma (23 bladder cancer cases,11 ureteral carcinoma cases,and 8 renal pelvic carcinoma cases) were reviewed.Karnofsky score for each patient before treatment was more than 60.Combined treatment with Gemcitabine and Oxaliplatin regimen was as follows:Gemcitabine 700 mg/m2,iv infusion at day 1,8 and day 15,Oxaliplatin 100 mg/m2,iv infusion at day 2.The regimen was administered for more than 2 cycles (every 4 weeks) and the response rate was evaluated.The regimen was used in palliative chemotherapy and adjuvant chemotherapy,respectively.Results According to WHO evaluation criteria on therapeutic effectiveness,7 patients (16.7％) had complete response,13 patients (30.9％) had partial response,14 cases (33.3％) remained stable status,and 8 cases (19.1％) had progression.The overall response rate was 47.6％.The main side effects included thrombocytopenia,leucopenia,nausea,vomiting and alopecia,which were mild to moderate and disappeared when the chemotherapy was ceased.No chemotherapy related death occurred.Conclusions Combined treatment with low dose Gemcitabine and Oxaliplatin is effective for advanced or metastatic urothelial carcinoma,with mild and tolerable toxicities.

Hand-assisted retroperitoneal laparoscopic living donor nephrectomy with a modified technique / 中华泌尿外科杂志

Objective To evaluate the safety,feasibility and results of the hand-assisted retroperitoneal laparoscopic living donor nephrectomy ( HRPLDN ) with a modified technique. Methods Living donors (n =32) were divided into HRPLDN group (n =16) and open group (n =16) according to surgical technique.Operative data and postoperative outcomes including operative time,estimated blood loss,warm ischemia time,length of hospital stay and complication rate,were collected. Results All procedures were completed successfully.In HRPLDN group,the mean operative time was 101.3 ± 21.2 min (range from 70 to 150 min),with an estimated blood loss of 53.8 ±25.5 ml (range from 20 to 100 ml) and warm ischemia time of 2.4 ± 0.6 min ( range from 1.5 to 3.5 min).No living donor needed conversion to open surgery and the urine volume of transplanted kidney after first 24 hours was 5036 ml (range from 3500 -6500 ml).The mean postoperative on bed time were (2.8 ± 0.7 ) d (ranging from 2 -4 d).All parameters of HRPLDN were significantly better than that of open groups. Conclusion Living donor nephrectomy with HRPLDN is a safe and reliable surgical technique.

Development of urothelial tumors following renal transplantation of 11 cases report / 中国综合临床

Objective To analyze the incidence and clinical features of urothelial tumors in renal allograft recipients.Methods A retrospective analysis of 1042 patients received renal allografts who had taken immunosuppression for at least six months between 2006 and 2011 in The First Centre Hospital of Tianjin was performed.Results Eleven cases of uroepithelial tumors were diagnosed in the 1042 cases of renal transplantation ( 1.06％ ),of whom 9 cases were noticed by hematuria ( 81.8 ％ ),2 cases ( 18.2％ ) by medical examination.Six patients were diagnosed with multifocal urothelial carcinomas.Surgery was performed on all the patients with renal tumors and followed by chemotherapy or radiotherapy.Conclusion Malignancies in urinary tract after renal transplantation should be bore in mind.Early diagnosis is very important.The treatment options include reducing immunosuppressive agents and removing tumor lesions completely.

Impact mechanics properties of T3-12 thoracic vertebra cancellous bone: Comparison between the youth and elderly people / 中国组织工程研究

BACKGROUND:Impact mechanics properties of thoracic vertebra cancellous bone should be understood in treating osteoporosis,bone remodeling,bone reconstruction,as well as fixator selection for thoracic vertebral fracture.Most of previous studies concerning youth and the elderly bodies alone,reports regarding impact of thoracic vertebra cancellous bone mechanical properties are few.OBJECTIVE:To perform impact experiment to the normal people youth and the elderly fresh corpse thoracic vertebra cancellous bone to survey the impact mechanical properties,and to definite whether the impact mechanical properties of thoracic vertebra trabecular bone have difference between youth and the elderly people.METHODS:Experimental samples were from 4 normal fresh corpse,aged 20,25,70 and 75 years,were provided by Department of Anatomy,Norman Bethune Medical University.Spinal column thoracic vertebra T_(3-12) specimen were obtained from corpse within 1 hours and cut into 40 mm×6 mm×6 mm pieces,with 20 test pieces in each group.The impact experiment was performed using energy liberation method at room temperature under 28 ℃.After experiment,the impact energy was displayed automatic on testing machine,and the impact toughness was calculated by mechanical formula,and the morphology of fracture surface was observed.RESULTS AND CONCLUSION:The impact energy and impact toughness of the youth group was obviously greater than that of the elderly group (P＜0.05).Majority of the fracture surfaces were comminuted,minority were transverse or oblique fracture.The macroscopic observation showed that trabecular arranged compact in the thoracic vertebra cancellous bone of the youth group,which was sparse arrangement and presented with senile osteoporosis in the elderly group.It demonstrated that the impact mechanics properties of thoracic vertebra cancellous bone are different between the youth and elderly groups,and osteoporosis changes impact mechanics properties in the elderly people.

Shear mechanical properties of lumbar trabecular bone in aged people / 中国组织工程研究

BACKGROUND:Shear mechanical properties of lumbar trabecular bone should be understood in treating osteoporosis,bone remodeling,bone reconstruction,as well as the choice of fracture fixed equipment.OBJECTIVE:To explore whether the shear mechanical properties of lumbar trabecular bone is different in young and aged normal fresh cadavers.METHODS:Experimental samples were from 4 normal fresh corpse,aged 22,28,70 and 75 years,were provided by Department of Anatomy,Norman Bethune Medical University.Spinal column thoracic vertebra L_2-L_5 specimen were obtained from corpse within 1 hour and cut into 40 min×5 mm×5 mm pieces.The specimen were tested on electronic universal testing machine with speed of 5 mm/min,the shear load,stress,strain and other data would be printed automatically,and the morphology of fracture surface was observed.RESULTS AND CONCLUSION:Majority of the fracture surfaces were comminuted,minority were transverse or oblique fracture.The macroscopic observation showed that trabecular arranged compact in the thoracic vertebra cancellous bone of the youth group,which was sparse arrangement and presented with senile osteoporosis in the aged group.The shear force,shear stress and strain of the youth group was greater than that of the aged group[(37.19±3.25),(28.34±3.42) N;(1.49+0.13),(1.13±0.14) MPa;(1.40±0.50)%,(0.90±0.20)%,P＜0.05].It demonstrated that the impact mechanics properties of thoracic vertebra cancellous bone are different between the youth and aged groups.

Tensile mechanical properties of human tracheal cartilage / 中国组织工程研究

BACKGROUND:Tracheal injury suture and the development of a new tracheal prosthesis all need to understand the tensile mechanical properties of tracheal cartilage.so as to repair and rebuild tracheal function.Previous researches on the biomechanics of artificial trachea are many reported.while the biomechanics of human tracheal cartilage is reported less.OBJECTIVE:To investigate the mechanical properties of tracheal cartilage using one-dimensional tensile test method.METHODS:Two fresh cadaver specimens of normal human trachea.with the informed consents of their families.were involved.The specimens were thaw at room temperature,and then tracheal cartilage specimens were cut using scalpel into 20 samples at the length of 25 mm,width 5 mm,thickness 1.8-2.2 mm.The 20 tracheal cartilage samples were subjected to one-dimensional tensile test with Shimadzu electronic universal testing machine Japan,at the tensile test speed of 5 mm/min.The tensile maximum load,maximum displacement,maximum stress,maximum strain,elastic modulus and stress-strain curve of the specimens were observed.RESULTS AND CONCLUSION:The maximum load of human cadaver tracheal cartilage was(60 946±10.377)N,maximumdisplacementwas(1.973±0.159)mm,maximum stresswas(6.229±1.125)Mpa,maximum strainwas(32.825±2.776)%.Tracheal cartilage stress-strain curves was changed along with the index,the initial low slope of the curye was due to the direction of imposed tension was similar with the arrangement of collagen structure,the steep slope represented the tensile strength of collagen.To describe the tracheal cartilage stress-strain relationship in a one-dimensional tension,15 stress-strain data of the tracheal cartilage experimental data adopted polynomial by the least square fitting method,to obtain stress(δ)-strain(ε)relationship forrnula:σ(ε)=-0.111 3e~5+1.602 1e~4-7.821 6e~3+17.995 1e~2+3.624e.It is indicated that tracheal cartilage has a strong capacity to bear Joad and resist deformation,reflecting their viscoelastic mechanical properties of both flexibility and viscosity,supporting that the mechanical properties of cartilage is positively related to cartilage collagen content.

Creep characteristics of cancellous bone at 45°between normal and necrotic femoral head / 中国组织工程研究

BACKGROUND:The creep characteristics of cancellous bone from necrotic femoral head are important for clinical artificial joint replacement.Therefore,it is necessary to study mechanical properties of cancellous bone at 45°direction.OBJECTIVE:To compare creep properties of normal femoral head and necrotic femoral head at 45°direction based on three-parameter model established creep equation METHODS:A total Of 8 normal and 8 necrotic femoral heads were used.The cancellous bone was harvested at 45° and subjected to creep test on electronic universal testing machine.With simulated temperature field of human body temperature at36.5℃.stress was imposed on the samples by an increase of 5%/s for 7 200 seconds.100 experimental data were collected,and stress relaxation equation was calculated using three-parameter model.RESULTS AND CONCLUSION:The creep curve of the femoral head of normal and necrotic changes was exponential relation.Changes were fast in the first 600 seconds,and strain increased slowly with time,finally entered into balance stage.7 200 s creep of cancellous,bone from necrotic femoral head was less than normal femoral head cancellous bone.Three-parameter model calculation is simple and can well fit the creep of changes in the femoral head.The establishment of such idealized equation quantitatively shows poor visco-elasticity of the necrotic femoral head.

Biomechanical analysis of two fixation methods in treating spine fracture and dislocation / 中国组织工程研究

BACKGROUND:Thoracic or lumbar spine fracture and dislocation mainly treated by internal/external fixation devices with surgical methods.Fixation methods in treating spine fracture and dislocation is an important subject for scholars.OBJECTIVE:To quantitative analyze the treatment of spinal fracture and dislocation using pedicle screw and plate fixation,and to provide mechanical parameters for clinical application.METHODS:Shimadzu electronic universal testing machine was used to simulate L_1 lumbar fracture and dislocation treated by plate fixation and pedicle screw fixations,specimens were underwent flexion,extension,compression,as well as torsion tests,with speed of 5 mm/min.The torsion test was performed on the torsion machine with speed of 0.05 (°) / s.All the experimental data were analyzed by statistical analysis and paired t test.RESULTS AND CONCLUSION:The results demonstrated that the outcomes of compression test had no significant differences between 2 groups (P>0.05).The left and right torsion angle of the pedicle screw fixation group was smaller than that of the plate fixation group (P<0.05),and the flexion and extension displacements was smaller in the pedicle screw fixation group than in the plate fixation group (P<0.05).It suggested that plate fixation is worse than pedicle screw fixation,while pedicle screw fixation is conductive to bone healing,thus,pedicle screw fixation is a better internal fixation device.

The Mechanical Properties of Medial Collateral Ligament in Animal Model of Osteoarthritis / 医学研究杂志

Objective To compare the mechanical properties of animal knee lateral collateral ligament tensile between the normal and atherosclerotic animal model of osteoarthritis,and to identify if there are effects of osteoarthritis on the animal knee lateral collateral ligament tensile mechanical properties.Methods The experimental rats were provided by the Changchun High Medical Center for animal experiments.The 6-month-old male rats were the copying model of osteoarthritis.The tensile experiments at electron Shimadzu universal testing machine was carried out on ten of normal and pathological specimens.The speed of the tensile experiments was 5mm/min.Experimental data were processed by polynomial least square method.Results The tensile maximum load of normal control group was(26.12?4.00)N,maximum stress was(40.93?6.71)MPa,maximum displacement was(3.08?0.77)mm,and maximum strain was(9.51?2.36)%.The tensile maximum load of model group was(12.05?2.07)N,maximum stress was(21.28?4.17)MPa,maximum displacement was(2.32?0.56)mm,and maximum strain was(7.04?1.79)%.Conclusion The tensile performance of normal control group was significantly greater than that of the model group(P