Finite element analysis of cemented prostheses for hip replacement in elderly patients with comminuted intertrochanteric fracture.

BACKGROUND: To determine postoperative stress distribution after cemented arthroplasty in elderly patients with comminuted intertrochanteric fracture, and assist in determining a rational prosthetic stem length. METHODS: A three-dimensional (3D) model of intertrochanteric fracture was established using the Mimics and Unigraphics modeling software, which included the 3D model of comminuted intertrochanteric fracture, two long-stem(#4,#5) and one short stem(#3) prostheses, and the mantle layer of cement. The bone defect of the calcar femorale was replaced with a 5-mm thick cement. Then, the 3D finite element model of those materials was established, boundary conditions of force were imposed, and material parameters were set. Accordingly, a finite element analysis was performed to this model in stress. RESULTS: (1) The stress of the femur in the three-stem replacement prosthesis models increased from proximal end to distal end in the same pattern, while a stress concentration region was found at 5 mm from within the distal tip of the short-stem prosthesis (#3), which had a peak value of 67.85 MPa. However, no stress concentration was found on the long-stem prosthesis model. (2) For the short-stem prosthesis, the stress distribution of the cement-prosthesis interface was significantly concentrated in the distal region around the prosthesis end, in which the peak value of the lateral interface exceeded the fatigue strength of the bone cement. However, the biomechanics for the long prosthesis was better appreciated. CONCLUSION: Long prosthesis stems may theoretically be a better option for comminuted intertrochanteric fractures in elderly patients. However, the application of exceedingly long prosthesis stems would not be a better option. KEY WORDS: Comminuted intertrochanteric fracture, Elderly patients Finite element analysis, Prosthetic replacement.

Inhibitory effect of ursolic acid on proliferation of TPC-1 cells in thyroid carcinoma / 医学研究生学报

ObjectiveAt present, there are relatively few studies on the inhibitory effect of ursolic acid (UA) on the proliferation of thyroid cancer cells. This paper intends to explore the inhibitory effect and mechanism of ursolic acid on the proliferation of TPC-1 cells in thyroid papillary carcinoma.MethodsAfter adhering TPC-1 cells to the wall, the original medium was discarded and added ursolic acid medium without fetal bovine serum (0, 2, 4, 8, 16, 32 μmol/L, respectively, with 0 μmol/L as the control), and then the culture medium without cells was used as blank. The proliferation inhibition rate of TPC-1 cells was detected by CCK8 reagent at different times (24 h, 48 h); Flow cytometry was used to detect the apoptosis rate; JC1 kit was used to detect the changes of mitochondrial membrane potential (MMP) of TPC-1 cells after ursolic acid was applied; Fluorescent probe DCFH-DA was used to detect reactive oxygen species in TPC-1 cells after ursolic acid intervention; Flow cytometry was used to detect the protein expression of survivin and vascular endothelial growth factor (VEGF) in cells. RT-PCR assay detected the expression of survivin and VEGF mRNA in TPC-1 cells after the intervention of ursolic acid at different concentrations.ResultsThe inhibitory rate of 2, 4, 8, 16 and 32 mol/L ursolic acid on TPC-1 cells was significantly higher than that of 0 mol/L (P<0.01), and the inhibitory rate of 48 h ursolic acid on TPC-1 cells was significantly higher than that of 24 h (P<0.05). Therefore, the TPC-1 cell inhibition rate was positively correlated with ursolic acid concentration and the time (P<0.05). The apoptosis rates of 0 mol/L, 4 mol/L and 8 mol/L ursolic acid were (4.13±0.61)%, (6.53±0.65)% and (13.13±1.59)%, respectively. With the increase of the concentration, the apoptosis rate of TPC-1 cells increased gradually (P<0.05). The relative expression levels of survivin, VEGF protein and mRNA of 4 and 8 mol/L ursolic acid were significantly lower than those of 0 mol/L (P<0.05), and the expression levels of 8 mol/L ursolic acid was significantly lower than that of 4 mol/L (P<0.05).ConclusionUrsolic acid can effectively inhibit the proliferation and induce the apoptosis of TPC-1 cells, and its inhibitory induction pathway is related to the expression of survivin and VEGF in cells.

Effect of Cross-Linked Hyaluronate Scaffold on Cartilage Repair: An In Vivo Study.

OBJECTIVE: To determine the safety and effectiveness of a cross-linked sodium hyaluronate (CHA) scaffold in cartilage repair. METHODS: Physicochemical properties of the scaffold were determined. The safety and effectiveness of the scaffold for cartilage repair were evaluated in a minipig model of a full-thickness cartilage defect with microfracture surgery. Postoperative observation and hematological examination were used to evaluate the safety of the CHA scaffold implantation. Pathological examination as well as biomechanical testing, including Young's modulus, stress relaxation time, and creep time, were conducted at 6 and 12 months postsurgery to assess the effectiveness of the scaffold for cartilage repair. Furthermore, type II collagen and glycosaminoglycan content were determined to confirm the influence of the scaffold in the damaged cartilage tissue. RESULTS: The results showed that the routine hematological indexes of the experimental animals were within the normal physiological ranges, which confirmed the safety of CHA scaffold implantation. Based on macroscopic observation, it was evident that repair of the defective cartilage in the animal knee joint began during the 6 months postoperation and was gradually enhanced from the central to the surrounding region. The repair smoothness and color of the 12-month cartilage samples from the operation area were better than those of the 6-month samples, and the results for the CHA scaffold implantation group were better than the control group. Greater cell degeneration and degeneration of the adjacent cartilage was found in the implantation group compared with the control group at both 6 and 12 months postoperation, evaluated by O'Driscoll Articular Cartilage Histology Scoring. Implantation with the CHA scaffold matrix promoted cartilage repair and improved its compression capacity. The type II collagen level in the CHA scaffold implantation group tended to be higher than that in the control group at 6 months (2.33 ± 1.50 vs 1.68 ± 0.56) and 12 months postsurgery (3.37 ± 1.70 vs 2.06 ± 0.63). The GAG content in the cartilage of the control group was significantly lower than that of the experimental group (2.17 ± 0.43 vs 3.64 ± 1.17, P = 0.002 at 6 months and 2.27 ± 0.38 vs 4.12 ± 1.02, P = 0.002 at 12 months). Type II collagen and glycosaminoglycan content also demonstrated that CHA was beneficial for the accumulation of both these vital substances in the cartilage tissue. CONCLUSIONS: The CHA scaffold displayed the ability to promote cartilage repair when applied in microfracture surgery, which makes it a promising material for application in the area of cartilage tissue engineering.

Comparison of the minimally invasive treatments of laparoscopic and endosopic for common bile duct stones after gastrojejunostomy / 北京大学学报(医学版)

OBJECTIVE@#To explore the feasibility and to compare the merits and demerits of laparoscopic and endoscopic approach in removing common bile duct stones in patients with gastrojejunostomy after gastrectomy.@*METHODS@#Between January 2012 and December 2016, 25 patients with common bile duct stones after gastrojejunostomy received laparoscopic or endoscopic treatment in our centers. They were divided into laparoscopic group and endoscopic group based on treatment approaches for common bile duct stones, including 15 patients in laparoscopic group and 10 in endoscopic group. The clinical characteristics and outcomes between the two groups were retrospectively analyzed.@*RESULTS@#Among the 25 patients with gastrojejunostomy, the method of reconstruction was Billroth II in 21 patients and Roux-en-Y in 4 patients. Six patients received laparoscopic or endoscopic treatment during the acute cholangitis state. Among the laparoscopic group, 5 patients with stones more than 1 cm, 7 patients with multiple stones, while in the endoscopic group, 3 patients with stones more than 1 cm and 4 patients with multiple stones. Fourteen patients in the laparoscopic group with coexisting gallbladder stones, and 6 of their common bile duct stones were successfully removed by transcystic approach without T tube drainage. Stone removals were successful in 4 patients of the endoscopic group by a single performance, including 3 patients with single small stone and one patient with multiple small stones. Two patients in the laparoscopic group were converted to open surgery for severe adhesion and one patient in the endoscopic group turned to laparoscopic operation for failing of finding papilla in the Roux-en-Y anastomotic status. The median hospital stays were 12 d and 10 d, respectively in the laparoscopic and endoscopic group. There were 3 patients with postoperative complications, including one patient with paralytic ileus in the laparoscopic group and 2 patients with biliary pancreatitis or bacteremia in the endoscopic group, and all of them recovered uneventfully with conservative treatment.@*CONCLUSION@#Both laparoscopic and endoscopic approaches are feasible for removing stones in the common bile duct in patients with gastrojejunostomy after gastrectomy, and they complement each other. In addition, both techniques are difficult to conduct, and a technical competence should be considered in selection of each method.

Comparison of clinical effects between anterior cervical discectomy combined with corpectomy and cervical posterior single open-door laminoplasty in treating three-segment cervical spondylotic myelopathy / 中国骨伤

<p><b>OBJECTIVE</b>To compare the clinical effects between anterior cervical discectomy and fusion(ACDF) combined with anterior cervical corpectomy and fusion(ACCF) and cervical posterior single open-door laminoplasty with mini-titanium plate fixation in treating three-segment cervical spondylotic myelopathy.</p><p><b>METHODS</b>The clinical data of 63 patients (39 males and 24 females) with three-segment cervical spondylotic myelopathy underwent surgical treatment from March 2014 to March 2016 were retrospectively analyzed. Among them, 43 cases were treated by ACDF combined with ACCF(anterior group), and 20 cases were treated by cervical posterior single open-door laminoplasty with mini-titanium plate fixation(posterior group). Operative time, intraoperative blood loss, postoperative complications were compared between two groups. And according to JOA score to evaluate the clinical effect.</p><p><b>RESULTS</b>All the patients were follow-up from 16 to 40 months with an average of 25.8 months. Operative time of anterior group and posterior group were (123.70±6.21) min and(118.70±5.41) min, respectively, there was no significant difference between two groups(>0.05). Intraoperative blood loss of anterior group and posterior group were (85.23±7.51) ml and (107.18±9.41) ml, respectively, there was significant difference between two groups(<0.05). In anterior group, axial symptoms occurred in 6 cases, dysphagia in 1 case, and no C₅ nerve root palsy, hoarseness and choking cough were found, the incidence rate of complication was 16.3%(7/43); and in posterior group, axial symptoms occurred in 5 cases, C5 nerve root palsy in 1 case, and no dysphagia, hoarseness and choking cough were found, the incidence rate of complication was 30.0%(6/20); there was significant defference in incidence rate of complication between two group(<0.05). At 1 week after operation and final follow-up, the JOA scores of anterior group were obviously better than that of posterior group(<0.05).</p><p><b>CONCLUSIONS</b>Above-mintioned two surgical treatment for cervical spondylotic myelopathy can provide instantly stability, the method of ACDF combined with ACCF was obviously better that of the method of cervical posterior single open-door laminoplasty in intraoperative blood loss, the incidence rate of complications, clinical effect.Thus, for the treatment of three-segment cervical spondylotic myelopathy, the method of ACDF combined with ACCF would be firstly chosen.</p>

Imaging measurement of circumferential cortical thickness of anterior entrance and anterior half of lower cervical pedicles and its application analysis / 第二军医大学学报

Objective To measure the circumferential cortical thickness of anterior entrance and anterior half of lower cervical pedicles on computed tomography (CT) images, providing a reference for accurate anterior cervical pedicle screws. Methods CT scanning was performed in 10 normal lower cervical vertebrae from fresh cadavers, and the coronal and sagittal reconstructed images were obtained. The images were then opened in AutoCAD-2007 software to perform quantitative measurement (accuracy was 0. 1 mm) using the “dimaligned function” of dimension menu, and measurement parameters included the thicknesses of superior, medial, inferior and lateral cortex of anterior entrance of pedicle (SAE. MAE. IAE and LAE. respectively), and thicknesses of superior, medial, inferior and lateral cortex of anterior half of pedicle (SPA, MPA, IPA and LPA, respectively). Results Average thicknesses of SAE. MAE. IAE. LAE, SPA, MPA. IPA, and LPA at left and right side from Q to C7 were (1. 9 + 0. 6) and (1. 9 + 0. 5) mm, (1. 9 + 0. 7) and (1.9+0. 4) mm. (2.4 + 0. 6) and (2. 4 + 0. 5) mm, (0. 9 + 0. 5) and (0. 9 + 0. 6) mm, (2. 3 + 0. 9) and (2. 3 +0. 7) mm, (2. 1 + 0. 5) and (2. 1 + 0. 6) mm, (2. 2+0. 8) and (2. 2+0. 7) mm, and (1. 0 + 0. 7) and (1. 0 + 0. 6) mm, respectively. There was no significant difference in same measurement parameter between left and right sides at same cervical level (P>0. 05). Single factor random block analysis of variance found LAE and LPA were significantly thinner than the other 6 parameters of the same side of same cervical vertebra (all P0. 05). Conclusion LAE and LPA are the thinnest among the 8 measurement parameters from C3 to C7, which suggests LAE and LPA have the weakest resistance to exotic force if resistance strength to exotic force is parallel to cortex thickness. We should avoid locating close to LAE when finding anterior entrance or close to LPA when inserting anterior cervical pedicle screws.

Neidre and Macnab's classification Type-II B lumbosacral nerve root anomaly missed preoperatively and initially misdiagnosed as type-II A anomaly intraoperatively: A case report / 第二军医大学学报

Objective:A patient with L3-5 lumbar disc herniations and right spinal recess stenosis at L4-5 level associated with type IIB lumbosacral nerve anomaly(LSNA) at right side according to Neidre and Macnab classification system missed preoperatively and initially misdiagnosed as type IIA intraoperatively was reported. The reasons leading to missed diagnosis preoperatively and misdiagnoses intraoperatively were analyzed. Methods: A 62-year-old female was admitted to our hospital for intermittent radiating pain and claudication to the right lower extremity for about 20 years, radiating pain to the left lower extremity for 2 weeks. Physical examination found the left L5 nerve and right L4 and L5 nerves were impinged. CT and MR scannings revealed L3-4 disc herniation at right side, L4-5 disc herniation at central and left side with severe lateral recess stenosis at right L4-5 level. Image examinations failed to find a nerve root anomaly preoperatively. Following failed conservative treatment, the patient accepted decompression operation initially at left side. Left L5 nerve compressed by the herniated L4-5 disc was found firstly, which was liberated by discectomy. When doing decompression exploration at right side, it was found that two lumbar nerve roots exited L4-5 intervertebral foramen while the upper one was compressed by the herniated L3-4 disc which was liberated by discectomy and the lower one was free of compression. With exposing the right side and partly unroofing of stenosed right L4-5 lateral recess, no typical L5 nerve root was found passing over the posterior surface of the herniated L4-5 disc except that there was a slim membrane-like structure covering it. The patient was initially considered as type IIA LSNA skeptical according to Neidre and Macnad Classification. But detailed observation of the axial CT and MR sequences at L4-5 lateral recess space and sagittal CT and MR sequences at L5S1 intervertebral foramen found there was nerve-like structure, which was further confirmed to be the L5 nerve root by total unroofing of stenosed lateral recess. The membrane-like structure covering the L4-5 disc was confirmed to be the flattened right L5 nerve root compressed by herniated L4-5 disc and stenosed lateral recess, which emerged from the dura’s ventral-lateral side just above the L4-5 disc, the L5 nerve was stripped and pushed medially from its lateral boundary meticulously, L4-5 discectomy was done at right side. Intervertebral cages were inserted after L3-4 and L4-5 disc spaces preparation, following pedicle screw system fusion. Results: No nerve damage occurred intraoperatively. The patient was free of radiating pain to the left lower extremity the day after operation, two weeks later the radiating pain to the right lower extremity alleviated after temporary aggravating. Conclusion: type II lumbar nerve anomalies were not easily to be detected by CT or MR images preoperatively, that closer distance between the conjoined nerves existing the L4-5 foramen and careless observation was responsible for missed diagnosis preoperatively. That the flattened right L5 nerve covering the L4-5 disc was difficult to be recognized intraoperatively for losing its typical contour and color was responsible for misdiagnosing type-IIB anomaly as IIA LSNA.. The operators should be alert and observed carefully in case of misdiagnosing.

Prokaryotic expression, purification and identification of recombinant human atrial natriuretic peptide / 生物工程学报

In order to improve the expression of recombinant human atrial natriuretic peptide (ANP), a new plasmid (pET28a(+)/ANP₃) containing 3 tandem ANP genes with lysine codon as the interval linker, was constructed. Target gene was transformed into Escherichia coli BL21 (DE3) and induced by IPTG, about 60% of the total-cell-protein was the target protein, His₆-ANP₃. After denaturation and refolding, it was digested by Endoproteinase Lys-C and Carboxypeptidase B (CPB) and then purified by a series of purification processes, about 16 mg purified ANP monomer could be obtained from one liter bacteria broth of shaking culture. Ultimately, the purity of protein was above 90% determined by UPLC and Tricine SDS-PAGE, its molecular weight was 3 080 Da according to LC-MS identification and it was proved to be equivalent to the reference product by ELISA. The use of tandem gene expression can provide a new possible model for the expression of other peptide drugs.

Technical advances in space cell bioreactor / 医用生物力学

Cell biology experiments in space are indispensable for investigating the effects of microgravity environment on living organisms. As an important technological means of supporting life science researche, space cell bioreactor may directly influence the data quality of space cell biology experiments and research level. To date, space cell bioreactor techniques are still under development, and lack of standard rationale. In this article, the technical progresses of space cell bioreactor were reviewed, by introducing the operational principle of several typical space cell bioreactors, analyzing the mode of culture medium supplying and character of fluid mechanics environment in space, as well as the relevant supporting techniques about the parametric controlling on temperature, dissolved oxygen and pH value and on-line microscopic imaging, so as to discuss the future perspective about space cell bioreactor techniques.

Clinical observation of dynamic cervical implant (DCI) internal fixation in the surgical treatment of cervical spondylosis / 中国骨伤

<p><b>OBJECTIVE</b>To investigate the early clinical effects and radiological outcome of dynamic cervical implant (DCI) internal fixation in treating cervical spondylosis, and evaluate its safety and efficiency.</p><p><b>METHODS</b>From June 2009 to December 2011, 19 patients with cervical spondylosis correspond to the indication of DCI internal fixation in the study, including 5 cases of cervical spondylotic myelopathy and 14 cases of cervical spondylotic radiculopathy. There were 8 males and 11 females, aged from 35 to 54 years with a mean of 43.2 years. Pathological segments included C3,4 in 1 case, C4,5 in 6, C5,6 in 6, C6,7 in 4, C3,4 and C5,6, C6,7 in 2. All patients were treated with anterior discectomy and decompression and DCI internal fixation, meanwhile, 2 cases of them with anterior cervical corpectomy and fusion plate fixation. Clinical evaluation included Modified Japanese orthopedics association (mJOA), neck disability index (NDI), visual analogue scale (VAS) score and patient satisfaction index (PSI) at pre-operation and final follow-up. Radiographic evaluation included flexion/extension lateral view at operative level and adjacent segment. The adjacent level degeneration was analyzed according to Miyazaki classification on MRI images.</p><p><b>RESULTS</b>All patients were followed up from 12 to 42 months with an average of 19.8 months. Preoperative mJOA score was 13.6±1.1 and at final follow-up was 16.3±1.2 with improvement rate of 85.0%. Preoperative VAS,NDI was 6.6± 1.4, 17.1±7.4 and at final follow-up was 1.4±0.8, 6.1±3.9, respectively; there was statistical significance in all above-mentioned results between preoperative and final follow-up (P<0.05). Preoperative ROM at operation level was (7.6±1.9)° and final follow-up was (7.8+2.1)°; preoperative ROM at C2-C7 was (38.6±7.2)° and final follow-up was (39.9±6.4)°; there was no statistical significance in all above-mentioned results between preoperative and final follow-up (P>0.05). Preoperative DHI at operation level was (6.3±1.1) mm and final follow-up was (7.1±0.8) mm, there was statistical significance in DHI between preoperative and final follow-up (P<0.05). No heterotopic ossification was found. All patients followed up MRI, degeneration of 3 segments aggravated 1 degree in 38 adjacent segments, without clinical symptom.</p><p><b>CONCLUSION</b>Treatment of cervical spondylosis with dynamic cervical implant can got satisfactory outcome in early follow-up. Activity of operative segment obtain reservation in some degree. The incidence of adjacent segment degeneration is lower and no adjacent segment disease occur. Nevertheless a longer follow-up time should be needed to assess the long term functionality of the DCI and the influence on adjacent levels.</p>

[Biomechanical characteristics of hip prosthesis in hip arthroplasty treating elderly patients with Evans I-III intertrochanteric fracture of femur].

OBJECTIVE: To investigate the feasibility of hip arthroplasty in the treatment of elderly patients with Evans I-III intertrochanteric fracture of femur by analyzing its biomechanics characters. METHODS: We solved the CT digital image files with the graphics processing software Mimics at DICOM 3.0 standard, and reconstructed the three-dimensional entity of femur with CAD modeling software Unigraphics. Then the fracture line was defined in the model as the line between the tip of greater trochanter and inferior margin of small trochanter, above which the upper bone was removed. Afterwards the two prosthesises with different stem lengths (120 mm and 170 mm) were implanted into the fracture model respectively as hip arthroplasty with 3 mm bone cement layer between prosthesis and femur, and the bone defect was repatched with 5 mm bone cement layer. A three-dimensional finite element model was established with finite element analysis software ABAQUS 6.5. We formulated different material parameters under the stress condition standing with single leg to build the stress distribution map of the femur prosthesis, and took 5 loci of region of stress concentration to calculate the mean value of stress. RESULTS: The stress distribution maps of the short and long stem length prothesises were similar. And there were two areas of stress concentration, including the upper portion and the lower portion close to the joint of the prosthesis stem, and the stress concentration in the junction part was obviously between the lower portion and the upper area of the small trachanter. The stress reached the first concentration area at the junction and then gradually reached the second concentration area at the interior terminal of the stem. While the stress gradually increased along the lateral prosthesis stem, and reached the stress concentration area at the end. CONCLUSIONS: The stress distribution maps in the femur prosthesises are similar between hip arthroplasty in the treatment of intertrochanteric fracture of femur and the traditional hip arthroplasty surgery. The peak stress values are higher in the long stem prosthesis in the treatment of intertrochanteric fracture of femur than the short type, while they are under the rupture value of the metal.

Clinical application of extracorporeal membrane oxygenation for treatment of adult refractory cardiogenic shock / 中华心血管病杂志

<p><b>OBJECTIVE</b>To summarize the clinical experience of extracorporeal membrane oxygenation (ECMO) treatment for adult refractory cardiogenic shock.</p><p><b>METHODS</b>From January 2003 to January 2011, patients with refractory cardiogenic shock required veno-arterial ECMO by failure of conventional therapy and intra-aortic balloon pump counterpulsation therapy were retrospectively studied. Patients with severe traumatic brain injury, advanced malignancies and multiple organ failure were excluded. Patients were divided into weaned group (n = 31) and not weaned group (n = 23) according to the ECMO weaning.</p><p><b>RESULTS</b>The duration of ECMO was 24.16 (14.12, 56.75) hours. Twenty-two out of 31 patients in the weaned group survived and were discharged, 9 patients died after successfully weaned from ECMO (5 due to multisystem organ failure, 2 due to reoccurred cardiogenic shock, 1 due to infectious shock and 1 due to disseminated or diffuse intravascular coagulation). Pre-ECMO mean arterial pressure, ejection fraction, the duration of ECMO were significantly higher while pre-ECMO blood lactate [(8.64 ± 3.17) vs. (14.44 ± 2.52) , P < 0.01], the duration of ROSC [ (16.70 ± 5.29) vs. (35.64 ± 5.89), P < 0.01] and multisystem organ failure [0 vs. 17.4% (4/23) , P < 0.05] were lower in weaned group than in not wean group.</p><p><b>CONCLUSIONS</b>ECMO is an effective mechanical assistant therapy strategy for adult refractory cardiogenic shock patients. Timely applying this strategy on suitable patients is crucial for the success of ECMO. Cardiac function and reversibility of heart failure are key factors determine the fate of weaned or not weaned ECMO in adult refractory cardiogenic shock patients.</p>

Biomechanical characteristics of hip prosthesis in hip arthroplasty treating elderly patients with Evans I-III intertrochanteric fracture of femur / 中国医学科学院学报

<p><b>OBJECTIVE</b>To investigate the feasibility of hip arthroplasty in the treatment of elderly patients with Evans I-III intertrochanteric fracture of femur by analyzing its biomechanics characters.</p><p><b>METHODS</b>We solved the CT digital image files with the graphics processing software Mimics at DICOM 3.0 standard, and reconstructed the three-dimensional entity of femur with CAD modeling software Unigraphics. Then the fracture line was defined in the model as the line between the tip of greater trochanter and inferior margin of small trochanter, above which the upper bone was removed. Afterwards the two prosthesises with different stem lengths (120 mm and 170 mm) were implanted into the fracture model respectively as hip arthroplasty with 3 mm bone cement layer between prosthesis and femur, and the bone defect was repatched with 5 mm bone cement layer. A three-dimensional finite element model was established with finite element analysis software ABAQUS 6.5. We formulated different material parameters under the stress condition standing with single leg to build the stress distribution map of the femur prosthesis, and took 5 loci of region of stress concentration to calculate the mean value of stress.</p><p><b>RESULTS</b>The stress distribution maps of the short and long stem length prothesises were similar. And there were two areas of stress concentration, including the upper portion and the lower portion close to the joint of the prosthesis stem, and the stress concentration in the junction part was obviously between the lower portion and the upper area of the small trachanter. The stress reached the first concentration area at the junction and then gradually reached the second concentration area at the interior terminal of the stem. While the stress gradually increased along the lateral prosthesis stem, and reached the stress concentration area at the end.</p><p><b>CONCLUSIONS</b>The stress distribution maps in the femur prosthesises are similar between hip arthroplasty in the treatment of intertrochanteric fracture of femur and the traditional hip arthroplasty surgery. The peak stress values are higher in the long stem prosthesis in the treatment of intertrochanteric fracture of femur than the short type, while they are under the rupture value of the metal.</p>

Relationship between arsenic (+3 oxidation state) methyltransferase genetic polymorphisms and susceptibility to endemic arsenism / 中国地方病学杂志

Objective To investigate the association between arsenic(+3 oxidation state) methyltransferase (AS3MT) genetic polymorphism and susceptibility to endemic arsenism.Methods Polymerase chain reactionrestriction fragment length polymorphism-single strand conformation polymorphism(PCR-RFLP-SSCP) technology was performed to detect mutations of AS3MT gene intron 8 and exon 9 in genome DNA of the 79 cases and 110 controls.PCR products with abnormal band forms were further sequenced to find the types and sites of mutation.Chi-square test and multivariate Logistic analyses were conducted.Results The incidence of the 9149 base mutation(A→C) in AS3MT gene intron 8(AS3MT-9149) in case group(19.0％,15/79) was lower than that in control group (23.6％,26/110).The incidence of the codon 287 mutation(ATG→AT/CG) in AS3MT gene exon 9(AS3MT-287)in case group(10.1％,8/79) was lower than that in control group (11.8％,13/110).However,statistical analysis indicated no significant difference in both mutations between two groups[AS3MT-9149:odds ratio(OR) =0.59,95％ confidence interval(CI):0.26-1.31,P =0.195; AS3MT-287:OR =0.85,95％ CI:0.32-230,P =0.751].Conclusions There are no significant association between the genetic polymorphisms of AS3MT-9149,AS3MT-287 and the susceptibility to endemic arsenism.Similarly,due to small sample amount,we can not exclude the possibility that these gene polymorphisms are related to susceptibility to endemic arsenism.

Biomechanical supporting effect of tantalum rods for the femoral head with various sized lesions: a finite-element analysis.

BACKGROUND: Features of necrotic lesions and various interventions could affect the biomechanics of the femoral head. A three-dimensional finite-element analysis was designed to demonstrate necrotic femoral head stress changes with various sizes of necrotic lesions, and evaluate the effect of tantalum rods on preventing femoral head cracking. METHODS: Femoral computed tomography scans were used to build a normal three-dimensional finite-element femoral head model in a computer. Based on the normal model, necrotic models of different lesion diameters (15 mm, 20 mm and 30 mm) were created, as were the repaired models with tantalum rods for each diameter. After a series of meshing and force loading, the von Mises stress distributions, simulating single-legged stance, and stresses on specific points under loaded conditions were determined for each model. RESULTS: Deep exploration into the burdened area of the femoral head indicated that higher stresses to the femoral head were observed with a larger necrotic lesion; the largest stress concentration, 91.3 MPa, was found on the femoral head with a lesion diameter of 30 mm. By contrast, topical stress on the surface of the necrotic regions was lowered following implantation of a tantalum rod, and the changes in stress were significant in models with lesions of 15 mm and 30 mm in diameter, with the best biomechanical benefit from the tantalum rod found with a lesion diameter of 15 mm. CONCLUSIONS: Femoral heads with larger necrotic lesions usually have a higher stress concentration and a higher risk of collapse. Various sized lesions on the femoral head can benefit from the mechanical support offered by the implantation of a tantalum rod; however, femoral heads with smaller sized lesions may benefit more. A thorough evaluation of the lesion size should be conducted prior to the use of tantalum rod implants in the treatment of femoral head necrosis.

Therapeutic effect of an injectable sustained-release sinomenine hydrochloride and sodium hyaluronate compound in a rabbit model of osteoarthritis.

BACKGROUND: While intra-articular injection of sinomenine hydrochloride has a therapeutic effect on osteoarthritis, it has a short half-life, and is thermolabile and photolabile. The aim of this research was to evaluate the sustained-release of sinomenine hydrochloride from an injectable sinomenine hydrochloride and sodium hyaluronate compound (CSSSI) and its therapeutic effect in a rabbit model of osteoarthritis following intra-articular injection. METHODS: An injectable compound consisting of 1% sodium hyaluronate and 2.5% sinomenine hydrochloride was prepared and kept as the experiment group, and 2.5% sinomenine hydrochloride was prepared and kept as the control group. The cumulative mass release was measured at different time points in each group in vitro. Sixty-five male Zelanian rabbits were randomly divided into five groups: 15 (30 knees) each for the control, sodium hyaluronate, sinomenine hydrochloride, and CSSSI groups respectively, and five (10 knees) for the modeling group. Papain was injected into both knees of each rabbit for model establishment. Subsequently, 0.2 ml of the corresponding drugs was injected into the articular cavities of the remaining experiment groups, while the control group was treated with 0.2 ml normal saline. All groups were treated once a week for 4 weeks. Seven days after the last treatment, knees were anatomized to perform pathological observations and Mankin's evaluation of the synovium. Four groups were compared using the SPSS 13.0 software package. RESULTS: In the in vitro sustained-release experiments, 90% of the drug was released in the experiment group 360 minutes following the injection. Comparison of the Mankin's evaluations of the four groups illustrated statistical discrepancies (P < 0.05). In further paired comparisons of the CSSSI group vs. modeling control/sodium hyaluronate/sinomenine hydrochloride groups, statistical significance was uniformly obtained. Moreover, sodium hyaluronate and sinomenine hydrochloride treatments showed significant improvement over the modeling control (P < 0.05), whereas sodium hyaluronate vs. sinomenine hydrochloride comparison failed to reach significance (P > 0.05). CONCLUSIONS: CSSSI has a sustained-release effect on sinomenine hydrochloride. Intra-articular injection of CSSSI was significantly better than the sole sodium hyaluronate or sinomenine hydrochloride for the treatment of osteoarthritis in a rabbit model.

Impact of index finger force on motor unit recruitment pattern in flexor digitorum superficialis / 医用生物力学

Objective To detect the recruitment pattern of motor unit in human flexor digitorum superficialis (FDS) at different force levels produced by the index finger. Methods Eight subjects were recruited to produce a certain force level with the index finger to match the ordered force level (20%, 40%, 60% maximum voluntary contraction). During the force tracking task, the multi-channel surface electromyography (sEMG) signals were recorded on FDS using 8×1 (row×column) electrode-array. The motor unit action potential (MUAP) information was extracted by Fast Independent Component Analysis (FastICA), and then the correlation between MUAP pattern and force level was analyzed. Results Four different types of MUAP were extracted successfully by FastICA from original sEMG signals and the total number of MUAP showed an increasing trend with the force level increasing. At different force levels, the proportion of different types of MUAP was different, showing different trends with change of the force level. ConclusionsAt different levels of the finger force, the recruitment pattern of motor unit in FDS will be changed so as to produce the force accordingly.

Therapeutic effect of an injectable sustained-release sinomenine hydrochloride and sodium hyaluronate compound in a rabbit model of osteoarthritis / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>While intra-articular injection of sinomenine hydrochloride has a therapeutic effect on osteoarthritis, it has a short half-life, and is thermolabile and photolabile. The aim of this research was to evaluate the sustained-release of sinomenine hydrochloride from an injectable sinomenine hydrochloride and sodium hyaluronate compound (CSSSI) and its therapeutic effect in a rabbit model of osteoarthritis following intra-articular injection.</p><p><b>METHODS</b>An injectable compound consisting of 1% sodium hyaluronate and 2.5% sinomenine hydrochloride was prepared and kept as the experiment group, and 2.5% sinomenine hydrochloride was prepared and kept as the control group. The cumulative mass release was measured at different time points in each group in vitro. Sixty-five male Zelanian rabbits were randomly divided into five groups: 15 (30 knees) each for the control, sodium hyaluronate, sinomenine hydrochloride, and CSSSI groups respectively, and five (10 knees) for the modeling group. Papain was injected into both knees of each rabbit for model establishment. Subsequently, 0.2 ml of the corresponding drugs was injected into the articular cavities of the remaining experiment groups, while the control group was treated with 0.2 ml normal saline. All groups were treated once a week for 4 weeks. Seven days after the last treatment, knees were anatomized to perform pathological observations and Mankin's evaluation of the synovium. Four groups were compared using the SPSS 13.0 software package.</p><p><b>RESULTS</b>In the in vitro sustained-release experiments, 90% of the drug was released in the experiment group 360 minutes following the injection. Comparison of the Mankin's evaluations of the four groups illustrated statistical discrepancies (P < 0.05). In further paired comparisons of the CSSSI group vs. modeling control/sodium hyaluronate/sinomenine hydrochloride groups, statistical significance was uniformly obtained. Moreover, sodium hyaluronate and sinomenine hydrochloride treatments showed significant improvement over the modeling control (P < 0.05), whereas sodium hyaluronate vs. sinomenine hydrochloride comparison failed to reach significance (P > 0.05).</p><p><b>CONCLUSIONS</b>CSSSI has a sustained-release effect on sinomenine hydrochloride. Intra-articular injection of CSSSI was significantly better than the sole sodium hyaluronate or sinomenine hydrochloride for the treatment of osteoarthritis in a rabbit model.</p>

History of pregnancy induced hypertension is linked with increased risk of cardio-cerebral vascular events / 中华心血管病杂志

<p><b>OBJECTIVE</b>To compare the incidence of cardio-cerebral vascular events between pregnancy induced hypertension (PIH) women and non-PIH(NPIH) women.</p><p><b>METHODS</b>Ambispective cohort study method was used and 4630 pregnant women giving birth during October 1976 to December 2008 in our hospital and participated the healthy examination between July 2006 and October 2007 at Kailuan medical group were included and divided into PIH group (n = 694) and NPIH group (n = 3936) by the history of PIH. Incidence of cardio-cerebral vascular events (myocardial infarction, cerebral infarction and cerebral hemorrhage) was obtained during follow-up. Multivariable Cox proportional hazards regression models was used to assess the relative risk of cardio-cerebral vascular events.</p><p><b>RESULTS</b>(1) The follow-up time was 2 to 34 (15.32 ± 7.94) years. (2) The childbearing age, systolic blood pressure and diastolic blood pressure before delivery were significantly higher while gestational weeks and weight of newborn were significantly less in PIH group than in NPIH group (all P < 0.01). Levels of systolic blood pressure, diastolic blood pressure, waist circumference, body mass index, triglyceride, total cholesterol and fasting blood glucose during healthy examination between July 2006 and October 2007 were significantly higher in PIH group than in NPIH group (P < 0.05 or P < 0.01). (3) There were 71 cardio-cerebral vascular events during the follow-up. In PIH group, the incidence rate of cardio-cerebral vascular events, myocardial infarction and cerebral infarction was 20.64%, 11.08% and 8.67%, respectively, while the corresponding incidence rate was 7.82%, 4.02% and 2.67% in NPIH group (all P < 0.01). After adjustment for other traditional cardiovascular risk factors, the risk of total cardio-cerebral vascular events, myocardial infarction and cerebral infarction in PIH group was 2.99 fold (95%CI: 1.80 - 4.95), 3.91 fold (95%CI: 1.71 - 8.91) and 3.96 fold (95%CI: 1.95 - 8.05) higher than in NPIH group.</p><p><b>CONCLUSION</b>PIH is an independent risk factor for cardio-cerebral vascular events.</p>

Strategies for diagnosis of xanthogranulomatous cholecystitis masquerading as gallbladder cancer / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Patients with xanthogranulomatous cholecystitis sometimes exhibit imaging and intraoperative findings that are similar to those of advanced gallbladder cancer, thus these patients are easily misdiagnosed. The present study aimed to investigate the characteristics of xanthogranulomatous cholecystitis masquerading as gallbladder cancer that could potentially aid in the correct diagnosis of this condition.</p><p><b>METHODS</b>The clinical, serological, radiological and operative features of twelve patients with obviously wall-thickening or mass-forming xanthogranulomatous cholecystitis were retrospectively analyzed. Additionally, the patient preoperative features were compared to those of 36 patients with advanced gallbladder cancers.</p><p><b>RESULTS</b>Twelve patients with xanthogranulomatous cholecystitis exhibited one to three episodes of acute cholecystitis within 0.5 to 7 months prior to admission to the hospital. Five of these patients exhibited concomitant choledocholithiasis, whereas no concomitant choledocholithiasis was identified in patients with advanced gallbladder cancer. The incidence of abdominal pain (χ(2) = 6.588, P = 0.010), acute cholecystitis (χ(2) = 29.176, P = 0.000), acute cholangitis (χ(2) = 6.349, P = 0.012), choledocholithiasis (χ(2) = 16.744, P = 0.000), carcinoembryonic antigen test (P = 0.007), CA125 (P = 0.001), and diffuse gallbladder wall thickening (χ(2) = 6.031, P = 0.014), continued mucosal line (χ(2) = 15.745, P = 0.000), homogeneous enhancement of mucosal line (χ(2) = 19.947, P = 0.000), submucosal hypoattenuated nodules or band (χ(2) = 18.607, P = 0.000) in computed tomography demonstrated statistically significant differences between cases of xanthogranulomatous cholecystitis and gallbladder cancer. Furthermore, all the twelve patients with xanthogranulomatous cholecystitis exhibited at least one positive computed tomography imaging feature aside from past acute cholecystitis episode, and no patient with advanced gallbladder cancer simultaneously exhibited past acute cholecystitis episode and at least one positive computed tomography imaging feature.</p><p><b>CONCLUSIONS</b>The accurate preoperative diagnosis of xanthogranulomatous cholecystitis includes an integrated review of past acute cholecystitis episode, choledocholithiasis, and positive computed tomography imaging features. Besides, we present an algorithm for intraoperative diagnosis.</p>