ABSTRACT
Objective To quantitatively compare the γ-H2AX foci formation between DNA-PKcs+/+and DNA-PKcs-/-mouse embryonic fibroblast(MEF)cells,and to investigate the dynamic changes in DNA double-strand breaks(DSBs)in human nasopharyngeal carcinoma SUNE-1 cells exposed to X-ray radiation. Methods The expression of DNA-PKcs was determined by Western blot. The γ-H2AX foci formation induced by 5 Gy X-ray radiation was detected by cell immunofluorescence. The ImageJ software was used to quantitatively analyze the γ-H2AX foci formation. Results The expression of DNA-PKcs was silenced in DNA-PKcs-/-MEF cells and normal in DNA-PKcs+/+MEF cells. According to the dynamic analyses of the numbers of γ-H2AX foci/cell and γ-H2AX foci/mm2, a similar tendency was observed in DSB formation in DNA-PKcs+/+MEF cells, DNA-PKcs-/-MEF cells,and SUNE-1 cells exposed to X-ray radiation. A large number of γ-H2AX foci formed at 0.5-1.0 h after radiation. DSBs were repaired at 6 h after radiation in DNA-PKcs+/+MEF cells and 24 h after radiation in DNA-PKcs-/-MEF cells and SUNE-1 cells. The peak values of γ-H2AX foci/cell and γ-H2AX foci/mm2were observed at 1.0 and 0.5 h after radiation, respectively. Compared with DNA-PKcs+/+MEF cells, DNA-PKcs-/-MEF cells had different numbers of γ-H2AX foci/cell at 0.5, 1.0, 3.0, 6.0, and 12.0 h after radiation, as well as different numbers of γ-H2AX foci/mm2at 3.0, 6.0, and 12.0 h after radiation. Conclusions Quantitative measurement of the number of γ-H2AX foci/cell or γ-H2AX foci/mm2by cell immunofluorescence provides new insights into the quantitative and dynamic study of DSB damage and repair.
ABSTRACT
Objective To compare the effectiveness and mechanical differences in the dynamic hip screw (DHS), proximal femoral nail antirotation (PFNA), and proximal femoral internal fixator (PFI) for fixing complex unstable proximal intertrochanteric fractures by biomechanical testing. Methods Eighteen Synbones of the proximal femur were made to simulate complex unstable femoral intertrochanteric fracture models (Evans-Jensen TypeⅢ), which were fixed by DHS, PFNA, and PFI, respectively. The models were tested using a biomechanical testing machine, in order to compare their differences and advantages for fixing fractures. Results Under the compressive loads of 300, 600, and 1 200 N, the fracture displacement of the DHS was the maximum, with a significant difference compared with PFNA and PFI (P0.05). Under torsional loads of 300, 600, and 1 200 N, the torsional displacements of DHS and PFNA at the fracture ends were the maximum, with no significant difference (P>0.05). There were significant differences between PFI and PFNA as well as PFI and DHS (P<0.05). Conclusions For complex unstable proximal intertrochanteric fractures, the stability of the compression resistance of the PFI system is similar to that of the PFNA system. However, the torsional resistance of PFI is stronger than that of PFNA. The DHS system shows the least resistance with respect to compression and torsion.
ABSTRACT
Objective To study the micro-pore architecture and mechanical properties of porous titanium scaffolds with diamond molecule structure produced by 3D print technology,so as to guide the development of 3D-prinited porous titanium orthopedic implants.Methods Selective laser melting (SLM) and electron beam melting (EBM) were used to fabricate porous Ti6Al4V scaffolds with diamond molecule structure.The micro-pore architectures of those scaffolds were observed using optical microscope and scanning electron microscope (SEM),and universal material testing machine was used to conduct compressive test on the scaffolds.Results Both SLM and EBM techniques had machining error and half-melted metal particles were found on the strut surface.The relative error of strut size produced by SLM and EMB was 20.9％-35.8％ and-9.1％-46.8％,respectively.The scaffold with strut width of 0.2 mm could not be produced by EBM.The compressive strength and elastic modulus of the scaffold fabricated by SLM was 99.7-192.6 MPa and 2.43-4.23 GPa,respectively.The compressive strength and elastic modulus of the scaffold fabricated by SLM was 39.5-96.9 MPa and 1.44-2.83 GPa,respectively.Conclusions The manufacturing precision of SLM is higher than that of EBM.Porosity is the main factor that affects the compressive strength and elastic modulus of the scaffolds.In the same process,with the increase of porosity,both the compressive strength and elastic modulus decrease.When the porosities are similar,the scaffolds fabricated by SLM possess higher compressive strength and elastic modulus than those by SLM.
ABSTRACT
Objective To evaluate the feasibility of the porous titanium/chitosan/hydroxyapatite (Ti/Ch/HA) composite scaffold as a bone repair substitute.Methods Additive manufacturing (3D printing) technology was used to fabricate porous Ti scaffolds as supporting structures.Chitosan/hydroxyapatite (Ch/HA) sponge was prepared within the macro-pores of Ti scaffolds using freeze drying technology.Thus,a kind of composite porous Ti/Ch/HA scaffold with good cell affinity was obtained.Osteoblastic cells were seeded and cultured in pure porous Ti scaffolds and composite Ti/Ch/HA scaffolds for 7 days.The cellular morphology,seeding efficiency and proliferation were examined and compared between the 2 kinds of scaffolds using scanning electron microscopy (SEM) and MTT assay.Results The SEM examination showed that the macro-pores of Ti/Ch/HA scaffolds were full of the composite sponge structure of Ch/HA,with a micropore size of 50 to 200 μm.Like the pure porous Ti scaffolds,composite Ti/Ch/HA ones have a compressive strength of 168.2 to 192.6 MPa,a yielding strength of 137.1 to 154.1 MPa,and a Young's modulus of 3.21 to 4.51 GPa.After culture for 7 days,a large number of flat cells adhered onto the surface of Ti scaffolds while the cells adhering onto the Ti/Ch/HA composite scaffolds were fusiform.The seeding efficiency of osteoblastic cells in the composite Ti/Ch/HA scaffolds (73.218％ ± 3.748％) was significantly higher than that in the pure porous Ti scaffolds (21.352％ ±4.365％) (P ＜0.05);the OD value of the composite Ti/Ch/HA scaffolds (0.783 ±0.043) was significantly higher than that of the pure porous Ti scaffolds (0.382 ± 0.036) (P ＜ 0.05).Conclusions Ti/Ch/HA composite scaffolds can match human bone in mechanical properties.Compared with pure porous Ti scaffolds,the Ti/Ch/HA composite ones are more suitable for adhesion and proliferation of osteoblasts,making them an ideal kind of bone repair substitute.
ABSTRACT
Objective At present,nasopharyngeal carcinoma (NPC) is a head and neck cancer with special geographical distribution and biological behavior.Studies have shown that 18 F-FDG PET/CT parameters have certain prognostic values in patients with NPC in high-incidence areas.The aim of this study is to investigate the prognostic values of 18 F-FDG PET/CT parameters in patients with NPC in low-incidence areas.Methods The clinical data of 83 NPC patients who were diagnosed and treated in Beth Israel Medical Center, Albert Einstein Medical College from January 2003 to December 2013 were analyzed retrospectively.Based on 18 F-FDG PET/CT images,gross tumor volume (GTV) was delineated using the gradient method to obtain 18 F-FDG PET/CT parameters:maximum standardized uptake value (SUVmax ), metabolic tumor volume ( MTV),and total lesion glycolysis ( TLG).Results The number of patients followed was 37 at 3-years time.For all patients,the 3-year failure-free survival,locoregional relapse-free survival,and metastasis-free survival rates were 74%,88%,and 85%,respectively.The univariate analysis showed that SUVmax of the primary tumor (P=0.004) and TLG (P=0.014) were prognostic factors for 3-year locoregional relapse-free survival rate,and SUVmax of the primary tumor (P=0.024) and TLG (P=0.033) were prognostic factors for 3-year failure-free survival rate.The multivariate analysis showed that SUVmax of the primary tumor was the independent prognostic factor for 3-year failure-free survival rate. Conclusion SUVmax of the primary tumor before treatment is the independent prognostic factor for failure-free survival in patients with NPC.
ABSTRACT
Objective To analyze the clinical factors for pathologic complete response ( pCR) after preoperative neoadjuvant chemoradiotherapy ( neo?CRT) for locally advanced rectal cancer. Methods From 2005 to 2012, 297 patients with locally advanced rectal cancer and complete clinical data were enrolled as subjects. Those patients were diagnosed with biopsy and treated with neo?CRT ( radiotherapy by 3?dimonsional conformal radiotherapy or volumetric?modulated arc therapy) followed by radical surgery. The logistic regression model was used for the multivariate analyses of the correlation of pCR with age, gender, distance between tumor and the anal verge, serum level of carcinoembryonic antigen ( CEA ) before treatment, hemoglobin level before treatment, cT staging, and cN staging. Results In all patients, 78 ( 26?7%) patients had pCR after treatment. The numbers of patients with pCR were 42( 34?4%) in patients with stage T1?T3 disease and 37(21?1%) in patients with stage T4 disease. In the patients with serum CEA levels no higher than 5?33 ng/ml, 55(36?4%) had pCR after treatment, while in the patients with serum CEA levels higher than 5?33 ng/ml, only 24( 16?4%) had pCR. The univariate analysis revealed that age, gender, distance between tumor and the anal verge, anemia before treatment, or cN staging were not related to pCR. The multivariate analysis showed that stage cT1?T3 and a serum CEA level no higher than 5?33 ng/ml before treatment were influencing factors for pCR after neo?CRT for locally advanced rectal cancer ( P=0?031,P=0?000) . Conclusions The clinical staging and the serum CEA level before treatment are influencing factors for pCR after neo?CRT for locally advanced rectal cancer. The serum CEA level before treatment can be considered as a predictor of pCR after neo?CRT for locally advanced rectal cancer.
ABSTRACT
Objective To explore the predictive value of primary tumor site for loco?regional recurrence ( LRR) in early breast cancer patients with one to three positive axillary lymph nodes after radical surgery. Methods The clinical data of 656 patients pathologically diagnosed with pT1?2 N1 M0 breast cancer who received radical surgery without postoperative radiotherapy in our hospital from 1998 to 2010 were retrospectively analyzed. In those patients, 156 had primary tumor located in the inner quadrant, 45 in the central quadrant, and 455 in the outer quadrant. LRR and local recurrence?free survival ( LRFS) were end points. The Kaplan?Meier method was used to estimate LRR and LRFS rates. The log?rank test was used for survival difference analysis and univariate prognostic analysis. Multivariate analysis was performed using the Cox regression model. Results The 5?and 10?year sample sizes were 416 and 191, respectively. The 5?and 10?year LRR rates were 8?6% and 12?9%, respectively, while the 5?and 10?year LRFS rates were 86?2%and 76?4%, respectively. The univariate analysis indicated that age, pT stage, Ki67 level, molecular classification, and primary tumor in the inner quadrant were significant influencing factors for LRR ( P=0?000,0?006,0?017,0?004,0?000). The multivariate analysis showed that age no greater than 35 years, primary tumor in the inner quadrant, and non?luminal subtype in molecular classification were independent prognostic factors for LRR and LRFS ( P=0?0012,0?012,0?005) . With an increasing number of risk factors ( ≥ 2 ) , patients with primary tumor in the inner quadrant had a dramatically increased LRR rate and a reduced LRFS rate, while patients with primary tumor in the outer or central quadrant kept the same LRR and LRFS rates. Conclusions The primary tumor site holds promise for prediction of LRR and LRFS in patients with pT1?2N1M0 breast cancer after radical surgery. Patients with primary tumor located in the inner quadrant have a high LRR rate and a low LRFS rate, which provides an excellent predictor for the risk of recurrence in patients with high?risk breast cancer.
ABSTRACT
This paper presents a unit free-form deformation (FFD) method applied to rapid three-dimensioanl (3D) bone reconstruction, which was based on traditional FFD. With the femur as an example, we reconstructed a 3D model of femur from two X-ray images and a standardized model by taking advantage of unit FFD algorithm. The X-ray images and its parameters were taken by C-arm device. Those parameters and X-ray contour are contributed to 3D reconstruction. The out contours of X-ray image and standard model were connected by point matching algorithm. The unit-FFD lattice was built to reconstruct standard model and finally made the contour of X-ray image and standard model exactly the same. Experiments on shape accuracy, robustness and time consuming, carried out by 35 specimen from cadaver, showed that mean error of shape (0. 52 mm) and mean construction time (112 s) were lower than those using traditional method (0.7-2.6 mm, 8-20 min). The method proposed in this paper shows a good prospect in clinical application and related research.
Subject(s)
Humans , Algorithms , Femur , Diagnostic Imaging , Imaging, Three-Dimensional , Models, Anatomic , RadiographyABSTRACT
Objective To validate the safety and accuracy of a rapid prototyping drill template (RPDT) for posterior atlantoaxial transarticular screw placement and analyze factors for screw deviation.Methods Twelve normal cadaveric cervical spines were examined using 64 slice CT with 1-mm thick scan and data in Dicom format were recorded.After data was processed using software Mimics 10.01 for three-dimensional (3-D) model reconstruction,computer-assisted design of optimum trajactory for atlantoaxial transarticular screw placement was worked out and made into a drill template,where the surface was created as the inverse of axial posterior surface.The drill template was materialized in a rapid prototyping machine and used to place the screws.After surgery,the position of posterior atlantoaxial transarticular screw was evaluated by X-ray and CT scan.Screw entry point,angle and orientation of the optimal and actual trajactory were determined after fitting the position of the pre-operative and post-operative specimen in computer software and the redefining the 3-D coordinate axis.Results Twenty-four screws were implanted with no cortex perforation.Depth of the optimum save screw trajectory for atlantoaxial transarticular fixation was (37.34 ± 2.31) mm on the left side and (37.11 ± 2.21) mm on the right side.Introversion angles of the optimum save screw trajectory was 0° in both sides,but the actual angle was (0.15 ±0.58)°on the left side and (0.11 ±0.46)°on the right side.Elevation angle of the optimum save screw trajectory was (49.35 ± 1.62) °on the left side and (48.83 ± 1.83) ° on the right side,but the actual angle was (49.29 ± 1.68) °and (49.10 ± 1.45) °respectively.Average displacement of screw entry point in the x,y and z axis was respective (0.21 ±0.65) mm,(0.69 ± 1.48) mm and (0.39 ±0.11) mm on the right side,while (0.19 ± 0.66) mm,(0.53 ± 1.45) mm and (0.38 ± 0.13) mm on the left side.There were no statistically significant differences in deviation levels of entry point and orientation between the optimum and actual screw trajectory (P ＞ 0.05).Conclusions Causes for deviation in RPDT-assisted placement of atlantoaxial transarticular screw are mainly intrinsic factors of the hardware and software and human factors in the operation.RPDT is easy in operation and has individualized design,which greatly improves the accuracy of screw placement and reduces screw deviation.RPDT can be widely used in clinical practice.
ABSTRACT
The FE model of proximal humeral locking plate was established and analyzed to provide academic support of the proximal humeral locking plate failure. The stress distributions of the locking plate were observed under the situations of the fracture area providing support and without support. In summary, this type of locking plate cannot afford the stress at 120 degrees abduction position under the situation of fracture area provides without support. In order to reduce the probability of locking plate failure, it is recommended that using other type of locking plate instead or avoiding 120 degree abduction of the patient.
Subject(s)
Humans , Bone Plates , Equipment Failure Analysis , Finite Element Analysis , Humeral Fractures , Materials Testing , Prosthesis Failure , Stress, MechanicalABSTRACT
A whole technical way of reconstructing 3D model of the scoliotic spine from two X-ray images was proposed. From the experimental results of 30 patients with mild to severe scoliosis, we can conclude that the accuracy of locating vertebrae is 0.5 mm, the orientation accuracy was 1.5. After comparing the results with those using the previous methods, we found that the method proposed in this paper can get higher resolution with less computational time, making it suitable for clinical routine use.
Subject(s)
Humans , Imaging, Three-Dimensional , Methods , Models, Statistical , Radiography , Scoliosis , Diagnostic Imaging , Spine , Diagnostic ImagingABSTRACT
This paper is aimed to focus on the joint prosthesis failure event, to collect the statistic data about the failure of artificial joints issued by authoritative organizations at home and aboard, and to compare the functions of different types of the artificial joints. We generalized and compared current study analyzing the failure reason and type of joint prosthesis, and categorized the failure events according to the failure occurring time, i. e. short-term, medium-term and long-term. This paper could be helpful for improving and summarizing of artificial joint replacement surgery, and could put forward the requirements for the future artificial joints.
Subject(s)
Humans , Arthroplasty, Replacement , Arthroplasty, Replacement, Hip , Arthroplasty, Replacement, Knee , Joint Prosthesis , Prosthesis FailureABSTRACT
The orthopedics implants failure management system has been put forward according to the present status. The function of the system and typical failure case reasoning route also have been described. Furthermore, the analysis process has been presented by illustrating a typical failure case analysis.
Subject(s)
Medical Records Systems, Computerized , Orthopedic Procedures , Prosthesis Design , Prosthesis Failure , Software DesignABSTRACT
This paper focused on the joint prosthesis failure event, through survey and investigation in different kinds of case studies, generalized and analyzed the failure reason of joint prosthesis. The failure reason been categorized according to the failure occurring time: short-term, medium-term and long-term, and for each category, the characteristics and root causes are discussed, and the corresponding countermeasures put forward.
Subject(s)
Humans , Arthroplasty, Replacement , Equipment Failure Analysis , Joint Prosthesis , Prosthesis FailureABSTRACT
Objective To explore the outcomes of computer-assisted design of therapeutic personalized footwear for diabetic foot.Methods Fifty-eight cases of diabetic foot were included in the study.Ten items of data from theses patients were measured with methods provided by Salford University.All characteristics of the footwear were calculated with computer.Shoes were specially designed with the formula and computational method provided by Safford university.All patients had worn the shoes for 13 months.Special questionnaires were used to measure the outcomes.Results Thirty-two cases had been followed up for one month,25 cases for 2 months,25 cases for 3 months and 42 cases for 13 months.The score had improved from 67.94±15.14 before wearing the shoes to 78.13±1.44 thirteen months after wearing.The health score of the foot had improved.There was significant difference between before and after wearing the footwears.Conclusion Special-designed diabetic shoes play an important role in the prevention of ulcer for diabetic foot patients.Computational method and data model obtained from Salford university needs to be modified when applying it for Chinese.
ABSTRACT
In order to maintain good communication between the optical tracking system and image-based surgical navigation software through the serial port, we developed a serial communication software by calling the WinAPI function with Visual C++ 6.0. We then completed the data reading, integration and analysis. We further calculated the relative position between the surgical instruments and the patient coordinate system, realized the registration between the CT model data and the spatial location of patient by using ICP algorithm, and finally achieved real-time tracking surgical instruments on the surgery. The practical effects of clinical surgery have proved that this system has good robustness, real-time property and reliability, which can meet the requirements of clinical surgery.
Subject(s)
Humans , Algorithms , Electronic Data Processing , Computer Simulation , Image Processing, Computer-Assisted , Imaging, Three-Dimensional , Software , Surgery, Computer-Assisted , Methods , Tomography, X-Ray Computed , User-Computer InterfaceABSTRACT
Objective To apply the three-dimensional pre-operative simulation and intra-operative real-time navigation in the reconstruction of old maxillofacial fractures so as to increase the surgical precision. Methods Six patients with old maxillofacial fractures were enrolled, and the diagnosis of unilateral old maxillofacial fractures was confirmed by clinical and imaging examinations. Virtual three-dimensional skull models were reconstructed from pre-operative CT images. The fractured bone was moved or rotated, and was reposed in a desired site according to the mirrored part from the healthy side. After patient-to-image registration, the surgical instruments and patients were tracked in real-time by optical tracking system during operation, and in this way the maxillofacial fractures were reposed satisfactorily guided by the virtual image. Results Three-dimensional simulation before operation and real-time navigation of patients and instruments during operation were realized. The error of registration was less than 1 mm. The post-operative CT examinations of these six patients revealed that the fracture reposition was same to the pre-operative planning, and the difference between them was less than 1.5 mm. The operations were minimally-invasive, with no complications. Conclusion Computer-aided surgical simulation and navigation system can effectively increase the surgical precision of reconstruction of old maxillofacial fractures.
ABSTRACT
Objective In order to avoid potential injuries imposed to human body,it could be feasible to use the musculoskeletal models which can be reconstructed from the cadaver color cryosection(CCC)images,computerized tomography(CT)images,magnetic resonance(MR)images or other images to analyze the dynamic properties of muscles in vivo during human movement.Mothod We reconstruct the lower limb musculoskeletal model and define the uniform ioint coordinate system(JCS)on the model and the subject.The coordinate transformation of the muscle attachment points both on the model and the subject is described in detail.Results The length and the moment arm of the biceps femoris(short head)during knee flexion are calculated and analyzed.Conclusion This method plays an important role in improving the kinematics and dynamic simulation and the muscle force estimation.
ABSTRACT
A novel fibrinolytic enzyme subtilisin FS33, which exhibits much higher activity for decomposing fibrin than urokinase, was purified from Douchi, a traditional soybean-fermented food in China. In order to increase bio-utilization and thrombus targetability of subtilisin FS33 labeled by fluorescein isothiocyanate (FITC), the surface modified liposomes encapsulating subtilisin FS33 and FITC with a synthetic peptide Arg-Gly-Asp-Ser (RGDS), being putatively a specific antagonist of fibrinogen receptor on platelet membrane, were prepared and used to evaluate the therapeutic efficacy in a rat model thrombotic carotid artery. The arterial thrombosis was induced by applying two pieces of filter paper (1 x 2 cm) saturated with 10% of ferric chloride (FeCl3). The rats were infused via the jugular vein with either liposomes carrying BSA (control group) or RGDS-liposomes carrying subtilisin FS33 at doses of 2000 and 4000 U/kg. The plasma of the group infused with RGDS-liposomes showed higher antithrombotic and fibrinolytic activity than did the control group within 15-120 min after infusing. The higher the dose was gived, the higher the activity was shown. APTT(activiated partial thromboplastin time), PT (prothrombin time) and TT (thrombin time) were extended remarkably (P < 0.05, P < 0.01), and FDP (fibrinogen degradation products) also increased greatly (P < 0.01), while ELT (euglobulinlysis time) decreased obviously (P < 0.05). FITC content in heart and brain evidently increased (P < 0.05), and results of D-dimer test were all positive. In addition, the venous thrombi in brain and kidney were dissolved totally or partly as observed by patholgical section. All these indicated that subtilisin FS33 enhanced the antithrombotic and fibrinolytic activities in rat, and RGDS-liposomes improved, in a certain degree, the thrombolytic specificity for targeting to thrombus.
Subject(s)
Animals , Female , Male , Rats , Carotid Artery Thrombosis , Drug Therapy , Drug Carriers , Drug Delivery Systems , Fibrinolytic Agents , Liposomes , Chemistry , Oligopeptides , Chemistry , Random Allocation , Rats, Wistar , SubtilisinsABSTRACT
Artificial knee joint simulation test is an important form in the research and evaluation of prosthetic material and design. Natural knee joint could not be tested by conventional instruments because of complex motion and load in movement. Simulation test designed for artificial knee is needed. At present, two kinds of simulation, namely simplification method and complete simulation, are widely used. Complete simulation can be used for simultaneous evaluation of material and design of prosthesis, whereas simplification method is only useful in evaluating the material of prosthesis. In international standards, there are already two protocols for artificial knee joint experiment, namely load control and displacement control. This paper also reviews the evaluation criteria and measurement standards for artificial knee joint simulation test, and then envisages the researches in future.