3D finite analysis on injury mechanism of spinal cord compression / 医用生物力学

Objective To construct 3D finite element model of the thoracolumbar spinal cord, and study the mechanism of spinal cord injury caused by burst fracture through biomechanical experiments. Methods The compression simulation on burst fracture was performed using finite element technology, and the results were verified by comparing the tested models with the in vivo and in vitro experimental results. Results The strain distribution in white matter of the spinal cord was higher than that in grey matter at the initial stage of burst fracture. As the displacement of bony fragments increased, the strain distribution in grey matter increased subsequently. But when the displacement of bony fragments finally reached the maximum, the strain in white matter was higher than that in grey matter. Conclusions Traumatic severity of the spinal cord during burst fracture is dependent on the posterior encroachment, and the traumatic procedure order for ventral horn (motor function) or dorsal horn (sensory function) of cord tissue also plays an important role in the evaluation. In clinical practice, the patient’s condition can be evaluated more accurately by assessing severity of the spinal motor and sensory functions. Further understanding on strain distribution in the spinal cord during the injury may inspire new strategies for treating or preventing spinal cord injury.

Establishment of a goat model of tibial bone hole defect suitable for repair using injectable bone materials / 南方医科大学学报

<p><b>OBJECTIVE</b>To prepare a goat model of tibial bone hole defect suitable for studies of bone defect repair using tissue-engineered injectable bone materials.</p><p><b>METHODS</b>A circular hole bone defect 1.2 cm in diameter was induced below the tibial medial plateau of the goat. X-ray, histological inspection, and image analysis were carried out to evaluate the validity of the model in simulating limb bone defect for the study of tissue-engineered injectable bone materials.</p><p><b>RESULTS</b>At 4 and 8 weeks after the operation, neither X-ray nor histological examination showed obvious bone tissues in the bone defect. Image analysis showed a area of new bone tissue formation of (8.79 - or + 3.63)% in the total defect area at 4 weeks, which increased to (15.41 - or + 4.21)% at 8 weeks.</p><p><b>CONCLUSION</b>The goat model of tibial bone hole defect established in this study is suitable for studying the ability of injectable bone materials for repairing limb bone defect, and offers a simple and reliable means to simulate the local condition of bone regeneration and mechanical environment of bone defect in the limbs.</p>

Effects of cyclosporine-impregnated versus freeze-dried bone allografts in repairing radial defects in rabbits: a comparative study / 南方医科大学学报

<p><b>OBJECTIVE</b>To compare the effects of cyclosporine-impregnated bone allograft (CAB) and freeze-dried bone allograft (FDAB) in repairing radial defects in rabbits.</p><p><b>METHODS</b>Thirty New Zealand white rabbits were randomized into bone graft donor group, experimental group, and control group (n=10). The bilateral ilia of the donor rabbits were dissected to prepare CAB and FDAB. In the other 20 rabbits, a 10-mm long segmental osteoperiosteal defect was induced in the right radius and repaired with CAB (experimental group) or with FDAB (control group). At postoperative weeks 4 and 12, 5 rabbits from each group were sacrificed to evaluate the bone healing by radiographic, general and histological observations.</p><p><b>RESULTS</b>Four weeks after the operation, the rabbits in the experimental group showed significantly higher X-ray scores (P=0.001) with greater amount of new bone and better incorporation of the allograft and autogenous bone than those in the control group. At 12 weeks, the X-ray scores were still significantly higher in the experimental group (P=0.002), which also showed better bone remodeling than the control group.</p><p><b>CONCLUSION</b>CAB is superior to FDAB for repairing radial defects in rabbits, but the potential involvement of local immunoreaction in this difference awaits further investigation.</p>

Three-dimensional visualization of virtual surgery for intertrochanteric fractures / 南方医科大学学报

<p><b>OBJECTIVE</b>To establish a computer-aided three-dimensional visualization operation simulation system based on Mimics and Unigraphics NX software to provide reliable evidence for accurate preoperative surgical planning.</p><p><b>METHODS</b>The preoperative CT scans of 5 patients with intertrochanteric fractures were used for three-dimensional reconstruction of intertrochanteric fractures using Mimics software. Three-dimensional reconstruction of the surgical instruments was carried out using the modeling function of Unigraphics NX software, whose assembly function was used to visualize the simulates internal fixations of intertrochanteric fractures with dynamic hip screw (DHS) system. The operative procedures simulated by Unigraphics NX were analyzed preoperatively.</p><p><b>RESULTS</b>The virtual surgery procedures were clearly and vividly visualized in three dimensions. The fracture reduction and surgical effects could be predicted using this system.</p><p><b>CONCLUSIONS</b>This system of three-dimensional visualization of virtual surgery for intertrochanteric fractures has important values in surgical planning, risk assessment and clinical training, and can help improve the reliability and outcome of orthopedic surgery.</p>

Isolation, culture and chondrogenic differentiation of goat bone marrow mesenchymal stem cells / 南方医科大学学报

<p><b>OBJECTIVE</b>To explore the isolation, in vitro culture and chondrogenic differentiation of goat bone marrow mesenchymal stem cells (BMSCs).</p><p><b>METHODS</b>Bone marrow was harvested from a 10-month-old Chinese goat for adherent culture of the BMSCs in vitro. Flow cytometry was performed to detect the cell surface markers of the BMSCs of the fourth generation. The induction medium (containing 10% fetal bovine serum, high-glucose DMEM, 6.25 microg/ml insulin, 6.25 microg/ml transferrin, 50 microg/ml vitamin C, 100 nmol/L DXM and 10 ng/ml transforming growth factor-beta1) was then applied for chondrogenic differentiation. Cytochemical staining, RT-PCR and Western blotting were performed to detect the expressions of type II collagen and aggrecan in the cells at the time points of 0, 1, 2 and 4 weeks.</p><p><b>RESULTS</b>The goat BMSCs grow well in vitro with a high purity in the fourth generation. The expression of chondrocyte phenotypes were observed at 1, 2 and 4 weeks, which became more obvious as the culture prolonged. The mRNA and protein expression of type II collagen and aggrecan in the BMSCs increased obvious after the induction and had reached a satisfactory level by 2 weeks.</p><p><b>CONCLUSION</b>Goat BMSCs have the potential to differentiate into chondrocytes in vitro, and the results of this study provide the experimental basis for application of goat BMSCs in bone and cartilage tissue engineering in vivo.</p>

Three-dimensional reconstruction technique in gastrocnemius flap surgery: initial clinical application / 南方医科大学学报

<p><b>OBJECTIVE</b>To discuss the experience with three-dimensional reconstruction technique in initial clinical application in gastrocnemius muscle flap surgery.</p><p><b>METHOD</b>From 2007 to 2008, 7 patients received gastrocnemius muscle flap surgeries to repair the wounds. Preoperative CT angiography or magnetic resonance imaging (MRI) was performed after injection of the contrast media for individualized three-dimensional gastrocnemius muscle flap reconstruction using Amira4.1 software. According to the size of the defect in the wound, individualized three-dimensional gastrocnemius muscle flap was designed and harvested from the posterior leg.</p><p><b>RESULTS</b>Individualized three-dimensional reconstruction of the gastrocnemius flap was performed in 7 cases, and the reconstructed flaps clearly displayed the blood vessels, skin and the adjacent three-dimensional structures. In 6 cases the main perforating branched and trunk of the blood vessels in the designed flap were consistent with the surgical findings; in 1 case, the perforating branches failed to be clearly displayed in the designed flap, and surgical examination identified perforating branches with an average diameter of 0.5 mm (minimally 0.3 mm). The flaps survived in all the 7 cases.</p><p><b>CONCLUSIONS</b>Three-dimensional reconstruction of the gastrocnemius flap based on the lower limb CT angiography or MRI allows three-dimensional observation of the anatomy of the flap and accurate marking of the extent of the flap to be harvested, therefore avoiding intraoperative injuries to the blood vessels to better survival of the flaps.</p>

Design and preliminary clinical application of a new digitalized navigation template for fixation of the inferior tibiofibular joint / 南方医科大学学报

<p><b>OBJECTIVE</b>To design and prepare a new digitalized navigation template for fixation of inferior tibiofibular joint using three-dimensional reconstruction and reverse engineering techniques.</p><p><b>METHODS</b>Five patients with inferior tibiofibular joint rupture without fibula fracture underwent three-dimensional CT scanning of the lower limbs. The image data were transferred into Mimics software, and after reconstruction of the three-dimensional models of inferior tibiofibular joint rupture and saving in .stl format, the three-dimensional models were imported into Imageware10.0 software to determine the three-dimensional plane of reference. The location of the optimal pedicle channel was defined using reverse engineering and AO internal fixation principle. The template was designed according to the anatomic features of the fibular surface, and the optimal pedicle channel and the template were overlapped as the navigational template, which was manufactured by rapid prototyping. The inferior tibiofibular joint was reduced and the template was placed distally on the external fibula, and the location for screw insertion was defined by the navigation template.</p><p><b>RESULTS AND CONCLUSION</b>The digitalized model of the inferior tibiofibular joint was established. The navigation template manufactured offered good compatibility and was applied successfully for fixation of the inferior tibiofibular joint. This approach provides a new means for fixation of ruptured inferior tibiofibular joint using the reverse engineering and digitized 3-dimensional reconstruction techniques.</p>

Establishment of a digital Evans-Jensen classification model of femoral intertrochanteric fracture / 南方医科大学学报

<p><b>OBJECTIVE</b>To establish a digitized Evans-Jensen classification model of femoral intertrochanteric fracture.</p><p><b>METHODS</b>The hip of a healthy male volunteer was examined with 64-slice spiral CT, and the data were processed using Mimics 10.01 software to reconstruct the proximal femur model. According to Evans-Jensen classification criteria of femoral intertrochanteric fracture, each type of fracture model was simulated. Five orthopedic surgeons and 10 medical students undertook the preliminary evaluation of the digital fracture model.</p><p><b>RESULTS</b>The digital fracture model is intuitive, three-dimensional, and realistic with good visual effect. The fracture could be observed and charted from optional direction and angle. The corresponding animation allowed 360 degrees rotation. Evaluation by the 4 orthopedic surgeons and 10 medical students confirmed that the digital fracture model was intuitive and easy to understand.</p><p><b>CONCLUSION</b>The digital model of femoral intertrochanteric fracture is intuitive, three-dimensional, realistic and dynamic, and may help in clinical practice and medical teaching.</p>

Preliminary separation of the growth factors in platelet-rich plasma: effects on the proliferation of human marrow-derived mesenchymal stem cells / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Platelet-rich plasma (PRP) as a storage vehicle of growth factors has been successfully used in clinical applications, but in most cases the platelets were autologous. However, the large volume of blood withdrawn has detrimental effects on patients with anemia or poor general health. To overcome these limitations, this study was designed to separate the growth factors in homologous platelet-rich plasma.</p><p><b>METHODS</b>The gel chromatography with Superdex-75 column was applied to separate PRP supernatants into 4 major fractions. Then the four fractions were vacuumed freeze-dried and re-dissolved in phosphate buffered saline. Proteins concentrations in PRP and in four fractions were detected by bicinchoninic acid protein assay; platelet derived growth factor-AB (PDGF-AB) and transforming growth factor beta1 (TGF-beta1) levels were determined by sandwich enzyme-linked immunosorbent assays. The effects of fractions on the proliferation of human marrow-derived mesenchymal stem cells (MSCs) were determined by 3-(4, 5- dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) assay.</p><p><b>RESULTS</b>PRP supernatants were separated into four major fractions by gel chromatography. The proteins recovery was 96.72%. Of the four fractions, fraction B contained the highest TGF-beta1 and PDGF-AB levels, and the highest proteins concentrations. Cell proliferation curves of MSC demonstrated that fraction B and C induced a remarkable increase of MTT values compared to the untreated culture (P < 0.05), and the effects of fraction B and C showed no significant difference compared to the PRP group (P > 0.05). Fraction A and D showed no significant difference to the negative control group (P > 0.05).</p><p><b>CONCLUSIONS</b>The growth factors in PRP supernatants could be preliminarily separated into four fractions by gel chromatography, and the freeze-drying fractions retained the biological activity of growth factors. The growth factors were mostly presented in fraction B and C, and they promoted cell proliferation effectively.</p>

Effect of vascular endothelial growth factor gene transfer on proliferation and metabolism of human bone marrow stromal cells in vitro / 南方医科大学学报

<p><b>OBJECTIVE</b>To investigate the effect of vascular endothelial growth factor 165 (VEGF165) gene transfer on the proliferation and metabolism of human bone marrow stromal cells (hBMSCs) in vitro.</p><p><b>METHODS</b>hBMSCs were divided into 3 groups and subjected to adenovirus mediated VEGF165 gene transfection, transfection with empty adenoviral vector, or left untreated (control). MTT assay and flow cytometry were performed to analyze the proliferation of the cells after corresponding treatments. The third passage of hBMSCs (2x10(4)/ml), after corresponding transfection procedures, were cultured in conditional medium and tested for ALP content 2, 4 and 6 days after the transfection. Also at 3, 5 and 7 days after the transfection, the cells were examined for osteocalcin (C) and laminin (LN) contents.</p><p><b>RESULTS</b>The number of cells in each group increased with the culture time without obvious differences in the optical density. No significant differences were noted between the 3 groups in the percentage of G1 phase cells or in the proliferation index (PrI) (P>0.05), but compared with the nontransfected and the empty vector-transfected cells, the cells with VEGF165 gene transfection had significantly higher ALP, OC and LN contents (P<0.05).</p><p><b>CONCLUSION</b>VEGf165 gene transfer does not obviously affect the proliferation of cultured hBMSCs, but can increase the cellular secretion of AIP, C and LN, suggesting that VEGF165 promotes the differentiation of hBMSCs into osteoblasts in vitro.</p>

Effect of rabbit peripheral sensory and motor nerve homogenates on the proliferation and calcification of rabbit osteoblasts in vitro / 南方医科大学学报

<p><b>OBJECTIVE</b>To investigate the effect of rabbit saphenous and sciatic nerve homogenates on the proliferation and calcification of rabbit osteoblasts in vitro.</p><p><b>METHOD</b>The saphenous nerves (sensory nerves) and the muscular branches of the sciatic nerve (motor nerve) were collected from 48 New Zealand white rabbits to prepare the nerve tissue homogenates. Bone marrow mesenchymal stem cells (MSCs) were isolated from the rabbits and cultured in vitro, and after 14 days of routine osteogenic induction, the resultant osteoblasts were identified by immunohistochemistry, alkaline phosphatase (ALP) and Alizarin red S staining. The osteoblasts were then incubated in the induction medium containing the saphenous (sensory nerve group) or sciatic homogenates (motor nerve group), with the cells in the dexamethasone-containing, dexamethasone-free osteogenic induction medium and control medium as the control. The proliferation, total protein and ALP activity of the osteoblasts were measured every other day until the 8th day, and Alizarin red S staining was used for quantitative analysis of calcification of the cells after two weeks.</p><p><b>RESULTS</b>The application of the saphenous nerve homogenates significantly promoted cell proliferation, total protein and ALP activity (P<0.01, P<0.05 and P<0.05), while exposure of the osteoblasts to dexamethasone inhibited the cell proliferation (P<0.001). Compared to dexamethasone-free group, the saphenous homogenates enhanced the mineralization of the osteoblasts (P<0.001).</p><p><b>CONCLUSION</b>Saphenous nerve homogenates significantly promotes the proliferation, differentiation, ALP activity and mineralization of rabbit osteoblasts, but sciatic nerve homogenates do not show osteogenic effects on the cells.</p>

A study of the different effect on the expression of calcitonin gene related peptide and neuropeptide Y in tissue engineered bone with vascular bundle graft in vivo and that with sensory nerve tract graft in vivo / 中华外科杂志

<p><b>OBJECTIVE</b>To evaluate the different effect on the expression of Calcitonin gene related peptide (CGRP)and neuropeptide Y (NPY) between tissue engineered bone with vascular bundle graft in vivo and that with sensory nerve tract graft in vivo.</p><p><b>METHOD</b>Thirty-six healthy New Zealand rabbits were divided into 3 groups randomly and equally: vascular bundle group (A), sensory nerve tract group (B), tissue-engineering group (C). Group A segmental bone defect of 1.5 cm long was made at the right femur in each animal. After plate fixation, the defects were implanted respectively with the engineered bone prepared in the above-mentioned 3 methods. At 3, 6 and 12 months post-operatively, the distribution of CGRP and NPY in the new bone were detected by immunohistochemistry and analyzed semi-quantitatively by image analysis software.</p><p><b>RESULTS</b>CGRP and NPY immuno-histochemical results indicated their contents increased significantly in all 3 groups as time passed (P = 0.000). Compared with group B, the contents of CGRP and NPY in group A significantly increased at 3 months (P = 0.000), but there was no statistic difference between them at 6 or 12 months (P > 0.05). The expression of CGRP and NPY in both group A and B were significantly more than that in group C at 3, 6 or 12 months (P = 0.000).</p><p><b>CONCLUSION</b>Implantation of vascular bundle into tissue-engineered bone can significantly improve the CGRP and NPY contents at early 3 months comparing with Implantation of sensory tract into tissue-engineered bone, but the changes are not significant at 6 or 12 months post-operatively.</p>

Trauma and pulmonary thromboembolism: an experimental study on their correlation / 中华创伤杂志(英文版)

<p><b>OBJECTIVE</b>To investigate the correlation between trauma and pulmonary thromboembolism.</p><p><b>METHODS</b>Comminuted fractures and extensive soft-tissue contusion at both hind limbs were made by a falling weight from a height in 16 rabbits. Lung perfusion scanning was performed to obtain the radioactivity counts before trauma, at 1 h, 48 h and 96 h after trauma. All the data were divided into 4 groups based on the above 4 time points. The rabbits were sacrificed when positive findings on the pulmonary perfusion scanning appeared. Their lungs were harvested to be paraffin-embedded and stained with hematoxylin-erosin method for histological examination of thromboembolism. The randomized block design ANOVA and the method of least significant difference (LSD) were used for statistical analysis of the radioactivity counts.</p><p><b>RESULTS</b>The histological findings showed that pulmonary embolism developed in 6 of the 16 rabbits (37.5%). Five of the 6 pulmonary embolism rabbits presented neither clinical symptoms nor positive pulmonary embolism manifestations in the lung perfusion scanning. A significant difference was found in lung perfusion radioactivity between the pre-traumatic, post-traumatic 1h groups and post-traumatic 48 h and 96 h groups(P less than 0.05).</p><p><b>CONCLUSIONS</b>Fractures of the hind limbs accompanied with extensive soft-tissue contusion may cause pulmonary micro-embolism that is not sensitive to lung perfusion scanning and tends to have no clinical symptoms. Pulmonary embolism development may take more than two days after trauma.</p>

Landmark-based automatic registration of serial cross-sectional images of Chinese digital human using Photoshop and Matlab software / 南方医科大学学报

This paper describes automatic registration of the serial cross-sectional images of Chinese digital human by projective registration method based on the landmarks using the commercially available software Photoshop and Matlab. During cadaver embedment for acquisition of the Chinese digital human images, 4 rods were placed parallel to the vertical axis of the frozen cadaver to allow orientation. Projective distortion of the rod positions on the cross-sectional images was inevitable due to even slight changes of the relative position of the camera. The original cross-sectional images were first processed using Photoshop software firstly to obtain the images of the orientation rods, and the centroid coordinate of every rod image was acquired with Matlab software. With the average coordinate value of the rods as the fiducial point, two-dimensional projective transformation coefficient of each image was determined. Projective transformation was then carried out and projective distortion from each original serial image was eliminated. The rectified cross-sectional images were again processed using Photoshop to obtain the image of the first orientation rod, the coordinate value of first rod image was calculated using Matlab software, and the cross-sectional images were cut into images of the same size according to the first rod spatial coordinate, to achieve automatic registration of the serial cross-sectional images. sing Photoshop and Matlab softwares, projective transformation can accurately accomplish the image registration for the serial images with simpler calculation processes and easier computer processing.

Distribution and property of nerve fibers in human long bone tissue / 中华创伤杂志(英文版)

<p><b>OBJECTIVE</b>To observe the distribution of the nerve fibers in the bone tissue and the entry points of these fibers into the bone.</p><p><b>METHODS</b>The adult tibia was used for the ground sections which were afterwards made into the slice sections by decalcification in ethylenediamine tetraacetic acid (EDTA). The ground sections were stained in silver and the slice sections were stained in silver and haematoxylin and eosin (HE) respectively. Then, the samples of the transmission electron microscope and the atomic force microscope were made and observed.</p><p><b>RESULTS</b>In the human long bone tissue, many nerve fibers were distributed in the membrane, cortical bone, cancellous bone and marrow. The nerve fibers entered the bone from the nutrient foramen, and passed through the nutrient canal, Haversian's canal and Volkmann's canal, and finally into the bone marrow. In the nutrient canal, the nerve fibers, mainly the medullary nerve fibers, followed the blood vessel into the bone. In the cortical bone, the nerve fibers also followed the blood vessels and were mainly distributed along Haversian's canal and Volkmann's canal. In the bone trabecular and bone marrow, there were many nerve fiber endings arranged around the blood vessels, mainly around the tunica media of medium-size arteries in the marrow and around capillary blood vessels, and a few scattered in the bone marrow. There were sporadic nerve endings in epiphyseal plate and no nerve fibers permeated epiphysis to diaphysis. No distribution of nerve fibers could be found in cartilaginous part.</p><p><b>CONCLUSIONS</b>There are many nerve fibers in bone and the nerve passageway is nutrient foramen, Volkman's canal, Haversian's canal and bone marrow.</p>

Green fluorescent protein as a tracer of bone marrow stromal cells in bone tissue engineering in rhesus / 南方医科大学学报

<p><b>OBJECTIVE</b>To observe the role of green fluorescent protein (GFP) in tracing rhesus bone marrow stromal cells (rBMSCs) during tissue-engineered bone formation in vivo.</p><p><b>METHODS</b>Ad5.CMV-GFP was amplified by infecting QBI-293A cells, and the bone marrow was harvested from the ilium of adult male rhesus to obtain rBMSCs, which were cultured and passaged in vitro. GFP was transfected into the third-passage rBMSCs via adenovirus vector and the labeled cells were inoculated into absorbable HA scaffold and cultured for 3 days, with untransfected rBMSCs as control, before the cell-matrix compounds were implanted into the latissimus dorsi muscles of rhesus. Samples were harvested at 6 week and embedded in paraform, and ground sections of the bone tissue were prepared to observe green fluorescence under laser scanning confocal microscope. Propidium iodide staining of the sections was also performed for observation.</p><p><b>RESULTS</b>The rBMSCs grew well after GFP transfection, and green fluorescence could be seen 24 h after the transfection and became stronger till 48 h, with a positive transfection rate beyond 80%. Six weeks after cell implantation, the rBMSCs labeled by GFP-emitted green fluorescence were detected in the bone tissue under laser scanning confocal microscope.</p><p><b>CONCLUSION</b>GFP can effectively trace BMSCs during bone tissue engineering, and the transplanted BMSCs constitute the main source of bone-forming cells in bone tissue engineering.</p>

Observation of an injectable tissue-engineered bone constructed with autologous platelet-rich plasma and bone marrow stromal cells / 南方医科大学学报

<p><b>OBJECTIVE</b>To construct an injectable tissue-engineered bone graft with fibrin glue (FG), autologous platelet-rich plasma (PRP) and bone marrow stromal cells (BMSCs) cultured in vitro and study its biological characteristics and microscopic structures.</p><p><b>METHODS</b>BMSCs isolated from rabbit iliac bone marrow were culture-expanded in vitro. The injectable tissue-engineered bone constructed from autologous PRP, FG, and BMSCs was cultured in vitro, and its biological characteristics were observed including the time of gel formation, histological features, seed cell survival and microscopic structures.</p><p><b>RESULTS</b>The constructed injectable tissue-engineered bone began gel formation within 20 to 30 s, and after a week-long culture, the gelatine began to degrade, and numerous well viable fusiform cells could be seen to adhere to the bottom of the Petri dish. Scanning electron microscopy identified globular and olivary cells embedded in the fibrin glue, and numerous small particles could be seen around of the cells.</p><p><b>CONCLUSION</b>Construction of an injectable tissue-engineered bone graft with FG, BMSCs and PRP does not require sophisticated techniques and ensures good biological property of the bone graft that can be easily shaped and allow good growth of the seed cells, suggesting great potential of this technique for clinical use.</p>

Observation of the sectional anatomic structure and visualization of the normal lumbar plexus of virtual Chinese human / 中华外科杂志

<p><b>OBJECTIVE</b>To observe the normal structure of lumbar plexus in the virtual Chinese Human (VCH) Female I and Male III and establish a digitized visible model of their lumbar plexus.</p><p><b>METHODS</b>The cross-sectional images from the VCH Female I and Male III dataset were reviewed to study lumbar plexus structures on a section-by-section basis. The nerve roots, major psoas muscle and blood vessels were also observed. Three-dimensional computerized reconstructions of lumbar plexus and its adjacent structures were conducted from these data using Amira 3.1 (TGS) imaging software respectively.</p><p><b>RESULTS</b>The three-dimensional reconstructed visible models perfectly displayed the anatomic relationships of lumbar plexus structures and their adjacent structures.</p><p><b>CONCLUSIONS</b>VCH Female I and Male III dataset can provide complete and accurate data of main structure of lumbar plexus. The digitized models of lumbar plexus offer unique insights into the complex anatomy, and morphologic data for imaging diagnosis and treatment of the injury of lumbar plexus.</p>

Long-term observation of large weight-bearing bone defect in goats repaired with tissue engineering technique / 南方医科大学学报

<p><b>OBJECTIVE</b>To observe the long-term effect of tissue engineering-based repair of large weight-bearing bone defect in goats, and the final outcome of the scaffold material coral hydroxyapatite (CHAP) in vivo.</p><p><b>METHODS</b>Fifteen Chinese goats were subjected to operations to induce a 2-cm left tibial diaphyseal defect, which was filled subsequently with CHAP and bone marrow stromal stem cells (BMSCs). The repaired defects were evaluated by ECT, X-ray and histology in the early stage and at 6, 12, 18, and 24 months postoperatively.</p><p><b>RESULTS</b>ECT showed good bone regeneration and revascularization within 2 months postoperatively. X-ray and histology displayed eccentric and gradual bone regeneration in the early stage, and the tissue-engineered bone graft was firmly healed with the goat tibia. X-ray and histological examination at 6, 12, 18, 24 months postoperatively revealed moulding of the new bones and medullary cavity recanalization, and the structure of CHAP disappeared and gradually integrated into the new bones.</p><p><b>CONCLUSION</b>Tissue-engineered bone is capable of total repair of large bone defect in goats by forming normal functional new bones. CHAP can be eventually degraded completely and become the component of the newly generated bones.</p>

Perfusion-weighted magnetic resonance imaging for monitoring vascularization in tissue-engineered bone in rhesuses / 南方医科大学学报

<p><b>OBJECTIVE</b>To assess the value of perfusion-weighted magnetic resonance (MR) imaging (PWMRI) in monitoring vascularization in tissue-engineered bone graft.</p><p><b>METHODS</b>Tibial diaphyseal defect of 20 mm was induced in 25 lower limbs of 13 rhesuses and fixed with an AO reconstruction plate with 7 holes. The monkeys were randomized into 5 groups according to the materials used for defect filling: group A, with beta-tricalcium phosphate (beta-TCP), bone marrow stromal cells (BMSCs) and blood vessel bundles; group B, with beta-TCP and blood vessel bundles; group C, with beta-TCP and BMSCs; group D, with beta-TCP, and group E without filling. PWMRI, X-ray, and radionuclide imaging were carried out at weeks 4, 8, 12 postoperatively. The maximum slope rates of the single intensity-time curve (SS(max)) and the baseline values (SI(baseline)) on the same time points were calculated. Transmittances on the X-ray films and isotope counts in the region of interest (ROI) were assessed and calculated.</p><p><b>RESULTS</b>Compared with other groups, group A showed the highest SS(max) at weeks 4, 8, and 12 postoperatively, and its SS(max) at week 8 was significantly higher than that at week 4 (P=0.003). The SS(max) was positively related to isotope counts in ROI at week 8 after operation (r(s)=0.899, P=0.038), and inversely related to transmittance on X-ray films at week 12 (r(s)=-0.892, P=0.042).</p><p><b>CONCLUSION</b>The SS(max) of the single intensity-time curve can accurately reflect the vascularization of the tissue-engineered bone graft, and PWMRI allows sensitive, quantitative, noninvasive and radiation-free vascularization monitoring.</p>