An experimental study on the visual identification of Fritillaria ussuriensis based on LAMP and nucleic acid colloidal gold technique.

Fritillaria ussuriensis Maxim is one of the traditional Chinese valuable herbs, which is the dried bulb of Fritillaria, a plant of the lily family. The identification of authenticity about F. ussuriensis is still technically challenging. In this study, visual identification was performed by ring-mediated isothermal amplification and nucleic acid colloidal gold techniques. Firstly, multiple sequence comparative analysis was performed by DNAMAN to find the differential sites of F. ussuriensis and its mixed pseudo-products, and the specific identification primers of F. ussuriensis were designed. Genomic DNA was extracted by the modified CTAB method, and the reaction system and reaction conditions were optimized to construct LAMP for the visual detection of F. ussuriensis, meanwhile, the genuine product was cloned and the extracted plasmid was sequenced. The specificity and sensitivity were detected, and also verified by nucleic acid colloidal gold method, and 20 commercially available samples were tested. The extracted DNA met the requirements of the experiment, and the genuine F. ussuriensis PCR product titrated on a test strip showed two bands on the T and C lines, while the counterfeit and negative control showed only one band on the C line, which matched the LAMP results. The specificity was 100 %, and the sensitivity of LAMP assay was up to 0.01 ng µL-1, while that of colloidal gold assay was 0.1 ng µL-1, thus the LAMP assay had high sensitivity. 14 out of 20 commercially available samples of F. ussuriensis were qualified, and 6 were unqualified, and the results of the two methods of identification were consistent. In this study, the combined detection method of LAMP and colloidal gold for nucleic acid was established to be specific, rapid, precise and visualized, which can provide a new technical idea for the detection of F. ussuriensis.

[Heixiaoyao Powder interferes with microglia polarization in AD model mice by regulating NOX2/ROS/NF-κB signaling pathway].

The effect and mechanism of Heixiaoyao Powder on the polarization of microglia(MG) in APP/PS1 double transgenic mice were explored based on NADPH oxidase 2(NOX2)/reactive oxygen species(ROS)/nuclear factor kappaB(NF-κB) signaling pathway. Fifty 4-month-old male APP/PS1 mice were randomly divided into a model group, an MCC950 group(10 mg·kg~(-1)), and low-, medium-, and high-dose Heixiaoyao Powder groups(6.45, 12.89, and 25.78 g·kg~(-1)). Thirty male C57BL/6J mice of the same age and strain were randomly divided into a blank group, a blank + intragastric intervention group, and a blank + intraperitoneal injection group. Drug intervention lasted 90 days. Morris water maze test was used to detect learning and cognitive ability. Nissl staining and transmission electron microscopy were used to observe the pathological morphology and ultrastructure of hippocampal neurons. Immunofluorescence was used to detect the positive expression of M1-type marker CD16/32~+/Iba-1~+, M2-type marker CD206~+/Iba-1~+ of MG and the expression of hippocampal ROS. The colorimetric method was used to detect the content of malondialdehyde(MDA) and superoxide dismutase(SOD) in the hippocampus. Enzyme linked immunosorbent assay(ELISA) was used to detect the levels of inflammatory factors, including interleukin-6(IL-6), interleukin-8(IL-8), and tumor necrosis factor-α(TNF-α), in the hippocampus. Western blot was used to detect the protein expression of ß-amyloid protein(Aß), Iba-1, CD16/32, CD206, NOX2, NF-κB, p-NF-κB, NF-κB inhibitor alpha(IκBα), and p-IKBα in the hippocampus. The results showed that as compared with the blank group, the model group showed prolonged target quadrant movement distance and escape latency(P<0.01), shortened target quadrant retention time and percentage(P<0.01), disorganized neuronal cells with swelling, nuclear disappearance or bias, reduced number of cells, dissolved or absent Nissl bodies, and a clear area in the cytoplasm, damaged and shrunk cell membrane with abnormal cell morphology, few organelles in the cytoplasm, reduced and swollen mitochondria, increased MG M1-type marker CD16/32~+/Iba-1~+(P<0.01), decreased M2-type marker CD206~+/Iba-1~+(P<0.01), increased ROS activity and MDA content(P<0.01), decreased SOD level(P<0.01), elevated inflammatory factors IL-6, IL-8, and TNF-α(P<0.01), up-regulated protein expression and phosphorylation of Aß, CD16/32, Iba-1, NOX2, NF-κB, and IKBα(P<0.01), and down-regulated CD206(P<0.01). There was no statistically significant difference between the blank group, the blank + intragastric intervention group, and the blank + intraperitoneal injection group. After the intervention of Heixiaoyao Powder, the Heixiaoyao Powder groups showed shortened target quadrant movement distance and escape latency(P<0.01), prolonged target quadrant retention time and percentage(P<0.01), increased and neatly arranged cells with relieved swelling, increased Nissl bodies, regular cell morphology, and intact cell membrane, relieved swelling of mitochondria, slightly expanded endoplasmic reticulum, decreased CD16/32~+/Iba-1~+(P<0.05 or P<0.01), increased CD206~+/Iba-1~+(P<0.01), decreased ROS activity and MDA content(P<0.01), increased SOD level(P<0.01), decreased content of inflammatory factors IL-6, IL-8, and TNF-α(P<0.01), down-regulated protein expression and phosphorylation of Aß, CD16/32, Iba-1, NOX2, NF-κB, and IKBα(P<0.01), and up-regulated CD206(P<0.01). In conclusion, Heixiaoyao Powder can alleviate neuronal damage and improve the learning and memory abilities of APP/PS1 mice. The mechanism of action may be related to the inhibition of NOX2/ROS/NF-κB signaling pathway, regulating the polarization of MG, increasing the expression of M2 type, inhibiting the expression of M1 type, and reducing the release of inflammatory factor.

Structure and Optical Properties of Co-Sputtered Amorphous Silicon Tin Alloy Films for NIR-II Region Sensor.

Near-infrared brain imaging technology has great potential as a non-invasive, real-time inspection technique. Silicon-tin (SiSn) alloy films could be a promising material for near-infrared brain detectors. This study mainly reports on the structure of amorphous silicon tin alloy thin films by Raman spectroscopy to investigate the influence of doped-Sn on an a-Si network. The variations in TO peak caused by the increase in Sn concentration indicate a decrease in the short-range order of the a-Si network. A model has been proposed to successfully explain the non-linear variation in Raman parameters of ITA/ITO and ILA+LO/ITO. The variations of Raman parameters of the films with a higher deposition temperature indicate the presence of SiSn nanocrystals, though the SiSn nanocrystals present no Raman peaks in Raman spectra. XRD and TEM analysis further illustrate the existence of nanocrystals. The ratio of photo/dark conductivity and optical bandgap results demonstrate that the films can be selected as a sensitive layer material for NIR-II region sensors.

A modified technique for tibial bone sparing in unicompartmental knee arthroplasty / 中华医学杂志(英文版)

Background@#Previously, the authors modified the surgical technique to preserve tibial bone mass for Oxford unicompartmental knee arthroplasty (UKA). The purpose of this study was to determine the clinical outcomes and values of this modified technique.@*Methods@#Clinical data of 34 consecutive patients who underwent the unilateral modified UKA technique (modified group, 34 knees) were retrospectively analyzed. To compare the outcome, a match-paired control group (conventional group, 34 knees) of an equal number of patients using the conventional technique system in the same period were selected and matched with respect to diagnosis, age, pre-operative range of motion (ROM), and radiological grade of knee arthrosis. Clinical outcomes including knee Hospital for Special Surgery (HSS) score, ROM, and complications were compared between the two groups. Post-operative radiographic assessments included hip-knee-ankle angle (HKA), joint line change, implant position, and alignment.@*Results@#The mean follow-up time was 38.2 ± 6.3 months. There was no difference in baseline between the two groups. The amount of proximal tibial bone cut in the modified group was significantly less than that of the conventional group (4.7 ± 1.1 mm vs. 6.7 ± 1.3 mm, t = 6.45, P < 0.001). Joint line was elevated by 2.1 ± 1.0 mm in the modified group compared with -0.5 ± 1.7 mm in the conventional group (t = -7.46, P < 0.001). No significant differences were observed between the two groups after UKA with respect to HSS score, VAS score, ROM, and HKA. Additionally, the accuracy of the post-operative implant position and alignment was similar in both groups. As for implant size, the tibial implant size in the modified group was larger than that in the conventional group (χ2 = 4.95, P = 0.035).@*Conclusions@#The modified technique for tibial bone sparing was comparable with the conventional technique in terms of clinical outcomes and radiographic assessments. It can preserve tibial bone mass and achieve a larger cement surface on the tibial side.

A modified technique for tibial bone sparing in unicompartmental knee arthroplasty / 中华医学杂志(英文版)

BACKGROUND@#Previously, the authors modified the surgical technique to preserve tibial bone mass for Oxford unicompartmental knee arthroplasty (UKA). The purpose of this study was to determine the clinical outcomes and values of this modified technique.@*METHODS@#Clinical data of 34 consecutive patients who underwent the unilateral modified UKA technique (modified group, 34 knees) were retrospectively analyzed. To compare the outcome, a match-paired control group (conventional group, 34 knees) of an equal number of patients using the conventional technique system in the same period were selected and matched with respect to diagnosis, age, pre-operative range of motion (ROM), and radiological grade of knee arthrosis. Clinical outcomes including knee Hospital for Special Surgery (HSS) score, ROM, and complications were compared between the two groups. Post-operative radiographic assessments included hip-knee-ankle angle (HKA), joint line change, implant position, and alignment.@*RESULTS@#The mean follow-up time was 38.2 ± 6.3 months. There was no difference in baseline between the two groups. The amount of proximal tibial bone cut in the modified group was significantly less than that of the conventional group (4.7 ± 1.1 mm vs. 6.7 ± 1.3 mm, t = 6.45, P < 0.001). Joint line was elevated by 2.1 ± 1.0 mm in the modified group compared with -0.5 ± 1.7 mm in the conventional group (t = -7.46, P < 0.001). No significant differences were observed between the two groups after UKA with respect to HSS score, VAS score, ROM, and HKA. Additionally, the accuracy of the post-operative implant position and alignment was similar in both groups. As for implant size, the tibial implant size in the modified group was larger than that in the conventional group (χ = 4.95, P = 0.035).@*CONCLUSIONS@#The modified technique for tibial bone sparing was comparable with the conventional technique in terms of clinical outcomes and radiographic assessments. It can preserve tibial bone mass and achieve a larger cement surface on the tibial side.

Glycosaminoglycan Content of the Lateral Compartment Cartilage in Knees Conforming to the Indications for Oxford Medial Unicompartmental Knee Arthroplasty / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>The quality of the lateral compartment cartilage is important to preoperative evaluation and prognostic prediction of unicompartmental knee arthroplasty (UKA). Delayed gadolinium-enhanced magnetic resonance imaging of cartilage (dGEMRIC) enables noninvasive assessment of glycosaminoglycan (GAG) content in cartilage. This study aimed to determine the GAG content of the lateral compartment cartilage in knees scheduled to undergo Oxford medial UKA.</p><p><b>METHODS</b>From December 2016 to May 2017, twenty patients (20 osteoarthritic knees) conforming to the indications for Oxford medial UKA were included as the osteoarthritis (OA) group, and 20 healthy volunteers (20 knees) paired by sex, knee side, age (±3 years), and body mass index (BMI) (±3 kg/m2) were included as the control group. The GAG contents of the weight-bearing femoral cartilage (wbFC), the posterior non-weight-bearing femoral cartilage (pFC), the lateral femoral cartilage (FC), and tibial cartilage (TC) were detected using dGEMRIC. The dGEMRIC indices (T1Gd) were calculated in the middle three consecutive slices of the lateral compartment. Paired t-tests were used to compare the T1Gd in each region of interest between the OA group and control group.</p><p><b>RESULTS</b>The average age and BMI in the two groups were similar. In the OA group, T1Gd of FC and TC was 386.7 ± 50.7 ms and 429.6 ± 59.9 ms, respectively. In the control group, T1Gd of FC and TC was 397.5 ± 52.3 ms and 448.6 ± 62.5 ms, respectively. The respective T1Gd of wbFC and pFC was 380.0 ± 47.8 ms and 391.0 ± 66.3 ms in the OA group and 400.3 ± 51.5 ms and 393.6 ± 57.9 ms in the control group. Although the T1Gd of wbFC and TC tended to be lower in the OA group than the control group, there was no significant difference between groups in the T1Gd in any of the analyzed cartilage regions (P value of wbFC, pFC, FC, and TC was 0.236, 0.857, 0.465, and 0.324, respectively).</p><p><b>CONCLUSIONS</b>The GAG content of the lateral compartment cartilage in knees conforming to indications for Oxford medial UKA is similar with those of age- and BMI-matched participants without OA.</p>

Effects of Lower Limb Alignment and Tibial Component Inclination on the Biomechanics of Lateral Compartment in Unicompartmental Knee Arthroplasty / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Lateral compartmental osteoarthritis (LCOA), a major complication after medial mobile-bearing unicompartmental knee arthroplasty (UKA), is highly associated with the increased stress of the lateral compartment. This study aimed to analyze the effects on the stress and load distribution of the lateral compartment induced by lower limb alignment and coronal inclination of the tibial component in UKA through a finite element analysis.</p><p><b>METHODS</b>Eight three-dimensional models were constructed based on a validated model for analyzing the biomechanical effects of implantation parameters on the lateral compartment after medial Oxford UKA: postoperative lower limb alignment of 3° valgus, neutral and 3° varus, and the inclination of tibial components placed in 4°, 2° valgus, square, and 2° and 4° varus. The contact stress of femoral and tibial cartilage and load distribution were calculated for all models.</p><p><b>RESULTS</b>In the 3° valgus lower limb alignment model, the contact stress of femoral (3.38 MPa) and tibial (3.50 MPa) cartilage as well as load percentage (45.78%) was highest compared to any other model, and was increased by 36.75%, 47.70%, and 27.63%, respectively when compared to 3° varus. In the condition of a neutral position, the outcome was comparable for the different tibial tray inclination models. The inclination did not greatly affect the lateral compartmental stress and load distribution.</p><p><b>CONCLUSIONS</b>This study suggested that slightly varus (undercorrection) lower limb alignment might be a way to prevent LCOA in medial mobile-bearing UKA. However, the inclination (4° varus to 4° valgus) of the tibial component in the coronal plane would not be a risk factor for LCOA in neutral position.</p>

Significance of Lateral Pillar in Osteonecrosis of Femoral Head: A Finite Element Analysis / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>The lateral pillar of the femoral head is an important site for disease development such as osteonecrosis of the femoral head. The femoral head consists of medial, central, and lateral pillars. This study aimed to determine the biomechanical effects of early osteonecrosis in pillars of the femoral head via a finite element (FE) analysis.</p><p><b>METHODS</b>A three-dimensional FE model of the intact hip joint was constructed from the image data of a healthy control. Further, a set of six early osteonecrosis models was developed based on the three-pillar classification. The von Mises stress and surface displacements were calculated for all models.</p><p><b>RESULTS</b>The peak values of von Mises stress in the cortical and cancellous bones of normal model were 6.41 MPa and 0.49 MPa, respectively. In models with necrotic lesions in the cortical and cancellous bones, the von Mises stress and displacement of lateral pillar showed significant variability: the stress of cortical bone decreased from 6.41 MPa to 1.51 MPa (76.0% reduction), while cancellous bone showed an increase from 0.49 MPa to 1.28 MPa (159.0% increase); surface displacements of cortical and cancellous bones increased from 52.4 μm and 52.1 μm to 67.9 μm (29.5%) and 61.9 μm (18.8%), respectively. In addition, osteonecrosis affected not only pillars but also adjacent structures in terms of the von Mises stress and surface displacement levels.</p><p><b>CONCLUSIONS</b>This study suggested that the early-stage necrosis in the femoral head could increase the risk of collapse, especially in lateral pillar. On the other hand, the cortical part of lateral pillar was found to be the main biomechanical support of femoral head.</p>

Glucocorticoids Significantly Influence the Transcriptome of Bone Microvascular Endothelial Cells of Human Femoral Head / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Appropriate expression and regulation of the transcriptome, which mainly comprise of mRNAs and lncRNAs, are important for all biological and cellular processes including the physiological activities of bone microvascular endothelial cells (BMECs). Through an intricate intracellular signaling systems, the transcriptome regulates the pharmacological response of the cells. Although studies have elucidated the impact of glucocorticoids (GCs) cell-specific gene expression signatures, it remains necessary to comprehensively characterize the impact of lncRNAs to transcriptional changes.</p><p><b>METHODS</b>BMECs were divided into two groups. One was treated with GCs and the other left untreated as a paired control. Differential expression was analyzed with GeneSpring software V12.0 (Agilent, Santa Clara, CA, USA) and hierarchical clustering was conducted using Cluster 3.0 software. The Gene Ontology (GO) analysis was performed with Molecular Annotation System provided by CapitalBio Corporation.</p><p><b>RESULTS</b>Our results highlight the involvement of genes implicated in development, differentiation and apoptosis following GC stimulation. Elucidation of differential gene expression emphasizes the importance of regulatory gene networks induced by GCs. We identified 73 up-regulated and 166 down-regulated long noncoding RNAs, the expression of 107 of which significantly correlated with 172 mRNAs induced by hydrocortisone.</p><p><b>CONCLUSIONS</b>Transcriptome analysis of BMECs from human samples was performed to identify specific gene networks induced by GCs. Our results identified complex RNA crosstalk underlying the pathogenesis of steroid-induced necrosis of femoral head.</p>

Finite Element Analysis of Mobile-bearing Unicompartmental Knee Arthroplasty: The Influence of Tibial Component Coronal Alignment / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Controversies about the rational positioning of the tibial component in unicompartmental knee arthroplasty (UKA) still exist. Previous finite element (FE) studies were rare, and the results varied. This FE study aimed to analyze the influence of the tibial component coronal alignment on knee biomechanics in mobile-bearing UKA and find a ration range of inclination angles.</p><p><b>METHODS</b>A three-dimensional FE model of the intact knee was constructed from image data of one normal subject. A 1000 N compressive load was applied to the intact knee model for validating. Then a set of eleven UKA FE models was developed with the coronal inclination angles of the tibial tray ranging from 10° valgus to 10° varus. Tibial bone stresses and strains, contact pressures and load distribution in all UKA models were calculated and analyzed under the unified loading and boundary conditions.</p><p><b>RESULTS</b>Load distribution, contact pressures, and contact areas in intact knee model were validated. In UKA models, von Mises stress and compressive strain at proximal medial cortical bone increased significantly as the tibial tray was in valgus inclination >4°, which may increase the risk of residual pain. Compressive strains at tibial keel slot were above the high threshold with varus inclination >4°, which may result in greater risk of component migration. Tibial bone resection corner acted as a strain-raiser regardless of the inclination angles. Compressive strains at the resected surface slightly changed with the varying inclinations and were not supposed to induce bone resorption and component loosening. Contact pressures and load percentage in lateral compartment increased with the more varus inclination, which may lead to osteoarthritis progression.</p><p><b>CONCLUSIONS</b>Static knee biomechanics after UKA can be greatly affected by tibial component coronal alignment. A range from 4° valgus to 4° varus inclination of tibial component can be recommended in mobile-bearing UKA.</p>

A method for isolated culture of bone microvascular endothelial cells of human femoral head / 中国骨伤

<p><b>OBJCETIVE</b>To investigate the method of separation of culture of bone microvascular endothelial cells (BMECs) of human femoral head in vitro.</p><p><b>METHODS</b>From October 2013 to January 2014,15 femoral heads without pathologic change from patients resected during hip replacement were selected involving 2 males and 13 females with a mean age of 71.2 years old ranging from 38 to 92. Cancellous bone in femoral head was bited into broken bone grain and transfered into medium in aseptic contidion. Cells were isolated by the methods of enzymic digestion and density gradient centrifugation,purified by differiential attachment. The characteristics of cells was observed by inverted microscope. vWF and CD31 immunofluorescence analysis was applied for identification of cells.</p><p><b>RESULTS</b>The number of cells was positively correlated with patients' age after 24 hours in primary culture. The older patients had the less cells numbered. After 4 to 5 days' culture, primary cells appeared short spindle,polygon shaped and cobblestone-like morphology. After 7 to 10 days' culture, primary cells proliferated densely, became fusion, arranged in swirl, and contact inhibition appeared significantly. Immunofluorescence staining revealed the cells were 100% positive for vWF and CD31, and it showed that the cultured cells were BMECs.</p><p><b>CONCLUSION</b>It was a simple, steady, effective method with good reproducibility, by which highly purified human BMECs can be obtained.</p>

Progress of mechanotransduction in differentiation of bone marrow mesenchymal stem cells mediated by cellular mechanosensor and TNTs / 医用生物力学

With the regulation of mechanical microenvironment being realized as an important role playing in the differentiation of bone marrow mesenchymal stem cells (BMSCs), the systematic researches on stem cells are gradually deepened into the extended cellular biomechanical field, which lead to a hot research focus on cellular biomechanical properties, basic mechanical structure units and network-like mechanical architecture among cells. In this paper the analysis on mechanical properties of BMSCs and mechanical molecular basic research on integrins and cadherins are reviewed, and the main frame of network like mechanical regulation is speculated and constructed, combined with the internal bony structure and mechanical geometric properties of the tunneling nanotubes (TNTs). The possibility of synergistic effect among the above important mechanical structures in the network-like mechanical microenvironment is also investigated.

Formative mechanism of intracanal fracture fragments in thoracolumbar burst fractures: a finite element study / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Thoracolumbar burst fracture is a common clinical injury, and the fracture mechanism is still controversial. The aim of this research was to study the formation of intracanal fracture fragments in thoracolumbar burst fractures and to provide information for the prevention of thoracolumbar bursts fractures and reduction of damage to the nervous system.</p><p><b>METHODS</b>A nonlinear three-dimensional finite element model of T11-3 segments was established, and the injury processes of thoracolumbar bursts were simulated. The intact finite element model and the finite element model after the superior articular were impacted by 100 J of energy in different directions. The distribution and variation of stress in the superior posterior region of the L1 vertebral body were analyzed. Abaqus 6.9 explicit dynamic solver was used as finite element software in calculations.</p><p><b>RESULTS</b>A three-dimensional nonlinear finite element model of the thoracolumbar spine was created. In the intact model, stress was concentrated in the superior posterior region of the L1 vertebral body. The stress peak was a maximum for the extension impact load and a minimum for the flexion impact load. The stress peak and contact force in the facet joint had close correlation with time. The stress peak disappeared after excision of the superior articular process.</p><p><b>CONCLUSIONS</b>The three-dimensional nonlinear finite element model was suitable for dynamic analysis. The contact force in the facet joint, which can be transferred to the superior posterior vertebral body, may explain the spinal canal fragment in thoracolumbar burst fractures.</p>

Unilateral pedicle screw fixation through the pedicle of fractured vertebra in combination with the short segment of pedicle screw in the treatment of thoracolumbar fracture of mild to moderate instability / 中华外科杂志

<p><b>OBJECTIVE</b>To evaluate the efficacy of unilateral pedicle screw fixation through the pedicle of fractured vertebra in combination with the short segment of pedicle screw in the treatment of thoracolumbar fracture of mild to moderate instability.</p><p><b>METHODS</b>Twenty-six patients with single segment thoracolumbar fracture received unilateral pedicle screw fixation through the pedicle of fractured vertebra in combination with the short segment of pedicle screw from January 2008 to December 2009. There were 16 patients were male and 10 were female with an average age of 47.3 years (range from 39 to 60 years). Fracture severity score was constructed by using the load-sharing classification (4 points for 2 cases, 5 points for 14 cases, 6 points for 10 cases). By Frankel assessment system, 2 cases were in grade C, 3 in grade D, 21 in grade E. The assessment included anterior vertebral body height, the sagittal Cobb angle, the restoration of nervous function, visual analogue score (VAS) and Oswestry disability index (ODI).</p><p><b>RESULTS</b>The follow-up after the surgery was 13 - 26 months, with an average of 18.6 months. There were no fixation failure, defined as implant failure or ≥ 10° correction loss. The neurological status of 4 patients, who had an associated neurologic deficit preoperatively, was completely recovered. The Frankel grade of another case was re-rated D from the original C. The mean anterior vertebral body height increased from 57.0% ± 6.3% before the surgery to 93.1% ± 1.7% at the last follow-up(F = 455.276, P < 0.05). The sagittal Cobb angle decreased from 15.6° ± 4.7° before the surgery to 2.6° ± 5.2° at the last follow-up (F = 34.623, P < 0.05). VAS and ODI were 1.0 ± 0.7 and 17.0 ± 5.9 at the last follow-up.</p><p><b>CONCLUSION</b>Unilateral pedicle screw fixation through the pedicle of fractured vertebra combined with the short segment of pedicle screw is effective for thoracolumbar fracture with mild to moderate instability.</p>

Identification and molecular characterization of antimicrobial-resistant shiga toxin-producing Escherichia coli isolated from retail meat products.

Ten (2.7%) Shiga toxin-producing Escherichia coli (STEC) were isolated from 370 samples of raw minced beef, mutton, pork, and chicken from the Jilin region of China; and additional 10 E. coli O157:H7 isolates were previously isolated from different Jilin regions. Seventeen of the isolates were multiresistant, exhibiting resistance to ampicillin, ciprofloxacin, tetracycline, sulfamethoxazole-trimethoprim, gentamycin, and streptomycin. Class 1 integrons were detected in nine (45.0%) of the STEC isolates and consisted of serogroups O157, O62, O113, O149, and O70. Integrons containing amplicons of a 0.5-1.5 or 1.0 kb gene cassette were found in seven (77.8%) of the integron-containing isolates. Sequencing analysis revealed that these gene cassettes encode genes conferring resistance to trimethoprim (dfrA1) and streptomycin (aadA1). The 0.5 kb cassette described here was found to encode a putative transporter peptide in the STEC. Seventeen isolates contained plasmids with different bands, and transfer by conjugation between strains of E. coli demonstrated that class 1 integrons located on mobile plasmids could contribute to the emergence and dissemination of antimicrobial resistance to ampicillin, gentamycin, streptomycin, and sulfamethoxazole-trimethoprim amongst STEC. These data revealed the high prevalence of antimicrobial-resistant STEC isolates in Jilin's surrounding regions, providing important and useful surveillance information reflecting antimicrobial selection pressure.

Experimental study on the induced differentiation of human amnion mesenchymal cells into osteoblasts / 中华整形外科杂志

<p><b>OBJECTIVE</b>To investigate the feasibility of inducing differentiation of the human amniotic mesenchymal cells (hAMCs) into osteoblasts in vitro, so as to provide the seed cells for bone tissue engineering.</p><p><b>METHODS</b>The hAMCs were isolated from abandoned human amnion and cultured in osteogenic media to induce the osteogenic differentiation in vitro. After hAMCs were induced by osteogenic media for 15 days, morphological observation, immunocytochemistry and western blot were used to study the cellular morphology and expression of alkaline phosphatase (ALP), type I collagen, osteopontin and osteocalcin.</p><p><b>RESULTS</b>The primary cultured hAMCs had long spindle shape or irregular shape, which were distributed evenly. The cells were usually suheultured in 5 or 7 days. After subculture, the cells became larger. After cultured by osteogenic media for 15 days, the hAMCs were detected to express ALP, osteocalcin and osteopontin, and secrete type I collagen.</p><p><b>CONCLUSIONS</b>The hAMCs are isolated, cultured and amplified easily in vitro. The induced differentiated cells by osteogenic media have typical osteoblast morphological and functional characteristics, which can be used as seed cells for bone tissue engineering.</p>

Study on the relationship between sclerosis rim and bone morphogenetic proteins of osteonecrosis of the femoral head / 中华外科杂志

<p><b>OBJECTIVES</b>To analyze retrospectively the formation and histological changes of sclerosis rim in patients with osteonecrosis of the femoral head (ONFH), and to study the relationship between bone morphogenetic proteins (BMP4) and sclerosis rim, so as to acquire experimental and theoretical basis on individualized treatment for ONFH patients.</p><p><b>METHODS</b>From November 2005 to November 2007, 184 hips of steroid-induced ONFH inpatients were collected. The mean age was (47 ± 7) years, the patients were divided into high (more than 54 years old), middle (40 - 54 years old) and low (less than 40 years old) age groups. Their clinical data were analyzed retrospectively according to gender and age. Parts of the femoral heads were selected for the study, including 18 hips in high age group, 11 hips in low age group and 20 hips in middle age group. Each 10 hips were selected with or without sclerosis rim. The femoral heads were cut along middle coronal plane, their weight-bearing and non-weight-bearing areas were used for the study. The specimens were processed by routine HE staining and picric acid-Sirius red staining and electron microscopy preparation and immunohistochemistry stain. The average optical density of BMP4 protein was calculated by image analysis software.</p><p><b>RESULTS</b>The trabecular of sclerosis rim was thickening and disorder. But its osteocytes were normal and with high secretion. The ratio of sclerosis rim was 71.4% (105/147) in middle age ONFH patients, which was significantly higher than the low age group patients (45.5%, 5/11) and high age group patients (38.5%, 10/26) (P < 0.01). The optical density of BMP4 in middle age ONFH patients was 0.32 ± 0.14, which was significantly higher than the low age group 0.20 ± 0.17 and high age patients 0.19 ± 0.27 (P < 0.05). The optical density was 0.16 ± 0.11 in ONFH patients without sclerosis rim, which was significantly lower than with sclerosis rim (0.28 ± 0.13) (P < 0.01). The time from hip pain to joint replacement in patients with sclerosis rim was (49 ± 11) months, and (15 ± 2) months without sclerosis rim. There was significant difference between the two groups (P < 0.01).</p><p><b>CONCLUSIONS</b>The formation of sclerosis rim is positively related to the expression of BMP4, and high expression of BMP maybe promote the formation of sclerosis rim.</p>

A finite element analysis of the pelvic reconstruction using fibular transplantation fixed with four different rod-screw systems after type I resection / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>The pelvis often needs to be reconstructed after bone tumor resection. A major challenge here for the orthopedic surgeons is to choose a method that gives the best performance which depends upon its biomechanical properties. In this study, a 3-dimensional finite element analysis (FEA) was used to analyze the biomechanical properties of reconstructed pelvis using fibula transplant fixed by four commonly used rod-screw systems.</p><p><b>METHODS</b>A total pelvic finite-element model including the lumbar-sacral spine and proximal femur was constructed based on the geometry of CT image from a healthy volunteer. Three-dimensional finite element models of different implants including fibula, rod and screw were simulated using ways of solid modeling. Then various reconstructed finite element models were assembled with different finite element implant model and type I resected pelvic finite element model. The load of 500 N was imposed vertically onto the superior surface of L3 vertebral body, and the pelvis was fixed in bilateral leg standing positions. FEA was performed to account for the stress distribution on the bones and implants. The pelvis displacement of the different rod-screw fixation methods and the maximum equivalent stress (max EQV) on all nodes and element were figured out to evaluate the advantages and disadvantages of different reconstructive methods.</p><p><b>RESULTS</b>Stress concentration in the fibula transplant was extremely high in the reconstructed pelvis, but could be substantially decreased by internal fixation, which partially transferred the stress from the fibula to the rod-screw systems. High stress concentration was also found in the implants, especially in the connection sites between screw and rod. Among the four methods of fixation, a double rod system with L5-S1 pedicle and ilium screws (L5-S1 HR) produced the best performance: least stress concentrations and least total displacement.</p><p><b>CONCLUSION</b>According to the stability and stress concentration, the method of L5-S1 HR fixation combined with fibula transplantation is better than other fixation methods in pelvic reconstruction after type I resection.</p>

Measuring blood flow change of osteonecrosis of femoral head with laser doppler flowmetry / 中华外科杂志

<p><b>OBJECTIVE</b>To detect the blood perfusion of the necrotic area and the femoral head and neck junction in the patients diagnosed as osteonecrosis of femoral head (ONFH) with laser doppler flowmetry (LDF).</p><p><b>METHODS</b>From 2007 to 2008, 50 patients with ONFH 82 hips were performed core decompression and autologous stem cells transplantation. Group A was for ARCO stage II 46 hips (IIA 6 hips, IIB 22 hips, IIC 18 hips), and Group B was for stage III 36 hips (IIIA 20 hips, IIIB 10 hips, IIIC 6 hips). Blood perfusion of necrotic area and femoral head and neck junction with LDP were detected during the operation. Statistical analysis was made.</p><p><b>RESULTS</b>In Group A, the perfusion volume of necrotic area was (30.2 +/- 3.0) PU, and the perfusion volume of femoral head and neck junction was (103.4 +/- 4.4) PU. In Group B, the perfusion volume of necrotic area was (30.6 +/- 2.8) PU, and the perfusion volume of femoral head and neck junction was (103.4 +/- 3.9) PU. In Group A and Group B, the perfusion volume of necrotic area was lower than that of femoral head and neck junction, and the difference was significant (P < 0.01).</p><p><b>CONCLUSIONS</b>LDF can effectively detect that the perfusion volume of ONFH decreased, which provides a theoretical basis in order to further study the pathogenesis of ONFH. Meanwhile, there is application value of LDF on the study of ONFH.</p>

Analysis of the pelvic stability after type I resection of iliac tumor / 中华外科杂志

<p><b>OBJECTIVE</b>To analyze the pelvic stability after type I resection of iliac tumor.</p><p><b>METHODS</b>Six adult cadaveric specimens were tested. The iliac subtotal resection models were established according to Ennecking's type I resection. Markers were affixed to the key region of the pelves. Axial loading from the proximal lumbar was applied by MTS load cell in the gradient of 0-500 N in the double feet standing state. Images in front view were obtained using CCD camera. Based on Image J software, displacements of the first sacral vertebrae (S1) of the resected pelves and the intact pelves were calculated using digital marker tracing method with center-of-mass algorithm.</p><p><b>RESULTS</b>Serious instabilities were found in the resected pelves. S1 rotational movements around the normal side femoral head of the resected pelvis were found. The average vertical displacement of S1 of the resected pelvis was (7 +/- 3) mm under vertical load of 500 newtons, which were 8.3 times compared to the intact pelvis. The average angle of S1 rotation around the normal side femoral head of the resected pelvis was (4.0 +/- 1.8) degrees, which were 12.5 times compared to the intact pelvis.</p><p><b>CONCLUSIONS</b>Biomechanical model of type I resection of iliac tumor are established. Essential pelvic reconstruction must be introduced because of the serious instability of the bone defection after tumor resection.</p>