Research Progress on Regulation of Macrophage Polarization by Biomaterial Functionalized Surface / 医用生物力学

Prosthetic loosening and periprosthetic inflammation, as serious complications after joint replacement surgery, often require the secondary surgery for repair, which is easy to adversely affect the physical/mental health and economic status of patients.Studies have shown that the functional phenotype expressed by macrophages by different stimuli, namely macrophage polarization state, prolonged M1 polarization can lead to the continuation of long-term inflammation, while timely and effective M2 macrophage phenotype will lead to enhanced osteogenesis and tissue remodeling cytokine secretion and subsequent osseointegration, which play a crucial role in the development and outcome of prosthetic loosening and periprosthetic inflammation.The local micro-environment of extracellular matrix (ECM) is an important factor in the activation, migration, proliferation and fusion of macrophages. Researchers have deeply understood it mainly through the crosstalk between surface properties of biomaterials and macrophages. As an effector cell, macro-phages can perform complex spatiotemporal cellular functional responses by sensing the physical and chemical environment (surface topography, wettability, chemical composition, biological proteins) represented by surface properties of biomaterials.This paper summarizes the recent findings on macrophage polarization and material surface properties.

Research Advances in the Effect of Mechanical Regulation of Long-Chain Non-Coding RNAs on Osteogenic Differentiation of Mesenchymal Stem Cells / 医用生物力学

With the development of the 3rd-generation high-throughput sequencing technology and tissue engineering, recent studies show that many long-chain non-coding RNAs (LncRNAs) have played an important role in osteogenic differentiation of mesenchymal stem cells (MSCs). LncRNAs, which are involved in the regulation of mechanical regulation, further regulate bone-related cell functions and play a regulatory role at multiple levels, including transcription, post-transcriptional and epigenetic. LncRNAs may be involved in the osteogenic differentiation and bone remodeling of MSCs, the regulation of bone-related cell functions as a mechanical response molecule, as well as the pathological process of skeletal diseases.

Multidimensional Structure and Properties of Silk Fibroin/Collagen/Hydroxyapatite Bionic Bone Materials / 医用生物力学

Objective To construct a two-dimensional (2D) composite membrane and a three-dimensional (3D) biomimetic scaffold by silk fibroin (SF), type I collagen (Col-I) and hydroxyapatite (HA) blends in vitro, so as to study its physicochemical properties, as well as biocompatibility and explore the feasibility of its application in tissue engineering scaffold materials. Methods 2D composite membranes and 3D scaffolds were prepared by blending SF/Col-I/HA at the bottom of cell culture chamber and low temperature 3D printing combined with vacuum freeze drying. The biocompatibility was evaluated by mechanical property testing, scanning electron microscope and Micro-CT to examine the physicochemical properties of the material, and cell proliferation was detected to evaluate its biocompatibility. Results Stable 2D composite membrane and 3D porous structural scaffolds were obtained by blending and low temperature 3D printing. The mechanical properties were consistent. The pore size, water absorption, porosity and elastic modulus were all in accordance with the requirements of constructing tissue engineering bone. The scaffold was a grid-like white cube with good internal pore connectivity; HA was evenly distributed in the composite membrane, and the cells were attached to the composite membrane in a flat shape; the cells were distributed around pore walls of the scaffold. The shape of the shuttle was fusiform, and the growth and proliferation were good. Conclusions The composite membrane and 3D scaffold prepared by SF/Col-I/HA blending system had better pore connectivity and pore structure, which was beneficial to cell and tissue growth and nutrient transport. Its physicochemical properties and biocompatibility could meet the requirements of bone tissue engineering biomaterials.

Hypothermia regulates the internal environment following spinal cord injury: the underlying mechanisms / 中国组织工程研究

BACKGROUND: Spinal cord injury is a damage to the spinal cord with a high morbidity that can be divided into primary and secondary injury. Secondary injury does more harm to the body than primary injury, which can be regulated and improved through proper interventions. In addition to the drugs, surgical decompression and other traditional treatments, hypothermia is an important physical intervention that has been shown to regulate secondary injury following spinal cord injury, and hold neuroprotective effect.OBJECTIVE: To introduce different hypothermia treatments for spinal cord injury and the effect on the disordered environment after spinal cord injury, as well as summarize the latest progression. METHODS: A computer-based search of CNKI and PubMed databases was conducted for the articles addressing the application of hypothermia in spinal cord injury published from January 2001 to June 2016, using the keywords of therapeutic hypothermia or low temperature, spinal cord injury in Chinese and English, respectively. RESULTS AND CONCLUSION: Hypothermia is divided into systematic and local hypothermia, and the former is simple and convenient, but it may lead to complications. Local hypothermia can quickly reach the target temperature, to make deep hypothermia at injury site and stablize the core temperature in the body, but it is invasive, and the necessary time of locating and maintaining effective temperature is a challenge. In general, hypothermia can improve the disordered microenvironment after spinal cord injury, reduce inflammatory infiltration, regulate the expression of relative genes and proteins, and promote the proliferation and differentiation of endogenous nerve cells. There are basic and clinical studies on hypothermia neuroprotection against spinal cord injury from various aspects; thereafter, hypothermia is a promising treatment strategy for spinal cord injury.

Collagen/silk fibroin nerve conduits used for repairing peripheral nerve defect:application and development / 中国组织工程研究

BACKGROUND:Peripheral nerve defect due to limb dysfunction has always been the difficulty faced by the medical profession. Ideal materials and processing technology for constructing a tissue engineering scaffold targeting peripheral nerve repair are stil in research stage. OBJECTIVE:To review the research progress in peripheral nerve repair using col agen/silk fibroin nerve conduits. METHODS:In this paper, the first author retrieved the PubMed and CNKI from 2003 to 2016 to search articles regarding methods of constructing artificial nerve scaffolds and selection of raw materials. Data from these articles were col ected, summarized and analyzed. RESULTS AND CONCLUSION:Forty-six articles were included for final analysis. Col agen and its degradation products trigger no inflammatory response in the host because of high biocompatibility and biodegradability. However, its use is largely limited by its rapid degradation and poor physical performance. Silk fibroin has a high flexibility and biocompatibility, and exhibits a slow degradation in vivo. As a rapid prototyping technique, three-dimensional printing can print various forms of scaffolds within a short time, characterized as high-quality pore structure and large-scale production. Given these, the col agen/silk fibroin nerve conduit prepared using the three-dimensional printing technology can maintain the biocompatibility and even improve the mechanical properties of the raw materials. Until now, more investigations on nerve repair using col agen or silk fibroin have been done, and we have never stopped improving the production process of these scaffolds. Therefore, the col agen/silk fibroin scaffold prepared using the three-dimensional printing technology is expected to become the main candidate for the repair of peripheral nerve defects.

Spinal cord transection in a spinal cord injury model established using accurate micrological technique / 中国组织工程研究

BACKGROUND: Diffusion tensor imaging is a common technique applied for clinical studies of the brain, but it is rarely used for the diagnosis or prognosis of spinal cord injury. OBJECTIVE: To establish a rat model of spinal cord injury using micrological techniques, and to evaluate spinal cord transection with diffusion tensor imaging technology, thus providing a good animal model for further intervention. METHODS: Twelve healthy Sprague-Dawley rats were applied to establish spinal cord injury models using precise microscopic techniques, and another six rats in the sham operated group served as controls. Spinal cord transection of experimental rats after modeling was observed using diffusion tensor imaging. Motor evoked potentials and somatosensory evoked potentials were used to detect electrical physiological changes of rats.Neurological function changes of rats were evaluated using slope experiments and Basso, Beattie and Bresnahan scores. RESULTS AND CONCLUSION: After experimental rats regained consciousness, their lower extremities exhibited complete paralysis, the tails cannot swing, accompanying urinary retention. Diffusion tensor imaging displayed the T10 segment of spinal cord was completely transected. Motor and sensory evoked potential waveform were not drawn compared than control group. At 1 day, 1 week, 2 weeks, 4 weeks after operation, the test angle of slope experiments was less than 30° and Basso, Beattie and Bresnahan score was less than 10 points; as the time prolonged, lower limb irritating reflections of some rats were visible, but no initiative functional activity was found, local spinal cord structure were severely damaged. Precise microscopic techniques can successfully establish spinal cord injury model in rats, and diffusion tension imaging clearly visualizes the complete transection of the T10 spinal cord.

Clinical significance of peripheral blood circular DNA level measurements in patients with acute myocardial infarction / 中国医疗器械杂志

<p><b>OBJECTIVE</b>To explore clinical value of circular DNA in acute myocardial infarction.</p><p><b>METHODS</b>Venous blood (2 ml/head) of 40 healthy control and 40 patients with acute myocardial infarction within 48h of onset of illness and convalescent period was collected. The level of plasma circular DNA was detected by duplex real-time polymerase chain reaction assay. The levels of myocardial enzyme spectrum and cardiac troponin T (cTnT) were detected by biochemistry method.</p><p><b>RESULTS</b>The level of circular DNA in control group and group of acute myocardial infarction before treatment was (21.5 +/- 10.7) ng/ml and (253.6 +/- 45.7) ng/ml, respectively (P = 0.000). The levels of serum myocardial enzyme spectrum and cTnT before treatment in patients with acute myocardial infarction were significantly higher than those of control group (P < 0.05). The level of circular DNA after treatment in patients with acute myocardial infarction was significantly decreased compared with that before treatment (P = 0.000), the levels of myocardial enzyme spectrum and cTnT were also significantly reduced (P < 0.05). There was significant correlation between the level of circular DNA and those of CK-MB and cTnT, r = 0.613, 0.654, P = 0.032, 0.021.</p><p><b>CONCLUSION</b>Circular DNA can be used as a marker of sensitively reflecting myocardial cell injury.</p>

The clinical features and treatment strategies of thoracic ossification of posterior longitudinal ligament / 中华骨科杂志

Objective To study the clinical features and surgical strategies of thoracic spinal stenosis caused by ossification of posterior longitudinal ligament(OPLL).Methods From January 2004 to March 2009,21 cases of thoracic spinal stenosis casued by OPLL,including 13 males and 8 females,received surgical treatments.Those cases aged from 34 to 71 years,with an average of 51.2 years old.The courses of disease were from 2 to 50 months,averaged 11 months.The lesions located in upper thoracic(T1-T4)for 4 cases,in middle thoracic(T5-T8)for 7 cases,in lower thoracic(T9-T12)for 10 cases.Nine cases were associated with ossification of ligamentum flavum(OLF),and 8 cases combined with cervical OPLL.Eleven cases received laminectomy and 10 cases received anterolateral decompression.Results The operation time was 90 to 240 min for posterior laminectomy with an average of 140 min,and 110 to 360 min for anterolateral decompression with an average of 240 min.All cases had no worse postoperative symptoms,neurological complications,subarachnoid cavity or wound infection.Japanese Orthopaedic Association(JOA)score was 8 to 15 with an average of 9.17±1.63 in 6 months after surgery.Nerve function improvement was excellent for 8 cases,good for 6 cases,fair for 5 cases and poor for 2 cases.The excellent and good rate was 66.7%.JOA score was 8-15,averaged 10.23±1.64,in 12 months after surgery.Nerve function improvement was excellent for 8 cases,good for 7 cases,fair for 4 cases,and poor for 2 cases.The excellent and good rate was 71.4%.Conclusion Thoracic spinal stenosis result from OPLL,which often combine with cervical OPLL and OLF,often show multiple manifestations.Posterior laminectomy and anterolateral decompression are suitable for those conditions.

Development of fluorescence quantitative PCR for detection of Bordetella pertussis and its application / 中华检验医学杂志

Objective To establish a rapid,accurate,specific quantitative assay for detecting B.pertussis,and apply to clinical diagnosis.Methods According to the specific sequence of B.pertussis IS481 gene,the primers and the fluorescence probe were designed and synthesized.Then a fluorescence quantitative PCR for detecting B.pertussis was developed.The specificity,sensitivity and reproducibility of the method were evaluated.255 specimens including 225 nasopharyngeal swabs from suspected pertussis patients and 30 normal nasopharyngeal swabs were detected by fluorescence quantitative PCR.Results A rapid specific quantitative method for detecting B.pertussis was established.The standard curve of the method indicated that there was a good linear relationship between the CT value and the template concentration with the correlation coefficient being 0.998.The linear range of the system was from 102 to 108 copies/μl and the minimum was 102 copies.It had a high sensitivity and good specificity.The intra.and inter-assay coefficients of variation were 5.78%-16.7% and 8.25%-14.9% respectively.The fluorescence quantitative PCR identified 41 positive results for specimens from suspected pertussis patients and results of 30 normal specimens were all negative.Conclusions The method can quantitatively detect the B.pertussis rapidly with high sensitivity and specificity,it can be applied to clinical diagnosis.

Axonal regeneration promotion by chondroitinase ABC after spinal cord injury in rats / 中国矫形外科杂志

[Objective]To investigate the effect of chondroitinase ABC(ChABC) after spinal cord injury(SCI) in adult rats,and to evaluate the significance of treatment. [Methods]Forty adult Wistar rats were divided into two groups: the control group(group A),the chondroitinase ABC group(group B).The thoracic T10 spinal cord injury model was made by impactor model II manual.After SCI,group B animals received ChABC treatment,while group A animals only received blank saline.The locomotor functions(BBB score) and the neuroelectrophysiological changes(SEP&MEP) of the rats were evaluated.Twelve weeks after SCI,biotinylated dextran amine(BDA) was injected into the cerebral cortex to trace the corticospinal tracts(CST).Then two weeks after the tracing,the animals were killed and the spinal cord frozen sections were made.The tissue sections were processed with Cy3 fluorescence stain,HE stain and anti NF-200 immuohistological stain.The section images were analyzed by Image Pro Plus image analyzing software.All the statistics were performed by SPSS 13.0 software.[Results]At 4 weeks after SCI,group B had obvious higher BBB scores than control group(P