Biomechanical Study of PEEK Condyle Prosthesis Printed by Fused Deposition Modeling and Selective Laser Sintering / 医用生物力学

Objective To make finite element analysis and compressive performance test on three-dimensional (3D) printed personalized poly-ether-ether-ketone (PEEK) condyle prosthesis, so as to analyze stress distribution characteristics and mechanical properties of the prosthesis, and to evaluate its clinical value and prospect. Methods The finite element models of PEEK condyle prosthesis, mandible and fixation screw were established by software such as CBCT, Mimics, Geomagic Studio, SolidWorks and ANSYS Workbench. The maximum mastication force was applied, and the maximum stress of the condyle prosthesis and screw, as well as the stress and strain of the mandible were recorded. In order to simulate the actual clinical situation, a special fixture was designed to test compression performance of the condyle prosthesis prepared by the fused deposition modeling (FDM) and selective laser sintering (SLS) at the rate of 1 mm/min. Results The peak stress of the PEEK condyle prosthesis was 10.733 MPa, which was located at the back of the condyle neck. The peak stress of 5 fixing screws was 9.707 5 MPa, which appeared on the 2# and 5# screws near the trailing edge of the mandibular ascending branch. The peak stress of both the prosthesis and the screw was smaller than its yield strength. The maximum pressure of the condyle prosthesis prepared by FDM and SLS was (3 814.7±442.6) N and (1 193.970±260.350) N, respectively. Compared with the SLS preparation, the FDM prepared prosthesis not only had higher compression strength but also better toughness. Conclusions The 3D printed personalized PEEK condyle prosthesis shows uniform stress distributions and good mechanical properties, which can provide the theoretical basis for PEEK as reconstruction material for repairing temporomandibular joint.

Single Exposure to Cocaine Impairs Reinforcement Learning by Potentiating the Activity of Neurons in the Direct Striatal Pathway in Mice / 神经科学通报·英文版

Plasticity in the glutamatergic synapses on striatal medium spiny neurons (MSNs) is not only essential for behavioral adaptation but also extremely vulnerable to drugs of abuse. Modulation on these synapses by even a single exposure to an addictive drug may interfere with the plasticity required by behavioral learning and thus produce impairment. In the present work, we found that the negative reinforcement learning, escaping mild foot-shocks by correct nose-poking, was impaired by a single in vivo exposure to 20 mg/kg cocaine 24 h before the learning in mice. Either a single exposure to cocaine or reinforcement learning potentiates the glutamatergic synapses on MSNs expressing the striatal dopamine 1 (D1) receptor (D1-MSNs). However, 24 h after the cocaine exposure, the potentiation required for reinforcement learning was disrupted. Specific manipulation of the activity of striatal D1-MSNs in D1-cre mice demonstrated that activation of these MSNs impaired reinforcement learning in normal D1-cre mice, but inhibition of these neurons reversed the reinforcement learning impairment induced by cocaine. The results suggest that cocaine potentiates the activity of direct pathway neurons in the dorsomedial striatum and this potentiation might disrupt the potentiation produced during and required for reinforcement learning.

Generation and characterization of recombinant classical swine fever virus C-strain expressing the cap protein of porcine circovirus type 2 / 生物工程学报

Classical swine fever (CSF), caused by classical swine fever virus (CSFV), is a devastating viral disease in swine, leading to significant economic losses to the pig husbandry. C-strain is one of the best modified live vaccines against CSF. The vaccine is highly safe and efficacious and can provide rapid and complete protection against essentially all genotypes of CSFV. Co-infections of pigs with CSFV and porcine circovirus type 2 (PCV2) occur frequently in the field, making it difficult to control the associated diseases. Here, a recombinant C-strain rHCLV-Cap expressing the Cap protein of PCV2 was constructed and evaluated in vitro and in vivo. The recombinant had comparable phenotypes to C-strain in cell cultures and rabbits. At ten days post-immunization, anti-E2, but not anti-Cap, antibodies were detected in the rabbits inoculated with the recombinant virus. Our study warrants further work to construct C-strain-based bivalent vaccines.

Strategies for producing high-yield viral vaccine antigens / 生物工程学报

Vaccination is an important strategy to prevent infectious diseases. However, low antigen yield of vaccine producing strains may lead to high cost of vaccines, low antigen production and vaccine failure. In recent years, many efforts have been made to improve the antigen yield of many vaccines. This mini-review summarizes various methods for increasing the antigen yield for vaccine production, including genetic modification of viruses, improvement of the adaptation of viruses to cells, and optimization of antigen expression systems and manufacturing procedures. Furthermore, we discuss the advantages and the problems of current strategies, as well as indicate the perspectives.

Application of micro-power system in the surgery of tooth extraction / 华西口腔医学杂志

Tooth extraction is a common operation in oral surgery. Traditional-extraction instruments, such as bone chisel, elevator, and bone hammer, lead to not only severe trauma but also unnecessary complications, and patients easily become nervous and apprehensive if tooth extraction is performed using these violent instruments. In recent years, with the develop- ment of minimally invasive concept and technology, various micro-power instruments have been used for tooth extraction. This innovative technology can reduce the iatrogenic trauma and complications of tooth extraction. Additionally, this technology can greatly decrease the patient's physical and mental pressure. The new equipment compensates for the deficiency of traditional tooth extraction equipment and facilitates the gradual replacement of the latter. Diverse micro-power systems have distinct strengths and weaknesses, so some auxiliary instruments are still needed during tooth extraction. This paper focuses on the various micro-power systems for tooth extraction and tries to compare the advantages and disadvantages of these systems. Selection and usage of auxiliary equipment are also introduced. Thus, this paper provides reference for the proper application of the micro-power systems in tooth extraction.

Effect of hepatopoietin Cn on liver stem cells / 军事医学

Objective To investigate the effect of hepatopoietin Cn(HPPCn) on liver stem cells.Methods In this study, WB-F344 cell line was used, and MTT and flow cytometry assay were conducted to determine cell proliferation and apoptosis.Transwell assay was used to test the migration of WB-F344 cells.A 2AAF-partial hepatectomy(PH) mouse model was used to observe the effect of HPPCn on liver stem cell proliferation in vivo.Results HPPCn enhanced WB-F344 cell proliferation and migration and activated the SphK1, Erk and Stat3 signal pathways.The analysis of the 2AAF-PH mouse model showed that oval cells in the experimental group far outnumbered those in control and the regeneration of the liver was improved post PH.Conclusion HPPCn can increase the liver stem cell proliferation and survival while promoting the regenenation of the liver by augmenting oval cell proliferation.

Expression of WWOX and C-JUN in keloid / 中华医学美学美容杂志

Objective To study the expression of WWOX and C-JUN in keloid and to approach their role and mechanism in the pathogenesis of keloid.Methods Immunohistochemical SP methods were used with computer pathological image analysis.Western blot and reverse transcription polymerase chain reaction (RT-RCR) were performed to detect the expression of WWOX and C-JUN in keloid and normal skin with statistical analysis.Results In keloid,the expression of WWOX protein was located in the cytoplasm of fibroblasts,and the expression of WWOX protein and its mRNA decreased,with significantly statistical difference (P＜0.05) compared to normal skin in the control group; the expression of C-JUN protein was located in the cell nucleus and cytoplasm of fibroblasts,with increased expression of C-JUN protein and its mRNA,with significantly statistical difference (P＜0.05) in comparison to normal skin in the control group.The expression of both was negative correlation (r=-0.626,P＜0.01).Conclusions Both WWOX with low expression and C-JUN with high expression are keloid-related genes,having significantly negative correlation between them,which may be one of the mechanisms for the keloid formation.It indicates that the WWOX protein may be an inhibitory factor to the expression of C-JUN protein,and the genes may play a major role in the pathogenesis of keloiod through fibroblasts.

In-vitro study of glycogen synthase kinase-3β on regulation of migration, invasion and epithelial-mesenchymal transition in pancreatic cancer cells / 中华普通外科杂志

Objective To explore the role of GSK-3β in migration,invasion,metastasis and epithelial-mesenchymal transition of pancreatic cancer in vitro.Methods Lentiviral interference was used to inhibit the expression of GSK-3β in pancreatic cancer cells.Western blotting was used to detect expression of GSK-3β phosphorylation molecules and epithelial-mesenchymal transition and invasion related molecule.Scratch test and transwell test were adopted to detect the effect of GSK-3β inhibition on cell migration and invasion in pancreatic cancer cells.Luciferase reporter gene test was used to detect the effect of GSK-3β inhibition on NF-κB binding activity.Results Inhibition of GSK-3β expression significantly restrain migration,invasion and epithelial-mesenchymal transformation.Migration inhibitory rate was 59.1％ ±6.4％ in ASPC-1 group and 55.9％ ± 7.3％ in PANC-1 group.GSK-3β inhibition affected the activity of NF-κB,the binding activity decreased to 24.8％ ± 3.1％ and 31.5％ ±5.4％,respectively (all P ＜ 0.05).Conclusions GSK-3β participates in the regulation of migration,invasion,and epithelialmesenchymal transition of pancreatic cancer.GSK-3β inhibition could surpress proliferation,invasion and epithelial-mesenchymal transformation,and NF-κB might be the key molecule in the regulation of pancreatic malignant behavior.

Management of inoperable advanced pancreatic head carcinoma without gastric outlet obstruction: an analysis of 441 patients / 中华普通外科杂志

Objective To explore the optimal management strategies for unresectable advanced pancreatic head carcinoma without preoperative gastric outlet obstruction(GOO).Methods Clinical data of 441 cases of advanced pancreatic head carcinoma without GOO undergoing surgery from Jan 2001 to Dec 2010 were analyzed retrospectively.Results Among the 441 cases of advanced pancreatic head carcinoma without GOO,101 patients received simple Roux-en-Y cholecystojejunostomy (group A),133 patients received simple Roux-en-Y choledochojejunostomy (group B),83 patients received Roux-en-Y cholecystojejunostomy combined gastrojejunostomy(group C) and the other 124 patients received Roux-en-Y choledochojejunostomy combined gastrojejunostomy (group D).The postoperative recurrent obstructive jaundice rates were 7.9％ and 6.0％ in group A and C,respectively; the postoperative de novo GOO rates were 8.9％ and 8.3％ in group A and B,respectively; there were no differences in median survivals among the four groups (F =1.933,P =0.123).Conclusions Choledochojejunostomy is effective for the reduction of recurrent obstructive jaundice for advanced pancreatic head carcinoma patients without GOO,combined prophylactic gastrojejunostomy during surgical biliary drainage could decrease the rate of postoperative GO0.Cholecystojejunostomy could be only applied for patients with poor health or when choledochojejunostomy is a taboo.

Effects of insulin on proliferation and invasion of human pancreatic cancer PANC1 cells / 中华胰腺病杂志

ObjectiveTo investigate the effects of insulin on the proliferation and invasion of human pancreatic cancer cells PANC1,and on its HIF-1α,VEGF expression.MethodsPANC1 was pretreated with insulin of different concentrations (0.1,1,10,100 nmol/L).The proliferation of PANC1 was tested by MTTmethod,and transwell assay was used to test the invasion ability of PANC1.HIF-1α,VEGF and PCNA protein expression was assessed by Western blots,and HIF-1α,VEGF mRNA was detected by real-time PCR.Results Insulin could increase the proliferation of PANC1 in a dose-dependent manner (p ＜0.05 ),and increase the expression of HIF-1α,VEGF protein.After 100 nmol/L insulin treatment for4 d,the PCNA protein expression in the insulin group was significantly higher than that in the control group (1.196 ±0.014 vs 1.157 ±0.013,P ＜ 0.05).The cancer cells passed through the chamber in insulin group were much more than that in the control group ( 141.0 ± 2.1 vs 89.0 ± 1.4,P ＜0.05 ).The expression of HIF-1α protein was significantly increased (1.139 ±0.020 vs 0.598 ±0.013,P ＜0.05),while there was no significant change of HIF-1αmRNA expression.Both the expression of VEGF protein and mRNA were significantly increased (1.011 ± 0.023 vs 0.627 ± 0.013 0.970 ± 0.016 vs 0.350 ± 0.01 3,P ＜ 0.05 ).Conclusions High insulin microenvironment could enhance the proliferation and invasion of PANC1 cells by up-regulating the expression of HIF-1α and VEGF.

Research advances on chemotherapy-induced amenorrhea of breast cancer / 国际肿瘤学杂志

The majority of women diagnosed with early-stage breast-cancer have an excellent long-term prognosis, but many still suffer from worsened life quality and infertility caused by chemotherapy-induced amenorrhea(CIA). The risk of CIA varies by patient age, but is not significantly influenced by chemotherapeutic regimens. CIA will improve disease-free survival and overall survival for patients with hormonal receptor positive tumors. For low-risk patients and patients with the intention of maintaining fertility, proper treatments need to be chosen to preserve their reproductive function.

Foxm1 research progress in cell cycle and tumor / 国际肿瘤学杂志

Forkhead Box m1 ( Foxm1) is a component of the Fox transcription factor family. It is only detected in proliferating cells, but disappears when cells enter into their terminal differentiation phase. Foxml is closely related to cellular growth mainly through inhibiting cyclin-dependent kinase(cdk) inhibitors to influence cell proliferation. It also participates in growth hormone mediated cell multiplication. The overexpression of Foxml has been observed in many tumor cell lines and malignant tumors, indicating that Foxml might be an essential proto-oncogene in carcinoaenesis. Upregulation of Foxml is sufficient to induce genomic instability due to loss of heterozygosity and variation of copy numbers. Foxml-induced genomic instability was significantly enhanced and accumulated with increasing cell passages. Foxml might become a new potential target for the treatment human cancer based on future investigations.

Influence of anthracycline-based chemotherapy on menstruation of patients with breast cancer / 肿瘤研究与临床

Objective To study the influence of aging and chemotherapeutic drugs of breast cancer patients on chemotherapy-induced amenorrhea (CIA) and to guide the further selection of drugs for chemotherapy.Methods We prospectively studied the CIA of the premenopausal breast cancer patients and compared the difference in CIA between the patients who were at different aging periods or received different chemotherapeutics. Results 137 patients were followed up.The occurrence rate of CIA and long-term chemotherapy-induced amenorrhea(LCIA)were 73.72%(101/137)and 43.80%(60/137)respectively.The rate of CIA and LCIA was significandy higher in older women(＞40 years)than young women(≤40 years,X2=25.32,18.42,P＜0.05).The recovery rate of CIA in young women was 61.90%(13/21)which was significantly higher than the older women[35.00%(28/80);X2=4.99,P=0.025].The difference in the rate of LCIA was statistically significant between the older women (＞40 years)who received different anthracyclinebased chemotherapy(X2=6.92,P=0.031).Conclusion Age is an important factor for the CIA.Chemotherapy has less influence on the menstruation of younger women(≤40) and most amenorrhea is reversible.For older women,the rate of LCIA is different in patients who receive imported epirubicin,domestic epirubicin or pirarubicin.

Advances in predictive factors of neoadjuvant chemotherapy in breast cancer / 国际肿瘤学杂志

Predictive factors of neoadjuvant chemotherapy play an important role in selecting sensitive chemotherapy regimen and avoiding unsuitable regimen for breast cancer patients. At present, estrogen receptor (ER), progestin receptor (PR) and HER-2 status are the main predictive factors. Other factors such as Ki-67 also seem to be promising for optimizing neoadjuvant chemotherapy.

Expression of acetohydroxyacid synthase isozyme genes ilvBN, ilvGM, ilvIH and their resistance to AHAS-inhibitor herbicides / 生物工程学报

Acetohydroxyacid synthase (AHAS) catalyses the first reaction in the pathway for synthesis of the branched-chain amino acids. AHAS is the target for sulfonylurea, imidazolinone and other AHAS-inhibitor herbicides. Herbicides-resistant AHAS genes have potential application in plant transgenetic engineering and development of new generation herbicide. The AHAS isozyme genes ilvBN, ilvGM and ilvIH were cloned from metsulfuron-methyl resistant strain Klebsiella sp. HR11 and metsulfuron-methyl sensitive strain Klebsiella pneumoniae MGH 78578. Homologous sequences comparison indicated that the differences in AHAS isozyme genes at amino acid levels between strain HR11 and strain MGH 78578 were mainly on the large subunits of ilvBN and ilvGM. The three AHAS isozyme genes from HR11 and MGH 78578 were ligated into the expression vector pET29a(+) and expressed in Escherichia coli BL21, respectively. The results of enzyme inhibition assay showed that only ilvBN and ilvGM from strain HR11 showed strong resistance to AHAS-inhibitor herbicides, while ilvIH from strain HR11 and ilvBN, ilvGM and ilvIH from strain MGH78578 were sensitive to AHAS-inhibitor herbicides.

Study on the purification and binding activity of the sodium channel / 中国药理学通报

Aim To apply sodium channels isolated and purified from rat brain and rat skelatal muscle sarcolemma to the study conotoxin.Methods Crude isolations of sodium channels were purified by 3 kinds of chromatography.The interaction between the sodium channels and conus betulinus was studied by the ligand binding experiment.Result The sequential chromatography resulted in 370-fold purification from rat brain and 2436-fold purification from rat skeletal muscle.Average specific binding active sites of purified sodium channels increased to 321 nmol?g-1 for rat brain and 268 nmol?g-1 for rat skeletal muscle respectively;Studying the interaction between venom from conus betulinus and the purified sodium channels indicated the fraction Ⅴ8 showed the highest affinity for the binding sites of the purified sodium channels.Conclusion Rat brain sodium channel and rat skeletal muscle sodium channel were purified to high purity;the fraction Ⅴ8 has the similar effect to that of the traditional ?-conotoxin.