2. Bionic mechanical design and 3D printing of novel porous Ti6Al4V implants for biomedical applications
Journal of Zhejiang University. Science. B 2019;20(8):647-659
In maxillofacial surgery, there is a significant need for the design and fabrication of porous scaffolds with customizable bionic structures and mechanical properties suitable for bone tissue engineering. In this paper, we characterize the porous Ti6Al4V implant, which is one of the most promising and attractive biomedical applications due to the similarity of its modulus to human bones. We describe the mechanical properties of this implant, which we suggest is capable of providing important biological functions for bone tissue regeneration. We characterize a novel bionic design and fabrication process for porous implants. A design concept of “reducing dimensions and designing layer by layer” was used to construct layered slice and rod-connected mesh structure (LSRCMS) implants. Porous LSRCMS implants with different parameters and porosities were fabricated by selective laser melting (SLM). Printed samples were evaluated by microstructure characterization, specific mechanical properties were analyzed by mechanical tests, and finite element analysis was used to digitally calculate the stress characteristics of the LSRCMS under loading forces. Our results show that the samples fabricated by SLM had good structure printing quality with reasonable pore sizes. The porosity, pore size, and strut thickness of manufactured samples ranged from (60.95± 0.27)% to (81.23±0.32)%, (480±28) to (685±31) µm, and (263±28) to (265±28) µm, respectively. The compression results show that the Young’s modulus and the yield strength ranged from (2.23±0.03) to (6.36±0.06) GPa and (21.36±0.42) to (122.85±3.85) MPa, respectively. We also show that the Young’s modulus and yield strength of the LSRCMS samples can be predicted by the Gibson-Ashby model. Further, we prove the structural stability of our novel design by finite element analysis. Our results illustrate that our novel SLM-fabricated porous Ti6Al4V scaffolds based on an LSRCMS are a promising material for bone implants, and are potentially applicable to the field of bone defect repair.
5.Killing effect of dendritic cell vaccine transfected by recombinant adeno-associated virus with hAFP gene fragment on hepatocellular carcinoma cells in vitro.
Jian-hai SUN ; Yan-ling MA ; Ming-e PENG ; Ai-gui BIE ; Li LI ; Li LIU
Chinese Journal of Oncology 2010;32(5):334-338
OBJECTIVEDendritic cell vaccines are one of the important active immunotherapies for neoplasms. The aim of this study was to observe the killing effect of specific cytotoxic T lymphocytes (CTL) on liver carcinoma HepG2 and SMMC-7721 cells in vitro. The CTL was induced by human peripheral blood mononuclear cells-originated dendritic cells (DC) transfected by recombinant adeno-associated virus (rAAV) with hAFP gene fragment (137-145).
METHODSImmature DCs were generated from peripheral blood mononuclear cells of healthy volunteers and then transfected by rAAV with AFP gene fragment. The CTL was thereafter induced. The activities of DC and CTL were measured and the killing effect of the CTL on HepG2 cells was detected using M1Tr assay.
RESULTSThe mature DC, transfected or not, highly expressed CD40, CD86 and IL-12. IFN-gamma was highly expressed in the CTL. The DC-induced CTL could effectively recognize and destroy the HepG2 and SMMC-7721 cells.
CONCLUSIONDC transfected by rAAV can stimulate the proliferation and differentiation of lymphocytes and also induce the proliferation of CTL, and their own phenotypes are not significantly altered. The DC vaccine can be effectively used as an adjuvant immunotherapy for patients with hepatocellular carcinoma.
B7-2 Antigen ; metabolism ; CD40 Antigens ; metabolism ; Cancer Vaccines ; immunology ; Carcinoma, Hepatocellular ; pathology ; Cell Differentiation ; Cell Line, Tumor ; Cell Proliferation ; Cytotoxicity, Immunologic ; Dendritic Cells ; cytology ; immunology ; metabolism ; Dependovirus ; genetics ; Hep G2 Cells ; Humans ; Interferon-gamma ; metabolism ; Interleukin-12 ; metabolism ; Liver Neoplasms ; pathology ; Peptide Fragments ; genetics ; T-Lymphocytes, Cytotoxic ; immunology ; metabolism ; pathology ; Transfection ; alpha-Fetoproteins ; genetics
6.Low expression of SLC22A1 is associated with a poor prognosis of hepatocellular carcinoma: analysis of 303 patients.
Shu-Tong WANG ; Shun-Li SHEN ; Yun-Peng HUA ; Bin CHEN ; Ming KUANG ; Shao-Qiang LI ; Qiang HE ; Bao-Gang PENG
Journal of Southern Medical University 2015;35(10):1417-1421
OBJECTIVETo evaluate the association between SLC22A1 expression and the outcomes of hepatocellular carcinoma (HCC) patients.
METHODSA tissue microarray of 303 HCC and matched adjacent noncancerous liver tissues (ANLTs) were constructed. The expression of SLC22A1 was tested by immunohistochemistry (IHC) and scored by two pathologists according to a 12-score scale (a score>6 was defined as high expression, and a score≤6 as low expression). The correlation of SLC22A1 expression with the clinicopathological features and the patients' outcome was analyzed.
RESULTSAll the ANLTs had a IHC score of 12, as compared to only 29 (9.6%) of the HCC tissues. The patients were divided into 2 groups based on the IHC scores: 59% (180/303) in low expression group and 41% (123/303) in high expression group. The disease-free survival (DFS) rates and overall survival (OS) rates were significantly lower in low SLC22A1 expression group than in the high expression group. The 1-, 3-, and 5-year DFS rates were 43%, 31% and 27% in the low expression group, and were 58%, 47% and 43% in the high expression group, respectively. The 1-, 3-, and 5-year OS rates were 66%, 38% and 32% in low expression group, and were 80%, 57% and 50% in the high expression group, respectively. A low expression of SLC22A1 was positively correlated with the tumor diameter, BCLC stage, tumor differentiation, and AFP levels (P<0.05), and was an independent predictor of poor overall survival (HR=1.454; 95% CI, 1.050-2.013).
CONCLUSIONSDown-regulation of SLC22A1 is a malignant feature and a potential prognostic marker of HCC.
Carcinoma, Hepatocellular ; diagnosis ; metabolism ; Disease-Free Survival ; Down-Regulation ; Humans ; Immunohistochemistry ; Liver Neoplasms ; diagnosis ; metabolism ; Organic Cation Transporter 1 ; metabolism ; Prognosis ; Survival Rate ; Tissue Array Analysis
7.Larvicidal activity of recombinant Escherichia coli expressing scorpion neurotoxin AaIT or B.t.i toxin Cyt2Ba against mosquito larvae and formulations for enhancing the effects.
Sheng-Qun DENG ; Ming-Zhi DENG ; Jia-Ting CHEN ; Li-Lan ZHENG ; Hong-Juan PENG
Journal of Southern Medical University 2017;37(6):750-754
OBJECTIVETo assess the larvicidal effects of recombinant Escherichia coli expressing scorpion neurotoxin AaIT or Bacillus thuringiensis subsp israelensis (B.t.i) toxin Cyt2Ba against the second instar larvae of Culex pipiensquinquefasciatus and Aedes albopictus and compare different formulations for their larvicidal effects.
METHODSThe AaIT- or Cyt2Ba-coding sequences were cloned into pET28a(+) and the recombinant plasmids were transformed into E. coli BL21(DE3). After induction with IPTG, the recombinant proteins expressed by the recombinant E. coli were detected and identified by SDS-PAGE and Western blotting, respectively. The larvicidal activity of the bacterial suspension was tested at different concentrations against mosquitoes. The effective engineered bacteria were prepared into dry powder with different formulations, and their larvicidal activity was tested.
RESULTSAaIT and Cyt2Ba proteins were successfully expressed in E. coli. The recombinant AaIT protein showed no virulence to the mosquito larvae. The suspension of the recombinant E. coli expressing Cyt2Ba protein exhibited a stronger killing effect on Aedes albopictus larvae than on Culex pipiens quinquefasciatus larvae at 48 h (P<0.001) with LCof 3.00×10cells/mL and 1.25×10cells/mL, respectively. The dry powder of the engineered bacteria formulated with yeast extract, wheat flour or white pepper powder at the mass ratio of 1:1 showed the strongest killing effect on mosquito larvae (P=0.044), and the formulation with white pepper powder produced a stronger killing effect than formulations with yeast extract or wheat flour (P=0.002).
CONCLUSIONThe B.t.i Cyt2Ba protein expressed in E. coli BL21(DE3) shows a good larvicidal activity against mosquitoes, and appropriate formulations of the engineered bacteria can enhance its efficiency in mosquito control.
8.Long-term prognosis of patients with acute non-ST-segment elevation myocardial infarction undergoing different treatment strategies.
Bo ZHANG ; Da-Peng SHEN ; Xu-Chen ZHOU ; Jun LIU ; Rong-Chong HUANG ; Yan-E WANG ; Ai-Ming CHEN ; Ye-Ran ZHU ; Hao ZHU
Chinese Medical Journal 2015;128(8):1026-1031
BACKGROUNDIn cardiology, it is controversial whether different therapy strategies influence prognosis after acute coronary syndrome. We examined and compared the long-term outcomes of invasive and conservative strategies in patients with non-ST-segment elevation myocardial infarction (NSTEMI) and characterized the patients selected for an invasive approach.
METHODSA total of 976 patients with acute NSTEMI were collected from December 2006 to October 2012 in the First Affiliated Hospital of Dalian Medical University Hospital. They are divided into conservative strategy (586 patients) and invasive strategy (390 patients) group. Unified follow-up questionnaire was performed by telephone contact (cut-off date was November, 2013). The long-term clinical events were analyzed and related to the different treatment strategies.
RESULTSThe median follow-up time was 29 months. Mortality was 28.7% (n = 168) in the conservative group and 2.1% (n = 8) in the invasive management at long-term clinical follow-up. The secondary endpoint (the composite endpoint) was 59.0% (n = 346) in the conservative group and 30.3% (n = 118) in the invasive management. Multivariate analysis showed that patients in the conservative group had higher all-cause mortality rates than those who had the invasive management (adjusted risk ratio [RR] = 7.795; 95% confidence interval [CI]: 3.796-16.006, P < 0.001), and the similar result was also seen in the secondary endpoint (adjusted RR = 2.102; 95% CI: 1.694-2.610, P < 0.001). In the subgroup analysis according to each Thrombolysis in Myocardial Infarction risk score (TRS), log-rank analysis showed lower mortality and secondary endpoint rates in the invasive group with the intermediate and high-risk patients (TRS 3-7).
CONCLUSIONSAn invasive strategy could improve long-term outcomes for NSTEMI patients, especially for intermediate and high-risk ones (TRS 3-7).
Acute Coronary Syndrome ; mortality ; pathology ; therapy ; Aged ; Female ; Humans ; Male ; Middle Aged ; Myocardial Infarction ; mortality ; pathology ; therapy ; Prognosis ; Retrospective Studies
9.Effects of insulin like growth factor-1 on cell viability and tissue factor in vascular endothelial cells.
Qi-Lin MA ; Tian-Lun YANG ; Ming SUN ; Yuan-Jian LI ; Can-E TANG ; Zhen-Yu PENG ; Shi-Lin HE ; Fang-Ping CHEN
Chinese Journal of Hematology 2007;28(9):605-608
OBJECTIVETo study the effects of insulin like growth factor-1 (IGF-1) on cell viability and tissue factor (TF) in angiotensin II (Ang II) induced vascular endothelial cells and to investigate its mechanisms.
METHODS10(-6) mol/L Ang II was added to human vascular endothelial cells (HUVECs) culture media alone or 30 min after pretreatment with IGF-1 (0.1 microg/ml , 0.5 microg/ml, 2.5 microg/ml). Cell viability and AngII type 1 receptor (AT1-R) mRNA were evaluated after 24 h incubation with AngII. At the optimum concentration of IGF-1 affecting cell viability, the time dependent manner for 12 - 48 h incubation with Ang II was evaluated. TF, NOS and NO were investigated after 24 h incubation with Ang II. In addition, NO synthase inhibitor Nomega-nitro-1-arginine methylester(L-NAME) was added 30 min before addition of IGF-1 and Ang II, and cell viability, TF, AT1-R mRNA, NOS and NO were evaluated after 24 h incubation.
RESULTS(1) Ang II induced a decrease in cell vitality, an upregulation of AT1-R mRNA, an increase in TF, and a decrease in the activity of NOS and content of NO. (2) Pretreatment with IGF-1 significantly inhibited the decreased cell viability and upregulation of AT1-R mRNA. IGF-1 at 0.5 microg/ml showed the most obvious effects. This effect of cell viability recovery was in a time dependent manner during 12 -48 h. (3) IGF-1 also inhibited the increased content of TF, the decreased activity of NOS and the decreased content of NO. (4) The beneficial effects of IGF-1 on cultured endothelial cells were completely abolished by L-NAME.
CONCLUSIONIGF-1 pretreatment could enhance the ang II injured cell viability and anti-thrombosis capacity, and the protective effects may be related to activation of NOS-NO signaling pathway which inhibited AT1-R.
Angiotensin II ; pharmacology ; Cell Survival ; drug effects ; Cells, Cultured ; Endothelial Cells ; drug effects ; metabolism ; physiology ; Humans ; Insulin-Like Growth Factor I ; pharmacology ; Nitric Oxide ; metabolism ; Nitric Oxide Synthase ; metabolism ; Receptor, Angiotensin, Type 1 ; genetics ; metabolism ; Thromboplastin ; metabolism
10.Antitumor activity of lycorine in renal cell carcinoma ACHN cell line and its mechanism.
Yi-Qiang HUANG ; Yi-Ming ZHANG ; Zhong JIN ; Xie-Zhao LI ; Chong-Shan WANG ; Kai XU ; Peng HUANG ; Chun-Xiao LIU
Journal of Southern Medical University 2016;36(6):857-862
OBJECTIVETo investigate the antitumor effect of lycorine on renal cell carcinoma ACHN cells and explore the possible mechanism.
METHODSWe used flow cytometry to examine the effect of lycorine on ACHN cell cycle and apoptosis. The cell proliferation, migration and invasion were assessed with MTS assay, wound healing assay, and Transwell assay, respectively. Colony forming assay was performed, and the mRNA and protein levels of Bax, Bcl-2, survivin, caspase-3, cyclin D1 and CDK4 were measured with qRT-PCR and Western blotting.
RESULTSLycorine obviously inhibited the proliferation of ACHN cells with an IC(50) of 24.34 µmol/L. Lycorine also induced apoptosis of ACHN cells, caused cell cycle arrest at G(0)/G(1) phase, and suppressed the colony forming ability of the cells in a dose-dependent manner. The migration and invasion of ACHN cells were significantly inhibited by 5 µmol/L lycorine. Lycorine up-regulated the mRNA levels of CDK4, Bax, caspase-3 while down-regulated the levels of survivin, Bcl-2 and Cyclin D1; the protein levels of CDK4 and Bax were increased and cyclin D1, Bcl-2 and surviving expressions were decreased, but caspase-3 expression showed no significant changes following the treatment.
CONCLUSIONLycorine has obvious antitumor effect against ACHN cells, suggesting its value as a new therapeutic agent for renal cell carcinoma.
Amaryllidaceae Alkaloids ; pharmacology ; Antineoplastic Agents, Phytogenic ; pharmacology ; Apoptosis ; Carcinoma, Renal Cell ; pathology ; Caspase 3 ; metabolism ; Cell Cycle Checkpoints ; Cell Line, Tumor ; drug effects ; Cell Proliferation ; Cyclin D1 ; metabolism ; Cyclin-Dependent Kinase 4 ; metabolism ; Humans ; Inhibitor of Apoptosis Proteins ; metabolism ; Phenanthridines ; pharmacology ; Proto-Oncogene Proteins c-bcl-2 ; metabolism ; bcl-2-Associated X Protein ; metabolism