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BACKGROUND: Adipose mesenchymal stem cells are currently recognized as excellent seed cells for tissue engineering cartilage. Gene transfection technology can effectively induce them to differentiate into cartilage. The bioreactor is used to simulate the mechanical environment in vivo. It is a new idea for the majority of scholars to explore the construction of tissue engineering cartilage in vitro. OBJECTIVE: To investigate the effects of cyclic dynamic compressive stress combined with insulin-like growth factor-1 gene transfection on the proliferation and elastic modulus of rabbit adipose mesenchymal stem cells implanted in chitosan/gelatin scaffold. METHODS: Rabbit adipose mesenchymal stem cells were transfected with pcDNA3.1-IGF-1 gene mediated by liposome. The stable transfected cell lines were screened by G418. The adipose mesenchymal stem cells transfected with or without insulin-like growth factor-1 gene were inoculated in chitosan/ gelatin scaffold at the density of 5×1010 L-1 for 2 days, and cultured under dynamic pressure (2% at 1 Hz, 4 hours per day) or static culture conditions for 7 days, respectively. The morphological changes of the cell/scaffold complex were observed by scanning electron microscope, Masson trichrome staining and alcian blue staining. The cell proliferation curve was drawn by MTT assay. The cell proliferation efficiency and distribution were evaluated by CM-Dil fluorescence-labeling method, and the content of total glycosaminoglycan was quantitatively determined by DMMB. The differences of type II collagen among different groups were compared with real time PCR. Compressive mechanical properties of the cell/scaffold constructs were assessed using a BioDynamic™ mechanical tester, and the corresponding elastic modulus was calculated. RESULTS AND CONCLUSION: Dynamic pressure combined with insulin-like growth factor-1 transfection could significantly improve the cell proliferation ability of the cell/scaffold complex; the cell distribution was more uniform; glycosaminoglycan and collagen secretion in the cartilage-specific extracellular matrix were increased; the expression levels of type II collagen were up-regulated; and the mechanical properties were significantly improved. The cell proliferation and elastic modulus of insulin-like growth factor-1 group were better than those of single pressure group, but the distribution of cells in scaffolds was more uniform under dynamic pressure. The results indicate that both dynamic pressure and insulin-like growth factor-1 gene transfection can significantly improve the proliferation and mechanical properties of rabbit adipose mesenchymal stem cells; the two have synergistic effect.
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OBJECTIVE: Imaging diagnosis of cervical lymphadenopathy has conventionally used ultrasonography. Shear wave elastography (SWE) is a recent ultrasound technological advancement that has shown promise in the important medical problem of differentiating between benign and malignant cervical lymph nodes based on quantitative measurements of elasticity modulus. However, widely varying elasticity modulus metrics and regions-of-interest (ROIs) were used in existing studies, leading to inconsistent findings and results that are hard to compare with each other. METHODS: Using a large dataset of 264 cervical lymph nodes from 200 patients, we designed a study comparing three elasticity modulus metrics (Emax, Emean, and standard deviation-SD) with three different ROIs to evaluate the effect of such selections. The metric values were compared between the benign and malignant node groups. The different ROI and metric selections were also compared through receiver operating characteristics curve analysis. RESULTS: For all ROIs, all metric values were significantly different between the two groups, indicting their diagnostic potential. This was confirmed by the ≥0.80 area under the curve (AUC) values achieved with these metrics. Different ROIs had no effect on Emax, whereas all ROIs achieved high performance at 0.88 AUC. For Emean, the smallest ROI focusing on the area of the highest elasticity achieved the best diagnostic performance. In contrast, the larger ROIs achieved higher performances for SD. CONCLUSIONS: This study illustrated the effect of elasticity modulus and ROI selection on the diagnostic performance of SWE on cervical lymphadenopathy. These new findings help guide relevant future studies and clinical applications of this important quantitative imaging modality.
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Humans , Breast Neoplasms , Elasticity Imaging Techniques , Reproducibility of Results , Ultrasonography , Sensitivity and Specificity , Diagnosis, Differential , Elastic Modulus , Lymph Nodes/diagnostic imaging , Neck/diagnostic imagingABSTRACT
Objective To investigate the correlativity between elasticity modulus and pathological severity in chronic pancreatitis (CP).Methods Twenty-one pigs were divided randomly into experimental group (n=18) and control group (n=3) using random number method.The main pancreatic duct (MPD) was incompletely ligated to establish the CP model.In control group, MPD was not ligated.The animals were killed in batches at 4th, 8th and 12th week after surgery.The pancreatic tissue was taken for elasticity modulus test and pathological examination, and the pigs were classified into control, mild, moderate and severe groups based on the severity of fibrosis.Cell density, fat infiltration and extracellular edema were observed and classified into mild and severe.The difference of elasticity modulus among different groups were compared by Variance analysis, the correlation between pancreatic fibrosis and elastic modulus was analyzed with Spearman correlation analysis, and ROC curve was used to evaluate its efficacy of diagnosing CP.Results Sixteen CP models were established successfully expected for 2 deaths (mild, n=7;moderate, n=2 and severe, n=7).All of the control group (n=3) showed normal pancreas.The elasticity modulus of control, mild and moderate to severe group were 0.4268±0.0566, 0.3203±0.0518 and 0.2235±0.0685, respectively.The difference between the groups was statistically significant (F=13.658,P0.05).Conclusions The elasticity modulus can be used to detect the pathological changes of CP, and evaluate the CP pathologic grades.
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Objective To explore the influence of different lengths and contents of glass-fiber post on the fracture resistance of teeth, and to investigate the optimal length and content of glass-fiber post used for restorative treatment. Meth-ods Forty-two intact single canal mandibular premolars were collected from orthodontic patients and were divided into three experimental groups (A, B and C). All the teeth were endodontically treated after cut off the crowns from the 2 mm above cemento-enamel junction. The post lengths were10 mm in A group, 8 mm in B group, and 6 mm in C group.There were two subgroups for each experimental group (A1, A2, B1, B2, C1, C2 ), 7 teeth for each subgroup.The 42%glass fiber post was used in A1, B1 and C1 groups. The 75%glass fiber post was used in A2, B2 and C2 groups. All of groups were restored with resin cores and metal crowns. The fracture resistance was measured with universal testing machine and recorded the root frac-ture pressure data and the mode of all the teeth. Results The fracture resistance was significantly higher in group A than that of group B and group C (P<0.05), and the fracture resistance was significantly higher in group B than that of group C (P<0.05). The fracture resistance was significantly higher for 75%glass fiber post than that of 42%glass fiber post (P<0.05). Conclusion Within a certain range, the longer the length of glass fiber post, the greater the tooth fracture resistance. The fracture resistance of fiber content is better for 75%glass fiber post than that of 42%glass fiber post.