Objective To investigate variation in the carotid bifurcation geometry of adults of different age by MR angiography images combining image post-processing technique. Methods Images of the carotid bifurcations of 27 young adults (≤40 years old) and 30 older subjects ( >40 years old) were acquired via contrast-enhanced MR angiography. Three dimensional (3D) geometries of the bifurcations were reconstructed and geometric parameters were measured by post-processing technique. Results The geometric parameters of the young versus older groups were as follows: bifurcation angle (70.268°± 16.050° versus 58.857°±13.294°), ICA angle (36.893°±11.837° versus 30.275°± 9.533°), ICA planarity (6.453°±5.009° versus 6.263°±4.250°),CCA tortuosity (0.023°0.011 versus 0.014± 0.005), ICA tortuosity (0.070±0.042 versus 0.046±0.022), ICA/CCA diameter ratio (0.693± 0.132 versus 0.728±0.106), ECA/CCA diameter ratio (0.750±0.123 versus 0.809±0.122), ECA/ ICA diameter ratio (1.103±0.201 versus 1.127±0.195), bifurcation area ratio (1.057±0.281 versus 1.291±0.252). There was significant statistical difference between young group and older group in bifurcation angle, ICA angle, CCA tortuosity, ICA tortuosity, ECA/CCA and bifurcation area ratio (F= 17.16,11.74,23.02,13.38,6.54,22.80,respectively, P<0.05). Conclusions MR angiography images combined with image post-processing technique can reconstruct 3D carotid bifurcation geometry and measure the geometric parameters of carotid bifurcation in vivo individually. It provides a new and convenient method to investigate the relationship of vascular geometry and flow condition with atherosclerotic pathological changes.

OBJECTIVE: To evaluate the effect of microwave polymerization and water-bath heat polymerization on accuracy and flexural strength of denture base resin. METHODS: Ten maxillary complete dentures were prepared and divided into microwave polymerization and water-bath heat polymerization groups according to random number table, with 5 dentures in each group. In the microwave polymerization group, the dentures were heated for 9 minutes with 40% firepower, natural cooled, the pressure of flasking at 4.5 kg/mm~2. In the water-bath heat polymerization group, the temperature increased from room to 70℃, sustained for 1.5 hours, then rise to 100℃ for 0.5 hour. The dentures were maintained at 25℃ thermostatic water bath for a week. The denture base, as well as standard cast was cut down at posterior border of the second molar. Dimensional accuracy between the posterior border of upper complete denture and standardized cast at five different positions was measured by digital microscope. Specimens with 64 mm× 10 mm×2.5 mm were made for measuring flexural strength.RESULTS: ①The posterior border gaps between the upper complete denture and standardized cast was (141±78) urn and (147±74) μm cured by microwave polymerization and water-bath heat polymerization, which has no statistical difference. The flexural strength of denture base resin cured by the microwave polymerization and water-bath heat polymerization was (81.60±14.04) MPa and (84.24±17.65) MPa, and there was no statistical difference (P > 0.05). CONCLUSION: There is no significantly difference in the accuracy and flexural strength cured by microwave polymerization and by water-bath heat polymerization, but the microwave polymerization takes shorter time than that by water-bath heat polymerization.

Objective To evaluate the significance of dilated intercellular space (DIS) of squamous epithelium in lower-esophagus which was measured at light microscopy (LM) in the diagnosis of gastroesophageal reflux disease (GERD). Methods This study was divided into two parts. The first part consists of 133 GERD patients with typical symptoms, including 75 erosive esophagitis (EE) and 58 non-erosive reflux disease (NERD);the second part consists of 25 healthy volunteers as control; ambulatory 24-hr esophageal pH monitoring, endoscopy and biopsies which were taken in lower esophagus were performed in all individuals. NERD patients with negative ambulatory 24-hr esophageal pH monitoring were undertaken PPI test. We selected 43 individuals randomly (4 control, 11 NERD and 28 EE) to measure the intercellular space diameter with LM and transmission electronic microscopy (TEM) simultaneously. All the samples were observed at immersion objective, taken pictures and make the scale at the same time; all the pictures were measured by the computer-assisted morphometry and in the samples for one ease should be measured 100 points and then calculate the mean intercellular space diameter, while the TEM has the same procedures. Results A total of 158 individuals (90 male, 68 female) were enrolled in this study. The mean intercellular space diameter with LM of the controls, the NERD and the EE patients were (0.61±0.10)μm, (1.12±0.61)μm and (1.30±0.19) μm, respectively, with significant differences between the control and NERD group, the control and EE group, the EE and NERD group (P <0.05); the mean intercellular space diameter with LM of EE subgroup of LA-A, LA-B, LA-C, LA-D were (1.31±0. 23)μm, (1.27±0.17)μm, (1.31±0.14)μm, (1.33±0.11)μm, respectively, without significant differences among every two subgroups (P > 0.05);NERD patients with positive and negative 24-hr ambulatory pH monitoring were 40 and 17 cases, and the mean intercellular space diameter with LM were (1.12±0.16) μm, (1.11±0.31) μm, respectively, without significant differences between them (P >0.05) ;the cut-off value of mean intercellular space diameter with LM was 0. 85 μm, if combination the clinical GERD symptom, endoscopy and 24-hr ambulatory pH monitoring as gold standard, its sensitivity was 95.5% and specificity was 100%;the intercellular space diameter of the controls, the NERD patients and the EE patients with TEM were (0. 30±0.14)μm, (1.33±0.28)μm, (1.40±0. 22)μm, respectively,with significant differences between the control and NERD group, the control and EE group (P < 0.05). It was significant correlation in intercellular space diameter between LM and TEM (r=0.737, P=0.000).Conclusions The intercellular space diameter of squamous epithelium in lower esophagus of GERD patients can make quantitative study with LM. It is significant correlation with TEM. DIS with LM is one of sensitive, specific and objective marker of GERD.

Objective To observe the changes of the intercellular spaces of squamous epithelium of lower esophagus in gastroesophageal reflux disease(GERD).Methods Eleven outpatients with GERD symptoms more than 3 months [6 with nonerosive reflex disease(NERD)and 5 with erosive esophagitis(EE)]and 5 healthy volunteers were recruited.All of them underwent endoscopy and 24-hr ambulatory pH monitoring.Biopsies were taken in lower esophagus(2 cm above Z-line)for electron microscope examination.Results Intercellular spaces of esophageal epithelial cell in volun teers,NERD patients and EE patients were (0.374?0.073)?m,(1.308?0.079)?m and (1.332?0.144)?m respectively,with significant differences between the control group and the NERD or EE group.There was no difference between NERD group and EE group.Conclusions Dilated intercellular spaces were seen in both NERD and EE cases,which was significantly different from the control cases.

Objective To investigate the visualization and quantitation of hemodynamic variables at carotid artery bifurcation in vivo by combining computational fluid dynamics(CFD)and vascular imaging. Methods A healthy volunteer underwent CT angiography of left carotid artery by SIEMENS multi-slice CT. Parameters of hemodynamics at this carotid bifurcation were calculated and visualized by combining vascular imaging post-processing and CFD.Results (1) The average range of flow velocity was 0.04～0.36 m/s. A region of high velocity was seen at medial wall of internal carotid artery (ICA) and medial wall of external carotid artery (ECA), respectively. The largest contiguous region of low velocity occurred at the carotid bulb. (2)The average range of absolute pressure, static pressure and dynamic pressure was 100 266.70～101 615.90 Pa, -1058.34～290.88 Pa, and 6.12～553.25 Pa, respectively. (3) The average range of wall shear stress (WSS) at the bifurcation was 0.59～5.35 Pa. There was a large region of low WSS at carotid bulb and posterior wall of ICA, with the lowest value of 0.25 Pa. Also there was a small region of low WSS at anterior and lateral wall of ECA.Conclusion CFD combined with vascular imaging can calculate and visualize the parameters of hemodynamics at carotid bifurcation in vivo individually. It is an interdisciplinary science of computer, radiology and hemodynamics and provides a new method to investigate the relationship of vascular geometry and flow condition with atherosclerotic pathological changes.

Objective To investigate flow patterns at carotid bifurcation in vivo by combining computational fluid dynamics(CFD)and MR angiography imaging.Methods Seven subjects underwent contrast-enhanced MR angiography of carotid artery in Siemens 3.0 T MR.Flow patterns of the carotid artery bifurcation were calculated and visualized by combining MR vascular imaging post-processing and CFD. Results The flow patterns of the carotid bifurcations in 7 subjects were varied with different phases of a cardiac cycle.The turbulent flow and back flow occurred at bifurcation and proximal of internal carotid artery (ICA)and external carotid artery(ECA),their occurrence and conformation were varied with different phase of a cardiac cycle.The turbulent flow and back flow faded out quickly when the blood flow to the distal of ICA and ECA.Conclusion CFD combined with MR angiography can be utilized to visualize the cyclical change of flow patterns of carotid bifurcation with different phases of a cardiac cycle.

Objective To study the effects of high matrix metalloproteinase 9 (MMP 9 ) on the biological behaviors of fibroblasts,in order to clarify the possible mechanisms in the wound healing of diabetic foot.Methods Establish the cell model of skin fibroblast with high expression of MMP 9 by high glucose (22.0 mmol/L) and high homocysteine (100 μmol/L) co-culture.Control group was incubated with normal glucose (5.5 mmol/L).Realtime PCR,ELISA and gelatin zymography were used to detect the MMP 9 mRNA,protein expression and activity of MMP 9.Flow cytometry,CCK-8,ELISA assay,scratch test and transwell were used to detect cell proliferation,viability,collagen (hydroxyproline) secretion,horizontal migration and vertical migration of cells.Results Data were expressed as (x- ± s).Differences were considered significant if their P value was ＜ 0.05.Results The expression of MMP 9 mRNA,protein levels and the activity of MMP 9 in high MMP 9 group were 6.05 folds,4.12 folds and 1.58 folds higher than those in control group (P ＜ 0.01,respectively).The proportion of S phase cells,proliferation index,cell viability,collagen (hydroxyproline) secretion,6 h horizontal migration rate and the number of vertical migration cells in high MMP9 group decreased by 29.8 ％,18.1％,23.3 ％,68.7 ％,45.0 ％ and 21.4 ％ than those in control group (P ＜ 0.01,respectively ). Conclusions Fibroblast with high expression of MMP 9 have decreased proliferation,activity,collagen secretion and reduced migration,which suggests that MMP 9 may inhibit the biological behaviors of fibroblasts.

Objective: To evaluate the safety and efficacy of intratumoral injection of polylactic-co-glycolic acid (PLGA) microspheres containing cobra venom cytotoxin in nude mice with transplanted human hepatoma. Methods: Cytotoxic activity of cytotoxin from cobra venom was determined by using methyl thiazolyl tetrazolium method in vitro. Microspheres containing cobra venom cytotoxin were prepared with a double emulsion-solvent evaporation method. Forty BALB/c nude mice were inoculated subcutaneously in right flank with hepatoma BEL-7404 cells. Thirty-two mice whose tumor size reached about 1.0 cm in diameter, were randomly assigned into normal saline group, blank microsphers group, cytotoxin group and cytotoxin-PLGA group. Nude mice were intratumorally injected with normal saline, blank microspheres, cytotoxin or cytotoxin-PLGA microspheres respectively. Internal echo characteristics and blood flow of tumors were observed by high-frequency ultrasound every week after treatment. Twenty-six days after treatment, the tumors were removed to calculate the inhibition rate of tumor growth. The tumor, heart, liver and kidney tissues were obtained for histopathological examination. Results: The cytotoxin separated and purified from crude cobra venom caused intense cytotoxic effects to the BEL-7404 cells in vitro. The diameter of PLGA microspheres containing cobra venom cytotoxin was about (34.45+/-9.85)mum. Encapsulation rate was up to (78.13+/-8.92)%, and cumulative amount of cobra venom cytotoxin released from the PLGA microspheres in vitro during 30 days was up to 84.3%. After intratumoral injection, tumor volumes and weights in the cytotoxin-PLGA group were lower than those in the normal saline group, with a tumor growth inhibition rate of 52.36%. Observed under a light microscope, most tumor tissues were necrotic. No obvious morphological change could be seen on the liver, kidney and heart tissues. Conclusion: The above findings indicate that intratumoral injection of cytotoxin-PLGA microspheres has strong antitumor effect and can obviously lessen systemic toxicity, which may provide an effective and feasible method for hepatocellular carcinoma treatment.

Objective To analyze the genetic model of attention deficit hyperactivity disorder(ADHD).Methods The segregation analysis and polygenic multiple threshold model were used to prove the polygenic model and to estimate the heritability and recurrence risk of ADHD in each degree relatives.Results 1. The average heritability of ADHD was (102.47?9.78)%;2.The first-degree relatives of probands were in high risk for ADHD(23.0%)compared with colony prevalence rate(2.6%). The ADHD prevalence of each degree relatives rapidly decreased with the increased magnitude of consanguineous relationship of each degree relatives and ADHD probands. Conclusions The genetic model of ADHD is the most likely polygenic inheritance with major genes, which suggested that the genetic factor might play an important role in the liability variance of ADHD.Apart from the involvement of multiple genes,each gene contributes a small additive effect,and the major genes may be involved as well.