Nonlinear numerical model analysis of circumferential stress on human aortic arch / 医用生物力学

Objective To provide reference for understanding the stress state of the aortic arch，select the appropriate constitutive relation, further analyze the biomechanical properties of human aortic arch so as to offer the biomechanical basis for treating aortic arch in clinic. Method Under two different constraints(the first constraint: the constraint along with the direction of ascending aorta; the second constraint: the ascending aorta could move freely, but the end was closed with a hemisphere), three constitutive relationships (linear constitutive, exponential function constitutive, M-R constitutive) and two loads(10.67 kPa and 26.66 kPa), the circumferential stress on human aortic arch were studied by the finite element method, and the results were also discussed. Results The models under two constraints were established and the contour plot of circumferential stress and its distribution along the arc of aortic arch under two constraints, three constitutive relationships and two loads were obtained respectively. Conclusions The exponential function constitutive model could reflect the mechanical properties of aortic arch more comprehensively and the mechanical properties of aortic arch could be reflected more factually under the second constraint.

Associations of triple-phase enhancement multi-slice CT scan with histological differentiation and lymphovascular invasion in gastric cancer / 中华胃肠外科杂志

<p><b>OBJECTIVE</b>To explore the associations of triple-phase enhancement multi-slice CT scan with histological differentiation and lymphovascular invasion in advanced gastric cancer.</p><p><b>METHODS</b>Patients with gastric cancer undergoing surgical resection between January 2006 and December 2009 were included, all of whom underwent routine and two-phase contrast enhancement multi-slice CT examinations of the upper abdomen before surgery. Patients with incomplete data were excluded. Postoperative specimens were used for evaluation of histological differentiation, microscopic lymphovascular invasion, and CD34 and D2-40 expression. Associations between contrast enhancement ratio (CER) of triple-phase multi-slice CT scan and differentiation as well as lymphovascular invasion were analyzed.</p><p><b>RESULTS</b>A total of 64 patients were included. There were significant associations between CER and tumor differentiation (P<0.05). Compared to those without microvascular invasion, CER of the arterial phase in gastric cancer with microvascular invasion was significantly higher (0.61±0.28 vs. 0.46±0.14, P<0.05), and that of the arterial-parenchymal phase was significantly lower(1.81±0.39 vs. 2.28±0.80, P<0.05). However, gastric cancers with lymphatic invasion were associated with significantly higher CER of the parenchymal phase than their counterparts(1.25±0.57 vs. 1.00±0.35, P<0.05).</p><p><b>CONCLUSION</b>CER of triple-phase multi-slice CT scan can reveal the differentiation of gastric cancer and is associated with microvascular and lymphatic invasion.</p>

Multi-slice CT contrast-enhanced presentations of advanced gastric cancer: associations with histo-differentiation and expression of p53 and P-glycoprotein / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>This study aimed to investigate multi-slice CT contrast-enhanced presentation of gastric cancer and its correlation with histo-differentiation and p53 and P-glycoprotein (P-gp) expression.</p><p><b>METHODS</b>Sixty-six patients with gastric cancer in the present study underwent a multi-slice CT preoperative routine and dual-phase contrast-enhanced examination of the upper abdomen; postoperative specimens were used to determine histo-differentiation and the expression of p53 and P-gp. The correlation of multi-slice CT contrast-enhanced presentation with histo-differentiation and expression of p53 and P-gp was analyzed.</p><p><b>RESULTS</b>The dual-phase contrast-enhanced ratio (CER) was not correlated with the histo-differentiation of gastric cancer (P > 0.05). Positive expression of p53 and P-gp was significantly higher in the cases of layered or heterogeneous enhancement than in the cases of homogenous enhancement (P < 0.05). Positive expression of p53 was also correlated with the arterial phase CER, tumor size and lymph node metastasis (P < 0.05), but not with infiltration thickness of the gastric wall, nor was it correlated with the portal phase CER (P > 0.05). Positive expression of P-gp was only correlated with the portal phase CER (P = 0.005).</p><p><b>CONCLUSIONS</b>Differently enhanced pattern and CER of the arterial and portal phase in gastric cancer correlate with its different histo-differentiation and expression of p53 and P-gp respectively. In addition, tumor size and lymph node metastasis of gastric cancer relate to the expression of p53.</p>

The reconstruction of neovascularization of posterior pharyngeal flap: an experimental study in dogs / 中华整形外科杂志

<p><b>OBJECTIVE</b>To elucidate the reconstruction of neovascularization that occurred in the superiorly and inferiorly based posterior pharyngeal flaps in different time postoperatively.</p><p><b>METHODS</b>Ten mongrel dogs were randomly divided into two experimental groups, which were performed superiorly or inferiorly based posterior pharyngeal flap surgery respectively. Each group was then subdivided into five subgroups, and were sacrificed immediately after operation or on 3, 7, 30, 90 day postoperative respectively. Microangiography was used to exhibite the vessel.</p><p><b>RESULTS</b>1. The blood vessel reconstruction of the superiorly based posterior pharyngeal flap was more rapid compared with the inferiorly based flap. The 3-day flap has established an axial vascular network, which was mature on the 30-day flap. The superiorly based posterior pharyngeal flap was mainly supplied by the pedicle. 2. The blood vessels reconstruction of the inferiorly based posterior pharyngeal flap was firstly occurred in the pedicle and apex of the flap, which grew slowly to the middle of the flap. The inferiorly based posterior pharyngeal flap was supplied by the pedicle and the soft palate. A mature axial vascular network was exhibited on the 90-day flap, which was not mature on the 30-day flap.</p><p><b>CONCLUSION</b>Both superiorly and inferiorly based posterior pharyngeal flap can establish an axial vascular network and gain ample blood supply.</p>

The value of MR angiography in the diagnosis of deep vein thrombosis of the lower limbs:comparative study with DSA / 中华放射学杂志

Objective To assess the clinical values of MR angiography(MRA)in the detection of deep vein thrombosis of the lower limbs.Methods Two-dimensional time of flight(2D TOF)MRA was performed in thirty patients who were suspected of having deep vein thrombosis in the lower limbs.The findings of MRA were compared to that of digital subtraction angiography(DSA).Results twenty-five cases showed deep vein thrombosis in the lower limbs,the MRA findings included venous filling defect (14 cases),occlusions and interruptions of veins(8 cases),venous recanalizations(3 cases),collateral veins(25 cases).Taking the results of DSA as a golden standard,MRA detected all of the affected cases with only one case as the false positive.Conclusion 2D TOF MRA is a method of choice in the diagnosis of deep vein thrombosis of the lower limbs.