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Rapid progress in tissue engineering research in past decades has opened up vast possibilities to tackle the challenges of generating tissues or organs that mimic native structures. The success of tissue en-gineered constructs largely depends on the incorporation of a stable vascular network that eventually anastomoses with the host vasculature to support the various biological functions of embedded cells. In recent years, significant progress has been achieved with respect to extrusion, laser, micro-molding, and electrospinning-based techniques that allow the fabrication of any geometry in a layer-by-layer fashion. Moreover, decellularized matrix, self-assembled structures, and cell sheets have been explored to replace the biopolymers needed for scaffold fabrication. While the techniques have evolved to create specific tissues or organs with outstanding geometric precision, formation of interconnected, functional, and perfused vascular networks remains a challenge. This article briefly reviews recent progress in 3D fab-rication approaches used to fabricate vascular networks with incorporated cells, angiogenic factors, proteins, and/or peptides. The influence of the fabricated network on blood vessel formation, and the various features, merits, and shortcomings of the various fabrication techniques are discussed and summarized.
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Objective To evaluate the utility of MMP9,MPO and sCD40L in detection of the character of coronary artery plaque.Methods From April 2008 to January 2010,118 patients from outpatient of Fu Wai Hospital with chest pain were enrolled.All of them underwent 64 Multiple-detector row spiral computer tomography (64-MDCT),the CT value ＜ 130 Hu patients were enrolled in non-calcified plaque group (71 cases),CT value ≥ 130 Hu patients were enrolled in the calcified plaque group (47 cases).Ninty healthy volunteers were selected as the control group.Enzyme-linked immunosorbent assay (ELISA) was used to detect the levels of serum markers,including MMP9,MPO and sCD40L.Levels of MMP9,MPO and sCD40L of each group were compared.ROC curve was used to evaluate the sensitivity and specificity of the markers in diagnosis of non-calcified plaque.Results MMP9,MPO and sCD40L levels of non-calcified were ( 762.25 ± 368.71 ),[ 844.10 (582.00 - 1220.70) ],(9.37 ± 3.15) μg/L,higher than the healthy control group (342.70 ± 178.53),[426.35 ( 283.20 - 592.00) ],(6.55 ± 2.96) μg/L and calcified plaque group ( 483.12 ± 219.09 ),[ 469.00 ( 302.45 - 723.55) ],( 7.24 ± 2.86) μg/L The difference was statistically significant ( F =42.47,H =50.28,F =17.94,all P ＜ 0.01 ). Areas of MMP9,MPO and sCD40L under the ROC curve to predict non-calcified plaque were 0.854,0.792,0.751 respectively,when the identification threshold for non-calcified plaque were 510.13,537.82,7.05 μg/L respectively,the diagnostic sensitivity was 80％,80％,80％ respectively,and specificity was 80％,67％ and 55％ respectively.Conclusion The serum MMP9,MPO and sCD40L levels can help to determine the character of coronary plaque.
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Objective To analyze the image quality of coronary arteries by dual-source computed tomography (DSCT) in children with congenital heart disease(CHD). Methods Image quality of coronary arteries were scored by two radiologists with an ordinal grading system. Score 3 or 4 was considered to be good image quality and diagnostic. Score differences among 3 groups of various baseline heart rate levels, 3 groups of various age levels and 4 coronary branches were analyzed by using ANOVA. Multiple linear regression analysis was used to test the effects of age, heart rate, tube voltage, tube current, pitch, contrast volume, contrast injection rate on the coronary image scores. Results A total of 72 consecutive patients were enrolled. 71.2% (205/288) of coronary artery branches was good enough for diagnosis. Image quality of left main coronary artery (LM, score 3.64±0.49), left anterior descending (LAD, score 2.97±0.40), right coronary artery (RCA, score of 2.82±0.70), left circumflex (LCX, score 2.76±0.73) were in a descending order (F=29.00, P<0.01). Image scores of age groups of 0--1 years old (2.80±0.65), >1--3 years old (2.81±0.74), >3--14 years old (3.58±0.52) were in an ascending order (F= 20.16,P<0.01). Image scores of heart rate groups of<100 bpm (3.54±0.56),100--150 bpm (2.86± 0.70) and >150 bpm (2.81±0.63) were in a descending order (F=16.72, P<0.01). Multiple linearregression analysis demonstrated that multiple impact factors affected image quality of LM, LAD, LCX and RCA. Age(r=0.013 ,P<0.01)and contrast volume(r=0.292, P<0.01)had positive correlation with LM score. Age(r=0.509, P<0.01) and voltage (r=0.292, P=0.011) had positive correlation with LAD score. Heart rate(r= -0.179, P<0.05) had negative correlation with LAD score. Age (r=0.063, P< 0.01) had negative correlation with LCX score. Age (r=0.486,P<0.01) and voltage (r=0.220, P<0.05) had positive correlation with RCA score. Conclusions Dual-source CT could clearly shows coronary arteries of children with CHD over the age of 3 or with heart rate less than 100 bpm. Limitations of Dual-source CT coronary angiography for CHD children included young age and fast heart rate.
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Objective To evaluate the value of MSCT, MRI and SPECT in detecting acute myocardial ischemia in Chinese mini-swine model. Methods A total of six male mini-pigs were recruited with a mean body weight of (21.6 ± 1.2) kg. All pigs were scanned on MSCT before the ligation of distal segment of Left anterior descending artery. Then, MSCT was rescanned every 2 h from ligation till 8 h latter.MRI, SPECT and the last MSCT scan were performed within 24 h one by one. Finally pathological examination was carried out right after the pig killed. Results One pig died during operation, the other 5 finished all the examinations. The pathological staining showed the same areas of myocardial infarction in the left ventricular anterior wall with the all the imaging findings, including low perfusion region of MSCT arterial phase at 2-24 h, low perfusion region of SPECT at 24 h and low perfusion region of MRI first pass phase at 24 h. Three of 5 pigs showed enhanced edge of low perfusion region on MSCT delayed scan at 4-8 h. The mean CT values in the region with reduced first-pass perfusion were 75.9,36.4, 35. 2,37. 8,37.4,33.3 HU on MDCT image at baseline, 2-8 h after operation and within 24 h after operation, respectively,and there were statistically significant difference of CT values ( F = 12. 341, P ＜0. 01 ) between preoperative and all postoperative MSCT scan. There were no statistically significant difference (F = 2. 278, P = 0. 792)among all postoperative MSCT scan. At baseline, 2-8 h after operation and within 24 h, the average volumes of stroke volume(SV)were 21.7,11.9,10.3,11.4,12. 3,12.6 ml, respectively, while the average volume of end-systolic volume( ESV)were 15.2,23.4,25.0,24. 4,25.3,22. 8 ml,respectively. The average volume of end-diastolic volume ( EDV ) at these time point were 37. 0,35.4,35.0,35.7,37. 6,37.5 ml,respectively and the average percentage of ejection fraction (EF) were 58.9% ,33.8% ,29. 0%, 31.9%,32.6% ,33.5% ,respectively. SV(F =22. 349, P＜0.01) ,ESV (F=8. 810, P＜0.01) ,EF(F =27. 240,P ＜ 0. 01 ) were all significantly different among all postoperative MSCT scan except EDV ( F = 2. 339, P =0. 079). Infarct size, which was defined as the proportion of the area of infarction to that of the entire heart,were (39.4 ±12.6)% for MSCT,(37.2 ± 10.0)% for MRI, (35.9 ±9.6)% for TTC, respectively.There were no significant differences of infarct size between TTC and MSCT (t =0. 612, P =0. 574), TTC and MRI (t=0.820, P=0.458), MSCTand MR (t=0. 425 ,P =0. 692 ). Conclusions MSCT,MRI and SPECT were all able to be used to detect the myocardial infarction in acute myocardial ischemia model The infarct size defined on MSCT, MRI and pathology were consistent. The density of ischemic myocardium and cardiac function did not change over the time within 24 h right after infarction.
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Objective To assess multi-detector CT (MDCT), MR and single photon emission computed tomography (SPECT) in detection of chronic myocardial ischemia in Chinese mini-swine models. Methods Six male pigs received MDCT scan firstly. Then Ameroid narrow ring was placed in the left descending branch and MDCT, MR were performed at the same day. On the 2nd, 27th day, SPECT was given. Coronary angiography (CAG) was given on the 28th day, and then MDCT and MRI. The animals were killed after allexaminations. The pathological examination was given at last. Results Two pigs died during the rearing and another 4 had results. Pathology showed 3 had subendocardium infarction and 1 had no infarction. CAG showed infarction in 3 pigs with stenosis more than 50%. Areas of reduced perfusion in arterial phase MSCT, first-pass MRI and SPECT were consistent to findings of TTC staining. MDCT detected that ESV on the 28th day was higher than that of preoperative and postoperative day (P0.05). CT value of left ventricular anterior wall on preoperative, postoperative day and the 28th day were statistically different (F=10.274, P=0.011). Conclusion Arterial phase of MDCT, first-pass perfusion of MRI and SPECT all show reducing perfusion in left ventricular anterior wall corresponded to myocardial infarction with TTC staining. CT value of myocardial ischemia decreases after myocardial ischemia.
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Objective To study the correlation between morphological characteristics of coronary artery calcified plaques and luminal stenosis of local coronary artery segments with 64-slice computed tomography.Methods One hundred and eleven patients who had undergone 64-slice computed tomographic coronary angiography(CTCA)and conventional coronary angiography(CAG)were retrospectively analyzed.The calcified plaques were classified as punctate,nodular,strip-like and nubbly in long-axis view of coronary artery lumen,and were classified as crescent,semilunar,round moon and circinate in short-axis view.The morphologic characteristics of these calcified plaques on CTCA were retrospectively analyzed and compared with luminal stenosis of CAG results.Results Among 528 calcified coronary segments which were analyzed in 111 patients,there were 383(72.5%)punctate calcified plaque segments and 145(27.5%)of non-punctate plaques.There were 34(23.4%,34/145)non-punctate calcified plaques which caused severe stenosis(≥75%),including 4(11.8%)nodular,8(23.5%)stripe-like and 22(64.7%)nubbly calcified plaques on the long-axis view,and 0(0.0%)cresent,8(23.5%)semilunar,18(52.9%)round moon and 8(23.5%)circinate calcified plaques on the short-axis view.The ratios of different morphological coronary artery calcifications which caused severe stenoses were significantly different with each other(all P＜0.01).Conclusion Different figures of coronary artery calcified plaques demonstrate different degrees of stenoses of local coronary artery lumen.Severe stenoses were mostly caused by nubbly calcified plaque on long-axis view,round moon and circinate calcified plaque on short-axis view.