BACKGROUND: Scaffolds are an important part in bone tissue engineering. However, no perfect scaffolds have been developed for bone tissue engineering yet.OBJECTIVE: To evaluate the repair of rabbit radial defects by poly (L-lactic acid)/tricalcium phosphate(PLLA/TCP) scaffolds prepared by rapid prototyping(RP) technology so as to find a new carrier for growth factors.DESIGN: A completely randomized controlled study was conducted. SETTING: Orthopaedic institute of a military medical university.MATERIALS: The study was conducted in the General Orthopedic Institute,Fourth Military Medical University of Chinese PLA, from May 2001 to February 2002. Twenty clean New Zealand rabbits with body mass of(2.5 ±0. 5) kg for this study were obtained from the Experiment Animal Center of Fourth Military Medical University of Chinese PLA. The animals were divided into experiment group and control group with 10 rabbits in each group.INTERVETIONS: PLLA/TCP scaffolds prepared by RP technology and loaded with or without bovine bone morphogenetic protein (BMP) were used to repair the rabbit radial defects of 15 mm.MAIN OUTCOME MEASURES: Main outcomes: ① microscopic observation results of transplanted materials of the two groups; ② degradation rate of scaffolds. Secondary outcomes: ① gross observation; ② radiographic results; ③ bone density.RESULTS: At week 12, bone defect healing in experiment group was good. X-ray examination showed continuous bone callus and partial molding of different degrees. Degradation rate of scaffolds was 39.6%, and bone density in the defected part reached 70% of the normal level. All the indexes of experiment group were superior to those of control group, and no healing was found in the defected area in control group.CONCLUSION: PLLA/TCP scaffolds prepared by RP technology and loaded with bovine BMP can repair radial defects of 15mm in rabbits.

BACKGROUND:In 1990s,overseas researchers use balloon occlusion method for establishing closed-chest animal models of myocardial infarction. But,ventricular fibrillation and thrombosis of intraoperative factors reduce the success rate of establishing the models. Currently,there are a few reports on establishing the large animal models. OBJECTIVE:We used balloon occlusion method for establishing closed-chest swine models of myocardial infarction,and explored ways to improve the success rate of modeling. DESIGN,TIME AND SETTING:The randomized controlled animal study of pathology observation was performed at the Department of Cardiology,First Affiliated Hospital of Kunming Medical College and Research Room of Pathology,Kunming Medical College from July 2008 to May 2009. MATERIALS:Fifteen Diannan small-ear pigs weighing 19-25 kg,aged 8-11 months,were divided into three groups:sham operation group,ischemia-reperfusion group,and ischemic postconditioning group,with 5 pigs in each group.METHODS:After the coronary occlusion and reperfusion period,the prophylactic use of lidocaine (1.0-2.0 mg/kg) infusion to control arrhythmia,and use of heparin to prevent and treat the thrombosis. A balloon catheter was positioned in the distal end of the first diagonal branch of the left anterior descending (LAD) artery under fluoroscopic guidance. In the sham operation group,the balloon was only placed to the LAD,did not block coronary artery. In the ischemia-reperfusion group,inflatable balloon occlusion was done for 60 minutes in the LAD after the balloon removed. In ischemic postconditioning group,after the balloon was inflated and occluded the LAD for 60 minutes,ischemic postconditioning was elicited by eight cycles of 30-second reperfusion,followed by 30-second reocclusion.MAIN OUTCOME MEASURES:Coronary angiography,electrocardiogram (ECG) and cardiac enzymes test was conducted to evaluate models of myocardial infarction. After three days,cardiac 2,3,5-triphenyltetrazolium chloride (TTC) staining and pathological examination was done to verily myocardial infarction.RESULTS:In the sham operation group,all pigs survived. In the ischemia-reperfusion group,4 pig models of myocardial infarction were successfully established,and one died of refractory ventricular fibrillation. In the ischemic postconditioning group,models of myocardial infarction after ischemia were successfully established. Following distal left anterior descending artery occlusion,the ECG leads V13 on the ST-segment elevation,the sick rational Q-wave formed;myocardial enzyme evolution of myocardial infarction in the human body was basically the same process. The site of myocardial infarction,basically the same parts,was located in apical,left ventricular anterior wall,and the former interval. TTC staining was normal myocardium brick red,myocardial infarct area appeared pale;pathological examination revealed a normal structure of myocardial infarct damage,cytoplasm condensed,dyeing deepening,transverse striations disappeared,nuclear enrichment,dissolution,fragmentation,many erythrocytes around the infarct area with abundant granulation tissue and a large infiltration of inflammatory cells.CONCLUSION:The described model presents a less invasion to the animals,and is the closest to the process of clinical practice.Intraoperative use of lidocaine and heparin for controlling arrhythmia and thrombosis of the models is successfully established as an effective manner. Ischemic postconditioning may be one of the factors for improving the modeling success rate.

Objective To evaluate the result of fresh autologuos pericardium for the reconstruction of new pulmonary arterial root in arterial switch operation (ASO). Methods Between January 2004 and June 2010, 63 consecutive infants with congenital heart disease were treated with ASO. A new pulmonary arterial root was reconstructed with a fresh autologuos pericardium which clipped pants-like. The followed up time was 3 months to 6 years after discharge. Patients were reexamined consecutively at 3- and 6-month; 1-, 2- and 6-year. Two-dimensional echocardiography was performed for measuring the pulmonary artery diameter. The pulmonary arterial blood speed was measured by continuous Doppler during systole. The pulmonary flow and the pulmonary artery diameter of healthy children of same age were also measure as control group. Simplified Bernoulli formula was adopted to calculate the pressure gradient through pulmonary artery anastomose for, evaluating whether it had pulmonary stenosis or not. Results Fifty seven infants were cured and discharged. Forty nine patients were finished follow up with a mean duration of( 18 ±4) months. The blood speed in the pulmonary artery anastomosis was 0.70 -2.16 m/s with a mean of (1.31 ±0.40) m/s. No pulmonary stenosis was found with the simplified Bernoulli formula. There was no significant difference regarding the pulmonary diameter and the pulmonary artery flow velocity as compared with the normal children of the same age. Conclusion The fresh autologuos pericardium is reliable for reconstruction of new pulmonary arterial root in ASO.

BACKGROUND: Recent trials and clinical studies have shown that intracoronary transplantation of bone marrow-derived mesenchymal stem cells (MSCs) improves cardiac function following acute myocardial infarction (AMI). However, whether homing of MSCs into the infarcted myocardium or not is still unknown.OBJECTIVE: To study the homing of MSCs intracoronary administration in porcine myocardial infarction model using in vivo magnetic resonance imaging tracking.METHODS: Porcine MSCs were isolated and cultured by the whole bone marrow method. Following labeling by superparamagnetic iron oxide (SPIO), MSCs were treated with trypsinization to adjust the concentration at 10~(10)/L. Myocardial infarction was induced in all 10 pigs. At one week after modeling, the labeled MSCs were delivered via intracoronary infusion with standard over-the-wire (OTW) balloon angioplasty catheters. Prussian blue staining was used to evaluate labeling efficiency, and double echo steady state was used to scan four-chamber and cor biloculare at long axis view, which was considered as locating phase to obtain image of left ventricle at short axis view. RESULTS AND CONCLUSION: MSCs could be efficiently and safely labeled with SPIO. Intracoronary transplantation of MSCs is able to home the sites of myocardial injury and the border between infarcted and normal tissue. MRI can track SPIO-labeled MSCs delivered through intracoronary and were confirmed on pathology. After 5 weeks the injected labeled cells could still be detected with MRI.

Objective To compare the long-term outcomes of partial hepatectomy versus choledocholithotomy both combined with choledochoscopy,for the treatment of hepatolithiasis.Methods Patients who underwent either type of the operations were followed up and examined using hepatobiliary magnetic resonance (enhanced MRI + MRCP).The incidences of abnormal imaging in the two groups were compared.Results Of 268 patients,138 patients underwent partial hepatectomy and the remaining 130 patients underwent choledocholithotomy.When hepatectomy was compared with choledocholithotomy,the recurrence rate of acute cholangitis combined with bile duct stone (5.8％ vs.21.5％),the reoperation rate (5.8％ vs.21.5％),the bile duct stricture rate (8.0％ vs.44.6％),the abnormal liver parenchyma perfusion rate (4.3％ vs.23.1％),the incidence of intrahepatic bile duct enhancement or thickening (1.5％ vs.26.9％),the incidence of hepatic atrophy (3.0％ vs.30.0％) and the incidence of cholangiocarcinoma (0 vs.2.3％) were better.Conclusions The long-term adverse outcomes were significantly worse in the choledocholithotomy group than in the partial hepatectomy group.Choledocholithotomy combined with choledochoscopy should only be considered as a complementary procedure to partial hepatectomy in hepatolithiasis.

OBJECTIVETo evaluate the effects of repairing rabbit radial defects with polyester/tricalcium phosphate scaffolds prepared by rapid prototyping technology loaded with bovine bone morphogenetic protein (bBMP), and find new carriers for growth factors.

METHODSPolyester/tricalcium phosphate scaffolds prepared by rapid prototyping technology loaded with and without bovine BMP were used to repair the 15 mm radial defect in rabbit. Then the results of radiography, histology, scaffolds degrade rates and bone mineral density (BMD) were appraised to examine the effects at the 12th week.

RESULTSAt the 12th week postoperatively, all defects treated with bBMP were radiographically repaired. No radius implanted polyester/tricalcium phosphate scaffolds without bBMP showed radiographic and histological union. At experimental groups, longitudinal alignment of lamellar structure was observed histologically at the 12th week, indicating that remodeling of regenerated bone was complete in different degree. Of the three experimental groups, the bony regeneration and remodeling of callus in poly lactide-co-glycolide/tricalcium phosphate (PLGA/TCP) group was the best. The BMD values were beyond 70% of normal value at the 12th week while the PLGA/TCP scaffolds group was the highest, and no abnormalities were observed in the surrounding soft tissue in all groups.

CONCLUSIONSPolyester/tricalcium phosphate scaffolds prepared by rapid prototyping technology loaded with bovine BMP can repair a 15 mm radial defect of rabbit. As for the results, the PLGA/TCP scaffold is ideal and better than poly L-lactide-co-D, L-lactide (PDLLA/TCP) scaffold, but the ploy L-lactic acid (PLLA/TCP) is not so good for its low degradation rates.

Animals ; Bone Density ; Bone Morphogenetic Proteins ; Bone Regeneration ; Bone Substitutes ; therapeutic use ; Calcium Phosphates ; therapeutic use ; Polyesters ; therapeutic use ; Rabbits ; Radiography ; Radius ; diagnostic imaging ; pathology ; surgery

Polyethylene glycol-polybenzyl-L-glutamate copolymer (PEG-PBLG) was synthesized and paclitaxel-loaded core-shell type nano-micelles with amphiphilic copolymer PEG-PBLG was prepared by the dialysis method. The drug loading content and entrapment efficiency were determined by HPLC. The average size and its distribution were determined by dynamic light scattering method. The paclitaxel release rate in vitro from micelles was measured by HPLC. The cell cytotoxicity in vitro was observed with MTT assay. The anti-tumor activity of paclitaxel-loaded micelles were evaluated in tumor-inhibiting test of nude mice using human liver cancer HepG-2. The results indicated that paclitaxel could be entrapped in PEG-PBLG copolymer micelles and its size was in the range of 80-265 nm which increased with an increase in molecular weight of PBLG in copolymer; in vitro the paclitaxel could be released sustainably from the micelles. In high concentration of paclitaxel (>20 microg x mL(-1)) the paclitaxel-loaded PEG-PBLG micelles displayed much less cell cytotoxicity than paclitaxel injections with Cremophor EL (P<0.05); the tumor inhibiting activity of paclitaxel-loaded PEG-PBLG micelles was similar to that of paclitaxel injections with Cremophor EL in the same paclitaxel concentration. It was concluded that the paclitaxel-loaded PEG-PBLG micelles had more uniform size and size distribution, excellent drug sustainable-release behavior, less cytotoxicity, good anti-tumor activity similar to paclitaxel injections with Cremophor EL. So paclitaxel-loaded PEG-PBLG micelles would be a novel paclitaxel preparation in clinic for the treatment of tumor.
Animals ; Antineoplastic Agents, Phytogenic ; pharmacology ; Cell Line, Tumor ; Delayed-Action Preparations ; Drug Delivery Systems ; Humans ; Liver Neoplasms, Experimental ; pathology ; Mice ; Mice, Inbred BALB C ; Mice, Nude ; Micelles ; Nanoparticles ; Neoplasm Transplantation ; Paclitaxel ; pharmacology ; Particle Size ; Polyethylene Glycols ; chemistry ; Polyglutamic Acid ; analogs & derivatives ; chemistry ; Polymers ; Random Allocation

AIM and METHODS: Chemotactic migration of peripheral blood mononuclear cell(PBMNC) of healthy blood donors(BD) and patients with blood stasis syndrome(BSS) across polycarbonate membrane(PCM) and human umbilical vein endothelial cell(HUVEC) monolayer, IL-8 produced by migrat PBMNC and effects of protocatechuic aldehyde(PCA) on the process mentioned above were investigated. RESULTS: 1) The numbers of migrating PBMNC in group BSS was higher than that in group BD(P

Objective The aim of this study was to systematically evaluate the health status of Asian immigrants in Canada and the associated factors. Methods Using data from the 2003 Canadian Community Health Survey, a descriptive analysis was performed to estimate the frequency of health associated factors among different populations. Age-standardization rates was also used to compare the prevalence of chronic conditions among Asian immigrants, other immigrants and native residents. Logistic regression analysis was used to estimate the adjusted Odds ratio (0R) associated with each health outcome and 95% confidence interval (95%CI) after controlling for potential confounding factors. Results After age-standardization, Asian immigrants had a similar prevalence of 1-5 chronic conditions and a lower prevalence of 5+ chronic conditions (3.56%) compared with non-immigrants (5.31%). Asian immigrants were less likely to report any chronic disease (0R=0.49, 95% CI: 0.46-0.51) than non- immigrants (0R=1.00). Recent Asian immigrants were less likely to report any chronic condition (0R=0.34, 95% CI: 0.31-0.37) than long-term Asian immigrants (0R=0.62, 95% VI: 0.58-0.66). After adjusting for socioeconomic status and lifestyle factors, Asian immigrants had a slightly changed risk of four chronic conditions with exception of heart disease. Conclusion Asian immigrants had lower risk of chronic conditions as a whole, however, these health advantages decreased along with increasing length of residence in Canada. Socioeconomic factors and lifestyles cannot fully explain the differences of health status between Asian immigrants and non-immigrant Canadians reported in this paper.

Inosine 5′-monophosphate dehydrogenase (IMPDH) is a key enzyme catalyzing the rate-limiting step of de novo nucleotide synthesis in vivo. In recent years, it has become a therapeutic target for anti-virus, anti-bacterial, anti-cancer, anti-parasitic and other diseases. IMPDH inhibitors have been shown to inhibit viral prolife-ration in host cells by depleting guanosine 5′-monophosphate (GMP), the raw material required for viral replication in host cells, with broad-spectrum antiviral properties. In order to find novel anti-coronavirus drugs, this study screened 22 potential IMPDH inhibitors from 70 000 natural small molecule libraries based on IMPDH protein structure using molecular docking and ROC calculation for virtual screening. With ribavirin as the positive control drug, Huh7 cell and H460 cell models were used to verify the anti-coronavirus HCoV-229E and HCoV-OC43 activities of 22 selected target compounds. Among them, compounds 11, 12, 15 and 16 showed inhibitory activity against coronavirus HCoV-229E. The compounds 4, 12, 13 and 15 showed inhibitory activities against coronavirus HCoV-OC43. 12 and 15 showed significant inhibitory activity against both two coronaviruses, and their efficacy was similar to ribavirin at the same dose, which can be further studied as a lead compound for IMPDH inhibitors.