The paper reviewed the research cooperation on public health between China and US in 30 years since the establishment of Sino-US diplomatic relation, based on the project database of Peking University, and made out the comments on the benefits, shortages and expectation in future cooperation.

Objective To evaluate the safety and immunogenicity of Shigella flexneri 2a conjugate vaccine.Methods A random and double blind study were carried out to compare the safety sero conversion rates and geometric mean titer(GMT)increase of Shigella flexneri 2a conjugate vaccine with phosphate-buffered saline used as control.Results The results showed that no severe systemic and local reaction rates occurred in trial group,which were not statistically significant compared with the control group.The seroconversion rate of both two weeks and twelve weeks after two doses(increased by 4 folds) were 86.27% and 79.74%;for GMT were 1∶361.83 and 1∶326.21 and increased averagely 1.08 and 0.98 times,which showed significant difference with those of the control group.Conclusion Shigella flexneri 2a conjugate vaccine was safe and its immunogenicity was good in group over 2 years old.Trialregistration National food drugs surveillance administrative bureau,"Medicine Clinical Experiment Written directive from a superior"2003L03808 number.

BACKGROUND: Apatite-wollastonite containing glass-ceramic (AWGC) is a kind of good bone repairing materials with excellent bioactivity, which is prepared by traditional melting process.OBJECTIVE: To observe AWGC prepared with sol-gel method and its bioactivity.DESIGN: Design experiment of materials process and in vitro bioactivity experiment.SETTING: College of materials science and Engineering of Sichuan University.MATERIALS: AWGC.METHODS: This experiment was conducted at the laboratory of College of Materials Science and Engineering of Sichuan University between August 2002 and May 2003. AWGC was prepared from sol-gel and followed by heattreating process. Bioactivity was investigated in vitro by immersing in the simulate body fluid (SBF) at 37 ℃ for 7 days . JL-1155 laser particle analyzer, X-ray diffraction, Fourier transform infrared spectroscopy and scanning electron microscope were used for micro-morphological structure analysis.MAIN OUTCOME MEASURES: ①The crystalline structure and microstructure of sol-gel derived glass-ceramic② The apatite forming process in simulate body fluid③ The diameter of the pore of the sol-gel derived apatite/wollastonite glass-ceramicRESULTS: ①Main crystalline phases of the sol-gel derived glass-ceramic materials were hydroxyapatite/fluoroapatite [Ca10(PO4)6(OH, F)] and β-wollastonite[β-CaSiO3]; Microstructure contained many micro-pores of 2-3μ m;② Sol-gel derived AW glass ceramic had excellent bioactivity: plenty of apatite granules were generated on the surface of the material after soaking for 7 days. ③Porous scaffolds possessed good macro-porous structure with the interconnected macro pores of 300-400 μm in diameter;CONCLUSION: Apatite-wollastonite containing glass-ceramic (AWGC)with excellent bioactivity was developed by sol-gel process. The material is expected to be a good candidate for bone-repairing and bone tissue engineering scaffold materials.

Objective To evaluate the feasibility and safety of establishing benign proliferative esophageal stenosis model by using stent implantation in experimental rats.Methods A customized self-expanding,metallic and straight tubular stent was used in this experiment (5 mm in diameter and 15 mm in length),on both sides at the stent's middle part there was a protruding barb that was used as a fixation device.Twelve healthy Sprague Dawley (SD) rats were randomized divided into group A (blank control group) and group B (stent implantation group),with 6 rats in each group.Esophageal stent implantation was employed in the rats of group B,and esophageal radiography was separately performed immediately,one and 4 weeks after stent implantation.All the experimental rats were sacrificed 4 weeks after stent implantation.The normal esophageal tissue of the rats in group A and the esophageal tissue at stent site of the rats in group B were collected and sent for pathological examinations,including gross morphology,light microscopy,etc.Results Successful stent implantation was achieved in all rats of group B,and the esophageal radiography performed immediately,one and 4 weeks after stent implantation showed no esophageal stent displacement;no severe complications occurred during the operation or follow-up period.Compared with group A,esophageal radiography reexamination performed 4 weeks after stent implantation in group B revealed that esophageal stricture at stent segment,caused by benign tissue hyperplasia,could be observed.The esophageal stent segment was taken out,its lumen was obviously narrowed under gross observation,and typical benign hyperplasia could be seen under optical microscope examination.Conclusion Using esophageal stent implantation to establish esophageal stenosis model is safe and feasible in experimental rats.The use of esophageal stent with barbs can significantly reduce the incidence of stent displacement.

Objective To study the clinical efficacy of recombinant human epidermal growth factor (rhEGF) in the treatment of sacrococcygeal decubitus ulcers grade Ⅲ with direct polymerizing suture after appling rhEGF to reinforce wound bed preparation (WBP). Methods From January 2007 to October 2009, 60 patients with sacrococcygeal decubitus ulcers Grade Ⅲ, were divided into control group and treatment group. The ulcer size was 3 cm × 4 cm to 10 cm × 12 cm and all ulcers were infected for 15-70 d. Treatment group received traditional dressing change and appling rhEGF to reinforce wound bed preparation. Control group received traditional dressing change only. The operative technique that we used in two groups was direct polymerizing suture. Cure rate of stage Ⅰ and complication morbidities were analyzed. Results Cure rate of stage Ⅰ was 87% in treatment group and 70% in control group. Complication morbidities were 13% in treatment group and 30% in control group. The difference between these two groups was statistically significant (P ＜ 0.05). Conclusion Appling rhEGF to reinforce wound bed preparation before operation could make subsequent treatment more effective and improve the cure ratio of operation with decreasing complications and morbidities. And more, dissecting under fascia possesses the advantages of easiness to perform and rich blood supply.The method of appling rhEGF with direct polymerizing suture is a simple, high efficient approach for the first repairment of sacrococcygeal decubitus ulcers grade Ⅲ, especially desirable for the elderly.

Objective To compare the difference in clinical prognosis of patients with low malignant obstructive jaundice treated by percutaneous biliary stent insertion across or above the duodenal papilla.Methods 56 patients with malignant biliary obstruction were reviewed retrospectively.Stents were placed above the duodenal papilla in 31 cases (group A) and across the duodenal papilla in 25 cases (group B).Total bilirubin reduction rate after 4-7 days of the procedure, biliary infection rate and stent occlusion rate were evaluated and compared between two groups.Results Mean survival periods were 180.3±142.5 days for group A and 178.6±137.7 days for group B (P=0.840).Total bilirubin level was decreased by 42.0±43.6% for group A and by 41.4±28.7% for group B after 4-7 days of the procedure(P=0.950);clinical success rates were 93.5% for group A and 92.0% for group B (P=1.0).Post-procedure cholangitis occurred in 7 cases (22.6%) in group A and 5 cases (20.0%) in group B (P=0.815).Stent occlusion rates were 22.6% and 28.0% for group A and group B (P=0.642).Conclusion For patients with lower malignant biliary obstruction, both of the two modalities of stent placement are safe and effective treatment.Stent placement across the duodenal papilla do not increase the development of stent occlusion or cholangitis compared with stent placement above the duodenal papilla.

Aim To explore the inhibitory effect of isobavachalcone (IBC)on migration and invasion of
tongue squamous cell carcinoma Tca81 1 3 cells and its possible mechanism.Methods Tca81 1 3 cells were
treated in different concentrations of IBC in vitro.Cell proliferation was detected by MTT;Wound healing as-say and Transwell chamber assay were used to detect the ability of cell migration and invasion;Western blot was applied to detect the expression of Akt,p-Akt, MMP-2 and MMP-9 proteins.Results IBC could in-hibit the proliferation of Tca81 1 3 cells in a concentra-tion-and time-dependent manner.IBC can reduce cell migration and invasion.Western blot showed that IBC could an decrease the expression of p-Akt,MMP-2 and MMP-9 proteins in a concentration-dependent manner.
However,the level of Akt was not affected by the con-centration of IBC treatment.Conclusion IBC could inhibit the proliferation, migration and invasion in Tca81 1 3 cells and its mechanism may be associated with the down-regulation of MMP-2 and MMP-9 pro-teins and the inhibition of phosphorylation of upstream Akt.

Objective：To investigate the changes of calcitonin gene-related peptide immunoreactive (CGRP-IR)nerve fibers in rat dental pulps during acute inflammation. Methods： Rat acute pulpitis model was established by silk thread ligation and the change of CGRP-IR nerve fibers was observed with immunohistochemical method.Results： In radical pulp,the CGRP-IR nerve fibers became denser and more heavily stained；in the coronal pulp,the number of CGRP-IR nerve fibers decreased,but the background staining was heavier. Conclusion： During acute inflammation,the amount of CGRP increases in dental pulps, and is released into the surronding tissue in a large scale in the coronal region.

Objective Acute massive pulmonary embolism(PE)is a clinical emergency requiring rapid and supportive measures.With the development of interventional technology and devices,percutaneous mechanical thrombectomy(PMT)is considered to be an alternative for the treatment of PE,though there is still relative lack of clinical experience.The purpose of this study is to evaluate the clinical efficacy and safety of PMT in the management of acute massive PE.Methods The clinical data of massive PE patients treated with interventional methods were collected and analyzed in a retrospective way.From Jan.2003 to Jan.2008,6 patients(5 males and one female,with a mean age of 62 years)with acute massive PE,which was initially diagnosed by computed tomography and finally confirmed by pulmonary angiography,were treated with percutaneous catheter fragmentation and/or Straub Rotarex thrombectomy device.Results The improvement of clinical status and restoration of blood flow in the main branches of pulmonary artery were obtained in all patients.Oxygen saturation(SaO2)increased from preoperative(79.5±5.3)%to postoporative (92.8±3.4)%,with P＜0.01.Partial arterial oxygen pressure(PaO2)increased from preoperative(58.0±9.8)mmHg to postoperative(88.7±4.1)mmHg(P＜0.01).After PMT treatment,the mean pulmonary artery pressure(PAP)decreased from preoperative(40.8±7.8)mmHg to postoperative(29.8±8.0)mmHg (P＜0.01).Miller index decreased from preoperative 0.54±0.03 to postoperative 0.18±0.07(P＜0.01).During a clinical follow-up period ranged from 1 to 5 years,four patients showed no recurrence of PE,the other two patients lost touch with the authors.Conclusion The preliminary experience in onr series suggests that PMT is an easy,effective and safe therapy in the clinical management of acute massive PE,especially when thrombolysis is contraindicated.

Objective To explore the ideal choice of feeding artery which is used for regional arterial infusion (RAI) in severe acute pancreatitis. Methods Forty-five patients with SAP were treated with RAI. The ideal feeding artery was that can supply entire pancreas according to arteriography and can maximize concentration of drug at pancreatic tissue. The pancreatic arteriography was considered as the final objective evidence for choice. Results (1)Gastroduodenal artery was chosen as feeding artery in forty-four cases, and superior mesenterlc artery was chosen in only one case because of vascular abnormity. (2)According to splenic arteriography, blood of splenic artery was supplied to spleen chiefly, and only partial tail of pancreas was applied by splenic artery. (3)According to celiac trunk arteriography, blood of celiac trunk could be supplied to entire pancreas, but a considerable proportion of the total blood was supplied to spleen through splenic artery and liver through hepatic artery proper.Therefore, the drug utilization index was lower. (4)According to gastroduodenal arteriography, blood of gastroduodenal artery could be supplied to entire pancrea, and almost all of the blood that contains drug flowed into pancreas. Therefore, the drug utilization index was higher. Conclusions Gastroduodenal artery is the ideal choice of artery which is used for regional intra-arterial infusion in sever acute pancreatitis. Pancreatic arteriography should be applied routinely when yever acute pancreatitis was treated with RAI.