Objective Eight functional fragments of the novel A/H1N1 influenza pandemic virus in 2009 had their own evolutionary characteristics.Among them,the hemagglutinin(HA),the major antigenic gene,was originated from swine influenza virus epidemics in North America.The HA gene,polymerase genes(PB2,PB1 and PA),nucleoprotein gene(NP) and nonstructural protein gene(NS) of the virus strain isolated in Iowa of US in 2005 shared close homology(identities more than 90%) with the corresponding sequences of the novel A/H1N1 influenza pandemic virus in 2009.The Iowa strain might be an intermediate step of the evolutionary process of this novel A/H1N1 influenza virus.The evolutionary process of the novel A/H1N1 influenza might be realized in pigs re-assorted with the neuraminidase(NA) gene from European swine H1N1 influenza virus and matrix proteins(M1 and M2) genes from European H3N2 swine influenza virus.The present paper presented possible evolutionary processes of the novel A/H1N1 influenza pandemic virus in 2009,and pointed out several relevant scientific points which should be emphasized in the prevention and control of the epidemics of the novel A/H1N1 influenza in near future.

Infrastructures of the active surveillance system of emergent public health events consists of the following factors: cases of infectious diseases, symptoms in the Emergency Department of hospitals, etiological examination in the public health laboratories, medication sales and medical supplies sales, public symptoms in metropolitan, absenteeism in elementary and middle schools, animal death, medical emergency service, and unexplained deaths, etc . Active surveillance is able to discover emergent public health events promptly and provide evidences for initiating immediate response system and public health crisis management in China. Research on active surveillance of the emergent public health event should be enforced.

Objective To evaluate the therapeutic effect of distal splenocaval shunt for portal hypertensive variceal rebleeding after periesophagastric devascularization.Method In this study 18 patients with recurrent bleeding after devascularization underwent distal splenocaval shunt.Clinical data and follow-up result were collected and analyzed.Result The free portal pressure decreased from (35.6 ±3.8) cm H2O before shunting to (26.9 ±2.7) cm H2O after shunting.The operative mortality was 0.Liver function after postoperative second day changed significantly comparing to preoperative levels and it recovered to pre-operative level after 7 days.The rate of rebleeding and ascites was 17％ and 44％ respectively.There were 2 patients suffering from postshunt hepatic encephalopathy and the 2-year survival rate was 94.4％.Conclusions Distal splenocaval shunt could still be performed in portal hypertensive patients with recurrent variceal bleeding after periesophagastric devascularization with a patent splenic vein.

Objective To explore the pathogenesis,diagnosis,therapy and prevention of portal vein thrombosis (PVT) after devascularization.Methods Data of 56 patients who underwent devascularization because of cirrhotic portal hypertension between Jan.2008 and Dec.2011 were retrospectively analyzed.Patients were divided into two groups according to whether or not to receive prophylactic anticoagulant therapy.There were 28 cases in each group.The causes of PVT was analyzed by Logit regression.Results Among all patients,9 patients developed PVT after operation (16％).The occurrence of PVT was 11％ in preventive anticoagulant treatment group,and that was 21％ in nonpreventive anticoagulant treatment group.Logit regression showed that there was no relationship in PVT with sex,age,preoperative platelet count and intraoperative ligation of splenic artery beforehand.There were apparent correlation in PVT with centrifugal-flow of portal vein and peak value of platelet count over ≥300 ×109/L.All patients discharged uneventfully after anticoagulant treatment.Conclusions The definite cause of PVT after devascularization is centrifugal-flow of portal vein and the peak value of platelet count over ≥300 × 109/L is a pivotal risk factor.The key point of therapy is early diagnosis and early anticoagulant treatment.

Objective To evaluate the operative safety of difficult splenectomy.Methods The clinical data of 126 splenectomy cases from January 2005 to December 2011 were analyzed retrospectively.Results All patients were cured and discharged.There was no mortality and pancreatic leakage,no gastric and colonic injury.The postoperative complications occurred in 14 patients including intra-abdominal hemorrhage in 5 cases,pulmonary complications in 7 cases (left pleural effusion and left subphrenic abscess),splenic venous thrombophlebitis in 11 cases and massive ascites in 10 patients.After splenectomy splenic and portal vein thrombi rate in HBV-related cirrhosis was 7％ (6/84) and that was 50％ (6/12) in schistosoma-related cirrhosis (t =13.4,P ＜ 0.01).Conclusions Careful evaluation before operation,skillful technique during operation are determinants for the safety of complex splenectomy.

The epidemic of severe acute respiratory syndrome(SARS) leads both to close cooperation and fierce competition in related researches globally. In March 2003, scientists from Hong Kong (China), America, Canada and German discovered a new type of coronavirus in SARS patients(SARS CoV) successively. And it was acknowledged by the WHO. Later, from April to May 2003, researchers from America, German, Chinese Hong Kong, Canada and Dutch published their findings about SARS pathogen in journals like Science, New England Journal of Medicine, The Lancet and Nature, etc . The gene map, complete genome sequence and molecular model of SARS CoV were reported, which has laid a sound foundation for SARS diagnosis, treatment and the development of vaccine. We can learn a lot from the rapid reaction of the related institutes, and the experience gained will benefit us in the future.

Based on the experience in combating severe acute respiratory syndrome(SARS) epidemic in Beijing, the paper analyzed the reasons for the SARS outbreak in Beijing and investigated the government reaction mechanism during emergency. The results showed that there were many defects in dealing with outburst of health event in the current system of public health for disease control, such as lack of the differentiation and prevention at the early stage, misconducts of the epidemic situation report system, lack of professional commanding system and the effective cooperation among the interrelated departments, weak team spirit,unconsciousness of intellectaul property right in the scientific research, and unreasonable medical resource allocation and storage system. Improvements concerning the above problems have been put forward to establish public health reaction mechanism for an emergent situation in China, providing contending for scholars and reference for the decision makers.

Targeted drug is becoming a hot point for anti-tumor research.The paper reviews the cate- gory,speciality,principle of action and clinical application.The review also focus on the advance of anti-tu- mor targeted drug and forsee the prospect of it.

The surgical treatment for portal hypertension (PHT) aims to control and prevent the gastroesophageal variceal bleeding.The choices of surgical timing and procedures are dependent on the liver reserve function.Except for Child-Pugh classification and model for end-stage liver disease scoring system,the future liver remrant and pre-albumin are the important evaluation indexes,meanwhile,the choice of surgical procedures would be dependent on portal hemodynamics that can reduce incidence of rebleeding of postoperative hepatic encephalopathy.Hepatic venous pressure gradient is the most important objective index forecasting bleeding risk and severity of PHT.

Objective To study the inhibitory effect of yan xiao capsules on hepatocarcinoma mice. Methods Forty mice were randomly divided into control group ,CTX group,ADM group,trial group. Observe tumour weight ,the span time of tumour-bearing mice, tumour morphology and the mortality rate of ascites cancer cell by direct killing respectively. Results The tumour weight markedly decreased in trial group, the rate of inhibition tumour was 52.0 %(P