Objective To investigate the effects, and possible mechanism of action, of vasoactive intestinal peptide (VIP) on acute lung injury in a rodent model of endotoxic shock. Method Endotoxic shock was induced in Sprague-Dawley (SD) rats by intravenous injection of lipopolysacchaiide (LPS) at 10 mg/kg. Three groups (each group with 10 rats), were given injections of either normal saline (Control), LPS 10 mg/kg (LPS group), or LPS 10 mg/kg + VIP 5nmol (VIP). Samples were collected 6 hours after injection. Indices of lung injury including lung wet/dry weight ratio, protein concentration and neutrophil count in bronchoalveolar lavage fluid( BALF) were derived. Assays of TNF-α,IL-1β, IL-10 in serum and BALF were performed using ELISA. Light and electron microscopy were used to detect histopathological changes in lung tissues. Results The lung wet/dry weight ratio, protein concentration and neutrophil count in BALF were significantly raised in the LPS group compared to the Control group (P ＜ 0.05). These indices were significantly lowered in the VIP group compared to the LPS group, though not to the level of the control group. Concentrations of TNF-α, IL-1β, IL-10 in serum and BLAF also increased in the LPS group compared to the control group (P ＜ 0.0S). Levels of TNF-α and IL-1β were significantly lowered in the VTP group compared to the LPS group (P ＜ 0.05), while levels of IL-10 was significantly raised ( P ＜ 0.05). Histopathological changes due to lung injury were not as severe in the VIP group compared to the LPS group. CondusKms VIP plays a protective role during acute lung injury induced by endotoxic shock in rats. Its mechanism of action may be related to down-regulation of proinflammatory cytokines and up-regulation of anti inflammatory cytokines.

Objective The aim of this study was to establish a reasonable protocol for a rat model of ferric chloride-induced carotid arterial thrombosis by ultrasonic continuous evaluation.Methods Twenty SD rats were randomly divided into four groups and then treated with 20％,30％,40％ or 50％ concentrations of FeCl3,respectively.The vascular conditions were evaluated by 14L ultrasonic probe,at 10 mins,15 mins,and 20 mins.We then selected the best group through the examination of the rate of spontaneous reperfusion of blood vessels and the rate of reperfusion after intravenous injection of urokinase.At the end of the experiment,vessels were fixed in 10％ formalin solution and stained with HE.Results After external application of FeCl3 on rat common carotid artery for 20 mins,the artery occlusion rate was 100％,20％,0％ and 0％ in animals receiving 50％,40％,30％ and 20％ FeCl3,respectively.After external application of FeCl3 on rat common carotid artery for 120 mins,the spontaneous revascularization rate was 0％ in 50％ concentration group whereas were 100％ in rest other groups (P＜ 0.001).In 50％ concentration group,the partial recanalization rate was 40％ after intravenous injection of urokinase.HE staining revealed that the thrombus was dense and the lumen was partially recanalized after the urokinase intervention in 50％ concentration group.Conclusion By use of uultrasonic continuous evaluation of ferric chloride-induced thrombosis of rat common carotid artery,we have demonstrated that external application of 50％ ferric chloride solution for 20 mins is effective for the formation of thrombus model,which may be suitable for the studv of thrombolysis.

BACKGROUND: At present, the materials that are successful y applied in rib fracture internal fixation mainly include titanium, nitinol rib encircling bone bonding plate, imported poly-L-lactic acid absorbable rib nails and anatomical plate.
OBJECTIVE: To study the biomechanical characteristics of new magnesium al oy absorbable rib intramedul ary nail in the rib fracture fixation, and to compare with imported poly-L-lactic acid absorbable rib intramedul ary nail in order to provide scientific basis for clinical application.
METHODS: Thirty fresh adult fifth rib specimens were col ected, and the specimens were used to make models for the middle rib fractures. The specimens were fixed with AZ31B magnesium al oy absorbable rib intramedul ary nail (magnesium al oy group) and poly-L-lactic acid absorbable rib intramedul ary nail (poly-L-lactic acid group), and the normal rib specimen group was set as control. The biomechanical characteristics of the nails in each group were tested with stress analysis.
RESULTS AND CONCLUSION: Three-point bending strength measurement results showed that the bending strength in the magnesium alloy group was close to the normal value of the specimen (P > 0.05), and there was significant difference in the bending strength between magnesium alloy group and the poly-L-lactic acid group (P < 0.05). Torsional strength measurement showed that there was no significant difference in torsional strength between magnesium alloy group and the normal specimens, and the results showed that the magnesium alloy was better than poly-L-lactic acid in fixation (P < 0.05). Tensile tests showed that the tensile strength and anti-pulling force of the magnesium alloy fixation were better than those of poly-L-lactic acid fixation (P < 0.05). The results indicate that the magnesium alloy absorbable rib intramedullary nail is better than poly-L-lactic acid absorbable rib intramedullary nail in strength and tensile strength, which is the ideal fixation material for rib fixation.

Objective To study the type and corresponding clinical characteristics of primary hemophagocytic lymphohistocytosis (HLH) associated immune gene mutations in the refractory virus infection or HLH of unknown causes. Methods From December 2009 to July 2010, the patients with refractory virus infection or HLH of unknown causes were screened for the primary HLH associated immune genes mutations by DNA sequence analysis, including PRF1, UNC13D, STX11, STXBP2, SH2D1A and XIAP. The clinical characteristics and outcomes were followed up. Results Totally 25 patients with refractory virus infection or HLH of unknown causes were investigated for the 6 genes and 13 cases were found carrying gene mutations, composing of 6 of PRF1 mutation, 3 of UNC13D, and each one of STX11,XIAP, SH2D1A and STXBP2, respectively. Among the 13 cases with gene mutations, 5 suffered from Epstein-Barr virus associated HLH( EBV-HLH), 1 human herpes virus 7 associated HLH (HHV7-HLH),1 HLH without causes, 4 chronic activated EB virus infection (CAEBV) with 1 progressing to Hodgkin's lymphoma carrying abnormal chromosome of t ( 15; 17 ) (q22; q25 ) and hyperdiploid, 2 EBV associated lymphoma. Among the other 12 patients without gene mutation, 4 suffered from EBV-HLH with 1 progressing to peripheral T lymphoma, 8 suffered from CAEBV. Conclusions Primary HLH associated immune gene mutations are critical causes of refractory virus infection of unknown causes, most patients manifest as HLH,some cases appear in CAEBV and EBV associated lymphoma. DNA sequence analysis is helpful to early diagnosis and correct decision-making for treatment.

Medical education reform mainly focused on the reform of the form and method of teaching but neglected the reform of the teaching concept that has truly penetrated into all aspects of teaching. With reference to the reflection on the teaching goal of physiology and the need of the cultivation of "post competency", the core concepts of physiological teaching are summarized into the following four aspects: "Three Outlooks" must be positive to help students establish a balanced view, a dialectical view, and a holistic view; "Three Fundamentals" should be solid to help students master basic knowledge structure system, cultivate basic knowledge acquisition ability, and improve basic operation skills; students should attach importance to learning and use; humanistic quality should be strengthened. The above core concepts have been widely recognized by students in teaching practice, and clinical medical students have significantly better evaluation of the core concepts than nursing students. Future direction of the subsequent teaching reform should be how to refine the contents of lectures under the guidance of the teaching concepts to adapt to the increasingly detailed specialities.

To investigate the correlation between plasma D-dimer and subtype，severity and functional prognosis of patients with acute ischemic stroke. Methods The clinical，imaging and laboratory data of patients with acute ischemic stroke were confirmed by clinical and imaging in Peking Union Medical College Hospital from January 2013 to December 2020 were analyzed retrospectively. Results There were 1034 patients with acute ischemic stroke confirmed by clinical and imaging，of which 845 patients completed the detection of plasma D-dimer level within 24 hours and were included in this study. Plasma D-dimer levels was significantly different in different stroke subtypes （P<0.001）. Plasma D-dimer levels was positively correlated with NIHSS score （r=0.166，P<0.001） and mRS score （r=0.125，P<0.001）. Binary regression analysis showed that plasma D-dimer level was associated with poor functional prognosis （unadjusted OR=1.058，95%CI 1.019～1.099；adjusted model 1 OR=1.026，95%CI 1.014～1.091；adjusted model 2 OR=1.022，95%CI 0.984～1.061）. NIHSS score played a full mediation effect between plasma D-dimer level and poor functional prognosis. The sensitivity of plasma D-dimer levels in predicting the prognosis of poor functional prognosis was 54.9%，the specificity was 66.1%，and the area under the receiver operating characteristic （ROC） curve was 0.609.Conclusion We had shown that plasma D-dimer levels are significantly correlated with the etiological classification and severity of acute ischemic stroke，and plasma D-dimer levels may affect the functional prognosis through this correlation. In addition，plasma D-dimer levels can be used to predict poor functional prognosis of acute ischemic stroke.