A theoretical model for the magnetic forces on ferromagnetic drug particles in a guiding magnetic field is established with the consideration of the electromagnetic field theory. Our model shows that the ferromagnetic drug particles can concentrate on the targeted area with the guidance of the outside magnetic field. Both the distribution of the intensity of the guiding magnetic field and the forces on ferromagnetic drug particles are studied numerically. The theoretical results are in good agreement with the experimental results reported recently.

Objective To evaluate the double-balloon enteroscopy(DBE) for obscure gastrointestinal bleeding(OGIB) and evaluate the health economics under the guidance of DBE for surgical treatment of obscure gastrointestinal bleeding.Methods A total of 114 patients,whose hemorrhage etiology could not be determined by conventional gastroscopy,enteroscopy and gastroenterography,underwent DBE.With pathological results as diagnostic criteria,the value of double-balloon enteroscopy for obscure gastrointestinal bleeding diagnosis was studied.Results The sensitivity,specificity and accuracy of DBE for OGIB were 85.86％,63.63％,81.57％,respectively.The positive likelihood ratio was 2.36 and the negative likelihood ratio was 0.22.The total days of hospitalization,hospital costs,cost of hospital drugs were lower in the DBE group than in the control group(27.2 ± 11.8 days VS 16.4 ±5.3 days,35 690.2 ±3 466.5 Yuan VS 19 409.3 ± 9 253.2 Yuan,17 805.8 ± 2 145.5 Yuan VS 9 133.0 ± 4 664.9 Yuan) (all P ＜ 0.05).Conclusion DBE plays an important role in diagnosis of OGIB.It has significance in clinic,health economics,and social benefits.

Objective To study the relevant factors of malignant change of colorectal adenoma. Methods The clinical data of 276 cases of colorectal adenoma admitted in our hospital in recent 14 years were analyzed retrospectively . Results Malignant change rate of the adenoma in the left colon was significantly higher than that in right colon(P

Objective To assess the relationship between auditory evoked potential (AAI) index and plasma concentration of propofol administered by target-controlled infusion (TCI) in Chinese.Methods Ten ASA Ⅰ～Ⅱ tumor patients (5 males,5 females) scheduled for elective abdominal surgery under general anesthesia was enrolled in this study.Age ranged from 34 to 61 years,body weight from 52 to 79 kg and height from 155 to 178 cm.Radial artery was cannulated for blood sampling.The patients were premeditated with intravenous injection Midazolam 0.06 mg/L.Anesthesia was induced by fentanyl 2μg/kg,vecuronium 0.1 mg/kg and TCI of propofol which the target plasm concentration was set at 3 mg/L.After intubation,the target plasma concentration of propofol was adjusted at 1.7～2.5 mg/L.Vecuronium was continuous infusions at 2～3mg/h.Anesthesia was maintained with fentanyl-TCI of propofol-vecuronium and inhalation of 0.5 MAC isoflurane.The TCI system was composed of Base Primea company orchestra infusion pump using,the schnider pharmacokinetics model.ECG,Bp,HR,PETCO2,SpO2 and TETISO were monitored during anesthesia.Danmeter company A-line depth of anesthesia monitor recorded AAI index.Blood samples were taken at induction of anesthesia (To baseline),1,3,5,10,15,30,60 min (T1-7) and after cessation of infusion 10 and 20 min (T9-10).Plasma propofol concentration were determinated by fluorescence photometry.Results Compared with target concentrations,the measured concentrations of propofol were significantly lower during TCI(P＜0.05).There was negative correlation between AAI and plasma propofol concentrations(r=-0.818,P＜0.01).Conclusion On base of the Schnider pharmacokinetics model,the target propofol concentrations are not paralleled to plasma propofol concentrations which is descending with time prolongation.From negative correlation between AAI index and plasma propofol concentrations,AAI index will reflect indirectly plasma propofol concentrations.

Objective To study the effects of 2,2',4,4'-tetrabromodiphenyl ethers(PBDE-47)single exposed and combined with 2,2',4,4',5,5'-hexachlorobiphenyl(PCB153)on learning and memory ability and the uhrastrncture of hippocampal CA1 region in rats.Methods Neonatal SD rats(CL grade)were randomly divided into groups,9 male and 9 female in each,then were exposed to single PBDE-47 at doses of 1,5,10 mg/kg and combined with PCB153 at dose of 5 mg/kg,through gavage for one time. Soya oil was used as the solvent control.The learning and memory ability and ultrastructure of neurons in hippocampal CA1 region were examined respectively 2 months after treatment.Results In the low dose groups(1 mg/kg PBDE-47 and 1 mg/kg PBDE-47+ 5 mg/kg PCB153 treated group),the ultrastructure of neurons in hippocampal CA1 region were as normal as that in the control group.As the dose increasing,in 5 mg/kg PBDE-47 group,the endoplasmic reticulum appeared swelling,expansion and degranulation.In 5 mg/kg PBDE-47 plus 5 mg/kg PCB153 group,the mitochondria appeared swelling,the ridge ruptured,the periplast puffed,and then the cytoplasm condensed.In the high dose groups(10 mg/kg PBDE-47 group and 10 mg/kg PBDE-47 plus 5 mg/kg PCB153 group),the neurons showed acutely denatured,the periplast puffed,the cell organelle dissolved and the mitochondria vacuolizated.The interaction between PBDE-47 and PCB153 on the latency period and the general pathway was presented in place navigation test(P

In the reform of medical microbiology education on medical students of 8-year-education pro-gram, we compared the traditional teaching methods with Problem Based Learning (PBL) method. Through our practice, we have found that the combination of traditional lecture-based learning and PBL seems to better match the students’ way of learning. The lack of basic knowledge of the students hindered their learn-ing effect during the bilateral discussion in the PBL education. We also found that the application of PBL in medical microbiology education is an iterative process and should be promoted step by step. The theoretical level and the innovative ideas of the teachers play a crucial role in the dynamic process of education reform.

Objective To explore the effect of Fas/FasL pathway on fluoride.induced apoptosis in hurnan neumbla8toma SH-SY5Y cells.Methods The cell survival rate,percentage of apoptosis,and mRNA expression levels of Fas and FasL were measured respectively after the SH-SY5Y cells were exposed to O(control),20,40,80 mg/L sodium nuoride(NaF)for 24 hours/n vitro.Furthermore,the changes of the percentage of apoptosis and mRNA expression levels of Fas and FasL in 40 mg/L NaF-treated groups incubated with activaling or neutralizing anti-Fas antibody(CH11 or ZB4)also observed respectively.Results Compared with the control group(100.00%), the cell surval rates in 40,80 mg/L NaF-treated groups[(84.63±2.57)%,(69.04±5.63)%]were significandy lower(P<0.01).The percentage of apoptosis in 40,80 mg/L NaF.treated groups[(8.54±1.95)%.(17.94±2.71)%]were higher(P<0.05)than thal in the control group[(3.32±1.33)%],and increased with the dose of NaF.NaF could up-regulate Fas and FasL mRNA expression,and increased the Fas/β-actin [40 ms/L group (0.94±0.51),80 mg/L group(0.99±0.12)]and FasL/β-actin[40 mg/L group(0.96±0.42),80 mg/L group(0.99±0.24)] ratio,compared with the control[Eas/β-actin(0.50±0.33),FasL/β-actin(0.58±0.23)],both the difference had 8tatistical significances (P<0.05).NaF and CH I 1 had a synergisfic effect on apoptosis and mRNA expression levels of Fas and FasLL(F=32.89,18.46,.14.69,P<0.01)while NaF and ZB4 had an antagonistic effect (F=5.73,24.26,10.17,P<0.05 or<0.01).Conclusion NaF exposure can cause apoptosis in SH-Y5Y cells,and the Fas/FasL pmhway may play an important role in NaF-induced apoptosis.

Objective To investigate the dynamic changes of serum insulin-like growth factor-1 (IGF-1) in acute traumatic brain injury (TBI) as well as their correlations with the initial severity of TBI and prognosis.Methods A total of 229 patients with acute TBI admitted from September 2014 to June 2016 were retrospectively studied.Patients were further classified as mild TBI group (GCS 13-15 points),moderate TBI group (GCS 9-12 points) and severe TBI group (GCS 3-8 points) according to Glasgow coma score (GCS).The control group consisted of 30 healthy subjects.The prognosis was evaluated by using Glasgow outcome scale (GOS) at 6 months after TBI.The IGF-1 levels were further tested at days 1,3,5,7 and 14 and their correlations with the initial GCS and GOS at 6 months after injury were evaluated.Results (1) The serum IGF-1 levels of mild,moderate and severe TBI group at all time points were significantly lower than those of the control group (P ＜ 0.05);the serum IGF-1 levels of severe and moderate TBI groups at all time points after injury were significantly lower than those of the mild TBI group (P ＜0.05);the serum IGF-1 levels of the severe group at days 1,3,5 and 7 d after injury were lower than those of the moderate TBI group (P＜0.05).(2) IGF-1 levels were significantly different between the two groups (P ＜ 0.05) at different time points during the follow-up of 6 months.(3)IGF-1 levels were positively correlated with both GCS and GOS at the acute stage of TBI and sub-acute stage following TBI (P ＜ 0.05).Conclusion The dynamic changes of serum IGF-1 levels in patients with acute TBI are related to both initial severity of TBI and the neurological outcomes and can be used as a reliable biomarker for early severity assessment and prognostic prediction of TBI.

Objective To investigate the mechanisms of phagocytosis of virulent Leptospira by peritoneal macrophages of guinea pigs,andevaluatetheroleof innateimmuneinthepathogenesisof leptospirosis. Methods Peritoneal macrophages of guinea pigs were extracted. Three specific inhibitors ( microfilament inhibitor cytochalasin D,microtube inhibitor colchicine and PI3K signalling pathway inhibitor LY294002) were added respectively to the macrophages 1 h before the infection of virulent Leptospira interrogans serovar Lai type strain Lai in vitro.Meanwhile, control group without inhibitor was established.Phagocytosis was observed by laser scanning confocal microscopy and phagocytic rates were evaluated by flow cytometry 3 h after infection.ResultsThe phagocytic rates of control group, cytochalasin D group, colchicine group and LY294002 group were (38.98 ± 0.91)%,(23. 99 ± 1. 40) % ,(40.81±0.91)% and (39.64 ±3.56) %, respectively.The phagocytic rate of cytochalasin D group was significantly lower than that of control group (P < 0. 05), while those of colchicine group and LY294002 group were not significantly different from that of control group (P >0.05). ConclusionMicrofilaments play an important role in the phagocytosis of strain Lai by peritoneal macrophages,but the process is independent on PI3K signalling pathway,and microtubes play little part during the phagocytosis.

Objective To evaluate the diagnostic value of MSCT in Solitary Pulmonary Nodules (SPN) with different pathologic types .Methods Four-five SPN with pathological findings including 16 benign cases and 29 malignant cases were retrospectively an-alyzed ,and performed with MSCT scanning .Observation of the distribution ,morphology and internal characteristics of SPN by post-processing technique were done ,and the results were compared with pathological findings .Results Among 45 SPN ,the benign nodules included 6 cases of inflammatory pseudotumor ,4 cases of tuberculoma ,3 cases of hamartoma ,2 cases of cryptococcus and 1 case of hemangioendothelioma ,and the malignant nodules included 21 cases of adenocarcinoma ,3 cases of squamous carcinoma ,2 ca-ses of small cell carcinoma and 3 cases of alveolar cell carcinoma .Average diameter of benign nodules was 2 .1 cm ,and 2 .6 cm for the malignant nodules .All SPN ,including 5 cases in the inner zone ,12 in the medial zone and 28 in the lateral zone ,the percentages with malignant signs at the corresponding parts were 40% (2/5) ,50% (6/12) ,75% (21/28) ,there was significant difference be-tween distributions(P<0 .05) .The distributions of malignant nodules in the upper and lower lung lobe had no significant difference (P>0 .05);the incidences of leaf sign ,burr sign ,pleural indentation sign ,cavitas and bronchial air sign ,blood vessels cluster sign of malignant nodules were higher than that of the benign nodules(P<0 .05) ,and the inflammatory pseudotumor and adenocarcinoma owned similar characteristics ;the incidence of calcification in tuberculoma and hamartoma was high ,while cavitas in tuberculosis and lung cancer were high .Conclusion MSCT can sufficiently display the distribution ,morphology and internal characteristics of SPN , and can help make qualitative diagnosis of benign and malignant SPN ,providing great practical value in clinical treatment .