BACKGROUND: Simply used natural materials-prepared scaffolds such as collagen, gelatin and fibrin solve problems of biocompatibility, but its degradation is rapid, and cannot induce new tissues, but collapse is found as cell scaffolds.OBJECTIVE: To explore and determine the property of biological degradable three-dimensional porous scaffolds using silk fibroin-chitosan composite.DESIGN, TIME AND SETTING: The material observational study was performed at the Institute of Bioengineering, Zhejiang Academy of Medical Science from June 2008 to June 2009.MATERIALS: Spring silk cocoon was presented by a silkworm farmer from Huangdunmiao village, Maqiao town, Haining City,Zhejiang Province, China. Chitosan was produced by Shanghai Bo'ao Biological Technology.METHODS: 15 g/L silk fibroin solution was made by degumming, salvation and dialysis. Chitosan was dissolved in 2% acetic acid solution to prepare 25 g/L chitosan-acetic acid solution. Two solutions were mixed to prepare six silk fibroin/chitosan solutions, and mass ratio was 10: 0, 5: 5, 4: 6, 3: 7, 2: 8, 0:10. These solutions were separately sucked in a 24-well plate. Following exhausting gas vacuole at 4 ℃, precooling was performed at -20 ℃ for 12 hours, followed by cryodesiccate for 30 hours. Samples were then hydrated in ethanol, neutralized in NaOH-alcohol for 1 hour, washed and then frozen to dry.MAIN OUTCOME MEASURES: Optical microscope and scanning electron microscope were used to observe pore size and structure of various mass ratio-prepared scaffold. Modified liquid substitution method was utilized to measure porosity of various scaffolds. The degradable rate of various scaffolds was determined at 4 weeks in vitro.RESULTS: Silk fibroin/chitosan of 10: 0 mass ratio-prepared scaffold had rough fluffy pore, was brittle, with high dissolve-loss rates. On the contrary, chitosan-prepared scaffold was hard, without enough elasticity following freeze-dry. The composite scaffold of 5: 5, 4: 6, 3: 7 and 2: 8 following freeze-dry was loose and soft, similar to sponge. With increased chitosan concentration,scaffold hardness increased. There were evenly distributed, detailed eyelets on the scaffold. Under the optical microscope,various pores were irregular; each pore closely connected and linked together; pore size was even, 20-100 μm. With increased chitosan concentration, pore size was gradually reduced. Scaffold porosity determination results displayed that mass ratio of silk fibroin/chitosan 4: 6 group > 5: 5 group > 3: 7 group > 2: 8 group. Compared with 2: 8 group, the porosity was significantly increased in the 5: 5 and 4: 6 groups (P < 0.05). No significant difference was detected in volume expansibility in the silk fibroin/chitosan composite scaffold of various mass ratios (P > 0.05). The degradation was slowest in the 2: 8 group, and fastest in the 5: 5 group at 4 weeks.CONCLUSION: Regarding physical and chemical properties, composite scaffold made by silk fibroin/chitosan showed significant superiority compared with scaffold made by silk fibroin or chitosan alone. Of them, silk fibroin/chitosan mass ratio of 5: 5 and 4: 6 are accorded with the requirement of cartilage tissue engineering.

OBJECTIVE: To prepare chitosan microspheres encapsulated transforming growth factor β1 (TGFβ1), and to analyze its property. METHODS: The chitosan was dissolved in 2% acetic acid to prepare chitosan microspheres encapsulated TGFβ1 with emulsification cross-linking method, Tween 80 and sodium polyphosphate were served as emulsifying agent and cross-linking agent, respectively. Meanwhile, chitosan microspheres and containing bovine serum albumin chitosan microspheres were prepared as blank control and experimental control groups. The morphology and diameter of 3 kinds of microspheres were observed, and the dispersion and in vitro release of chitosan microspheres encapsulated TGFβ1 were detected, furthermore, the water absorption expansion rate of blank control and experimental control groups were measured. RESULTS: Scanning electron microscopy showed that the microspheres diameter in the blank group was approach 15 μm, with smooth surface and plenty of tiny pores. However, the microspheres in the other 2 groups were distributed uniformly with approximately 1 μm in diameter, the surface was smooth. The chitosan microspheres encapsulated TGFβ1 released fast at begin 12 hours, and then gentled gradually, with 53.5% release ratio within 6 days. The increased mass of microspheres in the blank control and experimental control groups reached a balance after 1 hour, both of which were over 700%,in particular larger in the acid environment. CONCLUSION: Chitosan microspheres encapsulated TGFβ1 prepared by emulsification cross-linking method exhibit high yield and good drug release. The strong water absorption expansion rate of chitosan microspheres requires aperture size, as well as intensity of bone tissue engineered scaffold.

Objective To study on the activity of intestinal mucosal mast cells (IMMC) in dextran sulfate sodium ( DSS) induced colitis of rats. Methods Acute colitis was induced by giving 3% DSS orally. Eighteen male rats were randomized into DSS group ( n = 10 ) and normal control group ( n = 8). The rats in DSS control group drank 3% DSS solution from day 1 to day 7; those in normal control group drank water at random. Diarrhea and bloody stool as well as colonic histology were observed. The levels of colonic tissue histamine, tumor necrosis factor-a (TNF-a) and Prostaglandin E2 ( PGE2) determined with fluorimetry and ELISA, and the expression of IMMC in colonic tissue was detected by histochemical stain method. Results Compared with normal control group, the inflammatory symptoms and histologjcal damages of colonic mucosa in DSS group were significantly presented. The level of histamine in colonic tissue was significantly reduced (P

Objective To investigate the value of prevention of cerebral ischemia with multi-modality neuroelectrophysiological monitoring in intracranial aneurysm embolization. Methods The clinical data of 44 patients with intracranial aneurysm treated with endovascular embolization from May 2013 to June 2014 were analyzed retrospectively. The patients were divided into two groups according to whether they used intraoperative neuroelectrophysiological monitoring. There were 21 patients in a monitoring group and 21 in a non-monitoring group. According to the site of the aneurysms,somatosensory evoked potential ( SEP),motion evoked potential( MEP),scalp electroencephalogram,and brainstem auditory evoked potential (BAEP)were monitored,and at one day after procedure,their newly developed neurological deficits and the follow up observation after 3 months in both groups were compared and analyzed. Results The intraoperative SEP,MEP,and scalp EEG changes in the monitoring group were observed in 9,3 and 4 patients,respectively. Timely preventive measures were taken for 9 of the patients with cerebral ischemia revealed by neuroelectro-physiological monitoring. At the first day after procedure,the incidence of patients with new neurological deficit was 17. 4%(4/23)in the monitoring group,and that was 47. 6%(10/21)in the non-monitoring group. There was significant difference between the 2 groups(χ2 =4. 623;P<0. 05). There was significant difference in the good prognosis rates(87. 0%[20/23]vs. 57. 1%[12/21])after 3-month follow-up (χ2 =4. 919;P<0. 05)between the 2 groups. There were no deaths in both groups. Conclusion Multimode in combination with neuroelectrophysiological monitoring may decrease ischemic complications in aneurysm interventional treatment and improve the safety of procedure.

[Summary] With populational proportional sampling (PPS) method in Baiguo village,one central primary sehool was selected,and villagers aged 20-80 in nearly village were chosen as control.Cross-seetional survey methodology was employed,B-type ultrasonography was used to determine thyroid volume and nodule of ebildren.Arsenic cerium catalytic spectrophotonetric assay was employed to detect urinary iodine.A direct titration measurement was used to determinate iodine content in salt.180 children aged 6-12 were surveyed,2 cases of goiter were found (1.11％).16 cases of thyroid nodules were discovered(8.89％),including 3 boys(3.45％,n =87) and 13 girls(13.98％,n =93).Girls had a higher prevalence than boys (x2 =6.154,P =0.015).The prevalence of thyroid nodules in that village was 24.51％,being statistically significant between 2 groups (x2 =17.368,P =0.001),and increasing with the age.

Attentions have been paid to teaching Nepal students in English in our university,and many problems need to be analyzed and solved.Selection and application of appropriate teaching material,sufficient preparation before class and applying nimble teaching style have received satisfactory results.

Objective To investigate the correlation of rCBV with vascular endothelial growth factor (VEGF) protein expression and microvessel density (MVD) in gliomas Methods MR examinations were performed preoperatively in 46 patients with suspected supratentorial gliomas All the 46 cases were proved by operation and pathology Immunohistochemical stain methods were used to demonstrate the situation of VEGF protein expression and quantitatively measure the MVD in gliomas The procedures of MR examinations included plain MR scan, PWI and routine contrast enhanced MR scan The pulse sequence of PWI was single shot GRE EPI T  2WI The CBV maps were calculated from the original data of perfusion images and the maximum rCBV of gliomas was acquired from CBV maps through measurement on the region of interest (ROI) According to the situation of VEGF protein expression, all the 46 cases were divided into two groupsincluding positive VEGF protein expression group and negative VEGF protein expression group Mann Whitney U test was used for comparing the difference between the two groups Spearman′s rho correlation analysis was used for observing the correlation between maximum rCBV and MVD in gliomas Results Of the 46 cases; 12 cases were astrocytomas, 3 were oligodendrogliomas, 1 was mixed glioma, 14 were anaplastic astrocytomas, and 16 were glioblastomas multiforme The maximum rCBV value in VEGF(-) group ( n =14) and VEGF(+) group ( n =32) ranged from 0 33～6 63 and 1 03～10 68, with median of 3 08 and 5 95, respectively The difference in maximum rCBV between the two groups was statistically significant ( Mann Whitney U test | z| =2 638, P

BACKGROUND:Sensitivity of diagnoses differentiating smaller nodes of splenic metastasis (＜ 1 cm) from CT and MRI is poor. So whether superparamagnetic iron oxide can enhance magnetic resonance imaging (MRI) of splenic VX2 tumor in rats need to be further studied.OBJECTTVE: To establish splenic VX2 tumor models, investigate MRI scanning combining with superparamagnetic iron oxide of specific reticuloendothelial system, and study the diagnostic significance of superparamagnetic iron oxide-enhanced MR images on splenic metastases.DESIGN: Duplicated-measured animal study.SETTING: Medical Imaging Center, Nanfang Hospital of the Southern Medical University.MATERIALS: The experiment was carried out in the Medical Imaging Center (Military Key Laboratory), Nanfang Hospital of the Southern Medical University from May 2005 to March 2006. A total of 25 adult SD rats, of either gender, weighing 200-300 g, were selected in this study. The animal experiment had got confirmed consent from local ethic committee. All rats were randomly divided into tumor group (n =20) and blank control group (n =5).METHODS: Models of VX2 tumor in spleen were established successfully. The images obtained before and after administration of superparamagnetic iron oxide. T1-weighted image(T1WI) (450/12 ms) and T2-weighted image(T2WI)(4 000/128 ms) were used to scan sequences. The imaging parameters of various tissues were analyzed before and after superparamagnetic iron oxide-enhanced MRI scanning. Rats in the blank control group were not used to establish models and the sequences were scanned as the same as those in the experimental group.MAIN OUTCOME MEASURES: Signal characteristics of various tissues before and after before and after superparamagnetic iron oxide-enhanced MRI scanning.RESULTS: Eight out of 20 rats died in the tumor group and other 12 and 5 rats in the control group were involved in the final analysis. MR scanning indicated that 8 rats in the tumor group had splenic VX2 tumor. ① On plain MR scanning T1-weighted splenic VX2 tumor showed hypointensity or isointensity which approximated to the signal intensity (SI) of splenic parenchyma. All lesions had been not displayed well. ② On superparamagnetic iron oxide enhancement T2WI sequence the SI of splenic parachyma decreased obviously with percentage of signal intensity loss (PSIL) was 56.11%,But the SI of tumor was not evidently change with PSlL was 1.90%. Nevertheless the signal-to-noise ratio (SNR) of normal splenic parenchyma around the lesions had obviously difference (P ＜ 0.001) comparatively. So the contrast between tumor and spleen increased, and tumor displayed more clear. Moreover the contrast-to-noise (CNR) between VX2 tumor and splenic parenchyma had an evidently difference with before and after admininstration of superparamagnetic iron oxide (P ＜ 0.001 ).CONCLUSION: On superparamagnetic iron oxide enhancement T1WI sequence the contrast of tumor-to-spleen is poor.So it is not good to characterize the lesions in spleen. On superparamagnetic iron oxide enhanced T2WI the contrast degree of lesions increased obviously. Consequently, superparamagnetic iron oxide-enhanced T2WI MRI scanning can improve the rate of detection and characterization in lesions of spleen.