Objective To study the effects of cryopreservation and two different cooling rates on rat hepatocytes. Methods Perfusion with collagenase digestion was used to isolate rat hepatocytes. Hepatocytes were incubated with a freezing medium consisting of RPMI 1640 with 20% calf serum and 10% DMSO. Two different freezing protocols were applied using a computer controlled freezer to freeze the medium to -80℃ before hepatocytes were plunged into liquid nitrogen and stored. The viability, morphology, and protein synthesis were measured at Day 3, Day 15, Day 30, respectively after thawing. Results Both viability and protein synthesis ability of group B and group C decreased significantly as compared with that of Group A ( P 0.05). Electron microscopy showed ultrastructural changes between fresh and thawed rat hepatocytes including injury of cell membrane, loss of cell content, alteration of nucleolus. The degree of injury in Group B is slighter than in Group C. Conclusion Cooling rate of cryopreservation correlates with the quality of thawed hepatocytes. The cryopreservation and thawing procedures are key factors to affect the quantity and quality of hepatocytes. The viability and protein synthesis ability are not influenced by the storage period in liquid nitrogen.

Objective To investigate and analyze the characteristics and stratified influencing factors of self-directed learning of nursing college students.Methods In November 2016,a total of 304 students from three nursing colleges in Sichuan province were investigated with self-rating scale of self-directedness learning (SRSSDL).304 copies of the questionnaires were issued and recovered.Using SPSS 13.0,the independent sample t test and variance analysis were used to compare the differences between groups.Pearson correlation test and multiple linear regression were used to analyze the influencing factors.Results The average SRSSDL score of key undergraduate students of nursing college was (220.27 ± 30.16),the score of general undergraduate students was (212.37 ± 25.01),the score of Junior college students was (205.26 ± 29.84),The score difference has statistical significance (F=6.191,P=0.002).Students from key undergraduate had the highest self-directed learning ability,and students from general undergraduate and Junior college had the medium self-directed learning ability.The factors such as different levels,whether the one-child,self-study time every day,team learning experience affect students' self-directed learning ability.Conclusions We should create conditions for students to study independently,cultivate professional identity and independent spirit under the premise of clear educational objectives to improve their SDL ability.

Objective To examine the white matter micro structural changes of hippocampus in the mid-die-aged major depression, and hypothesis that the hippocampal neurogenesis during the effective antidepressants can be found by diffusion tensor imaging(DTI) technology. Methods Middle-aged patients with major depression were enrolled, twenty patients received open but controlled with SSRIs for 10 weeks,twenty age, gender, education-matched healthy controls were involved as control group. All the subjects were scanned by DTI,using both whole-brain,voxel-based analysis(VBA) and Regions of interests (ROIs) methods to analyze the data. Results The VBA analysis found the post treatment patients made significant improvement in the fight inferior frontal lobe, left cingulate gyms of iimbic lobe and the right sub-gyral of occipital,but no significant difference in the hippocampus were found between any groups (all P<0.01, cluster>20). For the hippocampal relative FA of ROIs analysis,there were no significant difference between the patients before and after treatment, even no difference between the prior-treatment patients and healthy control,the remitted patients and the healthy controls(P<0.05). Conclusions Micro structural white matter changes in the frontal gyms, temporal and cingulated gyms are associated with mid-die-aged depression,no changes were found in the hippocampus. These findings do not support the hypothesis that the hippocampal neurogenesis can be found by DTI technology.

Objective To explore the feasibility and value of treating esophageal thoracic fistula with covered esophageal stent through nasal esophagus drainage tube. Methods Seven patients with esophageal thoracic cavity fistula were enrolled and treated by 5F pigtail side-holes catheter inserting into thoracic cavity for drainage and then again through nasal esophagus and fistula, placing a covered stent in the esophagus to occlude the orifice of the fistula. The abscess cavities were washed and radiographied periodically through drainage tubes. Results The insertion of the drainage tube and the placement of covered stent were all successful. The drainage tubes were placed in abscess cavities for 12-22 days, average 15 days. The radiography through drainage tubes showed that the abscess cavities disappeared or shrank obviously with control of hydropneumothorax before the drainage tubes being pulled out. The esophagogram after withdrawal of the drainage tubes notified that the fistulae were occluded satisfactorily with stents expanded fully without displacement and stenosis. Conclusions Treating esophageal thoracic cavity fistula with covered esophageal stent through nasal esophagus drainage tube is feasible and safe with clinical efficiency.

Objective To observe the spatiotemporal characteristics of the micro-structural injury in a rat model of diffuse axonal injury (DAI) and quantitatively assess the axonal injury severity in the vulnerable areas. Methods The 7.0 T MRI was performed in rats in DAI group (n =20) and control group ( n = 15 ) to synthesize the diffusion tensor imaging ( DTI) parameter map and calculate the parameter value of the vulnerable areas. Immunohistochemistry was used to detect β-APP expression in the vulnerable areas and the IPP software to quantitatively assess the axonal injury severity. Results Compared with the control group, FA and AD maps showed local signal defection or reduction in the corpus callosum and their values decreased significantly in the brain stem and corpus callosum in the DAI group (P ＜0.01 ). The integrated optical density (IOD) value of the vulnerable areas in the DAI group was significantly higher than that of the control group ( P ＜ 0. 01 ) , with the highest level in the brain stem (P＜0.05). The normalized FA, AD and ADC in the vulnerable areas were correlated negatively with the IOD (P ＜ 0.05). Conclusion DTI can detect invisible micro-structural injury in the vulnerable areas and quantitatively assess the axonal injury severity in vivo in the early stage.

Objective To evaluate the value of reducing radiation dose with ECG-pulsing and image quality in 64-row multi-alice CT coronary angiography.Methods Fifty-nine consecutive patients whose heart rates were less than 80 beat per minute and cardiac rhythm was regular were randomly divided into two groups from October 26, 2007 to March 12, 2008.Conventional technique of CT coronary angiography was employed in group 1, while ECG-pulsing technique was applied in group 2.CT dose index volume (CTDIvol) and dose length product (DLP) were obtained automatically, and then the corresponding effective dose (ED) were calculated.The quality scores were performed on obtained imaging by using double blind method.Student t-test was applied in the comparison of value of CTDIvol, value of ED and quality of imagiugbetween two groups.Results The value of CTDIvol was (70.0±1.1) and (39.0±2.7) mGy, the value of ED was (16.8±2.0) and (9.5±1.7) rosy in group 1 and group 2, respectively, which reached statistically significant differences between the groups(t=57.675,15.346 ,P <0.01, respectively). The quality scores of coronary images were 3.8±0.2 and 3.8±0.1 in the groups, which did not reach the statistical significance (t=-0.222, P 0.05).Conclusions The proper application of ECG-Pulsing technology in 64-slice spiral CT coronary angiography can reduce radiation dose significantly while having no influence on the quality of the imaging.

Objective To explore changes of metabolites in APP/ PS1 double transgenie mice of Alzbeimer disease (AD) by 1H-MR spectroscopy (1H-MRS) and the application value of in early diagnosis of AD.Methods 1H-MRS was performed in 35 APP/PS1 transgenie mice of AD ( study group) and 20 wild type mice ( control group) at age of 3, 6 and 9 months using a 7.0 T MR system.Sub-peak areas of N-acetyl aspartate (NAA), myo-inositol (mI) and creatine (Cr) in the cerebral cortex and hippocampus were measured, and the NAA/Cr and mI/Cr ratios were calculated.The changes in pathology between the two groups were compared.Using the lower limit of 95% confidence interval (CI) of the ml/Cr ratio and the upper limit of 95% CI of the NAA/Cr ratio of AD mice as the threshold, their influences on sensitivity,specificity and accuracy of various age groups of AD animals were compared.Comparison of the 1H-MRS indexes between study mice and wild type mice at each time point were conducted by a two-sample t test.Results The mean mI/Cr ratios of AD mice were 0.68± 0.03, 0.72± 0.04, and 0.77 ± 0.04 respectively at 3, 6 and 9 months of age; while they were 0.63 ± 0.04, 0.64 ± 0.03, and 0.64 ± 0.04 respoetively in control group, the difference was significant ( t = 2.814, 5.146, 14.437, P < 0.01 ).Compared with the control group, the mI/Cr ratio of the 3-month-old AD mice of the study group was significantly increased,and histological examination showed proliferation and activation of neuroglial cells in the cerebral cortex and hippoeampus.The mean NAA/Cr ratio were 1.17 ±0.08, 1.04 ±0.05, and 0.90 ±0.05 respectively at 3,6 and 9 months of age in study group, while they were 1.18 ±0.07, 1.16 ±0.07, and 1.18 ±0.08respectively in control group.There were no significant difference ( t = 0.752, P > 0.05 ) between the study group and control group at 3 months of age, and the NAA/Cr ratio decreased significantly only at 6 and 9 months of age ( t = - 8.514, - 5.646, P < 0.01 ).The immunohistochemical exam demonstrated the appearance of Aβ plaque.According to threshold of mI/Cr, the sensitivity of AD mice of 3, 6 and 9 months of age was 80% (28/35), 84% ( 26/31 ) and 85% ( 23/27 ), and the specificity was 85% ( 17/20 ),94% (17/18) and 100% ( 16/16), and the accuracy was 82% (45/55), 88% (43/49) and 91% (39/43),respectively.For NAA/Cr, the sensitivity of AD mice of 6 and 9 months of age was 84% (26/31) and 89% (24/27), and the specificity was 89% (16/18) and 100% (16/16), and the accuracy was 86% (42/49) and 93% (40/43), respectively.Conclusions NAA and mI are the most sensitive and specific markers for early assessment of AD, and change of mI is earlier than that of NAA.Quantitative analysis of mI may provide important clues for early diagnosis of AD.

Objective To label neural stem cells (NSCs) with superparamagnetic iron oxides (SPIO) and to explore the tropism of NSCs after transplantation into the hippocampus of APP/PS1 AD mice by MRI.Methods NSCs from C57BL/6 mouse were cultured and identified.Feridex and Poly-L-Lysine were added into the medium to be co-cultured to make magnetic labeled NSCs and transmission electron microscopy was used to identify the iron particles in NSCs.Transgenic (tg) and wild-type (wt) mice at 12 months of age were divided into three groups: SPIOs labeled NSCs group (A and C),unlabeled NSCs group(B).Feridex-labeled NSCs were migrated into the hippocampus of APP/PS1 AD mice to monitor in vivo by MRI.After 1,2,4 and 6 weeks,the mice were sacrificed and their brain tissues were sectioned to investigate the migration of SPIO labeled NSCs and compared with MRI.Results NSCs of C57BL/6 mice were cultured successfully.Transmission electron microscope showed visible iron granules in cytoplasm.MRI detection of labeled cells: T2WI and T2* WI showed remarkable low signal intensity at the hippocampus injection points 1 week after transplantation,particularly on T2* WI.Area of low signal intensity enlarged increasingly along the injection points after 2 weeks.At 4 weeks,area of low signal intensity spread throughout the hippocampus,but intensity shadowed Six weeks later,low signal intensity almost disappeared.There was no obvious low signal change in unlabeled cell transplantation group.For wt mice,size and location of low signal did not appear obvious change at all designated time points.Prussian blue positive cells were observed in the hippocampus,indicating that NSCs labeled with SPIO could survive,migrate and differentiate in the brain of the APP/PS1 AD mice.Changes of pathology were well correlated with the area where a signal intensity loss was observed in MRI 1,2,4 and 6 weeks after transplantation Conclusions Diffuse migration of transplanted NSCs labeled with SPIO is observed in the hippocampus in APP/PS1 tg mice,and MRI technique is an ideal method for tracking labeled stem cells after grafting in vivo.

Objective To explore the value of 1H-MRS on the evaluation of Alzheimer's disease (AD) with neural stem cells (NSCs) transplantation in an APP-PS1 double transgenic (tg) AD mouse model.Methods NSCs from C57BL/6 mice were cultured and amplified.APP-PS1 tg mice (n =30) aged 12 months were used as the study group,and mild-type mice (n =15) were used as the control group.Animals in the study group were randomized into two subgroups,the AD mice in one subgroup received NSCs transplantation (NSCs group) and in another subgroup received phosphate buffer saline (PBS,PBS group)in bilateral hippocampal CA1.Animals in the control group were not treated.Using a 7.0 T high-fieldstrength MR imager,1H-MRS was performed before and 6 weeks after transplantation to measure the area under the peak of n-acetyl aspartate (NAA),glutamate (Glu),myo-inositol ( mI),choline (Cho) and creatine (Cr) in the hippocampal area,NAA/Cr,Glu/Cr,mI/Cr and Cho/Cr ratio were calculated and compared with histopathological results (including Nissl's staining and electron microscope examination).Comparisons among NSCs,PBS and control groups were conducted by one-way ANOVA.Results NSCs from C57BL/6 mice were cultured successfully. Before transplantation,the mean NAA/Cr,Glu/Cr and mI/Cr in NSCs,PBS and control groups were 0.89 ± 0.05,0.88 ± 0.04 and 1.15 ± 0.05,0.40 ± 0.03,0.39 ± 0.03 and 0.45 ± 0.05,0.67 ± 0.05,0.67 ± 0.05 and 0.52 ± 0.04,respectively,and differences were statistically significant (F =148.918,7.529,59.468,P ＜ 0.01 ). There were no significant differences in NAA/Cr,mI/Cr and Glu/Cr ratios between NSCs and PBS groups before transplantation (t =0.147,0.096,0.207,P ＞ 0.05 ),but the differences were significant compared with the control group (t =0.255,0.467,0.171 and t =0.269,0.527,0.151,P ＜0.05).Six weeks after transplantation,the mean NAA/Cr,Glu/Cr and mI/Cr in three groups were 1.13 ±0.07,0.86 ±0.05 and 1.14 ±0.05,0.45 ± 0.04,0.38 ± 0.02 and 0.44 ± 0.03,0.58 ± 0.04,0.67 ± 0.04 and 0.53 ± 0.04,respectively,and differences were statistically significant ( F =112.092,23.076,44.367,P ＜ 0.01 ).NAA/Cr and Glu/Cr ratios were increased and mI/Cr was decreased in NSCs group,and the difference was significant compared with PBS group at the same time point ( t =0.271,0.071,0.089,P ＜ 0.05 ).There were no significant differences in NAA/Cr and Glu/Cr ( t =0.013,0.012,P ＞ 0.05 ),but there was a significant difference in mI/Cr between NSCs and control groups ( t =0.046,P ＜ 0.05).There were no significant differences in Cho before and after transplantation among the three groups (P ＞ 0.05 ). Nissl's staining showed that the number of neurons in the hippocampal area increased more significantly in tg mice receiving NSCs than that without receiving NSCs.Electron microscopy showed that most hippocampal NSCs in NSCs group were morphologically normal with abundant organelles,while hippocampal NSCs in PBS group were swollen with sparse synapses.Conclusion 1H-MRS is able to display intracranial metabolite changes before and after NSCs in APP-PS1 double transgenic AD mice and has an applicable value in evaluating the therapeutic effect of NSCs on AD.

Objective To evaluate the 1.5 T magnetic resonance imaging system to depict and track in vivo of magnetically labeled endothelial progenitor cells(EPCs),and to study the possibility for preventing the atherosclerotic plaque formation in New Zealand rabbit model of carotid arterial injury after transplantation.Methods New Zealand rabbit EPCs were isolated,confirmed,expanded and then incubated with home synthesized Fe_2O_3-PLL,Prussian blue stain was performed for showing intracellular irons.The model of carotid arterial injury was performed by 2.5F balloons,the group A of 8 rabbits received magnetically labeled EPCs,group B of 3 rabbits received fluorescent-labeled EPCs and the group C of 5 rabbits were given same volume saline injection after endothelial injury of the carotid artery.MR imaging and histology were performed and compared 4 days later for randomly chosen three rabbit,each from one of the three group;all the other rabbits were fed with high lipid diet and examed using MR imaging and histology after 15 weeks.Results Epcs labeling efficiency was more than 95% by Prussian blue stain, 4 days after transplantation of EPCs,only in group A,the injured endothelium of carotid artery had signal intensity loss in T_2 * WI,which were correlated well with the area where the most Prussian blue staining positive cells were found in histopathology analyses.The rabbits of group A and B which received EPCs transplantation exhibited fewer plaques formation than those of the group C(P