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Objective To synthesize a novel vector of chitosan-particles loaded with gadolinium (Gd-CPs) and observe the adhesion and absorption of the particles in the colon wall of mice with MR imaging in-vivo.Methods Chitosan particles (CPs) with and without gadolinium loaded were synthesized with the emulsion-droplet coalescence method.Sixteen mice were randomly classified into two groups.The suspension with Gd-CPs or with CPs was infused into the rectum of the 8 mice of each group,respectively.MR scans were performed before,during and 40 minutes after infusion for each mouse.Samples of the colon correlated to the enhanced area were obtained for electron microscopy examination.Signal intensity (SI) of ROIs in the wall of rectum or colon,muscles of the pelvis near the rectum and background were measured and corresponding relative SIs were calculated.Relative SI values between the two groups and pre- and post- infusion were compared with pared t test.Results Dimension of the Gd-CPs was about 500 nm,and content rate was about 30%. Values of relative SI of the rectum for pre- and post- infusion in the Gd-CPs group were 0.84±0.06 and 0.98±0.09(t=4.327,P＜0.01),respectively,while those in CPs group were 0.83±0.04 and 0.84±0.05(t=0.658.P＞0.05). The medial value of signal increase rate for CPs group was 19.0%.Gd-CPs particles were found inside the mucosal cells under the electron microscopy.Conclusion MR imaging in-vivo can reveal the phenomenon of adhesion and absorption of mucosa targeted chitosan particle carriers. Clinical MR imaging based on small animal coil is a good method to monitor colon mucosa targeted particle vectors in-vivo.

In the present study,healthy adults who had been residing at the average altitudes of 6,2260,and 2800 m for 10 years were recruited,and the number of red blood cells,the levels of hemoglobin,and HbA1C were tested.The results showed that the level of HbA1C in altitude 2800 m group was higher compared with the other 2 groups(5.80％ ± 0.50％ vs 5.39％ ± 0.47％,P＜0.05 ).Therefore,this difference should be considered when diagnosis and treatment for diabetes mellitus were made in the region.

Sixty-one newly-diagnosed diabetic patients from high altitude area were treated individually plus metformin 1.5 g/d for 14 days. The difference of oxygen partial pressure was 3.5 mm Hg (1 mm Hg=0. 133kPa) between altitude 2 260 m and 2 780 m districts. In these patients, their serum lactic acid was increased before treatment. At altitude 2 780 m district, serum lactic acid in middle-aged and elder groups were even higher [(3.90±0.85 vs 3.65±0.70), (4. 67±0.80 vs 3.69±0.78) mmol/L, both P＜0. 05＝. After 14-day treatment, serum lactic acid in middle-aged diabetic patients remained statistically unchanged [(4.50±0.50 and 3.79±0.62 ) mmol/L, P＞0.05], while that in elder patients was increased significantly [(5.59±0.55 and 5.27±0.43 ) mmol/L,P＜0. 05]. The results suggested that metformin should not be used or be used carefully in elder diabetic patients at high altitude area.

Objective　We established a model by using microfluidic chip that is a horizontal side by side diffusion system through microporous separating three adjacent channels in a triple-culture using neurons,astrocytes,and bEnd.3.Methods　(1)In the in vitro microphysiological system of neurovascular unit,we identified the seed density,seed time,seed sequence and seed method.(2)We adopt the repeated measures data of ANOVA to see whether there is significant difference in the viability when the three cell types are tri-cultured and separately mono-cultured.Results　(1) In the novel in vitro NVU model,the seed density of the neurons,astrocytes and bEnd.3 is 5×10^6~10×10^6 /ml,3×10^5~8×10^5个/ml and 1×10^5~5×10^5/ml.The seed sequence is from neurons to astrocytes to bEnd.3.The seed time is that after the previous seeded cells enter the exponential phase,the next cells will be seeded.(2)We adopt the repeated measures data of ANOVA to see whether there is significant difference in the viability when the three cell types are tri-cultured and separately mono-cultured.Conclusion　In this study,neurons,astrocytes and bEnd.3 were tri-cultured by using microfluidic chip.In this tri-culture model,these three kinds of cells have high cell viability.