Objective To investigate the feasibility of low-c oncentration iso_osmolar contrast agent together with low tube voltage and iterative reconstruction algorithm in rabbit liver computed tonography (CT) perfusion imaging.Methods A total of 15 bealthy New Zealand rabbits were scanned twice of liver CT perfusion scans each with 24 hours interval.The first scan (routine group) was acquired at 100 kV and 100 mAs with ultravist (370 mg/ml),while the second (double low group) was acquired at 80 kV and 100 mAs with iodixanol (270 mg/ml) at 24 hours after the first scan.The obtained images were reconstructed with filtered back projection (FBP) and adaptive iterative dose reduction (AIDR-3D)algorithms in the controlled and experimental groups,respectively.The perfusion parameters including hepatic artery perfusion(HAP),portal vein perfasion(PVP),hepatic perfusion index(HPI),and total liver perfusion(TLP) and image quality as image quality score,average CT value of abdomen aorta,signalto-noise ratio(SNR),carrier-to-noise ratio(CNR),and figure of merit(FOM) were compared used pair ttest or Mann-Whitney U-test between the two groups wherever appropriate.The effective radiation dose and iodine intake were also recorded and compared.Results The image quality and perfusion parameters had no significantly different between the two groups except for FOM.The effective radiation dose and iodine intake were 38.79％ and 27.03％ lower in the double low group.Conclusions Low concentration iso _osmolar contrast agent (iodixanol,270 mg/ml) together with low tube voltage (80 kV) helps to reduce radiation dose and iodine intake without compromising perfusion parameters and image quality in liver CT perfusion imaging.

AIM:To study the telomere maintenance mechanism in mesenchymal stem calls(MSCs).METHODS:MSCs were isolated from healthy human bone marrow by their adherence to plastic and then were checked with CD14-FITC,CD45-FITC,CD44-FITC,HLA-DR-FITC,CD34-PE,CD29-PE and CD166-PE.Telomere length and ECTR DNA in MSCs were detected by Southern blotting.The localization of TRF1 and promyelocytic leukemia(PML)in MSCs were detected with immunofluorescence staining.TRAP protocol was performed to detect the telomerase activity in MSCs and MSCs-derived adipocytes.Western blotting and TRAP protocol were applied to measure telomerase activity of MSCs,which were synchronized by serum starvation and aphidicolin treatment.RESULTS:The telomere in length seemed shorter and relatively more homogeneous in MSCs and HeLa cells than that in WI-38-2RA cells.TRF1 did not concide with PML nuclear body in MSCs and HeLa cells while it exclusively did in WI-38-2RA cells.ECTR DNA was negative in MSCs and HeLa cells but positive in WI-38-2RA cells.Telomerase was negative in MSCs but it was positive in MSCs-derived adipocytes detected by TRAP.Moreover,a cell cycle-dependent expression profile of telomerase was found in MSCs when they were synchronized by serum starvation and aphidicolin treatment.Untreated MSCs expressed very low level of telomerase probed by Western blotting with 2C4 mAb,but the telomerase level had significantly increased when these cells were trapped in S phase.CONCLUSION:The telomere of MSCs is maintained by telomerase pathway instead of alternative lengthing of telomere(ALT)and the level of telomerase expression is associated with cell cycle stage.[

Objective To explore the related factors of anemia during pregnancy and provide scientific evidence for the primary prevention of anemia during pregnancy.Methods The pregnant women (≤ 12 pregnant weeks) who received the first pregnancy care in a local medical institution in Hunan province from June 2013 to November 2014 were included in this cohort study,and for them anemia had been excluded by physical examination.Baseline survey and follow up till childbirth were conducted for them.A queue-based nested case-control study (1 ∶ 2) was conducted (380 pregnant women with anemia detected in this study as case group,760 pregnant women without anemia randomly selected and matched by age,habitual residence during pregnancy as control group.And t test,x2 test and logistic regression analysis were conducted to identify related factors of anemia during pregnancy.Results Multivariate logistic regression analysis indicated that low family annual income level (net income) (OR=2.08,95％CI:1.22-3.59),low educational level (OR=2.09,95％CI:1.22-3.59),pre-pregnancy perm/hair dye (OR=2.23,95％ CI:1.63-3.05),early pregnancy vomiting (OR=2.51,95％ CI:1.56-4.03) were the risk factors for anemia during pregnancy.Intake of vitamin and trace element supplements (OR=0.69,95％ CI:0.50-0.94),frequent meat,fish,shrimp,egg intakes (OR=0.68,95％CI:0.49-0.92),frequent soy milk,milk intakes (OR=0.51,95％CI:0.27-0.95) were the protective factors for anemia during pregnancy.Conclusion A number of factors,such as family annual income level,education level,poisonous and harmful material contact,pregnancy reaction,nutrition,are related to the incidence of anemia during pregnancy,it is necessary to take preventive measures to reduce the incidence of anemia during pregnancy.