1.Clinical outcomes of 241 cases with fetal ventriculomegaly
Nan CHU ; Bin ZHANG ; Yueping ZHANG ; Yingliu YAN ; Yunyun REN
Chinese Journal of Perinatal Medicine 2016;19(8):575-580
Objective To evaluate the pregnancy outcomes and prognosis of fetuses with different levels of ventriculomegaly.Methods Fetuses with ventriculomegaly subjected to the multidisciplinary consultation in the Obstetrics and Gynecology Hospital of Fudan University between January 2004 and December 2013 were included in this study.The fetuses were divided into three groups according to the width of the lateral ventricles on ultrasound examination as follows:mild ventriculomegaly (Mild Group,≥ 10 -<12 mm,151 cases),moderate ventriculomegaly (Moderate Group,≥ 12-<15 mm,56 cases) and severe ventriculomegaly (Severe Group,≥ 15 mm,34 cases).All cases were followed up with additional ultrasound scans during pregnancy and follow up was continued until the children were almost nine years old.Chi square test,Fisher's exact test and Bonferroni method were used to analyze the data.Results Two hundred and forty one fetuses were followed up.Ninety-one cases were terminated,and 150 were born (105 cases in Mild Group,30 cases in Moderate Group,and 15 cases in Severe Group).During ultrasound follow up of the 150 cases,the lateral ventricle width regressed in 42 cases (28.0%) and remained stable in 108 cases (72.0%).In the regressed group,the ventricle width in 31 cases in the Mild Group regressed to normal and a hearing abnormality was noted in one case after birth.In the Moderate Group,the lateral ventricle width in nine cases regressed to normal,one case had mild ventriculomegaly,and none of these cases showed abnormalities after birth.One case in the Severe Group showed no abnormalities,while the width of the lateral ventricles decreased to 14.0 and 16.0 mm.With regard to the outcomes of lateral ventricle width with or without regression,one of 42 cases in the regressed group had a significant abnormality,while 19 of 108 cases in the stable group [eleven cases (14.9%,11/74) in Mild Group,two (10.9%,2/20) in Moderate Group,and six (6/14) in Severe Group] showed significant abnormalities.Statistically significant differences were found between the two groups [2.4%(1/42) vs 17.6%(19/108),x2=4.940,P=0.026].When the outcomes of the three groups were compared,12 of 105 cases in the Mild Group (11.4%),two of 30 cases in the Moderate Group (6.7%),and 6 of 15 cases in the Severe Group (6/15) had significant abnormalities.Statistically significant differences were found between the three groups (x2=6.908,P=0.032).Statistical significance was observed in the Moderate Group and Severe Group (x2=4.929,P=0.026),while the Mild Group had a more favorable prognosis than the Severe Group (x2=5.266,P=0.022).Chromosomal examinations were carried out in 57 cases and the incidence of chromosomal abnormalities was 8.8%(5/57) [7.0% (3/43),1/8 and 1/6 in the three groups,respectively].Infection screening was performed in 29 cases and one case was found to be positive for rubella virus-IgM,two cases were positive for cytomegalovirus-IgM,and one case was positive for toxoplasma gondii-IgM.Conclusions Pregnancy outcomes and the prognosis of fetal ventriculomegaly are associated with the degree and progression of ventricular dilatation.
2.Immune function changes of non-small cell lung cancer patients after chemotherapy
Huiru ZHENG ; Meiling JIN ; Tao REN ; Lei ZHANG ; Yiwei CHU
Fudan University Journal of Medical Sciences 2009;36(6):696-700
Objective To compare the proportion of CD3~+T cell and CD4~+CD25~(high) regulatory T cell (Treg cell) and the production of inferon γ ( IFN-γ) and interleukin-12 (IL-12) in peripheral blood mononuclear cells (PBMC) between patients with non-small cell lung cancer (NSCLC) and healthy people, and to analyze the changes of CD3~+T cell, CD4~+CD25~(high)Treg cell, IFN-γ and IL-12 of NSCLC patients before and after chemotherapy, so as to determine immune function changes of NSCLC patients caused by chemotherapy. Methods Twenty NSCLC patients and 20 healthy volunteers according to the including criteria were selected. Three mL of blood was drawn from NSCLC patients before chemotherapy (0 d), on the 3~(rd) day (3 d) and 7~(th) day (7 d) after chemotherapy. PBMC cells were separated from the blood samples. The proportions of CD4~+CD25~(high)Treg cell and CD3~+T cell (%) in PBMC were tested by FACS, and the IFN-γ and IL-12 (pg/mL) in the supernatants were also detected. Results The proportions of CD3~+T cell in NSCLC patients on 0, 3 and 7 d were (55.15±20.11)%,(57.73±14.08)% and (62.79±7.80)%,respectively, and there was no statistical difference between any two of these results. The proportion of CD4~+CD25~(high)Treg cell in healthy volunteers was (2.14±0.85)%, while that of NSCLC patients was (2.76±0.53)% on 0 d with statistical difference compared to the healthy volunteers (P<0.05). The CD4~+CD25~(high)Treg cell proportion (%) of NSCLC patients on 3 d and 7 d were (2.54±0.57)% and (2.72±0.29)%, respectively, which were both significantly lower than that of 0 d. On 3 d it was even much lower than that on 7 d (P<0.05). IFN-γ and IL-12 of NSCLC patients on 0 d were (34.36±4.38) pg/mL and (33.24±4.36) pg/mL, and no statistical difference was observed when compared with (34.36±4.38) pg/mL and (33.24±4.36) pg/mL in the healthy volunteers. On 3 d and 7 d, IFN-γ of NSCLC patients were (40.42±5.66) pg/mL and (39.27±6.07) pg/mL, respectively, and both were higher than that on 0 d (P<0.05); IL-12 of NSCLC patients were (35.51±5.03) pg/mL and (38.62±6.44) pg/mL, also both were higher than that on 0 d (P<0.05). Conclusions This study suggests that chemotherapy can improve immune functions of NSCLC patients, and may reinforce the anti-tumor immune response.
3.Investigation of the Antiplatelet Function of Clopidogrel by Thrombelastography and Light Transmission Aggregometry
Junwei REN ; Yanping ZHANG ; Yulong CONG ; Duwu CHU
Journal of Modern Laboratory Medicine 2014;(6):48-50,51
Objective To detect the antiplatelet function of clopidogel by Thrombelastography (TEG)and light transmmi-tance aggregometry (LTA)and analyze efficiency of two methods.Methods ①Venous blood samples were taken from 48 outparients and inpatient with acute corotary syndrome (ACS)in PLA General Hospital,including unstable anqina,ST seg-ment elevation myocardial infarction and non ST segment elevation myocardial infarction (32 males,16 females)by random number table from March to July 2011,whose average age was 73 (62~90).②All of them were served 160 mg aspirin and 300 mg clopidogrel after they were in hospital at first time,and then served with 75 mg/d clopidogrel for 9 months.After that,venous blood samples were drew from them who were served clopidogrel 2 hours later.③Platelet aggregation function was assayed with LTA and TEG.All volunteers were signed informed consent and the experiment was approved by the hos-pital ethics committee.Results The platelet aggregation rate detected with LTA induced by adenosine diphosphate (ADPL-TA-INDU)was 40~80% in 41 individuals (85.4%),>80% in 7 individuals (14.6%),coefficient of variation (CV)was 0.19.The inhibition ration of platelet function (INHI)detected with TEG (ADPTEG-INHI)was 10~60% in 40 individu-als (83.3%),<10% in 2 individuals (4.2%),>60 in 6 individuals (12.5%),CV was 0.54.The sum of ADPLTA-INDU and ADPTEG-INHI (ADPLTA-INDU+ADPTEG-INHI)tended to a constant (Mean=98%,SD=12.1).There was no significant indifference between every (ADPLTA-INDU+ADPTEG-INHI)and their Mean (98%)by paired t-test.The ADPLTA-INDU was negative correlated with ADPTEG-INHI (r=-0.75,P<0.01).Conclusion The effect of clopidogrel was mild and the efficiency of TEG and LTA was similar in detecting the antiplatelet function of clopidogrel,but the preci-sion of TEG was lower than LTA.
4.Activity of plasma lecithin cholesterol acyltransferase and its lipid metabolism in patients with ischemic cerebrovascular disease
Kaiqiu CHU ; Xiaoyan TANG ; Qingwu TIAN ; Lisheng REN ; Shaoyan ZHANG
Chinese Journal of Tissue Engineering Research 2005;9(17):243-245
BACKGROUND: Abnormal lipid metabolism is one of the risk factors in patients with ischemic cerebral disorders, and is correlated with the changes of lecithin cholesterol acyltransferase activity.OBJECTIVE: To observe the relationship between the changes of lecithin cholesterol acyltransferase activity and lipid content in red blood cell membrane.DESIGN: A case-control study(experimental group with control as standard level).SETTING: Department of clinical laboratory, emergency room and department of neurology of a hospital affiliated to a medical college of a university.PARTICIPANTS: Totally 105 inpatients and outpatients with cerebrovascular diseases were selected from the Department of Neurology, Affiliated Hospital of Medical College of Qingdao University, from March 2002 to December 2003. They accorded with the Diagnostic Criteria set at the Second National Conference on Cerebrovascular Diseases. A total of 42 patients with cerebral arteriosclerosis and 63 patients with cerebral infarction were selected as patients group consisting of 67 males and 38 females. Another 65 healthy people receiving physical examination in the hospital, 36 males and 29 females, were selected as control group.METHODS: Venous blood of 8 mL was drawn from the participants on an empty stomach. We assayed the activity of lecithin cholesterol acyltransferase,high density lipoprotein cholesterol, low density lipoprotein cholesterol,apolipoprotein A1 and apolipoprotein B. Red blood cell membrane cholesterol was determined by phthalyl aldehyde-acetometry and red blood cell membrane phospholipid was determined by chemical quantitative analysis.MAIN OUTCOME MEASURES: Changes of lecithin cholesterol acyltransferase activity and lipid content in red blood cell membrane in patients group and control group.RESULTS: According to intention analysis, all the 105 patients in patients group and 65 patients in control group entered the results analysis. Activity of lecithin cholesterol acyltransferase: Activity changes in cerebral arteriosclerosis group and cerebral infarction group were obvious lower than those in control group[(2.14±0.72) kat/L, (2.06±0.80) kat/L, and(2.61± 0. 74) kat/L, P < 0.01 ] . Level of high density lipoprotein cholesterol and apolipoprotein A1: The level in cerebral arteriosclerosis group and cerebral infarction group was obvious lower than that in control group[ (1.32±0.33) mmol/L, (1.37±0.33) g/L, (1.28±0.33) mmol/L; (1.27±0.31) g/L, (1.60±0.43) mmol/L, (1.60±0.43) g/L, t=2.72 to 5.01, P < 0.01 ]. Content of low density lipoprotein cholesterol and red blood cell membrane-cholesterol: The content in cerebral arteriosclerosis group and cerebral infarction group was obvious higher than that in control group [ (2.94 ± 0. 82) mmol/L, (0.63 ±0.05) mmol/g, (3.02 ±0.79) mmol/L;(0.60 ±0.07) mmol/g, (2.56 ±0. 58) mmol/L, (0.57 ±0.05) mmol/g, P < 0. 01 ] . Moreover, the activity of lecithin cholesterol acyltransferase was positively correlated with high density lipoprotein cholesterol and apolipoprotein A1(r=0.247, P <0.05; r=0.303, P <0.01), but was negatively correlated with low density lipoprotein cholesterol and red blood cell membrane cholesterol(r= -0.212, P <0.05;r= -0.346, P <0.01).CONCLUSION: In patients with ischemic cerebral disorders, the major change of plasma lipid is the decrease of lecithin cholesterol acyltransferase,but it is not secondary to cerebral infarction. The activity of lecithin cholesterol acyltransferase is positively correlated with high density lipoprotein cholesterol and apolipoprotein A1, but is negatively correlated with low density lipoprotein cholesterol and red blood cell membrane cholesterol.
5.Management of severe rotational throracolumar fracture and dislocation with posterior decompression by vertebral body resection, interbody bone fusion and transpedicular screw internal fix-ation
Zhengfeng ZHANG ; Yue ZHOU ; Jian WANG ; Changqing LI ; Tongwei CHU ; Xianjun REN ; Weidong WANG ; Nianchun ZHANG
Chinese Journal of Trauma 2010;26(1):32-35
Objective To explore feasibility and therapeutic effect of posterior decompression by vertebral body resection, interbody bone fusion and transpedicular screw internal fixation in treatment of severe rotational throracolumar fracture and dislocation. Methods From October 2007 to July 2008, nine patients with severe rotational throracolumar fracture and dislocation classified as AO C types under-went decompression by vertebral boby resection, intervertebral bone fusion and transpedicular screw inter-nal fixation via a posterior midline small incision. There were eight males and one female, at age range from 23 to 54 years. All patients involved levels at T_(11)-L_2. According to AO classification, there were three patients with type C1 bursting fractures with rotational dislocation, five with distraction fracture com-bined with rotational dislocation and one with rotational distraction shear fracture/dislocation. The preop-erative Frankel Grading was Grade A in three patients, Grade B in one, Grade C in four and Grade D in one. Postoperative neurological status, the correction and loss of dislocation and the location and union of bone graft were reviewed. Results All patients received successful operation, with operation time of 3.5-5.8 hours (mean 4.4 hours), blood loss of 1 200-3 500 ml (mean 1 800 ml). The follow- up period in nine patients was 3-12 months (mean seven months). Postoperative X-ray photographs showed that the dislocation in all patients was reduced, the spine curvature was recovered to normal and the intervertebral bone graft was well fixed. Three patients at Frankel Grade A had no improvement, one at Grade B was improved to Grade C. Of four patients at Grade C, three patients were improved to Grade D. The follow-up showed bony fusion in all patients, with no loosening, dislocation or breakage of the internal fixation or implants. Conclusions For severe rotational throracolumar fracture and dislocation, decompression, reduction, fusion and fixation are rather difficult, while sufficient posterior decompression by vertebral body resection, rigid interbody bone fusion and transpadicular screw internal fixation can be an effective alternative measure.
6.A clinical study of ulinastatin combining with continuous blood purification in the treatment of patients with multiple organ dysfunction syndrome
Hongsheng REN ; Jinjiao JIANG ; Chunting WANG ; Dongqing YU ; Jicheng ZHANG ; Mei MENG ; Yufeng CHU ; Changjun JIN
Chinese Journal of Emergency Medicine 2008;17(6):622-626
Objective To observe the clinical efficacy of ulinastatin(UT) conjoined to high flow continuous blood purification( CBP) in the critical patients with multiple organ dysfunction syndrome(MODS). To evaluate the therapeutic potential of UT and CBP in systemic inflammatory response syndrome (SIRS) , severe sepsis( SS) , acute lung injury (ALI) and acute respiratory distress syndrome (ARDS). Method A total of 122 cases of emergency and critical patients with a score of more than 15 counted up from APACHE H (acute physiology and chronic health evaluation 11 ) were randomly divided into Ulinastatin treatment group (UT group, n = 35) .continuous blood pu-rification(CBP group, n = 31),UT plus CBP (combine group, n = 30) and routine treatment group (control group, n =26). Routine treatment was given to patients of all groups, and patients of UT group had Ulinastatin 0.4 MIU given intravenously every 8 hours for 7 days in addition. Patients of CBP group were managed with continuous blood purification round the clock for 7 days and those of combine group were treated with UT plus CBP for 7 days.The efficacy of the treatment in four groups was assessed,and serum high sensivity reactive protein(hs-CRP) and IL-6 levels were measured on admission and comparison was made between values of biomarkers taken before and 1 d,3 d,and 7 d after treatment in four groups. The changes in WBCs,arterial gas analysis and the oxygena-tion index PaO2/FiO2 were checked, and at the same time, the APACHE II values and the incidence of MODS were compared within four groups. Results (1)One, three and seven days after treatment the plasma hs-CRP and IL-6 levels in UT and CBP groups were reduced significantly more than those in control group ( P < 0. 05), and in combine groups those were more dramatically lowered ( P < 0.05, P < 0.01). Before treatment there was no significance diffience in those values between groups, and there was on diffience in those values between 3 rd day and 7 th day after treatment ( P > 0.05). (2) The 1 st,3 rd and 7 th day after treatment the arterial gas PaO2/FiO2 index in UT and CBP groups was improved more than that in control group ( P < 0.05) , and it in combine group was most significant improved (P < 0.05,P < 0.01). The ALT and creatinine were lower than those in control group ( P < 0.05), and there were no significant differences in ALT and creatinine between groups before treatment (P > 0.05). (3) The 1 st,3 rd and 7th day afer treatment,the APACHE II values in UT and CBP groups were decreased more than those in control group ( P < 0. 05) , and therefore, the incidence of MODS was lower ( P < 0.05). Conclusions Ulinastatin could significantly inhibit the production of inflammatory cytokines and CBP could effectively eliminate inflammatory factors from blood, and the combination of these two approaches produce a more effective therapeutic potential for preventing MODS development.
7.Risk factors of gastrointestinal bleeding in patients supported with mechanical ventilation
Yufeng CHU ; Yi JIANG ; Mei MENG ; Jinjiao JIANG ; Jicheng ZHANG ; Hongsheng REN ; Chunting WANG
Chinese Journal of Emergency Medicine 2010;19(7):740-743
Objective To identify the incidence and risk factors of gastrointestinal bleeding in patients supported with mechanical ventilation over 48 hours. Method A total of 127 ICU patients supported with mechanical ventilation for over 48 hours were enrolled from January 1, 2007 to December 31, 2008 for the retrospective study. Exclusion criteria included the history of gastrointestinal bleeding and ulcer, recent gastrointestinal surgery, brain death and active bleeding from nose or throat. Demographics of patients including age, diagnosis at admission, duration of ICU stay, duration of mechanical ventilation, pattern and parameters of ventilation, ICU mortality, A-PACHE II score, multiple organ dysfunction score, and the results of biochemical assays including renal, hepatic and coagulation functions were recorded. Risk factors of gastrointestinal bleeding were analyzed by using univariate analysis And multiple logistic-regression analysis. Results Of the 127 patients, the incidence of gastrointestinal bleeding was 41.7% . and among them 3.9% patients suffered from clinically significant bleeding. However, the independent risk factors of gastrointestinal bleeding were the peak inspiratory pressure > 30 cmH20 (RR = 3.73, 95% CI = 1.59-9.46), renal failure (RR = 1.16,95% CI = 1.02 - 2.32), PLT count <50× 109 L-1(RR = 2.67, 95% CI = 1.32 - 15.78) and prolonged APTT (RR = 4.58, 95%CI = 2.32 - 12.96). The good entetal nutrition had a beneficial effect to the avoidance of gastrointestinal bleeding ( RR = 0.30, 95% CI = 0. 13 - 0.67). Conclusions The incidence of gastrointestinal bleeding is high in patients supported with mechanical ventilation, and the bleeding usually occurs within the first 48 hours. High pressure ventilator setting, renal failure, decreased PLT count and prolonged APTT are significant risk factors of gastrointestinal bleeding. However, the good enteral nutrition is the independent protective factors.
8.Effects of fluid resuscitation and hemofiltration on Alveolar-arterial oxygen pressure exchange
Hongsheng REN ; Chunting WANG ; Yufeng CHU ; Jinjiao JIANG ; Jicheng ZHANG ; Mei MENG ; Guoqiang QI ; Min DING
Chinese Journal of Emergency Medicine 2010;19(12):1300-1303
Objective To evaluate the effects of fluid resuscitation and large-volume hemofiltration (HVHF) on the Alveolar-arterial oxygen exchange in patients with refractory septic shock. Method A total of 89 intensive care patients with refractory septic shock treated with fluid resuscitation and/or HVHF were enrolled between August 2006 and December 2009. All the patients were randomly divided into two groups. In group A, patients were treated with fluid resuscitation, n = 41 cases) and in group B, patients were treated with large-volume hemofiltration and fluid resuscitation, n =48). The O2 content of central venous blood(CcvO2), arterial oxygen content (CaO2), Alveolar-arterial oxygen pressure difference (P(A-a)DO2), the ratio of arterial oxygen pressure/alveolar oxygen pressure (PaO2/PAO2), respiratory index (RI) and oxygenation index (OI) were checked. The levels of oxygen exchange in two groups were detected by arterial blood gas analysis before treatnent, 24 hour, 72 hour and 7 days after treatment. The APACHE Ⅱ scores in patients with refractory septic shock were measured before and the 7th day after treatment with HVHF and/or fluid resuscitation respectively. Data were analyzed by using t -test and chi-square test to compare the differences and ratio between two groups and were expressed in mean ± standard deviation, and the analysis of variance was done with SPSS version 12.0 software. Results ① The differences in CcvO2 and CaO2 between two groups were[(0.60±0.24) vs. (0.72±-0.28), P <0.05 and (0.84±0.43) vs. (0.94±0.46), P <0.05]; and the oxygen extraction rates (O2ER) were significantly different between two groups [(28.7±2.4) vs. (21.7±3.4), P<0.01];② The levels of P(A-a)DO2、ratio of PaO2/PAO2、RI and OI in group B were reduced more significantly than in group A (P<0.05 or P<0.01);③The APACHE Ⅱ scores in both groups were gradually reduced after treatment for 7 days, and the APACHE Ⅱscore in group B on the 7th day of treatment were lower than that in group A[(17.2 ± 6.8) vs. (8.2 ± 3.8), P < 0.01]. Conclusions Fluid resuscitation and HVHF could improve alveolar-arterial-oxygen exchange in patients with refractory septic shock, and at the same time decreased the APACHE Ⅱ scores, improving the survival rate of patients.
9.Antimicrobial Resistance and Staphylococcal Cassette Chromosome mec Genotype of Meticillin-resistant Staphylococcus aureus from Lower Respiratory Tract
Haiqing CHU ; Yibo ZHANG ; Lizhong HAN ; Shengxiang REN ; Lan ZHAO ; Jinming LIU ; Yuxing NI
Chinese Journal of Nosocomiology 2009;0(17):-
OBJECTIVE To investigate antimicrobial resistance and molecular epidemiology profiles of meticillin-resistant Staphylococcus aureus(MRSA)sampled from lower respiratory tract.METHODS Totally 107 MRSA strains were isolated from lower respiratory tract specimens at Shanghai Pulmonary Hospital between Dec 2005 and Dec 2006.PVL genes were detected by PCR.The genotypes of SCCmec were identified by multiplex PCR.The antimicrobial resistance of MRSA were tested by Kirby-Bauer agar dilution.We also performed the homology of 32 MRSA strains using pulsed-field gel electrophoresis(PFGE).RESULTS All of the 107 MRSA strains were negative in the PVL locus detection and the most frequent SCCmec types were type Ⅲ(81.3%),the others including type Ⅱ(15.9%),type Ⅳ(2.8%),type Ⅰ and type Ⅴ were not found in this group.Those 3 different types of SCCmec were all resistant to ?-lactam antibiotics,less resistant to rifampin,and susceptible to vancomycin,teicoplanin and daptomycin.The resistant rate of those 3 types were different to the non-?-lactam antimicrobial drugs such as trimethoprim/sulfamethoxazole,clindamycin,erythromycin,gentamicin,levofloxacin,and tetracycline,the resistant rate in the types Ⅱ and Ⅲ was significantly higher than the type Ⅳ.PFGE analyses assorted the 32 MRSA strains into 4 PFGE patterns:pulsotype A(25 strains),including subtypes A1(17strains),A2(1 strain)and A3(7 strains);pulsotype B(5 strains),pulsotype C(1 strain),and pulsotype D(1 strain).CONCLUSIONS This study does not found positive PVL locus in the MRSA strains in our hospital,the most frequent SCCmec types are type Ⅲ and some are type Ⅱ.PFGE presented that there are outbreaks of MRSA in ICU ward and TB ward No 5 at that time and the pandemic strains are subtypes A1 and A3,most of these MRSA strains are multiple resistant,which deserves attention from both the clinical staff and infection-control department of the hospital.
10.Genome-wide DNA methylation changes induced by low dose radiation in mouse
Jingzi WANG ; Youwei ZHANG ; Xiaobei MAO ; Xiaobei LIU ; Lili REN ; Xiaoyuan CHU
Chinese Journal of Radiological Medicine and Protection 2013;33(4):341-345
Objective To study the whole genome DNA methylation changes induced by low dose radiation (LDR) in mouse,and mRNA expression profiles of DNMT1 and MBD2 in peripheral blood mononuclear cell (PBMC) and tissues.Methods Thirty male BALB/c mice were randomly divided into 3 groups:control,single exposure (0.5 Gy),and fractionated exposure of 6 MV X-rays for 10 d (0.05 Gy/d × 10 d).Control mice were sham-treated.To determine the immediate (early) effect of irradiation,15 mice (5/group) were sacrificed 2 h after the last irradiation.The other 15 mice were sacrificed 1 month after the last irradiation (delayed effect).Before sacrifice,blood was sampled immediately.Kidney,liver,spleen,brain and lung tissues were collected.A global DNA methylation quantification Kit and highperformance liquid chromatography (HPLC) were used to investigate the methylation level in blood DNA.The expressions of DNMT1 and MBD2 were determined by RT-PCR.Results For the early effects of irradiation,as compared with controls,fractionated exposure to X-ray irradiation led to the significant depression of global DNA methylation level in blood (t =10.19 and 8.93,P < 0.05).DNMT1 and MBD2 mRNA were down-regulated in PBMC,kidney and liver (t =5.06,3.01,3.97,12.25,3.50 and 3.73,P <0.05),and MBD2 was also down-regulated in spleen (t =3.03,P < 0.05).However,no changes were observed in single exposed group.As for the delayed effects,the methylation levels of blood were not changed in the single or fractionated exposed groups,and only MBD2 mRNA was down-regulated in PBMC and brain of fractionated exposed group (t =3.52 and 2.85,P < 0.05).Conclusions Fractionated LDR exposure can induce genome DNA hypomethylation,which is tissue-specific,and may be related with down-regulation of DNMT1 and MBD2.