白斑脱落粘膜上皮细胞与组织上皮细胞微核率相关性分析

目的 检测口腔白班患者脱落粘膜细胞微核细胞率及相应组织细胞微核细胞率,并进行相关性分析,为将该项指标应用于口腔白斑的治疗和判断预后提供依据。方法 采用Ｆｅｕｇｌｅｎ染色方法,对５９例单纯增生、３２例轻和中度异常增生性白斑及２８例重度异常增生性白斑和口腔鳞癌患者的口腔脱落粘膜细胞和组织上皮细胞微核进行了检测,同时检测了１００例健康人的口腔脱落粘膜细胞微核作为正常对照。结果 口腔白斑患者脱落粘膜细胞微     

Investigations into the role of inflammation in normal tissue response to irradiation

Purpose

Radiation-induced inflammation and production of reactive oxygen species (ROS) play a critical role in normal tissue response. In this study we have examined some aspects of these effects in lung and skin.

Methods

The superoxide dismutase (SOD) catalase mimetic, EUK-207, and genistein, an isoflavone with anti-inflammatory properties, were given post-irradiation and micronuclei (MN) formation was determined in cells derived from irradiated lung and skin. Changes in breathing rate were measured using a plethysmograph following irradiation of C57Bl6 mice knocked out for tumor necrosis factor (TNF)-alpha or its receptors, TNFR1/2, or treated with endotoxin (lipopolysaccharide - LPS).

Results

Both EUK-207 and genistein given after irradiation caused a large reduction in MN levels observed in lung cells during 14 weeks post-irradiation but ceasing treatment resulted in a rebound in MN levels at 28 weeks post-irradiation. In contrast, treatment with EUK-207 was largely ineffective in reducing MN observed in skin cells post-irradiation. Knock-out of TNF-alpha resulted in a reduced increase in breathing rate (peak at 12 weeks post-irradiation) relative to wild-type and TNFR1/2 knock-out. Treatment with LPS 1 h post-irradiation also reduced the increase in breathing rate.

Conclusions

The increase in MN in lung cells after treatment with EUK-207 or genistein was stopped suggests that continuing ROS production contributes to DNA damage in lung cells over prolonged periods. That this effect was not seen in skin suggests this mechanism is less prominent in this tissue. The reduced level of radiation pneumonitis (as monitored by breathing rate changes) in animals knocked out for TNF-alpha suggests that this cytokine plays a significant role in inducing inflammation in lung following irradiation. The similar effect observed following LPS given post-irradiation suggests the possibility that such treatment modifies the long-term cyclic inflammatory response following irradiation in lungs.     

Genotoxic Effects and LC<Subscript>50</Subscript> Value of NaOCl on <Emphasis Type="Italic">Orthrias angorae</Emphasis> (Steindachner 1897)

Studies show that different organisms used as bio-indicators have indicated several genotoxic and mutagenic effects of disinfected waters. In this study, the 96 h LC(50 )mean value of NaOCl for Orthrias angorae was calculated to be 0.5509 mg/L. The results showed that NaOCl is highly toxic to O. angorae specimens. Statistical analysis demonstrated a significant increase in micronuclei after the induction of 0.5 mg/L NaOCl concentration after 36 h. The same increase has been reported for 0.37 and 0.5 mg/L NaOCl concentrations after 72 h. Even though the MN frequency of 0.37 mg/L was similar after 36 and 72 h, only 72 h micronuclei frequency was statistically significant. The 72 h MN frequency of the negative control group was smaller than 36 h MN frequency of the negative control group. This discrepancy has led to 72 h MN frequency being statistically significant. MN frequency of 0.25 mg/L NaOCl concentration was insignificant when compared to negative test groups. The benzene treatment also caused a significant increase (p < 0.01) in the frequency of micronucleated erythrocytes.     

应用基因重组细胞模型研究苯并[a]芘的细胞毒性和遗传损伤效应

目的 利用经基因重组构建的具有细胞色素P450 1A1(CYP1A1)代谢活性的人支气管上皮细胞(16HBE)为体外模型,研究苯并[a]芘[B(a)P]的细胞毒性和遗传效应改变.方法 应用实时定量PCR方法检测细胞的CYP1A1和微粒体环氧化物水解酶(mEH)的mRNA水平.细胞分0、1、5、10、20 μmol/L B(a)P处理组,应用胞质分裂阻滞微核细胞组学技术综合评价B(a)P的有害生物效应,其中核分裂指数、细胞凋亡率和细胞坏死率等指标评价B(a)P的细胞毒性,微核、核质桥和核芽的发生率检测B(a)P的遗传损伤效应.结果 CYP1A1和mEH在16HBE-CYP1A1细胞中有较高表达,mRNA相对含量分别是7.8×10~(-4)和0.030.B(a)P作用后,16HBE-CYP1A1细胞1、5、10、20μmol/L处理组核分裂指数分别为1.92±0.04,1.71±0.01,1.61±0.04,1.41±0.01,低于对照组(2.08±0.03);双核细胞率分别为(76.33±3.51)%、(66.33±0.58)%、(51.67±1.53)%、(39.00±1.00)%,低于对照组的(82.67±6.66)%;细胞坏死率分别为(1.93±0.42)%、(2.20±0.53)%、(8.07±0.90)%、(15.27±2.80)%,高于对照组的(0.47±0.11)%,差异均有统计学意义(F值分别为899.94、303.33、240.87,P值均<0.01).而凋亡细胞随着B(a)P作用剂量的增加出现先增高后降低的趋势,分别为(1.20±0.53)%、(2.00±0.20)%、(1.47±0.12)%、(1.20±0.00)%、(1.20±0.00)%.遗传损伤效应分析中发现,随B(a)P作用浓度的增加,核质桥发生率随之增加,分别为(4.67±2.89)‰、(7.33±1.53)‰、(10.67±2.08)‰、(11.00±1.00)‰;核芽发生率也随之增加,分别为(2.33±0.58)‰、(4.00±1.00)‰、(5.00±1.00)‰、(7.67±1.16)‰,均有剂量-效应关系(F值分别为50.23、121.09,P值均<0.01).在B(a)P低于10 μmol/L组中,微核率也随B(a)P作用浓度的增加而升高,分别为(8.33±3.21)‰、(14.67±1.15)‰,但在20 μmol/L组,微核率为(16.67±2.88)‰,低于10 μmol/L处理组[(17.67±2.08)‰].在空载质粒细胞16HBEV中,细胞毒性出现较晚,在5、10、20 μmol/L组中,微核、核质桥和核芽的发生率[分别为(6.37±2.08)‰、(9.33±1.52)‰、(9.33±3.21)‰;(4.33±1.53)‰、(6.00±2.65)‰、(5.33±1.53)‰;(2.33±0.58)‰、(3.33±1.16)‰、(3.67±1.16)‰]没有明显的组间改变.结论 B(a)P代谢活化后可导致遗传损伤效应增加,这可能与细胞的核分裂指数降低、细胞坏死率增加或细胞凋亡受抑制有关.     

头颈部放疗患者的口腔黏膜脱落细胞微核计数的初步研究

目的:探讨头颈部放疗患者的口腔黏膜脱落细胞微核数。方法:随访1978～2001年接受过头颈部放疗的患者30例、2002年接受放疗的头颈部肿瘤患者30例和健康志愿者30例,对口腔黏膜脱落细胞进行微核计数。结果:正常对照组、放疗前患者和放疗后患者三者间的脱落细胞微核数差异无统计学意义(P>0.05)。放疗结束时患者的脱落细胞微核数高于放疗前患者和放疗后患者的脱落细胞微核数,且有统计学意义(P<0.01)。结论:反映微核数的改变局限于肿瘤区和放射线对口腔黏膜上皮损伤的可逆转性,并提示脱落细胞微核数可用于放疗后患者肿瘤继发的监测。     

甲醛诱导小鼠骨髓细胞微核和DNA损伤的研究

目的 研究甲醛对小鼠的遗传损伤作用.方法选择昆明种小鼠30只,随机分为5组,用分析纯甲醛配制成0、1.25、2.50、5.00mg/m^3浓度,对小鼠进行静式吸入染毒,2 h/d,连续15 d,阳性对照组腹腔注射环磷酰胺40 mg/kg,每天1次,连续2 d.采用微核试验和彗星试验检测甲醛的遗传毒性.结果甲醛能引起小鼠骨髓细胞微核率升高和外周血淋巴细胞DNA不同程度的电泳迁移,与对照组比较,差异有统计学意义（P＜0.05）.微核率随着甲醛剂量的增加而升高;迁移率和迁移度在1.25 mg/m^3剂量组与2.50、5.00 mg/m^3组之间差异有统计学意义,2.50 mg/m^3与5.00 mg/m^3组之间差异无统计学意义.结论甲醛对小鼠有遗传损伤作用,随着甲醛剂量的增加,损伤加重.     

不同采样时间小鼠网织红细胞微核率变化的流式细胞术研究

目的：应用流式细胞术研究两次给药后不同采样时间小鼠外周血网织红细胞微核率的变化，探讨流式细胞术检测微核方法的应用性。方法：NIH小鼠两次腹腔注射环磷酰胺(cyclophosphamide，CP)40mg／kg BW(两次给药间隔24h)，于第二次给药后6、12、18、24、30、36、48h和72h采外周血-85℃甲醇固定、PI和CD71染色进行流式细胞术检测，每个样本分析10000个网织细胞，同时进行外周血涂片，Giemsa染色显微镜检测，每个样本分析1000个网织红细胞。结果：两次CP给药后6h即可观察到网织红细胞微核率增高，分别在两次给药后24h达到高峰，此后逐渐下降。应用流式细胞术检测外周血网织红细胞微核与外周血涂片显微镜检测敏感性相同，两者并具有良好的相关性。流式细胞术检测方法具有高通量、省时、省力等优势。结论：在检测化合物遗传毒性方面，流式细胞术检测方法值得推广应用。     

南京“5.7” 192Ir源放射事故患者的生物剂量估算

目的 用3种方法估算南京"5.7" ¹⁹²Ir源放射事故患者的生物剂量,为核与辐射事故受照者的临床救治提供剂量资料。方法 受照后第5天采集患者外周血,分别进行外周血淋巴细胞染色体"双着丝粒+环"("dic+r")畸变分析、胞质分裂阻滞微核(CBMN)分析、核质桥(NPB +FHC)分析,并估算生物剂量。用双着丝粒畸变在细胞间的泊松分布情况检验照射的均匀性。结果3种方法估算的该患者受到的一次全身等效剂量分别为"dic+r"畸变分析1.51 Gy (95% CI 1.40~1.61),CBMN 分析1.47 Gy (95% CI 1.36~1.60),NPB+FHC分析1.30 Gy(95% CI 1.00~1.60)。泊松分布检验结果显示,该患者"dic+r"畸变偏离泊松分布,受到了不均匀照射。结论 外周血淋巴细胞染色体"dic+r"畸变分析、CBMN分析、NPB+FHC分析均是有效的生物剂量估算手段,对本例急性局部不均匀照射患者估算的一次全身等效剂量与临床诊断结果相符。     

Cytogenetic monitoring of hospital staff exposed to ionizing radiation: optimize protocol considering DNA repair genes variability

Purpose: Chronic occupational exposure to ionizing radiation (IR) induces a wide spectrum of DNA damages. The aim of this study was to assess the frequencies of micronucleus (MN), sister chromatid exchanges (SCE) and to evaluate their association with XRCC1 399 Arg/Gln and XRCC3 241 Thr/Met polymorphisms in Hospital staff occupationally exposed to IR.

Materials and methods: A questionnaire followed by a cytogenetic analysis was concluded for each subject in our study. The exposed subjects were classified into two groups based on duration of employment (Group I?<?15 years; Group II ≥15years). The genotypes of all individuals (subjects and controls) were determined by the polymerase chain reaction–restriction fragment length polymorphism (PCR-RFLP).

Results: DNA damage frequencies were significantly greater in IR workers compared with controls (p?<?.05). However, no association arised between XRCC1 399 Arg/Gln and XRCC3 241 Thr/Met polymorphisms, on one hand, and the severity of DNA damages in the studied cohort of Tunisian population, on the other hand.

Conclusion: Our data provide evidence for an obvious genotoxic effect associated with IR exposure and reinforce the high sensitivity of cytogenetic assays for biomonitoring of occupationally exposed populations. These results indicate that workers exposed to IR should have periodic monitoring, along their exposure. The variants, rs25487 and rs861539, of XRCC1 and XRCC3 genes have obvious functional effects. Paradoxically, these variants are not associated with the severity of damages, according to used assays, in the studied cohort of Tunisian population, unlike other studies.     

Radiocontrast media affect radiation-induced DNA damage repair in vitro and in vivo by affecting Akt signalling

Purpose

The study was performed to investigate cytogenetic effects of ionic and non-ionic radiocontrast media (RCM) meglumine, iohexol alone and in combination with irradiation in mouse bone marrow cells in vivo and in vitro.

Materials and methods

Micronuclei assay was performed in bone marrow cells (BMC) of Balb/C mice intraperitoneally injected with RCM in the presence or absence of whole-body irradiation of 50 mGy. DNA repair (NHEJ) signalling and efficiency were analyzed by Western blot and γH2AX-foci assay in normal fibroblast HSF-7 and HUVEC cells.

Results

Both compounds reduced proliferation of BMC significantly. Concentrations of 0.5, 1 and 2 ml/kg meglumine or iohexol significantly enhanced the frequency of micronucleated polychromatic erythrocytes (MnPCEs) at all doses of meglumine (p < 0.01) and 2 ml/kg of iohexol (p < 0.05). Combined with irradiation meglumine at 0.5 and 1 ml/kg led to a higher frequency of MnPCEs than iohexol/IR (p < 0.05). Meglumine induced DNA-double strand breaks (DNA-DSB) in non-irradiated HSF and strongly increased residual DNA-DSB within 10 min to 24 h after irradiation with 200 or 400 mGy (p < 0.001). Iohexol did not induce DNA-DSB but blocked repair of radiation-induced DNA-DSB significantly (p < 0.05). Meglumine blocked IR-induced Akt phosphorylation, phosphorylation of DNA-PKcs (S2056, T2609) and ATM (S1981). Iohexol only blocked phosphorylation of Akt and DNA-PKcs at S2056.

Conclusion

RCM result in clastogenic effects through interference intracellular signalling cascades involved in the regulation of non-homologous end-joining repair of DNA-DSB.