镉和氯化汞致体细胞hprt基因位点突变的作用和突变频率的研究

目的 了解镉和汞对细胞hprt基因位点的影响，探讨化学诱变物致机体损伤早期检测的敏感指标。方法 采用多核细胞法研究化学诱变物氯化汞和镉对人血淋巴细胞hprt基因位点的影响及突变频率。结果 氯化汞可诱发大鼠血淋巴细胞hprt基因位点突变，突变频率随着染毒浓度的增加而升高，突变频率Y↑^（10^-3)与氯化汞浓度C（mg/kg)之间拟合成Y↑^=0.0423C 1.0463的直线回归方程，不同浓度金属镉也能致hprt基因突变，镉浓度与突变频率之间有剂量反应关系。结论 氯化汞和镉对血淋巴细胞hprt基因位点及突变频率有影响，hprt基因突变频率可作为接触环境致突变物人群检测的敏感指标。     

醋酸铅体外诱发人外周血淋巴细胞HPRT基因位点突变的研究

目的 了解醋酸铅对人外周血淋巴细胞HPRT基因位点的影响,以探讨铅的致突变性。方法 采用多核细胞法体外研究醋酸铅对人外周血淋巴细胞HPRT基因位点的影响及突变频率。结果 0．25mmol/L醋酸铅即可诱发人外周血淋巴细胞HPRT基因位点突变,且突变频率随着染毒浓度的增加而升高,突变频率Y(10^-3)与醋酸铅浓度C(mmol/L)之间存在一定的剂量-效应关系,直线方程分别为：Y=1．0566 0．1661C(r=0．9582)和Y=1．0762 0．1987C(r=0．9434)。结论 在一定条件下,醋酸铅对人外周血淋巴细胞HPRT基因位点及突变频率有影响,HPRT基因突变频率可望成为接触环境致突变物人群检测的敏感指标。     

氯化汞诱发人离体血细胞hprt基因位点突 变频率的研究

为了解化学诱变物对血细胞hprt基因位点的影响。采用多核细胞法（CB法）研究了不同浓度氯化汞对人血淋巴细胞hprt基因位点的影响及突变频率。结果表明：50μg/ml以下的氯化汞可诱发人淋巴细胞hprt基因位点突变,且突变频率随着体外染毒浓度的增加而升高,突变频率Y(10∧－3）与氯化汞的浓度C之间可以拟合成Y＝0．9948＋0．0106C的直线回归议程。hprt基因突变频率可作为检测生产性毒物或环境毒物接触人群的敏感指标。     

晚期混合裂变产物内照射诱发体细胞HPRT基因位点突变率与剂量率关系的研究

运用多核细胞法及胞质分裂阻断微核（CBMN）法对5组Wistar雄性大鼠外周血淋巴细胞HPRT基因位点突变频率及微核进行检测。实验组注射不同放射性比活度的晚期混合裂变产物，在达到累积剂量近似相等（约4.66cSv）时心脏穿刺取血。结果显示，在总累积剂量近似相等条件下，HPRT位点突变频率、微核细胞率、微核率均随剂量率的增加而增加，4个剂量率点间的HPRT位点突变频率、微核细胞率和微核率总体上均有显著差异（P＜0．01）。HPRT基因位点突变频率、微校率与剂量率之间的关系可分别用函数Y=a＋blnX表示。HPRT位点突变频率与微核率间存在线性相关。     

放射性核素内照射诱发体细胞HPRT基因突变

[目的] 研究放射性核素内照射诱发大鼠外周血淋巴细胞次黄嘌呤乌嘌呤磷酸核糖转移酶(HPRT)基因位点突变及其剂量-效应关系.并比较多核细胞法和5-溴脱氧尿嘧啶核苷(5-Brdurd)法测定HPRT基因位点突变的检出率.[方法] 用多核细胞法和Brdurd法研究的两批大鼠均分别随机分为1个对照组和4个不同剂量组,每组6只.对照组尾静脉注射生理盐水(pH 3.0),注射容积为0.5 ml/100 g体重,注射后1 d心脏穿刺取血.多核细胞法的不同剂量实验组大鼠尾静脉注射比活度为3.64×105 Bq/ml放射性晚期混合裂变产物,注射容积同对照组,于注射后1、3、6和9 d心脏穿刺取血.Brdurd法的不同剂量实验组大鼠尾静脉注射比活度为3.40×105 Bq/ml的放射性晚斯混合裂变产物,注射容积同前,于注射后1、5、15和20 d心脏穿刺取血.每鼠分别取抗凝血1.5 ml于离心管中,加入Hanks液8 ml,混匀后1 500 r/min离心10 min,去上清后再重复洗涤一次.将沉积细胞悬浮于生长培养液(内含90%RPMI1640,10%灭活小牛血清,庆大霉素100 IU/ml,PHA适量)中至1.5 ml,取上述血细胞0.5 ml接种于4.5 ml生长培养液中.每个样本培养2瓶,其中1瓶加入6-巯基乌嘌呤(6-TG).终浓度为1×10-5 mol/L.①多核细胞法将样本置于(38.2±0.3)℃培养56 h,加入细胞松弛素-B(Cyt-B),终浓度为6 μg/ml,再继续培养至96 h.培养物离心、固定、制片.每个样本计数6 000个转化的淋巴细胞(其中加与不加6-TG各计数3 000个),统计其中双核或多核淋巴细胞数.将含有6-TG样本的1 000个转化的淋巴细胞中双核或多核淋巴细胞数除以不含有6-TG样本的1 000个转化的淋巴细胞中双核或多核淋巴细胞数,所得结果则为HPRT基因位点突变率(‰).并用计算机拟合剂量-效应关系模型.②Brdurd法将样本置于(38.2±0.3)℃培养24 h后,加入250 μg/ml Brdurd 0.1 ml,避光培养48 h.培养物离心、固定、制片.空气干燥后用Hoechst 33258染色30 min,再进行Giemsa染色.不加6-TG样本计数转化及未转化的淋巴细胞3 000个.加6-TG样本计数全部突变的淋巴细胞数.并按下式计算淋巴细胞转化率和HPRT基因突变率淋巴细胞转化率=(转化的淋巴细胞数/3 000个转化及未转化淋巴细胞)×100%;HPRT基因突变率=(突变淋巴细胞数/0.5 ml外周血淋巴细胞数×淋巴细胞转化率).[结果] 随着放射性核素内照射剂量的增加,HPRT基因位点突变率增加.用多核细胞法检测的放射性核素内照射诱发的淋巴细胞HPRT基因位点突变率(y,‰)与累积剂量(D,cSv)相关模型为y=1.149 8+0.119 9 InD,r=0.970 6;用Brdurd法检测的放射性核素内照射诱发的淋巴细胞HPRT基因位点突变率(y,‰)与累积剂量(D,cSv)相关模型为y=6.531 0×10-2+3.454 2×10-3D,r=0.984 6.多核细胞法检测HPRT基因突变的检出率比Brdurd法高11～17倍之多.[结论] 淋巴细胞HPRT基因对电离辐射敏感.本文研究的辐射剂量范围内,辐射诱发淋巴细胞HPRT基因位点突变率与照射剂量呈正相关.多核细胞法对HPRT基因位点突变的检出率高于Brdurd法.     

多核细胞法和Brdurd法检测辐射诱发体细胞HPRT基因突变的比较研究

目的　研究放射性核素内照射诱发体细胞HPRT基因位点突变及其剂量 -效应关系 ,比较不同方法对HPRT基因位点突变的检出率。方法　给大鼠尾静脉注射晚期混合裂变产物后不同时间心脏穿刺取血。用多核细胞法和Brdurd法分别检测HPRT基因突变细胞 ,计算突变率 ,拟合出辐射诱发HPRT基因位点突变的剂量 -效应关系函数。结果　用多核细胞法检测的放射性核素内照射诱发HPRT基因位点突变率 (y ,‰ )和剂量 (D ,cSv)相关函数为y =1 14 98+0 1199lnD,r =0 970 6 ;用Brdurd法检测的相关函数为 y =6 5 310× 10 -2 +3 4 5 4 2× 10 -3 D ,r =0 984 6。多核细胞法检测HPRT基因位点突变检出率比Brdurd法高 11～ 17倍之多。结论　体细胞HPRT基因对电离辐射敏感 ,有可能作为辐射生物剂量计。多核细胞法对HPRT基因突变检出率高于Brdurd法     

辐射诱发外周血淋巴细胞HPRT基因位点突变的研究进展

在分析和定量辐射诱发体细胞基因突变增高的方法中,应用最广的是抗6-巯基鸟嘌呤(6-thioguanine resistance,6-TG)突变分析,用于检测次黄嘌呤鸟嘌呤磷酸核糖转移酶(Hypoxanthine-guanine phosphoribosyl transgerase,HPRT)基因位点的突变.近年来,国内外均对辐射诱发的外周血淋巴细胞HPRT基因位点突变进行了广泛而深入的研究.本文对国内外关于辐射诱发外周血淋巴细胞HPRT基因位点突变的研究情况进行了综述.     

氡及其子体诱发大鼠体细胞HPRT基因位点的突变

[目的]用多核细胞法研究氡及其子体诱发大鼠外周血淋巴细胞和气管-支气管上皮细胞的次黄嘌呤鸟嘌呤磷酸核糖转移酶(HPRT)基因位点突变情况。[方法]Wistar雄性大鼠24只,采用HD-3型多功能移动式氡室进行动态吸入染毒,按照氡染毒的累计暴露量,分为3个实验组和1个对照组;获取大鼠外周血淋巴细胞和气管-支气管上皮细胞,以多核细胞法检测该两种细胞的HPRT基因突变频率。[结果]大鼠外周血淋巴细胞和气管-支气管上皮细胞的HPRT基因突变频率均随氡累积暴露剂量的增加而相应增加,剂量-效应关系明显,拟合的函数分别为(?)=1.785×10~(-5)D~2 1.174×10~(-3)D 1.054和(?)=3.538×10~(-5)D~2 8.338×10~(-4)D 1.032。[结论]氡及其子体能诱发大鼠外周血淋巴细胞和气管-支气管上皮细胞的HPRT基因突变,呈现一定的剂量-效应关系。     

15名工业探伤人员染色体畸变分析

近年来新近发展起来的次黄嘌呤一鸟嘌呤转磷酸糖基酶位点(HPRT)检测是一种快速、灵敏测定人体细胞突变的方法,人体外周血淋巴细胞中抗6-硫代鸟嘌呤(6-TG)突变体是在HPRT基因位点上的突变细胞,具有稳定的6-TG表型。当胞体中HPRT基因改变时,通过检测人体外周血中抗6-TG细胞出现的频度,就可确定体细胞的突变频度。     

检测人外周血淋巴细胞抗6—TG突变的方法学问题

本文就人外周血淋巴细胞抗6-TG突变体测定的方法学问题做了介绍。淋巴细胞抗6-TG突变体具有稳定的抗6-TG表型,胞内缺乏次黄嘌呤-鸟嘌吟转磷酸核糖基酶(HPRT),HPRT基因存在结构改变。血样经冷冻预处理或使用流式细胞光度术时,放射自显影法所测结果与克隆检测法相似,正常成人血淋巴细胞抗6-TG突变率为10~(-6)～10~(-5),肿瘤病人接受化疗或放疗后该值升高。抗6-TG细胞测定反映了人体内特殊基因位点的突变频率,是体内体细胞突变的良好指标。     

放射性核素内照射诱发大鼠脾淋巴细胞的HPRT基因突变

目的探讨克隆法研究放射性核素内照射诱发大鼠脾淋巴细胞HPRT基因突变的可行性。方法大鼠尾静脉注入晚期混合裂变产物,克隆法检测不同累积剂量和不同剂量率的内照射诱发的脾淋巴细胞HPRT基因突变,拟合剂量-效应方程。结果随着累积剂量和剂量率的增加,HPRT基因突变频率随之上升,剂量-效应关系和剂量率-效应关系均符合线性平方模型,分别为：y=4．5060 0．5635D 0．0606D^2,y=2、6638 0．5177D-0．0008D^2。结论克隆法是一种敏感的检测辐射诱发HPRT基因突变的方法,脾淋巴细胞的HPRT基因突变对辐射敏感。     

DNA lesion and Hprt mutant frequency in rat lymphocytes and V79 Chinese hamster lung cells exposed to cadmium

Cadmium is a potential carcinogenic environmental and occupational pollutant. A wide variety of mutagens have been shown to cause DNA damage, but it is not yet clear whether the DNA damage is relative to inducement of mutations. DNA damage and the formation of mutations at the hypoxanthine guanine phosphoribosyl trans ferase (HPRT) induced by cadmium chloride (CdCl(2)) were investigated with rat lymphocytes and V79 Chinese hamster lung cells. The hprt mutant frequency (MF) assay was used as the method to measure gene mutation in the rat lymphocytes and V79 cells exposed to CdCl(2), and comet assay analysis was performed to detect DNA lesion and repair in CdCl(2)-induced V79 cells. The results showed that CdCl(2) treatment caused a strong genotoxic effect and a marginal effect on the frequency of gene mutations. The hprt mutant frequencies in the rat lymphocytes and V79 cells exposed to CdCl(2) were statistically higher than those of the negative control. There was statistical significance in TL, TD and percentage of comet cell with tails. CdCl(2) treatment can induce DNA single-strand breaks. There was a dose-dependent increase between CdCl(2) and DNA lesion. After cells were treated with CdCl(2) and hydrogen peroxide (H(2)O(2)), the TL and TD declined with repair time increasing, which indicated that DNA damages were repaired gradually. However, DNA repair with treatment of CdCl(2) was slower than that of H(2)O(2) in V79 cells, which suggests that CdCl(2) affected DNA repair of damaged cells. The study also showed that the hprt MF and comet assay can be used for genotoxicity testing of heavy metals. DNA damage detected with the comet assay may be relative to mutagenesis.     

HPRT mutations in lymphocytes from 1,3-butadiene-exposed workers in China

BACKGROUND: 1,3-Butadiene (BD) is an important industrial chemical and an environmental and occupational pollutant. The carcinogenicity of BD in rodents has been proved, but its carcinogenic and mutagenic molecular mechanism(s) are not fully elucidated in humans. OBJECTIVES: In the present study, we compared the mutation frequencies and exon deletions of BD-exposed workers with that of control subjects in China to identify the characteristic mutations associated with BD exposure in the human HPRT (hypoxanthine-guanine-phosphoribosyltransferase) gene. METHODS: Seventy-four workers exposed to BD via inhalation and 157 matched controls were evaluated in Nanjing, China. Molecular analysis of HPRT mutant T lymphocytes from BD-exposed workers and nonexposed control subjects was conducted to identify changes in the structure of the HPRT gene. A total of 783 HPRT mutants were analyzed by multiplex polymerase chain reaction, in which 368 HPRT mutants were isolated from BD-exposed workers and 415 mutants from control subjects. RESULTS: The BD-exposed workers showed a higher mutation frequency (18.2 +/- 9.4 x 10(-6)) than the control subjects (12.7 +/- 7.3 x 10(-6)), but the difference was not significant (p > 0.05). The frequency of exon deletions in BD-exposed workers (27.4%) was significantly higher than that in control subjects (12.5%) (p < 0.05), which mainly included multiplex exon deletions (2-8 exons). CONCLUSIONS: The results of the present study suggest that BD should increase the frequency of large deletions of HPRT gene in human lymphocytes This change confirms and supports the previous findings in BD-exposed workers.     

镉的免疫毒性与促肾上腺皮质激素释放因子的关系

对ＣｄＣｌ２和ＣｄＣｌ２＋α－ｈＣＲＦ（α螺旋促肾上腺皮质激素释放因子）分另染毒的ＳＤ大鼠,用「＾３ＨＴｄＲ」掺入法测定大鼠脾Ｔ、Ｂ淋巴细胞增殖转化功能,垂体前叶细胞培养法测定中枢下丘脑和外周血浆中的ＣＲＦ含量。结果表明单独染镉组有丝分裂原诱导的鼠脾Ｔ、Ｂ淋巴细胞增殖转化均受到显示抑制,具有剂量－效应关系（Ｐ〈０．０５）;动物下丘脑ＣＲＦ含量着染镉剂量升高（Ｐ〈０．０５）;外周血浆ＣＲＦ含量各组间     

镉对大鼠睾丸生精细胞凋亡的影响及锌的保护作用

为探讨对镉对睾丸结构和功能损害及锌对其保护作用的分子机制,研究镉对生精细胞凋亡的影响和锌的保护作用,选用２月龄Ｗｉｓｔａｒ雄性大鼠２４只,均分为染镉组、镉加锌组和对照组,分别自腹腔注射氯化镉（２ｍｇ／ｋｇＢＷ）,注射氯化镉同时及其前后２ｈ各注射醋酸锌一次和等量生理盐水,７ｄ后采用原位缺口平移技术（ＩＮＳＴ）检测各组睾丸生精细胞凋亡数目的变化。结果显示与对照组相比,染镉组大鼠睾丸生精细胞凋亡数目明显     

Effects of 2.45 GHz electromagnetic fields with a wide range of SARs on bacterial and HPRT gene mutations

Present day use of mobile phones is ubiquitous. This causes some concern for human health due to exposure to high-frequency electromagnetic fields (HFEMF) from mobile phones. Consequently, we have examined the effects of 2.45 GHz electromagnetic fields on bacterial mutations and the hypoxanthine-guanine phosphoribosyl transferase (HPRT) gene mutations. Using the Ames test, bacteria were exposed to HFEMF for 30 min at specific absorption rates (SARs) from 5 to 200 W/kg. In all strains, there was no significant difference in the frequency of revertant colonies between sham exposure and HFEMF-exposed groups. In examination of mutations of the HPRT gene, Chinese hamster ovary (CHO)-K1 cells were exposed to HFEMF for 2 h at SARs from 5 to 200 W/kg. We detected a combination effect of simultaneous exposure to HFEMF and bleomycin at the respective SARs. A statistically significant difference was observed between the cells exposed to HFEMF at the SAR of 200 W/kg. Cells treated with the combination of HFEMF at SARs from 50 to 200 W/kg and bleomycin exhibited increased HPRT mutations. As the exposure to HFEMF induced an increase in temperature, these increases of mutation frequency may be a result of activation of bleomycin by heat. We consider that the increase of mutation frequency may be due to a thermal effect.