环磷酰胺和异环磷酰胺致突变作用比较研究

目的与方法：本文通过Ａｍｅｓ试验和ＳＯＳ显色试验比较了环磷酰胺（ＣＰ）与异环磷酰胺（ＩＦＯ）的致突变作用。结果：ＣＰ和ＩＦＯ在胡Ｓ９活化的情况下,均可显著增加碱基置换型检测菌株ＴＡ１００的回变菌落数,并呈现明显的剂量－－效应关系,但两药的作用强度不同,同等剂量时ＩＦＯ诱发的回变菌落数均少于ＣＰ,１０００μｇ／皿的剂量下ＣＰ诱导回变菌落数为空白对照的１２倍以上,ＩＦＯ仅为空白对照的５倍左右;在无Ｓ９活化时两药对ＴＡ１００菌株菌落回变均无影响,而对移码突变型检测菌株ＴＡ９７、ＴＡ９８、ＴＡ１０２,两药无论有无Ｓ９活化均对菌落回变无显著影响。ＳＯＳ显色试验则表明,即使在有Ｓ９活化条件下,两药对大肠杆菌ＰＱ３５、ＰＱ３７菌株ＳＯＳ修复系统均无诱导性。结论：ＣＰ和ＩＦＯ都是通过引起ＤＮＡ碱基置换诱导突变,且等剂量条件下Ｉ     

银杏叶提取物致突变性研究

银杏叶乙醇提取物为棕黄色粉末，内含槲皮素１０．３１％，山奈素１０．５０％和异鼠李素３．１９％。银杏叶提取物剂量达７．５ｇ／ｋｇ，小鼠微核试验结果阴性。平板渗入法Ａｍｅｓ试验，剂量在１４．９－１８６２．５ｇ／皿时，ＴＡ９８和ＴＡ９７ａ的回变菌落不论加Ｓ９与否，均有依剂量的增加，加Ｓ９者更甚，且有一个或二个剂量的诱发回谱菌落数超过对照值的两倍，提示ＥＧＢＬ含有移码突变的致突变物，主要是槲皮素的山奈素。     

奥扎格雷钠的致突变作用研究

本文用Ａｍｅｓ试验，微核试验和精子畸形试验对奥扎格雷钠的致突变作用研究，结果表明：①ＯＫＹ－０４６剂量为０．０５、０．５、５、５０、５００μｇ／皿，进行Ａｍｅｓ试验，表明该药未能诱导ＴＡ９８、ＴＡ１００、ＴＡ１０２的回变菌落数增加（ＭＲ〈２）。②ＯＫＹ－０４６药物剂量为３０６．２ｍｇ／ｋｇ，６１２．４ｍｇ／ｋｇ，１２２４．８ｍｇ／ｋｇ时，均不诱发小鼠骨髓嗜多染红细胞的微核率增加。③ＯＫＹ－０４６药     

格兰西隆的致突变性研究

应用Ａｍｅｓ试验，体外染色体畸变试验和微核试验对格兰西隆进行了致突变性研究。研究结果，格兰西隆的各剂量组对ＴＡ９８，ＴＡ９７，ＴＡ１００，ＴＡ１０２在加和不加Ｓ９ｍｉｘ条件下均无致突变性，染色体畸变试验中，在加Ｓ９ｍｉｘ条件下，１５μｇ／ｍｌ和３０μｇ／ｍｌ剂量对ＣＨＬ细胞诱发的畸变率分别为６％和７％，为阳性。以４８ｍｇ／ｋｇ剂量以上对小鼠骨髓多染红细胞有诱发微核作用。实验结果提示，格兰西隆具有潜在致突变性。     

STUDY ON THE MUTAGENIC AND ANTIMUTAGENIC POTEN-TIALS OF GYPENOSIDES(GPS)IN MICE

对绞股蓝总皂甙（ＧＰＳ）的研究表明：急性毒性＞１０００Ｏｍｇ／ｋｇ，各项致突变试验结果均为阴性；在ＧＰＳ剂量为１０００、２５００，５００Ｏｍｇ／ｋｇ时由环磷酰胺所致小鼠骨髓细胞微核率分别为１１．９‰、８．５‰和１３．６‰均较环磷酰胺组的２９．９‰明显降低（Ｐ＜０．０５）。在５－５０μｇ／皿范围内，ＧＰＳ对ＴＡ９８、ＴＡ１００和ＴＡ１０２菌株经不同阳性物诱导后的菌落回变数有不同程度降低，对ＴＡ９８菌株在２－ＡＦ（Ｓ９＋）有良好的抗诱变作用，并呈剂量反应关系。结果提示，绞股蓝总皂甙在体内和体外均表现出明确的抗诱变作用。本文还对其抗诱变作用的可能机理进行了探讨。     

硫双灭多威农药的致突变性研究

本文用微核试验、Ａｍｅｓ试验和精子畸形试验对双灭多威农药的致突变性进行检测，结果表明：（１）硫双灭多威农药剂量为２９．６ｍｇ／ｋｇ，５９．２ｍｇ／ｋｇ和８８．８ｍｇ／ｋｇ时，均不诱发昆明小鼠骨髓嗜多染红细胞的微核增加；（２）对硫双灭多威农药为０．５，５．０，５０，５００，５０００μｇ／Ⅲ进行Ａｍｅｓ试验，结果表明该药未诱导ＴＡ９７、ＴＡ９８、ＴＡ１００和ＴＡ１０２的加菌数增加；（２）硫双灭多威农药     

STUDY ON THE GENOTOXICITY OF 5 HAIR DYES MADE IN CHINA AND THEIR MAIN INGREDIENT P-PHENYIENEDIAMINE

对五种国产染发剂及其主要组份对苯二胺进行了沙门氏菌致突变（Ａｍｅｓ）试验、小鼠骨髓嗜多染红细胞微核试验的研究，探讨其有无遗传毒性。结果发现４种染发剂和其主要组份对苯二胺在有Ｓ９的条件下，对ＴＡ９７、ＴＡ９８均表现出诱变菌落数大于自发回变数的２倍以上，提示染发剂有一定的遗传毒性，并与对苯二胺的存在有关。微核试验仅１种染发剂在２１．６２ｍｇ／ｋｇ时，微核效应率显著高于对照组（Ｕ＝２．６１，Ｐ＜０．０１）。     

五种国产染发剂及其主要组份对苯二胺的遗传毒性研究

对五种国产染发剂及其主要组份对苯二胺进行了沙门氏菌致突变（Ａｍｅｓ）试验、小鼠骨髓嗜多染红细胞微核试验的研究，探讨其有无遗传毒性。结果发现４种染发剂和其主要组份对苯二胺在有Ｓ９的条件下，对ＴＡ９７、ＴＡ９８均表现出诱变菌落数大于自发回变数的２倍以上，提示染发剂有一定的遗传毒性，并与对苯二胺的存在有关。微核试验仅１种染发剂在２１．６２ｍｇ／ｋｇ时，微核效应率显著高于对照组（Ｕ＝２．６１，Ｐ〈０．０１     

14种常用静脉麻醉药物致突变性的Ames试验检测

本文报导了１４种临床常用静脉麻醉药物致突变性的Ａｍｅｓ试验检测结果。实验结果显示，除氯丙嗪（Ｃｈｌｏｒｐｒｏｍａｚｉｎｅ）在本实验剂量下对ＴＡ９８和ＴＡ１００呈强烈抑菌无法得到其致突变性结果外，其余１３种麻醉药物在Ｓ９－时均为诱变阴性，Ｓ９＋时１０种为诱变阴性，３种显弱的致突变作用．０．３１３－１．２５ｍｇ／皿卡肌宁（Ａｔｒａｃｕｒｉｕｍｂｅｓｙｌａｔｅ）和０．６２５－２．５０ｍｇ／皿硫贲妥钠（Ｔｈｉｏｐｅｎｔａｌ）平板掺入对ＴＡ９８（Ｓ９＋）呈诱变阳性，但对ＴＡ１００（Ｓ９＋）不显诱变作用；６．２５－２５．０ｍｇ／皿羟基丁酸钠（Ｓｏｄｉｕｍｈｙｄｒｏｘｙｂｕｔｙｒａｔｅ）平板掺入可使ＴＡ１００（Ｓ９＋）回变菌落数明显增加，但对ＴＡ９８（Ｓ９＋）不显诱变作用，与阳性对照药物２－氨基芴（２－Ａｍｉｎｏｆｌｕｏｒｅｎ）比较。上述３种静脉麻醉药物的致突变性是较弱的。     

多沙唑嗪的致突变作用研究

应用ＣＨＬ细胞染色体畸变试验、Ａｍｅｓ试验 和小鼠骨髓哮多染色细胞微核试验对多沙唑嗪进行了致突变作用研究。结果显示：３１２．５μｇ／皿－５０００μｇ／皿合剂量组ＴＡ９７、ＴＡ９８、ＴＡ１００、ＴＡ１０２等菌株回复突变率未见明显增加；５１３ｍｇ／ｋｇ、１０２５ｍｇ／ｋｇ、２０５０ｍｇ／ｋｇ各剂量组ＰＣＥ微核率分别为１．７‰、２．５‰、２．６‰，与对照组（２．０）‰比较无明显差异（Ｐ〉０．０５）；１０     

Revertants of adenovirus type-12-transformed hamster cells have lost part of the viral genomes.

The cell line T637 was derived from BHK21 cells (subline B3) by transformation with adenovirus type 12. The T637 cells contain multiple copies of the viral DNA, with different parts of the viral genomes being represented in unequal amounts. The persisting viral DNA has been shown in previous work to be covalently linked to cellular DNA. In the present report, the isolation and characterization of 18 morphological revertants of the T637 line are described. The T637 cells are round and epithelioid, the revertants are fibroblasts. The revertants arose spontaneously and could be enriched by letting the T637 culture grow to very high density; the T637 cells detached from the plastic surface, whereas the revertants stayed attached and could then be cloned. The morphological revertants of T637 cells differed from both the B3 and the T637 lines in a number of biological properties, such as saturation density, growth rate, agglutinability by plant lectins and uptake of low-molecular-weight compounds. The revertants were all T-antigen negative, but reacted with anti-LETS serum (antiserum against the large external transformation-sensitive protein). The B3 and T637 cells were LETS-negative. The revertants exhibited a pseudodiploid karyotype. All of the 18 revertants could be transplanted into 4-week-old Syrian hamsters, although most of the revertants grew less rapidly than the B3 cells. The patterns of integration of adenovirus type-12 DNA were investigated using the DNA-DNA hybridization technique of Southern. Some of the revertant lines (TR3, TR7, TR16, and F10) appeared to have lost almost all viral DNA sequences; the other revertant lines lacked several of the viral DNA sequences present in the T637 line. Upon superinfection of the T637 line and all of the revertants with adenovirus type 2 (Ad2), Ad2 replication was inhibited in T637 cells. In the revertants, however, Ad2 grew as efficiently or even more so than in the B3 line.     

Nickel mutagenesis: alteration of the MuSVts110 thermosensitive splicing phenotype by a nickel-induced duplication of the 3' splice site

We investigated DNA damage caused by carcinogenic metals in a murine sarcoma virus (MuSV)-based mutagenicity assay in which mutations targeted to v-mos expression can be selected. Nickel chloride treatment of NRK cells (termed 6m2 cells) infected with MuSVts110, a retrovirus conditionally defective in viral RNA splicing and cell transformation, caused the outgrowth of transformed "revertants" with changes in the MuSVts110 RNA splicing phenotype. Cadmium and chromium treatment of 6m2 cells resulted in the selection of a second class of revertants with what appeared to be frameshift mutations allowing the translation of a readthrough gag-mos protein. In both classes of metal-induced revertants, viral gene expression was distinct from that observed in revertants arising in untreated 6m2 cultures, arguing that metal treatment did not simply enhance the rate of spontaneous reversion. In one representative nickel revertant line the operative nickel-induced mutation affecting MuSVts110 RNA splicing was a duplication of 70 bases surrounding the 3' splice site. The effect of this mutation was to direct splicing to the most downstream of the duplicated 3' sites and concomitantly relax its characteristic thermosensitivity. These data establish the mutagenic potential of nickel and provide the first example of a defined nickel-induced mutation in a mammalian gene.     

荧光染料Hoechst 33342与细胞凋亡

荧光染料Hoechest33342在计数细胞周期及细胞凋亡研究方面得到广泛的应用。研究发现,Hoeehst33342可诱导如BC3H—1细胞、HL-60细胞、HT-144黑色素瘤细胞、肝细胞癌细胞等多种细胞凋亡。Hoeehest33342对拓扑异构酶I活性的抑制、对TATA盒结合蛋白的抑制、细胞内E2F-1蛋白表达的增加和线粒体功能不良可能是其诱导细胞凋亡的主要机制。     

Characterization of mutagenic glucuronide formation from benzo(a)pyrene in the nonrecirculating perfused rat liver

Excretion of mutagenic metabolites of benzo(a)pyrene into bile from livers of corn oil- or 3-methylcholanthrene-treated Sprague-Dawley rats perfused with a nonrecirculating perfusion system was quantitated. Mutagenic benzo(a)pyrene metabolites were detected using Salmonella typhimurium (strain TA 98) grown in the presence of limiting amounts of histidine. Microsomes were not included in the bacterial assay since metabolic activation was carried out by the perfused liver. Mutagenic activity was detected only if beta-glucuronidase was added to the assay mixture or if bile was treated with acid to hydrolyze glucuronides prior to assay. When livers were perfused with 20 microM benzo(a)pyrene, stable, mutagenic glucuronides were exported from corn oil-treated livers at maximal rates of 149 +/- 24 (S.E.) revertants/g/hr and at rates of 225 +/- 22 revertants/g/hr in livers from 3-methylcholanthrene-treated rats. Chromatography of bile by high-performance liquid chromatography demonstrated that two peak areas contained phenolic glucuronides which were hydrolyzed by beta-glucuronidase. These two peaks, one which cochromatographed with authentic 3-benzo(a)pyrenyl-beta-D-glucuronide, accounted for all of the mutagenic activity in bile from livers perfused with benzo(a)pyrene. A good correlation (r = 0.86) between rates of mutagen production and rates of formation of phenolic glucuronides was observed under a variety of experimental conditions. The mutagenic activity observed with pure 3-benzo(a)pyrenyl-beta-D-glucuronide exposed to beta-glucuronidase was 4 revertants/nmol. When the rate of mutagen production was divided by the rate of production of 3-benzo(a)pyrenyl-beta-D-glucuronide by the perfused liver, a value of 4 revertants/nmol was also obtained. Therefore, it is concluded that mutagens exported in bile from livers perfused with benzo(a)pyrene can be accounted for predominantly by hydrolysis products of phenolic glucuronides.     

Activation of the food-derived mutagen 2-amino-1-methyl-6-phenylimidazo[4, 5-b]pyridine by rabbit and human liver microsomes and purified forms of cytochrome P-450

The specificity of rabbit cytochrome P-450 involved in the mutagenicactivation of 2-amino-1-methyl-6-phenylimid-azo[4, 5-b]pyridine(PhIP) was assessed using control and induced rabbit liver andlung microsomes, and six purified forms of cytochrome P-450.The number of revertants produced/2.5µg PhIP by controlrabbit liver was 260 ± 196/10 µg of microsomalprotein (mean ± SD; n = 3), and this increased to 1265± 248 when 2,3,7,8-tetrachloro-dibenzo-p-dioxin (TCDD)-inducedliver microsomes were used as the activation source in the Amestest. Microsomes form phenobarbital-, rifampicin-and acetone-pretreatedrabbits showed no increase in activity over controls. Controllung microsomes did not activate PhIP to a mutagen, whereasTCDD-induced lung microsomes produced 1443 ± 136 (mean± SD; n=4) Ames/Salmonella revertants/100 µg protein.In reconstitution experiments cytochrome P450 forms 4 and 6were found to be efficient activators of PhIP to a mutagen.Form 6 was 3.1-fold more active than form 4 and produced 4577revertants/10 pmol with a 20-min preincubation step in the Amestest. Cytochrome form 5 produced 17 revertants/10 pmol and forms2, 3b and 3c were not active in metabolizing PhIP to a mutagen.A highly significant statistical correlation existed betweenthe capacity of control and induced liver microsomes to activatePhIP to a mutagen and their cytochrome P-450 form 4 (r = 0.97,r² = 0.94) and form 6 (r = 0.95, r² = 0.90) content. These datastrongly support the involvement of polycyclic hydrocarbon-inducibleforms of cytochrome P450 in the activation of PhIP in the rabbit.Anti-rabbit forms 4 and 6 IgGs recognized proteins in sevenhuman liver microsomes of comparable mol. wt to rabbit cytochromeP-450 forms 4 and 6. However, no correlation existed betweenthe content of these proteins and the capacity of human livermicrosomes to activate PhIP.     

Effect of microsomal enzyme inducers on the urinary excretion pattern of mutagenic metabolites of the carcinogen 2,4-toluenediamine

2,4-Toluenediamine [(TDA) CAS: 95-80-7] was administered to rats pretreated with the microsomal enzyme inducers phenobarbital (PB), beta-naphthoflavone (beta NF), or 3-methylcholanthrene (MCA). The 24-hour urines of male F344 rats were examined for their mutagenic potency by means of the Salmonella assay, with the Aroclor 1254-pretreated rat liver S-9 fraction as an activating system. No revertants were found with TDA or its urinary metabolites in the absence of the S-9 fraction. In the presence of S-9, the number of revertants increased as the concentration of TDA or its urinary metabolites increased. The urinary metabolites, generated after the microsomal enzyme inducers (PB, beta NF, MCA), had increased mutagenic activity as compared with the controls (saline, corn oil). In the presence of beta-glucuronidase (beta G), increased numbers of TA98 revertants were noted in the urine of rats pretreated with PB, saline, or corn oil. Addition of sulfatase did not alter the number of TA98 revertants. Conversely, beta G treatment of urine from rats pretreated with MCA or beta NF led to a decrease in the number of TA98 revertants as compared to levels in urine without beta G. Addition of known urinary metabolites of TDA, such as 4-acetylamino-2-aminobenzoic acid or 2,4-diacetylaminobenzoic acid, to beta NF-pretreated rat urine had no inhibitory effect on the mutagenicity in the absence of beta G. However, in the presence of beta G, the inhibitory effect was similar to that noted with beta NF-pretreated rat urine. Upon separation of urinary metabolites (beta NF-pretreated rat urine) into free, conjugated, and water-soluble forms, the maximum number of TA98 revertants was associated with the free ethyl acetate-extractable fraction, which accounted for the total mutagenic activity associated with the original volume of urine. Conjugated metabolites showed much less mutagenic activity, and an inhibitory principle was associated with the water-soluble fraction.