bluuebunny/crossref_metadata_2025 huggingface dataset:
Synthesis and Structural Characterisation of Copper(II) 15‐Metallacrown‐5 Complexes with PbII, HgII, AgI, NaI and YIII Central Metal Ions
Authors: Seda Sabry Hamed , Janczak Jan , Lisowski Jerzy
Published: February 2007

The new copper(II) 15‐metallacrown‐5 complexes with the central metal ions PbII, HgII, AgI, NaI and YIII, with the formula [MCu5L5]Xn {H2L is 2‐picolinehydroxamic acid or (S)‐phenylalaninehydroxamic acid and X– is NO3– or Cl–}, have been synthesised and characterised by NMR and UV/Vis spectroscopy, electrospray mass spectrometry and elemental analysis. The PbII‐ and HgII 15‐metallacrown‐5 complexes were obtained in the crystalline form as pyridine adducts [PbCu5(picha)5(py)6](NO3)2·3(py) and [HgCu5(picha)5(py)7](NO3)2·2(py) and their X‐ray crystal structures were determined. In both complexes, each peripheral CuII ion of the metallacrown is coordinated by one pyridine molecule bonded in the axial position. In the case of the PbII derivative, one additional axial pyridine molecule is bound to the central metal ion, while in the case of the HgII derivative, two axial pyridine ligands are bound to the central HgII ion. The relative stability of the copper(II) 15‐metallacrown‐5 complexes with various central metal ions was determined on the basis of competition reactions. The relative preference of the 15‐metallacrown‐5 system for the central metal ion follows the series NaI, AgI < lanthanide(III), HgII < PbII.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Synthesis and Structural Characterisation of Diorganotin(IV) and Diphenyllead(IV) Complexes of Pyrimidine‐2‐thionate Derivatives
Authors: Rodríguez Antonio , Sousa‐Pedrares Antonio , García‐Vázquez J. Arturo , Romero Jaime , Sousa Antonio , Russo Umberto
Published: February 2007

The reaction between the ligands 4‐(trifluoromethyl)pyrimidine‐2‐thione (4‐CF3pymSH) and 6‐methyl‐4‐(trifluoromethyl)pyrimidine‐2‐thione (6‐Me‐4‐CF3pymSH) and the corresponding diorganotin(IV) dichloride [R2SnCl2] (R = Me, tBu or Ph) or diphenyllead(IV) dichloride in the presence of triethylamine yields the diorganotin(IV) complexes [R2Sn(4‐CF3pymS)2] and [R2Sn(6‐Me‐4‐CF3pymS)2] or diorganolead(IV) complexes [Ph2Pb(4‐CF3pymS)2] and [Ph2Pb(6‐Me‐4‐CF3pymS)2], respectively. The compounds have been characterised by microanalysis, mass spectrometry and by IR and Mössbauer spectroscopy and, in the case of the compound that was sufficiently soluble, by 1H, 13C, 119Sn and 207Pb NMR spectroscopy. The compounds [Me2Sn(4‐CF3pymS)2] (1), [Ph2Sn(4‐CF3pymS)2] (2), [Ph2Sn(6‐Me‐4‐CF3pymS)2] (5), [tBu2Sn(6‐Me‐4‐CF3pymS)2] (6), [Ph2Pb(4‐CF3pymS)2] (7) and [Ph2Pb(6‐Me‐4‐CF3pymS)2] (8) have also been characterised by X‐ray diffraction. The X‐ray crystal structures show that the metal centre in all these complexes is in a distorted octahedral environment with bonds to two carbon atoms from the aryl or alkyl substituents and to sulfur and heterocyclic nitrogen atoms from the pyrimidine derivative, which acts a (κ2‐N,S) chelating ligand. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Method for selecting exposure levels for the Drosophila sex‐linked recessive lethal assay
Authors: Thompson E. D. , Reeder B. A.
Published: February 2007

The use of the Drosophila sex‐linked recessive lethal assay for detecting mutagenicity of chemicals is well established. When compounds are tested by feeding adult flies, the National Toxicology Program protocol specifies a 3‐day feeding regimen at an exposure level that produces about 30% mortality. Uptake of the test compound is monitored by feeding behavior, amount of excretion, or abdomen size (Woodruff et al: Environ Mutat 7:677–702, 1985). An alternate method for determining uptake is to add radiolabeled sucrose to the feeding solution and then to determine the amount of radioactivity in the flies (Gollapudi et al: Mutat Res 144:13–17, 1985). We have found that the addition of radiolabeled sucrose underestimates consumption for feeding exposures longer than 24 hr because sucrose is metabolized and as much as 30% of the label is excreted, presumably as 14CO2 or 3H2O. Here we describe a method for determining uptake of chemicals by adding 14C‐leucine to the feeding solution. The incorporation of 14C‐leucine is essentially linear over the 3‐day feeding period, which permits accurate estimates of food consumption. Use of this method demonstrates that lower exposure levels of a chemical that do not produce mortality actually results in higher consumption by the flies. The method is proposed as a prescreen to select the appropriate exposure level for the sex‐linked recessive lethal assay.
Effects of cigarette smoking and solvent exposure on sister chromatid exchange frequency in painters
Authors: Kelsey Karl T. , Wiencke John K. , Little Frederic F. , Baker Edward L. , Little John B.
Published: February 2007

A cross‐sectional study of sister chromatid exchange frequency (SCE) in peripheral blood lymphocytes from 117 members of the International Brotherhood of Painters and Allied Tradesman was conducted in union locals in two major U.S. cities. Chronic solvent exposure intensity and duration were estimated from interviewer‐administered‐questionnaire data. SCE for all of the workers in the study were scored by one reader. A second reader determined the SCE frequency from a random sample of 30 workers. No significant difference in SCE frequency was associated with reader or time of reading. Age, coffee and alcohol intake and chronic solvent exposure (both intensity and duration, estimated over the working lifetime and over the year prior to study for each worker) did not significantly elevate SCE. The effect of smoking on SCE frequency, assessed by analysis of variance controlling for other possible confounding factors, showed that smoking increased SCE frequency (P < .0001). The SCE frequency in the smoking, solvent‐exposed (estimated as lifetime exposure) painters was 6.75 SCE/cell; in the non‐smoking, solvent‐exposed workers the SCE frequency was 5.73 SCE/cell; the controls had SCE levels of 6.84 SCE/cell (smokers) and 5.90 SCE/cell (non‐smokers), respectively. These observations are consistent with other work suggesting that chronic solvent exposure in the paint trade is not associated with an elevation in SCE in peripheral blood lymphocytes. However, further work is necessary to address adequately the question of the genotoxicity of acute solvent exposure in these workers.
Reactivity of catecholamines and related substances in the mouse lymphoma L5178Y cell assay for mutagens
Authors: McGregor Douglas B. , Riach Colin G. , Brown Alison , Edwards Ian , Reynolds Deborah , West Katrine , Willington Sarah
Published: February 2007

Using the L5178Y mouse lymphoma cell thymidine kinase locus and the Salmonella his locus assays, the mutagenic potentials of several catecholamines and related compounds were examined. No supplementary metabolic activation systems were used. In the mouse lymphoma assay, the dihydroxybenzenes catechol and hydroquinone had similar and appreciable mutagenic potentials, whereas resorcinol was less active. Derivatives of catechol, such as dopamine and epinephrine, were mutagenic, whereas the related monohydroxylated compounds tyramine and synephrine were inactive. The primary amine, arterenol, and the corresponding secondary amine, epinephrine, induced similar mutagenic responses. Carboxylation of the side chain of dopamine, giving L‐dopa, reduced the maximum mutagenic response. The introduction of charged groups directly on to the aromatic ring also reduced mutagenic activity, while an intervening methylene reversed this effect. Thus, 3,4‐dihydroxyhydrocinnamic acid was more active than 3,4‐dihydroxybenzoic acid. The compound active at the lowest doses was 4‐tert‐butyl catechol. The activities of these compounds are highly dependent upon substituent groups. Experiments with superoxide dismutase gave circumstantial evidence for some of the mutagenic activity being due to superoxide anion. Active oxygen species might be responsible for some of the observed effects, but this cannot be concluded from the superoxide dismutase experiments. Mutagenic responses in Salmonella were very low but were significant for L‐dopa in three strains and for epinephrine and arterenol in one strain. Limited DNA association studies of 14C‐dopamine suggest interactions in L5178Y and Salmonella cells and in mouse liver. The mutagenicity of dopamine in L5178Y is reduced by high serum concentrations during the exposure period, while the apparent association with DNA is unaffected.
Absence of cinoxacin‐induced DNA fragmentation and mutations in the rat granuloma pouch
Authors: Pino Albiana , Maura Annalisa , Grillo Patrizia
Published: February 2007

The mutagenic and DNA‐damaging activities of cinoxacin were evaluated in the rat granuloma pouch assay (GPA) in order to assess its genotoxic potential in vivo. High doses of this antimicrobial quinolone, either directly injected into the pouch or administered by gavage, did not induce mutation at the hgprt locus or DNA fragmentation in granuloma cells. Moreover, DNA damage was absent in the liver and kidney of rats given cinoxacin by the oral route.
Mutagenicity of urine from mice exposed orally to nitrite and various aminated antiparasitic drugs
Authors: Alba M. Arriaga , Aguirre J. Espinosa , Ramírez J. , Cortinas de Nava C.
Published: February 2007

Mutagenic N‐nitroso compound formation from the in vitro reaction of amebicides and anthelmintic drugs, which are pyrimidine derivatives or contain secondary aliphatic amines or heterocyclic nitrogens, has been previously described (Arriaga Alba et al.: Environmental and Molecular Mutagenesis 12:65–73, 1988). Under similar conditions, antiparasitic drugs containing halogenated derivatives of tertiary amines or quaternary ammonium salts do not form mutagenic nitrosated compounds. In the present study the mutagenic activity of mouse urine was determined after oral administration of sodium nitrite and the two above‐mentioned groups of drugs (pyrantel pamoate, chloroquine, piperazine anddehydroemetine/iodochlorhydroxyquin and bephenium hydroxynaphthoate, respectively). Results show that the simultaneous administration of piperazine or chloroquine with sodium nitrite produced urinary mutagens that appeared conjugated as glucuronides, whereas pyrantel pamoate and dehydroemetine in the presence of nitrite caused only slightly mutagenic urine. No mutagenic activity was detected in the urine of mice to which halogenated derivatives of tertiary amines (iodochlorhydroxyquin) or quaternary ammonium salts (bephenium hydroxynaphthoate) were administered together with nitrite.
Mutagenicity of some alkyl nitrites used as recreational drugs
Authors: Dunkel Virginia C. , Rogers‐Back Andrea M. , Lawlor Timothy E. , Harbell John W. , Cameron Thomas P.
Published: February 2007

When the AIDS epidemic was in its earliest stages, and prior to identification of HIV as the etiological factor, the use of volatile nitrites by the male homosexual community to enhance sexual activities appeared to have a significant role in this disease. Preliminary observations indicated that that portion of the male homosexual community which developed Kaposi's sarcoma were also heavy nitrite users. These nitrites had been demonstrated to be mutagenic in bacteria and thus it was postulated that they could be responsible for the appearance of the sarcoma. To evaluate further the genotoxic activity of these chemicals, six nitrites, including those most commonly used by homosexuals for sexual gratification, were selected for testing in the mouse lymphoma TK +/− and Salmonella typhimurium mutagenicity assays. One chemical, n‐amyl nitrite, was negative in the mouse lymphoma assay, while the other five chemicals, n‐butyl, isobutyl, iso‐amyl, sec‐butyl, and n‐propyl nitrite, were positive. All six compounds were positive in the Salmonella assay. The mutagenic and known toxic effects of these chemicals remain a concern because a large population of teenagers and young adults continue to abuse these substances.
Genotoxicity studies with Cuman L in Drosophila melanogaster
Authors: Hemavathy K. C. , Krishnamurthy N. B.
Published: February 2007

Cuman L, a dithiocarbamate fungicide, was tested for its ability to induce sex‐linked recessive lethals (SLRLs) and II‐III chromosome translocations in Drosophila melanogaster by the larval feeding method. The three concentrations of Cuman L, of 20, 40, and 60 μl/100 ml, induced significant (P<0.01) increases in SLRLs but failed to induce any translocations.
Genotoxic activity of benomyl in different test systems
Authors: Georgieva V. , Vachkova R. , Tzoneva M. , Kappas A. , Morgan W. F.
Published: February 2007

Benomyl (methyl‐1‐[butylcarbamoyl]‐2‐benzimidozole carbamate), a benzimidazole derivative fungicide, was tested in the Ames test for point mutations; in human lymphocyte cultures for cell division disturbances, chromosomal aberrations, and SCE; in rat bone marrow cells in vivo for micronuclei; and in rats in vivo for dominant lethals. Benomyl was negative in the Ames test. In human lymphocytes, benomyl at concentrations of 0.5, 1.0, and 2.0 μg/ml decreased the number of cells undergoing third division whereas at the concentrations of 0.25 to 4.0 μg/ml it strongly increased the number of aneuploid cells. Benomyl was also shown to induce sister chromatid exchanges and micronuclei but not chromosome aberrations. Benomyl decreased the number of female rats with implants but did not cause any dominant lethals.
Review of the mutagenicity of ethylene oxide
Authors: Dellarco Vicki L. , Generoso Walderico M. , Sega Gary A. , Fowle John R. , Jacobson‐Kram David , Brockman H. E.
Published: February 2007

Ethylene oxide has been shown to be on effective mutagen in a variety of organisms ranging from bacteria to mammalian cells. There is also an association between ethylene oxide exposure and human somatic cell cytogenetic damage. Furthermore, ethylene oxide has been shown to alkylate protein and DNA at exposure levels that have been encountered occupationally. Ethylene oxide is not only effective at producing somatic cell mutations but also at inducing genetic damage in germ cells. While it is clear that ethylene oxide is a germ cell mutagen in whole mammals, the mechanism(s) by which it produces genetic lesions in germ cells is uncertain.
Induction of gastrointestinal tract nuclear anomalies in b6c3f1 mice by 3‐chloro‐4‐(dichloromethyl)‐5‐hydroxy‐2[5h]‐furanone and 3,4‐(dichloro)‐5‐hydroxy‐2[5h]‐furanone, mutagenic byproducts of chlorine disinfection
Authors: Daniel F. B. , Stober J. A. , Olson G. R. , Galloway S. M.
Published: February 2007

Two chlorinated hydroxylated furanones, 3‐chloro‐4‐(dichloromethyl)‐5‐hydroxy‐2[5H]‐furanone (MX) and 3,4‐(dichloro)‐5‐hydroxy‐2[5H]‐furanone (MA), are bacterial mutagens and they are also byproducts of chlorine disinfection, and frequent contaminants of drinking water. In this work MX is shown to induce nuclear anomalies in the gastrointestinal tract of the B6C3F1 mouse. The other chlorohydroxy‐furanone, MA, gives suggestive evidence of activity. In this bioassay MX was approximately equivalent in potency to epichlorohydrin (ECH) but was much less potent than methylnitrosourea (MNU). The latter two chemicals are confirmed rodent gastrointestinal tract carcinogens. The duodenum was the most sensitive tissue responding with both increased numbers of nuclear anomalies per mouse and increased incidence of animals presenting the nuclear aberrations 24 hr after a single oral dose of 0.37 mmol/kg−1 of MX. MA also induced a significant increase in duodenal nuclear anomalies, but only at the highest dose (0.46 mmol/kg−1). The proximal colon and fore‐stomach responded to MX but not MA. This is the first study demonstrating that chlorohydroxy‐furanones are capable of inducing nuclear toxicity in vivo. However, it is clear, for MX at least, that its potency in the gastrointestinal tract nuclear anomalies assay is not commensurate with its extreme bacterial mutagenicity. Since the gastrointestinal tract tissues are directly exposed to orally administered genotoxins, one possible explanation for the weak response observed in this study could be that mammalian cells can effectively detoxify chlorohydroxyfuranones.
Evaluation of the genotoxic potential of glutaraldehyde
Authors: Clair Mary Beth G. St. , Bermudez Edilberto , Gross Elizabeth A. , Butterworth Byron E. , Recio Leslie , Carrano A. V.
Published: February 2007

The cytotoxic and genotoxic effects of glutaraldehyde were studied in vitro in the human TK6 lymphoblast cell line and in primary cultures of rat hepatocytes. TK6 lymphoblasts were exposed to glutaraldehyde for 2 hr in serum‐free GSH‐free media. Cytotoxic effects were observed at concentrations as low as 10 μM with only 10% cell survival at 20 μM. Alkaline elution studies indicated that glutaraldehyde‐induced DNA‐protein crosslinking increased linearly over the concentration range from 0 to 25 μM. Glutaraldehyde‐induced mutations were assessed at the thymidine kinase locus over the same concentration range and reached a plateau at 10 μM of about six times the background mutant frequency. At equivalent levels of DNA‐protein crosslinks and cytolethality, glutaraldehyde was mutagenic at approximately a one‐seventh lower concentration than the rodent nasal carcinogen formaldehyde (Craft et al.; Mutation Research 176:147–155, 1987). Glutaraldehyde induced a marginal increase in unscheduled DNA synthesis in the in vitro hepatocyte DNA repair assay, but only at the two highest concentrations of 50 and 100 μM, indicating the induction of some DNA excision‐repair activity. These data demonstrate that glutaraldehyde exhibits DNA‐reactive genotoxic activity that may involve, at least in part, DNA‐protein crosslinking in these cell culture models. These findings suggest the need to examine the potential carcinogenic activity of glutaraldehyde in appropriate inhalation studies.
Mutagenicity of methylazoxymethanol acetate in the presence of alcohol dehydrogenase, aldehyde dehydrogenase, and rat liver microsomes in Salmonella typhimurium his G46
Authors: McMahon Timothy F. , Cunningham Michael L. , Prival M. J.
Published: February 2007

Methylazoxymethanol (MAM) is the short‐lived toxic and carcinogenic aglycone of cycasin, a natural component of the cycad plant. In the present study, the stable acetate ester of MAM, MAM acetate, was tested in combination with porcine liver esterase and Salmonella typhimurium His G46 to study the comparative mutagenicity of this compound in the presence of rat hepatic alcohol dehydrogenase (ADH), aldehyde dehydrogenase (ALDH), and rat liver microsomes. In the presence of rat liver microsomes and an NADPH‐generating system, mutagenicity of MAM acetate was not significantly altered. However, addition of rat liver 105,000g supernatant fraction and/or NAD+ significantly increased the number of his+ revertants above control. A concentration‐dependent increase in mutagenicity of MAM acetate was observed for NAD+ from 50 to 200 μM, while NADP+ caused a decrease in mutagenicity of MAM acetate in this same concentration range. Pyrazole (100–500 μM) had no significant effect on mutagenicity of MAM acetate in the presence of rat liver 105,000g supernatant, while disulfiram at 500 μM resulted in a significant decrease in mutagenicity of MAM acetate. The results of this study implicate ALDH as essential in activation of MAM acetate to a mutagenic species in this system, while the role of ADH and microsomes appears to be minimal.
Micronuclei as an index of cytogenetic damage: Past, present, and future
Authors: Heddle J. A. , Cimino M. C. , Hayashi M. , Romagna F. , Shelby M. D. , Tucker J. D. , Vanparys Ph. , MacGregor J. T.
Published: February 2007

The workshop was designed to present what is known about the production of micronuclei, what protocols are now accepted or proposed internationally, what new results have been obtained, and what new methods and protocols are likely to be forthcoming. This report is designed to convey the flavour of the workshop and to provide the essence of the new information. After the workshop an effort was made to determine what single protocol would satisfy the requirements set for the micronucleus test by as many regulatory agencies as possible. The result, reported here, includes the requirements of six regulatory authorities in Canada, the European Economic Community, the Organization for Economic Co‐operation and Development, Japan, and the United States.
Induction of prophage lambda by chlorinated organics: Detection of some single‐species/single‐site carcinogens
Authors: Demarini David M. , Brooks Harold G.
Published: February 2007

Twenty‐eight chlorinated organic compounds were evaluated for their ability to induce DNA damage using the Microscreen prophage‐induction assay in Escherichia coli. Comparison of the performance characteristics of the prophage‐induction and Salmonella assays to rodent carcinogenicity assays showed that the prophage‐induction assay had a somewhat higher specificity than did the Salmonella assay (70% vs. 50%); sensitivity, concordance, and positive and negative predictivity were similar for the two microbial assays. The Microscreen prophage‐induction assay failed to detect eight carcinogens, perhaps due to toxicity or other unknown factors; five of these eight carcinogens were detected by the Salmonella assay. However, the prophage‐induction assay did detect six carcinogens that were not detected by the Salmonella assay, and five of these were single‐species, single‐site carcinogens, mostly mouse liver carcinogens. Some of these carcinogens, such as the chloroethanes, produce free radicals, which may be the basis for their carcinogenicity and ability to induce prophage. The prophage‐induction (or other SOS) assay may be useful in identifying some genotoxic chlorinated carcinogens that induce DNA damage that does not revert the standard Salmonella tester strains.
Nitrobenzo[a]pyrene‐induced DNA amplification in SV40‐transformed chinese hamster embryo cells
Authors: Neft Robin E. , Roe Amy L. , Schol Henry M. , Fu Peter P. , Mittelstaedt Roberta A. , Casciano Daniel A.
Published: February 2007

Nitrobenzo[a]pyrenes (NBaPs) are ubiquitous environmental pollutants that produce mulations in Salmonella typhimurium and Chinese hamster ovary cells. In this study, 1‐, 3‐, and 6‐NBaP induced amplification of SV40 DNA sequences in an SV40‐transformed Chinese hamster embryo cell line which is sensitive to DNA amplification by various known carcinogens. Of the three isomers, 3‐NBaP produced the highest level of gene amplification, which was 4.8 relative to untreated controls at a dose of 5 μg/ml. Considering the relationship between gene amplification and tumorigenesis, it seems prudent to carry out a more exhaustive analysis of the carcinogenic potential of these agents.
Mutations in topA interfere with the inducible expression of DNA damage response loci in salmonella typhimurium
Authors: Smith C. Mark , Arany Zoltan , Orrego Cristian , Eisenstadt Eric
Published: February 2007

Strains of Salmonella typhimurium deficient in topoisomerase I activity (topA mutants) are UV sensitive and non‐mutable (Overbye and Margolin: J Bacteriol 146:170–178, 1981). Using lac‐operon fusions to DNA damage inducible (din) loci we investigated whether these observations could be explained by an inability of topA strains to efficiently induce DNA damage responses. Mitomycin C (MMC)‐induced expression of lac‐operon fusions to uvrB and to a second SOS locus, din‐9, was largely eliminated in topA bacteria. The inducible expression of several other din‐fusions was also diminished. This inducibility defect was mimicked by growth of din‐9 topA+ bacteria in media of high osmolarity, a condition that leads to increased DNA supercoiling. Inhibitors of DNA gyrase efficiently induced din‐9 in topA bacteria. Together, these results suggest that the topA effect on din expression may be mediated at the level of DNA supercoiling. The sensitivities of a number of din‐fusions to topA paralleled the degree to which they were repressed by excess LexA, suggesting that mutations in topA might influence LexA‐operator interactions and/or increase lexA expression.
Evidence that inhibitor(s) are formed which may interfere with the growth of revertant colonies in the ames salmonella and the E. Coli tryptophan reverse mutation assays when strictly anaerobic conditions are used
Authors: Mortelmans Kristien , Cox Mike
Published: February 2007

Spontaneous and chemically induced revertant colonies were not observed on plates when a strictly anaerobic environment and anaerobically prepared media were used to perform the Ames histidine reversion assay with each of eight different Salmonella strains. A similar effect was observed when the E. coli tryptophan reverse mutation assay was performed under strictly anaerobic conditions.

We provide evidence here that under anaerobic conditions growth inhibitor(s) are formed by the S. typhimurium and E. coli bacteria when the limited histidine and tryptophan, respectively, are depleted from the medium. The inhibitor(s) are nonspecific and inhibit the growth not only of prototrophic bacteria but also of the inhibitorproducing bacteria as measured by neutralized supernatants of growth‐limiting minimal liquid cultures. Inhibitor(s) are also formed in stationary phase cultures of Salmonella and E. coli in minimal liquid medium supplemented with excess histidine and tryptophan, respectively. These results suggest that inhibitor formation under anaerobic conditions is a physiological phenomenon which interferes with at least two reverse mutation assays. Whether or not it also interferes with the reverse mutagenesis process remains to be determined. © 1992 Wiley–Liss, Inc.
Human HPRT mutant database: Software for data entry and retrieval
Authors: Cariello Neal F. , Craft Teresa R. , Vrieling Harry , Van Zeeland Albert A. , Adams Thomas , Skopek Thomas R.
Published: February 2007

We have developed a computer database containing information on over 1,000 human hypoxanthine guanine phosphoribosyl transferase (HPRT) mutants. Both published and unpublished data are present. The database itself is maintained in a dBASE format (.DBF) and we provide a set of programs to examine and extract information from the database. A program to input information into the database is also supplied. The database and programs are available directly from us or via remote FTP (file transfer protocol) using BITNET/INTERNET. All programs require an IBM‐compatible computer, the MS‐DOS operating system (version 3.3 or greater), and a hard disk with about 5 megabytes of free disk space.

The purpose of the database is 1) to allow investigators to contribute their HPRT mutants directly to the database in a standardized fashion, and 2) to allow access to the entire database with a set of programs that allows manipulation and extraction of data. For example, using our programs it is possible to i) order the database by base pair position, ii) examine only information regarding mutagenesis by a particular agent, iii) search for a particular author, iv) create a report which contains selected portions of the database, the report can be printed or saved as a file.

The database will be updated every several months and distributed. © 1992 Wiley‐Liss, Inc.
Evaluation of the mutagenicity of an n‐nitroso contaminant of the sunscreen padimate O: N‐nitroso‐N‐methyl‐p‐aminobenzoic acid, 2‐ethylhexyl ester (NPABAO)
Authors: Dunkel Virginia C. , San Richard H. C. , Harbell John W. , Seifried Harold E. , Cameron Thomas P.
Published: February 2007

The nitrosamine contaminant, N‐nitroso‐N‐methyl‐p‐aminobenzoic acid, 2‐ethylhexyl ester (NPABAO), of the major sunscreen ingredient Padimate O (4‐N, N′‐dimethylamino‐benzoic acid, 2‐ethylhexyl ester) was synthesized and tested for mutagenicity in the Salmonella typhimurium and mouse lymphoma L5178Y TK+/‐assays. In contrast to the previously reported positive responses in S. typhimurium tester strains TA100 and TA1535 [Loeppky et al., 1991], there were no increases in the number of revertants with strains TA98, TA100, TA1535, and TA1538 in either the Salmonella plate incorporation [Ames et al., 1975] or preincubation [Yahagi et al., 1977] assays. Additional testing with Salmonella, following the modified preincubation procedure [Rogan, 1990] that gave the initial positive response, was also negative. Data from the mouse lymphoma assays were also uniformly negative.

During synthesis of NPABAO, small amounts of 4‐N, N'‐dimethylamino‐3‐nitrobenzoic acid, 2‐ethylhexyl ester (DMANBAO) can be formed. To determine whether the reported positive mutagenicity response of NPABAO could be the result of trace amounts of DMANBAO in the NPABAO, that compound was also synthesized and tested for mutagenicity with Salmonella. Positive responses were obtained with tester strains TA98 and TA 1538 but not with TA100 and TA1535, indicating that DMANBAO was not responsible for the increase in revertants originally reported. © 1992 Wiley‐Liss, Inc.
Mutagenicity and antimutagenicity of hispidulin and hortensin, the flavonoids from Millingtonia hortensis L.
Authors: Chulasiri Malyn , Bunyapraphatsara Nuntawan , Moongkarndi Primchanien
Published: February 2007

Studies of the mutagenicity and antimutagenicity of hispidulin and hortensin, the flavonoids from Millingtonia hortensis L. (Bignoniaceae), were performed using the liquid preincubation method of the Salmonella/microsome test. At the highest dose tested, 100 μg/plate, both compounds showed no mutagenicity and no cytotoxicity toward S. typhimurium strains TA98 and TA100 either in the presence or absence of S9 mix. However, these substances were antimutagens toward 2–aminoanthracene, aflatoxin Bl (in TA98), and dimethylnitrosamine (in TA100); but neither substance inhibited the direct mutagenic activity of 2‐(2‐furyl)‐3‐(5‐nitro‐2‐furyl) acrylamide nor that of sodium azide in strains TA98 and TA100, respectively. © 1992 Wiley‐Liss, Inc.
Japanese guidelines for mutagenicity testing
Authors: Sofuni Toshio
Published: February 2007

Several Japanese agencies are required to perform mutagenicity tests according to regulatory guidelines. Although each agency's guidelines address a specific purpose, the experimental principles behind them are similar, and general methodological recommendations have been issued by the Ministry of Agriculture, Forestry, and Fisheries [1985]; Ministry of Health and Welfare [1990]; Ministry of Labor [1991]; and Ministry of Health and Welfare [1992]. Four major guidelines for mutagenicity testing in Japan and some amendments are briefly introduced. In addition, several procedures in Japanese guidelines that differ from those of other countries or organizations are discussed. © 1993 Wiley‐Liss, Inc. © 1993 Wiley‐Liss, Inc.
In vitro micronucleus bioassay of human peripheral lymphocytes for adriamycin in the presence of cyclophosphamide and urines of patients administered anticancer drugs
Authors: Boucher R. , Livingston G. K. , Hee S. S. Que
Published: February 2007

The aim of this study was to develop an in vitro human peripheral lymphocyte micronucleus bioassay involving phytohemagglutinin stimulant for urines containing adriamycin (ADR) and cyclophosphamide (CP). In vitro studies with defined concentrations of ADR, CP, and fresh urine showed that mitotic indices and micronuclei counts/1,000 cells had to be log (X + 1) transformed to be able to use parametric statistics and that a specific micronucleus assay for ADR in the presence of CP and urine for 5–15 ng ADR/mL had been developed. Whereas CP alone could be detected between 196–522 μg/mL, this effect was abolished in the presence of 15 ng ADR/mL. Interdonor variabilities relative to ADR sensitivity and CP linear dynamic range were marked, but intradonor variability was small. The MN bioassay tolerated < 10% urine. Results for urines from nine patients receiving antineoplastic drugs (CP, all; ADR, 3; 5‐fluorouracil, 3; methotrexate, 3; vincristine, 4; procarbazine, 1; and megestrol acetate, 1) showed that only 1/3 patients given ADR were detected, and two others not given ADR were positive. All frozen urines from the 12 control subjects and the nine patients exhibited depressed mitotic index, with, however, no control patient urines inducing increased micronuclei. Two patients had urines of undefined genotoxic potential since undepressed mitotic indices were not attainable by dilution. The effects of combination chemotherapy in addition to freezing and storage influences were complex. More research is required to be able to interpret the results. ©1993 Wiley‐Liss, Inc.
DNA damage, photorepair, and survival in fish and human cells exposed to UV radiation
Authors: Ahmed Farid E. , Setlow Richard B. , Grist Eleanor , Setlow Neva
Published: February 2007

The effect of various wavelengths of UVB radiation on the induction of cyclobutane pyrimidine dimers in fish cells and human fibroblasts and the repair of these lesions were studied using an UV‐endonuclease to measure dimers (endonuclease sensitive sites) by sedimentation of radioactive DNA, by gel electrophoresis of unlabeled DNA, and by cell survival. The data show that fish cells have an efficient photoreactivation system at wavelength > 304 nm that reverses cytotoxicity and dimer formation after exposure to filtered sunlamp irradiation of a shorter wave‐length (λ > 290 nm). Shorter wavelengths in UVB (<304 nm) are more effective in photoreversal than longer ones (<320 nm). As a consequence, 50–85% of dimers induced by these wavelengths in fish are photoreactivated while they are being formed. A major cytotoxicological lesion is the cyclobutane pyrimidine dimers. Cultured human fibroblasts do not possess such a repair system. These results indicate that sun‐lamp irradiation has wavelengths that both damage and repair DNA.
Dose‐dependent genotoxic effects of styrene on human blood lymphocytes and the relationship to its oxidative and metabolic effects
Authors: Chakraborti Saroj , Duhr Marie‐Ange , Senécal‐Quevillon Micheline , Richer Claude‐Lise
Published: February 2007

Although the genotoxic potential of styrene is known, very limited information is available regarding its dose‐dependent genotoxic response to human blood lymphocytes and how such response correlates with different metabolic events in whole blood lymphocytes. The present study was therefore carried out to study such a relationship using in vitro human blood lymphocytes from healthy volunteers. To study genotoxic response to styrene, sister chromatid exchanges (SCEs), cell cycle, and cell survival were analyzed. Lymphocytes were cultured for 72 hr in the presence of different concentrations of styrene (0–1,000 μM). Twenty‐four hr before harvest, BrdU (5 μg/ml) was added to assess the increase in SCEs and cell cycle delay. Both the SCE frequency and the cell cycle length were increased linearly with increasing concentrations of styrene up to 200 μM, without addition of any exogenous metabolizing system. Above 200 μM, no further increase in genotoxic response occured. The range of concentrations (10–200 μM) at which increase of cell cycle length due to styrene was observed did not impair the viability of the cells, suggesting that such cell cycle delay is a genotoxic‐related event and not caused by cytotoxicity. In vitro metabolic transformation of styrene in whole‐blood lymphocyte cultures without the presence of any exogenous metabolic activation system showed the formation of a reactive intermediate, styrene 7,8‐oxide, to be capacity‐limited, as verified from a nonlinear increase in the formation of styrene glycol. The value of such metabolic parameter reached a plateau above 200 μM styrene. The same phenomenon of saturation has also been observed with regard to other metabolic effects due to styrene in whole blood lymphocytes in culture, such as dose‐dependent increase in lipid peroxidation and depletion of blood lymphocyte glutathione. Based on the relationship between the formation of different metabolic events and the genotoxicity of styrene, it may be possible that the genotoxic properties of styrene in human blood lymphocytes may be mediated initially not only by the formation of the presumably reactive styrene 7,8‐oxide, but also by that of a reactive oxygen species as well. However, the present data are not sufficient enough to definitely identify the role of reactive oxygen species in such toxicity and therefore it warrants further study. © 1993 Wiley‐Liss, Inc.
p53 mutations in human bladder cancer
Authors: Kusser Wolfgang C. , Miao Xili , Glickman Barry W. , Friedland Joan M. , Rothman Nathaniel , Hemstreet George P. , Mellot John , Swan David C. , Schulte Paul A. , Hayes Richard B.
Published: February 2007

Mutations in the tumor suppressor gene p53 play an important role in carcinogensis and tumor progression. To assess the status of p53 from genomic DNA from bladder cancer samples a two stage polymerase chain reaction was employed. The technique provided material for subsequent detection of mutations by Single Strand Conformation Polymorphism (SSCP) analysis followed by DNA sequence analysis. SSCP analysis of exons 5 to 9 of p53 was performed using fragments from PCR end‐labeled with 32P followed by autoradiography using an electrophoresis system with temperature control. This SSCP method improved resolution of mutations in exons 5, 7, and 8 and the sharpness of bands in exons 6 and 9. Bands with altered migration patterns were excised from the dried SSCP gels, reamplified by PCR, and sequenced. Mutations in conserved exons 5, 6, 7, 8, and 9 of the p53 gene were analyzed from bladder tumor biopsies. Our results are consistent with the literature in that mutations in p53 are predominantly found in high grade bladder cancer (Odds Ratio = 4.05, Fisher Exact P = 0.104); however, the results were not statistically significant due to small numbers. Eight of 35 (23%) tumor samples examined showed mutations in p53 (including two double mutations). Six of 13 (46%) grade III and IV tumors had p53 mutations vs. 2 of 17 (12%) grade I and II tumors. Normal individuals carried no p53 mutations. We found no correlation between pack years of smoking and mutation in p53. The spectrum of mutations confirmed a high proportion of G:C C:G transversions as well as the occurrence of double mutations. © 1994 Wiley‐Liss, Inc.
Statistical tests of significance in transgenic mutation assays: Considerations on the experimental unit
Authors: Carr G. J. , Gorelick N. J.
Published: February 2007

When significant animal‐to‐animal variability is present in binary response data, the usual statistical tests applied to such data do not always operate correctly. In transgenic mouse mutation data, some evidence of significant animal‐to‐animal variability already exists, suggesting that conventional statistical methods may not be appropriate. Here, we describe an alternative statistical method that treats the animal as the experimental (or statistically independent) unit, and contrast results of its application with those from methods that take the transgene as the experimental unit. Using data from two publications that report experimental results for individual animals, the transgene‐based and animal‐based analyses can yield very different interpretations of the experimental data. The performance of animal‐based statistical methods should be improved by conducting future experiments with enough animals to adequately address animal‐to‐animal variability. © 1994 Wiley‐Liss, Inc.
Hprt mutant frequency and GSTM1 genotype in non‐smoking healthy individuals
Authors: Hou Sai‐Mei , Fält Susann , Steen Ann‐Marie
Published: February 2007

The T‐cell cloning assay which combines mito‐gen‐ and growth factor‐dependent expansion of lymphocyte clones with thioguanine selection of hypoxanthine‐guanine phosphoribosyl trans‐ferase (hprt)‐negative cells has been extensively used for studying human somatic gene mutation in vivo. However, large interindividual variations in the hprt mutant frequency (MF), much of which is not explained by donor attributes such as age and smoking habit, and interlaboratory variations in the experimental methodology, including cloning efficiency (CE), call for further developments of the cloning protocol and additional population studies. Using an improved T‐cell cloning method, we have studied in vivo hprt MF of 76 non‐smoking healthy males aged 23–77 years. The addition of 5% human serum to the growth medium was found to produce a consistently high CE of 61% in average. The MF, ranging from 1.4 to 22.6 × 10−6 with a mean of 8.6 × 10−6, increased significantly (P < 0.0001) with age, by 2% per year. A significant (P = 0.002) inverse relationship between MF and CE was observed. Using a PCR‐based technique for GSTM1‐genotyping, we also studied the relationship between MF and GSTM1 polymorphism. The 38 (50%) GSTM1‐negative individuals showed a 20% higher mean MF than the 38 (50%) GSTM1‐positive individuals. The difference was however not significant, neither before (P = 0.1) nor after (P = 0.5) correction for CE and the significantly (P = 0.04) higher mean age in the GSTM1‐negative group. This study shows that age contributes more than GSTM1 polymorphism to the large interindividual variation in the hprt MF of non‐smokers. The relationship between GSTM1 polymorphism and hprt MF in smokers remains to be investigated. © 1995 Wiley‐Liss, Inc.
Effects of vinblastine and colchicine on male rat meiosis in vivo: Disturbances in spindle dynamics causing micronuclei and metaphase arrest
Authors: Kallio Marko , Sjöblom Tiina , Lähdetie Jaana
Published: February 2007

We have studied the effects of vinblastine sulfate (VBL) and colchicine (COL) on male rat in vivo and in vitro meiosis. A novel methodology based on isolating a segment of seminiferous tubules containing meiotically dividing spermatocytes was applied. During meiotic divisions at stage XIV of rat spermatogenesis, both chemicals induced only low frequencies of micronu‐clei (MN), 0.8–3.2 MN/1,000 spermatids. Fluorescence in situ hybridization experiments in mice with the mouse centromere‐specific y‐sat‐ellite DNA probe showed that 50.7% of VBL‐induced MN and 56.6% of COL‐induced MN were centromere positive, indicating that the MN induced by both chemicals contained detached chromosomes. The inhibition of cell proliferation was determined by counting the number of cells arrested at metaphase during the first meiotic (MI) or the second meiotic (MII) division. VBL was found to be a potent inducer of cell death while COL was not. The direct effects of VBL and COL on the meiotic spindles were evaluated using immunohistochemistry with anti‐a‐tubulin and confocal microscopy. In the control animals a significant difference was observed between the mean length of metaphase spindles of MI and MII Both were dramatically decreased 6 hr after treatment with 2.0 mg/kg of VBL and 0.8 mg/kg of COL, respectively. At 18 hr after COL injection the spindles had about the same length as in the controls. However, the VBL‐induced shortening was even more evident at 18 hr for both Ml and Mll. The possible reasons for observed differences between the two chemicals and between meiosis and mitosis are discussed. © 1995 Wiley‐Liss, Inc.
Aneugen‐induced micronuclei (MN) in human lymphocytes may be discerned using image analysis techniques when cell‐cycle stage is taken into account
Authors: Van Hummelen P. , Nüsse M. , Castelain P H. , Kirsch‐Volders M.
Published: February 2007

We show that for the in vitro cytochalasin‐B human lymphocyte micronucleus (MN) test, the quantification of the DNA content of MN and the difference in DNA content between the two macronuclei in the binucleate cells without MN, as measured by image analysis, gives a first estimation of the aneugenic potential of a test compound. Cultures of isolated human lymphocytes were exposed either to γ‐rays as a clastogen or to carbendazim (MBC) as an an‐eugen. The lymphocytes were stained with Feulgen stain and the MN were analyzed for DNA content with a Magiscan 2A image analyzer. The mean DNA content of MN induced by MBC were statistically higher than γ‐irradiation‐induced MN. It was demonstrated that in culture the lymphocytes, as well as the MN, are in different stages of the cell cycle, but this will not affect the discriminating power of the MN DNA content when only G1 cells are considered, or when DNA content of the MN is expressed relative to the total genome. The identification of Gl and G2 cell populations from image analysis data was performed by extrapolation of DNA content data from Gl‐ and G2‐sorted lymphocytes with a FacStar plus flow sorter. It was demonstrated that in MBC‐treated cells the DNA rearrangement between the macronuclei in binucle‐ates without MN was on the average higher than in γ‐irradiated and untreated cells, which points to aneugenic effects of MBC without the formation of MN. In contrast to DNA content measurements, the area of the MN is not a reliable measure for discriminating clastogens from aneugens. © 1995 Wiley‐Liss, Inc.
Micronuclei in mice treated with monocrotaline with and without phenobarbital pretreatment
Authors: Higgins Michael J. , Ficsor Gyula , Aaron C. S. , Petry Thomas W. , Yu Roger L. , Friedman Stephen B.
Published: February 2007

Monocrotaline is a very potent toxin, producing significant effects of pneumotoxicity, hepatotoxicity, and teratogenicity, as well as carcinogenicity. In addition, the compound has been clearly shown to be muta‐genic after metabolic activation. The goal of the experiments reported here was to confirm the reported clastogenesis induced by this agent in vivo and to evaluate the impact of modulation of metabolic activity by phenobarbital, a potent P‐450 inducer (both Phase I and Phase II enzymes). The method used in addressing this problem relied on a new technique for monitoring clastogenesis in vivo, i.e., the acridine orange micronucleus assay method originally exploited by Hayashi et al. [1990].

The result of our experiments confirmed monocro‐taline to be an effective clastogen in vivo, using the acridine orange method of assessment. The peak in induction of micronuclei occurred on the second day following intraperitoneal administration of the drug. Administration of phenobarbital prior to monocrotaline did appear to modulate the micronucleus induction. At 30 mg/kg bw monocrotaline, the pretreatment with phenobarbital appears to increase the intensity of monocrotaline clastogenesis, while the effect at higher doses (60 and 125 mg/kg bw) is a reduction in potency, presumably reflecting increased importance of Phase II metabolism for monocrotaline at these doses. Thus the study reported here confirms the potent in vivo clastogenesis of monocrotaline, and provides evidence for a dose‐related shift in mechanism for the phenomenon. © 1995 Wiley‐Liss, Inc.