bluuebunny/crossref_metadata_2025 huggingface dataset:
A program allocation method for real‐time processing based on data‐driven processors
Authors: Kurebayashi Ryosuke , Nishikawa Hiroaki
Published: February 2007

In this paper the authors propose a program allocation method for the purpose of achieving real‐time processing using a chip multiprocessor‐type data‐driven processor. The data‐driven processor can perform parallel processing of executable processes without interference as long as the pipeline is not overloaded. The turnaround time for the individual processes being subjected to multiprocessing is independent of other processes being executed at the same time, and is maintained as is for the execution time when a single process is executed. Therefore, real time for a program can be estimated, and if the program can be allocated to a process such that overload does not occur, then real‐time processing can be achieved without scheduling during execution. In this paper the authors first formalize a program allocation method in a data‐driven processor. They then propose a combined method using genetic algorithms and a heuristic algorithm that uses lists as a program allocation method that is better at satisfying the time constraints and offers greater scalability for large‐scale program and multiprocessor systems to be subjected to allocation. Finally, the authors use experiments in which a communications protocol process is allocated to verify the effectiveness of their program allocation method. © 2007 Wiley Periodicals, Inc. Electron Comm Jpn Pt 3, 90(6): 48– 60, 2007; Published online in Wiley InterScience (www.interscience. wiley.com). DOI 10.1002/ecjc.20324
Quantification of polyamines in human erythrocytes using a new near‐infrared cyanine 1‐(ϵ‐succinimidyl‐hexanoate)‐ 1′‐methyl‐3,3,3′,3′‐tetramethyl‐ indocarbocyanine‐5,5′‐disulfonate potassium with CE‐LIF detection
Authors: Fu Ni‐Na , Zhang Hua‐Shan , Ma Ming , Wang Hong
Published: February 2007

A novel near‐infrared (NIR) cyanine 1‐(ϵ‐succinimidyl‐hexanoate)‐1′‐methyl‐3,3,3′,3′‐tetramethyl‐indocarbocyanine‐5,5′‐disulfonate potassium (MeCy5‐OSu) has been developed in our laboratory. Simultaneous determination of MeCy5‐OSu‐derivatized polyamines spermine (Spm), spermidine (Spd), cadaverine (Cad), and putrescine (Put) based on the separation by CE combined with diode LIF detection has been accomplished. The highest derivatization efficiency was achieved in 0.2 mol/L borate buffer (pH 8.8) for 20 min at 25°C. Polyamine derivatives were separated within 14 min in the phosphate running buffer (pH 3) containing 50 mmol/L phosphoric acid, 40 mmol/L SDS, and 35% methanol v/v. Linearity of response was obtained in the range of 10–200 nmol/L. The detection limits (S/N = 3) for Spm, Spd, Cad, and Put were 0.8, 1, 3, and 2 nmol/L, respectively. The proposed method has been successfully applied to the analysis of polyamines in erythrocytes of two healthy persons and one cancer patient. Average recoveries for erythrocyte samples were 93.6–106% and coefficients of variation ranged from 1.8 to 5.4%. The analysis of polyamines in erythrocytes can be used for studying the relationship between their changes and the carcinogenesis process involved in erythrocytes.
A novel view of gel‐shifts: Analysis of RNA–protein complexes using a two‐color fluorescence dye procedure
Authors: Shcherbakov Dmitry , Piendl Wolfgang
Published: February 2007

The electrophoretic mobility shift assay (EMSA) is a common technique to identify and analyze RNA–protein interactions, using the altered electrophoretic mobility of RNA and/or protein upon forming an RNA–protein complex. Traditional techniques of visualization of the EMSA results include either prelabeling of RNA before complex formation or specific RNA‐ or protein‐staining after electrophoresis. Recently, two‐color fluorescent staining (TCFS) methods were developed, in which the nucleic acid is stained first and scanned; subsequently, the protein is stained and scanned. In the current study, we developed a TCFS system, in which RNA and protein are stained with SYBR Green I and with SYPRO Red, respectively. The gel is subsequently scanned in two channels in a laser scanner to detect both simultaneously. Furthermore, we show that tetramethylrhodamine (TAMRA)‐labeled proteins can subsequently be monitored in multicomponent RNA–protein complexes. This novel two‐color fluorescence staining is simple, sensitive, and significantly faster than other comparable procedures and allows the independent quantitative determination of both free or complexed nucleic acids and proteins. The interactions between 23S rRNA and ribosomal protein L11 and the ribosomal protein complex L10/L124 were used to demonstrate the advantages of this method.
A novel method of protein extraction from perennial Bupleurum root for 2‐DE
Authors: Xie Hui , Pan Shengli , Liu Shufen , Ye Kan , Huo Keke
Published: February 2007

The perennial Bupleurum root is thick and woody and contains high levels of interfering compounds. Common protein extraction methods have proved refractory towards the isolation of proteins suitable for 2‐DE, due to the presence of interfering compounds. A novel method for extracting proteins suitable for 2‐DE was established to overcome these problems. The main characteristic of this protocol is the partitioning of the proteins into the aqueous (fraction A‐2), chloroform and isoamyl alcohol phases (A‐3), and the interphase (A‐1). The proteins are then extracted from each of these phases. From A‐1, 85% (extracted protein against total proteins) proteins could be extracted and purified. For fraction A‐2, a novel phenol extraction step is employed for the extraction of proteins. Based on the well‐resolved 2‐DE patterns, our protein preparation is free of interfering compounds. Using these methods (A‐1, A‐2, and A‐3‐3), a total of 3662 (1526 + 1128 + 1008) spots could be separated, and a protein yield of about 1.41 mg per 1.0 g fresh root material was obtained. To our knowledge, this is the first time that a protocol for protein extraction from perennial Bupleurum root has been reported that gives reproducible results. The protocol is expected to be applicable to other recalcitrant plant tissues as well.
A recombinagenic effect of strychnine in Salmonella typhimurium
Authors: Hoffmann George R. , Sprague Kathleen M. , Wrobel John A. , Wroblewski Diane H.
Published: February 2007

The aroC321 allele in Salmonella typhimurium permits a positive selection for genetic duplications. Bacteria that contain a large genetic duplication are detected as tryptophan prototrophs in aroC321 strains and occur at a spontaneous frequency greater than 1/104 cells plated on the selection medium. Duplications originate by a recombinational mechanism, and the induction of duplications by chemicals or radiation may therefore be considered to be a recombinagenic effect. We have found that strychnine is a potent recombinagen in this system; it causes a dose‐dependent increase in the frequency of genetic duplications, and very high frequencies of duplications are recovered at high doses. In contrast, brucine, the 2,3‐dimethoxy derivative of strychnine, caused no increase in duplication frequencies under the identical conditions.
Cd2+ tolerance in Escherichia coli and Salmonella typhimurium
Authors: Hartman Philip E. , Kuo Dick C.
Published: February 2007

Relative tolerance of Escherichia coli strains to Cd2+ is induced by prior growth in medium containing low levels of either Cd2+ or Hg2+, and maximal induction appears to be dependent upon recA+ function. Biosynthesis of glutathione is not required for induction or for expression of induced resistance. Salmonella typhimurium strains are relatively resistant to Cd2+, and this resistance is essentially constitutive.
Phototoxic effects of fluoranthene, a polycyclic aromatic hydrocarbon, on bacterial species
Authors: Tuveson R. W. , Kagan J. , Shaw M. A. , Moresco G. M. , v. Behne E. M. , Pu H. , Bazin M. , Santus R.
Published: February 2007

Fluoranthene, a non‐carcinogenic polycyclic aromatic hydrocarbon, inactivatesEscherichia colicells in the presence of near‐ultraviolet light (NUV; 300–400 nm).E colicells carrying defects in theuvrA6orkatFgenes are sensitized to inactivation by the simultaneous treatment with fluoranthene and NUV, suggesting that DNA is a target and that hydrogen peroxide is generated.Haemophilus influenzaetransforming DNA can be inactivated by the simultaneous treatment with fluoranthene and NUV confirming DNA as a target. Using the photooxidation of imidazole and histidine as probes, fluoranthene was found to generate singlet oxygen in organic and aqueous media. In water, it participated in electron transfer reactions, reducing nitro blue tetrazolium as well as ferricytochrome C. This reduction took place both in the presence of air, where superoxide anion was formed, and under argon. Simultaneous treatment with fluoranthene and NUV was incapable of inducing histidine‐independent mutations. Simultaneous treatment with fluoranthene and NUV was incapable of inducing theuvrAgene product as evidenced by the absence of the induction of beta‐galactosidase in anE colioperon fusion strain [uvrA215::Mud(Ap,lac)].
Specific reduction of N,N‐dimethylnitrosamine mutagenicity in Drosophila melanogaster by dimethyl sulfoxide
Authors: Brodberg R. K. , Mitchell M. J. , Smith S. L. , Woodruff R. C.
Published: February 2007

Dimethyl sulfoxide (DMSO) used as a solvent has been observed to complicate mutagenicity screens by interacting with tested chemicals to yield false positives or negatives. We have used DMSO as a solvent in the Drosophila melanogaster recessive sex‐linked lethal mutation assay and find that it reduces, but does not abolish, the detectable mutagenicity of N,N‐dimethylnitrosamine (DMN). Its use as a solvent with procarbazine, another promutagen, shows no effect on mutagenicity in Drosophila. DMSO does not exhibit a general inhibitory action on microsome activity when ecdysone 20‐monooxygenase activity is used as a measure of cytochrome P‐450 activity. We were unable to detect the low DMN demethylase activity in the strain used. Hence, the inhibitory effect of DMSO in Drosophila at both the physiological and biological level appears to be limited and not general in action. Because DMN and DMSO are similar in structure, it is possible that DMSO is interacting with a DMN demethylase in Drosophila. This might lead to a reduction in the conversion of DMN to a mutagen. Consequently, from the results of this study and others DMSO should be used cautiously as a solvent in Drosophila mutagen screening.
Genotoxicity of acrylic acid, methyl acrylate, ethyl acrylate, methyl methacrylate, and ethyl methacrylate in l5178y mouse lymphoma cells
Authors: Moore Martha M. , Amtower Amanda , Doerr Carolyn L. , Brock Karen H. , Dearfield Kerry L.
Published: February 2007

A series of monomeric acrylate/methacrylate esters (methyl acrylate, ethyl acrylate, methyl methacrylate, and ethyl methacrylate) as well as acrylic acid were examined for genotoxic activity in L5178Y mouse lymphoma cells without exogenous activation. All five compounds induced concentration‐dependent increases in mutant frequency. Small‐colony, trifluorothymidine‐resistant mutants were primarily induced, which suggests that these compounds may act via a clastogenic mechanism. This prediction was confirmed by the finding that all five compounds produced gross chromosome aberrations in mouse lymphoma cells. The two acrylates were much more potent in their response than acrylic acid. Methyl acrylate (22 μg/ml, survival = 18%) induced 385 mutants/106 survivors (total mutant frequency less the spontaneous mutant frequency) and 45 chromosome aberrations/100 cells analyzed (total aberrations less the spontaneous background). Ethyl acrylate (37.5 μg/ml, survival = 15%) induced 683 mutants/106 survivors.
Flavone mutagenicity in salmonella typhimurium: Dependence on the PKM101 plasmid and excision‐repair deficiency
Authors: Macgregor J. T. , Wilson R. E.
Published: February 2007

Flavones mutagenic in Salmonella typhimurium fall into two distinct classes, characterized by different structural and metabolic activation requirements and by different strain responses. The mutagenic potencies of a prototype agent of each class, quercetin (3,3′,4′,5,7‐hydroxyflavone) and norwogonin (5,7,8‐hydroxyflavone), were determined in tester strains differing in excision‐repair capability and in the presence or absence of plasmid pKM101. Two series of strains were used, one with the hisD3052 frameshift mutation and one with the hisG46 missense mutation. With both agents and for both series of strains, the mutagenic response was markedly dependent on the absence of excision repair and the presence of the pKM101 plasmid.
Mutagenicity of nitro compounds in Salmonella typhimurium in the presence of flavin mononucleotide in a preincubation assay
Authors: Dellarco Vicki L. , Prival Michael J.
Published: February 2007

A series of nitro compounds (18 aromatic and one aliphatic) was evaluated using a modification of the standard Salmonella typhimurium mutagenicity assay. A preincubation protocol was used with flavin mononucleotide (FMN) incorporated into the assay mixture to facilitate nitro reduction. Several aromatic nitro compounds (m‐nitroaniline, p‐nitroaniline, 2, 6‐dinitrotoluene, 2,4‐dinitrotoluene,2,3‐dinitrotoluene, 1,8‐dinitro‐naphthalene), which were negative or only weakly mutagenic when tested in the standard plate incorporation assay, showed FMN‐dependent mutagenic responses with this procedure. For some nitro compounds, the addition of FMN was not needed for the detection of mutagenicity in the modified protocol. Not all nitro compounds were positive using the preincubation procedure with FMN. The lack of mutagenicity, however, does not appear to be the result of the inability of the modified method to reduce nitro compounds, since it was found that reduction does occur under the assay conditions for the two nonmutagens evaluated for nitro reduction (nitrobenzene and p‐nitrophenol). It is suggested that the modified protocol may be useful for evaluating the mutagenicity of many nitro compounds.
Micronuclei in binucleated lymphocytes of mice following exposure to gamma radiation
Authors: Erexson Gregory L. , Kligerman Andrew D. , Halperin Edward C. , Honore Gerard M. , Allen James W.
Published: February 2007

Experiments were designed to investigate the induction of micronuclei (MN) in mouse peripheral blood lymphocytes (PBLs) after in vitro or in vivo exposure to 60Co gamma radiation. For the invitro experiments, 4 ml of blood from male C57BL/6J mice were either irradiated in 6 ml Falcon culture tubes as whole blood or isolated to obtain mononuclear leukocytes (MNLs) that were pelleted by centrifugation and then irradiated in RPMI 1640. For the in vivo analysis, mice received whole body irradiation, blood was obtained by cardiac puncture, and the MNLs were isolated for each mouse. Exposures were at a rate of 0.82 to 0.90 Gy/min to yield doses of 0.5, 1, 2, 3, or 4 Gy. MNLs were cultured using cytochalasin B for MN analysis in binucleated PBLs. There was a significant dose‐dependent increase in MN observed at all doses. Dose‐response curves for the in vivo and in vitro whole blood experiment were not significantly different. However, for isolated pelleted MNLs irradiated in vitro, the MN frequency at 4 Gy was less than one‐half that seen in the in vivo experiment. The large difference in MN response is thought to be due to the radioprotective effect of hypoxia.
Conditions affecting the mutagenicity of trichloroethylene in Salmonella
Authors: McGregor D. B. , Reynolds D. M. , Zeiger E.
Published: February 2007

Trichloroethylene (TCE) is a high production volume chemical frequently stabilized with oxiranes. These oxiranes may be responsible for the mutagenic activity of TCE in Salmonella, which has been occasionally, but not consistently, reported. High purity and oxirane‐stabilized TCE samples were tested for their mutagenic potential in Salmonella typhimurium strains TA 1535, TA 98, and TA 100. Stabilized TCE was tested using a preincubation protocol up to a dose level of 10,000 μ per plate, but no mutagenic response was observed in either the presence or absence of a supplementary metabolic activation system (S9 mix) derived from Aroclor 1254‐induced male rat liver. TCE without oxirane stabilizers also was nonmutagenic when tested in a vapor delivery system at nominal concentrations of up to 20% and using S9 mix derived from either rat or hamster. TCE containing 0.5–0.6% 1, 2‐epoxybutane did induce mutagenic responses from strains TA 1535 and TA 100 in the presence and absence of S9 mix. The lowest effective dose was about 0.63% in TA 1535 in the absence of S9 mix. Vapor‐phase tests with 1, 2‐epoxybutane showed that an atmospheric concentration of 0.009% could induce 12‐fold and 3‐fold increases, respectively, in strains TA 1535 and TA 100. These increases would account for the mutagenic activity of the stabilized TCE sample. Epichlorohydrin (another commonly used stabilizer) induced similar increases in mutant numbers at an atmospheric concentration of 0.0009%. The absence of a significant response caused by unstabilized TCE in the presence of S9 mix is probably due to a lack of assay sensitivity, since chloral, a metabolite of TCE, is a mutagen in TA 100 [Haworth et al.: Environ Mutagen [Supplement 1] 5:3–142, 1983].
The effects of acrylamide on mouse germ‐line and somatic cell chromosomes
Authors: Backer Lorraine C. , Dearfield Kerry L. , Erexson Gregory L. , Campbell James A. , Westbrook‐Collins Barbara , Allen James W.
Published: February 2007

The industrial chemical acrylamide is suspected to induce potentially heritable genetic damage. While several studies in rodents have indicated that this substance can damage spermiogenic cells, resulting in dominant lethals and heritable translocations, cytogenetic assessments of premeiotic and meiotic cells after exposure have produced equivocal results. In the present study, various cytogenetic endpoints in both somatic and germ‐line cells from acrylamide‐treated mice were evaluated. Sister chromatid exchanges and micronuclei, but not chromosome aberrations, were induced in spleen cells; synaptonemal complex irregularities (asynapsis), but not chromosome aberrations, were induced in germ cells.
Mutagenicity of airborne particles from a nonindustrial town in Italy
Authors: Barale Roberto , Zucconi Donatella , Giorgelli Francesco , Carducci Anna Laura , Tonelli Margherita , Loprieno Nicola
Published: February 2007

The mutagenic activity of airborne particulate matter collected in Pisa, a small nonindustrial town located in Italy, has been monitored over 1 year using the Ames Salmonella Test. Airborne particulate was collected on fibreglass filters using a Hi‐Vol sampler and extracted by sonication and Soxhlet acetone extraction in sequence. TA 98 and TA 100 salmonella strains gave positive results with the great majority of samples. The mutagenicity trend fits with a harmonic regression with a peak during December/January and inversely correlates with the temperature. No correlations were observed with other meteorological conditions such as wind, cloud, rainfall, atmospheric pressure, and humidity. The ratio between mutagenicity/μg of particulate matter with S9 and that without S9 remains more or less constant regardless of seasonal fluctuations, suggesting that during cold months quantitative increases of mutagens onto particulate matter have probably occurred. The comparison of air mutagenicity in different sites suggests that motor vehicle exhaust fumes are the major source of air pollution. Finally, because of high‐traffic volume, air mutagenicity at street level is comparable to that observed in several metropolitan areas all over the world.
Absence of mutagenic interaction between microwaves and mitomycin C in mammalian cells
Authors: Meltz Martin L. , Eagan Phyllis , Erwin David N.
Published: February 2007

Evidence in the literature from in vitro and in vivo studies as to whether or not radiofrequency radiation (RFR) in the microwave range is mutagenic is predominantly negative, with some positive reports. No evidence is available as to whether RFR will alter the mutagenic activity of genotoxic chemicals during a simultaneous exposure, a likely real‐life situation. Two hypotheses have been proposed: a) that RFR by itself can cause mutations in a mammalian cell in vitro assay system; and b) that a simultaneous exposure to RFR during a chemical treatment of the cells with a known genotoxic agent, mitomycin C (MMC), will alter the extent of mutagenesis induced by the treatment of the cells by the chemical alone. These studies were performed using the forward mutation assay at the thymidine kinase locus in L5178Y mouse leukemic cells. The pulsed wave RFR was broadcast from an antenna horn at a frequency of 2.45 GHz. The power density was 48.8 mW/cm2 and the measured specific absorption rate (SAR) in this system was 30 W/kg (600 W forward power), which is well above current safety guidelines. The conclusions from five different experiments, employing three different concentrations of MMC, were that a) RFR exposure alone, at moderate power levels which resulted in a temperature increase in the cell culture medium of less than 3°C, is not mutagenic; and b) when cells are simultaneously treated with MMC and RFR at these same moderate power levels, the RFR does not affect either the inhibition of cell growth or the extent of mutagenesis resulting from the treatment with the chemical MMC alone.
In vitro genotoxicity of dyes present in colored smoke munitions
Authors: Brooks A. L. , Seiler F. A. , Hanson R. L. , Henderson R. F.
Published: February 2007

Genetic toxicology studies were conducted on organic dyes and mixtures used in colored smoke munitions. The dyes studied included Solvent Red 1; two different batches (Lot 1 and Lot 2) of Disperse Red 11; terephthalic acid; and a mixture of 25 parts Solvent Red 1, 5 parts Disperse Red 11, and 16 parts terephthalic acid. The dyes were evaluated for their ability to produce mutations in Salmonella bacterial strains and in Chinese hamster ovary (CHO) cells. The dyes were also tested in CHO cells to determine cytotoxicity and the induction of sister chromatid exchanges and chromosome aberration. None of the dyes were genotoxic in the standard Ames assay using bacterial strain TA1535 or TA100 with or without the addition of S‐9 or in TA98 and TA1538 without S‐9. With S‐9, Disperse Red 11 (Lot 2) showed significant mutagenic activity in TA98 and TA1538 which increased as a function of S‐9 concentration. However, the maximum level of mutagenic activity detected was low (3.8 revertants/μg). The azo dye Solvent Red 1 was also negative in a pre‐incubation assay designed to reduce azo compounds to free amines. Solvent Red 1 was cytotoxic to mammalian cells, caused a significant increase in SCE, but was not mutagenic or clastogenic. Disperse Red 11 (Lot 1 and Lot 2) were not cytotoxic or clastogenic but produced an increase in cell cycle time and SCE frequency. Only Disperse Red 11 (Lot 2) increased mutations in the CHO/hypoxanthine‐guanine phosphoribosyltransferase (HGPRT) assay. The mutagenic activity of the dye mixture was not significant, suggesting no synergistic interaction between the dyes. These studies demonstrated that none of the dyes was clastogenic and that a contaminant in Disperse Red 11 (Lot 2) may be responsible for the weak mutagenic activity in both mammalian and bacterial cell systems.
Increased chromosome fragility as a consequence of blood folate levels, smoking status, and coffee consumption
Authors: Chen Andrew T. L. , Reidy John A. , Annest Joseph L. , Welty Thomas K. , Zhou Huan‐Geng
Published: February 2007

Chromosome fragility in 96 h, low‐folate cultures was found to be associated with smoking status, coffee consumption, and blood folate level. The higher proportion of cells with chromosome aberrations in cigarette smokers was attributable to lower red cell folate levels in smokers compared with nonsmokers. There was a positive linear relationship between the average cups of coffee consumed per day and the proportion of cells with aberrations. This association was independent of the effects of smoking and red cell folate level. These data suggest that smoking history, coffee consumption, and red cell folate level are important considerations for the design and interpretation of fragile site studies in cancer cytogenetics.
Mutagenicity of the human carcinogen treosulphan in Salmonella
Authors: Zeiger Errol , Pagano Dennis A.
Published: February 2007

The human carcinogen treosulphan was mutagenic in Salmonella typhimurium TA100 and TA1535, as was dl‐1,2:3,4‐diepoxybutane (DEB), a proposed hydrolysis product of treosulphan. Another proposed hydrolysis product, methane‐ sulfonic acid, was not mutagenic in these strains. The pattern of the mutagenic responses at pH 6, 7, and 8 to treosulphan and DEB suggests that DEB formation may be responsible for the mutagenicity of treosulphan.
A procedure for data analysis of the rodent micronucleus test involving a historical control
Authors: Hayashi M. , Yoshimura I. , Sofuni T. , Ishidate M.
Published: February 2007

No standard procedure of data analysis for rodent micronucleus tests involving historical controls has been established. In the present paper, under the presumption that the distribution of the historical control is stable and reliable, a procedure with three statistical steps is proposed to analyze the frequency of micronucleated polychromatic erythrocytes (MNPCEs). In the first step, the frequencies of MNPCEs in negative and positive control groups of a current experiment of the micronucleus test are compared with the distribution of historical negative and positive controls to examine the technical validity of the current experiment. In the second step, the frequency of MNPCEs in each treatment group is compared with the distribution of the historical negative control. In the third step, the dose‐response relation is tested with the Cochran‐Armitage trend test. A Monte Carlo simulation study shows that the power of this procedure is acceptable and also this procedure is robust. An application of this procedure on real data reveals that it is effective in detecting clastogenic chemicals when the probability of a type I error is nearly .01.
Initiating carcinogen, triethylenemelamine, induces micronuclei in skin target cells
Authors: He Shuilin , Baker Robert S. U.
Published: February 2007

Keratinocytes from mouse skin were cultured for a short period in vitro following single or multiple treatments at low dose levels in vivo with the known chromosome‐damaging agent triethylenemelamine (TEM). The chemical was applied to the skin of HRA/Skh hairless mice at concentrations corresponding to those reported to initiate cancer in initiation‐promotion assays. A significant dose‐related depression in keratinocyte cell recovery occurred over the dose range 0.3–1 mg TEM/mouse (single or multiple treatments). Under the same conditions, a dose‐related induction of micronuclei was observed using the cytokinesis‐block method with cytochalasin B. A similar frequency of micronuclei was detected in binucleate cells from mice treated with single or multiple applications of TEM. Mice held for 12–48 h post‐treatment, before removal of skin for in vitro culture, yielded highest micronuclei frequencies. These results indicate that the same target cell population, skin keratinocytes, can be used to investigate both genotoxicity and carcinogenesis, and that micronucleus induction in these cells may be a sensitive signal of skin cancer initiation.
Synergistic induction of cytogenetic damage by alkylating antineoplastics and 5‐azacytidine in human lymphocytes
Authors: Loannidou E. , Lialiaris T. , Mourelatos D. , Dozi‐Vassiliades J.
Published: February 2007

We studied the effects of the inhibitor of DNA methylation, 5‐azacytidine (Aza‐C), alone and in combination with three antitumor alkylating agents, on sister chromatid exchanges (SCEs) and lymphocyte proliferation kinetics. Aza‐C was found to act synergistically on induction of SCEs when administered in combination with either melphalan (MEL) or chlorambucil (CBC) or cis‐platinum‐(ll)diamine dichloride (cis‐Pt). Cell‐division delays were consistently observed in cultures treated with each of the antineoplastics when introduced concomitantly with Aza‐C, compared with cultures treated with antineoplastics alone. Mitotic indices (Ml) in cultures treated with each of the three alkylating agents were found to be suppressed by Aza‐C. These results support the premise that hypomethylation of DNA causes cytotoxic effects by interfering with DNA repair mechanisms and by inhibiting DNA synthesis, or other cell growth mechanisms, which human lymphocytes undertake after being damaged by alkylation.
Cytogenetic effects of cigarette smoke on pulmonary alveolar macrophages of the rat
Authors: Rithidech Kanokporn , Chen Bean T. , Mauderly Joe L. , Whorton Elbert B. , Brooks Antone L.
Published: February 2007

To determine accurately the potential genetic damage induced by toxic inhaled agents, the cells that receive a high concentration of such agents should be analyzed. Pulmonary alveolar macrophages (PAMs) represent such cells. We compared the cytogenetic effects of cigarette smoke on PAMs of rats exposed repeatedly by different methods. This study was part of a larger investigation of the health effects resulting from different methods of exposing rats to cigarette smoke. Fischer 344/N male rats (4/group) were randomly selected from five different exposure groups: (1) nose‐only sham‐exposed (air) control, (2) whole‐body sham‐exposed control, (3) nose‐only intermittent, (4) nose‐only continuous, and (5) whole‐body continuous. The rats were exposed 6 hr/day, 5 days/week for 22–24 days. All smoke‐exposed rats received the same daily concentrations x time product (600 mg.hr.m−3 for the first week, 1200 mg.hr.m−3 thereafter) of cigarette smoke. Rats were injected intraperitoneally with colchicine at the end of exposure. PAMs were obtained by lung lavage and chromosomal damage was measured. Highly significant smoke‐induced differences in both structural and numerical aberrations were observed in continuously exposed rats vs. sham controls, regardless route of exposure. The structural aberrations observed were chromatid‐type deletions. Both hypoploid and hyperploid cells were detected. Our data suggest that cigarette smoke is clastogenic and may disrupt spindle‐fiber formation. These activities may play a role in the induction of human carcinogenesis caused by cigarette smoke exposure.
Exposure level monitor of 3‐amino‐1,4‐dimethyl‐5H‐pyrido[4, 3‐b]indole, a dietary carcinogen, in rabbits
Authors: Manabe Shigeo , Kanai Yoshikatsu , Wada Osamu
Published: February 2007

The present investigation describes a method for the detection of minute amounts of 3‐amino‐1, 4‐dimethyl‐5H‐pyrido[4, 3‐b]indole (Trp‐P‐1), a carcinogenic tryptophan pyrolysate, bound to the hemoglobin of erythrocytes and plasma from rabbits dosed orally with the dietary carcinogen. The method consists of the acid‐induced release of the dietary carcinogen adducts as the free carcinogen and their extraction with methylene chloride and subsequent quantitation by high‐performance liquid chromatography (HPLC). With this method, Trp‐P‐1 levels in plasma, platelets, and red blood cells were monitored for 12 weeks to determine a suitable indicator for estimating the exposure levels of the dietary carcinogen. The results suggest that Trp‐P‐1 in red blood cells that bound covalently to the hemoglobin is the most suitable for monitoring the long‐term exposure levels.
Crotonaldehyde is mutagenic in Salmonella typhimurium TA100
Authors: Neudecker Tilman , Eder Erwin , Deininger Christoph , Henschler Dietrich
Published: February 2007

The mutagenicity of crotonaldehyde in Salmonella typhimurium TA100 cannot be demonstrated in the standard plate incorporation assay. However, as reported earlier by our group, this α,β‐unsaturated aldehyde is clearly mutagenic in the liquid assay modification of this testing procedure. Carried out because of the doubts recently expressed by Cooper et al. (Environ Mutagen 9:289–295, 1987) concerning the observed mutagenicity of crotonaldehyde in S. typhimurium TA100, this study confirms that this compound is clearly a direct (without activation by mammalian microsomes)‐acting mutagen in S. typhimurium TA100 under appropriate conditions in the preincubation assay. The observed mutagenicity is increased by extended preincubation time and increased bacterial cell densities.
Cytogenetic analysis of spontaneous and 2‐cyanoethylene oxide‐induced tk —/— mutants in TK6 human lymphoblastoid cultures
Authors: Kodama Yoshiaki , Boreiko Craig J. , Skopek Thomas R. , Recio Leslie
Published: February 2007

Two phenotypic classes of selectable tk —/— mutants have been isolated from the TK6 human lymphoblast cell line; one has a normal growth rate (tkn) relative to the parental cell line; the other has a slow growth rate (tks). Complete karyotypes of metaphase chromosomes were prepared and analyzed from 16 tks mutants (eight spontaneous and eight 2‐cyanoethylene oxide [CNEtO]‐induced), two spontaneous tkn mutants, and the parental TK6 cell line. Southern blot analysis of these tk —/— mutants indicated that all had lost a 14.8 kb polymorphic band corresponding to the active tk allele. No chromosome abnormalities with respect to the parental cell line TK6 were observed in eight spontaneous tks mutants. Chromosome abnormalities that may have been related to CNEtO treatment were observed in four of eight CNEtO mutants. However, chromosome 17, containing the tk locus in man, was cytologically normal with respect to the parental TK6 cell line in 15 of 16 tks mutants. A visible abnormality of chromosome 17 was present in one CNEtO‐induced tks mutant. The abnormality was a duplication of the long arm of the chromosome 17, with break points at q11 and q21. The latter break point is close to the site of the tk locus, suggesting that the aberration observed may be associated with tk —/— phenotype. These observations contrast with the relatively high incidence (>59%) of chromosome 11 abnormalities reported in tks (small colony) mouse lymphoma L5178Y/TK + / — mutants.
Chemical mutagenesis testing in Drosophila. VI. Interlaboratory comparison of mutagenicity tests after treatment of larvae
Authors: Valencia R. , Mason J. M. , Zimmering S.
Published: February 2007

Previous publications on the National Toxicology Program (NTP)‐sponsored mutagenicity testing program in Drosophila dealt with evaluations of chemicals following adult treatment (feed, injection). The current paper deals with a comparison between the laboratories at Brown University (BRU) and the University of Wisconsin at Madison (UWM) regarding the response of larvae to treatment with chemicals in the sex‐linked recessive lethal (SLRL) test and, where appropriate, the reciprocal translocation test as well. Dimethylnitro‐samine (DMN) and dimethylbenz(a)anthracene were used first as reference mutagens. Six coded compounds were then evaluated regarding their repeatability in the two laboratories; the compounds were benzo(a)pyrene, 3‐methylcholan‐threne, coumarin, quinoline, formaldehyde, and 9‐aminoacridine. It was concluded that at this time it would be imprudent to forgo larval treatment in cases where compounds proved negative after adult feeding. Accordingly, testing a series of 20 compounds negative after adult treatment is in progress.
Chemical mutagenesis testing in Drosophila. VII. Results of 22 coded compounds tested in larval feeding experiments
Authors: Zimmering S. , Mason J. M. , Valencia R.
Published: February 2007

Twenty‐two chemicals were tested for mutagenicity in the sex‐linked recessive lethal (SLRL) mutation assay after being fed to Drosophila melanogaster larvae. One compound, maleic hydrazide, was found to be mutagenic. It was tested for the ability to produce reciprocal translocations (RTs) and was positive in that assay as well.
Biotesting of wastewater: A comparative study using the Salmonella and CHO assay systems
Authors: Waters L. C. , Schenley R. L. , Owen B. A. , Walsh P. J. , Hsie A. W. , Jolley R. L. , Buchanan M. V. , Condie L. W.
Published: February 2007

Means to assess the toxicity of wastewaters are essential to implementing the Federal Clean Water Act. Health risk assessment based on single chemicals is limited by the number of chemicals that can be identified and to those chemicals for which toxicity data are available. Long‐term whole animal tests on large numbers of waste‐water samples are not practical. In this study, two short‐term tests, the Salmonella mutagenicity assay and the Chinese hamster ovary (CHO) cell assay for mutagenicity and cytotoxicity, were evaluated as potentially useful biomonitors of wastewaters. Standard assay protocols were modified to allow testing of up to 2.5 and 3.4 ml of unconcentrated water in the bacterial and mammalian cell tests, respectively. Cytotoxicity and mutagenicity were detected in some unconcentrated wastewater samples using these modifications. Data on eight wastewater samples, representing five different sites, indicated that the Salmonella test is the more sensitive indicator of mutagenic activity in those samples, whereas the CHO test is a sensitive indicator of the presence of cytotoxic components. Wastewater concentrates, prepared by adsorption onto XAD‐2 and “blue cotton,” were compared in the two bioas‐says. In a single concentrate, the two short‐term tests detected distinctly different mutagens. Advantages of using the CHO‐AS52 cell line instead of the CHO‐K1BH4 line for detecting wastewater mutagens were indicated. This study illustrates the complementary use of multiple bioassays and concentration methods to detect and characterize toxic components in wastewater.
Induction of prophage lambda by chlorophenols
Authors: Demarini David M. , Brooks Harold G. , Parkes Douglas G.
Published: February 2007

Chlorinated phenols, which are used primarily as wood preservatives and fungicides, are present in most air, water, and soil samples in industrialized areas as well as in the urine of most people. We have examined the ability of phenol and the 19 isomers of chlorophenol to induce DNA damage using the Microscreen prophage‐induction assay in Escherichia coli. Seven of the isomers (2,3,4,‐tr, 2,4,5‐tri, 3,4,5‐tri, 2,3,4,5‐tetra, 2,3,6‐tri, 2,4,6‐tri, and pentachlorophenol) induced prophage lambda in the presence of S9, with the first three being ∼ 10 times more potent than the last three. The more potent isomers have either one or no chlorine atom ortho to the OH group; whereas the less potent isomers have two chlorine atoms ortho to the OH group. Although none of the 20 compounds is mutagenic in Salmonella, the prophage‐induction results agree with findings by others that most of these seven isomers are clastogenic, are associated with cancer and chromosomal aberrations in humans (pentachlorophenol), and are carcinogenic in radents (2,4,6‐tri and pentachlorophenol). A likely basis for the genotoxicity of the seven isomers involves the metabolism of the parent isomer to a chlorohydroquinone, which can form a chlorobenzosemiquinone in the presence of oxygen. These two metabolites can produce free radicals that can cause DNA strand breaks, resulting in prophage induction in E. coli or, possibly, the chromosomal aberrations/cancer associated with human exposure to chlorophenols.
LUMO Energies and hydrophobicity as determinants of mutagenicity by nitroaromatic compounds in Salmonella typhimurium
Authors: Lopez de Compadre Rosa L. , Debnath Asim Kumar , Shusterman Alan J. , Hansch Corwin
Published: February 2007

Quantitative structure‐activity relationships have been derived for the mutagenic activity of 47 nitroaromatic compounds acting on Salmonella typhimurium (TA100) and 66 acting on TA98. The mutagenicity is linearly dependent on the energy of the lowest occupied molecular orbital and bilinearly dependent on the hydrophobicity (octanol/water log P) of the mutagens. The mechanism of action is considered in the light of these findings.
Urine mutagenicity and biochemical parameters as markers of exposure to petroleum pitch using a rat model
Authors: Pasquini R. , Monarca S. , Sforzolini G. Scassellati , Savino A. , Fatigoni C. , Puccetti P.
Published: February 2007

A petroleum pitch sample collected in a carbon electrode factory was studied using a series of in vivo assays for genotoxicity and enzymatic induction capability. Rats were treated with the petroleum derivative in three doses: 100, 50, and 10 mg/kg body weight. The treatment produced a rapid excretion of mutagenic substances in the urines of the first 24 hr only in rats treated with high doses (100 and 50 mg/kg). No faecal mutagenic activity was observed. Analyses of urinary thioethers showed that urinary metabolites derived from the compounds present in the pitchsample at the lowest doseadministered (10 mg/kg) were eliminated primarily as cysteine conjugates. The pitch sample was found to be a good inducer of pulmonary and hepatic aryl hydrocarbon hydroxylase, especially after a 50 mg/kg dose. Urinary D‐glucaric acid content was always statistically increased in treated animals compared with controls, confirming the enzymatic induction activity. Hepatic glutathione‐S‐transferase activity increased following treatment with 50 and 10 mg/kg doses.
Genotoxic effects of five polycyclic aromatic hydrocarbons in human and rat mammary epithelial cells
Authors: Mane Suneeti S. , Purnell Dallas M. , Hsu Ih‐Chang
Published: February 2007

Five polycyclic aromatic hydrocarbons (PAHs) of different carcinogenic activities were evaluated for their effects on DNA synthesis (3HTdR labeling index (L.I.)) of rat and human mammary epithelial cells (MEC) and for their effects on chromosomes in MEC‐mediated sister chromatid exchange (SCE) assays. When compared with DMSO‐treated cells, exposures of rat MEC to the two most potent carcinogens (5 μg/ml for 24 hr), i.e., 7,12‐dimethylbenz(a)anthracene (DMBA) and benzo(a)pyrene (B[a]P), resulted in a 45‐62% reduction in the L.I. of rat MEC. Another carcinogen, 20‐methylcholanthrene (MCA), produced a 35‐48% reduction in L.I., while the noncarcinogenic PAHs, 1,2‐benzanthracene (BA) and benzo(e)pyrene (B[e]P), showed no effect. Similarly, exposures of human MEC to DMBA and B[a]P resulted in a 50‐90% depression in L.I. while BA was significantly less effective (30% reduction). When cocultivated with Chinese hamster V‐79 cells in the presence of PAH,both rat and human MEC can activate and release the active metabolites to induce SCE in V‐79 cells. In the rat MEC‐mediated assay for all 5 PAHs, the frequencies of SCE per chromosome in DMBA‐, B[a]P‐, MCA‐, BA‐, B[e]P‐, and DMSO (solvent control)‐treated groups were 6, 3, 1.4, 0.7, 0.4, and 0.3, respectively. DMBA was most effective in increasing SCE, while B[e]P was ineffective. In the human MEC‐mediated assay, B[a]P was more effective than DMBA in inducing SCE, and the frequencies of SCE per chromosome were 4.5 and 3.6 in B[a]P‐ and DMBA‐treated groups, respectively. Comparing depression of L.I., SCE, and in vivo carcinogenecity for the 5 PAHs, SCE mediated by rat MEC is better correlated with carcinogenecity in rat than L.I. depression.
Comparison of three assays for genetic effects of antineoplastic drugs on cancer patients and their nurses
Authors: Krepinsky A. , Bryant D. W. , Davison L. , Young B. , Heddle J. , McCalla D. R. , Douglas G. , Michalko K.
Published: February 2007

Three assays have been compared for their ability to detect genetic damage caused by antineoplastic drugs in cancer patients and possible damage in the nurses who administered these drugs. The assays were sister chromatid exchanges (SCE) and chromosomal aberrations in peripheral blood lymphocytes, and the Salmonella/mammalian microsome assay on urine. Three comparisons were made: 1) patients before versus after treatment; 2) the administering nurses immediately after their work period versus after a few days off that followed (work and off‐work); 3) the exposed nurses versus other nurses who did not administer antineoplastic drugs (controls).

The SCE assay detected the treatments in all eight patients from whom complete data were obtained, and was positive in two nurses with a long history of smoking. The Salmonella/mammalian microsome assay detected eight of ten treatments in patients but failed to detect smokers. Four of nine patients receiving treatment were detected by the analysis of chromosomal aberrations.

The SCE assay did not distinguish between the work and off‐work samples in either the exposed or control nurses. The exposed nurses, as a group, had slightly fewer SCEs than the controls due to the two smokers detected 'n the latter group. Chromosomal aberration was the only assay which showed significant difference between the two samples of the exposed nurses and, consequently, between the exposed and control nurses. These differences, however, arose primarily from a higher frequency of aberrations found among the exposed nurses in samples taken after a few days away from work, rather than at the end of their work period. There is no evidence that the increase was connected to occupational exposure.
Comparative studies on the genotoxic activity of mainstream smoke condensate from cigarettes which burn or only heat tobacco
Authors: Doolittle D. J. , Lee C. K. , Ivett J. L. , Mirsalis J. C. , Riccio E. , Rudd C. J. , Burger G. T. , Hayes A. W.
Published: February 2007

The in vitro genotoxic activity of mainstream cigarette smoke condensate (CSC) from cigarettes which heat but do not burn tobacco was compared to that of CSC from cigarettes which burn tobacco. CSCs from five cigarettes were compared. Three of the cigarettes [the Kentucky reference research cigarette (1R4F), a commercially available ultra‐low tar brand (ULT) and a commercially available ultra‐low tar menthol brand (ULT‐menthol)] burn tobacco while two of the cigarettes [a regular (TEST) and a menthol (TEST‐menthol)] heat tobacco. CSC from all cigarettes were collected by identical standard techniques, which involved collecting mainstream smoke particulate matter on Cambridge filter pads under FTC smoking conditions. The pads were extracted with DMSO, and the CSCs obtained [10 mg total particulate matter (TPM)/ ml DMSO] were evaluated at identical concentrations in an in vitro genetic toxicology test battery. CSCs from 1R4F, ULT, and ULT‐menthol cigarettes were mutagenic in Ames bacterial strains TA98, TA100, TA1537, and TA1538 in the presence of metabolic activation (S9 from Aroclor‐induced rat liver) but negative in strain TA1535. In the absence of metabolic activation, 1R4F, ULT, and ULT‐menthol CSCs were not mutagenic except for a weak response in strain TA1537 for the 1R4F and ULT CSCs. TEST and TEST‐menthol CSCs were nonmutagenic in all five bacterial strains, both with and without metabolic activation. CSCs from 1R4F, ULT, and ULT‐menthol cigarettes were positive in the CHO‐chromosomal aberration assay and in the CHO‐sister chromatid exchange assay both with and without metabolic activation while TEST and TEST‐menthol CSCs were negative in both assays, either with or without metabolic activation. CSCs from 1R4F, ULT, and ULT‐menthol cigarettes were weakly positive in inducing DNA repair in cultured rat hepatocytes while TEST and TEST‐menthol CSCs were negative in this assay. All five CSCs were nonmutagenic in the CHOHGPRT assay both with and without metabolic activation. CSCs from the 1R4F, ULT, and ULT‐menthol cigarettes were cytotoxic in the CHOHGPRT assay, both with and without metabolic activation, while TEST and TEST‐menthol CSCs were not cytotoxic under either condition. These results demonstrate that mainstream CSCs from the TEST and TEST‐menthol cigarettes are neither genotoxic nor cytotoxic under conditions where CSCs from 1R4F, ULT, and ULT‐menthol cigarettes are genotoxic and/or cytotoxic in a concentration‐dependent manner.