ISSN:0192-2521    

DOI:10.1002/em.2860050202

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1983

数据来源: WILEY

摘要:

AbstractThe Tradescantia‐Micronucleus (Trad‐MCN) bioassay was utilized to determine the genotoxicity of Malathion, a common insecticide. Four different treatment procedures were applied: a) absorption of Malathion/water mixture (with or without DMSO and/or S‐9) through the stem, b) spraying a Malathion/water mixture onto the plant cuttings in enclosed chambers, c) spraying a Malathion/ water mixture on an open population of plants in the greenhouse, and d) absorption of Malathion fumes through the leaves and buds. Most treatments were administered for 6 hr, followed by a 24‐hr recovery time. Slides were prepared from the samples and scored for micronucleus (MCN) frequencies. Results of 16 experiments indicated that the genotoxicity of liquid Malathion absorbed through the stem was very low and often masked by high toxicity, causing dead cells in the stem, leaves, and meiocytes. Malathion spray at the dosage of 0.435% in an enclosed chamber or on an open population of plants yielded negative responses. Malathion fumes at dosages of 0.15–0.25% induced signficantly higher (0.05) MCN frequencies above the controls and altered the nuclear structure to form unequal sized nuclei and multiple breaks in each of the four cells of a tetrads. It also caused degeneration of nuclei, “protrusions on nuclei,” and inhibition of cell growth. Higher dosages (above 0.25

ISSN:0192-2521    

DOI:10.1002/em.2860050203

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1983

数据来源: WILEY

摘要:

AbstractConsiderable attention is currently being given to the roles of environmental and endogenous mutagens in tumor induction and in tumor progression through the abilities of mutagens to induce one or another kind of somatic mutation. It is proposed here that mutagens, also through induction of somatic mutations, initiate a spectrum of additional, much more common, focal lesions that are important to the human condition. While individually they are of relative insignificance and thus neglected by many clinicians, the functional attributes of these focal lesions have important impacts on human physiology and thus contribute substantially to the process of aging. Additionally, one individual focus may progress to an extent that it produces clinically recognizible symptoms and may even jeopardize the carrier's life. The ultimate and developed expression of these lesions is heterogeneous, is far removed in time from initial induction, and relies on additional host and environmental factors for expression; therefore, the possible role of somatic mutation is readily overlooked. The focal lesions reviewed are fibrous atherosclerotic plaques, senile cataracts, and metaplasias. Literature that implicates metaplasias as precursor or as predisposing lesions in the ultimate formation of gallstones, duodenal ulcers, and adenocarcinomas is summarized.

ISSN:0192-2521    

DOI:10.1002/em.2860050204

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1983

数据来源: WILEY

摘要:

AbstractEthyl methanesulfonate was tested for its ability to induce viable heritable translocations in progeny of male rats given a single IP injection prior to breeding. Reproductively competent Wistar rats were used as the test animals. Males were treated with either 75 or 150 mg/kg EMS or vehicle control. Neonates were used for primary tissue culture; the fibroblasts were harvested for cytogenetic analysis of chromosomes banded by Giemsa banding procedures. Since the cells examined were somatic cells, it was necessary to karyotype only two to three per neonate to ascertain inherited translocations. A reduction in fertility was observed in males treated with EMS. A statistically significant (p<0.05) dose‐related increase in heritable translocations was observed in the F1generation of treated animal

ISSN:0192-2521    

DOI:10.1002/em.2860050205

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1983

数据来源: WILEY

摘要:

AbstractWe have observed quantitative and qualitative differences in the mutability and mutagen‐specificity of various drug‐resistance marker loci in Chinese hamster ovary (CHO) cells, which suggest that mammalian gene loci may differ in their relative mutability by a given mutagenic agent. We have used the CHO‐AT3–2 multiple‐marker mutagenesis assay system to examine the dose‐dependent induction and kinetics of expression of mutations at four well‐characterized, drugresistance marker loci, after treatment with chemical agents which produce various types of DNA damage. The CHO‐AT3–2 subline allows simultaneous quantitation and direct comparison of induced mutation frequencies at thehgprt, oua(Na+/K+ATPase),aprt, andtkloci. The agents tested in this study included ethyl methanesulfonate, methyl methanesulfonate, mitomycin C, ICR‐191, benzo[a]pyrene, and dimethylnitrosamine. The expression kinetics and optimal expression times for each drug‐resistance marker were determined in dose‐response experiments in which cells from mutagen‐treated populations were plated at 1‐2‐day intervals over a period of 10 days following mutagenesis. Comparison of induced mutation frequencies for each drug‐resistance marker after mutagen treatments yielding equivalent cell survivals (equitoxic doses resulting in relative cell survivals of 0.37) revealed locus‐specific differences in the relative mutagenicities of the agents tested. These results indicate that the apparent mutagenicity of a particular agent at a single genetic locus may not necessarily be an accurate indicator of that agent's mutagenic po

ISSN:0192-2521    

DOI:10.1002/em.2860050206

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1983

数据来源: WILEY

摘要:

AbstractPeroxyacetic (PAA) and monoperoxydecanoic (MPDA) acids were assayed for induction of unscheduled DNA synthesis (UDS) by liquid scintillation counting of hot‐acid‐extractable DNA and by light microscope autoradiography. Both compounds were also assayed for induction of DNA repair synthesis by differential density labeling ultracentrifugation. Uniformly negative results were obtained for MPDA. Conflicting results were obtained for PAA using the UDS techniques. Negative results were consistently obtained, however, in three separate assays using two different PAA samples with the more definitive differential density DNA repair synthesis technique. Hydrogen peroxide, which is present as a contaminant in the PAA samples, was also assayed for induction of UDS by autoradiography and for induction of DNA repair synthesis by differential density labeling. Our results with this compound are in agreement with published data and were consistently positive using both techniques. We conclude that neither MPDA nor PAA induce DNA repair synthesis and suggest that the conflicting PAA results may be due to the presence of hydrogen peroxide in commercial samples of

ISSN:0192-2521    

DOI:10.1002/em.2860050207

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1983

数据来源: WILEY

摘要:

AbstractThe mutagenic/carcinogenic potential of four commercial accelerators were evaluated using a battery of in vitro assays. All of these compounds were mutagenic in one or more assays. Positive responses were noted in the Escherichia coli pol A+/pol−/pol A‐ DNA repair, mouse lymphoma L5178Y TK+/− forward mutation, BALB/3T3 cell transformation, and CHO cell chromosome aberration assays. In contrast to previous studies of accelerators, no mutagenic response was observed in the E coli WP2uvrA‐ assay or in any of the Salmonella typhimurium strains tested. These studies have indicated that rubber accelerators should be regarded as potential human health hazards and that further in vitro and in vivo studies are needed to assess the potential genetic hazards of this large class of ch

ISSN:0192-2521    

DOI:10.1002/em.2860050208

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1983

数据来源: WILEY

摘要:

AbstractSorbic acid and potassium sorbate are widely used Generally Recognized as Safe (GRAS) food additives with an extremely high (25 mg/kg) acceptable daily intake level. Some children between the ages of 6–24 months may actually ingest this amount. While presently not permitted to be added directly to meat and poultry products in the US, potassium sorbate has been proposed as a preservative for bacon, as an additive in conjunction with nitrite and ascorbate or erythorbate. Sorbate and nitrite form several species of direct‐acting mutagens and genotoxic agents when present together at pH's mimicking gastric conditions. Two of the mutagens have been identified as ethylnitrolic acid and 1,4‐dinitro‐2‐methylpyrrole. Mutagen formation is blocked by ascorbate at low pH. Ascorbate at eightfold molar excess leads to inactivation of 1,4‐dinitro‐2‐methylpyrrole near neutral pH but does not destroy the mutagenic nitro compound at low pHs. The combination of sorbate with nitrite represents a potential health risk in the absence of adequate inactivating levels of ascorb

ISSN:0192-2521    

DOI:10.1002/em.2860050209

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1983

数据来源: WILEY

ISSN:0192-2521    

DOI:10.1002/em.2860050210

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1983

数据来源: WILEY

摘要:

AbstractDi‐(2‐ethylhexyl)phthalate (DEHP) and its two major metabolites, mono‐(2‐ethylhexylhexyl)phthalate (MEHP) and 2‐ethylhexanol (EH), were evaluated for their ability to induce chromosomal damage in male Fischer 344 rats after oral administration. Dose levels, the highest of which represents one‐tenth of the five‐day LD50, were based on a preliminary five‐day dose‐finding study for each test material. The dose levels selected were 5.0, 1.7, and 0.5 ml/kg/day for DEHP; 0.14, 0.05 and 0.01 ml/kg/day for MEHP; and 0.21, 0.07 and 0.02 ml/kg/day for EH. All test materials and vehicle control (corn oil) were administered by gavage for five consecutive days. A triethylenemelamine (TEM)‐positive control group received a single intraperitoneal injection of 0.5 mg/kg TEM one day prior to sacrifice. Of the 50 metaphase bone marrow cells examined from each animal, no significant increase in chromatid and chromosome breaks or structural rearrangements were noted for DEHP, MEHP, and EH. In addition, the mitotic index, determined from 100 cells per animal, was unaffected by DEHP, MEHP, or EH. The results of this investigation indicate that DEHP, MEHP, and EH, at these dose levels, did not induce detectable chromosomal aberrations after

ISSN:0192-2521    

DOI:10.1002/em.2860050211

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1983

数据来源: WILEY