2-Acetylaminofluorene is used by scientists to study the carcinogenicity and mutagenicity of aromatic amines and as a positive control in the study of liver enzymes. 2-Acetylaminofluorene was intended for use as a pesticide but was never marketed because of its carcinogenicity in experimental animals.2-Acetylaminofluorene is reasonably ...
NSDL National Science Digital Library
2-Acetylaminoflorene, 4-acetylaminofluorene, benzo(a)pyrene and pyrene were evaluated in the rat liver foci bioassay for their ability to initiate gamma-glutamyltranspeptidase-positive foci. Under the conditions used, 2-acetylaminofluorene and benzo(a)pyr...
National Technical Information Service (NTIS)
The carcinogenic activity of 2-acetylaminofluorene (2-AAF) in mice and rats has been accurately described so that it is a suitable archetypical chemical for investigations of parameters of cross-species variation. The results of the study supported a pharmacokinetic model that re...
EPA Science Inventory
...CONTINUED) OCCUPATIONAL SAFETY AND HEALTH STANDARDS (CONTINUED) Toxic and Hazardous Substances § 1910.1014 2-Acetylaminofluorene. See § 1910.1003, 13 carcinogens. [61 FR 9245, Mar. 7,...
Code of Federal Regulations, 2011
A new technique for the conversion of 2-acetylaminofluorene and several ring-hydroxylated metabolites to mono- and di-tert.-butyldimethylsilyl derivatives was developed to permit their analysis by gas chromatography-mass spectrometry in order to quantify the metabolism of 2-acetylaminofluorene incubated in freshly isolated rat hepatocytes. This new gas ...
Energy Citations Database
Male and female Sprague-Dawley rats were treated by gastric intubation either 1, 2, 3 or 4 times at biweekly intervals with 10 mg/kg doses of the hepatocarcinogen of (ring(sup 3)H)-N-hydroxy-2-acetylaminofluorene (AF) and acetylaminofluorene (AAF) adducts...
...Benzidine, (k) 4-Aminodiphenyl, (l) Ethyleneimine, (m) Beta-propiolactone, (n) 2-Acetylaminofluorene, (o) 4-Dimethylaminobenzene, and (p)...
Code of Federal Regulations, 2010
We have computed the total energy surface as a function of two important torsion angles of the carcinogen N-2-acetylaminofluorene (AAF) bonded to the carbon C8 of deoxyguanosine using the semiempirical quantum mechanical method MNDO. One global minimum and one local minimum are found separated by an appreciable barrier. The equilibrium geometries show the rearrangement of AAF ...
NASA Astrophysics Data System (ADS)
The two carcinogens, benzo(a)pyrene (BP), and 2-acetylaminofluorene (2AAF), and their respective noncarcinogenic analogs, pyrene (PYR) and 4-acetylaminofluorene (4AAF), were tested for induction of presumed dominant-lethal effects in female mice. Each che...
The structure of an adduct between guanine and the carcinogen acetylaminofluorene has been examined in the solid state by X-ray crystallography, and in solution by NMR techniques. The observed conformations have been compared with predictions from energy calculations and their relevance to models of adducts with DNA has been examined.
PubMed Central
mutagens are saccharin and aflatoxin B1. When we remove these from the correlation, Pearson's correlation-acetylaminofluorene; AFB, aflatoxin B1; SAC, sac- charin. Chemicals plotted, and their carcinogenic and muta- genic potencies are, respectively: 2-acetylaminofluorene, 1.19, 949.2; 2-aminoanthraquinone, 0.01, 56.0; aflatoxin
E-print Network
We used colony probe hybridization procedures-to determine the mutations in 600 revertants of the -1 frameshift allele hisD3052 and 200 revertants of the base substitution allele hisG46 of Salmonella typhimurium induced by 2-acetylaminofluorene (2-AAF) in the presence of S9. -AAF...
the total energy as a function of six important torsion angles of the carcinogen N-2-acetylaminofluorene between the two minima. Key words: deoxyguanosine, N-2-acetylaminofluorene, AAF, carcinogen, AM1 1. Introduction During the last four decades the carcinogenic effect of aromatic amines has been firmly
The overall objective of this experiment was to determine the molecular mechanism by which N-hydroxy-2-acetylaminofluorene (N-hydroxy-AAF) induces mutations in the Salmonella/microsome assay system. To accomplish this objective, the following specific aim...
Acetylaminofluorene-labeled genomic DNA probes were used for the identification and classification of Campylobacter strains. Relationships among 17 well-known strains of Campylobacter species and subspecies were studied by comparing acetylaminofluorene- or 32P-labeled probes. Results obtained with both methods were closely correlated and were in agreement ...
PubMed
A competitive enzyme immunoassay using a bispecific monoclonal antibody (Bi-MAb) was developed to quantify acetylaminofluorene (AAF) adducts fixed on DNA and then compared to the spectrophotometric method. It was shown that this simple method allowed the measurement of as low as 2 pmol per assay of AAF bound to DNA. This technique was used to monitor synthesis and purification ...
Excision repair after combined treatments of uv and N-acetoxy-2-acetylaminofluorene (AAAF) was studied by three different techniques in cells proficient in uv excision repair and in cells deficient in uv repair. Two patterns of repair were observed: in re...
The metabolism and mutagenicity of 1-nitropyrene, 1-aminopyrene, 2-aminofluorene and acetylaminofluorene in hepatic cell cultures is investigated. Metabolic products were assayed by thin-layer chromatography. Ancillary studies on Ames' assary mutagencity ...
Changes in the hepatic drug/xenobiotic-metabolizing enzymes in underfed rats exposed to aflatoxin B/sub 1/ and N-acetylaminofluorene were investigated. Neither carcinogen, fed at the level of 10 ..mu..g and 0.667 mg per 100 g body weight, respectively, over a period of 3 wk, had any significant influence on cytochrome P-450 and aryl hydrocarbon hydroxylase in the ...
Three techniques were used to examine excision repair in human cells treated with ultraviolet radiation, N-acetoxy-2-acetylaminofluorene, and a combination of the two. The three techniques gave similar results. Two types of human cells were used: (a) excision repair proficient (normal human fibroblasts and xeroderma pigmentosum variants); and (b) excision repair deficient ...
Earlier experiments on human cells showed that N-acetoxy-2-acetylaminofluorene mimics ultraviolet radiation in biological and repair characteristics and that the amount of repair from a combined treatment was additive. Chinese hamster V-79 cells are less proficient than human cells in excision repair of pyrimidine dimers resulting from irradiation. We therefore investigated ...
Give different dose levels of 2-acetylaminofluorene (2-AAF) were fed to weanling mice of four different genotypes from three unrelated F1 hybrids for 13 weeks to determine differences in susceptibility to induction to bladder hyperplasia. Differences in t...
Minimized semi-empirical potential energy calculations for a number of carcinogen adducts with dCpdG have yielded molecular views of the adduct conformations. The base displaced and Z type conformations of acetylaminofluorene (AAF) adducts to guanine C-8 ...
Tests were made on male and female albino rats that were fed 0.1% acetylaminofluorene, and examinations carried out on the influence of a simultaneous fractionated total betatron irradiation and vitamin B/aub 12/ injections given at the same time. The simultaneously applied fractionated betatron treatment seems to check the development of liver carcinoma induced by ...
A new model is presented for acetylaminofluorene (AAF)-modified Z-DNA, in which the carcinogen is in a base-displaced position, inserted into the helix interior and parallel with an adjacent base. 18 references, 3 figures.
...Ethyleneimine, (m) Beta-propiolactone, (n) 2-Acetylaminofluorene, (o) 4-Dimethylaminobenzene, and (p) N-Nitrosodimethylamine. Air Quality�Surface Only [Reserved] Air Quality�Underground...
Several carcinogenic metabolites of the carcinogen 2-acetyl-aminofluorene, especially 2-nitrosofluorene and N-hydroxy-2-aminofluorene, are potent frameshift mutagens for Salmonella typhimurium. 2-Nitrosonaphthalene, 2-nitrosophenanthrene, 4-nitroso-trans-stilbene, 4-nitrosobiphenyl, and 4-nitrosoazobenzene, all of which are metabolites or likely metabolites of carcinogenic ...
We have computed the total energy as a function of six important torsion angles of the carcinogen N-2-acetylaminofluorene (AAF) bonded to the nitrogen N2 of deoxyguanosine using the semiempirical quantum mechanical method AM1. One global minimum and one local minimum are found separated by a modest barrier. We have computed the normal-mode frequencies of the relevant torsional ...
Bovine serum albumin (BSA) catalyzes the o-rearrangement of the reactive electrophile, N-sulfooxy-2-acetylaminofluorene (NSF), a potential ultimate hepatocarcinogen in the rat, to the nonmutagenic sulfuric acid esters of 1- and 3-hydroxy-2-acetylaminofluorene. Conversion of NSF was proportional to BSA concentrations ranging from 0.25 to approximately 4 mg ...
We have examined two methods of preparation of DNA adducts from phi X174 RF DNA modified by (/sup 3/H)N-acetoxy-2-acetylaminofluorene ((/sup 3/H)NA-AAF) or N-hydroxy-2-aminofluorene ((/sup 3/H)N-OH-AF). Hydrolysis by enzymes (DNase I, snake venom phosphodiesterase and alkaline or acid phosphatase) and subsequent reverse phase h.p.l.c. of phi X174 RF DNA treated with (/sup ...
Sulfation activity towards N-hydroxy-2-acetylaminofluorene and 4-nitrophenol was determined in male rat liver cytosol at several time points after partial hepatectomy corresponding to G{sub 1}-, S-, and M-phase. N-hydroxy-2-acetylaminofluorene sulfation activity decreased by 80% when hepatocytes entered the G{sub 1}-phase. This lower activity was ...
In normal human cells the amount of excision of ultraviolet damage to DNA saturates at high doses. In these cells some chemicals mimic ultraviolet damage as far as their biological and repair characteristics are concerned. One of these chemicals is N-acetoxy-2-acetylaminofluorene. We determined whether the limited repair capacity for ultraviolet damage was affected by ...
The two carcinogens, benzo(a)pyrene (BP), and 2-acetylaminofluorene (2AAF), and their respective noncarcinogenic analogs, pyrene (PYR) and 4-acetylaminofluorene (4AAF), were tested for induction of presumed dominant-lethal effects in female mice. Each chemical was administered as a single intraperitoneal injection using the maximum dose that could be given ...
We have focused on the cytochrome P450 system since most chemicals require metabolism before being mutagenic or carcinogenic. The cytochrome P450 system is a super gene family of proteins and preliminary in vivo data in humans suggest that variability in the expression of particular isozymes is linked to certain types of cancer. Therefore as an initial attempt to establish the contribution dietary ...
An in vivo test was used to measure induced unscheduled DNA synthesis (UDS) in the germ cells of male mice exposed to the chemicals. Early spermatids, a DNA-repair competent stage, were used to test the effects of 2-acetylaminofluorene (2-AAF), 4-acetylaminofluorene, (4-AAF), benzopyrene (BP), pyrene (PYR), and methyl methanesulfonate. Neither the two ...
Excision repair after combined treatments of uv and N-acetoxy-2-acetylaminofluorene (AAAF) was studied by three different techniques in cells proficient in uv excision repair and in cells deficient in uv repair. Two patterns of repair were observed: in repair proficient cells total repair was additive, and in repair deficient cells total repair was much less than ...
DOE Information Bridge
High-pressure liquid chromatography and the Salmonella/microsome mutagenicity test was used to look for mutagenic impurities in 11 carcinogens and noncarcinogens. Because of the million-fold range in mutagenic potency observed in the Salmonella test, even trace amounts of potent mutagenic impurities in a nonmutagenic compound could be detected. The mutagenicity of ...
Groups of 96 female mice were given 2-Acetylaminofluorene (2-AAF) in their diet at either 100 ppm or 500 ppm until they were removed from the experiment or terminally sacrificed. Control groups of 986 mice/group were also used. Two types of exfoliative ce...
New structures are presented for AF and AAF modified DNAs that place the carcinogen in the minor groove of a B-DNA helix. These structures employ non-Watson-Crick base pairing schemes with syn guanine at the modification site. 32 refs., 9 figs.
Experiments were conducted to study the transplacental and translactational passage and distribution of radiolabeled N-OH-2-AAF in the BALB/c mouse. The radiolabeled N-OH-2-AAF radily crossed the placenta to the fetuses when the compound was administered ...
Analysis of N-(deoxyguanosin-8-yl)-2-acetylaminofluorene (dG-C8-AAF) and N-(deoxyguanosin-8-yl)-2-aminofluorene (dG-C8-AF) by thermospray mass spectrometry (TSP/MS) provided (MH)+ ions. TSP/MS/MS of the (MH)+ ions produced (BH2)+ ions.
Analysis of N-(deoxyguanosin-8-yl)-2-acetylaminofluorene (dG-C8-AAF) and N-(deoxyguanosin-8-yl)-2-aminofluorene (dG-C8-AF) by thermospray mass spectrometry (TSP/MS) provided (MH)+ ions. TSP/MS/MS of the (MH)+ ions produced (BH2)+ ions....
Groups of male rats were dosed concomitantly with 2-AAF by gavage at doses between 0.01 mg/kg and 40 mg/kg, and livers sampled 2-72h later. he liver of one group of animals was perfused to yield hepatocytes which were assayed in vitro for unscheduled DNA synthesis (UDS) via incor...
The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...
Our objective, has been to elucidate on a molecular level, at atomic resolution, the structures of DNAs modified by 2-aminofluorene and its N-acetyl derivative, 2-acetylaminofluorene (AAF). The underlying hypothesis is that DNA replicates with reduced fid...
We have focused on the cytochrome P450 system since most chemicals require metabolism before being mutagenic or carcinogenic. The cytochrome P450 system is a super gene family of proteins and preliminary in vivo data in humans suggest that variability in ...
An in vivo test was used to measure induced unscheduled DNA synthesis (UDS) in the germ cells of male mice exposed to the chemicals. Early spermatids, a DNA-repair competent stage, were used to test the effects of 2-acetylaminofluorene (2-AAF), 4-acetylam...
It is concluded that bladder explants of the human, dog, monkey, hamster, and rat metabolize AAF mainly to ring-hydroxylated products, but also form small amounts of the proximate carcinogenic metabolite N-hydroxy-AAF. Neither the overall binding of AAF to bladder DNA, nor the fo...
Enzyme-altered foci and nodules have been observed in the liver of rats treated with diethylnitrosamine(DENA) followed by selection with 0.02% 2-acetylaminofluorene (2-AAF) and a partial hepatectomy (PH) (DENA-2AAF-PH treatment). The authors determined the effect of subsequent ad...
A computer program is described which simulates the promotion of hepatic carcinogenesis by phenobarbital in a rat population homogeneous in vulnerability to the initiating effects of 2-acetylaminofluorene. Results compare favorably with experimental data in terms of maximal percentage of rats with tumors and the suggestion of phenobarbital-dependent plateaus. (JMT)
It is known that treatment of mouse S49 thymic lymphoma cells with N-acetoxy-2-acetylamino-fluorene (NA-AAF) or ethylnitrosourea (ENU) activate two quiescent genes, metallothionein I (MT-I) and metallothionein II (MT-II) (Annual Summary Report, 12/1/86). ...
Acetyl-aminofluorene (AAF) modified plasmid pSV sub 2 CAT is being studied to learn how the adducts influence expression of chloramphenicol acetyltransferase (CAT) genes. phi X-174 RF DNA exhibits specific base sequence abnormalities induced by the format...
Our previous studies on acetylaminofluorene (AAF) modified DNA demonstrated three kinds of structural changes in DNA of defined base sequence. For example, adduct formation by N-Aco-AAF was found at each guanine. We studied the interaction of IgG specific...
Exposure to chemical carcinogens can often be identified by detection of DNA adduct lesions. Primary cultures of isolated rat and human hepatocytes were exposed to 2-acetyl-aminofluorene (AAF), 4-aminobiphenyl (ABP), or benzo(a)pyrene (BP). The isolated D...
Exposure to chemical carcinogens can often be identified by detection of DNA adduct lesions. rimary cultures of isolated rat and human hepatocytes were exposed to 2-acetyl-aminofluorene (AAF), 4-aminobiphenyl (ABP), or benzo[a]pyrene (BP). he isolated DNA 32P-postlabeling assay. ...
Minimized conformational potential-energy calculations have been performed for the major adduct of N-2-acetylaminofluorene (AAF) and aminofluorene (AF) with dCpdG. The DNA backbone conformations that produce base displacement, about which no information w...
Three kinds of structural disturbances were found in an 88 base pair (bp) fragment of thetaX-174 DNA after exposure to N-acetoxy-N-2-acetylaminofluorene (N-Aco-AAF). Frequent strand scissions at two specific guanine sites on the 5' /sup 32/P-end-labeled fragment were identified by base sequence analysis. Scissions at these two sites were induced at neutral pH and they ...
Previously we have demonstrated that several xenobiotics can induce multidrug (mdr) gene expression in cultures of primary isolated hepatocytes. One of the best of these xenobiotic inducers in rat hepatocytes is 2-acetylaminofluorene (2-AAF), which induces mdr expression by an enhancement of mdr gene transcription. In all species studied to date, AAF is extensively and ...
Neutral sucrose gradients of supercoiled DNA (PHIX-174 RF1) were used to measure the in vitro production of strand breaks by the carcinogen, N-acetoxy-2- acetylaminofluorene (AcO-AAF). Treatment with AcO-AAF in 10 percent dimethyl sulfoxide did not directly yield strand breaks. Breaks in relatively low yield appeared after alkali treatment (pH 13, 60 min) of the RF I ...
Repair kinetics after saturating doses of ultraviolet radiation (uv), N-acetoxy-2-acetylaminofluorene (AAAF), and combinations of both agents were studied in human fibroblasts proficient and deficient in excision repair, and in Chinese hamster cells (V-79) deficient in excision repair. Three techniques were used: unscheduled DNA synthesis, photolysis of DNA repaired in the ...
The activity of an endonuclease(s) acting on double-stranded, ultraviolet-irradiated, and 2-acetylaminofluorene-bound DNA but not on double-stranded undamaged DNA triples within two hr after partial hepatectomy. Although the activity drops between four and six hr after operation, it remains above levels measured in livers of nonhepatectomized rats until 36 hr after operation. ...
Studies in this laboratory first showed that the incidence of hepatic tumors induced by a brief exposure to dietary 2-acetylaminofluorene (AAF) is substantially increased if the AAF treatment is followed by prolonged phenobarbital feeding. Our subsequent experiments focused in part on an examination of the characteristics of the tumorigenic enhancement process in liver in an ...
A marked increase in the amount and relative proportion of fraction II of the smooth endoplasmic reticulum (SER II) and a concomitant decrease in the SER I fraction were observed in the liver of male Sprague-Dawley rats fed diets containing 0.05% (w/w) 2-acetylaminofluorene (AAF) for various lengths of time (3-18 weeks). The amount of rough endoplasmic reticulum (RER), which ...
In this study, acute and chronic responses of pancreatic hepatocytes induced in F-344 rats by copper depletion-repletion protocol to certain hepatocarcinogens were examined. Administration of a single dose of tannic acid (subcutaneous), aflatoxin B1 (gavage), or lasiocarpine (intraperitoneally) caused characteristic nucleolar segregation in parenchymal cells of liver as well as in pancreatic ...
The marine ciliate Parauronema acutum converted 2-aminofluorene and 2-acetylaminofluorene to compounds with mutagenic activity in the Ames Salmonella test. The ciliate, however, did not activate benzo (?)pyrene or benzanthracene or destroy the mutagenic properties of nitrosoguanidine. Homogenates, when substituted for the liver S-9 fraction in the Salmonella/microsome test, ...
The present study was designed to confirm the recent proposal that 2-nitrosofluorene (2-NOF) as well as N-hydroxy-2-aminofluorene (N-OH-AF) induce a redox-cycle in rat liver mitochondria as part of the chronic toxic effects of the carcinogen 2-acetylaminofluorene (2-AAF). The formation of O2.- was demonstrated in submitochondrial particles by the formation of adrenochrome with ...
The growth of preneoplastic nodules during the feeding of a carcinogenic 2-acetylaminofluorene (2-AAF) regimen is preceded by several alterations in the physiologic homeostasis. Many of these alterations can be considered adaptive responses to the drug exposure. One property of AAF could be identified that clearly distinguishes this complete rat liver carcinogen from at least ...
A Sal I-Hin dIII restriction fragment from Mycobacterium tuberculosis was found to hybridize specifically with genomic DNA from M. tuberculosis. Primers were designed from the sequence of this fragment and used to amplify uniquely M. tuberculosis-group DNA in a polymerase chain reaction. It is suggested that a combination of these primers and an acetylaminofluorene-labelled ...
A mouse hybrid hybridoma (tetradoma) was prepared by fusing hybridomas producing monoclonal antibody to acetyl-aminofluorene with hybridomas producing antibody against calf intestine alkaline phosphatase. The tetradoma line established secreted immunoglobulin manifesting parental and bispecific binding characteristics. Bispecific monoclonal antibody was purified and used for a ...
Chemicals that induce cancer at high doses in animal bioassays often fail to fit the traditional characterization of genotoxins. Many of these nongenotoxic compounds (such as sodium saccharin) have in common the property that they increase cell proliferation in the target organ. A biologically based, computerized description of carcinogenesis was used to show that the increase in cell ...
Mutagenic specificity of 2-acetylaminofluorene (AAF) has been established in mammalian cells and several strains of bacteria by using a shuttle plasmid vector containing a single N-(deoxyguanosin-8-yl)acetylaminofluorene (C8-dG-AAF) adduct. The nucleotide sequence of the gene conferring tetracycline resistance was modified by conservative codon replacement ...
In vitro DNA synthesis on a phi X174 template primed with a restriction fragment and catalyzed by the Escherichia coli DNA polymerase I large (Klenow) fragment (pol I) terminates at the nucleotide preceding a site that has been altered by ultraviolet irradiation or treatment with N-acetylaminofluorene. Termination on ultraviolet-irradiated templates is similar when synthesis ...
Coincubation of isolated, intact rat hepatocytes with Salmonella typhimurium tester strain TA 98 (Salmonella/hepatocyte system) has been employed to determine both bacterial mutagenicity and DNA damage in the hepatocytes following treatment with 2-acetylaminofluorene (AAF) and other AAF derivatives. In vivo pretreatment of rats with either 2,3,7,8,-tetrachlorodibenzo-p-dioxin ...
IS6100 is an insertion sequence of the IS3 family and it is present in multiple copies in the chromosome of Mycobacterium tuberculosis. Four to 15 copies are present in various strains of M. tuberculosis. In this study, the value of IS6110 as an epidemiological marker of tuberculosis was examined. Unrelated clinical strains from Greek patients presented, in restriction fragment length polymorphism ...
2-Nitrofluorene (NF), a model substance for nitrated polycyclic aromatic hydrocarbons, is present in exhaust from diesel- and petrol-driven vehicles, in exhaust from kerosene heaters, and in urban air and river sediments. Therefore the possible consequences of human exposure are important to elucidate. In the present study the initiating and promoting activity of NF was studied in a liver model ...
The hepatocyte primary culture (HPC)/DNA repair test was developed using hepatocytes isolated from male F-344 rats. A number of genetic polymorphisms have been shown to occur in inbred strains of rats, which may lead to variation in biotransformation of xenobiotics resulting in differences in susceptibility to genotoxins. The effect of the strain utilized as a source of hepatocytes was ...
All liver tumors induced in rats by acetylaminofluorene (AAF) or dimethylaminoazobenzene (DAB), but only one out of 29 tumors induced by ethionine, exhibited new isozymes of aldehyde dehydrogenase. These new isozymes, which differed from those of normal liver with regard to activity, pI, stability, cellular distribution, and coenzyme specificity, were not found in fetal or ...
A safety protocol implemented at the Los Alamos Scientific Laboratory for a project involving 14 chemical carcinogens is described. The carcinogens are: 4,4/sup 3/-methylenebis (2-chloroaniline); benzidine and salts; 3,3'-dichlorobenzidine and salts; ..beta..-naphthylamine; ..cap alpha..-naphthyalmine; bis(chloromethyl) ether; chloromethyl methyl ether; ..beta..-propiolactone; ...
The principal goal of this research has been the determination of the conformational changes produced in DNA by the covalent binding of a carcinogenic aromatic amine, and the correlation of these changes with the mutations and carcinogenic effects initiated by the same substances. To this end, we have devised new synthetic methods for the preparation of oligonucleotides modified by derivatives af ...
We have found that a wide variety of DNA-damaging agents and heat shock increase fos RNA to different extents in Chinese hamster ovary cells. These include the monofunctional alkylating agents methylmethane sulfonate and N-methyl-N'-nitro-N-nitrosoguanidine, the cross-linking agents cis-Pt(II) diamminedichloride and mechlorethamine HCl, the DNA base-damaging agents ...
The ionic complex between lysozyme and either Escherichia coli DNA or pBR322 DNA was not crosslinked by two systems capable of producing nanomolar amounts of hydroxyl radicals, the oxidation of xanthine by xanthine oxidase and the iron catalyzed oxidation of ascorbic acid. Nor did effective crosslinking occur with micromolar quantities of hydroxyl radicals raised by the addition of adenosine ...
A high-pressure liquid chromatography method was developed to separate 2-aminofluorene and several ring-hyroxylated metabolites. The acetylated derivatives of these compounds and N-hydroxy-2-acetylaminofluorene were also separated simultaneously. HPLC analyses were performed using a Dupont Zorbax C-8 HPLC column and a solvent mixture of 0.02 M acetic acid and isopropanol. ...
DNA replication is an asymmetric process involving concurrent DNA synthesis on leading and lagging strands. Leading strand synthesis proceeds concomitantly with fork opening, whereas synthesis of the lagging strand essentially takes place on a single-stranded template. The effect of this duality on DNA damage processing by the cellular replication machinery was tested using eukaryotic cell ...
Cells from different organ or animal species have shown diverse activities in activation and detoxification of chemical carcinogens. Based on the mutation assays, human hepatocytes were more effective than animal hepatocytes in detoxification of aromatic nitrogen compounds. The adduct formation was also different in human and rodent hepatocytes exposed to aminofluorene (AF) or ...
Epidemiological evidence suggests that the human population is exposed to environmental agents that increase the risk of cancer. The two-stage or initiation-promotion model of tumorigenesis raises the possibility that such environmental agents may comprise both carcinogens and substances that are not carcinogens themselves but instead enhance the tumorigenic effects of brief exposures to low ...
Beet Necrotic Yellow Vein Virus (BNYVV) was detected by enzyme-linked immunosorbent assay (ELISA) and RNA/DNA dot hybridization using either radiolabelled or non-radioactive probes. Dot hybridization specifically distinguished isolates that could not be distinguished by ELISA. The detection thresholds for ELISA, hybridization with non-radioactive probes and hybridization with radiolabelled probes ...
The plaque development of Herpes simplex virus type 1 (HSV) is slower for viruses treated with two anti-DNA agents: ultraviolet radiation (uv) or n-acetoxy-2-acetyl-aminofluorene. For HSV treated with three antimembrane agents - butylated hydroxytoluene, acridine plus near uv radiation, or ether - the plaque development time is the same as for untreated viruses. These ...
Unique N-acetyl-2-aminofluorene (AAF) or 2-aminofluorene (AF) adducts were introduced into the Xenopus borealis somatic 5S RNA gene between the intragenic control region and the transcription termination site. The effects of these bulky adducts on transcription were studied in a cell-free extract derived from Xenopus laevis oocytes. AAF and AF adducts inhibit transcription only when they are on ...
Zebrafish embryos have been shown to be a useful model for the detection of direct acting teratogens. This communication presents a protocol for a 3-day in vitro zebrafish embryo teratogenicity assay and describes results obtained for 10 proteratogens: 2-acetylaminofluorene, benzo[a]pyrene, aflatoxin B(1), carbamazepine, phenytoin, trimethadione, cyclophosphamide, ifosfamide, ...
Vanadium is an important regulator of cellular growth, differentiation, and cell death, and thus has received increasing attention to be an effective cancer chemopreventive agent. In the present study, attempts have been made to investigate the in vivo antineoplastic effect of this micronutrient at the 0.5 ppm dosage in drinking water, by monitoring hepatic nodulogenesis and hepatocellular ...
Excision repair of bulky adducts in alpha DNA of African green monkey cells has previously been shown to be deficient relative to that in the overall genome. We have found that u.v. irradiation of these cells results in the enhanced removal of both aflatoxin B1 (AFB1) and acetylaminofluorene (AAF) adducts from the alpha DNA sequences without affecting repair in the bulk of the ...
In the yeast Saccharomyces cerevisiae, DNA polymerase ? (Pol?) is required in a major lesion bypass pathway. To help understand the role of Pol? in lesion bypass, we have performed in vitro biochemical analyses of this polymerase in response to several DNA lesions. Purified yeast Pol? performed limited translesion synthesis opposite a template TT (6-4) photoproduct, incorporating A or T with ...
It is well established that genotoxic reactivity of chemical carcinogens or their metabolites is a critical event in the initiation of tumorigenesis. However, the underlying mechanisms of events following initiation are less well understood, and with respect to genotoxic liver carcinogenesis, it is largely unknown how the initiated cells progress to form preneoplastic hepatic foci. In the present ...
The anticancer efficacy of tocotrienol-rich fraction (TRF) was evaluated during diethylnitrosamine (DEN)/2-acetylaminofluorene (AAF)-induced hepatocarcinogenesis in male Sprague-Dawley rats. TRF treatment was carried out for 6 months, and was started 2 weeks before initiation phase of hepatocarcinogenesis. Morphological examination of the livers from DEN/AAF rats showed ...
Sulfation is a common final step in the biotransformation of xenobiotics and is traditionally associated with inactivation. However, the sulfate group is electron-withdrawing and may be cleaved off heterolytically in some molecules leading to electrophilic cations which may form adducts with DNA and other important cellular structures. Since endogenous sulfotransferases do not appear to be ...
The NarI restriction enzyme recognition site, G1G2CG3CC, has been identified as a hotspot for -2 frameshift mutations induced by N-2-acetylaminofluorene (AAF) on the basis of a forward mutation assay in plasmid pBR322 in the bacterium Escherichia coli. AAF binds primarily to the C-8 position of guanine residues, and the three guanines of the NarI site are similarly reactive. ...
Solanum nigrum L. (SN) is a widespread plant and is regarded as a common relish in the east and the south of Taiwan. Our previous study has found that SN water extract (SNWE) alleviated carbon tetrachloride-induced liver damage in rats. However, the effects of SNWE on chemical-induced hepatic injury and hepatocarcinogenesis remain unclear. Therefore, this study aims to investigate the effects of ...
Formation of site-specific DNA adducts allows the synthesis of chemically defined lesions that can be used for study of the functional consequences of these reactions. A reactive derivative, N-acetoxy-2-aminofluorene (N-Aco-AF), can be formed by enzymatic O-acetylation of the carcinogen, N-hydroxy-2-aminofluorene. Synthetic N-acetoxy-N-trifluoro-acetyl-2-aminofluorene (N-Aco-N-TFA-AF) has now been ...
2-Acetylaminofluorene (AAF), a potent rat liver carcinogen that binds covalently to the C-8 position of guanine residues in DNA, is an effective frameshift mutagen. The mutations are distributed nonrandomly, in that most are located at a few specific DNA sequences (i.e., mutation hot spots). Among these hot spots, the Nar I sequence (GGCGCC) is especially susceptible to the ...
Previous studies by this laboratory have indicated that expression of the multidrug resistance (mdr) gene can be increased in vivo by exposure to a variety of xenobiotics. Because of the nature of these compounds, it was proposed that mdr gene expression might, at least in part, be regulated by the arylhydrocarbon (Ah) receptor. In the present study, we used a primary hepatocyte culture model to ...
To investigate early cellular alterations in liver DNA during hepatocarcinogenesis, the authors have visualized replicating cells and analyzed their DNA adduct content in livers of rats continuously fed a carcinogenic level (0.02%) of 2-acetylaminofluorene for periods up to 4 weeks. One hour prior to sacrifice, cells undergoing DNA synthesis were pulse-labeled with the ...
The instability of the solubilized/purified form, the lack of catalytic activity of the stabilized, macrolide-complexed form, and the compromised catalytic activity of the decomplexed form of steroid-inducible cytochrome P450IIIA1 motivated further investigations of the substrate specificity of this isozyme. A major complementary goal was to identify reactions utilizable as sensitive, specific ...
Compounds like N-acetoxy-2-acetylaminofluorene (N-AcO-AAF) result from the in vivo reduction of nitrate derivatives of benzo(..cap alpha..)pyrene. The dose-response relationship for survival of cloning ability in human fibroblasts exposed to N-AcO-AAF is being investigated to obtain a better understanding of the carcinogenic potential of coal-related air pollutants. A model is ...
Minimized potential energy calculations have been employed to locate and evaluate energetically a number of different models for DNA modified at carbon-8 of guanine by acetylaminofluorene (AAF). Three different duplex nonamer sequences were investigated. In addition to syn guanine models which have some denaturation and a Z-DNA model, we have found two new types of structures ...
Chinese hamster ovary (CHO) cells were exposed to 2-acetylaminofluorene (2-AAF) and 2-aminofluorene (2-AF), and several of their N-oxidized metabolites in order to study the mechanisms by which arylamides and arylamines produce mutations in mammalian cells. The number of mutations induced at the hypoxanthine-guanine phosphoribosyl transferase locus by each compound was ...
The model carcinogen N-2-acetylaminofluorene covalently binds to the C8 position of guanine to form two adducts, the N-(2'-deoxyguanosine-8-yl)-aminofluorene (G-AF) and the N-2-(2'-deoxyguanosine-8-yl)-acetylaminofluorene (G-AAF). Although they are chemically closely related, their biological effects are strongly different and they are processed by ...
The livers of male F344 rats which were fed 0.02% 2-acetylaminofluorene (2-AAF) for two days or more had decreased binding of insulin and epidermal growth factor (EGF) to their hepatic receptors in microsomal and Golgi fractions. Hepatic receptors which were partially purified from carcinogen-fed rats by Triton X-100 solubilization and wheat germ agglutinin affinity column ...
Mutations induced in liver cells by the hepatocarcinogen 2-acetylaminofluorene (2-AAF) were characterized after i.p. administration on 4 consecutive days at 100 mg/kg per injection in male B6C3F1 Big Blue transgenic mice that harbored the Escherichia coli lacI reporter gene. Animals were sacrificed at 5, 10 or 60 weeks following the last injection, livers removed and DNA ...
The metabolism of various carcinogens and other chemicals by genetically regulated increases in cytochrome P/sub 1/-450 content was studied with the use of liver from 3-methylcholanthrene (MCA)-treated C57BL/6N and DBA/2N mice. (P/sub 1/-450 is defined as that form(s) of cytochrome that increases during polycyclic aromatic inducer treatment of the laboratory animal or cells in culture. Two forms ...
The rat mammary carcinogen, N-hydroxy-2-acetylaminofluorene (N-hydroxy-2-AAF), has been proposed to be metabolically activated by mammary cytosolic N,O-acetyltransferase to a DNA binding species. To test this hypothesis, adult female Sprague-Dawley derived CD rats were treated, i.p., with 4.0 mg/kg (ring-/sup 3/H)N-hydroxy-2-AAF. After 4 h, 1, 3, 14, and 28 days, the animals ...
With the publication of revised draft ICH guidelines (Draft ICH S2), there is scope and potential to establish a combined multi-end point in vivo assay to alleviate the need for multiple in vivo assays, thereby reducing time, cost and use of animals. Presented here are the results of an evaluation trial in which the bone-marrow and peripheral blood (via MicroFlow(�) flow cytometry) micronucleus ...
Certain enzymes of the mevalonate pathway have been investigated in persistent liver nodules induced in the rat by 2-acetylaminofluorene. In these nodules the dolichol level was increased 5-fold, the ubiquinone-9 content elevated 6-fold and the amount of cholesterol unchanged. Microsomal beta-hydroxy-beta-methylglutaryl-coenzyme A reductase activity was greatly increased ...
In previous experiments we observed that the short-term feeding of 2-acetylaminofluorene (AAF) at a low dietary concentration resulted in the late appearance of well-differentiated hepatic tumors at low incidence levels. When the AAF treatment was followed by the feeding of a phenobarbital-supplemented diet, the appearance of these tumors was accelerated, and their overall ...
The authors reported a marked loss of cytochrome P-450 in hepatic nuclear envelope (NE) but not in microsomes of male Sprague-Dawley rats fed a semipurified diet containing 0.05% w/w 2-acetylaminofluorene (AAF) for 3 weeks. This may reflect loss of NE capacity to detoxify AAF metabolites generated by microsomal P-450. They are now investigating if dietary effects such as ...
The dose-dependent and sex-related effects of 3 hepatocarcinogens were investigated by measuring the number and area of gamma-glutamyl transpeptidase (gamma-GT) positive foci appearing in the liver. For this, three different doses of 2-acetylaminofluorene (2-AAF), 3'-methyl-4-dimethylaminoazobenzene (3'-Me-DAB) and DL-ethionine (ethionine), respectively, were given to F344 ...
Five different dose levels of 2-acetylaminofluorene (2-AAF) were fed to weanling mice of 4 different genotypes from three unrelated F/sub 1/ hybrids for 13 wk to determine differences in susceptibility to induction of bladder hyperplasia. Differences in the prevalence of hyperplasia per se and in the average grade of hyperplasia were interpreted as indicating greater ...
Minimized conformational potential energy calculations were performed for dCpdG modified with the carcinogen 2-(acetylamino)fluorene (AAF). The major adduct, linked via a covalent bond between guanine C-8 and N-2 of AAF, was investigated. The 12 variable torsion angles and both deoxyribose puckers were independent flexible parameters in the energy minimizations. Three ...
Minimized conformational potential energy calculations were performed for dCpdG modified with the carcinogen 2-(acetylamino)fluorene (AAF). The major adduct, linked via a covalent bond between guanine C-8 and N-2 of AAP, was investigated. The 12 variable torsion angles and both dexoyribose puckers were independent flexible parameters in the energy minimizations. Three ...
Sixty-one xeroderma pigmentosum (XP) patients living in the Federal Republic of Germany were investigated. Clinical symptoms were correlated with DNA repair parameters measured in fibroblasts grown from skin biopsies. Classification according to the international complementation groups revealed that of the 61 patients 3 belonged to group A, 26 to group C, 16 to group D, 3 to group E, and 2 to ...
Dysregulated intracellular iron homeostasis has been found not only in rodent and human hepatocellular carcinomas, but also in several preneoplastic pathological states associated with hepatocarcinogenesis; however, the precise underlying mechanisms of metabolic iron disturbances in preneoplastic liver and the role of these disturbances remain unexplored. In the present study, using an in vivo ...
When hepatocyte regeneration is impaired, facultative stem cells and their descendants, also called oval cells, become activated and produce cell progeny that eventually differentiate. We have observed these cells in the rat liver after partial hepatectomy when the animals have been fed 2-acetylaminofluorene. Oval cells emerge from the portal areas and stain strongly with ...
Studies on structurally related aromatic amines with different carcinogenic properties have shown that 2-acetylaminofluorene (2-AAF) and 2-acetylaminophenanthrene (AAP) inhibit the binding of 2,3,7,8-tetrachlorodibenzo-p-dioxin to the Ah receptor in vitro. The apparent inhibitor constants (K{sub i}) are 2.3 {mu}M for 2-AAF and 2.7 {mu}M for AAP. In contrast, ...
Currently, the only way to identify nongenotoxic hepatocarcinogens is through long-term repeat dose studies such as the 2 year rodent carcinogenicity assay. Such assays are both time consuming and expensive and require large amounts of active pharmaceutical or chemical ingredients. Thus, the results of the 2 year assay are not known until very late in the discovery and development process for new ...
Bypass across DNA lesions by specialized polymerases is essential for maintenance of genomic stability. Human DNA polymerase ? (pol?) is a bypass polymerase of the Y family. Crystal structures of pol? suggest that Hoogsteen base pairing is employed to bypass minor groove DNA lesions, placing them on the spacious major groove side of the enzyme. Primer extension studies have shown that pol? is also ...
Primer extension studies have shown that the Y-family DNA polymerase IV (Dpo4) from Sulfolobus solfataricus P2 can preferentially insert C opposite N-(deoxyguanosin-8-yl)-2-acetylaminofluorene (AAF-dG) [F. Boudsocq, S. Iwai, F. Hanaoka and R. Woodgate (2001) Nucleic Acids Res., 29, 4607�4616]. Our goal is to elucidate on a structural level how AAF-dG can be harbored in the ...
The usefulness of the ID32 Staph System and a method based on rRNA gene restriction site polymorphism was evaluated by the study of 42 staphylococcal clinical isolates phenotypically difficult to identify. The ID32 Staph micromethod and the genomic method are adapted for recognition of 27 and 31 staphylococcal taxa, respectively. The genomic method is based on a Dice analysis of the hybridization ...
The use of antibodies to detect chemical carcinogen-induced DNA damage involves quantitative determination and morphological localization utilizing antisera specific for carcinogen-DNA adducts. In recent years a large number of polyclonal and monoclonal antisera have been produced against individual adducts, and modified DNAs with addition products varying in structure from ethyl and methyl groups ...
Irradiation of dominant marker DNA with UV light (150 to 1,000 J/m2) was found to stimulate the transformation of human cells by this marker from two- to more than fourfold. This phenomenon is also displayed by xeroderma pigmentosum cells (complementation groups A and F), which are deficient in the excision repair of UV-induced pyrimidine dimers in the DNA. Also, exposure to UV of the transfected ...
Pretreatment of 3T6 murine cells with the carcinogen UV radiation or N-acetoxy-N-acetylaminofluorene increased the number of methotrexate-resistant colonies. This carcinogen-induced enhancement was seen only at low toxicities. The enhancement was transient and was observed at its maximum when cells were subjected to methotrexate selection 12 to 24 h after treatment. The ...
Experiments were conducted to study the transplacental and translactational passage and distribution of radiolabeled N-OH-2-AAF in the BALB/c mouse. The radiolabeled N-OH-2-AAF radily crossed the placenta to the fetuses when the compound was administered by oral gavage to pregnant BALB/c mice during late gestation. The radioactivity from the (/sup 3/H)-N-OH-2-AAF was detected in the fetuses as ...
Many aquatic organisms thrive and reproduce in polluted waters. This fact indicates that they are well equipped with a defense system(s) against several toxic xenobiotics simultaneously because water pollution is typically caused by a mixture of a number of pollutants. We have found that the biochemical mechanism underlying such multixenobiotic' resistance in freshwater and marine ...
Liverbeads, cryopreserved hepatocytes entrapped within an alginate matrix, were examined for their relevance in the comet assay. It was estimated by their capacity to activate the indirectly acting mutagens, cyclophosphamide (CP), benzo[a]pyrene (BP), dimethylbenzanthracene (DMBA) and 2-acetylaminofluorene (2-AAF), into DNA reactive metabolites. The comet assay performed in ...
Static and dynamic molecular views of a short segment of DNA modified by the tumorigenic aromatic amine 2-acetylaminofluorene (AAF) have been realized by a combination of high resolution nuclear magnetic resonance (NMR) studies in solution and molecular mechanics and molecular dynamics simulations carried out on supercomputers. Thus, the effect of AAF on the structure of the ...
It has been demonstrated in several model systems that tumors arise in a multistage process. Carcinogenic aromatic amines are complete carcinogens, which usually produce tumors in typical target tissues without any additional treatment. The tissue specificity, however, cannot readily be explained by genotoxic effects, and the role of secondary effects is not well understood. Promotional pressure ...
Thirty-one strains of Pseudomonas aeruginosa, isolated from water springs, clinical isolates (some of which were from cystic fibrosis (CF) patients), and two type cultures, were characterized by ribotyping. After restriction of chromosomal DNA of the different isolates with EcoRI and hybridization of Southern transfer blots with 2-acetylaminofluorene labelled Escherichia coli ...
Liver fatty acid binding protein (L-FABP) is the principal target protein of the hepatic carcinogen N-(2-fluorenyl)acetamide (2-acetylaminofluorene) in rat liver. In addition, the cyclopentenone prostaglandins (PG), PGA, PGJ{sub 2}, and {Delta}{sup 12}-PGJ{sub 2}, inhibit the growth of many cell types in vitro. This report describes the preferential binding of the growth ...
Lymphocytes from 38 individuals occupationally exposed to styrene concentrations in workroom air of 1 p.p.m. to 40 p.p.m. were examined for any genotoxic effects using unscheduled DNA synthesis (UDS) as the indicator of DNA damage. The mean level of N-acetoxy-2-acetylaminofluorene (NA-AAF) induced UDS was significantly increases (p less than 0.001) for the styrene exposed ...
Our objective, has been to elucidate on a molecular level, at atomic resolution, the structures of DNAs modified by 2-aminofluorene and its N-acetyl derivative, 2-acetylaminofluorene (AAF). The underlying hypothesis is that DNA replicates with reduced fidelity when its normal right-handed B-structure is altered, and one result is a higher mutation rate. This change in ...
Methylation of deoxycytidine incorporated by DNA excision-repair was studied in human diploid fibroblasts following damage with ultraviolet radiation, N-methyl-N-nitrosourea, or N-acetoxy-2-acetylaminofluorene. In confluent, nondividing cells, methylation in repair patches induced by all three agents is slow and incomplete. Whereas after DNA replication in logarithmic-phase ...
5-Methyl-2'-deoxycytidine (m5dC) levels were measured in DNA from three types of cultured cells following treatment with u.v. radiation and two chemical carcinogens, N-methyl-N-nitrosourea (MNU) and N-acetoxy-2-acetylaminofluorene (NA-AAF). Control values for m5dC in Raji cells (a human lymphoblastoid cell line), S49 cells (a mouse thymic lymphoma cell line) and human ...
Heterocyclic aromatic amines produce bulky C8 guanine lesions in vivo, which interfere and disrupt DNA and RNA synthesis. These lesions are consequently strong replication blocks. In addition bulky adducts give rise to point and frameshift mutations. The translesion synthesis (TLS) DNA polymerase ? is able to bypass slowly C8 bulky adduct lesions such as the widely studied 2-aminofluorene-dG and ...
The metabolism of 2-acetylaminofluorene (AAF) to its six oxidative metabolites has been used to study cytochrome P-450 monooxygenase activity in two rat hepatoma cell lines, McA-RH7777 and Reuber H4-II-E. McA-RH7777 cells exhibited considerably higher basal activities than H4-II-E cells for all metabolic pathways studied. Phenobarbital induced AAF metabolite formation in ...
During incomplete combustion of organic matter, nitro-polycyclic aromatic hydrocarbons (nitro-PAHs), are formed in a reaction that is catalyzed by a low pH. 2-Nitrofluorene (NF), a marker for nitro-PAHs, is metabolized in vivo by two different routes. After inhalation, potent mutagenic metabolites, hydroxylated nitrofluorenes (OH-NFs), are formed. The metabolites are distributed by systemic ...
Numerous enzymatic and chemical methods are now available for the preparation of non-radioactive nucleic acid probes. Labels, such as enzymes, fluorophores, lumiphores can be attached to the nucleic acid probe either by covalent bonds (direct labelling) or by biospecific recognition after hybridization (indirect labelling). The principle of the latter method is based on the use of a ...
Bromodeoxyuridine labeling of DNA, binuclearity counting, and flow cytometric analysis of isolated hepatocytes and hepatocyte nuclei has been used to assess heptocellular growth patterns related to liver carcinogenesis. Three growth patterns can be distinguished. Mononucleating growth is observed during liver regeneration and after treatment with the tumor promoter ...
The p53 gene is frequently mutated in cancers and it is vital for cell cycle control, homeostasis and carcinogenesis. We describe a novel p53 mutational spectrum, different to those generally observed in human and murine tumors. Our study shows a high prevalence of nonsense mutations in the p53 N terminus of 2-acetylaminofluorene (2-AAF)-induced urinary bladder tumors. These ...
The multidrug resistance-associated protein (MRP) subfamily transporters associated with anticancer drug efflux are attributed to the multidrug-resistance of cancer cells. The genomic organization of human multidrug resistance-associated protein 7 (MRP7) was identified. The human MRP7 gene, consisting of 22 exons and 21 introns, greatly differs from other members of the human MRP subfamily. A ...
Regenerating gene (Reg) I has been identified as a regenerative/proliferative factor for pancreatic islet cells. We examined Reg I expression in the regenerating liver of a rat model that had been administered 2-acetylaminofluorene and treated with 70% partial hepatectomy (2-AAF/PH model), where hepatocyte and cholangiocyte proliferation was suppressed and the hepatic stem ...
Male Fischer F344 rats (180-220 g) were fed either a basal diet, a diet supplemented with 2-acetylaminofluorene (AAF) 0.02% (w/w) for up to 3 months or dietary tumor promoters. Normal or AAF-altered hepatic microsomes were compared with respect to drug-induced lipid perioxidation. A three-fold decrease was found in the ability of adriamycin to induce lipid perioxidation on ...
The replication of UV-damaged Simian virus 40 (SV40) in carcinogen-treated monkey cells has been studied to elucidate the mechanism of carcinogen-enhanced reactivation. Carcinogen enhanced reactivation is the observed increase in UV-irradiated virus survival in host cells treated with low doses of carcinogen compared to UV-irradiated virus survival in untreated hosts. Carcinogen treatment of ...
Autoxidized linoleic acid (AL) having 800 meq/kg of peroxide value and 1,700 meq/kg of carbonyl value was given in repeated oral doses at a daily dose of 0 (control)--7.5 ml/kg to male Wistar rats for 5 successive days. The effect of increasing AL dose on the drug-metabolizing system was investigated in rat liver microsomes and S-9 fractions. All the rats of a daily dose of 5.0-7.5 ml/kg died ...
Nucleic acid sequences can be localized on chromosomes in the electron microscope after hybridization with a biotinylated DNA probe followed by detection with a primary antibiotin antibody and a secondary antibody coupled to colloidal gold. Hybridization probes can also be labelled with alternative ligands such as N-acetoxy-2-acetylaminofluorene (AAF), Dinitrophenyl-dUTP and ...
A model is presented that correlates the survival of cells in tissue culture exposed to toxic agents with the rate of excision of residues bound to DNA. Under the assumptions of the model, data on the survival of normal human fibroblasts (NF) and fibroblasts from xeroderma pigmentosum (XP) patients in complementation groups A, C and E (XPA, XPC and XPE) after exposure to ...
Many animal models for organ specific neoplasia have been developed and used to study the pathogenesis of cancer. Morphologic studies have usually concentrated on the response of target cells, whereas biochemical investigations have usually employed whole organ homogenates. Since hepatocytes comprise nearly 90% of the liver's mass and 70-80% of its DNA, alterations in DNA replication, covalent ...
18 Carcinogens, including aflatoxin B1, benzo(a)pyrene, acetylaminofluorene, benzidine, and dimethylamino-trans-stilbene, are shown to be activated by liver homogenates to form potent frameshift mutagens. We believe that these carcinogens have in common a ring system sufficiently planar for a stacking interaction with DNA base pairs and a part of the ...
Our previous studies on acetylaminofluorene (AAF) modified DNA demonstrated three kinds of structural changes in DNA of defined base sequence. For example, adduct formation by N-Aco-AAF was found at each guanine. We studied the interaction of IgG specific for AAF guanosine in an in vitro system using AAF modified phi X-174 rf DNA. We had expected to find protection against ...
An in vivo/in vitro DNA repair assay has been developed to quantitate chemically induced unscheduled DNA synthesis (UDS) in rat spermatocytes utilizing autoradiography. Male Fischer-344 rats were treated by i.p. injection or gavage with a variety of genotoxic agents dissolved in dimethyl sulfoxide, corn oil, or water. At selected times after treatment, spermatocytes were isolated by trypsin ...
Rodent post-implantation whole embryo culture (WEC) is a validated and widely used method in both mechanistic studies and as a screening test for developmental toxicants. Since metabolism is lacking in the WEC because of the developmental stage of the embryo, pro-teratogenic compounds are not detected. We investigated the inclusion of an in vitro metabolizing system as a pre-incubation step in the ...
The intralaboratory reproducibility of a DNA virus (SA7) transformation enhancement assay was investigated using nine carcinogenic and noncarcinogenic compounds representing a variety of chemical classes. By the use of standardized procedures designed to limit assay variables, replicate assay data were collected in two independent laboratories and analyzed for concurrence. The carcinogens, ...
Liquid chromatography-mass spectrometry (LC-MS) techniques are ideally suited to the investigation of DNA adduction. Most current experiments focus on the quantification of monomeric DNA adducts, or the reaction of synthetic oligonucleotides with a specific carcinogen. The methodology presented herein allows for examination of the sequence context of an adducted segment by the enzymatic digestion ...
We have examined the ability of human cell extracts to repair the most frequent DNA adduct caused by the cancer chemotherapeutic agent cis-diamminedichloroplatinum(II). A circular DNA duplex with an intrastrand d(GpG) crosslink positioned at a specific site was synthesized. Human cell extracts were unable to induce repair synthesis in a 29-base-pair region encompassing the adduct or in adjacent ...
Excision repair can be measured by using benzoylated naphthoylated DEAE cellulose (BND cellulose) to filter out DNA formed by replicative synthesis. A rapid batch method that permits analysis of many samples has been developed. Repair can be measured at growing points and in the bulk of the DNA. Using this technology, we have shown that the mutagen methyl nitronitrosoguanidine induces increased ...
The alkaline treatment of Guo, dGuo, dGMP and denatured DNA modified by N-acetoxyacetylaminofluorene (N-AcO-AAF) was performed in 0.1 M NaOH at 40 degrees C. The kinetics of the reaction were followed by ultraviolet absorption and by chromatographic methods and were found different for the four products under study. Circular dichroism spectra show differences in the environment of ...
The marine ciliate Parauronema acutum converted 2-aminofluorene and 2-acetylaminofluorene to compounds with mutagenic activity in the Ames Salmonella test. The ciliate, however, did not activate benzo(..cap alpha..)pyrene or benzanthracene or destroy the mutagenic properties of nitrosoguanidine. Phenobarbitol did not induce or increase the amount of activating activity. The ...
Our previous studies have shown that vanadium, a dietary micronutrient, has an inhibitory effect against experimentally induced rat hepatocarcinogenesis. In this study, we evaluated the role of vanadium on some potential protein expression markers of carcinogenesis, such as metallothionein (MT), an intracellular metal-binding protein linked with cell proliferation and apoptosis, Ki-67 nuclear ...
Aromatische Amine und Amide (aAA) sind aufgrund ihrer starken Verbreitung in der menschlichen Umwelt und ihres kanzerogenen Potenzials von groer toxikologischer Bedeutung. Die Kanzerogenit�t der aAA wird durch die Mutagenit�t hochreaktiver Stoffwechselprodukte vermittelt, die in zwei sequenziellen katalytischen Reaktionen entstehen. Die erste ist meistens eine N-Hydroxylierung, die oft durch ...
The major reaction products of the carcinogenic electrophile N-benzoyloxy-N-methyl-4-aminoazobenzene with guanosine or deoxyguanosine were characterized as N-(guanosin-8-yl)- and N-(DEOXYGUANOSIN-8-YL)-N-methyl-4-aminoazobenzene from the following chemical, radiochemical, and spectroscopic studies: (a) the presence of equimolar amounts of both N-methyl-4-aminoazobenzene (MAB) and guanosine or ...
Some compounds have structural isomers of which one is apparently carcinogenic, and the other not. Because of the similarity of their chemical structures, comparisons of their effects can allow gene expression elicited in response to the basic skeletons of the isomers to be disregarded. We compared the gene expression profiles of male Fischer 344 rats administered by daily oral gavage up to 28 ...
The role of protein kinase C and protein phosphatases was examined in the control of mutagenic metabolites of aromatic amines. Various metabolic activating systems derived from rat liver were treated with: 12-O-tetradecanoylphorbol-13-acetate (TPA), a protein kinase C modulator; okadaic acid (OA), a potent inhibitor of serine/threonine protein phosphatases (PP1 and PP2A); and ortho-vanadate (OV), ...
To date the molecular signals regulating activation, proliferation, and differentiation of hepatic oval cells are not fully understood. The Wnt family is essential in hepatic embryogenesis and implicated in hepatic carcinogenesis. This study elucidates novel findings implicating Wnt1 in directing oval cell differentiation during the rat 2-acetylaminofluorene (2AAF) and ? ...
Selenium is an essential micronutrient mineral found mainly in soils and has been shown to prevent certain cancers in humans and animals. However, the dose and effects of selenium on liver cancer are controversial. The aim of this study was to investigate the effects of sodium selenite (4 mg/kg in drinking water) on chemically induced hepatocarcinogenesis in rats. Hepatocarcinogenesis was induced ...
Rat liver NOH-AAf sulfotransferase activity is mediated by AST IV and causes the bioactivation of NOH-AAF to a highly reactive, mutagenic sulfuric acid ester form which putatively has a role in inducing liver cancer. Unexpectedly, AAF has been found to decrease liver NOH-AAF sulfotransferase activity in dietary protocols used to induce hepatocarcinogenesis. The authors have thus examined ...
In eukaryotic cells, the Rad6/Rad18-dependent monoubiquitination of the proliferating cell nuclear antigen (PCNA) plays an essential role in the switching between replication and translesion DNA synthesis (TLS). The DNA polymerase Pol? binds to PCNA via a consensus C-terminal PCNA-interacting protein (PIP) motif. It also specifically interacts with monoubiquitinated PCNA thanks to a recently ...
Nitrated polycyclic aromatic hydrocarbons (nitro-PAHs) are formed during incomplete combustion. Sources include emissions from vehicles (mainly diesel vehicles), heating, smoking, certain types of food processing, and incomplete combustion in general. Nitro-PAHs are direct-acting mutagens, and a number of them have been shown to be carcinogens. 2-Nitrofluorene (NF) represents a model substance for ...
The conformation and dynamics of the dinucleotide d-CpG modified at the C(8) position of the guanine ring by the carcinogen 2-(acetylamino)fluorene has been investigated by high-field /sup 1/H NMR spectroscopy. A two-state analysis of chemical shift data has enabled estimation of the extent of intramolecular stacking in aqueous solution as a function of temperature. The ...
Biochemical measurements in the sentinel clam Chamaelea gallina have been used as biomarkers of marine pollution. In this study, S9, cytosolic fractions (CF), and microsomal fractions (MF) prepared from unexposed clams and clams exposed to model pollutants were used to activate 2-aminoanthracene (2-AA) and 2-acetylaminofluorene (AAF) to mutagens in Salmonella typhimurium ...
N-Acetoxyarylamines are reactive metabolites that are implicated in the initiation of the carcinogenic process by some N-substituted aryl compounds. The objective of this study was to explore the relationship between the production of these reactive species and N-acetylation (NAT), a reaction previously demonstrated to be polymorphic in the human. Human liver and urinary bladder mucosa samples ...
Hepatocytes in normal rat liver were found previously to contain a cytoplasmic 14,000-dalton polypeptide (p14) that is associated with mitosis and is the principal early covalent target of activated metabolites of the carcinogen N-2-fluorenylacetamide (2-acetylaminofluorene). The level of immunohistochemically detected p14 was low when growth activity of hepatocytes was low, ...
The use of unicellular algae in ecotoxicity testing is well established, particularly regarding whole-organism and population-level end points such as lethality and population growth. Conflicting information exists, however, on the potential for genetic toxicity to be incorporated into the safety studies in this test organism. In the present study, DNA strand breaks (Comet assay) and ...
Toxicogenomic approaches have been applied to chemical-induced heptocarcinogenesis rodent models for the identification of biomarkers of early-stage hepatocarcinogenesis and to help clarify the underlying carcinogenic mechanisms in the liver. In this study, we used toxiciogenomic methods to identify candidate biomarker genes associated with hepatocarcinogenesis in rasH2 mice. Blood chemical, ...
Gene activation can be studied at several levels: transcription (mRNA), translation (proteins), or phenotypical alterations (functional activity or morphology). These levels can be studied in situ or biochemically by the use of specific probes for normal or altered DNA, mRNA, or proteins. Immunological probes are potent tools for studies of alterations induced by xenobiotics in target organs. When ...
Folic acid (FA) supplementation during carcinogenesis is controversial. Considering the impact of liver cancer as a public health problem and mandatory FA fortification in several countries, the role of FA supplementation in hepatocarcinogenesis should be elucidated. We evaluated FA supplementation during early hepatocarcinogenesis. Rats received daily 0.08 mg (FA8 group) or 0.16 mg (FA16 group) ...
Selection for mutants that are sensitive to chemical mutagens was conducted with the aid of stocks bearing translocations between the two major autosomes of Drosophila melanogaster. A mutant linked to the second chromosome has been designated mus (2) 201 /sup D1/. Larvae homozygous for this mutation are hypersensitive to methyl methanesulfonate, nitrogen mustard and ...
Background/AimsOval cells (OCs), putative hepatic stem cells, may give rise to liver cancers. We developed a carcinogenesis regimen, based upon induction of OC proliferation prior to carcinogen exposure. In our model, rats subjected to 2-acetylaminofluorene/partial-hepatectomy followed by aflatoxin injection (APA regimen) developed well-differentiated ...
In an attempt to elucidate the relationship between DNA adduct formation and tumorigenesis, DNA adducts were measured in the livers and bladders of mice during chronic exposure to several different doses of 2-acetylaminofluorene (2-AAF) and 4-aminobiphenyl (4-ABP). Continuous oral administration of these compounds for 4 weeks produced an increase in DNA adduct formation during ...
The aromatic amines 2-aminofluorene (2AF), 2-acetylaminofluorene, and 2-aminoanthracene, and the heterocyclic amines 2-amino-3-methylimidazo[4,5-f]quinoline (IQ), 2-amino-3,4-dimethylimidazo[4,5-f]quinoline, and 3-amino-1-methyl-SH-pyrido[4,3-b]indole (Trp-P-2) were activated by rat liver cytosolic fractions to form mutagenic metabolites in Salmonella typhimurium strains TA98, ...
The xylidide 2,6-dimethylaniline (2,6-DMA) has produced carcinomas and papillary adenomas in the nasal cavity of rats at high dietary doses (3000 ppm) in a 2-yr bioassay. The objective of the present study was to measure the covalent binding of 2,6-DMA to DNA of rat ethmoid turbinate tissues and, for comparison, to DNA of rat liver. The potent hepatocarcinogen ...
Previous studies have demonstrated marked differences in the capacity of hepatocytes from rats or hamsters to mediate the metabolic activation of chemical carcinogens to genotoxic (i.e., mutagenic) products. Thus far, very few investigations of species differences in DNA repair have been performed. Therefore, a comparison of the relative extent of DNA repair elicited by various genotoxic chemicals ...
A biosurvey in the Danish metal industry measured the genotoxic exposure from stainless steel welding. The study comprised measurements of chromosomal aberrations (CA), sister-chromatid exchanges (SCE), unscheduled DNA synthesis (UDS) in peripheral lymphocytes and serum immunoglobulin G. Environmental monitoring of welding fumes and selected metal oxides, biomonitoring of chromium and nickel in ...
