Search Results
Results 251 - 300 of 712
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Higashimoto M - - 1998
It has been shown that the mutagenicity of 1-methyl-1,2,3,4-tetrahydro-beta-carboline-3-carboxylic acid (MTCCA), a mutagen precursor in soy sauce treated with nitrite, was strongly increased when it was treated with nitrite in the presence of alcohols. We found that the mutagenicity of MTCCA treated with 50 mM nitrite at pH 3, 37 ...
McCarthy MD - - 1998
Next to N2 gas, the largest pool of reduced nitrogen in the ocean resides in the enormous reservoir of dissolved organic nitrogen (DON). The chemical identity of most of this material, and the mechanisms by which it is cycled, remain fundamental questions in contemporary oceanography. Amino acid enantiomeric ratios in ...
Miyazawa M - - 1998
The methanol extract from Machilus thunbergii showed a suppressive effect on umu gene expression of the SOS response in Salmonella typhimurium TA1535/pSK1002 against the mutagen, 3-amino-1,4-dimethyl-5H-pyrido[4,3-b]indole (Trp-P-1), which requires liver metabolizing enzymes. The methanol extract from M. thunbergii was successively re-extracted with chloroform, butanol and water. A suppressive compound in ...
Moreira MT - - 1998
Bjerkandera sp. strain BOS55 is a white rot fungus that can bleach EDTA-extracted eucalyptus oxygen-delignified kraft pulp (OKP) without any requirement for manganese. Under manganese-free conditions, additions of simple physiological organic acids (e.g., glycolate, glyoxylate, oxalate, and others) at 1 to 5 mM stimulated brightness gains and pulp delignification two- ...
Jolivette L J - - 1998
2-Chloro-4-(methylthio)butanoic acid (1) is a direct-acting mutagen and suspected gastric carcinogen isolated from fish preserved with salt and nitrite. The reactive intermediates formed from acid 1 that may be associated with its mutagenicity have not been identified. A candidate reactive intermediate is proposed in this work. 1-Methyl-2-thietaniumcarboxylic acid may result ...
Oguri A - - 1998
It is important to search for effective antioxidants to suppress formation of mutagenic and carcinogenic heterocyclic amines (HCAs), like 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MeIQx) and 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP), because these HCAs are considered to be probable human carcinogens. The effects of various food-derived antioxidants on MeIQx formation were examined by their addition (0.2 mmol ...
Surh Y J - - 1998
Although sulfo-conjugation, in general, has been regarded as a detoxification process in the xenobiotic metabolism, there is a substantial body of data supporting that the same reaction can also lead to activation of certain types of chemical carcinogens and mutagens. Examples include some aromatic amines and amides, alkenylbenzenes, methyl-substituted polyaromatic ...
Lankaputhra W E - - 1998
Antimutagenic activities of live and killed cells of 6 strains of Lactobacillus acidophilus and 9 strains of bifidobacteria and of organic acids usually produced by these probiotic bacteria were determined using 8 potent chemical mutagens and promutagens. The mutagens and promutagens used were N-methyl, N'-nitro, N-nitrosoguanidine; 2-nitroflourene; 4-nitro-O-phenylenediamine; 4-nitroquinoline-N-oxide; Aflatoxin-B; ...
Shibuya N - - 1997
Mutagenicity and co-mutagenicity of glyco- and tauro-deoxycholic acids (GDCA and TDCA), which are abundant in human bile, were examined by the Ames test. The two chemicals were not mutagenic for themselves to Salmonella typhimurium TA98 and TA100, with and without S9 mix. They enhanced, however, the mutagenic activities of the ...
Pacheco M - - 1997
The purpose of this research is the study of total ethoxyresorufin O-deethylase (EROD) activity and erythrocytic nuclear abnormalities (NA) induction by polycyclic aromatic hydrocarbons (PAHs) and resin acids (RAs) on the juvenile eel Anguilla anguilla L. Juvenile eels were exposed, during 3 days, to the same molar concentration range (0, ...
Filius JD - - 1997
The adsorption of lactate, oxalate, malonate, phthalate, and citrate has been determined experimentally as a function of concentration, pH, and ionic strength. The data have been described with the CD-MUSIC model of Hiemstra and Van Riemsdijk [J. Colloid Interface Sci. 179, 488-508 (1996)] which allows a distribution of charge of ...
Scannell A G - - 1997
The effect of replacing sulphur dioxide with organic acids and nisin to reduce the microbial counts in fresh pork sausage was examined. The potential of sodium citrate or sodium lactate, used singly or in combination with nisin, was also assessed in sausage inoculated with Staphylococcus aureus MMPR 3 and Salmonella ...
Foltínová P - - 1997
The unicellular flagellate Euglena gracilis was used in order to assess the inhibition of N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) and N-methyl-N-nitrosourea (MNU) mutagenicities, which induce white mutants due to the irreversible loss of chloroplasts. All tested compounds, including o-aminobenzoic acid and p-aminobenzoic acid, salicylic acid, acetylsalicylic acid, sodium salicylate and p-aminosalicylic acid, were ...
Giller S - - 1997
Three short-term assays (SOS chromotest, Ames fluctuation test and newt micronucleus test) were performed to detect the genotoxic activity of organohalides, compounds likely to be found in chlorinated and/or ozonated drinking water: monochloro-, dichloro- and trichloroacetic acids and monobromo-, dibromo- and tribromoacetic acids. With the SOS chromotest, only three of ...
ZoƂadek T - - 1997
The yeast Saccharomyces cerevisiae was used as a model eukaryotic organism to study the uptake of diamino acid derivatives of porphyrins and their phototoxicity with particular emphasis on possible mutagenic effects. The water-soluble hematoporphyrin derivatives diarginate (HpD[Arg]2) and 1-arginin di(N-amino acid)-protoporphyrinate used in this study are effective photosensitizers in tumor ...
Odunola O A - - 1997
The genotoxic potentials of boric acid in Escherichia coli PQ37 was assessed along in the presence of aflatoxin B1 using SOS chromotest. Boric acid induced beta-galactosidase synthesis on the tester bacteria both on the presence and absence of S9 activation mixture. Therefore, the inorganic acid may not require metabolic activation ...
Ashby J - - 1997
Earlier reports that benzoic acid is uterotrophic to the rat and mouse and that clofibrate is uterotrophic to the rat have not been confirmed. The studies reported here involved the use of a range of test protocols and dose levels, including the protocols/dose levels used by the original investigators. In ...
Wu X - - 1997
Trigonelline and amino acids are natural components in green coffee beans. Model systems mimicking coffee roasting were used to produce heated samples of trigonelline, amino acids and glucose. Trigonelline and amino acids were heated separately or in combinations for 20 min at 250 degrees C. The results of bacteria mutation ...
King T M - - 1997
Mutagen sensitivity, as measured by an in vitro assay, has been described as a risk factor for the development of several tobacco-related epithelial cancers. In vitro studies have indicated that sensitivity to the clastogenic effects of bleomycin on chromosomes was reduced with the introduction of ascorbic acid in a dose-dependent ...
Barrington J W - - 1997
Nitrosamines are carcinogenic substances found in cigarette smoke, and it is known that female smokers have an increased risk of cervical carcinoma and premalignant change. Nitrosamines may also be formed due to the combination of amines and nitrites in an acidic medium. This study has shown a statistically significant association ...
Swenberg J A - - 1997
Occupational exposure to inorganic acid mists containing sulfuric acid has been associated with increased laryngeal cancer. The primary objective of this review was to compile the literature regarding chronic toxicity and carcinogenicity of inorganic acid mists in laboratory animals. Several chronic toxicity studies had exposures of 1 year or longer. ...
Bieler C A - - 1997
Recently, we reported that aristolochic acid (AA) a naturally occurring nephrotoxin and carcinogen is implicated in a unique type of renal fibrosis, designated Chinese herbs nephropathy (CHN). Indeed, we identified the principal aristolochic acid-DNA adduct in the kidney of five such patients. We now extend these observations and demonstrate the ...
Apostolides Z - - 1997
Aqueous solutions of gallic acid, methyl gallate, catechins, theaflavins and tannic acid were tested for inhibition of the mutagenicity of PhIP in the Salmonella typhimurium TA98 assay with an S9 fraction from the liver of rats induced with alpha-naphthoflavone and phenobarbital. The IC50S were in the 80-250 microM range for ...
Pan Y H - - 1997
We have reported previously that the rodent carcinogen 2,4-diaminotoluene (2,4-DAT) is not activated as a mutagen to the standard Ames S. typhimurium tester strains when oxidized by prostaglandin H synthase (PHS). 2,4-DAT does, however, enhance the bacterial mutagenicity of the potent mutagen 2-aminofluorene (2-AF) when both compounds are incubated with ...
Leyer G J - - 1997
Acid adaptation of Salmonella typhimurium at a pH of 5.0 to 5.8 for one to two cell doublings resulted in marked sensitization of the pathogen to halogen-based sanitizers including chlorine (hypochlorous acid) and iodine. Acid-adapted S. typhimurium was more resistant to an anionic acid sanitizer than was its nonadapted counterpart. ...
Matlho G - - 1997
A factorial laboratory experiment was conducted to assess the effects of heating times of 0, 20, 40, and 80 sec at 160 F and propionic acid concentrations of 0, 0.1%, and 0.2% on reduction of Salmonella enteritidis in poultry feed with approximately 15% moisture. The results showed that after 80 ...
Wilson J D JD - - 1997
Sodium azide, when added to wells adjacent to untreated wells, caused an increase in the reversion rate of Salmonella typhimurium TA100 in a 12-well plate format. Increases in the reversion frequency in adjacent, untreated wells were observed when a single well on the plate was treated with as little as ...
Uleckiené Saulé - - 1997
An International Agency for Research on Cancer (IARC) committee recognized aerosol of sulphuric acid as a human carcinogen on the basis of epidemiological studies. No experimental studies on the carcinogenicity, either of sulfuric acid aerosol or of sulfuric acid itself was available. Our aim was to determine whether sulfuric acid ...
Schimmer O - - 1996
Two methoxylated xanthone derivatives, eustomin and demethyleustomin, were isolated from the aerial parts of Centaurium erythraea Rafn. Both compounds were identified by spectral analysis. They showed strong antimutagenic properties in Salmonella typhimurium strains TA98, TA100, and TA102, when tested against 2-nitrofluorene, 2-aminoanthracene, ethyl methanesulfonate, and nalidixic acid. The bioantimutagenic character ...
Lee-Chen S F - - 1996
Chewing betel quid has been linked to the development of oral cancer. In Taiwan, fresh Piper betle inflorescence is uniquely added to betel quid, and hydroxychavicol is the major phenolic components of P.betle inflorescence. In this study, we tested the mutagenic potential of hydroxychavicol in Salmonella typhimurium TA97, TA98, TA100 ...
Bernacchi F - - 1996
Two coal-derived humic substances (Sulcis and South Africa, Eniricerche, Italy) have been evaluated for their mutagenic activity on TA98 and TA100 Salmonella typhimurium strains, either in presence or in absence of metabolic activation (S9). Both compounds showed no effect on the two strains, as observed with natural humic acid (Fluka). ...
Ribas G - - 1996
The induction of sister-chromatid exchanges (SCE) in cultured human lymphocytes by four inhibitors of DNA topoisomerases: m-amsacrine, camptothecin, etoposide and nalidixic acid has been evaluated. Although the four compounds apparently increase the frequency of SCE, the effect of nalidixic acid is weak because only a statistically significant positive response was ...
Jaegle L - - 1996
Simultaneous observations of stratospheric organic and inorganic chlorine were made in September 1993 out of Fort Sumner, New Mexico, using JPL balloon-borne MkIV interferometer. Between 15 and 20 km, a significant fraction (20-60%) of the inorganic chlorine could not be accounted for by the sum of measured HCl, ClONO2, and ...
Okai Y - - 1996
Effects of retinoids, carotenoids and antioxidant vitamins were studied by mutagen-induced umu C gene expression system in Salmonella typhimurium (TA 1535/pSK 1002). Retinol (vitamin A), retinol acetate and retinoic acid showed remarkable inhibitory activities, whereas retinol palmitate exhibited significant but weak activity for umu C gene expression in tester bacteria ...
Sindhu R K - - 1996
Six-week-old ferrets were exposed head-only to clean air or environmental tobacco smoke (ETS) at an average particulate concentration of 38 +/- 13 mg/m3 for 2 h/d, 5 d/wk for up to 15 wk. Twenty four hours after last exposure, the ferrets were sacrificed and the metabolism of benzo[a]pyrene and (-)-7R-trans-benzo[a]pyrene-7,8-dihydrodiol ...
Anke H - - 1996
Cibaric acid (1) and 10-hydroxy-8-decenoic acid (2) are two fatty acid derivatives that are formed in the fruit bodies of Cantharellus cibarius (chanterelle) and C. tubaeformis as a response to injury. Unlike the potent defensive sesquiterpenes formed in injured fruit bodies of the pungent Lactarius species, compounds 1 and 2 ...
Berchieri A A - - 1996
The experiment described evaluated the effect of a commercial in-feed preparation (Bio-Add) involving a mixture of formic acid and propionic acid on the incidence of experimental fowl typhoid in groups of 41 and 42 1-wk-old Rhode Island Red chickens. The chickens were infected through contact with 12 identical chickens that ...
Barch D H - - 1996
Ellagic acid is a complex planar molecule which demonstrates a variety of anticarcinogenic activities. Ellagic acid has been shown to inhibit the CYP1A1-dependent activation of benzo[a]pyrene; to bind to and detoxify the diolepoxide of benzo[a]pyrene; to bind to DNA and reduce the formation of O6-methylguanine by methylating carcinogens; and to ...
Yamada J - - 1996
Effects of caffeic acid and chlorogenic acid on mutagenicity were studied using the Salmonella typhimurium system. These compounds had inhibitory effects on the mutagenicity of Trp-P-1 and Glu-P-2. Caffeic acid completely eliminated the mutagenicity induced by activated Glu-P-2. Some compounds analogous to caffeic acid, such as cinnamic acid, coumaric acid, ...
Gaspar J - - 1996
The mutagenic activity of glycine upon nitrosation was studied in the Ames tester strains TA98, TA100, TA102, and TA104. The results obtained show that glycine at acidic pH values and in the presence of Cl- can react with nitrite giving rise to genotoxic compounds to the tester strains used. When ...
Amin S - - 1996
Tobacco-specific N-nitrosamines (TSNA) are the most abundant, strong carcinogens in tobacco smoke. Seven TSNA have been identified in tobacco products: N'-nitrosonornicotine (NNN), N'-nitrosoanabasine (NAB), N'-nitrosoanatabine (NAT), 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK), 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL), 4-(methylnitrosamino)-4-(3-pyridyl)-1-butanol (iso-NNAL), and 4-(methylnitrosamino)-4-3-pyridyl)butyric acid (iso-NNAC). The syntheses of these compounds are reviewed. The syntheses of 14C- and 3H-labeled NNK ...
Mizuno M - - 1996
A reflux of pancreatic juice into the biliary tract due to pancreaticobiliary malfunction has been considered to be an important factor in the development of biliary tract carcinogenesis. It is known that the contents of the biliary tract contain not only activated pancreatic enzymes but also certain mutagens. The purpose ...
Fábregas J J Department of Microbiology. Faculty of Pharmacy, University of Santiago, E-15706, Santiago de Compostela, - - 1996
The marine microalga Phaeodactylum tricornutum was cultivated in semi-continuous culture under mixotrophic conditions with the soluble fractions of potato, rye and wheat flours that had been naturally fermented, at 2% or 4% (w/v). The rye flour produced the highest microalgal cellular density of 90×10(6) cells.ml(-1) when supplemented with NaNO3 and ...
Kono Y - - 1995
N-Nitrosation of a model aromatic amine (2,3-diamino-naphthalene) by the N-nitrosating agent produced by nitrite in acidic solution was inhibited by a polyphenol, chlorogenic acid, which is an ester of caffeic acid quinic acid. Caffeic acid also inhibited the N-nitrosation, but quinic acid did not. 1,2-Benzenediols and 3,4-dihydroxybenzoic acid had inhibitory ...
Lauterwein M - - 1995
Secondary metabolites of different species of lichen were tested for their activities against a variety of microbial species. While gram-negative rods and fungi were not inhibited by these compounds, Staphylococcus aureus, Enterococcus faecalis, Enterococcus faecium, and some anaerobic species (Bacteroides and Clostridium species) were susceptible at the concentrations tested. Vulpinic ...
Jeong H K - - 1995
Hydroxylation of a meso-anthracenic carbon atom with subsequent formation of a reactive ester bearing a good leaving group (e.g., sulfate) has been proposed as a possible biochemical mechanism responsible for DNA binding, mutagenicity and tumorigenicity of 3-methylcholanthrene, one of the most potent carcinogenic polycyclic aromatic hydrocarbons in experimental animals. In ...
Hipkiss A R - - 1995
The dipeptide carnosine (beta-alanyl-L-histidine) was readily glycosylated non-enzymatically upon incubation with the sugars glucose, galactose, deoxyribose and the triose dihydroxyacetone. Carnosine inhibited glycation of actyl-Lys-His-amide by dihydroxyacetone and it protected alpha-crystallin, superoxide dismutase and catalise against glycation and cross-linking mediated by ribose, deoxyribose, dihydroxyacetone, dihydroxyacetone phosphate and fructose. Unlike certain ...
Isomaa B - - 1995
The cytotoxicity of the, in Salmonella, potent mutagenic compound, 3-chloro-4-(dichloromethyl)-5-hydroxy-2(5H)-furanone (MX) and its structural analogue 3,4-dichloro-5-hydroxy-2[5H]-furanone (mucochloric acid, MCA), was studied in freshly isolated rainbow trout hepatocytes and gill epithelial cells by determining 86Rb-leakage and decrease in fluorescence intensity in calcein AM-loaded cells. The acute toxicity of the compounds to ...
Kono Y - - 1995
Nitrite inhibited the killing of Escherichia coli by hypochlorous acid. The protection curve was sigmoid. Complete protection occurred at nitrite concentrations greater than that of hypochlorous acid. Hypochlorous acid reacts rapidly with nitrite, as shown by phenolic nitration, using 4-hydroxyphenylacetic acid. The nitration was biphasic. Amines and amino acids inhibited ...
Frémy J M - - 1995
Patulin is immunosuppressive and there is limited evidence of its carcinogenicity in experimental animals. The International Agency for Research on Cancer (IARC) initiated a programme for the development of degradation techniques for the commonly investigated mycotoxins. As a part of this programme, the following techniques were tested for the degradation ...
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