Cells defective in one or more aspects of repair are killed and often mutagenized more readily than normal cells by DNA damaging agents, and humans whose cells are deficient in repair are at an increased carcinogenic risk compared to normal individuals. The excision repair of uv induced pyrimidine dimers is a well studied system, but the details of the steps in this repair system are far from ...

Normal human and XP/sup 2/ fibroblasts were treated with uv plus uv-mimetic chemicals. The uv dose used was sufficient to saturate the uv excision repair system. Excision repair after combined treatments was estimated by unscheduled DNA synthesis, BrdUrd photolysis, and the loss of sites sensitive to a uv specific endonuclease. Since the repair of damage from uv and its mimetics is coordinately ...

Excision repair of DNA damage was measured by the photolysis of bromodeoxyuridine incorporated during repair in normal human and xeroderma pigmentosum group C fibroblasts (XP C) treated with a combination of the carcinogens N-acetoxy-2-acetylamino fluorene (AAAF), and 4-nitroquinoline 1-oxide (4NQO). Repair was additive in normal and ...

Candida albicans is a common opportunistic pathogen found in the oral mucosa. Clinical observations indicate a significant positive association between oral Candida carriage or infection and oral epithelial dysplasia/neoplasia. The aim of this study was to test whether C. albicans is able to promote epithelial dysplasia or carcinoma in a mouse model of infection where a carcinogen (4 ...

Candida albicans is a common opportunistic pathogen found in the oral mucosa. Clinical observations indicate a significant positive association between oral Candida carriage or infection and oral epithelial dysplasia/neoplasia. The aim of this study was to test whether C. albicans is able to promote epithelial dysplasia or carcinoma in a mouse model of infection where a carcinogen (4 ...

Previously we showed that the organoselenium compound, 1,4-phenylenebis(methylene)selenocyanate (p-XSC)1 inhibits 4-nitroquinoline-N-oxide (4-NQO)-induced tongue tumorigenesis in Fisher rats. Here we investigate possible mechanisms of this inhibition by monitoring mutagenesis and p53 protein levels in lacI and conventional Fisher rats treated with: 1) a ...

Several cell culture and animal studies demonstrated that citrus limonoids have protective effects against certain types of cancer. These chemopreventive properties of citrus limonoids are attributed to the induction of phase II enzyme, glutathione Stransferase (GST). In the current study, six citrus limonoids and two modified limonoids were utilized for the evaluation of NAD(P)H: quinone ...

Semi-whole blood microcultures were prepared from venous blood of a XP patient and from the blood of a normal adult. Cells were collected by centrifugation and treated with MMS or 4 NQO in a medium containing /sup 3/H- thymidine. With regard to the repair capacity of the XP cells, the levels of unscheduled incorporation of /sup 3/H-thymidine into ...

This thesis presents a study on the response of human epidermal keratinocytes to UV light as well as to other agents like 4-NQO and TPA. The effects of ultraviolet (UV) light on the protein synthesis in cultured keratinocytes are presented in ch. III. The...

Previously we showed that the organoselenium compound, 1,4-phenylenebis(methylene)selenocyanate (p-XSC)(1) inhibits 4-nitroquinoline-N-oxide (4-NQO)-induced tongue tumorigenesis in Fisher rats. Here we investigate possible mechanisms of this inhibition by monitoring mutagenesis and p53 protein levels in lacI and conventional Fisher rats treated with: (1) a ...

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 ...

d'Aerodynamique Appliquee (AAAF), Lille, November 1315, 1979. 47. Ivanov, S.K., Axial Flow Ventilation Fan, British Patent (112124303A), 1984. ...

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...

DNA damage and DNA repair in human fibroblasts induced by the combination mixture of the genotoxic agents methyl methanesulfonate (MMS) and 4-nitroquinoline-1-oxide (4-NQO) were studied using the comet assay and the unscheduled DNA synthesis (UDS), respectively. Cells were simultaneously treated for 1h with the no observed effect concentration (noec) of ...

The processes through which the UV-mimic chemical carcinogen, 4-nitroquinoline 1-oxide (4NQO), leads to the DNA lesions are well characterized in E. coli, where the formation of stable 4NQO-purine adducts is critical. The DNA excision-repair mechanisms similar to those for E. coli occur in normal human cells. ...

A wild-type Chinese hamster ovary cell line (CHO-9) and its uv-sensitive subclone (43-3B) have been used in characterizing the lethal and mutagenic effects of the chemical carcinogen, 4-nitroquinoline 1-oxide (4NQO). Cell survival as a function of 4NQO do...

Chromosomal changes of Yoshida ascites sarcoma cells induced in vitro by the minimal effective concentration (MEC) of 4-nitroquinoline-1-oxide (4NQO) were studied. Yoshida sarcoma cells were taken from Donryu rats bearing 4-day-old tumor ascites. Culture ...

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A single-copy gene, designated TruMDR2, encoding an ATP-binding cassette (ABC) transporter was cloned and sequenced from the dermatophyte Trichophyton rubrum. The ORF of TruMDR2 was 4048 nt and the deduced amino acid sequence showed high homology with ABC transporters involved in drug efflux in other fungi. The encoded ABC protein predicted 12 transmembrane segments (TMSs) and two almost identical ...

In the present study, we focused on the protective effect of Spirulina against 4-nitroquinoline-1-oxide (4NQO) induced hepato and nephrotoxicity in the experimental rats. The 4NQO administration resulted in increased levels of hepatic and renal markers [Alanine Transaminase (ALT), Aspartate Transaminase (AST), Lactate Dehydrogenase (LDH), urea, creatinine ...

Lecithin:retinol acyltransferase (LRAT) is an enzyme that converts retinol (vitamin A) to retinyl esters. Its expression is often reduced in human cancers, including oral cavity cancers. We investigated the effects of ectopic expression of human lecithin:retinol acyltransferase (LRAT) on murine oral cavity carcinogenesis induced by the carcinogen 4-nitroquinoline 1-oxide ...

Spearmint leaves (Mentha spicata L.) contain high levels of antioxidants that are known to protect against both exogenous and endogenous DNA damage. In this study, the protective effects of the hexane fraction (HF), chloroform fraction (CF) and ethyl acetate fraction (EAF) in an ethanol extract from M. spicata were evaluated against 4-nitroquinoline-1-oxide ...

Spearmint leaves (Mentha spicata L.) contain high levels of antioxidants that are known to protect against both exogenous and endogenous DNA damage. In this study, the protective effects of the hexane fraction (HF), chloroform fraction (CF) and ethyl acetate fraction (EAF) in an ethanol extract from M. spicata were evaluated against 4-nitroquinoline-1-oxide ...

Sesame oil could be considered as a potent antioxidant and dietary supplement. It possesses antimutagenic, anti-inflammatory and anti-cardiac toxicity. In the view of available findings, the current study focused on determining the protective effects of sesame oil on 4-Nitroquinoline-1-oxide (4-NQO) -induced oxidative DNA damage and lipid peroxidation ...

Objectives4-nitroquinoline 1-oxide (4NQO)-induced rat tongue carcinogenesis is a useful model for studying oral squamous cell carcinoma. However, gingival changes following 4NQO administration via drinking water are absent in the literature. The aim of this study was to investigate gingival changes concomitant to ...

Despite recent therapeutic advances, several factors, including field cancerization, have limited improvements in long-term survival for oral squamous cell carcinoma (OSCC). Therefore, comprehensive treatment plans must include improved chemopreventive strategies. Using the 4-nitroquinoline 1-oxide (4-NQO) mouse model, we tested the hypothesis that ZD6474 ...

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 ...

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 ...

, "Galileo Galilei (GG) - Test of the Equivalence Principle with a small Spinning satellite, Proceedings AAAF-ESA 3.74, 1996 [GG-A96] Galileo Galilei (GG): "Pre Phase A Report", ASI, 1996 [GG-Add97] Galileo Galilei (GG), "ADDENDUM No.1 to the Pre Phase A Report", ASI, 1997 [GG-A98] Galileo Galilei (GG

Three projects are described. The structure of nucleosome cores was studied using chymotrypsin as a probe of hydrophobic residues accessible on the core surface showed that only leu-20 of H3 was readily accessible, although other core histones were ultimately cleaved. Primary sites of cleavage of H2a, H2b, and H4 were identified. Carbon-13 NMR spectroscopic methods were used to examine nucleosome ...

Clonal variation has been studied in CHO cells. The variant phenotype was an altered morphology of clones in agar: the parental CHO cells give rise to solid clumps of cells (wild-type colonies); occasionally, dispersed colonies arise, and the cells display an invasive growth in agar (INGA-type colonies). The frequency of this altered phenotype can be enhanced by treatment with a variety of ...

The SOS chromotest was applied for the detection of antimutagens. To raise SOS induction, the bacteria were treated with the mutagens, UV, 4-nitroquinoline N-oxide (4NQO), N-methyl-N{prime}-nitro-N-nitroso-guanidine (MNNG), or benzo(a)pyrene (B(a)p). The inhibitory effects of {sub L}-ascorbic acid, glutathione, vanillin,5-fluorouracil (5-FU), ...

The aim of our study was to analyse desalivated rat tongue epithelium for histopathological changes, proliferating cell nuclear antigen (PCNA), and epithelium-associated stromal myofibroblasts [SMF; alpha-smooth muscle actin (alphaSMA)] following 0.001% 4-nitroquinoline 1-oxide (4NQO) administration in drinking water. Results were compared with those of ...

A cell's ability to tolerate DNA damage is directly connected to the human development of diseases and cancer. To better understand the processes underlying mutagenesis, we studied the cell's reliance on the potentially error-prone translesion synthesis (TLS), and an error-free, template-switching pathway in Saccharomyces cerevisiae. The primary proteins mediating S. cerevisiae TLS are three DNA ...

Diploid human fibroblasts (IMR-90 cells), grown to confluency and growth-arrested by serum starvation, were irradiated with a variety of doses of UV light (0.025-40 J/m[sup 2]) or incubated with broad dose ranges of four direct-acting mutagens [ethyl methanesulfonate (EMS), ICR-70, methyl methanesulfonate (MMS), and 4-nitroquinoline oxide (4-NQO)] and ...

BackgroundThe study was designed to investigate immunocompetence in relation to cancer progression in rat and to assess the effect of the traditional Chinese anti-cancer medicine, "Shenyang" prescription, on immunity.Methods4-Nitroquinoline-1-oxide (4NQO) was administered to 80 Sprague-Dawley (SD) rats via the drinking water for up to 36 weeks. Tongue ...

We have isolated 56 UV-sensitive mutant clones from a mouse L51 T/t line of L5178Y cells by a cell suspension spotting method. Five mutants have also been isolated from L51 T/t and L5178Y cells by the method reported by Thompson and coworkers. We divided the mutants into two groups, highly sensitive and moderately sensitive mutants, according to their sensitivity to UV irradiation. Fifty-eight ...

The present paper describes a marked induction of liver microsomal cytochrome P-450 and cytosolic DT-diaphorase to cause possible disorder of steroid homeostasis and promotion of carcinogenicity of 4-nitroquinoline N-oxide (4-NQO) in rats by pretreatment with 3,4,5,3',4'-pentachlorobiphenyl (PenCB) or 2,3,4,7,8-pentachlorodibenzofuran (PenCDF). The animals ...

The present paper describes a marked induction of liver microsomal cytochrome P-450 and cytosolic DT-diaphorase to cause possible disorder of steroid homeostasis and promotion of carcinogenicity of 4-nitroquinoline N-oxide (4-NQO) in rats by pretreatment with 3,4,5,3',4'-pentachlorobiphenyl (PenCB) or 2,3,4,7,8-pentachlorodibenzofuran ...

We have isolated a C. albicans gene, named FCR3 (for fluconazole resistance 3), based upon its ability to suppress the FCZ hypersusceptibility of a Saccharomyces cerevisiae mutant strain (JY312) lacking the transcription factors Pdr1p and Pdr3p. The FCR3 ORF (1200 bp) encodes a 399 amino acid protein containing a basic leucine zipper (bZip) domain. Fcr3p displays the highest level of sequence ...

Alcohol drinking is a known risk factor for oral cancer in humans. However, previous animal studies on the promoting effect of ethanol on oral carcinogenesis were inconclusive. It is necessary to develop an animal model with which the molecular mechanism of ethanol-related oral carcinogenesis may be elucidated in order to develop effective prevention strategies. In this study, mice were first ...

The cyclin D1 oncogene is frequently amplified/overexpressed in oral squamous cell carcinomas. Mice with overexpression of cyclin D1 targeted to the stratified squamous epithelia of the tongue, esophagus and forestomach develop a phenotype of epithelial dysplasia at these sites. In this study, we examined the effect cyclin D1 overexpression on susceptibility of mice to carcinogen-induced ...

In four experiments, concentrated glycerin suspensions of 7,12-dimethylbenz(a)anthracene (DMBA), or the water-soluble compounds, N-methyl-N-nitrosourea (MNU), N-ethyl-N-nitrosourea (ENU), and 4-nitroquinoline-N-oxide (4-NQO) were delivered into pockets in the mammary fat pads in female Sprague-Dawley rats. In a 90-day experiment, each of three groups of ...

The dysplastic nevus syndrome (DNS) is a preneoplastic melanocyte abnormality which occurs in families affected by hereditary cutaneous malignant melanoma (HCMM). A putative role of host-environmental interactions in the etiology of hereditary melanoma has been strengthened by the recent finding that fibroblasts derived from HCMM/DNS patients demonstrated enhanced sensitivity to u.v.-irradiation ...

Despite numerous advances, the 5-year survival rate for head and neck squamous cell cancer (HNSCC) has remained largely unchanged. This poor outcome is due to several variables, including the development of multiple primary tumors. Therefore, it is essential to supplement early detection with preventive strategies. Using the 4-nitroquinoline 1-oxide ...

The transcriptional silencing of some cell cycle inhibitors and tumor suppressors, such as p16 and retinoic acid receptor beta(2), by DNA hypermethylation at CpG islands is commonly found in human oral squamous carcinoma cells. We examined the effects of the DNA methyltransferase inhibitor 5-Aza-2'-deoxycytidine (5-Aza; 0.25 mg/kg body weight), all-trans retinoic acid (RA; given at 100 microg/kg ...

The transcriptional silencing of some cell cycle inhibitors and tumor suppressors, such as p16 and RAR?₂, by DNA hypermethylation at CpG islands is commonly found in human oral squamous carcinoma cells. We examined the effects of the DNA methyltransferase (Dnmt) inhibitor 5-Aza-2'-deoxycytidine (5-Aza, 0.25 mg/kg body weight), all-trans retinoic acid (RA, given at 100 ...

We have examined, at the DNA sequence level, the sequence preferences of binding of six chemicals to linear DNA. The chemicals utilized were the bis-(1,10)-phenanthroline Cu(I) complex ((Phen)/sub 2/Cu/sup +/), (+)-anti-and (/minus/)-anti isomers of benzo(a)pyrene-7,8-diol-9, 10-epoxide (BPDE), acetylacetoxyamino-fluorene (AAAF), 8-azido-ethidium (AEt), and 7-azido-actinomycin ...

Studies of the structure of nucleosome cores using chymotrypsin as a probe of hydrophobic residues showed that only leu-20 of H3 was readily accessible. Primary sites of cleavage of H2a, H2b, and H4 were identified. Chymotrypsin removal of specific histone termini showed that removal of the amino-terminal plus the carboxy-terminal 13 residues of H2a caused little unfolding. Using carbon-13 NMR ...

The tunable dye laser was developed in order to perform UV-B and UV-C (254-320 nm) action spectra studies on several different organisms. Using the laser, action spectra studies have been performed for Escherichia coli, Saccharomyces, Chlamydomonas, Caenorhabditis elegans, Paramecium, and Tetrahymena pyriformis. Studies generally indicate increasing LD{sub 50} values with increasing wavelength. ...

The carcinogenic drug 4-nitroquinoline-1-oxide (4NQO) has been found to bind with the protein hen egg white lysozyme as evident from fluorescence quenching experiments. The binding constant and stoichiometry have been determined. The values of the thermodynamic parameters indicate that the interaction is an enthalpy-driven spontaneous phenomenon. The ...

We report on a novel approach to predict the mode of genotoxic action of chemicals using a series of DNA damage specific bioluminescent bacteria. For this, a group of seven different DNA damage sensing recombinant bioluminescent strains were employed. Each of these strains was tested against model DNA damaging agents, such as mitomycin C (MMC), 1-methyl-1-nitroso-N-methylguanidine (MNNG), ...

The authors report studies of oncogene transcription induced by the addition of serum to quiescent cultures of human IMR-90 fibroblasts. Oncogene messenger RNAs for c-myc, c-erbB and c-ras were increased in a specific temporal sequence after the addition of serum. Compounds that are proposed to exert their actions by the stimulation of cell growth were tested for their effect on oncogene ...

Dichloromethane extracts from different parts of Rhamnus prinoides, Ornithogalum longibracteatum, Gardenia volkensii, Spirostachys africana, Diospyros whyteana, Syzigium cordatum and Prunus africana were investigated for mutagenic and antimutagenic effects in Salmonella/microsome and micronucleus tests. None of the extracts tested in the Ames test were found to induce mutations or to modify the ...

The effects of ozonation on the formation potential of typical disinfection byproducts (DBPs) and the changes of genotoxicity during post chlorination of tertiary effluent from a sewage treatment plant were investigated. Ozonation enhanced the yields of all detected chlorine DBPs except CHCl3. At a chlorine dose of 5 mg/L, the three brominated THMs and five HAAs increased, while chloroform ...

The effects of polyamines and related compounds on the development of drug/antibiotic resistance in a variety of bacterial strains were studied. Methods employed included standard toxicity assays, modified Ames tests for mutation frequencies and antimutagenic effects, prophage induction assays, and recA-lacZ and ada-lacZ induction assays. Using these methods, we have shown that the polyamines ...

The basidiomycete Moniliophthora perniciosa causes Witches' Broom disease in Theobroma cacao. We studied the influence of carbon source on conditioning hyphae to oxidative stress agents (H(2)O(2), paraquat, 4NQO) and to UVC, toward the goal of assessing the ability of this pathogen to avoid plant defenses involving ROS. Cells exhibited increased resistance ...

Antimutagenic, anticlastogenic, and bioprotective effect of polysaccharide glucomannan (GM) isolated from Candida utilis was evaluated in four model test systems. The antimutagenic effect of GM against 9-aminoacridine (9-AA)- and sodium azide (NaN3)-induced mutagenicity was revealed in the Salmonella typhimurium strains TA97 and TA100, respectively. GM showed anticlastogenic effect against ...

Increased awareness of the role of environmental factors in carcinogenesis has led to an emphasis on preventing or minimizing exposure to genotoxicants. This is presently promoting the development of simple, rapid, cost-effective mutagenicity screening assays. We have developed a test system based on the well-known Salmonella mutagenicity assay. The lux genes, which permit cells to emit light ...

The centrosome is a cytoplasmic organelle which duplicates once during each cell cycle, and the presence of excess centrosomes promote chromosome instability through chromosome missegregation following cytokinesis. Ionizing radiation (IR) can induce extra centrosomes by permitting the continuation of CDK2/Cyclin-A/E-mediated centrosome duplication when cells are arrested in the cell cycle after ...

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 ...

The medium-term tongue carcinogenesis assay is a useful model for studying oral squamous cell carcinomas phase by phase. The aim of the present study was to investigate the expression of p53 by immunohistochemistry and examine the DNA sequence of exons 5, 6, 7, and 8 of Tp53 for mutations during rat tongue carcinogenesis induced by 4-nitroquinoline 1-oxide ...

We identified two predicted proteins in Schizosaccharomyces pombe, Rrp1 (SPAC17A2.12) and Rrp2 (SPBC23E6.02) that share 34% and 36% similarity to Saccharomyces cerevisiae Ris1p, respectively. Ris1p is a DNA-dependent ATP-ase involved in gene silencing and DNA repair. Rrp1 and Rrp2 also share similarity with S. cerevisiae Rad5 and S. pombe Rad8, containing SNF2-N, RING finger and Helicase-C ...

Cockayne syndrome (CS) is a human genetic disorder characterized by UV sensitivity, developmental abnormalities, and premature aging. Two of the genes involved, CSA and CSB, are required for transcription-coupled repair (TCR), a subpathway of nucleotide excision repair that removes certain lesions rapidly and efficiently from the transcribed strand of active genes. CS proteins have also been ...

Rhabdoid tumors (RT) are aggressive tumors characterized by genetic loss of SMARCB1 (SNF5, INI-1), a component of the SWI/SNF chromatin remodeling complex. No effective treatment is currently available. This study seeks to shed light on the SMARCB1-mediated pathogenesis of RT and to discover potential therapeutic targets. Global gene expression of 10 RT was compared with 12 cellular mesoblastic ...

The aim of this work was to examine the antigenotoxic potential of plant monoterpenes: camphor, eucalyptol and thujone in prokaryotic and eukaryotic cells and to elucidate their effect on DNA repair. We compared the effect of monoterpenes on spontaneous, UV- and 4NQO-induced mutagenesis in Escherichia coli K12 repair proficient, and MMR and NER deficient strains. Positive controls tannic acid and ...

The progression of papillomas to squamous cell carcinomas (malignant conversion) was studied in the skin of SENCAR and Charles River CD-1 mice, using a three-stage treatment protocol. After initiation with 7,12-dimethylbenz(a)anthracene (DMBA) (stage I) and limited promotion by 12-O-tetradecanoylphorbol-13-acetate (TPA) (stage II), papilloma-bearing mice were treated (stage III) with either tumor ...

Cell surface glycoconjugates were investigated in a rat model of oral chemical carcinogenesis. The lectins Griffonia simplicifolia (GS-I-B4; specific for alpha-D-galactosyl end groups) and Ulex europeus (UEA-I; specific for alpha-L-fucosyl groups) were examined microspectrofluorimetrically in the oral epithelium of rats painted with the carcinogen 4-nitroquinoline N-oxide ...

Previous studies have indicated the chemoprevention potential of citrus limonoids due to the induction of phase II detoxifying enzymes. In the present study, three citrus limonoids were purified and identified from sour orange seeds as limonin, limonin glucoside (LG), deacetylnomilinic acid glucoside (DNAG). In addition, limonin was modified to defuran limonin and limonin 7-methoxime. The ...

A wild-type Chinese hamster ovary cell line (CHO-9) and its uv-sensitive subclone (43-3B) have been used in characterizing the lethal and mutagenic effects of the chemical carcinogen, 4-nitroquinoline 1-oxide (4NQO). Cell survival as a function of 4NQO dose was determined for exponential and growth arrested populations of both cell lines. During ...

The accident at the Chernobyl nuclear power station in 1986 led to the dispersal of large amounts of a variety of radioactive materials, most importantly uranium, plutonium, 137Cs, 131I and 90Sr, over very large distances estimated to reach as far as Sweden, Norway, Turkey and possibly the USA. As a consequence, the soil on which the radioactive materials fell was contaminated and the degree of ...

A study was conducted in rats with early tongue carcinoma induced by 4-nitroquinoline 1-oxide (4NQO), in order to investigate the early diagnosis of malignant potential of epithelial dysplasia. The rat tongue lesions were classified by their severity into three groups corresponding to early cancer, dysplasia and no change. The grade of epithelial changes ...

Chemoprevention of head and neck squamous cell carcinoma (HNSCC), a disease associated with high mortality rates and frequent occurrence of second primary tumor (SPT), is an important clinical goal. The epidermal growth factor receptor (EGFR)-signal transducer and activator of transcription (STAT)-3 signaling pathway is known to play a key role in HNSCC growth, survival, and prognosis, thereby ...

BALB/c-3T3 cells were employed to examine the genotoxic potential of a variety of known chemical carcinogens. BALB/c-3T3 cells displayed a dose-dependent transformation response to a variety of carcinogens (polycyclic hydrocarbons, methylating agents, ethylating agents, aflatoxin B{sub 1} (AFT{sub 1}), and 4-nitroquinoline-N-oxide (4-NQO)). When the ...

Sulphonated phthalocyanines are studied as photosensitizers for photodynamic therapy of cancer. Their strong fluorescence and tumour-localising properties make them also potentially useful for detection of cancer by fluorescence. For this purpose, we have studied the fluorescence kinetics and localisation of aluminum phthalocyanine disulphonate (AlPcS2) in 4-nitroquinoline 1-oxide ...

Because of a possible etiologic link between mutations and carcinogenesis, the authors compared fibroblasts derived from skin biopsies of several patients with hereditary cutaneous malignant melanoma and the dysplastic nevus syndrome for sensitivity to the mutagenic and/or cytotoxic effect of broad-spectrum simulated sunlight and of a UV mimetic carcinogen, 4-nitroquinoline 1-oxide ...

Peromyscus leucopus (white-footed mouse) and Cryptotis parva (least shrew) possess desirable attributes for biomonitoring contamination of terrestrial ecosystems, but few studies have examined the potential use of these species for monitoring exposure to genotoxic contaminants. The susceptibility of laboratory-reared C. parva, P. leucopus, and Mus musculus (house mouse, strain CD-1) to ...

Mutagen-induced intergenic and interallelic recombination as well as forward mutation were studied in one and the same strain of S. cerevisiae. In nontoxic dose ranges, the induction of mutants and recombinants was parallel after treatment with ethyl methanesulfonate (EMS), methyl methanesulfonate (MMS), N-methyl-N'-nitro-M-nitrosoguanidine (MNNG), triethylene melamine (TEM), 4-nitroquinoline ...

The enzyme ribonucleotide reductase, responsible for the synthesis of deoxyribonucleotides (dNTP), is upregulated in response to DNA damage in all organisms. In Saccharomyces cerevisiae, dNTP concentration increases ?6- to 8-fold in response to DNA damage. This concentration increase is associated with improved tolerance of DNA damage, suggesting that translesion DNA synthesis is more efficient at ...

In mammalian cells it has previously been observed that low DNA-repair activity is correlated with high chromosome-aberration frequency. Since fish cells typically express comparatively low amounts of DNA repair, the chromosome aberration test holds potential as a sensitive fish genotoxicity assay. A comparison of in vitro DNA-repair activity showed HF greater than CHO greater than Ul-H = Ul-F ...

Pathogenic processes have been identified that could associate chronic stress and cancer, but these findings have not been observed in oral cancer. This study examined the role of chronic restraint stress on the incidence and severity of OSCC induced with 4-nitroquinoline-1-oxide (4-NQO) in the tongues of CF-1 mice. One hundred twenty CF-1 male mice were ...

ZengShengPing (ZSP), a mixture of six medicinal herbs, has been reported to prevent esophageal squamous cell carcinoma (SCC) in human patients with dysplasia. This study was designed to investigate the chemopreventive effects of ZSP on oral cancer in animal models and human patients. In the 7,12-dimethylbenz[a]anthracene (DMBA)-induced hamster cheek pouch model, ZSP (6g/kgBW/day by gavage for 10 ...

The effects of the carcinogens (4NQO, 4-nitroquinoline-N-oxide; MNNG, N-methyl-N'-nitro-N-nitrosoguanidine; AFLG1, aflatoxin G1; AFLB1, aflatoxin B1; BNU, butylnitrosourea; MNU, methylnitrosourea) and the tumor promoter (TPA, 12-O-tetradecanoylphorbol-13-acetate) on sister chromatid exchanges (SCE), chromosome aberrations and colony formation (CF) were ...

Demethylation inhibitor (DMI)-resistant strains of the plant pathogenic fungus Penicillium digitatum were shown to be simultaneously resistant to cycloheximide, 4-nitroquinoline-N-oxide (4NQO), and acriflavine. A PMR1 (Penicillium multidrug resistance) gene encoding an ATP-binding cassette (ABC) transporter (P-glycoprotein) was cloned from a genomic DNA ...

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 so as to accommodate the sequence ...

We now have a reliable program for computing single stranded and duplex structures of carcinogen-modified DNA's to the dodecamer level, and are beginning to understand the conformational effects that polycyclic aromatic amines and hydrocarbons impose om modified DNA. A hypothesis relating mutagenicity and conformation has in fact emerged directly from the calculations. In addition, work ...

BackgroundSeveral cell culture and animal studies demonstrated that citrus bioactive compounds have protective effects against certain types of cancer. Among several classes of citrus bioactive compounds, limonoids were reported to prevent different types of cancer. Furthermore, the structures of citrus limonoids were reported to influence the activity of phase II detoxifying enzymes. The purpose ...

The measurement of serine139-phosphorylated histone H2AX (?H2AX) provides a biomarker of DNA double-strand breaks (DSBs) and may identify potential genotoxic activity. In order to evaluate a flow cytometry assay for ?H2AX detection (hereafter termed the ?H2AX by flow assay), 6 prototypical (3 pro- and 3 proximate) genotoxins, i.e. dimethylbenz[a]anthracene (DMBA), 2-acetylaminofluorene (2-AAF), ...

Two types of purified samples, water-soluble (sample A; M. W, 1.2 x 10(6) dalton) and water-insoluble (sample C; M. W., 1.0 x 10(6) dalton) samples, were obtained through consecutive separation processes from the culture broth of Ganoderma lucidia mycelium. It was found that both samples from the culture broth were very effective in inhibiting the growth of several human cancer cell lines, having ...

Reconstituted non-fat dry milk powder, fermented by a mixture of Streptococcus thermophilus CH3 and Lactobacillus bulgaricus 191R to produce yogurt, was freeze-dried and extracted in acetone. After evaporation of the acetone, the extract was dissolved in dimethyl sulfoxide (DMSO) and tested for antimutagenicity. In the Ames test, significant dose-dependent activity was observed against ...

Insulin-like growth factor (IGF)-I regulates a mutually exclusive interaction of PP2A and beta1 integrin with the WD repeat scaffolding protein RACK1. This interaction is required for the integration of IGF-I receptor (IGF-IR) and adhesion signaling. Here we investigated the nature of the binding site for PP2A and beta1 integrin in RACK1. A WD7 deletion mutant of RACK1 did not associate with PP2A ...

Created in 1994 in the wake of the closure of the Space Camp of Patrick Baudry in Cannes, Classes Azur Astro Espace (AAE) provide a world's unique combination of space and astronomy courses, as given by active and retired professionals of two of the best space and astronomical facilities extant: Alcatel Space in Cannes and Observatoire de la C�te d'Azur (OCA) in Nice, Grasse and Caussols. ...

The anti-tumor properties of arsenic trioxide have attracted extensive attention after successfully inducing apoptosis of acute promyelocytic leukemia cells. However, the therapeutic spectrum should not only be restricted to acute promyelocytic leukemia, but should also extend into other types of tumor cells. In this study, we aimed at investigating its potential application to clinical ...