Methylnitrosourea
Mostrando 1-12 de 20 artigos, teses e dissertações.
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1. Punica granatum suppresses colon cancer through downregulation of Wnt/β-Catenin in rat model
Abstract This study aims to elucidate the beneficial effect of Punica granatum L., Lythraceae (pomegranate) peel extract in the management of colon cancer induced intrarectally with N-methylnitrosourea. Adult male Sprague-Dawley rats were administered N-methylnitrosourea (2 mg in 0.5 ml water/rat) intrarectally three times/week for five weeks to induce color
Rev. bras. farmacogn.. Publicado em: 2017-10
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2. Differences between NMRI and DBA/2J mice in the development of somites and susceptibility to methylnitrosourea-induced skeleton anomalies
ABSTRACT The development of DBA/2J mouse strain embryos is nearly 12 h - or 6 somite pairs - delayed as compared to the outbred NMRI mouse embryos of the same age on gestation days (GD) 8-12. To evaluate inter-strain differences in susceptibility to teratogens, dams were treated with methylnitrosourea (MNU, 5 mg/kg body weight i.p.) on defined gestation days
An. Acad. Bras. Ciênc.. Publicado em: 2017-05
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3. Avaliação do potencial genotóxico e cancerígeno do lodo de estação de tratamento de esgoto (LETE) em sistemas experimentais in vivo / In vivo evaluation of the carcinogenic potential of sewage sludge from a urban wastewater treatment plant in experimental systems
A rápida oxidação da matéria orgânica dos solos tropicais é mais uma evidência da grande vantagem do uso de biossólidos como condicionadores, capazes de melhorar as características físicas, químicas e biológicas do solo com grandes reflexos na produtividade agrícola. Portanto, o presente projeto objetivou averiguar o potencial genotóxico e canc
Publicado em: 2009
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4. Transfer of human genes conferring resistance to methylating mutagens, but not to UV irradiation and cross-linking agents, into Chinese hamster ovary cells.
Chinese hamster ovary cells were transfected by human DNA ligated to the bacterial gpt (xanthine-guanine-phosphoribosyltransferase) gene which was used either in its native form or after partial inactivation with methylnitrosourea. The gpt+ transfectants were screened for resistance to high doses of N-methyl-N'-nitro-N-nitrosoguanidine. Using this approach,
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5. Evidence that carcinogenesis involves an imbalance between epigenetic high-frequency initiation and suppression of promotion.
Evidence is presented in support of the hypothesis that cancer development depends on an imbalance between highly frequent epigenetic initiation and suppression of promotion of the initiated cells. When irradiated clonogenic mammary epithelial cells are transplanted and hormonally stimulated, they give rise to clonal glandular structures within which carcino
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6. Nearest neighbor effects on carcinogen binding to guanine runs in DNA.
A synthetic DNA fragment was constructed to determine the effect of 5' and 3' neighbors of guanine runs on the binding of chemical carcinogens. Determinations were made on the relative intensity of reactivity between aflatoxin B1 or benzo(a)pyrene and methylnitrosourea or 1-(2-chloroethyl)-3-cyclohexyl-1-nitrosourea with various guanine positions in an endla
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7. A system in mouse liver for the repair of O6-methylguanine lesions in methylated DNA.
An activity from mouse liver with catalyzes the disappearance of O6-methylguanine from DNA methylated with methylnitrosourea has been partially purified by ammonium sulfate fractionation and DNA-cellulose chromatography. The activity does not require divalent metal ions and is not affected by EDTA. It is specific for the repair of O6-methylguanine lesions an
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8. Endonuclease II, apurinic acid endonuclease, and exonuclease III.
An endonuclease of Escherichia coli active on a DNA treated with methylmethane sulfonate has been separated from an endonuclease active on depurinated sites. The former enzyme is disignated here as endonuclease II, while the latter enzyme is designated as apurinic acid endonuclease. Endonuclease II is also active on DNA treated with methylnitrosourea, 7-brom
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9. Separation of killing and tumorigenic effects of an alkylating agent in mice defective in two of the DNA repair genes
Alkylation of DNA at the O6-position of guanine is one of the most critical events leading to mutation, cancer, and cell death. The enzyme O6-methylguanine-DNA methyltransferase repairs O6-methylguanine as well as a minor methylated base, O4-methylthymine, in DNA. Mouse lines deficient in the methyltransferase (MGMT) gene are hypersensitive to both the killi
The National Academy of Sciences.
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10. Recognition of chemical carcinogen-modified DNA by a DNA-binding protein.
Using a filter binding assay, we have detected and partially purified a protein from human placenta that has a high affinity for N-acetoxy-2-acetylaminofluorene-modified double-stranded DNA (AAF-[3H]DNA) of bacteriophage T7. This protein has been partially purified from a 1 M NaCl extract of a crude nuclear fraction by a combination of ion-exchange and nucle
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11. Implication of Localization of Human DNA Repair Enzyme O6-Methylguanine-DNA Methyltransferase at Active Transcription Sites in Transcription-Repair Coupling of the Mutagenic O6-Methylguanine Lesion
DNA lesions that halt RNA polymerase during transcription are preferentially repaired by the nucleotide excision repair pathway. This transcription-coupled repair is initiated by the arrested RNA polymerase at the DNA lesion. However, the mutagenic O6-methylguanine (6MG) lesion which is bypassed by RNA polymerase is also preferentially repaired at the transc
American Society for Microbiology.
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12. Regulatory mechanisms for induction of synthesis of repair enzymes in response to alkylating agents: ada protein acts as a transcriptional regulator.
Expression of the ada and alkA genes, both of which are involved in the adaptive response of Escherichia coli to alkylating agents, is positively controlled by Ada protein, the product of the ada gene. Large amounts of ada- and alkA-specific RNA were formed in cells treated with a methylating agent, whereas little such RNA was produced in untreated cells. Th