A genetic cluster of patients with variant xeroderma pigmentosum with two different founder mutations.

BACKGROUND: Xeroderma pigmentosum (XP) is a rare human syndrome associated with hypersensitivity to sunlight and a high frequency of skin tumours at an early age. We identified a community in the state of Goias (central Brazil), a sunny and tropical region, with a high incidence of XP (17 patients among approximately 1000 inhabitants). OBJECTIVES: To identify gene mutations in the affected community and map the distribution of the affected alleles, correlating the mutations with clinical phenotypes. METHODS: Functional analyses of DNA repair capacity and cell-cycle responses after ultraviolet exposure were investigated in cells from local patients with XP, allowing the identification of the mutated gene, which was then sequenced to locate the mutations. A specific assay was designed for mapping the distribution of these mutations in the community. RESULTS: Skin primary fibroblasts showed normal DNA damage removal but abnormal DNA synthesis after ultraviolet irradiation and deficient expression of the Polη protein, which is encoded by POLH. We detected two different POLH mutations: one at the splice donor site of intron 6 (c.764 +1 G>A), and the other in exon 8 (c.907 C>T, p.Arg303X). The mutation at intron 6 is novel, whereas the mutation at exon 8 has been previously described in Europe. Thus, these mutations were likely brought to the community long ago, suggesting two founder effects for this rare disease. CONCLUSIONS: This work describes a genetic cluster involving POLH, and, particularly unexpected, with two independent founder mutations, including one that likely originated in Europe.

Genotoxicity investigation of araticum(Annona crassiflora Mart., 1841, Annonaceae) using SOS-Inductest and Ames test.

Although the use of medicinal plants or natural products has increased in recent decades all over the world, little information is available on their potential risk to health. Annona crassiflora Mart., a plant commonly known as araticum in Brazil, has been widely used in folk medicine for a long time since its seeds and leaves are often utilised in the treatment of cancer, snake bites, and venereal diseases, its fruits are consumed as tonic and astringent, and its bark powder has anti-fungal and anti-rheumatic properties. To evaluate the genotoxic and mutagenic properties induced by the ethanolic extract of araticum leaves, we performed the prophage λ induction (Inductest) and bacterial mutagenicity assays. We used Escherichia coli WP2s(λ) and RJF013 strains in the lysogenic induction test, whereas the mutagenic studies were carried out using Salmonella typhimurium histidine auxotroph strains TA97a, TA98, TA100, and TA102. Each experiment was performed three times in duplicate and included positive and negative controls. No statistically significant (p > 0.05) positive results were obtained for any of the strains tested, which suggests that the ethanolic extract of araticum leaves did not exhibit direct mechanisms of genotoxicity or mutagenicity that could be detected by the tests used in the present work.

Antimutagenicity protection of Ginkgo biloba extract (Egb 761) against mitomycin C and cyclophosphamide in mouse bone marrow.

Ginkgo biloba (Egb 761) extract, the most prescribed phytomedicine in Europe for the treatment of cerebral insufficiency and vascular diseases, was tested for its possible protective effects against mitomycin C (MMC)- and cyclophosphamide (CP)-induced mutagenicity using the micronucleus test in mouse bone marrow. The extract was co-administered to mice at doses of 50, 100 and 200 mg/kg (po) with 4 mg/kg (ip) MMC or 24 mg/kg (ip) CP. All doses of Egb 761 were significantly (P < 0.05) effective in reducing the frequency of micronucleated polychromatic erythrocytes, when compared with MMC or CP alone. Based on these results, we suggest that Egb 761 possesses both direct and indirect antimutagenic potential.

Assessment of the mutagenic, antimutagenic and cytotoxic activities of ethanolic extract of araticum (Annona crassiflora Mart. 1841) by micronucleus test in mice.

A typical Brazilian plant, araticum (Annona crassiflora Mart.), is widely used in humans as therapeutic medicine to treat several diseases such as diarrhea, rheumatism and syphilis. It contains acetogenins which present cytotoxic, antitumogenic, and antiparasitic properties. In this study, mutagenic, antimutagenic and cytotoxic effects of araticum leaves ethanolic extract were evaluated by micronucleus test in mice. To evaluate the mutagenic activity, animals were treated with ethanolic extract of araticum (EEA) using 10, 20, 50, 100 and 160 mg.kg(-1). For all doses, micronucleated polychromatic erythrocytes (MNPCE) frequency was evaluated at 24, 48 and 72 hours after treatment. To evaluate the antimutagenic activity, animals were treated with 10, 20, 50 and 100 mg.kg(-1) of EEA and 4 mg.kg(-1) of MMC simultaneously. The frequency of MNPCE was evaluated 36 hours after exposure. Cytotoxicity was evaluated by the polychromatic and normochromatic erythrocytes ratio (PCE/NCE). In the mutagenicity assessment, all doses of EEA resulted in no significant increase of MNPCE (P > 0.05), compared to solvent- control group. Regarding administration time, no significant difference among three evaluation periods was observed (P > 0.05). Such results indicate that EEA did not exert mutagenic activity. Cytotoxicity was evident in doses of 50, 100 and 160 mg.kg(-1) at 24 and 48 hours after exposure. Concerning antimutagenicity, except the 10 mg.kg(-1) co-administered with 4 mg/kg of MMC, all doses reduced significantly the frequency of MNPCE compared to the positive control group (P < 0.05). These results, therefore, indicate an antimutagenic activity of the EEA. Cytotoxicity was significantly increased (P < 0.01) at 100 mg.kg(-1) EEA doses co-administered with 4 mg.kg(-1) of MMC.

Assessment of the mutagenic, antimutagenic and cytotoxic activities of ethanolic extract of araticum (Annona crassiflora Mart. 1841) by micronucleus test in mice

A typical Brazilian plant, araticum (Annona crassiflora Mart.), is widely used in humans as therapeutic medicine to treat several diseases such as diarrhea, rheumatism and syphilis. It contains acetogenins which present cytotoxic, antitumogenic, and antiparasitic properties. In this study, mutagenic, antimutagenic and cytotoxic effects of araticum leaves ethanolic extract were evaluated by micronucleus test in mice. To evaluate the mutagenic activity, animals were treated with ethanolic extract of araticum (EEA) using 10, 20, 50, 100 and 160 mg.kg-1. For all doses, micronucleated polychromatic erythrocytes (MNPCE) frequency was evaluated at 24, 48 and 72 hours after treatment. To evaluate the antimutagenic activity, animals were treated with 10, 20, 50 and 100 mg.kg-1 of EEA and 4 mg.kg-1 of MMC simultaneously. The frequency of MNPCE was evaluated 36 hours after exposure. Cytotoxicity was evaluated by the polychromatic and normochromatic erythrocytes ratio (PCE/NCE). In the mutagenicity assessment, all doses of EEA resulted in no significant increase of MNPCE (P > 0.05), compared to solvent- control group. Regarding administration time, no significant difference among three evaluation periods was observed (P > 0.05). Such results indicate that EEA did not exert mutagenic activity. Cytotoxicity was evident in doses of 50, 100 and 160 mg.kg-1 at 24 and 48 hours after exposure. Concerning antimutagenicity, except the 10 mg.kg-1 co-administered with 4 mg/kg of MMC, all doses reduced significantly the frequency of MNPCE compared to the positive control group (P < 0.05). These results, therefore, indicate an antimutagenic activity of the EEA. Cytotoxicity was significantly increased (P < 0.01) at 100 mg.kg-1 EEA doses co-administered with 4 mg.kg-1 of MMC.

O araticum (Annona crassiflora Mart.) é uma planta tipicamente brasileira, largamente utilizada em humanos como remédio para o tratamento de diversas doenças como diarréia, reumatismo e sífilis. Esta planta contém acetogeninas que apresentam propriedades citotóxica, antitumorigênica e antiparasitária. Neste estudo, foram avaliados os possíveis efeitos mutagênico, antimutagênico e citotóxico do extrato etanólico de folhas de araticum, pelo teste de micronúcleos em camundongos. Para a investigação da atividade mutagênica, os animais foram tratados com o extrato etanólico de araticum (EEA) utilizando 10, 20, 50, 100 e 160 mg.kg-1. Para todas as doses, as freqüências de eritrócidos policromáticos micronucleados (MNPCE) foram avaliadas em 24, 48 e 72 horas após o tratamento. Para a investigação da atividade antimutagênica, os animais foram tratados com 10, 20, 50 e 100 mg.kg-1 de EEA simultaneamente com 4 mg.kg-1 de MMC. A freqüência de MNPCE foi avaliada após 36 horas de exposição. A citotoxicidade foi avaliada pela razão de eritrócitos policromáticos e normocromáticos (PCE/NCE). Na avaliação da mutagenicidade, todas as doses de EEA não aumentaram significativamente o número de MNPCE (P > 0,05), comparativamente as do grupo solvente-controle. Em relação ao tempo de administração, não foi constatada diferença significativa entre os 3 períodos avaliados (P > 0,05). Esses resultados indicam que o EEA não exerceu atividade mutagênica.A citotoxicidade foi evidente nas doses de 50, 100 e 160 mg.kg-1 em 24 e 48 horas depois da exposição. Em relação à antimutagenicidade, exceto para a dose de 10 mg.kg-1 co-administrada com 4 mg.kg-1 de MMC, todas reduziram significativamente a freqüência de MNPCE, comparativamente as do grupo controle positivo (P < 0,05). Esses resultados, portanto, indicam uma atividade antimutagênica do EEA. A citotoxicidade foi significativamente aumentada (P < 0,01) na dose de 100 mg.kg-1 de EEA co-administrada com 4 mg.kg-1 de MMC.

miRNApath: a database of miRNAs, target genes and metabolic pathways.

MicroRNAs (miRNAs) are small non-coding RNAs that regulate target gene expression and hence play important roles in metabolic pathways. Recent studies have evidenced the interrelation of miRNAs with cell proliferation, differentiation, development, and diseases. Since they are involved in gene regulation, they are intrinsically related to metabolic pathways. This leads to questions that are particularly interesting for investigating medical and laboratorial applications. We developed an miRNApath online database that uses miRNA target genes to link miRNAs to metabolic pathways. Currently, databases about miRNA target genes (DIANA miRGen), genomic maps (miRNAMap) and sequences (miRBase) do not provide such correlations. Additionally, miRNApath offers five search services and a download area. For each search, there is a specific type of input, which can be a list of target genes, miRNAs, or metabolic pathways, which results in different views, depending upon the input data, concerning relationships between the target genes, miRNAs and metabolic pathways. There are also internal links that lead to a deeper analysis and cross-links to other databases with more detailed information. miRNApath is being continually updated and is available at http://lgmb.fmrp.usp.br/mirnapath.

miRNApath: a database of miRNAs, target genes and metabolic pathways

MicroRNAs (miRNAs) are small non-coding RNAs that regulate target gene expression and hence play important roles in metabolic pathways. Recent studies have evidenced the interrelation of miRNAs with cell proliferation, differentiation, development, and diseases. Since they are involved in gene regulation, they are intrinsically related to metabolic pathways. This leads to questions that are particularly interesting for investigating medical and laboratorial applications. We developed an miRNApath online database that uses miRNA target genes to link miRNAs to metabolic pathways. Currently, databases about miRNA target genes (DIANA miRGen), genomic maps (miRNAMap) and sequences (miRBase) do not provide such correlations. Additionally, miRNApath offers five search services and a download area. For each search, there is a specific type of input, which can be a list of target genes, miRNAs, or metabolic pathways, which results in different views, depending upon the input data, concerning relationships between the target genes, miRNAs and metabolic pathways. There are also internal links that lead to a deeper analysis and cross-links to other databases with more detailed information. miRNApath is being continually updated and is available at http://lgmb.fmrp.usp.br/mirnapath.