RESUMO
Cruciferous vegetables and citrus fruits are reported to possess health-beneficial properties, but also have been shown to contain natural aryl hydrocarbon receptor (AhR) agonists (NAhRAs). Binding to the AhR is widely assumed to activate the main pathway by which dioxins, like 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) exert their toxicity. To establish whether or not activation of the AhR pathway by NAhRAs and dioxin-like substances results in similar cellular responses, gene expression profiles induced in Caco-2 cells were studied using microarray analysis. Cells were exposed to indolo[3,2-b]carbazole (ICZ), an acid reaction product from cruciferous vegetables, and to extracts of citrus pulp and grapefruit juice. Gene expression profiles induced by these NAhRAs were compared to those of the xenobiotic AhR agonists TCDD and benzo[a]pyrene (B[a]P). Over 20 genes were found more than 1.5 times up- or down-regulated by TCDD, and the expression of most of these genes was modulated in the same direction and to a similar extent by B[a]P and the NAhRAs. Results were confirmed by RT-PCR, and many of these genes may be involved in dioxin-related toxic effects. In conclusion, this in vitro study showed similar effects induced by NAhRAs, TCDD and B[a]P at the transcriptome level in a human intestinal cell line.
Assuntos
Benzo(a)pireno/toxicidade , Citrus/química , Poluentes Ambientais/toxicidade , Perfilação da Expressão Gênica , Dibenzodioxinas Policloradas/toxicidade , Receptores de Hidrocarboneto Arílico/agonistas , Verduras/química , Células CACO-2 , Cromatografia Líquida de Alta Pressão , Citocromo P-450 CYP1A1/metabolismo , DNA Complementar/biossíntese , DNA Complementar/genética , Expressão Gênica/efeitos dos fármacos , Genes Reporter , Humanos , Luciferases/genética , Análise de Sequência com Séries de Oligonucleotídeos , Extratos Vegetais/química , RNA/biossíntese , RNA/genética , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Xenobióticos/toxicidadeRESUMO
To identify epidemiological features of culture-proven campylobacter infections and to determine resistance rates, we conducted a 4-year demographic survey of culture-proven campylobacteriosis in one Dutch region. Examination of 24,435 fecal specimens revealed 1,315 cases of campylobacteriosis (5.4%). The ofloxacin-resistance rate among Campylobacter isolates increased from 11% to 29%. Resistance against tetracycline fluctuated between 7% and 15%, and resistance against erythromycin remained low. Resistance against fluoroquinolones was seasonally influenced, with relatively high rates during winter. We conclude that resistance of Campylobacter isolates to fluoroquinolones is still rising, probably because of the use of fluoroquinolones (enrofloxacin) in animal husbandry.
