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1.
Semina cienc. biol. saude ; 32(1): 15-28, jan.-jun. 2011.
Artigo em Português | LILACS | ID: lil-673003

RESUMO

Candida albicans pode causar graves infecções em pacientes que estão imunocomprometidos por doenças, por cirurgias ou por terapia imunossupressiva. Os altos níveis de morbidade e mortalidade resultantes de infecções em pacientes hospitalizados mostraram que C. albicans tornou-se um patógeno humano de grande relevância clínica. Mesmo o sistema imune sendo o principal fator que define a transição do fungo de comensal para patogênico, fatores de virulência expressos por C. albicans, tais como adesinas, mudança fenotípica, comportamento dimórfico, e secreção de enzimas hidrolíticas, podem contribuir para a persistência da colonização, assim como o desenvolvimento de episódios sintomáticos. A defesa do hospedeiro compreende ingestão e eliminação do fungo por células fagocíticas que possuem vários receptores, como o Toll-4, dectina-1 associado a receptores tipo Toll-2 e receptores de manose. A interleucina-10 (IL-10) produzida por fagócitos determina a susceptibilidade do hospedeiro a infecção fúngica, enquanto a IL-10 produzida por células T reguladoras é responsável pelo comensalismo. Em contraste, a produção de fator de necrose tumoral- α (TNF-α), interleucina –1 β (lL-1 β), (IL-6), (Il-12) e IL-17 conferem imunidade protetora. O interferon-γ (IFN- γ) produzido por células natural “killer” e células Th1 estimula a migração de fagócitos e maior eficácia na destruição do fungo. Nas células epiteliais de mucosas os receptores NOD-like e defensinas-β citoplasmáticos evitam a translocação de C. albicans da microbiota para os tecidos os quais são modulados por citocinas IL-1 β,IL-17 e IL-22.


Candida albicans can cause grave infections in patients who are immunocompromised by diseases, by surgery, or by immunesupresive therapy. The high levels of morbidity and mortality resulting from those infections in hospitalized patients show that C. albicans became a prominent human pathogen. Although the host immune system is the major factor balancing the transition from commensalisms to pathogenicity, several virulence attributes expressed by C. albicans, such as adhesion factors, phenotypic switching, dimorphic behavior, and secretion of hydrolytic enzymes, might contribute to the persistence of colonization as well as the development of symptomatic episodes. Host defense against candidiasis relies mainly on the ingestion and elimination of C. albicans by phagocytic cells, which present receptors Toll-like 4, dectin–1 associated to receptors Toll-like2 and mannose receptors. The cytokine IL-10 (IL-10) produced by phagocytes has a crucial role on susceptibility of host fungal infection, whereas IL-10 produced by regulatory T cells is mainly responsible by commensalisms. In contrast, productions of tumour necrosis factor - α (TNF-α), interleukin–1 β (lL-1 β), (IL-6) and (Il-12) provided protective cell–mediated immunity. The interferon-γ produced by natural killer and TH1 cells stimulates migration of phagocytes and major efficacy on destruction of fungi. In epithelial cells from mucosas the NOD-like receptors and defensins-β cytoplasmatic prevent the translocation of C. albicans from microbiota to tissues, which are modulated by IL-1 β, Il-17 and Il-22 cytokines.


Assuntos
Candida albicans , Células Th1
2.
Appl. cancer res ; 29(4): 150-156, Oct.-Dec. 2009.
Artigo em Inglês | LILACS, Inca | ID: lil-547646

RESUMO

Objective: This revision characterizes the biomarkers used for analysis of the development of oxidative stress produced during breast cancer chemotherapy. Materials and methods: A search of articles indexed in digital databases (Lilacs, Bireme, PubMed, Scielo and digital libraries), along with publications printed as books, periodicals and articles not available online, in the period from 1979 to 2009. Conclusion: Reactive oxygen and nitrogen species are produced, principally, during aerobic metabolism; however, its synthesis can be exacerbated or antioxidant defense reduced or more usually, both conditions can occurr in many pathophysiologic situations, leading to a net reactive species yelded. This unbalance is defined as oxidative stress. Stress biomarkers can be defined as predictive indicators able to detect in vivo oxidative damage and can be subdivided into antioxidant and pro-oxidants. To verify the antioxidant system, it is possible to analyze the superoxide dismutase enzymes, catalase and glutathione, along with vitamins A, E, C and glutathione among others. The analysis of pro-oxidants can be made through the verification of protein nitration and oxidation, heat shock proteins, lipoperoxidation, formation of aldehydes for malondialdehyde tests, 4-hydroxynonenal, oxidized LDL and isoprostanes or for chemiluminescent techniques. Advances in cancer detection through the identification of potential biomarkers consist of a promising strategy for the prevention and early identification of this pathology.


Assuntos
Humanos , Antioxidantes , Biomarcadores Farmacológicos , Neoplasias da Mama , Radicais Livres , Neoplasias , Estresse Oxidativo , Catalase , Tratamento Farmacológico , Glutationa , Literatura de Revisão como Assunto
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