MyoD converts primary dermal fibroblasts, chondroblasts, smooth muscle, and retinal pigmented epithelial cells into striated mononucleated myoblasts and multinucleated myotubes ( ABSTRACTShortly after their birth, postmitotic mononucleated myoblasts in myotomes, limb buds, and conventional muscle cultures elongate and assemble a cohort of myofibrillar proteins into definitively striated myofibrils. MyoD induces a number of immortalized and/or transformed nonmuscle cells to express desmin and several myofibrillar proteins and to fuse into myosacs. We now report that MyoD converts normal dermal fibroblasts, chondroblasts, gizzard smooth muscle, and pigmented retinal epithelial cells into elongated postmitotic mononucleated striated myoblasts. The sarcomeric localization of antibodies to desmin, a-actinin, titin, troponin-I, a-actin, myosin heavy chain, and myomesin in these converted myoblasts are indistinguishable from in vivo and in vitro normal myoblasts. Converted myoblasts fuse into typical anisodiametric multinucleated myotubes that often contract spontaneously. Conversion and subsequent expression of the skeletal myogenic program are autonomous events, occurring in four nonmuscle microenvironments consisting of different combinations of foreign extracellular matrix molecules. Early events associated with conversion by MyoD involve (i) withdrawal from the cell cycle, (ii) down-regulation of the subverted cell's ongoing differentiation program, and (iii) initiation of desmin synthesis in presumptive myoblasts and dramatic redistribution of microtubules and desmin intermediate filaments in postmitotic myoblasts.

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The regulation of the furosemide-sensitive Na+-ATPase activity and ouabain-sensitive (Na+ + K+)ATPase activities from proximal tubules by adenosine was investigated. When the concentration of adenosine was increased the furosemide-sensitive ATPase activity decreased with maximal inhibition at 10(-8) M (56% of inhibition). However, the (Na+ + K+)ATPase activity was not affected by adenosine. Theophylline, an antagonist of P1 adenosine receptor, completely reversed the effect of adenosine on the furosemide-sensitive ATPase activity in a dose-response manner. The adenosine effect was mimicked by N6-cyclohexyladenosine (CHA), an agonist for A1 adenosine receptor. 5'-N-ethylcarboxamideadenosine (NECA), an agonist for A2 adenosine receptor, did not affect the furosemide-sensitive ATPase activity. When adenosine was used in the presence of 1 microg ml(-1) pertussis toxin, a Gi protein inhibitor, no change in the furosemide-sensitive ATPase activity was observed. The addition of 1 nM cholera toxin increased the Na+-ATPase activity by 60%. Adenosine decreased the cholera toxin stimulated Na+-ATPase in 42%, similar to the effect observed in the absence of cholera toxin. Dibutyryl-cAMP reversed the effect of adenosine in a dose dependent manner while the protein kinase A peptide inhibitor mimicked it. These data are compatible with a modulatory effect of adenosine on the Na+-ATPase activity via A1 subtype receptor.

The Papanicolaou test, the most readily available cytologic method for screening sexually transmitted pathogens and cellular abnormalities in most developing countries, is inadequate for the diagnosis of trichomoniasis due to its inherent limitations. However, PCR is a highly sensitive and specific test for the diagnosis of trichomoniasis.

Cad. Saúde Colet., 2013, Rio de Janeiro, 21 (2): 209-23 209 RevisãoResumo A exposição a substâncias carcinogênicas é reconhecidamente maior nos ambientes de trabalho, e muitas destas foram assim classificadas a partir de estudos epidemiológicos realizados com populações trabalhadoras. O objetivo do estudo foi realizar uma revisão integrativa sobre os principais agentes carcinogênicos presentes no ambiente de trabalho, bem como as principais topografias acometidas por estas substâncias. Foi realizado levantamento nas bases de dados LILACS e MEDLI-NE, cujo termo de busca foi "occupational cancer" e "câncer ocupacional". Observou-se que os artigos apontam para o fato de ser provável que a exposição ambiental/ocupacional à agentes químicos de uma forma geral esteja contribuindo também para o adoecimento da população, sem que uma relação entre causa e efeito seja estabelecida. A difusão de substâncias químicas não ocorre exclusivamente através das conhecidas formas de poluição. Portanto, é de fundamental importância a construção de um sistema de vigilância destes agravos que cumpra dois objetivos principais: a identificação e controle de ambientes de trabalho onde existe potencial exposição à agentes carcinogênicos e a sistematização de informações necessárias à realização de estudos epidemiológicos de caráter exploratório ou analítico.Palavras-chave: câncer; saúde do trabalhador; saúde pública. AbstractExposure to carcinogenic substances is known in most work environments, and many of these were classified as from epidemiological studies on working populations. The objective of this study is an integrative review on the main carcinogens at work environment as well as the main topographies affected by these substances. Survey was conducted in the databases MEDLINE and LILACS, whose term has been "câncer ocupacional" and "occupational cancer". It was observed that the articles point to the fact that it is likely that exposure to environmental/occupational to chemicals in general is also contribute to the disease population, without any relationship between cause and effect is established. The diffusion of chemicals does not occur exclusively through the known forms of pollution. It is therefore of paramount importance to build a surveillance system that meets these injuries two main objectives: to identify and control work environments where there is potential exposure to carcinogenic agents and systematization of information necessary to conduct epidemiological studies, whether exploratory or analytical.

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