RESUMO
Hepatitis C virus-associated chronic hepatitis is one of the most important causes of liver-related mortality and morbidity worldwide. This review analysis the available clinical and epidemiological information about this disease in Chile and compares it with data available from Latin America and other countries. Chronic hepatitis C seroprevalence in the general Chilean population is 1.15% by ELISA III and 0.85% by recombinant immunoblot assay (RIBA). Mortality due to cirrhosis (all causes) in Chile is one of the highest in the world. We show indirect evidence that chronic hepatitis C may account for a significant proportion of these deaths. The disease is the most common cause for liver transplantation in adults. Based on the available information, we conclude that chronic hepatitis C is an important cause of disease and mortality in Chile.
Assuntos
Adulto , Idoso , Humanos , Pessoa de Meia-Idade , Hepatite C Crônica/epidemiologia , Distribuição por Idade , Carcinoma Hepatocelular/epidemiologia , Carcinoma Hepatocelular/mortalidade , Chile/epidemiologia , Ensaio de Imunoadsorção Enzimática/métodos , Hepatite C Crônica/mortalidade , América Latina/epidemiologia , Cirrose Hepática/epidemiologia , Cirrose Hepática/mortalidade , Neoplasias Hepáticas/epidemiologia , Neoplasias Hepáticas/mortalidade , Transplante de Fígado , RNA Viral/sangue , Fatores de Risco , Estudos SoroepidemiológicosRESUMO
Ribosome recruitment to eukaryotic mRNAs is generally thought to occur by a scanning mechanism, whereby the 40S ribosomal subunit binds in the vicinity of the 5'cap structure of the mRNA and scans until an AUG codon is encountered in an appropriate sequence context. Study of the picornaviruses allowed the characterization of an alternative mechanism of translation initiation. Picornaviruses can initiate translation via an internal ribosome entry segment (IRES), an RNA structure that directly recruits the 40S ribosomal subunits in a cap and 5' end independent fashion. Since its discovery, the notion of IRESs has extended to a number of different virus families and cellular RNAs. This review summarizes features of both cap-dependent and IRES-dependent mechanisms of translation initiation and discusses the role of cis-acting elements, which include the 5'cap, the 5'-untranslated region (UTR) and the poly(A) tail as well as the possible roles of IRESs as part of a cellular stress response mechanism and in the virus replication cycle.