The current state of play of research on the social, political and legal dimensions of HIV / O estado atual da pesquisa sobre as dimensões sociais, políticas e legais do HIV / Estado actual de la investigación sobre las dimensiones sociales, políticas y legales del VIH

This paper offers a critical overview of social science research presented at the 2014 International AIDS Conference in Melbourne, Australia. In an era of major biomedical advance, the political nature of HIV remains of fundamental importance. No new development can be rolled out successfully without taking into account its social and political context, and consequences. Four main themes ran throughout the conference track on social and political research, law, policy and human rights: first, the importance of work with socially vulnerable groups, now increasingly referred to as "key populations"; second, continued recognition that actions and programs need to be tailored locally and contextually; third, the need for an urgent response to a rapidly growing epidemic of HIV among young people; and fourth, the negative effects of the growing criminalization of minority sexualities and people living with HIV. Lack of stress on human rights and community participation is resulting in poorer policy globally. A new research agenda is needed to respond to these challenges.

Este artigo oferece uma perspectiva crítica da pesquisa em ciências sociais apresentada na Confe-rência Internacional de AIDS de Melbourne, Aus-trália, em 2014. Em tempos de grandes avanços no campo biomédico, a natureza política do HIV permanece de importância fundamental. Nenhuma inovação será bem-sucedida na prática se desconsiderar o contexto sociopolítico e suas consequências. Quatro temas emergiram da Conferência nos campos do direito, dos direitos humanos e da pesquisa social e política: (1) a importância do trabalho com grupos socialmente vulneráveis, crescentemente chamado de "populações chaves"; (2) o reconhecimento de que ações e programas devem ser sob medida para cada local e contexto; (3) a urgência da resposta a uma epidemia crescendo muito rapidamente entre adolescentes; (4) o efeito negativo da crescente criminalização de minorias sexuais e pessoas vivendo com HIV. Globalmente, a falta de ênfase nos direitos humanos e da participação comunitária tem como resultado políticas públicas de pior qualidade. Precisamos de uma nova agenda de pesquisa para responder a esses desafios.

El artículo ofrece una perspectiva crítica de la investigación en ciencias sociales, presentada en la Conferencia Internacional de SIDA en Melbourne (Australia), 2014. En tiempos de enormes avances biomédicos, la naturaleza política del VIH sigue siendo muy importante. Ninguna innovación será exitosa sin considerar el contexto sociopolítico y sus consecuencias. Cuatro temas surgieron de la conferencia en el campo legal y derechos humanos, además de investigación social y política: (1) la importancia del trabajo con grupos socialmente vulnerables, crecientemente denominados "poblaciones claves"; (2) el reconocimiento de que las acciones y programas deben ser adaptados a un contexto local; (3) la urgencia de una respuesta a una epidemia con crecimiento rápido entre adolescentes; (4) el efecto negativo de la creciente criminalización de las minorías sexuales y personas viviendo con VIH. Globalmente, un limitado énfasis en los derechos humanos y la participación comunitaria tiene como consecuencia peores políticas públicas. Necesitamos una nueva agenda de investigación para responder a estos desafíos.

Roles and causes of abnormal DNA methylation in gastrointestinal cancers.

Evidence now suggests that epigenetic abnormalities, particularly altered DNA methylation, play a crucial role in the development and progression of human gastrointestinal malignancies. Two distinct DNA methylation abnormalities are observed together in cancer. One is an overall genome-wide reduction in DNA methylation (global hypomethylation) and the other is regional hypermethylation within the CpG islands of specific gene promoters. Global hypomethylation is believed to induce proto-oncogene activation and chromosomal instability, whereas regional hypermethylation is strongly associated with transcriptional silencing of tumor suppressor genes. To date, genes involved in regulation of the cell cycle, DNA repair, growth signaling, angiogenesis, and apoptosis, are all known to be inactivated by hypermethylation. Recently developed techniques for detecting changes in DNA methylation have dramatically enhanced our understanding of the patterns of methylation that occur as cancers progress. One of the key contributors to aberrant methylation is aging, but other patterns of methylation are cancer-specific and detected only in a subset of tumors exhibiting the CpG island methylator phenotype (CIMP). Although the cause of altered patterns of DNA methylation in cancer remains unknown, it is believed that epidemiological factors, notably dietary folate intake, might strongly influence DNA methylation patterns. Recent studies further suggest that polymorphisms of genes involved in folate metabolism are causally related to the development of cancer. Identifying epidemiological factors responsible for epigenetic changes should provide clues for cancer prevention in the future.

The prima donna of epigenetics: the regulation of gene expression by DNA methylation

This review focuses on the mechanisms of DNA methylation, DNA methylation pattern formation and their involvement in gene regulation. Association of DNA methylation with imprinting, embryonic development and human diseases is discussed. Furthermore, besides considering changes in DNA methylation as mechanisms of disease, the role of epigenetics in general and DNA methylation in particular in transgenerational carcinogenesis, in memory formation and behavior establishment are brought about as mechanisms based on the cellular memory of gene expression patterns.

RNA interference: a novel and physiologic mechanism of gene silencing with great therapeutic potential

The post-genomics scientific era has evolved rapidly while achieving advanced understanding of the structure and function of the genes responsible for both the phenotypic characteristics of higher organisms and the pathophysiology of several genetic diseases. Researchers in the fields of oncology and infectious diseases have become more convinced of the great potential of molecular biology approaches to further develop highly specific diagnostic and less toxic therapeutic strategies. During the last two decades, approaches for the specific silencing of essential viral genes and cellular oncogenes were evaluated with optimism for developing directed therapies. However, there were drawbacks in the use of antisense oligonucleotides as a practical mechanism of achieving gene silencing both in vitro and in vivo. Recently, a novel role for post-transcriptional gene silencing mediated by double-stranded RNA (dsRNA) was discovered in the experimental model of C. elegans. This mechanism, termed RNA interference (RNAi) has also been found in other eukaryotes, from plants to mammals, including humans. RNAi is presently being explored both in vitro and in vivo in functional genomics studies and possible therapeutic uses due to its highly specific and physiologic mode of gene silencing. This article focuses on the most current information available regarding the RNAi mechanism and its uses in models of cancer and infectious diseases.

Silenciamento de genes com RNA interferência: um novo instrumento para investigação da fisiologia e fisiopatologia do córtex adrenal / Gene silencing with RNA interference: a novel tool for the study of physiology and pathophysiology of adrenal cortex

A inativação de genes por knock-out ou por bloqueio da tradução de seus transcritos (silenciamento) constitui uma estratégia extremamente poderosa tanto para atribuir função aos genes como para mapear a inter-relação dos diferentes componentes das vias regulatórias intracelulares. Um dos meios para se obter o silenciamento pós-transcricional consiste na ativação de um mecanismo mediado por RNAs fita-dupla (dsRNA) conhecido como RNA interferência (RNAi). O RNAi se mostrou um instrumento extremamente versátil em pesquisa biomédica, podendo ser utilizado em experimentos de silenciamento pontual de genes ou ser adaptado para estudos em larga escala de genômica funcional, podendo, inclusive, ser utilizado como meio de terapia gênica. Neste trabalho, os autores discutem as vias intracelulares envolvidas no RNAi, bem como as principais estratégias e limitações técnicas para se obter o silenciamento em células de mamíferos. Fazem, também, uma revisão das principais aplicações do RNAi na terapêutica de doenças humanas e na investigação de fenômenos fisiológicos e fisiopatológicos do córtex adrenal.

5' CpG island methylation of p16 is associated with absence of p16 expression in glioblastomas

Recent evidence shows that transcriptional silencing as a consequence of hypermethylation of CpG islands is an important mechanism in the inactivation of p16INK4 tumor suppressor gene. This study is designed to clarify the significance of p16INK4 hypermethylation in 23 cases of glioblastomas (GBMs) by methylation-specific polymerase chain reaction (PCR) and p16 immunostaining. Fourteen cases (60.9%) out of 23 GBMs revealed hypermethylation on p16. p16 immunostaining revealed that 13 (93%) of these 14 hypermethylation cases showed complete loss of immunoreactivity and only one (7%) case retained immunoreactivity. Among 9 methylation-negative cases, 4 were immunonegative, which might be related to mutations or deletions other than hypermethylation. The most significant finding was that of 17 cases with immunonegativity, 13 cases (76.5%) showed hypermethylation. We reconfirmed that p16 hypermethylation may be one of the major mechanisms of tumorigenesis of GBMs and the results between the methylation specific-PCR study and p16 immunostaining had a good correlation.