Intervertebral disc (IVD) degeneration often leads to low back pain, which is one of the major causes of disability worldwide, affecting more than 80% of the population. Although available treatments for degenerated IVD decrease symptoms' progression, they fail to address the underlying causes and to restore native IVD properties. Poly(γ-glutamic acid) (γ-PGA) has recently been shown to support the production of chondrogenic matrix by mesenchymal stem/stromal cells. γ-PGA/chitosan (Ch) nanocomplexes (NCs) have been proposed for several biomedical applications, showing advantages compared with either polymer alone. Hence, this study explores the potential of γ-PGA and γ-PGA/Ch NCs for IVD regeneration. Nucleotomised bovine IVDs were cultured ex vivo upon injection of γ-PGA (pH 7.4) and γ-PGA/Ch NCs (pH 5.0 and pH 7.4). Tissue metabolic activity and nucleus pulposus DNA content were significantly reduced when NCs were injected in acidic-buffered solution (pH 5.0). However, at pH 7.4, both γ-PGA and NCs promoted sulphated glycosaminoglycan production and significant type II collagen synthesis, as determined at the protein level. This study is a first proof of concept that γ-PGA and γ-PGA/Ch NCs promote recovery of IVD native matrix, opening new perspectives on the development of alternative therapeutic approaches for IVD degeneration.
O artigo examina o pensamento político de Roberto Campos entre meados das décadas de 1950 e 1970. Neste período, além de importantes funções governamentais, Campos dedicou-se intensamente à luta de idéias, publicando grande quantidade de artigos e ensaios. Será desenvolvida a hipótese de que o seu pensamento político aponta para a institucionalização de um sistema político de tipo autoritário como o mais adequado às condições culturais e políticas da sociedade brasileira. A principal característica deste tipo de sistema consiste na hipertrofia do poder Executivo estatal, sob comando de militares e tecnocratas, relativamente aos demais poderes da República. A função primordial do poder Executivo hipertrofiado são a elaboração e a implementação de reformas institucionais e de políticas econômicas "racionais", contra as resistências pretensamente particularistas e irracionais dos diferentes setores da sociedade brasileira. Essa hipótese colide frontalmente com a sugestão de Campos de que o regime instituído após o movimento de 1964 seria uma espécie de atualização, nas condições da sociedade brasileira de então, do instituto da "ditadura comissária" da antiga República romana, pelo qual se permitia a eleição de um ditador por um curto período de tempo para debelar eventuais ameaças às instituições republicanas.
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