H. Moreau

The gastrointestinal tract is considered to be a major route of infection for human immunodeficiency virus (HIV). Infection of human colon epithelial cells by HIV is not blocked by anti-CD4 antibodies known to block infection of lymphoid cells (J. Fantini, N. Yahi, and J. C. Chermann, Proc. Natl. Acad. Sci. USA 88:9297-9301, 1991), suggesting the presence of an alternate receptor for HIV on these cells. In this report, we show that (i) a monoclonal antibody specifically directed against galactosyl ceramide inhibited the infection of HT29 cells by two markedly different strains of HIV-1, as assessed by polymerase chain reaction amplification and reverse transcriptase assay; (ii) this antibody strongly labeled the surface of HT29 cells by immunofluorescence and electron microscopic immunolocalization; (iii) the labeling was preferentially but not totally restricted to the basolateral membrane domain of differentiated colonic cells, in agreement with the ability of HIV to infect both the apical and basolateral surfaces of these epithelial cells; and (iv) in thin-layer chromatography-immunostaining experiments with neutral glycolipids prepared from HT29 cells, the antibody specifically reacted with a ceramide monoglycoside fraction corresponding to galactosyl ceramide. We did not detect this glycolipid in lymphoid cells, and anti-galactosyl ceramide antibodies consistently failed to inhibit HIV infection of these cells. These data suggest that galactosyl ceramide (or a derivative) is an essential component of the receptor for HIV on the surface of HT29 cells.

In the immune system, mCD24, the mouse homolog of the human glycosyl phosphatidylinositol-anchored glycoprotein CD24, may play a role in cell adhesion. In the nervous system, the function of mCD24 has not been determined, but its transient expression by neurons suggests that it may be involved in axon growth in development. Here we show that retinal ganglion cells (RGCs) and dorsal root ganglion (DRG) neurons express mCD24 in the developing but not adult mouse in vivo and in DRG neurons of the injured adult peripheral nervous system (PNS). In vitro, mCD24 was expressed by immature neurons and by a subpopulation of adult DRG neurons. To analyze the possible function of mCD24 in the nervous system, we prepared rat C6 glioma cells stably transfected or retrovirally infected with mCD24 cDNA. The cells did not exhibit changes in their adhesive properties or cell division rate after transfection or infection. When mCD24-expressing cells were used as monolayer substrates for culturing RGCs and DRG neurons, neurite outgrowth was inhibited, depending on neuronal age and on the relative levels of mCD24 in the monolayer. This inhibition, however, was not dependent on the expression of mCD24 by the neurons themselves, because DRG neurons of a mouse deleted of the mCD24 gene showed the same response. These results show that mCD24 interacts in a heterophilic manner with a developmentally regulated molecule expressed by neurons, and they suggest that in vivo, mCD24 may inhibit the further extension or collateral branching of axons in late embryonic development.

O objetivo desse artigo foi demonstrar a gênese e função da apologia indireta ao capitalismo na assim chamada “doutrina gerencialista” ou teoria dos gestores na qual estes seriam uma nova e dominante classe social na suposta transição do modo de produção capitalista para uma “sociedade gerencial”. Essa doutrina ou teoria não é nova. Surgida a partir de uma série de desenvolvimentos na transição entre os séculos XIX e XX, ganhou fôlego com Bruno Rizzi e James Burnham nas décadas de 1930 e 1940, sendo o segundo autor uma fonte primária de grande difusão a partir do livro A Revolução Gerencial. Um segundo desenvolvimento teve impulso com J.K. Galbraith a partir dos anos de 1960, obtendo considerável difusão, inclusive no Brasil, por mediação de intelectuais como Bresser Pereira. Sabemos que como todas as formações de pensamento, a ideologia dos gestores está ligada a condições sócio-históricas e é nos EUA que reuniram-se as condições necessárias e suficientes em mais alto grau para o desenvolvimento de tal teoria dos gestores.