CD40 and dendritic cell function

CD40 has emerged as a key signaling pathway for the function of B cells, monocytes, and dendritic cells (DC) in the immune system, and plays a major role in inflammatory pathways of nonhemopoletic cells. CD40 is expressed by monocytes and DC and is up-regulated when DC migrate from the periphery to draining lymph nodes (DLN) in response to microbial challenge. CD154 signaling by MHC-restricted, activated CD4* T cells induces differentiation of DC, as defined by an increased surface expression of MHC, costimulatory, and adhesion molecules. Thus, CD40 functions in the adaptive immune response as a trigger for the expression of costimulatory molecules for efficient T-cell activation. CD40 ligation of DC also has the capacity to induce high levels of the cytokine IL-12, which polarizes CD4(+) T cells toward a T helper 1 (Th1) type, enhances proliferation of CD8(+) T cells, and activates NK cells. CD40 may also play an important role in the decision between tolerance and immunity and the generation of regulatory CD4(+) T cells that are thought to maintain peripheral self-tolerance in vivo.

Direct electrochemistry of a bacterial sulfite dehydrogenase

Sulfite dehydrogenase from Starkeya novella is an alphabeta heterodimer comprising a 40.6 kDa subunit (containing the Mo cofactor) and a smaller 8.8 kDa heme c subunit. The enzyme catalyses the oxidation of sulfite to sulfate with the natural electron acceptor being cytochrome c(550). Its catalytic mechanism is thought to resemble that found in eukaryotic sulfite oxiclases. Using protein film voltammetry and redox potentiometry, we have identified both Mo- and heme-centered redox responses from the enzyme immobilized on a pyrolytic graphite working electrode: E-m,E-8 (Fe-III/II) +177 mV; E-m,E-8 (Mo-VI/V) +211 mV and E(m,)8 (Mo-V/IV) -118 mV vs NHE; Upon addition of sulfite to the electrochemical cell a steady-state voltammogram is observed and an apparent Michaelis constant (K-m) of 26(l) muM was determined for the enzyme immobilized on the working electrode surface, which is comparable with the value obtained from solution assays.

Alternatively spliced products of the human kinesin light chain 1 (KNS2) gene

Conventional kinesin is a microtubule-based molecular motor involved in the transport of membranous and non-membranous cargoes. The kinesin holoenzyme exists as a heterotetramer, consisting of two heavy chain and two light chain subunits. It is thought that one function of the light chains is to interact with the cargo. Alternative splicing of kinesin light chain pre-mRNA has been observed in lower organisms, although evidence for alternative splicing of the human gene has not been reported. We have identified 19 variants of the human KNS2 gene (KLC1) that are generated by alternative splicing of downstream exons, but calculate that KNS2 has the potential to produce 285919 spliceforms. Corresponding spliceforms of the mouse KLC1 gene were also identified. The alternative exons are all located 3' of exon 12 and the novel spliceforms produce both alternative carboxy termini and alternative 3' untranslated regions. The observation of multiple light chain isoforms is consistent with their proposed role in specific cargo attachment.

Primary aldosteronism

Approaching the fiftieth year since its original description, primary aldosteronism is now thought to be the commonest potentially curable and specifically treatable form of hypertension. Correct identification of patients with primary aldosteronism requires that the effects of time of day, posture, dietary sodium intake, potassium levels and medications on levels of aldosterone and renin be carefully considered. Accurate elucidation of the subtype is essential for optimal treatment, and adrenal venous sampling is the only reliable means of differentiating aldosterone-producing adenoma from bilateral adrenal hyperplasia. With genetic testing already available for one inherited form, making more cumbersome biochemical testing for that subtype virtually obsolete and bringing about improvements in treatment approach, an intense search is underway for genetic mutations causing other, more common familial varieties of primary aldosteronism.

Alterations of neocortical pyramidal cell phenotype in the Ts65Dn mouse model of Down syndrome: Effects of environmental enrichment

Mental retardation in individuals with Down syndrome (DS) is thought to result from anomalous development and function of the brain; however, the underlying neuropathological processes have yet to be determined. Early implementation of special care programs result in limited, and temporary, cognitive improvements in DS individuals. In the present study, we investigated the possible neural correlates of these limited improvements. More specifically, we studied cortical pyramidal cells in the frontal cortex of Ts65Dn mice, a partial trisomy of murine chromosome 16 (MMU16) model characterized by cognitive deficits, hyperactivity, behavioral disruption and reduced attention levels similar to those observed in DS, and their control littermates. Animals were raised either in a standard or in an enriched environment. Environmental enrichment had a marked effect on pyramidal cell structure in control animals. Pyramidal cells in environmentally enriched control animals were significantly more branched and more spinous than non-enriched controls. However, environmental enrichment had little effect on pyramidal cell structure in Ts65Dn mice. As each dendritic spine receives at least one excitatory input, differences in the number of spines found in the dendritic arbors of pyramidal cells in the two groups reflect differences in the number of excitatory inputs they receive and, consequently, complexity in cortical circuitry. The present results suggest that behavioral deficits demonstrated in the Ts65Dn model could be attributed to abnormal circuit development.

Parvalbumin-, calbindin-, and calretinin-immunoreactive neurons in the prefrontal cortex of the owl monkey (Aotus trivirgatus): A standardized quantitative comparison with sensory and motor areas

Recent studies have revealed regional variation in the density and distribution of inhibitory neurons in different cortical areas, which are thought to reflect area-specific specializations in cortical circuitry. However, there are as yet few standardized quantitative data regarding how the inhibitory circuitry in prefrontal cortex (PFC), which is thought to be involved in executive functions such as cognition, emotion and decision making, compares to that in other cortical areas. Here we used immunohistochemical techniques to determine the density and distribution of parvalbumin (PV)-, calbindin (CB)-, and calretinin (CR)-immunoreactive (ir) neurons and axon terminals in the dorsolateral and orbital PFC of the owl monkey (Aotus trivirgatus), and compared them directly with data obtained using the same techniques in 11 different visual, somatosensory and motor areas. We found marked differences in the density of PV-ir, CB-ir, and CR-ir interneurons in several cortical areas. One hundred and twenty eight of all 234 possible between-area pairwise comparisons were significantly different. The density of specific subpopulations of these cells also varied among cortical areas, as did the density of axon terminals. Comparison of PFC with other cortical areas revealed that 40 of all 66 possible statistical comparisons of the density of PV-ir, CB-ir, and CR-ir cells were significantly different. We also found evidence for heterogeneity in the pattern of labeling of PV-ir, CB-ir, and CR-ir cells and axon terminals between the dorsolateral and orbital subdivisions of PFC. These data are likely to reflect basic differences in interneuron circuitry, which are likely to influence inhibitory function in the cortex. Copyright (C) 2003 S. Karger AG, Basel.

Dendritic branching of pyramidal cells in the visual cortex of the nocturnal owl monkey: A fractal analysis

The branching structure of neurones is thought to influence patterns of connectivity and how inputs are integrated within the arbor. Recent studies have revealed a remarkable degree of variation in the branching structure of pyramidal cells in the cerebral cortex of diurnal primates, suggesting regional specialization in neuronal function. Such specialization in pyramidal cell structure may be important for various aspects of visual function, such as object recognition and color processing. To better understand the functional role of regional variation in the pyramidal cell phenotype in visual processing, we determined the complexity of the dendritic branching pattern of pyramidal cells in visual cortex of the nocturnal New World owl monkey. We used the fractal dilation method to quantify the branching structure of pyramidal cells in the primary visual area (V1), the second visual area (V2) and the caudal and rostral subdivisions of inferotemporal cortex (ITc and ITr, respectively), which are often associated with color processing. We found that, as in diurnal monkeys, there was a trend for cells of increasing fractal dimension with progression through these cortical areas. The increasing complexity paralleled a trend for increasing symmetry. That we found a similar trend in both diurnal and nocturnal monkeys suggests that it was a feature of a common anthropoid ancestor.

Identification of cholinoceptive glycinergic neurons in the mammalian retina

The light-evoked release of acetylcholine (ACh) affects the responses of many retinal ganglion cells, in part via nicotinic acetylcholine receptors (nAChRs). nAChRs that contain beta2alpha3 neuronal nicotinic acetylcholine receptors have been identified and localized in the rabbit retina; these nAChRs are recognized by the monoclonal antibody mAb210. We have examined the expression of beta2alpha3 nAChRs by glycinergic amacrine cells in the rabbit retina and have identified different subpopulations of nicotinic cholinoceptive glycinergic cells using double and triple immunohistochemistry with quantitative analysis. Here we demonstrate that about 70% of the cholinoceptive amacrine cells in rabbit retina are glycinergic cells. At least three nonoverlapping subpopulations of mAb210 glycine-immunoreactive cells can be distinguished with antibodies against calretinin, calbindin, and gamma-aminobutyric acid (GABA)(A) receptors. The cholinergic cells in rabbit retina are thought to synapse only on other cholinergic cells and ganglion cells. Thus, the expression of beta2alpha3 nAChRs on diverse populations of glycinergic cells is puzzling. To explore this finding, the subcellular localization of beta2alpha3 was studied at the electron microscopic level. mAb210 immunoreactivity was localized on the dendrites of amacrines and ganglion cells throughout the inner plexiform layer, and much of the labeling was not associated with recognizable synapses. Thus, our findings indicate that ACh in the mammalian retina may modulate glycinergic circuits via extrasynaptic beta2alpha3 nAChRs. (C) 2002 Wiley-Liss, Inc.

A review of drainage and spontaneous rupture in free standing thin films with tangentially immobile interfaces

A review of spontaneous rupture in thin films with tangentially immobile interfaces is presented that emphasizes the theoretical developments of film drainage and corrugation growth through the linearization of lubrication theory in a cylindrical geometry. Spontaneous rupture occurs when corrugations from adjacent interfaces become unstable and grow to a critical thickness. A corrugated interface is composed of a number of waveforms and each waveform becomes unstable at a unique transition thickness. The onset of instability occurs at the maximum transition thickness, and it is shown that only upper and lower bounds of this thickness can be predicted from linear stability analysis. The upper bound is equivalent to the Freakel criterion and is obtained from the zeroth order approximation of the H-3 term in the evolution equation. This criterion is determined solely by the film radius, interfacial tension and Hamaker constant. The lower bound is obtained from the first order approximation of the H-3 term in the evolution equation and is dependent on the film thinning velocity A semi-empirical equation, referred to as the MTR equation, is obtained by combining the drainage theory of Manev et al. [J. Dispersion Sci. Technol., 18 (1997) 769] and the experimental measurements of Radoev et al. [J. Colloid Interface Sci. 95 (1983) 254] and is shown to provide accurate predictions of film thinning velocity near the critical thickness of rupture. The MTR equation permits the prediction of the lower bound of the maximum transition thickness based entirely on film radius, Plateau border radius, interfacial tension, temperature and Hamaker constant. The MTR equation extrapolates to Reynolds equation under conditions when the Plateau border pressure is small, which provides a lower bound for the maximum transition thickness that is equivalent to the criterion of Gumerman and Homsy [Chem. Eng. Commun. 2 (1975) 27]. The relative accuracy of either bound is thought to be dependent on the amplitude of the hydrodynamic corrugations, and a semiempirical correlation is also obtained that permits the amplitude to be calculated as a function of the upper and lower bound of the maximum transition thickness. The relationship between the evolving theoretical developments is demonstrated by three film thickness master curves, which reduce to simple analytical expressions under limiting conditions when the drainage pressure drop is controlled by either the Plateau border capillary pressure or the van der Waals disjoining pressure. The master curves simplify solution of the various theoretical predictions enormously over the entire range of the linear approximation. Finally, it is shown that when the Frenkel criterion is used to assess film stability, recent studies reach conclusions that are contrary to the relevance of spontaneous rupture as a cell-opening mechanism in foams. (C) 2003 Elsevier Science B.V. All rights reserved.

Purification of post-translationally modified proteins from bacteria: homologous expression and purification of histidine-tagged pilin from Neisseria meningitidis

Until recently, glycosylation of proteins in prokaryotes was regarded as uncommon and thought to be limited to special cases such as S-layer proteins and some archeal outer membrane proteins. Now, there are an increasing number of reports of bacterial proteins that are glycosylated. Pilin of pathogenic Neisseria is one of the best characterised post-translation ally modified bacterial proteins, with four different types of modifications reported, including a novel glycosylation. Pilin monomers assemble to form pilus fibres, which are long protein filaments that protrude from the surface of bacterial cells and are key virulence factors. To aid in the investigation of these modifications, pure pilin is required. A number of pilin purification methods have been published, but none are appropriate for the routine purification of pilin from many different isolates. This study describes a novel, rapid, and simple method of pilin purification from Neisseria meningitidis C311#3, which facilitates the production of consistent quantities of pure, native pilin. A 6 x histidine tag was fused to the C-terminus of the pilin subunit structural gene, pilE, via homologous recombination placing the 6 x histidine-tagged allele in the chromosome of N. meningitidis C311#3. Pilin was purified under non-denaturing conditions via a two-step process using immobilised metal affinity chromatography (IMAC), followed by dye affinity chromatography. Analysis of the purified pilin confirmed that it retained both of the post-translational modifications examined. This novel approach may prove to be a generally applicable method for purification and analysis of post-translationally modified proteins in bacteria. (C) 2003 Elsevier Science (USA). All rights reserved.

Say, Sismondi e o debate continental sobre os mercados

O artigo versa sobre o debate travado entre Say e Sismondi a respeito da possibilidade de saturação geral dos mercados. Na primeira seção, descreve-se o contexto histórico da Europa continental nas primeiras décadas do século 19, destacando-se as particularidades da experiência francesa de industrialização ante a liderança britânica nesse campo. A seguir, traça-se breve perfil da formação intelectual de Say a fim de apresentar sua visão sobre o funcionamento dos mercados. Na continuação, examina-se a perspectiva histórica de Sismondi em sua crítica da ortodoxia clássica, bem como sua versão para a tendência do sistema capitalista à superprodução. Nas duas últimas partes, recuperam-se os comentários recíprocos de Say e Sismondi a respeito de suas divergências teóricas sobre os limites da acumulação de capital.

Ética calvinista, idealismo e revolução : Carlyle e a crítica da economia vitoriana

O artigo versa sobre a doutrina econômica e social de Thomas Carlyle, célebre autor escocês do século dezenove. Inicialmente, são revistos alguns aspectos essenciais da sociedade e do capitalismo industrial na Inglaterra durante o período. Resgatam-se, a seguir, as influências religiosas e filosóficas do pensamento social de Carlyle. Após, discutem-se sua concepção da história e a versão da Revolução Francesa por ele formulada para, na seqüência, introduzir sua crítica da economia vitoriana. Ao final, avaliam-se os avanços e contradições de sua teoria social.

Uma anotação à clínica : Gilles Deleuze, esquizofrenia e sua positividade

O artigo trata a questão da esquizofrenia, tomada como um signo negativo quando se instala como patologia no campo das psicoses. Afirma que o discurso médico psiquiátrico celebrou seu advento e comemorou tais possibilidades que o pensamento "freudo-bleuleriano" abriu e desvelou. Considera que a carreira da esquizofrenia, atravessando o movimento político da antipsiquiatria, confrontou-se com outra sorte de experiências, sendo registrada segundo uma nova lógica que, sob as condições impostas pelo acontecimento freudiano, transformou o saber no século XX. Afirma que Gilles Deleuze compreendeu esse aturdimento, recolheu a parte que lhe cabia e documentou-a, em particular em sua obra Lógica do Sentido quando inverteu a polaridade dos signos, positivando a esquizofrenia.

O bebê surdo na educação infantil : um olhar sobre inclusão e práticas pedagógicas

Este estudo teve como objetivo analisar como ocorre a inclusão de dois bebês surdos (de 1 ano) na educação infantil de um Centro Municipal de Educação Infantil (CMEI) do município de Vitória/ES. Como aporte teórico foi utilizada a perspectiva Histórico-Cultural do desenvolvimento humano, sob a perspectiva que o sujeito se constitui nas relações sociais, como um ser ativo que transforma e é transformado nessas relações. Nesse contexto, o desenvolvimento implica a relação com o outro e a mediação da linguagem, meio de comunicação e de constituição do pensamento. Assim, no caso dos bebês surdos, destaca-se a LIBRAS como língua privilegiada que deve ser apropriada por eles e ensinada no cotidiano da educação infantil. Como opção metodológica, desenvolvemos um estudo de caso de inspiração etnográfica, por entendermos que essa metodologia permite atender apropriadamente ao objetivo do estudo. Para a coleta de dados, adotamos recursos como observação participante, registro em diário de campo, entrevistas semiestruturadas com os sujeitos participantes da pesquisa e análise documental. Na análise dos dados, tomamos como eixos de análise: as concepções dos profissionais a respeito da inclusão, surdez e do trabalho com os bebês surdos; o cuidado e a educação dos bebês surdos e as atividades lúdicas na sala dos bebês. As análises indicam que muitos profissionais têm dúvidas a respeito da inclusão e que a falta do conhecimento da LIBRAS por parte de muitos profissionais, leva à utilização de outros recursos de comunicação, como os gestos. A vivência e interação em LIBRAS entre as crianças e a maior parte dos profissionais da escola com os bebês surdos torna-se um desafio, sobressaindo a necessidade de mais profissionais com o conhecimento da LIBRAS para atender às crianças surdas em diferentes espaços no cotidiano da educação infantil, na perspectiva de potencializar o seu desenvolvimento e a constituição de sua identidade. Todavia, os profissionais da escola são movidos pela preocupação com a inclusão e o aprendizado da LIBRAS, esforçando-se no sentido de buscar novas formas de trabalho para/com as crianças surdas. Além disso, o empenho da equipe bilíngue na estruturação do cotidiano da educação infantil merece destaque, não só pelo trabalho que faz enquanto equipe bilíngue, mas pelo incentivo e auxílio aos outros profissionais.

A Educação Ambiental nos encontros do Congo com os cotidianos escolares de uma Escola Municipal da Barra do Jucu, Vila Velha, ES

A pesquisa “A Educação Ambiental nos encontros do Congo com os cotidianos escolares de uma Escola Municipal da Barra do Jucu, Vila Velha, ES” se apoia na produção narrativa em Educação Ambiental com os cotidianos, com a intenção de problematizar os saberes e fazeres socioambientais produzidos nos encontros entre a produção cultural do congo com as práticas escolares cotidianas. Com as conversas e narrativas dos sujeitos da pesquisa, alunos(as), professores(as), congueiros(as), pais de alunos e outros representantes da comunidade escolar, problematizamos e mapeamos esses saberesfazeres socioambientais, bem como compreendemos suas diferentes traduções. Os cotidianos escolares são considerados espaços de burla às hierarquizações culturais, ambientais, sociais e curriculares, por serem espaços privilegiados de práticas curriculares que vão além das propostas instituídas, e enfatizamos como o entorno da escola com suas especificidades locais se constituem potências para a produção de saberes e a criação de currículos cotidianamente. As oficinas de congo que acontecem na Escola Municipal da Barra do Jucu foram acompanhadas e mostraram-se potentes para o desenvolvimento da Educação Ambiental numa perspectiva pós-colonial, que acredita na possibilidade de um pensamento que vá além da relação dicotômica cultura/natureza e da não homogeneização cultural. As produções culturais desenvolvidas nas oficinas possibilitaram “outras” alternativas para a produção de subjetividades e para trocas de saberes socioambientais e culturais, baseados na solidariedade que potencializa práticas sociais sustentáveis.