Abstract Adenosine is an important regulator within the cardiovascular system and modulates various processes through four distinct G protein-coupled receptors (A1, A2A, A2B, and A3), causing hypotension and reduced renal blood flow, which contributes to ischemia tissue and organ dysfunction. Caffeine causes most of its biological effects by blocking adenosine receptors. Although caffeine is vastly used as a pharmacological tool in basic research, there is a lack of studies characterizing the caffeine doses necessary for blocking the cardiovascular effects of adenosine. Therefore, we evaluated the effect of different doses of caffeine (10, 30 and 100 mg/kg, s.c) on the cardiovascular changes induced by adenosine. In addition, the adenosine response was evaluated at different times (4 and 8 hours) after caffeine administration. The bolus injection of increasing doses of adenosine dose-dependently reduced blood pressure, renal blood flow and heart rate. The dose of 30 mg/kg was the most effective in blocking adenosine-induced cardiovascular events. However, the higher dose of caffeine (100 mg/kg) fails to block the adenosine effect on heart rate. The effect of caffeine lasts for 4 hours. Therefore, caffeine in the dose of 30 mg/kg can block the effects of adenosine for up to 4 hours. These data provide valuable information on the dose and frequency of caffeine administration for future studies in rats.

Abstract Objective: Periodontitis is associated with endothelial dysfunction, which is clinically characterized by a reduction in endothelium-dependent relaxation. However, we have previously shown that impairment in endothelium-dependent relaxation is transient. Therefore, we evaluated which mediators are involved in endothelium-dependent relaxation recovery. Material and methods: Rats were subjected to ligature-induced experimental periodontitis. Twenty-one days after the procedure, the animals were prepared for blood pressure recording, and the responses to acetylcholine or sodium nitroprusside were obtained before and 30 minutes after injection of a nitric oxide synthase inhibitor (L-NAME), cyclooxygenase inhibitor (Indomethacin, SC-550 and NS- 398), or calcium-dependent potassium channel blockers (apamin plus TRAM- 34). The maxilla and mandible were removed for bone loss analysis. Blood and gingivae were obtained for C-reactive protein (CRP) and myeloperoxidase (MPO) measurement, respectively. Results: Experimental periodontitis induces bone loss and an increase in the gingival MPO and plasmatic CRP. Periodontitis also reduced endothelium-dependent vasodilation, a hallmark of endothelial dysfunction, 14 days after the procedure. However, the response was restored at day 21. We found that endothelium-dependent vasodilation at day 21 in ligature animals was mediated, at least in part, by the activation of endothelial calcium-activated potassium channels. Conclusions: Periodontitis induces impairment in endothelial-dependent relaxation; this impairment recovers, even in the presence of periodontitis. The recovery is mediated by the activation of endothelial calcium-activated potassium channels in ligature animals. Although important for maintenance of vascular homeostasis, this effect could mask the lack of NO, which has other beneficial properties.

<p>In this study, nifedipine (NFP)-loaded polymeric nanocapsules were prepared and characterised with a view to protect the drug from degradation. Nanocapsule suspensions were prepared using two different surfactants (pluronic F68 and polyvinyl alcohol). Physicochemical stability and <italic>in vivo</italic>antihypertensive effect were evaluated. The particle size, zeta potential and entrapment efficiency remained constant during a period of 28 days of exposure under light irradiation. A smaller particle size and a higher zeta potential were obtained for the nanocapsules prepared with Pluronic F68 as surfactant. The solid drug and the nanocapsules were submitted to light exposure for 28 days. After this period of time, the percentage of drug remaining in the PF68NFP and PVANFP nanocapsules was 28.1% and 21.3%, respectively. In contrast, the solid drug was completely degraded after 4 days, suggesting that the nanocapsule suspensions promoted significant protection of the drug against light exposure. In addition, <italic>in vivo</italic> studies were carried out, which demonstrated that the formulations with polyvinyl alcohol exhibited a very rapid onset of action after oral administration in rats and led to faster drug release. The nanoparticles developed can be considered as an alternative for improving NFP stability in liquid formulations.</p>

Os anti-inflamatórios inibidores das ciclo-oxigenases (COX) representam a classe de fármacos mais comumente utilizada. A COX corresponde a uma classe de enzimas conservadas evolutivamente e tem duas isoformas principais: a COX-1 e a COX-2. Seus subprodutos têm papel fundamental na inflamação e na percepção da dor. Há uma grande discussão entre a inibição seletiva ou não da COX pelo fato de a mesma, além de participar dos eventos inflamatórios, ter papel fundamental na manutenção da homeostase do organismo. A inibição seletiva da COX-2 surgiu com o intuito de reduzir os efeitos deletérios gastrintestinais de uma inibição não seletiva; em contrapartida, a inibição exclusiva da COX-2 associou-se a sérios eventos cardiovasculares, por causar um desequilíbrio entre a produção de prostaciclina e tromboxano. O objetivo deste trabalho é revisar a literatura a esse respeito, apontando os prós e os contras da inibição seletiva ou não das enzimas ciclo-oxigenases.

The cyclooxygenase (COX) inhibitors are the most common drugs used worldwide. COX corresponds to an evolutionarily conserved class of enzymes and has two main isoforms: COX-1, which is largely associated with physiological functions, and COX-2, which is largely associated with pathological functions. Their subproducts have an important role in inflammation and pain perception. The COX-2 selective inhibition was designed to minimize gastrointestinal complications of non-selective inhibition. However, this exclusive COX-2 inhibition was associated with serious cardiovascular events, for causing an imbalance between prostacyclin and thromboxane production. The objective of this study is to discuss the mechanisms underlying the cardiovascular effects, pointing out the advantages and disadvantages of the selective or nonselective COX inhibitors.

The success of revascularization procedures is limited by recurrent stenosis, which is a narrowing of a blood vessels that results from neo-intimal hyperplasia. The renin-angiotensin-aldosterone system has been implicated in the pathogenesis of neo-intimal hyperplasia, and a role for angiotensin II in vascular smooth muscle cell proliferation has been proposed. There are at least two high-affinity subtypes of angiotensin II receptors, AT1 and AT2, both of which are seven-transmembrane G protein-coupled receptors. We investigated the effect of losartan, an AT1 receptor antagonist, on vascular smooth muscle cell proliferation using the A7r5 smooth cell line derived from rat aorta. Losartan was shown to prevent angiotensin II-induced cell proliferation, thereby suggesting that the effect of angiotensin II was mediated via AT1 receptors. These data strengthen the concept that inhibitors of the renin-angiotensin system can effectively prevent recurrent stenosis.

O presente trabalho decorre de uma pesquisa sobre a atenção em sala de aula realizada com alunos e professores de duas turmas de primeira série do ensino fundamental. Foram realizadas aproximadamente cem observações, com notas de campo e gravações dos diálogos que se desenrolaram entre alunos e professores e a metodologia de análise do material foi qualitativa. Tais diálogos foram analisados, posteriormente, com o propósito de identificar breakdowns. Estes foram definidos como modulações da atenção expressas através de falas e gestos que apontavam para uma aparente ruptura do foco atencional, revelando um desvio do trabalho recognitivo em questão. O resultado das análises apontou para a predominância de duas modalidades distintas de atuação da professora diante do encontro com os breakdowns, sugerindo, como conclusão da pesquisa, que a atenção pode ser efeito da aprendizagem quando o ambiente, criado por aqueles que ensinam, tem o propósito de que todos possam acercar-se, o mais possível, de um sentido compartilhado de comunicação, caracterizando-a por uma autêntica relação de cooperação.

This paper derives from a research project on attention in classroom. The work was carried out with teachers and students of two classes of the first grade of fundamental school. We achieved approximately one hundred observations with notes fields and recordings of the dialogues that happened among students and teachers. The methodology of analysis we used was qualitative research. The dialogues were analyzed with the purpose of identifying the breakdowns. They were defined as modulations of attention expressed through the sPEEches and gestures that pointed to an apparent rupture of the attentive focus revealing a detour of the recognition focus. The results of analysis pointed to a predominance of two different modalities of attention of the teacher concerning the breakdowns, suggesting as conclusion that attention can affect learning when classroom environment is perceived within a sense of communication and authentic relation of co-operation.

El presente trabajo resulta de una investigación sobre la atención en salón de clase realizada con alumnos y profesores de dos grupos de primer grado de la enseñanza primaria. Fueron realizadas aproximadamente cien observaciones, con notas de campo y grabaciones de los diálogos que ocurrieron entre alumnos y profesores y la metodología de análisis del material fue cualitativa. Estos diálogos fueron analizados, posteriormente, con la finalidad de identificar breakdowns. Estos fueron definidos como modulaciones de la atención expresadas por medio de intervenciones orales y gestos que señalaban una aparente ruptura del foco de atención, revelando un desvío del trabajo recognitivo en cuestión. El resultado de los análisis mostró la predominancia de dos modalidades distintas de actuación de la profesora al encontrarse con breakdowns, sugiriendo, como conclusión de la investigación, que la atención puede ser efecto del aprendizaje cuando el ambiente, creado por aquellos que enseñan, tiene el propósito de que todos puedan acercarse, lo máximo posible, de un sentido compartido de comunicación, caracterizándola como una auténtica relación de co-operación.

O presente artigo tem como objetivos precípuos: apresentar e discutir as formas de atenção e suas relações com a aprendizagem na contemporaneidade, buscando fazer aproximações com duas formas de construção subjetivas: a pedagógica e a informacional. Pretende-se apresentar, em seguimento, os resultados de um estudo piloto realizado em uma primeira série do ensino fundamental. O objetivo da pesquisa foi estudar os modos de atenção dispensados por alunos e professores durante o processo de ensino e aprendizagem e analisar seus desdobramentos. O estudo sugeriu que a sala de aula pode ser um espaço de aprendizagem de um modo de atenção aberto à invenção, a medida que se torna possível experimentar, principalmente, o acolhimento do inesperado, que surge num momento de ruptura do foco atencional, e a instalação de uma dinâmica de atuação comunicativo-dialógica-interacional, que implica na valorização do pensamento e do princípio de co-operação.

The main goal of this paper is to discuss the ways attention has been understood and its relations with learning in the contemporary world, by trying to relate it with two ways of subjective constructions: the pedagogic and the informational. Following is the presentation of the results of a pilot study done with the first grade of a grammar school. The purpose of the research was to study the ways attention was experienced between students and teachers during the learning process and analyze its development. It suggested that the classroom could be a space of learning of an attention open to invention as long as it is possible to experience the sudden reception that emerges from a rupture of the focus. Also, it suggested the need of a dialogical dynamics of communication based on the principle of interaction and co-operation.

O presente trabalho decorre de um estudo piloto sobre a atenção em sala de aula realizado com crianças de primeira série do ensino fundamental. O objetivo foi analisar algumas das especificidades das relações ali estabelecidas que pudessem revelar-se propícias a um modo de atenção de caráter mais inventivo e problematizador. O estudo sugeriu que a construção de um espaço de comunicação dialógica favorece a capacidade atentiva dos alunos. Neste espaço, os alunos passam a experienciar a aprendizagem da atenção diversamente do modo automático como habitualmente recebem informações e são chamados a experimentar a atenção na aprendizagem. Isto se deve, principalmente, à capacidade da professora de acolher um momento de ruptura do foco atencional e manter-se num estado de abertura para o inesperado.

This paper derives from a pilot study on classroom attention undertaken with first grade children. The objective was to analyze some particularities of the relationships that were established and that may reveal propitious towards a form of attention characteristically more inventive and inquisitive. The study suggested that building an environment of dialogical communication favors the student's attentive capacity. In this environment, students are called upon to experience attention in learning which is different from the habitual manner that they are used to in receiving information. This is due, mainly, to the capacity of the teacher in giving heed to a moment of rupture from the attentive focus and keeping oneself open-minded for the unexpected.

O artigo procura situar o tema da inteligência humana na perspectiva psicanalítica, em especial, da contribuição de Silvia Bleichmar, explorando como a mente humana desenvolve a atividade intelectual a partir de seus estados embrionários. É reconhecida a contribuição da epistemologia genética desenvolvida por Jean Piaget que nos permite compreender a capacidade de construir sistemas simbólicos a partir de esquematismos sensório-motores. São também salientadas algumas convergências entre o pensamento piagetiano e o pensamento psicanalítico. O que é enfatizado neste artigo, entretanto, é que a contribuição psicanalítica sobre os primórdios da inteligência tem sido bem menos estudada, embora de grande interesse teórico e clínico. A inspiração teórica deste artigo, a partir dos estudos de Bleichmar, apoia-se fortemente em Freud, mas fundamenta-se de forma mais decisiva na orientação da escola francesa de Jean Laplanche. O artigo procura mostrar que, para alcançar a objetividade das estruturas lógicas, caracterizadas pelas categorias da lógica aristotélica - classificação, espaço, tempo, causalidade e negação - o psiquismo realiza um ativo trabalho de ligação dentro da mente que se inicia nas primeiras inscrições do outro humano sexualizado e que necessita implantar a repressão originária, única operação capaz de organizar a lógica do pensamento secundário. Enfatiza, ao final, que a contribuição sobre uma teoria das origens do psiquismo, no que concerne ao desenvolvimento da inteligência, permite ajudar nos estudos sobre os problemas de aprendizagem, diferenciando as dificuldades secundárias à construção do conhecimento dos transtornos que remetem ao não constituído do ego.

This paper aims to discuss human intelligence in the psychoanalytical perspective, particularly considering the contribution of Silvia Bleichmar who explores how human mind develops the intellectual activity from the embryonic states. It is recognized the contribution of genetic epistemology developed by Jean Piaget which allows to understand the capacity to build symbolic systems from sensory-motor schemes. There is also pointed some convergence between the genetic psychology and the psychoanalytic thought. What is stressed in this article, however, is that the contribution of psychoanalysis about the origins of intelligence has been less studied, although it is of most interest both theoretically and clinically. The theoretical inspiration of the paper relies on Freud's theory but it is more definitely grounded on the French school of Jean Laplanche. It tries to show that to reach the objectivity of logical structures, characterized by the categories of the Aristotelian logic - classification, space, time, causality, denial - the psychism does an active work of mind connection which starts in the first inscriptions of the other sexualized human and has to implant the originary repression, the only one able to organize the logic of the secondary thought. It stresses, at the end, that the contribution about a theory of the origins of psychism, concerning the development of intelligence is of great help in the studies about learning disabilities, as it differentiates learning difficulties due to secondary causes of the disorders which address to the lack of constitution of the ego.