Cardiac beta-receptors in experimental Chagas' disease

Experimental Chagas' disease (45 to 90 days post-infection) showed serious cardiac alterations in the contractility and in the pharmacological response to beta adrenergic receptors in normal and T. cruzi infected mice (post-acute phase). Chagasic infection did not change the beta receptors density (78.591 ± 3.125 fmol/mg protein and 73.647 ± 2.194 fmol/mg protein for controls) but their affinity was significantly diminished (Kd = 7.299 ± 0.426 nM and Kd = 3.759 ± 0.212 nM for the control) p < 0.001. This results demonstrate that the alterations in pharmacological response previously reported in chagasic myocardium are related to a significantly less beta cardiac receptor affinity. During this experimental period serious cardiac cell alterations take place and functional consequences will be detected in the chronic phase.

Frequency of suspected cases of neurocysticercosis detected by computed skull tomography in Santa Maria, RS, Brazil

Due to the lack of studies about neurocysticercosis in the South of Brazil, an investigation was conducted to determine the percentage of suspected cases of neurocysticercosis in computed tomography diagnoses in Santa Maria, RS, from January 1997 to December 1998. Of 6300 computed tomographies (CT) of the skull performed at the private Hospital de Caridade Astrogildo de Azevedo, 80, i.e., 1.27% were suspected of neurocysticercosis. Fifty were women (62.5%) and 30 were men (37.5%). The most frequent radiological manifestation indicating neurocysticercosis was the presence of calcifications (isolated or associated), with a 95% rate (76 cases), while the presence of hypodense lesions reached a 5% rate (4 cases). After routine analysis, each CT was evaluated again and the suspected cases were confirmed. The percentage of suspected cases of neurocysticercosis detected by CT in the present study carried out in Santa Maria was considered low (1.27%). This can be explained by the fact that tomography is not accessible to the economically underprivileged population of Santa Maria. We hope that the present study can alert the population and the professionals to the fact that neurocysticercosis is a more frequent disease than indicated by the few diagnoses made.

A change in the treatment of abdominal aortic aneurysms

OBJECTIVE: One of the most exciting potential applications of percutaneous therapy is the treatment of abdominal aneurysms. METHODS: Of 230 patients treated with a self-expanding polyester-lined stent-graft for different aortic pathologies at our institution, we selected 80 abdominal aneurysm cases undergoing treatment (from May 1997 to December 2002). The stent was introduced through the femoral artery, in the hemodynamic laboratory, with the patient under general anesthesia, with systemic heparinization, and induced hypotension. RESULTS: The procedure was successful in 70 (92.9%) cases; 10 patients with exclusion of abdominal aortic aneurysms were documented immediately within the hemodynamic room and 5 patients persisted with a residual leak. Two surgical conversions were necessary. Additional stent-grafts had to be inserted in 3 (3.7%) cases. In the follow-up, 91.4% of patients were alive at a mean follow-up of 15.8 months. CONCLUSION: We believe that stent-grafts are an important tool in improving the treatment of abdominal aneurysms, and this new policy may change the conventional medical management of these patients.

Estudio de receptores beta cardíacos en la enfermedad de Chagas experimental

Hasta el momento no hay una explicación definitiva sobre los mecanismos etiopatogénicos de la miocardiopatía chagásica. A partir de las alteraciones farmacológicas y lesiones histopatológicas descriptas en trabajos anteriores y coincidiendo con otros autores, pensamos que el compromiso de la perfusión vascular y las reacciones de autoinmunidad podrían involucrar modificaciones en los receptores beta cardíacos. Hemos realizado un seguimiento evolutivo de estos receptores desde los 35 días a los 135 días post inoculación con tripomastigotes cepa Tulahuen y comprobamos que las alteraciones histológicas y farmacológicas se correlacionan con los cambios de afinidad y densidad de dichos receptores de acuerdo a la etapa en estudio (aguda, indeterminada y crónica). Asimismo se demostró que la cantidad de Trypanosoma cruzi que ingresa al huésped determina y acelera la evolución de la miocardiopatía chagásica. Continuando con la línea de estudio de los receptores beta cardíacos en los distintos estadíos de la enfermedad chagásica experimental, nos proponemos estudiar las características dinámicas de las membranas miocárdicas determinando su composición en fosfolípidos y otros componentes polares. A la vez se plantea estudiar si el tratamiento con beta bloqueante incide en los desórdenes que se producen en los receptores beta cardíacos de animales inoculados con T. cruzi , cepa Tulahuen. Por lo antes mencionado, se intenta lograr un aporte que desde el área básica se podría dar para esclarecer la fisiopatogenia de la miocarditis chagásica y colaborar en el enfoque de nuevas acciones terapéuticas.

Tratamento endovascular da persistência do canal arterial em adulto

A persistência do canal arterial (PCA) é uma anomalia relativamente freqüente e de simples correção. A correção envolve a ligadura do ducto com ou sem a sua secção. A anomalia em adultos pode provocar hipertensão pulmonar persistente e disfunção ventricular. A correção em adultos é controversa e de maior risco. Um caso de correção endovascular com acesso intra-abdominal da PCA em adulto é descrito.

Cirurgia de revascularização do miocárdio usando apenas tomografia computadorizada como angiograma pré-operatório

A cirurgia de revascularização do miocárdio (CRM) é um procedimento bem estabelecido com indicações atuais precisas. O advento e a disseminação dessa técnica foram possíveis após a introdução do angiograma coronário. Embora muitos métodos de avaliação tenham evoluído nos últimos anos, nenhum conseguiu substituir o angiograma coronário invasivo como exame pré-operatório. A tomografia computadorizada (TC) emergiu como uma alternativa ao angiograma coronário invasivo. O presente relato descreve dois casos de CRM realizadas usando-se apenas a TC como técnica de avaliação anatômica das artérias coronárias pré-operatória.

Studies of membrane fluidity and heart contractile force in Trypanosoma cruzi infected mice

In Chagas disease serious cardiac dysfunction can appear. We specifically studied the cardiac function by evaluating: ventricle contractile force and norepinephrine response, affinity and density of beta-adrenergic receptors, dynamic properties of myocardial membranes, and electrocardiography. Albino swiss mice (n = 250) were infected with 55 trypomastigotes, Tulahuen strain and studied at 35, 75, and 180 days post-infection, that correspond to the acute, indeterminate, and chronic phase respectively. Cardiac beta-adrenergic receptors' affinity, myocardial contractility, and norepinephrine response progressively decreased from the acute to the chronic phase of the disease (p < 0.01). The density (expressed as fmol/mg.prot) of the receptors was similar to non-infected mice (71.96 ± 0.36) in both the acute (78.24 ± 1.67) and indeterminate phases (77.28 ± 0.91), but lower in the chronic disease (53.32 ± 0.71). Electrocardiographic abnormalities began in the acute phase and were found in 65% of the infected-mice during the indeterminate and chronic phases. Membrane contents of triglycerides, cholesterol, and anisotropy were similar in all groups. A quadratic correlation between the affinity to beta-adrenergic receptors and cardiac contractile force was obtained. In conclusion the changes in cardiac beta-adrenergic receptors suggests a correlation between the modified beta-adrenergic receptors affinity and the cardiac contractile force.

Using self organizing maps on compositional data

Self-organizing maps (Kohonen 1997) is a type of artificial neural network developedto explore patterns in high-dimensional multivariate data. The conventional versionof the algorithm involves the use of Euclidean metric in the process of adaptation ofthe model vectors, thus rendering in theory a whole methodology incompatible withnon-Euclidean geometries.In this contribution we explore the two main aspects of the problem:1. Whether the conventional approach using Euclidean metric can shed valid resultswith compositional data.2. If a modification of the conventional approach replacing vectorial sum and scalarmultiplication by the canonical operators in the simplex (i.e. perturbation andpowering) can converge to an adequate solution.Preliminary tests showed that both methodologies can be used on compositional data.However, the modified version of the algorithm performs poorer than the conventionalversion, in particular, when the data is pathological. Moreover, the conventional ap-proach converges faster to a solution, when data is \well-behaved".Key words: Self Organizing Map; Artificial Neural networks; Compositional data

Identification of sap-feeder instars in Angelabella tecomae Vargas & Parra (Lepidoptera, Gracillariidae) feeding on Tecoma fulva fulva (Bignoniaceae)

The number of sap-feeding instars of the leaf-miner Angelabella tecomae Vargas & Parra, 2005 was determined by measuring the head capsule exuviae collected from mines (n = 125) on the shrub Tecoma fulva fulva D. Don (Bignoniaceae) in the Azapa Valley, northern Chile. Sap-feeding larvae went through four instars in 120 occasions while five larvae went through five instars. The possible causes for this variation and the usefulness of this tool for future studies are discussed.

Egg laying site selection by a host plant specialist leaf miner moth at two intra-plant levels in the northern Chilean Atacama Desert

Egg laying site selection by a host plant specialist leaf miner moth at two intra-plant levels in the northern Chilean Atacama Desert. The spatial distribution of the immature stages of the leaf miner Angelabella tecomae Vargas & Parra, 2005 was determined at two intra-plant levels (shoot and leaflet) on the shrub Tecoma fulva fulva (Cav.) D. Don (Bignoniaceae) in the Azapa valley, northern Chilean Atacama Desert. An aggregated spatial pattern was detected for all the immature stages along the shoot, with an age dependent relative position: eggs and first instar larvae were clumped at apex; second, third and fourth instar larvae were mostly found at intermediate positions; meanwhile the spinning larva and pupa were clumped at basis. This pattern suggests that the females select new, actively growing leaflets for egg laying. At the leaflet level, the immature stages were found more frequently at underside. Furthermore, survivorship was higher for larvae from underside mines. All these results highlight the importance of an accurate selection of egg laying site in the life history of this highly specialized leaf miner. By contrast, eventual wrong choices in the egg laying site selection may be associated with diminished larval survivorship. The importance of the continuous availability of new plant tissue in this highly human modified arid environment is discussed in relation with the observed patterns.

Using self organizing maps on compositional data

Self-organizing maps (Kohonen 1997) is a type of artificial neural network developed to explore patterns in high-dimensional multivariate data. The conventional version of the algorithm involves the use of Euclidean metric in the process of adaptation of the model vectors, thus rendering in theory a whole methodology incompatible with non-Euclidean geometries. In this contribution we explore the two main aspects of the problem: 1. Whether the conventional approach using Euclidean metric can shed valid results with compositional data. 2. If a modification of the conventional approach replacing vectorial sum and scalar multiplication by the canonical operators in the simplex (i.e. perturbation and powering) can converge to an adequate solution. Preliminary tests showed that both methodologies can be used on compositional data. However, the modified version of the algorithm performs poorer than the conventional version, in particular, when the data is pathological. Moreover, the conventional ap- proach converges faster to a solution, when data is \well-behaved". Key words: Self Organizing Map; Artificial Neural networks; Compositional data

Adaptación de métodos diferentes ante necesidades educativas concretas.

Comunicación en la que se analizan las características del Colegio Público San Pedro de Alcántara (Badajoz) y en especial de su alumnado, donde el 80 por ciento de niños son gitanos, algunos padecen deficiencias psíquicas, otros presentan problemas graves de conducta, etc. Una vez planteadas estas características se detallan las necesidades del centro y los métodos de enseñanza precisos para atender a estos alumnos.

Exposiciones de pintura en Madrid.

Crónica crítica sobre las exposiciones de pintura de Vidal y Cuadras, en la Galería Palma; José Togores, en el Museo de Arte Moderno; Rafael Pellicer, en el Círculo de Bellas Artes, Francisco Mateos, en la Sala Buchcholz y Fernando Sáez, en la Sala Clan de Madrid.

A qualificação da mão-de-obra da agroindústria de frigorífico bovino do Mato Grosso do Sul frente às inovações tecnológicas : estudo de casos

O presente trabalho identificou as transformações nas qualificações dos trabalhadores ligados à produção na agroindústria de frigorífico de bovinos, com a introdução de novas tecnologias no processo produtivo. Com o auxílio de metodologia de natureza qualitativa foram realizados levantamentos em três frigoríficos de bovinos, sendo dois em Mato Grosso do Sul e outro frigorífico de referência no segmento, situado no estado de Goiás. Através de entrevistas semi-estruturadas junto a operários, supervisores, gerentes e de especialistas do setor, bem como de observações efetuadas sobre o processo produtivo, buscou-se captar as modificações ocorridas e as que deverão ocorrer no processo de produção, bem como os requisitos de qualificação da mão-de-obra para operá-lo. Foi construído o roteiro das entrevistas, tendo em vista os objetivos do trabalho, buscando captar as percepções dos diferentes interlocutores, bem como buscando identificar a complexidade das atividades e a forma de interação entre as pessoas nas diferentes fases do processo produtivo. Como resultado estabeleceu-se o perfil requerido para os trabalhadores que participarão diretamente do processo produtivo, bem como os programas de qualificação para atender as necessidades decorrentes das novas tecnologias a serem implementadas.