Alejandro Posadas (Buenos Aires 1870 - París 1902). introductor de recursos didácticos en los procesos de enseñanza y de aprendizaje en los estudios médico-quirúrgicos en la Universidad de Buenos Aires / Alejandro Posadas (Buenos Aires 1870 - Paris 1902). introducer of teaching resources in teaching and learning processes in medicalsurgical studies at the University of Buenos Aires

Alejandro Posadas fue un destacado cirujano en la Buenos Aires del siglo XIX. Sus trabajos contribuyeron al desarrollo del conocimiento médico. El objetivo del presente artículo es describir las actividades de Alejandro Posadas desde perspectivas diferentes: cirugía, investigación, educación médica y la innovación que sus métodos aportaron al proceso de enseñanza-aprendizaje.

Alejandro Posadas was a renowned surgeon in the Buenos Aires of the XIX century. His works contributed to the development of medical knowledge. The purpose of present research article is to describe the activities of Alejandro Posadas from different perspectives: surgery research, medical education and that the innovation of his methods brought them in the teaching and learning processes.

Avaliação da atividade anti-helmíntica de extratos brutos de plantas da Floresta Amazônica e Mata Atlântica brasileira sobre Haemonchus contortus / Evaluation of the anti-helminthic activity of crude extracts from the Brazilian Amazon and Mata Atlântica plants against Haemonchus contortus

No mundo todo, as verminoses são causa de considerável prejuízo econômico na criação de ovinos. As perdas estão relacionadas ao retardo na produção, custos com tratamentos profiláticos e, em casos extremos, à morte dos animais. O objetivo deste trabalho foi verificar a ação anti-helmíntica de extratos vegetais sobre nematoides como alternativa terapêutica no tratamento da verminose em ovinos. Extratos orgânicos e aquosos foram obtidos de plantas nativas da Floresta Amazônica e Mata Atlântica, e foram testados na concentração de 100µg/mL em ensaios de toxicidade in vitro contra ovos de Haemonchus contortus e de 200µg/mL contra suas larvas. Na concentração estabelecida, apresentaram significante atividade relacionada à inibição de eclosão de ovos; em particular, o extrato orgânico de folhas e frutos de Trichilia sp. e o extrato aquoso dos órgãos aéreos de Phyllanthus attenuatus. Os resultados in vitro sugerem que extratos aquosos e orgânicos dessas plantas podem oferecer novas alternativas de controle da verminose em ovinos a partir de produtos naturais...

Helminthosis play a crucial role in small ruminant production leading to enormous economic losses particularly in areas where extensive grazing is practiced. It causes a loss of production through mortality, weight loss, reduced milk and wool production. Haemonchus contortus is a highly pathogenic small ruminant helminthes parasite, which is capable of causing acute diseases and high mortality. Therefore, there is an urgent need to seek alternative or complementary solutions to the control of parasitic nematodes of ruminants. The tropical forests concentrate the highest biodiversity in the world, particularly those located in Brazil, whose species richness is estimated to account for 20% of the total world richness and little is known about the chemical and pharmacological potentialities of Brazilian tropical forests. In this work, organic and aqueous extracts were tested on eggs and in the larval development test on Haemonchus contortus. The organic extract obtained from leaves and fruits of Trichilia sp. and the aqueous extract obtained from the aerial organs of Phyllanthus attenuates showed significant activity related to the inhibition of H. contortus egg eclosion. In vitro results suggest that both extracts, as well as eleven other active extracts, can offer alternatives in sheep worm control...

Centripetal fat patterning in South African children

The waist-to-stature ratio [WSR] is newly developed index, proposed to be of greater value as a simple anthropometric indicator, for predicting abdominal obesity and related cardiovascular co-morbidities in adults and children. This study examined age and gender differences in waist-to-stature [WSR] as measure of centripetal fat patterning in a sample of children in Pretoria, South Africa. A cross-sectional study of 1136 schoolchildren [548 boys and 588 girls] aged 9-13 [11.2 +/- 1.3] years were studied. Anthropometric measurements included body mass, stature and waist circumference. WSR was calculated by dividing waist circumference [in cm] by stature [in cm]. Data were analysed using means and standard deviation. The parametric t-test was applied to examine sexual dimorphism in fat patterning among the children. The proportion of children with a WSR /= 0.5 was 47 [8.6%], while girls were 108 [18.4%]. The prevalence of central obesity [WSR >/= 0.5] was found at all age and sex categories with the highest prevalence rate found at age 13 in both sexes. The fact that WSR >/= 0.5 [13.6%] was found in these children, even among the youngest, is a cause for concern since obesity-related problems are likely to be present among the children. The need to design and implement appropriate intervention strategies at school and community levels is evident

Intercambio epistolar entre Bernardo A Houssay y Froilán P Ludueña. Realidades del pasado de connotaciones actuales / Epistolar exchange between Bernardo A Houssay and Froilán P Ludueña. Realities of the past bearing present connotations

En el 2005 llegaron a nuestras manos una serie de cartas de Bernardo Houssay dirigidas a Froilán Ludueña. Posteriormente, las respuestas de éste. En ellas están plasmadas parte de las inquietudes y problemas que atravesaron los dos investigadores y un mínimo de contrapunto de ideas. Algunas de las razones esgrimidas se mantienen en la actualidad.

In 2005 we received a series of letters written by Bernardo Houssay and addressed to Froilán Ludueña, and afterwards, the latter’s answers. In those letters we find some of the concerns and problems which both researchers had to face, as well as a glimpse of their exchange of ideas. Some of these arguments are still valid nowadays.

Learning communicate science developing countries

En países en desarrollo se ha producido ciencia de buena calidad, como lo demuestra el número de trabajos publicados en revistas prestigiosas. Sin embargo, la capacidad de producir buenas revistas en tales países está en rémora por varias razones, particularmente la existencia de un sistema internacional de publicaciones dependiente del creciente valor atribuido a la clasificación del ISI-JCR, un enfoque adoptado por autores en todo el mundo, y por sistemas de financiamiento y evaluación. Los países en desarrollo se integraron a este contexto internacional y los esfuerzos por producir buenas revistas locales se limitan a iniciativas puntuales que casi nunca progresan. Una consecuencia importante de este déficit se refiere a la evaluación por pares, instrumento importante para la producción de buenas revistas y fomentar el progreso de la ciencia, que es una experiencia limitada en países en desarrollo. En ese escenario se discute, a la luz de datos recientes, una experiencia iniciada en Brasil y luego adoptada en doce países iberoamericanos. SciELO (Scientific Electronic Library Online) es un programa fundamentalmente apoyado por fondos públicos, dirigido al lanzamiento en línea de las mejores revistas de varios países, con acceso abierto, basadas en revisión por pares y con análisis bibliométrico/cientométrico a fin de indexarlas y mantenerlas en la base de datos. SciELO hace las funciones de un meta-editorial y aspira operar según el movimiento de acceso abierto, haciendo más disponible al conocimiento científico. Los datos presentados muestran evidencias auspiciosas de que un nuevo panorama está siendo establecido en el contexto de la producción de revistas científicas en Brasil.

Articles with authors affiliated to Brazilian institutions published from 1994 to 2003 with 100 or more citations: I - the weight of international collaboration and the role of the networks

Articles with 100 citations or more in the scientific literature and with at least one author with Brazilian affiliation, were identified in the Thomson-ISI (Institute for Scientific Information) Web of Science bibliometric database, covering a 10-year period, from 1994 to 2003; 248 (0.23 percent) out of a total of 109,916 articles with Brazilian affiliation were identified. This study was primarily carried out to identify thematic nuclei of excellence in research that had major impact in the international literature (Meneghini and Packer 2006). The regional and institutional affiliation distributions of these articles follow approximately that of the total of Brazilian articles in the ISI database. However, some significant deviations are observed derived from the outstanding performance of a few groups responsible for the publication of the HC-ISI (Highly cited ISI) papers. The international collaboration and the network organization of work played a fundamental role in these results. It is evident that the role played by organizations in research networks as well as the international collaborations exerted strong influence in the impact of these articles, although with distinct amplitude in the different fields.

Foram identificados os artigos com um mínimo de 100 citações na literatura científica e com ao menos uma filiação brasileira, segundo a base bibliométrica Thomsom ISI, no período de 10 anos entre 1994 e 2003. Dos 109.916 artigos com filiação brasileira neste período, 248 apresentaram 100 ou mais citações, ou seja, 0,23 por cento do total. Este levantamento foi feito primordialmente para identificar núcleos temáticos de excelência em pesquisa que tiveram maior impacto na literatura internacional (veja Meneghini and Packer 2006). As distribuições regional e institucional das afiliações desses artigos mais citados seguem aproximadamente aquela do total de artigos brasileiros na base ISI. No entanto, notam-se alguns desvios significativos derivados de grupos destacados quanto à publicação de trabalhos muito citados. Ficou patente que o papel das organizações em rede de pesquisa e as colaborações internacionais tiveram uma grande influência no impacto desses artigos, mas com distinta amplitude nas diversas áreas.

Articles with authors affiliated to Brazilian institutions published from 1994 to 2003 with 100 or more citations: II - identification of thematic nuclei of excellence in Brazilian science

Articles with 100 citations or more in the scientific literature and with at least one author with Brazilian affiliation, were identified in the Thomson-ISI (Institute for Scientific Information) Web of Science bibliometric database covering a 10-year period, from 1994 to 2003 (see Packer and Meneghini 2006); 248 (0.23 percent) out of a total of 109,916 articles with Brazilian affiliation were identified. This study was primarily carried out to identify thematic nuclei of excellence in research that had major impact in the international literature. Twelve of these nuclei in the fields of Biomedicine, Medicine, Biology, Physic, Chemistry and Astronomy were considered outstanding and their genesis and development were described. The weight of factors such as international collaboration and network organization are distinct in these areas and the reasons for that are discussed.

Foram identificados os artigos com um mínimo de 100 citações na literatura científica e com ao menos uma filiação brasileira, segundo Thomson-ISI (Institute for Scientific Information) Web of Science bibliometric database, no período de 10 anos entre 1994 e 2003 (veja Packer and Meneghini 2006). Este levantamento foi feito primordialmente para identificar núcleos temáticos de excelência em pesquisa que tiveram maior impacto na literatura internacional. Doze núcleos, nas áreas biomédica, médica, biológica, física, química e astronomia foram considerados proeminentes e suas gêneses e desenvolvimento foram descritos. Os pesos de fatores como colaboração internacional e organização de trabalho em rede são distintos em cada uma dessas áreas. São discutidas as razões para isso.

Absence of linkage between MHC and a gene involved in susceptibility to human schistosomiasis

Six hundred million people are at risk of infection by Schistosoma mansoni, MHC haplotypes have been reported to segregate with susceptibility to schistosomiasis in murine models. In humans, a major gene related to susceptibility/resistance to infection by S. mansoni (SM1) and displaying the mean fecal egg count as phenotype was detected by segregation analysis. This gene displayed a codominant mode of inheritance with an estimated frequency of 0.20-0.25 for the deleterious allele and accounted for more than 50 percent of the variance of infection levels. To determine if the SM1 gene segregates with the human MHC chromosomal region, we performed a linkage study by the lod score method. We typed for HLA-A, B, C, DR and DQ antigens in 11 informative families from an endemic area for schistosomiasis in Bahia, Brazil, by the microlymphocytotoxicity technique. HLA-DR typing by the polymerase chain reaction with sequence-specific primers (PCR-SSP) and HLA-DQ were confirmed by PCR-sequence-specific oligonucleotide probes (PCR-SSOP). The lod scores for the different theta values obtained clearly indicate that there is no physical linkage between HLA and SM1 genes. Thus, susceptibility or resistance to schistosomiasis, as defined by mean fecal egg count, is not primarily dependent on the host's HLA profile. However, if the HLA molecule plays an important role in specific immune responses to S. mansoni, this may involve the development of the different clinical aspects of the disease such as granuloma formation and development of hepatosplenomegaly.

Cytokine production profile of heart-infiltrating T cells in Chagas' disease cardiomyopathy

The hallmark of chronic Chagas'disease cardiomyopathy (CCC) is the finding of a T cell-rich inflammatory mononuclear cell infiltrate in the presence of extremely few parasites in the heart lesions. The scarcity of parasites in affected heart tissue casts doubt on the direct participation of Trypanosoma cruzi in CCC heart tissue lesions, and suggests the possible involvement of autoimmunity. The cells in the infiltrate are presumably the ultimate effectors of tissue damage, and there is evidence that such cells recognize cardiac myosin in molecular mimicry with T. cruzi proteins rather than primary reactivity to T. cruzi antigens (Cunha-Neto et al. (1996) Journal of Clinical Investigation, 98:1709-1712). recently, we have studied heart-infiltrating T cells at the functional levels. In this short review we summarize the studies about the role of cytokines in human and experimental T. cruzi infection, along with our data on heart-infiltrating T cells in human Chagas'cardiomyopathy. The bulk of evidence points to a significant production of IFN-gamma and TNF-alpha which may be linked to T. cruzi induced IL-12 production.

Molecular mimicry between cardiac myosin and Trypanosoma cruzi antigen B13: identification of a B13-driven human T cell clone that recognizes cardiac myosin

Previous reports from our group have demonstrated the association of molecular mimicry between cardiac myosin and the immunodominant Trypanosoma cruzi protein B13 with chronic Chagas´disease cardiomyopathy at both the antibody and heart-infiltrating T cell level. At the peripheral blood level, we observed no difference in primary proliferative responses to T. cruzi B13 protein between chronic Chagas´cardiopathy patients, asymptomatic chagasics and normal individuals. In the present study, we investigated whether T cells sensitized by T. cruzi B13 protein respond to cardiac myosin. T cell clones generated from a B13-stimulated T cell line obtained from peripheral blood of a B13-responsive normal donor were tested for proliferation against B13 protein and human cardiac myosin. The results showed that one clone responded to B13 protein alone and the clone FA46, displaying the highest stimulation index to B13 protein (SI=25.7), also recognized cardiac myosin. These data show that B13 and cardiac myosin share epitopes at the T cell level and that sensitization of a T cell with B13 protein results in response to cardiac myosin. It can be hypothesized that this also occurs in vivo during T. cruzi infection which results in heart tissue damage in chronic Chagas´disease cardiomyopathy.

Organismos tipo campylobacter en el esofago de Barrett / Organisms type campylobacter in Barrett esofhagus

Esta claro que el CP está presente en mayor o menor grado en diversa patología gastroduodenal, fundamentalmente en gastritis crónica superficial activa, úlcera gástrica y úlcera duodenal con metaplasia gástrica. Tambien se lo encuentra en gastritis crónica atrófica y en menor porcentaje si ésta tiene metaplasia intestinal, así como en algunos estómagos normales. No se lo halla en duodeno histológicamente normal ni en esófago. Como nos llamó la atención que no se hubiera realizado ninguna publicación en EB, nos dispusimos a realizar retrospectivamente, la búsqueda del CP en la metaplasia columnar del esófago distal. Su incidencia resultó elevada, 88.88% aún en aquellos casos con metaplasia intestinal, y con úlcera de Barret. Utilizamos coloración de Gram y Warthin-Starry con Alcian-Blue, y clasificándolos dentro de los Grados establecidos por Marshall y Warren. Elaboramos asimismo la discusión sobre algunos hechos fisiopatológicos, como la presencia de infiltrado PMN en todos los casos, y su importancia en el mantenimiento de la metaplasia, de las úlceras de Barrett y su posible papel en el desarrolo del adenocarcinoma

Diagnóstico y etiología del esófago de Barrett: presencia de células secretoras de gastrina (G) / Diagnosis and etiology of Barrett esophagus: presence of gastrin secreting cells (6 cells)

Presentamos las pautas diagnósticas, revisando los datos clínicos, radiológicos, endoscópicos e histológicos de 35 pacientes con Esófago de Barrett (EB) (metaplasia columnar en esófago distal). Las características clínicas son las de una esofagitis severa de larga evolución, aunque la metaplasia por sí misma, es asintomática y su clínica depende del grado de inflamación. La radiología nos revela algunos datos como reflujo GE, hernia hiatal, úlceras o estenosis, y tal vez el doble contraste haga sospechar el endobraquiesófago (EBE). La endoscopía nos proporciona datos precisos sobre la altura del EBE, úlceras, estenosis e inflamacion. La histología nos aclara el tipo de metaplasia columnar (cardial o transicional, gástrica fúndica, intestinal o especializada, ó mixta). La etiología congénita o adquirida, sujeta a controversia, puede ser aclarada con un método inmuno histoquímico, le de la Peroxidasa anti-Peroxidasa (PAP) revelándonos la presencia de células secretoras de Gastrina (G) en los casos congénitos

Measurement of intrahepatic pressure in alcoholic liver disease.

La presion intrahepatica fue medida en 172 sujetos (148 de los cuales tenian enfermedad hepatica por alcoholismo cronico; los restantes, sujetos con normal funcion y estructura hepatica, actuaron como controles). Los criterios patologicos usados para clasificar la enfermedad hepatica causada por alcoholismo fueron: lesiones minima, esteatosis, hepatitis sin fibrosis, hepatitis con fibrosis y cirrosis. Los incrementos en los valores de la presion intrahepatica estan directamente relacionados con el grado de dano estructural del higado. Cuando se efectuan conjuntamente la manometria intrahepatica y la biopsia hepatica, constituyen utiles parametros en el diagnostico del estado histologico y hemodinamico del higado en la hepatopatia por alcoholismo cronico