Study of the surface water circulation in San Blas channel (Argentina) using landsat imagery

This paper deals with the application of satellite images to study turbidity and water circulation patterns in San Blas channel during a theoretical tidal cycle. Eight Landsat TM and ETM images acquired under clear-sky conditions and representing different tidal stages were selected from a pool of Landsat images provided by the argentinean National Commission of Space Activities (CONAE) and the US Geological Survey. Standard digital image processing techniques were used to perform geometric and radiometric corrections on the visible and near-infrared bands. An image-based atmospheric correction (COST method by CHAVEZ, 1996) was applied. An ISODATA unsupervised classification was performed in order to identify different turbidity levels throughout the channel and adjacent areas. The results suggest that suspended sediment transport towards the channel mouth by ebb currents occurs along both flanks. These currents carry suspended sediment into the open sea, generating an ebb tidal delta which tends to rotate in a clockwise direction. Flood currents trigger turbidity mostly over the southern flank of the channel, generating a flood tidal delta with elongated banks extending in the direction of the tidal currents. From the elongated shape of the turbidity plumes, general tidal circulation patterns were identified.Este trabalho analisa a turbidez e a circulação da agua no canal San Blas durante um ciclo de maré teórico através de imagens satelitais. Foram utilizadas 8 imagens Landsat TM e ETM adquiridas em condições de céu claro e ao longo de diferentes momentos da maré. As imagens foram proporcionadas pela Comisión Nacional de Actividades Espaciales (CONAE) y pelo Serviço Geológico dos Estados Unidos (USGS). As correções geométricas e radiométricas foram realizadas nas bandas do espectro visível e do infravermelho próximo, utilizando técnicas padrões de processamento digital. Foi aplicada a correção atmosférica COST (CHAVEZ, 1996). Foi realizada uma classificação ISODATA não supervisionada para identificar diferentes níveis de turbidez al longo do canal e zonas adjacentes. Os resultados sugerem que o transporte de sedimento em suspensão para a boca do canal se da ao longo de ambos flancos, pela ação das correntes de refluxo. Estas correntes geram um delta de refluxo com uma tendência de rotação para a direção sul. As correntes de fluxo provocam turbidez principalmente sobre a costa sul do canal, gerando um delta de fluxo com bancos alargados na direção das correntes de maré. As plumas de turbidez permitiram identificar padrões gerais de circulação da maré

The European contribution to "Sugarbaker's protocol" for the treatment of colorectal peritoneal carcinomatosis Aportación europea al "protocolo de Sugarbaker" en el tratamiento de la carcinomatosis peritoneal colorrectal

Introduction: in 1981, Dr. PH Sugarbaker, challenging oncological orthodoxy, considered carcinomatosis to be a locoregional stage of the disease that was still susceptible to treatment with curative intent. To this end he developed a new therapeutic alternative based on the combined treatment. The macroscopic disease treated by maximum radical oncological cytoreductive surgery (through the peritonectomies described by him), followed by treatment of the residual microscopic disease with the direct intra-abdominal application of intraoperative chemotherapy with locoregional intensification, modulated by hyperthermia and early normothermic postoperative intra-abdominal chemotherapy. Using this new therapeutic regimen, known as "Sugarbaker's Protocol", his group has reported 45% survival rates in carcinomatosis of colorectal origin at 5 years, and, in selected groups of patients, 50% survival rates at 5 years. The scientific community, however, has criticized these results considering that: it is a personal experience, with a not homogenous treatment protocol with developmental modifications over time, that it is a retrospective non-randomized study, and finally that the cytostatics used in his protocol are obsolete. Various European groups have replied to these main criticisms confirming the good results that this new therapeutic alternative offers for patients with carcinomatosis of colorectal origin. The purpose of this article is to present these contributions. Material and methods: all the articles published in the English language by European groups in the world's medical literature have been reviewed using the Pubmed-MEDLINE database to identify the relevant articles related to the treatment of carcinomatosis of colorectal origin using cytoreduction and intraperitoneal chemotherapy from January 1980 to January 2008. Results: the European contribution during these 25 years in favour of the "Sugarbaker's Protocol" has consisted fundamentally in: a) one multicenter retrospective study; b) two randomized prospective phase III studies; and c) the use of oxaliplatin and irinotecan as new cytostatic agents in the protocols for intraperitoneal chemotherapy. At the same time, two new transcendental European contributions have been made in which the possibility has been considered of combined simultaneous treatment for patients with hepatic metastases and carcinomatosis, and the introduction, as a selection factor, of patients responsive to intravenous induction chemotherapy within the regimen of sandwich treatment (with systemic neoadjuvant and adjuvant chemotherapy) complementary to intraperitoneal chemotherapy. Conclusions: the results obtained by European groups using "Sugarbaker's protocol" and "Elias' protocol" with oxaliplatin compel us to request that these treatments be considered by all professionals involved in the treatment of patients with colorectal carcinomatosis as the best treatment currently available for this condition. Furthermore a randomized, prospective, multicenter study should be carried out to clarify its value and the degree of scientific evidence. A validation of this treatment will change, in the future, the dogmatic consideration of carcinomatosis as an incurable disease stage.Introducción: el Dr. P. H. Sugarbaker en 1981, desafiando la ortodoxia oncológica, consideró la carcinomatosis como un estadio locorregional de la enfermedad susceptible todavía de tratamiento con intención curativa. Para ello desarrolló una nueva alternativa terapéutica basada en el tratamiento combinado. La enfermedad macroscópica mediante la máxima cirugía citorreductora radical oncológica (merced a las peritonectomías por él descritas), seguido del tratamiento de la enfermedad microscópica residual con la aplicación directa intraabdominal, de quimioterapia de intensificación locorregional, intraoperatoria modulada por hipertermia y de quimioterapia intraabdominal normotérmica postoperatoria precoz. Con este nuevo esquema terapéutico, conocido como "Protocolo de Sugarbaker", su grupo ha publicado supervivencias en carcinomatosis de origen colorrectal de 45% a 5 años y en grupos selectos de pacientes supervivencia de 50% a 5 años. La comunidad científica, sin embargo, ha criticado estos resultados al considerar que: se trata de una experiencia personal, con un protocolo de tratamiento no homogéneo con modificaciones evolutivas en el tiempo, tratarse de un estudio retrospectivo no randomizado, y finalmente considerar que los citostáticos empleados en su protocolo son obsoletos. Diversos grupos europeos han dado respuesta a las principales objeciones, confirmando los buenos resultados que esta nueva alternativa terapéutica ofrece en pacientes con carcinomatosis de origen colorrectal. El objetivo de este trabajo es presentar estas aportaciones. Material y métodos: se han revisado todos los artículos publicados en lengua inglesa por grupos europeos en la literatura médica mundial usando la base de datos Pubmed-MEDLINE para identificar los artículos relevantes relacionados con el tratamiento de la carcinomatosis de origen colorrectal mediante citorreducción y quimioterapia intraperitoneal desde enero de 1980 a enero de 2008. Resultados: durante estos 25 años, la aportación europea como respuesta a las objeciones al "Protocolo de Sugarbaker" ha consistido fundamentalmente en: a) un estudio multicéntrico retrospectivo; b) dos estudios randomizados prospectivos fase III; y c) en la utilización del oxaliplatino e irinotecán como nuevos agentes citostáticos en los protocolos de quimioterapia intraperitoneal. Paralelamente se han producido dos nuevas aportaciones euro-peas trascendentales al considerar la posibilidad del tratamiento conjunto simultáneo en pacientes con metástasis hepáticas y carcinomatosis, y al introducir como factor de selección a los pacientes respondedores a quimioterapia intravenosa de inducción, dentro del esquema del tratamiento sándwich (con quimioterapia sistémica neoadyuvante y adyuvante) complementaria a la quimioterapia intraperitoneal. Conclusiones: la resultados obtenidos por los grupos euro-peos utilizando el "protocolo de Sugarbaker" y el "protocolo de Elias" con oxaliplatino, nos obligan a solicitar que estos tratamientos sean considerados por todos los profesionales, involucrados en el tratamiento de pacientes con carcinomatosis colorrectal, como el mejor tratamiento disponible en la actualidad para esta patología, y permita la realización de un estudio randomizado prospectivo multicéntrico que esclarezca su valía y grado de evidencia científica. La validación de este tratamiento, permitirá en el futuro cambiar el dogma de considerar a la carcinomatosis como un estadio incurable de la enfermedad