Computational methods for analysis of dynamic events in cell migration.

Cell migration is a complex biological process that involves changes in shape and organization at the sub-cellular, cellular, and supra-cellular levels. Individual and collective cell migration can be assessed in vitro and in vivo starting from the flagellar driven movement of single sperm cells or bacteria, bacterial gliding and swarming, and amoeboid movement to the orchestrated movement of collective cell migration. One key technology to access migration phenomena is the combination of optical microscopy with image processing algorithms. This approach resolves simple motion estimation (e.g. preferred direction of migrating cells or path characteristics), but can also reveal more complex descriptors (e.g. protrusions or cellular deformations). In order to ensure an accurate quantification, the phenomena under study, their complexity, and the required level of description need to be addressed by an adequate experimental setup and processing pipeline. Here, we review typical workflows for processing starting with image acquisition, restoration (noise and artifact removal, signal enhancement), registration, analysis (object detection, segmentation and characterization) and interpretation (high level understanding). Image processing approaches for quantitative description of cell migration in 2- and 3-dimensional image series, including registration, segmentation, shape and topology description, tracking and motion fields are presented. We discuss advantages, limitations and suitability for different approaches and levels of description.

[Fast pathway for heart surgery]. / Vía rápida para cirugía cardiaca.

The increasing demographic and life expectancy rates, together with the vertiginous technological development during the last two decades, have raised the number of cardiac patients requiring surgical treatment. Therefore, several institutions have been forced to give priority to advanced or more serious cases and to postpone those that do not demand an urgent surgery. This analysis was made from June 15, 1999 to June 15, 2000 and demonstrates the results obtained from maintaining a fast track at the National Institute of Cardiology "Ignacio Chávez". This has favored the practice of surgeries in cases with noncomplex pathologies, null mortality, and low morbidity rates. The analysis also compares results from patients who had been subjected to surgery for the same type of pathologies but following the usual course of admittance and surgery scheduling, proving to be cost-efficient. It also demonstrates the high incidence of inter-auricular communication and the Von Willebrand disease that exist in our environment. Based on the results, we propose to maintain and increase this type of surgeries, addressing their limitations.

The compound 14-keto-stypodiol diacetate from the algae Stypopodium flabelliforme inhibits microtubules and cell proliferation in DU-145 human prostatic cells.

We investigated the effects of the drug 14-keto-stypodiol diacetate (SDA) extracted from the seaweed product Stypopodium flabelliforme, in inhibiting the cell growth and tumor invasive behavior of DU-145 human prostate cells. In addition, the molecular action of the drug on microtubule assembly was analyzed. The effects of this diterpenoid drug in cell proliferation of DU-145 tumor cells in culture revealed that SDA at concentrations of 5 microM decreased cell growth by 14%, while at 45 microM a 61% decrease was found, as compared with control cells incubated with the solvent but in the absence of the drug. To study their effects on the cell cycle, DU-145 cells were incubated with increasing concentrations of SDA and the distribution of cell-cycle stages was analyzed by flow cytometry. Interestingly, the data showed that 14-keto-stypodiol diacetate dramatically increased the proportion of cells in the G2/M phases, and decreased the number of cells at the S phase of mitosis, as compared with appropriate controls. Studies on their action on the in vitro assembly of microtubules using purified brain tubulin, showed that SDA delayed the lag period associated to nucleation events during assembly, and decreased significantly the extent of polymerization. The studies suggest that this novel derivative from a marine natural product induces mitotic arrest of tumor cells, an effect that could be associated to alterations in the normal microtubule assembly process. On the other hand, a salient feature of this compound is that it affected protease secretion and the in vitro invasive capacity, both properties of cells from metastases. The secretion of plasminogen activator (u-PA) and the capacity of DU-145 cells to migrate through a Matrigel-coated membrane were significantly inhibited in the presence of micromolar concentrations of SDA. These results provide new keys to analyze the functional relationships between protease secretion, invasive behavior of tumor cells and the microtubule network.

[Coronary revascularization without extracorporeal circulation. An alternative therapy (preliminary report)]. / Revascularización coronaria sin circulación extracorpórea. Una alternativa terapéutica. (Reporte preliminar).

Direct myocardial revascularization techniques has earned great acceptance in the treatment of ischemic coronary syndromes in the past two decades. Almost since its beginnings the procedure was done with the aid of extracorporeal circulation, since the technical accessibility with cardiac standstill further helped to evolve the procedure. As years went by, complications due to the use of the pump became evident, such as microembolism, bleeding disorders, and others. Besides this, there is a special group of patients, those with high surgical risk, with preexisting pulmonary, hepatic or cerebral disease, who benefit a great deal when bypass grafting procedure is done without the pump. In this article we delineate the indications, contraindications, and the procedure itself based in our personal experience, reporting our first five patients with this technique.

Relación entre el estado nutricional de la embarazada y el peso del recién nacido de Chiloé / Relatinship between nutritional status of pregnant women and the newborn infant body uveight in Chiloé

Se estudia, por primera vez en la provincia de Chiloé, el binomio embarazada-recién nacido, para relacionar las variables que tienen influencia en el peso de nacimiento. A través de un análisis retrospectivo de 220 mujeres con embarazo simple, se establece que entre las variables estudiadas, las semanas de gestación, así como también el estado nutricional inicial de la madre, muestran una influencia sobre el peso al nacer. Resultados similares se han obtenido en estudios realizados en otras provincias del país. Los nacimientos tuvieron un peso promedio global de 3 303 g para el sexo masculino y 3 167 g para el femenino, resultado que están por debajo del patrón NCHS. Con menos de 38 semanas de gestación se observaron nacimientos con predominio de un peso inferior a 3 001 g. No se establecieron diferencias significativas al relacionar las variables estado nutricional inicial e incremento promedio de peso semanal, observándose una tendencia de las madres que iniciaron sus controles con un estado nutricional normal y sobrepeso a tener nacimientos con un peso adecuado, estableciéndose que las madres que iniciaron su gestación con un estado nutricional bajo peso y que lograron incrementos promedio mayor a 400 g por semana obtuvieron hijos con un peso promedio de nacimiento mayor a 3 000 g. Finalmente se analizaron otras variables que pudieron tener influencia sobre el peso de nacimiento, para lograr establecer un perfil de la madre que condicionó productos con un peso de nacimiento por sobre los 3 000 g.