Kinetic studies of complex biomedical process by magnetic resonance: Cuban experiences.

The potentials of the magnetic resonance (MR) methods in the research of biomedical systems have been demonstrated during the 70 years of its existence. It is presented that the Cuban experience in quantitative magnetic resonance associated with molecular, preclinical and clinical studies of significant diseases and drugs development. MR "in vitro" and "in vivo" studies of sickle cell disease, the diabetic foot ulcer, the brain tumor response and the magnetic nano-particle pharmacokinetics, are presented as example. Furthermore, contributions and restrictions of magnetic resonance to diagnostic and optimization of therapeutic pathways are discussed in some concrete cases.

Impact of Increased Sonication-Induced Dispersion of Sepiolite on Its Interaction with Biological Macromolecules and Toxicity/Proliferation in Human Cells.

Sepiolite is a natural clay silicate that is widely used, including biomedical applications; notably sepiolite shows promising features for the transfer of biological macromolecules into mammalian cells. However, before its use, such an approach should address the efficiency of binding to biological macromolecules and cell toxicity. Because sepiolite spontaneously forms aggregates, its disaggregation can represent an important challenge for improving the suspension performance and the assembly with biological species. However, this can also influence the toxicity of sepiolite in mammalian cells. Here, a very pure commercial sepiolite (Pangel S9), which is present as a partially defibrillated clay mineral, is used to study the consequences of additional deagglomeration/dispersion through sonication. We analyzed the impact of extra sonication on the dispersion of sepiolite aggregates. Factors such as sonication time, sonicator power, and temperature are taken into account. With increasing sonication time, a decrease in aggregation is observed, as well as a decrease in the length of the nanofibers monitored by atomic force microscopy. Changes in the temperature and pH of the solution are also observed during the sonication process. Moreover, although the adsorption capacity of bovine serum albumin (BSA) protein on sepiolite is increased with sonication time, the DNA adsorption efficiency remains unaffected. Finally, sonication of sepiolite decreases the hemolytic activity in blood cells and the toxicity in two different human cell lines. These data show that extra sonication of deagglomerated sepiolite can further favor its interaction with some biomacromolecules (e.g., BSA), and, in parallel, decrease sepiolite toxicity in mammalian cells. Therefore, sonication represents an alluring procedure for future biomedical applications of sepiolite, even when using commercial defibrillated particles.

Modelo predictivo de crisis vasoclusiva en la anemia drepanocítica / Predictive model of vasooclusive crisis in the sickle cell deseas

Introducción: El diagnóstico precoz de la crisis vasoclusiva (CVO) que afecta a pacientes con drepanocitosis resulta un tema no resuelto en la actualidad. No se ha encontrado en la literatura evidencia de modelos que puedan establecer tempranamente índices de riesgo de la CVO para la toma de una conducta terapéutica oportuna en estos pacientes. Objetivo: Establecer índices de riesgo en pacientes con drepanocitosis, a partir de la formulación de un modelo predictivo del estado vasoclusivo. Métodos: A partir de un estudio analí tico transversal de casos y controles, realizado en el Centro Hematológico de Santiago de Cuba, se formuló a través de un análisis discriminante, un modelo predictivo del estado de CVO. Se usaron estadígrafos de dispersión (media y desviación estándar) para el establecimiento de índices de riesgo sustentados en él. Resultados: Se formuló un modelo predictivo del estado de CVO que incluyó biomarcadores del estado redox como predictores significativos en el paciente con drepanocitosis. El modelo sustentó los índices de riesgo, estratificados en 3 categorías (riesgo menor, moderado y mayor) que fueron asignados a los pacientes y posibilitó su adecuada clasificación. Conclusiones: El diseño de un modelo predictivo de CVO y el establecimiento de índices de riesgo en pacientes con drepanocitosis permitió una mejor evaluación. La nueva herramienta diagnóstica que se propone resultaría de gran utilidad en los servicios de Hematología, al facilitar una mejor valoración del estado del paciente con drepanocitosis y un tratamiento profiláctico oportuno que minimice las complicaciones asociadas a este estado.

Introduction: The early diagnosis of vasooclusive crisis affecting sickle cell patients is currently an unresolved issue. In the reviewed literature no models have been found able to establish early risk indices of vasooclusive crisis for taking a timely therapeutic behavior in these patients. Objective: To establish risk indices in sickle cell patients based on the formulation of a predictive model of vasoocclusive state. Methods: Based on a cross-sectional case-control analytic study conducted at the Hematological Center of Santiago de Cuba, a predictive model of VOC status was formulated through a discriminant analysis. Dispersion statistics (mean and standard deviation) were used to establish risk indices based on it. Results: A predictive model of the state of VOC that included biomarkers of the redox state as significant predictors of it in sickle cell patients was formulated. The model supported the risk indices, stratified into 3 categories (lower, moderate and higher risk) that were assigned to the patients and allowed an adequate classification of them. Conclusions: The design of a predictive model of VOC and the establishment of risk indices in sickle cell patients allowed a better evaluation of them. The new diagnostic tool proposed in the study would be very useful in the Hematology services, by facilitating a better assessment of the sickle cell patient's condition and a timely prophylactic treatment that minimizes the complications associated with this state.