A Mechanism of crystallization process of hemoglobin S

 It has been studied as the qualitative consequence of a proposed mechanism of reaction for the formation of HbS molecular aggregations, as well as the mathematical model associated with it, for the particular case that the process of crystallization takes place at partial pressure and constant temperature. It is showed that the results mentioned in the study can be used to explain experimental existing data, although this data are small to decide between various options that are compatible with existing experimental models and experimental data. Also, qualitative consequences of to mechanism of reaction suggested for the formation of HbS molecular aggregations, as well as the mathematical model associated, are studied for a particular case in which to process of crystallization under constant oxygen, partial pressure and constant tem-peratures. The results of such study, which are able to explain the existing experi­mental data, are shown. However, this is latter very scarce for being able to decide among various existing choices compatible with the model and experimental data.  It has been studied as the qualitative consequence of a proposed mechanism of reaction for the formation of HbS molecular aggregations, as well as the mathematical model associated with it, for the particular case that the process of crystallization takes place at partial pressure and constant temperature. It is showed that the results mentioned in the study can be used to explain experimental existing data, although this data are small to decide between various options that are compatible with existing experimental models and experimental data. Also, qualitative consequences of to mechanism of reaction suggested for the formation of HbS molecular aggregations, as well as the mathematical model associated, are studied for a particular case in which to process of crystallization under constant oxygen, partial pressure and constant tem-peratures. The results of such study, which are able to explain the existing experi­mental data, are shown. However, this is latter very scarce for being able to decide among various existing choices compatible with the model and experimental data. &nbsp

A Model of the Molecular Aggregate Processes of Hemoglobin S. Absence of Cristallization

The molecular aggregate formation mechanisms play a major role in the interpretation of the pathophysiology of Sickle Cell disease and in the selection of the therapeutic strategies to follow.  A mechanism and a mathematical model are proposed. The model postu-lates the existence of defective microtubules formed by deoxy hemoglobin S and oxy hemoglobin S, and explains the dependence of polymerization on hemoglobin concentration, temperature, and partial oxygen pressure. The analysis focuses on the polymerization of hemoglobin S in the absence of crystallization. The action of other kinds of hemoglobin in the molecular aggregate formation process can be explained.   Los mecanismos de formación molecular agregada desempeña un papel importante en la interpretación de la patofisiología de la anemia de células falciformes (o anemia drepanocítica), y en la selección de las estrategias terapéuticas a seguir.  Aquí se propone un mecanismo y un modelo matemático. el modelo postula la existencia de microtúbulos defectivos formados por deoxihemoglobina S y oxihemoglobina S, y explica la dependencia de la polimerización de la concentración de hemoglobina, la temperatura y la presión parcial de oxígeno. El análisis hace énfasis en la polimerización de hemoglobina S en la ausencia de cristalización. La acción de otras clases de hemoglobinas en la formación molecular agregada puede ser explicada

Herramienta computacional para el estudio del ictus cerebral usando mapas de ADC. Evaluación preliminar

Ischemic cerebrovascular disease annually affects 15 million people worldwide, including 5 million deaths and other forms of permanent disability. In some research centers in Cuba new neuroprotective therapies are being developed, so it is essential to study its effect. In this paper the use of digital image processing methods to quantify the apparent diffusion of coefficient maps (ADC) in ischemic patients obtained using weighed MRI diffusion is proposed. The study involved 19 individuals. Of these, 14 had ischemic lesions within the first 12 hours with an age between 29 and 89 years. The other five individuals were healthy subjects aged between 28 and 62 years. A native tool (ADCquant) was developed in Matlab. This software is used to determine ADC maps in three brain regions: the ischemic and contralateral areas and a region of cerebrospinal fluid. The ADC map was useful in quantifying the ischemic areas their mean value was 50.7±8.7*10-5mm2/s. Whereas, the mean in healthy tissue and cerebrospinal fluid was 83.0±9.4*10-5mm2/s,311.4±12.1*10-5mm2/s respectively. Statistical analysis showed significant differences between the three areas. This tool help to manage and quantify ADC maps. Moreover, a first quantification using ADC maps of ischemic patients in Cuba is provided.La enfermedad cerebrovascular isquémica afecta anualmente a 15 millones de personas en  todo el mundo, de  ellas 5 millones mueren y otros quedan con algún tipo de discapacidad permanente. En este trabajo se presenta un estudio descriptivo, observacional y de corte longitudinal, en  pacientes con sospecha de daños isquémicos, entre julio y  agosto del 2012, con el objetivo de determinar valores de los mapas del coeficiente de difusión aparente (ADC) para clasificar los tejidos cerebrales en diferentes zonas. En el estudio participaron 26 individuos, 14 presentan lesiones  isquémicas recientes y la edad comprendida se encuentra entre 29 y 89 años. De los pacientes con lesiones seis son del  sexo masculino y los ocho restantes del sexo femenino. Se utilizaron cinco voluntarios sanos con edades entre 20 y 79 años. Siete pacientes poseen lesiones cerebrales antiguas. De este estudio se obtiene una clasificación de los pacientes en sanos y patológicos según los valores obtenidos del ADC y por edades. El mapa de ADC mostró utilidad en el diagnóstico de zonas afectadas por la disminución de este valor en el tejido isquémico (48.6±10.8)*10-5mm2 /s con respecto al sano (83.0±9.4)*10-5mm2 /s y al líquido cefalorraquídeo (311.4±12.1)  *10-5mm2 /s. Se desarrolló una herramienta autóctona en Matlab  (ADCquant) para el manejo y la cuantificación de los mapas de (ADC). Por primera vez se realiza una clasificación del tejido  cerebral por el valor de ADC

A Mechanism of crystallization process of hemoglobin S

It has been studied as the qualitative consequence of a proposed mechanism of reaction for the formation of HbS molecular aggregations, as well as the mathematical model associated with it, for the particular case that the process of crystallization takes place at partial pressure and constant temperature. It is showed that the results mentioned in the study can be used to explain experimental existing data, although this data are small to decide between various options that are compatible with existing experimental models and experimental data. Also, qualitative consequences of to mechanism of reaction suggested for the formation of HbS molecular aggregations, as well as the mathematical model associated, are studied for a particular case in which to process of crystallization under constant oxygen, partial pressure and constant tem- peratures. The results of such study, which are able to explain the existing experi- mental data, are shown. However, this is latter very scarce for being able to decide among various existing choices compatible with the model and experimental data

A Model of the Molecular Aggregate Processes of Hemoglobin S. Absence of Cristallization

Aquí se propone un mecanismo y un modelo matemático. el modelo postula la existencia de microtúbulos defectivos formados por deoxihemoglobina S y oxihemoglobina S, y explica la dependencia de la polimerización de la concentración de hemoglobina, la temperatura y la presión parcial de oxígeno. El análisis hace énfasis en la polimerización de hemoglobina S en la ausencia de cristalización. La acción de otras clases de hemoglobinas en la formación molecular agregada puede ser explicada

Comportamiento de las trayectorias de un sistema de ecuaciones diferenciales que modela el proceso de polimerizacion de la Hb S como medio de evaluar el estado del paciente con anemia drepanocítica

En el presente trabajo se analizan algunos casos particulares de un sistema de ecuaciones diferenciales que modela la anemia drepanocítica. Se hace un estudio cualitativo del comportamiento de las trayectorias en una vecindad de las posiciones de equilibrio, y se dan conclusiones respecto al posible desarrollo de la enfermedad en correspondencia con la simulación realizada. Se realiza un profundo análisis de los casos críticos mediante la teoría analítica de ecuaciones diferenciales

Bases para un sistema de control remoto de la calidad de equipos de imágenes por resonancia magnética

The medical images systems convert characteristic of the tissues in gray levels or color, using a physical method and a specific mathematical transformation. In Magnetic Resonance Images (MRI) these levels have a multi-parametric dependence, this a reason of their strong presence in the daily clinical practice. This technological complexity, the high costs and the importance that have these study for the patient's life, confer to the Quality Control (QC) human, technological, economic and juridical implications. Several international groups dedicated to the QC in MRI and diversity of approaches to carry out the tests of acceptance and periodic control of the quality exist. The characterization is habitually carried out, with global methods that don't allow a detailed quantitative parametric study. A novel system of quantitative control was developed based on quantitative describers by slices and temporal. This system is formed for: 1) standard methodology of acquisition of the experimental data, 2) subsystem of functions and programs developed in MatLab, 3) subsystem of graphics and reports, and 4) the expert. It is used successfully in the characterization and the periodic control of MRI machines of several magnetic fields in Cuba and in Venezuela. They were defined and established quantitative descriptors for MRI machines. The software flexibility allows carry out the QC to any machine facilitating the standardization and its use in multi-center studies. The retrospective and predictive value of the system was demonstrated. They feel the bases for the remote realization of the test.Los sistemas de imágenes médicas convierten características de los tejidos en niveles de grises o colores, usando un método físico y una transformación matemática específicos. En las Imágenes de Resonancia Magnética (IRM) estos niveles tienen una dependencia multiparamétrica, siendo esta una razón de su fuerte presencia en la práctica clínica diaria. Su complejidad tecnológica, altos costos y la importancia que para la vida del paciente tienen éstos estudios, le confieren al Control y Aseguramiento de la Calidad (CAC) implicaciones humanas, tecnológicas, económicas y jurídicas. Existen grupos internacionales dedicados al CAC en IRM y diversidad de criterios para realizar las pruebas de aceptación y control periódico de la calidad. La caracterización se realiza habitualmente, con métodos globales que no permiten un estudio paramétrico cuantitativo detallado. Se desarrolló un novedoso sistema de control basado en descriptores cuantitativos por planos y descriptores cuantitativos temporales. Este sistema está formado por: 1) metodología estándar de adquisición de los datos experimentales, 2) subsistema de funciones y programas desarrollados en MatLab, 3) subsistema de gráficos e informes y 4) el experto. Se utiliza exitosamente en la caracterización y el control periódico de equipos de varios campos magnéticos en Cuba y en Venezuela. Se definieron y establecieron los descriptores cuantitativos para equipos de IRM. La flexibilidad del software permite realizar el CAC a cualquier equipo facilitando la estandarización y su uso en estudios multicéntricos. El sistema demostró valor retrospectivo y predictivo. Se sientan las bases para la realización remota de los test