RESUMEN
Patient-specific cardiac modeling can help in understanding pathophysiology and therapy planning. However it requires to combine functional and anatomical data in order to build accurate models and to personalize the model geometry, kinematics, electrophysiology and mechanics. Personalizing the electromechanical coupling from medical images is a challenging task. We use the Bestel-Clément-Sorine (BCS) electromechanical model of the heart, which provides reasonable accuracy with a reasonable number of parameters (14 for each ventricle) compared to the available clinical data at the organ level. We propose a personalization strategy from cine MRI data in two steps. We first estimate global parameters with an automatic calibration algorithm based on the Unscented Transform which allows to initialize the parameters while matching the volume and pressure curves. In a second step we locally personalize the contractilities of all AHA (American Heart Association) zones of the left ventricle using the reduced order unscented Kalman filtering on Regional Volumes. This personalization strategy was validated synthetically and tested successfully on eight healthy and three pathological cases.
Asunto(s)
Sistema de Conducción Cardíaco/fisiología , Ventrículos Cardíacos/anatomía & histología , Interpretación de Imagen Asistida por Computador/métodos , Imagen por Resonancia Cinemagnética/métodos , Modelos Cardiovasculares , Contracción Miocárdica/fisiología , Función Ventricular Izquierda/fisiología , Algoritmos , Simulación por Computador , Acoplamiento Excitación-Contracción/fisiología , Humanos , Aumento de la Imagen/métodos , Imagenología Tridimensional/métodos , Tamaño de los Órganos , Medicina de Precisión/métodos , Reproducibilidad de los Resultados , Sensibilidad y EspecificidadAsunto(s)
Vasos Sanguíneos/patología , Neoplasias Encefálicas/genética , Neoplasias del Sistema Nervioso Central/genética , Hemangioma Cavernoso del Sistema Nervioso Central/genética , Proteínas Asociadas a Microtúbulos/genética , Mutación/genética , Neoplasias Primarias Múltiples/genética , Paraparesia/genética , Proteínas Proto-Oncogénicas/genética , Neoplasias de la Médula Espinal/genética , Médula Espinal/patología , Femenino , Humanos , MasculinoRESUMEN
The taxonomic and phylogenetic relationships of Trypanosoma vivax are controversial. It is generally suggested that South American, and East and West African isolates could be classified as subspecies or species allied to T. vivax. This is the first phylogenetic study to compare South American isolates (Brazil and Venezuela) with West/East African T. vivax isolates. Phylogeny using ribosomal sequences positioned all T. vivax isolates tightly together on the periphery of the clade containing all Salivarian trypanosomes. The same branching of isolates within T. vivax clade was observed in all inferred phylogenies using different data sets of sequences (SSU, SSU plus 5.8S or whole ITS rDNA). T. vivax from Brazil, Venezuela and West Africa (Nigeria) were closely related corroborating the West African origin of South American T. vivax, whereas a large genetic distance separated these isolates from the East African isolate (Kenya) analysed. Brazilian isolates from cattle asymptomatic or showing distinct pathology were highly homogeneous. This study did not disclose significant polymorphism to separate West African and South American isolates into different species/subspecies and indicate that the complexity of T. vivax in Africa and of the whole subgenus Trypanosoma (Duttonella) might be higher than previously believed.
Asunto(s)
ADN Protozoario/análisis , Filogenia , Polimorfismo Genético , Trypanosoma vivax/clasificación , Trypanosoma vivax/genética , África , Animales , Secuencia de Bases , Bovinos , ADN Ribosómico/análisis , ADN Ribosómico/química , Geografía , Datos de Secuencia Molecular , Reacción en Cadena de la Polimerasa , Alineación de Secuencia , Ovinos , América del SurRESUMEN
In this study we employed randomly amplified polymorphic DNA patterns to assess the genetic relatedness among 14 Brazilian Trypanosoma evansi stocks from domestic and wild hosts, which are known to differ in biological characteristics. These akinetoplastic stocks were compared with one another, to three Old World (Ethiopia, China and Philippines) dyskinetoplastic stocks of T. evansi, and also with Trypanosoma equiperdum, Trypanosoma brucei brucei, Trypanosoma brucei gambiense and Trypanosoma brucei rhodesiense. Randomly amplified polymorphic DNA analysis showed limited heterogeneity in T. evansi stocks from different hosts and geographical regions of the world, or in other species of the subgenus Trypanozoon. However, minor variations generated random amplification of polymorphic DNA analysis disclosed a pattern consisting of a unique synapomorphic DNA fragment (termed Te664) for the T. evansi cluster that was not detected in any other trypanosome species investigated. Pulsed field gel electrophoresis analysis demonstrated that the Te664 fragment is a repetitive sequence, dispersed in intermediate and minichromosomes of T. evansi. Based on this sequence, we developed a conventional PCR assay for the detection of T. evansi using crude preparations of blood collected either on glass slides or on filter paper as template DNA. Our results showed that this assay may be useful as a diagnostic tool for field-epidemiological studies of T. evansi.
Asunto(s)
ADN Protozoario/genética , Trypanosoma/genética , Animales , Secuencia de Bases , Southern Blotting , Brasil , Búfalos , Carnívoros , Bovinos , ADN Protozoario/química , Perros , Electroforesis en Gel de Campo Pulsado , Variación Genética , Caballos , Datos de Secuencia Molecular , Reacción en Cadena de la Polimerasa , Técnica del ADN Polimorfo Amplificado Aleatorio , Roedores , Homología de Secuencia de Ácido Nucleico , Especificidad de la Especie , Porcinos , Trypanosoma/química , Trypanosoma/aislamiento & purificaciónRESUMEN
The sequence of the spliced-leader gene repeat of a Brazilian Trypanosoma vivax stock from cattle showed high similarity to sequences of West African T. vivax in both intron and intergenic sequences. This is the first evidence based on DNA sequences of close-relatedness between Brazilian and West African T. vivax stocks. A T. vivax-specific diagnostic PCR assay based on spliced-leader gene intergenic sequences was able to amplify DNA from T. vivax stocks from South America (Brazil, Bolivia, and Colombia) and West Africa. Species-specificity of this method was confirmed by results obtained by testing 15 other trypanosomes, including other species and subspecies that can also infect cattle. The PCR assay developed presented high sensitivity, detecting the DNA content of only one parasite and also revealing T. vivax infection in asymptomatic animals without detectable parasitemia by microhematocrit or in Giemsa-stained blood smears. Use of crude preparations from field-blood samples collected on both filter paper and glass slides as DNA template suggested that this method could be useful for the diagnosis of T. vivax in large epidemiological studies.
Asunto(s)
ADN Intergénico/genética , ADN Protozoario/genética , ARN Lider Empalmado/genética , Trypanosoma vivax/genética , Animales , Secuencia de Bases , Brasil , Bovinos , Sondas de ADN/normas , ADN Intergénico/química , ADN Protozoario/química , Ratones , Datos de Secuencia Molecular , Reacción en Cadena de la Polimerasa , Sensibilidad y Especificidad , Alineación de Secuencia , Ovinos , Especificidad de la Especie , Trypanosoma vivax/clasificaciónRESUMEN
The kinetoplast DNA (kDNA) minicircle molecules of 14 Brazilian stocks of Trypanosoma evansi were studied by morphological approaches (Giemsa and 4'-6'-diamidino-2-phenylindole staining and transmission electron microscopy) and molecular approaches (probing with an oligonucleotide complementary to the minicircle origin of replication and polymerase chain reaction amplification of a minicircle sequence). All methods indicated the absence of both a typical kinetoplast and kDNA minicircles, even in a very small number of parasites of a single stock or in small numbers of copies of molecules per cell. We did not detect any altered kDNA molecules. There were no kDNA molecules in either old or new stocks of T. evansi maintained by successive passages in mice. Similarly, no kDNA minicircles were detected in trypanosomes in blood smears from naturally infected domestic and wild animals. Thus, the total absence of kDNA in Brazilian stocks of T. evansi from both domestic and wild mammals is probably the natural state of Brazilian T. evansi.