Procesamiento y almacenamiento distribuido de imágenes basados en grafos: Aplicación para recuperación de información en imágenes muy grandes

El almacenamiento y tratamiento de señales digitales es un campo muy importante de la informática. Dichas señales contienen información valiosa que ha de ser extrada y transformada para poder ser utilizada. En la presente tesis doctoral se han creado métodos para almacenar, procesar y recuperar información de las regiones contenidas en una imagen, en especial en imágenes de gran tamaño. Como base del trabajo se ha diseñado una estructura de datos de tipo grafo para poder almacenar todas las regiones contenidas en una imagen. En esta estructura de datos se pueden guardar tanto los descriptores de bajo nivel de las regiones como las relaciones estructurales entre las distintas regiones de la imagen. En los sistemas de almacenamiento de imágenes es una práctica habitual distribuir las imágenes para mejorar el rendimiento. Más allá de este tipo de distribución, una característica distintiva y novedosa de la estructura de datos creada en la presente investigación es que puede funcionar de forma distribuida de manera que una imagen grande puede ser dividida en varias subimagenes, y dichas sub-imágenes pueden ser almacenadas de forma separada en varios servidores. También se han adaptado algunos métodos y algoritmos pertenecientes a la Morfología Matemática para trabajar directamente sobre la estructura de datos distribuida. De esta manera, se pueden procesar todas las sub-imágenes de una misma imagen sin necesidad de reconstruir la imagen inicial. Finalmente, haciendo uso de la estructura de datos y de los métodos desarrollados se ha creado un prototipo de sistema multi-agente capaz de almacenar y procesar imágenes grandes. Este prototipo permite realizar consultas para recuperar información perteneciente a regiones de una imagen almacenada en el sistema sin necesidad de volver a ser procesada. En la experimentación realizada, resumida en los resultados presentados, se muestra que la división y distribución de una imagen en varias sub-imágenes reduce los tiempos de almacenamiento, procesamiento y recuperación de la información

Cloud Computing Service for Managing Large Medical Image Data-Sets Using Balanced Collaborative Agents

Managing large medical image collections is an increasingly demanding important issue in many hospitals and other medical settings. A huge amount of this information is daily generated, which requires robust and agile systems. In this paper we present a distributed multi-agent system capable of managing very large medical image datasets. In this approach, agents extract low-level information from images and store them in a data structure implemented in a relational database. The data structure can also store semantic information related to images and particular regions. A distinctive aspect of our work is that a single image can be divided so that the resultant sub-images can be stored and managed separately by different agents to improve performance in data accessing and processing. The system also offers the possibility of applying some region-based operations and filters on images, facilitating image classification. These operations can be performed directly on data structures in the database

Cloud Computing en salud: Sistema para Administrar Imagenes Biomedicas

En el campo de la biomedicina se genera una inmensa cantidad de imágenes diariamente. Para administrarlas es necesaria la creación de sistemas informáticos robustos y ágiles, que necesitan gran cantidad de recursos computacionales. El presente artículo presenta un servicio de cloud computing capaz de manejar grandes colecciones de imágenes biomédicas. Gracias a este servicio organizaciones y usuarios podrían administrar sus imágenes biomédicas sin necesidad de poseer grandes recursos informáticos. El servicio usa un sistema distribuido multi agente donde las imágenes son procesadas y se extraen y almacenan en una estructura de datos las regiones que contiene junto con sus características. Una característica novedosa del sistema es que una misma imagen puede ser dividida, y las sub-imágenes resultantes pueden ser almacenadas por separado por distintos agentes. Esta característica ayuda a mejorar el rendimiento del sistema a la hora de buscar y recuperar las imágenes almacenadas

Supporting patient screening to identify suitable clinical trials.

To support the efficient execution of post-genomic multi-centric clinical trials in breast cancer we propose a solution that streamlines the assessment of the eligibility of patients for available trials. The assessment of the eligibility of a patient for a trial requires evaluating whether each eligibility criterion is satisfied and is often a time consuming and manual task. The main focus in the literature has been on proposing different methods for modelling and formalizing the eligibility criteria. However the current adoption of these approaches in clinical care is limited. Less effort has been dedicated to the automatic matching of criteria to the patient data managed in clinical care. We address both aspects and propose a scalable, efficient and pragmatic patient screening solution enabling automatic evaluation of eligibility of patients for a relevant set of trials. This covers the flexible formalization of criteria and of other relevant trial metadata and the efficient management of these representations

Analysis of the suitability of existing medical ontologies for building a scalable semantic interoperability solution supporting multi-site collaboration in oncology

Semantic interoperability is essential to facilitate efficient collaboration in heterogeneous multi-site healthcare environments. The deployment of a semantic interoperability solution has the potential to enable a wide range of informatics supported applications in clinical care and research both within as ingle healthcare organization and in a network of organizations. At the same time, building and deploying a semantic interoperability solution may require significant effort to carryout data transformation and to harmonize the semantics of the information in the different systems. Our approach to semantic interoperability leverages existing healthcare standards and ontologies, focusing first on specific clinical domains and key applications, and gradually expanding the solution when needed. An important objective of this work is to create a semantic link between clinical research and care environments to enable applications such as streamlining the execution of multi-centric clinical trials, including the identification of eligible patients for the trials. This paper presents an analysis of the suitability of several widely-used medical ontologies in the clinical domain: SNOMED-CT, LOINC, MedDRA, to capture the semantics of the clinical trial eligibility criteria, of the clinical trial data (e.g., Clinical Report Forms), and of the corresponding patient record data that would enable the automatic identification of eligible patients. Next to the coverage provided by the ontologies we evaluate and compare the sizes of the sets of relevant concepts and their relative frequency to estimate the cost of data transformation, of building the necessary semantic mappings, and of extending the solution to new domains. This analysis shows that our approach is both feasible and scalable

Plasma Rich in Growth Factors (PRGF) in Transepithelial Photorefractive Keratectomy (TPRK)

To evaluate the usage of plasma rich in growth factor (PRGF) in transepithelial photorefractive keratectomy (TPRK) in low and moderate myopia, patients who underwent myopic and astigmatism TPRK with PRGF were involved in this retrospective, observational study. Subjects underwent a surgical procedure between February 2019 and June 2019. A three-month follow-up was recorded. Pain score was assessed with a visual analogue scale (0–10) and re-epithelialization time recorded. A total of 48 eyes from 24 patients were recruited. Mean uncorrected distance visual acuity (UDVA) was 20/20.31 (0.00 ± 0.02 LogMAR). A total of 98% of eyes did not change corrected distance visual acuity (CDVA) lines. Two percent of eyes lost one line of CDVA. Preoperative spherical equivalent was −2.67 ± 1.37 D and after three months changed to −0.21 ± 0.34 D, and 2% of eyes changed 0.50 D or more between one and three months. Pain score was 3.29 ± 0.61 (3 to 6) score points at day one and 0.08 ± 0.27 score points at day seven. Finally, re-epithelialization time was 2.50 ± 1.20 days. PRGF addition to conventional refractive treatment such as TPRK seems to alleviate immediate postoperative pain and positively contribute to corneal re-epithelization time.publishersversionPeer reviewe

Accessing and managing open medical resources in Africa over the Internet

Recent commentaries have proposed the advantages of using open exchange of data and informatics resources for improving health-related policies and patient care in Africa. Yet, in many African regions, both private medical and public health information systems are still unaffordable. Open exchange over the social Web 2.0 could encourage more altruistic support of medical initiatives. We have carried out some experiments to demonstrate the feasibility of using this approach to disseminate open data and informatics resources in Africa. After the experiments we developed the AFRICA BUILD Portal, the first Social Network for African biomedical researchers. Through the AFRICA BUILD Portal users can access in a transparent way to several resources. Currently, over 600 researchers are using distributed and open resources through this platform committed to low connections

Potential role of new molecular plasma signatures on cardiovascular risk stratification in asymptomatic individuals

The evaluation of cardiovascular (CV) risk is based on equations derived from epidemiological data in individuals beyond the limits of middle age such as the Framingham and SCORE risk assessments. Lifetime Risk calculator (QRisk®), estimates CV risk throughout a subjects' lifetime, allowing those. A more aggressive and earlier intervention to be identified and offered protection from the consequences of CV and renal disease. The search for molecular profiles in young people that allow a correct stratification of CV risk would be of great interest to adopt preventive therapeutic measures in individuals at high CV risk. To improve the selection of subjects susceptible to intervention with aged between 30-50 years, we have employed a multiple proteomic strategy to search for new markers of early CV disease or reported CV events and to evaluate their relationship with Lifetime Risk. Blood samples from 71 patients were classified into 3 groups according to their CV risk (healthy, with CV risk factors and with a previously reported CV event subjects) and they were analyzed using a high through quantitative proteomics approach. This strategy allowed three different proteomic signatures to be defined, two of which were related to CV stratification and the third one involved markers of organ damage.This work was supported by grants from the Instituto de Salud Carlos III (PI070537, IF08/3667-1, PI11-02239, PI 14/01917, PI11/01401, PI11/02432, PI13/01873, PI13/01746, PI13/01581, PI14/01650, PI14/01841), PT13/0001/0013, PIE13/00051, PIE13/00045, CP09/00229, CP15/00129, IDC Salud (3371/002), the MutuaMadrileña Foundation, the SENEFRO Foundation and FONDOS FEDER (RD06/0014/1015, RD12/0042/0071). Sociedad Española de cardiología para la Investigación Básica 2017. Grant PRB3 (IPT17/0019 - ISCIII-SGEFI / ERDF. These results are in line with the Spanish initiative on the Human Proteome Project.S

Beneficial effect of ursodeoxycholic acid in patients with acyl-CoA oxidase 2 (ACOX2) deficiency-associated hypertransaminasemia

Background and aims: A variant (p.Arg225Trp) of peroxisomal acyl-CoA oxidase 2 (ACOX2), involved in bile acid (BA) side-chain shortening, has been associated with unexplained persistent hypertransaminasemia and accumulation of C27-BAs, mainly 3?,7?,12?-trihydroxy-5?-cholestanoic acid (THCA). We aimed to investigate the prevalence of ACOX2 deficiency-associated hypertransaminasemia (ADAH), its response to ursodeoxycholic acid (UDCA), elucidate its pathophysiological mechanism and identify other inborn errors that could cause this alteration. Methods and results: Among 33 patients with unexplained hypertransaminasemia from 11 hospitals and 13 of their relatives, seven individuals with abnormally high C27-BA levels (>50% of total BAs) were identified by high-performance liquid chromatography-mass spectrometry. The p.Arg225Trp variant was found in homozygosity (exon amplification/sequencing) in two patients and three family members. Two additional nonrelated patients were heterozygous carriers of different alleles: c.673C>T (p.Arg225Trp) and c.456_459del (p.Thr154fs). In patients with ADAH, impaired liver expression of ACOX2, but not ACOX3, was found (immunohistochemistry). Treatment with UDCA normalized aminotransferase levels. Incubation of HuH-7 hepatoma cells with THCA, which was efficiently taken up, but not through BA transporters, increased reactive oxygen species production (flow cytometry), endoplasmic reticulum stress biomarkers (GRP78, CHOP, and XBP1-S/XBP1-U ratio), and BAX? expression (reverse transcription followed by quantitative polymerase chain reaction and immunoblot), whereas cell viability was decreased (tetrazolium salt-based cell viability test). THCA-induced cell toxicity was higher than that of major C24-BAs and was not prevented by UDCA. Fourteen predicted ACOX2 variants were generated (site-directed mutagenesis) and expressed in HuH-7 cells. Functional tests to determine their ability to metabolize THCA identified six with the potential to cause ADAH. Conclusions: Dysfunctional ACOX2 has been found in several patients with unexplained hypertransaminasemia. This condition can be accurately identified by a noninvasive diagnostic strategy based on plasma BA profiling and ACOX2 sequencing. Moreover, UDCA treatment can efficiently attenuate liver damage in these patients.Funding information: This study was supported by the following grants: CIBERehd (EHD15PI05/2016); Fondo de Investigaciones Sanitarias, Instituto de Salud Carlos III, Spain (PI19/00819 and PI20/00189), co-funded by European Regional Development Fund/European Social Fund, “Investing in your future”; “Junta de Castilla y León” (SA074P20); Fundació Marato TV3 (201916–31); AECC Scientific Foundation (2017/2020), Spain; and “Centro Internacional sobre el Envejecimiento” (OLD-HEPAMARKER, 0348_CIE_6_E), Spain. We also acknowledge support from grants PID2019-111669RBI-100, PID2020-115055RB-I00 from Plan Nacional de I+D funded by the “Agencia Estatal de Investigación” (AEI) and the center grant P50AA011999 Southern California Research Center for ALPD and Cirrhosis funded by NIAAA/NIH, as well as support from AGAUR of the “Generalitat de Catalunya” SGR-2017-1112, European Cooperation in Science & Technology (COST) ACTION CA17112 Prospective European Drug-Induced Liver Injury Network. Marta Alonso-Peña was the recipient of a predoctoral fellowship from “Ministerio de Educación, Cultura y Deporte” (BOE-A-2015-9456; FPU-14/00214) and a Mobility Grant for Short Stays from “Ministerio de Ciencia, Innovación y Universidades” (EST17/00186). Ricardo Espinosa-Escudero is the recipient of a predoctoral fellowship from “Junta de Castilla y León” and “Fondo Social Europeo” (EDU/574/2018). The funding sources were not involved in the research design or preparation of the article

Assessment of platelet REACtivity after transcatheter aortic valve replacement

OBJECTIVES: The REAC-TAVI (Assessment of platelet REACtivity after Transcatheter Aortic Valve Implantation) trial enrolled patients with aortic stenosis (AS) undergoing transcatheter aortic valve replacement (TAVR) pre-treated with aspirin + clopidogrel, aimed to compare the efficacy of clopidogrel and ticagrelor in suppressing high platelet reactivity (HPR) after TAVI. BACKGROUND: Current recommendations support short-term use of aspirin + clopidogrel for patients with severe AS undergoing TAVR despite the lack of compelling evidence. METHODS: This was a prospective, randomized, multicenter investigation. Platelet reactivity was measured at 6 different time points with the VerifyNow assay (Accriva Diagnostics, San Diego, California). HPR was defined as (P2Y12 reaction units (PRU) ≥208. Patients with HPR before TAVR were randomized to either aspirin + ticagrelor or aspirin + clopidogrel for 3 months. Patients without HPR continued with aspirin + clopidogrel (registry cohort). The primary endpoint was non-HPR status (PRU <208) in ≥70% of patients treated with ticagrelor at 90 days post-TAVR. RESULTS: A total of 68 patients were included. Of these, 48 (71%) had HPR (PRU 273 ± 09) and were randomized to aspirin + ticagrelor (n = 24, PRU 277 ± 08) or continued with aspirin + clopidogrel (n = 24, PRU 269 ± 49). The remaining 20 patients (29%) without HPR (PRU 133 ± 12) were included in the registry. Overall, platelet reactivity across all the study time points after TAVR was lower in patients randomized to ticagrelor compared with those treated with clopidogrel, including those enrolled in the registry (p < 0.001). The primary endpoint was achieved in 100% of patients with ticagrelor compared with 21% with clopidogrel (p < 0.001). Interestingly, 33% of clopidogrel responder patients at baseline developed HPR status during the first month after TAVR. CONCLUSIONS: HPR to clopidogrel is present in a considerable number of patients with AS undergoing TAVR. Ticagrelor achieves a better and faster effect, providing sustained suppression of HPR to these patients. (Platelet Reactivity After TAVI: A Multicenter Pilot Study [REAC-TAVI]; NCT02224066)