Academic literature on the topic 'Biomediacal'

Introduction: New approaches to efficient compression and digital processing of audio signals are relevant today. Thereis a lot of interest to new pattern recognition methods which can improve the quality of acoustic anomaly detection. Purpose:Comparative analysis of methods for time-frequency transformation of audio signal patterns, including non-stationary quasiperiodicbiomedical signals in the problem of acoustic anomaly detection. Results: The study compared different time-frequencytransforms (such as windowed Fourier, Gabor, Wigner, pseudo Wigner, smoothed pseudo Wigner, Choi — Williams, Bertrand, pseudoBertrand, smoothed pseudo Bertrand, and wavelet transforms) based on systematization of their functional characteristics(such as the existence and limitedness of basis functions, presence of zero moments and biorthogonal form, opportunity oftwo-dimensional representation and inverse transformation, real time processing, time-frequency transform quality, controlof time-frequency definition, time and frequency interference suppression, relative computational complexity, fast algorithmimplementation) for the problem of biomedial signal pattern recognition. A comparative table is presented with estimates ofinformation capacity for the considered time-frequency transforms. Practical relevance: The proposed approach can solve someacoustic anomaly detection algorithm implementation problems common in non-stationary quasi-periodic processes, in order tostudy disruptive effects causing a change in the functional state of ergatic system operators.

Abstract Graft versus host disease (GvHD) is the most common adverse event after allogeneic bone marrow transplant (BMT). GvHD and the immunosuppression required to treat it limit the desired graft versus leukemic effect and are associated with significant morbidity and mortality. A treatment that selectively controls the harmful immune response during GvHD, without compromising the response to pathogens or tumors, would be transformative. Previously, we demonstrated that mice deficient in Drak2 (Drak2−/−) are resistant to disease in multiple models of T cell-mediated autoimmunity but maintain effective responses to pathogens and tumors. Since similar immune pathologies mediate GvHD and autoimmunity, we sought to investigate whether loss of Drak2 reduced GvHD, while maintaining effective immunity to pathogens. Thus, we utilized a murine model of acute GvHD (aGvHD) in which lethally irradiated mice received MHC-mismatched bone marrow and purified T cells that were either Drak2+/+ or Drak2−/−. We found that mice given MHC-mismatched bone marrow along with Drak2−/− T cells had less severe aGvHD compared to mice receiving Drak2+/+ T cells, as demonstrated by lower clinical scores. Interestingly, mice given Drak2−/− T cells along with MHC-mismatched bone marrow had increased proportions of regulatory T cells and decreased effector T cells compared to mice given wildtype T cells. These data suggest that Drak2 expression within T cells contributes to GvHD development, and therefore is a promising target in the treatment of GvHD. Ongoing studies are investigating whether the absence of Drak2 influences the effective repopulation of a functional immune system following BMT. Funding provided by ALSAC and the St. Jude Graduate School of Biomedial Sciences

Abstract Introduction: Sepsis associated coagulopathy (SAC) is commonly seen in patients which eventually leads to dysfunctional hemostasis and disseminated intravascular coagulation (DIC). Thrombin generation plays an important role in the overall pathophysiology of this process. Previous studies have reported an increase in thrombin generation markers such as thrombin antithrombin complex (TAT) and prothrombin fragment (F1.2). (Hoppensteadt et al. Clin Appl Thromb Hemost. 2014 Mar;20(2):129-35). Sepsis eventually results in consumption coagulopathy in which some of the clotting factors are consumed. The purpose of this study is to determine the thrombin generation potential of baseline blood samples obtained from sepsis associated coagulopathy patients and demonstrate their relevance to thrombin generation markers. Materials and Methods: Baseline citrated blood samples were prospectively collected from 49 patients with sepsis and suspected DIC. DIC scores were determined according to the ISTH scoring system (PTINR, fibrinogen, D-dimer and platelet count). Healthy control (n=50) represented citrated plasma obtained from a commercial supplier (George King Biomediacl, Overland Park, KS). Thrombin generation studies were carried out using a commercially available florigenic substrate methods with thrombin calibrator and PPP reagent (calibrated automated thrombogram; CAT). Such parameters as peak thrombin, lag time and area under the curve were compiled. TAT and F1.2 were measured using commercially available ELISA methods (Seimens, Indianpolis, IN). Functional antithrombin levels were measured using a chromogenic substrate method. All results were calculated in terms of mean ± SD. Applicable statistical methods were used to correlate the thrombin generation parameters with thrombin generation markers and antithrombin. Results: The peak thrombin levels were lower (82±40nM) in the SAC patients in comparison to higher levels observed in the normal plasma (133±10nM). The AUC was lower (561 ±280) in the SAC group in comparison to the normal (624±18). The SAC group showed much longer lag time (4.1±2.1) in comparison to the normal (2.1 ± 2.2). Wide variations in the results were observed in these parameters in the SAC group. The compsoite data is compiled in the table. the F1.2 levels in the DIC group were much higher (570±48 pmol) in comparison to the normal (210±25 pmol). The TAT levels also increased in the SAC group (27.9 ±5.1 ng/ml) in comparison to the normal (2.8 ±0.8 ng/ml). The functional antithrombin levels were decreased in the SAC group (64 ±11%). No correlation was observed between thrombin generation parameters and thrombin generation markers. Conclusion: These results validate the earlier observations that thrombin generation such as F1.2 and TAT are decreased in patients with SAC. However thrombin generation parameters are significantly elevated in this group in comparison to normals. This may be due to the consumption of prothrombin due to the activation of the coagulation system. The SAC group also showed wide variations in both the thrombin generation parameters and the F1.2 and TAT. These variations may be due to the differences in the endogenous pathophysiology state in the SAC patients. The decreased functional AT levels observed in the SAC group are due to the formation of the complex between generated thrombin and antithrombin. Simultaneous profiling of thrombin generation and thrombin generation markers may be helpful in the risk stratification of these patients. Table. Table. Disclosures No relevant conflicts of interest to declare.

Abstract Background Meta-analyses of randomised controlled trials (RCT) have shown the efficacy of pharmacologic lowering of blood pressure (BP) in reducing cardiovascular disease (CVD) risk. While efficacy has been shown across important patient characteristics, meta-analysis based on aggregate data could not fully account for potential sources of variation due to individual-level characteristics. Moreover, it is unclear if any variation in treatment effects due to patient characteristics are reflected in differential effects of BP-lowering treatment on long-term BP according to these characteristics. Purpose We determined the effects of BP-lowering treatment on repeated measures of blood pressure, identified trial- and participant-level sources of heterogeneity, and examined consistency of these BP-lowering effects across different patient characteristics. Methods We conducted an individual patient-level data meta-analysis (N=50 trials) using one-stage approach. We classified trials according to trial design: drug comparison (N=28), placebo-controlled (N=21) and BP-lowering intensity (N=8) trials. We fitted mixed models with fixed treatment effects and fixed time effect, random intercepts at trial and participant level, and a random slope for time at participant level. We adjusted for age, sex and baseline BP (except when used as stratification factor). We used likelihood ratio test and Akaike information criterion to compare models. Results This meta-analysis included 334,219 (42% women) participants. At baseline, mean age=65 (SD=9) years, among whom 18% were current smokers, 47% had cardiovascular disease, 29% had diabetes, and 73% were previously on BP-lowering medication. Participants had an average of 8 BP measurements over 4 years of mean follow-up. For drug comparison trials, mean differences (95% confidence interval) in systolic BP (SBP) and diastolic BP (DBP) between comparison arms were 1.3 (1.2 to 1.3) mmHg and 0.5 (0.5 to 0.5) mmHg, respectively; for placebo-controlled trials, the SBP and DBP differences were 4.2 (4.0 to 4.3) mmHg and 1.9 (1.9 to 2.0) mmHg, respectively; and for BP-lowering intensity trials, the SBP and DBP differences were 8.2 (8.0 to 8.4) mmHg and 3.7 (3.6 to 3.9) mmHg, respectively. However, BP reduction differed by duration of follow-up, type of trial. In particular, for placebo-controlled and BP-intensity trials, heterogeneity in BP reductions according to patient characteristics such as baseline BP, age, sex, prior CVD, diabetes and non-randomised anti-hypertensive use were observed. Conclusion This study shows the role of pharmacologic agents in effectively reducing long-term BP across individuals with a wide range of characteristics. The magnitude of BP reduction varied by several patient characteristics. This might have implications for investigation and explanation of any differential effects of BP treatment on major clinical outcomes. Funding Acknowledgement Type of funding source: Public Institution(s). Main funding source(s): British Heart Foundation; NIHR Oxford Biomedial Research Centre

In recent years, computer advances have changed the way the science progresses and have boosted studies in silico; as a result, the concept of “scientific research” in bioinformatics has quickly changed shifting from the idea of a local laboratory activity towards Web applications and databases provided over the network as services. Thus, biologists have become among the largest beneficiaries of the information technologies, reaching and surpassing the traditional ICT users who operate in the field of so-called "hard science" (i.e., physics, chemistry, and mathematics). Nevertheless, this evolution has to deal with several aspects (including data deluge, data integration, and scientific collaboration, just to cite a few) and presents new challenges related to the proposal of innovative approaches in the wide scenario of emergent ICT solutions. This thesis aims at facing these challenges in the context of three case studies, being each case study devoted to cope with a specific open issue by proposing proper solutions in line with recent advances in computer science. The first case study focuses on the task of unearthing and integrating information from different web resources, each having its own organization, terminology and data formats in order to provide users with flexible environment for accessing the above resources and smartly exploring their content. The study explores the potential of cloud paradigm as an enabling technology to severely curtail issues associated with scalability and performance of applications devoted to support the above task. Specifically, it presents Biocloud Search EnGene (BSE), a cloud-based application which allows for searching and integrating biological information made available by public large-scale genomic repositories. BSE is publicly available at: http://biocloud-unica.appspot.com/. The second case study addresses scientific collaboration on the Web with special focus on building a semantic network, where team members, adequately supported by easy access to biomedical ontologies, define and enrich network nodes with annotations derived from available ontologies. The study presents a cloud-based application called Collaborative Workspaces in Biomedicine (COWB) which deals with supporting users in the construction of the semantic network by organizing, retrieving and creating connections between contents of different types. Public and private workspaces provide an accessible representation of the collective knowledge that is incrementally expanded. COWB is publicly available at: http://cowb-unica.appspot.com/. Finally, the third case study concerns the knowledge extraction from very large datasets. The study investigates the performance of random forests in classifying microarray data. In particular, the study faces the problem of reducing the contribution of trees whose nodes are populated by non-informative features. Experiments are presented and results are then analyzed in order to draw guidelines about how reducing the above contribution. With respect to the previously mentioned challenges, this thesis sets out to give two contributions summarized as follows. First, the potential of cloud technologies has been evaluated for developing applications that support the access to bioinformatics resources and the collaboration by improving awareness of user's contributions and fostering users interaction. Second, the positive impact of the decision support offered by random forests has been demonstrated in order to tackle effectively the curse of dimensionality.