Long-term mortality prediction after operations for type A ascending aortic dissection

<p>Abstract</p> <p>Background</p> <p>There are few long-term mortality prediction studies after acute aortic dissection (AAD) Type A and none were performed using new models such as neural networks (NN) or support vector machines (SVM) which may show a higher discriminatory potency than standard multivariable models.</p> <p>Methods</p> <p>We used 32 risk factors identified by Literature search and previously assessed in short-term outcome investigations. Models were trained (50%) and validated (50%) on 2 random samples from a consecutive 235-patient cohort. NN were run only on patients with complete data for all included variables (N = 211); SVM on the overall group. Discrimination was assessed by receiver operating characteristic area under the curve (AUC) and Gini's coefficients along with classification performance.</p> <p>Results</p> <p>There were 84 deaths (36%) occurring at 564 ± 48 days (95%CI from 470 to 658 days). Patients with complete variables had a slightly lower death rate (60 of 211, 28%). NN classified 44 of 60 (73%) dead patients and 147 of 151 (97%) long-term survivors using 5 covariates: immediate post-operative chronic renal failure, circulatory arrest time, the type of surgery on ascending aorta plus hemi-arch, extracorporeal circulation time and the presence of Marfan habitus. Global accuracies of training and validation NN were excellent with AUC respectively 0.871 and 0.870 but classification errors were high among patients who died. Training SVM, using a larger number of covariates, showed no false negative or false positive cases among 118 randomly selected patients (error = 0%, AUC 1.0) whereas validation SVM, among 117 patients, provided 5 false negative and 11 false positive cases (error = 22%, AUC 0.821, p < 0.01 versus NN results). An html file was produced to adopt and manipulate the selected parameters for practical predictive purposes.</p> <p>Conclusions</p> <p>Both NN and SVM accurately selected a few operative and immediate post-operative factors and the Marfan habitus as long-term mortality predictors in AAD Type A. Although these factors were not new per se, their combination may be used in practice to index death risk post-operatively with good accuracy.</p

Artificial Neural Networks Versus Multiple Logistic Regression to Predict 30-Day Mortality After Operations For Type A Ascending Aortic Dissection§

There are few comparative reports on the overall accuracy of neural networks (NN), assessed only versus multiple logistic regression (LR), to predict events in cardiovascular surgery studies and none has been performed among acute aortic dissection (AAD) Type A patients. OBJECTIVES: We aimed at investigating the predictive potential of 30-day mortality by a large series of risk factors in AAD Type A patients comparing the overall performance of NN versus LR. METHODS: We investigated 121 plus 87 AAD Type A patients consecutively operated during 7 years in two Centres. Forced and stepwise NN and LR solutions were obtained and compared, using receiver operating characteristic area under the curve (AUC) and their 95% confidence intervals (CI) and Gini's coefficients. Both NN and LR models were re-applied to data from the second Centre to adhere to a methodological imperative with NN. RESULTS: Forced LR solutions provided AUC 87.9+/-4.1% (CI: 80.7 to 93.2%) and 85.7+/-5.2% (CI: 78.5 to 91.1%) in the first and second Centre, respectively. Stepwise NN solution of the first Centre had AUC 90.5+/-3.7% (CI: 83.8 to 95.1%). The Gini's coefficients for LR and NN stepwise solutions of the first Centre were 0.712 and 0.816, respectively. When the LR and NN stepwise solutions were re-applied to the second Centre data, Gini's coefficients were, respectively, 0.761 and 0.850. Few predictors were selected in common by LR and NN models: the presence of pre-operative shock, intubation and neurological symptoms, immediate post-operative presence of dialysis in continuous and the quantity of post-operative bleeding in the first 24 h. The length of extracorporeal circulation, post-operative chronic renal failure and the year of surgery were specifically detected by NN. CONCLUSIONS: Different from the International Registry of AAD, operative and immediate post-operative factors were seen as potential predictors of short-term mortality. We report a higher overall predictive accuracy with NN than with LR. However, the list of potential risk factors to predict 30-day mortality after AAD Type A by NN model is not enlarged significantly

Programmable Ligand Detection System in Plants through a Synthetic Signal Transduction Pathway

There is an unmet need to monitor human and natural environments for substances that are intentionally or unintentionally introduced. A long-sought goal is to adapt plants to sense and respond to specific substances for use as environmental monitors. Computationally re-designed periplasmic binding proteins (PBPs) provide a means to design highly sensitive and specific ligand sensing capabilities in receptors. Input from these proteins can be linked to gene expression through histidine kinase (HK) mediated signaling. Components of HK signaling systems are evolutionarily conserved between bacteria and plants. We previously reported that in response to cytokinin-mediated HK activation in plants, the bacterial response regulator PhoB translocates to the nucleus and activates transcription. Also, we previously described a plant visual response system, the de-greening circuit, a threshold sensitive reporter system that produces a visual response which is remotely detectable and quantifiable.We describe assembly and function of a complete synthetic signal transduction pathway in plants that links input from computationally re-designed PBPs to a visual response. To sense extracellular ligands, we targeted the computational re-designed PBPs to the apoplast. PBPs bind the ligand and develop affinity for the extracellular domain of a chemotactic protein, Trg. We experimentally developed Trg fusions proteins, which bind the ligand-PBP complex, and activate intracellular PhoR, the HK cognate of PhoB. We then adapted Trg-PhoR fusions for function in plants showing that in the presence of an external ligand PhoB translocates to the nucleus and activates transcription. We linked this input to the de-greening circuit creating a detector plant.Our system is modular and PBPs can theoretically be designed to bind most small molecules. Hence our system, with improvements, may allow plants to serve as a simple and inexpensive means to monitor human surroundings for substances such as pollutants, explosives, or chemical agents

Evidence-based Kernels: Fundamental Units of Behavioral Influence

This paper describes evidence-based kernels, fundamental units of behavioral influence that appear to underlie effective prevention and treatment for children, adults, and families. A kernel is a behavior–influence procedure shown through experimental analysis to affect a specific behavior and that is indivisible in the sense that removing any of its components would render it inert. Existing evidence shows that a variety of kernels can influence behavior in context, and some evidence suggests that frequent use or sufficient use of some kernels may produce longer lasting behavioral shifts. The analysis of kernels could contribute to an empirically based theory of behavioral influence, augment existing prevention or treatment efforts, facilitate the dissemination of effective prevention and treatment practices, clarify the active ingredients in existing interventions, and contribute to efficiently developing interventions that are more effective. Kernels involve one or more of the following mechanisms of behavior influence: reinforcement, altering antecedents, changing verbal relational responding, or changing physiological states directly. The paper describes 52 of these kernels, and details practical, theoretical, and research implications, including calling for a national database of kernels that influence human behavior

The replication of Bangladeshi H9N2 avian influenza viruses carrying genes from H7N3 in mammals

H9N2 avian influenza viruses are continuously monitored by the World Health Organization because they are endemic; they continually reassort with H5N1, H7N9 and H10N8 viruses; and they periodically cause human infections. We characterized H9N2 influenza viruses carrying internal genes from highly pathogenic H7N3 viruses, which were isolated from chickens or quail from live-bird markets in Bangladesh between 2010 and 2013. All of the H9N2 viruses used in this study carried mammalian host-specific mutations. We studied their replication kinetics in normal human bronchoepithelial cells and swine tracheal and lung explants, which exhibit many features of the mammalian airway epithelium and serve as a mammalian host model. All H9N2 viruses replicated to moderate-to-high titers in the normal human bronchoepithelial cells and swine lung explants, but replication was limited in the swine tracheal explants. In Balb/c mice, the H9N2 viruses were nonlethal, replicated to moderately high titers and the infection was confined to the lungs. In the ferret model of human influenza infection and transmission, H9N2 viruses possessing the Q226L substitution in hemagglutinin replicated well without clinical signs and spread via direct contact but not by aerosol. None of the H9N2 viruses tested were resistant to the neuraminidase inhibitors. Our study shows that the Bangladeshi H9N2 viruses have the potential to infect humans and highlights the importance of monitoring and characterizing this influenza subtype to better understand the potential risk these viruses pose to humans

Serum levels of fibroblast growth factor-2 distinguish Takayasu arteritis from giant cell arteritis independent of age at diagnosis

Takayasu arteritis (TAK) and giant cell arteritis (GCA) are two major variants of large vessel vasculitis, and age is a major factor in their differential diagnosis. We sought to determine whether the two diseases exist on the same spectrum. We compared the serum levels of multiple cytokines and chemokines in 25 patients with TAK, 20 patients with GCA, and sex- and age-matched healthy donors for either condition (HD-TAK and HD-GCA). To evaluate the effects of age on the levels of cytokines and chemokines, we performed multiple logistic regression analysis using the least absolute shrinkage and selection operator (LASSO) method. The levels of IL-1RA, IL-10, GM-CSF, G-CSF, FGF-2, eotaxin, and IP-10 were significantly different between TAK and GCA, but no differences were found in the levels of IL-6, IL-12(p40), IL-17, IFN-γ, and TNF-α. Significant differences in the levels of IL-1RA, IL-10, GM-CSF, eotaxin,and IP-10 were observed between the HD-TAK and HD-GCA groups. Multiple logistic regression analysis demonstrated that only FGF-2 and IP-10 could significantly distinguish the diseases when added to age. Multiple logistic analysis using factors selected by the LASSO method revealed that FGF-2 was the only significant factor to distinguish the diseases when added to age. Among numerous cytokines and chemokines analyzed, only FGF-2 could be used together with age at diagnosis to differentiate TAK and GCA.Our results suggested the importance of considering the effects of age on serum cytokines

Lesões complexas supra-aórticas de arterite de Takayasu: como tratá-las? Complex supraaortic lesions in Takayasu arteritis: how to treat them?

Submitted by Guilherme Lemeszenski ([email protected]) on 2013-08-22T18:43:27Z No. of bitstreams: 1 S1677-54492009000400011.pdf: 300056 bytes, checksum: 1ded24802663aa4f16106628bd9c984d (MD5)Made available in DSpace on 2013-08-22T18:43:27Z (GMT). No. of bitstreams: 1 S1677-54492009000400011.pdf: 300056 bytes, checksum: 1ded24802663aa4f16106628bd9c984d (MD5) Previous issue date: 2009-12-01Made available in DSpace on 2013-09-30T19:31:06Z (GMT). No. of bitstreams: 2 S1677-54492009000400011.pdf: 300056 bytes, checksum: 1ded24802663aa4f16106628bd9c984d (MD5) S1677-54492009000400011.pdf.txt: 20388 bytes, checksum: cf2bcb70182d3613034a836a9dc88472 (MD5) Previous issue date: 2009-12-01Submitted by Vitor Silverio Rodrigues ([email protected]) on 2014-05-20T15:08:32Z No. of bitstreams: 2 S1677-54492009000400011.pdf: 300056 bytes, checksum: 1ded24802663aa4f16106628bd9c984d (MD5) S1677-54492009000400011.pdf.txt: 20388 bytes, checksum: cf2bcb70182d3613034a836a9dc88472 (MD5)Made available in DSpace on 2014-05-20T15:08:32Z (GMT). No. of bitstreams: 2 S1677-54492009000400011.pdf: 300056 bytes, checksum: 1ded24802663aa4f16106628bd9c984d (MD5) S1677-54492009000400011.pdf.txt: 20388 bytes, checksum: cf2bcb70182d3613034a836a9dc88472 (MD5) Previous issue date: 2009-12-01Universidade Estadual Paulista Faculdade de Medicina de BotucatuUNESP Faculdade de Medicina de BotucatuAugusta Hospital Serviço de Cirurgia Vascular e EndovascularAngiocenterSanta Casa de São José dos Campos Serviço de Cirurgia VascularUniversidade Estadual Paulista Faculdade de Medicina de BotucatuUNESP Faculdade de Medicina de Botucat