947 resultados para stochastic search variable selection
Resumo:
Objectives We evaluated demographic, clinical, and angiographic factors influencing the selection of coronary artery bypass graft (CABG) surgery versus percutaneous coronary intervention (PCI) in diabetic patients with multivessel coronary artery disease (CAD) in the BARI 2D (Bypass Angioplasty Revascularization Investigation in Type 2 Diabetes) trial. Background Factors guiding selection of mode of revascularization for patients with diabetes mellitus and multivessel CAD are not clearly defined. Methods In the BARI 2D trial, the selected revascularization strategy, CABG or PCI, was based on physician discretion, declared independent of randomization to either immediate or deferred revascularization if clinically warranted. We analyzed factors favoring selection of CABG versus PCI in 1,593 diabetic patients with multivessel CAD enrolled between 2001 and 2005. Results Selection of CABG over PCI was declared in 44% of patients and was driven by angiographic factors including triple vessel disease (odds ratio [OR]: 4.43), left anterior descending stenosis >= 70% (OR: 2.86), proximal left anterior descending stenosis >= 50% (OR: 1.78), total occlusion (OR: 2.35), and multiple class C lesions (OR: 2.06) (all p < 0.005). Nonangiographic predictors of CABG included age >= 65 years (OR: 1.43, p = 0.011) and non-U.S. region (OR: 2.89, p = 0.017). Absence of prior PCI (OR: 0.45, p < 0.001) and the availability of drug-eluting stents conferred a lower probability of choosing CABG (OR: 0.60, p = 0.003). Conclusions The majority of diabetic patients with multivessel disease were selected for PCI rather than CABG. Preference for CABG over PCI was largely based on angiographic features related to the extent, location, and nature of CAD, as well as geographic, demographic, and clinical factors. (Bypass Angioplasty Revascularization Investigation in Type 2 Diabetes [BARI 2D]; NCT00006305) (J Am Coll Cardiol Intv 2009;2:384-92) (C) 2009 by the American College of Cardiology Foundation
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Homeopathy has been used for more than two hundred years to treat chronic disease using various approaches in a wide range of diseases. However, for acute disease and critical illness, application has been limited by inadequate training of homeopathic physicians and the small number of pertinent clinical studies. In view of the difficulty of practising homeopathy in Intensive Care Units (ICU), a protocol was developed to facilitate description of objective homeopathic symptoms with a ranking of symptoms appropriate for these situations (Protocol for Objective Homeopathic Semiology). Examples of favorable results with individualized homeopathic treatments for a series of cases of Systemic Inflammatory Response Syndrome (sepsis) are described. Homeopathy (2008) 97, 206-213.
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Object. The goal of this paper is to analyze the extension and relationships of glomus jugulare tumor with the temporal bone and the results of its surgical treatment aiming at preservation of the facial nerve. Based on the tumor extension and its relationships with the facial nerve, new criteria to be used in the selection of different surgical approaches are proposed. Methods. Between December 1997 and December 2007, 34 patients (22 female and 12 male) with glomus jugulare tumors were treated. Their mean age was 48 years. The mean follow-up was 52.5 months. Clinical findings included hearing loss in 88%, swallowing disturbance in 50%, and facial nerve palsy in 41%. Magnetic resonance imaging demonstrated a mass in the jugular foramen in all cases, a mass in the middle ear in 97%, a cervical mass in 85%, and an intradural mass in 41%. The tumor was supplied by the external carotid artery in all cases, the internal carotid artery in 44%, and the vertebral artery in 32%. Preoperative embolization was performed in 15 cases. The approach was tailored to each patient, and 4 types of approaches were designed. The infralabyrinthine retrofacial approach (Type A) was used in 32.5%; infralabyrinthine pre- and retrofacial approach without occlusion of the external acoustic meatus (Type B) in 20.5%; infralabyrinthine pre- and retrofacial approach with occlusion of the external acoustic meatus (Type C) in 41 W. and the infralabyrinthine approach with transposition of the facial nerve and removal of the middle ear structures (Type D) in 6% of the patients. Results. Radical removal was achieved in 91% of the cases and partial removal in 9%. Among 20 patients without preoperative facial nerve dysfunction, the nerve was kept in anatomical position in 19 (95%), and facial nerve function was normal during the immediate postoperative period in 17 (85%). Six patients (17.6%) had a new lower cranial nerve deficit, but recovery of swallowing function was adequate in all cases. Voice disturbance remained in all 6 cases. Cerebrospinal fluid leakage occurred in 6 patients (17.6%), with no need for reoperation in any of them. One patient died in the postoperative period due to pulmonary complications. The global recovery, based on the Karnofsky Performance Scale (KPS), was 100% in 15% of the patients, 90% in 45%, 80% in 33%, and 70% in 6%. Conclusions. Radical removal of glomus jugulare tumor can be achieved without anterior transposition of the facial nerve. The extension of dissection, however, should be tailored to each case based on tumor blood supply, preoperative symptoms, and tumor extension. The operative field provided by the retrofacial infralabyrinthine approach, or the pre- and retrofacial approaches. with or without Closure of the external acoustic meatus, allows a wide exposure of the jugular foramen area. Global functional recovery based on the KPS is acceptable in 94% of the patients. (DOI: 10.3171/2008.10.JNS08612)
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In this paper, we propose a method based on association rule-mining to enhance the diagnosis of medical images (mammograms). It combines low-level features automatically extracted from images and high-level knowledge from specialists to search for patterns. Our method analyzes medical images and automatically generates suggestions of diagnoses employing mining of association rules. The suggestions of diagnosis are used to accelerate the image analysis performed by specialists as well as to provide them an alternative to work on. The proposed method uses two new algorithms, PreSAGe and HiCARe. The PreSAGe algorithm combines, in a single step, feature selection and discretization, and reduces the mining complexity. Experiments performed on PreSAGe show that this algorithm is highly suitable to perform feature selection and discretization in medical images. HiCARe is a new associative classifier. The HiCARe algorithm has an important property that makes it unique: it assigns multiple keywords per image to suggest a diagnosis with high values of accuracy. Our method was applied to real datasets, and the results show high sensitivity (up to 95%) and accuracy (up to 92%), allowing us to claim that the use of association rules is a powerful means to assist in the diagnosing task.
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In vitro culture conditions affect both the maternal and embryonic expression of genes and is likely to alter both oocyte and embryo developmental competence. The search for better and less variable culture conditions simulating those in vivo has led to the development of defined culture media, with lower impact on the molecular reprogramming of oocytes and embryos. We evaluated embryo development and relative abundance (RA) of Hsp-70 and Bax transcripts in bovine blastocysts produced from oocytes matured in a chemically defined IVM system with synthetic polymers. Immature cumulus oocyte complexes (COCs) were matured for 22-24 h in alpha-MEM supplemented with IGF-1, insulin, 0.1% polyvinyl alcohol (PVA), or 0.1% polyvinylpyrrolidone (PVP), but without FSH or LH. The control group consisted of COCs matured it, TCM plus FSH and 10% estrous cow serum. After fertilization. presumptive zygotes were co-cultured with cumulus cells until 224 h post-insemination. Total RNA was isolated from embryo pools, reverse transcribed into cDNA, and subjected to transcript analysis by real-time PCR. Cleavage rate was higher (P < 0.05) for the control group (68.3%) than for the PVA (54.4%) and PVP-40 (58.3%) groups. Nevertheless. there was no difference among the PVA, PVP-40 and control groups in blastocyst or hatching rates. similarly, no difference in relative abundance of Hsp-70 and Bax transcripts was detected in comparison to the control group. We inferred that bovine oocytes can be matured in serum- and gonadotrophin-free medium supplemented with PVA or PVP, enriched with IGF-I and insulin, without altering post-cleavage development and relative abundance of some genes associated with stress and apoptosis. (C) 2009 Elsevier Inc. All rights reserved.
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Formal Concept Analysis is an unsupervised machine learning technique that has successfully been applied to document organisation by considering documents as objects and keywords as attributes. The basic algorithms of Formal Concept Analysis then allow an intelligent information retrieval system to cluster documents according to keyword views. This paper investigates the scalability of this idea. In particular we present the results of applying spatial data structures to large datasets in formal concept analysis. Our experiments are motivated by the application of the Formal Concept Analysis idea of a virtual filesystem [11,17,15]. In particular the libferris [1] Semantic File System. This paper presents customizations to an RD-Tree Generalized Index Search Tree based index structure to better support the application of Formal Concept Analysis to large data sources.
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Spontaneous blinking is essential for maintaining a healthy ocular surface and clarity of vision. The spontaneous blink rate (SBR) is believed to reflect a complex interaction between peripheral influences mediated by the eye surface and the central dopaminergic activity. The SBR is thus extremely variable and dependent on a variety of psychological and medical conditions. Many different methods have been employed to measure the SBR and the upper eyelid kinematics during a blink movement. Each has its own merits and drawbacks, and the choice of a specific method should be tailored to the specific needs of the investigation. Although the sequence of muscle events that leads to a blink has been fully described, knowledge about the neural control of spontaneous blinking activity is not complete. The tear film is dynamically modified between blinks, and abnormalities of the blink rate have an obvious influence on the ocular surface.