86,892 research outputs found
Shortened head-up tilting test guided by systolic pressure reductions in neurocardiogenic syncope
No full textBACKGROUND: Asymptomatic reductions in arterial pressure have been reported to occur before the onset of tilt-induced syncope. We investigated the predictive value of these reductions for a positive tilt result.
METHODS AND RESULTS: In a first study, 238 consecutive healthy subjects with unexplained syncope underwent a passive tilt table test. Finger systolic arterial pressure (SAP) recordings made it possible to calculate how many of the beat-to-beat SAP values during the first 15 minutes of tilt were lower than the lowest value recorded at baseline. Neurocardiogenic syncope was diagnosed in 73 subjects; 28 fainted after 15 minutes of tilt and experienced more pressure reductions than did the subjects with a negative test (328+/-400 versus 119+/-284; P<0.01). More than 14 SAP reductions during the first 15 minutes of tilt allowed us to predict a positive test with 93% sensitivity, 58% specificity, and positive and negative predictive values of 28% and 98%, respectively. In a second prospective study (80 consecutive subjects), the online analysis of this criterion by visually inspecting a Finapres monitor showed 80% sensitivity, 85% specificity, and positive and negative predictive values of 57% and 94%.
CONCLUSIONS: In healthy subjects with unexplained syncope, the evaluation of SAP reductions during the first 15 minutes of tilt is a marker of systolic pressure instability preceding syncope and constitutes a simple and good predictor of tilt outcome that could be used to guide test duration
Present concepts in management of atrial fibrillation: From drug therapy to ablation
No full textAtrial fibrillation (AF) management requires knowledge of its pattern of presentation, underlying conditions, and decisions about restoration and maintenance of sinus rhythm, control of the ventricular rate, and anti-thrombotic therapy. Maintenance of sinus rhythm is a desirable goal in AF patients because the prevention of recurrence may improve cardiac function, relieve symptoms and reduce the likelihood of adverse events. Anti-arrhythmic drug therapy is the first-line treatment for patients with paroxysmal and persistent AF based on current guidelines. However, currently used drugs have limited efficacy and cause cardiac and extracardiac toxicity. Thus, there is a continued need to develop new drugs, device and ablative approaches to rhythm management. Additionally, simpler and safer stroke prevention regimens are needed for AF patients on life-long anticoagulation, including occlusion of the left atrial appendage. The results of the Randomized Evaluation of Long-Term Anticoagulant Therapy study are encouraging in these settings. Knowledge on the pathophysiology of AF is rapidly expanding and identification of focally localized triggers has led to the development of new treatment options for this arrhythmia. Conversely, the clinical decision whether to restore and maintain sinus rhythm or simply control the ventricular rate has remained a matter of intense debate. In the minority of patients in whom AF cannot be adequately managed by pharmacological therapy, the most appropriate type of non-pharmacological therapy must be selected on an individualized basis. Curative treatment of AF with catheter ablation is now a legitimate option for a large number of patients. The evolution of hybrid therapy, in which two or more different strategies are employed in the same patient, may be an effective approach to management of AF. In any case, planning a treatment regimen for AF should include evaluation of the risks inherent in the use of various drugs as well as more invasive strategies
Uno standard di accessibilità relazionale delle organizzazioni. Spunti di riflessione dalla fruizione del patrimonio naturale
No full textObiettivi. Obiettivo del lavoro è proporre una norma volontaria finalizzata a migliorare l’accessibilità relazionale delle organizzazioni e i rapporti con l’utenza esterna. L’aggettivazione posta al termine di accessibilità prende le distanze da concetti fisici o virtuali, richiamando l’attenzione sulla relazionalità.
Metodologia. Inquadrato il concetto di accessibilità relazionale, si definiscono l’approccio e lo schema logico della norma attingendo ad approcci teorici manageriali e multidisciplinari. Da un punto di vista empirico, spunti utili sono stati tratti dall’ambito ambientale secondo una duplice prospettiva: dalle esperienze in tema, quindi da una prospettiva d’offerta; dal punto di vista degli utenti, per cogliere la prospettiva della domanda. Mettendo a sistema i contributi teorici e le risultanze empiriche, si definiscono lo schema logico ed alcune linee guida utili a migliorare l’accessibilità relazionale di differenti contesti organizzativi e settoriali.
Risultati. La norma, nel perseguire il fine dell’accessibilità relazionale, può consentire alle organizzazioni di accrescere il loro valore sociale ed economico - in termini di vantaggi competitivi, immagine, rapporti con i soggetti esterni.
Limiti della ricerca. Lo schema proposto presenta limiti connessi all’applicazione della norma che, definita a partire da una specifica realtà di utenza (minori) e di organizzazione (un parco naturale), è in corso di sperimentazione in altri contesti organizzativi al fine di verificarne la fungibilità.
Implicazioni pratiche. La sua applicazione nelle diverse organizzazioni collegate alla gestione del patrimonio culturale potrebbe intensificare l’adozione di approcci manageriali.
Originalità del lavoro. Il lavoro è originale nella metodologia e nello strumento, non essendovi a conoscenza degli Autori proposte simili.Objectives. This work aims to propose a standard on relationship accessibility of organizations, oriented to reduce drawbacks and improve the relationship with external users. The term used is not meant as physical or virtual accessibility; on the contrary, it refers to relationship accessibility.
Methodology. After having defined a relationship concept, the approach and logical frame of standard are defined based on managerial literature. Useful ideas have come out from the environmental field according to a double perspective: from the experience realized on the topic, therefore from a supply perspective; from the users point of view, to catch a demand perspective. Putting together theoretical insights and empirical results, the logical frame and some useful guidelines to improve the accessibility of different organizational contexts are defined.
Findings. The standard, to pursue the aim of relationship accessibility, could allow the organizations to increase the social and economic value - e.g. in terms of competitive advantages, image, and relationships with the different external users-.
Research limits. The scheme proposed shows limits related to the application of the standard that, defined from a specific target of users (minors) and organization (a natural park), is being tested in other organizational contexts in order to verify its fungibility.
Pratical implications. Its application in the organizational contexts connected to the cultural heritage world could intensify the adoption of managerial approaches.
Originality of the study. The work is original in its methodology and tool, since the Authors have no knowledge of standard on the issue
Clinical significance of type 2 iodothyronine deiodinase polymorphism
No full textIntroduction: Biological activity of thyroid hormones (TH) is regulated by enzymes known as deiodinases. The most important is represented by the type 2 deiodinase (D2), which is the main T4-activating enzyme, ubiquitous in human tissues and therefore essential in many metabolic processes. A single nucleotide polymorphism (SPN) of D2, known as Thr92Ala (rs225014), has been reported in the general population while other polymorphisms are less frequently described. Areas covered: Several authors investigated the potential metabolic effect of these polymorphisms in the general population and in specific groups of patients. Thr92Ala polymorphism was mainly studied in patients with autoimmune or surgical hypothyroidism and in patients with physical/psychological disorders that could be related to an overt hypothyroidism. Susceptibility to develop more severe type 2 diabetes or insulin resistance has also been evaluated. Commentary: There is an increasing evidence that the presence of D2 polymorphisms may play a pivotal role in a better definition and customized therapeutic approach of patients with hypothyroidism and/or type 2 diabetes, suggesting that these patients should be screened for D2 polymorphisms. Nevertheless, further research should be performed in order to clarify the association between D2 polymorphisms, metabolic alterations and clinical conditions of the carrier patients
Rapid discrimination of Italian Prosecco wines by head-space gas-chromatography basing on the volatile profile as a chemometric fingerprint
No full textProsecco wine is one of the most important products of the Italian oenological landscape. Its production is strictly regulated by several disciplinary. Thus, it is important to verify the quality of the final product, to defend the uniqueness of this wine. This work describes a rapid method to discriminate among varieties of Italian Prosecco wine using the volatile-fraction distribution as an untargeted fingerprint. The volatile profile corresponds to gas-chromatograms obtained in head-space mode. Principal components analysis of chromatograms allows discriminating the Prosecco samples depending on geographical origin, cultivation practices, and wine-making technologies. In particular, conventional vs. biological agriculture and manual vs. mechanical harvesting give well-separated clusters when projected on a scores plot. Influence plots allow evaluating which variables are the most effective to describe the differences between oenological classes, which are declared in the label and coded in the disciplinary of origin denomination. The identification of discriminating molecules in the volatile profile is also performed by Kovats indexes. Thus, possible chemical markers for the classification of Italian Prosecco wines are appointed
Head-up tilt testing for diagnosing vasovagal syncope: a meta-analysis.
No full textBACKGROUND: A systematic evaluation focused on sensitivity and specificity of head-up tilt testing (HUT) for diagnosing vasovagal syncope has not been previously performed. We conducted a meta-analysis of studies comparing HUT outcome between patients with syncope of unknown origin and control subjects without previous syncope.
METHODS: We searched Pubmed and Embase databases for all English-only articles concerning case-control studies estimating the diagnostic yield of HUT, and selected 55 articles, published before March 2012, including 4361 patients and 1791 controls. The influence of age, test duration, tilt angle, and nitroglycerine or isoproterenol stimulation on tilt testing outcome was analyzed.
RESULTS: Head-up tilt testing demonstrated to have a good overall ability to discriminate between symptomatic patients and asymptomatic controls with an area under the summary receiver-operating characteristics curve of 0.84 and an adjusted diagnostic odds ratio of 12.15 (p<0.001). A significant inverse relationship between sensitivity and specificity of tilt testing for each study was observed (p<0.001). At multivariate analysis, advancing age and a 60° tilt angle showed a significant effect in reducing sensitivity and increasing specificity of the test. Nitroglycerine significantly raised tilt testing sensitivity by maintaining a similar specificity in comparison to isoproterenol.
CONCLUSIONS: The results from this meta-analysis show the high overall performance of HUT for diagnosing vasovagal syncope. Our findings provide useful information for evaluating clinical and instrumental parameters together with pharmacological stressors influencing HUT accuracy. This could allow the drawing of tilt testing protocols tailored on the diagnostic needs of each patient with unexplained syncope
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