33 resultados para Inverse problems for PDE, electrical impedance tomography, factorization method


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AIMS The purpose of the present study was to investigate the relationship between in-stent neoatherosclerosis (NA) and native atherosclerosis progression of untreated coronary segments. METHODS AND RESULTS In-stent NA was assessed by optical coherence tomography (OCT) among patients included in the SIRTAX-LATE OCT study 5 years after drug-eluting stent (DES) (sirolimus-eluting and paclitaxel-eluting stents) implantation. Neoatherosclerosis was defined as the presence of fibroatheroma or fibrocalcific plaque within the neointima of stented segments with a longitudinal extension >1.0 mm. Atherosclerosis progression in untreated native coronary segments was evaluated by serial quantitative coronary angiography (QCA). The change in minimal lumen diameter (MLD) was serially assessed within matched segments at baseline and 5-year angiographic follow-up. The key clinical endpoint was non-target lesion (non-TL) revascularization throughout 5 years. A total of 88 patients with 88 lesions were available for OCT analysis 5 years after DES implantation. In-stent NA was observed in 16% of lesions with the majority of plaques being fibroatheromas (11.4%) followed by fibrocalcific plaques (5.7%). A total of 704 non-TL segments were serially evaluated by QCA. Between baseline and 5-year follow-up, the reduction in MLD was significantly more pronounced in patients with NA (-0.25 mm, 95% CI -0.36 to -0.17 mm) when compared with patients without NA (-0.13 mm, 95% CI -0.17 to -0.10 mm, P = 0.002). Similarly, non-TL revascularization was more frequent in patients with NA (78.6%) when compared with patients without NA (44.6%, P = 0.028) throughout 5 years. CONCLUSIONS In-stent NA is more common among patients with angiographic and clinical evidence of native atherosclerosis progression suggesting similar pathophysiological mechanisms.SIRTAX trial is registered at http://www.clinicaltrials.gov/ct2/show/NCT00617084.

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In the present review, we deliver an overview of the involvement of metabotropic glutamate receptor 5 (mGluR5) activity and density in pathological anxiety, mood disorders and addiction. Specifically, we will describe mGluR5 studies in humans that employed Positron Emission Tomography (PET) and combined the findings with preclinical animal research. This combined view of different methodological approaches-from basic neurobiological approaches to human studies-might give a more comprehensive and clinically relevant view of mGluR5 function in mental health than the view on preclinical data alone. We will also review the current research data on mGluR5 along the Research Domain Criteria (RDoC). Firstly, we found evidence of abnormal glutamate activity related to the positive and negative valence systems, which would suggest that antagonistic mGluR5 intervention has prominent anti-addictive, anti-depressive and anxiolytic effects. Secondly, there is evidence that mGluR5 plays an important role in systems for social functioning and the response to social stress. Finally, mGluR5's important role in sleep homeostasis suggests that this glutamate receptor may play an important role in RDoC's arousal and modulatory systems domain. Glutamate was previously mostly investigated in non-human studies, however initial human clinical PET research now also supports the hypothesis that, by mediating brain excitability, neuroplasticity and social cognition, abnormal metabotropic glutamate activity might predispose individuals to a broad range of psychiatric problems.

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BACKGROUND Oesophageal clearance has been scarcely studied. AIMS Oesophageal clearance in endoscopy-negative heartburn was assessed to detect differences in bolus clearance time among patients sub-grouped according to impedance-pH findings. METHODS In 118 consecutive endoscopy-negative heartburn patients impedance-pH monitoring was performed off-therapy. Acid exposure time, number of refluxes, baseline impedance, post-reflux swallow-induced peristaltic wave index and both automated and manual bolus clearance time were calculated. Patients were sub-grouped into pH/impedance positive (abnormal acid exposure and/or number of refluxes) and pH/impedance negative (normal acid exposure and number of refluxes), the former further subdivided on the basis of abnormal/normal acid exposure time (pH+/-) and abnormal/normal number of refluxes (impedance+/-). RESULTS Poor correlation (r=0.35) between automated and manual bolus clearance time was found. Manual bolus clearance time progressively decreased from pH+/impedance+ (42.6s), pH+/impedance- (27.1s), pH-/impedance+ (17.8s) to pH-/impedance- (10.8s). There was an inverse correlation between manual bolus clearance time and both baseline impedance and post-reflux swallow-induced peristaltic wave index, and a direct correlation between manual bolus clearance and acid exposure time. A manual bolus clearance time value of 14.8s had an accuracy of 93% to differentiate pH/impedance positive from pH/impedance negative patients. CONCLUSIONS When manually measured, bolus clearance time reflects reflux severity, confirming the pathophysiological relevance of oesophageal clearance in reflux disease.