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Journal of Thrombosis and Thrombolysis - Ventilation/perfusion (V/Q) imaging and computed tomography pulmonary angiography (CTPA) are common tools for acute pulmonary embolism (PE) diagnosis....  相似文献   
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Brain tissue segmentation in magnetic resonance imaging volumes is an important image processing step for analyzing the human brain. This paper presents a novel approach named Pseudo-Label Assisted Self-Organizing Map (PLA-SOM) that enhances the result produced by a base segmentation method. Using the output of a base method, PLA-SOM calculates pseudo-labels in order to keep inter-class separation and intra-class compactness in the training phase. For the mapping phase, PLA-SOM uses a novel fuzzy function that combines feature space learned by the SOM’s prototypes, topological ordering from the map, and spatial information from a brain atlas. We assessed PLA-SOM performance on synthetic and real MRIs of the brain, obtained from the BrainWeb and the Internet Brain Image Repository datasets. The experimental results showed evidence of segmentation improvement achieved by the proposed method over six different base methods. The best segmentation improvements reported by PLA-SOM on synthetic brain scans are 11%, 6%, and 4% for the tissue classes cerebrospinal fluid, gray matter, and white matter, respectively. On real brain scans, PLA-SOM achieved segmentation enhancements of 15%, 5%, and 12% for cerebrospinal fluid, gray matter, and white matter, respectively.

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Introduction

Cigarette smoking is a major risk factor in the development of chronic obstructive pulmonary disease (COPD). Serotonin levels have been associated with COPD and smoking has been as a significant modulator. Elevated levels of serotonin are responsible for bronchoconstriction and pulmonary vasoconstriction and also nicotine dependence, thus serotonin response could be affected by genetic polymorphisms in transporters and receptors of serotonin.

Objectives

The aim of the current study was to analyze the effect of SLC6A4 (5HTT_LPR) (rs25531) and HTR2A-1438G/A (rs6311) genetic polymorphisms on the relation between smoking habits and COPD.

Methods

The association between SLC6A4 (5HTT_LPR) (rs25531), HTR2A-1438G/A (rs6311), smoking degree and COPD was analyzed in a total of 77 COPD patients (active smokers) and 90 control subjects (active healthy smokers). The DNA was extracted of peripheral leukocytes samples and genotyping was performed using an allele specific polymerase chain reaction.

Results

The distribution of SLC6A4 genotypes did not vary between healthy smokers and COPD patients (P = 0.758). On the other hand, the A allele of HTR2A (rs6311) was significantly associated with COPD incidence in the trend model (P = 0.02; 1.80 [1.04–3.11]). Among all smokers, this allele was also associated with the number of pack years smoked (P = 0.02) and also, we observed a marginal association with FEV1/FVC values (P = 0.06).

Conclusion

Our results point a possible role of the A allele of HTR2A (rs6311) in COPD pathogenesis, suggesting that this effect depends partly on tobacco consumption due to a gene-by-environment interaction.  相似文献   
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Introduction and objectivesNeoatherosclerosis is one of the causes of in-stent restenosis (ISR). Our objective was to evaluate the influence of neoatherosclerosis on prognosis and treatment response in patients with ISR.MethodsThis is a pooled analysis of the optical coherence tomography (OCT)-substudies of 2 multicenter, randomized clinical trials, RIBS IV and V, comparing treatment with paclitaxel-coated balloon vs everolimus-eluting stent in patients with ISR. OCT evaluation was performed at baseline and at 6 to 9 months. Neoatherosclerosis was defined in baseline OCT as neointima with calcified or lipid content. We evaluated the angiographic and OCT results at 6 to 9 months and the occurrence of major adverse cardiovascular events at 3 years of follow-up in patients with and without neoatherosclerosis treated with paclitaxel-coated balloon or everolimus-eluting stents.ResultsSixty-four patients underwent OCT at the time of the index procedure. Neoatherosclerosis was documented in 23 (36%) lesions. Angiographic follow-up at 6 to 9 months showed no differences in restenosis [5 (24%) vs 6 (15%) P = .49], minimum lumen diameter (1.79 ± 0.7 vs 1.94 ± 0.6 mm; P = .41) or late loss (0.33 ± 0.7 vs 0.15 ± 0.5; P = .34) in patients with and without neoatherosclerosis, respectively. Follow-up OCT confirmed the absence of differences in quantitative parameters and the characteristics of tissue coverage between the 2 groups. At 3 years of follow-up, the major adverse cardiovascular events rate was 3 (13%) vs 5 (12%) in the neoatherosclerosis and nonneoatherosclerosis groups (HR, 0.94; 95%CI, 0.22-3.93; P = .93).ConclusionsIn this limited study population, OCT-defined neoatherosclerosis did not seem to influence acute and long-term outcomes in patients randomized to paclitaxel-coated balloon or everolimus-eluting stents for ISR.  相似文献   
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