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- Segmentation of Blood Vessels and Optic Disc in Retinal Images. [JOURNAL ARTICLE]
- IEEE J Biomed Health Inform 2014 Jan 27.
Retinal image analysis is increasingly prominent as a non-intrusive diagnosis method in modern ophthalmology. In this paper, we present a novel method to segment blood vessels and optic disc in the fundus retinal images. The method could be used to support non-intrusive diagnosis in modern ophthalmology since the morphology of the blood vessel and the optic disc is an important indicator for diseases like diabetic retinopathy, glaucoma and hypertension. Our method takes as first step the extraction of the retina vascular tree using the graph cut technique. The blood vessel information is then used to estimate the location of the optic disc. The optic disc segmentation is performed using two alternative methods. The Markov Random Field (MRF) image reconstruction method segments the optic disc by removing vessels from the optic disc region and the Compensation Factor method segments the optic disc using prior local intensity knowledge of the vessels. The proposed method is tested on three public data sets, DIARETDB1, DRIVE and STARE. The results and comparison with alternative methods show that our method achieved exceptional performance in segmenting the blood vessel and optic disc.
- Multiple ecosystem services landscape index: A tool for multifunctional landscapes conservation. [JOURNAL ARTICLE]
- J Environ Manage 2014 Sep 26.:152-163.
The contribution of ecosystems to human well-being has been widely recognised. Taking into account existing trade-offs between ecosystem services (ES) at the farm scale and the dependence of multiple ES on processes that take place at the landscape scale, long-term preservation of multifunctional landscapes must be a priority. Studies carried out from such perspective, and those that develop appropriate indicators, could provide useful tools for integrating ES in landscape planning. In this study we propose a new integrative environmental indicator based on the ES provided by the landscape and named "multiple ecosystem services landscape index" (MESLI). Because synergies and trade-offs between ES are produced at regional or local levels, being different from those perceived at larger scales, MESLI was developed at municipality level. Furthermore, in order to identify main drivers of change in ES provision at the landscape scale an analysis of the relationship between the environmental and the socioeconomic characteristics of the municipalities was carried out. The study was located in the Basque Country and the results demonstrated that the MESLI index is a good tool to measure landscape multifunctionality at local scales. It is effective evaluating landscapes, distinguishing between municipalities based on ES provision, and identifying the drivers of change and their effects. This information about ES provisioning at the local level is usually lacking; therefore, MESLI would be very useful for policy-makers and land managers because it provides relevant information to local scale decision-making.
- Understanding Sexual Harassment Using Aggregate Construct Models. [JOURNAL ARTICLE]
- J Appl Psychol 2014 Sep 29.
Sexual harassment has received a substantial amount of empirical attention over the past few decades, and this research has consistently shown that experiencing these behaviors has a detrimental effect on employees' well-being, job attitudes, and behaviors at work. However, these findings, and the conclusions that are drawn from them, make the implicit assumption that the empirical models used to examine sexual harassment are properly specified. This article presents evidence that properly specified aggregate construct models are more consistent with theoretical structures and definitions of sexual harassment and can result in different conclusions about the nomological network of harassment. Results from 3 large samples, 2 military and 1 from a civilian population, are used to illustrate the differences between aggregate construct and reflective indicator models of sexual harassment. These analyses suggested that the factor structure and the nomological network of sexual harassment differ when modeling harassment as an aggregate construct. The implications of these results for the continued study of sexual harassment are discussed. (PsycINFO Database Record (c) 2014 APA, all rights reserved).
- Physiological Epidermal Growth Factor Concentrations Activate High Affinity Receptors to Elicit Calcium Oscillations. [JOURNAL ARTICLE]
- PLoS One 2014; 9(9):e106803.
Signaling mediated by the epidermal growth factor (EGF) is crucial in tissue development, homeostasis and tumorigenesis. EGF is mitogenic at picomolar concentrations and is known to bind its receptor on high affinity binding sites depending of the oligomerization state of the receptor (monomer or dimer). In spite of these observations, the cellular response induced by EGF has been mainly characterized for nanomolar concentrations of the growth factor, and a clear definition of the cellular response to circulating (picomolar) concentrations is still lacking. We investigated Ca2+ signaling, an early event in EGF responses, in response to picomolar doses in COS-7 cells where the monomer/dimer equilibrium is unaltered by the synthesis of exogenous EGFR. Using the fluo5F Ca2+ indicator, we found that picomolar concentrations of EGF induced in 50% of the cells a robust oscillatory Ca2+ signal quantitatively similar to the Ca2+ signal induced by nanomolar concentrations. However, responses to nanomolar and picomolar concentrations differed in their underlying mechanisms as the picomolar EGF response involved essentially plasma membrane Ca2+ channels that are not activated by internal Ca2+ store depletion, while the nanomolar EGF response involved internal Ca2+ release. Moreover, while the picomolar EGF response was modulated by charybdotoxin-sensitive K+ channels, the nanomolar response was insensitive to the blockade of these ion channels.
- Olanzapine-activated AMPK signaling in the dorsal vagal complex is attenuated by histamine H1 receptor agonist in female rats. [JOURNAL ARTICLE]
- Endocrinology 2014 Sep 29.:en20141326.
Weight gain and its related metabolic disorders are major side-effects associated with second generation antipsychotic drug (SGA) treatment. The dorsal vagal complex (DVC) and AMP-activated protein kinase (AMPK) are implicated in the regulation of food intake and body weight. Blocking the histamine H1 receptor (H1R) contributes to antipsychotic-induced weight gain. The present study investigated the time-dependent effect of olanzapine treatment (8, 16 and 36 days) on DVC AMPK signaling in olanzapine-induced weight gain, and whether these changes are associated with olanzapine-induced H1 receptor antagonism. During the 8-day olanzapine treatment the rats were hyperphagic and rapidly gained weight. The phosphorylation of AMPK (pAMPK: activated AMPK) as well as its directly downstream phospho-Acetyl-CoA carboxylase (pACC) was significantly increased. The pAMPK/AMPK ratio, an indicator of AMPK activity, was significantly positively correlated with feeding efficiency and weight gain. As treatment was prolonged (16 and 36-day olanzapine treatment), the rats were no longer hyperphagic, and there were no longer any changes in DVC AMPK signaling. Although the DVC H1R protein expression was not significantly altered by olanzapine, the pAMPK expression was significantly positively correlated with the H1R level after the 8, 16, and 36-day olanzapine treatments. Moreover, we showed that an H1R agonist, 2-(3-trifluoromethylphenyl) histamine, significantly inhibited the olanzapine-induced hyperphagia and DVC AMPK activation in a dose-dependent manner. These results suggest a time-dependent role of DVC AMPK in olanzapine-induced obesity. Thus, olanzapine-induced DVC AMPK activation may be at least partially related to olanzapine's antagonistic effect on the H1R.
- Hemodynamic Response to Sildenafil in Patients with Decompensated Congestive Heart Failure Can Be Predicted by Deceleration Time of Transmitral Flow. [JOURNAL ARTICLE]
- J Cardiovasc Pharmacol 2014 Sep 26.
It remains unknown how sildenafil acutely provides hemodynamic alterations in patients with decompensated congestive heart failure. The aim of this study was to investigate whether myocardial and/or hemodynamic conditions affect hemodynamic response to sildenafil in patients with decompensated heart failure.Twenty five consecutive patients with decompensated congestive heart failure were enrolled. The patients underwent echocardiography before and an hour after a single oral administration of sildenafil (20 mg). Sildenafil decreased pulmonary vascular resistance by 24% (p<0.05), and increased left ventricular (LV) time-velocity integral by 17% (p<0.05). Alteration of the ratio of peak velocity of early LV filling to early diastolic myocardial velocity (E/E'), an indicator of LV filling pressure, following administration of sildenafil, negatively associated with the deceleration time of early filling wave (DcT) at baseline. The patients with baseline DcT ≥ 200 msec. (n = 11) exhibited E/E' increase, whereas the patients with baseline DcT < 200 msec. (n = 14) exhibited E/E' decrease.Administration of sildenafil elevated LV filling pressure in decompensated heart failure patients with shortened deceleration time of early diastolic transmitral flow.
- Ionic Liquid-Based Fluorescein Colorimetric pH Nanosensors. [JOURNAL ARTICLE]
- RSC Adv 2013 Nov 21; 3(43):21054-21061.
A novel pH sensitive, colorimetric ionic liquid nanosensor based on phosphonium salts of fluorescein is reported. Herein, fluorescein salts of various stoichiometries were synthesized by use of a trihexyltetradecylphosphonium cation [TTP](+) in combination with dianionic [FL](2-) and monoanionic [FL](-) fluorescein. Nanomaterials derived from these two compounds yielded contrasting colorimetric responses in neutral and acidic environments. Variations in fluorescence spectra as a function of pH were also observed. Examination of TEM and DLS data revealed significant expansion in the diameter of [TTP]2[FL] nanodroplets in acidic environments of variable pHs. A similar trend was also observed for [TTP][FL] nanoparticles. The pH dependent colorimetric and other optical properties of these nanomaterials are attributed to alterations in molecular orientations and stacking as suggested by measuring the absorption, fluorescence, and zeta potential. Since the pH is an important indicator for many diseases, including cancer, these nanosensors are considered to be potential candidates for biomedical applications.
- Metabolic syndrome as an indicator of high cardiovascular risk in patients with diabetes: Analyses based on Korea National Health and Nutrition Examination Survey (KNHANES) 2008. [Journal Article]
- Diabetol Metab Syndr 2014; 6(1):98.
Patients with either diabetes mellitus (DM) or metabolic syndrome (MS) are recognized as a high risk group for cardiovascular disease (CVD). Several studies have demonstrated the clinical value of MS for predicting additional CVD risk in the DM population, although the clinical significance remains debatable.We used the Korea National Health and Nutrition Examination Survey (KNHANES) 2008, which is the national representative database. We classified the KNHANES subjects based on MS and glucose tolerance status, and compared clinical characteristics and future CVD risk among the subgroups.A total of 796 of the 4314 subjects were diagnosed with MS. Their clinical characteristics were significantly different from patients without MS. Prevalence of DM was 9.5% in subjects with MS, but only 1.1% in subjects without MS. In addition, there was no MS in 30.9% of total DM patients who were enrolled in this study. For the normal and impaired fasting glucose subgroups, the prevalence of moderate (5-10%) and high (>10%) CVD risk was significantly higher in patients with MS than in patients without MS (p < 0.001). However, in the DM subgroup, even after multiple adjustments, there were no differences in clinical characteristics or in the prevalence of moderate to high CVD risk according to MS status. That said, LDL cholesterol in the DM group without MS was significantly higher than in the DM group with MS (p = 0.010).The efficacy of MS as a screening tool for high CVD risk may be limited in DM patients, and conventional risk factors such as LDL may be more important.
- Prognostic importance of neutrophil-lymphocyte ratio in critically ill patients: short- and long-term outcomes. [JOURNAL ARTICLE]
- Am J Emerg Med 2014 Sep 6.
The number of critically ill patients admitted to the emergency department increases daily. To decrease mortality, interventions and treatments should be conducted in a timely manner. It has been found that the neutrophil-lymphocyte ratio (NLR) is related to mortality in some disease groups, such as acute coronary syndrome and pulmonary emboli. The effect of the NLR on mortality is unknown in critically ill patients who are admitted to the emergency department. Our aim in this study is to evaluate the effect of the NLR on mortality in critically ill patients.This study was planned as a prospective, observational cohort study. Patients who were admitted to the emergency department because they were critically ill and required the intensive care unit were included in the study. Demographic characteristics, Acute Physiology and Chronic Health Evaluation II (APACHE II), Sepsis-related Organ Failure Assessment, Glasgow Coma Score, and NLR values were recorded upon emergency department admission. The patients were followed up for sepsis, ventilator-associated pneumonia, multiorgan failure, in-hospital mortality, and 6-month mortality.The median (interquartile range) age of the 373 patients was 74 (190) years, and 54.4% were men. Neutrophil-lymphocyte ratio values were divided into quartiles, as follows: less than 3.48, 3.48 to 6.73, 6.74-13.6, and more than 13.6. There was no difference among these 4 groups regarding demographic characteristics, APACHE II score, Sepsis-related Organ Failure Assessment score, Glasgow Coma Score, and length of hospital stay (P > .05). In the multivariable Cox regression model, in-hospital mortality and 6-month mortality NLR were hazard ratio (HR), 1.63 (1.110-2.415; P = .01) and HR, 1.58 (1.136-2.213; P = .007), respectively, and APACHE II scores were detected as independent indicators.The NLR is a simple, cheap, rapidly available, and independent indicator of short- and long-term mortalities. We suggest that the NLR can provide direction to emergency department physicians for interventions, particularly within a few hours after admission, in the critically ill patient group.
- En face swept-source optical coherence tomography detecting thinning of inner retinal layers as an indicator of capillary nonperfusion. [JOURNAL ARTICLE]
- Eur J Ophthalmol 2014 Sep 12.:0.
To report en face swept-source optical coherence tomography (SS-OCT) as a noninvasive detection modality for regions of retinal layer thinning that are potential indicators of retinal nonperfusion areas (NPAs) in patients with branch retinal vein occlusion (BRVO).Thirty-one eyes of 46 patients with BRVO showing a definite retinal NPA larger than 1 disc in diameter within the vascular arcades were included in this study. We calculated the overlapping correspondence ratio between presumed NPA, which appeared as a dark area in en face SS-OCT, and definite NPA in corresponding fluorescein angiography (FA) images. The correlation between brightness in en face SS-OCT images and corresponding ganglion cell complex (GCC) thickness determined by SD-OCT GCC maps was evaluated as well.Measured NPA size in FA and presumed NPA size in en face SS-OCT showed strong correlation (r = 0.746, p<0.001) and colocalization. Reliable agreement between the 2 methods was confirmed by size comparisons (p = 0.11), with an overlapping correspondence ratio of 0.73.The results suggest that en face SS-OCT is a noninvasive and relatively reliable method for delineating retinal thinning as an indicator of NPAs in eyes with BRVO. Because SS-OCT can be performed without mydriasis, this procedure may be an option for evaluating NPAs on a screening basis and during follow-up to reduce the number of FA examinations that carry very rare, but potentially fatal, allergic side effects.