346 research outputs found

    Connectivity for the frisbee architecture

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    In this paper we investigate the kconnectivity threshold of distributed dense ad hoc heterogeneous wireless sensor network architecture. We consider the situation when sensors are deployed in the surveillance area according to a uniform distribution perturbed by a Gaussian noise. We derive analytically the minimum detection range which guarantees an emerging structure in the network, namely the connectivity, which becomes larger and larger as the number of sensors in the network increase. This allows the target track to be propagated almost surely throughout the network using the minimum possible amount ofprime energy. We report the results of some simulation experiments which further support the theoretical results

    Algorithms for the selection of the active sensors in distributed tracking: Comparison between Frisbee and GNS methods

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    This paper compares two different approaches for sensor selection for distributed tracking: 1) The Frisbee method, and 2) Global Node Selection (GNS). The Frisbee method is based on the proximity of the nodes to the predicted location of the target; GNS is based on minimizing the unbiased Cramer Rao lower bound (CRLB). Both theoretical and experimental results indicate that the Frisbee method is as effective as GNS. Furthermore, the Frisbee method is attractive due to its very light computational load

    Serotonin Antagonism Improves Platelet Inhibition in Clopidogrel Low-Responders after Coronary Stent Placement: An In Vitro Pilot Study

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    Increased residual platelet reactivity remains a burden for coronary artery disease (CAD) patients who received a coronary stent and do not respond sufficiently to treatment with acetylsalicylic acid and clopidogrel. We hypothesized that serotonin antagonism reduces high on-treatment platelet reactivity. Whole blood impedance aggregometry was performed with arachidonic acid (AA, 0.5 mM) and adenosine diphosphate (ADP, 6.5 ”M) in addition to different concentrations of serotonin (1–100 ”M) in whole blood from 42 CAD patients after coronary stent placement and 10 healthy subjects. Serotonin increased aggregation dose-dependently in CAD patients who responded to clopidogrel treatment: After activation with ADP, aggregation increased from 33.7±1.3% to 40.9±2.0% in the presence of 50 ”M serotonin (p<0.05) and to 48.2±2.0% with 100 ”M serotonin (p<0.001). The platelet serotonin receptor antagonist ketanserin decreased ADP-induced aggregation significantly in clopidogrel low-responders (from 59.9±3.1% to 37.4±3.5, p<0.01), but not in clopidogrel responders. These results were confirmed with light transmission aggregometry in platelet-rich plasma in a subset of patients. Serotonin hence increased residual platelet reactivity in patients who respond to clopidogrel after coronary stent placement. In clopidogrel low-responders, serotonin receptor antagonism improved platelet inhibition, almost reaching responder levels. This may justify further investigation of triple antiplatelet therapy with anti-serotonergic agents

    Sodium/glucose cotransporter 2 (SGLT2) inhibitors improve cardiac function by reducing JunD expression in human diabetic hearts

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    Background: The pathogenesis of experimental diabetic cardiomyopathy may involve the activator protein 1 (AP-1) member, JunD. Using non-diabetic heart transplant (HTX) in recipients with diabetes, we examined the effects of the diabetic milieu (hyperglycemia and insulin resistance) on cardiac JunD expression over 12 months. Because sodium/glucose cotransporter-2 inhibitors (SGLT2i) significantly reverse high glucose-induced AP-1 binding in the proximal tubular cell, we investigated JunD expression in a subgroup of type 2 diabetic recipients receiving SGLT2i treatment. Methods: We evaluated 77 first HTX recipients (40 and 37 patients with and without diabetes, respectively). Among the recipients with diabetes, 17 (45.9%) were receiving SGLT2i treatment. HTX recipients underwent standard clinical evaluation (metabolic status, echocardiography, coronary computed tomography angiography, and endomyocardial biopsy). In the biopsy samples, we evaluated JunD, insulin receptor substrates 1 and 2 (IRS1 and IRS2), peroxisome proliferator-activated receptor-γ (PPAR-γ), and ceramide levels using real-time polymerase chain reaction and immunofluorescence. The biopsy evaluations in this study were performed at 1–4 weeks (basal), 5–12 weeks (intermediate), and up to 48 weeks (final, end of 12-month follow-up) after HTX. Results: There was a significant early and progressive increase in the cardiac expression of JunD/PPAR-γ and ceramide levels, along with a significant decrease in IRS1 and IRS2 in recipients with diabetes but not in those without diabetes. These molecular changes were blunted in patients with diabetes receiving SGLT2i treatment. Conclusion: Early pathogenesis in human diabetic cardiomyopathy is associated with JunD/PPAR-γ overexpression and lipid accumulation following HTX in recipients with diabetes. Remarkably, this phenomenon was reduced by concomitant therapy with SGLT2i, which acted directly on diabetic hearts

    Lipid Accumulation in Hearts Transplanted From Nondiabetic Donors to Diabetic Recipients

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    Background: Early pathogenesis of diabetic cardiomyopathy (DMCM) may involve lipotoxicity of cardiomyocytes in the context of hyperglycemia. There are many preclinical studies of DMCM pathogenesis, but the human evidence is still poorly understood. Objectives: By using a nondiabetic mellitus (non-DM) heart transplanted (HTX) in diabetes mellitus (DM) recipients, this study conducted a serial study of human heart transplant recipients evaluating cardiac effects of diabetic milieu (hyperglycemia and insulin resistance) on lipotoxic-mediated injury. We evaluated cardiomyocyte morpho-pathology by seriated biopsies of healthy implanted hearts in DM recipients during 12-month follow-up from HTX. Because metformin reduces ectopic lipid accumulation, we evaluated the effects of the drug in a nonrandomized subgroup. Methods: The DMCM-AHEAD (Diabetes and Lipid Accumulation and Heart Transplant) prospective ongoing study (NCT03546062) evaluated 158 first HTX recipients (82 non-DM, 76 DM of whom 35 [46%] were receiving metformin). HTX recipients were undergoing clinical standard evaluation (metabolic status, echocardiography, coronary computed tomography angiography, and endomyocardial biopsies). Biopsies evaluated immune response, Oil Red-O staining, ceramide, and triacylglycerol levels. Lipotoxic factors and insulin resistance were evaluated by reverse transcriptase–polymerase chain reaction. Results: There was a significant early and progressive cardiomyocyte lipid accumulation in DM but not in non-DM recipients (p = 0.019). In the subgroup receiving metformin, independently from immunosuppressive therapy that was similar among groups, lipid accumulation was reduced in comparison with DM recipients not receiving the drug (hazard ratio: 6.597; 95% confidence interval: 2.516 to 17.296; p &lt; 0.001). Accordingly, lipotoxic factors were increased in DM versus non-DM recipients, and, relevantly, metformin use was associated with fewer lipotoxic factors. Conclusions: Early pathogenesis of human DMCM started with cardiomyocyte lipid accumulation following HTX in DM recipients. Metformin use was associated with reduced lipid accumulation independently of immunosuppressive therapy. This may constitute a novel target for therapy of DMCM

    Lipid Accumulation in Hearts Transplanted From Nondiabetic Donors to Diabetic Recipients

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    Background: Early pathogenesis of diabetic cardiomyopathy (DMCM) may involve lipotoxicity of cardiomyocytes in the context of hyperglycemia. There are many preclinical studies of DMCM pathogenesis, but the human evidence is still poorly understood. Objectives: By using a nondiabetic mellitus (non-DM) heart transplanted (HTX) in diabetes mellitus (DM) recipients, this study conducted a serial study of human heart transplant recipients evaluating cardiac effects of diabetic milieu (hyperglycemia and insulin resistance) on lipotoxic-mediated injury. We evaluated cardiomyocyte morpho-pathology by seriated biopsies of healthy implanted hearts in DM recipients during 12-month follow-up from HTX. Because metformin reduces ectopic lipid accumulation, we evaluated the effects of the drug in a nonrandomized subgroup. Methods: The DMCM-AHEAD (Diabetes and Lipid Accumulation and Heart Transplant) prospective ongoing study (NCT03546062) evaluated 158 first HTX recipients (82 non-DM, 76 DM of whom 35 [46%] were receiving metformin). HTX recipients were undergoing clinical standard evaluation (metabolic status, echocardiography, coronary computed tomography angiography, and endomyocardial biopsies). Biopsies evaluated immune response, Oil Red-O staining, ceramide, and triacylglycerol levels. Lipotoxic factors and insulin resistance were evaluated by reverse transcriptase–polymerase chain reaction. Results: There was a significant early and progressive cardiomyocyte lipid accumulation in DM but not in non-DM recipients (p = 0.019). In the subgroup receiving metformin, independently from immunosuppressive therapy that was similar among groups, lipid accumulation was reduced in comparison with DM recipients not receiving the drug (hazard ratio: 6.597; 95% confidence interval: 2.516 to 17.296; p < 0.001). Accordingly, lipotoxic factors were increased in DM versus non-DM recipients, and, relevantly, metformin use was associated with fewer lipotoxic factors. Conclusions: Early pathogenesis of human DMCM started with cardiomyocyte lipid accumulation following HTX in DM recipients. Metformin use was associated with reduced lipid accumulation independently of immunosuppressive therapy. This may constitute a novel target for therapy of DMCM

    Exercise promotes angiogenesis and improves beta-adrenergic receptor signalling in the post-ischaemic failing rat heart.

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    We investigated whether exercise training could promote angiogenesis and improve blood perfusion and left ventricular (LV) remodelling of the post-myocardial infarction (MI) failing heart. We also explored the contribution of ameliorated beta-adrenergic receptor signalling and function on the overall improvement of cardiac contractility reserve induced by exercise.Adult Wistar male rats were randomly assigned to one of four experimental groups. Sham-operated and post-MI heart failure (HF) rats were housed under sedentary conditions or assigned to 10-weeks of a treadmill exercise protocol. At 4 weeks after MI, sedentary HF rats showed LV eccentric hypertrophy, marked increase of LV diameters associated with severely impaired fractional shortening (14 +/- 5\%), increased LV end diastolic pressure (20.9 +/- 2.6 mmHg), and pulmonary congestion. In addition, cardiac contractile responses to adrenergic stimulation were significantly blunted. In trained HF rats, exercise was able to (i) reactivate the cardiac vascular endothelial growth factor pathway with a concurrent enhancement of myocardial angiogenesis, (ii) significantly increase myocardial perfusion and coronary reserve, (iii) reduce cardiac diameters, and (iv) improve LV contractility in response to adrenergic stimulation. This latter finding was also associated with a significant improvement of cardiac beta-adrenergic receptor downregulation and desensitization.Our data indicate that exercise favourably affects angiogenesis and improves LV remodelling and contractility reserve in a rat model of severe chronic HF

    Glycated ACE2 reduces anti-remodeling effects of renin-angiotensin system inhibition in human diabetic hearts

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    Background: High glycated-hemoglobin (HbA1c) levels correlated with an elevated risk of adverse cardiovascular outcomes despite renin-angiotensin system (RAS) inhibition in type-2 diabetic (T2DM) patients with reduced ejection fraction. Using the routine biopsies of non-T2DM heart transplanted (HTX) in T2DM recipients, we evaluated whether the diabetic milieu modulates glycosylated ACE2 (GlycACE2) levels in cardiomyocytes, known to be affected by non-enzymatic glycosylation, and the relationship with glycemic control. Objectives: We investigated the possible effects of GlycACE2 on the anti-remodeling pathways of the RAS inhibitors by evaluating the levels of Angiotensin (Ang) 1–9, Ang 1–7, and Mas receptor (MasR), Nuclear-factor of activated T-cells (NFAT), and fibrosis in human hearts. Methods: We evaluated 197 first HTX recipients (107 non-T2DM, 90 T2DM). All patients were treated with angiotensin-converting enzyme inhibitor (ACE-I) or angiotensin receptor blocker (ARB) at hospital discharge. Patients underwent clinical evaluation (metabolic status, echocardiography, coronary CT-angiography, and endomyocardial biopsies). Biopsies were used to evaluate ACE2, GlycACE2, Ang 1–9, Ang 1–7, MasR, NAFT, and fibrosis. Results: GlycACE2 was higher in T2DM compared tonon-T2DM cardiomyocytes. Moreover, reduced expressions of Ang 1–9, Ang 1–7, and MasR were observed, suggesting impaired effects of RAS-inhibition in diabetic hearts. Accordingly, biopsies from T2DM recipients showed higher fibrosis than those from non-T2DM recipients. Notably, the expression of GlycACE2 in heart biopsies was strongly dependent on glycemic control, as reflected by the correlation between mean plasma HbA1c, evaluated quarterly during the 12-month follow-up, and GlycACE2 expression. Conclusion: Poor glycemic control, favoring GlycACE2, may attenuate the cardioprotective effects of RAS-inhibition. However, the achievement of tight glycemic control normalizes the anti-remodeling effects of RAS-inhibition

    A modern network approach to revisiting the positive and negative affective schedule (PANAS) construct validity

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    Introduction: The factor structure of the Positive and Negative Affective Schedule (PANAS) is still a topic of debate. There are several reasons why using Exploratory Graph Analysis (EGA) for scale validation is advantageous and can help understand and resolve conflicting results in the factor analytic literature. Objective: The main objective of the present study was to advance the knowledge regarding the factor structure underlying the PANAS scores by utilizing the different functionalities of the EGA method. EGA was used to (1) estimate the dimensionality of the PANAS scores, (2) establish the stability of the dimensionality estimate and of the item assignments into the dimensions, and (3) assess the impact of potential redundancies across item pairs on the dimensionality and structure of the PANAS scores. Method: This assessment was carried out across two studies that included two large samples of participants. Results and Conclusion: In sum, the results are consistent with a two-factor oblique structure.Fil: Flores Kanter, Pablo Ezequiel. Universidad Empresarial Siglo XXI; Argentina. Consejo Nacional de Investigaciones CientĂ­ficas y TĂ©cnicas; ArgentinaFil: Garrido, Luis Eduardo. Pontificia Universidad CatĂłlica Madre y Maestra; RepĂșblica DominicanaFil: Moretti, Luciana SofĂ­a. Universidad Empresarial Siglo XXI; Argentina. Pontificia Universidad CatĂłlica Madre y Maestra; RepĂșblica Dominicana. Consejo Nacional de Investigaciones CientĂ­ficas y TĂ©cnicas; ArgentinaFil: Medrano, Leonardo. Universidad Empresarial Siglo XXI; Argentina. Pontificia Universidad CatĂłlica Madre y Maestra; RepĂșblica Dominicana. Consejo Nacional de Investigaciones CientĂ­ficas y TĂ©cnicas; Argentin

    Single-cell RNA sequencing reveals cancer stem-like cells and dynamics in tumor microenvironment during cholangiocarcinoma progression

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    Cholangiocarcinoma is a malignancy of the bile ducts that is driven by activities of cancer stem-like cells and characterized by a heterogeneous tumor microenvironment. To better understand the transcriptional profiles of cancer stem-like cells and dynamics in the tumor microenvironment during the progression of cholangiocarcinoma, we performed single-cell RNA analysis on cells collected from three different timepoints of tumorigenesis in a YAP/AKT mouse model. Bulk RNA sequencing data from TCGA (The Cancer Genome Atlas program) and ICGC cohorts were used to verify and support the finding. In vitro and in vivo experiments were performed to assess the stemness of cancer stem-like cells. We identified Tm4sf1high malignant cells as cancer stem-like cells. Across timepoints of cholangiocarcinoma formation in YAP/AKT mice, we found dynamic change in cancer stem-like cell/stromal/immune cell composition. Nevertheless, the dynamic interaction among cancer stem-like cells, immune cells, and stromal cells at different timepoints was elaborated. Collectively, these data serve as a useful resource for better understanding cancer stem-like cell and malignant cell heterogeneity, stromal cell remodeling, and immune cell reprogramming. It also sheds new light on transcriptomic dynamics during cholangiocarcinoma progression at single-cell resolution
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