205 research outputs found

    The need of data harmonization to derive robust empirical relationships between soil conditions and vegetation.

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    Question: Is it possible to improve the general applicability and significance of empirical relationships between abiotic conditions and vegetation by harmonization of temporal data? Location: The Netherlands. Methods: Three datasets of vegetation, recorded after periods with different meteorological conditions, were used to analyze relationships between soil moisture regime (expressed by the mean spring groundwater level - MSLt calculated for different periods) and vegetation (expressed by the mean indicator value for moisture regime Fm). For each releve, measured groundwater levels were interpolated and extrapolated to daily values for the period 1970-2000 by means of an impulse-response model. Sigmoid regression lines between MSLt and Fm were determined for each of the three datasets and for the combined dataset. Results: A measurement period of three years resulted in significantly different relationships between Fm and MSLt for the three datasets (F-test,/? <0.05>. The three regression lines only coincided for the mean spring groundwater level computed over the period 1970-2000 (AfSLclimate) and thus provided a general applicable relationship. Precipitation surplus prior to vegetation recordings strongly affected the relationships. Conclusions: Harmonization of time series data (1) eliminates biased measurements, (2) results in generally applicable relationships between abiotic and vegetation characteristics and (3) increases the goodness of fit of these relationships. The presented harmonization procedure can be used to optimize many relationships between soil and vegetation characteristics. © IAVS; Opulus Press Uppsala

    Neutral Effects of Combined Treatment With GLP-1R Agonist Exenatide and MR Antagonist Potassium Canrenoate on Cardiac Function in Porcine and Murine Chronic Heart Failure Models

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    Background: Ischemia-reperfusion and cardiac remodeling is associated with cardiomyocyte death, excessive fibrosis formation, and functional decline, eventually resulting in heart failure (HF). Glucagon-like peptide (GLP)-1 agonists are reported to reduce apoptosis and myocardial infarct size after ischemia-reperfusion. Moreover, mineralocorticoid receptor antagonists (MRAs) have been described to reduce reactive fibrosis and improve cardiac function. Here, we investigated whether combined treatment with GLP-1R agonist exenatide and MRA potassium canrenoate could minimize cardiac injury and limit HF progression in animal models of chronic HF. Methods and Results: Forty female Topigs Norsvin pigs were subjected to 150 min balloon occlusion of the left anterior descending artery (LAD). Prior to reperfusion, pigs were randomly assigned to placebo or combination therapy (either low dose or high dose). Treatment was applied for two consecutive days or for 8 weeks with a continued high dose via a tunneled intravenous catheter. Using 2,3,5-Triphenyltetrazolium chloride (TTC) staining we observed that combination therapy did not affect the scar size after 8 weeks. In line, left ventricular volume and function assessed by three-dimensional (3D) echocardiography (baseline, 7 days and 8 weeks), and cardiac magnetic resonance imaging (CMR, 8 weeks) did not differ between experimental groups. In addition, 36 C57Bl/6JRj mice underwent permanent LAD-occlusion and were treated with either placebo or combination therapy prior to reperfusion, for two consecutive days via intravenous injection, followed by continued treatment via placement of osmotic mini-pumps for 28 days. Global cardiac function, assessed by 3D echocardiography performed at baseline, 7, 14, and 28 days, did not differ between treatment groups. Also, no differences were observed in cardiac hypertrophy, assessed by heart weight/bodyweight and heart weight/tibia length ratio. Conclusion: In the current study, combined treatment with GLP-1R agonist exenatide and MR antagonist potassium canrenoate did not show beneficial effects on cardiac remodeling nor resulted in functional improvement in a small and large animal chronic HF model

    Sustained Delivery of Insulin-Like Growth Factor-1/Hepatocyte Growth Factor Stimulates Endogenous Cardiac Repair in the Chronic Infarcted Pig Heart

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    Activation of endogenous cardiac stem/progenitor cells (eCSCs) can improve cardiac repair after acute myocardial infarction. We studied whether the in situ activation of eCSCs by insulin-like growth factor 1 (IGF-1) and hepatocyte growth factor (HGF) could be increased using a newly developed hydrogel in chronic myocardial infarction (MI). One-month post-MI pigs underwent NOGA-guided intramyocardial injections of IGF-1/HGF (GF: both 0.5 ÎŒg/mL, n = 5) or IGF-1/HGF incorporated in UPy hydrogel (UPy-GF; both 0.5 ÎŒg/mL, n = 5). UPy hydrogel without added growth factors was administered to four control (CTRL) pigs. Left ventricular ejection fraction was increased in the UPy-GF and GF animals compared to CTRLs. UPy-GF delivery reduced pathological hypertrophy, led to the formation of new, small cardiomyocytes, and increased capillarization. The eCSC population was increased almost fourfold in the border zone of the UPy-GF-treated hearts compared to CTRL hearts. These results show that IGF-1/HGF therapy led to an improved cardiac function in chronic MI and that effect size could be further increased by using UPy hydrogel. Electronic supplementary material The online version of this article (doi:10.1007/s12265-013-9518-4) contains supplementary material, which is available to authorized users

    Comparing Conventional Chemotherapy to Chronomodulated Chemotherapy for Cancer Treatment: Protocol for a Systematic Review

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    Background: Chronomodulated chemotherapy aims to achieve maximum drug safety and efficacy by adjusting the time of treatment to an optimal biological time as determined by the circadian clock. Although it is a promising alternative to conventional (non–time-stipulated) chemotherapy in several instances, the lack of scientific consensus and the increased logistical burden of timed administration limit the use of a chronomodulated administration protocol. Objective: With the goal to increase scientific consensus on this subject, we plan to conduct a systematic review of the current literature to compare the drug safety and efficacy of chronomodulated chemotherapy with those of conventional chemotherapy. Methods: This systematic review will comply with the PRISMA (Preferred Reporting Items for the Systematic Reviews and Meta-Analysis) guidelines. In order to identify relevant studies, we conducted a comprehensive search in PubMed and Embase on May 18, 2020. We included clinical studies that compare either the safety or efficacy of chronomodulated chemotherapy with that of conventional chemotherapy. Potential studies will be reviewed and screened by 2 independent reviewers. Quality assessment will be performed using the National Institutes of Health’s Study Quality Assessment Tool (Quality Assessment of Controlled Intervention Studies). Disagreements will be resolved by consulting a third independent reviewer. Results: This protocol has received funding, and the search for studies from databases commenced on May 18, 2020. The systematic review is planned to be completed by October 31, 2020. Conclusions: In this systematic review, we will compare drug safety and drug efficacy for cancer patients who were administered either chronomodulated chemotherapy or conventional chemotherapy. Moreover, we will highlight the outcomes and quality of the selected trials for this review

    Generation and characterization of novel human induced pluripotent stem cell (iPSC) lines originating from five asymptomatic individuals carrying the PLN-R14del pathogenic variant and a non-carrier relative

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    The rare genetic alteration PLN-c.(40_42delAGA), leading to the deletion of arginine 14 (p.R14del) in phospholamban, is associated with dilated and arrhythmogenic cardiomyopathies occurring in early-adulthood. However, some carriers remain asymptomatic with normal lifespans. Here, we report human induced pluripotent stem cell (iPSC) lines generated from peripheral blood mononuclear cells (PBMCs) of five PLN-R14del carriers, who were asymptomatic at the time of blood collection, and one non-carrier family member. Each line exhibited typical iPSC morphology, pluripotency markers, and tri-lineage differentiation. These cell lines provide a valuable model to investigate the mechanisms underlying the onset, progression, and patient-specific resistance to PLN-R14del-induced cardiomyopathy

    The 10th Biennial Hatter Cardiovascular Institute workshop: cellular protection—evaluating new directions in the setting of myocardial infarction, ischaemic stroke, and cardio-oncology

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    Due to its poor capacity for regeneration, the heart is particularly sensitive to the loss of contractile cardiomyocytes. The onslaught of damage caused by ischaemia and reperfusion, occurring during an acute myocardial infarction and the subsequent reperfusion therapy, can wipe out upwards of a billion cardiomyocytes. A similar program of cell death can cause the irreversible loss of neurons in ischaemic stroke. Similar pathways of lethal cell injury can contribute to other pathologies such as left ventricular dysfunction and heart failure caused by cancer therapy. Consequently, strategies designed to protect the heart from lethal cell injury have the potential to be applicable across all three pathologies. The investigators meeting at the 10th Hatter Cardiovascular Institute workshop examined the parallels between ST-segment elevation myocardial infarction (STEMI), ischaemic stroke, and other pathologies that cause the loss of cardiomyocytes including cancer therapeutic cardiotoxicity. They examined the prospects for protection by remote ischaemic conditioning (RIC) in each scenario, and evaluated impasses and novel opportunities for cellular protection, with the future landscape for RIC in the clinical setting to be determined by the outcome of the large ERIC-PPCI/CONDI2 study. It was agreed that the way forward must include measures to improve experimental methodologies, such that they better reflect the clinical scenario and to judiciously select combinations of therapies targeting specific pathways of cellular death and injury

    Long COVID and the cardiovascular system—elucidating causes and cellular mechanisms in order to develop targeted diagnostic and therapeutic strategies: a joint Scientific Statement of the ESC Working Groups on Cellular Biology of the Heart and Myocardial and Pericardial Diseases

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    Long COVID has become a world-wide, non-communicable epidemic, caused by long-lasting multiorgan symptoms that endure for weeks or months after SARS-CoV-2 infection has already subsided. This scientific document aims to provide insight into the possible causes and therapeutic options available for the cardiovascular manifestations of long COVID. In addition to chronic fatigue, which is a common symptom of long COVID, patients may present with chest pain, ECG abnormalities, postural orthostatic tachycardia, or newly developed supraventricular or ventricular arrhythmias. Imaging of the heart and vessels has provided evidence of chronic, post-infectious perimyocarditis with consequent left or right ventricular failure, arterial wall inflammation, or microthrombosis in certain patient populations. Better understanding of the underlying cellular and molecular mechanisms of long COVID will aid in the development of effective treatment strategies for its cardiovascular manifestations. A number of mechanisms have been proposed, including those involving direct effects on the myocardium, microthrombotic damage to vessels or endothelium, or persistent inflammation. Unfortunately, existing circulating biomarkers, coagulation, and inflammatory markers, are not highly predictive for either the presence or outcome of long COVID when measured 3 months after SARS-CoV-2 infection. Further studies are needed to understand underlying mechanisms, identify specific biomarkers, and guide future preventive strategies or treatments to address long COVID and its cardiovascular sequelae

    Unfolded Protein Response as a Compensatory Mechanism and Potential Therapeutic Target in PLN R14del Cardiomyopathy

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    BACKGROUND: Phospholamban (PLN) is a critical regulator of calcium cycling and contractility in the heart. The loss of arginine at position 14 in PLN (R14del) is associated with dilated cardiomyopathy with a high prevalence of ventricular arrhythmias. How the R14 deletion causes dilated cardiomyopathy is poorly understood, and there are no disease-specific therapies. METHODS: We used single-cell RNA sequencing to uncover PLN R14del disease mechanisms in human induced pluripotent stem cells (hiPSC-CMs). We used both 2-dimensional and 3-dimensional functional contractility assays to evaluate the impact of modulating disease-relevant pathways in PLN R14del hiPSC-CMs. RESULTS: Modeling of the PLN R14del cardiomyopathy with isogenic pairs of hiPSC-CMs recapitulated the contractile deficit associated with the disease in vitro. Single-cell RNA sequencing revealed the induction of the unfolded protein response (UPR) pathway in PLN R14del compared with isogenic control hiPSC-CMs. The activation of UPR was also evident in the hearts from PLN R14del patients. Silencing of each of the 3 main UPR signaling branches (IRE1, ATF6, or PERK) by siRNA exacerbated the contractile dysfunction of PLN R14del hiPSC-CMs. We explored the therapeutic potential of activating the UPR with a small molecule activator, BiP (binding immunoglobulin protein) inducer X. PLN R14del hiPSC-CMs treated with BiP protein inducer X showed a dose-dependent amelioration of the contractility deficit in both 2-dimensional cultures and 3-dimensional engineered heart tissues without affecting calcium homeostasis. CONCLUSIONS: Together, these findings suggest that the UPR exerts a protective effect in the setting of PLN R14del cardiomyopathy and that modulation of the UPR might be exploited therapeutically

    Pulsed radiofrequency treatment in interventional pain management: mechanisms and potential indications—a review

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    Item does not contain fulltextBACKGROUND: The objective of this review is to evaluate the efficacy of Pulsed Radiofrequency (PRF) treatment in chronic pain management in randomized clinical trials (RCTs) and well-designed observational studies. The physics, mechanisms of action, and biological effects are discussed to provide the scientific basis for this promising modality. METHODS: We systematically searched for clinical studies on PRF. We searched the MEDLINE (PubMed) and EMBASE database, using the free text terms: pulsed radiofrequency, radio frequency, radiation, isothermal radiofrequency, and combination of these. We classified the information in two tables, one focusing only on RCTs, and another, containing prospective studies. Date of last electronic search was 30 May 2010. The methodological quality of the presented reports was scored using the original criteria proposed by Jadad et al. FINDINGS: We found six RCTs that evaluated the efficacy of PRF, one against corticosteroid injection, one against sham intervention, and the rest against conventional RF thermocoagulation. Two trials were conducted in patients with lower back pain due to lumbar zygapophyseal joint pain, one in cervical radicular pain, one in lumbosacral radicular pain, one in trigeminal neuralgia, and another in chronic shoulder pain. CONCLUSION: From the available evidence, the use of PRF to the dorsal root ganglion in cervical radicular pain is compelling. With regards to its lumbosacral counterpart, the use of PRF cannot be similarly advocated in view of the methodological quality of the included study. PRF application to the supracapular nerve was found to be as efficacious as intra-articular corticosteroid in patients with chronic shoulder pain. The use of PRF in lumbar facet arthropathy and trigeminal neuralgia was found to be less effective than conventional RF thermocoagulation techniques

    Increased circulating IgG levels, myocardial immune cells and IgG deposits support a role for an immune response in pre- and end-stage heart failure

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    The chronic inflammatory response plays an important role in adverse cardiac remodelling and the development of heart failure (HF). There is also evidence that in the pathogenesis of several cardiovascular diseases, chronic inflammation is accompanied by antibody and complement deposits in the heart, suggestive of a true autoimmune response. However, the role of antibody-mediated immune responses in HF progression is less clear. We assessed whether immune cell infiltration and immunoglobulin levels are associated with HF type and disease stage, taking sex differences into account. We found IgG deposits and increased infiltration of immune cells in the affected myocardium of patients with end-stage HF with reduced ejection fraction (HFrEF, n = 20). Circulating levels of IgG1 and IgG3 were elevated in these patients. Furthermore, the percentage of transitional/regulatory B cells was decreased (from 6.9% to 2.4%) compared with healthy controls (n = 5). Similarly, increased levels of circulating IgG1 and IgG3 were observed in men with left ventricular diastolic dysfunction (LVDD, n = 5), possibly an early stage of HF with preserved EF (HFpEF). In conclusion, IgG deposits and infiltrates of immune cells are present in end-stage HFrEF. In addition, both LVDD patients and end-stage HFrEF patients show elevated levels of circulating IgG1 and IgG3, suggesting an antibody-mediated immune response upon cardiac remodelling, which in the early phase of remodelling appear to differ between men and women. These immunoglobulin subclasses might be used as marker for pre-stage HF and its progression. Future identification of auto-antigens might open possibilities for new therapeutic interventions
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