Στην βιολογία, το περιβάλλον μπορεί να καθοριστεί σαν ενα σύνολο κλιματικών, βιοτικών, κοινωνικών και εδαφικών παραγόντων που δρουν σε έναν οργανισμό και καθορίζουν την ανάπτυξη και την επιβίωση του. Έτσι, περιλαμβάνει οτιδήποτε μπορεί να επηρεάσει άμεσα τον μεταβολισμό ή τη συμπεριφορά των ζωντανών οργανισμών ή ειδών, όπως το φως, ο αέρας, το νερό, το έδαφος και άλλοι παράγοντες. Δείτε επίσης το άρθρο για το φυσικό περιβάλλον και τη φυσική επιλογή.
Στην αρχιτεκτονική, την εργονομία και την ασφάλεια στην εργασία, περιβάλλον είναι το σύνολο των χαρακτηριστικών ενός δωματίου ή κτιρίου που επηρεάζουν την ποιότητα ζωής και την αποδοτικότητα, περιλαμβανομένων των διαστάσεων και της διαρρύθμισης των χώρων διαβίωσης και της επίπλωσης, του φωτισμού, του αερισμού, της θερμοκρασίας, του θορύβου κλπ. Επίσης μπορεί να αναφέρεται στο σύνολο των δομικών κατασκευών. Δείτε επίσης το άρθρο για το δομημένο περιβάλλον.
Στην ψυχολογία, περιβαλλοντισμός είναι η θεωρία ότι το περιβάλλον (με τη γενική και κοινωνική έννοια) παίζει μεγαλύτερο ρόλο από την κληρονομικότητα καθορίζοντας την ανάπτυξη ενός ατόμου. Συγκεκριμένα, το περιβάλλον είναι ένας σημαντικός παράγοντας πολλών ψυχολογικών θεωριών.
Στην τέχνη, το περιβάλλον αποτελεί κινητήριο μοχλό και μούσα εμπνέοντας τους ζωγράφους ή τους ποιητές. Σε όλες τις μορφές της Τέχνης αποτελεί έμπνευση και οι Καλές Τέχνες φανερώνουν την επιρροή οπού άσκησε σε όλους τους καλλιτέχνες με όποιο είδος Τέχνης κι αν ασχολούνται. Ο άνθρωπος μέσα στο περιβάλλον δημιουργεί Μουσική, Ζωγραφική, Ποίηση, Γλυπτική, χορό, τραγούδι, θέατρο, αλλά και όλες οι μορφές τέχνης έχουν άμεση έμπνευση από το περιβάλλον.

Δευτέρα 24 Ιουνίου 2019

Cardiology

Renal Artery Stenosis and Congestive Heart Failure: What Do We Really Know?

Abstract

Purpose of Review

Congestive heart failure (CHF) is a major cause of morbidity, mortality, and health care expenditure. Although the role of renal artery stenosis (RAS) in CHF has been known, there are a number of areas of uncertainty.

Recent Findings

The prevalence of RAS in subjects with CHF varies from 15 to 54% depending on the cohort studied and the diagnostic modality used to identify RAS. In subjects with CHF, the presence of RAS is associated with worse renal function and a higher risk for mortality during long-term follow-up.

Summary

There are many unanswered questions regarding the role of RAS in subjects with CHF. This review highlights those questions and helps to set the research agenda in this area.



Strategies for Minimizing Occupational Radiation Exposure in Cardiac Imaging

Abstract

Purpose of Review

Radiation safety has been at the center of interest of both researchers and healthcare institutions. This review will summarize and shed light on the various techniques adapted to reduce staff exposure to ionizing radiation (IR) in the field of cardiac imaging.

Recent Findings

In the last years, with the advance of awareness and the development of new technologies, there have been several tools and techniques adapted. The breakthrough of several technologies to lower radiation dose and shorten the duration of diagnostic tests associated with IR, the use of protection devices by staff members, and mostly the awareness of exposure to IR are the hallmark of these advances. Using all these measures has led to a significant decrease in staff exposure to IR.

Summary

Reducing staff exposure to meet the "As Low As Reasonably Achievable" principle is feasible. This review introduces the most important strategies applied in cardiac imaging.



Pluripotent Stem Cell-Derived Cardiomyocyte Transplantation for Heart Disease Treatment

Abstract

Purpose of Review

Cardiovascular disease is the leading cause of mortality worldwide. Pluripotent stem cell-derived cardiomyocytes (PSC-CMs) have great potential to treat heart disease, owing to their capacity of engraftment and remuscularization in the host heart after transplantation. In the current review, we provide an overview of PSC-CMs for clinical transplantation.

Recent Findings

Studies have shown that PSC-CMs can survive, engraft, and form gap junctions after transplantation, with functional benefit. Engrafted PSC-CMs matured gradually in host hearts. Only in a large animal model, transient ventricular arrhythmias were detected, mainly because of the ectopic pacing from the grafted PSC-CMs. Although intense immunosuppression is unavoidable in xenotransplantation, immunosuppression remains necessary for MHC-matched allogenic non-human primate PSC-CMs transplantation.

Summary

This review offers insights on how PSC-CMs contribute to functional benefit after transplantation to injured non-human primate hearts. We believe that PSC-CM transplantation represents a potentially novel treatment for ischemic heart diseases, provided that several technological and biological limitations can be overcome.



Effect of SGLT2 Inhibitors on the Sympathetic Nervous System and Blood Pressure

Abstract

Purpose of the Review

Hyperactivity of sympathetic nervous system (SNS) plays a role in the development of arterial hypertension and heart failure, two co-morbidities frequently associated with type 2 diabetes (T2DM). This review aims at analyzing the effects of sodium-glucose cotransporter type 2 inhibitors (SGLT2is) on blood pressure and more especially on SNS activity in patients with T2DM.

Recent Findings

By enhancing glucosuria, natriuresis, and osmotic diuresis, SGLT2is improve glucose control, promote weight loss, lower arterial blood pressure, and reduce the risk of major cardiovascular events and hospitalization for heart failure. No rise of heart rate is detected despite reductions in blood pressure and plasma volume, which may suggest a dampening of SNS activity. Indeed, increasing experimental and clinical data demonstrated a reduction in SNS activity, including in key target organs such as the heart and the kidneys.

Summary

Of potential major interest, a better understanding of the mechanisms linking SGLT2 and SNS deserves further investigation.



Emerging Role of Coronary Computed Tomography Angiography in Lipid-Lowering Therapy: a Bridge to Image-Guided Personalized Medicine

Abstract

Purpose of Review

To summarize the current status of coronary computed tomography angiography (CTA) in the assessment of coronary plaques and discuss the ability of serial coronary CTA to quantitatively measure changes in the plaque burden in response to lipid-lowering therapy.

Recent Findings

Recent advances in coronary CTA have allowed identification of high-risk coronary features in acute coronary syndrome and measurement of changes in the coronary plaque burden with good reproducibility. Statin therapy may delay plaque progression and change some plaque features. However, the clinical relevance of quantitative changes in coronary plaques and the optimal methods to reduce the plaque burden remain unclear.

Summary

Despite guideline-directed lipid-lowering therapy, adverse events still occur in substantial numbers of patients receiving statins. Coronary CTA is noninvasive and has high diagnostic performance in patients with coronary artery disease, making change in the plaque burden an applicable biomarker for individualized assessment of future risk.



New Insights in the Control of Low-Density Lipoprotein Cholesterol to Prevent Cardiovascular Disease

Abstract

Purpose of Review

Low-density lipoprotein cholesterol (LDL-C) is one major cause of cardiovascular disease (CVD). In this review, we discuss current developments in the understanding of LDL-C as lifelong risk factor, treatment targets, and emerging approaches to reduce cardiovascular risk by lowering LDL-C.

Recent Findings

Recent evidence underscores the importance of LDL-C lowering in CVD prevention by mechanisms that increase the hepatic clearance of apolipoprotein B-containing lipoproteins from the plasma. Mendelian randomization studies provided evidence on both safety and efficacy of lower LDL-C in the long term. For young individuals, metrics other than 10-year CVD risk are required. Despite this evidence, LDL-C treatment target attainment is poor. Novel approaches are therefore needed. These include individualized strategies and new LDL-C-lowering pharmaceuticals.

Summary

Early, long-term treatment with LDL-C-lowering therapies has the potential to markedly reduce CVD incidence and progression. Future research should aim to identify patient characteristics that enable physicians to tailor therapy to each individual patient.



Genetics, Dyslipidemia, and Cardiovascular Disease: New Insights

Abstract

Purpose of Review

The cardiovascular (CV) risk related to lipid disorders is well established and is based on a robust body of evidence from well-designed randomized clinical trials, as well as prospective observational studies. In the last two decades, significant advances have been made in understanding the genetic basis of dyslipidemias. The present review is intended as a comprehensive discussion of current knowledge about the genetics and pathophysiology of disorders that predispose to dyslipidemia. We also focus on issues related to statins and the proprotein convertase subtilisin/kexin type 9 (PCSK9) and some of its polymorphisms, as well as new cholesterol-lowering medications, including PCSK9 inhibitors.

Recent Finding

Cholesterol is essential for the proper functioning of several body systems. However, dyslipidemia—especially elevated low-density lipoprotein (LDL-c) and triglyceride levels, as well as reduced lipoprotein lipase activity—is associated with an increased risk of coronary artery disease (CAD). High-density lipoprotein (HDL-c), however, seems to play a role as a risk marker rather than as a causal factor of the disease, as suggested by Mendelian randomization studies. Several polymorphisms in the lipoprotein lipase locus have been described and are associated with variations in the activity of this enzyme, producing high concentrations of triglycerides and increased risk of CAD.

Summary

Dyslipidemia, especially increased LDL-c and triglyceride levels, continues to play a significant role in CV risk. The combination of genetic testing and counseling is important in the management of patients with dyslipidemia of genetic etiology. Strategies focused on primary prevention can offer an opportunity to reduce CV events.



Time Is a Precious Commodity: 2018 OPTN Policy Change and the Potential to Lower Heart Transplant Waitlist Time in the Sickest Patients

Abstract

Purpose of Review

Heart transplantation is the gold standard therapy for end-stage heart failure; however, the donor pool is limited, making this a scarce resource that must be allocated to the sickest patients in an efficient, fair, and equitable manner. The allocation policies have been constantly revised over the years to refine the process. We will explore the new heart allocation system, OPTN-Policy 6, as well as, review why these changes were necessary.

Recent Findings

Over the past decade, the number of active heart transplant candidates nearly doubled, with a dramatic increase in the number of status 1A and 1B (high priority) candidates. Candidates have also faced increased waitlist times with geographic variances. The allocation policy changes will attempt to alleviate these problems as well as adapt to advances in technology.

Summary

The new allocation policy is designed to adapt to the present day reality of expanded mechanical support use, increased candidate acuity, increasing waiting times, and geographical disparities in transplant rates. Though the implementation of the new allocation policy will require some change in practice, the transplant community, as knowledge is gained, is accustomed to change and refinement in practice, in an effort to improve outcomes for patients with end-stage heart failure.



Left Atrial Occlusion Device Implantation: the Role of the Echocardiographer

Abstract

Purpose of Review

Atrial fibrillation is the most common arrhythmia worldwide and is a major risk factor for embolic stroke. For patients with atrial fibrillation who are unable to tolerate systemic anticoagulation, left atrial appendage (LAA) occlusion has been shown to mitigate stroke risk. In this article, we describe the vital role of the echocardiographer in intraprocedural guidance of percutaneous LAA occlusion procedures as well as in the pre- and post-procedure assessment of these patients.

Recent Findings

A few percutaneously delivered devices for LAA exclusion from the systemic circulation are available in contemporary practice. These devices employ an either exclusive endocardial LAA occlusion approach, such as the Watchman (Boston Scientific, Maple Grove, MN) and Amulet (St. Jude Medical, Minneapolis, MN), or both an endocardial and pericardial (epicardial) approach such as the Lariat procedure (SentreHEART, Palo Alto, CA).

Summary

Two- and three-dimension transesophageal echocardiography is critical for patient selection, procedure planning, procedural guidance, and ensuring satisfactory immediate as well as long-term LAA occlusion/exclusion efficacy. This review will provide an overview of the role of the echocardiographer in all aspects of LAA occlusion/exclusion procedures for the most commonly used commercially available devices in current practice.



Aortic Regurgitation

Abstract

Purpose of Review

Aortic regurgitation (AR) is a common form of valvular disease which is characterized by reflux of blood from the aorta into the left ventricle (LV) during diastole. AR results from various etiologies, affecting the aortic valve cusps or the aortic root. The clinical presentation of patients with AR depends on the severity of the regurgitation and differs whether AR develops acutely or if it progresses over a prolonged period, allowing the cardiac chambers to adapt. Echocardiography is the primary method to determine the etiology of AR and to define its severity. We review the current data regarding the diagnosis and treatment of AR.

Recent Findings

No single parameter is sufficient to determine AR severity; thus, an integrative, multi-parametric approach is required. Echocardiography is key for imaging the aortic valve morphology and flow as well as aortic root and ascending aorta. Determining LV ejection fraction and dimensions is essential for patient management and optimizing timing for intervention. Three-dimensional (3D) echocardiography is useful in the evaluation of AR etiology and severity. The use of Trasncatheter aortic valve replacement (TAVR) has emerged as an alternative to surgery in patients at high operative risk.

Summary

The diagnosis and management of AR requires a comprehensive approach and routine clinical and echocardiographic follow-up. Surgical or percutaneous therapy is indicated when symptoms develop and in those who have LV dysfunction or LV dilation.



Alexandros Sfakianakis
Anapafseos 5 . Agios Nikolaos
Crete.Greece.72100
2841026182
6948891480

Δεν υπάρχουν σχόλια:

Δημοσίευση σχολίου