PTEN and the PTEN-like phosphatase CnrN have both distinct and overlapping roles in a Dictyostelium chemorepulsion pathway.

Little is known about eukaryotic chemorepulsion. The enzymes phosphatase and tensin homolog (PTEN) and CnrN dephosphorylate phosphatidylinositol 3,4,5-trisphosphate [PI(3,4,5)P3] to phosphatidylinositol 4,5-bisphosphate [PI(4,5)P2]. Dictyostelium discoideum cells require both PTEN and CnrN to induce chemorepulsion of cells away from the secreted chemorepellent protein AprA.

PTEN and the PTEN-like phosphatase CnrN have both distinct and overlapping roles in a chemorepulsion pathway.

The directed movement of eukaryotic cells is crucial for processes such as embryogenesis and immune cell trafficking. The enzyme Phosphatase and tensin homolog (PTEN) dephosphorylates phosphatidylinositol 3,4,5-trisphosphate [PI(3,4,5)P ] to phosphatidylinositol 4,5-bisphosphate [PI(4,5)P ]. cells require both PTEN and the PTEN-like phosphatase CnrN to locally inhibit Ras activation to induce biased movement of cells away from the secreted chemorepellent protein AprA.

Cardiac Amyloidosis Imaging, Part 3: Interpretation, Diagnosis, and Treatment.

Cardiac amyloidosis was thought to be rare, undiagnosable, and incurable. However, recently it has been discovered to be common, diagnosable, and treatable. This knowledge has led to a resurgence in nuclear imaging with Tc-pyrophosphate-a scan once believed to be extinct-to identify cardiac amyloidosis, particularly in patients with heart failure but preserved ejection fraction.

Cardiac Amyloidosis Imaging, Part 1: Amyloidosis Etiology and Image Acquisition.

Cardiac amyloidosis is a systemic form of amyloidosis in which protein-based infiltrates are deposited in myocardial extracellular space. The accumulation of amyloid fibrils causes the myocardium to thicken and stiffen, leading to diastolic dysfunction and, eventually, heart failure. Until recently, cardiac amyloidosis was considered rare.

Cardiac Amyloidosis Imaging, Part 2: Quantification and Technical Considerations.

Tc-pyrophosphate imaging has been around for a long time. In the 1970s, it was used to image recent myocardial infarction. However, it has recently been recognized for its value in detecting cardiac amyloidosis, leading to widespread use across the United States.

Illness Incidence, Psychological Characteristics, and Sleep in Dogsled Drivers During the Iditarod Trail Sled Dog Race.

Introduction: Every March, dogsled drivers (mushers) compete in a 1569-km race across Alaska, involving physical exertion, mental exertion, and sleep deprivation for up to 2 wk. These factors may increase mushers' vulnerability to illness, making them a relevant study population for acute infection risk factors. Specifically, the influence of psychological factors on illness risk during prolonged physical exertion has rarely been investigated.

Sled dogs as a model for PM2.5 exposure from wildfires in Alaska.

Particulate matter 2.5 (PM2.5) exposure induces oxidative stress associated with many negative health outcomes such as respiratory disorders, cardiovascular disease and neurodegenerative disease.

Review of COVID-19 Myocarditis in Competitive Athletes: Legitimate Concern or Fake News?

Since the first reported case of COVID-19 in December 2019, the global landscape has shifted toward an unrecognizable paradigm. The sports world has not been immune to these ramifications; all major sports leagues have had abbreviated seasons, fan attendance has been eradicated, and athletes have opted out of entire seasons. For these athletes, cardiovascular complications of COVID-19 are particularly concerning, as myocarditis has been implicated in a significant portion of sudden cardiac death (SCD) in athletes (up to 22%).

Worldwide Variation in the Use of Nuclear Cardiology Camera Technology, Reconstruction Software, and Imaging Protocols.

Objectives: This study sought to describe worldwide variations in the use of myocardial perfusion imaging hardware, software, and imaging protocols and their impact on radiation effective dose (ED).

Background: Concerns about long-term effects of ionizing radiation have prompted efforts to identify strategies for dose optimization in myocardial perfusion scintigraphy. Studies have increasingly shown opportunities for dose reduction using newer technologies and optimized protocols.

Worldwide Diagnostic Reference Levels for Single-Photon Emission Computed Tomography Myocardial Perfusion Imaging: Findings From INCAPS.

Objectives: This study sought to establish worldwide and regional diagnostic reference levels (DRLs) and achievable administered activities (AAAs) for single-photon emission computed tomography (SPECT) myocardial perfusion imaging (MPI).

Background: Reference levels serve as radiation dose benchmarks to compare individual laboratories against aggregated data, helping to identify sites in greatest need of dose reduction interventions. DRLs for SPECT MPI have previously been derived from national or regional registries.

Current Status of Patient Radiation Exposure of Cardiac Positron Emission Tomography and Single-Photon Emission Computed Tomographic Myocardial Perfusion Imaging.

Background: Radiation exposure during nuclear cardiology procedures has received much attention and has prompted citations for radiation reduction. In 2010, the American Society of Nuclear Cardiology recommended reducing the average patient study radiation exposure to <9 mSv in 50% of studies by 2014. Cardiac positron emission tomography (PET) for myocardial perfusion imaging (MPI) has emerged within recent years, but current radiation exposure in cardiac nuclear PET laboratories is unknown.

Exercise Increases Glucose Transporter-4 Levels on Peripheral Blood Mononuclear Cells.

Purpose: Glucose transporter 4 (GLUT4) plays a key role in the pathophysiology of type 2 diabetes. Glucose transporter 4 is upregulated in response to exercise, enhancing cellular glucose transport in skeletal muscle tissue. This mechanism appears to remain intact in individuals with insulin resistance.

Healthcare Policy Statement on the Utility of Coronary Computed Tomography for Evaluation of Cardiovascular Conditions and Preventive Healthcare: From the Health Policy Working Group of the Society of Cardiovascular Computed Tomography.

The rising cost of healthcare is prompting numerous policy and advocacy discussions regarding strategies for constraining growth and creating a more efficient and effective healthcare system. Cardiovascular imaging is central to the care of patients at risk of, and living with, heart disease. Estimates are that utilization of cardiovascular imaging exceeds 20 million studies per year.

25(OH)D levels in trained versus sedentary university students at 64° north.

Purpose: 25-hydroxyvitamin D (25[OH]D) deficiency is associated with compromised bone mineralisation, fatigue, suppressed immune function and unsatisfactory skeletal muscle recovery. We investigated the risk of 25(OH)D insufficiency or deficiency in endurance athletes compared to sedentary non-athletes living at 64° north.

Methods: University student-athletes (TS) and sedentary students (SS) volunteered to participate in this study.

Nuclear Cardiology Practices and Radiation Exposure in the Oceania Region: Results From the IAEA Nuclear Cardiology Protocols Study (INCAPS).

Background: There is concern about radiation exposure with radionuclide myocardial perfusion imaging (MPI). This sub-study of the International Atomic Energy Agency (IAEA) Nuclear Cardiology Protocols Study reports radiation doses from MPI, and use of dose-optimisation protocols in Australia and New Zealand (ANZ), and compares them with data from the rest of the world.

Methods: Data were collected from 7911 MPI studies performed in 308 laboratories worldwide in one week in 2013, including 439 MPI studies from 34 ANZ laboratories.

Reconciling discordant myocardial perfusion imaging and coronary angiography.

A common clinical conundrum presents itself in the discordance between nuclear stress testing and invasive coronary angiography (ICA) in the patient presenting with angina. A patient with an abnormal perfusion scan and "normal coronary angiography" may result in the patient's symptoms being dismissed as "non-cardiac." Alternatively, a patient with a "normal perfusion study," who nonetheless undergoes ICA and is found to have significant coronary artery disease may confound efforts to risk stratify and potentially treat patients with angina.

Nationwide Laboratory Adherence to Myocardial Perfusion Imaging Radiation Dose Reduction Practices: A Report From the Intersocietal Accreditation Commission Data Repository.

Objectives: This study sought to examine current laboratory practices for radiation effective doses for myocardial perfusion imaging (MPI) and laboratory adherence to guideline-directed radiation reduction practices.

Background: A recent focus on radiation dose reduction for cardiovascular imaging has led to several published guidelines and consensus statements detailing performance metrics for laboratory practices. We sought to examine laboratory adherence to optimized radiation dose protocol recommendations among 5,216 submitted cases from 1,074 MPI laboratories evaluated for Intersocietal Accreditation Commission accreditation.

How Do Noninvasive Imaging Facilities Perceive the Accreditation Process? Results of an Intersocietal Accreditation Commission Survey.

The Intersocietal Accreditation Commission (IAC) accredits vascular, echocardiography, nuclear medicine, computed tomography, and magnetic resonance imaging laboratories. How facilities involved in the accreditation process view accreditation is unknown. The objective of this study was to examine the perception of laboratory accreditation from those who had undergone the process.

Current worldwide nuclear cardiology practices and radiation exposure: results from the 65 country IAEA Nuclear Cardiology Protocols Cross-Sectional Study (INCAPS).

Aims: To characterize patient radiation doses from nuclear myocardial perfusion imaging (MPI) and the use of radiation-optimizing 'best practices' worldwide, and to evaluate the relationship between laboratory use of best practices and patient radiation dose.

Methods And Results: We conducted an observational cross-sectional study of protocols used for all 7911 MPI studies performed in 308 nuclear cardiology laboratories in 65 countries for a single week in March-April 2013. Eight 'best practices' relating to radiation exposure were identified a priori by an expert committee, and a radiation-related quality index (QI) devised indicating the number of best practices used by a laboratory.

Facility perception of nuclear cardiology accreditation: Results of an Intersocietal Accreditation Commission (IAC) survey.

Background: The Medicare Improvements for Patients and Providers Act requires accreditation for all non-hospital suppliers of nuclear cardiology, nuclear medicine, and positron emission tomography (PET) studies as a condition of reimbursement. The perceptions of these facilities regarding the value and impact of the accreditation process are unknown. We conducted an electronic survey to assess the value of nuclear cardiology accreditation.

Patient-centered imaging: shared decision making for cardiac imaging procedures with exposure to ionizing radiation.

The current paper details the recommendations arising from an NIH-NHLBI/NCI-sponsored symposium held in November 2012, aiming to identify key components of a radiation accountability framework fostering patient-centered imaging and shared decision-making in cardiac imaging. Symposium participants, working in 3 tracks, identified key components of a framework to target critical radiation safety issues for the patient, the laboratory, and the larger population of patients with known or suspected cardiovascular disease. The use of ionizing radiation during an imaging procedure should be disclosed to all patients by the ordering provider at the time of ordering, and reinforced by the performing provider team.

ACCF/ASNC appropriateness criteria for single-photon emission computed tomography myocardial perfusion imaging (SPECT MPI): a report of the American College of Cardiology Foundation Quality Strategic Directions Committee Appropriateness Criteria Working Group and the American Society of Nuclear Cardiology endorsed by the American Heart Association.

Under the auspices of the American College of Cardiology Foundation (ACCF) and the American Society of Nuclear Cardiology (ASNC), an appropriateness review was conducted for radionuclide cardiovascular imaging (RNI), specifically gated single-photon emission computed tomography myocardial perfusion imaging (SPECT MPI). The review assessed the risks and benefits of the imaging test for several indications or clinical scenarios and scored them based on a scale of 1 to 9, where the upper range (7 to 9) implies that the test is generally acceptable and is a reasonable approach, and the lower range (1 to 3) implies that the test is generally not acceptable and is not a reasonable approach. The mid range (4 to 6) implies that the test may be generally acceptable and may be a reasonable approach for the indication.

Effects of clopidogrel and aspirin combination versus aspirin alone on platelet aggregation and major receptor expression in patients with heart failure: the Plavix Use for Treatment Of Congestive Heart Failure (PLUTO-CHF) trial.

Background: Persistent platelet activation may contribute to thrombotic events in patients with congestive heart failure (CHF). Chronic use of mild platelet inhibitors could therefore represent an independent avenue to improve morbidity, mortality, and quality of life in this expanding population. Although clopidogrel is widely used in patients with acute coronary syndromes and ischemic stroke, the ability of this novel ADP-receptor antagonist to inhibit platelet function in patients with CHF is unknown.