Lewis C. Becker
A5054563950- Cardiac Imaging and Diagnostics
- Genetic Associations and Epidemiology
- Cardiovascular Function and Risk Factors
- Cardiac Ischemia and Reperfusion
- Antiplatelet Therapy and Cardiovascular Diseases
- Advanced MRI Techniques and Applications
- Cardiac electrophysiology and arrhythmias
- Platelet Disorders and Treatments
- Acute Myocardial Infarction Research
- Cardiovascular and exercise physiology
- Lipoproteins and Cardiovascular Health
- Heart Rate Variability and Autonomic Control
- Cardiovascular Disease and Adiposity
- Cardiovascular Health and Disease Prevention
- Cerebrovascular and Carotid Artery Diseases
- Cardiovascular Health and Risk Factors
- Atherosclerosis and Cardiovascular Diseases
- Medical Imaging Techniques and Applications
- Coronary Interventions and Diagnostics
- Advanced X-ray and CT Imaging
- Cardiovascular Effects of Exercise
- Diabetes, Cardiovascular Risks, and Lipoproteins
- Diabetes Treatment and Management
- Nitric Oxide and Endothelin Effects
- Genomics and Rare Diseases
Johns Hopkins University
2016-2025
Johns Hopkins Medicine
2016-2025
Johns Hopkins Hospital
1985-2025
University of Baltimore
1978-2024
University of Oxford
2023
National Institutes of Health
1986-2021
National Institute on Aging
1989-2021
Beth Israel Deaconess Medical Center
2021
Becker College
2011-2018
Copenhagen University Hospital
2016
Abstract The Trans-Omics for Precision Medicine (TOPMed) programme seeks to elucidate the genetic architecture and biology of heart, lung, blood sleep disorders, with ultimate goal improving diagnosis, treatment prevention these diseases. initial phases focused on whole-genome sequencing individuals rich phenotypic data diverse backgrounds. Here we describe TOPMed goals design as well available resources early insights obtained from sequence data. include a variant browser, genotype...
Platelet glycoprotein IIb/IIIa is a membrane receptor for fibrinogen and von Willebrand factor, it has an important role in platelet aggregation. It known to be involved the pathogenesis of acute coronary syndromes. Previously, we found high frequency particular polymorphism, Pl A2 , gene encoding IIIa kindreds with prevalence premature myocardial infarction.
Nearly half of patients with heart failure have a preserved ejection fraction (HFpEF). Symptoms exercise intolerance and dyspnea are most often attributed to diastolic dysfunction; however, impaired systolic and/or arterial vasodilator reserve under stress could also play an important role.Patients HFpEF (n=17) control subjects without (n=19) generally matched for age, gender, hypertension, diabetes mellitus, obesity, the presence left ventricular hypertrophy underwent maximal-effort upright...
To assess the effect of age on cardiac volumes and function in absence overt or occult coronary disease, we performed serial gated blood pool scans at rest during progressive upright bicycle exercise to exhaustion 61 participants Baltimore Longitudinal Study Aging. The subjects ranged from 25 79 years were free disease according their histories results physical, resting stress electrocardiographic, thallium scintigraphic examinations. Absolute left ventricular obtained each workload. There...
To examine whether age differentially modifies the physiological response to exercise in men and women, we performed gated radionuclide ventriculography with measurement of left ventricular volumes at rest during peak upright cycle 200 rigorously screened healthy sedentary volunteers (121 79 women) aged 22–86 yr from Baltimore Longitudinal Study Aging. At sitting position, age-associated declines heart rate (HR) increases systolic blood pressure occurred both sexes. Whereas resting cardiac...
Microvascular obstruction within an area of myocardial infarction indicates worse functional recovery and a higher risk postinfarction complications. After prolonged coronary occlusion, contrast-enhanced MRI identifies as hyperenhanced region containing hypoenhanced core. Because the time course microvascular after infarction/reperfusion is unknown, we examined whether reaches its full extent shortly reperfusion or shows significant progression over following 2 days.Seven dogs underwent...
Background Contrast-enhanced fast magnetic resonance (MR) images of acute, reperfused human infarcts demonstrate regions hypoenhancement and hyperenhancement. The relations between the spatial extent time course these enhancement patterns to myocardial risk, infarct, no-reflow have not been well characterized. Methods Results proximal left anterior descending coronary artery was occluded in 11 closed-chest dogs for 90 minutes followed by 2 days reperfusion. Regional blood flow determined use...
NO. is a free radical that modulates heart function and metabolism. We report neuronal-type NO synthase (NOS) located on cardiac sarcoplasmic reticulum (SR) membrane vesicles endogenous produced by SR-associated NOS inhibits SR Ca2+ uptake. Ca2+-dependent biochemical conversion of L-arginine to L-citrulline was observed from isolated rabbit in the presence substrates cofactors. Endogenous generated detected electron paramagnetic resonance spin-trapping measurements. Immunoelectron microscopy...
The "no-reflow" phenomenon, the occurrence of areas with very low flow in hearts reperfused after ischemia, is thought to be largely established at time reperfusion as a result microvascular damage induced by ischemia. In present study we sought determine whether additional impairment tissue perfusion might also occur during course reperfusion. Open-chest dogs were subjected 90 minutes left circumflex coronary artery occlusion and for 2 (n = 7) or 3.5 hours 8). Myocardial was visualized...
Radioactive microspheres were used to estimate the changes in regional myocardial blood flow occurring during acute ischemia. Carbonized 15-µ spheres injected into left atrium of 28 open-chest dogs and radioactivity selected areas determined after sacrifice. Acute occlusion circumflex coronary artery produced a significant diminution proportion reaching area. In addition, there was disproportionate decrease endocardial ischemic area (endocardial/epicardial ratio falling from 1.17 0.76, P...
The Animal Models for Protecting Ischemic Myocardium Study was undertaken the purpose of developing reproducible animal models that could be used to assess interventions designed limit infarct size. This paper describes results obtained in an unconscious dog model and a conscious model, developed three participating laboratories. involving reperfusion after 3 hours ischemia open-chest dogs, intended determine whether therapy followed by early would size more than alone. chronically...
To determine the importance of reperfusion injury and ability free-radical scavenger recombinant human superoxide dismutase (h-SOD) to prevent it, open-chest dogs underwent 90 min proximal circumflex coronary artery occlusion, only at moment received either h-SOD (400,000 IU bolus into left atrium followed by a 300,000 iv infusion over 1 hr) or saline. After 48 hr surviving animals were killed measurements made risk region (by postmortem angiography) infarct size gross pathology). All...
The amino acid L-arginine is a substrate for nitric oxide synthase and increasingly used as health supplement. Prior studies suggest that has the potential to reduce vascular stiffness.To determine whether addition of standard postinfarction therapy reduces stiffness improves ejection fraction over 6-month follow-up in patients following acute ST-segment elevation myocardial infarction.Single-center, randomized, double-blind, placebo-controlled trial with enrollment from February 2002 June...
The conditions for coronary steal were determined using the two vasodilators--dipyridamole and nitroglycerin--in anesthetized dogs after ligation of left anterior descending artery (LAD). Previous studies have shown that when non-ligated arteries are normal, collateral flow increases dipyridamole. This study utilized a model in which distal LAD was ligated proximal circumflex (LC) stenosed. Heart rate blood pressure kept constant. In 20 dogs, 1-1.5 mg/kg dipyridamole caused decrease to...
Background— Multidetector computed tomography coronary angiography (CTA) is a robust method for the noninvasive diagnosis of artery disease. However, in its current form, CTA limited prediction myocardial ischemia. The purpose this study was to test whether adenosine stress perfusion imaging (CTP), when added CTA, can predict abnormalities caused by obstructive atherosclerosis. Methods and Results— Forty patients with history abnormal single-photon emission (SPECT-MPI) underwent 64-row...
A major challenge in genome-wide association studies (GWASs) is to derive the multiple testing threshold when hypothesis tests are conducted using a large number of single nucleotide polymorphisms. Permutation considered gold standard adjustment genetic studies. However, it computationally intensive, especially for GWASs, and can be impractical if random shuffles used ensure accuracy. Many researchers have developed approximation algorithms relieve computing burden imposed by permutation....
Most genome-wide association and fine-mapping studies to date have been conducted in individuals of European descent, genetic populations Hispanic/Latino African ancestry are limited. In addition, these more complex linkage disequilibrium structure. order better define the architecture understudied populations, we leveraged >100,000 phased sequences available from deep-coverage whole genome sequencing through multi-ethnic NHLBI Trans-Omics for Precision Medicine (TOPMed) program impute...