Priscilla M. Clarkson's research while affiliated with University of Massachusetts Amherst and other places

Publications (409)

Article
Insufficient 25-hydroxyvitamin D [(25(OH)D)] levels are associated with high resting blood pressure (BP). However, the relationship between 25(OH)D and the peak systolic BP (SBP) response to exercise, a predictor of future hypertension, has yet to be investigated. We sought to examine the relationship among serum 25(OH)D and the peak SBP response t...
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Background Interleukin‐15 (IL‐15) is a myokine associated with muscle strength, possibly by attenuating protein breakdown. A variant in the alpha‐receptor (IL‐15Rα 1775 A>C, rs2228059) partially modulates the muscle strength and size response to resistance training. We examined if this polymorphism associated with habitual physical activity among E...
Article
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Exertional (exercise-induced) rhabdomyolysis is a potentially life threatening condition that has been the subject of research, intense discussion, and media attention. The causes of rhabdomyolysis are numerous and can include direct muscle injury, unaccustomed exercise, ischemia, extreme temperatures, electrolyte abnormalities, endocrinologic cond...
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Glucocorticoid receptor (NR3C1) polymorphisms associate with obesity, muscle strength, and cortisol sensitivity. We examined associations among four NR3C1 polymorphisms and the muscle response to resistance training (RT). European-American adults (n = 602, 23.8±0.4yr) completed a 12 week unilateral arm RT program. Maximum voluntary contraction (MVC...
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The purpose of this study was to examine relationships between objective and self-report measures of physical activity and muscle strength among healthy adults ranging in age from 20 to 91 years. Participants (n = 412) were mostly Caucasian men (48 %) and women (52 %) 43.9 ± 16.1 year of age with a body mass index (BMI) of 26.4 ± 4.8 kg/m(2). Physi...
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Pericytes are skeletal muscle resident, multipotent stem cells that are localized to the microvasculature. In vivo, studies have shown that they respond to damage through activation of nuclear-factor kappa-B (NF-κB), but the downstream effects of NF-κB activation on endothelial cell proliferation and cell-cell signaling during repair remain unknown...
Article
This study determined the contribution of extracellular matrix (ECM) remodeling to the protective adaptation of human skeletal muscle known as the repeated-bout effect (RBE). Muscle biopsies were obtained 3 hours, 2 days, and 27 days following an initial bout (B1) of lengthening contractions (LCs) and 2 days following a repeated bout (B2) in 2 sepa...
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Statins are the most widely prescribed and effective medication for reducing low density lipoprotein cholesterol. Statins may also lower resting blood pressure (BP); however, results are inconsistent. We sought to determine if the maximum dose of atorvastatin reduces resting BP and the peak systolic BP (SBP) achieved on a graded exercise stress tes...
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The authors wish to thank Dr. Weijers (1) for his insightful comments on our article (2). Dr. Weijers is correct that most genetic variants identified using genome-wide association studies (GWAS) are not yet currently used in clinical practice to predict disease risk. Manolio et al. (3) addressed this lack of clinical use in an exquisite review in...
Article
Little information exists regarding the psychometric properties of question eight (Q8) of the Paffenbarger Physical Activity Questionnaire (PPAQ) to assess exercise. Thus, we conducted two studies to assess the validity and test-retest reliability of Q8 among adults. Study one participants (n=419) were 44.1±16.1 yr. Validity was determined by compa...
Article
Recreational activity frequently produces large increases in circulating CK activity without consequence. Thus, high CK levels alone do not portend renal failure. Most cases of exertional rhabdomyolysis can, and probably do, resolve on their own without treatment. When taking a blood sample during a routine check, for example in monitoring patients...
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Genome-wide association studies have identified thousands of variants that are associated with numerous phenotypes. One such variant, rs13266634, a non-synonymous single nucleotide polymorphism in the solute carrier family 30 (zinc transporter) member eight gene, is associated with a 53% increase in risk of developing type 2 diabetes. We hypothesiz...
Article
The present study examined if increases in creatine kinase (CK) levels during high-dose atorvastatin treatment are associated with changes in skeletal muscle function and symptoms. The Effect of Statins on Muscle Performance study (STOMP) investigated the effects of atorvastatin 80 mg daily for 6 months on muscle performance, exercise capacity, and...
Article
We investigated the existence of contralateral repeated bout effect (RBE) and tested if the attenuation of nuclear factor-kappa B (NF-κB; an important regulator of muscle inflammation) induction following eccentric exercise is a potential mechanism. Thirty-one healthy men performed two bouts of knee extension eccentric exercise, initially with one...
Conference Paper
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PURPOSE: Evidence is mixed regarding the associations of cardiometabolic risk factors and mental health. We examined these associations among healthy, adult men (n=74) and women (n=73). METHODS: Cardiometabolic risk factors were body mass index (BMI), waist circumference (WC), blood pressure (BP), and fasting blood lipids-lipoproteins. BMI was calc...
Article
Introduction: Skeletal muscle regeneration following damage relies on proliferation and differentiation of muscle precursor cells (MPCs). We recently observed increased NF-kB activity in vascular-associated muscle resident pericytes following muscle damage in humans. We determined how altered NF-kB activity in human primary pericytes (HPPs) affect...
Article
Three experiments examined the effectiveness of augmented feedback (AFB) on the performance of a relatively complex, applied task. The objective was to reduce foot pronation during barre exercise in dance. Experiment 1: Ten novice performers were assigned to either an AFB group or an appropriate control group and were tested on three days. A greate...
Article
The present experiment evaluated the effects of a 27-day sit up exercise training program on adipose cell size and adiposity. Fat biopsies were taken from the abdomen, subscapular, and gluteal sites by needle aspiration in 13 experimental and 6 control male subjects before and after a five days/week progressive training regimen. Day 1 consisted of...
Article
Purpose: An osteopontin (OPN; SPP1) gene promoter polymorphism modifies disease severity in Duchenne muscular dystrophy, and we hypothesized that it might also modify muscle phenotypes in healthy volunteers. Methods: Gene association studies were carried out for OPN (rs28357094) in the FAMuSS cohort (n = 752; mean ± SD age = 23.7 ± 5.7 yr). The...
Article
The flavonoid quercetin is purported to have potent antioxidant and anti-inflammatory properties. This study examined if quercetin supplementation attenuates indicators of exercise-induced muscle damage in a double-blind laboratory study. Thirty healthy subjects were randomized to quercetin (QU) or placebo (PL) supplementation and performed 2 separ...
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Objective. We examined the influence of missense polymorphism, endothelial nitric oxide synthase (NOS3) +894 G>T (rs1799983), on habitual physical activity (PA) and the muscle strength response to resistance training (RT). Methods. Men () and women (; yr) were genotyped. Subjects reported hr/wk in vigorous and light intensity PA and sitting on the...
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Background: Many clinicians believe that statins cause muscle pain, but this has not been observed in clinical trials, and the effect of statins on muscle performance has not been carefully studied. Methods and results: The Effect of Statins on Skeletal Muscle Function and Performance (STOMP) study assessed symptoms and measured creatine kinase,...
Article
Unlabelled: The objective of the study was to investigate the absorption of quercetin aglycone in 18 healthy human subjects administered via the following oral carrier systems: suspension of quercetin (quercetin QU995 powder in Tang(®) and spring water), nutritional bars (First Strike™), and chews (RealFX™ Q-Plus™). Subjects were divided into 3 gr...
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We investigated the influence of Leptin (LEP) and leptin receptor (LEPR) SNPs on habitual physical activity (PA) and body composition response to a unilateral, upper body resistance training (RT) program. European-derived American volunteers (men=111, women=131, 23.4±5.4yr, 24.4±4.6kg·m(-2)) were genotyped for LEP 19 G>A (rs2167270), and LEPR 326 A...
Article
Purpose: The purpose of the study was to examine the relation between serum 25-hydroxy vitamin D (25(OH)D) levels and muscle strength in 419 healthy men and women over a broad age range (20-76 yr). Methods: Isometric and isokinetic strength of the arms and legs was measured using computerized dynamometry, and its relation to vitamin D was tested...
Article
The flavonoid quercetin is purported to have potent antioxidant/anti-inflammatory properties. This study examined if quercetin supplementation attenuates indicators of exercise-induced muscle damage in a double-blind laboratory study. Thirty healthy subjects were randomized to quercetin (QU) or placebo (PL) supplementation and performed two separat...
Article
Ankyrin repeat domain 6 (ANKRD6) is a ubiquitous protein that associates with early development in mammals and is highly expressed in the brain, spinal cord, and heart of humans. We examined the role of 8 ANKRD6 single-nucleotide polymorphisms (SNPs) on muscle performance and habitual physical activity (PA). Single-nucleotide polymorphisms were 545...
Article
Hydroxymethylglutaryl-coenzyme A (HMG-CoA) reductase inhibitors, or statins, are widely used drugs for hyperlipidemia and are generally well-tolerated, but the can produce skeletal muscle toxicity. The molecular mechanisms driving statin myopathy are unknown. We investigated the effects of statin treatment and eccentric (damaging) exercise on trans...
Article
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Limited data exist on the molecular mechanisms that govern skeletal muscle regeneration in humans. This study characterized the early molecular alterations in humans to eccentric contractions (ECs), a stimulus known to induce a muscle regenerative response. Thirty-five subjects completed 100 ECs of the knee extensors with 1 leg, and muscle biopsies...
Article
INTRODUCTION: Rhabdomyolysis is a potentially serious condition caused by the release of excess muscle specific proteins into circulation following damaging exercise and is commonly indicated by very high levels of creatine kinase (CK) activity in the blood. Eccentric contractions can result in muscle damage and are used as a safe laboratory model...
Chapter
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This chapter reviews common genetic variants (single nucleotide polymorphisms; SNPs) that reportedly influence baseline and resistance training induced changes in skeletal muscle size and strength. Genetic variants associated with strength and size have been found in a structural gene (alpha-actinin 3), growth factor genes (e.g., insulin-like growt...
Article
Unlabelled: Recently, a genome-wide association study (GWAS) that identified eight single-nucleotide polymorphisms (SNPs) associated with BMI highlighted a possible neuronal influence on the development of obesity. We hypothesized these SNPs would govern the response of BMI and subcutaneous fat to resistance training in young individuals (age = 24...
Article
Genome-wide association studies (GWASs) have identified polymorphic loci associated with coronary artery disease (CAD) risk factors (i.e. serum lipids) in adult populations (42-69 y). We hypothesized that younger populations would show a greater relative genetic component due to fewer confounding variables. We examined the influence of 20 GWAS loci...
Article
Low cardiorespiratory fitness and low serum 25-hydroxy vitamin D (25[OH]D) levels are associated with increased cardiovascular and all-cause mortality, but whether low 25(OH)D is independently associated with cardiorespiratory fitness in healthy adults is not known. We examined 25(OH)D levels and fitness in 200 healthy adults participating in a dou...
Article
Baseline muscle size and muscle adaptation to exercise are traits with high variability across individuals. Recent research has implicated several chemokines and their receptors in the pathogenesis of many conditions that are influenced by inflammatory processes, including muscle damage and repair. One specific chemokine, chemokine (C-C motif) liga...
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Emerging data have revealed a negative association between adiposity and muscle quality (MQ). There is a lack of research to examine this interaction among young, healthy individuals, and to evaluate the contribution of adiposity to adaptation after resistance exercise (RE). The purpose of this investigation was to examine the influence of subcutan...
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Although short-term disuse does not result in measurable muscle atrophy, studies suggest that molecular changes associated with protein degradation may be initiated within days of the onset of a disuse stimulus. We examined the global gene expression patterns in sedentary men (n = 7, mean age ± SD = 22.1 ± 3.7 yr) following 48 h unloading (UL) via...
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Skeletal muscle atrophy is a significant health problem that results in decreased muscle size and function and has been associated with increases in oxidative stress. The molecular mechanisms that regulate muscle atrophy, however, are largely unknown. The metallothioneins (MT), a family of genes with antioxidant properties, have been found to be co...
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Converging lines of evidence suggest that AKT1 is a major mediator of the responses to insulin, insulin-like growth factor 1 (IGF1), and glucose. AKT1 also plays a key role in the regulation of both muscle cell hypertrophy and atrophy. We hypothesized that AKT1 variants may play a role in the endophenotypes that make up metabolic syndrome. We studi...
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Previous studies have reported associations of polymorphisms in the IGF1 gene with phenotypes of body composition (BC). The purpose of this study was to identify phenotypes of BC and physical function that were associated with the IGF1 promoter polymorphism (rs35767, −C1245T). Subjects from the Health, Aging, and Body Composition Study, white males...
Article
Hydroxymethylglutaryl-coenzyme A reductase inhibitors or statins are the most effective medications for reducing elevated concentrations of low-density lipoprotein cholesterol (LDL-C). Statins reduce cardiac events in patients with coronary artery disease and previously healthy persons. Current recommendations for LDL-C treatment goals indicate tha...