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General Clinical Research Center (general + clinical_research_center)
Selected AbstractsThe effects of binge drinking on college students' next-day academic test-taking performance and mood stateADDICTION, Issue 4 2010Jonathan Howland ABSTRACT Aim To assess the effects of binge drinking on students' next-day academic test-taking performance. Design A placebo-controlled cross-over design with randomly assigned order of conditions. Participants were randomized to either alcoholic beverage [mean = 0.12 g% breath alcohol concentration (BrAC)] or placebo on the first night and then received the other beverage a week later. The next day, participants were assessed on test-taking, neurocognitive performance and mood state. Participants A total of 196 college students (,21 years) recruited from greater Boston. Setting The trial was conducted at the General Clinical Research Center at the Boston Medical Center. Measurements The Graduate Record Examinationsİ (GREs) and a quiz on a lecture presented the previous day measured test-taking performance; the Neurobehavioral Evaluation System (NES3) and the Psychomotor Vigilance Test (PVT) measured neurocognitive performance; and the Profile of Mood States (POMS) measured mood. Findings Test-taking performance was not affected on the morning after alcohol administration, but mood state and attention/reaction-time were affected. Conclusion Drinking to a level of 0.12 g% BrAC does not affect next-day test-taking performance, but does affect some neurocognitive measures and mood state. [source] Effects of Low-Dose Prednisone on Bone Metabolism,JOURNAL OF BONE AND MINERAL RESEARCH, Issue 3 2005Francine N Ton MD Abstract Prednisone 5 mg/day suppresses multiple indices of bone formation in a randomized placebo-controlled trial in healthy postmenopausal females. This suggests that even low doses of prednisone may reduce bone repair or renewal and may have adverse effects on bone mass and/or bone strength. Introduction: High doses of chronic glucocorticoids are known to have adverse effects on bone, and measures to prevent bone loss are well established for doses >7.5 mg daily, because these doses can cause premature or exaggerated osteoporosis. However, it is unclear if chronic prednisone doses of 5 mg daily have the same effects on bone. There are no established recommendations for preventing glucocorticoid-induced osteoporosis in people taking prednisone 5 mg daily, a dose used frequently in medical practice to treat diseases of the lungs, joints, skin, muscles, eyes, nerves, etc. Our primary objective was to test whether prednisone 5 mg daily affects serum and urine indices of bone metabolism in healthy postmenopausal women. Our secondary objectives were to determine if prednisone 5 mg affected systolic or diastolic blood pressure or causes side effects. Materials and Methods: A double-blinded randomized placebo-controlled 8-week trial in 50 healthy postmenopausal women was conducted at the Massachusetts General Hospital Outpatient General Clinical Research Center. Patients were randomly assigned to prednisone 5 mg daily or matching placebo for 6 weeks, followed by a 2-week recovery phase. Markers of bone formation and resorption were determined at weeks 0, 2, 4, 6, and 8. Indices of osteoblast activity included serum propeptide of type I N-terminal procollagen (PINP), propeptide of type I C-terminal procollagen (PICP), osteocalcin, and bone-specific alkaline phosphatase (BSALP). Indices of osteoclast activity included urine and serum type I collagen N-telopeptide (NTX) and free urinary deoxypyridinoline (DPD). Results and Conclusions: Prednisone rapidly and significantly decreased serum PINP (p < 0.01), PICP (p < 0.01), and osteocalcin (p < 0.01) and free urinary deoxypyridinoline (p = 0.017). These changes were largely reversed during the recovery period. Side effects were indistinguishable in the two groups. Neither systolic nor diastolic blood pressure changed significantly throughout the study between the two groups. In conclusion, low-dose prednisone significantly decreases indices of bone formation and may decrease indices of bone resorption in postmenopausal women. Further studies are needed to assess the effects of low-dose prednisone on BMD and fracture risk. [source] Fitness, fatness and activity as predictors of bone mineral density in older personsJOURNAL OF INTERNAL MEDICINE, Issue 5 2002K. J. Stewart Abstract. Stewart KJ, DeRegis JR, Turner KL, Bacher AC, Sung J, Hees PS, Tayback M, Ouyang P (Johns Hopkins Bayview Medical Center, Johns Hopkins University, School of Medicine, Baltimore, MD, USA). Fitness, fatness, and activity as predictors of bone mineral density in older persons. J Intern Med 2002; 252: 381,388. Objectives. To determine relationships of bone mineral density (BMD) with fitness, physical activity, and body composition and fat distribution. Design. Cross-sectional. Setting. General Clinical Research Center, Johns Hopkins Bayview Medical Center, Baltimore, Maryland. Subjects. Men (n = 38) and women (n = 46), aged 55,75 years with high normal blood pressure or mild hypertension but otherwise healthy. Methods. Aerobic fitness (oxygen uptake) on a treadmill, muscle strength by one-repetition maximum, activity by questionnaire, abdominal obesity by magnetic resonance imaging; anthropometrics, and body composition by dual energy X-ray absorptiometry (DXA) which measured total fat and lean mass, and BMD for the total skeleton, lumbar spine (L1,L4) and total hip. Results. Aerobic fitness did not correlate with BMD. Using multivariate analysis to ascertain independent contributions to the variance in BMD, in women, with adjustment for hormone replacement therapy (HRT), total skeleton BMD was independently related to muscle strength and abdominal total fat; total hip BMD to body weight; lumbar spine BMD to abdominal total fat. HRT also influenced BMD in the lumbar spine. In men, lumbar spine BMD was independently related to abdominal total fat physical activity and total hip BMD related to lower body strength. P < 0.05 for all of these correlations. Conclusions. Abdominal obesity and muscle strength emerge as predominant correlates of BMD in older persons with stronger relationships seen in women. Body weight and HRT also explained portions of the variance in BMD in women. Whether abdominal obesity is simply a marker for general obesity or has independent protective effects on bone is yet to be determined. [source] Diurnal variation of serum and urine biomarkers in patients with radiographic knee osteoarthritisARTHRITIS & RHEUMATISM, Issue 8 2006S. Y. Kong Objective To evaluate diurnal variation of biomarkers in subjects with osteoarthritis (OA) of the knee. Methods Twenty subjects with radiographic knee OA were admitted to the General Clinical Research Center of Duke University for an overnight stay to undergo serial blood and urine sampling. Biomarkers measured included serum hyaluronan (HA), cartilage oligomeric matrix protein (COMP), keratan sulfate (KS-5D4), aggrecan neoepitope (CS846), high-sensitivity C-reactive protein (hsCRP), osteocalcin, transforming growth factor ,1 (TGF,1), and type II collagen (CII),related epitopes (neoepitope from cleavage of CII [C2C], carboxy-terminus of three-quarter peptide from cleavage of CI and CII [C1,2C], and type II procollagen carboxy-propeptide [CPII] in serum, and C-terminal telopeptides of CII [CTX-II] and C2C in urine). Results Levels of serum HA, COMP, KS-5D4, and TGF,1 increased significantly from T0 (before arising from bed) to T1 (1 hour after arising). More diurnal variation in HA was observed in patients with higher daily mean HA concentrations. CPII increased significantly from T0 to T2 (4 hours after arising). Urinary concentrations of CTX-II were also found to vary with morning activity, decreasing significantly from T0 to T2. Urinary C2C concentrations increased significantly from T0 until T3 (early evening). No diurnal variations in CS846, hsCRP, osteocalcin, serum C2C, or C1,2C were observed. Six biomarkers (serum C2C, C1,2C, COMP, KS-5D4, TGF,1, and urinary CTX-II) were associated with radiographic knee OA (expressed as the sum of Kellgren/Lawrence radiographic severity grades), with the strongest correlations observed with measurements obtained at later time points (either T2 or T3). Conclusion Our study results suggest that serum and urine sampling for HA, COMP, KS-5D4, TGF,1, CPII, urinary CTX-II, and urinary C2C should be standardized in future OA clinical trials. Serum and urine sampling at late midday time points may be the optimal approach for OA studies, although this result should be validated in a larger cohort. [source] Change in leptin, body composition and other hormones around menarche , a visual representationACTA PAEDIATRICA, Issue 10 2008LG Bandini Abstract Aim: To present a visual representation of changes in body composition, leptin, insulin, estradiol and follicular stimulating hormone (FSH) levels in relation to menarche in girls. Methods: Participants were a subset of healthy girls (n = 108) enrolled in a longitudinal study of growth and development conducted at the General Clinical Research Center at the Massachusetts Institute of Technology (MIT). Participants were seen annually from before menarche until 4 years postmenarche for measures of body composition and serum levels of leptin, insulin, estradiol and FSH. Body composition was determined by bioelectrical impedance. Standardized body composition and hormone levels were smoothed and plotted relative to menarche to visualize patterns of change. Results: At menarche, the mean percentage body fat (%BF) of girls was 24.6% (SD = 4.1%) after menarche %BF was ,27%. Leptin levels averaged 8.4 ng/mL (SD = 4.6) at menarche and were ,12 ng/mL after menarche. Changes in leptin levels closely paralleled changes in %BF. Insulin, estradiol and FSH levels followed expected patterns relative to menarche. Leptin began rising closer to menarche than did insulin or the other sex hormones. Conclusion: We provide a visual presentation of hormonal and body composition changes occurring throughout the pubertal period in girls which may be useful in generating new hypotheses related to the timing of menarche. [source] Changes in Muscle Mass, Muscle Strength, and Power but Not Physical Function Are Related to Testosterone Dose in Healthy Older MenJOURNAL OF AMERICAN GERIATRICS SOCIETY, Issue 11 2008Thomas W. Storer PhD OBJECTIVES: To examine the effect of graded doses of testosterone on physical function and muscle performance in healthy, older men. DESIGN: Randomized, double-blind, placebo-controlled clinical trial. SETTING: General clinical research center. PARTICIPANTS: Community-dwelling healthy men aged 60 to 75 (N=44). INTERVENTION: Monthly treatment with a gonadotropin-releasing hormone agonist plus 25, 50, 125, or 300 mg/wk of intramuscular injections of testosterone enanthate for 20 weeks. MEASUREMENTS: Skeletal muscle mass (SMM) was estimated using dual-energy X-ray absorptiometry. Leg press strength was measured by one repetition maximum, leg power by Nottingham Leg Rig, and muscle fatigability by repetitions to failure in the leg press exercise. Stair climbing, 6-meter and 400-meter walking speed, and a timed-up-and-go (TUG) test were used to assess physical function. RESULTS: Significant testosterone dose- and concentration-dependent increases were observed in SMM (P<.001) and maximal strength (P=.001) but not muscle fatigability. Leg power also increased dose-dependently (P=.048). In contrast, changes in self-selected normal and fast walking speed over 6 or 400 meters, stair climbing power, and time for the TUG were not significantly related to testosterone dose, testosterone concentrations, or changes in muscle strength or power, or SMM. CONCLUSION: Testosterone administration was associated with dose-dependent increases in SMM, leg strength, and power but did not improve muscle fatigability or physical function. The observation that physical function scores did not improve linearly with strength suggests that these high-functioning older men were already in the asymptotic region of the curve describing the relationship between physical function and strength. [source] Exploratory Analysis of Cerebral Oxygen Reserves During Sleep Onset in Older and Younger AdultsJOURNAL OF AMERICAN GERIATRICS SOCIETY, Issue 5 2008Barbara W. Carlson RN OBJECTIVES: To explore differences in cerebral oxygen reserves during sleep in old and young adults. DESIGN: Descriptive cross-sectional study. SETTING: General clinical research center. PARTICIPANTS: Nine old (aged 65,84) and 10 young (aged 21,39) adults. MEASUREMENTS: Subjects were monitored during the first nightly sleep cycle using standard polysomnography, including measures of arterial oxyhemoglobin saturation (SaO2). Changes in regional cerebral oxyhemoglobin saturation (rcSO2) were used to estimate cerebral oxygen reserves. General linear models were used to test group differences in the change in SaO2 and rcSO2 during sleep. RESULTS: Older subjects had lower SaO2 than young subjects before sleep (baseline) (F(1,18)=5.1, P=.04) and during sleep (F(1,18)=10.7, P=.01). During sleep, half of the older subjects and none of the younger ones had SaO2 values below 95%. In addition, the older subjects had more periods of oxygen desaturation (drops in SaO2,4%) (chi-square=24.3, P=.01) and lower SaO2 levels during desaturation (F(1,18)=11.1, P<.01). Although baseline values were similar, rcSO2 decreased during sleep 2.1% in older subjects (F(1,8)=3.8, P=.05) but increased 2.1% during sleep in younger subjects (F(1,9)=4.6, P=.04). When the older subjects awakened from sleep, rcSO2, but not SaO2, returned to baseline; both returned to baseline in younger subjects. CONCLUSION: This exploratory analysis generated the hypothesis that lower SaO2, combined with declines in regional blood flow, contributes to decline in cerebral oxygen reserves during sleep in older subjects. Further study will assess the effects of factors (e.g., medical conditions, subclinical disorders, and sleep architecture) that might account for these differences. [source] | ||||||||||