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Cerebral blood flow characteristics following hemodialysis initiation in older adults: A prospective longitudinal pilot study using arterial spin labeling imaging.

September 29, 2020 - 7:20am
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Cerebral blood flow characteristics following hemodialysis initiation in older adults: A prospective longitudinal pilot study using arterial spin labeling imaging.

Neuroimage Clin. 2020 Sep 15;28:102434

Authors: Li X, Slinin YX, Zhang L, Dengel DR, Tupper D, Metzger GJ, Murray AM

Abstract
PURPOSE: To investigate cerebral blood flow (CBF) characteristics before and after hemodialysis initiation and their longitudinal associations with global cognitive function in older adults.
METHODS: A cohort of 17 older end-stage renal disease patients anticipating standard thrice-weekly hemodialysis and a group of 11 age- and sex-matched healthy control volunteers were recruited for brain perfusion imaging studies using arterial spin labeling. Hemodialysis patients participated in a prospective longitudinal study using brain magnetic resonance imaging and global cognitive assessment using the Modified Mini-Mental State Examination (3MS) at two time points: baseline, 2.9 ± 0.9 months before, and follow-up, 6.4 ± 2.4 months after hemodialysis initiation. Healthy controls were imaged once using the same protocol. CBF analyses were performed globally in grey and white matter and regionally in the hippocampus and orbitofrontal cortex. Covariate-adjusted linear mixed-effects models were used for statistical analyses (significance: p < 0.05; marginal significance: p < 0.1).
RESULTS: At baseline, global and regional CBF was significantly higher in hemodialysis patients than in healthy controls. However, after approximately 6 months of hemodialysis, CBF declined substantially in hemodialysis patients, and became comparable to those in healthy controls. Specifically, in the hemodialysis patients, CBF declined non-significantly globally for grey and white matter and significantly regionally in the hippocampus and orbitofrontal cortex. Marginally significant associations were observed between 3MS scores and regional CBF measurements in the hippocampus and orbitofrontal cortex at baseline and follow-up, and between longitudinal changes.
CONCLUSION: The significant decline in CBF after hemodialysis initiation and the observed association between longitudinal changes in regional CBF and 3MS scores suggest that decreased brain perfusion may contribute to the observed cognitive decline.

PMID: 32980601 [PubMed - as supplied by publisher]

Body fat percent assessment between electrical impedance myography and dual X-ray absorptiometry.

September 29, 2020 - 7:20am
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Body fat percent assessment between electrical impedance myography and dual X-ray absorptiometry.

Am J Hum Biol. 2020 03;32(2):e23330

Authors: Czeck MA, Raymond-Pope CJ, Prescott E, Bisch KL, Dengel DR

Abstract
OBJECTIVES: To compare total and regional body fat percent (BF%) measurements obtained using a handheld electrical impedance myography (EIM) device in comparison to BF% measured by dual X-ray absorptiometry (DXA).
METHODS: Sixty-nine male and female (33 males/36 females; age = 21.9 ± 2.0 years, body mass index = 24.5 ± 3.6 kg/m2 ) college-age individuals participated in this study. Each participant's total and regional (ie, upper arms, upper legs, trunk) BF% was estimated using EIM and DXA. Metallic markers were used to delineate regional boundaries for analysis, including upper arms (biceps/triceps), upper legs (quadriceps/hamstrings), and trunk (abdominal region/low back region). Paired t-tests assessed the accuracy of BF% values estimated from EIM in comparison to BF% measured by DXA.
RESULTS: Observations revealed EIM reported significantly lower BF% for upper left arm (P < .001), upper right arm (P < .001), upper right leg (P = .002), and trunk (P < .001) values. However, no significant differences were observed in total (P = .434) and upper left leg (P = .855) BF% between the two devices.
CONCLUSIONS: This study's observations suggest that, EIM may be an accurate field method for measuring total BF%, but not regional BF%.

PMID: 31566850 [PubMed - indexed for MEDLINE]

Positional Body Composition of Female Division I Collegiate Volleyball Players.

September 2, 2020 - 5:20am
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Positional Body Composition of Female Division I Collegiate Volleyball Players.

J Strength Cond Res. 2020 Aug 27;:

Authors: Bisch KL, Bosch TA, Carbuhn A, Stanforth PR, Oliver JM, Bach CW, Dengel DR

Abstract
Bisch, KL, Bosch, TA, Carbuhn, A, Stanforth, PR, Oliver, JM, Bach, CW, and Dengel, DR. Positional body composition of female division I collegiate volleyball players. J Strength Cond Res XX(X): 000-000, 2020-The primary study objective was to measure positional differences in total and regional body composition among female NCAA Division I collegiate volleyball players using dual X-ray absorptiometry (DXA). The secondary objective was to examine normative age curves for fat and lean mass (LM) variables. Ninety female volleyball players from 5 universities received a DXA scan. Athletes were categorized by position: middle blocker (MB = 31), outside hitter (OH = 32), setter (ST = 9), and Libero (LB = 18). Height, body mass, total and regional fat mass (FM), LM, bone mineral density (BMD), and abdominal visceral adipose tissue were measured by DXA. Body mass distribution ratios were calculated. The secondary age analysis included a subset of 153 DXA scans (n = 83, ages 18-21 years). Front row players (i.e., MB and OH) had significantly greater total and regional LM and BMD measures (p < 0.05, all), compared with non-front row players (i.e., LB and ST). Differences in total LM (p < 0.001) were significantly influenced by height. Front row players had consistently lower mass distribution ratios compared with non-front row players (p < 0.05, all). Lean mass index (LMI, p = 0.752) and FM index (FMI, p = 0.392) were not significantly different across ages. Back row players have greater relative upper body mass, whereas mass in front row players is more evenly distributed between the upper and lower body. Bone mineral density differences may be influenced by repeated impact of jumping during the attacking and blocking actions of front row players. Minimal changes in LMI and fluctuations in FMI can be expected across an athlete's career.

PMID: 32868679 [PubMed - as supplied by publisher]

Use of an aromatase inhibitor in children with congenital adrenal hyperplasia: Impact of anastrozole on bone mineral density and visceral adipose tissue.

August 25, 2020 - 5:20am
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Use of an aromatase inhibitor in children with congenital adrenal hyperplasia: Impact of anastrozole on bone mineral density and visceral adipose tissue.

Clin Endocrinol (Oxf). 2019 07;91(1):124-130

Authors: Halper A, Sanchez B, Hodges JS, Dengel DR, Petryk A, Sarafoglou K

Abstract
OBJECTIVE: Anastrozole, an aromatase inhibitor, has been used off-label in males with short stature to delay bone maturation. No studies have examined anastrozole's effect on bone mineral density (BMD) or body composition in children with congenital adrenal hyperplasia (CAH) due to 21-hydroxylase deficiency. Our objective was to evaluate anastrozole's effect on BMD and visceral adipose tissue (VAT) in children with CAH.
DESIGN: Total body BMD (TBMD) and L2-L4 BMD Z-scores were adjusted for height-for-age Z-scores (TBMDHAZ and L2-L4HAZ ). Hydrocortisone doses (mg/m2 /d) were averaged over the previous year. Comparison of treated vs not treated with anastrozole used linear regression adjusting for age, pubertal status, sex, CAH type, years on hydrocortisone, BMI Z-scores and bone age Z-scores.
PATIENTS: We compared 25 children with CAH treated with anastrozole (mean age 11.3 [SD 3.0] years, 56% males) vs 31 children with CAH not treated with anastrozole (13.5 [SD 4.6], 29%). Participants underwent a pubertal exam, bone age X-ray and dual X-ray absorptiometry (DXA) scan.
RESULTS: Average bone age Z-score of 4.3 SDs on beginning anastrozole decreased to 1.9 SDs at time of DXA exam (P = 0.0004) 5.2 (SD 2.2) years later. TBMD Z-scores (P = 0.51), L2-L4 BMD Z-scores (P = 0.66), VAT (P = 0.38), TBMDHAZ Z-scores (P = 0.66) and L2-L4HAZ Z-scores (P = 0.41) did not differ between children treated vs not treated with anastrozole.
CONCLUSION: Anastrozole significantly reduced bone age advancement in children with CAH and advanced bone age (>2SDs) without adverse effects on BMD or VAT. Longitudinal studies of anastrozole in children with CAH are needed to validate these findings.

PMID: 31070802 [PubMed - indexed for MEDLINE]

Relationship of Apolipoproteins with Subclinical Cardiovascular Risk in Youth.

August 17, 2020 - 5:21am

Relationship of Apolipoproteins with Subclinical Cardiovascular Risk in Youth.

J Pediatr. 2020 Aug 11;:

Authors: Czeck MA, Northrop EF, Evanoff NG, Dengel DR, Rudser KD, Kelly AS, Ryder JR

Abstract
OBJECTIVE: To examine the association of apolipoproteins with arterial stiffness and carotid artery structure in children and adolescents.
STUDY DESIGN: A total of 338 children and adolescents (178 females) with a mean age 13.0±2.8 years were examined. Apolipoproteins (AI, AII, B100, CII, CIII, and E) were measured via human apolipoprotein magnetic bead panel. Applanation tonometry determined pulse wave velocity (PWV) and ultrasound imaging measured carotid intima-media thickness (cIMT). Dual X-ray absorptiometry measured total body fat percent. Linear regression models were adjusted for Tanner Stage, sex, and race with further adjustments for BF%. Linear regression models also examined the interaction between Tanner Stage and apolipoproteins.
RESULTS: There was a significant positive association between PWV and apolipoproteins: AI (0.015m/sec/10μg/mL [0.005, 0.026], p=0.003), AII (0.036m/sec/10μg/mL [0.017, 0.056], P < .001), B100 (0.009m/sec/10μg/mL [0.002, 0.016], p=0.012), E (0.158m/sec/10μg/mL [0.080, 0.235], p<0.001), and CIII:CII ratio (0.033/μg/mL [0.014, 0.052], p<0.001). After adding BF% to the models, PWV remained positively associated with higher levels of apolipoproteins: AI, AII, B100, E, and CIII:CII ratio. Both with and without the adjustment for BF%, there were no significant associations between any apolipoprotein and cIMT. There were no significant interactions between Tanner Stage and apolipoproteins.
CONCLUSION: These findings suggest that higher levels of apolipoprotein AII, E, and CIII:CII ratio are associated with increased arterial stiffness in children and adolescents, both with and without adjusting for percent body fat. These specific apolipoproteins may be useful as biomarkers of cardiovascular risk.

PMID: 32795477 [PubMed - as supplied by publisher]

Assessing vascular characteristics of the fetal descending aorta: A feasibility study.

August 7, 2020 - 5:21am
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Assessing vascular characteristics of the fetal descending aorta: A feasibility study.

J Clin Ultrasound. 2020 May;48(4):211-215

Authors: Evanoff NG, Dengel DR, Narasimhan S

Abstract
Research describing fetal arterial structure and function is lacking within the literature. This study's purpose was to measure intima-media thickness (IMT), compliance and distensibility of 24- to 25-week fetuses' abdominal aortas using conventional ultrasonography from 16 diabetic (DM) and 25 non-diabetic mothers (NDM). We found no significant differences in fetal abdominal aorta IMT (P = .68), diameter distensibility (P = .22), or cross-sectional distensibility (P = .23). However, both fetal abdominal aortic diameter compliance (P = .03) and cross-sectional compliance (P = .005) were greater in DM than in NDM (P = .005). This study demonstrates that it is possible and potentially useful to measure fetal abdominal aorta biometrics and biomechanical characteristics.

PMID: 32175628 [PubMed - indexed for MEDLINE]

The Effect of Atorvastatin on Vascular Function and Structure in Young Adult Survivors of Childhood Cancer: A Randomized, Placebo-Controlled Pilot Clinical Trial.

July 22, 2020 - 5:19am
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The Effect of Atorvastatin on Vascular Function and Structure in Young Adult Survivors of Childhood Cancer: A Randomized, Placebo-Controlled Pilot Clinical Trial.

J Adolesc Young Adult Oncol. 2019 08;8(4):442-450

Authors: Marlatt KL, Steinberger J, Rudser KD, Dengel DR, Sadak KT, Lee JL, Blaes AH, Duprez DA, Perkins JL, Ross JA, Kelly AS

Abstract
Purpose: Many adult survivors of childhood cancer are at high-risk of developing cardiovascular disease. Cancer therapy may cause damage to the vascular endothelium, thereby initiating atherosclerosis. Atorvastatin has been shown to improve endothelial function independent of reducing cholesterol, as well as reduce/slow arterial stiffness and thickening, yet has never been studied in childhood cancer survivors (CCS). Methods: Twenty-seven young adult (age 26.8 ± 6.2 years) survivors of childhood acute lymphoblastic leukemia or Non-Hodgkin's lymphoma were randomly assigned (1:1) 40 mg/day of atorvastatin or placebo for 6 months. Brachial artery flow-mediated dilation (FMD), small artery reactive hyperemia index (RHI), arterial stiffness, and carotid artery elasticity/thickness were assessed. Results: Fifteen participants completed the trial. No significant treatment effect for any vascular outcomes was observed at 6 months; however, a significant decrease in peak FMD (-3.0 [95% confidence interval [CI]: -5.3, -0.7]) and a trending significant decrease in RHI (-0.3 [95% CI: -0.62, 0.01]) was observed in the placebo group, resulting in a trend toward a treatment effects (p < 0.10). No effect on arterial stiffness, carotid arterial elasticity, or thickness was observed. Conclusion: Six months of atorvastatin treatment did not improve endothelial function or arterial stiffness in young adult CCS. While a trend toward an improvement in endothelial function was present, findings should be interpreted with caution owing to the small number of evaluable participants and subsequent lack of sufficient power. Further research in a larger sample size is needed to fully elucidate the effects of atorvastatin on vascular function. Trial registered at clinicaltrials.gov as NCT01733953.

PMID: 28853979 [PubMed - indexed for MEDLINE]

Reaching the Tipping Point: Identification of Thresholds at which Visceral Adipose Tissue May Steeply Increase in Youth.

July 14, 2020 - 5:20am
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Reaching the Tipping Point: Identification of Thresholds at which Visceral Adipose Tissue May Steeply Increase in Youth.

Obesity (Silver Spring). 2020 01;28(1):139-145

Authors: Kelly AS, Kaizer AM, Bosch TA, Rudser KD, Ryder JR, Gross AC, Chow LS, Fox CK, Dengel DR

Abstract
OBJECTIVE: This study aimed to determine whether children and adolescents demonstrate, similarly to adults, a threshold of total percent body fat (%BF) above which the slope of visceral adipose tissue (VAT) rises.
METHODS: This cross-sectional study included 557 youth, aged 8 to 18 years, with a wide range of BMI values. Dual-energy x-ray absorptiometry was used to determine body composition (including VAT), and fasting blood was collected for measurement of lipids, glucose, insulin, and biomarkers. Segmented linear regression analysis identified the threshold for %BF unadjusted and adjusted for Tanner stage. Linear regression with robust variance estimation compared associations of risk factors and thresholds.
RESULTS: Thresholds of %BF were identified by sex (males = 33%, females = 38%), age (< 12 years = 34%; ≥ 12 years = 30%), and race (White/non-Hispanic = 31%; all other races/Hispanic = 38%) above which the slope of VAT was significantly steeper (all P < 0 .001). The percentage of total body fat stored as VAT was higher above versus below these thresholds (all P < 0.001). Above threshold, but not below it, VAT was associated with triglycerides/high-density lipoprotein ratio, insulin, adiponectin, and blood pressure.
CONCLUSIONS: The thresholds should be confirmed in longitudinal studies, and they may be useful in identifying youth at increased cardiometabolic risk in need of close clinical monitoring and/or intensive intervention to reduce excess adiposity.

PMID: 31773904 [PubMed - indexed for MEDLINE]

Body Composition of National Collegiate Athletic Association (NCAA) Division I Female Soccer Athletes through Competitive Seasons.

July 11, 2020 - 5:24am

Body Composition of National Collegiate Athletic Association (NCAA) Division I Female Soccer Athletes through Competitive Seasons.

Int J Sports Med. 2020 Jul 10;:

Authors: Roelofs E, Bockin A, Bosch T, Oliver J, Bach CW, Carbuhn A, Stanforth PR, Dengel DR

Abstract
The purpose of this study was to examine body composition of National Collegiate Athletic Association Division I female soccer players by position and season. One hundred seventy-five female athletes were categorized by positions of forward (n=47), midfielder (n=51), defender (n=57), and goalkeeper (n=20). A dual X-ray absorptiometry scan assessed percent body fat, total lean mass, total fat mass, arm and leg lean mass and fat mass, and visceral adipose tissue. Goalkeepers had significantly higher total, arm, and leg lean mass and fat mass compared to all other positions (p<0.05). For seasonal changes, body fat percentage was significantly higher in winter off-season (26.7%) compared to summer off-season (25.7%) and pre-season (25.8%; p<0.01) for all positions. Total and leg lean mass was significantly lower in winter off-season compared to all other seasons, and total lean mass was significantly higher in summer off-season than pre-season (p<0.01). Overall, goalkeepers were significantly different than all other positions. Body fat percentage increased and lean mass decreased in winter off-season indicating potential undesired changes in training and/or nutrition over the break whereas lean mass was the highest in summer off-season potentially reflecting the emphasis on resistance training and increased volume of training.

PMID: 32650343 [PubMed - as supplied by publisher]

DXA-Determined Regional Adiposity Relates to Insulin Resistance in a Young Adult Population with Overweight andObesity.

June 26, 2020 - 5:21am
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DXA-Determined Regional Adiposity Relates to Insulin Resistance in a Young Adult Population with Overweight andObesity.

J Clin Densitom. 2019 Apr - Jun;22(2):287-292

Authors: Bantle AE, Bosch TA, Dengel DR, Wang Q, Mashek DG, Chow LS

Abstract
Obesity is a well-established risk factor for insulin resistance and type 2 diabetes mellitus, and body fat distribution has important implications for this metabolic risk. In this cross-sectional study, we used dual X-ray absorptiometry body composition data from 123 young adult participants with overweight or obesity, and correlatedwith 2 indices of insulin resistance calculated from oral glucose tolerance tests. Participants were 70% women, with mean (standard error) age 30.1 (0.6) yr, body mass index (BMI) 34.0 (0.6) kg/m2, homeostatic model assessment of insulin resistance (HOMA-IR) of 2.1 (0.2), and Matsuda insulin sensitivity index (Matsuda ISI) of 5.8 (0.4). In women, the strongest correlations were observed with the android-to-gynoid ratio (r = 0.52, p < 0.001 for HOMA-IR; r = -0.46, p < 0.001 for Matsuda ISI), and these correlations remained significant after adjustment for BMI. For men, the strongest correlations were with android fat mass (r = 0.40, p = 0.01 for HOMA-IR; r = -0.37, p = 0.02 for Matsuda ISI). Visceral adipose tissue was correlated with HOMA-IR and Matsuda ISI in women, and only with Matsuda ISI in men. BMI correlated with HOMA-IR and with Matsuda ISI in both women and men. Regional adiposity determined by dual X-ray absorptiometry correlates with indices of insulin resistance in sedentary young adults with overweight and obesity.

PMID: 30064815 [PubMed - indexed for MEDLINE]