Eccentric muscle challenge shows osteopontin polymorphism modulation of muscle damage.

A promoter polymorphism of the osteopontin (OPN) gene (rs28357094) has been associated with multiple inflammatory states, severity of Duchenne muscular dystrophy (DMD) and muscle size in healthy young adults. We sought to define the mechanism of action of the polymorphism, using allele-specific in vitro reporter assays in muscle cells, and a genotype-stratified intervention in healthy controls. In vitro reporter constructs showed the G allele to respond to estrogen treatment, whereas the T allele showed no transcriptional response. Young adult volunteers (n = 187) were enrolled into a baseline study, and subjects with specific rs28357094 genotypes enrolled into an eccentric muscle challenge intervention [n = 3 TT; n = 3 GG/GT (dominant inheritance model)]. Female volunteers carrying the G allele showed significantly greater inflammation and increased muscle volume change as determined by magnetic resonance imaging T1- and T2-weighted images after eccentric challenge, as well as greater decrement in biceps muscle force. Our data suggest a model where the G allele enables enhanced activities of upstream enhancer elements due to loss of Sp1 binding at the polymorphic site. This results in significantly greater expression of the pro-inflammatory OPN cytokine during tissue remodeling in response to challenge in G allele carriers, promoting muscle hypertrophy in normal females, but increased damage in DMD patients.

Exaggerated vasopressor response to exercise and cerebral blood flow velocity.

We studied 10 young adults, normotensive at rest, comprising a control group (n = 5) with normal blood pressure responsiveness to exercise and an experimental group exhibiting greater percentage of body fat and body mass index (BMI) than the controls, with exaggerated blood pressure (vasopressor) responsiveness to exercise (EEBPR) (n = 5). Lower absolute and varying oxygen consumption/body weight normalized units of middle cerebral arterial blood flow velocity (MCAV) were found during exercise in the experimental group (P < .01). These findings support the hypothesis that the combination of EEBPR and high BMI is associated with low MCAV that may put such individuals at risk for cerebral hypoperfusion and cognitive deficits.

Mood Responses to Passive and Active Motion Leg Cycling Exercise in Healthy Sedentary Young Adults.

Previous studies suggest that passive motion exercise (PME) may be useful for overcoming exercise limitations associated with a sedentary lifestyle, orthopedic disorders, and various other debilitating conditions. Negative mood response is one of the factors that limit a person's ability to exercise. Therefore, this study tests the hypothesis that the mood response associated with PME is not different than the mood response associated with active motion exercise (AME). Eight women and seven men participated in the study and were administrated the Profile of Mood States (POMS) during modes of PME and AME in a randomized order. Outcome of the POMS consisted of the total mood disturbance score [(feelings of tension + depression + fatigue + anger + confusion) - vigor]. ANOVA was used to determine significance of differences in total mood disturbance, oxygen uptake (V.O2), and middle cerebral blood flow velocity (MCAv) at baseline and immediately after 30-minute conditions of PME and AME. Postexercise total mood disturbance score was significantly decreased for both conditions (PME baseline 29.2 ± 5.2 vs. postexercise 16.4 ± 6.8, P < 0.05) and AME baseline 22.4 ± 4.4 vs. postexercise 13.1 ± 5.2, P < 0.05). These senses of changes in feelings were associated with significant physiological increases in V.O2 and MCAv during both PME and AME (P < 0.05). These results demonstrate that physiological and mood responses to passive and active motion cycling exercise are not different. Future studies should determine whether passive motion cycling exercise is a useful preventive medicine strategy for overcoming various disease-related exercise limitations and counteracting the adverse effects of sedentary lifestyles.

Associations of Alpha and Beta Interhemispheric EEG Coherences with Indices of Attentional Control and Academic Performance.

Introduction. Heretofore, research on optimizing academic performance has suffered from an inability to translate what is known about an individual's learning behaviors to how effectively they are able to use the critical nodes and hubs in their cerebral cortex for learning. A previous study from our laboratory suggests that lower theta-beta ratios (TBRs) measured by EEG may be associated with higher academic performance in a medical school curriculum. METHODS: In this study, we tested the hypothesis that TBR and academic performance may be correlated with EEG coherence, a measure of brain connectivity. We analyzed the interhemispheric coherences of the subjects involved in our prior study. TBR and coherence measurements were made at 19 scalp electrode recording sites and 171 electrode combinations with eyes open and closed (EO, EC). Control data were acquired during a session of acclimation to the research protocol 3 d before an initial examination in anatomy-physiology (control exam) and were repeated five weeks later, 3 d before a second exam covering different anatomy-physiology topics (comparison exam). RESULTS: Between the control and comparison exams, beta coherences increased significantly at the frontal pole, frontal, parietal, midtemporal, posterior temporal, and occipital recording sites under the EO condition and at the inferior frontal, central, midtemporal, and posterior temporal sites under the EC condition. Alpha coherences increased significantly at the same sites and under the same EO/EC conditions as found for the beta coherences. The beta coherences were negatively correlated with the TBR and were positively correlated with the comparison exam score at the midfrontal electrode site (F3-F4) but only under the EO condition. Beta and alpha coherences at the midfrontal, inferior frontal midtemporal, posterior temporal, and occipital sites were also negatively correlated with the average TBR under the EO condition. CONCLUSIONS: Lower TBR, an indicator of attentional control, was associated with higher alpha and beta interhemispheric coherences measured with eyes open at sites overlying the frontal, temporal, and occipital cortices. Changes in EEG coherences and TBRs might be useful as neurophysiological measures of neuroplasticity and the efficacy of strategies for preventing academic underachievement and treatments for improving academic performance.

Association of Endothelial Function with Parental Hypertension in Normotensive-Obese African-American Women: A Pilot Study.

Obese African-American (AA) women are at high risk of hypertension (HT) and cardiovascular disease (CVD). Flow-mediated dilation (FMD) and arterial augmentation index (AI) are measures of endothelial function and arterial stiffness. Whether endothelial function and arterial stiffness predict risk of HT or CVD in obese African-American women with, versus without, parental histories of HT and whether aerobic exercise is an effective countermeasure remain unclear. The capacity for FMD is partly heritable. Therefore, we tested the hypotheses that less FMD and greater AI may be found in normotensive-obese, young-adult (18-26 year-old) AA women with hypertensive parents (n=10) than in a matched control group with normotensive parents (n=10) and that a single bout of aerobic exercise improves both endothelial function and arterial stiffness, with less improvement in the women with hypertensive parents. We studied each subject while at rest, 20 min before and 20 min after, 30 min of aerobic exercise. The exercise-induced changes and parental hypertension-related differences in AI were not significant. The exercise increased FMD in both of the groups with no significant difference in magnitude between the women with hypertensive and normotensive parents. FMD was significantly less in the women with hypertensive parents than in the women with normotensive parents after, but not before, the exercise (mean ±95% confidence interval of 11.3 ± 4.9% vs. 15.6 ± 4.9%, P=0.05). These findings suggest that a 30-min bout of aerobic exercise may improve FMD and unmask endothelial dysfunction in normotensive-obese, young-adult AA women with parental histories of HT. Future studies should determine whether regular aerobic exercise protects obese AA women from the endothelial dysfunction associated with diabetes and prevents CVD in this high-risk population.

qEEG Measures of Attentional and Memory Network Functions in Medical Students: Novel Targets for Pharmacopuncture to Improve Cognition and Academic Performance.

OBJECTIVES: Attentional and memory functions are important aspects of neural plasticity that, theoretically, should be amenable to pharmacopuncture treatments. A previous study from our laboratory suggested that quantitative electroencephalographic (qEEG) measurements of theta/beta ratio (TBR), an index of attentional control, may be indicative of academic performance in a first-semester medical school course. The present study expands our prior report by extracting and analyzing data on frontal theta and beta asymmetries. We test the hypothesis that the amount of frontal theta and beta asymmetries (fTA, fBA), are correlated with TBR and academic performance, thereby providing novel targets for pharmacopuncture treatments to improve cognitive performance. METHODS: Ten healthy male volunteers were subjected to 5-10 min of qEEG measurements under eyes-closed conditions. The qEEG measurements were performed 3 days before each of first two block examinations in anatomy-physiology, separated by five weeks. Amplitudes of the theta and beta waveforms, expressed in µV, were used to compute TBR, fTA and fBA. Significance of changes in theta and beta EEG wave amplitude was assessed by ANOVA with post-hoc t-testing. Correlations between TBR, fTA, fBA and the raw examination scores were evaluated by Pearson's product-moment coefficients and linear regression analysis. RESULTS: fTA and fBA were found to be negatively correlated with TBR (P<0.03, P<0.05, respectively) and were positively correlated with the second examination score (P<0.03, P=0.1, respectively). CONCLUSION: Smaller fTA and fBA were associated with lower academic performance in the second of two first-semester medical school anatomy-physiology block examination. Future studies should determine whether these qEEG metrics are useful for monitoring changes associated with the brain's cognitive adaptations to academic challenges, for predicting academic performance and for targeting phamacopuncture treatments to improve cognitive performance.

Acute exercise and postexercise blood pressure in African American women.

BACKGROUND: Limited data suggest that physical activity increases postexercise blood pressure in African-American women. The purpose of this study was to evaluate the postexercise blood pressure response to acute exercise in normotensive young adult African-American women. METHODS: Eight healthy women (age 22.5+/-.9 years) performed a cycle ergometer bout of 30 minutes at 60% of peak ventilatory oxygen uptake (VO2 peak). Control arterial blood pressure, heart rate, lower leg blood flow, cardiac output, spectral analysis of blood pressure, heart rate variability, and baroreceptor sensitivity were measured for 5 minutes before exercise and were compared to postexercise measurements performed at rest intervals of 15-20, 35-40 and 55-60 minutes after exercise. RESULTS: Exercise performed at 60% VO2 peak produced an arterial pressure of 172+/-10/ 70.1+/-4.0 mm Hg. Postexercise recovery values were not significantly different than the baseline control values. CONCLUSION: These results do not support the hypothesis that acute physical activity exerts an adverse effect on postexercise blood pressure in African American women.

Restricted Blood Flow Exercise in Sedentary, Overweight African-American Females May Increase Muscle Strength and Decrease Endothelial Function and Vascular Autoregulation.

OBJECTIVES: Exercise with partially restricted blood flow is a low-load, low-intensity resistance training regimen which may have the potential to increase muscle strength in the obese, elderly and frail who are unable to do high-load training. Restricted blood flow exercise has also been shown to affect blood vessel function variably and can, therefore, contribute to blood vessel dysfunction. This pilot study tests the hypothesis that unilateral resistance training of the leg extensors with partially restricted blood flow increases muscle strength and decreases vascular autoregulation. METHODS: The subjects were nine normotensive, overweight, young adult African-Americans with low cardiorespiratory fitness who underwent unilateral training of the quadriceps' femoris muscles with partially restricted blood flow at 30% of the 1-repetition maximum (1-RM) load for 3 weeks. The 1-RM load and post-occlusion blood flow to the lower leg (calf) were measured during reactive hyperemia. RESULTS: The 1-RM load increased in the trained legs from 77 ± 3 to 84 ± 4 kg (P < 0.05) in the absence of a significant effect on the 1-RM load in the contralateral untrained legs (P > 0.1). Post-occlusion blood flow decreased significantly in the trained legs from 19 ± 2 to 13 ± 2 mL· min-1· dL-1 (P < 0.05) and marginally in the contralateral untrained legs from 18 ± 2 to 16 ± 1 mL· min-1· dL-1 (P = 0.09). Changes in post-occlusion blood flow to the skin overlying the trained and the contralateral untrained muscles were not significant. CONCLUSION: These results demonstrate that restricted blood flow exercise, which results in significant gains in muscle strength, may produce decrements in endothelial dysfunction and vascular autoregulation. Future studies should determine whether pharmacopuncture plays a role in treatments for such blood vessel dysfunction.

Relationship Between Aerobic Fitness, the Serum IGF-1 Profiles of Healthy Young Adult African American Males, and Growth of Prostate Cancer Cells.

The growth of prostate tumors is mediated by the bioavailability of androgens and insulin-like growth factors. This study tested the hypothesis that healthy young adult African American men exhibiting low aerobic capacity (fitness) have serum insulin-like growth Factor-1 (IGF-1) and testosterone levels that promote growth of prostate cancer cells. A cross-sectional data research design was used to study groups of 18- to 26-year-old healthy men exhibiting low and moderate aerobic fitness, based on their peak oxygen consumption (VO2peak). The individual serum levels of IGF-1, IGF-1 binding protein-3 (IGFBP-3), and testosterone were measured. In vitro growth of androgen-dependent LNCaP prostate tumor cells was measured after incubation in culture medium fortified with each subject's serum. Aerobic capacity was significantly greater in the moderate-fitness group than in the low-fitness group without an intergroup difference in body mass index. The serum IGF-1 concentration was significantly higher in the low-fitness group in the absence of an intergroup difference in serum testosterone. The serum IGFBP-3 concentration was significantly lower in the low-fitness group. Prostate tumor cell growth was significantly greater in the cultures incubated in media containing the sera of the low-fitness group than in the sera of the moderate-fitness group. These findings suggest that moderate aerobic fitness in young adults may decrease the circulating levels of free IGF-1 and lower the potential to support growth of prostate cancer cells.

APOEε4 impacts up-regulation of brain-derived neurotrophic factor after a six-month stretch and aerobic exercise intervention in mild cognitively impaired elderly African Americans: A pilot study.

Possession of the Apolipoprotein E (APOE) gene ε4 allele is the most prevalent genetic risk factor for late onset Alzheimer's disease (AD). Recent evidence suggests that APOE genotype differentially affects the expression of brain-derived neurotrophic factor (BDNF). Notably, aerobic exercise-induced upregulation of BDNF is well documented; and exercise has been shown to improve cognitive function. As BDNF is known for its role in neuroplasticity and survival, its upregulation is a proposed mechanism for the neuroprotective effects of physical exercise. In this pilot study designed to analyze exercise-induced BDNF upregulation in an understudied population, we examined the effects of APOEε4 (ε4) carrier status on changes in BDNF expression after a standardized exercise program. African Americans, age 55years and older, diagnosed with mild cognitive impairment participated in a six-month, supervised program of either stretch (control treatment) or aerobic (experimental treatment) exercise. An exercise-induced increase in VO2Max was detected only in male participants. BDNF levels in serum were measured using ELISA. Age, screening MMSE scores and baseline measures of BMI, VO2Max, and BDNF did not differ between ε4 carriers and non-ε4 carriers. A significant association between ε4 status and serum BDNF levels was detected. Non-ε4 carriers showed a significant increase in BDNF levels at the 6month time point while ε4 carriers did not. We believe we have identified a relationship between the ε4 allele and BDNF response to physiologic adaptation which likely impacts the extent of neuroprotective benefit gained from engagement in physical exercise. Replication of our results with inclusion of diverse racial cohorts, and a no-exercise control group will be necessary to determine the scope of this association in the general population.

Differentiation of Overweight from Normal Weight Young Adults by Postprandial Heart Rate Variability and Systolic Blood Pressure.

INTRODUCTION: Obesity and cardiovascular disease are inextricably linked and the health community's response to the current epidemic of adolescent obesity may be improved by the ability to target adolescents at highest risk for developing cardiovascular disease in the future. Overweight manifests early as autonomic dysregulation and current methods do not permit differentiation of overweight adolescents or young adults at highest risk for developing cardiovascular disease. AIM: This study was designed to test the hypothesis that scaling exponents motivated by nonlinear fractal analyses of Heart Rate Variability (HRV) differentiate overweight, otherwise healthy adolescent/young adult subjects at risk for developing prehypertension, the primary forerunner of cardiovascular disease. MATERIALS AND METHODS: The subjects were 18-20year old males with Body Mass Index (BMI) 20.1-42.5kg/m(2). Electrocardiographic inter-beat (RR) intervals were measured during 3h periods of bed rest after overnight fasting and ingestion of 900Cal high-carbohydrate and high-fat test beverages on separate days. Detrended Fluctuation Analysis (DFA), k-means cluster and ANOVA analyses of scaling coefficients α, α(1), and α(2), showed dependencies on hourly measurements of systolic blood pressure and on premeasured BMI. RESULTS: It was observed that α value increased during the caloric challenge, appears to represent metabolically-induced changes in HRV across the participants. An ancillary analysis was performed to determine the dependency on BMI without BMI as a parameter. Cluster analysis of the high-carbohydrate test beverage treatment and the high-fat treatment produced grouping with very little overlap. ANOVA on both clusters demonstrated significance at p<0.001. We were able to demonstrate increased sympathetic modulation of our study group during ingestion and metabolism of isocaloric high-carbohydrate and high-fat test beverages. CONCLUSION: These findings demonstrate significantly different clustering of α, α1, and α2 and Systolic Blood Pressure (SBP) with respect to normal, overweight and obese BMI.

Effects of Swimming Exercise on Learning and Memory in the Kainate-Lesion Model of Temporal Lobe Epilepsy.

INTRODUCTION: An aerobic exercise (Ex) augments neurogenesis and may ameliorate learning and memory deficits in the rat Kainic Acid (KA) model of temporal lobe epilepsy in the short-term but whether it reverses learning and memory deficits after a substantial period of delay remains unclear. AIM: This study tests the hypothesis that aerobic Ex attenuates the learning and memory deficits associated with kainate seizures in the long-term. MATERIALS AND METHODS: A total of 60 rats were subjected to chemical lesioning using KA and to an Ex intervention consisting of a 30 days period of daily swimming for 15 min, immediately after KA lesioning (immediate exposure) or after a 60 days period of normal activity (delayed exposure). We evaluated spatial learning on a T-maze test, expressed as percentage of correct responses. We evaluated memory on a passive-avoidance test, expressed as time spent in a compartment in which the rats were previously exposed to an aversive stimulus. RESULTS: Ex increases the percentage of correct responses, percentage bias, and number of alternations, associated with the T-maze testing for the normal control, sham-operated control and kainate-lesioned animals after both immediate and delayed exposures to Ex. Ex decreased the time exposed to the aversive stimulus in the smaller compartment of the two-compartment passive-avoidance test, also for the normal control, sham-operated control and kainate-lesioned animals after both immediate and delayed exposures to Ex. CONCLUSION: These findings suggest that, after temporal lobe epileptic seizures in rats, swimming exercise may attenuate the learning and memory deficits, even if the exercise treatment is delayed.

Nonlinear Conte-Zbilut-Federici (CZF) Method of Computing LF/HF Ratio: A More Reliable Index of Changes in Heart Rate Variability.

OBJECTIVES: Acupuncture treatments are safe and effective for a wide variety of diseases involving autonomic dysregulation. Heart rate variability (HRV) is a noninvasive method for assessing sympathovagal balance. The low frequency/high frequency (LF/HF) spectral power ratio is an index of sympathovagal influence on heart rate and of cardiovascular health. This study tests the hypothesis that from rest to 30% to 50% of peak oxygen consumption, the nonlinear Conte-Zbilut-Federici (CZF) method of computing the LF/HF ratio is a more reliable index of changes in the HRV than linear methods are. METHODS: The subjects of this study were 10 healthy young adults. Electrocardiogram RR intervals were measured during 6-minute periods of rest and aerobic exercise on a cycle ergometer at 30% and 50% of peak oxygen consumption (VO2peak). RESULTS: The frequency domain CZF computations of the LF/HF ratio and the time domain computations of the standard deviation of normal-to-normal intervals (SDNN) decreased sequentially from rest to 30% VO2peak (P < 0.001) to 50% VO2peak (P < 0.05). The SDNN and the CZF computations of the LF/HF ratio were positively correlated (Pearson's r = 0.75, P < 0.001). fast Fourier transform (FFT), autoregressive (AR) and Lomb periodogram computations of the LF/HF ratio increased only from rest to 50% VO2peak. CONCLUSION: Computations of the LF/HF ratio by using the nonlinear CZF method appear to be more sensitive to changes in physical activity than computations of the LF/HF ratio by using linear methods. Future studies should determine whether the CZF computation of the LF/HF ratio improves evaluations of pharmacopuncture and other treatment modalities.

Effects of a Dietary Beetroot Juice Treatment on Systemic and Cerebral Haemodynamics- A Pilot Study.

INTRODUCTION: Beetroot Juice (BJ) contains dietary nitrates that increase the blood Nitric Oxide (NO) level, decrease Blood Pressure (BP), increase athletic performance and improve cognitive functions but the mechanism remains unclear. Ultrasonographic measurement of middle cerebral artery blood flow velocity with computation of Cerebral Augmentation Index (CAIx) is a measure of the reflected flow signal, modulated by changes in cerebrovascular resistance and compliance. AIM: This pilot study tests the hypothesis that ingestion of an amount of BJ sufficient to raise the blood NO level two-to three-fold, decreases Transcranial Doppler (TCD) measured CAIx. MATERIALS AND METHODS: Ten healthy young-adult African-American women were studied at two levels of submaximal exercise, 40% and 80% of their predetermined peak oxygen consumptions. The subjects ingested nitrate-free orange juice (OJ, control) and an isocaloric BJ beverage (1.5 mg/mL nitrate, 220 Cal), on different days, 1-2 weeks apart. RESULTS: The BJ treatment increased blood NO and decreased systolic BP at rest and at the two levels of exercise. The BJ treatment decreased CAIx only at the two levels of exercise (from 79 ± 2% to 62 ± 2% and from 80 ± 2% to 60 ± 3%, p<0.05). Exercise increased TCD-measured resistance and pulsatility indices (RIx, PIx) without changing AIx. The BJ treatment had no effect on RIx and PIx. CONCLUSION: These findings suggest that decreased CAIx associated with aerobic exercise reflects the change in cerebral haemodynamics resulting from dietary nitrate supplementation. Future studies should determine whether the BJ-induced decrement in CAIx is correlated with an improvement in brain function.

Cardiovascular Responses to an Isometric Handgrip Exercise in Females with Prehypertension.

BACKGROUND: Hypertensive individuals are known to exhibit greater increases in blood pressure during an isometric handgrip exercise (IHE) than their normotensive counterparts. AIM: This study tests the hypothesis that, compared to normotensive individuals, prehypertensive individuals exhibit an exaggerated response to IHE. MATERIALS AND METHODS: In this study, the effects of IHE were compared in matched prehypertensive vs. normotensive healthy African-American females. Six healthy young adult African-American female university students were screened in a physician's office for blood pressure in the range of prehypertension, systolic blood pressure (SBP) 120-139 mmHg and diastolic blood pressure (DBP) 80-89 mmHg. Six young adult African-American women were also recruited to serve as a healthy normotensive control group with SBP ≤119 mmHg and DBP ≤79 mmHg. Cardiovascular fitness was determined by peak oxygen uptake (VO2 peak) measured during a progressive exercise test. RESULTS: During the handgrip exercise, the prehypertensive group exhibited greater increases in SBP (from 139 ± 6 to 205 ± 11 mmHg, +48%) than the controls (from 132 ± 3 to 145 ± 3 mmHg, +10%); intergroup difference P < 0.001. The prehypertensive group also exhibited greater increases in DBP (from 77 ± 2 to 112 ± 5 mmHg, +46%) compared to the controls (from 72 ± 3 to 78 ± 4 mmHg, +8%); intergroup difference P < 0.001. The increase in systemic vascular resistance was also greater in the prehypertensive group (from 1713 ± 91 to 2807 ± 370 dyne.s.cm(-5), +64%) than in the controls (from 1668 ± 80 to 1812 ± 169 dyne.s.cm(-5), +9%); intergroup difference P < 0.05. CONCLUSION: These results suggest that blood pressure measurements performed during IHE may be a useful screening tool in evaluating prehypertensive individuals for antihypertensive treatments.

Ethnic and age-related fat free mass loss in older Americans: the Third National Health and Nutrition Examination Survey (NHANES III).

BACKGROUND: Although age-related loss of fat free mass (FFM) is well known, there is paucity of data on national estimates, and on the differential influence of ethnicity on the decline in FFM with increasing age. We determined whether age-related loss in FFM and fat free mass index (FFMI) vary by gender and or ethnicity, using representative data from the Third National Health and Nutrition Examination Survey (NHANES III). METHODS: Analyses were limited to 5,803 non-institutionalized, non-Hispanic Whites and African Americans (Blacks) over the age of 40 years. Body density was calculated from the sum of 3-skinfolds, and percent body fat estimated from body density. FFM was estimated by subtracting body fat from body weight, while FFMI was defined as FFM (kilograms) divided by the square of body height (meter2). RESULTS: Overall FFM and FFMI were significantly higher in black women than white women (P = 0.001; P = 0.001 respectively), but similar in black men compared to white men. Age-related decline in FFM reached significance level earlier in black men (at age 65-69) than white men (at age 70-74), and in black women (at age 70-74) than white women (at age 75-79). Similar decline in FFMI was noted in men and in women. In multivariate analyses, FFM significantly associated with ethnicity (p = 0.012) and with age (p < 0.001) in women, but only with age (p < 0.001) in men. In men and in women, FFMI significantly associated with ethnicity (p < 0.001; p = 0.003 respectively) and with age (p < 0.001; p = 0.004 respectively). CONCLUSION: Age-related loss and decline in FFM and FFMI in older Americans is higher for black men and women, than for white men and women. The development of focused population-based preventive strategies is likely to improve functional independence in the aged.

Attenuation of exaggerated exercise blood pressure response in African-American women by regular aerobic physical activity.

INTRODUCTION: A hyperreactive blood pressure response to exercise is a predictor of developing hypertension. The present study determined the influence of physical activity on an exaggerated exercise blood pressure response (EEBPR) in normotensive African-American women. METHODS: We screened 36 women 18-26 years of age for EEBPR defined as a > or = 50 mm Hg difference in systolic blood pressure at rest and during exercise at 50% peak oxygen uptake (VO2peak). Seven subjects demonstrated an EEBPR and participated in the study. Study participants trained for eight weeks on a bicycle ergometer at a work intensity of 70% VO2peak. Blood pressure, heart rate, cardiac output (CO), stroke volume (SV), and total peripheral vascular resistance (TPR) were determined at baseline and during submaximal exercise at power outputs of 30 W and 50% VO2peak. Subjects served as their own controls, and data were evaluated by using a paired t test at P<.05. RESULTS: Effectiveness of the intervention was shown by a significantly greater VO2peak associated with significant decrements in systolic and mean arterial pressures at power outputs of 30 W and 50% VO2peak. A significant decrement in heart rate was observed during exercise at 30 W. Significant increments in CO and SV and decrement in TPR were found during exercise at 50% VO2peak. CONCLUSION: The reduction in TPR associated with regular aerobic physical activity may attenuate the EEBPR and decrease the risk for hypertension in normotensive, young-adult, African-American women.

A standardized randomized 6-month aerobic exercise-training down-regulated pro-inflammatory genes, but up-regulated anti-inflammatory, neuron survival and axon growth-related genes.

There is considerable support for the view that aerobic exercise may confer cognitive benefits to mild cognitively impaired elderly persons. However, the biological mechanisms mediating these effects are not entirely clear. As a preliminary step towards informing this gap in knowledge, we enrolled older adults confirmed to have mild cognitive impairment (MCI) in a 6-month exercise program. Male and female subjects were randomized into a 6-month program of either aerobic or stretch (control) exercise. Data collected from the first 10 completers, aerobic exercise (n=5) or stretch (control) exercise (n=5), were used to determine intervention-induced changes in the global gene expression profiles of the aerobic and stretch groups. Using microarray, we identified genes with altered expression (relative to baseline values) in response to the 6-month exercise intervention. Genes whose expression were altered by at least two-fold, and met the p-value cutoff of 0.01 were inputted into the Ingenuity Pathway Knowledge Base Library to generate gene-interaction networks. After a 6-month aerobic exercise-training, genes promoting inflammation became down-regulated, whereas genes having anti-inflammatory properties and those modulating immune function or promoting neuron survival and axon growth, became up-regulated (all fold change≥±2.0, p<0.01). These changes were not observed in the stretch group. Importantly, the differences in the expression profiles correlated with significant improvement in maximal oxygen uptake (VO2max) in the aerobic program as opposed to the stretch group. We conclude that three distinct cellular pathways may collectively influence the training effects of aerobic exercise in MCI subjects. We plan to confirm these effects using rt-PCR and correlate such changes with the cognitive phenotype.

Normal exercise blood pressure response in African-American women with parental history of hypertension.

BACKGROUND: Genetic and environmental hypotheses may explain why normotensive persons at high risk of developing hypertension often exhibit greater cardiovascular reactivity to stressors than those at low risk. METHODS: Pearson's correlation was used to evaluate reproducibility and independent t test to compare the cardiovascular responses to 30 W of exercise of normotensive young adult African-American women with positive and negative parental histories (PH) of hypertension (PH, n = 23; PH, n = 20). RESULTS: Correlations were significant for duplicate measurements. The effects of PH on blood pressure measured at rest and during exercise were not statistically significant (P > 0.1). A nearly significant trend for greater resting (.-)VO(2) (P = 0.08) was detected in the PH than in the PH group (3.67 +/- 0.18 versus 3.26 +/- 0.14 mL/kg/min). CONCLUSION: A hyper-reactive blood pressure response to exercise, characteristic of the evolution of hypertension, may not be present among the normotensive female offspring of hypertensive African Americans. The significance of an 11% intergroup difference in the mean resting (.-)VO(2) observed in this study is unclear.

Correlates of serum lipoprotein (A) in children and adolescents in the United States. The third National Health Nutrition and Examination Survey (NHANES-III).

OBJECTIVE: To determine the correlates of serum lipoprotein (a) (Lp(a)) in children and adolescents in the United States. METHODS: Cross-sectional study using representative data from a US national sample for persons aged 4-19 years participating in The Third National Health Nutrition and Examination Survey (NHANES-III). RESULTS: We observed ethnicity-related differences in levels of Lp(a) > 30 mg/dl, with values being markedly higher in African American (black) than nonhispanic white (white) and Mexican American children in multivariate model (P < 0.001). Higher levels of Lp(a) > 30 mg/dl associated with parental history of body mass index and residence in metro compared to nonmetro in Blacks, and high birth weight in Mexican American children in the NHANES-III. In the entire group, total cholesterol (which included Lp(a)) and parental history of premature heart attack/angina before age 50 (P < 0.02) showed consistent, independent, positive association with Lp(a). In subgroup analysis, this association was only evident in white (P = 0.04) and black (P = 0.05) children. However, no such collective consistent associations of Lp(a) were found with age, gender, or birth weight. CONCLUSION: Ethnicity-related differences in mean Lp(a) exist among children and adolescents in the United States and parental history of premature heart attack/angina significantly associated with levels of Lp(a) in children. Further research on the associations of Lp(a) levels in childhood with subsequent risk of atherosclerosis is needed.