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Department of Nutrition, Food and Exercise Sciences

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Acute and timing effects of beta-hydroxy-beta-methylbutyrate (HMB) on indirect markers of skeletal muscle damage.
Acute and timing effects of beta-hydroxy-beta-methylbutyrate (HMB) on indirect markers of skeletal muscle damage.
While chronic β-Hydroxy β-Methylbutyrate (HMB) supplementation (≥ 2 wk) lowers exercise induced muscle damage, its acute or timing effects have not been examined. The purpose of this study was to investigate the acute and timing effects of oral HMB supplementation on serum creatine kinase (CK), lactate dehydrogenase (LDH), muscle soreness, and maximal voluntary contraction (MVC). Sixteen non-resistance trained men (22 ± 2 yrs) were assigned to HMB-Pre or HMB-Post groups. In a crossover design, all subjects performed 55 maximal eccentric knee extension/flexion contractions on 2 occasions on either the right or left leg. HMB-Pre (N = 8) randomly received 3 grams of either a placebo or HMB before and a placebo after exercise. HMB-Post (N = 8) received a placebo before and either 3 grams of HMB or a placebo after exercise. Muscle damage tests were recorded before, at 8, 24, 48, and 72 hrs post exercise. There was a reduction in MVC and an increase in soreness in the quadriceps and hamstrings following exercise (p < 0.001). Although HMB-Pre approached significance in attenuating soreness for the quadriceps (p = 0.07), there was no time x group effect. Serum indices of damage increased, peaking at 48 hrs for CK (773%) (p < 0.001) and 72 hrs for LDH (180%) (p < 0.001). While there were no time x group effects of HMB on CK and LDH, post hoc analysis revealed that only HMB-Pre showed no significant increase in LDH levels following exercise. Our findings suggest no clear acute or timing effects of HMB supplementation. However, consuming HMB before exercise appeared to prevent increases in LDH., Publication Note: This NIH-funded author manuscript originally appeared in PubMed Central at https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2642830.
Acute exercise with whole-body vibration decreases wave reflection and leg arterial stiffness.
Acute exercise with whole-body vibration decreases wave reflection and leg arterial stiffness.
Whole-body vibration exercise (WBV) acutely decreases brachial-ankle pulse wave velocity (baPWV), an index of systemic arterial stiffness. However, the effect of WBV on segmental PWV and aortic hemodynamics is unknown. We examined the acute effects of WBV on arterial function. Fifteen young men performed ten 1-min sets of static squat with WBV (40 Hz, 1 mm, 5.37 G) and without WBV (no-WBV). Brachial and aortic blood pressure (BP), heart rate (HR), augmentation index (AIx), baPWV, carotid-femoral PWV (cfPWV), and femoral-ankle (faPWV), were recorded before and 5, 15, and 30 min after both trials. Brachial and aortic SBP (P < 0.01), and HR (P < 0.01) were increased only at 5 min after both exercise trials. AIx was elevated through the recovery after no-WBV while decreased at 15 and 30 min after WBV exercise. FaPWV was decreased (P < 0.01) at 5 min after both trials, but returned to baseline at 15 min after no-WBV exercise and was maintained decreased at 15 and 30 min after WBV exercise. There were no significant changes in brachial and aortic diastolic BP, cfPWV and baPWV after both trials. Our findings indicate that regardless of WBV, static squat causes a small transient increase in hemodynamic responses during early recovery. WBV counteracts the increase in AIx induced by static squat and reduces wave reflection magnitude through a local effect on arterial stiffness., Keywords: Aortic hemodynamics, Pulse wave velocity, Static exercise, Wave reflection, Publication Note: This NIH-funded author manuscript originally appeared in PubMed Central at https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3253511.
Aerobic Exercise and Whole-Body Vibration in Offsetting Bone Loss in Older          Adults
Aerobic Exercise and Whole-Body Vibration in Offsetting Bone Loss in Older Adults
Osteoporosis and its associated fractures are common complications of aging and most strategies to prevent and/or treat bone loss focused on antiresorptive medications. However, aerobic exercise (AEX) and/or whole-body vibration (WBV) might have beneficial effect on bone mass and provide an alternative approach to increase or maintain bone mineral density (BMD) and reduce the risk of fractures. The purpose of this paper was to investigate the potential benefits of AEX and WBV on BMD in older population and discuss the possible mechanisms of action. Several online databases were utilized and based on the available literature the consensus is that both AEX and WBV may increase spine and femoral BMD in older adults. Therefore, AEX and WBV could serve as nonpharmacological and complementary approaches to increasing/maintaining BMD. However, it is uncertain if noted effects could be permanent and further studies are needed to investigate sustainability of either type of the exercise., Keywords: aerobic exercise, whole body vibration, bone mineral density, osteoporosis, Note: Published online in J Aging Res. 2011 Jan 3;2011:379674. doi: 10.4061/2011/379674, Citation: Liu PY, Brummel-Smith K, Ilich JZ, Aerobic Exercise and Whole-Body Vibration in Offsetting Bone Loss in Older Adults, Journal of Aging Research, vol. 2011, Article ID 379674, 2011.
Apollo Lunar Astronauts Show Higher Cardiovascular Disease Mortality
Apollo Lunar Astronauts Show Higher Cardiovascular Disease Mortality
As multiple spacefaring nations contemplate extended manned missions to Mars and the Moon, health risks could be elevated as travel goes beyond the Earth's protective magnetosphere into the more intense deep space radiation environment. The primary purpose of this study was to determine whether mortality rates due to cardiovascular disease (CVD), cancer, accidents and all other causes of death differ in (1) astronauts who never flew orbital missions in space, (2) astronauts who flew only in low Earth orbit (LEO), and (3) Apollo lunar astronauts, the only humans to have traveled beyond Earth's magnetosphere. Results show there were no differences in CVD mortality rate between non-flight (9%) and LEO (11%) astronauts. However, the CVD mortality rate among Apollo lunar astronauts (43%) was 4-5 times higher than in non-flight and LEO astronauts. To test a possible mechanistic basis for these findings, a secondary purpose was to determine the long-term effects of simulated weightlessness and space-relevant total-body irradiation on vascular responsiveness in mice. The results demonstrate that space-relevant irradiation induces a sustained vascular endothelial cell dysfunction. Such impairment is known to lead to occlusive artery disease, and may be an important risk factor for CVD among astronauts exposed to deep space radiation., Keywords: cancellous bone, cancer, circulatory disease, exploration, exposure, health, ionizing-radiation, mice, risk, vasodilation, Publication Note: The publisher’s version of record is available at https://doi.org/10.1038/srep29901
Are new generations of female college-student populations meeting calcium requirements
Are new generations of female college-student populations meeting calcium requirements
We compared calcium (Ca) sources and intake, as well as multivitamin/mineral supplement use between female students with nutrition/health background and those from general-student-populations. 314 participants 18-37 y, including 57 African-Americans and 54 Caucasian-Americans recruited from Nutrition and/or other Health Sciences departments (NHS), and 100 African-American and 103 Croatian women representing general-student-population (GSP), completed food frequency questionnaire assessing their usual Ca intake and supplement use. NHS populations met recommendations and consumed significantly more Ca, particularly from dairy sources, and were more likely to take supplements than GSP groups, suggesting that health education may influence Ca intake., Keywords: BMI, Dairy, Food frequency questionnaire, Multivitamin/mineral supplements, Publication Note: This NIH-funded author manuscript originally appeared in PubMed Central at https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3257667.
Beta-hydroxy-beta-methyl-butyrate blunts negative age-related changes in body composition, functionality and myofiber dimensions in rats.
Beta-hydroxy-beta-methyl-butyrate blunts negative age-related changes in body composition, functionality and myofiber dimensions in rats.
To determine the effects of 16 wk. of beta-hydroxy-beta-methylbutyrate (HMB) administration on age-related changes in functionality and diffusion tensor imaging (DTI) determined myofiber dimensions. Twelve young (44 wk.), 6 middle-aged (60 wk.), 10 old (86 wk.), and 5 very old (102 wk.) male Fisher-344 rat's body composition and grip strength were assessed at baseline. Following, 6 young, 6 middle-aged, 5 old and 5 very old rats were sacrificed for baseline myofiber dimensions and gene transcript factor expression in the soleus (SOL) and gastrocnemius (GAS). The remaining 6 young and 5 old rats were given HMB for 16 wk. and then sacrificed. Fat mass increased in the middle-aged control condition (+49%) but not the middle-aged HMB condition. In addition, fat mass declined (-56%) in the old HMB condition but not the old control condition. Normalized strength declined and maintained respectively in the control and HMB conditions from 44 to 60 wk. and increased (+23%) (p < 0.05) from 86 to 102 wk. in only the HMB condition. Declines occurred in myofiber size in all muscles from 44 to 102 wk. in the control condition(-10 to -15%), but not HMB condition. Atrogin-1 mRNA expression in the SOL and GAS muscles was greater in the 102-wk control condition than all other conditions: SOL (+45%) and GAS (+100%). This elevation was blunted by HMB in the 102 wk. old SOL. There was a condition effect in the SOL for myogenin, which significantly increased (+40%) only in the 102-wk. HMB group relative to the 44-wk. group. HMB may blunt age-related losses of strength and myofiber dimensions, possibly through attenuating the rise in protein breakdown., Publication Note: This NIH-funded author manuscript originally appeared in PubMed Central at https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3356228.
Bone-Protective Effects of Dried Plum in Postmenopausal Women
Bone-Protective Effects of Dried Plum in Postmenopausal Women
Osteoporosis is an age-related chronic disease characterized by a loss of bone mass and quality, and is associated with an increased risk of fragility fractures. Postmenopausal women are at the greatest risk of developing osteoporosis due to the cessation in ovarian hormone production, which causes accelerated bone loss. As the demographic shifts to a more aged population, a growing number of postmenopausal women will be afflicted with osteoporosis. Certain lifestyle factors, including nutrition and exercise, are known to reduce the risk of developing osteoporosis and therefore play an important role in bone health. In terms of nutrition, accumulating evidence suggests that dried plum (Prunus domestica L.) is potentially an efficacious intervention for preventing and reversing bone mass and structural loss in an ovariectomized rat model of osteoporosis, as well as in osteopenic postmenopausal women. Here, we provide evidence supporting the efficacy of dried plum in preventing and reversing bone loss associated with ovarian hormone deficiency in rodent models and in humans. We end with the results of a recent follow-up study demonstrating that postmenopausal women who previously consumed 100 g dried plum per day during our one-year clinical trial conducted five years earlier retained bone mineral density to a greater extent than those receiving a comparative control. Additionally, we highlight the possible mechanisms of action by which bioactive compounds in dried plum exert bone-protective effects. Overall, the findings of our studies and others strongly suggest that dried plum in its whole form is a promising and efficacious functional food therapy for preventing bone loss in postmenopausal women, with the potential for long-lasting bone-protective effects., Keywords: (poly)phenols, Bioactive compounds, Functional foods, Menopause, Nutrition, Osteopenia, Osteoporosis, Polyphenols, Prune, Publication Note: This NIH-funded author manuscript originally appeared in PubMed Central at https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5452226.
Comparative Effectiveness of Plantar-Massage Techniques on Postural Control in Those With Chronic Ankle Instability.
Comparative Effectiveness of Plantar-Massage Techniques on Postural Control in Those With Chronic Ankle Instability.
  One of the major concerns after an acute lateral ankle sprain is the potential for development of chronic ankle instability (CAI). The existing research has determined that clinician-delivered plantar massage improves postural control in those with CAI. However, the effectiveness of self-administered treatments and the underlying cause of any improvements remain unclear.   To determine (1) the effectiveness of a self-administered plantar-massage treatment in those with CAI and (2) whether the postural-control improvements were due to the stimulation of the plantar cutaneous receptors.   Crossover study.   University setting.   A total of 20 physically active individuals (6 men and 14 women) with self-reported CAI.   All participants completed 3 test sessions involving 3 treatments: a clinician-delivered manual plantar massage, a patient-delivered self-massage with a ball, and a clinician-delivered sensory brush massage.   Postural control was assessed using single-legged balance with eyes open and the Star Excursion Balance Test.   Static postural control improved (P ≤ .014) after each of the interventions. However, no changes in dynamic postural control after any of the interventions were observed (P > .05). No differences were observed between a clinician-delivered manual plantar massage and either a patient-delivered self-massage with a ball or a clinician-delivered sensory brush massage in any postural-control outcome.   In those with CAI, single 5-minute sessions of traditional plantar massage, self-administered massage, and sensory brush massage each resulted in comparable static postural-control improvements. The results also provide empirical evidence suggesting that the mechanism for the postural-control improvements is the stimulation of the plantar cutaneous receptors., Keywords: Balance, Plantar cutaneous receptors, Self-administered treatment, Publication Note: This NIH-funded author manuscript originally appeared in PubMed Central at https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5517117.
Comparison of oxygenation in peripheral muscle during submaximal aerobic exercise, in persons with COPD and healthy, matched-control persons.
Comparison of oxygenation in peripheral muscle during submaximal aerobic exercise, in persons with COPD and healthy, matched-control persons.
The purpose of this study was to compare peripheral muscle oxygenation in persons with chronic obstructive pulmonary disease (COPD) to healthy control persons, during submaximal exercise. Eight persons with COPD (forced expiratory volume in one second [FEV1] = 1.00 +/- 0.27 L) and eight healthy control persons (FEV, = 1.88 +/- 0.55L) performed a submaximal graded exercise test (GXT), and completed 4 min of constant load exercise (CON) at 50% of peak GXT. Measurements included oxygen uptake, heart rate, arterial oxygen saturation and peripheral muscle oxygenation (%StO2) at rest, during exercise, and recovery. Significantly greater workloads were attained for controls compared with COPD for peak GXT and CON. No significant differences in %StO2 were observed between groups at: rest (GXT: 29.5 +/- 22.8 vs 30.4 +/- 17.3%; CON: 33.3 +/- 15.4 vs 35.1 +/- 17.2%); peak GXT (29.4 +/- 19.4 vs 26.5 +/- 15.9%); 4 min of CON (25.9 +/- 13.5 vs 34.5 +/- 21.8%); and recovery (GXT: 46.6 +/- 29.1 vs 44.3 +/- 21.7%; CON: 40.9 +/- 21.5 vs 44.5 +/- 23.2%). These results suggest that peripheral skeletal muscle oxygenation is not compromised in COPD during submaximal exercise, and limitations in exercise capacity are most likely a result of muscle disuse and poor lung function., Publication Note: This NIH-funded author manuscript originally appeared in PubMed Central at https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2707799.
Cooccurrence of Obesity, Osteoporosis, and Sarcopenia in the Ovariectomized Rat
Cooccurrence of Obesity, Osteoporosis, and Sarcopenia in the Ovariectomized Rat
Obesity, osteoporosis, and sarcopenia may individually occur due to age-related gradual alterations in body composition. This study investigates the cooccurrence of these age-related diseases in female animals with low levels of ovarian hormone in the absence of complex multifactorial process of chronological aging. Thirty-six 5- and 10-month-old female rats were chosen to model pre- and postmenopausal women, respectively. Rats were divided into three treatment groups in each age category-sham, ovariectomized (ovx), and ovx + E2 (17β-estradiol, 10 μg/kg)-and were pair-fed. Volunteer wheel running activity, body composition, bone microstructure, serum C-telopeptides of type I collagen, bone specific alkaline phosphatase, E2, and gastrocnemius and soleus muscles were analyzed. The cooccurrence of osteoporosis, sarcopenia, and obesity was observed in the older ovx rats associated with a significant (p < 0.05) increased fat mass (30%), bone loss (9.6%), decreased normalized muscle mass-to-body-weight ratio (10.5%), and a significant decrease in physical activity (57%). The ratio of tibial bone mineral density to combined muscle mass was significantly decreased in both ovx age categories. Ovariectomized rat could be used as an experimental model to examine the effect of loss of ovarian hormones, while controlling for energy intake and expenditure, to conduct obesity and body composition translational research in females without the confounding effect of genetic background., Publication Note: This NIH-funded author manuscript originally appeared in PubMed Central at https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5471594.
Detection Of Shiga Toxin-producing Escherichia Coli, Stx(1), Stx(2) And Salmonella By Two High Resolution Melt Curve Multiplex Real-time Pcr
Detection Of Shiga Toxin-producing Escherichia Coli, Stx(1), Stx(2) And Salmonella By Two High Resolution Melt Curve Multiplex Real-time Pcr
In the United States, Shiga toxin-producing Escherichia coli (STEC) O157 and six non-O157 serogroups O26, O45, O103, O111, O121 and O145 are considered adulterants in non-intact beef. Further, Salmonella is responsible for one of the highest numbers of foodborne infections worldwide. Multiple foods, especially meats, are routinely tested for these pathogens using methods like PCR. However, with such a large group of organisms, multiplexing using probe-based PCR assays is expensive due to the need for differently labeled oligonucleotide probes and sophisticated instrumentation. The aim of this study was to design low-cost multiplex real-time PCR assays for the detection of seven STEC serogroups, stx(1), stx(2) genes and virulent Salmonella. Two multiplex real-time PCR melt curve assays with internal amplification controls (1AG) were standardized. The first assay detected E. coli O121, E. coli O145, E. coli O157, stx(1), and stx(2). The second assay targeted E. coli O26, E. coli O111, E. coil O103, E. coli O45, and Salmonella. Ground beef and beef trim inoculated with 5-27 CFU/325 g of STEC and 9-36 CFU/325 g of Salmonella could be detected following an 8-10 h enrichment at 40 degrees C +/- 2 degrees C in buffered peptone water containing 8 mg/L vancomycin. The assays showed reproducible results for beef products with different fat contents. These assays do not rely on fluorescent-labeled probes or immunomagnetic beads, yet accurately detect seven STEC serogroups, seven stx gene subtypes and Salmonella, making them suitable for routine testing of STEC and Salmonella in beef., Keywords: assay, cattle, High resolution melt curve (HRM), in-ground beef, o103, o111, o145, o157-h7, Real time PCR, reliable detection, Salmonella, serogroups o26, Shiga toxin-producing Escherichia coli (STEC), strains, Publication Note: The publisher's version of record is available at https://doi.org/10.1016/j.foodcont.2018.09.024
Diabetic indicators are the strongest predictors for cardiovascular disease risk in African American adults
Diabetic indicators are the strongest predictors for cardiovascular disease risk in African American adults
African Americans have higher risk of developing type 2 diabetes and cardiovascular disease (CVD) compared to other racial groups. Modifiable and non-modifiable factors play a role in the development of both diseases. This study assessed diabetes indicators in relation to other CVD risk factors taking into account confounders, among African American adults. This was a cross-sectional study in mid-life and older African Americans (>= 45 years) who were recruited from the local churches. Fasting blood was collected and serum analyzed for diabetes indicators, apolipoproteins, adipokines, and lipid profile. CVD risk scores were determined using the American Heart Association and Framingham Risk Score assessments. Homeostasis Model Assessments (HOMAs) were calculated using glucose and insulin concentrations. Confounding variables were assessed by questionnaires. Data were analyzed using SPSS software, version 21, and p<0.05 was deemed significant. Descriptive statistics was used to analyze continuous variables. Frequencies and percentages were used to examine categorical variables. T-tests compared different groups while Pearson correlations provided preliminary relationships and determined variables for multiple regression analyses. A total of n=79 participants were evaluated (69% women), 59.3+/-9.2 years, BMI=34.7+/-8.3 (mean+/-SD). As expected, AA men had higher fasting blood glucose than women (123.6+/-54.9 mg/dL versus 99.0+/-21.8 mg/dL), and AA women had higher insulin (11.8+/-13.1 mg/dL versus 7.6+/-6.0 mg/dL). Our study confirmed that it is likely for AA men to have significantly lower adiponectin concentrations in comparison to AA women. Based on the CVD risk assessments, men had a significantly higher risk of developing CVD than women, which has been shown previously. Apolipoproteins, adipokines, and lipid profile also negatively influenced the cardiovascular health outcomes in men. Dietary intake, probably by influencing participants' weight/adiposity, contributed to the differences in cardiovascular outcomes between men and women. In conclusion, the findings of this study revealed that diabetes and serum glucose appeared to be the leading factors for high CVD risk, on the contrary to some other indicators reported in some studies, e.g. hypertension or dyslipidemia., Keywords: African Americans, Aging, association, atherosclerosis, blood glucose, blood-pressure, cardiovascular disease risk, diet, health, impaired glucose-tolerance, insulin, metabolic syndrome, overweight, postmenopausal women, racial/ethnic differences, Type 2 diabetes
Dietary advanced glycation end-products exacerbate oxidative stress in patients with diabetic foot ulcers
Dietary advanced glycation end-products exacerbate oxidative stress in patients with diabetic foot ulcers
Keywords: Diabetes mellitus, wound healing, obesity, nutrition, inflammation, Publication Note: © 2014 Spicer et al; licensee Herbert Publications Ltd. http://dx.doi.org/10.7243/2050-0866-3-2 This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Effects Of Pharmacologic Sclerostin Inhibition Or Testosterone Administration On Soleus Muscle Atrophy In Rodents After Spinal Cord Injury
Effects Of Pharmacologic Sclerostin Inhibition Or Testosterone Administration On Soleus Muscle Atrophy In Rodents After Spinal Cord Injury
Sclerostin is a circulating osteocyte-derived glycoprotein that negatively regulates Wnt-signaling after binding the LRP5/LRP6 co-receptors. Pharmacologic sclerostin inhibition produces bone anabolic effects after spinal cord injury (SCI), however, the effects of sclerostin-antibody (Scl-Ab) on muscle morphology remain unknown. In comparison, androgen administration produces bone antiresorptive effects after SCI and some, but not all, studies have reported that testosterone treatment ameliorates skeletal muscle atrophy in this context. Our purposes were to determine whether Scl-Ab prevents hindlimb muscle loss after SCI and compare the effects of Scl-Ab to testosterone enanthate (TE), an agent with known myotrophic effects. Male Sprague-Dawley rats aged 5 months received: (A) SHAM surgery (T8 laminectomy), (B) moderate-severe contusion SCI, (C) SCI+TE (7.0 mg/wk, im), or (D) SCI+Scl-Ab (25 mg/kg, twice weekly, sc). Twenty-one days post-injury, SCI animals exhibited a 31% lower soleus mass in comparison to SHAM, accompanied by >50% lower soleus muscle fiber cross-sectional area (fCSA) (p<0.01 for all fiber types). Scl-Ab did not prevent soleus atrophy, consistent with the relatively low circulating sclerostin concentrations and with the 91-99% lower LRP5/LRP6 gene expressions in soleus versus tibia (p<0.001), a tissue with known anabolic responsiveness to Scl-Ab. In comparison, TE partially prevented soleus atrophy and increased levator ani/bulbocavernosus (LABC) mass by 30-40% (p<0.001 vs all groups). The differing myotrophic responsiveness coincided with a 3-fold higher androgen receptor gene expression in LABC versus soleus (p<0.01). This study provides the first direct evidence that Scl-Ab does not prevent soleus muscle atrophy in rodents after SCI and suggests that variable myotrophic responses in rodent muscles after androgen administration are influenced by androgen receptor expression., Keywords: model, rats, skeletal-muscle, replacement therapy, short-term, bone loss, cast immobilization, hybrid fibers, hypogonadal men, prevents bone, Publication Note: The publisher’s version of record is available at https://doi.org/10.1371/journal.pone.0194440
Effects Of Resting, Consecutive, Long-duration Water Immersions On Neuromuscular Endurance In Well-trained Males
Effects Of Resting, Consecutive, Long-duration Water Immersions On Neuromuscular Endurance In Well-trained Males
Purpose: This study examined the effects of repeated long-duration water immersions (WI)s at 1.35 atmospheres absolute (ATA) on neuromuscular endurance performance. We hypothesized that, following 5 days of consecutive, resting, long-duration WIs, neuromuscular endurance performance would decrease. Methods: Fifteen well-trained, male subjects completed five consecutive 6-h resting WIs with 18-h surface intervals during the dive week while breathing compressed air at 1.35 ATA. Skeletal muscle endurance performance was assessed before and after each WI, and 24 and 72 h after the final WI. Muscular endurance assessments included 40% maximum handgrip endurance (MHE) and 50-repetition maximal isokinetic knee extensions. Near infrared spectroscopy was used to measure muscle oxidative capacity of the vastus lateralis and localized muscle tissue oxygenation of the vastus lateralis and flexor carpi radialis. Simultaneously, brachioradialis neuromuscular activation was measured by surface electromyography. Results: A 24.9% increase (p = 0.04) in the muscle oxidative capacity rate constant (k) occurred on WI 4 compared to baseline. No changes occurred in 40% MHE time to exhaustion or rate of fatigue or total work performed for the 50-repetition maximal isokinetic knee extension. The first quartile of deoxygenated hemoglobin concentration showed a 6 and 35% increase on WIs 3 and 5 (p = 0.026) with second quartile increases of 9 and 32% on WIs 3 and 5 (p = 0.049) during the 40% MHE testing when compared to WI 1. Conclusion: Our specific WI protocol resulted in no change to muscular endurance and oxygen kinetics in load bearing and non-load bearing muscles., Keywords: exercise, recovery, responses, kinetics, force, contractile properties, short-term, electromyography, muscle oxygenation, muscle oxidative capacity, near-infrared spectroscopy, neuromuscular endurance, peak torque, simulated microgravity, water immersion, Publication Note: The publisher’s version of record is available at https://doi.org/10.3389/fphys.2018.00977
Effects of High-LET Radiation Exposure and Hindlimb Unloading on Skeletal Muscle Resistance Artery Vasomotor Properties and Cancellous Bone Microarchitecture in Mice
Effects of High-LET Radiation Exposure and Hindlimb Unloading on Skeletal Muscle Resistance Artery Vasomotor Properties and Cancellous Bone Microarchitecture in Mice
Weightlessness during spaceflight leads to functional changes in resistance arteries and loss of cancellous bone, which may be potentiated by radiation exposure. The purpose of this study was to assess the effects of hindlimb unloading (HU) and total-body irradiation (TBI) on the vasomotor responses of skeletal muscle arteries. Male C57BL/6 mice were assigned to control, HU (13-16 days), TBI (1 Gy Fe-56, 600 MeV, 10 cGy/min) and HU-TBI groups. Gastrocnemius muscle feed arteries were isolated for in vitro study. Endothelium-dependent (acetylcholine) and -independent (Dea-NONOate) vasodilator and vasoconstrictor (KCl, phenylephrine and myogenic) responses were evaluated. Arterial endothelial nitric oxide synthase (eNOS), superoxide dismutase-1 (SOD-1) and xanthine oxidase (XO) protein content and tibial cancellous bone microarchitecture were quantified. Endothelium-dependent and -independent vasodilator responses were impaired in all groups relative to control, and acetylcholine-induced vasodilation was lower in the HU-TBI group relative to that in the HU and TBI groups. Reductions in endothelium-dependent vasodilation correlated with a lower cancellous bone volume fraction. Nitric oxide synthase inhibition abolished all group differences in endothelium-dependent vasodilation. HU and HU-TBI resulted in decreases in eNOS protein levels, while TBI and HU-TBI produced lower SOD-1 and higher XO protein content. Vasoconstrictor responses were not altered. Reductions in NO bioavailability (eNOS), lower anti-oxidant capacity (SOD-1) and higher pro-oxidant capacity (XO) may contribute to the deficits in NOS signaling in skeletal muscle resistance arteries. These findings suggest that the combination of insults experienced in spaceflight leads to impairment of vasodilator function in resistance arteries that is mediated through deficits in NOS signaling. (C) 2016 by Radiation Research Society, Keywords: blood-flow, endothelium-dependent vasodilation, ionizing-radiation, orthostatic intolerance, Oxidative stress, short-duration spaceflight, simulated microgravity, space exploration, vasoconstrictor responsiveness, xanthine-oxidase, Publication Note: The publisher’s version of record is available at http://www.dx.doi.org/10.1667/RR4308.1
Effects of Obesity on Bone Mass and Quality in Ovariectomized Female Zucker Rats
Effects of Obesity on Bone Mass and Quality in Ovariectomized Female Zucker Rats
Obesity and osteoporosis are two chronic conditions that have been increasing in prevalence. Despite prior data supporting the positive relationship between body weight and bone mineral density (BMD), recent findings show excess body weight to be detrimental to bone mass, strength, and quality. To evaluate whether obesity would further exacerbate the effects of ovariectomy on bone, we examined the tibiae and fourth lumbar (L4) vertebrae from leptin receptor-deficient female (Leprfalfa) Zucker rats and their heterozygous lean controls (Leprafal+) that were either sham-operated or ovariectomized (Ovx). BMD of L4 vertebra was measured using dual-energy X-ray absorptiometry, and microcomputed tomography was used to assess the microstructural properties of the tibiae. Ovariectomy significantly (P < 0.001) decreased the BMD of L4 vertebrae in lean and obese Zucker rats. Lower trabecular number and greater trabecular separation (P < 0.001) were also observed in the tibiae of lean- and obese-Ovx rats when compared to sham rats. However, only the obese-Ovx rats had lower trabecular thickness (Tb.Th) (P < 0.005) than the other groups. These findings demonstrated that ovarian hormone deficiency adversely affected bone mass and quality in lean and obese rats while obesity only affected Tb.Thin Ovx-female Zucker rats., Publication Note: Publisher's Version Also Available at https://www.hindawi.com/journals/jobe/2014/690123/abs/, Preferred Citation: Feresin, R. G., Johnson, S. A., Elam, M. L., Jo, E., Arjmandi, B. H., & Hakkak, R. (2014). Effects of obesity on bone mass and quality in ovariectomized female Zucker rats. Journal of obesity, 2014.
Effects of Resistance Training on Physical Function and Quality of Life in Breast Cancer Survivors.
Effects of Resistance Training on Physical Function and Quality of Life in Breast Cancer Survivors.
Breast cancer survivors (BCS) exhibit decreased physical function and quality of life (QOL) following cancer treatments. Resistance training (RT) may elicit positive changes in physical and mental well-being. This study assessed 27 BCS, pre-and post-intervention (six months) on the following variables: muscular strength (via one repetition maximum (1RM) of chest press and leg extension), physical function (via the Continuous Scale-Physical Functional Performance test) and QOL (via the Short Form-36 survey). RT consisted of two days/week of ten exercises including two sets of 8-12 repetitions at 52%-69% of their 1RM. A repeated measures analysis of variance revealed BCS significantly (p < 0.05) increased upper (71 ± 22 to 89 ± 22 kg) and lower body (74 ± 18 to 93 ± 24 kg) strength, total physical function (65.5 ± 12.1 to 73.6 ± 12.2 units) and the subcomponents of physical function: upper body strength (63.5 ± 16.3 to 71.2 ± 16.8 units), lower body strength (58.5 ± 14.9 to 68.6 ± 16.3 units), balance and coordination (66.5 ± 12.2 to 74.6 ± 11.6 units), and endurance (67.2 ± 12.0 to 75.0 ± 11.6 units). No changes were observed over time for subjective measures of physical function and QOL. Results showed RT could be an effective means to improve objective physical function in BCS. Further research is needed to clarify the effects of RT on subjective physical function and QOL., Keywords: Breast cancer survivors, Physical function, Quality of life, Resistance training, Publication Note: This NIH-funded author manuscript originally appeared in PubMed Central at https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4939569.
Effects of Resting, Consecutive, Long-Duration Water Immersions on Neuromuscular Endurance in Well-Trained Males.
Effects of Resting, Consecutive, Long-Duration Water Immersions on Neuromuscular Endurance in Well-Trained Males.
This study examined the effects of repeated long-duration water immersions (WI)s at 1.35 atmospheres absolute (ATA) on neuromuscular endurance performance. We hypothesized that, following 5 days of consecutive, resting, long-duration WIs, neuromuscular endurance performance would decrease. Fifteen well-trained, male subjects completed five consecutive 6-h resting WIs with 18-h surface intervals during the dive week while breathing compressed air at 1.35 ATA. Skeletal muscle endurance performance was assessed before and after each WI, and 24 and 72 h after the final WI. Muscular endurance assessments included 40% maximum handgrip endurance (MHE) and 50-repetition maximal isokinetic knee extensions. Near infrared spectroscopy was used to measure muscle oxidative capacity of the vastus lateralis and localized muscle tissue oxygenation of the vastus lateralis and flexor carpi radialis. Simultaneously, brachioradialis neuromuscular activation was measured by surface electromyography. A 24.9% increase ( = 0.04) in the muscle oxidative capacity rate constant () occurred on WI 4 compared to baseline. No changes occurred in 40% MHE time to exhaustion or rate of fatigue or total work performed for the 50-repetition maximal isokinetic knee extension. The first quartile of deoxygenated hemoglobin concentration showed a 6 and 35% increase on WIs 3 and 5 ( = 0.026) with second quartile increases of 9 and 32% on WIs 3 and 5 ( = 0.049) during the 40% MHE testing when compared to WI 1. Our specific WI protocol resulted in no change to muscular endurance and oxygen kinetics in load bearing and non-load bearing muscles., Keywords: Electromyography, Muscle oxidative capacity, Near-infrared spectroscopy, Neuromuscular endurance, Water immersion, Publication Note: This NIH-funded author manuscript originally appeared in PubMed Central at https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6072852.
Effects of a 12-Month Pedometer-Based Walking Intervention in Women of Low Socioeconomic Status.
Effects of a 12-Month Pedometer-Based Walking Intervention in Women of Low Socioeconomic Status.
This study examined the effects of a 12-month walking intervention in overweight/obese, low socioeconomic women. Forty-six women (48.2 ± 8.0 years) entered the study. Outcomes included weight, waist and hip circumferences, body mass index (BMI), blood pressure, glycosylated hemoglobin, blood lipids, fibrinogen, and high-sensitivity C-reactive protein (hsCRP). Both intention-to-treat analyses in all participants and group analyses in study completers only (3K group = increased steps/day by ≥3,000; No Δ group = did not increase steps/day by ≥3,000) were conducted. Group × time ANOVA was used. In study completers, 3K significantly increased steps/day (6,903 ± 3,328 to 12,323 ± 5,736) compared to No Δ (4,926 ± 3,374 to 5,174 ± 3,095) from baseline to 12 months. There was a significant time effect for weight (P = 0.030), BMI (P = 0.029), and hsCRP (P = 0.044). Low socioeconomic women who adhere to a long-term, pedometer-based walking intervention significantly increased steps/day and may improve body weight, BMI, and hsCRP. This could help reduce health disparities in this population over time., Keywords: African-American, Cardiometabolic, Cardiovascular disease risk, Low income, Obesity, Overweight, Publication Note: This NIH-funded author manuscript originally appeared in PubMed Central at https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5054940.

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