Unaltered left ventricular mechanics and remodelling after 12 weeks of resistance exercise training – a longitudinal study in men

Previous longitudinal studies suggest that left ventricular (LV) structure is unaltered with resistance exercise training (RT) in young men. However, evidence from aerobic exercise training suggests that early changes in functional LV wall mechanics may occur prior to and independently of changes in LV size, although short-term changes in LV mechanics and structural remodelling in response to RT protocols have not been reported. Therefore, the purpose of this study was to examine the effects of RT on LV mechanics in healthy men performing 2 different time-under-tension protocols. Forty recreationally trained men (age: 23 ± 3 years) were randomized into 12 weeks of whole-body higher-repetition RT (20–25 repetitions/set to failure at ∼30%–50% 1 repetition maximum (1RM); n = 13), lower-repetition RT (8–12 repetitions/set to failure at ∼75%–90% 1RM; n = 13), or an active control period (n = 14). Speckle tracking echocardiography was performed at baseline and following the intervention period. Neither RT program altered standard measures of LV volumes (end-diastolic volume, end-systolic volume, or ejection fraction; P > 0.05) or indices of LV mechanics (total LV twist, untwisting rate, twist-to-shortening ratio, untwisting-to-twist ratio, or longitudinal strain; P > 0.05). This is the first longitudinal study to assess both LV size and mechanics after RT in healthy men, suggesting a maintenance of LV size and twist mechanics despite peripheral muscle adaptations to the training programs. These results provide no evidence for adverse LV structural or functional remodelling in response to RT in young men and support the positive role of RT in the maintenance of optimal cardiovascular function, even with strenuous RT

Peak oxygen uptake measured during a perceptually-regulated exercise test is reliable in community-based manual wheelchair users

This study aimed to compare test-retest reliability and peak exercise responses from ramp-incremented (RAMP) and maximal perceptually-regulated (PRETmax) exercise tests during arm crank exercise in individuals reliant on manual wheelchair propulsion (MWP). Ten untrained participants (9 male) completed four trials over a 2-week period, performing two RAMP (0-40 W + 5-10 W·min-1) trials one week followed by two PRETmax trials the next, or vice versa. PRETmax consisted of five, 2-min stages performed at Ratings of Perceived Exertion (RPE) 11, 13, 15, 17 and 20. Participants freely changed the power output to match the required RPE. Gas exchange variables, heart rate, power output, RPE and affect were determined throughout trials. The V̇ O2peak from RAMP (14.8 ± 5.5 ml·kg-1 ·min-1 ) and PRETmax (13.9 ± 5.2 ml·kg-1 ·min-1) trials were not different (P = 0.08). Measurement error was 1.7 and 2.2 ml·kg-1 ·min-1 and coefficient of variation 5.9% and 8.1% for measuring V̇ O2peak from RAMP and PRETmax, respectively. Affect was more positive at RPE 13 (P = 0.02), 15 (P = 0.01) and 17 (P = 0.01) during PRETmax. This study shows the PRETmax can be used to measure V̇ O2peak in participants reliant on MWP and leads to a more positive affective response compared to RAMP

Perceptually regulated training does not influence the differentiated RPE response following 16-weeks of aerobic exercise in adults with spinal cord injury

This study investigated the effect of prolonged familiarisation with ratings of perceived exertion (RPE) on the peripheral (RPEP) and central (RPEC) RPE responses to moderate-vigorous exercise in adults with spinal cord injury (SCI). RPEP and RPEC characterize the exertion of the working musculature and cardiorespiratory systems, respectively. Nineteen participants (41.4±11.4 years; 19.2±7.2 ml·kg-1·min-1) with chronic SCI were randomly assigned to RPE-guided (n = 11; EXP) or active control (n = 8; CON) groups. EXP performed 16-weeks of RPE-guided, supervised aerobic training for 20 mins, twice weekly, at RPE 3-6 (Category-Ratio 10 scale). CON had access to the same exercise equipment but received no specific advice on their exercise-training regime. Participants completed a graded exercise test, using an arm crank ergometer, pre- and post-training to determine peak oxygen uptake (V̇O2peak), with RPEP and RPEC recorded every minute throughout tests. Sixteen weeks training did not improve V̇O2peak. RPE decreased post-training at 50% (p = 0.02) and 70% V̇O2peak (p = 0.03), though there was no effect of group at either intensity (p = 0.54, 0.42 respectively). At 70% V̇O2peak RPEP was greater than RPEC (4.2±1.7 vs 3.4±1.8, p < 0.005). Training with RPE-guidance for 16-weeks had no additional effect on the differentiated RPE responses to moderate-vigorous exercise in adults with SCI

Comparison between esophageal and intestinal temperature responses to upper-limb exercise in individuals with spinal cord injury

Objective: Individuals with spinal cord injuries (SCI) may present with impaired sympathetic control over thermoregulatory responses to environmental and exercise stressors, which can impact regional core temperature (Tcore) measurement. The purpose of this study was to investigate whether regional differences in Tcore responses exist during exercise in individuals with SCI. Setting: Rehabilitation centre in Wakayama, Japan. Methods: We recruited 12 men with motor-complete SCI (7 tetraplegia, 5 paraplegia) and 5 able-bodied controls to complete a 30-minute bout of arm-cycling exercise at 50% V̇ O2peak. Tcore was estimated using telemetric pills (intestinal temperature; Tint) and esophageal probes (Teso). Heat storage was calculated from baseline to 15 and 30 minutes of exercise. Results: At 15 minutes of exercise, elevations in Teso (Δ0.39±0.22°C; P<0.05), but not Tint (Δ0.04±0.18°C; P=0.09), were observed in able-bodied men. At 30 minutes of exercise, men with paraplegia and able-bodied men both exhibited increases in Teso (paraplegia: Δ0.56±0.30°C, P<0.05; able-bodied men: Δ0.60±0.31°C, P<0.05) and Tint (paraplegia: Δ0.38±0.33°C, P<0.05; able-bodied men: Δ0.30±0.30°C, P<0.05). Teso began rising 7.2 min earlier than Tint (pooled, P<0.01). Heat storage estimated by Teso was greater than heat storage estimated by Tint at 15 minutes (P=0.02) and 30 minutes (P=0.03) in men with paraplegia. No elevations in Teso, Tint, or heat storage were observed in men with tetraplegia. Conclusions: While not interchangeable, both Teso and Tint are sensitive to elevations in Tcore during arm-cycling exercise in men with paraplegia, although Teso may have superior sensitivity to capture temperature information earlier during exercise

Neuropathogenic Forms of Huntingtin and Androgen Receptor Inhibit Fast Axonal Transport

AbstractHuntington's and Kennedy's disease are autosomal dominant neurodegenerative diseases caused by pathogenic expansion of polyglutamine tracts. Expansion of glutamine repeats must in some way confer a gain of pathological function that disrupts an essential cellular process and leads to loss of affected neurons. Association of huntingtin with vesicular structures raised the possibility that axonal transport might be altered. Here we show that polypeptides containing expanded polyglutamine tracts, but not normal N-terminal huntingtin or androgen receptor, directly inhibit both fast axonal transport in isolated axoplasm and elongation of neuritic processes in intact cells. Effects were greater with truncated polypeptides and occurred without detectable morphological aggregates

Fluctuations in phenylalanine concentrations in phenylketonuria: a review of possible relationships with outcomes.

International audience; Fluctuations in blood phenylalanine concentrations may be an important determinant of intellectual outcome in patients with early and continuously treated phenylketonuria (PKU). This review evaluates the studies on phenylalanine fluctuations, factors affecting fluctuations, and if stabilizing phenylalanine concentrations affects outcomes, particularly neurocognitive outcome. Electronic literature searches of Embase and PubMed were performed for English-language publications, and the bibliographies of identified publications were also searched. In patients with PKU, phenylalanine concentrations are highest in the morning. Factors that can affect phenylalanine fluctuations include age, diet, timing and dosing of protein substitute and energy intake, dietary adherence, phenylalanine hydroxylase genotype, changes in dietary phenylalanine intake and protein metabolism, illness, and growth rate. Even distribution of phenylalanine-free protein substitute intake throughout 24h may reduce blood phenylalanine fluctuations. Patients responsive to and treated with 6R-tetrahydrobiopterin seem to have less fluctuation in their blood phenylalanine concentrations than controls. An increase in blood phenylalanine concentration may result in increased brain and cerebrospinal fluid phenylalanine concentrations within hours. Although some evidence suggests that stabilization of blood phenylalanine concentrations may have benefits in patients with PKU, more studies are needed to distinguish the effects of blood phenylalanine fluctuations from those of poor metabolic control

Roles of Hormone Replacement Therapy and Menopause on Osteoarthritis and Cardiovascular Disease Outcomes: A Narrative Review

Osteoarthritis (OA) is a highly prevalent condition characterized by degradation of the joints. OA and cardiovascular disease (CVD) are leading contributors to disease burden worldwide, with a high level of overlap between the risk factors and occurrence of both conditions. Chief among the risk factors that contribute to OA and CVD are sex and age, which are both independent and interacting traits. Specifically, the prevalence of both conditions is higher in older women, which may be mediated by the occurrence of menopause. Menopause represents a significant transition in a women's life, and the rapid decline in circulating sex hormones, estrogen and progesterone, leads to complex physiological changes. Declines in hormone levels may partially explain the increase in prevalence of OA and CVD in post-menopausal women. In theory, the use of hormone therapy (HT) may buffer adverse effects of menopause; however, it is unclear whether HT offers protective effects for the onset or progression of these diseases. Studies have shown mixed results when describing the influence of HT on disease risk among post-menopausal women, which warrants further exploration. The roles that increasing age, female sex, HT, and CVD play in OA risk demonstrate that OA is a multifaceted condition. This review provides a timely consolidation of current literature and suggests aims for future research directions to bridge gaps in the understanding of how OA, CVD, and HT interact in post-menopausal women

Sampling multiple life stages significantly increases estimates of marine biodiversity

Biodiversity assessments are critical for setting conservation priorities, understanding ecosystem function and establishing a baseline to monitor change. Surveys of marine biodiversity that rely almost entirely on sampling adult organisms underestimate diversity because they tend to be limited to habitat types and individuals that can be easily surveyed. Many marine animals have planktonic larvae that can be sampled from the water column at shallow depths. This life stage often is overlooked in surveys but can be used to relatively rapidly document diversity, especially for the many species that are rare or live cryptically as adults. Using DNA barcode data from samples of nemertean worms collected in three biogeographical regions—Northeastern Pacific, the Caribbean Sea and Eastern Tropical Pacific—we found that most species were collected as either benthic adults or planktonic larvae but seldom in both stages. Randomization tests show that this deficit of operational taxonomic units collected as both adults and larvae is extremely unlikely if larvae and adults were drawn from the same pool of species. This effect persists even in well-studied faunas. These results suggest that sampling planktonic larvae offers access to a different subset of species and thus significantly increases estimates of biodiversity compared to sampling adults alone. Spanish abstract is available in the electronic supplementary material.Fil: Maslakova, Svetlana A.. University of Oregon; Estados UnidosFil: Ellison, Christina I.. University of Oregon; Estados UnidosFil: Hiebert, Terra C.. University of Oregon; Estados UnidosFil: Conable, Frances. University of Oregon; Estados UnidosFil: Heapy, Maureen C.. University of Oregon; Estados UnidosFil: Venera Pontón, Dagoberto E.. Smithsonian Tropical Research Institute; PanamáFil: Norenburg, Jon L.. National Museum Of Natural History. Departamento de Zoología. Area de Invertebrados; Estados UnidosFil: Schwartz, Megan L.. University of Washington; Estados UnidosFil: Boyle, Michael J.. Smithsonian Tropical Research Institute; PanamáFil: Driskell, Amy C.. National Museum Of Natural History. Departamento de Zoología. Area de Invertebrados; Estados UnidosFil: Macdonald, Kenneth S.. National Museum Of Natural History. Departamento de Zoología. Area de Invertebrados; Estados UnidosFil: Zattara, Eduardo Enrique. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigaciones en Biodiversidad y Medioambiente. Universidad Nacional del Comahue. Centro Regional Universidad Bariloche. Instituto de Investigaciones en Biodiversidad y Medioambiente; ArgentinaFil: Collin, Rachel. Smithsonian Tropical Research Institute; Panam

Evaluation of health care providers’ role transition and satisfaction in hospital-at-home for chronic obstructive pulmonary disease exacerbations: a survey study

__Abstract__ __Background__: Hospital-at-home is an accepted alternative for usual hospital treatment for patients with a Chronic Obstructive Pulmonary Disease (COPD) exacerbation. The introduction of hospital-at-home may lead to changes in health care providers’ roles and responsibilit