Weight bearing exercise can elicit similar peak muscle activation as medium–high intensity resistance exercise in elderly women

Abstract

Purpose

To assess whether stepping-based weight bearing exercise (WBE) can elicit peak activation of upper leg muscles similar to resistance exercise (RE) at an intensity required to induce strength gains in elderly women.

Methods

Muscular activation of several upper leg muscles was measured during RE and WBE in a cohort of 19 healthy elderly women (69.3 ± 3.4 years). WBE consisted of forward and lateral stepping with step heights of 10, 20 and 30 cm. Muscular activation was compared to 60% of one-repetition maximum (1-RM) of congruent RE.

Results

Peak activation during WBE was higher than RE at 60% 1-RM during forward and lateral stepping in vastus lateralis starting at 20 cm (p = 0.049 and p = 0.001), and biceps femoris at 30 cm step height (p = 0.024 and p = 0.030). Gluteus maximus peak activation matched RE at 60% 1-RM at 20 and 30 cm step height regardless of step direction (p ≥ 0.077). Peak activation of the rectus femoris and gluteus medius matched RE activation at 60% 1-RM during lateral stepping at 30 cm (p = 0.355 and p = 0.243, respectively) but not during forward stepping. WBE did not induce similar activation as RE in the semitendinosus.

Conclusion

In WBE, most upper leg muscles were recruited at an equal or higher intensity than in RE at 60% 1-RM. Lateral stepping at 30 cm step height showed the highest training potential of all WBE's applied.

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Trends in Racial and Ethnic Disparities in Childhood Asthma in Miami, Florida: 2005–2013

Abstract

Nationally, racial and ethnic disparities in childhood asthma plateaued from 2005 to 2013. We assessed trends in childhood asthma in Miami, Florida using Youth Risk Behavior Surveillance System (YRBSS) data and emergency department (ED) utilization and hospitalization rates by zip code population characteristics. Asthma prevalence in Miami did not vary significantly by race/ethnicity in YRBSS respondents in 2005 (16.2–17.2%, all groups), but rose in African–Americans and Hispanics and declined in Whites by 2013 to 27.9, 20.9 and 12.6%, respectively (P = 0.02). Median asthma ED visit rates rose from 106.8 (2006–2008) to 138.2 (2011–2013; P = 0.004) per 10,000 children. High-poverty and majority African–American zip codes were 6.3 and 7.3 times more likely to have asthma ED visit rates > 200 than others (P < 0.001). In high-poverty zip codes, majority African–American population was not associated with significantly higher ED utilization. In low-poverty zip codes, the association became stronger. Greater poverty explains much, but not all of Miami African–Americans' higher asthma risk.

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Skeletal muscle microvascular and interstitial PO2 from rest to contractions

Abstract

Oxygen pressure (PO₂) gradients across the blood-myocyte interface are required for diffusive O₂ transport thereby supporting oxidative metabolism. The greatest resistance to O₂ flux into skeletal muscle is considered to reside between the erythrocyte surface and adjacent sarcolemma, although this has not been measured during contractions. We tested the hypothesis that O₂ gradients between skeletal muscle microvascular (PO₂mv) and interstitial (PO₂is) spaces would be present at rest and maintained or increased during contractions. PO₂mv and PO₂is were determined via phosphorescence quenching (Oxyphor probes G2 and G4, respectively) in the exposed rat spinotrapezius during the rest-contraction transient (1 Hz, 6 V; n = 8). PO₂mv was higher than PO₂is in all instances from rest (34.9 ± 6.0 vs. 15.7 ± 6.4) to contractions (28.4 ± 5.3 vs. 10.6 ± 5.2 mmHg; respectively) such that the mean PO₂ gradient throughout the transient was 16.9 ± 6.6 mmHg (P < 0.05 for all). No differences in the amplitude of PO₂ fall with contractions were observed between the microvasculature and interstitium (10.9 ± 2.3 vs. 9.0 ± 3.5 mmHg, respectively; P > 0.05). However, the speed of the PO₂is fall during contractions was slower than that of PO₂mv (time constant: 12.8 ± 4.7 vs. 9.0 ± 5.1 s, respectively; P < 0.05). Consistent with our hypothesis, a significant transmural gradient was sustained (but not increased) from rest to contractions. This supports that the blood-myocyte interface is the site of a substantial PO₂ gradient driving O₂ diffusion during metabolic transients. Based on Fick's law, elevated O₂ flux with contractions must thus rely primarily on modulations in effective diffusing capacity (mainly erythrocyte hemodynamics and distribution) as the PO₂ gradient is not increased.

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Paramedic - Winona Area Ambulance Service Inc.

Responds to emergent and non-emergent requests for emergency medical assistance under the guidelines of local medical direction. ESSENTIAL DUTIES AND RESPONSIBILITIES: 1. Demonstrate knowledge and understanding of, and compliance with, all Winona Area Ambulance Service policies and procedures. 2. Demonstrate the attitude of a Health Care Professional to include, but not be limited to: maintaining a ...

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The Baby Boom and later life: is critical care fit for the future?

Populations around the world are ageing while in many developed countries the proportion of elderly patients admitted to critical care is rising. It is clear that age alone should not be used as a reason for refusing intensive care admission. Critical care in this patient group is challenging in many ways: with advancing age, several physiological changes occur which all lead to a subsequent reduction of physical performance and compensatory capacity, in many cases additionally aggravated by chronic illness. Subsequently, these age-dependent changes (with or without chronic illness) increase the risk for death, treatment costs and a prolonged length of intensive care and hospital stay. This review explores the potential of using co-morbidity and frailty to predict outcome and to help to make better decisions about critical care admission in the elderly. The authors explore the challenges of using different frailty assessment tools and offer a model for holistic approach to answer these questions.

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Presynaptic serotonin 5-HT 1B/D receptor-mediated inhibition of glycinergic transmission to the frog spinal motoneurons

Abstract

Endogenous monoamine 5-hydroxytryptamine (5-HT, serotonin) is a phylogenetically ancient neurotransmitter present in vertebrates. The functions of 5-HT in central nervous system are intensively studied; however, the presynaptic effects of 5-HT in frog spinal motoneurons are practically unexplored. We have previously shown that 5-HT decreases the frequency of glycinergic miniature inhibitory postsynaptic potentials (mIPSPs), but does not affect the frequency of GABAergic mIPSPs and increases the frequency of glutamatergic postsynaptic potentials. In the present study, using pharmacological methods and intracellular recordings in motoneurons from an adult frog's isolated spinal cord, we aimed to identify the 5-HT receptor subtype responsible for inhibiting the release of glycine. Аn agonist of 5-HT_1A and 5-HT₇ receptors, 8-OH-DPAT, and a selective agonist of 5-HT₂ receptors, α-Ме-5-НТ, did not show any significant effect on inhibitory transmission, indicating that 5-HT_1A, 5-HT_2, and 5-HT₇ receptors are not involved in the modulation of glycine release in the adult frog spinal cord. An agonist of 5-HT_1B/D receptors sumatriptan decreased the frequency (but not the amplitude) of glycinergic mIPSPs similar to 5-HT. An antagonist of 5-HT_1,2 receptors, methysergide, abolished the effect of sumatriptan. Together our results suggest that 5-HT inhibits the release of glycine by activation of 5-HT_1B/D receptors.

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Climate change and landscape development in post-closure safety assessment of solid radioactive waste disposal: Results of an initiative of the IAEA

Publication date: March 2018
Source:Journal of Environmental Radioactivity, Volume 183
Author(s): T. Lindborg, M. Thorne, E. Andersson, J. Becker, J. Brandefelt, T. Cabianca, M. Gunia, A.T.K. Ikonen, E. Johansson, V. Kangasniemi, U. Kautsky, G. Kirchner, R. Klos, R. Kowe, A. Kontula, P. Kupiainen, A.-M. Lahdenperä, N.S. Lord, D.J. Lunt, J.-O. Näslund, M. Nordén, S. Norris, D. Pérez-Sánchez, A. Proverbio, K. Riekki, A. Rübel, L. Sweeck, R. Walke, S. Xu, G. Smith, G. Pröhl
The International Atomic Energy Agency has coordinated an international project addressing climate change and landscape development in post-closure safety assessments of solid radioactive waste disposal. The work has been supported by results of parallel on-going research that has been published in a variety of reports and peer reviewed journal articles. The project is due to be described in detail in a forthcoming IAEA report. Noting the multi-disciplinary nature of post-closure safety assessments, here, an overview of the work is given to provide researchers in the broader fields of radioecology and radiological safety assessment with a review of the work that has been undertaken. It is hoped that such dissemination will support and promote integrated understanding and coherent treatment of climate change and landscape development within an overall assessment process.The key activities undertaken in the project were: identification of the key processes that drive environmental change (mainly those associated with climate and climate change), and description of how a relevant future may develop on a global scale; development of a methodology for characterising environmental change that is valid on a global scale, showing how modelled global changes in climate can be downscaled to provide information that may be needed for characterising environmental change in site-specific assessments, and illustrating different aspects of the methodology in a number of case studies that show the evolution of site characteristics and the implications for the dose assessment models.Overall, the study has shown that quantitative climate and landscape modelling has now developed to the stage that it can be used to define an envelope of climate and landscape change scenarios at specific sites and under specific greenhouse-gas emissions assumptions that is suitable for use in quantitative post-closure performance assessments. These scenarios are not predictions of the future, but are projections based on a well-established understanding of the important processes involved and their impacts on different types of landscape. Such projections support the understanding of, and selection of, plausible ranges of scenarios for use in post-closure safety assessments.



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