289 research outputs found

    Cycle training induces muscle hypertrophy and strength gain: strategies and mechanisms

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    Cycle training is widely performed as a major part of any exercise program seeking to improve aerobic capacity and cardiovascular health. However, the effect of cycle training on muscle size and strength gain still requires further insight, even though it is known that professional cyclists display larger muscle size compared to controls. Therefore, the purpose of this review is to discuss the effects of cycle training on muscle size and strength of the lower extremity and the possible mechanisms for increasing muscle size with cycle training. It is plausible that cycle training requires a longer period to significantly increase muscle size compared to typical resistance training due to a much slower hypertrophy rate. Cycle training induces muscle hypertrophy similarly between young and older age groups, while strength gain seems to favor older adults, which suggests that the probability for improving in muscle quality appears to be higher in older adults compared to young adults. For young adults, higher-intensity intermittent cycling may be required to achieve strength gains. It also appears that muscle hypertrophy induced by cycle training results from the positive changes in muscle protein net balance

    Towards the Study of Liver Failure: Protocol for a 90% Extended Hepatectomy in Mice

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    Studies have shown that extended hepatectomy mimics post-hepatectomy liver failure (PHLF) and could also be used to study other small-for-flow syndromes. Extended hepatectomy can be defined as the removal of more than 70% of liver volume. At the molecular level, there seems to be a delayed entrance to the cell cycle, and thus liver dysfunction ensues. Therefore, there is an imperious need to study the mechanisms of such delay to understand how it can be regulated. While the classical 70% hepatectomy model to study liver regeneration has been previously described thoroughly, there are no protocols describing the surgical procedure for a 90% extended hepatectomy (90% EHx). Therefore, we here describe a detailed and reproducible protocol for such model, defining specific aspects that must be considered as well as the most common complications and troubleshooting strategies

    Developmental appearance of factors that bind specifically to cis-regulatory sequences of a gene expressed in the sea urchin embryo

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    Previous gene-transfer experiments have identified a 2500-nucleotide 5' domain of the CyIIIa cytoskeletal actin gene, which contains cis-regulatory sequences that are necessary and sufficient for spatial and temporal control of CyIIIa gene expression during embryogenesis. This gene is activated in late cleavage, exclusively in aboral ectoderm cell lineages. In this study, we focus on interactions demonstrated in vitro between sequences of the regulatory domain and proteins present in crude extracts derived from sea urchin embryo nuclei and from unfertilized eggs. Quantitative gel-shift measurements are utilized to estimate minimum numbers of factor molecules per embryo at 24 hr postfertilization, when the CyIIIa gene is active, at 7 hr, when it is still silent, and in the unfertilized egg. We also estimate the binding affinity preferences (K_r) of the various factors for their respective sites, relative to their affinity for synthetic DNA competitors. At least 14 different specific interactions occur within the regulatory regions, some of which produce multiple DNA-protein complexes. Values of K_r range from approximately 2 x 10^4 to approximately 2 x 10^6 for these factors under the conditions applied. With one exception, the minimum factor prevalences that we measured in the 400-cell 24-hr embryo nuclear extracts fell within the range of 2 x 10^5 to 2 x 10^6 molecules per embryo, i.e., a few hundred to a few thousand molecules per nucleus. Three developmental patterns were observed with respect to factor prevalence: Factors reacting at one site were found in unfertilized egg cytoplasm at about the same level per egg or embryo as in 24-hr embryo nuclei; factors reacting with five other regions of the regulatory domain are not detectable in egg cytoplasm but in 7-hr mid-cleavage-stage embryo, nuclei are already at or close to their concentrations in the 24-hr embryo nuclei; and factors reacting with five additional regions are not detectable in egg cytoplasm and are low in 7-hr embryo nuclei, i.e., ⩽10% per embryo of the level they attain in 24-hr embryo nuclei. The rise in concentration of factors of the latter class could provide the proximal cause for the temporal activation of the CyIIIa gene at the early blastula stage

    Associations between pQCT-based fat and muscle area and density and DXA-based total and leg soft tissue mass in healthy women and men

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    Peripheral Quantitative Computed Tomography (pQCT) can be used for muscle and fat area and density assessments. These may independently influence muscle and fat mass measurements from Dual Energy X-ray Absorptiometry (DXA). Objective: To determine associations between pQCT-derived soft tissue density and area measures and DXA-derived soft tissue mass. Methods: Linear regression models were developed based on BMI and calf fat and muscle cross-sectional area (FCSA and MCSA) and density measured by pQCT in healthy women (n=76) and men (n=82) aged 20-59 years. Independent variables for these models were leg and total bone-free lean mass (BFLM) and fat mass (FM) measured by DXA. Results:Sex differences (p Conclusion: Calf muscle and fat area and density independently predict lean and fat tissue mass

    Measuring and optimising the efficiency of community hospital inpatient care for older people: the MoCHA mixed-methods study

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    Background: Community hospitals are small hospitals providing local inpatient and outpatient services. National surveys report that inpatient rehabilitation for older people is a core function but there are large differences in key performance measures. We have investigated these variations in community hospital ward performance. Objectives: (1) To measure the relative performance of community hospital wards (studies 1 and 2); (2) to identify characteristics of community hospital wards that optimise performance (studies 1 and 3); (3) to develop a web-based interactive toolkit that supports operational changes to optimise ward performance (study 4); (4) to investigate the impact of community hospital wards on secondary care use (study 5); and (5) to investigate associations between short-term community (intermediate care) services and secondary care utilisation (study 5). Methods: Study 1 – we used national data to conduct econometric estimations using stochastic frontier analysis in which a cost function was modelled using significant predictors of community hospital ward costs. Study 2 – a national postal survey was developed to collect data from a larger sample of community hospitals. Study 3 – three ethnographic case studies were performed to provide insight into less tangible aspects of community hospital ward care. Study 4 – a web-based interactive toolkit was developed by integrating the econometrics (study 1) and case study (study 3) findings. Study 5 – regression analyses were conducted using data from the Atlas of Variation Map 61 (rate of emergency admissions to hospital for people aged ≥ 75 years with a length of stay of < 24 hours) and the National Audit of Intermediate Care. Results: Community hospital ward efficiency is comparable with the NHS acute hospital sector (mean cost efficiency 0.83, range 0.72–0.92). The rank order of community hospital ward efficiencies was distinguished to facilitate learning across the sector. On average, if all community hospital wards were operating in line with the highest cost efficiency, savings of 17% (or £47M per year) could be achieved (price year 2013/14) for our sample of 101 wards. Significant economies of scale were found: a 1% rise in output was associated with an average 0.85% increase in costs. We were unable to obtain a larger community hospital sample because of the low response rate to our national survey. The case studies identified how rehabilitation was delivered through collaborative, interdisciplinary working; interprofessional communication; and meaningful patient and family engagement. We also developed insight into patients’ recovery trajectories and care transitions. The web-based interactive toolkit was established [http://mocha. nhsbenchmarking.nhs.uk/ (accessed 9 September 2019)]. The crisis response team type of intermediate care, but not community hospitals, had a statistically significant negative association with emergency admissions. Limitations: The econometric analyses were based on cross-sectional data and were also limited by missing data. The low response rate to our national survey means that we cannot extrapolate reliably from our community hospital sample. Conclusions: The results suggest that significant community hospital ward savings may be realised by improving modifiable performance factors that might be augmented further by economies of scale. Future work: How less efficient hospitals might reduce costs and sustain quality requires further research

    Effect of fibre configurations on mechanical properties of flax/tannin composites.

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    Flax reinforced tannin-based composites have a potential to be used in vehicle applications due to the environmental advantages and good mechanical properties. In this paper, the effects of fibre configuration on mechanical properties of flax/tannin composites were investigated for nonwoven and woven fabric lay-up angles (UD, [0°, 90°]2 and [0°, +45°, 90°, -45°]2). The tannin/flax composites were prepared by compression moulding. The manufactured specimens were then characterized for quasi-static tensile properties, dynamic mechanical properties and low-energy impact performance. Failure mechanism was further investigated using microscopy and demonstrated the need for further adhesion improvements. The study shows that the UD fabric reinforced composite performs better in tensile strength and modulus whereas [0°, +45°, 90°, -45°]2 composite provides the best impact energy absorption performance

    To play or not to play: Can an instrument really impact lip and tongue performance?

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    © 2020 by the authors. Licensee MDPI, Basel, Switzerland. (1) Background: Increasing tongue and lip strength may help improve various speech and swallowing disorders, but it is unclear if instrumentalists who use these muscle groups for long periods of time have greater strength and endurance compared to controls. It is also unclear if instrumentalists can more accurately estimate various exercise intensities. The purpose of this study was to determine differences in lip and tongue strength and endurance between instrumentalists and non-instrumentalists (controls). A secondary purpose was to assess differences in ability to estimate various exercise intensities between the two groups. (2) Methods: Instrumentalists and controls’ maximum strength and endurance were measured using the IOPI Pro medical device. In addition, 40%, 60% and 80% of maximum strength were estimated in a randomized order. (3) Results: No significant differences were found between instrumentalists and controls in strength or endurance or the ability to estimate various intensities. Overall, participants were better at estimating tongue strength at moderate intensities and lip strength at higher intensities. (4) Conclusion: Tongue and lip strength and endurance and the ability to estimate exercise intensities are not impacted by years of instrumentalist training compared to healthy controls

    Influence of anthropometric parameters and biochemical markers of bone metabolism on quantitative ultrasound of bone in the institutionalized elderly

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    The assessment of bone quality by quantitative ultrasound (QUS), a transportable and relatively cheap method, shows some correlations with bone mineral density (BMD) as measured by dual-energy X-ray absorptiometry (DXA) and with fracture risk. To examine its correlation with bone metabolism in a population of institutionalized elderly people known to be at high risk for vitamin D deficiency and secondary hyperparathyroidism, QUS of the calcaneus and biochemical parameters were measured in 264 women aged 85 +/- 7 (SD) years and in 103 men aged 81 +/- 8 years living in 19 nursing homes. Vitamin D deficiency was frequent in this population: 41.9% of the women and 31.4% of the men had a serum 25-hydroxyvitamin (25OHD) level below the 2.5th percentile level of 3276 normal Swiss adults (6.2 micrograms/l or 15.5 mmol/l). Hyperparathyroidism was less frequent: serum parathyroid hormone (PTH) levels were above the 97.5th percentile level of normal adults (70 pg/l) in 18.9% of women and 9.8% of men. In women, QUS data correlated significantly with age (r = -0.297), body mass index (BMI) (r = 0.403), calcium (r = 0.220), PTH (r = -0.296), 25OHD (r = 0.298) and alkaline phosphatase (AP) (r = -0.170) for broadband ultrasound attenuation (BUA), and with age (r = -0.195), BMI (r = 0.208), PTH (r = -0.174), 25OHD (r = 0.140) and AP (r = -0.130) for speed of sound (SOS). In men, ultrasound data correlated with BMI (r = 0.326), calcium (r = 0.199), 25OHD (r = 0.258) and AP (r = -0.311) for BUA, and with AP (r = -0.196) for SOS. In women, but not in men because of their smaller number, a multivariate analysis was performed to examine relationships between age, BMI, biochemical markers and QUS. Age, BMI, PTH and phosphate explained 30% of the variance of BUA and 10% for SOS. In conclusion, QUS of bone evaluates characteristics of bone that are influenced, at least partially, by age, BMI and the secondary hyperparathyroidism due to vitamin D deficiency

    Intersecting batteries of differentially expressed genes in the early sea urchin embryo

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    We determined the distribution of cis-regulatory sites, previously identified in the control domain of the CyIIIa gene, in three other genes displaying diverse spatial patterns of expression in the sea urchin embryo. Competitive gel-shift reactions were carried out using probes from the CyIIIa gene, with competitor fragments isolated from the previously defined control domains of the other genes. CyIIIa is expressed only in aboral ectoderm lineages; the other genes studied were Spec1, also expressed in aboral ectoderm; CyI, expressed in many different cell types; and SM50, expressed only in skeletogenic mesenchyme. All four genes are activated at about the same time in late cleavage. Where competitive interactions indicated a functionally comparable binding site (in vitro), a sequence homology was sought, and in most cases could be identified. An interesting pattern of putative regulatory site usage emerges: Of 10 CyIIIa interactions tested, three only were unique to the CyIIIa gene with respect to the set of four genes tested; one believed on previous evidence to be a temporal regulator was shared by all four genes, and the remainder were shared in various subsets of the four genes

    Developmental appearance of factors that bind specifically to cis-regulatory sequences of a gene expressed in the sea urchin embryo

    Get PDF
    Previous gene-transfer experiments have identified a 2500-nucleotide 5' domain of the CyIIIa cytoskeletal actin gene, which contains cis-regulatory sequences that are necessary and sufficient for spatial and temporal control of CyIIIa gene expression during embryogenesis. This gene is activated in late cleavage, exclusively in aboral ectoderm cell lineages. In this study, we focus on interactions demonstrated in vitro between sequences of the regulatory domain and proteins present in crude extracts derived from sea urchin embryo nuclei and from unfertilized eggs. Quantitative gel-shift measurements are utilized to estimate minimum numbers of factor molecules per embryo at 24 hr postfertilization, when the CyIIIa gene is active, at 7 hr, when it is still silent, and in the unfertilized egg. We also estimate the binding affinity preferences (K_r) of the various factors for their respective sites, relative to their affinity for synthetic DNA competitors. At least 14 different specific interactions occur within the regulatory regions, some of which produce multiple DNA-protein complexes. Values of K_r range from approximately 2 x 10^4 to approximately 2 x 10^6 for these factors under the conditions applied. With one exception, the minimum factor prevalences that we measured in the 400-cell 24-hr embryo nuclear extracts fell within the range of 2 x 10^5 to 2 x 10^6 molecules per embryo, i.e., a few hundred to a few thousand molecules per nucleus. Three developmental patterns were observed with respect to factor prevalence: Factors reacting at one site were found in unfertilized egg cytoplasm at about the same level per egg or embryo as in 24-hr embryo nuclei; factors reacting with five other regions of the regulatory domain are not detectable in egg cytoplasm but in 7-hr mid-cleavage-stage embryo, nuclei are already at or close to their concentrations in the 24-hr embryo nuclei; and factors reacting with five additional regions are not detectable in egg cytoplasm and are low in 7-hr embryo nuclei, i.e., ⩽10% per embryo of the level they attain in 24-hr embryo nuclei. The rise in concentration of factors of the latter class could provide the proximal cause for the temporal activation of the CyIIIa gene at the early blastula stage
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