Abstract
Background
sarcopenia in ageing is a progressive decrease in muscle mass, strength and/or physical function. This review aims to summarise the definitions of sarcopenia in community-dwelling ...older adults and explore similarities and differences in prevalence estimates by definition.
Methods
a systematic review was conducted to identify articles which estimated sarcopenia prevalence in older populations using search terms for sarcopenia and muscle mass. Overall prevalence for each sarcopenia definition was estimated stratified by sex and ethnicity. Secondary analyses explored differences between studies and within definitions, including participant age, muscle mass measurement techniques and thresholds for muscle mass and gait speed.
Results
in 109 included articles, eight definitions of sarcopenia were identified. The lowest pooled prevalence estimates came from the European Working Group on Sarcopenia/Asian Working Group on Sarcopenia (12.9%, 95% confidence interval: 9.9–15.9%), International Working Group on Sarcopenia (9.9%, 3.2–16.6%) and Foundation for the National Institutes of Health (18.6%, 11.8–25.5%) definitions. The highest prevalence estimates were for the appendicular lean mass (ALM)/weight (40.4%, 19.5–61.2%), ALM/height (30.4%, 20.4–40.3%), ALM regressed on height and weight (30.4%, 20.4–40.3%) and ALM / body mass index (24.2%, 18.3–30.1%) definitions. Within definitions, the age of study participants and the muscle mass cut points used were substantive sources of between-study differences.
Conclusion
estimates of sarcopenia prevalence vary from 9.9 to 40.4%, depending on the definition used. Significant differences in prevalence exist within definitions across populations. This lack of agreement between definitions needs to be better understood before sarcopenia can be appropriately used in a clinical context.
ABSTRACTTo search for novel transcriptional pathways that are activated in skeletal muscle after endurance exercise, we used cDNA microarrays to measure global mRNA expression after an exhaustive ...bout of high‐intensity cycling (∼75 min). Healthy, young, sedentary males performed the cycling bout, and skeletal muscle biopsies were taken from the vastus lateralis before, and at 3 and 48 h after exercise. We examined mRNA expression in individual muscle samples from four subjects using cDNA microarrays, used repeated‐measures significance analysis of microarray (SAM) to determine statistically significant expression changes, and confirmed selected results using real‐time RT‐PCR. In total, the expression of 118 genes significantly increased 3 h postcycling and 8 decreased. At 48 h, the expression of 29 genes significantly increased and 5 decreased. Many of these are potentially important novel genes involved in exercise recovery and adaptation, including several involved in 1) metabolism and mitochondrial biogenesis (FOXO1, PPARδ, PPARγ, nuclear receptor binding protein 2, IL‐6 receptor, ribosomal protein L2, aminolevulinate δ‐synthase 2); 2) the oxidant stress response (metalothioneins 1B, 1F, 1G, 1H, 1L, 2A, 3, interferon regulatory factor 1); and 3) electrolyte transport across membranes Na+‐K+‐ATPase (β3), SERCA3, chloride channel 4. Others include genes involved in cell stress, proteolysis, apoptosis, growth, differentiation, and transcriptional activation, as well as all three nuclear receptor subfamily 4A family members (Nur77, Nurr1, and Nor1). This study is the first to characterize global mRNA expression during recovery from endurance exercise, and the results provide potential insight into 1) the transcriptional contributions to homeostatic recovery in human skeletal muscle after endurance exercise, and 2) the transcriptional contributions from a single bout of endurance exercise to the adaptive processes that occur after a period of endurance exercise training.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
Aim
A dysregulation of satellite cells may contribute to the progressive loss of muscle mass that occurs with age; however, older adults retain the ability to activate and expand their satellite cell ...pool in response to exercise. The modality of exercise capable of inducing the greatest acute response is unknown. We sought to characterize the acute satellite cell response following different modes of exercise in older adults.
Methods
Sedentary older men (n = 22; 67 ± 4 years; 27 ± 2.6 kg*m−2) were randomly assigned to complete an acute bout of either resistance exercise, high‐intensity interval exercise on a cycle ergometer or moderate‐intensity aerobic exercise. Muscle biopsies were obtained before, 24 and 48 h following each exercise bout. The satellite cell response was analysed using immunofluorescent microscopy of muscle cross sections.
Results
Satellite cell expansion associated with type I fibres was observed 24 and 48 h following resistance exercise only (P ˂ 0.05), while no expansion of type II‐associated satellite cells was observed in any group. There was a greater number of activated satellite cells 24 h following resistance exercise (pre: 1.3 ± 0.1, 24 h: 4.8 ± 0.5 Pax7 + /MyoD+cells/100 fibres) and high‐intensity interval exercise (pre: 0.7 ± 0.3, 24 h: 3.1 ± 0.3 Pax7 + /MyoD+cells/100 fibres) (P ˂ 0.05). The percentage of type I‐associated SC co‐expressing MSTN was reduced only in the RE group 24 h following exercise (pre: 87 ± 4, 24 h: 57 ± 5%MSTN+ type I SC) (P < 0.001).
Conclusion
Although resistance exercise is the most potent exercise type to induce satellite cell pool expansion, high‐intensity interval exercise was also more potent than moderate‐intensity aerobic exercise in inducing satellite cell activity.
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DOBA, FSPLJ, FZAB, GIS, IJS, IZUM, KILJ, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBMB, SIK, UILJ, UKNU, UL, UM, UPUK
We present a new approach that demonstrates the deflection and guiding of relativistic electron beams over curved paths by means of the magnetic field generated in a plasma-discharge capillary. We ...experimentally prove that the guiding is much less affected by the beam chromatic dispersion with respect to a conventional bending magnet and, with the support of numerical simulations, we show that it can even be made dispersionless by employing larger discharge currents. This proof-of-principle experiment extends the use of plasma-based devices, that revolutionized the field of particle accelerators enabling the generation of GeV beams in few centimeters. Compared to state-of-the-art technology based on conventional bending magnets and quadrupole lenses, these results provide a compact and affordable solution for the development of next-generation tabletop facilities.
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CMK, CTK, FMFMET, IJS, NUK, PNG, UL, UM
Abstract
The high longitudinal electric fields generated in plasma wakefields are very attractive for a new generation of high gradient plasma based accelerators. On the other hand, the strong ...transverse fields increase the demand for a proper matching device in order to avoid the spoiling of beam transverse quality. A solution can be provided by the use of a plasma ramp, a region at the plasma injection/extraction with smoothly increasing/decreasing plasma density. The transport of a beam inside a plasma ramp, beside its parameters, depends on the profile of the ramp itself. Establishing the transfer matrix for a plasma ramp represent a very useful tool in order to evaluate the beam evolution in the plasma. In this paper a study of a cosine squared ramp is presented. An approximate solution of the transverse equation of motion is evaluated and exploited to provide a simple transfer matrix for the plasma ramp. The transfer matrix is then employed to demonstrate that this kind of ramp has the effect to minimize the emittance growth due to betatron dephasing. The behavior of a squared cosine plasma ramp will be compared with an experimentally measured plasma ramp profile in order to validate the applicability of the transfer matrix to real cases.
Departments of 1 Medical Sciences, 2 Kinesiology, 4 Pediatrics and Medicine, McMaster University, Hamilton, Ontario, Canada; and 3 Buck Institute for Aging Research, Novato, California
Submitted 26 ...November 2007
; accepted in final form 28 February 2008
We used cDNA microarrays to screen for differentially expressed genes during recovery from exercise-induced muscle damage in humans. Male subjects ( n = 4) performed 300 maximal eccentric contractions, and skeletal muscle biopsy samples were analyzed at 3 h and 48 h after exercise. In total, 113 genes increased 3 h postexercise, and 34 decreased. At 48 h postexercise, 59 genes increased and 29 decreased. On the basis of these data, we chose 19 gene changes and conducted secondary analyses using real-time RT-PCR from muscle biopsy samples taken from 11 additional subjects who performed an identical bout of exercise. Real-time RT-PCR analyses confirmed that exercise-induced muscle damage led to a rapid (3 h) increase in sterol response element binding protein 2 ( SREBP-2 ), followed by a delayed (48 h) increase in the SREBP-2 gene targets Acyl CoA:cholesterol acyltransferase ( ACAT )-2 and insulin-induced gene 1 ( insig-1 ). The expression of the IL-1 receptor , a known regulator of SREBP-2, was also elevated after exercise. Taken together, these expression changes suggest a transcriptional program for increasing cholesterol and lipid synthesis and/or modification. Additionally, damaging exercise induced the expression of protein kinase H11 , capping protein Z alpha ( capZ ), and modulatory calcineurin-interacting protein 1 ( MCIP1 ), as well as cardiac ankryin repeat protein 1 ( CARP1 ), DNAJB2 , c-myc , and junD , each of which are likely involved in skeletal muscle growth, remodeling, and stress management. In summary, using DNA microarrays and RT-PCR, we have identified novel genes that respond to skeletal muscle damage, which, given the known biological functions, are likely involved in recovery from and/or adaptation to damaging exercise.
mRNA analysis; sterol response element binding protein
Address for reprint requests and other correspondence: M. A. Tarnopolsky, Dept. of Pediatrics, Rm. 4U4, McMaster Univ. Medical Center, 1200 Main St. W., Hamilton, Ontario, Canada, L8N 3Z5 (e-mail: tarnopol{at}mcmaster.ca )
The sessile lifestyle of plants exposes them to many challenges that must be overcome to ensure their survival. Despite their apparent lack of movement and behaviour, plants are very active organisms ...that constantly respond to external cues and internal signals, making fine tunings at the metabolic, cellular and tissue levels. To accomplish this, plants largely rely on their relationship between phenotypic plasticity and cognitive abilities, which requires an information (or signalling) system. This information system is composed of many different signals, and among them are the electrical ones. Besides, in plants, there are many electrical activities that are not necessarily considered electrical signals. However, the sum of all electrical activity of a plant, considering all levels of organization, engenders the electrical dimension of their life. This dimension of life that encompasses all the living beings has recently been named “electrome”, in analogy with the other ‘omics’ from system biology approach. In the present review, we will explore this concept to describe the plant electrical activities. Furthermore, some basic aspects that are underlying the plant electrome will be presented, including the principles of biophysics that sustain the electrical activity of the cells. Moreover, some examples of electrical activities and signals that are vital to the plants will be exposed. Then, our most relevant and recent breakthroughs about plant electrome dynamics under different environmental conditions will be presented. Finally, some considerations about the possible involvement of the electrome plasticity and cognition features associated with the adaptive behaviour of plants will be discussed.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OBVAL, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
The lung is the preferred site of metastasis from soft tissue sarcoma (STS). This systematic review aims to evaluate the outcomes of stereotactic body radiotherapy (SBRT) and metastasectomy (MTS) for ...the treatment of lung metastases from STS. A systematic review was carried out according to the PRISMA protocol. PubMed, Medline, EMBASE, Cochrane Library, Ovid and Web of Knowledge databases were searched for English-language articles to December 2018 using a predefined strategy. Retrieved studies were independently screened and rated for relevance. Data were extracted by two researchers. In total, there were 1306 patients with STS: 1104 underwent MTS and 202 had SBRT. The mean age ranged from 40 to 55.8 years in the MTS group and from 47.9 to 64 years in the SBRT group. The cumulative death rate was 72% (95% confidence interval 59–85%) in the MTS group and 56% (38–74%) in the SBRT group. The cumulative mean overall survival time was 46.7 months (36.4–57.0%) in the MTS group and 47.6 months (33.7–61.5%) in the SBRT group. The cumulative rate of patients alive with disease was 5% (2–9%) in the MTS group and 15% (6–36%) in the SBRT group. Finally, the cumulative rate of patients alive without disease in the two groups was 19% (9–29%) and 20% (10–50%), respectively. Our study showed that local treatment of pulmonary metastases from STS with SBRT, compared with surgery, was associated with a lower cumulative overall death rate and similar overall survival time and survival rates without disease. By contrast, SBRT was associated with a higher survival rate with disease than MTS. Large randomised trials are necessary to confirm these findings and to establish whether SBRT may be a reliable option for early stage disease.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Abstract
The SPARC_LAB test facility at the LNF (Laboratori Nazionali di Frascati, Rome) holds a high brightness photo-injector used to investigate advanced beam manipulation techniques. High ...brightness electron bunch trains (so-called comb beams) can be generated striking on the photo-cathode of a Radio Frequency (RF) photo-injector with a ultra-short UV laser pulse train in tandem with the velocity bunching technique. Beam dynamics studies have been performed with the aim of optimizing the dynamics of the double beam (driver and witness) used to perform particle driven plasma wake field acceleration (PWFA). In this scenario different scans on beam parameters were carried on adopting the ASTRA simulation code, in order to optimize the witness beam quality and improve the plasma booster stage performances. A benchmark of the simulations has been then performed, reproducing the experimental data obtained from the optimization of machine performances, and a good agreement was found.
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