14 research outputs found
Effects of Resistance Training Status on Exercise Patterns and Body Composition Among Younger and Older Adults
As individuals age, percent body fat tends to increase and lean muscle mass decreases, which may limit the ability to engage in higher intensity exercise. Moderate to vigorous physical activity has been shown to improve body composition, but it is unclear whether exercise patterns, such as amount of moderate and high intensity exercise performed, are impacted by resistance training status in younger and older adults. PURPOSE: To examine whether resistance trained and untrained younger and older adults differ on duration of high, moderate, and low intensity exercise and percent body fat (%BF). METHODS: Younger (23.8 ± 0.4 years) and older (68.5 ± 1.2 years) healthy adults were categorized into 4 groups based on resistance training status: young resistance trained (YT: n = 22), young not resistance trained (YNT: n = 16), old resistance trained (OT: n = 17), and old not resistance trained (ONT: n = 20). Resistance trained participants had been training ≥ 2X per week, for the past ≥ 6 months. Participants completed a survey to assess the intensity and duration of exercise, and a dual x-ray absorptiometry (DEXA) scan was used to determine %BF. The survey asked how many minutes/hours per week participants engaged in high intensity exercise (e.g., jogging, hiking), moderate intensity exercise (e.g., light bicycling, walking briskly), and low intensity exercise (e.g., slow walking, easy yoga). Responses were coded as 1 = none, 2 = 30-60 minutes, 3 = 1-2 hours, 4 = 2-3 hours, 5 = 3-5 hours, and 6 = more than 5 hours. ANOVAs were used to determine group differences for each variable, p ≤ 0.05. Data are reported as mean ± SE. RESULTS: Group differences emerged for high and moderate intensity exercise (p \u3c 0.05), but not for low intensity (p \u3e 0.05). For high intensity, YT (3.64 ± 0.31) was significantly higher than YNT and ONT (YNT: 1.63 ± 0.37, p \u3c 0.001; ONT: 1.55 ± 0.33, p \u3c 0.001), and OT (2.82 ± 0.36) was significantly higher than YNT and ONT (YNT: p = 0.022; ONT: p = 0.010). For moderate intensity, YT (4.91 ± 0.31) was significantly higher than YNT and ONT (YNT: 2.40 ± 0.38, p \u3c 0.001; ONT: 3.52 ± 0.32, p = 0.003), and OT (4.77 ± 0.35) was significantly greater than YNT and ONT (YNT: p \u3c 0.001; ONT: p = 0.011). Also for moderate intensity, ONT was significantly greater than YNT (p = 0.025). For %BF, YT (25.06 ± 2.1%) was significantly lower than YNT and ONT (YNT: 33.55 ± 1.87%, p = 0.001; ONT: 36.47 ± 1.28%, p \u3c 0.001), and OT (29.37 ± 1.11%) was significantly lower than ONT (p = 0.003). All other group comparisons were not different (p \u3e 0.05). CONCLUSION: The older resistance trained individuals did not differ from the younger trained participants on exercise patterns or percent body fat, suggesting the enduring positive effects of resistance training as individuals age. These resistance trained individuals also performed more moderate and high intensity exercise than non-resistance trained groups, likely contributing to their favorable body composition. Funded by Texas American College of Sports Medicine Student Research Development Award to H. Kendall, J. Mettler, and L. Kipp, and Thesis Fellowship Award to H. Kendall
Effects of Neuromuscular Electrical Stimulation Training on Skeletal Muscle Anabolic Signaling in Older Adults
Neuromuscular electrical stimulation (NMES) generates involuntary muscle contraction and may be a safe and effective alternative to voluntary resistance training, which is important for those who cannot perform voluntary exercise due to age-related conditions. However, further research is needed to better understand the skeletal muscle anabolic signaling response of the mTORC1 (mammalian target of rapamycin complex 1) pathway with repeated bouts of NMES. PURPOSE: To determine changes in skeletal muscle anabolic signaling in response to a 4-week NMES intervention in older adults. METHODS: Participants (n = 7) in this clinical trial were healthy, older adults (70.4 ± 2.9 years). NMES was applied to the quadriceps muscles for 40 min/treatment, 3x/week for 4 weeks (12 sessions). On Day 1 and Day 12 of the NMES intervention, skeletal muscle biopsies were obtained from the vastus lateralis Pre-NMES and 30 minutes Post-NMES and were analyzed for phosphorylation of mammalian target of rapamycin (mTOR) and p70-S6 Kinase 1 (S6K1) anabolic signaling proteins using the SDS-PAGE Western blot technique. Phosphorylation is expressed as the ratio of phosphorylated to total protein content. Data were analyzed using paired t-tests and data are reported as mean ± SE with statistical significance set at p ≤ 0.05. RESULTS: On Day 1, phosphorylation of S6K1 increased (Pre-NMES: 0.652 ± 0.145 AU vs. Post-NMES: 0.979 ± 0.151 AU, p = 0.037) and phosphorylation of mTOR increased (Pre-NMES: 0.464 ± 0.077 AU vs. Post-NMES: 1.046 ± 0.128 AU, p = 0.006) from Pre-NMES to Post-NMES. On Day 12, phosphorylation of S6K1 increased (Pre-NMES: 0.628 ± 0.108 AU vs. Post-NMES: 1.253 ± 0.288 AU, p = 0.048) with an increasing trend for mTOR (Pre-NMES: 0.485 ± 0.044 AU vs. Post-NMES: 0.700 ± 0.154 AU, p = 0.053) from Pre-NMES to Post-NMES. Phosphorylated S6K1 and mTOR protein content were not different between Day 1 and Day 12 at Pre-NMES (p \u3e 0.05) or at Post-NMES (p \u3e 0.05). CONCLUSION: The findings of this study suggest that the anabolic signaling response to a bout of NMES remains upregulated after 4-weeks of treatment; thus, the response is not attenuated with short-term repeated bouts of NMES. Funding: Research Enhancement Program Grant to J Mettler and L Kipp; Research Accelerator Grant, Texas State University, to J Mettler
The Use of an Anti-CD40 Agonist Monoclonal Antibody During Immunizations Enhances Hybridoma Generation
Expression in Transgenic Mice of Dominant Interfering Fas Mutations: A Model for Human Autoimmune Lymphoproliferative Syndrome
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State of the California Current Ecosystem in 2021: Winter is coming?
In late 2020, models predicted that a strong La Niña would take place for the first time since 2013, and we assessed whether physical and biological indicators in 2021 were similar to past La Niñas in the California Current Ecosystem (CCE). The Pacific Decadal Oscillation and Oceanic Niño Index indeed remained negative throughout 2021; the North Pacific Gyre Oscillation Index, however, remained strongly negative. The seventh largest marine heatwave on record was unexpectedly present from April to the end of 2021; however, similar to past La Niñas, this mass of warm water mostly remained seaward of the continental shelf. As expected from past La Niñas, upwelling and chlorophyll were mostly high and sea surface temperature was low throughout the CCE; however, values were close to average south of Point Conception. Similar to past La Niñas, abundances of lipid-rich, northern copepods off Oregon increased. In northern California, unlike past La Niñas, the body size of North Pacific krill (Euphausia pacifica) was close to average. Predictably, overall krill abundance was above average in far northern California but, unexpectedly, below average south of Cape Mendocino. Off Oregon, similar to past La Niñas, larval abundances of three of six coastal species rose, while five of six southern/offshore taxa decreased in 2021. Off California, as expected based on 2020, Northern Anchovy (Engraulis mordax) were very abundant, while Pacific Sardine (Sardinops sagax) were low. Similar to past La Niñas, market squid (Doryteuthis opalescens) and young of the year (YOY) Pacific Hake (Merluccius pacificus), YOY sanddabs (Citharichthys spp.), and YOY rockfishes (Sebastes spp.) increased. Southern mesopelagic (e.g., Panama lightfish Vinciguerria lucetia, Mexican lampfish Triphoturus mexicanus) larvae decreased as expected but were still well above average, while northern mesopelagic (e.g., northern lampfish Stenobrachius leucopsarus) larvae increased but were still below average. In line with predictions, most monitored bird species had above-average reproduction in Oregon and California. California sea lion (Zalophus californianus) pup count, growth, and weight were high given the abundant Anchovy forage. The CCE entered an enduring La Niña in 2021, and assessing the responses of various ecosystem components helped articulate aspects of the system that are well understood and those that need further study
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Corrigendum: State of the California Current 2019–2020: Back to the Future With Marine Heatwaves?
State of the California Current 2019–2020: Back to the Future With Marine Heatwaves?
The California Current System (CCS) has experienced large fluctuations in environmental conditions in recent years that have dramatically affected the biological community. Here we synthesize remotely sensed, hydrographic, and biological survey data from throughout the CCS in 2019–2020 to evaluate how recent changes in environmental conditions have affected community dynamics at multiple trophic levels. A marine heatwave formed in the north Pacific in 2019 and reached the second greatest area ever recorded by the end of summer 2020. However, high atmospheric pressure in early 2020 drove relatively strong Ekman-driven coastal upwelling in the northern portion of the CCS and warm temperature anomalies remained far offshore. Upwelling and cooler temperatures in the northern CCS created relatively productive conditions in which the biomass of lipid-rich copepod species increased, adult krill size increased, and several seabird species experienced positive reproductive success. Despite these conditions, the composition of the fish community in the northern CCS remained a mixture of both warm- and cool-water-associated species. In the southern CCS, ocean temperatures remained above average for the seventh consecutive year. Abundances of juvenile fish species associated with productive conditions were relatively low, and the ichthyoplankton community was dominated by a mixture of oceanic warm-water and cosmopolitan species. Seabird species associated with warm water also occurred at greater densities than cool-water species in the southern CCS. The population of northern anchovy, which has been resurgent since 2017, continued to provide an important forage base for piscivorous fishes, offshore colonies of seabirds, and marine mammals throughout the CCS. Coastal upwelling in the north, and a longer-term trend in warming in the south, appeared to be controlling the community to a much greater extent than the marine heatwave itself
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State of the California Current Ecosystem report in 2022: a tale of two La Niñas
2022 marked the third consecutive La Niña and extended the longest consecutive stretch of negative Oceanic Niño Index since 1998-2001. While physical and biological conditions in winter and spring largely adhered to prior La Niña conditions, summer and fall were very different. Similar to past La Niña events, in winter and spring coastal upwelling was either average or above average, temperature average or below average, salinity generally above average. In summer and fall, however, upwelling and temperature were generally average or slightly below average, salinity was close to average and chlorophyll a was close to average. Again, as during prior La Niña events, biomass of northern/southern copepods was above/below average off Oregon in winter, and body size of North Pacific krill in northern California was above average in winter. By contrast, later in the year the abundance of northern krill dropped off Oregon while southern copepods increased and body sizes of North Pacific krill fell in northern California. Off Oregon and Washington abundances of market squid and Pacific pompano (indicators of warm, non-typical La Niña conditions) were high. In the 20th century, Northern anchovy recruitment tended to be high during cold conditions, but despite mostly warm conditions from 2015-2021 anchovy populations boomed and remained high in 2022. Resident seabird reproductive success, which tended in the past to increase during productive La Niña conditions was highly variable throughout the system as common murre and pelagic cormorant, experienced complete reproductive failure at Yaquina Head, Oregon while Brandt’s cormorant reproduction was average. At three sampling locations off central California, however, common murre reproduction was close to or above average while both pelagic and Brandt’s cormorant were above average. California sealion reproduction has been above average each year since 2016, and pup weight was also above average in 2022, likely in response not to La Niña or El Niño but continuous high abundance of anchovy. The highly variable and often unpredictable physical and biological conditions in 2022 highlight a growing recognition of disconnects between basin-scale indices and local conditions in the CCE. “July-December 2022 is the biggest outlier from individual “strong” La Niña (events) ever going back to the 50s.” – Nate Mantu