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  • 101.
    Stoeggl, Thomas L.
    et al.
    Univ Salzburg, Dept Sport & Exercise Sci, Salzburg, Austria.;Red Bull Athlete Performance Ctr, Salzburg, Austria..
    Hertlein, Markus
    Univ Salzburg, Dept Sport & Exercise Sci, Salzburg, Austria..
    Brunauer, Richard
    Salzburg Res Forschungsgesell MbH, Salzburg, Austria..
    Welde, Boye
    UiT Arctic Univ Norway, Sch Sport Sci, Tromso, Norway..
    Andersson, Erik P.
    Mittuniversitetet, Fakulteten för humanvetenskap, Institutionen för hälsovetenskap.
    Swaren, Mikael
    Swedish Olymp Acad, Stockholm, Sweden.;Dalarna Univ, Dept Sports Fitness & Med, Falun, Sweden..
    Pacing, Exercise Intensity, and Technique by Performance Level in Long-Distance Cross-Country Skiing2020Ingår i: Frontiers in Physiology, ISSN 1664-042X, E-ISSN 1664-042X, Vol. 11, artikel-id 17Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Introduction Long-distance cross-country skiing (XCS) has gained increased popularity within the past decades. However, research about long-distance XCS is limited; therefore, the aim of this study was to analyze the intensity distribution, technique application, and pacing strategies during long-distance XCS racing. Methods Heart rate (HR) and section skiing speeds of 9 elite (ranked 1-100) and 10 amateur skiers (ranked 101-1,500) during the 90-km Vasaloppet race were collected. In addition, during the first uphill, the first 1,000 skiers were video-recorded to analyze the applied skiing strategy (e.g. grip-waxed skis versus exclusive double poling). Results Mean race intensity was 82% of maximal HR and was not different between performance groups even though elite skiers skied similar to 15% faster than amateurs. There was an interaction effect of section x group with a pronounced decrease in HR in amateurs compared with more even pacing in elite skiers (0.13 vs. 0.04% decrease/km) and skiing at higher percentage in the high-intensity zones in elite compared with amateurs (46 vs. 24%). Ninety-eight percent of the top 100 skiers and 59% of the first 1,000 skiers used exclusively double poling. Conclusion Elite and amateur skiers ski at comparable mean race exercise intensity, but they have clear differences in skiing speed. The difference in the pacing profiles between elite and amateur skiers (more even vs. distinct positive pacing) demonstrate the greater capacity of the former with respect to physiological capacity and highlights that amateurs seem to start too fast according to their capacities. The exclusive application of the double poling technique is no longer a phenomenon of elite skiers but is widely used among the top 1,000 ranked skiers.

  • 102. Stöggl, T. L.
    et al.
    Hertlein, M.
    Brunauer, R.
    Welde, B.
    Andersson, E. P.
    Swarén, Mikael
    Högskolan Dalarna, Akademin Utbildning, hälsa och samhälle, Idrotts- och hälsovetenskap. Swedish Olympic Academy, Stockholm.
    Pacing, Exercise Intensity, and Technique by Performance Level in Long-Distance Cross-Country Skiing2020Ingår i: Frontiers in Physiology, ISSN 1664-042X, E-ISSN 1664-042X, Vol. 11, artikel-id 17Artikel i tidskrift (Refereegranskat)
  • 103.
    Stöggl, Thomas
    et al.
    University of Salzburg, Salzburg, Austria.
    Björklund, Glenn
    Mittuniversitetet, Fakulteten för humanvetenskap, Avdelningen för hälsovetenskap. The Swedish Sports Confederation, Stockholm, Sweden.
    High intensity interval training leads to greater improvements in acute heart rate recovery and anaerobic power as high volume low intensity training2017Ingår i: Frontiers in Physiology, ISSN 1664-042X, E-ISSN 1664-042X, Vol. 8, artikel-id 562Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The purpose of the current study was to explore if training regimes utilizing diverse training intensity distributions result in different responses on neuromuscular status, anaerobic capacity/power and acute heart rate recovery (HRR) in well-trained endurance athletes.

    Methods: Thirty-six male (n = 33) and female (n = 3) runners, cyclists, triathletes and cross-country skiers [peak oxygen uptake: (VO2peak): 61.9 ± 8.0 mL·kg−1·min−1] were randomly assigned to one of three groups (blocked high intensity interval training HIIT; polarized training POL; high volume low intensity oriented control group CG/HVLIT applying no HIIT). A maximal anaerobic running/cycling test (MART/MACT) was performed prior to and following a 9-week training period.

    Results: Only the HIIT group achieved improvements in peak power/velocity (+6.4%, P < 0.001) and peak lactate (P = 0.001) during the MART/MACT, while, unexpectedly, in none of the groups the performance at the established lactate concentrations (4, 6, 10 mmol·L−1) was changed (P > 0.05). Acute HRR was improved in HIIT (11.2%, P = 0.002) and POL (7.9%, P = 0.023) with no change in the HVLIT oriented control group.

    Conclusion: Only a training regime that includes a significant amount of HIIT improves the neuromuscular status, anaerobic power and the acute HRR in well-trained endurance athletes. A training regime that followed more a low and moderate intensity oriented model (CG/HVLIT) had no effect on any performance or HRR outcomes.

  • 104.
    Stöggl, Thomas
    et al.
    Mittuniversitetet, Fakulteten för humanvetenskap, Avdelningen för hälsovetenskap. Department of Sport Science and Kinesiology, University of Salzburg, Salzburg, Austria .
    Sperlich, B.
    Institute of Sport Science, University of Würzburg, Würzburg, Germany .
    Polarized training has greater impact on key endurance variables than threshold, high intensity, or high volume training2014Ingår i: Frontiers in Physiology, ISSN 1664-042X, E-ISSN 1664-042X, Vol. 5, s. Art. no. 33-Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Endurance athletes integrate four conditioning concepts in their training programs: high-volume training (HVT), "threshold-training" (THR), high-intensity interval training (HIIT) and a combination of these aforementioned concepts known as polarized training (POL). The purpose of this study was to explore which of these four training concepts provides the greatest response on key components of endurance performance in well-trained endurance athletes. Methods: Forty eight runners, cyclists, triathletes, and cross-country skiers (peak oxygen uptake: (VO2peak): 62.6 ± 7.1 mL·min-1·kg-1) were randomly assigned to one of four groups performing over 9 weeks. An incremental test, work economy and a VO2peak tests were performed. Training intensity was heart rate controlled. Results: POL demonstrated the greatest increase in VO2peak (+6.8 ml·min·kg-1 or 11.7%, P &lt; 0.001), time to exhaustion during the ramp protocol (+17.4%, P &lt; 0.001) and peak velocity/power (+5.1%, P &lt; 0.01). Velocity/power at 4 mmol·L-1 increased after POL (+8.1%, P &lt; 0.01) and HIIT (+5.6%, P &lt; 0.05). No differences in pre- to post-changes of work economy were found between the groups. Body mass was reduced by 3.7% (P &lt; 0.001) following HIIT, with no changes in the other groups. With the exception of slight improvements in work economy in THR, both HVT and THR had no further effects on measured variables of endurance performance (P &gt; 0.05). Conclusion: POL resulted in the greatest improvements in most key variables of endurance performance in well-trained endurance athletes. THR or HVT did not lead to further improvements in performance related variables. © 2014 Stöggl and Sperlich.

  • 105.
    Supej, Matej
    et al.
    Univ Ljubljana, Ljubljana, Slovenia.
    Holmberg, Hans-Christer
    Mittuniversitetet, Fakulteten för humanvetenskap, Institutionen för hälsovetenskap. UiT Arctic Univ Norway, Tromso, Norway.
    Recent Kinematic and Kinetic Advances in Olympic Alpine Skiing: Pyeongchang and Beyond2019Ingår i: Frontiers in Physiology, ISSN 1664-042X, E-ISSN 1664-042X, Vol. 10, nr FEB, artikel-id 111Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Alpine skiing has been an Olympic event since the first Winter Games in 1936. Nowadays, skiers compete in four main events: slalom, giant slalom, super-G and downhill. Here, we present an update on the biomechanics of alpine ski racers and their equipment. The technical and tactical ability of today's world-class skiers have adapted substantially to changes in equipment, snow conditions and courses. The wide variety of terrain, slopes, gate setups and snow conditions involved in alpine skiing requires skiers to continuously adapt, alternating between the carving and skidding turning techniques. The technical complexity places a premium on minimizing energy dissipation, employing strategies and ski equipment that minimize ski-snow friction and aerodynamic drag. Access to multiple split times along the racing course, in combination with analysis of the trajectory and speed provide information that can be utilized to enhance performance. Peak ground reaction forces, which can be as high as five times body weight, serve as a measure of the external load on the skier and equipment. Although the biomechanics of alpine skiing have significantly improved, several questions concerning optimization of skiers' performance remain to be investigated. Recent advances in sensor technology that allow kinematics and kinetics to be monitored can provide detailed information about the biomechanical factors related to success in competitions. Moreover, collection of data during training and actual competitions will enhance the quality of guidelines for training future Olympic champions. At the same time, the need to individualize training and skiing equipment for each unique skier will motivate innovative scientific research for years to come.

  • 106.
    Turanli, Beste
    et al.
    KTH, Centra, Science for Life Laboratory, SciLifeLab. Istanbul Medeniyet Univ, Dept Bioengn, Istanbul, Turkey.;Marmara Univ, Dept Bioengn, Istanbul, Turkey..
    Grotli, Morten
    Univ Gothenburg, Dept Chem & Mol Biol, Gothenburg, Sweden..
    Boren, Jan
    Univ Gothenburg, Sahlgrenska Univ Hosp, Dept Mol & Clin Med, Gothenburg, Sweden..
    Nielsen, Jens
    Chalmers Univ Technol, Dept Biol & Biol Engn, Gothenburg, Sweden..
    Uhlén, Mathias
    KTH, Centra, Science for Life Laboratory, SciLifeLab.
    Arga, Kazim Y.
    Marmara Univ, Dept Bioengn, Istanbul, Turkey..
    Mardinoglu, Adil
    KTH, Centra, Science for Life Laboratory, SciLifeLab. Chalmers Univ Technol, Dept Biol & Biol Engn, Gothenburg, Sweden..
    Drug Repositioning for Effective Prostate Cancer Treatment2018Ingår i: Frontiers in Physiology, ISSN 1664-042X, E-ISSN 1664-042X, Vol. 9, artikel-id 500Artikel, forskningsöversikt (Refereegranskat)
    Abstract [en]

    Drug repositioning has gained attention from both academia and pharmaceutical companies as an auxiliary process to conventional drug discovery. Chemotherapeutic agents have notorious adverse effects that drastically reduce the life quality of cancer patients so drug repositioning is a promising strategy to identify non-cancer drugs which have anti-cancer activity as well as tolerable adverse effects for human health. There are various strategies for discovery and validation of repurposed drugs. In this review, 25 repurposed drug candidates are presented as result of different strategies, 15 of which are already under clinical investigation for treatment of prostate cancer (PCa). To date, zoledronic acid is the only repurposed, clinically used, and approved non-cancer drug for PCa. Anti-cancer activities of existing drugs presented in this review cover diverse and also known mechanisms such as inhibition of mTOR and VEGFR2 signaling, inhibition of PI3K/Akt signaling, COX and selective COX-2 inhibition, NF-kappa B inhibition, Wnt/beta - Catenin pathway inhibition, DNMT1 inhibition, and GSK-3 beta inhibition. In addition to monotherapy option, combination therapy with current anti-cancer drugs may also increase drug efficacy and reduce adverse effects. Thus, drug repositioning may become a key approach for drug discovery in terms of time- and cost-efficiency comparing to conventional drug discovery and development process.

  • 107.
    Verschut, Thomas A.
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen, Avdelningen för funktionell zoomorfologi.
    Farnier, Kevin
    Cunningham, J. Paul
    Carlsson, Mikael A.
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen, Avdelningen för funktionell zoomorfologi.
    Behavioral and Physiological Evidence for Palp Detection of the Male-Specific Attractant Cuelure in the Queensland Fruit Fly (Bactrocera tryoni)2018Ingår i: Frontiers in Physiology, ISSN 1664-042X, E-ISSN 1664-042X, Vol. 9, artikel-id 990Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The Queensland fruit fly, Bactrocera tryoni, is considered one of the worst horticultural pests in Australia attacking a large variety of fruit crops. To defeat pest insects, olfactory attractants have been developed and widely used in lure and kill strategies. Male B. tryoni are strongly attracted to the compound raspberry ketone and its synthetic analog, cuelure. Despite the strong behavioral response, a recent study failed to show any activation of antennal receptors to cuelure. Therefore, we hypothesized that cuelure may be detected by an accessory olfactory organ, the maxillary palp. Combining behavioral and physiological experiments we clearly demonstrate that male flies, but not female flies, primarily use the maxillary palps and not the antennae to detect and respond to cuelure. Furthermore, regardless of satiety status, male flies always preferred cuelure over a sugar rich source, unless the maxillary palps were excised.

  • 108.
    Wang, Jun
    et al.
    The Belt and Road Joint Laboratory for Winter Sports, Department of Exercise Physiology, Beijing Sport University, Beijing, ChinaBeijing Sport Univ, Dept Exercise Physiol, Belt & Rd Joint Lab Winter Sports, Beijing, Peoples R China..
    Ji, Yunhui
    Department of Physical Education, Shanxi Medical University, Taiyuan, China.
    Zhou, Li
    The Belt and Road Joint Laboratory for Winter Sports, Department of Exercise Physiology, Beijing Sport University, Beijing, China.
    Xiang, Yang
    School of Physical Education, Yan’an University, Yan’an, China.
    Heinonen, Ilkka
    Högskolan i Halmstad, Akademin för ekonomi, teknik och naturvetenskap, Rydberglaboratoriet för tillämpad naturvetenskap (RLAS). Turku PET Centre, Department of Clinical Physiology and Nuclear Medicine, University of Turku, Turku, Finland.
    Zhang, Peng
    Department of Exercise Science, East Stroudsburg University of Pennsylvania, East Stroudsburg, PA, United States.
    A New Method to Improve Running Economy and Maximal Aerobic Power in Athletes: Endurance Training With Periodic Carbon Monoxide Inhalation2019Ingår i: Frontiers in Physiology, ISSN 1664-042X, E-ISSN 1664-042X, Vol. 10, artikel-id 701Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Background: Altitude training stimulates erythropoietin hormone (EPO) release and increases blood hemoglobin (Hb) mass, which may result in improved oxygen (O-2) transport capacity. It was hypothesized in the present study that periodic inhalation of carbon monoxide (CO) might elicit similar physiological adaptations compared to altitude training.

    Methods: Twelve male college student athletes, who were well-trained soccer players, participated. They performed a 4-week treadmill-training program, five times a week. Participants were randomly assigned into an experimental group with inhaling CO (INCO) (1 mL/kg body weight for 2 min) in O-2 (4 L) before all training sessions and a control group without inhaling CO (NOCO). CO and EPO concentrations in venous blood were first measured acutely at the 1st, 2nd, 4th, 6th, and 8th hour after INCO, and total hemoglobin mass (tHb), running economy and VO(2)max were measured before and after the 4 weeks training intervention.

    Results: HbCO% increased from 0.7 to 4.4% (P < 0.05) after 1 h of CO inhalation and EPO increased from 1.9 to 2.7 mIU/mL after 4 h post CO inhalation (P < 0.05) acutely before the intervention. After the training, the tHb and VO(2)max in the INCO group increased significantly by 3.7 and 2.7%, respectively, while no significant differences were observed in the NOCO condition. O-2 uptake at given submaximal speeds declined by approximately 4% in the INCO group.

    Conclusion: Acutely, EPO increased sharply post CO inhalation, peaking at 4 h post inhalation. 4-weeks of training with CO inhalation before exercise sessions improved tHb and VO(2)max as well as running economy, suggesting that moderate CO inhalation could be a new method to improve the endurance performance in athletes. © 2019 Frontiers Media S.A. All Rights Reserved.

  • 109.
    Widing, Carl Hannes
    et al.
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för kirurgiska vetenskaper, Anestesiologi och intensivvård. Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för kirurgiska vetenskaper, Hedenstiernalaboratoriet. NU Hosp Org, Trollhattan, Sweden.
    Pellegrini, Mariangela
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för kirurgiska vetenskaper, Hedenstiernalaboratoriet. Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för kirurgiska vetenskaper, Anestesiologi och intensivvård. Uppsala Univ Hosp, Dept Anaesthesia & Intens Care Med, Uppsala, Sweden.
    Larsson, Anders
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för kirurgiska vetenskaper, Anestesiologi och intensivvård. Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för kirurgiska vetenskaper, Hedenstiernalaboratoriet. Uppsala Univ Hosp, Dept Anaesthesia & Intens Care Med, Uppsala, Sweden.
    Perchiazzi, Gaetano
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för kirurgiska vetenskaper, Hedenstiernalaboratoriet. Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för kirurgiska vetenskaper, Anestesiologi och intensivvård. Uppsala Univ Hosp, Dept Anaesthesia & Intens Care Med, Uppsala, Sweden.
    The Effects of Positive End-Expiratory Pressure on Transpulmonary Pressure and Recruitment-Derecruitment During Neurally Adjusted Ventilator Assist: A Continuous Computed Tomography Study in an Animal Model of Acute Respiratory Distress Syndrome2019Ingår i: Frontiers in Physiology, ISSN 1664-042X, E-ISSN 1664-042X, Vol. 10, artikel-id 1392Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Background Whether spontaneous breathing (SB) should be used in early acute respiratory distress syndrome (ARDS) is questioned because it may cause ventilator-induced lung injury (VILI) by tidal high strain/stress and recruitment/derecruitment (R/D). However, SB has shown beneficial effects when used appropriately. We hypothesized that high levels of positive end-expiratory pressure (PEEP), during assisted SB, would prevent tidal R/D, reducing ventilatory variation and respiratory rate while potentially increasing transpulmonary pressure (P-TP). The aim was to test this hypothesis in experimental mild ARDS during continuous SB using neurally adjusted ventilator assist (NAVA) and uninterrupted computed tomography (CT) exposure. Methods Mild experimental ARDS (PaO2/FiO2-ratio of 250) was induced in anesthetized pigs (n = 5), ventilated using uninterrupted NAVA. PEEP was changed in steps of 3 cmH(2)O, from 0 to 15 and back to 0 cmH(2)O. Dynamic CT scans, ventilatory parameters, and esophageal pressure were acquired simultaneously. P-TP and R/D were calculated and compared among PEEP levels. Results When increasing PEEP from 0 to 15 cmH(2)O, tidal R/D decreased from 4.3 +/- 5.9 to 1.1 +/- 0.7% (p < 0.01), breath-to-breath variability decreased, and P-TP increased from 11.4 +/- 3.7 to 29.7 +/- 14.1 cmH(2)O (R-2 = 0.96). Conclusion This study shows that injurious phenomena like R/D and high P-TP are present in NAVA at the two extremes of the PEEP spectrum. Willing to titrate PEEP to limit these phenomena, the physician must choose the best compromise between restraining the R/D or P-TP.

  • 110.
    Zanchi, Davide
    et al.
    Univ Basel Hosp, Dept Psychiat, Basel, Switzerland.
    Viallon, Magalie
    Univ Jean Monnet St Etienne, Univ Lyon, INSA Lyon, CNRS,UMR 5220,INSERM,U1206,CREATIS, St Etienne, France.; CHU St Etienne, Dept Radiol, St Etienne, France.
    Le Goff, Caroline
    Univ Liege, Dept Clin Chem, Liege, Belgium.
    Millet, Grégoire P
    Univ Lausanne, Inst Sports Sci, Lausanne, Switzerland.
    Giardini, Guido
    Department of Neurology and Stroke Unit, Mountain Medicine and Neurology Center Valle d'Aosta Regional Hospital, Aosta, Italy.
    Croisille, Pierre
    Univ Jean Monnet St Etienne, Univ Lyon, INSA Lyon, CNRS,UMR 5220,INSERM,U1206,CREATIS, St Etienne, France.; CHU St Etienne, Dept Radiol, St Etienne, France.
    Haller, Sven
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för kirurgiska vetenskaper, Radiologi. Affidea Ctr Diagnost Radiol Carouge CDRC, Geneva, Switzerland.; Univ Geneva, Fac Med, Geneva, Switzerland.; Univ Hosp Freiburg, Dept Neuroradiol, Freiburg, Germany.
    Extreme Mountain Ultra-Marathon Leads to Acute but Transient Increase in Cerebral Water Diffusivity and Plasma Biomarkers Levels Changes2017Ingår i: Frontiers in Physiology, ISSN 1664-042X, E-ISSN 1664-042X, Vol. 7, artikel-id 664Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Background: Pioneer studies demonstrate the impact of extreme sport load on the human brain, leading to threatening conditions for athlete's health such as cerebral edema. The investigation of brain water diffusivity, allowing the measurement of the intercellular water and the assessment of cerebral edema, can give a great contribution to the investigation of the effects of extreme sports on the brain. We therefore assessed the effect of supra-physiological effort (extreme distance and elevation changes) in mountain ultra-marathons (MUMs) athletes combining for the first time brain magnetic resonance imaging (MRI) and blood parameters.

    Methods:This longitudinal study included 19 volunteers (44.2 ± 9.5 years) finishing a MUM (330 km, elevation + 24000 m). Quantitative measurements of brain diffusion-weighted images (DWI) were performed at 3 time-points: Before the race, upon arrival and after 48 h. Multiple blood biomarkers were simultaneously investigated. Data analyses included brain apparent diffusion coefficient (ADC) and physiological data comparisons between three time-points.

    Results:The whole brain ADC significantly increased from baseline to arrival (p = 0.005) and then significantly decreased at recovery (p = 0.005) to lower values than at baseline (p = 0.005). While sodium, potassium, calcium, and chloride as well as hematocrit (HCT) changed over time, the serum osmolality remained constant. Significant correlations were found between whole brain ADC changes and osmolality (p = 0.01), cholesterol (p = 0.009), c-reactive protein (p = 0.04), sodium (p = 0.01), and chloride (p = 0.002) plasma level variations.

    Conclusions:These results suggest the relative increase of the inter-cellular volume upon arrival, and subsequently its reduction to lower values than at baseline, indicating that even after 48 h the brain has not fully recovered to its equilibrium state. Even though serum electrolytes may only indirectly indicate modifications at the brain level due to the blood brain barrier, the results concerning osmolality suggest that body water might directly influence the change in cerebral ADC. These findings establish therefore a direct link between general brain inter-cellular water content and physiological biomarkers modifications produced by extreme sport.

  • 111.
    Zhang, Cheng
    et al.
    KTH, Centra, Science for Life Laboratory, SciLifeLab.
    Bidkhori, Gholamreza
    KTH, Centra, Science for Life Laboratory, SciLifeLab.
    Benfeitas, Rui
    KTH, Centra, Science for Life Laboratory, SciLifeLab.
    Lee, Sunjae
    KTH, Centra, Science for Life Laboratory, SciLifeLab.
    Arif, Muhammad
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Proteinvetenskap, Systembiologi.
    Uhlen, Mathias
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Proteinvetenskap, Systembiologi.
    Mardinoglu, Adil
    KTH, Centra, Science for Life Laboratory, SciLifeLab.
    ESS: A Tool for Genome-Scale Quantification of Essentiality Score for Reaction/Genes in Constraint-Based Modeling2018Ingår i: Frontiers in Physiology, ISSN 1664-042X, E-ISSN 1664-042X, Vol. 9, artikel-id 1355Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Genome-scale metabolic models (GEMs) are comprehensive descriptions of cell metabolism and have been extensively used to understand biological responses in health and disease. One such application is in determining metabolic adaptation to the absence of a gene or reaction, i.e., essentiality analysis. However, current methods do not permit efficiently and accurately quantifying reaction/gene essentiality. Here, we present Essentiality Score Simulator (ESS), a tool for quantification of gene/reaction essentialities in GEMs. ESS quantifies and scores essentiality of each reaction/gene and their combinations based on the stoichiometric balance using synthetic lethal analysis. This method provides an option to weight metabolic models which currently rely mostly on topologic parameters, and is potentially useful to investigate the metabolic pathway differences between different organisms, cells, tissues, and/or diseases. We benchmarked the proposed method against multiple network topology parameters, and observed that our method displayed higher accuracy based on experimental evidence. In addition, we demonstrated its application in the wild-type and ldh knock-out E. coli core model, as well as two human cell lines, and revealed the changes of essentiality in metabolic pathways based on the reactions essentiality score. ESS is available without any limitation at https://sourceforge.net/projects/essentiality-score-simulator.

  • 112. Zhang, Cheng
    et al.
    Hua, Qiang
    Applications of Genome-Scale Metabolic Models in Biotechnology and Systems Medicine: Application of GEMs2016Ingår i: Frontiers in Physiology, ISSN 1664-042X, E-ISSN 1664-042X, Vol. 6, nr January, artikel-id 413Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Genome-scale metabolic models (GEMs) have become a popular tool for systems biology, and they have been used in many fields such as industrial biotechnology and systems medicine. Since more and more studies are being conducted using GEMs, they have recently received considerable attention. In this review, we introduce the basic concept of GEMs and provide an overview of their applications in biotechnology, systems medicine, and some other fields. In addition, we describe the general principle of the applications and analyses built on GEMs. The purpose of this review is to introduce the application of GEMs in biological analysis and to promote its wider use by biologists.

  • 113.
    Zhang, Cheng
    et al.
    KTH, Centra, Science for Life Laboratory, SciLifeLab.
    Lee, Sunjae
    KTH, Centra, Science for Life Laboratory, SciLifeLab.
    Mardinoglu, Adil
    KTH, Skolan för bioteknologi (BIO), Proteomik och nanobioteknologi. KTH, Centra, Science for Life Laboratory, SciLifeLab. Chalmers, Dept Biol & Biol Engn, Sweden.
    Hua, Qiang
    Investigating the Combinatory Effects of Biological Networks on Gene Co-expression2016Ingår i: Frontiers in Physiology, ISSN 1664-042X, E-ISSN 1664-042X, Vol. 7, artikel-id 160Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Co-expressed genes often share similar functions, and gene co-expression networks have been widely used in studying the functionality of gene modules. Previous analysis indicated that genes are more likely to be co-expressed if they are either regulated by the same transcription factors, forming protein complexes or sharing similar topological properties in protein-protein interaction networks. Here, we reconstructed transcriptional regulatory and protein-protein networks for Saccharornyces cerevisiae using well-established databases, and we evaluated their co-expression activities using publically available gene expression data. Based on our network-dependent analysis, we found that genes that were co-regulated in the transcription regulatory networks and shared similar neighbors in the protein-protein networks were more likely to be co-expressed. Moreover, their biological functions were closely related.

  • 114.
    Zhang, Suping
    et al.
    Zhejiang Univ, Coll Med, Affiliated Hosp 1, Kidney Dis Ctr, Hangzhou, Zhejiang, Peoples R China;Zhejiang Univ, Sch Basic Med Sci, Dept Physiol, Sch Med, Hangzhou, Zhejiang, Peoples R China.
    Huang, Qian
    Quanzhou Med Coll, Dept Physiol, Quanzhou, Peoples R China.
    Cai, Xiaoxia
    Honghe Hlth Vocat Coll, Dept Basic Med Sci, Mengzi, Peoples R China.
    Jiang, Shan
    Zhejiang Univ, Coll Med, Affiliated Hosp 1, Kidney Dis Ctr, Hangzhou, Zhejiang, Peoples R China;Zhejiang Univ, Sch Basic Med Sci, Dept Physiol, Sch Med, Hangzhou, Zhejiang, Peoples R China.
    Xu, Nan
    Zhejiang Univ, Coll Med, Affiliated Hosp 1, Kidney Dis Ctr, Hangzhou, Zhejiang, Peoples R China;Zhejiang Univ, Sch Basic Med Sci, Dept Physiol, Sch Med, Hangzhou, Zhejiang, Peoples R China.
    Zhou, Qin
    Zhejiang Univ, Coll Med, Affiliated Hosp 1, Kidney Dis Ctr, Hangzhou, Zhejiang, Peoples R China;Zhejiang Univ, Sch Basic Med Sci, Dept Physiol, Sch Med, Hangzhou, Zhejiang, Peoples R China.
    Cao, Xiaoyun
    Zhejiang Univ, Coll Med, Affiliated Hosp 1, Kidney Dis Ctr, Hangzhou, Zhejiang, Peoples R China;Zhejiang Univ, Sch Basic Med Sci, Dept Physiol, Sch Med, Hangzhou, Zhejiang, Peoples R China.
    Hultström, Michael
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för kirurgiska vetenskaper, Anestesiologi och intensivvård. Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för medicinsk cellbiologi.
    Tian, Jiong
    Zhejiang Univ, Coll Med, Affiliated Hosp 1, Kidney Dis Ctr, Hangzhou, Zhejiang, Peoples R China;Zhejiang Univ, Sch Basic Med Sci, Dept Physiol, Sch Med, Hangzhou, Zhejiang, Peoples R China.
    Lai, En Yin
    Zhejiang Univ, Coll Med, Affiliated Hosp 1, Kidney Dis Ctr, Hangzhou, Zhejiang, Peoples R China;Zhejiang Univ, Sch Basic Med Sci, Dept Physiol, Sch Med, Hangzhou, Zhejiang, Peoples R China.
    Osthole Ameliorates Renal Fibrosis in Mice by Suppressing Fibroblast Activation and Epithelial-Mesenchymal Transition2018Ingår i: Frontiers in Physiology, ISSN 1664-042X, E-ISSN 1664-042X, Vol. 9, artikel-id 1650Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Renal fibrosis is a common pathway of virtually all progressive kidney diseases. Osthole (OST, 7-Methoxy-8-(3-methylbut-2-enyl)-2-chromenone), a derivative of coumarin mainly found in plants of the Apiaceae family, has shown inhibitory effects on inflammation, oxidative stress, fibrosis and tumor progression. The present study investigated whether OST mediates its effect via suppressing fibroblast activation and epithelial-mesenchymal transition (EMT) in unilateral ureteral obstruction (UUO)-induced renal fibrosis in mice. Herein, we found that OST inhibited fibroblast activation in a dose-dependent manner by inhibiting the transforming growth factor-beta 1 (TGF beta 1)-Smad pathway. OST also blocked fibroblast proliferation by reducing DNA synthesis and downregulating the expressions of proliferation- and cell cycle-related proteins including proliferating cell nuclear antigen (PCNA), CyclinD1 and p21 Waf1/Cip1. Meanwhile, in the murine model of renal interstitial fibrosis induced by UUO, myofibroblast activation with increased expression of alpha-smooth muscle actin (alpha-SMA) and proliferation were attenuated by OST treatment. Additionally, we provided in vivo evidence suggesting that OST repressed EMT with preserved E-cadherin and reduced Vimentin expression in obstructed kidney. UUO injury-induced upregulation of EMT-related transcription factors, Snail family transcriptional repressor-1(Snail 1) and Twist family basic helix-loop-helix (BHLH) transcription factor (Twist) as well as elevated G2/M arrest of tubular epithelial cell, were rescued by OST treatment. Further, OST treatment reversed aberrant expression of TGF beta 1-Smad signaling pathway, increased level of proinflammatory cytokines and NF-kappaB (NF-kappa B) activation in kidneys with obstructive nephropathy. Taken together, these findings suggest that OST hinder renal fibrosis in UUO mouse mainly through inhibition of fibroblast activation and EMT.

  • 115. Zhang, Xiang
    et al.
    Mardinoglu, Adil
    KTH, Centra, Science for Life Laboratory, SciLifeLab. Chalmers University of Technology, Sweden.
    Joosten, Leo A. B.
    Kuivenhoven, Jan A.
    Li, Yang
    Netea, Mihai G.
    Groen, Albert K.
    Identification of Discriminating Metabolic Pathways and Metabolites in Human PBMCs Stimulated by Various Pathogenic Agents2018Ingår i: Frontiers in Physiology, ISSN 1664-042X, E-ISSN 1664-042X, Vol. 9, artikel-id 139Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Immunity and cellular metabolism are tightly interconnected but it is not clear whether different pathogens elicit specific metabolic responses. To address this issue, we studied differential metabolic regulation in peripheral blood mononuclear cells (PBMCs) of healthy volunteers challenged by Candida albicans, Borrelia burgdorferi, lipopolysaccharide, and Mycobacterium tuberculosis in vitro. By integrating gene expression data of stimulated PBMCs of healthy individuals with the KEGG pathways, we identified both common and pathogen-specific regulated pathways depending on the time of incubation. At 4 h of incubation, pathogenic agents inhibited expression of genes involved in both the glycolysis and oxidative phosphorylation pathways. In contrast, at 24 h of incubation, particularly glycolysis was enhanced while genes involved in oxidative phosphorylation remained unaltered in the PBMCs. In general, differential gene expression was less pronounced at 4 h compared to 24 h of incubation. KEGG pathway analysis allowed differentiation between effects induced by Candida and bacterial stimuli. Application of genome-scale metabolic model further generated a Candida-specific set of 103 reporter metabolites (e.g., desmosterol) that might serve as biomarkers discriminating Candida stimulated PBMCs from bacteria-stimuated PBMCs. Our analysis also identified a set of 49 metabolites that allowed discrimination between the effects of Borrelia burgdorferi, lipopolysaccharide and Mycobacterium tuberculosis. We conclude that analysis of pathogen-induced effects on PBMCs by a combination of KEGG pathways and genome-scale metabolic model provides deep insight in the metabolic changes coupled to host defense.

  • 116.
    Zhang, Yanru
    et al.
    University of Shanghai for Science and Technology.
    Jiménez-Herrera, María
    Universitat Rovira I Virgili.
    Axelsson, Christer
    Högskolan i Borås, Akademin för vård, arbetsliv och välfärd.
    Cheng, Yunzhang
    University of Shanghai for Science and Technology.
    Not Bad: Passive Leg Raising in Cardiopulmonary Resuscitation-A New Modeling Study2017Ingår i: Frontiers in Physiology, ISSN 1664-042X, E-ISSN 1664-042X, Vol. 7, s. 665-Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Aim: To evaluate, using a simulated haemodynamic circulation model, whether passive leg raising (PLR) is able to improve the effect during cardiopulmonary resuscitation (CPR); to expose the possible reasons why PLR works or not.

    Materials and Methods: We adapted a circulatory model for CPR with PLR. First we compared cardiac output (CO), coronary perfusion pressure (CPP), blood flow to heart (Qheart), and blood flow to neck and brain (Qhead) of standard chest compression-only CPR with and without PLR; second we simulated the effects of PLR in different situations, by varying the thoracic pump factor (TPF) from 0 to 1; third we simulated the effects when the legs are lifted to the different heights. Finally, we compared our results with those obtained from a published clinical study.

    Results: According to the simulation model, (1) When TPF is in the interval (0,1), CPP, CO, Qheart, and Qhead are improved with PLR, among them with half-thoracic/half-cardiac pump effect (TPF is 0.5), CPP, CO, Qhead, and Qheart increase the most (by 14, 14, 15, and 17%). (2) When TPF is 1 (pure thoracic pump, with an emphysema or extremely thick thorax), PLR has almost no effect on CPP, CO, and Qheart (-1, 2, and 0%), whereas Qhead is increased by 9%; (3) Regardless of whether there is a cardiac or thoracic pump effect, PLR is able to increase Qhead by 9-15%. (4) When the legs are lifted to 30 degrees to the ground, the volume transferred from legs to upper body is 36% of the initial volume in legs; when the legs are lifted to 45 degrees , the volume transferred is 43%; when the legs are lifted to 60 degrees , the volume transferred is 47%; when the legs are lifted to 90 degrees , the volume transferred is 50%.

    Conclusion: Generally PLR is able to achieve improved cerebral perfusion and coronary perfusion. In some extreme situations, it has no effect on cardiac output and coronary perfusion, but still improves cerebral perfusion. PLR could be a beneficial supplement to CPR, and it is not necessary to lift the legs too high above the ground.

  • 117.
    Zinner, Christoph
    et al.
    University of Wurzburg, Germany; Mid Sweden University, Sweden.
    Morales-Alamo, David
    University of Las Palmas Gran Canaria, Spain; University of Las Palmas Gran Canaria, Spain.
    Ortenblad, Niels
    Mid Sweden University, Sweden; University of Southern Denmark, Denmark.
    Larsen, Filip J.
    Swedish School Sport and Health Science, Sweden.
    Schiffer, Tomas
    Linköpings universitet, Institutionen för medicin och hälsa, Avdelningen för radiologiska vetenskaper. Linköpings universitet, Medicinska fakulteten.
    Willis, Sarah J.
    Mid Sweden University, Sweden.
    Gelabert-Rebato, Miriam
    University of Las Palmas Gran Canaria, Spain; University of Las Palmas Gran Canaria, Spain.
    Perez-Valera, Mario
    University of Las Palmas Gran Canaria, Spain; University of Las Palmas Gran Canaria, Spain.
    Boushel, Robert
    University of British Columbia, Canada.
    Calbet, Jose A. L.
    University of Las Palmas Gran Canaria, Spain; University of Las Palmas Gran Canaria, Spain; University of British Columbia, Canada.
    Holmberg, Hans-Christer
    Mid Sweden University, Sweden; University of British Columbia, Canada; UiT Arctic University of Norway, Norway.
    The Physiological Mechanisms of Performance Enhancement with Sprint Interval Training Differ between the Upper and Lower Extremities in Humans2016Ingår i: Frontiers in Physiology, ISSN 1664-042X, E-ISSN 1664-042X, Vol. 7, nr 426Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    To elucidate the mechanisms underlying the differences in adaptation of arm and leg muscles to sprint training, over a period of 11 days 16 untrained men performed six sessions of 4-6 x 30-s all-out sprints (SIT) with the legs and arms, separately, with a 1-h interval of recovery. Limb-specific VO(2)peak, sprint performance (two 30-s Wingate tests with 4-min recovery), muscle efficiency and time-trial performance (TT, 5-min all-out) were assessed and biopsies from the m. vastus lateralis and m. triceps brachii taken before and after training. VO(2)peak and Wmax increased 3-11% after training, with a more pronounced change in the arms (P amp;lt; 0.05). Gross efficiency improved for the arms (+8.8%, P amp;lt; 0.05), but not the legs (-0.6%). Wingate peak and mean power outputs improved similarly for the arms and legs, as did TT performance. After training, VO2 during the two Wingate tests was increased by 52 and 6% for the arms and legs, respectively (P amp;lt; 0.001). In the case of the arms, VO2 was higher during the first than second Wingate test (64 vs. 44%, P amp;lt; 0.05). During the TT, relative exercise intensity, HR, VO2, VCO2, V-E, and V-t were all lower during arm-cranking than leg-pedaling, and oxidation of fat was minimal, remaining so after training. Despite the higher relative intensity, fat oxidation was 70% greater during leg-pedaling (P = 0.017). The aerobic energy contribution in the legs was larger than for the arms during the Wingate tests, although VO2 for the arms was enhanced more by training, reducing the O-2 deficit after SIT. The levels of muscle glycogen, as well as the myosin heavy chain composition were unchanged in both cases, while the activities of 3-hydroxyacyl-CoA-dehydrogenase and citrate synthase were elevated only in the legs and capillarization enhanced in both limbs. Multiple regression analysis demonstrated that the variables that predict TT performance differ for the arms and legs. The primary mechanism of adaptation to SIT by both the arms and legs is enhancement of aerobic energy production. However, with their higher proportion of fast muscle fibers, the arms exhibit greater plasticity.

  • 118.
    Zinner, Christoph
    et al.
    Mittuniversitetet, Fakulteten för humanvetenskap, Avdelningen för hälsovetenskap. Univ Wurzburg, Dept Sport Sci, Wurzburg, Germany.
    Morales-Alamo, David
    Univ Las Palmas Gran Canaria, Las Palmas Gran Canaria, Spain.
    Örtenblad, Niels
    Mittuniversitetet, Fakulteten för humanvetenskap, Avdelningen för hälsovetenskap. Univ Southern Denmark, Inst Sports Sci & Clin Biomech, Odense, Denmark.
    Larsen, Filip J.
    Swedish Sch Sport & Hlth Sci, Stockholm.
    Schiffer, Tomas A.
    Linköping Univ, Dept Med & Hlth Sci, Linköping.
    Willis, Sarah J.
    Mittuniversitetet, Fakulteten för humanvetenskap, Avdelningen för hälsovetenskap.
    Gelabert-Rebato, Miriam
    Univ British Columbia, Sch Kinesiol, Vancouver, BC, Canada.
    Perez-Valera, Mario
    Univ Las Palmas Gran Canaria, Las Palmas Gran Canaria, Spain.
    Boushel, Robert
    Univ British Columbia, Sch Kinesiol, Vancouver, BC, Canada.
    Calbet, Jose A. L.
    Univ British Columbia, Sch Kinesiol, Vancouver, BC, Canada; Univ Las Palmas Gran Canaria, Las Palmas Gran Canaria, Spain.
    Holmberg, Hans-Christer
    Mittuniversitetet, Fakulteten för humanvetenskap, Avdelningen för hälsovetenskap. Univ British Columbia, Sch Kinesiol, Vancouver, BC, Canada; UiT Arctic Univ Norway, Sch Sport Sci, Tromso, Norway.
    The Physiological Mechanisms of Performance Enhancement with Sprint Interval Training Differ between the Upper and Lower Extremities in Humans2016Ingår i: Frontiers in Physiology, ISSN 1664-042X, E-ISSN 1664-042X, Vol. 7, nr SEP, artikel-id 426Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    To elucidate the mechanisms underlying the differences in adaptation of arm and leg muscles to sprint training, over a period of 11 days 16 untrained men performed six sessions of 4-6 x 30-s all-out sprints (SIT) with the legs and arms, separately, with a 1-h interval of recovery. Limb-specific VO(2)peak, sprint performance (two 30-s Wingate tests with 4-min recovery), muscle efficiency and time-trial performance (TT, 5-min all-out) were assessed and biopsies from the m. vastus lateralis and m. triceps brachii taken before and after training. VO(2)peak and Wmax increased 3-11% after training, with a more pronounced change in the arms (P < 0.05). Gross efficiency improved for the arms (+8.8%, P < 0.05), but not the legs (-0.6%). Wingate peak and mean power outputs improved similarly for the arms and legs, as did TT performance. After training, VO2 during the two Wingate tests was increased by 52 and 6% for the arms and legs, respectively (P < 0.001). In the case of the arms, VO2 was higher during the first than second Wingate test (64 vs. 44%, P < 0.05). During the TT, relative exercise intensity, HR, VO2, VCO2, V-E, and V-t were all lower during arm-cranking than leg-pedaling, and oxidation of fat was minimal, remaining so after training. Despite the higher relative intensity, fat oxidation was 70% greater during leg-pedaling (P = 0.017). The aerobic energy contribution in the legs was larger than for the arms during the Wingate tests, although VO2 for the arms was enhanced more by training, reducing the O-2 deficit after SIT. The levels of muscle glycogen, as well as the myosin heavy chain composition were unchanged in both cases, while the activities of 3-hydroxyacyl-CoA-dehydrogenase and citrate synthase were elevated only in the legs and capillarization enhanced in both limbs. Multiple regression analysis demonstrated that the variables that predict TT performance differ for the arms and legs. The primary mechanism of adaptation to SIT by both the arms and legs is enhancement of aerobic energy production. However, with their higher proportion of fast muscle fibers, the arms exhibit greater plasticity.

  • 119. Zinner, Christoph
    et al.
    Morales-Alamo, David
    Ørtenblad, Niels
    Larsen, Filip J
    Gymnastik- och idrottshögskolan, GIH, Institutionen för idrotts- och hälsovetenskap, Åstrandlaboratoriet, Forskningsgruppen Mitokondriell funktion och metabolisk kontroll.
    Schiffer, Tomas A
    Willis, Sarah J
    Gelabert-Rebato, Miriam
    Perez-Valera, Mario
    Boushel, Robert
    Calbet, Jose A L
    Holmberg, Hans-Christer
    The Physiological Mechanisms of Performance Enhancement with Sprint Interval Training Differ between the Upper and Lower Extremities in Humans.2016Ingår i: Frontiers in Physiology, ISSN 1664-042X, E-ISSN 1664-042X, Vol. 7, artikel-id 426Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    To elucidate the mechanisms underlying the differences in adaptation of arm and leg muscles to sprint training, over a period of 11 days 16 untrained men performed six sessions of 4-6 × 30-s all-out sprints (SIT) with the legs and arms, separately, with a 1-h interval of recovery. Limb-specific VO2peak, sprint performance (two 30-s Wingate tests with 4-min recovery), muscle efficiency and time-trial performance (TT, 5-min all-out) were assessed and biopsies from the m. vastus lateralis and m. triceps brachii taken before and after training. VO2peak and Wmax increased 3-11% after training, with a more pronounced change in the arms (P < 0.05). Gross efficiency improved for the arms (+8.8%, P < 0.05), but not the legs (-0.6%). Wingate peak and mean power outputs improved similarly for the arms and legs, as did TT performance. After training, VO2 during the two Wingate tests was increased by 52 and 6% for the arms and legs, respectively (P < 0.001). In the case of the arms, VO2 was higher during the first than second Wingate test (64 vs. 44%, P < 0.05). During the TT, relative exercise intensity, HR, VO2, VCO2, VE, and Vt were all lower during arm-cranking than leg-pedaling, and oxidation of fat was minimal, remaining so after training. Despite the higher relative intensity, fat oxidation was 70% greater during leg-pedaling (P = 0.017). The aerobic energy contribution in the legs was larger than for the arms during the Wingate tests, although VO2 for the arms was enhanced more by training, reducing the O2 deficit after SIT. The levels of muscle glycogen, as well as the myosin heavy chain composition were unchanged in both cases, while the activities of 3-hydroxyacyl-CoA-dehydrogenase and citrate synthase were elevated only in the legs and capillarization enhanced in both limbs. Multiple regression analysis demonstrated that the variables that predict TT performance differ for the arms and legs. The primary mechanism of adaptation to SIT by both the arms and legs is enhancement of aerobic energy production. However, with their higher proportion of fast muscle fibers, the arms exhibit greater plasticity.

  • 120.
    Zoppirolli, Chiara
    et al.
    CeRiSM Res Ctr Sport Mt & Hlth, Rovereto, Italy; Univ Verona, Verona, Italy.
    Bortolan, Lorenzo
    CeRiSM Res Ctr Sport Mt & Hlth, Rovereto, Italy; Univ Verona, Verona, Italy.
    Stella, Federico
    CeRiSM Res Ctr Sport Mt & Hlth, Rovereto, Italy; Univ Verona, Verona, Italy.
    Boccia, Gennaro
    Univ Turin, NeuroMuscularFunct Res Grp, Turin, Italy.
    Holmberg, Hans-Christer
    Mittuniversitetet, Fakulteten för humanvetenskap, Avdelningen för hälsovetenskap. UiT Arctic Univ Norway, Tromso, Norway.
    Schena, Federico
    CeRiSM Res Ctr Sport Mt & Hlth, Rovereto, Italy; Univ Verona, Verona, Italy.
    Pellegrini, Barbara
    CeRiSM Res Ctr Sport Mt & Hlth, Rovereto, Italy; Univ Verona, Verona, Italy.
    Following a Long-Distance Classical Race the Whole-Body Kinematics of Double Poling by Elite Cross-Country Skiers Are Altered2018Ingår i: Frontiers in Physiology, ISSN 1664-042X, E-ISSN 1664-042X, Vol. 9, nr JUL, artikel-id 978Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Introduction: Although short-term (approximately 10-min) fatiguing DP has been reported not to alter the joint kinematics or displacement of the centre of mass (COM) of high-level skiers, we hypothesize that prolonged DP does change these kinematics, since muscular strength is impaired following endurance events lasting longer than 2 h. Methods: During the 58-km Marcialonga race in 2017, the fastest 15 male skiers were videofilmed (100 fps, FHD resolution in the sagittal plane) on two 20-m sections (inclines: 0.7 +/- 0.1 degrees) 48 km apart (i.e., 7 and 55 km from the start), approximating 50-km Olympic races. The cameras were positioned perpendicular to and about 40 m from the middle of each section and spatial dimensions adjusted for each individual track skied. Pole and joint kinematics, as well as displacement of the COM during two DP cycles were assessed. Results: The 10 skiers who fulfilled our inclusion criteria finished the race in 2 h 09 min 19 s +/- 28 s. Displacements of the joints and COM were comparable to previous observations on skiers roller skiing on a flat treadmill at similar speeds in the laboratory. 55 km after the start, cycle velocity and length were lower (P < 0.001 and P = 0.002, respectively) and the angular range of elbow joint flexion during the initial part of the poling phase reduced, while shoulder angle was greater during the first 35% of the DP cycle (all P < 0.05). Moreover, the ankle angle was increased and forward displacement of the COM reduced during the first 80% of the cycle. Conclusion: Prolonged DP reduced the forward displacement of the COM and altered arm kinematics during the early poling phase. The inefficient utilization of COM observed after 2 h of competition together with potential impairment of the stretch-shortening of arm extensor muscles probably attenuated generation of poling force. To minimize these effects of fatigue, elite skiers should focus on maintaining optimal elbow and ankle kinematics and an effective forward lean during the propulsive phase of DP.

  • 121. Šarabon, N.
    et al.
    Mekjavić, I. B.
    Eiken, Ola
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Medicinteknik och hälsosystem, Omgivningsfysiologi. KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Centra, Centrum för flyg- och rymdfysiologi, SAPC.
    Babič, J.
    The effect of bed rest and hypoxic environment on postural balance and trunk automatic (re)actions in young healthy males2018Ingår i: Frontiers in Physiology, ISSN 1664-042X, E-ISSN 1664-042X, Vol. 9, nr January, artikel-id 27Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Prolonged inactivity, such as bed rest induces several detrimental changes within a short timeframe. Impaired postural balance and responses of trunk muscles to (un)expected perturbations were both shown to be impaired after bed rest. Certain populations (e.g., astronauts) are exposed to hypoxic environment in addition to inactivity, similar to bed rest. While the isolated negative effects of hypoxia on postural balance have been observed before, no study to date has examined the combined effects of hypoxia and bed rest on postural balance or trunk muscle responses. In this study, we examined the effects of 21-day exposure to three conditions: (i) bed rest in hypoxic environment (HBR), (ii) bed rest in normoxic environment (NBR), and (iii) ambulatory hypoxic environment (HAMB). Fourteen healthy male subjects crossed over between conditions in a randomized order, with a 4-month break between conditions to ensure full recovery. Most body sway parameters indicated a similar deterioration of postural balance following both HBR and NBR. Similarly, both anticipatory and reactive responses of the trunk muscles (m. erector spinae and m. multifidus) were impaired after HBR and NBR to a similar degree and mostly unchanged after HAMB. Certain body sway parameters were impaired after HAMB, confirming that hypoxia alone can undermine postural balance. On the other hand, some trunk responses were improved after HAMB. In conclusion, the results of our study confirmed previous findings on negative effects of bed rest, but showed little or no additional effect of hypoxia during bed rest. Physical activity during bed rest is encouraged to preserve neuromuscular functions of the trunk. While the HBR condition in our study resembled conditions during space missions, our results could be relevant to other populations, such as patients with pulmonary diseases exposed to bed rest.

  • 122. Šket, R.
    et al.
    Debevec, T.
    Kublik, S.
    Schloter, M.
    Schoeller, A.
    Murovec, B.
    Mikuš, K. V.
    Makuc, D.
    Pečnik, K.
    Plavec, J.
    Mekjavić, I. B.
    Eiken, Ola
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Medicinteknik och hälsosystem, Omgivningsfysiologi. KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Centra, Centrum för flyg- och rymdfysiologi, SAPC.
    Prevoršek, Z.
    Stres, B.
    Intestinal metagenomes and metabolomes in healthy young males: Inactivity and hypoxia generated negative physiological symptoms precede microbial dysbiosis2018Ingår i: Frontiers in Physiology, ISSN 1664-042X, E-ISSN 1664-042X, Vol. 9, nr Mars, artikel-id 198Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We explored the metagenomic, metabolomic and trace metal makeup of intestinal microbiota and environment in healthy male participants during the run-in (5 day) and the following three 21-day interventions: normoxic bedrest (NBR), hypoxic bedrest (HBR) and hypoxic ambulation (HAmb) which were carried out within a controlled laboratory environment (circadian rhythm, fluid and dietary intakes, microbial bioburden, oxygen level, exercise). The fraction of inspired O2 (FiO2) and partial pressure of inspiredO2 (PiO2) were 0.209 and 133.1 ± 0.3 mmHg for the NBR and 0.141 ± 0.004 and 90.0 ± 0.4 mmHg (~4,000 m simulated altitude) for HBR and HAmb interventions, respectively. Shotgun metagenomes were analyzed at various taxonomic and functional levels, 1H-and 13C-metabolomes were processed using standard quantitative and human expert approaches, whereas metals were assessed using X-ray fluorescence spectrometry. Inactivity and hypoxia resulted in a significant increase in the genus Bacteroides in HBR, in genes coding for proteins involved in iron acquisition and metabolism, cell wall, capsule, virulence, defense and mucin degradation, such as beta-galactosidase (EC3.2.1.23), α-L-fucosidase (EC3.2.1.51), Sialidase (EC3.2.1.18), and α-N-acetylglucosaminidase (EC3.2.1.50). In contrast, the microbial metabolomes, intestinal element and metal profiles, the diversity of bacterial, archaeal and fungal microbial communities were not significantly affected. The observed progressive decrease in defecation frequency and concomitant increase in the electrical conductivity (EC) preceded or took place in absence of significant changes at the taxonomic, functional gene, metabolome and intestinal metal profile levels. The fact that the genus Bacteroides and proteins involved in iron acquisition and metabolism, cell wall, capsule, virulence and mucin degradation were enriched at the end of HBR suggest that both constipation and EC decreased intestinal metal availability leading to modified expression of co-regulated genes in Bacteroides genomes. Bayesian network analysis was used to derive the first hierarchical model of initial inactivity mediated deconditioning steps over time. The PlanHab wash-out period corresponded to a profound life-style change (i.e., reintroduction of exercise) that resulted in stepwise amelioration of the negative physiological symptoms, indicating that exercise apparently prevented the crosstalk between the microbial physiology, mucin degradation and proinflammatory immune activities in the host.

  • 123. Šket, Robert
    et al.
    Treichel, Nicole
    Debevec, Tadej
    Eiken, Ola
    KTH, Skolan för teknik och hälsa (STH), Naturvetenskap och biomedicin, Omgivningsfysiologi.
    Mekjavic, Igor
    Schloter, Michael
    Vital, Marius
    Chandler, Jenna
    Tiedje, James M.
    Murovec, Boštjan
    Prevoršek, Zala
    Stres, Blaž
    Hypoxia and Inactivity Related Physiological Changes (Constipation, Inflammation) Are Not Reflected at the Level of Gut Metabolites and Butyrate Producing Microbial Community: The PlanHab Study2017Ingår i: Frontiers in Physiology, ISSN 1664-042X, E-ISSN 1664-042X, Vol. 8, nr 4, artikel-id 250Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We explored the assembly of intestinal microbiota in healthy male participants during the run-in (5 day) and experimental phases [21-day normoxic bed rest (NBR), hypoxic bedrest (HBR)], and hypoxic ambulation (HAmb) in a strictly controlled laboratory environment, balanced fluid, and dietary intakes, controlled circadian rhythm, microbial ambiental burden, and 24/7 medical surveillance. The fraction of inspired O2 (FiO2) and partial pressure of inspired O2 (PiO2) were 0.209 and 133.1 ± 0.3 mmHg for NBR and 0.141 ± 0.004 and 90.0 ± 0.4 mmHg for both hypoxic variants (HBR and HAmb; ~4,000 m simulated altitude), respectively. A number of parameters linked to intestinal transit spanning Bristol Stool Scale, defecation rates, zonulin, α1-antitrypsin, eosinophil derived neurotoxin, bile acids, reducing sugars, short chain fatty acids, total soluble organic carbon, water content, diet composition, and food intake were measured (167 variables). The abundance, structure, and diversity of butyrate producing microbial community were assessed using the two primary bacterial butyrate synthesis pathways, butyryl-CoA: acetate CoA-transferase (but) and butyrate kinase (buk) genes. Inactivity negatively affected fecal consistency and in combination with hypoxia aggravated the state of gut inflammation (p < 0.05). In contrast, gut permeability, various metabolic markers, the structure, diversity, and abundance of butyrate producing microbial community were not significantly affected. Rearrangements in the butyrate producing microbial community structure were explained by experimental setup (13.4%), experimentally structured metabolites (12.8%), and gut metabolite-immunological markers (11.9%), with 61.9% remaining unexplained. Many of the measured parameters were found to be correlated and were hence omitted from further analyses. The observed progressive increase in two immunological intestinal markers suggested that the transition from healthy physiological state toward the developed symptoms of low magnitude obesity-related syndromes was primarily driven by the onset of inactivity (lack of exercise in NBR) that were exacerbated by systemic hypoxia (HBR) and significantly alleviated by exercise, despite hypoxia (HAmb). Butyrate producing community in colon exhibited apparent resilience toward short-term modifications in host exercise or hypoxia. Progressive constipation (decreased intestinal motility) and increased local inflammation marker suggest that changes in microbial colonization and metabolism were taking place at the location of small intestine.

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