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  • 401.
    Tonkonogi, Michail
    Högskolan Dalarna, Akademin Utbildning, hälsa och samhälle, Medicinsk vetenskap.
    Alla äldre behöver denna träning2017Ingår i: Här&Nu, ISSN 1653-2287, nr 4, s. 13-13Artikel i tidskrift (Övrig (populärvetenskap, debatt, mm))
  • 402.
    Tonkonogi, Michail
    Högskolan Dalarna, Akademin Hälsa och samhälle, Medicinsk vetenskap.
    Antioxidanter och träning: sanningar och myter2013Ingår i: Bågskytten, ISSN 0345-1216, Vol. 66, nr 6, s. 23-25Artikel i tidskrift (Övrig (populärvetenskap, debatt, mm))
  • 403.
    Tonkonogi, Michail
    Högskolan Dalarna, Akademin Utbildning, hälsa och samhälle, Medicinsk vetenskap.
    Bästa träningen är den som blir av2017Ingår i: Här&Nu, ISSN 1653-2287, nr 5, s. 17-17Artikel i tidskrift (Övrig (populärvetenskap, debatt, mm))
  • 404.
    Tonkonogi, Michail
    Högskolan Dalarna, Akademin Hälsa och samhälle, Medicinsk vetenskap.
    Bågskytte - en precisionsidrott med höga krav på specifik styrka2014Ingår i: Bågskytten, ISSN 0345-1216, Vol. 67, nr 4, s. 13-15Artikel i tidskrift (Övrig (populärvetenskap, debatt, mm))
  • 405.
    Tonkonogi, Michail
    Högskolan Dalarna, Akademin Utbildning, hälsa och samhälle, Medicinsk vetenskap.
    Det viktigaste du behöver veta om styrketräning för barn2020Ingår i: Svensk Idrottsforskning: Organ för Centrum för Idrottsforskning, ISSN 1103-4629Artikel i tidskrift (Övrigt vetenskapligt)
  • 406.
    Tonkonogi, Michail
    Högskolan Dalarna, Akademin Utbildning, hälsa och samhälle, Medicinsk vetenskap.
    För att få resultat måste man äta rätt2018Ingår i: Här&Nu, ISSN 1653-2287, nr 1, s. 15-15Artikel i tidskrift (Övrig (populärvetenskap, debatt, mm))
  • 407.
    Tonkonogi, Michail
    Högskolan Dalarna, Akademin Utbildning, hälsa och samhälle, Medicinsk vetenskap.
    Idrottsmedicinen sviker barnen2012Ingår i: Svenska Dagbladet, ISSN 1101-2412, nr 25 nov, s. 5-5Artikel i tidskrift (Övrig (populärvetenskap, debatt, mm))
  • 408.
    Tonkonogi, Michail
    Högskolan Dalarna, Akademin Utbildning, hälsa och samhälle, Medicinsk vetenskap.
    Inget ont som inte medför något gott2018Ingår i: här&nu, ISSN 1653-2287, nr 5, s. 9-Artikel i tidskrift (Övrig (populärvetenskap, debatt, mm))
  • 409.
    Tonkonogi, Michail
    Högskolan Dalarna, Akademin Hälsa och samhälle, Medicinsk vetenskap.
    Inverkan av akut arbete, träning och oxidativ stress på mitokondriell funktion och termogenes i human skelettmuskulatur.1999Ingår i: Svensk Idrottsmedicin, ISSN 1103-7652, nr 2, s. 5-10Artikel i tidskrift (Övrigt vetenskapligt)
  • 410.
    Tonkonogi, Michail
    Högskolan Dalarna, Akademin Utbildning, hälsa och samhälle, Medicinsk vetenskap.
    Jag vill leva jag vill dö i Norden...2016Ingår i: här&nu, ISSN 1653-2287, nr 6, s. 15-15Artikel i tidskrift (Övrig (populärvetenskap, debatt, mm))
  • 411.
    Tonkonogi, Michail
    Högskolan Dalarna, Akademin Utbildning, hälsa och samhälle, Medicinsk vetenskap.
    Klassa efter syreupptagning bättre sätt att stoppa doping2018Ingår i: Dagens Nyheter, ISSN 1101-2447, nr 2018-02-10, s. 5-5Artikel i tidskrift (Övrig (populärvetenskap, debatt, mm))
  • 412.
    Tonkonogi, Michail
    Högskolan Dalarna, Akademin Utbildning, hälsa och samhälle, Medicinsk vetenskap.
    Lagstifta om att barn måste röra på sig2019Ingår i: Svenska dagbladet, ISSN 1101-2412, , s. 1artikel-id 2019-11-22Artikel i tidskrift (Övrig (populärvetenskap, debatt, mm))
  • 413.
    Tonkonogi, Michail
    Högskolan Dalarna, Akademin Hälsa och samhälle, Medicinsk vetenskap.
    Mitochondrial function in human skeletal muscle: with special reference to exercise and training.2000Doktorsavhandling, monografi (Övrigt vetenskapligt)
    Abstract [en]

    The overall objective of this thesis was to study the adaptation of oxidative function in human skeletal muscle to acute exercise of different modes, intensities and durations, and to endurance training. The effects of endurance training on mitochondrial function were evaluated in cross-sectional and longitudinal studies by measurements of mitochondrial oxygen consumption in isolated mitochondria and permeabilised muscle fibres and measurements of mitochondrial ATP production rate in isolated mitochondria. A positive correlation was observed between maximal mitochondrial oxidative power measured in isolated mitochondria and permeabilised muscle fibres and other parameters related to local and whole body aerobic training status such as pulmonary maximal oxygen uptake, lactate threshold, and muscle activity of citrate synthase (CS). Previous studies have demonstrated that ADP and creatine are important regulators of oxidative phosphorylation. We found that the sensitivity of oxidative phosphorylation to ADP at the level of individual mitochondrion exhibits negative correlation with training status, whereas the creatine control of mitochondrial respiration is more pronounced in aerobically well-trained individuals. It is suggested that these adaptations may improve the potential for regulation of oxidative metabolism in trained muscle. The sensitivity of proton leakdependent oxygen consumption in isolated mitochondria to free fatty acids was up-regulated by a short-term endurance-training program. This may contribute to a higher basal metabolic rate in endurance-trained individuals. It is also suggested that this adaptation may prevent excessive free radical generation and enhance the potential for regulation of aerobic energy production in trained muscle. Exposure of isolated mitochondria to reactive oxygen species (ROS) reduced maximal ADP-stimulated respiration and P/O ratio and increased noncoupled respiration rate. The sensitivity of non-coupled respiration in isolated mitochondria to ROS was increased by 6 wk of endurance training, whereas the sensitivity of maximal ADP-stimulated respiration and P/O ratio to ROS was unaffected. These results indicate that inner mitochondrial membrane becomes more sensitive to oxidative stress after short-term endurance training. Activities of muscle antioxidative enzymes (SOD, GPX) and glutathione status were unaffected by training. This will result in a lowered antioxidative protection per mitochondrion, which may increase the susceptibility of inner membrane to oxidative stress. Maximal mitochondrial oxidative power in human vastus lateralis muscle was found to be intact or improved after high-intensity intermittent and moderate-intensity prolonged concentric cycling exercise as well as after eccentric cycling. Prolonged exercise increased the non-coupled mitochondrial respiration rate, which may contribute to the excess post-exercise oxygen consumption. After prolonged exercise an acute increase in muscle CS activity was observed. High-intensity intermittent exercise affected the ADP control of oxidative phosphorylation, as evidenced by transient decrease in ADP sensitivity of mitochondrial respiration in permeabilised muscle fibres. ADP sensitivity was unchanged after prolonged concentric and high-intensity eccentric exercise. Taken together these results indicate that mitochondrial function in human muscle is affected differently by exercise of different types. The effect of lactic acidosis on oxidative phosphorylation was evaluated in isolated mitochondria from rat skeletal muscle. It was demonstrated that acidosis induced on non-phosphorylating mitochondria reduces rate of subsequent maximal ADP-stimulated respiration. In contrast, when actively phosphorylating mitochondria were exposed to acidosis maximal ADP-stimulated respiration remained unchanged. On the basis of these results we suggested that the influence of lactic acidosis on muscle aerobic energy production may depend on the physiological conditions at the onset of acidity. Overall, the present investigations indicate that mitochondrial oxidative function is highly responsive to exercise. Endurance training induces adaptation of both quantitative and qualitative aspects of mitochondrial function, which improves the potential for metabolic control. The results suggest that acute physical exercise in humans is, in contrast to previous animal studies, well tolerated by skeletal muscle mitochondria.

  • 414.
    Tonkonogi, Michail
    Högskolan Dalarna, Akademin Hälsa och samhälle, Medicinsk vetenskap.
    Mitokondrier – muskelcellernas kraftverk: anpassnings- och överlevnadskonstnärer som är avgörande för prestation och hälsa.2001Ingår i: Svensk Idrottsforskning: Organ för Centrum för Idrottsforskning, ISSN 1103-4629, nr 1, s. 44-47Artikel i tidskrift (Övrigt vetenskapligt)
  • 415.
    Tonkonogi, Michail
    Högskolan Dalarna, Akademin Utbildning, hälsa och samhälle, Medicinsk vetenskap.
    Musiken kan ge oss bättre resultat2017Ingår i: Här&Nu, ISSN 1653-2287, nr 6, s. 17-Artikel i tidskrift (Övrig (populärvetenskap, debatt, mm))
  • 416.
    Tonkonogi, Michail
    Högskolan Dalarna, Akademin Hälsa och samhälle, Medicinsk vetenskap.
    Muskulaturens förmåga att utnyttja syre är avgörande för prestation och hälsa1998Ingår i: Svensk Idrottsforskning: Organ för Centrum för Idrottsforskning, ISSN 1103-4629, nr 3, s. 34-37Artikel i tidskrift (Övrigt vetenskapligt)
  • 417.
    Tonkonogi, Michail
    Högskolan Dalarna, Akademin Utbildning, hälsa och samhälle, Medicinsk vetenskap.
    Rörelse bästa bot vid artros2017Ingår i: här&nu, ISSN 1653-2287, nr 3, s. 11-Artikel i tidskrift (Övrig (populärvetenskap, debatt, mm))
  • 418.
    Tonkonogi, Michail
    Högskolan Dalarna, Akademin Utbildning, hälsa och samhälle, Medicinsk vetenskap.
    Små förändringar ger stor effekt2018Ingår i: här&nu, ISSN 1653-2287, nr 4, s. 13-Artikel i tidskrift (Övrig (populärvetenskap, debatt, mm))
  • 419.
    Tonkonogi, Michail
    Högskolan Dalarna, Akademin Utbildning, hälsa och samhälle, Medicinsk vetenskap.
    Styrketräna för hjärtat2017Ingår i: här&nu, ISSN 1653-2287, nr 2, s. 23-Artikel i tidskrift (Övrig (populärvetenskap, debatt, mm))
  • 420.
    Tonkonogi, Michail
    Högskolan Dalarna, Akademin Utbildning, hälsa och samhälle, Medicinsk vetenskap.
    Styrketräning bra för balansen2016Ingår i: här&nu, ISSN 1653-2287, nr 5, s. 11-11Artikel i tidskrift (Övrig (populärvetenskap, debatt, mm))
  • 421.
    Tonkonogi, Michail
    Högskolan Dalarna, Akademin Hälsa och samhälle, Medicinsk vetenskap.
    Styrketräning för barn - bu eller bä?2007Ingår i: Svensk Idrottsforskning: Organ för Centrum för Idrottsforskning, ISSN 1103-4629, nr 1, s. 38-43Artikel i tidskrift (Övrigt vetenskapligt)
  • 422.
    Tonkonogi, Michail
    Högskolan Dalarna, Akademin Hälsa och samhälle, Medicinsk vetenskap.
    Styrketräning för barn: Sverige i det internationella perspektivet2013Ingår i: Vaskulär Medicin, ISSN 2000-3188, Vol. 29, nr 1, s. 15-18Artikel i tidskrift (Övrigt vetenskapligt)
  • 423.
    Tonkonogi, Michail
    Högskolan Dalarna, Akademin Hälsa och samhälle, Medicinsk vetenskap.
    Styrketräning för bågskyttar2013Ingår i: Bågskytten, ISSN 0345-1216, Vol. 66, nr 1-2, s. 12-15Artikel i tidskrift (Övrig (populärvetenskap, debatt, mm))
  • 424.
    Tonkonogi, Michail
    Högskolan Dalarna, Akademin Hälsa och samhälle, Medicinsk vetenskap.
    Styrketräning för friska och sjuka barn: Det internationella perspektivet2013Ingår i: Barnbladet, ISSN 0349-1994, Vol. XXXVIII, nr 4, s. 14-16Artikel i tidskrift (Övrigt vetenskapligt)
  • 425.
    Tonkonogi, Michail
    Högskolan Dalarna, Akademin Utbildning, hälsa och samhälle, Medicinsk vetenskap.
    Styrketräning för unga bågskyttar2016Ingår i: Bågskytten, ISSN 0345-1216, Vol. 69, nr 7, s. 12-15Artikel i tidskrift (Övrig (populärvetenskap, debatt, mm))
  • 426.
    Tonkonogi, Michail
    Högskolan Dalarna, Akademin Utbildning, hälsa och samhälle, Medicinsk vetenskap.
    Träna bort depressioner2017Ingår i: här&nu, ISSN 1653-2287, nr 1, s. 11-Artikel i tidskrift (Övrig (populärvetenskap, debatt, mm))
  • 427.
    Tonkonogi, Michail
    Högskolan Dalarna, Akademin Utbildning, hälsa och samhälle, Medicinsk vetenskap.
    Träning bra för nära relationer2016Ingår i: här&nu, ISSN 1653-2287, nr 4, s. 13-13Artikel i tidskrift (Övrig (populärvetenskap, debatt, mm))
  • 428.
    Tonkonogi, Michail
    Högskolan Dalarna, Akademin Utbildning, hälsa och samhälle, Medicinsk vetenskap.
    Träning för hälsa och relationer2017Ingår i: Äldreomsorg, ISSN 1403-7025, nr 3, s. 33-34Artikel i tidskrift (Övrig (populärvetenskap, debatt, mm))
  • 429.
    Tonkonogi, Michail
    Högskolan Dalarna, Akademin Utbildning, hälsa och samhälle, Medicinsk vetenskap.
    Träningslärans grunder - fysiska grundegenskaper och träningsprinciper2018Ingår i: Idrottens träning, Stockholm: SISU Idrottsböcker , 2018, s. 22-57Kapitel i bok, del av antologi (Övrigt vetenskapligt)
  • 430.
    Tonkonogi, Michail
    et al.
    Högskolan Dalarna, Akademin Utbildning, hälsa och samhälle, Medicinsk vetenskap.
    Arkkukangas, Marina
    Strömqvist Bååthe, Karin
    Ekholm, Anna
    The impact of specifically adapted judo-inspired training program on risk factors for falls among adults2020Ingår i: Preventive Medicine Reports, ISSN 0350-1159, E-ISSN 2211-3355Artikel i tidskrift (Refereegranskat)
  • 431.
    Tonkonogi, Michail
    et al.
    Högskolan Dalarna, Akademin Hälsa och samhälle, Medicinsk vetenskap.
    Bellardini, Helena
    Högskolan Dalarna, Akademin Hälsa och samhälle, Idrotts- och hälsovetenskap.
    Fysisk trening for barn och ungdom: for helse, allsidig utvikling og prestasjon2013 (uppl. 1)Bok (Övrig (populärvetenskap, debatt, mm))
  • 432.
    Tonkonogi, Michail
    et al.
    Högskolan Dalarna, Akademin Utbildning, hälsa och samhälle, Medicinsk vetenskap.
    Bellardini, Helena
    Högskolan Dalarna, Akademin Utbildning, hälsa och samhälle, Idrotts- och hälsovetenskap.
    Träna bort den stressrelaterade ohälsan2016 (uppl. 1)Bok (Övrigt vetenskapligt)
  • 433.
    Tonkonogi, Michail
    et al.
    Högskolan Dalarna, Akademin Utbildning, hälsa och samhälle, Medicinsk vetenskap.
    Bellardini, Helena
    Högskolan Dalarna, Akademin Utbildning, hälsa och samhälle, Idrotts- och hälsovetenskap.
    Tunga vikter för en lättare ålderdom2013Ingår i: Svensk Idrottsforskning: Organ för Centrum för Idrottsforskning, ISSN 1103-4629, Vol. 22, nr 3, s. 8-12Artikel i tidskrift (Övrigt vetenskapligt)
  • 434.
    Tonkonogi, Michail
    et al.
    Högskolan Dalarna, Akademin Hälsa och samhälle, Medicinsk vetenskap.
    Fernström, Maria
    Walsh, Brandon
    Ji, Li Li
    Rooyackers, Olav
    Hammaqvist, Folke
    Wernerman, Jan
    Sahlin, Kent
    Reduced oxidative power but unchanged antioxidative capacity in skeletal muscle from aged humans.2003Ingår i: Pflügers Archiv: European Journal of Physiology, ISSN 0031-6768, E-ISSN 1432-2013, Vol. 446, nr 2, s. 261-269Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The hypothesis that the aging process is associated with mitochondrial dysfunction and oxidative stress has been investigated in human skeletal muscle. Muscle biopsy samples were taken from seven old male subjects [OS; 75 (range 61-86) years] and eight young male subjects [YS; 25 (22-31) years]. Oxidative function was measured both in permeabilised muscle fibres and isolated mitochondria. Despite matching the degree of physical activity, OS had a lower training status than YS as judged from pulmonary maximal O2 consumption (V£O2max, m36%) and handgrip strength (m20%). Both maximal respiration and creatine-stimulated respiration were reduced in muscle fibres from OS (m32 and m34%, respectively). In contrast, respiration in isolated mitochondria was similar in OS and YS. The discrepancy might be explained by a biased harvest of "healthy" mitochondria and/or disruption of structural components during the process of isolation. Cytochrome C oxidase was reduced (m40%, P<0.01), whereas UCP3 protein tended to be elevated in OS (P=0.09). Generation of reactive oxygen species by isolated mitochondria and measures of antioxidative defence (muscle content of glutathione, glutathione redox status, antioxidative enzymes activity) were not significantly different between OS and YS. It is concluded that aging is associated with mitochondrial dysfunction, which appears to be unrelated to reduced physical activity. The hypothesis of increased oxidative stress in aged muscle could not be confirmed in this study.

  • 435.
    Tonkonogi, Michail
    et al.
    Högskolan Dalarna, Akademin Hälsa och samhälle, Medicinsk vetenskap.
    Harris, Bearn
    Sahlin, Kent
    Increased activity of citrate synthase in human skeletal muscle after a single bout of prolonged exercise.1997Ingår i: Acta Physiologica Scandinavica, ISSN 0001-6772, E-ISSN 1365-201X, Vol. 161, s. 435-436Artikel i tidskrift (Refereegranskat)
  • 436.
    Tonkonogi, Michail
    et al.
    Högskolan Dalarna, Akademin Hälsa och samhälle, Medicinsk vetenskap.
    Harris, Bearn
    Sahlin, Kent
    Mitochondrial oxidative function in human saponin-skinned muscle fibres: effects of prolonged exercise.1998Ingår i: Journal of Physiology, ISSN 0022-3751, E-ISSN 1469-7793, Vol. 510, s. 279-286Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    1. The influence of prolonged exhaustive exercise on mitochondrial oxidative function was investigated in ten men. 2. Muscle biopsies were taken before and after exercise and mitochondrial respiration investigated in fibre bundles made permeable by pretreatment with saponin. 3. After exercise, respiration in the absence of ADP increased by 18 % (P< 0.01), but respiration at suboptimal ADP concentration (0.1 mM) and maximal ADP-stimulated respiration (1 mM ADP) remained unchanged. 4. In the presence of creatine (20 mM), mitochondrial affinity for ADP increased markedly and respiration at suboptimal ADP concentration (0.1 mM) was similar (pre-exercise) or higher (post-exercise; P< 0.05) than with 1 mM ADP alone. The increase in respiratory rate with creatine was correlated to the relative type I fibre area (r = 0.84). Creatine-stimulated respiration increased after prolonged exercise (P< 0.01). 5. The respiratory control index (6.8 ± 0.4, mean ± s.e.m.) and the ratio between respiration at 0.1 and 1 mM ADP (ADP sensitivity index, 0.63 ± 0.03) were not changed after exercise. The sensitivity index was negatively correlated to the relative type I fibre area (r = -0.86). 6. The influence of exercise on muscle oxidative function has for the first time been investigated with the skinned-fibre technique. It is concluded that maximal mitochondrial oxidative power is intact or improved after prolonged exercise, while uncoupled respiration is increased. The latter finding may contribute to the elevated post-exercise oxygen consumption. The finding that the sensitivity of mitochondrial respiration for ADP and creatine are related to fibre-type composition indicates intrinsic differences in the control of mitochondrial respiration between fibres.

  • 437.
    Tonkonogi, Michail
    et al.
    Högskolan Dalarna, Akademin Utbildning, hälsa och samhälle, Medicinsk vetenskap.
    Hawke, Emma
    Högskolan Dalarna, Akademin Utbildning, hälsa och samhälle, Idrotts- och hälsovetenskap.
    The way that physical education aims to provide the recommended dose of physical activity in school children is multifaceted2017Ingår i: Acta Paediatrica, ISSN 0803-5253, E-ISSN 1651-2227, Vol. 106, nr 1, s. 12-13Artikel i tidskrift (Övrigt vetenskapligt)
  • 438.
    Tonkonogi, Michail
    et al.
    Högskolan Dalarna, Akademin Hälsa och samhälle, Medicinsk vetenskap.
    Henriksson, Jan
    Cotgreave, Ian
    Human skeletal muscle interstitial glutathione levels are elevated in comparison to adipose tissue and blood plasma.2003Ingår i: Archives of Biochemistry and Biophysics, ISSN 0003-9861, E-ISSN 1096-0384, Vol. 413, nr 1, s. 147-149Artikel i tidskrift (Refereegranskat)
  • 439.
    Tonkonogi, Michail
    et al.
    Högskolan Dalarna, Akademin Hälsa och samhälle, Medicinsk vetenskap.
    Krook, Anna
    Walsh, Brandon
    Sahlin, Kent
    Endurance training increases stimulation of uncoupling of skeletal muscle mitochondria in humans by non-esterified fatty acids: an uncoupling-protein-mediated effect?2000Ingår i: Biochemical Journal, ISSN 0264-6021, E-ISSN 1470-8728, Vol. 351, nr 3, s. 805-810Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Uncoupled respiration (UCR) is an essential property of muscle mitochondria and has several functions in the cell. We hypothesized that endurance training may alter the magnitude and properties of UCR in human muscle. Isolated mitochondria from muscle biopsies taken before and after 6 weeks of endurance exercise training (n = 8) were analysed for UCR. To investigate the role of uncoupling protein 2 (UCP2) and UCP3 in UCR, the sensitivity of UCR to UCP-regulating ligands (non-esterified fatty acids and purine nucleotides) and UCP2 and UCP3 mRNA expression in muscle were examined. Oleate increased the mitochondrial oxygen consumption rate, an effect that was not attenuated by GDP and/or cyclosporin A. The effect of oleate was significantly greater after compared with before training. Training had no effect on UCP2 or UCP3 mRNA levels, but after training the relative increase in respiration rate induced by oleate was positively correlated with the UCP2 mRNA level. In conclusion, we show that the sensitivity of UCR to non-esterified fatty acids is up-regulated by endurance training. This suggests that endurance training causes intrinsic changes in mitochondrial function, which may enhance the potential for regulation of aerobic energy production, prevent excess free radical generation and contribute to a higher basal metabolic rate.

  • 440.
    Tonkonogi, Michail
    et al.
    Högskolan Dalarna, Akademin Hälsa och samhälle, Medicinsk vetenskap.
    Sahlin, Kent
    Actively phosphorylating mitochondria are more resistant to lactic acidosis than inactive mitochondria.1999Ingår i: American Journal of Physiology. Cell Physiology, ISSN  0363-6143, Vol. 277, nr 2, s. C288-C293Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Oxidative phosphorylation of isolated rat skeletal muscle mitochondria after exposure to lactic acidosis in either phosphorylating or nonphosphorylating states has been evaluated. Mitochondrial respiration and transmembrane potential (Delta Psi m) were measured with pyruvate and malate as the substrates. The addition of lactic acid decreased the pH of the reaction medium from 7.5 to 6.4. When lactic acid was added to nonphosphorylating mitochondria, the subsequent maximal ADP-stimulated respiration decreased by 27% compared with that under control conditions (P < 0.05), and the apparent Michaelis-Menten constant (Km) for ADP decreased to 10 µM vs. 20 µM (P < 0.05) in controls. In contrast, maximal respiration and ADP sensitivity were not affected when mitochondria were exposed to acidosis during active phosphorylation in state 3. Acidosis significantly increased mitochondrial oxygen consumption in state 4 (post-state 3), irrespective of when acidosis was induced. This effect of acidosis was attenuated in the presence of oligomycin. The addition of lactic acid during state 4 respiration decreased Delta Psi m by 19%. The ratio between added ADP and consumed oxygen (P/O) was close to the theoretical value of 3 in all conditions. The addition of potassium lactate during state 3 (i.e., medium pH unchanged) had no effect on the parameters measured. It is concluded that lactic acidosis has different effects when induced on nonphosphorylating vs. actively phosphorylating mitochondria. On the basis of these results, we suggest that the influence of lactic acidosis on muscle aerobic energy production depends on the physiological conditions at the onset of acidity.

  • 441.
    Tonkonogi, Michail
    et al.
    Högskolan Dalarna, Akademin Hälsa och samhälle, Medicinsk vetenskap.
    Sahlin, Kent
    Physical exercise and mitochondrial function in human skeletal muscle.2002Ingår i: Exercise and Sport Sciences Reviews, ISSN  0091-6331, Vol. 30, nr 3, s. 129-137Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Muscle adaptation to endurance training involves qualitative changes in intrinsic properties of mitochondria. After training, the ADP sensitivity of mitochondrion is decreased whereas the effect of creatine on respiration is increased. This results in an improved control of aerobic energy production. Acute exercise does not adversely affect mitochondrial function.

  • 442.
    Tonkonogi, Michail
    et al.
    Högskolan Dalarna, Akademin Hälsa och samhälle, Medicinsk vetenskap.
    Sahlin, Kent
    Rate of oxidative phosphorylation in isolated mitochondria from human skeletal muscle: effect of training status.1997Ingår i: Acta Physiologica Scandinavica, ISSN 0001-6772, E-ISSN 1365-201X, Vol. 161, s. 345-353Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Muscle oxidative function has been investigated in subjects with various training status (VO2 max, 41–72 mL O2 kg-1 body wt min-1, n=10). Mitochondria were isolated from biopsies taken from m. vastus lateralis. Maximal mitochondrial oxygen consumption (QO2) and ATP production (MAPR) were measured with polarographic and bioluminometric techniques, respectively. The yield of mitochondria, calculated from the fractional activity of citrate synthase (CS), averaged 26%. With pyruvate + malate, the respiratory control ratio was 5.7 ± 0.4 (X ± SE) and the P/O ratio was 2.83 ± 0.02, which demonstrates that the isolated mitochondria were functionally intact. QO2 was significantly correlated to aerobic training status expressed as muscle CS activity (r=0.86), VO2 max (r=0.84) and lactate threshold (r=0.83) but not to the fibre type composition. A highly significant correlation (r=0.93) was observed between ATP production calculated from QO2 and MAPR, but ATP production derived from QO2 was higher than MAPR both for pyruvate + malate (255%) and for a-ketoglutarate (23%). QO2 extrapolated to a temperature of 38 °C averaged 68 mL O2 min-1 kg-1 wet wt, which is similar to previous findings in vitro and in vivo during the post-exercise period. However, calculated muscle O2 utilization during exercise was three- to fivefold higher than QO2 measured on isolated mitochondria. It is suggested that additional factors exist for activation of mitochondrial respiration during exercise. It is concluded that muscle oxidative function can be quantitatively assessed from the respiration of mitochondria isolated from needle biopsy specimens and that QO2 is closely correlated to whole-body VO2 max.

  • 443.
    Tonkonogi, Michail
    et al.
    Högskolan Dalarna, Akademin Hälsa och samhälle, Medicinsk vetenskap.
    Sahlin, Kent
    Fernström, Maria
    The leaky mitochondrion2004Ingår i: Physiology News, ISSN 1476-7996, Vol. 56, s. 27-28Artikel i tidskrift (Refereegranskat)
  • 444.
    Tonkonogi, Michail
    et al.
    Högskolan Dalarna, Akademin Utbildning, hälsa och samhälle, Medicinsk vetenskap.
    Tonkonogi, Aleksandra
    Grundläggande muskel- och neurofysiologi2019Ingår i: Motorisk kontroll och inlärning: Med inriktning på muskoloskeletal rehabilitering / [ed] Ulrik Röijezon, Studentlitteratur AB, 2019, 1, s. 25-36Kapitel i bok, del av antologi (Övrigt vetenskapligt)
  • 445.
    Tonkonogi, Michail
    et al.
    Högskolan Dalarna, Akademin Hälsa och samhälle, Medicinsk vetenskap.
    Walsh, Brandon
    Svensson, Michael
    Sahlin, Kent
    Mitochondrial function and antioxidative defence in human muscle: Effects of endurance training and oxidative stress.2000Ingår i: Journal of Physiology, ISSN 0022-3751, E-ISSN 1469-7793, Vol. 528, nr 2, s. 379-388Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    1. The influence of endurance training on oxidative phosphorylation and the susceptibility of mitochondrial oxidative function to reactive oxygen species (ROS) was investigated in skeletal muscle of four men and four women. Mitochondria were isolated from muscle biopsies taken before and after 6 weeks of endurance training. Mitochondrial respiration was measured before and after exposure of mitochondria to exogenous ROS (H2O2+ FeCl2). 2. Endurance training increased peak pulmonary O2 uptake (VO2,peak) by 24 % and maximal ADP-stimulated mitochondrial oxygen consumption (state 3) by 40 % (P< 0.05). Respiration in the absence of ADP (state 4), the respiratory control ratio (RCR = state 3/state 4) and the ratio between added ADP and consumed oxygen (P/O) remained unchanged by the training programme. 3. Exposure to ROS reduced state 3 respiration but the effect was not significantly different between pre- and post-training samples. State 4 oxygen consumption increased after exposure to ROS both before (+189 %, P< 0.05) and after training (+243 %, P< 0.05) and the effect was significantly higher after training (P< 0.05, pre- vs. post-training). The augmented state 4 respiration could in part be attenuated by atractyloside, which indicates that ADP/ATP translocase was affected by ROS. The P/O ratio in ROS-treated mitochondria was significantly lower (P< 0.05) compared to control conditions, both before (-18.6 ± 2.2 %) and after training (-18.5 ± 1.1 %). 4. Muscle activities of superoxide dismutase (mitochondrial and cytosolic), glutathione peroxidase and muscle glutathione status were unaffected by training. There was a positive correlation between muscle superoxide dismutase activity and age (r= 0.75; P< 0.05; range of age 20–37 years), which may reflect an adaptation to increased generation of ROS in senescent muscle. The muscle glutathione pool was more reduced in subjects with high activity of glutathione peroxidase (r= 0.81; P< 0.05). 5. The influence of short-term training on mitochondrial oxygen consumption has for the first time been investigated in human skeletal muscle. The results showed that maximal mitochondrial oxidative power is increased after endurance training but that the efficiency of energy transfer (P/O ratio) remained unchanged. Antioxidative defence was unchanged after training when expressed relative to muscle weight. Although this corresponds to a reduced antioxidant protection per individual mitochondrion, the sensitivity of aerobic energy transfer to ROS was unchanged. However, the augmented ROS-induced non-coupled respiration after training indicates an increased susceptibility of mitochondrial membrane proton conductance to oxidative stress.

  • 446.
    Tonkonogi, Michail
    et al.
    Högskolan Dalarna, Akademin Hälsa och samhälle, Medicinsk vetenskap.
    Walsh, Brandon
    Söderlund, Karin
    Hultman, Erik
    Saks, Valdur
    Sahlin, Kent
    The role of phosphorylcreatine in the regulation of mitochondrial respiration in human skeletal muscle.2001Ingår i: Journal of Physiology, ISSN 0022-3751, E-ISSN 1469-7793, Vol. 537, nr 3, s. 971-978Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    1. The role of phosphorylcreatine (PCr) and creatine (Cr) in the regulation of mitochondrial respiration was investigated in permeabilised fibre bundles prepared from human vastus lateralis muscle. 2. Fibre respiration was measured in the absence of ADP (V0) and after sequential additions of submaximal ADP (0.1 mm ADP, Vsubmax), PCr (or Cr) and saturating [ADP] (Vmax). 3. Vsubmax increased by 55% after addition of saturating creatine (P< 0.01; n = 8) and half the maximal effect was obtained at 5 mm [Cr]. In contrast, Vsubmax decreased by 54% after addition of saturating phosphorylcreatine (P< 0.01; n = 8) and half the maximal effect was obtained at 1 mm [PCr]. Vmax was not affected by Cr or PCr. 4. Vsubmax was similar when PCr and Cr were added simultaneously at concentrations similar to those in muscle at rest (PCr/Cr = 2) and at low-intensity exercise (PCr/Cr = 0.5). At conditions mimicking high-intensity exercise (PCr/Cr = 0.1), Vsubmax increased to 60% of Vmax (P< 0.01) vs. rest and low-intensity exercise). 5. Eight of the subjects participated in a 16 day Cr supplementation programme. Following Cr supplementation, V0 decreased by 17% (P< 0.01) vs. prior to Cr supplementation), whereas ADP-stimulated respiration (with and without Cr or PCr) was unchanged. 6. For the first time evidence is given that PCr is an important regulator of mitochondrial ADP-stimulated respiration. Phosphorylcreatine decreases the sensitivity of mitochondrial respiration to ADP whereas Cr has the opposite effect. During transition from rest to high-intensity exercise, decreases in the PCr/Cr ratio will effectively increase the sensitivity of mitochondrial respiration to ADP. The decrease in V0 after Cr supplementation indicates that intrinsic changes in membrane proton conductance occur.

  • 447.
    Tonkonogi, Michail
    et al.
    Högskolan Dalarna, Akademin Hälsa och samhälle, Medicinsk vetenskap.
    Walsh, Brandon
    Tiivel, Toomas
    Saks, Valdur
    Sahlin, Kent
    Mitochondrial function in human skeletal muscle is not impaired by high intensity exercise.1999Ingår i: Pflügers Archiv: European Journal of Physiology, ISSN 0031-6768, E-ISSN 1432-2013, Vol. 437, nr 4, s. 562-568Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The hypothesis that high-intensity (HI) intermittent exercise impairs mitochondrial function was investigated with different microtechniques in human muscle samples. Ten male students performed three bouts of cycling at 130% of peak O2 consumption (V·O2,peak). Muscle biopsies were taken from the vastus lateralis muscle at rest, at fatigue and after 110 min recovery. Mitochondrial function was measured both in isolated mitochondria and in muscle fibre bundles made permeable with saponin (skinned fibres). In isolated mitochondria there was no change in maximal respiration, rate of adenosine 5'-triphosphate (ATP) production (measured with bioluminescence) and respiratory control index after exercise or after recovery. The ATP production per consumed oxygen (P/O ratio) also remained unchanged at fatigue but decreased by 4% (P<0.05) after recovery. In skinned fibres, maximal adenosine 5'-diphosphate (ADP)-stimulated respiration increased by 23% from rest to exhaustion (P<0.05) and remained elevated after recovery, whereas the respiratory rates in the absence of ADP and at 0.1 mM ADP (submaximal respiration) were unchanged. The ratio between respiration at 0.1 and 1 mM ADP (ADP sensitivity index) decreased at fatigue (P<0.05) but after the recovery period was not significantly different from that at rest. It is concluded that mitochondrial oxidative potential is maintained or improved during exhaustive HI exercise. The finding that the sensitivity of mitochondrial respiration to ADP is reversibly decreased after strenuous exercise may indicate that the control of mitochondrial respiration is altered.

  • 448. Torell, Matilda F
    et al.
    Strömsöe, Anneli
    Högskolan Dalarna, Akademin Utbildning, hälsa och samhälle, Medicinsk vetenskap.
    Zagerholm, Ellen
    Herlitz, Johan
    Claesson, Andreas
    Svensson, Leif
    Börjesson, Mats
    Higher survival rates in exercise-related out-of-hospital cardiac arrests, compared to non-exercise-related - a study from the Swedish Register of Cardiopulmonary Resuscitation2017Ingår i: European Journal of Preventive Cardiology, ISSN 2047-4873, E-ISSN 2047-4881, Vol. 24, nr 15, s. 1673-1679Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Background: Despite the positive effects of physical activity, the risk of sudden cardiac arrest is transiently increased during and immediately after exercise. The purpose of this study was to assess the incidence of exercise-related out-of-hospital cardiac arrest in the general population and to compare characteristics and prognosis of these cardiac arrests with non-exercise-related out-of-hospital cardiac arrests.

    Methods: Data from all cases of treated out-of-hospital cardiac arrest outside of home reported to the Swedish Register of Cardiopulmonary Resuscitation from 2011-2015 in three counties of Sweden were investigated (population 2.1 m). This registry captures almost 100% of all out-of-hospital cardiac arrests in Sweden. Results Of 1825 out-of hospital cardiac arrests, 137 (7.5%) were exercise-related, resulting in an incidence of 1.2 per 100,000 person-years. The 30-day survival rate was significantly higher among exercise-related out-of hospital cardiac arrests compared to non-exercise-related out-of-hospital cardiac arrests (54.3 % vs 19.4%, p < 0.0001). Patients suffering an exercise-related out-of-hospital cardiac arrest were on average 10 years younger than those who had a non-exercise-related out-of-hospital cardiac arrest, 56.4 years compared to 67.2 years. Exercise-related out-of-hospital cardiac arrests were more often witnessed (89.4% vs 78.6%, p = 0.002), had higher rates of bystander cardiopulmonary resuscitation (80.3% vs 61.0%, p < 0.0001) and were more frequently connected to an automated external defibrillator (20.4% vs 4.6%, p < 0.0001).

    Conclusions: Cardiac arrests that occur in relation to exercise have a significantly better prognosis and outcome than non-exercise-related cardiac arrests. This may be explained by favourable circumstances but may also reflect that these persons experience a sudden cardiac arrest at a lower degree of coronary artery disease, due to their younger age and to exercise being a trigger.

  • 449. Torstensen, Tom Arild
    et al.
    Grooten, Wilhelmus J A
    Østerås, Håvard
    Heijne, Annette
    Harms-Ringdahl, Karin
    Äng, Björn
    Högskolan Dalarna, Akademin Utbildning, hälsa och samhälle, Medicinsk vetenskap.
    How does exercise dose affect patients with long-term osteoarthritis of the knee? A study protocol of a randomised controlled trial in Sweden and Norway: the SWENOR Study2018Ingår i: BMJ Open, ISSN 2044-6055, E-ISSN 2044-6055, Vol. 8, nr 5, artikel-id e018471Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    INTRODUCTION: Osteoarthritis (OA) of the knee is characterised by knee pain, disability and degenerative changes, and places a burden on societies all over the world. Exercise therapy is an often-used modality, but there is little evidence of what type of exercise dose is the most effective, indicating a need for controlled studies of the effect of different dosages. Thus, the aim of the study described in this protocol is to evaluate the effects of high-dose versus low-dose medical exercise therapy (MET) in patients with knee OA.

    METHODS AND ANALYSIS: This is a multicentre prospective randomised two-arm trial with blinded assessment and data analysis. We are planning to include 200 patients aged 45-85 years with symptomatic (pain and decreased functioning) and X-ray verified diagnosis of knee OA. Those eligible for participation will be randomly allocated to either high-dose (n=100) or low-dose (n=100) MET. All patients receive three supervised treatments each week for 12 weeks, giving a total of 36 MET sessions. The high-dose group exercises for 70-90 min compared with 20-30 min for the low-dose group. The high-dose group exercises for a longer time, and receives a greater number of exercises with more repetitions and sets. Background and outcome variables are recorded at inclusion, and outcome measures are collected after every sixth treatment, at the end of treatment, and at 6-month and 12-month follow-ups. Primary outcome is self-rated knee functioning and pain using the Knee Injury and Osteoarthritis Outcome Score (KOOS). The primary end point is at the end of treatment after 3 months, and secondary end points are at 6 months and 12 months after the end of treatment.

    ETHICS AND DISSEMINATION: This project has been approved by the Regional Research Ethics Committees in Stockholm, Sweden, and in Norway. Our results will be submitted to peer-reviewed journals and presented at national and international conferences.

    TRIAL REGISTRATION NUMBER: NCT02024126; Pre-results.

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  • 450.
    Tseli, Elena
    et al.
    Karolinska Institutet.
    Grooten, Wilhelmus Johannes Andreas
    Stålnacke, Britt-Marie
    Boersma, Katja
    Enthoven, Paul
    Gerdle, Björn
    Äng, Björn
    Högskolan Dalarna, Akademin Utbildning, hälsa och samhälle, Medicinsk vetenskap. Karolinska institutet.
    Predictors of multidisciplinary rehabilitation outcomes in patients with chronic musculoskeletal pain: protocol for a systematic review and meta-analysis2017Ingår i: Systematic Reviews, E-ISSN 2046-4053, ISSN 2046-4053, Vol. 6, nr 1, artikel-id 199Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    BACKGROUND: Chronic musculoskeletal pain is a major public health problem. Early prediction for optimal treatment results has received growing attention, but there is presently a lack of evidence regarding what information such proactive management should be based on. This study protocol, therefore, presents our planned systematic review and meta-analysis on important predictive factors for health and work-related outcomes following multidisciplinary rehabilitation (MDR) in patients with chronic musculoskeletal pain.

    METHODS: We aim to perform a synthesis of the available evidence together with a meta-analysis of published peer-reviewed original research that includes predictive factors preceding MDR. Included are prospective studies of adults with benign, chronic (> 3 months) musculoskeletal pain diagnoses who have taken part in MDR. In the studies, associations between personal and rehabilitation-based factors and the outcomes of interest are reported. Outcome domains are pain, physical functioning including health-related quality of life, and work ability with follow-ups of 6 months or more. We will use a broad, explorative approach to any presented predictive factors (demographic, symptoms-related, physical, psychosocial, work-related, and MDR-related) and these will be analyzed through (a) narrative synthesis for each outcome domain and (b) if sufficient studies are available, a quantitative synthesis in which variance-weighted pooled proportions will be computed using a random effects model for each outcome domain. The strength of the evidence will be evaluated using the Grading of Recommendations, Assessment, Development and Evaluation.

    DISCUSSION: The strength of this systematic review is that it aims for a meta-analysis of prospective cohort or randomized controlled studies by performing an extensive search of multiple databases, using an explorative study approach to predictive factors, rather than building on single predictor impact on the outcome or on predefined hypotheses. In this way, an overview of factors central to MDR outcome can be made and will help strengthen the evidence base and inform a wide readership including health care practitioners and policymakers.

    SYSTEMATIC REVIEW REGISTRATION: PROSPERO CRD42016025339.

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