1. Non–skin related symptoms are common in chronic spontaneous urticaria and linked to active and uncontrolled disease : results from the chronic urticaria registryPolina Pyatilova, Yana Hackler, Felix Aulenbacher, Riccardo Asero, Andrea Bauer, Mojca Bizjak, Cascia Day, Aurélie Du-Thanh, Joachim Dissemond, Daria Fomina, 2024, izvirni znanstveni članek Ključne besede: chronic spontaneous urticaria, non-skin-related symptoms, malaise, feverjoint, bone, muscle pain
Objavljeno v DiRROS: 09.07.2025; Ogledov: 52; Prenosov: 20
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2. Alterations in Muscle Contractile Properties, Structure, and Function During 10-Day Bed Rest, Post-Recovery, and Following COVID-19 LockdownBoštjan Šimunič, Martino V. Franchi, Fabio Sarto, Elena Monti, zaključena znanstvena zbirka raziskovalnih podatkov Povzetek: We aimed to identify early tensiomyography alterations in six muscles during a 10-day bed rest (BR10), followed by a 30-day recovery period (R+30), and to compare these changes with those observed after the 54-day COVID-19 lockdown in ten healthy males (22.9 ± 5.0 years). Tensiomyography and muscle thickness (sonography) were assessed at baseline, during bed rest, at BR10, R+30, and after the COVID-19 lockdown. Additional assessments included vertical jump performance (force plate), body composition (bioimpedance), physical activity (GPAQ), and lower back pain (VAS). By BR10, participants experienced a 1.9% body mass loss, a 3.8% increase in fat mass, and a 2.4% reduction in muscle mass. While anthropometric parameters returned to baseline by R+30, fat mass increased again by 3.9% post-lockdown. Jump height declined by 10.1% at BR10, returned to baseline at R+30, and remained stable thereafter. Muscle thickness decreased by 7.0% in the vastus lateralis at BR10 and by 10.1% post-lockdown. Tensiomyographic amplitude increased in all five leg muscles prior to BR10, recovered at R+30 and increased again after the COVID-19 lockdown, while a reduction was observed in the erector spinae within the first 48 hours, coinciding with reported lower back pain. In the erector spinae, both delay and contraction time decreased during BR10 and post-lockdown. In contrast, contraction time of the biceps femoris increased before BR10 and remained elevated post-lockdown. Overall, tensiomyographic parameters after the COVID-19 lockdown changed in the same direction as during bed rest, though to a lesser degree, make it a sensitive tool for detecting changes in muscle structural and functional quality after bed rest and reduced activity paradigms.
Ključne besede: Atrophy, Bed rest, Physical inactivity, Skeletal muscle, Tensiomyography
Objavljeno v DiRROS: 25.06.2025; Ogledov: 126; Prenosov: 0
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3. Mitochondrial sensitivity to submaximal [ADP] following bed rest : a novel two-phase approach associated with fibre typesLucrezia Zuccarelli, Maria De Martino, Antonio Filippi, Alice E. Knapton, Benjamin D. Thackray, Giovanni Baldassarre, Boštjan Šimunič, Rado Pišot, Giuseppe Sirago, Elena Monti, Marco Vincenzo Narici, Miriam Isola, Andrew J. Murray, Giovanna Lippe, Bruno Grassi, 2025, izvirni znanstveni članek Povzetek: Background: We recently demonstrated that following a 10-day exposure to inactivity/simulated microgravity impairments ofoxidative metabolism were located ‘upstream’ of mitochondrial function, as evaluated by maximal ADP-stimulated mitochon-drial respiration (JO 2max) determined ex vivo. The aim of this study was to evaluate mitochondrial sensitivity to submaximal[ADP] by an alternative approach aimed at identifying responses associated with fibre type composition.Methods: Isolated permeabilized vastus lateralis fibres were analysed by high-resolution respirometry in 9 young males beforeand after a 10-day horizontal bed rest. Eleven submaximal titrations of ADP (from 12.5 to 10 000 μM) were utilized to assess com-plex I + II-linked ADP sensitivity. We applied to JO 2 versus [ADP] data a traditional Michaelis–Menten kinetics equation, withthe calculation of the apparent K m and maximal respiration (Vmax), and two ‘sequential’ hyperbolic equations, yielding two K mand Vmax values. The two-hyperbolic equations were solved and the [ADP] value corresponding to 50% of JO 2max was calculated.Isoform expression of myosin heavy chains (MyHC) 1, 2A and 2X was also determined. Control experiments were also carriedout on rat skeletal muscle samples with different percentages of MyHC isoforms.Results: The two hyperbolic equations provided an alternative fitting of data and identified two distinct phases of the JO 2 versus[ADP] response: a first phase characterized by low Vmax (Vmax1 , 28 ± 10 pmol s−1 mg−1) and apparent K m (K m1 , 62 ± 54 μM) anda second phase characterized by higher Vmax (Vmax2 , 61 ± 16 pmol s−1 mg−1) and K m (K m2 , 1784 ± 833 μM). Data were confirmedin control experiments carried out in rat muscle samples with different percentages of MyHC isoforms. Correlation and receiveroperating characteristics analyses suggest that the two phases of the response were related to the % of MyHC isoforms.Conclusions: A novel mathematical approach (two sequential hyperbolic functions) for the fitting of JO 2 versus [ADP] data ob-tained by high-resolution respirometry on permeabilized skeletal muscle fibres, obtained in humans and rats, provided an alter-native fitting of the experimental data compared to the traditional Michaelis–Menten kinetics equation. This alternative modelallowed the identification of two distinct phases in the responses, which were related to fibre type composition. A first phase, characterized by low apparent K m and Vmax values, was correlated with the percentage of less oxidative (Type 2A + 2X) MyHCisoforms. A second phase, characterized by high apparent K m and Vmax , was related to more oxidative (Type 1) MyHC isoforms.
Ključne besede: ADP, bed rest, mitochondrial sensitivity, myosin heavy chains, skeletal muscle mitochondria
Objavljeno v DiRROS: 05.05.2025; Ogledov: 264; Prenosov: 102
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4. Neuromotor changes in postural control following bed restRamona Ritzmann, Christoph Centner, Luke Hughes, Janice Waldvogel, Uroš Marušič, 2025, pregledni znanstveni članek Povzetek: Chronic bed rest (BR) serves as a model for studying the effects of prolongedimmobility on physiological and neuromotor functions, particularly postural control. ProlongedBR leads to significant deconditioning of postural balance control, characterized by increasedsway path lengths, sway velocity and fall risk, independent of muscle strength. These changes arelinked to neural adaptations at spinal and supraspinal levels, including structural and functionalbrain changes, such as alterations in grey and white matter, increased cerebellar activation,reduced spinal excitability and increased latencies within reflex circuitries. Additionally, BRdisrupts sensory integration from proprioceptive, visual and vestibular systems, impairing post-ural stability. Visual reliance remains stable during BR, though decreased visual acuity andcontrast sensitivity are noted. Moreover, BR-induced shifts in cerebrospinal fluid contribute toaltered brain activity, impacting sensorimotor function. Vestibular system adaptations, includingchanges in vestibulospinal reflexes, further exacerbate balance impairments. Understanding thesemechanisms is crucial for developing interventions to mitigate the adverse effects of BR onpostural control and prevent prolonged recovery times or increased risk of injury. This reviewhighlights the need for further research into the neural underpinnings of BR-induced posturalinstability, with a focus on sensory integration and neuroplasticity
Ključne besede: atrophy, balance, disuse, immobilization, muscle
Objavljeno v DiRROS: 18.04.2025; Ogledov: 260; Prenosov: 159
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5. Muscle gene electrotransfer is increased by the antioxidant tempol in miceBoštjan Markelc, Gregor Tevž, Maja Čemažar, Simona Kranjc Brezar, Jaka Lavrenčak, Bojana Žegura, Justin Teissié, Gregor Serša, 2012, izvirni znanstveni članek Povzetek: Electropermeabilization (EP) is an effective method of gene transfer into different tissues. During EP, reactive oxygen species (ROS) are formed, which could affect transfection efficiency. The role of generated ROS and the role of antioxidants in electrotransfer in myoblasts in vitro and in Musculus tibialis cranialis in mice were, therefore, investigated. We demonstrate in the study that during EP of C2C12 myoblasts, ROS are generated on the surface of the cells, which do not induce long-term genomic DNA damage. Plasmid DNA for transfection (pEGFP-N1), which is present outside the cells during EP, neutralizes the generated ROS. The ROS generation is proportional to the amplitude of the electric pulses and can be scavenged by antioxidants, such as vitamin C or tempol. When antioxidants were used during gene electrotransfer, the transfection efficiency of C2C12 myoblasts was statistically significantly increased 1.6-fold with tempol. Also in vivo, the transfection efficiency of M. tibialis cranialis in mice was statistically significantly increased 1.4-fold by tempol. The study indicates that ROS are generated on cells during EP and can be scavenged by antioxidants. Specifically, tempol can be used to improve gene electrotransfer into the muscle and possibly also to other tissues.
Ključne besede: electropermeabilization, gene electrotransfer, muscle, tempol, reactive oxygen species
Objavljeno v DiRROS: 26.02.2025; Ogledov: 334; Prenosov: 171
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6. Acute myotonometric changes in the masseter and upper trapezius muscles after upper body quarter stretching and coordination exercises or chewingMarša Magdič, Miloš Kalc, Matjaž Vogrin, 2025, izvirni znanstveni članek Povzetek: Pathologies in neck and masticatory muscles affect muscle tone and biomechanical and viscoelastic properties, necessitating precise assessment for treatment. This study evaluated the impact of two guided interventions—relaxing exercises targeting the neck and masticatory muscles (“Exercise”) and heavy chewing using six chewing gums (“Chewing”)—on the masseter and upper trapezius muscles. Twelve participants (aged 19–40 years) underwent myotonometric assessment pre- and post-intervention, measuring tone, stiffness, decrement, relaxation time, and creep. The results showed significant changes in the masseter muscle after exercise, with increased stiffness (14.46%, p < 0.001) and tone (7.03%, p < 0.001) but decreased creep (−9.71%, p < 0.001) and relaxation time (−11.36%, p < 0.001). Conversely, chewing decreased stiffness (−8.82%, p < 0.001) and tone (−5.53%, p < 0.001), while it increased creep (9.68%, p < 0.001) and relaxation time (9.98%, p < 0.001). In the trapezius muscles, tone decreased after both interventions (Exercise: −7.65%, p < 0.001; Chewing: −1.06%, p = 0.003), while relaxation increased (Exercise: 1.78%, p < 0.001; Chewing: 2.82%, p < 0.001). These findings reveal the distinct effects of exercise and chewing on muscle properties, emphasising the complexity of their therapeutic potential and the need for further investigation.
Ključne besede: muscle tonus, relaxation, masseter muscle, trapezius muscle, intervention studies
Objavljeno v DiRROS: 07.01.2025; Ogledov: 408; Prenosov: 218
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7. Effect of castration method on porcine skeletal muscle fiber traits and transcriptome profilesKlavdija Poklukar Žnidaršič, Anja Erbežnik, Gregor Fazarinc, Kevin Kress, Nina Batorek Lukač, Martin Škrlep, Volker Stefanski, Marjeta Čandek-Potokar, Milka Vrecl, 2024, izvirni znanstveni članek Povzetek: This study examined the effects of immunocastration and surgical castration on the histomorphometric and transcriptome traits of the porcine skeletal muscle. We hypothesized that the differences in duration of androgen deprivation resulting from different castration methods influence skeletal muscle biology in a muscle-specific manner. This was tested by analyzing samples of m. longissimus dorsi (LD) and m. semispinalis capitis (SSC) from immunocastrated (IC; n = 12), entire male (EM; n = 12), and surgically castrated (SC; n = 12) pigs using enzyme/immunohistochemical classification and histomorphometric analysis of myofibers, quantitative PCR, and RNA sequencing. The results confirmed the distinctive histomorphometric profiles of LD and SSC and the castration method related muscle-specific effects at the histomorphometric and transcriptome levels. Long-term androgen deficiency (surgical castration) significantly reduced the proportion of fast-twitch type IIa myofibers in LD (P < 0.05), whereas short-term androgen deprivation (immunocastration) reduced the cross-sectional area of oxidative type I myofibers in SSC (P < 0.05). At the transcriptional level, glycolytic LD adapted to long- and short-term androgen deprivation by upregulating genes controlling myoblast proliferation and differentiation to maintain fiber size. In contrast, increased protein degradation through the ubiquitin ligase-mediated atrophy pathway (significantly increased TRIM63 and FBXO32 expression; P < 0.05) could underly reduced crosssectional area of type I myofibers in the oxidative SSC in IC. Potential candidate genes (HK2, ARID5B, SERPINE1, and SCD) linked to specific metabolic profiles and meat quality traits were also identified in IC, providing a foundation for studying the effects of immunocastration on skeletal muscle fiber and carcass/meat quality traits.
Ključne besede: sceletal muscle, Logissimus dorsi, Semispinalis capitis, castration method, genne expression, pig
Objavljeno v DiRROS: 31.12.2024; Ogledov: 420; Prenosov: 198
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8. Influence of smoking method and anatomical location on the content of polycylcic aromatic hydrocarbons in Turopooje hamDanijel Karolyi, Sandra Petričević, Zoran Luković, Dubravko Škorput, Ana Kaić, Krešimir Salajpal, Marjeta Čandek-Potokar, 2024, izvirni znanstveni članek Ključne besede: dry-cured ham, meat smoking, PAH compounds, muscle, Turopolje pig
Objavljeno v DiRROS: 23.12.2024; Ogledov: 404; Prenosov: 279
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9. Initial glutathione depletion during short-term bed rest : pinpointing synthesis and degradation checkpoints in the γ-glutamyl cycleFilippo Giorgio Di Girolamo, Filippo Mearelli, Mariella Sturma, Nicola Fiotti, Kaja Teraž, Alja Ivetac, Alessio Nunnari, Pierandrea Vinci, Boštjan Šimunič, Rado Pišot, Gianni Biolo, 2024, izvirni znanstveni članek Povzetek: Hypokinesia triggers oxidative stress and accelerates the turnover of the glutathione system via the γ-glutamyl cycle. Our study aimed to identify the regulatory checkpoints controlling intracellular glutathione levels. We measured the intermediate substrates of the γ-glutamyl cycle in erythrocytes from 19 healthy young male volunteers before and during a 10-day experimental bed rest. Additionally, we tracked changes in glutathione levels and specific metabolite ratios up to 21 days of bed rest. Using gas chromatography-mass spectrometry and the internal standard technique, we observed a 9 ± 9% decrease in glutathione levels during the first 5 days of bed rest, followed by an 11 ± 9% increase from the 5th to the 10th day, nearly returning to baseline ambulatory levels. The cysteinyl-glycine-to-glutathione ratio, reflecting γ-glutamyl cyclotransferase activity (a key enzyme in glutathione breakdown), rose by 14 ± 22% in the first 5 days and then fell by 10 ± 14% over the subsequent 5 days, again approaching baseline levels. Additionally, the γ-glutamyl cysteine-to-cysteine ratio, indicative of γ-glutamyl cysteine synthetase activity (crucial for glutathione synthesis), increased by 12 ± 30% on day 5 and by 29 ± 41% on day 10 of bed rest. The results observed on day 21 of bed rest confirm those seen on day 10. By calculating the ratio of product concentration to precursor concentration, we assessed the efficiency of these key enzymes in glutathione turnover. These results were corroborated by directly measuring glutathione synthesis and degradation rates in vivo using stable isotope techniques. Our findings reveal significant changes in glutathione kinetics during the initial days of bed rest and identify potential therapeutic targets for maintaining glutathione levels.
Ključne besede: antioxidant, muscle unloading, glutathion turnover, γ-glutamyl cycle, gamma-glutamyl cycle
Objavljeno v DiRROS: 21.11.2024; Ogledov: 435; Prenosov: 1309
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10. Tensiomyography : from muscle assessment to talent identification toolDražen Čular, Matej Babić, Damir Zubac, Ana Kezić, Iva Macan, Leonardo Alexandre Peyré-Tartaruga, Francesco Ceccarini, Johnny Padulo, 2023, pregledni znanstveni članek Povzetek: Introduction: Tensiomyography (TMG) is a non-invasive and cost-effective tool that is gaining popularity in fields such as sports science, physical therapy, and medicine. In this narrative review, we examine the different applications of TMG and its strengths and limitations, including its use as a tool for sport talent identification and development. Methods: In the course of crafting this narrative review, an exhaustive literature search was carried out. Our exploration spanned several renowned scientific databases, such as PubMed, Scopus, Web of Science, and ResearchGate. The materials we sourced for our review included a broad spectrum of both experimental and non-experimental articles, all focusing on TMG. The experimental articles featured varied research designs including randomized controlled trials, quasi-experiments, as well as pre-post studies. As for the non-experimental articles, they encompassed a mix of case-control, cross-sectional, and cohort studies. Importantly, all articles included in our review were written in English and had been published in peer-reviewed journals. The assortment of studies considered provided a holistic view of the existing body of knowledge on TMG, and formed the basis of our comprehensive narrative review. Results: A total of 34 studies were included in the review, organized into three sections: 1) assessing muscle contractile properties of young athletes, 2) using TMG in the talent identification and development process and 3) Future research and perspectives. According to data presented here, the most consistent TMG parameters for determining muscle contractile properties are radial muscle belly displacement, contraction time, and delay time. Biopsy findings from the vastus lateralis (VL) confirmed TMG as a valid tool for estimating the ratio of myosin heavy chain (%MHC-I). Conclusion: TMGs ability to estimate the ratio of %MHC-I has the potential to aid in the selection of athletes with the muscle characteristics best suited for a particular sport, eliminating the need for more invasive procedures. However, more research is warranted to fully understand TMG’s potential and its reliability when used with young athletes. Importantly, the use of TMG technology in this process can positively impact health status, reducing the frequency and severity of injuries and the duration of recovery, and subsequently can reduce drop out rates among youth athletes. Future studies should look at twin youth athletes, as a model capable of discriminating between the influence of hereditary factors vs. environmental factors, in therms of muscle contractility and TMG’s potential for instance.
Ključne besede: muscle assessment, muscle fiber composition, noninvasive metthod, MHC ratio, TMG
Objavljeno v DiRROS: 20.11.2024; Ogledov: 383; Prenosov: 196
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