ORCID Profile
0000-0002-3322-0080
Current Organisations
University of Information Technology and Management in Rzeszow
,
Danylo Halytsky Lviv National Medical Univeristy
,
Deakin University
,
Queensland University of Technology
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Publications
Are we doing enough to identify and prioritise occupational carcinogens?
Publisher: BMJ
Date: 17-07-2018
Increases in muscle temperature by hot water improve muscle contractile function and reduce motor unit discharge rates
Publisher: Wiley
Date: 27-01-2023
DOI: 10.1111/SMS.14312
Abstract: Examine the effects of 42°C hot‐water immersion on muscle contraction function and motor unit discharge rates. Voluntary and evoked contraction assessments were examined first with a concomitant increase in the core and muscle temperature, and thereafter with increased muscle temperature but cooled core temperature. Fifteen participants (24.9 ± 5.6 years) performed neuromuscular assessments before, after, and ~15‐min after either 90‐min of 42°C (hot) or 36°C (control) water immersion. Maximal voluntary contraction (MVC) assessment of knee extension was performed along with surface electromyography (sEMG) ( vastus lateralis and medialis [VL, VM]) and voluntary activation level (VAL). Resting evoked twitch was elicited for peak torque and time to peak torque analysis. In addition, the VL and VM motor unit discharge rates (MUDR) were measured. After hot‐water immersion (core temperature ↑1°C muscle temperature ↑2.4°C), MVC torque and VAL decreased ( p 0.05). The sEMG (VL and VM) and peak twitch torque did not change ( p 0.05), while time to peak torque decreased ( p = 0.007). The VL and VM MUDR decreased, showing a time effect, after both water immersion conditions (36 and 42°C) ( p 0.001). Fifteen minutes after the hot‐water immersion (core temperature at baseline muscle temperature ↑1.4°C), MVC torque returned to baseline, but VAL remained lower. The sEMG (VL and VM) remained unchanged. Peak twitch torque increased ( p 0.002) and time to peak torque remained lower ( p = 0.028). The MUDR remained lower after both water immersion conditions ( p 0.05). Increased core temperature evoked by 42°C hot‐water immersion decreases MVC torque and VAL. However, a passive increase in muscle temperature improved evoked muscle contractile function (i.e., time to peak torque [after] and peak twitch torque [~15 min after]). Moreover, a passive increase in muscle temperature reduced the required MUDR to attain the same torque.
A passive increase in muscle temperature enhances rapid force production and neuromuscular function in healthy adults
Publisher: Elsevier BV
Date: 08-2021
Passive muscle stretching reduces estimates of persistent inward current strength in soleus motor units
Publisher: The Company of Biologists
Date: 2020
DOI: 10.1242/JEB.229922
Abstract: Prolonged (≥60 s) passive muscle stretching acutely reduces maximal force production at least partly through a suppression of efferent neural drive. The origin of this neural suppression has not been determined, however some evidence suggests that reductions in the litude of persistent inward currents (PICs) in the motoneurons may be important. The aim of the present study was to determine whether acute passive (static) muscle stretching affects PIC strength in gastrocnemius medialis (GM) and soleus (SOL) motor units. We calculated the difference in instantaneous discharge rates at recruitment and derecruitment (ΔF) for pairs of motor units in GM and SOL during triangular isometric plantar flexor contractions (20% maximum) both before and immediately after a 5-min control period and immediately after five 1-min passive plantar flexor stretches. After stretching there was a significant reduction in SOL ΔF (−25.6% 95%CI=−45.1 to −9.1 %, p=0.002) but not GM ΔF. These data suggest passive muscle stretching can reduce the intrinsic excitability, via PICs, of SOL motor units. These findings (1) suggest that PIC strength might be reduced after passive stretching, (2) are consistent with previously-established post-stretch decreases in SOL but not GM EMG litudes during contraction, and (3) indicate that reductions in PIC strength could underpin the stretch-induced force loss.
Facilitation–inhibition control of motor neuronal persistent inward currents in young and older adults
Publisher: Wiley
Date: 03-11-2022
DOI: 10.1113/JP283708
Abstract: A well‐coordinated facilitation–inhibition control of motor neuronal persistent inward currents (PICs) via diffuse neuromodulation and local inhibition is essential to ensure motor units discharge at required times and frequencies. Present best estimates indicate that PICs are reduced in older adults however, it is not yet known whether PIC facilitation–inhibition control is also altered with ageing. We investigated the responses of PICs to (i) a remote handgrip contraction, which is believed to diffusely increase serotonergic input onto motor neurones, and (ii) tendon vibration of the antagonist muscle, which elicits reciprocal inhibition, in young and older adults. High‐density surface electromyograms were collected from soleus and tibialis anterior of 18 young and 26 older adults during triangular‐shaped plantar and dorsiflexion contractions to 20% (handgrip experiments) and 30% (vibration experiments) of maximum torque (rise‐decline rate of 2%/s). A paired‐motor‐unit analysis was used to calculate ∆ F , which is assumed to be proportional to PIC strength. Δ F increased in both soleus (0.55 peaks per second (pps), 16.0%) and tibialis anterior (0.42 pps, 11.4%) after the handgrip contraction independent of age. Although antagonist tendon vibration reduced Δ F in soleus (0.28 pps, 12.6%) independent of age, less reduction was observed in older (0.42 pps, 10.7%) than young adults (0.72 pps, 17.8%) in tibialis anterior. Our data indicate a preserved ability of older adults to lify PICs following a remote handgrip contraction, during which increased serotonergic input onto the motor neurones is expected, in both lower leg muscles. However, PIC deactivation in response to reciprocal inhibition was impaired with ageing in tibialis anterior despite being preserved in soleus. image Motor neuronal persistent inward currents (PICs) are facilitated via diffuse neuromodulation and deactivated by local inhibition to ensure motor units discharge at required times and frequencies, allowing normal motor behaviour. PIC litudes appear to be reduced with ageing however, it is not known whether PIC facilitation–inhibition control is also altered. Remote handgrip contraction, which should diffusely increase serotonergic input onto motor neurones, facilitated PICs similarly in both soleus and tibialis anterior of young and older adults. Antagonist tendon vibration, which induces reciprocal inhibition, reduced PICs in soleus in both young and older adults but had less effect in tibialis anterior in older adults. Data from lower‐threshold motor units during low‐force contractions suggest that PIC facilitation is preserved with ageing in soleus and tibialis anterior. However, the effect of reciprocal inhibition on the contribution of PICs to motor neurone discharge seems reduced in tibialis anterior but preserved in soleus.
Synthesis, antibacterial and antifungal activity of new 3-aryl-5h-pyrrolo[1,2-a]imidazole and 5h-imidazo[1,2-a] azepine quaternary salts
Publisher: MDPI AG
Date: 13-07-2021
DOI: 10.3390/MOLECULES26144253
Abstract: A series of novel 3-aryl-5H-pyrrolo[1,2-a]imidazole and 5H-imidazo[1,2-a]azepine quaternary salts were synthesized in 58–85% yields via the reaction of 3-aryl-6, 7-dihydro-5H-pyrrolo[1,2-a]imidazoles or 3-aryl-6,7,8,9-tetrahydro-5H-imidazo[1,2-a]azepines and various alkylating reagents. All compounds were characterized by 1H NMR, 13C NMR, and LC-MS. The conducted screening studies of the in vitro antimicrobial activity of the new quaternary salts derivatives established that 15 of the 18 newly synthesized compounds show antibacterial and antifungal activity. Synthesized 3-(3,4-dichlorohenyl)-1-[(4-phenoxyphenylcarbamoyl)-methyl]-6,7-dihydro-5H-pyrrolo[1,2-a]imidazol-1-ium chloride 6c possessed a broad activity spectrum towards Staphylococcus aureus, Escherichia coli, Klebsiella pneumoniae, Acinetobacter baumannii, and Cryptococcus neoformans, with a high hemolytic activity against human red blood cells and cytotoxicity against HEK-293. However, compound 6c is characterized by a low in vivo toxicity in mice (LD50 2000 mg/kg).
Looking at the bigger PICture: understanding and counteracting the decline of persistent inward currents in older adults
Publisher: Wiley
Date: 16-11-2021
DOI: 10.1113/JP282370
Passive muscle stretching reduces estimates of persistent inward current strength in soleus motor units
Publisher: Cold Spring Harbor Laboratory
Date: 02-08-2020
DOI: 10.1101/2020.07.31.230029
Abstract: Prolonged (≥60 s) passive muscle stretching acutely reduces maximal force production at least partly through a suppression of efferent neural drive. The origin of this neural suppression has not been determined, however some evidence suggests that reductions in the litude of persistent inward currents (PICs) in the motoneurons may be important. The aim of the present study was to determine whether acute passive (static) muscle stretching affects PIC strength in gastrocnemius medialis (GM) and soleus (SOL) motor units. We calculated the difference in instantaneous discharge rates at recruitment and derecruitment (ΔF) for pairs of motor units in GM and SOL during triangular isometric plantar flexor contractions (20% maximum) both before and immediately after a 5-min control period and immediately after five 1-min passive plantar flexor stretches. After stretching there was a significant reduction in SOL ΔF (−25.6% 95%CI = -45.1 to -9.1 %, p=0.002) but not GM ΔF. These data suggest passive muscle stretching can reduce the intrinsic excitability, via PICs, of SOL motor units. These findings (1) suggest that PIC strength might be reduced after passive stretching, (2) are consistent with previously-established post-stretch decreases in SOL but not GM EMG litudes during contraction, and (3) indicate that reductions in PIC strength could underpin the stretch-induced force loss. Motoneurons require an lification mechanism to operate within the firing frequencies observed during normal motor behaviour. Here we present evidence that this lification mechanism is reduced after passive muscle stretching.
Effects of resistance training, detraining, and retraining on strength and functional capacity in elderly.
Publisher: Springer Science and Business Media LLC
Date: 17-05-2019
DOI: 10.1007/S40520-018-0970-5
Abstract: The interruption of training (detraining) results in loss of the gains acquired. Partial retention could occur after detraining, and variation in training stimuli may optimize retraining adaptations. To evaluate the effect of a resistance-retraining program on strength and functional capacity performance after a detraining period. Ten elderly men and women (63-68 years) completed 12 weeks of training, 16 weeks of detraining, and 8 weeks of retraining. One-repetition maximum (1-RM) at 45° leg press, maximum isometric knee extension torque, rate of torque development (RTD), 30-s sit-to-stand, timed up and go, and stair ascent and descent tests were assessed. The 1-RM increased after training (p < 0.01) and remained higher after a detraining period when compared to pre-training (p 0.05). For RTD and 30-s sit-to-stand, there was an increase after retraining when compared to pre-training values (p < 0.05). For timed up and go and stair ascent and descent, reductions were observed between pre-training and post-training periods (p < 0.05), only timed up and go increased after the detraining period (p < 0.01). After 16 weeks of detraining, the maximum strength did not return to baseline levels, and a retraining with explosive strength exercise sessions can recover maximum strength gains, RTD, and functional capacity at the same level obtained after a detraining period. The inclusion of an explosive strength session in retraining period improves RTD and 30-s sit-to-stand performance and can accelerate the recovery of strength after a detraining period.
Synthesis, antibacterial and antifungal activity of new 3-biphenyl-3H-Imidazo[1,2-a]azepin-1-ium bromides
Publisher: Elsevier BV
Date: 09-2020
Related Organisations
University Of Information Technology And Management In Rzeszow
Location: Poland
Related Funding Activities
No related grants have been discovered for Roman Lesyk.