Bioelectrical Changes Research Articles

From the Microbiome to the Electrome: Implications for the Microbiota-Gut-Brain Axis.

The gut microbiome plays a fundamental role in metabolism, as well as the immune and nervous systems. Microbial imbalance (dysbiosis) can contribute to subsequent physical and mental pathologies. As such, interest has been growing in the microbiota-gut-brain brain axis and the bioelectrical communication that could exist between bacterial and nervous cells. The aim of this study was to investigate the bioelectrical profile (electrome) of two bacterial species characteristic of the gut microbiome: a Proteobacteria Gram-negative bacillus Escherichia coli (E. coli), and a Firmicutes Gram-positive coccus Enterococcus faecalis (E. faecalis). We analyzed both bacterial strains to (i) validate the fluorescent probe bis-(1,3-dibutylbarbituric acid) trimethine oxonol, DiBAC4(3), as a reliable reporter of the changes in membrane potential (Vmem) for both bacteria; (ii) assess the evolution of the bioelectric profile throughout the growth of both strains; (iii) investigate the effects of two neural-type stimuli on Vmem changes: the excitatory neurotransmitter glutamate (Glu) and the inhibitory neurotransmitter γ-aminobutyric acid (GABA); (iv) examine the impact of the bioelectrical changes induced by neurotransmitters on bacterial growth, viability, and cultivability using absorbance, live/dead fluorescent probes, and viable counts, respectively. Our findings reveal distinct bioelectrical profiles characteristic of each bacterial species and growth phase. Importantly, neural-type stimuli induce Vmem changes without affecting bacterial growth, viability, or cultivability, suggesting a specific bioelectrical response in bacterial cells to neurotransmitter cues. These results contribute to understanding the bacterial response to external stimuli, with potential implications for modulating bacterial bioelectricity as a novel therapeutic target.

In-Season Longitudinal Hydration/Body Cell Mass Ratio Changes in Elite Rugby Players.

Hydration status has a direct role in sports performance. Bioelectrical Impedance Vector Analysis (BIVA) and Urine Specific Gravity (USG) are commonly used to assess hydration. The study aims to identify the sensitivity and relationship between BIVA and USG in a field sports setting. BIVA and USG measurements were conducted five times throughout one rugby season. 34 elite male rugby players (25.1 ± 4.4 years; 184.0 ± 7.8 cm; 99.9 ± 13.4 kg) were enrolled. Differences over time were tested using one-way repeated measures ANOVA, and Bonferroni's post-hoc test was applied in pairwise comparisons. Resistance-reactance graphs and Hotelling's T2 test were used to characterize the sample and to identify bioelectrical changes. A repeated measures correlation test was conducted for BIVA-USG associations. Two clear trends were seen: (1) from July to September, there was a vector shortening and an increase of the phase angle (p < 0.001); and (2) from December to April, there was a vector lengthening and a decrease of the phase angle (p < 0.001). USG reported neither changes nor correlation with BIVA longitudinally (p > 0.05). Vector variations indicated a body fluid gain (especially in the intracellular compartment) and a body cell mass increase during the preseason, suggesting a physical condition and performance improvement. During the last months of the season, the kinetic was the opposite (fluid loss and decreased body cell mass). Results suggested that BIVA is sensitive to physiological changes and a better option than USG for assessing hydration changes during a rugby sports season.

The aggressiveness of succinate dehydrogenase subunit B-deficient chromaffin cells is reduced when their bioelectrical properties are restored by glibenclamide.

Pheochromocytomas/paragangliomas (PPGLs) are neuroendocrine tumours, mostly resulting from mutations in predisposing genes. Mutations of succinate dehydrogenase (SDH) subunit B (SDHB) are associated with high probability of metastatic disease. Since bioelectrical properties and signalling in cancer are an emerging field, we investigated the metabolic, functional and electrophysiological characteristics in human succinate dehydrogenase subunit B (SDHB)-deficient pheochromocytoma cells. These cells exhibited reduced SDH function with elevated succinate-to-fumarate ratio and reduced intracellular ATP levels. The analysis of membrane passive properties revealed a more hyperpolarized membrane potential and a lower cell capacitance of SDHB-deficient cells compared to the parental ones. These bioelectrical changes were associated with reduced proliferation and adhesion capacity of SDHB-deficient cells. Only in SDHB-deficient cells, we also observed an increased amplitude of potassium currents suggesting an activation of ATP-sensitive potassium channels (KATP). Indeed, exposure of the SDHB-deficient cells to glibenclamide, a specific KATP inhibitor, or to ATP caused normalization of potassium current features and altered proliferation and adhesion. In this work, we show for the first time that reduced intracellular ATP levels in SDHB-deficient chromaffin cells impaired cell bioelectrical properties, which, in turn, are associated with an increased cell aggressiveness. Moreover, we first ever demonstrated that glibenclamide not only reduced the outward potassium currents in SDHB-deficient cells but increased their growth capacity, reduced their ability to migrate and shifted their phenotype towards one more similar to that of parental one.

ANALYSIS OF BIOELECTRIC CHANGES IN THE NERVE – MUSCULAR COMPLEX UNDER THE CONDITIONS OF SHOCK WAVE INFLUENCE

Abstract. Recently, multimodal neurophysiological monitoring has been widely implemented in medical practice, thanks to which a powerful diagnostic base, additional possibilities of intensive therapy, surgical treatment and signifi cant improvement of its results are provided.In our experiment, as a result of the analysis of bioelectrical changes in the neuromuscular complex under the conditions of shock wave exposure, distinct changes in the functioning of the neuromuscular complex were observed, which were manifested in an increase in the excitation threshold under conditions of both direct and indirect stimulation of the calf muscle, reduction of the latent period and chronaxia with indirect stimulation and increase in the amplitude of the action potential. Blast injury leads to changes in refractoriness phases, there is a signifi cant increase in the amplitude of the action potential in response to the second stimulus. Under the conditions of simulation of the action of the shock wave, reliable changes in the conditioned bioelectric activity of the calf muscle develop, which is manifested in increased excitability, a decrease in the degree of synchronization of the response of the muscle under study, and a slowing of its response to indirect stimulation.On the day of the explosive injury, a more than two-fold increase in the amplitude of the evoked response of the calf muscle was observed, after a week this indicator showed a tendency to normalize, and after two weeks of the model’s existence it was only 140 % of the average value in the control group.Progressive changes in the bioelectrical activity of the neuromuscular apparatus reach a maximum after one week and do not level off completely after two weeks after the injury. In addition, primary damage, such as microvascular damage and neuroinfl ammation, do not play a major role in the occurrence of neurophysiological disorders, as they are present only in the initial period after the injury, but almost disappear after fourteen days.

Barley systemic bioelectrical changes detect pathogenic infection days before the first disease symptoms

Plant electrome corresponds to the emergent set of plant bioelectrical activity. The infection of plant tissues by different fungi alters this bioelectrical activity and can originate different electrical signatures, which can be used to identify the potential pathogenic agent. In this work, we evaluated the systemic variations of the electrome of barley triggered by the inoculation of Blumeria graminis and Bipolaris sorokiniana on the leaves. Therefore, approximately 50 days-old barley plants were placed within a Faraday cage under controlled conditions. A pair of needle electrodes was inserted in the culm for the recording of bioelectrical data. The plants were then inoculated with the pathogen in the last completely expanded leaf. Each pathogen was inoculated in different plants. Plants exposed to the same procedures as the inoculated ones, but without the fungi, served as controls. The electromes were recorded through 48 h, 24 h of which before the fungi inoculation or the control treatment. The bioelectrical data collected were analysed as time series through the following techniques: descriptive statistics, Bayesian change point (BCP) analysis, approximate entropy (ApEn), and autocorrelation. The results of these analyses were used as features, hence creating the dataset used in the machine learning (cluster analysis). The results indicate that the inoculation of pathogenic fungi culminated in a greater electrome variation (EV) when compared with the control (simulated inoculation). The pathogen inoculation generated peculiarities in the EV distribution for each pathogen. Therefore, the inoculation of B. graminis or B. sorokiniana created an electrical signature specific for each pathogen. This signature allows identifying the presence of pathogenic infection in the first minutes after contact with the host surface.

Effects of Electrode Relocation on Bioelectrical Impedance Measurements on Potato Tissue

The measurement of bioelectrical impedance is a non-destructive technique that is being used to assess the quality of fruits and plants. Applications of this technique assume that changes in the values of bioelectrical impedance are only due to changes in the tissues under study. This paper evaluates the bioelectrical impedance changes associated to changing the location of the measurement electrodes using an electrode fixture that keeps their distance constant. Due to the short period of time in which these measurements take place, the tissue should have not changed and therefore the measured impedance values should remain constant. This research reports changes in the values of low-frequency resistance as high as 15 %, changes in the values of high-frequency resistance as high as 39 % and changes in the Cole-Cole frequency as high as 16 %. Being these changes in the same order of magnitude, or even larger than changes in bioelectrical impedance reported in the literature for practical applications of the technique, one needs to exercise extreme caution at the time of interpreting similar results in the practical applications of this technique and extracting conclusions.

Electromyographic features of the perineum and pelvic floor in patients with an artificial bladder

Aim – to assess the electromyographic features of the pelvic floor muscles and the sphincter apparatus in patients who underwent radical cystprostatectomy with the formation of an artificial bladder.The main study group consisted of 57 patients with muscle invasive bladder cancer who underwent a standard radical cystprostatectomy with ileocystoplasty. The study of the pelvic floor muscular bioelectric activity with computed electromyography (EMG) of the sphincter apparatus of the pelvic organs was carried out on a 2-channel computer electromyograph "NeuroTrac ™ MyoPlus4". The obtained results of the study of the bioelectric activity of the pelvic floor muscles showed a decrease in the amplitude of contractions in the Work Average mode by 42.1% (p≤0.001) for the perineal electrode, and by 35.7% (p≤0.05) for the rectal electrode, compared with the control group, which indicates a low contractility of the muscular diaphragm of the pelvis and may cause incontinence in patients with an artificial bladder. The average deviation over the entire duration of the session in Work mode in the group of patients with neobladder in channels A and B was 2.3 (p≤0.05) and 1.9 (p≤0.05) times higher, respectively, compared with control group. These data indicate an imbalance in the muscle tone of the pelvic floor in patients after extensive reconstructive intervention on the pelvic organs and can potentiate urodynamic disorders in the study group of patients. The average amplitude (Rest Average) of the activity of biopotentials in the resting state of the pelvic floor muscles along channels A and B is higher by 42.4% and 47.6% (p≤0.05), in comparison with the control group, which indicates insufficient relaxation and rest of striated muscles and sphincter. Despite the change in bioelectric potentials from the rectal electrode in the study group of patients, there were no signs of functional insufficiency of the anal sphincter, in contrast to the severity of urinary incontinence, which correlated and corresponded to the results of bioelectrical changes obtained through channels A and B, up to oscillations and loss of complete control. The EMG analysis of the pelvic floor muscles revealed characteristic changes in the biopotentials of the pelvic sphincters and indicated their relationship with the clinical features of the rehabilitation of this group of patients and the prospect of including the biofeedback method. It is a derivative form of the electromyographic signal in the treatment of incontinence in patients with neobladder.

Fractal Dimension as Quantifier of EEG Activity in Driving Simulation

Dynamical systems and fractal theory methodologies have been proved useful for the modeling and analysis of experimental datasets and, in particular, for electroencephalographic signals. The computation of the fractal dimension of approximation curves in the plane enables the assignment of numerical values to bioelectric recordings in order to discriminate between different states of the observed system. The procedure does not require the stationarity of the signals nor extremely long segments of data. In previous works, we checked that this parameter is a good index for brain activity. In this paper, we consider this measurement in order to quantify the geometric complexity of the brain waves in states of rest and during vehicle driving simulation in different scenarios. This work presents evidence that the fractal dimension allows the detection of the brain bioelectric changes produced in the areas that carry out the different driving simulation tasks, increasing with their complexity.

Changes in blood circulation and the central nervous system functions in 4–10 year children with visual impairment

Introduction. Visual impairment is the most common disturbances during the child development in preschool and primary school age. Such children need care with the health-improving technology based on scientific knowledge about the characteristics of their psychophysiological functions. The aim of the study is to identify development-related changes in blood circulation and central nervous system functions in 4-10 year healthy children and cases with visual impairments. Materials and methods. A total of 380 children were examined by electrocardiography, electroencephalography, registration of neurodynamic processes, analysis of the tactile function, and self-assessment of anxiety. Results. In subjects with visual impairment, an increase in age-related heterochronism in the development of psychophysiological functions was revealed. The accuracy indices of time intervals and tactile sensitivity of the skin of the fingers were higher, and the indices of physical development, kinematometry, and mobility of nervous processes in many age groups are lower than in healthy ones. Such adaptive changes were accompanied by an increase in functional stress. So, for example, in preschool children from 4 to 6 years, when analyzing the structure of the heart rhythm, an increase in the values of the stress index was noted (from 148.08 ± 3.32 to 220.08 ± 3.62 c.u.; p &lt; 0.05). Conclusion. Judging by the high values of activity indices of the central mechanisms of heart rhythm regulation, anxiety, and the nature of bioelectric changes on the EEG, the “price” of age-related adaptation in children with sensory impairments rises. It contributes to the development of disadaptation. The conclusion is made about the need to develop effective means of psychophysical correction of children with visual impairments, taking into account the nature of age-related changes.

Bistability of somatic pattern memories: stochastic outcomes in bioelectric circuits underlying regeneration.

Nervous systems' computational abilities are an evolutionary innovation, specializing and speed-optimizing ancient biophysical dynamics. Bioelectric signalling originated in cells' communication with the outside world and with each other, enabling cooperation towards adaptive construction and repair of multicellular bodies. Here, we review the emerging field of developmental bioelectricity, which links the field of basal cognition to state-of-the-art questions in regenerative medicine, synthetic bioengineering and even artificial intelligence. One of the predictions of this view is that regeneration and regulative development can restore correct large-scale anatomies from diverse starting states because, like the brain, they exploit bioelectric encoding of distributed goal states-in this case, pattern memories. We propose a new interpretation of recent stochastic regenerative phenotypes in planaria, by appealing to computational models of memory representation and processing in the brain. Moreover, we discuss novel findings showing that bioelectric changes induced in planaria can be stored in tissue for over a week, thus revealing that somatic bioelectric circuits in vivo can implement a long-term, re-writable memory medium. A consideration of the mechanisms, evolution and functionality of basal cognition makes novel predictions and provides an integrative perspective on the evolution, physiology and biomedicine of information processing in vivo. This article is part of the theme issue 'Basal cognition: multicellularity, neurons and the cognitive lens'.

ELECTROENCEPHALOGRAPHIC MARKERS OF LATERAL SHIFTS OF BRAIN MIDLINE STRUCTURES IN PATIENTS WITH ACUTE SPONTANEOUS SUPRATENTORIAL INTRACEREBRAL HAEMORRHAGE

The aim of this study is to improve the diagnostic approaches in acute period of spontaneous supratentorial intracerebral hemorrhage by detecting the most informative parameters of spectral analysis of the electroencephalographic pattern in the evaluation of cerebral bioelectrical activity changes caused by the lateral shifts of brain midline structures. Materials and methods. We carried out clinical and paraclinical examination of 156 patients (90 men and 66 women, mean age 66,7±0,8 years) with firstly appeared hypertensive spontaneous supratentorial intracerebral hemorrhage. The diagnosis was based on the findings of computed tomography. Lateral shift was evaluated as an average from septum pellucidum and pineal gland displacements. Clinical neurological investigation included the evaluation according to the National Institute of Health Stroke Scale. Computed electroencephalography was carried out within the first 48 hours from the disease onset. Spectral rhythm power, fronto-occipital gradients, interhemispheric rhythm asymmetry parameters were analyzed. Statistical processing included evaluating differences between the groups studied, logistic regression analysis, ROC-analysis. Results. No lateral shift of brain midline structure was found in 57 (36.5%) patients; lateral shift ranged from 1-5mm was diagnosed in 72 (46.2%) patients; the lateral shift over 5 mm was found in 27 (17.3%) patients. We have found out the following values can be used as electroencephalographic criteria of lateral shift of brain midline structures: values of relative spectral power rhythm of alpha band ≤20,5% in affected hemisphere (Se=79,8%, Sp=77,2%) and ≤17,7% in intact hemisphere (Se=71,7%, 75,4%), fronto-occipital rhythm gradients of alpha2 band &gt;–0,085 in affected hemisphere (Se=71,7%, Sp=63,2%) and &gt;–0,266 in intact hemisphere (Se=80,8%, Sp=54,4%), while relative spectral rhythm power of delta band &gt;48,4% in affected hemisphere (Se=88,9%, Sp=74,2%) and &gt;46,8% in intact hemisphere (Se=92,6%, Sp=72,4%), fronto-occipital rhythm gradients of alpha band &gt;–0,001 in affected hemisphere (Se=81,5%, Sp=65,1%). These values demonstrate disturbances in cerebral bioelectrical activity caused by lateral shift over 5 mm. Conclusions. The values of relative spectral rhythm power and fronto-occipital rhythm gradients of alpha band in affected and intact hemispheres are the most informative parameters of spectral electroencephalographic pattern analysis for detection of bioelectrical brain activity deteriorations caused by the lateral shift of brain midline structure due to acute spontaneous supratentorial intracerebral haemorrhage.

Electrochemical gradients are involved in regulating cytoskeletal patterns during epithelial morphogenesis in the Drosophila ovary

BackgroundDuring Drosophila oogenesis, the follicular epithelium differentiates into several morphologically distinct follicle-cell populations. Characteristic bioelectrical properties make this tissue a suitable model system for studying connections between electrochemical signals and the organisation of the cytoskeleton. Recently, we have described stage-specific transcellular antero-posterior and dorso-ventral gradients of intracellular pH (pHi) and membrane potential (Vmem) depending on the asymmetrical distribution and/or activity of various ion-transport mechanisms. In the present study, we analysed the patterns of basal microfilaments (bMF) and microtubules (MT) in relation to electrochemical signals.ResultsThe bMF- and MT-patterns in developmental stages 8 to 12 were visualised using labelled phalloidin and an antibody against acetylated α-tubulin as well as follicle-cell specific expression of GFP-actin and GFP-α-tubulin. Obviously, stage-specific changes of the pHi- and Vmem-gradients correlate with modifications of the bMF- and MT-organisation. In order to test whether cytoskeletal modifications depend directly on bioelectrical changes, we used inhibitors of ion-transport mechanisms that have previously been shown to modify pHi and Vmem as well as the respective gradients. We inhibited, in stage 10b, Na+/H+-exchangers and Na+-channels with amiloride, V-ATPases with bafilomycin, ATP-sensitive K+-channels with glibenclamide, voltage-dependent L-type Ca2+-channels with verapamil, Cl−-channels with 9-anthroic acid and Na+/K+/2Cl−-cotransporters with furosemide, respectively. The correlations between pHi, Vmem, bMF and MT observed in different follicle-cell types are in line with the correlations resulting from the inhibition experiments. While relative alkalisation and/or hyperpolarisation stabilised the parallel transversal alignment of bMF, acidification led to increasing disorder and to condensations of bMF. On the other hand, relative acidification as well as hyperpolarisation stabilised the longitudinal orientation of MT, whereas alkalisation led to loss of this arrangement and to partial disintegration of MT.ConclusionsWe conclude that the pHi- and Vmem-changes induced by inhibitors of ion-transport mechanisms simulate bioelectrical changes occurring naturally and leading to the cytoskeletal changes observed during differentiation of the follicle-cell epithelium. Therefore, gradual modifications of electrochemical signals can serve as physiological means to regulate cell and tissue architecture by modifying cytoskeletal patterns.

Relative study between the exposures of 6MeV photons and 0.3 mT-50 Hz magnetic fields in rat's liver

Effect of 0.3mT-50Hz magnetic field exposure on rats' liver dielectric relaxation was studied. Animals were exposed similar to occupational workers 8h/day for periods from 1 to 4 weeks the exposure effects were monitored relative to the effect of exposure to high energy 6MeV standard dose of 1 rad. Dielectric relaxations in frequency range up to 8MHz carried out immediately for all animals from each group to examine bioelectrical changes in liver relative permittivity, conductivity, and dielectric loss. The results indicated significant difference in dielectric characteristics due to the counter-ion diffusion at frequency up to 1MHz, whereas frequency increased the shift unremarkably noticed. Unveil to the data of relative fraction of damage (RFD), it insight remarkable damage due to magnetic fields in a manner it should not be less important than high energy photons. Significantly, animals of 1 week magnetic field exposure showed maximum damage effect by 15%, 26% and 5% damage in relative permittivity, conductivity and dielectric loss respectively more than 6MeV photons exposure. Relative to unexposed group the samples from 1 week magnetic field exposure confirmed liver bioimpedance results and indicated significant increase in enzymatic levels by 20.6%, 17.1%, 3.32% and 13.1% for SGOT, SGPT, TP and MDA respectively. The former results may reflect the animal body self-adaptation as exposure period increased. It is worthy to mention that this work is an important one that correlates between the effects of both extremely low frequency fields and ionizing radiation.

Current State and Future Prospects of EEG and fNIRS in Robot-Assisted Gait Rehabilitation: A Brief Review.

Gait and balance impairments are frequently considered as the most significant concerns among individuals suffering from neurological diseases. Robot-assisted gait training (RAGT) has shown to be a promising neurorehabilitation intervention to improve gait recovery in patients following stroke or brain injury by potentially initiating neuroplastic changes. However, the neurophysiological processes underlying gait recovery through RAGT remain poorly understood. As non-invasive, portable neuroimaging techniques, electroencephalography (EEG) and functional near-infrared spectroscopy (fNIRS) provide new insights regarding the neurophysiological processes occurring during RAGT by measuring different perspectives of brain activity. Due to spatial information about changes in cortical activation patterns and the rapid temporal resolution of bioelectrical changes, more features correlated with brain activation and connectivity can be identified when using fused EEG-fNIRS, thus leading to a detailed understanding of neurophysiological mechanisms underlying motor behavior and impairments due to neurological diseases. Therefore, multi-modal integrations of EEG-fNIRS appear promising for the characterization of neurovascular coupling in brain network dynamics induced by RAGT. In this brief review, we surveyed neuroimaging studies focusing specifically on robotic gait rehabilitation. While previous studies have examined either EEG or fNIRS with respect to RAGT, a multi-modal integration of both approaches is lacking. Based on comparable studies using fused EEG-fNIRS integrations either for guiding non-invasive brain stimulation or as part of brain-machine interface paradigms, the potential of this methodologically combined approach in RAGT is discussed. Future research directions and perspectives for targeted, individualized gait recovery that optimize the outcome and efficiency of RAGT in neurorehabilitation were further derived.

Diagnostic value of the integral assessment of electroencephalographic pattern in patients in the acute period of spontaneous supratentorial intracerebral hemorrhage

The main purpose of the study was to verify the diagnostic informative value of the integral evaluation of the electroencephalographic pattern in patients with spontaneous supratentorial intracerebral hemorrhage (SSICH) on the basis of the comparison of brain activity changes with clinical and neuroimaging data. Material and methods. Prospective cohort study of 46 patients in acute period of SSICH was conducted. It included complex clinical (using Glasgow Coma Scale, Full Outline of UnResponsiveness (FOUR) score, National Institute of Health Stroke Scale, Intracerebral hemorrhage score) and neuroimaging estimation of cerebral injury severity in the onset of the disease. Investigation of brain bioelectrical activity was made during fist 24–48 hours from the onset with determination of average absolute spectral rhythm power (AASRP), relative spectral rhythm power (RSRP), fronto-occipital rhythm gradient (FORG) in the affcted hemisphere (AH) and intact hemisphere (IH), interhemispheric rhythm asymmetry values. Results. On the basis of cluster analysis 2 types of the brain bioelectric activity changes were identifid in patients with SSICH. Type I of EEG pattern was registered in 56.5 % patients, it was characterized by ipsilateral increase of RSRP of δ-range with the dominance of θ-range rhythms in slow-wave activity structure in combination with smoothing of zonal diffrences of α-range rhythms in AH, whereas type II was characterized by bilateral domination of the RSRP δ-range with an accent in IH in combination with FORG inversion of α-range due to elevation of the α2-subrange in the anterior areas of IH. The patients with type II of EEG pattern were characterized by ipsilateral increase of RSRP of δ-range with the dominance of θ-range rhythms in slow-wave activity structure in combination with smoothing of zonal diffrences of α-range rhythms in AH. The patients with type II of EEG pattern were characterized by more severe brain impairment (ICH score 3 (2; 4) versus 0 (0; 1), P 14). Conclusions. Complex analysis of bioelectric activity of the brain in patients with SSICH allows to identify the integral types of EEG pattern, which represent the functional state of cerebral structures and are associated with the clinical and neuroimaging criteria of midline shift severity.

Generation of action potential-type changes in response to darkening and illumination as indication of the plasma membrane proton pump status in Marchantia polymorpha

The aim of the present study was to characterise bioelectrical changes in the membrane potential of Marchantia polymorpha gametophyte cells after light/dark transitions and to determine the role of the proton pump and energy status of the M. polymorpha cells in generation of these changes. Darkening caused persistent depolarisation of the resting potential (RP) and generation of short-lasting potential changes that were not uniform among different thalli. In some plants (18%), the changes evoked by darkening were typical action potentials (APsdark), whereas in 69% of the plants, the changes had a form of action potential-like responses (APsdark-like) consisting of a transient depolarisation followed by a plateau phase, whose magnitude and duration were inconstant. The illumination of the M. polymorpha always evoked action potentials (APslight) if the thallus was illuminated with light intensity of at least 120 µmol photons m−2 s−1 after 30-min darkening. To analyse the involvement of H+-ATPase in formation of the illumination/darkening-induced electrical responses in M. polymorpha, the proton pump regulators were used. The proton pump inhibitor (20 µM FCCP) significantly diminished the RP and inhibited dark-induced APdark and/or APdark-like responses and illumination-induced APslight. After application of DCMU (20 µM), the RP was strongly depolarised and no response to light/dark was observed. Fusicoccin (20 µM), i.e., an activator of the proton pump, strongly hyperpolarised the membrane potential and blocked dark-induced APdark/APdark-like responses and illumination-induced APslight.

An electrical bio-chip to transfer and detect electromagnetic stimulation on the cells based on vertically aligned carbon nanotubes

A highly sensitive impedimetric bio-chip based on vertically aligned multiwall carbon nanotubes (VAMWCNTs), was applied in direct interaction with lung cancer cells. Our tool provided both inducing and monitoring the bioelectrical changes in the cells initiated by electromagnetic (EM) wave stimulation. EM wave of 940MHz frequency with different intensities was used. Here, wave ablation might accumulate electrical charge on the tips of nanotubes penetrated into cell's membrane. The charge might induce ionic exchanges into the cell and cause alterations in electrical states of the membrane. Transmembrane electrostatic/dynamic states would be strongly affected due to such exchanges. Our novel modality was that, the cells' vitality changes caused by charge inductions were electrically detected with the same nanotubes in the architecture of electrodes for impedance measurement. The responses of the sensor were confirmed by electron and florescent microscopy images as well as biological assays. In summation, our method provided an effective biochip for enhancing and detecting external EM stimulation on the cells useful for future diagnostic and therapeutic applications, such as wave-guided drug-resistance breakage.

CARACTERISTICS OF TIME AND FREQUENCY EEG PATTERN IN CHILDREN AND ADOLESCENTS LIVING IN THE NORTH IN DIFFERENT AGE PERIODS

Features of CNS development have been investigated in children and adolescents living under the severe ecological conditions in the North of Russia. The original method for estimating a time structure of the EEG frequency components interrelations was used to study the dynamics of maturation of bioelectrical brain activity pattern and age-related changes of the interplay between the main EEG rhythms. It was found that the statistical structure of the interaction of the frequency components of EEG is undergoing a significant restructuring with age and has certain topography and gender differences. The period from 7 to 18 years of age is marked by decrease the probability of interaction of wave components of the main EEG frequency bands with components of delta and theta bands while simultaneously increasing interaction with the components of beta and alpha2 frequency bands. The dynamics of studied indices EEG manifested in the parietal, temporal and occipital regions of the cerebral cortex to the greatest extent. The largest sex-related differences in the EEG parameters occur in puberty. Functional core of the wave components interaction that maintain the structure of the frequency-temporal EEG pattern is formed to 16-18 years in girls in alpha2-beta1 range, while in boys - in alpha1-alpha2 range. Intensity of age-related rearrangements of the EEG pattern reflects the gradual maturation of electrogenesis in different brain structures and has individual features due to both genetic and environmental factors. Obtained quantitative indicators of formation with age of dynamic relationships between basic EEG rhythms permit to reveal children with disturbed or delayed development of the central nervous system.

FUNCTIONAL RE-MODELING INFLUENCE OF EPILEPS IN BRAIN TUMOR

Pathological electrical activity in proximity as well as distant cortical and subcortical zones induced by brain tumors alter the functioning of higher regulatory centers. These bioelectric changes in intricately connected brain functional zones lead to misbalances in compensatory mechanisms in turn influencing unfavorable disease outcome. Objective. This study is aimed at analyzing electroencephalographic (EEG) spectral peculiarities of as well as the peculiarities of cardiac rhythm variability in patients with epilepsy associated brain tumors. Materials and Methods. 72 patients participated in the survey aged from 22 to 83 years, divided into 2 groups: Brain tumor patients with epileptic seizures and brain tumor patients without seizures. The patients included in the study were those admitted to the neurosurgical department at Ryazan state regional hospital. Statistical, geometric and spectral parameters of heart rate variability as well as coherence and cross-correlational EEG analyses used to access the functional states of the patients. Results. The study revealed sympathetic predominance of the autonomic nervous system in patients with epilepsy associated brain tumors as opposed to parasympathetic predominance in non epilepsy associated brain tumors indicating significant stress to regulatory systems and depletion of subcortical reserves of the cardiovascular system, further more stretching the adaptation limits, ultimately leading to depression of autonomic regulatory mechanisms and predominance of central mechanisms of regulation and adaptation. Conclusion. Frequency-amplitude analysis of electroencephalogram and cardiointervalogram allow us to assess the degree of distress of different cortical and subcortical regulatory systems in patients with brain tumors, and is recommended as an additional method of investigation in these patients.

Endurance and fatigue caused by local muscular performance in skilled athletes

It was the objective of this research to study the functional parameters of endurance and performance and the brain electrobiological activity during local antebrachial muscle work performance among skilled athletes and unfit people aged 18-23. We examined performance and the brain bioelectrical activity changes at local muscle work by means of an ergograph until fatigue. Our results suggested that local performance increased the spectral power of slow alpha- and theta waves as the fatigue set in, but these changes developed slower and were manifested later in the athletes than in the unfit people. Besides, tired athletes' EEGs showed alpha waves synchronization and only demonstrated a decrease in low- and high frequency beta waves indexes. Athletes show higher performance and lower fatigability if compared to unfit people during local performance, also proved by the EEG bioelectrical changes.