Oxana Glushkovskaya

• Saratov State University

A promising topic in the study of brain rhythms is their consideration within the framework of the phenomenon of network interactions, when attention is focused not on individual EEG waves, i.e. the electrical activity of the brain in the particular frequency bands, but on their continuous coordination and varying cross-communications with changes...

Unlabelled: The aim was to study the relationship between net water uptake (NWU) and cerebral oxygenation in patients with posttraumatic ischaemia (PTI) foci after moderate traumatic brain injury (moTBI). Materials and methods: Perfusion computed tomography (PCT) was performed for 72 patients with PTI foci after moTBI in 2013-2022. The mean age...

Using rat electrocorticograms (ECoG), we discuss how detrended fluctuation analysis (DFA) and its recently proposed extension characterize anesthesia effects in the electrical activity of the brain. Two groups of animals with injection and inhalation anesthesia are considered to reveal differences in ECoG depending on the type of anesthetic or the...

Local fluctuations in the profile can vary significantly for nonstationarity signals produced, e.g., by physiological systems. To correctly identify distinctions between the states of such systems, these fluctuations should be processed thoroughly. In the current study, we apply extended detrended fluctuation analysis (EDFA) to simulated data with...

Long-range correlations are often used as diagnostic markers in physiological research. Due to the limitations of conventional techniques, their characterizations are typically carried out with alternative approaches, such as the detrended fluctuation analysis (DFA). In our previous works, we found EEG-related markers of the blood–brain barrier (BB...

The lymphatic system not only plays an important role as a drainage eliminating metabolic wastes and toxins from tissues, but also represents an arena for the unfolding of immune response scenarios aimed at protecting the organism from bacteria and viruses. In the central nervous system (CNS), drainage processes proceed with the same intensity as i...

A coarse-graining procedure, which involves averaging time series in non-overlapping windows followed by processing of the obtained multiple data sets, is the initial step in the multiscale entropy computation method. In this paper, we discuss how this procedure can be applied with other methods of time series analysis. Based on extended detrended...

Photodynamic therapy is a highly perspective tool for cancer treatment. The PDT method has been used for more than 30 years to treat patients with brain cancer. In recent years, the active study of reactive oxygen species and, in particular, the properties of singlet oxygen have opened up new prospects for the use of PDT, and also opened the veil o...

We report here a pilot identification of the presence of the lumenized Lyve-1/Prox-1-expressing vessels with distinct walls composed of a single endothelial layer in the unaffected brain and with intraventricular hemorrhages. These lymphatic vessels (LVs) have valves and an undulating shape in the distal region that is the classical characteristic...

The quantification of transport processes of different substances in the brain’s parenchyma is important in the context of understanding brain functioning. Most of the currently used methods for assessment of the effective diffusion coefficient rely on the point-source paradigm. We propose a method for the quantitative characterization of the diffu...

Sleep plays a crucial role in maintaining brain health. Insufficient sleep leads to an enhanced permeability of the blood–brain barrier and the development of diseases of small cerebral vessels. In this study, we discuss the possibility of detecting changes in the electrical activity of the brain associated with sleep deficit, using an extended det...

Music plays a more important role in our life than just being an entertainment. For example, it can be used as an anti-anxiety therapy of human and animals. However, the unsafe listening of loud music triggers hearing loss in millions of young people and professional musicians (rock, jazz and symphony orchestra) owing to exposure to damaging sound...

Music plays a more important role in our life than just being an entertainment. It is an even anti-anxiety therapy of human and animals. However, the unsafe listening of loud music triggers hearing loss in millions of young people and professional musicians (rock, jazz, and symphony orchestra) due to exposure to damaging levels of sound using perso...

The quantification of transport processes of different substances in the brain’s parenchyma is important in the context of understanding brain functioning. Most of the currently used methods for assessment of the effective diffusion coefficient rely on the point-source paradigm. We propose a method for the quantitative characterization of the diffu...

Photodynamic therapy (PDT) is a promising tool for least-invasive alternative methods for the treatment of brain tumors. The newly discovered PDT-induced opening of the blood–brain barrier (BBB) permeability open novel strategies for drug-brain delivery during post-surgical treatment of glioblastoma GBM. Here we discuss mechanisms of PDT-mediated o...

This seems to be the time to gain new knowledge about the meningeal lymphatic system and a deeper understanding of its anatomy and physiology. Although it is known that the meningeal lymphatics present in the layers of the brain, limited information is available about the role of this system in brain function. Here, for the first time we clearly de...

Cerebrovascular reactivity (CVR) is a compensatory mechanism where blood vessels dilate in response to a vasodilatory stimulus, and is a biomarker of vascular reserve and microvascular health. Impaired CVR indicates microvascular hemodynamic dysfunction, which is implicated in traumatic brain injury (TBI) and associated with long-term neurological...

In this paper, measurements of the optical properties (diffuse reflectance, total and collimated transmittance) of brain tissues in healthy rats and rats with C6-glioma were performed in the spectral range from 350 to 1800 nm. Using these measurements, characteristic tissue optical parameters, such as absorption coefficient, scattering coefficient,...

The peripheral lymphatic system plays a crucial role in the recovery mechanisms after many pathological changes, such as infection, trauma, vascular, or metabolic diseases. The lymphatic clearance of different tissues from waste products, viruses, bacteria and toxic proteins significantly contributes to the correspondent recovery processes. However...

Fluorescent microscopy of the brain clearing from the FITC‐dextran (red color) via the meningeal lymphatic vessels (green color, labelled by specific antibodies LYVE‐1 conjugated with Alexa 488). The FITC‐dextran injected intravenously immediately is observed in the Sagittal sinus (the main cerebral vein) and after photodynamic opening of blood‐bra...

Malignant gliomas are highly invasive tumors that use the cerebral vessels for invasion due to high vascular fragility of the blood–brain barrier (BBB). On one hand, glioma is characterized by the BBB disruption, on the other hand, drug brain delivery via the BBB is a big challenge in glioma therapy. The limited information about vascular changes a...

The effects of light‐driven enhancement of Evans Blue dye complexes with blood plasma proteins were observed for the first time, both in vitro and in vivo. The possible background of the effect concerns the photochemical cis‐trans isomerization of the azo dye molecules. The effect was induced in the solution with a red laser with a wavelength of 63...

A new application of the photodynamic treatment (PDT) is presented for the opening of blood-brain barrier (BBB) and the brain clearing activation that is associated with it, including the use of gold nanoparticles as emerging photosensitizer carriers in PDT. The obtained results clearly demonstrate two pathways for the brain clearing: 1) using PDT-...

The scaling properties of complex processes may be highly influenced by the presence of various artifacts in experimental recordings. Their removal produces changes in the singularity spectra and the Hölder exponents as compared with the original artifacts-free data, and these changes are significantly different for positively correlated and anti-c...

The meningeal lymphatic vessels were discovered 2 years ago as the drainage system involved in the mechanisms underlying the clearance of waste products from the brain. The blood-brain barrier (BBB) is a gatekeeper that strongly controls the movement of different molecules from the blood into the brain. We know the scenarios during the opening of t...

Photodynamic treatment (PDT) causes a significant increase in the permeability of the blood-brain barrier (BBB) in healthy mice. Using different doses of laser radiation (635 nm, 10-40 J/cm²) and photosensitizer (5-aminolevulinic acid – 5-ALA, 20 and 80 mg/kg, i.v.), we found that the optimal PDT for the reversible opening of the BBB is 15 J/cm² an...

Here, we discuss an important problem in medicine as development of effective strategies for brain drug delivery. This problem is related to the blood–brain barrier (BBB), which is a “customs” controlling the entrance of different molecules from blood into the brain protecting the normal function of central nervous system (CNS). We show three inter...

Based on the laser speckle contrast imaging (LSCI) and the multiscale entropy (MSE), we study in this work the blood flow dynamics at the levels of cerebral veins and the surrounding network of microcerebral vessels. We discuss how the phenylephrine-related acute peripheral hypertension is reflected in the cerebral circulation and show that the obs...

Laser speckle contrast imaging (LSCI) has become one of the most common tools for functional imaging in tissues. Incomplete theoretical description and sophisticated interpretation of measurement results are completely sidelined by a low-cost and simple hardware, fastness, consistent results, and repeatability. In addition to the relatively low mea...

Here we show the photodynamics (PD)-induced opening of the blood-brain barrier in dependence on different light doses and concentrations of photosensitizer that is important for correction of PD-related fluorescence guided resection of brain tumor.

We consider here an approach for multifractal analysis of cerebrovascular dynamics that provides a relation between the occurred changes in the blood flow velocity and the physiological mechanisms of cerebral regulation. We apply this approach to study responses of the cerebral dynamics in rats to variations in the peripheral blood pressure and sho...

In our study we investigate the characteristic differences, with diagnostic meaning, in the synchronous fluorescence spectra (SFS) of cancerous and healthy colorectal tissues, ex vivo. The main observed fluorophores which fluorescence has a diagnostic meaning are tyrosine, tryptophan, NADH, FAD, collagen, elastin, and porphyrines. In the SFS of thr...

Using the method of laser speckle imaging for the simultaneous study of macro- and microcirculation in cerebral vessels of healthy rats, we show that the mechanisms underlying cerebral autoregulation depend on the initial condition of the organism and the sex of individual animals. The pharmacological dose-dependent stimulation of the peripheral ar...

In this study, we analyzed the time-depended scenario of stress response cascade preceding and accompanying brain hemorrhages in newborn rats using an interdisciplinary approach based on: a morphological analysis of brain tissues, coherent-domain optical technologies for visualization of the cerebral blood flow, monitoring of the cerebral oxygenati...

In this review, we describe the phenomenon of intra-cranial hemorrhage (ICH), which occurs spontaneously within the first 2-3 days of life in full-term newborns without any clinical symptoms, but with long-term neurological outcomes in many cases. We give the estimated frequency and possible mechanisms responsible for silent ICH with main focus on...

Neonatal hemorrhagic stroke (NHS) is a major problem of future generation’s health due to the high rate of death and cognitive disability of newborns after NHS. The incidence of NHS in neonates cannot be predicted by standard diagnostic methods. Therefore, the identification of prognostic markers of NHS is crucial. There is evidence that stress-rel...

Application of noninvasive optical coherent-domain methods and advanced data processing tools such as the wavelet-based multifractal formalism allows revealing effective markers of early stages of functional distortions in the dynamics of cerebral vessels. Based on experiments performed in rats we discuss a possibility to diagnose a hidden stage of...

Here we studied the role of nitric oxide in cardiovascular regulation in male and female hypertensive rats under normal and stress conditions. We found that the severity of hypertension in females was lower than in males. Hypertensive females demonstrated more favorable pattern of cardiovascular responses to stress. Nitric oxide blockade by NG-nitr...

It was shown in the experience with 60 white mice that separate and combined effects of stress factors: noctidial lighting (800 lux), sodium nitrite (0.2% solution in water) and p-toluidine (with food) within 107 days causes a change in impedance value of erythrocytes at frequencies 1 Hz – 1MHz. Changes in the activity of intracellular aminotransfe...

In this paper we address the problem of revealing and recognition transitions between distinct physiological states using quite short fragments of experimental recordings. With the wavelet-based multifractal analysis we characterize changes of complexity and correlation properties in the stress-induced dynamics of arterial blood pressure in rats. W...

The human skin is a complex, multilayered and inhomogeneous organ with spatially varying optical properties. Analysis of cutaneous fluorescence spectra could be a very complicated task; therefore researchers apply complex mathematical tools for data evaluation, or try to find some specific approaches, that would simplify the spectral analysis. Sync...

Sex differences in stress-related diseases such as stroke and stomach cancer are well established, but the mechanisms underlying this phenomenon remain unknown. Despite the fact that sexual hormones play an important role in the high resistance of females to harmful effects of stress compared with males, the regulation of oxygenation status can be...

We studied the level of blood oxygen saturation (SpO2) in the brain in newborn rats in the pre- and post-stroke periods, as well as the changes in cerebral blood flow and beta-arrestin-1 as a marker of hypoxic stress. Our results show that mild hypoxia precedes the stroke development and is associated with venous relaxation and decrease blood outfl...

Here we describes a new model of stress-induced cerebral hemorrhage in newborn rats. Using histological and laser speckle imaging, we characterized changes in the brain tissues and circulation associated with the pre- and post-hemorrhage periods.

Chronic hypertension itself does not cause stroke but significantly decreases the resistant to stroke induced by stress due to exhausting of adaptive capacity of cerebral endothelium and decrease resistance of blood-brain barrier to stress.

Neonatal stroke is similar to the stroke that occurs in adults and produces a significant morbidity and long-term neurologic and cognitive deficits. There are important differences in the factors, clinical events and outcomes associated with the stroke in infants and adults. However, mechanisms underlying age differences in the stroke development r...

Stress is a major factor for a risk of cerebrovascular catastrophes. Studying of mechanisms underlying stress-related brain-injures in neonates is crucial for development of strategy to prevent of neonatal stroke. Here, using a model of sound-stress-induced intracranial hemorrhages in newborn rats and optical methods, we found that cerebral veins a...

Using the wavelet-transform modulus maxima (WTMM) approach we study the dynamics of cerebral blood flow (CBF) in rats aiming to reveal responses of macro- and microcerebral circulations to changes in the peripheral blood pressure. We show that the wavelet-based multifractal formalism allows quantifying essentially different reactions in the CBF-dyn...

In this paper we study the cerebrovascular dynamics in newborn rats using the wavelet-based multifractal formalism in order to reveal effective markers of early pathological changes in the macro- and microcirculation at the hidden stage of the development of intracranial hemorrhage (ICH). We demonstrate that the singularity spectrum estimated with...

Laser speckle contrast imaging (LSCI) is a powerful tool for blood flow mapping. In this paper, we described a simple algorithm based on histogram analysis of laser speckle contrast image to provide rapid differentiation between macro- and microcirculations. The algorithm was successfully verified by the study of blood flow in rat cortex under func...

Using the laser speckle contrast imaging and wavelet-based analyses, we investigate a latent (a "hidden") stage of the development of intracranial hemorrhages (ICHs) in newborn rats. We apply two measures based on the continuous wavelet-transform of blood flow velocity in the sagittal sinus, namely, the spectral energy in distinct frequency ranges...

Excitation-emission matrices were used for detection of the autofluorescence properties of surgically excised normal and cancerous mucosa of lower gastrointestinal tract tissues (colon and rectum carcinoma). Linear polarization of the excitation and emission fluorescence light was additionally applied to evaluate the influence of anisotropic fluoro...

The incidence of perinatal hemorrhagic stroke (HS) is very similar to that in the elderly and produces a significant morbidity and long-term neurologic and cognitive deficits. There is strong evidence that cerebral blood flow (CBF) abnormalities make considerable contribution to HS development. However, the mechanisms responsible for pathological c...

We investigate the stress-induced development of the intracranial hemorrhage in newborn mice with the main attention to its latent stage. Our study is based on the laser speckle contrast imaging of the cerebral venous blood flow and the wavelet-based analysis of experimental data. We study responses of the sagittal sinus in different frequency rang...

In this report we will present our recent investigations of the fluorescence properties of lower part gastrointestinal tissues using excitation-emission matrix and synchronous fluorescence spectroscopy measurement modalities. The spectral peculiarities observed will be discussed and the endogenous sources of the fluorescence signal will be addresse...

Synchronous autofluorescence spectroscopy (SFS) using excitation in the range of 280-440 nm and varying delta lambda from 10 to 200 nm were applied on lower GIT tumours obtained after surgical excision. Due to the improved efficiency of SFS for the signals, where the delta lambda is optimal, we could obtain higher spectral resolution for the detect...

Neonatal brain hemorrhages is a major problem of future generation’s health due to the high rate of cognitive disability of newborns after vascular catastrophes in the brain. Despite the public health impact of neonatal brain hemorrhages, the mechanisms underlying in these pathological processes remain unknown. Here, using a model of sound-stress-i...

Intracranial hemorrhage (ICH) is the major problem of modern neonatal intensive care. Abnormalities of cerebral venous blood flow (CVBF) can play a crucial role in the development of ICH in infants. The mechanisms underlying these pathological processes remain unclear; however it has been established that the activation of the adrenorelated vasorel...

The adrenergic system plays an important role in regulation of central and peripheral circulation in normal state and during hemorrhage. Because the impaired gastric mucosal blood flow (GMBF) is the major cause of gastroduodenal lesions, including ulcer bleeding (UB), we studied the adrenergic mechanism responsible for regulation of GMBF in rats wi...

We present fluorescence data obtained from normal and cancerous gastrointestinal tissues - oesophageal and colon lesions, taken up to two hours after surgical removal with and without exogenous fluorescent markers applied. The major goal was to acquire information on the differences between the fluorescent spectra of normal and pathological tissues...

Using Doppler optical coherence tomography (DOCT) we study stress-related intracranial hemorrhages (ICHs) in newborn rats. We investigate a masked stage of ICH development that corresponds to the first 4 h after the stress. We show that this period is characterized by significant changes in the diameter of the sagittal vein and the velocity of the...

In this paper, we discuss a relationship between stress-induced formation of hypertension and ulcer bleeding and the level of serum testosterone in female and male rats. We show that the secretion of testosterone is an important sign of severity of stress-induced damages of vascular homeostasis in males but not in females.

We study pathological changes in cerebral venous dynamics in newborn mice using the laser speckle contrast imaging and the detrended fluctuation analysis with a special attention to the latent stage of the development of the intracranial hemorrhage. We show that this stage is characterized by a high responsiveness of the sagittal sinus to pharmacol...

The study of blood microcirculation is one of the most important problems of the medicine. This paper presents results of experimental study of cerebral blood flow microcirculation in mice with alloxan-induced diabetes using Temporal Laser Speckle Imaging (TLSI). Additionally, a direct effect of glucose water solution (concentration 20% and 45%) on...

Intracranial hemorrhage (IH) is a major problem of neonatal intensive care. The incidence of IH is typically asymptomatic and cannot be effectively detected by standard diagnostic methods. The mechanisms underlying IH are unknown but there is evidence that stress-induced disorders in adrenergic regulation of cerebral venous blood flow (CVBF) are am...

The burning issue in modern medicine is the diagnosis and treatment of various life-threatening diseases, in particular the diseases of brain. One of them is intracranial hemorrhage (ICH). It occurs especially among newborn babies and is hard-diagnosed. In order to understand the nature of the ICH, the microcirculation of blood, which serves key fu...

Nitric oxide (NO) plays an important role in regulation of central and peripheral circulation in normal state and during hemorrhagic stress. Because the impaired gastric mucosal blood flow is the major cause of gastroduodenal lesions including ulcer bleeding (UB), we study in this work the NO-ergic mechanism responsible for regulation of this blood...

A method of adaptive wavelet analysis permitting one to set parameters of the wavelet transform based on principles of the optimization theory is proposed. Applying the method to optical coherent tomography data processing is considered. The efficiency of the proposed method for diagnosing functional disorders in the dynamics of cerebral vessels is...

In experiments on newborn rats with stress-related intracranial hemorrhage (ICH) using Doppler optical coherence tomography (DOCT) we have shown that latent stage of ICH (4 h after stress) is characterized by decrease of venous blood outflow and the loss of sensitivity of sagittal vein to vasoconstrictor effect of adrenaline. The incidence of ICH (...

Hemorrhagic insult is a major source of morbidity and mortality in both adults and newborn babies in the developed countries. The mechanisms underlying the non-traumatic rupture of cerebral vessels are not fully clear, but there is strong evidence that stress, which is associated with an increase in arterial blood pressure, plays a crucial role in...

Wavelets are widely used to improve the quality of images by digital filtering of noise. In this work, application of wavelet-filtering to OCT-images is considered. The problem of appropriate selection of the wavelet-basis is discussed and analysis of cerebral arteries in newborn rats is performed.

The results of experimental approbation of the method of laser full-field speckle-imaging for monitoring the changes in blood microcirculation state of the brain cortex of laboratory rats under the conditions of developing stroke and administration of vasodilating and vasoconstrictive agents are presented. The studies aimed at the choice of the opt...

Castration had no effect on baseline BP and vascular sensitivity to acetylcholine and deficiency of nitric oxide and prostacyclin in normotensive specimens. Castration of hypertensive specimens decreased BP and potentiated the hypotensive effects of acetylcholine, but did not modulate vascular sensitivity to the blockade of nitric oxide and prostac...

Stress exposure induced similar cardiac effects in male and female infantile rats, but vascular reactions to stress in males were more pronounced than in females. In mature male rats (but not in females), both cardiac and vascular responses to stress decreased in comparison with infantile animals. In adult rats, cardiac effects of stress were more...

This paper presents the results of experimental study of full field laser speckle imaging due to cortex microcirculation state monitoring for laboratory rats under conditions of stroke and the introduction of agents. Three groups of experimental animals from five animals in each group were studied. The behavior of blood flow, studied by speckle ima...

Studying of nitric oxide (NO) dependent mechanisms of regulation of microcirculation in a stomach can provide important diagnostic markers of the development of stress-induced ulcer bleedings. In this work we use a multiscale analysis based on the discrete wavelet-transform to characterize a latent stage of illness formation in rats. A higher sensi...