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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 various signal distortions and to electrical activity signals in the brains of mice under normal conditions and after one day of sleep deprivation. We show that the latter states can be distinguished by several EDFA scaling exponents, but their performance is scale dependent. The maximum differences between the states quantified by conventional and extended fluctuation analysis may be associated with different scale ranges. We conclude that the statistical analysis of local fluctuations in the signal profile is useful for developing diagnostically significant markers of the system state. [ABSTRACT FROM AUTHOR]

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 absence of differences, and also to demonstrate how the distribution of local fluctuations of signal profiles from the trend makes it possible to obtain additional information about the complex organization of ECoG signals. Based on this information, the analysis of physiological experiments can be performed more thoroughly than using only one diagnostic marker, such as the DFA scaling exponent. The practical importance of such thorough signal processing is the possibility of better control of the depth of anesthesia in long-term physiological experiments, when sensitive diagnostic markers become high relevance. [ABSTRACT FROM AUTHOR]

An extension of detrended cross-correlation analysis (DCCA) for processing interrelated nonstationary time series is considered using electrocorticograms (ECoG) in mice as an example. The application of this approach to the case of wakefulness and 1-day sleep deprivation is discussed. It is shown that, although the DCCA method enables to detect changes in ECoG caused by sleep deprivation, its extension improves the separation of the dynamics and may reduce the amount of data required to identify the state of the brain electrical activity. [ABSTRACT FROM AUTHOR]

We explore the capabilities of multiresolution wavelet analysis (MWA) to characterize complex dynamics based on short data sets that can be applied for diagnosing inter-state transitions. Using the example of chaos–hyperchaos transitions in the model of two interacting Rössler systems, we establish the minimum amount of data necessary for reliable separation of chaotic and hyperchaotic oscillations and discuss how this amount changes depending on the length of the transient process. We then discuss transitions between wakefulness and artificial sleep in mice and estimate the duration of electroencephalograms (EEG) that provide separation between these states. [ABSTRACT FROM AUTHOR]

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 in peripheral tissues. The brain actively exchanges nutrients with the blood and excretes metabolic waste products through the drainage routes closely related to the peripheral lymphatic system. The same routes allow the traffic of immune cells and antibodies to the CNS, thus providing a communication between the peripheral and central immune systems. Over the bicentennial history of brain drainage studies, a lot of facts have been accumulated to suggest indirectly the presence of lymphatic vessels in the CNS. However, even with the advent of high-tech imaging of brain structures and a rediscovery of the meningeal lymphatic vessels (MLVs), which was a watershed in neuroscience, scientists have not advanced beyond confirming the already existing dogma that the lymphatic network is present exclusively in the brain meninges, but not in brain tissues. In fact, however, the rediscovery of MLVs by American scientists was not a "true revelation", as they were first described by the Italian anatomist Mascagni two centuries earlier, and his results were confirmed later on in many other studies performed on the meninges in humans, macaques, rodents, dogs, rabbits and zebrafish. As a result, the scientific community did not recognize the "forgotten" MLVs as a new discovery. This review highlights the turning points that occurred in neuroscience when a new player has entered the game and orchestrated innumerable efforts of scientists to explain how unnecessary molecules and toxins are removed from the brain, as well as how drainage and immunity are implemented in the CNS. This is an important informational and creative platform both for new fundamental knowledge about the lymphatic system in the brain, as well as for the development of innovative neurorehabilitation technologies based on the management of lymphatic drainage processes. [ABSTRACT FROM AUTHOR]

We study changes in the blood–brain barrier (BBB) permeability in mice caused by a 2-h intermittent sound and discuss their reflection in the electrical activity of the brain. Using the detrended fluctuation analysis (DFA), multiresolution wavelet analysis (MWA) and their recent modifications, we compare the capabilities of reliably characterizing the transitions between closed and open BBB states. It is shown that an enhanced approach, combining MWA with DFA of the decomposition coefficients, improves the interstate separation by limiting the most appropriate level of resolution. This approach can be useful in various studies of complex systems based on experimental data. [ABSTRACT FROM AUTHOR]

Extended detrended fluctuation analysis (EDFA) is a recently proposed modification of the conventional method, which provides a characterization of complex time series with varying nonstationarity. It evaluates two scaling exponents for a better quantification of inhomogeneous datasets. Here, we study the effect of different types of nonstationarity on these exponents, including trend, switching between processes with distinct statistical properties and energy variability. Using the simulated signals, we show that the first two types of nonstationarity have the strongest effect for anticorrelated processes and complicate their diagnosis. Nonstationarity in energy is more crucial for time series with positive long-range correlations. Next, we apply EDFA to rat experiments to study the activation of brain lymphatic drainage during sleep. Our analysis reveals significant distinctions in EDFA’s measures between the background electrical activity of the brain and the stage of sleep. The latter offers an indirect way to identify and characterize the nightly activation of the drainage and clearance of brain tissue. [ABSTRACT FROM AUTHOR]

The effect of photoinduced enhancement of Evans blue (EB) dye fluorescence in blood plasma and albumin solution has been considered. Manifestations of the dye fluorescence enhancement in the albumin solution and rat blood plasma have been compared. Saturation of photoinduced fluorescence, the effect of enhanced fluorescence delay, and divergence in fluorescence spectra of the solutions have been found for the first time. Based on the obtained results, a hypothesis about the presence of nonfluorescent complexes with the EB participation in blood plasma is proposed. [ABSTRACT FROM AUTHOR]

The autofluorescence spectroscopy of biological tissues is a powerful tool for non-invasive detection of tissue pathologies and evaluation of any biochemical and morphological changes arising during the lesions' growth. To obtain a full picture of the whole set of endogenous fluorophores appearing in the gastrointestinal (GI) tumors investigated, the technique of excitation-emission matrix (EEM) development was applied in a broad spectral region, covering the ultraviolet and visible spectral ranges. We could thus address a set of diagnostically-important chromophores and their alterations during tumor development, namely, collagen, elastin, nicotinamide adenine dinucleotide (NADH), flavins, porphyrins, while hemoglobin's absorption influence on the spectra obtained could be evaluated as well. Comparisons are presented between EEM data of normal mucosae, benign polyps and malignant carcinoma, and the origins are determined of the fluorescence signals forming these matrices. [ABSTRACT FROM AUTHOR]

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. Synchronous fluorescence spectroscopy (SFS) allows improving the spectral resolution, which could be useful for the biological tissue fluorescence characterization and could increase the tumour detection diagnostic accuracy. [ABSTRACT FROM AUTHOR]

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 illustrated. [ABSTRACT FROM AUTHOR]

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 prostacyclin synthesis. The removal of the testicles abolished the pressor influence of glybenclamide in hypertensive and, particularly, in normotensive males. These data indicate that the non-endothelial vascular effects of androgens ( i.e., stimulation of KATP channels) predominate under normal conditions. The activating effects of androgens on KATP channels decrease during hypertension, which is accompanied by inhibition of endothelium-dependent vasorelaxation. The production of nitric oxide and prostacyclin remains unchanged under these conditions. Our results suggest that endothelium-derived hyperpolarizing factor is involved in these processes. [ABSTRACT FROM AUTHOR]

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 pronounced than the vascular response females demonstrated greater cardiac response and less signifi cant vascular reactions than males. Aging was accompanied by a decrease in the cardiac response and increase in the vascular reaction to stress. These changes were more significant in females than in males. In contrast to infantile and adult animals, old females demonstrated greater vascular response to stress than male rats. The observed sex-dependent changes in the ontogeny of vascular and cardiac response to stress are discussed in light of sex- and age-related peculiarities of hypertension development. [ABSTRACT FROM AUTHOR]

The mean blood pressure did not depend on the sex of animals and was characterized by the same ontogenetic changes in males and females. The mean blood pressure in infantile and, particularly, in old rats was higher than in adult animals. The increase in blood pressure in old rats was accompanied by a decrease in NO production. Infantile rats were least resistant to the development of renal hypertension. The degree of hypertension in infantile and adult females was lower than in males. However, the concentration of NO in these females was higher than in male rats. Aging was accompanied by inversion of sex differences in the resistance to renal hypertension. The severity of hypertension in old females was greater than in males. It was accompanied by a signifi cant age-related decrease in NO concentration in female animals. Our results indicate that NO plays an important role in sex differences in the resistance of infantile, adult, and old rats to hypertension, while the decrease in NO concentration during aging leads to blood pressure elevation in females and males. [ABSTRACT FROM AUTHOR]

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 in the functional state of the organism. In this paper, we discuss the age aspect in the cooperative dynamics of EEG rhythms. We report significant differences in pairwise rhythm interactions for groups of subjects of different ages and show that, regardless of the type of correlations between individual brain waves, they increase with age, which is manifested in the state of wakefulness. The corresponding differences are less pronounced during deep sleep. [ABSTRACT FROM AUTHOR]