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It is shown that for reliable operation of laser diode matrices, it is important to ensure the maximum allowable, but not leading to their destruction, current input and output rate. Some of the solutions used in the design of laser diode drivers are listed in order to limit the increase in the rate of current input and output. A method for controlling the rate of rise of the laser emitter current is proposed, the essence of which is to form the leading and trailing edges of the output current of the laser driver so that its first and, at least, the second derivative are continuous, in order to avoid triggering internal mechanisms that lead to degradation of the emitter structure.

—The kinetics of fluorescence decay of the K-35 probe and the tryptophan amino acid residue were measured after the addition of sodium hypochlorite in human albumin serum (HSA). The K-35 fluorescent probe (excitation 405 nm, fluorescence 530 nm) binds to drug binding site I of albumin. During the experiment the molar concentration of albumin in the fraction varied from 0.3 to 20 μM. Oxidation of the fraction with hypochlorite was recorded by the change in the fluorescence of tryptophan also located in binding site I of albumin (excitation 290 nm, fluorescence 350 nm). It was shown that, at serum albumin concentration of about 30 μM, HSA has antioxidant activity which maintains its ability to bind ligands even after exposure to relatively large amounts of hypochlorite (up to 50 oxidizing molecules per protein molecule). HSA retains its ability to bind ligands because the properties of the K-35 probe during oxidation remained almost unchanged and we observed only insignificant changes in binding characteristics. The added hypochlorite is, predominantly, used to oxidize albumin amino acids, including Trp oxidation as observed in the experiment. For 14 sera of donors, we showed significant differences in the fluorescence of oxidized and native tryptophan.

Relevance. Pentanedioic acid imidazolyl ethanamide (PAIE) has been used clinically as an antiviral agent for a long time, however, there is no information in the available literature concerning the dependence of PAIE pharmacokinetics on isoenzymes polymorphism of the cytochrome P450 system (CYP), as well as on the variability of pharmacokinetic parameters in humans. The aim of the study is to determine the main pharmacokinetic parameters of PAIE in healthy volunteers and to assess the contribution of polymorphism of CYP P450 isoenzymes to the variability of pharmacokinetic parameters.Material and methods. The study included 12 healthy volunteers (5 men and 7 women) of the Caucasian race, who took In[1]gavirin® at a dose of 180 mg (2 capsules of 90 mg) on an empty stomach during two dosing periods, separated by a 7-day washout period. Determination of PAIE concentration in blood plasma and urine samples was carried out by high-performance liquid chromatography–mass spectrometry. Polymorphism of CYP genes was analyzed using the polymerase chain re[1]action method in order to analyze the pharmacogenetic features of PAIE metabolism in volunteers during the study.Results. After oral administration, PAIE quickly reached the systemic circulation: the maximum concentration of 578.88±145.21 ng/ml was observed after about 2 hours. Pharmacokinetic parameters of PAIE did not show high intraindividual variability and did not depend on polymorphism of isoenzymes CYP1A1, CYP2C9, and CYP2D6. Within 48 hours after the administration of the studied drug, about half of the taken dose of PAIE was excreted in the urine unchanged, which indicates a significant contribution of the kidneys to the elimination of PAIE. The only adverse event registered in 1 volunteer was a clinically insignificant decrease in the level of leukocytes, which did not require medical intervention and was resolved without consequences.Conclusion. PAIE is characterized by predictable pharmacokinetics, low intraindividual variability of pharmacokinetic parameters, and a favorable safety profile.

We describe an experiment on the interaction of a dipolar magnetic field with the laser plasma flow produced inside of a laboratory magnetosphere. This interaction is found to exhibit two dynamic stages: after a prompt displacement of the dipole field by the laser plasma, the magnetic field is captured and carried outside of the magnetosphere. The resultant data confirm the results of previous measurements carried out far beyond the magnetosphere and provide additional information about the new process of capturing the dipolar magnetic field by the internal magnetospheric plasma flow.

Successful colonization of the intestine requires that bacteria interact with the innate immune system and, in particular, neutrophils. Progression of inflammatory bowel diseases (IBD) is associated with alterations in gut microbiota, and dysbiosis in Crohn’s disease (CD) patients is often associated with an expansion of Escherichia coli. Here, we investigated the ability of such E. coli isolates to avoid neutrophil activation and to utilize reactive oxygen species. Neutrophil activation was detected in vitro in normal human blood via luminol chemiluminescence (CL) induced by reactive oxygen and halogen species generated by neutrophils. No significant difference in neutrophil activation in vitro was detected between isolates from inflamed (23 isolates) vs healthy intestines (5 isolates), with 10‐fold variation within both groups (2.9–61.2 mV). CL activity of isolates from the same patient differed by 1.5–5 times. Twenty‐four isolates from ileal aspirate, biopsy, and feces of seven patients with CD and one patient with no intestine inflammation were tested for extracellular peroxidase and catalase activity and cell surface hydrophobicity. Average values between patients varied from 26 ± 3 to 73 ± 18 µmol·g−1 of air dry weight for peroxidase activity, from 15 ± 2 to 189 ± 56 mmol·g−1 of air dry weight for catalase activity, and from 5 ± 3 to 105 ± 9 a.u. for the hydrophobic probe fluorescence. Extracellular peroxidase activity and hydrophobicity of bacterial cell surface correlated negatively with stimulated neutrophil CL. The ability of some isolates to avoid neutrophil activation and to utilize reactive oxygen species may provide a strategy to survive assault by the innate immune system., The ability of Escherichia coli isolates from the intestines of Crohn’s disease (CD) patients to avoid neutrophil activation and to utilize reactive oxygen species was analyzed. Neutrophil activation was detected in vitro in normal human blood via luminol chemiluminescence (CL). Extracellular peroxidase activity and hydrophobicity of bacterial cell surface correlated negatively with stimulated neutrophil CL.

The problem of signal transmission in experimental installations is of particular importance for plasma physics due to the characteristic powerful impulse noise caused by the operation of power equipment. This article describes a filter based on a broadband in-phase transformer designed to transmit signals at the KI-1 solar plasma simulation facility of the Institute of Laser Physics, SB, RAS. The parameters of the plasma produced by exposure to a pulse of powerful CO2-laser to a solid-state target, sharply differ from the plasma parameters of confinement installations, which makes the known methods of signal transmission based on classical transformers and optocouplers unacceptable. The presence of X-rays also imposes restrictions on the use of fiber optic solutions.

The antioxidant and antiradical properties of the tetra nitrosyl iron complex with thiosulfate ligands (TNIC) in the mouse brain homogenates in vitro were also studied. It was found for the first time that TNIC is an effective antioxidant. The effect of TNIC on the catalytic activity of mitochondrial enzymes: cytochrome c oxidase and monoamine oxidase A has been studied. It was shown for the first time that TNIC is an inhibitor of the catalytic activity of cytochrome c oxidase and monoamine oxidase A in the brain mitochondria isolated from animals in vitro.

—The goal of this work was to search for blood serum parameters that would be associated with the state of patients with mental disorders. Such indicators are needed for an objective assessment of this state versus the prevailing subjective evaluation methodologies. The kinetics of tryptophan fluorescence decay in the serum albumin fraction was compared in patients with melancholic depression (before treatment) and in healthy volunteers. Albumin fluorescence is mainly due to the tryptophan 214 residue, which is located in the immediate vicinity of the first drug-binding center of the molecule. The decay kinetics were described as a sum of three exponential functions with lifetimes τi (in the 6.5, 2.8 and 1.0 ns region) and the amplitudes Ai. The τi values were similar in both groups of individuals. In contrast, there was a significant difference between patients and controls in the A1/A3 amplitude ratio. It is suggested that the A1/A3 value can be considered as a potential marker indicating the presence or absence of melancholic depression in patients before treatment.

Nitric oxide (NO) mediates diverse physiological processes in living organisms. Small molecular NO donors usually lack stability and have a short half‐life in human tissues, limiting the therapeutic application. The anionic tetranitrosyl iron complex with thiosulfate ligands (TNIC) is one of the most promising NO donors. This study shows that bovine serum albumin (BSA) can effectively stabilize the TNIC complex under aerobic (physiological) conditions, which contributes to its prolonged action as NO donor. Our results demonstrated that TNIC-BSA inhibits formation of TBARS – standard biomarker for the lipid peroxidation induced oxidative stress. Also, it was found that TNIC-BSA inhibits the catalytic activity of mitochondrial membrane-bound enzymes: cytochrome c oxidase and monoamine oxidase A. Together, these results demonstrate that, stabilization of TNIC with BSA opens up the possibility of its practical application in chemotherapy of socially significant diseases.

The urgent introduction of distance education into the learning process due to the COVID-19 pandemic has become a spontaneous experiment, requiring urgent decisions, effective mechanisms to implement into the educational process and analysis of ongoing educational process. The possibilities of modern digital technologies made it possible to quickly set up the information component of education and to controle student’s knowledge. A detailed analysis of the communication between the faculty members of the department among themselves and analysis of the features of teaching and self-education of students in the field of medical radiology and oncology based on answers and comments with using Google classroom, Socrative, Messenger Telegram, etc. was made. Issues of communicative interaction between faculty members and students, psychological aspects of distance communication, language of instruction, logistics of distance education and methodological problems are described in details. It has been suggested that distance education may be equally effective for theoretical subjects in full-time study form, but when studying clinical disciplines, the priority should be given to traditional methods of teaching, involving student's bedside training. Taking into account technical possibilities and high risk of development of extreme and emergency situations, it is suggested to introduce permanent readiness for distance education, to create all – Ukrainian distance imitation service of patients’ follow-up. The importance of using the state language in training as the basis for mastering the professional Ukrainian and English language as the basis for mastering international medical experience is indicated.

The effect of fullerene-containing amphiphilic (co)polymers of N-vinylpyrrolidone (C60/PVP) differed in composition and topology of the polymer chains on the membrane structure of phosphatidylcholine liposomes was studied. Using the method of fluorescent probes it was found that the C60/PVP structures under study are localized in the phosphatidylcholine membrane in the region of glycerol fragments and fatty acid chains of phospholipids. The C60/PVP copolymers form complexes with 2,7-dibromoproflavin and pyrene probes. The effective equilibrium constants of the probe–C60/PVP complexes in aqueous solutions and in the liposome membrane were determined. It is most likely that the fullerene-containing (co)polymers of N-vinylpyrrolidone form complexes not only with fluorescent probes but also with phospholipids of the liposome membrane, which reduces the stability of the probe–C60/PVP complex.

Regularities of interaction of water-soluble pentaamino acid derivatives of fullerenes (WPDFs) with the lipid bilayer of phosphatidylcholine liposomes were studied using the fluorescent probe method. The studied WPDFs act as quenchers of fluorescence of the hydrophilic probe 2,7-dibromoproflavine in aqueous solutions and in the membranes of phsophatidylcholine liposomes, as well as of the hydrophobic probe pyrene in the phospholipid membrane. The singlet state of the probes is deactivated due to the formation of the long-lived WPDF—probe complex rather than their dynamic interaction. The WPDFs stud- ied were revealed to penetrate into the bilayer membrane of phosphatidylcholine liposomes. The localization of the pentaamino acid fullerene derivatives in the region of polar heads and fatty acid chains of the membrane phospholipids was established on the basis of estimation of the equilibrium constants in the WPDF—probe complexes.

In this paper, the state of the body’s antioxidant defense was studied using the state of thiol groups in the albumin in patients with their first episode of schizophrenia (FES). We examined 21 patients with the first psychotic attack of schizophrenia; the average severity of the disorders was 75 ± 2 points on the PANSS scale. All patients were examined prior to initiation of the drug therapy. The control group consisted of ten healthy volunteers. The concentration and reactivity of the albumin SH groups was determined in the reaction with dithionitrobenzoic acid. As a result of the study, we found a 24% decrease in the average reactivity of albumin SH groups in the FES group compared with the control group (p = 0.02). Using two parameters, that is, the concentration and reactivity of albumin thiols, it was possible to separate the patient group and the control group, with the probability of a relationship of the patient to the respective group of 86%. Thus, patients with the first episode of schizophrenia before the start of treatment are characterized by significant disturbances in the concentration and reactivity of the albumin SH-groups involved in redox processes in the body.

A high-speed current transducer with fiber optic coupling for recording the ion current from the measuring electrode of the Langmuir probe of the KI-1 installation of the Institute of Laser Physics of the Siberian Academy of Sciences is described. It is proposed to use a structure consisting of a plastic optical fiber 1 mm that transmits light at 650 nm, fast IF-E91 LEDs, and an IF-D91 photodiode for coupling. The results of laboratory testing of this high-speed converter with old one based on a AOD129A diode optocoupler under conditions close to the working conditions are compared.

The effect of two fluorinated derivatives of tetrahydrocarbazoles on mitochondrial en-zymes catalyzing the oxidative deamination of biogenic amines such as monoamine oxidase A and B (MAO-A and MAO-B) has been investigated. A dose-dependent effect of the studied compounds on the enzymatic activity MAO-A was shown. It was revealed that both com-pounds are MAO-B inhibitors. Inhibition mechanisms were established and MAO-B inhibi-tion constants were calculated. The above derivatives exhibit strong antioxidant and antirad-ical activity.

It is known that the conformation of human serum albumin binding sites is sensitive to pathological processes. In this work, changes in the physical–chemical properties of albumin binding sites in melancholic depression were studied. The K-35 fluorescent probe (dimethylaminonaphthalic acid N-carboxyphenylimide, CAPIDAN) was used as a reporter of these changes. It is shown that the fluorescence decay of K-35 depends on the state of the drug-binding sites of albumin. The kinetics of fluorescence decay were measured with a time resolution of approximately 30–50 ps. The parameters that characterize the fluorescence decay of K-35 in serum were reliably responsive to melancholic depression and the dynamics of its treatment. With melancholic depression, a decrease in the concentration of nonesterified long-chain fatty acids that are capable of affecting binding sites of serum albumin was observed. However, variations in the concentration of NEFA cannot be considered as a cause of the alterations of albumin binding sites. In addition to NEFA, other factors are likely to affect structural and physical-chemical properties of albumin in depression patients.

The antioxidant and antiradical properties of the tetra nitrosyl iron complex with thiosulfate ligands (TNIC) were studied in vitro in mouse brain homogenates. It was found for the first time that TNIC is an effective antioxidant. The effect of TNIC on the catalytic activity of mitochondrial enzymes cytochrome c oxidase and monoamine oxidase A was studied. It was shown for the first time that TNIC is an inhibitor of the catalytic activity of cytochrome c oxidase and monoamine oxidase A in animal brain mitochondria in vitro.

It becomes clear that the development of the pathological process can be followed by the conformational disturbances of the proteins, i.e. the orientation of a protein molecule in the space.

Proteins adsorbed on a surface may affect the interaction of this surface with cells. Here, we studied the binding of human serum albumin (HSA), fibrinogen (FBG) and immunoglobulin G (IgG) to PEGylated single-walled carbon nanotubes (PEG-SWCNTs) and evaluated the impact of PEG-SWCNT treated by these proteins on neutrophils in whole blood samples. Measurements of adsorption parameters revealed tight binding of proteins to PEG-SWCNTs. AFM was employed to directly observe protein binding to sidewalls of PEG-SWCNTs. Fluorescein-labeled IgG was used to ascertain the stability of PEG-SWCNT-IgG complexes in plasma. In blood samples, all plasma proteins mitigated damage of neutrophils observed just after blood exposure to PEG-SWCNTs, while only treatment of PEG-SWCNTs with IgG resulted in dose- and time-dependent enhancement of CNT-induced neutrophil activation and in potentiation of oxidative stress. Our study demonstrates the ability of adsorbed plasma proteins to influence neutrophil response caused by PEG-SWCNTs in whole blood.

The effect of two water-soluble derivatives of [60]fullerene (WS[60]FDs) on mitochondrial monoamine oxidase B (MAO-B) involved in oxidative deamination of biogenic amines has been investigated. The studied compounds were shown to be inhibitors of MAO-B. The inhibitory mechanism and the inhibition constants were determined. It was shown that WS[60]FDs I and II penetrate in lipid bilayer of membrane of phosphatidylcholine liposomes and localize in the regions of both polar head and fatty acid groups of phospholipids. The equilibrium constants of fluorescent dye—WS[60]FDs complexes were determined.

In the blood of children (n=16) with large thermal skin burns (20% of total body surface), luminol-dependent chemiluminescence (CL) of neutrophils stimulated with phorbol-12-myristate-13-acetate (PMA) and myeloperoxidase (MPO) activity in neutrophils and plasma were assayed in the early period (1-7 post-burn days). PMA-stimulated neutrophils in thermally injured patients produced higher CL than those in a reference group of healthy children (n=24), p0.01. MPO activity was elevated in neutrophils and plasma in 40% and 57% of patients' blood samples, respectively. The albumin fraction isolated from plasma of burned patients enhanced the PMA-stimulated CL response of blood samples from healthy volunteer. Our results suggest that the acute inflammatory response induced by thermal injury involves activation of neutrophils and is accompanied by MPO release into the plasma. MPO-mediated modification of serum albumin induces its capacity to prime neutrophils and thus to enhance further inflammatory reaction.U deteĭ (n=16) c termicheskimi ozhogami kozhi ploshchad'iu bolee 20% poverkhnosti tela v ranniĭ period (1-7 sutki) posle travmy izmeriali liuminol-zavisimuiu khemiliuminestsentsiiu (KhL) neĭtrofilov krovi, stimulirovannykh forbol-12-miristat-13-atsetatom (FMA), aktivnost' mieloperoksidazy (MPO) v neĭtrofilakh i plazme krovi. Uroven' KhL stimulirovannykh neĭtrofilov byl vyshe u patsientov, chem u zdorovykh deteĭ iz gruppy sravneniia (r0,01). V 40% obraztsov krovi patsientov obnaruzhena povyshennaia aktivnost' MPO v neĭtrofilakh, a v 57% obraztsov – aktivnost' MPO v plazme. Al'buminovaia fraktsiia plazmy obozhzhennykh usilivala KhL otvet krovi zdorovykh donorov na FMA. Poluchennye dannye svidetel'stvuiut o tom, chto ostraia vospalitel'naia reaktsiia v otvet na termicheskiĭ ozhog privodit k aktivatsii neĭtrofilov i soprovozhdaetsia vysvobozhdeniem MPO v plazmu krovi. Modifikatsiia belkov plazmy krovi, v pervuiu ochered' al'bumina, s uchastiem MPO mozhet stimulirovat' aktivatsiiu neĭtrofilov i provotsirovat' dal'neĭshee razvitie vospalitel'noĭ reaktsii organizma v otvet na travmu.

We studied membranotropic properties of NO donor 2-nitroxysuccinate 3-hydroxy-6-methyl-2-ethylpyridine and its structural analog succinate 3-hydroxy-6-methyl-2-ethylpyridine (Mexidol). It was shown that the compounds under study are incorporated into modeled membranes and form long-living complexes with pyrene in the region of fatty acid tails of phospholipids. Luminol-amplified chemiluminescence analysis showed that both compounds exhibited antiradical activity and in a concentration of 0.1 mM reduced chemiluminescence intensity by more than 70%. 2-Nitroxysuccinate 3-hydroxy-6-methyl-2-ethylpyridine inhibited catalytic activity of monoamine oxidase A more efficiently than its structural analogue Mexidol.

We have developed a self-reporting isothermal system for visual bacterial pathogen detection with single base resolution. The new DNA diagnostic is based on combination of peptide nucleic acid (PNA) technology, rolling circle amplification (RCA) and DNAzymes. PNAs are used as exceedingly selective chemical tools that bind genomic DNA at a predetermined sequence under nondenaturing conditions. After assembly of the PNA-DNA construct a padlock probe is circularized on the free strand. The probe incorporates a G-quadruplex structure flanked by nicking enzyme recognition sites. The assembled circle serves as a template for a novel hybrid RCA strategy that allows for exponential amplification and production of short single-stranded DNA pieces. These DNA fragments fold into G-quadruplex structures and when complexed with hemin become functional DNAzymes. The catalytic activity of each DNAzyme unit leads to colorimetric detection and provides the second amplification step. The combination of PNA, RCA, and DNAzymes allows for sequence-specific and highly sensitive detection of bacteria with a colorimetric output observed with the naked eye. Herein, we apply this method for the discrimination of Escherichia coli, Salmonella typhimurium, and Clostridium difficile genomes.

The effects of cognitive-stimulating substance BD-2 of the γ-carboline family and a hybrid compound based on fullerene C60 and attached BD-2 on various aspects of the behavior of animals were studied. The synthesized hybrid fullerene compound (HFC) has no side psychostimulating effect characteristic of BD-2 but fully retains the properties of a cognitive-stimulating agent. The design of hybrid compounds based on fullerene C60 and pharmacologically active groups can be one of the ways for optimizing therapeutically promising compounds.

Mechanisms of fluorescence quenching of aromatic chromophores by water are reviewed. The mechanisms include polarity of chromophore environment, proton or electron transfer between the excited chromophore and water. A hypothesis is proposed that the quenching can be a result of chromophore-solvent hydrogen bond breaking in the excited state.

We report the investigation of the molecular mechanisms responsible for the neuroprotective activity of water-soluble [60]fullerene derivatives (WS[60]FDs). It has been shown that WS[60]FDs influence the therapeutically important targets of the Alzheimer disease by inhibiting the catalytic activity of the monoaminooxidase B in vitro, decreasing the level of free radical species and behaving as positive modulators of AMPA receptors of Purkinje neurons in the cerebellum of rats. The cognitive stimulatory effects of WS[60]FDs were revealed in vivo through behavioural experiments in mice.

It is shown that human serum albumin, previously treated with HOCl (HSA-Cl), enhances luminol-dependent chemiluminescence of neutrophils activated by phorbol-12-myristate-13-acetate (PMA). The enzyme-linked immunosorbent assay revealed that addition of HSA-Cl to neutrophils promotes exocytosis of myeloperoxidase. Inhibitor of myeloperoxidase — 4-aminobenzoic acid hydrazide, without any effect on lucigenin-dependent chemiluminescence of neutrophils stimulated with PMA, effectively suppressed luminol-dependent chemiluminescence (IC50 = 20 μM) under the same conditions. The transfer of the cells from medium with HSA-Cl and myeloperoxidase to fresh medium abolished an increase in PMA-induced luminol-dependent chemiluminescence, but not the ability of neutrophils to respond to re-addition of HSA-Cl. A direct and significant (r = 0.75, p < 0.01) correlation was observed between the intensity of PMA stimulated neutrophil chemiluminescence response and myeloperoxidase activity in the cell-free media after chemiluminescence measurements. These results suggest the involvement of myeloperoxidase in the increase of neutrophil PMA-stimulated chemiluminescence response in the presence of HSA-Cl. A significant positive correlation was found between myeloperoxidase activity in blood plasma of children with severe burns and the enhancing effects of albumin fraction of the same plasma on luminol-dependent chemiluminescence of PMA-stimulated donor neutrophils. These results support a hypothesis that proteins modified in reactions involving myeloperoxidase under oxidative/halogenative stress, stimulate neutrophils, leading to exocytosis of myeloperoxidase, a key element of halogenative stress, and to closing a “vicious circle” of neutrophil activation at the inflammatory site.

SummaryWe present an approach for fluorescent in situ detection of short, single-copy sequences within genomic DNA in human cells. The single-copy sensitivity and single-base specificity of our method is achieved due to the combination of three components. First, a peptide nucleic acid (PNA) probe locally opens a chosen target site, which allows a padlock DNA probe to access the site and become ligated. Second, rolling circle amplification (RCA) generates thousands of single-stranded copies of the target sequence. Finally, fluorescent in situ hybridization (FISH) is used to visualize the amplified DNA. We validate this technique by successfully detecting six single-copy target sites on human mitochondrial and autosomal DNA. We also demonstrate the high selectivity of this method by detecting X- and Y-specific sequences on human sex chromosomes and by simultaneously detecting three sequence-specific target sites. Finally, we discriminate two target sites that differ by 2 nt. The PNA-RCA-FISH approach is a distinctive in situ hybridization method capable of multitarget visualization within human chromosomes and nuclei that does not require DNA denaturation and is extremely sequence specific.

Presented here are the methods used for detection of short, single-copy DNA sequences within human cells. These methods rely on (1) peptide nucleic acid (PNA) invasion of the target double-stranded DNA site to locally open a small single-stranded region within long DNA duplex, (2) site-specific formation of padlock probe, and (3) its rolling circle amplification for signal magnification. The signal detection is accomplished via either fluorescent in situ hybridization (FISH), flow cytometry (fluorescence-activated cell sorting, FACS), or droplet-based microfluidics. This methodology allows for sensitive and specific detection of DNA marker sequences without the need for DNA extraction and purification, making it possible to identify small genomic variations within individual human cells.

We report here a comparison of the effects of the pro-inflammatory cytokine interleukin-1β and the anti-inflammatory cytokine interleukin-4 on measures of blood albumin in rats with different types of behavioral activity in the open field. In the initial state, the total serum albumin concentration in active animals was significantly lower than that in passive individuals. However, the ratio of the effective albumin concentration to the total albumin concentration, which reflects its binding capacity, was greater in passive rats. Administration of interleukins led to decreases in the total and effective albumin concentrations in the blood of passive and especially active rats. There were no differences in the values of these parameters in animals with different types of behavioral activity after injections of interleukin-1β or interleukin-4. The initial intergroup differences in the binding capacity of serum albumin molecules were not seen after injections of these immunomodulators, because of the greater increase in this parameter in active individuals. These data indicate that interleukin-1β and interleukin-4 had differently directed effects on the properties of blood albumin binding centers in rats with different behavioral characteristics. The more marked effects of these cytokines on blood albumin parameters in behaviorally active rats than in passive individuals was linked with differences in the total albumin concentrations seen in these groups of animals in the initial state.

Albumin is a carrier of nonesterified long-chain fatty acids and many other ligands. The status of its binding centers was studied for various proportions of nonesterified long-chain fatty acids and albumin as exemplified by palmitic acid. The status of the binding center was tested by recording K-35 probe fluorescence decay in the subnanosecond band. This method showed the work of three types of centers. Palmitic acid enhanced binding activity of all centers, though to a different degree: if the palmitic acid/albumin proportion increased to 2-3, the probe binding to type 1 centers (located in the drug center I region) increased 1.5 times, while binding to type 3 centers increased more than 3-fold. Modification of these centers by nonesterified long-chain fatty acids was similar in the isolated human albumin preparation and in diluted blood serum. Hence, K-35 probe showed the actual status of various albumin centers, their binding capacity depending to a different measure on the fatty acid charge of albumin.

Patterns of the interaction between water-soluble polysubstituted fullerene derivatives (PFDs) and the lipid bilayer of phosphatidylcholine liposomes were investigated by applying triplet and fluorescent probes. Objective quantitative criteria have been proposed for the evaluation of membranotropic action of chemical substances, notably, fullerene derivatives that quench fluorescent probes with different localizations within the membrane. Thus, the defined criteria are the rate constants for the quenching of the fluorescence of triplet probes and the equilibrium constants for PFD-probe complexes, which characterize their stability. The localization of PFDs in the membrane was determined by comparing rate constants for the quenching of eosin phosphorescence and equilibrium constants for PFD-chromophore complexes. In addition, the efficiency of the interaction of PFDs with various sites of the phospholipid membrane has been seen to depend on the charge of addends that are attached to the polysubstituted derivatives.

Fluorescent probe N-(carboxyphenyl)imide of 4-(dimethylamino)naphthalic acid, K-35, is used as an indicator of structural changes of human serum albumin molecules in pathology. The probe occupies albumin binding pockets where the probe environment is of very high polarity; probably, the pockets contain protein polar groups and also water molecules. At the same time the rather small Stokes shift of K-35 fluorescence spectrum shows that the polar group motion is one-two orders of magnitude lower than the mobility of polar molecules in polar fluids. K-35 fluorescence decay in HSA can be described as a sum of three exponentials with time constants close to τ1 = 9 ns; τ2 = 3.6 ns and τ3 = 1.0 ns. The difference between excitation maxima of these three decay components shows that the environment of these three species of K-35 molecules has been different before excitation. Different τ values are probably a consequence of nonidentical structure of several binding sites, or the binding site(s) can have variable conformation.

The dynamics of changes in albumin transport function during hypochlorite-induced oxidation of isolated albumin in blood plasma and serum was studied with a fluorescent probe K-35. Binding of the probe K-35 to albumin was characterized by effective concentration of albumin. Oxidative modification of proteins was evaluated by the content of carbonyl products of protein oxidation and bityrosine fluorescent products. Oxidation with hypochlorite was accompanied by a decrease in the effective concentration of albumin in albumin, diluted plasma, and serum and accumulation of carbonyl products of protein oxidation and bityrosine fluorescent products. The decrease in the effective concentration of albumin during oxidation with hypochlorite can be explained by oxidative damage to albumin binding sites. Oxidative modification of probe K-35 binding sites with hypochlorite contributes to a decrease in effective concentration of albumin under pathological conditions.

The molecular mobility of the fluorescent probe, N-(carboxymethyl)imide of 4-(dimethylamino)naphthalic acid (K-35), in three types of binding site on a human serum albumin (HSA) molecule has been studied. Study of the time-resolved decay of K-35 polarized fluorescence in HSA has shown that probe molecules bound to different sites have different fluorescence decay times, which poses problems in interpreting the polarization curves. However, it has been found that, in the case of rather slow thermal rotation of the probe, the decay of the vertical and the horizontal components of polarized fluorescence can each be approximated with three exponentials corresponding to three types of binding site. The mobility of the probe in different sites was estimated. The mobility was different but in all cases hindered by tens of times relative to the rotation of K-35 in water. The slowest motion occurred in the sites of the first type localized in the region of the well known drug site I: there the rotational correlation time was at least 72 ns. In the sites of the second type, this time was about 40 ns, and in the sites of the third type, about 10 ns. The faster was the rotation, the higher was the fluorescence quenching rate. Probably, it is this motion that is responsible for different fluorescence decay times in different HSA sites.

The antioxidant properties of water-soluble amino acid derivatives of fullerene C60 (ADF) were studied. It was shown by the change in the concentration of malonic dialdehyde in rat brain mitochondria that the ADF are antioxidants. They were shown by the change in the luminol glow to possess antiradical activity, which is determined by the acceptor properties of the fullerene spheroid and is independent of the structure of the attached addends. Stereoselectivity of the antioxidant properties of the enantiomers of amino acid derivatives of fullerene C60 was found. The L-isomers of ADF inhibit lipid peroxidation, whereas the D-isomers do not inhibit. A reliable correlation between the development of cytomegalovirus (CMV) infection and the process of lipid peroxidation in the cell culture was established. An efficient inhibitor of the CMV infection from the class of amino acid derivatives of fullerene with antioxidant activity was obtained.

With the rapidly growing availability of the entire genome sequences of microbial pathogens, there is unmet need for increasingly sensitive systems to monitor the gene-specific markers for diagnosis of bacteremia that enables an earlier detection of causative agent and determination of drug resistance. To address these challenges, a novel FISH-type genomic sequence-based molecular technique is proposed that can identify bacteria and simultaneously detect antibiotic resistance markers for rapid and accurate testing of pathogens. The approach is based on a synergistic combination of advanced Peptide Nucleic Acid (PNA)-based technology and signal-enhancing Rolling Circle Amplification (RCA) reaction to achieve a highly specific and sensitive assay. A specific PNA-DNA construct serves as an exceedingly selective and very effective biomarker, while RCA enhances detection sensitivity and provide with a highly multiplexed assay system. Distinct-color fluorescent decorator probes are used to identify about 20-nucleotide-long signature sequences in bacterial genomic DNA and/or key genetic markers of drug resistance in order to identify and characterize various pathogens. The technique's potential and its utility for clinical diagnostics are illustrated by identification of S. aureus with simultaneous discrimination of methicillin-sensitive (MSSA) versus methicillin-resistant (MRSA) strains. Overall these promising results hint to the adoption of PNA-based rapid sensitive detection for diagnosis of other clinically relevant organisms. Thereby, new assay enables significantly earlier administration of appropriate antimicrobial therapy and may, thus have a positive impact on the outcome of the patient.

The efficiency of the therapy of psychiatric diseases is estimated using the fluorescence measurements of the conformational changes of human serum albumin in the course of medical treatment. The fluorescence decay curves of the CAPIDAN probe (N-carboxyphenylimide of the dimethylaminonaphthalic acid) in the blood serum are measured. The probe is specifically bound to the albumin drug binding sites and exhibits fluorescence as a reporter ligand. A variation in the conformation of the albumin molecule substantially affects the CAPIDAN fluorescence decay curve on the subnanosecond time scale. A subnanosecond pulsed laser or a Pico-Quant LED excitation source and a fast photon detector with a time resolution of about 50 ps are used for the kinetic measurements. The blood sera of ten patients suffering from depression and treated at the Institute of Psychiatry were preliminary clinically tested. Blood for analysis was taken from each patient prior to the treatment and on the third week of treatment. For ten patients, the analysis of the fluorescence decay curves of the probe in the blood serum using the three-exponential fitting shows that the difference between the amplitudes of the decay function corresponding to the long-lived (9 ns) fluorescence of the probe prior to and after the therapeutic procedure reliably differs from zero at a significance level of 1% (p < 0.01).

A study was made of the binding of a fluorescent probe K-35 (N-(carboxyphenyl)imide of 4-(dimethylamino)naphthalic acid), used as an indicator of albumin structural changes in pathology, to human serum albumin (HSA). Based on the data on the fluorescence decay of the probe, four types of site of K-35 binding to HSA have been recognized, which differ in fluorescence decay time (τ) and binding constant (K). Probe molecules bound to the first type of site have a decay time of 8–10 ns; this value corresponds to a high fluorescence quantum yield of about 0.7. These sites have a maximal binding constant, K 1 = 5 · 104 M−1. The τ2 of the second type of site is close to 3.6 ns and K 2 = 1 · 104 M−1, which is much lower than K 1; however, the number of these sites is several times greater. The number of sites of the third type and the binding constant are close to those of the second type, but the decay time τ3 is 1 ns, which is significantly lower than τ2. The binding of K-35 to sites of the second and the third types is characterized by a positive cooperativity. Their properties are similar but not completely identical. The total number of sites of these three types is about two per one HSA molecule. There are also one-two sites of the fourth type where bound K-35 molecules have a very short decay time τ4 ≪ 1, i.e., are virtually nonfluorescent, and K 4 = 1 · 104 M−1. The major contribution to the steady-state fluorescence is made by probe molecules bound to sites of the first and second types. As a rule, the concentration of albumin binding sites in blood is significantly higher than the concentration of metabolites and xenobiotics transferred by albumin. Therefore, the metabolite—or the probe in these experiments—is distributed among different sites in accordance with their K i n i values (n i is the number of sites of the i-th type per albumin molecule). The low occupancy of the sites results in an approximately equal number of K-35 molecules bound to different sites of types 1, 2, and 3. The competition of K-35 with phenylbutazone, a marker of the albumin drug-binding site I, allows one to suggest that the K-35 site of the first type is localized exactly in the drug site I region, while the sites of the second and third types are close to it.