[Digital PCR as a Highly Sensitive Diagnostic Tool: A Review].

Digital PCR (dPCR) is a nucleic acid quantification method that is widely used in genetic analysis. One of the most significant advantages of dPCR over other methods is the possibility of absolute quantitative determination of genetic material without construction of calibration curves, which allows one to detect even single molecules of nucleic acids, and, hence, provides early diagnosis of diseases. One specific characteristic of dPCR is the detection of the analyzed biological object in each microreaction, followed by the presentation of the analysis results in a binary system, thereby giving the method its name. The key aspects of developing the dPCR method, i.e., from the first devices based on microfluidic chip technology to modern systems capable of measuring a target at a concentration of up to 1 in 100000 copies are shown in the current work. We analyzed the data on the detection of various pathogens using dPCR, as well as summarizing various study results demonstrating the innovativeness of this method. Both the possibilities of multiplex dPCR analysis and its potential in clinical practice are presented. This review also addresses the issue of the role of dPCR in the development of noninvasive methods for analysis of oncological diseases. Possible ways of developing dPCR technology were emphasized, including its use as a "point-of-care" system.

Temperature anomalies of oscillating diffusion in ac-driven periodic systems.

We analyze the impact of temperature on the diffusion coefficient of an inertial Brownian particle moving in a symmetric periodic potential and driven by a symmetric time-periodic force. Recent studies have revealed the low-friction regime in which the diffusion coefficient shows giant damped quasiperiodic oscillations as a function of the amplitude of the time-periodic force [I. G. Marchenko et al., Chaos 32, 113106 (2022)1054-150010.1063/5.0117902]. We find out that when temperature grows the diffusion coefficient increases at its minima; however, it decreases at the maxima within a finite temperature window. This curious behavior is explained in terms of the deterministic dynamics perturbed by thermal fluctuations and mean residence time of the particle in the locked and running trajectories. We demonstrate that temperature dependence of the diffusion coefficient can be accurately reconstructed from the stationary probability to occupy the running trajectories.

Giant oscillations of diffusion in ac-driven periodic systems.

We revisit the problem of diffusion in a driven system consisting of an inertial Brownian particle moving in a symmetric periodic potential and subjected to a symmetric time-periodic force. We reveal parameter domains in which diffusion is normal in the long time limit and exhibits intriguing giant damped quasiperiodic oscillations as a function of the external driving amplitude. As the mechanism behind this effect, we identify the corresponding oscillations of difference in the number of locked and running trajectories that carry the leading contribution to the diffusion coefficient. Our findings can be verified experimentally in a multitude of physical systems, including colloidal particles, Josephson junction, or cold atoms dwelling in optical lattices, to name only a few.

ABILITY TO FORM BIOFILMS BY PYELONEPHRITIS CAUSATIVE AGENTS IN CHILDREN.

The work is dedicated to the study of biofilms formation process by main pyelonephritis causative agents in children in vitro using methods of light, fluorescent and scanning microscopy. To study biofilms formation bacteria were cultivated in liquid substratum on glass in polystyrene Petri dishes d=40mm. The study demonstrated that all isolates formed biofilms. Adhesion of bacteria planktonic forms took place on the first stage, intracellular matrix formation took place on the second stage, and biofilms formation took place on the third stage. During the study of E. coli and Proteus sрр bacteria preparations with the use of scanning and light microscopy ordered bacteria arrangement was seen in the form of separate structures or tiny clusters of bacterial cells united by matrix. During the study of the ability to form P. aeruginosa isolates biofilms with the help of scanning microscopy it was stated that the adhesion of separate bacterial cells occurs by conglomerates formation surrounded by matrix with further biofilms formation. Bacterial cells in the form of dense elongated sticks were seen under the film. P. аeruginosa isolates daily biofilms were stated to have dense structure in the form of gel. Packed biofilms areas with cells clusters with good fluorescence were found with the help of fluorescent microscopy. During daily K.рneumoniae isolates biofilms study by methods of scanning and fluorescent microscopy it was found that K.рneumoniae biofilms were covered with dense matrix and riddled with multiple canals in the form of apertures. During morphological peculiarities study of E. faecalis isolates biofilms formation with the use of scanning and fluorescent microscopy it was found that bacterial cells were densely packed and united by intracellular matrix under which bacteria of spherical shape were seen. Thus biofilms, the nature of which depends on the type of bacteria, are formed on the surface of conglomerates consisting of bacterial cells. Peculiarities of course and appearance of pyelonephritis chronic form and relapses in children is explained by biofilms formation.

[Embryology, anatomy and rare pathologies of the popliteal artery: Peculiarities of surgical treatment]. / Émbriologiia, anatomiia i redkie patologii podkolennoi arterii: osobennosti khirurgicheskogo lecheniia.

Knowledge of anatomical variations of the division of the popliteal artery and specific lesions of the arterial segment involved is necessary for the surgeon, traumatologist-orthopaedist, vascular surgeon. The article contains a review of recent literature data on the prevalence of different variants of branching patterns of the arteries of the crus, also providing a detailed discussion of embryological development of the arterial system of the lower extremities, in many ways explaining the appearance of rare pathologies of the popliteal artery, such as for example popliteal artery entrapment syndrome. Particular attention is paid to cystic damage of the popliteal artery, describing currently known theories of the development of this rare pathology, this is accompanied by sharing own experience in surgical treatment of the patients involved. Awareness of anatomical variants and peculiarities of embryonic development contributes to decreasing the possibility of iatrogenic damage of the popliteal artery during orthopaedic operations and to appropriate decision-making as to the method of revascularization.

[Optimal time of surgery for acute adhesive small bowel obstruction]. / Vybor sroka operativnogo lecheniia pri ostroi spaechnoi tonkokishechnoi neprokhodimosti (mul'titsentrovoe prospektivnoe randomizirovannoe issledovanie).

AIM: To define optimal terms of surgery for acute adhesive non-strangulatory small bowel obstruction. MATERIAL AND METHODS: The analysis included 703 publications from e-LIBRARI.RU (342 works) and NCBI (361 works) databases for acute adhesive intestinal obstruction. The vast majority of articles presented retrospective analysis of single-center experience. RESULTS: It has been established that short course of medication is predominantly used for acute adhesive intestinal obstruction in the Russian Federation. International studies point 2-5 days for conservative treatment. The advantages and disadvantages of short and long courses of medication were analyzed. Therefore, multicenter, prospective, randomized trial 'Comparison of early operative treatment (12-hour medication) and long-term conservative treatment (48 hours) for acute adhesive small bowel obstruction' (COTACSO) was planned and registered (Unique Protocol ID: 14121729). The study protocol involves clinical, laboratory and instrumental exclusion of strangulation, randomization and conservative treatment of 2 groups of patients for 12 and 48 hours. Patients will undergo surgical interventions if obstruction will be present by that date. The main endpoint is mortality rate in both groups. The end of the study is December 2020.

Enhanced diffusion with abnormal temperature dependence in underdamped space-periodic systems subject to time-periodic driving.

We present a study of the diffusion enhancement of underdamped Brownian particles in a one-dimensional symmetric space-periodic potential due to external symmetric time-periodic driving with zero mean. We show that the diffusivity can be enhanced by many orders of magnitude at an appropriate choice of the driving amplitude and frequency. The diffusivity demonstrates abnormal (decreasing) temperature dependence at the driving amplitudes exceeding a certain value. At any fixed driving frequency Ω normal temperature dependence of the diffusivity is restored at low enough temperatures, T

In situ synthesis and characterization of magnetic nanoparticles in shells of biodegradable polyelectrolyte microcapsules.

Hollow microcapsules with the shell composed of biodegradable polyelectrolytes modified with the maghemite nanoparticles were fabricated by in situ synthesis. The nanoparticles were synthesized from the iron salt and the base directly on the capsule shells prepared by "layer by layer" technique. An average diameter of the capsule was about 6.7 µm while the average thickness of the capsule shell was 0.9 µm. XRD, HRTEM, Raman and Mössbauer spectroscopy data revealed that the iron oxide nanoparticles have the crystal structure of maghemite γ-Fe2O3. The nanoparticles were highly monodisperse with medium size of 7.5 nm. The Mössbauer spectroscopy data revealed that the nanoparticles have marked superparamagnetic behavior which was retained up to room temperature due to slow spin relaxation. Because of that, the microcapsules can be handled by an external magnetic field. Both these properties are important for target drug delivery. Based on the Mössbauer spectroscopy data, the spin blocking temperatures TB of about 90K was found for the particles with size D≤5 nm and TB≈250 K for particles with D≥6 nm. The anisotropy constants K were determined using the superparamagnetic approximation and in the low temperature approximation of collective magnetic excitation.

[Development of a set of diagnostic test systems for analysis of expression of C-myc, mad1, max, p53, and E2F1 gene oncomarkers by the reverse transcription reaction-polymerase chain reaction alignment technique].

Based on the performed studies, the authors developed test systems to analyze the expression of mRNA of the p53, C-myc, mad1, max, and E2F1 genes. These test systems could reveal a statistically significant difference between follicular adenoma and carcinoma of the thyroid in their expression of p53 mRNA. It should be noted that the use of our developed test systems is promising when searching for the diagnostic and prognostic markers of cancer, analyzing, and creating the genetic networks characterizing this or that cancer.

[Puncture hystobiopsy with tissue telomerase activity measurement in preoperative thyroid nodes diagnostics].

Demonstrated, that puncture thyroid hystobiopsy is safe and informative method of preoperative thyroid nodes diagnostics. Telomerase activity in tissue samples was significantly higher in case of malignant thyroid disease, although a positive correlation of telomerase activity was also with the amount of lymphocytes in bioptates. Combination of thyroid hystobiopsy with tissue telomerase activity measurement proved to be an effective means of preoperative diagnostic of patients with nodular goiter.

[Transport processes of fluid exchange in the crystalline lens of the rabbit eye].

Processes of fluid exchange in the crystalline lens of the rabbit eye were investigated. The direction of movement of fluid in the crystalline lens was investigated from the movement of fluorescein by the method of "stopped diffusion". It has been found that the mechanism of fluid transport in the crystalline lens is active and is carried out by means of the Na-kappa-ATPase transport system. The energy necessary for the active transport of fluid inside the crystalline lens is in the range (1.5-6) x 10(-2) J. Owing to the active fluid transport, the pressure inside the crystalline lens constantly increases by 6 mm Hg. In rabbit's life-time, the movement of fluid in the crystalline lens occurs in the direction from the anterior to the posterior surface followed by the exit to vitreous humor.

[Transformation of soil organic matter in microarthropod community from the Northern Taiga of West Siberia].

Recolonization of defaunated soil by springtails as well as by gamasid and oribatid mites and the changes in organic matter content of soil were studied in the northern taiga. After a one-year exposure in gauze bags (1.7 mm mesh), the abundance of microarthropods was higher but the number of species was lower compared to the surrounding soil. Large surface and litter forms did not colonize the samples, while the number of small and/or soil forms was higher. Soil samples inaccessible for microarthropods (0.15 mm mesh) were depleted of organic carbon compared to both surrounding soil and recolonized samples. The content of humic and fulvic acids was higher in the samples inaccessible to microarthropods. Humification processes prevailed in soils in the absence of microarthropods.

[Comparative efficacy of fixed dose combinations of perindopril with indapamide and captopril with hydrochlorothiazide in patients with high risk hypertension].

Clinical effectiveness and tolerability of o.d. use of fixed dose combinations of perindopril (4 mg) with indapamide (1.25 mg) (Noliprel forte) and captopril (50 mg) with hydrochlorothiazide (25 mg) (Capozide) were compared in a randomized study on 40 patients with I-II degree high and very high risk hypertension. Study duration was 6 months, number of patients in each of parallel groups -- 20. Antihypertensive activity, ability to decrease left ventricular hypertrophy, to improve arterial elasticity and T/P parameter of perindopril (4 mg) -- indapamide (1.25 mg) combination was found to be superior to those of captopril (50 mg) -- hydrochlorothiazide (25 mg) combination.

Direction of fluid transport in the lens.

The direction of fluid flow in rabbits was studied in vivo by the distribution of fluorescein in eye structures. Fluorescein was administered into the central part of the lens. Fluorescein migrated from the anterior to posterior surface of the lens and then appeared in the vitreous body. Fluorescein did not migrate to the anterior surface and did not appear in the anterior chamber of the eye.

[Comparison of noliprel and caposide efficacy in patients with arterial hypertension of high risk].

AIM: To compare clinical efficacy and tolerance of fixed combinations of perindopril and indapamide (noliprel), capoten+hydrochlorotiaside (caposide) in arterial hypertension stage I-II of high and very high risk which failed prior monotherapy. MATERIAL AND METHODS: A blind randomized trial in parallel groups recruited 40 patients (20 patients each). The patients received 1 tablet a day noliprel (2 mg/0.625 mg) or caposide (50 mg/25 mg) for 6 months. Target pressure patients were counted. Speed of the pulse wave, blood lipids and electrolytes, left ventricular myocardium posterior wall thickness were estimated. RESULTS: By antihypertensive efficacy and ability to reduce left ventricular hypertrophy and to improve arterial elasticity, low-dose fixed combination (noliprel) was not inferior to caposide (high-dose fixed combination) while by T/P noliprel was more effective than caposide, it lowered cholesterol more but potassium level--less. CONCLUSION: Noliprel has the the same with caposide antihypertensive efficacy and ability to diminish LVH. It has benefits by action on lipid and electrolyte indices.

Quercetin immobilized on silica gel as a solid phase reagent for tin(IV) determination by using the sorption-spectroscopic method.

New chelating sorbents are prepared by 3,3',4',5,7-pentahydroxyflavone adsorption from butanol and acetone-hexane (1:4) solutions, characterized by isotherm of sorption, IR-spectroscopy and studied for pre-concentrating and sorption-spectroscopic determination of Sn(IV). The solid-phase Quercetin with satisfactory analytical characteristics was formed by adsorption from acetone-hexane (1:4) mixture. The quantitative recovery of Sn(IV) from aqueous solution with modified sorbent was observed at pH 1.8-2.2. The tolerance limits of heavy metal ions in the sorption of Sn(IV) are reported. The limit of Sn detection is 0.06 mg l(-1). The linearity of calibration graph has been observed up to 1.2 mg l(-1). The method has been applied to determine Sn in high purity zinc materials.

[Fibrinolytic activity of the lacrimal fluid in disordered choroid circulation in patients with arterial hypertension]. / Fibrinoliticheskaia aktivnost' sleznoi zhidkosti pri narusheniiakh khoroidal'nogo krovoobrashcheniia u bol'nykh s arterial'noi gipertoniei.

Fluorescent angiographic examination of the choroid and retinal circulation in 43 patients with arterial hypertension of different origin without signs of hypertensive retinopathy with low and normal values of the fibrinolytic activity of the lacrimal fluid (FALF) revealed a correlation between disorders of the choroid circulation (ischemic zones, delayed time of contrast staining of the choroid) and reduction of FALF. The results indicate that a reduction of FALF may be regarded as a prerequisite for the development of circulatory disorders in the choroid.

[Local fibrinolytic activity of the lacrimal fluid in patients with arterial hypertension]. / Issledovanie lokal'noi fibrinoliticheskoi aktivnosti sleznoi zhidkosti u bol'nykh arterial'noi gipertoniei.

Lacrimal fluid local fibrinolytic activity was measured in 101 patients with different variants of arterial hypertension. The studied parameter was found reduced in patients developing hypertensive retinopathy on the respective eye. A correlation was revealed between progress of hypertensive changes in the fundus oculi and reduction of lacrimal fluid local fibrinolytic activity. The results indicate that reduction of this parameter may be regarded as one of the prerequisites for the development of hypertensive retinopathy.