The Influence of Weaving Technologies on the Integral Characteristics of Synthetic Vascular Prostheses.

The aim of the study is to determine physical and structural properties of woven synthetic prostheses depending on the type of the weave. Materials and Methods: Ten vascular prostheses manufactured at the Science and Technology Park of the BNTU "Polytechnic" (Minsk, Republic of Belarus) have been analyzed. The prostheses differed in the type of weaving, duration and temperature of thermal fixation during crimping. Three samples had a single-layer structure and 7 samples had a double-layer structure. Tests for water permeability, resistance to radial bending, and porosity of the prostheses have been performed. Results: The single-layer woven prostheses have demonstrated a low level of water permeability: the best result was shown by sample No.1: 80 [77.1; 80.5] ml/min/cm2. A strong direct correlation was revealed for these prostheses: the larger the pore diameter, the greater permeability (r=0.778; p=0.05). The single-layer woven prostheses appeared to be most resistant to radial bending, samples No.1 and 3 had no deformations at the minimum radius of the cylinder (r<4 mm), sample No.2 showed deformation on the cylinder with r=5 mm. For the single-layer prostheses, a strong negative correlation was noted (r=‒0.97; p=0.04) between the density of the warp threads and the kinking radius.All double-layer prostheses have demonstrated higher water permeability and weak resistance to deformation during radial bending. Samples No.4 and 8 were found to have minimum and maximum water permeability of 276.5 [258.3; 288.4] and 538.8 [533.3; 564.3] ml/min/cm2, respectively. The minimum kinking radius (7 mm) was shown by samples No.9 and 10. The worst results were demonstrated by sample No.6, which was deformed with minimal bending. Conclusion: Samples with ordinary plain weave have a low level of water permeability and high resistance to radial deformation, which makes them look most promising for the application in vascular surgery.

Effects of monacolin K-containing nutraceutical on cholesterol homeostasis re-establishment and CVD risk reduction in hypercholesterolemic subjects.

OBJECTIVE: Hypercholesterolemia is caused by cholesterol homeostasis (CH) disruption, and it contributes to cardiovascular diseases pathogenesis and progression. Status of CH can be assessed by measuring serum concentrations of non-cholesterol sterols (NCS) which serve as cholesterol synthesis and absorption surrogate markers. Monacolin K, isolated from red yeast rice, influences cholesterol synthesis by inhibiting HMG-CoA reductase activity and reduces serum total cholesterol (TC) concentration. PATIENTS AND METHODS: This longitudinal study included 30 hypercholesterolemic patients, with systematic coronary risk estimation (SCORE) values <10%, who received 3-months-long supplementation with nutraceutical mixture containing monacolin K, and vitamins C, B1 and K2. Serum NCS were quantified by HPLC-MS/MS method. Atherogenic indexes were calculated from lipid status parameters concentrations. Albumin degradation inhibition test was conducted to estimate in vitro anti-inflammatory activity of the nutraceutical mixture, whereas in vitro antioxidant activity was measured in serum enriched with prooxidants and antioxidants. RESULTS: TC, LDL-cholesterol (LDL-C), and triglycerides (TG) concentrations (p<0.001), as well as atherogenic indexes and SCORE values (p<0.001, p<0.01, respectively) were lowered following the supplementation. Concentrations of cholesterol synthesis markers were decreased (p<0.001), whereas levels of cholesterol absorption markers remained unchanged after the supplementation. Reduction in cholesterol synthesis went alongside reductions in lipid status parameters and atherogenic indexes. In vitro analyses showed certain anti-inflammatory and antioxidant activity of the nutraceutical. CONCLUSIONS: These results suggest that supplementation with monacolin K containing nutraceutical favorably influences lipid status parameters and atherogenic indexes by acting on cholesterol synthesis. Anti-inflammatory and antioxidant effects of this unique nutraceutical mixture may exhibit beneficial pleiotropic effects.

Ab ovo: Factors Affecting the Radial Stiffness of Thoracic Aorta Stent-Grafts.

The aim of the investigation was to study the factors influencing the radial stiffness of the thoracic aorta stent-grafts with the stent elements made of nitinol tubes by laser cutting and thermal shape setting. Materials and Methods: The work used stent elements made by different technologies by two different manufacturers from a nitinol tube with a wall thickness of 0.5 mm (E1) and 0.4 mm (E2), with a final diameter of 20 mm. Height of cells E1 - 15 mm, E2 - 12.5 mm. The stents were manually attached to a tubular woven non-crimped base (PTGO Sever, Russia) with a 6/0 suture, resulting in either single or continuous stitches. In the RLU124 radial force tester (Blockwise Engineering LLC, USA), each of the four stent-grafts, as well as their individual stent elements, were compressed by 10 mm from the initial diameter. The dependence of the radial forces on deformation under loading and unloading was graphically presented. The temperature and enthalpy of phase transitions of nitinols into the austenite (Af) and martensitic (Mf) phases were studied using differential scanning calorimetry (DSC-3; Mettler Toledo, USA). All indicators were compared with the characteristics of two commercial models - Cronus (China) and E-vita Open Plus (Germany). Results: Four prototypes of SibHybrid stent-grafts were tested; those differed in their stent elements, distances between them, and the type of sutures (single or continuous). The stent elements of the models studied differed in the values of Af, Mf, and the enthalpy of phase transitions of nitinols. The hardest stent was the E2 prototype. The fixation of stent elements to the woven fabric in the graft increased the radial force by 4.0-5.5 times. During compression by 50 and 20% of the original diameter, the SibHybrid models developed radial force 4.5-6.0 times greater compared with the E-vita Оpen Plus model. The radial force values of SibHybrid models were almost the same as for the Cronus and models at 20% compression. Using continuous twining round suturing increased the radial force by about 10 N; accordingly, SibHybrid E2 had the highest radial force because it was fixed by a continuous suture. The density of the stent elements fixed on the fabric did not affect the radial force of the stent-graft as a whole. Conclusion: In the manufacture of stent elements from nitinol tubes, the main factor determining the radial stiffness is the technology of nitinol shape setting. With the standard technology of thermal shape setting, radial force can be changed by varying the height of the structure cell element and the cross-sectional area of the cell bars, as well as the suturing technique.

Toxicity study of DE-EDCP as a potential drug for cancer therapy: Toxicity profile of DE-EDCP.

It was reported that novel O, O'-diethyl-(S, S)-ethylenediamine- N, N'-di-2-(3-cyclohexyl) propanoate dihydrochloride (DE-EDCP) displayed in vitro antiproliferative activity on several human and mouse cancer cell lines, which was comparable to that of the prototypical anticancer drug cisplatin. In order to reveal its toxicity profile, acute and repeated-dose toxicity studies were performed in Naval Medical Research Institute (NMRI) Han mice. The intravenous LD50 values of DE-EDCP were found to be 95.3 and 101.3 mg/kg body weight in female and male mice, respectively. In the subacute toxicity study, DE-EDCP was administered intravenously at the doses of 15, 25, and 40 mg/kg/day for a period of 28 days. There were no adverse effects on general condition, growth, feed and water consumption, and hematological parameters. There was a significant increase in urea and alanine aminotransferase in female mice and aspartate aminotransferase and alkaline phosphatase in both genders in 40 mg/kg/day dose-treated group. The histopathological changes confined to the liver and kidney, but in other organs were not found. Satellite group revealed that changes in the kidney and liver were less pronounced, suggesting their reversibility. Interactions with DNA could also be of importance for understanding DE-EDCP toxic side effects. Hyperchromic effect obtained with ultraviolet-visible, suggested electrostatic interactions between DE-EDCP and calf thymus DNA. The toxicity testing of DE-EDCP was conducted to predict human outcomes.

[Clinical and cost effectiveness of percutaneous coronary intervention for patients with chronic coronary artery disease during overnight hospitalization].

AIM: To evaluate cost effectiveness of coronary endovascular treatment in patients with stable IHD during "one-night" hospitalization. MATERIALS AND METHODS: Using the cost-minimization analysis direct medical cost of coronary endovascular treatment in patients with stable IHD during the "one-night" hospitalization was compared with the "classic" hospitalization. RESULTS: The most cost-effective strategy for hospitalization of patients for transcutaneous coronary intervention (TCI) with stenting was the "one-night" hospitalization. Differences in direct medical costs (DMC) were statistically significant (p=0.01) in favor of the patient group hospitalized for one night. CONCLUSION: The "one-night" hospitalization plan for patients with stable IHD to undergo TCI with stenting increases the cost-effectiveness due to the decreased number of days of stay in the hospital and the associated decrease in cost of in-patient maintenance, which resultes in considerable financial savings (Δ between the hospitalization plans was 21.2 % in favor of the "one-might" hospitalization). This Δ indicates high cost effectiveness of the selected approach.

A new model to determine lipophilicity of 1,2-ethanediamine-N,N'-di-2-(3-cyclohexyl)propanoic acid and 1,3-propanediamine-N,N'-di-2-(3-cyclohexyl)propanoic acid derivatives with antiproliferative activity by combining shake flask procedure and UHPLC-MS method.

Fourteen compounds representing ester derivatives of (S,S)-1,2-ethanediamine-N,N'-di-2-(3-cyclohexyl) propanoic and (S,S)-1,3-propanediamine-N,N'-di-2-(3-cyclohexyl)propanoic acids, expressing antiproliferative activity in vitro were examined. The objective of this study was to determinate their lipophilicity data, and also to ensure a mathematical model for prediction lipophilicity data of potential in vivo metabolites and new derivatives of (S,S)-1,2-ethanediamine-N,N'-di-2-(3-cyclohexyl)propanoic acid, based on chromatographic parameters. Experimentally, lipophilicity data were obtained by a traditional shake flask procedure and an ultra-high performance liquid chromatographic tandem mass spectrometry (UHPLC-MS) method. A correlation between the partition coefficient n-octanol/water (logD7,4) and chromatographic data (CHI, 0), and also, between logD7,4 and retention time was investigated. A very good correlation (r2=0.8969) was found between lipophilicity parameters 0 and logD7,4 obtained using UHPLC-MS and shake flask methods: logD7,4 = (0.11±0.01)×0 + (1.25±0.20)×Nc - (9.19±1.18); statistical parameter F=47.84; significance of F = 3.74×10-6, Nc=number of C atoms between two amino groups (Nc=2 for 1,2-ethanediamine derivatives and Nc=3 for 1,3-propanediamine derivatives). The model predictivity power was determined by cross validation leave one out (LOO) technique, and expressed by the term Q2, was 0.89. The developed model has good predictivity power for prediction lipophilicity data of potential in vivo metabolites of the investigated compounds, such as novel 1,2-ethanediamine and 1,3-propanediamine N,N'-di-2-(3-cyclohexyl)propanoic acid derivatives. Also, the lipophilicity data obtained in the present study correlated with the antiproliferative activity of the investigated substances shown previously in in vitro studies.

Electromagnetic wave band structure due to surface plasmon resonances in a complex plasma.

The dielectric properties of complex plasma containing either metal or dielectric spherical inclusions (macroparticles, dust) are investigated. We focus on surface plasmon resonances on the macroparticle surfaces and their effect on electromagnetic wave propagation. It is demonstrated that the presence of surface plasmon oscillations can significantly modify plasma electromagnetic properties by resonances and cutoffs in the effective permittivity. This leads to related branches of electromagnetic waves and to the wave band gaps. The conditions necessary to observe the band-gap structure in laboratory dusty plasma and/or space (cosmic) dusty plasmas are discussed.

[N-terminal pro-brain natriuretic peptide levels and diastolic dysfunction in patients with early rheumatoid arthritis before the administration of disease-modifying antirheumatic drugs].

AIM: To determine N-terminal pro-brain natriuretic peptide (NT-proBNP) levels in patients with early rheumatoid arthritis (RA) before the use of disease-modifying antirheumatic drugs (DMARDs); to compare NT-proBNP values with traditional risk factors (TRF), cardiovascular diseases (CVD), inflammatory markers, and left ventricular (LV) diastolic dysfunction (DD). SUBJECTS AND METHODS: The investigation enrolled 74 patients with a valid RA diagnosis (the 2010 ACR/EULAR criteria), 56 (74%) women, median (Me) age, 54 years; disease duration, 7 months; seropositive for IgM rheumatoid factor (87%) and/or anti-cyclic citrullinated peptide antibodies (100%) with no history of the use of DMARDs and glucocorticosteroids. Duplex scanning and echographic findings were used to assess TRF for CVD and carotid artery atherosclerosis (CAA) in all the patients with early RA prior to therapy. An E/A ratio was used as a criterion for LVDD. RESULTS: NT-proBNP concentrations in patients with early RA proved to be higher than those in the control group (p<0.0001). Higher-than-normal NT-proBNP levels were seen in 36 (49%) patients. The patients with early RA and elevated NT-proBNP values were older and had a higher body mass index (BMI) than those with normal NT-proBNP levels. Those with elevated NT-proBNP concentrations were more frequently found to have CAA, coronary calcification, and coronary heart disease; their intima-media thickness was also larger and C-reactive protein (CRP) levels higher than in those with normal NT-proBNP values. There were correlations between NT-proBNP levels and erythrocyte sedimentation rate, CRP, simplified disease activity index, and clinical disease activity index. Multivariate analysis revealed that chronic heart failure (CHF), CAA, CRP and low-density lipoprotein (LDL) levels, and BMI correlated with NT-proBNP concentrations. LVDD was detected in 35 (48%) patients with early RA. The level of NT-proBNP in patients with DD was higher than in those without DD. Higher-than-normal NT-proBNP values were observed in 23 (65%) and 12 (32%) patients with and without LVDD, respectively. The optimal NT-proBNP level for CHF detection was equal to 237.4 pg/ml (86% sensitivity and 85% specificity); the area under the ROC curve was 0.879. CONCLUSION: Just at the early disease stage, the patients are noted to have a high NT-proBNP level that is influenced by higher BMI, low LDL levels, CAA, CHF, and high CRP values. In the patients with early RA, the diagnostically significant NT-proBNP concentration for CHF detection was higher (237 pg/ml) than in those without RA (125 pg/ml). The patients with early RA should undergo NT-proBNP determination, LVDD screening, correction of TRF for CVD, atherosclerosis treatment, and remission achievement.

The effect of lipophilicity on the hepatobiliary properties of iminodiacetic acid derivatives in the conditions of hyperbilirubinemia.

The partition coefficients (log P) of theoretically possible alkyliodinated iminodiacetic acid (IDA) derivatives and commercial IDA derivatives were calculated using two computer programs: ChemSketch Log P and ChemOffice Ultra. Newly synthesized ligands (DIETHYLIODIDA and DIISOPROPYLIODIDA) with the highest calculated log P were labeled with technetium-99m. The biodistribution and the influence of bilirubin on their biokinetics were investigated in rats and compared to corresponding results for commercial (99m)Tc-BROMIDA. Log P of (99m)Tc-complexes of synthesized ligands were determined experimentally as well as the protein binding. In comparison to (99m)Tc-BROMIDA, (99m)Tc-DIETHYLIODIDA has: (a) better biliary excretion (2.76±0.15%ID/g versus 1.83±0.10%ID/g); (b) faster hepatic clearance (2.90±0.21%ID/g versus 7.47±0.70%ID/g) and decreased biliary excretion (for 14% versus 22%) in conditions of hyperbilirubinemia after 15min. It is proved that (99m)Tc-DIISOPROPYLIODIDA has a prolonged hepatic transit time and decreased biliary excretion.

The novel phenylpropiophenone derivates induced relaxation of isolated rat aorta.

Our aim was to define how different chemical properties of newly developed phenylpropiophenone derivates (PhPds) influenced their potency and efficacy to relax rat aorta. A contribution of ion channels in the PhPds and propafenone mechanism of vasodilatation was tested. PhPds were syntethysed by substitution in the benzyl moiety with -F, -CH3 or -CF3 groups on the ortho or para position. The vasodilatation by PhPds was examined on the rings of rat aorta precontracted with phenylephrine. In order to test involvement of voltage-gated Na+ and K+ channels and L-type Ca2+ channels in a mechanism of action of PhPds, we used their blockers: lidocaine, nifedipine and 4-aminopiridine, respectively. Aorta was more sensitive to 5-ortho-trifluoromethyl derivate than to propafenone and other PhPds. The 5-para-methyl derivate had lower potency and efficacy than propafenone and other PhPds. Lidocaine did not influenced relaxation induced by PhPds, but slightly inhibited the effect of propafenone. The 4-aminopiridine only inhibited relaxation induced by 5-para-methyl derivate. Nifedipine inhibited relaxation of the rat aorta induced by 5-ortho-trifluoromethyl derivate and by propafenone. Introduction of 5-ortho-trifluoromethyl and 5-para-methyl group in the benzyl moiety of propafenone molecule changed its potency, efficacy and mechanism of action in the rat aorta. The 4-aminopiridine- and nifedipine sensitive ion channels are involved in mechanism of action of 5-para-methyl and 5-ortho-trifluoromethyl derivate. The introduction of other tested groups in the benzyl moiety does not affect pharmacological properties of the PhPds in relation to propafenone.

Quantum-tunneling-enhanced charging of nanoparticles in plasmas.

The role of quantum tunneling effect in the electron accretion current onto a negatively charged grain immersed in isotropic plasma is analyzed, within the quasiclassic approximation, for different plasma electron distribution functions, plasma parameters, and grain sizes. It is shown that this contribution can be small (negligible) for relatively large (micron-sized) dust grains in plasmas with electron temperatures of the order of a few electronvolts, but becomes important for nanosized dust grains (tens to hundreds of nanometers in diameter) in cold and ultracold plasmas (electron temperatures at approximately tens to hundreds of Kelvin), especially in plasmas with depleted high-energy "tails" in the electron energy distribution.

Charge on the dust in the plasma.

The grain in the plasma gets charged until the net plasma flux to the grain surface vanishes. In the absence of any analytical formula, this ambipolar condition is utilized to compute the grain charge indirectly. The present work proposes an approximate analytical expression for the grain charge that is exact in the asymptotic limit and in which the relative error between analytical and numerically computed solutions is less than 3%. Using this formula, we show that, much like the plasma sheath, the Bohm criterion is satisfied near the dust surface.

Shielding of a moving test charge in a quantum plasma.

The linearized potential of a moving test charge in a one-component fully degenerate fermion plasma is studied using the Lindhard dielectric function. The motion is found to greatly enhance the Friedel oscillations behind the charge, especially for velocities larger than half of the Fermi velocity, in which case the asymptotic behavior of their amplitude changes from 1/r3 to 1/r2.5. In the absence of the quantum recoil (tunneling) the potential reduces to a form similar to that in a classical Maxwellian plasma, with a difference being that the plasma oscillations behind the charge at velocities larger than the Fermi velocity are not Landau damped.

Instability of the ionization-absorption balance in a complex plasma at ion time scales.

The stability of ion plasma perturbations is investigated in a homogeneous isotropic complex plasma, where a balance between plasma creation due to ionization and plasma loss due to the absorption on dust particles has been reached. The analysis is performed on the basis of a self-consistent fluid description including dust charge variations and ion-neutral friction. It is shown that the stability depends primarily on the nature of the ionization source. For an ionization source proportional to the electron density, an instability takes place at wave numbers below a certain threshold, and the instability mechanism is explained in detail. No instability is found for a constant ionization source.

In vitro evaluation of yoghurt starter lactobacilli and Lactobacillus rhamnosus GG adhesion to saliva-coated surfaces.

AIM: The aim of the study was to evaluate the adhesion of Lactobacillus delbrueckii subsp. bulgaricus and Lactobacillus rhamnosus strain GG to saliva-coated surfaces in vitro. METHODS: Fifteen radiolabeled dairy L. delbrueckii subsp. bulgaricus strains and L. rhamnosus GG were tested for their ability to adhere to saliva-coated hydroxyapatite beads and polystyrene microtiter plates and the radioactivity was measured by liquid scintillation counter. The effects of lysozyme on the adhesion of lactobacilli and of pretreatment with lactobacilli on the adhesion of Streptococcus sanguinis were also assessed. RESULTS: All strains tested adhered to saliva-coated surfaces but with significantly different binding frequencies. The adhesion of the L. delbrueckii subsp. bulgaricus strains remained lower in comparison to L. rhamnosus strain GG. One L. delbrueckii subsp. bulgaricus strain showed binding frequency comparable to S. sanguinis. Lysozyme pretreatment of the samples significantly increased lactobacillus adhesion to saliva-coated surfaces. CONCLUSION: The present results showed significant variations in the adhesion capacity of the Lactobacillus strains studied. Adhesion to oral surfaces is of primary importance for bacterial colonization in the mouth. Only one of the L. delbrueckii subsp. bulgaricus dairy starter culture strains investigated had a high adhesion percentage. This strain might then be considered for further investigations in the oral environment.

Dynamics of two particles in a plasma sheath.

The stability and arrangements of two dust particles in a plasma are investigated in terms of the Hamiltonian of the system. It is shown that the Hamiltonian description of a non-Hamiltonian system can be used to predict qualitative features of possible equilibria in a variety of confinement potentials and can provide useful plasma diagnostics. The results compare favorably with those of simulations and are used to create experimental hypotheses. In particular, the symmetry-breaking transition of the particles as they leave the horizontal plane admits a Hamiltonian description which is used to elucidate the wake parameters.

Numerical simulations of potential distribution for elongated insulating dust being charged by drifting plasmas.

The potential distributions surrounding elongated insulating dust grains being charged by supersonic plasma flows are studied using the particle-in-cell method. The plasma flow introduces an asymmetry in the dust charging. This leads to a complex surface charge distribution on the dust, and to ion focusing in the wake region. We demonstrate that the charge and potential distributions on the dust surface and the wake behind the dust depend on the rod length and dust inclination angle with respect to the flow. The role of the surface charge distribution in the interactions between insulating rods in a plasma is discussed. Our simulations are carried out in two spatial dimensions, treating ions and electrons as individual particles.

Wake behind dust grains in flowing plasmas with a directed photon flux.

The wake behind conducting dust grains in a supersonic plasma flow with a directed photon flux is studied by the particle-in-cell method. The electron emission leads to a positive charge on the dust. The resulting plasma wake differs significantly from the case without photoelectrons. This wake is studied for different photon fluxes and different angles between the incoming unidirectional photons and the plasma flow velocity. The simulations are carried out in two spatial dimensions, treating ions and electrons as individual particles.

Study of valsartan interaction with micelles as a model system for biomembranes.

In this study, the interaction of valsartan (VAL), an angiotensin II receptor antagonist, with cationic surfactant cetyltrimethylammonium bromide (CTAB) was investigated. The effect of cationic micelles on spectroscopic and acid-base properties of VAL was carried out using UV spectrophotometry at physiological conditions (pH 7.4). The binding of VAL to CTAB micelles implied a shift in drug acidity constant (pK(a)(water)-pK(a)(micelle)=1.69) proving the great affinity of VAL dianion for the positively charged CTAB micelle surface. To quantify the degree of VAL/CTAB interaction, two constants were calculated by using mathematical models: micelle/water partition coefficient (K(x)) and drug/micelle binding constant (K(b)). The decrease of K(x) with VAL concentration, obtained by using pseudo-phase model, is consistent with an adsorption-like phenomenon. From the dependence of differential absorbance at lambda=295 nm on CTAB concentration, by using mathematical model that treats the solubilization of VAL dianion as its binding to specific sites in the micelles (Langmuir adsorption isotherm), the binding constant (K(b)=(2.50+/-0.49)x10(4)M(-1)) was obtained. Binding constant VAL/CTAB was also calculated using micellar liquid chromatography (MLC).

Superfluidlike motion of an absorbing body in a collisional plasma.

Motion of a small charged absorbing body (micrograin) immersed in a stationary weakly ionized high pressure plasma environment is considered. It is shown that the total frictional (drag) force acting on the grain can be directed along its motion, causing the grain acceleration. At some velocity, the forces associated with different plasma components can balance each other, allowing free undamped superfluid motion of the grain. The conditions when such behavior can be realized and the possibility of a superconductive grain current are discussed in the context of complex (dusty) plasmas.