Mathematical modeling in assessing the risk of restenosis after carotid endarterectomy.

Carotid endarterectomy is the main way to combat atherosclerosis of the carotid arteries, which disrupts cerebral circulation. The generally accepted marker of atherogenesis risk are hemodynamic indices associated with near-wall shear stress. The purpose of the work is to conduct a comparative analysis of hemodynamic indices in various carotid bifurcation models. The influence of a virtual change in the geometric shape of the model in order to optimize hemodynamic indices is also being studied. On the basis of computed angiography data, carotid bifurcation models are constructed, in which critical zones of hemodynamic indices are built using computational fluid dynamics. A comparative analysis of the critical zones for different classes of models is carried out. Comparison of averaged indices for critical zones between 'normal' and post-operative groups gave more than 5-x worse results for the latter. The same results for the near-bifurcation parts of the zones give a 25% better result for postoperative models. Virtual 'removal' of insignificant plaques leads to a deterioration of the indices of up to 40% in the places of the plaque's former location. The described method makes it possible to build the indices critical zones and compare them for various types of models. A technique for virtual changing the shape of a vessel (virtual surgery) is proposed. The novelty of the approach lies in the use for comparative analysis both real vessel models and hypothetical 'improved' virtual ones, as well in the proposed division of post-operative model's critical zones into subzones of different genesis.

[Cytochrome bd as Antioxidant Redox Enzyme].

One of the main functions of enzyme complexes that constitute electron transport (respiratory) chains of organisms is to maintain cellular redox homeostasis by oxidizing reducing equivalents, NADH and quinol. Cytochrome bd is a unique terminal oxidase of the chains of many bacteria including pathogenic species. This redox enzyme couples the oxidation of ubiquinol or menaquinol by molecular oxygen to the generation of proton motive force, a universal energy currency. The latter is used by the organism to produce ATP, another cellular energy currency, via oxidative phosphorylation. Escherichia coli contains two bd-type oxidases, bd-I and bd-II, encoded by the cydAB and appCB operons, respectively. Surprisingly, both bd enzymes make a further contribution to molecular mechanisms of maintaining the appropriate redox balance in the bacterial cell by means of elimination of reactive oxygen species, such as hydrogen peroxide. This review summarizes recent data on the redox-modulated H2O2-scavenging activities of cytochromes bd-I and bd-II from E. coli. The possibility of such antioxidant properties in cytochromes bd from other bacteria is also discussed.

[Risk factors for venous thromboembolic complications in elderly and senile patients with diabetes mellitus planned for spinal surgery.]

The search for literature sources in domestic and foreign databases showed the absence of works devoted to the study of risk factors for venous thromboembolic events (VTE) in patients of the older age group with diabetes mellitus who are planned to undergo surgical interventions on the spine, which was the impetus for this study. The aim of the study was to study the risk factors for VTE in elderly and senile patients with diabetes mellitus who are scheduled for spinal surgery. A single-center retrospective study included 119 elderly and senile patients (64 men, 55 women, mean age 74,2±6,5 years) who underwent various surgical interventions on the spinal column. According to the binary logistic regression model, the following parameters are statistically significantly associated with the development of VTEC in the studied group of respondents: age of patients over 75 years (p=0,048), HbA1C levels over 7,5% (p=0,007) and D-dimer over 0,5 mg /l FEU (p=0,034), as well as high risk (5 points or more) of VTE according to Caprini scale (p=0,012). In order to reduce the incidence of VTE in elderly and senile patients with diabetes mellitus who are planned to perform surgical interventions on the spine, it is necessary to verify the above clinical and laboratory parameters in the early stages of hospitalization.

Measurement of Direct-Photon Cross Section and Double-Helicity Asymmetry at sqrt[s]=510 GeV in p[over →]+p[over →] Collisions.

We present measurements of the cross section and double-helicity asymmetry A_{LL} of direct-photon production in p[over →]+p[over →] collisions at sqrt[s]=510 GeV. The measurements have been performed at midrapidity (|η|<0.25) with the PHENIX detector at the Relativistic Heavy Ion Collider. At relativistic energies, direct photons are dominantly produced from the initial quark-gluon hard scattering and do not interact via the strong force at leading order. Therefore, at sqrt[s]=510 GeV, where leading-order-effects dominate, these measurements provide clean and direct access to the gluon helicity in the polarized proton in the gluon-momentum-fraction range 0.02

[Computer modeling of the area of carotid endarterectomy with patches of various forms]. / Sposob komp'yuternogo modelirovaniya zony klassicheskoi karotidnoi endarterektomii s primeneniem zaplat razlichnoi formy.

OBJECTIVE: To describe geometric models of carotid artery bifurcation and computer modeling of carotid endarterectomy (CEA) with patches of various configurations. MATERIAL AND METHODS: The method was demonstrated on a reconstructed model of intact vessel based on preoperative CT of the affected vessel in a certain patient. Blood flow is modeled by computational fluid dynamics using Doppler ultrasound data. Risk factors were assessed considering hemodynamic parameters of vascular wall associated with WSS. RESULTS: We studied hemodynamic results of 10 virtual CEA with patches of various shapes on the example of a reconstructed intact artery in a particular patient. Patch implantation is aimed at prevention of carotid artery narrowing since simple suture without a patch can reduce circumference of the artery by 4-5 mm. This result adversely affects blood flow. On the other hand, too wide a patch creates aneurysm-like deformation of internal carotid artery bulb. It is not optimal due to a large recirculation zone. It was found that patch width approximately equal to 3 mm ensures an optimal hemodynamic result. Deviations from this median value, both upward and downward, impair hemodynamics while the absence of a patch results the worst result. CONCLUSION: The proposed computer modeling technique is able to provide a personalized patch selection for CEA with low risk of restenosis in long-term follow-up period.

Exchange scaling of ultrafast angular momentum transfer in 4f antiferromagnets.

Ultrafast manipulation of magnetism bears great potential for future information technologies. While demagnetization in ferromagnets is governed by the dissipation of angular momentum1-3, materials with multiple spin sublattices, for example antiferromagnets, can allow direct angular momentum transfer between opposing spins, promising faster functionality. In lanthanides, 4f magnetic exchange is mediated indirectly through the conduction electrons4 (the Ruderman-Kittel-Kasuya-Yosida (RKKY) interaction), and the effect of such conditions on direct spin transfer processes is largely unexplored. Here, we investigate ultrafast magnetization dynamics in 4f antiferromagnets and systematically vary the 4f occupation, thereby altering the magnitude of the RKKY coupling energy. By combining time-resolved soft X-ray diffraction with ab initio calculations, we find that the rate of direct transfer between opposing moments is directly determined by this coupling. Given the high sensitivity of RKKY to the conduction electrons, our results offer a useful approach for fine tuning the speed of magnetic devices.

[Overactive bladder pathogenetic features and choice of drug therapy].

The information about the founders of studies of the bladder function in our country, the features of the nervous and humoral regulation of the lower urinary tract activity, the cholinergic and adrenergic effects of mediators are presented in the article in the form of a clinical lecture. The pathogenetic features of detrusor dysfunction in overactive bladder and the principles of choosing drug therapy are described. Special attention is paid to the comparative characteristics of modern M-anticholinergics.

[A decrease in male reproductive potential in Russia: causes, diagnosis, possibilities for correction].

The causes, some pathogenetic mechanisms and possibilities for correcting the decrease in male reproductive potential in Russia are discussed in the lecture. Particular attention is paid to oxidative stress as one of the main causes for subfertility and male infertility, as well as the role of trace elements (zinc, selenium) and antioxidants (vitamins A, E and C) in the pathogenesis of male infertility and opportunities for the correction of fertility issues. Some aspects of COVID-19 influence on the problems of reproductive medicine, andrology and urology are highlighted.

[Combination of 1-blockers and phosphodiesterase type 5 inhibitor in patients with benign prostatic hyperplasia and erectile dysfunction: results of observatory prospective multicenter study].

AIM: To evaluate the efficacy and safety of combination therapy with 1-blocker and phosphodiesterase type 5 inhibitor (PDE5) in patients with benign prostatic hyperplasia (BPH) and erectile dysfunction (ED). MATERIALS AND METHODS: The observational multicenter program involving 18 medical institutions in Moscow included 315 men aged 40-65 years with BPH and ED. The inclusion criteria were a total IPSS score more than 8 points, QoL score of more than 3 points and clinical manifestations of ED ( less or equal 20 points on the IIEF-5 score). All patients received combined pharmacotherapy with Alfuprost MP 10 mg/day and Viatail 50 mg/day (if necessary, the dose was increased to 100 mg/day) for 3 months. RESULTS: The combination therapy showed a high clinical efficiency and a favorable safety profile. Lower urinary tract symptoms improved by more than 60%, QoL increased by 64% and erectile function improved in more than 80% of patients. At the end of treatment, the average patient satisfaction score on the Likert scale was 4.2 (high and very high satisfaction), while doctors satisfaction with the clinical response of patients to the treatment was 4.35 points, which also corresponds to high and very high efficacy of therapy. CONCLUSION: Combination of Alfuprost MP 10 mg/day and Viatail 50 mg/day (100 mg, if necessary) can be considered as one of the best options for non-surgical treatment of patients with BPH and ED.

[The effectiveness of local application of vancomycin powder in the prevention of surgical site infections in spine surgery: a meta-analysis]. / Effektivnost' lokal'nogo primeneniya poroshka vankomitsina v profilaktike infektsii oblasti khirurgicheskogo vmeshatel'stva v spinal'noi khirurgii: metaanaliz.

OBJECTIVE: To perform a meta-analysis of studies examining the effectiveness of the local application of vancomycin powder for the prophylaxis of surgical site infections (SSIs) in spine surgery. MATERIAL AND METHODS: Retrospective cohort studies and prospective randomized clinical trials were searched for in the Pubmed, EMBASE, Cochrane Library and eLibrary databases published from 2008 to December 2018. For the resulting variables, the odds ratio and 95% confidence interval were calculated using random and fixed effects models. Estimation of the degree of heterogeneity is estimated using the coefficient I2. Statistically significant differences were considered differences p<0.05. RESULTS: The meta-analysis included 28 clinical studies that included the results of the local application of vancomycin powder in 17,469 patients after performing various spinal surgical interventions. Two publications had a prospective, randomized, controlled study design. Topical application of vancomycin powder reduces the incidence of SSIs after spine surgery (p<0.0001). The use of vancomycin powder reduces the incidence of SSIs in patients operated on with stabilizing implants (p=0.004). On the other hand, the topical application of vancomycin powder did not affect the prevalence of SSIs in respondents who were operated on without the use of stabilizing implants (p=0.12) or due to deformities of the spine (p=0.06). CONCLUSION: Topical application of vancomycin powder is highly effective in preventing the development of SSIs in patients after spinal surgical interventions.

[Personalized brain revascularization: computer modeling of the reconstruction zone for carotid endarterectomy]. / Personifitsirovannaya revaskulyarizatsiya golovnogo mozga: metod komp'yuternogo modelirovaniya zony rekonstruktsii dlya provedeniya karotidnoi endarterektomii.

OBJECTIVE: To develop a technique of computer modeling of hemodynamics before conventional CEE. MATERIAL AND METHODS: Classical CEE is performed according to conventional patch technique. Duplex parameters of stenosis and blood flow velocity in the carotid arteries were analyzed by using of a linear transducer 7-7.5 MG (Acuson 128XP scanner, Acuson, USA). Multispiral computed tomography with angiography and subsequent processing of data using the Clear canvas software were performed to visualize the main geometric characteristics of the carotid arteries and features of atherosclerotic plaque. RESULTS: Blood flow hemodynamics is essential in the occurrence of postoperative restenosis. Therefore, computer simulation of blood flow using CFD (Computational Fluid Dynamics) methods based on particular patient's data makes it possible to assess localization of zones with high risk of restenosis. CFD approach implies construction of blood flow parameters at absolutely every point of the vessel considering geometric shape of the vessel and flow characteristics at the entrance and exit from the vessel. Pressure curves at the inlet and outlet are constructed using blood flow velocity curves. Pressure curves are subsequently used in the CFD model. The result of blood flow CFD modeling is non-stationary three-dimensional fields of pressure and velocity in the investigated area. Visual analysis of blood flow dynamics in these fields makes it possible to judge possible problem areas along the blood flow and on the inner wall of the vessel. DISCUSSION: Patch technique of classical CEE is characterized by great risk of parietal thrombosis and hyperproliferation of neointima that explains more frequent development of restenosis. Computer modeling is valuable to consider some important technical aspects in implementation of various surgical techniques for carotid artery reconstruction. CONCLUSION: This result demonstrates an importance of achieving the optimal ratio of the diameter of common, internal and external carotid arteries. Modification of patch based on computer simulation is required for these purposes.

Diseño de Sonrisa Digital / Digital Smile Desinge

Nowadays, a lot of people need in reconstruction of the teeth in connection with their loss. Before prosthetics or any other manipulations, a person wants to quickly see the aesthetic appearance of his future tooth. At the moment, many dentists use the option of verbal explanation to the patient, what will look like a smile or a front row of teeth after treatment, but the visual representation of the person remains aside. But now this can be achieved with the help of "Digital smile design", which shows the person the final result of the dentition. This technology has a number of advantages. Some of them are the rapid creation of a prototype model and high accuracy in the manufacture of work. Thanks to these technologies, communication between the specialist and the patient has been facilitated. The digital smile design has simplified the doctor's work process and reduced patient data processing time. From now on, achieving aesthetic results in the reconstruction of teeth for the dentist is not a problem.

Effect of Membrane Environment on the Ligand-Binding Properties of the Terminal Oxidase Cytochrome bd-I from Escherichia coli.

Cytochrome bd-I is a terminal oxidase of the Escherichia coli respiratory chain. This integral membrane protein contains three redox-active prosthetic groups (hemes b558, b595, and d) and couples the electron transfer from quinol to molecular oxygen to the generation of proton motive force, as one of its important physiological functions. The study was aimed at examining the effect of the membrane environment on the ligand-binding properties of cytochrome bd-I by absorption spectroscopy. The membrane environment was found to modulate the ligand-binding characteristics of the hemoprotein in both oxidized and reduced states. Absorption changes upon the addition of exogenous ligands, such as cyanide or carbon monoxide (CO), to the detergent-solubilized enzyme were much more significant and heterogeneous than those observed with the membrane-bound enzyme. In the native membranes, both cyanide and CO interacted mainly with heme d. An additional ligand-binding site (heme b558) appeared in the isolated enzyme, as was evidenced by more pronounced changes in the absorption in the Soret band. This additional reactivity could also be detected after treatment of E. coli membranes with a detergent. The observed effect did not result from the enzyme denaturation, since reconstitution of the isolated enzyme into azolectin liposomes restored the ligand-binding pattern close to that observed for the intact membranes.

[Results of analysis of the structural and functional state of the kidneys by the method of mathematical processing of contrast-enhancing MD-CT data in patients with urolithiasis].

INTRODUCTION: and Objectives: to date there have been several hypotheses on the causes of kidney stone formation. Compromised intrarenal blood flow might play one of major roles in stone formation. Advances in software and 3D technologies have unveiled the nature of contrast medium flow in the intrarenal structures. Mathematical analysis and 3D rendering of computed tomography (CT) scans was utilized for inrarenal contrast medium flow assessment in patients with stone kidney disease. This study aimed at assessing split glomerular filtration rate (sGFR) in patients at the initial stage of stone kidney disease (SKD). sGFR was measured by means of mathematical analysis of 3D rendering abdominal contrast enhanced CT scans. As well as that, possible correlations between irregular inrarenal contrast medium flow and causes of stone formation were considered. MATERIALS AND METHODS: 23 patients of both sexes with stone kidney disease (SKD) were recruited. They underwent US/Dopler investigation of the kidneys and the bladder, plain X-ray, histopathological evaluation of the tissues (those patients who were operated on), spectroscopic analysis of the stone(s). Mathematical analysis of 3D rendering of CT scans was utilized for sGFR assessment (sGFR reference value: 0,55% of contrast medium per second). Inclusion criteria are as follows: 1) newly diagnosed SKD; 2) stone size less than 1,5-2,0 cm 3) stones that do not block urine flow 4) non-operated young patients; 5) patients free of comorbidities. Inclusion criteria were set to mitigate the effects of other factors that might influence on intrarenal blood flow and conduct the study per se. RESULTS: Mathematical analysis of 3D rendering of CT scans allowed to elucidate changes in sGFR in 22 (95,6%) patients out of 23. HypErfiltration (hyperF) was detected in 10 (43,5%) patients, hypOfiltration (hypoF) was detected in 11(47,8%) patients. sGFR values were statistically significantly different in these groups both on the left (p=0,000142) and on the right (p=0,00068). No significant gender differences were observed (hypoF group aged 25-67 years with the mean age of 43,5 years; hyperF group aged 17-57 years with the mean age of 39 years (p=0,563). Ultrasound Doppler renal resistive index in renal arteries was within the normal range in both groups with no statistically significant difference between the groups. However, 1 patient demonstrated no sGFR changes. Another patient had hyporfiltration on the left (0,48%) and hyperfiltration on the right (0,62%) Conclusions: sGFR alterations (hypo- or hyperfiltration) were detected in the majority of the patients with SKD (95,6%). This in turn might be suggestive of compromised intrarenal blood flow. Further studies are needed to elucidate the optimal management of these patients.

[The features of course of chronic abacterial prostatitis with inflammatory compoment in men of the first period of mature age depending on the somatotype. Part 2: laboratory and imaging characteristics].

AIM: to study the course of chronic abacterial prostatitis with the inflammatory component (CAPIC) depending on the somatotype in men of the first period of mature age taking complex treatment with a use of local and systemic ozone therapy. MATERIALS AND METHODS: A total of 306 men of asthenic, normostenic and pyknic somatotypes with CAPIC were followed-up. Along with standard therapy, all patients received systemic and local ozone therapy. Clinical, laboratory and imaging characteristics were recorded before and after treatment. In addition, hemodynamic parameters in the prostate, prostatic part of the urethra and skin projection of the prostate were evaluated. RESULTS: In patients with pyknic somatotype (from 34.12+/-0.51 cm3 to 29.08+/-0.64 cm3) the most significant reduction in prostate size during the treatment with CAPIC was observed, while the improvement of microcirculation parameters were seen in patients with asthenic somatotype. Changes in the microcirculation in the mucous membrane of the prostatic part of the urethra and skin projection of the prostate during the treatment of CAPIC are somatotype-dependent. The highest values of tissue perfusion were found in patients of the normostenic somatotype, while pyknic patients had the smallest values. Along with somatotyping, this allows to use in clinical practice the abovementioned methods for early diagnosis and subsequent monitoring of the effectiveness of CAPIC therapy.

Features of Organization and Mechanism of Catalysis of Two Families of Terminal Oxidases: Heme-Copper and bd-Type.

Terminal oxidases of aerobic respiratory chains catalyze the transfer of electrons from the respiratory substrate, cytochrome c or quinol, to O2 with the formation of two H2O molecules. There are two known families of these membrane oxidoreductases: heme-copper oxidase superfamily and bd-type oxidase family (cytochromes bd) found in prokaryotes only. The redox reaction catalyzed by these enzymes is coupled to the generation of proton motive force used by the cell to synthesize ATP and to perform other useful work. Due to the presence of the proton pump, heme-copper oxidases create the membrane potential with a greater energy efficiency than cytochromes bd. The latter, however, play an important physiological role that enables bacteria, including pathogenic ones, to survive and reproduce under adverse environmental conditions. This review discusses the features of organization and molecular mechanisms of functioning of terminal oxidases from these two families in the light of recent experimental data.

[Computer-assisted simulation of haemodynamic parameters of carotid artery bifurcation after carotid endarterectomy]. / Komp'iuternoe modelirovanie gemodinamicheskikh pokazatelei v bifurkatsii sonnykh arterii posle karotidnoi éndarteréktomii.

Computer-aided simulation appropriately using the method of computational fluid dynamics (CFD) makes it possible to determine the elevated-risk zones of most probable formation of restenosis. The main idea of the method described in our article consists in a possibility of creating by the model of the geometrical shape of the vessel and characteristics of the flow at inlets and outlets the parameters of flow in each point of a vessel. The curves of velocity are used to create the curves of pressure at inlets and outlets, which are used in a CFD model. The resulting from CFD simulation of blood flow are nonstationary three-dimensional fields of pressure and velocity in the area under study. Visual examination of the dynamics of these fields makes it possible to judge about possible problem zones inside the area of flow and on the internal wall of the vessel. This article also presents a clinical case report illustrating the use of this technique.

[Local administration of vancomycin powder in posterior lumbar fusion surgery]. / Éffektivnost' mestnogo primeneniia vankomitsina pri zadnikh dekompressivno-stabiliziruiushchikh operativnykh vmeshatel'stvakh na poiasnichno-kresttsovom otdele pozvonochnika.

AIM: To evaluate an efficacy of local administration of vancomycin powder in posterior lumbar fusion surgery for prevention of local infection. MATERIAL AND METHODS: The study included 214 patients. All patients were divided into 2 groups: I group (control) and II (experimental). Patients of the first group underwent conventional antibiotic prophylaxis of wound infections, in group II traditional antibiotic prophylaxis was supplemented by local administration of vancomycin powder 1 g prior to wound closure. RESULTS: There were 12 cases of wound infection in group I and 5 cases in group II. There were significant differences in overall incidence of wound infection and wound infections caused by S. aureus (p=0.035; p=0.044, respectively). Significant risk factors of local infection were determined in group II: obesity, diabetes mellitus, arterial hypertension, coronary artery disease, length of hospital-stay and previous lumbosacral spinal surgery. Multivariate analysis revealed following risk factors of wound infection: diabetes mellitus, arterial hypertension, coronary artery disease, the number of involved spinal segments and previous lumbosacral spinal surgery. CONCLUSION: Local application of vancomycin powder in posterior lumbar fusion surgery significantly reduces the incidence of wound infection.

Role of tetrahedrally coordinated dopants in palladium hydrides on their superconductivity and inverse isotope effect.

Absorption of hydrogen by palladium causes PdH to become superconducting below [Formula: see text]. Due to the presence of one octapore and two tetrapores per each Pd atom, it is believed that [Formula: see text] of PdH[Formula: see text] should increase further. Here, using ab initio calculation we show that (i) H placed in tetrapores of PdH[Formula: see text] induces a wide optical gap in the phonon density of states, which significantly reduces the electron-phonon coupling, and that (ii) the energetically preferable octapores filled by H enable the 9 K superconductivity only. This scenario may close a long-standing problem of the high-[Formula: see text] palladium hydrides. Moreover, simulating the pore population by H and D, within ab initio molecular dynamics, we are able to explain the inverse isotope effect in the framework of the Bardeen-Cooper-Schrieffer theory.

[A new method of evaluation of split renal function based on contrast-enhanced multislice spiral computed tomography].

INTRODUCTION: Traditionally, evaluation of the split renal function is performed using nephroscintigraphy. However, as shown in several studies, there might be quite significant inaccuracy in the interpretation of dynamic nephroscintigraphy results. But due to the lack of alternative methods for evaluation of split renal function, nephroscintigraphy remains the method of choice. AIM: To investigate the feasibility of digital analysis of contrast-enhanced MSCT imaging for evaluation of the split renal function. MATERIALS AND METHODS: This is a prospective study conducted at the R.M. Fronshteyn Clinic of Urology from November 2015 to February 2017. The study comprised 31 patients with urolithiasis (n=7), hydronephrosis (n=9), kidney cancer (n=14) and urinary bladder tumor (n=1). During the preoperative period, the patients underwent contrast-enhanced MSCT, 3D-reconstruction, and digital analysis. The obtained data were compared with the results of dynamic nephroscintigraphy. RESULTS: Contrast-enhanced MSCT findings were not inferior to data obtained with dynamic nephroscintigraphy regarding information content (p<0.004). CONCLUSIONS: The new method of digital processing of three-dimensional contrast-enhanced MSCT allows for concomitant assessment of both the anatomical features of the kidney and renal function that may help to improve the accuracy of surgical planning to choose the optimal extension of the intervention.