72 results on '"Bykov AV"'
Search Results
2. The Role of the Vascular Factor in the Reorganization of Water Metabolism in Denervated Liver after Bacterial Endotoxin Poisoning
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Tsibulevskiĭ AIu, Bykov Av, Gadziev KhK, Sergeev Ai, Dubovaia Tk, and Shchegolev Ai
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medicine.medical_specialty ,Lipopolysaccharide ,medicine.medical_treatment ,Vagotomy ,Vascular factor ,General Biochemistry, Genetics and Molecular Biology ,Microcirculation ,chemistry.chemical_compound ,Endocrinology ,Sinusoid ,chemistry ,Biochemistry ,Cytoplasm ,Internal medicine ,medicine ,Water metabolism ,Bacterial endotoxin ,sense organs ,General Agricultural and Biological Sciences - Abstract
Intoxication with bacterial lipopolysaccharide (endotoxin) is accompanied by considerable rearrangements in the systems of blood microcirculation and water metabolism of the liver. These rearrangements are manifested as increased sinusoid area, changed total area of the cytoplasm and nuclei as well as the nucleocytoplasmic ratio in hepatocytes, increased content of total water in the organ, and changed magnetic relaxation properties (spin-lattice and spin-spin relaxation times). Preliminary parasympathetic denervation of the liver (vagotomy) changes the pattern of the organ response to bacterial endotoxin poisoning as indicated by the kinetics of studied morphological and biophysical parameters.
- Published
- 2005
3. PCV52 ECONOMIC ANALYSIS OF THE USE OF CLOPIDOGREL IN PATIENTS WITH ACUTE CORONARY SYNDROME WITHOUT STSEGMENT ELEVATION (ACS) FROM THE RUSSIAN HEALTH CARE SYSTEM PERSPECTIVE
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Belousov, YB, primary, Lazebnik, LB, additional, Bykov, AV, additional, Nguyen, T, additional, and Spiesser, J, additional
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- 2003
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4. PNP13 QUALITY OF LIFE (QOL) AND PHARMACOECONOMICAL ASPECTS IN PATIENTS WITH SYMPTOMATIC LOCALIZATION-RELATED EPILEPSIES (SLE) IN MOSCOW
- Author
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Guekht, AB, primary, Gusev, EI, additional, Belousov, JB, additional, Bykov, AV, additional, Dzugaeva, FK, additional, Milchakova, LE, additional, and Mitrokhina, TV, additional
- Published
- 2002
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5. Nano selenium in broiler feeding: physiological roles and nutritional effects.
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Hosseintabar-Ghasemabad B, Kvan OV, Sheida EV, Bykov AV, Zigo F, Seidavi A, Elghandour MMMY, Cipriano-Salazar M, Lackner M, and Salem AZM
- Abstract
Using nanotechnology, while improving the health of broiler chickens, it is possible to control and reduce the conflict of minerals in the intestines, and toxicity of and pollution by these elements. It could be shown that the antioxidant and immune modulation effects of nano selenium are significantly superior compared to other sources of selenium. In addition, improving the quality of meat products with the use of nano selenium has promising results in the future perspective of quality improvement and food safety. Nutrition of permitted and optimal levels is very important in the consumption of nano selenium form and as it can have significant beneficial functional and health effects, in case of errors in the selected levels and doses, irreparable side effects and adverse results can occur. In this review report, an attempt has been made to introduce the position and importance of selenium and the approach of smart consumption of its nano form in the nutrition of broiler chickens. The novelty of using nanotechnology in feeding broiler chickens can be a unique opportunity to improve the bioavailability of important and rare elements such as selenium., (© 2024. The Author(s).)
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- 2024
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6. Magnetic Nanoparticle Support with an Ultra-Thin Chitosan Layer Preserves the Catalytic Activity of the Immobilized Glucose Oxidase.
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Tikhonov BB, Lisichkin DR, Sulman AM, Sidorov AI, Bykov AV, Lugovoy YV, Karpenkov AY, Bronstein LM, and Matveeva VG
- Abstract
Here, we developed magnetically recoverable biocatalysts based on magnetite nanoparticles coated with an ultra-thin layer (about 0.9 nm) of chitosan (CS) ionically cross-linked by sodium tripolyphosphate (TPP). Excessive CS amounts were removed by multiple washings combined with magnetic separation. Glucose oxidase (GOx) was attached to the magnetic support via the interaction with N-hydroxysuccinimide (NHS) in the presence of carbodiimide (EDC) leading to a covalent amide bond. These steps result in the formation of the biocatalyst for D-glucose oxidation to D-gluconic acid to be used in the preparation of pharmaceuticals due to the benign character of the biocatalyst components. To choose the catalyst with the best catalytic performance, the amounts of CS, TPP, NHS, EDC, and GOx were varied. The optimal biocatalyst allowed for 100% relative catalytic activity. The immobilization of GOx and the magnetic character of the support prevents GOx and biocatalyst loss and allows for repeated use., Competing Interests: The authors declare no conflicts of interest.
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- 2024
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7. Highly Selective CO 2 Hydrogenation to Methanol over Complex In/Co Catalysts: Effect of Polymer Frame.
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Sorokina SA, Kuchkina NV, Mikhailov SP, Mikhalchenko AV, Bykov AV, Doluda VY, Bronstein LM, and Shifrina ZB
- Abstract
The growing demand for new energy sources governs the intensive research into CO
2 hydrogenation to methanol, a valuable liquid fuel. Recently, indium-based catalysts have shown promise in this reaction, but they are plagued by shortcomings such as structural instability during the reaction and low selectivity. Here, we report a new strategy of controlling the selectivity and stability of bimetallic magnetically recoverable indium-based catalysts deposited onto a solid support. This was accomplished by the introduction of a structural promoter: a branched pyridylphenylene polymer (PPP). The selectivity of methanol formation for this catalyst reached 98.5%, while in the absence of PPP, the catalysts produced a large amount of methane, and the selectivity was about 70.2%. The methanol production rate was higher by a factor of twelve compared to that of a commercial Cu-based catalyst. Along with tuning selectivity, PPP allowed the catalyst to maintain a high stability, enhancing the CO2 sorption capacity and the protection of In against sintering and over-reduction. A careful evaluation of the structure-activity relationships allowed us to balance the catalyst composition with a high level of structural control, providing synergy between the support, magnetic constituent, catalytic species, and the stabilizing polymer layer. We also uncovered the role of each component in the ultimate methanol activity and selectivity.- Published
- 2023
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8. Should we encourage the use of robotic technologies in complicated diverticulitis? Results of systematic review and meta-analysis.
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Panin SI, Nechay TV, Sazhin AV, Tyagunov AE, Shcherbakov NA, Bykov AV, Melnikov-Makarchuk KY, Yuldashev AG, and Kuznetsov AA
- Abstract
Introduction: Complicated diverticulitis is a common abdominal emergency that often requires a surgical intervention. The systematic review and meta-analysis below compare the benefits and harms of robotic vs. laparoscopic surgery in patients with complicated colonic diverticular disease. Methods: The following databases were searched before 1 March 2023: Cochrane Library, PubMed, Embase, CINAHL, and ClinicalTrials.gov. The internal validity of the selected non-randomized studies was assessed using the ROBINS-I tool. The meta-analysis and trial sequential analysis were performed using RevMan 5.4 (Cochrane Collaboration, London, United Kingdom) and Copenhagen Trial Unit Trial Sequential Analysis (TSA) software (Copenhagen Trial Unit, Center for Clinical Intervention Research, Rigshospitalet, Copenhagen, Denmark), respectively. Results: We found no relevant randomized controlled trials in the searched databases. Therefore, we analyzed 5 non-randomized studies with satisfactory internal validity and similar designs comprising a total of 442 patients (184 (41.6%) robotic and 258 (58.4%) laparoscopic interventions). The analysis revealed that robotic surgery for complicated diverticulitis (CD) took longer than laparoscopy (MD = 42 min; 95% CI: [-16, 101]). No statistically significant differences were detected between the groups regarding intraoperative blood loss (MD = -9 mL; 95% CI: [-26, 8]) and the rate of conversion to open surgery (2.17% or 4/184 for robotic surgery vs. 6.59% or 17/258 for laparoscopy; RR = 0.63; 95% CI: [0.10, 4.00]). The type of surgery did not affect the length of in-hospital stay (MD = 0.18; 95% CI: [-0.60, 0.97]) or the rate of postoperative complications (14.1% or 26/184 for robotic surgery vs. 19.8% or 51/258 for laparoscopy; RR = 0.81; 95% CI: [0.52, 1.26]). No deaths were reported in either group. Discussion: The meta-analysis suggests that robotic surgery is an appropriate option for managing complicated diverticulitis. It is associated with a trend toward a lower rate of conversion to open surgery and fewer postoperative complications; however, this trend does not reach the level of statistical significance. Since no high quality RCTs were available, this meta-analysis isnot able to provide reliable conclusion, but only a remarkable lack of proper evidence supporting robotic technology. The need for further evidence-based trials is important., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Panin, Nechay, Sazhin, Tyagunov, Shcherbakov, Bykov, Melnikov-Makarchuk, Yuldashev and Kuznetsov.)
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- 2023
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9. Naphthalene-Based Polymers as Catalytic Supports for Suzuki Cross-Coupling.
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Bakhvalova ES, Bykov AV, Markova ME, Lugovoy YV, Sidorov AI, Molchanov VP, Sulman MG, Kiwi-Minsker L, and Nikoshvili LZ
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- Solvents, Water, Catalysis, Naphthalenes, Polymers, Palladium
- Abstract
In this work, for the first time, naphthalene (NA)-based polymers were synthesized by one-stage Friedel-Crafts crosslinking. The influence of NA functionalization by -OH, -SO
3 H, and -NO2 groups on the polymers' porosity and distribution of the catalytically active phase (Pd) was studied. Synthesized catalytic systems containing 1 wt.% of Pd either in the form of Pd(II) species or Pd(0) nanoparticles supported on NA-based polymers were tested in a model reaction of Suzuki cross-coupling between 4-bromoanisole and phenylboronic acid under mild reaction conditions (60 °C, ethanol-water mixture as a solvent). These novel catalysts demonstrated high efficiency with more than 95% of 4-bromoanisole conversion and high selectivity (>97%) for the target 4-methoxybiphenyl.- Published
- 2023
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10. Synthesis, Crystal, and Electronic Structure of (HpipeH 2 ) 2 [Sb 2 I 10 ](I 2 ), with I 2 Molecules Linking Sb 2 X 10 Dimers into a Polymeric Anion: A Strategy for Optimizing a Hybrid Compound's Band Gap.
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Bykov AV, Shestimerova TA, Bykov MA, Osminkina LA, Kuznetsov AN, Gontcharenko VE, and Shevelkov AV
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- Anions, Serogroup, Polymers, Electronics
- Abstract
In searching for a tool for optimizing the band gap of a hybrid compound capable of serving as a light-harvesting material in lead-free photovoltaics, we synthesized a new polyiodoantimonate (HpipeH
2 )2 [Sb2 I10 ](I2 ) and analyzed its crystal and electronic structure by application of X-ray crystal structure analysis, Raman and diffuse reflectance spectroscopies, and quantum chemical calculations. It was demonstrated that I2 molecules link Sb2 I10 edge-sharing octahedra into zig-zag chains, whereas the organic cations link inorganic anionic chains into a 3D structure featuring a complex pattern of covalent bonds and non-covalent interactions. Overall, these features provide the background for forming the electronic structure with a narrow band gap of 1.41 eV, therefore being a versatile tool for optimizing the band gap of a potential light-harvesting hybrid compound.- Published
- 2023
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11. [Clinical and economic aspects of laparoscopic surgery for acute cholecystitis in delayed presentation].
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Panin SI, Akinchits AN, Bykov AV, Chepurina NG, Kushniruk NE, Durmyshev DA, Us OA, and Suvorov VA
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- Male, Humans, Female, Adult, Middle Aged, Aged, Prospective Studies, Time Factors, Length of Stay, Treatment Outcome, Cholecystitis, Acute diagnosis, Cholecystitis, Acute surgery, Cholecystectomy, Laparoscopic adverse effects, Cholecystectomy, Laparoscopic methods, Laparoscopy adverse effects
- Abstract
Objective: To study the clinical and economic features of laparoscopic surgery for acute cholecystitis in delayed presentation., Material and Methods: A prospective non-randomized study (2020-2021) included 101 patients (73.2% ( n =74) men and 26.8% ( n =27) women, mean age 58±14.9 years) with acute cholecystitis who underwent laparoscopic cholecystectomy. Cost-effectiveness analysis of laparoscopic cholecystectomy at various periods after clinical manifestation was performed., Results: Surgical treatment within 72 hours was performed in 15% ( n =16) of cases (group 1), within 4-10 days - in 57.5% ( n =58) (group 2), after 10 days - in 26.7% ( n =27) of patients (group 3). Overall incidence of postoperative complications was 2.9%, postoperative mortality - 1.9% (two patients died from widespread peritonitis). Surgery time was 70 [65-83], 85 [69-110] and 115 [80-125] min (H=15.55, p <0.001), hospital-stay - 6 [5-7], 9 [7-10] and 11 [7-14] days, respectively (H=21.86, p <0.001). Cost of direct (medical and non-medical) treatment amounted to 29484 [27 509-33 885], 41265 [34 306-48 301] and 50591 [37 069-62 483] rubles, respectively (H=29.71, p <0.001))., Conclusion: Delayed hospitalization and surgical treatment of acute cholecystitis after 72 hours are accompanied by higher treatment costs by 29% in the period up to 10 days and by 58% after 10 days. These results require further validation and adjustment in large samples.
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- 2023
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12. Ni Nanoparticles Stabilized by Hyperbranched Polymer: Does the Architecture of the Polymer Affect the Nanoparticle Characteristics and Their Performance in Catalysis?
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Sorokina SA, Kuchkina NV, Ezernitskaya MG, Bykov AV, Vasiliev AL, Efimov NN, and Shifrina ZB
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- Oxidation-Reduction, Catalysis, Microscopy, Electron, Scanning Transmission, Polymers, Nanoparticles chemistry
- Abstract
Heat-up and hot-injection methods were employed to synthesize Ni nanoparticles (NPs) with narrow size distribution in the presence of hyperbranched pyridylphenylene polymer (PPP) as a stabilizing agent. It was shown that depending on the synthetic method, Ni NPs were formed either in a cross-linked polymer network or stabilized by a soluble hyperbranched polymer. Ni NPs were characterized by a combination of transmission electron microscopy (TEM), scanning TEM, thermogravimetric analysis, powder X-ray diffraction, X-ray photoelectron spectroscopy, energy dispersive X-ray analysis, and magnetic measurements. The architecture of polymer support was found to significantly effect Ni NPs characteristics and behavior. The Ni NPs demonstrated a high catalytic activity in a model Suzuki-Miyaura cross-coupling reaction. No significant drop in activity was observed upon repeated use after magnetic separation in five consecutive catalytic cycles. We believe that hyperbranched PPP can serve as universal platform for the controllable synthesis of Ni NPs, acting as highly active and stable catalysts.
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- 2022
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13. Hybrid Pd-Nanoparticles within Polymeric Network in Selective Hydrogenation of Alkynols: Influence of Support Porosity.
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Nikoshvili LZ, Popov AY, Bykov AV, Sidorov AI, and Kiwi-Minsker L
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- Catalysis, Hydrogenation, Porosity, Nanoparticles, Palladium chemistry
- Abstract
This work is addressing the selective hydrogenation of alkynols over hybrid catalysts containing Pd-nanoparticles, within newly synthesized hyper-cross-linked polystyrenes (HPS). Alkynols containing C
5 , C10 , and C20 with a terminal triple bond, which are structural analogues or direct semi-products of fragrant substances and fat-soluble vitamins, have been studied. Selective hydrogenation was carried out in a batch mode (ambient hydrogen pressure, at 90 °C, in toluene solvent), using hybrid Pd catalysts with low metal content (less than 0.2 wt.%). The microporous and mesoporous HPS were both synthesized and used as supports in order to address the influence of porosity. Synthesized catalysts were shown to be active and selective: in the case of C5 , hydrogenation selectivity to the target product was more than 95%, at close to complete alkynol conversion. Mesoporous catalysts have shown some advantages in hydrogenation of long-chain alkynols.- Published
- 2022
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14. Ru@hyperbranched Polymer for Hydrogenation of Levulinic Acid to Gamma-Valerolactone: The Role of the Catalyst Support.
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Sorokina SA, Mikhailov SP, Kuchkina NV, Bykov AV, Vasiliev AL, Ezernitskaya MG, Golovin AL, Nikoshvili LZ, Sulman MG, and Shifrina ZB
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- Catalysis, Cellulose chemistry, Hydrogenation, Molecular Structure, Spectrum Analysis, Temperature, Lactones chemistry, Levulinic Acids chemistry, Polymers chemistry, Ruthenium chemistry
- Abstract
Hydrogenation of levulinic acid (LA) obtained from cellulose biomass is a promising path for production of γ-valerolactone (GVL)-a component of biofuel. In this work, we developed Ru nanoparticle containing nanocomposites based on hyperbranched pyridylphenylene polymer, serving as multiligand and stabilizing matrix. The functionalization of the nanocomposite with sulfuric acid significantly enhances the activity of the catalyst in the selective hydrogenation of LA to GVL and allows the reaction to proceed under mild reaction conditions (100 °C, 2 MPa of H
2 ) in water and low catalyst loading (0.016 mol.%) with a quantitative yield of GVL and selectivity up to 100%. The catalysts were successfully reused four times without a significant loss of activity. A comprehensive physicochemical characterization of the catalysts allowed us to assess structure-property relationships and to uncover an important role of the polymeric support in the efficient GVL synthesis.- Published
- 2022
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15. [Perforated peptic ulcer in patients with cancer: prediction of postoperative morbidity and mortality].
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Panin SI, Suvorov VA, Kovalenko NV, Bykov AV, Postolov MP, Linchenko AM, Kosivtsov OA, and Mikhin ES
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- Aged, Humans, Morbidity, Postoperative Period, Prognosis, Neoplasms complications, Neoplasms drug therapy, Neoplasms mortality, Peptic Ulcer Perforation complications, Peptic Ulcer Perforation mortality, Peptic Ulcer Perforation surgery
- Abstract
Objective: To analyze treatment outcomes and approaches to predicting the postoperative morbidity and mortality in patients with perforated ulcers and cancer., Material and Methods: A non-randomized trial included 194 patients. The first group enrolled 45 (23%) patients with perforated ulcers and concomitant cancer who underwent at the oncology center; the second group included 149 (77%) patients with perforated ulcers and no cancer who underwent surgery in general surgical hospitals. Organ-sparing procedures prevailed (40 (88.9%) and 138 (92.6%) cases, respectively). Resections were performed in 5 (11.1%) and 11 (7.4%) patients respectively. Analyzing the factors affecting treatment outcomes, we studied crude (COR) and adjusted (AOR) odds ratios. ROC-analysis was used to assess diagnostic significance of the models for prognosis of morbidity and mortality., Results: Length of hospital-stay was 10 (range 9-14) and 8 (range 7-9) days respectively. Postoperative complications (Clavien-Dindo grading system) occurred in 18 (40%) in 37 (24.8%) patients, respectively. According to multivariate analysis, predictors of complications in patients of the first group were treatment with NSAIDs/glucocorticoids and Charlson-Deyo index >3. Sensitivity of this model was 82.4%, specificity - 75.0%. Postoperative mortality was 15.6% ( n =7) and 7.4% ( n =11) respectively. According to multivariate analysis, predictors of mortality were age over 65 years and more than 5 chemotherapeutic courses. Sensitivity of the model was 85.7%, specificity - 97.4%., Conclusion: The stratified approach makes it possible to improve prediction of postoperative morbidity and mortality in patients with perforated ulcers.
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- 2022
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16. Development of a Fuzzy Diagnostic Model of Ischemic Disease of the Lower Limbs for Different Stages of Patient Management.
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Korenevskiy NA, Bykov AV, Al-Kasasbeh RT, Al-Smadi MM, Aikeyeva AA, Al-Jund M, Al-Kasasbeh ET, Rodionova SN, Ilyash M, and Shaqadan A
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- Humans, Ischemia diagnosis, Artificial Intelligence, Lower Extremity
- Abstract
Ischemic disease has severe impact on patients which makes accurate diagnosis vital for health protection. Improving the quality of prediction of patients with ischemic extremity disease by using hybrid fuzzy model allows for early and accurate prognosis of the development of the disease at various stages. The prediction of critical ischemia of lower extremity (CLI) at various disease stages is complex problem due to inter-related factors. We developed hybrid fuzzy decision rules to classify ischemic severity using clinical thinking (natural intelligence) with artificial intelligence, which allows achieving a new quality in solving complex systemic problems and is innovative. In this study mathematical model was developed to classify the risk level of CLI into: subcritical ischemia, favorable outcome, questionable outcome, and unfavorable outcome. The prognosis is made using such complex indicators as confidence that the patient will develop gangrene of the lower extremity (unfavorable outcome), complex coefficient of variability, and reversibility of the ischemic process. Model accuracy was calculated using representative control samples that showed high diagnostic accuracy and specificity characterizing the quality of prediction are 0.9 and higher, which makes it possible to recommend their use in medical practice.
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- 2022
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17. [Comparison of robot-assisted and conventional endoscopic surgeries in the Russian Federation. (A systematic review and meta-analysis)].
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Nechay TV, Panin SI, Sazhin AV, Bykov AV, Shcherbakov NA, Pegushina EA, Kuznetsov AA, Tyagunov AE, Melnikov-Makarchuk KY, and Yuldashev AG
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- Blood Loss, Surgical, Humans, Length of Stay, Operative Time, Postoperative Complications epidemiology, Postoperative Complications etiology, Postoperative Complications prevention & control, Treatment Outcome, Laparoscopy methods, Robotic Surgical Procedures adverse effects, Robotic Surgical Procedures methods, Robotics
- Abstract
Objective: Comparative assessment of immediate and long-term results of robot-assisted and conventional endoscopic technologies in the Russian Federation., Material and Methods: Searching for primary trials devoted to robot-assisted (RAE) and traditional video endoscopic (TVE) surgeries in the Russian Federation was carried out in the e-library and CENTRAL Cochrane databases. We used the recommendations of the Center for Expertise and Quality Control of Medical Care (2017, 2019) and the current version of the Cochrane Community Guidelines (2021). These guidelines define the features of meta-analysis of non-randomized comparative studies. Review Manager 5.4 software was used for statistical analysis., Results: We enrolled 26 Russian-language primary sources (3111 patients) including 1174 (38%) ones in the RAE group and 1937 (62%) patients in the TVE group. There were no randomized controlled trials in the Russian Federation, and all primary studies were non-randomized. We found no significant between-group differences in surgery time, incidence of intraoperative complications, intraoperative blood loss in thoracic surgery, urology and gynecology, conversion rate, postoperative hospital-stay, postoperative morbidity (in abdominal surgery, urology and gynecology), postoperative mortality. We observed slightly lower intraoperative blood loss for RAE in abdominal surgery and lower incidence of postoperative complications in robot-assisted thoracic surgery. These results can be compromised by methodological quality of comparative studies, significant heterogeneity and systematic errors., Conclusion: Currently, we cannot confirm the benefits of robot-assisted technologies, since this approach does not worsen or improve treatment outcomes. Further high-quality studies are needed.
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- 2022
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18. Mono- and Bimetallic Nanoparticles Stabilized by an Aromatic Polymeric Network for a Suzuki Cross-Coupling Reaction.
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Nikoshvili LZ, Shkerina KN, Bykov AV, Sidorov AI, Vasiliev AL, Sulman MG, and Kiwi-Minsker L
- Abstract
This work addresses the Suzuki cross-coupling between 4-bromoanisole (BrAn) and phenylboronic acid (PBA) in an environmentally benign ethanol-water solvent catalysed by mono- (Pd) and bimetallic (PdAu, PdCu, PdZn) nanoparticles (NPs) stabilised within hyper-cross-linked polystyrene (HPS) bearing tertiary amino groups. Small Pd NPs of about 2 nm in diameters were formed and stabilized by HPS independently in the presence of other metals. High catalytic activity and complete conversion of BrAn was attained at low Pd loading. Introduction of Zn to the catalyst composition resulted in the formation of Pd/Zn/ZnO NPs, which demonstrated nearly double activity as compared to Pd/HPS. Bimetallic core-shell PdAu/HPS samples were 3-fold more active as compared to Pd/HPS. Both Pd/HPS and PdAu/HPS samples revealed promising stability confirmed by catalyst recycling in repeated reaction runs.
- Published
- 2021
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19. Magnetically Recoverable Nanoparticulate Catalysts for Cross-Coupling Reactions: The Dendritic Support Influences the Catalytic Performance.
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Kuchkina NV, Sorokina SA, Bykov AV, Sulman MG, Bronstein LM, and Shifrina ZB
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Carbon-carbon cross-coupling reactions are among the most important synthetic tools for the preparation of pharmaceuticals and bioactive compounds. However, these reactions are normally carried out using copper, phosphines, and/or amines, which are poisonous for pharmaceuticals. The use of nanocomposite catalysts holds promise for facilitating these reactions and making them more environmentally friendly. In the present work, the PEGylated (PEG stands for poly(ethylene glycol) pyridylphenylene dendrons immobilized on silica loaded with magnetic nanoparticles have been successfully employed for the stabilization of Pd
2+ complexes and Pd nanoparticles. The catalyst developed showed excellent catalytic activity in copper-free Sonogashira and Heck cross-coupling reactions. The reactions proceeded smoothly in green solvents at low palladium loading, resulting in high yields of cross-coupling products (from 80% to 97%) within short reaction times. The presence of magnetic nanoparticles allows easy magnetic separation for repeated use without a noticeable decrease of catalytic activity due to the strong stabilization of Pd species by rigid and bulky dendritic ligands. The PEG dendron periphery makes the catalyst hydrophilic and better suited for green solvents. The minor drop in activity upon the catalyst reuse is explained by the formation of Pd nanoparticles from the Pd2+ species during the catalytic reaction. The magnetic separation and reuse of the nanocomposite catalyst reduces the cost of target products as well as energy and material consumption and diminishes residual contamination by the catalyst. These factors as well as the absence of copper in the catalyst makeup pave the way for future applications of such catalysts in cross-coupling reactions.- Published
- 2021
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20. Hyper-Cross-Linked Polystyrene as a Stabilizing Medium for Small Metal Clusters.
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Bykov AV, Demidenko GN, Nikoshvili LZ, and Kiwi-Minsker L
- Abstract
Among different polymers nanostructured cross-linked aromatics have the greatest potential as catalytic supports due to their exceptional thermal and chemical stability and preservation of the active phase morphology. This work studies the ability of hyper-cross-linked polystyrene (HPS) to stabilize small Pd
n and Ptn ( n = 4 or 9) clusters. Unrestricted DFT calculations were carried out for benzene (BZ) adsorption at the BP level of theory using triple-zeta basis sets. The adsorption of BZ rings (stepwise from one to four) was found to result in noticeable gain in energy and stabilization of resulting adsorption complexes. Moreover, the interaction of metal clusters with HPS micropores was also addressed. For the first time, the incorporation of small clusters in the HPS structure was shown to influences its geometry resulting in the stabilization of polymer due to its partial relaxation.- Published
- 2021
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21. Noble Metal Nanoparticles Stabilized by Hyper-Cross-Linked Polystyrene as Effective Catalysts in Hydrogenation of Arenes.
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Bakhvalova ES, Pinyukova AO, Mikheev AV, Demidenko GN, Sulman MG, Bykov AV, Nikoshvili LZ, and Kiwi-Minsker L
- Abstract
This work is addressing the arenes' hydrogenation-the processes of high importance for petrochemical, chemical and pharmaceutical industries. Noble metal (Pd, Pt, Ru) nanoparticles (NPs) stabilized in hyper-cross-linked polystyrene (HPS) were shown to be active and selective catalysts in hydrogenation of a wide range of arenes (monocyclic, condensed, substituted, etc.) in a batch mode. HPS effectively stabilized metal NPs during hydrogenation in different medium (water, organic solvents) and allowed multiple catalyst reuses.
- Published
- 2021
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22. [Open and laparoscopic surgery via minimally invasive approach in the treatment of perforated ulcer: a systematic review and metaanalysis].
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Panin SI, Beburishvili AG, Prudkov MI, Sovtsov SA, Timerbulatov VM, Bykov AV, Abdullaev EG, Khasanov AG, Nishnevich EV, and Fedorov AV
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- Humans, Length of Stay, Minimally Invasive Surgical Procedures adverse effects, Minimally Invasive Surgical Procedures methods, Treatment Outcome, Laparoscopy adverse effects, Laparoscopy methods, Laparotomy adverse effects, Laparotomy methods, Peptic Ulcer Perforation diagnosis, Peptic Ulcer Perforation surgery
- Abstract
Objective: Systematic review and metaanalysis of the effectiveness of open and minimally invasive laparoscopic suturing of perforated peptic ulcer., Material and Methods: Searching for Russian and English language reports included Scientific Electronic Library, Cochrane Collaboration Library and PubMed databases. We have analyzed contents of specialized journals, reviews and their references. Unpublished data were obtained via communication with chiefs of national surgical hospitals. RevMan 5.3 software was used for metaanalysis., Results: We found no international randomized trials in available literature. Metaanalysis was based on national non-randomized studies. Total sample was 1177 cases. Laparoscopic minimally invasive surgery was performed in 43% of cases ( n =503), open suturing - in 57% ( n =674) of patients. Choice of these procedures is not currently not standardized. Minimally invasive procedures are shorter in time (mean difference -8.02, 95% CI -11.26 - -4.77, p <0.00001) and ensure less hospital-stay (mean difference -1.93, 95% CI -2.97 - -0.88, p =0.0003). Complications were less common (OR 0.14, 95% CI 0.07-0.27, p <0.00001) after minimally invasive operations (2.4%, 12/503) compared to laparotomy (11.4%, 77/674). Incidence of suture failure was similar (OR 0.4, 95% CI 0.1-1.6, p =0.2) (0.4% (2/503) vs. 0.7% (5/674)). Postoperative mortality was higher (OR 0.14, 95% CI 0.05-0.37, p <0.0001) after laparotomy (8%, 54/674) compared to laparoscopy (0.8%, 4/503)., Conclusion: A metaanalysis indicates the advantage of laparoscopy-assisted suturing of perforated ulcer via minimally invasive approach over laparotomy. The absence of a standardized approach in choosing of minimally invasive laparotomy and conventional approach is a limitation of these results.
- Published
- 2021
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23. Fuzzy Models of Choice of Prevention Schemes for the Occurrence and Development of Gangrene of the Lower Extremities.
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Korenevskiy NA, Bykov AV, Al-Kasasbeh RT, Aikeyeva AA, Alshamasin MS, Rodionova SN, Ilyash M, Parkhomenko SA, Al-Smadi MM, and Al-Jundi M
- Subjects
- Amputation, Surgical, Fuzzy Logic, Humans, Recurrence, Gangrene prevention & control, Gangrene surgery, Lower Extremity
- Abstract
The study focuses on the choice of prevention schemes of the appearance and recurrence of gangrene of the lower extremities, depending on any of the degrees of confidence that the patient will have gangrene or will experience its relapse. The degree of confidence is determined using the fuzzy logic of decision making on the relevant membership functions. For each of the selected classes, an appropriate prevention scheme has been developed, the effectiveness of which was tested using the theory of measuring latent variables and the synthesis of mathematical models of their choice depending on the degree of risk of the occurrence and recurrence of lower extremities gangrene. Model statistical tests showed that compared with traditional prevention schemes the use of the proposed models can increase the rate of positive results in the absence of lower extremities gangrene and reduce the possibility of relapse (recurrent changes by 42%, risk of amputation by 35%).
- Published
- 2021
- Full Text
- View/download PDF
24. Selective Hydrogenation of Biomass-Derived Furfural: Enhanced Catalytic Performance of Pd-Cu Alloy Nanoparticles in Porous Polymer.
- Author
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Salnikova KE, Larichev YV, Sulman EM, Bykov AV, Sidorov AI, Demidenko GN, Sulman MG, Bronstein LM, and Matveeva VG
- Abstract
Here, the development of a new catalyst is reported for the selective furfural (FF) hydrogenation to furfuryl alcohol (FA) based on about 7 nm sized Pd-Cu alloy nanoparticles (NPs) formed in inexpensive, commercially available micro/mesoporous hypercrosslinked polystyrene (HPS). A comparison of the catalytic properties of as-synthesized and reduced (denoted "r") catalysts as well as Pd-Cu alloy and monometallic palladium NPs showed a considerable enhancement of the catalytic performance of Pd-Cu/HPS-r compared to other catalysts studied, resulting in about 100 % FF conversion, 95.2 % selectivity for FA and a TOF of 1209 h
-1 . This was attributed to the enrichment of the NP surface with copper atoms, disrupting the furan ring adsorption, and to the presence of both zerovalent and cationic palladium and copper species, resulting in optimal hydrogen and FF adsorption. These factors along with exceptional stability of the catalyst in ten consecutive catalytic cycles make it highly promising in practical applications., (© 2020 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)- Published
- 2020
- Full Text
- View/download PDF
25. [Distal subtotal gastrectomy and gastreectomy in surgical treatment of patients with gastric cancer: a systematic review and meta-analysis].
- Author
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Panin SI, Postolov MP, Kovalenko NV, Beburishvili AG, Fedorov AV, and Bykov AV
- Subjects
- Gastrectomy adverse effects, Gastrectomy mortality, Humans, Lymph Node Excision methods, Margins of Excision, Randomized Controlled Trials as Topic, Gastrectomy methods, Stomach Neoplasms mortality, Stomach Neoplasms pathology, Stomach Neoplasms surgery
- Abstract
Objective: To analyze the randomized controlled trials (RCTs) devoted to distal subtotal gastrectomy and gastrectomy with D2 lymphadenectomy in patients with distal gastric cancer., Material and Methods: RCTs were searched in the electronic library, the Cochrane Community database, and PubMed database. A systematic review and meta-analysis were carried out in accordance with the recommendations of the Cochrane Community experts (Higgins et al. 2019). Mathematical calculations of a meta-analysis were made using RevMan 5.3 software package. Statistical criteria were calculated for relative risk (RR), hazard ratio (HR), 95% confidence interval (95% CI) and significance level ( p )., Results: Seven primary RCTs were selected. A total number of 1463 surgical interventions with D2 lymphadenectomy were observed (805 patients underwent distal subtotal gastrectomy, 658 - gastrectomy). Postoperative mortality is significantly higher (6.5% and 2.6%) after gastrectomy compared to subtotal distal gastrectomy (RR 2.2, 95% CI 1.34-3.64, I
2 0%, fixed effect model). Postoperative complications are also significantly more common (28% and 14%) after gastrectomy (RR 1.72, 95% CI 1.16-2.55, I2 heterogeneity 49%, random effect model). Differences in overall five-year survival after gastrectomy and subtotal distal resection (51.6% and 60.8%) are insignificant (HR 0.74, 95% CI 0.45-1.22, I2 90%, random effect model, general reverse inversion)., Conclusion: The choice of distal subtotal gastrectomy and gastrectomy with D2 lymphadenectomy in patients with distal gastric cancer is not regulated by evidence-based medicine. The boundaries of minimal surgical clearance from the tumor edge vary from 2.5 cm to 6 cm. An updated meta-analysis shows that postoperative mortality and morbidity are significantly higher after gastrectomy compared to distal subtotal gastrectomy while overall 5-year survival is similar.- Published
- 2020
- Full Text
- View/download PDF
26. Assessment of biotoxicity of Cu nanoparticles with respect to probiotic strains of microorganisms and representatives of the normal flora of the intestine of broiler chickens.
- Author
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Sizentsov AN, Kvan OV, Miroshnikova EP, Gavrish IA, Serdaeva VA, and Bykov AV
- Subjects
- Animals, Bacillus subtilis drug effects, Bacteria drug effects, Chickens microbiology, Copper toxicity, Gastrointestinal Microbiome drug effects, Metal Nanoparticles toxicity, Probiotics administration & dosage
- Abstract
Copper nanoparticle Cu (d = 55 ± 15 nm) and CuO nanoparticles (d = 90 ± 10 nm) were used in the studies (OOO Platina, Russia). Using the method of pure cultures, we extracted Lactobacillus, Enterococcus, and Enterobacterium from the intestines of broilers. Additionally, strains of Bacillus subtilis 10641 and Bifidobacterium were involved in probiotic strains. The data obtained in the course of the study testify to the insignificant biotoxicity of copper nanoparticles with respect to representatives of the genera Lactobacillus (30 to 15 μg/ml) and Bifidobacterium (30 μg/ml), with the most sensitive bacteria being the genus Lactobacillus, for which a concentration of 7.5 μg/ml was subinhibitory. The second stage was the study using method of agar wells. In the course of the experiment, we obtained results confirming the data of the research by the serial dilution method. In this case, as in the first case, the data indicate the insignificant biotoxicity of copper nanoparticles in relation to representatives of the genera Lactobacillus and Bifidobacterium. We have studied the bioaccumulating ability of microorganisms of the studied metals. In all the studies carried out, as in the first series of experiments, representatives of the genera Lactobacillus and Bifidobacterium with the lowest bioaccumulative ability were the most sensitive to copper nanoparticles and were 3.1 and 8.2%, respectively. The use of nanoparticles as a component of the fodder additive in small concentrations does not adversely affect not only the probiotic strains, but also the main representatives of the normoflora (Lactobacillus, Enterococcus, and Enterobacterium) of the poultry, the positive effect of the copper nanoparticles being directly related to low level of dissociation of nanoparticles, since biologically active ions will be released much more slowly, thereby creating a prolonged effect of exposure.
- Published
- 2018
- Full Text
- View/download PDF
27. [The first episode of spontaneous pneumothorax (errors, hazards, complications)].
- Author
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Polyantsev AA, Bykov AV, Polyantsev AA, Kotrunov VV, Zimin AG, and Dyachkova YA
- Subjects
- Adult, Clinical Decision-Making, Female, Humans, Length of Stay statistics & numerical data, Male, Middle Aged, Outcome and Process Assessment, Health Care, Pneumothorax diagnosis, Recurrence, Retrospective Studies, Russia epidemiology, Time-to-Treatment standards, Medical Errors prevention & control, Minimally Invasive Surgical Procedures adverse effects, Minimally Invasive Surgical Procedures methods, Pneumothorax surgery, Postoperative Complications epidemiology, Postoperative Complications etiology, Thoracic Surgery, Video-Assisted adverse effects, Thoracic Surgery, Video-Assisted methods, Thoracic Surgery, Video-Assisted mortality, Thoracotomy adverse effects, Thoracotomy methods, Thoracotomy mortality
- Abstract
Aim: To analyze the errors and complications of surgical care in patients with the first episode of spontaneous pneumothorax at different hospitals., Material and Methods: From 2005 to 2015 three hundreds and seventeen patients with the first episode of spontaneous pneumothorax have been treated at the thoracic department of Volgograd State Medical University. Patients were divided into 2 groups: 79 of them underwent thoracotomy while in 238 cases minimally invasive technologies were applied. Faster preoperative management and earlier active surgical tactics were suggested., Results: There were 6 the most typical violations of surgical care in 42% of patients with the first episode of spontaneous pneumothorax. Medical and diagnostic violations at regional centers and central district hospitals were the same, but there were differences in certain types of errors and their incidence. Minimally invasive technologies do not significantly affect the number of violations of thoracic surgery principles. Early procedures against the recurrence by using of thoracoscopic interventions reduce postoperative morbidity from 1.2 to 0.3% and mortality by 8.25 times.
- Published
- 2018
- Full Text
- View/download PDF
28. Effect of probiotics on the basis of Bacillus subtilis and Bifidobacterium longum on the biochemical parameters of the animal organism.
- Author
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Kvan OV, Gavrish IA, Lebedev SV, Korotkova AM, Miroshnikova EP, Serdaeva VA, Bykov AV, and Davydova NO
- Subjects
- Animals, Diet, Escherichia coli growth & development, Lactobacillus growth & development, Male, Minerals, Proteus growth & development, Rats, Rats, Wistar, Bacillus subtilis physiology, Bifidobacterium longum physiology, Gastrointestinal Microbiome, Probiotics pharmacology
- Abstract
For the purpose of safe modulation of the intestinal microflora, probiotics have been increasingly used in recent years. In the present work, the effect of the probiotic sporobacterin (Bacillus subtilis 534) (I group) and soybean-bifidum (Bifidobacterium longum) (II group) on male rats of the Wistar line was evaluated. In assessing nonspecific immunity in vitro, there was an increase in the level of baseline level in the first and second groups (by 8.3 and 12.2% more control). The influence of probiotic preparations on the intestinal normoflora was assessed using PCR. Bifidumbacterin increased the normal microflora, in particular, Escherichia coli 1.55 times, Lactobacillus 1.26 times, Enterococcus 1.3 times as much control; the level of conditionally pathogenic microflora, in particular, Proteus spp. decreased by 1.3 times in comparison with the control. Sporobacterin also contributed to an increase in the amount of E. coli (1.55 times) and Lactobacillus (0.9 times). When a culture of Bifidobacterium longum was introduced, a selective reduction in the loss of chemical elements was observed against the background of the diet used. At the end of the experiment, the content of calcium in the body tissues of animals of group II exceeded this indicator in group I by 3.9%, phosphorus by 17.6%, copper by 28.5%, and zinc by 15.2%. The totality of the results obtained by us indicates that inclusion of Bifidumbacterium longum in the diet of animals makes the use of this preparation in the correction of mineral imbalance and improves the microflora of the intestines of animals by reducing the number of representatives of opportunistic microflora against the background of an increase in the number of basic representatives of normal microbiocenosis. Also, the use of probiotic drugs as additives leads to a slight increase in the level of nonspecific immunity, which increases the natural resistance of the organism.
- Published
- 2018
- Full Text
- View/download PDF
29. Monitoring of temperature-mediated phase transitions of adipose tissue by combined optical coherence tomography and Abbe refractometry.
- Author
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Yanina IY, Popov AP, Bykov AV, Meglinski IV, and Tuchin VV
- Subjects
- Animals, Equipment Design, Lipolysis physiology, Lipolysis radiation effects, Refractometry instrumentation, Swine, Tomography, Optical Coherence instrumentation, Adipose Tissue chemistry, Adipose Tissue diagnostic imaging, Adipose Tissue physiology, Refractometry methods, Tomography, Optical Coherence methods
- Abstract
Observation of temperature-mediated phase transitions between lipid components of the adipose tissues has been performed by combined use of the Abbe refractometry and optical coherence tomography. The phase transitions of the lipid components were clearly observed in the range of temperatures from 24°C to 60°C, and assessed by quantitatively monitoring the changes of the refractive index of 1- to 2-mm-thick porcine fat tissue slices. The developed approach has a great potential as an alternative method for obtaining accurate information on the processes occurring during thermal lipolysis., ((2018) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE).)
- Published
- 2018
- Full Text
- View/download PDF
30. Influence of probe pressure on diffuse reflectance spectra of human skin measured in vivo.
- Author
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Popov AP, Bykov AV, and Meglinski IV
- Subjects
- Humans, Monte Carlo Method, Pressure, Skin blood supply, Skin diagnostic imaging
- Abstract
Mechanical pressure superficially applied on the human skin surface by a fiber-optic probe influences the spatial distribution of blood within the cutaneous tissues. Upon gradual load of weight on the probe, a stepwise increase in the skin reflectance spectra is observed. The decrease in the load follows the similar inverse staircase-like tendency. The observed stepwise reflectance spectra changes are due to, respectively, sequential extrusion of blood from the topical cutaneous vascular beds and their filling afterward. The obtained results are confirmed by Monte Carlo modeling. This implies that pressure-induced influence during the human skin diffuse reflectance spectra measurements in vivo should be taken into consideration, in particular, in the rapidly developing area of wearable gadgets for real-time monitoring of various human body parameters., ((2017) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE).)
- Published
- 2017
- Full Text
- View/download PDF
31. Multimodal optical measurement for study of lower limb tissue viability in patients with diabetes mellitus.
- Author
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Dremin VV, Zherebtsov EA, Sidorov VV, Krupatkin AI, Makovik IN, Zherebtsova AI, Zharkikh EV, Potapova EV, Dunaev AV, Doronin AA, Bykov AV, Rafailov IE, Litvinova KS, Sokolovski SG, and Rafailov EU
- Subjects
- Case-Control Studies, Female, Fluorescence, Humans, Laser-Doppler Flowmetry, Male, Microcirculation physiology, Middle Aged, Skin blood supply, Diabetes Mellitus, Type 2 complications, Diabetes Mellitus, Type 2 physiopathology, Lower Extremity blood supply, Tissue Survival physiology
- Abstract
According to the International Diabetes Federation, the challenge of early stage diagnosis and treatment effectiveness monitoring in diabetes is currently one of the highest priorities in modern healthcare. The potential of combined measurements of skin fluorescence and blood perfusion by the laser Doppler flowmetry method in diagnostics of low limb diabetes complications was evaluated. Using Monte Carlo probabilistic modeling, the diagnostic volume and depth of the diagnosis were evaluated. The experimental study involved 76 patients with type 2 diabetes mellitus. These patients were divided into two groups depending on the degree of complications. The control group consisted of 48 healthy volunteers. The local thermal stimulation was selected as a stimulus on the blood microcirculation system. The experimental studies have shown that diabetic patients have elevated values of normalized fluorescence amplitudes, as well as a lower perfusion response to local heating. In the group of people with diabetes with trophic ulcers, these parameters also significantly differ from the control and diabetes only groups. Thus, the intensity of skin fluorescence and level of tissue blood perfusion can act as markers for various degrees of complications from the beginning of diabetes to the formation of trophic ulcers., ((2017) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE).)
- Published
- 2017
- Full Text
- View/download PDF
32. Nanoparticle-free tissue-mimicking phantoms with intrinsic scattering.
- Author
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Wróbel MS, Popov AP, Bykov AV, Tuchin VV, and Jędrzejewska-Szczerska M
- Abstract
We present an alternative to the conventional approach, phantoms without scattering nanoparticles, where scattering is achieved by the material itself: spherical cavities trapped in a silicone matrix. We describe the properties and fabrication of novel optical phantoms based on a silicone elastomer polydimethylsiloxane (PDMS) and glycerol mixture. Optical properties (absorption coefficient µa , reduced scattering coefficient µs' , and anisotropy factor g) of the fabricated phantoms were retrieved from spectrophotometric measurements (in the 400-1100 nm wavelength range) using the inverse adding-doubling method. The internal structure of the phantoms was studied under a scanning electron microscope, and the chemical composition was assessed by Raman spectroscopy. Composition of the phantom material is reported along with the full characterization of the produced phantoms and ways to control their parameters.
- Published
- 2016
- Full Text
- View/download PDF
33. Role of Progenitor Cells in Liver Regeneration after Subtotal Resection.
- Author
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El'chaninov AV, Fatkhudinov TKh, Kananykhina EY, Usman NY, Arutyunyan IV, Makarov AV, Bykov AV, Bolshakova GV, and Sukhikh GT
- Subjects
- Animals, Animals, Outbred Strains, Apoptosis Regulatory Proteins metabolism, Cell Proliferation, Cytokine TWEAK, Hepatectomy, Liver surgery, Membrane Proteins metabolism, Mitosis, Organ Size, Rats, Sprague-Dawley, SOX9 Transcription Factor metabolism, Tumor Necrosis Factors metabolism, Hepatocytes physiology, Liver physiology, Liver Regeneration, Stem Cells physiology
- Abstract
In the liver of rats subjected to subtotal liver resection (80% organ weight), the expression of sox9 gene and SOX9 protein content increased and cells with hepatocyte morphology expressing SOX9 appeared; the proportion of cells expressing cytokeratin-19 also increased. Based on these data, we cannot completely exclude the involvement of resident progenitor cells and hepatocyte reprogramming in liver regeneration after subtotal resection, however, the contribution of these processes seems to be insignificant. The leading mechanism of liver mass recovery after subtotal resection is proliferation of hepatocytes.
- Published
- 2016
- Full Text
- View/download PDF
34. Use of optical skin phantoms for preclinical evaluation of laser efficiency for skin lesion therapy.
- Author
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Wróbel MS, Jedrzejewska-Szczerska M, Galla S, Piechowski L, Sawczak M, Popov AP, Bykov AV, Tuchin VV, and Cenian A
- Subjects
- Equipment Design, Equipment Failure Analysis, Humans, Laser Therapy methods, Light, Optical Devices, Skin Diseases physiopathology, Biomimetic Materials chemical synthesis, Biomimetic Materials radiation effects, Laser Therapy instrumentation, Phantoms, Imaging, Skin Diseases therapy, Skin Temperature radiation effects
- Abstract
Skin lesions are commonly treated using laser heating. However, the introduction of new devices into clinical practice requires evaluation of their performance. This study presents the application of optical phantoms for assessment of a newly developed 975-nm pulsed diode laser system for dermatological purposes. Such phantoms closely mimic the absorption and scattering of real human skin (although not precisely in relation to thermal conductivity and capacitance); thus, they can be used as substitutes for human skin for approximate evaluation of laser heating efficiency in an almost real environment. Thermographic imaging was applied to measure the spatial and temporal temperature distributions on the surface of laser-irradiated phantoms. The study yielded results of heating with regard to phantom thickness and absorption, as well as laser settings. The methodology developed can be used in practice for preclinical evaluations of laser treatment for dermatology.
- Published
- 2015
- Full Text
- View/download PDF
35. Measurements of fundamental properties of homogeneous tissue phantoms.
- Author
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Wróbel MS, Popov AP, Bykov AV, Kinnunen M, Jędrzejewska-Szczerska M, and Tuchin VV
- Subjects
- Absorption, Radiation, Anisotropy, Equipment Design, Light, Models, Biological, Nephelometry and Turbidimetry methods, Radiation Dosage, Skin, Artificial, Tomography, Optical Coherence instrumentation, Biomimetic Materials chemistry, Phantoms, Imaging, Refractometry methods, Skin cytology, Skin Physiological Phenomena, Tomography, Optical Coherence methods
- Abstract
We present the optical measurement techniques used in human skin phantom studies. Their accuracy and the sources of errors in microscopic parameters’ estimation of the produced phantoms are described. We have produced optical phantoms for the purpose of simulating human skin tissue at the wavelength of 930 nm. Optical coherence tomography was used to measure the thickness and surface roughness and to detect the internal inhomogeneities. A more detailed study of phantom surface roughness was carried out with the optical profilometer. Reflectance, transmittance, and collimated transmittance of phantoms were measured using an integrating-sphere spectrometer setup. The scattering and absorption coefficients were calculated with the inverse adding-doubling method. The reduced scattering coefficient at 930 nm was found to be 1.57±0.14 mm(−1) and the absorption was 0.22±0.03 mm(−1) . The retrieved optical properties of phantoms are in agreement with the data found in the literature for real human tissues.
- Published
- 2015
- Full Text
- View/download PDF
36. Optical clearing at cellular level.
- Author
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Kinnunen M, Bykov AV, Tuorila J, Haapalainen T, Karmenyan AV, and Tuchin VV
- Subjects
- Anisotropy, Elasticity, Erythrocytes pathology, Glucose chemistry, Glycerol chemistry, Humans, Lasers, Light, Microscopy methods, Microspheres, Optical Imaging, Polystyrenes chemistry, Scattering, Radiation, Tomography, Optical Coherence methods, Water chemistry, Optical Tweezers, Optics and Photonics
- Abstract
Strong light scattering in tissues and blood reduces the usability of many optical techniques. By reducing scattering, optical clearing enables deeper light penetration and improves resolution in several optical imaging applications. We demonstrate the usage of optical tweezers and elastic light scattering to study optical clearing [one of the major mechanisms-matching of refractive indices (RIs)] at the single particle and cell level. We used polystyrene spheres and human red blood cells (RBCs) as samples and glycerol or glucose water solutions as clearing agents. Optical tweezers kept single microspheres and RBCs in place during the measurement of light scattering patterns. The results show that optical clearing reduces the scattering cross section and increases g. Glucose also decreased light scattering from a RBC. Optical clearing affected the anisotropy factor g of 23.25-μm polystyrene spheres, increasing it by 0.5% for an RI change of 2.2% (20% glycerol) and 0.3% for an RI change of 1.1% (13% glucose).
- Published
- 2014
- Full Text
- View/download PDF
37. Multiple scattering effects in Doppler optical coherence tomography of flowing blood.
- Author
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Kalkman J, Bykov AV, Streekstra GJ, and van Leeuwen TG
- Subjects
- Cell Size, Erythrocytes cytology, Hematocrit, Humans, Blood Circulation, Monte Carlo Method, Tomography, Optical Coherence methods
- Abstract
We investigate the effect of multiple scattering on the optical coherence tomography (OCT) signal and the Doppler OCT signal of flowing blood. Doppler OCT measurements at 1300 nm are performed on flowing diluted porcine blood with hematocrit ranging between 0% and 15%. Measured blood hematocrit and mean red blood cell volume are used to calculate, using the discrete dipole approximation model, the (single) scattering coefficient and scattering anisotropy of blood. Monte Carlo simulations, based on the calculated scattering coefficients and scattering anisotropies, are compared to Doppler OCT measurements for hematocrit smaller than 10%. Good quantitative agreement between Doppler OCT measurements and Monte Carlo simulations is observed. Our measurements, calculations and simulations explain the relatively low attenuation coefficients and well preserved flow profiles measured with Doppler OCT for flowing blood. Monte Carlo simulations demonstrate the effect of the scattering anisotropy of the medium on the strength of multiple scattering effects in Doppler OCT signals. With increasing scattering anisotropy the OCT attenuation decreases; the distortion of the flow profile is strongest at intermediate scattering anisotropies (≈0.6).
- Published
- 2012
- Full Text
- View/download PDF
38. Multiple and dependent scattering effects in Doppler optical coherence tomography.
- Author
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Kalkman J, Bykov AV, Faber DJ, and van Leeuwen TG
- Subjects
- Light, Scattering, Radiation, Image Enhancement methods, Image Interpretation, Computer-Assisted methods, Laser-Doppler Flowmetry methods, Tomography, Optical Coherence methods
- Abstract
Doppler optical coherence tomography (OCT) is a technique to image tissue morphology and to measure flow in turbid media. In its most basic form, it is based on single (Mie) scattering. However, for highly scattering and dense media multiple and concentration dependent scattering can occur. For Intralipid solutions with varying scattering strength, the effect of multiple and dependent scattering on the OCT signal attenuation and Doppler flow is investigated. We observe a non-linear increase in the OCT signal attenuation rate and an increasingly more distorted Doppler OCT flow profile with increasing Intralipid concentration. The Doppler OCT attenuation and flow measurements are compared to Monte Carlo simulations and good agreement is observed. Based on this comparison, we determine that the single scattering attenuation coefficient micros is 15% higher than the measured OCT signal attenuation rate. This effect and the distortion of the measured flow profile are caused by multiple scattering. The non-linear behavior of the single scattering attenuation coefficient with Intralipid concentration is attributed to concentration dependent scattering.
- Published
- 2010
- Full Text
- View/download PDF
39. Doppler OCT imaging of cytoplasm shuttle flow in Physarum polycephalum.
- Author
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Bykov AV, Priezzhev AV, Lauri J, and Myllylä R
- Subjects
- Animals, Life Cycle Stages, Physarum polycephalum growth & development, Scattering, Radiation, Tomography, Optical Coherence instrumentation, Cytoplasm metabolism, Physarum polycephalum cytology, Tomography, Optical Coherence methods
- Abstract
The Doppler optical coherence tomography technique was applied to image the oscillatory dynamics of protoplasm in the strands of the plasmodium of slime mould Physarum polycephalum. Radial contractions of the gel-like walls of the strands and the velocity distributions in the sol-like endoplasm streaming along the plasmodial strands are imaged. The motility inhibitor effect of carbon dioxide on the cytoplasm shuttle flow and strand-wall contraction is shown. The optical attenuation coefficient of cytoplasm is estimated., (2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)
- Published
- 2009
- Full Text
- View/download PDF
40. [Pharmacoeconomic analysis of antihypertensive therapy: advantages of fixed combinations].
- Author
-
Leonova MV, Erofeeva SB, Bykov AV, and Belousov IuB
- Subjects
- Antihypertensive Agents therapeutic use, Cost of Illness, Drug Therapy, Combination, Fees, Pharmaceutical, Humans, Antihypertensive Agents economics, Economics, Pharmaceutical trends, Hypertension drug therapy, Hypertension economics, Models, Economic
- Published
- 2008
41. [Implication of piribedil (pronoran) in the treatment of Parkinson's disease; a clinical and pharmacoeconomic analysis].
- Author
-
Mil'chakova AE, Popov GR, Bykov AV, and Gekht AB
- Subjects
- Costs and Cost Analysis, Humans, Parkinson Disease economics, Treatment Outcome, Antiparkinson Agents economics, Antiparkinson Agents therapeutic use, Economics, Pharmaceutical statistics & numerical data, Parkinson Disease drug therapy, Piribedil economics, Piribedil therapeutic use
- Published
- 2008
42. [Evolution of approaches to surgical treatment of complicated cholecystitis].
- Author
-
Beburishvili AG, Bykov AV, Ziubina EN, and Burchuladze NSh
- Subjects
- Aged, Cholangiography, Cholecystectomy, Laparoscopic methods, Cholecystitis diagnostic imaging, Cholecystitis etiology, Cholecystostomy, Choledochostomy methods, Cholelithiasis complications, Cholelithiasis diagnostic imaging, Humans, Postoperative Complications mortality, Retrospective Studies, Treatment Outcome, Cholecystectomy, Laparoscopic trends, Cholecystitis surgery, Choledochostomy trends, Cholelithiasis surgery
- Abstract
More than 17 thousand surgeries for calculous cholecystitis and its complications including 560 repeated surgeries on the major bile ducts were performed. Based on this experience three stages in treatment of complicated cholecystitis are distinguished. Principal changes of surgical policy are the criteria of this division. From 1993 a tendency towards mini-invasive surgery in complicated cholecystitis was developing. Optimal terms of surgery, adequate scope improved technique improve significantly results of surgical treatment of complicated cholelithiasis.
- Published
- 2005
43. [Morpho-biochemical study of the liver and serum albumins during tetrachloromethane intoxication and administration of antihypoxants, antioxidants, and actoprotectors].
- Author
-
Dubovaia TK, Tsibulevskiĭ AIu, Deev AI, Sergeev AI, Bykov AV, Evstaf'eva NIa, and Semushin BV
- Subjects
- Animals, Benzimidazoles pharmacology, Butylated Hydroxytoluene pharmacology, Fluorescent Dyes, Male, Necrosis, Rats, Sodium Oxybate pharmacology, Spectrometry, Fluorescence, Albumins metabolism, Antioxidants pharmacology, Carbon Tetrachloride Poisoning blood, Carbon Tetrachloride Poisoning pathology, Liver pathology
- Abstract
Organism intoxication with tetrachloromethane induces a complex of transformations in the liver and serum albumins system manifested in the liver as necroses in the central lobe, dilatation of sinus capillaries and blood stasis in them, increased content of total water, and changed magneto-relaxation properties indicating decreased structurization of water. The system of serum albumins shows decreased total concentration of albumins in the serum, decreased constant of 1-(phenylamino)-8-sulfonaphthalene probe binding, increased mean number of probe binding per albumin molecule, and increased accessibility of probe in the protein-probe complex for the quencher indicating changed type of interaction between the protein and fluorescent probe. Introduction of a antihypoxant, antioxidant, or actoprotector has a positive effect on the condition of the liver and serum albumins system: The studied indices are nearly completely normalized.
- Published
- 2000
44. [Choice of optimal anesthesia in outpatient treatment of varicose veins].
- Author
-
Larin SI, Molchanov AS, and Bykov AV
- Subjects
- Adult, Decision Making, Female, Humans, Male, Retrospective Studies, Ambulatory Surgical Procedures methods, Anesthesia methods, Varicose Veins surgery
- Published
- 1997
45. [Changes in the morphofunctional status of the liver in rats with acute tetrachloromethane poisoning and their correction with antihypoxants, antioxidants and actoprotectors].
- Author
-
Dubovaia TK, Tsibulevskiĭ AIu, Sergeev AI, Bykov AV, Epifanova OR, and Evstaf'eva NIa
- Subjects
- Acute Disease, Animals, Carbon Tetrachloride Poisoning physiopathology, Drug Evaluation, Preclinical, Drug Therapy, Combination, Electron Spin Resonance Spectroscopy, Liver physiopathology, Male, Necrosis, Rats, Time Factors, Antidotes therapeutic use, Antioxidants therapeutic use, Butylated Hydroxytoluene therapeutic use, Carbon Tetrachloride Poisoning drug therapy, Liver drug effects, Sodium Oxybate therapeutic use
- Abstract
The acute tetrachlormethane intoxication leads to structural and metabolic alterations in the rat liver. Morphological changes include centrolobular necroses and blood stasis in dilated sinusoidal capillaries. Metabolic changes are manifested by an increase in the water content and time of the spin-lattice (T1) and spin-spin (T2) relaxation (this indicates a lesser degree of water structuralization and its enhanced lability), and distortion of the correlation between T1 and T2. The prophylactic administration of one of the antihypoxants, antioxidants or actoprotectors normalizes the morphofunctional condition of the liver. According to the degree of the therapeutic efficacy, the examined preparations form the following series: dibunol > gamma-sodium hydroxybutyrate > tomerzol.
- Published
- 1996
46. [Dirithromycin in the treatment of infections of the lower respiratory tract].
- Author
-
Belousov IuB, Bykov AV, Komirova VP, Malikov VE, and Minaev VI
- Subjects
- Acute Disease, Adult, Aged, Anti-Bacterial Agents adverse effects, Anti-Bacterial Agents pharmacokinetics, Chronic Disease, Drug Administration Schedule, Erythromycin adverse effects, Erythromycin analogs & derivatives, Erythromycin pharmacokinetics, Erythromycin therapeutic use, Female, Humans, Macrolides, Male, Middle Aged, Anti-Bacterial Agents therapeutic use, Bronchitis drug therapy
- Abstract
Good results of the treatment of patients with lower respiratory tract infections with dirithromycin (Eli Lilly, USA), a new semisynthetic macrolide, were recorded. The trial included 15 patients: 6 with acute bronchitis (AB) and 9 with exacerbation of chronic bronchitis (AB) and 9 with exacerbation of chronic bronchitis (ECB). The antibiotic was administered orally in a single dose of 500 mg once a day for 7 days. The treatment efficacy was estimated by the clinical results and laboratory findings. The sputum specimens were investigated bacteriologically with testing the microflora for the drug susceptibility by using the diffusion disks. 50 per cent of the patients with AB isolated Streptococcus viridans with low (the diameter of the growth inhibition zones < 16 mm) and intermediate (16-17 mm) susceptibility to the antibiotic, 33.3 per cent of the patients isolated highly susceptible (19 mm) strains of Str. pneumonia and 16.7 per cent of the patients isolated resistant (15 mm) strains of Staphylococcus epidermidis. Highly susceptible (17-19 mm) strains of Haemophilus influenzae and Str. viridans were isolated respectively from 55.5 and 45.5 per cent of the patients with ECB. In 4 patients with ECB a clinical improvement of the state was recorded. In the other patients with AB and ECB the recovery was stated. The bacteriological tests revealed a new pathogen in 2 patients with ECB and the failure of the treatment in another 2 patients with ECB. In all the other patients the pathogen was shown to be eradicated. In the patients isolating the new pathogen the symptomatic recovery was stated in the posttherapeutic period. Therefore, diritromycin proved to be efficient in 13 out of the 15 patients with lower respiratory tract infections. It should be noted that the drug tolerance was excellent. None of the patients showed any adverse reactions.
- Published
- 1995
47. [Errors in ultrasonic diagnosis of abdominal diseases].
- Author
-
Postolov PM, Zhitnikova KS, Ziubina EN, Bykov AV, Kalmykova OP, and Gal'chuk GG
- Subjects
- Acute Disease, Chronic Disease, Diagnosis, Differential, Diagnostic Errors, Humans, Liver Abscess diagnostic imaging, Subphrenic Abscess diagnostic imaging, Ultrasonography, Abscess diagnostic imaging, Biliary Tract Diseases diagnostic imaging, Liver Diseases diagnostic imaging, Pancreatitis diagnostic imaging
- Abstract
Errors in the ultrasonic diagnosis of diseases of the abdominal organs in 2,218 patients were analysed in comparison to endoscopic and operative findings. The errors were few in number. A precise diagnosis was established in 99.6% of cases with acute cholecystitis and in 78% of those with a pathological process in the biliary tract. A maximum number of errors (7 per 42 cases) was encountered in carcinoma of the gallbladder. Ultrasonic examination may serve as the basis for choosing the method of rational therapy in diseases of the liver, pancreas, and complications in the postoperative period. Thus, the results of ultrasonic examination may be fully relied on or may be used as a basis for choosing manipulations which are more invasive in character.
- Published
- 1991
48. [Contact dissolution of gallstones].
- Author
-
Postolov PM, Bykov AV, Nesterov SS, Golub VA, Mishin SG, and Burchuladze NSh
- Subjects
- Acute Disease, Caprylates, Cholecystitis etiology, Cholelithiasis surgery, Edetic Acid administration & dosage, Gallbladder surgery, Glycerides administration & dosage, Humans, Laparoscopy, Nitrates administration & dosage, Cholelithiasis therapy, Solvents administration & dosage
- Abstract
The techniques and results of contact dissolution of stones in the gallbladder of 27 patients subjected to laparoscopic cholecystostomy for acute cholecystitis were analysed. It was found that the main factors impeding effective dissolution were: the size of the stones over 1.5 cm and admixture of pigment in the concrements. The first Soviet produced litholytic preparation Oktalgin, synthesized by the authors jointly with the Zelinsky IOCh, AMS USSR, was used as the main solvent. The principal possibility of dissolving multiple stones of the gallbladder through laparoscopic cholecystostomy is proved.
- Published
- 1991
49. [Study of crystal structures of the bile in the diagnosis of gallstone composition and prognostication of the possibilities of their dissolution].
- Author
-
Postolov PM, Bykov AV, Mishin SG, Nikishin GI, Troianskiĭ EI, and Mizintsev VV
- Subjects
- Adolescent, Adult, Aged, Bilirubin analysis, Calcium analysis, Cholelithiasis diagnosis, Cholelithiasis therapy, Cholesterol analysis, Crystallization, Humans, Microscopy, Polarization, Middle Aged, Prognosis, Spectrophotometry, Infrared, Bile chemistry, Cholelithiasis chemistry
- Abstract
Bile was studied by polarizing microscopy and gallstones by infrared spectroscopy in 150 patients with cholelithiasis. It was established that the presence or absence of certain hard crystal structures in bile, determined by polarizing microscopy, reflects with sufficient accuracy the chemical composition of gallstones in patients with cholelithiasis. The high degree of correlation of the prognosticated result of litholysis on the basis of polarizing microscopy and the results of gallstone dissolution in experiments shows that the information gained in polarizing microscopy may be used as one of the most important criteria in determining the indications and contraindications for dissolving gallstones with octagline.
- Published
- 1991
50. [Effectiveness of captopril (tensiomin) in the long-term treatment of arterial hypertension].
- Author
-
Kakaliia E, Belousov IuB, Bykov AV, and Sidorskiĭ AL
- Subjects
- Adult, Aged, Blood Pressure physiology, Dose-Response Relationship, Drug, Drug Administration Schedule, Female, Humans, Hypertension physiopathology, Male, Middle Aged, Time Factors, Antihypertensive Agents administration & dosage, Blood Pressure drug effects, Captopril administration & dosage, Hypertension drug therapy
- Published
- 1991
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