Time-resolved EPR study of radicals from 2,2-dimethoxy-2-phenylacetophenone in ethylene glycol after flash photolysis

The dynamic behaviour of transient free radicals generated by laser pulse photolysis (with λ = 351 nm) of 2,2-dimethoxy-2-phenylacetophenone (DMPA) in ethylene glycol solutions have been studied by time-resolved EPR at room temperature. A main result of the study is a suitable evaluation method for radical systems with CIDEP in the case of very close hyperfine lines and hence with a overlap of several signals. The evaluation of single EPR time-profile signals requires in this case to take in account also the influence of the near resonance positions, what successfully has been done. The formation and decay of the two spin polarized radicals, 7,7-dimethoxy-benzyl (R1) and benzoyl radical (R2), has been observed. For R1 the relaxation time T2 was determined with a good accuracy and the rate constants k1 and k2 were estimated by fitting the time evolution of the EPR signal at resonance and near resonance positions of the field using the Bloch equations and direct Fourier transform analysis. Radicals from DMPA in the high viscous solvent ethylene glycol have been proved to be an excellent model system for this study however the treatment is applicable also for other systems. © 2002 Elsevier Science B.V. All rights reserved

Accelerated Recovery Protocol in Extended Combined and Single-Stage Surgery for Pelvic Cancer

Introduction. The study aimed to evaluate a routine accelerated recovery management in patients with extended combined pelvic surgery.Materials and methods. We surveyed the records and outcomes in various oncological patients following the accelerated recovery protocol after a routine extended combined pelvic surgery at the Moscow City Oncology Hospital No. 1 during 2018–2020.Results and discussion. Locally advanced tumours comprised 37 (75.5 %) cases, and the remaining 12 (24.5 %) were nonpelvic resections due to metastasis. Radical surgery was achieved in 41 (83.7 %) cases, while the other 8 (16.3 %) were symptomatic due to the emerged complications of intestinal permeability disruption, bleeding, urinary obstruction, paracancrotic abscess, internal fistulae or pain syndrome. Postoperative complications were evaluated in the Clavien-Dindo classification.Conclusion. The results obtained suggest the feasibility of an accelerated recovery protocol-based practice in extended combined pelvic surgery

Complex formation, chemical exchange, species structure, and stereoselective effects in the copper(II)- L/DL-histidine systems

The formation of copper(ii) complexes with l- and dl-histidine (HisH) has been studied by means of pH-potentiometry and spectrophotometry over a wide range of pH (2-14), ligand-to-metal ratio (1:1-15:1), and temperature (15-55°C) in aqueous solutions with 1.0 mol dm -3 KNO 3 as background. Formation constants and spectral characteristics of 13 complex types were found. Fine stereoselective effects have been detected with preferential coordination of two ligands with identical configuration in Cu(His)(HisH) + and opposite configuration in Cu(His) 2. The stereoselective effect for Cu(His)(HisH) + is explained by hydrogen bond formation between the carboxyl and imidazolyl groups of neighboring ligands at cis-arrangement of amino groups (3N eq-form). The opposite sign of stereoselective effect for Cu(His) 2 is derived from favourable axial coordination of the imidazole group in meso-form with cis-structure (3N eqN ax-form). A significant tetrahedral distortion was revealed for the first time in the prevalent cis-isomer of the Cu(l-His) 2 4N eq-form. These findings were confirmed by EPR data and DFT computations at the B3LYP/TZVP level. The prevalence of cis-isomers for these complexes has been assigned to the rather strong trans effect of the amino groups. The structures of other detected complexes are briefly discussed on the basis of spectroscopic data. Chemical exchange reactions in the copper(ii)- l/dl-hishidine systems have been investigated by the NMR relaxation of water protons. A unique proton exchange reaction with short-term proton dissociation from the coordinated imidazolyl group catalyzed by hydroxide ion was characterised for the first time. The discovered enantioselective effects in the ligand exchange reactions between Cu(His) 2 and HisH or His - species were attributed to the associative substitution mechanism. © 2012 The Royal Society of Chemistry

Time-resolved ESR studies on transient radicals photogenerated in solutions of melamine in ethylene glycol

Chemically Induced Dynamic Electron Polarization (CIDEP) spectra of transient radicals generated by laser pulse with λ = 248 nm in solutions of melamine in ethylene glycol have been studied by means of time-resolved (TR) ESR at room temperature. The main products are radicals of the solvent molecules formed through abstraction of hydrogen from ethylene glycol by excited melamine molecules and a melamine radical with attached hydrogen atom on melamine. Parameters obtained from well resolved TR ESR spectra coincide with parameters of radical of ethylene glycol HOC{radical dot}HCH2OH and methylol {radical dot}CH2OH, and an unresolved ESR spectrum was attributed to the melamine radical. The electron spin polarization results from the radical pair mechanism (RPM) involving S-T0 mixing (ST0M) and additionally from a small part of triplet mechanism (TM). In order to establish the possible structure and nature of melamine radical quantum-chemical calculations by the DFT B3LYP method using several different basis sets have been done. The reaction pathway and mechanisms of alcohol and melamine radicals formation are proposed and supported by DFT calculations within B3LYP and CIS(D) methods. Melamine and ethylene glycol free radicals relaxation time T2 was estimated as 1.5 and 0.5 μs, respectively. © 2005 Elsevier B.V. All rights reserved

Electron spin resonance study of radicals generated in cellulose/N- methylmorpholine solutions after flash photolysis at 77 K

The processes of radical formation in N-methylmorpholine-N-oxide monohydrate (NMMO) and cellulose/NMMO solutions were studied by ESR at 77 K under high-power UV (λ = 248 nm) excimer laser flash photolysis. Radicals mainly generated were attributed to the nitroxide type radicals -CH 2-NO.-CH2- and -CH2-NO .-CH3 at the first step and methyl .CH 3 and formyl .CHO radicals at the second step of the photoreaction. Kinetic studies of these radicals revealed that formation and recombination rates of the radicals depend on the cellulose concentration in cellulose/NMMO solutions and the concentration of additional ingredients, e.g. Fe(II) and propyl gallate. Even at frozen state temperature, acceleration or quenching of radical reaction processes was found. The proposed scheme of UV light-induced NMMO degradation during irradiation based on ESR data correlates well with independently obtained results based on high-performance liquid chromatography (HPLC). The analysis of degradation products by HPLC, e.g. aminoethanol and acetaldehyde, supports the assumption concerning a radical-initiated ring opening of NMMO. Copyright © 2006 John Wiley & Sons, Ltd

Первичные результаты D3-лимфодиссекции при хирургическом лечении рака правой ободочной кишки

Introduction. Despite recent significant progress in chemotherapy treatment of primary non-metastatic cancer of the right half of the segmented intestine, surgery remains the primary method of treatment. Radical surgery includes removal of the tumour within the healthy tissues and regional lymph glands. Considering localisation of the primary tumour in the right half of the segmented intestine, hemicolectomy is typically performed on the right side. W. Hohenberger et al. have formulated a new concept of radical surgical treatment of the segmented intestine, consisting of the following components: complete mesocolic excision, early ligation of the lymphovascular pedicle and lymph dissection in the D3 volume.Purpose of the research: to analyse the early results of surgical treatment of cancer in the right half of the segmented intestine in the volume of the right-side hemicolectomy with D3 lymph node dissection depending on the method of surgical treatment.Materials and methods. At the premises of the Surgical Department No. 3 of the Republican Oncologic Dispensary (city of Ufa) a retrospective analysis of data of 59 patients was performed following right-side hemicolectomy using complete mesocolic excision, ligation lymphovascular pedicles and lymph node dissection in the D3 volume. Depending on the surgical access, all patients were divided into two main groups: group I (48 patients) — surgeries were performed using open method; group II (11 patients) — using laparoscopy.Results and discussion. Table 2 shows that the surgery performed with laparoscopy takes longer. However, statistically it results in significantly less blood loss. Patients who underwent open surgery were characterised by a longer stay in hospital. One of the effectiveness criteria is the number of removed lymph glands not differing for either group.Conclusion. Extended lymph dissection in the D3 volume for segmented intestine on the right side during cancer is a possible and safe method in case of laparoscopic and open procedures.Введение. Несмотря на значительный прогресс химиотерапии в последние годы, в лечении первичного неметастатического рака правой половины ободочной кишки хирургический метод является основным методом лечения. Радикальное хирургическое вмешательство включает в себя удаление опухоли в пределах здоровых тканей и регионарных лимфатических узлов. В условиях локализации первичной опухоли в правой половине ободочной кишки традиционно выполняется гемиколэктомия справа. W. Hohenberger и др. сформулировали новую концепцию радикального оперативного лечения ободочной кишки, состоящую из следующих компонентов: полная мезоколонэктомия, раннее лигирование лимфоваскулярной ножки и лимфодиссекция в объеме D3.Цель исследования: провести анализ ранних результатов хирургического лечения рака правой половины ободочной кишки в объеме правосторонней гемиколэктомии с D3-лимфодиссекцией в зависимости от метода оперативного лечения.Материалы и методы. На базе хирургического отделения № 3 Республиканского онкологического диспансера (г.  Уфа) проведен ретроспективный анализ данных 59 пациентов после правосторонней гемиколэктомии по технике complete mesocolic excision лигированием лимфоваскулярной ножки и лимфодиссекцией в объеме D3. В зависимости от оперативного доступа все пациенты были разделены на две основные группы: I группа (48 пациентов) — оперативное вмешательство проводилось открытым способом и II группа (11 пациентов) — лапароскопическим способом.Результаты и обсуждение. Из данных таблицы 2 видно, что хирургическое вмешательство, выполненное лапароскопически, оказывается более продолжительным. Однако статистически значимо сопровождалось меньшей кровопотерей. Пациенты, подвергшиеся открытой операции, характеризовались более длительным пребыванием в стационаре. Один из критериев эффективности — количество удаленных лимфоузлов — не различался для обеих групп.Заключение. Расширенная лимфодиссекция в объеме D3 при раке ободочной кишки справа является возможным и безопасным методом в случае выполнения как лапароскопических, так и открытых вмешательств

Fluconazole-Pyridoxine Bis-Triazolium Compounds with Potent Activity against Pathogenic Bacteria and Fungi Including Their Biofilm-Embedded Forms

Two novel quaternary ammonium salts, bis-triazolium derivatives of fluconazole and pyridoxine, were synthesized by reaction of fluconazole with pyridoxine-based synthetic intermediates. The leading compound demonstrated pronounced antimycotic and antibacterial in vitro activity, comparable to or exceeding that of the reference antifungal (fluconazole, terbinafine) and antibacterial/antiseptic (miramistin, benzalkonium chloride) agents. In contrast to many antimicrobials, the leading compound was also active against biofilm-embedded staphylococci and Escherichia coli. While no biofilm structure destruction occurred, all compounds were able to diffuse into the matrix and reduce the number of colony-forming units by three orders of magnitude at 16 × MBC. The leading compound was significantly less toxic than miramistin and benzalkonium chloride and more toxic than the reference antifungal drugs. The obtained results make the described chemotype a promising starting point for the development of new broad-spectrum antimicrobial therapies with powerful effect on fungal and bacterial pathogens including their biofilm-embedded forms