288 research outputs found
ЭЛЕКТРОХИМИЧЕСКИЕ СЕНСОРЫ, МОДИФИЦИРОВАННЫЕ ЗОЛОТОМ И СОЛЯМИ АРЕНДИАЗОНИЯ ДЛЯ ОПРЕДЕЛЕНИЯ МЕДИ И РТУТИ В ВОЛОСАХ ЧЕЛОВЕКА
Current article presents the results of using a solid carbon-containing electrochemical sensor modified with arenediazonium salts (ME-ADT-COOH) for the joint determination of copper and mercury in human hair. The sensitivity of the determination of copper and mercury ions using a graphite electrode modified with gold and arenediazonium salts with a substituent carboxy group is higher compared to the other carbon-containing modified electrodes. The influence of the concentration of arenediazonium tosylates with various substituents on the obtained analytical signal was studied. The conditions for the manufacturing the new carbon-containing modified electrochemical sensor have been developed. The effective surface area of the modified electrode was calculated, which was estimated using a cyclic voltammogram against the background of 0.1 M KCl with the addition of potassium hexacyanoferrate (С=5*10-4mol/l) salts and calculated using the Randles-Ševčík equation for the reversible electrode process. A linear range of determined concentrations in the voltametric determination of microelements on the arendiazonium-modified gold-graphite electrode was established - from 0.1 to 12 µg/g. The error of the determination did not exceed 25 %. The correctness of the results of the determination of copper and mercury in real objects by the “introduced-found” method, which correlates well with the known values, has been verified.Keywords: voltammetry, modifier, arenediazonium tosylates, gold-graphite electrode, copper, mercury, hairDOI: http://dx.doi.org/10.15826/analitika.2022.26.2.004G.B. Slepchenko, M.S. Ostapenko, Yu.A. Akeneev, E.S. MoiseevaNational Research Tomsk Polytechnic University,Lenina Avenue, 30, Tomsk, 634050, Russian FederationПредставлены результаты использования твердого углеродсодержащего электрохимического сенсора, модифицированного солями арендиазония (МЭ-ADT-СООН), для совместного определения меди и ртути в волосах человека. Чувствительность определения ионов меди и ртути с использованием графитового электрода, модифицированного золотом и арендиазониевыми солями с заместителем карбокси-группой, выше по сравнению с другими углеродсодержащими модифицированными электродами. Изучено влияние концентрации тозилатов арендиазония с различными заместителями на получаемый аналитический сигнал. Разработаны условия изготовления нового углеродсодержащего модифицированного электрохимического сенсора. Произведен расчет эффективной площади поверхности модифицированного электрода, которая оценивалась с помощью циклической вольтамперограммы на фоне 0.1 M KCl с добавкой солей гексацианоферрата калия (С = 5·10-4 моль/л) и рассчитывалась с использованием уравнения Рэндлса-Шевчика для обратимого электродного процесса. Установлен линейный диапазон определяемых концентраций при вольтамперометрическом определении микроэлементов на модифицированном арендиазонием золото-графитовом электроде – от 0.1 до 12 мкг/г. Погрешность их определения не превышала 25 %. Проверена корректность результатов определения меди и ртути в реальных объектах методом «введено-найдено», хорошо коррелирующего с известными значениями.Ключевые слова: вольтамперометрия, модификатор, арендиазоний тозилат, органо-модифицированный электрод, медь, ртуть, волосыDOI: http://dx.doi.org/10.15826/analitika.2022.26.2.00
COMPARATIVE RESEARCH OF ENALAPRIL AND ATENOLOL ANTIHYPERTENSIVE EFFICACY IN HIGH RISK PATIENTS
Aim. To evaluate the effecacy of enalapril (Enam, Dr.Reddy’s, India) and atenolol (Tenormin, AstraZeneca, UK) and their influence on processes of cardiovascular system remodeling in comparative research in patients with arterial hypertension. Material and methods. 38 patients with arterial hypertension stage II were examined. 21 patients were treated with enalapril (10-40 mg\d) and 17 – with atenolol (50-100 mg\d). Duration of therapy was 24 weeks. A daily monitoring of blood pressure and echocardiography were made before and after the treatment. Spontaneous erythrocyte aggregation and deformability, spontaneous platelet aggregation and adhesive property of neutrophils were also estimated. A number of leucocytes carrying activation markers and expressing adhesive molecules was calculated. The plasma concentration of adhesive molecules (ICAM-1) and von Willebrand protein as well as serum concentration of N-terminal peptide of procollagen type III was also estimated. Results. Enalapril versus atenolol improved blood rheology, reduced functional leucocytes activity, plasma concentration of von Willebrand protein and intercellular adhesive molecules. The reduction in collagen III synthesis activity in enalapril therapy was proved. A significant regress of left ventricle hypertrophy due to enalapril treatment was related with favorable non-hemodynamic effects. Conclusion. The research revealed that the blockage of tissue rennin-angiotensin system is very important in prevention of cardiovascular complications especially in high risk patients
Late Paleocene Flora of the Northern Alaska Peninsula: The Role of Transberingian Plant Migrations and Climatic Change
For the first time, the Late Sagwon Flora is described from the upper beds of the Prince Creek Formation (Upper Paleocene) at the Sagavanirktok River (northern Alaska Peninsula). The flora is dominated by the angiosperm Tiliaephyllum brooksense Moiseeva et Herman sp. nov. and conifer Metasequoia occidentalis (Newb.) Chaney. The Late Sagwon Flora is most similar to the Danian or Danian-Selandian flora from the middle part of the Upper Tsagayan Subformation (Amur Region) and lower part of the Wuyun Formation (Heilongjiang Province, China). This similarity allows us to hypothesize that the genus Tiliaephyllum, which dominated in the Late Tsagayan Flora, migrated via the Bering Land Bridge from southern paleolatitudes of the Far East to high latitudes of the Arctic Pacific, due to the progressively warming climate of the Paleocene. Additional new angiosperm species are described from the Late Sagwon Flora: Archeampelos mullii Moiseeva et Herman sp. nov., Tiliaephyllum brooksense Moiseeva et Herman sp. nov., and Dicotylophyllum sagwonicum Moiseeva et Herman sp. nov
Electrochemical sensor modified with gold and arenediazonium salts for the determination of copper and mercury in human’s hair
Представлены результаты использования твердого углеродсодержащего электрохимического сенсора, модифицированного солями арендиазония (МЭ-ADT-СООН), для совместного определения меди и ртути в волосах человека. Чувствительность определения ионов меди и ртути с использованием графитового электрода, модифицированного золотом и арендиазониевыми солями с заместителем карбокси-группой, выше по сравнению с другими углеродсодержащими модифицированными электродами. Изучено влияние концентрации тозилатов арендиазония с различными заместителями на получаемый аналитический сигнал. Разработаны условия изготовления нового углеродсодержащего модифицированного электрохимического сенсора. Произведен расчет эффективной площади поверхности модифицированного электрода, которая оценивалась с помощью циклической вольтамперограммы на фоне 0.1 M KCl с добавкой солей гексацианоферрата калия ( С = 5·10-4 моль/л) и рассчитывалась с использованием уравнения Рэндлса-Шевчика для обратимого электродного процесса. Установлен линейный диапазон определяемых концентраций при вольтамперометрическом определении микроэлементов на модифицированном арендиазонием золото-графитовом электроде - от 0.1 до 12 мкг/г. Погрешность их определения не превышала 25 %. Проверена корректность результатов определения меди и ртути в реальных объектах методом «введено-найдено», хорошо коррелирующего с известными значениями.Current article presents the results of using a solid carbon-containing electrochemical sensor modified with arenediazonium salts (ME-ADT-COOH) for the joint determination of copper and mercury in human hair. The sensitivity of the determination of copper and mercury ions using a graphite electrode modified with gold and arenediazonium salts with a substituent carboxy group is higher compared to the other carbon-containing modified electrodes. The influence of the concentration of arenediazonium tosylates with various substituents on the obtained analytical signal was studied. The conditions for the manufacturing the new carbon-containing modified electrochemical sensor have been developed. The effective surface area of the modified electrode was calculated, which was estimated using a cyclic voltammogram against the background of 0.1 M KCl with the addition of potassium hexacyanoferrate (С=5*10-4mol/l) salts and calculated using the Randles-Ševčík equation for the reversible electrode process. A linear range of determined concentrations in the voltametric determination of microelements on the arendiazonium-modified gold-graphite electrode was established - from 0.1 to 12 µg/g. The error of the determination did not exceed 25 %. The correctness of the results of the determination of copper and mercury in real objects by the “introduced-found” method, which correlates well with the known values, has been verified.Исследования и эмпирические расчеты проводятся в рамках гранта «Программы повышения конкурентоспособности Томского политехнического университета». Работа выполнена при поддержке Государственного задания «Наука» (база) № 20.0025.ГЗБ.2020. Некоторые исследования проводилисьс использованием средств центра коллективного пользования ТПУ «Физико-химические методы анализа.The research and empirical calculations were carried out as part of the Tomsk Polytechnic University Competitiveness Enhancement Program grant. The research was supported by State “Science” (base) assignment No 20.0025.GZB.2020. Some research was carried out by using the center of shared use facilities of TPU′s “Physical and chemical methods of analysis”
No effect of 14 day consumption of whole grain diet compared to refined grain diet on antioxidant measures in healthy, young subjects: a pilot study
<p>Abstract</p> <p>Background</p> <p>Epidemiological evidence supports that a diet high in whole grains is associated with lowered risk of chronic diseases included coronary heart disease, obesity, type 2 diabetes, and some types of cancer. One potential mechanism for the protective properties of whole grains is their antioxidant content. The aim of this study was to compare differences in antioxidant measures when subjects consumed either refined or whole grain diets.</p> <p>Methods</p> <p>Twenty healthy subjects took part in a randomized, crossover dietary intervention study. Subjects consumed either a refined grain or whole grain diet for 14 days and then the other diet for the next 14 days. Male subjects consumed 8 servings of grains per day and female subjects consumed 6 servings of grains per day. Blood and urine samples were collected at the end of each diet. Antioxidant measures included oxygen radical absorbance capacity (ORAC) in blood, and isoprostanes and thiobarbituric acid reactive substances (TBARS) in urine.</p> <p>Results</p> <p>The whole grain diet was significantly higher in dietary fiber, vitamin B6, folate, selenium, copper, zinc, iron, magnesium and cystine compared to the refined grain diet. Despite high intakes of whole grains, no significant differences were seen in any of the antioxidant measures between the refined and whole grain diets.</p> <p>Conclusions</p> <p>No differences in antioxidant measures were found when subjects consumed whole grain diets compared to refined grain diets.</p
A systematic evaluation of contemporary impurity correction methods in ITS-90 aluminium fixed point cells
Local therapy of cancer with free IL-2
This is a position paper about the therapeutic effects of locally applied free IL-2 in the treatment of cancer. Local therapy: IL-2 therapy of cancer was originally introduced as a systemic therapy. This therapy led to about 20% objective responses. Systemic therapy however was very toxic due to the vascular leakage syndrome. Nevertheless, this treatment was a break-through in cancer immunotherapy and stimulated some interesting questions: Supposing that the mechanism of IL-2 treatment is both proliferation and tumoricidal activity of the tumor infiltrating cells, then locally applied IL-2 should result in a much higher local IL-2 concentration than systemic IL-2 application. Consequently a greater beneficial effect could be expected after local IL-2 application (peritumoral = juxtatumoral, intratumoral, intra-arterial, intracavitary, or intratracheal = inhalation). Free IL-2: Many groups have tried to prepare a more effective IL-2 formulation than free IL-2. Examples are slow release systems, insertion of the IL-2 gene into a tumor cell causing prolonged IL-2 release. However, logistically free IL-2 is much easier to apply; hence we concentrated in this review and in most of our experiments on the use of free IL-2. Local therapy with free IL-2 may be effective against transplanted tumors in experimental animals, and against various spontaneous carcinomas, sarcomas, and melanoma in veterinary and human cancer patients. It may induce rejection of very large, metastasized tumor loads, for instance advanced clinical tumors. The effects of even a single IL-2 application may be impressive. Not each tumor or tumor type is sensitive to local IL-2 application. For instance transplanted EL4 lymphoma or TLX9 lymphoma were not sensitive in our hands. Also the extent of sensitivity differs: In Bovine Ocular Squamous Cell Carcinoma (BOSCC) often a complete regression is obtained, whereas with the Bovine Vulval Papilloma and Carcinoma Complex (BVPCC) mainly stable disease is attained. Analysis of the results of local IL-2 therapy in 288 cases of cancer in human patients shows that there were 27% Complete Regressions (CR), 23% Partial Regressions (PR), 18% Stable Disease (SD), and 32% Progressive Disease (PD). In all tumors analyzed, local IL-2 therapy was more effective than systemic IL-2 treatment. Intratumoral IL-2 applications are more effective than peritumoral application or application at a distant site. Tumor regression induced by intratumoral IL-2 application may be a fast process (requiring about a week) in the case of a highly vascular tumor since IL-2 induces vascular leakage/edema and consequently massive tumor necrosis. The latter then stimulates an immune response. In less vascular tumors or less vascular tumor sites, regression may require 9–20 months; this regression is mainly caused by a cytotoxic leukocyte reaction. Hence the disadvantageous vascular leakage syndrome complicating systemic treatment is however advantageous in local treatment, since local edema may initiate tumor necrosis. Thus the therapeutic effect of local IL-2 treatment is not primarily based on tumor immunity, but tumor immunity seems to be useful as a secondary component of the IL-2 induced local processes. If local IL-2 is combined with surgery, radiotherapy or local chemotherapy the therapeutic effect is usually greater than with either therapy alone. Hence local free IL-2 application can be recommended as an addition to standard treatment protocols. Local treatment with free IL-2 is straightforward and can readily be applied even during surgical interventions. Local IL-2 treatment is usually without serious side effects and besides minor complaints it is generally well supported. Only small quantities of IL-2 are required. Hence the therapy is relatively cheap. A single IL-2 application of 4.5 million U IL-2 costs about 70 Euros. Thus combined local treatment may offer an alternative in those circumstances when more expensive forms of treatment are not available, for instance in resource poor countries
Vicrostatin – An Anti-Invasive Multi-Integrin Targeting Chimeric Disintegrin with Tumor Anti-Angiogenic and Pro-Apoptotic Activities
Similar to other integrin-targeting strategies, disintegrins have previously shown good efficacy in animal cancer models with favorable pharmacological attributes and translational potential. Nonetheless, these polypeptides are notoriously difficult to produce recombinantly due to their particular structure requiring the correct pairing of multiple disulfide bonds for biological activity. Here, we show that a sequence-engineered disintegrin (called vicrostatin or VCN) can be reliably produced in large scale amounts directly in the oxidative cytoplasm of Origami B E. coli. Through multiple integrin ligation (i.e., αvβ3, αvβ5, and α5β1), VCN targets both endothelial and cancer cells significantly inhibiting their motility through a reconstituted basement membrane. Interestingly, in a manner distinct from other integrin ligands but reminiscent of some ECM-derived endogenous anti-angiogenic fragments previously described in the literature, VCN profoundly disrupts the actin cytoskeleton of endothelial cells (EC) inducing a rapid disassembly of stress fibers and actin reorganization, ultimately interfering with EC's ability to invade and form tubes (tubulogenesis). Moreover, here we show for the first time that the addition of a disintegrin to tubulogenic EC sandwiched in vitro between two Matrigel layers negatively impacts their survival despite the presence of abundant haptotactic cues. A liposomal formulation of VCN (LVCN) was further evaluated in vivo in two animal cancer models with different growth characteristics. Our data demonstrate that LVCN is well tolerated while exerting a significant delay in tumor growth and an increase in the survival of treated animals. These results can be partially explained by potent tumor anti-angiogenic and pro-apoptotic effects induced by LVCN
Live Imaging of Innate Immune Cell Sensing of Transformed Cells in Zebrafish Larvae: Parallels between Tumor Initiation and Wound Inflammation
Live imaging and genetic studies of the initial interactions between leukocytes and transformed cells in zebrafish larvae indicate an attractant role for H2O2 and suggest that blocking these early interactions reduces expansion of transformed cell clones
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