Application of electroanalytical techniques for assessment of human cells

Rapid development of cell technologies stipulates the need for informative and express methods for the analysis of viability and physiological activity of human cells. We studied analytical possibilities of novel tools for comprehensive characterization of bioelectrochemical properties of living cells, e.g. surface charge of cellular membrane and redox activity of metabolites. Using Malvern Zetasizer dynamic light scattering analyzer we proposed an approach to assessment of zeta potential of human cells and detection of phosphatidylserine on their surface as an early apoptotic marker. On the basis of modified electrodes we designed sensors exhibiting high sensitivity towards electroactive cellular metabolites including antioxidants and macroergic molecules. The sensors were applied for assessment of metabolic activity/energetic status of human cells (blood cells and cell cultures). Electrochemical signal of adenine nucleotides of cells on sensor surface correlated with intracellular level of ATP according to luciferase assay and was found to be more sensitive to alteration in cell viability than conventional MTS test. On the basis of disposable screenprinted electrodes we fabricated a prototype of portable analyzer for rapid analysis of cell health (e.g. for donor cells) in less than 5 ?l volume of cell sample. Proposed tools and methods are of interest in cell transplantology, basic research and cell-based medical diagnostics

Electrochemical sensor for blood deoxyribonucleases: Design and application to the diagnosis of autoimmune thyroiditis

We designed an electrochemical sensor based on a carbon nanotube modified electrode (ME) to analyze DNA-cleaving activity. The cleavage of high molecular weight DNA resulted in an increase in the oxidation current from DNA guanine nucleotides due to a change in DNA adsorptive behavior on the surface of the ME. DNA digestion with DNAse I was accompanied by a linear increase in the DNA signal in proportion to the enzyme activity. We then proposed an assay based on the sensor for the direct assessment of the total deoxyribonuclease activity of blood serum as well as the separate detection of DNAse I and DNA abzymes. The assay was applied to analyze deoxyribonucleases in sera from 21 healthy donors and 17 patients with autoimmune thyroiditis. Our results show that the response of the sensor to DNA cleavage by blood deoxyribonucleases is a promising diagnostic criterion for autoimmune thyroiditis. This sensor can be implemented in a disposable screen-printed electrode format for application in clinical laboratories. © 2011 Springer-Verlag

Binding and purification of plasmid DNA using multi-layered carbon nanotubes

We propose a new method for the separation of nucleic acids using multi-layered carbon nanotubes (CNTs) as an adsorbent. According to agarose gel electrophoresis, oxidized water-stable CNTs adsorb certain forms of nucleic acids, such as high molecular weight RNA, chromosomal DNA, linear and denatured forms of plasmid DNA. However, CNTs do not adsorb supercoiled form of plasmid DNA. Nucleic acids bound to CNTs can be readily removed by centrifugation whereas supercoiled plasmid DNA remains in solution. Upon the addition of divalent metal ions supercoiled plasmid DNA forms relatively stable complexes with CNTs due to chelation. Thus, new details about association of nucleic acids with CNTs were revealed and stoichiometry of the complexes was estimated. Our results can be used for fine purification of supercoiled plasmid DNA for gene therapy applications as well as manipulation of nucleic acids for biosensor design. © 2011 Elsevier B.V

Current State of Natural Foci of Dangerous Infectious Diseases in the Territory of the Russian Federation

Objective of the study is to evaluate the current state of epizootic activity of natural zoonotic foci, as the basis for the development of prophylactic measures aimed at prevention of natural-focal infections during mass events. Materials and methods. Utilized have been reports from the Center of Hygiene and Epidemiology in the Republic of Tatarstan, the data provided by Rospotrebnadzor Administration in the Republic of Tatarstan over the period of 2009-2014, and literature references. Results and conclusions. The most pressing natural-focal infectious diseases are hemorrhagic fever with renal syndrome, tick-borne borreliosis, and tick-borne viral encephalitis. Yersinioses, leptospiroses, and West Nile fever are rarely registered. Tularemia infections have not been reported within the past 20 years. The period of 2009-2013 is characterized by the decrease in the numbers of carriers and vectors of the diseases, as well as epizootic activity of natural foci, which came up to minimum values in 2013. Emerged since 2014 increment in the abundance rates of the carriers and later the vectors can lead to the increase in the incidence of natural-focal diseases. In the territory of the Republic, allocated are the spatial combination areas of natural foci of the diseases of various etiology with high risk of population exposure. Previous to conduction of mass events it is necessary to enhance the epizootiological surveillance in the natural foci, the results of which lay premises for the development of complex prophylactic activities

Impact of COVID-19 on cardiovascular testing in the United States versus the rest of the world

Objectives: This study sought to quantify and compare the decline in volumes of cardiovascular procedures between the United States and non-US institutions during the early phase of the coronavirus disease-2019 (COVID-19) pandemic. Background: The COVID-19 pandemic has disrupted the care of many non-COVID-19 illnesses. Reductions in diagnostic cardiovascular testing around the world have led to concerns over the implications of reduced testing for cardiovascular disease (CVD) morbidity and mortality. Methods: Data were submitted to the INCAPS-COVID (International Atomic Energy Agency Non-Invasive Cardiology Protocols Study of COVID-19), a multinational registry comprising 909 institutions in 108 countries (including 155 facilities in 40 U.S. states), assessing the impact of the COVID-19 pandemic on volumes of diagnostic cardiovascular procedures. Data were obtained for April 2020 and compared with volumes of baseline procedures from March 2019. We compared laboratory characteristics, practices, and procedure volumes between U.S. and non-U.S. facilities and between U.S. geographic regions and identified factors associated with volume reduction in the United States. Results: Reductions in the volumes of procedures in the United States were similar to those in non-U.S. facilities (68% vs. 63%, respectively; p = 0.237), although U.S. facilities reported greater reductions in invasive coronary angiography (69% vs. 53%, respectively; p < 0.001). Significantly more U.S. facilities reported increased use of telehealth and patient screening measures than non-U.S. facilities, such as temperature checks, symptom screenings, and COVID-19 testing. Reductions in volumes of procedures differed between U.S. regions, with larger declines observed in the Northeast (76%) and Midwest (74%) than in the South (62%) and West (44%). Prevalence of COVID-19, staff redeployments, outpatient centers, and urban centers were associated with greater reductions in volume in U.S. facilities in a multivariable analysis. Conclusions: We observed marked reductions in U.S. cardiovascular testing in the early phase of the pandemic and significant variability between U.S. regions. The association between reductions of volumes and COVID-19 prevalence in the United States highlighted the need for proactive efforts to maintain access to cardiovascular testing in areas most affected by outbreaks of COVID-19 infection

Глутаровая ацидурия типа 1 у детей. Клиническое представление 46 случаев, диагностированных в России

Background. Glutaric aciduria type 1 is an autosomal recessive disease caused by mutations in the GCDH gene, which encodes the enzyme glutaryl‑CoA dehydrogenase. Metabolic crisis in type 1 glutaric aciduria is an acute life‑threatening condition that requires careful diagnosis with a number of other conditions and the immediate initiation of pathogenetic therapy.Materials and methods. Clinical manifestations, neuroimaging characteristics of the disease were studied in 46 patients with diagnosed glutaric aciduria type 1 confirmed by biochemical and molecular genetic methods. Methods: gas chromatography with mass spectrometry, tandem mass spectrometry, Sanger sequencing, chromosomal microarray analysis of the exon level.Results and discussion. A retrospective analysis of anamnestic and clinical data was carried out, and the nature and age of disease manifestation, provoking factors, a spectrum of clinical manifestations and neuroimaging data were assessed.Conclusion. How initiated treatment prevents progression of neurological symptom relief and patient adaptation. With the help of the goal, it is necessary to inform pediatricians, neurologists and neuroradiologists about this feature of the course of glutaric aciduria type 1 in order to increase the clinical alertness of this disease.Введение. Глутаровая ацидурия типа 1 – аутосомно‑рецессивное заболевание, обусловленное мутациями в гене GCDH, кодирующем фермент глутарил‑КоА дегидрогеназу. Метаболический криз при глутаровой ацидурии типа 1 – это острое жизнеугрожающее состояние, требующее тщательной дифференциальной диагностики с рядом других состояний и незамедлительного начала патогенетической терапии.Материалы и методы. Клинические проявления, нейровизуализационные характеристики болезни изучены у 46 пациентов с подтвержденным биохимическими и молекулярно‑генетическими методами диагнозом глутаровой ацидурии типа 1. Методы: газовая хроматография с масс‑спектрометрией, тандемная масс‑спектрометрия, секвенирование по Сэнгеру, хромосомный микроматричный анализ экзонного уровня.Результаты и обсуждение. Проведен ретроспективный анализ анамнестических данных, клинических, а также оценены характер и возраст манифестации болезни, провоцирующие факторы, спектр клинических проявлений и нейровизуализационные данные.Заключение. При отсутствии массового неонатального скрининга крайне важное значение имеет ранняя диагностика болезни, так как своевременно начатое лечение поможет предотвратить прогрессирование неврологической симптоматики и способствовать адаптации пациентов. С этой целью необходимо информировать врачей‑педиатров, неврологов и нейрорадиологов об особенностях протекания глутаровой ацидурии типа 1 для повышения клинической настороженности в отношении данного заболевания

Assessment of metabolic activity of human cells in solution and in polymer matrix with the use of metabolite-sensitive sensors

We developed metabolite-sensitive electrochemical sensors on the basis of electrodes modified with a thick film of carbon nanotubes. Modified electrodes provide efficient pre-adsorption of cellular metabolites and their sensitive detection using anodic square-wave voltammetry. On the electrode surface both adhered and non-adhered human cells produce three oxidation peaks at the potentials of + 0.82, + 1.05, and + 1.17 V attributed to three groups of cellular metabolites: amino acid-derived antioxidants including glutathione, guanine nucleotides, and also adenine nucleotides including ATP. The electrochemical response was well correlated with cell viability, intracellular ATP level and induction of apoptosis, as determined by independent assays. Developed sensors allow for robust and cost-effective assessment of ATP in cells in contrast to enzyme-based electrodes and conventional bioluminescent assay. Results can be used for rapid analysis of human cells for the purpose of medical diagnostics, transplantology, and toxicological screening. Additionally, we combined modified electrodes with human cells entrapped in agarose matrix. The resulting biosensor allowed for electrochemical monitoring of metabolic activity and death of cells within polymeric matrix that is of interest for tissue engineering applications. © 2012 Elsevier B.V. All rights reserved

Application of electroanalytical techniques for assessment of human cells

Rapid development of cell technologies stipulates the need for informative and express methods for the analysis of viability and physiological activity of human cells. We studied analytical possibilities of novel tools for comprehensive characterization of bioelectrochemical properties of living cells, e.g. surface charge of cellular membrane and redox activity of metabolites. Using Malvern Zetasizer dynamic light scattering analyzer we proposed an approach to assessment of zeta potential of human cells and detection of phosphatidylserine on their surface as an early apoptotic marker. On the basis of modified electrodes we designed sensors exhibiting high sensitivity towards electroactive cellular metabolites including antioxidants and macroergic molecules. The sensors were applied for assessment of metabolic activity/energetic status of human cells (blood cells and cell cultures). Electrochemical signal of adenine nucleotides of cells on sensor surface correlated with intracellular level of ATP according to luciferase assay and was found to be more sensitive to alteration in cell viability than conventional MTS test. On the basis of disposable screenprinted electrodes we fabricated a prototype of portable analyzer for rapid analysis of cell health (e.g. for donor cells) in less than 5 ?l volume of cell sample. Proposed tools and methods are of interest in cell transplantology, basic research and cell-based medical diagnostics

La Patrie : journal quotidien, politique, commercial et littéraire

19 mai 19161916/05/19 (A75)

Application of electroanalytical techniques for assessment of human cells

Rapid development of cell technologies stipulates the need for informative and express methods for the analysis of viability and physiological activity of human cells. We studied analytical possibilities of novel tools for comprehensive characterization of bioelectrochemical properties of living cells, e.g. surface charge of cellular membrane and redox activity of metabolites. Using Malvern Zetasizer dynamic light scattering analyzer we proposed an approach to assessment of zeta potential of human cells and detection of phosphatidylserine on their surface as an early apoptotic marker. On the basis of modified electrodes we designed sensors exhibiting high sensitivity towards electroactive cellular metabolites including antioxidants and macroergic molecules. The sensors were applied for assessment of metabolic activity/energetic status of human cells (blood cells and cell cultures). Electrochemical signal of adenine nucleotides of cells on sensor surface correlated with intracellular level of ATP according to luciferase assay and was found to be more sensitive to alteration in cell viability than conventional MTS test. On the basis of disposable screenprinted electrodes we fabricated a prototype of portable analyzer for rapid analysis of cell health (e.g. for donor cells) in less than 5 ?l volume of cell sample. Proposed tools and methods are of interest in cell transplantology, basic research and cell-based medical diagnostics