ХРОМАТОГРАФИЧЕСКОЕ И ХРОМАТО-МАСС-СПЕКТРОМЕТРИЧЕСКОЕ ОПРЕДЕЛЕНИЕ ПРОТИВОТУБЕРКУЛЕЗНЫХ ПРЕПАРАТОВ ОСНОВНОГО РЯДА В ПЛАЗМЕ КРОВИ

In the current study the possibility of the simultaneous determination of anti-tuberculosis (anti-TB) drugs (isoniazid, pyrazinamide, ethambutol and rifampicin) using the reversed-phase HPLC (RP-HPLC) and ion-pair chromatography was investigated. A selective and highly sensitive liquid chromatography/tandem mass spectrometry method for the simultaneous determination of four anti-TB drugs (isoniazid, pyrazinamide, ethambutol and rifampicin) in the human plasma was developed. The detection was carried out using the multiple reaction-monitoring (MRM) modes with positive polarity. The fragmentation conditions for each drug were optimized, and the conditions for the blood plasma preparation for HPLC/MS analysis, including the protein precipitation with ACN with a ratio of 3:1 (by volume), were chosen. The matrix effects on the separation and ionization of anti-TB drugs were estimated by the post-extraction additives method. It was shown that the 10-fold dilution of plasma extracts was sufficient to decrease the influence of the sample matrix. The stability of anti-TB drugs during the analysis (in autosampler at 1 and 12 hours) and at storage conditions (3 cycles of freeze-thaw) was studied. The method for increasing the stability of rifampicin using ascorbic acid (1 mg/ml) as antioxidant was provided. The LOD with UV detection were 2 – 20 µg/ml, in SIM-mode – 2 – 15 ng/ml and in MRM-mode – 0.5 – 10 ng/ml respectively. The possibility of the determination of four anti-TB drugs in real plasma samples of patients with tuberculosis undergoing drug therapy in optimized conditions HPLC/MC was shown.Key words: anti-tuberculosis drugs, RP HPLC, LC/MS/MS, matrix effect(Russian)DOI: http://dx.doi.org/10.15826/analitika.2016.20.2.007 E.A. Bessonova, L.A. Kartsova, S.A. Soloveva Saint-Petersburg State University, 7/9 Universitetskaya nab., St. Petersburg, 199034, Russian FederationВ работе выявлены возможности одновременного определения четырех противотуберкулезных препаратов (ПТП)  (этамбутол, пиразинамид, изониазид, рифампицин) методами обращённо-фазовой ВЭЖХ (ОФ ВЭЖХ) и ион-парной хроматографии.  Предложен вариант одновременного определения этих ПТП в плазме крови человека методом ОФ ВЭЖХ с тандемным масс-спектрометрическим детектированием с электроспрей ионизацией. Детектирование осуществляли в режиме положительной ионизации путём мониторинга множественных реакций (MRM). Оптимизированы условия фрагментации для каждого лекарственного вещества. Найдены условия подготовки плазмы крови к ВЭЖХ/МС анализу, включающие осаждение белков плазмы крови ацетонитрилом. Значения степеней извлечения ПТП составили 85-90 %. Проведена оценка влияния матрицы пробы на разделение и ионизацию ПТП методом пост-экстракционной добавки. Показано, что разбавление экстракта плазмы крови в 10 раз достаточно для требуемого снижения матричного эффекта.  Изучена стабильность ПТП в процессе анализа (автосамплер 1 и 12 ч.) и в условиях хранения (3 цикла заморозка-разморозка). Предложен способ увеличения стабильности рифампицина с добавлением в качестве антиоксиданта аскорбиновой кислоты (1 мг/мл). Пределы обнаружения с УФ детектированием составили от 2 до 20 мкг/мл, с МС детектированием в SIM–режиме от 2 до 15 нг/мл и в MRM–режиме от 0.5 до 10 нг/мл. В оптимизированных условиях показана возможность обнаружения и количественного определения всех четырех ПТП в плазме крови больного туберкулезом с проводимой лекарственной терапией. Ключевые слова: противотуберкулёзные препараты, ОФ ВЭЖХ, масс-спектрометрическое детектирование, матричный эффект, стабильность рифампицинаDOI: http://dx.doi.org/10.15826/analitika.2016.20.2.00

Values and preferences for hepatitis C self-testing among people who inject drugs in Kyrgyzstan

Background: The prevalence of hepatitis C virus (HCV) among people who inject drugs (PWID) continues to be a major public-health burden in this highly stigmatised population. To halt transmission of HCV, rapid HCV self-testing kits represent an innovative approach that could enable PWID to know their HCV status and seek treatment. As no HCV test has yet been licenced for self-administration, it is crucial to obtain knowledge around the factors that may deter or foster delivery of HCV self-testing among PWID in resource-constrained countries. Methods: A qualitative study to assess values and preferences relating to HCV self-testing was conducted in mid-2020 among PWID in the Bishkek and Chui regions of Kyrgyzstan. Forty-seven PWID participated in 15 individual interviews, two group interviews (n = 12) and one participatory action-research session (n = 20). Responses were analysed using a thematic analysis approach with 4 predefined themes: awareness of HCV and current HCV testing experiences, and acceptability and service delivery preferences for HCV self-testing. Informants’ insights were analysed using a thematic analysis approach. This research received local ethics approval. Results: Awareness of HCV is low and currently PWID prefer community-based HCV testing due to stigma encountered in other healthcare settings. HCV self-testing would be accepted and appreciated by PWID. Acceptability may increase if HCV self-testing: was delivered in pharmacies or by harm reduction associations; was free of charge; was oral rather than blood-based; included instructions with images and clear information on the test’s accuracy; and was distributed alongside pre- and post-testing counselling with linkage to confirmatory testing support. Conclusions: HCV self-testing could increase awareness of and more frequent testing for HCV infection among PWID in Kyrgyzstan. It is recommended that peer-driven associations are involved in the delivery of any HCV self-testing. Furthermore, efforts should be maximised to end discrimination against PWID at the healthcare institutions responsible for confirmatory HCV testing and treatment provision. © 2021, The Author(s)

РАЗДЕЛЕНИЕ СТЕРОИДНЫХ ГОРМОНОВ МЕТОДОМ МИКРОЭМУЛЬСИОННОЙ ЭЛЕКТРОКИНЕТИЧЕСКОЙ ХРОМАТОГРАФИИ С УЧАСТИЕМ ИОННЫХ ЖИДКОСТЕЙ

Microemulsion electrokinetic chromatography (MEEKC) is a promising method for separating ionic and neutral analytes in the complex matrix, where a microemulsion is used as the background electrolyte. Current work identified the possibility of using hydrophilic ionic liquids (ILs) based on imidazole (C12MImCl, C16MImCl) as modifiers and surfactants, as well as hydrophobic ILs (C6MImBF4) as an “oil” in the microemulsion for the separation of steroid hormones by MEEKC. The factors such as ILs concentration, nature and pH of the background electrolyte, and the ratio of the components of the microemulsion, that influence the efficiency and separation selectivity of analytes were found. Suitable conditions for the complete separation of a model mixture of steroid hormones: cortisol, cortisone, 11-deoxycortisol, 11-deoxycorticosterone, corticosterone were obtained. The analytical characteristics of methods (optimized conditions) for the determination of steroids by micellar and microemulsion electrokinetic chromatography were compared. It was investigated that the addition of 15 mM 2-hydroxypropyl-β-cyclodextrin increases the separation selectivity and reduces the analysis time. The application of the on-line concentration methods made it possible to reduce the detection limits of analytes to 50 ng / ml. The mode for electrophoretic determination of steroid hormones in biological fluids (urine, blood serum) by MEEKC with the use of ionic liquids has been proposed using the previously obtained results.         Keywords: imidazolium ionic liquids, steroid hormones, microemulsion electrokinetic chromatography, microemulsionDOI: http://dx.doi.org/10.15826/analitika.2019.23.2.001(Russian)L.A. Kartsova, E.A. Bessonova, D.O. Moskvichev Saint-Petersburg State University, Institute of Chemistry, 26 Universitetskii prospect, St. Petersburg, Petergof, 198504, Russian Federation В работе выявлены перспективы применения гидрофильных ионных жидкостей (ИЖ) на основе имидазола (C12MImCl, C16MImCl) в качестве модификаторов и поверхностно-активных веществ (ПАВ), а также гидрофобных ИЖ (C6MImBF4) как «масла» в составе микроэмульсии при разделении стероидных гормонов методом микроэмульсионной электрокинетической хроматографии (МЭЭКХ). Определены  факторы (концентрация ионной жидкости, природа и значение рН фонового электролита, соотношение различных компонентов микроэмульсии), влияющие на эффективность и селективность разделения аналитов. Найдены подходящие условия для полного разделения модельной смеси стероидных гормонов: кортизола, кортизона, 11-дезоксикортизола, 11-дезоксикортикостерона, 11-дегидрокортикостерона. Проведено сопоставление аналитических характеристик методов мицеллярной и микроэмульсионной электрокинетической хроматографии  при определении стероидов. Обнаружено, что добавка 15 мМ 2-гидроксипропил-β-циклодекстрина привела к увеличению селективности разделения, и при этом время анализа уменьшилось.  Применение методов on-line концентрирования позволило снизить пределы обнаружения аналитов до 50 нг/мл. На основании полученных результатов предложен экспрессный способ определения стероидных гормонов в образцах мочи и сыворотки  крови методом  МЭЭКХ с введением имидазолиевой ионной жидкости в состав фонового электролита.Ключевые слова:  имидазолиевые ионные жидкости, стероидные гормоны, микроэмульсионная электрокинетическая хроматогрофия, микроэмульсияDOI: http://dx.doi.org/10.15826/analitika.2019.23.2.00

ON-LINE КОНЦЕНТРИРОВАНИЕ БИОГЕННЫХ АМИНОВ МЕТОДОМ КАПИЛЛЯРНОГО ЭЛЕКТРОФОРЕЗА С ИCПОЛЬЗОВАНИЕМ СИНТЕЗИРОВАННЫХ КОВАЛЕНТНЫХ ПОКРЫТИЙ НА ОСНОВЕ ИОННЫХ ЖИДКОСТЕЙ

Covalent coatings of internal quartz capillary walls based on the ionic liquids were synthesized within this research. The synthesis of the covalent coating included a step of silylation followed by the functionalization with imidazole and 1-bromobutane. The resulting coating created anodic electroosmotic flow (EOF) at pH = 2. The range of pH at which coatings do not change their properties was 2.0-5.5. The possibilities of different ways of on-line concentration (large volume sample stacking, head-column field-amplified sample stacking, sweeping, sweeping in combination with electrostacking) of catecholamines were examined. Stacking efficiency factors (SEF) were 105-135 and the detection limits were decreased to 11-17 ng/ml for analytes under the large volume sample stacking.  Under the sweeping conditions, sodium dodecyl sulfate (micelle forming agent) was sorbed on the modified walls, provided a negative charging surface and acted as a strong cation exchanger. This fact led to the additional reserves in the separation selectivity of catecholamines. Under the electrostacking, the values of SEF were above 1000 and the detection limits were reduced to 1-2 ng/ml. An approbation of established patterns in the analysis of urine samples was carried out.Keywords: covalent coating, ioniс liquids, biogenic amines, on-lineconcentration(Russian)DOI: http://dx.doi.org/10.15826/analitika.2017.21.1.006E.A. Kolobova1,2, L.A. Kartsova1, E.A. Bessonova1, A.V. Kravchenko1 1Saint-Petersburg State University, Institute of Chemistry, 26 Universitetskii prospect, St. Petersburg, Petergof 198504, Russian Federation2The Nikiforov Russian Center of Emergency and Radiation Medicine, 54 Optikov st.,St. Petersburg, 199034, Russian FederationВ работе предложен вариант синтеза ковалентных покрытий внутренних стенок кварцевого капилляра на основе имидазолиевой ионной жидкости (ИЖ), включающий стадию силилирования с последующей функционализацией имидазолом и 1-бромбутаном. Полученные покрытия создавали анодный электроосмотический поток (ЭОП) при рН = 2. Рабочий диапазон рН фонового электролита, при котором синтезированные покрытия не меняют своих характеристик, составляет 2.0-5.5. Выявлены возможности различных вариантов on-line концентрирования (стэкинг с большим объемом вводимой пробы и «водной пробкой», свипинг, свипинг в сочетании с электростэкингом) катехоламинов. При стэкинге с большим объемом вводимой пробы факторы концентрирования (SEF) аналитов составили 105-135, а пределы обнаружения снижены до 11-17 нг/мл. В варианте свипинга, мицеллообразующий агент – додецилсульфат натрия, сорбируясь на модифицированных стенках, обеспечивал поверхности отрицательный заряд и выполнял роль сильного катионообменника, что приводило к дополнительным резервам в селективности разделения аналитов. При электростэкинге значения факторов концентрирования биогенных аминов превысили 1000, а пределы обнаружения удалось снизить до 1-2 нг/мл. Проведена апробация установленных закономерностей при анализе образцов мочи.Ключевые слова: ковалентные покрытия, ионные жидкости, биогенные амины, on-lineконцентрированиеDOI: http://dx.doi.org/10.15826/analitika.2017.21.1.00

Chromatographic and liquid chromatography-tandem-mass spectrometry determination of first-line anti-tuberculosis drugs in human plasma

В работе выявлены возможности одновременного определения четырех противотуберкулезных препаратов (ПТП) ( этамбутол, пиразинамид, изониазид, рифампицин ) методами обращённо-фазовой ВЭЖХ (ОФ ВЭЖХ) и ион-парной хроматографии. Предложен вариант одновременного определения этих ПТП в плазме крови человека методом ОФ ВЭЖХ с тандемным масс-спектрометрическим детектированием с электроспрей ионизацией. Детектирование осуществляли в режиме положительной ионизации путём мониторинга множественных реакций (MRM). Оптимизированы условия фрагментации для каждого лекарственного вещества. Найдены условия подготовки плазмы крови к ВЭЖХ/МС анализу, включающие осаждение белков плазмы крови ацетонитрилом. Значения степеней извлечения ПТП составили 85-90 %. Проведена оценка влияния матрицы пробы на разделение и ионизацию ПТП методом пост-экстракционной добавки. Показано, что разбавление экстракта плазмы крови в 10 раз достаточно для требуемого снижения матричного эффекта. Изучена стабильность ПТП в процессе анализа (автосамплер 1 и 12 ч.) и в условиях хранения (3 цикла заморозка-разморозка). Предложен способ увеличения стабильности рифампицина с добавлением в качестве антиоксиданта аскорбиновой кислоты (1 мг/мл). Пределы обнаружения с УФ детектированием составили от 2 до 20 мкг/мл, с МС детектированием в SIM-режиме от 2 до 15 нг/мл и в MRM-режиме от 0.5 до 10 нг/мл. В оптимизированных условиях показана возможность обнаружения и количественного определения всех четырех ПТП в плазме крови больного туберкулезом с проводимой лекарственной терапией.In the current study the possibility of the simultaneous determination of anti-tuberculosis (anti-TB) drugs (isoniazid, pyrazinamide, ethambutol and rifampicin) using the reversed-phase HPLC (RP-HPLC) and ion-pair chromatography was investigated. A selective and highly sensitive liquid chromatography/tandem mass spectrometry method for the simultaneous determination of four anti-TB drugs (isoniazid, pyrazinamide, ethambutol and rifampicin) in the human plasma was developed. The detection was carried out using the multiple reaction-monitoring (MRM) modes with positive polarity. The fragmentation conditions for each drug were optimized, and the conditions for the blood plasma preparation for HPLC/MS analysis, including the protein precipitation with ACN with a ratio of 3:1 (by volume), were chosen. The matrix effects on the separation and ionization of anti-TB drugs were estimated by the post-extraction additives method. It was shown that the 10-fold dilution of plasma extracts was sufficient to decrease the influence of the sample matrix. The stability of anti-TB drugs during the analysis (in autosampler at 1 and 12 hours) and at storage conditions (3 cycles of freeze-thaw) was studied. The method for increasing the stability of rifampicin using ascorbic acid (1 mg/ml) as antioxidant was provided. The LOD with UV detection were 2 - 20 µg/ml, in SIM-mode - 2 - 15 ng/ml and in MRM-mode - 0.5 - 10 ng/ml respectively. The possibility of the determination of four anti-TB drugs in real plasma samples of patients with tuberculosis undergoing drug therapy in optimized conditions HPLC/MC was shown

Research of <i>PNPLA3</i> I148M Gene Polymorphism in Patients with Non-Alcoholic Fatty Liver Disease, with Liver Cirrhosis and with Hepatocellular Carcinoma

Aim: to determine the frequency of PNPLA3 rs738409 C&gt;G gene polymorphism, leading to p.I148M substitution, in patients with non-alcoholic fatty liver disease (NAFLD), and to reveal the association between polymorphism and probable NAFLD outcomes: liver cirrhosis (LC) and hepatocellular carcinoma (HCC).Materials and methods. The study was conducted according to the “case-control” design, three main groups were formed: a group with NAFLD (n = 46), a group with LC (n = 61), a group with HCC (n = 50), as well as a control group (n = 70), for all groups we performed genotyping of the rs738409 polymorphism of the PNPLA3 gene. The relationship between the occurrence of different genotype variants and the diagnosis of patients was evaluated, the odds ratio (OR) of progression of NAFLD and the reliability of intergroup differences were determined.Results. NAFLD patients with PNPLA3 I148M polymorphism have a significantly higher chance of developing LC and HCC. The odds ratio for the GG genotype was 7.94 (95 % Cl: 2.19–28.84; p = 0.030) for LC and 6.51 (95 % Cl: 1.15–4.08; p = 0.039) — for HCC with concomitant LC. The presence of the minor G allele also increases the likelhood of transition from NAFLD to LC (OR = 2.38; 95 % Cl: 1.41–4.02; p = 0.010) and HCC in the presence of cirrhosis (OR = 2.17; 95 % Cl: 1.15–4.08; p = 0.039). Differences in the frequency of PNPLA3 polymorphism between the NAFLD and HCC groups were not significant. Additional risk factors for HCC associated with NAFLD are overweight (OR = 5.14; 95 % Cl: 1.94–13.67; p &lt; 0.001), arterial hypertension (OR = 8.49; 95 % Cl: 3.05–23,62; p &lt; 0.001) and diabetes mellitus (OR = 8.57; 95 % Cl: 1.03–71.48; p = 0.032).Conclusion. The frequency of single nucleotide polymorphism PNPLA3 significantly differs in patients with NAFLD, cirrhosis and HCC compared with the control group of healthy volunteers. The PNPLA3 I148M polymorphism increases the incidence of NAFLD progression to cirrhosis and HCC, but only with concomitant cirrhosis

Subsets of cerebrospinal fluid lymphocytes in acute pediatric respiratory viral infection with meningeal syndrome

Current urgency of studying the intrathecal cellular immune response to infections of central nervous system is determined by limited knowledge on existing data about mechanisms of the brain immune protection in normal and diseased state. Implication of multi-colour flow cytometry in clinical laboratory diagnostics allowed to perform detailed studies of biological liquors, including cerebrospinal fluid (CSF). Currently, however, there are only scarce data on the lymphocyte subpopulations in CSF. Appropriate reference values remain a challenging issue. A study of CSF lymphocyte pool in absence of definite results at previous examination may be a potential way to resolve this problem. These clinical conditions include acute respiratory viral infections (ARVI), presenting with pseudomeningitidis (meningism) syndrome. The aim of this work was to characterize the subsets of lymphocytes from CSF of the children with ARVI with the meningism symptoms in order to get basic (control) values for diagnostics of inflammatory brain diseases. We have studied subpopulation composition of the CSF lymphocytes form in 27 children with ARVI complicated by the meningism (pseudomeningitidis) by means of flow cytometry using FACSCalibur analyzer with BD MultiTEST IMK Kit reagents. The data evaluation was performed with FlowJo software. We have studied relative contents of the main subsets, i.e., total Т cells (CD3+); Т helpers (CD3+CD4+Th); cytotoxic T cells (CD3+CD8+CTL); natural killers (СD3-CD16+CD56+NK); В cells (CD3-CD19+), and minor lymphocyte subpopulations: double-positive (DP) (CD3+CD4+CD8+); double-negative (DN) (CD3+CD4-CD8-) T cells; NKT (СD3+CD16+CD56+); CD3+CD8bright, CD3+CD8dim, CD3-CD8+NK. Statistical evaluation was carried out with standard GraphPad Prism 5 software. Among the main lymphocyte populations in CSF, T cell were predominant (96.2%), as well as their subpopulations, i.e., CD4Th (53.4%), and CD8+CTL (28.2%), with low amounts of NK (2.2%) and B cells (0.7%). The mean relative content of minor subpopulations (DN or DP T cells, and NKT cells) was, respectively, 5.3, 4.0, and 9%. Age dependence was revealed for the contents of major and minor lymphocyte subsets. With advancing age of the children, the relative numbers of CD3+ and CD4+Тh cells in CSF increase, as well as CD4/CD8 ratio, associated with decreased share of NK cells, like as DN and CD3+CD8dimТ cells. The results obtained are reflect some features of lymphocyte pool in CSF of the children without inflammatory process in CNS. Thus, they may be referred as control values (inflammation-free brain disorders) when studying immune pathogenesis of neuroinfections and other inflammatory diseases of CNS in the children from different age groups