94 research outputs found

    A Morphometric Study of the 11th –18th Centuries AD Cranial Series from Russian Cities

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    Anthropological features of the Russian city population in the 11th – 18th centuries were studied using classical methods of craniometry as well as cranio- and osteoscopy. However, the method of geometric morphometry, which has been actively used since the 1990s and is a recent morphometric tool, has not yet been applied to Russian urban craniological series. We obtained and analyzed by the GM method three-dimensional copies of 225 skulls from thirteen series of the Middle Ages and the Early Modern period from the excavations of the Institute of Archaeology of the Russian Academy of Sciences. Despite the small number of studied samples from Tver and Torzhok, we were able to trace their features and originality relative to other comparable groups and among themselves. Based on historical information, these variations can be explained by political factors. The differences between the political systems of Ancient Rus’ and Russia in the Early Modern period also explain the greater morphological homogeneity of the urban population in the 15th – 18th centuries compared to the 11th –13th centuries. The study of variability in the late urban series and comparison of diachronic samples from Yaroslavl and Pereslavl-Zalessky showed morphological similarity between the inhabitants of the Middle Ages and the Early Modern period, which may indicate the constancy of administrative, trade, and economic ties, as well as the significant contribution of the local rural population to the formation of the anthropological appearance of the townspeople. The revealed greater variability in the female samples compared to the male ones may indicate significant irregularities in the facial skeleton shape of women, which cannot be disclosed using classical craniology data. In general, the obtained results not only confirm many of the conclusions of previous craniological studies of the urban population from Eastern Europe but also make it possible to obtain new data on the degree of homogeneity of the townspeople’s anthropological appearance in the Middle Ages and Early Modern periods

    Comparative evaluation of recommendations for preclinical studies of transporter-mediated drug–drug interactions

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    Scientific relevance. Sound recommendations for preclinical studies of transporter- mediated pharmacokinetic interactions of medicinal products can help increase the likelihood of identifying potentially nephrotoxic and hepatotoxic medicinal products at the development and authorisation stages. However, overly strict requirements for the number of studies to be performed may lead to a significant increase in the cost of finished medicinal products.Aim. The aim was to compare regulatory documents on studying transporter-mediated drug–drug interactions (DDIs).Discussion. This review examines changes in regulatory requirements for studying DDIs in chronological order from the first guidelines that appeared in 1997. As exemplified in this article, the multiplicity of transporters and the lack of specific inhibitors pose significant challenges in assessing the role of a particular transporter in drug distribution and drug–drug interactions. This comparative review shows that extrapolating from in vitro transporter inhibition studies to in vivo pharmacokinetics can be misleading.Conclusions. A unified approach to studying transporter-mediated DDIs will increase the likelihood of identifying potentially toxic agents at the stage of new molecule screening. At the same time, it is advisable to limit the number of in vitro and in vivo transporter studies and recommend conducting these studies only for medicinal products with a narrow therapeutic index

    Experimental Cell Line Models for Nephrotoxicity Screening

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    The aim of the study was to review literature data on cell models for experimental assessment of drug nephrotoxicity in vitro. Because of nephrotoxicity, 2% of new investigational medicinal products are discarded at the stage of preclinical in vivo studies in laboratory animals, and 19%—after phase 3 clinical trials. Prediction of toxicity in cell models could make drug development more cost-effective and help to reduce/avoid animal testing. At present, there are no official international guidelines for assessment of nephrotoxicity in vitro, but there is a lot of research underway. The main toxicity target in kidneys is renal proximal tubule epithelial cells, therefore the main research is focused on the development of renal proximal tubule epithelial cell lines with stable functional characteristics. Another important aspect in nephrotoxicity modeling is the choice of relevant test methods and end points which would reflect potential toxicity mechanisms. The paper reviews existing human renal proximal tubule epithelial cell lines and current test methods for assessing cytotoxicity. Promising areas for future development of cell models for nephrotoxicity assessment— are optimisation and standardisation of in vitro systems that would help to make preclinical predictions of drug nephrotoxicity in vivo

    Susceptibility of HEK293 and RPTEC Cell Lines to Nephrotoxic Effects of Cefuroxime and Cefepime: A Comparative Study

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    Researchers need to identify the nephrotoxic properties of medicinal products both during preclinical development and when exploring options to optimise pharmacotherapy. The main challenge is to find an experimental model for assessing drug-induced nephrotoxicity that reflects in vivo conditions as closely as possible.The aim of the study was to compare the susceptibility of HEK293 and RPTEC cell lines used as experimental models for assessing the nephrotoxicity of cefuroxime and cefepime.Materials and methods. The study investigated HEK293 and RPTEC cell lines cultured on plates with 0.4 µm pore membrane inserts. The cell lines were incubated for 3 days with cefuroxime and cefepime (cephalosporins excreted primarily by the kidneys). The medicinal products were added to the basal part of the well at concentrations of 50 and 150 µg/mL (cefuroxime) or 30 and 120 µg/mL (cefepime) twice a day. After incubating the cells with cefuroxime and cefepime for 24, 48, and 72 hours, the authors determined the expression levels of the SLC22A6 and SLC22A8 genes encoding organic anion transporters by a reverse transcription polymerase chain reaction. The authors considered caspase 3 and caspase 7 activation indicative of the nephrotoxic effect of cephalosporins; they evaluated this indicator by a fluorometric assay after 24, 48, and 72 hours of incubation.Results. According to the study, the expression of the SLC22A6 and SLC22A8 genes decreased with cephalosporin transport in both cell lines. The decrease occurred in the RPTEC cell line earlier than in the HEK293 cell line. The authors observed caspase 3 and caspase 7 activation only in the RPTEC cell line after incubation with cefuroxime and cefepime at low concentrations (50 and 30 µg/mL, respectively) for 72 hours and at high concentrations (150 and 120 µg/mL, respectively) for 24 hours.Conclusions. The RPTEC cell line exhibits higher susceptibility to cefuroxime and cefepime toxic effects than the HEK293 cell line due to higher transporter gene expression. Higher cephalosporin concentrations accelerate caspase 3 and caspase 7 activation in the RPTEC cell line. The experimental model based on the RPTEC cell line is a promising tool for the analysis of the nephrotoxic properties of a wide range of medicinal products

    Vitrification of a monatomic 2D simple liquid

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    A monatomic simple liquid in two dimensions, where atoms interact isotropically through the Lennard-Jones-Gauss potential [M. Engel and H.-R. Trebin, Phys. Rev. Lett. 98, 225505 (2007)], is vitrified by the use of a rapid cooling technique in a molecular dynamics simulation. Transformation to a crystalline state is investigated at various temperatures and the time-temperature-transformation (TTT) curve is determined. It is found that the transformation time to a crystalline state is the shortest at a temerature 14% below the melting temperature Tm and that at temperatures below Tv = 0.6 Tm the transformation time is much longer than the available CPU time. This indicates that a long-lived glassy state is realized for T < Tv.Comment: 5pages,5figures,accepted for publication in CEJ

    NMR spectroscopy study of the structure of hypromellose phthalate, a component of enteric coatings of medicinal products

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    Scientific relevance. Hypromellose phthalate is a component of enteric coatings used to modify active substance release from oral medicinal products in the small intestine. The release rate directly depends on the non-stoichiometric composition of the polymer, first of all, on the proportion of phthalate groups in the macromolecule. It is therefore necessary to develop reliable analytical procedures for determining the structure of hypromellose phthalate to evaluate the dissolution rate of medicinal products containing the polymer.Aim. The study aimed to develop an analytical procedure for quantifying the proportion of phthalate groups in hypromellose phthalate samples using NMR spectroscopy and to determine the relationship between the polymer dissolution rate in aqueous buffer solutions and its structural features (degree of molar substitution and molecular mass).Materials and methods. The study examined hypromellose phthalate samples isolated from enteric coatings of proton-pump inhibitors and used the reference standard for hypromellose phthalate. The non-stoichiometric composition of the polymer was determined by 13C NMR spectroscopy.Results. The authors established the conditions required to separate hypromellose phthalate from the other coating components and identified the characteristic 13C NMR signals that may be used to differentiate between the structural fragments of hypromellose phthalate. The study demonstrated the relationship between the dissolution rate and the structure of the polymer. Commercial grades of hypromellose phthalate were shown to differ in composition and, as a result, in their dissolution kinetics (in particular, the threshold pH for the onset of dissolution (5.0–5.5), as well as the dissolution rates at the same pH).Conclusions. The authors developed NMR-based procedures to determine the proportion of phthalate groups on the basis of their mass fraction in a weighted hypromellose phthalate sample and the degree of molar substitution of the polymer. The results support the applicability of these analytical procedures to the characterisation of sample composition in polymer dissolution rate studies. In principle, it is possible to derive a multiple linear regression equation that describes the dissolution rate of hypromellose phthalate as a function of the molecular mass and the molar substitution with phthalate groups. Further investigation of a larger number of polymer samples with different compositions is needed to improve the regression model and demonstrate its statistical significance. In addition to the proportion of phthalate groups, the pharmacopoeial analysis of hypromellose phthalate should also control the molecular mass of the polymer

    Determination of the Degree of Unsaturation in Essential Oils

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    Being widely used, medicinal products based on vegetable oils require strict regulation and evaluation of quality attributes, determination of shelf-life periods, and monitoring of storage conditions. The most common testing method for unsaturated compounds in vegetable oils is the iodine value determination, which has a range     of limitations. An alternative method for determining the degree of unsaturation is based on epoxidation.The aim of the study was to evaluate the possibility of determining the degree of unsaturation of terpenoids and essential oils using peroxycarboxylic acids.Materials and methods. The authors performed epoxidation of linalool, myrcene, and lemon oil with peroxydecanoic and peroxyoctanoic acids, followed by iodometric titration of the excess acid.Results. The study demonstrated the possibility of measuring the degree of unsaturation of the selected essential oil and terpenoids using peracid epoxidation.   The authors developed a procedure for determining the iodine value of essential oils and calculated the iodine values of linalool, myrcene, and lemon oil. Epoxidation proceeded as a second-order reaction. The authors obtained the following reaction rate constants: 3.9 L×mol–1×min–1 for linalool (298 К), 1.76 L×mol–1×min–1 for myrcene converting to monoxide (298 К), 0.044 L×mol–1×min–1 for myrcene epoxide converting to diepoxide (298 К), and 3.9 L×mol–1×min–1 for lemon oil (297 К).Conclusions. The suggested procedure involving peracid titration for rapid and efficient determination of the degree of unsaturation (iodine value) provides a potential basis for developing a quantification method for total unsaturated bioactive compounds in essential oils

    NMR Spectroscopy Study of the Effect of the Molecular Mass of Hypromellose Phthalate on Its Solubility

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    Scientific relevance. Hypromellose phthalate is used in enteric coatings for oral medicinal products. The proportion of phthalate groups in the polymer is standardised because it has a significant effect on solubility. Whereas, the molecular mass of hypromellose phthalate is not controlled, and its impact on solubility in media with different pH values is understudied.Aim. The study aimed to employ NMR spectroscopy to investigate the effect the molecular mass of hypromellose phthalate may have on the dissolution kinetics at the pH value declared by the polymer manufacturer.Materials and methods. The study analysed hypromellose phthalate isolated from proton-pump inhibitor enteric coatings and the hypromellose phthalate reference standard. The molecular mass of the polymer was estimated by diffusion-ordered NMR spectroscopy (DOSY) with polyethylene glycols of known molecular masses for calibration. The authors studied the dissolution profiles of hypromellose phthalates of different molecular masses using 1H NMR spectra.Results. The authors developed a procedure for estimating the average molecular mass of hypromellose phthalate by DOSY. The procedure showed variations in the molecular mass of the polymer in the test samples; the molecular mass scatter amounted to 10 kDa. The dissolution profile of the test samples in an aqueous buffer solution (pH 5.59) was described by a linear function during the first hour. The slope characterising the dissolution rate varied from 10° to 36°.Conclusions. The variation in the molecular mass of hypromellose phthalate significantly affects the dissolution rate of the test samples. The function of the dissolution rate against the molecular mass of hypromellose phthalate is non-linear. The article provides a compelling reason for further research to derive a correlation equation for the dissolution rate of hypromellose phthalate as a function of two variables (molecular mass and proportion of phthalate groups in the polymer)

    Nephrotoxicity Biomarkers: Role and Significance in the Diagnosis of Drug-Induced Kidney Injury

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    Drug-induced kidney injury (DIKI) accounts for 8 to 60% of episodes of acute kidney injury (AKI) among hospital patients. Early DIKI detection and timely adjustment of therapy will help reduce the kidney injury incidence and mortality. The aim of the study was to analyse scientific literature on the biomarkers used in DIKI diagnosis. The study revealed that the use of such kidney damage markers as serum creatinine, urinary output, urea nitrogen, sodium excretion, urinary sediment microscopy is limited because they do not give a full picture of the kidney injury degree and progression and do not allow for early AKI diagnosis. It was demonstrated that some of the most promising biomarkers are KIM-1, L-FABP, NAG, NGAL, cystatin C, clusterin, β2-microglobulin, МСР-1, IGFBP7, and TIMP-2. However, recommendations for determination of these biomarkers’ urine or blood concentrations for AKI diagnosis are somewhat preliminary, because there have been insufficient clinical and preclinical studies to establish validity of such tests. No precise algorithms based on determination of the biomarkers levels in urea and/or blood serum have been developed for AKI risk assessment, diagnosis, monitoring, and treatment. Thus, further research is necessary to investigate different AKI biomarkers and improve experimental models (both in vivo and in vitro), which will support assessment of potential nephrotoxic properties of existing and new medicinal products
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