Multicore liquid perfluorocarbon-loaded multimodal nanoparticles for stable ultrasound and ¹⁹ F MRI applied to in vivo cell tracking

Ultrasound is the most commonly used clinical imaging modality. However, in applications requiring cell-labeling, the large size and short active lifetime of ultrasound contrast agents limit their longitudinal use. Here, 100 nm radius, clinically applicable, polymeric nanoparticles containing a liquid perfluorocarbon, which enhance ultrasound contrast during repeated ultrasound imaging over the course of at least 48 h, are described. The perfluorocarbon enables monitoring the nanoparticles with quantitative 19 F magnetic resonance imaging, making these particles effective multimodal imaging agents. Unlike typical core–shell perfluorocarbon-based ultrasound contrast agents, these nanoparticles have an atypical fractal internal structure. The nonvaporizing highly hydrophobic perfluorocarbon forms multiple cores within the polymeric matrix and is, surprisingly, hydrated with water, as determined from small-angle neutron scattering and nuclear magnetic resonance spectroscopy. Finally, the nanoparticles are used to image therapeutic dendritic cells with ultrasound in vivo, as well as with 19 F MRI and fluorescence imaging, demonstrating their potential for long-term in vivo multimodal imaging. </p

A comprehensive candidate gene approach identifies genetic variation associated with osteosarcoma

<p>Abstract</p> <p>Background</p> <p>Osteosarcoma (OS) is a bone malignancy which occurs primarily in adolescents. Since it occurs during a period of rapid growth, genes important in bone formation and growth are plausible modifiers of risk. Genes involved in DNA repair and ribosomal function may contribute to OS pathogenesis, because they maintain the integrity of critical cellular processes. We evaluated these hypotheses in an OS association study of genes from growth/hormone, bone formation, DNA repair, and ribosomal pathways.</p> <p>Methods</p> <p>We evaluated 4836 tag-SNPs across 255 candidate genes in 96 OS cases and 1426 controls. Logistic regression models were used to estimate the odds ratios (OR) and 95% confidence intervals (CI).</p> <p>Results</p> <p>Twelve SNPs in growth or DNA repair genes were significantly associated with OS after Bonferroni correction. Four SNPs in the DNA repair gene <it>FANCM </it>(ORs 1.9-2.0, <it>P </it>= 0.003-0.004) and 2 SNPs downstream of the growth hormone gene <it>GH1 </it>(OR 1.6, <it>P </it>= 0.002; OR 0.5, <it>P </it>= 0.0009) were significantly associated with OS. One SNP in the region of each of the following genes was significant: <it>MDM2</it>, <it>MPG</it>, <it>FGF2</it>, <it>FGFR3</it>, <it>GNRH2</it>, and <it>IGF1</it>.</p> <p>Conclusions</p> <p>Our results suggest that several SNPs in biologically plausible pathways are associated with OS. Larger studies are required to confirm our findings.</p

Guidelines for the use and interpretation of assays for monitoring autophagy (3rd edition)

In 2008 we published the first set of guidelines for standardizing research in autophagy. Since then, research on this topic has continued to accelerate, and many new scientists have entered the field. Our knowledge base and relevant new technologies have also been expanding. Accordingly, it is important to update these guidelines for monitoring autophagy in different organisms. Various reviews have described the range of assays that have been used for this purpose. Nevertheless, there continues to be confusion regarding acceptable methods to measure autophagy, especially in multicellular eukaryotes. For example, a key point that needs to be emphasized is that there is a difference between measurements that monitor the numbers or volume of autophagic elements (e.g., autophagosomes or autolysosomes) at any stage of the autophagic process versus those that measure fl ux through the autophagy pathway (i.e., the complete process including the amount and rate of cargo sequestered and degraded). In particular, a block in macroautophagy that results in autophagosome accumulation must be differentiated from stimuli that increase autophagic activity, defi ned as increased autophagy induction coupled with increased delivery to, and degradation within, lysosomes (inmost higher eukaryotes and some protists such as Dictyostelium ) or the vacuole (in plants and fungi). In other words, it is especially important that investigators new to the fi eld understand that the appearance of more autophagosomes does not necessarily equate with more autophagy. In fact, in many cases, autophagosomes accumulate because of a block in trafficking to lysosomes without a concomitant change in autophagosome biogenesis, whereas an increase in autolysosomes may reflect a reduction in degradative activity. It is worth emphasizing here that lysosomal digestion is a stage of autophagy and evaluating its competence is a crucial part of the evaluation of autophagic flux, or complete autophagy. Here, we present a set of guidelines for the selection and interpretation of methods for use by investigators who aim to examine macroautophagy and related processes, as well as for reviewers who need to provide realistic and reasonable critiques of papers that are focused on these processes. These guidelines are not meant to be a formulaic set of rules, because the appropriate assays depend in part on the question being asked and the system being used. In addition, we emphasize that no individual assay is guaranteed to be the most appropriate one in every situation, and we strongly recommend the use of multiple assays to monitor autophagy. Along these lines, because of the potential for pleiotropic effects due to blocking autophagy through genetic manipulation it is imperative to delete or knock down more than one autophagy-related gene. In addition, some individual Atg proteins, or groups of proteins, are involved in other cellular pathways so not all Atg proteins can be used as a specific marker for an autophagic process. In these guidelines, we consider these various methods of assessing autophagy and what information can, or cannot, be obtained from them. Finally, by discussing the merits and limits of particular autophagy assays, we hope to encourage technical innovation in the field

Poly-lactic acid nanoparticles (PLA-NP) promote physiological modifications in lung epithelial cells and are internalized by clathrin-coated pits and lipid rafts

BackgroundPoly-lactic acid nanoparticles (PLA-NP) are a type of polymeric NP, frequently used as nanomedicines, which have advantages over metallic NP such as the ability to maintain therapeutic drug levels for sustained periods of time. Despite PLA-NP being considered biocompatible, data concerning alterations in cellular physiology are scarce.MethodsWe conducted an extensive evaluation of PLA-NP biocompatibility in human lung epithelial A549 cells using high throughput screening and more complex methodologies. These included measurements of cytotoxicity, cell viability, immunomodulatory potential, and effects upon the cells’ proteome. We used non- and green-fluorescent PLA-NP with 63 and 66 nm diameters, respectively. Cells were exposed with concentrations of 2, 20, 100 and 200 µg/mL, for 24, 48 and 72 h, in most experiments. Moreover, possible endocytic mechanisms of internalization of PLA-NP were investigated, such as those involving caveolae, lipid rafts, macropinocytosis and clathrin-coated pits.ResultsCell viability and proliferation were not altered in response to PLA-NP. Multiplex analysis of secreted mediators revealed a low-level reduction of IL-12p70 and vascular epidermal growth factor (VEGF) in response to PLA-NP, while all other mediators assessed were unaffected. However, changes to the cells’ proteome were observed in response to PLA-NP, and, additionally, the cellular stress marker miR155 was found to reduce. In dual exposures of staurosporine (STS) with PLA-NP, PLA-NP enhanced susceptibility to STS-induced cell death. Finally, PLA-NP were rapidly internalized in association with clathrin-coated pits, and, to a lesser extent, with lipid rafts.ConclusionsThese data demonstrate that PLA-NP are internalized and, in general, tolerated by A549 cells, with no cytotoxicity and no secretion of pro-inflammatory mediators. However, PLA-NP exposure may induce modification of biological functions of A549 cells, which should be considered when designing drug delivery systems. Moreover, the pathways of PLA-NP internalization we detected could contribute to the improvement of selective uptake strategies

Public-private partnership as a factor of ensuring economic security

© 2020, Institute of Advanced Scientific Research, Inc.. All rights reserved. The article highlights the role of the Public and Private Partnership (PPP) in ensuring economic security in present day Russia. An attempt has been made to explain the mechanism of replacing the budget funds with private investments in infrastructure projects based on the terms and conditions of the public and private partnership. Under discussion is the trend for slow-down in economic development rates and turning the public infrastructure PPP projects into a most important factor in ensuring economic security. Consideration has been made of the main problems relating to increased supply of infrastructure PPP projects and establishment of the corresponding segment of the financial market aimed at servicing project financing

STUDY OF DISPERSE SYSTEMS OF CeO2 AND CeF3 IN STIFFENED MELTS NaNO3-KNO3 BY METHODS OF SPECTROSCOPY OF DIFFUSE REFLECTANCE AND BY THE CHEMICAL ANALYSIS

Processes of dispersion and solubility of CeO2 and CeF3 in the melts of systems NaNO3-KNO3 which are widely used as medium for synthesis of various oxide materials are investigated. The basis of the mechanism of the specified processes is made by the acid-basic and oxidationreduction reactions between initial substances and saline melt. For identification and definition of oxidation degree of Cerium in interaction products are applied spectroscopy of diffuse reflectance in an UV range of a spectrum and the substantial chemical analysis with use as a reagent of a solution of phosphoric acid. For reduction of influence of own absorption of ions NO3– as the sample of comparison it is used stiffened melt of NaNO3-KNO3. Definition of content of Ce(III) is carried out basing on decrease of intensity of coloring of KMnO4. Content of Ce(IV) is established photometrically on intensity of absorption of a phosphate complex (at high content of Ce(IV)) and on decrease of coloring of methanyl yellow (at low content). The data of spectroscopy of diffuse reflectance specifies in prevalence of Ce(IV) with small admixture of Ce(III) in case of system CeO2-(NaNO3-KNO3) and Ce(III) with admixture of Ce(IV) in case of system CeF3-(NaNO3-KNO3). Because of influence of H3PO4 on oxidation degree of cerium in last system, definition of Ce(III) and Ce(IV) by chemical analysis was not carried out. As for system with CeO2, contents of Ce(IV) by method of the chemical analysis are established at level 8-16%масс., and they are higher at system heat treatment on air in comparison with heat treatment in an inert (He) medium. Some inconsistency in the results received by a method of spectroscopy of diffuse reflectance and the chemical analysis, which reason while up to the end is not established, is observed. The role of the superficial phenomena on border solid state – saline melt - gas in processes of dispersion of CeO2 and CeF3 is shown

ВИВЧЕННЯ ДЕГРАДАЦІЇ НАНОСТРУКТУР У СОЛЬОВОМУ ПЛАВІ EuF2 – NaCl – KCl СПЕКТРОСКОПІЧНИМИ МЕТОДАМИ

Methods of luminescent spectroscopy, spectroscopy of diffuse refl ectance and IR transmittance spectroscopy were used for investigation of process of change of nanostructures of Europium (ІІ) fl uoride in stiffened saline melt NaСl – KСl. Europium (ІІ) fluoride was synthesized by high-temperature solid-phase reaction of EuF3 with elemental Germanium ground and pressed into a tablet. The process of synthesis is accompanied by volatizing of GeF2 at hightemperature annealing of the mixture. Prolonged calcinations result in a yellowish powder with a slight gray tint. IR spectrum and spectrum of diffuse refl ectance notify on the nanostructured product. Dissolution of EuF2 in saline melt is regarded as exchange reaction with one of the components, NaCl and complexion with another one, namely KСl. At rapid crystallization of the molten saline solution multiple centers forming and the stabilization of nano-structures of «core-shell» type are occurred. It is established considerable (almost in 2 times for each week) intensity falling 5d-4f photoluminescence with a maximum at ~430 nanometers. At the same time characteristic changes in a spectra of diffuse refl ectance in an UV range of a spectrum with transition from negative values of Kubelka-Munk function to positive ones, with absorption bands observed at 250, 330 and 410 nanometers. Insignifi cant by intensity peaks in a near IR spectrum at 1800-2300 nanometers testify to the small content of Eu3+ ions in the sample that practically does not change eventually. The mechanism of degradation of the nanostructures in stiffened melt and corresponding kinetic equation of the process are proposed. The degradation process is supposed to be caused by environment factors such as moisture and oxygen of an air and results in the destruction of the stabilizing shells of the nanoparticles.Методами люмінесцентної спектроскопії, спектроскопії дифузного відбиття та ІЧ спектроскопії пропускання досліджено процес зміни наноструктур синтезованого фториду Європію(ІІ) у сольовому плаві NaCl – KCl з часом. Встановлено значне падіння інтенсивності 5d–4f фотолюмінесценції. Водночас спостерігаються характерні зміни з часом у спектрі дифузного відбиття в УФ діапазоні з переходом від негативних значень функції Кубелки-Мунка до позитивних. Спостерігається значне зменшення прозорості плаву та послаблення осциляції на ІЧ спектрах пропускання. Висловлено припущення щодо механізму деградації наноструктур у плаві

RESEARCH OF DEGRADATIONS OF NANOSTRUCTURES IN THE SALINE MELT EuF2 – NaCl – KCl BY SPECTROSCOPIC METHODS

Methods of luminescent spectroscopy, spectroscopy of diffuse refl ectance and IR transmittance spectroscopy were used for investigation of process of change of nanostructures of Europium (ІІ) fl uoride in stiffened saline melt NaСl – KСl. Europium (ІІ) fluoride was synthesized by high-temperature solid-phase reaction of EuF3 with elemental Germanium ground and pressed into a tablet. The process of synthesis is accompanied by volatizing of GeF2 at hightemperature annealing of the mixture. Prolonged calcinations result in a yellowish powder with a slight gray tint. IR spectrum and spectrum of diffuse refl ectance notify on the nanostructured product. Dissolution of EuF2 in saline melt is regarded as exchange reaction with one of the components, NaCl and complexion with another one, namely KСl. At rapid crystallization of the molten saline solution multiple centers forming and the stabilization of nano-structures of «core-shell» type are occurred. It is established considerable (almost in 2 times for each week) intensity falling 5d-4f photoluminescence with a maximum at ~430 nanometers. At the same time characteristic changes in a spectra of diffuse refl ectance in an UV range of a spectrum with transition from negative values of Kubelka-Munk function to positive ones, with absorption bands observed at 250, 330 and 410 nanometers. Insignifi cant by intensity peaks in a near IR spectrum at 1800-2300 nanometers testify to the small content of Eu3+ ions in the sample that practically does not change eventually. The mechanism of degradation of the nanostructures in stiffened melt and corresponding kinetic equation of the process are proposed. The degradation process is supposed to be caused by environment factors such as moisture and oxygen of an air and results in the destruction of the stabilizing shells of the nanoparticles

ВИВЧЕННЯ ДИСПЕРСНИХ СИСТЕМ CeO2 І CeF3 У ЗАСТИГЛИХ ПЛАВАХ NaNO3-KNO3 МЕТОДАМИ СПЕКТРОСКОПІЇ ДИФУЗНОГО ВІДБИТТЯ І ХІМІЧНОГО АНАЛІЗУ

Processes of dispersion and solubility of CeO2 and CeF3 in the melts of systems NaNO3-KNO3 which are widely used as medium for synthesis of various oxide materials are investigated. The basis of the mechanism of the specified processes is made by the acid-basic and oxidationreduction reactions between initial substances and saline melt. For identification and definition of oxidation degree of Cerium in interaction products are applied spectroscopy of diffuse reflectance in an UV range of a spectrum and the substantial chemical analysis with use as a reagent of a solution of phosphoric acid. For reduction of influence of own absorption of ions NO3– as the sample of comparison it is used stiffened melt of NaNO3-KNO3. Definition of content of Ce(III) is carried out basing on decrease of intensity of coloring of KMnO4. Content of Ce(IV) is established photometrically on intensity of absorption of a phosphate complex (at high content of Ce(IV)) and on decrease of coloring of methanyl yellow (at low content). The data of spectroscopy of diffuse reflectance specifies in prevalence of Ce(IV) with small admixture of Ce(III) in case of system CeO2-(NaNO3-KNO3) and Ce(III) with admixture of Ce(IV) in case of system CeF3-(NaNO3-KNO3). Because of influence of H3PO4 on oxidation degree of cerium in last system, definition of Ce(III) and Ce(IV) by chemical analysis was not carried out. As for system with CeO2, contents of Ce(IV) by method of the chemical analysis are established at level 8-16%масс., and they are higher at system heat treatment on air in comparison with heat treatment in an inert (He) medium. Some inconsistency in the results received by a method of spectroscopy of diffuse reflectance and the chemical analysis, which reason while up to the end is not established, is observed. The role of the superficial phenomena on border solid state – saline melt - gas in processes of dispersion of CeO2 and CeF3 is shown.Досліджено процес диспергування й розчинності CeO2 і CeF3 у розплаві системи NaNO3-KNO3. Дані спектроскопії дифузного відбиття в УФ діапазоні спектра вказують на перевагу Ce(IV) у першому випадку й Ce(III) – у другому. Показана важлива роль поверхневих явищ у формуванні дисперсних систем. Розробленим методом речовинного хімічного аналізу підтверджено наявність Ce(IV) (до 16.3 %мас.) з невеликою домішкою (до 0.5 %мас.) Ce(III) у верхній і нижній частинах застиглого сольового плаву системи CeO2 – (NaNO3-KNO3)