Biocompatible dextran-coated gadolinium-doped cerium oxide nanoparticles as MRI contrast agents with high T1 relaxivity and selective cytotoxicity to cancer cells.

Gd-based complexes are widely used as magnetic resonance imaging (MRI) contrast agents. The safety of previously approved contrast agents is questionable and is being re-assessed. The main causes of concern are possible gadolinium deposition in the brain and the development of systemic nephrogenic fibrosis after repeated use of MRI contrasts. Thus, there is an urgent need to develop a new generation of MRI contrasts that are safe and that have high selectivity in tissue accumulation with improved local contrast. Here, we report on a new type of theranostic MRI contrast, namely dextran stabilised, gadolinium doped cerium dioxide nanoparticles. These ultra-small (4-6 nm) Ce0.9Gd0.1O1.95 nanoparticles have been shown to possess excellent colloidal stability and high r1-relaxivity (3.6 mM-1 s-1). They are effectively internalised by human normal and cancer cells and demonstrate dose-dependent selective cytotoxicity to cancer cells.

Ceria-Containing Hybrid Multilayered Microcapsules for Enhanced Cellular Internalisation with High Radioprotection Efficiency.

Cerium oxide nanoparticles (nanoceria) are believed to be the most versatile nanozyme, showing great promise for biomedical applications. At the same time, the controlled intracellular delivery of nanoceria remains an unresolved problem. Here, we have demonstrated the radioprotective effect of polyelectrolyte microcapsules modified with cerium oxide nanoparticles, which provide controlled loading and intracellular release. The optimal (both safe and uptake efficient) concentrations of ceria-containing microcapsules for human mesenchymal stem cells range from 1:10 to 1:20 cell-to-capsules ratio. We have revealed the molecular mechanisms of nanoceria radioprotective action on mesenchymal stem cells by assessing the level of intracellular reactive oxygen species (ROS), as well as by a detailed 96-genes expression analysis, featuring genes responsible for oxidative stress, mitochondrial metabolism, apoptosis, inflammation etc. Hybrid ceria-containing microcapsules have been shown to provide an indirect genoprotective effect, reducing the number of cytogenetic damages in irradiated cells. These findings give new insight into cerium oxide nanoparticles' protective action for living beings against ionising radiation.

Photo-induced toxicity of tungsten oxide photochromic nanoparticles.

We synthesised a new type of photochromic tungsten oxide nanoparticles, analysed their photocatalytic activity and carried out a thorough analysis of their effect on prokaryotic and eukaryotic organisms. Ultrasmall hydrated tungsten oxide nanoparticles were prepared by means of hydrothermal treatment of tungstic acid in the presence of polyvinylpyrrolidone as a template, stabiliser and growth regulator. Tungstic acid was synthesised through an ion-exchange method using sodium tungstate solution and a strongly acidic cation exchange resin. Upon illumination, photochromic nanoparticles of WO3 were shown to increase greatly their toxicity against both bacterial (both gram-positive and gram-negative - P. aeruginosa, E. coli and S. aureus) and mammalian cells (primary mouse embryonic fibroblasts); under the same conditions, fungi (C. albicans) were less sensitive to the action of tungsten oxide nanoparticles. UV irradiation of primary mouse fibroblasts in the presence of WO3 nanoparticles demonstrated a time- and dose-dependent toxic effect, the latter leading to a significant decrease in dehydrogenase activity and an increase in the number of dead cells. WO3 nanoparticles were photocatalytically active under both UV light and even diffused daylight filtered through a window glass, leading to indigo carmine organic dye discolouration. The obtained experimental data not only show good prospects for biomedical applications of tungsten trioxide, but also demonstrate the need for clear control of biosafety when it is used in various household materials and appliances.

[Radioprotectors: History, Trends and Prospects].

The search for ideal protective agents for use in a variety of radiation scenarios has continued for more than six decades. This review describes the history of the major discoveries, shows the chronology of the changes in attitudes, trends and paradigms. The readers are invited to meet with various classes of chemical compounds that have the potential to protect against acute and late effects of ionizing radiation when administered either before or after radiation exposure. The work represents characteristics of radioprotective agents such as a dose reduction factor, time of administration, tissue specificity, toxicity; the mechanisms of their action and practical applications are also described. A separate chapter considers the further development prospects and directions in this field of research.

[Natural purine compounds as radioprotective agents].

Purine compounds xanthosine, caffeine, inosine-5'-monophosphate and guanosine-5'-monophosphate in the concentration range of 0.02-1 mmol/L exhibit antioxidant properties in vitro, significantly reducing the formation of hydrogen peroxide and hydroxyl radicals induced by X-rays in aqueous solutions and preventing the formation of 8-oxoguanine in DNA solutions. These compounds neutralize the long-lived protein radicals in vitro induced by radiation. In vivo they exhibit pronounced radiotherapeutic properties, increasing the survival rate of mice up to 50% by intraperitoneal injection (45 mg/kg) after the exposure to a lethal dose of 7 Gy. The tested compounds stimulate hemopoiesis, increasing the number of white blood cells and platelets in the peripheral blood of animals in postradiation period, as well as radiation recovery of DNA damage when administered both before and after irradiation. These purine compounds can be considered as potentially promising preventive and therapeutic agents to reduce the risk of the pathological effects of ionizing radiation on the body of mammals.

[An automated method of measuring the area of contrasted bronchi]. / Avtomatizirovannaia metodika izmereniia ploshchadi konstrastirovannykh bronkhov.

An automated method for measuring the area of the contrasted bronchi is described. The method involves two research stages. The first one consists of routine bronchography provided to patients suffering from pulmonary diseases according to indications. The second stage is reduced to the digital treatment of the bronchograms to measure the area of the contrasted bronchi. The method is used for the diagnosis of functional bronchial disorders. The bronchial area was measured on the bronchograms taken at the height of inspiration and expiration. Using the data obtained and the appropriate formula, the so called integral coefficient of bronchial constriction was calculated. It allows functional disorders of bronchial patency to be diagnosed and a quantitative expression of that pathology to be evaluated.

[Methodology of digital processing of bronchograms]. / Methodik der digitalen Verarbeitung von Bronchogrammen.

A new roentgenologic method for the digital processing of bronchograms and bronchozonograms is described. It has several advantages compared with methods from coherent optics. It provides improved sharpness and contour visibility of the contrasted bronchi and their details by shading correction and alternative positive or negative display mode and therefore improved image quality compared with conventional bronchograms and bronchozonograms. The accuracy of measurements of bronchial lumina and the evaluation of bronchial patency is significantly improved.

[A method of digital processing of bronchograms]. / Metodika tsifrovoi obrabotki bronkhogramm.

Digital bronchogram processing is described as a new method in roentgenology. The aim of this method is to improve the visibility of the single morphological detail inside the bronchi lumens and to make the image of the contrast bronchi more easily and clearly seen. It will ease the procedure of measuring the diameters of the respiratory ways and will help to get more accurate datum of bronchi lumens in cases with chronic bronchitis. Digitization results in improving visibility of the single morphological changes in the bronchi lumens and makes the controls of the contrast bronchi more clear and distinct, in this way it helps greatly in measuring diameters of bronchi. Ordinary bronchograms, bronchosonograms, bronchotomograms, and coherent-optical bronchograms were taken as comparison reference information. According to the investigated parameters, digital processing outdoes the above mentioned x-ray methods of investigation.

[X-ray diagnosis of disturbed bronchial permeability in chronic bronchitis]. / Rentgenodiagnostika narushenii bronkhial'noi prokhodimosti pri khronicheskom bronkhite.

The authors presented clinical and x-ray findings of combined investigation of 94 patients with chronic bronchitis. X-ray symptoms of disturbed bronchial permeability (DBP) in this pathology were studied. Bronchograms, bronchosonograms performed in different phases of respiration using broncholytic drugs, video tape recording, coherent-optic processing of bronchograms, and a method of digital processing of bronchograms proposed by the authors were employed. The importance of x-ray examination in the diagnosis of DBP was shown. The classification, nature, site and spreading of DBP were described. X-ray findings were compared with clinical and laboratory findings.

[The x-ray diagnosis of the functional disorder of bronchial patency in chronic bronchitis]. / Rentgenodiagnostika funktsional'nogo narusheniia bronkhial'noi prokhodimosti pri khronicheskom bronkhite.

The aim of the study was to investigate functional impairments of bronchial patency in chronic bronchitis. Various up-to-date roentgenological procedures were used. Data on complex clinicoroentgenological examination of 94 patients with chronic bronchitis are presented. Bronchograms and bronchial zonograms reflecting various respiration phases, video recording on magnetic tape with using broncholytics and a new procedure of bronchogram digital processing developed by the authors were used to solve the problems. Classification, frequency, localization and nature of functional impairments of bronchial patency in chronic bronchitis are described. The role of x-ray examination in diagnosis of functional impairment of bronchial patency was shown.