Lactose-Functionalized Carbosilane Glycodendrimers Are Highly Potent Multivalent Ligands for Galectin-9 Binding: Increased Glycan Affinity to Galectins Correlates with Aggregation Behavior

Galectins, the glycan binding proteins, and their respective carbohydrate ligands represent a unique fundamental regulatory network modulating a plethora of biological processes. The advances in galectin-targeted therapy must be based on a deep understanding of the mechanism of ligand-protein recognition. Carbosilane dendrimers, the well-defined and finely tunable nanoscaffolds with low toxicity, are promising for multivalent carbohydrate ligand presentation to target galectin receptors. The study discloses a synthetic method for two types of lactose-functionalized carbosilane glycodendrimers (Lac-CS-DDMs). Furthermore, we report their outstanding, dendritic effect-driven affinity to tandem-type galectins, especially Gal-9. In the enzyme-linked immunosorbent assay, the affinity of the third-generation multivalent dendritic ligand bearing 32 lactose units to Gal-9 reached nanomolar values (IC50 = 970 nM), being a 1400-fold more effective inhibitor than monovalent lactose for this protein. This demonstrates a game-changing impact of multivalent presentation on the inhibitory effect of a ligand as simple as lactose. Moreover, using DLS hydrodynamic diameter measurements, we correlated the increased affinity of the glycodendrimer ligands to Gal-3 and Gal-8 but especially to Gal-9 with the formation of relatively uniform and stable galectin/Lac-CS-DDM aggregates.

Biodistribution and toxicity assessment of methoxyphenyl phosphonium carbosilane dendrimers in 2D and 3D cell cultures of human cancer cells and zebrafish embryos

The consideration of human and environmental exposure to dendrimers, including cytotoxicity, acute toxicity, and cell and tissue accumulation, is essential due to their significant potential for various biomedical applications. This study aimed to evaluate the biodistribution and toxicity of a novel methoxyphenyl phosphonium carbosilane dendrimer, a potential mitochondria-targeting vector for cancer therapeutics, in 2D and 3D cancer cell cultures and zebrafish embryos. We assessed its cytotoxicity (via MTT, ATP, and Spheroid growth inhibition assays) and cellular biodistribution. The dendrimer cytotoxicity was higher in cancer cells, likely due to its specific targeting to the mitochondrial compartment. In vivo studies using zebrafish demonstrated dendrimer distribution within the vascular and gastrointestinal systems, indicating a biodistribution profile that may be beneficial for systemic therapeutic delivery strategies. The methoxyphenyl phosphonium carbosilane dendrimer shows promise for applications in cancer cell delivery, but additional studies are required to confirm these findings using alternative labelling methods and more physiologically relevant models. Our results contribute to the growing body of evidence supporting the potential of carbosilane dendrimers as vectors for cancer therapeutics.

RADON-PRONE AREAS IN SLOVAKIA PREDICTED BY RESCALED RADON POTENTIAL MAPS

Several scientific studies have shown that high content of radon in the soil environment can be a precursor of increased indoor radon levels. Inhabited areas where elevated indoor radon concentration appears for natural (geogenic) reasons are commonly referred to as radon-prone areas. In this study, radon-prone areas in the Slovak Republic were predicted on the basis of radon potential maps after its specific rescaling. In total, 99 municipalities have been identified in Slovakia where the annual average indoor radon concentration is expected to exceed the reference level of 300 Bq m-3; five of those are even expected to exceed 1000 Bq m-3. In these municipalities it is then required to conduct a survey of indoor radon measurements. Compared with a nationwide survey, the proposed approach of searching for houses with potentially high radon exposure is more efficient.

RADON MONITORING IN SELECTED KINDERGARTENS IN SLOVAKIA

In 17 kindergartens in Slovakia indoor radon survey was performed over a period of 1 y. In selected kindergartens also continuous monitoring of indoor radon activity concentration was conducted for ~2 weeks, as well as soil radon measurements. Annual average of indoor radon concentration, measured using track detectors, ranged between 75 and 1810 Bq m-3. Soil radon concentration ranged from 13 to 320 kBq m-3. The relationship between activity concentrations measured in soil air and indoors has a linear character.

EMANATION OF RADON-222 FROM DIFFERENT SOIL TYPES AND SOIL GROUPS

In this paper, we deal with measurement of 222Rn emanation coefficient (Ke) of soils using an accumulation method. We created a database of Ke values of dried soils for various soil types and soil groups, classified by the size of soil particles. For 18 different soil samples we obtained the Ke values in range 0.083-0.234. The analysis of radon emanation dependence on moisture for seven of these samples shows two different trends which were related to soil texture (clays or sands). Soils with predominant sandy particles prove weak dependence on moisture and Ke values from minimum value (at zero moisture) do not increase much (max 15% increase on every 5% of moisture), for soils with majority of clayey particles the moisture can affect the Ke more significantly (increase up to 60%).

Carbosilane Glycodendrimers for Anticancer Drug Delivery: Synthetic Route, Characterization, and Biological Effect of Glycodendrimer-Doxorubicin Complexes

The complexity of drug delivery mechanisms calls for the development of new transport system designs. Here, we report a robust synthetic procedure toward stable glycodendrimer (glyco-DDM) series bearing glucose, galactose, and oligo(ethylene glycol)-modified galactose peripheral units. In vitro cytotoxicity assays showed exceptional biocompatibility of the glyco-DDMs. To demonstrate applicability in drug delivery, the anticancer agent doxorubicin (DOX) was encapsulated in the glyco-DDM structure. The anticancer activity of the resulting glyco-DDM/DOX complexes was evaluated on the noncancerous (BJ) and cancerous (MCF-7 and A2780) cell lines, revealing their promising generation- and concentration-dependent effect. The glyco-DDM/DOX complexes show gradual and pH-dependent DOX release profiles. Fluorescence spectra elucidated the encapsulation process. Confocal fluorescence microscopy demonstrated preferential cancer cell internalization of the glyco-DDM/DOX complexes. The conclusions were supported by computer modeling. Overall, our results are consistent with the assumption that novel glyco-DDMs and their drug complexes are very promising in drug delivery and related applications.

Controlled Anchoring of (Phenylureido)sulfonamide-Based Receptor Moieties: An Impact of Binding Site Multiplication on Complexation Properties

The repetition of urea-based binding units within the receptor structure does not only lead to monomer properties multiplication. As confirmed by spectroscopic studies, UV-Vis and ¹H-NMR in classical or competitive titration mode, the attachment to a carrier allocates the active moieties to mutual positions predetermining the function of the whole receptor molecule. Bivalent receptors form self-aggregates. Dendritic receptors with low dihydrogen phosphate loadings offer a cooperative complexation mode associated with a positive dendritic effect. In higher dihydrogen phosphate concentrations, the dendritic branches act independently and the binding mode changes to 1:1 anion: complexation site. Despite the anchoring, the dendritic receptors retain the superior efficiency and selectivity of a monomer, paving the way to recyclable receptors, desirable for economic and ecological reasons.

RESULTS OF LONG-TERM RADON MONITORING IN THE TYPICAL SLOVAK FAMILY HOUSE-A CASE STUDY

This case study provides a view of the behavior of radon in an uninhabited house, the likes of which were built in thousands in Slovakia between 1950 and 1990. In one room of the house that was in contact with the subsoil, an average annual radon activity concentration (RAC) as high as 1088 Bq m-3 was found. A high radon supply to this room from the subsoil was identified in the corner of the room, and this correlated very well with the temperature difference between indoor and outdoor air. In this room, an atypical annual variation of RAC was found, with a maximum in September (1600 Bq m-3). In the other rooms on the ground floor, RACs at the level of 400-500 Bq m-3 were detected. In the rooms on the first floor, RACs of up to ~200 Bq m-3 were found.

ANALYSIS OF TIME SERIES OF RADON ACTIVITY CONCENTRATION IN OUTDOOR AIR AND THEIR RECONSTRUCTION

222Rn (radon) is an ever-present radioactive component of the surface layer of the atmosphere. The knowledge of the shape of radon activity concentration (RAC) time series has several important applications in atmospheric studies. This study presents the results of RAC analysis according to Garzon et al. approach during the years 1991-2009, as well as attempts to reconstruct the shape of composite diurnal RAC cycles using either Garzon et al. original approach or other methods. From this study, it follows that in order to accurately reconstruct the mean diurnal RAC cycles for individual months in our locality (Central European region), the parameters have to be calibrated by local RAC and measured global solar radiation data. The original Garzon et al. approach underestimates the amplitude of mean diurnal RAC cycles during April-August by up to 10%, and overestimates the amplitude during September-March by up to 25%.

DEVELOPMENT OF 222RN IN AIR SECONDARY STANDARD IN THE SLOVAK REPUBLIC

Slovak Institute of Metrology received in 2016 funding for realisation of a set up of a radon chamber with AlphaGUARD as a secondary standard of 222Rn in air as one part of the project. This secondary standard will serve to provide the traceability for laboratories that deal with 222Rn measurements in environmental samples. This project is a response to the European Union legislation and provides metrological support for the development and implementation of the national radon action plan, which the member states of the European Union are committed to fulfil in accordance with Council Directive 2013/59/Euratom. During development of the radon chamber, the determination of its basic technical parameters, such as the exact determination of the container volume and the area of the inner walls of the radon chamber, many tightness tests of the chamber, the definition of homogeneous radon atmosphere parameters and bilateral comparisons, were realised.

RADON ACTIVITY CONCENTRATION IN WATERS OF SPRINGS IN SELECTED AREAS OF WESTERN SLOVAKIA

This paper presents the results of measurements of radon activity concentration (RAC) in spring waters and natural wells in three mountains of Slovakia (Strážov Mountains, Považský Inovec and Little Carpathians). These mountains provide drinking water for inhabitants of surrounding towns and villages. Little Carpathians is the most seismically active area in Slovakia. Považský Inovec, where 2 out of 11 uranium deposits of Slovakia are located, is interesting due to increased uranium mineralization. We have collected samples from more than 170 natural water sources, many of which exceed the guide value of 100 Bq l-1, with a maximum value of 274 Bq l-1. The median of these data (15 Bq l-1) is also higher than the national median in groundwater (11.6 Bq l-1). From the obtained data, we have created maps representing RAC of groundwaters for the whole territory. These maps were also compared with the geological maps.

VARIATION OF RADON ACTIVITY CONCENTRATION IN SELECTED KINDERGARTENS IN SLOVAKIA

Radon measurements were carried out in four kindergartens in Slovakia. RSKS detectors (Radosys Ltd., Hungary) and RamaRn (SUJCHBO, Czech Republic) were used for integral measurement in indoor air. AlphaGUARD (Saphymo, Germany) and TERA system (Tesla, Czech Republic) were used for continual measurement in indoor air. An annual variation with a maximum during the summer holidays was observed. Daily variation strongly depended on the ventilation of rooms. The average radon activity concentration per unit of time calculated from integral measurements was higher than that calculated for working time only.

DEVELOPMENT AND TESTING OF DEVICES FOR CONTINUOUS MONITORING OF RADON ACTIVITY CONCENTRATION IN WATERS

Continuous radon measurement in waters is an appropriate tool for the study of its variations as well as for the clarification and understanding of the factors that cause these changes. In addition, sudden changes in radon activity concentration (RAC) in groundwater can be used to identify geodynamic activities and earthquake predictions. In this paper, two measuring systems for continuous monitoring of RAC in waters are presented and tested. One of them was designed for water sources with a high yield; the second one operates with a constant volume of a sample using a different method of 222Rn release from water. We present our first laboratory tests of continuous measurement of RAC in tap waters as well as the variations of RAC observed during a week.

Carbosilane dendrimers with phosphonium terminal groups are low toxic non-viral transfection vectors for siRNA cell delivery

Non-viral gene delivery vectors studied in the gene therapy applications are often designed with the cationic nitrogen containing groups necessary for binding and cell release of nucleic acids. Disadvantage is a relatively high toxicity which restricts the in vivo use of such nanoparticles. Here we show, that the 3rd generation carbosilane dendrimers possessing (trimethyl)phosphonium (PMe₃) groups on their periphery were able to effectively deliver the functional siRNA into the cells (B14, Cricetulus griseus), release it into the cytosol and finally to achieve up to 40% gene silencing of targeted gene (glyceraldehyde-3-phosphate dehydrogenase (GAPDH)) with the comparable or, in some cases, even better effectivity as their ammonium counterparts. Moreover, such cationic dendrimers show relatively low in vivo toxicity as compared to their ammonium analogues when analyzed by standard fish embryo test (FET) on Danio rerio in vivo model, with LD₅₀ = 6.26 µM after 48 h of incubation. This is more than 10-fold improvement as compared to published values for various other types of cationic dendrimers. We discuss the potential of further increase of the transfection efficiency, endosomal escape and decrease of toxicity of such non-viral vectors, based on the systematic screening of different types of substituents on central phosphonium atom.

Premature ovarian failure

Premature ovarian failure is a heterogeneous disease that brings about several health risks. We must consider that the use of contraception in adolescent girls can mask this disease for a long time. Assisted reproductive technology has brought hope to women with premature ovarian failure to have their own child. Substitution of hormonal deficiency is important for eliminating unpleasant feelings associated with premature ovarian failure as well as for reducing the risk of late effects. Keywords: premature ovarian failure, hypergonadotropic hypogonadism, amenorrhea, gonadal dysgenesis, cryopreservation.

ESI-TOF mass spectrometry of cationic carbosilane dendrimers: A potent tool for characterization of structural defects

Macromolecular polyelectrolytes are gaining considerable attention for the application in medicine that implies their detailed characterization. We have successfully applied electrospray ionization mass spectrometry (ESI MS) to the analysis of defects in the structure of three generations of polycationic carbosilane dendrimers bearing series of quarternary phosphonium groups at their periphery. Besides expected defects caused by incomplete conversion of particular reaction steps during the synthesis of dendritic scaffold and subsequent peripheral functionalization, also, several products of side reactions were observed together with defects created in the course of measurement (particularly ion exchange products). Defective molecules can be to some extent separated by means of gel permeation chromatography that proves that they are not products of in source fragmentation processes. Within the reaction sequence used for the synthesis of dendrimers under study, hydrosilylation was the source of most defects; the effectivity of quarternization depends on the type of phosphine. Results confirm high sensitivity of ESI MS towards defects, stability of the carbosilane skeleton towards fragmentation under the conditions of ESI ionization, and capability to detect both lower- and higher-molecular weight impurities arising from the synthetic sequence in the same m/z range as the target dendrimer, thus providing valuable view of the polydispersity.

On the relation between outdoor 222Rn and atmospheric stability determined by a modified Turner method

In practice, information about atmospheric stability is often obtained from discrete stability classes determined from routine meteorological observations. However, changing concentrations of the radioactive gas ²²²Rn present in the atmosphere are also considered a good indicator of vertical dispersion and atmospheric stability. A complex, in-depth analysis between these different approaches of atmospheric stability assessment has not been performed so far, and was the main motivation behind this study. The study presents atmospheric radon data measured in Bratislava (Slovakia) and stability indexes (SI) calculated according to a modified Turner method during a period of one year. Basic features of the diurnal and seasonal variations of these variables are discussed. It was found that the time series of radon activity concentration (RAC) lags approximately 5 h behind that of the Turner stability classes adjusted for temperate climate regions. Various time lags were also identified between RAC and meteorological variables used to determine the stability classes. Evaluation of seasonal trends revealed a low variability of mean monthly values of stability classes compared to the variability of mean monthly values of RAC. Another notable difference between RAC and stability indexes was found - while the stability index can both increase and decrease with wind speed, concentration of outdoor radon was never observed to increase with increasing wind speed. In spite of the mentioned discrepancies, the time series of RAC and SI are generally in a good agreement. This is especially true if one compares the deviations of RAC and SI from their mean daily values, when the differences in their seasonal variability are eliminated. Deviations of RAC can be used to calculate diurnal variations of stability indexes. Analysis of a complete year of data also revealed a roughly linear relationship between average values of RAC and calculated stability indexes, because in large datasets random processes tend to cancel each other out.

Phosphonium carbosilane dendrimers - interaction with a simple biological membrane model

The influence of three generations of five different phosphonium carbosilane dendrimers and one ammonium carbosilane dendrimer as a reference (PMe3, PBu3, P(Et2)2(CH2)3OH, PPh3, P(MeOPh)3 and NMe3, peripheral functional groups) on dimyristoylphosphatidylcholine (DMPC) or a lipid mixture dimyristoylphosphatidylcholine/dimyristoylphosphatidylglycerol (DMPC/DMPG) of liposomes was studied by fluorescence polarization measurements and differential scanning calorimetry. All types of dendrimers interacted with neutral as well as negatively charged liposomes, but the strength and observed influence were different. Concentration, type of peripheral functional group modification and dendrimer generation were the main factors influencing the interaction. Generally, weak interactions as well as destabilization of the lipid membranes at low concentrations, regardless of liposome type, were observed in the case of DmPMe3, DmNMe3, DmPBu3 and DmP(Et2)2(CH2)3OH. Dendrimers with PPh3 and P(MeOPh)3 peripheral functional groups interacted much more strongly and increased the rigidity of liposomes. Electrostatic interactions, the hydrophobicity of substituents and charge shielding on the peripheral phosphonium group are important factors in the interaction. We suggest that, among the other types of dendrimers, the dendrimer with the P(MeOPh)3 peripheral functional group is a highly promising candidate for the design of a drug delivery system due to its positive charge, efficient interaction with lipidic membranes and low cytotoxicity.

Organoclays with carbosilane dendrimers containing ammonium or phosphonium groups

New composite materials could reveal attractive capabilities and favourable properties.

Preliminary Results of Radon Survey in the Kindergartens of V4 Countries

The measurements of radon concentration were carried out in kindergartens of V4 countries (Hungary, Poland and Slovakia). RSKS detectors (Radosys Ltd., Hungary) were used for integrating measurement in indoor air. In total, 67 rooms in 20 kindergartens were measured. The survey was carried out in two periods from October 2015 to March 2016. The results show that radon concentration is less than 300 Bq m-3 in approximately 86.0% of cases in the first period and in 82.1% of cases in second period. However, rooms in kindergartens with radon concentration exceeding 1000 Bq m-3 were found in Slovakia.

Long-term variations of radionuclides in the Bratislava air

Variations of aerosol radionuclides (2001-2015) in the ground-level air in Bratislava (Slovakia) showed ⁷Be maxima in spring/early summer and minima in winter, however, an inverse trend was observed for ²¹⁰Pb, ¹³⁷Cs and ⁴⁰K. A decreasing amplitude and splitting of summer maxima for ⁷Be in the last years has been found. A temporal behavior of the ⁷Be/²¹⁰Pb activity ratio showed higher levels during warm seasons due to vertical convection of air masses from higher altitudes. The ¹³⁷Cs activity concentration in the surface air between 2003 and 2010 was decreasing with an effective half-life of 1.9 ± 0.3 years. The yearly average ¹³⁷Cs concentrations during 2009-2014 were almost constant, disturbed only by the Fukushima accident in 2011. The increased atmospheric ¹³⁷Cs and ⁴⁰K levels observed during the autumn-winter season may be due to surface soil resuspension, biomass burning and radionuclide transport by winds. Seasonal variations of ²²²Rn activity concentrations were found with maxima at the end of autumn and in winter, and minima in spring. The variability of the average annual course of ²²²Rn has been larger than that of ²¹⁰Pb. The ²¹⁰Pb/²²²Rn activity ratio was highest at the end of winter and in the spring, while from June to December remained nearly constant. More intensive atmospheric mixing in spring months caused a decrease in the ²²²Rn activity concentration, while the aerosol component of the atmosphere has been affected mainly during the autumn and winter seasons. The mean residence time of aerosols in the atmosphere was calculated using the ²¹⁰Pb/²²²Rn method to be 4.5 ± 0.9 days.

Phosphonium carbosilane dendrimers for biomedical applications – synthesis, characterization and cytotoxicity evaluation

Phosphonium carbosilane dendrimers could represent an alternative to ammonium ones in gene therapy applications with high potential of mitochondrial targeting.

Synthesis and characterization of carbosilane dendrimer–sodium montmorillonite clay nanocomposites. Experimental and theoretical studies

Novel organic/inorganic hybrid materials with carbosilane fillers were developed.

Solubilization of PCBs by Surfactant Solution: Minimization of Partitioning Loss of Surfactant

Studies of solubilization of organic contaminants by surfactants are complicated by the fact that the effective surfactant concentration is decreased by partitioning into the organic phase. This paper introduces an experimental setup for surfactant solubilization where the partitioning loss of surfactants is minimized. Using this setup, two anionic (sodium dodecyl sulphate and Spolapon AOS 146) and one nonionic surfactant (Novanik 0633 A) were compared. When comparing solubilization efficacies expressed as multiples of the critical micelle concentration, the two anionic surfactants were able to solubilize a higher amount of polychlorinated biphenyls. For lower surfactant concentrations, solubilization efficacies were similar for all surfactants. However, it is necessary to take into account that the critical micelle concentration of the nonionic surfactant is considerably lower.

[Nontuberculous mycobacteria and incidence of mycobacterioses in Prague in 1999-2004]

OBJECTIVE

To analyze the incidence of nontuberculous mycobacteria detected in Prague patients in 1999-2004 as either single findings suggestive of clinical insignificance or repetitive findings suggestive of mycobacteriosis when reported together with the corresponding organ damage and symptomatology.

MATERIAL AND METHODS

Nontuberculous mycobacteria were isolated and identified according to the Czech recommended methods for mycobacterial diagnosis in two Prague laboratories. The determined incidence rates of Mycobacterium (M.) kansasii, M. avium complex (MAC) and M. xenopi were compared with the respective nationwide rates and those of other nontuberculous bacteria, M. tuberculosis and M. bovis. The data on cases of mycobacterioses reported within the Czech Registry of Tuberculosis were provided by the Institute of Health Information and Statistics of the Czech Republic.

RESULTS

In 1999-2004, the annual incidence rates of nontuberculous mycobacteria detected in Prague patients ranged between 169-139 and accounted for 13-25% of the totals of isolated mycobacteria including M. tuberculosis and M. bovis. Over this period, M. kansasii, MAC and M. xenopi were detected in 45, 76 and 43 patients, respectively. The single to repetitive detection ratio was the highest for M. kansasii (1:1.6), followed by MAC (1:1.8) and M. xenopi (1:2.3). Most male excretors were from higher age categories (median of 58-73 years) while the median age of female excretors ranged between 41 and 75 years. As many as 47 cases of mycobacterioses caused by the following agents: M. kansasii (20 cases), MAC (17 cases), M. xenopi (6 cases) and other nontuberculous mycobacteria (4 cases), were reported to the National Registry of Tuberculosis over the study period.

CONCLUSIONS

Detection and identification of nontuberculous mycobacteria have become part of diagnostic routine of mycobacteriological laboratories. Compared to conventional tuberculous mycobacteria, detection of nontuberculous mycobacteria often requires the use of different and more cumbersome procedures such as incubation at preferential temperatures, longer incubation for detection of growth in primary cultures, species specific culture media, etc.. More skills and experience are needed for the use of automated detection systems and molecular biological techniques for species identification and interpretation of results. Regular consultations with clinical and outpatient physicians are crucial for the assessment of pathogenetic potential of nontuberculous mycobacteria.

Immunodiabetes in rabbits

The changes of basal glycemia and of that during the glucose and insulin tolerance tests as well as of the production of hemagglutinating antibodies in rabbits immunized with crystalline insulin (CI), chromatographically purified insulin (CPI) and waste products of the chromatographic purification of insulin (WP), both with and without complete Freund's adjuvant (CFA) were studied. Following immunization with CI and its components the glycemia increased characteristically and the course of glucose and insulin tolerance tests was changed. The peak levels of antibodies were found following immunization with WP, while the lowest ones appeared following the application of CPI. Following the immunization with a mixture of antigens with CFA higher levels of antibodies were usually observed than following the administration of antigens without adjuvant. No association was found between the titers of antibodies and glycemia values. The principal morphological change in immunized animals was found to be a partial degranulation of B-cells, often accompanied by hyperplasia of A-cells. In groups immunized with CI or CPI mixed with CFA we detected even insulitis, which was absent in the other groups. Following immunization with CI mixed with CFA such cells were found whose granules in the ultrastructure showed conspicuous similarity to those of foetal (immature) rabbit B-cells. It was assumed that in insulin immunized rabbits the initial damage of islets was followed, at least in some regions, by reparative processes. This was indicated by the findings of mitosis figures in B-cells as well as by the islet A-cell hyperplasia.