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.

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.

Simulations of the Behaviour of Steel Ferromagnetic Fibres Commonly Used in Concrete in a Magnetic Field

The efficiency of fibre reinforcement in concrete can be drastically increased by orienting the fibres using a magnetic field. This orientation occurs immediately after pouring fresh concrete when the fibres can still move. The technique is most relevant for manufacturing prefabricated elements such as beams or columns. However, the parameters of such a field are not immediately apparent, as they depend on the specific fibre reaction to the magnetic field. In this study, a numerical model was created in ANSYS Maxwell to examine the mechanical torque acting on fibres placed in a magnetic field with varying parameters. The model consists of a single fibre placed between two Helmholtz coils. The simulations were verified with an experimental setup as well as theoretical relationships. Ten different fibre types, both straight and hook-ended, were examined. The developed model can be successfully used to study the behaviour of fibres in a magnetic field. The fibre size plays the most important role together with the magnetic saturation of the fibre material. Multiple fibres show significant interactions.

P–474 Psychosocial aspects of fertility preservation options for young cancer patients in the Czech Republic: a qualitative study

Study question

What is the real accessibility of fertility preservation techniques and its perception by patients in the Czech Republic?

Summary answer

Fertility preservation options are not offered on a routine basis and often are not part of a treatment plan. Patients wish to be adequately informed.

What is known already

Every year, more than 82.000 people in the Czech Republic develop cancer. The incidence of newly diagnosed cancers in individuals in their reproductive age represents 4.4% of all newly diagnosed oncological diseases. Because the prognosis of treatment in this group of patients is very favourable, the priority in treatment is the emphasis on quality of life after surviving. One of the important parameters of quality of life for many people is the ability to reproduce and the possibility of having a genetic bond to their children.

Study design, size, duration

This qualitative study was conducted in 2019 and relied on explorative in-depth semi-structured interviews. Participants were chosen through occasional sampling.

Participants/materials, setting, methods

We interviewed 13 cancer patients/survivors in their reproductive age (aged 21 to 36; 7 females and 6 males); 4 close family members of young cancer patients; and 8 experts from relevant professional fields. Data gathered from semi-structured interviews were analysed by interpretative phenomenological analysis.

Main results and the role of chance

Cancer was perceived as a threat to life and one’s safety. It causes uncertainty and a feeling of loss of control. It also has a negative impact on a self-concept. Loss of fertility was perceived as a “injury of personality”. The possibility of maintaining fertility has increased the subjectively experienced quality of life.

They make decisions under great time pressure, in a mentally demanding situation. They are usually in the early stages of coping with the diagnosis. The main factors that influenced the respondents’ decision were the amount and quality of information, psychological stress and time pressure.

Patients and their families are interested in being informed about the risks that the disease and its treatment pose to their reproductive health. They want to be able to decide whether to undergo any of the fertility protection techniques. They want to keep their future open. It is therefore desirable that, within oncofertility, we focus on the process of passing on information and supporting decision-making on issues of fertility and its protection. A tool that could be a good informational platform may be so-called decision aid – a tool used to inform patients about available treatments, along with potential benefits, risks and costs.

Limitations, reasons for caution

As all qualitative data, our findings cannot be generalized. Selection bias could have occurred because it is likely that those interested and open to sharing participated.

Wider implications of the findings: Oncofertility treatment is highly relevant and should be offered and discussed with all patients in their reproductive age. Addressing fertility preservation options should be a part of cancer treatment plan of all these patients.

Trial registration number

0

A radioligand binding assay for the insulin-like growth factor 2 receptor

Insulin-like growth factors 2 and 1 (IGF2 and IGF1) and insulin are closely related hormones that are responsible for the regulation of metabolic homeostasis, development and growth of the organism. Physiological functions of insulin and IGF1 are relatively well-studied, but information about the role of IGF2 in the body is still sparse. Recent discoveries called attention to emerging functions of IGF2 in the brain, where it could be involved in processes of learning and memory consolidation. It was also proposed that these functions could be mediated by the receptor for IGF2 (IGF2R). Nevertheless, little is known about the mechanism of signal transduction through this receptor. Here we produced His-tagged domain 11 (D11), an IGF2-binding element of IGF2R; we immobilized it on the solid support through a well-defined sandwich, consisting of neutravidin, biotin and synthetic anti-His-tag antibodies. Next, we prepared specifically radiolabeled [125I]-monoiodotyrosyl-Tyr2-IGF2 and optimized a sensitive and robust competitive radioligand binding assay for determination of the nanomolar binding affinities of hormones for D11 of IGF2. The assay will be helpful for the characterization of new IGF2 mutants to study the functions of IGF2R and the development of new compounds for the treatment of neurological disorders.

Polyvalent C-glycomimetics based on l-fucose or d-mannose as potent DC-SIGN antagonists

The C-type lectin DC-SIGN expressed on immature dendritic cells is a promising target for antiviral drug development. Previously, we have demonstrated that mono- and divalent C-glycosides based on d-manno and l-fuco configurations are promising DC-SIGN ligands. Here, we described the convergent synthesis of C-glycoside dendrimers decorated with 4, 6, 9, and 12 α-l-fucopyranosyl units and with 9 and 12 α-d-mannopyranosyl units. Their affinity against DC-SIGN was assessed by surface plasmon resonance (SPR) assays. For comparison, parent O-glycosidic dendrimers were synthesized and tested, as well. A clear increase of both affinity and multivalency effect was observed for C-glycomimetics of both types (mannose and fucose). However, when dodecavalent C-glycosidic dendrimers were compared, there was no difference in affinity regarding the sugar unit (l-fuco, IC₅₀ 17 μM; d-manno, IC₅₀ 12 μM). For the rest of glycodendrimers with l-fucose or d-mannose attached by the O- or C-glycosidic linkage, C-glycosidic dendrimers were significantly more active. These results show that in addition to the expected physiological stability, the biological activity of C-glycoside mimetics is higher in comparison to the corresponding O-glycosides and therefore these glycomimetic multivalent systems represent potentially promising candidates for targeting DC-SIGN.

[Aggressive angiomyxoma - case report]

OBJECTIVE

We present a case report of 47-years old woman with a rare mesenchymal tumor misdiagnosed as a cyst Bartholins gland.

DESIGN

Case report.

SETTING

Department of Gynecology, Hospital Atlas, EUC, in ZlínConclusion: Aggressive angiomyxoma is a rare mesenchymal tumor, which is occuring more in women, affects the vulva, perineum and pelvis. Typical is slowly and infiltrative growth with high-risk of local recurence.

Characterization of total retinoid-like activity of compounds produced by three common phytoplankton species

Phytoplankton can produce various bioactive metabolites, which may affect other organisms in the aquatic environment. This study provides the first information on the total retinoid-like activity associated with both intracellular and extracellular metabolites produced by selected phytoplankton species that could play a role in teratogenic effects and developmental disruption in exposed organisms. The studied species included a coccoid cyanobacteria (Microcystis aeruginosa), a filamentous cyanobacteria (Aphanizomenon gracile) and a green alga (Desmodesmus quadricauda), all of which commonly occur in freshwater bodies in Europe. Methanolic extracts from cellular material and extracellular exudates were prepared from cultures cultivated in two light-intensity variants with five replicates for each species. The retinoid-like activity was evaluated by in vitro assays along with chemical analyses of two potent retinoic acids (all-trans retinoic acid (ATRA) and 9cis-RA). The mean total retinoid-like activity of metabolites produced by the three studied species representing different phytoplankton taxonomic groups ranged from 705 to 5572ng ATRA equivalent/g dry matter corresponding to 0.064-0.234ng ATRA/10⁶ cells. Retinoid-like activity was found in the cellular extracts of all species, while only the extracellular exudates of cyanobacteria exhibited detectable activity (41-1081ng ATRA/L). The greatest extracellular as well as total (extra- and intra- cellular together) retinoid-like activity was detected for Microcystis aeruginosa. The two potent retinoic acids studied were more frequently detected in cellular extracts than in extracellular exudates of all species. Their contribution to observed in vitro effects was relatively low for all tested samples (<10%), indicating a substantial contribution of other retinoid-like compounds to the overall activity. The results indicate possible influence of light intensity and cell density on the production of metabolites with retinoid-like activity and the cyanotoxin microcystin by the studied species. The recalculation of the results per dry weight, water volume, per 10⁶ cells and biovolume enables a direct comparison of the retinoid-like activity distribution between extracts and exudates and the use of the data for risk assessment in water bodies.

Novel metabolites in cyanobacterium Cylindrospermopsis raciborskii with potencies to inhibit gap junctional intercellular communication

Despite intensive research into toxic bloom-forming cyanobacteria, the majority of their metabolites remain unknown. The present study explored in detail a novel bioactivity identified in cyanobacteria, i.e. inhibition of gap junctional intercellular communication (GJIC), a marker of tumor promotion. The extracellular mixture (exudate) of the cyanobacterial strain Cylindrospermopsis raciborskii (SAG 1.97) was fractionated by semi-preparative reversed phase HPLC, and the fractions assessed for their potencies to inhibit GJIC. Two non-polar fractions that significantly inhibited GJIC were further fractionated, tested and analyzed using multiple mass spectrometric methods. Investigations led to the identification of a putative chemical compound (molecular formula C18H34O3, m/z 299.2581 for the [M+H](+) ion) responsible for observed bioactivities. Specific inhibitors of signaling pathways were used to screen for biochemical mechanisms beyond GJIC inhibition, and the results indicate the involvement of ERK1/2 kinases via a mechanism related to the action of epidermal growth factor EGF but clearly distinct from other anthropogenic tumor promoters like polychlorinated biphenyls or polycyclic aromatic hydrocarbons. The chemical and in vitro toxicological characterizations of the newly described metabolite provide important insights into the still poorly understood health impacts of complex toxic cyanobacterial blooms and indicate that currently applied monitoring practices may underestimate actual risks.

Tumor promoting effects of cyanobacterial extracts are potentiated by anthropogenic contaminants--evidence from in vitro study

Inhibition of gap junctional intercellular communication (GJIC) is affiliated with tumor promotion process and it has been employed as an in vitro biomarker for evaluation of tumor promoting effects of chemicals. In the present study we investigated combined effects of anthropogenic environmental contaminants 2,2',4,4',5,5'-hexachlorobiphenyl (PCB 153) and fluoranthene, cyanotoxins microcystin-LR and cylindrospermopsin, and extracts of laboratory cultures of cyanobacteria Aphanizomenon gracile and Cylindrospermopsis raciborskii, on GJIC in the rat liver epithelial cell line WB-F344. Binary mixtures of PCB 153 with fluoranthene and the mixtures of the two cyanobacterial strains elicited simple additive effects on GJIC after 30 min exposure, whereas microcystin-LR and cylindrospermopsin neither inhibited GJIC nor altered effects of PCB 153 or fluoranthene. However, synergistic effects were observed in the cells exposed to binary mixtures of anthropogenic contaminants (PCB 153 or fluoranthene) and cyanobacterial extracts. The synergistic effects were especially pronounced after prolonged (6-24h) co-exposure to fluoranthene and A. gracile extract, when mixture caused nearly complete GJIC inhibition, while none of the individual components caused any downregulation of GJIC at the same concentration and exposure time. The effects of cyanobacterial extracts were independent of microcystin-LR or cylindrospermopsin, which were not detected in cyanobacterial biomass. It provides further evidence on the presence of unknown tumor promoting metabolites in cyanobacteria. Clear potentiation of the GJIC inhibition observed in the mixtures of two anthropogenic contaminants and cyanobacteria highlight the importance of combined toxic effects of chemicals in complex environmental mixtures.

Estrogenic activity in extracts and exudates of cyanobacteria and green algae

Here is presented some of the first information on interactions of compounds produced by cyanobacteria and green algae with estrogen receptor signaling. Estrogenic potency of aqueous extracts and exudates (culture spent media with extracellular products) of seven species of cyanobacteria (10 different laboratory strains) and two algal species were assessed by use of in vitro trans-activation assays. Compounds produced by cyanobacteria and algae, and in particular those excreted from the cells, were estrogenic. Most exudates were estrogenic with potencies expressed at 50% of the maximum response under control of the estrogen receptor ranging from 0.2 to 7.2 ng 17β-estradiol (E(2)) equivalents (EEQ)/L. The greatest estrogenic potency was observed for exudates of Microcystis aerigunosa, a common species that forms water blooms. Aqueous extracts of both green algae, but only one species of cyanobacteria (Aphanizomenon gracile) elicited significant estrogenicity with EEQ ranging from 15 to 280 ng 17β-estradiol (E(2))/g dry weight. Scenedesmus quadricauda exudates and extracts of Aphanizomenon flos-aquae were antagonistic to the ER when coexposed to E(2). The EEQ potency was not correlated with concentrations of cyanotoxins, such as microcystin and cylindrospermopsin, which suggests that the EEQ was comprised of other compounds. The study demonstrates some differences between the estrogenic potency of aqueous extracts prepared from the same species, but of different origin, while the effects of exudates were comparable within species. The observed estrogenic potencies are important namely in relation to the possible mass expansion of cyanobacteria and release of the active compounds into surrounding water.

[A review of radiodiagnosis of inflammations]

Inflammation is a complex reaction of the organism which develops as a response to invasion of an infectious subject or as a response to injury to cells or tissues. Correct and early localization of infection or an inflammatory lesion allows removing the inflammatory cause quickly. Over the recent thirty years, a wide range of radiopharmaceuticals, more or less applicable in scintigraphic imaging of inflammatory and infectious diseases, have been developed. The aim has been to develop new substances that are non-toxic, do not provoke immune reactions, and produce a minimal absorbed radioactive dose. Furthermore, these substances should accumulate significantly in the target tissue (i.e. in inflammation), while the accumulation in non-target tissues should be minimal or the elimination of radiopharmaceuticals from non-target tissues must be quick. The goal is that these substances may also be easily available and inexpensive. Another purpose is to develop such substances that could possess not only sufficient sensitivity but also specificity in relation to certain types of inflammation and infection. The main indications for radionuclide imaging are as follows: inflammatory bowel disease, soft tissue sepsis, predominantly abdominal sepsis, musculoskeletal infection, and fever of unknown origin.

[The Castillo-Morales method in children with orofacial hypotonia]

Recently great attention is paid to hypotonia of the orofacial region because this disorder is a great handicap for mentally normal children. In the submitted paper the authors demonstrate treatment of a girl who suffered from hypotonia of the orofacial region with hypersalivation to the age of four years. After intensive therapy complete normalization of this developmental defect was achieved.

[The effectiveness of psychotherapeutic methods in paedodontics]

The authors divide psychotherapeutis procedures and method influencing the patient's behavior during dental treatment into preventive methods and those facilitating treatment and making treatment possible. At the same time they evaluate their effectiveness in a group of 269 "untreatable patients" with a different intellectual level. They found that these methods were successful in almost half the patients when treating preschool and primary school children.

[Effect of psychotherapy on problem behavior of children and adolescents in stomatological office]

The group of 269 "untreatable patients" aged 3-18 years was followed up for the effectiveness of psychotherapeutical management of problem behavior (in %). The used psychotherapeutical methods appeared to be most effective in individuals attending primary school (81.5%), satisfactory were in patients attending the school with special education (44.8%). No effects of psychotherapy were observed in oligophrenic patients who refused cooperation during the first stomatological treatment.