Research outputs from Pure / Zinātniskās darbības rezultāti no ZDIS Pure

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1,1′-{[3,5-Bis((dodecyloxycarbonyl)-4-phenyl-1,4-dihydropyridine-2,6-diyl]bis(methylene)}bis[4-(anthracen-9-yl)pyridin-1-ium] Dibromide
(2022-09) Ozolins, Reinis; Plotniece, Mara; Pajuste, Karlis; Putralis, Reinis; Pikun, Nadiia; Sobolev, Arkadij; Plotniece, Aiva; Rucins, Martins; Department of Pharmaceutical Chemistry
A synthesis of a cationic moiety and fluorescent moieties containing amphiphilic 1,4-dihydropyridine (1,4-DHP) derivatives was performed starting with the Hantzsch-type cyclization of dodecyl acetoacetate, phenylaldehyde and ammonium acetate. Bromination of the 2,6-dimethyl groups of a parent 1,4-DHP compound, followed by nucleophilic substitution of bromine with 4-(anthracen-9-yl)pyridine, produced the desired 1,1′-{[3,5-bis((dodecyloxycarbonyl)-4-phenyl-1,4-dihydropyridine-2,6-diyl]bis(methylene)}bis[4-(anthracen-9-yl)pyridin-1-ium] dibromide. The obtained target compound was fully characterized by the IR, 1H NMR, 13C NMR and HRMS data. Studies of the self-assembling properties and characterization of the nanoparticles obtained by the ethanol injection method were performed using dynamic light scattering (DLS) measurements. DLS measurement data showed that 1,1′-{[3,5-bis((dodecyloxycarbonyl)-4-phenyl-1,4-dihydropyridine-2,6-diyl]bis(methylene)}bis[4-(anthracen-9-yl)pyridin-1-ium] dibromide produced liposomes that had average diameters of 200 nm when the samples were freshly prepared, and 140 nm after 7 days or 1 month storage. The PDI values of the samples were approximately 0.50 and their zeta-potential values were approximately 41 mV when the samples were freshly prepared, and 33 mV after storage. The obtained nanoparticles were stored at room temperature for one month and remained stable during that period. The mean molecular area of the cationic 1,4-DHP-anthracene hybrid 4 was 118 Å2, while the mean molecular area of the cationic 1,4-DHP 5 without anthracene substituents was only 83 Å2. The photoluminescence quantum yield (PLQY) value for the EtOH solution of the 1,4-DHP derivative 4 was 10.8%, but for the 1,4-DHP derivative 5 it was only 1.8%. These types of compounds could be used as synthetic lipids in the further development of prospective theranostic delivery systems.
1,1′-{[3,5-Bis(dodecyloxycarbonyl)-4-(naphthalen-2-yl)-1,4-dihydropyridine-2,6-diyl]bis(methylene)}bis{4-[(E)-2-(naphthalen-2-yl)vinyl]pyridin-1-ium}dibromide
(2022-09) Rucins, Martins; Kaukulis, Martins; Plotniece, Aiva; Pajuste, Karlis; Pikun, Nadiia; Sobolev, Arkadij
Synthesis of a double-charged cationic amphiphilic 1,4-dihydropyridine derivative with dodecyl ester groups at positions 3 and 5 of the 1,4-DHP ring was performed starting from Hantzsch type cyclization of dodecyl acetoacetate, 2-naphthaldehyde and ammonium acetate. Bromination of this compound followed by nucleophilic substitution of bromine with (E)-4-(2-(naphthalen-2-yl)vinyl)pyridine gave the desired cationic amphiphilic 1,1′-{[3,5-bis(dodecyloxycarbonyl)-4-(naph-thalen-2-yl)-1,4-dihydropyridine-2,6-diyl]bis(methylene)}bis{4-[(E)-2-(naphthalen-2-yl)vinyl]pyridin-1-ium}dibromide. The obtained target compound was fully characterized by IR, UV,1 H-NMR,13 C-NMR, HRMS and microanalysis. The characterization of the cationic 1,4-DHP nanoparticles in an aqueous solution was performed by DLS measurements. The obtained results showed that the compound formed nanoparticles with an average diameter of around 300 nm, a PDI value of around 490 and a zeta-potential of around 20 mV for freshly prepared samples. However, after one week of storage at room temperature, an aggregation of nanoparticles was detected.
Anti-Inflammatory, Anti-Bacterial, and Anti-Fungal Activity of Oligomeric Proanthocyanidins and Extracts Obtained from Lignocellulosic Agricultural Waste
(2023-01-15) Andersone, Anna; Janceva, Sarmite; Lauberte, Līga; Ramata-Stunda, Anna; Nikolajeva, Vizma; Zaharova, Natalija; Rieksts, Gints; Telesheva, Galina; Laboratory of Finished Dosage Forms
It has now been proven that many pathogens that cause infections and inflammation gradually mutate and become resistant to antibiotics. Chemically synthesized drugs treating inflammation most often only affect symptoms, but side effects could lead to the failure of human organs’ functionality. On the other hand, plant-derived natural compounds have a long-term healing effect. It was shown that sea buckthorn (SBT) twigs are a rich source of biologically active compounds, including oligomeric proanthocyanidins (PACs). This study aimed to assess the anti-pathogenic and anti-inflammatory activity of water/ethanol extracts and PACs obtained from the lignocellulosic biomass of eight SBT cultivars. The anti-pathogenic activity of extracts and PACs was studied against pathogenic bacteria Pseudomonas aeruginosa, Staphylococcus aureus, Escherichia coli, Bacillus cereus and fungus Candida albicans in 96-well plates by the two-fold serial broth microdilution method. The anti-bacterial activity of purified PACs was 4 and 10 times higher than for water and water/ethanol extracts, respectively, but the extracts had higher anti-fungal activity. Purified PACs showed the ability to reduce IL-8 and IL-6 secretion from poly-I:C-stimulated peripheral blood mononuclear cells. For the extracts and PACs of SBT cultivar ‘Maria Bruvele’ in the concentration range 0.0313–4.0 mg/mL, no toxic effect was observed.
Antibacterial Activity of Tanacetum vulgare L. Extracts against Clinical Isolates of Bovine Mastitis
(2023-03) Šukele, Renāte; Bārzdiņa, Ance; Koka, Rudīte; Skadins, Ingus; Lauberte, Līga; Brangule, Agnese; Kovalcuka, Liga; Bandere, Dace; Department of Pharmaceutical Chemistry; Red Cross Medical College of Rīga Stradiņš University; Department of Biology and Microbiology; Laboratory of Finished Dosage Forms
A bovine mastitis is an infectious disease, which is usually treated with antibiotics. Alternatively, herbal medicine has been proposed due to bacterial resistance. The aim of this study was to determine the antibacterial activity of the acetonic and ethanolic extracts of dried flowers and leaves of Tanacetum vulgare L. against bovine mastitis-inducing clinical isolates such as Escherichia coli, Streptococcus agalactiae, Streptococcus uberis, Serratia liquefaciens, Staphylococcus aureus, and reference cultures of S. aureus and E. coli. The extracts of T. vulgare showed partial antibacterial activity against tested strains of S. aureus. The MIC and MBC values of a 70% ethanol extract of flowers (MIC = 3.4 mg/mL, MBC = 3.4–6.8 mg/mL) were lower than for the 70% ethanol extract of leaves (MIC = 15.7–31.4 mg/mL, MBC = 62.9–125.9 mg/mL). The flower extracts showed low activity against E. coli (MIC = 53.9 mg/mL, MBC = 53.9–107.8 mg/mL) and S. agalactiae (MIC, MBC = 53.9 mg/mL). T. vulgare leaf extracts had minimal antibacterial effects against Streptococcus strains (MIC = 31.4–62.9 mg/mL, MBC = 53.9–125.9 mg/mL) and Serratia liquefaciens (MIC, MBC = 125.9 mg/mL). However, flower extracts had a higher phenolic content that did not correlate with antibacterial effects. T. vulgare flower and leaf extracts could be combined to obtain broader antibacterial effects.
Antioxidant Status in Patients after Breast Mastopexy and Augmentation
(2024-06-26) Jurševičs, Kirils; Jurševičs, Eduards; Krasiļņikova, Jeļena; Šķesters, Andrejs; Lece, Anna; Skadiņš, Ingus; Department of Doctoral Studies; Department of Human Physiology and Biochemistry; Bioķīmijas zinātniskā laboratorija; Department of Biology and Microbiology
Background and Objectives: Mammary gland surgery has become very common, but there are complications of these operations, including the concept of breast implant illness (BII) in women with silicone gel breast implants (SBI), who suffer from various symptoms such as myalgia, arthralgia, fatigue, fever, dry eyes, or dry mouth. Silicone biomaterials are synthetic polymers that have their own physical and chemical properties and can exert their effect at the site of use and possibly on the general status of the body, causing inflammation and oxidative stress signs. The aim of the study was to examine components of the blood antioxidant system (AOS) of the mastopexy and breast augmentation patients before the operation, on the first post-op day, and 6 months after surgery. Materials and Methods: Healthy breast surgery patients (women aged 31 to 60 years without visible pathologies) were selected for the study and formed 2 groups: breast lift—mastopexy without silicone biomaterials (I group, 30 patients) and breast augmentation using silicone biomaterials (II group, 28 patients). All patients underwent standard preoperative tests. Glutathione peroxidase (GPxSe) and gamma-glutamyl transferase (GGT) in blood, selenium (Se), selenium protein P (SelPP), and total antioxidant status (TAS) in plasma were measured as AOS parameters. The concentration of vitamin D was also determined. A total of 174 blood tests were performed. Results: Overall, there were no differences in both groups in measured antioxidant system indicators over time; neither changes in objective nor subjective status were observed. However, baseline activity of GPxSe was relatively high but restored to normal values 6 months after surgery. In the mastopexy group, GPxSe decreased from 12,961.7 U/L by 18.9% to 10,513.4 U/L, and in the breast augmentation group, from 15,505.0 U/L by 25.1% to 11,265.5 U/L, which is a decrease of 18.9% and 25.1%, respectively. The patients did not note any complaints; other indicators of standard biochemical tests were within normal limits. Conclusions: The two types of surgical interventions, breast mastopexy and augmentation of the mammary glands, do not significantly impact blood AOS and are physiological in nature.
The Association of Plasma Selenium and Selenoprotein P Levels with Depression Severity and Anxiety Symptoms Among Medical Students in Latvia
(2025-01) Brigele, Zanda; Vimba, Paula Marija; Ševčenko, Anastasija; Šķesters, Andrejs; Ancāne, Gunta; Valaine, Laura; Institute of Occupational Safety and Environmental Health; Department of Psychosomatic Medicine and Psychotherapy
Background and Objectives: Oxidative stress has been identified as a key process involved in different diseases, particularly depression. Selenium (Se) protects against oxidative stress, one of the pathogenic mechanisms involved in affective disorders. Selenium is incorporated into antioxidant selenoproteins, such as selenoprotein P, which acts as the main selenium-transport protein in plasma and as an extracellular oxidant defense mechanism. This study aimed to determine whether lower selenium and selenoprotein P levels correlate with high levels of depression and anxiety symptoms. Materials and Methods: The research design was a quantitative cross-sectional study among employed fourth-year medical students at Riga Stradins University in Latvia. The respondents were selected using convenience samples. The symptoms of anxiety were assessed using the Generalized Anxiety Disorder-7 (GAD-7) scale, and the symptoms of depression were assessed using the Patient Health Questionnaire-9 (PHQ-9) scale. Results: A total of 32 respondents participated; 90.6% (n = 29) were female. A significant association was found between selenoprotein P and symptoms of depression (p = 0.006), as well as between selenoprotein P and symptoms of anxiety (p = 0.012). The median selenium level was not significantly lower (p = 0.214) in the study group compared to the control group. Conclusions: There is a statistically significant correlation between selenoprotein P and symptoms of depression and anxiety, and there is a tendency for students with symptoms of depression and anxiety to have lower selenium levels. However, alternative unrecognized oxidative stress mechanisms involved in the development of symptoms of depression and anxiety, involving selenium and selenoprotein P pathways, may exist. Consequently, further research assessing possible alternative pathways and the effect size is required.
Autofluorescence imaging of the skin is an objective non-invasive technique for diagnosing pseudoxanthoma elasticum
(2021) Farkas, Klára; Bozsányi, Szabolcs; Plázár, Dóra; Bánvölgyi, András; Fésűs, Luca; Anker, Pálma; Zakariás, Sára; Lihacova, Ilze; Lihachev, Alexey; Lange, Marta; Arányi, Tamás; Wikonkál, Norbert M.; Medvecz, Márta; Kiss, Norbert
Pseudoxanthoma elasticum (PXE) is a rare multisystemic autosomal recessive connective tissue disease. In most cases, skin manifestations of PXE are the first to develop, followed later by severe ocular and cardiovascular complications. In our present study, in addition to dermoscopy, we introduced novel techniques, autofluorescence (AF) and diffuse reflectance (DR) imaging for the assessment of affected skin sites of five PXE patients. PXE-affected skin areas in most skin sites showed a previously observed pattern upon dermoscopic examination. With the novel imaging, PXE-affected skin lesions displayed high AF intensity. During our measurements, significantly higher mean, minimum and maximum AF intensity values were found in areas of PXE-affected skin when compared to uninvolved skin. Conversely, images acquired with the use of 660 and 940 nm illumination showed no mentionable difference. Our results demonstrate that AF imaging may be used in the in vivo diagnostics and quantification of the severity of the skin lesions of PXE patients. In addition, it is a safe, fast and cost-effective diagnostic method. AF imaging may be also used to objectively monitor the efficacy of the possible novel therapeutic approaches of PXE in the future.
Bi2Se3 Nanostructured Thin Films as Perspective Anodes for Aqueous Rechargeable Lithium-Ion Batteries
(2022-10) Lazarenko, Vitalijs; Rublova, Yelyzaveta; Meija, Raimonds; Andzane, Jana; Voikiva, Vanda; Kons, Artis; Sarakovskis, Anatolijs; Viksna, Arturs; Erts, Donats
In recent years, aqueous rechargeable lithium-ion batteries (ARLIBs) have attracted attention as an alternative technology for electrical storage. One of the perspective battery anode materials for application in ARLIBs is Bi2Se3, which has already shown good perspectives in the application of conventional lithium-ion batteries (LIBs) that use organic electrolytes. In this study, the electrochemical properties of Bi2Se3 thin films with two different layers on the electrode surface—the solid electrolyte interphase (SEI) and the Bi2O3 layer—were investigated. The results of this work show that the formation of the SEI layer on the surface of Bi2Se3 thin films ensures high diffusivity of Li+, high electrochemical stability, and high capacity up to 100 cycles, demonstrating the perspectives of Bi2Se3 as anode material for ARLIBs.
The Biosphere Self-Organization Attractors drive perfect order homeostasis reactions to link bioenergetic with functionally activate oxygen and carbon dioxide molecules
(ICNTC Secretariat, 2021) Kaksis, Āris; Dasdan, Şakar; Department of Human Physiology and Biochemistry
The quantitative studies for oxygen and carbon dioxide functional activity reveal multiply generated Self-Organization Attractors which create and maintain order the homeostasis: water concentration [H2O]=55.3 mol/Liter, pH=7.36, enzyme Carbonic Anhydrase reactivity, air oxygen level 20.95 % O2 [1] , osmolar concentration 0.305 M, ionic strength 0.25 M, temperature 310.15 K degree etc. that make oxygen fire safe and CO2aqua functional active for Life Biochemistry. Air oxygen level 20.95 % O2 [1] dissolute in organism forming arterial concentration [O2aqua] safe for Bioenergetic as Self-Organization Attractor [3] sustaining isooxia. Thermodynamic indicate Biosphere indispensability to reach Self-Organization Attractor values. Destiny is trend to minimum of free energy change in homeostasis. Attractors made functionally active molecules Self-Organize the perfect reactions order in homeostasis. [2,3,4] Deviation from Attractor values disorder the homeostasis. Chaos stop the homeostasis which disappears as extinct from Biosphere.
Can Our Blood Help Ensure Antimicrobial and Anti-Inflammatory Properties in Oral and Maxillofacial Surgery?
(2023-01) Mičko, Lana; Šalma, Ilze; Skadiņš, Ingus; Egle, Karina; Šalms, Ģirts; Dubnika, Arita; Department of Oral and Maxillofacial Surgery and Oral Medicine; Department of Biology and Microbiology
In recent decades, the potential of PRF has been extensively studied. The number of studies about PRF has increased three times since the year 2012, but the full spectrum of its fundamental properties, such as antimicrobial and anti-inflammatory activity, is not clearly described. In oral and maxillofacial surgery, PRF is described in alveolar ridge preservation, orthognathic surgery, cleft lip and palate surgery, maxillary sinus augmentation, and dental implant placement as demonstrating favorable results and its clinical advantages. The structural complexity, inhomogeneous nature, and clotting ability of PRF make its antimicrobial effect evaluation complicated. Nevertheless, most of the used antimicrobial testing methods are based on antibacterial agent diffusion ability in culture media. Because the oral and maxillofacial region is the most frequent area of PRF application, its antimicrobial activity evaluation also prevails in the oral microbiome. PRF’s biological potential is highly dependent on the specific preparation protocol and methodology used; it should be carefully prepared and kept under proper conditions to keep cellular content alive. PRF’s influence on living cells demonstrates a stimulating effect on bone regeneration, and an angiogenetic effect, and it provides anti-inflammatory activity. According to analyzed studies, PRF demonstrated success in oral and maxillofacial surgery in various methods of application. Antibacterial and anti-inflammatory properties were proven by antibacterial activity against different bacterial species, sustained growth factor, sustained release, and cell activity on the material application. Accurately and correctly prepared PRF can ensure antibacterial and anti-inflammatory properties, and it can be a beneficial clinical tool in oral and maxillofacial surgery.
Cantilever-enhanced photoacoustic spectroscopy applied in the research of natural and synthetic calcium phosphate
(2017-04-21) Brangule, Agnese; Gross, K. A.; Stepanova, V.; Department of Human Physiology and Biochemistry
This study demonstrates the significant potential of cantilever-enhanced Fourier transform infrared photoacoustic spectroscopy (FTIR PAS) principles. The improved sensitivity and reproducibility of this method presents a potent tool in the study of biomaterials. The article discusses aspects of the application of cantilever-enhanced FTIR PAS in the research of natural and biological calcium phosphate and the statistical evaluation of the FTIR PAS sampling method. The improved constructions of the FTIR PAS accessory reduce limitations of the conventional capacitive microphone and provide a sensitive tool for samples or processes unreachable by more traditional transmittance methods, or ATR sampling technique. The most common and important applications have been discussed in-depth to show the wide range of problems solved by FTIR PAS.
Circulating miRNAs Expression in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome
(2023-07) Soffritti, Irene; Gravelsina, Sabine; D’Accolti, Maria; Bini, Francesca; Mazziga, Eleonora; Vilmane, Anda; Rasa-Dzelzkaleja, Santa; Nora-Krukle, Zaiga; Krumina, Angelika; Murovska, Modra; Caselli, Elisabetta; Institute of Microbiology and Virology; Department of Infectology
Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is a complex multifactorial disease that causes increasing morbidity worldwide, and many individuals with ME/CFS symptoms remain undiagnosed due to the lack of diagnostic biomarkers. Its etiology is still unknown, but increasing evidence supports a role of herpesviruses (including HHV-6A and HHV-6B) as potential triggers. Interestingly, the infection by these viruses has been reported to impact the expression of microRNAs (miRNAs), short non-coding RNA sequences which have been suggested to be epigenetic factors modulating ME/CFS pathogenic mechanisms. Notably, the presence of circulating miRNAs in plasma has raised the possibility to use them as valuable biomarkers for distinguishing ME/CFS patients from healthy controls. Thus, this study aimed at determining the role of eight miRNAs, which were selected for their previous association with ME/CFS, as potential circulating biomarkers of the disease. Their presence was quantitatively evaluated in plasma from 40 ME/CFS patients and 20 healthy controls by specific Taqman assays, and the results showed that six out of the eight of the selected miRNAs were differently expressed in patients compared to controls; more specifically, five miRNAs were significantly upregulated (miR-127-3p, miR-142-5p, miR-143-3p, miR-150-5p, and miR-448), and one was downmodulated (miR-140-5p). MiRNA levels directly correlated with disease severity, whereas no significant correlations were observed with the plasma levels of seven pro-inflammatory cytokines or with the presence/load of HHV-6A/6B genome, as judged by specific PCR amplification. The results may open the way for further validation of miRNAs as new potential biomarkers in ME/CFS and increase the knowledge of the complex pathways involved in the ME/CFS development.
Comparison of antioxidant activity in various spirulina containing products and factors affecting it
(2023-03-20) Stunda - Zujeva, Agnese; Berele, Megija; Lece, Anna; Šķesters, Andrejs; Bioķīmijas zinātniskā laboratorija; Institute of Occupational Safety and Environmental Health
Spirulina is a popular food supplement known for its high antioxidant activity. Several studies have shown that antioxidant activity fluctuates depending on the combination of ingredients in the food. Fresh spirulina is a growing market trend; however, pure spirulina short shelf life is a strong limitation. This study aims to investigate antioxidant activity of various novel commercial fresh spirulina-containing products and the factors affecting it. Antioxidant activity and total phenolic content of each ingredient and binary combinations of spirulina and apple juices, Japanese quince syrup, or cranberry syrup were measured. Synergic, antagonistic, and additive interactions between samples were determined and expressed using the synergy coefficient. FRAP assay showed apparent synergism of spirulina and all the studied ingredients whereas ABTS and Folin–Ciocalteu methods revealed an antagonistic interaction between spirulina and apple juice. Despite the antagonistic interactions, all the products demonstrated at least the same antioxidant activity as pure fresh spirulina and had longer shelf life than, pointing to their commercial potential.
Comparison of biological markers in aerosol-weighed workplaces
(2019-07-01) Pavlovska, Ilona; Martinsone, Žanna; Ramata-Stunda, Anna; Vanadziņš, Ivars; Mārtiņsone, Inese; Seile, Anita; Institute of Occupational Safety and Environmental Health
Airborne particulates present a potential hazard to health in a variety of indoor workplaces, from offices to the manufacturing floor. Dust and aerosols are two of the most common occupational risk factors in the workplace worldwide. It is very important to understand when it is sufficient to describe dust exposure only by given mass concentration that dust particles could be in the nanosized range in the workplace air even for brief exposures, such as welding aerosols. The main objective was to assess total dust and nanoparticle concentrations in the selected workplaces and to evaluate their impact on workers’ health. This project describes nanoparticle concentrations and their potential impact on workers’ health considering the exposure levels in three workplaces. Industrial and non-industrial environments have been included in the project. The office environment was used as an indicator for the background level of comparison with the metalworking and woodworking industries for measurements of dust particles including the nanoscale particles (> 100 nm). Fraction size of the samples according to a dispersity of > 10 μm, 0.25–10 μm, < 0.25 μm, and 1–100 nm was analysed in order to describe the particles’ chemical composition at the different stages. The worst working conditions (the smallest particles, 12 nm), the highest total dust concentrations, and the lowest difference between total inhalable particle and nanoparticle concentrations were detected among woodworkers. These findings provide a basis on how to evaluate nanoparticle exposure and its impact on workers’ health because the highest immune cell counts and relatively high IL-6 expression were observed among woodworkers compared with the other groups. The data show a negative tendency of nanoparticle exposure concentrations on workers’ health based on the increase of inflammatory processes and damage to airway epithelial cell functionality.
Curcumin effect on copper transport in HepG2 cells
(2018-05) Berzina, Anita; Martinsone, Inese; Svirskis, Simons; Murovska, Modra; Kalis, Martins; Institute of Occupational Safety and Environmental Health; Institute of Microbiology and Virology
Background and Objective: In Wilson’s disease, copper metabolism is impaired due to defective copper transporting protein ATP7B, resulting in copper accumulation in liver and brain and causing damage to liver and brain tissues. Published data suggest that one of the possible treatments for Wilson’s disease is curcumin—a compound found in the root of Curcuma longa. In this study, we tested whether curcumin affects copper transport and excretion in HepG2 hepatocytes carrying wildtype ATP7B. Materials and Methods: We examined the impact of 5 µM and 25 µM curcumin on the transport of copper in HepG2 cells incubated with 20 µM and 100 µM CuCl2, as well as copper excretion from cells. First, immunofluorescent staining and co-localization analysis were carried out in HepG2 cells using confocal laser scanning microscope and Nikon NIS Elements software. Second, a concentration of copper extracted into cell culture medium was determined using atomic absorption spectrometry. Results: The analysis of the co-localization between Golgi complex and ATP7B revealed that both 5 µM and 25 µM doses of curcumin improve the ability of liver cells to transport copper to plasma membrane at 20 µM CuCl2, but not at 100 µM CuCl2 concentration. However, atomic absorption spectrometry showed that curcumin rather promotes copper absorption into liver cell line HepG2 than excretion of it. Conclusions: Curcumin accelerates the transport of copper within liver cells, but does not promote copper excretion from HepG2 cells.
Data for characterisation of nanoformulations formed by cationic 1,4-dihydopyridine and calix[4]arene compositions
(2022-04) Rucins, Martins; Rodik, Roman; Plotniece, Aiva; Pikun, Nadiia; Plotniece, Mara; Sobolev, Arkadij; Kalchenko, Vitaly; Pajuste, Karlis; Department of Pharmaceutical Chemistry
In this data file the characterisation of nanoformulations obtained from calix[4]arene/1,4-dihydropyridine (1,4-DHP) compositions in the various component ratio in an aqueous medium was performed by dynamic light scattering (DLS) technique. The hydrodynamic diameters of nanoparticle main population, polydispersity index and stability of nanoformulation were determined. In this article provided data are directly related to the previously published research articles – “Gene delivery agents possessing antiradical activity: Self-assembling cationic amphiphilic 1,4-dihydropyridine derivatives” [1], and “Studies of the physicochemical and structural properties of self-assembling cationic pyridine derivatives as gene delivery agents” [2] where was described synthesis, transfection activity of 1,1′-((3,5-bis((dodecyloxy)carbonyl)-4-phenyl-1,4-dihydropyridine-2,6-diyl)bis(methylene))bis(pyridin-1-ium) dibromide presented in this data file; and with articles “Cationic amphiphilic calixarenes to compact DNA into small nanoparticles for gene delivery” [3] and “Self-aggregation in aqueous solution of amphiphilic cationic calix[4]arenes. Potential use as vectors and nanocarriers” [4] where was described synthesis and ability to condense DNA for also mentioned calix[4]arenes – 5,11,17,23-tetra-(3-methylimidazolium)-methylene-25,26,27,28-etradodecyloxycalix[4]arene tetrachloride, 5,11,17,23-tetra(N,N-dimethyl-N-hydroxyethylammonium)-methylene-25,26,27,28-tetradodecyloxycalix[4]arene tetrachloride and 5,11,17,23-tetra(N,N-dimethyl-N-hydroxyethylammonium)-methylene-25,26,27,28-tetrahexadecyloxycalix[4]arene tetrachloride. Information provided in this data file can be used in medicinal chemistry for development of novel synthetic lipid nanoformulations.
Design, Fabrication, and Application of Mini-Scaffolds for Cell Components in Tissue Engineering
(2022-12) Mironov, Vladimir A.; Senatov, Fedor S.; Koudan, Elizaveta V.; Pereira, Frederico D.A.S.; Kasyanov, Vladimir A.; Granjeiro, Jose Mauro; Baptista, Leandra Santos; Joint Laboratory of Traumatology and Orthopaedics
The concept of “lockyballs” or interlockable mini-scaffolds fabricated by two-photon polymerization from biodegradable polymers for the encagement of tissue spheroids and their delivery into the desired location in the human body has been recently introduced. In order to improve control of delivery, positioning, and assembly of mini-scaffolds with tissue spheroids inside, they must be functionalized. This review describes the design, fabrication, and functionalization of mini-scaffolds as well as perspectives on their application in tissue engineering for precisely controlled cell and mini-tissue delivery and patterning. The development of functionalized mini-scaffolds advances the original concept of “lockyballs” and opens exciting new prospectives for mini-scaffolds’ applications in tissue engineering and regenerative medicine and their eventual clinical translation.
Development of Self-Assembling bis-1,4-Dihydropyridines : Detailed Studies of Bromination of Four Methyl Groups and Bromine Nucleophilic Substitution
(2024-01) Kaukulis, Martins; Rucins, Martins; Lacis, Davis; Plotniece, Aiva; Sobolev, Arkadij; Department of Pharmaceutical Chemistry
One of the most important steps in the synthesis of 1,4-dihydropyridine (1,4-DHP) amphiphiles is the bromination of methyl groups in positions 2 and 6 of the entire ring. However, up to now, only N-bromosuccinimide was mainly used for bromination 1,4-DHPs. In this work, the synthesis of bis-1,4-DHP derivatives with ethyl and dodecyl ester groups attached to 1,4-DHP ring at positions 3 and 5 was performed by Hantzsch synthesis. The experimental studies were carried out to find out the best conditions and the agent for the tetra bromination of bis-1,4-DHP methyl groups at positions 2 and 6. Four different brominating agents were screened. The use of pyridinium bromide–perbromide in ethyl acetate was found to be optimal for the bromination of methyl groups. The bromination reaction was followed by the synthesis of cationic pyridine moiety containing amphiphilic bis-1,4-DHP derivatives. By nucleophilic substitution of bromine with various substituted pyridines, 12 new amphiphilic bis-1,4-DHP derivatives were obtained. Evaluation of self-assembling properties of tetracationic bis-1,4-dihydropyridine derivatives by dynamic light scattering (DLS) measurements was also performed.
Distribution of Iron Nanoparticles in Arrays of Vertically Aligned Carbon Nanotubes Grown by Chemical Vapor Deposition
(2022-10) Okotrub, Alexander V.; Gorodetskiy, Dmitriy V.; Guselnikov, Artem V.; Kondranova, Anastasiya M.; Bulusheva, Lyubov G.; Korabovska, Mariya; Meija, Raimonds; Erts, Donats
Arrays of aligned carbon nanotubes (CNTs) are anisotropic nanomaterials possessing a high length-to-diameter aspect ratio, channels passing through the array, and mechanical strength along with flexibility. The arrays are produced in one step using aerosol-assisted catalytic chemical vapor deposition (CCVD), where a mixture of carbon and metal sources is fed into the hot zone of the reactor. Metal nanoparticles catalyze the growth of CNTs and, during synthesis, are partially captured into the internal cavity of CNTs. In this work, we considered various stages of multi-walled CNT (MWCNT) growth on silicon substrates from a ferrocene–toluene mixture and estimated the amount of iron in the array. The study showed that although the mixture of precursors supplies evenly to the reactor, the iron content in the upper part of the array is lower and increases toward the substrate. The size of carbon-encapsulated iron-based nanoparticles is 20–30 nm, and, according to X-ray diffraction data, most of them are iron carbide Fe3C. The reasons for the gradient distribution of iron nanoparticles in MWCNT arrays were considered, and the possibilities of controlling their distribution were evaluated.
An easy route to aziridine ketones and carbinols
(2021-12-05) Strumfs, Boriss; Hermane, Jekaterina; Belyakov, Sergey; Sobolevs, Artjoms; Velikijs, Kirils; Uljanovs, Romans; Trapencieris, Peteris; Strumfa, Ilze; Department of Pathology; Faculty of Medicine
N,N-Dimethylaziridine-2-carboxamides react with organolithium reagents yielding 2-aziridinylketones. The reaction with one equivalent of organolithium compound is selective to amide carbonyl at a low (−78◦C) temperature. These ketones, in reaction with organolithium reagents, give symmetrical and unsymmetrical aziridinyl carbinols. The usage of excess phenyllithium may serve as a special N-Boc-protecting group cleavage method for acid-sensitive substrates.

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Browsing Research outputs from Pure / Zinātniskās darbības rezultāti no ZDIS Pure by Subject "1.4 Chemical sciences"

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