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Karlis Pajuste  - - - 
Top co-authors See all
Krisjanis Smits

72 shared publications

Institute of Solid State Physics, University of Latvia, Kengaraga str. 8, Riga LV-1063, Latvia

Gunars Duburs

52 shared publications

Latvian Institute of Organic Synthesis, Aizkraukles str. 21, Riga, LV-1006, Latvia

Aiva Plotniece

31 shared publications

Latvian Institute of Organic Synthesis, Aizkraukles Str. 21, Riga LV-1006, Latvia

Brigita Vīgante

19 shared publications

Latvian Institute of Organic Synthesis, Aizkraukles iela 21, LV-1006 Riga, Latvia;(B.V.);(M.R.);(A.S.);(M.P.);(K.P.)

Egils Bisenieks

15 shared publications

Latvian Institute of Organic Synthesis, Aizkraukles str. 21, Riga, LV-1006, Latvia

Publication Record
Distribution of Articles published per year 
(2009 - 2019)
Total number of journals
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Publications See all
Article 0 Reads 0 Citations Contribution of Molecular Structure to Self-Assembling and Biological Properties of Bifunctional Lipid-Like 4-(N-Alkylpy... Martins Rucins, Pavels Dimitrijevs, Klavs Pajuste, Oksana Pe... Published: 12 March 2019
Pharmaceutics, doi: 10.3390/pharmaceutics11030115
DOI See at publisher website ABS Show/hide abstract
The design of nanoparticle delivery materials possessing biological activities is an attractive strategy for the development of various therapies. In this study, 11 cationic amphiphilic 4-(N-alkylpyridinium)-1,4-dihydropyridine (1,4-DHP) derivatives differing in alkyl chain length and propargyl moiety/ties number and position were selected for the study of their self-assembling properties, evaluation of their cytotoxicity in vitro and toxicity on microorganisms, and the characterisation of their interaction with phospholipids. These lipid-like 1,4-DHPs have been earlier proposed as promising nanocarriers for DNA delivery. We have revealed that the mean diameter of freshly prepared nanoparticles varied from 58 to 513 nm, depending upon the 4-(N-alkylpyridinium)-1,4-DHP structure. Additionally, we have confirmed that only nanoparticles formed by 4-(N-dodecylpyridinium)-1,4-DHP derivatives 3 and 6, and by 4-(N-hexadecylpyridinium)-1,4-DHP derivatives 10 and 11 were stable after two weeks of storage. The nanoparticles of these compounds were found to be homogenous in size distribution, ranging from 124 to 221 nm. The polydispersity index (PDI) values of 1,4-DHPs samples 3, 6, 10, and 11 were in the range of 0.10 to 0.37. We also demonstrated that the nanoparticles formed by 4-(N-dodecylpyridinium)-1,4-DHP derivatives 3, 6, and 9, and 4-(N-hexadecylpyridinium)-1,4-DHP derivatives 10 and 11 had zeta-potentials from +26.07 mV (compound 6) to +62.80 mV (compound 11), indicating a strongly positive surface charge and confirming the relative electrostatic stability of these nanoparticle solutions. Transmission electron microscopy (TEM) images of nanoaggregates formed by 1,4-DHPs 3 and 11 confirmed liposome-like structures with diameters around 70 to 170 nm. The critical aggregation concentration (CAC) value interval for 4-(N-alkylpyridinium)-1,4-DHP was from 7.6 µM (compound 11) to 43.3 µM (compound 6). The tested 4-(N-alkylpyridinium)-1,4-DHP derivatives were able to quench the fluorescence of the binary 1,6-diphenyl-1,3,5-hexatriene (DPH)—1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) system, demonstrating hydrophobic interactions of 1,4-DHPs with phospholipids. Thus, 4-(N-dodecylpyridinium)-1,4-DHP derivative 3 quenched the fluorescence of the DPH–DPPC system more efficiently than the other 4-(N-alkylpyridinium)-1,4-DHP derivatives. Likewise the compound 3, also 4-(N-dodecylpyridinium)-1,4-DHP derivative 9 interacted with the phospholipids. Moreover, we have established that increasing the length of the alkyl chain at the quaternised nitrogen of the 4-(N-alkylpyridinium)-1,4-DHP molecule or the introduction of propargyl moieties in the 1,4-DHP molecule significantly influences the cytotoxicity on HT-1080 (human fibrosarcoma) and MH-22A (mouse hepatocarcinoma) cell lines, as well as the estimated basal cytotoxicity. Additionally, it was demonstrated that the toxicity of the 4-(N-alkylpyridinium)-1,4-DHP derivatives on the Gram-positive and...
Article 0 Reads 0 Citations Synthesis and Comparative Evaluation of Novel Cationic Amphiphile C12-Man-Q as an Efficient DNA Delivery Agent In Vitro Gunita Apsite, Irena Timofejeva, Aleksandra Vezane, Brigita ... Published: 26 June 2018
Molecules, doi: 10.3390/molecules23071540
DOI See at publisher website PubMed View at PubMed ABS Show/hide abstract
New amphiphilic 1,4-DHP derivative C12-Man-Q with remoted cationic moieties at positions 2 and 6 was synthesised to study DNA delivery activity. The results were compared with data obtained for cationic 1,4-DHP derivative D19, which is known to be the most efficient one among the previously tested 1,4-DHP amphiphiles. We analysed the effects of C12-Man-Q concentration, complexation media, and complex/cell contact time on the gene delivery effectiveness and cell viability. Transmission electron microscopy data confirms that lipoplexes formed by the compound C12-Man-Q were quite uniform, vesicular-like structures with sizes of about 50 nm, and lipoplexes produced by compound D19 were of irregular shapes, varied in size in the range of 25–80 nm. Additionally, confocal microscopy results revealed that both amphiphiles effectively delivered green fluorescent protein expression plasmid into BHK-21 cells and produced a fluorescent signal with satisfactory efficiency, although compound C12-Man-Q was more cytotoxic to the BHK-21 cells with an increase of concentration. It can be concluded that optimal conditions for C12-Man-Q lipoplexes delivery in BHK-21 cells were the serum free media without 0.15 M NaCl, at an N/P ratio of 0.9. Compound D19 showed higher transfection efficiency to transfect BHK-21 and Cos-7 cell lines, when transfecting active proliferating cells. Although D19 was not able to transfect all studied cell lines we propose that it could be cell type specific. The compound C12-Man-Q showed modest delivery activity in all used cell lines, and higher activity was obtained in the case of H2-35 and B16 cells. The transfection efficiency in cell lines MCF-7, HeLa, and Huh-7 appears to be comparable to the reference compound D19 and minimal in the HepG2 cell line.
Article 0 Reads 0 Citations An efficient synthesis of multisubstituted 4-nitrobuta-1,3-dien-1-amines and application in cyclisation reactions Brigita Vīgante, Aiva Plotniece, Mārtiņš Ruciņš, Marina Petr... Published: 01 May 2018
Tetrahedron, doi: 10.1016/j.tet.2018.03.075
DOI See at publisher website
Article 0 Reads 1 Citation Study of interactions of mononucleotides with 1,4-dihydropyridine vesicles using NMR and ITC techniques Ruslan Muhamadejev, Marina Petrova, Rufus Smits, Aiva Plotni... Published: 01 January 2018
New Journal of Chemistry, doi: 10.1039/c8nj00160j
DOI See at publisher website
Article 2 Reads 3 Citations Direct Aminolysis of Ethoxycarbonylmethyl 1,4-Dihydropyridine-3-carboxylates Brigita Vigante, Martins Rucins, Aiva Plotniece, Karlis Paju... Published: 12 November 2015
Molecules, doi: 10.3390/molecules201119697
DOI See at publisher website PubMed View at PubMed ABS Show/hide abstract
The ethoxycarbonylmethyl esters of 1,4-dihydropyridines were directly converted into carbamoylmethyl esters in the presence of 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD) in good to excellent yields under mild conditions. The use of TBD is crucial for the successful aminolysis of ethoxycarbonylmethyl ester of 1,4-dihydropyridines with secondary amines as without it the reaction does not proceed at all. The aminolysis reaction proceeded regioselectively, as the alkyl ester conjugated with the 1,4-dihydropyridine cycle was not involved in the reaction. Screening of other N-containing bases, such as triethylamine (TEA), pyridine, 4-(N,N-dimethylamino)pyridine (DMAP), 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU), 1,5-diazabicyclo[4.3.0]non-5-ene (DBN), imidazole, tetramethyl guanidine (TMG) and 7-methyl-1,5,7-triazabicyclo[4.4.0]dec-5-ene (MTBD) as catalysts revealed no activity in the studied reaction.
Article 0 Reads 3 Citations Studies of the physicochemical and structural properties of self-assembling cationic pyridine derivatives as gene delive... Oksana Petrichenko, Martins Rucins, Aleksandra Vezane, Irena... Published: 01 October 2015
Chemistry and Physics of Lipids, doi: 10.1016/j.chemphyslip.2015.08.005
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