Publications by authors named "Pisarcik M"

We describe the case of a 27-year-old male, previously healthy though with a social history notable for recreational cocaine use, who developed bone marrow failure due to aplastic anemia (AA) with associated serous fat atrophy (SFA). After the SFA was corrected with nutritional supplementation, the patient underwent successful allogeneic, haploidentical stem cell transplantation with a regimen designed to treat AA. To our knowledge, this is the first case of hematopoietic stem cell transplantation (HSCT) performed following correction of SFA.

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Caffeic acid (CA) is one of the most abundant natural compounds present in plants and has a broad spectrum of beneficial pharmacological activities. However, in some cases, synthetic derivation of original molecules can expand their scope. This study focuses on the synthesis of caffeic acid phosphanium derivatives with the ambition of increasing their biological activities.

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Introduction: Biological control of root diseases of lucerne (Medicago sativa L.) has potential benefits for stand performance but this remains unsupported by evidence from practical field studies.

Methods: In field experiments at three sites our objectives were to determine the effect of Pythium oligandrum, as spring, autumn and intensive regime treatments on (i) lucerne plant density and root traits development, and (ii) forage yield and forage traits.

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Phosphorus-containing heterocyclic cationic surfactants alkyldimethylphenylphospholium bromides with the alkyl chain length 14 to 18 carbon atoms were used for the stabilization of silver nanodispersions. Zeta potential of silver nanodispersions ranges from +35 to +70 mV, which indicates the formation of stable silver nanoparticles (AgNPs). Long-chain heptadecyl and octadecyl homologs of the surfactants series provided the most intensive stabilizing effect to AgNPs, resulting in high positive zeta potential values and smaller diameter of AgNPs in the range 50-60 nm.

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A series of alkylphosphocholines with foscarnet moiety was synthesized. The structure of these zwitterionic amphiphiles was modified in both polar and non-polar parts of surfactant molecule. Investigations of physicochemical properties are represented by the determination of critical micelle concentration, the surface tension value at the cmc and the surface area per surfactant head group utilising surface tension measurements.

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Cationic gemini surfactants with polymethylene spacer and linear alkyl chains containing an even number of carbon atoms have been extensively studied in the recent past, with the emphasis put on the determination of their aggregation behaviour in aqueous solution and their biological properties. However, the information on the aggregation of branched gemini surfactants with an odd number of carbon atoms in their alkyl chains is only sparsely reported in the literature. To help cover this gap in the research of cationic gemini surfactants, a series of branched bisammonium cationic gemini surfactants with an odd number of carbon atoms in alkyl chains (tridecane-2-yl chains) and a polymethylene spacer with a variable length ranging from 3 to 12 carbon atoms have been synthesized and investigated.

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Article Synopsis
  • Researchers created pH-sensitive liposomes using a combination of ,-dimethylalkane-1-amine-oxides and a neutral phospholipid (DOPE) to improve transfection efficiency for plasmid DNA.
  • The study found that transfection efficiency correlated with the length of the alkyl substituent, peaking at a specific length (CNO = 16), and outperforming the popular commercial reagent Lipofectamine 2000.
  • Structural analysis revealed that changes in pH triggered a phase transition that enhanced DNA release and internalization in cells, particularly at optimal compositions of CNO/DOPE.
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Self-assembly properties of cationic gemini surfactants with biodegradable amide or ester groups in the spacer were investigated utilising time-resolved fluorescence quenching, dynamic light scattering and zeta potential measurements. A correlation between aggregation parameters such as micelle aggregation number, micelle size and zeta potential with the structure of gemini molecules was made. For gemini molecules with medium spacer lengths, micelle aggregation number does not change much with the surfactant concentration.

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Glibenclamide, a drug used for the treatment of type 2 diabetes, belongs to Class II of Biopharmaceutical Classification System. It is a highly permeable, but poorly water-soluble drug. Nanoparticles of glibenclamide were prepared by an emulsion solvent evaporation method using dichloromethane as a solvent of glibenclamide and 3% (w/w) aqueous solution of carboxymethyl dextran sodium salt as a stabilizer, which was found as optimal.

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The present study is focused on the synthesis and investigation of the physicochemical and biological properties of silver nanoparticles stabilized with a series of cationic gemini surfactants having a polymethylene spacer of variable length. UV-VIS spectroscopy, dynamic light scattering, scanning electron microscopy and zeta potential measurements were applied to provide physicochemical characterization of the silver nanoparticles. The mean size values of the nanoparticles were found to be in the 50 to 115 nm range.

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Nanoparticles can be considered as a useful tool for improving properties of poorly soluble active ingredients. Hydrochlorothiazide (Class IV of the Biopharmaceutical Classification System) was chosen as a model compound. Antisolvent precipitation-solvent evaporation and emulsion solvent evaporation methods were used for preparation of 18 samples containing hydrochlorothiazide nanoparticles.

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One approach for the enhancement of oral drug bioavailability is the technique of nanoparticle preparation. Risedronate sodium (Biopharmaceutical Classification System Class III) was chosen as a model compound with high water solubility and low intestinal permeability. Eighteen samples of risedronate sodium were prepared by the solvent evaporation technique with sodium dodecyl sulfate, polysorbate, macrogol, sodium carboxymethyl cellulose and sodium carboxymethyl dextran as nanoparticle stabilizers applied in three concentrations.

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The physico-chemical properties of dialkylamino and nitrogen heterocyclic analogues of hexadecylphosphocholine (HPC) and cetyltrimethylammonium bromide (CTAB) were investigated. The surface properties, such as the critical micelle concentration (cmc), the surface tension value at the cmc (gamma(cmc)), and the surface area at the surface saturation per head group (A(cmc)) were determined by means of surface tension measurements. Micelle size was determined using the dynamic light scattering method.

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The present study deals with the determination of hydrodynamic size of DNA/cationic gemini surfactant complex in sodium bromide solution using the dynamic light scattering method. Cationic gemini surfactants with polymethylene spacer of variable length were used for the interaction with DNA. The scattering experiments were performed at constant DNA and sodium bromide concentrations and variable surfactant concentration in the premicellar and micellar regions as a function of surfactant spacer length.

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Values of the area per surfactant molecule of various single chain and gemini quaternary ammonium surfactants containing biodegradable amide and ester groups are obtained from the surface tension measurements and they are mutually compared. It was found that surfactant molecules with the ester group in their structure occupy smaller area at the air/water interface than the corresponding molecules with the amide group, mainly due to the higher conformational flexibility of ester groups. In decreasing the area per surfactant molecule value, hydrogen bonding (both inter- and intramolecular) plays a significant role when amide groups are present in the spacer of a gemini molecule.

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Aggregation properties of biodegradable ammonium surfactants containing amide and ester groups in the bulk and at the air-water interface were investigated as a function of surfactant tail length m using dynamic light scattering and surface tension experimental methods. The results indicate that surfactants containing an ester group in the structure display higher aggregation ability in the volume and form more densely packed layer of molecules at the air-water interface than those with an amide group. The results of physical measurements were correlated with 3D models of respective surfactant molecules.

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Areas per surfactant molecule at the liquid/hydrophobic solid (A(LS)) and the liquid/air (A(LA)) interface as a function of the spacer length are reported for cationic gemini surfactants having (CH2)n spacer s. A(LA) increases with increasing spacer length up to 6-8 CH2 groups in the spacer and then levels off. A(LS) values indicate a more closely packed arrangement of the surfactant molecules than that at the liquid/air interface.

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The size and structure of aggregates formed by interaction of DNA with homologous series of cationic gemini surfactants butane-1,4-diyl-bis(alkyldimethylammonium bromide) (CnGS, n=10-16 is the number of alkyl carbons) were investigated using UV-vis turbidity, dynamic light scattering and small-angle synchrotron X-ray (SAX) diffraction. The detailed analysis of turbidity in the range of lambda=450-600 nm indicates an anomaly in the growth of CnGS+DNA aggregates with increasing concentration of CnGS, possibly involving changes of structure and size of aggregates. Using dynamic light scattering, changes of the effective diameter of CnGS+DNA (n=12 and 16) aggregates formed in the CnGS concentration range 0.

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Aggregation properties of sodium hyaluronate (NaHA) with alkanediyl-alpha,omega-bis(dimethylalkylammonium bromide) surfactants (referred to as dimeric surfactants) in aqueous sodium chloride solutions have been studied as a function of surfactant chemical structure. Surface tension measurements indicate the unusual parabolic dependence of surface tension vs log surfactant concentration with a surface tension minimum at concentration c(min). The increase of surface tension above c(min) may be related to the formation of clusters consisting of NaHA chain and dimeric surfactants at the air-water interface and in the bulk.

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