Ryszard Krzyminiewski

Synthesis and in vitro and in vivo evaluations of poly(ethylene glycol)-block-poly(4-vinylbenzylphosphonate) magnetic nanoparticles containing doxorubicin as a potential targeted drug delivery system

The main challenge in antitumor chemotherapy is to enhance the curative effect and minimize the adverse effects of an anticancer drug. Administration of functionalized magnetic iron oxide nanoparticles is one of the strategies to improve sensitivity to cancer chemotherapy, and these nanoparticles are attractive materials that have been widely used in medicine for various applications, including diagnostic imaging and therapeutic applications. In this study, we describe the synthesis and characterization of drug-loaded iron oxide nanoparticles. Our aim was to obtain a biocompatible and injectable nanocarrier with anticancer activity. Iron oxide nanoparticles (IONs) were synthesized by alkali co-precipitation of iron salts followed by coating with our original surface modification agent, poly(ethylene glycol)-block-poly(4-vinylbenzylphosphonate) copolymer (PEG-PIONs). An anticancer drug doxorubicin (DOX), which clinical use is associated with cardiotoxicity, was loaded onto PEG-PIONs (PEG-PIONs/DOX), and to the best of our knowledge, this formulation showed higher drug encapsulation efficiency (drug loading capacity of the nanocarrier was 11.7%) than other formulations previously reported. PEG-PIONs/DOX had a hydrodynamic diameter of about 35nm and were stable in biological conditions over a period more than one month and showed stable and continuous in vitro drug release and antiproliferative effects on cancer cells. Fluorescent imaging indicated internalization of the PEG-PIONs/DOX in the cytoplasm of cancer cells. Biodistribution studies showed that PEG-PIONs/DOX preferentially accumulate in the tumor region via enhanced permeability and retention effect. In addition, analysis of the serum levels of enzymes indicated that PEG-PIONs/DOX reduced the cardiotoxicity associated with free DOX. These results indicate that PEG-PIONs/DOX have the potential for targeted delivery of antitumor drugs via systemic administration.

EPR study of the stable radical in a γ-irradiated single crystal of progesterone

Abstract The molecular structure of free radicals formed in a γ-irradiated single crystal of progesterone was investigated by EPR spectroscopy. Two different types of radicals with different rates of recombination were observed. It is proposed that the stable radical is formed by the loss of a hydrogen atom in position 6 of the molecule, leaving an unpaired electron in the 2pz orbital of the carbon atoms in positions 6 and 4. The hyperfine spectrum of this radical originates from the interaction of the unpaired electron with the two equivalent a protons in positions 4 and 6 and with the two non-equivalent β protons in position 7. The hyperfine tensors of the couplings are given together with the g tensor of this radical.

An EPR study of γ-irradiated single crystals of cholesta-4, 6-diene-3-one

Abstract Cholesta-4, 6-diene-3-one single crystals irradiated with γ-rays at room temperature have been investigated by electron spin resonance. EPR spectra at room temperature exhibit a characteristics triplet which splits into two doublets. The main triplet has been interpreted as being caused by the addition of a hydrogen atom to the 7-position of the molecule, leaving an unpaired electron in the 2p2 orbital of the carbon atoms in position 6 and 4. The hyperfine spectrum is generated by interaction of the unpaired electron with two equivalent α-protons in position 4 and 6 and with tow non-equivalent β-protons in position 7. The principal values of the hydrogen hyperfine tensors are determined together with the g tensor of this radical.

Computer enhancement of CW-EPR experimental spectra resolution as a new method in investigation of molecular dynamics in pyridinium tetrafluoroborate

Abstract The present paper reports an application of the computer method for enhancing resolution of complex CW-EPR spectra. The computer resolution enhancement method (CREM) is based on the Fourier transform, convolution and deconvolution of functions and permits determination of the fundamental parameters of the spectra: the number of resonance lines, their positions, core width parameter, and relative ratios of intensities. Thanks to the use of a simulation procedure performed with the earlier determined parameters of the spectra, we were able to find the temperature changes of the widths of individual spectral lines. An example illustrating the advantages of the CREM is the possibility of investigation of molecular dynamics and phase transitions by the CREM-aided CW-EPR. Dynamics of the radical in a complex of pyridine with tetrafluoroboric acid is reflected in changes in the hyperfine structure, core width parameter and width of individual lines in the spectrum. These changes are detectable for the complex in both powdered and single-crystal form.

Radiation damage in androst-4-en-3,17-dione molecules: an ESR study of free radicals in single crystals

Abstract Electron spin resonance spectroscopy has been used to investigate γ-radiation damage of androst-4-en-3,17-dione molecules in single crystals. The spectra found are attributed to hydrogen abstraction radicals. It is possible to assign a definite structure to the specimen by analyzing the orientational variation of the spectra. The unpaired electron of the radical is delocalized in the 2 p z -orbitals of the C(6), C(4) and O(3) atoms giving rise to a hyperfine spectrum from interaction with two equivalent α-protons in positions 4 and 6 and with two non-equivalent β-protons attached to C(7). The theoretical splittings and the spin density distribution of the unpaired electron are calculated by the INDO method.

EPR study of selected gadolinium complexes : β-diketonates and polycarboxylates

Abstract The gadolinium chelates with: acetylacetone—Gd(acac)3 · 3H2O, thenoyltrifluoroacetone—Gd(TTA)3 · 2H2O, benzoylacetone—Gd(BAC)3 · 2H2O, ethylenediaminetetraacetate Gd(EDTA) and diglycolate Gd(DGA)3 have been chosen for EPR study (X band). The EPR spectra of these complexes were obtained in the form of badly separated signals and thus were difficult to interpret. In order to improve the spectra resolution a computer analysis based on Fourier transform was applied. This analysis permitted a considerable increase in resolution of the spectra and revealed the fine structure of Gd3+ ion in the condensed phase.

An ESR study of the stable radical in a γ-irradiated single crystal of 17α-dydroxy-progesterone

Abstract Electron spin resonance spectroscopy was used to investigate γ-radiation damage of 17α-hydroxy-progesterone molecules in a single crystal. Two types of radicals with different rates of recombination were observed and a definite structure was assigned to the specimen by analyzing the orientational variation of the spectra. The unpaired electron of the radical is delocalized in the 2 p z orbitals of the C(6), C(4) and C(3) atoms, giving rise to a hyperfine spectrum by interaction with two equivalent α-protons in positions 4 and 6 and with two non-equivalent β-protons attached to C(7). The hyperfine coupling tensors are reported, together with the g tensor of the radical. The presence of additional intermolecular interactions caused by hydrogen bonding between O(3) and HO(17) of two molecules does not change the type of radical (which is the same as the stable radical in a γ-irradiated single crystal of progesterone) but does increase the hyperfine coupling anisotropy.

EPR Study of Paramagnetic Centers in Human Blood

Abstract Electron paramagnetic resonance investigations of paramagnetic centers in whole human blood were carried out at 170 K using X-band EPR spectrometer. The study included a group of patients and healthy volunteers. The EPR signals from high spin Fe3+ ions in transferrin (g = 4.2) and Cu2+ ions in ceruloplasmin (g = 2.05) are characteristic of each frozen blood sample. An overview of all recorded spectra revealed in several cases additional lines derived from high spin Fe3+ ions in methemoglobin (g = 5.8 - 6), free radicals (g = 2.002 - 2.005) and various low spin ferriheme complexes (g = 2.21 - 2.91). The lines from cytochromes (g = 3.03 and 3.27) were observed only twice. The EPR measurements have not confirmed the correlation between the occurrence of a particular type of low-spin iron complex and a specific disease entity. Moreover, the presence of EPR lines from trivalent iron also did not differentiate patients from healthy volunteers.

Plant-pathogen interactions during infection process of asparagus with Fusarium spp.

BackgroundAsparagus officinalis L. is often infected by fungi from the Fusarium genus which also contaminate the plant tissues with highly toxic secondary metabolites. To elucidate the plant-pathogen interactions between asparagus and Fusarium oxysporum or F. proliferatum, a fungal mycotoxins profile was assessed together with an impact of the infection on all forms of salicylic acid content.MethodologyFungal isolates were identified by their morphological features, species-specific PCR and transcription elongation factor 1a (TEF-1a) sequencing. Mycotoxins were assessed by high-performance liquid chromatography (HPLC). The salicylic acid and its derivatives content was analyzed by the HPLC method combined with fluorometric detection. The levels of free radicals were measured by electron paramagnetic resonance (EPR).ResultsAfter infection both Fusarium pathogens formed fumonisin B1 and moniliformin. Infection altered salicylic acid biosynthesis and conjugation rates both in the roots and stems when compared with non-inoculated plants. Samples with higher free radical concentrations in stems showed higher concentrations of all forms of salicylic acid.ConclusionsWe postulate that infection by both Fusarium pathogens produces mycotoxins, which may be transported to the upper part of plant. Pathogen attack initiated a plant defense reaction involving increased salicylic acid levels and resulting in increase in free radical levels.

EPR study of free-radical structure and conformation in pyridoxine hydrochloride single crystal

Abstract Numerical analysis of experimental EPR spectra of γ-irradiated single crystals of pyridoxine hydrochloride (vitamin B 6 ) allowed determination of the structure of the radical formed. Six hyperfine couplings were distinguished. The geometrical model of the radical was found to be in good agreement with the geometry expected from the crystal structure. Semi-empirical INDO and CNDO calculations were performed.