Snežana Uskoković-Marković

Radioprotectors – the Evergreen Topic

To protect organisms from ionizing radiation (IR), and to reduce morbidity or mortality, various agents, called radioprotectors, have been utilized. Because radiation‐induced cellular damage is attributed primarily to the harmful effects of free radicals, molecules with radical‐scavenging properties are particularly promising as radioprotectors. Early development of such agents focused on thiol synthetic compounds, known as WR protectors, but only amifostine (WR‐2721) has been used in clinical trials as an officially approved radioprotector. Besides thiol compounds, various compounds with different chemical structure were investigated, but an ideal radioprotector has not been found yet. Plants and natural products have been evaluated as promising sources of radioprotectors because of their low toxicity, although they exhibit an inferior protection level compared to synthetic thiol compounds. Active plant constituents seem to exert the radioprotection through antioxidant and free radical‐scavenging activities. Our research established that plants containing polyphenolic compounds (raspberry, blueberry, strawberry, grape, etc.) exhibit antioxidative activities and protect genetic material from IR.

Multi-analytical study of techniques and palettes of wall paintings of the monastery of Žiča, Serbia

The present multi-analytical study concentrates on establishing the painting techniques and the identity of the wall painting materials used by the artists from the 13th and 14th centuries to decorate the Žiča monastery, Serbia. For this purpose, we demonstrate that micro-Raman spectroscopy is an efficient, non-destructive method with high spatial resolution which gives molecular and crystal structural information of a wide variety of both inorganic and organic materials. It is shown that elementary composition revealed through scanning electron microscopy with energy dispersive X-ray spectroscopy and energy dispersive X-ray fluorescence spectroscopy is necessary in some cases to confirm the identity of pigments and binders identified by micro-Raman spectroscopy. It was found that a fresco technique, in combination with mainly natural earth pigments such as red ochre, yellow ochre and green earth, was used. Expensive natural pigment lapis lazuli was exclusively used for obtaining blue colour while pure vermilion was used by the artists from the first period of decorations at the beginning of the 13th century. A mixture of pigments was used for attaining different colour shades. For the gilding of saints haloes, thin golden foil was deposited over the tin sheet. In order to get a desirable optical and aesthetical impression, the metallic leaves were deposited over the yellow ochre preparatory layer. Deposits of gypsum on wall paintings as well as traces of weddellite are degradation products formed as a result of exposing wall paintings to environmental conditions.

Raman Spectroscopy as a New Biochemical Diagnostic Tool

Summary In this review, Raman spectroscopy is described as a new and potentially powerful diagnostic tool in comparison to routine biochemical tests. Advanced instrumentation and new Raman spectroscopy techniques enable rapid and simultaneous identification and/or determination of several biochemical parameters, such as glucose, acetone, creatinine, urea, lipid profile, uric acid, total protein, etc, with a very low limit of detection. Raman spectroscopy could also be applied in molecule and cell characterization, as well as diagnostics of atherosclerosis in its early stage. Raman spectroscopy is nondestructive and could be applied to all kinds of samples, which simplifies the diagnostics of numerous diseases and pathologic states. Special attention is paid to literature data illustrating the application of Raman spectroscopy for transdermal glucose monitoring and cancer diagnostics. Kratak sadržaj U ovom prikazu opisana je primena Ramanske spektrosko- pije kao nove metode velikih mogućnosti u dijagnostici, u poređenju sa rutinskim biohemijskim testovima. Metoda je razvijena i usavršena za identifikaciju i/ili određivanje velikog broja biohemijskih parametara, kao što su glukoza, aceton, kreatinin, urea, lipidni profil, mokraćna kiselina, ukupni proteini i drugi, uz veoma nizak limit detekcije. Ramanska spek- troskopija takođe se može primenjivati u molekulskoj i ćelij- skoj karakterizaciji, kao i za dijagnostiku ranog stadijuma ateroskleroze. Ramanska spektroskopija je nedestruktivna i može se primenjivati na sve vrste uzoraka, što pojednostavljuje dijagnostiku brojnih bolesti i patoloških stanja. Posebna pažnja u radu je posvećena podacima iz literature koji ilustru- ju primenu Ramanske spektroskopije u transdermalnom monitoringu glukoze i dijagnostici kancera

Profiling differences in chemical composition of brain structures using Raman spectroscopy.

Raman spectroscopy enables non-invasive investigation of chemical composition of biological tissues. Due to similar chemical composition, the analysis of Raman spectra of brain structures and assignment of their spectral features to chemical constituents presents a particular challenge. In this study we demonstrate that standard and independent component analysis of Raman spectra is capable of assessment of differences in chemical composition between functionally related gray and white matter structures. Our results show the ability of Raman spectroscopy to successfully depict variation in chemical composition between structurally similar and/or functionally connected brain structures. The observed differences were attributed to variations in content of proteins and lipids in these structures. Independent component analysis enabled separation of contributions of major constituents in spectra and revealed spectral signatures of low-concentration metabolites. This provided finding of discrepancies between structures of striatum as well as between white matter structures. Raman spectroscopy can provide information about variations in contents of major chemical constituents in brain structures, while the application of independent component analysis performed on obtained spectra can help in revealing minute differences between closely related brain structures.

An Improved HPLC Method with the Aid of a Chemometric Protocol: Simultaneous Determination of Atorvastatin and Its Metabolites in Plasma

The aim of the present study was to optimize a chromatographic method for the analysis of atorvastatin (acid and lactone forms), ortho- and para-hydroxyatorvastatin by using an experimental design approach. Optimization experiments were conducted through a process of screening and optimization. The purpose of a screening design is to identify the factors that have significant effects on the selected chromatographic responses, and for this purpose a full 23 factorial design was used. The location of the true optimum was established by applying Derringer’s desirability function, which provides simultaneously optimization of all seven responses. The ranges of the independent variables used for the optimization were content of acetonitrile in mobile phase (60–70%), temperature of column (30–40 °C) and flow rate (0.8–1.2 mL min−1). The influences of these independent variables were evaluated for the output responses: retention time of first peak (p-hydroxyatorvastatin) and of last peak (atorvastatin, lactone form), symmetries of all four peaks and relative retention time of p-hydroxyatorvastatin. The primary goal of this investigation was establishing a new simple and sensitive method that could be used in analysis of biological samples. The method was validated and successfully applied for determination of atorvastatin (acid and lactone forms) and its metabolites in plasma.

EDXRF spectrometry determination of tungsten in tobacco plants after antiviral treatment with 12-tungstophosphoric acid and its compounds

In this study, we have developed a sensitive, rapid and simple procedure for the energy dispersive X-ray fluorescence (EDXRF) spectrometry measurement of tungsten in tobacco plant parts. Only 0.1g of dried plant material is needed instead of the usual 1g. EDXRF spectrometry is used for quantitative measurement, after the foliar application of solutions of tungstophosphoric acid (WPA), its magnesium salt and compounds with glycine (Gly) and alanine (Ala), in exact quantities. After that, the leaves, trunks and summits were collected and prepared separately. Tungsten is determined directly in raw dried material, and the overlap of the tungsten peak with zincs that is present is avoided by the spectral deconvolution to obtain quantitative results. The prepared dry tablets weighed 100mg, and measurement time was 2000s. The radioisotope excitation source used was (109)Cd and tungsten was identified and quantified at the L(alpha1) and L(alpha2) lines at the energies of 8397.6eV and 8335.2eV, respectively. EDXRF spectrometry was applied in a wide range of concentrations (up to 2000mg/kg), with an estimated detection concentration limit of 15mg/kg, calculated on dried material. Quantitative analysis of different parts of the treated plant plus the washings gave 94.47% recovery of the applied tungsten in different compound forms. After the foliar application of investigated WPA compounds, there were noticed both vertical and horizontal distributions of tungsten through out the tobacco plants, according to the EDXRF spectrometry results. This conclusion is also in agreement with the positive effects of WPA on Tobacco mosaic tobamovirus (TMV) infection of Nicotiana tabacum (Solanaceae).

Intermolecular and low-frequency intramolecular Raman scattering study of racemic ibuprofen.

We report the low-temperature Raman scattering study of racemic ibuprofen. Detailed analysis of the racemic ibuprofen crystal symmetry, related to the vibrational properties of the system, has been presented. The first principle calculations of a single ibuprofen molecule dynamical properties are compered with experimental data. Nineteen, out of 26 modes expected for the spectral region below 200cm(-1), have been observed.