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This review focuses on analytical methods for the determination of reactive oxygen species (ROS): a superoxide/ hydroperoxyl radical, hydrogen peroxide, singlet oxygen and a hydroxyl radical. The methods which are described in this paper are based on: electron paramagnetic resonance spectroscopy (EPR), nuclear magnetic resonance (NMR), mass spectroscopy (MS), spectroscopy UV-Vis, gas chromatography (GC), chemiluminescence (CL), fluorescence (FL), HPLC –UV, iodide titration, and 14C-formate oxidation. In this review, the most common analytical methods for the detection of ROS generated by chemical methods are presented. The methods are based on the direct as well as indirect detection of ROS.

The studies of new anti-cancer drugs are constantly in the centre of scientific interest. This paper provides an overview of the complex compounds of platinum(II) and palladium(II) as anti-cancer drugs. These drugs have been described in dependence on the type of cells which are under the influence of the cytotoxic drug and side effects arising from the use of the drug. In the case of some drugs such as cisplatin or trans-[PtCl2(tz)2] the mechanisms of action in the body are described. Furthermore, in the paper the methods used for cytotoxicity determination of chemical compounds considered to be used as anticancer drugs are described. The MTT, MTS, LDH, BrdU, Alamar Blue and Neutral Red test are examples of such methods.

Although there are many different methods for measuring the carbon monoxide and carbon dioxide content under biological conditions, not all of them are appropriate for detecting the very low concentrations. This review discusses the principles of the most commonly used methods for the detection and quantitative determination of these species, as well as the advantages and limitations of the methods described. The considered analytical methods are discussed in relation to their accuracy, precision and sensitivity together with the extent to which any interference can occur. The described methods for measuring carbon monoxide content under biological conditions fall into six main groups, while in the case of the quantitative determination of carbon dioxide the use of ten techniques is discussed.

The biological and toxicological effects caused by nitric oxide and nitrogen dioxide, more commonly known as reactive nitrogen species (RNS), have increasingly stirred scientific curiosity about the molecular mechanisms of RNS activity in human body. These radicals possess certain characteristics that complicate their detection, namely their short lifetime and lack of specificity as they react with a variety of endogenous compounds present in biological samples. The development of reliable detection and quantification methods that are sensitive and specific is thus important. Today, nitric oxide can be detected and determined quantitatively by various analytical methods, such as colorimetry, spectrophotometry, electrochemistry, fluorescence, chemiluminescence, electron paramagnetic resonance, gas and liquid chromatography, electrophoresis and mass spectrometry. On the other hand, there are only a few methods capable of measuring nitrogen dioxide. The aim of the present article is to give an overview of the commonly used analytical methods for measuring ·NO and ·NO2 in biological systems. The underlying mechanisms and principles of these methods are discussed.

This review addresses a few vital issues pertaining to the chemical aspect of inflammatory stress mediated by •NO2. Consequently, in this paper we have presented a short description of different instrumental methods for the detection of nitrogen dioxide (•NO2) in biological material and have demonstrated new instrumental method focusing on the reaction between an •NO2 and the two novel coordination ions of cis-[Cr(C2O4)(L-L)(OH2)2] [with L-L denoting either methyl 3-amino-2,3-dideoxy--D-arabino-hexopyranoside (AaraNH2) or methyl 3-amino-2,3-dideoxy--D-arabinohexopyranoside (BaraNH2)] studied by the stopped-flow technique. In order to investigate the biochemistry of •NO2 mediated inflammatory stress, we developed our method for specific detection of this radical in biological samples from pancreatic extracts and managed to identify •NO2 as an agent nitrating membrane localized proteins, as well as a selective oxidant of critical SH groups within membrane buried proteins. We have proved that the method is applicable to •NO2 assessment in tissue samples from rats with acute pancreatitis induced by L-arginine, where oxidative and nitrosative stress are supposed to play a key role in the pathomechanism of the disease.

It has been suggested that the alanine-based peptide with sequence Ac-XX-[A]7-OO-NH2, termed XAO where X denotes diaminobutyric acid and O denotes ornithine, exists in a predominantly polyproline-helix (PII) conformation in aqueous solution. In our recent work, we demonstrated that this “polyproline conformation” should be regarded as a set of local conformational states rather than as the overall conformation of the molecule. In this work, we present further evidence to support this statement. Differential scanning calorimetry measurements showed only a very small peak in the heat capacity of an aqueous solution of XAO at 57°C, whereas the suggested transition to the PII structure should occur at ∼30°C. We also demonstrate that the temperature dependence of the 3JHNHα coupling constants of the alanine residues can be explained qualitatively in terms of Boltzmann averaging over all local conformational states; therefore, this temperature dependence proves that a conformational transition does not occur. Canonical MD simulations with the solvent represented by the generalized Born model, and with time-averaged NMR-derived restraints, demonstrate the presence of an ensemble of structures with a substantial amount of local PII conformational states but not with an overall PII conformation.

Cationic standard homoconjugation constants were determined in systems containing heterocyclic and aliphatic amine N-oxides, and pyridine, in two polar aprotic solvents: weakly basic protophobic nitromethane (NM); and strongly basic protophilic N, N- dimethylformamide (DMF). The constant values were compared with those previously determined in other polar non-aqueous solvents. In the case of the N-oxides with hydrogen-bonded bridges of the OHO+type, heteroconjugation equilibria were present in the majority of the systems in nitromethane and in a small number of systems in N, N- dimethylformamide. This helped to place the solvents in the series of non-aqueous media ranked according to declining tendency of the N-oxides towards cationic heteroconjugation. The rank order was consistent with increasing basicity of the polar aprotic solvents. In addition, the cationic standard heteroconjugation constants in these media were found to increase with increasing basicity of the proton acceptor and decreasing basicity of N-oxide conjugated with the proton acceptor. In the case of mixed hydrogen-bonded bridges (OHN+, NHO+type), there were no simple relationships between the tendency towards cationic heteroconjugation and basicities of the proton donor and proton acceptor, as well as the basicity of the solvent.

Proton transfer in (NHN)⁺ bridges has been demonstrated by e.m.f. measurements in cyclohexanone, propanone, and butan-2-one. The standard formation constants K^o_f of the complexes formed between pyridinium ion and 19 N-bases B (PyH⁺ + B) have been determined. Also, the reverse reactions of 19 ammonium perchlorates with free pyridine (BH⁺+ Py) have been studied, The formation constants of the complexes (PyHB⁺) range from lg K^o_f ≈ 1.5 to lg K^o_f ≈ 2.5 (standard deviations, ± 0.15). The proton transfer between Py and B in ketonic solvents requires ΔρK^o_a > 4. Copyright 1994, 1999 Academic Press

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