The effects of acute hyperhomocysteinemia induced by DL-homocysteine or DL-homocysteine thiolactone on serum biochemical parameters, plasma antioxidant enzyme and cardiac acetylcholinesterase activities in the rat

The aim of this study was to assess the effects of DL-homocysteine (DL-Hcy) and DL-homocysteine thiolactone (DL-Hcy TLHC) on selected serum biochemical parameters, markers of oxidative stress and the activities of antioxidant enzymes (catalase (CAT), glutathione peroxidase (GPx), superoxide dismutase (SOD)) in the plasma, as well as on acetylcholinesterase (AChE) activity in the cardiac tissue homogenate in the rat. Male Wistar rats were divided into three groups as follows: control group (1 mL 0.9% NaCl, intraperitoneal (i.p.) injection), DL-Hcy group (8 mmol/kg body mass (b.m.), i.p.) or DL-Hcy TLHC group (8 mmol/kg b.m., i.p.). One hour after administration, the rats were euthanized, whole blood was collected for biochemical analysis, and the heart was excised. Following the i.p. administration of DL-Hcy and DL-Hcy TLHC, the activities of antioxidant enzymes were mostly significantly increased, while plasma malondialdehyde (MDA) was decreased. Administration of DL-Hcy and DL-Hcy TLHC significantly inhibited AChE activity in rat cardiac tissue. Our findings suggest that DL-Hcy and DL-Hcy TLHC exerted prooxidant effects; however, the decrease in MDA points to an inverse response to the increase in antioxidant enzyme activities. While both substances inhibited AChE activity in rat cardiac tissue, DL-Hcy TLHC induced stronger effects than DL-Hcy

Preparative separation of enantiomers of inhalation anaesthetic gases by using Pressure Swing Adsorption

About one third of all synthetic drugs are produced in the form of racemates, containing two enantiomers of the same substance, although only one of them is effective. Studies on racemic anaesthetic gases indicate that pure enantiomers may have better pharmacological properties in comparison to the racemate. In order to design improved anaesthetics, it is important to further investigate the mechanism of the action of pure enantiomers and to develop efficient methods of their separation. In this work fluorinated volatile anaesthetics like isoflurane, enflurane and desflurane are investigated. There are different processes for separation of these gases, like capillary chromatography, as well as more advanced multi-column options like Simulated Moving Beds (SMB) and Pressure Swing Adsorption (PSA). This work considers the separation of enantiomers of anaesthetic gases by dynamic simulation of a PSA process. The basic case of a single column with four steps was studied and modelled as a system of differential algebraic equation, which were solved using gPROMS software. Information about the system and adsorption isotherms were taken from the literature as well as obtained experimentally using columns packed with modified cyclodextrin supported on porous glass beads. Illustration of a simple PSA process for separation of the aforementioned anaesthetic gases will be shown, as well as simulation results that involve parametric studies of the process performance, measured in terms of purity, recovery and productivity of the target enantiomer