Radojka Pantović

Determination of standard zinc values in the intact tissues of mice by ICP spectrometry.

The most commonly encountered difficulties for the quantitative measurement of zinc in biological samples are the limited sample amount, total and effective digestion of connective and fatty residues, and low zinc concentrations. These problems often lead to the determination of lower zinc values than actually present, so that the sample preparation, digestion, and analytical procedure deserve careful attention.In this short communication, a new method for microwave tissue disintegration is described. The authors have obtained consistent and reproducible results with tissue samples of 0.5 g or less.

Effect of indomethacin on motor activity and spinal cord free fatty acid content after experimental spinal cord injury in rabbits.

Study design:Determination of functional and biochemical parameters as well as the effect of specific therapies on these parameters, in the experimental model of neurotrauma in rabbits.Objective:To assess the effect of indomethacin (0.1–3.0 mg/kg for 9 days), a potent inhibitor of endogenous prostaglandin synthesis, on the motor activity and on the spinal cord tissue concentration of free palmitic, stearic, oleic, arachidonic and docosahexaenoic acids in an experimental model of a spinal cord injury in rabbits.Setting:Faculty of Medicine, University of Rijeka, Croatia.Methods:The animals were randomly divided into nine experimental groups, four sham and/or vehicle-treated and five indomethacin-treated (including one sham-operated and four injured groups). Laminectomy was followed by contusion of the spinal cord, using a modification of the technique of Albin. Motor activity was controlled daily during the course of the next nine postoperation days and scored using Tarlovs system. Spinal cord samples from the impact injury site were taken and frozen in liquid nitrogen. Total lipids were isolated and purified by a modification of the method of Folch. Free fatty acids (FFAs) were separated from the total lipid extract by preparative thin-layer chromatography, converted to the corresponding methyl esters and identified using gas chromatography, using nonadecanoic acid as the internal standard.Results:The concentrations of all analysed free fatty acids were increased in the spinal cord after neurotrauma, in comparison to control tissues. Treatment of injured rabbits with indomethacin resulted in a significant decrease in spinal cord FFAs and exerted a positive effect on neurotrauma-induced motor impairment.Conclusion:These results indicate a mechanism whereby indomethacin protects rabbits from the sequellae of neuronal damage caused by trauma, and suggests that it may be beneficial in the therapy of neurotrauma.Sponsorship:This work was supported by the Croatian Ministry of Science and Technology (project 062019).

Metal tissue kinetics in regenerating liver, thymus, spleen and submandibular gland after partial hepatectomy in mice

Liver regeneration after partial hepatectomy (pHx) is a well-defined process, which involves the concerted action of extra- and intracellular factors resulting in induction of cell replication and its inhibition at the time when the entire liver mass is restored. Concomitantly, the breakdown of previously maintained tolerance and the exposure of self-antigens lead to the activation of preimmune and immune repertoires, which participate in surveillance against aberrant cells and the re-establishment of previous morphostasis. Because, in these events, important biological function might have tissue minerals that are affecting the structural integrity and enzyme activities, transduction signals, transcription and replication factors during cell proliferation and apoptosis, as well as the development and maintenance of immune functions and cytokine production, in this study we analyzed tissue dynamics of zinc, ioron magnesium, and calcium in the liver, thymus, spleen, and submandibular gland in intact and pHx mice on the 1st, 2nd, 7th, and 15th d after one-third pHx, using microwave digestion and inductivity coupled plasma spectrometry. The data showed that pHx induces significant and interconnected changes in all of the estimated metals not only in the regenerating liver but also in the lymphatic tissues and submandibular gland, indicating their importance for the control of growth processes.