Gordana Zunic

Involvement of the central nervous system in the general response to pulmonary blast injury.

The local, general, and cerebral responses of rabbits exposed to pulmonary blasts were examined to define the role of vagal afferentation in cardiorespiratory as well as metabolic control after a blast injury. Two series of experiments were conducted on rabbits to analyze the general, local, and cerebral responses to pulmonary injury caused by blast overpressure, and to evaluate the effects of bilateral vagotomy on the general, local, and cerebral responses to local (pulmonary) blast injury. The blast wave was generated in laboratory conditions using an air-driven shock tube that was able to cause moderate pulmonary blast injury, i.e., four pulmonary contusions characterized as confluent ecchymoses involving 30 to 60% of the lungs. One group of animals was subjected to pulmonary deafferentation, performed by bilateral transections of the vagus, glossopharyngeal, and hypoglossal nerves. Numerous hemodynamic as well as biochemical parameters were observed in systemic circulation and in lung and brain (medulla oblongata) tissues. After observation during the early posttraumatic period, rabbits were sacrificed by decapitation 30 minutes after the blast injury. On the basis of obtained results, it was concluded that vagal afferents have an important role in the modification of general and local responses to a pulmonary blast injury. Furthermore, it was suggested that functional changes in medulla oblongata may be the consequences of afferent neural impulses from the injured region (lungs) rather than consequences of ischemia, energy transfer to the brain, or both.

Association of oxidative stress and PON1 with LDL and HDL particle size in middle‐aged subjects

Background  Alterations in plasma lipoprotein subclass distributions affect atherosclerosis risk. Smaller, denser low‐density lipoprotein (LDL) particles (sdLDL) are more susceptible to oxidation. In contrast, most of the protective effects of high‐density lipoproteins (HDL) are attributable to larger particles. This study investigates the connection between LDL and HDL particle heterogeneity and oxidative stress, antioxidative defence (AOD) and paraoxonase (PON1) status in a healthy middle‐aged Serbian population.

Capillary electrophoresis method optimized with a factorial design for the determination of glutathione and amino acid status using human capillary blood

Plasma aromatic and sulfur containing amino acids are good indicators of protein anabolism/catabolism, while blood reduced and oxidized glutathione reflect oxidative status in an organism. Using a full factorial design for screening important variables (pH, concentration, temperature) we developed a capillary zone electrophoresis method permitting their measurements in the single run, without any derivatization procedures. The best separations were obtained within less than 30 min employing a 10 mmol/l phosphate buffer, pH 2.8, 18 degrees C, 15 kV voltage. Fairly good precision with a linear relationship between peak area and concentrations (r=0.995-0.999) were obtained. The method was used to analyze human capillary blood.

Early plasma amino acid pool alterations in patients with military gunshot/missile wounds.

Plasma amino acid profiles in patients during the early period (first 18 hours) following military gunshot/missile wounds were investigated. Patients (n = 29) were casualties from the war in the former Yugoslavia with injury severity scores ranging from 4 to 18. They were divided into three groups: soft tissue (muscle) damage, wounds with fractures, and vital structures injured. Controls were normal blood donors (n = 17). Free amino acids were analyzed in venous plasma. Increased concentrations of phenylalanine and glutamine associated with increased molar phenylalanine/tyrosine ratio in plasma indicated increased net protein catabolism in the peripheral tissues, regardless of the type of injured tissues. Decreased plasma arginine, ornithine and citrulline levels, accompanied with increased molar glutamine/valine ratio, suggested disturbance in urea cycle activity, although urea level was not altered. We concluded that early changes in plasma amino acid pool characteristics after wounds were of systemic origin, not related to the type of injured tissues.

Leukotrienes in the pathogenesis of pulmonary blast injury.

Our previous studies demonstrate a significant increase of sulfidopeptide leukotriene concentrations in animals exposed to a free air blast. The aim of this study was to analyze the role of leukotrienes in the local response of lung tissue as well as in the general response of organisms to blast overpressure. The study was conducted on adult rabbits exposed to moderate blast overpressure (four pulmonary contusions characterized as confluent ecchymoses involving 30 to 60% of the lungs), generated in laboratory conditions. One group of experimental animals was treated with 5-lipoxygenase (5-LO) inhibitor, diethylcarbamazine (DEC, Sigma, St. Louis, Missouri) (50 mg/kg, i.v.), immediately before blast. The early posttraumatic period was observed (30 minutes after blast). Hemodynamic parameters (mean arterial pressure, heart rate, blood gases) as well as arterial plasma levels of conjugated dienes were observed. The myeloperoxidase activity, lipid peroxidation products levels, and water contents were measured in the lung tissue of injured rabbits. We observed that 5-LO inhibition reduced edema formation, accumulation of neutrophils, and generation of lipid peroxidation products in injured lungs. In this study, we demonstrated that treatment with DEC inhibits the increased systemic generation of conjugated dienes after blast injury. Although DEC exerts local antioxidant activity with beneficial effects on lung tissue, this 5-LO inhibitor intensifies the blast overpressure caused hemodynamic insufficiency.