Biomedical subjects

H Fiçicilar

Publications and source records attributed to H Fiçicilar.

3 recordsLinked to original sources

PubMed2000

Does the platelet-activating factor affect the antioxidant defense system? The possible role of hyperbaric oxygenation.

The platelet-activating factor (PAF) is an inflammatory mediator and it may exert some of its effects by reactive oxygen species (ROS). We investigated the effects of PAF and hyperbaric oxygenation (HBO) on copper (Cu) and zinc (Zn) levels in plasma and the intracellular antioxidant enzyme activities of rats. PAF administration caused a decrease in erythrocyte catalase (CAT) and glutathione peroxidase (GPx) activities and in the plasma zinc level. Following PAF administration, exposure to HBO also caused a decrease in erythrocyte GPx activity. These results support the hypothesis that PAF may produce free oxygen radicals and HBO enhances this effect. The enzyme activities of the antioxidant defense system were found to be affected by these oxidative processes. This is likely to be the result of excessive production of ROS or overutilization and/or inhibition of the antioxidant enzymes.

Animals↗

PubMed2000

Effects of platelet-activating factor and hyperbaric oxygenation on antioxidant defense and duodenal contractility.

Platelet-activating factor (PAF) is a phospholipid mediator with potent biological effects on organisms. Some investigators have previously postulated that PAF exerts its effects by producing oxygen free radicals. The aim of this study was to investigate the effects of PAF on intracellular antioxidant enzyme activities and on duodenal muscle contractility. The effects of hyperbaric oxygenation (HBO2) on the response to PAF were also investigated. Two experimental sets were designed. Each experimental set comprised two groups and each group consisted of six animals. The first group of the first experimental set to which only isotonic NaCl solution (serum physiologic, SP) was injected was named the control group. The second group of the first experimental set to which only PAF was administrated was named the PAF group. Blood samples and duodenum segments of both groups were obtained 2 h after the administration of PAF or SP. We observed that acetylcholine (ACh)-induced duodenal muscle contractions were more effective in the PAF group than those in the control group. Erythrocyte catalase and glutathione peroxidase (GPx) activities were found to be lower. In the second experimental set, rats administered PAF, and rats administered SP were exposed to HBO2. In both groups of this set, contractile responses to ACh were found to be significantly increased. We found that erythrocyte GPx activities were lower and erythrocyte superoxide dismutase activities were higher than in the control group. These data support the hypothesis that PAF produces free oxygen radicals and that HBO2 enhances this effect.

Animals↗

PubMed1998

Platelet aggregation and release function in hyperbaric oxygenation.

The aim of the study was to investigate the acute and chronic effects of hyperoxygenation on platelet aggregation and adenosine triphosphate (ATP) release. To observe the acute effects of hyperbaric oxygen (HBO2), seven New Zealand rabbits were exposed to 2.4 atm abs oxygen for 90 min (group 1). Eight other rabbits were further exposed to O2 daily for 20 days (group 2) to observe the chronic effects of HBO2. Adenosine diphophate (ADP) and collagen-induced platelet aggregation and ATP release were evaluated before and after oxygenation in groups 1 and 2. It was found that the maximal rate of ADP and collagen-induced platelet aggregation decreased after hyperbaric oxygenation in group 1. No significant alteration was observed in platelet responses at the end of 20 days of oxygenation in group 2. The adaptation of platelets of 2.4 atm abs O2 after 20 days of exposure seems to need further investigation.

Adenosine Diphosphate↗