Free Radical Status Research Articles

Circadian rhythm of white blood cell aggregation and free radical status in healthy volunteers.

Previous studies have demonstrated circadian rhythms in the onset of thrombotic events, which occur most commonly in the morning, and also in the fibrinolytic activity of the blood which has a peak in the evening and a trough in the morning. There has recently been increasing interest in the role of white blood cells (WBCs) and free radicals (FRs) in thrombosis. No one has yet investigated the potential circadian variation of WBC aggregation and FRs in humans. We studied the circadian rhythm of WBC aggregation and FR status in 10 healthy male volunteers. Six blood samples were collected at 4 hourly intervals from 12:00 (mid-day) until 08:00 the following morning. The volunteers carried out normal daily activities until 00:00 at which time they went to bed and they remained in bed until 08:00. The following were measured on each sample: WBC aggregation; thiobarbituric acid reactive substances (TBARs), plasma thiols (PSH), red cell lysate thiols (LSH), glutathione (GSH) and superoxide dismutase (SOD) which are all altered in the presence of FR activity. The following parameters demonstrated significant circadian rhythms, WBC aggregation p less than 0.001, TBARs p less than 0.015, PSH p less than 0.001, LSH p less than 0.002. WBC aggregation was lowest at 09:00 and highest at 00:00-04:00. TBARs and PSH both had a peak at 16:00 and a trough at 04:00. LSH had a peak at 12:00 and a trough at 08:00. As the behaviour of WBCs and FR status influence the flow properties of blood, a circadian rhythm in WBC function and FR status may contribute to the time of onset of thrombotic diseases. Moreover, with many studies being currently undertaken in this area, our work indicates the need to standardize sample times.

Zinc deficiency, ethanol, and myocardial ischemia affect lipoperoxidation in rats

The production of oxygen free radicals can be stimulated by excess iron, cadmium, nickel, and the like. Inversely, copper, zinc, and selenium inhibit production, either via their own action or via antiradical metalloenzymes. The study involved determining the effect of zinc deficiency combined with chronic ethanol administration on the status of blood and tissue free radicals, as well as on cardiac function in isolated, perfused rats' hearts. Animals were fed a basic diet containing residual zinc at 0.2-0.3 ppm. Following a zinc deficiency lasting 5 wk, which during the last 4 wk was accompanied by chronic ethanol administration, hearts were submitted to ischemia for 30 min in vitro, followed by reperfusion. Biochemical analyses (zinc, superoxide dismutase, malondialdehyde, conjugated dienes, and so on) were performed in the blood and in the homogenates of different organs. The experimental zinc deficiency caused a slight decrease of superoxide dismutase activity, accompanied by increased production of peroxidated lipids. Ethanol administration appeared to increase the levels of peroxidated lipids in the heart. Finally, the combination of zinc deficiency and ethanol administration had very harmful effects, especially on lipid peroxidation and contractile function of the isolated, perfused heart in preischemic conditions.

Is There a Diurnal Variation in Free Radical and Anti-Oxidant Status in Healthy Man

Is There a Diurnal Variation in Free Radical and Anti-Oxidant Status in Healthy Man

Towards optimisation of the use of 1.02-MHz ultrasound to harvest vacuole-located secondary product from in vitro grown plant cells

The effect of 1.02-MHz continuous wave ultrasound on the kinetics of pigment release from in vitro grown red beetroot cells has been studied in relation to the dissolved gas content and free-radical status of the aqueous-based media used to support cells during sonication. Data presented here show that pigment release from sonicated cells was mediated by cavitational events generated within the support medium alone, and that cavitation-induced free-radicals were intimately associated with the process of product release. These findings are discussed with reference to the optimisation of the use of ultrasound to harvest intracellularly located solute from cultured plant cells, on a non-destructive basis.