Changes in free radical generation and antioxidant capacity during ultramarathon foot race.

BACKGROUND: Exhaustive exercise has been implicated in the generation of reactive oxygen species, resulting in oxidative stress. We studied the effect of a long-distance, endurance exercise on oxidative stress parameters in athletes who participated in the ultramarathon race Spartathlon (246 km). MATERIALS AND METHODS: This study included 18 runners (16 men and 2 women) aged 42.8 +/- 1.4 years. Blood samples were obtained 24 h before (prerace), at the end (postrace) and 48 h after the end of the race (48 h postrace). We measured oxidative stress indices, including red cell glutathione, malonyldialdehyde and 8-iso-prostaglandin F(2a), as well as the total antioxidant capacity. RESULTS: 8-Iso-prostaglandin F(2a) level increased significantly at the end of the race, compared to prerace levels (up to 914.7 +/- 61.4 pg mL(-1) from 197.6 +/- 8.4 pg mL(-1)), and remained 2.5-fold increased over the baseline 48 h after the race (532.0 +/- 54.2 pg mL(-1), P < 0.000). The total antioxidant capacity of the athletes increased from a baseline of 289.6 +/- 9.0 micromol L(-1) to 358.7 +/- 11.0 micromol L(-1) immediately after the race and remained elevated 48 h later (350.6 +/- 7.6 micromol L(-1)) (P < 0.001). CONCLUSIONS: Prolonged exercise induces a marked response of oxidative stress biomarkers, which in part is compensated by serum ability to scavenge free radicals. Whether these changes have long-term negative effects in the organism needs further investigation.

Dramatic reduction of erythrocyte glucose-6-phosphate dehydrogenase activity in athletes participating in the ultradistance foot race "Spartathlon".

OBJECTIVE: To investigate the effect of a long-distance endurance exercise "Spartathlon" on erythrocyte glucose-6-phosphate dehydrogenase (G(6)PD) activity. MATERIAL AND METHODS: The study comprised 15 male runners, median age 36.5 years. Blood samples were obtained in the 15 min before the race and again within 15 min after the end of the race. Erythrocyte glutathione (GSH and GSSG) and plasma malonyldialdehyde were measured with HPLC methods, and total antioxidant capacity (TAC), total hyperoxides and G(6)PD activity with commercial kits. Lipids, uric acid and total bilirubin were determined with a clinical chemistry analyser. RESULTS: Total hyperoxides were found statistically reduced, whereas total bilirubin was measured elevated post-race. Interestingly, GSSG levels were found increased (167.3+/-12.0 versus 219.5+/-20.3 micromol/L; p<0.005) as well as GSSG/GSH ratio (16.0+/-1.3 versus 20.60+/-1.65; p<0.05) post-race. In contrast, G(6)PD activity was found remarkably decreased (8.72+/-3.10 versus 3.8+/-2.5 U/g Hb; p<0.0001) pre versus post the event. CONCLUSION: Red blood cell G(6)PD activity in athletes may be reduced post-race as a consequence of the modulation of NADP/NADPH levels and elevation of the erythrocyte GSSG, and especially GSSG/GSH ratio, resulting in an impairment of the hexose monophosphate shunt.

Maternal-neonatal retinol and alpha-tocopherol serum concentrations in Greeks and Albanians.

BACKGROUND: Vitamin A and E are required in physiological processes such as pregnancy and growth. AIM: To evaluate retinol and alpha-tocopherol serum levels in Greek and Albanian mothers and in their newborns. METHODS: Data concerned 1125 Greek and 898 Albanian mothers along with their newborns. Immediately after delivery, blood from the umbilical cord and from the mothers was collected into light-protected tubes. Retinol and alpha-tocopherol serum levels were measured with a reversed-phase HPLC method. A 60-d dietetic diary was kept by each woman during the last 2 mo of pregnancy. RESULTS: Retinol (1.3 +/- 0.1 micromol/l) and alpha-tocopherol (32.9 +/- 9.5 micromol/l) levels were estimated to be normal in Greek mothers and in most of their offspring (0.9 +/- 0.1 and 18.5 +/- 3.4 micromol/l, respectively). In contrast, in Albanian mothers, retinol concentration was found to be low (0.6 +/- 0.1 micromol/l), and in 1/3 significantly low (<0.45 micromol/l). Consequently, the vitamin was evaluated to be very low in their newborns (0.4 +/- 0.1 micromol/l), and in 1/2 extremely low. However, in 12% of the Albanian cord blood samples, retinol level was determined to be higher as compared with that of their mothers. alpha-Tocopherol was evaluated to be normal in most of the immigrant mothers (20.0 +/- 8.8 micromol/l) and low (<7.5 micromol/l) in 15% of their newborns. Vitamin A intake was found to be extremely low and vitamin E low (p < 0.05) in the Albanians. CONCLUSIONS: (a) The decreased vitamin A and vitamin E intake, and their low blood status in the Albanian mothers and in their newborns, could be due to their low socio-economic and nutritional status. (b) Immigrant Albanians, during their pregnancy, and their newborns should be "followed up", being at risk of developing symptoms from the very low levels of these lipid-soluble vitamins.