ascorbic-acid and Apnea

We have investigated the influence of vitamin C diet supplementation on the antioxidant response and nitrite levels in lymphocytes and erythrocytes during diving apnea.. Seven male professional apnea divers participated in a double blind crossover study. Divers were randomly assigned to either vitamin C supplemented or placebo groups. The subjects did not take any other supplements than the ones provided for this study.. One group was supplemented with vitamin C capsules (1 g per day) for 7 days while the other group took a placebo composed of lactose. The usual dietary habits of participants were assessed using a self-reported 7-days 24-h recall before the day of the study. Blood samples were taken under basal conditions, immediately after diving apnea for 4 h and after 1 h of recovery.. Catalase activity increased in erythrocytes (23%) and superoxide dismutase increased in lymphocytes (35%) during the recovery only in the placebo group. Lymphocyte ascorbate levels increased in the supplemented group after diving (85%) and maintained high at recovery. Plasma nitrite levels increased about twofold in both groups during the recovery. Erythrocyte nitrite levels increased after diving (50%) and about twofold during the recovery in the supplemented group. Nitrite levels and iNOS levels in lymphocytes were higher in the placebo group than in the supplemented during the recovery. Erythrocyte carbonyl derivates were unchanged in all situations.. Vitamin C supplementation influenced the antioxidant response and NO handling in erythrocytes and lymphocytes to the oxidative stress induced by hypoxia-reoxygenation.

Topics: Antioxidants; Apnea; Ascorbic Acid; Catalase; Cell Hypoxia; Cross-Over Studies; Dietary Supplements; Diving; Double-Blind Method; Erythrocytes; Humans; Lymphocytes; Male; Nitric Oxide; Nitric Oxide Synthase Type II; Oxidation-Reduction; Oxidative Stress; Superoxide Dismutase

Oxidative stress induced by hypoxia/reoxygenation mediates the pathophysiological consequence of ischemia/reperfusion and human diseases. Diving apnea could be a good model of oxidative stress induced by hypoxia/reoxygenation. We studied the influence of vitamin C diet supplementation on the response of neutrophil antioxidant defenses, NO production, and redox status to diving apnea. Seven professional apnea divers participated in a double-blind cross study. Divers were assigned to either vitamin C-supplemented (1 g/d for a week) or placebo groups. Blood samples were taken under basal conditions, immediately after diving apnea for 4 h and after 1 h of recovery. Plasma vitamin C increased only in the supplemented group after diving and was maintained high in recovery. Diving apnea decreased neutrophil GSH/GSSG ratio in both groups, but maintained protein carbonyl derivates. Neutrophil catalase activity and levels and glutathione peroxidase activity were lower in the supplemented group than in the placebo group after diving. iNOS and nitrite levels decreased only in the supplemented group after diving and recovery. Diving apnea induced oxidative stress and initiated neutrophil reactions that resemble the acute-phase immune response with increased myeloperoxidase activity in neutrophils. Diet supplementation with vitamin C reduced neutrophil iNOS levels and NO production.

Topics: Antioxidants; Apnea; Ascorbic Acid; Catalase; Cell Hypoxia; Dietary Supplements; Diving; Humans; Male; Neutrophils; Nitric Oxide; Oxidation-Reduction; Oxidative Stress

Topics: Apnea; Ascorbic Acid; Coma; Diazepam; Drug Combinations; Humans; Psychomotor Disorders; Psychoses, Substance-Induced; Substance Withdrawal Syndrome; Substance-Related Disorders; Thioctic Acid; Vitamin B Complex

Topics: Anesthesia; Anesthesia, Intravenous; Anesthesiology; Apnea; Ascorbic Acid; Calcium; Gluconates; Humans; Muscles; Phenobarbital; Potassium; Sodium Chloride; Tetanus; Vitamin B Complex