Effects of oxidative stress on the erythrocyte Na+,K+ ATPase activity in female hyperthyroid patients

This study was planned to determine the effects of free-radical-induced damage on the Na+,K+-ATPase activity of erythrocytes during hyperthyroidism and 4 wk after propylthiouracil ( PTU) therapy (400 mg/d). The levels of plasma thiobarbituric acid-reactive substances (TBARS) as a marker of lipid peroxidation, erythrocyte glutathione ( GSH) concentration as an antioxidant, blood ATP concentration, and erythrocyte membrane Na+,K+-ATPase activity were determined in female hyperthyroid patients ( n = 22, mean age 40.5 +/-6.5 yr). Before the PTU therapy, plasma TBARS concentration was significantly higher and the levels of blood ATP and erythrocyte GSH and the activity of membrane Na+,K-(+)-ATPase were significantly lower in the hyperthyroid patients ( n = 15 women, mean age 40.8 +/-7.3 yr). Four weeks after PTU therapy, plasma TBARS concentration was decreased, and levels of erythrocyte GSH and blood ATP and of Na+,K+-ATPase activity of erythrocytes were elevated in the treated patients. There was a significant positive correlation between blood ATP concentration and Na+,K+-ATPase activity, and a negative correlation between plasma TBARS concentration and Na+,K+-ATPase activity before PTU. Our results might help to clarify the effects of the oxidative mechanisms on the erythrocyte membrane Na+,K+-ATPase activity in hyperthyroid patients

Effects of hormone replacement therapy on plasma nitric oxide and total thiol levels in postmenopausal women

Improvement in endothelial function may be an important mechanism by which hormone replacement therapy (HRT) protects postmenopausal women against coronary artery disease. Our aim was to assess the effects of HRT on plasma nitric oxide (NOx) (nitrate plus nitrite) and total thiols in postmenopausal women, as these parameters are associated with enhanced endothelial functions. Thirty-five healthy postmenopausal volunteers (mean age 50.5 +/- 4.7 yr) in an academic and hospital research environment were involved in the study. Blood samples were collected, one at baseline and the second after 6 mo of HRT. Plasma NOx and total thiol levels were significantly elevated in the subjects after HRT. NOx may be of importance in the protective effects of HRT. Further, the increase of plasma antioxidant thiol levels might also contribute to the beneficial effects of HRT

The effects of exposure of Co-60 on the oxidant/antioxidant status among radiation victims

This retrospective study has been performed with radiation victims who were accidentally exposed to a Co-60 source and its release into the environment. The aim of the study was to assess the effects of elevated radiation exposures on plasma level, on erythrocyte thio barbituric, acid reactive substance (TBARS) level and on erythrocyte glutathione (GSH) levels. Patients were treated in different hospitals with different symptoms such as nausea, vomiting, dizziness, along with severe anemia in some patients. Blood samples were collected 3-5 days following the radiation accident. Increases in plasma (6.25 +/- 0.90 nmol ml(-1)) and erythrocyte TBARS levels (330.5 +/- 30.5 mumol gHb(-1)) were found in comparison to a healthy group (3.72 +/- 0.68 nmol ml(-1) and 150.7 +/- 20.5 mumol gHb(-1), respectively) at a significant level (p<0.001). Erythrocyte GSH levels (5.2 +/- 0.30 mumol gHb(-1)) were found to be decreased among the victims (healthy-group: 10.2 +/- 0.7 mumol gHb(-1)) at the same significance level (p<0.001). These observations confirm a significant change induced by radiation in the oxidant/antioxidant status among the victims. It is suggested here that antioxidant supplementation therapy might be effective. in preventing the harmful effects of Co-60 radiation among radiation victims. (C) 2002 Elsevier Science Ltd. All rights reserved