36 research outputs found
Oestrogen metabolites in relation to isoprostanes as a measure of oxidative stress
Objective  Oestradiol (E2) and its metabolites 2-hydroxyoestrone (2-OHE1) and 16Α-hydroxyoestrone (16Α-OHE1) are thought to curtail the greater oxidative stress found in the development and progression of disease conditions including atherosclerosis. We related oestrogen levels to F 2a -isoprostane levels, a biomarker of oxidative stress. Design and participants  Data were obtained from 1647 women, aged 47–57 years, participating in the fifth annual follow-up of the Study of Women's Health Across the Nation (SWAN), a study of the menopausal transition. Measurements  Serum E2 and urinary 2-OHE1 and 16Α-OHE1 concentrations were determined by enzyme-linked immunosorbent assay (ELISA) and urinary F 2a -isoprostanes were measured by enzyme immunoassay (EIA). Results  F 2a -isoprostane concentrations were elevated in women who smoked, a behaviour associated with increased oxidative stress, but not in stages of the natural menopause. Mean F 2a -isoprostane concentrations among pre- and postmenopausal women who smoked were 1082 and 1064 pg/ml, respectively, values double those in pre- (343 pg/ml) and postmenopausal (379 pg/ml) nonsmoking women. 2-OHE1 and F 2a -isoprostane concentrations were positively and highly correlated (partial correlations Ρ Y|X  = 0·44 and Ρ Y|X  = 0·43 in pre- and postmenopausal women, respectively). Similarly, 16Α-OHE1 concentrations were positively and highly correlated with F 2a -isoprostane concentrations (Ρ Y|X  = 0·52 and Ρ Y|X  = 0·59 in pre- and postmenopausal women, respectively). E2 was significantly correlated with F 2a -isoprostanes only in postmenopausal women (Ρ Y|X  = 0·20). Associations were adjusted for age, body mass index (BMI), race/ethnicity, lipids, physical activity level and alcohol consumption. Conclusions  This study does not support the commonly held hypothesis that levels of endogenous E2 or its oestrone metabolites favourably modify oxidative stress by decreasing F2 a -isoprostane levels.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/74943/1/j.1365-2265.2007.03108.x.pd
Avaliação da ingestĂŁo dietĂ©tica de cálcio em indivĂduos adultos portadores de hipertensĂŁo arterial idiopática
Fibroblast Growth Factor 23 and Hypophosphatemia: A Case of Hypophosphatemia Along the Rickets-Osteomalacia Spectrum
Phosphorus is a key component of bone, and a deficiency results in poor mineralization along with other systemic symptoms of hypophosphatemia. Various causes of hypophosphatemia with renal wasting of phosphorus have been identified. These include the Fanconi syndrome, various genetic mutations of fibroblast growth factor 23 (FGF23) handling and the sodium/phosphate cotransporter, and those due to FGF23 secretion by mesenchymal tumors. Depending on the cause, vitamin D metabolism may also be impaired, which may amplify the deficiency in phosphorus and render treatment more challenging. Here, we report a case of hypophosphatemia and multiple stress fractures in a 20-year-old male college student living with chronic bone pain and anxiety about suffering further fractures. We further review the literature regarding this spectrum