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

Improving the assessment of gestational age in a Zimbabwean population

Objectives: To evaluate the performance and the utility of using birthweight‐adjusted scores of Dubowitz and Ballard methods of estimating gestational age in a Zimbabwean population. Method: The Dubowitz and the Ballard methods of estimating gestational age were administered to 364 African newborn infants with a known last menstrual period (LMP) at Harare Maternity Hospital. Results: Both methods were good predictors of gestational age useful in differentiating term from pre‐term infants. Our regression line was Y(LMP gestational age)=23.814+0.301*score for the Dubowitz and Y(LMP gestational age)=24.493+0.420*score for the Ballard method. Addition of birthweight to the regression models improved prediction of gestational age; Y(LMP gestational age)=23.512+0.219*score+0.0015*grams for Dubowitz and Y(LMP gestational age)=24.002+0.292*score+0.0016*grams for Ballard method. Conclusions: We recommend the use of our birthweight‐adjusted maturity scales; the Dubowitz for studies of prematurity, and the Ballard for routine clinical practice.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/135611/1/ijgo7.pd

Microfacies, Depositional Environments, and Diagenesis of the Amapa Carbonates (paleocene-Middle Miocene), Foz Do Amazonas Basin, Offshore Ne Brazil

195 p.Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 1984.A total of 2,795 thin sections were studied, representing the carbonate section of 18 wells drilled in the Foz do Amazonas Basin, offshore northeast Brazil. The Amapa Formation (Paleocene-Middle Miocene) consists of a carbonate platform adjacent to a landward fluvio-deltaic system which periodically prograded over the platform. The latter became discontinuous in the central portion of the basin after the Oligocene, when transverse canyons were developed connecting the deltaic complex to the open sea.The Amapa carbonates have been divided into 22 distinct microfacies combined into two depositional models separated by a major unconformity. The paleoenvironmental reconstruction of model 1 (Paleocene to Early Eocene) consists of five juxtaposed microfacies classified into three environmental subdivisions. Model 2 (Middle Eocene to Middle Miocene) comprises 17 microfacies classified into seven subenvironments.A sequence of twelve diagenetic stages was established for model 1 based on textural relationships. The most important reservoir rocks in this model are due to primary porosity locally reduced by later cementation. These potential oil reservoirs, which locally reach 20% porosity consist of lagoonal deposits of dasycladacean calcarenites with common intraparticle and interparticle porosity. The diagenetic sequence determined for model 2 comprises 13 distinct events. The best reservoirs in this model are due to secondary porosity generated by both selective and nonselective dissolution, the underground freshwater circulation being the main control factor of porosity generation.In the basinwide diagenetic interpretation it is suggested that four episodes of sea level lowering disrupted the dynamic equilibrium existing between rivers and ocean, and triggered distinct reactivations of the groundwater system. These disruptions would have activated extensive underground circulations of freshwater through the carbonates, causing both porosity generation in the undersaturated zone and dolomitization in the mixed water zone.U of I OnlyRestricted to the U of I community idenfinitely during batch ingest of legacy ETD