Single Fasting Plasma Glucose Versus 75-g Oral Glucose-Tolerance Test in Prediction of Adverse Perinatal Outcomes::A Cohort Study

Background: There remains uncertainty regarding whether a single fasting glucose measurement is sufficient to predict risk of adverse perinatal outcomes. Methods: We included 12,594 pregnant women who underwent a 75-g oral glucose-tolerance test (OGTT) at 22–28 weeks' gestation in the Born in Guangzhou Cohort Study, China. Outcomes were large for gestational age (LGA) baby, cesarean section, and spontaneous preterm birth. We calculated the area under the receiver operator characteristic curves (AUCs) to assess the capacity of OGTT glucose values to predict adverse outcomes, and compared the AUCs of different components of OGTT. Results: 1325 women had a LGA baby (10.5%). Glucose measurements were linearly associated with LGA, with strongest associations for fasting glucose (odds ratio 1.37, 95% confidence interval 1.30–1.45). Weaker associations were observed for cesarean section and spontaneous preterm birth. Fasting glucose have a comparable discriminative power for prediction of LGA to the combination of fasting, 1 h, and 2 h glucose values during OGTT (AUCs, 0.611 vs. 0.614, P = 0.166). The LGA risk was consistently increased in women with abnormal fasting glucose (≥5.1 mmol/l), irrespective of 1 h or 2 h glucose levels. Conclusions: A single fasting glucose measurement performs comparably to 75-g OGTT in predicting risk of having a LGA baby

Response of methane production via propionate oxidation to carboxylated multiwalled carbon nanotubes in paddy soil enrichments

Carboxylated multiwalled carbon nanotubes (MWCNTs-COOH) have become a growing concern in terms of their fate and toxicity in aqueous environments. Methane (CH4) is a major product of organic matter degradation in waterlogged environments. In this study, we determined the effect of MWCNTs-COOH on the production of CH4 from propionate oxidation in paddy soil enrichments. The results showed that the methanogenesis from propionate degradation was accelerated in the presence of MWCNTs-COOH. In addition, the rates of CH4 production and propionate degradation increased with increasing concentrations of MWCNTs-COOH. Scanning electron microscopy (SEM) observations showed that the cells were intact and maintained their structure in the presence of MWCNTs-COOH. In addition, SEM and fluorescence in situ hybridization (FISH) images revealed that the cells were in direct contact with the MWCNTs and formed cell-MWCNTs aggregates that contained both bacteria and archaea. On the other hand, nontoxic magnetite nanoparticles (Fe3O4) had similar effects on the CH4 production and cell integrity as the MWCNTs-COOH. Compared with no nanomaterial addition, the relative abundances of Geobacter and Methanosarcina species increased in the presence of MWCNTs-COOH. This study suggests that MWCNTs-COOH exerted positive rather than cytotoxic effects on the syntrophic oxidation of propionate in paddy soil enrichments and affected the bacterial and archaeal community structure at the test concentrations. These findings provide novel insight into the consequences of nanomaterial release into anoxic natural environments