Gravistimulation of Pisum Sativum and Expression of the Cell Membrane Expansin Proteins

This thesis research investigates the regulation of gene expression in pea stems (Pisum sativum) after changes in orientation to gravity (gravistimulation). Specifically, this project examines the changes in extracellular soluble proteins due to gravistimulation in pea seedlings. This change in gravity alters the cellular growth pattern, which can be directly linked to enzymatic activity resulting in the expression of cell wall loosening proteins called expansins. This loosening of the cell wall matrix subsequently increases elasticity in growing cells, thus leading to an upward curvature of the stems. These changes in enzymatic activity and gene expression are crucial for the survival of plants when variations in environmental conditions occur. The methods utilized in this project were performed in order to determine whether or not expansin genes are up-regulated during gravistimulation, and if the pea expansin gene family is highly conserved throughout the plant kingdom. Proteins were first extracted from the cell walls of peas at various times during gravistimulation (0 hrs. - 48 hrs.) and analyzed using SDS PAGE. Standard molecular techniques were also utilized in which, 1) the probe used to identify the expansin genes was created using RT-PCR, 2) a DNA library for Pisum sativum was created and screened for the presence of expansin genes, 3) standard Northern blotting techniques were applied to pea RNA extracted at various times during gravistimulation (0 hrs. - 48 hrs.) The results of this thesis found that the cell wall expansin genes were probably up-regulated during specific times of gravistimulation (i.e. 24 hours). However, due to the degeneracy of the expansin probe there is the possibility that more than one gene is being hybridized, thus decreasing our confidence in these results. In conclusion, these experiments must be repeated with a more specific probe to determine whether expansins do indeed exist in Pisum sativum and if they are being up-regulated

Do maternal demographics and prenatal history impact the efficacy of betamethasone therapy for threatened preterm labor?

Background: Betamethasone (BMZ) is used to accelerate fetal lung maturation in women with threatened preterm birth, but its efficacy is variable and limited by the lack of patient individualization in its dosing and administration. To determine sources of variability and potential opportunities for individualization of therapy, the objective of this study was to evaluate maternal factors associated with development of neonatal respiratory distress syndrome (RDS) in a cohort of women who received betamethasone. Methods: This study prospectively enrolled women, gestational ages 23-34 weeks, who received betamethasone for threatened preterm birth. Maternal demographics, prenatal history, and neonatal outcomes were abstracted from hospital records. RDS was the primary outcome. Associations between RDS diagnosis and maternal demographics, prenatal history, and betamethasone dosing were evaluated in a case-control analysis and multivariable regression adjusted for gestational age at delivery. Secondary analyses limited the cohort to women who delivered within 1 or 2 weeks of betamethasone dosing. Results: Of 209 deliveries, 90 (43 %) resulted in neonatal RDS. Within the overall cohort and controlling for gestational age at birth, RDS was only associated with cesarean births compared to vaginal births (adjusted OR 1.17 [1.06-1.29]). Route of delivery was also the only significant factor related to RDS in the 83 neonates delivered within 7 days of BMZ dosing. However, among 101 deliveries within 14 days of betamethasone dosing and controlling for gestational age at birth, women who experienced preterm premature rupture of membranes (PPROM) had lower RDS rates than those without PPROM (57.9 % vs. 80.2 %, adjusted OR 0.81 [0.67-0.99]). Maternal age, BMI, race, and ethnicity were not associated with RDS in the regression models. Conclusions: Of maternal characteristics analyzed, only delivery by cesarean was associated with neonatal RDS after antenatal betamethasone use

Urinary Iodine, Perchlorate, and Thiocyanate Concentrations in U.S. Lactating Women

Background: Iodine is an essential micronutrient for thyroid hormone production. Adequate iodine intake and normal thyroid function are important during early development, and breastfed infants rely on maternal iodine excreted in breast milk for their iodine nutrition. The proportion of women in the United States of childbearing age with urinary iodine concentration (UIC) <50 μg/L has been increasing, and a subset of lactating women may have inadequate iodine intake. UIC may also be influenced by environmental exposure to perchlorate and thiocyanate, competitive inhibitors of iodine transport into thyroid, and lactating mammary glands. Data regarding UIC in U.S. lactating women are limited. To adequately assess the iodine sufficiency of lactating women and potential associations with environmental perchlorate and thiocyanate exposure, we conducted a multicenter, cross-sectional study of urinary iodine, perchlorate, and thiocyanate concentrations in healthy U.S. lactating women. Methods: Lactating women ≥18 years of age were recruited from three U.S. geographic regions: California, Massachusetts, and Ohio/Illinois from November 2008 to June 2016. Demographic information and multivitamin supplements use were obtained. Iodine, perchlorate, and thiocyanate levels were measured from spot urine samples. Correlations between urinary iodine, perchlorate, and thiocyanate levels were determined using Spearman's rank correlation. Multivariable regression models were used to assess predictors of urinary iodine, perchlorate, and thiocyanate levels, and UIC <100 μg/L. Results: A total of 376 subjects (≥125 from each geographic region) were included in the final analyses [mean (SD) age 31.1 (5.6) years, 37% white, 31% black, and 11% Hispanic]. Seventy-seven percent used multivitamin supplements, 5% reported active cigarette smoking, and 45% were exclusively breastfeeding. Median urinary iodine, perchlorate, and thiocyanate concentrations were 143 μg/L, 3.1 μg/L, and 514 μg/L, respectively. One-third of women had UIC <100 μg/L. Spot urinary iodine, perchlorate, and thiocyanate levels all significantly positively correlated to each other. No significant predictors of UIC, UIC <100 μg/L, or urinary perchlorate levels were identified. Smoking, race/ethnicity, and marital status were significant predictors of urinary thiocyanate levels. Conclusion: Lactating women in three U.S. geographic regions are iodine sufficient with an overall median UIC of 143 μg/L. Given ubiquitous exposure to perchlorate and thiocyanate, adequate iodine nutrition should be emphasized, along with consideration to decrease these exposures in lactating women to protect developing infants