Prevalence and Predictors of Compromised Bone Mineral Density in Pediatric Eosinophilic Esophagitis.

OBJECTIVES: The aim of the study was to determine whether patients with eosinophilic esophagitis (EoE) have lower bone mineral density (BMD) than expected and if bone deficits are more pronounced in subgroups of patients according to comorbidities (atopic disease and joint hypermobility) or treatments (dietary restriction, medication exposure). STUDY DESIGN: Retrospective chart review was performed to obtain clinical data, including length of diagnosis, comorbidities, and methods of treatment for patients with EoE ages 3 to 21 years who had a lumbar spine dual-energy x-ray absorptiometry scan performed between 2014 and 2017. BMD was standardized by calculation of age, sex, and race-specific z scores. RESULTS: A total of 269 patients met study criteria. The mean BMD z score (-0.55, 95% confidence interval: -0.68, -0.42) was lower than expected (P < 0.0001), and the prevalence of low BMD z score (≤-2.0) was higher than expected (8.5%, 95% confidence interval: 5.2%-11.9%, P < 0.0001). In multivariable regression models, BMD z scores were -0.27 lower among those following an elimination diet and -0.65 lower among those with any lifetime use of a proton pump inhibitor (93% of the sample). There was no association with swallowed steroid use. CONCLUSIONS: In our sample, pediatric patients with EoE had a slightly lower BMD z score compared to peers, and the prevalence of low BMD was higher than expected. Taken cautiously given the limitations of our sample, risk factors for bone deficits included any lifetime use of proton pump inhibitor and a restrictive elimination diet, but not swallowed steroid use. Larger prospective studies are needed to better characterize risk factors for low BMD to help inform screening, selection of therapies, and provide appropriate anticipatory guidance for patients with EoE.

Monitoring Eosinophilic Esophagitis Disease Activity With Blood Eosinophil Progenitor Levels.

OBJECTIVES: A minimally invasive biomarker to monitor disease activity is one of the greatest unmet clinical needs of the pediatric eosinophilic esophagitis (EoE) population. We aimed to determine whether circulating eosinophil progenitors (EoPs) could be used as a biomarker to identify pediatric patients with active EoE. METHODS: In a prospective observational study, peripheral blood samples, symptom history, and laboratory data were collected from pediatric patients undergoing endoscopy for evaluation of EoE on dietary therapy at Cincinnati Children's Hospital. Peripheral blood EoP level was determined by flow cytometry. RESULTS: Thirty-four children with active (n = 16) and inactive (n = 18) EoE were included in the analysis. EoP levels in the peripheral blood were 3-fold higher in patients with active EoE than inactive EoE (P < 0.0025). Blood absolute eosinophil count did not distinguish between active and inactive EoE (P = 0.16). A cut-off EoP level ≥17 accurately detected active disease in 79% of patients with 94.4% specificity and 62.5% sensitivity (area under the curve 0.81; P < 0.0024). Antihistamine use lowered the threshold EoP level to detect active EoE. CONCLUSIONS: This study suggests that blood EoP levels may be used as a biomarker to detect active EoE disease in patients undergoing food trials and potentially reduce the need for repeated endoscopies. Larger prospective studies are needed to investigate the effects of antihistamines and swallowed steroids on EoP mobilization into the peripheral blood and longitudinal studies to assess the performance of the assay in individual patients over time.

Electrophoretic mobility, catalytic rate, and activation energy of catalysis of single molecules of the enzyme ß-glucuronidase from Escherichia coli.

Single molecule assays were performed on the enzyme E. coli ß-glucuronidase using a capillary electrophoresis-based protocol. Electrophoretic mobility, catalytic rate and activation energy of catalysis were all found to be heterogeneous. The average mobility at 22°C was -1.1×10-8±0.1m2V-1s-1 (N=49) with a total range of -0.6 to -1.3×10-8m2V-1s-1. The range in electrophoretic mobility suggests that the differences in shape or charge of the individual molecules underlying the heterogeneity are likely minimal. The average catalytic rate at 22°C was 37,000±19,000min-1 (N=49) with a total range of 14,000 to 130,000min-1. Both of these properties were measured simultaneously for each of the molecules. There was a weak correlation (r2=0.43) between mobility and rate with the molecules with a less negative mobility having a tendency to have a higher rate. The average activation energy of catalysis, as determined by comparing rates at 22 and 35°C, was found to be 48±18kJmol-1 (N=7) with a total range of 18-66kJmol-1.

12-Channel Peltier array temperature control unit for single molecule enzymology studies using capillary electrophoresis.

Capillary electrophoresis has been used to demonstrate that individual molecules of a given enzyme support different catalytic rates. In order to determine how rate varies with temperature, and determine activation energies for individual ß-galactosidase molecules, a 12-channel Peltier array temperature control device was constructed where the temperature of each cell was separately controlled. This array was used to control the temperature of the central 30 cm of a 50 cm long capillary, producing a temperature gradient along its length. Continuous flow single ß-galactosidase molecule assays were performed allowing measurement of the catalytic rates at different temperatures. Arrhenius plots were produced and the distribution of activation energies for individual ß-galactosidase molecules was found to be 56 ± 10 kJ/mol with a range of 34-72 kJ/mol.

Electrophoretic heterogeneity limits the utility of streptavidin-ß-galactosidase as a probe in free zone capillary electrophoresis separations.

Single molecule assays were performed on streptavidin-ß-galactosidase using a capillary electrophoresis-based protocol in order to assess the suitability of single molecule ß-galactosidase assays for adaptation to the detection of single copies of target DNA. The conjugate was found to have a heterogeneous catalytic rate, showing an average rate of 44,000 ± 24,000 min(-1), which is similar to that of the unmodified enzyme. Electrophoretic mobility was also measured on individual molecules and determined to be -1.32 × 10(-4) ± 0.19 × 10(-4) cm(2)V(-1)s(-1). The variance in mobility was several times that reported for the unmodified enzyme. The electrophoretic heterogeneity was found to result in the formation of a broad window of peaks in the resultant electropherograms of free zone separations of small plugs of streptavidin-ß-galactosidase. This range of mobilities largely overlapped with that of the conjugate bound to primer and plasmid containing a target DNA sequence. This overlap suggests that the separation of free conjugate from that bound to target DNA, which is a requirement for application of the single enzyme molecule assay to the detection of target DNA sequences, is not plausible using free zone capillary electrophoresis.

Woodland-to-forest transition during prolonged drought in Minnesota after ca. AD 1300.

Interactions among multiple causes of ecological perturbation, such as climate change and disturbance, can produce "ecological surprises." Here, we examine whether climate-fire-vegetation interactions can produce ecological changes that differ in direction from those expected from the effects of climate change alone. To do so, we focus on the "Big Woods" of central Minnesota, USA, which was shaped both by climate and fire. The deciduous Big Woods forest replaced regional woodlands and savannas after the severity of regional fire regimes declined at ca. AD 1300. A trend toward wet conditions has long been assumed to explain the forest expansion, but we show that water levels at two lakes within the region (Wolsfeld Lake and Bufflehead Pond) were low when open woodlands were transformed into the Big Woods. Water levels were high instead at ca. 2240-795 BC when regional fire regimes were most severe. Based on the correlation between water levels and fire-regime severity, we infer that prolonged or repeated droughts after ca. AD 1265 reduced the biomass and connectivity of fine fuels (grasses) within the woodlands. As a result, regional fire severity declined and allowed tree populations to expand. Tree-ring data from the region show a peak in the recruitment of key Big Woods tree species during the AD 1930s drought and suggest that low regional moisture balance need not have been a limiting factor for forest expansion. The regional history, thus, demonstrates the types of counterintuitive ecosystem changes that may arise as climate changes in the future.

The desire for multiple pregnancy in male and female infertility patients.

BACKGROUND: It is apparent that many fertility patients consider multiple birth an ideal treatment outcome. We wished to evaluate the desire for multiple birth among patients, and the effect of patient demographics and recognition of the increased fetal risks of multiple pregnancy on this desire. METHODS: This was a prospective questionnaire study completed by 801 male and female infertility patients attending a tertiary level Canadian university fertility clinic. Two logistic regression analyses were performed with desire for multiple birth with next fertility treatment and recognition of the increased fetal risks of multiple pregnancy as the dependent variables. RESULTS: 41% of patients desired a multiple birth. Increasing duration of infertility or previous assisted reproductive treatment increased, and having previous children or recognition of the increased fetal risks decreased, this desire. Patient age or sex did not affect desire for multiple birth. Previous assisted reproductive treatment was associated with increased recognition of the fetal risks of multiple pregnancy. CONCLUSIONS: A significant proportion of fertility patients considers multiple birth an ideal treatment outcome. Recognition of the increased fetal risks of multiple pregnancy significantly reduced this desire. Patient education may play an important role in assisting physicians in the quest to reduce the contribution of assisted reproductive treatment to multiple births and their attending complications.