Modeling air emissions from complex facilities at detailed temporal and spatial resolution: The Methane Emission Estimation Tool (MEET)

Recent attention to methane emissions from oil and gas infrastructure has increased interest in comparing measurements with inventory emission estimates. While measurement methods typically estimate emissions over a few periods that are seconds to hours in length, current inventory methods typically produce long-term average emission estimates. This temporal mis-alignment complicates comparisons and leads to underestimates in the uncertainty of measurement methods. This study describes a new temporally and spatially resolved inventory emission model (MEET), and demonstrates the model by application to compressor station emissions - the key facility type in midstream natural gas operations The study looks at three common facility measurement methods: tracer flux methods for measuring station emissions, the use of ethane-methane ratios for source attribution of basin-scale estimates, and the behavior of continuous monitoring for leak detection at stations. Simulation results indicate that measurement methods likely underestimate uncertainties in emission estimates by failing to account for the variability in normal facility emissions and variations in ethane/methane ratios. A tracer-based measurement campaign could estimate emissions outside the 95% confidence interval of annual emissions 30% of the time, while ethane/methane ratios could be mis-estimated by as much as 50%. Use of MEET also highlights the need to improve data reporting from measurement campaigns to better capture the temporal and spatial variation in observed emissions.

Metabolomic profiling of dietary-induced insulin resistance in the high fat-fed C57BL/6J mouse

The predictive ability of metabolic profiling to detect obesity-induced perturbations in metabolism has not been clearly established. Complex aetiologies interacting with environmental factors highlight the need to understand how specific manipulations alter metabolite profiles in this state. The aim of this study was to determine if targeted metabolomic profiling could be employed as a reliable tool to detect dietary-induced insulin resistance in a small subset of experimental animals (n = 10/treatment). Following weaning, male C57BL/6J littermates were randomly divided into two dietary groups: chow and high fat. Following 12 weeks of dietary manipulation, mice were fasted for 5 h prior to serum collection. The resultant high fat-fed animals were obese and insulin resistant as shown by a euglycaemic-hyperinsulinaemic clamp. Sera were analysed by proton nuclear magnetic resonance spectroscopy, and 46 known compounds were identified and quantified. Multivariate analysis by orthogonal partial least squares discriminant analysis, a projection method for class separation, was then used to establish models of each treatment. Models were able to predict class separation between diets with 90% accuracy. Variable importance plots revealed the most important metabolites in this discrimination to include lysine, glycine, citrate, leucine, suberate and acetate. These metabolites are involved in energy metabolism and may be representative of the perturbations taking place with insulin resistance. Results show metabolomics to reliably describe the metabolic effects of insulin resistance in a small subset of samples and are an initial step in establishing metabolomics as a tool to understand the biochemical signature of insulin resistance.

Environmental factors and not genotype influence the plasma level of interleukin-1 receptor antagonist in normal individuals

Cytokine production may be regulated by both genotypic (single nucleotide or tandem repeat polymorphisms) and non-genotypic factors relating to the environment and inherent biology (i.e. gender). Interleukin (IL)-1 is one of the body's most highly proinflammatory cytokines and is implicated in the pathophysiology of numerous diseases, but also in the maintenance of homeostasis in a number of tissues. The cytokine IL-1 receptor antagonist (IL-1Ra) is the competitive inhibitor of the IL-1 agonists IL-1alpha and IL-1beta. In vivo IL-1Ra was measured in a cohort of 200 + blood donors and the effect of the IL-1 gene polymorphisms, environmental and biological factors assessed. In this study, we observed that possession of particular alleles of 5 IL-1 gene polymorphisms (IL1A-889, IL1Alpha VNTR, IL1B -511, IL1B +3953 and the IL1RN VNTR) did not correlate with higher plasma IL-1Ra levels. Environmental factors such as smoking and non-steroidal anti-inflammatory drug ingestion were associated with higher in vivo IL-1Ra levels (P = 0.015 and 0.022, respectively), but biological factors such as gender, age and menstruation status did not have any impact upon in vivo IL-1Ra levels. Genotypic associations of IL-1 gene family polymorphisms with disease features may reflect characteristics of stressed rather than normal control circuits for cytokine production.

The Cost of Funerals

The cost of funerals in one funeral home was significantly associated with the year and whether the funeral included cremation or burial but not with the sex or age of the deceased, or cause of death.

Rapid hematopoietic recovery after multicycle high-dose chemotherapy: enhancement of filgrastim-induced progenitor-cell mobilization by recombinant human stem-cell factor

PURPOSE

To assess the mobilization potential and safety of recombinant human stem-cell factor (SCF) when coadministered with filgrastim to untreated women with poor-prognosis breast cancer.

PATIENTS AND METHODS

Eligible women had breast cancer with 10 or more positive axillary nodes, or estrogen receptor-negative tumor with 4 positive nodes, or stage III disease. Patients were randomized to receive SCF plus filgrastim or filgrastim alone. Filgrastim 12 microg/kg daily was administered for 6 days by continuous subcutaneous infusion. SCF was administered by daily subcutaneous injection at 5, 10, or 15 microg/kg concurrent with filgrastim for 7 days, or 10 microg/kg daily starting 3 days before filgrastim for a total of 10 days (SCF pretreatment). Apheresis was performed on days 5, 6, and 7 of filgrastim administration. Patients then had three cycles of epirubicin 200 mg/m2 and cyclophosphamide 4 g/m2 every 28 days, each supported by one third of the apheresis product.

RESULTS

Sixty-two women were treated. Greater yields occurred in patients who received SCF 10 microg/kg daily plus filgastim than those who received filgrastim alone (P=.013 for CD34+ cells; P=.07 for granulocyte-macrophage colony-forming cells [GM-CFCs]). The difference was more marked with SCF-pretreatment than concurrent SCF. Fewer aphereses were required to reach the predetermined target of peripheral-blood progenitor/stem cells (PBPCs) in women who received SCF. SCF was generally well tolerated. Hematologic recovery was rapid after each of the three cycles of chemotherapy. There was no difference in recovery between the different treatment groups.

CONCLUSION

Mobilization of PBPCs by filgrastim is significantly enhanced by coadministration of SCF, and commencing SCF before filgrastim can optimize this effect. SCF has the potential to reduce the number of aphereses required to collect a target number of PBPCs.

Comparative study of the pharmacokinetics and toxicity of high-dose epirubicin with or without dexrazoxane in patients with advanced malignancy

PURPOSE

We evaluated the toxicity and pharmacokinetics of the combination of dexrazoxane with epirubicin at dexrazoxane/epirubicin dose ratios of 5 to 9:1 in a controlled, crossover phase I study in patients with advanced malignancy.

PATIENTS AND METHODS

Thirty-eight patients with a variety of malignancies were enrolled. Assessable patients received two cycles of chemotherapy consisting of epirubicin alone and in combination with dexrazoxane. Comparisons were made between the toxicity and pharmacokinetics of epirubicin in the two treatment arms, using each patient as his or her own control. Dexrazoxane and epirubicin were delivered at dose levels of 600/120 mg/m2, 900/120 mg/m2, 900/135 mg/m2, 900/150 mg/m2, and 1,200/135 mg/m2, respectively. Twenty-six patients completed two cycles of chemotherapy and were therefore assessable.

RESULTS

The maximum-tolerated doses (MTDs) of dexrazoxane/epirubicin were 1,200/135 mg/m2, with the dose-limiting toxicities being neutropenia, infection, and stomatitis. There was no difference in the nadir neutrophil or platelet counts between single-agent and combination treatment at any of the dose levels. Severe vomiting and stomatitis occurred less frequently following administration of epirubicin and dexrazoxane when compared with epirubicin alone (P = .01 and .02, respectively). Prior administration of higher doses (900 mg/m2 and 1,200 mg/m2) of dexrazoxane increased the systemic clearance of epirubicin, resulting in a decrease in the area under the curve (AUC). Elimination half-life, maximum plasma concentration (Cmax), and apparent volume of distribution of epirubicin were not significantly affected by dexrazoxane. Left ventricular ejection fraction (LVEF) decreased by greater than 10% in two patients, but neither developed clinical or radiologic evidence of cardiac failure.

CONCLUSION

This study demonstrates that dexrazoxane can be safely combined with escalating doses of epirubicin at dose ratios of 5 to 9:1 without having an adverse impact on toxicity. Studies are need to determine the optimal dose ratio for cardioprotection and to explore further the pharmacokinetic interactions of the two drugs at increasing doses of epirubicin supported by hematopoietic growth factors.

Randomized study of the effect of midnight removal of urinary catheters

This study shows that removal of urinary catheters at midnight has several advantages over removal at 6 AM. The midnight group had a significantly greater initial voided volume and a longer time to first void than the equivalent 6 AM group. Advantages to midnight catheter removal also exist for nursing staff. Midnight tends to be less busy on the nursing unit compared with 6 AM, thus making it a preferable time for performance of routine tasks. Catheter removal at midnight also allows for convenient observation of patient voiding and assessment earlier in the day. This means that any necessary intervention can take place during working hours when more staff are on duty. There is also the potential for earlier discharge, with economic benefits related to shorter bed stay and more efficient discharge planning. We believe midnight catheter removal offers considerable benefits over the traditional 6 AM time on both general and urology units.

Randomised study of the effect of midnight versus 0600 removal of urinary catheters

A randomised controlled trial was undertaken to determine the effects of midnight removal of urinary catheters on patients' voiding patterns and subsequent discharge from hospital. Patients whose urinary catheters were removed at midnight showed a greater volume of initial void than those whose catheters were removed at the usual time of 0600. Removal of urinary catheters routinely at midnight permits earlier assessment of patients' voiding, which may allow for earlier discharge from hospital.