A GAS-LIQUID SYSTEM FOR ENZYME KINETIC STUDIES OF VOLATILE ORGANIC CHEMICALS Determination of Enzyme Kinetic Constants and Partition Coefficients of Trichloroethylene

ABSTRACT: A gas-liquid system was developed for enzyme kinetic study wit

NMR-based metabolic characterization of chicken tissues and biofluids: a model for avian research

Introduction Poultry is one of the most consumed meat in the world and its related industry is always looking for ways to improve animal welfare and productivity. It is therefore essential to understand the metabolic response of the chicken to new feed formulas, various supplements, infections and treatments. Objectives As a basis for future research investigating the impact of diet and infections on chicken’s metabolism, we established a high-resolution proton nuclear magnetic resonance (NMR)-based metabolic atlas of the healthy chicken (Gallus gallus). Methods Metabolic extractions were performed prior to 1H-NMR and 2D NMR spectra acquisition on twelve biological matrices: liver, kidney, spleen, plasma, egg yolk and white, colon, caecum, faecal water, ileum, pectoral muscle and brain of 6 chickens. Metabolic profiles were then exhaustively characterized. Results Nearly 80 metabolites were identified. A cross-comparison of these matrices was performed to determine metabolic variations between and within each section and highlighted that only eight core metabolites were systematically found in every matrice. Conclusion This work constitutes a database for future NMR-based metabolomic investigations in relation to avian production and health

Absorption, Distribution, and Excretion of [\u3csup\u3e14\u3c/sup\u3eC]-3-Chloro-4 methylaniline Hydrochloride in Two Species of Birds Following a Single Oral Dose

Ring-labeled [14C]-3-chloro-4-methylaniline hydrochloride (250 μg per bird) was delivered to 21 red-winged blackbirds (Agelaius phoeniceus) and 21 dark-eyed juncos (Junco hyemalis) via oral gavage, and the distribution and excretion of radioactivity were determined at 15 and 30 min and 1, 4, 8, 12, and 24 h (n = 3 per time point). Direct measurement of radioactivity as well as measurement following combustion was accomplished using a liquid scintillation counter. Elimination from most tissues followed a two-compartment model, with very rapid elimination occurring between time 0 and 4 h and a much slower elimination phase occurring after that. The average half-life of elimination for the initial phase in most tissues examined was 0.16 h for juncos and 0.62 h for blackbirds. The average for the slower second phase of elimination was 3.4 h for juncos and 5.4 h for blackbirds. The radioactivity in blackbird kidney tissues did not change significantly for the duration of the test, pointing toward the kidney as a possible site of action for this important agricultural chemical

Recombinant Factor C (rFC) Assay and Gas Chromatography/Mass Spectrometry (GC/MS) Analysis of Endotoxin Variability in Four Agricultural Dusts

Endotoxin exposure is a significant concern in agricultural environments due to relatively high exposure levels. The goals of this study were to determine patterns of 3-hydroxy fatty acid (3-OHFA) distribution in dusts from four types of agricultural environments (dairy, cattle feedlot, grain elevator, and corn farm) and to evaluate correlations between the results of gas chromatography/mass spectrometry (GC/MS) analysis (total endotoxin) and biological recombinant factor C (rFC) assay (free bioactive endotoxin). An existing GC/MS-MS method (for house dust) was modified to reduce sample handling and optimized for small amount ( dairy (0.53) > corn farm (0.33) > grain elevator (0.11). In livestock environments, both odd- and even-numbered carbon chain length 3-OHFAs correlated with rFC assay response. The GC/EI-MS method should be especially useful for identification of specific 3-OHFAs for endotoxins from various agricultural environments and may provide useful information for evaluating the relationship between bacterial exposure and respiratory disease among agricultural workers

Surgical Explantation After TAVR Failure

OBJECTIVES The aim of this study was to evaluate clinical characteristics, mechanisms of failure, and outcomes of transcatheter aortic valve replacement (TAVR) explantation. BACKGROUND Surgical explantation following TAVR may be required for structural valve degeneration, paravalvular leak, infection, or other reasons. However, in-depth data on indications and outcomes are lacking. METHODS Data from a multicenter, international registry (EXPLANT-TAVR) of patients who underwent TAVR explantation were reviewed retrospectively. Explantations performed during the same admission as initial TAVR were excluded. Clinical and echocardiographic outcomes were evaluated. Median follow-up duration was 6.7 months (interquartile range [IQR]: 1.0-18.8 months) after TAVR explantation and was 97.7% complete at 30 days and 86.1% complete at 1 year. RESULTS From November 2009 to September 2020, 269 patients across 42 centers with a mean age of 72.7 +/- 10.4 years underwent TAVR explantation. About one quarter (25.9%) were deemed low surgical risk at index TAVR, and median Society of Thoracic Surgeons risk at TAVR explantation was 5.6% (IQR: 3.2%-9.6%). The median time to explantation was 11.5 months (IQR: 4.0-32.4 months). Balloon-expandable and self-expanding or mechanically expandable valves accounted for 50.9% and 49.1%, respectively. Indications for explantation included endocarditis (43.1%), structural valve degeneration (20.1%), paravalvular leak (18.2%), and prosthesis-patient mismatch (10.8%). Redo TAVR was not feasible because of unfavorable anatomy in 26.8% of patients. Urgent or emergency cases were performed in 53.1% of patients, aortic root replacement in 13.4%, and 54.6% had concomitant cardiac procedures. Overall survival at last follow-up was 76.1%. In-hospital, 30-day, and 1-year mortality rates were 11.9%, 13.1%, and 28.5%, respectively, and stroke rates were 5.9%, 8.6%, and 18.7%, respectively. CONCLUSIONS The EXPLANT-TAVR registry reveals that surgical risks associated with TAVR explantation are not negligible and should be taken into consideration in the lifetime management of aortic stenosis. (J Am Coll Cardiol Intv 2021;14:1978-1991) (c) 2021 by the American College of Cardiology Foundation