Metabolism and Toxicity of Thioacetamide and Thioacetamide SOxide in Rat Hepatocytes

“This document is the Accepted Manuscript version of a Published Work that appeared in final form in Chemical Research in Toxicology, copyright © American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work see http://pubs.acs.org/doi/abs/10.1021/tx3002719The hepatotoxicity of thioacetamide (TA) has been known since 1948. In rats, single doses cause centrilobular necrosis accompanied by increases in plasma transaminases and bilirubin. To elicit these effects TA requires oxidative bioactivation leading first to its S-oxide (TASO) and then to its chemically reactive S,S-dioxide (TASO2) which ultimately modifies amine-lipids and proteins. To generate a suite of liver proteins adducted by TA metabolites for proteomic analysis, and to reduce the need for both animals and labeled compounds, we treated isolated hepatocytes directly with TA. Surprisingly, TA was not toxic at concentrations up to 50 mM for 40 hr. On the other hand, TASO was highly toxic to isolated hepatocytes as indicated by LDH release, cellular morphology and vital staining with Hoechst 33342/propidium iodide. TASO toxicity was partially blocked by the CYP2E1 inhibitors diallyl sulfide and 4-methylpyrazole, and was strongly inhibited by TA. Significantly, we found that hepatocytes produce TA from TASO relatively efficiently by back-reduction. The covalent binding of [14C]-TASO is inhibited by unlabeled TA which acts as a “cold-trap” for [14C]-TA and prevents its re-oxidation to [14C]-TASO. This in turn increases the net consumption of [14C]-TASO despite the fact that its oxidation to TASO2 is inhibited. The potent inhibition of TASO oxidation by TA, coupled with the back-reduction of TASO and its futile redox cycling with TA may help explain phenomena previously interpreted as “saturation toxicokinetics” in the in vivo metabolism and toxicity of TA and TASO. The improved understanding of the metabolism and covalent binding of TA and TASO facilitates the use of hepatocytes to prepare protein adducts for target protein identification

COVID-19 symptoms at hospital admission vary with age and sex: results from the ISARIC prospective multinational observational study

Background: The ISARIC prospective multinational observational study is the largest cohort of hospitalized patients with COVID-19. We present relationships of age, sex, and nationality to presenting symptoms. Methods: International, prospective observational study of 60 109 hospitalized symptomatic patients with laboratory-confirmed COVID-19 recruited from 43 countries between 30 January and 3 August 2020. Logistic regression was performed to evaluate relationships of age and sex to published COVID-19 case definitions and the most commonly reported symptoms. Results: ‘Typical’ symptoms of fever (69%), cough (68%) and shortness of breath (66%) were the most commonly reported. 92% of patients experienced at least one of these. Prevalence of typical symptoms was greatest in 30- to 60-year-olds (respectively 80, 79, 69%; at least one 95%). They were reported less frequently in children (≤ 18 years: 69, 48, 23; 85%), older adults (≥ 70 years: 61, 62, 65; 90%), and women (66, 66, 64; 90%; vs. men 71, 70, 67; 93%, each P < 0.001). The most common atypical presentations under 60 years of age were nausea and vomiting and abdominal pain, and over 60 years was confusion. Regression models showed significant differences in symptoms with sex, age and country. Interpretation: This international collaboration has allowed us to report reliable symptom data from the largest cohort of patients admitted to hospital with COVID-19. Adults over 60 and children admitted to hospital with COVID-19 are less likely to present with typical symptoms. Nausea and vomiting are common atypical presentations under 30 years. Confusion is a frequent atypical presentation of COVID-19 in adults over 60 years. Women are less likely to experience typical symptoms than men

Setting priorities and reducing risk

Master of ScienceNatural Resources and EnvironmentUniversity of Michiganhttp://deepblue.lib.umich.edu/bitstream/2027.42/114288/1/39015052046896.pd

Management of End-of-Life Vehicles (ELVs) in the US

This report seeks to provide a "snap-shot" detailing current management of end-of-life vehicles (ELVs) in the United States. The report is divided as follows: Chapter 1 - Introduction: Focused on estimating end-of-life vehicle (ELV) generation rates, identifying typical ELVs encountered and defining an "average" ("generic equivalent") ELV in terms of material composition. Chapter 2 - ELV Management Process Description: Providing a step-by-step description of ELV processing from initial dismantling to shredding of remaining "hulks" to subsequent recovery of metals, and finally, disposal of waste residues generated ("automotive shredder waste" - ASR). Chapter 3 - Environmental and Energy Burdens of ELVs: Detailing key environmental burdens in terms of ASR and scrap tires, along with elaboration of energy burdens associated with each stage of ELV processing. Chapter 4 - Economic Assessment: Estimating the value of "as is" ELVs, the business economics faced by key ELV processors and ASR landfill disposal costs. Chapter 5 - Legislation/Policy Analysis: Detailing pertinent ELV-related legislation and policy in Western Europe (where government plays a much more active role than in the US) as well as the US. Chapter 6 - Key Players in ELV Management: Identifying the general nature and composition of ELV processors (dismantlers, shredders and non-ferrous material processors), pertinent information regarding individual auto manufacturers, an outline of key technical and trade organizations and finally, discussion of the US Council for Automotive Research (USCAR) - the Big 3 automaker's collaborative research group which focuses on both technical and environmental issues. Chapter 7 - Key Areas/Issues in ELV Management: Identifying six key areas/issues at the current forefront of ELV management concerns/activities. Chapter 8 - Conclusionshttp://deepblue.lib.umich.edu/bitstream/2027.42/192065/1/CSS01-01.pdfDescription of CSS01-01.pdf : ReportSEL

Induction of drug metabolism by forskolin: the role of the pregnane X receptor and the protein kinase a signal transduction pathway

ABSTRACT An extract of the plant Coleus forskohlii has been used for centuries in Ayurvedic medicine to treat various diseases such as hypothyroidism, heart disease, and respiratory disorders. Additionally, complex herbal mixtures containing this extract are gaining popularity in United States for their putative "fatburning" properties. The active ingredient in C. forskohlii extract is the diterpene compound forskolin. Forskolin is a widely used biochemical tool that activates adenyl cyclase, thereby increasing intracellular concentration of cAMP and thus activating the protein kinase A (PKA) signal transduction pathway. We show herein that both forskolin and its nonadenyl cyclase-activating analog 1,9 dideoxyforskolin induce CYP3A gene expression in primary hepatocytes by functioning as agonists of the pregnane X receptor (PXR). We show that activation of PKA signaling potentiates PXR-mediated induction of CYP3A gene expression in cultured hepatocytes and increases the strength of PXR-coactivator protein-protein interaction in cell-based assays. Kinase assays show that PXR can serve as a substrate for catalytically active PKA in vitro. Our data provide important insights into the molecular mechanism of both the PKA-dependent and -independent effects of forskolin on the expression of drug-metabolizing enzymes in liver. Finally, our data suggest that herbal therapy with C. forskohlii extract should be approached cautiously due to the potential for herb-drug interactions in patients on combination therapy

Pregnane X Receptor Is SUMOylated to Repress the Inflammatory Response

Long-term treatment of patients with the macrolide antibiotic and prototypical activator of pregnane X receptor (PXR) rifampicin (Rif) inhibits the inflammatory response in liver. We show here that activation of the inflammatory response in hepatocytes strongly modulates SUMOylation of ligand-bound PXR. We provide evidence that the SUMOylated PXR contains SUMO3 chains, and feedback represses the immune response in hepatocytes. This information represents the first step in developing novel pharmaceutical strategies to treat inflammatory liver disease and prevent adverse drug reactions in patients experiencing acute or systemic inflammation. These studies also provide a molecular rationale for constructing a novel paradigm that uniquely defines the molecular basis of the interface between PXR-mediated gene activation, drug metabolism, and inflammation