Phenotypic Drug Resistance Pattern and Mutation Characteristics of Mycobacterium tuberculosis from Different Body Fluids Among Extra Pulmonary Patients Presented in Selected Hospitals in Addis Ababa, Ethiopia.

Background: Drug resistance in tuberculosis poses challenges to both the control and prevention of the disease. The extent of resistance is not well known in developing countries, including Ethiopia. This study was conducted to determine the drug resistance patterns and mutation characteristics of Mycobacterium tuberculosis among extra pulmonary tuberculosis patients in selected health facilities in Addis Ababa. Material and Methods: A cross-sectional study was conducted from February 2022 to August 2022 in selected hospitals in Addis Ababa. Socio-demographic and clinical data were collected using structured questionnaire. Mycobacterium tuberculosis complex (MTBC) isolates were tested for phenotypic drug susceptibility patterns using the Mycobacterium growth indicator tube (MGIT) method for first-line drugs and mutation characteristics using the Line Probe Assay (LPA) method. The data were analyzed using: SPSS version 23, and a P-value ≤ 0.05 was considered statistically significant. Results: From a total of 308 patient samples from presumptive extra pulmonary patients, 44 (14.3%) were positive for MTBC. Any drug resistance was discovered in 25% of 44 MTBC isolates evaluated for five first-line drugs phenotypically, with isoniazid (INH) and pyrazinamide (PZA) resistance accounting for a greater proportion with 13.6% and 11.4% of the isolates, respectively. Two (4.5%) of the isolates were MDR-TB. Out of 44 isolates tested using the Geno Type MTBDRplus assay, 5 (11.4%) showed mutations at katG and 2 (4.5%) showed mutations in the rpoB genes. Conclusion: Both the phenotypic and genotypic drug susceptibility test results showed a high proportion of INH resistance. All INH resistance-conferring mutations were identified from katG gene. The overall prevalence of MDR-TB was also high. For early case detection and treatment, expanding diagnostic capacity for first-line DST is a vital step to limit further spread of drug resistant TB strains in the study area.

Burden of Mycobacterium tuberculosis and Associated Factors among Presumptive Extra pulmonary Tuberculosis Patients from Selected Health Facilities, Addis Ababa, Ethiopia.

Background: Extra pulmonary tuberculosis (EPTB) accounts for a significant proportion of tuberculosis (TB), a devastating disease of public health concern. The complexity of the cases, the involvement of many organs, resource constraints, and concerns regarding drug resistance make disease diagnosis and treatment difficult. This study aimed to determine the burden of tuberculosis and associated factors among presumptive EPTB patients in selected hospitals in Addis Ababa. Material and methods: A cross-sectional study was conducted from February to August 2022 in selected public hospitals in Addis Ababa. Those who attended the hospitals and were presumptively diagnosed as EPTB patient were included in the study. Sociodemographic and clinical data were collected using a semistructured questionnaire. The GeneXpert MTB/RIF assay, Mycobacterium Growth Indicator Tube (MGIT) culture, and solid culture using Löwenstein-Jensen (LJ) medium were used. The data were entered and analyzed using SPSS version 23, and a p-value ≤ 0.05 was considered as statistically significant. Results: From a total of 308 participants enrolled in this study, the measured burdens of extrapulmonary tuberculosis using the Xpert MTB/RIF assay, liquid culture, and solid culture were 54 (17.5%), 45 (14.6%), and 39 (12.7%), respectively. In this study, sex, contact history with known TB cases, having a purulent type of aspirate, and being HIV positive had statistically significant associations with EPTB. Conclusions: The burden of extrapulmonary tuberculosis among presumptive extrapulmonary tuberculosis cases was found to be significant. Sex, contact history with a known TB case, having apurulent type of aspirate, and being HIV positive were found to be associated with extrapulmonary tuberculosis infection. Strict adherence to the national tuberculosis diagnosis and treatment guidelines is important, while the true burden of the disease should be ascertained using standard diagnostic tests for better prevention and control interventions.

Species differences in phenobarbital-mediated UGT gene induction in rat and human liver microtissues.

Species differences in hepatic metabolism of thyroxine (T4) by uridine diphosphate glucuronosyl transferase (UGT) and susceptibility to thyroid hormone imbalance could underlie differences in thyroid carcinogenesis caused by hepatic enzyme inducers in rats and humans. To investigate this hypothesis we examined profiles of hepatic UGT induction by the prototypical CAR activator phenobarbital (PB) in rat and human liver 3D microtissues. The rationale for this approach was that 3D microtissues would generate data more relevant to humans. Rat and human liver 3D microtissues were exposed to PB over a range of concentrations (500 u M - 2000 u M) and times (24-96 hr). Microarray and proteomics analyses were performed on parallel samples to generate integrated differentially expressed gene (DEG) datasets. Bioinformatics analysis of DEG data, including CAR response element (CRE) sequence analysis of UGT promoters, was used to assess species differences in UGT induction relative to CAR-mediated transactivation potential. A higher proportion of human UGT promoters were found to contain consensus CREs compared to the rat homologs. UGTs 1a6, 2b17 and 2b37 were upregulated by PB in rat liver 3D microtissues, but unaltered in human liver 3D microtissues. By contrast, human UGTs 1A8, 1A10 and 2B10 showed higher levels of induction (RNA and /or protein) compared to the rat homologs. There was general concordance between the presence of CREs and the induction of UGT RNA. As UGT1A and 2B isoforms metabolise T4, these results suggest that differences in UGT induction could contribute to differential susceptibility to CAR-mediated thyroid carcinogenesis in rats and humans.

Cross-species comparison of CAR-mediated procarcinogenic key events in a 3D liver microtissue model.

Characterisation of the mode of action (MOA) of constitutive androstane receptor (CAR)-mediated rodent liver tumours involves measurement 5 key events including activation of the CAR receptor, altered gene expression, hepatocellular proliferation, clonal expansion and increased hepatocellular adenomas/carcinomas. To test whether or not liver 3D microtissues (LiMTs) recapitulate CAR- mediated procarcinogenic key events in response to the prototypical CAR activator phenobarbital (PB) we performed hepatocyte proliferation (LI%) analysis in rat and human LiMTs using a microTMA technology in conjunction with integrated transcriptomics (microarray) and proteomics analysis. The rationale for this approach was that LiMTs containing parenchymal and non-parenchymal cells (NPCs) are more physiologically representative of liver and thus would generate data more relevant to the in vivo situation. Rat and human LiMTs were treated with PB over a range of concentrations (500 uM - 2000 uM) and times (24 h - 96 h) in a dose-response/time-course analysis. There was a dose-dependent induction of LI% in rat LiMTs, however there was little or no effect of PB on LI% in human LiMTs. ATP levels in the rat and human LiMTs were similar to control in all of the PB treatments. There was also a dose- and time-dependent PB-mediated RNA induction of CAR regulated genes CYP2B6/Cyp2b2, CYP3A7/Cyp3a9 and UGT1A6/Ugt1a6 in human and rat LiMTs, respectively. These CAR regulated genes were also upregulated at the protein level. Ingenuity pathways analysis (IPA) indicated that there was a significant (Z score >2.0;-log p value >) activation of CAR by PB in both human and rat LiMTs. These results indicate that human and rat LiMTs showed the expected responses at the level of PB-induced hepatocyte proliferation and enzyme induction with rat LiMTs showing significant dose-dependent effects while human LiMTs showed no proliferation response but did show dose-dependent enzyme induction at the RNA and protein levels. In conclusion LiMTs serve as a model to provide mechanistic data for 3 of the 5 key events considered necessary to establish a CAR-mediated MOA for liver tumourigenesis and thus can potentially reduce the use of animals when compiling mechanistic data packages.

Integrated metabolic models for xenobiotic induced mitochondrial toxicity in skeletal muscle.

There is a need for robust in vitro models to sensitively capture skeletal muscle adverse toxicities early in the research and development of novel xenobiotics. To this end, an in vitro rat skeletal muscle model (L6) was used to study the translation of transcriptomics data generated from an in vivo rat model. Novel sulfonyl isoxazoline herbicides were associated with skeletal muscle toxicity in an in vivo rat model. Gene expression pathway analysis on skeletal muscle tissues taken from in vivo repeat dose studies identified enriched pathways associated with mitochondrial dysfunction, oxidative stress, energy metabolism, protein regulation and cell cycle. Mitochondrial dysfunction and oxidative stress were further explored using in vitro L6 metabolic models. These models demonstrated that the sulfonyl isoxazoline compounds induced mitochondrial dysfunction, mitochondrial superoxide production and apoptosis. These in vitro findings accurately concurred with the in vivo transcriptomics data, thereby confirming the ability of the L6 skeletal muscle models to identify relevant in vivo mechanisms of xenobiotic-induced toxicity. Moreover, these results highlight the sensitivity of the L6 galactose media model to study mitochondrial perturbation associated with skeletal muscle toxicity; this model may be utilised to rank the potency of novel xenobiotics upon further validation.

Non-muscle myosin IIB (Myh10) is required for epicardial function and coronary vessel formation during mammalian development.

The coronary vasculature is an essential vessel network providing the blood supply to the heart. Disruptions in coronary blood flow contribute to cardiac disease, a major cause of premature death worldwide. The generation of treatments for cardiovascular disease will be aided by a deeper understanding of the developmental processes that underpin coronary vessel formation. From an ENU mutagenesis screen, we have isolated a mouse mutant displaying embryonic hydrocephalus and cardiac defects (EHC). Positional cloning and candidate gene analysis revealed that the EHC phenotype results from a point mutation in a splice donor site of the Myh10 gene, which encodes NMHC IIB. Complementation testing confirmed that the Myh10 mutation causes the EHC phenotype. Characterisation of the EHC cardiac defects revealed abnormalities in myocardial development, consistent with observations from previously generated NMHC IIB null mouse lines. Analysis of the EHC mutant hearts also identified defects in the formation of the coronary vasculature. We attribute the coronary vessel abnormalities to defective epicardial cell function, as the EHC epicardium displays an abnormal cell morphology, reduced capacity to undergo epithelial-mesenchymal transition (EMT), and impaired migration of epicardial-derived cells (EPDCs) into the myocardium. Our studies on the EHC mutant demonstrate a requirement for NMHC IIB in epicardial function and coronary vessel formation, highlighting the importance of this protein in cardiac development and ultimately, embryonic survival.

Metabolomics dataset of PPAR-pan treated rat liver.

This article contains mass spectrometry (MS) data investigating small molecule changes as an effect of a triple peroxisome proliferator-activated receptor (PPAR-pan) agonist GW625019 in the liver as described in the manuscript (Ament et al., 2016) [1]. Samples were measured using gas chromatography-mass spectrometry (GC-MS) for total fatty acid content, and liquid chromatography-mass spectrometry (LC-MS) to measure intact lipids, carnitines and selected aqueous metabolites and eicosanoids. Data files comprise of Excel (Microsoft, WA, USA) spreadsheets of identified metabolites and their area ratio values for total fatty acids, carnitines, aqueous metabolites, and eicosanoids where the intensity of the analytes were normalised to the intensity of the internal standard. In the case of open profiling intact lipid data, the Excel file contains area ratio values of retention time and mass to charge ratio pairs; again, the area ratio values were calculated by normalising to the intensity of the internal standard. It should be noted that several metabolic changes are potentially indirect (secondary, tertiary and ensuing changes).

PPAR-pan activation induces hepatic oxidative stress and lipidomic remodelling.

The peroxisome proliferator-activated receptors (PPARs) are ligand activated nuclear receptors that regulate cellular homoeostasis and metabolism. PPARs control the expression of genes involved in fatty-acid and lipid metabolism. Despite evidence showing beneficial effects of their activation in the treatment of metabolic diseases, particularly dyslipidaemias and type 2 diabetes, PPAR agonists have also been associated with a variety of side effects and adverse pathological changes. Agonists have been developed that simultaneously activate the three PPAR receptors (PPARα, γ and δ) in the hope that the beneficial effects can be harnessed while avoiding some of the negative side effects. In this study, the hepatic effects of a discontinued PPAR-pan agonist (a triple agonist of PPAR-α, -γ, and -δ), was investigated after dietary treatment of male Sprague-Dawley (SD) rats. The agonist induced liver enlargement in conjunction with metabolomic and lipidomic remodelling. Increased concentrations of several metabolites related to processes of oxidation, such as oxo-methionine, methyl-cytosine and adenosyl-methionine indicated increased stress and immune status. These changes are reflected in lipidomic changes, and increased energy demands as determined by free fatty acid (decreased 18:3 n-3, 20:5 n-3 and increased ratios of n-6/n-3 fatty acids) triacylglycerol, phospholipid (decreased and increased bulk changes respectively) and eicosanoid content (increases in PGB2 and 15-deoxy PGJ2). We conclude that the investigated PPAR agonist, GW625019, induces liver enlargement, accompanied by lipidomic remodelling, oxidative stress and increases in several pro-inflammatory eicosanoids. This suggests that such pathways should be monitored in the drug development process and also outline how PPAR agonists induce liver proliferation.

Characterization of multidrug transporter-mediated efflux of avermectins in human and mouse neuroblastoma cell lines.

ABC transporters play an important role in the disposition of avermectins in several animal species. In this study the interactions of three key avermectins, abamectin, emamectin and ivermectin, with human and mouse homologues of MDR1 (ABCB1/Abcb1a) and MRP (ABCC/Abcc), transporters endogenously expressed by human SH-SY5Y and mouse N2a neuroblastoma cells were investigated. In both cell lines, retention of the fluorescent dye H33342 was found to be significantly increased in the presence of avermectins and cyclosporin A. These effects were shown to be unresponsive to the BCRP inhibitor Ko-143 and therefore MDR1/Mdr1-dependent. Avermectins inhibited MDR1/Mdr1a-mediated H33342 dye efflux, with apparent Ki values of 0.24±0.08 and 0.18±0.02µM (ivermectin); 0.60±0.07 and 0.56±0.02µM (emamectin) and 0.95±0.08 and 0.77±0.25µM (abamectin) in SH-SY5Y and N2a cells, respectively. There were some apparent affinity differences for MDR1 and Mdr1a within each cell line (affinity for ivermectin>emamectin≥abamectin, P<0.05 by One-Way ANOVA), but importantly, the Ki values for individual avermectins for human MDR1 or mouse Mdr1a were not significantly different. MK571-sensitive retention of GSMF confirmed the expression of MRP/Mrp efflux transporters in both cell lines. Avermectins inhibited MRP/Mrp-mediated dye efflux with IC50 values of 1.58±0.51 and 1.94±0.72µM (ivermectin); 1.87±0.57 and 2.74±1.01µM (emamectin) and 2.25±0.01 and 1.68±0.63µM (abamectin) in SH-SY5Y and N2a cells, respectively. There were no significant differences in IC50 values between individual avermectins or between human MRP and mouse Mrp. Kinetic data for endogenous human MDR1/MRP isoforms in SH-SY5Y cells and mouse Mdr1a/b/Mrp isoforms in N2a cells are comparable for the selected avermectins. All are effluxed at concentrations well above 0.05-0.1µM ivermectin detected in plasma (Ottesen and Campbell, 1994; Ottesen and Campbell, 1994) This is an important finding in the light of toxicity seen in the Mdr1-deficient animal models CF-1 mice, Mdr1ab (-/-) double knockout mice and Collie dogs. We also confirm MRP/Mrp-mediated avermectin transport in both N2a and SH-SY5Y cell lines.

Erbb2 is required for cardiac atrial electrical activity during development.

The heart is the first organ required to function during embryonic development and is absolutely necessary for embryo survival. Cardiac activity is dependent on both the sinoatrial node (SAN), which is the pacemaker of heart's electrical activity, and the cardiac conduction system which transduces the electrical signal though the heart tissue, leading to heart muscle contractions. Defects in the development of cardiac electrical function may lead to severe heart disorders. The Erbb2 (Epidermal Growth Factor Receptor 2) gene encodes a member of the EGF receptor family of receptor tyrosine kinases. The Erbb2 receptor lacks ligand-binding activity but forms heterodimers with other EGF receptors, stabilising their ligand binding and enhancing kinase-mediated activation of downstream signalling pathways. Erbb2 is absolutely necessary in normal embryonic development and homozygous mouse knock-out Erbb2 embryos die at embryonic day (E)10.5 due to severe cardiac defects. We have isolated a mouse line, l11Jus8, from a random chemical mutagenesis screen, which carries a hypomorphic missense mutation in the Erbb2 gene. Homozygous mutant embryos exhibit embryonic lethality by E12.5-13. The l11Jus8 mutants display cardiac haemorrhage and a failure of atrial function due to defects in atrial electrical signal propagation, leading to an atrial-specific conduction block, which does not affect ventricular conduction. The l11Jus8 mutant phenotype is distinct from those reported for Erbb2 knockout mouse mutants. Thus, the l11Jus8 mouse reveals a novel function of Erbb2 during atrial conduction system development, which when disrupted causes death at mid-gestation.

The functional diversity of essential genes required for mammalian cardiac development.

Genes required for an organism to develop to maturity (for which no other gene can compensate) are considered essential. The continuing functional annotation of the mouse genome has enabled the identification of many essential genes required for specific developmental processes including cardiac development. Patterns are now emerging regarding the functional nature of genes required at specific points throughout gestation. Essential genes required for development beyond cardiac progenitor cell migration and induction include a small and functionally homogenous group encoding transcription factors, ligands and receptors. Actions of core cardiogenic transcription factors from the Gata, Nkx, Mef, Hand, and Tbx families trigger a marked expansion in the functional diversity of essential genes from midgestation onwards. As the embryo grows in size and complexity, genes required to maintain a functional heartbeat and to provide muscular strength and regulate blood flow are well represented. These essential genes regulate further specialization and polarization of cell types along with proliferative, migratory, adhesive, contractile, and structural processes. The identification of patterns regarding the functional nature of essential genes across numerous developmental systems may aid prediction of further essential genes and those important to development and/or progression of disease.

Modulation of mitochondrial bioenergetics in a skeletal muscle cell line model of mitochondrial toxicity.

Mitochondrial toxicity is increasingly being implicated as a contributing factor to many xenobiotic-induced organ toxicities, including skeletal muscle toxicity. This has necessitated the need for predictive in vitro models that are able to sensitively detect mitochondrial toxicity of chemical entities early in the research and development process. One such cell model involves substituting galactose for glucose in the culture media. Since cells cultured in galactose are unable to generate sufficient ATP from glycolysis they are forced to rely on mitochondrial oxidative phosphorylation for ATP generation and consequently are more sensitive to mitochondrial perturbation than cells grown in glucose. The aim of this study was to characterise cellular growth, bioenergetics and mitochondrial toxicity of the L6 rat skeletal muscle cell line cultured in either high glucose or galactose media. L6 myoblasts proliferated more slowly when cultured in galactose media, although they maintained similar levels of ATP. Galactose cultured L6 cells were significantly more sensitive to classical mitochondrial toxicants than glucose-cultured cells, confirming the cells had adapted to galactose media. Analysis of bioenergetic function with the XF Seahorse extracellular flux analyser demonstrated that oxygen consumption rate (OCR) was significantly increased whereas extracellular acidification rate (ECAR), a measure of glycolysis, was decreased in cells grown in galactose. Mitochondria operated closer to state 3 respiration and had a lower mitochondrial membrane potential and basal mitochondrial O2 (•-) level compared to cells in the glucose model. An antimycin A (AA) dose response revealed that there was no difference in the sensitivity of OCR to AA inhibition between glucose and galactose cells. Importantly, cells in glucose were able to up-regulate glycolysis, while galactose cells were not. These results confirm that L6 cells are able to adapt to growth in a galactose media model and are consequently more susceptible to mitochondrial toxicants.

A metabolomics investigation of non-genotoxic carcinogenicity in the rat.

Non-genotoxic carcinogens (NGCs) promote tumor growth by altering gene expression, which ultimately leads to cancer without directly causing a change in DNA sequence. As a result NGCs are not detected in mutagenesis assays. While there are proposed biomarkers of carcinogenic potential, the definitive identification of non-genotoxic carcinogens still rests with the rat and mouse long-term bioassay. Such assays are expensive and time-consuming and require a large number of animals, and their relevance to human health risk assessments is debatable. Metabolomics and lipidomics in combination with pathology and clinical chemistry were used to profile perturbations produced by 10 compounds that represented a range of rat non-genotoxic hepatocarcinogens (NGC), non-genotoxic non-hepatocarcinogens (non-NGC), and a genotoxic hepatocarcinogen. Each compound was administered at its maximum tolerated dose level for 7, 28, and 91 days to male Fisher 344 rats. Changes in liver metabolite concentration differentiated the treated groups across different time points. The most significant differences were driven by pharmacological mode of action, specifically by the peroxisome proliferator activated receptor alpha (PPAR-α) agonists. Despite these dominant effects, good predictions could be made when differentiating NGCs from non-NGCs. Predictive ability measured by leave one out cross validation was 87% and 77% after 28 days of dosing for NGCs and non-NGCs, respectively. Among the discriminatory metabolites we identified free fatty acids, phospholipids, and triacylglycerols, as well as precursors of eicosanoid and the products of reactive oxygen species linked to processes of inflammation, proliferation, and oxidative stress. Thus, metabolic profiling is able to identify changes due to the pharmacological mode of action of xenobiotics and contribute to early screening for non-genotoxic potential.

Time and dose-dependent effects of phenobarbital on the rat liver miRNAome.

In a previous study we had shown that treatment of male Fischer rats with exogenous chemicals for three months resulted in prominent, mode-of-action dependent effects on liver microRNA (miRNA) (Koufaris et al., 2012). Here we investigated how the effects of chemicals on liver miRNA in male Fischer rats relate to the length and dose of exposure to phenobarbital (PB), a drug with multiple established hepatic effects. Importantly, although acute PB treatment (1-7 days) had significant effects on liver mRNA and the expected effects on the liver phenotype (transient hyperplasia, hepatomegaly, cytochrome P450 induction), limited effects on liver miRNA were observed. However, at 14 days of PB treatment clear dose-dependent effects on miRNA were observed. The main effect of PB treatment from days 1 to 90 on liver miRNA was found to be the persistent, progressive, and highly correlated induction of the miR-200a/200b/429 and miR-96/182 clusters, occurring after the termination of the xenobiotic-induced transient hyperplasia. Moreover, in agreement with their reported functions in the literature we found associations between perturbations of miR-29b and miR-200a/200b by PB with global DNA methylation and zeb1/zeb2 proteins respectively. Our data suggest that miRNA are unlikely to play an important role in the acute responses of the adult rodent liver to PB treatment. However, the miRNA responses to longer PB exposures suggest a potential role for maintaining liver homeostasis in response to sub-chronic and chronic xenobiotic-induced perturbations. Similar studies for more chemicals are needed to clarify whether the temporal and dose pattern of miRNA-toxicant interaction identified here for PB are widely applicable to other xenobiotics.

Hepatic microRNA profiles offer predictive and mechanistic insights after exposure to genotoxic and epigenetic hepatocarcinogens.

In recent years, accumulating evidence supports the importance of microRNAs in liver physiology and disease; however, few studies have examined the involvement of these noncoding genes in chemical hepatocarcinogenesis. Here, we examined the liver microRNA profile of male Fischer rats exposed through their diet to genotoxic (2-acetylaminofluorene) and epigenetic (phenobarbital, diethylhexylphthalate, methapyrilene HCL, monuron, and chlorendic acid) chemical hepatocarcinogens, as well as to non-hepatocarcinogenic treatments (benzophenone, and diethylthiourea) for 3 months. The effects of these treatments on liver pathology, plasma clinical parameters, and liver mRNAs were also determined. All hepatocarcinogens affected the expression of liver mRNAs, while the hepatic microRNA profiles were associated with the mode of action of the chemical treatments and corresponded to chemical carcinogenicity. The three nuclear receptor-activating chemicals (phenobarbital, benzophenone, and diethylhexylphthalate) were characterized by the highly correlated induction of the miR-200a/200b/429, which is involved in protecting the epithelial status of cells and of the miR-96/182 clusters. The four non-nuclear receptor-activating hepatocarcinogens were characterized by the early, persistent induction of miR-34, which was associated with DNA damage and oxidative stress in vivo and in vitro. Repression of this microRNA in a hepatoma cell line led to increased cell growth; thus, miR-34a could act to block abnormal cell proliferation in cells exposed to DNA damage or oxidative stress. This study supports the proposal that hepatic microRNA profiles could assist in the earlier evaluation and identification of hepatocarcinogens, especially those acting by epigenetic mechanisms.

Application of a Bayesian deconvolution approach for high-resolution (1)H NMR spectra to assessing the metabolic effects of acute phenobarbital exposure in liver tissue.

High-resolution (1)H NMR spectroscopy is frequently used in the field of metabolomics to assess the metabolites found in biofluids or tissue extracts to define a metabolic profile that describes a given biological process. In this study, we aimed to increase the utility of NMR-based metabolomics by using advanced Bayesian modeling of the time-domain high-resolution 1D NMR free induction decay (FID). The improvement over traditional nonparametric binning is twofold and associated with enhanced resolution of the analysis and automation of the signal processing stage. The automation is achieved by using a Bayesian formalism for all parameters of the model including the number of components. The approach is illustrated with a study of early markers of acute exposure to different doses of a well-characterized nongenotoxic hepatocarcinogen, phenobarbital, in rats. The results demonstrate that Bayesian deconvolution produces a better model for the NMR spectra that allows the identification of subtle changes in metabolic concentrations and a decrease in the expected false discovery rate compared with approaches based on "binning". These properties suggest that Bayesian deconvolution could facilitate the biomarker discovery process and improve information extraction from high-resolution NMR spectra.