Entity

Time filter

Source Type

Laval, Canada

Authier S.,CiToxLAB North America | Pugsley M.K.,Janssen Pharmaceutical | Curtis M.J.,Rayne Institute
Handbook of Experimental Pharmacology | Year: 2015

Evaluation of the effects of a drug on arterial blood pressure is important in nonclinical safety pharmacology assessment. Detecting large and obvious changes in blood pressure is an unchallenging task. Detecting small changes is more difficult, and interpretation of findings requires careful risk/benefit evaluation. Detecting subtle and small changes in blood pressure is important in particular with respect to increases, since blood pressure above the normal range is associated with increased risk of stroke and sudden cardiac death. Cardiovascular safety pharmacology has been preoccupied with drug-induced changes in the electrocardiogram, and by comparison, there has been little in the way of contemporaneous improvements in the level of complexity and sophistication involved in blood pressure assessment. Thus, it is important to understand the nature of drug-induced changes in blood pressure, appreciate the plethora of agents currently used clinically (and over the counter) that alter blood pressure and understand safety pharmacology study design in order to optimize assessment of a new chemical entity (NCE) or biologic agent in this context. © Springer-Verlag Berlin Heidelberg 2015. Source


Pannkuk E.L.,Georgetown University | Laiakis E.C.,Georgetown University | Mak T.D.,U.S. National Institute of Standards and Technology | Astarita G.,Georgetown University | And 6 more authors.
Metabolomics | Year: 2016

Introduction: Due to dangers associated with potential accidents from nuclear energy and terrorist threats, there is a need for high-throughput biodosimetry to rapidly assess individual doses of radiation exposure. Lipidomics and metabolomics are becoming common tools for determining global signatures after disease or other physical insult and provide a “snapshot” of potential cellular damage. Objectives: The current study assesses changes in the nonhuman primate (NHP) serum lipidome and metabolome 7 days following exposure to ionizing radiation (IR). Methods: Serum sample lipids and metabolites were extracted using a biphasic liquid–liquid extraction and analyzed by ultra performance liquid chromatography quadrupole time-of-flight mass spectrometry. Global radiation signatures were acquired in data-independent mode. Results: Radiation exposure caused significant perturbations in lipid metabolism, affecting all major lipid species, including free fatty acids, glycerolipids, glycerophospholipids and esterified sterols. In particular, we observed a significant increase in the levels of polyunsaturated fatty acids (PUFA)-containing lipids in the serum of NHPs exposed to 10 Gy radiation, suggesting a primary role played by PUFAs in the physiological response to IR. Metabolomics profiling indicated an increase in the levels of amino acids, carnitine, and purine metabolites in the serum of NHPs exposed to 10 Gy radiation, suggesting perturbations to protein digestion/absorption, biological oxidations, and fatty acid β-oxidation. Conclusions: This is the first report to determine changes in the global NHP serum lipidome and metabolome following radiation exposure and provides information for developing metabolomic biomarker panels in human-based biodosimetry. © 2016, Springer Science+Business Media New York. Source


Pannkuk E.L.,Georgetown University | Laiakis E.C.,Georgetown University | Authier S.,CiToxLAB North America | Wong K.,CiToxLAB North America | And 2 more authors.
Radiation Research | Year: 2015

Due to concerns surrounding potential large-scale radiological events, there is a need to determine robust radiation signatures for the rapid identification of exposed individuals, which can then be used to guide the development of compact field deployable instruments to assess individual dose. Metabolomics provides a technology to process easily accessible biofluids and determine rigorous quantitative radiation biomarkers with mass spectrometry (MS) platforms. While multiple studies have utilized murine models to determine radiation biomarkers, limited studies have profiled nonhuman primate (NHP) metabolic radiation signatures. In addition, these studies have concentrated on short-term biomarkers (i.e., <72 h). The current study addresses the need for biomarkers beyond 72 h using a NHP model. Urine samples were collected at 7 days postirradiation (2, 4, 6, 7 and 10 Gy) and processed with ultra-performance liquid chromatography (UPLC) quadrupole time-of-flight (QTOF) MS, acquiring global metabolomic radiation signatures. Multivariate data analysis revealed clear separation between control and irradiated groups. Thirteen biomarkers exhibiting a dose response were validated with tandem MS. There was significantly higher excretion of l-carnitine, l-acetylcarnitine, xanthine and xanthosine in males versus females. Metabolites validated in this study suggest perturbation of several pathways including fatty acid β oxidation, tryptophan metabolism, purine catabolism, taurine metabolism and steroid hormone biosynthesis. In this novel study we detected long-term biomarkers in a NHP model after exposure to radiation and demonstrate differences between sexes using UPLC-QTOF-MS-based metabolomics technology. © 2015 by Radiation Research Society. Source


Bassett L.,CiToxLAB North America | Troncy E.,University of Montreal | Robichaud A.,SCIREQ Scientific Respiratory Equipment Inc. | Schuessler T.F.,SCIREQ Scientific Respiratory Equipment Inc. | And 5 more authors.
Journal of Pharmacological and Toxicological Methods | Year: 2014

Introduction: A number of drugs in clinical trials are discontinued due to potentially life-threatening airway obstruction. As some drugs may not cause changes in core battery parameters such as tidal volume (Vt), respiratory rate (RR) or minute ventilation (MV), including measurements of respiratory mechanics in safety pharmacology studies represents an opportunity for design refinement. The present study aimed to test a novel non-invasive methodology to concomitantly measure respiratory system resistance (Rrs) and conventional respiratory parameters (Vt, RR, MV) in conscious Beagle dogs and cynomolgus monkeys. Methods: An Airwave Oscillometry system (tremoFlo; THORASYS Inc., Montreal, Canada) was used to concomitantly assess Rrs and conventional respiratory parameters before and after intravenous treatment with a bronchoactive agent. Respiratory mechanics measurements were performed by applying a short (i.e. 16s) single high frequency (19Hz) waveform at the subject's airway opening via a face mask. During measurements, pressure and flow signals were recorded. After collection of baseline measurements, methacholine was administered intravenously to Beagle dogs (n=6) and cynomolgus monkeys (n=4) at 8 and 68μg/kg, respectively. Results: In dogs, methacholine induced significant increases in Vt, RR and MV while in monkeys, it only augmented RR. A significant increase in Rrs was observed after methacholine administration in both species with mean percentage peak increases from baseline of 88 (53)% for dogs and 28 (16)% for cynomolgus monkeys. Conclusion: Airwave Oscillometry appears to be a promising non-invasive methodology to enable respiratory mechanics measurements in conscious large animals, a valuable refinement in respiratory safety pharmacology. © 2014 Elsevier Inc. Source


Zheng J.,University of Arkansas for Medical Sciences | Wang J.,University of Arkansas for Medical Sciences | Pouliot M.,CiToxLAB North America | Authier S.,CiToxLAB North America | And 3 more authors.
BMC Genomics | Year: 2015

Background: Although extensive studies have investigated radiation-induced injuries in particular gastrointestinal (GI) segments, a systematic comparison among the different segments on the basis of mode, magnitude and mechanism has not been reported. Here, a comparative study of segment-specific molecular and cellular responses was performed on jejunum, ileum and colon obtained at three time points (4, 7 and 12 days after irradiation) from non-human primate (Rhesus macaque) models exposed to 6.7 Gy or 7.4 Gy total body irradiation (TBI). Results: Pathway analysis on the gene expression profiles identified radiation-induced time-, dose- and segment-dependent activation of tumor necrosis factor α (TNFα) cascade, tight junction, apoptosis, cell cycle control/DNA damage repair and coagulation system signaling. Activation of these signaling pathways suggests that colon sustained the severest mucosal barrier disruption and inflammation, and jejunum the greatest DNA damage, apoptosis and endothelial dysfunction. These more pronounced alterations correlate with the high incidence of macroscopic pathologies that are observed in the colon after TBI. Compared to colon and jejunum, ileum was resistant to radiation injury. In addition to the identification a marked increase of TNFα cascade, this study also identified radiation induced strikingly up-regulated tight junction gene CLDN2 (196-fold after 7.4-Gy TBI), matrix degradation genes such as MMP7 (increased 11- and 41-fold after 6.7-Gy and 7.4-Gy TBI), and anoikis mediated gene EDA2R that mediate mucosal shedding and barrier disruption. Conclusions: This is the first systematic comparative study of the molecular and cellular responses to radiation injury in jejunum, ileum and colon. The strongest activation of TNFα cascades and the striking up-regulation of its down-stream matrix-dissociated genes suggest that TNFα modulation could be a target for mitigating radiation-induced mucosal barrier disruption. © 2015 Zheng et al. Source

Discover hidden collaborations