Arkansas Childrens Hospital Research Institute

Little Rock, AR, United States

Arkansas Childrens Hospital Research Institute

Little Rock, AR, United States
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University of Arkansas and Arkansas Childrens Hospital Research Institute | Date: 2015-02-13

The present disclosure relates to acetaminophen protein adducts and methods of diagnosing acetaminophen toxicity using the acetaminophen protein adducts. The present disclosure provides acetaminophen (APAP)-protein adducts and methods of detecting acetaminophen-induced toxicity in a subject using APAP-protein adducts. One aspect of the present disclosure provides an APAP-protein adduct for diagnosing acetaminophen-induced toxicity. According to the present disclosure, the inventors have identified proteins that are modified by N-acetyl-pbenzoquinoneimine (NAPQI) in subjects with acetaminophen-induced toxicity. Non-limiting examples of proteins modified by NAPQI include betaine-homocysteine 5-methyltransferase 1, cytoplasmic aspartate aminotransferase, 1,4-alpha-glucan branching enzyme, formimidoyltransferase-cyclodeaminase, and dystrophin.

Macdonald L.J.,University of Arkansas for Medical Sciences | Graham J.G.,University of Arkansas for Medical Sciences | Kurten R.C.,University of Arkansas for Medical Sciences | Kurten R.C.,Arkansas Childrens Hospital Research Institute | Voth D.E.,University of Arkansas for Medical Sciences
Cellular Microbiology | Year: 2014

Summary: Intracellular bacterial pathogens often subvert apoptosis signalling to regulate survival of their host cell, allowing propagation of the bacterial population. Coxiella burnetii, the intracellular agent of human Q fever, inhibits host cell apoptosis through several mechanisms, including prevention of mitochondrial cytochrome c release, triggering of an anti-apoptotic transcriptional programme, and activation of pro-survival kinases. To control host cell survival, C.burnetii delivers effector proteins to the eukaryotic cytosol using a specialized Dot/Icm type IV secretion system (T4SS). Effectors are predicted to regulate activity of pro-survival host signalling proteins, such as Akt and cAMP-dependent protein kinase (PKA), to control infection. Here, we show that host PKA activity is required for C.burnetii inhibition of macrophage apoptosis. PKA is activated during infection and inhibits activity of the pro-apoptotic protein Bad via phosphorylation. Bad is also phosphorylated at an Akt-specific residue, indicating C.burnetii uses two kinases to fully inactivate Bad. Additionally, Bad and the tethering protein 14-3-3β colocalize at the C.burnetii parasitophorous vacuole (PV) membrane during infection, an event predicted to alter Bad promotion of apoptosis. Inhibiting PKA activity prevents Bad recruitment to the PV, but the protein is retained at the membrane during induction of apoptosis. Finally, PKA regulatory subunit I (RI) traffics to the PV membrane in a T4SS-dependent manner, suggesting a C.burnetii effector(s) regulates PKA-dependent activities. This study is the first to demonstrate subversion of host PKA activity by an intracellular bacterial pathogen to prevent apoptosis and survive within macrophages. © 2013 John Wiley & Sons Ltd.

Rank R.G.,Arkansas Childrens Hospital Research Institute | Whittum-Hudson J.A.,Wayne State University
Journal of Infectious Diseases | Year: 2010

In all animal models for chlamydial infection, there is strong evidence for immunity to reinfection; however, immunity is only complete (ie, preventing infection) in the short term. In the long term, animals are only partially immune (ie, they can be reinfected, but infections are usually abbreviated and less intense than the primary infection). This review will target the mechanisms responsible for long-term versus short-term immunity and explore the roles of various components of the host response in immunity to chlamydial genital infection. © 2010 by the Infectious Diseases Society of America. All rights reserved.

Berlinski A.,University of Arkansas for Medical Sciences | Berlinski A.,Arkansas Childrens Hospital Research Institute
Respiratory Care | Year: 2013

Background: Nebulized therapy is commonly used in spontaneously breathing tracheostomized patients, despite a lack of recommended devices and techniques. I compared albuterol dose delivered to a model of spontaneously breathing children with tracheostomy, using different nebulizers, tracheostomy tube sizes, inhalation techniques, and breathing patterns. Methods: A tracheostomy model was connected in series to a breathing simulator, with a filter interposed. I simulated the breathing patterns of a 16-month-old child and 12-year-old child, and tested tracheostomy tubes with internal diameters of 3.5 mm and 5.5 mm. Albuterol nebulizer solution (2.5 mg/3 mL) was used. A breath-enhanced nebulizer (Pari LC Plus), a breath-actuated nebulizer (AeroEclipse), and a nebulizer that continuously delivers aerosol (Up-Draft II Opti-Neb) were operated for 5 min at 6 L/min with wall air. The Up-Draft II was tested with T-piece and mask interfaces, with an extension tube, and with and without assisted breathing (every breath and every other breath). The amount of albuterol delivered was analyzed via spectrophotometry. Particle size distribution was measured with a cascade impactor. Results: The Pari LC Plus was more efficient than the Up-Draft II or AeroEclipse. Assisted breathing with the Up-Draft II with extension increased albuterol delivery with every other breath (second best device/configuration), being superior to every breath technique. Adding an extension tube increased delivered albuterol. T-piece was more efficient than mask. Breathing patterns with larger tidal volume increased albuterol delivery. Tracheostomy size had less impact on drug delivery. Mass median aerodynamic diameter decreased by 48-74% when passing through the tracheostomy tubes, and 0.8% of the nominal dose was deposited in the tracheostomy tube. Conclusions: Albuterol delivery in a model of spontaneously breathing children with tracheostomy is influenced by type of device and configuration, use of assisted breathing, breathing pattern, and tracheostomy tube size. Mass median aerodynamic diameter significantly decreases during passage through a tracheostomy tube. © 2013 Daedalus Enterprises.

Frye R.E.,Arkansas Childrens Hospital Research Institute
Translational psychiatry | Year: 2013

Autism spectrum disorder (ASD) has been associated with mitochondrial disease (MD). Interestingly, most individuals with ASD and MD do not have a specific genetic mutation to explain the MD, raising the possibility of that MD may be acquired, at least in a subgroup of children with ASD. Acquired MD has been demonstrated in a rodent ASD model in which propionic acid (PPA), an enteric bacterial fermentation product of ASD-associated gut bacteria, is infused intracerebroventricularly. This animal model shows validity as it demonstrates many behavioral, metabolic, neuropathologic and neurophysiologic abnormalities associated with ASD. This animal model also demonstrates a unique pattern of elevations in short-chain and long-chain acyl-carnitines suggesting abnormalities in fatty-acid metabolism. To determine if the same pattern of biomarkers of abnormal fatty-acid metabolism are present in children with ASD, the laboratory results from a large cohort of children with ASD (n=213) who underwent screening for metabolic disorders, including mitochondrial and fatty-acid oxidation disorders, in a medically based autism clinic were reviewed. Acyl-carnitine panels were determined to be abnormal if three or more individual acyl-carnitine species were abnormal in the panel and these abnormalities were verified by repeated testing. Overall, 17% of individuals with ASD demonstrated consistently abnormal acyl-carnitine panels. Next, it was determined if specific acyl-carnitine species were consistently elevated across the individuals with consistently abnormal acyl-carnitine panels. Significant elevations in short-chain and long-chain, but not medium-chain, acyl-carnitines were found in the ASD individuals with consistently abnormal acyl-carnitine panels-a pattern consistent with the PPA rodent ASD model. Examination of electron transport chain function in muscle and fibroblast culture, histological and electron microscopy examination of muscle and other biomarkers of mitochondrial metabolism revealed a pattern consistent with the notion that PPA could be interfering with mitochondrial metabolism at the level of the tricarboxylic-acid cycle (TCAC). The function of the fatty-acid oxidation pathway in fibroblast cultures and biomarkers for abnormalities in non-mitochondrial fatty-acid metabolism were not consistently abnormal across the subgroup of ASD children, consistent with the notion that the abnormalities in fatty-acid metabolism found in this subgroup of children with ASD were secondary to TCAC abnormalities. Glutathione metabolism was abnormal in the subset of ASD individuals with consistent acyl-carnitine panel abnormalities in a pattern similar to glutathione abnormalities found in the PPA rodent model of ASD. These data suggest that there are similar pathological processes between a subset of ASD children and an animal model of ASD with acquired mitochondrial dysfunction. Future studies need to identify additional parallels between the PPA rodent model of ASD and this subset of ASD individuals with this unique pattern of acyl-carnitine abnormalities. A better understanding of this animal model and subset of children with ASD should lead to better insight in mechanisms behind environmentally induced ASD pathophysiology and should provide guidance for developing preventive and symptomatic treatments.

Frye R.E.,Arkansas Childrens Hospital Research Institute
Journal of Pediatric Neurology | Year: 2012

The recent scientific literature has documented an association between autism and mitochondrial dysfunction, yet the majority of reported cases of individuals with autism and mitochondrial disease have not reported a specific genetic defect to explain the cause of the mitochondrial dysfunction. Here we report two boys with regressive-type autism with similar biochemical, electron microscopy and electron transport chain abnormalities consistent with a mitochondrial disorder. Both boys manifested rare mutations in evolutionarily conserved regions of the cytochrome b gene, a gene that codes for an important component of complex III - one of the essential electron transport chain complexes. Only one of these mutations has been previously reported, making these mutations novel. Electron transport chain studies in two boys within this report are consistent with dysfunction of the electron transport chain beyond a complex III defect, consistent with other reports describing the effects of cytochrome b gene mutations. This report expands the knowledge of the etiology of mitochondrial dysfunction in children with autism. © 2012 - IOS Press and the authors. All rights reserved.

Berlinski A.,University of Arkansas for Medical Sciences | Berlinski A.,Arkansas Childrens Hospital Research Institute
Respiratory Care | Year: 2014

ACKGROUND: Patients with cystic fibrosis perform airway clearance techniques and receive nebulized medications on a regular basis. Some positive expiratory pressure (PEP) devices allow concomitant administration of aerosol. I hypothesized that this practice alters the aerosol characteristics and patient dose. I compared the aerosol characteristics and patient dose of nebulized albuterol from 2 types of nebulizer, alone and when connected to different PEP and vibratory PEP devices. METHODS: Three units of a continuous-output nebulizer (Up-Draft II Opti-Neb) and 3 units of a breath-enhanced nebulizer (LC Plus) were tested alone and connected to PEP devices (Acapella Choice, Acapella Duet, and EzPAP for Up-Draft II Opti-Neb, and Pari PEP at 2 different settings, and Pari PEP S system with the LC Plus). Aerosol characteristics were evaluated with a cooled cascade impaction technique. The nebulizers were loaded with 2.5 mg/3 mL albuterol solution and operated for 4 min at 6 L/min (wall air). Patient dose was evaluated with simulated breathing patterns for a child, small adult, and large adult. Albuterol was assayed via spectrophotometry. RESULTS: Connecting the LC Plus to the PEP devices did not change the aerosol characteristics or patient dose. Connecting the Up-Draft II Opti-Neb to the PEP devices significantly reduced the mass median aerodynamic diameter, from 4.13 μm to 3.72 μm with EzPAP (P =.02), 1.24 μm with Acapella Choice (P <.001), and 1.22 μm with Acapella Duet (P <.001). The total amount of albuterol captured by the impactor decreased when connected to either Acapella Choice (65%) or Acapella Duet (69%), with 17-25% retained in the PEP devices. Patient dose decreased by 76% and 84% when connected to Acapella Choice and Acapella Duet, respectively. CONCLUSIONS: Concomitant use of nebulizer and PEP or vibratory PEP devices that obstruct the aerosol pathway significantly decrease the aerosol particle size and the patient dose. © 2014 Daedalus Enterprises.

Frye R.E.,Arkansas Childrens Hospital Research Institute | Frye R.E.,University of Arkansas for Medical Sciences
Epilepsy and Behavior | Year: 2015

Autism spectrum disorder (ASD) affects a significant number of individuals in the United States, with the prevalence continuing to grow. A significant proportion of individuals with ASD have comorbid medical conditions such as epilepsy. In fact, treatment-resistant epilepsy appears to have a higher prevalence in children with ASD than in children without ASD, suggesting that current antiepileptic treatments may be suboptimal in controlling seizures in many individuals with ASD. Many individuals with ASD also appear to have underlying metabolic conditions. Metabolic conditions such as mitochondrial disease and dysfunction and abnormalities in cerebral folate metabolism may affect a substantial number of children with ASD, while other metabolic conditions that have been associated with ASD such as disorders of creatine, cholesterol, pyridoxine, biotin, carnitine, γ-aminobutyric acid, purine, pyrimidine, and amino acid metabolism and urea cycle disorders have also been associated with ASD without the prevalence clearly known. Interestingly, all of these metabolic conditions have been associated with epilepsy in children with ASD. The identification and treatment of these disorders could improve the underlying metabolic derangements and potentially improve behavior and seizure frequency and/or severity in these individuals. This paper provides an overview of these metabolic disorders in the context of ASD and discusses their characteristics, diagnostic testing, and treatment with concentration on mitochondrial disorders. To this end, this paper aims to help optimize the diagnosis and treatment of children with ASD and epilepsy. This article is part of a Special Issue entitled "Autism and Epilepsy". © 2014 The Authors.

Agency: Department of Health and Human Services | Branch: | Program: STTR | Phase: Phase II | Award Amount: 1.69M | Year: 2011

DESCRIPTION (provided by applicant): Acetaminophen (APAP) is the most commonly used drug for the treatment of pain and fever in the world today. In large doses, APAP causes acute liver failure and is the leading cause of acute liver failure in the US. Thecurrent laboratory test for the diagnosis of APAP toxicity, measurement of APAP levels in peripheral blood, is only effective in the first 24 hours of APAP overdose. Acetaminophen Toxicity Diagnostics (ATD), LLC has developed a rapid, point-of-care diagnostic assay (dipstick) for the measurement of APAP protein adducts. Adducts are sensitive and specific biomarkers of APAP hepatotoxicity that may be detected in peripheral blood 6 to 7 days after a toxic overdose of APAP. The dipstick detects APAP irreversibly bound to proteins (APAP protein adducts) by using antibodies specific for adducts in the detection system. The dipstick is reliable, accurate and provides rapid results. In Specific Aim 1, the dipstick will be calibrated to detect levels of APAP protein adducts corresponding to severe liver toxicity and 2000 precision manufactured, research use dipsticks will be produced. In Specific Aim 2, the dipsticks will be tested internally for stability, specificity, and diagnostic sensitivity using stored, frozen clinical samples. In Specific Aim 3, six major hepatology centers will participate in a study to measure dipstick performance in patients with acute liver injury and acute liver failure. Successful completion of these aims will establish the clinical utility of the dipstick, an innovation that will enhance the diagnosis of APAP toxicity. PUBLIC HEALTH RELEVANCE: Acetaminophen is the most widely used drug for the treatment of pain and fever around the world. Large doses of acetaminophen can cause acute liver failure and death. Diagnostic tests are needed for patients that have acetaminophen related liver injury. The current laboratory test only works in the first 24 hours after acetaminophen overdose. Acetaminophen Toxicity Diagnostics, LLC has developed a rapid dipstick test that measures biomarkers of acetaminophen liver injury. These biomarkers (known as acetaminophen protein adducts) can be measured in the blood samples of patients with acetaminophen related liver injury for 6 to 7 days after theoverdose. This project will further develop the dipstick test so that it can be available to physicians in the future.

Frye R.E.,Arkansas Childrens Hospital Research Institute
Journal of Child Neurology | Year: 2012

Both copy number changes in the 22q13 region and mitochondrial disease have been associated with autism spectrum disorder. In this report, for the first time, a girl with autism spectrum disorder is described who exhibits both mitochondrial disease and a 22q13.1-33 duplication. This child demonstrated hypotonia, developmental delays, growth deficiency, microcephaly, dysmorphic facial features, and white matter abnormalities, consistent with previous cases of 22q13 region duplication. The patient also demonstrated a unique pattern of electron transport chain abnormalities with marked decreases in complex II and II/III in fibroblasts and complex I/III and II/III in muscle tissue. The 22q13.1-33 region contains 6 genes associated with mitochondrial function. Thus, disruption of this chromosomal region could cause many of the clinical findings in this child through disruption of mitochondrial function. Therefore, a mitochondrial workup should be considered in individuals with copy number changes within the 22q13 region, such as those with Phelan-McDermid syndrome. © The Author(s) 2012.

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