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Maxime Mallet, Nicolas Weiss, Dominique Thabut, Marika Rudler
Hyperammonemia plays a key role in the pathophysiology of hepatic encephalopathy (HE) and most HE treatments are ammonia-lowering drugs. However, the usefulness of measuring ammonemia in routine practice remains controversial and not recommended systematically even when neurological symptoms are present. First, ammonemia measurement should be carefully performed in order to avoid a falsely elevated result. When performed, a normal ammonemia in a cirrhotic patient with neurological symptoms should lead to reconsider the diagnosis of HE...
March 15, 2018: Clinics and Research in Hepatology and Gastroenterology
Xiao-Li Xie, Jie-Tao He, Zheng-Tao Wang, Huan-Qin Xiao, Wen-Tao Zhou, Si-Hao Du, Ye Xue, Qi Wang
Methamphetamine (METH) is a widely abused psychostimulant. Lactulose is a non-absorbable sugar, which effectively decreases METH-induced neurotoxicity in rat. However, the exact mechanisms need further investigation. In this study, 5-week-old male Sprague Dawley rats received METH (15 mg/kg, 8 intraperitoneal injections, 12-hour interval) or saline and received lactulose (5.3 g/kg, oral gavage, 12-hour interval) or vehicle 2 days prior to the METH administration. Compared to the control group, in the METH alone group, cytoplasmic vacuolar degeneration in hepatocytes, higher levels of alanine transaminase, aspartate transaminase and ammonia, overproduction of reactive oxygen species (ROS) and increase of superoxide dismutase activity in the blood were observed...
March 14, 2018: Toxicology Letters
Karen Louise Thomsen, Francesco De Chiara, Krista Rombouts, Hendrik Vilstrup, Fausto Andreola, Rajeshwar P Mookerjee, Rajiv Jalan
Non-alcoholic fatty liver disease (NAFLD) is a spectrum of liver diseases ranging from steatosis, through non-alcoholic steatohepatitis (NASH) to cirrhosis. The development of fibrosis is the most important factor contributing to NASH-associated morbidity and mortality. Hepatic stellate cells (HSCs) are responsible for extracellular matrix deposition in conditions of frank hepatocellular injury and are key cells involved in the development of fibrosis. In experimental models and patients with NASH, urea cycle enzyme gene and protein expression is reduced resulting in functional reduction in the in vivo capacity for ureagenesis and subsequent hyperammonemia at a pre-cirrhotic stage...
April 2018: Medical Hypotheses
Nina Hediger, Markus A Landolt, Carmen Diez-Fernandez, Martina Huemer, Johannes Häberle
Neonatal onset hyperammonemia in patients with urea cycle disorders (UCDs) is still associated with high morbidity and mortality. Current protocols consistently recommend emergency medical and dietary management. In case of increasing or persistent hyperammonemia, with continuous or progressive neurological signs, dialysis is performed, mostly as ultima ratio. It is presently unknown whether the currently defined ammonia threshold (e.g., at 500 μmol/L) to start dialysis is useful to improve clinical outcome...
March 8, 2018: Journal of Inherited Metabolic Disease
Areeg El-Gharbawy, Jerry Vockley
Fatty acid oxidation disorders (FAODs) and carnitine shuttling defects are inborn errors of energy metabolism with associated mortality and morbidity due to cardiomyopathy, exercise intolerance, rhabdomyolysis, and liver disease with physiologic stress. Hypoglycemia is characteristically hypoketotic. Lactic acidemia and hyperammonemia may occur during decompensation. Recurrent rhabdomyolysis is debilitating. Expanded newborn screening can detect most of these disorders, allowing early, presymptomatic treatment...
April 2018: Pediatric Clinics of North America
Marshall L Summar, Nicholas Ah Mew
The urea cycle disorders are a group of inherited biochemical diseases caused by a complete or partial deficiency of any one of the enzymes or transport proteins required to convert toxic ammonia into urea and to produce arginine and citrulline. The clinical manifestations of these disorders are mostly the result of acute or chronic hyperammonemia, which affects the central nervous system. Affected individuals can also develop hepatic dysfunction. These disorders can present at any age from the immediate newborn to later in life...
April 2018: Pediatric Clinics of North America
Michel Tchan
The adult endocrinologist may be asked to consult on a patient for unexplained biochemical disturbances that could be caused by an underlying inborn error of metabolism. A genetic disorder is generally less likely to be the cause as these disorders are individually rare, however inborn errors of metabolism are collectively not infrequent and important to consider as they may be treatable and tragic outcomes avoided. Hyperammonemia or lactic acidosis are most often secondary markers of an acquired primary disease process, but they may be a clue to the presence of a genetic disorder...
March 1, 2018: Reviews in Endocrine & Metabolic Disorders
Monika Oláhová, Wan Hee Yoon, Kyle Thompson, Sharayu Jangam, Liliana Fernandez, Jean M Davidson, Jennifer E Kyle, Megan E Grove, Dianna G Fisk, Jennefer N Kohler, Matthew Holmes, Annika M Dries, Yong Huang, Chunli Zhao, Kévin Contrepois, Zachary Zappala, Laure Frésard, Daryl Waggott, Erika M Zink, Young-Mo Kim, Heino M Heyman, Kelly G Stratton, Bobbie-Jo M Webb-Robertson, Michael Snyder, Jason D Merker, Stephen B Montgomery, Paul G Fisher, René G Feichtinger, Johannes A Mayr, Julie Hall, Ines A Barbosa, Michael A Simpson, Charu Deshpande, Katrina M Waters, David M Koeller, Thomas O Metz, Andrew A Morris, Susan Schelley, Tina Cowan, Marisa W Friederich, Robert McFarland, Johan L K Van Hove, Gregory M Enns, Shinya Yamamoto, Euan A Ashley, Michael F Wangler, Robert W Taylor, Hugo J Bellen, Jonathan A Bernstein, Matthew T Wheeler
ATP synthase, H+ transporting, mitochondrial F1 complex, δ subunit (ATP5F1D; formerly ATP5D) is a subunit of mitochondrial ATP synthase and plays an important role in coupling proton translocation and ATP production. Here, we describe two individuals, each with homozygous missense variants in ATP5F1D, who presented with episodic lethargy, metabolic acidosis, 3-methylglutaconic aciduria, and hyperammonemia. Subject 1, homozygous for c.245C>T (p.Pro82Leu), presented with recurrent metabolic decompensation starting in the neonatal period, and subject 2, homozygous for c...
February 16, 2018: American Journal of Human Genetics
Yanhong Jin, Di Li, Shiying Lu, Han Zhao, Zhao Chen, Wei Hou, Benfang Helen Ruan
Human glutamate dehydrogenase (GDH) plays an important role in neurological diseases, tumor metabolism, and hyperinsulinism-hyperammonemia syndrome (HHS). However, there are very few inhibitors known for human GDH. Recently, Ebselen was reported to crosslink with Escherichia coli GDH at the active site cysteine residue (Cys321), but the sequence alignment showed that the corresponding residue is Ala329 in human GDH. To investigate whether Ebselen could be an inhibitor for human GDH, we cloned and expressed an N-terminal His-tagged human GDH in E...
February 22, 2018: Assay and Drug Development Technologies
Abbie L Speas, Sarah E Lyles, Kimberly A Wirth, Christine E Fahey, Kelvin Kow, Amandine T Lejeune, Rowan J Milner
OBJECTIVES: To establish the occurrence of increased plasma ammonia concentration after L-asparaginase (L-asp) administration in dogs with high-grade lymphoma or leukemia; to identify risk factors for the development of hyperammonemia after L-asp administration; and to determine occurrence of adverse events related to hyperammonemia. DESIGN: Prospective case controlled study of sequentially enrolled dogs between May 2011 and March 2012. SETTING: A university veterinary teaching hospital...
February 22, 2018: Journal of Veterinary Emergency and Critical Care
Jamie R Robinson, Patricia C Conroy, Daphne Hardison, Rizwan Hamid, Peter H Grubb, John B Pietsch, Harold N Lovvorn
OBJECTIVE: We aimed to clarify the impact of extracorporeal membrane oxygenation (ECMO) as a platform to drive hemodialysis (HD) for ammonia clearance on outcomes of neonates with severe hyperammonemia. STUDY DESIGN: All neonates treated for hyperammonemia at a single children's hospital between 1992 and 2016 were identified. Patient characteristics and outcomes were compared between those receiving medical management or ECMO/HD. RESULT: Twenty-five neonates were treated for hyperammonemia, of which 13 (52%) received ECMO/HD...
February 21, 2018: Journal of Perinatology: Official Journal of the California Perinatal Association
Zachary M Rossfeld, Nathan R Wright
No abstract text is available yet for this article.
February 20, 2018: Annals of Internal Medicine
Stephen M Picca
No abstract text is available yet for this article.
February 20, 2018: Annals of Internal Medicine
Bertrand Hermann, Dominique Thabut, Nicolas Weiss
No abstract text is available yet for this article.
February 20, 2018: Annals of Internal Medicine
Peter Nissen Bjerring, Esben Jannik Bjerrum, Fin Stolze Larsen
BACKGROUND: Liver failure results in hyperammonaemia, impaired regulation of cerebral microcirculation, encephalopathy and death. However, the key mediator that alters cerebral microcirculation remains unidentified. In this study we show that topical ammonium significantly increases periarteriolar adenosine tone on the brain surface of healthy rats and is associated with a disturbed microcirculation. METHODS: Cranial windows were prepared in anaesthetized Wistar rats...
February 13, 2018: Journal of Hepatology
N Pusterla, R Vin, C M Leutenegger, L D Mittel, T J Divers
A new enteric virus of adult horses, equine coronavirus (ECoV), has recently been recognized. It is associated with fever, lethargy, anorexia, and less frequently, colic and diarrhea. This enteric virus is transmitted via the feco-oral route and horses become infected by ingesting fecally contaminated feed and water. Various outbreaks have been reported since 2010 from Japan, Europe and the USA. While the clinical signs are fairly non-specific, lymphopenia and neutropenia are often seen. Specific diagnosis is made by the detection of ECoV in feces by either quantitative real-time PCR, electron microscopy or antigen-capture ELISA...
January 2018: Veterinary Journal
Lucas Taoro-Gonzalez, Yaiza M Arenas, Andrea Cabrera-Pastor, Vicente Felipo
BACKGROUND: Hyperammonemic rats reproduce the cognitive alterations of patients with hepatic encephalopathy, including altered spatial memory, attributed to altered membrane expression of AMPA receptor subunits in hippocampus. Neuroinflammation mediates these cognitive alterations. We hypothesized that hyperammonemia-induced increase in IL-1β in hippocampus would be responsible for the altered GluA1 and GluA2 membrane expression. The aims of this work were to (1) assess if increased IL-1β levels and activation of its receptor are responsible for the changes in GluA1 and/or GluA2 membrane expression in hyperammonemia and (2) identify the mechanisms by which activation of IL-1 receptor leads to altered membrane expression of GluA1 and GluA2...
February 8, 2018: Journal of Neuroinflammation
Yael Wilnai, Yair J Blumenfeld, Kristina Cusmano, Susan R Hintz, Deborah Alcorn, William E Benitz, William E Berquist, Jonathan A Bernstein, Ricardo O Castillo, Waldo Concepcion, Tina M Cowan, Kenneth L Cox, Deirdre J Lyell, Carlos O Esquivel, Margaret Homeyer, Louanne Hudgins, Melissa Hurwitz, Jonathan P Palma, Susan Schelley, Vishnu Priya Akula, Marshall L Summar, Gregory M Enns
PURPOSE OF STUDY: Patients with neonatal urea cycle defects (UCDs) typically experience severe hyperammonemia during the first days of life, which results in serious neurological injury or death. Long-term prognosis despite optimal pharmacological and dietary therapy is still poor. The combination of intravenous sodium phenylacetate and sodium benzoate (Ammonul®) can eliminate nitrogen waste independent of the urea cycle. We report attempts to improve outcomes for males with severe ornithine transcarbamylase deficiency (OTCD), a severe X-linked condition, via prenatal intravenous administration of Ammonul and arginine to heterozygous carrier females of OTCD during labor...
March 2018: Molecular Genetics and Metabolism
Jing Liu, Enkhchimeg Lkhagva, Hea-Jong Chung, Hyeon-Jin Kim, Seong-Tshool Hong
Ammonia is constantly produced as a metabolic waste from amino acid catabolism in mammals. Ammonia, the toxic waste metabolite, is resolved in the liver where the urea cycle converts free ammonia to urea. Liver malfunctions cause hyperammonemia that leads to central nervous system (CNS) dysfunctions, such as brain edema, convulsions, and coma. The current treatments for hyperammonemia, such as antibiotics or lactulose, are designed to decrease the intestinal production of ammonia and/or its absorption into the body and are not effective, besides being often accompanied by side effects...
January 28, 2018: Nutrients
Khanh Quynh N Nguyen, Patricia M Jones, Khushbu Patel
No abstract text is available yet for this article.
February 2018: Clinical Chemistry
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