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urea cycle defect

Louise Crowe, Vicki Anderson, Winita Hardikar, Avihu Boneh
Ornithine Trans-Carbamylase (OTC) deficiency is the most common disorder of the urea cycle. Cognitive impairments in skills such as attention and executive function have been reported in individuals with OTC deficiency who are managed with medication. In some cases, children undergo liver transplantation (LTx) to correct the metabolic defect. The metabolic and medical outcomes of LTx are generally good. However, little is known about the impacts on cognition. In this study, four children (three female) completed detailed neuropsychological batteries prior to (n = 6) and following LTx (n = 8 assessments)...
March 10, 2018: JIMD Reports
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
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
Sandra Sirrs, Fady Hannah-Shmouni, Stephen Nantel, James Neuberger, Eric M Yoshida
Transplantation is an established disease modifying therapy in selected children with certain inherited metabolic diseases (IMDs). Transplantation of hematopoietic stem cells or solid organs can be used to partially correct the underlying metabolic defect, address life threatening disease manifestations (such as neutropenia) or correct organ failure caused by the disease process. Much less information is available on the use of transplantation in adults with IMDs. Transplantation is indicated for the same IMDs in adults as in children...
February 1, 2018: Journal of Inherited Metabolic Disease
Teresa Cruz-Bustos, Evgeniy Potapenko, Melissa Storey, Roberto Docampo
Trypanosoma cruzi, the etiologic agent of Chagas disease, undergoes drastic metabolic changes when it transits between a vector and mammalian hosts. Amino acid catabolism leads to the production of ammonium (NH4+), which needs to be detoxified. However, T. cruzi does not possess a urea cycle, and it is unknown how intracellular levels of ammonium are controlled. In this work, we identified an intracellular ammonium transporter of T. cruzi (TcAMT) that localizes to acidic compartments (reservosomes, lysosomes)...
January 2018: MSphere
Muhittin Celik, Osman Akdeniz, Nezir Ozgun
AIM: Newborns with inborn errors of metabolism can present with hyperammonaemic coma. In this study, we evaluated the effect of peritoneal dialysis on plasma ammonium levels and on the short-term outcome in neonatal patients with urea cycle defects and organic acidaemia. METHODS: Data from infants with hyperammonaemia due to urea cycle defects or organic acidaemia treated with dialysis were collected and retrospectively analysed. The results of patient groups (group I, survived; and group II, died) were compared...
January 22, 2018: Nephrology
Marcell Crispim, Flávia Silva Damasceno, Agustín Hernández, María Julia Barisón, Ismael Pretto Sauter, Raphael Souza Pavani, Alexandre Santos Moura, Elizabeth Mieko Furusho Pral, Mauro Cortez, Maria Carolina Elias, Ariel Mariano Silber
Trypanosoma cruzi, the etiological agent of Chagas disease, consumes glucose and amino acids depending on the environmental availability of each nutrient during its complex life cycle. For example, amino acids are the major energy and carbon sources in the intracellular stages of the T. cruzi parasite, but their consumption produces an accumulation of NH4+ in the environment, which is toxic. These parasites do not have a functional urea cycle to secrete excess nitrogen as low-toxicity waste. Glutamine synthetase (GS) plays a central role in regulating the carbon/nitrogen balance in the metabolism of most living organisms...
January 2018: PLoS Neglected Tropical Diseases
D-J Reijngoud
Patients with an inborn error of metabolism (IEM) are deficient of an enzyme involved in metabolism, and as a consequence metabolism reprograms itself to reach a new steady state. This new steady state underlies the clinical phenotype associated with the deficiency. Hence, we need to know the flux of metabolites through the different metabolic pathways in this new steady state of the reprogrammed metabolism. Stable isotope technology is best suited to study this. In this review the progress made in characterizing the altered metabolism will be presented...
January 9, 2018: Journal of Inherited Metabolic Disease
Renee R Handley, Suzanne J Reid, Rudiger Brauning, Paul Maclean, Emily R Mears, Imche Fourie, Stefano Patassini, Garth J S Cooper, Skye R Rudiger, Clive J McLaughlan, Paul J Verma, James F Gusella, Marcy E MacDonald, Henry J Waldvogel, C Simon Bawden, Richard L M Faull, Russell G Snell
The neurodegenerative disorder Huntington's disease (HD) is typically characterized by extensive loss of striatal neurons and the midlife onset of debilitating and progressive chorea, dementia, and psychological disturbance. HD is caused by a CAG repeat expansion in the Huntingtin ( HTT ) gene, translating to an elongated glutamine tract in the huntingtin protein. The pathogenic mechanism resulting in cell dysfunction and death beyond the causative mutation is not well defined. To further delineate the early molecular events in HD, we performed RNA-sequencing (RNA-seq) on striatal tissue from a cohort of 5-y-old OVT73 -line sheep expressing a human CAG-expansion HTT cDNA transgene...
December 26, 2017: Proceedings of the National Academy of Sciences of the United States of America
Yafen Zhang, Qianchao Cao, Peng Hu, Haifeng Cui, Xiaoping Yu, Zihong Ye
BACKGROUND: Ustilago esculenta, a pathogenic basidiomycete fungus, infects Zizania latifolia to form edible galls named Jiaobai in China. The distinct growth conditions of U. esculenta induced Z. latifolia to form three different phenotypes, named male Jiaobai, grey Jiaobai and white Jiaobai. The aim of this study is to characterize the genetic and morphological differences that distinguish the two U. esculenta strains. RESULTS: In this study, sexually compatible haploid sporidia UeT14/UeT55 from grey Jiaobai (T strains) and UeMT10/UeMT46 from white Jiaobai (MT strains) were isolated...
December 6, 2017: BMC Microbiology
Belisa Parmeggiani, Carmen Regla Vargas
Inborn errors of metabolism (IEM) comprise a group of over 600 disorders, each with a specific metabolic impairment due to a genetic defect. Urea cycle disorders (UCD) are IEM that affect the nitrogen disposal system, leading to hyperammonemia and the accumulation of other toxic metabolites in tissues of affected patients. UCD arise from mutations in the genes coding any of the enzymes participating in the urea cycle, either directly or as regulators of this pathway, causing severe respiratory alkalosis. Considering that the exact mechanisms underlying the damage found in UCD, the purpose of this minireview is to obtain data and search for links between UCD and oxidative stress, a phenomenon common to several IEM...
February 2018: Clinica Chimica Acta; International Journal of Clinical Chemistry
Cinzia Papadia, Sylwia Osowska, Luc Cynober, Alastair Forbes
The amino acid L-citrulline (CIT) is safely used from the neonatal period onwards in those with urea cycle defects and carbamyl phosphate synthetase or ornithine transcarbamylase deficiencies, but several lines of enquiry indicate that it might have a much wider therapeutic role. When protein intake is low and there is a catabolic state, endogenous arginine (ARG) synthesis cannot fully be met and its supplementation can prove challenging, particularly in patients with critical and multisystem illness. Supplementary CIT could constitute a safer but still focused means of delivering ARG to endothelial and immune cells as CIT is efficiently recycled into these cells and as kidneys can convert CIT into ARG...
October 16, 2017: Clinical Nutrition: Official Journal of the European Society of Parenteral and Enteral Nutrition
Fang-Yuan Yuan, Ning Deng, Chih-Cheng Shih, Yi-Ting Tseng, Ting-Chang Chang, Kuan-Chang Chang, Ming-Hui Wang, Wen-Chung Chen, Hao-Xuan Zheng, Huaqiang Wu, He Qian, Simon M Sze
A nitridation treatment technology with a urea/ammonia complex nitrogen source improved resistive switching property in HfO2-based resistive random access memory (RRAM). The nitridation treatment produced a high performance and reliable device which results in superior endurance (more than 10(9) cycles) and a self-compliance effect. Thus, the current conduction mechanism changed due to defect passivation by nitrogen atoms in the HfO2 thin film. At a high resistance state (HRS), it transferred to Schottky emission from Poole-Frenkel in HfO2-based RRAM...
October 26, 2017: Nanoscale Research Letters
Yi Jiang, Mohammed Almannai, V Reid Sutton, Qin Sun, Sarah H Elsea
Urea cycle disorders (UCDs) are genetic conditions characterized by nitrogen accumulation in the form of ammonia and caused by defects in the enzymes required to convert ammonia to urea for excretion. UCDs include a spectrum of enzyme deficiencies, namely n-acetylglutamate synthase deficiency (NAGS), carbamoyl phosphate synthetase I deficiency (CPS1), ornithine transcarbamylase deficiency (OTC), argininosuccinate lyase deficiency (ASL), citrullinemia type I (ASS1), and argininemia (ARG). Currently, sodium phenylbutyrate and glycerol phenylbutyrate are primary medications used to treat patients with UCDs, and long-term monitoring of these compounds is critical for preventing drug toxic levels...
November 2017: Molecular Genetics and Metabolism
Michele Costanzo, Miriam Zacchia, Giuliana Bruno, Daniela Crisci, Marianna Caterino, Margherita Ruoppolo
BACKGROUND: Inherited metabolic disorders or inborn errors of metabolism are caused by deficiency of enzymatic activities in the catabolism of amino acids, carbohydrates, or lipids. These disorders include aminoacidopathies, urea cycle defects, organic acidemias, defects of oxidation of fatty acids, and lysosomal storage diseases. Inborn errors of metabolism constitute a significant proportion of genetic diseases, particularly in children; however, they are individually rare. Clinical phenotypes are very variable, some of them remain asymptomatic, others manifest metabolic decompensation in neonatal age, and others encompass mental retardation at later age...
July 2017: Kidney Diseases
Eduardo López-Corella, Isabel Ibarra-González, Cynthia Fernández-Lainez, Miguel Á Rodríguez-Weber, Sara Guillén-Lopez, Leticia Belmont-Martínez, David Agüero-Linares, Marcela Vela-Amieva
Ornithine transcarbamylase deficiency (OTCD) is an X-linked urea cycle defect associated with severe and usually fatal hyperammonemia. This study describes a patient with early onset lethal OTCD due to a known pathogenic variant (c.298+1G>A), as well as the novel autopsy finding of kernicterus with relatively low blood concentration of unconjugated bilirubin (UCB) (11.55 mg/dL). The patient was a full-term male with a family history of two previous male siblings who died as newborns after acute neurologic deterioration...
December 2017: Neuropathology: Official Journal of the Japanese Society of Neuropathology
Nigel F Delaney, Rohit Sharma, Laura Tadvalkar, Clary B Clish, Ronald G Haller, Vamsi K Mootha
McArdle disease and mitochondrial myopathy impair muscle oxidative phosphorylation (OXPHOS) by distinct mechanisms: the former by restricting oxidative substrate availability caused by blocked glycogen breakdown, the latter because of intrinsic respiratory chain defects. We applied metabolic profiling to systematically interrogate these disorders at rest, when muscle symptoms are typically minimal, and with exercise, when symptoms of premature fatigue and potential muscle injury are unmasked. At rest, patients with mitochondrial disease exhibit elevated lactate and reduced uridine; in McArdle disease purine nucleotide metabolites, including xanthine, hypoxanthine, and inosine are elevated...
August 1, 2017: Proceedings of the National Academy of Sciences of the United States of America
Maureen Evans, Helen Truby, Avihu Boneh
OBJECTIVES: To examine relationships between dietary intake, growth and body composition patterns in patients with inborn errors of intermediary protein metabolism and to determine a safe protein:energy ratio (P:E ratio) associated with optimal growth outcomes. STUDY DESIGN: Retrospective longitudinal data of growth and dietary intake in patients (n = 75) with isovaleric acidemia (IVA; n = 7), methylmalonic acidemia/propionic acidemia (MMA/PA; n = 14), urea cycle defects (UCD; n = 44), classical maple syrup urine disease (MSUD; n = 10) were collected...
September 2017: Journal of Pediatrics
Yuan Yan Sin, Phillipe R Price, Laurel L Ballantyne, Colin D Funk
Arginase-1 deficiency in humans is a rare genetic disorder of metabolism resulting from a loss of arginase-1, leading to impaired ureagenesis, hyperargininemia and neurological deficits. Previously, we generated a tamoxifen-inducible arginase-1 deficient mouse model harboring a deletion of Arg1 exons 7 and 8 that leads to similar biochemical defects, along with a wasting phenotype and death within two weeks. Here, we report a strategy utilizing the Clustered, Regularly Interspaced, Short Palindromic Repeats (CRISPR)/CRISPR-associated protein 9 (Cas9) system in conjunction with piggyBac technology to target and reincorporate exons 7 and 8 at the specific Arg1 locus in attempts to restore the function of arginase-1 in induced pluripotent stem cell (iPSC)-derived hepatocyte-like cells (iHLCs) and macrophages in vitro...
May 31, 2017: Scientific Reports
Dariusz Rokicki, Magdalena Pajdowska, Joanna Trubicka, Meow-Keong Thong, Elżbieta Ciara, Dorota Piekutowska-Abramczuk, Maciej Pronicki, Roman Sikora, Rijad Haidar, Mariusz Ołtarzewski, Ewa Jabłońska, Premala Muthukumarasamy, Pavai Sthaneswar, Chin-Seng Gan, Małgorzata Krajewska-Walasek, Rosalba Carrozzo, Daniela Verrigni, Michela Semeraro, Cristiano Rizzo, Roberta Taurisano, Bader Alhaddad, Reka Kovacs-Nagy, Tobias B Haack, Carlo Dionisi-Vici, Ewa Pronicka, Saskia B Wortmann
The urea cycle disorder carbamoyl phosphate synthetase I deficiency is an important differential diagnosis in the encephalopathic neonate. This intoxication type inborn error of metabolism often leads to neonatal death or severe and irreversible damage of the central nervous system, even despite appropriate treatment. Timely diagnosis is crucial, but can be difficult on routine metabolite level. Here, we report ten neonates from eight families (finally) diagnosed with CPS1 deficiency at three tertiary metabolic centres...
May 17, 2017: Clinica Chimica Acta; International Journal of Clinical Chemistry
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