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Cerebrospinal Fluid and Central Nervous System Cytology. COWELL AND TYLER'S DIAGNOSTIC CYTOLOGY AND HEMATOLOGY OF THE DOG AND CAT 2020. [PMCID: PMC7151995 DOI: 10.1016/b978-0-323-53314-0.00014-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Devriendt N, Or M, Meyer E, Paepe D, Vallarino N, Bhatti SFM, de Rooster H. Comparative accuracy and precision of two commercial laboratory analyzers for the quantification of ammonia in cerebrospinal fluid. Vet Clin Pathol 2019; 49:119-124. [PMID: 31646658 DOI: 10.1111/vcp.12789] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2018] [Revised: 02/13/2019] [Accepted: 03/07/2019] [Indexed: 11/27/2022]
Abstract
BACKGROUND Hyperammonemia is one of the contributing factors of hepatic encephalopathy (HE). Although blood ammonia concentrations are frequently measured in patients suspected of HE, systemic levels do not necessarily reflect the amount of ammonia in the central nervous system. Measuring ammonia in cerebrospinal fluid (CSF) can help to understand HE better and potentially improve the diagnosis and follow-up of patients with HE. OBJECTIVES The objectives of this technical report were to evaluate the accuracy and precision of two commercial blood ammonia analyzers (Catalyst Dx, CatDX and Pocket Chem BA, PocBA) to measure CSF ammonia concentrations. METHODS A pool of normal equine CSF was spiked with concentrated ammonia, and a series of six spiked samples were measured in parallel with both CatDx and PocBA. RESULTS CatDx and PocBA data correlated excellently with but differed significantly from the spiked ammonia concentrations. These differences were smaller when ammonia CSF concentrations were measured with the PocBA than with the CatDx. In addition, values obtained with the PocBA were more precise than those measured with the CatDx, especially for low ammonia concentrations. CONCLUSION This in-house comparative study shows that ammonia concentrations in spiked equine CSF correlate well with those measured by two commercial blood ammonia analyzers. Nevertheless, concentrations obtained with the PocBA are more accurate and more precise than those obtained with the CatDx, making the former device the preferred choice for clinical veterinary applications.
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Affiliation(s)
- Nausikaa Devriendt
- Small Animal Department, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium
| | - Matan Or
- Small Animal Department, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium
| | - Evelyne Meyer
- Laboratory of Biochemistry, Department of Pharmacology, Toxicology and Biochemistry, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium
| | - Dominique Paepe
- Small Animal Department, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium
| | - Nicolas Vallarino
- Small Animal Department, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium
| | - Sofie F M Bhatti
- Small Animal Department, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium
| | - Hilde de Rooster
- Small Animal Department, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium
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Exchange-mode glutamine transport across CNS cell membranes. Neuropharmacology 2019; 161:107560. [PMID: 30853601 DOI: 10.1016/j.neuropharm.2019.03.003] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2018] [Revised: 02/28/2019] [Accepted: 03/02/2019] [Indexed: 12/18/2022]
Abstract
CNS cell membranes possess four transporters capable of exchanging Lglutamine (Gln) for other amino acids: the large neutral amino acid (LNAA) transporters LAT1 and LAT2, the hybrid basic amino acid (L-arginine (Arg), L-leucine (Leu)/LNAA transporter y+LAT2, and the L-alanine/L-serine/L-cysteine transporter 2 (ASCT2). LAT1/LAT2 and y+LAT2 are present in astrocytes, neurons and the blood brain barrier (BBB) - forming cerebral vascular endothelial cells (CVEC), while the location of ASCT2 in the individual cell types is a matter of debate. In the healthy brain, contribution of the exchangers to Gln shuttling from astrocytes to neurons and thus their role in controlling the conversion of Gln to the amino acid neurotransmitters l-glutamate (Glu) and γ-aminobutyric acid (GABA) and Gln flux across the BBB appears negligible as compared to the system A and system N uniporters. Insofar, except for the contribution of LAT1 to the maintenance of Gln homeostasis in the interstitial fluid (ISF), no well-defined CNS-specific function has been established for either of the three transporters in the healthy brain. The Gln-accepting amino acid exchangers appear to gain significance under conditions of excessive brain Gln load (glutaminosis). Excess Gln efflux across the BBB enhances influx into the brain of L-tryptophan (Trp). Excess of Trp is responsible for overloading the brain with neuroactive compounds: serotonin, kynurenic acid, quinolinic acid and/or oxindole, which contribute to neurotransmission imbalance accompanying hyperammonemia. In turn, alterations of y+LAT2-mediated Gln/Arg exchange and Arg uptake in astrocyte, modulate astrocytic nitric oxide synthesis and oxidative/nitrosative stress in ammonia-overexposed brain. This article is part of the issue entitled 'Special Issue on Neurotransmitter Transporters'.
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Strickland R, Tivers MS, Adamantos SE, Harcourt-Brown TR, Fowkes RC, Lipscomb VJ. Incidence and risk factors for neurological signs after attenuation of single congenital portosystemic shunts in 253 dogs. Vet Surg 2018; 47:745-755. [DOI: 10.1111/vsu.12925] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2017] [Revised: 01/10/2018] [Accepted: 03/02/2018] [Indexed: 01/15/2023]
Affiliation(s)
- Rhiannon Strickland
- Department of Clinical Science and Services; Royal Veterinary College, University of London; London United Kingdom
| | - Michael S. Tivers
- School of Veterinary Sciences; University of Bristol; Bristol United Kingdom
| | | | | | - Robert C. Fowkes
- Department of Comparative Biomedical Sciences; Royal Veterinary College, University of London; London United Kingdom
| | - Victoria J. Lipscomb
- Department of Clinical Science and Services; Royal Veterinary College, University of London; London United Kingdom
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Or M, Devriendt N, Kitshoff AM, Peremans K, Vandermeulen E, Paepe D, Polis I, Martlé V, de Rooster H. Ammonia concentrations in arterial blood, venous blood, and cerebrospinal fluid of dogs with and without congenital extrahepatic portosystemic shunts. Am J Vet Res 2017; 78:1313-1318. [DOI: 10.2460/ajvr.78.11.1313] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Landsberg G, Maďari A, Žilka N. Behavioural and Medical Differentials of Cognitive Decline and Dementia in Dogs and Cats. CANINE AND FELINE DEMENTIA 2017. [PMCID: PMC7121040 DOI: 10.1007/978-3-319-53219-6_2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/02/2022]
Abstract
Cognitive dysfunction syndrome (CDS) is a diagnosis of exclusion given that there is no specific diagnostic test or tool and that medical disorders can cause the same set of signs. The veterinary surgeon must first identify that signs are present, collect a full history and then perform a full physical examination and relevant diagnostic tests to rule out medical causes for the signs including blood and urine analysis, radiographs and diagnostic imaging such as magnetic resonance imaging (MRI) where indicated.
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Affiliation(s)
- Gary Landsberg
- North Toronto Veterinary Behaviour, Specialty Clinic, Thornhill, Ontario Canada
| | - Aladár Maďari
- Univ of Veterinary Medicine and Pharmacy, Small Animal Clinic, Košice, Slovakia
| | - Norbert Žilka
- Slovak Academy of Sciences, Institute of Neuroimmunology, Bratislava, Slovakia
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Lidbury JA, Cook AK, Steiner JM. Hepatic encephalopathy in dogs and cats. J Vet Emerg Crit Care (San Antonio) 2016; 26:471-87. [PMID: 27060899 DOI: 10.1111/vec.12473] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2014] [Revised: 11/04/2014] [Accepted: 11/07/2014] [Indexed: 12/29/2022]
Abstract
OBJECTIVE To comparatively review the pathogenesis, clinical presentation, diagnosis, and management of hepatic encephalopathy (HE) in dogs and cats. DATA SOURCES The Medline database was searched for articles related to HE in people, dogs, and cats. Articles published within the last 5 years were given special importance. HUMAN DATA SYNTHESIS The pathogenesis of HE is complex and incompletely understood, but ammonia appears to play a central role. Hyperammonemia leads to accumulation of glutamine in astrocytes, with subsequent astrocyte swelling and neurological dysfunction. The development of HE in patients with hepatic cirrhosis is a poor prognostic indicator. The fermentable disaccharide lactulose and the antimicrobial rifaximin are US Food and Drug Administration approved treatments for human HE. Severe protein restriction is no longer recommended for patients with this condition. VETERINARY DATA SYNTHESIS HE is often associated with portosystemic shunting in dogs and cats. Ammonia plays a central role in the pathogenesis of HE in dogs and cats, but other factors such as manganese and endogenous benzodiazepines may also contribute. Recently, a soy protein-based diet was found to be beneficial in treating canine HE. Severe dietary protein restriction is likely to be detrimental in affected animals. There have been no clinical trials of drugs routinely used in the management HE in veterinary medicine, but lactulose and antimicrobials such as metronidazole are well-established treatments. CONCLUSIONS HE is a potentially life-threatening condition that is probably underdiagnosed in companion animals. Although various treatment recommendations have been proposed, there is a lack of evidence in the veterinary literature regarding optimal strategies for the management of this condition. As our understanding of the pathogenesis of HE in dogs and cats evolves, novel diagnostic tests and therapeutic agents may become available.
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Affiliation(s)
- Jonathan A Lidbury
- Department of Veterinary Small Animal Clinical Sciences, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX, 77843
| | - Audrey K Cook
- Department of Veterinary Small Animal Clinical Sciences, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX, 77843
| | - Jörg M Steiner
- Department of Veterinary Small Animal Clinical Sciences, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX, 77843
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Tivers MS, Handel I, Gow AG, Lipscomb VJ, Jalan R, Mellanby RJ. Hyperammonemia and systemic inflammatory response syndrome predicts presence of hepatic encephalopathy in dogs with congenital portosystemic shunts. PLoS One 2014; 9:e82303. [PMID: 24392080 PMCID: PMC3879253 DOI: 10.1371/journal.pone.0082303] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2013] [Accepted: 10/22/2013] [Indexed: 12/29/2022] Open
Abstract
Hepatic encephalopathy (HE) is an important cause of morbidity and mortality in patients with liver disease. The pathogenesis of he is incompletely understood although ammonia and inflammatory cytokines have been implicated as key mediators. To facilitate further mechanistic understanding of the pathogenesis of HE, a large number of animal models have been developed which often involve the surgical creation of an anastomosis between the hepatic portal vein and the caudal vena cava. One of the most common congenital abnormalities in dogs is a congenital portosystemic shunt (cpss), which closely mimics these surgical experimental models of HE. Dogs with a cPSS often have clinical signs which mimic clinical signs observed in humans with HE. Our hypothesis is that the pathogenesis of HE in dogs with a cPSS is similar to humans with HE. The aim of the study was to measure a range of clinical, haematological and biochemical parameters, which have been linked to the development of HE in humans, in dogs with a cPSS and a known HE grade. One hundred and twenty dogs with a cPSS were included in the study and multiple regression analysis of clinical, haematological and biochemical variables revealed that plasma ammonia concentrations and systemic inflammatory response syndrome scores predicted the presence of HE. Our findings further support the notion that the pathogenesis of canine and human HE share many similarities and indicate that dogs with cPSS may be an informative spontaneous model of human HE. Further investigations on dogs with cPSS may allow studies on HE to be undertaken without creating surgical models of HE thereby allowing the number of large animals used in animal experimentation to be reduced.
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Affiliation(s)
- Mickey S. Tivers
- Department of Veterinary Clinical Sciences, Royal Veterinary College, Hatfield, Hertfordshire, United Kingdom
| | - Ian Handel
- Royal (Dick) School of Veterinary Studies and The Roslin Institute, The University of Edinburgh, Roslin, Midlothian, United Kingdom
| | - Adam G. Gow
- Royal (Dick) School of Veterinary Studies and The Roslin Institute, The University of Edinburgh, Roslin, Midlothian, United Kingdom
| | - Vicky J. Lipscomb
- Department of Veterinary Clinical Sciences, Royal Veterinary College, Hatfield, Hertfordshire, United Kingdom
| | - Rajiv Jalan
- UCL Institute for Liver and Digestive Health, UCL Medical School, London, United Kingdom
| | - Richard J. Mellanby
- Royal (Dick) School of Veterinary Studies and The Roslin Institute, The University of Edinburgh, Roslin, Midlothian, United Kingdom
- MRC Centre for Inflammation Research, University of Edinburgh, Edinburgh, United Kingdom
- * E-mail:
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Musteata M, Nicolescu A, Solcan G, Deleanu C. The 1H NMR profile of healthy dog cerebrospinal fluid. PLoS One 2013; 8:e81192. [PMID: 24376499 PMCID: PMC3871169 DOI: 10.1371/journal.pone.0081192] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2013] [Accepted: 10/17/2013] [Indexed: 12/14/2022] Open
Abstract
The availability of data for reference values in cerebrospinal fluid for healthy humans is limited due to obvious practical and ethical issues. The variability of reported values for metabolites in human cerebrospinal fluid is quite large. Dogs present great similarities with humans, including in cases of central nervous system pathologies. The paper presents the first study on healthy dog cerebrospinal fluid metabolomic profile using 1H NMR spectroscopy. A number of 13 metabolites have been identified and quantified from cerebrospinal fluid collected from a group of 10 mix breed healthy dogs. The biological variability as resulting from the relative standard deviation of the physiological concentrations of the identified metabolites had a mean of 18.20% (range between 9.3% and 44.8%). The reported concentrations for metabolites may be used as normal reference values. The homogeneity of the obtained results and the low biologic variability show that the 1H NMR analysis of the dog’s cerebrospinal fluid is reliable in designing and interpreting clinical and therapeutic trials in dogs with central nervous system pathologies.
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Affiliation(s)
- Mihai Musteata
- Clinics Department, Faculty of Veterinary Medicine, University of Agricultural Science and Veterinary Medicine Iasi, Romania
| | - Alina Nicolescu
- Group of Biospectroscopy, Institute of Macromolecular Chemistry, Roumanian Academy, Iasi, Romania
- Group of Biospectroscopy, Centre of Organic Chemistry, Roumanian Academy, Bucharest, Romania
| | - Gheorghe Solcan
- Clinics Department, Faculty of Veterinary Medicine, University of Agricultural Science and Veterinary Medicine Iasi, Romania
| | - Calin Deleanu
- Group of Biospectroscopy, Institute of Macromolecular Chemistry, Roumanian Academy, Iasi, Romania
- Group of Biospectroscopy, Centre of Organic Chemistry, Roumanian Academy, Bucharest, Romania
- * E-mail:
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Liver. CANINE AND FELINE GASTROENTEROLOGY 2013. [PMCID: PMC7161409 DOI: 10.1016/b978-1-4160-3661-6.00061-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 02/18/2023]
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Gow AG, Marques AI, Yool DA, Crawford K, Warman SM, Eckersall PD, Jalan R, Mellanby RJ. Dogs with congenital porto-systemic shunting (cPSS) and hepatic encephalopathy have higher serum concentrations of C-reactive protein than asymptomatic dogs with cPSS. Metab Brain Dis 2012; 27:227-9. [PMID: 22354751 DOI: 10.1007/s11011-012-9278-x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/30/2011] [Accepted: 01/25/2012] [Indexed: 01/26/2023]
Abstract
Hepatic encephalopathy (HE) is a cause of significant morbidity and mortality in patients with liver disorders and a wide range of rodent models of HE have been described to facilitate studies into the pathogenesis and treatment of HE. However, it is widely acknowledged that no individual model perfectly mimics human HE and there is a particular need for spontaneous, larger animal models. One common congenital abnormality in dogs is the portosystemic shunt (cPSS) which causes clinical signs that are similar to human HE such as ataxia, disorientation, lethargy and occasionally coma. As inflammation has recently been shown to be associated with HE in humans, we hypothesised that inflammation would similarly be associated with HE in dogs with cPSS. To examine this hypothesis we measured C-reactive protein (CRP) in 30 healthy dogs, 19 dogs with a cPSS and no HE and 27 dogs with a cPSS and overt HE. There was a significant difference in CRP concentration between healthy dogs and dogs with HE (p < 0.001) and between dogs with HE and without HE (p < 0.05). The novel finding that there is an association between inflammation and canine HE strengthens the concept that HE in dogs with cPSS shares a similar pathogenesis to humans with HE. Consequently, dogs with a cPSS may be a good spontaneous model of human HE in which to further examine the role of inflammation and development of HE.
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Affiliation(s)
- A G Gow
- Royal (Dick) School of Veterinary Studies and The Roslin Institute, Division of Veterinary Clinical Studies, The University of Edinburgh, Hospital for Small Animals, Easter Bush Veterinary Centre, Midlothian, UK
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Gommeren K, Claeys S, De Rooster H, Hamaide A, Daminet S. Outcome from status epilepticus after portosystemic shunt attenuation in 3 dogs treated with propofol and phenobarbital. J Vet Emerg Crit Care (San Antonio) 2010; 20:346-51. [DOI: 10.1111/j.1476-4431.2010.00537.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Abstract
This chapter discusses the anatomy, functions, and biochemistry of cerebrospinal fluid (CSF). CSF has four major functions: physical support of neural structures, excretion and “sink” action, intracerebral transport, and control of the chemical environment of the central nervous system. CSF provides a “water jacket” of physical support and buoyancy. The CSF is protective because its volume changes reciprocally with changes in the volume of intracranial contents, particularly blood. Thus, the CSF protects the brain from changes in arterial and central venous pressure associated with posture, respiration, and exertion. Acute or chronic pathological changes in intracranial contents can be accommodated, to a point, by changes in the CSF volume. The direct transfer of brain metabolites into the CSF provides excretory function. This capacity is important because the brain lacks a lymphatic system. The lymphatic function of the CSF is also manifested in the removal of large proteins and cells, such as bacteria or blood cells, by bulk CSF absorption. The “sink” action of the CSF arises from the restricted access of water-soluble substances to the CSF and the low concentration of these solutes in the CSF.
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Stone TW, Forrest CM, Mackay GM, Stoy N, Darlington LG. Tryptophan, adenosine, neurodegeneration and neuroprotection. Metab Brain Dis 2007; 22:337-52. [PMID: 17712616 DOI: 10.1007/s11011-007-9064-3] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
This review summarises the potential contributions of two groups of compounds to cerebral dysfunction and damage in metabolic disease. The kynurenines are oxidised metabolites of tryptophan, the kynurenine pathway being the major route for tryptophan catabolism in most tissues. The pathway includes quinolinic acid -- an agonist at N-methyl-D-aspartate (NMDA) receptors, kynurenic acid -- an antagonist at glutamate and nicotinic receptors, and other redox active compounds that are able to generate free radicals under many physiological and pathological conditions. The pathway is activated in immune-competent cells, including glia in the central nervous system, and may contribute substantially to delayed neuronal damage following an infarct or metabolic insult. Adenosine is an ubiquitous purine that can protect neurons by suppressing excitatory neurotransmitter release, reducing calcium fluxes and inhibiting NMDA receptors. The extent of brain injury is critically dependent on the balance between the two opposing forces of kynurenines and purines.
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Affiliation(s)
- T W Stone
- Institute of Biomedical & Life Sciences, West Medical Building, University of Glasgow, Glasgow, Scotland, UK.
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Neumann S, Welling H, Thuere S. Evaluation of Serum L-phenylalanine Concentration as Indicator of Liver Disease in Dogs: A Pilot Study. J Am Anim Hosp Assoc 2007; 43:193-200. [PMID: 17615399 DOI: 10.5326/0430193] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Because essential amino acids are metabolized in the liver, liver diseases may impair their catabolism. In this study, serum L-phenylalanine concentrations in 28 dogs with liver diseases were compared with those of 28 healthy dogs and 13 dogs with nonhepatic diseases. Dogs with liver diseases had significantly increased L-phenylalanine serum concentrations compared to healthy dogs (P<0.001) and to those with nonhepatic diseases (P<0.01). There were no significant differences among the L-phenylalanine serum concentrations of dogs with different degrees of liver diseases. The sensitivity and specificity of L-phenylalanine to fasting bile acids were comparable.
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Affiliation(s)
- Stephan Neumann
- Small Animal Clinic, Institute of Veterinary Medicine, University of Goettingen, Goettingen, Germany
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