Dorrego A, Camino E, Gago P, Buendia-Andres A, Acurio K, Gonzalez S, de Juan L, Cruz-Lopez F.Equine piroplasmosis (EP) is caused by Theileria equi and Babesia caballi, transmitted by tick vectors. Horses can suffer an acute, subacute, and chronic forms of the disease, with clinical signs such as poor performance, fever, pale mucosal membranes, and jaundice. The diagnosis of EP subclinical cases is complex due to the sensitivity of real-time PCR and the limited parasite load in some carriers, making it challenging to differentiate them from seropositive, PCR negative (S+PCR-) individuals. This study aimed to describe haematological and biochemical changes in asymptomatic EP carriers, E...
van der Merwe D, van den Wollenberg L, van Hees-Valkenborg J, de Haan T, van der Drift S.We determined reference intervals (RIs) for concentrations of trace minerals and toxic elements based on liver samples from 122 apparently healthy horses at 2 slaughter facilities in the Netherlands. Samples were collected during the spring and fall of 2021, and the sex and age of the horses were registered upon sampling. Concentrations of arsenic, cadmium, chromium, cobalt, copper, iron, lead, manganese, molybdenum, nickel, selenium, vanadium, and zinc were measured in liver samples using inductively coupled plasma-mass spectrometry (ICP-MS) after nitric acid digestion. RIs were calculated us...
Ferlini Agne G, Somogyi AA, Sykes B, Knych H, Franklin S.In humans, omeprazole is metabolised by cytochrome P450 (CYP450) CYP2C19 and CYP3A4 with differences in CYP2C19 genotypes leading to variable response to therapy. Despite a wide use of omeprazole in horses with evidence of variable therapeutic efficiency, information regarding enzymatic metabolism is not currently available. This study aims to describe the in vitro kinetics of omeprazole metabolism and determine which enzyme(s) are responsible for omeprazole metabolism in horses. Omeprazole (0-800 uM) was incubated with liver microsomes and a panel of equine recombinant CYP450s (eq-rCYP). Meta...
Linn-Peirano SC, Hepworth-Warren K, Kinsella H, Diaz-Campos D, Brenseke BM, Cianciolo RE, Schroeder E, Schreeg ME.Equine ingesta-associated choledocholithiasis is a rare cause of morbidity and mortality. We describe here the clinical, gross, histologic, and microbiologic features of this condition in 2 horses and compare the features to 2 previous cases. Case 1 was a 4-y-old Thoroughbred mare with colic. Case 2 was an 18-y-old American Paint Horse mare with colic, chronic weight loss, and inappropriate mentation. Both had elevated biochemical markers of hepatocellular injury and cholestasis and were euthanized given a poor prognosis. Case 1 had a well-formed 5-cm choledocholith surrounding a piece of hay,...
Abalaka SE, Audu Z, Kolawole VO, Adeyemo BT, Idoko IS, Okafor ROS, Oyelowo-Abdulraheem FO, Tags SZ, Ogbe AO, Sanni S, Jegede OC, Sani NA, Tenuche OZ....Schistosomiasis is a worldwide snail-borne parasitic infestation of man and animals with acute or chronic phases having devastating sequelae. The present case report focused on post-mortem examination of a cachexic Dongola stallion ( Linnaeus, 1758) in Abuja, Nigeria, that failed to respond to treatment. Typical dense collagenous granulomatous lesions with marked inflammatory responses and fibrosis occurred in the liver and several visceral organs of the horse along with other lesions indicative of systemic collapse. Special Ziehl-Neelsen and Periodic Acid-Schiff staining as well as microbial ...
Satuu00e9 K, Fazio E, Medica P, Miguel L, Gardu00f3n JC.In the present review, the authors, based on the multiple functions performed by the liver, analyze the multiple biochemical and hematological changes as an expression of altered liver function in the horse. The liver performs important metabolic functions related to the synthesis, degradation, and excretion of various substances. Modification of these functions can be evaluated and diagnosed by determining serum concentrations of several serum analytes, including enzymes and other endogenous substances. Hepatocellular enzymes, such as sorbitol dehydrogenase-SDH and glutamate dehydrogenase-GLD...
Bourebaba L, Serwotka-Suszczak A, Pielok A, Sikora M, Mularczyk M, Marycz K.Equine metabolic syndrome (EMS) is a multifactorial pathology gathering insulin resistance, low-grade inflammation and past or chronic laminitis. Among the several molecular mechanisms underlying EMS pathogenesis, increased negative insulin signalling regulation mediated by protein tyrosine phosphatase 1 B (PTP1B) has emerged as a critical axis in the development of liver insulin resistance and general metabolic distress associated to increased ER stress, inflammation and disrupted autophagy. Thus, the use of PTP1B selective inhibitors such as MSI-1436 might be considered as a golden therapeut...
Karatt TK, Sathiq MA, Laya S, Philip M, Karakka Kal AK, Subhahar MB.An effective alternative to testosterone therapy is selective androgen receptor modulators, a class of compounds that has a tissue-specific effect on muscle and bone. These drugs, which enhance performance, pose a severe abuse risk in competitive sports. GLPG0492 is one of the selective androgen receptor modulators discovered in recent decades. This compound has a unique tissue-specific action for muscle and bone against steroid receptors and acts as a partial agonist for androgen receptors. This study examined GLPG0492 and its metabolites in vitro using equine liver microsomes. Liquid chromat...
Sazmand A, Yavari M, Babaei M, Nourian A, Otranto D.Migration of Ascaris lumbricoides through the papilla of Vater in humans, and entry into the biliary tree, is well-recognised. Ascaris suum and Toxocara vitulorum have been recovered from the liver of swine and buffalo. We necropsied a Persian Kurdish filly at age 6 months, weighing ∼100 kg. Death evidently was caused by oleander (Nerium oleander) intoxication. An 8-cm adult male Parascaris was found at the lobar-left hepatic bile duct junction. We suggest that the nematode entered anteriorly into the hepatic tree, via the duodenum, major duodenal papilla, bile duct, left hepatic duct and f...
Marycz K, Bourebaba N, Serwotka-Suszczak A, Mularczyk M, Galuppo L, Bourebaba L.Equine metabolic syndrome (EMS) is recognized as one of the leading cause of health threatening in veterinary medicine worldwide. Recently, PTP1B inhibition has been proposed as an interesting strategy for liver insulin resistance reversion in both equines and humans, however as being a multifactorial disease, proper management of EMS horses further necessities additional interventional approaches aiming at repairing and restoring liver functions. In this study, we hypothesized that in vitro induction of Eq_ASCs hepatogenic differentiation will generate a specialized liver progenitor-like cell...
Harding C, Viljanto M, Habershon-Butcher J, Taylor P, Scarth J.YK-11 is a steroidal selective androgen receptor modulator, a compound class prohibited in both equine racing and human sports because of their potentially performance enhancing properties. YK-11 is easily accessible via internet-based supplement vendors making this compound a possible candidate for doping; however, its phases I and II metabolism has not yet been reported in the horse. The purpose of this study was to investigate the in vivo metabolites of YK-11 in urine and plasma following oral administration with three daily doses of 50 mg to two Thoroughbred horses. In vitro incubations ...
Wanstrath MA, Bauck AG, Smith AD, Freeman DE.To assess the safety and efficacy of a method for digitally enlarging the caudal aspect of the epiploic foramen (EF). Methods: Healthy horses and clinical cases of EF entrapment (EFE). Methods: Fourteen healthy horses and three clinical cases. Methods: Through a ventral midline celiotomy under general anesthesia, the EF was enlarged by digital separation of the caudal attachments of the caudate lobe of the liver from right dorsal colon, right kidney, gastropancreatic fold, and pancreas. Healthy horses were euthanized under anesthesia, and the enlarged EF was measured at necropsy. Results: The ...
Taylor SD, Kritchevsky JE, Huang P, Olave C, Waxman SJ, Miller MA.To report history, clinical examination findings, clinicopathologic findings, diagnostic test results, treatment, and outcome in horses with a novel idiopathic hepatitis syndrome. 13 client-owned horses. Medical records of horses that were presented with fever and increased blood liver enzyme activity over a 16-month period were reviewed (December 1, 2020, to April 1, 2022). Collected data included signalment, history, clinical and clinicopathologic findings, diagnostic test results, treatment, clinical progression, and short-term outcome. Affected horses were presented between December and Ap...
Hoffman M, Cheong SH, Stokol T.Liver analyte measurement is important in the evaluation of sick animals. Liver injury in horses is recognized by increased glutamate dehydrogenase (GLDH), sorbitol dehydrogenase (SDH), and aspartate aminotransferase (AST) activities, whereas biliary pathology is identified by increased alkaline phosphatase and γ-glutamyl transferase (GGT) activities or bilirubin concentrations. We have observed high GLDH, but not SDH, activities in neonatal foals admitted for conditions other than liver disease. Only one previous study have evaluated GLDH activity over time in healthy neonatal foals; however...
Philip M, Karakka Kal AK, Subhahar MB, Karatt TK, Mathew B, Perwad Z, Graiban FM, Caveney MR, Sayed R, Kadry AM.According to previous research, aminorex is the major metabolite of levamisole; however, in the screening of levamisole-positive racehorse urine and plasma samples, aminorex could only be detected in trace amounts or not at all. In forensic laboratories, hydroxy levamisole and its phase II conjugates make it easier to confirm levamisole misuse and to differentiate between the abuse of levamisole and aminorex. This study aimed to identify the major levamisole metabolites that can be detected along with the parent drug. Methods: The study describes levamisole and its metabolites in thoroughbred ...
Jager MC, Tomlinson JE, Henry CE, Fahey MJ, Van de Walle GR.Theiler's disease, a.k.a. equine serum hepatitis, is a devastating, highly fatal disease of horses. Equine parvovirus-hepatitis (EqPV-H) has been identified as the likely cause of this disease. While the incidence of Theiler's disease is low, the prevalence of EqPV-H DNA in horses is high, with up to 37% in some regions, suggesting that subclinical or persistent infection is common. To determine the prevalence and pathogenicity of EqPV-H infection at New York racetracks, DNA was extracted from archived formalin-fixed, paraffin-embedded liver tissues from racehorses submitted for necropsy to th...
Tedesco DEA, Guerrini A.Milk thistle, , is a medicinal plant grown for its bioactive compounds with well-documented antioxidant and hepatoprotective properties. Milk thistle has a well-established pharmacological reputation for treatments of human liver disease, but it is also used in animals. This review summarizes the experimental evidence of milk thistle's effects on animals when administered as silymarin extract (feed additive) or a feed ingredient, if administered as seed or expeller/cake with the seed residue still containing the bioactive components. The use as a feed additive or feed ingredient is motivated b...
Current drug metabolismAugust 27, 2022
Volume 23, Issue 10 850-865 doi: 10.2174/1389200223666220825093945
Ishii H, Shibuya M, Kusano K, Sone Y, Kamiya T, Wakuno A, Ito H, Miyata K, Sato F, Kuroda T, Yamada M, Leung GN.Vadadustat, a hypoxia-inducible factor prolyl hydroxylase (HIF-PHD) inhibitor, is a substance which carries a lifetime ban in both horse racing and equestrian competition. A comprehensive metabolic study of vadadustat in horses has not been previously reported. Objective: Metabolism and elimination profiles of vadadustat in equine plasma and urine were studied for the purpose of doping control. Methods: A nasoesophageal administration of vadadustat (3 g/day for 3 days) was conducted on three thoroughbred mares. Potential metabolites were comprehensively detected by differential analysis of ful...
Jorge-Smeding E, Warnken T, Grob AJ, Feige K, Pudert T, Leung YH, Go YY, Kenu00e9z u00c1.Insulin dysregulation (ID) is a determinant of equine metabolic syndrome. Among the sphingolipids, ceramides contribute to the development of ID; however, the cross talk between the liver and adipose tissue (AT) depots and the variation among AT depots in terms of ceramide metabolism are not well understood. We aimed to characterize the sphingolipidome of plasma, liver, and AT (nuchal, NUAT; subcutaneous, SCAT; omental, OMAT; retroperitoneal, RPAT) and their associations with insulin response to oral glucose testing (OGT) in normoinsulinemic and hyperinsulinemic horses. Plasma, liver, and AT s...
Intemann S, Reckels B, Schubert DC, Wolf P, Kamphues J, Visscher C.Evidence has already been provided that feed-borne mold spores and endotoxins can trigger chronic, non-infectious respiratory disease if inhaled. Furthermore, deficiencies in feed microbiology are suspected to trigger gastrointestinal and liver disorders in horses, but the connection needs further clarification. Most of the previous studies regarding horse feed hygiene focused on forage, whereas research regarding hygienic quality of concentrates is scarce. In the present study, results of reports on hygienic quality of compound feed and cereals for horses were evaluated secondarily. Results i...
Hamamoto-Hardman BD, Steffey EP, Seminoff K, McKemie DS, Kass P, Knych HK.Although morphine has demonstrated antinociceptive effects in horses, its administration has been associated with dose-dependent adverse effects. In humans and rats, part of the analgesic effect of morphine has been attributed to the active metabolite, morphine-6-glucuronide (M6G). Although morphine can cause several undesirable effects, M6G has a more favorable safety profile. The objective of this study was to characterize the pharmacokinetics, tissue distribution, and behavioral and select physiological effects of M6G following intravenous administration to a small group of horses. In Part ...
Durham AE.Outbreaks of liver disease in horses are common but the etiology of most remains unknown. Forage mycotoxins have been suspected to be a cause. Objective: To examine the association between outbreaks of liver disease and the presence of mycotoxins in forage stored on the same premises. Methods: Premises were identified where ≥4 horses were contemporaneously affected by liver disease, and a control group was formed from premises where ≥4 horses had been examined and found to have no evidence of liver disease. Methods: Forage was collected from 29 case and 12 control premises. The forage was ...
Ali HHM, Al-Bayati LH. is one of the most important pathogens, which causes a marked economic loss in small ruminants, in particular sheep, worldwide. This study aimed to detect the prevalence of in the sera of aborted ewes in Wasit province, Iraq, using the enzyme-linked immunosorbent assay (ELISA), followed by the investigation of the main histopathological alterations that occurred in some organs of the dead newborns. Out of 180 tested samples by ELISA, 32.22% of the evaluated animals showed positive reactions to IgG antibodies toward . Concerning the titers of the infection of seropositive ewes, there were sig...
Badenhorst M, Saalmu00fcller A, Daly JM, Ertl R, Stadler M, Puff C, de le Roi M, Baumgu00e4rtner W, Engelmann M, Brandner S, Junge HK, Pratscher B....Equine hepacivirus (EqHV) is the closest known genetic homologue of hepatitis C virus. An effective prophylactic vaccine is currently not available for either of these hepaciviruses. The equine as potential surrogate model for hepacivirus vaccine studies was investigated, while equine host responses following vaccination with EqHV E2 recombinant protein and subsequent EqHV inoculation were elucidated. Four ponies received prime and booster vaccinations (recombinant protein, adjuvant) four weeks apart (day -55 and -27). Two control ponies received adjuvant only. Ponies were inoculated with EqHV...
Mann S, Abuelo A, Stokol T, Wakshlag JJ, Bayly W, Reed S, Gandy J, Ramsay JD, Divers TJ.High serum γ-glutamyl-transferase (GGT) activity syndrome in racehorses has been associated with maladaption to exercise. Investigation of affected horses before and immediately after standard exercise may provide critical insight into the syndrome's pathophysiology. Objective: To investigate blood biomarker changes in actively competing racehorses with high GGT activity associated with an exercise challenge. Methods: Case-control study. Methods: High GGT case (age: 2-3 years) and normal GGT control (age: 2-7 years) pairs (3 Thoroughbred, 4 Standardbred pairs) at least 3 months into thei...
One health outlookMay 9, 2022
Volume 4, Issue 1 9 doi: 10.1186/s42522-022-00065-y
Gu00f6mer A, Puff C, Reinecke B, Bracht S, Conze M, Baumgu00e4rtner W, Steinmann J, Feige K, Cavalleri JMV, Steinmann E, Todt D.The Equine Hepacivirus (EqHV) is an equine-specific and liver-tropic virus belonging to the diverse genus of Hepaciviruses. It was recently found in a large donkey (Equus asinus) cohort with a similar seroprevalence (30%), but lower rate of RNA-positive animals (0.3%) compared to horses. These rare infection events indicate either a lack of adaptation to the new host or a predominantly acute course of infection. Methods: In order to analyze the susceptibility and the course of EqHV infection in donkeys, we inoculated two adult female donkeys and one control horse intravenously with purified Eq...
Romano MC, Francis KA, Janes JG, Poppenga RH, Filigenzi MS, Stefanovski D, Gaskill CL.Poisoning of nontarget species is a major concern with the use of anticoagulant rodenticides (ARs). At postmortem examination, differentiating toxicosis from incidental exposure is sometimes difficult. Clotting profiles cannot be performed on postmortem samples, and clinically significant serum, blood, and liver AR concentrations are not well-established in most species. We chose diphacinone for our study because, at the time, it was the publicly available AR most commonly detected in samples analyzed at the University of Kentucky Veterinary Diagnostic Laboratory. We determined an approximate ...
Satuu00e9 K, Miguel-Pastor L, Chicharro D, Gardu00f3n JC.For diagnostic purposes, liver enzymes are usually classified into hepatocellular and cholestatic. These two groups of equine liver-specific enzymes include sorbitol dehydrogenase (SDH), glutamate dehydrogenase (GLDH), γ-glutamyl transferase (GGT), aspartate aminotransferase (AST), lactate dehydrogenase (LDH), and alkaline phosphatase (ALP). SDH and GLDH mostly reflect hepatocellular injury and cholestasis, while GGT expresses high values in biliary necrosis or hyperplasia. Likewise, AST, LDH, and ALP also reflect hepatocellular and biliary disease, but these enzymes are not liver specific. F...
Yocom AF, O'Fallon ES, Gustafson DL, Contino EK.Cannabidiol (CBD) products are widely marketed to horse owners, trainers, and veterinarians and are readily available to the consumer despite minimal pharmacokinetic or safety data being available. The objectives of this study were to determine the plasma pharmacokinetics, short-term safety, and synovial fluid levels of CBD following oral administration in horses. A prospective, randomized, controlled study design was used. Twelve horses were administered sunflower lecithin oil-based CBD at either 1 mg/kg (Group 1) or 3 mg/kg (Group 2) for a 24-hour pharmacokinetic study. Horses then received ...
Barrell EA.Polyuria and polydipsia are rare, but significant, manifestations of several different diseases of horses. Causes can be endocrine, iatrogenic, psychogenic, infectious, or toxic in nature and can also be due to primary renal disease or diseases of other organs, such as the liver. Although numerous causes of polyuria and polydipsia in horses exist, the most common conditions include chronic kidney disease, pituitary pars intermedia dysfunction, and psychogenic polydipsia with secondary polyuria. Additional testing is dictated by history, other clinical signs, and the results of blood work and/o...
Zink MC, Yager JA, Smart NL.Of 131 cases of Corynebacterium equi infection in horses submitted for necropsy to the Ontario Veterinary College or Veterinary Laboratory Services, OMAF, Guelph, Ontario from 1958 to 1984, 115 were diagnosed as suppurative pneumonia, and of these 55 had associated ulcerative enterocolitis. Only five animals had intestinal involvement without pulmonary lesions. The remaining 11 cases included arthritis/cellulitis, skin abscesses and submandibular lymphadenitis. While the lung, intestine and associated lymph nodes yielded C. equi most frequently, in 21% of cases C. equi was also cultured from p...
Valberg SJ, Ward TL, Rush B, Kinde H, Hiraragi H, Nahey D, Fyfe J, Mickelson JR.Seven related Quarter Horse foals that died by 7 weeks of age were examined for glycogen branching enzyme (GBE) deficiency. Clinical signs varied from stillbirth, transient flexural limb deformities, seizures, and respiratory or cardiac failure to persistent recumbency. Leukopenia (5 of 5 foals) as well as high serum creatine kinase (CK; 5 of 5), aspartate transaminase (AST; 4 of 4), and gamma glutamyl transferase (GGT; 5 of 5) activities were present in most foals, and intermittent hypoglycemia was present in 2 foals. Gross postmortem lesions were minor, except for pulmonary edema in 2 foals....
Caloni F, Cortinovis C.Fumonisins, trichothecenes and zearalenone are the most commonly occurring Fusarium mycotoxins in cereal grains and animal feed. In this review, the toxicity of these mycotoxins in horses is considered with particular reference to recent data on specific and proposed syndromes. Compared to other animal species, very little information is available on the adverse effects of fusariotoxins in horses. Fumonisin B(1) (FB(1)) is the causative agent of leukoencephalomalacia, which is typified by depression, aimless circling, head pressing, paresis, ataxia, blindness and death. FB(1) has also been sho...
Tegtmeyer B, Echelmeyer J, Pfankuche VM, Puff C, Todt D, Fischer N, Durham A, Feige K, Baumgu00e4rtner W, Steinmann E, Cavalleri JV.Equine hepacivirus (EqHV) in equids represents the closest homologue to hepatitis C virus (HCV) infecting humans. A majority of HCV infected patients develop a chronic course of infection leading to liver fibrosis, cirrhosis and liver failure. However, in horses mostly transient mild subclinical infections are reported for EqHV to date. EqHV can be involved in chronic liver diseases of horses. Biochemical parameters in serum samples were measured. Viral load was determined using qPCR. Next generation sequencing (NGS) of serum was performed. Liver tissue was stained with haematoxylin and eosin ...
Crichton RR, Millar JA, Cumming RL, Bryce CF.1. Ferritin was isolated from human and horse spleen and liver, and apoferritin prepared therefrom. 2. The electrophoretic mobilities of the four apoferritins were determined on polyacrylamide gels and on cellulose acetate strips, and all found to be equal. 3. Homologous ferritins share reactions of identity in immunodiffusion experiments, whereas heterologous ferritins show only partial identity. 4. The subunit molecular weight of each of the apoferritins was determined by polyacrylamide-gel electrophoresis in sodium dodecyl sulphate and by chromatography on agarose columns in 6m-guanidine-HC...
Nebbia C, Ceppa L, Dacasto M, Nachtmann C, Carletti M.The oxidative metabolism of monensin, an ionophore antibiotic extensively used in veterinary practice as a coccidiostat and a growth promoter, was studied in hepatic microsomal preparations from horses, pigs, broiler chicks, cattle and rats. As assayed by the measurement of the amount of the released formaldehyde, the rate of monensin O-demethylation was nearly of the same order of magnitude in all species, but total monensin metabolism, which was estimated by measuring the rate of substrate disappearance by a high-performance liquid chromatography (HPLC) method, was highest in cattle, interme...
Guglick MA, MacAllister CG, Ely RW, Edwards WC.Seven horses developed clinical or subclinical hepatitis 48 to 87 days after administration of tetanus antitoxin. One horse had mildly high hepatic enzyme activity 120 days after inoculation with tetanus antitoxin. The first horse developed signs of depression, lethargy, and anorexia. During hospitalization, signs of hepatoencephalopathy were noticed, and laboratory data were consistent with hepatic disease. Another horse that was found dead had gross and histologic lesions compatible with serum hepatitis. Screening of serum gamma-glutamyltransferase (GGT) and aspartate transaminase activities...
Marycz K, Szu0142apka-Kosarzewska J, Geburek F, Kornicka-Garbowska K.Equine metabolic syndrome (EMS) is characterized by adiposity, insulin dysregulation and increased risk for laminitis. Increased levels of specific liver enzymes in the peripheral blood are typical findings in horses diagnosed with EMS. Current management of EMS is based on caloric restriction and increased physical activity. However, new potential treatment options are arising such as the transplantation of autologous adipose stem cells (ASC). However, cytophysiological properties of ASC derived from EMS horses are impaired which strongly limits their therapeutic potential. We hypothesized, t...
Oliveira-Filho JP, Badial PR, Cunha PH, Peiru00f3 JR, Arau00fajo JP, Divers TJ, Winand NJ, Borges AS.Hepcidin has been found to be the key regulator of iron metabolism that leads to hypoferremia during inflammation. Recent work has shown that equine hepcidin is predominantly expressed in the liver of horses. In this study, hepcidin gene expression was determined in the liver and bone marrow of six healthy horses after iv infusion of Escherichia coli O55:B5 LPS. The IL-6 gene expression was also determined in liver and bone marrow samples. Clinical and laboratory evaluations were measured at multiple time points between 0 and 240 h post-LPS infusion (PI). Liver and bone marrow biopsies were ...
Zhao K, Chi Y, Shen X.As a consequence of contracted and fenced grassland, the incidence of edema pathema in the Hequ horse is rising. The main pathological symptoms are edema, emaciation, anemia, heterophilia, inappetence, and dyskinesia. To study the cause of edema disease in Hequ horse, the Hequ horse farm with a high incidence was chosen as the experimental pasture, and the Azi husbandry experimental station without edema disorder was the control pasture. The research methods in this paper are included: (1) The mineral contents in soil, forage, blood, and liver were analyzed. (2) Routine parameters and biochemi...
Gather T, Walter S, Pfaender S, Todt D, Feige K, Steinmann E, Cavalleri JM.The recently discovered nonprimate hepacivirus (NPHV) naturally infects horses and is the closest known homolog of hepatitis C virus to date. Within a follow-up study acute field infections were monitored in four young Thoroughbred horses until the ages of 12-13 months. Serum samples were analyzed for the presence of NPHV RNA and anti-NPHV NS3 antibodies and liver specific parameters were evaluated. The four young horses were not able to clear infection, but remained chronically infected for the entire monitored time period despite the presence of NPHV specific antibodies.
DeNotta SL, Divers TJ.The gastrointestinal tract and liver comprise key components of the equine digestive system and together have important functions in metabolism, digestion, absorption, detoxification, and synthesis. Disorders of the gastrointestinal tract and liver are common in clinical practice and can cause a variety of clinical signs. Hematologic and biochemical analysis can be helpful for identifying organ dysfunction, narrowing down the differential diagnostic list, and monitoring progress and response to treatment. This article details hematologic and biochemical tests that are important in the evaluati...
Mu00f6ssner LD, Schmitz A, Theurillat R, Thormann W, Mevissen M.To identify and characterize cytochrome P450 enzymes (CYPs) responsible for the metabolism of racemic ketamine in 3 mammalian species in vitro by use of chemical inhibitors and antibodies. Methods: Human, canine, and equine liver microsomes and human single CYP3A4 and CYP2C9 and their canine orthologs. Methods: Chemical inhibitors selective for human CYP enzymes and anti-CYP antibodies were incubated with racemic ketamine and liver microsomes or specific CYPs. Ketamine N-demethylation to norketamine was determined via enantioselective capillary electrophoresis. Results: The general CYP inhibit...
Nyaoke AC, Navarro MA, Beingesser J, Uzal FA.A 14-y-old bay Quarter Horse gelding was presented with progressive neurologic signs, elevated rectal temperature, and icterus for 3 d prior to death. Postmortem examination revealed icterus, large amounts of serosanguineous fluid in the abdominal cavity, widespread petechiae and ecchymoses in several organs, and a large, pale, and well-demarcated focus of necrosis in the liver. Histologically, there was coagulative necrosis surrounded by a rim of inflammatory cells and large numbers of gram-positive rods, which were identified as Clostridium novyi by immunohistochemistry. Liver samples tested...
Nebbia C, Dacasto M, Rossetto Giaccherino A, Giuliano Albo A, Carletti M.The apoprotein expression and the catalytic activities of cytochrome P450s involved in the biotransformation of xenobiotics were investigated in horse liver microsomes and compared with those of food producing (cattle, pigs, broiler chicks, and rabbits) and laboratory species (rats). Western blot analysis revealed the presence of proteins immunorelated to rat CYP 1A, CYP 2B, CYP 2E, and CYP 3A subfamilies in hepatic microsomes from horses and from any other examined species. With the exception of the N-demethylation of N-nitrosodimethylamine in broiler chicks, all the recorded interspecies dif...
Plapp BV, Savarimuthu BR, Ferraro DJ, Rubach JK, Brown EN, Ramaswamy S.During catalysis by liver alcohol dehydrogenase (ADH), a water bound to the catalytic zinc is replaced by the oxygen of the substrates. The mechanism might involve a pentacoordinated zinc or a double-displacement reaction with participation by a nearby glutamate residue, as suggested by studies of human ADH3, yeast ADH1, and some other tetrameric ADHs. Zinc coordination and participation of water in the enzyme mechanism were investigated by X-ray crystallography. The apoenzyme and its complex with adenosine 5'-diphosphoribose have an open protein conformation with the catalytic zinc in one pos...
McCraw BM, Slocombe JO.Pony foals inoculated with infective Strongylus edentatus larvae were monitored for clinical signs and selected blood changes and were examined at necropsy from two to 56 days postinfection. Larvae penetrated the intestine and reached the liver intravenously before 40 hours postinfection. Occasional thrombi and larval tracks associated with the intima of cecal and colic veins suggested aberrant paths. Larvae in the liver doubled in width between seven and 15 days postinfection and a sudden increment in circulating eosinophils occurred between 11 and 15 days. These changes were probably associa...
Suagee JK, Corl BA, Crisman MV, Wearn JG, McCutcheon LJ, Geor RJ.The lipogenic capacities of equine liver and adipose tissue explants were investigated in vitro. Preference for glucose or acetate as the primary carbon source for de novo fatty acid synthesis was determined using (14)C labeled substrates. Additional aims included determining the relative contribution of NADPH generating pathways to reducing equivalent generation and comparing the lipogenic activity of two adipose depots, mesenteric and subcutaneous harvested from the crest region of the neck. Mesenteric adipose tissue had greater lipogenic activity than subcutaneous adipose tissue, and liver ...
Li G, Lee P, Mori N, Yamamoto I, Arai T.Continuous high intensity training may induce alterations to enzyme activities related to glucose and lipid metabolism in horses. In our study, five Thoroughbred race horses (3 male and 2 female, avg age=5 yrs old) were compared against five riding horses (1 male, 1 female, 3 gelding, avg age=13 yrs old) in terms of energy metabolism, by examining plasma malate (MDH) and lactate (LDH) dehydrogenase activities and M/L ratio. MDH is involved in NADH and ATP generation, whereas LDH can convert NADH back into NAD(+) for ATP generation. An increase in plasma M/L ratio can reflect heightened energy ...
Maly IP, Sasse D.Microquantitative measurements of ADH-activity were carried out on the livers of male and female rats, guinea-pigs and horses (two geldings and a mare). Lyophilized cryostat sections of liver parenchyma were microdissected the whole way along the sinusoidal length from the terminal afferent vessels to the terminal efferent venule. ADH activity in samples of about 50-150 ng was measured in a microbiochemical assay using the oil-well technique without enzymatic cycling, by direct luminometric determination of NADH. On the basis of the single measurements, mean values of total hepatic ADH activit...
Heller MC, Drew CP, Jackson KA, Griffey S, Watson JL.Rhodococcus equi is a facultative intracellular bacterial pathogen of foals and immunocompromised humans that infects and proliferates within host macrophages and dendritic cells (DC). Indoleamine 2,3-dioxygenase (IDO), the initial enzyme in the tryptophan catabolism pathway, is upregulated in R. equi infected equine monocyte-derived DC and alveolar macrophages. Tryptophan requirement of R. equi for extracellular and intracellular growth was assessed. Growth of R. equi in minimal media did not require tryptophan and pharmacologic inhibition of IDO had no effect on intracellular proliferation o...
Mann S, Ramsay JD, Wakshlag JJ, Stokol T, Reed S, Divers TJ.High-serum γ-Glutamyl Transferase (GGT) activity has been associated with and thought to be a marker of maladaptation to training and possibly poor performance in racehorses, but the cause is unknown. Objective: To investigate possible metabolic and infectious causes for the high GGT syndrome. Methods: Pilot case-control study and nested case-control study. Methods: The case-control study in 2017 included 16 horses (8 cases and 8 controls with median [range] serum GGT 82 [74-148] and 22 [19-28] IU/L, respectively) from the same stable. In 2018, similar testing was performed in a nested case-...
Tomlinson JE, Van de Walle GR, Divers TJ.Theiler disease (serum hepatitis or idiopathic acute hepatic necrosis) has long been suspected to have a viral etiology. Four viruses have been described in association with hepatitis in horses. Further investigation suggests equine pegivirus and Theiler disease-associated virus (a second pegivirus) are neither hepatotropic nor pathogenic. Nonprimate hepacivirus (NPHV) causes subclinical disease in experimental models and has been associated with hepatitis in some clinical cases. Equine parvovirus-hepatitis (EqPV-H) experimentally causes subclinical-to-clinical liver disease and is found in th...
Messer NT, Johnson PJ.Acute hepatic disease was diagnosed in 16 horses during the study period. Twelve of those cases were characterized as idiopathic acute hepatic disease (IAHD). In 9 of the 12 (75%) cases of IAHD, the horses were female, and 7 of the 9 females were lactating and had been treated with tetanus antitoxin at parturition. Diagnosis of IAHD was based on anamnesis, clinical signs, and results of serum biochemical analyses, hepatic biopsy, and postmortem examination. Within 1 year of the illness, 75% (9/12) of the horses had died or had been euthanatized. Not all horses had the typical fulminant signs a...
Step DL, Blue JT, Dill SG.Acute, severe hemolytic anemia occurred in a horse being treated for tetanus with intravenous penicillin and tetanus antitoxin. During treatment, the horse developed a positive direct antiglobulin test and a high titer (maximum 1:1024) of IgG anti-penicillin antibody. The horse recovered from the tetanus and penicillin induced hemolytic anemia, but later developed acute hepatic failure, probably resulting from the administration of equine origin tetanus antitoxin.
Tadros EM, Frank N, Donnell RL.To test the hypothesis that inflammatory responses to endotoxemia differ between healthy horses and horses with equine metabolic syndrome (EMS). Animals-6 healthy horses and 6 horses with EMS. Methods: Each horse randomly received an IV infusion of lipopolysaccharide (20 ng/kg [in 60 mL of sterile saline {0.9% NaCl} solution]) or saline solution, followed by the other treatment after a 7-day washout period. Baseline data were obtained 30 minutes before each infusion. After infusion, a physical examination was performed hourly for 9 hours and at 15 and 21 hours; a whole blood sample was collect...
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