ORCID Profile
0000-0002-2820-8431
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University of Queensland - Gatton Campus
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Publisher: Wiley
Date: 15-10-2015
DOI: 10.1111/JVIM.12478
Publisher: Wiley
Date: 26-02-2020
DOI: 10.1111/JVIM.15747
Publisher: American Society of Hematology
Date: 11-02-2016
DOI: 10.1182/BLOOD-2015-02-628867
Abstract: Gas6 promotes cancer-induced thrombosis by regulating the expression of Ptges from the endothelium. Gas6-dependent PGE2 secretion from the endothelium leads to platelet activation and venous thrombosis.
Publisher: Wiley
Date: 16-10-2019
DOI: 10.1111/JVIM.15629
Publisher: Wiley
Date: 11-03-2011
DOI: 10.1111/J.2042-3306.2010.00313.X
Abstract: Studies investigating the clinical efficacy of albuterol administered with the same propellant and commercially available delivery devices in horses with recurrent airway obstruction (RAO) are not currently available. To determine the efficacy of aerosolised albuterol administered to horses with RAO by means of 2 commercially available, hand-held delivery devices. Ten horses with RAO were kept in a dusty environment and fed mouldy hay to induce airway obstruction. Lung mechanics were measured before and after the procedure. ΔP(max) was measured 5 min after administration of 180 µg of albuterol from a pressurised metered dose inhaler, using an aerosol delivery device chosen randomly. This process was repeated every 5 min until maximal bronchodilation was achieved. After a 24 h washout period, lung mechanics data were again collected using the other aerosol delivery device. Aerosolised albuterol induced a significant and rapid bronchodilation in the horses using both aerosol delivery devices. No statistically significant difference in pulmonary function was observed in response to albuterol therapy between the 2 devices. The dose required to achieve 50% of maximal bronchodilation was not statistically different between the 2 devices (173.35 ± 78.35 µg with Device 1 and 228.49 ± 144.99 µg with Device 2, P = 0.26). The decrease in lung resistance tended to be more pronounced after albuterol administration with Device 1 (P = 0.066). Aerosolised albuterol is an effective bronchodilator in horses with recurrent airway obstruction. There is no statistically significant difference between the 2 commercially available aerosol delivery devices in terms of efficacy. Aerosolised albuterol is effectively delivered using currently available devices leading to maximal bronchodilation in horses with RAO at an average dose of 540 µg.
Publisher: Wiley
Date: 09-2019
DOI: 10.1111/JVIM.15620
Abstract: Plasma adrenocorticotropic hormone (ACTH) and serum cortisol concentrations increase with illness‐associated stress. Dynamics of plasma ACTH and serum cortisol concentrations in adult horses with systemic illness are undocumented. To determine whether ACTH and cortisol concentrations and the ACTH/cortisol ratio vary with survival, the presence of systemic inflammatory response syndrome (SIRS), or ischemic gastrointestinal lesions at admission, or throughout hospitalization. One hundred fifty‐one adult horses. Prospective study measuring serum cortisol and plasma ACTH at admission and on days 2, 4, and 6 of hospitalization. Horses were grouped by outcome (survival, SIRS status, number of SIRS criteria [SIRS score], SIRS severity group, and the presence of an ischemic lesion). Differences between groups and over time for ACTH, cortisol, and ACTH/cortisol ratio were investigated with a mixed effect model. Receiving operator characteristic curves and odds ratios were calculated for survival and ischemia. In all groups, ACTH, cortisol, and ACTH/cortisol ratio significantly decreased over time ( P .0001). ACTH, cortisol, and ACTH/cortisol ratio were higher at admission in nonsurvivors, and ACTH and cortisol were higher in horses with ischemic lesions ( P .01). Horses with ACTH above reference interval at admission were 6.10 (2.73‐13.68 [95% confidence interval]) times less likely to survive ( P .0001). No significant difference in ACTH, cortisol, and ACTH/cortisol ratio between horses with different SIRS status, scores, or groups were detected, although nonsurvivors had a higher SIRS score ( P .0001). Pituitary and adrenal responses are altered in nonsurviving horses and those with an ischemic gastrointestinal lesion.
Publisher: Wiley
Date: 24-12-2021
DOI: 10.1111/JVIM.16017
Abstract: Diagnosis of pituitary pars intermedia dysfunction (PPID) is problematic because of large variations in ACTH concentrations. Compare the test characteristics of baseline and post–thyrotropin‐releasing hormone (TRH) stimulation plasma ACTH concentrations in horses using diagnostic cutoff values (DCOVs) and reference intervals (RIs) and determine the clinical consequences of using each method. One hundred six mature horses: 72 control cases and 34 PPID cases. Prospective case‐controlled study. Horses underwent monthly TRH stimulation tests. Diagnostic cutoff values were determined monthly by receiver operating characteristic curves using the Youden index. Reference intervals were determined monthly by a robust method. For each case age, sex and body condition score (BCS) were recorded. Baseline ACTH concentrations varied by month ( P .001) with significant “month × age” ( P = .003), “month × sex” ( P = .003), and “month × BCS” ( P = .007) effects. Baseline ACTH concentrations were accurate to diagnose PPID (0.91 ± 0.06) with DCOVs increasing the test sensitivity (0.61 ± 0.21 to 0.87 ± 0.05, P = .002) and RI increasing test specificity (0.85 ± 0.12 to 0.98 ± 0.01, P = .01). Thyrotropin‐releasing hormone stimulation improved test accuracy (0.91 ± 0.06 to 0.97 ± 0.03, P = .004). ACTH concentrations follow a circannual rhythm and vary with physiological factors. As using DCOVs increases the ability to detect mild cases and using RI decreases the risk of unnecessary treatments, ACTH concentrations should be interpreted within a specific clinical context. The TRH stimulation test improves the diagnosis of PPID.
Publisher: MDPI AG
Date: 23-06-2023
DOI: 10.3390/ANI13132082
Abstract: Crofton weed (Ageratina adenophora) is a global and highly invasive weed, with ingestion causing severe respiratory disease in horses, leading to irreversible and untreatable pulmonary fibrosis and oedema. While reports of equine pneumotoxicity remain common in Australia and New Zealand, equine pneumotoxicity may be underdiagnosed in other countries where Crofton weed is endemic but poorly differentiated. The pathogenesis of Crofton weed toxicity following ingestion has been well described in a number of different animal models, including rodents, rabbits, and goats. However, induced toxicity is organ-selective across different animal species, and these vastly differ from the pathogenesis described in horses, both clinically and after experimental exposure. Sources of variation may include species-specific susceptibility to different toxins present in the plant, different mechanistic processes of toxicity, and species differences in toxin biotransformation and bioactivation across different organs. Considering disease severity and Crofton weed’s invasiveness globally, assessing published toxicological and exposure data is necessary to advance research, identify specific toxins for horses, and possible prophylactic and therapeutic strategies. This review presents an overview of the available literature on equine toxicity, parallels between toxicity in horses and other animal species, and important aspects to be included in the future research agenda.
Publisher: Wiley
Date: 24-05-2022
DOI: 10.1111/VSU.13823
Abstract: To assess the effect of vocal cordectomy on airflow across equine larynges at different Rakestraw grades of arytenoid abduction using a unidirectional airflow model. Ex vivo, repeated measures. Twenty cadaveric equine larynges. The right arytenoid cartilage was maximally abducted in all larynges. Each larynx was assigned a Rakestraw grade A or B, and the left arytenoid was abducted accordingly. Each larynx was tested under 3 conditions: intact, left vocal cordectomy (LVC), and bilateral vocal cordectomy (BVC). Translaryngeal pressure and airflow were measured, and digital video footage was obtained. Translaryngeal impedance (TLI) was calculated, and the arytenoid left‐to‐right quotient angle (LRQ) and rima glottis cross‐sectional area (CSA) were measured from standardized still images. Vocal cordectomy reduced TLI by 14.5% in LVC in comparison with intact larynges at Rakestraw grade B ( P = .014). In Rakestraw grade A position, neither unilateral nor bilateral vocal cordectomy had any effect on TLI. Regardless of Rakestraw allocation, both LVC and BVC increased CSA in comparison with intact larynges ( P .005), with BVC larynges experiencing a greater effect than LVC ( P .0001). Using a unilateral airflow model, LVC improved TLI in larynges where arytenoid position approximated Rakestraw grade B. However, when the arytenoid position approximated Rakestraw grade A, there was no effect on TLI following LVC or BVC. Surgeons considering a vocal cordectomy should take into account the degree of arytenoid abduction before performing the procedure, as it may not be warranted from a TLI point of view.
Publisher: Elsevier BV
Date: 02-2019
DOI: 10.1111/JTH.14339
Abstract: Essentials Neutrophil extracellular traps (NETs) are generated during deep vein thrombosis (DVT). The role of interferon γ (IFNγ) and natural killer (NK) cells in NET formation was studied. IFNγ promote venous thrombosis through NET formation. NK cell depletion reduces DVT. SUMMARY: Background Neutrophils contribute to venous thrombosis through the release of neutrophil extracellular traps (NETs), but the mechanism triggering their formation remains unclear. In vitro data show that interferon (IFN)-γ induces the formation of NETs. Objectives To determine whether IFN-γ and the transcription factor T-box expressed on T cells (Tbet) promote venous thrombosis through neutrophil activation. Methods Venous thrombosis was induced by flow restriction in the inferior vena cava in IFN-γ
Publisher: American Veterinary Medical Association (AVMA)
Date: 06-2019
Abstract: To investigate the effect of high doses of orally administered levothyroxine sodium (LT 4 ) on serum concentrations of triiodothyronine (T 3 ) and thyroxine (T 4 ) in euthyroid horses. 12 healthy adult horses. 10 horses initially received water (vehicle) or 240 mg (5X treatment) or 480 mg (10× treatment) of LT 4 , and blood s les were collected at baseline (0 hours) and 0.5, 1, 2, 4, 6, 8, 10, 12, 18, 24, 48, 72, 96, and 120 hours after treatment to measure serum T 3 and T 4 concentrations. Three horses then received 480 mg of LT 4 for 14 days, and T 4 concentration was measured on days 0, 14, 21, 28, and 35. Changes in T 3 and T 4 concentrations were compared over time and among treatments. One-time administration of LT 4 resulted in variable but significant increases in both T 3 and T 4 concentrations for up to 120 hours however, T 3 and T 4 concentrations rarely exceeded reference intervals with either treatment. Prolonged administration of 480 mg of LT 4 resulted in a 15-fold increase in T 4 concentration after 14 days, but concentration returned to day 0 values within 21 days after LT 4 administration was discontinued. In euthyroid horses, administration of a high dose of LT 4 resulted in mild increases in thyroid hormone concentrations however, prolonged administration of high doses of LT 4 resulted in markedly increased thyroid hormone concentrations that returned to pretreatment values within 3 weeks after discontinuation of LT 4 administration. These results indicated complex kinetics of LT 4 and suggested a possible saturation of T 4 excretion in euthyroid horses.
Publisher: American Veterinary Medical Association (AVMA)
Date: 04-2014
Abstract: Objective —To develop and assess the short-term feasibility, maintenance, and complications associated with percutaneous endoscopic gastrostomy (PEG) tube placement in standing horses. Animals —6 adult horses. Procedures —Feasibility of the technique was evaluated in 2 horses. In each of 4 other horses, a PEG tube was maintained for 14 days and used to provide fluid requirements during the latter 7 days, before removal. Following air inflation of the stomach, each PEG tube was placed via a left intercostal approach proper tube location was ascertained by percutaneous ultrasonography and gastroscopy. The horses underwent physical examinations, CBCs, and peritoneal fluid analyses before and at intervals after tube placement. Seven days after tube removal, horses were euthanized and necropsied. Results —Placement of a PEG tube was feasible in all 6 horses. The 4 horses assessed long term tolerated water administration through the PEG tube and remained clinically stable throughout the 21-day experiment. However, during the period PEG tubes were in place, significant increases in some peritoneal and hematologic variables were detected. Postmortem evaluation revealed localized peritonitis in 1 horse and body wall inflammation along the PEG tube tracks in 3 additional horses. Conclusions and Clinical Relevance —Placement and maintenance of a PEG tube were tolerated well by the study horses, although peritoneal and systemic inflammation were detectable. Fluid requirements were adequately met with this technique, which could provide an alternative method for managing chronically dysphagic horses. Nevertheless, further research is warranted to evaluate the feasibility of enteral feeding by use of this approach in horses.
Publisher: Elsevier BV
Date: 2013
DOI: 10.1016/J.DOMANIEND.2012.07.003
Abstract: Equine insulin resistance is important because of its association with laminitis. The insulin-response test is described to diagnose insulin resistance in clinical settings. Practitioners may be reluctant to perform this test because of the time needed for the test and the fear of inducing hypoglycemia. The objective of the study was to compare a 2-step insulin-response test with a complete insulin-response test. A complete insulin-response test was performed on 6 insulin-resistant horses and 6 controls. A 2-step insulin-response test consisting of an intravenous injection of 0.1 IU/kg human insulin and blood glucose determination at 0 and 30 min after injection was performed on the same horses. Times to reach a 50% reduction of glucose baseline were compared between tests and horses. All the horses tolerated both tests well. No significant difference was observed between baseline glucose concentrations of insulin-resistant horses and controls (P = 0.09). Time to reach 50% reduction of glucose baseline for controls was not significantly different with the use of the complete insulin-response test or the 2-step test (P = 0.98). For insulin-resistant horses, the time to reach 50% reduction of glucose baseline with the use of the 2-step test was significantly longer than for controls (P = 0.004). With a cut-off time of 30 min, the 2-step test had the same characteristics as the complete test. The 2-step test provided a safe, rapid, and low-cost method to diagnose insulin resistance in horses in a clinical setting.
Publisher: Wiley
Date: 11-03-2021
DOI: 10.1111/JVIM.16095
Abstract: Endocrinopathic laminitis develops in association with insulin dysregulation, but the role of insulin in the pathogenesis remains unclear. Hyperinsulinemia can cause hypoaminoacidemia, which is associated with integumentary lesions in other species and therefore warrants investigation as a potential mechanism in laminitis. Evaluate plasma amino acid concentrations in the euglycemic‐hyperinsulinemic cl (EHC) and prolonged glucose infusion (PGI) laminitis models. Sixteen Standardbred horses. Prospective experimental study. Plasma amino acid concentrations were measured in s les collected every 6 hours from horses that underwent a 48‐hour EHC (n = 8) or 66‐hour PGI (n = 8) after a 24‐ or 6‐hour baseline period in EHC and PGI groups, respectively. Fifteen of the 20 measured amino acid concentrations decreased over time in both EHC and PGI horses ( P 0.001). The median percentage change from baseline for these amino acids was: histidine (EHC: 41.5% PGI: 43.9%), glutamine (EHC: 51.8% PGI: 35.3%), arginine (EHC: 51.4% PGI: 41%), glutamic acid (EHC: 52.4% PGI: 31.7%), threonine (EHC: 62.8% PGI: 25.2%), alanine (EHC: 48.9% PGI: 19.5%), proline (EHC: 56.2% PGI: 30.3%), cystine (EHC: 34.9% PGI: 31.2%), lysine (EHC: 46.4% PGI: 27.8%), tyrosine (EHC: 27.5% PGI: 16.9%), methionine (EHC: 69.3% PGI: 50.8%), valine (EHC: 50.8% PGI: 34.4%), isoleucine (EHC: 60.8% PGI: 38.7%), leucine (EHC: 48.2% PGI: 36.6%), and phenylalanine (EHC: 16.6% PGI: 12.1%). Hypoaminoacidemia develops in EHC and PGI laminitis models. The role of hypoaminoacidemia in the development of hyperinsulinemia‐associated laminitis warrants further investigation.
Publisher: Wiley
Date: 04-12-2021
DOI: 10.1111/EVE.13372
Abstract: A 3‐day‐old Australian Stock Horse filly presented with fulminant acute kidney injury after receiving 4 g of intravenous oxytetracycline at 24 and 48 h of age for medical management of flexural deformities. The filly’s clinical status initially improved, but worsening azotaemia prompted euthanasia after 55 h of supportive care. Necropsy confirmed proximal tubular necrosis. Nephropathy in association with oxytetracycline administration has been rarely reported. This case describes severe nephropathy in an apparently normal foal and highlights the need for thorough case evaluation prior to use of high‐dose oxytetracycline therapy for correction of flexural deformities in foals.
Publisher: Wiley
Date: 20-12-2018
DOI: 10.1111/VSU.13137
Abstract: To evaluate a prototype dynamic laryngoplasty system (DLPS) in a static airflow model. Experimental. Ten equine larynges. The right arytenoid was fixed in abduction in all specimens. A left-sided laryngoplasty was performed with No. 2 Fiberwire and a FASTakII anchor. Each larynx was tested in a static airflow model. The system was adjusted to a flow rate of 55 L/s and prelaryngeal pressure of 12 mm Hg prior to testing in maximal arytenoid abduction. In phase 1, the left suture was loosened, shortened, and tested in 3-mm steps from 0 to 30 mm. In phase 2, the suture was tied with the DLPS in position at a target left-to-right quotient angle (LRQ) of 0.5. The DLPS was activated to target psi of 0, 25, and 50 for testing. Translaryngeal impedance (TLI), LRQ, cross-sectional areas (CSA), and resultant change in LRQ and CSA between, before, and during airflow testing were calculated. In phase 1, TLI was reduced by suture shortening up to 6 mm (P = .001) but not by additional shortening (P > .05). In phase 2, activation of the DLPS reduced the TLI from 0 psi (0.43 ± 0.08 mm Hg/L/s) to 25 psi (0.16 ± 0.04 mm Hg/L/s, P < .001), but no further reduction was detected at maximal psi (P = .10). Activation of the DLPS effectively reduced TLI. These results justify further investigation of the DLPS to assess its clinical applicability.
Publisher: Wiley
Date: 25-02-2023
DOI: 10.1111/JVIM.16650
Abstract: Sirolimus, a mechanistic target of rapamycin inhibitor, suppresses insulin production in other species and has therapeutic potential for hyperinsulinemia in horses. Determine the pharmacokinetics (PKs) of sirolimus and evaluate its effect on insulin dynamics in healthy and insulin dysregulation (ID) horses. Eight Standardbred geldings. A PK study was performed followed by a placebo‐controlled, randomized, crossover study. Blood sirolimus concentrations were measured by liquid chromatography‐mass‐spectrometry. PK indices were estimated by fitting a 2‐compartment model using nonlinear least squares regression. An oral glucose test (OGT) was conducted before and 4, 24, 72, and 144 hours after administration of sirolimus or placebo. Effects of time, treatment and animal on blood glucose and insulin concentrations were analyzed using mixed‐effects linear regression. Sirolimus was then administered to 4 horses with dexamethasone‐induced ID and an OGT was performed at baseline, after ID induction and after 7 days of treatment. Median (range) maximum sirolimus concentration was 277.0 (247.5‐316.06) ng/mL at 5 (5‐10) min and half‐life was 3552 (3248‐4767) min. Mean (range) oral bioavailability was 9.5 (6.8‐12.4)%. Sirolimus had a significant effect on insulin concentration 24 hours after a single dose: median (interquartile range) insulin at 60 min (5.0 [3.7‐7.0] μIU/mL) was 37 (−5 to 54)% less than placebo (8.7 [5.8‐13.7] μIU/mL, P = .03) and at 120 min (10.2 [8.4‐12.2] μIU/mL) was 28 (−15 to 53)% less than placebo (14.9 [8.4‐24.8] μIU/mL, P = .02). There was minimal effect on glucose concentration. Insulin responses decreased toward baseline in ID horses after 7 days of treatment. Sirolimus decreased the insulinemic response to glucose and warrants further investigation.
Publisher: Wiley
Date: 07-02-2019
DOI: 10.1111/EVJ.13072
Abstract: Continuous digital hypothermia can prevent the development and progression of laminitis associated with sepsis but its effects on laminitis due to hyperinsulinaemia are unknown. To determine the effects of continuous digital hypothermia on laminitis development in the euglycaemic hyperinsulinaemic cl model. Randomised, controlled (within subject), blinded, experiment. Eight clinically normal Standardbred horses underwent laminitis induction using the euglycaemic hyperinsulinaemic cl model (EHC). At initiation of the EHC, one forelimb was continuously cooled (ICE), with the other maintained at ambient temperature (AMB). Dorsal lamellar sections (proximal, middle, distal) were harvested 48 h after initiation of the EHC and were analysed using histological scoring (0-3) and histomorphometry. Cellular proliferation was quantified by counting epidermal cell nuclei staining positive with an immunohistochemical proliferation marker (TPX2). Severe elongation and disruption of SEL with dermo-epidermal separation (score of 3) was observed in all AMB feet at one or more section locations, but was not observed in any ICE sections. Overall 92% of the AMB sections received the most severe histological score (grade 3) and 8% were grade 2, whereas ICE sections were classified as either grade 1 (50%) or grade 2 (50%). Relative to AMB feet, ICE sections were 98% less likely to exhibit grades 2 or 3 (OR: 0.02, 95% CI 0.001, 0.365 P<0.01). Histomorphometry measurements of total and nonkeratinised primary epidermal lamellar length were significantly increased (P<0.01) in AMB limbs compared with ICE. TPX2 positive cell counts were significantly increased (P<0.01) in AMB limbs compared with ICE. Continuous digital hypothermia was initiated before recognition of laminitis and therefore the clinical applicability requires further investigation. Continuous digital hypothermia reduced the severity of laminitis in the EHC model and prevented histological lesions compatible with lamellar structural failure.
Publisher: MDPI AG
Date: 20-03-2021
DOI: 10.3390/ANI11030891
Abstract: Although there are many hormonal changes associated with reproduction, the effects of ovulation and early pregnancy on adrenocorticotropic hormone (ACTH) and insulin concentrations are poorly described. We hypothesise that both ovulation and early pregnancy will alter ACTH and insulin concentrations in healthy mares. Eighteen mares showing no clinical signs suggestive of, or laboratory findings consistent with, pituitary pars intermedia dysfunction PPID and insulin dysregulation (ID) are enrolled. ACTH, cortisol, insulin and glucose concentrations are measured over their peri-ovulatory period, as determined via ultrasounds and progesterone concentrations. The mares are grouped by age and gestation status, and a two-way repeated-measures ANOVA is used to determine the effects of age and early pregnancy, along with the peri-ovulatory period, on analyte concentrations. No significant effect of age, ovulation or early pregnancy is detected on the mares’ cortisol, insulin or glucose concentrations however, there is a significant effect of early pregnancy and ovulation on ACTH concentrations (p = 0.04 and p = 0.04 respectively). ACTH concentrations change around ovulation and with early pregnancy. Therefore, knowledge of a mare’s reproductive status might be beneficial when interpreting ACTH concentrations.
Publisher: Wiley
Date: 30-08-2023
DOI: 10.1111/EVJ.13991
Abstract: The thyrotropin‐releasing hormone (TRH) stimulation test is used to diagnose pituitary pars intermedia dysfunction (PPID) using 10‐ or 30‐min protocols. Imprecise s ling time for the 10‐min protocol can lead to misdiagnoses. To determine the effect of imprecise s ling time for the 30‐min protocol of the TRH stimulation test. In vivo experiment. Plasma immunoreactive adrenocorticotropin (ACTH) concentrations were measured 9, 10, 11, 29, 30 and 31 min after intravenous administration of 1 mg of TRH in 15 control and 12 PPID horses. Differences in ACTH concentrations between s ling times, variability in ACTH concentrations between protocols, and diagnostic classification of PPID were assessed using Friedman's test, Bland–Altman plots, and Fisher's exact test, respectively, with 95% confidence intervals reported and significance set at p 0.05. Imprecise s ling time resulted in variable ACTH concentrations, but significant differences in absolute ACTH concentrations were not detected for imprecise s ling within each protocol or between protocols. Imprecise s ling changed PPID diagnostic classification for 3/27 (11 [4–28] %) horses for both protocols. Using the 30‐min protocol as a reference, 1/12 (8 [1–35] %) horses returned a negative test result and 5/12 (42 [19–68] %) horses returned equivocal test results that would be considered positive in practice due to the presence of supportive clinical signs. Limited s le size and inter‐horse variability reduced the ability to detect small but potentially relevant differences. Overall, the impact of imprecise s ling was not significantly different between the 10‐ and 30‐min TRH stimulation test protocols. However, diagnostic classification for PPID would have varied between the 10‐ and 30‐min protocols in this population, if clinical signs had been ignored. Precise timing during TRH stimulation tests and contextual interpretation of ACTH concentrations remain fundamental for the diagnosis of PPID.
Publisher: SAGE Publications
Date: 28-11-2020
Abstract: Prudent use of antimicrobials is paramount to slow the development of resistance and for successful treatment. The use of cumulative antibiograms will allow evidence-based antimicrobial selection with consideration of local resistance patterns. We generated a “first-isolate-per-patient” cumulative antibiogram for a regional equine referral hospital. Bacterial organisms cultured from horses between 2011 and 2018, s le origin, antimicrobial susceptibilities, and multidrug-resistant (MDR) status were tabulated. Of 1,176 s les, 50% were culture positive. Overall, 93 of 374 (25%) were MDR. Of the MDR isolates, 11 (12%) were susceptible to high-importance antimicrobials only (as defined by the Australian Strategic and Technical Advisory Group on antimicrobial resistance). β-hemolytic streptococci were uniformly susceptible to penicillin (76 of 76) 17 of 20 (85%) non–β-hemolytic Streptococcus spp. were susceptible to penicillin. Despite veterinary-specific challenges in constructing an antibiogram, our study provides an exemplar of the clinical utility of regional-, farm-, or hospital-specific cumulative antibiograms for evidence-based empirical antimicrobial selection by veterinarians prior to susceptibility result availability.
Publisher: Wiley
Date: 16-03-2020
DOI: 10.1136/VR.105607
Publisher: MDPI AG
Date: 28-01-2022
DOI: 10.3390/ANI12030324
Abstract: Pituitary pars intermedia dysfunction (PPID) is diagnosed by increased basal or post thyrotropin-releasing hormone (TRH) stimulation ACTH concentrations. ACTH is known to be unstable however, the effect of different temperatures and TRH stimulation on equine ACTH stability is poorly described. In total, 15 horses, including 8 PPID positive (ACTH 35 pg/mL at baseline or pg/mL 30 min after TRH stimulation), were ided into 2 groups: 9, including 5 PPID positive, with basal ACTH concentrations and 6, including 3 PPID positive, with post TRH stimulation ACTH concentrations. Whole blood was stored for 1 h at 4, 20, 30, 40, or 70 °C. After centrifugation, immunoreactive ACTH concentrations were determined using a chemiluminescent assay. Linear mixed effect models were used to detect the effects of temperature, PPID status, and TRH stimulation on the immunoreactive ACTH concentration. Temperature had a significant effect (p = 0.003) on immunoreactive ACTH concentrations, and this effect was greater in PPID-negative horses (p = 0.01), with the changes in immunoreactive ACTH concentrations being slightly unpredictably higher or lower than s les stored at 4 °C. Even at 20 °C, mean immunoreactive ACTH concentrations minimally changed by 5% in PPID horses and 12% in non-PPID horses after 1 h. No significant effect of TRH stimulation was identified. Although ACTH concentrations should ideally be determined from s les kept at 4 °C, s les inadvertently left at temperatures of up to 40 °C can provide valid results if analyzed within 1 h however, this increases the risks of altered ACTH concentrations, occasionally influencing the diagnosis of PPID.
Publisher: SPIE-Intl Soc Optical Eng
Date: 05-10-2016
Publisher: Wiley
Date: 12-02-2020
DOI: 10.1111/EVJ.13215
Abstract: Continuous digital hypothermia (CDH) prevents lamellar failure in the euglycaemic hyperinsulinaemic cl (EHC) and oligofructose (OF) laminitis models, but the mechanisms remain unclear. To evaluate the effects of CDH on lamellar energy metabolism and perfusion in healthy horses and during EHC and OF laminitis models. In vivo experiment. Archived s les were used from Standardbred geldings that received no treatment (CON) (n = 8) or underwent EHC (n = 8) or OF (n = 6) laminitis models. Both forelimbs were instrumented with a lamellar microdialysis system, and one forelimb was cooled (CDH) with the other maintained at ambient temperature (AMB). Microdialysate was collected every 6 hours and analysed for glucose, lactate and pyruvate concentrations and lactate to pyruvate ratio (L:P). Microdialysis urea clearance was used to estimate lamellar tissue perfusion. Data were analysed using a mixed-effects linear regression model. Glucose did not change in CDH limbs relative to AMB in CON (P = .3), EHC (P = .3) or OF (P = .6) groups. There was a decrease in lactate (P < .001) and pyruvate (P < .01) in CDH limbs relative to AMB in all groups. L:P decreased in CON CDH relative to CON AMB (P < .001) but was not different in EHC (P = .6) and OF (P = .07) groups. Urea clearance decreased in CDH limbs relative to AMB in CON (P = .002) and EHC (P < .001), but not in OF (P = .4). The EHC model may not mimic natural endocrinopathic laminitis. CDH caused a marked decrease in lamellar glucose metabolism (CON, EHC and OF) and perfusion (CON and EHC) without affecting lamellar glucose concentration. Although cellular energy failure is not a primary pathophysiological event in EHC and OF laminitis models, CDH may act by limiting energy supply to pathologic cellular processes whilst preserving those critical to lamellar homoeostasis.
Publisher: Wiley
Date: 25-06-2020
DOI: 10.1111/JVIM.15835
Publisher: Wiley
Date: 09-2019
DOI: 10.1111/JVIM.15617
Abstract: The thyrotropin‐releasing hormone (TRH) stimulation test and the 2‐step insulin sensitivity test are commonly used methods to diagnose, respectively, pituitary pars intermedia dysfunction (PPID) and insulin dysregulation (ID). To investigate the diagnostic value of combining the TRH stimulation test and the 2‐step insulin sensitivity test to diagnose PPID and ID simultaneously. Twenty‐seven adult horses, 10 control horses without PPID or ID, 5 horses with PPID only, 5 horses with ID only, and 7 horses with PPID and ID. Randomized prospective study. Horses underwent a TRH stimulation test alone, a 2‐step insulin sensitivity test alone, and combined testing with simultaneous TRH and insulin injection in the same syringe. Data were compared by 2‐way repeated measures analysis of variance and 2 1‐sided tests to demonstrate equivalence. Bland‐Altman plots were generated to visualize agreement between combined and independent testing. The effect of combined testing on plasma adrenocorticotropic hormone, blood glucose concentration, or percentage decrease in blood glucose concentration was not significantly different from the effect obtained with independent testing. One control horse appeared falsely positive for PPID, 2 PPID‐only horses appeared falsely positive for ID, and 1 PPID and ID horse appeared falsely negative for ID when tests were performed simultaneously. Bland‐Altman plots supported the agreement between combined and independent testing. Combining the TRH stimulation test and the 2‐step insulin sensitivity test appears to be a useful diagnostic tool for equine practitioners in the field, allowing testing of a horse for both PPID and ID simultaneously.
Publisher: Wiley
Date: 12-06-2013
DOI: 10.1111/JVIM.12124
Abstract: Arsenic toxicosis is uncommon in cattle and successful treatment is rarely reported. This analysis reviews all cases of acute arsenic toxicosis in cattle reported in the literature and describes cases from Purdue University that had a favorable outcome. Clinical presentation of the disease, treatments, and variables associated with survival are described. One hundred and fifty-six cattle with arsenic toxicosis from 16 outbreaks. Meta-analysis. The most common clinical signs were sudden death (68%), diarrhea (33%), ataxia (29%), dehydration (22%), and respiratory distress (4%). The most common clinicopathologic abnormalities included azotemia (100%), hematuria (100%), increased liver enzyme activity (86%), and increased hematocrit (60%). One percent of cattle survived and the survival time for nonsurvivors ranged from 20 hours to 21 days. None of the clinical signs or clinicopathologic findings was associated with survival. Treatment was attempted in 24% of cases and was not associated with survival (P = .055), but administration of an antidote and administration of fluids were associated with better outcome (P = .036 and P = .009, respectively). In the animals presented to Purdue University, treatment with IV fluids and sodium thiosulfate resulted in decreased blood arsenic concentrations in all animals (P = .009) and a survival rate of 50%. Although acute arsenic toxicosis has a poor prognosis, survival is possible if aggressive fluid therapy and antidotes are administered.
Publisher: American Veterinary Medical Association (AVMA)
Date: 12-2013
Abstract: Objective —To evaluate the effect of ovariectomy on insulin sensitivity in horses and determine whether the effects of suppression of the hypothalamo-pituitary-adrenal axis differ before and after ovariectomy. Animals —6 healthy mares. Procedures —The horses underwent an IV glucose tolerance test (IVGTT), an insulin sensitivity test, and a dexamethasone suppression test before and 5 weeks after ovariectomy. Body weight, serum cortisol and plasma ACTH concentrations, serum insulin-to-blood glucose concentration ratios, and changes in blood glucose concentration with time after injection of glucose or insulin were compared before and after ovariectomy. Results —The dexamethasone injection resulted in a decrease in serum cortisol concentration before and after ovariectomy. In all horses, baseline plasma ACTH concentrations were within the reference range before and after ovariectomy. For each mare, results of an IVGTT before and after ovariectomy were considered normal. No significant differences in basal blood glucose concentration or time to reach baseline glucose concentration after an IVGTT were observed. Basal serum insulin concentration and serum insulin-to-blood glucose concentration ratios were not significantly different before or after ovariectomy, nor was the mean time to attain a 50% decrease in blood glucose concentration after insulin injection. Conclusions and Clinical Relevance —Results indicated that ovariectomy does not appear to modify dexamethasone response in horses and that it does not modify short-term measures of insulin sensitivity. Findings suggested that horses undergoing ovariectomy are not at higher risk of developing equine metabolic syndrome or hypothalamo-pituitary-adrenal axis dysfunction and associated morbidity.
Publisher: Wiley
Date: 23-06-2017
DOI: 10.1111/EVJ.12703
Abstract: Insulin dysregulation is the hallmark of equine metabolic syndrome and has received attention because of its direct association with laminitis. In the absence of an adequate treatment for laminitis, a focus on prophylaxis is needed, making early detection of in iduals at risk of developing laminitis one of the main challenges in equine endocrinology. Recent studies have shown that insulin dysregulation goes beyond tissue insulin resistance and it is now demonstrated that the equine enteroinsular axis plays a major role in insulin secretion and equine hyperinsulinaemia. In this review, we discuss the different tests currently available to diagnose insulin dysregulation in horses: the ones investigating tissue insulin resistance and those investigating the enteroinsular axis, detailing their goals, practicalities and limitations. This review supports the contention that the diagnosis of equine insulin dysregulation should now be based on the investigation of both tissue insulin resistance and the equine enteroinsular axis. Regardless of the tests used many factors of variation, such as breed, diet, fasting state or season, have been identified and could potentially confound the results of a specific test. Therefore, careful interpretation of the results of a given test in each in idual situation is required to optimise the detection of horses at risk of laminitis.
Publisher: Wiley
Date: 21-02-2022
DOI: 10.1111/AVJ.13155
Abstract: Upper airway endoscopy of thoroughbred (TB) yearlings is commonly used in an attempt to predict laryngeal function (LF) and its impact on future race performance. The aim of this study was to determine if different grading systems and laryngeal grades were correlated with future performance. Postsale endoscopic recordings were obtained from an Australian TB yearling sale during a four‐year period from 2008 to 2011. Horses were included if they had a diagnostic postsale video endoscopic recording and raced within Australia. Recordings were graded using the Havemeyer system and subsequently recategorised according to the Lane scale and two condensed scales. Performance data were sourced from Racing Australia and comparisons were made between groups. A total of 1244 horses met the inclusion criteria. There were no significant differences in sex or sales price between groups. There were no significant differences in the number of starts or wins between groups for any grading system. For the condensed Havemeyer scale, horses with intermediate LF were separated into two groups. Significant differences in earnings were found between ‘normal’ and ‘abnormal’ (P = 0.02) and ‘intermediate‐low’ and ‘abnormal’ grades (P = 0.03). There were no significant differences between horses with ‘intermediate‐high’ and ‘abnormal’ grades (P = 0.40). No significant differences were found between the two intermediate grades (P = 0.60) or between horses with normal LF and either ‘intermediate‐low’ or ‘intermediate‐high’ grades (P = 0.99). Resting LF in Australian yearling TBs assessed using a condensed Havemeyer grading scale had some predictive value for future racing performance. This information should be considered when performing yearling endoscopic examinations.
Publisher: Elsevier BV
Date: 12-2015
DOI: 10.1111/JTH.13156
Abstract: Growth arrest-specific 6 (Gas6)-deficient mice are protected against venous thromboembolism (VTE), suggesting a role for Gas6 in this disorder. We previously demonstrated that Gas6 induces forkhead box O1 (FoxO-1) phosphorylation through the phosphoinositide 3-kinase-Akt pathway. FoxO-1 regulates the expression of vascular cell adhesion molecule-1 (VCAM-1), a molecule that has been implicated in VTE. To assess the role of FoxO-1 in Gas6-dependent VCAM-1 expression. Thrombin was used to stimulate endothelial cells (ECs). Wild-type (WT) and Gas6(-/-) ECs were transfected with small interfering RNA targeting Axl or FoxO-1, a luciferase-coupled plasmid containing the FoxO-1 consensus sequence, and a phosphorylation-resistant FoxO-1 mutant, or treated with an Akt inhibitor. VCAM-1 mRNA expression was measured by real time-qPCR. VCAM-1 protein expression and FoxO-1 and Akt phosphorylation were assessed by western blot analysis. FoxO-1 localization was assessed by immunofluorescence. Adhesion of bone marrow mononuclear cells (BM-MCs) on ECs was assessed by fluorescence. Thrombin induces both VCAM-1 expression and FoxO-1 phosphorylation and nuclear exclusion in WT ECs only. Silencing of FoxO-1 enhances VCAM-1 expression in both WT and Gas6(-/-) ECs. Inhibition of Akt or FoxO-1 phosphorylation prevents VCAM-1 expression in WT ECs. These data show that Gas6 induces FoxO-1 phosphorylation, leading to derepression of VCAM-1 expression. BM-MC-EC adhesion is increased by thrombin in WT ECs. BM-MC-EC adhesion is further increased when FoxO-1 is silenced, but decreased when FoxO-1 phosphorylation is inhibited. These results demonstrate that the Gas6-FoxO-1 signaling axis plays an important role in VCAM-1 expression in the context of VTE by promoting BM-MC-EC adhesion.
Publisher: Wiley
Date: 10-2013
DOI: 10.1111/JVIM.12209
Abstract: The epidemiology of equine neorickettsiosis (EN) has been extensively studied but limited clinical and clinicopathological data are available concerning naturally infected horses. Factors predictive of survival will be identified in horses diagnosed with EN. Convenience s le of 44 horses with EN admitted to 2 referral institutions. A retrospective study was performed. A diagnosis of EN was based on the presence of positive blood or fecal PCR. The most common clinical signs included diarrhea (66%), fever (50%), anorexia (45%), depression (39%), colic (39%), and lameness (18%). The median duration of hospitalization was 6 days and 73% of horses survived to discharge. Laminitis was present in 36% of horses, 88% of which were affected in all 4 feet. Serum creatinine and urea nitrogen concentrations, as well as RBC count, blood hemoglobin concentration, hematocrit, band neutrophils, serum AST activity, serum CK activity, and anion gap, were significantly (P < .05) higher in nonsurvivors. Serum chloride and sodium, concentrations as well as duration of hospitalization were significantly lower in nonsurvivors. The results of forward stepwise logistic regression indicated that blood hemoglobin concentration on admission and antimicrobial treatment with oxytetracycline were independent factors associated with survival. Severity of colitis as reflected by electrolyte loss, hemoconcentration, and prerenal azotemia were predictors of survival in horses diagnosed with EN. Treatment with oxytetracycline was associated with increased survival.
Publisher: Wiley
Date: 07-05-2016
DOI: 10.1111/JVIM.13958
Publisher: Wiley
Date: 10-05-2018
DOI: 10.1111/JVIM.15138
Publisher: Wiley
Date: 02-08-2016
DOI: 10.1111/JVIM.14529
Abstract: Published descriptions of the oral sugar test (OST) and insulin response test (IRT) have been inconsistent when specifying the protocol for fasting horses before testing. The purpose of our study was to examine the effect of fasting duration on blood glucose concentration, blood insulin concentration, glucose/insulin ratio, OST, and IRT results in horses. Ten healthy adult horses. Both OST and IRT were performed on horses without fasting and after fasting for 3, 6, and 12 hours. Thus, 8 tests were performed per horse in a randomized order. Blood collected at the initial time point of the OST was analysed for both blood glucose and serum insulin concentrations so that baseline concentrations and the glucose/insulin ratio could be determined. Unless fasted, horses had free-choice access to grass hay. There was no effect of fasting and fasting duration on blood glucose concentration, serum insulin concentration, glucose/insulin ratio, or the OST. Response to insulin in the IRT was decreased in fasted horses. The effect increased with fasting duration, with the least response to insulin administration after a 12-hour fast. These data indicate that insulin sensitivity is not a fixed trait in horses. Fasting a horse is not recommended for a glucose/insulin ratio or IRT, and fasting a horse for 3 hours is recommended for the OST.
Publisher: Wiley
Date: 08-2020
DOI: 10.1111/AVJ.12963
Publisher: Wiley
Date: 05-2023
DOI: 10.1111/JVIM.16723
Abstract: The HMGA2 :c.83G A variant was identified in Welsh ponies having pleiotropic effects on height and insulin concentration. Determine whether the HMGA2 :c.83G A variant is associated with decreased height and higher basal insulin concentrations across pony breeds. Two hundred thirty‐six ponies across 6 breeds. Cross‐sectional study. Ponies were genotyped for the HMGA2 :c.83G A variant and phenotyped for height and basal insulin concentrations. Stepwise regression was performed for model analysis using a linear regression model for height and mixed linear model for insulin with farm as a random effect. Coefficient of determination, pairwise comparison of the estimated marginal means and partial correlation coefficients (parcor) were calculated to assess the relationship between HMGA2 genotype and height or insulin. Breed and genotype accounted for 90.5% of the variation in height across breeds, and genotype explained 21% to 44% of the variation within breeds. Breed, genotype, cresty neck score, sex, age, and farm accounted for 45.5% of the variation in insulin, with genotype accounting for 7.1%. The HMGA2 A allele frequency was 62% and correlated with both height (parcor = −0.39 P .001) and insulin (parcor = 0.22 P = .02). Pairwise comparisons found A/A ponies were cm shorter than other genotypes. Compared with G/G in iduals, A/A and G/A in iduals had 4.3 μIU/mL (95% confidence interval [CI]: 1.8‐10.5) and 2.7 μIU/mL (95% CI: 1.4‐5.3) higher basal insulin concentrations, respectively. These data demonstrate the pleiotropic effects of the HMGA2 :c.83G A variant and its role in identifying ponies at increased risk for insulin dysregulation.
Publisher: Wiley
Date: 13-10-2021
DOI: 10.1111/JVIM.16281
Abstract: Pituitary pars intermedia dysfunction (PPID) is a common endocrinopathy of horses diagnosed with a thyrotropin‐releasing hormone (TRH) stimulation test. Describe the repeatability of TRH stimulation in horses with and without PPID in winter and autumn. Twenty adult horses 6 controls and 6 with PPID tested in autumn, 8 controls and 6 with PPID tested in winter with 3 controls and 3 with PPID tested in both seasons. Thyrotropin‐releasing hormone stimulation was performed on 2 consecutive occasions, 1 week before and 1 week after the winter solstice and the autumn equinox. Blood was collected before and 30 minutes after IV injection of 1 mg of TRH. ACTH concentration was determined by a chemiluminescent assay. Repeatability and test‐retest reliability were assessed by repeated measures analysis of variance, intraclass correlation coefficient and within‐horse coefficients of variation (CV). Bland‐Altman plots were generated to visualize agreement between repetitions. In winter, no week effect was detected on the results of the TRH simulation and the test had an excellent test‐retest reliability. In autumn, after‐TRH ACTH concentrations were significantly lower on week 2 ( P = .02) and the test only had a good test‐retest reliability. There were significantly larger within‐horse CV during autumn ( P = .04) and after TRH stimulation ( P = .04). There were 2 misclassifications in winter and 4 in autumn. The TRH stimulation test was repeatable when performed 2 weeks apart in winter however, in autumn, more variability in after‐TRH ACTH concentrations resulted in decreased repeatability.
Publisher: Wiley
Date: 03-12-2018
DOI: 10.1111/EVJ.13041
Abstract: Pituitary pars intermedia dysfunction (PPID) is a commonly described endocrine disorder in higher latitudes of the Northern hemisphere but the description of the disease at lower latitudes and in the Southern hemisphere is limited. Document the clinical features of PPID at different Australian latitudes and climates, and investigate factors associated with survival, laminitis and insulin dysregulation (ID). Retrospective study of 274 equids from eight institutions across Australia. A diagnosis of PPID was based on endogenous ACTH, overnight dexamethasone suppression test, thyrotropin-releasing hormone stimulation test or necropsy. Clinical and clinicopathologic characteristics of PPID and therapeutic responses were investigated. Laminitis was diagnosed by radiographic or histologic changes and ID was diagnosed based on endogenous insulin, an oral glucose test or a 2-step insulin-response test. Being a pony, having a higher body condition score and pergolide administration were associated with survival. The clinical presentation of PPID changed with latitude and climate, with anhidrosis and polyuria olydipsia more commonly recognised at lower latitudes. Laminitis was diagnosed in 89.9% of cases and ID was present in 76.5% of cases in which they were investigated. Despite the s le size, the lack of uniform testing at all locations (primary or referral cases) and the incompleteness of data sets limited the power of the statistical analyses. PPID can present with variable signs at different latitudes and climates, and ID should be investigated in equids diagnosed with PPID. Adequate body condition and administration of pergolide are fundamental in PPID management.
Publisher: Wiley
Date: 07-04-2020
DOI: 10.1111/JVIM.15771
Abstract: Determination of plasma adrenocotrophic hormone (ACTH) concentration (endogenous or thyrotropin‐releasing hormone [TRH] stimulation test) is the most commonly used diagnostic test for pituitary pars intermedia dysfunction (PPID) in horses. Because ACTH is unstable, s les often are frozen to be shipped to laboratories or to allow for batch analysis of research s les. However, the effect of multiple freeze‐thaw cycles on equine ACTH is unknown. To determine the effects of multiple freeze‐thaw cycles on immunoreactive ACTH concentration. Twenty‐eight horses ranging from 10 to 27 years of age were used. Prospective study. Horses were ided into 4 groups: group 1, PPID‐negative, without TRH stimulation group 2, PPID‐negative, with TRH stimulation group 3, PPID‐positive, without TRH stimulation and group 4, PPID‐positive, with TRH stimulation. Whole blood was collected from each horse at baseline or 30 minutes after TRH stimulation. Immunoreactive plasma ACTH concentration was determined using a chemiluminescence assay. Plasma s les then were frozen at −80°C hours, thawed at 4°C and reanalyzed for 5 freeze‐thaw cycles. Changes in plasma ACTH concentration were analyzed using a linear mixed‐effect model. Significant effects of freeze‐thaw cycles ( P = .001) and PPID status ( P = .04) on plasma ACTH concentration were observed, but no significant effect of TRH stimulation was identified. The plasma ACTH concentration is altered by freeze‐thaw cycles, and the effect is observed sooner in horses with PPID. To diagnose PPID, multiple freeze‐thaw cycles should be avoided when measuring plasma ACTH concentration.
Publisher: Wiley
Date: 03-08-2023
DOI: 10.1111/EVJ.13981
Abstract: Equine thyroid disorders pose a diagnostic challenge in clinical practice because of the effects of nonthyroidal factors on the hypothalamic–pituitary–thyroid axis, and the horse's ability to tolerate wide fluctuations in thyroid hormone concentrations and survive without a thyroid gland. While benign thyroid tumours are common in older horses, other disorders like primary hypothyroidism or hyperthyroidism in adult horses and congenital hypothyroidism in foals are rare. There is a common misunderstanding regarding hypothyroidism in adult horses, especially when associated with the clinical profile of obesity, lethargy, and poor performance observed in dogs and humans. Low blood thyroid hormone concentrations are often detected in horses as a secondary response to metabolic and disease states, including with the nonthyroidal illness syndrome however, it is important to note that low thyroid hormone concentrations in these cases do not necessarily indicate hypothyroidism. Assessing equine thyroid function involves measuring thyroid hormone concentrations, including total and free fractions of thyroxine (T4) and triiodothyronine (T3) however, interpreting these results can be challenging due to the pulsatile secretion of thyroid hormones and the many factors that can affect their concentrations. Dynamic testing, such as the thyrotropin‐releasing hormone stimulation test, can help assess the thyroid gland response to stimulation. Although true hypothyroidism is extremely rare, thyroid hormone supplementation is commonly used in equine practice to help manage obesity and poor performance. This review focuses on thyroid gland pathophysiology in adult horses and foals, interpretation of blood thyroid hormone concentrations, and evaluation of horses with thyroid disorders. It also discusses the use of T4 supplementation in equine practice.
Publisher: Wiley
Date: 10-05-2019
DOI: 10.1111/EVJ.13120
Abstract: Primary hyperparathyroidism is uncommon in equids. To describe the diagnostic findings and efficacy of treatment in equids with primary hyperparathyroidism. Retrospective case series describing 16 horses and one mule. Cases were identified by retrospective review of records at Cornell University and via an ACVIM listserv query. Inclusion criteria were an equid with hypercalcemia, normal renal function and high parathyroid hormone (PTH) or histopathological diagnosis of a parathyroid adenoma. Equids with normal PTH and PTH-related protein (PTHrP) in the face of hypercalcemia were included as suspect cases. The most common presenting complaints were weight loss (12/17) and hypercalcemia (10/17). PTH was above reference range in 12/17 cases. Suspected parathyroid tumours were localised in 12/14 equids imaged using ultrasonography alone (2/3), technetium 99m Tc sestamibi scintigraphy alone (1/1) or both modalities (9/10). Three horses did not have imaging performed. Surgical exploration successfully excised tumours in six of 10 cases. Five were located at the thoracic inlet, and surgery resulted in complete cure. One tumour was excised from the thyroid lobe, and the horse remained hypercalcemic. Four other cases explored surgically, four treated medically and three that were not treated also remained hypercalcemic. The small study size prohibited statistical analysis. Parathyroid adenomas in equids can be successfully localised with ultrasonography and scintigraphy. Surgical excision appears more likely to be successful for single gland disease at the thoracic inlet.
Publisher: SAGE Publications
Date: 12-10-2016
Abstract: Postmortem findings in 241 equids admitted to a teaching hospital that were at least 15 years old at autopsy were reviewed (1) to determine disease prevalence, (2) to compare the cause of death (or euthanasia) in equids 15 to 19 years of age ( n = 116) with that in equids ≥20 years of age ( n = 125), and (3) to catalog coexisting lesions in equids with pituitary pars intermedia dysfunction (PPID). Breed and sex were evenly distributed between the age groups. Death or euthanasia was attributed to disease of the digestive system (41.5%), pituitary gland (12.9%), locomotor system (10.0%), nervous system (7.9%), cardiovascular system (4.6%), urinary system (4.6%), reproductive system (4.2%), respiratory system (4.2%), integumentary system (4.2%), lymphoid system (2.5%), liver (2.5%), or systemic neoplasia (1.2%). Nervous system disease was more common in the 15- to 19-year group urinary tract disease was more common in the ≥20-year group. Neoplastic disease, regardless of systemic location, was the basis for death or euthanasia in 18.7% of all equids. Squamous cell carcinoma, lymphoma, and melanoma were the most common malignant neoplasms. PPID was the most common specific diagnosis, based on the postmortem presence of hyperplasia or adenoma, and was the reason for euthanasia in 47.7% of 65 equids with PPID. The most common nonpituitary causes for death or euthanasia in equids with PPID were colic, lameness, cancer, and spinal cord disease. Coexisting conditions in equids with PPID that were not considered the basis for euthanasia included neoplasms, infections, lameness, and recurrent airway obstruction.
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 07-2017
DOI: 10.1161/ATVBAHA.116.308925
Abstract: Coagulation and inflammation are inter-related. Gas6 (growth arrest–specific 6) promotes venous thrombosis and participates to inflammation through endothelial-innate immune cell interactions. Innate immune cells can provide the initiating stimulus for venous thrombus development. We hypothesize that Gas6 promotes monocyte recruitment during venous thrombosis. Deep venous thrombosis was induced in wild-type and Gas6-deficient (−/−) mice using 5% FeCl 3 and flow reduction in the inferior vena cava. Total monocyte depletion was achieved by injection of clodronate before deep venous thrombosis. Inflammatory monocytes were depleted using an anti–C-C chemokine receptor type 2 (CCR2) antibody. Similarly, injection of an anti–chemokine ligand 2 (CCL2) antibody induced CCL2 depletion. Flow cytometry and immunofluorescence were used to characterize the monocytes recruited to the thrombus. In vivo, absence of Gas6 was associated with a reduction of monocyte recruitment in both deep venous thrombosis models. Global monocyte depletion by clodronate leads to smaller thrombi in wild-type mice. Compared with wild type, the thrombi from Gas6 −/− mice contain less inflammatory (CCR2 hi CX 3 CR1 lo ) monocytes, consistent with a Gas6-dependent recruitment of this monocyte subset. Correspondingly, selective depletion of CCR2 hi CX 3 CR1 lo monocytes reduced the formation of venous thrombi in wild-type mice demonstrating a predominant role of the inflammatory monocytes in thrombosis. In vitro, the expression of both CCR2 and CCL2 were Gas6 dependent in monocytes and endothelial cells, respectively, impacting monocyte migration. Moreover, Gas6-dependent CCL2 expression and monocyte migration were mediated via JNK (c-Jun N-terminal kinase). This study demonstrates that Gas6 specifically promotes the recruitment of inflammatory CCR2 hi CX 3 CR1 lo monocytes through the regulation of both CCR2 and CCL2 during deep venous thrombosis.
Publisher: Wiley
Date: 12-02-2020
DOI: 10.1111/EVJ.13224
Abstract: Hyperinsulinaemia is associated with the development of endocrinopathic laminitis however, the mechanisms remain unclear. Evaluate the effects of hyperinsulinaemia on lamellar energy metabolism and perfusion during laminitis development. In vivo experiment. Eight Standardbred horses were instrumented with a microdialysis probe in the lamellae of a forelimb. A 24 hours baseline period (BASELINE) was followed by 48 hours of a continuous euglycaemic hyperinsulinaemic cl (EHC) from 24 to 72 hours (CLAMP). Microdialysate was collected every 6 hours and analysed for glucose, lactate and pyruvate concentrations and lactate-to-pyruvate ratio (L:P). Microdialysis urea clearance was used to estimate lamellar tissue perfusion. Archived microdialysis s les from six identically instrumented Standardbred horses served as controls (CON). Variables were compared over time and between EHC and CON horses using a mixed-effects linear regression model. Glucose concentration decreased during the CLAMP period in CON and EHC horses (P .9). Lactate concentration increased during the CLAMP period in CON and EHC horses (P < .001), however, the rate of increase was significantly higher in EHC horses relative to CON (P = .014). There was a relative increase in pyruvate concentration in EHC horses compared with CON during the CLAMP period (P = .03). L:P increased significantly in CON horses during the CLAMP period (P < .001) but not in EHC (P = .1). Urea clearance did not change in CON (P = .9) or EHC (P = .05) during the CLAMP, but did increase in EHC relative to CON (P = .02). The effects of microdialysis probe implantation on perfusion and metabolism remain unclear. The EHC model may not mimic natural endocrinopathic laminitis. Laminitis developed without evidence of lamellar hypoperfusion or energy stress. Therapies to improve perfusion are unlikely to affect the initial development of endocrinopathic laminitis.
No related grants have been discovered for François-René Bertin.