Pathophysiology in horses involves the study of functional changes that occur in the body as a result of disease or injury. This field examines the mechanisms through which diseases develop and progress, as well as how they affect the body's normal physiological processes. In equine research, pathophysiology encompasses a wide range of conditions, including respiratory disorders, musculoskeletal injuries, gastrointestinal diseases, and metabolic syndromes. Understanding these processes helps in identifying potential therapeutic targets and developing effective treatment strategies. This page collects peer-reviewed research studies and scholarly articles that explore the underlying mechanisms, clinical manifestations, and implications of various pathophysiological conditions in equine health.
Kaneko M, Oikawa M, Yoshihara T.Pathomorphological analysis was performed on fractured bones of 470 race horses. The most common fracture site was the limb (98% of cases), and the majority of fractures were intra-articular. Focal osteochondral lesions consisting of osteochondrosis, osteonecrosis and osteosclerosis were observed frequently in fractured and non-fractured bones. In the fractured bones, the lesions frequently appeared in the vicinity of the fractured site. Under the influence of antecedent osteochondrosis from the young stage, osteosclerotic and osteonecrotic lesions may have been induced by immoderate exercise ...
Simmons TR, Cook JA, Moore JN, Halushka PV.Thromboxane (TX) A2 has been implicated as an important pathophysiologic mediator of a variety of cardiovascular diseases. Monocytes synthesize TXA2 and it modulates their function. This study sought to characterize monocyte TXA2 receptors. Radioligand binding studies were performed on membranes prepared from equine peripheral blood monocytes using [125I]BOP, a TXA2 receptor agonist. [125I]BOP bound to a single class of binding sites (Kd = 1.0 +/- 0.3 nM and Bmax = 389 +/- 191 fmol/mg protein; n = 5). Several TXA2 receptor agonists and antagonists competed for binding with [125I]BOP. I-BOP pro...
Nasisse MP, Nelms S.Ulcerative keratitis is one of the most common vision-threatening diseases of the horse. Successful therapy, however, can be achieved in the majority of cases provided the diagnosis is made early and the treatment is specific for the disease. This article reviews the pathophysiology, clinical signs, and contemporary medical and surgical approaches to bacterial and fungal ulcerative keratitis in the horse.
Kotzé SH, Soley JT.Spirally arranged bundles of sub-endothelial smooth muscle enfold the small to medium-sized submucosal veins in the equine ileocecal junction. The muscle bundles, accompanied by the endothelial lining, bulge into the lumen of the vessels, partly occluding the latter. Transmission electron microscopy of the muscle cells reveals features consistent with vascular smooth muscle ultrastructure. It is proposed that the throttling effect of the muscle bundles causes engorgement of the submucosal venous plexus, which then assists in the closing of the ileocecal orifice.
Robinson JA, Marr CM, Reef VB, Sweeney RW.A Standardbred filly was admitted for evaluation of pleuritis and pneumonia. Heart rate was 80 to 120 beats/min, and the pulse was barely palpable. Thoracic and abdominal ultrasonography and echocardiography revealed substantial pericardial effusion with cardiac tamponade, fibrinous pericarditis, pleural effusion, and ascites. Initial electrocardiography revealed normal sinus rhythm with decreased amplitude of the QRS complexes consistent with pericardial effusion. Following thoracentesis, echocardiogram-guided pericardiocentesis was performed. Bacterial culture yielded no growth from any of t...
Stadler P, Weinberger T, Kinkel N, Deegen E.B- and M-mode echocardiography was performed on 38 horses. 34 patients had systolic heart murmur with the point of maximal intensity over mitral valve. Additionally, 17 of these patients were examined with the pulsed wave doppler echocardiography (Vingmed 200). In 26 patients with cardiac murmur and in 4 patients without cardiac murmur a mitral valve insufficiency was diagnosed by echocardiography. In 8 horses with a systolic murmur over mitral valve M- and B-mode evaluation could not reveal a haemodynamic importance of the murmur. The diagnosis of MVI was based on a dilation of left atrium wi...
Henninger DD, Snyder JR, Pascoe JR, Dilling GW.The normal microvascular permeability of the ascending colon in horses and the microvascular permeability of that segment after ischemia and reperfusion were investigated. Microvascular permeability was estimated by the ratio of lymphatic protein to plasma protein concentration (Cl/Cp) at high lymph flow rates in 8 adult horses in 2 equal groups: normal and ischemic (2-hour period). Lymphatic flow rates and lymph and plasma protein concentrations were determined. Intestinal biopsy specimens were obtained at the end of each experiment. Flow independent values were selected and compared by one-w...
Dixon PM.The structure and possible functions of respiratory secretions are reviewed. In the equine, goblet (mucus producing) cells are the main source but little information is available on the volume or composition of equine respiratory secretions. Airway mucus has complex and incompletely understood physical characteristics which can be partially assessed by a wide range of in vitro and biological techniques. The complex relationship between mucus structure and its propulsion by the airway cilia are discussed, both in health and with pulmonary disease. Mucokinesis in the horse has been assessed visu...
Caron JP, Bowker RM, Abhold RH, Toppin DS, Sonea IM, Vex KB.This preliminary study was designed to determine whether the neurotransmitter substance P was present in the middle carpal synovial membrane of the normal horse and whether the neuropeptide could be identified in the synovial fluid of normal horses and those with joint diseases. Immunocytochemistry on middle carpal synovial membrane biopsies from fresh cadavers was used to demonstrate substance P-containing neural elements. Substance P was most abundant in the subintimal portion of the membrane, with occasional filaments coursing via synovial fronds to the intimal portion. Radioimmunoassay tec...
Olsen SN.Five horses with squamous cell carcinoma of the stomach are described. The clinical findings included anorexia, weight loss, abdominal distension, abnormal chewing and swallowing behaviour and abdominal masses palpable per rectum in four cases. Haematological studies revealed a normocytic anaemia in three horses, and neutrophilia and hypoalbuminaemia in two. Analysis of peritoneal fluid revealed abnormal effusions in all five horses and neoplastic cells were identified in three of them. The tumours originated in the cardia and metastases were present in all the horses. Three of them had many s...
McGorum BC, Dixon PM.Horses with asymptomatic or symptomatic chronic obstructive pulmonary disease (COPD) and control horses were challenged with oil seed rape either by exposure to a field of flowering Brassica campestris for six days, or by an inhalation challenge with freshly collected pollen from Brassica napus, or by inhalation challenge with a commercial extract of B napus pollen. Clinical and bronchoscopic examinations showed that the challenges did not induce detectable pulmonary disease in the control or asymptomatic COPD affected horses and did not significantly affect their pulmonary mechanics, arterial...
Schusser GF, Obermayer-Pietsch B.The plasma gastrin levels in fasted horses (21.1 +/- 15.6 pg/ml), in horses with spasmodic colic (7.3 +/- 5.4 pg/ml) and in horses with impaction of the left ventral large colon and/or pelvic flexure (11.4 +/- 3.1 pg/ml) were not significantly different. The plasma gastrin concentrations of horses with strangulation obstruction of the small intestine, large colon displacement or adynamic ileus, and which had no gastric reflux, were 12.9 +/- 8.7 pg/ml and did not differ from fasted gastrin levels. Horses which had 5-10 litres of stomach content reflux had a higher mean gastrin level (32.2 +/- 2...
MacKay RJ, Lester GD.Because hepatocyte-stimulating factor/interleukin 6 (IL-6) is the principal inducer of acute-phase protein synthesis in the liver, quantification of its activity in blood provides an early and sensitive assessment of the acute-phase response. Circulating IL-6 activity was monitored in 4 adult horses for 72 hours after IV administration of endotoxin. In 4 experiments performed at weekly intervals and in randomized order, each horse was given endotoxin--1,000 30, 1, and 0 ng/kg of body weight. Plasma IL-6 activity was quantified as the ability to promote growth of the IL-6-dependent B-cell hybri...
Olson LE.We evaluated the pressure-flow relationships in collaterally ventilating segments of excised pony lungs by infusing N2, He, Ne, or SF6 at known flows (V) through a catheter wedged in a peripheral airway. Measurements were made at segment- (Ps) to-airway opening (Pao) pressure differentials of 3-15 cmH2O when the lungs were held at transpulmonary pressures of 5, 10, and 15 cmH2O. The data were analyzed both by calculating collateral resistance (Ps-Pao/V) and by constructing Moody-type plots of normalized pressure drop [(Ps-Pao)/(1/2 rho U2, where rho is density and U is velocity)] against Reyno...
Harrison LJ, May SA.A three-month-old foal was presented with subluxation of the proximal interphalangeal joint in both forelimbs. The condition, which was considered to represent an unusual manifestation of breakdown of the suspensory apparatus, appeared to have developed as a consequence of extreme overexertion, 10 days previously. This had resulted in rupture of the palmar supporting structures of the joint; namely, the superficial distal sesamoidean ligament, the insertion of the superficial digital flexor tendon and the palmar joint capsule. Severe laxity of the flexor tendons had been present in the neonata...
Doxey DL, Pogson DM, Milne EM, Gilmour JS, Chisholm HK.Damage to the neurons of selected autonomic ganglia was quantified in relation to the severity of the clinical signs shown in acute, subacute and chronic cases of dysautonomia (grass sickness). No connection between the clinical severity of acute or subacute dysautonomia and the amount of neuronal damage in the superior cervical, stellate and coeliaco-mesenteric ganglia could be demonstrated. However, a higher proportion of normal neurons were found in chronic cases. Jejunal submucosal neuronal damage was correlated with clinical severity but further work is required to confirm this finding an...
Drommer W, Damsch S, Winkelmeyer S, Hertsch B, Kaup FJ.In 25 adult horses the podotrochlea of 49 forelimbs was examined by means of light and electron microscopy in order to correlate clinical and morphological findings. According to the clinical diagnosis the animals were divided into three groups: lameness due to syndrome of podotrochlosis (group 1) or due to tendopathy (group 2) and horses without lameness (group 3). The most striking pathological findings of the navicular bone and the opposite surface of the deep flexor tendon were found in horses with podotrochlosis, consisting of loss of cartilage and tendon matrix with denudation of collage...
Fenger CK, Kohn CW.A 20-month-old Quarter Horse stallion was admitted for evaluation of labored breathing, honking cough, and bilateral epistaxis that were caused by pneumonia and collapsed trachea. A transtracheal aspiration revealed highly cellular, serosanguineous fluid. Radiography revealed a patchy alveolar pattern and a narrowed tracheal lumen. Endoscopy confirmed narrowing of the tracheal lumen. Streptococcus zooepidemicus was isolated on culture of the transtracheal aspirate. The horse responded to penicillin treatment, and the tracheal collapse improved endoscopically after 4 days, with complete recover...
Bristol DG.Caudally based axial pattern and random pattern skin flaps, 5 cm x 10 cm, were raised on the abdomens of seven foals. Blood flow was measured 7.5 cm from the flap bases during incremental increases in applied tension. At tensions less than 1400 g, cutaneous blood flow was more than four times higher in axial pattern flaps than in random pattern flaps. Blood flow in axial pattern flaps at tensions up to 1500 g was greater than baseline flow in random pattern flaps. After removal of applied tension, perfusion in axial pattern flaps gradually increased but remained below baseline values. A short ...
Foster AP, Cunningham FM, Lees P.Intradermal administration of PAF (0.001-1 micrograms/site), but not lyso-PAF (10 micrograms/site), in the horse caused an increase in cutaneous vascular permeability which was maximal by 32 min. Responses to PAF and histamine were reduced by coadministration of the histamine 1 receptor antagonist chlorpheniramine, although only the inhibition of histamine-induced responses was dose-related and statistically significant. The cyclo-oxygenase inhibitor indomethacin was without effect on PAF-induced increases in vascular permeability. These findings suggest that the actions of PAF on equine skin ...
Slocombe RF, Huntington PJ, Friend SC, Jeffcott LB, Luff AR, Finkelstein DK.Nine horses with clinical signs of Australian Stringhalt were killed and tissues collected for a detailed pathological study. Lesions were limited to peripheral nerves and muscles. The most severely affected nerves were the superficial and deep peroneal, distal tibial, plantar digital, volar and recurrent laryngeal nerve with changes characterised by a selective loss of large diameter myelinated fibres with various degrees of demyelination, fibrosis, Schwann cell proliferation and onion-bulb formation. A routine evaluation of the brain and spinal cord by light microscopy failed to reveal any c...
al-Massad FK, Kadir FH, Moore GR.The origin of the 440 nm fluorescence of horse spleen ferritin and of Pseudomonas aeruginosa and Azotobacter vinelandii bacterioferritin has been investigated using a Nitro Blue Tetrazolium/glycinate colorimetric test specific for quiones [Paz, Flückiger, Boak, Kagan & Gallop (1991) J. Biol. Chem. 266, 689-692]. The results of the analysis indicate that ferritin and bacterioferritins contain quinones. A possible functional role of these quinones in iron uptake and release is described, as is the possibility that the presence of quinones in these proteins results from oxidative damage.
Jaeschke G, Rudolph R.Clinicopathological aspects of equine leukosis are discussed in a review. Among various other findings, only hypercalcaemia accompanied by paraneoplastic syndrome in the course of equine leukosis, increased values of alkaline phosphatase as usual in tumorous diseases, and hypalbuminaemia and hypergammaglobulinaemia in mesentric and intestinal forms of equine leukosis seem to have some diagnostic and pathogenetic significance. Changed values of further parameters are more or less non-specific concomitant signs, indicating that other organs or organ systems have been affected. However, in case o...
Stick JA, Arden WA, Robinson RA, Shobe EM, Roth RA.Effects of 1 hour of colonic volvulus and 3 hours of reperfusion on concentrations of thromboxane (TXB2) and prostacyclin (6-keto-PGF1 alpha) in portal, pulmonary arterial, and jugular blood were determined by radioimmunoassay to assess the site of production and clearance of these eicosanoids from the circulation in 5 anesthetized ponies. Colonic volvulus had no significant effect on mean arterial pressure or TXB2 concentrations, but significantly (P less than 0.05) increased 6-keto-PGF1 alpha concentrations in all blood samples. Immediately after colonic reperfusion, all eicosanoid concentra...
Templeton CB, Bottoms GD, Fessler JF, Turek JJ, Boon GD.The objectives of this study were to determine the pathophysiological effects of increasing amounts of endotoxin administered intraperitoneally (IP) for 24 hr at which time an intravenous (IV) injection of endotoxin was given. The ability of flunixin meglumine (FM), a nonsteroidal antiinflammatory drug with antiprostaglandin activity, to provide protective effects was also determined. Eight ponies were divided into two groups of four ponies each; one group (untreated) received endotoxin only and the other group (treated) received endotoxin while being treated with flunixin. Hemodynamic and ser...
Milne EM, Pemberton AD, McGorum BC, Dixon PM, Scudamore CL, Miller HR.The concentration of alpha-1 proteinase inhibitor (API) was measured in the pulmonary epithelial lining fluid (PELF) of horses with chronic obstructive pulmonary disease (COPD) while they had clinical signs and while they had none. The concentrations of total protein, albumin and API were significantly higher in the PELF of animals with clinical signs of COPD. The correlation between albumin and API in the PELF suggested that most of the API was derived from the serum.
Stokes SM, Bertin FR, Stefanovski D, Poulsen L, Belknap JK, Medina-Torres CE, Pollitt CC, van Eps AW.Continuous digital hypothermia (CDH) prevents lamellar failure in the euglycaemic hyperinsulinaemic clamp (EHC) and oligofructose (OF) laminitis models, but the mechanisms remain unclear. Objective: To evaluate the effects of CDH on lamellar energy metabolism and perfusion in healthy horses and during EHC and OF laminitis models. Methods: In vivo experiment. Methods: Archived samples 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, a...
von Fellenberg R.The importance of proteases and protease inhibitors for the pathogenesis of pulmonary emphysema and chronic bronchitis of the horse is described. Endogenous elastases from neutrophil granulocytes and macrophages, which probably provoke emphysema in the human being, are not relevant in horse emphysema. Exogenous elastases from different species of streptomyces may be responsible for emphysema generation in this species. Part of the exogenous elastases are poorly or not inhibited at all by the equine blood protease inhibitors especially by alpha 1-protease inhibitors. A disorder similar to genet...
Grosenbaugh DA, Hood DM, Amoss MS, Williams JD.Epidermal growth factor (EGF) receptors were detected in plasma membrane preparations of equine hoof wall laminar tissue at concentrations comparable to that of equine liver. Scatchard analysis of the equilibrium binding data suggested the presence of two classes of EGF binding sites in most of the controls (plasma membranes from clinically normal horses); a high-affinity class and a more numerous low-affinity class. The dissociation constant of the low-affinity class of EGF-specific receptors (KD = 1 x 10(-9)M) is in reasonable agreement with other values established for the EGF receptor. The...
Gerhards H.Antithrombin III (AT III) determinations were done in healthy and sick horses using the chromogenic substrate Chromozym TH. Reference values for adult horses at 25 degrees C were 18-25 IU AT III per ml plasma and 84-118% AT III activity of normal horse plasma, respectively. Precision and accuracy were good (intra assay coefficient of variation less than 2%, accuracy 10%). Surgical operations on healthy horses led to a biphasic decrease in AT III activity touching the lower border of the reference values on the second postoperative day. Other reasons for acquired AT III deficiencies included di...
Dixon JB, Allan D, West CR.The purpose of these investigations was to assemble and compare data which might illustrate a functional relationship between phytohaemagglutinin-induced transformation of equine lymphocytes in vitro and the haematological profiles of the lymphocyte donors. Statistically significant correlation between transformation and a haematological parameter was taken as evidence that both may be part of a common regulatory system. There was no evidence that transformation in vitro was affected by artefactual variation in the cellular composition of the cultures. Transformational behaviour of lymphocytes...
Blaze CA, Robinson NE.Apneic oxygenation was studied in six ponies for 30 minutes, and six horses for 10 minutes. Arterial blood was sampled at regular intervals for measurement of oxygen and carbon dioxide tensions (PaO2 and PaCO2) and calculation of alveolar-arterial oxygen tension difference (PAO2-PaO2). In both groups of animals, PaO2 decreased rapidly during the first 3 minutes of apnea, then more slowly. Although the mean value was above 100 mmHg at 10 minutes, there was considerable inter-animal variability. Before apnea, PAO2-PaO2 was slightly, but not significantly, larger in horses than in ponies and incr...
de la Calle J, Burba DJ, Ramaswamy CM, Hosgood G, Williams J, LeBlanc C, Moore RM.To compare plasma and synovial fluid endothelin-1 (ET-1) and nitric oxide (NO) concentrations in clinically normal horses and horses with joint disease. Methods: 36 horses with joint disease, and 15 horses without joint disease. Methods: Horses with joint disease were assigned to 1 of the 3 groups (ie, synovitis, degenerative joint disease [DJD], or joint sepsis groups) on the basis of findings on clinical and radiographic examination and synovial fluid analysis. Endothelin-1 and NO concentrations were measured in plasma from blood samples, collected from the jugular vein and ipsilateral cepha...
Smith JE, Agar NS.Anaemic horses do not provide reticulocytes during an erythropietic response. Acute blood loss was studied in 4 ponies as a model to monitor changes in erythrocyte metabolism during active erythropoiesis. Following phlebotomy, erythrocyte adenosine-5-triphosphate, adenosine-5-diphosphate, glucose-6-phosphate, fructose-6-phosphate, and phosphoenolpyruvate increased signifcantly. The remaining glycolytic intermediates did not change. It is suggested that the determination of erythrocyte adenosine-5-triphosphate may be used to evaluate erythrocyte response following acute blood loss in the horse....
Lavagnino M, Madison J, Williams MR, Arnoczky SP.To determine if regional variations in strain patterns occur within the suspensory ligament under tensile load. Local increases in strain may put certain regions of the suspensory ligament at risk and may explain the poor healing and high recurrence rates associated with suspensory branch injuries. Methods: The suspensory ligament and its bone attachments were isolated from each of 10 adult equine cadaveric forelimbs and radiodense reference beads were inserted throughout the length of the ligament. Specimens were attached to a custom fixture secured to a materials testing system. Radiographs ...
McGorum BC, Dixon PM.Horses with asymptomatic or symptomatic chronic obstructive pulmonary disease (COPD) and control horses were challenged with oil seed rape either by exposure to a field of flowering Brassica campestris for six days, or by an inhalation challenge with freshly collected pollen from Brassica napus, or by inhalation challenge with a commercial extract of B napus pollen. Clinical and bronchoscopic examinations showed that the challenges did not induce detectable pulmonary disease in the control or asymptomatic COPD affected horses and did not significantly affect their pulmonary mechanics, arterial...
Valberg SJ.Horses are particularly susceptible to developing exertional rhabdomyolysis (ER) characterized by muscle stiffness, pain, and reluctance to move. Diagnosis requires establishing abnormal increases in serum creatine kinase activity when horses exhibit clinical signs. The 2 main categories of ER include sporadic ER arising from extrinsic causes and chronic ER that arises from intrinsic continuous or episodic abnormalities in muscle function. This article focuses on treatment of acute ER and causes and management of sporadic ER. Differential diagnoses for chronic ER as well as the pathophysiology...
Art T, Kirschvink N, Smith N, Votion D, Lekeux P.The effect of a COPD crisis on arterial blood gases, heart rate, lactate and indices of oxidative stress were investigated before, during and 1 h after a 'run up to fatigue' in 6 COPD horses. They were investigated twice, randomly: once in acute crisis (C) and once in clinical remission (R). Arterial and mixed venous blood samples were collected and analysed for partial pressures in O2 and CO2. The mixed venous blood was also analysed for plasma lactate (LA) and packed cell volume (PCV), as well as for indices of oxidative stress, i.e. reduced glutathione, glutathione disulphide, glutathione r...
Tessier GJ, Traynor TR, Kannan MS, O'Grady SM.When the equine tracheal epithelium is mounted in Ussing chambers and bathed in plasma-like Ringer solution, the tissue generates a lumen-negative transepithelial potential (PD) of 22 mV and a short-circuit current (Isc) of 70-200 microA/cm2. Mucosal addition of 10 microM histamine produces a transient increase in the Isc followed by a return to baseline or below. Mucosal addition of 2 microM diphenhydramine inhibits the Isc response to mucosal histamine, whereas 100 microM mucosal cimetidine produces no effect. The average initial increases in Isc over time for mucosal vs. serosal histamine a...
Viel L.Equine allergic small airway disease is a highly prevalent respiratory condition among the stabled horse population. With the assistance of new diagnostic tools such as bronchoalveolar lavage, the condition can be recognized in young performing horses. The pathophysiological and clinical features resemble an earlier stage of chronic obstructive pulmonary disease as determined by the appearance of specific inflammatory cells. Although environmental management is paramount in controlling the disease, proper selective therapeutic regimens are as important to reduce the concurrent inflammation and...
Merlin A, Ravinet N, Sévin C, Bernez-Romand M, Petry S, Delerue M, Briot L, Chauvin A, Tapprest J, Hébert L.Cyathostomins are considered as the most prevalent and pathogenic parasites of grazing horses. The development on pastures of the free-living stages of these gastrointestinal worms is particularly influenced by outdoor temperature. Understanding the bionomics of free-living stages is an important prerequisite to implement mathematical models designed to assess the parasitic risk for grazing equids. The aim of this study was to assess the effect of 3 constant temperatures under laboratory conditions (10 ± 1 °C, 23 ± 2 °C, 30 ± 2 °C) and one fluctuating temperature under outdoor c...
Herholz C, Phillip M, Straub R, Ueltschi G, Busato A.The elimination of carbon dioxide from the lung can be used to monitor ventilation and perfusion, and 99mtechnetium-diethylenetriaminepentaacetate (99mTc-DTPA) clearance is a highly sensitive index of alveolar epithelial integrity, which is a presupposition for effective gas exchange. The aim of this study was to determine whether a correlation exists between indices of lung function derived from the single breath diagram for CO2, and 99mTc-DTPA clearance in horses with chronic obstructive pulmonary disease. The rate of 99mTc-DTPA elimination was negatively and substantially correlated with th...
Zamora CS, Vitums A, Nyrop KA, Sande RD.The heart of a 6-week old Arabian filly with a history of poor health and exercise intolerance revealed at postmortem examination, multiple cardiac malformations which included atresia of the right atrioventricular orifice (tricuspid atresia, with associated atrial and ventricular septal defects), complete transposition of the great arteries, anomalous drainage of the venae cavae and coronary sinus into the left atrium, coarctation of the aorta, and a small but patent ductus arteriosus. The course of blood through the heart was suggested and discussed.
Pliszczak-Król A, Gemra M, Kozdrowski R, Zalewski D, Iwaszko A.Recurrent Airway Obstruction (RAO), also called severe asthma or heaves, is a chronic disease in adult horses caused by aeroallergens from straw or hay. Disturbances in hemostasis (intensified coagulation and depressed fibrinolysis) are considered one of the prominent reasons of inflammatory process, injury and dysfunction of the lungs. The aim of the study was to evaluate chosen parameters of hemostasis in horses with active form of RAO. Ten RAO-horses (group R) and ten healthy horses (group C) were exposed to straw and hay allergen challenge. The prothrombin time (PT), activated partial thro...
Donaldson LL.In the United States, more than 75% of equine athletes are reported to suffer from exercise-related haemorrhage of the respiratory tract (Voynick and Sweeney, 1986; Sweeney et al., 1990). Fiberoptic endoscopy has traced the source of blood to beyond the bifurcation of the trachea. In 1981, the term exercise-induced pulmonary haemorrhage (EIPH) was introduced (Pascoe et al., 1981). Racehorses of all breeds, polo ponies and three-day event horses of mixed heritage, even foxhunters, may 'bleed' (Voynick and Sweeney, 1986; Pascoe et al., 1981; Sweeney and Soma, 1983; Hillidge, 1986). Any horse wor...
Divers TJ, George LW, George JW.Signs of acute hemolytic anemia developed in 4 adult horses from 2 Georgia farms 3 to 4 days after the ingestion of wilted leaves from cut red maple trees (Acer rubrum). Clinical findings included weakness, polypnea, tachycardia, depression, icterus, cyanosis, and brownish discoloration of the blood and urine. Blood changes included methemoglobinemia, free plasma hemoglobin, decreased pcv, and Heinz bodies in erythrocytes. These findings plus hemoglobinuria suggested intravascular hemolysis. Three of the 4 horses diet 5 to 7 days after ingestion of the leaves. Gross pathologic changes included...
Trout DR, Hornof WJ, Linford RL, O'Brien TR.Scintigraphy was used to evaluate digital circulation at 24 h intervals in 11 control horses and in nine horses affected with acute laminitis created by administration of a high-starch ration. Following intra-arterial injection of technetium-99m macroaggregated albumin into the brachiocephalic trunk, static images were acquired of the right front foot. Dynamic radionuclide angiograms and static blood pool images were also obtained after jugular vein injection of technetium-99m diethylenetriamine pentaacetic acid. These procedures were performed on standing horses, using either minimal or no tr...
Zerpa H, Vega F, Vasquez J, Ascanio E, Campos G, Sogbe E, Romero E, Ascanio M, García H.Endotoxaemia is a syndrome linked to the development of equine laminitis; however, the relationship between them is uncertain. The aim of this experiment was to evaluate the effect of an experimental acute sublethal endotoxaemia model on in vitro equine palmar digital vascular reactivity. Rings of arteries and veins of each forelimb were obtained from 11 clinically healthy horses submitted to two surgical procedures, 3 weeks apart. Before the second surgery, 0.25 microg/kg of lipopolysaccharide from Escherichia coli O55:B5 in saline, was administered i.v. in 30 min. After 3 h, the vessels were...
Crişan MI, Damian A, Gal A, Miclăuş V, Cernea CL, Denoix JM.The purpose of this study was to provide a detailed description of the vascular changes in the distal part of deep digital flexor tendon (DDFT). Eight isolated forelimbs were collected from 8 horses with DDF tendinopathy diagnosed post-mortem by ultrasound and gross anatomopathological examination. The samples were fixed in 10% neutral buffered formalin, softened in 4% phenol and dehydrated with ethylic alcohol. Goldner's Trichrome staining method was used. The histopathological examination revealed vascular proliferation associated with structural disorders of blood vessels. Angiogenesis, fib...
O'Sullivan S, McGowan CM, Junnila J, Hyytiäinen HK.Impinging dorsal spinous processes (IDSP) are typically diagnosed and graded using radiography, during which the effect of the horses' thoracolumbar posture on the interspinous spaces is not commonly considered. Posture can be altered from a spontaneous, relatively extended, or lordotic, position by manual facilitation of thoracic flexion ('thoracic lift'). This study aimed to ascertain if the thoracic vertebral interspinous space distances were increased by using facilitated thoracic flexion to alter the posture in horses diagnosed with IDSP. Seven horses of mixed breed and sex, median age 9....
Geiser DR, Walker RD.The pathophysiology and histopathology of thermal burns in large animals is very similar to that in humans. Burns are classified as first degree, superficial and deep second degree, third degree, and fourth degree, depending upon the depth of thermal injury. Most severe burns will produce a local and a systemic response--both of which must be properly treated to increase the patient's chances for survival. The systemic response is mainly characterized by hypovolemia, fluid and electrolyte loss, protein loss, pulmonary edema, increased caloric requirements, and depressed immune responses. The l...
Bentley AP, Barton MH, Lee MD, Norton NA, Moore JN.To determine which antimicrobials that are used to treat neonatal foals with septicemia attributable to Escherichia coli will minimize endotoxin release from bacteria and subsequent activity of inflammatory mediators while maintaining bactericidal efficacy. Methods: Blood samples from 10 healthy foals. Methods: Escherichia coli isolates A and B were isolated from 2 septicemic foals, and minimal inhibitory concentrations (MIC) were determined for 9 antimicrobials. Five of these antimicrobials were tested in vitro at 2 and 20 times their respective MIC. Whole blood or mononuclear cells grown in ...
Cambridge H, Reynoldson JA, Dunsmore JD.Plasma thromboxane B2 (TXB2) the stable inactive metabolite of thromboxane A2 (TXA2), was measured daily by specific radioimmunoassay in three groups of animals before and after experimental infection with Strongylus vulgaris. Infection of four 'parasite naive' foals produced a typical acute syndrome with intermittent but statistically insignificant rises in TXB2 levels. Interpretation of results was complicated by the presence of a non-septic peritonitis associated with implantation of the foals with electrodes for recording myoelectrical activity. In two foals of similar age, with some natur...
Krunajević T, Bergsten G.The clinical and pathological details of a case of ataxia in a 3-month-old colt are described. A marked protrusion into the vertebral canal of the body of the 3rd cervical vertebra was observed. C and C were immovably joined so that the deformity could not be corrected by extension of the spinal column at this point. There was a compression of the spinal cord corresponding to the protrusion. The cause of this luxation could not be established. It may be assumed that the distortion was congenital, or caused by trauma at an early stage and that clinical symptoms could be observed only when, a ma...
