The spleen in horses is an organ located in the abdominal cavity, playing a significant role in the circulatory and immune systems. It is involved in the storage and filtration of blood, as well as the production and recycling of red blood cells. The spleen also contributes to the immune response by producing lymphocytes and storing monocytes. In equine physiology, the spleen is known for its ability to contract and release a large reservoir of red blood cells into circulation, particularly during physical exertion, enhancing oxygen delivery to tissues. This page compiles peer-reviewed research studies and scholarly articles that explore the anatomy, function, and clinical relevance of the spleen in equine health.
Geelen SN, Bernadina WE, Grinwis GC, Kalsbeek HC.A 15-year-old Dutch warmblood mare was presented because of lethargy, which had been present for several weeks, and severe anaemia. Total protein was high and serum electrophoresis revealed a monoclonal peak in the alpha-2 region. Monoclonal immunoglobulin, IgG(T), was detected by immuno-electrophoresis in serum and urine. Postmortem examination revealed a relatively large number of plasmacytoid cells in the bone marrow and a monotonous population of plasmacytoid cells in the spleen. These findings are suggestive of a plasma cell myeloma.
Wood SC, Fedde MR.Splenic contraction in racing horses increases the hematocrit (hct), thereby increasing blood viscosity. We tested as to whether racing also affects the elastic properties of blood. Mares and geldings were studied for thus purpose. After racing, there was: (i) an increased erythrocyte count independent of gender and race distance (0.32 to 1.7 km): (ii) an increased mean erythrocyte volume in both sexes; (iii) an increased heterogeneity of RBC size in both sexes; (iv) an increased plasma fibrinogen concentration and erythrocyte sedimentation rate in both sexes; and (v) an increased elastic yiel...
Geelen SN, Sloet van Oldruitenborgh-Oosterbaan MM.A splenic hemangiosarcoma with multiple organ metastases in a pony is reported. Clinical signs included weakness and pallor. Abdominal paracentesis revealed haemorrhagic fluid. Laboratory data included anaemia, thrombocytopenia and hypoproteinaemia. Necropsy findings included a haemangiosarcoma in the spleen with metastases in the lung, liver, kidney and omentum.
Yang X, Chasteen ND.Electron paramagnetic resonance spectroscopy and gel permeation chromatography were employed to study the molecular diffusion of a number of small nitroxide spin probes (approximately 7-9 A diameter) into the central cavity of the iron-storage protein ferritin. Charge and polarity of these radicals play a critical role in the diffusion process. The negatively charged radical 4-carboxy-2,2,6,6-tetramethylpiperidine-N-oxyl (4-carboxy-TEMPO) does not penetrate the cavity whereas the positively charged 4-amino-TEMPO and 3-(aminomethyl)-proxyl radical and polar 4-hydroxy-TEMPO radical do. Unlike th...
Persson SG, Funkquist P, Nyman G.The purposes of this study were to elucidate the influences of age and sex on the mass specific blood volume parameters: total blood volume (TBV/BW, ml/kg), plasma volume (PV/ BW, ml/kg), total red cell volume (CV/BW, ml/kg) and maximal packed cell volume (PCV, l/l, i.e. after total mobilisation of the splenic red cell reservoir) and to establish reference values for these in normally performing Standardbred trotting race horses. In total 205 horses were studied. They were all, according to their owners and/or trainers, performing satisfactorily in racing or training for shortly impending raci...
Leo M, Kolb E, Siebert P, Dittrich H.The activity of adenosine deaminase in the cerebrum, cerebellum, brain stem, heart, skeletal muscle, lung, liver, spleen, kidney and testes of horses of the breeds Haflinger and Thüringer Kaltblut was not different from each other. In the erythrocytes and the plasma no activity of the ADA exists.
Pead S, Durrant E, Webb B, Larsen C, Heaton D, Johnson J, Watt GD.The binding of Cd2+, Zn2+, Cu2+, Ni2+, Co2+, Mn2+, and Mg2+ to apo, holo, reconstituted horse spleen ferritin (HoSF), and native holo HoSF with phosphate removed was measured by gel-exclusion chromatography. Three classes of strong binding interactions (Kd < 10(-7) M) with apo HoSF at pH 7.5 were found for the various M2+ studied: high stoichiometric binding (30-54 M2+/HoSF) for Cd2+, Zn2+, Cu2+, with two protons released per metal bound; intermediate binding (16 M2+/HoSF) for Ni2+ and Co2+, with one proton released per metal bound; and low levels of binding (2-12 M2+/HoSF) for Mn2+, Mg2+, and...
Galuppo LD, Snyder JR, Pascoe JR.Laparoscopy was performed on 6 horses (2 mares, 2 geldings, 2 stallions) to determine the normal laparoscopic anatomy of the equine abdomen. After withholding feed for 36 hours, horses were examined from the left and right paralumbar fossae, and the visceral anatomic structures were recorded by videotape and photography. One mare developed emphysema located subcutaneously at the primary laparoscopic portal; otherwise, there were no complications. The anatomic structures of diagnostic importance that were observed in the left half of the abdomen were the hepatic duct; left lateral and quadrate ...
Barnard BJ, Bengis R, Keet D, Dekker EH.The viraemic period of African horsesickness is significantly longer in experimentally infected zebra than in horses. The virus could be isolated 40 d post-infection from blood and 48 d post-infection from spleen. The introduction of zebra into African horsesickness-free countries should therefore be considered carefully, and preferably be restricted to serologically negative zebra.
Brown CC, Meyer RF, Grubman MJ.In a retrospective study, a negative-sense digoxigenin-labeled RNA probe, corresponding to the gene encoding nonstructural protein-1 of African horse sickness virus (AHSV) serotype 4, was applied to formalin-fixed, paraffin-embedded tissue taken from horses in the terminal stages of infection with AHSV. Fifteen infected ponies and one noninfected control were studied. Ponies exhibited a range of clinical signs and lesions. Thirteen ponies were infected with serotype 4, one with serotype 1, and one with serotype 2. Ponies were monitored clinically and euthanatized when severely clinically ill. ...
Hardy J, Bednarski RM, Biller DS.Pharmacologically induced splenic contraction might be useful during certain medical or surgical procedures in horses. The effects of phenylephrine, an alpha 1-adrenergic receptor agonist, on hemodynamic function and splenic dimensions were examined in 6 healthy adult horses. Phenylephrine infusion (1, 3, or 6 micrograms/kg of body weight/min for 15 minutes) resulted in a dose-related increase in mean pulmonary artery pressure; right atrial pressure; systolic, mean, and diastolic arterial pressures; and packed cell volume (P = 0.0001). Concurrent decreases in heart rate and specific cardiac ou...
Kim DY, Hodgin EC, Lopez MK, Nasarre C.A large primary retroperitoneal sublumbar neoplasm in a horse, with disseminated neoplastic foci in the brain, lung, kidney and spleen is described. The diagnosis was based on light microscopical studies and positive immunostaining for neuron-specific enolase. Because of the location of the primary tumour mass, the aortico-sympathetic ganglion (organ of Zukerkandl) is proposed as the origin.
Knowles DP, Kappmeyer LS, Perryman LE.Horses possessing a normal immune system and spleen often control infection caused by Babesia equi. However, splenectomized horses are unable to control B. equi infection and usually succumb to the infection. To investigate the role of the spleen in the control of B. equi infection in the absence of specific immune responses, two 1-month-old foals with severe combined immunodeficiency (SCID) and two age-matched normal foals were inoculated with B. equi. The SCID foals became febrile seven days postinoculation and developed terminal parasitemias of 41 and 29%. The SCID foals had greater than 50...
Orino K, Yamamoto S, Watanabe K.Lower apparent concentrations of ferritin were observed in horse plasma than in serum using the enzyme-linked immunosorbent assay (ELISA). However, the ferritin concentrations in plasma and serum were increased to the same level on heating the samples at 75 degrees C for 15 min. These results suggest that horse plasma has specific ferritin-binding protein(s) which inhibit(s) the ferritin assay. The apparent ferritin concentrations in horse serum were markedly decreased by adding horse fibrinogen to the serum. It was also found that fibrinogen bound to spleen ferritin and inhibited the immunoas...
Strange R, Morante S, Stefanini S, Chiancone E, Desideri A.Extended X-ray absorbance fine structure measurements have been carried out on the initial Fe(III)-apoferritin complex at a Fe/subunit ratio of 2 in native and modified horse spleen apoferritin. Analysis of the data indicates that in the native protein the iron forms a protein-bound polynuclear cluster (Fe-Fe distance 3.4 A) with a first coordination sphere constituted by 5-6 low-Z atoms, e.g., nitrogen atoms, carboxylate-like ligands or oxo bridges between the iron atoms. Modification of Cys-126, a residue localized on the outer surface of the hydrophilic three-fold channels, with p-chloromer...
McKeever KH, Hinchcliff KW, Reed SM, Hamlin RL.Six intact (IN) and five splenectomized (SP) mares were subjected to an incremental exercise test to examine the effects of splenectomy on blood pressure responses during exercise. During the test the horses ran up a 6 degree grade on a treadmill set at an initial speed of 4 m/s. Speed was increased 1 m/s every 1 min until heart rate (HR) reached a plateau. Hemodynamic data were collected continuously and analyzed for the last 18 s of the 4, 5, 6, and 7 m/s steps of the exercise test. There were no differences (P > 0.05) between the groups for resting means for any parameter measured in the...
McKeever KH, Hinchcliff KW, Reed SM, Robertson JT.Six intact and 6 splenectomised mares were given an incremental exercise test on a treadmill to examine the fluid and electrolyte changes associated with exercise and the role of the spleen in these changes. Blood samples were obtained at rest and at the end of each 1-min step of the test. Exercise at 7 m/sec caused significant (P 0.05) in either group (intact = 2.7%; splenectomised, = 3.5%). This appears to be the first record of substantial changes of these constituents during short-term exercise, even before the onset of visible sweat losses. The changes in the concentration of plasma prot...
Trostle SS, Markel MD.Incarceration of the large colon through a rent in the gastrosplenic ligament of a horse was surgically corrected via ventral midline celiotomy. Clinical signs were similar to those in other horses with nonstrangulating large colon disorders. Diagnosis of large colon incarceration in the gastrosplenic ligament was determined by surgical abdominal exploration. The findings of medial deviation of the spleen, location of the large colon lateral to the stomach and caudolateral to the spleen, and caudocraniad passage of the large colon through the gastrosplenic ligament are similar to findings in h...
Aminlari M, Vaseghi T.1. A new colorimetric method was used for determination of arginase in different tissues of some domestic animals. 2. In all species studied liver was the richest source of arginase. 3. Significant differences were observed in the specific activity of arginase in livers from different species. 4. In all species, besides liver, kidney and brain also contained significant levels of arginase. 5. In the dog, in addition to the three organs mentioned above, lung, heart, spleen and skeletal muscle showed some arginase activity. 6. In sheep and cattle significant arginase activity was observed in the...
Chaffin MK, Schmitz DG, Brumbaugh GW, Hall DG.Splenic and hepatic ultrasonography were beneficial for diagnosis of lymphosarcoma in 3 horses with anorexia, weight loss, and lethargy. Ultrasonographic abnormalities of the spleen included a large, complex, hypoechoic mass in 1 horse, multiple well-marginated, hypoechoic nodules in 1 horse, and diffuse hyperechogenicity in another horse. Ultrasonographic abnormalities of the liver included a spherical, hypoechoic nodule in 1 horse and diffuse hyperechogenicity in another. Histologic examination of ultrasound-guided biopsy specimens or aspirates revealed lymphosarcoma. Necropsy findings confi...
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.
Hinchcliff KW, McKeever KH, Muir WW.The effect of furosemide administration (1 mg/kg body weight, i.v.) on plasma and blood volumes in 6 intact and 4 splenectomized horses was measured using Evans blue dye dilution, hematocrit, and hemoglobin and plasma total solids concentrations. Body weight decreased by 33.6 +/- 3.3 and 33.7 +/- 0.8 g/kg 4 h after furosemide administration to intact and splenectomized mares, respectively. Plasma volume, estimated by Evans blue dye dilution, was reduced by 8.3 +/- 3.3% (mean +/- SE) 4 h after furosemide administration. The reduction in plasma volume was first detectable 5-10 min after furosemi...
Kadir FH, al-Massad FK, Fatemi SJ, Singh HK, Wilson MT, Moore GR.Reactions of reduced horse spleen ferritin with horse and Saccharomyces cerevisiae ferricytochromes c, cow ferricytochrome b5, sperm-whale metmyoglobin and Pseudomonas aeruginosa ferricytochrome c-551 were investigated by u.v.-visible spectrophotometry. In all cases the reduced ferritin reduced the ferrihaemoproteins. The rate of reduction varied from less than 0.2 M-1.s-1 for metmyoglobin to 1.1 x 10(3) M-1.s-1 for horse ferricytochrome c (0.1 M-phosphate buffer, pH 7.4, at 25 degrees C). We conclude that the mechanism of ferrihaemoprotein reduction involves long-range electron transfer throu...
Ueda H, Abe M, Takehana K, Iwasa K, Hiraga T.The innervation of the red pulp in the spleen of horse and pig was investigated by electron microscopy. In addition, the neurilemma was studied by immunohistochemistry specific for S-100 protein. In the pig, a large population of smooth-muscle cells extending from the smooth-muscle trabeculae was present in the red pulp. The cytoplasmic processes of reticular cells enwrapped the smooth-muscle cells, and nerve fibres were distributed between the smooth-muscle cells and the reticular cells. The nerve terminals clustered toward the facing of the smooth-muscle cells. Nerve fibres and terminals wer...
Kadir FH, Moore GR.Horse spleen ferritin, a spherical protein shell of 24 subunits, contains no haem when extracted. This contrasts with ferritins isolated from bacterial sources which have the capacity to bind up to 24 haem groups [(1990) FEBS Lett. 271, 141-143] via two methionine residues [(1990) Nature 341, 771]. Here it is shown that horse spleen ferritin can bind between 15 and 17 haems per 24 subunits with an apparent association constant of 2.2-3.2 x 10(4) M-1. The strength of haem binding appears to be unaffected either by the presence of the core or by the oxidation state of the haem. The demonstration...
Snow DH, Martin V.To investigate the claim that equine erythrocytes released from the spleen are older cells than those found at rest in the circulation, the 2,3, diphosphoglycerate (2,3 DPG), adenosine triphosphate (ATP) and creatine concentration of erythrocytes before and following splenic emptying were examined. Normal values for thoroughbreds (43) and ponies (10) at rest were established. Following either exercise or intravenous injection of adrenaline in six thoroughbreds, there was an increase in erythrocyte creatine content and a decrease in ATP concentration. Exercise produced a slight increase in 2,3 ...
Mair TS, Yeo SP, Lucke VM.Two horses with deposits of lymphosarcoma, one in the spleen, the other in the mediastinum, several lymph nodes and kidneys, lost weight rapidly and became depressed and weak. They were hypercalcaemic and post mortem examination revealed extensive calcification of the heart and major vessels. There was no evidence of bone marrow metastases in the one horse whose marrow was examined, and the thyroid and parathyroid glands of both horses were grossly normal.
Rice NR, Lequarre AS, Casey JW, Lahn S, Stephens RM, Edwards J.The amount and distribution of viral DNA were established in a horse acutely infected with the Wyoming strain of equine infectious anemia virus (EIAV). The highest concentration of viral DNA were found in the liver, lymph nodes, bone marrow, and spleen. The kidney, choroid plexus, and peripheral blood leukocytes also contained viral DNA, but at a lower level. It is estimated that at day 16 postinoculation, almost all of the viral DNA was located in the tissues, with the liver alone containing about 90 times more EIAV DNA than the peripheral blood leukocytes did. Assuming a monocyte-macrophage ...
Strange R, Morante S, Stefanini S, Chiancone E, Desideri A.Extended X-ray absorbance fine structure measurements have been carried out on the initial Fe(III)-apoferritin complex at a Fe/subunit ratio of 2 in native and modified horse spleen apoferritin. Analysis of the data indicates that in the native protein the iron forms a protein-bound polynuclear cluster (Fe-Fe distance 3.4 A) with a first coordination sphere constituted by 5-6 low-Z atoms, e.g., nitrogen atoms, carboxylate-like ligands or oxo bridges between the iron atoms. Modification of Cys-126, a residue localized on the outer surface of the hydrophilic three-fold channels, with p-chloromer...
Brunel C, Cathala G.1. Alkaline phosphatases (orthophosphoric monoester phosphohydrolase, EC 3.1.3.1) from brain, kidney, liver, bone, lung and spleen, which are not very sensitive to l-phenylalanine, are strongly inhibited by imidazole, whereas the placental and intestinal enzymes, which are very sensitive to l-phenylalanine, are only slightly affected. This is a new possibility for distinguishing the alkaline phosphatase isoenzymes.
2. The inhibition is apparently of an uncompetitive type, suggesting that the inhibitor interacts with the ES complex to form an EIS complex.
3. Histidine acts upon all enzyme...
Semioshkina N, Voigt G, Fesenko S, Savinkov A, Mukusheva M.The radiological assessment of the impact of nuclear weapon's testing on the Semipalatinsk Test Site (STS) on the local population requires comprehensive site-specific information on radionuclide behaviour in the environment. However, information on radionuclide behaviour in the conditions of the STS is rather sparse and, in particular, there are no data in the literature on parameters of radionuclide transfer from feed to horse products proofed to be important contributors to the internal dose to the local population. The transfer of 137Cs and 90Sr to horse milk and meat was studied under lab...
Mair TS, Yeo SP, Lucke VM.Two horses with deposits of lymphosarcoma, one in the spleen, the other in the mediastinum, several lymph nodes and kidneys, lost weight rapidly and became depressed and weak. They were hypercalcaemic and post mortem examination revealed extensive calcification of the heart and major vessels. There was no evidence of bone marrow metastases in the one horse whose marrow was examined, and the thyroid and parathyroid glands of both horses were grossly normal.
Bila CG, Perreira CL, Gruys E.Horses on several farms in Mozambique were inadvertently fed with a concentrate containing 69 ppm monensin. The horses developed acute signs of toxicity and several died. The animals were depressed, anorectic and paretic before death. Epistaxis was observed in 1 case. Petechial haemorrhages were present in the muscles, heart, lungs, gastrointestinal tract and spleen in 3 horses necropsied. No significant histopathological cardiac and skeletal muscle lesions were seen, except in 1 case, in which there was focal loss of myofibrils.
Weaver BM, Staddon GE, Pearson MR.The blood content of tissue in eight anaesthetized sheep and three anaesthetized horses was measured using chromium labelled autologous red blood cells. 2. Approximately half the total blood volume was found to be distributed within the body tissues and, with the exception of the spleen and fat, the distribution was similar in these two species.
Roberts MC, Groenendyk S.Splenectomy was successfully performed on 2 aged horses to facilitate experimental studies of Babesia equi infection. Resection of part of the 17th rib provided the most acceptable approach and avoided many complications encountered on removing part of the 16th rib.
Kumanomido T, Kamada M, Wada R, Kenemaru T, Sugiura T, Akiyama Y.Sagiyama virus is a member of the Getah virus group. Its pathogenicity for horses was examined. All the horses infected with the original 4 strains of Sagiyama virus (M6/Mag 33, Mag 121, Mag 132 and Mag 258) developed pyrexia ranging from 39.0 to 40.0 degrees C. Other clinical signs, characterized by eruptions, edema in the hind legs, enlargement of the submandibular lymph node and mild leukopenia, were also manifested. Viremia occurred 1-4 days post-inoculation (p.i.). Virus was recovered from spleen, liver, lung and various lymph nodes of a horse autopsied on Day 4 p.i. The maximum titer of ...
Ringger NC, Edens L, Bain P, Raskin RE, Larock R.A 5-year-old Thoroughbred mare presented with a 4 week history of weight loss, fever and leukopenia. Rectally, a large active foetus, thickened spleen and an abdominal mass were palpated. Leukopenia, mild anaemia, marked thrombocytopenia and hyperfibrinogenaemia were found. Cytology and cytochemical staining of a bone marrow aspirate supported a diagnosis of acute myelogenous leukaemia. The mare deteriorated despite medical therapy and was humanely euthanased.
Kelton DR, Holbrook TC, Gilliam LL, Rizzi TE, Brosnahan MM, Confer AW.A 14-year-old spayed American Paint mare was evaluated for mild colic, anorexia, pyrexia, and pancytopenia. Physical examination revealed mild tachycardia, tachypnea, and pale mucous membranes. Serial laboratory analyses revealed progressive pancytopenia, hyperfibrinogenemia, and hyperglobulinemia. A few large atypical cells were observed in peripheral blood smears. Results of tests for equine infectious anemia and antipenicillin antibody were negative. Serum protein electrophoresis indicated a polyclonal gammopathy. Smears of bone marrow aspirates contained hypercellular particles, but cell l...
Markel MD, Dorr TE.Multiple myeloma was diagnosed in a 22-year-old Arabian mare with a history of chronic weight loss. Quantitative immunoglobulin analysis revealed monoclonal gammopathy (IgG(T), 9,800 mg/dl). Due to progressive weight loss, the horse was euthanatized. Microscopy of tissues revealed plasma cell infiltrates in bone marrow, spleen, pituitary gland, adrenal cortex, muscle of the tongue, and bronchial, renal, and mesenteric lymph nodes.
Davis JL, Manohar M.Large increases in systemic and pulmonary arterial pressures of exercising healthy ponies have been observed. Because exercise causes a considerable increase in PCV of ponies, we examined the effect of splenectomy on exercise-induced changes in systemic and pulmonary pressures. These pressures (taken with catheter-tip micromanometers) and indicator dilution cardiac output were determined on 9 healthy ponies that had undergone splenectomy 4 to 9 weeks before the study. Data obtained at rest and during submaximal (10.5 to 11.0 mph) and maximal (14 to 15 mph) exercise from these ponies were compa...
Aminlari M, Vaseghi T.1. A new colorimetric method was used for determination of arginase in different tissues of some domestic animals. 2. In all species studied liver was the richest source of arginase. 3. Significant differences were observed in the specific activity of arginase in livers from different species. 4. In all species, besides liver, kidney and brain also contained significant levels of arginase. 5. In the dog, in addition to the three organs mentioned above, lung, heart, spleen and skeletal muscle showed some arginase activity. 6. In sheep and cattle significant arginase activity was observed in the...
McKeever KH, Hinchcliff KW, Reed SM, Robertson JT.Six intact and 6 splenectomised mares were given an incremental exercise test on a treadmill to examine the fluid and electrolyte changes associated with exercise and the role of the spleen in these changes. Blood samples were obtained at rest and at the end of each 1-min step of the test. Exercise at 7 m/sec caused significant (P 0.05) in either group (intact = 2.7%; splenectomised, = 3.5%). This appears to be the first record of substantial changes of these constituents during short-term exercise, even before the onset of visible sweat losses. The changes in the concentration of plasma prot...
Manohar M.1. Transmural distribution of myocardial blood flow was studied using 15 micron diameter radionuclide-labelled microspheres in six normal ponies and nine splenectomized ponies at rest, and during maximal exercise performed without as well as with adenosine infusion (3 microM kg-1 min-1). The splenectomized ponies were also studied during submaximal exercise performed at 75% of the workload. 2. Maximal exertion in normal ponies increased heart rate (348%), mean arterial blood pressure (40.9%), rate-pressure product (563%), arterial O2 content (43.2%), and mean pulmonary artery pressure (247%). ...
Williams S, Cooper J, Freeman S.Ultrasonography is an important diagnostic tool in the investigation of abdominal disease in the horse. Several factors may affect the ability to image different structures within the abdomen. The aim of the study was to describe the repeatability of identification of abdominal structures in normal horses using a detailed ultrasonographic examination technique and using a focused, limited preparation technique. Methods: A detailed abdominal ultrasound examination was performed in five normal horses, repeated on five occasions (total of 25 examinations). The abdomen was divided into ten differe...
Tschetter JR, Davis WC, Perryman LE, McGuire TC.Eight murine monoclonal antibodies (mAb) were used to identify the equine CD8 alpha or CD8 beta chains and to define the expression of these chains on lymphocytes from various lymphoid tissues. CD8 alpha was a 39 kDa protein and CD8 beta was a 32 kDa protein. Both chains were expressed on most of the CD8+ T lymphocytes in the peripheral blood, spleen, thymus, mesenteric lymph nodes and ileal intraepithelial lymphocytes (IEL), however, in each lymphoid compartment a percentage of lymphocytes expressed only the CD8 alpha chain. The largest percentage of CD8 alpha alpha expressing T lymphocytes w...
Sears KP, Knowles DP, Fry LM.The global importance of the hemoparasite to equine health was recently shown by its resistance to imidocarb dipropionate (ID) and its interference with clearance by ID in some co-infected horses. Genetic characterization of revealed marked genomic reduction compared to , and initial experiments demonstrated reduced clinical severity in spleen-intact horses. Furthermore, in early experiments, splenectomized horses survived infection and progressed to an asymptomatic carrier state, in stark contrast to the high fatality rate of in splenectomized horses. Thus, we hypothesized that is less ...
Herbach N, Breuer W, Hermanns W.Post-mortem examination was performed on a horse that died after exhibiting signs of colic. Gross findings included haemoperitoneum and a large round encapsulated mass located in the sublumbar area cranial to the left kidney. On sectioning the mass was solid red to brown and small nodules of similar tissue were noted at the periphery of the mass. The spleen was firm and three nodules were found in one thyroid gland. Microscopically, the abdominal mass, adjacent nodules, the spleen and one thyroid nodule consisted of clusters and cords of round to oval neoplastic cells, separated by a fine coll...
McGuire TC, Banks KL, Davis WC.Combined immunodeficiency (CID) is a significant disease in terms of prevalence in Arabian foals and is a useful animal for study of a similar condition in children. Thymuses from all CID foals examined were extremely hypoplastic. Light and electron microscopic examination of thymuses from CID foals, as well as a thymus from an aborted CID fetus, demonstrate that the basic thymic structure is intact, despite a number of dissimilar morphologic appearances. From these data, we inferred that the thymic hypoplasia was caused by a failure of committed lymphocytes from the bone marrow to populate th...
Ueda H, Abe M, Takehana K, Iwasa K, Hiraga T.The innervation of the red pulp in the spleen of horse and pig was investigated by electron microscopy. In addition, the neurilemma was studied by immunohistochemistry specific for S-100 protein. In the pig, a large population of smooth-muscle cells extending from the smooth-muscle trabeculae was present in the red pulp. The cytoplasmic processes of reticular cells enwrapped the smooth-muscle cells, and nerve fibres were distributed between the smooth-muscle cells and the reticular cells. The nerve terminals clustered toward the facing of the smooth-muscle cells. Nerve fibres and terminals wer...
Mariën T, Adriaenssen A, Hoeck FV, Segers L.To report a technique for laparoscopic ablation of the renosplenic space in standing horses. Methods: Development of a technique to perform laparoscopic renosplenic space ablation in standing horses. Methods: Five healthy horses, aged 3 to 13 years, weighing 380 to 520 kg. Methods: Horses were restrained in standing stocks and sedated with detomidine (0.01 mg/kg intravenously [IV]) and butorphanol (0.01 mg/kg IV). Portal sites in the left paralumbar fossa were infiltrated with 2% mepivacaine. A laparoscopic portal was placed between the 17th and the 18th ribs. Two instrument portals were locat...
Facemire PR, Facemire LM, Honnold SP.A 2-year-old gelding presented with a history of lethargy and anorexia. Physical examination revealed pleural and abdominal fluid, as well as several masses in the scrotum. The horse became acutely dyspneic despite 7 days of supportive care. Because of the poor prognosis, the owners elected euthanasia. Gross necropsy findings included multiple masses in the scrotum and inguinal canals and along the dorsal peritoneal cavity. The neoplasm infiltrated the kidneys, liver, spleen, mesenteric lymph nodes, mesentery, and abdominal surface of the diaphragm. Histologically, the neoplasm is composed of ...
Fernandez C, Möller G.After a primary immune response to the alpha 1-6 epitope of dextran B512, dextran high responder strains exhibit a specific inability to produce IgM and IgG antibodies against this epitope, although they gave an expected secondary response to horse erythrocytes. Spleen cells from dextran-primed and-suppressed mice responded well to dextran after transfer to lethally irradiated previously untreated mice, indicating that tolerance or exhaustive proliferation of dextran reactive B cells is not responsible. Thymus-dependent dextran-protein conjugates also induced specific suppression. Suppression ...
Saulez MN, Burton A, Steyl JC, Williams JH, Clift SJ.The medical records of four horses whose intestines had been perforated by metallic wires were reviewed. Three of the horses developed acute colic, and the other progressively lost weight and became inappetent and pyrexic. Metallic wires were detected either by exploratory laparotomy or postmortem examination. In three of the horses there were adhesions containing an encapsulated metallic wire in the small intestine, and in the other the wire was contained within an abscess with multiple adhesions involving the liver, spleen and mesentery.
De Waal DT, Van Heerden J, Van den Berg SS, Stegmann GF, Potgieter FT.Both Babesia equi and Babesia caballi are endemic in large parts of South Africa. Attempts were made to obtain pure local isolates of both B. equi and B. caballi for the purpose of developing serological tests to study the epidemiology of equine babesiosis in this country. The indirect fluorescent antibody test was used to screen horses for B. equi and B. caballi in an endemic area. Seven horses and 3 donkeys between 3 and 36 months of age that tested negative were subsequently splenectomized. The splenectomy operation was performed through the abdominal approach. A 100% survival rate was achi...
