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Topic:Bone Marrow
Bone marrow in horses is a spongy tissue found within the cavities of certain bones, such as the pelvis, ribs, and femur. It is a vital component of the hematopoietic system, responsible for the production of blood cells, including red blood cells, white blood cells, and platelets. These cells are crucial for oxygen transport, immune function, and blood clotting, respectively. Bone marrow consists of two types: red marrow, which is actively involved in blood cell production, and yellow marrow, which primarily stores fat. The composition and activity of bone marrow can change with age, health status, and physiological demands. This page compiles peer-reviewed research studies and scholarly articles that explore the structure, function, and clinical implications of bone marrow in equine health and disease.
Morphologic study of repair of induced osteochondral defects of the distal portion of the radial carpal bone in horses by use of glued periosteal autografts [corrected]. The use of periosteal autografts to resurface osteochondral defects was investigated in 10 horses (2 to 3 years old), and the repair tissue was characterized morphologically. Middle carpal joint arthrotomies were made, and osteochondral defects were induced bilaterally on the distal articular surface of each radial carpal bone. Each defect measured approximately 1 cm2 and extended 3 mm into the subchondral bone plate. Residual subchondral bone plate of control and principal defects was perforated by drilling. A sterile fibrin adhesive was made by mixing a fibrinogen component and a thrombin co...
Studies of bone marrow and leucocyte counts in peripheral blood in fetal and newborn foals. Clinical and pathological records of 124 foals were studied. The foals were assigned to six groups; normal, premature, dysmature, bacterially infected, neonatal maladjustment syndrome and Equid herpesvirus type 1 (EHV-1) infected. Also, 6 pony fetuses were sampled via catheters in the umbilical vein and artery between 280 and 310 days gestation. Bone marrow aspiration was performed on a further 14 foals. Premature foals had significantly lower neutrophil counts than normal foals up to 5 h. Foals with bacterial infections had significantly lower neutrophil counts up to age 12 h. EHV-1 infected ...
[Spavin in horses]. The pathogenesis of bone spavin and its implications for diagnosis and therapy are reviewed. The pathogenesis of spavin can be divided into three phases, which are characterised by fibrillation of cartilage, osteolysis and ankylosis respectively. It will depend on the degree of osteolysis whether diagnostic anaesthesia should be added to standard clinical and radiological examinations. Satisfactory results of treatment in the group of patients with severe osteolysis can only be obtained by arthrodesis of the distal tarsal joints. It is expected that biomechanical investigations will provide a ...
[Bone marrow examination in the horse]. The technique of needle biopsy, the examination of aspirated bone marrow and the interpretation of bone marrow smears are described. The indications for a bone marrow biopsy are listed and the literature is reviewed. The significance of this examination is illustrated with some clinical cases.
Immunohistochemical localization of alpha 2-beta 1-glycoprotein in horses. Alpha 2-beta 1-glycoprotein may be found free in horse serum or complexed with alpha-1-proteinase inhibitor to form pre-alpha 2-elastase inhibitor. There has been little information published concerning alpha 2-beta 1-glycoprotein and its possible tissue sources in horses. A peroxidase-antiperoxidase technique was used to identify alpha 2-beta 1-glycoprotein in buffy coat and bone marrow neutrophils of healthy horses. Macrophages and neutrophils in bronchoalveolar lavage samples from clinically normal horses and from horses with chronic pulmonary disease also were positive for alpha 2-beta 1-g...
Surgical management of Rhodococcus equi metaphysitis in a foal. A chronic Rhodococcus equi metaphysitis involving the distal growth plate of the left third metatarsal bone had induced a longstanding lameness in a young foal. Abnormal hematologic values included mild anemia, hyperfibrinogemia, mild leukocytosis, and neutrophilia. Radiography of the distal portion of MT3 revealed a radiolucent zone on the medial aspect of the growth plate, and small pieces of bone suggestive of sequestra. Treatment with erythromycin estolate and rifampin, aggressive surgical debridement, and cancellous bone grafting helped resolve the bone infection.
Hypercalcaemia and soft tissue mineralisation associated with lymphosarcoma in two horses. 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.
Viral DNA in horses infected with equine infectious anemia virus. 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 ...
The influence of mineral supplementation on growth and skeletal development of yearling horses. Forty-six Thoroughbred and Quarter Horse yearlings were used in two experiments to evaluate the effect of mineral supplementation on growth and skeletal development. In the first experiment, concentrate and bermuda-grass hay diets providing 2.82 Mcal DE/kg (estimated), 13.0% CP, .62% Ca and .43% P on a DM basis were supplemented with trace minerals (TM) by adding 0, .5 or 1.0% TM premix to the concentrate. The TM content of the three diets (concentrate and hay) in mg/kg DM were: Fe 150, 162 and 176; Mn 56, 60 and 64; Zn 36, 53 and 69; and Cu 7, 8 and 11 for the low, medium and high TM levels, ...
Hemorrhagic diathesis caused by multiple myeloma in a three-month-old foal. Multiple myeloma was diagnosed in a 3-month-old Quarter Horse foal with chronic weight loss, chronic bronchopneumonia, and epistaxis. The foal had pancytopenia, thrombocytopenia, and monoclonal beta-globulinemia. Bone marrow aspirates contained between 80 and 90% plasma cells.
Biochemical indicators of bone formation in foals after transfer from pasture to stables for the winter months. Serum alkaline phosphatase activity and serum concentrations of osteocalcin, free thyroxine, protein, and cholesterol were measured in 14 foals monthly from birth to 1 year of age. A transient decrease (P less than 0.05) in alkaline phosphatase activity and osteocalcin, free thyroxine, and cholesterol concentrations was found in November after transferring the horses from pasture to stables for the winter months. During the 2 subsequent months, serum alkaline phosphatase activity and osteocalcin concentration increased slightly. Protein concentration was highest in late fall and decreased (P l...
Arthrodesis of the equine distal tarsal joints by perforated stainless steel cylinders. Perforated stainless steel cylinders filled with autogenous cancellous bone were implanted in the distal tarsal joints of four horses. Graft cell survival was poor two weeks after surgery in one horse. In two horses, at 10 months there was partial arthrodesis of the joints with incorporation of the implants into the osseous union. The implants were filled with vascularised woven bone. These two horses were sound nine months after surgery. One horse fractured its third tarsal bone and was still positive to a hock flexion test 12 months after surgery.
Effect of beta-tricalcium phosphate in surgically created subchondral bone defects in male horses. beta-Tricalcium phosphate (TCP) was evaluated as a synthetic bone grafting material in horses. Sixteen horses were randomly assigned to 4 groups of 4 horses. In each horse, an 11-mm by 10-mm circular defect with a smooth margin was created surgically in the weight-bearing surface of both third metacarpal bones (McIII) and the left third metatarsal bone. The defect in the left McIII was filled with TCP, the defect in the right McIII was filled with a mixture of 50% autogenous cancellous bone (ACB) and 50% TCP, and the defect in the left third metatarsal bone was not filled to serve as a control...
T lymphocyte development in horses. I. Characterization of monoclonal antibodies identifying three stages of T lymphocyte differentiation. Six monoclonal antibodies reacting with equine T lymphocytes at different stages of maturation were selected from antibodies produced against lymphoid cell preparations. EqT12 and EqT13 antibodies identified subsets of cortical thymocytes with high terminal deoxynucleotidyltransferase (TdT) activity and no phytolectin responsiveness. EqT12+ thymocytes were scattered throughout the cortex while EqT13+ thymocytes were located in the subcapsular cortex. EqT12 bound to small numbers of bone marrow cells, splenocytes, and circulating lymphoid cells, but not to mature T lymphocytes. EqT13 bound to v...
Pancytopenia caused by bone marrow aplasia in a horse. Pancytopenia was evaluated in a mature Quarter Horse gelding. A diagnosis of bone marrow aplasia was made on the basis of bone marrow hypocellularity. History of drugs administered included penicillin, oxytetracycline, trimethoprim-sulfadiazine, phenylbutazone, dipyrone, flunixin meglumine, and isoxsuprine. Clinical remission was observed after treatment with glucocorticoids, androgens, and broad-spectrum antimicrobials.
Immunologic reconstitution of foals with combined immunodeficiency. Thirty-eight foals with combined immunodeficiency (CID) received transplanted fetal liver cells, fetal liver and thymus cells, histocompatible bone marrow cells, or equine lymphocyte antigen (ELA) haploidentical bone marrow cells in an attempt to reconstitute their deficient immune systems. Engraftment was infrequent, partial, and unpredictable when fetal cells were employed. Three of five CID foals receiving ELA haploidentical bone marrow cells demonstrated partial reconstitution, but engraftment was only temporary. Administration of histocompatible bone marrow cells resulted in rapid, full a...
Use of an external skeletal fixation device and bone graft for arthrodesis of the metacarpophalangeal joint in horses. Arthrodesis of the metacarpophalangeal joint was attempted in 9 adult horses, using a new external skeletal fixation device and autogenous cancellous bone graft. Four horses had excellent results, 2 horses had fair results, arthrodesis failed in 2 horses, and 1 horse fractured the third metacarpal bone. The advantages of the technique included minimal surgical trauma to the area of injury, immediate rigid fixation of the metacarpophalangeal joint, and access for treatment of soft-tissue lesions at the site of injury. Although pin loosening and pin-track infection were complications when the de...
Growth and calcium metabolism in horses fed varying levels of protein. The effect of level of protein intake on growth and calcium metabolism was studied in 24 foals. Starting at four months old, the foals were fed one of three diets containing all nutrients, with the exception of protein, at levels recommended by the United States National Research Council Subcommittee on Horse Nutrition for a 12 month period. The protein levels in the three diets were 9 per cent (low protein) 14 per cent (NRC recommended level) and 20 per cent (high protein). The foals fed the low protein diet were changed to the high protein diet after 140 days when they were nine months old. ...
Pulmonary aspergillosis in a horse with myelomonocytic leukemia. Acute myelomonocytic leukemia was diagnosed in a 2-year-old Standardbred mare that had hind limb edema and fever unresponsive to antibiotics. The mare had anemia, thrombocytopenia, and leukocytosis, with circulating myeloblasts and monocytoid cells. A bone marrow specimen was hypercellular, with myeloblasts and monocytoid cells. Peroxidase, chloroacetate esterase, and alpha naphthyl acetate esterase activities were detected in many bone marrow cells. Interstitial pulmonary densities were seen radiographically. The mare was euthanatized and necropsied. Infiltrates of leukemic cells were found m...
Stromal cells from human long-term marrow cultures, but not cultured marrow fibroblasts, phagocytose horse serum constituents: studies with a monoclonal antibody that reacts with a species-specific epitope common to multiple horse serum proteins. This report describes an IgG1 mouse monoclonal antibody derived after immunization of mice with washed stromal cells from human, long-term bone marrow cultures. The antigen recognized by the antibody (BMS-1) is a carbohydrate-containing prosthetic group that is common to and specific for multiple horse serum proteins. These proteins are avidly ingested by stromal cells and concentrated in endocytic vesicles. Cultured smooth muscle cells took up the horse proteins in a similar manner to marrow stromal cells while cultured marrow fibroblasts, endothelial cells, and hepatoma cells did not. These ...
Subchondral osseous cystic lesions of the elbow of horses: conservative versus surgical treatment. Subchondral osseous cystic lesion of the elbow was diagnosed as a cause of lameness in 6 horses. Persistent lameness and signs of degenerative joint disease developed in the first 3 horses treated conservatively with confinement. Subsequently, 3 horses were each treated by extra-articular enucleation of the cystic cavity via the proximal-medial aspect of the radius. Compared with conservative management, better long-term success (determined by return of athletic soundness and less evidence of degenerative joint disease) was achieved with surgical curettage of elbow subchondral cystic lesions.
Correction of equine severe combined immunodeficiency by bone marrow transplantation. A 32-day-old horse with severe combined immunodeficiency was transplanted with equine bone marrow cells in an attempt to establish immunologic responsiveness. A histocompatible, mixed-leukocyte-culture-nonreactive, sex-matched, full sibling was used as the donor. Recipient total lymphocyte count, T and B lymphocyte numbers, and response of peripheral blood mononuclear cells to phytolectin stimulation increased by 14 days following transplantation. Circulating lymphocytes exceeded 1000 cells/microliter blood by 40 days posttransplantation, and by 170 days following transplantation, T and B lymp...
Multiple myeloma in a horse. 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.
Equine bone marrow: a quantitative analysis of erythroid maturation. The equine bone marrow responds to blood loss by increased erythropoiesis, only releasing reticulocytes into the peripheral circulation in severe chronic anemia. We have used morphometric analysis based on electron microscopy of the equine marrow to examine the maturation and release of reticulocytes. Developing red cells in the bone marrows of normal and chronically anemic horses were divided into four stages: early, intermediate, late-stage erythroblasts, and reticulocytes. Morphometric analysis of each stage included volume density of mitochondria per micron3 of cytoplasm, surface area of t...
Lag screw fixation of sagittal navicular bone fractures in five horses. A sagittal fracture of the navicular bone in five horses was treated by means of lag screw. Intra-operative radiographic monitoring and a specially developed guide apparatus was necessary to implant the screw precisely along the transverse axis of the navicular bone. Internal fixation resulted in progressive radiographic narrowing of the fracture zone. In all five patients the fracture healed (bony union) without superfluous callus formation.
Direct current stimulation of bone production in the horse: preliminary study with a “gap healing” model. The effect of a 20-microA direct-current implantable bone growth stimulator (BGS) on bone production with a "gap healing" model in the horse was evaluated. The right and left 4th metatarsal bones (Mt-4) were used in 7 adult horses to create the "gap healing" model. A 4-mm section of the Mt-4 bone was resected bilaterally in each horse. The BGS was surgically placed into the 7 left Mt-4 defects. The 7 right Mt-4 defects served as controls. Six horses survived the 16-week experimental period. Signs of pain, decreased range of limb motion, or lameness was not observed in any animal during the 16 ...
Eosinophilic myeloproliferative disorder in a horse. An eosinophilic myeloproliferative disorder resulted in edema and hemorrhagic diathesis in a 10-month-old Standardbred colt. Laboratory abnormalities included severe thrombocytopenia, anemia, mild hypoproteinemia, and marked eosinophilia. Circulating eosinophils were immature or atypical with variation in granule size, disproportionate nuclear to cytoplasmic maturation, and abnormal nuclear size and shape. Bone marrow aspirate had mainly atypical eosinophil precursors, few erythroid precursors, and no megakaryocytes. A blood transfusion and dexamethasone therapy resulted in some improvement; h...
Results of treatment of subchondral bone cysts in the medial condyle of the equine femur with an autogenous cancellous bone graft. The results of surgical treatment of 10 subchondral bone cysts, all located in the medial femoral condyle, are presented. A cancellous bone graft was used in nine cases and a two component acrylic bone cement was used in the case of an extremely large cyst. Eight out of the 10 cases made a satisfactory clinical recovery.
Monocytic leukemia in a horse. On clinical examination, a six-year-old Hassian gray gelding with a history of impaired performance, slight cough, colic, and edema of the ventral abdomen, prepuce and the legs had reduced skin turgor, pale mucous membranes, forced costoabdominal breathing, reduced venous return, enlarged lymph nodes, and splenomegaly. Hematologic findings revealed anemia, leukocytosis and a high percentage of monocytoid leukemic cells. Generalized lymphadenopathy, splenomegaly, ascites, hydrothorax, and a diffusely thickened gut wall were found at necropsy. Massive infiltration with monocytoid leukemic cells ...
