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.
A morphometric study of bone marrow megakaryocytes in foals infected with equine infectious anemia virus. Morphometric evaluation of bone marrow core biopsies was used to determine megakaryocyte (MK) numbers and MK size in nine foals with equine infectious anemia virus (EIAV)-induced thrombocytopenia. Both immunocompetent normal foals and foals with severe combined immunodeficiency (SCID) were used. Platelet counts were made three times weekly following viral infection. Bone marrow core biopsies were taken from the ilium of each foal prior to experimental infection, immediately after the onset of thrombocytopenia, and at necropsy. All foals developed thrombocytopenia by 23 days postinfection. The ...
Biosynthesis and distribution of leucocyte elastase inhibitor. Production of recombinant inhibitor. The horse leucocyte elastase inhibitor (HLEI), present in neutrophils, monocytes and bone marrow cells, is apparently a cytoplasmic protein which is not released from cells even in response to stimulation with lipopolysaccharide, phorbol ester, tumour necrosis factor alpha, interleukin-1 or elastin degradation products. Although no expression of the inhibitor was detected in neutrophils, both monocytes and bone marrow cells were efficient in its synthesis. Using a new expression vector pREST5d, recombinant inhibitor was produced in a large quantity in a soluble form, with a yield of 88 mg per ...
Osteochondrosis of the articular-epiphyseal cartilage complex in young horses: evidence for a defect in cartilage canal blood supply. The objectives of this study were to determine in horses 1) the ages at which viable cartilage canal vessels are present in the articular-epiphyseal cartilage complex of three predilection sites and one nonpredilection site of osteochondrosis (OC), 2) the prevalence of lesions of OC in these sites, and 3) whether there was an association of lesions of OC with necrotic cartilage canal blood vessels. The medial femoral condyle, lateral femoral trochlear ridge, and distal ends of the tibia and proximal phalanx were examined grossly, microradiographically, and histologically in 35 horses 18 months...
Myeloid and megakaryocytic hypoplasia in related standardbreds. Myeloid and megakaryocytic bone marrow hypoplasia in association with moderate to profound neutropenia was observed in 8 young Standardbred horses sired by the same stallion; 7 horses were intermittently thrombocytopenic. Evaluation of serial neutrophil counts in 2 horses suggested that a cyclic variation in neutrophil numbers was present, that lymphocyte numbers increased when neutrophil counts decreased, and that platelet counts decreased when neutrophil counts decreased. Preliminary bone marrow cultures indicated that myeloid progenitor cells were present and that these cells were able to r...
Use of autogenous cancellous bone grafting in the treatment of septic navicular bursitis and distal sesamoid osteomyelitis in horses. Six horses with septic navicular bursitis or distal sesamoid osteomyelitis were treated by means of surgical debridement and lavage, followed by packing of the wound created in the bottom of the foot with an autogenous cancellous bone graft. Two horses were euthanatized, one 18 months after surgery because of complications in the contralateral support limb, and one 68 days after surgery because of continuing severe lameness. Four horses were alive 9, 16, 21, and 42 months after surgery. One horse was used as a broodmare and did not have observable lameness. Two horses were being ridden. The re...
Haematological, bone marrow and clinical chemical changes in neonatal foals given canine recombinant granulocyte-colony stimulating factor. Five Thoroughbred and Quarter Horse cross foals were given 20 micrograms canine recombinant granulocyte-colony stimulating factor (rcG-CSF) per kg bwt intramuscularly (i.m.) on the day of birth and 10 micrograms rcG-CSF/kg for 13 additional days. During this time and for an additional 21 days haematology, bone marrow and clinical chemical analyses were performed. After one day of rcG-CSF administration leucocyte and neutrophil counts increased from 9.16 x 10(9)/l to 23.44 x 10(9)/l and from 6.45 x 10(9)/l to 19.61 x 10(9)/l, respectively. The counts continued to increase for the next 3-4 days ...
Pancytopenia secondary to lymphoid leukemia in three horses. Pancytopenia was observed in two 3-year-old geldings and one 11-year-old mare. All horses had a brief history (2 days to 4 weeks) of fever, anorexia, and depression. One of the three horses had blast cells present on a peripheral blood smear. Examination of the bone marrow showed substantial infiltration with neoplastic lymphoid cells. At necropsy, neoplastic cells were restricted to the bone marrow in one horse, present in bone marrow, liver, and spleen in the second horse, and reported in multiple tissues in the third horse, including bone marrow, kidneys, lung, myocardium and lymph nodes. T...
Pulsed magnetic fields improve osteoblast activity during the repair of an experimental osseous defect. The influence of pulsed low-frequency electromagnetic fields (PEMFs) on bone formation was investigated in studies of the healing process of transcortical holes, bored at the diaphyseal region of metacarpal bones of six adult horses, exposed for 30 days to PEMFs (28 G peak amplitude, 1.3 ms rise time, and 75 Hz repetition rate). A pair of Helmholtz coils, continuously powered by a pulse generator, was applied for 30 days to the left metacarpal bone, through which two holes, of equal diameter and depth, had been bored at the diaphyseal region. Two equal holes, bored at the same level in the rig...
Plasma cell myeloma in the horse. A case report and literature review. Plasma cell myelomas in horses have been reported infrequently. Data from 10 cases, 9 from the literature and 1 new case, are used to characterize the disease in the horse. Hot-blooded horses (7/10), specifically Quarter Horses (4/10), were most often affected. Median age at diagnosis was 11 years (range, 3 mo-22 yr) and both male (5) and female horses (5) were represented equally. Clinical findings included weight loss (6/8), anorexia (4/8), fever (4/8), limb edema (4/8), pneumonia (3/8), rear leg paresis/ataxia (3/8), epistaxis (3/8), palpable lymphadenopathy (2/8), and bone pain (2/8). Anem...
Generalized medullary infarction of the long bones in a horse. Generalized medullary infarction of the long bones was diagnosed in a 12-year-old Tennessee Walking Horse mare. The mare was referred after a 6-week course of shifting weight on her hind limbs, and kicking. Physical examination revealed mild stifle joint distention and withdrawal reactions to digital pressure over the long bones. Radiography revealed patchy areas of medullary sclerosis in the distal portion of each femur and proximal portion of each tibia. A full-thickness cortical and cancellous tibial biopsy revealed infarcted bone marrow, with cortical and periosteal osteonecrosis. The caus...
Effects of holmium:YAG laser on equine articular cartilage and subchondral bone adjacent to traumatic lesions: a histopathological assessment. This study was performed to investigate the effects of holmium:yttrium-aluminum-garnet (Ho:YAG) laser energy on articular cartilage and subchondral bone adjacent to traumatically created cartilage lesions in a continuous weight-bearing model. The 2.1-microns wavelength was delivered efficiently and precisely in hand-controlled contact and near-contact hard tissue arthroscopic surgery in a saline medium. Bilateral arthroscopy was performed on normal antebrachiocarpal and intercarpal joints of four adult horses. One hundred twenty traumatic lesions were created on three weight-bearing articular ...
Conservative management of fourth tarsal bone fracture in a draft horse. A fourth tarsal bone fracture was treated conservatively in an adult draft horse. Seven months after the injury, the horse had no evidence of lameness and was able to compete in athletic events. It has been suggested that conservative management of these fractures be considered for brood animals or animals used for less strenuous activities. The outcome of this case suggests that fourth tarsal bone fractures can be successfully treated in athletic animals with conservative management.
Effects of equine infectious anemia virus on hematopoietic progenitors in vitro. Direct effects of equine infectious anemia virus (EIAV) on hematopoiesis in vitro were studied. Bone marrow mononuclear cells from clinically normal horses were incubated with 100 TCID50 of EIAV/10(7) cells. These cells were cultured to assay for colonies derived from erythroid progenitors, granulocyte/monocyte progenitors, and fibroblastic progenitors. The EIAV had a selective suppressive effect on the erythroid progenitors. Colony-forming units-erythroid were suppressed to 80% of that for medium controls (P = 0.011). Burst-forming units-erythroid were suppressed to 70% of that for medium con...
Differentiation of chronic lymphocytic leukemia in the horse. A report of two cases. Chronic lymphocytic leukemia (CLL) was diagnosed in two horses: an 18-year-old Quarter Horse gelding that was examined because of edema of the prepuce and ventral abdomen; and a 20-year-old mixed breed gelding that was referred because of lymphocytosis, ventral edema, and weight loss. The first horse had enlarged peripheral lymph nodes and cool nonpainful pitting edema of the ventral abdomen and prepuce. The second horse had enlarged peripheral lymph nodes, cool nonpainful pitting edema of the ventral thorax and cranial ventral abdomen, and a 3/5 holosystolic heart murmur. The diagnosis of CLL...
Bone biopsy in the horse. 1. Method using the wing of ilium. Two hundred and five bone biopsies from the wing of ilium were taken from 52 growing and 70 older horses. The method was initially evaluated in 4 horses at post mortem and then performed in 26 horses under general anaesthesia. The technique was later developed for biopsying horses in the standing position under local anaesthesia (n = 70 adults; n = 22 foals). The core of the bone biopsy consisted of a central cancellous portion between two cortices. This type of sample allowed a complete histomorphometrical analysis. An integral part of the procedure was intravital bone labelling using fluoroc...
Incorporation of fresh and cryopreserved bone in osteochondral autografts in the horse. The structural integrity of subchondral bone in fresh and frozen osteochondral autografts was investigated at month 3 in 10 horses. Two osteochondral autografts were harvested from the lateral aspect of the lateral trochlear ridge of the left talus in each of 10 anesthetized horses. Grafts were frozen in 7.5% DMSO. After 14 days, the thawed grafts were press-fitted into drill holes in the trochlear ridges of the right stifles. A fresh graft from the right hock was implanted in each left stifle. To control for the effects of surgery, a fresh graft was transferred from the right stifle to the le...
[Hematology and cytodiagnosis of leukosis of the horse (review)]. In a review supplementary to prior evaluations further hematological or cytodiagnostic aspects respectively of equine leucosis are discussed. Leukemic nature of the disease is characterized by increased count of normal blood cells or by the presence of morphologically non-differentiated cells in circulating blood or by disorder or loss of function of blood cells respectively. Thrombocytopenia in the most cases is accompanied by anemia, leukemia and tumor cell infiltration in bone marrow. Tumor cells in circulating blood indicate their presence in bone marrow too. In cases of equine leucosis wi...
Myelophthisic pancytopenia in a pony mare. Myelophthisic pancytopenia was diagnosed in a 10-year-old pony mare with a history of recurring colic and anemia. Physical findings were unremarkable, with the exception of pale mucous membranes. Hematologic analysis revealed nonregenerative pancytopenia. Testing for equine infectious anemia and antiglobulin (Coombs) yielded negative results. The mare was treated with antibiotics, boldenone undecylenate, and corticosteroids, but a regenerative bone marrow response was not seen. Postmortem examination revealed severe myelofibrosis and multiple sites of extramedullary hematopoiesis. Myelophthisi...
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, ...