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Biomedical subjects

K G Magdesian

Publications and source records attributed to K G Magdesian.

At least 19 recordsLinked to original sources
PubMed2007

Bacteraemia in neonatal foals: clinicopathological differences between Gram-positive and Gram-negative infections, and single organism and mixed infections.

REASONS FOR PERFORMING STUDY: Treatment for bacteraemia in foals must be started before the identity of the causative organism is known. Information aiding selection of effective antimicrobials should improve outcome. OBJECTIVES: To describe differences in clinical and clinicopathological data and outcome in foals with bacteraemia due to different classes of bacteria. METHODS: Records of foals with a positive blood culture, age < 10 days and presenting to a university hospital 1995-2004, were reviewed. Bacterial culture results, subject details, historical information, physical examination findings at admission and clinicopathological data generated during the first 48 h of hospitalisation were analysed. Results from foals with Gram-positive or Gram-negative organisms, single or mixed organism bacteraemias, and with bacteraemia due to 3 commonly isolated organisms were compared. RESULTS: Eighty-five foals met the inclusion criteria. Gram-negative organisms (n = 59) Gram-positive organisms (n = 13) or multiple organisms (n = 19) were cultured from individual foals. Foals with Gram-negative bacteraemia had lower total white blood cell and lymphocyte counts at admission than did those from which only Gram-positive bacteria were cultured. Mixed organism bacteraemia was associated with tachycardia, increased serum concentrations of sodium, chloride and urea nitrogen, acidosis, respiratory distress, recumbency on admission and nonsurvival. Actinobacillus spp. infections were associated with leucopenia, neutropenia, lymphopenia and depression on hospital admission. CONCLUSIONS AND POTENTIAL RELEVANCE: Recognising particular patterns of clinical and clinicopathological findings associated with infection with specific groups of bacteria may, in the future, aid antimicrobial selection and influence prognosis in bacteraemic foals.

Animals↗
PubMed2006

Idiopathic immune-mediated polysynovitis in three horses.

This paper describes the clinical, laboratory and histological findings in three horses with immune-mediated polysynovitis; they had lost weight, suffered intermittent fever, were lethargic and stiff, and had effusions in several joints. Laboratory abnormalities included anaemia, leucocytosis, hyperfibrinogenaemia and hyperglobulinaemia. The diagnosis was based on the presence of a suppurative, non-septic inflammation in at least two different joints in each of the horses and the presence of immunoglobulins in the synovial membrane of one of them. The horses were treated with a combination of dexamethasone and azathioprine, and responded well to the initial treatment. Twenty months after its last re-evaluation, the first horse was being maintained on azathioprine because similar clinical signs had recurred after the cytotoxic drug was discontinued; the second horse was finishing a tapering course of prednisolone 15 months after its first examination, and the third horse was euthanased five months after it was first examined as a result of an unrelated injury.

Animals↗
PubMed2006

Multicentric T-cell lymphosarcoma in an alpaca.

A two-year-old female alpaca with multicentric lymphosarcoma presented because of progressive weakness and recumbency. The diagnosis of lymphosarcoma was based on the detection of immature and atypical lymphocytes in a lumbosacral CSF sample. Post mortem examination confirmed multicentric lymphosarcoma involving multiple organs. Immunophenotyping using cross reactive T- and B-cell antibodies characterized the tumour as a T-cell lymphosarcoma.

Animals↗
PubMed2004

Immunoglobulin A monoclonal gammopathy in two horses with multiple myeloma.

The clinical findings in two horses with secretory multiple myeloma and secondary immunoglobulin A (IgA) monoclonal gammopathy were non-specific and included weight loss, pale mucous membranes, limb oedema and bacterial respiratory tract infection. Consistent laboratory abnormalities included hyperproteinaemia, hyperglobulinaemia, hypoalbuminaemia and hypercalcaemia. The diagnosis was based on the presence of IgA monoclonal gammopathy in serum and urine and bone marrow plasmacytosis (> 10 per cent). One horse was euthanased; it had neoplastic plasma cell infiltrates in its kidneys, spleen, liver, bone marrow, myocardium and adrenal glands. The other horse was treated for a bacterial pneumonia and was still alive six months after it was first examined.

Animals↗
PubMed2003

Idiopathic granulomatous pneumonia in seven horses.

The history, clinical signs and pathological findings in seven adult horses with histologically confirmed idiopathic granulomatous disease, primarily of the lungs, are reviewed. They ranged in age from eight to 21 years, five were geldings and two were females, they belonged to five breeds and there were no seasonal or geographical associations. The primary clinical signs were chronic weight loss, exercise intolerance and respiratory distress which did not respond to conventional treatment. The most consistent physical findings were depression, anorexia, tachycardia, tachypnoea and adventitious lung sounds. Thoracic radiographs revealed a diffuse, structured, nodular, interstitial pulmonary pattern in each horse. Haematological measurements suggested a chronic inflammatory process and the cytology of transtracheal washes was consistent with a mild suppurative inflammation. Idiopathic granulomatous pneumonia was confirmed histologically in each of the horses, either postmortem or by a lung biopsy. The horses responded poorly to medical treatment and only one of three treated horses is still alive.

Animals↗
PubMed2003

Purpura haemorrhagica in 53 horses.

The medical records of 53 horses with purpura haemorrhagica were reviewed. Seventeen of them had been exposed to or infected with Streptococcus equi, nine had been infected with Corynebacterium pseudotuberculosis, five had been vaccinated with S. equi M protein, five had had a respiratory infection of unknown aetiology, and two had open wounds; the other 15 cases had no history of recent viral or bacterial infection. The horses were between six months and 19 years of age (mean 8.4 years). The predominant clinical signs were well demarcated subcutaneous oedema of all four limbs and haemorrhages on the visible mucous membranes; other signs included depression, anorexia, fever, tachycardia, tachypnoea, reluctance to move, drainage from lymph nodes, exudation of serum from the skin, colic, epistaxis and weight loss. Haematological and biochemical abnormalities commonly detected were anaemia, neutrophilia, hyperproteinaemia, hyperfibrinogenaemia, hyperglobulinaemia and high activities of muscle enzymes. All of the horses were treated with corticosteroids; 42 also received non-steroidal anti-inflammatory drugs and 26 received antimicrobial drugs. Selected cases received special nursing care, including hydrotherapy and bandaging of the limbs. Most of the horses were treated for more than seven days and none of them relapsed. Forty-nine of the horses survived, one died and three were euthanased, either because their severe clinical disease failed to respond to treatment or because they developed secondary complications. Two of the four non-survivors had been vaccinated against S. equi with a product containing the M protein, one had a S. equi infection and the other had a respiratory infection of undetermined aetiology.

Adrenal Cortex Hormones↗
PubMed2002

Pulmonary coccidioidomycosis in a neonatal foal.

A 13-day-old foal with profound tachypnoea and respiratory distress was examined. Thoracic radiographs revealed a severe, diffuse miliary pattern, and the foal was markedly hypoxaemic. It failed to improve with empirical treatment, and was euthanased. Lesions associated with Coccidioides immitis infection were identified at postmortem examination, and were limited to the lower respiratory tract.

Animals↗
PubMed2001

Suspected protozoal myeloencephalitis in a two-month-old colt.

A two-month-old Appaloosa colt developed neurological signs shortly after birth involving deficits affecting cranial nerves IV, VII, VIII, IX, X and XII, and possibly nerve VI. The most likely differential diagnoses were congenital anomalies, meningoencephalitides, trauma or nutritional causes. The foal was investigated by the analysis of cerebrospinal fluid (CSF), electromyelography (EMG), brain auditory evoked responses, magnetic resonance imaging (MRI), peripheral nerve biopsy, and Western blot analysis for the presence of intrathecal antibodies to Sarcocystis neurona, the causative agent of equine protozoal myeloencephalitis. Significantly abnormal EMG findings included spontaneous electrical activity of the tongue, suggesting denervation. The MRI was useful in ruling out masses, congenital anomalies and focal abscessation. The cytology of CSF revealed mild mononuclear reactivity. Western blot testing of CSF was positive, indicating the intrathecal presence of antibodies to S neurona. The foal was treated with pyrimethamine and trimethoprim-sulphadiazine for two months and returned to nearly normal neurologic status.

Animals↗
PubMed1998

Pharmacokinetics of a high dose of gentamicin administered intravenously or intramuscularly to horses.

OBJECTIVE: To evaluate pharmacokinetics of a high dose of gentamicin administered i.v. or i.m. to horses. DESIGN: Repeated-measures study. ANIMALS: 6 clinically normal female adult stock-type horses. PROCEDURE: All horses were given gentamicin (6.6 mg/kg [3 mg/lb] of body weight), i.v. and i.m., in a two-way cross-over design. Serum gentamicin concentrations were measured during a 24-hour period. RESULTS: Plasma concentration curves were consistent with a two-compartment model. Maximum plasma gentamicin concentrations were 71.9 +/- 15.7 micrograms/ml (0 hours after injection) and 22.0 +/- 4.9 micrograms/ml (1.31 hours after injection) for the i.v. and i.m. groups, respectively. Area under the curve (AUC) was 116.6 +/- 14.5 and 116.3 +/- 14.6 micrograms.h/ml for the i.v. and i.m. groups, respectively. Elimination half-life for the IV group was 3.0 +/- 2.8 hours. Trough concentrations were < 2 micrograms/ml for > 15 and > 12 hours for the i.v. and i.m. groups, respectively. Significant changes were not detected in clinicopathologic variables before and after administration of gentamicin. CLINICAL IMPLICATIONS: Administration of a high dose of gentamicin i.v. or i.m. resulted in peak plasma concentrations, AUC, and minimum trough plasma concentrations. Results indicate once-daily administration of gentamicin might be as efficacious and safe as multiple-dose daily administration in accordance with traditional low-dose regimens, similar to those used in other species.

Animals↗
PubMed1992

Temporal effects of plasmapheresis on serum proteins in horses.

The temporal response of blood and serum proteins to chronic plasmapheresis was determined in 8 horses used in a commercial antibody enterprise. Plasmapheresis of between 4 and 11 L induced significant decreases in total protein, albumin, and IgG values. With the exception of a high hematocrit value for the first postplasmapheresis blood sample, there were no changes in erythrocyte or leukocyte measurements, and no changes in the proportions of serum protein in an electrophoretic profile. Regression equations generated for recovery of proteins after plasmapheresis indicated a return to preplasmapheresis values of total protein and albumin at approximately 1 month. Complications of repeated plasmapheresis were not detected when plasma extractions were done between 7 and 19 times at 30-day intervals.

Animals↗
PubMedDate not supplied

Ameloblastic carcinoma in a horse.

The clinical, gross morphological, histological and immunohistochemical characteristics of an ameloblastic carcinoma in a 30-year-old Quarter Horse mare are reported. This tumour was fast growing, locally invasive and destructive. Histologically, it showed an infiltrative pattern of large islands, broad sheets and, at the periphery, small cords of moderately pleomorphic round, oval to spindle-shaped cells. Immunohistochemical evaluation revealed positive labelling for vimentin, cytokeratin 5/6 and cytokeratin 14. In the oral cavity of human beings, this immunolabelling pattern is unique for the embryonal enamel organ and tumours of ameloblastomatous epithelial origin, which strongly supports the diagnosis of equine ameloblastic carcinoma.

Ameloblastoma↗
PubMedDate not supplied

Application of Sartwell's model (lognormal distribution of incubation periods) to age at onset and age at death of foals with Rhodococcus equi pneumonia as evidence of perinatal infection.

The distributions of the incubation periods for infectious and neoplastic diseases originating from point-source exposures, and for genetic diseases, follow a lognormal distribution (Sartwell's model). Conversely, incubation periods in propagated outbreaks and diseases with strong environmental components do not follow a lognormal distribution. In this study Sartwell's model was applied to the age at onset and age at death of foals with Rhodococcus equi pneumonia. The age at onset of clinical signs and age at death were compiled for 107 foals that had been diagnosed with R. equi pneumonia at breeding farms in Argentina and Japan. For each outcome (disease and death), these data followed a lognormal distribution. A group of 115 foals with colic from the University of California were used as a comparison group. The age at onset of clinical signs for these foals did not follow a lognormal distribution. These results were consistent with the hypothesis that foals are infected with R. equi during the 1st several days of life, similar to a point-source exposure.

Actinomycetales Infections↗
PubMedDate not supplied

Acute hemoperitoneum in horses: a review of 19 cases (1992-2003).

The medical records of 19 horses with acute hemoperitoneum were reviewed. The causes for the hemoperitoneum were idiopathic (8 horses), splenic hematoma with capsular tear (7), bleeding from the reproductive tract (3), multicentric hemangiosarcoma (1), and systemic amyloidosis (1). The affected horses were between 4 and 32 years of age (median 11.5 years). The most consistent findings on initial examination were depression, tachycardia, tachypnea, pale mucous membranes, prolonged capillary refill time, colic, and abdominal discomfort. Less common clinical signs included abdominal distention, profuse sweating, ataxia, and broad ligament mass palpated on rectal examination. Clinicopathologic abnormalities commonly detected were anemia, neutrophilia, lymphopenia, thrombocytopenia, hypoproteinemia, hypocalcemia, azotemia, increased creatinine kinase, and sorbitol dehydrogenase activity. Hemoperitoneum was diagnosed on the basis of abdominocentesis, transabdominal ultrasonography, and postmortem examination. Sixteen horses were treated, and 3 horses were euthanized at owners' request because of severe clinical signs. The treatment consisted of the administration of intravenous fluids, plasma or blood transfusion, nonsteroidal drugs, antimicrobial drugs, and antifibrinolytic and procoagulant agents. Rapid clinical deterioration was observed in 2 horses, necessitating euthanasia. The remaining 14 horses survived the abdominal bleeding (survival rate 74%) and were discharged 3-15 days (median 7.0 days) after presentation. Postmortem examination of the 6 nonsurvivors showed massive abdominal hemorrhage from splenic hematoma with capsular tear (2 horses), multicentric hemangiosarcoma with liver rupture (1), systemic amyloidosis with splenic hematoma and capsular tear (1), and bilateral ruptured ovarian hematomas (1). In one horse, no origin of the bleeding could be determined during postmortem examination.

Animals↗