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Biomedical subjects

C R Sweeney

Publications and source records attributed to C R Sweeney.

At least 19 recordsLinked to original sources

An assay to quantitate the binding of Rhodococcus equi to macrophages.

A Rhodococcus equi radiobinding assay has been developed using organisms labeled with 3H-uracil. These labeled organisms resemble their unlabeled counterparts with respect to colony morphology, viability, and buoyant density. Bacteria routinely incorporate between 5 x 10(-3) and 5 x 10(-2) counts per minute per colony forming unit (cfu) which in this assay allows the detection of fewer than 0.2 cfu per macrophage. Once incorporated, greater than 90% of the label remains bacterial associated for at least 4 h postlabeling. The majority of the label is trichloroacetic acid precipitable, partitions into the aqueous phase following phenol/chloroform extraction and is ethanol precipitable. RNAse treatment of the ethanol precipitate abolishes label trichloroacetic acid precipitation. This radiolabeling technique has been used to quantitate the attachment of R. equi to both murine peritoneal and equine alveolar macrophages adherent to 13 mm glass coverslips. R. equi binding is dose dependent, saturable, and specific to macrophages. Further, binding is enhanced in the presence of fresh serum. Inhibition of radiolabeled bacterial binding can be obtained by competition with cold R. equi. This radiolabeled binding assay represents a crucial step in identifying the receptors on macrophages involved in the recognition of R. equi and may help to provide information on how macrophages recognize intracellular bacteria in general.

Animals

Arachidonate metabolites in bronchoalveolar lavage fluid from horses with and without COPD.

Arachidonate metabolites were measured in bronchoalveolar lavage fluid (BALF) from horses with (N = 4) and without (N = 7) chronic obstructive pulmonary disease (COPD). Prostaglandin (PG) D2, leukotriene (LT) B4 and LTC4 were present in highest concentrations in BALF from clinically normal horses. Concentrations of PGE2 and PGF were significantly higher in BALF from horses with COPD than in BALF from normal horses, but no differences were detected in thromboxane B2, 6-keto-PGF1 alpha, PGD2, LTB4 or LTC4.

Animals

Bronchoscopy of the horse.

The endobronchial anatomy of 12 lung specimens from horses and 12 healthy, standing, sedated horses was evaluated, using a 200-cm-long, 9.5-mm-diameter videoendoscope. On the basis of these findings, the nomenclature system of Amis and McKiernan was modified for identification of airways of horses during bronchoscopy. Lobar bronchi are identified on the basis of the side of the bronchial tree on which they were found and the order in which they originated from the primary bronchus. Thus, RB1, RB2, and RB3 referred to right cranial lobar bronchus, respectively. On the left side, the designation of LB1 and LB2 refer to the left cranial lobar bronchus and the left caudal lobar bronchus, respectively. Segmental bronchi are identified by consecutive numbers in the order of origination from the lobar bronchus. The direction of the segmental bronchus was denoted by the capital letter D (dorsal), V (ventral), L (lateral), M (medial), R (rostral), and C (caudal). Subsegmental bronchi were identified in the order of origination from the segmental bronchi, using lower case letters (eg, RB2, 1V, a or RB2, 1V, aV). For subsequent branching of the subsegmental bronchi, the branches were numbered consecutively by their order of origination (eg, RB2, 1V, aV, 1D).

Animals

Cytologic findings of tracheobronchial aspirates from 66 thoroughbred racehorses.

Tracheobronchial aspirates obtained from 66 healthy Thoroughbred racehorses in training at the same track were examined. Twenty-seven percent of the horses had greater than 20% neutrophils in the aspirate. Eosinophils, mast cells, giant cells, and Curschmann's spirals of mucus were observed in 94, 83, 65, and 42% of the horses, respectively. Hemosiderophages were observed in 86% of the horses, half of which had previous confirmation of exercise-induced pulmonary hemorrhage. Although fungal elements were seen in 70% of the horses, bacteria were detected in only 3% of the horses. The authors conclude that inflammatory airway disease is widespread in the racing Thoroughbred population.

Animals

Effects of lung site and fluid volume on results of bronchoalveolar lavage fluid analysis in horses.

Bronchoalveolar lavage (BAL) fluid was analyzed in healthy horses, using different lavage fluid volumes and lung sites. The only significant difference in the cellular composition of BAL fluid between the right and left lungs was the mast cell numbers, which were significantly higher in the left lung. Total cell count ranged from 34 to 330 cells/microliter for the right lung and 43 to 330 cells/microliter for the left lung. Percentage of neutrophils ranged from 1 to 7% in the right lung and 1 to 5% in the left lung. The small-volume (50 ml) lavage had a greater percentage of neutrophils and a lesser percentage of mast cells in the large-volume (350 ml) lavage. Statistical difference in the composition of BAL fluid recovered was not detected between the 3 sequential 100-ml lavages and a single 300-ml lavage, except that macrophages were significantly higher in the 3 sequential 100-ml lavages. Values for BAL fluid analysis in healthy horses have varied considerably and this variation is from a failure to adhere to any standard technique for volume of fluid infused.

Animals

Bronchoalveolar lavage fluid cytologic findings in horses with pneumonia or pleuropneumonia.

Bronchoalveolar lavage was performed in 22 horses with pneumonia or pleuropneumonia. All horses had clinical evidence of pneumonia or pleuropneumonia on the basis of physical, radiographic, ultrasonographic, tracheobronchial aspirate or post-mortem findings. Results of lavage fluid analysis were normal in 9 horses, equivocal in 3 horses, and abnormal in 10 horses. Abnormal lavage fluid had increased total cell count, increased relative and absolute neutrophil counts, degenerative neutrophils, and decreased relative and absolute macrophage and lymphocyte counts.

Animals

Endoscopic findings in the upper respiratory tract of 678 Thoroughbred racehorses.

The frequency of upper respiratory tract abnormalities was determined in a selected population of racing Thoroughbreds. The prevalence of pharyngeal lymphoid hyperplasia was 34.2%; left laryngeal hemiplegia was 1.8%; and epiglottic entrapment was 0.74%. Excluding pharyngeal lymphoid hyperplasia and tracheal exudate, 3.7% of the population examined had upper respiratory tract abnormalities.

Animals

Clinical use of metronidazole in horses: 200 cases (1984-1989).

Case records of 200 horses treated with metronidazole were reviewed. Horses were treated for respiratory tract infections (90 cases), peritonitis or abdominal abscess (39 cases), celiotomy (49 cases), orthopedic infections (6 cases), and miscellaneous soft tissue infections (16 cases). Bacteria of the genus Bacteroides were most prevalent (55 of 167 anaerobic isolates). Metronidazole was always used in combination with other antimicrobial drugs. Only 4 of the 200 horses had signs of adverse effects associated with metronidazole treatment. Those 4 horses had poor appetite that resolved when metronidazole treatment was discontinued.

Animals

Aerobic and anaerobic bacterial isolates from horses with pneumonia or pleuropneumonia and antimicrobial susceptibility patterns of the aerobes.

Frequency of aerobic and anaerobic isolates in 327 aspirates and in 123 pleural fluid samples from 327 horses with pneumonia or pleuropneumonia and antimicrobial susceptibility patterns of the aerobes were reported. Of the 327 horses, 75% survived, 20% were euthanatized, and 5% died. Tracheobronchial aspirates or pleural fluid specimens from 25 of the horses did not yield growth. Of the remaining 302 horses, 221 had only aerobic organisms isolated, whereas only anaerobes were isolated from 6 of the 302 horses. The remaining 75 horses had mixed aerobic and anaerobic bacterial infections. The survival rates for horses with aerobic only isolates was twice that of horses with anaerobic isolates. The aerobic bacteria most frequently isolated were beta-Streptococcus spp, Pasteurella spp, Escherichia coli, and Enterobacter spp. The anaerobic species most frequently isolated were Bacteroides spp and Clostridium spp.

Animals

Exercise-induced pulmonary hemorrhage.

This article addresses many aspects of exercise-induced pulmonary hemorrhage (EIPH). Reports of the prevalence, effect on performance, and the clinical signs and means of diagnosis of EIPH are included. Radiologic and scintigraphic findings in horses with EIPH are reported. Pathogenesis and treatment are discussed.

Animals

Pleuroscopic diagnosis of disseminated hemangiosarcoma in a horse.

A 7-year-old Thoroughbred mare was examined because of persistent bilateral epistaxis and respiratory distress. Evidence of bilateral pleural effusion was found during physical examination, and a large amount of serosanguineous fluid was drained from the right side of the thorax. Cytologic examination and bacteriologic culture of the transtracheal aspirate and pleural fluid did not yield evidence of sepsis. A coagulation profile was unremarkable. Radiographic and echographic changes were seen in the lung parenchyma. Pleuroscopy, with the horse standing, revealed numerous dark nodules on the pleura, diaphragm, and lung surface. On the basis of biopsy and necropsy findings, the histopathologic diagnosis was disseminated hemangiosarcoma.

Animals

Effects of furosemide on the racing times of Thoroughbreds.

The effects of furosemide on the racing times of 79 horses without exercise-induced pulmonary hemorrhage (EIPH) and 52 horses with EIPH were investigated. Racing times were adjusted to 1-mile equivalent racing times by 2 speed handicapping methods, and analysis of covariance was used to adjust actual racing times by winning time and distance for each race. All 3 methods of determining racing time indicated that geldings without EIPH had significantly faster racing times (P less than 0.05) when given furosemide before racing than when furosemide was not given before racing. Females and colts without EIPH were determined to have faster racing times when furosemide was given before racing, but the difference was not significant. Geldings with EIPH had significantly faster racing times (P = 0.0231) when given furosemide before racing, as determined by one of the speed handicapping methods. There was a strong correlation (range 0.9314 to 0.9751) between the 1-mile equivalent racing times, as determined by the 2 speed handicapping methods for horses with and without EIPH. Furosemide failed to prevent the development of EIPH in many horses that were previously considered to be EIPH-negative. When given furosemide, 62 (25.3%) of 235 EIPH-negative horses were EIPH-positive after racing. Furosemide had questionable efficacy for prevention of EIPH in known EIPH-positive horses. Thirty-two (61.5%) of 52 EIPH-positive horses given furosemide before a race remained EIPH-positive after that race.

Animals

Immunoreactive prostaglandin production by equine monocytes and alveolar macrophages and concentrations of PGE2 and PGF in bronchoalveolar lavage fluid.

Because of their capacity to produce prostanoids, alveolar macrophages may play a part in the pathogenesis of chronic obstructive pulmonary disease (COPD). Cultured equine alveolar macrophages and peripheral blood monocytes synthesised mainly prostaglandin (PG)F and PGE2. They also synthesised smaller quantities of PGI2, measured as the stable metabolite 6-keto-PGF1 alpha, and thromboxane B2. Concentrations of immunoreactive PGF and PGE2 were measured in bronchoalveolar lavage fluid collected from clinically normal horses (n = 3) and horses with COPD (n = 3). None of the normal horses had detectable concentrations of prostaglandins in lavage fluid, but fluid from all horses with COPD contained PGE2 (238 +/- 119 pg ml-1) and fluid from one of the three horses with COPD contained PGF (120 pg ml-1).

Animals

Comparison of bacteria isolated from specimens obtained by use of endoscopic guarded tracheal swabbing and percutaneous tracheal aspiration in horses.

Results of bacteriologic culture of specimens obtained from 14 horses with pneumonia and from 15 horses that were clinically healthy (nonpneumonia group) were compared. Specimens were obtained by use of an endoscopic guarded tracheal swabbing method and percutaneous tracheal aspiration. The percentage of agreement between the 2 tracheal specimens for the horses of the pneumonia group was 79% for aerobic isolates and 100% for anaerobic isolates. The percentage of agreement between results of the 2 tracheal specimens for horses of the nonpneumonia group was 80% for aerobic organisms and 93% for anaerobic organisms. The endoscopic guarded swabbing method described here for obtaining specimens from the lower airways for bacteriologic culture did not always prevent contamination. Results of the study suggested that this endoscopic swabbing technique has merit and should be considered as an alternative to the tracheal aspiration method. Pseudomonas sp and any anaerobic bacteria that are isolated must be viewed as potential contaminants of the endoscopic swab specimen and may not be involved in the primary pulmonary disease.

Animals

Thoracic neoplasia in equids: 35 cases (1967-1987).

Thirty-two horses and 3 ponies had neoplasia involving the thoracic cavity. Lymphosarcoma of the thorax was found in 19 (54.2%) of the equids. The other 16 equids had metastatic adenocarcinoma (7 horses; 20%), metastatic squamous cell carcinoma (5 equids; 14.3%), metastatic hemangiosarcoma (3 equids; 8.6%) or undifferentiated sarcoma (1 horse; 2.9%). Thoracic neoplasia was diagnosed before death in 15 equids (42.9%).

Adenocarcinoma

Hypertrophic osteopathy in a pony with a pituitary adenoma.

Hypertrophic osteopathy was diagnosed in a pony that had no antemortem or postmortem evidence of an intrathoracic lesion. With a history of hirsutism in an aged pony, a pituitary adenoma was suspected, and evaluation of plasma cortisol and insulin values and their response to thyrotropin-releasing hormone supported the diagnosis.

Adenoma