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Abstract

Objective—To evaluate changes in cysteinyl leukotriene (LT) concentrations in urine and bronchoalveolar lavage fluid (BALF) in cats with experimentally induced asthma.

Animals—19 cats with experimentally induced asthma and 5 control cats.

Procedure—Cats were sensitized to Bermuda grass or house dust mite allergen, and phenotypic features of asthma were confirmed with intradermal skin testing, evaluation of BALF eosinophil percentages, and pulmonary function testing. A competitive ELISA kit for LTC4, LTD4, and LTE4 was used for quantitative analysis of LTs. Urinary creatinine concentrations and BALF total protein (TP) concentrations were measured, and urinary LT-to-creatinine ratios and BALF LTto- TP ratios were calculated.

Results—Mean urinary LT-to-creatinine ratios did not differ significantly between control cats and allergensensitized cats before or after sensitization and challenge exposure with saline (0.9% NaCl) solution or allergen, respectively. In BALF, the mean LT-to-TP ratio of control cats did not differ significantly before or after sensitization and challenge exposure with saline. Asthmatic cats had BALF LT-to-TP ratios that were significantly lower than control cats at all time points, whereas ratios for asthmatic cats did not differ significantly among the various time points.

Conclusions and Clinical Relevance—Although LTs were readily detectable in urine, no significant increases in urinary LT concentrations were detected after challenge in allergen-sensitized cats. Spot testing of urinary LT concentrations appears to have no clinical benefit for use in monitoring the inflammatory asthmatic state in cats. The possibility that cysteinyl LTs bind effectively to their target receptors in BALF and, thus, decrease free LT concentrations deserves further study. (Am J Vet Res 2003;64:1449–1453)

Full access
in American Journal of Veterinary Research

Summary

Fiberoptic bronchoscopy was performed in pigs to assess bacterial contamination of bronchoalveolar lavage fluids (balf) obtained by use of the method and to determine the aerobic bacterial species in bronchoalveolar airways of healthy pigs. Bacterial contamination of balf caused by insertion of the bronchoscope was evaluated, using a chromogenic bacterial tracer strain, and was found to be 0.22% of total colony-forming units (cfu), with range between 0 and 1.6%. A total of 164 pulmonary-healthy pigs from 6 closed herds were selected. The balf obtained from these pigs were examined bacteriologically. Bacteria could not be isolated from 10.4% of all balf; 5.5% of the balf samples yielded pure cultures; and 84.1% yielded mixed aerobic bacterial growth. In balf from 29.2% of the pigs, ≤ 5 × 102 cfu of bacteria/ml were isolated. The total number of bacteria in balf from 50% of the pigs varied between 5 × 102 and 103 cfu/ml; 10.4% of balf samples contained between 103 cfu/ml and 5 × 103 cfu/ml. More than 1 bacterial species were isolated from a single lung lavage of 84.1% of the pigs. Up to 6 species were isolated from a single balf sample. A total of 443 bacterial isolates were differentiated into 25 bacterial genera and species. Samples of balf yielded staphylococci (67.6%: Staphylococcus hyicus from 13.4% of the samples and S aureus from 2.4%), α-hemolytic streptococci (49.4%), Escherichia coli (42.1%), non-hemolytic streptococci (26.2%), Klebsiella spp (18.3%), micrococci (12.8%), and Coryneformes (11.0%). Other bacterial species were found, but less frequently. In our study, balf from all pigs yielded < 5 × 103 cfu/ml. Thus, low numbers of bacteria known to be facultative pathogens were isolated from balf without causing detectable pneumonia.

Free access
in American Journal of Veterinary Research

SUMMARY

Objective

To correlate indices of airway reactivity to bronchoalveolar lavage (BAL) fluid cytologic features in horses with a recent decline in exercise tolerance.

Animals

20 actively working horses from 2 to 24 years old.

Procedure

Bronchoalveolar lavage fluid samples were obtained and analyzed. Forced oscillatory mechanics (1-7 Hz) technique was used for measurements of total respiratory system resistance (RRS), compliance (CRS), and resonant frequency (fres). Changes in RRS (1 Hz) during histamine challenge were used to generate histamine dose-response curves, from which the provocative concentrations that evoked a 75 or 100% increase in baseline RRS (PCRRS75 and PCRRS100, respectively) were determined. Age, sex, baseline lung mechanics, and BAL cytologic findings were correlated with PCRRS75 and PCRRS100.

Results

No horse of the study had clinical signs or history of obstructive pulmonary disease or increased percentage (> 7%) of neutrophils in bronchoalveolar lavage fluid samples. Mean (± SEM) RRS, CRS, and fres were 0.67 ± 0.06 cm of H2O/L/s, 0.52 ± 0.04 L/cm H2O, and 2.46 ± 0.02 Hz, respectively. There was no correlation between age or sex, and RRS, CRS, fres, PCRRS75, or PCRRS100. There was a significant correlation (rs = −0.78, P < 0.001) between percentage of BAL fluid mast cells and PCRRS75 or PCRRS100, but correlation with other cell types and indices of airway reactivity were not observed.

Conclusion

The strong association between mast cell percentage in BAL fluid and airway reactivity in this group suggests that mast cell products may contribute to bronchospasm, airway wall thickening, and/or loss of elastic recoil, which underlie airway hyperreactivity. Alternatively, mast cells may contribute to nonspecific airway reactivity in horses through unknown mechanisms. (Am J Vet Res 1998;59:176–181)

Free access
in American Journal of Veterinary Research

Abstract

Objective

To determine whether oral administration of erythromycin alters the inflammatory response to bronchoalveolar lavage (BAL) in young horses.

Animals

12 healthy, unweaned, mixed-breed foals of either sex, between 2 and 4 months old.

Procedure

BAL was performed; 250 ml of phosphate-buffered saline solution (300 mOsm, pH 7.4) was administered in 50-ml aliquots. Foals were carefully monitored for 4 days, then erythromycin base (25 mg/kg of body weight, PO, q 12 h) was given to foals of the treated group. After 4 days, foals were re-anesthetized, and the same lung was relavaged. Cytologic examination was performed on BAL fluid (BALF) samples from both groups of foals. At 12 hours after administration of the final dose, erythromycin A and anhydroerythromycin A concentrations were determined in plasma of treated foals.

Results

In the second BALF sample from the same lung of control foals, percentage of neutrophils was significantly increased (3 ± 38.0%), compared with that from erythromycin-treated foals (4.88 ± 3.66%, P < 0.05), and was associated with apparent decrease in the ability of BALF cells from erythromycin-treated foals to migrate toward a chemoattractant source. Significantly fewer BALF cells adhered to a cell culture substratum after erythromycin treatment of foals. Erythromycin A was not detected in plasma of any treated foal at the time of the second BAL; anhydroerythromycin A, a degradation product of erythromycin, was detected in plasma of 5 of 6 foals (mean concentration, 0.2 ± 0.06 µg/ml).

Conclusion and Clinical Relevance

BAL induces neutrophilic inflammation, which persists for at least 4 days in the lungs of young horses. Erythromycni (25 mg/kg, PO, q 12 h) diminishes this inflammatory response through a mechanism that may involve alteration of BALF cell function. Degradation of erythromycin to biologically active products or presence of parent drug in pulmonary secretions may be responsible for alterations in pulmonary lavage cell Chemotaxis and adherence. Erythromycin administered orally to foals at clinically relevant doses appears to have nonantimicrobial effects that may interfere with host cell metabolism and decrease inflammatory reponses in airways. (Am J Vet Res 1997;58:56–61)

Free access
in American Journal of Veterinary Research

Abstract

Objective—To determine the effects of an external nasal dilator strip on cytologic characteristics of bronchoalveolar lavage (BAL) fluid in racing Thoroughbreds.

Design—Clinical trial.

Animals—23 Thoroughbred racehorses in active training.

Procedure—Each horse raced on 2 occasions: once while wearing an external nasal dilator strip and once while not. Bronchoalveolar lavage was performed 12 to 18 hours after each race, and BAL fluid was analyzed for RBC and leukocyte counts and hemosiderin content.

Results—Mean ± SEM count of RBCs in BAL fluid when horses raced without the nasal dilator strip (84.6 ± 27.5 cells/µL) was not significantly different from count when they raced with it (41.7 ± 12.2 cells/µL). Horses were grouped as having mild or severe bleeding on the basis of RBC count in BAL fluid after horses raced without the nasal dilator strip. Mean count when horses with severe bleeding raced without the nasal dilator strip (271.0 ± 63.7 cells/µL) was significantly higher than mean count when these horses raced with the strip (93.8 ± 37.6 cells/µL). Mean count of lymphocytes in BAL fluid was significantly lower after horses raced with the external nasal dilator strip.

Conclusions and Clinical Relevance—Results suggest that use of an external nasal dilator strip in Thoroughbred racehorses may decrease pulmonary bleeding, particularly in horses with severe exerciseinduced pulmonary hemorrhage. ( J Am Vet Med Assoc 2004;224:558–561)

Full access
in Journal of the American Veterinary Medical Association

Summary

Effects of triamcinolone acetonide (ta) on pulmonary function, bronchoalveolar lavage cytologic features and serum cortisol concentration, were studied in 5 control horses and 5 horses with chronic obstructive pulmonary disease (copd). In experiment 1, horses were brought in from pasture 3 weeks before administration of 1 injection of ta (0.09 mg/kg of body weight, im), and were stabled in dusty conditions throughout the experimental period. Measurements of respiratory rate (f), tidal volume, minute ventilation, expiratory-to-inspiratory time ratio, maximal change in transpulmonary pressure (ΔPL), pulmonary resistance (RL), and dynamic compliance (Cdyn) were obtained during quiet breathing, immediately before (baseline) and 1, 2, 3, 5, and 9 weeks after administration of ta. Pulmonary airway cells were collected by bronchoalveolar lavage while horses were at pasture, at baseline, and 2, 5, and 9 weeks after ta administration. Serum cortisol concentration was measured before and after adrenocortical stimulation with 100 IU of adrenocorticotropic hormone, 1 week prior to ta administration, and 4 and 8 weeks thereafter. In experiment 2, 4 months after ta injection, pulmonary function measurements were repeated in all horses immediately before and 30 minutes after administration of atropine (0.015 mg/kg, iv), to evaluate the reversibility of airway obstruction.

In experiment 1 at baseline, COPD-affected horses had significantly (P < 0.05) higher values than did controls for f, ΔPL, RL, and percentage of neutrophils, and had lower values for Cdyn and percentage of lymphocytes and macrophages. There were significant reductions in ΔPL and RL, and increase in macrophage percentage after ta administration in copd-affected horses only. The degree and duration of these changes varied among individual copd-affected horses, but ΔPL, and RL, values had returned to or were above baseline in all horses 5 weeks after treatment. Baseline cortisol concentration was decreased 4 weeks after ta administration, but the mean increase in cortisol values after adrenocorticotropic hormone stimulation was similar to that observed prior to treatment.

In experiment 2, values of ΔPL, RL, and Cdyn, after atropine administration were similar to those of controls in the 2 copd-affected horses that had improved most after ta, but were only partially improved in the 3 other horses, indicating possible irreversible lesions in the latter.

Free access
in American Journal of Veterinary Research

Abstract

Objective—To evaluate the association among clinical signs, results of cytologic evaluation of bronchoalveolar lavage (BAL) fluid, and measures of pulmonary function in horses with inflammatory respiratory disease.

Animals—9 healthy horses, 5 horses with inflammatory airway disease (IAD), and 9 horses with chronic obstructive pulmonary disease (COPD).

Procedure—Clinical examination, lung function tests, and BAL were performed on each horse.

Results—Standard lung mechanics of horses with exacerbated COPD differed significantly from those of healthy horses; however, there were few differences among horses with IAD, horses with COPD during remission, and healthy horses. Most variables for forced expiration (FE) in horses with COPD or IAD differed significantly from those for healthy horses. Results of clinical examination had low to moderate sensitivity and predictive values for a diagnosis of COPD (range, 67 to 80%). Results of FE tests had high sensitivity, specificity, and predictive values for a diagnosis of COPD (79 to 100%), and results of standard lung mechanics tests had low sensitivity and predictive values (22 to 69%). Percentage of neutrophils in BAL fluid was highly sensitive (100%) but moderately specific (64%) for a diagnosis of COPD.

Conclusion and Clinical Relevance—Clinical examination is moderately accurate for establishing a diagnosis of COPD. Forced expiration tests can specifically detect early signs of airway obstruction in horses with COPD and IAD that may otherwise be inapparent. Cytologic evaluation of BAL fluid allows early detection of inflammatory respiratory disease, but it is not specific for COPD. (Am J Vet Res 2001;62: 538–546)

Full access
in American Journal of Veterinary Research

Abstract

Objective—To characterize gelatinases in bronchoalveolar lavage fluid (BALF) and gelatinases produced by alveolar macrophages of healthy calves.

Sample Population—Samples of BALF and alveolar macrophages obtained from 20 healthy 2-month-old calves.

Procedure—BALF was examined by use of gelatin zymography and immunoblotting to detect gelatinases and tissue inhibitor of metalloproteinase (TIMP)-1 and -2. Cultured alveolar macrophages were stimulated with lipopolysaccharide (LPS), and conditioned medium was subjected to zymography. Alveolar macrophage RNA was used for reverse transcriptasepolymerase chain reaction assay of matrix metalloproteinases (MMPs), cyclooxygenase-2, and inducible nitric oxide synthase.

Results—Gelatinolytic activity in BALF was evident at 92 kd (14/20 calves; latent MMP-9) and 72 kd (18/20; latent MMP-2). Gelatinolytic activity was evident at 82 kd (10/20 calves; active MMP-9) and 62 kd (17/20; active MMP-2). Gelatinases were inhibited by metal chelators but not serine protease inhibitors. Immunoblotting of BALF protein and conditioned medium confirmed the MMP-2 and -9 proteins. Endogenous inhibitors (ie, TIMPs) were detected in BALF from all calves (TIMP-1) or BALF from only 4 calves (TIMP-2). Cultured alveolar macrophages expressed detectable amounts of MMP-9 mRNA but not MMP-2 mRNA.

Conclusions and Clinical Relevance—Healthy calves have detectable amounts of the gelatinases MMP-2 and -9 in BALF. Endogenous inhibitors of MMPs were detected in BALF (ie, TIMP-1, all calves; TIMP-2, 4 calves). Lipopolysaccharide-stimulated alveolar macrophages express MMP-9 but not MMP-2 mRNA. The role of proteases in the pathogenesis of lung injury associated with pneumonia has yet to be determined. (Am J Vet Res 2004;65:163–172)

Full access
in American Journal of Veterinary Research

Abstract

Objective

To determine whether annexins or haptoglobin could be detected in bronchoalveolar lavage (BAL) fluid specimens obtained from calves experimentally inoculated with Pasteurella haemolytica.

Animals

Twelve 2- to 3-month-old male Holstein calves.

Procedure

Pasteurella haemolytica was inoculated into the right lung lobes of each of 6 calves. Six other calves received vehicle alone and were used as control calves. Specimens of BAL fluid were obtained from 3 control and 3 inoculated calves 1 day after inoculation and from the other calves 2 days after inoculation. The amount of annexins I, II, IV, and VI, and haptoglobin in BAL fluid specimens was examined by use of immunoblot analysis.

Results

Annexins I and IV were detected in BAL fluid specimens obtained from the right lung lobes of each of the inoculated calves, but annexins II and VI were not. Annexin I also was found in BAL fluid specimens obtained from the left lung lobes of each inoculated calf and from left and right lung lobes of the control calves. By comparison, detection of annexin IV was essentially limited to the right lung lobes of inoculated calves. Haptoglobin was detected in some, but not all, BAL fluid specimens from the right lung lobes of inoculated calves, and its detection in BAL fluid was associated with serum proteins such as albumin.

Conclusions and Clinical Relevance

Annexin IV was detected most specifically in response to inoculation of P haemolytica. This protein could be used as a marker for inflammatory pulmonary disease caused by P haemolytica. (Am J Vet Res 1999;60:1390–1395)

Free access
in American Journal of Veterinary Research

Abstract

Objectives—To determine the effects of pentoxifylline (PTX) administration on lung function and results of cytologic examination of bronchoalveolar lavage fluid in horses affected by recurrent airway obstruction (RAO).

Animals—10 RAO-affected horses.

Procedures—6 horses were orally administered PTX (16 g) mixed with corn syrup, and 4 horses were administered corn syrup alone, twice daily for 14 days. Pulmonary function was evaluated before administration (day 0) and on days 8 and 15. Bronchoalveolar lavage (BAL) was performed on days 0 and 15. Reversibility of airway obstruction was assessed by measuring pulmonary function before and after administration of atropine (0.02 mg/kg, IV). Serum concentration of PTX was measured in 4 horses 30 minutes and 2 and 4 hours after administration of PTX on days 1, 2, 3, 7, and 14.

Results—Administration of PTX to RAO-affected horses resulted in a decrease in elastance value on day 8 and on elastance and resistance (RL) values on days 8 and 15. Results for cytologic examination of BAL fluid obtained on day 15 did not differ significantly, compared with values for day 0. Values of RL decreased in all horses following administration of atropine. When mixed in corn syrup and administered orally, PTX was poorly absorbed in horses, and there was noticeable variation in serum PTX concentrations over time and among horses.

Conclusions and Clinical Relevance—Based on these results, it can be concluded that administration of PTX at high doses improved respiratory function of RAO-affected horses maintained in an unfavorable environment. (Am J Vet Res 2002;63:459–463)

Full access
in American Journal of Veterinary Research