OBJECTIVE To evaluate the effects of successive large-segment tracheal resection and anastomosis on tracheal diameter and position of lobar bronchi in dogs.
ANIMALS 5 adult Beagles.
PROCEDURES Right lateral radiographs were obtained for all dogs and used to measure tracheal length. Dogs were then euthanized, and successive segmental tracheal resections (intervals of 10% from 20% to 50% of the tracheal length), each of which was followed by anastomosis, were performed in each cadaver. Tracheobronchoscopy was performed before the first tracheal resection and after each of the anastomoses to evaluate tracheal diameter and changes in position of lobar bronchi.
RESULTS Tracheal diameter was minimally affected by resections up to 50% of the tracheal length. Diameter of the trachea and position of bronchi were not affected by resection of 20% of the tracheal length. Changes in the position of various lobar bronchi were detected after resection of 30% of the tracheal length.
CONCLUSIONS AND CLINCIAL RELEVANCE In this study, tracheal resections of 20% of the tracheal length were accommodated, possibly as a result of stretching of the annular ligament. Resections of ≥ 30% of the tracheal length altered the position of lobar bronchi. Clinical effects, if any, attributable to these changes in bronchial position remain to be elucidated.
Objective—To develop a high-performance liquid chromatography (HPLC) assay for cetirizine in feline plasma and determine the pharmacokinetics of cetirizine in healthy cats after oral administration of a single dose (5 mg) of cetirizine dihydrochloride.
Animals—9 healthy cats.
Procedures—Heparinized blood samples were collected prior to and 0.5, 1, 2, 4, 6, 8, 10, and 24 hours after oral administration of 5 mg of cetirizine dihydrochloride to each cat (dosage range, 0.6 to 1.4 mg/kg). Plasma was harvested and analyzed by reverse-phase HPLC. Plasma concentrations of cetirizine were analyzed with a compartmental pharmacokinetic model. Protein binding was measured by ultrafiltration with a microcentrifugation system.
Results—No adverse effects were detected after drug administration in the cats. Mean ± SD terminal half-life was 10.06 ± 4.05 hours, and mean peak plasma concentration was 3.30 ± 1.55 μg/mL. Mean volume of distribution and clearance (per fraction absorbed) were 0.24 ± 0.09 L/kg and 0.30 ± 0.09 mL/kg/min, respectively. Mean plasma concentrations were approximately 2.0 μg/mL or higher for 10 hours and were maintained at > 0.72 μg/mL for 24 hours. Protein binding was approximately 88%.
Conclusions and Clinical Relevance—A single dose of cetirizine dihydrochloride (approx 1 mg/kg, which corresponded to approximately 0.87 mg of cetirizine base/kg) was administered orally to cats. It was tolerated well and maintained plasma concentrations higher than those considered effective in humans for 24 hours after dosing. The half-life of cetirizine in cats is compatible with once-daily dosing, and the extent of protein binding is high.
Objective—To evaluate assessment of circulating amino terminal-pro-B-type natriuretic peptide (NT-proBNP) concentration as a means to discriminate between congestive heart failure and primary pulmonary disease in dogs.
Design—Prospective case series.
Animals—46 dogs with signs of respiratory distress or coughing.
Procedures—All dogs underwent physical and thoracic radiographic examinations. Dogs with evidence of heart disease (eg, murmur, arrhythmia, or large cardiac silhouette detected by radiography) also underwent echocardiography. Dogs with no evidence of heart disease or failure were included if they underwent bronchoalveolar lavage (with cytologic examination and bacterial culture of the lavage fluid). Blood samples for NT-proBNP assay were obtained within 12 hours of the diagnosis of heart failure or prior to bronchoalveolar lavage in dogs with primary pulmonary disease. Circulating concentrations of NT-proBNP were compared between groups and correlated with radiographic and echocardiographic measures of cardiac size.
Results—Congestive heart failure and primary pulmonary disease were diagnosed in 25 and 21 dogs, respectively. Dogs with congestive heart failure had significantly higher median serum or plasma NT-proBNP concentration (2,554 pmol/L; interquartile [25% to 75%] range, 1,651.5 to 3,475.5 pmol/L) than dogs with primary pulmonary disease (357 pmol/L; interquartile range, 192.5 to 565.5 pmol/L). Radiographic vertebral heart score and echocardiographic left atrial-to-aortic diameter ratio were not correlated with NT-proBNP concentration. Left ventricular end-diastolic diameter (measured echocardiographically) and NT-proBNP concentration were weakly correlated.
Conclusions and Clinical Relevance—Serum or plasma NT-proBNP concentration assessment may be useful for discrimination of congestive heart failure from primary pulmonary disease in dogs with respiratory distress or cough.
Objective—To determine whether oral administration of cyproheptadine or cetirizine blocks the action of serotonin and histamine, respectively, and results in diminished eosinophilic airway inflammation in cats with experimentally induced asthma.
Animals—9 cats in which asthma was experimentally induced through exposure to Bermuda grass allergen (BGA) during a 3-month period.
Procedures—Cats were randomized to receive monotherapy with each of 3 treatments for 1 week: placebo (flour in a gelatin capsule, PO, q 12 h), cyproheptadine (8 mg, PO, q 12 h), or cetirizine (5 mg, PO, q 12 h). A 1-week washout period was allowed to elapse between treatments. Prior to and following each 1-week treatment period, blood and bronchoalveolar lavage fluid (BALF) samples were collected. The percentage of eosinophils in BALF was evaluated to determine treatment efficacy. Serum and BALF BGA-specific immunoglobulin contents and plasma and BALF histamine concentrations were determined via ELISAs. Plasma and BALF serotonin concentrations were measured by use of a fluorometric method.
Results—The mean ± SD percentage of eosinophils in BALF did not differ significantly among treatment groups (placebo, 40 ± 22%; cyproheptadine, 27 ± 16%; and cetirizine, 31 ± 20%). Among the treatment groups, BGA-specific immunoglobulin content and histamine and serotonin concentrations were not significantly different.
Conclusions and Clinical Relevance—In cats with experimentally induced asthma, cyproheptadine and cetirizine were not effective in decreasing airway eosinophilic inflammation or in altering several other measured immunologic variables. Neither cyproheptadine nor cetirizine can be advocated as monotherapy for cats with allergen-induced asthma.
Objective—To compare concentrations of interleukin (IL)-4, interferon (IFN)-γ, tumor necrosis factor (TNF)-α and total nitric oxide (NO) metabolites in bronchoalveolar lavage fluid (BALF) for discrimination between asthma and chronic bronchitis in cats.
Procedures—Cats screened with cytologic examination of BALF included 13 client-owned cats with naturally developing asthma, 8 client-owned cats with chronic bronchitis, 23 research cats with experimentally induced asthma, 33 research cats with experimentally induced nonseptic suppurative inflammation of the airways, and 20 healthy control cats. Banked unconcentrated BALF supernatant samples were assayed for concentrations of IL-4, IFN-γ, TNF-α, and total NO metabolites.
Results—Concentrations of IL-4 and IFN-γ in BALF were less than the limits of detection for most cats, precluding statistical analysis. No significant differences were detected among groups for TNF-α concentrations. Concentrations of total NO metabolites were significantly higher in cats with clinical chronic bronchitis, compared with research cats with nonseptic suppurative inflammation or research cats with asthma.
Conclusions and Clinical Relevance—There were no significant differences in tested biomarkers between cats with asthma and healthy control cats. None of the measured cytokines or NO metabolites were useful for discriminating between cats with naturally developing asthma and those with chronic bronchitis.
Objective—To compare the effects of an orally administered
corticosteroid (prednisone), an inhaled corticosteroid
(flunisolide), a leukotriene-receptor antagonist
(zafirlukast), an antiserotonergic drug (cyproheptadine),
and a control substance on the asthmatic phenotype
in cats with experimentally induced asthma.
Animals—6 cats with asthma experimentally
induced by the use of Bermuda grass allergen (BGA).
Procedures—A randomized, crossover design was
used to assess changes in the percentage of
eosinophils in bronchoalveolar lavage fluid (BALF); airway
hyperresponsiveness; blood lymphocyte phenotype
determined by use of flow cytometry; and serum
and BALF content of BGA-specific IgE, IgG, and IgA
determined by use of ELISAs.
Results—Mean ± SE eosinophil percentages in BALF
when cats were administered prednisone (5.0 ±
2.3%) and flunisolide (2.5 ± 1.7%) were significantly
lower than for the control treatment (33.7 ± 11.1%).
We did not detect significant differences in airway
hyperresponsiveness or lymphocyte surface markers
among treatments. Content of BGA-specific IgE in
serum was significantly lower when cats were treated
with prednisone (25.5 ± 5.4%), compared with values
for the control treatment (63.6 ± 12.9%); no other
significant differences were observed in content of
BGA-specific immunoglobulins among treatments.
Conclusions and Clinical Relevance—Orally administered
and inhaled corticosteroids decreased
eosinophilic inflammation in airways of cats with
experimentally induced asthma. Only oral administration
of prednisone decreased the content of BGAspecific
IgE in serum; no other significant local or systemic
immunologic effects were detected among
treatments. Inhaled corticosteroids can be considered
as an alternate method for decreasing airway
inflammation in cats with asthma. (Am J Vet Res