Comparison of pulmonary deposition of nebulized 99m technetium-diethylenetriamine-pentaacetic acid through 3 inhalation devices in healthy dogs.

BACKGROUND: Inhalation treatment frequently is used in dogs and cats with chronic respiratory disease. Little is known however about the performance of delivery devices and the distribution of aerosolized drugs in the lower airways. OBJECTIVE: To assess the performance of 3 delivery devices and the impact of variable durations of inhalation on the pulmonary and extrapulmonary deposition of nebulized 99m technetium-diethylenetriamine-pentaacetic acid (99m Tc-DTPA). ANIMALS: Ten university-owned healthy Beagle dogs. METHODS: Prospective crossover study. Dogs inhaled the radiopharmaceutical for 5 minutes either through the Aerodawg spacer with a custom-made nose-muzzle mask, the Aerochamber spacer with the same mask, or the Aerodawg spacer with its original nose mask. In addition, dogs inhaled for 1 and 3 minutes through the second device. Images were obtained by 2-dimensional planar scintigraphy. Radiopharmaceutical uptake was calculated as an absolute value and as a fraction of the registered dose in the whole body. RESULTS: Mean (±SD) lung deposition for the 3 devices was 9.2% (±5.0), 11.4% (±4.9), and 9.3% (±4.6), respectively. Differences were not statistically significant. Uptake in pulmonary and extrapulmonary tissues was significantly lower after 1-minute nebulization, but the mean pulmonary/extrapulmonary deposition ratio (0.38 ± 0.27) was significantly higher than after 5-minute nebulization (0.16 ± 0.1; P = .03). No significant differences were detected after 3- and 5-minute nebulization. CONCLUSION AND CLINICAL IMPORTANCE: The performance of a pediatric spacer with a custom-made mask is comparable to that of a veterinary device. One-minute nebulization provides lower pulmonary uptake but achieves a better pulmonary/extrapulmonary deposition ratio than does 5-minute nebulization.

Acute gastroesophageal intussusception in a juvenile Australian Shepherd dog: endoscopic treatment and long-term follow-up.

BACKGROUND: Canine gastroesophageal intussusception (GEI) is a rare and potentially fatal disease usually affecting puppies or young dogs < 3 months of age and of medium to large breeds. Surgical intervention has been advocated as the therapy of choice by most authors. Endoscopic treatment may offer an advantageous or alternative method of treatment. CASE PRESENTATION: GEI was diagnosed in a nine-week-old Australian Shepherd dog with an acute onset of vomiting and regurgitation and compatible radiographic findings on thoracic radiography. Treatment consisted of endoscopic gastric repositioning and placement of a percutaneous endoscopic gastrostomy (PEG) tube to prevent repeated dislocation of the stomach, and to allow for nutritional supplementation During a follow-up period of eight months, thoracic radiographs were obtained showing persistent esophageal dilatation in the absence of compatible clinical signs. CONCLUSION: Endoscopic intervention is an effective, alternative in selected canine GEI- cases, allowing for rapid, minimally invasive confirmation of diagnosis and therapy. After initial treatment, radiographic long-term follow-up seems prudent even in asymptomatic patients.

Evaluation of variables to describe the shape of volumetric capnography curves during bronchoconstriction in dogs.

The aim of the study was to investigate changes in volumetric capnography (V(C)) variables during bronchoconstriction in dogs and compare it with total respiratory resistance (R(L)) measured with a Fleisch pneumotachograph. Six dogs were challenged with increasing concentrations of carbachol until obvious signs of bronchoconstriction were seen. All V(C) parameters were obtained before, directly after, 10 and 20 min after maximal bronchoconstriction. The slope of phase III (SIII) and airway and alveolar dead space parameters were significantly different from baseline directly after the challenge. The V(C) curve obtained a typical shape at the time of maximal bronchoconstriction and a trend to return to baseline shape was seen over time. A significant correlation was found for all aforementioned parameters with R(L). We conclude that the shape of the V(C) curve in combination with dead space calculation can be used to verify bronchoconstriction on a breath-to-breath basis.

Airway hyperresponsiveness to adenosine 5'-monophosphate in feline chronic inflammatory lower airway disease.

Airway hyperresponsiveness is a key feature of human asthma and chronic bronchitis and response to the indirectly acting agonist adenosine 5'-monophosphate (AMP) is thought to reflect underlying airway inflammation. To examine whether airway responsiveness testing (ART) with AMP may be used to differentiate healthy cats from those with asthma (FA) and chronic bronchitis (CB), 24 cats (9 FA, 6 CB, 9 controls) underwent ART with AMP at concentrations of 0.1, 1, 10, 100 and 500mg/mL using barometric whole body plethysmography. The defined endpoint of ART, an increase in enhanced pause (Penh) exceeding 300% of the post-saline value (baseline), was reached in 9/15 patients (7 FA, 2 CB), but in none of the controls. Mean Penh (±SD) at baseline (BL) was 0.49±0.16 for cases, and 0.54±0.16 for controls, and was significantly increased after AMP challenge in clinical cases (2.62±2.20), but not in controls (0.63±0.30, P<0.05). After separating responder (R) and non-responder (NR) cases, a more pronounced difference after challenge was found (R: 3.96±1.84, NR: 0.6±0.21, P<0.001). The provocative concentration of the agonist that increased Penh to 300% of BL (PC Penh 300) in R cases was 52.98±48.04mg/mL AMP. Age had no influence on the responder status or PC Penh 300. It was concluded that AMP challenge may offer a new method for the identification of cats with lower inflammatory airway disease, and possibly for monitoring disease progression or response to therapy.

Influence of the collection and oxygenation method on quantitative bacterial composition in bronchoalveolar lavage fluid samples from healthy dogs.

The purpose of the study was to evaluate the effects on quantitative and qualitative microbial content of endoscopic bronchoalveolar lavage fluid (BALF) in healthy dogs using a laryngeal mask airway (LMA). It was hypothesised that oropharyngeal protection might prevent contamination of BALF with oropharyngeal microflora. Ten healthy Beagle dogs were randomly assigned to two groups and underwent endoscopic BAL on two occasions, either via an open unprotected oropharynx with oxygen supply provided via a nasal catheter (NT) or through a sterile LMA. For the second sampling, groups were switched. BALF analysis included quantitative microbial culture, nucleated cell counts and cytology. The mean (+/-SD) number of colony forming units (CFU)/mL found in the BALF using the LMA was 25,610+/-22,943 in the right lung (RL) and 22,510+/-18,779 in the left (LL). With the NT technique, the figures were 21,068+/-19,375 for the RL and 16,060+/-15,523 for the LL, respectively. Nucleated cell counts/microL were 691.0+/-181.6 (RL) and 734.0+/-171.6 (LL) for LMA, and 772.0+/-251.0 (RL) and 748+/-163.2 (LL) for NT. No significant differences were detected either in the number of CFU/mL or in the diversity of bacterial species with the two methods. A significant increase in BALF bacterial counts (with reduced species diversity) was observed on the second compared to the first sampling regardless of the method used. Protection of the oral cavity and oropharynx using an LMA had no significant influence on BALF bacterial counts. The findings suggest that with careful endoscope insertion, the risk of contamination of BALF by resident and transient oropharyngeal microflora can be negligible.

Comparison of barometric whole body plethysmography and its derived parameter enhanced pause (PENH) with conventional respiratory mechanics in healthy Beagle dogs.

The purpose of the study was to compare barometric whole body plethysmography (BWBP) and its derived parameter, enhanced pause (PENH), with conventional respiratory mechanics measurements. Resistance (RL), dynamic compliance (Cdyn) and pleural pressure changes were measured in six healthy anaesthetised Beagle dogs using a pneumotachograph and oesophageal balloon technique consecutive to BWBP-derived variables. Upper airway airflow limitation was established (1) by a filter or (2) by insertion of a narrow endotracheal tube. Bronchoconstriction was induced by nebulisation of carbachol at increasing concentrations until PENH exceeded 300% baseline. Upper airway narrowing significantly increased resistance (baseline RL 2.0+/-0.3, RL filter 11.8+/-3.2, RL luminal narrowing 21.1+/-2.3cm H(2)O/L/s; P <0.03), whereas PENH did not change significantly (baseline PENH 0.55+/-0.17, PENH filter 0.49+/-0.10; PENH luminal narrowing 0.50+/-0.18; P >0.05). Carbachol-induced bronchoconstriction caused a significant increase in PENH (baseline PENH 0.43+/-0.14, PENH carbachol 2.62+/-2.14; P <0.02) and resistance (baseline RL 2.1+/-0.3, RL carbachol 28.8+/-13.0 cm H2O/L/s; P <0.01), and a pronounced drop in compliance (baseline Cdyn 163.3+/-73.9, Cdyn carbachol 9.7+/-2.9mL/cmH2O; P <0.02). It was concluded that BWBP detects airflow limitation due to bronchoconstriction but not due to upper airway obstruction in healthy dogs. BWBP represents a valid, although not very sensitive screening tool for respiratory function testing.

Effects of cadmium chloride inhalation on airflow limitation to histamine, carbachol and adenosine 5'-monophosphate assessed by barometric whole body plethysmography in healthy dogs.

The effects of pharmacological bronchoprovocation on airflow patterns and surrogate respiratory parameters assessed by barometric whole body plethysmography (BWBP) were investigated in healthy dogs, previously exposed to cadmium chloride inhalation. BWBP-derived respiratory variables were calculated (1) at baseline and (2) following nebulisation of increasing concentrations of histamine, carbachol and adenosine 5'-monophosphate (AMP) until enhanced pause (PENH) increased to 300% of baseline (PCPENH300). Bronchoalveolar lavage fluid (BALF) cytology before (BCC) and after (ACC) cadmium chloride inhalation revealed cadmium-induced airway inflammation. Neutrophils increased from 6.7 +/- 7.3% (728 +/- 104/microL) BCC to 77.8 +/- 8.6% (3255 +/- 1407/microL) ACC. PCPENH300 for all three agonists significantly decreased ACC (means+/-SD) as follows: PCPENH300(histamine) 0.72 +/- 0.28 mg/mL BCC, and 0.35 +/- 0.31 mg/mL ACC (P<0.02); PCPENH300(carbachol) 0.34 +/- 0.16 mg/mL BCC, and 0.064 +/- 0.032 mg/mL ACC (P<0.02); PCPENH300(AMP) 1000 mg/mL BCC, and 415 +/- 398 mg/mL ACC (P<0.03). The only clinical sign shown was coughing. It was concluded that airway hyperresponsiveness after induced airway inflammation can be determined by BWBP in conscious small sized dogs. BWBP could be a suitable technique to study the respiratory effects of urban environmental pollution in pets.

PCR-based genetic evidence for occurrence of Helicobacter pylori and novel Helicobacter species in the canine gastric mucosa.

The canine gastric mucosa is known to be a habitat for various Helicobacter species. So far, five Helicobacter species have been described from the canine gastric mucosa, but histological studies have demonstrated a greater variety. In order to gain more information on diversity of canine gastric mucosa colonising helicobacters, biopsy samples of four pet dogs were examined by DNA-based techniques. PCR with a primer pair binding specifically to the 16S rDNA of the species of the genus Helicobacter and generating a fragment of approximately 400 bp indicated the presence of Helicobacter strains in the stomachs of the four dogs. PCR products were cloned into Escherichia coli DH10B and PCR-re-amplified 16S rDNA fragments were subjected to amplified ribosomal DNA restriction analysis (ARDRA) employing restriction enzyme HhaI. Restriction profiles indicated the presence of at least two different Helicobacter species in two dogs. Partial sequences of 16S rDNA of six clones were compared with sequences available in the EMBL data bank. Two sequences obtained from different dogs were identical with the corresponding sequences of Helicobacter pylori strains. Three sequences showed highest but moderate similarity values to H. pylori (96.6-98.0%) and one sequence to Helicobacter salomonis (97.3%). In contrast to previous reports our data implicate that the gastric mucosa of dogs may be colonised by strains of H. pylori or a very closely related species but they also confirm indications for the presence of so far uncultivated species of Helicobacter.

Relationship of age, sex, body weight, and hematologic and respiratory variables with airway reactivity in adult cats.

OBJECTIVE: To evaluate the association between airway reactivity and age, sex, body weight, and radiographic findings in cats. ANIMALS: 32 mature cats that constituted 2 age groups (17 young cats that were 1 to 2 years old and 15 old cats that were 12 to 13 years old). PROCEDURE: Cats were placed in the chamber of a barometric whole-body plethysmograph (volume, 38 L), and box pressure was measured at baseline and after aerosol administration of increasing concentrations of carbachol. Airway reactivity was assessed by monitoring increases in enhanced pause (PENH), a unitless variable that measures bronchoconstriction as derived from dose-response curves. The endpoint chosen was the provocative concentration of carbachol that increased PENH to 300% of the baseline value (PCPENH300). RESULTS: We did not find a correlation between PCPENH300 and sex, body weight, number of eosinophils, PENH before bronchoconstriction, respiratory frequency, tidal volume, or minute ventilation. Airway reactivity was significantly less in the old cats (mean +/- SD PCPENH300, 0.578 +/- 0.051%), compared with the value for the young cats (0.053 +/- 0.006%). Radiographic patterns differed significantly between groups of cats; a greater proportion of old cats (12/15) had bronchointerstitial patterns, compared with the proportion of young cats (4/17). CONCLUSIONS AND CLINICAL RELEVANCE: These data support the notion that age exerts a strong influence on airway reactivity in adult cats, and radiographic differences suggest that structural changes in older cats may contribute to this effect. These findings have important implications for interpretation of results of airway reactivity tests in cats.