Tracheostomy in cats: 23 cases (1998-2006)

Tracheostomies can be used to provide a patent airway in animals with upper airway obstruction but have been reported to be more difficult to manage in cats than in other animals. The purpose of this study is to retrospectively describe the indications, complications and outcome of cats undergoing tracheostomy. Twenty-three cats underwent tracheostomy for laryngeal mass (n=13), trauma (n=5) and upper airway swelling (n=5). Major and minor complications were recorded in 10 and 17 cats, respectively. Seventeen cats were discharged to home, four cats were euthanased and two cats died in hospital. Complications with stoma healing were reported in one cat. Of seven cats discharged with a permanent tracheostomy, one cat is alive and six cats survived at home for between 2 and 281 days. Although complications are common, temporary tracheostomies can be beneficial for conditions in which the underlying cause can be treated. Despite risk of occlusion, permanent tracheostomies can be effective palliative procedures for cats with severe upper airway disease.     

The effects of two non‐steroidal anti‐inflammatory drugs on the mobility of laying hens with keel bone fractures

ObjectiveInvestigate the effects of administration of meloxicam and carprofen on the mobility of hens with and without keel fractures.Study designWithin each of two experiments a ‘blinded’ randomised cross over design whereby birds received either the test drug (carprofen or meloxicam) or saline.AnimalsTwo groups of Lohman Brown hens with and without keel bone fractures.MethodsThe first group (n = 63) was treated with carprofen 25 mg kg⁻¹ and saline subcutaneously, twice. The second group (n = 40) was treated with meloxicam (5 mg kg⁻¹) and saline subcutaneously. The latency of birds to fly down from perches 50, 100 and 150 cm above the ground was measured after each treatment. Data from experiment 1 and 2 were analysed separately; the effects of drug treatment compared with saline on landing time for birds with and without keel bone fractures were evaluated using MLwiN.ResultsIn both experiments latency to fly down from perches was longer in hens with keel fractures and there was a significant interaction between perch height and fracture status. For carprofen, at the 50 cm, 100 cm and 150 cm perch heights, birds with fractures took (mean ± SD) 2.5 ± 2.9, 6.8 ± 9.7 and 11.5 ± 13.2 seconds respectively to fly down compared with 1.3 ± 0.5, 2.3 ± 1.2 and 4.2 ± 3.1 seconds for birds without fractures. For meloxicam, at the 50 cm, 100 cm and 150 cm perch heights, birds with fractures took 2.9 ± 2.5, 49.8 ± 85.4 and 100.3 ± 123.6 seconds respectively compared with 0.7 ± 0.5, 2.5 ± 7.1 and 3.0 ± 4.6 seconds to fly down for birds without fractures. There was no significant effect of carprofen or meloxicam treatment.Conclusion and clinical relevanceThese data provide further confirmation that keel fractures reduce the willingness of birds to move from perches.     

The anesthetic interaction of propofol and sevoflurane on the minimum alveolar concentration preventing motor movement (MACNM) in dogs

The objective of this study was to determine the effects of propofol on the minimum alveolar concentration of sevoflurane needed to prevent motor movement (MAC_NM) in dogs subjected to a noxious stimulus using randomized crossover design. Six, healthy, adult beagles (9.2 ± 1.3 kg) were used. Dogs were anesthetized with sevoflurane on 3 occasions, at weekly intervals, and baseline MAC_NM (MAC_NM-B) was determined on each occasion. Propofol treatments were administered as loading dose (LD) and constant rate infusion (CRI) as follows: Treatment 1 (T1) was 2 mg/kg body weight (BW) and 4.5 mg/kg BW per hour; T2 was 4 mg/kg BW and 9 mg/kg BW per hour; T3 was 8 mg/kg BW and 18 mg/kg BW per hour, respectively. Treatment MAC_NM (MAC_NM-T) determination was initiated 60 min after the start of the CRI. Two venous blood samples were collected and combined at each MAC_NM-T determination for measurement of blood propofol concentration using high-performance liquid chromatography method (HPLC). Data were analyzed using a mixed-model ANOVA and are presented as least square means (LSM) ± standard error of means (SEM).Propofol infusions in the range of 4.5 to 18 mg/kg BW per hour resulted in mean blood concentrations between 1.3 and 4.4 μg/mL, and decreased (P < 0.05) sevoflurane MAC_NM in a concentration-dependent manner. The percentage decrease in MAC_NM was 20.5%, 43.0%, and 68.3%, with corresponding blood propofol concentrations of 1.3 ± 0.3 μg/mL, 2.5 ± 0.3 μg/mL, and 4.4 ± 0.3 μg/mL, for T1, T2, and T3, respectively. Venous blood propofol concentrations were strongly correlated (r = 0.855, P < 0.0001) with the decrease in MAC_NM. In dogs, propofol decreased the sevoflurane MAC_NM in a concentration-dependent manner.     

DNA vaccines encoding the envelope protein of West Nile virus lineages 1 or 2 administered intramuscularly,via electroporation and with recombinant virus protein induce partial protection in large falcons (Falco spp.)

As West Nile virus (WNV) can cause lethal diseases in raptors, a vaccination prophylaxis of free-living and captive populations is desirable. In the absence of vaccines approved for birds, equine vaccines have been used in falcons, but full protection against WNV infection was not achieved. Therefore, two DNA vaccines encoding the ectodomain of the envelope protein of WNV lineages 1 and 2, respectively, were evaluated in 28 large falcons. Four different vaccination protocols were used, including electroporation and booster-injections of recombinant WNV domain III protein, before challenge with the live WNV lineage 1 strain NY99. Drug safety, plasmid shedding and antibody production were monitored during the vaccination period. Serological, virological, histological, immunohistochemical and molecular biological investigations were performed during the challenge trials. Antibody response following vaccination was low overall and lasted for a maximum of three weeks. Plasmid shedding was not detected at any time. Viremia, mortality and levels, but not duration, of oral virus shedding were reduced in all of the groups during the challenge trial compared to the non-vaccinated control group. Likewise, clinical scoring, levels of cloacal virus shedding and viral load in organs were significantly reduced in three vaccination groups. Histopathological findings associated with WNV infections (meningo-encephalitis, myocarditis, and arteritis) were present in all groups, but immunohistochemical detection of the viral antigen was reduced. In conclusion, the vaccines can be used safely in falcons to reduce mortality and clinical signs and to lower the risk of virus transmission due to decreased levels of virus shedding and viremia, but full protection was not achieved in all groups.     

Development of Highly Selective Kv1.3-Blocking Peptides Based on the Sea Anemone Peptide ShK

ShK, from the sea anemone Stichodactyla helianthus, is a 35-residue disulfide-rich peptide that blocks the voltage-gated potassium channel Kv1.3 at ca. 10 pM and the related channel Kv1.1 at ca. 16 pM. We developed an analog of this peptide, ShK-186, which is currently in Phase 1b-2a clinical trials for the treatment of autoimmune diseases such as multiple sclerosis and rheumatoid arthritis. While ShK-186 displays a >100-fold improvement in selectivity for Kv1.3 over Kv1.1 compared with ShK, there is considerable interest in developing peptides with an even greater selectivity ratio. In this report, we describe several variants of ShK that incorporate p-phophono-phenylalanine at the N-terminus coupled with internal substitutions at Gln16 and Met21. In addition, we also explored the combinatorial effects of these internal substitutions with an alanine extension at the C-terminus. Their selectivity was determined by patch-clamp electrophysiology on Kv1.3 and Kv1.1 channels stably expressed in mouse fibroblasts. The peptides with an alanine extension blocked Kv1.3 at low pM concentrations and exhibited up to 2250-fold selectivity for Kv1.3 over Kv1.1. Analogs that incorporates p-phosphono-phenylalanine at the N-terminus blocked Kv1.3 with IC₅₀s in the low pM range and did not affect Kv1.1 at concentrations up to 100 nM, displaying a selectivity enhancement of >10,000-fold for Kv1.3 over Kv1.1. Other potentially important Kv channels such as Kv1.4 and Kv1.6 were only partially blocked at 100 nM concentrations of each of the ShK analogs.