Porcine IgE in the context of experimental food allergy: purification and isotype-specific antibodies

Measurement of allergen-specific immunoglobulin E (IgE) is a common practice in the investigation of allergy. It has not been possible to measure porcine IgE due to unavailability of anti-porcine IgE. This study was undertaken to purify and characterize porcine IgE from sera of allergic pigs, identify heterologous anti-IgE reactive with pig IgE and to use purified heavy (H) chain of porcine IgE to generate rabbit anti-IgE. A four-step process for the purification of porcine IgE is reported using ammonium sulphate precipitation, Protein G affinity chromatography, DEAE cellulose anion-exchange chromatography and sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) to obtain IgE H chain. The resultant IgE was evaluated for purity using SDS-PAGE and immunoreactivity was detected by Prausnitz-Küstner (PK) tests and passive cutaneous anaphylaxis with the allergen, crude peanut extract, used to induce experimental allergy. Cross-reactivity with anti-mouse and anti-human IgE antibodies were confirmed in western blot and enzyme-linked immunosorbent assays (ELISA). The H chain of IgE was excised from SDS-PAGE gels and used to develop rabbit anti-porcine IgE antisera. Antiserum obtained from rabbits immunized with porcine IgE, as well as heterologous murine and human-specific anti-IgE, induced reverse cutaneous anaphylaxis in pig skin and detected allergen-specific IgE in ELISA but did not react with IgG H chain in western blots. These results confirm allergy-associated bioactivity of porcine IgE and describe both homologous and heterologous anti-pig IgE suitable for use in allergen-specific and other assays. This will enhance utility of pig allergy models and provide an additional measure of type-2 immune response in pigs.     

Transplacental toxoplasmosis in a wild southern sea otter (Enhydra lutris nereis)

In September 2004, a neonatal sea otter pup was found alive on the beach in northern Monterey Bay, CA. Efforts to locate the mother were unsuccessful. Due to a poor prognosis for successful rehabilitation, the pup was euthanized. Postmortem examination revealed emaciation, systemic lymphadenopathy and a malformation of the left cerebral temporal lobe. On histopathology, free tachyzoites and tissue cysts compatible with Toxoplasma gondii were observed in the brain, heart, thymus, liver, lymph nodes and peri-umbilical adipose. The presence of T. gondii within host tissues was associated with lymphoplasmacytic inflammation and tissue necrosis. Immunofluorescent antibody tests using postmortem serum were positive for anti-T. gondii IgM and IgG (at 1:320 and 1:1280 serum dilution, respectively), but were negative for IgG directed against Sarcocystis neurona and Neospora caninum (<1:40 each). Brain immunohistochemistry revealed positive staining for tachyzoites and tissue cysts using antiserum raised to T. gondii, but not S. neurona or N. caninum. T. gondii parasite DNA was obtained from extracts of brain and muscle by PCR amplification using the diagnostic B1 locus. Restriction enzyme digestion followed by gel electrophoresis and DNA sequencing confirmed the presence of Type X T. gondii, the strain identified in the majority of southern sea otter infections.     

Evaluation of biomarkers of kidney injury following 4% succinylated gelatin and 6% hydroxyethyl starch 130/0.4 administration in a canine hemorrhagic shock model

Objective : To investigate the association between synthetic colloids and biomarkers of acute kidney injury (AKI) in dogs with hemorrhagic shock. Design : Experimental interventional study. Setting : University. Animals : Twenty‐four healthy ex‐racing Greyhounds. Interventions : Anesthetized Greyhounds subjected to hemorrhage for 60 min were resuscitated with 20 mL/kg of fresh whole blood (FWB), 6% hydroxyethyl starch (HES) 130/0.4, 4% succinylated gelatin (GELO), or 80 mL/kg of isotonic crystalloid (CRYST) over 20 min (n = 6 per treatment). Concentrations of biomarkers of AKI were measured at baseline, end of hemorrhage, and at 40 (T60), 100 (T120), and 160 (T180) min after fluid bolus. Biomarkers included neutrophil gelatinase‐associated lipocalin in urine and serum (uNGAL; sNGAL), and urine cystatin C (uCYSC), kidney injury molecule‐1 (uKIM), clusterin (uCLUST), osteopontin, gamma‐glutamyl transferase, monocyte chemoattractant protein‐1 (uMCP), interleukin‐6, interleukin‐8, protein (uPROT), hyaluronan, and F₂‐isoprostanes. Renal histology was scored for tubular injury and microvesiculation. Biomarker fold‐change from baseline was compared between groups using mixed effects models (Bonferroni–Holm corrected P<0.05). Frequencies of histology scores were compared by Fisher's exact test. Measurements and main results : In dogs treated with GELO, uNGAL fold‐change was markedly greater compared with all other groups at T60, T120, and T180 (all P<0.001), and uCYSC was greater at T60 compared with CRYST (P<0.001), and at T120 and T180 compared with all other groups (all P<0.001). Smaller, albeit significant, between‐group differences in uKIM, uCLUST, uMCP, and urine protein concentration were observed across the FWB, GELO, and HES groups, compared with CRYST. The GELO group more frequently had marked tubular microvesiculation than the other groups (P = 0.015) although tubular injury scores were comparable. Conclusion : In dogs with hemorrhagic shock, GELO was associated with greater magnitude increases in urine biomarkers of AKI and more frequent marked tubular microvesiculation, compared with FWB, CRYST, and HES.     

Prevalence of Coxiella burnetii DNA in vaginal and uterine samples from healthy cats of north-central Colorado

Q fever is a worldwide zoonotic disease caused by Coxiella burnetii. Although traditionally associated with livestock exposure, human infection has also been documented from contact with parturient cats. The goal of this study was to determine the prevalence of C burnetii DNA in uterine and vaginal tissues from healthy client-owned and shelter cats of north-central Colorado using polymerase chain reaction assay. Coxiella burnetii was not amplified from vaginal samples of any cat or uterine biopsies of shelter cats. However, a nucleotide sequence with 99% homology to C burnetii DNA was amplified from four of 47 (8.5%) uterine biopsies of client-owned cats. This study demonstrates that clinically normal cats in north-central Colorado can harbor C burnetii. Care should be taken when attending to parturient cats and contact with parturient secretions should be avoided. Additional studies are indicated to further characterize the role of cats in zoonotic Q fever.     

Effects of reconcile (fluoxetine) chewable tablets plus behavior management for canine separation anxiety

Canine separation anxiety is a common behavioral problem presented to veterinarians. Associated behaviors are distressing to both dog and owner, have the potential to disrupt the human-companion animal bond, and may lead to euthanasia. The results of this study demonstrate the clinical efficacy and safety of Reconcile (fluoxetine, 1 to 2 mg/kg/day [0.45 to 0.91 mg/lb/day]), in conjunction with behavior management, for the treatment of canine separation anxiety. The beef flavored chewable formulation was palatable to treated dogs and easy to administer. This study provides to veterinarians and owners valuable information about an effective separation anxiety treatment plan that combines use of Reconcile with behavior modification.     

REVERSIBLE MAGNETIC RESONANCE IMAGING ABNORMALITIES IN DOGS FOLLOWING SEIZURES

Reversible magnetic resonance (MR) imaging lesions have been described in humans following seizures. This condition has not yet been reported in animals. This paper describes reversible abnormalities identified in 3 dogs using MR imaging that was performed initially within 14 days of the last seizure and follow-up imaging that was performed after 10 to 16 weeks of anticonvulsant therapy. All three dogs had lesions in the piriform/temporal lobes, characterized by varying degrees of hyperintensity on T2-weighted images and hypointensity on T1-weighted images. In one dog, contrast enhancement was evident. On reevaluation, partial resolution occurred in all 3 dogs. In a fourth animal with an olfactory meningioma, similar appearing lesions in the temporal cortex and right and left piriform lobes were identified after seizure activity. A surgical biopsy of the temporal cortex and hippocampus was performed and edema, neovascularization, reactive astrocytosis, and acute neuronal necrosis were evident. These histologic findings are similar to those reported in humans with seizures. Recognizing the potential occurrence of reversible abnormalities in MR images is important in developing a diagnostic and therapeutic plan in canine patients with seizures. Repeat imaging after seizure control may help differentiate between seizure-induced changes and primary multifocal parenchymal abnormalities.