Expression of xenobiotic metabolising enzymes in lungs of horses with or without histological evidence of lower airway inflammation.

Mild, moderate and severe equine asthma is a problem for equine welfare. The aetiology of the disease is not known in detail but is likely multi-factorial. One important factor may be inhaled dust which carries harmful substances which may be bioactivated and thus can lead to local inflammation in the airways. The aim of this study was to investigate gene expression and protein localisation of cytochrome P450 (CYP) enzymes, superoxide dismutase and glutathione-S-transferases (GST) involved in bioactivation and detoxification of harmful substances in lungs of horses with or without histological evidence of lower airway inflammation. Significantly lower gene expression of CYP2A13 and GSTM1 was observed in lungs from horses with histological evidence of lower airway inflammation compared with horses without. A higher expression, although not significant, was found for CYP1A1 in horses with histological evidence of lower airway inflammation. There were no differences in gene expression of GSTP1 and SOD3. The proteins were localised in the respiratory epithelium which is of relevance as a defence to local exposure of inhaled harmful substances. In conclusion, our study reports differential gene expression of enzymes involved in bioactivation and detoxification of foreign substances in the lungs of horses with histological evidence of lower airway inflammation compared with horses without.

Malignant acoustic schwannoma in a dog.

A malignant schwannoma of the right acoustic nerve of a dog is described. The neoplasm was found during necropsy of a 12-year-old, spayed, female Labrador Retriever that experienced a sudden onset of severe pain in the neck and upon opening the mouth. Concurrent mild hind limb ataxia also was present. The tumor had infiltrative growth, and the spindle-shaped neoplastic cells were arranged in sheets and concentric whorls. Immunohistochemical staining of the neoplastic spindle cells was positive for S-100 antigen, neuron-specific enolase, and glial fibrillary acidic protein.

Onchocercosis of an intervertebral joint capsule causing cervical vertebral stenotic myelopathy in a horse.

A novel case where onchocercosis was identified as a cause of cervical myelopathy in the horse is described. A 15-year-old Connemara mare was euthanized due to progressive locomotion disturbance. Postmortem examination revealed soft-tissue swelling in the intervertebral joint capsule of C6-7 with narrowing of the vertebral canal. On light microscopy, axonopathy was pronounced in the corresponding segment of the spinal cord. Fibrous tissue and eosinophilic granulomas were found in the joint capsule, together with parasites identified histologically as Onchocerca sp.

Pathological and bacteriological characterization of neonatal porcine diarrhoea of uncertain aetiology.

Neonatal porcine diarrhoea of uncertain aetiology has been reported from a number of countries. This study investigated 50 diarrhoeic and 19 healthy piglets from 10 affected Swedish herds. The piglets were blood-sampled for analysis of serum γ-globulin and necropsied, and the intestines were sampled for histopathology and cultured for Escherichia coli, Clostridium perfringens and Clostridium difficile. Escherichia coli isolates (n = 276) were examined by PCR for virulence genes encoding LT, STa, STb, EAST1, VT2e, F4, F5, F6, F18, F41, AIDA-I, intimin, and for the genes aaiC and aggR. Selected isolates were analysed for additional virulence genes by a microarray and subjected to O-typing. Clostridium perfringens isolates (n = 152) were examined by PCR for genes encoding major toxins, enterotoxin and beta2-toxin. There was no difference in serum γ-globulin concentration between diarrhoeic and non-diarrhoeic piglets, and pathological lesions in the intestines were generally mild. Porcine enterotoxigenic Escherichia coli, a common cause of piglet diarrhoea, was only found in two piglets. Further, the virulence gene profiling did not suggest involvement of other diarrhoeogenic pathotypes of Escherichia coli. Growth of Clostridium perfringens did not differ between diarrhoeic and non-diarrhoeic piglets. All isolates were type A, all were negative for enterotoxin, and 151 of 152 isolates were beta2-toxin positive. In pigs ≥ 2  days old, moderate to profuse growth of Clostridium difficile was more common in the controls. In conclusion, it was not possible to relate Escherichia coli, Clostridium perfringens type A and C or Clostridium difficile to neonatal porcine diarrhoea in any of the investigated herds.

Expression of T helper type 17 (Th17)-associated cytokines and toll-like receptor 4 and their correlation with Foxp3 positive cells in rectal biopsies of horses with clinical signs of inflammatory bowel disease.

Inflammatory bowel disease (IBD) in horses is an idiopathic disorder, encompassing different types of chronic intestinal inflammation. The pathogenesis of the disease remains to be established, but it has been suggested that an imbalance between regulatory T cells (Tregs) and T helper 17 (Th17)-associated cytokines and altered toll-like receptor 4 (TLR4) expression is associated with intestinal inflammation in other species. The aim of the present study was to quantify Tregs in rectal biopsies from horses affected with IBD by immunohistochemistry and to evaluate expression of genes encoding interleukin (IL)-12p40, IL-17A, IL-23p19 and TLR4 by real-time quantitative PCR. Rectal biopsies from 11 healthy horses and 11 horses with clinical signs of IBD, showing inflammation classified as chronic simple proctitis (CSP) or chronic active simple proctitis (CASP), were evaluated. Expression of IL-17A mRNA was greater in horses affected with CASP compared with horses with CSP or healthy horses. In contrast, expression of IL-12p40 was lower in horses with CSP compared with horses with CASP or healthy horses. TLR4 expression was greater in horses with CASP compared with healthy horses. A positive correlation was seen between the numbers of Tregs and expression of IL-17A and IL-23p19. An association was demonstrated between the histopathological pattern of inflammation, cytokine profile and number of infiltrating Tregs. The research findings suggest that Th17 cells are involved in active IBD, possibly through recruitment of neutrophils via IL-17A, in combination with inadequate suppression of the inflammatory response by Tregs.

Experimental swine dysentery: comparison between infection models.

The aim of the present study was to develop a reproducible porcine infection model with Brachyspira hyodysenteriae. The influence of different factors was evaluated, namely, age, a diet containing large quantities of soybean meal, housing and administration of cortisol or antacids. Furthermore, the synergistic effect of additional bacteria (Escherichia coli O141, Bacteroides vulgatus or a mixture of Bacteroides fragilis, a field isolate of Bacteroides and Fusobacterium necrophorum) was studied. Experimental infection resulted in an increase in the serum concentrations of the acute-phase proteins serum amyloid A and haptoglobin and the percentages of neutrophils and monocytes. These alterations were specifically related to haemorrhagic diarrhoea. Inoculation combined with feeding of large quantities of soybean meal and group-housing induced swine dysentery in all experimental animals. If the pigs were fed soybean meal, kept in single pens and circulated between the pens, five out of nine developed disease.

Expression of reference genes and T helper 17 associated cytokine genes in the equine intestinal tract.

There is accumulating evidence for the involvement of pro-inflammatory cytokines associated with a T helper 17 response in intestinal disorders such as inflammatory bowel disease (IBD) in humans. The involvement of interleukin (IL)-17 or IL-23 in equine IBD has not been studied and most gene expression studies in the equine intestine have been limited to the use of a single non-validated reference gene. In this study, expression of the reference gene candidates ß2 microglobulin (ß2M), glyceraldehyde 3-phosphate dehydrogenase (GAPDH), histone H2A type 1, hypoxanthine-guanine phosphoribosyltransferase (HPRT), 60S ribosomal protein L32 (RPL32), succinate dehydrogenase complex subunit A (SDHA) and transferrin receptor 1 protein coding (TFRC)in the equine intestine was evaluated by quantitative PCR. Three to four reference genes were adequate for normalisation of gene expression in the healthy duodenum, mid-jejunum, colon and rectum, although each segment required a unique combination of reference genes. No combination of the evaluated genes was optimal for the caecum and ileum. Another combination of reference genes (GAPDH, HPRT, RPL32 and SDHA) was optimal for normalisation of rectal samples from healthy and IBD-affected horses, indicating that reference genes should be re-evaluated if material from diseased specimens is analysed. Basal expression of IL-12p40, IL-17A and IL-23p19 was detected in each segment, which will enable gene expression studies of these cytokines by relative quantification.

Fatal acute intestinal pseudoobstruction in mice.

Here we describe the epizootiology and pathology of spontaneous, fatal acute intestinal pseudoobstruction that occurred in a mouse colony of 1000 breeding pairs, mainly of the C57Bl/6 strain and free from known pathogenic agents. Most of the mice affected were dams in the second week of lactation. At necropsy, segments of the small intestines were distended with fluid contents. Widespread apoptosis of the villus epithelium of the small intestine and superficial epithelial cells of the large intestine, associated with strong expression of active caspase 3, was a distinctive feature. Necrotic enterocytes, mucosal erosions, and acute mucosal inflammation were prominent in some mice, and morphologic signs of toxemia were generally present. No light microscopic neuronal changes were apparent in the gut, and no etiologic agents were identified. These results indicate that sudden activation of apoptosis in the trophically stimulated gut epithelium during peak lactation was instrumental for the fatal outcome of the condition, but the primary cause of the motility dysfunction of the bowel was not established.

A previously unidentified Chorioptes species infesting outer ear canals of moose (Alces alces): characterization of the mite and the pathology of infestation.

BACKGROUND: During the past decade, Chorioptes mites occupying the outer ear canals have been a common finding at routine necropsies of moose (Alces alces) in Sweden, but neither the taxonomy of the mites nor lesions from the infestation have been investigated. In this study, the mites are characterized by morphological and molecular techniques, and the histopathology of the skin of the outer ear canal is described. METHODS: External auditory meatuses from 53 necropsied moose were examined for the presence of Chorioptes, and samples from outer ear canals were taken for histopathological and microbiological examination. A proportion of the mites from each moose was identified to species. The DNA was extracted from mites from three moose, and their ITS-2 sequences were determined; these sequences were compared phylogenetically to sequences from other Chorioptes taxa. RESULTS: Chorioptes mites were found in 43 (81%) of the 53 moose. The mites had morphological and genetic characteristics distinct from those of C. texanus and C. bovis, the two species generally accepted within the genus. Morphology also did not argue for a diagnosis as C. crewei, C. mydaus or C. panda. On histopathology, lesions were characterized by a hyperplastic perivascular to interstitial dermatitis with epidermal hyperkeratosis and crust formation. Dermal inflammatory infiltrates were composed of mixed T- and B-lymphocytes, plasma cells and macrophages, whereas eosinophils were notably uncommon. Staphylococcus aureus was grown from the infested epidermis of five of 14 examined moose. CONCLUSION: Chorioptes mite infestation was frequently detected in the outer ear canals of moose in Sweden. The mites were evidently pathogenic, being associated with inflammatory lesions of the external auditory meatus. Our studies indicate infestations with a previously undescribed Chorioptes species.

Experimental Schistosomiasis japonica in the pig: immunohistology of the hepatic egg granuloma.

Use of the pig as an animal model in schistosomiasis research is increasing, but knowledge of the porcine immune response to schistosome infection is still very limited. We investigated the immunohistology of different maturation stages of the Schistosoma japonicum egg granuloma in pigs. Liver sections from pigs experimentally infected with S.japonicum for 9, 12 or 21 weeks were examined by immunohistochemistry using a three-step streptavidin-biotin-complex/immunoperoxidase method or a two-step alkaline phosphatase-mediated system. All granulomas showed marked expression of major histocompatibility complex (MHC) class II in epithelioid macrophages and were dominated by T lymphocytes, comprising both CD4+ and CD8+ phenotypes, with consistently higher proportions noted for CD8+ cells. B lymphocytes, as identified by expression of CD21, were confined to lymphoid nodular structures primarily associated with mature granulomas. Early and mature granulomas contained numerous immunoglobulin (Ig)G+ plasma cells. Significant differences in immunohistology related to duration of infection were not observed. The results indicate that all stages of the hepatic S.japonicum egg granuloma in the pig manifests MHC class II-dependent CD4+ T cell activity concomitant with infiltration of CD8+ T cells. B cell activity preceding the effector cell stage appears to occur in granuloma-associated lymphoid nodules, whereas antibody, mainly IgG, is produced within the granuloma.