Epidermal tight junctions (TJ) have been well-described in human medicine and are involved in many skin diseases such as atopic dermatitis (AD). In dogs, there are no data regarding the implication of TJ in skin diseases including canine AD. The aim of this study was to compare the expression and the distribution of ZO-1, occludin and claudin-1 in the epidermis of healthy and atopic dogs. Skin biopsies from 6 high IgE-producing beagles sensitized to house dust mite (atopic group) were used. Skin specimens from nine healthy dogs without skin issues were sampled (healthy group). Immunoperoxydase staining was used to study the staining pattern of zonula occludens-1 (ZO-1), occludin and claudin-1 in the epidermis of healthy and atopic dogs. Positive controls were healthy human skin samples. Labeling patterns were assessed by 2 examiners blinded to the identities of the specimens. Comparisons between groups were performed using an exact Wilcoxon-Mann-Whitney test. The mean total expression score of claudin-1 was lower in atopic dogs as compared to healthy subjects. Occludin and ZO-1 expression remained unchanged within each group. These results suggest a defect in claudin-1 expression in the nonlesional epidermis of atopic dogs.

Meadow voles (Microtus pennsylvanicus) are permissive to chronic wasting disease (CWD) infection, but their susceptibility to other transmissible spongiform encephalopathies (TSEs) is poorly characterized. In this initial study, we intracerebrally challenged 6 meadow voles with 2 isolates of sheep scrapie. Three meadow voles acquired a TSE after the scrapie challenge and an extended incubation period. The glycoform profile of proteinase K-resistant prion protein (PrPres) in scrapie-sick voles remained similar to the sheep inocula, but differed from that of voles clinically affected by CWD. Vacuolization patterns and disease-associated prion protein (PrPSc) deposition were generally similar in all scrapie-affected voles, except in the hippocampus, where PrPSc staining varied markedly among the animals. Our results demonstrate that meadow voles can acquire a TSE after intracerebral scrapie challenge and that this species could therefore prove useful for characterizing scrapie isolates.

The objective of this study was to determine the effect of additional human chorionic gonadotrophin (hCG) on the ovarian response of gilts previously treated with 200 IU hCG combined with 400 IU equine chorionic gonadotrophin (eCG) (eCG/hCG). Seventy-one prepuberal gilts (105 ± 7.5 kg) were assigned to groups: i) eCG/hCG (hCG-0; n = 25); ii) eCG/hCG followed by 100 IU of hCG at 24 h (hCG-100; n = 24); iii) eCG/hCG followed by 200 IU hCG at 24 h (hCG-200; n = 10); and iv) controls (CON; n = 12). Ovulation response was assessed by ovarian dissection or real-time ultrasonography. Additional hCG did not significantly improve numbers of gilts ovulating. Numbers of corpora lutea increased with hCG, and was higher in hCG-200 (P < 0.01). Compared to hCG-0, the frequency of cysts in gilts was higher in hCG-100 (P < 0.05) and further increased in hCG-200 (P < 0.01). The number of cysts per gilt was dose-dependently increased by additional hCG. We conclude that supplemental hCG will increase the number of corpora lutea but will be associated with follicular cyst development in a dose dependent manner.

OBJECTIVE To assess changes in biochemical and biophysical properties of canine RBCs during cold (1° to 6°C) storage in a licensed RBC additive solution (the RBC preservation solution designated AS-1) supplemented with ascorbic acid. SAMPLE Blood samples from 7 neutered male Greyhounds; all dogs had negative results when tested for dog erythrocyte antigen 1.1. PROCEDURES Blood was collected into citrate-phosphate-dextrose and stored in AS-1. Stored RBCs were supplemented with 7.1mM ascorbic acid or with saline (0.9% NaCl) solution (control samples). Several biochemical and biophysical properties of RBCs were measured, including percentage hemolysis, oxygen-hemoglobin equilibrium, and the kinetic rate constants for O2 dissociation, carbon monoxide association, and nitric oxide dioxygenation. RESULTS Greyhound RBCs stored in AS-1 supplemented with ascorbic acid did not have significantly decreased hemolysis, compared with results for the control samples, during the storage period. CONCLUSIONS AND CLINICAL RELEVANCE In this study, ascorbic acid did not reduce hemolysis during storage. Several changes in stored canine RBCs were identified as part of the hypothermic storage lesion.

Mannheimia haemolytica is an important cause of pneumonia in feedlot cattle. Nuclear factor erythroid-2-related factor 2 (Nrf2) is a redox-sensitive transcription factor responsible for the induction of antioxidant enzymes, such as heme oxygenase 1 (HO-1), within the lung. The expression of Nrf2 and HO-1 was immunohistochemically evaluated in 4 calves 24 h after experimental infection with M. haemolytica. Calves receiving normal saline served as controls. In the infected lungs, cytoplasmic Nrf2 expression was high in macrophages and bronchioles and low in alveolar epithelium, whereas nuclear expression was high in endothelial cells, macrophages, and bronchioles and lowest in alveolar epithelium. Normal lung samples displayed only faint Nrf2 cytoplasmic staining within bronchiolar epithelium. Expression of HO-1 was detected within the cytoplasm of macrophages and bronchiolar epithelial cells in all infected lung samples, whereas normal lungs displayed only weak cytoplasmic staining in bronchiolar epithelial cells. These findings suggest that bronchiolar epithelial cells and macrophages up-regulate Nrf2 expression early in the course of infection, which results in increased expression of HO-1 within these cells.

Pododermatitis is a disease of concern for mink breeders in Canada and worldwide, as it causes discomfort and lowers the breeding rates on farms affected by the disease. Unfortunately, the etiology and pathogenesis of pododermatitis are still unknown. In this study, we compared Staphylococcus spp. and Streptococcus canis isolates from healthy mink with isolates from animals with pododermatitis on 2 farms in Ontario. Almost all hemolytic Staphylococcus spp. isolated were shown to be Staphylococcus delphini Group A by 16S ribosomal ribonucleic acid (rRNA) sequence analysis and polymerase chain reaction (PCR). Pulsed-field gel electrophoresis (PFGE) did not reveal any S. delphini or S. canis clonal lineages specifically associated with pododermatitis, which suggests that these bacteria do not act as primary pathogens, but does not dismiss their potential roles as opportunistic pathogens. While S. delphini and S. canis were the most prevalent bacterial pathogens in mink pododermatitis, they were also present in samples from healthy mink. Arcanobacterium phocae is occasionally isolated from pododermatitis cases, but is difficult to recover with conventional culture methods due to its slow growth. A quantitative real-time PCR was developed for the detection of A. phocae and was tested on 138 samples of footpad tissues from 14 farms. The bacterium was detected only in pododermatitis-endemic farms in Canada and was at higher concentrations in tissues from infected footpads than in healthy tissues. This finding suggests that A. phocae is involved in the pathogenesis of pododermatitis.

Indirect enzyme-linked immunosorbent assays (ELISAs) are frequently run as endpoint ELISAs (e-ELISAs). However, kinetic ELISAs (k-ELISAs) have certain advantages over e-ELISAs. The objective of this study was to understand the relationship between e-ELISA and k-ELISA results. Specifically, to determine whether it was possible to run both k-ELISA and e-ELISA on the same plate and establish an appropriate time interval for k-ELISA measurements. A normalization method for k-ELISA slopes (slope ratio) is proposed. Using an indirect e-ELISA test measuring antibodies against Ostertagia ostertagi in milk from dairy cattle, we found that running a k-ELISA had no effect on optical density ratio results of an e-ELISA on the same plate, and that agreement was very strong at 10, 15, and 28 min, allowing for a reduction in the total processing time for ELISA tests.

OBJECTIVE To compare the characteristics and multipotential and in vivo cartilage formation capabilities of porcine adipose-derived stem cells (pASCs) with those of porcine skin-derived stem cell–like cells (pSSCs). ANIMALS Three 6-month-old female pigs and four 6-week-old female athymic mice. PROCEDURES Adipose and skin tissue specimens were obtained from each pig following slaughter and digested to obtain pASCs and pSSCs. For each cell type, flow cytometry and reverse transcription PCR assays were performed to characterize the expression of cell surface and mesenchymal stem cell markers, and in vitro cell cultures were performed to determine the adipogenic, osteogenic, and chondrogenic capabilities. Each cell type was then implanted into athymic mice to determine the extent of in vivo cartilage formation after 6 weeks. RESULTS The cell surface and mesenchymal stem cell marker expression patterns, multipotential capability, and extent of in vivo cartilage formation did not differ significantly between pASCs and pSSCs. CONCLUSIONS AND CLINICAL RELEVANCE Results suggested that pSSCs may be a viable alternative to pASCs as a source of progenitor cells for tissue engineering in regenerative medicine.

OBJECTIVE To compare pursestring, Witzel (seromuscular inversion), and seromuscular incision jejunostomy tube placement techniques in vitro. SAMPLE Jejunal specimens from 10 dogs. PROCEDURES Jejunal segments (50 cm) were harvested immediately prior to euthanasia from 10 mixed-breed dogs Specimens were harvested with the orad and aborad ends clamped and stored in saline (0.9% NaCl) solution–soaked towels during instrumentation. Three jejunostomy tubes were placed via 3 techniques (pursestring, Witzel, and seromuscular incision), and 2 double lumen central venous catheters were placed at each intestinal end for luminal filling and leak testing. Intestinal luminal area was measured ultrasonographically with specimens suspended in a warm undyed saline solution bath with the intestinal lumen filled with dyed saline solution (intraluminal pressure, 6 mm Hg). Leak testing was performed by means of infusion of dyed saline solution (4 mL/min) until each jejunostomy site failed. Intestinal luminal area and leakage pressure were compared between the 3 tube placement techniques. RESULTS The Witzel and seromuscular incision techniques decreased the intestinal luminal area measured at the tube insertion site, albeit nonsignificantly. For the seromuscular incision technique, a significant decrease in intestinal luminal area at the intraluminal site of measurement was found. For 2/30 specimens (1/10 pursestring and 1/10 seromuscular incision), failure occurred at pressures within the range of previously reported peak peristaltic pressure for dogs. Failure occurred at supraphysiologic peristaltic pressures for the remaining 28 specimens, including all 10 specimens for the Witzel technique. CONCLUSIONS AND CLINICAL RELEVANCE In this in vitro study, all specimens for the Witzel technique withstood physiologic peristaltic pressures during leak testing. Both tunneling techniques (Witzel and seromuscular incision) created a decrease in intestinal luminal area. Further investigation, including in vivo testing, is indicated to evaluate the clinical relevance of these findings.

OBJECTIVE To evaluate effects of laser treatment on incisional wound healing in ball pythons (Python regius). ANIMALS 6 healthy adult ball pythons. PROCEDURES Snakes were sedated, a skin biopsy specimen was collected for histologic examination, and eight 2-cm skin incisions were made in each snake; each incision was closed with staples (day 0). Gross evaluation of all incision sites was performed daily for 30 days, and a wound score was assigned. Four incisions of each snake were treated (5 J/cm2 and a wavelength of 980 nm on a continuous wave sequence) by use of a class 4 laser once daily for 7 consecutive days; the other 4 incisions were not treated. Two excisional skin biopsy specimens (1 control and 1 treatment) were collected from each snake on days 2, 7, 14, and 30 and evaluated microscopically. Scores were assigned for total inflammation, degree of fibrosis, and collagen maturity. Generalized linear models were used to investigate the effect of treatment on each variable. RESULTS Wound scores for laser-treated incisions were significantly better than scores for control incisions on day 2 but not at other time points. There were no significant differences in necrosis, fibroplasia, inflammation, granuloma formation, or bacterial contamination between control and treatment groups. Collagen maturity was significantly better for the laser-treated incisions on day 14. CONCLUSIONS AND CLINICAL RELEVANCE Laser treatment resulted in a significant increase in collagen maturity at day 14 but did not otherwise significantly improve healing of skin incisions.