Development and evaluation of an endoscopic technique permitting rapid visualization of the cardiac region of the porcine stomach.

Our study was designed to ascertain whether a flexible videoscope could be used to efficiently monitor ulcers of the pars esophagea in a large group of grower-finisher swine. Gastroscopy was performed on 2 separate occasions in 32 pigs following anesthesia with intravenous pentobarbital, and ulcers of the pars esophagea were subjectively graded. The pigs were then necropsied. Grades from the second endoscopic examination were compared for agreement with grades derived from gross inspection of the pars esophagea at necropsy, and with grades derived from histopathologic examination of sections of the same region. The pars esophagea was adequately visualized in all endoscopic examinations. The average duration of each examination, from anesthetic induction, was approximately 8 min. Gastroscopy permitted appreciation of a wide range of focal and diffuse superficial and deep ulcerative lesions of the pars esophagea, but failed to unequivocally identify parakeratosis of the pars esophagea. Agreement between endoscopic and subsequent necroscopic and histopathologic gradings of ulcerations was poor. We concluded that the use of a flexible videoscope permitted rapid inspection of the pars esophagea, and was therefore a practical method of experimentally monitoring the progression of spontaneous gastric ulcers in pigs. We also postulated that the poor agreement between endoscopic and postmortem findings occurred because endoscopy was possibly more sensitive at detecting small and superficial ulcerations. However, further studies are needed to verify the accuracy of endoscopic diagnosis of gastric ulcers in the live pig.

Xenogeneic (bovine) peripheral blood leukocytes engrafted into severe combined immunodeficient mice retain primary immune function.

The immune responsiveness of xenogeneic PBL engrafted into SCID mice was investigated using the bovine PBL-reconstituted SCID mouse model system (PBL-SCID-bo). Bovine PBL-reconstitution and B-cell activity were monitored by bovine serum Ig production. Bovine T-cell function was demonstrated by an antigen-specific immune response to bovine transplantation antigens provided by bovine skin allografts. Bovine allograft rejection was clearly evident in > 65% PBL-SCID-bo that received a bovine PBL inoculum either 30 days after bovine skin grafting, or 7-52 days before bovine skin grafting. Bovine allograft rejection was confirmed via histological examination and was characterized primarily by a band of infiltrating bovine lymphocytes at the periphery of the graft and tissue necrosis. A secondary immune response could be elicited if bovine cells in the PBL inoculum were presensitized to Ag from the bovine skin allograft donor. This study is the first to show that bovine cells engrafted in SCID mice after i.p. injection of bovine PBL retain some aspects of immune competency. These results confirm the value of the xenogeneic PBL-reconstituted SCID mouse model in the study of primary immunity.

Compound odontoma in a dog.

Compound odontomas are rare tumors of dental origin. Though benign, their effect as a space occupying lesion can be dramatic. A large compound odontoma in the caudal right mandible of a five and a half month old dog was managed by surgical enucleation of the abnormal tissues. No recurrence was evident 6 months later.

Differences in signs and lesions in sheep and goats with enterotoxemia induced by intraduodenal infusion of Clostridium perfringens type D.

Enterotoxemia was induced in 4 lambs and 4 goat kids by continuous intraduodenal infusion of a whole culture of Clostridium perfringens type D. Clinical signs, hematologic values, biochemical alterations, and postmortem lesions in the lambs and goat kids were compared. The 4 lambs and 4 goat kids died within 25 hours of beginning the infusions. Lesions were not observed in the gastrointestinal tract of the 4 lambs; however, severe hemorrhagic enterocolitis was found in the 4 goat kids. This difference between the lambs and goat kids in the lesions caused by experimentally induced enterotoxemia may explain the discrepancies reported between sheep and goats in clinical signs, response to treatment, and efficacy of vaccination observed in naturally induced enterotoxemia in the 2 species.

Sporadic, severe bronchointerstitial pneumonia of foals.

Bronchointerstitial pneumonia was diagnosed postmortem in 19 foals in a 10 year retrospective study of submissions to a diagnostic center in Ontario. Mean age at death was 2.0 +/- 0.05 (SEM) mo (range five days to four months). Fourteen of 19 were aged from 1.5 to 2.5 mo. Clinically, the disease was generally characterized by sudden onset of fever and increasingly severe dyspnea which developed into respiratory distress before death. Mean length of illness was 7.0 +/- 0.33 days (range 1-21 days). The disease appeared to affect only individual foals on 19 different farms.At postmortem, lungs were typically diffusely red, wet, firm, and failed to collapse. The major lesion recognized histologically was epithelial necrosis of alveoli and terminal bronchioles. Alveolar lumens contained large epithelioid cells, which were probably macrophages, and multinucleated syncytial cells were present in 16 of the 19 lungs. Inflammatory cells were sparse. Intraalveolar fibrin was prominent in all lungs. Bacteriological examination revealed no significant pathogen in 12 animals, but Rhodococcus equi was isolated from seven foals, associated in two animals with extensive abscesses. Viruses were not recovered from eight foals examined.On the basis of the similarity and severity of lesions, the sporadic nature of the disease, and the similar age at onset which appears to coincide with declining maternally-derived immunoglobulins, we speculate that this disease may be the result of a viral infection.

Histopathologic study of uveitis in cats: 139 cases (1978-1988).

Histopathologic findings in 158 globes obtained from 139 cats by enucleation or at necropsy, with histopathologic diagnosis of uveitis, were compared, and morphology was correlated with clinical and/or histopathologic diagnosis. The most common morphologic feature was a lymphocytic-plasmacytic anterior uveal infiltrate that was either diffuse or nodular; specific cause could not be associated with this nongranulomatous anterior uveitis. In decreasing order of frequency, other common causes of uveitis in cats included feline infectious peritonitis; FeLV-associated lymphosarcoma; trauma; and lens-induced uveitis.

Reproduction of edema disease of swine with purified Shiga-like toxin-II variant.

Twenty-one weaned Yorkshire-Landrace pigs were injected intravenously with graded doses of purified Shiga-like toxin-II variant (edema disease toxin). In a preliminary study, three pigs (Nos. 1, 2, 3) were injected with 48, 24, and 12 ng, respectively, of SLT-IIv/kg of body weight. Subsequently, three groups (Nos. 4, 5, 6) of six pigs each were injected with 6, 3, and 1.5 ng, respectively, of SLT-IIv/kg of body weight. Severe clinical signs and histologic lesions characteristic of edema disease developed in pigs Nos. 1, 2, and 3, and all six pigs in group No. 4. Eight of these pigs were euthanatized in extremis (mean time to death was 34 hours) and one died of the disease (52 hours). Moderate signs and lesions of edema disease were observed in all pigs in group No. 5, and three pigs were euthanatized (mean time to euthanasia was 42 hours). Mild signs and lesions were observed in three pigs in group No. 6. The most common gross pathologic changes were edema of the eyelids, submucosa of the stomach, and mesentery of the spiral colon and hemorrhage of the colon and cerebellum. Microscopic lesions were associated with vascular injury and included vessel necrosis, perivascular edema and hemorrhage, and superficial colonic and cecal erosions. The vascular lesions were observed in the cerebellar folia, submucosa and mucosa of the stomach, cecum, colon, and sporadically in the retina. None of the clinical signs associated with endotoxin were observed.

Tail tip necrosis in Ontario beef feedlot cattle.

Studies were performed to establish the prevalence and importance of tail tip necrosis in the southern Ontario beef feedlot industry and to characterize the gross appearance and histopathology of the condition. In a mail survey, 96% of 71 feedlots with slatted floors, but only 5% of 184 feedlots with solid floors, reported a problem with tail tip necrosis from 1982-1986. Treatments reported included antibiotics, amputation of the tail (therapeutic or preventive), and slaughter. Lameness was associated with tail tip necrosis.A scoring system for severity of necrosis was developed. Repeated inspections revealed that mild lesions were unlikely to progress to more severe stages. Histological alterations such as perivascular edema and hemorrhage, dermal scarring, follicular atrophy, and paucity of leukocytes were compatible with cutaneous ischemia.Of 441 tails inspected at slaughter plants, 34.5% were affected, with 3.4% involving skin lacerations and infection, and 4.3% amputated before slaughter.

The effect of leukotriene B4, leukotriene C4, zymosan activated serum, histamine, tabanid extract and N-formyl-methionyl-leucyl-phenylalanine on the in vitro migration of equine eosinophils.

The migration of equine eosinophils under agarose in response to inflammatory mediators, an arthropod extract and a synthetic peptide was examined. A chemotactic index (CI) was calculated by determining the ratio of the distance of eosinophil migration towards the chemoattractant to the distance migrated towards a buffer. Differences between the CI of those eosinophils exposed to chemoattractants and those exposed only to buffer were assessed by an analysis of variance. All agents except leukotriene C4 and the buffer induced statistically significant directional migration of eosinophils. Leukotriene B4 (LTB4) was the most effective chemotaxin for equine eosinophils. Migration of eosinophils stimulated by 10(-9) M LTB4 exceeded that induced by concentrations of histamine six orders of magnitude greater. The response of equine eosinophils to inflammatory mediators was similar to the reported behavior of human eosinophils. The ability of tabanid extract to attract equine eosinophils suggests that arthropod induced tissue eosinophilia many not depend entirely upon immunological mechanisms. The peptide, N-formyl-methionyl-leucyl-phenylalanine attracted equine eosinophils at 10(-4) M and 10(-3) M, concentrations that exceed those reported to be stimulatory for eosinophils of other species. The results of this study indicate that equine eosinophils are capable of migrating towards diverse stimuli, of which LTB4 was the most effective. It is plausible that LTB4 figures prominently in equine inflammation, particularly in lesions dominated by eosinophils.

The causes of glaucoma in cats.

The cause of glaucoma in 131 enucleated eyes from 128 cats was determined in a retrospective histologic study. Obliteration of the ciliary cleft by diffuse iridal melanoma (38 eyes), or other neoplasms (14 eyes), or by the presence of idiopathic lymphocytic-plasmacytic anterior uveitis (53 eyes) were the most frequent lesions likely to explain the development of glaucoma. Secondary changes of inner retinal atrophy, optic disc cupping, scleral thinning with megaglobus, and atrophy of ciliary processes were similar to those described in dogs and human beings with chronic glaucoma. In light of the duration and severity of the glaucoma, the degree of inner retinal atrophy was often less than expected. Diffuse corneal edema and breaks in Descemet's membrane, changes typical of glaucoma in other species, were rarely detected. Eyes with chronic uveitis and glaucoma had collapsed ciliary clefts, iridoscleral adhesions, and posterior displacement of the iris. We were unable to determine whether these changes were consequences of the uveitis and thus responsible for the development of glaucoma, or if they were merely the result of the chronic glaucoma itself.

The pathogenesis and significance of pre-iridal fibrovascular membrane in domestic animals.

Histologic examination was made of 1,419 globes from domestic animals (964 dogs, 374 cats, 41 horses, and 40 cattle) with ocular disease; pre-iridal membranes (rubeosis iridis) were found in 98. The membranes originated as endothelial budding from the anterior iridal stroma and seemed to mature into fibrous or fibrovascular membranes that were often followed by hyphema or, occasionally, glaucoma. Pre-existent disease in the 98 affected globes included chronic endophthalmitis (27/98), chronic glaucoma (24/98), anterior uveal melanoma (15/98), ciliary body adenoma (14/98), neoplasms metastatic to the eye (8/98), and chronic retinal detachment (6/98). In terms of likelihood of occurrence, pre-iridal membranes seen in 21% (6/21) of globes with retinal detachment, 19% (14/75) of those with ciliary body adenomas, 14% (24/167) of those with chronic glaucoma, and 10% (15/158) of those with anterior uveal melanoma. They were detected with greatest relative frequency in horses (9/41) followed by dogs (83/964), cats (5/374) and cattle (1/40). These membranes, which are rarely detected by clinical examination, probably form in response to angiogenic factors released by ischemic retina, by neoplasms, or by leukocytes involved in ocular inflammation.

Cerebrospinal fluid analysis and clinical outcome of eight dogs with eosinophilic meningoencephalomyelitis.

Eight dogs, 14 weeks to 5.5 years of age, had signs of diffuse or multifocal meningoencephalomyelitis. The total white cell counts of the cerebrospinal fluid (CSF) ranged from 11 to 5,550 cells/microliters; the percentage of eosinophils ranged from 21% to 98%. The total CSF protein content range was 19 to 1,430 mg/dl. On necropsy, two dogs had granulomatous encephalomyelitis due to protozoan infection. The other six dogs, of which three were Golden Retriever dogs, appeared to have an idiopathic eosinophilic meningoencephalitis; four of these dogs recovered. The significance of eosinophils in CSF and the possible emergence of a new encephalitic syndrome of dogs involving a hypersensitivity to an unknown agent is also discussed.

Effects of Escherichia coli Shiga-like toxins (verotoxins) in pigs.

Escherichia coli K12 strains TB1(pCG5), with the genes for Shiga-like toxin IIv from an edema disease isolate of E. coli and TB1(pCG5-1), with the toxin genes inactivated by transposon mutagenesis, were used to test the hypothesis that Shiga-like toxin IIv was the same as edema disease principle. Ammonium sulfate precipitated culture supernatants from the pair of E. coli K12 strains and from a wild edema disease isolate of E. coli (E145) were tested for their ability to induce signs and lesions of edema disease in intravenously inoculated weaned pigs. Similar preparations from E. coli which produce Shiga-like toxins I and II were also tested. Preparations from E. coli TB1 (pCG5) and E145 contained high levels of Shiga-like toxin IIv and induced signs and lesions similar to those seen in edema disease, whereas preparations from E. coli TB1 (pCG5-1) failed to induce signs or lesions of edema disease. All Shiga-like toxin preparations produced delayed neurological signs, fibrinoid necrosis of arterioles and hemorrhages in the cerebellum of pigs. High doses of Shiga-like toxin IIv were associated with superficial necrosis of the colonic epithelium and vasculitis. Shiga-like toxins I and II resulted in kidney lesions but no enteric pathology. Shiga-like toxin II preparations had the lowest median lethal dose for pigs, Shiga-like toxin IIv was intermediate and Shiga-like toxin I was the least toxic.

The pathology of lens-induced uveitis in dogs.

Rupture of the lens capsule in 20 dogs resulted in zonal, perilenticular inflammation that did not respond to symptomatic therapy and resulted in the loss of the globe. The reaction was dominated by lens epithelial proliferation, pupillary occlusion, and glaucoma in 11 of the 20. This reaction, herein named phacoclastic uveitis, is unique and easily distinguished from the mild lymphocytic-plasmacytic anterior uveitis that accompanies leakage of lens material through an intact capsule of a hypermature cataract (phacolytic uveitis). None of the dog eyes had the granulomatous perilenticular inflammation that is the hallmark of lens-induced (phacoanaphylactic) uveitis in humans.