Effect of lenperone hydrochloride on gastroesophageal sphincter pressure in healthy dogs.

Treatment of healthy dogs with the butyrophenone derivative, lenperone hydrochloride, at two different doses significantly decreased gastroesophageal sphincter pressure (GESP). No dose-related effect was identified. Individual variation in the response to lenperone hydrochloride was noted which was consistent on a day-to-day basis. Lenperone hydrochloride is unsuitable for chemical restraint of dogs undergoing esophageal manometry because it decreases GESP and because the magnitude of the decrease varies considerably between dogs.     

Nutrition and the heart

Nutritional deficiencies (e.g., carnitine in dogs, taurine in cats) resulting in cardiomyopathy, and nutritional excesses (e.g., calories leading to obesity, sodium leading to hypertension) have emerged as important considerations in cardiology. These dietary factors may become particularly exaggerated in altered physiological and/or pathological states (e.g., pregnancy, old age, primary cardiovascular disease). Unfortunately, we do not have complete information on requirements for essential nutrients, nor do we know the precise role nutrition may play in the production of so-called old-age diseases or on the interactions among other organ systems (e.g., kidney, liver) and the heart.     

Studies of infectious laryngotracheitis vaccines: immunity in layers

Ten-week-old layer chickens obtained from a commercial source were eye-drop vaccinated with chicken-embryo-origin (CEO) or tissue-culture-origin (TCO) vaccines for infectious laryngotracheitis (ILT). Controls were not vaccinated. Approximately one-third of the layers were challenged with virulent ILT virus at 21, 40, or 60 weeks of age. Serum samples taken from the layers before challenge were used in a virus neutralization (VN) test to determine vaccination titers at those three ages. Both vaccines induced low VN titers (geometric mean titer [GMT] less than 6). At 21 weeks of age, the titers produced by the two vaccines were not significantly different, but at 40 and 60 weeks of age the VN GMT of the CEO-vaccinated group was significantly greater than that of the TCO-vaccinated group. The VN GMTs did not drop over time in either group and actually rose between 21 and 60 weeks of age in the CEO group. Both vaccines protected layers against severe challenge with virulent ILT virus, neither being significantly better than the other under these experimental conditions. Unvaccinated sentinel chickens were maintained in contact with the vaccinated layers during three intervals between 1 day and 6 weeks post-vaccination. Diagnostic tests performed on the sentinels to detect lateral spread of vaccine virus from vaccinated to unvaccinated chickens showed scattered positive results.     

Comparative microscopic lesions in reoviral and staphylococcal tenosynovitis

Experimental inoculation of 1-day-old male broiler chickens with avian reo-virus or Staphylococcus aureus caused tenosynovitis of the gastrocnemius and digital flexor tendons. Reovirus inoculation by either the oral or footpad route initiated a diffuse lymphocytic infiltration in the peritendineum, synovial membrane, and epitenon from 1 to 5 weeks postinoculation (PI). Heterophils were not a predominant feature of the inflammatory response, but when present they were localized with fibrin in and around synovial spaces. The prevalence of microscopic tendon lesions was less common with staphylococcal infection than with reovirus infection. With staphylococcus, lesions were localized to the synovial space and membranes and were characterized by heterophils and fibrin but few lymphocytes. Synovial cell hyperplasia and bursal atrophy were common in both groups. From 10 to 20 weeks PI, both groups developed progressive tendon fibrosis. These results indicate that tenosynovitis due to inoculation with reovirus or staphylococcus may be differentiated histologically from 1 through 5 weeks PI. After 10 weeks, this may not be possible, because diffuse fibrosis was the major lesion with both. Perhaps fibrosis predisposes older, heavier broilers to tendon failure and rupture.     

Canine pythiosis--isolation and identification of Pythium insidiosum

Pythium insidiosum was isolated from the subcutaneous tissue of a 1-year-old tan crossbreed dog and from the intestinal tract of an 18-month-old Samoyed male. Gomori's methenamine silver stain was superior to hematoxylin and eosin in demonstrating the organism in tissue sections. The agent was identified as P. insidiosum by zoospore formation in an aqueous yeast extract solution containing grass blades. Exoantigens produced in culture were shown to be identical to known P. insidiosum antigens by microimmunodiffusion.     

Video-assisted thoracoscopy.

Thoracoscopy is a minimally invasive operative endoscopic procedure designed for visual inspection of the thoracic cavity. The use of small, highly maneuverable, rigid telescopes allows visualization beyond what is possible by standard operative techniques. The use of a small video camera attached to a standard rigid telescope allows the operator and assistants to view a simultaneous, enlarged, and clear image. This article focuses on the basic diagnostic and surgical techniques used in veterinary video-assisted thoracoscopy.     

Cytokine gene expression in ileal tissues of cattle infected with Mycobacterium paratuberculosis

Cytokine gene expression in ileal tissues of cattle infected with Mycobacterium paratuberculosis was evaluated. The effects of infection with M. paratuberculosis on cytokine production may influence immune regulation at the site of colonization, resulting in the chronic inflammatory state associated with the latter stages of this disease. Ileal samples were obtained at necropsy from noninfected control cows (n=8) and clinically infected cows (n=7) and processed for immunohistochemistry and in situ hybridization. Cows infected with M. paratuberculosis were in the latter stages of disease with clinical signs such as weight loss, watery diarrhea, and inappetence. Among cytokines we studied, interleukin-1alpha (IL-1alpha), IL-1beta, IL-6, and interferon-gamma (IFN-gamma) were expressed significantly more in infected animals than in noninfected control animals. The expression of tumor necrosis factor-alpha (TNF-alpha), however, was not different between the two groups of cattle. In addition, immunohistochemical staining demonstrated that the number of resident macrophages in the ileum of infected animals was three times greater than that of noninfected cows. In contrast to this, ileal tissues from noninfected control animals contained 1.5 times more neutrophils than the ileal tissues from cows infected with M. paratuberculosis. These data demonstrate that localized ileal cytokine production is different between cows chronically infected with M. paratuberculosis and noninfected control cows.