Efficacy of boric-complexed zinc and acetic-complexed zinc otic preparations for canine yeast otitis externa

The purpose of this 2-week, double-blinded, controlled clinical trial was to evaluate the efficacy of topical amino acid-complexed zinc gluconate formulated with boric acid (ZGB) or acetic acid (ZGA) versus a topical placebo in the treatment of yeast otitis externa in dogs. Included in the study were dogs with otitis externa and a cytopathological finding of yeast organisms in the affected ear. Ears were treated with the placebo, ZGA, or ZGB medications. Yeast counts as well as clinical appearance of the ears were monitored. Results revealed that ZGB significantly reduced the number of yeast organisms in cases of otitis externa.     

Morbidity and mortality associated with a new mycoplasma species from captive American alligators (Alligator mississippiensis).

Nine of 74 American alligators (Alligator mississippiensis) from a captive Florida herd of 3-4-m-long, 200-350-kg, adult males greater than 30 yr of age died within a 10-day period during 1995. Nonspecific clinical signs included anorexia, lethargy, muscle weakness, paraparesis, bilateral white ocular discharge, and various degrees of periocular, facial, cervical, and limb edema. Pneumonia, pericarditis, and arthritis were found on postmortem evaluation of the spontaneously dead and euthanatized alligators. Rapidly growing mycoplasmas were identified by culture, and mycoplasma nucleotide sequences were identified by polymerase chain reaction testing of fresh lung and synovial fluid from an affected alligator. Culture of banked frozen lung from necropsy specimens and fresh lung and fresh synovial fluid from newly affected alligators confirmed the presence of a new mycoplasma species in seven of eight individuals. Oxytetracycline was administered, but related deaths continued for 6 mo until only 14 of the initial alligators remained. An enzyme-linked immunosorbent assay to detect antibody was developed, and the organism was transmitted experimentally to naive juvenile alligators, although the source of the organism, Mycoplasma sp. (ATCC 700619), has not been identified. The alligator isolate is a novel species in the mycoplasma family because its nucleotide sequence does not match those of over 75 characterized mycoplasma species. Such factors as population density, animal age, and mycoplasmal virulence likely contributed to the course of disease.     

A comparison between the effect of an avian reovirus and infectious bursal disease virus on selected aspects of the immune system of the chicken

Reovirus 81-176 was inoculated subcutaneously into day-old specific-pathogen-free leghorns and evaluated for its effects on the immune system over a 3-week period. Structural criteria included organ weights of the bursa of Fabricius (BF) and spleen (SP), scoring of histological lesions in the BF, SP, and thymus, and hematological analyses of the circulating leukocytes. Alterations in the functional capacity of the immune system were measured using the graft-versus-host reaction, the response of peripheral blood lymphocytes (PBLs) to mitogens, the ability of circulating monocytes to phagocytize latex beads, and the serological responses to Newcastle disease virus, sheep red blood cells, and Brucella abortus antigens. For comparison, infectious bursal disease virus (IBDV) was similarly evaluated by most of the same tests. Structurally, reovirus 81-176 altered BF and SP organ weights, the total numbers of white blood cells in circulation, and the degree of follicular atrophy in the BF. Functionally, reovirus inoculation reduced both the response of PBLs to the phytohemagglutinin-P stimulation and monocyte uptake of latex beads. According to the protocols used here, no significant alteration in B-cell function could be detected in reovirus-infected chicks. With the exception of leukocyte hematology, IBDV-infected chicks had significantly altered responses in all tests used. By way of comparison, the effects of IBDV were more persistent and pronounced than were those seen with reovirus. The graft-versus-host reaction indicated an elevated and/or uninhibited response of T-cells in the blood of IBDV-infected chicks.     

Detection of infectious bursal disease virus in experimentally infected chickens by in situ hybridization

In situ hybridization was used in a pathogenesis study of three vaccine pathotypes (Delaware variant A, D78, and BursaVac) of infectious bursal disease virus (IBDV). Tissues were excised (bursa, thymus, spleen, proventriculus, and cecal tonsils), fixed in formalin, and paraffin embedded at 12, 24, 48, 72, and 120 hr postinoculation (HPI). With an antisense VP2 gene probe, viral nucleic acid was detected in bursas from both D78- and BursaVac-infected chickens at 24, 48, 72, and 120 HPI. However, viral RNA was detected only in the Delaware variant A-infected birds at 72 HPI. Thymus and spleen were positive in the D78-infected birds at 48 HPI and in the BursaVac-inoculated group at 72 HPI. Viral nucleic acid was not present in detectable levels among any of the tissues tested at 12 HPI. However, by 24 hr, scattered positive lymphoid cells were visualized in the bursal follicles of chickens infected with D78 and BursaVac. In addition, low levels of viral nucleic acids were detected in the thymus and spleen among the D78- and BursaVac-infected birds. The sites of viral replication were consistent between the two vaccine-infected groups (D78 and BursaVac), whereas the chickens infected with Delaware variant A had limited IBDV replication in the bursa.     

Effects of the calcium channel antagonist amlodipine in cats with surgically induced hypertensive renal insufficiency

OBJECTIVE: To determine whether amlodipine besylate decreases systemic arterial blood pressure (BP) and reduces the prevalence of complications in cats with induced hypertensive renal insufficiency. ANIMALS: 20 cats with partial nephrectomy. PROCEDURE: Following reduction in renal mass, 10 cats were administered 0.25 mg of amlodipine/kg, PO, q 24 h (group A). Ten cats served as a control group (group C). Systolic BP (SBP), diastolic BP (DBP), and mean BP (MBP), physical activity, and pulse rate were measured continuously for 36 days by use of radiotelemetric devices. RESULTS: Compared with values for clinically normal cats, SBP, DBP, and MBP were significantly increased in cats of group C. Cats in group A had significant reductions in SBP, DBP, and MBP, compared with values for cats in group C. Albuminuria but not urine protein-to-creatinine ratio was significantly correlated (R2 = 0.317) with SBP in hypertensive cats. Prevalence of ocular lesions attributable to systemic hypertension in group C (7 cats) was greater than that observed in group A (2). Two cats in group C were euthanatized on day 16 because of nuerologic complications attributed to systemic hypertension. One normotensive cat in group A was euthanatized because of purulent enteritis of unknown cause on day 27. CONCLUSIONS AND CLINICAL RELEVANCE: Amlodipine had an antihypertensive effect in cats with coexistent systemic hypertension and renal insufficiency. Its use may improve the prognosis for cats with systemic hypertension by decreasing the risk of ocular injury or neurologic complications induced by high BP.     

Activation of bovine peripheral blood gammadelta T cells for cell division and IFN-gamma production

Bovine peripheral blood gammadelta T cells have been evaluated for effector function (IFN-gamma production) and clonal expansion in a variety of systems including following activation by mitogens, IL-12, and stimulation, through the T cell receptor (TCR) with anti-CD3 monoclonal antibody (mAb), a cell-bound molecule and a soluble antigenic extract. To evaluate cell division, carboxyfluorescein succinimidyl ester (CFSE) loading of cells and flow cytometric analysis were used, while IFN-gamma production was evaluated by intracytoplasmic staining. It was found that bovine gammadelta T cells produced IFN-gamma and clonally expanded when stimulated through the TCR/CD3 complex by a cell-associated autologous molecule on monocyte, by bacterial components following in vivo sensitization of gammadelta T cells with a leptospira vaccine or by anti-CD3 mAb. In addition, gammadelta T cells were activated efficiently for effector function but not clonal expansion by culturing with IL-12. In contrast, stimulation by Con A or PMA/ionomycin induced efficient replication but only low level IFN-gamma production which was not enhanced by the presence of IL-12. In several systems the amount of IFN-gamma produced per cell by gammadelta T cells was less than that produced by CD4 T cells in the same cultures.     

Polyomavirus infection in hamsters and trichoepitheliomas/cutaneous adnexal tumours

Multiple skin nodules, with histological features of adnexal tumours consistent with trichoepithelioma, were observed on the head and trunk of Syrian hamsters. Skin biopsies from 20 hamsters from five different colonies were affected, and two of the affected hamsters also had lymphoma. Two owners reported that 16 of 70 hamsters and 50 of 100 hamsters in their colonies had similar skin lesions. These tumours have previously been associated in laboratory colonies with hamster polyomavirus (HaPV) infection. Examination of skin tissues by electron microscopy failed to reveal intranuclear virus particles. Using recombinant major capsid protein VP1 of HaPV, VP1-specific antibodies were detected in sera from 12 of 12 affected hamsters and in four of four unaffected in-contact hamsters, by ELISA. The ELISA data were verified by immunoblot analysis. Eleven of 13 serum samples contained antibodies which reacted with at least one recombinant structural HaPV protein (VP2), including samples from three in-contact unaffected hamsters. Nine of the 11 anti-VP2-positive samples also reacted with recombinant VP3 of HaPV, and six reacted with VP1. Amplification by PCR and sequencing detected VP1 -encoding sequences showing a high degree of homology with HaPV. The findings suggest a possible infection by HaPV or a HaPV-like virus and it is likely that such an infection was enzootic within the affected colonies.     

Evaluation of cystatin C as an endogenous marker of glomerular filtration rate in dogs

Cystatin C is a cysteine protease inhibitor produced by all nucleated cells. It is freely filtered by the glomerulus and is unaffected by nonrenal factors such as inflammation and gender. Because of greater sensitivity and specificity, cystatin C has been proposed to replace creatinine as a marker of glomerular filtration rate (GFR) in humans. The aims of this study were to validate an automated assay in canine plasma and to evaluate the usefulness of cystatin C as a marker of GFR in dogs. Western blotting was used to demonstrate cross-reactivity of an anti-human cystatin C antibody. An immunoturbidimetric assay was used to detect cystatin C in 25 clinically healthy dogs and 25 dogs with renal failure. Mean cystatin C concentration in the healthy dogs and the dogs with renal failure was 1.08 +/- 0.16 mg/L and 4.37 +/- 1.79 mg/L respectively. Intra- and interassay variability was <5%. The assay was linear (r = .974) between 0.14 and 7.53 mg/L. Both cystatin C and creatinine concentrations were measured in banked, frozen serum from 20 remnant kidney model dogs and 10 volume-depleted dogs for which GFR measurements by exogenous creatinine clearance had been determined previously. In the remnant kidney model, cystatin C was better correlated with GFR than creatinine (r = .79 versus .54) but was less well correlated with GFR in volume-depleted dogs (r = .54 versus .95). GFR measurements were repeated in the remnant kidney model dogs 60 days after initial GFR measurements. At this time, cystatin C and creatinine concentrations correlated equally well with GFR (r = .891 versus .894, respectively). Cystatin C concentration is a reasonable alternative to creatinine for screening dogs with decreased GFR due to chronic renal failure.