Ocular examination, including gonioscopy and ultrasonographic biometry (biological measurement), was performed in healthy, purebred Samoyeds. When the dogs were subclassified according to the degree of kinship with cases of primary angle-closure glaucoma, it was found that the opening of the ciliary cleft was wider in dogs less related to dogs with primary angle-closure glaucoma than in more closely related dogs. Furthermore, multivariate analysis of the material indicated that parentage of a dog has a substantial effect on the intraocular distances studied in this investigation (relative depth of the opening of the ciliary cleft, relative corneal thickness, relative anterior chamber depth, relative lens thickness, and relative length of the vitreous body). Finally, heritability of the relative depth of the opening of the ciliary cleft was estimated at 56% and that of the common environmental factor at 19%. The results are indicative of a hereditary component in primary angle-closure glaucoma in the Samoyed breed.

Blood flow to the semitendinosus muscle was studied in 12 dogs after ligation of either the proximal or distal vascular pedicle and elevation of the muscle from its normal position. Using 25-micrometer-diameter radioactive microspheres, flow was measured at rest, h and 18 days after muscle elevation and pedicle ligation. Mean blood flow in the proximal region of the muscle 6 and 18 days after ligation of the caudal gluteal (proximal) pedicle was not significantly different from mean blood flow calculated in the middle and distal regions of the muscle. There was also no significant difference in mean blood flow among proximal, middle, and distal regions of the muscle, 6 and 18 days after ligation of the distal caudal femoral (distal) pedicle. There was significantly (P < 0.05) increased blood flow between group-A (ligation of caudal gluteal artery) and group-C (operated-control) muscles, 6 and 18 days after surgery. There was no loss of muscle fiber striations or nuclei, or presence of fibrous tissue that might have indicated ischemic necrosis in any of the experimental groups. These results indicate that the entire semitendinosus muscle can be sustained by the blood flow from either of its 2 vascular pedicles, which reinforces its potential as a muscle flap.

Vestibulotoxic and ototoxic effects often are seen after long-term, high-dose systemic treatment with gentamicin, but toxic effects after topical use have not been reported in animals, to the authors' knowledge. Vestibular and auditory effects of twice daily otic gentamicin treatment for 21 days were evaluated in 10 dogs with intact tympanic membranes and in the same 10 dogs after experimental bilateral myringotomy. Each dog served as its own control; 7 drops of gentamicin sulfate (3 mg/ml in a buffered aqueous vehicle) were placed in 1 ear, and 7 drops of vehicle were placed in the opposite ear. Treatment and control ears were reversed after myringotomy. Vestibular function was evaluated daily by neurologic examination and behavioral assessment Auditory function was evaluated twice weekly by determination of brain stem auditory evoked potentials. Gentamicin sulfate placed in the ear of clinically normal dogs with intact or ruptured tympanic membranes, in the quantities used in this study, did not induce detectable alteration of cochlear or vestibular function. Serum gentamicin concentration after 21 days of treatment was detectable in only 2 dogs and was an order of magnitude below documented toxic concentrations.

A monoclonal antibody (MAB) against equine tumor necrosis factor-alpha (Eq TNF) was used to investigate the role of TNF in cytokine, eicosanoid, and metabolic responses of Miniature Horses given endotoxin. Plasma concentrations of interleukin 6 (IL-6), lactate, thromboxane A2 metabolite, and prostacyclin metabolite (6-keto-PGF(1 alpha)) were measured in 10 Miniature Horses given 0.25 micrograms of lipopolysaccharide (LPS; Escherichia coli O55:B5)/kg of body weight. Five horses were given Eq TNF MAB and 5 were given isotype-matched MAB as control. All horses were given 1.86 mg of antibody/kg by IV infusion, 5 minutes before LPS was given IV. Blood samples were taken 20 minutes before and at multiple intervals for 24 hours after LPS was given. Interleukin 6 bioactivity in plasma was measured, using IL-6-dependent cell line (B9). Eicosanoid activities were assessed by enzyme immunoassay, and plasma lactate concentration was determined enzymatically. Data were analyzed by ANOVA and Tukey's honest significant difference test for significant (P < 0.05) effect of treatment. Horses given Eq TNF MAB had significantly (P < 0.050) lower peak mean +/- SEM IL-6 (59 +/- 29 U/ml), lactate (16 +/- 2.00 mg/dl), and 6-keto-PGF(1 alpha) (254 +/- 79 pg/ml) values then did horses given control MAB (880 +/- 375 U/ml for IL-6; 26 +/- 0.04 mg/dl for lactate; and 985 +/- 290 pg/ml for 6-keto-PGF(1 alpha)). There was no effect of anti-TNF treatment on LPS-induced thromboxane A2 metabolite production. Tumor necrosis factor mediated IL-6, lactate, and prostacyclin responses, without affecting thromboxane production in horses given LPS.

Release of enzymes from cytoplasmic granules has been postulated to have a major role in neutrophil-mediated tissue injury. Secretion or release of primary granules, specific granules, and cytosolic enzymes by bovine neutrophils was examined by quantifying the release of beta-glucuronidase, B12-binding protein, and lactate dehydrogenase, respectively, in response to predetermined amounts of phorbol myristate acetate, calcium ionophore, and opsonized zymosan. These responses were compared with the enzyme release induced by exposure to live or dead, unopsonized or opsonized Pasteurella haemolytica. The greatest release of beta-glucuronidase, B12-binding protein, and lactate dehydrogenase was observed in neutrophils exposed to live organisms partially because of neutrophil lysis. Bovine neutrophils respond markedly to particulate agonists, live or dead, pathogenic or nonpathogenic, by a selective release of specific granules, an effect enhanced by opsonization. Particulate agonists induce minimal primary granule release other than that induced by cell death. Because bovine neutrophils contain quantitatively high numbers of specific granules, the high rate of secretion/ release in response to P haemolytica organisms could have a major role in the tissue responses that characterize the lesions of pneumonic pasteurellosis.

Levator ani and coccygeus muscle estrogen and androgen receptors were measured in 6, healthy, greater than or equal to 5-year-old, noncastrated, male Beagles (controls) and in 24 dogs with perineal hernia. Estrogen and androgen receptor analyses were performed on levator ani and coccygeus muscle specimens obtained from control dogs at the time of castration; contralateral levator ani and coccygeus muscle specimens were assayed 2 months after castration. During herniorrhaphy of dogs with perineal hernia, levator ani (noncastrated, n = 12; castrated, n = 7) and/or coccygeus (noncastrated, n = 5; castrated, n = 4) muscle biopsy specimens were obtained for estrogen and androgen receptor analyses. For estrogen and androgen receptor assays, each muscle biopsy specimen was homogenized in Tris-EDTA-glycerol buffer, and centrifuged at 30,000 X g; extracts were used for binding with ligands: [3H]methyltrienolone (3H-R1881) for androgen receptors, and [3H]estradiol-17 beta for estrogen receptors. Extracts were incubated overnight at 0 to 4 C. Nonspecific binding was estimated, using 100-fold concentration of cold ligands. Bound and free hormones were separated, using hydroxylapatite batch assay. Receptor numbers for each tissue were calculated as femtomoles (fmol) per milligram of protein. Quantified data were compared between precastration and postcastration controls, using a paired t-test. One-way ANOVA and Bonferroni post-hoc test were used to compare values for precastration controls, postcastration controls, castrated dogs with perineal hernia, and noncastrated dogs with perineal hernia. Significance was set at P < 0.05. Estrogen receptors were not detected. Androgen receptors were characterized by Scatchard analysis (dissociation constant = 3.16 to 6.6 nM R1881, receptor number = 23 to 175 fmol/mg of protein). Post castration controls had significantly higher numbers of androgen receptors in levator ani and coccygeus muscles than did precastration controls. Dogs with perineal hernia (castrated and noncastrated) had lower numbers of androgen receptors than did either control group. The paucity of androgen receptors in pelvic diaphragm muscles of dogs with perineal hernia, compared with controls, suggests that decreases in quantity of androgen receptors contribute to the etiopathogenesis of perineal hernia in dogs.

Restriction endonuclease patterns of genomic fragments separated by use of pulsed-field gel electrophoresis were used to differentiate Brucella abortus strain RB51, a rifampin-resistant mutant of the standard virulent strain 2308, from other brucellae. Results were compared with results obtained by use of standard methods for characterizing brucellae. Electrophoretic patterns of the ATCC type strains allowed identification of the strains to the level of species. Genomic profiles of B abortus biovars 1, 2, and 4 were similar, as were those of biovars 5, 6, and 9. The profile of biovar 3 was similar to that of biovars 5, 6, and 9, except for a missing band at 93 kb and additional bands at 65 and 67 kb. A different fingerprint was detected in B abortus strain RB51, using the pulsed-field gel electrophoresis patterns of genomic DNA digested with restrictive endonuclease Xba I. The profile of B abortus strain RB51 contained a band at 104 kb, as opposed to a 109-kb fragment within profiles of B abortus isolates from naturally infected cattle, bison, and elk. Despite known biochemical and biological differences between RB51 and its parent strain (2308), restriction endonuclease analysis results were similar.

The efficacy of 23 disinfectants (including the most commonly used chemical groups) and 6 quaternary ammonium compound based commercial formulations against Actinobacillus pleuropneumoniae serotype 1 (ATCC 4074) was studied. The organisms were tested in suspension and carrier tests with serum as the organic matter. Chloramine-T, hydrogen peroxide, glutaraldehyde, and mercurochrome alone, and a quatemary ammonium compound formulation containing 10% benzalkonium chloride, 2.5% glutaraldehyde, 6.8% glyoxal, and 6% formaldehyde were effective in all tests, regardless of the presence or absence of organic load. All but 2 of the nonformulated disinfectants (sodium hypochlorite and an iodophor) caused at least a 3-log10 reduction in colony-forming units in the suspension test. However, most of the disinfectants were not as effective in the carrier test as in the suspension test; this difference ranged from a 1- to 5-log10 reduction in colony-forming units. In addition, the presence of serum considerably reduced the disinfectant capacities of most of the compounds tested, particularly in the carrier test. These results indicate the importance of selecting suitable disinfectants for routine use on surfaces contaminated with this organism, especially in the presence of organic matter. Chloramine-T and the aforementioned commercial formulation were also tested directly under field conditions in pig nurseries, confirming their high effectiveness.

A high-performance liquid chromatography method was developed for determination of flunixin in bovine plasma. The extraction procedure was easily performed and made it possible to detect low concentrations of flunixin with high accuracy. The limit of quantitation was 7 ng/ml (relative standard deviation = 18%, n = 10). The analytic method permits processing of 60 samples/d. Flunixin, as well as the internal standard (diclofenac sodium), belong to the group of nonsteroidal anti-inflammatory drugs, which are known to have a high degree of binding to plasma proteins. Therefore, an evaluation of several buffer systems was undertaken to optimize analytic conditions. Cattle were given 2.2 mg of flunixin meglumine/kg of body weight. In experiment 1, single injections were administered IV to q cow and IM to 1 heifer (7 days apart), and pharmacokinetic variables were calculated. The IV data were best described by a two-compartment model. The half-life after single IV or IM administration was around 4.0 hours. In experiment 2, the decreasing flunixin concentration was determined after the last of either 4 IM injections daily (n = 3 cows) or 2 IM injections daily (n = 3 cows) administered during a 14-day postpartum period. The half-life, determined between 48 and 96 hours after the last dose, was approximately 26 hours in both groups, and flunixin could be detected in plasma up to 8 days, on average. The protein binding of flunixin was studied, using the method of equilibrium dialysis. Flunixin was found to have a high degree of protein binding (ie, 99.4 +/- 0.2%) at a flunixin concentration in plasma of 3 to micrograms/ml. Differences in protein binding between cattle were not found.

Microcytosis is a common laboratory finding in dogs with congenital portosystemic shunt (PSS), although its pathogenesis is not yet understood. Because the most common cause of microcytosis in dogs is absolute or relative iron deficiency, iron status was evaluated in 12 young dogs with PSS. Complete blood counting was done before surgical correction in all dogs, and in 5 dogs after surgery, by use of an automated hematology analyzer. Serum iron concentration and total iron-binding capacity (TIBC) were determined colorimetrically, and percentage of transferrin saturation was calculated. Erythrocyte protoporphyrin content was quantified by use of front-face fluorometry. Serum ferritin concentration was measured by use of ELISA. Serum ceruloplasmin content was determined colorimetrically (with p-phenylenediamine dihydrochloride as substrate) as an indirect indicator of subclinical inflammation, which may result in impaired iron utilization. Special stains were applied to liver (10 dogs; Gomori's) and bone marrow aspiration biopsy (7 dogs; Prussian blue) specimens for qualitative assessment of tissue iron content. Nonpaired Student's t-tests were used to compare serum iron concentration, TIBC, percentage of transferrin saturation, and erythrocyte protoporphyrin, ferritin, and ceruloplasmin concentrations in dogs with PSS with those in clinically normal dogs. All dogs had microcytosis before surgery; microcytosis resolved in 3 dogs after surgical correction. Serum iron concentration and TIBC were significantly lower, in PSS-affected dogs than in clinically normal dogs. Erythrocyte protoporphyrin, ferritin, and ceruloplasmin concentrations in PSS-affected dogs were not significantly different from those in healthy dogs. Excess iron was not detected consistently in liver or bone marrow samples. These results suggest that relative iron deficiency, perhaps associated with altered iron transport and not absolute iron deficiency, is related to microcytosis in dogs with PSS.