Repeatability of measurements of peak and mean tracheal and pharyngeal pressures in exercising horses was determined. Five athletically fit horses were subjected to repeated (n = 5) standardized exercise trials. Static pressures in the trachea, nasopharynx, and mask were determined. At least 96% of all mean pressure measurements were within 5 cm of H2O of the mean value for any horse. Peak pressure measurements were less repeatable, but at least 96% of all measurements were within 10 cm of the mean peak measurements for any horse. In 10 horses galloping at 14 m/s, the 95% confidence interval for peak tracheal and pharyngeal inspiratory pressures ranged from -40 to -50 cm of H2O and -20 to -26 cm of H2O, respectively. During expiration, the 95% confidence interval for peak tracheal and pharyngeal pressure at the same speed ranged from 15 to 28 cm of H2O and 10 to 24 cm of H2O respectively. During inspiration, horses with induced laryngeal hemiplegia had static pressure measurements generally outside that range. We conclude that determination of tracheal and pharyngeal pressures is a potentially useful adjunct for assessment of the proximal portion of the respiratory tract.

The formylated peptide, N-formyl-methionyl-leucyl-phenylalanine, at concentration of 0.22 micromolar, failed to stimulate canine neutrophils to produce adequate amounts of superoxide. Furthermore, addition of cytochalasin B did not augment superoxide generation appreciably.

We characterized the clinicopathologic manifestations of experimentally induced endotoxin-induced mastitis. Responses to hypertonic fluid therapy also were assessed. Eight cows received 1 mg of endotoxin by in infusion in the left forequarter. Four hours after endotoxin administration, cows received 0.9% NaCl, 5 ml/kg of body weight (n = 4) or 7.5% NaCl, 5 ml/kg (n = 4) IV. Endotoxin-infused cows had expanded plasma volume, hyponatremia, transient hyperchloremia and hypophosphatemia, increased serum glucose concentration, and decreased serum activities of liver- and muscle-specific enzymes. Calculated plasma volume increased at 6 hours in cows receiving hypertonic NaCl, and at 12, 24, and 48 hours after endotoxin infusion in both groups. Concurrent observations of decreased serum protein concentration, erythrocyte count, and hematocrit supported observations of increased plasma volume. Relative plasma volume was greater in cows receiving hypertonic NaCl (124.3%) than in cows receiving isotonic NaCl (106.6%) at 6 hours after endotoxin infusion. Cattle receiving hypertonic NaCl had increased voluntary water intake after IV fluid administration. Increased water consumption was not accompanied by increased body weight, indicating probable occurrence of offsetting body water loss. Serum sodium concentration in cows receiving hypertonic NaCl was increased 2 hours after fluid administration, but the magnitude of the change was minimal (< 4 mmol/L) and transient, indicating rapid equilibration with either interstitial or intracellular spaces. Serum sodium concentration was decreased in cows receiving isotonic NaCl at 12, 24, and 48 hours after endotoxin administration, compared with concentration prior to endotoxin administration, indicating selective loss of sodium.

A technique for measuring upper airway resistance was developed in awake untrained dolichocephalic and mesaticephalic dogs. Twenty healthy dogs, 10 Collies (group dolichocehalic) and 10 mixed-breed dogs (group B-mesaticephalic), were studied. All dogs tolerated the procedure well and adverse effects were not observed. Mean (+/- SEM) value for upper airway resistance was 7.1 +/- 0.50 cm of H2O/L/s. There was a trend toward lower upper airway resistance (Ruaw) values in group-A dogs, compared with those in group-B dogs. Values of Ruaw were reproducible for an individual dog. The mean individual dog coefficient of variation for Ruaw was 7.5%. The overall Ruaw coefficient of variation for all 20 dogs was 31.4%. This technique for measuring upper airway resistance in dogs is clinically applicable for objectively assessing response to treatment of obstructive upper airway disorders.

Distribution of pulmonary nerves immunoreactive for either substance P or calcitonin gene-related peptide was determined, using immunohistochemical methods on healthy lungs from adult equids. The overall patterns of distribution of substance P and calcitonin gene-related peptide-like immunoreactivity were similar. Distribution of immunoreactive nerves was not uniform throughout the lungs; nerve fibers immunoreactive for these peptides were more frequently observed near the hilus of the lung than in the caudal lobes or in the periphery of the lung. Nerve fibers mununoreactive for substance P or calcitonin gene-related peptide were most abundant in the propria of the trachea and large airways, particularly within and directly below the airway epithelium, they were also frequently associated with bronchial and pulmonary vessels. Presence of nerve fibers immunoreactive for substance P and calcitonin gene-related peptide in peribronchial neural ganglia indicated that these sensory nerves may modulate parasympathetic regulation of pulmonary function. Nerve fibers immunoreactive for substance P and calcitonin gene-related peptide were, therefore, well placed to detect inhaled agents and to contribute to the pulmonary response to irritants and pathogens.

Inoculation of 53 ewes after 35, 45, 60, or 80 days of gestation with bluetongue virus serotypes 10, 11, 13, or 17, or with epizootic hemorrhagic disease virus serotypes 1 or 2, resulted in overt clinical disease in the 47 ewes inoculated with bluetongue virus but not in the 6 ewes inoculated with epizootic hemorrhagic disease virus. None of the lambs produced by these ewes had developmental defects or any evidence of persistence of viremia.

Monoclonal antibody (MAB) B72.3, which recognizes human tumor-associated glycoprotein-72, has immunoreactivity for malignant epithelial neoplasms in human beings and dogs. To further characterize the range of immunoreactivity of MAB B72.3 in canine tissues, MAB B72.3 and 2 other tumor-associated glycoprotein-72 antibodies (MAB CC49 and CC83) were tested against a wide spectrum of normal tissues from dogs. Immunoreactivity was detected, using an avidin-biotin-complex immunoperoxidase method. Monoclonal antibody B72.3 did not stain most types of normal canine tissues, but various types of epithelial cells within the gastrointestinal and respiratory tract mucosae, salivary gland, esophagus, epididymis, uterus, thymus, hair follicle, and apocrine glands of the anal sac had variable staining with MAB B72.3. A similar range of immunoreactivity in comparable types of normal tissues was seen for MAB CC49 and CC83; however, MAB CC49, but not MAB B72.3 and CC83, stained the endothelium of capillaries and small vessels in most normal tissues. Staining of frozen and paraffin-embedded tissues was similar. In conclusion, we found that MAB B72.3, CC49, and CC83 had selected immunoreactivity for specific types of normal canine epithelial cells, especially those involved with mucin production.

Thirty-one clinically normal Cocker Spaniels, Miniature Schnauzers, and Doberman Pinschers (28 female, 3 male) 7 to 8 years old were uninephrectomized (month -2) to increase the risk of renal damage associated with reduction of renal mass. Two diets, differing principally in protein concentration, were used to test the hypothesis that high dietary protein intake causes renal damage in aging dogs. For 2 months after uninephrectomy, all dogs were fed diet A (18% protein). After glomerular filtration rate (GFR) was measured (month 0), 16 dogs were assigned to group A and were fed diet A for an additional 48 months. The other 15 dogs were assigned to group B, and were fed diet B (34% protein) for the subsequent 48 months. At 6-month intervals, GFR and urine protein-to-creatinine ratio (UP/C) were determined. At 48 months, terminal studies were done, survivors were euthanatized, and tissues were examined. Of 16 dogs in group A, 10 survived, compared with 13 of 15 in group B. Among survivors, a significant difference in GFR was not found between groups A and B, and decrease in GFR was not evident with time in either group. At 48 months, oral administration of casein caused minor acute effects on GFR and renal plasma flow in dogs of groups A and B. The UP/C values increased significantly (P = 0.001) from baseline values, but the increase was not progressive. The UP/C values were not affected by diet. Some dogs in both groups developed UP/C > 1.0. Morphologic studies performed on kidneys removed at -2 months (nephrectomy) and at 48 months (necropsy) revealed increased kidney weight in both groups at month 48, compared with month -2 (P = 0.003); at month 48, kidney weight change was significantly (P = 0.004) greater in group-B than in group-A dogs. Increased glomerular area at month 48, compared with month -2, was significantly (P= 0.000) related to time, but not to diet. Significant (P = 0.000) increase in glomerular mesangial matrix, interstitial fibrosis (P = 0.001), cell infiltration (P = 0.000), and lesions of the renal pelvis (P = 0.04) was observed between month -2 and month 48. Time, representing combined effects of uninephrectomy and aging, was the major factor responsible for the morphologic changes. Diet effects were significance (P = 0.008) for cell infiltration, but did not reach significance for mesangial matrix accumulation, fibrosis, or pelvic lesions. Kidney mineral analysis revealed no renal mineralization in either group between -2 and 48 months. Results indicated that GFR did not decrease with time during the geriatric period studied, but severity of renal lesions was increased. Effects of time and uninephrectomy, although not separable, were more important than those of dietary protein intake on progression of renal lesions.

Hemodynamic and analgesic effects of medetomidine (15 microgram/kg of body weight, IM) and etomidate (0.5 mg/kg, IV, loading dose; 50 micrograms/kg/min, constant infusion) were evaluated in 6 healthy adult Beagles. Instrumentation was performed during isoflurane/ oxygen-maintained anesthesia. Before initiation of the study, isoflurane was allowed to reach end-tidal concentration less than or equal to 0.5%, when baseline measurements were recorded. Medetomidine and atropine (0.044 mg/kg) were given IM after recording of baseline values. Ten minutes later, the loading dose of etomidate was given IM, and constant infusion was begun and continued for 60 minutes. Oxygen was administered via endotracheal tube throughout the study. Analgesia was evaluated by use of the standard tail clamp technique and a direct-current nerve stimulator. Sinoatrial and atrial-ventricular blocks occurred in 4 of 6 dogs within 2 minutes after administration of a medetomidine-atropine combination, but disappeared within 8 minutes. Apnea did not occur after administration of the etomidate loading dose. Analgesia was complete and consistent throughout 60 minutes of etomidate infusion. Medetomidine significantly (P < 0.05) increased systemic vascular resistance and decreased cardiac output. Etomidate infusion caused a decrease in respiratory function, but minimal changes in hemodynamic values. Time from termination of etomidate infusion to extubation, sternal recumbency, standing normally, and walking normally were 17.3 +/- 9.4, 43.8 +/- 14.2, 53.7 +/- 11.9, and 61.0 +/- 10.9 minutes, respectively. All recoveries were smooth and unremarkable. We concluded that this anesthetic drug combination, at the dosages used, is a safe technique in healthy Beagles.

Observations were made on development of diarrhea in special-fed calves (n = 460) on 8 commercial facilities during 2 successive 16-week production cycles at weeks 0, 2, 4, 8, 12, and 16. A total of 23% were affected, with peak number of calves with diarrhea observed at week 0. Suspected enteropathogens were identified in 86% of these calves, most commonly cryptosporidia, coronavirus, and rotavirus. Identified potential zoonotic pathogens included Giardia and Salmonella spp and verotoxigenic Escherichia coli. Noncytopathic bovine viral diarrhea virus was isolated from 6 calves that had repeated bouts of illness. Only 22% of calves entering the veal facilities had adequate transfer of passive immunity. At week 0, serum IgG concentration in calves that subsequently died or had diarrhea was lower (P < 0.001) than that in healthy calves. All calves that died (n = 6) during the first 4 weeks of production had complete failure of transfer of passive immunity.