Variation in the pathogenic potential and molecular characteristics of bovid herpesvirus-4 isolates.

Seven bovid herpesvirus-4 (BHV-4) isolates recovered from various clinical conditions of cattle were studied for their pathogenic potential in pregnant rabbits. These viruses were originally recovered from respiratory and reproductive tract infections of cattle. A virus dose of 4 x 10(6.8)TCID50 per fetus was inoculated via the intrauterine route in 10- and 17-day pregnant rabbits. Clinical, virologic, and pathologic data were collected to compare the effect of each isolate on does and fetuses/kits. Three isolates (LVR-140, QVR-3140 and 86-068) caused abortion, fetal reabsorption and/or mummification in inoculated rabbits. Virus was recovered from tissues of inoculated rabbits (especially the spleen, ovaries and uterus) by organ explanation and/or co-cultivation. Intravenous inoculation of isolate 86-068 did not produce any clinical signs in either 10- or 17-day pregnant rabbits. All seven isolates of BHV-4 showed a predilection for the reproductive tract of pregnant rabbits but varied in the severity of disease signs produced. Variation was also observed in the genome of various isolates on the basis of restriction endonuclease (RE) analysis. Relationship of RE patterns to the variation in the pathogenic potential of seven BHV-4 isolates is discussed.

A study to compare the healing of a Plasma-TFE synthetic artery in the dog.

The physiochemical and healing characteristics of the Plasma-TFE synthetic artery (Atrium Medical Corp., Amherst, NH) were studied and compared to a similarly constructed polyethylene terephthalate graft without Plasma-TFE treatment. Plasma-TFE treatment is a method of coating a graft's surface with tetrafluoroethylene and was found to alter significantly the surface chemistry and energy of the graft. However, results of this study suggested that Plasma-TFE treatment had no effect on tissue penetration and neointima formation after implantation into the abdominal aorta of the dog for 8 weeks.

Replacement of the cervical and thoracic esophagus in dog using free jejunal autografts.

Free revascularized jejunal grafts based on a single branch of the mesenteric artery and vein were selected and used for replacement of the cervical esophagus in 20 dogs. The graft pedicle was transplanted to the left external jugular vein and the internal carotid artery using end-to-side microvascular anastomoses. The procedure was successful in all the dogs; however, five dogs had fistula formation that healed spontaneously. A similar jejunal autograft was used to replace the thoracic esophagus in 20 dogs. The recipient vessels were the internal thoracic artery and vein. Only four dogs survived. Thirteen dogs could not survive because of infection resulting from leakage of esophageal content from the esophagojejunal anastomoses into the thoracic cavity. Only two dogs had infarcted jejunal grafts. The four surviving dogs could swallow liquid and semisolid food but they never returned to solid food because of difficulties with swallowing. Graft survival was confirmed with endoscopy and arterial angiography. Narrowed jejunal graft lumen was apparent with contrast radiography and endoscopy. The jejunal grafts kept peristalsis and contracted in coordinated fashion with the proximal esophagus. At necropsy, wound healing was evaluated using bursting strength and bursting circular wall tension. Although slight adhesion and fibrosis around the grafts as well as slight inflammatory reaction around the suture material were observed, the jejunal grafts were grossly and microscopically normal. All esophagojejunal anastomoses healed and the jejunal mucosa looked normal.

Surgical reconstruction of partial circumferential esophageal defect in the dog.

Partial circumferential reconstruction of the cervical esophagus was evaluated in the dog. An esophageal defect 5.85 +/- 1.15 cm in length involving one-half of the circumference was repaired by direct closure (group I), using longus colli muscle patch grafts (group II), and using grafts of longus colli muscle lined with buccal mucosa (group III). The incidence of leakage, fistula formation, luminal stricture, peristalsis disturbance, lining loss, the quality of surface restoration, bursting strength, and wound healing were evaluated. No fistula formation or leakage was observed in any animal. Direct closure of the defect was easier to perform, led to less inflammatory reaction, and resulted in the highest bursting strength. However, this method was associated with luminal stricture and swallowing difficulties. The longus colli muscle patch grafts (group II) were associated with a slight to moderate luminal stricture, but had more inflammatory reaction and graft surface area contraction (62%) compared to group III. The longus colli muscle lined with buccal mucosa caused no stricture and slight surface area contraction (8%). Mucosal grafts remained viable and no lining loss was observed. Despite the loss of peristalsis at the level of the graft in 25% of the group III dogs, no clinical signs or swallowing difficulties were observed.

Persistence of bovid herpesvirus-4 in experimentally inoculated pregnant rabbits.

To study the persistence and reactivation of bovid herpesvirus-4 (BHV-4), pregnant rabbits were inoculated with BHV-4 via the intrauterine route. Disease production and virus shedding were monitored for up to 67 days post infection (DPI). Virus isolation was attempted from nasal, vaginal and buffy coat samples of all rabbits. Virus shedding was observed between 5 and 12 DPI but not thereafter. Some of the animals were given intramuscular injections of dexamethasone (DEX) for 4 consecutive days starting at 7 weeks post infection. One group of rabbits was euthanized at 5 days post-DEX treatment (58 DPI) and the other was euthanized 2 weeks post-DEX treatment (67 DPI). Virus shedding was not detected in either group but BHV-4 was recovered on multiple occasions from spleen, kidney, uterus, and ovary explants of both DEX-treated and non-treated rabbits indicating that BHV-4 can persist in these organs but cannot be reactivated by DEX. To further study the in vitro reactivation of persistent BHV-4, a methylating agent, hexamethylenebisacetamide (HMBA), was used in organ cultures of neural and extraneural tissues. Limited data on enhanced recovery of BHV-4 from spleen indicated that it may be the site of latency in BHV-4 infection.

Evaluation of pregnant rabbits as a laboratory model for bovid herpesvirus-4 infection.

A field strain (87-8363) of bovid herpesvirus-4 (BHV-4) isolated from an aborted bovine fetus was used to inoculate pregnant rabbits. Eleven rabbits in midgestation were alloted to 4 groups consisting of 3 infected groups and 1 control group. Rabbits were inoculated with BHV-4 or mock-infected cell culture preparations via IV, intravaginal, and intrauterine routes. Mild vulvovaginitis and endometritis were observed after intravaginal and IV inoculation of BHV-4, whereas intrauterine inoculation of BHV-4 resulted in abortion of hemorrhagic fetuses and nonsuppurative endometritis. Virus was successfully isolated from organ explants of fetal tissues. Rabbits seroconverted 1 week after infection as detected by results of an indirect immunofluorescence assay.

Effects of 1 alpha,25-dihydroxycholecalciferol on disuse osteoporosis in the dog: a histomorphometric study.

Disuse osteoporosis was produced in dogs by immobilization of the left rear limb in a plaster cast. The trabecular bone volume of the calcaneus was then determined following treatment with 1 alpha,25-dihydroxycholecalciferol for 4 weeks with oral dosages of 60 to 240 ng/kg of body weight. The trabecular bone volume percentage of the immobilized calcaneus was in direct relation to the dosage of 1 alpha,25-dihydroxycholecalciferol.

Comparison of crystalloid and sanguineous cardioplegic solutions in the dog.

Myocardial protection provided by 2 types of cold cardioplegic solution and by cold saline solution was compared experimentally in dogs on cardiopulmonary bypass. Techniques and solutions used simulated clinical conditions. Serial biopsies of myocardium were assayed for adenosine triphosphate, adenosine diphosphate, and adenosine monophosphate. Maintenance and recovery of each phosphate was calculated as a percentage of the prebypass value for each type of solution; these values were used to compare the myocardial protection afforded by the 3 solutions. A difference in these values was not observed between the 2 types of cardioplegic solution; both values were greater than for the control solution, which may indicate improved myocardial protection with cardioplegic arrest.

Posologic evaluation of clindamycin, using a canine model of posttraumatic osteomyelitis.

Posttraumatic osteomyelitis attributable to Staphylococcus aureus infection was experimentally induced in 30 dogs, after which the dogs were treated with clindamycin at various dosage regimens. Of the regimens evaluated, oral administration of 11 mg of clindamycin/kg of body weight twice daily for 28 days was the most effective treatment for the osteomyelitis.

Effects of intramuscular or interpleural administration of morphine and interpleural administration of bupivacaine on pulmonary function in dogs that have undergone median sternotomy.

OBJECTIVE: To evaluate effects of interpleural or IM administration of morphine and interpleural administration of bupivacaine on pulmonary function in dogs that have undergone median sternotomy. DESIGN: Experimental trial. ANIMALS: 18 healthy dogs. PROCEDURE: Dogs underwent median sternotomy and were randomly assigned to groups of 6 dogs each. Group-A dogs were given morphine (1.0 mg/kg of body weight) i.m.; group-B dogs were given 0.5% bupivacaine (1.5 mg/kg) interpleurally; and group-C dogs were given morphine (1.0 mg/kg) interpleurally. Heart rate; systolic, diastolic, and mean arterial pressures; rectal temperature; pain score; and arterial blood gas partial pressures were measured and pulmonary function testing was performed immediately after extubation (time 0) and up to 48 hours later. Serum cortisol and morphine concentrations were measured at time 0 and up to 12 hours after surgery. RESULTS: There was a significant decrease in pH, PaO2, mean oxygen saturation of hemoglobin, and dynamic compliance; and a significant increase in PaCO2, alveolar-arterial difference in partial pressure of oxygen, pulmonary resistance, and work of breathing for dogs in all groups after surgery. Serum cortisol concentrations were significantly increased, compared with preoperative values, in all dogs. Serum cortisol concentrations were significantly higher in group-B dogs between 3 and 5 hours after surgery, compared with group-A dogs. CONCLUSIONS: Median sternotomy was associated with significant alterations in pulmonary function. Effects of interpleural administration of bupivacaine and morphine were similar to effects of i.m. administration of morphine.

Evaluation of pulmonary function and analgesia in dogs after intercostal thoracotomy and use of morphine administered intramuscularly or intrapleurally and bupivacaine administered intrapleurally.

Eighteen dogs undergoing lateral thoracotomy at the left fifth intercostal space were randomly assigned to 1 of 3 postoperative analgesic treatment groups of 6 dogs each as follows: group A, morphine, 1.0 mg/kg of body weight, IM; group B, 0.5% bupivacaine, 1.5 mg/kg given interpleurally; and group C, morphine, 1.0 mg/kg given interpleurally. Heart rate, respiratory rate, arterial blood pressure, arterial blood gas tensions, alveolar-arterial oxygen differences, rectal temperature, pain score, and pulmonary mechanics were recorded hourly for the first 8 hours after surgery, and at postoperative hours 12, 24, and 48. These values were compared with preoperative (control) values for each dog. Serum morphine and cortisol concentrations were measured at 10, 20, and 30 minutes, hours 1 to 8, and 12 hours after treatment administration. All dogs had significant decreases in pHa, PaO2, and oxygen saturation of hemoglobin, and significant increases in PaCO2 and alveolar-arterial oxygen differences in the postoperative period, but these changes were less severe in group-B dogs. Decreases of 50% in lung compliance, and increases of 100 to 200% in work of breathing and of 185 to 383% in pulmonary resistance were observed in all dogs after surgery. Increases in work of breathing were lower, and returned to preoperative values earlier in group-B dogs. The inspiratory time-to-total respiratory time ratio was significantly higher in group-B dogs during postoperative hours 5 to 8, suggesting improved analgesia. Blood pressure was significantly lower in group-A dogs for the postoperative hour. Significant decreases in rectal temperature were observed in all dogs after surgery, and hypothermia was prolonged in dogs of groups A and C. Significant differences in pain score were not observed between treatment groups. Cortisol concentration was high in all dogs after anesthesia and surgery, and was significantly increased in group-B dogs at hours 4 and 8. Significant differences in serum morphine concentration between groups A and C were only observed 10 minutes after treatment administration. In general, significant differences in physiologic variables between groups A and C were not observed. Results of the study indicate that the anesthesia and thoracotomy are associated with significant alterations in pulmonary function and lung mechanics. Interpleurally administered bupivacaine appears to be associated with fewer blood gas alterations and earlier return to normal of certain pulmonary function values. Interpleural administration of morphine does not appear to provide any advantages, in terms of analgesia or pulmonary function, compared with its IM administration.

Osteoarthrosis in a wolf (Canis lupus) radio-tracked in Minnesota.

Osteoarthrotic changes are described in the skeleton of an old wolf (Canis lupus) from Minnesota. Osteophyte formation appeared sufficient to restrict severely the range of motion of the joints. Despite this impairment the wolf ranged over 100 km2 and killed a minimum of one or two adult white-tailed deer (Odocoileus virginianus) during a 6-week period between capture and death.

Osteomyelitis in the dog: a review of 67 cases.

The clinicopathologic aspects of bacterial osteomyelitis in 67 dogs were compared. The femur, humerus, metacarpals, metatarsals, and phalanges were the bones most commonly affected. In most dogs, the infection was attributed to repair of fracture by open reduction. Staphylocuccus spp and Streptococcus spp were the organisms most frequently isolated. Most dogs had chronic osteomyelitis at the time of initial examination.

Idiopathic, duodenogastric intussusception in an adult dog.

An adult Basset Hound was examined because of acute vomiting, signs of depression, dehydration, and signs of abdominal pain. Radiography revealed a soft tissue dense mass in the stomach. At exploratory laparotomy, 75% of the stomach was black, and the pylorus, proximal portion of the duodenum, and pancreas were found inverted into the stomach. The dog was euthanatized.

Bullous emphysema and recurrent pneumothorax in the dog.

Six cases of recurrent pneumothorax requiring surgical intervention in the dog were reviewed. Radiography was not useful in identifying the source of air leakage. A median sternotomy approach was useful for identifying and removing involved lung tissue. All 6 dogs had microscopic evidence of bullous emphysema. Bronchiolitis, thickened pleura, and bronchiolar smooth muscle hypertrophy also were noticed. Underlying mild obstructive lung disease alone or in combination with a defect in pulmonary collagen probably predisposed these dogs to bullous emphysema and recurrent pneumothorax. Of the 6 dogs, 3 survived for at least 2 years after surgery.

Septic polyarthritis associated with bacterial endocarditis in two dogs.

Two dogs were examined because of chronic shifting lameness. In each case, lameness was attributed to septic polyarthritis, as documented by synovial fluid analysis and culture. In 1 dog, antemortem diagnosis of bacterial endocarditis was verified by clinical and culture data. Treatment of both dogs was unsuccessful, and necropsy of each dog revealed bacterial endocarditis with coexistent septic polyarthritis. Bacteriologic blood cultures yielded an anaerobic Streptococcus sp (dog 1) and Pasteurella multocida (dog 2).

Pheochromocytoma in dogs: 13 cases (1980-1985).

Thirteen cases of canine pheochromocytoma seen at the University of Minnesota Veterinary Teaching Hospital between 1981 and 1985 were reviewed. In 8 cases, the neoplasms were locally invasive; in the remaining cases, they were confined to the adrenal gland. Clinical signs compatible with fatal cardiovascular collapse secondary to a hypertensive or arrythmic episode were observed in 6 of 8 dogs with invasive neoplasms that died during examination or shortly thereafter. The remaining 2 dogs with invasive neoplasms had antemortem diagnoses of adrenal gland neoplasm with metastases and were euthanatized. Invasion or encroachment of the caudal vena cava in 6 dogs and encroachment of the aorta and other regional vasculature in 2 dogs were discovered at necropsy. In 5 dogs, the noninvasive pheochromocytoma was found incidentally during necropsy.

Postoperative complication of cervical fracture repair in a dog.

Fracture and luxation of the second cervical vertebra of a dog were repaired with braided polyester sutures. After 28 months, the dog became ataxic. Compression of the spinal cord at C1-2 was seen on a myelogram. Surgical exploration of the area revealed a granuloma associated with the sutures and compressing the spinal cord. After the granuloma was removed, the dog recovered and has remained neurologically normal for 21 months. The abnormal tissue was determined histologically to be a pyogranuloma.

Colonic perforation following neurosurgical procedures and corticosteroid therapy in four dogs.

Perforation of the proximal descending colon occurred in four Dachshund dogs, each of which died 5 to 10 days following neurosurgical procedures. The complication was believed to be associated with parenteral use of dexamethasone. Correct antemortem diagnosis was made in only one of the four cases, probably because signs of a perforated viscus were so modified by the antiphlogistic effects of corticosteroids as to prevent early detection of the complication.

Colonic perforation in corticosteroid-treated dogs.

Clinical findings for 5 new cases of colonic perforation in corticosteroid-treated dogs were presented and 8 other cases from the literature were reviewed. Colonic perforation was a fatal complication in all 13 dogs, 12 of which had had recent major surgery. Ten dogs were neurosurgical patients, 1 dog received medical therapy for head trauma and nonambulatory paresis, and 2 dogs were operated on for non-neurologic conditions. Dexamethasone was the most frequently used corticosteroid, and 12 dogs received a mean cumulative dose of 6.4 mg/kg over an average period of 5.1 days. Depression, anorexia, and emesis, the most frequent signs attending colonic perforation, became evident 3 to 8 days after surgery. Signs preceded death by an average of 22.3 hours. Correct antemortem diagnosis (5 dogs) and surgical intervention (3 dogs) had no effect on eventual outcome (mortality = 100%). Colonic perforation most frequently developed in the proximal descending portion and always involved the antimesenteric border. Gross fecal contamination of the peritoneal cavity and acute generalized peritonitis were evident in all but one dog. Adhesions were observed at the lesion site in 6 dogs, but prevented gross soilage in only one dog.