Biomedical subjects
Publications and source records attributed to D D Caywood.
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.
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.
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The effect of acetylsalicylic acid (aspirin) on bone mass and bone prostaglandin E (PGE) in immobilization osteoporosis was studied in 12 growing dogs using a unilateral hind limb cast-fixation model. Osteoporosis was induced by fiberglass-cast immobilization of the right hind limb for 4 weeks, with the left hind limb as a control. Six dogs received buffered aspirin at 25 mg/kg body weight per os every 8 hours; 6 dogs received no treatment. All the dogs were killed after 4 weeks, and bone samples were collected. Bone mineral content of the distal tibial metaphysis was measured by single-photon absorptiometry. In vitro release of PGE from the calcaneus, tibial cortical bone, tibial cancellous bone, and ilium were measured using a specific radioimmunoassay for PGE. Compared with the controls, the casted limb of untreated dogs had half the bone mass and a twofold increase in bone PGE. Aspirin treatment was associated with a 65 percent reduction in bone PGE and a 13 percent bone mass sparing effect. These results provide indirect evidence that PGE plays a role in immobilization osteoporosis.
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.
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.
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.
This article reviews the classification, etiopathogenesis, and treatment for the various forms of pneumothorax. Traumatic and nontraumatic pneumothoraces are discussed. New theories on the etiology and treatment of primary spontaneous and secondary pneumothorax are mentioned.
The diagnosis and management of surgical diseases of the esophagus are discussed. Esophageal foreign bodies, strictures, esophagobronchial fistulas, diverticula, gastroesophageal intussusception, hiatal hernias, and megaesophagus are included in the discussion.
This article reviews common causes and types of thoracic trauma in the dog. A triage approach for the diagnosis and immediate treatment of thoracic trauma is presented. Reconstructive procedures of the thoracic wall, which may be necessary following trauma or surgical resection of diseased tissue, are described.
Common pulmonary lesions that require partial or complete lobectomy include abscesses, cysts, bullae, neoplasms, lacerations, foreign bodies, and lung lobe torsions. This article discusses the instrumentation, surgical approaches and techniques, and postoperative management of partial and complete lung lobectomy.
Thirty-one primary canine pancreatic endocrine tumors and their metastases were studied histologically and immunohistochemically for the presence of insulin, glucagon, somatostatin, pancreatic polypeptide (PP), gastrin, and adrenocorticotrophic hormone (ACTH). Tumors were also evaluated for the presence of amyloid. The cytoarchitectural pattern of 25 of 31 primary tumors was predominantly solid, whereas three tumors were mostly glandular, two were unclassified, and one had a gyriform pattern. Cells with insulin immunoreactivity were found in 30 of 31 tumors and were found in all cases in which there was clinical evidence of inappropriate insulin secretion. Insulin was the only hormone demonstrable in three of the 30 tumors, but cells immunoreactive for other hormones were also present in various combinations in most tumors [i.e., glucagon (13 of 30), somatostatin (17 of 30), PP (25 of 30), and gastrin (2 of 30)]. One tumor contained only cells with glucagon and PP immunoreactivity. Amyloid was found in ten of 31 primary tumors but was not detected in metastases. Cells with insulin immunoreactivity were the only cell type consistently present in tumors containing amyloid. Amyloid deposits did not immunoreact with any of the antisera. Seventeen of 31 dogs had metastasis of the pancreatic endocrine tumor to regional lymph nodes, liver, or both. All metastases available for study (15 of 17) contained cells with insulin immunoreactivity and some contained cells with PP or somatostatin immunoreactivity. No statistically significant (P greater than 0.05) differences in tendency to metastasize were found when pancreatic endocrine tumors were compared by region of origin, cytoarchitectural pattern, presence of amyloid, or by number of hormones contained within the tumor.
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.
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.
Surgery is indicated for patients with obstructive uropathy; calcium oxalate, calcium phosphate, silica, and perhaps cystine uroliths; uroliths refractory to medical dissolution; nephrolithiasis and progressive renal dysfunction; anatomic defects predisposing to urinary tract infection; and problems precluding medical management. The goals of surgical management include removal of all uroliths while preserving organ function, eliminating partial or complete obstruction to urine outflow, and correction of anatomic abnormalities that predispose the patient to infection and or urolithiasis.
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.
Hypertrophic osteopathy was diagnosed in a dog with a bronchial foreign body and lobar pneumonia. Hypertrophic osteopathy is generally associated with primary or secondary neoplasms of the lungs and rarely associated with nonneoplastic thoracic lesions. The foreign body and affected lung lobe were removed by pneumonectomy, resulting in recovery of the dog and resolution of the hypertrophic osteopathy lesions.
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.