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Biomedical subjects

T W Fossum

Publications and source records attributed to T W Fossum.

At least 55 records · Page 3Linked to original sources
PubMed1986

Chylothorax in 34 dogs.

Thirty-four dogs with chylothorax were studied retrospectively. In 24 dogs, chylothorax appeared to be idiopathic, with only 10 dogs having evidence of neoplasia or trauma. Rupture of the thoracic duct secondary to trauma appeared to be a much less common cause for the development of a chylous pleural effusion than that reported previously. The Afghan Hound was the breed most commonly affected, comprising 37.5% of the dogs in the idiopathic category and 26.5% of all dogs with chylothorax. A clear correlation between the cause of chylothorax and age was not apparent, and gender and neutering appeared to have no relationship to the development of chylothorax in the dog.

Animals↗
PubMed1986

Evaluation of cholesterol and triglyceride concentrations in differentiating chylous and nonchylous pleural effusions in dogs and cats.

Serum and pleural fluid cholesterol and triglyceride concentrations and cholesterol/triglyceride ratios were determined in 9 dogs and 9 cats with pleural effusion (8 nonchylous, 10 chylous). The pleural fluid triglyceride concentrations were significantly higher (P less than 0.05) and the pleural cholesterol/triglyceride ratios were significantly lower (P less than 0.05) in chylous effusions than in nonchylous effusions in all animals. There were no differences in serum cholesterol and triglyceride concentrations and serum cholesterol/triglyceride ratios for chylous and nonchylous effusions in either species. There also were no differences in pleural fluid cholesterol concentrations between the 2 groups in the dog or cat. It was concluded that determinations of cholesterol/triglyceride ratios may be an accurate method for helping distinguish chylous from nonchylous effusions in dogs and cats.

Animals↗
PubMed1986

Lymphangiographic evaluation of experimentally induced chylothorax after ligation of the cranial vena cava in dogs.

Ligation of the cranial vena cava (CrVC) distal to the entrance of the azygous vein resulted in chylothorax in 7 of 10 dogs. Of the remaining 3 dogs, 1 developed a serosanguineous effusion that did not become chylous, and 2 dogs did not develop pleural effusion. In 2 of the 7 dogs developing chylothorax, the pleural effusion became serosanguineous within 2.5 weeks after CrVC ligation. Mesenteric lymphangiography was performed 2 to 6 weeks after ligation of the CrVC. Lymphangiectasia was seen in 4 dogs with chylothorax, but was not seen in the 3 dogs with serosanguineous effusions or the 2 dogs that did not develop effusions. One dog with chylothorax died prior to repeat lymphangiography. Less dye entered the thoracic duct, and alternate lymphaticovenous communications to the caudal vena cava were evident in the dogs without chylothorax. Ligation of the thoracic duct at the lymphaticovenous junction was performed in 3 dogs. These dogs did not develop pleural effusion. Lymphangiography was performed immediately after ligation and indicated filling of abdominal lymphatics but not of the thoracic duct. Lymphangiographic findings 6 weeks after ligation also indicated filling of intestinal lymphatics. Results of the present study indicated that ligation of the CrVC causes chylothorax, and that thoracic lymphangiectasia is a consistent finding in animals with experimental chylothorax. Obstruction of the thoracic duct did not induce lymphangiectasia or chylothorax. Impedence of thoracic duct flow into the CrVC may be a cause of clinical chylothorax in the dog.

Animals↗
PubMed1985

Mesenteric lymphography and ligation of the thoracic duct in a cat with chylothorax.

Mesenteric lymphography was used to identify and ligate the thoracic duct in a 1-year-old Himalayan cat with chylothorax. Lymphography revealed the thoracic duct to be intact; however, multiple dilated lymphatics, indicative of lymphangiectasia were evident in the cranial portion of the thorax. Hemostatic clips were used to ligate the thoracic duct. The effusion stopped, and 9 months after surgery, effusion has not recurred.

Animals↗
PubMed1985

Surgical correction of primary pneumothorax in a dog.

Surgical repair of primary pneumothorax in a dog was performed by a median sternotomy and partial lung lobectomies using an automatic suturing device. A median sternotomy was performed since the location of the lesion was undetermined preoperatively. The automatic suturing device provided a quick, simple, and secure method of performing the partial lobectomies. Ruptured blebs and subpleural emphysema were present in the excised pulmonary tissue. Mechanical pleurodesis was also performed in an attempt to prevent recurrence. Large-gauge orthopedic wire was used to close the sternotomy in order to minimize postoperative complications. On follow-up evaluation 6 months later, the dog was normal.

Animals↗
PubMedDate not supplied

Collateral circulation in experimental coarctation of the aorta in minipigs: a possible association with hypertrophied vasa vasorum.

Experimental coarctation of the thoracic aorta was produced in 13 adult Yucatan minipigs by placing a gradually expanding "C-shaped" occluder around the aorta. The aortic constriction was standardized by measuring the blood pressure above the coarctation, with a mean arterial pressure of 165-170mmHg as the target. The pigs were humanely killed after 8 weeks of hypertension. No deaths were associated with constriction of the aorta, and neither rear limb weakness nor neurological dysfunction was noted. The lack of clinical signs in these animals suggested the development of an extensive collateral circulation. Collateral vessels, which were verified angiographically, included intercostal arteries, muscular intercostal arteries, and the internal thoracic artery. In two of the animals in which the thoracic aorta was completely occluded, revascularization also occurred via small arterial channels. Histologically, there was a marked increase in the number of vessels as well as significant hyperplasia and hypertrophy of smooth muscle of adventitial vasa vasorum. These findings support the hypothesis that collateralization of occluded thoracic aortas may be aided by hypertrophy of the vasa vasorum. To our knowledge, these vessels have not previously been shown convincingly by histopathological methods to revascularize occluded large arteries such as the aorta.

Angiography↗
PubMedDate not supplied

Complications common to ventricular assist device support are rare with 90 days of DeBakey VAD support in calves.

The DeBakey VAD is a miniaturized, electromagnetically driven axial flow pump intended for long-term ventricular assist. Safety and performance data from six calves implanted with the complete DeBakey VAD system are reported elsewhere; here we describe complications and necropsy findings for these same six animals, all of which survived 90 days. The study was conducted according to a uniform protocol, which included anticoagulation and antibiotic prophylaxis. Clinical complications tracked included bleeding, cardiovascular abnormalities (e.g., arrhythmias, tachycardia unrelated to pain, bradycardia), hemolysis, hepatic dysfunction, renal dysfunction, thromboembolism (neurologic or peripheral), or infection. Each adverse event was retrospectively categorized with regard to severity (mild, moderate, severe) and relationship to device. Clinical findings were confirmed by necropsy. There was no evidence of systemic infection, thromboembolism, hemolysis, or renal or hepatic dysfunction in these six animals during the study period. A single adverse event was noted in each of two of the calves. Both events were considered mild according to the predefined criteria. Bleeding related to the surgical implantation procedure and requiring reoperation occurred in one animal. The other animal had evidence of a superficial infection at the exit site of the cables on the left lateral thoracic wall; the infection did not extend into the thoracic cavity. Chronic, healed small renal infarct scars were present in several animals. Mild valvular endocardiosis was observed in two calves and mild fibroelastosis was present in the endocardium at the site of the inflow cannula in three calves; however, these lesions were not considered clinically significant. No other gross or histologic abnormalities were noted at necropsy. In conclusion, calves implanted with the complete DeBakey VAD for 90 days demonstrated few complications and had no significant necropsy findings. Complications common to ventricular assist device (VAD) support (i.e., hemolysis, infection, bleeding, thromboembolism) were rare during long-term support (90 days) with the DeBakey VAD.

Animals↗
PubMedDate not supplied

Management of intractable pleural effusion in a dog with pleuroperitoneal shunt.

Persistent nonchylous pleural effusion followed thoracic duct ligation for chylothorax in a dog. Attempts at tetracycline pleurodesis twice failed to reduce the quantity of pleural effusion. Repeated thoracentesis caused malnutrition and hypoproteinemia. A modified Denver peritoneal-venous shunt was implanted to internally drain the pleural fluid into the peritoneal cavity. Normal body weight and plasma protein concentration were regained in 40 days. Digital compression of the pump chamber alleviated the signs of respiratory compromise, without complication. At 50 weeks post-installation, a proteinaceous clot obstructed the original efferent pump valve, necessitating shunt replacement. Eight weeks after replacement, the dog was asymptomatic.

Animals↗
PubMedDate not supplied

Exploratory celiotomy in 200 nontraumatized dogs and cats.

Two hundred dogs and cats undergoing exploratory celiotomy for reasons other than trauma were grouped by disease classification and by body system affected. There were 61 animals in which infection or inflammation predominated, 63 animals with neoplasia, and 76 animals with noninflammatory and non-neoplastic conditions. Body systems affected were digestive, lymphatic, urinary, reproductive, other, and undetermined. Seventy-three percent of the animals survived the hospitalization period; survival rates for animals with infection or inflammation, neoplasia, and other disorders were 69%, 60%, and 86%, respectively. Within the same groups, the exploratory celiotomy provided strictly diagnostic information in 72%, 79%, and 24% of the animals, and surgical treatment was provided to 28%, 21%, and 58% of the animals, respectively. Intraoperative cytologic and histologic diagnoses were consistent in 78% of the animals; the consistency rates for animals with infection or inflammation, neoplasia, and other disorders were 81%, 88%, and 59%, respectively. Complications after surgery were observed in 30% of the animals, with 60% of the complications disease related. Complications were observed in six animals with reproductive disorders (67%), six animals with urinary disease (46%), 35 animals with digestive disease (29%), and three animals with lymphatic disease (13%).

Abdomen↗
PubMedDate not supplied

Evaluation of thoracic duct healing after experimental laceration and transection.

Healing of the thoracic duct (TD) was evaluated clinically and histologically in six healthy dogs. A 2.5 cm longitudinal laceration of the caudal TD was created in three dogs and the caudal TD was completely transected in three other dogs. The site of the defect was identified by placing one 4-0 stainless steel suture in the tissue adjacent to the TD defect. All dogs developed a chylous effusion confirmed by biochemical analysis. By five days after surgery in dogs with TD lacerations, and by 10 days after surgery in dogs with TD transections, thoracic effusion had ceased. Lymphangiography, performed seven days after resolution of thoracic effusion, showed TD patency only in the dogs with TD lacerations. The TD did not appear to be patent in dogs with TD transections. Histologically, in dogs with TD lacerations, one moderately dilated lymphatic vessel was seen at the surgical site in one animal and the thoracic duct and other lymphatics in the two other dogs appeared normal. Minimal perivascular accumulations of neutrophils, macrophages, and lymphocytes were present adjacent to two lymphatics in one animal. A mild increase in fibrous connective tissue and neovascularization was present in the adjacent subpleura. In dogs with complete transections, three to six dilated lymphatics were present at the transection site. Mild thickening of the tunica media was present in one thoracic duct, associated with a "J"-shaped area of condensed collagen, presumed to be a collapsed thoracic duct in one animal. Mild to moderate accumulations of macrophages, lymphocytes, and moderate neovascularization was present in the surrounding tissue, separating it from the underlying connective tissue.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMedDate not supplied

Evaluation of the Palmaz stent in the trachea and mainstem bronchi of normal dogs.

OBJECTIVE: This study evaluates the efficacy of the Palmaz balloon expandable intraluminal stent in the trachea and mainstem bronchi of normal dogs. STUDY DESIGN: Effects of the stent were evaluated by physical examination, thoracic radiography, respiratory tract fluoroscopy and endoscopy, tracheal diameter measurement, postmortem examination, and airway histomorphometry. ANIMALS OR SAMPLE POPULATION: Ten normal beagle dogs. METHODS: Stent size was estimated from thoracic radiographs in awake dogs. Group I dogs (n = 4) had two stents placed: one in the thoracic trachea (TT) plus a randomly chosen mainstem bronchus (MB). Group II dogs (n = 3) had stents placed in the MB (one stent), TT (one stent), and mid- or proximal cervical trachea (CT) (one or two stents). Three dogs were used as sham-operated controls (group III). Temperature, pulse, respiration, and cough were measured twice daily. Dogs were evaluated at 21 and 49 to 56 days after stent placement, euthanatized, and tissues were collected for histomorphometric analysis of stent integration and epithelial pathology. RESULTS: Mean tracheal diameters of awake (10.5 +/- 1.7 mm) and anesthetized dogs before stent implantation (13.9 +/- 2.0 mm) were significantly different (P < .01). Complications associated with stent placement included acute pulmonary edema (n = 2), stent migration (n = 7), stent collapse (n = 4 CT, 2 TT, and 1 MB), and positive tracheal culture (n = 10). Group II dogs coughed more at rest, exercise, and with tracheal palpation than dogs in other groups (P < .01). Group I dogs coughed more at rest than group III dogs (P < .01). Stent integration ranged from 0 to 91.3%. Squamous metaplasia and epithelial ulceration associated with stents ranged from 0 to 57.5% and 0 to 32.7%, respectively. CONCLUSIONS: Determination of stent size should be based on measurements taken on anesthetized dogs because use of inappropriately sized stents may promote stent migration, squamous metaplasia, and/or ulceration. Epithelialization over stent struts may occur if the stent is closely associated with tracheal epithelium. CLINICAL RELEVANCE: Palmaz stents do not appear to be appropriate for placement in the CT of dogs; however, with technical modifications, application in the TT and MB may be feasible.

Animals↗
PubMedDate not supplied

The efficacy of mechanical abrasion and talc slurry as methods of pleurodesis in normal dogs.

OBJECTIVE: To determine the efficacy of mechanical abrasion and talc slurry as methods for pleurodesis in normal dogs. STUDY DESIGN: Experimental study. ANIMALS OR SAMPLE POPULATION: Ten normal beagle dogs. METHODS: Group I dogs had mechanical abrasion (MA) of the pulmonary and costal pleurae performed in one hemithorax with a dry gauze sponge with a median sternotomy approach. Group II dogs had 100 mL of a 1 g talc slurry (TS) administered into one hemithorax through a tube thoracostomy. Administration of the TS was visualized by using video thoracoscopy. All dogs were evaluated at 2, 10, 20, and 30 days postoperatively by means of thoracic radiography and ultrasonographic thoracic wall measurement. The dogs were euthanatized 30 days postoperatively and a gross necropsy was performed. Hemithoraces were assigned a pleurodesis score (0-4) and an obliteration grade (0-6). Tissues were collected for histopathologic examination of pulmonary pleura, costal pleura, and pleural adhesions. Pulmonary and costal pleurae were graded for the degree of fibrosis (0-4). RESULTS: Obliteration grade and costal pleural fibrosis score were significantly higher for the treated sides in the MA dogs compared with the TS dogs. MA Dogs: Mechanical abrasion dogs had pleurodesis, obliteration, and pleural fibrosis scores that were greater on the treated side than the untreated side, however, the differences were not statistically significant. Only two MA dogs had firm adhesion of the pulmonary pleura to the costal pleura in portions of the cranial and middle lung lobes in the treated hemithorax. Thoracic wall surface area covered with adhesions was 15% and 21% in each of these two dogs. The median pulmonary pleural fibrosis score of all MA dogs for the treated hemithorax was 3 compared to 0 on the untreated side. TS Dogs: There was no statistical difference for pleurodesis scores and obliteration grades between the treated and untreated sides. No dogs showed evidence of pulmonary to costal pleural adhesions. Histopathology showed talc crossover into the untreated side in all five dogs. Median pulmonary fibrosis score of the treated hemithorax was 1 compared with 0 on the untreated side. CONCLUSIONS: Neither method of pleurodesis produced sufficient pleural adhesions to obliterate the pleural space. It is possible that the degree of pulmonary pleural fibrosis present in MA dogs may be sufficient to limit air leakage from pulmonary blebs and bullae resulting in successful treatment of spontaneous pneumothorax.

Animals↗
PubMedDate not supplied

Lymphedema. Clinical signs, diagnosis, and treatment.

Medical management of lymphedema is warranted in all dogs with suspected congenital lymphedema, before surgical intervention. Although pharmaceutical agents, such as the benzo-pyrones, have not been investigated for clinical use in dogs, such studies appear to be justified. None of the surgical techniques discussed will cure lymphedema. The only technique reported with any frequency in the dog has been excision of affected tissues, and although some successes have been reported with this procedure, others have found it to be of no benefit or severe complications have occurred. Excisional techniques require meticulous attention to prevent infection intraoperatively and postoperatively. Staging the procedure may decrease problems associated with devascularization of remaining tissues. Evaluation of other techniques may be warranted in dogs; however, no technique has proven to be consistently beneficial in human beings with lymphedema.

Animals↗
PubMedDate not supplied

Presumptive, iatrogenic gastric outflow obstruction associated with prior gastric surgery.

Iatrogenic gastric outflow obstruction in two dogs appeared to be caused by prior gastric surgery. The obstructions were believed to be anatomical rather than functional based on endoscopic examinations. Initially, the dogs had been evaluated and each had received two abdominal surgeries because of gastrointestinal bleeding, vomiting, or both. Eventually, both dogs were euthanized due to complications arising after attempted surgical correction of the iatrogenic obstructions. While gastric surgery commonly is performed, it seldom is considered to be a potentially harmful procedure. However, as these cases demonstrate, the decision to perform a gastrotomy must be weighed against possible risks and complications. Iatrogenic gastric outflow obstruction associated with surgery may be prevented by minimizing tissue inversion into the gastric lumen when surgery is performed near the pyloric outflow tract. Additionally, when large lesions near the pylorus are resected surgically, preservation of the continuity of the outflow tract is necessary.

Adenocarcinoma↗
PubMedDate not supplied

Successful treatment of uterine torsion and fetal retention in a postparturient Great Pyrenees bitch with septic peritonitis and prothrombotic complications.

The treatment and favorable outcome of a bitch with uterine torsion and two retained fetuses are described. The condition was corrected surgically by ovariohysterectomy. Complications (i.e., septic shock, peritonitis, and hemostatic abnormalities) were managed with aggressive medical therapy. Torsion of the gravid uterus in dogs is a life-threatening condition which can have a successful outcome if medical complications encountered in the pre- and postoperative periods are treated quickly and effectively.

Ampicillin↗
PubMedDate not supplied

Lymphangiosarcoma in a dog presenting with massive head and neck swelling.

A three-year-old, neutered male Chesapeake Bay retriever was presented for acute onset of severe, progressive swelling of the head, neck, and cranial trunk. Diffuse lymphangiosarcoma involving the superficial and deep dermis and subcutaneous tissue was observed on skin biopsies. Lymphangiosarcoma is a rarely reported tumor of the lymphatic system in dogs and cats. The importance of obtaining skin biopsies in animals with acute edema of unknown etiology is emphasized. Additionally, neoplasia should be considered as a potential diagnosis in a dog with an acute onset of edema.

Animals↗
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Thrombosis of the caudal vena cava presenting as an unusual cause of an abdominal mass and thrombocytopenia in a dog.

Thrombosis of the caudal vena cava in a dog secondary to metastatic neoplasia is described. The dog had a palpable abdominal mass and persistent thrombocytopenia due to a thrombosed caudal vena cava that was surgically removed. A few days after its removal, the dog died and neoplastic cells of neural crest origin were identified at the edge of the thrombus. Massive thrombosis can be an unusual cause of platelet consumption, leading to thrombocytopenia and disseminated intravascular coagulation. Deep vein thrombosis of the vena cava can occur in dogs and may mimic an abdominal mass. Multiple mechanisms may be involved in the development of venous thrombosis, including endothelial damage by neoplastic cells and the presence of a hypercoagulable state secondary to neoplasia. Extensive collateral circulation may allow removal of diseased vena cava.

Animals↗