Clarence A. Rawlings

Laparoscopic-assisted gastropexy.

Gastropexy is the term for a surgical procedure to attach the stomach to the body wall effectively preventing the stomach from twisting. Dogs that have had a gastropexy can still develop a dilated and gas filled stomach but the life threatening twist is very rare. Recently, surgical techniques have been developed which allow a gastropexy to be performed with laparoscopy. The benefits of a laparoscopic-assisted gastropexy include: ♦ Less pain since the surgery is done with 2 small incisions only ♦ Shorter surgery and anesthesia time ♦ Quick recovery ♦ Patient can go home the day of the surgery ♦ Reduced surgical complication rate over open techniques ♦ Less expensive than treating life threatening GDV

Thoracoscopic Thoracic Duct Ligation and Thoracoscopic Pericardectomy for Treatment of Chylothorax in Dogs

OBJECTIVE To report the use of thoracoscopic thoracic duct ligation (TDL) and pericardectomy for treatment of chylothorax. STUDY DESIGN Case series. ANIMALS Dogs with chylothorax (n=12). METHODS Dogs with secondary or idiopathic chylothorax had thoracoscopy performed in sternal recumbency through 3 portals in the caudal right hemithorax for TDL and were then repositioned in dorsal recumbency for pericardectomy. Portals were placed in the 5th and 7th intercostal spaces of the right hemithorax with 1 transdiaphragmatic portal in the right paraxiphoid position. Follow-up was performed by recheck examination or telephone interview to determine outcome. RESULTS Seven dogs (58%) had idiopathic chylothorax; 6 dogs (85.7%) had complete resolution of their effusion, whereas only 2 of the 5 nonidiopathic dogs (40%) had complete resolution. CONCLUSIONS Thoracoscopy is minimally invasive, provides excellent observation, and allows for ligation of the thoracic duct in the caudal thorax. Patients with idiopathic chylothorax may have a better prognosis after TDL and pericardectomy than dogs with nonidiopathic chylothorax. CLINICAL RELEVANCE Thoracoscopy for ligation of the thoracic duct and pericardectomy is an acceptable surgical technique for treatment of chylothorax.

Further development of the baboon as a model for acute schistosomiasis.

Baboons develop a syndrome, including eosinophilia and transient fever, after infection with cercariae of Schistosoma mansoni that is consistent with the human syndrome of acute schistosomiasis. Radiotelemetry can be used to follow the course of fever in infected baboons. Individual variations in intensity of disease were noted in baboons. These symptoms and signs were more closely linked to the onset of oviposition by the newly matured worms than they were to the presence of migrating schistosomula or maturing worms. The baboon is concluded to be a suitable and useful model for human acute schistosomiasis mansoni.

Cystoscopic diagnosis and treatment of ectopic ureters in female dogs: 16 cases (2005-2008)

OBJECTIVE To determine outcome of cystoscopic-guided transection for treatment of ectopic ureters in dogs. DESIGN Retrospective case series. ANIMALS 16 female dogs. PROCEDURES Medical records of dogs that underwent cystoscopic-guided transection of the membrane separating unilateral or bilateral ectopic ureters from the urethra and bladder between May 2005 and May 2008 were reviewed. Postoperative outcome was determined by use of telephone interviews conducted 1 to 36 months after the procedure. RESULTS 4 dogs had complete resolution of urinary incontinence with cystoscopic-guided transection alone, an additional 5 dogs had complete resolution with a combination of cystoscopic-guided transection and phenylpropanolamine administration, and an additional 4 dogs had an improvement in urinary control, although urinary incontinence persisted. Outcome could not be assessed in the remaining 3 dogs because of collagen injections in the urethra at the time of ureteral transection (n = 2) or nephrectomy secondary to unilateral hydronephrosis (1). CONCLUSIONS AND CLINICAL RELEVANCE Results suggested that cystoscopic-guided transection may be an acceptable alternative to traditional surgical correction of ectopic ureter in dogs. Most complications associated with the cystoscopic procedure were minor and easily managed.

Resection of inflammatory polyps in dogs using laparoscopic-assisted cystoscopy.

Inflammatory polyps in the urinary bladder of two dogs were removed via laparoscopic-assisted cystoscopy. In addition, one dog had a calculus removed and liver biopsies taken using the same two trocar sites. The laparoscopic-assisted cystoscopic technique provided clear surgical margins and permitted a thorough examination of the inside of the bladder and urethra. The technique was minimally invasive, produced little abdominal injury, and limited urine contamination of the abdomen.

Tumor necrosis factor production in cats in response to lipopolysaccharide: an in vivo and in vitro study

Supernatants from feline peritoneal exudate cells (PECs) exposed to lipopolysaccharde (LPS) produced significantly (P < 0.05) more tumor necrosis factor (TNF) activity than supernatants from cells exposed to media. An in vitro LPS response was obtained following incubation of whole blood with 10 micrograms ml-1 LPS for 2 h. Intravenous infusion of LPS (750 micrograms kg-1 rapidly increased plasma TNF activity to a maximum at 60 min after initiation of LPS infusion. By 180 min, TNF activity returned to baseline. Cats produce TNF in response to LPS in a manner similar to other species. Measurement of TNF activity in plasma or in LPS-stimulated whole blood are methods to further characterize the inflammatory response in feline diseases.

Pulmonary Arteriography and Hemodynamics During Feline Heartworm Disease

The ability of aspirin to block arterial disease and thromboembolism of the pulmonary arteries was studied in heartworm-infected cats. Three groups of cats were transplanted with four heartworms per cat and studied. One group of eight cats (aspirin group) received aspirin (97.5 mg, twice a week) for the five-month infection and another group of eight cats served as the nontreated control group (nontreated group). Based upon the results of the first two groups, the third group (adjusted aspirin group) of six cats was studied in which the aspirin dosage was adjusted in order to maintain an inhibition of in vitro platelet aggregation. Cats were studied by nonselective pulmonary arteriograms before heartworm transplantation and by selective arteriograms, aortograms, and pulmonary hemodynamics five months after heartworm transplant. Pulmonary hypertension, (mean pulmonary artery pressures > 16 mmHg), was discovered in three cats with one cat in each group. There were no differences in the mean pulmonary artery pressure or vascular resistance between the groups. Many of the arterial diameters for the nontreated and aspirin groups were greater after the five-month infection than before heartworm infection. All of the postinfection caudal arteries were tortuous and had aneurysms. Some of the caudal lung lobes had perfused areas that appeared to have a hypervascular microvasculature. The proportion of obstructed right and left distal caudal pulmonary arteries and the resulting nonperfused area of the caudal lung lobe in the nontreated and aspirin treated groups were each greater than in the adjusted aspirin group. Prominent bronchial arteries and arterial circulation were present in three of six of the nontreated cats, five of seven of the aspirin-treated cats, and two of five adjusted aspirin cats, that had diagnostic aortograms. Aspirin given at a standard dosage of 97.5 mg twice a week did not reduce the arteriographically demonstrated arterial disease, the pulmonary hypertension, or the obstruction of caudal lobar arteries by thromboembolism and exuberant villiis proliferation. The adjusted aspirin dosage, which required daily administration in some cats, appeared to have limited benefits. Since this dosage was individualized for each cat and near the toxic dosage for cats, we are reluctant to recommend aspirin in cats with heartworm disease. Nonselective pulmonary arteriograms, as done in this study, can be useful in cats with suspected heartworm infection and radiographic signs, but which have negative test results for microfilaria and ELISA-antigen.

A Histopathological Comparison of Two Techniques for Soft Palate Resection in Normal Dogs

Eighteen dogs were used to compare histopathological findings following excision of the soft palate using either a bipolar sealing device or a carbon dioxide laser. Histopathological comparisons were done at 48 and 96 hours after soft palate resection. Mean depths of tissue injury at 96 hours were 3.5 and 3.33 mm for bipolar sealing device and carbon dioxide laser, respectively. Control of hemorrhage was excellent in all dogs, and none of the dogs developed signs of respiratory compromise after soft palate resection. Using the bipolar sealing device for soft palate resection was significantly faster than using the carbon dioxide laser, although both techniques were fast.

Morphologic Changes in the Lungs of Cats Experimentally Infected With Dirofilaria immitis

The morphologic response of the pulmonary arteries and lungs in cats was studied after a five month heartworm infection produced by transplantation of four adult heartworms/cat. One group of seven heartworm infected cats was not treated, another group of seven cats was treated with 97.5 mg of aspirin given twice a week, and the third group of six cats was given aspirin at a sufficient dosage to block in vitro platelet aggregation throughout the study. A fourth group of eight noninfected cats served as controls. Five months after heartworm infection, the cats were euthanized and the lungs perfusion fixed for light microscopy and scanning electron microscopy of the pulmonary arterial surfaces. All cats in the three heartworm-infected groups had live heartworms and the typical pulmonary arterial changes of heartworm disease at necropsy. The arterial surfaces, as viewed with scanning electron microscopy, had villus proliferations that were more numerous and exuberant than similar infections in dogs. Mean percentage of arterial surface involvement with villus proliferation of the nontreated heartworm infected cats was 67.3%; the aspirin treated cats, 73.8%; and the adjusted aspirin treated cats, 75.9%. The villi were myointimal proliferations in the small and medium-sized arteries. The more elastic arteries had a predominance of fibromuscular proliferation. All heartworm infected cats had arterial muscular hypertrophy of the small arteries, in contrast to only three of eight of the nonheartworm infected cats. The caudal lobar arteries were frequently obstructed with either villus proliferation, thrombi, and/or dead heartworms. The muscular arteries had branches with marked dilation, a condition associated with pulmonary hypertension in man. However, only three cats, one in each group, had pulmonary hypertension. The adjusted aspirin group had less arteriosclerosis and thrombosis than the other two heartworm-infected groups. There were no statistical differences between the heartworm groups with respect to arterial muscular hypertrophy, myointimal proliferation with and without eosinophilia, vein-like dilations of the muscular arterial branches, and percentage of arterial surface with villus proliferation. Aspirin, when given at platelet inhibiting doses, reduced only a portion of the pulmonary response to heartworms in these cats. It was presumed that the inflammatory response to heartworms in the cat is so severe that trophic factors other than those released by platelets can also produce arterial disease. Based upon this study, aspirin is not recommended for heartworm disease in the cat.

THE FECUNDITY OF SCHISTOSOMA MANSONI IN CHRONIC NONHUMAN PRIMATE INFECTIONS AND AFTER TRANSPLANTATION INTO NAIVE HOSTS

Adult Schistosoma mansoni worms were transplanted from 8 nonhuman primates with chronic infections into 8 naive recipients, in an effort to test the hypothesis that worm fecundity reduction in chronic infections is the result of host immunity or some other host effect. Techniques for perfusing living donors without the added use of anti-schistosomal drugs and for reducing the likelihood of post-operative bacterial endotoxemia and septic shock are described. Fecundity values in terms of eggs per day per female worm were obtained for the worms in their original and in their new hosts and compared. In 3 experiments, perfusions were incomplete and the donors were saved, enabling direct comparisons of fecundity to be made in subpopulations of worms in both their original and new hosts, after equal life spans. In only 1 of the 8 transplantations was there a clear increase in fecundity after surgical introduction into a naive host. Therefore, these experiments fail to support the hypothesis that reduced fecundity of S. mansoni worms in permissive nonhuman primate hosts is a reversible result of host immunity or some other host-derived factor. Despite this negation, further evidence for reduced worm fecundity in older infections was obtained. In the absence of in vivo evidence for immune-mediated antifecundity, worm senescence is the most likely explanation for this finding, with irreversible immune damage to the worms being a less attractive alternative hypothesis.