Sarcocystis neurona Encephalitis in a Dog

A 1.5–year-old male Feist dog was presented to a veterinarian for reluctance to stand on the hind legs. Treatment included dexamethasone and resulted in a favorable initial response, but posterior paresis returned and progressed to recumbency, hyperesthesia, and attempts to bite the owner. The dog was euthanized. The brain was negative for rabies by fluorescent antibody analysis. Multiple foci of encephalitis were found in the cerebrum and particularly in the cerebellum. Protozoa morphologically consistent with Sarcocystis sp. were identified at sites of intense inflammation and malacia. Additionally, multiple schizonts were identified in areas without inflammation. Immunohistochemistry using both polyclonal and monoclonal antibodies specific for Sarcocystis neurona was strongly positive. No reaction to polyclonal antisera for Toxoplasma gondii or Neospora caninum was found. Polymerase chain reaction confirmed that the protozoa were S. neurona. Additional aberrant hosts for S. neurona other than horses have been identified, but S. neurona encephalitis has not been documented previously in the dog.

Fatal Canid Herpesvirus 1 Respiratory Infections in 4 Clinically Healthy Adult Dogs

Four healthy adult dogs (Golden Retrievers aged 6 years and 9 years, Dalmatian aged 13 years, and Mastiff aged 5 years) developed clinical signs of acute respiratory disease and died within 2 to 7 days of onset of clinical signs. The lungs of the 3 dogs submitted for necropsy were diffusely and severely reddened due to hyperemia and hemorrhage. Microscopic lesions in all dogs were suggestive of acute viral or toxic respiratory damage and varied from acute severe fibrinonecrotic or hemorrhagic bronchopneumonia to fibrinous or necrotizing bronchointerstitial pneumonia. Necropsied dogs also had hemorrhagic rhinitis and tracheitis with necrosis. Virus isolation, transmission electron microscopy, and polymerase chain reaction were used to confirm the presence of canid herpesvirus 1 (CaHV-1) in the lung samples of these dogs. Lung tissues were negative for influenza A virus, canine distemper virus, canine parainfluenza virus, canine respiratory coronavirus, and canine adenovirus 2. Canid herpesvirus 1 has been isolated from cases of acute infectious respiratory disease in dogs but has only rarely been associated with fatal primary viral pneumonia in adult dogs. The cases in the current report document lesions observed in association with CaHV-1 in 4 cases of fatal canine herpesvirus pneumonia in adult dogs.

The equine cervical spine: comparing MRI and contrast-enhanced CT images with anatomic slices in the sagittal, dorsal, and transverse plane

BACKGROUND

The impact of cervical pathology on performance is of great importance to the horse industry. Accurate diagnosis of cervical disease with imaging modalities, including computed tomography (CT) and magnetic resonance imaging (MRI), requires thorough appreciation of normal cervical anatomy.

OBJECTIVES

(1) To describe in detail the anatomy of the equine cervical spine by comparing anatomical sections with corresponding MR and contrast-enhanced CT images in the sagittal, dorsal, and transverse plane. (2) To discuss the ability of MR and contrast-enhanced CT imaging to visualize anatomical structures in the cervical spine.

ANIMALS AND METHODS

Three cervical spines of young adults (3-8 years), collected immediately after humane euthanasia, were used. The spine was stabilized on a frame in a natural flexed position with an angle of 20°. MR and contrast-enhanced CT imaging was performed within six hours after euthanasia. Anatomical sections of 1 cm were made in the sagittal, dorsal, and transverse plane and compared with corresponding CT and MR images. The intervertebral disk thickness, facet joint angle, sagittal dural space diameter and ventromedial facet joint projection were quantified.

RESULTS

The anatomic location of clinically important structures including the facet joints, spinal cord, cervical nerve roots and intervertebral disks were reliably identified in the anatomical sections and their corresponding MR images. Contrast-enhanced CT images depicted all osseous borders, whereas MR images were superior for soft tissue structures.

CONCLUSION AND CLINICAL IMPORTANCE

This study enhances our understanding of normal cervical spine anatomy and the diagnostic usefulness of cervical MRI and contrast-enhanced CT in the horse.

Histological and computed tomographic evaluation of a parasitic conjoined twin in hybrid catfish (Ictalurus punctatus [Rafinesque] X Ictalurus furcatus [Lesueur])

There is growing use of hybrid catfish (Ictalurus punctatus ♀ X Ictalurus furcatus ♂) in commercial aquaculture to utilize hybrid vigour to improve production A conjoined twin specimen found during the course of production studies by the United States Department of Agriculture Catfish Genetic Research Unit (USDA-CGRU) was submitted to the Aquatic Research and Diagnostic Laboratory (ARDL). After preliminary inspection, it was transported to Mississippi State University, College of Veterinary Medicine for further evaluation. The specimen was examined using both computed radiography and computed tomography antemortem. Following humane euthanasia, the specimen was examined both grossly and histologically. Tissues from both fish were also submitted for genetic analysis to determine whether twins were derived from the same egg. This report records the presentation and examination of a pair of conjoined hybrid catfish (I. punctatus X Ictalurus furcatus).

Sarcocystis neurona schizonts-associated encephalitis, chorioretinitis, and myositis in a two-month-old dog simulating toxoplasmosis, and presence of mature sarcocysts in muscles

Sarcocystis neurona is an unusual species of the genus Sarcocystis. Opossums (Didelphis virginianus, D. albiventris) are the definitive hosts and several other species, including dogs, cats, marine mammals, and horses are intermediate or aberrant hosts. Sarcocysts are not known to form in aberrant hosts. Sarcocystis neurona causes fatal disease in horses (Equine Protozoal Myeloencephalitis, EPM). There are numerous reports of fatal EPM-like infections in other species, usually with central nervous system signs and associated with the schizont stage of S. neurona. Here, we report fatal disseminated S. neurona infection in a nine-week-old golden retriever dog from Mississippi, USA. Protozoal merozoites were identified in smears of the cerebrospinal fluid. Microscopically, lesions and protozoa were identified in eyes, tongue, heart, liver, intestines, nasal turbinates, skeletal muscle and brain, which reacted intensely with S. neurona polyclonal antibodies. Mature sarcocysts were seen in sections of muscles. These sarcocysts were ultrastructurally similar to those of S. neurona from experimentally infected animals. These data suggest that the dog is another intermediate host for S. neurona. Data suggest that the dog was transplacentally infected.

Canine Synovial Myxoma

This report describes the signalment, clinical findings, gross appearance, histological and immunohistochemical characteristics, and behavior of 39 cases of canine synovial myxoma. Large-breed middle-aged dogs—especially, Doberman Pinschers and Labrador Retrievers—were most commonly affected. The stifle and digit were the most common sites. Grossly, the tumors were composed of gelatinous nodules that often filled the joint cavity and exuded viscous fluid on cut section. In 12 cases (31%), radiographic bony lysis or grossly invasive growth was noted clinically. Histologically, the nodules were sparsely cellular and composed of stellate to spindle cells suspended in an abundant myxomatous matrix. By immunohistochemistry, the cells were positive for vimentin, heat shock protein 25, and cadherin 11 and negative for cytokeratin and S100 protein; some cells (20–40%) were positive for CD18. Affected dogs had long survival times (average, 2.5 years), even with incomplete excision of the tumor. Three cases had local recurrence, but none metastasized or directly resulted in death. Canine synovial myxoma is a histologically distinctive tumor with a good prognosis.

Leucocytoclastic vasculitis associated with Staphylococcus intermedius in the pastern of a horse

A pregnant quarterhorse mare became acutely lame as a result of severe swelling of its right hind leg, thought to have been caused by a fracture or a muscle tear. Diagnostic procedures ruled out a traumatic musculoskeletal cause and a physical examination revealed chronic pastern dermatitis ('scratches'/'grease heel'). Histopathological evaluation of biopsy samples from the right hind leg was consistent with a leucocytoclastic vasculitis, and culture yielded Staphylococcus intermedius. The treatment and infectious causes of pastern dermatitis are discussed.

Congenital hepatoblastoma in a neonatal alpaca cria

A neonatal alpaca cria found to have minimal clinical abnormalities was diagnosed postmortem with an epithelial-type hepatoblastoma with combined embryonal and fetal patterns, based on previously reported morphological features. Camelid neoplasia and domestic animal hepatoblastomas are very rare, with only a single case of congenital hepatoblastoma in a domestic animal previously reported.

Postoperative radiotherapy for canine soft tissue sarcoma

Thirty-five dogs with 37 soft tissue sarcoma tumors that were incompletely excised and treated with radiotherapy in the postoperative, adjuvant setting were reviewed. Variables evaluated included age, sex, tumor site, tumor histology, total tumor radiation dose, radiotherapy field size. time to recurrence, and survival. The majority of tumors were fibrosarcomas and hemangiopericytomas, but small numbers of other tumor types were also represented. Total tumor radiation dose ranged from 42 to 57 Gy given in 3- to 4.2-Gy daily fractions on a Monday through Friday schedule. Overall median survival was 1,851 days. Median time to local recurrence was greater than 798 days. Soft-tissue sarcoma tumors at oral sites had a statistically significant lower median survival (540 days) as compared to other tumor sites (2,270 days). Radiotherapy may be a useful adjuvant therapy for incompletely excised soft-tissue sarcomas with a reasonable expectation for long-term patient survival.

The effect of monopolar radiofrequency energy on partial-thickness defects of articular cartilage

PURPOSE

To evaluate the effect of monopolar radiofrequency (RF) energy on partial-thickness defects of articular cartilage, comparing the outcome of partial-thickness defects treated with monopolar RF energy with that of treatment by conversion of partial-thickness defects to full-thickness defects by curettage and microfracture.

TYPE OF STUDY

Randomized trial using adult female sheep.

MATERIALS AND METHODS

Thirty-six sheep were used in this study. Both stifles in each animal were randomly assigned to 1 of the following 3 procedures: (1) partial-thickness defect without any treatment to serve as a sham-operated control, (2) partial-thickness defect with RF energy treatment, and (3) partial-thickness defect treated by conversion of the defect to a full-thickness defect by curettage and microfracture. Nine sheep were euthanized at 0, 2, 12, and 24 weeks after surgery (n = 6 per group). After euthanasia, cartilage samples were harvested from the defect sites, and chondrocyte viability was analyzed by confocal laser microscopy using a triple-labeling technique. Cartilage samples also were decalcified and stained with hematoxylin and eosin and safranin-O for histologic analysis. Surface properties of cartilage samples were analyzed using scanning electron microscopy.

RESULTS

The analysis of chondrocyte viability showed that RF treatment caused death of almost all chondrocytes in the defect. Histologic analysis showed that RF treatment caused detrimental effects to chondrocytes and proteoglycan concentration that progressed over time, and that full-thickness defects were repaired by fibrocartilage by 24 weeks after surgery. Scanning electron microscopy analysis indicated that RF-treated groups were significantly smoother and less irregular than control groups at 2, 12, and 24 weeks after surgery.

CONCLUSIONS

This study showed that monopolar RF energy caused long-term damage to cartilage in this sheep model and did not appear to have the beneficial effects reported in a previous study that evaluated application of this technique using a bipolar RF probe.

Effect of nonablative laser energy on the joint capsule: an in vivo rabbit study using a holmium:YAG laser

BACKGROUND AND OBJECTIVE

The nonablative application of holmium:yttrium-aluminum-garnet (Ho:YAG) laser energy to the joint capsule of patients with glenohumeral instability has been found to shrink capsular tissue and to help stabilize the joint. The purpose of this study was to evaluate the effect of nonablative laser energy on the short-term histological properties of joint capsular tissue in an in vivo rabbit model.

STUDY DESIGN/MATERIALS AND METHODS

Eighteen mature New Zealand white rabbits were used in this study. One randomly selected stifle was treated with laser energy, and the contralateral stifle was sham-operated. Animals were euthanized immediately after surgery (day 0), at 7 days postsurgery and 30 days postsurgery. Specimens were processed for histology and transmission electron microscopy.

RESULTS

Laser-treated samples at day 0 showed diffuse hyalinization of collagen with nuclear karyorrhexis of fibroblasts. Laser-treated tissue at 7 days postsurgery revealed fibroblast proliferation around and into acellular hyalinized regions of collagen. At 30 days postlaser treatment, areas of fused collagen were greatly reduced as large reactive fibroblasts migrated and secreted matrix.

CONCLUSION

This study illustrates the short-term in vivo tissue response to nonablative laser treatment, where acellular hyalinized regions of collagen are infiltrated by fibroblasts that have used the treated collagen as the framework for migration and secretion of new collagen matrix in order for tissue repair to proceed.

The biologic response to laser thermal modification in an in vivo sheep model

The purpose of this study was to evaluate the effect of nonablative laser energy on mechanical, histologic, ultrastructural, and biochemical properties of joint capsular tissue in an in vivo sheep model. Femoropatellar joint capsule was treated with the holmium:yttrium-aluminum-garnet laser via an arthroscope, and tissues were harvested immediately after surgery, or at 3, 7, 14, 30, 60, 90, and 180 days after surgery (n = 8/group). Laser treatment caused significant decreases in tissue stiffness from 0 to 7 days after surgery, then stiffness gradually increased after 14 days. Tissue strength was lowest 3 days after laser treatment. Histologic examination revealed immediate collagen hyalinization and cell necrosis, followed by active cellular response characterized by extensive fibroblast migration and capillary sprouting. Tissue appeared to be normal histologically 60 days after surgery; however, collagen fibrils remained uniformly small. This study showed an active tissue response secondary to thermal modification with concomitant recovery of mechanical properties by 30 days after surgery. Whether the shrinkage or joint stability was maintained with time remains to be evaluated. To clarify the advantages and disadvantages of this technique, a carefully controlled clinical trial with long term followup should be performed.

The effects of indwelling transurethral catheterization and tube cystostomy on urethral anastomoses in dogs

The influence of urinary diversion procedures on urethral healing was studied in 15 male dogs following transection and anastomosis of the intrapelvic portions of their urethras. Dogs were randomly assigned to one of three treatment groups and had urine diverted from the surgical site by indwelling transurethral catheter, cystostomy catheter, or a combination of transurethral catheter and cystostomy catheter. There were no statistically significant differences in urethral healing when considering the different diversion methods, based on clinical, radiographic, and urodynamic parameters evaluated.

Biological heterogeneity, including systemic replication in mice, of H5N1 influenza A virus isolates from humans in Hong Kong

An H5N1 avian influenza A virus was transmitted to humans in Hong Kong in 1997. Although the virus causes systemic infection and is highly lethal in chickens because of the susceptibility of the hemagglutinin to furin and PC6 proteases, it is not known whether it also causes systemic infection in humans. The clinical outcomes of infection in Hong Kong residents ranged widely, from mild respiratory disease to multiple organ failure leading to death. Therefore, to understand the pathogenesis of influenza due to these H5N1 isolates, we investigated their virulence in mice. The results identified two distinct groups of viruses: group 1, for which the dose lethal for 50% of mice (MLD50) was between 0.3 and 11 PFU, and group 2, for which the MLD50 was more than 10(3) PFU. One day after intranasal inoculation of mice with 100 PFU of group 1 viruses, the virus titer in lungs was 10(7) PFU/g or 3 log units higher than that for group 2 viruses. Both types of viruses had replicated to high titers (>10(6) PFU/g) in the lungs by day 3 and maintained these titers through day 6. More importantly, only the group 1 viruses caused systemic infection, replicating in nonrespiratory organs, including the brain. Immunohistochemical analysis demonstrated the replication of a group 1 virus in brain neurons and glial cells and in cardiac myofibers. Phylogenetic analysis of all viral genes showed that both groups of Hong Kong H5N1 viruses had formed a lineage distinct from those of other viruses and that genetic reassortment between H5N1 and H1 or H3 human viruses had not occurred. Since mice and humans harbor both the furin and the PC6 proteases, we suggest that the virulence mechanism responsible for the lethality of influenza viruses in birds also operates in mammalian hosts. The failure of some H5N1 viruses to produce systemic infection in our model indicates that multiple, still-to-be-identified, factors contribute to the severity of H5N1 infection in mammals. In addition, the ability of these viruses to produce systemic infection in mice and the clear differences in pathogenicity among the isolates studied here indicate that this system provides a useful model for studying the pathogenesis of avian influenza virus infection in mammals.

Massive Dracunculus insignis infection in a dog

An 11-year-old 13-kg (28.6-lb) spayed female Cocker Spaniel was examined because of subcutaneous nodules on the hind limbs and ventral aspects of the thorax and abdomen. Focal areas of erythema and pyoderma were associated with the nodules, and purulent exudate could be expressed from a fistula in the nodules. A nematode approximately 20.5 cm in length was isolated from a draining fistula in 1 nodule and identified as Dracunculus insignis. The dog was treated with ivermectin, fenbendazole, and metronidazole, but the owner was still able to recover worms from multiple nodules for the next year.

The thermal effect of monopolar radiofrequency energy on the properties of joint capsule. An in vivo histologic study using a sheep model

The purpose of this in vivo study was to analyze the short-term tissue response of joint capsule to monopolar radiofrequency energy and to compare the effects of five power settings at 65 degrees C on heat distribution in joint capsule. In 12 mature Hampshire sheep, the medial and lateral aspects of both stifles were treated with monopolar radiofrequency energy under arthroscopic control in a single uniform pass to the synovial surface. The radiofrequency generator power settings were 0, 10, 15, 20, 25, and 30 watts (N = 8/group). The electrode tip temperature was 65 degrees C. Histologic analysis at 7 days after surgery revealed thermal damage of capsule at all radiofrequency power settings. The lesion's cross-sectional area, depth, vascularity, and inflammation were commensurate with radiofrequency power. Tissue damage was indicated by variable inflammatory cell infiltration, fusion of collagen, pyknosis of fibroblasts, myonecrosis, and vascular thrombosis, whereas synovial hyperplasia, fibroblast proliferation, and rowing of sarcolemmal nuclei demonstrated regenerative processes. This study revealed that radiofrequency power settings and heat loss through lavage solution play a significant role in heat distribution and morphologic alterations in joint capsule after arthroscopic application of monopolar radiofrequency energy.

Orbital lymphosarcoma associated with reticuloendotheliosis virus in a peafowl

Lymphosarcoma associated with infection by avian reticuloendotheliosis virus was diagnosed in an Indian peafowl with exophthalmia and exposure keratitis. Exenteration of the orbit was complicated by a profound oculocardiac reflex and extensive hemorrhage during surgery. Orbital bleeding was controlled by direct pressure, electrocautery, topical administration of bovine thrombin, and application of sterile gelatin sponges and oxidized regenerated cellulose. A blood transfusion was also performed. In addition to describing methods of handling intraoperative complications of orbital exenteration in birds, to the authors' knowledge, this is the first report to describe an association of reticuloendotheliosis virus, which more commonly affects poultry, with lymphosarcoma in an Indian peafowl.

Sonographic renal findings in 20 dogs with leptospirosis

Abdominal ultrasound examinations of 20 dogs with confirmed leptospirosis were reviewed retrospectively for renal abnormalities. Three dogs had a normal ultrasound examination. The remaining 17 dogs had sonographic abnormalities of the kidneys. These abnormalities, seen either alone or in combination, included renalmegaly (n=10), pyelectasia (n=9), increased cortical echogenicity (n=15), perinephric effusion (n=5), and a medullary band of increased echogenicity (n=6). At our institution, the medullary band of increased echogenicity has only been seen in dogs with leptospirosis and may therefore be a specific sonographic sign for this disease.

Efficacy of pyridoxine to ameliorate the cutaneous toxicity associated with doxorubicin containing pegylated (Stealth) liposomes: a randomized, double-blind clinical trial using a canine model

A cutaneous reaction termed palmar-plantar erythrodysesthesia (PPES) or hand-foot syndrome can be dose limiting for Doxil, a doxorubicin containing pegylated (Stealth) liposome. The objective of this study was to determine the ability of concomitant pyridoxine therapy to prevent the development of PPES during Doxil therapy. Forty-one dogs with non-Hodgkin's lymphoma were randomized in a double-blind fashion to receive either oral pyridoxine or placebo daily during Doxil chemotherapy (1.0 mg/kg, i.v., every 3 weeks for a total of five treatments). Cutaneous toxicity was determined by clinical and histological scoring. No difference was observed in remission rates (71.4 versus 75%) achieved between groups. The likelihood of developing serious PPES and having to decrease or discontinue Doxil therapy was 4.2 times (relative risk) greater in placebo group dogs than in pyridoxine group dogs (P = 0.032). Pyridoxine did not completely abrogate PPES; however, it occurred later and less dramatically than in placebo-treated dogs and resulted in fewer treatment delays or discontinuations, allowing a higher cumulative dose of Doxil to be received. Compared to the 5.0 mg/kg cumulative target dose, pyridoxine-treated dogs received a median cumulative dose of 4.7 mg/kg (mean, 4.1 mg/kg), and the placebo-treated dogs received a median of 2.75 mg/kg (mean, 2.9 mg/kg; P < 0.028). A trend (P = 0.084) toward prolongation of remission length was observed in dogs receiving pyridoxine, which was likely attributable to their ability to receive more Doxil without delay or discontinuation. We conclude that pyridoxine is effective in delaying the onset and severity of PPES in this canine model.

The effect of thermal heating on the length and histologic properties of the glenohumeral joint capsule

The purpose of this study was to evaluate the effect of temperature on shrinkage and the histologic properties of glenohumeral joint capsular tissue. Six fresh-frozen cadaveric shoulders were used for this study. Seven joint capsule specimens were taken from different regions from each glenohumeral joint and assigned to one of seven treatment groups (37 degrees, 55 degrees, 60 degrees, 65 degrees, 70 degrees, 75 degrees, 80 degrees C) using a randomized block design. Specimens were placed in a tissue bath heated to one of the designated temperatures for 10 minutes. Specimens treated with temperatures at or above 65 degrees C experienced significant shrinkage compared with those treated with a 37 degrees C bath. The posttreatment lengths in the 70 degrees, 75 degrees, and 80 degrees C groups were significantly less than the pretreatment lengths. Histologic analysis revealed significant thermal alteration characterized by hyalinization of collagen in the 65 degrees, 70 degrees, 75 degrees, and 80 degrees C groups. This study demonstrated that temperatures at or above 65 degrees C caused significant shrinkage of glenohumeral joint capsular tissue. These results are consistent with histologic findings, which revealed significant thermal changes of collagen in the 65 degrees, 70 degrees, 75 degrees, and 80 degrees C groups. To verify the validity of laser application for shrinkage of joint capsule, studies designed to compare these findings with the effects of laser energy must be performed.

Preclinical trial of doxorubicin entrapped in sterically stabilized liposomes in dogs with spontaneously arising malignant tumors

PURPOSE

To prospectively evaluate the short-term toxicoses associated with pegylated-liposomal doxorubicin (Doxil) administered to dogs with measurable tumors of various histologic types and sites. Preliminary information regarding efficacy was also generated.

METHODS

A group of 51 dogs with histologically confirmed malignancies received a total of 103 Doxil treatments given i.v. every 3 weeks at dosages ranging from 0.75 to 1.1 mg/kg in the context of a phase I dose-escalation trial. Acute and short-term toxicities as well as tumor response and duration of response were characterized.

RESULTS

The maximally tolerated dose in tumor-bearing dogs was established as 1.0 mg/kg i.v. every 3 weeks. The dose-limiting toxicity was a cutaneous toxicity clinically resembling palmar-plantar erythrodysesthesia (PPES). An overall response rate of 25.5% was observed with five complete responders and eight partial responders.

CONCLUSIONS

Doxil appeared to be well tolerated at dosages similar to those tolerated for free doxorubicin in tumor-bearing dogs. PPES was the dose-limiting toxicity encountered, rather than myelosuppresion as is the case with free doxorubicin in dogs. Doxil as a single agent may have a broad spectrum of activity and deserves further evaluation.

SK&F 86002, a dual cytokine and eicosanoid inhibitor, attenuates endotoxin-induced cardiopulmonary dysfunction in the pig

Cytokines and eicosanoids are well documented important mediators of endotoxemia. Bicyclic imidazoles are a novel class of nonsteroidal anti-inflammatory compounds that display unique pharmacological profiles by reducing cytokine production and arachidonic acid metabolism. In this study, we evaluated the ability of the bicyclic imidazole, SK&F 86002, to attenuate endotoxin-induced cardiopulmonary dysfunction. Pigs were randomly assigned to one of four groups: LPS (n = 5), given .5 microgram/kg/h 055:B5 Escherichia coli lipopolysaccharide (LPS) intravenously (i.v.) for 6 h; saline (n = 5); SK&F 86002 (n = 3), given 50 mg/kg SK&F 86002 orally 30 min prior to anesthesia; and SK&F 86002 + LPS (n = 5). Administration of LPS resulted in cardiopulmonary dysfunction characterized by decreased stroke volume and arterial oxygen tension, and increased room air alveolar-arterial oxygen gradient, pulmonary arterial pressure, pulmonary vascular resistance, and peak intratracheal pressure. Additionally, LPS administration was associated with leukopenia and increased pulmonary myeloperoxidase activity. Pretreatment with SK&F 86002 attenuated LPS induced hypotension, hypoxemia and bronchoconstriction and blocked the pulmonary hypertension. SK&F 86002 blocked the LPS-induced increase in myeloperoxidase activity, indicating a reduction in pulmonary neutrophil infiltration, but had no effect on systemic leukopenia. Pretreatment with SK&F 86002 significantly attenuated LPS-induced increases in plasma thromboxane B2 and tumor necrosis factor-alpha. We hypothesize that ameliorating effects of SK&F 86002 in this endotoxin model of cardiopulmonary dysfunction are related to inhibition of cytokine and eicosanoid biosynthesis.

The effect of nonablative laser energy on joint capsular properties. An in vitro histologic and biochemical study using a rabbit model

The purpose of this study was to evaluate the effect of laser energy at nonablative levels on joint capsular histologic and biochemical properties in an in vitro rabbit model. The medial and lateral portions of the femoropatellar joint capsule from both stifles of 12 mature New Zealand White rabbits were used. Specimens were divided into three treatment groups (5 watts, 10 watts, and 15 watt) and one control group using a randomized block design. Specimens were placed in a 37 degrees bath of lactated Ringer's solution and laser energy was applied using a holmium:yttrium-aluminum-garnet laser in four transverse passes across the tissue at a velocity of 2 mm/sec with the handpiece set 1.5 mm from the synovial surface. Histologic analysis revealed thermal alteration of collagen (fusion) and fibroblasts (pyknosis) at all energy densities, with higher laser energy causing significantly greater morphologic changes over a larger area (P < 0.05). Application of laser energy did not significantly alter the biochemical parameters evaluated, including type I collagen content and nonreducible crosslinks (P > 0.05). This study demonstrated that nonablative laser energy caused significant thermal damage to the joint capsular tissue in an energy-dependent fashion, but type I collagen content and nonreducible crosslinks (P > 0.05). This study demonstrated that nonablative laser energy caused significant thermal damage to the joint capsular tissue in an energy-dependent fashion, but type I Collagen content and nonreducible corsslinks were not significantly altered.

Participation of lymphocyte subpopulations in the pathogenesis of experimental murine cerebral malaria

We determined the requirement for selected lymphocyte subsets and cytokines in the pathogenesis of experimental murine cerebral malaria (CM) by using gene-targeted knockout and mAb-suppressed mice. Plasmodium berghei ANKA infection induced CM in A 0/0 mice, which lack expression of surface MHC class II glycoproteins and consequently express a severe and chronic reduction in numbers of CD4+ T cells. However, when A 0/0 mice, which are on a C57BL/6 x 129 genetic background, or immune-intact C57BL/6 controls treated with anti-CD4 mAb were infected, none developed CM. The latter finding confirms an earlier report that CD4+ T cells are required for CM to occur and additionally indicates that the reduced numbers of CD4+ T cells present in A 0/0 mice are sufficient for CM development. Neither the recently described CD4+, NK1.1+ T cell subset shown to be present in A 0/0 mice nor traditional NK cells seem to be required for the induction of CM because A 0/0 and C57BL/6 mice severely depleted of both NK1.1+ populations with mAb developed CM as readily as did normal Ig-treated controls. Deficiency of Th1-associated cytokines (IFN-gamma or IL-2) in mice by gene-targeted disruptions completely inhibited CM development, whereas the lack of Th2-associated cytokines (IL-4 or IL-10) did not prevent this disease. Our observation that B cell-deficient JHD and microMT mice developed CM provides evidence that neither B cells, their products, nor B cell Ag presentation are a requisite for CM pathology. We further observed that neither beta 2m 0/0 knockout mice, which lack CD8+ alpha beta T cells, nor C57BL/6 mice depleted of CD8+ T cells with anti-CD8 mAb treatment developed CM, leading us to conclude that CD8+ T cells are also crucial for the development of CM.

Participation of lymphocyte subpopulations in the pathogenesis of experimental murine cerebral malaria

We determined the requirement for selected lymphocyte subsets and cytokines in the pathogenesis of experimental murine cerebral malaria (CM) by using gene-targeted knockout and mAb-suppressed mice. Plasmodium berghei ANKA infection induced CM in A 0/0 mice, which lack expression of surface MHC class II glycoproteins and consequently express a severe and chronic reduction in numbers of CD4+ T cells. However, when A 0/0 mice, which are on a C57BL/6 x 129 genetic background, or immune-intact C57BL/6 controls treated with anti-CD4 mAb were infected, none developed CM. The latter finding confirms an earlier report that CD4+ T cells are required for CM to occur and additionally indicates that the reduced numbers of CD4+ T cells present in A 0/0 mice are sufficient for CM development. Neither the recently described CD4+, NK1.1+ T cell subset shown to be present in A 0/0 mice nor traditional NK cells seem to be required for the induction of CM because A 0/0 and C57BL/6 mice severely depleted of both NK1.1+ populations with mAb developed CM as readily as did normal Ig-treated controls. Deficiency of Th1-associated cytokines (IFN-gamma or IL-2) in mice by gene-targeted disruptions completely inhibited CM development, whereas the lack of Th2-associated cytokines (IL-4 or IL-10) did not prevent this disease. Our observation that B cell-deficient JHD and microMT mice developed CM provides evidence that neither B cells, their products, nor B cell Ag presentation are a requisite for CM pathology. We further observed that neither beta 2m 0/0 knockout mice, which lack CD8+ alpha beta T cells, nor C57BL/6 mice depleted of CD8+ T cells with anti-CD8 mAb treatment developed CM, leading us to conclude that CD8+ T cells are also crucial for the development of CM.

Force-plate analysis of gait before and after surgical excision of calcified lesions of the supraspinatus tendon in two dogs

Two dogs with supraspinatus calcifying tendinopathy were lame in their forelimbs and were treated by the surgical excision of the calcified lesion. The lameness in both dogs improved after surgery without additional medical treatment, as evidenced by force-plate analysis of their gait.

Laparoscopic methods for castration of equids

OBJECTIVE

To evaluate 2 laparoscopic techniques for castration of horses.

DESIGN

Prospective, randomized trial.

ANIMALS

6 sexually intact male ponies.

PROCEDURE

Ponies were anesthetized and placed in dorsal recumbency. By means of restricted randomization, 1 testis in each pony was selected to undergo in situ destruction (i.e., vascular cauterization and ligation with the testis left in situ); the other testis was pulled back into the abdomen and removed. Baseline and stimulated testosterone concentrations were determined preoperatively and postoperatively. After euthanasia, the in situ testes were examined histologically.

RESULTS

There were no surgical complications. In all ponies, postoperative baseline and stimulated testosterone concentrations were consistent with castration. The testicular parenchyma of the testes that had been left in situ underwent coagulative necrosis.

CLINICAL IMPLICATIONS

In ponies and juvenile stallions, normally descended testes can be removed laparoscopically. Nonpalpable inguinal testes can be left in situ after laparoscopically ligating and transecting the testicular artery and vein. Additional experience with these approaches is necessary before their use can be recommended in mature stallions.

Effects of potentiated chlorhexidine on bacteria and tarsocrural joints in ponies

OBJECTIVES

To evaluate the bactericidal properties of chlorhexidine diacetate (CHD) after potentiation with EDTA and Tris buffer (EDTA-Tris), and to find a potentiated CHD concentration that would achieve 90 to 100% killing for all bacteria tested.

ANIMALS

6 adult ponies.

PROCEDURES

Serial dilutions of CHD, CHD in EDTA-Tris and EDTA-Tris alone were evaluated for bactericidal activity against Staphylococcus aureus, Escherichia coli, and Streptococcus zooepidemicus. The tarsocrural joints of 6 ponies were lavaged with either 1 L phosphate-buffered saline solution (control) or 1 L of 0.0005% CHD in EDTA-Tris. Synovial fluid was collected before lavage and on days 1,4, and 8. Synovia, cartilage, and bone with cartilage were collected on day 8 when the ponies were euthanatized.

RESULTS

In vitro results indicated that 0.0005% CHD in EDTA-Tris was 90% lethal to all bacteria tested. Results of synovial fluid analysis, glycosaminoglycan analysis, and histologic examination of the synovial membrane and articular cartilage indicated that joint lavage with 0.0005% CHD in EDTA-Tris was not detrimental to the synovium or the articular cartilage of pony tarsocrural joints. Changes observed were a result of the actual lavage process, the phosphate-buffered saline solution, and hemarthrosis.

CONCLUSIONS

A concentration of 0.0005% CHD in EDTA-Tris was 90% lethal to all bacteria tested. Pony tarsocrural joint lavage with 0.0005% CHD in EDTA-Tris was not detrimental to the synovium or the articular cartilage. The efficacy of 0.0005% CHD potentiated with EDTA-Tris as a potential joint lavage fluid for treatment of infectious arthritis needs to be evaluated in clinical patients.

Zygomatic osteoma with atypical heterogeneity in a dog

An osteoma of the zygomatic bone in a young dog is described. It had large, centralized radiolucent regions consisting of fatty bone marrow and sparse trabeculae. A discrete, proliferative nodule within the osteoma consisted of closely-packed woven bone trabeculae and pleomorphic osteoblasts associated with haphazard osteoid deposits, resembling osteosarcoma-like change. These heterogeneous structural features were at variance with more classic reports of osteoma, which usually describe a uniform cancellous or cortical bone architecture.

Mycobacterial keratitis in a parrot

Histologic examination revealed acid-fast organisms in a granulomatous lesion involving the cornea of an eye of a Maximilian's Parrot. Disseminated mycobacteriosis was also diagnosed. Antemortem attempts at determining the cause of the corneal lesion had been unsuccessful. Ocular involvement in birds with avian tuberculosis is uncommon. The corneal lesion in the parrot was likely initiated by a dysfunctional third eyelid.

Effects of 0.05% chlorhexidine lavage on the tarsocrural joints of horses

In six horses, a 0.05% solution of chlorhexidine diacetate was used to lavage one tarsocrural joint; the contralateral control joint was lavaged with lactated Ringer's solution. Horses were evaluated daily for lameness. Synovial fluid samples were collected on days 1, 4, and 8 for determination of protein concentration, total and differential leukocyte counts, and mucin clot formation. After death on day 8, synovium and osteochondral samples were collected from the tarsocrural joints for examination of morphology and proteoglycan staining. Lavage with chlorhexidine solution caused lameness that was reduced but still evident at day 8. Synovial protein concentration was significantly increased by chlorhexidine lavage; the greatest increase occurred on day 1. Joint lavage increased synovial leukocyte counts on day 1, primarily by increasing polymorphonuclear (PMN) cell counts. Although total synovial leukocyte counts returned to normal by day 4, PMN cell counts remained elevated through day 8; PMN cell counts for chlorhexidine-lavaged joints were typically twice that of control joints. Chlorhexidine lavage caused synovial ulceration, inflammation, and abundant fibrin accumulation. Consistent differences in proteoglycan staining were not detected between control and chlorhexidine-lavaged joints. Joint lavage with 0.05% chlorhexidine diacetate, the lowest known bactericidal concentration, is not recommended for equine joints.

Methimazole protection of rats against gentamicin-induced nephrotoxicity

Methimazole was previously shown to protect rats, mice, and (or) dogs against cisplatin-, cephaloridine-, 2-bromohydro-quinone-, and S-(1,2-dichlorovinyl)-L-cysteine-induced nephrotoxicity. In this study, methimazole effects on gentamicin (GM) induced nephrotoxicity were examined. Rats given GM (40 mg/kg) twice daily for 10 days exhibited higher blood urea nitrogen (BUN) concentrations and severe necrosis of virtually all proximal tubules compared with saline-treated controls. Rats cotreated with methimazole (20 mg/kg) exhibited minimal proximal tubular necrosis and were protected against GM-induced increase in BUN concentrations, despite having higher kidney GM concentrations. Rats given GM alone for 3 days exhibited no proximal tubular necrosis and no elevation of BUN values. However, these rats exhibited an increase in nonprotein disulfide concentrations and a decrease in renal protein thiol and protein disulfide concentrations, as opposed to rats given GM and methimazole. Together the results show that methimazole was an effective antagonist of GM-induced nephrotoxicity. Methimazole did not inhibit GM renal uptake but may protect against GM-induced nephrotoxicity by acting as an antioxidant within the kidneys.

Roles of cysteine conjugate beta-lyase and S-oxidase in nephrotoxicity: studies with S-(1,2-dichlorovinyl)-L-cysteine and S-(1,2-dichlorovinyl)-L-cysteine sulfoxide

Effects of S-(1,2-dichlorovinyl)-L-cysteine (DCVC) and its putative metabolite DCVC sulfoxide (DCVCO) on renal function in vivo and in vitro were investigated to assess the role of sulfoxidation in the mechanism of toxicity of cysteine S-conjugates. Both conjugates were potent nephrotoxicants in rats in vivo, but at equimolar doses, DCVCO produced greater renal injury (i.e., increases in blood urea nitrogen levels and anuria and more severe and widespread proximal tubular necrosis) than DCVC. Pretreatment of rats with aminooxyacetic acid (AOAA), a selective cysteine conjugate beta-lyase (beta-lyase) inhibitor, did not protect against DCVCO nephrotoxicity, whereas rats given DCVC and AOAA exhibited partial protection. These results suggest that in addition to cleavage by the beta-lyase, sulfoxidation by the cysteine conjugate S-oxidase (S-oxidase) may play a role in DCVC nephrotoxicity. In isolated rat kidney proximal tubular (PT) and distal tubular (DT) cells, both DCVC and DCVCO produced time- and concentration-dependent increases in the release of lactate dehydrogenase. Because DCVC was generally more toxic in PT cells and DCVCO was more toxic in DT cells, an attempt was made to correlate in vitro cytotoxicity with the cellular distribution of the beta-lyase and S-oxidase. The finding that beta-lyase activity exhibited a 2-fold higher Vmax/Km ratio in PT cells than in DT cells, the greater inhibition of both beta-lyase activity and DCVC toxicity by AOAA in PT cells than in DT cells and the lower (40%) S-oxidase activity in PT cells than in DT cells provide evidence for the importance of the beta-lyase in DCVC toxicity in PT cells. The finding that DCVCO was more toxic in DT cells than in PT cells and the inability of AOAA to protect DT cells from DCVC-induced cytotoxicity, however, provide further evidence for DCVC bioactivation by S-oxidase.(ABSTRACT TRUNCATED AT 250 WORDS)

An influenza A (H1N1) virus, closely related to swine influenza virus, responsible for a fatal case of human influenza

In July 1991, an influenza A virus, designated A/Maryland/12/91 (A/MD), was isolated from the bronchial secretions of a 27-year-old animal caretaker. He had been admitted to the hospital with bilateral pneumonia and died of acute respiratory distress syndrome 13 days later. Antigenic analyses with postinfection ferret antisera and monoclonal antibodies to recent H1 swine hemagglutinins indicated that the hemagglutinin of this virus was antigenically related to, but distinguishable from, those of other influenza A (H1N1) viruses currently circulating in swine. Oligonucleotide mapping of total viral RNAs revealed differences between A/MD and other contemporary swine viruses. However, partial sequencing of each RNA segment of A/MD demonstrated that all segments were related to those of currently circulating swine viruses. Sequence analysis of the entire hemagglutinin, nucleoprotein, and matrix genes of A/MD revealed a high level of identity with other contemporary swine viruses. Our studies on A/MD emphasize that H1N1 viruses in pigs obviously continue to cross species barriers and infect humans.

Antigenic and genetic analysis of a recently isolated H1N1 swine influenza virus

Hemagglutinins (HA) of H1N1 swine influenza viruses isolated in the United States have remained antigenically and genetically conserved for many years. In contrast to such conservation, the HA of A/Swine/Nebraska/1/92 (Sw/Neb) could readily be distinguished from those of contemporary porcine viruses. Twenty-eight amino acid mutations differentiated the HA of Sw/Neb and A/Swine/Indiana/1726/88, the most recent H1N1 swine influenza virus for which HA sequence data were available. Among these differences were mutations at potential asparagine-linked glycosylation sites and charge changes at many residues. The Sw/Neb virus also could be differentiated from other swine influenza viruses in hemagglutination-inhibition assays with monoclonal antibodies to recent H1 swine HA. Nonetheless, overall sequence analysis of the HA and the nucleoprotein genes of Sw/Neb indicated that this virus was more closely related genetically to classic H1N1 swine influenza viruses than to H1N1 avian or human viruses. Infection of swine with Sw/Neb under experimental conditions induced clinical signs and lesions typical of swine influenza. However, affected swine in the field had high, persistent fevers, but relatively mild signs of respiratory tract disease. This study indicated that an antigenically and genetically novel variant of swine influenza virus was detected in the United States.

Fumonisin toxicosis in swine: clinical and pathologic findings

From a series of experimental studies with pigs (12-16 kg), either pulmonary edema or liver failure emerged as a distinct pathogenetic expression of fumonisin B1 (FB1) toxicosis. The primary determinant as to which pathogenetic consequence developed was the quantity (dose) of the mycotoxin fed or intubated per kilogram of body weight per day. Pigs intubated with a minimum of 16 mg FB1/kg/day developed severe interlobular edema with or without hydrothorax and variably severe pulmonary edema. Pigs intubated with < 16 mg FB1/kg/day or pigs fed diets containing 200 mg FB1/kg of feed developed marked icterus and hepatocellular necrosis. The spectrum of degrees of severity of pulmonary edema observed in the experimental pigs allowed rational speculation regarding evolution of the pathologic changes.

Isolation of feline eosinophils via peritoneal lavage

Fourteen cats were inoculated orally with 1 of 2 infective doses of Toxocara canis to induce eosinophilia. Cats were subsequently challenge exposed twice via intraperitoneal injection with 1 of 2 T canis antigen preparations. Peritoneal lavage was performed 2 days after antigenic challenge exposure, and eosinophils in the peritoneal lavage fluid were quantified. None of the cats developed clinical signs of disease after infection. All cats developed peripheral eosinophilia after infection. Significant (P < 0.05) difference in mean eosinophil count from the lavage fluid was observed between lavage 1 (prechallenge exposure) and lavages 2 and 3 (postchallenge exposure) in both groups of cats. Significant difference in eosinophil count was not found between cats given different doses of eggs. After initial challenge exposure, significantly (P < 0.05) more eosinophils were obtained from cats given antigen preparation 2 (prep-2) than from those given antigen prep-1. This difference was no longer observed after the second challenge exposure with higher doses of either antigen prep-1 or prep-2. In cats given antigen prep-2, significant difference was not found between lavages 2 and 3. However, in cats given antigen prep-1, eosinophil count was significantly (P = 0.005) greater in fluid obtained from lavage 3, compared with eosinophil count from lavage 2. Mean +/- SEM percentage of eosinophils in the fluid from lavage 3 in all cats was 70.8 +/- 2.2%. Other cell types included macrophages, neutrophils, lymphocytes, and mast cells. Gross postmortem findings were mild. One- to 3-mm nodular white foci of inflammation were observed on the serosal surfaces of the liver, spleen, kidneys, and omentum.(ABSTRACT TRUNCATED AT 250 WORDS)

Methimazole as a protectant against cisplatin-induced nephrotoxicity using the dog as a model

The protective effect of methimazole, a commonly used antithyroid drug, on cisplatin-induced nephrotoxicity was studied. Eight dogs received 80 mg/m2 cisplatin i.v. without saline prehydration. Dogs were randomized into two groups of four dogs each: one group received 40 mg/kg methimazole i.p. at 30 min prior to and 4 h after cisplatin delivery, and the other group received saline placebo i.p. Methimazole protected dogs against the in vivo nephrotoxicity elicited by cisplatin as evidenced by clinicopathologic and histopathologic indices. Protection was not complete, as methimazole-treated animals developed mild histopathologic renal changes. Measures of renal oxidative stress did not differ between the two groups at day 5 following cisplatin treatment. No difference was noted for serum thyroxine concentrations before or after therapy in either group; however, serum levels of 3,5,3'-triiodothyronine were significantly higher on day 5 in both groups of dogs receiving cisplatin, regardless of whether they received methimazole or not. Methimazole as used in this study was found to be well tolerated in dogs over the short term, with no significant clinical or clinicopathologic toxicity being observed. The results of this study support the additional evaluation of methimazole as a protectant against cisplatin-induced nephrotoxicity using the dog as a model.

Effects of a thromboxane synthetase inhibitor on established immune complex glomerulonephritis in dogs

Twelve Beagles were inoculated with concanavalin A, and after a mean ninefold increase in antibody titer, 1 mg of concanavalin A was infused into each renal artery of each dog to induce in situ immune complex glomerulonephritis. Starting 4 weeks after renal arterial infusion, 6 dogs were treated orally 3 times daily with 30 mg of 3-methyl-2 (3 pyridyl)-1-indolectanoic acid (CGS 12970)/kg of body weight, a thromboxane synthetase inhibitor, and 6 dogs (control group) received a gelatin capsule 3 times daily. Endogenous creatinine clearance and 24-hour urinary excretion of protein and thromboxane B2 were determined for each dog prior to renal arterial infusion, at the initiation of treatment and at 2, 4, 6, and 8 weeks after initiation of treatment. In addition, methyoxy-3H inulin clearance was determined at initiation of treatment and 4 and 8 weeks later. Renal specimens were examined histologically at the initiation of treatment and 4 and 8 weeks later. Glomerular mononuclear profiles/microns 3 were determined from at least 10 equatorially sectioned glomeruli from each dog. Paired t tests were used to compare mean values at the various time points to the respective mean baseline value and 2-sample t tests were used to evaluate differences between treatment groups. At the start of treatment (4 weeks after renal arterial infusion of concanavalin A), histologic evaluation of renal specimens revealed glomerular epithelial crescent formation, mononuclear cell proliferation, and infiltration of neutrophils. Mononuclear cell profiles and urinary excretion of protein and thromboxane B2 were significantly increased, but endogenous creatinine clearance values were unchanged.(ABSTRACT TRUNCATED AT 250 WORDS)

Methimazole protection of rats against chemically induced kidney damage in vivo

Because methimazole has antioxidant properties, the effects of methimazole treatment on cephaloridine, S-(1,2-dichlorovinyl)-L-cysteine (DCVC), 2-bromohydroquinone (2-BHQ) and cis-diaminedichloroplatinum (II) (cisplatin)-induced nephrotoxicity were investigated. Rats given cephaloridine (1 g/kg), cisplatin (5 mg/kg), DCVC (100 mg/kg) or 2-BHQ (157 mg/kg) i.p. exhibited significant elevations in blood urea nitrogen concentrations, which correlated with appearance of distinct renal histopathological changes. Cephaloridine, DCVC or 2-BHQ-induced nephrotoxicity was reduced only when methimazole (20-40 mg/kg) was given 30 min before the nephrotoxicant, whereas cisplatin-induced nephrotoxicity was reduced when methimazole was given 30 min before and up to 4 hr after cisplatin. Because the renal organic acid transport system plays an important role in the nephrotoxicity of cephaloridine, cisplatin and DCVC, the role of the organic acid transport system in the renal uptake of methimazole was investigated. With rat kidney cortical slices, methimazole uptake was time- and concentration-dependent; however, the organic acid transport substrates, probenecid (1 mM) and p-aminohippuric acid (7.5 mM), were ineffective in blocking methimazole uptake. Furthermore, cephaloridine (1 mM) uptake by kidney cortical slices was not affected by methimazole (5 mM). Rats given methimazole (40 mg/kg) 30 min before cephaloridine (2 g/kg) had serum and kidney cephaloridine concentrations similar to rats given cephaloridine only, but the methimazole-pretreated rats were significantly protected against cephaloridine-induced oxidation of renal nonprotein thiols. These results show that methimazole does not inhibit the transport of cephaloridine into the kidneys, but may protect against cephaloridine-induced renal damage by acting as an antioxidant within the kidneys.

Effects of thromboxane synthetase inhibition on immune complex glomerulonephritis

To determine the role of thromboxane A2 in the pathogenesis of experimentally induced immune complex glomerulonephritis, 12 concanavalin A-immunized Beagles were infused with 1 mg of concanavalin A via each renal artery and treated twice daily for 8 days with either 30 mg of CGS 12970/kg, PO, a specific thromboxane synthetase inhibitor, or placebo. The effect of treatment was assessed by measuring endogenous creatinine clearance and urine protein and eicosanoid excretion, and by evaluating changes in glomerular morphometric characteristics. On postinfusion day 8, urine protein, thromboxane B2, and 11-dehydro-thromboxane B2 excretion, glomerular epithelial crescent formation, and glomerular cell proliferation in the CGS 12970-treated dogs were significantly decreased when compared with values in the placebo-treated group. Differences were not observed in endogenous creatinine clearance, urine prostaglandin E2 and 6-keto-prostaglandin F1 alpha excretion, or glomerular polymorphonuclear leukocyte infiltration between groups in this study. These findings suggest thromboxane A2 has a role in the development of immune complex glomerulonephritis and that thromboxane synthetase inhibition may be beneficial in attenuating some of the functional and histological changes associated with immune complex glomerulonephritis.