Differences in expression of uroplakin III, cytokeratin 7, and cyclooxygenase-2 in canine proliferative urothelial lesions of the urinary bladder.

The expression of immunohistochemical markers that have been used in diagnosis and/or prognostication of urothelial tumors in humans (uroplakin III [UPIII], cytokeratin 7 [CK7], cyclooxygenase-2 [COX-2], and activated caspase 3) was evaluated in a series of 99 canine proliferative urothelial lesions of the urinary bladder and compared to the lesion classification and grade as defined by the World Health Organization / International Society of Urologic Pathology consensus system. There were significant associations between tumor classification and overall UPIII pattern (P = 1.49 × 10(-18)), loss of UPIII (P = 1.27 × 10(-4)), overall CK7 pattern (P = 4.34 × 10(-18)), and COX-2 pattern (P = 8.12 × 10(-25)). In addition, there were significant associations between depth of neoplastic cell infiltration into the urinary bladder wall and overall UPIII pattern (P = 1.54 × 10(-14)), loss of UPIII (P = 2.07 × 10(-4)), overall CK7 pattern (P = 1.17 × 10(-13)), loss of CK7 expression (P = .0485), and COX-2 pattern (P = 8.23 × 10(-21)). There were no significant associations between tumor classification or infiltration and caspase 3 expression pattern.

Wildlife reservoirs of bovine tuberculosis worldwide: hosts, pathology, surveillance, and control.

Bovine tuberculosis due to Mycobacterium bovis is a zoonotic disease classically carried by cattle and spilling over into humans primarily by the ingestion of milk. However, in recent decades, there have been many endemic geographic localities where M. bovis has been detected infecting wildlife reservoirs, limiting the progress toward eradication of this disease from cattle. These include cervids in North America, badgers in Great Britain, feral pigs in Europe, brushtailed possums in New Zealand, and buffalo in South Africa. An overview of these wildlife hosts will provide insight into how these reservoirs maintain and spread the disease. In addition, the authors summarize the pathology, current ongoing methods for surveillance, and control. In many instances, it has proven to be more difficult to control or eradicate bovine tuberculosis in wild free-ranging species than in domesticated cattle. Furthermore, human influences have often contributed to the introduction and/or maintenance of the disease in wildlife species. Finally, some emerging themes regarding bovine tuberculosis establishment in wildlife hosts, as well as conclusions regarding management practices to assist in bovine tuberculosis control and eradication in wildlife, are offered.

Distribution of eastern equine encephalomyelitis viral protein and nucleic acid within central nervous tissue lesions in white-tailed deer (Odocoileus virginianus).

An outbreak of eastern equine encephalomyelitis (EEE) occurred in Michigan free-ranging white-tailed deer (Odocoileus virginianus) during late summer and fall of 2005. Brain tissue from 7 deer with EEE, as confirmed by reverse transcriptase polymerase chain reaction, was studied. Detailed microscopic examination, indirect immunohistochemistry (IHC), and in situ hybridization (ISH) were used to characterize the lesions and distribution of the EEE virus within the brain. The main lesion in all 7 deer was a polioencephalomyelitis with leptomeningitis, which was more prominent within the cerebral cortex, thalamus, hypothalamus, and brainstem. In 3 deer, multifocal microhemorrhages surrounded smaller vessels with or without perivascular cuffing, although vasculitis was not observed. Neuronal necrosis, associated with perineuronal satellitosis and neutrophilic neuronophagia, was most prominent in the thalamus and the brainstem. Positive IHC labeling was mainly observed in the perikaryon, axons, and dendrites of necrotic and intact neurons and, to a much lesser degree, in glial cells, a few neutrophils in the thalamus and the brainstem, and occasionally the cerebral cortex of the 7 deer. There was minimal IHC-based labeling in the cerebellum and hippocampus. ISH labeling was exclusively observed in the cytoplasm of neurons, with a distribution similar to IHC-positive neurons. Neurons positive by IHC and ISH were most prominent in the thalamus and brainstem. The neuropathology of EEE in deer is compared with other species. Based on our findings, EEE has to be considered a differential diagnosis for neurologic disease and meningoencephalitis in white-tailed deer.

Proposal of a 2-tier histologic grading system for canine cutaneous mast cell tumors to more accurately predict biological behavior.

Currently, prognostic and therapeutic determinations for canine cutaneous mast cell tumors (MCTs) are primarily based on histologic grade. However, the use of different grading systems by veterinary pathologists and institutional modifications make the prognostic value of histologic grading highly questionable. To evaluate the consistency of microscopic grading among veterinary pathologists and the prognostic significance of the Patnaik grading system, 95 cutaneous MCTs from 95 dogs were graded in a blinded study by 28 veterinary pathologists from 16 institutions. Concordance among veterinary pathologists was 75% for the diagnosis of grade 3 MCTs and less than 64% for the diagnosis of grade 1 and 2 MCTs. To improve concordance among pathologists and to provide better prognostic significance, a 2-tier histologic grading system was devised. The diagnosis of high-grade MCTs is based on the presence of any one of the following criteria: at least 7 mitotic figures in 10 high-power fields (hpf); at least 3 multinucleated (3 or more nuclei) cells in 10 hpf; at least 3 bizarre nuclei in 10 hpf; karyomegaly (ie, nuclear diameters of at least 10% of neoplastic cells vary by at least two-fold). Fields with the highest mitotic activity or with the highest degree of anisokaryosis were selected to assess the different parameters. According to the novel grading system, high-grade MCTs were significantly associated with shorter time to metastasis or new tumor development, and with shorter survival time. The median survival time was less than 4 months for high-grade MCTs but more than 2 years for low-grade MCTs.

Malignant lymphoma in african lions (panthera leo).

Malignant lymphoma has become an increasingly recognized problem in African lions (Panthera leo). Eleven African lions (9 male and 2 female) with clinical signs and gross and microscopic lesions of malignant lymphoma were evaluated in this study. All animals were older adults, ranging in age from 14 to 19 years. Immunohistochemically, 10 of the 11 lions had T-cell lymphomas (CD3(+), CD79a(-)), and 1 lion was diagnosed with a B-cell lymphoma (CD3(-), CD79a(+)). The spleen appeared to be the primary site of neoplastic growth in all T-cell lymphomas, with involvement of the liver (6/11) and regional lymph nodes (5/11) also commonly observed. The B-cell lymphoma affected the peripheral lymph nodes, liver, and spleen. According to the current veterinary and human World Health Organization classification of hematopoietic neoplasms, T-cell lymphoma subtypes included peripheral T-cell lymphoma (4/11), precursor (acute) T-cell lymphoblastic lymphoma/leukemia (2/11), chronic T-cell lymphocytic lymphoma/leukemia (3/11), and T-zone lymphoma (1/11). The single B-cell lymphoma subtype was consistent with diffuse large B-cell lymphoma. Feline leukemia virus (FeLV) and feline immunodeficiency virus (FIV) testing by immunohistochemistry on sections of malignant lymphoma was negative for all 11 lions. One lion was seropositive for FeLV. In contrast to domestic and exotic cats, in which B-cell lymphomas are more common than T-cell lymphomas, African lions in this study had malignant lymphomas that were primarily of T-cell origin. Neither FeLV nor FIV, important causes of malignant lymphoma in domestic cats, seems to be significant in the pathogenesis of malignant lymphoma in African lions.

Congenital ureteral ectopia in continent and incontinent-related Entlebucher mountain dogs: 13 cases (2006-2009).

BACKGROUND: Ectopic ureters (EUs) associated with varying combinations of urinary incontinence, hydronephrosis, and urinary tract infection have been identified in related North American Entlebucher Mountain Dogs. OBJECTIVES: To characterize the disease phenotype in affected dogs and evaluate possible modes of inheritance. ANIMALS: Twenty client-owned Entlebucher Mountain Dogs. Nine dogs had clinical signs of urinary tract disease. METHODS: Prospective case series in which 17 dogs were evaluated with excretory urography, ultrasonography, and urethrocystoscopy. Three additional dogs were evaluated by necropsy alone. Clinical and pedigree histories from 165 North American Entlebuchers were compiled for analysis. RESULTS: Eleven female and 2 male dogs were found to have EUs. Six females and 1 male were continent. Bilateral intravesicular ectopic ureters (IVEUs) were identified in 9 dogs, bilateral extravesicular ectopic ureters (EVEUs) in 3 dogs, and 1 dog had IVEU and EVEU. Hydronephrosis was identified in 5 dogs, 3 of which had bilateral IVEUs. Two necropsied dogs had bilateral hydronephrosis with presumed ureterovesical junction obstruction associated with chronic granulation tissue or lymphoplasmacytic inflammation. Twenty-six dogs with EUs were identified in the pedigree. Because of incomplete penetrance, mode of inheritance could not be determined. CONCLUSIONS AND CLINICAL IMPORTANCE: Ureteral ectopia is common in North American Entlebucher Mountain Dogs and clinical signs alone could not reliably predict disease phenotype. EVEUs were associated with urinary incontinence and occasionally hydronephrosis. IVEUs were clinically silent or associated with hydronephrosis. Further analyses are necessary to confirm and characterize the hereditary nature of the disorder.

Embryo toxicity of 2,3,7,8-tetrachlorodibenzo-p-dioxin to the wood duck (Aix sponsa).

We examined the sensitivity of the wood duck (Aix sponsa) embryo to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) by injecting the toxicant into their eggs. Six groups of wood duck eggs (n = 35 to 211 per trial) were injected with 0 to 4600 pg TCDD/g egg between 2003 and 2005. Injections were made into yolk prior to incubation, and eggs were subsequently incubated and assessed weekly for mortality. Significant TCDD-induced mortality was not observed through day 25 (90% of incubation). Liver, heart, eye, and brain histology were generally unremarkable. Hepatic ethoxyresorufin-O-deethylase activity, a biomarker of dioxin-like compound exposure, was induced by 12-fold in the 4600 pg/g treatment relative to controls. The median lethal dose for chicken (Gallus domesticus) eggs we dosed identically to wood duck eggs was about 100 pg/g, similar to other assessments of chickens. Among dioxin-like compound embryo lethality data for 15 avian genera, the wood duck 4600 pg/g no-observed-effect level ranks near the middle. Because no higher doses were tested, wood ducks may be like other waterfowl (order Anseriformes), which are comparatively tolerant to embryo mortality from polychlorinated dibenzo-p-dioxins and dibenzofurans when exposed by egg injection.

Marek's disease virus-induced skin leukosis in scaleless chickens: tumor development in the absence of feather follicles.

Marek's disease virus (MDV) is an oncogenic cell-associated herpesvirus that causes T-cell lymphoma in chickens. Lymphoproliferative neoplasms in Marek's disease (MD) occur in various organs and tissues, including the viscera, peripheral nerves, skin, gonads, and musculatures. MDV is restrictively produced in the feather follicle epithelial (FFE) cells, and it gains access to the external environment via infected cells or as infectious enveloped cell-free virus particles. The goals of the present study were to 1) determine whether the MDV-induced skin lesions are neoplastic in nature or inflammatory reactions to viral infection, 2) determine whether physical presence of feather follicles (FF) is necessary for skin tumor development, and 3) study the role of skin epithelial cells not associated with feathers or FF in the replication and dissemination of infectious virus particles. Scaleless chickens that produce only a few scattered feathers and no sculate scales along the anterior metatarsi were used as a unique model to study the pathogenesis of dermal lesions. Histologic and immunohistochemical analysis revealed that the cutaneous lesions were tumorous as was manifested by massive accumulation of lymphoblasts and extensive activation of meq oncoprotein, the hallmark of MDV oncogenesis, within the skin lesions. Neoplastic cutaneous lesions in the scaleless chickens indicate that feather follicles are not necessary for skin tumor development. Finally, our preliminary data indicate that inoculation with supernatant fluid from homogenized and sonicated skin samples of MDV-infected scaleless chickens induces MD in susceptible birds, suggesting that skin epithelial cells not associated with FF also harbor infectious viral particles.

Experimental inoculation of wild turkeys (Meleagris gallopavo) with Mycobacterium bovis.

Although avian species are known to be susceptible to infection with Mycobacterium spp. organisms, much remains unknown about the susceptibility of birds to infection with M. bovis. The objective of this current study was to determine if wild turkeys (Meleagris gallopavo) can be infected with M. bovis when inoculated by the oral or intratracheal route. Six turkeys were orally inoculated and another six were inoculated via the trachea with a high dose of M. bovis, 1 x 10(5) CFU/ml. Six turkeys were sham-inoculated controls. Two turkeys from each treatment group were sacrificed on days 30, 60, and 90 postinoculation. There were no gross or microscopic lesions consistent with mycobacteriosis in the 23 inoculated turkeys over the 90-day duration of this study. Fecal cultures were also consistently negative for M. bovis when sampled before inoculation and on days 1, 30, and 60 postinoculation. Two intratracheally inoculated turkeys were positive for M. bovis in visceral tissues at 30 days postinoculation. However, this finding was only indicative of passive persistence of mycobacteria in the tissues and not of infection, as there were no attendant lesions or clinical compromise to support infection. Thus, it can be concluded that young wild turkeys are resistant to infection with M. bovis and, therefore, pose minimal threat as reservoir or spillover hosts for this organism.

Classification of canine urinary bladder urothelial tumours based on the World Health Organization/International Society of Urological Pathology consensus classification.

One hundred canine urinary bladder urothelial (transitional cell) tumours, including roughly equal numbers of benign and malignant forms, were retrospectively categorized in accordance with the newly described human consensus classification of the World Health Organization/International Society of Urological Pathology (WHO/ISUP). The tumours were reviewed and classified by three veterinary pathologists from Michigan State University and two human pathologists from the Armed Forces Institute of Pathology (AFIP). The current human WHO/ISUP classification system was considered to be readily applicable to the dog. Canine tumours, however, differed from human tumours in that the great majority showed extensive glandular differentiation (or metaplasia) and hyperplastic lesions tended to be more florid than those seen in human beings. The various diagnoses and grades assigned to the tumours were highly consistent between all reviewing pathologists. This paper presents the salient features of the new WHO and ISUP consensus classification and provides illustrations of the various tumour types that were directly applicable to the dog.

Inhibition of estrogen receptor action by a naturally occurring variant in human breast tumors.

It is fairly well accepted that the presence of estrogen receptor (ER) and progesterone receptor (PgR) identifies breast cancer patients with a lower risk of relapse and better overall survival. But patients with discordant receptors, the ER+/PgR- phenotype, are often intermediate in clinical response. We focused upon this group of patients and have identified a truncated ER which is abundant in some ER+/PgR- breast tumors and which inhibits the binding of wild-type ER to its cognate response element. This variant interferes in a dominant negative manner with wild-type ER function and may represent a mechanism for modulation of estrogen responsiveness.

Variant human breast tumor estrogen receptor with constitutive transcriptional activity.

Since progesterone receptor (PgR) is normally induced by estrogen, breast cancer lacking estrogen receptor (ER) would also be expected to lack PgR. However, a small percentage of breast cancers are ER- yet PgR+. These tumors might possess an ER which is defective in estrogen binding but is still functional in stimulating estrogen-responsive genes such as PgR. We have now detected such a variant, lacking exon 5 of the hormone-binding domain, using complementary DNA amplified by the polymerase chain reaction. This variant was the predominate ER RNA expressed in three ER-/PgR+ tumors. Furthermore, the variant ER constitutively activates transcription of a normally estrogen-dependent gene construct in yeast cells. The variant ER could explain the expression of PgR in certain tumors and have therapeutic implications.

Resistance of Mallard ducks (Anas platyrhynchos) to experimental inoculation with Mycobacterium bovis.

The purpose of this study was to investigate whether mallard ducks (Anas platyrhynchos) are susceptible to infection with Mycobacterium bovis by either oral or intratracheal inoculation and to assess their potential role in the spread of bovine tuberculosis. Six ducks were orally inoculated with 1.0 x 10(5) colony-forming units of M. bovis, six ducks were intratracheally inoculated with the same dose, and six ducks served as sham-inoculated controls. The study length was 90 days postinoculation, with samples of two birds from each group necropsied at 30-day intervals. Both fecal and tissue samples were collected for mycobacterial culture. None of the inoculated ducks shed M. bovis in their feces at any culture point (days 1, 30, and 60) during the study. No evidence of illness or weight loss was present during the course of the study, and only one duck had M. bovis isolated from any tissue, although there were no associated microscopic lesions. Mallard ducks were highly resistant to infection with M. bovis following high-dose inoculation and did not shed the organism in their feces. This study was conducted using high-dose inoculation; therefore, it appears that ducks are unlikely to play any significant role in the transmission of M. bovis between infected and uninfected mammalian hosts.

A simple polymerase chain reaction method for detection and cloning of low-abundance transcripts.

A simplified polymerase chain reaction (PCR) technique for the detection, semiquantitation and cloning of low-abundance RNAs is described. This assay involves first-strand cDNA synthesis by reverse transcription of mRNA with specific oligonucleotide primers, followed by second-strand synthesis and PCR amplification, in the same tube with only the addition of TaqI DNA polymerase. The assay is sufficiently sensitive to detect target RNA from as little as 1 ng of total RNA. The beta-actin transcripts may also be simultaneously reverse transcribed, amplified and used as an internal standard to determine relative expression of specific RNAs. Using this simple technique, expression of the multidrug resistance (mdr 1) gene can easily be detected in human breast tumors. The technique is also applicable for the cloning of rare transcripts.

Analysis of the hemodynamic and ventilatory effects of laparoscopic cholecystectomy.

Laparoscopic cholecystectomy uses carbon dioxide, a highly diffusable gas, for insufflation. With extended periods of insufflation, patient arterial carbon dioxide levels may be adversely altered. Patients were selected for laparoscopic cholecystectomy using the same criteria as for open cholecystectomy. Twenty patients (group 1) had normal preoperative cardiopulmonary status (American Society of Anesthesiologists class I), while 10 patients (group 2) had previously diagnosed cardiac or pulmonary disease (class II or III). Demographic, hemodynamic, arterial blood gas, and ventilatory data were collected before peritoneal insufflation and at intervals during surgery. Patients with preoperative cardiopulmonary disease demonstrated significant increases in arterial carbon dioxide levels and decreases in pH during carbon dioxide insufflation compared with patients without underlying disease. Results of concurrent noninvasive methods of assessing changes in partial arterial pressures of carbon dioxide (end-tidal carbon dioxide measured with mass spectrographic techniques) may be misleading and misinterpreted because changes in partial arterial pressures of carbon dioxide are typically much smaller than changes in arterial blood levels and, unlike arterial gas measurements, do not indicate the true level of arterial hypercarbia. During laparoscopic cholecystectomy, patients with chronic cardiopulmonary disease may require careful intraoperative arterial blood gas monitoring of absorbed carbon dioxide.

Potentiation of mercury-induced nephrotoxicity by endotoxin in the Sprague-Dawley rat.

Endotoxin (lipopolysaccharide; LPS) and mercury are nephrotoxic compounds of food safety concern. Endotoxin is a product of cell walls of gram negative bacteria. Humans are constantly exposed to LPS through food, water and air. Food is the main source of mercury exposure for humans. Endotoxin potentiates the toxicity of a number of xenobiotics, but its interaction with nephrotoxic heavy metals has not been investigated. We tested the hypothesis that endotoxin enhances mercury-induced nephrotoxicity. Thirty-two, 41-43-day-old, male Sprague-Dawley rats were allocated randomly to four groups of eight rats each as follows: group I received 0.9% sodium chloride, group II received 2.0 mg of Escherichia coli 0128:B12 LPS kg(-1) once, group III received 0.5 mg mercuric chloride kg(-1) once, and group IV received 2.0 mg E. Coli 0128:B12 LPS kg(-1) once 4 h before receiving 0.5 mg mercury chloride kg(-1) once. Mercury, LPS and 0.9% sodium chloride were all injected IV through the tail vein. Rats were monitored for 48 h after mercury injection. Serum creatinine, urea nitrogen, and polyuria were significantly increased in rats given LPS plus mercury relative to those given either agent alone or saline (P

Augmentation of mercury-induced nephrotoxicity by endotoxin in the mouse.

Endotoxin (lipopolysaccharide; LPS) and mercury are compounds of food safety concern. Endotoxin is a product of cell walls of gram negative bacteria. Humans are constantly exposed to LPS through infection plus translocation into circulation from the gastrointestinal tract. Food is the major source of mercury in humans. The toxic interaction between LPS and mercury has not been well investigated. In a previous study, we demonstrated that LPS potentiated mercury-induced nephrotoxicity in the rat. Whether this observation was species specific was not clear. In this study we tested the hypothesis that LPS enhances mercuric chloride (HgCl(2))-induced nephrotoxicity in mice. In a 2x2 factorial design, mice received either Escherichia coli 0128:B12 endotoxin (2.0 mg/kg body weight) or 200 microliter of 0.9% sodium chloride (saline), and this was followed 4 h later by either mercury (1.75 mg mercuric chloride per kg body weight) or 200 microliter of saline. Mice were monitored for 48 h. Monitored end-points included body and renal weights, urine volume, renal histology and ultrastructural pathology, serum urea nitrogen and creatinine, selected serum and urine cytokines, and renal mercury concentrations. Endotoxin by itself was not nephrotoxic at the dose used in this study. Overall, mice given LPS plus mercury were the most severely affected. Mice given LPS and mercury also had significantly greater renal mercury concentration than those given mercury alone (P

Hypercarbia during carbon dioxide pneumoperitoneum.

Patients with cardiopulmonary insufficiency undergoing laparoscopic surgery with carbon dioxide (CO2) pneumoperitoneum may retain CO2 resulting in clinically significant respiratory acidosis. A canine model of pulmonary emphysema induced by papain inhalation was utilized to evaluate the respiratory effects of both CO2 and helium pneumoperitoneum. Prior to papain inhalation and 5 and 8 weeks after initial treatment under general anesthesia, mechanical ventilation was adjusted to maintain the end-tidal CO2 (ETCO2) at 40 mm Hg during baseline and pneumoperitoneum physiologic monitoring periods. Utilizing an analysis of variance, hemodynamic and respiratory physiologic parameters were compared. In this canine model, all dogs demonstrated consistent hypercarbia during CO2 pneumoperitoneum prior to papain treatments, but CO2 retention was significantly increased in the emphysematous state. The occurrence of hypercarbia during CO2 pneumoperitoneum may be underestimated by ETCO2 monitoring as was revealed by an increased PaCO2 (arterial carbon dioxide pressure)-ETCO2 gradient with an increasing time interval between papain exposure and period of physiologic monitoring. Irrespective of the pulmonary condition of the dog, helium pneumoperitoneum did not produce any hypercarbic or acidic changes when compared with the concomitant baseline period of dogs prior to the induction of pneumoperitoneum, thus suggesting that helium pneumoperitoneum may be a reasonable alternative in patients at risk for CO2 retention.

Lockjaw syndrome in cockatiels associated with sinusitis.

Two cases where multiple juvenile cockatiels exhibited inappetance, depression, upper respiratory signs, and "lockjaw" are described. Symptoms progressed over several weeks until all birds died, in spite of antibacterial therapy. Seven affected birds from each case were submitted for diagnostic evaluation. Microscopically, all birds had necrotizing rhinitis and sinusitis, as well as myositis, perineuritis and osteomyelitis affecting the jaw muscles and cranial bones. Multiple bacterial agents were isolated from the lungs and sinuses in both cases. Juvenile cockatiels appear to be particularly susceptible to temporomandibulitis, temporomandibular joint rigidity, or "lockjaw". Once chronic inflammation and fibrosis develop, it appears unlikely that jaw mobility can be restored.

Development and application of an immunohistochemical staining technique to detect avian polyomaviral antigen in tissue sections.

An immunohistochemical staining technique was developed to detect polyomaviral antigens of budgerigar fledgling disease in formalin-fixed tissue sections. This technique used an indirect avidin-biotin, alkaline phosphatase labeling system with a mixture of monoclonal antibodies developed against the virus major capsid protein. The staining technique was applied retrospectively to 24 avian accessions which were originally diagnosed as budgerigar fledgling disease or avian polyomavirus infection based on microscopic findings including typical intranuclear inclusions. Immunohistochemical staining resulted in positive reactions in some tissues from 17 of 24 cases. The tissues most frequently containing typical intranuclear inclusions or positive immunohistochemical staining were the spleen, liver, and kidney. Neither of the 2 nonpsittacine cases was positive immunohistochemically. This technique may be used wither as a rapid test on routinely processed diagnostic samples to confirm the presence of avian polyomavirus or for pathogenesis research studies.