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Expression of P-glycoprotein, a phylogenetically conserved integral plasma membrane protein, is implicated as one of the most important factors contributing to tumor cell multidrug resistance. Formalin-fixed, paraffin-embedded normal and neoplastic canine tissues were studied using an avidin-biotin complex technique employing three murine monoclonal antibodies (C494, C219, JSB-1) to different epitopes of the P-glycoprotein molecule. Evaluation of immunostaining of normal canine tissues revealed positive labeling detected by each antibody in the liver, proximal renal tubular epithelium, adrenal cortex, colonic epithelium, and capillary endothelial cells of the brain. A total of 166 tumors of epithelial or mesenchymal origin were evaluated for P-glycoprotein immunoreactivity. Hepatomas (4/4), colorectal adenomas (7/7), colorectal carcinomas (4/4), adrenal cortical adenomas (3/3), hemangiopericytomas (15/15), apocrine gland adenocarcinomas (4/5, 80%), and transitional cell carcinomas (2/2) consistently labeled with at least one of the antibodies. Histiocytomas (0/10), cutaneous plasma cell tumors (0/10), fibromas (0/3), fibrosarcomas (0/4), and leiomyomas (0/4) were uniformly negative with all antibodies. Malignant lymphomas (6/22, 27.3%), malignant melanomas (4/13, 30.8%), leiomyosarcomas (3/6, 50%), mammary gland carcinomas (12/19, 63.2%), mammary gland adenomas (3/9, 33.3%), squamous cell carcinomas (8/10, 80%), basal cell tumors (5/7, 71.4%), apocrine gland adenomas (1/2, 50%), cholangiocarcinomas (2/3, 66.7%), and thyroid gland carcinomas (2/4, 50%) gave variable results. The antibodies C494, JSB-1, and C219 labeled 66/166 (39.8%), 53/166 (31.9%), and 38/166 (22.9%) of all tumors studied, respectively. A total of 26/166 (15.7%), 22/166 (13.3%), and 37/166 (22.6%) of tumors were labeled by all three, just two, or one antibody alone, respectively. The antibody C494 was the only antibody labeling 28/166 (16.9%) of the cases. JSB-1 alone labeled 9/166 (5.4%) of the tumors. C219 failed to label any tumors not also labeled by either C494 or JSB-1. Labeling by C494 was more intense and specific than labeling by the other two antibodies. Results indicate that P-glycoprotein can be detected in routinely processed canine tissues. The detection of P-glycoprotein within canine liver, kidney, adrenal gland, and colon and within tumors arising from these tissues is consistent with that reported in the literature for human tissues. Variable labeling results of other tumors such as malignant lymphoma and mammary gland carcinomas also is consistent with reports of human studies. Detection of multidrug resistance markers such as P-glycoprotein in canine tissues may provide additional information upon which to base a prognosis or to design treatment regimens for canine tumors.

Hypoglycemia associated with a large, gastric leiomyosarcoma was diagnosed in an 11-year-old, yellow Labrador retriever. The dog had persistent hypoglycemia and low serum insulin levels. Although radiological and ultrasonographical evaluations suggested an abdominal mass involving the liver, a large, nonresectable, gastric mass was found during exploratory laparotomy. Metastasis was not identified on gross inspection of the liver or abdomen, and no metastatic lesions were seen on thoracic radiographs. The dog was euthanized. Histopathological examination of the mass revealed a poorly differentiated, gastric leiomyosarcoma that extended into the mesentery without regional lymph-node involvement.

Septic cholangiohepatitis was diagnosed in an 11-year-old Warmblood gelding with a history of intermittent colic and fever. Klebsiella pneumoniae, susceptible to gentamicin, was cultured from the biopsy specimen. However, treatment with gentamicin was unsuccessful, and histologic examination and bacteriologic culture of a biopsy specimen obtained 3 weeks later revealed progression of the hepatic inflammation and yielded growth of gentamicin-resistant K pneumoniae. At this time, several discrete hyperechoic structures, suggestive of biliary calculi, were seen ultrasonographically. A change in antibiotic treatment was associated with gradual resolution of clinical signs. Five months after initial examination, the horse had a sudden onset of severe right forelimb lameness. The horse responded to treatment with antibiotics and phenylbutazone, but lameness and fever that was unresponsive to treatment recurred 7 months later, and the horse was euthanatized. Necropsy revealed nodules throughout the liver and a mass associated with the right metacarpophalangeal joint. Histologic and immunohistochemical examination revealed carcinomatous infiltration of the liver and metacarpophalangeal joint. The tumor was probably of biliary origin. Carcinoma should be considered in cases of septic cholangiohepatitis unresponsive to antibiotic treatment.

Résumé- Un chien, jeune adulte, a été présenté pour une masse sous-cutanée évoluant depuis un mois sur la partie droite du thorax et une masse ulcérée sous-cutanée sur la cuisse droite. L'examen histo-pathologique a révélé une inflammation pyogranulomateuse du derme et du tissu sous-cutané avec de larges hyphes fongiques. De nouvelles lésions sont apparues. Un traitement à base d'itraconazole pendant 2 semaines a été inefficace. L'euthanasie a été pratiquée 10 semaines après la première consultation. La culture fongique faite à partir de prélèvements chirurgicaux a permis d'isoler un Conidiobolus sp. Des infections àConidiobolus sp. ont été rapportées chez l'homme, le cheval, le mouton et le lama. Histologiquement, les hyphes sont difficiles à différencier de ceux d'autres zygomycètes ou de Pythium insidiosum. La culture est nécessaire pour une identification définitive. Une discussion sur les aspects comparés des infections cutanées àConidiobolus sp. est développée. [Hiller, A., Kunkle, G. A., Ginn, P. E., Padhye, A. A. Canine subcutaneous zygomycosis caused by Conidiobolus sp.: a case report and review of Conidibolus infections in other species. (Zygomycose sous-cutanée àConidiobolus sp. chez un chien: cas clinique et revue des infections àConidiobolus dans les autres espèces). Resumen- Un perro adulto joven presentaba una masa subcutánea en la región torácica derecha y otra ulcerada en la parte proximal de la extremidad posterior derecha, ambas de un mes de duración. El exámen histopatológico mostró una inflamación piogranulomatosa de la dermis y del tejido subcutáneo con grandes hifas füngicas. A pesar de que la enfermedad cutánea presentó un curso oscilante, aparecieron nuevas lesiones. Un tratamiento de dos semanas con itraconazol no alteró el curso de la enfermedad. El animal fue eutanasiado a las 10 semanas de la primera visita. Se ais lóConidiobolus sp. a partir de las muestras quirúrjicas. Las infecciones por Conidiobolus sp. estan descritas en la especie humana, la equina, la ovina y en las llamas. Las hifas no se diferencian fácilmente a nivel histológico de otros cigomicetales o de Pythium insidiosum y es necesaria la identificatión mediante un cultivo fúngico para establecer un diagnóstico definitive Se discuten las caracteristicas de la infección cutánea por Conidiobolus sp. y se describen las caracteristicas de la pitiosis cutánea. [Hillier, A., Kunkle, G. A., Ginn, P. E. and Padhye, A. A. Canine subcutaneous zygomycosis caused by Conidiobolus sp.: a case report and review of Conidibolus infections in other species (Cigomcosis subcutánea canina causada por Conidibolus sp.: un caso clinico y revisién de las infecciones por Conidibolus sp. en otras especies). Zusammenfassung- Ein junger ausgewachsener Hund wurde vorgestellt, der seit einem Monat an der rechten Thoraxwand ein subkutanes Gebilde und proximal an der rechten Hintergliedmaße eine ulzer-ierende, subkutane Masse aufwies. Bei der histopathologischen Untersuchung wurde eine pyogranulomatöse Entzündung der Dermis und Subkutis mit breiten Pilzhyphen entdeckt. Trotz des "Auf und Ab" der Hautkrankheit erschionon laufend neue Hautveränderungen. Eine zweiwöchige Behandlung mit Itrakonazol veränderte den Verlauf der Krankheit nicht. 10 Wochen nach der Erstvorstellung des Patienten wurde en euthenesiert. In der Kultur von chrirugischen Proben wurde Conidiobolus sp. isoliert. Conidiobolus sp.-Infektionen sind bei Menschen, Pferden, Schafen und Lamas beschrieben. Die Hyphen können histologisch schlecht von denen anderen Zygomyzeten oder von Pythium insidiosum unterschieden werden. Für die endgültige Diagnose ist eine Identifizierung mittels Pilzkultur notwendig. Die Erscheinungsbilder von kutanen Conidiobolus sp.-Infektionen werdon diskutiert und mit denen kutaner Phytiosis verglichen. [Canine subcutaneous zygomycosis caused by Conidiobolus sp.: a case report and reviews of Conidiobolus infections in other species (Subkutane Zygomykose des Hundes durch Conidiobolus sp.: Fallbericht und übersicht über Conidioblus-Infektionen bie anderen Tierarten). Abstract- A young adult dog was presented with a 1-month history of a subcutaneous mass on the right thoracic wall and an ulcerative, subcutaneous mass of the proximal right hindlimb. Pyogranulomatous inflammation of the dermis and subcutis with broad fungal hyphae were found on histopathologic examination. Despite some waxing and waning of the skin disease, new lesions continued to appear. A 2-week course of itraconazole did not alter the course of the disease. Euthanasia was performed 10 weeks after initial presentation. Conidiobolus sp. was isolated in culture from surgical specimens. Conidiobolus sp. infection has been reported in humans, horses, sheep and llamas. The hyphae cannot be easily distinguished histologically from those of some other zygomycetes or Pythium insidiosum and fungal culture identification of the organism is required for definitive diagnosis. A discussion of the features of cutaneous Conidiobolus sp. infection is given and comparative features of cutaneous pythiosis are presented.

Histologic evaluation of four eyes from three stranded juvenile green turtles (Chelonia mydas) from Florida, USA revealed ocular fibropapillomas composed of an overlying hyperplastic epithelium, various amounts of a thickened, well vascularized, collagenous stroma, and a moderate-to-dense population of reactive fibroblasts. The histologic morphology of the ocular fibropapillomas varied depending on whether the eyelid, conjunctiva, limbus, or cornea was the primary site of tumor origin. Fibropapillomas arising from the limbus, conjunctiva, or eyelid tended to be polyploid or pedunculated with a high degree of arborization. They often filled the conjunctival fornices and extended externally to be ulcerated on the distal aspects. Corneal fibropapillomas were more sessile and multinodular with less arborization. Some corneal tumors consisted primarily of a broad fibrovascular stroma and mild epithelial hyperplasia, whereas others had a markedly hyperplastic epithelium supported by stalks of fibrovascular stromal tissue. In green turtles ocular fibropapillomas may be locally invasive and associated with severe blindness and systemic debilitation.