Diffuse large B-cell lymphoma affecting the third eyelid of two young adult FeLV-infected cats.

Lymphoma is one of the most frequently diagnosed tumors in FeLV-infected cats. Extranodal lymphomas include lymphomas in ocular and periocular tissues, such as the third eyelid (TEL), which is an uncommonly diagnosed type of lymphoma in cats. This study aimed to describe the clinicopathological features of lymphoma in the TEL of two FeLV-infected cats. A retrospective study in two anatomic pathology laboratories was performed, and two cases met the inclusion criteria. A 4-year-old, female cat (case 1), positive for FIV gp40 antigen and FeLV gp70 antigen by immunohistochemistry (IHC), and a male cat of 22 months old (case 2), positive both serologically for FeLV p27 antigen and for FeLV gp70 antigen by IHC, were referred to veterinary clinics with unilateral swelling and mass in the TEL, which had rapid growth in case 2. Histological and immunohistochemical analysis established the final diagnosis of diffuse large B-cell lymphoma in both cases. The cat in case 2 died 4 months after the diagnosis, with clinical worsening prior to death. Necropsy was not performed in either case, which precluded the definition of a primary or secondary involvement. However, the ocular lesions were the reason for consultation in both cases and it may have been an initial manifestation of a multicentric disease. Thus, FeLV-infected cats with clinical finding of eyelid swelling or mass formation should have lymphoma as a differential diagnosis, and a complete physical examination should be performed to detect extraocular involvement.

Histological and immunohistochemical features of carcinomas with pulmonary involvement in cattle.

Primary pulmonary neoplasms in cattle are rare. There are few studies on the pathological findings of these neoplasms in this species. This study aimed to describe the histological and immunohistochemical findings of primary and metastatic pulmonary carcinomas in cattle. We conducted a retrospective study of 19 cases of epithelial neoplasms with pulmonary involvement. Histologically, most of the neoplasms were classified as primary pulmonary neoplasms, including different adenocarcinoma subtypes (4/19, 21%) and adenosquamous carcinomas (3/19, 16%), followed by squamous cell carcinoma (6/19, 32%), metastatic uterine adenocarcinoma (4/19, 21%), metastatic hepatocellular carcinoma (1/19, 5%), and metastatic cholangiocarcinoma (1/19, 5%). By immunohistochemistry, all neoplasms were positive for pancytokeratin, and 4/19 (21%) were positive for vimentin. Primary pulmonary neoplasms had immunoreactivity for thyroid transcription factor-1 (6/7), while only 2 of these cases were positive for napsin A. All cases with squamous differentiation (9/9) had immunoreactivity for cytokeratin (CK) 5/6, while only 7 of these cases were positive for p40. CK20, CK7, and CK8/18 showed varied immunoreactivity in the primary and metastatic pulmonary carcinomas but were important markers to confirm the diagnosis of primary mucinous adenocarcinoma and metastatic cholangiocarcinoma. HepPar-1 was only positive in the metastatic hepatocellular carcinoma. The limited number of cases of metastatic uterine adenocarcinomas in this study precluded identification of a specific immunophenotype for this tumor. Immunohistochemistry proved to be an important tool to confirm the proper classification of these neoplasms.

Monensin poisoning outbreak in free-ranging and captive birds.

Monensin poisoning is uncommon and has been rarely reported in birds. This work aimed to described clinical-pathological aspects of an outbreak of monensin poisoning in captive and free-ranging birds. Thirty-seven of 600 captive birds fed a diet containing 893.19 mg/kg of monensin died within 10 days (mortality 6.17%). There was no ionophore antibiotics on the feed label supplied to captive birds, which established an error in feed production. Necropsies were performed on twelve animals: Muscovy duck (Cairina moschata) (2/12), greater rhea (Rhea americana) (2/12), black-necked swan (Cygnus melancoryphus) (2/12), garganey (Anas querquedula) (1/12), ostrich (Struthio camelus) (1/12), and common pigeon (Columbus livia) (4/12). These four common pigeons were free-ranging birds and died after eating the same contaminated feed. Birds were mainly found dead, however in animals which clinical signs were observed (Columba livia, Rhea americana, Cairina moschata, Anas querquedula, and Struthio camelus), they included incoordination, inability to stand, and intense prostration, that ranged from 24 to 72 h until death. Grossly, five birds had focally extensive pale firm areas in the myocardium and two had in the skeletal muscles, one being concomitant lesions. Histologically, muscle necrosis and degeneration were observed in striated musculature (skeletal and/or heart) in all birds analyzed. Monensin poisoning outbreaks can affect free-ranging birds that are fed on external feeders, as well as captive birds, due to an error in the feed formulation.

Diseases associated with feline leukemia virus and feline immunodeficiency virus infection: A retrospective study of 1470 necropsied cats (2010-2020).

Feline leukemia virus (FeLV) and feline immunodeficiency virus (FIV) are retroviruses affecting cats worldwide, and the prevalence of infection varies considerably according to the geographic area. We retrospectively described FIV- and FeLV-associated diseases in a population of 1470 necropsied cats, of which 396 (26.9%) were infected with FeLV, 199 (13.5%) with FIV, and 134 (9.1%) with FeLV and FIV concomitantly. Cats infected with FeLV (OR 3.4) and co-infected with FeLV and FIV (OR 1.9) were more likely to have neoplasms. The diagnosis of lymphoma and leukemia was higher in cats infected with FeLV (OR 3.9 and 19.4, respectively) and coinfected with FeLV and FIV (OR 1.9 and 19.3, respectively). The odds of diagnosing bacterial diseases were higher in cats coinfected with FeLV and FIV (OR: 2.8), whereas the odds of viral diseases were higher in those infected with FeLV (OR: 2.8), with 2.2 times more diagnoses of feline infectious peritonitis. Neoplastic and infectious diseases in FIV-infected cats did not differ significantly from those in uninfected cats. According to our results, a high prevalence of retroviral infections was observed in southern Brazil, mainly in relation to FeLV. Infected cats were significantly younger than uninfected cats. The main causes of death associated with FeLV infection and FeLV and FIV coinfection were neoplastic and infectious diseases. In contrast, FIV infection was not associated with any specific condition.

Pathological and etiological characterization of cases of bovine abortion due to sporadic bacterial and mycotic infections.

Opportunistic bacteria and fungi are commonly reported causes of bovine abortion in a small percentage of fetal losses of infectious etiology in cattle. The objective of this study was to characterize the pathological and etiological findings in fetuses aborted due to secondary bacterial and fungal infections submitted for postmortem examination between 2004 and 2019 in the State of Rio Grande do Sul, Brazil. Nineteen cases of bacterial etiology and five cases of fungal etiology were assessed. In cases of bacterial etiology, gross changes were uncommon and two different microscopic patterns were observed: (1) primary bronchopneumonia with occasional dissemination in cases of Staphylococcus sp., Streptococcus sp., and Mannheimia haemolytica infections; and (2) systemic disease with sepsis in cases of Escherichia coli and Listeria sp. infections. Aspergillus sp. was the main fungal agent identified, and cases of mycotic abortion were characterized by placentitis, dermatitis, and pneumonia. Fetal membranes were available for examination in less than half of the submissions (11/24), and placental lesions were observed in all cases. This study reaffirms the importance of postmortem examinations in the determination of causes of fetal loss in cattle and highlights pathological findings commonly observed in fetuses aborted due to sporadic bacterial and fungal agents.

Pathological aspects of cutaneous mast cell tumors with metastases in 49 dogs.

Cutaneous mast cell tumor (MCT) is one of the most frequent cutaneous neoplasms of dogs and may vary from well-differentiated to aggressive tumors with metastasis. The authors retrospectively described the gross and histologic aspects of metastatic MCT in 49 dogs. Primary MCT was most commonly identified in the inguinal region (14/35; 40%), and at necropsy multiple, cutaneous nodules were frequently reported (23/49; 47%). All primary MCT were classified as high-grade neoplasms, and metastases involved the lymph nodes (47/49; 96%), spleen (33/49; 67%), liver (29/49; 59%), bone marrow (20/49; 41%), kidneys (16/49; 33%), and heart (14/49; 29%), while the lungs were less commonly affected (9/49; 18%). The main gross findings included lymphadenomegaly in 47 cases; splenomegaly in 28 cases, with splenic nodules in 13 dogs; hepatomegaly in 28 cases, with white pinpoint foci in 9 cases; nodules on the capsular surface of the kidneys in 9 dogs; and epicardial nodules in 6 cases. Histologically, the lymph nodes were largely obliterated by neoplastic mast cells, while in the spleen, neoplastic cells were multifocally scattered (16/33; 48%), arranged in nodules (10/33; 30%), or obliterated the parenchyma (9/33; 27%). In the liver, the neoplastic cells mainly infiltrated the sinusoids (24/29; 83%), but were also arranged in random nodules (10/29; 34%). Interstitial and nodular metastases were observed in the kidneys and the heart. Grossly unapparent metastases were common in the heart (6/14; 43%), kidneys (4/16; 25%), and lungs (6/9). KIT III and KIT II staining patterns were observed in 29 and 20 cases, respectively.

Pathological and immunohistochemical aspects of acute megakaryoblastic leukaemia in a cat - Short communication.

An adult, mixed-breed, feline leukaemia virus (FeLV-) positive female cat was presented with mucosal jaundice and a history of anorexia and constipation for three days. Physical examination revealed splenomegaly, cachexia, and dehydration. Humane euthanasia was conducted, followed by postmortem examination. Grossly, the cat was icteric, and presented hepatomegaly with multifocal white spots and splenomegaly. Histologically, the bone marrow was nearly completely replaced by a proliferation of megakaryocytes and megakaryoblasts, and there was a proliferation of fibrous connective tissue. Similar neoplastic proliferation was observed infiltrating the liver, lymph nodes, spleen, kidney, skeletal muscle, and lungs. Immunohistochemistry was performed for von Willebrand Factor (VWF), CD79α, CD3, feline immunodeficiency virus, FeLV, and CD61. Marked cytoplasmic labelling was observed in the neoplastic cells for FeLV, VWF and CD61, corroborating the diagnosis of acute megakaryoblastic leukaemia.

Tarsal villonodular tenosynovitis (giant cell tumor of tendon sheath) in a dog / Tenossinovite vilonodular pigmentada (tumor de células gigantes da bainha tendínea) tarsal em um cão

ABSTRACT: A 12-year-old female mixed-breed dog presented with lameness, pain, and an enlarged, non-ulcerated, nodular mass in the region proximal to the tarsal joint of the right pelvic limb. Surgical excision was performed, revealing a 6.5 cm mass adherent to the deep flexor tendon and adjacent tissues. The cut section had cysts filled with blackened clotted material, which exuded reddish serous fluid. Microscopically, the cysts were filled with red blood cells and were either denuded or covered by synoviocytes. In addition, the mass was characterized by marked fibrovascular connective tissue associated with siderophages and multinucleated giant cells. These findings were consistent with those of pigmented villonodular tenosynovitis, a rare condition affecting several animal species and humans.

RESUMO: Uma cadela de 12 anos, sem raça definida, apresentou claudicação, algia e aumento de volume não ulcerado, de aspecto nodular, na região proximal à articulação do tarso do membro pélvico direito. A excisão cirúrgica foi optada e revelou uma massa de 6,5 cm de diâmetro, aderida ao tendão flexor profundo e aos tecidos adjacentes. Ao corte, exsudava líquido seroso avermelhado e cistos preenchidos por material coagulado enegrecido foram observados. Microscopicamente, a massa apresentava formações císticas frequentemente preenchidas por hemácias, que encontravam-se ora revestidas por sinoviócitos, ora desnudas. Havia ainda acentuada quantidade de tecido fibrovascular associado a siderófagos e células gigantes multinucleadas. Esses achados foram consistentes com tenossinovite vilonodular pigmentada, uma rara condição que afeta diversas espécies de animais e humanos.

Pathological, immunohistochemical, and molecular findings of equine protozoal myeloencephalitis due to Sarcocystis neurona infection in Brazilian horses.

Equine protozoal myeloencephalitis (EPM) is an important neurologic disease of horses in the American continent caused by Sarcocystis neurona and Neospora hughesi infection. This study describes the pathological, immunohistochemical, and molecular findings of fatal cases of EPM in southern Brazil. A review was performed on a total of 13 cases compatible with EPM, which were diagnosed by postmortem examination in the period of 2010-2017. Epidemiological information was obtained from necropsy reports. Gross and histological lesions were characterized, and cases were subjected to immunohistochemistry anti-Sarcocystis neurona, Toxoplasma gondii, and Neospora spp. Molecular search was performed using ITS-1 gene PCRs. Microscopic lesions were multifocal in all cases, and more frequently observed in the spinal cord segments and in the rhombencephalon. Intralesional protozoans were histologically detected in five horses, while a positive immunostaining for S. neurona was observed in eleven cases (11/13). Through molecular techniques, six positive cases for the ITS-1 gene were detected, and obtained sequences presented highest similarity with S. neurona. EPM due to S. neurona infection represents an important neurologic disease of horses in Brazil and this disease should be considered as a main differential diagnosis in horses presenting neurologic signs.

Ophthalmopathologic characterization of multicentric or metastatic neoplasms with an extraocular origin in dogs and cats.

OBJECTIVE: To characterize the frequency and distribution of secondary ocular neoplasms in dogs and cats identified during necropsy. METHODS: A retrospective analysis of necropsy records of dogs and cats was conducted, and cases with metastatic/multicentric neoplasms with an extraocular origin, involving the eyes, were selected. RESULTS: From January 2015 to January 2019, we identified a total of 233 dogs and 100 cats with metastatic disease. Of these, 11.6% (27/233) of the dogs and 13% (13/100) of the cats had ocular metastases. Lymphoma was the most common multicentric neoplasm involving the eyes of both species. In dogs, these neoplasms occurred bilaterally, predominantly in the anterior uvea, and were diffuse large B-cell, T-lymphoblastic, peripheral T-cell not otherwise specified, and lymphocytic B-cell lymphomas. In cats, feline leukemia virus (FeLV)-associated T-cell lymphoma was the most common. Mammary carcinoma was the second most common ocular metastatic neoplasm in bitches, with a predominantly unilateral involvement of the uveal tract. In cats, following lymphoma, pulmonary and squamous cell carcinomas were the most common multicentric/metastatic neoplasms of the eyes. Individual cases of cholangiocarcinoma, hemangiosarcoma, and chemodectoma in dogs, as well as mammary gland cribriform carcinoma, salivary gland carcinoma, and histiocytic sarcoma in cats were detected. CONCLUSIONS: The eyes of dogs were mostly affected by lymphoma or mammary gland carcinoma, while those of cats mostly had lymphoma, pulmonary carcinoma, or squamous cell carcinoma as the main metastatic/multicentric neoplasm. To the best of our knowledge, this is the first study to identify intraocular metastatic cholangiocarcinoma and chemodectoma in dogs, aside from identifying salivary gland carcinoma in cats.

Hypertrophic osteopathy in a cat with cardiac interventricular septal defect.

A 3-year-old mixed-breed female cat was diagnosed with a ventricular septal defect of the heart through an echocardiogram. After a 9-month treatment, progressive and diffuse hard thickening of all limbs was observed, which on radiographic examinations, revealed a marked thickening of the long bones. The necropsy findings were limited to the appendicular skeleton and thoracic vertebrae, in addition to a severe cardiac interventricular septal defect and lung edema. The histological evaluation revealed severe replacement of the cortical bone by spongy bone in all bone fragments examined. This is the first report of hypertrophic osteopathy occurring in association with a cardiac malformation in a cat.

Neurotuberculosis in cattle in southern Brazil.

Tuberculosis in cattle is a chronic infectious-contagious disease characterized by the development of nodular lesions (granulomas) in mainly the lungs and regional lymph nodes. It is caused by Mycobacterium tuberculosis complex, an acid-fast bacillus (AFB). Tuberculosis in the central nervous system is a rare condition in cattle. Herein, we describe the clinical and pathological findings of six neurotuberculosis cases in cattle diagnosed in Southern Brazil. The average age of the cattle affected was 12 months, and they varied in breed and sex. The clinical history ranged from 5 to 30 days and was characterized by motor incoordination, opisthotonus, blindness, and progression to recumbency. The cattle were euthanized, and grossly, the leptomeninges at the basilar brain showed marked and diffuse expansion, with nodular yellowish lesions ranging in size. On microscopic examination, there were multifocal granulomas located mainly in the meninges, though sometimes extending to adjacent neuropil or existing as isolated granulomas in neuropil. AFBs were observed in the cytoplasm of epithelioid macrophages and multinucleated giant cells through Ziehl-Neelsen histochemical staining and identified as Mycobacterium sp. through immunohistochemistry.

Identificação e distribuição de lesões cardíacas em bovinos intoxicados por Amorimia exotropica / Identification and distribution of cardiac lesions in cattle poisoned by Amorimia exotropica

Amorimia exotropica é um arbusto escandente que pertence à família Malpighiacea, cujo princípio tóxico é o monofluoracetato de sódio e possui ação cardiotóxica em bovinos. Ela é a única representante, na região Sul do país, do grupo de plantas que causam morte súbita associada ao exercício. Este trabalho identificou e mapeou as lesões cardíacas observadas em bovinos intoxicados naturalmente por A. exotropica. Selecionaram-se nove corações bovinos, provenientes de um surto de intoxicação natural pela planta em uma propriedade de gado de corte do Rio Grande do Sul e procedeu-se o mapeamento de oito regiões topográficas distintas (ápice, ventrículos direito e esquerdo, septo interventricular, músculos papilares direito e esquerdo e átrios direito e esquerdo). À avaliação macroscópica quatro bovinos apresentaram lesão focal e bem delimitada no músculo papilar esquerdo. Estas áreas na histologia correspondiam à necrose de coagulação em diferentes estágios de evolução, similares a infartos. Todos os bovinos apresentavam necrose de cardiomiócitos, caracterizadas por retração e hipereosinofilia citoplasmática e fragmentação celular em todas as áreas amostradas. A severidade da injúria celular foi avaliada pela imuno-histoquímica anti-troponina C, a qual demonstrou acentuada perda e/ou diminuição de marcação citoplasmática em células necróticas. O músculo papilar esquerdo foi a região mais acometida nos casos de intoxicação por Amorimia exotropica...

Amorimia exotropica is a shrub of the Malpighiacea family that contains sodium monofluoroacetate as the toxic principle, which has a cardiotoxic action in cattle. In Southern Brazil it is the only species of the group of plants that causes "sudden death during exercise". This study has identified and mapped cardiac lesions observed in cattle naturally poisoned by A. exotropica. An outbreak of poisoning by the plant occurred in a beef cattle herd in Rio Grande do Sul, where nine bovine hearts were selected for examination and mapping of eight distinct topographical regions (apex, right and left ventricles, interventricular septum, right and left papillary muscles , right and left atrium). At gross examination, four cattle showed focal and well-defined lesions in the left papillary muscle. This corresponds to areas of coagulation necrosis in different stages of evolution on histology, similar to infarcts. All hearts showed cardiomyocytes necrosis, characterized by shrinkage and hypereosinophilic cytoplasm and cellular fragmentation in all sampled areas. The severity of cellular injury was evaluated by immunohistochemistry anti-troponin C, which showed marked decrease of cytoplasm staining in necrotic cells. The left papillary muscle was the most affected region in cases of poisoning by A. exotropica...

Novos aspectos sobre a intoxicação por Trema micrantha (Cannabaceae) em equídeos / New aspects of Trema micrantha (Cannabaceae) poisoning in equids

Trema micrantha é uma planta arbórea distribuída amplamente no Brasil. Descrevem-se nesse trabalho novos aspectos epidemiológicos e patológicos relacionados com a intoxicação por essa planta em equídeos. Dois equinos adultos da raça Crioula e dois asininos, de localidades distintas, foram intoxicados naturalmente por Trema micrantha, após consumirem grande quantidade da planta que ficou disponível a eles após uma poda. Além disso, um cavalo adulto, de outra propriedade, que estava passando por restrição alimentar, se intoxicou após consumir as partes baixas de um grande número de árvores jovens de T. micrantha. Clinicamente, em todos os equídeos a doença se caracterizou por alterações neurológicas, que apareceram três a quatro dias após o consumo da planta, com curso clínico de dois a quatro dias (abreviadas por eutanásia). Os principais achados de necropsia foram observados no fígado, que estavam levemente aumentados e com padrão lobular evidente e no sistema nervoso central (SNC), com múltiplas áreas amareladas, focos de malacia e hemorragia, principalmente, no tronco cerebral e cerebelo. Histologicamente, havia necrose hepática aguda, edema acentuado no SNC com degeneração fibrinoide da parede de vasos associada a hemorragia e trombose e, frequentemente, com infiltrado de neutrófilos. Outras alterações observadas nos encéfalos foram: grande quantidade de astrócitos de Alzheimer tipo II na substância cinzenta, acúmulos de células Gitter e degeneração Walleriana próxima a focos de lesões vasculares.

Trema micrantha is a tree widely distributed in Brazil. This paper describes new epidemiological and pathological aspects of this plant poisoning in equids. Two adult horses, Criollo breed and two donkeys from different locations were naturally poisoned by Trema micrantha after consuming large amounts of the plant which was available to them due to pruning. Also an adult horse from another ranch, which was undergoing dietary restriction, was poisoned after consuming the lower parts of a large number of young T. micrantha trees. Clinically, in all cases, the disease was characterized by neurological symptoms that started 3 to 4 days after consumption of the plant, with a clinical course that varied 2 to 4 days (abbreviated by euthanasia). The main gross findings were in the liver, which had slightly increased lobular pattern evident, and in the central nervous system (CNS) with multiple yellowish areas, foci of malacia and hemorrhage, especially in the brainstem and cerebellum. Histologically, there was acute liver necrosis with marked edema of the CNS with fibrinoid vessel wall degeneration, hemorrhage and thrombosis as well as neutrophil infiltration. Other changes in the brain were Alzheimer type II astrocytes in the gray matter, accumulation of Gitter cells and Wallerian degeneration near to vascular lesion foci.

Perfuração de úlcera gastroduodenal em felino – relato de caso / Gastroduodenal perfuration ulcer in a cat – case report

As úlceras gastroduodenais são incomuns em gatos e suas causas ainda não estão bem esclarecidas (LIPTAK et al., 2002; CARIOU et al., 2010). Contudo, elas podem estar associadas a neoplasias, anti-inflamatórios não esteroidais, estresse, hiperacidez gástrica, hipovolemia, falência renal, endoparasitas e intoxicações (LIPTAK et al., 2002; NELSON e COUTO, 2006; CARIOU et al., 2010). O presente estudo tem como objetivo relatar um caso de úlcera gastroduodenal em felino.

Malignant peripheral nerve sheath tumor as a cause of chronic cardiac insufficiency in cattle.

Chronic cardiac insufficiency was associated with a malignant peripheral nerve sheath tumor in a cow. An eight-year-old cow developed a progressive condition (over a period of three months) characterized by an enhanced abdominal volume, reluctance to move, a positive jugular pulse, watery diarrhea and death. At necropsy, moderate subcutaneous edema and an enhanced hepatic lobular pattern were observed. A 23x20x11 cm firm, grayish-white mass adhered to and infiltrated the right atrium. Multiple firm, yellowish-white nodules of 0.5 to 12 cm in diameter were diffusely scattered in the epicardium and parietal pericardium. Histologically, the tumor was poorly circumscribed with foci of infiltration of the myocardium. The neoplastic cells had two major histologic patterns, Antoni types A and B. Within occasional foci, pleomorphic cells with an epithelioid appearance were present in addition to multinucleated cells with periodic acid Schiff (PAS)-positive cytoplasmic globules. Foci of cartilaginous and granular differentiations were interspersed among the neoplastic cells. Multiple vessels presented wall hyalinization and tumoral embolus. Large necrotic foci with mineralization and cholesterol clefts were also observed. Immunohistochemically, the tumor was positive for S100 protein, vimentin and neuron-specific enolase labeling.

Decreased expression of cardiac troponin C is associated with cardiac lesions in Amorimia exotropica poisoned cattle / Expressão diminuída de troponina cardíaca C associada com lesões cardíacas em bovinos intoxicados por Amorimia exotropica

The plants which cause sudden death of cattle in Brazil occupy a leading position for losses in the cattle industry. Amorimia exotropica is one of the plants pertaining to this group. Diagnostic findings in these cases may be inconclusive; further knowledge is necessary. This paper identifies cardiac lesions through anti-cardiac troponin C (cTnC) immunehistochemistry performed in tissues from cattle poisoned after consumption of A.exotropica in southern Brazil. Heart fragments from nine A. exotropica-poisoned cattle were studied immunohistochemically using anti-human cTnC as the primary antibody. In the hearts from all of the poisoned cattle, there was a sharp decrease in the cTnC expression level in the cytoplasm of groups of cardiomyocytes. A significant decrease in anti-cTnC immunoreactivity occurred particularly in degenerated or necrotic cardiomyocytes. Occasional groups of cells showed complete loss of immunolabeling. In the remaining intact cardiomyocytes from poisoned cattle and in cardiomyocytes from six cattle that died from other causes there was intense cytoplasmic staining.

No Brasil, plantas cujo consumo determina morte súbita de bovinos estão entre as principais causas de perdas na pecuária. Esse trabalho identifica lesões cardíacas através de imuno-histoquímica antitroponina cardíaca C (TncC), desenvolvida em tecidos de bovinos intoxicados após consumo de Amorimia exotropica, no sul do Brasil. Fragmentos cardíacos de nove bovinos intoxicados, naturalmente, por Amorimia exotropica foram examinados por imuno-histoquímica anti-TncC, como anticorpo primário. Nos corações de todos os bovinos intoxicados pela planta, havia pronunciada diminuição dos níveis de expressão de TncC no citoplasma de grupos de cardiomiócitos. Diminuição significativa na imunorreatividade anti-TncC ocorreu, particularmente, em cardiomiócitos degenerados ou necróticos. Grupos ocasionais de células mostraram completa perda de imunomarcação. Em cardiomiócitos remanescentes e intactos de bovinos intoxicados e em cardiomiócitos de seis bovinos que morreram por outras causas, observou-se intensa coloração citoplasmática.