Avaliação dos efeitos tóxicos induzidos por malation e malaoxon e a possível proteção por oximas

Tese (doutorado) - Universidade Federal de Santa Catarina, Centro de Ciências Biológicas, Programa de Pós-Graduação em Bioquímica, Florianópolis, 2013O malation é um composto tóxico pertencente à classe dos pesticidas organofosforados (OF) que tem como mecanismo primário de ação inibir a enzima acetilcolinesterase (AChE), levando à clássica síndrome colinérgica. No entanto, estudos vêm demonstrando que a neurotoxicidade decorrente da exposição crônica a esta classe de pesticidas pode ocorrer sem sintomas colinérgicos antecedentes e parece não depender da inibição da enzima AChE. Quanto ao tratamento da intoxicação aguda por esses compostos, a eficácia das oximas clinicamente disponíveis (por exemplo, pralidoxima), utilizadas para reativar a AChE inibida, tem sido questionada. Dessa forma, o primeiro objetivo deste estudo foi avaliar a eficácia da pralidoxima e de uma oxima experimental (K074) na reativação da AChE após exposição aguda ao malation, bem como na prevenção de possíveis alterações bioquímicas relacionadas com o estresse oxidativo induzidas pelo malation, utilizando camundongos Swiss. O malation (1,25 g/kg, s.c.) induziu uma diminuição significativa da atividade da AChE no córtex pré-frontal, hipocampo e sangue dos animais 24 h após uma única injeção. Após os tratamentos com as oximas (1/4 da DL50, i.m., 6 h após a exposição ao malation), foi observado que a pralidoxima (66 mg/kg) foi capaz de reverter significativamente a inibição da AChE sanguínea, enquanto que a oxima K074 (5,8 mg/kg) não teve efeitos de reativação em relação à enzima sanguínea. Interessantemente, ambas as oximas testadas foram incapazes de reativar a AChE inibida pelo malation no córtex pré-frontal e no hipocampo após a injeção intramuscular ou intracerebroventricular (1/4 de DL50, 6 h após a exposição ao malation). Os parâmetros bioquímicos relacionados com o estresse oxidativo (atividade das enzimas glutationa peroxidase, glutationa redutase e catalase, bem como os níveis de peroxidação lipídica) não foram afetados nos animais tratados com malation, oximas ou atropina. No entanto, quando a pralidoxima e K074 foram administradas por via intramuscular 6 h após a exposição ao malation, estas oximas foram capazes de aumentar a atividade das enzimas antioxidantes no córtex pré-frontal e hipocampo. Estes resultados indicam que as atividades da AChE periférica e central não estão necessariamente correlacionadas após o tratamento com malation/oximas, além disso, considerando que os tratamentos disponíveis na clínica para a intoxicação com malation não parecem eficazes, este estudo reforça a necessidade de busca por novos reativadores da AChE capazes de reativar eficientemente a enzima sanguínea e cerebral após o envenenamento com malation. O próximo objetivo do trabalho foi investigar os efeitos de administrações repetidas (ao longo de um período de 15 dias) com doses de malation que não causam toxicidade colinérgica, sobre o desempenho cognitivo (relacionado à memória), bem como alterações bioquímicas no hipocampo de camundongos adultos. Os tratamentos com malation (30 e 100 mg/kg, pela via subcutânea) não afetaram o peso corporal dos animais durante o período experimental, além disso, não foram observados sinais evidentes de toxicidade colinérgica durante todo o período de tratamento. Apenas a dose de 100 mg/kg de malation foi capaz de inibir significativamente a atividade da AChE hipocampal após um período de tratamento de 15 dias; no entanto, esta inibição não produziu sinais aparentes de toxicidade. Ao final do tratamento de 15 dias, os animais expostos ao malation (30 e 100 mg/kg) mostraram uma diminuição significativa na capacidade de memória espacial, a qual foi acompanhada por uma diminuição da atividade do complexo I mitocondrial, aumento da expressão das proteínas pró-apoptóticas Bax e Bak, bem como ativação astroglial no hipocampo. Por outro lado, os níveis de sinaptofisina (marcador de sinapses), de colina acetiltransferase (marcador de neurônios colinérgicos) e de aquaporina4 (proteína associada com disfunção da barreira hematoencefálica) não foram alterados pelo tratamento com malation. O déficit no teste de memória espacial de curto prazo causado pela exposição dos animais a 30 mg/kg de malation, dose que não causou inibição da atividade da AChE hipocampal, indica a possibilidade de acontecimentos não colinérgicos relacionados com a modulação da performance cognitiva nestes animais. A partir dos resultados obtidos neste trabalho, sugere-se que o mecanismo envolvido no déficit de memória induzido pela exposição ao malation pode ser mediado, pelo menos em parte, por uma interação sinérgica entre disfunção mitocondrial e processos neuroinflamatórios. Finalmente, a partir de estudos in vitro com cultura primária de neurônios corticais, investigou-se os possíveis mecanismos que precedem a morte celular induzida pela exposição prolongada ao malaoxon. O tratamento com malaoxon 100 µM foi capaz de causar significativa morte das células corticais no dia in vitro 6 (6DIV) e significativa inibição da atividade da AChE nos tempos que precederam a morte celular (0,5 h; 24 h e 48 h). Além disso, observou-se um aumento significativo da produção de espécies reativas de oxigênio e uma diminuição do potencial de membrana mitocondrial nos primeiros 60 min de exposição das células a 100 µM de malaoxon. O pré-tratamento das culturas com o antioxidante ácido ascórbico foi capaz de proteger parcialmente, embora significativamente, da morte celular induzida pela exposição prolongada ao malaoxon. Os nossos resultados indicam que a morte das células neuronais corticais expostas ao malaoxon pode estar associada com indução de estresse oxidativo. No entanto, estudos adicionais são necessários para elucidar os mecanismos envolvidos com a toxicidade do malaoxon neste tipo de cultura, bem como a participação da AChE nestes eventos The organophosphorus (OP) pesticide malathion is a highly neurotoxic compound and its toxicity is primarily caused by the inhibition of acetylcholinesterase (AChE), leading to cholinergic syndrome. However, studies have shown that the neurotoxicity resulting from OP chronic exposure can occur without previous cholinergic symptoms and they do not appear to be dependent on AChE inhibition. Regarding the treatment of OP acute poisoning, the clinical experience with the available oximes (e.g. pralidoxime) is disappointing and their routine use has been questioned. Thus, the first aim of this study was to investigate the potency of pralidoxime and K074 in reactivating AChE after acute exposure to malathion, as well as in preventing malathion-induced changes in oxidative-stress related parameters in mice. Malathion (1.25 g/kg, s.c.) induced a significant decrease in cortico-cerebral, hippocampal and blood AChE activities at 24 h after exposure. Oxime treatments (1/4 of LD50, i.m., 6 h after malathion poisoning) showed that pralidoxime (66 mg/kg) significantly reversed malathion-induced blood AChE inhibition, although no significant effects were observed after K074 treatment (5,8 mg/kg). Interestingly, both oximes tested were unable to reactivate the cortico-cerebral and hippocampal enzymes after intramuscular or intracerebroventricular injection (1/4 of LD50, 6 h after malathion poisoning). Biochemical parameters related to oxidative stress (cerebro-cortical and hippocampal glutathione peroxidase, glutathione reductase and catalase activities, as well as lipid peroxidation) were not affected in animals treated with malathion, oximes or atropine alone. However, pralidoxime and K074, administered intramuscularly 6 h after malathion poisoning, were able to increase the endogenous activities of these antioxidant enzymes in the prefrontal cortex and hippocampus. These results indicate that peripheral and central AChE activities are not necessarily correlated after the treatment of OP compounds and/or oximes. In addition, considering that the available treatments to malathion poisoning appear to be ineffective, the present study reinforce the need to search for potential new AChE reactivators able to efficiently reactivate the brain and blood AChEs after malathion poisoning. The next aim of this study was to investigate the effects of repeated subtoxic doses of malathion (over a 15-days period) on cognitive performance as well as biochemical changes in the hippocampus of adult mice. The treatments with malathion (30 and 100 mg/kg, subcutaneously) did not affect the body weight of animals throughout the experimental period, furthermore, no evident signs of cholinergic toxicity were observed throughout the treatment. The highest dose of malathion (100 mg/kg) was associated with significant AChE inhibition in the hippocampus after a 15-days treatment period, however, this inhibition did not produce signs of cholinergic toxicity. At the end of treatments, malathion-exposed animals (30 and 100 mg/kg) showed a significant impairment on learning-memory ability which was paralleled by a significant decrease in the mitochondrial complex I activity, increase in the levels of proapoptotic proteins (Bax and Bak) and astroglial activation (increase in the level of GFAP), in the hippocampus. On the other hand, the levels of synaptophysin (a specific synaptic marker), choline acetyltransferase (a marker of cholinergic neurons) and aquaporin 4 (a protein related with blood-brain barrier dysfunction), were not affected by the treatment with malathion. The short-term spacial memory deficit observed after the exposure to 30 mg/kg dose of malathion, that caused no hippocampal AChE inhibition, indicates the possibility that cholinergic events are not related with the modulation of the cognitive performance in these animals. From the results obtained in this study, we suggest that the cholinergic system may not be involved in the malathion-induced neurotoxic effects, in addition, we suggest that the mechanism involved in the spacial memory deficit induced by repeated malathion exposure can be mediated, at least in part, by a synergistic interaction between mitochondrial dysfunction and neuroinflammatory processes. Finally, we investigated the possible molecular events that precede malaoxon-induced cell death in cultured neuronal cortical cells. The treatment with 100 µM of malaoxon was able to cause significant death of cortical cells on day in vitro 6 (DIV6) and significant AChE inhibition in the times preceding the cell death (0.5 h, 24 h and 48 h). In addition, there was a significant increase in the production of reactive oxygen species and a decrease in mitochondrial membrane potential in the cells exposed to malaoxon. Pretreatment with the antioxidant ascorbic acid displayed a protective effect against malaoxon-induced neurotoxicity in the cortical neuronal cells. Our data indicate that the neuronal cortical cell death induced by malaoxon may be associated with induction of oxidative stress. However, additional studies are needed to elucidate the mechanisms involved in the malaoxon toxicity in these cells, as well as the involvement of AChE in these events

Efeito reativador de oximas frente à inibição da enzima acetilcolinesterase cerebral induzida pelo malation e malaoxon

Dissertação (mestrado) - Universidade Federal de Santa Catarina, Centro de Ciências Biológicas, Programa de Pós-Graduação em Bioquímica, Florianópolis, 2009.O malation e um pesticida organofosforado (OF) e sua toxicidade depende da sua bioativacao a malaoxon. O envenenamento por malation tem sido tratado com um antagonista do receptor colinergico (atropina) e com oximas (principalmente pralidoxima) em uma tentativa de reativar a acetilcolinesterase (AChE) inibida pelo OF. Contudo, o tratamento com pralidoxima nao tem sido eficiente para reativar a AChE inibida pelo malaoxon e o seu uso rotineiro tem sido questionado. Um dos objetivos deste estudo foi avaliar a potencia in vitro de oximas padrao e de oximas recentemente sintetizadas em reativar a AChE derivada do sobrenadante de cerebro de camundongos, apos inibicao por malaoxon. O malaoxon exibiu um efeito inibitorio dependente da concentracao contra a AChE cerebral de camundongo (IC50 = 3.18 ÊM). A pralidoxima demonstrou um significativo, porem modesto efeito de reativacao da AChE inibida pelo malaoxon (30% de reativacao na concentracao de 600 ÊM). Embora as oximas HI-6 e metoxima exibiram efeitos de reativacao similares quando comparadas com a pralidoxima, as oximas obidoxima e trimedoxima mostraram maior eficacia de reativacao (em torno de 70% de reativacao na concentracao de 600 ÊM). As oximas recentemente desenvolvidas K074 e K075 demonstraram maior efeito de reativacao (em torno de 55% de reativacao na concentracao de 600 ÊM) quando comparadas com a pralidoxima. Os resultados deste estudo mostram que as oximas padrao obidoxima e trimedoxima e as oximas ineditas K074 e K075 apresentam efeitos de reativacao superior da enzima AChE de cerebro de camundongos inibida pelo malaoxon sob condicoes in vitro quando comparadas com a pralidoxima. O segundo objetivo do trabalho foi avaliar o potencial efeito benefico das oximas K074, K075 e trimedoxima na reversao de efeitos deleterios induzidos pela exposicao ao malation na atividade da enzima AChE e em alguns parametros de estresse oxidativo em cortex pre-frontal e hipocampo de camundongos adultos. A administracao de malation (na dose de 1,25 g/kg, s.c.) inibiu significativamente (em torno de 50 %) a atividade da enzima AChE no cortex pre-frontal dos animais 24 h apos a administracao. A oxima padrao pralidoxima (. da DL50 e em combinacao com a atropina) diminuiu significativamente este efeito. A oxima inedita K074 (. da DL50 e em combinacao com a atropina) apresentou baixo efeito de reativacao da AChE, enquanto as outras oximas estudadas (trimedoxima e K075; . da DL50 e em combinacao com a atropina) nao tiveram efeitos reativadores. A atividade da AChE ix hipocampal nao foi inibida apos exposicao aguda ao malation. A exposicao ao malation causou uma diminuicao significativa na atividade glutationa peroxidase e glutationa redutase no cortex pre-frontal doa animais, mas os niveis de glutationa nao foram afetados nesta mesma estrutura. Estes resultados demonstraram que a oxima padrao pralidoxima foi o melhor reativador da AChE inibida pelo malation, enquanto que as oximas ineditas K074 e K075 e a oxima padrao trimedoxima apresentaram somente modesto ou nenhum efeito de reativacao. Esta aparente contradicao entre dados in vitro e in vivo esta provavelmente relacionada com as baixas doses das oximas K074, K075 e trimedoxima usadas no experimento in vivo

The BXD21/TyJ recombinant inbred strain as a model for innate inflammatory response in distinct brain regions

Oxidative stress and inflammatory cytokines affect the human brain, increasing the risk for mood and cognitive disorders. Such risk might be selective to brain-specific regions. Here, we determined whether BXD recombinant inbred (RI) mice strains are more suitable than C57BL/6J mice for the understanding of the relationship between antioxidant response and inflammatory responses. We hypothesized that inflammatory responses could be independent of antioxidant response and be inherent to brain-specific regions. This hypothesis will be addressed by the analyses of mRNA expression. We explored, at 7-months-of-age, the innate activation of proinflammatory cytokines (tumor necrosis factor alpha (TNFα) and interleukin 6 (IL-6), as well as Kelch-like ECH-associating protein 1 (Keap1), nuclear factor erythroid 2 related factor 2 (Nrf2) and glutathione peroxidase 1 (Gpx1) mRNA in both male and female BXD84/RwwJ RI, BXD21/TyJ RI and control strain (C57BL/6J mice). We report that: (1) The cerebellum is more sensitive to antioxidant response in the BXD21/TyJ RI strain; (2) The cerebellum, hippocampus and striatum show increased levels of cytokines in the BXD21/TyJ RI strain; (3) The BXD RI strain has lower brain weight relative to control strain (C57BL/6 mice). In conclusion, our novel data show the utility of the BXD21/TyJ RI strain mice in offering mechanistic insight into Nrf2’s role in the inflammatory system

Probucol e Succinobucol apresentam efeitos hipolipemiantes e antioxidantes similares: um estudo subagudo/subcrônico em camundongos

O probucol e seu monossuccinato, succinobucol, são compostos hipocolesterolemiantes com propriedades antioxidantes e anti-inflamatórias que tem demonstrado resultados promissores em ensaios clínicos de fase III. Evidências têm relatado certas vantagens do succinobucol em relação ao probucol, no que se refere à ausência de efeitos adversos no sistema cardiovascular, tais como o prolongamento da repolarização cardíaca e os riscos de arritmias (observado em humanos tratados com probucol). O objetivo deste estudo foi investigar os efeitos de tratamentos subagudos e crônicos com probucol e Succinobucol em parâmetros bioquímicos (principalmente os níveis de lipídeos plasmáticos) em camundongos, e comparar suas atividades antioxidantes in vitro. Os animais foram tratados com probucol ou succinobucol (10 mg/kg/dia, por via oral) uma vez ao dia, durante 15 (tratamento subagudo) ou 30 dias (tratamento subcrônico). O tratamento subcrônico com os 2 compostos diminuiu significativamente os níveis de colesterol total plasmático. Ambos os tratamentos diminuíram o risco de aterosclerose e aumentaram os níveis de colesterol não HDL e não demonstraram sinais de hepato ou nefrotoxicidade. A atividade sequestradora de radicais livres dos dois compostos (avaliada através do ensaio do DPPH in vitro) não foram significativamente diferentes, sendo similar à do ácido ascórbico. Em conclusão, ambos os compostos, probucol e succinobucol, representam uma importante escolha para futuras aplicações terapêuticas em condições patológicas relacionadas à hipercolesterolemia e estresse oxidativo

Pruning inflorescences reduces the yield of neutral-day strawberry cultivars

The lack of information on inflorescence pruning of strawberry cultivars can compromise fruit yield and quality. The aim of this study was to investigate whether inflorescence pruning intensities interfere with the horticultural potential of strawberry cultivars. The treatments studied were three cultivars (‘Albion’, ‘Monterey’, and ‘San Andreas’) and four inflorescence pruning intensities (no pruning, removal of the first inflorescence, removal of the first two inflorescences, and removal of the first three inflorescences). The experiment was laid out in randomized blocks, with four replications. Fruit production and quality were assessed. ‘Monterey’ produced the most fruit and had the highest total strawberry production. Regardless of the cultivar, the total number of fruits and the total yield decreased linearly as the intensity of inflorescence pruning increased. In conclusion, increasing the intensity of inflorescence pruning reduces the productive potential of strawberry plants. Regardless of pruning, ‘Monterey’ has the best productive performance. The chemical quality of strawberries is not influenced by the pruning and cultivars studied.The lack of information on inflorescence pruning of strawberry cultivars can compromise fruit yield and quality. The aim of this study was to investigate whether inflorescence pruning intensities interfere with the horticultural potential of strawberry cultivars. The treatments studied were three cultivars (‘Albion’, ‘Monterey’, and ‘San Andreas’) and four inflorescence pruning intensities (no pruning, removal of the first inflorescence, removal of the first two inflorescences, and removal of the first three inflorescences). The experiment was laid out in randomized blocks, with four replications. Fruit production and quality were assessed. ‘Monterey’ produced the most fruit and had the highest total strawberry production. Regardless of the cultivar, the total number of fruits and the total yield decreased linearly as the intensity of inflorescence pruning increased. In conclusion, increasing the intensity of inflorescence pruning reduces the productive potential of strawberry plants. Regardless of pruning, ‘Monterey’ has the best productive performance. The chemical quality of strawberries is not influenced by the pruning and cultivars studied

LIDERANÇA: O DESAFIO DAS ENFERMEIRAS RECÉM-FORMADAS

Objective: To identify the challenges faced by the new graduate nurses in leading a group. Methodology: bibliographical research carried out at the BVS. Categories: Leadership styles; Leadership and the importance of the communication; and Leadership and the academic formation of the nurse. Analysis: to exert an efficient leadership style it is necessary to know and to conciliate the maturity level of the led people. Beyond the leadership capacity, the leader must develop communication competencies. When leaving the university, the new nurses don't have a clear definition of their roles, therefore we understand that some changes may be necessary in the formation professionals in order to turn them into leaders. We conclude that the success of a leader depends on the establishment of a relation of trust and respect, and we believe that the leadership is a group process, where influences happen with the purpose to reach a goal, and therefore it is linked to an action meaning, which can be learned. Descriptors: Leadership; Nursing; Organization and Administration.Objetivo: Identificar os desafios das enfermeiras recém-formadas ao liderarem um grupo. Metodologia: pesquisa bibliográfica, realizada na biblioteca virtual de saúde (BVS), utilizando as seguintes bases de dados: BDENF, LILACS e SciELO. Categorias: Estilos de liderança; Liderança e a importância da comunicação; e Liderança e a formação acadêmica do enfermeiro. Análise: para exercer um estilo de liderança eficaz é necessário conhecer e conciliar o nível de maturidade dos liderados. Além da capacidade de liderar, o líder deve desenvolver competências comunicativas. Ao sair da universidade, as recém-enfermeiras não possuem clara definição de seu papel, com isso, compreendemos que haja a necessidade de mudanças na formação profissional para ser uma líder. Concluímos que o sucesso do líder depende do estabelecimento de uma relação de confiança e respeito e que a liderança é um processo grupal, onde ocorrem influências com a finalidade de alcançar uma meta, portanto, está ligado a um sentido de ação, passível de ser aprendido. Descritores: Liderança; Enfermagem; Organização e Administração

Combined Toxicity of Methylparaben and Propylparaben in Artemia salina and Allium cepa Applying Experimental Design

Parabens are used as preservatives in sanitizers and cosmetic products causing environmental concern, because presented potential as endocrine disrupters. Among these compounds, the most used are methylparaben and propylparaben. Thus, a study was proposed to evaluate the interaction between different concentrations (mmol L-1) of the variables methylparaben [MP] and propylparaben [PP], against the acute toxicity of the microcrustacean Artemia salina (A. salina) and Allium cepa (A. cepa) applying the 22 factorial design with an added center point. Responses were used: percent A. salina mortality (% mortality), A. cepa root growth inhibition (% root inhibition) and mitotic index (%MI). For A. salina, after 72 hours of exposure with the combination of concentration ([MP] and [PP] = 0.8 mmol L−1) caused an 80% mortality. While, A. cepa a high cytotoxicity was observed with the mixture of Parabens, exhibiting 72.3% root growth inhibition at [MP] = 1.2 mmol L-1 with [PP] = 1.2 mmol L-1. In contrast, for response %MI at [MP] = 0.3 mmol L-1 with [PP] = 0.3 mmol L-1, 2.5 %MI with 36% inhibition. In this context, parabens demonstrated high toxicity for A. salina and cytotoxicity for A. cepa, based on the interaction with the effect of the concentrations

Analysis of the association between lactotransferrin (LTF) gene polymorphism and dental caries

OBJECTIVE: The present study evaluated the association between lactotransferrin (LTF) gene polymorphism (exon 2, A/G, Lys/Arg) and dental caries. MATERIAL AND METHODS: A convenience sample of 110 individuals, 12 years old, was divided into: group 1, 48 individuals without caries experience (DMFT=0), and group 2, 62 subjects with caries experience (DMFT>;1). DNA was obtained from a mouthwash with 3% glucose solution, followed by a scrapping of the oral mucosa. After DNA purification, polymerase chain reaction (PCR), single strand conformation polymorphism (SSCP) was performed to access the study polymorphism. The LTF A/G (Lys/Arg) polymorphism had been previously reported as located in exon 1. RESULTS: Allele 1 of the study polymorphism was associated with low DMFT index and showed a protective effect against caries experience (OR=0.16, IC=0.03-0.76, p=0.01). CONCLUSIONS: Lactotransferrin A/G (exon 2, Lys/Arg) polymorphism was associated with susceptibility to dental caries in 12-year-old students

Características citológicas de cistoadenocarcinoma papilar ovariano em um cão

Background: Ovarian papillary cystadenocarcinoma is a rare neoplasm associated with peritoneal implantation and malignant effusion. Most dogs are asymptomatic until the nodules become large and the abdominal volume is increased. From the clinical suspicion, the diagnosis can be obtained through imaging and histopathology, however, cytological analysis has become an alternative method for the early detection of this neoplasm. In order to demonstrate the importance of cytology in the diagnosis of ovarian neoplasms and its metastasis, it is reported a case of metastatic ovarian papillary cystadenocarcinoma in a dog.Case: Female, intact, teckel, 5-year-old, with increased abdominal volume. Physical examination revealed ascites and intracavitary mass, abdominocentesis and fine needle puncture of the mass were performed for cytological evaluation. In the cavity fluid it was observed: dark red color, cloudy appearance, hematocrit of 35%; (7.6 g / dL), pH (8.0), 22,000 nucleated cells / μL, marked cellularity of pleomorphic epithelial cells arranged in three-dimensional cohesive groups, sometimes in acinar or tubular pattern, nucleus with loose chromatin coarse, scarse to moderate cytoplasm, perinuclear halo, multiple and evident nucleoli compatible with carcinomatous neoplastic effusion. In the cytological evaluation of the tumor, epithelial cells were observed, with the same microscopic characteristics of the abdominal fluid. A laparotomy that did not show metastasis was performed, multiple nodes interspersed with cystic regions containing yellow-red fluid in the right ovary were visualized. Histopathology showed: neoplastic cells proliferation of ovarian glandular tissue, scarce cytoplasm, poorly delimited, nucleus ranging from oval to cylindrical with marked pleomorphism, evident nucleoli and loose chromatin, mitotic figures and papillary growth. Neoplastic cells forming irregular cavities with proteinaceous fluid, scarce connective tissue intermingling the cellular nest and areas of hemorrhage. Cytological and histopathological analyzes were compatible with ovarian papillary cystadenocarcinoma. After three months of excision, the dog returned with thoracic effusion that presented the same characteristics of the abdominal fluid, indicating metastasis.Discussion: Metastasis and effusion were observed in 48% and 86% of dogs with this tumor, respectively. Cell exfoliation, release of fluid through the tumor capsule or rupture of cysts can result in transcelomic metastatic implants that exert pressure and obstruct peritoneal and diaphragmatic lymphatic vessels causing effusion. The macro and microscopic characteristics of the abdominal effusion reinforced the suspicion of neoplasia, and the cytomorphological evaluation of the tumor, which identified carcinomatous cells similar to that of the effusion, allowed the presumptive diagnosis of the neoplasia. The macroscopic presence of multiple nodes interspersed with cystic regions containing red fluid in the right ovary, identified after surgical excision, reinforced the cytologic diagnosis. Histopathological examination identified wellestablished microscopic features that allowed the definitive and confirmatory diagnosis of neoplasia. Radiological analysis of the chest was not enough to detect the metastasis diagnosed by effusion analysis, however, small nodules (less than 6 mm) are difficult to identify by imaging. Thus, it is important to emphasize the importance of cytological evaluation of tumor and effusions for detection of neoplastic cells for the diagnosis of intracavitary neoplasia and metastasis