Immunolabelling of Acetylated Histones 3 and 4 and Histone Deacetylases 1, 2 and 6 in Canine Soft Tissue Sarcomas.

The objective of this study was to investigate the immunolabelling of acetylated histones and histone desacetylase (HDAC) enzymes in canine soft tissue sarcomas (STSs) and to correlate them with histological and clinical features in order to identify possible prognostic and therapeutic targets in these neoplasms. Fifteen canine STS samples were evaluated and were submitted to immunohistochemistry for acetylated histones 3 (H3) and 4 (H4) and deacetylating enzymes (HDAC1, HDAC2 and HDAC6). Intense immunolabelling of H4 was seen in comparison with H3. A strong positive correlation was observed between the H3 intensity score and the number of mitotic figures (P = 0.004, r = 0.7). Intense immunolabelling of HDAC1 was found in comparison to the expression of HDAC2 and HDAC6 in the evaluated STSs. This finding suggests that HDAC1 may be a potential target for HDAC inhibitors in STSs in dogs.

Mesenteric metastasis of granulosa cell tumor in a bitch: a case report / Metástasis mesentérica de tumor de células de granulosa en una perra: reporte de caso / Metástase mesentérica de tumor das células da granulosa em uma cadela: relato de caso

Abstract Anamnesis: A 5-year-old mixed breed entire bitch was presented with bloody vaginal discharge and abdominal distension. Clinical and laboratory findings: Physical examination and abdominal ultrasonography suggested the presence of a left ovarian tumor. At histopathological examination it was diagnosed as granulosa cell tumor. Treatment approach: An exploratory laparotomy was performed followed by ovariohysterectomy to remove the intra-abdominal mass. Conclusion: The clinical, ultrasonographic and histologic signs in this case support other literature reports. Ultrasonography, in combination with histopathologic analysis is a fundamental tool for detection of ovarian tumors, especially tumors of the granulosa cells.

Resumen Anamnesis: Una perra entera sin raza definida, con cinco años de edad, presentando secreción vaginal sanguinolenta con una distensión abdominal acentuada. Hallazgos clínicos y de laboratorio: El examen clínico y la ultrasonografía abdominal sugirieron la presencia de la neoformación ovárica izquierda. En el examen histopatológico fue diagnosticado como tumor de células de la granulosa. Aproximación terapéutica: Se realizó una laparotomía exploratoria seguida de ovariohisterectomía para eliminar la masa intra-abdominal. Conclusión: Los signos clínicos, ecográficos e histológicos en este caso respaldan otros informes de la literatura. La ecografía, en combinación con el análisis histopatológico, es una herramienta fundamental para la detección de tumores ováricos, especialmente tumores de las células de la granulosa.

Resumo Anamnese: Uma cadela sem raça definida, com cinco anos de idade, não castrada, apresentando secreção vaginal sanguinolenta com acentuada distensão abdominal. Achados clínicos e laboratoriais: O exame clínico e ultrassonografia abdominal sugeriram a presença de neoformação ovariana esquerda. No exame histopatológico foi diagnosticado como tumor de células da granulosa. Abordagem terapêutica: Foi realizada laparotomia exploratória seguida de ovariohisterectomia para remoção da massa intra-abdominal. Conclusão: Os sinais clínicos, ultrassonográficos e histológicos corroboram a literatura, concluindo que a modalidade ultrassonográfica, em associação a análise histopatológica é uma ferramenta fundamental na detecção de neoformações ovarianas, contribuindo significativamente no diagnóstico final.

Effects of canine adipose-derived mesenchymal stem cells on the epithelialization of rabbits' skin autograft (Oryctolagus cuniculus) / Efeitos das células-tronco mesenquimais derivadas do tecido adiposo de cães na epitelização de autoenxertos de pele em coelhos (Oryctolagus cuniculus)

The present study aimed to evaluate the effects of mesenchymal stem cells derived from canine adipose tissue in the healing process of full-thickness mesh skin grafts in rabbits. The stem cells were collected from young dogs; and, after characterization, remained in cryopreservation, in independent doses containing 2 x 106 cells. The mesh distal limb graft technique was performed in 60 rabbits, divided into three groups, CG (Control Group), GT1 (Intralesional Stem Cell Treated Group), and GT2 (Intravenous Stem Cell Treated Group), containing 20 animals each. After grafting, each group was randomly divided into four subgroups according to euthanasia time 3, 7, 14, and 30 days, containing five animals in each group. Animals of GT1_14, GT1_30, and GT2_14, GT2_30 subgroups received a second dose of xenogeneic cells on the seventh day. Meanwhile, animals from GT1_30 and GT2_30 received the third dose of xenogeneic cells on day 14. The groups treated with xenogeneic stem cells positively affected type III collagen re-epithelialization and deposition, and possibly GT1 had a controlled inflammatory response. However, no effect on angiogenesis. Thus, it was possible to demonstrate tolerance and therapeutic action of mesenchymal stem cells from canine adipose tissue in skin grafts in rabbits.(AU)

O presente estudo teve como principal objetivo avaliar os efeitos das células-tronco mesenquimais derivadas do tecido adiposo de cães no processo de cicatrização de autoenxertos de pele de espessura total em malha em coelhos. As células-tronco foram coletadas de cães jovens, após a caracterização estas permaneceram em criopreservação, em doses individuais contendo 2 x 106 células. A técnica de enxerto em malha na região distal do membro foi realizada em 60 coelhos, divididos em três grupos, GC (Grupo Controle), GT1 (Grupo tratado com células-tronco intralesional) e GT2 (Grupo tratado com células-tronco via endovenosa), contendo 20 animais cada. Imediatamente após a enxertia, cada grupo foi dividido aleatoriamente em quatro subgrupos, de acordo com o tempo de eutanásia 3, 7, 14 e 30 dias contendo cinco animais cada. Animais dos subgrupos GT1_14, GT1_30 e GT2_14, GT2_30 receberam uma segunda dose de células xenógenas no sétimo dia. Ademais, animais do GT1_30 e do GT2_30 receberam a terceira dose de células xenógenas no dia 14. Os grupos tratados com células-tronco xenógenas tiveram um efeito positivo na reepitelização e deposição de colágeno tipo III, e possivelmente, o GT1 teve uma resposta inflamatória controlada, entretanto o efeito na angiogênese não foi observado. Dessa forma, foi possível demonstrar que houve tolerância e ação terapêutica das células-tronco mesenquimais derivadas do tecido adiposo de cães em enxertos de pele em coelhos.(AU)

Liquid biopsy based on small extracellular vesicles predicts chemotherapy response of canine multicentric lymphomas.

Lymphoma is the most common type of canine hematological malignancy where the multicentric (cMCL) form accounts for 75% of all cases. The standard treatment is the CHOP chemotherapy protocols that include cyclophosphamide, doxorubicin, vincristine and prednisone, where the majority of dogs achieve complete/partial response; however, it is very important to predict non-responsive cases to improve treatment and to develop new targeted therapies. Here we evaluate a liquid biopsy approach based on serum Small Extracellular Vesicles enriched for exosomes (SEVs) to predict cMCL chemotherapy response. Nineteen dogs at the end of the 19-week chemotherapy protocol (8 Complete Response and 11 Progressive Disease) were evaluated for serum SEVs size, concentration and screened for 95 oncomirs. PD patients had higher SEVs concentration at the diagnosis than CR patients (P = 0.034). The ROC curve was significant for SEVs concentration to predict the response to CHOP (AUC = 0.8011, P = 0.0287). A potential molecular signature based on oncomirs from SEVs (caf-miR-205, caf-miR-222, caf-mir-20a and caf-miR-93) is proposed. To the best of our knowledge, this is the first study demonstrating the potential of a liquid biopsy based on SEVs and their miRNAs content to predict the outcome of chemotherapy for canine multicentric lymphomas.

Comparison of two different doses of bleomycin in electrochemotherapy protocols for feline cutaneous squamous cell carcinoma nonsegregated from ultraviolet light exposure.

Cutaneous squamous cell carcinoma (cSCC) is one of the most common skin tumors in cats due to chronic exposure to ultraviolet light. Local treatments such as electrochemotherapy (ECT) promote disease control or even complete remission. We hypothesize that cats could benefit from treatments using bleomycin at reduced dosages. A prospective nonrandomized single-blind study evaluated the clinical parameters, site lesion, staging, disease-free interval (DFI) and survival time by comparing the standard dose of bleomycin (15,000 UI/m2) (n = 22) with a reduced dose (10,000 UI/m2) (n = 34) in cats with cSCC that underwent ECT as the sole treatment modality. No statistically significant difference in DFI or overall survival was observed between the 2 groups. A higher DFI was found in cats with a small tumor size (less than 0.33 cm3) compared with that for cats with a large tumor size (P = 0.045). Furthermore, a reduced overall survival time for cats with a higher stage in the standard group SG (T3 and T4) (P = 0.004) was observed when compared to that for cats with a lower stage (T1 and T2). In conclusion, ECT using both doses of bleomycin may achieve the same response rate in terms of the overall response, DFI, and overall survival.

Recurrent horizontal transfer identifies mitochondrial positive selection in a transmissible cancer.

Autonomous replication and segregation of mitochondrial DNA (mtDNA) creates the potential for evolutionary conflict driven by emergence of haplotypes under positive selection for 'selfish' traits, such as replicative advantage. However, few cases of this phenomenon arising within natural populations have been described. Here, we survey the frequency of mtDNA horizontal transfer within the canine transmissible venereal tumour (CTVT), a contagious cancer clone that occasionally acquires mtDNA from its hosts. Remarkably, one canine mtDNA haplotype, A1d1a, has repeatedly and recently colonised CTVT cells, recurrently replacing incumbent CTVT haplotypes. An A1d1a control region polymorphism predicted to influence transcription is fixed in the products of an A1d1a recombination event and occurs somatically on other CTVT mtDNA backgrounds. We present a model whereby 'selfish' positive selection acting on a regulatory variant drives repeated fixation of A1d1a within CTVT cells.

Evaluation of angiogenesis, inflammation, and healing on irradiated skin graft with low-level laser therapy in rats (Rattus norvegicus albinus wistar).

The reconstructive techniques have been widely used in Veterinary Medicine. The post-operative adjuvants therapies like the low-level laser therapy (LLLT) are used to decrease inherent complications to reconstructive surgeries. This article purposed to define the LLLT effects on the healing, inflammation, and vascularization of the skin grafts in applicable time intervals to veterinary surgical routine. Forty rats (Rattus norvegicus albinus wistar) were used and each one was submitted to autogenous cutaneous mesh grafting in the interescapular region. The rats were randomly distributed in five groups (G1, G2, G3, G4, and G5) in accordance with the 6 J/cm2 or 10 J/cm2 dose every 3 or 5 days. These treatments were applied on the skin graft for 15 days. The histochemical evaluation with Picrosirius showed greater expression of collagen type 1 - red in grafts of G5 (p < 0.05), while in G1 did not; the expression of collagen type III - green was not induced by LLLT. The histochemical evaluation with hematoxylin-eosin showed greater numbers of fibroblasts in grafts of G4 (p < 0.05) and less hemorrhage in grafts of G5 (p < 0.05). There was modulation of the inflammatory response in irradiated skin grafts. It is concluded the exhibition of the skin grafts to 6 J/cm2 or 10 J/cm2 dose every 5 days improved the healing and the modulation of the local inflammation.

Electrochemotherapy induces tumor regression and decreases the proliferative index in canine cutaneous squamous cell carcinoma.

Canine cutaneous squamous cell carcinoma (cSCC) is the most common skin cancer in dogs, and, due to its low metastatic rate, local treatments, such as electrochemotherapy (ECT), promote disease control or even complete remission (CR). This study aimed to evaluate the gene and protein expression of Bcl-2 and Bcl-2 associated X protein (BAX), the proliferative index and clinical parameters in dogs with cSCC subjected to ECT. A prospective nonrandomized clinical study was performed using dogs with naturally occurring cSCC that was treated with ECT. Eighteen lesions from 11 dogs were selected. The tumor size at day 0 (D0) had no impact on survival or prognosis (P > 0.05). Tumor samples had a lower proliferative index after ECT (D21) than before ECT (P = 0.031). The survival of subjects with Ki67 values lower and higher than the Ki67 median value were not significantly different (P > 0.05). Regarding apoptotic markers, there were no significant differences in the gene and protein expression levels of BAX or Bcl-2 at D0 and D21 (P > 0.05) or in the overall survival of subjects with different levels of apoptotic markers. In conclusion, there was no change in BAX or Bcl-2 gene and protein expression in response to ECT at the time points evaluated, but ECT was able to reduce tumor volume and cellular proliferation in cSCC.

A new experimental model of intrinsic denervation in ileum from wistar rats through intramural microinjections of benzalkonium chloride / Um novo modelo experimental de desnervação intrínseca em íleo de ratos wistar através de micro injeções intramurais de cloreto de benzalcônio

Extensive literature is available about the intrinsic denervation of segments of the digestive tube through the application of CB in the serosa of the viscera. However, this technique has some disadvantages like causing peritonitis, flanges and high mortality, limiting its use in humans. The aim of the present study was to evaluate the feasibility of benzalkonium chloride (CB) to induce intrinsic chemical denervation, through applications of CB in the intramural ileum of wistar rats, as well as deepen the knowledge about the evolution of neuronal injury caused in the process. We used 40 rats, divided into two groups (control-GC and benzalkonium-GB) of 20 animals each, divided into four sub-groups according to the time of postoperative assessment of 24, 48 hours, 30 and 90 days. The animals were submitted to intramural microinjections of sterile saline solution 0.9% (GC) or benzalkonium chloride (GB) in ileal portion, and subsequent histopathological analysis and immunohistochemistry for evaluation of neuronal injury. A significant decrease (p<0.05) was found of the neuronal myenteric count over time in groups, GB3, GB4 and GB2. The specific positive immunolabeling for H2AX and Caspase-3 confirmed the results obtained in the histopathological evaluation, denoting the ignition of irreversible cell injury in 24 hours, evolving into neuronal apoptosis in 48 hours after application of the CB 0.3%. Under the conditions in which this work was conducted, it can be concluded that the application of CB 0.3% by means of microinjections intramural in the ileal wall is able to induce intrinsic chemical denervation of the diverticulum of wistar rats and that the main mechanism of neuronal death is induction of apoptosis.(AU)

Existe vasta literatura sobre a desnervação intrínseca de segmentos do tubo digestório através da aplicação de CB na serosa da víscera. Entretanto, essa técnica tem a desvantagem de causar peritonite, formação de bridas e alta mortalidade, não sendo factível para eventuais utilizações em humanos. O objetivo do presente estudo foi avaliar a viabilidade do Cloreto de benzalcônio (CB) induzir desnervação química intrínseca, por meio de aplicações intramurais em íleo de ratos wistar, além de aprofundar o conhecimento sobre a evolução da lesão neuronal causada neste processo. Foram utilizados 40 ratos, distribuídos em dois grupos (controle- GC e benzalcônio- GB) de 20 animais cada, subdivididos em quatro subgrupos de acordo com o tempo de avaliação pós-operatória de 24, 48 horas, 30 e 90 dias. Os animais foram submetidos à microinjeções intramurais de solução salina estéril 0,9% (GC) ou de cloreto de benzalcônio (GB) em porção ileal, e posterior análise histopatológica e imuno-histoquímica, para avaliação da lesão neuronal. Houve diminuição significativa (p<0,05) na contagem neuronal mientérica ao longo do tempo nos grupos GB2, GB3 e GB4. A imunomarcação específica positiva para H2AX e Caspase-3 confirmou os resultados obtidos na avaliação histopatológica, denotando início da lesão celular irreversível em 24 horas, evoluindo para apoptose neuronal em 48 horas após a aplicação do CB 0,3%. Nas condições em que este trabalho foi conduzido, é possível concluir que a aplicação de CB 0,3% por meio de microinjeções intramurais na parede ileal é capaz de induzir desnervação química intrínseca da porção ileal de ratos wistar e que o principal mecanismo de morte neuronal é a indução de apoptose.(AU)

Mastocitoma cutâneo canino: estudo retrospectivo dos casos atendidos pelo Serviço de Oncologia do Hospital Veterinário da FCAV-Unesp, Campus Jaboticabal, de 2005 a 2015 / Canine cutaneous mast cell tumors: retrospective study of cases attended by the oncology service at the Veterinary Hospital of FCAV-Unesp, Jaboticabal, from 2005 to 2015

Este estudo teve como objetivo analisar os casos de mastocitomas cutâneos em cães atendidos no Hospital Veterinário Governador Laudo Natel da Faculdade de Ciências Agrárias e Veterinárias (FCAV) Unesp Câmpus Jaboticabal, no período de 2005 a 2015, além de avaliar a ocorrência dessa neoplasia em relação à raça, sexo e idade; determinar as regiões corpóreas mais acometidas e as características neoplásicas observadas, assim como, os métodos de diagnóstico mais utilizados no setor, estabelecer os principais graus histológicos diagnosticados e os tratamentos preconizados, verificar alterações de tamanho em relação aos linfonodos, à taxa de recidiva, metástase e possíveis associações entre as variáveis consideradas. Foram avaliados 192 prontuários clínicos de pacientes e observou-se que os cães sem raça definida (SRD) (n=46, 23,96%) foram os mais acometidos, seguidos por cães da raça Boxer (n=40, 20,83%) e Pit bull (n=27, 14,06%). A maioria dos cães eram fêmeas (n=107, 55,7%), e com idade de 7 a 11 anos (n=120, 62,5%). Do total, 32 pacientes apresentaram (16,7%) tumores localizados em membro pélvico, seguidos por nódulos em membro torácico (10,4%, n=20). Sessenta e cinco animais possuíam nódulos ulcerados (33,9%), sendo 96 nódulos de consistência firme (50%). Setenta e seis animais apresentavam múltiplos nódulos (39,6%) e aqueles acima de três centímetros perfaziam 39,1% da amostra (n=75). O método mais utilizado para o diagnóstico foi a punção aspirativa por agulha fina associado à histopatologia (HT), totalizando 39,8% dos nódulos (n=66), seguido pela HT com 37,3% (n=62). Em relação às variáveis histológicas, 18 pacientes apresentaram grau I (11,8%), 112 com grau II (73,7%) e 22 com grau III (14,5%) de acordo com Patnaik et al. (1984). Segundo a classificação de Kiupel et al. (2011), 37 casos foram classificados como de alto grau (35,2%) e 68 como sendo de baixo grau (64,8%). Foi observada associação estatística quando se avaliou a presença de nódulos solitários/múltiplos e o grau histológico, segundo Patnaik et al. (1984) (p=0,008) e Kiupel et al. (2011) (p=0,004), sendo que nódulos com piores características prognósticas eram mais frequentes nos animais diagnosticados com múltiplos nódulos, independente da classificação histológica empregada. Também foi observada a associação entre a presença de nódulos múltiplos com estadio II ou IV (p<0,001) e com a presença de recidiva (p=0,001). Em relação à classificação histológica de Kiupel et al. (2011) foi possível observar associação estatística entre o grau histológico e o tamanho do tumor (p=0,001), a consistência (p=0,028) e a velocidade de crescimento do nódulo (p<0,001); aumento de linfonodo (p<0,001) e o tratamento empregado (p=0,002). Nódulos com tamanho superior a três centímetros (56,8%, n=21) e de crescimento rápido (52,9%, n=36%), eram mais frequentes nos tumores de alto grau. Aumento de linfonodo (80,6%, n=25) e tratamento quimioterápico (83,3%, n=5) também estavam associados a pacientes com alto grau histológico. Em relação à classificação de Patnaik et al. (1984), as variáveis raça e sexo diferiram proporcionalmente entre os grupos histológicos (p=0,008 e 0,040 respectivamente), sendo que o aumento do linfonodo e o crescimento rápido do tumor também tiveram associação com o grau histológico (p=0,002 e 0,001). Quase a metade dos pacientes (47,4%) foi submetidas ao tratamento cirúrgico e quimioterápico (n=91), sendo que em 31,3% (n=60) dos pacientes realizou-se apenas o procedimento cirúrgico. Sessenta e um animais (31,8%) apresentaram aumento de tamanho em linfonodos regionais (31,8%), sendo que 71,9% dos nódulos avaliados tiveram crescimento rápido. O tempo de evolução clínica do tumor foi menor ou igual a um ano, em 158 pacientes (82,3%), seguido por 25 pacientes (13%) com evolução de 1 a 2 anos. Foram observados 66 casos (40,5%) de recidiva e 16 (8,3%) de metástase à distância. Com este estudo, pode-se concluir que cães sem raça definida são os mais acometidos pelo mastocitoma cutâneo, na região de Jaboticabal, seguido por cães da raça Boxer, com idade variando entre 7 e 11 anos, não sendo observada predileção sexual; os nódulos encontrados eram predominantemente não ulcerados, solitários e menores que três centímetros; a maioria dos pacientes apresentou mastocitoma grau II, segundo Patnaik et al. (1984) e baixo grau segundo Kiupel et al. (2011); não se observou recidiva, em sua maioria, nem metástase em linfonodos e/ou a distância; o diagnóstico mais utilizado foi a punção aspirativa por agulha fina associada à histopatologia; a localização dos nódulos era mais prevalente nos membros pélvicos e torácicos, seguido por cabeça e pescoço. A consistência dos nódulos era de apresentação firme ou macia; e a metade dos pacientes foi submetida ao procedimento cirúrgico associado à quimioterapia antineoplásica.(AU)

This study analyzed the cases of cutaneous mastocytomas in dogs seen at the Governador Laudo Natel Veterinary Hospital of the College of Agrarian and Veterinary Sciences (FCAV), Unesp, in Jaboticabal, from 2005 to 2015. The objective was to determine the occurrence of this neoplasm regarding breed, sex, and age, the most affected body parts and observed neoplastic characteristics; the most widely used diagnosis methods, the main histological grades and recommended treatments, to evaluate size changes in relation to lymph nodes, recurrence rate, metastasis and to verify possible associations between the evaluated variables. The clinical files of 192 patients were evaluated. The most affected dogs were of mixed breed (n=46, 23.96%), followed by Boxer (n=40, 20.83%) and Pitbull (n=27, 14.06%). Most of the dogs were females (n=107, 55.7%), aged between 7 and 11 years old (n=120, 62.5%). Thirty-two patients had (16.7%) tumors located in the pelvic limb, followed by thoracic limbs (10.4% n=20). Sixty-five animals had ulcerated nodules (33.9%), of which 96 had firm consistency (50%). Seventy-six animals had multiple nodules (39.6%), and 39.1% of the sample (n=75) had nodules larger than three centimeters. The most used diagnosis method was fine needle aspiration together with histopathology (HT), totaling 39.8% of nodules (n=66), followed by HT in 37.3% of the patients (n=62). Regarding the histological variables, 18 patients had grade I (11.8%), 112 grade II (73.7%), and 22 grade III (14.5%) classified according to Patnaik et al. (1984). According to the classification of Kiupel et al. (2011) 37 cases were classified as high grade (35.2%) and 68 as low grade (64.8%). Statistical association was observed when the presence of solitary/multiple nodules and the histological grade were evaluated according to Patnaik et al. (1984) (P=0.008) and Kiupel et al. (2011) (P=0.004). The nodules with worse prognostic feature were more frequent in animals diagnosed with multiple nodules, regardless of the histological classification used. The presence of multiple nodules in stage II or IV (p<0.001) and recurrence of the disease (p=0.001) was also observed. Regarding the histological classification of Kiupel et al. (2011), there was a statistical association between histological grade and tumor size (p=0.001), consistency (p=0.028) and nodule growth rate (p<0.001), lymph node enlargement (p<0.001) and the treatment used (p=0.002). Nodules larger than three centimeters (56.8% n=21) and fast growing (52.9% n=36%) were more frequent in high-grade tumors. Lymph node enlargement (80.6% n=25) and chemotherapeutic treatment (83.3% n=5) were also associated with patients with this histological grade. According to the classification of Patnaik et al. (1984), breed and sex differed proportionally between the histological groups (p=0.008 and 0.040 respectively), and lymph node enlargement and rapid tumor growth were also associated with histological grade (p=0.002 and 0.001). Almost half of the patients (47.4%) underwent surgical and chemotherapeutic treatment (n=91) while only surgical procedure was performed in 31.3% (n=60) of the patients. Sixty-one animals (31.8%) had enlarged regional lymph nodes (31.8%), and 71.9% of the nodes evaluated had rapid growth. The clinical evolution time of the tumor was less than or equal to one year in 158 patients (82.3%), followed by 1 to 2 years in 25 patients (13%). There were 66 cases (40.5%) of recurrence and 16 (8.3%) of distant metastasis. With this study, it can be concluded that dogs with mixed breed are the most affected by cutaneous mastocytoma in Jaboticabal city, followed by Boxer dogs, with ages varying between 7 and 11 years, with no sexual predisposition observed. It was also concluded that nodules were predominantly non-ulcerated, solitary and smaller than 3 centimeters, that the majority of patients presented grade II mastocytoma according to Patnaik et al. (1984) and low grade according to Kiupel et al. (2011), not being observed in most of them recurrence, lymph node or distance metastasis. The most commonly used diagnosis was fine-needle aspiration associated with histopathology, and in relation to location, nodules were found predominantly in pelvic and thoracic limbs, followed by head and neck. The consistency of the nodules was both firm and soft, and half of the patients underwent the associated surgical procedure of antineoplastic chemotherapy.(AU)

Histochemical and immunohistochemical evaluation of angiogenesis in rabbits (Oryctolagus cuniculus) submitted to skin grafts associated with platelet-rich plasma / Histoquímica e imunohistoquíca na avaliação da angiogênese em coelhos submetidos ao emprego de enxertos cutâneos associado com plasma rico em plaquetas

Histochemical staining consists of a set of specific chemical reactions of structures or tissue-endogenous substances. Immunohistochemistry allows verification of proteins in tissues related to biological and pathological factors. The standardization of methods to assess angiogenesis resulting from formation of new blood vessels in procedures with stimulants is important to facilitate the implementation of research as well as to assist interpretation of data. In rabbits some markers of angiogenesis antibodies in the skin are not standardized because of cross-reactions that may occur because the antibodies are made from such animals.The aim of this study was to analyze the immunohistochemical methods through dyes and immunohistochemical markers angiogenesis in rabbits (Oryctolagus cuniculus) having undergone reconstructive surgery with skin grafts associated with plasma angiogenesis stimulator rich in platelets, in order to evaluate which method would be better to visualize the vessels, as well as to evaluate which antibody would promote better immunostaining, and find the differences between the methods and to standardize the methodology to be applied in experiments using rabbits. Sixteen rabbits were used, split into two groups of eight animals: Gprp (plasma rich in platelets) and Gc (control, saline solution, 9%). The same technique of reconstructive surgery using graft mesh was performed on each rabbit. The groups differed only in the application of platelet-rich plasma before the surgical wound synthesis. Samples for evaluation of angiogenesis were collected 15 days after the surgical procedure. The dyes Hematoxylin & Eosin and Masson's Trichrome were used in the histochemical study to evaluate vascular proliferation. Markers CD31, CD34 and Caveolin-1 was used for the immunohistochemical study. The evaluation between the groups (Gprp and Gc) in regard to the categorical variable (vascular proliferation intensity) used the Kruskal-Wallis test with p values equal to or less than 0.05 being considered significant. The immunohistochemistry was subjected to analysis of variance for a completely randomized design, with two groups and five repetitions (medium) and 5% significance level. Multiple comparison of groups resulted in the Tukey test (p=0.05) used. The amount of vascular proliferation assessed by histochemical method HE and Masson's Trichrome was found to be a significant variable in Gprp when compared with group Gc. When evaluating the methods used, there was no significant difference. There was no difference in the three markers which were used for correlating microvessels; however, there was more intense staining of vessels when Caveolin-1 Antibody was used. This caused intense marking of the capillaries and small vessels, as well as of larger vessels. When using CD31 and CD34, the same was observed, but it was not as intense as with Caveolin-1; though some cases showed sincere and discreet marking. The results of this study demonstrated that the histochemical methods performed are effective for semi-quantitative assessment of angiogenesis. The immunohistochemical comparison of Caveolin-1, CD31, and CD34 as markers of angiogenesis in rabbits showed that both antibodies could immunostain the newly formed vessels; but the Caveolin-1 showed better immunostaining in small and medium-sized vessels, as well as a minor presence in the background. Although not specific markers for angiogenesis, they can be used as immunohistochemical markers of vascular endothelium in rabbits.(AU)

Colorações histoquímicas consistem de um conjunto de reações químicas específicas das estruturas ou substâncias endógenas do tecido. Logo a Imunohistoquímica permite observar proteínas presentes nos tecidos relacionadas com fatores determinantes do comportamento biológico e patológico. A padronização dos métodos que avaliam a angiogênese decorrente de procedimentos que utilizam substâncias estimulantes à formação de novos vasos são importantes, a fim de facilitar a execução das pesquisas, bem como auxiliar na interpretação dos dados, visto que em coelhos alguns anticorpos marcadores de angiogênese na pele ainda não são padronizadas em virtude das reações cruzadas que podem ocorrer devido aos anticorpos serem confeccionados a partir de tais animais. Objetivou-se analisar os métodos histoquímicos por meio das colorações e imunohistoquímicas com marcadores de angiogênese em coelhos (Oryctolagus cuniculus) submetidos ao emprego de enxertos cutâneos associado com estimulador de angiogênese plasma rico em plaquetas, a fim de avaliar qual método seria melhor para visualização dos vasos, bem como avaliar qual anticorpo promoveria melhor imunomarcação, buscando-se assim encontrar a diferenças entre os métodos e padronizar a metodologia a ser aplicada em experimentos que utilizem coelhos. Utilizou-se 16 coelhos, separados em dois grupos com oito animais, compreendendo os grupos Gprp (plasma rico em plaquetas) e Gc (controle, solução fisiológica 0,9%). Em todos os animais foi realizada a mesma técnica de cirurgia reconstrutiva de enxertia do tipo malha, os grupos diferiram apenas a aplicação do plasma rico em plaquetas antes da síntese da ferida cirúrgica. As amostras para avaliação da angiogênese foram coletadas após 15 dias do procedimento cirúrgico. Utilizou-se no estudo histoquímico as colorações Hematoxilina & Eosina e Tricrômico de Masson para avaliação da proliferação vascular, e os anticorpos CD31 e CD34 e Caveolina - 1 para avaliação imunohistoquímica. A comparação entre os grupos (Gprp e Gc) em relação à variável categórica (intensidade de proliferação vascular) foi utilizado o teste de Kruskal-Wallis, com valores de p iguais ou inferiores a 0,05 foram considerados significativos. Os dados imuno-histoquímico foram submetidos à análise de variância para um delineamento inteiramente ao acaso, com 2 grupos e 5 repetições (médias) e nível de significância de 5%. Nas comparações múltiplas das médias dos grupos, utilizou-se o teste de Tukey (α = 0,05). A intensidade de proliferação vascular avaliada pelo método histoquímico HE e Tricômico de Masson encontrou-se que tal variável foi significativa no Gprp, quando comparado com o Gc. Avaliando os métodos utilizados não houve diferença significativa. A contagem microvascular (MVC) realizada com os diferentes marcadores (Caveolina-1, CD31 e CD34) foi significativa no Gprp. Correlacionando a contagem microvascular dos três marcadores utilizados não houve diferença significativa, no entanto observou-se marcação mais intensa dos vasos utilizando o anticorpo Caveolina-1, sendo intensa a marcação dos capilares, vasos de pequeno calibre, bem como em vasos maiores. Nas avaliações de CD31 e CD34 observou que houve imunomarcação dos vasos, porém não foi intensa como a Caveolina-1, alguns casos apresentaram fundo, bem como marcação discreta. Os resultados encontrados neste estudo evidenciaram os métodos histoquímicos são eficazes para avaliação semiquantitativa da angiogênese. A comparação imunohistoquímicas da Caveolina-1, CD31 e CD34 como marcadores de angiogênese em coelhos evidenciaram que ambos os anticorpos são capazes de imunomarcar os vasos neoformados, porém a Caveolina-1 apresentou melhor imunomarcação de vasos de pequeno e médio calibre, bem como menor presença de fundo, embora não seja um marcador específico para angiogênese pode ser utilizada como marcador imunohistoquímico de endotélio vascular em coelhos.(AU)

Comparação de duas classificações histopatológicas com o padrão de imuno-marcação para KIT, a avaliação da proliferação celular e com a presença de mutações no c-KIT de mastocitomas cutâneos caninos / Comparison of two histopathological classifications with pattern of immunostaining KIT, evaluation of cell proliferation and the presence of mutations in c-KIT canine cutaneous mast cell tumors

A graduação histopatológica é o método de eleição para prever o comportamento biológico do mastocitoma e, atualmente, são utilizados os métodos de Patnaik e de Kiupel para dividi-los em graus de malignidade. O objetivo do presente trabalho foi comparar as duas classificações histológicas com as variáveis clínicas, os marcadores imuno-histoquímicos e com a presença de mutações para verificar as características que estão mais relacionadas entre si e com os piores prognósticos. Foram avaliados 61 animais, levando em consideração o sexo, a raça, a idade, a localização tumoral, o grau tumoral pelas classificações de Patnaik e Kiupel, a infiltração de eosinófilos, a marcação do KIT e do Ki-67 e a presença de mutação. As variáveis foram correlacionadas utilizando os testes de qui-quadrado, teste de Fisher, teste de verossimilhança e o teste de risco relativo. Os animais idosos foram os mais acometidos, enquanto os animais sem raça definida e os das raças Boxer, Labrador e Pinscher foram aqueles com maior predisposição ao desenvolvimento tumoral. A localização e a idade estão associadas ao grau tumoral. Os tumores em cabeça, pescoço e região genital têm 10 vezes mais chance de serem classificados como de alto grau (RR=10,667; IC95% 1,909-59,615, p=0,004) e os idosos oito vezes mais chance (RR=8,00; IC95% 0,955-67,009; p=0,029). Os tumores de grau II e os de baixo grau foram os mais encontrados e as duas classificações histológicas demonstram correlação muito significativa entre si (p<0,001). A concentração do infiltrado eosinofílico não demonstrou correlação significativa com nenhuma das classificações histológicas. O padrão KIT foi dependente da localização tumoral (p=0,015), já que os tumores genitais, na cabeça e no pescoço possuíam 18 vezes mais chance de apresentarem padrão citoplasmático (RR=18,571; IC95% 1,954-176,490; p=0,003), e das classificações de Patnaik (p=0,001) e Kiupel (p<0,001), sendo que os tumores de alto grau têm 36 vezes mais chance de apresentarem padrão citoplasmático (RR=36,00, IC95% 4,35-297,948; p<0,001). A marcação do Ki-67 demonstrou dependência da localização (p=0,024). A presença de mutação no exon 11 do domínio justamembrana não demonstrou associação com nenhuma das variáveis clínicas, das classificações histológicas, da concentração de eosinófilos e do padrão KIT. A presença da mutação foi correlacionada significativamente apenas ao Ki-67 (p=0,010). Os resultados obtidos sugerem que a localização é a variável clínica mais relacionada ao prognóstico e que apenas a classificação de Kiupel associada à imuno-histoquímica são eficientes para avaliar o comportamento tumoral.(AU)

Histopathological classification is the method of choice to predict the biological behavior of mast cell tumor. Currently, the methods of Patnaik and Kiupel are used to divide them into degrees of malignancy. The objective of this study was to compare the two histological grades with clinical, immunohistochemical markers and the presence of mutations to evaluate the characteristics that are more related to each other and with the worst prognosis. Sixty-one dogs were evaluated, taking into account sex, race, age, tumor location, tumor grade by grades Patnaik and Kiupel, infiltration of eosinophils, pattern KIT, Ki-67 and the presence of mutation . The variables were correlated using the chi-square test, Fisher's exact test, verisimilitude test and relative risk test. The older dogas were the most affected, while animals mixed breed, Boxer breeds, Labrador and Pinscher were those with greater predisposition to tumor development. The tumor location and age are associated with tumor grade. The tumors in the head, neck and genital area are 10 times more likely to be classified as high-grade (RR=10,667; 95% CI 1.909 to 59.615, p=0.004) grau and old-aged eight times more likely (RR=8.00, 95% CI 0.955 to 67.009, p=0.029). The grade II tumors and the low degree were the most frequent and the two histological scores showed very significant correlation (p<0.001). The concentration of eosinophilic infiltration showed no significant correlation with any of the histological scores. The standard KIT was dependent on tumor location (p=0.015), genital tumors, head and neck had 18 times more likely to have cytoplasmic pattern (RR=18.571, 95% CI 1.954 to 176.490, p=0.003), and Patnaik (p=0.001) and Kiupel (p<0.001) ratings. The high grade tumors are 36 times more likely to have cytoplasmic pattern (RR 36.00, 95% CI 4.35-297.948 p<0.001). The marking of the Ki-67 showed a dependence on the location (p=0.024). The presence of mutation in exon 11 of the juxtamembrane domain showed no association with any of the clinical variables of the histological scores, the concentration of eosinophils and KIT standard. The presence of the mutation was significantly correlated only to the Ki-67 (p=0, 010). The results suggest that the location is the clinical variable most related to prognosis and that only Kiupel classification associated with immunohistochemistry are efficient to assess tumor behavior.(AU)

Mitochondrial genetic diversity, selection and recombination in a canine transmissible cancer.

Canine transmissible venereal tumour (CTVT) is a clonally transmissible cancer that originated approximately 11,000 years ago and affects dogs worldwide. Despite the clonal origin of the CTVT nuclear genome, CTVT mitochondrial genomes (mtDNAs) have been acquired by periodic capture from transient hosts. We sequenced 449 complete mtDNAs from a global population of CTVTs, and show that mtDNA horizontal transfer has occurred at least five times, delineating five tumour clades whose distributions track two millennia of dog global migration. Negative selection has operated to prevent accumulation of deleterious mutations in captured mtDNA, and recombination has caused occasional mtDNA re-assortment. These findings implicate functional mtDNA as a driver of CTVT global metastatic spread, further highlighting the important role of mtDNA in cancer evolution.

Utilização de plasma rico em plaquetas para estimulação da angiogênese em flape de padrão axial toracodorsal em coelhos (Oryctolagus cuniculus) / Use of platelet rich plasma to stimulate angiogenesis in the thoracodorsal axial pattern flap in rabbits (Oryctolagus cuniculus)

Feridas de grandes extensões, com perda da viabilidade tecidual e retardo na cicatrização por segunda intenção são casos que se faz necessário o emprego de técnicas cirúrgicas reconstrutivas. O plasma rico em plaquetas (PRP) é um produto com maior concentração plaquetária, adjuvante no processo cicatricial de cirurgias reconstrutivas, auxiliando nos processos de hemostasia e estimulação da angiogênese. Dessa forma, delineou-se um estudo a fim de avaliar a eficácia do uso do gel produzido a partir do plasma rico em plaquetas (PRP) em flapes de avanço de padrão axial toracodorsal em coelhos, para avaliar a possibilidade de favorecer a integração do retalho no leito receptor. Utilizaram-se 30 coelhos da raça Nova Zelândia branco, separados em dois grupos de 15 animais, compreendendo os grupos plasma rico em plaquetas (GPRP), na qual empregou-se o gel antes da síntese da ferida cirúrgica, e controle (GC), na qual utilizou-se apenas solução fisiológica. Para obtenção do PRP, coletou-se sangue dos animais, e determinou-se a contagem plaquetária antes da preparação do gel. No início e término do experimento os animais foram pesados para posterior análise de ganho peso médio. Após o procedimento cirúrgico iniciou-se as avaliações macroscópicas no 3º, 7º e 14º dia, e avaliou-se presença ou ausência de exsudato, integridade da pele, edema, rubor e necrose. Após esta etapa, coletou-se o material da ferida cirúrgica para confecção das lâminas histológicas e posterior avaliação microscópica. Avaliou-se a proliferação vascular, presença de células mononucleares e polimorfonucleares, proliferação fibroblástica, colagenização, reepitelização e hemorragia. Os dados obtidos foram submetidos à análise estatística (Teste t Student, t emparalhado, e Kruskall Walis, sendo p<0,05)[...]

Wounds of large tracts with loss of tissue viability and delayed healing by secondary intention are cases where it is necessary the use of reconstructive surgical techniques. The platelet rich plasma (PRP) is a product with a higher platelet concentration, adjuvant in the healing process of reconstructive surgeries, assisting in the processes of hemostasis and stimulation of angiogenesis. Thus, a study was devised to assess the efficacy of the gel produced from the platelet rich plasma (PRP) in the forward axial flaps thoracodorsal pattern in rabbits to evaluate the ability to promote the integration of the flap the recipient bed. We used 30 white rabbits New Zealand, separated into two groups of 15 animals, comprising the platelet rich plasma groups (GPRP), in which we used the gel before the synthesis of the surgical wound , and control (CG), in which only saline was used. To obtain the PRP, the blood was collected from the animals, was determined and the platelet count before preparation of the gel. At the beginning and end of the experiment the animals were weighed for analysis of average weight gain. After surgery began macroscopic in the 3rd, 7th and 14th day reviews, and we assessed the presence or absence of exudate, skin integrity, edema, redness and necrosis. After this step, yielded the material for the manufacture of surgical wound, followed by microscopic histological slides. We evaluated vascular proliferation, presence of polymorphonuclear and mononuclear cells, fibroblast proliferation, collagen deposition, reepithelialization and hemorrhage. The data were subjected to statistical analysis (Student t test, t paired, and Kruskal Wallis test, and p<0.05)[...]

Method to obtain platelet-rich plasma from rabbits (Oryctolagus cuniculus ) / Método de obtenção de plasma rico em plaquetas de coelhos (Oryctolagus cuniculus)

Platelet-rich plasma (PRP) is a product easy and inxpesnsive, and stands out to for its growth factors in tissue repair. To obtain PRP, centrifugation of whole blood is made with specific time and gravitational forces. Thus, the present work aimed to study a method of double centrifugation to obtain PRP in order to evaluate the effective increase of platelet concentration in the final product, the preparation of PRP gel, and to optimize preparation time of the final sample. Fifteen female White New Zealand rabbits underwent blood sampling for the preparation of PRP. Samples were separated in two sterile tubes containing sodium citrate. Tubes were submitted to the double centrifugation protocol, with lid closed and 1600 revolutions per minute (rpm) for 10 minutes, resulting in the separation of red blood cells, plasma with platelets and leucocytes. After were opened and plasma was pipetted and transferred into another sterile tube. Plasma was centrifuged again at 2000rpm for 10 minutes; as a result it was split into two parts: on the top, consisting of platelet-poor plasma (PPP) and at the bottom of the platelet button. Part of the PPP was discarded so that only 1ml remained in the tube along with the platelet button. This material was gently agitated to promote platelets resuspension and activated when added 0.3ml of calcium gluconate, resulting in PRP gel. Double centrifugation protocol was able to make platelet concentration 3 times higher in relation to the initial blood sample. The volume of calcium gluconate used for platelet activation was 0.3ml, and was sufficient to coagulate the sample. Coagulation time ranged from 8 to 20 minutes, with an average of 17.6 minutes. Therefore, time of blood centrifugation until to obtain PRP gel took only 40 minutes...

O plasma rico em plaquetas (PRP) é um produto de fácil obtenção a baixo custo, destacando-se pelos seus fatores de crescimento na reparação tecidual. Para obtenção do PRP, a centrifugação do sangue total é realizada com tempos e forças gravitacionais específicas. Assim, o presente trabalho teve por objetivo estudar o método da dupla centrifugação para obtenção do PRP, a fim de avaliar a eficácia de aumento da concentração de plaquetas no produto final, a preparação de gel de PRP e otimizar o tempo de preparação da amostra final. Quinze coelhos Nova Zelândia Branco, fêmeas, foram submetidos à coleta de sangue para a preparação de PRP. As amostras foram separadas em dois tubos estéreis contendo citrato de sódio. Os tubos foram submetidos ao protoloco de dupla centrifugação, com a tampa fechada a 1600 revoluções por minuto (rpm) durante 10 minutos, resultando na separação dos glóbulos vermelhos, plaquetas e plasma contendo os leucócitos. Na sequência, foram destapados para pipetar o plasma e transferí-lo para outro tubo de estéril. O plasma foi novamente centrifugado a 2000pm durante 10 minutos, resultando em duas partes: a parte superior, que consistia em plasma pobre em plaquetas (PPP) e a parte inferior do botão de plaquetas. Parte PPP foi descartado de modo que apenas 1ml de PPP permaneceu no frasco juntamente com o botão de plaquetas. Este material foi agitado suavemente para promover a ressuspensão das plaquetas, o que resultou na produção de PRP. O protocolo de centrifugação dupla foi capaz de promover a concentração de plaquetas 3 vezes maior em relação à amostra de sangue inicial. O volume de gluconato de cálcio utilizado para a ativação das plaquetas foi de 0,3ml, e foi suficiente para coagular a amostra, e o tempo de coagulação variou de 8 a 20 minutos, com uma média de 17,6 minutos. O tempo da centrifugação do sangue até a obtenção do PRP gel levou apenas 40 minutos...

Paraneoplastic neutrophilic leukocytosis syndrome in a cat with recurrent mammary carcinoma.

CASE SUMMARY: A spayed 12-year-old female domestic shorthair cat presented with nodular lesions on the ventral-right thoracic wall after complete mastectomy 4 months previously. The prior diagnosis was tubulopapillary mammary carcinoma with axillary lymph node metastasis, and a recurrence was confirmed. A gradual and sequential increase in the total number of leukocytes with severe neutrophilia (95.632/µl) developed over the course of the illness, along with an increase in the size of the recurrent mass. The severe leukocytosis did not show any response to antibiotic therapy, and no evidence of infection was observed. Bone marrow cytology confirmed hypercellularity in the myeloid cell lineage. Based on these findings, paraneoplastic neutrophilic leukocytosis syndrome was suspected. An incisional biopsy of the recurrent mass was consistent with recurrent tubulopapillary mammary carcinoma. Malignant epithelial cells stained positive upon immunohistochemistry for granulocyte-macrophage colony-stimulating factor, cytokeratin and vimentin. After the final diagnosis of paraneoplastic neutrophilic leukocytosis syndrome, the cat was euthanized at the owner's request. RELEVANCE AND NOVEL INFORMATION: This is a novel case of paraneoplastic leukocytosis syndrome associated with mammary carcinoma in a cat. Although there are some reports describing paraneoplastic leukocytosis in cats, the relationship between this syndrome and feline mammary tumors has not been described.

Aspecto radiológico e macroscópico de matriz óssea mineralizada heteróloga fragmentada e polimetilmetacrilato autoclavados em falha óssea de tíbia de coelho / Radiological and macroscopic aspects of autoclaved heterologous fragmented mineralized bone matrix and polymethylmethacrylate in bone defect in tibia of rabbits

Foi realizada falha segmentar com 6mm de diâmetro na região metafisária medial de tíbias de 12 coelhos, onde foi implantado uma associação de micro e macrofragmentos de matriz óssea cortical heteróloga fragmentada conservada em glicerina (98%) e polimetilmetacrilato autoclavados, para a sua reconstrução, e avaliados radiológica e macroscopicamente aos 30, 60, 90 e 120 dias. Houve adesão, em relação ao tempo, dos micro e macrocompósitos ao leito receptor, em 100% dos casos, mostrando ser biologicamente biocompatível, pois promoveram a reparação de falhas ósseas, sem sinais de infecção, migração e/ou rejeição, podendo, dessa forma, ser mais uma opção como substituto para preencher grandes defeitos ósseos.

A segmental defect of 6mm diameter was performed in the medial metaphyseal region of the tibia of 12 rabbits. For the bone defect reconstruction there was implanted a combination of micro and macro fragments of heterologous fragmented cortical bone matrix preserved in glycerin (98%) and polymethylmethacrylate, both autoclaved. Radiological and macroscopic evaluation was performed at 30, 60, 90 and 120 days. Adhesion in relation to time of the micro and macro composites to the recipient bed was observed in 100% of the cases. This showed that this implant is biologically biocompatible, since it promoted bone defects repair, with no signs of infection, migration and/or rejection. In this way, this implant can be classified as one more option of substitute to fill large bone defects.

Effects of isoflurane on echocardiographic parameters in healthy dogs.

OBJECTIVE: To study the echocardiographic effects of isoflurane at an end-tidal concentration approximating 1.0 times the minimum alveolar concentration (MAC) in healthy unpremedicated dogs. STUDY DESIGN: Prospective experimental trial. ANIMALS: Sixteen mature mongrel dogs of either sex weighing 11.06 +/- 2.72 kg. METHODS: After performing a baseline echocardiogram in the awake animal, anesthesia was induced with increasing inspired concentrations of isoflurane via a face mask until tracheal intubation was possible. Following intubation, the end-tidal concentration was decreased to 1.4% for the rest of the anesthetic period. Serial echocardiograms were recorded at 25, 40, and 55 minutes after the end-tidal concentration was reached. RESULTS: No changes were observed in heart rate. However, significant decreases were seen in left ventricular end-diastolic diameter (Mean maximal change: 13.8%), interventricular septal thickness during systole (15.2%), interventricular septal thickening fraction (72.2%), left ventricular free wall thickening fraction (63.5%), ejection fraction (39.9%), and fractional shortening (46.7%). In addition, peak flow velocities across mitral, pulmonic, and aortic valves were significantly lower than baseline values. Decreases were also observed in end-diastolic left ventricular volume index (approximately 32.1% from the awake value), stroke index (58.2%), and cardiac index (55.3%) when compared with awake measurements. CONCLUSIONS: and clinical relevance Our results indicate that 1 x MAC isoflurane caused significant myocardial depression in healthy dogs. These changes in myocardial function need to be considered carefully when isoflurane is to be used in dogs with poor cardiovascular reserve.