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La leptospirose est une zoonose à distribution mondiale dont la prévalence chez le chat varie géographiquement de 4.8% à 35%. Bien que l’exposition féline à Leptospira spp. soit rapportée dans des études sérologiques, les conséquences cliniques de cette maladie chez le chat sont peu connues. Le but principal de cette étude était de comparer le statut sérologique et de porteur (PCR urinaire) de Leptospira spp. entre des chats sains et des chats atteints de maladie rénale (insulte rénale aigue et maladie rénale chronique de stades IIb, III et IV). Une étude préliminaire pour valider la sensibilité et la spécificité analytiques de la PCR de Leptospira spp. réalisée par le Laboratoire de Diagnostic Moléculaire de la FMV sur l’urine de chat a été effectuée. La validation in vitro a démontré que la technique de PCR est efficace pour déterminer la présence de leptospires pathogènes dans l’urine du chat. Dans le cadre de l’étude principale, 251 chats ont été recrutés entre janvier 2010 et mars 2012,. De ceux-ci, 240 ont été inclus et divisés en 2 groupes (chats sains (C=125) et chats atteints de maladie rénale (MR=115) en se basant sur un examen physique ainsi que sur des résultats d’hématologie, de biochimie et d’analyse d’urine. Tous les chats recrutés ont également été examinés sérologiquement par test de micro-agglutination pour la présence d’anticorps contre Leptospira spp. (résultat considéré positif si ≥1 :100) et par PCR pour la présence de Leptospira spp. dans l’urine. Le pourcentage prédit de séropositivité pour Leptospira spp. était significativement plus élevé chez les chats atteints de maladie rénale (13,7%) que chez les chats sains (5%) (p=0,02). Les sérovars impliqués étaient Pomona (n=16), Bratislava (n=8) et Grippotyphosa (n=1). De plus, les chats séropositifs pour Pomona présentaient des titres significativement plus élevés que pour les autres sérovars (p=0,04). L’excrétion de Leptospira spp. a été confirmée par PCR dans l’urine de huit chats. Des 26 chats séropositifs, quatre (C=2, MR=2) se sont également révélés PCR positifs. La prévalence a été plus élevée chez les chats du groupe MR (5.3%; 6/113) lorsque comparée à celle du groupe C (1.6%; 2/125), mais cette différence ne s’est pas révélée statistiquement significative (C=0,9% , MR= 5,5% ; p = 0,09). L’âge, le sexe et le milieu de vie (urbain versus rural) n’ont pas influencé le statut sérologique ou d’excrétion pour Leptospira spp. Le pourcentage prédit de séropositivité était significativement plus élevée chez les chasseurs (p<0.01) et pendant les mois de juin à août (p=0.02). La présence d’un autre chat à la maison a également significativement augmenté ce pourcentage (p<0.01), mais la présence d’un chien ne l’a pas influencé. Lors de l’évaluation du PCR par le modèle GGE, seules les variables « contact avec raton laveur » et « contact avec mouffettes » sont ressorties statistiquement significatives (p≤0.03). Le rôle que joue Leptospira spp. comme agent étiologique de maladie rénale chez le chat demeure incertain. Toutefois, la différence significative de statut sérologique entre les chats sains et les chats atteints de maladie rénale suggère que la leptospirose pourrait être une cause sous-diagnostiquée de maladie rénale chez cette espèce. Dans cette étude, plusieurs porteurs asymptomatiques ont été identifiés, ce qui suggère que l’espèce féline puisse être un acteur sous-estimé dans la transmission de la bactérie aux humains. / Leptospirosis is a globally widespread zoonosis, with prevalence in cats varying from 8.8% to 35% depending on geographical localization. Although serologic evidence of feline exposure exists, clinical disease is rarely reported. This study aimed to compare seropositivity and urinary PCR status for Leptospira spp. between healthy cats (H) and cats with kidney disease (KD: acute kidney injury (AKI) and chronic KD stages IIb, III and IV). The analytical sensitivity and specificity of the PCR performed by the Laboratoire de Diagnostic Moléculaire of the FMV were evaluated. In vitro validation showed that the PCR technique is effective for determining the presence of pathogenic leptospires in the urine of cats. A total of 251 cats were recruited, from which 240 cats were enrolled. Cats were enrolled from January 2010 to March 2012 and divided into two groups, H (n=125) and KD (n=115), based on complete blood count, serum biochemistry profile and urinalysis. Leptospira spp. serology by microscopic agglutination test (titers ≥ 1:100 considered positive) and urinary PCR were performed in all cats. Predicted seropositivity for Leptospira spp. was statistically different between groups; being 5% and 13,7% in the H and KD groups respectively (p=0.02). Serovars involved were Pomona (n=16), Bratislava (n=8) and Grippotyphosa (n=1), with titers being significantly higher for Pomona (p=0.04). The excretory status was confirmed by a positive urine PCR in eight cats. Of the 26 seropositive cats, four (H=2, KD=2) were also PCR positive. The prevalence of PCR positive cats was higher in the KD group (5.3%; 6/113) compared with the H group (1.6%; 2/125), but the difference between groups did not reach statistical significance (0.9% in H, 5.5% in KD; p=0.09). Age, sex and rural versus urban environment did not influence serologic or PCR status for Leptospira spp. Predicted seropositivity was greater between June and August (p =0.02) and in known hunters (p<0.01). The presence of another cat at home also increased significantly the predicted seropositivity (p<0.01), although the presence of a dog did not. When evaluating the PCR status of cats in the GEE model for individually tested variables, only the variables “contact with raccoons” and “contact with skunks” were statistically significant (P ≤ .03). Although the precise role of Leptospira spp. as an etiologic agent of feline KD remains unclear, the significant difference in the serologic status found between H and KD cats suggests that it may be an under-diagnosed cause of KD in cats. Several asymptomatic carriers were identified, suggesting that cats could be underestimated players in the transmission of the bacteria to humans.

La leptospirose est une zoonose à distribution mondiale dont la prévalence chez le chat varie géographiquement de 4.8% à 35%. Bien que l’exposition féline à Leptospira spp. soit rapportée dans des études sérologiques, les conséquences cliniques de cette maladie chez le chat sont peu connues. Le but principal de cette étude était de comparer le statut sérologique et de porteur (PCR urinaire) de Leptospira spp. entre des chats sains et des chats atteints de maladie rénale (insulte rénale aigue et maladie rénale chronique de stades IIb, III et IV). Une étude préliminaire pour valider la sensibilité et la spécificité analytiques de la PCR de Leptospira spp. réalisée par le Laboratoire de Diagnostic Moléculaire de la FMV sur l’urine de chat a été effectuée. La validation in vitro a démontré que la technique de PCR est efficace pour déterminer la présence de leptospires pathogènes dans l’urine du chat. Dans le cadre de l’étude principale, 251 chats ont été recrutés entre janvier 2010 et mars 2012,. De ceux-ci, 240 ont été inclus et divisés en 2 groupes (chats sains (C=125) et chats atteints de maladie rénale (MR=115) en se basant sur un examen physique ainsi que sur des résultats d’hématologie, de biochimie et d’analyse d’urine. Tous les chats recrutés ont également été examinés sérologiquement par test de micro-agglutination pour la présence d’anticorps contre Leptospira spp. (résultat considéré positif si ≥1 :100) et par PCR pour la présence de Leptospira spp. dans l’urine. Le pourcentage prédit de séropositivité pour Leptospira spp. était significativement plus élevé chez les chats atteints de maladie rénale (13,7%) que chez les chats sains (5%) (p=0,02). Les sérovars impliqués étaient Pomona (n=16), Bratislava (n=8) et Grippotyphosa (n=1). De plus, les chats séropositifs pour Pomona présentaient des titres significativement plus élevés que pour les autres sérovars (p=0,04). L’excrétion de Leptospira spp. a été confirmée par PCR dans l’urine de huit chats. Des 26 chats séropositifs, quatre (C=2, MR=2) se sont également révélés PCR positifs. La prévalence a été plus élevée chez les chats du groupe MR (5.3%; 6/113) lorsque comparée à celle du groupe C (1.6%; 2/125), mais cette différence ne s’est pas révélée statistiquement significative (C=0,9% , MR= 5,5% ; p = 0,09). L’âge, le sexe et le milieu de vie (urbain versus rural) n’ont pas influencé le statut sérologique ou d’excrétion pour Leptospira spp. Le pourcentage prédit de séropositivité était significativement plus élevée chez les chasseurs (p<0.01) et pendant les mois de juin à août (p=0.02). La présence d’un autre chat à la maison a également significativement augmenté ce pourcentage (p<0.01), mais la présence d’un chien ne l’a pas influencé. Lors de l’évaluation du PCR par le modèle GGE, seules les variables « contact avec raton laveur » et « contact avec mouffettes » sont ressorties statistiquement significatives (p≤0.03). Le rôle que joue Leptospira spp. comme agent étiologique de maladie rénale chez le chat demeure incertain. Toutefois, la différence significative de statut sérologique entre les chats sains et les chats atteints de maladie rénale suggère que la leptospirose pourrait être une cause sous-diagnostiquée de maladie rénale chez cette espèce. Dans cette étude, plusieurs porteurs asymptomatiques ont été identifiés, ce qui suggère que l’espèce féline puisse être un acteur sous-estimé dans la transmission de la bactérie aux humains. / Leptospirosis is a globally widespread zoonosis, with prevalence in cats varying from 8.8% to 35% depending on geographical localization. Although serologic evidence of feline exposure exists, clinical disease is rarely reported. This study aimed to compare seropositivity and urinary PCR status for Leptospira spp. between healthy cats (H) and cats with kidney disease (KD: acute kidney injury (AKI) and chronic KD stages IIb, III and IV). The analytical sensitivity and specificity of the PCR performed by the Laboratoire de Diagnostic Moléculaire of the FMV were evaluated. In vitro validation showed that the PCR technique is effective for determining the presence of pathogenic leptospires in the urine of cats. A total of 251 cats were recruited, from which 240 cats were enrolled. Cats were enrolled from January 2010 to March 2012 and divided into two groups, H (n=125) and KD (n=115), based on complete blood count, serum biochemistry profile and urinalysis. Leptospira spp. serology by microscopic agglutination test (titers ≥ 1:100 considered positive) and urinary PCR were performed in all cats. Predicted seropositivity for Leptospira spp. was statistically different between groups; being 5% and 13,7% in the H and KD groups respectively (p=0.02). Serovars involved were Pomona (n=16), Bratislava (n=8) and Grippotyphosa (n=1), with titers being significantly higher for Pomona (p=0.04). The excretory status was confirmed by a positive urine PCR in eight cats. Of the 26 seropositive cats, four (H=2, KD=2) were also PCR positive. The prevalence of PCR positive cats was higher in the KD group (5.3%; 6/113) compared with the H group (1.6%; 2/125), but the difference between groups did not reach statistical significance (0.9% in H, 5.5% in KD; p=0.09). Age, sex and rural versus urban environment did not influence serologic or PCR status for Leptospira spp. Predicted seropositivity was greater between June and August (p =0.02) and in known hunters (p<0.01). The presence of another cat at home also increased significantly the predicted seropositivity (p<0.01), although the presence of a dog did not. When evaluating the PCR status of cats in the GEE model for individually tested variables, only the variables “contact with raccoons” and “contact with skunks” were statistically significant (P ≤ .03). Although the precise role of Leptospira spp. as an etiologic agent of feline KD remains unclear, the significant difference in the serologic status found between H and KD cats suggests that it may be an under-diagnosed cause of KD in cats. Several asymptomatic carriers were identified, suggesting that cats could be underestimated players in the transmission of the bacteria to humans.

Spermatogonial stem cells (SSC) self-renew and differentiate into spermatozoa throughout the life of the male. SSC transplantation is a potential method for the propagation of genetically important males. These cells have been isolated in different mammalian species using specific cell surface markers, but not in felines. The goal of this study was to explore a relevant strategy for conservation of endangered felids by characterizing domestic cat (Felis catus) SSCs and assessing their ability for self-renewal after transplantation. Firstly, SSC and pluripotent surface markers, identified in non-feline species, were tested for expression in mixed germ cells from adults by immunocytochemistry and flow cytometry, with immunohistochemical confirmation of expression in prepubertal and adult testis tissue. Secondly, subpopulations were purified through fluorescence-activated cell sorting using spermatogonia-specific markers and molecularly characterized to ascertain levels of pluripotent transcription factors expressed in cat embryos. Thirdly, subpopulations of mixed germ cells and purified spermatogonial cells were transplanted to prepubertal cats to determine: 1) if SSCs capable of colonization were present, and 2) the value of using adolescent domestic cats without depletion of endogenous germ cells as recipients. Fourthly, various culture conditions were evaluated to identify proteins and factors required to maintain proliferation of cat SSCs. Lastly, adult lion testis tissue was characterized with the same surface markers, and mixed germ cells were transplanted to cat testes to evaluate the cat as a suitable host for lion SSC colonization and differentiation. Pluripotent surface markers were more reliable than the common SSC surface markers for isolating cat SSCs. Varying expression levels of pluripotent transcription factors between the different purified cell populations identified spermatogonial subpopulations. Cell purification was not necessary to colonize recipient testes, and transplantation validated the use of prepubertal males as recipients without depletion of endogenous cells. Unlike spermatogonia within mixed germ cells, purified spermatogonia were not maintained under various culture conditions; therefore, SSC culture conditions must be optimized. Similarities in the expression patterns of surface markers in lion and cat spermatogonia were revealed, and colonization of lion SSCs in cat testes provided further evidence of the domestic cat’s relevance as a model for exotic felid SSC transplantation.

Les différents génotypes de Coronavirus canins (CCoV-I/II) et félins (FCoV-I/II) sont phylogénétiquement proches, suggérant des transmissions inter-espèces entre chiens et chats. Lors d’analyses de séquences menées sur des chats infectés, des souches félines atypiques ont pu être mises en évidence, contenant un gène S de type FCoV-I, un gène N de type CCoV-I, ainsi que la présence du gène ORF3, spécifique à CCoV-I. Dans ces souches, le gène ORF3 est présent avec une ou deux délétions toujours identiques, conduisant à la synthèse de protéines tronquées gp3-Δ1 et gp3-Δ2. Les délétions de protéines accessoires étant déjà impliquées dans les transmissions inter-espèces, une étude de caractérisation de la protéine gp3 et de ses différentes formes a été menée. Les trois protéines s’oligomérisent de manière covalente et sont retenues dans le réticulum endoplasmique, en absence de signal spécifique de rétention. Les délétions influencent le niveau d’expression des protéines en cellules félines, où seule l’expression de gp3-Δ1 est visible, alors qu’elles conservent toutes une expression optimale en cellules canines. En l’absence de souches de Coronavirus cultivables en laboratoire contenant le gène ORF3, des cellules canines exprimant l’une des protéines gp3 ont été infectées par une souche CCoV-II. Dans ce modèle, les protéines gp3 ne modifient pas le cycle viral. Dans un contexte d’émergence de nouveaux Coronavirus, la compréhension des mécanismes moléculaires de changement d’hôte est cruciale et les Coronavirus félins et canins peuvent représenter un modèle d’étude utile. / The different genotypes of canine (CCoV-I/II) and feline (FCoV-I/II) Coronaviruses share a close phylogenetic relationship, suggesting inter-species transmissions between cats and dogs. Through sequence analyses of cat samples, atypical FCoV strains, harbouring an S gene related to FCoV-I, an N gene close to the CCoV-I cluster and the ORF3 gene, peculiar to CCoV-I, were discovered. This ORF3 gene was systematically truncated in feline samples, displaying either one or two identical deletions, leading to the translation of gp3-Δ1 and gp3-Δ2. As deletions in accessory proteins have already been involved in host-switch, studies of the different variants of gp3 were conducted. Results demonstrate that all proteins oligomerize through covalent bonds and are retained in the ER, without any specific retention signal. Deletions influence the expression level with a proper expression of the three proteins in canine cells, whereas only gp3-Δ1 expression is sustained in feline cells. As no isolates of Coronavirus harbouring the ORF3 gene exists, cells expressing the different gp3 proteins have been infected with a CCoV-II strain. In this model, the gp3 proteins do not influence the viral life cycle. In the light of emergence of new Coronaviruses, investigations on their molecular mechanisms during the host-switch are crucial and canine and feline Coronaviruses could represent a useful model.

Foram identificadas diversas ambigüidades e contradições acerca do significado semântico, e da identificação de imagens tidas como de \"felinos\", no trabalho de diversos pesquisadores da área andina. Essas contradições são constantemente acompanhadas por uma idéia de que as representações de felinos teriam um conjunto de significados comuns, presentes praticamente em todas as culturas pré-colombianas, desde o período pré-formativo. Este trabalho procura questionar essa idéia, demonstrando, através da sociedade mochica, que as representações de felinos que figuram em suas manifestações artístico-religiosas não correspondem a esta idéia de universalidade. Da mesma forma, são discutidas as contradições presentes na bibliografia, a fim de elucidar a condição do felino dentro do âmbito da cultura analisada. Será dada especial atenção ao fato de que, de forma geral, há uma identificação imediata de imagens de \"mamíferos com presas à mostra\", como sendo de felinos. / Several ambiguities and contradictions in relation to the meaning and the identification of images held as \"felines\" have been identified in the works of many researches specialized in the Andean Pre-Columbian cultures. Such contradictions are constantly followed by the concept that all feline representations would carry the same symbolic meanings, regardless of the cultural differences or of the context in which they would be inserted in. This present work challenges this idea by demonstrating, through the analysis of the iconography produced by the mochica culture, that its feline representations do not correspond to such generalizations. An attempt is also made to elucidate the condition of the image of the feline in realm of the culture here analyzed. Special attention will be given to the fact that usually images of other mammals that carry the symbol of the \"cross-fangs\" are mistakenly identified as felines.

Made available in DSpace on 2016-04-28T20:17:29Z (GMT). No. of bitstreams: 1 2009 - Nadia Rossi de Almeida.pdf: 1219567 bytes, checksum: 83793b5f3d79ab19c2fe40b41ba26f70 (MD5) Previous issue date: 2009-02-05 / The present study had the aim to make a survey of the Feline Leukemia Virus infection in domestic cats of Rio de Janeiro city and Baixada Fluminense region and to analyze risk factors involved in this infection. For this purpose, peripheral blood smears of 1094 cats had been submitted to indirect immunofluorescence for viral antigen detection and data relative to the animals surveyed, such as sex, age, race, access to the street, sexual life, housing, number of contactants and symptoms and/or clinical signals had been registered in individual files. Among the analyzed samples, 11,52% were positive for the test, corresponding to 11,49% of the animals collected at the Rio de Janeiro city and 11,62% of the collected samples at Baixada Fluminense region. The qui-square test was used for the descriptive analysis of all the selected variables, where only the significant variable had been included in multivariate analysis, by logistic regression. In accordance to these analysis, the access to the street, the age range between 1 and 5 years old and the cohabitation with too much cats in groups among 6 to15 cats and above of 15 cats had been considered risk factors for FeLV infection. / O presente estudo teve como objetivo pesquisar a ocorr?ncia da infec??o pelo V?rus da Leucemia Felina (FeLV) em gatos dom?sticos do munic?pio do Rio de Janeiro e Baixada Fluminense e tamb?m analisar fatores de risco envolvidos na infec??o por este retrov?rus. Para esta finalidade, esfrega?os de sangue perif?rico de 1.094 gatos foram submetidos ao teste de imunofluoresc?ncia indireta para pesquisa de ant?geno viral e os dados relativos aos animais, tais como o sexo, idade, ra?a, acesso ? rua, vida sexual, moradia, n?mero de contactantes e sintomas e/ou sinais cl?nicos foram registrados em fichas individuais. Do total de amostras analisadas, 11,52% apresentaram positividade para o teste, correspondendo a 11,49% de ocorr?ncia da infec??o em animais do munic?pio do Rio de Janeiro e 11,62% da Baixada Fluminense. O teste de qui-quadrado foi utilizado para a an?lise descritiva de todas as vari?veis levantadas, onde apenas as vari?veis que apresentaram signific?ncia foram inclu?das na an?lise multivariada, atrav?s da regress?o log?stica. De acordo com estas an?lises, o acesso ? rua, a faixa et?ria entre 1 e 5 anos de idade e a conviv?ncia com demais gatos na faixa entre 6 e 15 gatos e acima de 15 gatos foram fatores de risco para a infec??o pelo FeLV.

O vírus da imunodeficiência felina (FIV) é um lentivirus que infecta gatos domésticos (Felis catus), causando uma imunodeficiência progressiva análoga a AIDS (Síndrome da Imunodeficiência Adquirida Humana). A ampla heterogeneidade molecular do FIV e a alta capacidade de promover mutações sob pressões imunológicas, farmacológicas ou ambientais são características inerentes aos lentivirus. A identificação do subtipo de vírus e o conhecimento da diversidade genética das cepas circulantes são fundamentais para o desenvolvimento estratégico de vacinas capazes de resultar na imunização do hospedeiro e no estabelecimento de testes diagnósticos. Objetivando isolar o material genético e realizar a caracterização molecular do vírus da imunodeficiência felina foram coletadas e analisadas amostras de sangue periférico de felinos portadores do FIV, co-habitantes de um abrigo aberto de felinos, em São Paulo, SP, em quatro momentos distintos, T0 (zero), no momento inicial da avaliação e seis, dez e quinze meses após a coleta inicial, correspondendo aos momentos T1, T2 e T3, respectivamente. Foram realizados testes hematológicos e bioquímicos nas quatro coletas com a finalidade de avaliar a evolução clínica da infecção. Adicionalmente foi realizado um estudo de variabilidade genética do FIV, com base no sequenciamento dos produtos amplificados dos gene env obtidos no estudo. Os envelopes clonados foram utilizados para transfectar células resultando na expressão das proteínas do envelope que possibilitaram estudos com os receptores celulares utilizados pelos isolados brasileiros. As análises das seqüências virais mostraram que todas as amostras, do abrigo, pertencem ao subtipo B. Foi observado um baixo percentual de mudança, da região estudada do vírus entre as quatro coletas. O fenômeno de &quot;quasispecies&quot; virais, bastante estudado no HIV, pode ser documentado em nossas amostras. Nos exames hematológicos e bioquímicos; hematócrito, hemoglobina, contagem total de leucócitos, proteína total e gamaglobulinas; dos animais infectados pelo FIV observou-se mudanças entre a primeira e quarta coleta demonstrando assim a importância dos testes utilizados no acompanhamento da infecção pelo FIV. Com relação aos dados com os receptores do FIV, os resultados apontam uma menor complexidade na interação entre os envelopes dos isolados do estudo com o receptor CD134 para proceder a infecção quando comparados com cepas virulentas do FIV. / FIV is an important viral pathogen that infects the domestic cat and causes a slow progressive degeneration of the immune system which eventually leads to a disease comparable to acquired immune deficiency syndrome (AIDS) in humans. Similar to all retroviruses, FIV has a relatively high evolutionary rate and genomic heterogeneity. The determination of subtype and the knowledge of genetic diversity of the current strains are very important to developing a protective vaccine and for the routine diagnosis of infection. The aim of this study was to isolate and characterize samples of feline immunodeficiency virus from cats from an open shelter in Sao Paulo, Brazil. All cats infected with FIV from this shelter were sampled on August 26th, 2007 (T0) and also six (T1), ten (T2) and fifteen (T3) months after the basal sampling (T0). In each sample, blood was analyzed for the following: complete hematology, clinical chemistry and serum protein electrophoresis. Hematological and clinical chemistry parameters were analyzed to determine laboratory parameters characteristic of disease progression which allow a better description of the chronic phase of the infection. Furthermore, analyses of the variants from each sample were performed in order to estimate the degree of divergence following infection with Brazilian strains. The FIV envelope glycoprotein gene from Brazilian FIV isolates cloned were transfected to investigate the receptor usage. The sequences of all virus of the study belong to subtype B. Little sequence variation was observed in circulating viruses between the samples from each infected cat. Quasispecies of FIV have been detected in this study. The following hematological and clinical chemistry parameters were changed in the FIV-infected cats between the first blood sampling and last blood sampling: packed cell volume (PCV), hemoglobin, total white blood cells (WBC), total protein and gamma globulin fractions. Monitoring of hematological and clinical chemistry parameters may prove useful for the evaluation of disease progress. Regarding receptors, our data are consistent with isolates of the study requiring a less complex interaction with CD134 for infection to proceed compared to the virulent FIV isolates.

En la primera parte se evalúan los efectos sedantes, adversos y sobre el sistema cardiorrespiratorio de la romifidina en la especie felina. Se utilizaron cinco y se realizaron 4 grupos experimentales: romifidina 200, 400 y 600 &#956;g/Kg IM y medetomidina 80 &#956;g/Kg IM. En la segunda parte se evalúa la combinación romifidina/ketamina en la especie felina. Se utilizaron siete gatos. Se realizaron 5 grupos experimentales: Romifidina 100 y 200 &#956;g/Kg con ketamina 7,5 y 10 mg/Kg y romifidina 200 &#956;g/Kg con ketamina 5 mg/Kg. Se monitorizó el grado de relajación muscular, la respuesta al clampado y el sistema cardiorrespiratorio durante 60 minutos. Los resultados obtenidos sugieren que el efecto sedante de la romifidina puede ser útil en premedicación anestésica y en intervenciones no dolorosas. La romifidina potencia la actividad de la ketamina, y su combinación compensa parcialmente los efectos adversos de la misma. / Firstly, the sedative, cardio respiratory and adverse effects produced for the administration of romifidine were evaluated in five cats. Four experimental groups were established: romifidine 200, 400 and 600 &#956;g/Kg in comparison to medetomidine 80 &#956;g/Kg. Secondly, the anaesthetic quality, cardiorespiratory and adverse effects produced by the mixture of romifidine and ketamine were studied in seven cats. Five experimental groups were established: Romifidine 100 &#956;g/Kg and ketamine 7.5 mg/Kg and 10 mg/Kg, romifidine 200 &#956;g/Kg and ketamine 5 mg/Kg, 7.5 mg/Kg, and 10 mg/Kg. The drugs were administred intramuscularly. The results of this experience suggest that romifidine could be a good alternative as a sedative for the development of non-painful procedures, as well as anaesthetic pre-medication. Romifidine enhances the anaesthetic effects of ketamine and the disadvantages of each compound are well remedied in the combination. This mixture in combination wit h opioids could be a chance to perform minor surgery procedures.