Tierärztl. Hochsch., Diss., 2004--Hannover.

Six different isoforms of Type IV collagen (colIVα1-6) have been identified. The individual isoforms of colIV are termed alpha chains and are translated from six different COLIV genes (COLIVA1-A6). Collagen Type IV gene products compose the structural framework of basement membranes. The glomerular basement membrane (GBM) is a specialized basement membrane involved in the ultrafiltration processes of the kidney. The colIVα1-α5 chains are expressed in the human GBM while the colIV α1-α6 chains are expressed in the canine GBM. Many inherited diseases of the kidney have been reported and mutations in genes regulating kidney function have been identified. Alport syndrome (AS) is the most common form of human hereditary nephritis (HN). AS is defined as an inherited progressive kidney disorder associated with sensoneural deafness and is characterized by extensive thickening and multilamminar splitting of the GBM when examined by electron microscopy. AS has both X-linked (XLAS) and autosomal (ARAS) modes of inheritance. Mutations in the COLIVA5 gene are responsible for XLAS. A form of HN with characteristic splitting of the GBM with X-linked inheritance has been described in Samoyed dogs. A specific mutation in the COLIVA5 gene has been identified in Samoyed dogs affected with HN. Mutations in the COLIVA3 and COLIVA4 genes are responsible for ARAS. A form of HN has been identified in English cocker spaniel dogs (ECS) that has been described as autosomal in inheritance and includes GBM abnormalities including extensive lammination characteristic of ARAS. Both ARAS and ECS-HN show loss of the colIVA3 and colIVA4 chains in the GBM when examined with monoclonal anitibodies. ECS-HN has been hypothesized to have the same molecular basis of disease as ARAS. As such, we have isolated and characterized canine COLIVA3 and COLIVA4 sequences from normal dogs and ECS dogs affected with HN and compared the coding regions of these candidate genes.

Six different isoforms of Type IV collagen (colIVα1-6) have been identified. The individual isoforms of colIV are termed alpha chains and are translated from six different COLIV genes (COLIVA1-A6). Collagen Type IV gene products compose the structural framework of basement membranes. The glomerular basement membrane (GBM) is a specialized basement membrane involved in the ultrafiltration processes of the kidney. The colIVα1-α5 chains are expressed in the human GBM while the colIV α1-α6 chains are expressed in the canine GBM. Many inherited diseases of the kidney have been reported and mutations in genes regulating kidney function have been identified. Alport syndrome (AS) is the most common form of human hereditary nephritis (HN). AS is defined as an inherited progressive kidney disorder associated with sensoneural deafness and is characterized by extensive thickening and multilamminar splitting of the GBM when examined by electron microscopy. AS has both X-linked (XLAS) and autosomal (ARAS) modes of inheritance. Mutations in the COLIVA5 gene are responsible for XLAS. A form of HN with characteristic splitting of the GBM with X-linked inheritance has been described in Samoyed dogs. A specific mutation in the COLIVA5 gene has been identified in Samoyed dogs affected with HN. Mutations in the COLIVA3 and COLIVA4 genes are responsible for ARAS. A form of HN has been identified in English cocker spaniel dogs (ECS) that has been described as autosomal in inheritance and includes GBM abnormalities including extensive lammination characteristic of ARAS. Both ARAS and ECS-HN show loss of the colIVA3 and colIVA4 chains in the GBM when examined with monoclonal anitibodies. ECS-HN has been hypothesized to have the same molecular basis of disease as ARAS. As such, we have isolated and characterized canine COLIVA3 and COLIVA4 sequences from normal dogs and ECS dogs affected with HN and compared the coding regions of these candidate genes.

Ecodopplercardiografia é o estudo do coração e grandes vasos por meio da ultra-sonografia, no qual são obtidas informações importantes de caráter qualitativo e quantitativo sobre o sistema cardiovascular. O objetivo deste trabalho foi estabelecer os parâmetros ecodopplercardiográficos de cães da raça Cocker Spaniel Inglês e correlacioná-los entre si e com medidas biométricas corpóreas. No total, foram utilizados 22 cães, da raça Cocker Spaniel Inglês, 7 machos e 15 fêmeas, com idades entre 1 e 7 anos (3,47 ± 1,7) e peso corpóreo entre 11,2 e 18 Kg (13,25 ± 1,68), sem alterações cardiovasculares (previamente verificadas através da anamnese, exame físico, radiografia do tórax, eletrocardiografia e mensuração da pressão arterial), correlacioná-los entre si e com medidas biométricas corpóreas. Após a obtenção dos valores de referência dos parâmetros em modo M e Doppler observou-se que as medidas biométricas corpóreas correlacionaram-se entre si, mas não se correlacionaram com os parâmetros ecodopplercardiográficos, à exceção do comprimento do animal. Não houve, também, influência do sexo sobre estes parâmetros. / Ecocardiography is the study of the heart and great vessels through ultrasounds that allows qualitative and quantitative cardiovascular evaluation. The objective of this work was to stablish Doppler echocardiographic parameters and to correlate it with themselves and with body size parameters of English Cocker Spaniel dogs. A total of 22 English Cocker Spaniels dogs, 7 males and 15 females, aged 1 to 7 (3,47 ± 1,7), weighted 11,2 to 18 Kg (13,25 ± 1,68), without cardiovascular alterations (previously verified by means of anamnese, physical exams, radiography, electrocardiography and arterial blood pressure measurement) were used. After Doppler echocardiographic examination and body size measurements, it was possible to obtain M mode and Doppler reference values. Body size measures correlated among themselves but there has not been noted significant correlation between Doppler echocardiographic parameters and body size, except body lenght. Sex did not influence any Doppler echocardiographic variables.

The domestic dog, Canis familiaris, has over 450 naturally occurring inherited diseases. Over half of these diseases are clinically similar to human diseases making the dog an excellent model in which to study human hereditary diseases. Alport syndrome (AS), a group of heterogeneous, hereditary renal diseases, is one example of such a human disease. The disease is transmitted in three fashions: X-linked, autosomal recessive, and autosomal dominant. AS is caused by mutations in COL4α3, COL4α4 or COL4α5, all members of the type IV collagen family. The proteins products of these genes along with those of the other type IV collagen family members (COL4α1, COL4α2, and COL4α6) are structural components of basement membranes throughout the body. This dissertation describes the measurement of mRNA transcripts in two canine models of AS: a mixed breed model of X-linked AS (XLAS) and the English Cocker Spaniel (ECS) model of autosomal recessive AS (ARAS). The work done revealed a decrease in COL4α4 transcripts. The similarity between the decrease of COL4α5 in the XLAS model and that for COL4α4 in the ARAS model lead to the investigation of COL4α4 as the gene harboring the mutation causative for ARAS in the ECS. Upon sequencing COL4α4, the causative mutation was determined to be an A to T transversion in exon 3. To provide an in vitro model to study type IV collagens, a protocol was designed and experimentally validated to isolate and culture canine Sertoli cells. Canine testes cells were isolated and cultured. Cells were verified as Sertoli cells through positive identification of both SOX9 and Clusterin B proteins, along with sequence verification of SOX9 transcripts. This in vitro model provides a tool to further study the type IV collagens. Overall, the research described herein lead to the identification of the mutation causative for ARAS in the ECS. With this knowledge a genetic test was developed to test for the disease. This research also provided valuable information about the transcript levels of type IV collagens in two models of AS, and provided a novel model in which to study the type IV collagens further.

The domestic dog, Canis familiaris, has over 450 naturally occurring inherited diseases. Over half of these diseases are clinically similar to human diseases making the dog an excellent model in which to study human hereditary diseases. Alport syndrome (AS), a group of heterogeneous, hereditary renal diseases, is one example of such a human disease. The disease is transmitted in three fashions: X-linked, autosomal recessive, and autosomal dominant. AS is caused by mutations in COL4α3, COL4α4 or COL4α5, all members of the type IV collagen family. The proteins products of these genes along with those of the other type IV collagen family members (COL4α1, COL4α2, and COL4α6) are structural components of basement membranes throughout the body. This dissertation describes the measurement of mRNA transcripts in two canine models of AS: a mixed breed model of X-linked AS (XLAS) and the English Cocker Spaniel (ECS) model of autosomal recessive AS (ARAS). The work done revealed a decrease in COL4α4 transcripts. The similarity between the decrease of COL4α5 in the XLAS model and that for COL4α4 in the ARAS model lead to the investigation of COL4α4 as the gene harboring the mutation causative for ARAS in the ECS. Upon sequencing COL4α4, the causative mutation was determined to be an A to T transversion in exon 3. To provide an in vitro model to study type IV collagens, a protocol was designed and experimentally validated to isolate and culture canine Sertoli cells. Canine testes cells were isolated and cultured. Cells were verified as Sertoli cells through positive identification of both SOX9 and Clusterin B proteins, along with sequence verification of SOX9 transcripts. This in vitro model provides a tool to further study the type IV collagens. Overall, the research described herein lead to the identification of the mutation causative for ARAS in the ECS. With this knowledge a genetic test was developed to test for the disease. This research also provided valuable information about the transcript levels of type IV collagens in two models of AS, and provided a novel model in which to study the type IV collagens further.

Ecodopplercardiografia é o estudo do coração e grandes vasos por meio da ultra-sonografia, no qual são obtidas informações importantes de caráter qualitativo e quantitativo sobre o sistema cardiovascular. O objetivo deste trabalho foi estabelecer os parâmetros ecodopplercardiográficos de cães da raça Cocker Spaniel Inglês e correlacioná-los entre si e com medidas biométricas corpóreas. No total, foram utilizados 22 cães, da raça Cocker Spaniel Inglês, 7 machos e 15 fêmeas, com idades entre 1 e 7 anos (3,47 ± 1,7) e peso corpóreo entre 11,2 e 18 Kg (13,25 ± 1,68), sem alterações cardiovasculares (previamente verificadas através da anamnese, exame físico, radiografia do tórax, eletrocardiografia e mensuração da pressão arterial), correlacioná-los entre si e com medidas biométricas corpóreas. Após a obtenção dos valores de referência dos parâmetros em modo M e Doppler observou-se que as medidas biométricas corpóreas correlacionaram-se entre si, mas não se correlacionaram com os parâmetros ecodopplercardiográficos, à exceção do comprimento do animal. Não houve, também, influência do sexo sobre estes parâmetros. / Ecocardiography is the study of the heart and great vessels through ultrasounds that allows qualitative and quantitative cardiovascular evaluation. The objective of this work was to stablish Doppler echocardiographic parameters and to correlate it with themselves and with body size parameters of English Cocker Spaniel dogs. A total of 22 English Cocker Spaniels dogs, 7 males and 15 females, aged 1 to 7 (3,47 ± 1,7), weighted 11,2 to 18 Kg (13,25 ± 1,68), without cardiovascular alterations (previously verified by means of anamnese, physical exams, radiography, electrocardiography and arterial blood pressure measurement) were used. After Doppler echocardiographic examination and body size measurements, it was possible to obtain M mode and Doppler reference values. Body size measures correlated among themselves but there has not been noted significant correlation between Doppler echocardiographic parameters and body size, except body lenght. Sex did not influence any Doppler echocardiographic variables.

A cardiomiopatia dilatada (CMD) é uma das cardiopatias mais frequentes em cães, sendo a redução da contratilidade miocárdica uma de suas principais características. Dentre as raças predispostas, destaca-se o Cocker Spaniel Inglês. O diagnóstico baseia-se nos achados da ecocardiografia convencional. Todavia, as recentes técnicas ecocardiográficas de Doppler tecidual, como a determinação das velocidades miocárdicas, o registro da deformação (Df) e da taxa de deformação (TDf) miocárdicas, podem identificar padrões característicos de disfunção, antes mesmo do surgimento de anormalidades na ecocardiografia convencional. Com o objetivo de investigar os padrões de disfunção miocárdica ventricular, por meio das técnicas retro-mencionadas, foram incluídos 32 cães da raça Cocker Spaniel Inglês, sendo 16 com diagnóstico de cardiomiopatia dilatada e 16 considerados hígidos, para fins de grupo controle. O estudo Doppler tecidual possibilitou a identificação de disfunção miocárdica ventricular sistólica e diastólica, em ambos os ventrículos dos cães com CMD. No ventrículo esquerdo encontrou-se disfunção miocárdica longitudinal e transversal, caracterizada por menor velocidade miocárdica sistólica, retardo eletromecânico, contrações pós-sistólicas longitudinais, redução na Df e TDf sistólicas, além de distúrbio no relaxamento miocárdico. Por sua vez, diminuição da Df miocárdica sistólica longitudinal e retardo no relaxamento miocárdico caracterizaram a disfunção ventricular direita. O presente estudo identificou, de maneira inédita, padrões de disfunção miocárdica, obtidos por meio de Doppler tecidual, em uma população de cães da raça Cocker Spaniel Inglês com CMD. / Dilated cardiomyopathy (DCM) is one of the most common heart diseases in dogs and its main feature is reduced contractility. English Cocker Spaniel is among predisposed breeds. Diagnosis is based on conventional echocardiographic findings. However, recent tissue Doppler echocardiographic techniques, such as myocardial velocities determination and recordings of myocardial strain (St) and strain rate (SR), can identify characteristic patterns of dysfunction, even before the onset of abnormalities in conventional echocardiography. In order to investigate the patterns of ventricular myocardial dysfunction by means of retro-mentioned techniques, 32 English Cocker Spaniels were studied, being 16 diagnosed with DCM and 16 considered healthy for control purpose. Tissue Doppler study allowed identification of systolic and diastolic ventricular myocardial dysfunction in both ventricles of dogs with DCM. Left ventricular findings included longitudinal and transversal myocardial dysfunction, characterized by lower systolic myocardial velocity, electromechanical delay, longitudinal post systolic contractions, reduced systolic St and SR, and myocardial relaxation disturbance. In turn, reduced longitudinal systolic myocardial St and delayed myocardial relaxation characterized right ventricular dysfunction. The present study identified, in an unprecedented way, patterns of dysfunction, obtained by tissue Doppler, in a dog population of English Cocker Spaniels with DCM.

A cardiomiopatia dilatada (CMD) é uma das cardiopatias mais frequentes em cães, sendo a redução da contratilidade miocárdica uma de suas principais características. Dentre as raças predispostas, destaca-se o Cocker Spaniel Inglês. O diagnóstico baseia-se nos achados da ecocardiografia convencional. Todavia, as recentes técnicas ecocardiográficas de Doppler tecidual, como a determinação das velocidades miocárdicas, o registro da deformação (Df) e da taxa de deformação (TDf) miocárdicas, podem identificar padrões característicos de disfunção, antes mesmo do surgimento de anormalidades na ecocardiografia convencional. Com o objetivo de investigar os padrões de disfunção miocárdica ventricular, por meio das técnicas retro-mencionadas, foram incluídos 32 cães da raça Cocker Spaniel Inglês, sendo 16 com diagnóstico de cardiomiopatia dilatada e 16 considerados hígidos, para fins de grupo controle. O estudo Doppler tecidual possibilitou a identificação de disfunção miocárdica ventricular sistólica e diastólica, em ambos os ventrículos dos cães com CMD. No ventrículo esquerdo encontrou-se disfunção miocárdica longitudinal e transversal, caracterizada por menor velocidade miocárdica sistólica, retardo eletromecânico, contrações pós-sistólicas longitudinais, redução na Df e TDf sistólicas, além de distúrbio no relaxamento miocárdico. Por sua vez, diminuição da Df miocárdica sistólica longitudinal e retardo no relaxamento miocárdico caracterizaram a disfunção ventricular direita. O presente estudo identificou, de maneira inédita, padrões de disfunção miocárdica, obtidos por meio de Doppler tecidual, em uma população de cães da raça Cocker Spaniel Inglês com CMD. / Dilated cardiomyopathy (DCM) is one of the most common heart diseases in dogs and its main feature is reduced contractility. English Cocker Spaniel is among predisposed breeds. Diagnosis is based on conventional echocardiographic findings. However, recent tissue Doppler echocardiographic techniques, such as myocardial velocities determination and recordings of myocardial strain (St) and strain rate (SR), can identify characteristic patterns of dysfunction, even before the onset of abnormalities in conventional echocardiography. In order to investigate the patterns of ventricular myocardial dysfunction by means of retro-mentioned techniques, 32 English Cocker Spaniels were studied, being 16 diagnosed with DCM and 16 considered healthy for control purpose. Tissue Doppler study allowed identification of systolic and diastolic ventricular myocardial dysfunction in both ventricles of dogs with DCM. Left ventricular findings included longitudinal and transversal myocardial dysfunction, characterized by lower systolic myocardial velocity, electromechanical delay, longitudinal post systolic contractions, reduced systolic St and SR, and myocardial relaxation disturbance. In turn, reduced longitudinal systolic myocardial St and delayed myocardial relaxation characterized right ventricular dysfunction. The present study identified, in an unprecedented way, patterns of dysfunction, obtained by tissue Doppler, in a dog population of English Cocker Spaniels with DCM.