No description available.

No description available.

No description available.

No description available.

Objective: We sought to determine N-terminal proatrial natriuretic peptide concentrations [Nt-proANP] in plasma from cats with hypertrophic cardiomyopathy (HCM). Secondarily, we wished to evaluate the relationship between [Nt-proANP] and echocardiographic variables. Methods: Venous blood samples were obtained from seventeen cats with HCM and from nineteen healthy cats. Plasma [Nt-proANP] was determined using an ELISA assay. The relationship between plasma [Nt-proANP] and M-mode, 2-dimensional and Doppler echocardiographic variables was evaluated. Cats that were hyperthyroid or had evidence of renal disease were excluded from the study. Results: The mean plasma [Nt-proANP] was higher in cats with HCM (3.81 +/- 1.23 pmol/l) than in control cats (3.08 +/- 1.41 pmol/l); however, this difference was not statistically significant (p=0.17). There was a significant correlation between plasma [Nt-proANP] and left ventricular posterior wall thickness (r = 0.42; p=0.01). Additionally, plasma [Nt-proANP] was correlated with left atrial size (r = 0.35; p=0.03). A linear regression model was developed to further explore these relationships. LAs2D and LVPWd had an interactive effect on plasma [Nt-proANP] (R2 = 0.2737; p= 0.02). There was no correlation between any other echocardiographic variable and plasma [Nt-proANP]. There was no correlation between plasma [Nt-proANP] and heart rate (HR), body-weight, or age. Conclusions: Cats with HCM do not have significantly higher plasma [Nt-proANP] than normal cats. There was a significant linear relationship between [Nt-proANP] and LAs2D, LVPWd and the model that described their interaction. / Master of Science

A patogênese da Cardiomiopatia Chagásica Crônica (CCC) ainda é assunto de intenso debate. A CCC apresenta intenso infiltrado inflamatório no tecido cardíaco, onde os linfócitos T infiltrantes produzem citocinas inflamatórias, como IFN-gama e TNF-alfa. Adicionalmente, pacientes com CCC apresentam um pior prognóstico quando comparados aos portadores de outras cardiomiopatias de etiologia não inflamatória, como a cardiomiopatia dilatada idiopática (CDI) e a cardiomiopatia isquêmica (CI), sugerindo que mecanismos inflamatórios participam da patogênese e evolução da doença. Além disso, evidências anteriores de nosso grupo indicaram alterações do metabolismo energético na CCC. Neste trabalho, comparamos a expressão protéicado miocárdio de pacientes com CCC, CDI e CI e indivíduos sem cardiomiopatias, com foco em proteínas relacionadas ao metabolismo energético celular. Para a identificação do perfil de expressão protéica no miocárdio de pacientes com CCC, utilizamos a técnica de separação por eletroforese bidimensional, e a identificação das proteínas foi feita por espectrometria de massa. A maioria dos spots identificados corresponde a proteínas estruturais ou proteínas do metabolismo, principalmente do metabolismo energético. Foram identificadas também proteínas envolvidas na apoptose, em processos imunes e de resposta ao estresse. A análise da expressão protéica diferencial, utilizando marcação fluorescente, nos permitiu analisar o padrão de expressão das proteínas diferencialmente expressas no miocárdio de pacientes com CCC, CDI e CI e de indivíduos sem cardiomiopatias, dentro de um total de 683 spots e 230 proteínas distintas identificadas. Observamos que o padrão de expressão protéica do miocárdio de pacientes com CCC é o mais distinto em relação ao padrão de expressão protéica presente no miocárdio de indivíduos sem cardiomiopatias; e que o padrão de expressão das proteínas presentes no miocárdio de pacientes com CI é o que mais se assemelha ao padrão de indivíduos sem cardiomiopatias. Encontramos várias proteínas com expressão alterada em amostras de pacientes com CCC, CDI e CI em comparação com amostras de indivíduos sem cardiomiopatias, as quais desempenham papéis fundamentais em processos envolvidos na patologia de doenças cardiovasculares como apoptose (ex. catepsina D e Akt2), estresse oxidativo (ex. catalase), estresse do retículo endoplasmático (ex: proteína dissulfito isomerase), remodelamento cardíaco (ex: gelsolina) e outros. A análise individual das proteínas diferencialmente expressas entre os grupos de cardiomiopatia também mostrou que o miocárdio de pacientes com CCC apresenta expressão reduzida de várias proteínas mitocondriais associadas ao metabolismo energético nas vias da glicólise, ciclo de Krebs, beta-oxidação, na fosforilação oxidativa, e do complexo creatina-quinase - em comparação com miocárdio de indivíduos sem cardiomiopatias. Embora algumas dessas alterações tenham sido compartilhadas com a CDI, e em menor grau com a CI, observamos que os pacientes CCC apresentam o maior comprometimento do sistema creatina quinase, incluindo sua atividade enzimática. Também observamos que componentes do complexo enzimático da ATP sintase encontram-se reduzidos em amostras de pacientes com CCC em comparação aos indivíduos sem cardiomiopatia. Observamos também aumento de expressão de proteínas de stress incluindo estresse oxidativo, associadas à apoptose, e ao sistema imune no miocárdio de pacientes CCC, além da subunidade do imunoproteasomo e de proteínas associadas à degradação protéica. Em conjunto, nossos resultados sugerem que a diminuição de expressão das proteínas essenciais à geração de ATP, o aumento da expressão de proteínas associadas à apoptose e de proteínas do sistema imune no miocárdio de pacientes com CCC em comparação aos pacientes CI e CDI podem estar relacionados à pior evolução da CCC. Nossa análise de padrões de expressão protéica identificou conjuntos de proteínas capazes de discriminar as amostras de miocárdio por etiologia. Isto poderá auxiliar no diagnóstico e na descoberta de biomarcadores periféricos de cardiomiopatias, bem como ajudar na elucidação dos mecanismos de desenvolvimento da doença e de alterações estruturais / moleculares do miocárdio em resposta à inflamação crônica. / The pathogenesis of Chagas disease cardiomyopathy (CCC) is still controversial. CCC is characterized by an intense cardiac inflammatory infiltrate; infiltrating T lymphocytes produce inflammatory cytokines such as IFN-gamma and TNF-alpha. Patients afflicted by CCC display a worse prognosis when compared to patients afflicted by non-inflammatory cardiomyopathies such as idiopathic dilated cardiomyopathy (IDC) and ischemic cardiomyopathy (IC), suggesting that inflammatory mechanisms play a role in the pathogenesis and progression of the disease. In addition, previous evidence from our group suggested the presence of energy metabolism changes in CCC. In the present work, we compared the protein expression profile of the myocardium of patients with CCC, IDC, IC, and noncardiomyopathic subjects, with focus on energetic metabolism-related proteins. We used bidimensional electrophoresis to analyze the protein expression profile in the myocardium of patients afflicted by CCC, and proteins were identified by mass spectrometry. The majority of spots were identified as structural proteins or metabolism proteins, especially of energy metabolism. We were also able to identify apoptosis-, immune system- and stress response-related proteins. Using fluorescent labeling, we analyzed the differential expression profile in the myocardium of CCC, IDC and IC patients, from a total of 683 spots and 230 distinct proteins identified. We observed that the protein expression profile of CCC patients is the most distinct when compared to non-cardiomyopathic subjects. On the other hand, the protein expression profile of IC patients is similar, at some extent, to the expression profile of non-cardiomyopathic patients. We also found altered expression of proteins related to apoptosis (e.g. cathepsin D and Akt2), oxidative stress (e.g. catalase), endoplasmic reticulum stress (e.g. disulfilte isomerase protein), cardiac remodeling (e.g. gelsolin) among CCC, IDC and IC patients when compared to noncardiomyopathic patients. Most of these proteins, if not all, play fundamental roles in the pathogenesis of cardiovascular diseases. We also showed that the myocardium of patients afflicted by CCC display altered expression of several mitochondrial proteins associated to energy metabolism in the glycolysis, Krebs cycle, betaoxidation, oxidative phosphorylation, and creatine kinase complex when compared to non-cardiomyopathic subjects. Although some of these changes were shared with IDC samples, and, to a lesser extent, with CI samples, Western blot analysis demonstrated that CCC samples showed the most extreme reduction in protein expression of the creatine kinase system, including its enzymatic activity. We also observed with Western blot analysis that proteins from the ATP synthase complex (subunits alpha and beta) showed decreased expression in myocardium of CCC patients when compared to non-cardiomyopathic subjects and when compared to IC patients. We also observed an increase in the protein expression of stress proteins, including those involved in the oxidative stress response, those associated to apoptosis, and immune system proteins in CCC myocardium, along with increased expression of the immunoproteasome subunit and proteins associated to protein degradation. Taken together, our results suggest that diminished expression of proteins fundamental for ATP generation, increased expression of apoptosisassociated proteins and immune system proteins in the myocardium of CCC patients when compared to IC and IDC patients may be associated to CCC progression. The analysis of the protein expression profile has identified groups of proteins whose expression pattern is able to discriminate the myocardium samples by etiology. This may help to find novel peripheral biomarkers of CCC and other cardiomyopathies, as well as in the understanding of mechanisms of disease progression and structural/molecular alterations of the inflamed myocardium.

A patogênese da Cardiomiopatia Chagásica Crônica (CCC) ainda é assunto de intenso debate. A CCC apresenta intenso infiltrado inflamatório no tecido cardíaco, onde os linfócitos T infiltrantes produzem citocinas inflamatórias, como IFN-gama e TNF-alfa. Adicionalmente, pacientes com CCC apresentam um pior prognóstico quando comparados aos portadores de outras cardiomiopatias de etiologia não inflamatória, como a cardiomiopatia dilatada idiopática (CDI) e a cardiomiopatia isquêmica (CI), sugerindo que mecanismos inflamatórios participam da patogênese e evolução da doença. Além disso, evidências anteriores de nosso grupo indicaram alterações do metabolismo energético na CCC. Neste trabalho, comparamos a expressão protéicado miocárdio de pacientes com CCC, CDI e CI e indivíduos sem cardiomiopatias, com foco em proteínas relacionadas ao metabolismo energético celular. Para a identificação do perfil de expressão protéica no miocárdio de pacientes com CCC, utilizamos a técnica de separação por eletroforese bidimensional, e a identificação das proteínas foi feita por espectrometria de massa. A maioria dos spots identificados corresponde a proteínas estruturais ou proteínas do metabolismo, principalmente do metabolismo energético. Foram identificadas também proteínas envolvidas na apoptose, em processos imunes e de resposta ao estresse. A análise da expressão protéica diferencial, utilizando marcação fluorescente, nos permitiu analisar o padrão de expressão das proteínas diferencialmente expressas no miocárdio de pacientes com CCC, CDI e CI e de indivíduos sem cardiomiopatias, dentro de um total de 683 spots e 230 proteínas distintas identificadas. Observamos que o padrão de expressão protéica do miocárdio de pacientes com CCC é o mais distinto em relação ao padrão de expressão protéica presente no miocárdio de indivíduos sem cardiomiopatias; e que o padrão de expressão das proteínas presentes no miocárdio de pacientes com CI é o que mais se assemelha ao padrão de indivíduos sem cardiomiopatias. Encontramos várias proteínas com expressão alterada em amostras de pacientes com CCC, CDI e CI em comparação com amostras de indivíduos sem cardiomiopatias, as quais desempenham papéis fundamentais em processos envolvidos na patologia de doenças cardiovasculares como apoptose (ex. catepsina D e Akt2), estresse oxidativo (ex. catalase), estresse do retículo endoplasmático (ex: proteína dissulfito isomerase), remodelamento cardíaco (ex: gelsolina) e outros. A análise individual das proteínas diferencialmente expressas entre os grupos de cardiomiopatia também mostrou que o miocárdio de pacientes com CCC apresenta expressão reduzida de várias proteínas mitocondriais associadas ao metabolismo energético nas vias da glicólise, ciclo de Krebs, beta-oxidação, na fosforilação oxidativa, e do complexo creatina-quinase - em comparação com miocárdio de indivíduos sem cardiomiopatias. Embora algumas dessas alterações tenham sido compartilhadas com a CDI, e em menor grau com a CI, observamos que os pacientes CCC apresentam o maior comprometimento do sistema creatina quinase, incluindo sua atividade enzimática. Também observamos que componentes do complexo enzimático da ATP sintase encontram-se reduzidos em amostras de pacientes com CCC em comparação aos indivíduos sem cardiomiopatia. Observamos também aumento de expressão de proteínas de stress incluindo estresse oxidativo, associadas à apoptose, e ao sistema imune no miocárdio de pacientes CCC, além da subunidade do imunoproteasomo e de proteínas associadas à degradação protéica. Em conjunto, nossos resultados sugerem que a diminuição de expressão das proteínas essenciais à geração de ATP, o aumento da expressão de proteínas associadas à apoptose e de proteínas do sistema imune no miocárdio de pacientes com CCC em comparação aos pacientes CI e CDI podem estar relacionados à pior evolução da CCC. Nossa análise de padrões de expressão protéica identificou conjuntos de proteínas capazes de discriminar as amostras de miocárdio por etiologia. Isto poderá auxiliar no diagnóstico e na descoberta de biomarcadores periféricos de cardiomiopatias, bem como ajudar na elucidação dos mecanismos de desenvolvimento da doença e de alterações estruturais / moleculares do miocárdio em resposta à inflamação crônica. / The pathogenesis of Chagas disease cardiomyopathy (CCC) is still controversial. CCC is characterized by an intense cardiac inflammatory infiltrate; infiltrating T lymphocytes produce inflammatory cytokines such as IFN-gamma and TNF-alpha. Patients afflicted by CCC display a worse prognosis when compared to patients afflicted by non-inflammatory cardiomyopathies such as idiopathic dilated cardiomyopathy (IDC) and ischemic cardiomyopathy (IC), suggesting that inflammatory mechanisms play a role in the pathogenesis and progression of the disease. In addition, previous evidence from our group suggested the presence of energy metabolism changes in CCC. In the present work, we compared the protein expression profile of the myocardium of patients with CCC, IDC, IC, and noncardiomyopathic subjects, with focus on energetic metabolism-related proteins. We used bidimensional electrophoresis to analyze the protein expression profile in the myocardium of patients afflicted by CCC, and proteins were identified by mass spectrometry. The majority of spots were identified as structural proteins or metabolism proteins, especially of energy metabolism. We were also able to identify apoptosis-, immune system- and stress response-related proteins. Using fluorescent labeling, we analyzed the differential expression profile in the myocardium of CCC, IDC and IC patients, from a total of 683 spots and 230 distinct proteins identified. We observed that the protein expression profile of CCC patients is the most distinct when compared to non-cardiomyopathic subjects. On the other hand, the protein expression profile of IC patients is similar, at some extent, to the expression profile of non-cardiomyopathic patients. We also found altered expression of proteins related to apoptosis (e.g. cathepsin D and Akt2), oxidative stress (e.g. catalase), endoplasmic reticulum stress (e.g. disulfilte isomerase protein), cardiac remodeling (e.g. gelsolin) among CCC, IDC and IC patients when compared to noncardiomyopathic patients. Most of these proteins, if not all, play fundamental roles in the pathogenesis of cardiovascular diseases. We also showed that the myocardium of patients afflicted by CCC display altered expression of several mitochondrial proteins associated to energy metabolism in the glycolysis, Krebs cycle, betaoxidation, oxidative phosphorylation, and creatine kinase complex when compared to non-cardiomyopathic subjects. Although some of these changes were shared with IDC samples, and, to a lesser extent, with CI samples, Western blot analysis demonstrated that CCC samples showed the most extreme reduction in protein expression of the creatine kinase system, including its enzymatic activity. We also observed with Western blot analysis that proteins from the ATP synthase complex (subunits alpha and beta) showed decreased expression in myocardium of CCC patients when compared to non-cardiomyopathic subjects and when compared to IC patients. We also observed an increase in the protein expression of stress proteins, including those involved in the oxidative stress response, those associated to apoptosis, and immune system proteins in CCC myocardium, along with increased expression of the immunoproteasome subunit and proteins associated to protein degradation. Taken together, our results suggest that diminished expression of proteins fundamental for ATP generation, increased expression of apoptosisassociated proteins and immune system proteins in the myocardium of CCC patients when compared to IC and IDC patients may be associated to CCC progression. The analysis of the protein expression profile has identified groups of proteins whose expression pattern is able to discriminate the myocardium samples by etiology. This may help to find novel peripheral biomarkers of CCC and other cardiomyopathies, as well as in the understanding of mechanisms of disease progression and structural/molecular alterations of the inflamed myocardium.

Submitted by Jaqueline Silva (jtas29@gmail.com) on 2014-12-12T19:36:47Z No. of bitstreams: 2 license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) Dissertação-Adriana Sebba Barroso de Souza Marques.pdf: 867953 bytes, checksum: 6484d53b38c78accaea85498548eb55f (MD5) / Approved for entry into archive by Jaqueline Silva (jtas29@gmail.com) on 2014-12-16T09:23:56Z (GMT) No. of bitstreams: 2 license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) Dissertação-Adriana Sebba Barroso de Souza Marques.pdf: 867953 bytes, checksum: 6484d53b38c78accaea85498548eb55f (MD5) / Made available in DSpace on 2014-12-16T09:23:56Z (GMT). No. of bitstreams: 2 license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) Dissertação-Adriana Sebba Barroso de Souza Marques.pdf: 867953 bytes, checksum: 6484d53b38c78accaea85498548eb55f (MD5) Previous issue date: 2013-12-20 / Background: Treatment with stem cells in various cardiomyopathies may be related to the increase in arrhythmias. Objective: To determine whether intracoronary injection of stem cells in patients with Chagas cardiomyopathy is associated with increased frequency of ventricular arrhythmias, compared to the control group. Methods: A retrospective cohort study that evaluatedt he medical records of 60 patients Who participated previously on sectional study.The following data was collected : age, sex , and drugs used and Holter variables that demonstrated the presence of arrhythmias.Holter was performed in four stages: randomization , 2 , 6 and 12 months segments. The control group (CG) received medical treatment and intracoronary injection of placebo and the study group (SG) drug treatment and autologous stem cell implant. Results: There was no difference between EG and CG analyzing the criteria of arrhythmia. In the intra-group analysis, significant difference was found between the Holter tests study group in the variable of total ventricular ectopic compared with baseline, being between H1 and H2 p=0.014, between H1 and H3 p=0.004, between H1and H4 p=0.014. The variable non-sustained ventricular tachycardia between H1 and H3 with p = 0.036. Conclusion: The intracoronary injection of stem cells did not increase the incidence of ventricular arrhythmias in patients with Chagas cardiomopatia compared to the control group. / Fundamento: O tratamento com células-tronco nas diversas cardiomiopatias pode estar relacionado ao aumento nas arritmias. Objetivo: Determinar se a injeção intracoronária de células-tronco em portadores de cardiomiopatia chagásica está associada ao aumento da frequência de arritmias ventriculares, comparado ao grupo controle. Método: Estudo de coorte retrospectivo que avaliou o prontuário de 60 pacientes que participaram de estudo transversal anterior. Foram coletados os seguintes dados: idade, sexo, medicamentos utilizados e variáveis do Holter que demonstraram presença de arritmia. O Holter foi realizado em quatro momentos: randomização, 2, 6 e 12 meses de seguimento. O grupo controle (GC) recebeu tratamento medicamentoso e injeção intracoronária de placebo e o grupo estudo (GE) tratamento medicamentoso e implante autólogo de células tronco. Resultados: Não houve diferença entre o GE e o GC nos critérios de arritmia analisados. Na analise intra-grupo foi encontrado diferença com significância entre os exames de HOLTER do grupo estudo na variável total de extrassístoles ventriculares comparado com o basal, sendo entre H1 e H2 p=0.014, entre H1 e o H3 p=0.004, entre H1 e H4 p=0.014. A variável taquicardia ventricular não sustentada entre H1 e H3 com p=0.036. Conclusão: A injeção intracoronária de células-tronco não aumentou a incidência de arritmias ventriculares em pacientes com cardiomopatia chagásica comparada ao grupo controle.

Dilated (DCM) and ischemic cardiomyopathies (ICM) are associated with cardiac remodeling, where the ubiquitin–proteasome system (UPS) holds a central role. Little is known about the UPS and its alterations in patients suffering from DCM or ICM. The aim of this study is to characterize the UPS activity in human heart tissue from cardiomyopathy patients. Myocardial tissue from ICM (n = 23), DCM (n = 28), and control (n = 14) patients were used to quantify ubiquitinylated proteins, E3-ubiquitin-ligases muscle-atrophy-F-box (MAFbx)/atrogin-1, muscle-RING-finger-1 (MuRF1), and eukaryotic-translation-initiation-factor-4E (eIF4E), by Western blot. Furthermore, the proteasomal chymotrypsin-like and trypsin-like peptidase activities were determined fluorometrically. Enzyme activity of NAD(P)H oxidase was assessed as an index of reactive oxygen species production. The chymotrypsin- (p = 0.71) and caspase-like proteasomal activity (p = 0.93) was similar between the groups. Trypsin-like proteasomal activity was lower in ICM (0.78 ± 0.11 µU/mg) compared to DCM (1.06 ± 0.08 µU/mg) and control (1.00 ± 0.06 µU/mg; p = 0.06) samples. Decreased ubiquitin expression in both cardiomyopathy groups (ICM vs. control: p < 0.001; DCM vs. control: p < 0.001), as well as less ubiquitin-positive deposits in ICM-damaged tissue (ICM: 4.19% ± 0.60%, control: 6.28% ± 0.40%, p = 0.022), were detected. E3-ligase MuRF1 protein expression (p = 0.62), NADPH-oxidase activity (p = 0.63), and AIF-positive cells (p = 0.50). Statistical trends were detected for reduced MAFbx protein expression in the DCM-group (p = 0.07). Different levels of UPS components, E3 ligases, and UPS activation markers were observed in myocardial tissue from patients affected by DCM and ICM, suggesting differential involvement of the UPS in the underlying pathologies.

Thesis (PhD)--Stellenbosch University, 2004. / Bibliography / ENGLISH ABSTRACT: Heart failure due to cardiomyopathy or cardiac conduction disease is a major cause of mortality and morbidity in both developed and developing countries. Although defined as separate clinical entities, inherited forms of cardiomyopathies and cardiac conduction disorders have been identified that present with overlapping clinical features and/or have common molecular aetiologies. The objective of the present study was to identify the molecular cause of progressive familial heart block type II (PFHBII), an inherited cardiac conduction disorder that segregates in a South African Caucasian Afrikaner family (Brink and Torrington, 1977). The availability of family data tracing the segregation of PFHBII meant that linkage analysis could be employed to identify the chromosomal location of the disease-causative gene. Human Genome Project (HGP) databases have provided additional resources to facilitate the identification of positional candidate genes. Clinical examinations were performed on individuals of the PFHBII-affected family, and, where available, clinical records of subjects examined in a previous study by Brink and Torrington (1977) were re-assessed. Retrospective data suggested redefining the classification of PFHBII. Subsequently, linkage analysis was used to test described dilated cardiomyopathy (DCM), hypertrophic cardiomyopathy (HCM) and cardiac conduction-causative loci on chromosomes 1, 2, 3, 6, 7, 9, 11, 14, 15 and 19 for their involvement in the development of PFHBII. Once a locus was mapped, bioinformatics tools were applied to identify and prioritise positional candidate genes for mutation screening. The retrospective and prospective clinical study redefined PFHBII as a cardiac conduction and DCM-associated disorder and simultaneously allowed more family members to be traced. Fortuitously, candidate loci linkage analysis mapped the PFHBII locus to chromosome 1q32, to a region that overlapped a previously described DCM-associated disorder (CMD1D), by the generation of a maximum pairwise lod score of 3.13 at D1S3753 (theta [θ]=0.0) and a maximum multipoint lod score of 3.7 between D1S3753 and D1S414. However, genetic fine mapping and haplotype analysis placed the PFHBII-causative locus distal to the CMD1D locus, within a 3.9 centimorgan (cM) interval on chromosome 1q32.2-q32.3, telomeric of D1S70 and centromeric of D1S505. Bioinformatics analyses prioritised seven candidate genes for mutation analysis, namely, a gene encoding a potassium channel (KCNH1), an extracellular matrix protein (LAMB3), a protein phosphatase (PPP2R5A), an adapter protein that interacts with a cytoskeletal protein (T3JAM), a putative acyltransferase (KIAA0205) and two genes encoding proteins possibly involved in energy homeostasis (RAMP and VWS59). The PFHBII-causative mutation was not identified, although single sequence variations were identified in four of the seven candidate genes that were screened. Although the molecular aetiology was not established, the present study defined the underlying involvement of DCM in the pathogenesis of PFHBII. The new clinical classification of PFHBII has been published (Fernandez et al., 2004) and should lead to tracing more affected individuals in South Africa or elsewhere. The identification of a novel disease-causative locus may point toward the future identification of a new DCM-associated aetiology, which, in turn, might provide insights towards understanding the associated molecular pathophysiologies of heart failure. / AFRIKAANSE OPSOMMING: Hartversaking as gevolg van kardiomiopatie of kardiale geleidingsiekte is ‘n hoof-oorsaak van mortaliteit and morbiditeit in beide ontwikkelde en ontwikkelende lande. Alhoewel gedefinieer as verskillende kliniese entiteite is oorerflike vorms van kardiomiopatie en kardiale geleidingsstoornisse geïdentifiseer met oorvleuelende kliniese eienskappe en/of molukulêre oorsake. Die doelwit van hierdie studie was om die molukulêre oorsaak van progressiewe familiële hartblok tipe II (PFHBII), ‘n oorerflike kardiale geleidingsstoornis, wat in ‘n Suid-Afrikaanse Kaukasiër familie segregeer (Brink en Torrington, 1977), te identifiseer. Die beskikbaarheid van familie data, beteken dat koppelingsanalise gebruik kan word om die chromosomale posisie van die siekte-veroorsakende geen te identifiseer. Menslike Genoom Projek (MGP) databanke het addisionele hulpbronne beskikbaar gestel om die identifikasie van posisionele kandidaat gene te vergemaklik. Kliniese ondersoeke is uitgevoer op PFHBII-geaffekteerde familielede, en waar beskikbaar is kliniese rekords van persone, wat in ‘n vorige studie deur Brink en Torrington (1977) geassesseer was, herontleed. Retrospektiewe data-analise het die kliniese herdefinisie van PFHBII voorgestel. Daarna is koppelingsanalise gebruik om dilateerde kardiomiopatie (DKM), hipertrofiese kardiomiopatie (HKM) en kardiale geleidingssiekte-veroorsakende loki op chromosoom 1, 2, 3, 6, 7, 9, 11, 14, 15 en 19 te ondersoek vir hul moontlike bydrae tot die ontwikkeling van PFHBII. Toe die lokus gekarteer was, is bioinformatiese ondersoeke gebruik om posisionele kandidaat gene te identifiseer en prioritiseer vir mutasie analise. Die retrospektiewe en prospektiewe kliniese ondersoek het PFHBII herdefinieer as ‘n geleidingsstoornis en DKM-verbonde siekte, en terselfde tyd het dit gelei tot die opsporing van nog familielede. Toevallig het kandidaat loki-analise die PFHBII lokus op chromosoom 1q32 gekarteer, na ‘n gebied wat met ‘n voorheen-beskyfde DKM-verbonde stoornis (CMD1D) oorvleuel, met die opwekking van ‘n makisimum paargewyse lod-getal van 3.13 by D1S3753 (theta [θ] = 0.0) en ‘n maksimum multipunt lod-getal van 3.7 tussen D1S3753 en D1S414. Genetiese fynkartering en haplotipe-analise het die PFHBII-veroorsakende lokus afwaards van die CMD1D lokus geplaas, in ‘n 3.9 centimorgan (cM) gebied op chromosoom 1q32.2-q32.3, telomeries van D1S70 en sentromeries van D1S505. Bioinformatiese analise het daarnatoe gelei dat sewe kandidaat gene vir mutasie analise geprioritiseerd is, naamlik, gene wat onderskeidelik ‘n kalium kanaal (KCNH1), ‘n ekstrasellulêre matriksproteïen (LAMB3), ‘n proteïen fosfatase (PPP2R5A), ‘n aansluiter proteïen wat met ‘n sitoskilet proteïen bind (T3JAM), ‘n asieltansferase (KIAA0205) en twee gene moontlik betrokke in energie homeostase (RAMP en VWS59) enkodeer. Die PFHBII-veroorsakende geen is nie geïdentifiseer nie, alhoewel enkele volgorde-wisselings geïdentifiseer is in vier van die sewe geanaliseerde kandidaat gene. Alhowel die molekulêre oorsaak van die siekte nie vasgestel is nie, het die huidige studie die onderliggende betrokkenheid van DKM in die pathogenese van PFHBII gedefinieer. Die nuwe kliniese klassifikasie van PFHBII is gepubiliseer (Fernandez et al., 2004) en sal lei tot die identifisering van nog geaffekteerde persone in Suid Afrika of in ander lande. Die identifikasie van ‘n nuwe siekte-verbonde lokus mag lei tot die toekomstige identifikasie van ‘n nuwe DKM-verbonde genetiese oorsaak wat, opsig self, dalk insig kan gee in die molekulêre patofisiologie van hartversaking.