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<p>Peptidoglycan (PG) remodelling and cell division are two important cellular processes that are the major target of antibiotics. Due to rising resistance, the need for new antibiotics today has never been greater. Therefore it is important to fill the gaps in our understanding of these two important processes in order to discover new and promising antibiotic targets. Peptidoglycan synthesis and remodelling is a highly coordinated event that involves a wide number of enzymes and processes which are not well understood. N-acetylmuramoyl-L-alanine amidases, whose function is to cleave the amide linkage between the stem peptides and the lactyl moiety of N-acetylmuramic acid, is a major class of PG-active proteins. Their role in daughter cell separation during cell division is well established in <em>Escherichia coli</em> however little is known about it in other systems. Using enzymatic assays we characterize AmiC as a novel amidase in <em>Pseudomonas aeruginosa. </em>Through mutational analysis and microscopy we show that AmiB and AmiC are required for daughter cell separation. A deletion of both enzymes results in a cell chaining phenotype with abnormal cell morphology. Transmission electron microscopy reveals that the double mutant is arrested at the septal peptidoglycan separation step. In addition to cell chaining, the ∆<em>amiB/amiC</em> mutant exhibits a significant increase in susceptibility to antibiotics. We also demonstrate that the LysM motif of AmiB is not required for its role in cell separation. Furthermore, the <em>amiB</em> mutant has significantly shorter cells than the wildtype indicating an additional role for the enzyme in the cell. Lastly, through a novel bioinformatics strategy we identify PA5047 as a potential PG amidase.</p> / Bachelor of Science (BSc)

We present a case of a previously asymptomatic 63-year-old woman who presented with worsening dyspnoea for 3 weeks. Initial transthoracic and later transoesophageal echocardiography confirmed biventricular non-compaction cardiomyopathy and a large secundum atrial septal defect (ASD) measuring 1.4 cm. Additionally, there was a haemodynamically significant left to right shunt causing acute decompensated systolic heart failure. She eventually underwent closure of the septal defect using a AMPLATZER Septal Occluder device. Decision to close the defect was made as the left to right shunt was causing severe pulmonary hypertension and acute heart failure. Since most heart failure treatments involve lowering of the LV afterload there was consideration that this could cause right to left shunting and could cause an Eisenmenger physiology. Hence the AMPLATZER Septal Occluder device was placed to eliminate the shunt through the ASD. The ASD combined with the non-compaction posed significant treatment challenge in this case.

Endocytosis is both an ancient and a diverse feature of the eukaryotic cell. Studying how it evolved can provide insight into the nature of the last common eukaryotic ancestor, and the diversification of eukaryotes into the known extant lineages. In this thesis, I present two studies on the evolution of endocytosis. In the first part of the thesis I report results from a large-scale, phylogenetic and comparative genomic study of clathrin-mediated endocytosis (CME). The CME pathway has been studied to a great level of detail in yeast to mammal model organisms. Several protein families have now been identified as part of the complex set of protein-protein and protein-lipid interactions which mediate endocytosis. To investigate how such complexity evolved, first, I defined the modular nature of the CME interactome (CME-I) by literature review, and then I carried out a systematic phylogenetic and protein domain architecture analysis of the proteins involved. These data were used to construct a model of the evolution of the CME-I network, and to map the expansion of the network's complexity to the eukaryotic tree of life. In the second part of the thesis, I present results from evolutionary and functional studies of the eisosome, a protein complex which has been proposed to regulate the spatial distribution of endocytosis in S. cerevisiae. The phylogeny of eisosomes components Pil1 and Lsp1 reported here, suggests that eisosomes are likely to have originated at the base of the fungi, and then diversified significantly via multiple gene duplications. I thus studied the localisation and function of Pil1 and Lsp1 homologues in Magnaporthe oryzae to investigate the role of eisosomes in filamentous fungi. Results suggests that eisosomes are linked with septal formation and integrity in M. oryzae, and that the septal specific Pil2 paralogue was lost in budding yeasts. Together, the data presented in this thesis describe the evolutionary history of a complex biological system, but also highlights the problem of asymmetry in the understanding of endocytic diversity in the eukaryotes.

Background: Coarctation of the aorta (CoA) is a congenital heart disease which represents a narrowing of the proximal descending aorta, hence increasing pressure afterload to the left ventricle (LV). Conventional treatment of native CoA is surgical repair, however potential recurrence or other related complications e.g. aortic rupture, heart failure and cerebrovascular events are common. Thus, lifelong follow-up of these patients is required. Echocardiography is the most patient’s friendly method to evaluate CoA and in particular its effect on LV function. Moreover, the novel speckle tracking echocardiography (STE) is an important method to assess subclinical LV dysfunction, a technique that promises better evaluation of LV function in these patients. The aims of this thesis were to review the literature on LV function in children with CoA using myocardial deformation imaging technologies, hence, to better understand the current knowledge and vagueness of the scientific evidence. We also aimed to study the effect of early CoA repair on the structure and function of LV and ascending aorta. In addition, we wished to establish in a meta-analysis format normal values of speckle tracking derived strain and strain rate values. Methods: Study 1. We have systematically searched the PubMed, and studies that fulfilled the inclusion criteria were critically analyzed and presented on a narrative form. Study 2 and 3. In addition to conventional echocardiographic measures of LV and ascending aorta, we measured longitudinal strain and strain rate of the LV using a vendor independent software, TomTec. We have also measured the aorto-septal angle (AoSA). Data was compared with normal healthy controls. Study 4. Electronic databases were systematically searched and suitable studies were meta analyzed using Comprehensive meta-analysis version 3 software. Results: Study 1. In 7/4945 included articles, 123 and 76 patients with congenital aortic stenosis (CAS) and CoA were reported, respectively. Normal conventional LV function, with subclinical myocardial dysfunction were reported in all studies before intervention. After intervention, a consistent improvement of myocardial deformation parameters was documented, even though not reaching normal values. Study 2. In 21 patients with CoA, LV function significantly improved after intervention (p &lt;0.001), however normal values were not reached even at medium-term follow-up (p = 0.002). Medium-term longitudinal strain correlated with pre intervention LV ejection faction (EF) (r = 0.58, p = 0.006). Medium-term subnormal values were more frequently associated with Bicuspid aortic valve (BAV) (33.3% vs. 66.6%; p &lt;0.05). Study 3. AoSA was abnormally wide before intervention, in particular at peak ejection in the descending aorta (p &lt;0.0001), and correlated with CoA pressure gradient. After intervention, AoSA normalized and significantly correlated with the increase of LV cavity function and overall LV deformation parameters. Study 4. In a meta-analysis of 28/282 studies including 1192 subjects, strain and strain rate values were established. Longitudinal strain normal mean values varied from -12.9 to -26.5 (mean, -20.5; 95 % CI, -20.0 to -21.0). Normal mean values of circumferential strain varied from -10.5 to -27.0 (mean, -22.06; 95 % CI, -21.5 to -22.5). Radial strain normal mean values varied from 24.9 to 62.1 (mean, 45.4; 95 % CI, 43.0 to 47.8). Meta-regression showed LV end-diastolic diameter as a significant determinant of variation of longitudinal strain. Longitudinal systolic strain rate was significantly determined by age and radial strain was influenced by the type of vendor used. Conclusion: The systematic review showed subclinical LV dysfunction in children with CoA before and after correction. However, since most of the patients were operated at an older age and had preserved LV EF, the effect of early intervention on LV function was only speculated. Our children with CoA who were operated at an earlier age showed LV subclinical dysfunction even at medium- term after intervention while the AoSA returned to normal shortly after intervention. Lower longitudinal strain values were found in patients with LV dysfunction (LV EF &lt;50%) before intervention and BAV. Finally, normal range values for strain and strain rate have been established and seem to be influenced by patients’ age, LV end-diastolic diameter and vendor used.

Doenças cardíacas congênitas são as mais frequentes entre as malformações congênitas graves, afetando de duas a três crianças por 100 nascidos vivos, sendo o defeito do septo atrioventricular (DSAV) responsável por 5% desses, e atingindo cerca de 50% dos pacientes portadores de Síndrome de Down. Caracteriza-se essencialmente por vários graus de desenvolvimento incompleto do tecido septal ao redor das valvas atrioventriculares, bem como de anormalidades na formação das mesmas. Recomenda-se a correção cirúrgica ao redor de 4 meses de vida, no intuito de prevenir o surgimento de hipertensão pulmonar (HP) irreversível devida ao hiperfluxo pulmonar, no entanto a despeito disso, identifica-se a presença de hipertensão pulmonar em pacientes já submetido ä correção do defeito cardíaco. O presente estudo teve por objetivo analisar a prevalência de hipertensão pulmonar diagnosticada através do ecocardiografia e identificar dos fatores de risco em pacientes submetidos à correção cirúrgica de DSAV nos últimos 16 anos no Hospital das Clínicas da Faculdade de Medicina de Ribeirão preto da Universidade de São Paulo (HCFMRP - USP). Foram selecionados pacientes portadores de DSAV, submetidos à correção cirúrgica no HCFMRP - USP, no período de janeiro de 1999 a janeiro de 2016, em seguimento no Ambulatório de Cardiologia Infantil do HCFMRP-USP, considerados portadores de hipertensão pulmonar os pacientes que apresentaram à ecocardiografia valores estimados de pressão sistólica de artéria pulmonar (PSAP) superiores a 30 mmHg. Foram analisadas variáveis clínicas pré e pós-operatórias. Não foi encontrada correlação entre peso e idade na data da correção cirúrgica e presença de HP na avaliação ecocardiográfica pós-operatória; no entanto esta se relacionou com tempo prolongado de circulação extra-corpórea e ventilação mecânica. Houve aumento significativo na sobrevida nos últimos oito anos analisados, refletindo a melhoria na qualidade de atendimento clinico e cirúrgico dos pacientes. A alta perda de seguimento ambulatorial causa preocupação, porém reflete as dificuldades próprias de serviços de saúde de países em desenvolvimento. / Congenital heart diseases are the most common serious congenital malformations, affecting two of three children per 100 newborns, the atrioventricular septal defect (AVSD) is responsible for 5% of these cases, reaching almost 50% of bearers of Down\'s Syndrome. It has been characterized essentially by many incomplete development degrees of de septal tissue around the atrioventricular valves, as well as its formation abnormalities. The actual recommendation is to proceed surgical correction nearly 4 months of age, in order to prevent irreversible pulmonary hypertension (PH) due to the pulmonary overflow. Despite of the surgical correction, patients may present pulmonary hypertension. This research aimed to analyze the prevalence of pulmonary hypertension diagnosed by transthoracic echocardiogram and identify risk factors for this outcome in patients undergoing surgical correction of AVSD in the last 16 years at the Hospital das Clínicas da Faculdade de Medicina de Ribeirão Preto da Universidade de São Paulo (HCFMRP - USP). All patients diagnosed with AVSD, submitted to surgical correction and followed at the HCFMRP - USP in the last 16 years and were selected. Those who had systolic pulmonary arterial pressure above 30 mmHg in the echocardiogram evaluation were considered to have pulmonary hypertension. Clinical variables before and after surgery were analyzed. Anthropometric and age data at the surgery had no influence in the presence of PH in the follow up. Although prolonged cardiopulmonary bypass and pulmonary mechanical ventilation had significantly affected that outcome. The survival had increased significantly in the last eight years of our study, reflecting the improvement of assistance. A high loss of follow up was detected and made us very concerned, however shows the difficulties and low investment in the public health system in developing countries.

Doenças cardíacas congênitas são as mais frequentes entre as malformações congênitas graves, afetando de duas a três crianças por 100 nascidos vivos, sendo o defeito do septo atrioventricular (DSAV) responsável por 5% desses, e atingindo cerca de 50% dos pacientes portadores de Síndrome de Down. Caracteriza-se essencialmente por vários graus de desenvolvimento incompleto do tecido septal ao redor das valvas atrioventriculares, bem como de anormalidades na formação das mesmas. Recomenda-se a correção cirúrgica ao redor de 4 meses de vida, no intuito de prevenir o surgimento de hipertensão pulmonar (HP) irreversível devida ao hiperfluxo pulmonar, no entanto a despeito disso, identifica-se a presença de hipertensão pulmonar em pacientes já submetido ä correção do defeito cardíaco. O presente estudo teve por objetivo analisar a prevalência de hipertensão pulmonar diagnosticada através do ecocardiografia e identificar dos fatores de risco em pacientes submetidos à correção cirúrgica de DSAV nos últimos 16 anos no Hospital das Clínicas da Faculdade de Medicina de Ribeirão preto da Universidade de São Paulo (HCFMRP - USP). Foram selecionados pacientes portadores de DSAV, submetidos à correção cirúrgica no HCFMRP - USP, no período de janeiro de 1999 a janeiro de 2016, em seguimento no Ambulatório de Cardiologia Infantil do HCFMRP-USP, considerados portadores de hipertensão pulmonar os pacientes que apresentaram à ecocardiografia valores estimados de pressão sistólica de artéria pulmonar (PSAP) superiores a 30 mmHg. Foram analisadas variáveis clínicas pré e pós-operatórias. Não foi encontrada correlação entre peso e idade na data da correção cirúrgica e presença de HP na avaliação ecocardiográfica pós-operatória; no entanto esta se relacionou com tempo prolongado de circulação extra-corpórea e ventilação mecânica. Houve aumento significativo na sobrevida nos últimos oito anos analisados, refletindo a melhoria na qualidade de atendimento clinico e cirúrgico dos pacientes. A alta perda de seguimento ambulatorial causa preocupação, porém reflete as dificuldades próprias de serviços de saúde de países em desenvolvimento. / Congenital heart diseases are the most common serious congenital malformations, affecting two of three children per 100 newborns, the atrioventricular septal defect (AVSD) is responsible for 5% of these cases, reaching almost 50% of bearers of Down\'s Syndrome. It has been characterized essentially by many incomplete development degrees of de septal tissue around the atrioventricular valves, as well as its formation abnormalities. The actual recommendation is to proceed surgical correction nearly 4 months of age, in order to prevent irreversible pulmonary hypertension (PH) due to the pulmonary overflow. Despite of the surgical correction, patients may present pulmonary hypertension. This research aimed to analyze the prevalence of pulmonary hypertension diagnosed by transthoracic echocardiogram and identify risk factors for this outcome in patients undergoing surgical correction of AVSD in the last 16 years at the Hospital das Clínicas da Faculdade de Medicina de Ribeirão Preto da Universidade de São Paulo (HCFMRP - USP). All patients diagnosed with AVSD, submitted to surgical correction and followed at the HCFMRP - USP in the last 16 years and were selected. Those who had systolic pulmonary arterial pressure above 30 mmHg in the echocardiogram evaluation were considered to have pulmonary hypertension. Clinical variables before and after surgery were analyzed. Anthropometric and age data at the surgery had no influence in the presence of PH in the follow up. Although prolonged cardiopulmonary bypass and pulmonary mechanical ventilation had significantly affected that outcome. The survival had increased significantly in the last eight years of our study, reflecting the improvement of assistance. A high loss of follow up was detected and made us very concerned, however shows the difficulties and low investment in the public health system in developing countries.

INTRODUCAO: A comunicação interatrial tipo \"ostium secundum\" é um defeito cardíaco congênito caracterizado pela deficiência parcial ou total da lâmina da fossa oval, também chamada de septo primo. Corresponde a 10 a 12% do total de cardiopatias congênitas, sendo a mais frequente na idade adulta. Atualmente a oclusão percutânea é o método terapêutico de escolha em defeitos com características anatômicas favoráveis para o implante de próteses na maioria dos grandes centros mundiais. A ecocardiografia transesofágica bidimensional com mapeamento de fluxo em cores é considerada a ferramenta padrão-ouro para a avaliação anatômica e monitoração durante do procedimento, sendo crucial para a ótima seleção do dispositivo. Neste sentido, um balão medidor é introduzido e insuflado através do defeito de forma a ocluí-lo temporariamente. A medida da cintura que se visualiza no balão (diâmetro estirado) é utilizada como referência para a escolha do tamanho da prótese. Recentemente a ecocardiografia tridimensional transesofágica em tempo real tem sido utilizada neste tipo de intervenção percutânea. Neste estudo avaliamos o papel da mesma na ótima seleção do dispositivo levando-se em consideração as dimensões e a geometria do defeito e a espessura das bordas do septo interatrial. METODO: Estudo observacional, prospectivo, não randomizado, de único braço, de uma coorte de 33 pacientes adultos portadores de comunicação interatrial submetidos a fechamento percutâneo utilizando dispositivo de nitinol autocentrável (Cera ®, Lifetech Scientific, Shenzhen, China). Foram analisadas as medidas do maior e menor diâmetro do defeito, sua área e as medidas do diâmetro estirado com balão medidor obtidas por meio das duas modalidades ecocardiográficas. Os defeitos foram considerados como elípticos ou circulares segundo a sua geometria; as bordas ao redor da comunicação foram consideradas espessas (>2 mm) ou finas. O dispositivo selecionado foi igual ou ate 2 mm maior que o diâmetro estirado na ecocardiografia transesofágica bidimensional (padrão-ouro). Na tentativa de identificar uma variável que pudesse substituir o diâmetro estirado do balão para a ótima escolha do dispositivo uma série de correlações lineares foram realizadas. RESULTADOS: A idade e peso médio foram de 42,1 ± 14,9 anos e 66,0 ± 9,4kg, respectivamente; sendo 22 de sexo feminino. Não houve diferenças estatísticas entre os diâmetros maior e menor ou no diâmetro estirado dos defeitos determinados por ambas as modalidades ecocardiográficas. A correlação entre as medidas obtidas com ambos os métodos foi ótima (r > 0,90). O maior diâmetro do defeito, obtido à ecoardiografia transesofágica tridimensional, foi a variável com melhor correlação com o tamanho do dispositivo selecionado no grupo como um todo (r= 0,89) e, especialmente, nos subgrupos com geometria elíptica (r= 0,96) e com bordas espessas ao redor do defeito (r= 0,96). CONCLUSÃO: Neste estudo em adultos com comunicações interatriais tipo ostium secundum submetidos à oclusão percutânea com a prótese Cera ®, a ótima seleção do dispositivo pôde ser realizada utilizando-se apenas a maior medida do defeito obtida na ecocardiografia transesofágica tridimensional em tempo real, especialmente nos pacientes com defeitos elípticos e com bordas espessas. / INTRODUCTION: The ostium secundum atrial septal defect is a congenital heart disease characterized by partial or total deficiency of the fossa ovalis, also known as the septum primum. It corresponds to 10-12% of all congenital heart defects, being the most frequently found in adulthood. Currently, percutaneous closure is the therapeutic method of choice for defects with suitable anatomic features for device implantation in most centers in the world. Bi-dimensional transesophageal echocardiography with color flow mapping is considered the gold-standard tool for anatomic assessment and procedural monitoring, being crucial for optimal device selection. In this regard, a sizing balloon is introduced and inflated across the defect with temporary occlusion. The waist measurement seen on the balloon (stretched diameter) is used as a reference for selection of device size. Recently, real time three-dimensional transesophageal echocardiography has been utilized in this type of percutaneous intervention. In this study we assessed the role of this modality in optimal device selection taking into consideration the dimensions and the geometry of the defect and the thickness of the interatrial septum rims. METHODS: Observational, prospective, non-randomized, single-arm study of a cohort of 33 adults with atrial septal defects submitted to percutaneous closure using a self-centered nitinol device (Cera (TM), Lifetech Scientific, Shenzhen, China). The largest and the smallest diameter of the defect, its area and the measurements of the stretched diameter of the sizing balloon were assessed by both echocardiographic modalities. The defects were considered as elliptical or circular according to their geometry; the rims surrounding the defect were considered thick (> 2 mm) or thin. The selected device was equal to or 2 mm larger than the stretched diameter on bi-dimensional transesophageal echocardiography (gold-standard). In an attempt to identify a variable that could replace the stretched balloon diameter, a series of linear correlations were performed. RESULTS: The mean age and weight were 42.1 ± 14.9 years and 66.0 ± 9.4 kgs, respectively; being 22 of the female gender. There were no statistical differences between the largest and smallest diameters of the defects and the stretched diameters determined by both echocardiographic modalities. The correlation between the measurements obtained by both methods was excellent (r > 0.90). The largest defect diameter obtained by three-dimensional transesophageal echocardiography was the variable that showed the best correlation with the selected device size in the entire group (r= 0.89), especially in the subgroups with elliptical geometry (r= 0.96) and with thick rims surrounding the defect (r=0.96). CONCLUSIONS: In this study in adults with ostium secundum atrial septal defects submitted to percutaneous occlusion with the Cera (TM) device, optimal device selection could be performed using solely the largest diameter of the defect obtained by real time three-dimensional transesophageal echocardiography, especially in patients with elliptical defects and thick rims.