Os objetivos do estudo foram avaliar as características clínicas das embolias arteriais sistêmicas no curso da endocardite infecciosa, a distribuição temporal, os fatores de risco de embolia e a influência prognóstica da embolia no curso da doença. Foram estudados 629 episódios de endocardite infecciosa. A idade dos pacientes variou de 2 meses a 83 anos (média 37,9 anos; desvio padrão 17,3). Ocorreram 396 (63%) episódios em homens e 233 (47%) em mulheres. Em 538 (85%) episódios, os pacientes eram portadores de doença cardíaca prévia, 272 (43%) com valvopatia, 224 (36%) portadores de prótese valvar cardíaca, 29 (5%) com doença cardíaca congênita, 13 (2%) com outras cardiopatias e 91 (14%) pacientes não apresentavam evidência de cardiopatia prévia. Os agentes etiológicos foram os estreptococos em 297 (47%) pacientes, os enterococos em 51 (8%), os Staphylococcus aureus em 77 (12,6%), os Staphylococcus epidermidis em 56 (9%), as bactérias gram-negativas em 33 (5%), os fungos em nove (1,4%), e outros microorganismos em 27 (4%). Em 79 (13%) pacientes as hemoculturas foram negativas. Os pacientes receberam tratamento clínico em 376 (60%) episódios e cirúrgico em 253 (40%). Para a análise estatística foram utilizados além da estatística descritiva, o método de Kaplan-Meier para avaliar a sobrevida livre de embolia e o prognóstico, comparadas com os testes de Log-rank e Breslow. Em seguida para a estimativa de riscos, foi ajustado o modelo de riscos proporcionais de Cox. As embolias arteriais ocorreram em 133 (21%) pacientes, cerebrais em 63 (47%), extracerebrais em 57 (43%) e cerebrais a extracerebrais em 13 (10%) pacientes. A distribuição temporal das embolias foi decrescente após o início dos sintomas. O risco de embolia não revelou diferença significativa quanto a idade, a sexo, o estado cardíaco, presença e número de vegetações identificadas no ecocardiograma e a modalidade de tratamento clínico ou cirúrgico. Os pacientes com endocardite causada por Staphylococcus aureus apresentaram risco de ocorrência de embolia 2,9 vezes maior do que os pacientes com endocardite causada por outros agentes etiológicos. Nos pacientes com endocardite infecciosa em prótese mitral e aórtica com vegetação identificada no ecocardiograma, o risco de embolia foi respectivamente 2,4 e 3,3 vezes maior relação aos pacientes com endocardite em valva natural ou em prótese sem vegetação. O risco de embolia foi menor a medida que o tempo decorrido entre o início dos sintomas e o tratamento aumentou. O risco de óbito nos pacientes que sofreram embolia duplicou em relação aos pacientes que não sofreram embolia. / The objectives of the study were to evaluate the clinical characteristics of systemic arterial embolism at infective endocarditis courses, the time related distribution of emboli, risk predictors and prognostic influence of emboli during active disease. So far, we studied 629 episodes of left-sided endocarditis. The patients were aged 37.9 ± 17.3 years; 396 (63%) episodes occurred in men; 233 (47%) in women; 538 (85%) episodes occurred in patients with heart disease: 272 (43%) had valvular heart disease, 224 (36%) had prosthetic heart valves, 29 (5%) had congenital heart disease, 13 (2%) had others cardiac diseases and 91 (14%) had no known heart disease. The causative microorganisms were streptococci in 297 (47%) patients, enterococci in 51 (8%), Staphylococcus aureus in 77 (1 2.6%), Sfaphylococcus epidermidis in 56 (9%), gram-negative bacteria in 33 (5%), fungi in nine (1.4%), and other microorganisms in 27 (4%); 79 (13%) patients had negative blood cultures. The treatment was medical in 376 (60%) and surgical in 253 (40%) episodes. Statistical analysis was pet-formed with descriptive analysis, with Kaplan-Meier methods to evaluate survival free of emboli and prognosis, and Cox proportional hazards model for risk analysis; 133 (21%) patients had an embolic event; 63 (47%) were cerebral emboli and 57 (43%) were extracerebral emboli and 13 (10%) were cerebral and extracerebral. The time-related distribution showed decrease in the incidence after beginning of symptoms. The risk for emboli was not significantly different relative to age, sex, cardiac status, presence or number of vegetations at echocardiogram, and medical or surgical treatment. The risk of emboli was 2.97 times higher in patients with Staphylacoccus aureus endocarditis. The risk of embolism in patients with infective endocarditis in mitral and aortic prosthetic valve with vegetations were 2.4 and 3.3 times higher. The risk of embolism decrease as the time elapsed between beginning of symptoms and treatment increased, suggesting a lower risk in less acute disease. Risk of death was 2.01 times higher in patients with embolism.

Diss. (sammanfattning) Stockholm : Karolinska institutet, 2005. / Härtill 4 uppsatser.

Os objetivos do estudo foram avaliar as características clínicas das embolias arteriais sistêmicas no curso da endocardite infecciosa, a distribuição temporal, os fatores de risco de embolia e a influência prognóstica da embolia no curso da doença. Foram estudados 629 episódios de endocardite infecciosa. A idade dos pacientes variou de 2 meses a 83 anos (média 37,9 anos; desvio padrão 17,3). Ocorreram 396 (63%) episódios em homens e 233 (47%) em mulheres. Em 538 (85%) episódios, os pacientes eram portadores de doença cardíaca prévia, 272 (43%) com valvopatia, 224 (36%) portadores de prótese valvar cardíaca, 29 (5%) com doença cardíaca congênita, 13 (2%) com outras cardiopatias e 91 (14%) pacientes não apresentavam evidência de cardiopatia prévia. Os agentes etiológicos foram os estreptococos em 297 (47%) pacientes, os enterococos em 51 (8%), os Staphylococcus aureus em 77 (12,6%), os Staphylococcus epidermidis em 56 (9%), as bactérias gram-negativas em 33 (5%), os fungos em nove (1,4%), e outros microorganismos em 27 (4%). Em 79 (13%) pacientes as hemoculturas foram negativas. Os pacientes receberam tratamento clínico em 376 (60%) episódios e cirúrgico em 253 (40%). Para a análise estatística foram utilizados além da estatística descritiva, o método de Kaplan-Meier para avaliar a sobrevida livre de embolia e o prognóstico, comparadas com os testes de Log-rank e Breslow. Em seguida para a estimativa de riscos, foi ajustado o modelo de riscos proporcionais de Cox. As embolias arteriais ocorreram em 133 (21%) pacientes, cerebrais em 63 (47%), extracerebrais em 57 (43%) e cerebrais a extracerebrais em 13 (10%) pacientes. A distribuição temporal das embolias foi decrescente após o início dos sintomas. O risco de embolia não revelou diferença significativa quanto a idade, a sexo, o estado cardíaco, presença e número de vegetações identificadas no ecocardiograma e a modalidade de tratamento clínico ou cirúrgico. Os pacientes com endocardite causada por Staphylococcus aureus apresentaram risco de ocorrência de embolia 2,9 vezes maior do que os pacientes com endocardite causada por outros agentes etiológicos. Nos pacientes com endocardite infecciosa em prótese mitral e aórtica com vegetação identificada no ecocardiograma, o risco de embolia foi respectivamente 2,4 e 3,3 vezes maior relação aos pacientes com endocardite em valva natural ou em prótese sem vegetação. O risco de embolia foi menor a medida que o tempo decorrido entre o início dos sintomas e o tratamento aumentou. O risco de óbito nos pacientes que sofreram embolia duplicou em relação aos pacientes que não sofreram embolia. / The objectives of the study were to evaluate the clinical characteristics of systemic arterial embolism at infective endocarditis courses, the time related distribution of emboli, risk predictors and prognostic influence of emboli during active disease. So far, we studied 629 episodes of left-sided endocarditis. The patients were aged 37.9 ± 17.3 years; 396 (63%) episodes occurred in men; 233 (47%) in women; 538 (85%) episodes occurred in patients with heart disease: 272 (43%) had valvular heart disease, 224 (36%) had prosthetic heart valves, 29 (5%) had congenital heart disease, 13 (2%) had others cardiac diseases and 91 (14%) had no known heart disease. The causative microorganisms were streptococci in 297 (47%) patients, enterococci in 51 (8%), Staphylococcus aureus in 77 (1 2.6%), Sfaphylococcus epidermidis in 56 (9%), gram-negative bacteria in 33 (5%), fungi in nine (1.4%), and other microorganisms in 27 (4%); 79 (13%) patients had negative blood cultures. The treatment was medical in 376 (60%) and surgical in 253 (40%) episodes. Statistical analysis was pet-formed with descriptive analysis, with Kaplan-Meier methods to evaluate survival free of emboli and prognosis, and Cox proportional hazards model for risk analysis; 133 (21%) patients had an embolic event; 63 (47%) were cerebral emboli and 57 (43%) were extracerebral emboli and 13 (10%) were cerebral and extracerebral. The time-related distribution showed decrease in the incidence after beginning of symptoms. The risk for emboli was not significantly different relative to age, sex, cardiac status, presence or number of vegetations at echocardiogram, and medical or surgical treatment. The risk of emboli was 2.97 times higher in patients with Staphylacoccus aureus endocarditis. The risk of embolism in patients with infective endocarditis in mitral and aortic prosthetic valve with vegetations were 2.4 and 3.3 times higher. The risk of embolism decrease as the time elapsed between beginning of symptoms and treatment increased, suggesting a lower risk in less acute disease. Risk of death was 2.01 times higher in patients with embolism.

Streptococcus sanguinis is the second most common causative agent of bacterial infective endocarditis (IE). Risk of S. sanguinis IE is dependent on pre-disposing damage to the heart valve endothelium, which results in deposition of clotting factors for formation of a sterile thrombus (referred to as vegetation). Despite medical advances, high mortality and morbidity rates persist. Molecular characterization of S. sanguinis virulence determinants may enable development of prevention methods. In a previous screen for S. sanguinis virulence determinants by signature-tagged mutagenesis (STM) an attenuated mutant was identified with a transposon insertion in the nrdD gene, encoding an anaerobic ribonucleotide reductase. Evaluation of this mutant, as well as an nrdD in-frame deletion mutant, JFP27, by a soft-agar growth assay confirmed the anaerobic growth sensitivity of these strains. These studies suggest that an oxygen gradient occurs at the site of infection which selects for expression of anaerobic-specific genes at the nexus of the vegetation. The random STM screen failed to identify any favorable streptococcal surface-exposed prophylactic candidates. It was also apparent that additional genetic tools were required to facilitate the in vivo analyses of mutant strains. As it was desirable to insert antibiotic resistance markers into the chromosome, we identified a chromosomal site for ectopic expression of foreign genes. In vitro and in vivo analyses verified that insertion into this site did not affect important cellular phenotypes. The genetic tools developed facilitated further in vivo screening of S. sanguinis cell wall-associated (Cwa) protein mutants. A directed application of STM was employed for a comprehensive analysis of this surface protein class in the rabbit model of IE. Putative sortases, upon which Cwa proteins are dependent for cell surface localization, were also evaluated. No single S. sanguinis Cwa protein was determined essential for IE by STM screening; however competitiveness for colonization of the infection site was reduced for the mutant lacking expression of sortase A. The studies described here present a progressive picture of S. sanguinis IE, beginning with surface protein-dependent colonization of the vegetation in early IE, that later shifts to a bacterial persistence in situ dependent on condition-specific housekeeping genes, including nrdD.

Biofilm accounts for 65%-80% of microbial infections in humans. Considerable evidence links biofilm formation to oral disease and consequently systemic infections. Eradication of biofilm-associated infections is important. Streptococcus sanguinis, a Gram-positive bacterium, is one of the most abundant species in oral biofilm. It contributes to biofilm development in oral cavities and is one of the recognized causes of infective endocarditis. To study and identify biofilm genes in S. sanguinis, biofilm formation of 51 mutants was compared with the wild type SK36 strain using crystal violet (CV) staining in a microtiter plate. Confocal laser scanning microscopy (CLSM) and image analysis was done to compare biofilm formation by the mutant to the wild type SK36 strain. A biofilm mutant XG2_0351, encoding a type I signal peptidase (SPase I), was further investigated. SPase I cleaves proteins that are transported through secretory machinery and is necessary for the release of translocated preproteins from a cytoplasmic site of synthesis to extracytoplasmic/membrane destinations. S. sanguinis, like many Gram-positive bacteria, has multiple SPases I. The objective of this project is to investigate the distinctive role that SPase I plays in biofilm formation in S. sanguinis. Using a plate reader, the growth curves of the wild type strain SK36 and XG2_0351 were compared. The scanning electron microscope (SEM) was utilized to compare the cell surface morphologies. Coomassie staining was done to narrow the list of potential substrates of XG2_0351. CV staining and CLSM images indicated phenotypic differences between the SPase I mutant and SK36. The growth curves of XG2_0351 and SK36 showed no significant difference although SEM illustrated a difference in the cell surface morphologies. Coomassie staining illustrated a number of substrates that were present in SK36 but not XG2_0351. In addition bioinformatics was used to understand the gene function. In conclusion, XG2_0351 reduces biofilm formation in S. sanguinis but further research is necessary to elucidate the specific proteins that are involved. Clarifying the vii role that SPase I plays in reduced biofilm formation in S. sanguinis will give a better understanding of the biofilm formation mechanism.

Les macrophages sont fonctionnellement polarisés en macrophages inflammatoires et microbicides (M1) ou immunorégulateurs (M2). Que les monocytes circulants soient polarisables n’est pas démontré. Nous avons étudié la signature transcriptionnelle par microarray et RT-PCR en temps réel de monocytes humains stimulés par l’IFN-γ, un inducteur des macrophages M1 et l’IL-4, un inducteur des macrophages M2. Leur profil de réponse précoce est dépendent de l’agoniste alors que la réponse tardive des monocytes est similaire qu’ils soient stimulés par l’IFN-γ ou l’IL-4. Cette approche dynamique de la réponse monocytaire permet probablement une étude bien plus pertinente des patients atteints d’une fièvre Q que le modèle de polarisation macrophagique. Par ailleurs, la prévalence de la fièvre Q est plus importante chez l’homme que chez la femme. Comme il a été montré que des gènes associés au cycle circadien sont modulés chez les souris infectées par Coxiella burnetii, la bactérie responsable de la fièvre Q, nous avons étudié ces gènes au cours de la fièvre Q. C’est ainsi que le gène Per2 est fortement exprimé chez les hommes atteints d’une fièvre Q aiguë. Ces résultats suggèrent donc que la modulation de gènes circadiens est associée à une maladie infectieuse chez l’homme. L’expression des gènes LNX1 and LNX2, qui codent deux enzymes impliquées dans le catabolisme des protéines, est accrue dans l’endocardite de la fièvre Q mais pas dans la fièvre Q aiguë. / Macrophages are functionally polarized into inflammatory and microbicidal (M1) and immunoregulatory (M2) cells. If circulating monocytes may be polarized is not known. We determined the transcriptional signatures of human monocytes stimulated with IFN-γ and IL-4, known to induce the polarization of macrophages into M1 and M2 cells, respectively, using microarrays and real-time RT-PCR. We found that monocytes exhibited an early pattern of activation specific to IFN-γ or IL-4 and a late pattern of activation common to both agonists. The selected biomarkers of early and late responses were tested in patients with Q fever. We showed that the kinetic model of monocyte activation enables a dynamic approach for the evaluation of patients with acute Q fever or Q fever endocarditis. On the other hand, it is known that the prevalence of Q fever is related to sex and is higher in men than in women. Based on previous studies on an experimental model of infection by Coxiella burnetii, the agent of Q fever, we hypothesized that circadian genes are differently modulated in men and women with Q fever. We showed that the expression of the Per2 gene was significantly increased in males with acute Q fever compared with healthy volunteers but did not differ in females with Q fever and healthy females. These results suggest that that the modulation of circadian genes is associated with a human infectious disease. We also found that the expression of LNX1 and LNX2 genes that encode two enzymes involved in protein degradation is increased in Q fever endocarditis but not in acute Q fever.

Staphylococcus aureus is defined by its ability to agglutinate during exposure to human blood plasma. Although agglutination has long correlated with disease severity, the function of agglutination during infection remains unclear. Increasing evidence suggests the mechanisms of agglutination are highly complex and poorly understood. The goal of this dissertation was to characterize the mechanisms required for S. aureus agglutination in vitro and determine how these factors contribute to pathogenesis. Chapter II focuses on the development of two in vitro agglutination assays, which allow the process to be measured quantitatively. Through these assays, we confirmed the major factors contributing to agglutination are human fibrinogen and the bacterial surface protein, ClfA. Productive interactions between these two factors are required for agglutination to proceed. Surprisingly, we also identified a novel regulatory system that significantly contributed to agglutination. Inactivation of the ArlRS two-component system (TCS) prevents agglutination in both of the developed assays. Studies in Chapter III focused on characterizing the mechanism by which ArlRS inhibits agglutination. To examine regulation, quantitative PCR identified the major output of the ArlRS system as the gene ebh. Surprisingly, transcript levels of known extracellular matrix (ECM) binding proteins did not change. Characterization of ebh indicated that overexpression in an arlRS mutant is the major factor responsible for preventing agglutination. Deletion of ebh restores the ability of the arlRS mutant to agglutinate in both gravity and flow-based agglutination assays. Fluorescence microscopy of clumps indicates wildtype cells bind and incorporate fluorescently labeled human fibrinogen (Fg) displaying co-localization with the clumps. Surprisingly, arlRS mutants also bound human Fg, but these interactions were not productive for clumping, suggesting successful agglutination is more complex than binding ECM proteins. These studies indicate that ArlRS regulates agglutination through a unique mechanism that depends on the surface protein Ebh. Studies in Chapter IV were performed to determine the role ArlRS played in pathogenesis. A rabbit model of infective endocarditis and sepsis was employed to assess ArlRS virulence because this model has been shown to require agglutination for disease progression. Mutants in arlRS displayed reduced virulence in the rabbit model of infective endocarditis, which correlated with the mutant's inability to form a vegetation of the heart valve. These studies provide further insight into the importance of S. aureus agglutination during infection and define a mechanism of regulation through a novel surface protein.

Staphylococcus aureus is a gram positive bacterium asymptomatically colonizing 30-40% of the human population. S. aureus causes a variety of infections including superficial skin lesions, toxic shock syndrome, and infective endocarditis (IE). There are 100,000 cases of IE each year in the United States. IE is a life threatening infection of native/prosthetic valves and the lining of the heart. It is characterized by the formation of vegetations, “cauliflower-like” structures composed of bacteria and host factors. S. aureus is the most commonly identified pathogen (up to 40%) in patients with IE. USA200 (Clonal Complex 30) strains of S. aureus are significantly associated with IE, all of which produce toxic shock syndrome toxin-1 (TSST-1) and β-toxin. TSST-1 characterizes the staphylococcal Group I superantigens (SAgs). The major mechanism of activity of TSST-1 and other SAgs is the ability to activate T-cells and APCs by non-specifically cross-bridging Vβ-chains of T-cell receptors (TCRs) with α and/or β-chains of major histocompatibility complex II (MHCII) molecules on antigen presenting cells (APCs). In a rabbit model of IE and sepsis, TSST-1 is critical for the development of vegetations and the associated colony forming units (CFUs). β-toxin has a molecular mass of 35 kDa, a basic pI (>10.0), and is a member of the DNase I superfamily. This cytotoxin has two distinct mechanisms of action: sphingomyelinase (SMase) activity and DNA biofilm ligase activity. β-toxin is critical for causing IE in a rabbit model that strongly resembles human disease. This toxin association had been observed, but studies have not been completed to determine what role TSST-1 and β-toxin play independently and in cooperation with one another, and more specifically which mechanism each uses, during IE infections. While TSST-1 and β-toxin are both important for IE, they are very different toxins. My studies determined that the presence of TSST-1 and β-toxin in combination results in the highest levels of lethality in a rabbit model of IE. A strain expressing TSST-1 lacking superantigenic activity has decreased lethality compared to the same strain expressing wild type TSST-1. My study is the first to begin characterization of the DNA biofilm ligase active site by identifying important residues via a DNA binding and biofilm formation assays. Furthermore, my research shows that a β-toxin mutant lacking SMase activity is decreased in lethality and vegetation formation compared to wild type. β-toxin mutants disrupted in biofilm ligase activity do not decrease lethality but are deficient in vegetation formation compared to wild type. Utilizing in vitro assays to assess cellular events during IE, I established that β-toxin causes changes to morphology and is cytotoxic to human aortic endothelial cells (HAECs), inhibits production of IL-8, and modulates the expression levels of cluster of differentiation 40 (CD40) and vascular cell adhesion molecule 1 (VCAM-1). My work shows these two virulence factors (TSST-1 and β-toxin) produced by USA200 strains and other clonal groups play important roles in causing IE.

Streptococcus gordonii is a primary coloniser of the tooth surface where it efficiently ferments carbohydrates at pH levels above 6.0. By not being able to maintain the pH of dental plaque to a level required for enamel dissolution, the dominance of S. gordonii in dental plaque is considered a sign of a healthy oral cavity. However, upon entering the bloodstream and encountering a rise in pH, S. gordonii may become pathogenic, being one of the major causative organisms associated with infective endocarditis. Proteome analyses of S. gordonii grown at steady state in a chemostat allowed the phenotypic changes associated with alterations in pH levels characteristic of these two environments to be determined. As an initial starting point to this study, a two-dimensional electrophoresis (2- DE) reference map of S. gordonii grown at pH 7.0 was produced. Although only 50% of the S gordonii genome was available in an annotated form during the course of this study, the closely related Streptococcus pneumoniae genome (with which S. gordonii shares 97.24% DNA sequence homology) had been completed in 2001. The use of both of these databases allowed many of the S. gordonii proteins to be identified by mass spectrometry. Four hundred and seventy six protein spots, corresponding to 250 different proteins, or 12.5% of the S. gordonii proteome, were identified, giving rise to the first comprehensive proteome reference map of this oral bacterium. Of the 250 different proteins, 196 were of cellular origin while 68 were identified from the extracellular milieu. Only 14 proteins were common to both compartments. Of particular interest among the 54 uniquely identified extracellular proteins was a homologue of a peptidoglycan hydrolase that has been associated with virulence in S. pneumoniae. Among the other proteins identified were ones involved in transport and binding, energy metabolism, translation, transformation, stress response and virulence. Twelve cell envelope proteins were identified as well as 25 others that were predicted to have a membrane association based on the presence of at least one transmembrane domain. The study also confirmed the existence of 38 proteins previously designated as �hypothetical� or with no known function. Mass spectral data for over 1000 protein spots were accumulated and archived for future analysis when sequencing of the S. gordonii genome is finally completed. Following the mapping of the proteome of S. gordonii, alterations in protein spots associated with growth of the bacterium at pH intervals of 0.5 units in the pH range 5.5 - 7.5 were determined. Only 16 protein spots were shown to be significantly altered in their level of expression despite the range of pH studied. Among the differentially expressed proteins was a manganese-dependent inorganic pyrophosphatase (PpaC), which regulates expression of adhesins required for coaggregation. The expression of PpaC was highest at pH 6.5 - 7.0, the pH of a healthy oral cavity, indicating that PpaC may play an important part in dental plaque formation. Another differentially expressed protein was the heat-inducible transcription repressor (HrcA). Alterations in HrcA were consistent with its role as a negative repressor in regulating heat-shock proteins at low pH, even though no changes in the level of heat-shock proteins were observed as the pH declined. This result gave rise to the hypothesis that the possible reason cariogenic bacteria, such as Streptococcus mutans, can out compete S. gordonii at low pH might simply be due to their ability to manipulate their proteome in a complex manner for survival and persistence at low pH, unlike S. gordonii. This may imply some prevailing level of genetic regulation that is missing in S. gordonii.

Barcelona : Impr. universal de Juan Bautista Llop, 1893 / “En el estudio de las ciencias biológicas, como en el de las eminentemente prácticas, debe de relegarse á un lugar muy secundario y sospechoso todo cuanto no sea hijo legítimo de la más concienzuda experimentación (…) Cualquiera cuestión técnica expuesta en el seno de las doctas corporaciones, como cualquier hecho insólito de carácter epidémico que azote á las multitudes, es pretexto abonado para suscitar debates y pareceres, que se caracterizarán, no por tener una misma unidad de miras, no por correr parejas con un racional criterio, pero sí por ser tantos en número cuantas sean las individualidades lanzadas impremeditadamente al palenque. Que los médicos tengan opiniones, es muy natural y viejo; que ellas son múltiples y exajeradas, tampoco es nuevo; pero que sean encontradas y en su mayoría opuestas, es cosa muy lamentable. El médico joven que consagra toda su atención a los problemas científicos, hasta el punto de convertirse en su propio esclavo, cae en un mar de confusiones siempre que aquéllos se refieren á casos por él no vistos ni comprobados en las salas del Hospital; las mil y una soluciones que á dichos problemas se dan, acaban por trocar su entusiasmo científico por el más cruel de los excepticismos (…)Para no concurrir, pues, con un nuevo grano de arena á engrosar esos inconmensurables obstáculos, y para no incurrir en el delito de una innovación no consolidada por los méritos que son menester, nos decidimos á desenvolver nuestro trabajo reglamentario bajo un tema que podrá no suscitar grandes polémicas, ni predisponer á la divagación de ideas, no ser pródigo en emociones y sorpresas, pero cuya capitalísima y escepcional importancia tiene en su favor los sufragios de aquellos á quienes no se les oculta la gran utilidad que á muchos prácticos pudiera reportar una recopilación de las endocarditis crónicas en un solo capítulo, redactado con estilo sencillo, dispuesto con un plan y método lo más claros posible, consagrado sólo á lo decisivo y concluyente, y ajeno á los detalles supérfluos y á las ampulosidades de relumbrón, que siempre han de redundar en menoscabo de la sencillez, concisión y claridad de que tanto necesitan las cuestiones teórico-prácticas, Esto es lo que nosotros nos hemos propuesto; pero ¿nos ha sido dable conseguirlo en todos sus puntos? Juzgue y dígalo el doctísimo cuanto respetable tribunal”.