The effect of age and sex on the diagnostic yield of the echocardiogram in patients with syncope.

INTRODUCTION: Syncope is the motivation for numerous diagnostic tests, among them transthoracic echocardiography (TTE); however, previous evidence suggests there is little utility in this test. Our objective was to assess its diagnostic yield in syncope, analysing the effect of age and sex. MATERIAL AND METHODS: We conducted an observational study that included patients with syncope and who underwent TTE between 1990 and 2015. We defined diagnostic findings related to syncope and performed a descriptive analysis, assessing the diagnostic yield (overall and according to age and sex). RESULTS: The study included 3302 patients and measured a diagnostic yield of 8.8%; the most common finding was ventricular dysfunction (4.5%). The probability of a diagnostic TTE significantly increased with age (p<.001) but was low for patients younger than 50 years (2.3%). The male sex was significantly related with a diagnostic TTE (p<.001), mostly due to the higher rate of ventricular dysfunction. CONCLUSIONS: The diagnostic yield of TTE in patients with syncope is moderate, low in patients younger than 50 years and lower in women than in men. These factors should be considered when conducting a diagnostic study of patients with syncope.

Efecto de la edad y el sexo en el rendimiento diagnóstico del ecocardiograma en pacientes con síncope / The effect of age and sex on the diagnostic yield of the echocardiogram in patients with syncope

Introducción El síncope es motivo de numerosas pruebas diagnósticas, entre las que está el ecocardiograma transtorácico (ETT). Existe evidencia previa que sugiere escasa utilidad de esta prueba. Nuestro objetivo fue evaluar su rendimiento diagnóstico en el síncope, analizando el efecto de la edad y el sexo. Materiales y métodos Estudio observacional en el que se incluyeron pacientes con síncope y ETT entre 1990 y 2015. Se definieron hallazgos diagnósticos relacionados con el síncope. Realizamos un análisis descriptivo evaluando el rendimiento diagnóstico en global, y en función de edad y sexo. Resultados Se incluyeron 3.302 pacientes, siendo el rendimiento diagnóstico del 8,8%; el hallazgo más frecuente fue disfunción ventricular (4,5%). La probabilidad de ETT diagnóstico aumentó significativamente con la edad (p<0,001), siendo baja en menores de 50 años (2,3%). El sexo masculino se relacionó significativamente con ETT diagnóstico (p<0,001), a expensas de mayor frecuencia de disfunción ventricular. Conclusiones El rendimiento diagnóstico del ETT en pacientes con síncope es moderado, siendo bajo en edades inferiores a 50 años, y menor en mujeres que en hombres. Estos factores deben ser tenidos en cuenta a la hora del estudio diagnóstico de los pacientes con síncope (AU)

Introduction Syncope is the motivation for numerous diagnostic tests, among them transthoracic echocardiography (TTE); however, previous evidence suggests there is little utility in this test. Our objective was to assess its diagnostic yield in syncope, analysing the effect of age and sex. Material and methods We conducted an observational study that included patients with syncope and who underwent TTE between 1990-2015. We defined diagnostic findings related to syncope and performed a descriptive analysis, assessing the diagnostic yield (overall and according to age and sex). Results The study included 3,302 patients and measured a diagnostic yield of 8.8%; the most common finding was ventricular dysfunction (4.5%). The probability of a diagnostic TTE significantly increased with age (p<.001) but was low for patients younger than 50 years (2.3%). The male sex was significantly related with a diagnostic TTE (p<.001), mostly due to the higher rate of ventricular dysfunction. Conclusions The diagnostic yield of TTE in patients with syncope is moderate, low in patients younger than 50 years and lower in women than in men. These factors should be considered when conducting a diagnostic study of patients with syncope (AU)

The effect of age and sex on the diagnostic yield of the echocardiogram in patients with syncope. / Efecto de la edad y el sexo en el rendimiento diagnóstico del ecocardiograma en pacientes con síncope.

INTRODUCTION: Syncope is the motivation for numerous diagnostic tests, among them transthoracic echocardiography (TTE); however, previous evidence suggests there is little utility in this test. Our objective was to assess its diagnostic yield in syncope, analysing the effect of age and sex. MATERIAL AND METHODS: We conducted an observational study that included patients with syncope and who underwent TTE between 1990-2015. We defined diagnostic findings related to syncope and performed a descriptive analysis, assessing the diagnostic yield (overall and according to age and sex). RESULTS: The study included 3,302 patients and measured a diagnostic yield of 8.8%; the most common finding was ventricular dysfunction (4.5%). The probability of a diagnostic TTE significantly increased with age (p<.001) but was low for patients younger than 50 years (2.3%). The male sex was significantly related with a diagnostic TTE (p<.001), mostly due to the higher rate of ventricular dysfunction. CONCLUSIONS: The diagnostic yield of TTE in patients with syncope is moderate, low in patients younger than 50 years and lower in women than in men. These factors should be considered when conducting a diagnostic study of patients with syncope.

Fabrication and Hydrodynamic Characterization of a Microfluidic Device for Cell Adhesion Tests in Polymeric Surfaces.

A fabrication method is developed to produce a microfluidic device to test cell adhesion to polymeric materials. The process is able to produce channels with walls of any spin coatable polymer. The method is a modification of the existing poly-dimethylsiloxane soft lithography method and, therefore, it is compatible with sealing methods and equipment of most microfluidic laboratories. The molds are produced by xurography, simplifying the fabrication in laboratories without sophisticated equipment for photolithography. The fabrication method is tested by determining the effective differences in bacterial adhesion in five different materials. These materials have different surface hydrophobicities and charges. The major drawback of the method is the location of the region of interest in a lowered surface. It is demonstrated by bacterial adhesion experiments that this drawback has a negligible effect on adhesion. The flow in the device was characterized by computational fluid dynamics and it was shown that shear stress in the region of interest can be calculated by numerical methods and by an analytical equation for rectangular channels. The device is therefore validated for adhesion tests.

The effects of surface properties on Escherichia coli adhesion are modulated by shear stress.

The adhesion of Escherichia coli to glass and polydimethylsiloxane (PDMS) at different flow rates (between 1 and 10 ml s(-1)) was monitored in a parallel plate flow chamber in order to understand the effect of surface properties and hydrodynamic conditions on adhesion. Computational fluid dynamics was used to assess the applicability of this flow chamber in the simulation of the hydrodynamics of relevant biomedical systems. Wall shear stresses between 0.005 and 0.07 Pa were obtained and these are similar to those found in the circulatory, reproductive and urinary systems. Results demonstrate that E. coli adhesion to hydrophobic PDMS and hydrophilic glass surfaces is modulated by shear stress with surface properties having a stronger effect at the lower and highest flow rates tested and with negligible effects at intermediate flow rates. These findings suggest that when expensive materials or coatings are selected to produce biomedical devices, this choice should take into account the physiological hydrodynamic conditions that will occur during the utilization of those devices.

96-well microtiter plates for biofouling simulation in biomedical settings.

Microtiter plates with 96 wells are routinely used in biofilm research mainly because they enable high-throughput assays. These platforms are used in a variety of conditions ranging from static to dynamic operation using different shaking frequencies and orbital diameters. The main goals of this work were to assess the influence of nutrient concentration and flow conditions on biofilm formation by Escherichia coli in microtiter plates and to define the operational conditions to be used in order to simulate relevant biomedical scenarios. Assays were performed in static mode and in incubators with distinct orbital diameters using different concentrations of glucose, peptone and yeast extract. Computational fluid dynamics (CFD) was used to simulate the flow inside the wells for shaking frequencies ranging from 50 to 200 rpm and orbital diameters from 25 to 100 mm. Higher glucose concentrations enhanced adhesion of E. coli in the first 24 h, but variation in peptone and yeast extract concentration had no significant impact on biofilm formation. Numerical simulations indicate that 96-well microtiter plates can be used to simulate a variety of biomedical scenarios if the operating conditions are carefully set.

Macroscale versus microscale methods for physiological analysis of biofilms formed in 96-well microtiter plates.

Microtiter plates with 96 wells have become one of the preferred platforms for biofilm studies mainly because they enable high-throughput assays. In this work, macroscale and microscale methods were used to study the impact of hydrodynamic conditions on the physiology and location of Escherichia coli JM109(DE3) biofilms formed in microtiter plates. Biofilms were formed in shaking and static conditions, and two macroscale parameters were assayed: the total amount of biofilm was measured by the crystal violet assay and the metabolic activity was determined by the resazurin assay. From the macroscale point of view, there were no statistically significant differences between the biofilms formed in static and shaking conditions. However, at a microscale level, the differences between both conditions were revealed using scanning electron microscopy (SEM). It was observed that biofilm morphology and spatial distribution along the wall were different in these conditions. Simulation of the hydrodynamic conditions inside the wells at a microscale was performed by computational fluid dynamics (CFD). These simulations showed that the shear strain rate was unevenly distributed on the walls during shaking conditions and that regions of higher shear strain rate were obtained closer to the air/liquid interface. Additionally, it was shown that wall regions subjected to higher shear strain rates were associated with the formation of biofilms containing cells of smaller size. Conversely, regions with lower shear strain rate were prone to have a more uniform spatial distribution of adhered cells of larger size. The results presented on this work highlight the wealth of information that may be gathered by complementing macroscale approaches with a microscale analysis of the experiments.

Influence of flow rate variation on the development of Escherichia coli biofilms.

This work investigates the effect of flow rate variation on mass transfer and on the development of Escherichia coli biofilms on a flow cell reactor under turbulent flow conditions. Computational fluid dynamics (CFD) was used to assess the applicability of this reactor for the simulation of industrial and biomedical biofilms and the numerical results were validated by streak photography. Two flow rates of 374 and 242 L h(-1) (corresponding to Reynolds numbers of 6,720 and 4,350) were tested and wall shear stresses between 0.183 and 0.511 Pa were predicted in the flow cell reactor. External mass transfer coefficients of 1.38 × 10(-5) and 9.64 × 10(-6) m s(-1) were obtained for the higher and lower flow rates, respectively. Biofilm formation was favored at the lowest flow rate because shear stress effects were more important than mass transfer limitations. This flow cell reactor generates wall shear stresses that are similar to those found in some industrial and biomedical settings, thus it is likely that the results obtained on this work can be used in the development of biofilm control strategies in both scenarios.

Chromatin-mediated transcriptional regulation by the yeast architectural factors NHP6A and NHP6B.

The Saccharomyces cerevisiae NHP6A and NHP6B proteins are chromatin architectural factors, functionally and structurally related to the mammalian high mobility group (HMG)-1 and -2 proteins, a family of non-sequence-specific DNA binding proteins. nhp6a nhp6b mutants have various morphological defects and are defective in the induced expression of several RNA polymerase II-transcribed genes. We found that NHP6A/B proteins are also required for full induction of the yeast CHA1 gene. Importantly, CHA1 basal level expression is increased 10-fold in an nhp6a nhp6b double deletion mutant. Micrococcal nuclease and DNase I analysis of the CHA1 gene in this strain showed an open promoter structure, characteristic of the activated state of this promoter, even under non-inducing conditions. To address the possible function of the NHP6A/B proteins in chromatin-mediated gene regulation, we performed whole-genome transcriptional profiling of a Deltanhp6a Deltanhp6b yeast strain. Our results suggest that NHP6A/B proteins play an important regulatory role, repressing as well as potentiating expression of genes involved in several cellular processes, and that NHP6A/B control is exerted at the level of the individual gene.

RANTES plays an important role in the evolution of allograft transplant-induced fibrous airway obliteration.

Although lung transplantation is a widely applied therapeutic modality for end-stage pulmonary disease, the long-term survival following this procedure is limited by the development of bronchiolitis obliterans (BO). We investigated the role of RANTES, a C-C chemokine, in the evolution of fibrous airway obliteration (FAO) using a rat heterotopic tracheal transplant model. RANTES was highly expressed in infiltrating mononuclear cells in both allogeneic and isogeneic grafts as revealed by immunohistochemistry. Using a miniosmotic pump, neutralizing anti-RANTES antibody was locally and continuously infused to allografts, whereas recombinant rat RANTES was administered to isografts. Anti-RANTES antibody treatment decreased the number of CD4(+) infiltrating cells in allotracheas and preserved luminal patency compared with those of allocontrols. However, RANTES infusion in isografts did not induce FAO, even though CD4(+) cell migration was increased by this treatment. It appears that RANTES is relevant to the recruitment of CD4(+) cells and the development of FAO in the process of allorejection. Local administration of anti-RANTES might be a therapeutic option for BO following lung transplantation.

Transcriptional repression of the yeast CHA1 gene requires the chromatin-remodeling complex RSC.

In eukaryotes, DNA is packaged into chromatin, a compact structure that must be disrupted when genes are transcribed by RNA polymerase II. For transcription to take place, chromatin is remodeled via nucleosome disruption or displacement, a fundamental transcriptional regulatory mechanism in eukaryotic organisms. Here we show that the yeast chromatin-remodeling complex, RSC (remodels the structure of chromatin), isolated on the basis of homology to the SWI/SNF complex, is required for proper transcriptional regulation and nucleosome positioning in the highly inducible CHA1 promoter. In the absence of Sth1p/Nps1p (a homolog of Swi2p/Snf2p) or of Swh3p (a homolog of Swi3p), expression of CHA1 in non-induced cells is increased to a level comparable with that of fully induced cells. Furthermore, in non-induced cells depleted for Sth1p/Nps1p or Swh3p, a nucleosome positioned over the TATA box of the CHA1 promoter is disrupted, an architectural change normally only observed during transcriptional induction. In addition, deletion of the gene-specific activator Cha4p did not affect derepression of CHA1 in cells depleted for Swh3p. Thus, CHA1 constitutes a target for the RSC complex, and we propose that RSC is essential for maintaining a repressive chromatin structure at the CHA1 promoter.

[El Nino in Borbon, Ecuador]. / El Niño a Borbón, Ecuador.

The "global" climatic phenomenon of El Niño is described in its "local" expressions and dramatic health implications through the daily chronicle of what happens in an area of the Pacific Amazonia in Ecuador. The report is also an example of how health promoters living with the communities substantially contribute to the comprehensive surveillance of the life, and not only of the health, of micro-populations, which is the characteristics of community epidemiology.

Nucleosome structure of the yeast CHA1 promoter: analysis of activation-dependent chromatin remodeling of an RNA-polymerase-II-transcribed gene in TBP and RNA pol II mutants defective in vivo in response to acidic activators.

The Saccharomyces cerevisiae CHA1 gene encodes the catabolic L-serine (L-threonine) dehydratase. We have previously shown that the transcriptional activator protein Cha4p mediates serine/threonine induction of CHA1 expression. We used accessibility to micrococcal nuclease and DNase I to determine the in vivo chromatin structure of the CHA1 chromosomal locus, both in the non-induced state and upon induction. Upon activation, a precisely positioned nucleosome (nuc-1) occluding the TATA box and the transcription start site is removed. A strain devoid of Cha4p showed no chromatin alteration under inducing conditions. Five yeast TBP mutants defective in different steps in activated transcription abolished CHA1 expression, but failed to affect induction-dependent chromatin rearrangement of the promoter region. Progressive truncations of the RNA polymerase II C-terminal domain caused a progressive reduction in CHA1 transcription, but no difference in chromatin remodeling. Analysis of swi1, swi3, snf5 and snf6, as well as gcn5, ada2 and ada3 mutants, suggested that neither the SWI/SNF complex nor the ADA/GCN5 complex is involved in efficient activation and/or remodeling of the CHA1 promoter. Interestingly, in a sir4 deletion strain, repression of CHA1 is partly lost and activator-independent remodeling of nuc-1 is observed. We propose a model for CHA1 activation based on promoter remodeling through interactions of Cha4p with chromatin components other than basal factors and associated proteins.

[Catheter ablation of atrial flutter. Electrophysiological characterization of posterior and septal isthmus block]. / Ablação por cateter do flutter atrial. Caracterização eletrofisiológica da interrupção da condução pelos istmos posterior e septal.

PURPOSE: Evaluate the different types of conduction blocks obtained between inferior vena cava-tricuspid annulus (posterior isthmus) and between tricuspid annulus-coronary sinus ostium (septal isthmus) after radiofrequency (RF) catheter ablation of atrial flutter (AFL). METHODS: In 16 procedures, 14 patients (pts), 9 male, with type I AFL underwent RF ablation. Atrial activation around tricuspid annulus was performed with a 10-bipole "Halo" catheter (H1-2; H19-20). In sinus rhythm, isthmus conduction was evaluated during proximal coronary sinus (PCS) and low lateral right atrium (H1-2) pacing, before and after linear ablation. According to the wave front of impulse propagation we assessed absence of block (bidirectional conduction); incomplete block (bidirectional conduction with delay in one front of impulse propagation) and complete block (absence of conduction). The PCS/H1-2 interval was measured before and after ablation. RESULTS: Complete isthmus block was achieved in 7 (44%) and incomplete block in 4 (25%) procedures. Conduction block was not achieved in 5 procedures. At a mean follow-up of 12 months, there were no recurrences in the pts with complete block, whereas AFL recurred in the 6 pts with incomplete or no conduction block (p < 0.001). Pts with complete block had delta PCS/H1-2 interval (74.0 +/- 26.0 ms) greater than incomplete (30.5 +/- 7.5 ms) or absent block (p < 0.05). CONCLUSION: The verification of complete isthmus conduction block with atrial multipolar mapping is an effective strategy to assess electrophysiological success and absence of late recurrence in common atrial flutter ablation.

Datin, a yeast poly(dA:dT)-binding protein, behaves as an activator of the wild-type ILV1 promoter and interacts synergistically with Reb1p.

A cis-acting element required for GCN4-independent basal-level transcription of ILV1 was previously identified in our laboratories as a binding site for the REB1 protein (Reb1p). Further deletion analysis of the ILV1 promoter region identified a second element also required for GCN4-independent basal-level ILV1 expression. This second element is an A.T-rich tract (26 As out of 32 nucleotides) situated 15 bp downstream of the Reb1p-binding site. Deletion of both the Reblp site and the poly(dA:dT) element totally eliminates basal activity of the ILV1 promoter. We show that the two elements act synergistically to control ILV1 expression and that the synergistic effect is distance dependent. We demonstrate that (i) datin (Dat1p), the only known poly (dA:dT)-binding protein in yeast, specifically binds to the ILV1 poly(dA:dT) element in vitro; (ii) Dat1p functions as a trans-activating factor in the ILV1 context; and (iii) the synergistic activation observed in vivo between the Reb1p site and the poly(dA:dT) element depends on the presence of the structural gene for Dat1p, DAT1.

Cancer de colon e reto. Analise critica dos resultados de um hospital de interior. / Cancer of colon and rectum Critical analysis of the results in a back country hospital

Os autores analisam 27 pacientes operados no Hospital dos Plantadores de Cana com o diagnostico de cancer colorretal, no periodo compreendido entre junho de 1975 e dezembro de 1980. O grupo era composto por 16 pacientes do sexo feminino (59,3%) e 11 do sexo masculino (40,7%).O individuo mais jovem tinha 29 anos e o mais idoso 87, com a media de idade de 55,3 anos. Os tumores estavam distribuidos pelos colons da seguinte maneira: 12 ao nivel do reto (44, 5%), sete localizados no sigmoide (25,9%), tres no colon esquerdo (11,1%) e cinco no colon direito (18,5%). Em dois pacientes havia tumores sincronicos de colon direito e sigmoide. Usando os criterios de Dukes, os tumores foram assim classificados: Tipo A-12, tipo B-8, tipo C-9 e tipo D-8. Histologicamente 25 pacientes eram portadores de adenocarcinomas e dois apresentavam tumores epidermoides. Em 23 pacientes foram realizadas cirurgias de resseccao do tubo digestivo incluindo a massa neoplasica. Em tres doentes as cirurgias visaram unicamente evitar a obstrucao do tubo gastrointestinal. Em um paciente foi praticada excisao local. Desses pacientes tres faleceram no pos-operatorio imediato, perfazendo um indice de mortalidade de 11,1%, 11 vieram a falecer posteriormente a alta hospitalar, com o minimo de sobrevida de 40 dias e o maximo de dois anos. Em 1/6/82 treze pacientes (48,1%) estavam vivos, com sobrevida superior a cinco anos