Intra-His bundle block: clinical, electrocardiographic, and electrophysiologic characteristics

OBJECTIVE: To assess the clinical, electrocardiographic, and electrophysiologic characteristics of patients (pt) with intra-His bundle block undergoing an electrophysiologic study (EPS). METHODS: We analyzed the characteristics of 16 pt with second-degree atrioventricular block and symptoms of syncope or dyspnea, or both, undergoing conventional EPS. RESULTS: Intra-His bundle block was documented in 16 pt during an EPS. In 15 (94%) pt, the atrioventricular block was recorded in sinus rhythm; 4 (25%) pt had intra-His Wenckebach phenomenon, which correlated with Mobitz I (MI) atrioventricular block on the electrocardiogram. Seven (44%) pt had 2:1 atrioventricular block, 2 of whom were asymptomatic (12.5%). One (6%) pt had intra- and infra-His bundle block. Clinically, 11 (68%) pt had syncope or presyncope, 3 (18%) had dyspnea on exertion, and 2 (12.5%) were asymptomatic. Eight (50%) pt had bundle-branch block as follows: 4 (25%) pt had left bundle-branch block, and 4 (25%) had right bundle-branch block. Left anterosuperior divisional block was observed in 3 pt (19%), 2 of whom with associated right bundle-branch block. CONCLUSION: Intra-His bundle block was observed in 11% of the pt with second-degree atrioventricular block, syncope or presyncope, or both, it being the most frequent clinical presentation. Intra-His bundle block was more common in the elderly (> 60 years) and among females. The most frequent electrocardiographic presentations were second-degree Mobitz I or type 2:1 atrioventricular block.

Diseño y caracterización de plataformas de biorreconocimiento basadas en el uso de nanoestructuras, biomoléculas y polímeros. Aplicaciones para el desarrollo de (bio)sensores electroquímicos. Design and characterization of biorecognition platforms based on the use of nanostructures, biomolecules and polymers. Applications for the development of electrochemical (bio)sensors.

Los requerimientos de métodos analíticos que permitan realizar determinaciones más eficientes en diversas ramas de la Química, así como el gran desarrollo logrado por la Nanobiotecnología, impulsaron la investigación de nuevas alternativas de análisis. Hoy, el campo de los Biosensores concita gran atención en el primer mundo, sin embargo, en nuestro país es todavía un área de vacancia, como lo es también la de la Nanotecnología. El objetivo de este proyecto es diseñar y caracterizar nuevos electrodos especialmente basados en el uso de nanoestructuras y estudiar aspectos básicos de la inmovilización de enzimas, ADN, aptámeros, polisacáridos y otros polímeros sobre dichos electrodos a fin de crear nuevas plataformas de biorreconocimiento para la construcción de (bio)sensores electroquímicos dirigidos a la cuantificación de analitos de interés clínico, farmaco-toxicológico y ambiental.Se estudiarán las propiedades de electrodos de C vítreo, Au, "screen printed" y compósitos de C modificados con nanotubos de C (CNT) y/o nanopartículas (NP) de oro y/o nanoalambres empleando diversas estrategias. Se investigarán nuevas alternativas de inmovilización de las biomoléculas antes mencionadas sobre dichos electrodos, se caracterizarán las plataformas resultantes y se evaluarán sus posibles aplicaciones analíticas al desarrollo de biosensores con enzimas y ADNs como elementos de biorreconocimiento. Se funcionalizarán CNT con polímeros comerciales y sintetizados en nuestro laboratorio modificados con moléculas bioactivas. Se diseñarán y caracterizarán nuevas arquitecturas supramoleculares basadas en el autoensamblado de policationes, enzimas y ADNs sobre Au. Se evaluarán las propiedades catalíticas de NP de magnetita y de perovskitas de Mn y su aplicación al desarrollo de biosensores enzimáticos. Se diseñarán biosensores que permitan la detección altamente sensible y selectiva de secuencias específicas de ADNs de interés clínico. Se estudiará la interacción de genotóxicos con ADN (en solución e inmovilizado) y se desarrollarán biosensores que permitan su cuantificación. Se construirán biosensores enzimáticos para la cuantificación de bioanalitos, especialmente glucosa, fenoles y catecoles, y sensores electroquímicos para la determinación de neurotransmisores, ácido úrico y ácido ascórbico. Se diseñarán nuevos aptasensores electroquímicos para la cuantificación de biomarcadores, comenzando por lisozima y trombina y continuando con otros de interés regional/nacional.Se emplearán las siguientes técnicas: voltamperometrías cíclica (CV), de pulso diferencial (DPV) y de onda cuadrada (SWV); "stripping" potenciométrico a corriente constante (PSA); elipsometría; microbalanza de cristal de cuarzo con cálculo de pérdida de energía por disipación (QCM-D); resonancia de plasmón superficial con detección dual (E-SPR); espectroscopía de impedancia electroquímica (EIE); microscopías de barrido electroquímico (SECM), de barrido electrónico (SEM), de transmisión (TEM) y de fuerzas atómicas (AFM); espectrofotometría UV-visible; espectroscopías IR, Raman, de masas, RMN.Se espera que la inclusión de los CNT y/o de las NP metálicas y/o de los nanoalambres en los diferentes electrodos permita una mejor transferencia de carga de diversos analitos y por ende una detección más sensible y selectiva de bioanalitos empleando enzimas, ADN y aptámeros como elementos de biorreconocimiento. Se espera una mayor eficiencia en los aptasensores respecto de los inmunosensores, lo que permitirá la determinacion selectiva de diversos biomarcadores. La modificación de electrodos con nanoestructuras posibilitará la detección altamente sensible y selectiva del evento de hibridación. La respuesta obtenida luego de la interacción de genotóxicos con ADN permitirá un mejor conocimiento de la asociación establecida, de la cinética y de las constantes termodinámicas. Los neurotransmisores podrán ser determinados a niveles nanomolares aún en muestras complejas.

Polímeros a partir de fuentes renovables. Polymers from renewable resources.

Las poliolefinas (polietileno y polipropileno) y el poliestireno se obtienen por polimerización de monómeros derivados del petróleo. La utilización creciente del petróleo incrementa la emisión a la atmósfera de gases que provocan el recalentamiento global. Por otra parte, la escasez de reservas de petróleo provocó en los últimos años un incremento en el precio del crudo y en el de sus derivados. Por tal motivo, esto pone de manifiesto el interés actual por reemplazar al petróleo y al gas natural por materias primas renovables. El ácido poliláctico (APL) y el poli(3-hidroxibutirato) (PHB) son poliésteres de origen bacteriano que poseen propiedades termoplásticas y elastómeras similares a los plásticos derivados del petróleo, pero son biodegradables y se producen a partir de sustratos renovables. Sin embargo, su costo es aún demasiado elevado. Una de las estrategias utilizadas para abaratarlos es la utilización de sustratos de costo bajo o nulo (residuos agroindustriales y permeado de lactosuero). Por lo tanto, el principal objetivo de este proyecto es sintetizar plásticos biodegradables alternativos a los polímeros sintéticos ya existentes a partir de recursos renovables de bajo costo. En particular, se pretende utilizar permeado de lactosuero proveniente de distintas industrias de San Francisco y su zona. San Francisco se encuentra estratégicamente ubicada dentro de una de las principales cuencas lecheras de este país. Los trabajos a desarrollar serán teórico y experimentales, y se relacionan con la síntesis y caracterización de los productos y el modelado de dichos procesos. Desde el punto de vista experimental se pretende: a) sintetizar el bio-monómero (ácico láctico) y los polímeros (APL y PHB) ; b) caracterizar el bio-monómero y los polímeros mediante el empleo de técnicas volumétricas, espectroscópicas y cromatográficas; y c) medir propiedades finales (fundamentalmente mecánicas) y establecer las relaciones estructuras-propiedades. Desde el punto de vista teórico se modelarán los procesos de síntesis (bio-monómero) y polimerización. Los modelos se utilizarán para la predicción de características físicas y moleculares de los productos finales, para la simulación y la optimización de procesos, y para complementar técnicas de caracterización. Este proyecto se enmarca dentro de la Química Verde o Sustentable con lo cual se pretende incentivar el desarrollo de productos más saludables y químicamente adaptados al medio ambiente que reemplacen a los polímeros sintéticos existentes sin la pérdida de sus propiedades finales. De este modo, se espera que los resultados contribuyan al conocimiento científico y tecnológico y resulten de interés regional e internacional.

Functional Capacity of Patients with Pacemaker Due to Isolated Congenital Atrioventricular Block

Background:Isolated congenital atrioventricular block (CAVB) is a rare condition with multiple clinical outcomes. Ventricular remodeling can occur in approximately 10% of the patients after pacemaker (PM) implantation.Objectives:To assess the functional capacity of children and young adults with isolated CAVB and chronic pacing of the right ventricle (RV) and evaluate its correlation with predictors of ventricular remodeling.Methods:This cross-sectional study used a cohort of patients with isolated CAVB and RV pacing for over a year. The subjects underwent clinical and echocardiographic evaluation. Functional capacity was assessed using the six-minute walk test. Chi-square test, Fisher's exact test, and Pearson correlation coefficient were used, considering a significance level of 5%.Results:A total of 61 individuals were evaluated between March 2010 and December 2013, of which 67.2% were women, aged between 7 and 41 years, who were using PMs for 13.5 ± 6.3 years. The percentage of ventricular pacing was 97.9 ± 4.1%, and the duration of the paced QRS complex was 153.7 ± 19.1 ms. Majority of the subjects (95.1%) were asymptomatic and did not use any medication. The mean distance walked was 546.9 ± 76.2 meters and was strongly correlated with the predicted distance (r = 0.907, p = 0.001) but not with risk factors for ventricular remodeling. (Arq Bras Cardiol. 2014; [online].ahead print, PP.0-0)Conclusions:The functional capacity of isolated CAVB patients with chronic RV pacing was satisfactory but did not correlate with risk factors for ventricular remodeling.

Dipyridamole stress myocardial perfusion by computed tomography in patients with left bundle branch block

Abstract Background: Functional tests have limited accuracy for identifying myocardial ischemia in patients with left bundle branch block (LBBB). Objective: To assess the diagnostic accuracy of dipyridamole-stress myocardial computed tomography perfusion (CTP) by 320-detector CT in patients with LBBB using invasive quantitative coronary angiography (QCA) (stenosis ≥ 70%) as reference; to investigate the advantage of adding CTP to coronary computed tomography angiography (CTA) and compare the results with those of single photon emission computed tomography (SPECT) myocardial perfusion scintigraphy. Methods: Thirty patients with LBBB who had undergone SPECT for the investigation of coronary artery disease were referred for stress tomography. Independent examiners performed per-patient and per-coronary territory assessments. All patients gave written informed consent to participate in the study that was approved by the institution’s ethics committee. Results: The patients’ mean age was 62 ± 10 years. The mean dose of radiation for the tomography protocol was 9.3 ± 4.6 mSv. With regard to CTP, the per-patient values for sensitivity, specificity, positive and negative predictive values, and accuracy were 86%, 81%, 80%, 87%, and 83%, respectively (p = 0.001). The per-territory values were 63%, 86%, 65%, 84%, and 79%, respectively (p < 0.001). In both analyses, the addition of CTP to CTA achieved higher diagnostic accuracy for detecting myocardial ischemia than SPECT (p < 0.001). Conclusion: The use of the stress tomography protocol is feasible and has good diagnostic accuracy for assessing myocardial ischemia in patients with LBBB.

Optimal design in the presence of random or fixed block effects

Magdeburg, Univ., Fak. für Mathematik, Diss., 2014

Juridical double taxation by cross border transactions: the Block Case (C-67/08)

Treaty Establishing the European Community, operative until December 1st 2009, had already established in its article 2 the mission of the up until then European Community and actual European Union is to promote an harmonious, equilibrated and sustainable development of the economic activities of the whole Community. This Mission must be achieved by establishing a Common Market, an Economic and Monetary Union and the realization of Common Policies. One of the instruments to obtain these objectives is the use of free circulation of people, services and capitals inside the Common and Interior Market of the European Union. The European Union is characterized by the confirmation of the total movement of capitals, services and individuals and legal peoples’ freedom; freedom that was already predicated by the Maastricht Treaty, through the suppression of whatever obstacles which are in the way of the objectives before exposed. The old TEC in its Title III, now Title IV of the Treaty on the Functioning of the European Union, covered the free circulation of people, services and capitals. Consequently, the inclusion of this mechanism inside one of the regulating texts of the European Union indicates the importance this freedom supposes for the European Union objectives’ development. Once stood up the relevance of the free movement of people, services and capitals, we must mention that in this paper we are going to centre our study in one of these freedoms of movement: the free movement of capital. In order to analyze in detail the free movement of capital within the European framework, we are going to depart from the analysis of the existent case law of the Court of Justice of the European Union. The use of jurisprudence is basic to know how Community legislation is interpreted. For this reason, we are going to develop this work through judgements dictated by the European Union Court. This way we can observe how Member States’ regulating laws and the European Common Law affect the free movement of capital. The starting point of this paper will be the Judgement C-67/08 European Court of Justice of February 12th 2009, known as Block case. So, following the argumentation the Luxemburg Court did about the mentioned case, we are going to develop how free movement of capital could be affected by the current disparity of Member States’ legislation. This disparity can produce double taxation cases due to the lack of tax harmonized legislation within the interior market and the lack of treaties to avoid double taxation within the European Union. Developing this idea we are going to see how double taxation, at least indirectly, can infringe free movement of capital.

The antibody response in mice to carrier-free synthetic polymers of Plasmodium falciparum circumsporozoite repetitive epitope is I-Ab-restricted: possible implications for malaria vaccines.

The immunogenicity of a novel synthetic peptide consisting of an average of 40 (Asn-Ala-Asn-Pro) repeats of the circumsporozoite protein of Plasmodium falciparum, (NANP)40, was studied in mice without using any carrier proteins. First, high titers of anti-(NANP)40 antibodies could be obtained after immunization of C57BL/6 mice. These antibodies also reacted with an extract of mosquitoes infected with P. falciparum sporozoites. C57BL/6 nu/nu mice did not produce antibodies against (NANP)40. Secondly, when 14 strains of mice with nine different H-2 haplotypes were immunized with (NANP)40 without carrier, only H-2b mice were found to produce anti-(NANP)40 antibodies, whereas all non-H-2b mice were consistently unresponsive. This response was demonstrated to be I-A-linked by using recombinant and mutant mice. I-Ab [B10.A(5R)] mice produced anti-(NANP)40 antibodies as well as H-2b inbred mice. B6CH-2bm12 I-Ab-mutant mice showed only a very low response. Third, the antibody response against (NANP)40 could be induced in nonresponder mice by immunization with the peptide coupled to a carrier protein. In view of the existence of such an exceptional H-2b restriction in the response to sporozoite synthetic peptides in mice, the triggering of peptide-specific T cell responses in humans receiving sporozoite malaria vaccines might be difficult to achieve.

Human urothelial cells grown on collagen adsorbed to surface-modified polymers.

OBJECTIVES: Tissue engineering methods can be applied to regenerate diseased, or congenitally missing, urinary tract tissues. Urinary tract tissue cell cultures must be established in vitro and adequate matrices, acting as cell carriers, must be developed. Although degradable and nondegradable polymer matrices offer adequate mechanical stability, they are not optimal for cell adherence and growth. To overcome this problem, extracellular matrix proteins, permitting cell adhesion and regulation of cell proliferation and differentiation, can be adsorbed to the surface-modified polymer. METHODS: In this study, nondegradable polymer films, poly(ethylene terephthalate), were used as an experimental model. Films were modified by graft polymerization of acrylic acid to subsequently allow collagen type I and III immobilization. The following adhesion, proliferation of human urothelial cells, and induction of their stratification were analyzed. RESULTS: Collagen adsorption on 0.2 microg/cm2 poly(acrylic acid)-grafted polymer films rendered the matrix apt for human urothelial cell adhesion and proliferation. Furthermore, stratification of urothelial cells was demonstrated on these surface-modified matrices. CONCLUSIONS: These results have shown that surface-modified polymer matrices can be used to act as cell carriers for cultured human urothelial cells. Such a cell-matrix construct could be applied in reparative surgery of the urinary tract.

Effect of Knotting on the Shape of Polymers

Momentary configurations of long polymers at thermal equilibrium usually deviate from spherical symmetry and can be better described, on average, by a prolate ellipsoid. The asphericity and nature of asphericity (or prolateness) that describe these momentary ellipsoidal shapes of a polymer are determined by specific expressions involving the three principal moments of inertia calculated for configurations of the polymer. Earlier theoretical studies and numerical simulations have established that as the length of the polymer increases, the average shape for the statistical ensemble of random configurations asymptotically approaches a characteristic universal shape that depends on the solvent quality. It has been established, however, that these universal shapes differ for linear, circular, and branched chains. We investigate here the effect of knotting on the shape of cyclic polymers modeled as random isosegmental polygons. We observe that random polygons forming different knot types reach asymptotic shapes that are distinct from the ensemble average shape. For the same chain length, more complex knots are, on average, more spherical than less complex knots.