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El diagnóstico precoz de la enfermedad de Alzheimer mediante la utilización de biomarcadores podría facilitar la instauración y monitorización de intervenciones terapéuticas tempranas con potencial capacidad para modificar significativamente el curso de la enfermedad.

En las cefaleas parece existir una influencia multifactorial, tanto de mecanismos genéticos como ambientales, siendo interesante el estudio de la posible participación de mecanismos epigenéticos en su desarrollo, cronificación y potencial papel como diana terapéutica.

El desarrollo de biomarcadores en sangre para detectar la enfermedad de Alzheimer (EA) representa uno de los avances recientes más significativos y algunos ya están disponibles para la práctica clínica. Por ello, el Grupo de Estudio de Conducta y Demencias de la Sociedad Española de Neurología ha formado un grupo de trabajo para revisar su estado actual y elaborar recomendaciones de consenso para su implementación clínica.

La epigenética se define como el estudio de los mecanismos que regulan la expresión génica sin modificar la secuencia de ADN, siendo entre ellos el más conocido la metilación del ADN. La esclerosis múltiple (EM) es una enfermedad de etiología no del todo conocida, en la que se plantea que la participación de factores ambientales sobre individuos con una determinada predisposición genética, pueden resultar claves para el desarrollo de la enfermedad. Es en esta intersección entre la predisposición genética y los factores ambientales donde la metilación del ADN puede desempeñar un papel patogénico.

El aumento de homocisteína en sangre constituye un conocido factor de riesgo cardiovascular. Los pacientes epilépticos en tratamiento crónico con fármacos antiepilépticos pueden presentar niveles más elevados de homocisteína y, en consecuencia, un potencial aumento del riesgo cardiovascular.

La epigenética es el estudio de los cambios heredables en el ADN sin afectar a las secuencia de nucleótidos. Entre los mecanismos de regulación epigenética, los más estudiados y conocidos hasta la fecha son la metilación del ADN, la modificación de las histonas y los ARN no codificantes. Mediante estos mecanismos se regula la expresividad génica y la alteración de los mismos puede llevar al desarrollo de patologías.

The transport properties of an amorphous polyamide, poly(trymethylhexamethylene terephtalamide) or Trogamid‐T, were determined by different experimental methods. Sorption methods included two electrobalances, one for subatmospheric pressures and the other one up to 20 bar, and a pressure decay cell. Also, a permeability cell was used to measure permeability coefficients for pure gases and a gas mixture. The solubility, diffusion, and permeability coefficients calculated by different methods were in good agreement. With regard to permeability, measurements showed the difference between ideal and real permselectivity. Moreover, the results confirmed the good barrier properties of Trogamid‐T. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 2034–2042, 2006

The developing liver is vascularized through a complex process of vasculogenesis that leads to the differentiation of the sinusoids. The main structural elements of the sinusoidal wall are endothelial and stellate (Ito) cells. We have studied the differentiation of the hepatic sinusoids in avian embryos through confocal colocalization of differentiation markers, in ovo direct labeling of the liver mesothelium, induced invasion of the developing chick liver by quail proepicardial cells, and in vitro culture of chimeric aggregates. Our results show that liver mesothelial cells give rise to mesenchymal cells which intermingle between the growing hepatoblast cords and become incorporated to the sinusoidal wall, contributing to both endothelial and stellate cell populations. We have also shown that the proepicardium, a mesothelial tissue anatomically continuous with liver mesothelium, is able to form sinusoid-like vessels into the hepatic primordium as well as in cultured aggregates of hepatoblasts. Thus, both intrinsic or extrinsic mesothelium-derived cells have the developmental potential to contribute to the establishment of liver sinusoids. Developmental Dynamics 229:465–474, 2004. © 2004 Wiley-Liss, Inc.

The diffusivity of organic solvents in polyepichlorohydrin was studied with two different experimental setups: inverse gas chromatography (IGC) with packed columns and sorption measurements in gravimetric experiments monitored in a Cahn electrobalance. The aim of this work was to test the possibility of solving an inherent problem in the data reduction of IGC measurements, that is, the necessity of characterizing the morphology of the polymer coated on the support (usually given in the so-called geometric factor of the column). Temperatures between 35 and 65°C were used in the IGC experiments, whereas the sorption measurements were performed between 30 and 40°C. Glass beads were used as supports in IGC for obtaining data concerning the variation of the plate height with the average gas velocity, with which the use of the Van Deemter equation allowed the determination of the diffusion coefficient if the geometric factor was known. In the sorption experiments, the diffusion coefficients at different penetrant activities were directly measured. For their extrapolation within the same concentration range used for IGC (infinite dilution of the penetrant), the theoretical model of Vrentas and Duda was used. By a combination of sorption and IGC experiments, the geometric factor of an IGC column could be adjusted, and this allowed the determination of the diffusion parameters of any other solvent in the same column. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 2216–2223, 2003

Abstract: The main purpose of this study was to evaluate the effects of a package of activities, knows as “Portfolio”, on cognitive functioning, self-regulation, and academic achievement. The study was carried out with a group of 40 students from Compulsory Secondary Education (mean age 13 years old) during 12 hours distributed over two school years. A quasi-experimental pretest-posttest-1 and posttest-2 design was employed. Treatment consisted of the administration of specifically selected tasks, assessed in previous studies, from the psycho-pedagogical Instrumental Enrichment Program, the Philosophy for Children Program, and Project Intelligence. The students were evaluated in the criteria variables at the beginning and at the end of treatment, and once again two years later. The results indicate that the procedure was effective in all the variables studied and that gains observed at posttest-1 were maintained for at least two years after the intervention. Some relevant conclusions and suggestions at the educational and scientific level are commented upon.

The purpose of this work is to study the CO 2 transport properties of isotactic poly(3-hydroxybutyrate) (iPHB) blended with a miscible second component, a copolymer of vinylidene chloride (VDC) and acrylonitrile (AN) units. All the investigated blends are rubbery, allowing a reasonable strategy to tough PHB without impairing its original biodegradability. The miscibility required for this purpose was confirmed by differential scanning calorimetry, measuring both the glass transition and melting temperatures of the blends. The melting point depression induced by the copolymer was used to quantify the interactions between the components of the blend. Carbon dioxide transport properties of blends having less than 50% by weight of the copolymer were measured by gravimetric sorption experiments in a Cahn electro balance. The effect of the VDC- co -AN copolymer was to decrease the diffusivity and permeability of the pure iPHB due to its well-known high barrier character.

The effect of the addition of a liquid crystal polymer (Rodrun^®) on the sorption and transport properties of water through films of a polyetherimide (PEI, Ultem 1000) was investigated. A Cahn electrobalance was employed for measuring the water uptake by the polymer samples. Sorption measurements were made with films of PEI, Rodrun, and heterogeneous PEI/Rodrun blends at different water activities at 30°C. In all cases, diffusion and sorption coefficients decreased when the amount of Rodrun increased. Values of the water-sorption isotherms were adjusted to different models. Permeabilities for the different samples were indirectly obtained using experimental values of the solubility and diffusion coefficients described above. Furthermore, permeabilities of the binary composite material were calculated on the basis of those of the pure components and some theoretical assumptions concerning blend morphology. Results were consistent with a Rodrun structure in the composite intermediate between a fibrillar and a laminar morphology. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 73: 323–332, 1999

Excess specific heats of different binary blends involving different levels of relatively strong specific interactions have been determined from specific heats of the pure components and those of the blends. A heat-flux (Calvet) calorimeter and a step-by-step methodology have been used. Blends of poly(hydroxy ether of bisphenol A) (phenoxy resin) with polyesters and polyethers, where specific interactions are supposed to play a role in miscibility, and blends with stronger hydrogen-bond interactions, such as poly(vinyl phenol)/poly(methyl methacrylate) (PVPh/PMMA), have been included in the study. Only the experimental excess specific heat for the PVPh/PMMA blend is negative, whereas those relative to phenoxy blends are all positive. These results have been analyzed on the basis of an association model specifically designed for polymer blends in which miscibility is mainly caused by hydrogen bonding. The model predicts, in all cases, a continuous decrease of the enthalpy of mixing with temperature, i.e., a negative value of ΔCp. Equation of state effects have been included in the theoretical simulations, giving modified trends of the enthalpy of mixing with temperature in a more reasonable agreement with the experimental results.

The Yersinia Yop virulon is an anti‐host system made up of four elements: (i) a type III secretion system called Ysc; (ii) a system designed to deliver bacterial proteins into eukaryotic target cells (YopB, YopD); (iii) a control element (YopN); and (iv) a set of intracellularly delivered proteins designed to disarm these cells or disrupt their communications (YopE, YopH and possibly others). YopM, another Yop protein, binds thrombin and is thus presumed to act as an extracellular effector. Here, we analyzed YopM from Y.enterocolitica and we wondered whether it could also be delivered inside eukaryotic cells. To answer this question we applied the Yop‐Cya reporter strategy. Hybrids made of 141 or 100 N‐terminal residues of YopM fused to Cya were delivered inside PU5–1.8 macrophages by recombinant Y.enterocolitica strains. YopB and YopD were required as translocators. Leakage of the reporters into the macrophage culture supernatant during the bacterial infection increased strongly when YopN was missing, showing that YopN is involved in the control of delivery of YopM inside eukaryotic cells. YopN itself was not delivered into the macrophages. In conclusion, YopM is translocated inside the eukaryotic cells and its physiopathological role should be revised or completed.

The thermal decomposition of miscible blends composed by the poly(hydroxy ether of bis-phenol A) (phenoxy) and poly(ethylene oxide) (PEO) has been investigated by dynamic thermogravimetric analysis. The results obtained indicate that the blend composition affects the thermal decomposition processes. In general it can be seen that phenoxy causes a negative effect on the thermal stability of the blends.

We compared the effect of verapamil slow-release (VSR) and the combination of nifedipine plus propranolol on transient myocardial ischemia in a double-blind study comprising 20 patients with proven coronary artery disease and chronic stable angina. According to the results of 24-h Holter-monitoring recording, patients were divided into two groups: 10 patients with fixed coronary reserve and 10 patients with variable coronary reserve. The number of ischemic events was reduced with both therapies: from 12 ± 10 at baseline to 3.4 ± 4.0 (p < 0.05) with verapamil and to 3.9 ± 7.0 (p < 0.05) with nifedipine plus propranolol (N P). When total ischemic burden was measured, findings were similar: It was reduced from 104 ± 196 min to 27 ± 57 (p < 0.05) with N P and to 17 ± 18 min with verapamil in patients with fixed coronary reserve and from 36 ± 44 to 5 ± 9 min (p < 0.05) with verapamil and to 5 ± 10 min with N P in patients with a variable coronary reserve. VSR shows antiischemic efficacy similar to that of the combination of N P in treatment of transient myocardial ischemia in patients with stable angina.

The chromosome of Yersinia enterocolitica encodes a heat-stable enterotoxin called Yst and a surface antigen called Myf, which closely resembles enterotoxin-associated fimbriae. Both factors could act in conjunction to produce diarrhea. Production of the enterotoxin is regulated by temperature, osmolarity, and pH and occurs only when bacteria reach the stationary phase. Myf production is regulated by temperature and pH and, as we show in this work, also occurs after the exponential growth phase. In an attempt to understand the late-phase expression of yst and myf, we cloned, sequenced, and mutagenized the gene encoding RpoS, an alternative sigma factor of the RNA polymerase involved in expression of stationary-phase genes in other enterobacteria. An intact rpoS gene was necessary for full expression of yst in the stationary phase but not for the expression of myf and of pYV-encoded virulence determinants.

Extracellular Yersinia disables the immune system of its host by injecting effector Yop proteins into host cells. We show that a Yersinia enterocolitica nonpolar lcrG mutant is severely impaired in the translocation of YopE, YopH, YopM, YpkA/YopO, and YopP into eukaryotic cells. LcrG is thus required for efficient internalization of all the known Yop effectors.

A researcher from Araba University Hospital in Vitoria Gasteiz, Spain, has conducted a study on the compliance and evaluation of direct observation as a surveillance method for preventing healthcare-associated infections (HAIs) and the acquisition of multidrug-resistant bacteria (MDR-B) in intensive care units. The study found good compliance with recommendations, but also identified areas where compliance was lacking. The researcher emphasized the importance of developing evidence-based projects to address the problem of HAIs and MDR-B, and highlighted the need for effective surveillance methods to monitor and improve these projects. The study was published in the European Journal of Public Health. [Extracted from the article]

Photosensitizing properties of hypericin are well known, and the chicken chorioallantoic membrane has previously been used to test photodynamic effects of hypericin and other substances. In our study the photodynamic effect of hypericin in the ex ovo quail chorioallantoic membrane model was evaluated. Steady-state and time-resolved fluorescence spectroscopy of hypericin solution in PEG-400 and its mixture in PBSwas performed to assess and characterize the process of aggregation and disaggregation of hypericin during the drug formulation preparation. A therapeutical formulation (2 μg/g of embryo weight) was topically applied on CAM into the silicone ring. Hypericin was excited by diode laser with wavelength 405 nm, fluence rate 140 mW/cm², and fluence 16.8 J/cm². Hypericin in 100% PEG-400 exhibits typical fluorescence spectra with a maximum of about 600 nm, while hypericin 10% PEG-400 formulation exhibits almost no fluorescence. Time resolved spectra analysis showed fluorescence decay of hypericin in 100% PEG-400 solution with a mean lifetime of 5.1 ns and in 10% PEG 4.1 ns. Damage of quail chorioallantoic membrane vasculature after photodynamic therapy ranged from hemorrhage and vanishing of capillary vessels to thrombosis, lysis, and hemorrhage of larger vessels. The presented findings suggest that quail embryos can be used as a suitable model to test the effect of hypericin and other photodynamic compounds. [ABSTRACT FROM AUTHOR]

Study objective: To examine the relation between left atrial (LA) function and exercise performance. Design and setting: Retrospective study at a referral cardiopulmonary exercise laboratory in a university hospital. Patients: Forty-one patients with recent myocardial infarction. Interventions: M-mode echocardiography and cardiopulmonary exercise testing combined with radionuclide ventriculography. Measurements and results: Hemodynamic measurements were obtained at rest and peak exercise. LA fractional shortening at rest was used as an index of global LA function. LA fractional shortening had fair correlations with peak oxygen consumption (r=0.67, p [is less than] 0.01) and exercise duration (r=0.71, p [is less than] 0.01). Although there were no significant relations between LA fractional shortening and hemodynamic measurements at rest, LA fractional shortening was positively related to peak cardiac output (r=0.61, p [is less than] 0.01) and peak stroke volume (r=0.57, p [is greater than] 0.01), and negatively related to peak pulmonary arterial wedge pressure (r= -0.44, p [is less than] 0.05). In addition, LA fractional shortening correlated significantly with an increase in left ventricular (LV) enddiastolic volume from rest to peak exercise (r=0.48, p [is less than] 0.02), but did not correlate with the changes in ejection fraction and end-systolic volume during exercise. An increase in LV end-diastolic volume during exercise was significantly related to peak oxygen consumption (r=0.46, p [is less than] 0.02), peak cardiac output (r=0.60, p [is less than] 0.01), and peak stroke volume (r=0.53, p [is less than] 0.01), whereas the changes in ejection fraction and end-systolic volume during exercise were not related to these indexes. Conclusions: Exercise capacity and LV performance during exercise were mainly dependent on LV diastolic filling rather than systolic contraction during exercise. LA fractional shortening at rest reflected LV diastolic filling during exercise and, therefore, predicted cardiac output and stroke volume responses to exercise and exercise capacity in patients with recent myocardial infarction. (CHEST 1997, 111:922-28) Key words: exercise capacity; left atrial function; myocardial infarction Abbreviations: LA= left atrial; LV=left ventricular, In patients with left ventricular (LV) dysfunction, impaired exercise tolerance is one of the most common clinical manifestations. Previous studies have demonstrated poor correlations between indexes of LV systolic function [...]

About 20% of patients with chest pain and treadmill evidence of myocardial ischemia have coronary arteries that look normal at angiography. What does this mean? Is more testing necessary? Is [...]

Study objectives: To investigate the importance of early left ventricular (LV) diastolic filling on maintenance of exercise performance, we examined peak filling rate and its relation to exercise capacity during upright bicycle exercise in patients with recent myocardial infarction. Design: Retrospective analysis of data of cardiopulmonary exercise testing characteristics in patients with recent myocardial infarction. Setting: Coronary care unit in a university hospital. Patients: Fifty-one patients 3 to 6 weeks after acute myocardial infarction. Interventions: Upright bicycle exercise using a symptom-limited graded exercise protocol. Measurements and results: Peak filling rate increased significantly from 1.55 ± 0.52 at rest to 3.43 ± 1.1 end-diastolic volume per second at peak exercise. Despite no significant relation between peak filling rate at rest and peak oxygen consumption, peak filling rate at peak exercise correlated significantly with peak oxygen consumption (r=0.50; p [is less than] 0.002), stroke volume (r=0.51; p [is less than] 0.002), and cardiac output (r=0.56; p [is less than] 0.002) at peak exercise. Although both end-systolic and end-diastolic volumes increased from rest to peak exercise, the increases in end-systolic volume correlated inversely with the changes in peak filling rate during exercise (r=-0.45; p [is less than] 0.02), but the increases in end-diastolic volume did not. Conclusions: During maximal upright bicycle exercise, exercise capacity and exercise hemodynamic responses were mainly dependent on early LV diastolic filling, and preserved LV systolic contraction, resulting in a cardiac suction effect following early diastole, seemed to have an important role in the enhancement of early LV diastolic filling in patients with recent myocardial infarction. (CHEST 1997;111:590-94) Key words: exercise capacity; myocardial infarction; peak filling rate Abbreviations: LV=left ventricular, Measurements of left ventricular (LV) function that predict exercise capacity in patients with LV dysfunction remain elusive. Previous studies have shown that measurements of LV systolic function are poor predictors [...]