Effect of polyunsaturated fatty acid deficiency on dipole relaxation in the membrane interface of rat liver microsomes

AbstractThe influence of a fat-free diet on the lipid dynamics of rat liver microsomes and liposomes of microsomal lipids was studied by using different fluorescence methods. Lifetime distribution and rotational diffusion of probes with different localization in the lipid bilayer were measured using multifrequency fluorometry. Lateral mobility was studied by measuring excimer formation of pyrenedodecanoic acid. Dipolar relaxation in the interfacial region was studied using 2-dimethylamino-6-lauroylnaphthalene (Laurdan). In spite of large changes in the fatty acid composition of microsomal lipids, polyunsaturated fatty acid deficiency showed no effect on the lifetime distribution and rotational mobility of 1,6-diphenyl-1,3,5-hexatriene (DPH), 1-(4-(trimethylamino)phenyl)-6-phenyl-1,3,5-hexatriene (TMA-DPH), 2-, 7- and 12-(9-anthroiloxy)stearic acids. The treatment did not change the lateral diffusion of pyrenedodecanoic acid, either. However, generalized polarization of Laurdan fluorescence was higher in polyunsaturated fatty acid deficient microsomes as compared to the polyunsaturated fatty acid sufficient ones. This effect was also observed in liposomes of the total microsomal lipids, indicating that the changes in fatty acid composition resulting from polyunsaturated fatty acid deficiency produced a small but significant decrease in the rate of dipolar relaxation in the region of the lipid polar groups of the bilayer. The absence of lipid gel phase domains in rat liver microsomes was also indicated by Laurdan fluorescence features

An archaeobotanical and stable isotope approach to changing agricultural practices in the NW Mediterranean region around 4000 BC

It has recently been observed, that a change in the crop spectrum happened during the so-called Middle Neolithic in France at ca. 4000 BC. An agricultural system based on free-threshing cereals (naked wheat and naked barley) seems to shift to one based on glume wheats. This is a major change for traditional farmers and this paper aims to shed light on its possible causes. Here we describe the results of new investigations in a key area for the understanding of this process: the NW Mediterranean arch, where free-threshing cereals are the main cultivars since ca. 5100 BC. New data confirm that the shift towards glume wheats is also observed in some sites of the NE of the Iberian Peninsula and that among the glume wheats that spread at ca. 4000 BC we should not only consider emmer and einkorn but also Timopheevi’s wheat. Stable isotope analyses indicate no major decrease in soil fertility or alterations in local precipitation regimes. The agricultural change may be the result of a combination of the spread of damaging pests for free-threshing cereals and presumably new networks being developed with the North-eastern part of Italy and the Balkans

Efecto de los ácidos grasos W3 sobre la estructura de membranas y actividad del NHE-1 en ratas normotensas y espontáneamente hipertensas (SHR)

Los ácidos grasos de la serie w-3 han sido asociados experimental y epidemiológicamente a diversos estados fisiopatológicos, como inflamación, diabetes, enfermedad cardiovascular y cáncer. Uno de los mecanismos moleculares mediante los cuales estos ácidos grasos ejercen su efecto biológico consiste en su incorporación en membranas celulares, afectando las propiedades biofísicas y bioquímicas de las mismas, impactando específicamente sobre la estructura y organización de lipid rafts, la localización de proteínas de vías de señalización y, en definitiva, sobre numerosas funciones celulares. Los lipid rafts se definen como dominios especializados de membranas biológicas, enriquecidos en esfingolípidos (SLs) y colesterol (Col), que reclutan proteínas específicas. Las caveolas son un tipo especializado de rafts que se caracteriza por su estructura invaginada de 50-100 nm de diámetro, revestida y estabilizada por caveolinas y cavinas, entre otras proteínas. El intercambiador Na+/H+ (NHE-1), una proteína integral de membrana, está involucrado en el mantenimiento del pH intracelular (pH ). Su actividad está regulada por la sensibilidad del sitio alostérico i para el H+, fosforilación y por la unión de ATP, lípidos y factores de crecimiento. Diversos estudios en corazón de ratas SHR han demostrado la hiperactividad de dicho transportador, y que la inhibición del mismo revierte la hipertrofia que éstos presentan. El objetivo es estudiar la composición lipídica y contenidos de PUFAs de la serie w3 en sangre de ratas normotensas (Wistar) y espontáneamente hipertensas (SHR), en relación con la organización de membrana plasmática –lipid rafts/caveolas- y actividad del intercambiador Na+ /H+ miocárdico (NHE-1)

La dirección de centros educativos en Iberoamérica : reflexiones y experiencias

La presente aportación recoge la visión de más de veinticinco especialistas de doce países iberoamericanos sobre aspectos de la dirección de centros educativos. Su presentación exige unas reflexiones tanto sobre la temática como sobre el contenido. En relación con la temática, la dirección, entendida como sistema de dinamización, apoyo y acompañamiento a la actuación pedagógica e institucional, lejos de estar en crisis, se considera cada vez más necesaria. Los centros de formación y los profesores se enfrentan a situaciones nuevas, diversas y complejas, consecuencia de una realidad más dinámica, de una sociedad más exigente y de unos usuarios más conscientes de la calidad de servicios que precisan. La nueva situación hace pertinente que las respuestas educativas tengan en cuenta la complejidad de los fenómenos y sean diferenciadas en función del contexto y de los destinatarios, resaltando la necesidad y conveniencia de toma de decisiones fundamentadas y de apoyos vinculados a su desarrollo. El desarrollo de la temática de dirección que se aborda en el presente texto recoge aportaciones de diversa naturaleza. Por una parte, aquellas que han venido trabajando cuatro equipos con profesionales de diferentes países durante seis meses; por otra, recoge otras tres complementarias realizadas también por equipos de especialistas. Su realización se vincula al encuentro de especialistas de la Red de Apoyo a la Gestión Educativa (Red AGE: http://www.redage.org) realizado en el mes de junio de 2010 en la ciudad de Santiago de Chile. Allí, los representantes de las organizaciones miembro presentaron y debatieron sobre la situación actual de la dirección escolar en sus respectivos países, que constituyen la base sobre la que se han realizado las aportaciones definitivas que recoge el presente texto. Se cubre así un propósito fundamental de la Red AGE, como es el de fomentar el intercambio de experiencias, la profesionalización de los directivos y la promoción del conocimiento sobre administración y gestión educativa. La finalidad última es la de mejorar el funcionamiento de las instituciones formativas (y, a través de ellas, de los sistemas formativos), procurando sean de calidad y un instrumento para el cambio profesional y social

Direct Phenotypical and Functional Dysregulation of Primary Human B Cells by Human Immunodeficiency Virus (HIV) Type 1 In Vitro

BACKGROUND: Human immunodeficiency virus type 1 (HIV-1) induces a general dysregulation of immune system. Dysregulation of B cell compartment is generally thought to be induced by HIV-related immune activation and lymphopenia. However, a direct influence of HIV-1 particles on B cells was recently proposed as the third pathway of B cells dysregulation. METHODS/PRINCIPAL FINDINGS: We evaluated the direct and specific consequences of HIV-1 contact on activation, survival, proliferation and phenotype of primary B cells in vitro. Moreover, we examined expression of activation-induced cytidine deaminase (AID) mRNA that is responsible for class switch recombination (CSR) and somatic hypermutation (SHM). Here, we report that changes observed in cellular proliferation, phenotypes and activation of B cells could be caused by direct contact between HIV-1 particles and primary B cells in vitro. Finally, direct HIV-1-derived B cells activation led to the increase of AID mRNA expression and its subsequent CSR function was detected in vitro. CONCLUSION/SIGNIFICANCE: We showed that HIV-1 could directly induce primary B cells dysregulation triggering phenotypical and functional abilities of B cells in vitro that could explain in some extent early B-cell abnormalities in HIV disease

Mortality and pulmonary complications in patients undergoing surgery with perioperative SARS-CoV-2 infection: an international cohort study

Background: The impact of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) on postoperative recovery needs to be understood to inform clinical decision making during and after the COVID-19 pandemic. This study reports 30-day mortality and pulmonary complication rates in patients with perioperative SARS-CoV-2 infection. Methods: This international, multicentre, cohort study at 235 hospitals in 24 countries included all patients undergoing surgery who had SARS-CoV-2 infection confirmed within 7 days before or 30 days after surgery. The primary outcome measure was 30-day postoperative mortality and was assessed in all enrolled patients. The main secondary outcome measure was pulmonary complications, defined as pneumonia, acute respiratory distress syndrome, or unexpected postoperative ventilation. Findings: This analysis includes 1128 patients who had surgery between Jan 1 and March 31, 2020, of whom 835 (74·0%) had emergency surgery and 280 (24·8%) had elective surgery. SARS-CoV-2 infection was confirmed preoperatively in 294 (26·1%) patients. 30-day mortality was 23·8% (268 of 1128). Pulmonary complications occurred in 577 (51·2%) of 1128 patients; 30-day mortality in these patients was 38·0% (219 of 577), accounting for 81·7% (219 of 268) of all deaths. In adjusted analyses, 30-day mortality was associated with male sex (odds ratio 1·75 [95% CI 1·28–2·40], p\textless0·0001), age 70 years or older versus younger than 70 years (2·30 [1·65–3·22], p\textless0·0001), American Society of Anesthesiologists grades 3–5 versus grades 1–2 (2·35 [1·57–3·53], p\textless0·0001), malignant versus benign or obstetric diagnosis (1·55 [1·01–2·39], p=0·046), emergency versus elective surgery (1·67 [1·06–2·63], p=0·026), and major versus minor surgery (1·52 [1·01–2·31], p=0·047). Interpretation: Postoperative pulmonary complications occur in half of patients with perioperative SARS-CoV-2 infection and are associated with high mortality. Thresholds for surgery during the COVID-19 pandemic should be higher than during normal practice, particularly in men aged 70 years and older. Consideration should be given for postponing non-urgent procedures and promoting non-operative treatment to delay or avoid the need for surgery. Funding: National Institute for Health Research (NIHR), Association of Coloproctology of Great Britain and Ireland, Bowel and Cancer Research, Bowel Disease Research Foundation, Association of Upper Gastrointestinal Surgeons, British Association of Surgical Oncology, British Gynaecological Cancer Society, European Society of Coloproctology, NIHR Academy, Sarcoma UK, Vascular Society for Great Britain and Ireland, and Yorkshire Cancer Research