1,721,008 research outputs found
Intrauterine growth restriction : implications for placental metabolism and transport . A review
No full textIntrauterine growth restriction (IUGR) correlates with a specific placental phenotype, associated with defects in placental transport functions, that lead to fetal undernutrition. Both placental metabolism and transport may be affected, thus modifying the normal supply of nutrients. Models to investigate placental
function may either couple or separate metabolism and transport. In human pregnancies, nutrient concentrations can be measured at the time of delivery or at cordocentesis in the umbilical vessels
connecting the fetus to the placenta. The kinetics of placental transport can be evaluated in vivo using stable isotopes, i.e. infusing 13C labelled nutrient in the mother by bolus or steady state techniques prior to cordocentesis or cesarean section. In vitro studies, using the model of the dually perfused human placenta or investigating the activity of transporters in the placental membranes have also significantly contributed to our understanding of placental function.
In IUGR, the placental supply of amino acids is significantly reduced independently from the severity of growth restriction and from the presence of hypoxia. Moreover, maternal–fetal gradients of glucose are increased in severe IUGR fetuses, i.e. those with alterations of umbilical blood flows, and reduced conversion ratios of long chain-polyunsaturated fatty acids (LC-PUFA) from their parent fatty acids have been demonstrated. This review summarizes the current knowledge about placental metabolism and transport in IUGR pregnancies and the relationship with severity of the disease
Ruolo degli acidi grassi omega-3 LC-PUFA in gravidanza e allattamento
No full textGli acidi grassi polinsaturi a lunga catena (LC-PUFA) della famiglia omega-3, principalmente l’acido eicosapentaenoico
(EPA) e l’acido docosaesanoico (DHA), sono implicati in numerose reazioni biologiche,
tra cui la modulazione del processo infiammatorio, interferendo nella produzione eicosanoidi. Per questo motivo sono stati proposti per la cura di patologie correlate a un meccanismo infiammatorio cronico (artrite reumatoide, colon irritabile, asma), per la prevenzione del rischio aterogeno cardiovascolare, più recentemente
di quello aritmogeno e anche per la prevenzione di sindromi psichiatriche (depressione). Per alcuni di questi scopi sono necessari ulteriori studi che chiariscano il beneficio portato da queste sostanze, per altri, come l’utilizzo in ambito cardiologico, rappresentano una realtà ben consolidata. Per quanto riguarda
l’ambito ostetrico e pediatrico il DHA, contenuto nel pesce, si è dimostrato capace di influenzare la durata della gravidanza e la crescita fetale e neonatale con notevoli ripercussioni sullo sviluppo neurologico e visivo del bambino. Molti studi hanno riportato una relazione positiva tra un più alto consumo di pesce da parte delle donne e un ridotto rischio di parto pre-termine, di basso peso alla nascita, un miglioramento cognitivo, della coordinazione e del comportamento neonatale. La fonte di LC-PUFA per il feto è rappresentata dalla madre che con una corretta dieta può fornire un quantitativo idoneo di DHA e altri LC-PUFA. Ciò prosegue durante l’allattamento durante il quale la quantità di DHA contenuta nel latte materno è direttamente proporzionale alla quantità assunta con la dieta
Progetto Conca Velina - Rieti
No full textIl progetto di ricognizione archeologica "Conca Velina" è finalizzato alla realizzazione della carta archeologica del comprensorio della conca reatina e dell'area del Lago di Piediluco e cascata delle Marmore. Il progetto è realizzato in regime di convenzione con la Soprintendenza per i Beni Archeologici del Lazio. Nel 2011 sono stati indagati settori del Comune di Riet
Le parole fantasma nei dizionari storici: nuove proposte per alcuni casi dai commenti danteschi
No full textLe parole fantasma, noto argomento al confine tra filologia e lessicografia, non sono altro che fraintendimenti testuali derivati da errori di trascrizione, del copista o dell’editore. L’intervento intende indagare questa categoria nel TLIO, nel cui Corpus non mancano alcune edizioni di riferimento poco affidabili che costituiscono la principale causa della redazione di voci in realtà non esistenti nell’italiano antico, tuttavia spesso consapevolmente commentate dai redattori con apposite note. In particolare si propone l’illustrazione di alcuni casi tratti dall’Ottimo commento, per cui il TLIO fa riferimento all’edizione Torri (Pisa, Capurri, 1827-1829)
Lipid profile in intrauterine growth restriction
No full textReduction in the intrauterine supply of nutrients might lead to Intrauterine growth restriction alterations of the fetal growth trajectory that results in attainment of fetal own growth potential missed. IUGR is, together with premature delivery, the most relevant cause of perinatal mortality and morbidity, affecting approximately 7–15% of pregnancies. Although maternal, placental, and fetal causes may reduce the potential for fetal growth, no known causes can be detected in most cases of IUGR. These cases share a common placental phenotype, also called for many years “placental insufficiency.” In the last years many studies have described the vascular, metabolic, and endocrine changes occurring in IUGR, although the initiating factors are still to be understood. IUGR fetuses show a decreased deposition of tissue as a result of reduced uptake of nutrients from the umbilical circulation. In particular, the fetal fat component seems to be affected. Among nutrients, some fatty acids are particularly relevant for fetal nutrition and pregnancy outcome. In particular, the long chain polyunsaturated fatty acids (LCPUFA) of the n-3 and n-6 series, i.e., arachidonic acid (AA) and docosahexaenoic acid (DHA) need to be made available through the placenta since they cannot be synthesized in the fetus. They are important structural elements of cells guaranteeing the plasticity of the membranes; they are needed for the normal development of the central nervous system and retina. The biological roles of omega-3 and omega 6 FA involve eicosanoid metabolism, membrane properties, and regulation of gene expression. Significant changes in the ratios between the LCPUFA DHA and AA and their precursors ALA and LA have been reported in IUGR sampled at cordocentesis when compared to normally grown fetuses of similar gestational age. Altered availability of LCPUFA in preterm IUGR might have an important role in the increased brain damage susceptibility shown by these fetuses
La nascita del progetto pilota nazionale Vespasiano e la scuola: la Summer school e i portali web del MIBAC e del MIUR
No full textGoing Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Only severe intrauterine growth restriction (IUGR) alters expression levels of low density lipoprotein receptor-related protein (LRP) and scavenger receptor class B type I (SR-BI)
No full textFetal nutrition : a review
Full text linkKnowledge of fetal nutrient supply has greatly increased in the last decade due to the availability of fetal blood samples
obtained under relatively steady-state conditions. These studies, together with studies utilizing stable isotope methodologies,
have clarified some aspects of the supply of the major nutrients for the fetus such as glucose, amino acids and fatty acids. At the
same time, the relevance of intrauterine growth has been recognized not only for the well-being of the neonate and child, but
also for later health in adulthood. The major determinants of fetal nutrient availability are maternal nutrition and metabolism
together with placental function and metabolism. The regulation of the rate of intrauterine growth is the result of complex
interactions between genetic inheritance, endocrine environment and availability of nutrients to the fetus
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