1,721,026 research outputs found
Impatto della produzione epatica e pancreatica di PCSK9 sull'omeostasi glucidica
No full textLa proproteina convertasi subtilisina/kexina tipo 9 (PCSK9), controllando l'espressione del
recettore per LDL, gioca un ruolo fondamentale nella regolazione dei livelli ematici di
colesterolo. Varianti geniche di PCSK9 caratterizzate da perdita di funzione si associano a
concentrazione ematiche di LDL-colesterolo più basso, ma aumentata glicemia a riposo e
rischio di diabete di tipo 2, suggerendo un ruolo di PCSK9 nel controllo dell’omeostasi
glucidica. Inoltre, per quanto il fegato sia il principale produttore di PCSK9 circolante, anche il
pancreas endocrino produce PCSK9, indicando un possibile ruolo diretto della proteina in
questo tessuto. Scopo del lavoro è stato pertanto comprendere il contributo della produzione
epatica e pancreatica di PCSK9 sul controllo dell’omeostasi glucidica.
Topi condizionali, privi dell’espressione di PCSK9 selettivamente nel fegato (topo
AlbuminaCre/Pcsk9LoxP/LoxP) o nel pancreas (topo Pdx1Cre/Pcsk9LoxP/LoxP) mantenuti a dieta
standard per 20 settimane (Standard fat diet, 10% ac grassi), sono stati analizzati per la
tolleranza al glucosio (GTT), l’insulina ematica e la morfologia dell’isola.
I topi privi di PCSK9 epatica, come atteso, non presentano livelli circolanti di PCSK9
significativi, ma continuano ad esprimere PCSK9 nelle isole pancreatiche e mostrano curve
GTT e livelli di glucosio ematico simili ai topi controllo. Le isole di questi animali presentano
dimensioni, organizzazione e contenuto di insulina comparabili a quelli controllo, suggerendo
che PCSK9 epatico giochi un ruolo minore nel controllo dell’omeostasi glucidica.
Topi privi di PCSK9 a livello pancreatico, presentano normali livelli circolanti di PCSK9 ma
mancano dell'espressione di PCSK9 nell’isola e sono glucosio intolleranti. La glucosiointolleranza sembra essere dovuta ad un difetto di insulino deficienza perchè la secrezione di
insulina indotta da un carico glucidico è significativamente più bassa in questi animali rispetto
ai controlli. L'analisi della morfologia del pancreas rivela isole del Langerhans di dimensioni e
contenuto insulinico paragonabili ai controlli. Sono in corso studi per comprendere il ruolo del
PCSK9 pancreatico nella secrezione di insulina.
Questi dati indicano che PCSK9 pancreatico e non circolante (prodotto dal fegato) svolge un
ruolo importante nell’omeostasi glucidica, suggerendo pertanto che terapie anti-PCSK9
rivolte verso la proteina circolante e proposte per soggetti con elevata colesterolemia non
alterino la funzionalità pancreatica
Impact of pancreatic PCSK9 on intracellular organelles architecture and dynamics in beta-cells: implication in insulin processing and secretion
No full textImpact of a phenol-enriched extract from olive vegetation water on the oxidative stability of low-nitrite würstels
No full textThe reduction of nitrites in cooked meat products is becoming a topic of primary importance, both for manufacturers and for consumers. However, their complete or partial replacement with a single natural compound is a challenge, due to the multifunctional characteristics of nitrites. One possible approach is the use of natural antioxidants from Mediterranean vegetal sources, such as olives and their processing by-products, which are rich in phenolic compounds. In particular, olive mill wastewaters (OMWW) generated during virgin olive oil production contain the majority of hydrophilic phenols (mainly secoiridoids and its derivates, which are found exclusively in the Oleaceae family), which are known to have high antioxidant and antimicrobial activities. Thus, if phenols are extracted from OMWW and purified by suitable membrane technology, they can be used for the formulation of healthier cooked meat products, with a reduced content of nitrate salts.
The aim of this study was to evaluate the effect of an extract rich in phenols (PE), obtained from OMWW, on the oxidative stability and sensory characteristics of steam-cooked and grilled würstels during storage. The steam cooked würstels were prepared with beef (50%), lean pork (20%) and lard (30%), ice (20%), salt (1.25%), ascorbic acid (0.02%), aromas (0.33%) and liquid smoke (0.05%). The ingredients were homogenized until complete emulsion and, the dough was then divided into four batches: Control (NO2 150 mg/kg) and 3 PE-enriched samples (W1, W2 and W3, with PE 200 mg/kg + NO2 35/150/0 mg/kg). The emulsion was bagged into a collagen bowel and cooked in a steam oven until 72°C. After cooling in the blast chiller, würstels were peeled, vacuum-packed, pasteurized at 75°C for 20 min and stored under alternating exposure to fluorescent light at 4±2°C for 30 days. Steam cooked würstels were sampled at fixed time periods (0, 15 and 30 days of storage) and frozen at -80°C. At the same sampling times, the same number of steam cooked würstels from each batch were grilled at 200°C for 3.30 min per side until 70°C was reached at core. After processing and grilling, about 60% of total phenols were retained in PE samples. Regarding primary lipid oxidation, peroxide value (PV) in the control sample tripled in 30 days, while in W1 and W3 samples the final PV were 74% and 71% lower, respectively. Furthermore, no significant effect of storage on the PV of PE samples was observed. The steam-cooked control sample showed an increase in both conjugated dienes and trienes during storage, while these parameters remained almost constant in ungrilled PE samples. After grilling, all samples showed the classical bell-shape behavior of primary oxidation products. Regarding secondary lipid oxidation, VOCS largely confirmed the role of PE in limiting the increase of C5 and C6 saturated aldehydes that derive from lipid oxidation, being up to 36% lower in PE samples than in the control after 30-day storage, and up to 25% lower after grilling. In addition, grilled samples had TBARs values that were about 2 times higher than those of steam-cooked würstels, confirming the pro-oxidant effect of grilling. However, TBARs in both steam-cooked and grilled control würstels were lower than those of the PE samples during storage. Regarding COPs and COR%, no significative differences were found between PE and control steam-cooked würstel samples. No taste anomalies were detected for all products, confirming their stability during chilled displaying. Samples were only discriminated by a grayer color, which is due to the addition of a lower quantity of NO2 in the formulation of PE samples.
This study confirms that it is possible to produce healthier low-nitrate würstels with improved oxidative stability by using PE from OMWW, thus representing a good strategy to valorize by-products of the olive oil food chain and to promote industrial symbiosis
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
- …
