1,720,982 research outputs found
Effects of Ca2+ ions on the interactions between antithrombin III and factor Xa mediated by variously-sulfated semi-synthetic low-molecular-weight heparins
No full textA homogeneous set of low-molecular weight heparins, chemically modified to yield different degrees of sulfation (SD), were investigated in their ability of interfering with the Antithrombin III (AT III)-Factor Xa (FXa) interaction process in the presence/absence of physiological concentrations of calcium ions. The heparin-AT III dissociation constants were not appreciably affected by the presence of the metal ion, whereas the catalytic process was strongly dependent upon Ca2+. Our data suggest that AT III binding to heparin represents the main factor driving the FXa inhibition process. In addition, the presence of the metal ion is likely to mask favorable AT III- heparin ionic contacts occurring with the highly sulfated material. These results help in assessing proper structure-activity relationships for glycosaminoglycans, a multi-target family of biologically active compounds
Clinical effects of vatinoxan co-administered with medetomidine and methadone in healthy dogs undergoing isoflurane anaesthesia
No full textVatinoxan mitigates the cardiovascular effects of medetomidine but may cause hypotension during general anaesthesia and may alter plasma concentrations of co-administered analgesics (Kallio-Kujala et al., 2022). This study examines cardiovascular variables and methadone plasma levels in anesthetized dogs premedicated intramuscularly with vatinoxan, medetomidine, and methadone.
This study enrolled 16 healthy dogs, weighing 2.5 to 46 kg, undergoing elective midline ovariectomy. The animals received medetomidine (0.15 mg m-2) and methadone (0.2 mg kg-1) premedication with vatinoxan (3 mg m-2; group MVM) or without vatinoxan (group MM). Anaesthesia was induced with propofol 20 minutes after the injection and maintained with isoflurane in oxygen. Clinical variables, including HR, non-invasive MAP, and end-tidal concentration of isoflurane (EtISO), were recorded at maximal traction of both ovarian pedicles and at skin suture. Methadone plasma concentration (cM) was measured at 15 (T15) and 90 (T90) minutes after premedication. Propofol dose and cM were compared between groups with a Student’s t-test, and a linear mixed model was used to analyse the effect of time and group on clinical variables.
Propofol dose did not differ between groups. Time and group did not show any statistically significant effects on haemodynamic and respiratory variables. During anaesthesia, mean HR was 76 ± 21 and 91 ± 22 beats minute-1 and mean MAP was 88 ± 14 and 94 ± 16 mmHg in group MM and MVM, respectively. In both groups EtISO ranged between 0.6 and 1.8 %. A statistically significant difference between groups was found in cM only at T90 with a lower value in group MVM than MM (13.2 ± 3.0 vs 17.2 ± 3.4 ng ml-1; p = 0.024).
The co-administration of vatinoxan in dogs premedicated with methadone and medetomidine may affect the plasma concentration of the opioid, although cardiovascular variables do not appear to present clinically relevant variations
Interactions of low-molecular-weight semi-synthetic sulfated heparins with human leukocyte elastase and human Cathepsin G
No full textSemi-synthetic low-molecular-weight heparin samples (LMWHs), having homogeneous
degree of polymerization and saccharide backbone, but differing in the number and location
of sulfate groups, were investigated in their ability to interfere with the pharmacologically
relevant targets human leukocyte elastase (EL) and human Cathepsin G (CatG). Spectroscopic
studies were performed for a quantitative evaluation of the enzyme-inhibitor dissociation
constant, Ki, and of the IC50 values for the inhibition of cleavage of target peptide
sequences. Both proteases are inhibited by the tested polysaccharides through a mixed
hyperbolic binding process. A non-linear relationship was found between degree of sulfation
and binding affinity or enzyme inhibition properties, showing a composite correlation
between heparin charge density and interference with EL/CatG activity
Going 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
Variations on the Author
Full text link“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
Full text linkWe 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
Pyrrolizidine alkaloid concentrations in local Italian and retail honeys of different origin: A scenario of human exposure
No full textA validated method in liquid chromatography tandem mass spectrometry was applied to assess the contamination profile of 17 pyrrolizidine alkaloids and their N-oxide metabolites (PAs/PANOs) in 775 honey samples of different origins, including from local beekeepers (579, LB), large retail and online stores (Italian (LRI) and foreign (LRF) products). Fifty-five percent of the honey samples contained the 17 monitored compounds at below the limit of quantification. The LB samples were characterised by a total mean concentration of PAs/PANOs at 6.7 and 3.3 times lower than those of the LRF and LRI samples, respectively. The PA echimidine characterised mainly honey samples from the large retail stores (75.8 % and 72.5 % of LRI- and LRF-contaminated samples, respectively). The LB samples showed a senecionine-type contamination profile, providing beekeepers clues to the plants responsible for contamination. The results highlighted that the consumption of the local honey samples analysed does not represent a double risk for human health compared to the consumption of products from large retail stores. Careful attention must be paid to honey imported from areas where lycopsamine-type and senecionine-type PAs/PANOs-producing plants are invasive. A machine learning approach could predict the origin of the sample given its contaminant profile at an accuracy of 0.74, which is useful for detecting fraud in the declared honey origin
Metal ion-mediated assembly of effective phenanthroline-based G-quadruplex ligands
No full textRecently, a number of metal ion complexes were evaluated for
G-quadruplexbinding.Here, we showed that assembly of otherwise
inactive planar structures through metal coordination may represent
an effective strategy to achieve selective G-quadruplex
binding and recognition. Metal ions, on the other hand, can play
an important role in modulating affinity and stoichiometry of
complex formation. Therefore, it is possible to play with the nature
of the ion species as well as of the ligands to produce a variety of
complexes rationally designed for specifically targeting/damaging
DNA. This represents a promising approach to work out novel
biochemical probes and diagnostic tools in addition to new
chemical entities for drug design and development
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe 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
- …
