1,720,958 research outputs found
Experimental data about Antioxidants inhibition during equine sperm capacitation
No full textIn vitro embryo production (IVP) is a highly demanded technique in the animal breeding industry. However, the conventional protocol based on in vitro fertilization (IVF) still shows low success rates in horses. For this reason, intracytoplasmic sperm injection (ICSI) is currently the most widely used method. Unlike in other species where IVF has long been established and yields higher success rates than ICSI, equine sperm capacitation remains a significant challenge. A repeatable IVF protocol was only published in 2022, which requires prolonged sperm capacitation (22 hours at 38 ºC), and not all ejaculates can withstand this process. Given the growing interest in applying IVF to equine reproduction and the known involvement of reactive oxygen species (ROS) in sperm capacitation, this study aimed to enhance sperm capacitation in fresh semen by inhibiting intracellular antioxidant systems, using three specific inhibitors. The study compared the previously described capacitation protocol (CAP) with a non-capacitating control (CTR) and with CAP supplemented with the inhibitors, through four independent experiments:
- Experiment 1: Capacitation in the presence of 3-amino-1,2,4-triazole (3-AT), a catalase inhibitor.
- Experiment 2: Capacitation with LCS-1, an inhibitor of superoxide dismutase 1 (SOD1).
- Experiment 3: Capacitation with L-Buthionine-(S,R)-Sulfoximine (BSO), an inhibitor of
γ-glutamylcysteine synthetase, a key enzyme in glutathione (GSH) synthesis.
- Experiment 4: Assessment of capacitation progression with a combination of the three inhibitors used in the previous experiments.
In experiments 1-3, sperm samples were incubated for 22 hours at 38 ºC and evaluated at 0, 3, and 22 hours. In experiment 4, samples were incubated for 24 hours and analyzed every 3 hours.
The datasets include flow cytometry data on sperm viability, mitochondrial membrane potential, membrane lipid scrambling, intracellular calcium and ROS levels, and protein tyrosine phosphorylation. Additionally, they include kinetic sperm parameters analyzed by computer-assisted sperm analysis (CASA)
Experimental data about Effects of Nanoplastics exposure in mature equine spermatozoa
No full textThe current global plastic pollution of all ecosystems allows the accumulation of micro- and nanoplastics (MNPs) in human and animal tissues. These particles have been associated with negative effects on fertility, primarily through inflammation and oxidative stress in reproductive organs. Given the limited research on how MNPs affect gametes, this study aimed to evaluate MNPs internalization and related effects in mature spermatozoa, using frozen-thawed stallion sperm exposed to various concentrations of 30 nm polystyrene nanoplastics (NP).
The datasets include flow cytometry data on sperm viability, intracellular reactive oxygen species levels, mitochondrial membrane potential, mean fluorescence intensity (MFI) of H2DCFDA, and mean fluorescence intensity (MFI) of fluorescent nanoplastics (FNP). Additionally, they include kinetic sperm parameters analyzed by computer-assisted sperm analysis (CASA). Semen samples were incubated for 3 hours at 38 ºC with or without 30 nm NP at 10, 50, 100 or 200 µg/mL
Extracellular cAMP and MRP4 activity influence in vitro capacitation and fertilizing ability of pig spermatozoa
Full text linkcAMP has been reported to be an essential driver of sperm capacitation. In bovine sperm cAMP efflux through multidrug resistance-associated protein 4 (MRP4) has been suggested to maintain intracellular cAMP homeostasis and generate extracellular signaling able to regulate capacitation. The aim of this work was to determine whether extracellular cAMP may influence in vitro pig sperm capacitation and acquisition of fertilizing ability and to evaluate the role of MRP4. In vitro sperm capacitation and gamete coincubation were performed in Brackett and Oliphant's medium (BO) in presence of caffeine (Ctr+) or in BO without caffeine (Ctr-) supplemented with 0, 8, 9, 10 mM cAMP. Despite the percentage of capacitated sperm, assayed by immunolocalization of tyrosine-phosphorylated proteins, was significantly lower in Ctr- compared to Ctr+, it increased supplementing 10 mM cAMP to Ctr- reaching values similar to Ctr+. The absence of caffeine during gamete coincubation reduced the fertilization rate compared to Ctr+, while 10 mM cAMP supplementation to Ctr- increased the fertilization rate reaching values similar to Ctr + .
The presence of MRP4 in pig spermatozoa was detected for the first time by western blot and immunohistochemistry assays. To evaluate MRP4 role on pig sperm capacitation, in vitro capacitation and gamete coincubation were performed in Ctr + in presence of MK571, a MRP4 selective inhibitor. MK571 reduced the percentage of capacitated cells and the fertilization rate, while cAMP addition fully reversed MRP4 blockade consequences.
Present findings suggest that, under our in vitro conditions, extracellular cAMP and MRP4 activity influence pig sperm capacitating events
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
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
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
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