1,720,961 research outputs found
Endocannabinoid signaling and epidermal differentiation
No full textEndocannabinoids represent a class of endogenous lipid mediators, that are involved in various biological processes, both centrally and peripherally. The prototype member of this group of compounds, anandamide, regulates cell growth, differentiation and death; this holds true also in the skin, that is the largest organ of the body constantly exposed to physical, chemical, bacterial and fungal challenges. The epidermis is a keratinized multistratified epithelium that functions as a barrier to protect the organism from dehydration, mechanical trauma, and microbial insults, and epidermal differentiation represents one of the best characterized mechanisms of cell specialization. In this review, we shall summarize current knowledge about the main members of the so-called "endocannabinoid system (ECS)", in order to put in a better perspective the manifold roles that they play in skin pathophysiology. In particular, we shall discuss some aspects of the molecular regulation by endocannabinoids of proliferation and terminal differentiation ("cornification") of mammalian epidermis, showing that ECS is finely regulated by, and can interfere with, the differentiation program. In addition, we shall review evidence demonstrating that disruption of this fine regulation might cause different skin diseases, such as acne, seborrhoea, allergic dermatitis, itch, psoriasis and hair follicle regression (catagen), making of ECS an attractive target for therapeutic intervention
The manifold actions of endocannabinoids on female and male reproductive events
No full textEpidemiological studies have highlighted the ever growing use of illegal drugs among teenagers. The negative effects of marijuana (a Cannabis sativa extract) on reproductive health are poorly known among young people, although chronic exposure to delta-9-tetrahydrocannabinol, the main psychoactive constituent of marijuana, impairs human reproductive potential by disrupting menstrual cycle, suppressing oogenesis and impairing embryo implantation and development, in women, and by increasing ejaculation problems, reducing sperm count and motility, and generating loss of libido and impotence, in men. Endocannabinoids, their metabolic enzymes and target receptors form the so called "endocannabinoid system" and they have been demonstrated to respond to fertility signals. In addition, they interfere with hormones, cytokines and other signalling molecules in both female and male reproductive events. In this review, we shall summarize the current knowledge on the endocannabinoid system, and on the multifaceted roles played by endocannabinoids in reproduction along the evolutionary axis from invertebrates to mammals. Furthermore, we shall discuss the potential use of distinct elements of the endocannabinoid system for the diagnosis and/or treatment of human infertility
The manifold actions of endocannabinoids on female and male reproductive events
Full text linkEpidemiological studies have highlighted the ever growing use of illegal drugs among teenagers. The negative effects of marijuana (a Cannabis sativa extract) on reproductive health are poorly known among young people, although chronic exposure to delta-9-tetrahydrocannabinol, the main psychoactive constituent of marijuana, impairs human reproductive potential by disrupting menstrual cycle, suppressing oogenesis and impairing embryo implantation and development, in women, and by increasing ejaculation problems, reducing sperm count and motility, and generating loss of libido and impotence, in men. Endocannabinoids, their metabolic enzymes and target receptors form the so called "endocannabinoid system" and they have been demonstrated to respond to fertility signals. In addition, they interfere with hormones, cytokines and other signalling molecules in both female and male reproductive events. In this review, we shall summarize the current knowledge on the endocannabinoid system, and on the multifaceted roles played by endocannabinoids in reproduction along the evolutionary axis from invertebrates to mammals. Furthermore, we shall discuss the potential use of distinct elements of the endocannabinoid system for the diagnosis and/or treatment of human infertilit
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
The faah gene is the first direct target of estrogen in the testis: Role of histone demethylase LSD1
No full textEstrogen (E2) regulates spermatogenesis, yet its direct target genes have not been identified in the testis. Here, we cloned the proximal 50 flanking region of the mouse fatty acid amide hydrolase (faah) gene upstream of the luciferase reporter gene, and demonstrated its promoter activity and E 2 inducibility in primary mouse Sertoli cells. Specific mutations in the E2 response elements (ERE) of the faah gene showed that two proximal ERE sequences (ERE2/3) are essential for E 2-induced transcription, and chromatin immunoprecipitation experiments showed that E2 induced estrogen receptor β binding at ERE2/3 sites in the faah promoter in vivo. Moreover, the histone demethylase LSD1 was found to be associated with ERE2/3 sites and to play a role in mediating E2 induction of FAAH expression. E 2 induced epigenetic modifications at the faah proximal promoter compatible with transcriptional activation by remarkably decreasing methylation of both DNA at CpG site and histone H3 at lysine 9. Finally, FAAH silencing abolished E2 protection against apoptosis induced by the FAAH substrate anandamide. Taken together, our results identify FAAH as the first direct target of E2. © Springer Basel AG 2012
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
- …
