1,720,983 research outputs found
Structural and Functional Significance of the Endoplasmic Reticulum Unfolded Protein Response Transducers and Chaperones at the Mitochondria–ER Contacts: A Cancer Perspective
No full textIn the last decades, the endoplasmic reticulum (ER) has emerged as a key coordinator of cellular homeostasis, thanks to its physical interconnection to almost all intracellular organelles. In particular, an intense and mutual crosstalk between the ER and mitochondria occurs at the mitochondria–ER contacts (MERCs). MERCs ensure a fine-tuned regulation of fundamental cellular processes, involving cell fate decision, mitochondria dynamics, metabolism, and proteostasis, which plays a pivotal role in the tumorigenesis and therapeutic response of cancer cells. Intriguingly, recent studies have shown that different components of the unfolded protein response (UPR) machinery, including PERK, IRE1α, and ER chaperones, localize at MERCs. These proteins appear to exhibit multifaceted roles that expand beyond protein folding and UPR transduction and are often related to the control of calcium fluxes to the mitochondria, thus acquiring relevance to cell survival and death. In this review, we highlight the novel functions played by PERK, IRE1α, and ER chaperones at MERCs focusing on their impact on tumor development
Green tea polyphenols affect invasiveness of human gastric MKN-28 cells by inhibition of LPS or TNF-α induced Matrix Metalloproteinase-9/2
No full textSeveral studies demonstrated a correlation between green tea consumption and a reduced cancer risk. Among different components, green tea polyphenols have been identified as molecules responsible for the beneficial effects showed by the green tea against oxidative stress and cell invasiveness. In this study, we investigated the effects of green tea polyphenol extracts (GTPs) in human gastric MKN-28 cell line. To this aim, we have first evaluated the effect of GTPs on oxidative stress induced cell injury. The pre-treatment with 10−4 M catechin equivalents of GTPs exerts a protective effect on xanthine–xanthine oxidase induced cell cytotoxicity, thus confirming the anti-oxidant properties of GTPs. The effect of GTPs was also extended to the invasive ability of MKN-28 cells stimulated with TNF-α or LPS, as pro-inflammatory factors. Migration and matrigel invasion assays demonstrated that GTPs exposure (10−6 M) prevents the increase in cell invasiveness induced by TNF-α or LPS. Finally, we have analyzed the effect of GTPs on the levels of Matrix Metalloproteinases (MMP)-9/2, whose expression is up-regulated by TNF-α or LPS. Our results indicated that the pre-treatment with GTPs was able to reduce MMP-9/2 expression at both protein and enzyme activity levels in the conditioned media of TNF-α or LPS stimulated MKN-28 cells. In conclusion, our results demonstrated that green tea polyphenol extract reduces the invasiveness of gastric MKN-28 cancer cells through the reduction of TNF-α or LPS induced MMP-9/2 up-regulation. Therefore, these data support the hypothesis that GTPs could exert a protective role against the metastatic process in gastric cancer
Myostatin and plasticity of skeletal muscle tissue
Full text linkSkeletal muscle is an extremely plastic tissue for its ability to respond to different stimuli such as physiological variation and external stress. Muscle hypertrophy involves an increase in muscle mass, changes in myofibril composition and adaptation of metabolic pathways. Plasticity of skeletal muscle in response to exercise training is also caused by proliferation and differentiation of the satellite muscle stem cells in response to various growth and differentiation factors. This process is mainly mediated by myokines secreted during skeletal muscle contraction. Myokines are proteins that act as hormones both locally in the muscle and/or in an endocrine manner in other organs, mainly liver, brain and adipose tissue. Myostatin, known as growth differentiation factor-8, a myokine member of transforming growth factor-b (TGF-b) superfamily, can act on muscle cells in an autocrine manner leading to inhibition of muscle myogenesis. Muscle myostatin expression and its plasma concentration are downregulated after acute and long-term physical exercise thus allowing muscle hypertrophy. In addition, myostatin is correlated to obesity and insulin resistance for its ability to affect energy metabolism and insulin-sensitivity in muscle cells, respectively. These findings reveal that myostatin may have potential therapeutic applications to treat muscle atrophy diseases in humans. Even in sports, drugs able to inhibit myostatin expression can lead athletes to increase their sport performance. Here, we present a brief overview of myostatin and its role in biological mechanisms involved in exercise-induced plasticity of skeletal muscle
Circadian rhythms, physical activity and longevity
Full text linkHuman health implies complex mechanisms and involves diseases prevention aimed at ensuring a psycho-physical wellbeing homoeostasis. The search for longevity can be related to the slowdown in aging, and psycho-physical wellbeing is often related to the lifestyle, mainly to the human physical activity and nutrition. Circadian rhythms are processes that affect the behaviour, physiology and metabolism of mammals across cyclic periods of 24 hours. These rhythms are regulated by multiple physiological systems, whose key elements are the alternation between light and dark and between food consumption and periods of fasting. Therefore, during evolution, a constant adaptation to natural rhythms by humans has been established towards the surrounding environment determining periods of food consumption and periods of fasting coinciding with rest. Recent sociological surveys have shown that there is a slight increase in the number of people who devote themselves to a constant physical/sport activity, but this is an ephemeral percentage compared to the dramatic increase in the incidence of diseases related to aging such as obesity and diabetes, easily preventable with healthy lifestyles. Therefore, the connection between circadian rhythms, physical activity and lifestyles represents an important feature involved in human longevity. Here, a survive of the biological mechanisms, implied in this behaviour, is presented
Green Tea Polyphenols Affect Invasiveness of Human Gastric MKN-28 Cells by Inhibition of LPS or TNF-alpha Induced Matrix Metalloproteinases-9/2
No full textGreen tea polyphenols have been identified as molecules responsible for the beneficial effects showed by the green tea against oxidative stress and cancer risk. We investigated the effects of green tea polyphenol extracts (GTPs) on oxidative stress and cell invasiveness in human gastric MKN-28 cancer cells. The pre-treatment with 10–4 M catechin equivalents of GTPs exerts a protective effect on xanthine-xanthine oxidase induced cell cytotoxicity, thus confirming the anti-oxidant properties of GTPs. The effect of GTPs was also extended on the cell migration and invasive ability induced by TNF-alpha or LPS. Results demonstrated that GTPs exposure (10–6 M) prevents the increase in cell invasiveness induced by the inflammatory agents. In addition, the treatment with GTPs prevented the TNF-alpha or LPS induced Matrix Metalloproteinases (MMP)-9/2 up-regulation. Our results demonstrated that GTPs reduced the oxidative stress and the invasive potential of gastric MKN-28 cancer cells thus confirming the protective role of these polyphenols against the metastatic process in gastric cancer
Analysis of Psychological and Biological Parameters in Patients Affected by Anorexia Nervosa or Obesity
No full textBackground: Depression and anxiety disorders have a high comorbidity with eating disorders (EDs), especially
anorexia nervosa (AN) and obesity. This concomitance may complicate the diagnosis and treatment of these
disorders. Aim 1: to study psychological and biological factors having significant roles in anxiety and depression
in ED patients. Aim 2: to evaluate differences in ED individuals having anorexia nervosa and obesity. Methods:
ED patients (n° 20 with anorexia nervosa; n° 15 with obesity) were enrolled at the Eating Disorder Unit of ASL
Napoli 2 (Campania, Italy) and ASL Salerno (Campania, Italy) between January 2019 and January 2020. From
all subjects we collected sociodemographic data, body mass index (BMI) and blood samples routinely tested for
insulin, aspartate aminotransferase (AST) and alanine aminotransferase (ALT). We administered the State Trait
Anxiety Inventory Scale (STAI) and Beck Depression Inventory-II (BDI-II) to assess the severity and chronicity
of EDs and the presence of anxious and depressive symptoms. Results: We observed significant differences in
the mean values of BMI in the groups of patients with AN (BMI = 16,28) or (BMI = 30,90) have clinical values
that meet the diagnostic criteria while having normative values for Control group CRT (BMI = 22,1).
Conclusions: The presence of several disorders at the same time can increase the severity and chronicity of EDs
and make a favourable outcome of the treatment more problematic. Furthermore, the correlation between
biological and psychological factors in our understanding of comorbidity in EDs patients may have implications
for the evaluation and treatment of this population
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
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