1,721,005 research outputs found
Immunotoxicological impact of occupational and environmental nanoparticles exposure: The influence of physical, chemical, and combined characteristics of the particles
Full text linkWhile nanotechnology is growing exponentially, the knowledge of the impact of nanoparticles (NPs) on public health
and the environment is limited so far. Current nanomaterial research is focused on the applications of nanotechnology,
whereas there is little information on exposure assessment and risk characterization associated with NPs. Therefore,
it is essential that the factors influencing NPs associated hazards be studied. This review seeks to survey and evaluate
the current literature in order to better understand the impact of both airborne and engineered NPs exposure, the
mechanisms at the cellular level, and the factors influencing their immunotoxicity. In fact, NPs do have immunotoxicological
significance, as immune cells in the bloodstream and tissues do act to eliminate or interact with NPs.
Proper characterization of the NPs as well as understanding the processes occurring on the NPs surface when in
contact with biological systems is crucial to predict or exclude toxicological effects
Biological clocks: their relevance to immune-allergic diseases
Full text linkAbstract The 2017 Nobel Prize for Physiology or Medicine, awarded for the discoveries made in the past 15 years on the genetic and molecular mechanisms regulating many physiological functions, has renewed the attention to the importance of circadian rhythms. These originate from a central pacemaker in the suprachiasmatic nucleus in the brain, photoentrained via direct connection with melanopsin containing, intrinsically light-sensitive retinal ganglion cells, and it projects to periphery, thus creating an inner circadian rhythm. This regulates several activities, including sleep, feeding times, energy metabolism, endocrine and immune functions. Disturbances of these rhythms, mainly of wake/sleep, hormonal secretion and feeding, cause decrease in quality of life, as well as being involved in development of obesity, metabolic syndrome and neuropsychiatric disorders. Most immunological functions, from leukocyte numbers, activity and cytokine secretion undergo circadian variations, which might affect susceptibility to infections. The intensity of symptoms and disease severity show a 24 h pattern in many immunological and allergic diseases, including rheumatoid arthritis, bronchial asthma, atopic eczema and chronic urticaria. This is accompanied by altered sleep duration and quality, a major determinant of quality of life. Shift work and travel through time zones as well as artificial light pose new health threats by disrupting the circadian rhythms. Finally, the field of chronopharmacology uses these concepts for delivering drugs in synchrony with biological rhythms
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
Inhibitory effect of quercetin on tryptase and interleukin-6 release, and histidine decarboxylase mRNA transcription by human mast cell-1 cell line
No full textMast cells are involved in inflammatory processes and in allergic reactions where immunologic stimulation leads to degranulation and generation of numerous cytokines and inflammatory mediators. Mast cells have been proposed as an immune gate to the brain, as well as sensors of environmental and emotional stress, and are likely involved in neuropathologic processes such as multiple sclerosis. Among mast cell products, the protease tryptase could be associated with neurodegenerative processes through the activation of specific receptors (PARs) expressed in the brain, while interleukin (IL)-6 likely causes neurodegeneration and exacerbates dysfunction induced by other cytokines; or it could have a protective effect against demyelinisation. In this report we show that quercetin, a natural compound able to act as an inhibitor of mast cell secretion, causes a decrease in the release of tryptase and IL-6 and the down-regulation of histidine decarboxylase (HDC) mRNA from human mast cell (HMC)-1 cells. As quercetin dramatically inhibits mast cell tryptase and IL-6 release and HDC mRNA transcription by HMC-1 cell line, these results nominate quercetin as a therapeutical compound in association with other therapeutical molecules for neurological diseases mediated by mast cell degranulation
Exposure to sub-10 nm particles emitted from a biodiesel-fueled diesel engine: In vitro toxicity and inflammatory potential
No full textObjectives: The inflammatory effects of organic sub-10 nm particles generated and emitted from a diesel
engine fueled with a biodiesel and a commercial diesel oil are analyzed in this paper. Diesel combustion is
the major sources of ultrafine particles (UFP) in the environment, particularly in urbanized areas. In the
last years, there is an increasing use of biomass-derived fuels because they are a renewable source of
energy that may mitigate climate change through the reduction of net CO2 with respect to conventional
fossil fuels. Although there is a general agreement on biofuels ability to reduce conventional pollutants,
new and potentially harmful pollutants can be formed during biofuel combustion. In particular, the
emission of sub-10 nm particles is strongly increased with respect to that of larger soot particles.
Methods: Organic sub-10 nm particles are separated from larger sizes particulate matter by collection in
water suspension for toxicological and inflammatory tests. After exposure to sub-10 nm particles, the
effects on proliferation, apoptosis and secretion of cytokines, chemokines and growth factors networks
production is analyzed in immortalized non-tumorigenic human dermal keratinocyte cell line (HaCaT)
and human alveolar epithelial-like cells (A549).
Results and conclusion: Nanoparticles exert different cytotoxic effects in the two cell lines, suggesting that
the dermal way of exposure is more sensitive than the inhalant way. These differences are most evident in
the secretion of pro-inflammatory, angiogenic and proliferative cytokines and chemokines whose
expression is more finely modulated in HaCaT cells compared to A-549 cells. Considering the size of these
particles, it is important to promote the culture of prevention also for the dermal way in particularly
exposed workers
Rat basophilic leukemia cells (RBL-2H3) generate prostaglandin D2 (PGD2) after regulated upon activation, normal T-cell expressed and secreted (RANTES) activation.
No full textIncreasing evidence indicates that local neurogenic inflammation, possibly in response to different stimuli, may be involved in sensory nerve sensitization, migraine generation and some other precipitating events leading to neuronal dysfunction in the brain. In addition, mast cells generate eicosanoids that are linked to asthma and other inflammatory diseases. Regulated upon activation, normal T-cell expressed and secreted (RANTES) is a small protein and a prototype member of the CC chemokine-beta subfamily with chemoattractant and inflammatory properties. In this study we used the RBL-2H3 cell line to determine whether or not these cells generate prostaglandin D2 (PGD2) after treatment with RANTES. After 4 hours of incubation, RBL-2H3 cells cultured with RANTES at 20 ng/mL released large amounts of PGD2 in a dose-response manner compared to control. Moreover, RBL-treated RANTES generated a large quantity of histamine. Our study confirms once again the proinflammatory action of RANTES, in this case acting on the stimulation of the arachidonic acid cascade product PGD2
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
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