1,721,045 research outputs found
E-cigarettes induce toxicological effects that can raise the cancer risk. A frame from drug-metabolism and antioxidant homeostasis
No full textE-CIGARETTES INDUCE TOXICOLOGICAL EFFECTS THAT CAN RAISE THE CANCER RISK. A FRAME
FROM DRUG-METABOLISM AND ANTIOXIDANT HOMEOSTASIS.
1)Canistro D. 2)Vivarelli F. 3)Cirillo S. 4)Cardenia V. 5)Rodriguez-estrada MT.
Dept of Pharmacy and Biotechnology, Unibo
Electronic cigarettes (e-cigs) are devices designed to deliver nicotine in a vaping solution without tobacco combustion. Perceived as a safer alternative to conventional cigarettes, e-cigs are aggressively marketed as lifestyle-choice consumables, thanks to few restrictions and a lack of regulatory guidelines. Despite the burgeoning worldwide consumption of e-cigs, their safety remains largely unproven and it is unknown whether these devices cause in vivo toxicological effects that could contribute to cancer occurrence.
In the present study, we investigated the co-mutagenic and cancer-initiating effects of e-cig vapour in a rat model. To explore whether e-cigs induce toxicological effects, such as those involving cytochrome P450 (CYP) changes, we analyzed the modulation of carcinogen metabolizingenzymes in the lung of rats exposed to e-cig vapour. We observed a significant increase in CYP1A1/2 (activating, for example, polychlorinated biphenyls, aromatic amines, dioxins and PAHs), CYP2B1/2 (activating olefins and halogenated hydrocarbons), 2C11 (activating nitrosamines and mycotoxins) and CYP3A (activating hexamethyl phosphoramide and nitrosamines) documented by the sharp rise in the corresponding probes.
Conversely, we observed that the antioxidant enzymes catalase, DT-diaphorase and glutathione peroxidase and the conjugating phase II glutathione S-transferases, mainly involved in xenobiotic detoxification, were noticeable decreased, whereas UDP-glucuronyl-transferase was substantially unchanged.
Extrapolated to humans, the corresponding boosted CYP-linked monooxygenases together with reduced activity of antioxidant and detoxifying machinery would predispose a subject to an enhanced cancer risk from the widely bioactivated e-cig vapour procarcinogens associated with an increased risk of lung cancer
Cholesterol photosensitized oxidation in muscle foods
No full textCholesterol photoxidation can affect the nutritional quality of fresh meat and fish due to the formation of
cholesterol oxidation products (COPs), which exert a strong impact on the lipid metabolism and are
involved in various chronic and degenerative diseases and disturbance of cell functionality. The
evaluation of light sensitized cholesterol oxidation has been reviewed in beef, pork, horse, turkey,
and sardine muscle. In the retail market, fresh slices of meat or fish are usually displayed in
refrigerated vessels wrapped with plastic film and are exposed to a fluorescent light. Under these
conditions, COPs can range from 8.5 mg/g of lipids (photoxidized pork meat) to more than 300 mg/g
of lipids (photoxidized horse meat), corresponding to a maximum of 1.3% of oxidized cholesterol. The
oxidative process can be reduced by feeding the animals with antioxidants, such as tocopherols, or by
spraying the muscle food with lipid- or water-soluble antioxidants before packaging. However, the
combined use of alternative protective packaging and lighting conditions during commercial retail
storage, such as the use of red wrapping films, warm tone lamps, and modified atmosphere with low
oxygen content, can efficiently prevent photoxidation without modifying the food product composition
and sensory propertie
Nutraceuticals and physical activity: Their role on oxysterols-mediated neurodegeneration
Full text linkOver the past few years, the contribution of oxysterols to the onset and development of some of the major neurodegenerative diseases (such as Alzheimer’s and Parkinson’s diseases) has been scientifically asserted, being mainly related to altered brain cholesterol homeostasis. To counteract oxysterol induced inflammation at neuronal level, one possible intervention approach is the administration of some nutrients and/or plant secondary metabolites. On the other hand, the pleiotropic beneficial effects of physical activity seem to play an important role on prevention and counteraction of neurodegenerative diseases, through the modulation of oxysterol homeostasis and the prevention of demyelination. The present review provides a picture of the promising role of nutraceuticals and physical activity on oxysterol-mediated neurodegeneration, pointing out also the different in vitro and in vivo aspects that need to be further investigated for a better understanding of the association of these three counterparts and their overall effect on people at increased risk for neurodegenerative diseases
New insights on phytocannabinoids role in antioxidant activity of hemp inflorescences extract in high-oleic sunflower oil
Full text linkHemp (Cannabis sativa L.) inflorescences contain bioactive compounds potentially able to counteract lipid oxidation in vegetable oils. In this study, two hemp inflorescences extracts with (E) and without (wE) phytocannabinoids were tested at 0.02, 1.0, and 2.0 g/100 g of high-oleic sunflower oil (HOSO) exposed to thermo-oxidative conditions (90 °C; pO2, 600 KPa). Immediately at the end of induction time, the oxidative stability index (OSI), peroxide value (PV), main lipid classes, phytosterols, phytosterols oxidation products (POPs) content, and volatile organic compounds were determined. E extract added at 2.0 g/100 g proved to be more effective than wE extract, extending the OSI by almost 30 % with respect to control. The lowest PV (p < 0.01) was observed in the oil containing E (2.0 g/100 g), which also proved to significantly reduce the POPs content (p < 0.05). Both extracts had no effect on lipolysis during the entire experiment. The principal component analysis highlighted different antioxidant activity related to both type of extract and their concentration. These results suggest that hemp inflorescences could be a source of natural preservatives for vegetable oils even under severe oxidative conditions and confirm that phytocannabinoids play a key role in the modulation of antioxidant activity
Impairment of testicular function in electronic cigarette (e-cig, e-cigs) exposed rats under low-voltage and nicotine-free conditions
No full textDespite the lack of knowledge of the effects of electronic cigarettes (e-cigarettes, e-cigs) on public health, they have been proposed as a part of smoking cessation efforts. Recently, several basic scientific studies have pointed out how e-cigs can generate carcinogens, such as e-cig liquid thermal degradation by-products, and how the exposure can lead to genomic damage through inhibiting DNA repair or disrupting the redox homeostasis. However, scientific studies have pointed out how e-cigs can generate carcinogens and their release could be avoided setting the device to a low-voltage regimen. To test this feasibility, we show the effects of e-cig vapour generated from a low-voltage device filled with a nicotine-free liquid on rat testicular functions. The chemical analysis revealed the presence of carbonyls, such as formaldehyde, acetaldehyde and acrolein. Rats exposed reported a lower relative testis weight and higher levels of lactate dehydrogenase (LDH) as tissue damage marker, along with an impairment of 3β-hydroxysteroid dehydrogenase (3β-HSD), 17β-hydroxysteroid dehydrogenase (17β-HSD) and glucose-6-phosphate dehydrogenase (G6PDH) as key enzymes in the steroidogenesis pathway. The pro-oxidative environment was confirmed by the higher amount of reactive oxygen species (ROS), the development of lipid peroxidation and protein carbonylation, as well as from the disruption of antioxidant capability. Finally, we observed a higher rate of DNA unwinding in white blood cell line and boosted lipoxygenase (LOX)-linked activity, a tumour promotion marker. Even with the device setting at weak conditions, our results if extrapolated to humans suggest that exposure to e-cig vapours might alter gonads function in male vapers
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
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