413 research outputs found

    Does Adaptive Thermogenesis occur after weight loss in adults? A systematic review

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    Adaptive thermogenesis (AT) has been proposed to be a compensatory response that may resist weight loss(WL) and promote weight regain. This systematic review examined the existence of AT in adults after a period of negative energy balance with or without a weight stabilization phase. Studies published until May 15th, 2020 were identified from PubMed, Cochrane Library, EMBASE, MEDLINE, SCOPUS and Web of Science. Inclusion criteria included: statistically significant WL; observational with follow-up or experimental studies; age>18years; sample size≥10 participants; intervention period ≥1week; published in English; objective measures of total daily energy expenditure(TDEE), resting energy expenditure(REE) and sleeping energy expenditure(SEE). The systematic review was registered at PROSPERO(2020 CRD42020165348). A total of 33 studies comprising 2528 participants, were included. AT was observed in 27 out of 33 studies. Twenty-three studies showed significant values for AT for REE(82.8%), 4 studies for TDEE(80.0%) and 2 studies for SEE(100%). A large heterogeneity in the methods used to quantify AT and between subjects and among studies regarding the magnitude of WL and/or of AT was reported. Well-designed studies reported lower or non-significant values for AT. Overall, these findings suggest that although WL may lead to AT in some of the EE components, these values may be small or non-statistically significant when higher-quality methodological designs are used. Furthermore, AT seems to be attenuated, or non-existent, after periods of weight stabilization/neutral energy balance. Therefore, more high-quality studies are warranted not only to disclose the existence of AT, but to understand its clinical implications on weight management outcomes

    A HER2 selective theranostic agent for surgical resection guidance and photodynamic therapy

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    In many cancers early intervention involves surgical resection of small localised tumour masses. Inadequate resection leads to recurrence whereas overzealous treatment can lead to organ damage. This work describes production of a HER2 targeting antibody Fab fragment dual conjugated to achieve both real time near-infrared fluorescent imaging and photodynamic therapy. The use of fluorescence emission from a NIR-dye could be used to guide resection of tumour bulk, for example during endoscopic diagnosis for oesophago-gastric adenocarcinoma, this would then be followed by activation of the photodynamic therapeutic agent to destroy untreated localised areas of cancer infiltration and tumour infiltrated lymph nodes. This theranostic agent was prepared from the Fab fragment of trastuzumab initially by functional disulfide re-bridging and site-specific click reaction of a NIR-dye. This was followed by further reaction with a novel pre-activated form of the photosensitiser chlorin e6 with the exposed fragments' lysine residues. Specific binding of the theranostic agent was observed in vitro with a HER2 positive cell line and cellular near-infrared fluorescence was observed with flow cytometry. Specific photo-activity of the conjugates when exposed to laser light was observed with HER2 positive but not HER2 negative cell lines in vitro, this selectivity was not seen with the unconjugated drug. This theranostic agent demonstrates that two different photo-active functions can be coupled to the same antibody fragment with little interference to their independent activities

    Free Rhodium (II) citrate and rhodium (II) citrate magnetic carriers as potential strategies for breast cancer therapy

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    <p>Abstract</p> <p>Background</p> <p>Rhodium (II) citrate (Rh<sub>2</sub>(H<sub>2</sub>cit)<sub>4</sub>) has significant antitumor, cytotoxic, and cytostatic activity on Ehrlich ascite tumor. Although toxic to normal cells, its lower toxicity when compared to carboxylate analogues of rhodium (II) indicates Rh<sub>2</sub>(H<sub>2</sub>cit)<sub>4 </sub>as a promising agent for chemotherapy. Nevertheless, few studies have been performed to explore this potential. Superparamagnetic particles of iron oxide (SPIOs) represent an attractive platform as carriers in drug delivery systems (DDS) because they can present greater specificity to tumor cells than normal cells. Thus, the association between Rh<sub>2</sub>(H<sub>2</sub>cit)<sub>4 </sub>and SPIOs can represent a strategy to enhance the former's therapeutic action. In this work, we report the cytotoxicity of free rhodium (II) citrate (Rh<sub>2</sub>(H<sub>2</sub>cit)<sub>4</sub>) and rhodium (II) citrate-loaded maghemite nanoparticles or magnetoliposomes, used as drug delivery systems, on both normal and carcinoma breast cell cultures.</p> <p>Results</p> <p>Treatment with free Rh<sub>2</sub>(H<sub>2</sub>cit)<sub>4 </sub>induced cytotoxicity that was dependent on dose, time, and cell line. The IC<sub>50 </sub>values showed that this effect was more intense on breast normal cells (MCF-10A) than on breast carcinoma cells (MCF-7 and 4T1). However, the treatment with 50 μM Rh<sub>2</sub>(H<sub>2</sub>cit)<sub>4</sub>-loaded maghemite nanoparticles (Magh-Rh<sub>2</sub>(H<sub>2</sub>cit)<sub>4</sub>) and Rh<sub>2</sub>(H<sub>2</sub>cit)<sub>4</sub>-loaded magnetoliposomes (Lip-Magh-Rh<sub>2</sub>(H<sub>2</sub>cit)<sub>4</sub>) induced a higher cytotoxicity on MCF-7 and 4T1 than on MCF-10A (p < 0.05). These treatments enhanced cytotoxicity up to 4.6 times. These cytotoxic effects, induced by free Rh<sub>2</sub>(H<sub>2</sub>cit)<sub>4</sub>, were evidenced by morphological alterations such as nuclear fragmentation, membrane blebbing and phosphatidylserine exposure, reduction of actin filaments, mitochondrial condensation and an increase in number of vacuoles, suggesting that Rh<sub>2</sub>(H<sub>2</sub>cit)<sub>4 </sub>induces cell death by apoptosis.</p> <p>Conclusions</p> <p>The treatment with rhodium (II) citrate-loaded maghemite nanoparticles and magnetoliposomes induced more specific cytotoxicity on breast carcinoma cells than on breast normal cells, which is the opposite of the results observed with free Rh<sub>2</sub>(H<sub>2</sub>cit)<sub>4 </sub>treatment. Thus, magnetic nanoparticles represent an attractive platform as carriers in Rh<sub>2</sub>(H<sub>2</sub>cit)<sub>4 </sub>delivery systems, since they can act preferentially in tumor cells. Therefore, these nanopaticulate systems may be explored as a potential tool for chemotherapy drug development.</p

    A global meta-analysis of ecological effects from offshore marine artificial structures

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    AbstractMarine artificial structures (MAS), including oil and gas installations (O&amp;G) and offshore wind farms (OWFs), have a finite operational period. Selecting the most suitable decommissioning options when reaching end-of-life remains a challenge, in part because their effects are still largely undetermined. Whether decommissioned structures could act (sensu ‘function’) as artificial reefs (ARs) and provide desired ecological benefits is of particular interest. Here we use a meta-analysis approach of 531 effect sizes from 109 articles to assess the ecological effects of MAS, comparing O&amp;G and OWFs to shipwrecks and ARs, with a view to inform their decommissioning. This synthesis demonstrates that while MAS can bring ecological benefits, important idiosyncrasies exist, with differences emerging between MAS types, habitat types, taxa and ecological metrics. Notably, we find limited conclusive evidence that O&amp;G and OWFs would provide significant ecological benefits if decommissioned as ARs. We conclude that decommissioning options aimed at repurposing MAS into ARs may not provide the intended benefits.</jats:p

    Musical Chairs on Temperate Reefs: Species Turnover and Replacement Within Functional Groups Explain Regional Diversity Variation in Assemblages Associated With Honeycomb Worms

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    Reef-building species are recognized as having an important ecological role and as generally enhancing the diversity of benthic organisms in marine habitats. However, although these ecosystem engineers have a facilitating role for some species, they may exclude or compete with others. The honeycomb worm Sabellaria alveolata (Linnaeus, 1767) is an important foundation species, commonly found from northwest Ireland to northern Mauritania, whose reef structures increase the physical complexity of the marine benthos, supporting high levels of biodiversity. Local patterns and regional differences in taxonomic and functional diversity were examined in honeycomb worm reefs from 10 sites along the northeastern Atlantic to explore variation in diversity across biogeographic regions and the potential effects of environmental drivers. While taxonomic composition varied across the study sites, levels of diversity remained relatively constant along the European coast. Assemblages showed high levels of species turnover compared to differences in richness, which varied primarily in response to sea surface temperatures and sediment content, the latter suggesting that local characteristics of the reef had a greater effect on community composition than the density of the engineering species. In contrast, the functional composition of assemblages was similar regardless of taxonomic composition or biogeography, with five functional groups being observed in all sites and only small differences in abundance in these groups being detected. Functional groups represented primarily filter-feeders and deposit-feeders, with the notable absence of herbivores, indicating that the reefs may act as biological filters for some species from the local pool of organisms. Redundancy was observed within functional groups that may indicate that honeycomb worm reefs can offer similar niche properties to its associated assemblages across varying environmental conditions. These results highlight the advantages of comparing taxonomic and functional metrics, which allow identification of a number of ecological processes that structure marine communities.</jats:p
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