3,496 research outputs found

    Natural killer cells and innate lymphoid cells but not NKT cells are mature in their cytokine production at birth.

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    Early life is a time of increased susceptibility to infectious diseases and development of allergy. Innate lymphocytes are crucial components of the initiation and regulation of immune responses at mucosal surfaces, but functional differences in innate lymphocytes early in life are not fully described. We aimed to characterise the abundance and function of different innate lymphocyte cell populations in cord blood in comparison to that of adults. Blood was collected from adult donors and umbilical vessels at birth. Multicolour flow cytometry panels were used to identify and characterise lymphocyte populations and their capacity to produce hallmark cytokines. Lymphocytes were more abundant in cord blood compared to adults, however, mucosal-associated invariant T (MAIT) cells and Natural Killer T (NKT)-like cells, were far less abundant. The capacity of NKT-like cells to produce cytokines and their expression of the cytotoxic granule protein granzyme B and the marker of terminal differentiation CD57 were much lower in cord blood than in adults. In contrast, Natural Killer (NK) cells were as abundant in cord blood as in adults, they could produce IFNγ, and their expression of granzyme B was not significantly different to that of adult NK cells, although CD57 expression was lower. All innate lymphoid cell (ILC) subsets were more abundant in cord blood, and ILC1 and ILC2 were capable of production of IFNγ and IL-13, respectively. In conclusion, different innate lymphoid cells differ in both abundance and function in peripheral blood at birth and with important implications for immunity in early life

    Influence of floodwater irrigation on vegetation composition and vegetation regeneration in a Taklimakan desert oasis

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    Naturally occurring floods in the summer months are the main source of surface water application in the foreland of Qira oasis, which is characterized by a hyperarid climate and is located at the southern fringe of the Taklimakan Desert. We investigated the impact of repeated artificial flood irrigation on seedling recruitment and growth of Alhagi sparsifolia and Karelinia caspica plant communities which are part of the dominant vegetation in Qira oasis. Flood irrigation was applied three times during the growing season and we studied the effect of irrigation on species recruitment, vegetation growth, species composition, and changes in soil water and nutrient concentrations in the soil profile. Results show that (1) repeated flood irrigation had a positive effect on seedling recruitment of the two species, with vegetative recruitment via root tillers being more important than seed recruitment for both species. (2) Irrigation promoted the germination and establishment of herbaceous weed species, which increased species diversity as well as ground coverage. (3) Irrigation also increased soil water and soil nutrient concentrations in the upper soil layer and changed the soil nutrients in the vertical profile. Available N, P, K and the total P and K increased in the soil profile. Our study demonstrates that naturally occurring flood irrigation has significant ecological benefits and plays an important role in promoting the renewal of desert vegetation and a short-term increase of soil nutrients. Our study also highlights the potential negative consequences for vegetation composition and rejuvenation if naturally occurring floods in the study area are diminished by either the effects of climate change or human management

    Growth, physiological characteristics and ion distribution of NaCl stressed Alhagi sparsifolia seedlings

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    Alhagi sparsifolia is a leguminous perennial desert species that is plays an important role in dune stabilization and revegetation of degraded desert ecosystems. We investigated the effects of three different levels of salinity (50, 150, 250 mmol/L NaCl) on the growth, shoot photosynthetic parameters and salt distribution amongst different plant organs in one-year-old A. sparsifolia seedlings in a pot experiment over a 50 d period. The minimum (predawn) and maximum (midday) water potentials of A. sparsifolia seedlings decreased with the increase of external NaCl concentrations as a consequence of the osmotic or water deficit effect of saline solutions outside the roots. Salinity also reduced gas exchange parameters in A. sparsifolia, with seedlings subjected to salinity having lower photosynthesis rates and reduced stomatal conductances compared to the control. The reductions in photosynthetic rates in high salinity treatments of the A. sparsifolia seedlings were mainly caused by stomatal limitation. Consequently plants growing at greater external NaCl concentrations had significantly lower biomass accumulation compared to the control grown at 50 mmol/L. However, plants exposed to higher salinity were able to maintain growth throughout the experiment but allocated a greater proportion of biomass belowground. Plants exposed to higher external salinity levels had increased concentrations of Na+ and Cl- ions in shoots and roots, suggesting that A. sparsifolia seedlings were utilizing Na+ and Cl- as osmolytes to increase the cellular osmolality and decrease their water potential. We observed the greatest NaCl concentrations in the plants treated with 150 mmol/L NaCl indicating that there may be a threshold level of NaCl that can be tolerated by the plants. In conclusion our results indicate that A. sparsifolia seedlings are moderately salt tolerant. Photosynthetic gas exchange parameters were reduced by greater external salinity but the seedlings maintained substantial photosynthetic rates even under high salinity stress, were able to maintain growth over the 50 d experimental period and showed no signs of salinity toxicity or damage

    Modelling Future Coronary Heart Disease Mortality to 2030 in the British Isles.

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    OBJECTIVE: Despite rapid declines over the last two decades, coronary heart disease (CHD) mortality rates in the British Isles are still amongst the highest in Europe. This study uses a modelling approach to compare the potential impact of future risk factor scenarios relating to smoking and physical activity levels, dietary salt and saturated fat intakes on future CHD mortality in three countries: Northern Ireland (NI), Republic of Ireland (RoI) and Scotland. METHODS: CHD mortality models previously developed and validated in each country were extended to predict potential reductions in CHD mortality from 2010 (baseline year) to 2030. Risk factor trends data from recent surveys at baseline were used to model alternative future risk factor scenarios: Absolute decreases in (i) smoking prevalence and (ii) physical inactivity rates of up to 15% by 2030; relative decreases in (iii) dietary salt intake of up to 30% by 2030 and (iv) dietary saturated fat of up to 6% by 2030. Probabilistic sensitivity analyses were then conducted. RESULTS: Projected populations in 2030 were 1.3, 3.4 and 3.9 million in NI, RoI and Scotland respectively (adults aged 25-84). In 2030: assuming recent declining mortality trends continue: 15% absolute reductions in smoking could decrease CHD deaths by 5.8-7.2%. 15% absolute reductions in physical inactivity levels could decrease CHD deaths by 3.1-3.6%. Relative reductions in salt intake of 30% could decrease CHD deaths by 5.2-5.6% and a 6% reduction in saturated fat intake might decrease CHD deaths by some 7.8-9.0%. These projections remained stable under a wide range of sensitivity analyses. CONCLUSIONS: Feasible reductions in four cardiovascular risk factors (already achieved elsewhere) could substantially reduce future coronary deaths. More aggressive polices are therefore needed in the British Isles to control tobacco, promote healthy food and increase physical activity

    Cross-sectional comparisons of sodium content in processed meat and fish products among five countries: potential for feasible targets and reformulation.

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    INTRODUCTION: Reducing sodium intake has been identified as a highly cost-effective strategy to prevent and control high blood pressure and reduce cardiovascular mortality. This study aims to compare the sodium content in processed meat and fish products among five countries, which will contribute to the evidence-base for feasible strategies of sodium reduction in such products. METHODS: Sodium content on product labels of 26 500 prepackaged products, 19 601 meat and 6899 fish, was collected in supermarkets from five countries using the FoodSwitch mobile application from 2012 to 2018. To be specific, it was 1898 products in China, 885 in the UK, 5673 in Australia, 946 in South Africa and 17 098 in the USA. Cross-sectional comparisons of sodium levels and proportions meeting 2017 UK sodium reduction targets were conducted using Kruskal-Wallis H and the χ2 test, respectively across the five countries. RESULTS: The results showed that processed meat and fish products combined in China had the highest sodium level (median 1050 mg/100 g, IQR: 774-1473), followed by the USA, South Africa, Australia, with the lowest levels found in UK (432 mg/100 g, IQR: 236-786) (p<0.001). Similar variations, that is, a twofold to threefold difference of sodium content between the highest and the lowest countries were found among processed meat and fish products separately. Large sodium content variations were also found in certain specific food subcategories across the five countries, as well as across different food subcategories within each country. CONCLUSION: Processed meat and fish products differ greatly in sodium content across different countries and across different food subcategories. This indicates great potential for food producers to reformulate the products in sodium content, as well as for consumers to select less salted food

    Gravitational collapse with tachyon field and barotropic fluid

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    A particular class of space-time, with a tachyon field, \phi, and a barotropic fluid constituting the matter content, is considered herein as a model for gravitational collapse. For simplicity, the tachyon potential is assumed to be of inverse square form i.e., V(\phi) \sim \phi^{-2}. Our purpose, by making use of the specific kinematical features of the tachyon, which are rather different from a standard scalar field, is to establish the several types of asymptotic behavior that our matter content induces. Employing a dynamical system analysis, complemented by a thorough numerical study, we find classical solutions corresponding to a naked singularity or a black hole formation. In particular, there is a subset where the fluid and tachyon participate in an interesting tracking behaviour, depending sensitively on the initial conditions for the energy densities of the tachyon field and barotropic fluid. Two other classes of solutions are present, corresponding respectively, to either a tachyon or a barotropic fluid regime. Which of these emerges as dominant, will depend on the choice of the barotropic parameter, \gamma. Furthermore, these collapsing scenarios both have as final state the formation of a black hole.Comment: 18 pages, 7 figures. v3: minor changes. Final version to appear in GR

    Genetic Polymorphisms of CYP2E1, GSTP1, NQO1 and MPO and the Risk of Nasopharyngeal Carcinoma in a Han Chinese Population of Southern China

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    <p>Abstract</p> <p>Background</p> <p>Southern China is a major area for endemic nasopharyngeal carcinoma (NPC). Genetic factors as well as environmental factors play a role in development of NPC. To investigate the roles of previously described carcinogen metabolism gene variants for NPC susceptibility in a Han Chinese population, we conducted a case-control study in two independent study population groups afflicted with NPC in Guangdong and Guangxi Provinces of southern China.</p> <p>Methods</p> <p>Five single nucleotide polymorphisms (SNPs) of <it>CYP2E1</it>-rs2031920, <it>CYP2E1</it>-rs6413432, <it>GSTP1</it>-rs947894, <it>MPO</it>-rs2333227 and <it>NQO1</it>-rs1800566 were genotyped by PCR-based RFLP, sequencing and TaqMan assay in 358 NPC cases and 629 controls (phase I cohort). Logistic regression analysis was used to estimate odds ratios (OR) and 95% confidence intervals (CI). To confirm our results, sixteen tag SNPs for <it>GSTP1</it>, <it>MPO</it>, <it>NQO1 </it>(which 100% covered these genes), and 4 functional SNPs of <it>CYP2E1 </it>were genotyped in another cohort of 213 NPC cases and 230 controls (phase II cohort).</p> <p>Results</p> <p>No significant associations in NPC risk were observed for the five polymorphisms tested in the phase I cohort. In an additional stratified analysis for phase I, there was no significant association between cases and controls in NPC high risk population (EBV/IgA/VCA positive population). Analysis of 14 tagging SNPs within the same genes in an independent phase II cohort were in agreement with no SNPs significantly associated with NPC.</p> <p>Conclusions</p> <p>Our results suggest that polymorphism of <it>CYP2E1</it>, <it>GSTP1</it>, <it>MPO </it>and <it>NQO1 </it>genes does not contribute to overall NPC risk in a Han Chinese in southern China.</p

    Expression of BMI-1 and Mel-18 in breast tissue - a diagnostic marker in patients with breast cancer

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    <p>Abstract</p> <p>Background</p> <p>Polycomb Group (PcG) proteins are epigenetic silencers involved in maintaining cellular identity, and their deregulation can result in cancer. Expression of Mel-18 and Bmi-1 has been studied in tumor tissue, but not in adjacent non-cancerous breast epithelium. Our study compares the expression of the two genes in normal breast epithelium of cancer patients and relates it to the level of expression in the corresponding tumors as well as in breast epithelium of healthy women.</p> <p>Methods</p> <p>A total of 79 tumors, of which 71 malignant tumors of the breast, 6 fibroadenomas, and 2 DCIS were studied and compared to the reduction mammoplastic specimens of 11 healthy women. In addition there was available adjacent cancer free tissue for 23 of the malignant tumors. The tissue samples were stored in RNAlater, RNA was isolated to create expression microarray profile. These two genes were then studied more closely first on mRNA transcription level by microarrays (Agilent 44 K) and quantitative RT-PCR (TaqMan) and then on protein expression level using immunohistochemistry.</p> <p>Results</p> <p>Bmi-1 mRNA is significantly up-regulated in adjacent normal breast tissue in breast cancer patients compared to normal breast tissue from noncancerous patients. Conversely, mRNA transcription level of Mel-18 is lower in normal breast from patients operated for breast cancer compared to breast tissue from mammoplasty. When protein expression of these two genes was evaluated, we observed that most of the epithelial cells were positive for Bmi-1 in both groups of tissue samples, although the expression intensity was stronger in normal tissue from cancer patients compared to mammoplasty tissue samples. Protein expression of Mel-18 showed inversely stronger intensity in tissue samples from mammoplasty compared to normal breast tissue from patients operated for breast cancer.</p> <p>Conclusion</p> <p>Bmi-1 mRNA level is consistently increased and Mel-18 mRNA level is consistently decreased in adjacent normal breast tissue of cancer patients as compared to normal breast tissue in women having had reduction mammoplasties. Bmi-1/Mel-18 ratio can be potentially used as a tool for stratifying women at risk of developing malignancy.</p
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