346 research outputs found

    Simultaneous expression of Oct4 and genes of three germ layers in single cell-derived multipotent adult progenitor cells

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    Future application of adult stem cells in clinical therapies largely depends on the successful isolation of homogeneous stem cells with high plasticity. Multipotent adult progenitor cells (MAPCs) are thought to be a more primitive stem cell population capable of extensive in vitro proliferation with no senescence or loss of differentiation capability. The present study was aimed to find a less complicated and more economical protocol for obtaining single cell-derived MAPCs and understand the molecule mechanism of multi-lineage differentiation of MAPCs. We successfully obtained a comparatively homogeneous population of MAPCs and confirmed that single cell-derived MAPCs were able to transcribe Oct4 and genes of three germ layers simultaneously, and differentiate into multiple lineages. Our observations suggest that single cell-derived MAPCs under appropriate circumstances could maintain not only characteristics of stem cells but multi-lineage differentiation potential through quantitative modulation of corresponding regulating gene expression, rather than switching on expression of specific genes

    W18O49 Nanowires as Ultraviolet Photodetector

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    Photodetectors in a configuration of field effect transistor were fabricated based on individual W18O49 nanowires. Evaluation of electrical transport behavior indicates that the W18O49 nanowires are n-type semiconductors. The photodetectors show high sensitivity, stability and reversibility to ultraviolet (UV) light. A high photoconductive gain of 104 was obtained, and the photoconductivity is up to 60 nS upon exposure to 312 nm UV light with an intensity of 1.6 mW/cm2. Absorption of oxygen on the surface of W18O49 nanowires has a significant influence on the dark conductivity, and the ambient gas can remarkably change the conductivity of W18O49 nanowire. The results imply that W18O49 nanowires will be promising candidates for fabricating UV photodetectors

    Sex-based differences in risk of ischaemic stroke or systemic embolism after BNT162b2 or CoronaVac COVID-19 vaccination in patients with atrial fibrillation: a self-controlled case series and nested case-control study

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    AIMS: Patients with atrial fibrillation (AF) have a higher risk of ischemic stroke or systemic embolism with a greater risk for female patients. This study aims to evaluate the risk of ischemic stroke or systemic embolism and bleeding following COVID-19 vaccination in patients with AF and the sex differences. METHODS AND RESULTS: Self-controlled case series (SCCS) analysis was conducted to evaluate the risk of ischemic stroke or systemic embolism and bleeding following BNT162b2 or CoronaVac in patients with AF, using the territory-wide electronic medical records from the Hospital Authority and vaccination records from the Department of Health in Hong Kong. Patients with a primary diagnosis of ischemic stroke or systemic embolism or bleeding in the inpatient setting between February 23, 2021 and March 31, 2022 were included. A nested case-control analysis was also conducted with each case randomly matched with ten controls according to sex, age, Charlson comorbidity index and date of hospital admission. Conditional Poisson regression was used in the SCCS analysis and conditional logistic regression was used in nested case-control analysis to assess the risks and all analyses were stratified by sex and type of vaccines. Among 51 158 patients with AF, we identified an increased risk of ischemic stroke or systemic embolism after the first dose of BNT162b2 in SCCS analysis during 0-13 days (incidence rate ratio 6.60[95% CI 1.51-28.77]) and 14-27 days (6.53[95% CI 1.31-32.51]), and nested case-control analysis during 0-13 days (adjusted odds ratio 6.21 [95% CI 1.14-33.91]) and 14-27 days (5.52 [95% CI 1.12-27.26]) only in female patients. The increased risk in female patients following the first dose of CoronaVac was only detected during 0-13 days (3.88 [95% CI 1.67-9.03]) in the nested case-control analysis. No increased risk of ischemic stroke or systemic embolism was identified in male patients and no increased risk of bleeding was detected in all patients with AF for both vaccines. An increased risk of ischemic stroke or systemic embolism after COVID-19 was also observed in both females (17.42 [95% CI 5.08-59.73]) and males (6.63 [95% CI 2.02-21.79]). CONCLUSIONS: The risk of ischemic stroke or systemic embolism after COVID-19 vaccination was only increased in female patients with AF. However, as the risk after COVID-19 was even higher, proactive uptake of COVID-19 vaccines is recommended to prevent the potential severe outcomes after infection

    Positional Signaling and Expression of ENHANCER OF TRY AND CPC1 Are Tuned to Increase Root Hair Density in Response Phosphate Deficiency in Arabidopsis thaliana

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    Phosphate (Pi) deficiency induces a multitude of responses aimed at improving the acquisition of Pi, including an increased density of root hairs. To understand the mechanisms involved in Pi deficiency-induced alterations of the root hair phenotype in Arabidopsis (Arabidopsis thaliana), we analyzed the patterning and length of root epidermal cells under control and Pi-deficient conditions in wild-type plants and in four mutants defective in the expression of master regulators of cell fate, CAPRICE (CPC), ENHANCER OF TRY AND CPC 1 (ETC1), WEREWOLF (WER) and SCRAMBLED (SCM). From this analysis we deduced that the longitudinal cell length of root epidermal cells is dependent on the correct perception of a positional signal (‘cortical bias’) in both control and Pi-deficient plants; mutants defective in the receptor of the signal, SCM, produced short cells characteristic of root hair-forming cells (trichoblasts). Simulating the effect of cortical bias on the time-evolving probability of cell fate supports a scenario in which a compromised positional signal delays the time point at which non-hair cells opt out the default trichoblast pathway, resulting in short, trichoblast-like non-hair cells. Collectively, our data show that Pi-deficient plants increase root hair density by the formation of shorter cells, resulting in a higher frequency of hairs per unit root length, and additional trichoblast cell fate assignment via increased expression of ETC1

    Transgenic Cry1Ab Rice Does Not Impact Ecological Fitness and Predation of a Generalist Spider

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    Background: The commercial release of rice genetically engineered to express a Cry1Ab protein from Bacillus thuringiensis (Bt) for control of Lepidoptera in China is a subject of debate. One major point of the debate has focused on the ecological safety of Bt rice on nontarget organisms, especially predators and parasitoids that help control populations of insect pests. Methodology/Principal Findings: A tritrophic bioassay was conducted to evaluate the potential impact of Cry1Abexpressing rice on fitness parameters of a predaceous ground spider (Pardosa pseudoannulata (Bösenberg et Strand)) that had fed on Bt rice-fed brown planthopper (Nilaparvata lugens (Sta˚l)) nymphs. Survival, development time and fecundity of this spider were not different when they were fed with Bt rice-fed or non-Bt rice-fed prey. Furthermore, ELISA and PCR gut assays, as well as a functional response trial, indicated that predation by P. pseudoannulata was not significantly different in Bt rice or non-Bt rice fields. Conclusions/Significance: The transgenic Cry1Ab rice lines tested in this study had no adverse effects on the survival, developmental time and fecundity of P. pseudoannulata in the laboratory or on predation under field conditions. Thi

    Correlation of microarray-based breast cancer molecular subtypes and clinical outcomes: implications for treatment optimization

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    <p>Abstract</p> <p>Background</p> <p>Optimizing treatment through microarray-based molecular subtyping is a promising method to address the problem of heterogeneity in breast cancer; however, current application is restricted to prediction of distant recurrence risk. This study investigated whether breast cancer molecular subtyping according to its global intrinsic biology could be used for treatment customization.</p> <p>Methods</p> <p>Gene expression profiling was conducted on fresh frozen breast cancer tissue collected from 327 patients in conjunction with thoroughly documented clinical data. A method of molecular subtyping based on 783 probe-sets was established and validated. Statistical analysis was performed to correlate molecular subtypes with survival outcome and adjuvant chemotherapy regimens. Heterogeneity of molecular subtypes within groups sharing the same distant recurrence risk predicted by genes of the Oncotype and MammaPrint predictors was studied.</p> <p>Results</p> <p>We identified six molecular subtypes of breast cancer demonstrating distinctive molecular and clinical characteristics. These six subtypes showed similarities and significant differences from the Perou-Sørlie intrinsic types. Subtype I breast cancer was in concordance with chemosensitive basal-like intrinsic type. Adjuvant chemotherapy of lower intensity with CMF yielded survival outcome similar to those of CAF in this subtype. Subtype IV breast cancer was positive for ER with a full-range expression of HER2, responding poorly to CMF; however, this subtype showed excellent survival when treated with CAF. Reduced expression of a gene associated with methotrexate sensitivity in subtype IV was the likely reason for poor response to methotrexate. All subtype V breast cancer was positive for ER and had excellent long-term survival with hormonal therapy alone following surgery and/or radiation therapy. Adjuvant chemotherapy did not provide any survival benefit in early stages of subtype V patients. Subtype V was consistent with a unique subset of luminal A intrinsic type. When molecular subtypes were correlated with recurrence risk predicted by genes of Oncotype and MammaPrint predictors, a significant degree of heterogeneity within the same risk group was noted. This heterogeneity was distributed over several subtypes, suggesting that patients in the same risk groups require different treatment approaches.</p> <p>Conclusions</p> <p>Our results indicate that the molecular subtypes established in this study can be utilized for customization of breast cancer treatment.</p

    Spatiotemporal cluster patterns of hand, foot, and mouth disease at the county level in Mainland China, 2008-2012

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    Background: Hand, foot, and mouth disease (HFMD) is known to be a highly contagious childhood illness. In recent years, the number of reported cases of HFMD has significantly increased in mainland China. This study aims at the epidemiological features, spatiotemporal patterns of HMFD at the county/district level in mainland China. Methods: Data on reported HFMD cases for each county from 1 January 2008 to 31 December 2012 were obtained from the Chinese Center for Disease Control and Prevention. Cluster analysis, spatial autocorrelation, and retrospective scan methods were used to explore the spatiotemporal patterns of the disease. Results: The annual incidences varied greatly among the counties, ranging from 0 to 74.31‰with the median of 5.42‰ (interquartile range: 1.54‰–13.55‰) during 2008–2012 in mainland China. Counties close to provincial capital cities generally had higher incidences than rural counties. A seasonal distribution was observed between the northern and southern China, of which dual epidemic were shown in southern China and usually only one in northern China. Based on the global and local spatial autocorrelation analysis, we found that the spatial distribution of HFMD was presented a significant clustering pattern for each year (P \u3c 0.001), and hotspots of the disease were mostly distributed in coastal provinces of China. The retrospective scan statistic further identified the dynamics of spatiotemporal clustering areas of the disease, which were mainly distributed in the counties of eastern and southern China, as well as provincial capitals and their surrounding counties. Conclusions: The spatiotemporal clustering areas of the disease identified in this way were relatively stable, and imminent public health planning and resource allocation should be focused within those areas

    Visible Light Responsive Photocatalyst Induces Progressive and Apical-Terminus Preferential Damages on Escherichia coli Surfaces

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    BACKGROUND: Recent research shows that visible-light responsive photocatalysts have potential usage in antimicrobial applications. However, the dynamic changes in the damage to photocatalyzed bacteria remain unclear. METHODOLOGY/PRINCIPAL FINDINGS: Facilitated by atomic force microscopy, this study analyzes the visible-light driven photocatalyst-mediated damage of Escherichia coli. Results show that antibacterial properties are associated with the appearance of hole-like structures on the bacteria surfaces. Unexpectedly, these hole-like structures were preferentially induced at the apical terminus of rod shaped E. coli cells. Differentiating the damages into various levels and analyzing the percentage of damage to the cells showed that photocatalysis was likely to elicit sequential damages in E. coli cells. The process began with changing the surface properties on bacterial cells, as indicated in surface roughness measurements using atomic force microscopy, and holes then formed at the apical terminus of the cells. The holes were then subsequently enlarged until the cells were totally transformed into a flattened shape. Parallel experiments indicated that photocatalysis-induced bacterial protein leakage is associated with the progression of hole-like damages, further suggesting pore formation. Control experiments using ultraviolet light responsive titanium-dioxide substrates also obtained similar observations, suggesting that this is a general phenomenon of E. coli in response to photocatalysis. CONCLUSION/SIGNIFICANCE: The photocatalysis-mediated localization-preferential damage to E. coli cells reveals the weak points of the bacteria. This might facilitate the investigation of antibacterial mechanism of the photocatalysis
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