482 research outputs found

    Highway to heaven: mammary gland development and differentiation

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    In recent years, the mammary gland epithelium has been shown to be a mixture of differentiated cell populations in a hierarchical relationship with their stem and progenitor cells. However, the mechanisms that regulate their cellular differentiation processes are still unclear. The identification of genes that govern stem and progenitor cell expansion, or that determine daughter cell fate, will be of crucial interest for understanding breast cancer diversity and, ultimately, improving treatment. Two recent analyses have identified some of the key genes that regulate these processes, lighting up the highway to normal mammary gland development

    Hypertriglyceridaemia as a risk factor for critical care admission in acute pancreatitis: A prospective study

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    Background and aimsHypertriglyceridaemia is both a primary cause of acute pancreatitis and an epiphenomenon. This study aimed to define the associations between hypertriglyceridaemia and clinical outcomes in patients admitted with acute pancreatitis.MethodsThis single-centre prospective observational study included patients with a confirmed clinical, biochemical or radiological diagnosis of acute pancreatitis from August 2017 to September 2018. Baseline demographics, aetiology of pancreatitis, and fasting triglyceride concentrations were recorded and assessed against the surrogate markers of severity: admission to critical care, length of stay (LOS), readmission to hospital, and mortality.ResultsIn total, 304 patients with a mean ± SD age of 56.1 ± 19.7 years met the inclusion criteria. There were 217 (71.4%) patients with normotriglyceridaemia ([less than] 150 mg/dL or [less than] 1.7 mmol/L), 47 (15.5%) with mild hypertriglyceridaemia (150–199 mg/dL or 1.7–2.25 mmol/L) and 40 (13.2%) with moderate-to-severe hypertriglyceridaemia (≥200 mg/dL or >2.25 mmol/L). The underlying aetiologies of acute pancreatitis were gallstones (55%), alcohol (18%), idiopathic (15%), hypertriglyceridaemia (9%), iatrogenic (2%) and bile duct abnormalities (1%). Patients with hypertriglyceridaemia were younger than those with normotriglyceridaemia (p [less than] 0.05). On multivariate regression, moderate-to-severe hypertriglyceridaemia (OR 5.66, 95% CI: 1.87 to 17.19, p = 0.002) and an elevated C-reactive protein concentration ≥120 mg/L (OR 1.00, 95% CI: 1.00–1.01, p = 0.040) were associated with admission to critical care. Moderate-to-severe hypertriglyceridaemia was also associated with an increased LOS (p = 0.002) but not readmission (p = 0.752) or mortality (p = 0.069).ConclusionModerate-to-severe hypertriglyceridaemia in all aetiological causes of acute pancreatitis was predictive of admission to critical care and prolonged LOS but not readmission or mortality

    Layered zeolitic materials: an approach to designing versatile functional solids

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    Relevant layered zeolites have been considered in this perspective article from the point of view of the synthesis methodologies, materials characterization and catalytic implications, considering the unique physico-chemical characteristics of lamellar materials. The potential of layered zeolitic precursors to generate novel lamellar accessible zeolites through swelling, intercalation, pillarization, delamination and/ or exfoliation treatments is studied, showing the chemical, functional and structural versatility exhibited by layered zeolites. Recent approaches based on the assembly of zeolitic nanosheets which act as inorganic structural units through the use of dual structural directing agents, the selective modification of germanosilicates and the direct generation of lamellar hybrid organic inorganic aluminosilicates are also considered to obtain layered solids with well-defined functionalities. The catalytic applications of the layered zeolites are also highlighted, pointing out the high accessibility and reactivity of active sites present in the lamellar framework.The authors thank financial support to Spanish Government by Consolider-Ingenio MULTICAT CSD2009-00050, MAT2011-29020-C02-01 and Severo Ochoa Excellence Program SEV-2012-0267.Díaz Morales, UM.; Corma Canós, A. (2014). Layered zeolitic materials: an approach to designing versatile functional solids. Dalton Transactions. 43(27):10292-10316. https://doi.org/10.1039/c3dt53181cS10292103164327Mallouk, T. E., & Gavin, J. A. (1998). Molecular Recognition in Lamellar Solids and Thin Films. Accounts of Chemical Research, 31(5), 209-217. doi:10.1021/ar970038pSuslick, K. S., & Price, G. J. (1999). APPLICATIONS OF ULTRASOUND TO MATERIALS CHEMISTRY. Annual Review of Materials Science, 29(1), 295-326. doi:10.1146/annurev.matsci.29.1.295Du, X., Zhang, D., Gao, R., Huang, L., Shi, L., & Zhang, J. (2013). 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    Allele-specific disparity in breast cancer

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    Background In a cancer cell the number of copies of a locus may vary due to amplification and deletion and these variations are denoted as copy number alterations (CNAs). We focus on the disparity of CNAs in tumour samples, which were compared to those in blood in order to identify the directional loss of heterozygosity. Methods We propose a numerical algorithm and apply it to data from the Illumina 109K-SNP array on 112 samples from breast cancer patients. B-allele frequency (BAF) and log R ratio (LRR) of Illumina were used to estimate Euclidian distances. For each locus, we compared genotypes in blood and tumour for subset of samples being heterozygous in blood. We identified loci showing preferential disparity from heterozygous toward either the A/B-allele homozygous (allelic disparity). The chi-squared and Cochran-Armitage trend tests were used to examine whether there is an association between high levels of disparity in single nucleotide polymorphisms (SNPs) and molecular, clinical and tumour-related parameters. To identify pathways and network functions over-represented within the resulting gene sets, we used Ingenuity Pathway Analysis (IPA). Results To identify loci with a high level of disparity, we selected SNPs 1) with a substantial degree of disparity and 2) with substantial frequency (at least 50% of the samples heterozygous for the respective locus). We report the overall difference in disparity in high-grade tumours compared to low-grade tumours (p-value < 0.001) and significant associations between disparity in multiple single loci and clinical parameters. The most significantly associated network functions within the genes represented in the loci of disparity were identified, including lipid metabolism, small-molecule biochemistry, and nervous system development and function. No evidence for over-representation of directional disparity in a list of stem cell genes was obtained, however genes appeared to be more often altered by deletion than by amplification. Conclusions Our data suggest that directional loss and amplification exist in breast cancer. These are highly associated with grade, which may indicate that they are enforced with increasing number of cell divisions. Whether there is selective pressure for some loci to be preferentially amplified or deleted remains to be confirmed

    Pogostick: A New Versatile piggyBac Vector for Inducible Gene Over-Expression and Down-Regulation in Emerging Model Systems

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    Non-traditional model systems need new tools that will enable them to enter the field of functional genetics. These tools should enable the exploration of gene function, via knock-downs of endogenous genes, as well as over-expression and ectopic expression of transgenes.We constructed a new vector called Pogostick that can be used to over-express or down-regulate genes in organisms amenable to germ line transformation by the piggyBac transposable element. Pogostick can be found at www.addgene.org, a non-profit plasmid repository. The vector currently uses the heat-shock promoter Hsp70 from Drosophila to drive transgene expression and, as such, will have immediate applicability to organisms that can correctly interpret this promotor sequence. We detail how to clone candidate genes into this vector and test its functionality in Drosophila by targeting a gene coding for the fluorescent protein DsRed. By cloning a single DsRed copy into the vector, and generating transgenic lines, we show that DsRed mRNA and protein levels are elevated following heat-shock. When cloning a second copy of DsRed in reverse orientation into a flanking site, and transforming flies constitutively expressing DsRed in the eyes, we show that endogenous mRNA and protein levels drop following heat-shock. We then test the over-expression vector, containing the complete cDNA of Ultrabithorax (Ubx) gene, in an emerging model system, Bicyclus anynana. We produce a transgenic line and show that levels of Ubx mRNA expression rise significantly following a heat-shock. Finally, we show how to obtain genomic sequence adjacent to the Pogostick insertion site and to estimate transgene copy number in genomes of transformed individuals.This new vector will allow emerging model systems to enter the field of functional genetics with few hurdles

    Image-Based Assessment of Growth and Signaling Changes in Cancer Cells Mediated by Direct Cell-Cell Contact

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    Many important biological processes are controlled through cell-cell interactions, including the colonization of metastatic tumor cells and the control of differentiation of stem cells within their niche. Despite the crucial importance of the cellular environment in regulating cellular signaling, in vitro methods for the study of such interactions are difficult and/or indirect.We report on the development of an image-based method for distinguishing two cell types grown in coculture. Furthermore, cells of one type that are in direct contact with cells of a second type (adjacent cells) can be analyzed separately from cells that are not within a single well. Changes are evaluated using population statistics, which are useful in detecting subtle changes across two populations. We have used this system to characterize changes in the LNCaP prostate carcinoma cell line when grown in contact with human vascular endothelial cells (HUVECs). We find that the expression and phosphorylation of WWOX is reduced in LNCaP cells when grown in direct contact with HUVECs. Reduced WWOX signaling has been associated with reduced activation or expression of JNK and p73. We find that p73 levels are also reduced in LNCaP cells grown in contact with HUVECs, but we did not observe such a change in JNK levels.We find that the method described is statistically robust and can be adapted to a wide variety of studies where cell function or signaling are affected by heterotypic cell-cell contact. Ironically, a potential challenge to the method is its high level of sensitivity is capable of classifying events as statistically significant (due to the high number cells evaluated individually), when the biological effect may be less clear. The methodology would be best used in conjunction with additional methods to evaluate the biological role of potentially subtle differences between populations. However, many important events, such as the establishment of a metastatic tumor, occur through rare but important changes, and methods such as we describe here can be used to identify and characterize the contribution of the environment to these changes

    10 Anos da Participação Portuguesa na IFOR

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    Seminário aberto ao público, realizado no Instituto da Defesa Nacional no dia 5 de Abril de 2006. Sessão de abertura, João Marques de Almeida, director do Instituto da Defesa Nacional. Painel 1, intervenções de António Vitorino e Gabriel Calderon de Cerqueira Rocha; moderadora Teresa Leal Coelho. Painel 2, intervenções de António Luciano Fontes Ramos, João Manuel Mariz Fernandes; moderador, João Vieira Borges. A sessão de encerramento esteve a cargo de Manuel Lobo Antunes, Secretário de Estado da Defesa Nacional e dos Assuntos do Mar.N/

    Enhanced Fatty Acid Oxidation and FATP4 Protein Expression after Endurance Exercise Training in Human Skeletal Muscle

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    FATP1 and FATP4 appear to be important for the cellular uptake and handling of long chain fatty acids (LCFA). These findings were obtained from loss- or gain of function models. However, reports on FATP1 and FATP4 in human skeletal muscle are limited. Aerobic training enhances lipid oxidation; however, it is not known whether this involves up-regulation of FATP1 and FATP4 protein. Therefore, the aim of this project was to investigate FATP1 and FATP4 protein expression in the vastus lateralis muscle from healthy human individuals and to what extent FATP1 and FATP4 protein expression were affected by an increased fuel demand induced by exercise training. Eight young healthy males were recruited to the study. All subjects were non smokers and did not participate in regular physical activity (<1 time per week for the past 6 months, VO2peak 3.4±0.1 l O2 min−1). Subjects underwent an 8 week supervised aerobic training program. Training induced an increase in VO2peak from 3.4±0.1 to 3.9±0.1 l min−1 and citrate synthase activity was increased from 53.7±2.5 to 80.8±3.7 µmol g−1 min−1. The protein content of FATP4 was increased by 33%, whereas FATP1 protein content was reduced by 20%. Interestingly, at the end of the training intervention a significant association (r2 = 0.74) between the observed increase in skeletal muscle FATP4 protein expression and lipid oxidation during a 120 min endurance exercise test was observed. In conclusion, based on the present findings it is suggested that FATP1 and FATP4 proteins perform different functional roles in handling LCFA in skeletal muscle with FATP4 apparently more important as a lipid transport protein directing lipids for lipid oxidation

    CD133 expression in chemo-resistant Ewing sarcoma cells

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    <p>Abstract</p> <p>Background</p> <p>Some human cancers demonstrate cellular hierarchies in which tumor-initiating cancer stem cells generate progeny cells with reduced tumorigenic potential. This cancer stem cell population is proposed to be a source of therapy-resistant and recurrent disease. Ewing sarcoma family tumors (ESFT) are highly aggressive cancers in which drug-resistant, relapsed disease remains a significant clinical problem. Recently, the cell surface protein CD133 was identified as a putative marker of tumor-initiating cells in ESFT. We evaluated ESFT tumors and cell lines to determine if high levels of CD133 are associated with drug resistance.</p> <p>Methods</p> <p>Expression of the CD133-encoding <it>PROM1 </it>gene was determined by RT-PCR in ESFT tumors and cell lines. CD133 protein expression was assessed by western blot, FACS and/or immunostaining. Cell lines were FACS-sorted into CD133+ and CD133- fractions and proliferation, colony formation in soft agar, and <it>in vivo </it>tumorigenicity compared. Chemosensitivity was measured using MTS (3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxy-methoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium) assays.</p> <p>Results</p> <p><it>PROM1 </it>expression was either absent or extremely low in most tumors. However, <it>PROM1 </it>was highly over-expressed in 4 of 48 cases. Two of the 4 patients with <it>PROM1 </it>over-expressing tumors rapidly succumbed to primary drug-resistant disease and two are long-term, event-free survivors. The expression of <it>PROM1 </it>in ESFT cell lines was similarly heterogeneous. The frequency of CD133+ cells ranged from 2-99% and, with one exception, no differences in the chemoresistance or tumorigenicity of CD133+ and CD133- cell fractions were detected. Importantly, however, the STA-ET-8.2 cell line was found to retain a cellular hierarchy in which relatively chemo-resistant, tumorigenic CD133+ cells gave rise to relatively chemo-sensitive, less tumorigenic, CD133- progeny.</p> <p>Conclusions</p> <p>Up to 10% of ESFT express high levels of <it>PROM1</it>. In some tumors and cell lines the CD133+ fraction is relatively more drug-resistant, while in others there is no apparent difference between CD133+ and CD133- cells. These studies reveal heterogeneity in <it>PROM1</it>/CD133 expression in ESFT tumors and cell lines and confirm that high levels of <it>PROM1 </it>expression are, in at least some cases, associated with chemo-resistant disease. Further studies are required to elucidate the contribution of <it>PROM1/</it>CD133 expressing cells to therapeutic resistance in a large, prospective cohort of primary ESFT.</p
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