258 research outputs found

    Compiling for coarse-grain reconfigurable architectures

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    Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1997.Includes bibliographical references (p. 221-224).by M. Morris E. Matsa.M.Eng

    5-hydroxymethyl-cytosine enrichment of non-committed cells is not a universal feature of vertebrate development

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    5-hydroxymethyl-cytosine (5-hmC) is a cytosine modification that is relatively abundant in mammalian pre-implantation embryos and embryonic stem cells (ESC) derived from mammalian blastocysts. Recent observations imply that both 5-hmC and Tet1/2/3 proteins, catalyzing the conversion of 5-methyl-cytosine to 5-hmC, may play an important role in self renewal and differentiation of ESCs. Here we assessed the distribution of 5-hmC in zebrafish and chick embryos and found that, unlike in mammals, 5-hmC is immunochemically undetectable in these systems before the onset of organogenesis. In addition, Tet1/2/3 transcripts are either low or undetectable at corresponding stages of zebrafish development. However, 5-hmC is enriched in later zebrafish and chick embryos and exhibits tissue-specific distribution in adult zebrafish. Our findings show that 5-hmC enrichment of non-committed cells is not a universal feature of vertebrate development and give insights both into evolution of embryonic pluripotency and the potential role of 5-hmC in its regulation. © 2012 Landes Bioscience

    A comprehensive TALEN-based knockout library for generating human induced pluripotent stem cell-based models for cardiovascular diseases

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    Rationale: Targeted genetic engineering using programmable nucleases such as transcription activator-like effector nucleases (TALENs) is a valuable tool for precise, site-specific genetic modification in the human genome. Objective: The emergence of novel technologies such as human induced pluripotent stem cells (iPSCs) and nuclease-mediated genome editing represent a unique opportunity for studying cardiovascular diseases in vitro. Methods and Results: By incorporating extensive literature and database searches, we designed a collection of TALEN constructs to knockout (KO) eighty-eight human genes that are associated with cardiomyopathies and congenital heart diseases. The TALEN pairs were designed to induce double-strand DNA break near the starting codon of each gene that either disrupted the start codon or introduced a frameshift mutation in the early coding region, ensuring faithful gene KO. We observed that all the constructs were active and disrupted the target locus at high frequencies. To illustrate the general utility of the TALEN-mediated KO technique, six individual genes (TNNT2, LMNA/C, TBX5, MYH7, ANKRD1, and NKX2.5) were knocked out with high efficiency and specificity in human iPSCs. By selectively targeting a dilated cardiomyopathy (DCM)-causing mutation (TNNT2 p.R173W) in patient-specific iPSC-derived cardiac myocytes (iPSC-CMs), we demonstrated that the KO strategy ameliorates the DCM phenotype in vitro. In addition, we modeled the Holt-Oram syndrome (HOS) in iPSC-CMs in vitro and uncovered novel pathways regulated by TBX5 in human cardiac myocyte development. Conclusions: Collectively, our study illustrates the powerful combination of iPSCs and genome editing technology for understanding the biological function of genes and the pathological significance of genetic variants in human cardiovascular diseases. The methods, strategies, constructs and iPSC lines developed in this study provide a validated, readily available resource for cardiovascular research

    Atomic Force Mechanobiology of Pluripotent Stem Cell-Derived Cardiomyocytes

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    We describe a method using atomic force microscopy (AFM) to quantify the mechanobiological properties of pluripotent, stem cell-derived cardiomyocytes, including contraction force, rate, duration, and cellular elasticity. We measured beats from cardiomyocytes derived from induced pluripotent stem cells of healthy subjects and those with dilated cardiomyopathy, and from embryonic stem cell lines. We found that our AFM method could quantitate beat forces of single cells and clusters of cardiomyocytes. We demonstrate the dose-responsive, inotropic effect of norepinephrine and beta-adrenergic blockade of metoprolol. Cardiomyocytes derived from subjects with dilated cardiomyopathy showed decreased force and decreased cellular elasticity compared to controls. This AFM-based method can serve as a screening tool for the development of cardiac-active pharmacological agents, or as a platform for studying cardiomyocyte biology

    Advanced maturation of human cardiac tissue grown from pluripotent stem cells

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    Cardiac tissues generated from human induced pluripotent stem cells (iPSCs) can serve as platforms for patient-specific studies of physiology and disease1-6. However, the predictive power of these models is presently limited by the immature state of the cells1, 2, 5, 6. Here we show that this fundamental limitation can be overcome if cardiac tissues are formed from early-stage iPSC-derived cardiomyocytes soon after the initiation of spontaneous contractions and are subjected to physical conditioning with increasing intensity over time. After only four weeks of culture, for all iPSC lines studied, such tissues displayed adult-like gene expression profiles, remarkably organized ultrastructure, physiological sarcomere length (2.2 µm) and density of mitochondria (30%), the presence of transverse tubules, oxidative metabolism, a positive force-frequency relationship and functional calcium handling. Electromechanical properties developed more slowly and did not achieve the stage of maturity seen in adult human myocardium. Tissue maturity was necessary for achieving physiological responses to isoproterenol and recapitulating pathological hypertrophy, supporting the utility of this tissue model for studies of cardiac development and disease.The authors acknowledge funding support from the National Institutes of Health of the USA (NIBIB and NCATS grant EB17103 (G.V.-N.); NIBIB, NCATS, NIAMS, NIDCR and NIEHS grant EB025765 (G.V.-N.); NHLBI grants HL076485 (G.V.-N.) and HL138486 (M.Y.); Columbia University MD/PhD program (S.P.M., T.C.); University of Minho MD/PhD program (D.T.); Japan Society for the Promotion of Science fellowship (K.M.); and Columbia University Stem Cell Initiative (D.S., L.S., M.Y.). We thank S. Duncan and B. Conklin for providing human iPSCs, M.B. Bouchard for assistance with image and video analysis, and L. Cohen-Gould for transmission electron microscopy services.info:eu-repo/semantics/publishedVersio

    HEALTHCARE PROCESS OF THE PATIENT WITH ACUTE PANCREATITIS

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    Akutni pankreatitis je nagla upala gušterače koja se može javiti u blagom ili teškom obliku. Ova nagla upala se u gotovo 80% prijema u bolnicu pripisuje postojanju žučnih kamenaca ili konzumaciji alkohola. Žučni kamenci kao uzrok budu 1,5 puta češći kod žena, dok se alkohol kao uzrok u muškaraca pojavljuje šest puta više nego kod žena. Žučni kamenci najčešće začepe otvor pankreatičnog voda ili se na neko vrijeme zaustave u Oddijevu sfinkteru uzrokujući time upalu dok svakodnevna konzumacija alkohola također može dovesti do začepljenja malih vodova. Jaki bolovi se javljaju najčešće naglo nakon konzumacije prekomjerne količine obroka ili alkohola u gornjem srednjem dijelu abdomena. Osim što je bol nagla, pacijenti je opisuju kao probadajuću bol koja se širi u leđa. Može se javiti mučnina kao i nagon na povraćanje, u većini slučajeva popratnu uz temperaturu. Bolesnik se javlja u hitni trakt radi jakih bolova koji se ne smanjuju te se podvrgava daljnjoj dijagnostici. Laboratorijskim pretragama ne može se potvrditi dijagnoza akutnog pankreatitisa ali povišenom razinom enzima gušterače tu dijagnozu možemo potkrijepiti. Daljnjim radiološkim pretragama (rendgen abdomena, kompjutorizirana tomografija) dokazuje se mogućnost postojanja žučnih kamenaca kao i promjene u veličini i strukturi gušterače. Sa utvrđenom dijagnozom akutnog pankreatitisa, osoba se zaprima na odjel gdje se prekida daljnji unos hrane i pića kako bi se smanjila daljnja proizvodnja enzima u gušterači. Svu potrebnu tekućinu i ostale hranjive tvari nadoknađuju se intravenskim putem. U cijelom procesu liječenja ključna je i medicinska sestra koja najprije može uočiti eventualne promjene koje se mogu javiti kod pacijenta, kao što su primjerice smanjeno mokrenje, otežano disanje te stagniranje ili pogoršavanje intenziteta boli unatoč primijenjenoj analgetskoj terapiji.Acute pancreatitis is a sudden pancreatic inflammation occurring in mild or severe form. This sudden inflammation in almost 80% of admission to the hospital is attributed to the existence of gallstones or drinking alcohol. The gallstones as a cause of Acute pancreatitis are 1.5 times more common in women, while alcohol as a cause is present men appears six times more than in women. Gallstones usually close the pancreatic opening or stop for a while in Oddies sphincter causing it to inflate ,while daily alcohol consumption also leads to clogging of small lines. Strong pain usually are occurring suddnely after eating excessive meals or presence of alcohol in the upper mid-section of the abdomen. Apart pain is acute, patients are describeing as a stabbing kind of pain that is spreading in their back. There can be nausea and vomiting, in most cases accompanied by temperature. The patient is coming to an emergency with severe pain that does not diminish and undergoes further diagnosis. Laboratory examinations can not confirm the diagnosis of acute pancreatitis but elevated pancreatic enzyme levels can be supported by this diagnosis. Further radiological examinations (X-ray abdomena, computerized tomography) are proveing the possibility of gallstones as well as changes in the size and structure of the pancreas. With established diagnosis of acute pancreatitis, a person is hospitalized in intensice care where further food and drink intake is discontinued in order to reduce further enzyme production in the pancreas. All the necessary fluid and other nutrients are compensated by the intravenous. Throughout the process of treatment, role of nurse is also crucial to notice possible changes that may occur in the patient, such as decreased urination, difficulty breathing and stagnation or aggravation of pain intensity despite analgesic therapy
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