2,029 research outputs found
miR-CATCH identifies biologically active miRNA regulators of the pro-survival gene XIAP, in Chinese hamster ovary cells
Genetic engineering of mammalian cells, in particular Chinese hamster ovary (CHO) cells, is of critical interest to the biopharmaceutical industry as a means to further boost the yields of therapeutic proteins. Complimentary to already in place advanced bioprocesses, stable overexpression of the pro-survival X-linked inhibitor of apoptosis (XIAP) is one example of the successful manipulation of CHO cell genetics resulting in prolonged culture survival, ultimately increasing recombinant protein productivity. However, saturation or burdening of the cells translational machinery can occur in instances of forced expression of a trans-gene thereby achieving the anticipated cellular phenotype without the associated improvement in productivity. Ribosomal footprint sequencing has demonstrated that ~15% of an IgG-producing CHO cell translatome is occupied by the Neomycin selection marker. microRNAs (miRNAs) have the ability to fine tune endogenous gene expression thereby achieving elevated gene levels without the excess that could negatively impact global gene expression. Additionally, not only does a single miRNA have the capacity to regulate multiple mRNA transcripts simultaneously but individual mRNAs can be regulated by a multitude of miRNAs at the post-transcriptional level. This can facilitate the maximal translation of an endogenous gene without surpassing the superphysiological threshold associated with diminished productivity. The promiscuous nature of miRNA represented by the variety of binding patterns associated with mRNA targeting limits the predictability of high confidence miRNA regulators of attractive engineering candidates. This results in a lengthy list of falsely predicted in-silico miRNA regulators for a single gene. We explored the identification of direct miRNA regulators of the pro-survival endogenous XIAP gene in CHO-K1 cells by using a miR-CATCH1 protocol. A biotin-tagged antisense DNA oligonucleotide was designed for an exposed predicted secondary structure loop of endogenous CHO XIAP. This mRNA anchor resulted in the pulldown of XIAP and all associated RNA/protein complexes thereby enriching for all bound miRNAs. Two miRNAs were chosen out of the 14 miRNAs identified for further validation, miR-124-3p and miR-19b-3p. Transient transfection of mimics for both resulted in the diminished translation of endogenous CHO XIAP protein whereas their inhibition increased XIAP protein levels (Fig. 1).
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Study of the Hindrance Effect in Sub-barrier Fusion Reactions
We have measured the fusion cross sections of the 12C(13C, p)24Na reaction
through off-line measurement of the beta-decay of 24Na using the beta-gamma
coincidence method. Our new measurements in the energy range of Ec.m. = 2.6-3.0
MeV do not show an obvious S-factor maximum but a plateau. Comparison between
this work and various models is presented.Comment: 3 pages, 3 figures, Talk at the "10th International Conference on
Nucleus-Nucleus Collisions", Beijing, 16-21 August 200
Information sharing and credit : firm-level evidence from transition countries
We investigate whether information sharing among banks has affected credit market performance in the transition countries of Eastern Europe and the former Soviet Union, using a large sample of firm-level data. Our estimates show that information sharing is associated with improved availability and lower cost of credit to firms. This correlation is stronger for opaque firms than transparent ones and stronger in countries with weak legal environments than in those with strong legal environments. In cross-sectional estimates, we control for variation in country-level aggregate variables that may affect credit, by examining the differential impact of information sharing across firm types. In panel estimates, we also control for the presence of unobserved heterogeneity at the firm level, as well as for changes in macroeconomic variables and the legal environment
The class of the locus of intermediate Jacobians of cubic threefolds
We study the locus of intermediate Jacobians of cubic threefolds within the
moduli space of complex principally polarized abelian fivefolds, and its
generalization to arbitrary genus - the locus of abelian varieties with a
singular odd two-torsion point on the theta divisor. Assuming that this locus
has expected codimension (which we show to be true for genus up to 5), we
compute the class of this locus, and of is closure in the perfect cone toroidal
compactification, in the Chow, homology, and the tautological ring.
We work out the cases of genus up to 5 in detail, obtaining explicit
expressions for the classes of the closures of the locus of products of an
elliptic curve and a hyperelliptic genus 3 curve, in moduli of principally
polarized abelian fourfolds, and of the locus of intermediate Jacobians in
genus 5. In the course of our computation we also deal with various
intersections of boundary divisors of a level toroidal compactification, which
is of independent interest in understanding the cohomology and Chow rings of
the moduli spaces.Comment: v2: new section 9 on the geometry of the boundary of the locus of
intermediate Jacobians of cubic threefolds. Final version to appear in
Invent. Mat
Parasitic Cape honeybee workers, Apis mellifera capensis, evade policing
Relocation of the Cape honeybee, Apis mellifera capensis, by bee-keepers from southern to northern South Africa in 1990 has caused widespread death of managed African honeybee, A. m. scutellata, colonies. Apis mellifera capensis worker bees are able to lay diploid, female eggs without mating by means of automictic thelytoky (meiosis followed by fusion of two meiotic products to restore egg diploidy), whereas workers of other honeybee subspecies are able to lay only haploid, male eggs. The A. m. capensis workers, which are parasitizing and killing A. m. scutellata colonies in northern South Africa, are the asexual offspring of a single, original worker in which the small amount of genetic variation observed is due to crossing over during meiosis (P. Kryger, personal communication). Here we elucidate two principal mechanisms underlying this parasitism. Parasitic A. m. capensis workers activate their ovaries in host colonies that have a queen present (queenright colonies), and they lay eggs that evade being killed by other workers (worker policing)—the normal fate of worker-laid eggs in colonies with a queen. This unique parasitism by workers is an instance in which a society is unable to control the selfish actions of its members
Urinary Kininogen-1 and Retinol binding protein-4 respond to Acute Kidney Injury: Predictors of patient prognosis?
Implementation of therapy for acute kidney injury (AKI) depends on successful prediction of individual patient prognosis. Clinical markers as serum creatinine (sCr) have limitations in sensitivity and early response. The aim of the study was to identify novel molecules in urine which show altered levels in response to AKI and investigate their value as predictors of recovery. Changes in the urinary proteome were here investigated in a cohort of 88 subjects (55 AKI patients and 33 healthy donors) grouped in discovery and validation independent cohorts. Patients'urine was collected at three time points: within the first 48 h after diagnosis(T1), at 7 days of follow-up(T2) and at discharge of Nephrology(T3). Differential gel electrophoresis was performed and data were confirmed by Western blot (WB), liquid chromatography/mass spectrometry (LC-MS/MS) and enzyme-linked immunosorbent assay (ELISA). Retinol binding protein 4 (RBP4) and kininogen-1 (KNG1) were found significantly altered following AKI. RBP4 increased at T1, and progressively decreased towards normalization. Maintained decrease was observed for KNG1 from T1. Individual patient response along time revealed RBP4 responds to recovery earlier than sCr. In conclusion, KNG1 and RBP4 respond to AKI. By monitoring RBP4, patient's recovery can be anticipated pointing to a role of RBP4 in prognosis evaluation.Funding: from Instituto de Salud Carlos III: FIS PI11/01401, PI13/01873, FIS IF08/3667-1,
CP09/00229, PI13/00047, PI10/00624, ISCIII-RETIC REDinREN RD012/0021. FEDER funds, Comunidad de Madrid/CIFRA S2010/BMD-2378, Programa IntensificaciĂłn Actividad Investigadora (ISCIII/Agencia LaĂn-Entralgo/CM) to AO, IDCSalud (3371/002) and FundaciĂłn Conchita Rábago de JimĂ©nez DĂaz, Proteomic Facility from Universidad Complutense de Madrid-FundaciĂłn Parque CientĂfico de Madrid (UCM-FPCM), Spain, a member of ProteoRed-ISCIII Network
member of ProteoRed-
ISCIII Networ
A proposed framework for consensus-based lung tumour volume auto-segmentation in 4D computed tomography imaging.
This work aims to propose and validate a framework for tumour volume auto-segmentation based on ground-truth estimates derived from multi-physician input contours to expedite 4D-CT based lung tumour volume delineation. 4D-CT datasets of ten non-small cell lung cancer (NSCLC) patients were manually segmented by 6 physicians. Multi-expert ground truth (GT) estimates were constructed using the STAPLE algorithm for the gross tumour volume (GTV) on all respiratory phases. Next, using a deformable model-based method, multi-expert GT on each individual phase of the 4D-CT dataset was propagated to all other phases providing auto-segmented GTVs and motion encompassing internal gross target volumes (IGTVs) based on GT estimates (STAPLE) from each respiratory phase of the 4D-CT dataset. Accuracy assessment of auto-segmentation employed graph cuts for 3D-shape reconstruction and point-set registration-based analysis yielding volumetric and distance-based measures. STAPLE-based auto-segmented GTV accuracy ranged from (81.51  ±  1.92) to (97.27  ±  0.28)% volumetric overlap of the estimated ground truth. IGTV auto-segmentation showed significantly improved accuracies with reduced variance for all patients ranging from 90.87 to 98.57% volumetric overlap of the ground truth volume. Additional metrics supported these observations with statistical significance. Accuracy of auto-segmentation was shown to be largely independent of selection of the initial propagation phase. IGTV construction based on auto-segmented GTVs within the 4D-CT dataset provided accurate and reliable target volumes compared to manual segmentation-based GT estimates. While inter-/intra-observer effects were largely mitigated, the proposed segmentation workflow is more complex than that of current clinical practice and requires further development
Stigma narratives: LGBT transitions and identities in Malta
This article is available open access through the publisher’s website at the link below. Copyright @ 2011 A B Academic Publishers.This article considers narratives of transition experiences of a group of Lesbian, Gay, Bisexual and Transgender (LGBT) young people in Malta. The article draws on Goffman's concept of stigma and uses this to explore transitions in a society that retains some traditional characteristics, particularly the code of honour and shame, although mediated by aspects of modernity. Interviews were undertaken with 15 young people with the goal of producing narratives. The article analyses the experience of stigma, its effects and how young people manage its consequences. It concludes by drawing attention to the pervasive nature of stigma and the importance of structure, agency and reflexivity in youth transitions. In particular stigma remains an important feature of societies in which hetero-normative sexuality remains dominant
Subcutaneous rupture of the Achilles tendon and ipsilateral fracture of the medial malleolus
BACKGROUND: Although ankle fractures and an Achilles tendon rupture are relatively frequent in isolation, their association in the same injury is uncommon. CASE PRESENTATION: A 38 year old male tree surgeon fell six meters from a tree, sustaining a subcutaneous rupture of the Achilles tendon and an ipsilateral closed fracture of the medial malleolus. The injuries were diagnosed following clinical examination and imaging. CONCLUSION: This injury combination is infrequent, and management of the Achilles tendon rupture should take into account the necessity not to secondarily displace the fracture of the medial malleollus
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