469 research outputs found
Real-time PCR based on SYBR-Green I fluorescence: An alternative to the TaqMan assay for a relative quantification of gene rearrangements, gene amplifications and micro gene deletions
BACKGROUND:
Real-time PCR is increasingly being adopted for RNA quantification and genetic analysis. At present the most popular real-time PCR assay is based on the hybridisation of a dual-labelled probe to the PCR product, and the development of a signal by loss of fluorescence quenching as PCR degrades the probe. Though this so-called 'TaqMan' approach has proved easy to optimise in practice, the dual-labelled probes are relatively expensive.
RESULTS:
We have designed a new assay based on SYBR-Green I binding that is quick, reliable, easily optimised and compares well with the published assay. Here we demonstrate its general applicability by measuring copy number in three different genetic contexts; the quantification of a gene rearrangement (T-cell receptor excision circles (TREC) in peripheral blood mononuclear cells); the detection and quantification of GLI, MYC-C and MYC-N gene amplification in cell lines and cancer biopsies; and detection of deletions in the OPA1 gene in dominant optic atrophy.
CONCLUSION:
Our assay has important clinical applications, providing accurate diagnostic results in less time, from less biopsy material and at less cost than assays currently employed such as FISH or Southern blotting
Tunneling of massive and charged particles from noncommutative Reissner-Nordstr\"{o}m black hole
Massive charged and uncharged particles tunneling from commutative
Reissner-Nordstrom black hole horizon has been studied with details in
literature. Here, by adopting the coherent state picture of spacetime
noncommutativity, we study tunneling of massive and charged particles from a
noncommutative inspired Reissner-Nordstrom black hole horizon. We show that
Hawking radiation in this case is not purely thermal and there are correlations
between emitted modes. These correlations may provide a solution to the
information loss problem. We also study thermodynamics of noncommutative
horizon in this setup.Comment: 10 pages, 2 figure
Background field quantization and non-commutative Maxwell theory
We quantize non-commutative Maxwell theory canonically in the background
field gauge for weak and slowly varying background fields. We determine the
complete basis for expansion under such an approximation. As an application, we
derive the Wigner function which determines the leading order high temperature
behavior of the perturbative amplitudes of non-commutative Maxwell theory. To
leading order, we also give a closed form expression for the distribution
function for the non-commutative gauge theory at high temperature.Comment: 9 pages, title slightly modified, to appear in Physics Letters
Interleukin-7 deficiency in rheumatoid arthritis: consequences for therapy-induced lymphopenia
We previously demonstrated prolonged, profound CD4+ T-lymphopenia in rheumatoid arthritis (RA) patients following lymphocyte-depleting therapy. Poor reconstitution could result either from reduced de novo T-cell production through the thymus or from poor peripheral expansion of residual T-cells. Interleukin-7 (IL-7) is known to stimulate the thymus to produce new T-cells and to allow circulating mature T-cells to expand, thereby playing a critical role in T-cell homeostasis. In the present study we demonstrated reduced levels of circulating IL-7 in a cross-section of RA patients. IL-7 production by bone marrow stromal cell cultures was also compromised in RA. To investigate whether such an IL-7 deficiency could account for the prolonged lymphopenia observed in RA following therapeutic lymphodepletion, we compared RA patients and patients with solid cancers treated with high-dose chemotherapy and autologous progenitor cell rescue. Chemotherapy rendered all patients similarly lymphopenic, but this was sustained in RA patients at 12 months, as compared with the reconstitution that occurred in cancer patients by 3â4 months. Both cohorts produced naĂŻve T-cells containing T-cell receptor excision circles. The main distinguishing feature between the groups was a failure to expand peripheral T-cells in RA, particularly memory cells during the first 3 months after treatment. Most importantly, there was no increase in serum IL-7 levels in RA, as compared with a fourfold rise in non-RA control individuals at the time of lymphopenia. Our data therefore suggest that RA patients are relatively IL-7 deficient and that this deficiency is likely to be an important contributing factor to poor early T-cell reconstitution in RA following therapeutic lymphodepletion. Furthermore, in RA patients with stable, well controlled disease, IL-7 levels were positively correlated with the T-cell receptor excision circle content of CD4+ T-cells, demonstrating a direct effect of IL-7 on thymic activity in this cohort
GATA-2 and GATA-3 regulate trophoblast-specific gene expression in vivo.
We previously demonstrated that the zinc finger transcription factors GATA-2 and GATA-3 are expressed in trophoblast giant cells and that they regulate transcription from the mouse placental lactogen I gene promoter in a transfected trophoblast cell line. We present evidence here that both of these factors regulate transcription of the placental lactogen I gene, as well as the related proliferin gene, in trophoblast giant cells in vivo. Placentas lacking GATA-3 accumulate placental lactogen I and proliferi
Non-Perturbative String Equations for Type 0A
Well-defined non-perturbative formulations of the physics of string theories,
sometimes with D-branes present, were identified over a decade ago, from a
careful study of double scaled matrix models. Following recent work which
recasts some of those old results in the context of type 0 string theory, a
study is made of a much larger family of models, which are proposed as type 0A
models of the entire superconformal minimal series coupled to gravity. This
gives many further examples of important physical phenomena, including
non-perturbative descriptions of transitions between D-branes and fluxes,
tachyon condensation, and holography. In particular, features of a large family
of non-perturbatively stable string equations are studied, and results are
extracted which pertain to type 0A string theory, with D-branes and fluxes, in
this large class of backgrounds. For the entire construction to work, large
parts of the spectrum of the supergravitationally dressed superconformal
minimal models and that of the gravitationally dressed bosonic conformal
minimal models must coincide, and it is shown how this happens. The example of
the super-dressed tricritical Ising model is studied in some detail.Comment: 29 pages LaTe
Two-Dimensional Unoriented Strings And Matrix Models
We investigate unoriented strings and superstrings in two dimensions and
their dual matrix quantum mechanics. Most of the models we study have a tachyon
tadpole coming from the RP^2 worldsheet which needs to be cancelled by a
renormalization of the worldsheet theory. We find evidence that the dual matrix
models describe the renormalized theory. The singlet sector of the matrix
models is integrable and can be formulated in terms of fermions moving in an
external potential and interacting via the Calogero-Moser potential. We show
that in the double-scaling limit the latter system exhibits particle-hole
duality and interpret it in terms of the dual string theory. We also show that
oriented string theories in two dimensions can be continuously deformed into
unoriented ones by turning on non-local interactions on the worldsheet. We find
two unoriented superstring models for which only oriented worldsheets
contribute to the S-matrix. A simple explanation for this is found in the dual
matrix model.Comment: 36 pages, harvmac, 2 eps figure
Scattered Results in 2D String Theory
The nonperturbative tachyon scattering amplitude in 2D type 0A
string theory is computed. The probability that particles are produced is a
monotonically decreasing function of whenever is large enough that
statistical methods apply. The results are compared with expectations from
black hole thermodynamics.Comment: 22 pages, 5 figures, harvmac. v2: minor comments added, typos
correcte
D-branes at multicritical points
The moduli space of c=1 conformal field theories in two dimensions has a
multicritical point, where a circle theory is equivalent to an orbifold theory.
We analyse all the conformal branes in both descriptions of this theory, and
find convincing evidence that the full brane spectrum coincides. This shows
that the equivalence of the two descriptions at this multicritical point
extends to the boundary sector. We also perform the analogous analysis for one
of the multicritical points of the N=1 superconformal field theories at c=3/2.
Again the brane spectra are identical for both descriptions, however the
identification is more subtle.Comment: 32 pages, 2 figure
Comments on 2D Type IIA String and Matrix Model
We consider a type IIA-like string theory with RR-flux in two dimension and
propose its matrix model dual. This string theory describes a Majorana fermion
in the two dimensional spacetime. We also discuss its scattering amplitudes
both in the world-sheet theory and in the matrix model.Comment: 21 pages, Harvmac, to appear in JHEP, relation to 2d superstring
constructed by D. Kutasov hep-th/9110041 is clarifie
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