409 research outputs found
Two stochastic models for simulation of correlated random processes
Mathematical models for simulation of correlated stochastic processes with stationary Gaussian propertie
Palladium-Catalyzed Amination of Unprotected Five-Membered Heterocyclic Bromides
An efficient method for the palladium-catalyzed amination of unprotected bromoimidazoles and bromopyrazoles is presented. The transformation is facilitated by the use of our newly developed Pd precatalyst based on the bulky biarylphosphine ligand tBuBrettPhos (L4). The mild reaction conditions employed allow for the preparation of a broad scope of aminoimidazoles and aminopyrazoles in moderate to excellent yields.National Institutes of Health (U.S.) (Award GM58160)Astellas USA Foundation (Fellowship)Japan Society for the Promotion of Science (Young Scientist Research Fellowship
Classification of three generation models by orbifolding magnetized
We study orbifolding by the permutaion of with magnetic fluxes and its twisted orbifolds. We classify the
possible three generation models which lead to non-vanishing Yukawa couplings
on the magnetized and orbifolds including the
permutation and twist. We
also study the modular symmetry on such orbifold models. As an illustrating
model, we examine the realization of quark masses and mixing angles.Comment: 31 page
Spontaneous Extraskeletal Osteosarcoma in the Stomach of an Aged F344 Rat
Extraskeletal osteosarcoma is a very rare tumor in humans and animals including
rats. This paper describes a case of extraskeletal osteosarcoma observed in the
glandular stomach of an aged female Fischer 344 rat. Grossly, a whitish solid
mass was observed at the greater curvature of the glandular stomach.
Histologically, the tumor consisted of both atypical polygonal and pleomorphic
spindle-shaped cells, with pleomorphic nuclei, and it contained variable amounts
of osteoids and small clumps of mature bone tissue. In addition, mitotic figures
were frequently observed. Neither invasion of the muscle layer or vessels in the
stomach nor metastasis to distant organs was detected. There were no skeletal
tumors in the body. Immunohistochemically, the tumor cells were positive for
osteocalcin, osteonectin, vimentin and S-100 protein. Judging from these
results, the present tumor was diagnosed as extraskeletal osteosarcoma. This is
the first report of spontaneous extraskeletal osteosarcoma arising from the
stomach in a rat
Human artificial chromosome with a conditional centromere for gene delivery and gene expression.
Human artificial chromosomes (HACs), which carry a fully functional centromere and are maintained as a single-copy episome, are not associated with random mutagenesis and offer greater control over expression of ectopic genes on the HAC. Recently, we generated a HAC with a conditional centromere, which includes the tetracycline operator (tet-O) sequence embedded in the alphoid DNA array. This conditional centromere can be inactivated, loss of the alphoid(tet-O) (tet-O HAC) by expression of tet-repressor fusion proteins. In this report, we describe adaptation of the tet-O HAC vector for gene delivery and gene expression in human cells. A loxP cassette was inserted into the tet-O HAC by homologous recombination in chicken DT40 cells following a microcell-mediated chromosome transfer (MMCT). The tet-O HAC with the loxP cassette was then transferred into Chinese hamster ovary cells, and EGFP transgene was efficiently and accurately incorporated into the tet-O HAC vector. The EGFP transgene was stably expressed in human cells after transfer via MMCT. Because the transgenes inserted on the tet-O HAC can be eliminated from cells by HAC loss due to centromere inactivation, this HAC vector system provides important novel features and has potential applications for gene expression studies and gene therapy
Complete Genetic Correction of iPS Cells From Duchenne Muscular Dystrophy
Human artificial chromosome (HAC) has several advantages as a gene therapy vector, including stable episomal maintenance that avoids insertional mutations and the ability to carry large gene inserts including the regulatory elements. Induced pluripotent stem (iPS) cells have great potential for gene therapy, as such cells can be generated from the individual's own tissues, and when reintroduced can contribute to the specialized function of any tissue. As a proof of concept, we show herein the complete correction of a genetic deficiency in iPS cells derived from Duchenne muscular dystrophy (DMD) model (mdx) mice and a human DMD patient using a HAC with a complete genomic dystrophin sequence (DYS-HAC). Deletion or mutation of dystrophin in iPS cells was corrected by transferring the DYS-HAC via microcell-mediated chromosome transfer (MMCT). DMD patient- and mdx-specific iPS cells with the DYS-HAC gave rise to differentiation of three germ layers in the teratoma, and human dystrophin expression was detected in muscle-like tissues. Furthermore, chimeric mice from mdx-iPS (DYS-HAC) cells were produced and DYS-HAC was detected in all tissues examined, with tissue-specific expression of dystrophin. Therefore, the combination of patient-specific iPS cells and HAC-containing defective genes represents a powerful tool for gene and cell therapies
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