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Biomedical subjects

Y Shin

Publications and source records attributed to Y Shin.

At least 37 records · Page 2Linked to original sources
PubMed2003

Adult polyglucosan body disease: a postmortem correlation study.

Autopsy of a 50-year-old woman with adult polyglucosan body disease and missense mutations (Arg515His, Arg524Gln) in the glycogen branching enzyme gene (GBE) revealed accumulation of polyglucosan bodies in the heart, brain, and nerve. GBE activity was decreased in the morphologically affected tissues but was normal in unaffected tissues. GBE mRNA transcripts were similar in all tissues and in controls, which confirms the lack of tissue-specific GBE isoforms.

1,4-alpha-Glucan Branching Enzyme↗
PubMed2003

Coreless vortex formation in a spinor Bose-Einstein condensate.

Coreless vortices were phase imprinted in a spinor Bose-Einstein condensate. The three-component order parameter of F=1 sodium condensates held in a Ioffe-Pritchard magnetic trap was manipulated by adiabatically reducing the magnetic bias field along the trap axis to zero. This distributed the condensate population across its three spin states and created a spin texture. Each spin state acquired a different phase winding which caused the spin components to separate radially.

Journal Article↗
PubMed2003

Hemorrhagic stroke associated with the Iowa amyloid precursor protein mutation.

The authors searched for mutations in the beta-amyloid precursor protein in a Spanish family with a hereditary syndrome of hemorrhagic stroke, dementia, leukoencephalopathy, and occipital calcifications. DNA from two affected members demonstrated the Iowa amyloid precursor protein mutation previously identified as a cause of severe amyloid angiopathy without hemorrhagic stroke. These data point to other genetic or environmental factors that may determine the occurrence of symptomatic hemorrhage in amyloid angiopathy.

Age of Onset↗
PubMed2003

Bose-Einstein condensates near a microfabricated surface.

Magnetically and optically confined Bose-Einstein condensates were studied near a microfabricated surface. Condensate fragmentation observed in microfabricated magnetic traps was not observed in optical dipole traps at the same location. The measured condensate lifetime was >or=20 s and independent of the atom-surface separation under both magnetic and optical confinement. Radio-frequency spin-flip transitions driven by technical noise were directly observed for optically confined condensates and could limit the condensate lifetime in microfabricated magnetic traps.

Journal Article↗
PubMed2003

Germline mutations of the MEN1 gene in Korean families with multiple endocrine neoplasia type 1 (MEN1) or MEN1-related disorders.

Multiple endocrine neoplasia type 1 (MEN1) is a familial cancer syndrome characterized by the combined occurrence of tumours of the parathyroid glands, pancreatic islet cells and anterior pituitary gland. Mutation analysis of the MEN1 gene has enabled the genetic diagnosis of patients with MEN1. Two MEN1-related disorders - familial isolated hyperparathyroidism (FIHP) and familial pituitary adenoma - are considered to be variants of MEN1, or at least to be incompletely expressed variants. Germline mutations of the MEN1 gene have been reported in some with FIHP, but familial pituitary adenoma usually lacks the MEN1 mutation and has been described as a genetically distinct disorder. In this work, we investigated five Korean families with MEN1, one family with FIHP and one family with familial pituitary adenoma. Polymerase chain reaction (PCR)-based single-strand conformation polymorphism (PCR-SSCP) analysis, denaturing high-performance liquid chromatography (DHPLC) and sequencing were used to detect the MEN1 mutations. Screening of the genetic variations of the MEN1 gene revealed four germline mutations in five typical MEN1 families. All four germline mutations led to truncated proteins or a change in the amino acids of the functional domains. In this study, we identified three novel MEN1 germline mutations (969C >A, 973G >C and 1213C >T) and one previously reported mutation (200-201insAGCCC). The frequency of the MEN1 germline mutation in Korean MEN1 families (four of five; 80%) was similar to those reported previously. In accordance with previous studies, no MEN1 germline mutation was detected in two families with FIHP or familial pituitary adenoma.

DNA Mutational Analysis↗
PubMed2002

Imprinting vortices in a Bose-Einstein condensate using topological phases.

Vortices were imprinted in a Bose-Einstein condensate using topological phases. Sodium condensates held in a Ioffe-Pritchard magnetic trap were transformed from a nonrotating state to one with quantized circulation by adiabatically inverting the magnetic bias field along the trap axis. Using surface wave spectroscopy, the axial angular momentum per particle of the vortex states was found to be consistent with 2 variant Planck's over 2pi or 4 variant Planck's over 2pi, depending on the hyperfine state of the condensate.

Journal Article↗
PubMed2002

Propagation of Bose-Einstein condensates in a magnetic waveguide.

Gaseous Bose-Einstein condensates of 2-3 x 10(6) 23Na atoms were loaded into a microfabricated magnetic trap using optical tweezers. Subsequently, the condensates were released into a magnetic waveguide and propagated 12 mm. Single-mode propagation was observed along homogeneous segments of the waveguide. Inhomogeneities in the guiding potential arose from geometric deformations of the microfabricated wires and caused strong transverse excitations. Such deformations may restrict the waveguide physics that can be explored with propagating condensates. Finer perturbations to the guiding potential fragmented the condensate when it was brought closer to the surface.

Journal Article↗
PubMed2002

A continuous source of Bose-Einstein condensed atoms.

A continuous source of Bose-Einstein condensed sodium atoms was created by periodically replenishing a condensate held in an optical dipole trap with new condensates delivered using optical tweezers. The source contained more than 1 x 10(6) atoms at all times, raising the possibility of realizing a continuous atom laser.

Journal Article↗
PubMed2001

A novel class of highly potent, selective, and non-peptidic inhibitor of Ras farnesyltransferase (FTase).

Design, synthesis and structure-activity relationship of a class of aryl pyrroles as farnesyltransferase inhibitors are described. In vitro and in vivo evaluation of a panel of these inhibitors led to identification of 2 (LB42908) as a highly potent (IC(50)=0.9 nM against H-Ras and 2.4 nM against K-Ras) antitumor agent that is currently undergoing preclinical studies.

Alkyl and Aryl Transferases↗
PubMed2001

Hybrid nanogels for sustainable positive thermosensitive drug release.

A hybrid nanogel has been developed based on interpenetrating networks of thermosensitive poly(N-isopropylacrylamide) gels and tailored nanoporous silica. A sustainable positive thermo-responsive drug release profile is obtained. When the temperature rises, the polymer gel shrinks, squeezing the drug into the porous channels, and at the same time, opening the pores to the outside media. The drug slowly diffuses out of the porous channels. The overall release rate can be adjusted by changing the composition of the nanogel.

Acrylic Resins↗
PubMed2001

Rhodocytin induces platelet aggregation by interacting with glycoprotein Ia/IIa (GPIa/IIa, Integrin alpha 2beta 1). Involvement of GPIa/IIa-associated src and protein tyrosine phosphorylation.

Although glycoprotein Ia/IIa (GPIa/IIa, integrin alpha(2)beta(1)) has established its role as a collagen receptor, it remains unclear whether GPIa/IIa mediates activation signals. In this study, we show that rhodocytin, purified from the Calloselasma rhodostoma venom, induces platelet aggregation, which can be blocked by anti-GPIa monoclonal antibodies. Studies with rhodocytin-coupled beads and liposomes loaded with recombinant GPIa/IIa demonstrated that rhodocytin directly binds to GPIa/IIa independently of divalent cations. In vitro kinase assays and Western blotting of GPIa immunoprecipitates revealed that Src and Lyn constitutively associate with GPIa/IIa and that Src activity increases transiently after rhodocytin stimulation. Src specifically associates with p130 Crk-associated substrate (Cas) in a manner dependent upon Cas phosphorylation, suggesting that Src is responsible for Cas tyrosine phosphorylation. While all these phenomena occur early after rhodocytin stimulation in a cAMP-resistant manner, tyrosine phosphorylation of Syk and phospholipase Cgamma2, intracellular Ca(2+) mobilization, and platelet aggregation occur later in a cAMP-sensitive manner. Cytochalasin D, which interferes with actin polymerization and blocks receptor clustering, inhibits all the rhodocytin-mediated signals we examined in this study. We suggest that rhodocytin, by clustering GPIa/IIa, activates GPIa/IIa-associated Src, which then mediates downstream activation signals.

Animals↗
PubMed2001

Evidence for a Soft Nuclear Equation-of-State from Kaon Production in Heavy-Ion Collisions.

The production of pions and kaons has been measured in 197Au+197Au collisions at beam energies from 0.6 to 1.5A GeV with the kaon spectrometer at SIS/GSI. The K+ meson multiplicity per nucleon is enhanced in Au+Au collisions by factors up to 6 relative to C+C reactions, whereas the corresponding pion ratio is reduced. The ratio of the K+ meson excitation functions for Au+Au and C+C collisions increases with decreasing beam energy. This behavior is expected for a soft nuclear equation-of-state.

Journal Article↗
PubMed2001

Psychometric evaluation of the exercise self-efficacy scale among Korean adults with chronic diseases.

The purpose of this study was to assess the psychometric properties, appropriateness, and demographic response patterns of an exercise self-efficacy scale for Korean adults with chronic diseases. After assessment of face validity by an expert Korean panel, 249 Korean adults with chronic diseases, ages 18-79 years, were recruited from hospitals or health centers in five Korean cities and surrounding rural areas to complete the questionnaire. In a factor analysis the original 18-item exercise self-efficacy scale converged to one factor without rotation and to three subfactors with rotation: situational/interpersonal factor, competing demands factor, and internal feelings factor. Descriptive analysis showed that Korean adults with chronic diseases perceived they had relatively low exercise self-efficacy, with the situational/interpersonal factor as the lowest factor. Exercise self-efficacy was significantly correlated with gender, education, regular exercise, and frequency of exercise. The exercise self-efficacy scale was shown to be a useful measure of exercise beliefs of Korean adults with chronic diseases.

Adolescent↗
PubMed2001

Signal transduction from bradykinin, angiotensin, adrenergic and muscarinic receptors to effector enzymes, including ADP-ribosyl cyclase.

Muscarinic acetylcholine receptors in NG108-15 neuroblastoma x glioma cells, and beta-adrenergic or angiotensin II receptors in cortical astrocytes and/or ventricular myocytes, utilize the direct signaling pathway to ADP-ribosyl cyclase within cell membranes to produce cyclic ADP-ribose (cADPR) from beta-NAD+. This signal cascade is analogous to the previously established transduction pathways from bradykinin receptors to phospholipase Cbeta and beta-adrenoceptors to adenylyl cyclase via G proteins. Upon receptor stimulation, the newly-formed cADPR may coordinately function to upregulate the release of Ca2+ from the type II ryanodine receptors as well as to facilitate Ca2+ influx through voltage-dependent Ca2+ channels. cADPR interacts with FK506, an immunosuppressant, at FKBP12.6, FK506-binding-protein, and calcineurin, or ryanodine receptors. cADPR also functions through activating calcineurin released from A-kinase anchoring protein (AKAP79). Thus, some G(q/11)-coupled receptors can control cADPR-dependent modulation in Ca2+ signaling.

ADP-ribosyl Cyclase↗