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Biomedical subjects

E Y Lee

Publications and source records attributed to E Y Lee.

At least 19 recordsLinked to original sources
PubMed2006

Evaluation of a modified antimycobacterial susceptibility test using Middlebrook 7H10 agar containing 2,3-diphenyl-5-thienyl-(2)-tetrazolium chloride.

A rapid and accurate antimycobacterial susceptibility test is essential for effective treatment of tuberculosis. The aim of this study was to evaluate a modified method applying 2,3-diphenyl-5-thienyl-(2)-tetrazolium chloride (STC) to the Clinical and Laboratory Standards Institute (CLSI) guideline for susceptibility testing of Mycobacterium tuberculosis. A total of 132 clinical isolates of M. tuberculosis, forty-eight isolates showing resistance to one or more of the first-line antituberculosis drugs, and eighty-four fully susceptible isolates were collected from hospitals of a nationwide distribution from June to September 2004. The modified procedure was conducted basically according to the agar-proportion method described in the CLSI Guideline both with STC 50 mug/mL. The amount of growth in each well was recorded and graded at 2nd and 3rd weeks after inoculation. After 3 weeks of incubation, the diagnostic sensitivity and specificity for the detection of drug-resistant strains of STC-containing agar proportion methods were 100%, except ethambutol-low level resistance, of which the diagnostic sensitivity was 93.4%. After two weeks of incubation in STC-containing agar proportion methods, one hundred of the 107 strain-drug combinations have shown drug resistance, indicating the sensitivity of 93.5%. Especially, all 41 isoniazid-resistant strains and 19 of 21 rifampin-resistant strains (90.5%) could be detected after two weeks of incubation. A modification of the agar proportion method using STC resulted in a reliable and more easily interpretable data, and detected most of resistant strains a week earlier than conventional method.

Agar↗
PubMed2006

Dinucleotide repeat polymorphism in intron II of human Toll-like receptor 2 gene and susceptibility to rheumatoid arthritis.

Human Toll-like receptors (TLRs) participate in innate immune response and signal the activation of adaptive immunity. The presence of a functional intronic polymorphism consisting of guanine-thymine repeats in TLR2 gene was recently reported. Here, we investigated a dinucleotide repeat polymorphism in intron II of TLR2 in Korean patients with rheumatoid arthritis (RA). The numbers of guanine-thymine [(GT)(n)] repeats in intron II of the TLR 2 gene were counted in 183 patients with RA and in 148 healthy controls, using the gene scanning technique. We classified alleles into two subclasses for further analysis, 12-16 GT repeats (S allele) and 17-28 repeats (L allele). By subgroup analysis, we also examined whether the S allele is associated with the presence of shared epitope (SE), rheumatoid factor (RF), joint erosion and extra-articular complications. S-allele frequency was significantly increased in patients with RA than in healthy controls [30.3% vs. 23.0%, P = 0.03, or 1.46, 95% confidence interval (CI) 1.03-2.07], and genotypes containing S alleles were more frequent in patients with RA than in healthy controls (54.4% vs. 46.5%. P = 0.04, or 1.57, 95% CI 1.01-2.42). A skewed S-allele distribution was not found to be related to the presence of SE. Subgroup analysis showed no genotypic or allele frequency differences between patients with/without RF, joint erosion, or extra-articular complications. Genotype containing shorter GT repeats in intron II of the TLR2 gene may confer susceptibility to RA in Koreans.

Adolescent↗
PubMed2006

3D multidetector CT angiographic evaluation of extralobar pulmonary sequestration with anomalous venous drainage into the left internal mammary vein in a paediatric patient.

Pulmonary sequestration is a congenital lung malformation, defined by dysplastic and non-functioning lung tissue lacking normal tracheobronchial connections and accompanied by an anomalous systemic blood supply. Recognition of anomalous arteries and veins in pulmonary sequestration is paramount to making the correct diagnosis. In contrast to intralobar pulmonary sequestration, where anomalous venous drainage is usually into the pulmonary venous system, the pattern of anomalous venous drainage is more varied in extralobar pulmonary sequestration. To the best of our knowledge, anomalous venous drainage to the internal mammary vein in extralobar sequestrations has not been reported. We report an anomalous venous drainage into the internal mammary vein in an extralobar sequestration which was evaluated with 3D multidetector CT angiography.

Breast↗
PubMed2005

Robust one-dimensional metallic band structure of silicide nanowires.

Angle-resolved photoemission (ARP) is employed to investigate the electronic structure of an extremely anisotropic form of nanocrystals--GdSi(2-x) nanowires on Si(100). Using a stepped Si(100) surface, a well-ordered and uniformly oriented array of nanowires is formed along the step edges as confirmed by diffraction and microscopy. The ARP measurement discloses two distinct electronic bands near the Fermi level, which disperse one dimensionally along the nanowires. These bands are metallic with the electron filling of 1/4 and 2/5, respectively, and with the effective mass close to that of a free electron along the wires. The metallicity is robust down to 20 K, in contrast to metallic surface atomic chain systems, paving a way to further studies on one-dimensional physics of metallic nanowires.

Journal Article↗
PubMed2004

Delayed hemolytic transfusion reaction due to anti-Fyb caused by a primary immune response: a case study and a review of the literature.

Delayed hemolytic transfusion reactions (DHTRs) usually occur between 3 and 14 days posttransfusion as a result of a secondary immune response, with a drop in Hb level, fever, jaundice, or hemoglobinuria. DHTRs caused by a primary immune response are particularly rare events, and only a few reports have been known. In this report, we describe an unusual case of a DHTR caused by anti-Fyb in a 42-year-old man, who had no prior history of transfusion. Although it seems to be a rare phenomenon, we suggest that DHTRs by a primary immune response may be considered even in the case of the patient who had typical evidence of hemolysis but who had no previous transfusion history.

Adult↗
PubMed2003

Enhanced cough response to hyperpnea with cold air challenge in chronic cough patients showing increased cough sensitivity to inhaled capsaicin.

BACKGROUND: Although many chronic cough patients have complained of an induced cough by cold air contact, the clinical relevance of cold air to inducing a cough and the diagnostic value of a hyperpnea with cold air (HCA) challenge to detect a hyperreactive cough reflex have not yet been investigated. METHODS: Recordings of cough counts after a 2-min HCA challenge were performed in 49 chronic cough patients and 15 healthy controls. Capsaicin cough provocation tests, which determine the threshold concentration of capsaicin that induces five or more consecutive coughs (C5), were also administered. RESULTS: After comparing the results from the capsaicin cough provocation tests of the patients and the controls, the chronic cough patients were divided into two groups: an increased cough sensitivity (ICS) group (n = 28) (C5 < 32 micromol/l) and a normal cough sensitivity (NCS) group (n = 21) (C5 >or= 32 micromol/l). The median value of induced cough counts after a HCA challenge was 11 coughs in patients with ICS and was a significantly enhanced cough response compared to that of the patients with NCS and healthy controls (four coughs, respectively). CONCLUSIONS: A simple cough provocation test using a HCA challenge may be useful for detecting ICS. It also suggests that hyperreactive cough reflexes may be one of the mechanisms of inducing chronic cough.

Administration, Inhalation↗
PubMed2003

Misidentification of Aeromonas veronii biovar sobria as Vibrio alginolyticus by the Vitek system.

AIMS: To find the cause of misidentification of aeromonads when using the Vitek system. METHODS AND RESULTS: Two Aeromonas veronii biovar sobria isolates were misidentified as Vibrio alginolyticus by the Vitek system. Both strains' identification was confirmed by biochemical testing, API 20E/20NE kits and/or 16S RFLP analysis. Thirty-one known Aeromonas species were tested by the Vitek system using 0.45 and 0.85% saline in the suspension medium. It was not clear whether low salinity causes misidentification of Aeromonas species more frequently. CONCLUSIONS: The specified reaction time may be inappropriately short for some critical biochemical tests of some strains. An ingenious reading strategy regarding incubation time is necessary to improve identification of Aeromonas species by the Vitek system. SIGNIFICANCE AND IMPACT OF THE STUDY: To our knowledge, this is the first report of misidentification of A. veronii biovar sobria as V. alginolyticus in the Vitek system.

Aeromonas↗
PubMed2003

Antitumor effect of intratumoral administration of dendritic cell combination with vincristine chemotherapy in a murine fibrosarcoma model.

A new antitumor therapeutic strategy utilizing the combined effect of chemotherapy and DC (dendritic cell)-based immunotherapy was designed, and the effect of intratumoral injections of unpulsed, immature DCs was evaluated after in vivo pretreatment of vincristine on tumor growth in a murine fibrosarcoma tumor model. Vincristine exerted a much more potent apoptosis/necrosis-inducing effect on MCA-102 tumor cells than on DCs both in vitro and in vivo. Moreover, CD11c, CD40, CD80 and CD86 molecules on DCs were not downregulated after treatment with vincristine either in vitro or in vivo. The growth of tumor significantly regressed in the group which received the combined vincristine chemotherapy with intratumoral administration of DCs in contrast to the untreated group, the group treated with DCs alone, and the group treated with vincristine alone. In particular, an upregulated expression of CD40, CD80 and CD86 molecules on DCs was found in the combination treatment group. Furthermore, the number of CD4+ and CD8+ T cells and the staining intensity of their CD4 and CD8 surface molecules also increased after the combination treatment. Therefore, our results indicate the feasibility of this combination therapy with vincristine chemotherapy and DC-based immunotherapy as an efficient antitumor strategy for the treatment of fibrosarcoma.

Animals↗
PubMed2002

Acute abdominal pain in systemic lupus erythematosus: focus on lupus enteritis (gastrointestinal vasculitis).

OBJECTIVE: To determine the causes of acute abdominal pain in systemic lupus erythematosus (SLE) and to compare the clinical and laboratory data, especially antiphospholipid antibodies and the SLE Disease Activity Index (SLEDAI), between lupus enteritis (gastrointestinal vasculitis) and acute abdominal pain without lupus enteritis in patients with SLE. METHODS: A retrospective study was carried out for all patients admitted with SLE from 1993 to March 2001. The SLEDAI and laboratory data were collected at the time of diagnosis of SLE and at the time of acute abdominal pain. Lupus enteritis (gastrointestinal vasculitis) was diagnosed by clinical investigation and abdominal computed tomographic findings. RESULTS: Chart review identified 175 patients (20 male, 155 female) who had been admitted with SLE. Of these patients, 38 (22%) presented with acute abdominal pain. Lupus enteritis was the most common cause of acute abdominal pain. Patients were divided into three groups: group 1: lupus enteritis (n=17), group 2: acute abdominal pain without lupus enteritis (n=21), and group 3: SLE without acute abdominal pain (n=137). There was no difference in age and sex among the three groups. Antiphospholipid, anti-RNP, anti-Sm, anti-Ro, and anti-La antibodies did not differ among the three groups. There was no difference in the SLEDAI at the time of diagnosis and at the time of acute abdominal pain between groups 1 and 2. Complement, erythrocyte sedimentation rate, C reactive protein, and anti-dsDNA measured at the time of acute abdominal pain did not differ between groups 1 and 2. A drop in the white blood cell count at the time of abdominal pain was more prominent in group 1 than group 2. In lupus enteritis, the jejunum and ileum were the sites most commonly affected. Rectal involvement was rare. Even though four patients relapsed, all the patients with lupus enteritis, including those who relapsed, responded well to corticosteroid. CONCLUSION: Lupus enteritis is the most common cause of acute abdominal pain in SLE. All patients with lupus enteritis responded well to a high dose of a corticosteroid without surgical intervention. The SLEDAI and laboratory data, except leucopenia, do not correlate with the occurrence of lupus enteritis.

Abdominal Pain↗
PubMed2001

Phosphorylation of serines 635 and 645 of human Rad17 is cell cycle regulated and is required for G(1)/S checkpoint activation in response to DNA damage.

ATR [ataxia-telangiectasia-mutated (ATM)- and Rad3-related] is a protein kinase required for both DNA damage-induced cell cycle checkpoint responses and the DNA replication checkpoint that prevents mitosis before the completion of DNA synthesis. Although ATM and ATR kinases share many substrates, the different phenotypes of ATM- and ATR-deficient mice indicate that these kinases are not functionally redundant. Here we demonstrate that ATR but not ATM phosphorylates the human Rad17 (hRad17) checkpoint protein on Ser(635) and Ser(645) in vitro. In undamaged synchronized human cells, these two sites were phosphorylated in late G(1), S, and G(2)/M, but not in early-mid G(1). Treatment of cells with genotoxic stress induced phosphorylation of hRad17 in cells in early-mid G(1). Expression of kinase-inactive ATR resulted in reduced phosphorylation of these residues, but these same serine residues were phosphorylated in ionizing radiation (IR)-treated ATM-deficient human cell lines. IR-induced phosphorylation of hRad17 was also observed in ATM-deficient tissues, but induction of Ser(645) was not optimal. Expression of a hRad17 mutant, with both serine residues changed to alanine, abolished IR-induced activation of the G(1)/S checkpoint in MCF-7 cells. These results suggest ATR and hRad17 are essential components of a DNA damage response pathway in mammalian cells.

Amino Acid Sequence↗
PubMed2001

The proliferative and apoptotic activities of E2F1 in the mouse retina.

The E2F1 transcription factor controls cell proliferation and apoptosis. E2F1 activity is negatively regulated by the retinoblastoma (RB) protein. To study how inactivation of Rb and dysregulated E2F1 affects the developing retina, we analysed wild-type and Rb(-/-) embryonic retinas and retinal transplants and we established transgenic mice expressing human E2F1 in retinal photoreceptor cells under the regulation of the IRBP promoter (TgIRBPE2F1). A marked increase in cell proliferation and apoptosis was observed in the retinas of Rb(-/-) mice and TgIRBPE2F1 transgenic mice. In the transgenic mice, photoreceptor cells formed rosette-like arrangements at postnatal days 9 through 28. Complete loss of photoreceptors followed in the TgIRBPE2F1 mice but not in the Rb(-/-) retinal transplants. Both RB-deficient and E2F1-overexpressing photoreceptor cells expressed rhodopsin, a marker of terminal differentiation. Loss of p53 partially reduced the apoptosis and resulted in transient hyperplasia of multiple cell types in the TgIRBPE2F1 retinas at postnatal day 6. Our findings support the concept that cross-talk occurs between different retinal cell types and that multiple genetic pathways must become dysregulated for the full oncogenic transformation of neuronal retinal cells.

Animals↗
PubMed2001

Identification of the GTP binding site of human glutamate dehydrogenase by cassette mutagenesis and photoaffinity labeling.

It has been reported that the hyperinsulinism-hyperammonemia syndrome is caused by mutations in glutamate dehydrogenase (GDH) gene that affects enzyme sensitivity to GTP-induced inhibition. To identify the GTP binding site(s) within human GDH, mutant GDHs at Tyr-266 or Lys-450 position were constructed by cassette mutagenesis. More than 90% of the initial activities were remained at the concentration of GTP up to 300 microm for the Lys-450 mutant GDHs regardless of their size, hydrophobicity, and ionization of the side chains, whereas the wild type GDH and the Tyr-266 mutant GDHs were completely inhibited by 30 microm GTP. The binding of GTP to the wild type GDH or the mutant GDHs was further examined by photoaffinity labeling with 8-[gamma-(32)P]azidoguanosine 5'-triphosphate (8-N(3)-GTP). Saturation of photoinsertion with 8-N(3)-GTP occurred apparent K(d) values near 20 microm for the wild type GDH or the Tyr-266 mutant GDH, and the photoinsertion of 8-N(3)-[gamma-(32)P]GTP was significantly decreased in the presence of 300 microm GTP. Unlike the wild type GDH or the Tyr-266 mutant GDH, less than 10% of photoinsertion was detected in the Lys-450 mutant GDH, and the photoinsertion was not affected by the presence of 300 microm GTP. The results with cassette mutagenesis and photoaffinity labeling demonstrate selectivity of the photoprobe for the GTP binding site and suggest that Lys-450, but not Tyr-266, is required for efficient binding of GTP to GDH. Interestingly, studies of the steady-state velocity showed that both the wild type GDH and the Tyr-266 mutant GDHs were inhibited by ATP at concentrations between 10 and 100 microm, whereas less than 10% of the initial activities of the Lys-450 mutant GDHs were diminished by ATP. These results indicate that Lys-450, but not Tyr-266, may be also responsible for the ATP inhibition; therefore, ATP bound to the GTP site.

Amino Acid Sequence↗
PubMed2001

Persistent expression of cyclin D1 disrupts normal photoreceptor differentiation and retina development.

The differentiation of neuronal cells in the developing mammalian retina is closely coupled to cell cycle arrest and proceeds in a highly organized manner. Cyclin D1, which regulates cell proliferation in many cells, also drives the proliferation of photoreceptor progenitors. In the mouse retina, cyclin D1 protein normally decreases as photoreceptors mature. To study the importance of the down-regulation of cyclin D1 during photoreceptor development, we generated a transgenic mouse in which cyclin D1 was persistently expressed in developing photoreceptor cells. We observed numerous abnormalities in both photoreceptors and other nonphotoreceptor cells in the retina of these transgenic mice. In particular, we observed delayed opsin expression in developing photoreceptors and alterations in their number and morphology in the mature retina. These alterations were accompanied by disorganization of the inner nuclear and plexiform layers. The expression of cyclin D1 caused excess photoreceptor cell proliferation and apoptosis. Loss of the p53 tumor suppressor gene decreased cyclin D1-induced apoptosis and led to microscopic hyperplasia in the retina. These findings are distinct from other mouse models in which the retinoblastoma gene pathway is disrupted and suggest that the IRBP-cyclin D1 mouse model may recapitulate an early step in the development of retinoblastoma.

Animals↗
PubMed2001

Cloning and sequence analysis of the interleukin-8 gene from flounder (Paralichthys olivaceous).

A cDNA library of mRNA from flounder leukocytes stimulated with bacterial lipopolysaccharide (LPS) and hemagglutinin was constructed to clone cytokine genes of this fish. Initial screening of this library with human cytokine gene probes was not productive and clones with inserts of over 400 nucleotides (nt) were randomly sequenced, and a homologue of the vertebrate interleukin-8 (IL-8) gene was isolated. The flounder IL-8 cDNA encompassed 884 nt, including a coding region of 330 nt. Four cysteines characteristic of CXC chemokines were identified at conserved locations in the putative protein. The deduced amino acid sequence showed 36 and 35% sequence identity with counterpart genes in monkey and human, respectively, and 52% sequence similarity with these genes. However, the putative flounder IL-8 amino acid sequence showed 25% identity and 52% similarity to that of lamprey, the only other piscine IL-8 gene that has been cloned. Flounder IL-8 transcripts were detected in the head-kidney and spleen of LPS-injected flounder and leukocytes stimulated with LPS. It was not detected in the muscle or liver of LPS-injected flounder, tissues taken from non-stimulated flounder and non-stimulated leukocytes.

Amino Acid Sequence↗
PubMed2001

ATM-dependent phosphorylation of human Rad9 is required for ionizing radiation-induced checkpoint activation.

ATM (ataxia-telangiectasia-mutated) is a Ser/Thr kinase involved in cell cycle checkpoints and DNA repair. Human Rad9 (hRad9) is the homologue of Schizosaccharomyces pombe Rad9 protein that plays a critical role in cell cycle checkpoint control. To examine the potential signaling pathway linking ATM and hRad9, we investigated the modification of hRad9 in response to DNA damage. Here we show that hRad9 protein is constitutively phosphorylated in undamaged cells and undergoes hyperphosphorylation upon treatment with ionizing radiation (IR), ultraviolet light (UV), and hydroxyurea (HU). Interestingly, hyperphosphorylation of hRad9 induced by IR is dependent on ATM. Ser(272) of hRad9 is phosphorylated directly by ATM in vitro. Furthermore, hRad9 is phosphorylated on Ser(272) in response to IR in vivo, and this modification is delayed in ATM-deficient cells. Expression of hRad9 S272A mutant protein in human lung fibroblast VA13 cells disturbs IR-induced G(1)/S checkpoint activation and increased cellular sensitivity to IR. Together, our results suggest that the ATM-mediated phosphorylation of hRad9 is required for IR-induced checkpoint activation.

Ataxia Telangiectasia↗
PubMed2001

Extracellular signal-regulated kinase/90-KDA ribosomal S6 kinase/nuclear factor-kappa B pathway mediates phorbol 12-myristate 13-acetate-induced megakaryocytic differentiation of K562 cells.

Two signaling pathways, the extracellular signal-regulated kinase (ERK)/mitogen-activated protein kinase (MAPK)-dependent pathway and the nuclear factor-kappaB (NF-kappaB)-dependent pathway, have been known to mediate megakaryocytic differentiation of K562 cells induced by phorbol 12-myristate 13-acetate (PMA). In this study, we examined whether 90-kDa ribosomal S6 kinase (RSK), known as a substrate of ERK/MAPK and a signal-inducible IkappaBalpha kinase, would link two pathways during the differentiation. RSK1 was activated in a time- and dose-dependent manner during the PMA-induced differentiation. Overexpression of wild-type or dominant inhibitory mutant (D205N) of RSK1 enhanced or suppressed PMA-stimulated NF-kappaB activation and megakaryocytic differentiation as shown by morphology, nonspecific esterase activity, and expression of the CD41 megakaryocytic marker, respectively. In addition, overexpression of the dominant inhibitory mutant (S32A/S36A) of IkappaBalpha inhibited PMA-stimulated and RSK1-enhanced megakaryocytic differentiation, indicating that NF-kappaB mediates a signal for megakaryocytic differentiation downstream of RSK1. PMA-stimulated activation of ERK/MAPK, RSK1, and NF-kappaB and the PMA-induced megakaryocytic differentiation were prevented by pretreatment with PD98059, a specific inhibitor of the mitogen-activated ERK kinase (MEK). Therefore, these results demonstrate that the sequential ERK/RSK1/NF-kappaB pathway mediates PMA-stimulated megakaryocytic differentiation of K562 cells.

Amino Acid Substitution↗