Biomedical subjects

Myung-Hyun Lee

Publications and source records attributed to Myung-Hyun Lee.

5 recordsLinked to original sources

PubMed2005

Fever, use of antibiotics, and acute gastroenteritis during infancy as risk factors for the development of asthma in Korean school-age children.

OBJECTIVE: The hygiene hypothesis postulates that infections early in life might influence the development of asthma later in childhood. However, this hypothesis is controversial. The objective of this study was to determine whether there is a relationship between infection-related risk factors during infancy and development of asthma later in childhood. METHODS: Data were obtained by a nationwide, population-based, cross-sectional study of 26,400 children, 7 to 12 years of age. Parents completed a questionnaire on symptoms of and risk factors for asthma, including the number of fever episodes, acute gastroenteritis, use of antibiotics, and immunization during infancy. The presence of asthma was defined by parental report of "wheeze in the last 12 months" or "asthma ever." Data were analyzed by logistic regression analysis. RESULTS: The occurrence of fever during infancy was weakly associated with the development of asthma (P < 0.05). A higher frequency of episodes of fever was associated with a higher risk of development of asthma. The relationship between antibiotic use during infancy and development of asthma was also significant (P < 0.0001). The adjusted odds ratios of childhood asthma increased in proportion to the number of antibiotic courses during infancy. A history of acute gastroenteritis during infancy increased the risk of developing asthma in later life (P < 0.001). In contrast, immunization in infancy was not related to development of asthma in childhood (P > 0.05). CONCLUSIONS: These data suggest that the development of childhood asthma is associated with episodes of fever, antibiotic use, and acute gastroenteritis during infancy.

Age Factors↗

PubMed2004

Second-harmonic generation in periodically poled nonlinear polymer waveguides.

We demonstrate quasi-phase-matched (QPM) second-harmonic generation (SHG) at the optical communication wavelengths with side-chain polymer waveguides. A ridge waveguide structure is designed to support fundamental mode guiding at both the pump and the second harmonics, leading to a high field overlap integral of the guided modes. The nonlinearity contrast in the +/0 type QPM waveguide is maximized under a QPM poling electrode width of nearly half the coherence length. Using these configurations, we record a normalized SHG efficiency of 2.2% W(-1) cm(-2) in the polymer waveguide.

Journal Article↗

PubMed2004

High-resolution transmission electron microscopy study of Ca(3)Co(4)O(9).

The crystal structure of Ca(3)Co(4)O(9) was investigated using high-resolution transmission electron microscopy (HRTEM) and the image-simulation method. The c(*) was 10.8A and the b parameters were 4.56A for the Ca(2)CoO(3) block and 2.82A for the CoO(2) sheet. The [110] zone axis HRTEM images confirmed that Ca(3)Co(4)O(9) has a modulated layered structure with modulation. For the first time, the atomic positions of the Ca and Co atoms in the Ca(2)CoO(3) block were identified, corresponding to three rows of dark spots in the [110] direction. The observed HRTEM images for Ca(2)CoO(3) agreed well with the calculated images based on the structural model obtained by the Rietveld refinement method.

Calcium↗

PubMed2002

Two-spotted spider mite allergy: immunoglobulin E sensitization and characterization of allergenic components.

BACKGROUND AND OBJECTIVE: Previous investigations demonstrated that two-spotted spider mite (TSM) inhalation causes allergic asthma in agricultural workers. This work investigates whether TSM causes similar problems in the urban population. We determined the sensitization rate to TSM. We also identified immunoglobulin (Ig)E-binding components and evaluated their relationship with house-dust mite (HDM) allergens. METHODS: We carried out skin prick test (SPT) with TSM in 1,806 respiratory allergy patients over 1 year. TSM-IgE was detected by enzyme-linked immunoadsorbent assay (ELISA). TSM-sensitized patients were classified into two groups: patients who were skin test-positive to both TSM and HDM were included in group A and patients who were skin test-positive to TSM only were included in group B. ELISA inhibition test using sera from group A and B were conducted. IgE-immunoblotting was used to identify major allergens. These were purified by 2-dimensional electrophoresis and blotted onto polyvinylidene difluoride, and N-terminal sequences were identified. RESULTS: SPT (> or = 2+ of allergen/histamine) was positive in 358 (19.8%) patients. Twelve (6.6%) showed positive response to TSM only, and 54.5% had positive specific IgE. ELISA inhibition test using sera from two groups showed significant inhibition by TSM with minimal inhibition by HDM. Amino acid sequence of three major allergens was not homologous with any previously characterized allergens. CONCLUSION: IgE-sensitization rate to TSM was 19.8% in respiratory allergy patients. Eleven IgE-binding components and three major allergens were identified. The pIs and amino acid sequences of the major allergens were determined.

Allergens↗

PubMedDate not supplied

Identification of immunoglobulin E binding components of the two-spotted spider mite Tetranychus urticae: allergenic relationships with the citrus red mite and house-dust mite.

The two-spotted mite (TSM) is commonly found on fruit trees, herbaceous plants, and greenhouse flowers. However, a recent investigation indicated that the sensitization rate to TSM was as high as that of house-dust mites (HDMs) in nonfarmers as well as in farmers working in orchards in this country. The aim of this study was to identify immunoglobulin E (IgE)-binding components within TSM and to evaluate the allergenic relationship with the citrus red mite (CRM) and HDM. Sera were collected from eight patients who were not farmers and who had asthma with high serum-specific IgE to the TSM and from unexposed controls showing negative responses to the TSM on skin-prick test. Twelve percent sodium dodecyl sulfate-polyacrylamide gel electrophoresis and immunoblot analysis were applied. To evaluate allergenic relationships with HDMs and CRMs, two kinds of sera pools were used: one (A) showing positive responses to both TSMs and HDMs and the other (B) showing an isolated positive response to TSMs. ELISA inhibition tests using A and B pooled sera were conducted. The TSM-ELISA inhibition test using sera A showed significant inhibition with addition of TSMs and CRMs, partial inhibition with HDMs, and minimal inhibition with other inhalant allergens. The ELISA inhibition test using sera B showed significant inhibition with TSMs and CRMs and minimal inhibition was noted with HDMs as well as other inhalant allergens. Immunoblot analysis using individual sera showed seven IgE-binding components (75, 56, 47, 41, 37, 28, and 14 kDa) and two (75 and 14 kDa) of them were bound to IgE in > 50% of the sera tested. Seven IgE-binding components were identified within the TSM extract and two (75 and 14 kDa) could be considered major allergens. It is suggested that the TSM contains species-specific allergen in addition to shared allergens with CRMs and HDMs.

Adolescent↗