Biomedical subjects

Young Yoo

Publications and source records attributed to Young Yoo.

14 recordsLinked to original sources

PubMed2006

Bronchial responsiveness to methacholine and adenosine 5'-monophosphate in preschool children with bronchopulmonary dysplasia.

Bronchial hyperresponsiveness (BHR) is a characteristic feature of asthma, but it is also frequently present in children and adults with chronic obstructive lung diseases. Bronchopulmonary dysplasia (BPD) is a chronic lung disease, most commonly developing after mechanical ventilation and oxygen therapy in premature infants. BHR is usually measured by bronchial challenges, using direct or indirect stimuli. The aim of this study was to evaluate BHR to direct and indirect stimuli in young children with BPD. Methacholine and adenosine 5'-monophosphate (AMP) bronchial challenges were performed on preschool children with BPD (n = 19), using a modified auscultation method. The endpoint was defined as the appearance of wheezing and/or oxygen desaturation. The results obtained were then compared with those of asthmatic (n = 25) and control (n = 23) preschool children. A positive response to methacholine (endpoint concentration, < or = 8 mg/ml) was observed in 89.5% (17/19) of patients with BPD, but a positive response to AMP (endpoint concentration, < or = 200 mg/ml) was observed only in 21.1% (4/19). All patients with asthma responded positively to methacholine, and most (23/25, 92.0%) of them also responded positively to AMP. The majority of controls were unresponsive to both challenges. BHR to methacholine is a frequent finding in preschool-age survivors of BPD, but is usually not accompanied by BHR to AMP. This suggests that most patients with BPD do not have the inflammatory airway response which is characteristic of asthmatic patients.

Adenosine Monophosphate↗

PubMed2006

Bronchial responsiveness to methacholine and adenosine 5'-monophosphate (AMP) in young children with post-infectious bronchiolitis obliterans.

AIM: Bronchial hyperresponsiveness (BHR) is a characteristic feature of asthma, but it is also frequently demonstrated by children and adults with chronic obstructive lung diseases. BHR is usually measured by bronchial challenges using direct or indirect stimuli. The aim of this study was to compare these two types of bronchial challenge in young children with post-infectious bronchiolitis obliterans (BO). METHODS: Methacholine and adenosine 5'-monophosphate (AMP) bronchial challenges were performed on preschool children with post-infectious BO (n=18), those with asthma (n=23) and in controls (n=20), using a modified auscultation method. The endpoint was defined as the appearance of wheezing and/or oxygen desaturation. RESULTS: A positive response to methacholine (an endpoint concentration < or = 8 mg/ml) was observed in 88.9% (16/18) of the patients with post-infectious BO, but a positive response to AMP (an endpoint concentration < or = 200 mg/ml) was observed in only 22.2% (4/18). All patients with asthma responded positively to methacholine, and most (21/23, 91.3%) of them also responded positively to AMP. The majority of the controls were insensitive to both challenges. CONCLUSION: BHR to methacholine is a frequent, but by no means universal, finding in young children with post-infectious BO, but is usually not accompanied by BHR to AMP.

Adenosine Monophosphate↗

PubMed2006

Percentage fall in FVC at the provocative concentration of methacholine causing a 20% fall in FEV1 in symptomatic asthma and clinical remission during adolescence.

BACKGROUND: Many children with asthma go into long-term clinical remission at adolescence, but bronchial hyperresponsiveness (BHR) persists in approximately one half of these subjects. BHR is usually assessed by measuring the provocative concentration of methacholine causing a 20% fall in FEV1 (PC20). The percentage fall in FVC at the PC20 (deltaFVC) has been suggested to be a more useful index of disease severity in asthma than PC20. STUDY OBJECTIVE: The aim of this study was to determine whether deltaFVC is higher in adolescents with symptomatic asthma than in those with clinical remission. PATIENTS AND METHODS: Forty adolescents with symptomatic asthma and 80 adolescents with asthma remission underwent methacholine challenge testing. DeltaFVC and PC20 were measured on the methacholine dose-response curve. RESULTS: The mean (95% confidence interval [CI]) deltaFVC (15.5% [95% CI, 14.1 to 16.9%]) in the symptomatic group (n = 40) was significantly higher (p = 0.017) than that (12.8% [95% CI, 11.5 to 14.1%]) in the BHR-positive (PC20 < 16 mg/mL) remission group (n = 44) or that (11.5% [95% CI, 10.2 to 12.8%]) of the BHR-negative remission group (n = 36), with no difference between the two latter groups (p = 0.581). No significant correlation was found between deltaFVC and PC20 in the symptomatic group (r = -0.156, p = 0.336) or in the whole remission group (r = -0.187, p = 0.097). CONCLUSIONS: Adolescents with symptomatic asthma had a higher deltaFVC than those with clinical remission, irrespective of the presence of BHR in the latter group. This finding suggests that deltaFVC may serve as an adjunct marker for differentiating between asthma persistence and remission during adolescence.

Adolescent↗

PubMed2006

Outbreak of late-onset group B streptococcal infections in healthy newborn infants after discharge from a maternity hospital: a case report.

During a four-week period, four healthy term newborn infants born at a regional maternity hospital in Korea developed late-onset neonatal group B Streptococcus (GBS) infections, after being discharged from the same nursery. More than 10 days after their discharge, all of the infants developed fever, lethargy, and poor feeding behavior, and were subsequently admitted to the Korea University Medical Center, Ansan Hospital. GBS was isolated from the blood cultures of three babies; furthermore, GBS was isolated from 2 cerebral spinal fluid cultures. Three babies had meningitis, and GBS was isolated from their cerebral spinal fluid cultures. This outbreak was believed to reflect delayed infection after early colonization, originating from nosocomial sources within the hospital environment. This report underlines the necessity for Korean obstetricians and pediatricians to be aware of the risk of nosocomial transmissions of GBS infection in the delivery room and/or the nursery.

Cross Infection↗

PubMed2005

STAR proteins quaking-6 and GLD-1 regulate translation of the homologues GLI1 and tra-1 through a conserved RNA 3'UTR-based mechanism.

The binding of the STAR protein GLD-1 to an element in the tra-2 3' untranslated region (3'UTR), called the TGE (tra GLI element), represses tra-2 translation, allowing for hermaphrodite spermatogenesis in Caenorhabditis elegans. GLD-1 is a member of the STAR family that includes the mammalian quaking (Qk) proteins. Here, we show that the 3'UTR of the nematode homologue of GLI1, called tra-1, also contains a TGE, through which translation is regulated by GLD-1. We find that GLD-1 activity is required for proper TRA-1 protein expression in hermaphrodites. RNA gel shift assays show that GLD-1 binds the predicted sites. Using reporter transgenes, we show that the human GLI1 (hGLI1) 3'UTR controls translation in the mouse embryo. We demonstrate that the addition of the mouse QK isoform-6 (QKI-6) protein to a mammalian cell line that lacks QKI-6 can confer regulation on reporter and GLI1 mRNAs in a TGE-specific manner, and reduction of QKI-6 activity with siRNA disrupts translational control. Further, siRNA knockdown of QKI-6 increases the activity of a reporter transgene that monitors the transcriptional activity of mouse Gli1 (mGli1) and increases mouse Gli1 protein. We show by immunoprecipitation that QKI-6 antibody specifically co-purifies TGE-containing mRNAs in ribonucleoproteins. Thus, we find that the mouse QKI-6 protein acts through the mGli1 and hGLI1 RNAs to repress translation. Our results suggest that STAR family-dependent translational control of GLI mRNAs is ancient, and that it existed before the division of nematodes and mammals.

3' Untranslated Regions↗

PubMed2005

Coincidence of atopy and its profile (monosensitization/polysensitization) between sibling pairs.

BACKGROUND: Results of epidemiologic studies have shown that childhood atopy is probably a hereditary disorder. In the atopic population, some individuals are sensitized to only 1 class of allergens (monosensitized), whereas others are sensitized to more than 1 class of allergens (polysensitized). OBJECTIVE: To investigate whether atopy and its profile (monosensitization/polysensitization) tend to coincide in sibling pairs. METHODS: We evaluated sensitization to 5 classes of aeroallergens (house dust mites, animal danders, pollens, molds, and cockroach) using skin prick testing in 564 children with symptoms suggestive of allergic diseases (index children) and their paired siblings. RESULTS: The frequency of sibling atopy was highest (56.8%) for polysensitized index children (n=222), intermediate (45.4%) for monosensitized index children (n=196), and lowest (30.8%) for nonsensitized index children (n=146). The proportion of polysensitization among atopic siblings was significantly higher for polysensitized (47.6%) than for monosensitized (32.6%) index children. Polysensitized index children were found to more frequently have polysensitized siblings (27.0%) than were monosensitized index children (14.8%), with an odds ratio of 2.13 (95% confidence interval, 1.30-3.49), whereas the likelihood of having a monosensitized sibling was similar for monosensitized and polysensitized index children. CONCLUSION: These data suggest a coincidence of atopy and its profile in terms of monosensitization and polysensitization in sibling pairs, although the relative importance of genetic and environmental influences requires further study.

Allergens↗

PubMed2005

Bronchial responsiveness and serum eosinophil cationic protein levels in preschool children with recurrent wheezing.

BACKGROUND: Bronchial hyperresponsiveness is a universally recognized phenomenon of asthma, and increased levels of eosinophil cationic protein (ECP) have been identified in the serum of patients with asthma. OBJECTIVES: To investigate whether enhanced bronchial responsiveness and elevated serum ECP levels are associated with recurrent wheezing in preschool children and to examine the possible relationship between these 2 variables. METHODS: We recruited 130 children aged 4 to 6 years: 59 with at least 3 episodes of wheezing in the previous year (current wheezers), 38 with a documented history of wheezing before 3 years of age but no subsequent wheezing episodes (past wheezers), and 33 who had never experienced wheezing (nonwheezers). The children underwent methacholine bronchial provocation tests using a modified auscultation method and blood sampling for the measurement of ECP levels. RESULTS: Current wheezers showed greater bronchial responsiveness than past wheezers and nonwheezers, as demonstrated by lower provocation concentrations that caused audible wheeze and lower provocation concentrations that caused a decline in oxygen saturation of at least 5% from baseline. Likewise, current wheezers had higher serum ECP levels than the other 2 groups. Among current wheezers, ECP levels showed a significant negative correlation with provocation concentrations that caused oxygen desaturation and a marginally significant correlation with provocation concentrations that caused audible wheeze. CONCLUSIONS: Enhanced bronchial responsiveness and elevated serum ECP levels are associated with recurrent wheezing in 4- to 6-year-old children. These results suggest that wheezing during preschool years may be phenotypically similar to wheezing in older children.

Asthma↗

PubMed2005

Peak expiratory flow variability and exercise responsiveness in methacholine-hyperresponsive adolescents with asthma remission.

The aim of this study was to investigate whether bronchial hyperresponsiveness in adolescents with long-term asthma remission is associated with increased peak expiratory flow (PEF) variability and/or increased bronchial response to exercise (BRE). Twenty-nine adolescents with asthma remission (neither symptoms nor any medication used during the previous two years), but with persistent methacholine hyperresponsiveness (PC20 < 18 mg/mL; remission group), 29 methacholine PC20-matched adolescents with symptomatic asthma (symptomatic group), and 20 healthy subjects (control group) were studied. Subjects recorded PEF twice daily for 14 days and PEF variability, expressed as amplitude % mean, was calculated. Subjects also underwent a standardized exercise challenge; BRE was defined as a maximal % fall in FEV1 within 30 min after exercise. The mean (+/- SD) PEF variations in the symptomatic group and in the remission group were 12.10 +/- 6.35% and 10.02 +/- 4.73%, respectively, which were significantly higher than that (5.94 +/- 2.44%) of the control group. On the other hand, the degree of BRE (7.36 +/- 3.85%) in the remission group was significantly lower than that (22.31 +/- 10.50%) of the symptomatic group, and similar to that (5.98 +/- 2.70%) of the control group. Methacholine hyperresponsiveness in asthma remission during adolescence is associated with increased PEF variability but not with increased BRE.

Adolescent↗

PubMed2005

Bronchoalveolar lavage eosinophil cationic protein and interleukin-8 levels in acute asthma and acute bronchiolitis.

OBJECTIVE: In this study, we measured the levels of eosinophil cationic protein (ECP) and interleukin (IL)-8 in bronchoalveolar lavage (BAL) fluid from patients with acute asthma and acute bronchiolitis, to determine any similarities or dissimilarities in the profiles of these biochemical markers in the two diseases. METHODS: BAL fluids were obtained from children with acute asthma (n=16), infants with acute bronchiolitis caused by respiratory syncytial virus (n=18), and control subjects (n=14). Children with asthma were selected to be free of viral infection. BAL cell counts and differentials were determined, and ECP and IL-8 levels were measured by radioimmunoassay and ELISA, respectively. RESULTS: ECP levels in BAL fluids were significantly higher in the asthma group than in the bronchiolitis (P<0.01) or control (P<0.0001) groups. However, IL-8 levels were significantly higher in the bronchiolitis group than in the asthma (P<0.01) or control (P<0.001) groups. IL-8 levels in the asthma group and ECP levels in the bronchiolitis group were similar to those of the control group. CONCLUSION: This difference in profiles of ECP and IL-8 in acute asthma and acute bronchiolitis, together with a different inflammatory cell pattern, suggests that the nature of the inflammatory process within the lower respiratory tract may be distinctive in these two diseases.

Acute Disease↗

PubMed2005

Maximal airway response to methacholine in cough-variant asthma: comparison with classic asthma and its relationship to peak expiratory flow variability.

BACKGROUND: In asthmatic subjects, not only airway sensitivity but maximal airway response are increased on the dose-response curve to methacholine, and peak expiratory flow (PEF) variability is closely related to airway hypersensitivity and maximal airway response. OBJECTIVE: The aims of this study were to compare the prevalence and the level of maximal response plateau between patients with cough-variant asthma (CVA) and those with classic asthma (CA), and to examine the relationship between airway hypersensitivity or maximal airway response and PEF variability in patients with CVA. METHODS: A high-dose methacholine inhalation test was performed on 83 patients with CVA and on 83 patients with CA matched for provocative concentration of methacholine causing a 20% fall in FEV1 (PC20). PEF was recorded in the morning and evening for 14 consecutive days in 78 CVA patients, and the amplitude percentage mean was used to express the diurnal PEF variation. RESULTS: Fifty-two CVA subjects (62.7%) but only 33 CA subjects (39.8%) showed a maximal response plateau. This difference was significant after correction by the Bonferroni method (corrected p = 0.024). Subjects in the CVA and CA groups showing a plateau had significantly different plateau levels (38.0 +/- 5.9% vs 42.9 +/- 3.9%, corrected p = 1.0 x 10(-4)). In patients with CVA, no significant relationship was found between PC20 and PEF variability. However, the absence of a maximal response plateau and a higher plateau level were associated with increased PEF variability. CONCLUSIONS: Maximal airway response may be an important confounder in the relationship between airway hypersensitivity and the clinical expression of asthma. The identification of a maximal response plateau and the level of this plateau in patients with CVA provide information relevant to PEF variability.

Age Factors↗

PubMed2005

Distributions of antibody titers to Mycoplasma pneumoniae in Korean children in 2000-2003.

The aim of study was to describe Mycoplasma pneumoniae epidemics in a hospital-based population. Special attention was paid to the relationship between antibody titer to M. pneumoniae and sex, age, and atopy. During the eight 6-month periods between January 2000 and December 2003, serum samples were obtained from 1,319 Korean children who presented with respiratory symptoms, and were examined for antibodies to M. pneumoniae using the indirect particle agglutination test. Geometric mean antibody titers peaked in the second half of 2000 and then decreased gradually, a second peak occurred in the second half of 2003. Likewise, the frequency of high antibody titers (> or =1:640) also peaked during these two periods. Antibody titers in children aged 0-3 yr were lower than in older children during both peak periods and for 2 yr after the first peak. Sex and atopy had no effect on antibody titers. During the years 2000-2003, geometric mean antibody titers and the frequencies of high antibody titers varied with time. These changes suggest a cyclic pattern of M. pneumoniae infection, with two epidemic peaks separated by 3 yr.

Adolescent↗

PubMed2004

Current treatment for primary ciliary dyskinesia conditions.

Primary ciliary dyskinesia (PCD) is a heterogeneous group of conditions characterised by ultrastructural defects of the cilia, which result in impaired mucociliary clearance. Although the incidence of PCD is low, early recognition and prompt management are important in order to prevent unnecessary morbidity, the progression of bronchiectasis and the deterioration of lung function. As the underlying defect in PCD cannot be corrected, the mainstay of therapy remains effective clearance of airway secretions and antibiotic therapy of respiratory tract infections. This paper highlights new developments in the field that have implications for the future management of PCD. These include beta-adrenergic agonists, arginine, uridine-5'-triphosphate, hypertonic saline and recombinant human DNase. It is to be hoped that these treatment modalities will have a therapeutic role in PCD.

Adrenergic beta-Agonists↗

PubMed2003

Bronchial hyperresponsiveness in adolescents with long-term asthma remission: importance of a Family history of bronchial hyperresponsiveness.

BACKGROUND: The mechanisms responsible for bronchial hyperresponsiveness (BHR) in symptomatic asthma include genetic predisposition and airway inflammation, but the causes of BHR in adolescents with asthma remission are poorly understood. It has been shown that BHR in adolescents with asthma remission was not reduced by prolonged treatment with inhaled corticosteroids, in contrast to the BHR of symptomatic asthma. OBJECTIVE: The aim of this study was to investigate whether family history of BHR may contribute to the persistence of BHR in asthma remission during adolescence. METHODS: One hundred twenty-six adolescents with long-term asthma remission (neither symptoms nor any medication used during the previous 2 years) and their parents underwent a methacholine inhalation test. The provocative concentration of methacholine causing a 20% fall in FEV(1) (PC(20)) and the bronchial responsiveness (BR) index were calculated for each individual. RESULTS: Sixty-nine adolescents (54.8%) were found to have persisting BHR (PC(20) < 18 mg/mL). The frequency of BHR and the BR index were significantly higher in parents (n = 138) of the BHR-persisting group (28.3% and 1.150 +/- 0.103, respectively [mean +/- 1 SD]) than in parents (n = 114) of BHR-nonpersisting group (16.7% [p = 0.030] and 1.124 +/- 0.088 [p = 0.029], respectively). Furthermore, adolescents (n = 56) with at least one BHR-positive parent were found to have a higher frequency of BHR (66.1% vs 45.7%, p = 0.023) and a higher BR index (1.244 +/- 0.090 vs 1.204 +/- 0.082, p = 0.011) than adolescents (n = 70) with non-BHR parents. CONCLUSION: Our results suggest that adolescents in asthma remission are more likely to have BHR when there is a family history of BHR. Further studies are needed to examine the possible involvement of genetic factors in the BHR of adolescents in asthma remission.

Adolescent↗

PubMedDate not supplied

The relationship between delta-forced vital capacity (percent fall in forced vital capacity at the PC20 dose of methacholine) and the maximal airway response in patients who have mild asthma.

Airway hypersensitivity is routinely evaluated by measuring the concentration (PC20) of inhaled methacholine or histamine that causes a 20% fall in forced expiratory volume in 1 second (FEV1). It has been suggested that a percentage fall in forced vital capacity (FVC) measured at the PC20 dose of inhaled agonist (deltaFVC) is a potentially useful clinical measure in patients who have asthma because it provides indirect information about gas trapping and therefore the maximal airway response. The relationships between serum eosinophil cationic protein (ECP) levels and the maximal airway response or deltaFVC are largely unknown. The aims of this study were to determine whether deltaFVC is correlated with the degree of maximal airway response and to examine the relationships between serum ECP and deltaFVC or maximal airway response in patients who have mild asthma. Fifty-eight patients with mild asthma underwent high-dose methacholine challenge testing. The PC20, maximal airway response, and deltaFVC were measured on the methacholine dose-response curves. Serum ECP levels also were determined. Subjects without a maximal response plateau (n = 33) had a significantly higher level of deltaFVC (17.9 +/- 4.1%) than subjects with a plateau (n = 25; 14.9 +/- 4.8%). A significant correlation was found between deltaFVC and the level of maximal response plateau (r = 0.446; p = 0.026). Not only methacholine PC20 but also maximal airway response or deltaFVC had no relationships with serum ECP levels. Our results suggest that deltaFVC can be used as a surrogate marker of maximal airway response in patients who have mild asthma and that neither maximal airway response nor deltaFVC reflects blood eosinophil activation any more than methacholine PC20.

Adolescent↗