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Biomedical subjects

Y C Hong

Publications and source records attributed to Y C Hong.

At least 19 recordsLinked to original sources
PubMed2006

Bilateral retrocaval ureters with IVC duplication.

We report a rare case of bilateral retrocaval ureters associated with duplicated inferior renal cava. A 69-year-old woman was sent to our emergency room for abdominal pain. Multidetector computed tomogram with multiplanar reconstruction revealed duplicated inferior renal cavae and the bilateral ureters were positioned behind the duplicated inferior vena cava. To our knowledge, coexistence of bilateral retrocaval ureters and duplicated inferior renal cavae has not been reported in the literature.

Aged↗
PubMed2004

Influence of maternal serum levels of vitamins C and E during the second trimester on birth weight and length.

OBJECTIVE: It has been known that maternal oxidative stress during pregnancy plays an important role in fetal growth. However, the association between antioxidant vitamin levels and birth outcomes is not conclusive. We investigated the relationship between maternal serum levels of vitamins C and E during the second trimester and birth weight and length. DESIGN: Prospective cohort study. SETTING: Outpatient-clinic of obstetrics, Ewha Womans University Hospital, South Korea. SUBJECTS AND METHODS: The study subjects were 239 healthy, pregnant women who visited an obstetric clinic for antenatal care, and their singleton live births, in Seoul, Korea, between August 2001 and March 2003. We measured the levels of vitamins C and E in maternal serum during the period 24-28 gestational weeks. Each woman was interviewed for dietary intake by trained interviewers during the second trimester. RESULTS: The serum concentration of maternal vitamin C during the second trimester was significantly associated with birth weight and length in the group of full-term deliveries. An increase of 1 microg/ml in the serum vitamin C level increased the birth weight by 27.2 g and the birth length by 0.17 cm. When we considered the levels of vitamins C and E together in the relationship with birth weight and length, we found that the heaviest birth weight and the longest birth length belonged to the group of upper vitamin C/upper vitamin E. However, dietary intake estimated by 24-h recall method was not a predictor of the levels of serum vitamins C and E. CONCLUSION: We found that maternal serum vitamin C levels during the second trimester were positively correlated with birth weight and length in full-term babies. We also found that birth weight and length were highest when the levels of both vitamins C and E were high. Our results indicate the importance of antioxidant nutrient balance for pregnant women who are exposed to various oxidants through food, drinking water, or inhaled air.

Antioxidants↗
PubMed2003

Exposure to air pollution during different gestational phases contributes to risks of low birth weight.

BACKGROUND: Although there have been growing concerns about the adverse effects of air pollution on birth outcomes, little is known about which specific exposure times of specific pollutants contribute to low birth weight (LBW). METHODS: We evaluated the relationships between LBW and air pollution exposure levels in Seoul, Korea. Using the air pollution data, we estimated the exposure during each trimester and also during each month of pregnancy on the basis of the gestational age and birth date of each newborn. Generalized additive logistic regression analyses were conducted considering infant sex, birth order, maternal age, parental education level, time trend, and gestational age. RESULTS: The monthly analyses suggested that the risks for LBW tended to increase with carbon monoxide (CO) exposure between months 2-5 of pregnancy, with exposure to particles <10 micro m (PM(10)) in months 2 and 4, and for sulphur dioxide (SO(2)) and nitrogen dioxide (NO(2)) exposure between months 3-5. CONCLUSIONS: This study suggests that exposure to CO, PM(10,) SO(2) and NO(2) during early to mid pregnancy contribute to risks for LBW.

Air Pollutants↗
PubMed2001

Helicobacter pylori-associated iron-deficiency anemia in adolescent female athletes.

OBJECTIVE: The objective was to investigate the role of Helicobacter pylori infection in iron-deficiency anemia (IDA) of pubescent athletes. STUDY DESIGN: Blood sampling and a questionnaire survey were performed on 440 regular high school students and 220 athletes of a physical education high school. Hemoglobin, serum iron, total iron-binding capacity, ferritin, and immunoglobulin G antibody to H. pylori were measured to compare the prevalence of IDA and H. pylori infection in the groups. Nutritional analysis and a questionnaire survey for socioeconomic status were undertaken to compare and control for other risk factors that might influence IDA and H. pylori infection in the groups. In those with IDA coexistent with H. pylori infection, we also determined whether IDA can be managed by H pylori eradication. RESULTS: The prevalence rates of IDA, H pylori infection, and H. pylori -associated IDA in female athletes were higher than in the control group. The relative risk of IDA was 2.9 (95% CI, 1.5 to 5.6) for those with H. pylori infection. Athletes who exhibited H. pylori -associated IDA showed significant increases in hemoglobin, iron, and ferritin levels after H. pylori eradication. The subjects in the control group who were treated orally with iron alone showed no significant changes. CONCLUSION: Adolescent female athletes may have development of H. pylori -associated IDA, which can be managed by H. pylori eradication.

Adolescent↗
PubMed2001

Is air pollution a risk factor for low birth weight in Seoul?

Environmental factors contributing to reduced birth weight are of great concern because of the well-known relation of birth weight to infant mortality and adverse effects in later life. We examined the associations between air pollution exposures during pregnancy and low birth weight among all full-term births (gestational age 37-44 weeks) for a 2-year period (January 1996 through December 1997) in Seoul, South Korea. We evaluated these associations with a generalized additive logistic regression adjusting for gestational age, maternal age, parental educational level, parity, and infant sex. We used smoothing plots with generalized additive models to analyze the exposure-response relation for each air pollutant. The adjusted relative risk of low birth weight was 1.08 [95% confidence interval (CI) = 1.04-1.12] for each interquartile increase for carbon monoxide concentrations during the first trimester of pregnancy. The relative risks were 1.07 (95% CI = 1.03-1.11) for nitrogen dioxide, 1.06 (95% CI = 1.02-1.10) for sulfur dioxide, and 1.04 (95% CI = 1.00-1.08) for total suspended particles also for interquartile increase in exposure. Carbon monoxide, nitrogen dioxide, sulfur dioxide, and total suspended particle concentrations in the first trimester of pregnancy period are risk factors for low birth weight.

Adult↗
PubMed2000

Air pollution and daily mortality in seven major cities of Korea, 1991-1997.

The relationship between ambient air pollution and daily mortality in seven major cities of Korea for the period 1991-1997 was examined. These cities account for half of the Korean population (about 22 million). The observed concentrations of sulfur dioxide (SO(2), mean=23.3 ppb), ozone (O(3), mean=23.7 ppb), and total suspended particulates (TSP, mean=77.9 microg/m(3)) during the study period were at levels below Korea's current ambient air quality standards. Generalized additive models were applied to allow for the highly flexible fitting of seasonal and long-term time trends in air pollution as well as nonlinear associations with weather variables, such as air temperature and relative humidity. In city-specific analyses, an increase of 50 ppb of SO(2) corresponded to 1-12% more deaths, given constant weather conditions. The risk of all-cause mortality was estimated to increase by 0.5-4%, with an increase in the 2-day moving average of TSP levels equal to 100 microg/m(3). In multipollutant models with pooled data, we found that the estimated risk of death by SO(2) was notably unaffected by adding the other two pollutants (TSP and O(3)) to the model and was statistically significant in various regression models. The rate ratio (RR) for SO(2) remained elevated, indicating an excess mortality of 3% 50 ppb (RR=1.03; 95% CI, 1.01-1.05). TSP's effect on mortality maintained its significance with O(3), but not with SO(2). This implies that there may be collinearity problems where TSP and SO(2) are included in the same model or that TSP may function less than SO(2) as a surrogate for fine particles in the ambient air of Korea. In conclusion, increased mortality was associated with air pollution at SO(2) levels below the current recommendation for air quality. Further research is needed to clarify the relationship between SO(2) and fine particles in Korea.

Adolescent↗
PubMed2000

Helicobacter pylori infection with iron deficiency anaemia and subnormal growth at puberty.

The purpose of this study was to determine whether Helicobacter pylori infection can contribute to growth deficit, especially in pubescent children who need large amounts of iron for growth. A structured questionnaire was sent to the parents of 532 healthy children aged 10 to 15 years (mean 12.9) to obtain demographic information on the parents and the environment. Of the 532 questionnaires sent out, 375 (70.5%; 170 girls and 205 boys) were returned. After collecting blood samples from participants, haemoglobin, serum iron, total iron binding capacity, serum ferritin, and serum IgG antibodies to H pylori were measured. The effects of risk factors such as H pylori infection, iron deficiency anaemia, sex, socioeconomic status, type of house, and crowding index on growth were analysed using multiple regression analysis. Of 63 H pylori positive children, 18 (28.6%) were below the 25th centile values for height, compared with 63 of 312 (20.2%) H pylori negative children. The prevalence rate of H pylori infection was 15.5% (53 of 343) in children without iron deficiency anaemia and 31.3% (10 of 32) in those affected. The relative risk of short stature was 2.2 (95% confidence interval (CI), 1.0 to 4.8) for iron deficiency anaemia, and 1.4 (95% CI, 0.8 to 2.4) for H pylori infection. The mean height was significantly lower in the group having both H pylori infection and iron deficiency anaemia. Therefore, H pylori infection accompanied by iron deficiency anaemia, rather than H pylori infection per se, might delay pubertal growth.

Adolescent↗
PubMed2000

Influence of genetic susceptibility on the urinary excretion of 8-hydroxydeoxyguanosine of firefighters.

OBJECTIVES: Oxidative DNA damage has been implicated in carcinogenesis. The DNA damage can be assessed from the urinary excretion of the DNA-repair product 8-hydroxydeoxyguanosine (8-OH-dG). The factors were investigated that influenced the excretion of urinary 8-OH-dG in 78 firefighters. METHODS: 53 Out of 78 firefighters were exposed to fire within 5 days of the study and 25 were not. 8-OH-dG was measured by ELISA and the distribution of the genotypes of CYP1A1, CYP2E1, GSTM1, and GSTT1 was measured by polymerase chain reaction. RESULTS: The homozygous wild type frequencies of CYP1A1 MspI, CYP1A1 ile-val, CYP2E1, GSTM1, and GSTT1 were 31.5%, 56.2%, 60.3%, 50.7%, and 53.4%, respectively. The geometric mean of urinary 8-OH-dG was 14.1 ng/mg creatinine in more active firefighters and 12.3 ng/mg creatinine in non-exposed and less active subjects. Significantly increased concentrations of urinary 8-OH-dG were found to be associated with cigarette smoking, and 14% of the variation of 8-OH-dG was explained by cigarettes smoked per day. The CYP1A1 MspI, CYP1A1 ile-val, GSTM1, and GSTT1 genetic polymorphisms were not found to be significantly associated with the urinary excretion of 8-OH-dG. However, the subjects carrying the CYP2E1 mutant type excreted higher concentrations of 8-OH-dG and there was a marginally significant interaction of GSTT1 with firefighting activity. Multiple regression analysis confirmed that smoking was the strongest predictor of excretion of 8-OH-dG. Age, body mass index, and firefighting activity were not significant predictive factors for urinary 8-OH-dG. CONCLUSION: Smoking and CYP2E1 gene polymorphism may be important factors in carcinogenesis and the GSTT1 positive genotype may be a genetic susceptibility factor in firefighters who are exposed regularly to various chemical carcinogens.

8-Hydroxy-2'-Deoxyguanosine↗
PubMed2000

Pulmonary fibrosis in a steel mill worker.

We report a case of pulmonary fibrosis in a 32-year-old man, who had worked at a steel mill and who died of respiratory failure due to interstitial fibrosis despite vigorous treatment. He showed SLE-associated symptoms, such as pleural effusion, malar rashes, discoid rashes, arthritis, leukopenia, and positive antinuclear antibody and anti-histone antibody. However, he did not present anti-DNA antibody. A thoracoscopic lung biopsy showed interstitial fibrosis, chronic inflammation and a small non-caseating granuloma in lung tissues, which could be induced by external agents such as metals. The manganese concentration in the lung tissue was 4.64 microg/g compared to 0.42-0.7 microg/g in the controls. The levels of other metals, such as iron, nickel, cobalt and zinc in patient's lung tissue were higher than those in the controls. The patient was probably exposed to Si and various metal dusts, and the lung fibrosis was related to these exposures. Exposure to Si and metal dusts should be sought in the history of any patient with SLE, especially in a male with pulmonary signs, and if present, exposure should be stopped. In the meantime, steps should be taken to ensure that workers exposure to Si and metal dusts in all environments have adequate protection.

Adult↗
PubMed1999

Variations in urinary 1-hydroxypyrene glucuronide in relation to smoking and the modification effects of GSTM1 and GSTT1.

The measurement of the pyrene metabolite, 1-hydroxypyrene, in human urine has been used to assess recent exposure to polycyclic aromatic hydrocarbons (PAH). The objective of this study was to see whether genetic polymorphisms in metabolic enzymes could explain some of the variation in urinary 1-hydroxypyrene glucuronide (1-OHPG) excretion in relation to smoking. Forty-seven male hospital workers, who were not occupationally exposed to PAH, participated in this study. The urine samples were analyzed for 1-OHPG utilizing immunoaffinity chromatography and synchronous fluorescence spectroscopy. The analysis of GSTM1 and GSTT1 polymorphism was performed by PCR. The 1-OHPG concentration in the urine of the hospital workers was 0.57 +/- 0.85 micromol/mol creatinine, and ranged from 0.02 to 5.04 mciromol/mol creatinine. Cigarette smoking was significantly correlated with urinary 1-OHPG (r = 0.3976, P = 0.0056). The 1-OHPG excretion in GSTM1-deficient smokers was higher than that in GSTM1-positive smokers. On the other hand, 1-OHPG excretion was higher in GSTT1-positive smokers than in GSTT1-deficient smokers. It is important to note the variability of individual PAH metabolite excretion due to different GSTM1 and GSTT1 genotypes.

Adult↗
PubMed1999

Enhancement of DNA damage and involvement of reactive oxygen species after exposure to bitumen with UVA irradiation.

This study was carried out to evaluate whether bitumen cytotoxicity is enhanced when bitumen treatment is combined with UVA exposure. We also evaluated the oxidative processes in bitumen-induced DNA damage, and attempted to identify the DNA damage caused by bitumen and UVA exposures, either alone or in combination. The effects of bitumen and UVA on cell proliferation were examined using HL 60 cells. DNA-protein crosslinks (DPCs) were assessed using a K-SDS assay, and reactive oxygen species formation was detected by 8-OH-dG formation. We evaluated the formations of double-strand breaks (DSB) using lambdaDNA/HindIII and single-strand breaks (SSB) using PM2 DNA. The cytotoxicity assay showed enhanced suppression of cell proliferation when bitumen exposure and UVA exposure were combined. Combined exposure caused significant increases in DPCs over either exposure alone. Incubation of deoxyguanosine (dG) with bitumen or UVA showed an increase in 8-hydroxy-2'-deoxyguanosine (8-OH-dG) levels when compared with controls, and combined exposure enhanced this effect. An evaluation of agarose gel bands showed that DSB and SSB were not formed following exposure to bitumen and UVA. This fact indicates that bitumen and UVA may be involved in genotoxic processes by producing oxygen free radicals and that combined exposure enhances these effects.

Cell Survival↗
PubMed1999

Randomized placebo-controlled trial of Helicobacter pylori eradication for iron-deficiency anemia in preadolescent children and adolescents.

BACKGROUND: A few cases relating H. pylori infection to iron-deficiency anemia have been described recently. We investigated the role of H. pylori infection in iron-deficiency anemia in preadolescent children and adolescents. PATIENTS AND METHODS: We conducted a double-blind, placebo-controlled therapeutic trial in 43 subjects (mean age, 15.4 years) with iron-deficiency anemia. Endoscopy was performed, and biopsy specimens were examined by urease test and histological analysis. Twenty-two of 25 H. pylori-positive patients were assigned randomly to three groups. Group A patients were given oral ferrous sulfate and a 2-week course of bismuth subcitrate, amoxicillin, and metronidazole. Group B patients were given placebo for iron and a 2-week course of triple therapy. Group C patients were given oral ferrous sulfate and a 2-week course of placebo. Iron status was reassessed 4 weeks and 8 weeks after the 2-week regimen ended. RESULTS: Of the 43 subjects with iron-deficiency anemia, 25 (58.1%) had H. pylori in the antrum. Group A and B subjects, who received eradication therapy, showed a significant increase in hemoglobin level as compared with group C subjects at 8 weeks after therapy (p = .0086). CONCLUSIONS: Treatment of H. pylori infection was associated with more rapid response to oral iron therapy as compared with the use of iron therapy alone. Such treatment also led to enhanced iron absorption even in those subjects who did not receive oral iron therapy.

Adolescent↗
PubMed1999

PM(10) exposure, gaseous pollutants, and daily mortality in Inchon, South Korea.

To evaluate the relative importance of various measures of particulate and gaseous air pollution as predictors of daily mortality in Inchon, South Korea, the association between total daily mortality and air pollution was investigated for a 20-month period (January 1995 through August 1996). Poisson regression was used to regress daily death counts on each air pollutant, controlling for time trends, season, and meteorologic influences such as temperature and relative humidity. Regression coefficients of a 5-day moving average of particulate matter less than or = to 10 microm in aerodynamic diameter (PM(10)) on total mortality were positively significant when considered separately and simultaneously with other pollutants in the model. PM(10) remained significant when the models were confined to cardiovascular or respiratory mortality. Sulfur dioxide (SO(2)) and carbon monoxide (CO) were significantly related to respiratory mortality in the single-pollutant model. Ozone exposure was not statistically significant with regard to mortality in the above models, and graphic analysis showed that the relationship was nonlinear. A combined index of PM(10), nitrogen dioxide, SO(2), and CO seemed to better explain the exposure-response relationship with total mortality than an individual air pollutant. Pollutants should be considered together in the risk assessment of air pollution, as opposed to measuring the risk of individual pollutants.

Adolescent↗
PubMed1999

Air pollution and daily mortality in Inchon, Korea.

The association between total daily mortality and air pollution was investigated for a 1-year period (January 1995 to December 1995) in Inchon, Korea. The purpose of this study was to evaluate the relative importance of particulate and gaseous air pollution as predictors of daily mortality. Concentration of total suspended particulates (TSP), inhalable particles (PM10), and gaseous pollutants, such as sulfur dioxide, nitrogen dioxide, ozone, carbon monoxide, were measured daily during the study period. A generalized additive model was used to regress daily death counts on each air pollutant, controlling for time trend and meteorologic influences such as temperature or relative humidity. Total mortality was found to increase 1.2% (95% CI: 0.2 to 2.2%) for each 10 microg/m3 increase in 6-day moving average of TSP, and 1.2% (95% CI 0.2 to 2.1%) for each 10 microg/m3 increase in 5-day moving average of PM10. The association is similar in magnitude to associations between particulate air pollution and mortality found in several other communities in America and Europe. Associations with gaseous pollutants were all statistically insignificant in the generalized additive model. The relative risk of death increased at particulate levels that were well below the current Korean Ambient Air Quality Standard.

Air Pollutants↗
PubMed1998

Measurement of prostaglandin E2 and leukotriene B4 in the gingival crevicular fluid.

UNLABELLED: The arachidonic acid metabolites prostaglandin E2 (PGE2) and leukotriene B4 (LTB4) are inflammatory mediators which are likely to be involved in the pathogenesis of periodontal disease. PGE2 mediates vasodilatation, increases vascular permeability, enhances pain perception by bradykinin and histamine, alters connective tissue metabolism and enhances osteoclastic bone resorption. LTB4 causes the accumulation of inflammatory cells in the inflamed sites, and degranulation of polymorphonuclear leukocytes. OBJECTIVE: To measure gingival crevicular fluid (GCF) levels of PGE2, LTB4 and periodontal health. METHODS: The periodontal condition of 24 subjects was evaluated on the basis of plaque index, gingival index, probing depth, and attachment level. GCF samples were collected from one or two site(s) of each sextant per subject and the volume was measured using Periotron 6000. Samples were then assayed for PGE2 and LTB4 using a competitive enzyme immunoassay. Mean PGE2 and LTB4 levels were determined for each subject and group means compared. RESULTS: Significant differences in the levels of PGE2 and LTB4 were found between patients with periodontitis, and non-periodontitis individuals (P < 0.001). The PGE2/LTB4 levels were positively correlated with the clinical parameters (P < 0.01) and reduced markedly after phase 1 of the periodontal treatment (P < 0.01). The total amount and concentration (ng ml-1) of LTB4 was positively correlated with the gingival index (P < 0.01). CONCLUSIONS: These results indicate that the levels of PGE2 correlated with the severity of the periodontal status, and the levels of LTB4 correlated with gingival inflammation. Thus, our data suggest that the total amounts of PGE2/LTB4 may be good indicators for periodontal inflammation.

Adult↗