Biomedical subjects

Ki-Young Kim

Publications and source records attributed to Ki-Young Kim.

12 recordsLinked to original sources

PubMed2006

Regulation of metal transporters by dietary iron, and the relationship between body iron levels and cadmium uptake.

Iron (Fe) plays essential roles in biological processes, whereas cadmium (Cd) is a toxic and non-essential metal. Two metal transporters, divalent metal transporter 1 (DMT1) and metal transporter protein 1 (MTP1), are responsible for Fe transport in mammals. Here, we studied the effect of dietary Fe on the expression of these metal transporters in peripheral tissues, and the uptake by these tissues of Cd. Mice were fed an Fe-sufficient (FeS: 120 mg Fe/kg) or Fe-deficient (FeD: 2-6 mg Fe/kg) diet for 4 weeks. The total Fe levels in the body were evaluated by measuring tissue Fe concentrations. Tissue Cd concentrations were determined 24 h after the mice received a single oral dose of Cd. Animals fed a FeD diet showed depletion of body Fe levels and accumulated 2.8-fold higher levels of Cd than the FeS group. Quantitative real time RT-PCR revealed that whereas DMT1 and MTP1 were both ubiquitously expressed in all FeS peripheral tissues studied, DMT1 was highly expressed in brain, kidney, and testis, whereas MTP1 was highly expressed in liver and spleen. Depletion of the body Fe stores dramatically upregulated DMT1 and MTP1 mRNA expression in the duodenum as well as moderately upregulating their expression in several other peripheral tissues. The iron response element positive isoform of DMT1 was the most prominently upregulated isoform in the duodenum. Thus, DMT1 and MTP1 may play an important role in not only maintaining Fe levels but also facilitating the accumulation of Cd in the body of mammals.

Animals↗

PubMed2006

Rehmannia glutinosa activates intracellular antioxidant enzyme systems in mouse auditory cells.

Steamed roots of Rehmannia glutinosa (R. glutinosa) have been traditionally used in Oriental medicine for the treatment of auditory diseases such as tinnitus and hearing loss. To investigate whether the ethanol extract of steamed roots of R. glutinosa (SRG) increases activity of antioxidant enzymes and the level of glutathione (GSH), we measured activities of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPX), and glutathione reductase (GR) and GSH level in HEI-OC1 cells after treatment with 5-50 microg/ml of SRG. The SOD and CAT activities were significantly increased in the presence of SRG compared to the control group. Maximal activities of SOD and CAT were observed in these cells exposed to 10 microg/ml of SRG. The GPX activity also increased dramatically in response to the treatment with SRG in a dose-dependent manner. The GR activity was only increased in the presence of 50 microg/ml of SRG compared to the control group. The level of GSH gradually increased in the presence of 5-50 microg/ml of SRG. In the cytotoxicity test, 5-50 microg/ml of SRG did not show any significant cytotoxicity. These results suggest that the traditional use of R. glutinosa for the treatment of auditory diseases may be explained, in part, by activation of intracellular antioxidant enzyme systems. Further studies are necessary to clarify the active constituents of SRG responsible for such biomolecular activities.

Animals↗

PubMed2005

Alterations of protein expression in macrophages in response to Candida albicans infection.

Although macrophages are an important first line of cellular defense, they are unable to effectively kill phagocytosed C. albicans. To determine the physiological basis of this inability, we investigated the alterations of macrophage proteins caused by C. albicans infection. Since the formation of C. albicans hyphae caused cell death, proteins were prepared 3 h after infection and examined by two-dimensional gel electrophoresis (2-DE). The most prominent changes were in glycolytic enzymes, which could have caused energy depletion of the infected cells. Also changed were proteins involved in maintenance of cellular integrity and NO production. Treatment of the macrophages with either cytochalasin D or taxol did not alter their inability to kill C. albicans. Our results indicate that multiple factors contribute to cell death as the pathogenic form of C. albicans becomes fully active inside macrophage cells.

Animals↗

PubMed2005

Effects of lacidipine on vascular responses in patients with coronary artery disease.

BACKGROUND: To evaluate the effects of the calcium channel blocker lacidipine on vascular responses, such as endothelial function and carotid intima-media thickness (IMT), and on levels of high-sensitivity C-reactive protein (hs-CRP) in patients with coronary artery disease (CAD). METHODS: Endothelial function was assessed by measuring the flow-mediated vasodilation (FMD) of the brachial artery and IMT was measured in the common, bifurcating, and in the internal carotid artery by using high-resolution ultrasound. The study population consisted of 96 consecutive patients [mean age 60 years, male (n) = 70] who showed at least one coronary artery narrowed by more than 50% (coronary angiography). These patients were randomly assigned to lacidipine treatment (4 mg/day, n = 48) or to a placebo (n = 48). We measured FMD, IMT, and hs-CRP prior to and after 6 months of treatment and following coronary angiography in all patients. RESULTS: Clinical and medical history revealed no significant differences between the groups. IMT of the common carotid artery was significantly diminished from 0.92 +/- 0.15 to 0.87 +/- 0.15 mm 6 months after treatment with lacidipine (p < 0.005). However, IMT of any region in the carotid artery did not show any significant changes in the placebo group. Endothelial function and hs-CRP levels were slightly improved (insignificant) in the lacidipine group. In the placebo group, there were no significant changes. CONCLUSION: Lacidipine leads to a significant reduction of the common carotid artery IMT as well as to a decrease in markers of inflammation in patients with CAD during a relatively short period (6 months).

Blood Flow Velocity↗

PubMed2005

Are league tables controlling epidemic of caesarean sections in South Korea?

OBJECTIVE: To assess the impact of the publication of hospital caesarean section rates on the reduction of these rates in South Korea, and explore associated factors contributing to the decrease. DESIGN: Observational study. SETTING: South Korea. SAMPLE: Two hundred and sixty-three hospitals in South Korea. METHODS: The caesarean section rates of 263 hospitals, before and after the release of caesarean section rates to the public, were obtained. The factors influencing the reduction in hospital caesarean section rates were also explored using multiple logistic regression. MAIN OUTCOME MEASURE: Hospital caesarean section rates. RESULTS: After the release of information in 2000, the total (clinic and hospital) caesarean section rates in 2000 and 2001 decreased to 38.6% and 39.6%, respectively, from 43.0% in 1999. Caesarean section rates for hospitals were 45.9%, 42.7% and 44.6% in 1999, 2000 and 2001, respectively. Hospitals with the highest baseline caesarean section rates (OR 9.4, 95% CI 4.2-21.0) and highest number of deliveries (OR 8.1, 95% CI 2.1-31.1) were significant factors contributing independently to a decrease in caesarean section rates. Market share, competition, characteristics of revenue generation and ownership did not significantly influence the change of rates. CONCLUSION: The public release of information on caesarean section rates in Korea has reversed the ever-increasing trend in these rates. Hospitals with pre-existing high caesarean section rates or a larger number of deliveries were influenced by the information release and could be the main targets for interventions to decrease these rates.

Cesarean Section↗

PubMed2004

Molecular cloning and biochemical characterization of Candida albicans acyl-CoA:sterol acyltransferase, a potential target of antifungal agents.

To determine whether Candida albicans acyl CoA:sterol acyltransferase (ASAT) can be a potential target enzyme for the protoberberine derivative (HWY-289), we have isolated a gene encoding Ca-ASAT and examined inhibitory effects of HWY-289 on the overexpressed Ca-ASAT. HWY-289 specifically inhibits Ca-ASAT in a non-competitive manner in vitro (IC(50) [9.2microM], K(i) [5.15microM]). The cloned CaARE2 gene (1830 nucleotides [nt]) encodes active Ca-ASAT protein that exhibits a calculated molecular mass of 71.3kDa. The amino acid sequence of CaAre2p is 33.4% and 35.1% identical to those of Saccharomyces cerevisiae ScAre1p and ScAre2p homologues, respectively. Recombinant and endogenous Ca-ASAT displayed identical patterns of inhibition upon exposure to HWY-289 and a preference for cholesterol and oleoyl-CoA as substrates. Northern blot analysis showed that CaARE2 was activated by HWY-289, but not by CI-976 (a human acyl-coenzyme A:cholesterol acyltransferase inhibitor), in a dose-dependent manner (up to 5mg/L), suggesting different selectivities of action between HWY-289 and CI-976 on Ca-ASAT activity.

Acyl Coenzyme A↗

PubMed2004

Impact of left ventricular ejection fraction on endothelial function in patients with coronary artery disease.

BACKGROUND: Endothelial dysfunction is present in patients with coronary artery disease (CAD) or with congestive heart failure. HYPOTHESIS: This study was performed to evaluate the impact of systolic heart function on endothelial function in patients with CAD. METHODS: The study population consisted of 283 consecutive patients (mean age 59 years, 176 men) undergoing coronary angiography. Endothelial function was assessed by measuring flow-mediated vasodilation (FMD) of the brachial artery. RESULTS: Patients (n = 236) with an ejection fraction (EF) > or = 55% on routine echocardiogram were younger (mean age 58 vs. 62 years), showed a lower prevalence of diabetes (15 vs. 38%) and myocardial infarction (13 vs. 66%), and showed a higher FMD (4.8 +/- 2.4 vs. 4.0 +/- 2.0%, p < 0.05) than patients (n = 47) with an EF < 55%. The correlation coefficient between FMD/endothelial function and EF/systolic heart function was 0.149 (p < 0.02) in the overall study population. Multivariate analysis showed that of age, gender, frequency of diabetes mellitus, myocardial infarction, and CAD extent, EF was the only significant independent parameter correlating with FMD in patients with CAD. CONCLUSIONS: Compared with the other tested risk factors, EF surprisingly was the only significant independent parameter correlating with endothelial function in patients with CAD. Our results support the view that endothelial function is an independent prognostic factor in patients with CAD.

Brachial Artery↗

PubMed2004

Development and evaluation of digital subtraction radiography computer program.

OBJECTIVE: We developed a new program for digital subtraction radiography (DSR) having useful functions to get the DSR image more accurately and efficiently. The purpose of this study was to evaluate the accuracy of the DSR image acquired using the new program as compared with the ready-made program. STUDY DESIGN: Four observers performed the DSR process using our program and the ready-made program for digital intraoral radiographs taken from incisor, premolar, and molar regions. The statistical difference was evaluated between the programs, between the observers, and between the regions. RESULTS: The DSR image using our program was superior to that with the ready-made program in all the observers and all the radiographed regions. Also, there was the statistical difference among the observers, especially in our program. CONCLUSION: The DSR image using the new program was very accurate compared with ready-made program, so the program was useful to get an accurate DSR image.

Humans↗

PubMed2004

Effects of low-dose atorvastatin on vascular responses in patients undergoing percutaneous coronary intervention with stenting.

BACKGROUND: The primary endpoint of this study was to evaluate the effects of low-dose atorvastatin on carotid intima-media thickness (IMT) and endothelial function, and the secondary endpoint comprised restenosis and target lesion revascularization (TLR) in patients undergoing percutaneous coronary intervention (PCI) with stenting for the treatment of coronary artery disease. METHODS: Two hundred five consecutive patients (mean age, 60 years) undergoing PCI were prospectively randomized to usual therapy (control group, n = 100) or to 10 mg of atorvastatin daily plus usual therapy (statin group, n = 105). Carotid IMT, endothelial function (flow-mediated dilatation [FMD] of the brachial artery), and coronary angiograms were taken before the study and 6 months after randomization. The 6-month follow-up measurements of the above factors were obtained in 83 patients (83%) of the control group and in 97 patients (92%) of the statin group. RESULTS: No significant differences were noted in the baseline clinical and angiographic findings in either group. FMD was significantly improved during the 6 months in the statin group (4.38% +/- 1.7% vs 4.85% +/- 1.6%, P = .003), but did not change in the control group. Carotid IMT did not show any significant changes at 6 months in either group. There was a trend in favor of statin in terms of restenosis rate (26.8% vs 36.1%, P = .177) and TLR rate (18.6% vs 25.3%, P = .274). The changes of FMD were significantly correlated with the changes of total cholesterol and the changes of low-density lipoprotein, respectively (r = -0.336, P = .009, and r = -0.310, P = .046). CONCLUSION: Low-dose atorvastatin reduces endothelial dysfunction as measured by FMD, which coincides with the beneficial effects on lipid profiles, and can decrease restenosis and TLR rate in patients undergoing PCI with stenting.

Aged↗

PubMed2003

Significance of the intima-media thickness of the thoracic aorta in patients with coronary atherosclerosis.

BACKGROUND: The prevalence and clinical significance of atherosclerotic aortic disease have now been documented in a variety of patient populations by use of transesophageal echocardiography (TEE). There are many reports that atherosclerotic aortic plaques detected by TEE are a marker for coronary artery disease (CAD). HYPOTHESIS: The study was undertaken to evaluate the significance of the intima-media thickness (IMT) and formation of atherosclerotic plaques of the thoracic aorta (TA) in patients with CAD, especially in terms of a correlation between the IMT of the TA and the extent of coronary atherosclerosis. METHODS: The IMT of the TA was measured using TEE. The study population comprised 100 patients (68 men, mean age 59 years). The extent of coronary atherosclerosis was divided into four groups (0, 1, 2, 3) according to the number of coronary arteries narrowed > or = 50%. RESULTS: There was no significant difference in the IMT of the ascending TA according to the presence of significant (> 50% narrowed) coronary stenosis, but there was a significant difference in the IMT of the descending TA (1.39 vs. 1.88 mm, p = 0.005). There was a significant correlation between the extent of coronary atherosclerosis and the IMT of the ascending and descending TA (r = 0.24, p < 0.05; r = 0.352, p < 0.001, respectively). The plaques in the TA were seen in 7, 41, 52, and 65% of patients in Groups 0, 1, 2, and 3, respectively. Among atherosclerosis risk factors, hyperlipidemia was the only factor analyzed that affected the IMT of the descending TA (2.11 vs. 1.78 mm, p < 0.05). CONCLUSION: The IMT of the TA correlates significantly with coronary atherosclerosis, and correlation of the descending TA IMT with coronary atherosclerosis is better than that of ascending TA IMT. Age is associated with coronary atherosclerosis, and TA IMT and hyperlipidemia are associated with descending TA IMT. Therefore, although TEE is not recommended for measuring TA IMT or for evaluating aortic plaques in patients with CAD, measurement of TA IMT as well as carotid artery IMT is very helpful for understanding the extent of coronary atherosclerosis.

Adult↗

PubMed2003

Comparison of outdoor and indoor mobile source-related volatile organic compounds between low- and high-floor apartments.

The current study examined the hypothesis that there may be vertical variation in mobile source-related volatile organic compound (VOC) concentrations in high-rise apartment buildings. One hundred twelve homes in 56 high-rise apartment buildings with 10 or more stories participated in the study. Both the outdoor and the indoor air concentrations of three VOCs [methyl-tertiary butyl ether (MTBE), benzene, and toluene] were significantly higher for the low-floor apartments than for the high-floor apartments (P < 0.05). The median outdoor concentrations were 5.4, 6.8, and 29.1 microgram/m3, respectively, for the low-floor apartments, yet 4.4, 4.3, and 21.9 microgram/m3, respectively, for the high-floor apartments. Meanwhile, the median indoor concentrations were 6.3, 9.4, and 44.8 microgram/m3, respectively, for the low-floor apartments, yet 5.1, 7.6, and 38.8 microgram/m3, respectively, for the high-floor apartments. These findings indicate that residents of low-floor apartments are exposed to elevated residential levels of mobile source-related VOCs compared to high-floor apartment residents. The indoor concentrations of the target VOCs, except for MTBE, were significantly higher than the outdoor air concentrations for both the low and high floors (P < 0.05). Plus, the outdoor and indoor VOC concentrations were significantly different between the daytime and nighttime data sets for both low- and high-floor apartments, with a P value of less than or close to 0.05.

Air Pollutants↗

PubMed2003

Postprandial hypertriglyceridemia-induced endothelial dysfunction in healthy subjects is independent of lipid oxidation.

BACKGROUND: To analyze the effects of postprandial hypertriglyceridemia with or without antioxidant supplementation-on endothelial function as related to lipid oxidation in healthy young subjects. METHODS AND RESULTS: Ten healthy male subjects (mean age: 26 years) were examined three times in fasting state (10 hours) following a high-fat meal, a low-fat meal, or a high-fat meal with additional antioxidant vitamin E (800 IU), respectively. Serum triglycerides significantly increased 2 and 4 hours after eating the high-fat meal with or without additional vitamin E. Endothelium-dependent, flow-mediated brachial artery vasodilations (FMD; percentage change in diameter) changed from 13.3+/-1.1% to 6.6+/-1.1% (p<0.05), 7.1+/-0.6% (p<0.05), or 13.2+/-0.8% at 2, 4, or 6 hours after eating a high-fat meal. However, there were no changes of FMD observed following either a low-fat meal or a high-fat meal with additional vitamin E. The flow-dependent vasodilation inversely correlated to postprandial hypertriglyceridemia (r=-0.54, p<0.05). Serum malondialdehydes (MDA; lipid oxidation products) did not significantly change following ingestion of any of the 3 types of meal. CONCLUSIONS: This study suggests that postprandial hypertriglyceridemia-induced endothelial dysfunction is not associated with lipid oxidation and that the protective effects of vitamin E on endothelial function may be due to some alternative, as of yet unknown, mechanism.

Adult↗