Biomedical subjects

C U Lee

Publications and source records attributed to C U Lee.

9 recordsLinked to original sources

PubMed2006

Brain activation by visual erotic stimuli in healthy middle aged males.

The objective of the present study was to identify brain centers, whose activity changes are related to erotic visual stimuli in healthy, heterosexual, middle aged males. Ten heterosexual, right-handed males with normal sexual function were entered into the present study (mean age 52 years, range 46-55). All potential subjects were screened over 1 h interview, and were encouraged to fill out questionnaires including the Brief Male Sexual Function Inventory. All subjects with a history of sexual arousal disorder or erectile dysfunction were excluded. We performed functional brain magnetic resonance imaging (fMRI) in male volunteers when an alternatively combined erotic and nonerotic film was played for 14 min and 9 s. The major areas of activation associated with sexual arousal to visual stimuli were occipitotemporal area, anterior cingulate gyrus, insula, orbitofrontal cortex, caudate nucleus. However, hypothalamus and thalamus were not activated. We suggest that the nonactivation of hypothalamus and thalamus in middle aged males may be responsible for the lesser physiological arousal in response to the erotic visual stimuli.

Brain↗

PubMed2001

Interactive 3-dimensional segmentation of MRI data in personal computer environment.

We describe a method of interactive three-dimensional segmentation and visualization for anatomical magnetic resonance imaging (MRI) data in a personal computer environment. The visual feedback necessary during 3-D segmentation was provided by a ray casting algorithm, which was designed to allow users to interactively decide the visualization quality depending on the task-requirement. Structures such as gray matter, white matter, and facial skin from T1-weighted high-resolution MRI data were segmented and later visualized with surface rendering. Personal computers with central processing unit (CPU) speeds of 266, 400, and 700 MHz, were used for the implementation. The 3-D visualization upon each execution of the segmentation operation was achieved in the order of 2 s with a 700 MHz CPU. Our results suggest that 3-D volume segmentation with semi real-time visual feedback could be effectively implemented in a PC environment without the need for dedicated graphics processing hardware.

Adult↗

PubMed2001

Human brain mapping of auditory imagery: event-related functional MRI study.

We used event-related fMRI methodology to investigate human brain activity during auditory imagery. A series of susceptibility-weighted MR images covering the whole brain were acquired to obtain blood oxygenation level-dependent (BOLD) signal changes associated with the imagery event of hearing simple monotone. Group analysis across the 12 right-handed subjects revealed activations in the medial and inferior frontal gyri, precuneus, middle frontal gyri, superior temporal gyri, and anterior cingulate gyri. Bilateral primary and secondary auditory areas in the superior temporal gyri also exhibited the event-related MR signal changes. The proposed method allowed for the analysis of brain areas responsive to the event of auditory imagery while our results suggest that auditory imagery and actual audition share common neural substrates.

Acoustic Stimulation↗

PubMed2001

Identification of antibodies to heat shock proteins 90 kDa and 70 kDa in patients with schizophrenia.

OBJECTIVES: Recent reports of antibodies to heat shock proteins 60kDa (HSP60) and HSP70 suggested that antibodies to the heat shock protein that plays a protective role against environmental stresses in a cell might be related to the pathogenesis of schizophrenia, although the antibody to HSP90 had not yet been identified in patients with schizophrenia. In this study, we tried to elucidate the specific involvement of the autoimmunity to HSPs in the pathogenesis and development of schizophrenia. METHODS: Antibodies to HSP90 and HSP70 in 90 patients with schizophrenia and in 83 normal controls were measured by enzyme-linked immunosorbent assay (ELISA) coupled with the avidin-biotin system. In the patients, the association between antibody levels and clinical variables were sought. In addition, changes in antibody levels after treatment with antipsychotic medication were investigated. RESULTS: Eighteen (20.0%) of the 90 patients showed 'high' levels of antibody to HSP90 above a cutoff value, and 28 (31.1%) of those showed 'high' antibody levels to HSP70. On the other hand, only four (4.8%) of the normal controls showed 'high' HSP90 antibody levels, and one (1.2%) of these showed 'high' antibody level to HSP70. The distribution of elevated HSP90 antibody was significantly associated with that of elevated HSP70 antibody in the patients with schizophrenia. The patients with 'high' levels of antibody to HSP70 showed higher initial Brief Psychiatric Rating Scale (BPRS) scores and showed greater clinical improvement than those with 'low' levels, while the patients with 'high' levels of antibody to HSP90 did not. The frequency of patients with high levels of antibody to HSP70 was decreased significantly after 6 weeks of antipsychotic treatment, while the frequency of patients with high levels of antibody to HSP90 was not. CONCLUSIONS: Our results presented the presence of abnormal immune reactivity involving antibody to HSP90 and antibody to HSP70 in a subset of patients with schizophrenia. Differential patterns of distribution, of the association with clinical symptom severity, and of the changes of levels with treatment suggested the possibility that these two antibodies might be involved specifically in the pathogenesis of schizophrenia.

Adolescent↗

PubMed2000

Specific binding of recombinant Listeria monocytogenes p60 protein to Caco-2 cells.

The Listeria monocytogenes p60 is a major extracellular protein, which is believed to be involved in the invasion of these bacteria into their host cells. So far the mechanism by which p60 participates in the internalization or penetration of L. monocytogenes is still veiled. To determine the possibility of a direct interaction of p60 with the host cell surface, the iap gene was recombinantly expressed in Escherichia coli and used for binding studies with the enterocyte-like Caco-2 cells. Fluorescence activated flow cytometry and confocal laser scanning microscopy revealed a cell membrane specific staining with p60, which implications in Listeria virulence are discussed.

Bacterial Proteins↗

PubMed1999

Evaluation of urinary cadmium and lead as markers of background exposure of middle-aged women in Korea: dietary intake as an influential factor.

The study was conducted to examine the validity of urinary cadmium (Cd) and lead (Pb) in comparison with the metals in blood as a biological marker of non-occupational exposure of general populations. Participants in four survey sites in Korea (107 non-smoking Korean women aged 30-49 years) offered peripheral blood, morning spot urine, and 24-h total food duplicate samples. Analysis of Cd and Pb was accomplished by graphite furnace atomic absorption spectrophotometry. The analyse levels were evaluated on an individual basis (n = 107) and also on a survey site basis, i.e. in terms of geometric means for the groups in the survey sites (n = 4). Cd in urine (as observed, or after correction for creatinine concentration or a specific gravity) correlated with Cd in blood on an individual as well as survey site basis, and tended to correlate with Cd in food duplicates on the survey site basis. Correlation of Pb in urine with Pb in blood was weaker than that of Cd in urine with Cd in blood both on the individual and survey site basis. Pb in urine correlated with Pb in food duplicates either weakly or even negatively when examined on a survey site basis. It was concluded that Cd in urine can be most probably employed as a biological marker of environmental Cd exposure of general population, whereas less support was obtained for Pb in urine as an exposure marker.

Adult↗

PubMed1998

Evaluation of urinary cadmium and lead as markers of background exposure of middle-aged women in Korea.

OBJECTIVE: The present study was initiated to investigate the validity of cadmium (Cd) and lead (Pb) in urine in comparison with the metals in blood as a biological marker of nonoccupational exposure of general populations to these metals as environmental pollutants. DESIGN: Peripheral blood samples, morning spot-urine samples, and 24-h total food duplicate samples were collected from 107 nonsmoking women (aged 30-59 years) in four urban and rural survey sites in Korea. METHODS: Portions of the samples were digested by heating in the presence of mineral acids, and the digests were analyzed for Cd and Pb by graphite furnace atomic absorption spectrophotometry. The metal concentrations in urine were adjusted for creatinine concentration and a specific gravity of 1.016. The analyte levels were evaluated on an individual basis (n = 107) and also on a group basis, i.e., in terms of geometric means for the survey sites (n = 4). RESULTS: Cd in urine correlated with Cd in blood on an individual as well as survey-site basis and tended to correlate with Cd in food duplicates on a group basis. The correlation of Pb in urine with Pb in blood was weaker than that of Cd in urine with Cd in blood when evaluated on an individual and survey-site basis. Pb in urine correlated with Pb in food duplicates either weakly or even negatively when examined on a survey-site basis. CONCLUSIONS: Cd in urine proved to be valid as a biological marker of environmental exposure of general populations, whereas less support was obtained for Pb in urine as an exposure marker.

Adult↗

PubMed1996

Hepatitis B and C virus, Clonorchis sinensis for the risk of liver cancer: a case-control study in Pusan, Korea.

BACKGROUND: Liver cancer mortality in Korea is the highest in the world. Hepatitis B and C viruses (HBV, HCV) are known to be the major risk factors of hepatocellular carcinoma (HCC). Cholangiocarcinoma (CLG) accounts for more than 20% of liver cancer in the Pusan area. In Korea, the different roles of known risk factors in the development of HCC or CLG have not been adequately evaluated. METHODS: Case-control studies involved 203 incident HCC cases, 406 controls matched to the HCC cases for age (+/- 4 years) and sex, and 41 CLG cases (the HCC controls were used). They were carried out from August 1990 to August 1993. RESULTS: Relative risk (RR) of HBsAg (87.4; 95% confidence interval [CI]: 22.2-344.3) and RR of anti-HCV positivity (30.3; 95% CI: 6.1-150.6) were significant for the risk of HCC after adjustment for potentially confounding factors. In contrast, RR of Clonorchis sinensis in stool (2.7; 95% CI: 1.1-6.3) and RR of heavy drinking (4.6; 95% CI: 1.4-15.2) were significant for the risk of CLG. Transfusion history, acupuncture history, and cigarette smoking were not associated with the risk of HCC or CLG. CONCLUSIONS: Strong evidence indicated that both HBV and HCV infection were independent risk factors for HCC. In contrast, C. sinensis in stools and heavy drinking were associated with the risk of CLG in Korea.

Adult↗

PubMed1995

Dietary intake of cadmium and lead among the general population in Korea.

This survey was conducted in Seoul, Pusan, Chunan, and Haman in Korea to clarify cadmium and lead burden in the general Korean populations in terms of dietary intake of cadmium and lead and the concentrations of the two metals in blood. People who participated in the study were 141 healthy nonsmoking women aged 21-56 years. Determination of cadmium and lead in 24-hr food duplicates and blood samples was carried out by graphite furnace atomic absorption spectrophotometry. The geometric means for the four sites in combination were 21.2 micrograms/day for dietary cadmium, 20.5 micrograms/day for dietary lead, 1.27 ng/ml for blood cadmium, and 44.3 ng/ml for blood lead. Cadmium intake from boiled rice accounted for 23% of total daily cadmium intake. The counterpart value for lead intake from boiled rice was 12%. Blood cadmium levels and dietary cadmium intake were lower and blood lead level and dietary lead intake were higher in Korean women than in Japanese women. The values for dietary cadmium are similar to, and the values for dietary lead are somewhat lower than, the levels reported from Europe and the United States. Dietary intake was the main source of cadmium exposure, whereas lead exposure was from both ambient air and foods in the Korean population.

Adult↗