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Biomedical subjects

J Y Lee

Publications and source records attributed to J Y Lee.

At least 19 recordsLinked to original sources
PubMed2007

Self-enhancing bias in personality, subjective happiness, and perception of life-events: a replication in a Korean aged sample.

Interrelations among self-enhancing bias in personality, subjective happiness, and perception of life-events have been examined. Elderly people with higher subjective happiness, compared to those with lower happiness, were predicted to have higher self-enhancing bias in personality, and perceive negative life-events less negatively. One hundred and forty elderly Korean citizens were assessed as to their tendency to self-enhance and to perceive positive and negative life-events. A correlation of 0.26 was found between subjective happiness and self-enhancing bias. Contrary to our prediction, those with higher subjective happiness perceived positive life-events more positively than those with lower subjective happiness, whereas there was no difference between the two groups in the perception of negative life-events.

Aged↗
PubMed2006

Mobilization of arsenic in groundwater of Bangladesh: evidence from an incubation study.

The extensive extraction of arsenic (As)-contaminated groundwaters for drinking, household and agricultural purposes represents a serious health concern in many districts of Bangladesh. This laboratory-based incubation study investigated the sources and mechanisms of As mobilization in these groundwaters. Several incubation studies were carried out using sediments collected from the Bangladesh aquifer that were supplemented, or not, with different nutrients, followed by an analysis of the sediment suspensions for pH, ORP (oxidation-reduction potential), EC (electrical conductivity) and As and Fe(II) concentrations. In the substrate-amended sediment suspensions incubated under anaerobic environment, there was a mobilization of As (maximum: 50-67 microg/l) and Fe(II) (maximum: 182 microg/l), while the ORP value decreased immediately and drastically (as much as -468 mV to -560 mV) within 5-6 days. In the sediment suspensions incubated under control and aerobic conditions, no significant As mobilization occurred. The simultaneous mobilization of As and Fe(II) from sediments is a strong indication that their mobilization resulted from the reduction of Fe oxyhydroxide by the enhanced activity of indigenous bacteria present in the sediments; this phenomenon also provides insights on the mobilization mechanism of As in groundwater. The concentrations of As in the sediments used in the incubation studies were strongly linked to the gradients of redox potential development that was stimulated by the quantity of organic nutrient (glucose) used. The penetration of surface-derived organic matter into the shallow aquifer may stimulate the activity of microbial communities, thereby leading to a reduction of iron oxyhydroxide and As release.

Arsenic↗
PubMed2006

Impact of diagnostic laparoscopy on the management of chronic pelvic pain.

BACKGROUND: Diagnostic laparoscopy is a useful tool, especially when there is no definite anatomical abnormality visible on imaging modalities. We assess the role and clinical impact of diagnostic laparoscopy in the management of women with chronic pelvic pain. METHODS: Clinical data of 3,068 cases of diagnostic laparoscopy performed for chronic pelvic pain from June 1994 to August 2005 were analyzed. We compared the diagnoses after diagnostic laparoscopy and those after pelvic examination and imaging modalities such as ultrasound or computed tomography (CT), and we then checked the final pathologic diagnoses after operation. RESULTS: Pelvic endometriosis was the most common (60.2%) laparoscopic finding in patients with chronic pelvic pain in this study, followed by normal pelvic findings (21.2%) and pelvic congestion (13.0%). Diagnostic laparoscopy had an influence on correcting previous plans based on imaging modalities in 42.7% of patients such as discarding unnecessary procedures or introducing new diagnostic or therapeutic plans. There were 3 cases of major complications requiring immediate correction. CONCLUSIONS: Diagnostic laparoscopy is a useful diagnostic tool for of women with chronic pelvic pain and can be used as a guideline for individualized treatment.

Adolescent↗
PubMed2006

Association of aortic plaque with intracranial atherosclerosis in patients with stroke.

OBJECTIVE: To determine whether there is a relationship between aortic plaques and intracranial (IC) atherosclerosis. METHODS: We reviewed 922 patients with stroke who had both transesophageal echocardiography and cerebral angiography. The plaques of these patients were classified as either complex aortic plaques (CAP), which protruded > or =4 mm or were present as mobile lesions in the proximal aorta, or simple aortic plaques (SAP), which were <4 mm or present in the descending aorta. Cerebral artery atherosclerosis was classified as either an IC or extracranial (EC) atherosclerosis. RESULTS: Among the 922 patients, we found aortic plaques in 237 patients (26%). There were 111 (47%) patients of SAP, 74 (31%) patients with CAP, and 52 (22%) patients that had both SAP and CAP. Angiography showed IC or EC atherosclerosis in 511 patients (55%). The presence of aortic plaques was significantly associated with IC or EC atherosclerosis. The significance appeared to be due to the strong association between the presence of SAP and IC atherosclerosis (51% SAP vs 35% no plaques; odds ratio = 1.94, 95% CI: 1.17 to 3.21). In the multiple logistic regression analysis, SAP were independent predictors of IC atherosclerosis CONCLUSIONS: The presence of simple aortic plaques may be a marker of advanced vascular disease. Detection of simple aortic plaques during transesophageal echocardiography may have clinical implications because patients with these plaques frequently had concomitant intracranial atherosclerosis, a risk factor for stroke.

Aged↗
PubMed2006

Acceleration of cerebral ventricular expansion in the Cardiovascular Health Study.

Interactions between prevalent late-life medical conditions and expansion of the cerebral ventricles are not well understood. Thirty elderly subjects received three magnetic resonance (MR) scans each, in 1997-1999, 2002-2004, and 2003-2005. A linear expansion model of MR-measured lateral ventricle volume was estimated for each subject by fitting a line to a plot of their 1997-1999 and 2002-2004 volumes as a function of time. Acceleration in ventricular expansion was defined as the deviation between the 2003-2005 volumes measured from MR and the 2003-2005 volumes predicted by the linear expansion model. Ventricular acceleration was analyzed in a multivariate model with age, race, history of heart disease, diabetes, and hypertension as fixed effects. Ventricular acceleration was significantly higher in non-whites, diabetics, and those without heart disease (p<0.05). Ventricular acceleration was higher in subjects with a history of hypertension, but the difference was not statistically significant (p=0.08). Acceleration of ventricular expansion in the elderly may be related to demographic and cardiovascular factors.

Aged↗
PubMed2006

Mutational analysis of the hCDC4 gene in gastric carcinomas.

hCDC4, a ubiquitin ligase, plays a role in the control of cell cycle and chromosome stability. The hCDC4 gene is considered a tumour suppressor gene and is mutated in several human neoplasias, including colorectal and endometrial tumours. Data on the hCDC4 mutation in gastric cancer is, however, lacking. This study explored the possibility that hCDC4 mutation is involved in the development of gastric cancer. The hCDC4 gene in 162 gastric adenocarcinoma tissues was analysed for somatic mutations using a polymerase chain reaction-single strand conformation polymorphism assay. Overall, six hCDC4 mutations were found (3.7%), comprising four missense, one frameshift deletion and one nonsense mutation(s). It is notable that the hCDC4 mutations were found in early as well as in advanced gastric carcinomas. These data indicate that hCDC4 mutation occasionally occurs in gastric carcinomas and suggest that it might play a role in the development of some gastric carcinomas.

Aged↗
PubMed2006

Expressional analysis of anti-apoptotic phospho-BAD protein and mutational analysis of pro-apoptotic BAD gene in hepatocellular carcinomas.

BACKGROUND: It has become clear that, together with proliferation, deregulation of apoptosis plays a pivotal role in tumourigenesis. BAD is a pro-apoptotic Bcl-2 family protein and regulates the intrinsic apoptosis pathway. Phosphorylation of BAD inhibits the apoptosis function of BAD. AIMS: To investigate whether alteration of the phospho-BAD protein and somatic mutation of BAD gene are characteristics of human hepatocellular carcinoma. PATIENTS AND METHODS: We analysed the expression of phospho-BAD in 20 hepatocellular carcinomas by immunohistochemistry. Also, we analysed the BAD gene for the detection of somatic mutations by a single-strand conformation polymorphism assay in 69 hepatocellular carcinomas. RESULTS: Phospho-BAD expression in the non-tumour hepatocytes was seen in all of the hepatocellular carcinomas, while the expression in the cancer cells was observed in 15% (3 of the 20) of the hepatocellular carcinomas. There was no somatic mutation of BAD Bcl-2 homology 3 (BH3) domain in the 69 hepatocellular carcinomas. CONCLUSIONS: The data showed that loss of phospho-BAD expression, but not BAD gene mutation, is a feature of hepatocellular carcinomas. The decreased expression of phospho-BAD in the hepatocellular carcinoma cells compared to the non-tumour hepatocytes suggests that loss of phospho-BAD expression may play a role in hepatocellular tumourigenesis.

BH3 Interacting Domain Death Agonist Protein↗
PubMed2006

A novel phospholipid derivative of indomethacin, DP-155 [mixture of 1-steroyl and 1-palmitoyl-2-{6-[1-(p-chlorobenzoyl)-5-methoxy-2-methyl-3-indolyl acetamido]hexanoyl}-sn-glycero-3-phosophatidyl [corrected] choline], shows superior safety and similar efficacy in reducing brain amyloid beta in an Alzheimer's disease model.

Indomethacin has been suggested for the treatment of Alzheimer's disease (AD), but its use is limited by gastrointestinal and renal toxicity. To overcome this limitation, D-Pharm Ltd. (Rehovot, Israel) developed DP-155 (mixture of 1-steroyl and 1-palmitoyl-2-{6-[1-(p-chlorobenzoyl)-5-methoxy-2-methyl-3-indolyl acetamido] hexanoyl}-Sn-glycero-3-phosophatidyl [corrected] choline), a lecithin derivative of indomethacin. Safety was tested by daily oral administration of DP-155 or indomethacin to rats in a dose range of 0.007 to 0.28 mmol/kg. The prevalence of gastrointestinal ulceration was significantly lower (10-fold) for DP-155 than for indomethacin, and the ulcerations were delayed. Signs of renal toxicity, namely reduced urine output and increased urine N-acetyl glycosaminidase to creatinine ratio, were 5-fold lower for DP-155. Indomethacin, but not an equimolar dose of DP-155, reduced urine bicyclo-prostaglandin E(2). An equimolar oral dose of DP-155 or indomethacin, administered every 4 h for 3 days, was equally efficacious in reducing the levels of Abeta42 in the brains of Tg2576 mice. Indomethacin was the principal metabolite of DP-155 in the serum. After DP-155 oral administration, indomethacin's half-life in the serum and the brain was 22 and 93 h, respectively, compared with 10 and 24 h following indomethacin oral administration. The brain to serum ratio was 3.5 times higher for DP-155 than indomethacin. This finding explains the efficacy of DP-155 in reducing Abeta42 brain levels, despite the low systemic blood concentrations of indomethacin derived from DP-155. In conclusion, compared with indomethacin, DP-155 has significantly lower toxicity in the gut and kidney while maintaining similar efficacy to indomethacin in lowering Abeta42 in the brains of Tg2576 mice. This superior safety profile highlights DP-155's potential as an improved indomethacin-based therapy for AD.

Alzheimer Disease↗
PubMed2006

Comparison of two commercial interferon-gamma assays for diagnosing Mycobacterium tuberculosis infection.

The clinical usefulness of ex vivo interferon-gamma assays may largely depend on the assay format and epidemiological status of tuberculosis (TB) in the region studied. From July 2004 to June 2005 a prospective comparison study was undertaken at a tertiary referral hospital in South Korea. The results of tuberculin skin tests (TST) and the commercially available QuantiFERON-TB Gold (QFT-G) and T SPOT-TB (SPOT) assays were compared in an intermediate TB-burden country. Of the 224 participants studied, results from all three tests (TST, QFT-G, and SPOT) were available in 218; 87 with active TB and 131 at a low risk for TB. Using 10 mm as a cut-off for TST, SPOT sensitivity (96.6%) was significantly higher than that seen for TST (66.7%) and QFT-G (70.1%). QFT-G showed superior specificity over TST (91.6 versus 78.6%). Although the specificity of QFT-G was higher than that of SPOT (91.6 versus 84.7%), the difference was not statistically significant. Whilst some differences were found in the performance of the two commercialised interferon-gamma assays, they seemed to be superior in their detection of Mycobacterium tuberculosis infection compared with tuberculin skin tests. The most appropriate choice of interferon-gamma assay to use may depend on the clinical setting.

Adolescent↗
PubMed2006

The JAK2 V617F mutation in de novo acute myelogenous leukemias.

A missense somatic mutation in JAK2 gene (JAK2 V617F) has recently been reported in chronic myeloproliferative disorders, including polycythemia vera, essential thrombocythemia and myelofibrosis with myeloid metaplasia, strongly suggesting its role in the pathogenesis of myeloid disorders. As activation of JAK2 signaling is occurred in other malignancies as well, we have analysed 558 tissues from common human cancers, including colon, breast and lung carcinomas, and 143 acute adulthood leukemias by polymerase chain reaction -- single strand conformation polymorphism analysis. We found three JAK2 mutations in the 113 acute myelogenous leukemias (AMLs) (2.7%), but none in other cancers. The mutations consisted of two V617F mutations and one K607N mutation. None of the AML patients with the JAK2 V617F mutation had a history of previous hematologic disorders. This is the first report on the JAK2 gene mutation in AML, and the data indicated that the JAK2 gene mutation may not only contribute to the development of chronic myeloid disorders, but also to some AMLs.

Adult↗
PubMed2006

Merlin facilitates ubiquitination and degradation of transactivation-responsive RNA-binding protein.

The Nf2 tumor suppressor codes for merlin, a protein whose function is largely unknown. We have previously demonstrated a novel interaction between merlin and TRBP, which inhibits the oncogenic activity of TRBP. In spite of the significance of their functional interaction, its molecular mechanism still remains to be elucidated. In this report, we investigated how merlin inhibits the oncogenic activity of TRBP in association with cell growth conditions. In the human embryonic kidney 293 cell line, the level of endogenous merlin increased, whereas that of endogenous TRBP significantly decreased along with the increase in cell confluence. We demonstrated that the carboxyl-terminal region of TRBP was responsible for this phenomenon using stable cell lines expressing deletion mutants of TRBP. The overexpression of merlin decreased the protein level of TRBP, and the ubiquitin-like subdomain of merlin's FERM domain was important for this activity. We also demonstrated that TRBP is ubiquitinylated and the ubiquitinylated forms of TRBP are accumulated by ectopically expressed merlin or cell confluence in the presence of MG132, a proteasome inhibitor. Furthermore, we showed that the regulation of TRBP in response to cell confluence was abolished upon knockdown of merlin expression by specific small interfering RNA. Finally, we showed that ectopically expressed merlin restored cell-cell contact inhibition in cells stably expressing TRBP but not in TRBPDeltac. These results suggest that merlin is involved in the regulation of TRBP protein level by facilitating its ubiquitination in response to such cues as cell-cell contacts.

Animals↗
PubMed2006

CT colonography in a Korean population with a high residue diet: comparison between wet and dry preparations.

AIM: To compare wet and dry preparation methods for computed tomography colonography (CTC) in terms of preparation quality, interpretation time, and diagnostic performance for polyp detection in a population with a high residue diet. MATERIALS AND METHODS: Eighty-six patients were divided into two groups. Group 1 (n=24) received a wet preparation of 4l polyethylene glycol (PEG) solution, and group 2 (n=62) received a dry preparation of phosphor-soda. Abnormal findings, including polyps, and the time required to interpret the CTC images in both groups were documented by a radiologist. CTC findings were compared to those of colonoscopy as a reference standard. Two radiologists evaluated the quality of CTC with regard to residual fluid, faeces, and colonic distension using a four-point scale in consensus. Statistical differences for residual fluid, faeces, distensibility on CTC, and interpretation time between the two groups were analysed. The diagnostic performance of CTC in both groups was also compared. RESULTS: One-hundred and ninety polyps in 70 patients were identified using colonoscopy. Regarding the quality of images produced the wet preparation was significantly better than the dry preparation (p<0.05). The average interpretation time was significantly shorter for the wet group (11.7 min) than the dry group (16.4 min) (p<0.05). For per-patient analysis, the positive predictive value (PPV) was significantly better for the wet (100%) than the dry group (79.6%; p=0.025). Sensitivities and PPV for >or=10 mm polyps were comparable between two groups (p>0.05). CONCLUSION: In a population with a high-residue diet, CTC with wet preparation can be interpreted in a time-efficient manner and is comparable with CTC with dry preparation.

Adenomatous Polyposis Coli↗
PubMed2006

AtBAG6, a novel calmodulin-binding protein, induces programmed cell death in yeast and plants.

Calmodulin (CaM) influences many cellular processes by interacting with various proteins. Here, we isolated AtBAG6, an Arabidopsis CaM-binding protein that contains a central BCL-2-associated athanogene (BAG) domain. In yeast and plants, overexpression of AtBAG6 induced cell death phenotypes consistent with programmed cell death (PCD). Recombinant AtBAG6 had higher affinity for CaM in the absence of free Ca2 + than in its presence. An IQ motif (IQXXXRGXXXR, where X denotes any amino-acid) was required for Ca2 +-independent CaM complex formation and single amino-acid changes within this motif abrogated both AtBAG6-activated CaM-binding and cell death in yeast and plants. A 134-amino-acid stretch, encompassing both the IQ motif and BAG domain, was sufficient to induce cell death. Agents generating oxygen radicals, which are known to be involved in plant PCD, specifically induced the AtBAG6 transcript. Collectively, these results suggest that AtBAG6 is a stress-upregulated CaM-binding protein involved in plant PCD.

Amino Acid Motifs↗
PubMed2006

Randomized comparison of ultrasound surveillance and clinical monitoring on arteriovenous graft outcomes.

Arteriovenous graft thrombosis is a frequent event in hemodialysis patients, and usually occurs in grafts with significant underlying stenosis. Regular surveillance for graft stenosis, with pre-emptive angioplasty of significant lesions, may improve graft outcomes. This prospective, randomized, clinical trial allocated 126 hemodialysis patients with grafts to either clinical monitoring alone (control group) or to regular ultrasound surveillance for graft stenosis every 4 months in addition to clinical monitoring (ultrasound group). The two randomized groups were closely matched with respect to demographic, clinical, and graft characteristics, with the exception of a lower frequency of diabetes in the ultrasound group. The primary outcome was graft survival, and the secondary outcome was thrombosis-free graft survival. The frequency of pre-emptive graft angioplasty was 64% higher in the ultrasound group than in the control group (1.05 vs 0.64 events per patient-year, P<0.001), whereas the frequency of thrombosis was not different (0.67 vs 0.78 per patient-year, P=0.37). The median time to permanent graft failure was similar between the two groups (38 vs 37 months, P=0.93). Likewise, the median time to graft thrombosis or failure did not differ (22 vs 25 months, P=0.33). There was no significant association between diabetes and time to graft failure (P=0.93) or time to graft thrombosis or failure (P=0.88). In conclusion, the addition of regular ultrasound surveillance for graft stenosis to clinical monitoring increases the frequency of pre-emptive angioplasty, but may not decrease the likelihood of graft failure or thrombosis.

Aged↗
PubMed2006

Hepatic intra-arterial injection of 3-bromopyruvate in rabbit VX2 tumor.

PURPOSE: To evaluate the antitumoral effects of an intra-arterial injection of 3-bromopyruvate (3-BrPA) on liver VX2 tumor in rabbits. MATERIAL AND METHODS: Twenty rabbits with surgically implanted liver VX2 tumors were used. The rabbits were divided into three groups: a control, a saline, and a 3-BrPA group. Four rabbits were not treated at all, and they served as the control group. The saline group (n = 6) received only intra-arterial saline injection. The 3-BrPA group (n = 10) received an intra-arterial injection of 3-bromopyruvate through the hepatic artery. The delivered amounts of 3-bromopyruvate were as follows: 25 ml of 0.5 mM in six rabbits, 25 ml of 1.0 mM in two rabbits, and 25 ml of 2.0 mM in two rabbits. Four days after intra-arterial injection, the rabbits were sacrificed and histopathologic analysis of the explanted livers was performed with comparison of the tumor necrosis ratio (a percentage of the necrotic area versus the entire tumorous area) in each group. RESULTS: The mean tumor necrosis ratio was 12.5+/-4.2%, 44.8+/-24.7%, and 49.4+/-14.3% in the control, saline, and 3-BrPA groups, respectively. Between the control and the saline group, and between the control and the 3-BrPA group the mean tumor necrosis ratio appeared to be significantly different (P<0.05). However, there was no statistical difference in the mean tumor necrosis ratio between the saline and the 3-BrPA group (P = 0.416). CONCLUSION: A single session of intra-arterial injection of 3-BrPA showed no better results in terms of tumor necrosis than that of saline injection in a rabbit VX2 tumor model.

Animals↗
PubMed2006

The dermal stem cell factor and c-kit are overexpressed in melasma.

BACKGROUND: The pathogenesis of melasma has not yet been clearly demonstrated. We tried to determine whether the stem cell factor (SCF) and its receptor c-kit are involved in the mechanism of hyperpigmentation of melasma because this factor is highly implicated in the stimulation of melanocyte function in vitro and in vivo. OBJECTIVES: The present study was conducted to investigate the expression of SCF and c-kit on the lesions of melasma compared with nonlesional skin. PATIENTS/METHODS: Skin samples were obtained from lesional and nonlesional facial skin of 60 Korean women with melasma. Immunohistochemistry and reverse transcriptase-polymerase chain reaction (RT-PCR) analysis was performed to determine the expression of SCF and c-kit in melasma. RESULTS: The expression of SCF was significantly increased at the lesional dermis compared with nonlesional dermis. However, there was no significant difference in the expression of SCF in lesional and nonlesional epidermis. The expression of c-kit was significantly increased at lesional epidermis compared with nonlesional skin. RT-PCR of SCF and c-kit mRNAs demonstrated increased expression of both types of transcripts in the lesional skin compared with nonlesional skin. CONCLUSIONS: These results suggest that the increased expression of SCF in the dermis and of c-kit in the epidermis play an important role in the mechanism of hyperpigmentation in melasma.

Adult↗
PubMed2006

Investigation of the corticotropin-releasing hormone-proopiomelanocortin axis in various skin tumours.

BACKGROUND: Various types of external stress cause the skin and central neuroendocrine system to express corticotropin-releasing hormone (CRH)-proopiomelanocortin (POMC) axis-related hormones. However, the precise role of the CRH-POMC axis-related hormones in various skin tumours is unclear. OBJECTIVES: This study examined expression patterns of the CRH-POMC axis-related hormones in skin tumours. METHODS: The production of CRH, adrenocorticotropic hormone (ACTH) and alpha-melanocyte-stimulating hormone (alpha-MSH) in various tumour cell lines including HaCaT and primary keratinocytes was examined using an enzyme-linked immunosorbent assay. Immunohistochemical analysis of the skin tumours was also performed. RESULTS: CRH, ACTH and alpha-MSH were strongly expressed in malignant skin tumour cell lines such as G-361 and DX-3 (both malignant melanoma, MM). However, normal and haematological malignancy cell lines did not express the CRH-POMC axis-related hormones. Immunohistochemical analysis of the skin tumours showed that MM (80%), squamous cell carcinoma (SCC, 70%) and basal cell carcinoma (BCC, 10%) had strong immunoreactivity (++/+++) for CRH. Strong ACTH and alpha-MSH expression was observed in MM (70% and 50%, respectively), SCC (80% and 60%, respectively) and BCC (70% and 50%, respectively). CONCLUSIONS: We report that an increase in the level of the CRH-POMC axis-related hormones is associated with malignant skin tumours such as MM. These results highlight the importance of the CRH-POMC axis-related hormones in the malignant tendency of skin tumours.

Adrenocorticotropic Hormone↗