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Biomedical subjects

E K Kim

Publications and source records attributed to E K Kim.

At least 19 recordsLinked to original sources
PubMed2003

Effects of icariin on cGMP-specific PDE5 and cAMP-specific PDE4 activities.

AIM: To clarify the mechanism of the therapeutic action of icariin on erectile dysfunction (ED). METHODS: PDE5 was isolated from the human platelet and PDE4 from the rat liver tissue using the FPLC system (Pharmacia, Milton Keynes, UK) and the Mono Q column. The inhibitory effects of icariin on PDE5 and PDE4 activities were investigated by the two-step radioisotope procedure with [(3)H]-cGMP/[(3)H]-cAMP. Papaverine served as the control drug. RESULTS: Icariin and papaverine showed dose-dependent inhibitory effects on PDE5 and PDE4 activities. The IC(50) of Icariin and papaverine on PDE5 were 0.432 micromol/L and 0.680 micromol/L, respectively and those on PDE4, 73.50 micromol/L and 3.07 micromol/L, respectively. The potencies of selectivity of icariin and papaverine on PDE5 (PDE4/PDE5 of IC(50)) were 167.67 times and 4.54 times, respectively. CONCLUSION: Icariin is a cGMP-specific PDE5 inhibitor that may be developed into an oral effective agent for the treatment of ED.

3',5'-Cyclic-AMP Phosphodiesterases↗
PubMed2002

Occurrence of zearalenone in Korean barley and corn foods.

The presence of zearalenone (ZEN) in Korean foods such as barley, barley-based foods, corn, corn-based foods, fruits and vegetables was investigated by direct competitive enzyme-linked immunosorbent assay (dcELISA) and the liquid chromatography (LC) method. A total of 164 samples was collected from Seoul, Korea, in 1998 and 1999 including 30 barley, 32 barley-based foods, 18 corn, 47 corn-based foods, 19 dried red pepper, nine dried jujube, and nine dried persimmon. Average recoveries of ZEN from barley and corn by dcELISA were 138 and 145%, and by LC were 91 and 83% respectively at spiking levels of 5-500 ngg(-1). The detection limit for ZEN was 3 ng g(-1) by dcELISA and 4 ngg(-1) by LC. From 164 samples analysed, ZEN was found by dcELISA in 35 samples (21%) with a mean level of 30 ng g(-1). Barley-based foods had the highest incidence of ZEN (38%) followed by barley (33%), corn-based foods (26%) and corn (22%). No ZEN was detected in any red pepper, jujube or persimmon samples. A high degree of correlation (r2 = 0.86) was observed between the 35 positive samples detected by dcELISA and 31 samples by LC.

Chromatography, Liquid↗
PubMed2002

Natural co-occurrence of aflatoxin B1, fumonisin B1 and ochratoxin A in barley and corn foods from Korea.

A survey for aflatoxin B1 (AFB1), fumonisin B1 and ochratoxin A (OTA) was conducted on 127 samples that included 30 food-grade barley, 32 barley foods, 18 food-grade corn and 47 corn foods, randomly collected during 1998-99 in Seoul, Korea. The presence of mycotoxins was analysed by direct competitive enzyme-linked immunosorbent assay (ELISA), and most of the positive samples from ELISA were confirmed using high-performance liquid chromatography (HPLC). Recoveries of AFB1 and OTA spiked at 10 ng g(-1) and FB1 spiked at 50 ng g(-1) were 106, 87 and 105% by ELISA, whereas those by HPLC were 80, 79 and 84%, respectively. Detection limits by ELISA for AFB1, FB1 and OTA were 1, 5 and 5 ng g(-1), and those by HPLC were 0.6, 35 and 1 ng g(-1). Naturally occurring AFB1, FB1 and OTA were found in 4/32 (12%), 2/32(6%) and 4/32 (12%) samples of barley foods with an average of 26, 16 and 9 ng g(-1), respectively. AFB1 and FB1 in corn foods were detected in 4/47 (8%) and 9/47 (19%) samples with the average being 20 and 74 ng g(-1), while no OTA was found in any corn foods samples. No AFB1, FB1 or OTA was detected in any of food-grade barley and corn samples. This is the first report on the natural co-occurrence of AFB1 and FB1 in barley and corn foods as well as on surveillance of OTA in Korea.

Aflatoxin B1↗
PubMed2002

Enhanced expression of transglutaminase 2 in anterior polar cataracts and its induction by TGF-beta in vitro.

BACKGROUND/AIMS: Transglutaminase activity has long been implicated in the cataract formation. However, the precise mechanism of how it is produced and involved in this process remains unclear. Here the authors sought to examine whether transglutaminase 2 (TGase 2) is expressed in lens epithelial cells from patients with anterior polar cataracts, to determine whether TGase 2 expression is induced by transforming growth factor (TGF-beta) in cultured lens epithelial cells, and to determine whether TGase 2 participates in the crosslinking of fibronectin in lens epithelial cells in vitro. METHODS: Lens epithelial cells from anterior polar cataracts, nuclear cataracts, and non-cataractous clear lenses were examined for the expression of TGase 2 using reverse transcription-polymerase chain reaction, western blot analysis, and immunohistochemical analysis. The modulation of extracellular TGase 2 activity by TGF-beta was measured by the formation of fibronectin polymers and the incorporation of fluorescein cadaverine into extracellular matrix proteins. The effect of TGase 2 overexpression was analysed by immunofluorescence staining and western blot analysis of human lens epithelial (HLE) B-3 cells transiently transfected with TGase 2 gene. RESULTS: The expression of TGase 2 mRNA and its protein was markedly enhanced in lens epithelial cells from patients with anterior polar cataracts. Treatment of HLE B-3 cells with TGF-beta caused an increase in TGase 2 protein, its extracellular activity, and the crosslinking of fibronectin. Transient transfection of HLE B-3 cells with the TGase 2 gene led to the increased production of fibronectin monomers and polymers. CONCLUSIONS: This study shows that TGase 2 is overexpressed in lens epithelial cells from anterior polar cataracts and that TGF-beta may be a causative factor in the induction of TGase 2. The enhanced expression of TGase 2 might cause the accumulation and crosslinking of the extracellular matrix proteins and might play a part in anterior polar cataract development.

Aged↗
PubMed2001

Synthesis, topoisomerase I inhibition and antitumor cytotoxicity of 2,2':6',2"-, 2,2':6',3"- and 2,2':6',4"-terpyridine derivatives.

For the development of new anticancer agents, 2,2':6',2"-, 2,2':6',3"- and 2,2':6',4"-terpyridine derivatives were designed and evaluated for their topoisomerase I inhibitory activity and antitumor cytotoxicity. Structure-activity relationship studies indicated that 2,2':6',2"-terpyridine derivatives were highly cytotoxic toward several human tumor cell lines, whereas 2,2':6',3"- and 2,2':6',4"-terpyridine derivatives were potent topoisomerase I inhibitors.

Antineoplastic Agents↗
PubMed2001

Inhibitory effect of ursolic acid purified from Origanum majorana L on the acetylcholinesterase.

We screened 139 herbal spices in search of the acetylcholinesterase (AChE) inhibitor from natural resources. AChE inhibitors, which enhance cholinergic transmission by reducing the enzymatic degradation of acetylcholine, are the only source of compound currently approved for the treatment of Alzheimer's Disease (AD). Among these herbs, edible plants and spices, the ethanol extract from Origanum majorana L. showed the highest inhibitory effect on AChE in vitro. By sequential fractionation of Origanum majorana L. the active component was finally identified as ursolic acid (3 beta-Hydroxyurs-12-en-28-oic acid). The ursolic acid of Origanum majorana L. inhibited AChE activity in a dose-dependent and competitive/non-competitive type. The Ki value (representing the affinity of the enzyme and inhibitor) of Origanum majorana L. ursolic acid was 6 pM, and that of tacrine was 0.4 nM. The concentration required for 50% enzyme inhibition of the active component (IC50 value) was 7.5 nM, and that of tacrine was 1 nM. This study demonstrated that the ursolic acid of Origanum majorana L. appeared to be a potent AChE inhibitor in Alzheimer's Disease.

Acetylcholinesterase↗
PubMed2001

Comparison of the response to the prone position between pulmonary and extrapulmonary acute respiratory distress syndrome.

OBJECTIVES: To determine whether the response to the prone position differs between acute respiratory distress syndrome (ARDS) resulting from a pulmonary cause (ARDSp) and that from an extrapulmonary cause (ARD-Sexp). DESIGN AND SETTING: Prospective observational study in a medical ICU of a university-affiliated hospital. SUBJECTS: A consecutive series of 31 patients with ARDSp and 16 with ARDSexp within 3 days of onset of ARDS. INTERVENTION: Prone position for at least 2 h. MEASUREMENTS AND RESULTS: In ARDSp, compared with the supine position (121 +/- 49 mmHg), PaO2/FIO2 was not increased after 0.5 h but was increased after 2 h in the prone position (158 +/- 60 mmHg). In ARDSexp, compared with the supine position (106 +/- 53 mmHg), PaO2/FIO2 was increased after 0.5 h (155 +/- 91 mmHg), but was not further changed after 2 h. Marked oxygenation response (increase in PaO2/FIO2 > 40% from baseline) after 0.5 h was 23% in ARDSp and 63% in ARDSexp, and that after 2 h was 29% and 63%, respectively. Static respiratory compliance decreased in the prone position in ARDSexp (30 +/- 11 ml/cmH2O at baseline, 27 +/- 11 after 0.5 h and 25 +/- 9 after 2 h) but not in ARDSp. Consolidation score as determined on the first chest radiography taken in the prone position decreased to a greater degree in ARDSexp (-2.4 +/- 4.1) than in ARDSp (0.3 +/- 4.1). CONCLUSION: Pulmonary ARDS and extrapulmonary ARDS in their early stages respond differently to the prone position with regard to the time course of oxygenation, respiratory mechanical behaviour, and radiographic change. These findings suggest that the early pathophysiology of ARDS differs according to the type of primary insult to the lung.

Aged↗
PubMed2001

Ultrasonographic mass screening for thyroid carcinoma: a study in women scheduled to undergo a breast examination.

This study was carried out to clarify the sensitivity of ultrasonographic mass screening for thyroid carcinoma. Between December 1997 and July 1998, a total of 1401 subjects who were scheduled to undergo either a breast examination or a follow-up examination for breast cancer were enrolled in this study. Patients with thyroid nodules were classified into two groups according to their potential risk for malignancy based on the ultrasonographic findings. Ultrasonographic high-risk patients for thyroid cancer underwent an ultrasound guided fine-needle aspiration biopsy (FNAB) and were advised to undergo a thyroidectomy based on the FNAB results. The characteristics of the thyroid cancer patients detected by mass screening were then compared with those of 106 consecutive female patients with clinical thyroid cancer during the same period. Thyroid nodules were detected in 353 (25.2%) of the subjects, 94 (26.6%) of whom were placed in the high-risk group for thyroid cancer. Among the 94 high-risk patients, 43 underwent a thyroidectomy and 37 turned out to have thyroid carcinomas. The detection rate for thyroid cancer was 2.6% for all subjects. The tumor size was significantly smaller than that of the clinically detected cancer group (P < 0.05). Ultrasonographic mass screening for thyroid carcinoma in women who require breast examinations is thus considered to be effective for the detection of subclinical thyroid carcinoma.

Adolescent↗
PubMed2001

Histamine release induced by dendroaspis natriuretic peptide from rat mast cells.

Dendroaspis natriuretic peptide (DNP), recently isolated from the venom of the green Mamba snake Dendroaspis angusticeps, is a 38 amino acid peptide containing a 17 amino acid disulfide ring structure similar to that of the natriuretic peptide family. The natriuretic peptide family is known to induce histamine release from human and rat mast cells, but there are no published data concerning the effects of DNP on histamine release from mast cells. The purpose of this study is to investigate whether DNP induces the histamine release from rat peritoneal mast cells (RMPCs) and to determine the mechanism of DNP-induced histamine release from RPMCs. After treatment of RPMC with DNP, mast cell degranulation was observed, and calcium uptake and histamine release were measured. DNP released the histamine, induced the mast cell degranulation, and increased the calcium uptake of RPMCs, in a dose-dependent manner. The results indicate that DNP can increase Ca-uptake and induce histamine release.

Animals↗
PubMed2001

Comparison of laser epithelial keratomileusis and photorefractive keratectomy for low to moderate myopia.

PURPOSE: To compare the effectiveness, safety, and stability of laser epithelial keratomileusis (LASEK), a modified photorefractive keratectomy (PRK) technique, with those of conventional PRK for low to moderate myopia. SETTING: Department of Ophthalmology, Yonsei University School of Medicine, Seoul, Korea. METHODS: In this prospective study, 27 patients with a manifest refraction of -3.00 to -6.50 diopters were treated and followed for 3 months. In each case, PRK was performed in 1 eye and LASEK in the other eye. The first eye treated and the surgical method used in the first eye were randomized. Postoperative pain, epithelial healing time, uncorrected visual acuity (UCVA), manifest refraction, corneal haze, and surgical preference were examined in PRK- and LASEK-treated eyes. RESULTS: During the 3 month follow-up, there were no significant between-eye differences in epithelial healing time, UCVA, or refractive error. However, LASEK-treated eyes had lower postoperative pain scores (P =.047) and corneal haze scores (1 month; P =.02) than PRK-treated eyes. Seventeen patients (63%) preferred the LASEK procedure. CONCLUSIONS: Laser epithelial keratomileusis safely and effectively treated eyes with low to moderate myopia. It reduced the incidence of significant postoperative pain and corneal haze and may prevent the flap- and interface-related problems of laser in situ keratomileusis.

Adult↗
PubMed2001

Enhanced thermal stability of an alkaline protease, AprP, isolated from a Pseudomonas sp. by mutation at an autoproteolysis site, Ser-331.

The thermal stability of the alkaline protease extracellular subtilisin-type serine protease (AprP) from Pseudomonas sp. KFCC 10818 was improved by altering an amino acid residue at an autoproteolytic cleavage site. N-terminal sequence analysis of the autoproteolytic products of the protein revealed the presence of two cleavage sites, Ser-307 and Ser-331. To increase the thermal stability of the enzyme, serine residues of these sites were replaced with aspartate. The S331D mutant enzyme was successfully purified and characterized whereas the S307D mutant was not. The half-lives of the S331D mutant at 55 degrees C and 60 degrees C were 1.5 and 2.4 times longer than that of the wild-type enzyme, respectively. In addition, the catalytic efficiency was also enhanced.

Alkaline Phosphatase↗
PubMed2001

Natural occurrence of aflatoxins in Korean meju.

Aflatoxin B1 (AFB1) was found in 35 of 60 (58.3%) meju samples with an average concentration of 7.3 ng/g by ELISA. Contamination of AFB1 was confirmed in 25 of 60 samples (41.6%) using HPLC, with an average concentration of 6.9 ng/g. Mean recoveries from meju ranged from 107% to 170% for AFB1 using ELISA at a spiking range of 1 to 50 ng/g. Over the same range, recoveries using HPLC were from 70% to 83%. The levels of AFB1 determined by ELISA and by HPLC demonstrated a close relationship between the two methods (r2 = 0.9324) employed in this study. In order to evaluate the potential health risks of AFB1 on Koreans consuming meju, we calculated the estimated probable daily intake (PDI) based on the average contamination levels and compared it with the estimated tolerable daily intake (TDI). The PDIs of AFB1 from kanjang and dwenjang were determined to be 0.04 and 0.21 ng/kg bw/day, respectively, and were higher than TDIs.

Aflatoxin B1↗
PubMed2001

BIGH3 gene mutations and rapid detection in Korean patients with corneal dystrophy.

PURPOSE: Mutations in the BIGH3 gene on chromosome 5q31 cause four distinct autosomal dominant corneal dystrophies. We sought to determine whether the BIGH3 gene mutation was responsible for corneal dystrophy in Korean patients. METHODS: Polymerase chain reaction single strand conformational polymorphism (PCR-SSCP) analysis was performed with the DNA from patients and healthy individuals. We sequenced the PCR products with the aberrant SSCP pattern to identify the mutation. Mutant-specific reverse primers were used to screen genomic DNA for the identified mutations. RESULTS: We identified mutations R124C in the CDL1 family and R124H in four families with a granular dystrophy. We identified our granular dystrophy to be Avellino corneal dystrophy (ACD). Eighteen of 20 patients with a granular dystrophy contained the same R124H mutation, indicating that mutation R124H was very common in Korean patients with ACD. During this study, we identified a new polymorphism (T1667C, F540F). CONCLUSIONS: This is the first report of mutations found in the BIGH3 gene in Korean families with corneal dystrophy. We report that the majority (90%) of ACD patients in Korea carry the R124H mutation. Mutant-specific reverse primers can be used to screen efficiently for CDL1 and ACD.

Adolescent↗
PubMed2001

Lipase and its modulator from Pseudomonas sp. strain KFCC 10818: proline-to-glutamine substitution at position 112 induces formation of enzymatically active lipase in the absence of the modulator.

A lipase gene, lipK, and a lipase modulator gene, limK, of Pseudomonas sp. strain KFCC 10818 have been cloned, sequenced, and expressed in Escherichia coli. The limK gene is located immediately downstream of the lipK gene. Enzymatically active lipase was produced only in the presence of the limK gene. The effect of the lipase modulator LimK on the expression of active lipase was similar to those of the Pseudomonas subfamily I.1 and I.2 lipase-specific foldases (Lifs). The deduced amino acid sequence of LimK shares low homology (17 to 19%) with the known Pseudomonas Lifs, suggesting that Pseudomonas sp. strain KFCC 10818 is only distantly related to the subfamily I.1 and I.2 Pseudomonas species. Surprisingly, a lipase variant that does not require LimK for its correct folding was isolated in the study to investigate the functional interaction between LipK and LimK. When expressed in the absence of LimK, the P112Q variant of LipK formed an active enzyme and displayed 63% of the activity of wild-type LipK expressed in the presence of LimK. These results suggest that the Pro(112) residue of LipK is involved in a key step of lipase folding. We expect that the novel finding of this study may contribute to future research on efficient expression or refolding of industrially important lipases and on the mechanism of lipase folding.

Bacterial Proteins↗
PubMed2001

Obstetric prognosis of the gestational thrombocytopenia.

To define clinical outcomes of marked gestational thrombocytopenia (GT) (<100,000/mm3) we identified twenty-nine infants born to 28 pregnancies at 26 women with GT among 8,364 deliveries during the years 1993- 1999. Cordocentesis was performed in 7 mothers with platelet counts less than 75,000/mm3. Cord blood platelet count was checked in all cases at delivery. The most significant decrease of platelet count in pregnancy with GT was less than 50,000/mm3 in 6 pregnancies (21.4%) and between 50,000 and 100,000/mm3 in 22 pregnancies (78.6%). In pregnancies with GT, 2 neonates (6.9%) had mild thrombocytopenia and 1 neonate (3.4%) moderate thrombocytopenia. Severe thrombocytopenia was not observed in any neonate born to mothers with GT. There were no cases of coagulation disturbance at delivery or in the postpartum period. Fourteen cases for which follow-up was carried out recovered platelet counts to more than 100,000/mm3 within one month postpartum. Two patients who became pregnant twice noticed recurrence of GT. In conclusion, GT is not associated with bleeding diathesis in the mother, resolves spontaneously during the postpartum period, and can recur in subsequent gestations, and the association of severe fetal/neonatal thrombocytopenia is very rare. No intervention is necessary during pregnancy or delivery, apart from a careful maternal and fetal surveillance if there is no obstetric indication.

Adult↗
PubMed2001

Inducible nitric oxide synthase (iNOS) immunoreactivity and its relationship to cell proliferation, apoptosis, angiogenesis, clinicopathologic characteristics, and patient survival in pancreatic cancer.

BACKGROUND: The clinicopathological and biological significance of the expression of iNOS in pancreatic cancer remains unclear. The goal of this study was to determine the possible roles and clinical significance of iNOS expression in pancreatic cancer. METHODS: Seventy-two pancreatic adenocarcinoma tissue specimens were obtained by surgical resection. We investigated the immunohistochemical expression of iNOS in 72 patients with pancreatic cancer with respect to variable clinicopathological characteristics, proliferation activity (assessed by Ki-67 expression), apoptosis (assessed by TUNEL stain), and microvessel density (assessed by CD34 expression; angiogenesis). RESULTS: Immunohistochemical investigations demonstrated immunolabeling of tumor cells with anti-iNOS antibody. Positivity for iNOS was observed in 48/72 (66.7%). The expression of iNOS protein did not correlate with age, bilirubin, tumor marker, location, size, AJCC stage, differentiation, distant metastasis, or patient survival. No significant association was found between iNOS expression and proliferation or microvessel density in pancreatic cancer. Apoptotic index (AI) of positive iNOS expressions were significantly higher than negative expression (p < 0.001). CONCLUSION: Inducible nitric oxide synthase (iNOS) is expressed by human pancreatic cancer, and its presence is positively correlated with apoptosis of cancer cells that could provide the basis for the development of therapeutic strategies in human pancreatic cancer.

Adenocarcinoma↗
PubMed2001

Protective effect of 4',5-dihydroxy-3',6,7-trimethoxyflavone from Artemisia asiatica against Abeta-induced oxidative stress in PC12 cells.

Amyloid beta protein (Abeta)-induced free radical-mediated neurotoxicity is a leading hypothesis as a cause of Alzheimer's disease (AD). Abeta increased free radical production and lipid peroxidation in PC12 nerve cells, leading to apoptosis and cell death. The effect of 4',5-dihydroxy-3',6,7-trimethoxyflavone from Artemisia asiatica on Abeta induced neurotoxicity was investigated using PC12 cells. Pretreatment with isolated 4',5-dihydroxy-3',6,7-trimethoxyflavone and vitamin E prevented the Abeta-induced reactive oxygen species (ROS). The 4',5-dihydroxy-3',6,7-trimethoxyflavone resulted in concentration-dependant decreased Abeta toxicity assessed by 3-(4, 5- dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. However, treatment with these antioxidants inhibited the Abeta-induced neurotoxic effect. Therefore, these results indicate that micromolecular Abeta-induced oxidative cell stress is reduced by 4,5-dihydroxy-3',6,7-trimethoxyflavone from Artemisia asiatica.

Adrenal Medulla↗