Biomedical subjects

E Y Kim

Publications and source records attributed to E Y Kim.

At least 37 records · Page 2Linked to original sources

PubMed2000

Glutamine-dependent antiapoptotic interaction of human glutaminyl-tRNA synthetase with apoptosis signal-regulating kinase 1.

Glutamine has been known to be an apoptosis suppressor, since it blocks apoptosis induced by heat shock, irradiation, and c-Myc overexpression. Here, we demonstrated that HeLa cells were susceptible to Fas-mediated apoptosis under the condition of glutamine deprivation. Fas ligation activated apoptosis signal-regulating kinase 1 (ASK1) and c-Jun N-terminal kinase (JNK; also known as stress-activated protein kinase (SAPK)) in Gln-deprived cells but not in normal cells, suggesting that Gln might be involved in the activity control of ASK1 and JNK/SAPK. As one of the possible mechanisms for the suppressive effect of Gln on ASK1, we investigated the molecular interaction between human glutaminyl-tRNA synthetase (QRS) and ASK1 and found the Gln-dependent association of the two molecules. While their association was enhanced by the elevation of Gln concentration, they were dissociated by Fas ligation within 5 min. The association involved the catalytic domains of the two enzymes. The ASK1 activity was inhibited by the interaction with QRS as determined by in vitro kinase and transcription assays. Finally, we have shown that QRS inhibited the cell death induced by ASK1, and this antiapoptotic function of QRS was weakened by the deprivation of Gln. Thus, the antiapoptotic interaction of QRS with ASK1 is controlled positively by the cellular concentration of Gln and negatively by Fas ligation. The results of this work provide one possible explanation for the working mechanism of the antiapoptotic activity of Gln and suggest a novel function of mammalian ARSs.

Amino Acyl-tRNA Synthetases↗

PubMed2000

Introduction of HIV type 1 subtype E virus into South Korea.

Subtype E HIV-1 is the most prevalent strain in Southeast Asia. Although subtype B is prevalent in Korea, geographical distance and increases in travel may lead to the spread of subtype E in Korea. Therefore, we tried to identify and monitor the patterns of HIV subtype E virus introduction into Korea. The divergence of nucleotide sequences within the envelope region (V3 to V5) of Korean subtype E isolates ranged from 4.3 to 14.6% (n = 8; mean, 9.5 +/- 2.8%). In pairwise comparisons of subtype E isolates between Korea and other regions, the divergence of nucleotide sequences between 8 Korean and 16 Asian subtype E variants ranged from 1.3 to 15.2% (mean, 7.8 +/- 2.6%), whereas the divergence of nucleotide sequences between 8 Korean and 2 African variants ranged from 11.7 to 20.7% (mean, 15.4 +/- 2.2%). A phylogenetic tree showed that Korean subtype E isolates cluster with the Asian isolates but far from the African isolates. These epidemiological and molecular epidemiological data suggest that HIV-1 subtype E strains have been transmitted into Korea from endemic areas of Southeast Asia rather from Africa.

Adult↗

PubMed2000

Spinal clear cell meningioma presented with progressive paraparesis in infancy.

Clear cell meningioma, about 20 cases of which have been reported in the literature, is a morphological variant of meningioma. The authors report a case of spinal clear cell meningioma that occurred in a child. A 14-month-old girl showed gradually progressive paraparesis 1 month after she started to walk. Magnetic resonance image showed an intradural extramedullary mass compressing the conus medullaris and cauda equina. Complete excision of the tumor was done, and the patient gradually recovered from motor weakness and neurogenic bladder. Histological examinations along with immunohistochemical and ultrastructural investigations allowed a diagnosis of clear cell meningioma. During the follow-up period, a recurrent mass lesion was detected on the 8-month follow-up MR image in the same region. Because clear cell meningioma might be biologically aggressive, postoperative adjuvant therapy and close follow-up investigation should be considered.

Female↗

PubMed2000

Improved immobilization yields by addition of protecting agents in glutaraldehyde-induced immobilization of protease.

The effects of peptides and polyethylene glycol (PEG) on the immobilization of protease using glutaraldehyde-activated Lewatit R258-K resin were investigated. When soy peptide was added at 0.1 g/l, the activity recovery and effectiveness factor increased by 20% and 38%, respectively. When PEG4000 (0.5 g/l) was used as a protecting agent, the activity recovery and effectiveness factor were improved by 35% and 60%, respectively, leading to an increased specific activity of the immobilized enzyme. The addition of PEG4000 is suggested to improve the cost-effectiveness for the production of immobilized enzymes.

Journal Article↗

PubMed2000

The distribution and requirements of microtubules and microfilaments in bovine oocytes during in vitro maturation.

Microtubules and microfilaments are major cytoskeletal components and important modulators for chromosomal movement and cellular division in mammalian oocytes. In this study we observed microtubule and microfilament organisation in bovine oocytes by laser scanning confocal microscopy, and determined requirements of their assembly during in vitro maturation. After germinal vesicle breakdown, small microtubular asters were observed near the condensed chromatin. The asters appeared to elongate and encompass condensed chromatin particles. At the metaphase stage, microtubules were observed in the second meiotic spindle at the metaphase stage. The meiotic spindle was a symmetrical, barrel-shaped structure containing anastral broad poles, located peripherally and radially oriented. Treatment with nocodazole did not inhibit germinal vesicle breakdown. However, progression to metaphase failed to occur in oocytes treated with nocodazole. In contrast, microfilaments were observed as a relatively thick uniform area around the cell cortex and overlying chromatin following germinal vesicle breakdown. Treatment with cytochalasin B inhibited microfilament polymerisation but did not prevent either germinal vesicle breakdown or metaphase formation. However, movement of chromatin to the proper position was inhibited in oocytes treated with cytochalasin B. These results suggest that both microtubules and microfilaments are closely associated with reconstruction and proper positioning of chromatin during meiotic maturation in bovine oocytes.

Actin Cytoskeleton↗

PubMed2000

Synergetic activation of p38 mitogen-activated protein kinase and caspase-3-like proteases for execution of calyculin A-induced apoptosis but not N-methyl-d-aspartate-induced necrosis in mouse cortical neurons.

We examined the possibility that p38 mitogen-activated protein kinase and caspase-3 would be activated for execution of apoptosis and excitotoxicity, the two major types of neuronal death underlying hypoxicischemic and neurodegenerative diseases. Mouse cortical cell cultures underwent widespread neuronal apoptosis 24 h following exposure to 10-30 nM calyculin A, a selective inhibitor of Ser/Thr phosphatase I and IIA. Activity of p38 was increased 2-4 h following exposure to 30 nM calyculin A. Addition of 3-10 microM PD169316, a selective p38 inhibitor, partially attenuated calyculin A neurotoxicity. Activity of caspase-3-like proteases was increased in cortical cell cultures exposed to 30 nM calyculin A for 8-16 h as shown by cleavage of DEVD-p-nitroanilide and phosphorylated tau. Proteolysis of tau was completely blocked by addition of 100 microM N-benzyloxycarbonyl-Val-Ala-Asp-fluoromethyl ketone (z-VAD-fmk), a broad-spectrum inhibitor of caspases, but incompletely by 10 microM PD169316. Calyculin A neurotoxicity was partially sensitive to 100 microM z-VAD-fmk. Cotreatment with 10 microM PD169316 and 100 microM z-VAD-fmk showed additive neuroprotection against calyculin A. Neither PD169316 nor z-VAD-fmk showed a beneficial effect against excitotoxic neuronal necrosis induced by exposure to 20 microM NMDA. Thus, caspase-3-like proteases and p38 likely contribute to calyculin A-induced neuronal apoptosis but not NMDA-induced neuronal necrosis.

Amino Acid Chloromethyl Ketones↗

PubMed2000

Haloperidol-induced neuronal apoptosis: role of p38 and c-Jun-NH(2)-terminal protein kinase.

We examined patterns and mechanisms of cell death induced by haloperidol. Cortical cell cultures exposed to 10-100 microM: haloperidol for 24 h underwent neuronal death without injuring glia. The degenerating neurons showed hallmarks of apoptosis, featuring cell body shrinkage, nuclear chromatin condensation and aggregation, nuclear membrane disintegration with intact plasma membrane, and prominent internucleosomal DNA fragmentation. Neither glutamate antagonists nor antioxidants prevented the haloperidol-induced neuronal apoptosis. The c-Jun-NH(2)-terminal protein kinase and p38 mitogen-activated protein kinase were activated within 1 h and were sustained over the next 3 h following exposure of cortical neurons to 30 microM haloperidol. Haloperidol-induced neuronal apoptosis was partially attenuated by 10-30 microM PD169316, a selective inhibitor of p38 mitogen-activated protein kinase. Inclusion of 1 microg/ml cycloheximide, a protein synthesis inhibitor, or 100 ng/ml insulin prevented activation of both kinases and subsequent neuronal death. The present study demonstrates that cortical neurons exposed to haloperidol undergo apoptosis depending on activation of p38 mitogen-activated protein kinase and c-Jun-NH(2)-terminal protein kinase sensitive to cycloheximide and insulin.

Animals↗

PubMed2000

Infantile fibromatosis in childhood: findings on MR imaging and pathologic correlation.

AIM: The objective of this study was to analyse the MR imaging findings of infantile fibromatosis of childhood and to correlate them with histopathological features. MATERIALS AND METHODS: Seven patients with histologically proven infantile fibromatosis were included in this study. The findings on MR images were retrospectively evaluated and then correlated with the pathological features. Findings on MR imaging evaluated included signal intensity, extent of hyperintense area on T2-weighted images, margins of the lesion, the degree and pattern of enhancement and the presence of fatty tissue. Pathological features evaluated included cellularity, collagenization, and myxoid change. A five point scale was used for the evaluation of the extent of hyperintense area on MR imaging, and each of pathological features. RESULTS: On T1-weighted images, the lesions were iso-intense in two patients; iso- and hypointense in three; and iso-, hypo- and hyperintense in two. On T2-weighted images, iso-, hypo- and hyperintense areas were mixed in all patients, the hyperintense area being the largest portion of the lesion. The margins of the lesions were infiltrative in four patients (57%), smooth in two (29%) and mixed in one (14%). Enhancement was marked in five patients (72%) and diffuse in five (71%). Regardless of the hyperintense signal intensity on T2-weighted images, the grades of each pathologic feature were variable. CONCLUSION: Infantile fibromatosis on MR imaging causes an enhancing mass, that is largely hyperintense on T2-weighted images. Areas of high signal intensity on T2-weighted images corresponded to variable grades of cellularity, collagenization, or myxoid change.

Child↗

PubMed2000

Ultra-rapid freezing of human multipronuclear zygotes using electron microscope grids.

Developmental capacity of human multipronuclear (PN) zygotes cryopreserved using an ultra-rapid freezing method and electron microscope (EM) grids was studied. Multipronuclear zygotes obtained from a human IVF programme were used as an alternative to normal 2PN zygotes; they were divided into 3PN or >or =4PN zygotes and their in-vitro development and cryo-injury were compared according to PN number. EFS30, which consisted of 30% ethylene glycol, 18% Ficoll, 0. 5 mol/l sucrose and 10% fetal bovine serum with added modified Dulbecco's phosphate buffered saline was used as the freezing solution. After ultra-rapid freezing and thawing 85.5% of multipronuclear zygotes survived. A comparison of cleavage rates between the control and cryopreserved groups showed no significant difference (3PN; 81.3 and 85.4% and > or =4PN; 90.0 and 95.7% respectively). Comparing the in-vitro development after thawing up to blastocyst formation on day 5 after IVF, the outcome of the frozen 3PN group (22.0%) was not different from that of control 3PN group (38.5%), while the outcome of the frozen > or =4PN group (4.5%) was significantly lower than that of control > or =4PN group (44.4%) (P < 0.05).

Cell Nucleus↗

PubMed2000

Dysplastic nodules in liver cirrhosis: evaluation of hemodynamics with CT during arterial portography and CT hepatic arteriography.

PURPOSE: To evaluate the portal and arterial blood supplies to dysplastic nodules in the cirrhotic liver with computed tomography (CT) during arterial portography (CTAP) and CT hepatic arteriography (CTHA). MATERIALS AND METHODS: Nineteen histopathologically proved low-grade dysplastic nodules and 13 high-grade dysplastic nodules in 17 patients with liver cirrhosis were evaluated with CTAP and CTHA for the presence of portal and arterial blood supplies to the nodules. The nodules ranged from 0.4 to 4.5 cm in diameter (mean, 1.6 cm). RESULTS: The portal supply was present in 14 of the 19 (74%) low-grade dysplastic nodules and in seven of the 13 (54%) high-grade dysplastic nodules. The hepatic arterial supply was increased in four of the 19 (21%) low-grade dysplastic nodules, present in nine (47%), and absent in six (32%). The arterial supply was increased in four of the 13 (31%) high-grade dysplastic nodules, present in four (31%), and absent in five (38%). CONCLUSION: The portal and arterial supplies to the low- and high-grade dysplastic nodules were variable and inconsistent. Therefore, it is difficult to detect and characterize the dysplastic nodules on the radiologic images on the basis of the blood supply.

Adult↗

PubMed2000

The frequency of mutation in CCR5 gene among Koreans.

To better understand a role of the delta32 allele of the CCR5 gene in HIV-1 transmission and disease progression, we determined the CCR5 genotypes within several groups of Koreans. Amplification of DNA from each subject was achieved with polymerase chain reaction, using the CCR5 specific primer pair, which flanks the 32 bp deletion. The 1.2 kb coding sequences of CCR5 were examined to see the possible effects of CCR5 polymorphism. All of the 339 healthy, HIV-uninfected individuals had no mutation in the CCR5 gene. All of the 115 HIV-1-infected patients including 11 long-term non-progressors (LTNPs) and 18 discordant spouses were also wild homozygotes. No variation in the 1.2kb CCR5 coding sequence was found in 5 LTNPs and 5 discordant spouses. In conclusion, the 32 bp deletion mutant is rarely present in Koreans. Our data suggest that factors other than the CCR5 coding sequences may also play a role in the resistance to HIV infection.

Alleles↗

PubMed2000

Acute diverticulitis of the cecum and ascending colon: the value of thin-section helical CT findings in excluding colonic carcinoma.

OBJECTIVE: The purpose of this study was to assess the value of characteristic thin-section helical CT findings of acute diverticulitis involving the cecum and ascending colon in excluding colonic carcinoma. MATERIALS AND METHODS: Thin-section helical CT scans (5-mm collimation) of 19 consecutive patients with proven diverticulitis and 21 consecutive patients with surgically proven carcinoma involving the cecum and ascending colon were reviewed retrospectively. Two radiologists independently analyzed these parameters: degree of pericolic infiltration, mesenteric fluid, vascular engorgement, arrowhead-shaped wall thickening, air-filled diverticula, inflamed diverticula, and preserved enhancement pattern of involved colonic wall. Inter-observer agreement was assessed with a kappa statistical analysis, and the features that most distinguished diverticulitis from colonic carcinoma were selected with a stepwise logistic-regression analysis. RESULTS: The two CT findings of right-sided colonic diverticulitis that most distinguished it from colonic carcinoma were inflamed diverticula and the preservation of an enhancement pattern of the involved colonic wall. Excellent interobserver agreement (kappa > 0.60) was obtained for both findings. Inflamed diverticula (kappa = 0.80) had a mean sensitivity, specificity, and accuracy for diverticulitis of 86.8%, 92.9%, and 90.0%, respectively, in differentiating right-sided colonic diverticulitis from colonic carcinoma. Preserved wall enhancement pattern (kappa = 0.70) had a mean sensitivity, specificity, and accuracy of 89.5%, 95.3%, and 92.5%, respectively. CONCLUSION: On thin-section helical CT, an inflamed diverticula and a preserved enhancement pattern of the thickened colonic wall were the two most statistically significant CT findings of acute diverticulitis involving the cecum and ascending colon that distinguished diverticulitis from colonic carcinoma.

Acute Disease↗

PubMed2000

Metastatic renal cell carcinoma in a meningioma: a case report.

Tumor-to-tumor metastasis is rare. We report a case of metastatic renal cell carcinoma in meningioma. A 67-year-old woman presented a two-week history of motor dysphagia and decreased short-term memory. She had undergone a left radical nephrectomy for a renal cell carcinoma 7 years ago, and had not received any adjuvant therapy. MRI disclosed a 3.0 x 3.0 x 3.0-cm sized round tentorial-based extraaxial mass with peritumoral edema in the left posterior temporal lobe. During operation, the tumor was found to be an encapsulated mass firmly attached to the tentorium. Histologically, the tumor was a meningotheliomatous meningioma extensively infiltrated by metastatic renal cell carcinoma, accompanying widespread coagulative necrosis. Immunohistochemical staining for cytokeratin revealed strong positivity only in the renal cell carcinoma component. The patient's postoperative course was uneventful. Post-operative radiation therapy was applied to the whole brain. Three months after operation, the patient developed right hemiparesis and dysphagia. Brain MRI at that time did not reveal recurrence or any other causative lesions, although the whole body scan disclosed uptake at the second lumbar vertebra and rib. The patient refused further treatment.

Aged↗

PubMed2000

Ultrasonographic evaluation of focal hepatic lesions: comparison of pulse inversion harmonic, tissue harmonic, and conventional imaging techniques.

A prospective study was performed to evaluate whether pulse inversion harmonic imaging and tissue harmonic imaging improve the lesion conspicuity and change ultrasonographic characteristics of focal hepatic lesions. Three radiologists evaluated 97 focal hepatic lesions by consensus: cirrhosis-related nodules (n = 23), metastases (n = 23), hemangiomas (n = 27), and cysts (n = 24). In our study, pulse inversion harmonic imaging was judged superior to both tissue harmonic imaging and conventional imaging in conspicuity and overall quality for cirrhosis-related nodules, metastases, and cysts (P < 0.05). Compared with conventional imaging, both pulse inversion harmonic imaging and tissue harmonic imaging provided better conspicuity, clearer internal echogenicity, and stronger through-transmission of cysts (P < 0.05). Pulse inversion harmonic imaging was judged to be better in depicting internal morphology for cirrhosis-related nodules and metastases than conventional imaging (P < 0.05). For hemangiomas, no statistically significant difference was found in all parameters except better posterior enhancement by tissue harmonic imaging than other techniques. In conclusion, pulse inversion harmonic imaging showed the best conspicuity and also enhanced characteristics of both cystic and solid hepatic lesions. Tissue harmonic imaging was judged superior to conventional imaging in evaluating cysts but was not beneficial for solid lesions. The results of this trial may be specific to the machine used for this study.

Adult↗

PubMed2000

The relationship between the Y chromosome size and the amount of autosomal Q-heterochromatin in human populations.

The relationship between the basic quantitative characteristics of the Q-heterochromatin (Q-HR) region variability of autosomes and of the Y chromosome in human populations was examined. A definite relationship between the mean number of Q-HR per individual, the distribution and frequencies of Q-HR on autosomes and the size of the Q-heterochromatin segment of the Y chromosome at the population level was shown to exist. The amount of autosomal Q-HR was lower in individuals with larger Q-heterochromatin segments on Y chromosomes, and vice versa. The hypothesis that the amount of chromosomal Q-HR in the genome of modern human populations may be under the control of natural selection, is discussed.

Adolescent↗

PubMed2000

Introduction of human immunodeficiency virus 2 infection into South Korea.

Although human immunodeficiency viruses 1 and 2 (HIV-1 and HIV-2) share mode of transmission, their epidemiologic characteristics differ and international spread of HIV-2 has been limited. To investigate the extent of HIV-2 infection in South Korea and to clarify the characteristic of HIV-2 isolates, we describe epidemiological, serological and genetic analyses of five HIV-2 isolates from South Korea. Five of 964 HIV antibody-positive serum specimens showed positive reactivity by HIV1/2 enzyme immunoassay (EIA), HIV-2 Western blot analysis, HIV-2 particle agglutination (PA) test and line immunoassay (LIA) but negative or indeterminate one by HIV-1 PA test and HIV-1 Western blot analysis. To confirm HIV-2 infection by genetic analysis, reverse transcription-polymerase chain reaction (RT-PCR) was performed on five HIV-2 seropositive samples. PCR products from gag (197 bp) and env gene regions (137 bp) were obtained with three of the five samples with HIV-2 specific gag primers and with all the five samples with env primers. To obtain larger sequences for a more comprehensive phylogenetic analysis, we performed PCR for a 1191 bp env region of HIV-2 but only two such products were obtained. For the phylogenetic analysis, three 197 bp gag and two 1191 bp env PCR products were cloned and sequenced. Based on the gag and env sequences alignments, three isolates (KR4063, KR7051 and KR8091) were clustered phylogenetically within HIV-2 subtype A. In conclusion, HIV-2 virus is present in South Korea and was detected in five subjects. Furthermore, the prevalence of HIV-2 infection should be monitored continuously in South Korea to assess the spread of this virus and to assist in the diagnosis of HIV infection.

Adult↗

PubMed1999

Survey of the Korean population for 9 short tandem repeat loci.

The short tandem repeats with repeat units ranging from two to several nucleotides became a powerful tool in the field of forensic identification and paternity determination as well as for research in human gene mapping. Allele and genotype frequencies for 9 short tandem repeats including HUMCSF1PO, HUMTH01, HUMPLA2A1, HUMF13A01, HUMCYAR04, HUMLIPOL, HUMHPRTB, HUMCD4, and HUMFABP were determined using PCR and subsequent analysis of the PCR products by denaturing polyacrylamide gel electrophoresis followed by silver-staining. DNA samples were obtained from about 100 Korean people and amplified in a thermocycler adopting glass capillaries rather than traditional tubes. We found that the bovine serum albumin was an essential additive for the capillary PCR, presumably to coat the inner surface of the capillary which may adsorb Taq DNA polymerase. The capillary thermocycler was very effective in reducing the cycling time such that most of the amplification reactions could be finished within 30 min albeit the PCR product was less than that for the tube systems. All loci except HUMHPRTB met the Hardy-Weinberg expectations according to the exact test. The cumulative power of discrimination (PD) was 0.9999998 and the power of exclusion (POE) for the paternity test was a little low, being 0.9873989.

Alleles↗

PubMed1999

Neuroprotective effect of high glucose against NMDA, free radical, and oxygen-glucose deprivation through enhanced mitochondrial potentials.

Cultured cortical neurons maintained in 25 mM glucose underwent a widespread neuronal death after exposure to NMDA, AMPA, and kainate. Among these, NMDA toxicity was substantially reduced in neurons maintained in 100 mM glucose. NMDA-induced increase in [Ca(2+)](i) and reactive oxygen species was attenuated in neurons maintained in high glucose that revealed increased mitochondrial membrane and redox potentials as determined using rhodamine 123 and 3-(4, 5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide. p-trifluoromethoxy-phenylhydrazone, KCN, and rotenone, the selective inhibitors of mitochondrial potential, abrogated neuroprotective effect of high glucose against NMDA. The neuroprotective action of high glucose was extended against oxygen or combined oxygen-glucose deprivation. The present study provides evidence that prolonged exposure of cortical cells to high glucose attenuates NMDA- and free radical-mediated neuronal death via enhanced mitochondrial function.

Animals↗