Biomedical subjects

I S Kim

Publications and source records attributed to I S Kim.

At least 19 recordsLinked to original sources

PubMed1998

Subunit composition and oligomer stability of oat beta-glucosidase isozymes.

Oat beta-glucosidase (EC 3.2.1.21) has two isomeric forms, type I and type II, which are composed of 60 kDa peptides. To study the subunit composition and the stability of multimeric structure, the type I and II were purified from the primary leaves and coleoptiles of the etiolated oat seedlings where the isozymes are expressed organ-specifically. The monomers of the isozymes were isolated by urea-denatured gel electrophoresis followed by electroblotting. N-Terminal amino acid sequencing of the monomers indicated that the type I consisted of a peptide of ALESAKQVKPWQVPKRDWFP (As-Glu 1), and the type II having a peptide of ALESGKLKPWQIPKRDWFP (As-Glu 2) and As-Glu 1 in 1:1 ratio. The C-terminal amino acid of the As-Glu 1 was alanine and that of the As-Glu 2 was lysine. The As-Glu 2 was more negatively charged than the As-Glu 1. The type I isozyme is thus homomultimer of As-Glu 1 monomer and the type II heteromultimer of As-Glu 1 and As-Glu 2 monomers in 1:1 ratio. Partial denaturation of the multimers with urea and CaCl2 broke down the higher multimers to the lower multimers, which were in turn dissociated into homodimers and heterodimer. Denaturation study with urea and CaCl2 indicate that the higher multimers of the homooligomeric type I were more stable than those of the heterooligomeric type II and that hydrophobic interactions were important in the multimer formation. The homodimers were found to be more stable than the heterodimer. These results indicate that different combinations of the As-Glu 1 and As-Glu 2 monomers form the two isozymes of oat beta-glucosidase with different enzymatic properties and structural stability.

Amino Acid Sequence↗

PubMed1998

Identification and characterization of the inducible murine mast cell gene, imc-415.

Activation of mast cells results in the generation and release of bioactive mediators which in turn initiate allergic inflammation. Mast cell function is enhanced following stimulation in part because of the induction of specific genes and their products. To identify additional genes induced in mast cells that support this process, we thus constructed an activation-specific mast cell subtraction library. To date, we have isolated 26 novel inducible murine mast cell (imc) cDNA clones. Among them, a full-coding region of the murine gene imc-415 was found to have a greater than 90% nucleotide sequence homology and a 97.5% amino acid sequence homology to both a human beta4 integrin-binding protein (p27(BBP)) and a human translation initiation factor 6 (eIF6), which in turn are identical. In vitro translation of the imc-415 gene yielded a band of an approximately 26 kDa. This is the same as the calculated molecular weight of murine IMC-415 protein based on the predicted amino acid sequence and is the molecular weight of p27(BBP)/eIF6. Murine imc-415 message was also induced in inflamed lung tissues in a mouse model of asthma. These results suggest a role for murine imc-415 in allergic inflammation where it may enhance protein synthesis. Human eIF6/p27(BBP) may also play a role in allergic diseases based on the similarities in sequence and in gene expression patterns.

Amino Acid Sequence↗

PubMed1998

A human transferrin-binding protein of Staphylococcus aureus is immunogenic in vivo and has an epitope in common with human transferrin receptor.

To understand human immune responses against the human transferrin-binding protein of Staphylococcus aureus (SA-tbp), we examined cell wall proteins from S. aureus ATCC 6538 using human convalescent sera, and a monoclonal antibody specific for human transferrin receptor (McAb-HTR). The SA-tbp, detected by immunoblot assay, was iron-repressible, reacted with the convalescent sera, and cross-reacted with McAb-HTR. Immunoelectron microscopy probed with McAb-HTR showed a reaction zone around the test strain from the deferrated BHI. After being preincubated with an S. aureus-bacteremic serum, the electroblot of the SA-tbp still reacted with McAb-HTR, but not with human transferrin-horseradish peroxidase conjugate. We conclude, there are at least two kinds of epitopes in the SA-tbp; one able to bind to human transferrin is immunogenic in humans, but the other sharing epitopes common with human transferrin receptor is not immunogenic in humans.

Antibodies, Bacterial↗

PubMed1998

Iron repressibility of siderophore and transferrin-binding protein in Staphylococcus aureus.

In order to investigate whether the iron acquisition mechanisms of Staphylococcus aureus are induced by iron restriction in vitro, we examined S. aureus ATCC 6538 for production of siderophore and expression of transferrin-binding protein (SA-tbp) in normal or deferrated brain heart infusion broth (BHI). Siderophore production was earlier and greater in the deferrated BHI. The SA-tbp, detected by ligand blot assay, was expressed only in the deferrated BHI. When human transferrin was added to the deferrated BHI, siderophore production was later and lower than when transferrin was not present. In conclusion, both iron acquisition mechanisms of S. aureus were found to be iron-repressible and via both of them, human transferrin-bound iron was utilized for growth under iron-restricted condition.

2,2'-Dipyridyl↗

PubMed1998

Characterization of the leupeptin-inactivating enzyme from Streptomyces exfoliatus SMF13 which produces leupeptin.

Leupeptin-inactivating enzyme (LIE) was purified from Streptomyces exfoliatus SMF13 by ammonium sulphate fractionation of cell-free culture broth, ultrafiltration, anion-exchange chromatography on DEAE-Sephadex A-50 and gel filtration chromatography on Sephadex G-75. The molecular mass of the purified enzyme was measured as 34700 Da and the N-terminal amino acid sequence was APTPPDIPLANVPA. Acetyl-leucine, leucine and argininal were identified as the products of leupeptin inactivated by the LIE, indicating that leupeptin is inactivated by hydrolysis of peptide bond between leucine and leucine and between leucine and argininal of leupeptin (acetyl-leucine-leucine-argininal). Synthetic-peptide substrates specificity of LIE showed that LIE has absolute specificity for peptide bonds with leucine in the P1 position, suggesting that LIE is a leucine-specific protease. The optimum pH and temperature were pH 9.0 and 45 degrees C, respectively. LIE activity was inhibited by metalloprotease inhibitors such as EDTA, EGTA, o-phenanthroline and bestatin, but activated by Mg2+ and Ca2+, suggesting that the enzyme is a metalloprotease. Aerial-mycelium growth and aerial spore formation of S. exfoliatus SMF13 were inhibited by the addition of bestatin, an inhibitor of LIE. The inhibition of morphological differentiation was due to the inhibition of trypsin-like protease (TLP) activity, which is essential for aerial-mycelium formation and is inhibited specifically by remaining leupeptin that was not inactivated. These results show that LIEs play a role in controlling the amount of leupeptin during colony development. Therefore, it is suggested that the physiological function of LIE is to inactivate leupeptin when or where TLP activity is required for aerial-mycelium formation.

Amino Acid Sequence↗

PubMed1998

Cross-reactivity of antibodies immunoadsorbed to laminin with recombinant human La (SS-B) protein.

Anti-La (SS-B) antibodies cross-reacting with mouse B1 laminin were reported in sera of patients with systemic lupus erythematosus. However, the common epitope had not been characterized. Immunoblotting conditions were established, allowing detection and elution of anti-La (SS-B)/laminin cross-reacting antibodies. Antibodies adsorbed to mouse B1 laminin represented a subclass of anti-La antibodies. They strongly reacted with human full length recombinant La protein. However, they failed to react with either an N-terminal La peptide consisting of amino acids 1-192 or a C-terminal La peptide starting at methionine 223, while they still reacted with recombinant La peptides consisting of the amino acids 1-341 or starting at 192. These data indicate that the La (SS-B)/laminin epitope is located between amino acids 192-223 of human La protein, which includes the amino acids EAKLRA, common to the nuclear autoantigen La (SS-B) and the human or mouse B1 laminin.

Amino Acid Sequence↗

PubMed1998

Similarities in the biodistribution of iodine-labeled anti-Tac single-chain disulfide-stabilized Fv fragment and anti-Tac disulfide-stabilized Fv fragment.

We evaluated the biodistribution and pharmacokinetics of two different iodine-labeled Fv fragments of anti-Tac monoclonal antibody (MAb) in normal and tumor-bearing nude mice. One was a disulfide-stabilized Fv fragment (dsFv), and the other was a single-chain disulfide-stabilized Fv fragment (scdsFv). The scdsFv is a newly developed type of Fv fragment superior to the dsFv in which the VH and VL are linked by covalent bonds through a spacer arm and by an internal disulfide bond. These modifications increase the yield of scdsFv. Both reagents recognize the alpha subunit of the interleukin-2 receptor (IL-2Ralpha). The biodistribution of the Fv fragments was evaluated in normal mice co-injected with 50 mg of L-lysine and in a no-lysine control group. Biodistribution was also evaluated in nude mice bearing subcutaneous tumor xenografts derived from IL-2Ralpha-positive ATAC4 cells and receptor-negative A431 cells. These mice were co-injected with 125I-labeled anti-Tac scdsFv (6 microCi/0.7 microg) and 131I-labeled anti-Tac dsFv (2 microCi/0.7 microg) or with 131I-labeled anti-Tac scdsFv (6 microCi/0.7 microg) and 125I-labeled anti-Tac dsFv (4 microCi/0.7 microg). The biodistribution of 125I-labeled anti-Tac scdsFv and 131I-labeled anti-Tac dsFv was very similar in all organs and the tumors. The renal uptake of both reagents was blocked effectively (<93%) and similarly by lysine. The scdsFv cleared slightly faster from the circulation than did the dsFv because there were more aggregates of dsFv than of scdsFv (3% vs. 1%, respectively). The scdsFv-to-dsFv ratio ranged from 0.79 to 1.20 in all organs at all time points we examined. In conclusion, the first biodistribution study of an scdsFv molecule shows that the scdsFv had a biodistribution very similar to that of the dsFv and seems to be a good alternative to the dsFv because of its higher production yield.

Animals↗

PubMed1998

Use of 99mTc-mercaptoacetyltriglycine (MAG3)-biocytin hepatobiliary scintigraphy to study the protective effect of a synthetic enzyme inhibitor on acute hepatotoxicity in mice.

Recent data suggest that inhibitors of ethanol-inducible cytochrome P450 (CYP2E1) can protect the liver from injury caused by various substrates of CYP2E1. In this study, we measured the protective effect of isopropyl-2-(1,3-dithioetane-2-ylidene)-2[N-(4-methylthiazol -2-yl)-carbamoyl]acetate (YH439), a transcriptional inhibitor of CYP2E1, against carbon tetrachloride (CCl4)-induced hepatotoxicity by using various conventional methods and dynamic scintigraphy with 99mTc-mercaptoacetyltriglycine (MAG3)-biocytin, a recently developed scintigraphic agent. Balb/c mice were pretreated with two doses of YH439 (50 or 150 mg/kg per day) at 48 h and 24 h and one dose of CCl4 (0.25 mL/kg) at 18 h before scintigraphy. The results were compared with those of two other groups, one that received CCl4 but not YH439, and the other that received neither (control). Scintigraphic images were acquired continuously at 15-sec intervals for 30 min. Pharmacokinetic parameters, such as peak liver/heart ratio (r(max)), peak liver uptake time (t(max)), and hepatic half-clearance time (HCT), were obtained from time-activity curves derived from regions-of-interest (ROI) over the liver and the heart. Acute administration of CCl4 alone caused centrilobular necrosis and serum transaminase levels to rise more than 5 times higher than those of the control group. Pharmacokinetic parameters also changed significantly from those of the control group. Administration of YH439 prevented centrilobular necrosis and significantly improved pharmacokinetic parameters. This study demonstrates for the first time that hepatobiliary scintigraphy can be used to study in vivo biochemistry of the CYP2E1 inhibitor (YH439) against liver toxicity.

Animals↗

PubMed1998

Prevalence of cardiovascular risk factors in South Korean adults: results from the Korea Medical Insurance Corporation (KMIC) Study.

PURPOSE: To estimate the prevalence of cardiovascular risk factors in South Korea. METHODS: Data were obtained from the Korea Medical Insurance Corporation (KMIC) which provides insurance to civil servants and private school workers. The study sample included female workers, ages 35 to 59 (n = 67,861), and a systematic random sample of insured male workers, ages 35 to 59 (n = 115,200), who attended insurance examinations in 1990 and 1992. Prevalence estimates were age-adjusted to reflect the Korean population, ages 35 to 59, in 1990. RESULTS: The prevalence of hypertension (systolic blood pressure > or = 140 mmHg and/or diastolic blood pressure > or = 90 mmHg) was 28.9% in men and 15.9% in women. The prevalence of hypercholesterolemia (total cholesterol > or = 240 mg/dl) was 8.9% and 10.4% in men and women, respectively. Smoking was highly prevalent in men (57.4%) and uncommon in women (0.6%). The prevalence of a fasting blood sugar > or = 126 mg/dl was 4.7% in men and 1.3% in women. Among men, 74.4% had one or more of the cardiovascular risk factors under study. Among women, 29.0% had one or more of the risk factors. With advancing age, the prevalence of risk factors became more numerous, for both men and women. CONCLUSION: In order to avert the ongoing epidemic of cerebrovascular disease and the emerging problem of ischemic heart disease, prevention and treatment of modifiable risk factors must become an important health priority in South Korea.

Adult↗

PubMed1998

Projected mortality from lung cancer in South Korea, 1980-2004.

BACKGROUND: In recent years, mortality from lung cancer has increased rapidly in Korea, a South East Asian country with a high prevalence of smoking. The objectives of this study are to examine how age, period, and birth cohort effects contributed to trends in lung cancer mortality in Korea 1980-1994, and to predict lung cancer mortality rates for 1995-2004. METHODS: Age- and sex-specific lung cancer mortality rates were obtained from annual reports of the National Office of Statistics in Korea. Poisson regression models were used to estimate age, period and cohort effects. RESULTS: Among men, age-adjusted annual mortality rates from lung cancer (per 100000) increased from 3.7 in 1980 to 17.8 in 1994; corresponding rates for women were 1.4 and 7.0. As age increased, mortality rates from lung cancer increased more rapidly in men than in women. Within the same age group, the mortality of younger cohorts was higher than older cohorts. The average annual number of lung cancer deaths projected for the years 2000-2004 among men and women will be 15441 and 3572 respectively, while the average annual age-adjusted mortality rates from lung cancer (per 100000) will be 65.4 for men and 15.1 for women. These rates correspond to 17.7- and 10.7-fold increases over the 1980 mortality rates in men and women, respectively. CONCLUSION: These results, in conjunction with trends in tobacco consumption, indicate that mortality from lung cancer in both men and women will increase substantially through the early part of the 21st century in Korea.

Adult↗

PubMed1998

MR imaging of tears of discoid lateral menisci.

OBJECTIVE: The purpose of this study was to determine the positive predictive value (PPV) for diagnosis of discoid lateral meniscal tear using MR imaging and to describe various patterns of such tears in the knee. SUBJECTS AND METHODS: MR reports of 77 patients (10-67 years old) who underwent prospective MR imaging that led to a diagnosis of discoid lateral meniscal tear were correlated with arthroscopic results. MR images obtained in 71 patients confirmed to have discoid lateral meniscial tear were retrospectively reviewed for the presence, site, and pattern of discoid lateral meniscal tear, including type of displacement of the torn segment. MR abnormalities were correlated with arthroscopic findings. RESULTS: For the prospective MR interpretations, the PPV for discoid meniscus was 92%. PPV for discoid meniscal tear was 57%. PPVs for individual types of discoid meniscal tears were 46% (peripheral tear, 19/41), 76% (peripheral tear with horizontal tears, 16/21), 56% (horizontal tear, 5/9), 50% (transverse tear, 1/2), 67% (horizontal tear combined with transverse tear, 2/3), and 100% (longitudinal tear, 1/1). Peripheral tear alone and peripheral tear with horizontal tear were the most common types of tears (n = 20, 28%). Multiple tears (n = 34, 48%) were common. Displacement of the torn segments was seen in 51 patients (72%). CONCLUSION: MR imaging has a low PPV for diagnosing discoid lateral meniscal tear. Peripheral tear alone and peripheral tear with horizontal tear were the most common types of tears, and displacement of the torn segment was frequent.

Adult↗

PubMed1998

A case of type IIa early gastric cancer developed in pernicious anemia.

Pernicious anemia is an autoimmune disease characterized by a gastric mucosal defect which results in an insufficiency of intrinsic factor to facilitate the absorption of the physiologic amount of cobalamin. Increased risk of cancers of the stomach has been reported for patients with pernicious anemia. We report here a case of a 65 year old woman who had been diagnosed as having pernicious anemia 16 months previously, was receiving monthly vitamin B12 injections, and developed early gastric cancer type IIa by routine follow-up gastroscopic examination. This patient underwent endoscopic mucosal resection for an early gastric cancer lesion with a free resection margin.

Aged↗

PubMed1998

Molecular and serologic survey of Orientia tsutsugamushi infection among field rodents in southern Cholla Province, Korea.

Field rodents were collected from six areas in southern Cholla Province, Korea from October to December 1993. Twenty-eight (24%) of the 119 Apodemus agrarius were seropositive (> 1:10) for Orientia tsutsugamushi by the passive hemagglutination assay (PHA). Of the seropositive cases, 11 specimens had antibody titers greater than 1:80. No seropositive specimens were found among the eight Crocidura lasiura collected. On the other hand, the polymerase chain reaction (PCR) amplified about 520 basepairs of a gene encoding the 56-kD protein from the genomic DNA of 12 strains of O. tsutsugamushi tested. This target DNA sequence was amplified from the 11 (8.7%) blood specimens of A. agrarius, and one of the eight C. lasiura also showed evidence of O. tsutsugamushi infection by PCR. Only one of the PCR-positive samples was also PHA-positive. These results suggest that the PCR combined with a serologic assay more accurately detects the degree of infection of rodents with rickettsiae-causing scrub typhus in epidemiologic surveys.

Animals↗

PubMed1997

T-track PCR fingerprinting for the rapid detection of genetic polymorphism.

The diversity of DNA sequences can be analyzed by comparing randomly amplified polymorphic DNA, or restriction fragment length polymorphism fragments of DNA. Such analyses are dependent on the selection of appropriate restriction enzyme(s) and/or primers. We have investigated a simpler approach to providing sensitive and specific genotyping. Cyclic extension of target sequences with dideoxythymidine generates PCR products with variable lengths. We analyzed these variable PCR products by scoring the number of variable bands and comparing the scores (numerical profiles) to establish similarities. We found that the polymorphic lengths of the PCR products were comparable among serologically defined strains. It suggests that this single PCR reaction followed by a one-step electrophoresis yields easily analyzable data that can be compared with data from other gels.

Base Sequence↗

PubMed1997

Induction of neutralizing antibody in mice by immunization with recombinant 56 kDa protein of Orientia tsutsugamushi.

Anti-oriential antibody inhibits Orientia tsutsugamushi attachment to, and penetration of, host cells. However, O. tsutsugamushi antigens that induce the production of a neutralizing antibody have not been identified. The authors immunized mice and rabbits with the recombinant 56 kDa protein of O. tsutsugamushi fused to the maltose binding protein of Escherichia coli (MBP-Bor56) and analysed their effect on O. tsutsugamushi attachment to or penetration of L929 cells. O. tsutsugamushi attachment and penetration were measured by using an indirect immunofluorescent antibody assay (IFA). O. tsutsugamushi growth in L929 cells was determined by [3H]thymidine uptake assay. By IFA, we observed a 96% reduction of attachment or penetration of O. tsutsugamushi treated with rabbit anti-MBP-Bor56 sera. [3H]thymidine uptake showed that mouse anti-MBP-Bor56 sera caused a 91% reduction in O. tsutsugamushi growth, when compared to mouse anti-MBP sera. These results suggest that the 56 kDa protein of O. tsutsugamushi plays an important role in O. tsutsugamushi attachment to or penetration of cells.

ATP-Binding Cassette Transporters↗

PubMed1997

Telomerase activity and its clinicopathological significance in gastric cancer.

In order to assess the role of telomerase in development of malignant gastric cancer, we measured the telomerase activity in gastric cancer tissues and normal tissues obtained from 95 patients by employing recently developed sensitive PCR (polymerase chain reaction)-based telomerase assay (telomeric repeat amplification protocol, TRAP). We also investigated how telomerase activity related to other clinicopathological findings including DNA ploidy and K-RAS gene point mutation. The telomerase activity was present in 85 of the 95 gastric cancer tissues, whereas we detected no telomerase activity in any normal tissue. The incidence of telomerase activity in gastric cancer tissues was not correlated to age, sex, tumour stage, histological grade, DNA ploidy or K-RAS mutation. Disease-free or overall survival of patients having tumours with detectable telomerase activity was not significantly different from that of those without telomerase activity. These findings suggest that telomerase may play a key role in the establishment and progression of the gastric cancer and further studies will be needed to elucidate the biological role of telomerase in gastric cancer.

Adult↗

PubMed1997

Antagonistic regulation of protein kinase C-induced stimulation of fibronectin synthesis by cyclic AMP in human lung fibroblasts.

We studied the interaction between cAMP and protein kinase C (PKC) signaling pathways in the regulation of fibronectin synthesis in human lung fibroblasts. Phorbol myristate acetate (PMA), a PKC activator, stimulated fibronectin synthesis and its mRNA expression in both normal and transformed human lung fibroblasts (WI-38 and WI-38 VA13, respectively). On the other hand, dibutyryl cAMP (Bt2cAMP), a cAMP analogue, did not alter fibronectin synthesis in both cell lines. The combined treatment of Bt2cAMP with PMA, however, suppressed the PMA-induced stimulation of fibronectin synthesis and mRNA expression in these cells. This study shows that cAMP pathway antagonizes PKC pathway in regulating fibronectin synthesis in human lung fibroblasts and provides an example of antagonistic interaction between cAMP and PKC signaling pathways.

Bucladesine↗

PubMed1997

Isolation of a new Orientia tsutsugamushi serotype.

Orientia tsutsugamushi, the etiological agent of scrub typhus, is an antigenically diverse organism and many serologically distinct strains have been identified. The 56 kDa protein of O. tsutsugamushi, a major protein in the outer membrane, has been thought to be responsible for this antigenic variability. A strain of O. tsutsugamushi isolated in Korea cross-reacted with both Gilliam strain-specific and Karp strain-specific monoclonal antibodies. When its 56 kDa protein gene was cloned and analyzed, its sequence showed variation especially between 1,200 and 1,250 bp, showing that this isolate is a new O. tsutsugamushi strain.

Amino Acid Sequence↗