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Kim HK, Kim JW, Zilberstein A, Margolis B, Kim JG, Schlessinger J, Rhee SG. PDGF stimulation of inositol phospholipid hydrolysis requires PLC-gamma 1 phosphorylation on tyrosine residues 783 and 1254. Cell 1991; 65:435-41. [PMID: 1708307 DOI: 10.1016/0092-8674(91)90461-7] [Citation(s) in RCA: 494] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
PDGF binding to its receptor promotes the association with and stimulates the phosphorylation of PLC-gamma 1 at tyrosine and serine residues. Also, PDGF induces an increase in the hydrolysis of inositol phospholipids by PLC. How PDGF activates PLC was investigated by substituting phenylalanine for tyrosine at PLC-gamma 1 phosphorylation sites 771, 783, and 1254 and expressing the mutant enzymes in NIH 3T3 cells. Phenylalanine substitution at Tyr-783 completely blocked the activation of PLC by PDGF, whereas mutation at Try-1254 inhibited and mutation at Tyr-771 enhanced the response. Like the wild type, PLC-gamma 1 substituted with phenylalanine at Tyr-783 became associated with the PDGF receptor and underwent phosphorylation at serine residues in response to PDGF. These results suggest that PLC-gamma 1 is the PLC isozyme that mediates PDGF-induced inositol phospholipid hydrolysis, that phosphorylation on Tyr-783 is essential for PLC-gamma 1 activation. These results provide direct evidence that growth factor receptors activate the function of intracellular protein by tyrosine phosphorylation.
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Kim HK, Cheon BS, Kim YH, Kim SY, Kim HP. Effects of naturally occurring flavonoids on nitric oxide production in the macrophage cell line RAW 264.7 and their structure-activity relationships. Biochem Pharmacol 1999; 58:759-65. [PMID: 10449184 DOI: 10.1016/s0006-2952(99)00160-4] [Citation(s) in RCA: 401] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
Abstract
Flavonoids affect the inflammatory process of the mammalian system and possess anti-inflammatory as well as immunomodulatory activities in vitro and in vivo. Since nitric oxide (NO) produced by inducible nitric oxide synthase (iNOS) is one of the inflammatory mediators, the effects of various naturally occurring flavonoids on NO production in LPS-activated RAW 264.7 cells were evaluated in vitro. Flavonoids such as apigenin, wogonin, luteolin, tectorigenin, and quercetin inhibited NO production, as measured by nitrite formation at 10-100 microM. The most active among 26 flavonoid derivatives tested were apigenin, wogonin, and luteolin, having IC50 values of 23, 17, and 27 microM, respectively, while AMT, a synthetic selective iNOS inhibitor, had an IC50 value of 0.09 microM. In contrast, flavanones, such as naringenin, and flavonoid glycosides, such as apiin, did not demonstrate significant inhibition up to 100 microM. These results clearly indicated that a C-2,3 double bond might be important, and that the potency of inhibition depended upon the substitution patterns of the flavonoid molecules. The inhibitory activity of flavonoids was not due to direct inhibition of iNOS enzyme activity because they did not reasonably inhibit iNOS activity, as measured by [3H]citrulline formation from [3H]arginine, up to 100 microM. In contrast, wogonin and luteolin concentration-dependently reduced iNOS enzyme expression, when measured by western blotting, at 10-100 microM. All these results clearly demonstrated that certain flavonoids inhibit NO production in lipopolysaccharide-activated RAW 264.7 cells, and their inhibitory activity might be due to reduction of iNOS enzyme expression.
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Kundra V, Escobedo JA, Kazlauskas A, Kim HK, Rhee SG, Williams LT, Zetter BR. Regulation of chemotaxis by the platelet-derived growth factor receptor-beta. Nature 1994; 367:474-6. [PMID: 8107807 DOI: 10.1038/367474a0] [Citation(s) in RCA: 358] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Chemotaxis is an important component of wound healing, development, immunity and metastasis, yet the signalling pathways that mediate chemotaxis are poorly understood. Platelet-derived growth factor (PDGF) acts both as a mitogen and a chemoattractant. Upon stimulation, the tyrosine kinase PDGF receptor-beta (PDGFR-beta) autophosphorylates and forms a complex that includes SII2(Src homology 2)-domain-containing proteins such as the phosphatidylinositol-specific phospholipase C-gamma, Ras-GTPase-activating protein (GAP), and phosphatidylinositol-3-OH kinase. Specific tyrosine-to-phenylalanine substitutions in the PDGFR-beta can prevent binding of one SH2-domain-containing protein without affecting binding of other receptor-associated proteins. Here we use phospholipase C-gamma and PDGFR-beta mutants to map specific tyrosines involved in both positive and negative regulation of chemotaxis towards the PDGF-BB homodimer. Our results indicate that a delicate balance of migration-promoting (phospholipase C-gamma and phosphatidylinositol-3-OH kinase) and migration-suppressing (GAP) activities are recruited by the PDGFR-beta to drive chemotaxis towards PDGF-BB.
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Choi SK, Gal YS, Jin SH, Kim HK. Poly(1,6-heptadiyne)-Based Materials by Metathesis Polymerization. Chem Rev 2000; 100:1645-82. [PMID: 11749278 DOI: 10.1021/cr960080i] [Citation(s) in RCA: 341] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Kim HK, Song KS, Park YS, Kang YH, Lee YJ, Lee KR, Kim HK, Ryu KW, Bae JM, Kim S. Elevated levels of circulating platelet microparticles, VEGF, IL-6 and RANTES in patients with gastric cancer: possible role of a metastasis predictor. Eur J Cancer 2003; 39:184-91. [PMID: 12509950 DOI: 10.1016/s0959-8049(02)00596-8] [Citation(s) in RCA: 297] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
The activation of coagulation, angiogenesis and inflammatory cytokines are considered to be related with tumour growth and metastasis. We investigated the plasma levels of platelet microparticles (PMP), vascular endothelial growth factor (VEGF), IL-6, and the chemokine RANTES in patients with gastric cancer (n=109) and in healthy controls (n=29). The plasma levels of PMP, IL-6 and RANTES were significantly higher in the patients than in the healthy controls, and plasma levels of PMP, VEGF, IL-6 and RANTES were significantly higher in patients with stage IV disease than those in patients with stage I or stage II/III. In terms of predicting distant metastasis, the sensitivities of PMP, VEGF, IL-6 and RANTES were 93.3%, 56.7%, 70.0% and 81.8%, respectively, and the corresponding specificities were 91.1%, 64.6%, 79.7% and 50.0%. Among these parameters, PMP had the highest diagnostic accuracy. Significant correlations were found between PMP, VEGF, IL-6 and RANTES. This study demonstrates that the plasma levels of PMP, VEGF, IL-6 and RANTES were markedly increased in patients with stage IV disease, and that these increased plasma levels of IL-6, RANTES, and especially PMP, might be useful for identifying metastatic gastric patients.
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Wada H, Thachil J, Di Nisio M, Mathew P, Kurosawa S, Gando S, Kim HK, Nielsen JD, Dempfle CE, Levi M, Toh CH. Guidance for diagnosis and treatment of DIC from harmonization of the recommendations from three guidelines. J Thromb Haemost 2013; 11:S1538-7836(22)13716-5. [PMID: 23379279 DOI: 10.1111/jth.12155] [Citation(s) in RCA: 291] [Impact Index Per Article: 24.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Three guidelines have recently been published for the diagnosis and treatment of disseminated intravascular coagulation (DIC) in adults. This communication seeks to harmonize the recommendations in these guidelines using a modified GRADE system. The scoring system for diagnosis of DIC using global coagulation tests is known to correlate with key clinical observations and outcomes (Moderate quality). The cornerstone of DIC treatment is the treatment of the underlying condition (Moderate quality). In general, transfusion of platelets or plasma (components) in patients with DIC should be reserved for patients who are bleeding (Low quality). Therapeutic doses of heparin should be considered in cases of DIC where clinical features of thrombosis predominate. Heparin is not recommended in those patients with a high risk of bleeding, (Moderate quality). However, prophylactic doses of unfractionated heparin or low molecular we ight heparin is recommended in critically ill and non-bleeding patients with DIC for prevention of venous thromboembolism (Moderate to High quality). Although further prospective evidence from randomized controlled trials is required, administration of antithrombin or recombinant thrombomodulin may be considered in certain patients with DIC. In general, patients with DIC should not be treated with antifibrinolytic agents (Low quality). However those who present with severe bleeding, that is characterized by a markedly hyperfibrinolytic state such as leukemia (Low quality) and trauma (Moderate quality), may be treated with antifibrinolytic agents. © 2013 International Society on Thrombosis and Haemostasis.
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Kim HK, Moran ME, Salter RB. The potential for regeneration of articular cartilage in defects created by chondral shaving and subchondral abrasion. An experimental investigation in rabbits. J Bone Joint Surg Am 1991. [DOI: 10.2106/00004623-199173090-00004] [Citation(s) in RCA: 229] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/16/2023]
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He D, Wu L, Kim HK, Li H, Elmets CA, Xu H. CD8+ IL-17-producing T cells are important in effector functions for the elicitation of contact hypersensitivity responses. THE JOURNAL OF IMMUNOLOGY 2007; 177:6852-8. [PMID: 17082599 PMCID: PMC3179908 DOI: 10.4049/jimmunol.177.10.6852] [Citation(s) in RCA: 203] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Allergen-induced contact hypersensitivity (CHS) is a T cell-mediated delayed-type immune response which has been considered to be primarily mediated by CD8+ T cytotoxic type I (Tc1) cells. IFN-gamma, the prototype Tc1 (Th1) cytokine, has been implicated as the primary inflammatory cytokine for CHS. In this study, we demonstrate that neutralization of IL-17 rather than IFN-gamma suppresses the elicitation of CHS. The suppression does not result from inhibition of the proliferation of allergen-activated T cells. Allergen sensitization induces the development of distinct CD8+ T cell subpopulations that produce IFN-gamma or IL-17. Although CD8+ IL-17-producing cells are stimulated by IL-23, they are inhibited by IL-12, a prototypical stimulator of IFN-gamma-producing Tc1 cells. This indicates that CD8+ IL-17-producing cells are distinct from Tc1 cells and are important in effector functions at the elicitation of CHS. These studies provide insights into a novel mechanism for CHS.
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Research Support, N.I.H., Extramural |
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Shibata D, Hyland W, Busse P, Kim HK, Sentovich SM, Steele G, Bleday R. Immediate reconstruction of the perineal wound with gracilis muscle flaps following abdominoperineal resection and intraoperative radiation therapy for recurrent carcinoma of the rectum. Ann Surg Oncol 1999; 6:33-7. [PMID: 10030413 DOI: 10.1007/s10434-999-0033-4] [Citation(s) in RCA: 174] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
BACKGROUND Morbidity associated with a nonhealing perineal wound is the most common complication following proctectomy, particularly in the setting of recurrent carcinoma of the rectum and radiation therapy. Immediate reconstruction using the gracilis myocutaneous and muscle flaps significantly reduces the incidence of major infection associated with perineal wound closure. The purpose of this study was to assess the value of immediate reconstruction of the perineal wound using a gracilis flap in patients undergoing abdominoperineal resection and intraoperative radiation therapy. METHODS This study retrospectively reviewed our experience with immediate pelvic reconstruction using gracilis muscle flaps for patients undergoing rectal extirpation and irradiation for recurrent carcinoma of the rectum. From 1990 to 1995, 16 patients underwent abdominoperineal resection (APR) or pelvic exenteration accompanied by immediate wound closure with unilateral or bilateral gracilis muscle flaps. Morbidity and mortality outcomes were compared to those of 24 patients from our institution who, between 1988 and 1992, underwent proctectomy and irradiation for recurrent rectal carcinoma with primary closure of the perineal wound. RESULTS Major complications (i.e., major infection requiring hospitalization and/or operation) occurred in 2 (12%) of the patients with gracilis flaps versus 11 (46%) of the patients with primary closure (P = .028 by chi2 analysis for flap vs. primary closure). Minor complications (i.e., persistent sinus and subcutaneous abscess) occurred in 4 (25%) of the patients with gracilis flaps versus 5 (21%) of those with primary closure. CONCLUSION Immediate perineal reconstruction using the gracilis myocutaneous flap following proctectomy and irradiation for recurrent rectal carcinoma significantly reduces the incidence of major infection associated with perineal wound closure.
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Comparative Study |
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Jung UJ, Kim HJ, Lee JS, Lee MK, Kim HO, Park EJ, Kim HK, Jeong TS, Choi MS. Naringin supplementation lowers plasma lipids and enhances erythrocyte antioxidant enzyme activities in hypercholesterolemic subjects. Clin Nutr 2003; 22:561-8. [PMID: 14613759 DOI: 10.1016/s0261-5614(03)00059-1] [Citation(s) in RCA: 168] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
BACKGROUND AND AIMS Preliminary studies have shown that naringin has a potent lipid-lowering effect and antioxidant capacity in high-cholesterol diet fed animals. Accordingly, the present study was conducted to investigate the effect of naringin on hypercholesterolemic subjects. METHODS A hypercholesterolemic group (n=30) and healthy control group (n=30) were established based on the plasma cholesterol levels in the subjects, then all subjects received naringin (400mg/capsule/day) with regular meals for a period of 8 weeks. RESULTS In the hypercholesterolemic subjects, naringin supplementation was found to lower the plasma total cholesterol by 14% and low-density lipoprotein cholesterol concentrations by 17%, while the plasma triglyceride and high-density lipoprotein cholesterol concentrations remained unaffected. The apolipoprotein B levels in the hypercholesterolemic subjects were significantly lowered after naringin treatment, yet no change was observed in the apolipoprotein A-1 levels. The erythrocyte superoxide dismutase and catalase activities in the hypercholesterolemic group were significantly increased, whereas the glutathione peroxidase activity and plasma TBARS levels were not different from the baseline measurements. Meanwhile, naringin supplementation had no affect on plasma lipids, apolipoproteins, and TBARS levels or antioxidant enzyme activities in the control group. CONCLUSIONS Therefore, these data suggest that naringin may play an important role in lowering plasma cholesterol and regulating the antioxidant capacity in hypercholesterolemic subjects.
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Cho MY, Kim JM, Sohn JH, Kim MJ, Kim KM, Kim WH, Kim H, Kook MC, Park DY, Lee JH, Chang H, Jung ES, Kim HK, Jin SY, Choi JH, Gu MJ, Kim S, Kang MS, Cho CH, Park MI, Kang YK, Kim YW, Yoon SO, Bae HI, Joo M, Moon WS, Kang DY, Chang SJ. Current Trends of the Incidence and Pathological Diagnosis of Gastroenteropancreatic Neuroendocrine Tumors (GEP-NETs) in Korea 2000-2009: Multicenter Study. Cancer Res Treat 2012; 44:157-65. [PMID: 23091441 PMCID: PMC3467418 DOI: 10.4143/crt.2012.44.3.157] [Citation(s) in RCA: 165] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2012] [Accepted: 08/07/2012] [Indexed: 02/07/2023] Open
Abstract
Purpose As a result of various independently proposed nomenclatures and classifications, there is confusion in the diagnosis and prediction of biological behavior of gastroenteropancreatic neuroendocrine tumors (GEP-NETs). A comprehensive nationwide study is needed in order to understand the biological characteristics of GEP-NETs in Korea. Materials and Methods We collected 4,951 pathology reports from 29 hospitals in Korea between 2000 and 2009. Kaplan-Meier survival analysis was used to determine the prognostic significance of clinicopathological parameters. Results Although the GEP-NET is a relatively rare tumor in Korea, its incidence has increased during the last decade, with the most significant increase found in the rectum. The 10-year survival rate for well-differentiated endocrine tumor was 92.89%, in contrast to 85.74% in well differentiated neuroendocrine carcinoma and 34.59% in poorly differentiated neuroendocrine carcinoma. Disease related death was most common in the biliary tract (62.2%) and very rare in the rectum (5.2%). In Kaplan-Meier survival analysis, tumor location, histological classification, extent, size, mitosis, Ki-67 labeling index, synaptophysin expression, lymphovascular invasion, perineural invasion, and lymph node metastasis showed prognostic significance (p<0.05), however, chromogranin expression did not (p=0.148). The 2000 and 2010 World Health Organization (WHO) classification proposals were useful for prediction of the prognosis of GEP-NET. Conclusion The incidence of GEP-NET in Korea has shown a remarkable increase during the last decade, however, the distribution of tumors in the digestive system differs from that of western reports. Assessment of pathological parameters, including immunostaining, is crucial in understanding biological behavior of the tumor as well as predicting prognosis of patients with GEP-NET.
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Journal Article |
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Kim HK, Laor T, Horn PS, Racadio JM, Wong B, Dardzinski BJ. T2 mapping in Duchenne muscular dystrophy: distribution of disease activity and correlation with clinical assessments. Radiology 2010; 255:899-908. [PMID: 20501727 DOI: 10.1148/radiol.10091547] [Citation(s) in RCA: 161] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
PURPOSE To analyze T2 maps of pelvic and thigh muscles in Duchenne muscular dystrophy (DMD), to identify the most severely affected muscle, and to correlate the T2 of muscle with the grade of fatty infiltration at nonquantitative magnetic resonance (MR) imaging and results of clinical assessment. MATERIALS AND METHODS This prospective study was HIPAA compliant and was approved by the institutional review board; written consent was obtained from all participants' parents or guardians. Thirty-four boys with DMD (mean age, 8.4 years) were evaluated clinically (age, clinical function score, timed Gower score, time to run 30 feet, and serum creatine kinase [CK] level) and with nonquantitative MR imaging and axial T2 mapping from the iliac crest to the mid thigh. The T2 maps and mean T2 of 18 muscles in the pelvis and thighs were analyzed to identify the most severely involved muscle. The amount of fatty infiltration was assigned a grade of zero to four for all pelvic and thigh muscles by using T1-weighted nonquantitative MR images. The Spearman correlation coefficients model was used to correlate the mean T2, nonquantitative MR imaging score and clinical assessments. RESULTS The gluteus maximus muscle had the highest T2. The mean T2 for this muscle showed a significant correlation with the nonquantitative MR imaging score for fatty infiltration (P < .001) and with all clinical assessments except CK level. CONCLUSION Gluteus maximus muscles are most severely affected in patients with DMD. The T2 of the gluteus maximus muscle can be used as a quantitative and objective measure of disease severity.
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Journal Article |
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Hwang MH, Yoo JK, Kim HK, Hwang CL, Mackay K, Hemstreet O, Nichols WW, Christou DD. Validity and reliability of aortic pulse wave velocity and augmentation index determined by the new cuff-based SphygmoCor Xcel. J Hum Hypertens 2014; 28:475-81. [PMID: 24430704 DOI: 10.1038/jhh.2013.144] [Citation(s) in RCA: 149] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2013] [Revised: 10/01/2013] [Accepted: 10/23/2013] [Indexed: 11/09/2022]
Abstract
Aortic pulse wave velocity (AoPWV) and augmentation index (AIx) are commonly used measures of large elastic artery stiffness and wave reflection, respectively. Recently, a new cuff-based SphygmoCor device (Xcel) has been developed to measure both AoPWV and AIx. We sought to examine the following: (1) the validity of Xcel compared with the well-validated tonometry-based SphygmoCor device (MM3); (2) the intratest and day-to-day reliability of Xcel; (3) the influence of body side (right or left) on Xcel measurements; and (4) the relation of Xcel measurements to carotid artery compliance, distensibility and β-stiffness index. We found that measurements of AoPWV and AIx between Xcel and MM3 were not different (P=0.26 and P=0.43, N=22 and 26, respectively) and were strongly related (r=0.85 and 0.75, P<0.0001), and based on Bland-Altman plots there was good agreement between them. Intra-test (intraclass correlation=0.996 and 0.983, P<0.0001; AoPWV and AIx, N=24 and 26, respectively) and day-to-day reliability (intraclass correlation=0.979 and 0.939, P<0.0001) were high. Xcel AoPWV and AIx on the left versus right body side were not different (P=0.19 and P=0.58, N=14 and 15, respectively) and were highly correlated (r=0.99 and 0.94, P<0.0001). AoPWV and AIx measured with Xcel were positively related with β-stiffness index (r=0.62 and 0.51, P< or = 0.005, N=23 and 24, respectively) and negatively related with distensibility (r = -0.58 and -0.44, P < or = 0.02, N=23 and 24, respectively). In conclusion, Xcel measures of AIx and AoPWV are valid, highly reliable and not affected by body side. Xcel is a useful tool for use in research and the clinic.
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Validation Study |
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Lim YS, Cha MK, Kim HK, Uhm TB, Park JW, Kim K, Kim IH. Removals of hydrogen peroxide and hydroxyl radical by thiol-specific antioxidant protein as a possible role in vivo. Biochem Biophys Res Commun 1993; 192:273-80. [PMID: 8386507 DOI: 10.1006/bbrc.1993.1410] [Citation(s) in RCA: 149] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Thiol-specific antioxidant protein (Protector Protein; PRP) from Saccharomyces cerevisiae was found to remove hydrogen peroxide and hydroxyl radical in the presence of dithiothreitol (DTT). Without DTT as a reducing equivalent, the antioxidant protein did not show the activities for destroying hydrogen peroxide and hydroxyl radical. N-ethylmaleimide (NEM) was observed to prevent the PRP from both removing hydrogen peroxide and protecting the cleavage of DNA. These observations suggest that the sulfhydryl of cysteine in PRP could function as a strong nucleophile to attack and destroy H2O2 and .OH.
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Kim HK, Park TG. Microencapsulation of human growth hormone within biodegradable polyester microspheres: protein aggregation stability and incomplete release mechanism. Biotechnol Bioeng 1999; 65:659-67. [PMID: 10550772 DOI: 10.1002/(sici)1097-0290(19991220)65:6<659::aid-bit6>3.0.co;2-9] [Citation(s) in RCA: 144] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Recombinant human growth hormone (rhGH) was encapsulated within poly(D,L-lactic-co-glycolic acid) microspheres by a double emulsion solvent evaporation method. A mixture of methylene chloride and ethyl acetate in varying volume ratios was used for the microsphere preparation. Protein release profiles from three different microsphere formulations demonstrated initial burst effects ranging from 28.2% to 54.7% after a 1-day incubation and exhibited no further significant releases up to 19 days. This was because the encapsulated rhGH with the microspheres was largely aggregated in a noncovalent fashion during the formulation. Nonaggregated water soluble rhGH species within the microspheres are likely to be responsible for the rapid release upon incubation. The initially released rhGH in the incubation medium, however, was composed of mostly monomer species with a small amount of dimer as probed by size-exclusion chromatography. Circular dichroism spectra of the initially released rhGH in the medium revealed that the conformation of the released rhGH was correctly folded relative to that of native rhGH, with little variation in alpha-helix contents depending on the formulations. The "nonrelease" mechanism after the initial burst release was attributed to nonspontaneously dissociable noncovalent protein aggregation and surface adsorption of rhGH present within the microspheres.
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Lee JY, Chang C, Song HK, Moon J, Yang JK, Kim HK, Kwon ST, Suh SW. Crystal structure of NAD(+)-dependent DNA ligase: modular architecture and functional implications. EMBO J 2000; 19:1119-29. [PMID: 10698952 PMCID: PMC305650 DOI: 10.1093/emboj/19.5.1119] [Citation(s) in RCA: 140] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
DNA ligases catalyze the crucial step of joining the breaks in duplex DNA during DNA replication, repair and recombination, utilizing either ATP or NAD(+) as a cofactor. Despite the difference in cofactor specificity and limited overall sequence similarity, the two classes of DNA ligase share basically the same catalytic mechanism. In this study, the crystal structure of an NAD(+)-dependent DNA ligase from Thermus filiformis, a 667 residue multidomain protein, has been determined by the multiwavelength anomalous diffraction (MAD) method. It reveals highly modular architecture and a unique circular arrangement of its four distinct domains. It also provides clues for protein flexibility and DNA-binding sites. A model for the multidomain ligase action involving large conformational changes is proposed.
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research-article |
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Kim HK, Park SY, Lee JK, Oh TK. Gene cloning and characterization of thermostable lipase from Bacillus stearothermophilus L1. Biosci Biotechnol Biochem 1998; 62:66-71. [PMID: 9501519 DOI: 10.1271/bbb.62.66] [Citation(s) in RCA: 138] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The gene coding for an extracellular lipase of Bacillus stearothermophilus L1 was cloned in Escherichia coli. Sequence analysis showed an open reading frame of 1254 bp, which encodes a polypeptide of 417 amino acid residues. The polypeptide was composed of a signal sequence (29 amino acids) and a mature protein of 388 amino acids. An alanine replaces the first glycine in the conserved pentapeptide (Gly-X-Ser-X-Gly) around the active site serine. The expressed lipase was purified by hydrophobic interaction and ion exchange chromatography using buffers containing 0.02% (v/v) Triton X-100. The lipase was most active at 60-65 degrees C and in alkaline conditions around pH 9-10. The lipase had highest activity toward p-nitrophenyl caprylate among the synthetic substrates and tripropionin among the triglycerides. It hydrolyzed beef tallow and palm oil more rapidly than olive oil at 50 degrees C.
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Hong IK, Chung ST, Kim HK, Kim YB, Son YD, Cho ZH. Ultra fast symmetry and SIMD-based projection-backprojection (SSP) algorithm for 3-D PET image reconstruction. IEEE TRANSACTIONS ON MEDICAL IMAGING 2007; 26:789-803. [PMID: 17679330 DOI: 10.1109/tmi.2007.892644] [Citation(s) in RCA: 130] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
Remarkable progress in positron emission tomography (PET) development has occurred in recent years, in hardware, software, and computer implementation of image reconstruction. Recent development in PET scanners such as the high-resolution research tomograph (HRRT) developed by CTI (now Siemens) represents such a case and is capable of greatly enhanced resolution as well as sensitivity. In these PET scanners, the amount of coincidence line data collected contains more than 4.5 x 10(9) coincidence lines of response generated by as many nuclear detectors as 120 000. This formidable amount of data and the reconstruction of this data set pose a real problem in HRRT and have also been of the major bottle neck in further developments of high resolution PET scanners as well as their applications. In these classes of PET scanners, therefore, obtaining one set of reconstructed images often requires many hours of image reconstruction. For example, in HRRT with full data collection in a normal brain scan (using SPAN 3), the image reconstruction time is close to 80 min, making it practically impossible to attempt any list-mode-based dynamic imaging since the image reconstruction time would take many days (as much as 43 h or more for 32-frame dynamic image reconstruction). To remedy this data-handling problem in image reconstruction, we developed a new algorithm based on the symmetry properties of the projection and backprojection processes, especially in the 3-D OSEM algorithm where multiples of projection and back-projection are required. In addition, the single-instruction multiple-data (SIMD) technique also allowed us to successfully incorporate the symmetry properties mentioned above, thereby effectively reducing the total image reconstruction time to a few minutes. We refer to this technique as the symmetry and SIMD-based projection-backprojection (SSP) technique or algorithm and the details of the technique will be discussed and an example of the application of the technique to the HRRT's OSEM algorithm will be presented as a demonstration.
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Evaluation Study |
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Choi KY, Kim HK, Lee SY, Moon KH, Sim SS, Kim JW, Chung HK, Rhee SG. Molecular cloning and expression of a complementary DNA for inositol 1,4,5-trisphosphate 3-kinase. Science 1990; 248:64-6. [PMID: 2157285 DOI: 10.1126/science.2157285] [Citation(s) in RCA: 129] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
A complementary DNA (cDNA) clone that encodes inositol 1,4,5-trisphosphate 3-kinase was isolated from a rat brain cDNA expression library with the use of monoclonal antibodies. This clone had an open reading frame that would direct the synthesis of a protein consisting of 449 amino acids and with a molecular mass of 49,853 daltons. The putative protein revealed a potential calmodulin-binding site and six regions with amino acid compositions (PEST regions) common to proteins that are susceptible to calpain. Expression of the cDNA in COS cells resulted in an approximately 150-fold increase in inositol 1,4,5-trisphosphate 3-kinase activity of these cells.
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Verpoorte R, Choi YH, Kim HK. Ethnopharmacology and systems biology: a perfect holistic match. JOURNAL OF ETHNOPHARMACOLOGY 2005; 100:53-6. [PMID: 16026949 DOI: 10.1016/j.jep.2005.05.033] [Citation(s) in RCA: 129] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 05/18/2005] [Indexed: 05/03/2023]
Abstract
Traditional medical doctors often apply a holistic approach in prescribing medicines to the patient. Each individual patient gets his own optimalized medicine, usually a mixture of different ingredients. The present day paradigm of drug development of <single target, single compound>, is based on a super reductionist approach which involves mostly tests of compounds at the molecular level in, e.g., receptor binding assays. This approach is not the best for studies on traditional medicines. A more holistic approach using systems biology seems much more suited to proof efficacy and to obtain information that might lead to understanding the mode of action. Synergy, prodrugs, novel targets, all these might be detected by a systems biology approach whereas the reductioinist approach only will recognize activity on already known targets, and will not detect synergism and prodrugs. Metabolomics will be a major tool in recognizing compounds connected with activity in the traditional medicines, and will also be very useful in recognizing the effect on the test organism, which can be the patient in case of clinical trials with well established traditional medicines.
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Kim SW, Lee JI, Kim JW, Ki CS, Oh YL, Choi YL, Shin JH, Kim HK, Jang HW, Chung JH. BRAFV600E mutation analysis in fine-needle aspiration cytology specimens for evaluation of thyroid nodule: a large series in a BRAFV600E-prevalent population. J Clin Endocrinol Metab 2010; 95:3693-700. [PMID: 20501689 DOI: 10.1210/jc.2009-2795] [Citation(s) in RCA: 122] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
BACKGROUND The BRAFV600E mutation is highly specific to papillary thyroid carcinoma. A test for this mutation may increase the diagnostic accuracy of fine-needle aspiration cytology (FNAC), especially in a BRAFV600E mutation-prevalent population. METHODS This prospective study enrolled 1074 patients with thyroid nodules who underwent both FNAC and BRAFV600E mutation analysis by dual-priming oligonucleotide (DPO)-based multiplex PCR in FNA specimens. RESULTS The ancillary test for BRAFV600E significantly improved the sensitivity of FNA procedure, from 67.5% with FNAC alone to 89.6% with FNAC and the DPO-based multiplex PCR analysis combined. Diagnostic accuracy increased from 90.9 to 96.6%. Nine cases of papillary thyroid carcinoma were detected only by BRAFV600E mutation analysis. Unexpectedly, the preoperative DPO-based multiplex PCR produced five false-positive results, which surgery showed to represent benign nodules. CONCLUSIONS Molecular testing for the BRAFV600E mutation in FNA thyroid nodule specimens increases diagnostic value when applied in a BRAFV600E mutation-prevalent population. However, when using this potentially powerful technique, we must consider both its strengths and its weaknesses.
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Cha MK, Kim HK, Kim IH. Thioredoxin-linked "thiol peroxidase" from periplasmic space of Escherichia coli. J Biol Chem 1995; 270:28635-41. [PMID: 7499381 DOI: 10.1074/jbc.270.48.28635] [Citation(s) in RCA: 118] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Three different molecular masses (24, 22, and 20 kDa) of antioxidant proteins were purified in Escherichia coli. These proteins exhibited the preventive effects against the inactivation of glutamine synthetase activity and the cleavage of DNA by a metal-catalyzed oxidation system capable of generating reactive oxygen species. Their antioxidant activities were supported by a thiol-reducing equivalent such as dithiothreitol. Analysis of the amino-terminal amino acid sequences and the immunoblots between 24- and 22-kDa proteins indicates that the 24-kDa protein is an intact form of the 22-kDa protein that was previously identified 22-kDa subunit (AhpC) of E. coli alkyl hydroperoxide reductase (AhpC/AhpF). We isolated and sequenced an E. coli genomic DNA fragment that encodes 20-kDa protein. Comparison of the deduced amino acid sequence of the 20-kDa protein with that of AhpC revealed no sequence homology. A search of a data bank showed that the 20-kDa protein is a new type of antioxidant enzyme. The synthesis of this novel 20-kDa protein was increased in response to oxygen stress during growth. The 20-kDa protein resides mainly in the periplasmic space of E. coli, whereas the 24-kDa AhpC resides mainly in the matrix. The 20-kDa protein was functionally linked to the thioredoxin as an in vivo thiol-regenerating system and exerted a peroxidase activity. This 20-kDa protein is thus named "thiol peroxidase," which could act as an antioxidant enzyme removing peroxides or H2O2 within the catalase- and peroxidase-deficient periplasmic space of E. coli.
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Lee YN, Moon JH, Kim HK, Choi HJ, Choi MH, Kim DC, Lee TH, Cha SW, Cho YD, Park SH. Core biopsy needle versus standard aspiration needle for endoscopic ultrasound-guided sampling of solid pancreatic masses: a randomized parallel-group study. Endoscopy 2014; 46:1056-62. [PMID: 25098611 DOI: 10.1055/s-0034-1377558] [Citation(s) in RCA: 113] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
BACKGROUND AND STUDY AIMS An endoscopic ultrasound (EUS)-guided fine needle biopsy (EUS-FNB) device using a core biopsy needle was developed to improve diagnostic accuracy by simultaneously obtaining cytological aspirates and histological core samples. We prospectively compared the diagnostic accuracy of EUS-FNB with standard EUS-guided fine needle aspiration (EUS-FNA) in patients with solid pancreatic masses. PATIENTS AND METHODS Between January 2012 and May 2013, consecutive patients with solid pancreatic masses were prospectively enrolled and randomized to undergo EUS-FNB using a core biopsy needle or EUS-FNA using a standard aspiration needle at a single tertiary center. The specimen was analyzed by onsite cytology, Papanicolaou-stain cytology, and histology. The main outcome measure was diagnostic accuracy for malignancy. The secondary outcome measures were: the median number of passes required to establish a diagnosis, the proportion of patients in whom the diagnosis was established with each pass, and complication rates. RESULTS The overall accuracy of combining onsite cytology with Papanicolaou-stain cytology and histology was not significantly different for the FNB (n = 58) and FNA (n = 58) groups (98.3 % [95 %CI 94.9 % - 100 %] vs. 94.8 % [95 %CI 91.9 % - 100 %]; P = 0.671). Compared with FNA, FNB required a significantly lower median number of needle passes to establish a diagnosis (1.0 vs. 2.0; P < 0.001). On subgroup analysis of 111 patients with malignant lesions, the proportion of patients in whom malignancy was diagnosed on the first pass was significantly greater in the FNB group (72.7 % vs. 37.5 %; P < 0.001). CONCLUSIONS The overall accuracy of FNB and FNA in patients with solid pancreatic masses was comparable; however, fewer passes were required to establish the diagnosis of malignancy using FNB.This study was registered on the UMIN Clinical Trial Registry (UMIN000014057).
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Liang YS, Kim HK, Lefeber AWM, Erkelens C, Choi YH, Verpoorte R. Identification of phenylpropanoids in methyl jasmonate treated Brassica rapa leaves using two-dimensional nuclear magnetic resonance spectroscopy. J Chromatogr A 2006; 1112:148-55. [PMID: 16375911 DOI: 10.1016/j.chroma.2005.11.114] [Citation(s) in RCA: 103] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2005] [Revised: 10/24/2005] [Accepted: 11/29/2005] [Indexed: 11/16/2022]
Abstract
Metabolic analysis showed a clear increase in phenylpropanoid levels in Brassica rapa leaves after treatment with methyl jasmonate. A fraction of phenylpropanoids was prepared by Diaion HP-20 and Sephadex LH-20 column chromatography after MeOH-water extraction. Even with these purification steps, isolation of each phenylpropanoid for structure elucidation is not easy due to the low levels in the plants (ca. 0.004%). A mixture was analyzed without further purification using HPLC-electrospray ionization mass spectrometry and NMR spectroscopy. Based on the NMR results including (1)H NMR, J-resolved, correlated spectroscopy (COSY), heteronuclear single quantum coherence (HSQC), and heteronuclear multiple bond correlation (HMBC) spectra, both (1)H and (13)C resonances of the compounds were obtained. Using these NMR data, five phenylpropanoids conjugated with malate were identified: 5-hydroxyferuloyl-, caffeoyl-, coumaroyl-, feruloyl-, and sinapoyl malate. Of the compounds, 5-hydroxyferuloyl malate is a new phenylpropanoid. In addition to the five constitutive phenylpropanoids bearing trans-configuration, their cis forms, which are believed to be artifacts formed in the course of extraction steps, were also identified in the fraction.
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Hughes WT, Price RA, Kim HK, Coburn TP, Grigsby D, Feldman S. Pneumocystis carinii pneumonitis in children with malignancies. J Pediatr 1973; 82:404-15. [PMID: 4572932 DOI: 10.1016/s0022-3476(73)80113-1] [Citation(s) in RCA: 97] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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