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Ahn YH, Choe SB, Woo JC, Kim DS, Cundiff ST, Shacklette JM, Lim YS. Quantum interference of virtual and real amplitudes in a semiconductor exciton system. PHYSICAL REVIEW LETTERS 2002; 89:237403. [PMID: 12485041 DOI: 10.1103/physrevlett.89.237403] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/07/2002] [Indexed: 05/24/2023]
Abstract
By two-color pulse shaping, we simultaneously create virtual and real amplitudes for excitons in GaAs quantum wells, and monitor population and amplitude by pump-probe and four-wave mixing spectroscopies. Excited-state probability amplitude can be induced by the off-resonant, virtual excitations as well as by the resonant, real excitations. Population modulation in time-domain results from the interference between the virtual and real amplitudes, and the modulation depth reveals the relative contributions of these two amplitudes. The fact that virtual and real amplitudes have a phase difference of 90 degrees is demonstrated directly in time-domain.
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Yee KJ, Lee KG, Oh E, Kim DS, Lim YS. Coherent optical phonon oscillations in bulk GaN excited by far below the band gap photons. PHYSICAL REVIEW LETTERS 2002; 88:105501. [PMID: 11909367 DOI: 10.1103/physrevlett.88.105501] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/18/2001] [Indexed: 05/23/2023]
Abstract
We report on generation of coherent optical phonon oscillations in 150 microm thick bulk GaN. With photon energy far below the band gap, the generation mechanisms of coherent phonon modes of A1(LO), high- and low-frequency E2 are revealed to be the impulsive stimulated Raman scattering. We find that one among the two degenerate E2 modes is selectively detected with a proper choice of probe polarization. Dephasing times range from 1.5 to 70 ps for different modes, and phonon-three-photon absorbed carrier interactions are compared between the A1(LO) and the E2 mode.
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So HS, Oh J, Chung YT, Moon YJ, Kim DH, Moon BS, Lee HS, Baek SW, Park C, Lim YS, Kim MS, Park R. The water extract of Samultang protects the lipopolysaccharide (LPS)/phorbol 12-myristate 13-acetate (PMA)-induced damage and nitric oxide production of C6 glial cells via down-regulation of NF-kappaB. ACTA ACUST UNITED AC 2001; 34:303-10. [PMID: 11368885 DOI: 10.1016/s0306-3623(00)00073-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Samultang has been traditionally used for treatment of ischemic heart and brain diseases in oriental medicine. However, little is known about the mechanism by which Samultang rescues the myocardial and neuronal cells from ischemic damage. This study was designed to evaluate whether the water extract of Samultang may modulate the production of nitric oxide (NO) in LPS and PMA treated-C6 glial cells to protect the cells from NO-induced cytotoxicity. C6 glial cells treated with both LPS and PMA significantly produced a large amount of NO compared to untreated, PMA, or LPS-treated cells. In parallel with NO production, cotreatment of LPS and PMA induced the severe apoptotic death of C6 glial cells. However, Samultang significantly reduced both cell death and NO production by LPS/PMA in a dose-dependent manner. In addition, the modulatory effects of Samultang on LPS/PMA-induced cytotoxicity and NO production could be mimicked by exogenous treatments of N(G)MMA, a nitric oxide synthase (NOS) inhibitor, and pyrrolidine dithiocarbamate (PDTC), a strong NF-kappaB inhibitor. Treatment of C6-glial cells with LPS/PMA induced the transcriptional activation of NF-kappaB, which was markedly inhibited by Samultang. Taken together, we suggest that the protective effects of Samultang against LPS/PMA-induced cytotoxicity may be mediated by the suppression of NO synthesis via down-regulation of NF-kappaB activation.
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Lee J, Kim MS, So HS, Park C, Lim YS, Moon BS, Lee HS, Kim HJ, Park R. Protective effects of Debo on zinc-induced apoptosis of C6 glial cells via modulation of intracellular antioxidant, reduced glutathione. Immunopharmacol Immunotoxicol 2001; 23:383-96. [PMID: 11694029 DOI: 10.1081/iph-100107338] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
In the present study, the mechanical basis of a traditional herbal prescription, Debo. on cytotoxic damage of the brain cells including C6 glial and PC12 cells has been studied. Traditionally, Debo has been employed for the purpose of preventing responses to trauma, ischemia, and other diseases in the nervous system. C6 glial cells were exposed to oxidative stress through the imployment of ZnCl2, and generates H2O2 and hydroxyl radicals by fenton reaction. ZnCl2-induced death of C6 glial cells, which was revealed as apoptosis by chromatin condensation as well as DNA fragmentation. Pretreatment of Debo significantly prevented apoptotic death of C6 glial cells via inhibition of H2O, generation as well as the recovering of an antioxidant, reduced glutathione (GSH). Also, deprivation of serum and glucose, found in ischemia, deceased the viability of PC12 cells up to 60% via generation of H2O2. However, Debo significantly protected cells from ischemic damage through decrease in H2O, generation. Furthermore, Debo markedly inhibited the transcriptional activation of NF-kappaB by ZnCI, in C6 glial cells. These results suggest that Debo may function as an antioxidant system against free radicals and be applicable to protect brain cells against oxidative or ischemic stresses.
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Yee KJ, Lim YS, Dekorsy T, Kim DS. Mechanisms for the generation of coherent longitudinal-optical phonons in GaAs /AlGaAs multiple quantum wells. PHYSICAL REVIEW LETTERS 2001; 86:1630-1633. [PMID: 11290210 DOI: 10.1103/physrevlett.86.1630] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/29/2000] [Indexed: 05/23/2023]
Abstract
We show that coherent optical phonons in GaAs multiple quantum wells are generated in a completely different way as compared to bulk GaAs. Unlike in bulk GaAs where the ultrafast screening of electric fields by photogenerated charge carriers is known to be dominant, three distinctive generation mechanisms contribute simultaneously in multiple quantum wells. The interplay between impulsive Raman scattering, forbidden Raman scattering, and screening of surface electric fields, whose relative strengths are determined by laser intensity, detuning from the exciton resonance, and the barrier width, generates a rich variety of new phenomena.
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Kim HJ, Lim YS, Choi HY, Myung KB. Generalized seborrheic dermatitis in an immunodeficient newborn. Cutis 2001; 67:52-4. [PMID: 11204605] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/19/2023]
Abstract
We report the case of a female infant with failure to thrive, generalized seborrheic dermatitis, and intermittent diarrhea. Results of laboratory investigation revealed low serum immunoglobulin G IgG levels. She failed to gain additional weight and experienced recurrent infection. She died 3 months later.
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Jang KA, Lim YS, Choi JH, Sung KJ, Moon KC, Koh JK. Hypereosinophilic syndrome presenting as cutaneous necrotizing eosinophilic vasculitis and Raynaud's phenomenon complicated by digital gangrene. Br J Dermatol 2000; 143:641-4. [PMID: 10971345 DOI: 10.1111/j.1365-2133.2000.03726.x] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Cutaneous necrotizing eosinophilic vasculitis is a recently identified type of vasculitis that is characterized by an eosinophil-predominant necrotizing vasculitis affecting small dermal vessels. Clinically, it presents with pruritic erythematous and purpuric papules and plaques, peripheral eosinophilia and a good response to systemic steroid therapy. This vasculitis can be idiopathic or associated with connective tissue diseases. Although the pathogenic roles of eosinophil-derived granule proteins and interleukins have been documented in diseases associated with eosinophilia, a role of CD40 (a glycoprotein of the tumour necrosis factor receptor superfamily) has rarely been described. We describe two patients with idiopathic hypereosinophilic syndrome (HES) presenting with multiple erythematous patches and plaques on the lower extremities and Raynaud's phenomenon. They satisfied the criteria for the diagnosis of HES by clinical and laboratory investigations. Histopathology of the cutaneous lesions revealed prominent eosinophilic infiltration with local fibrinoid change in vessel walls in the dermis and subcutis. Immunohistochemical detection of CD3, CD4, CD8 and CD40 was performed. Infiltrating eosinophils were strongly stained by anti-CD40 monoclonal antibody. One patient improved with prednisolone, pentoxifylline and nifedipine, without recurrence. The other patient initially improved with steroids, but after self-withdrawal of steroid developed digital ischaemia that evolved to severe necrosis and required amputation. Cutaneous necrotizing eosinophilic vasculitis, Raynaud's phenomenon and digital gangrene may develop as cutaneous manifestations of HES. CD40 may play a part in the pathogenesis of eosinophilic vasculitis in HES.
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Lee MW, Lim YS, Choi JH, Sung KJ, Moon KC, Koh JK. Panniculitis showing membranocystic changes in the dermatomyositis. J Dermatol 1999; 26:608-10. [PMID: 10535257 DOI: 10.1111/j.1346-8138.1999.tb02057.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Clinically obvious panniculitis in association with dermatomyositis is rare. We reported a patient with panniculitis showing membranocystic changes in the dermatomyositis.
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Lim YS, Mallapur S, Kao G, Ren XC, Wadsworth WG. Netrin UNC-6 and the regulation of branching and extension of motoneuron axons from the ventral nerve cord of Caenorhabditis elegans. J Neurosci 1999; 19:7048-56. [PMID: 10436059 PMCID: PMC6782852] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/13/2023] Open
Abstract
In the Caenorhabditis elegans embryo, some ventral midline motoneurons extend a process circumferentially to the dorsal midline and a process longitudinally along ventral nerve cord interneurons. Circumferential migrations are guided by netrin UNC-6, which repels motoneuron axons dorsally. Although the motoneuron cell bodies and the longitudinal axons are positioned along UNC-6-expressing interneurons in the ventral nerve cord, the circumferential processes extend only from the motoneuron cell bodies and from defined locations along some longitudinal axons. This implies a mechanism regulates motoneuron branching of UNC-6-responsive processes. We show that expression of unc-6DeltaC, which encodes UNC-6 without domain C, partially rescues circumferential migration defects in unc-6 null animals. This activity depends on the netrin receptors UNC-5 and UNC-40. These results indicate that UNC-6DeltaC can provide the circumferential guidance functions of UNC-6. Furthermore, we show that expression of unc-6DeltaC causes motoneuron branching and the extension of processes from abnormal positions along the ventral nerve cord. This activity is also UNC-5- and UNC-40-dependent. We propose that local interactions mediated by domain C regulate motoneuron branching and responsiveness to the UNC-6 cue.
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Kang BY, Lim YS, Chung SW, Kim EJ, Kim SH, Hwang SY, Kim TS. Antigen-specific cytotoxicity and cell number of adoptively transferred T cells are efficiently maintained in vivo by re-stimulation with an antigen/interleukin-2 fusion protein. Int J Cancer 1999; 82:569-73. [PMID: 10404072 DOI: 10.1002/(sici)1097-0215(19990812)82:4<569::aid-ijc16>3.0.co;2-m] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
In order to maintain in vivo anti-tumor efficacy of antigen (Ag)-specific T cells in adoptive immunotherapy for a prolonged period, we constructed a fusion protein (OVA/IL-2) containing ovalbumin (OVA) as a model tumor Ag, co-valently linked to murine interleukin-2 (IL-2). The OVA/IL-2 protein produced in a baculovirus expression system displayed potent IL-2 bio-activity. Immunization with the OVA/IL-2 protein after adoptive transfer of OVA-specific T cells maintained the OVA-specific cytotoxicity and cell number of adoptively transferred T cells long term in vivo, while a simple mixture of recombinant OVA (rOVA) and rIL-2 did not. The response was dependent on the injection doses and times of the OVA/IL-2 protein. Furthermore, weekly re-stimulation of adoptively transferred OVA-specific T cells with the OVA/IL-2 protein cured 70% of tumor-bearing mice. In contrast, re-stimulation with a mixture of rOVA and rIL-2 could not significantly prolong the survival period of tumor-bearing mice. These studies suggest that the co-valent linkage between IL-2 and antigen confines the effect of IL-2 to antigen-specific T cells, leading to efficient maintenance of the anti-tumor activity of adoptively transferred T cells.
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Kang BY, Chung SW, Lim YS, Kim EJ, Kim SH, Hwang SY, Kim TS. Interleukin-12-secreting fibroblasts are more efficient than free recombinant interleukin-12 in inducing the persistent resistance to Mycobacterium avium complex infection. Immunology 1999; 97:474-80. [PMID: 10447770 PMCID: PMC2326848 DOI: 10.1046/j.1365-2567.1999.00796.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/1998] [Revised: 02/06/1999] [Accepted: 02/06/1999] [Indexed: 11/20/2022] Open
Abstract
To determine whether the paracrine secretion of interleukin-12 (IL-12) can efficiently stimulate the resistance to Mycobacterium avium complex (MAC) infection, 3T3 fibroblasts were stably transfected to secrete IL-12 (480 U/106 cells/48 hr) and their effect on MAC infection was investigated in genetically susceptible BALB/c mice, compared with that of free recombinant IL-12 (rIL-12). Injection with IL-12-secreting fibroblasts (3T3-IL-12) during intranasal infection with MAC resulted in a significant decrease in the bacterial load of the lung during the entire 10-week observation period, while rIL-12 reduced the bacterial load initially, at 2 weeks, but not by 10 weeks postinfection. Lung CD4+ T cells in mice injected with the 3T3-IL-12 cells showed a persistent T helper type 1 (Th1) response throughout the 10-week period. Furthermore, immunization with the 3T3-IL-12 cells induced and maintained significantly higher levels of cytotoxic activity and nitric oxide production by lung cells than did rIL-12 immunization. This work suggests that IL-12-secreting fibroblasts may serve as a vehicle for paracrine secretion of IL-12 for immunotherapy of MAC infection.
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Rider LG, Shamim E, Okada S, Pandey JP, Targoff IN, O'Hanlon TP, Kim HA, Lim YS, Han H, Song YW, Miller FW. Genetic risk and protective factors for idiopathic inflammatory myopathy in Koreans and American whites: a tale of two loci. ARTHRITIS AND RHEUMATISM 1999; 42:1285-90. [PMID: 10366124 DOI: 10.1002/1529-0131(199906)42:6<1285::aid-anr28>3.0.co;2-1] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
OBJECTIVE To better understand genetic contributions to autoimmunity, immunogenetic markers were studied in two racially discrete and geographically isolated populations of patients with idiopathic inflammatory myopathy (IIM). METHODS Clinical characteristics, as well as clinical and autoantibody subsets, were defined in 151 American white patients and 50 Korean patients with IIM. HLA-DRB1 and DQA1 genotyping was performed on patients and racially matched controls by standard molecular techniques. Gm allotypes and phenotypes were determined by the hemagglutination-inhibition method. RESULTS HLA-DRB1*0301, the linked allele DQA1*0501, and DRB1 alleles sharing the first hypervariable region motif 9EYSTS13 were major genetic risk factors for the development of myositis in whites (corrected P [Pcorr] < 0.0004, odds ratio [OR] 11.2, 4.5, and 3.1, respectively, for each factor versus controls). Although both the white and Korean patients had a similar distribution of clinical characteristics, autoantibody profiles, and clinical groups, no HLA-DRB1 nor DQA1 allele or motif was found to be a risk factor for IIM in the Korean patients. However, DRB1*14 was a protective factor in Korean patients without myositis-specific autoantibodies (Pcorr = 0.004, OR 0.046). In addition, although no Gm phenotype or allotype was identified as a risk factor in whites, Gm 21 was a protective factor for the development of IIM in Koreans (Pcorr = 0.024, OR 0.3). CONCLUSION Although myositis patients in the US and Korea share similar clinical and serologic features, the immune response genes predisposing to and protecting from myositis in each of these ethnic groups differ at two chromosomal loci. These data suggest that multiple genetic loci should be studied to identify risk and protective factors for some autoimmune diseases in various ethnic populations.
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Lim GY, Jang HS, Lee EJ, Lim YS, Jung SE, Lee JM, Park SH. Utility of the resistance index ratio in differentiating obstructive from nonobstructive hydronephrosis in children. JOURNAL OF CLINICAL ULTRASOUND : JCU 1999; 27:187-193. [PMID: 10323189 DOI: 10.1002/(sici)1097-0096(199905)27:4<187::aid-jcu4>3.0.co;2-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
PURPOSE We assessed the utility of the resistance index ratio (RIR) in distinguishing between obstructive and nonobstructive upper urinary tract dilatation in children. METHODS Twenty-three children (7 days-14 years old) with unilateral dilated collecting systems and a contralateral normal kidney were prospectively evaluated by duplex Doppler sonography. We measured the resistance index (RI) of the intrarenal arteries and calculated the RIR. Ninety-six normal kidneys in 48 controls were also evaluated. RESULTS Twelve kidneys were proved to be obstructed at the ureteropelvic junction, and 11 were found by renal scintigraphy with furosemide and/or by surgery to have nonobstructive dilatation. The mean RIR differed significantly between the obstructed and dilated nonobstructed kidneys (1.16+/-0.04 versus 1.04+/-0.04, respectively; p < 0.01). After surgical correction of ureteropelvic junction obstruction, the obstructed kidneys showed significant drops in the RIR (1.18+/-0.03 to 1.07+/-0.03, p < 0.01). The RIR showed no statistically significant relationship with age (r = -0.268, p > 0.01); however, the RI declined with increasing age (r= -0.414, p < 0.01). An RIR cut-off value of > or = 1.10 provided a good discriminatory level, resulting in a sensitivity of 92%, a specificity of 97%, a positive predictive value of 85%, and a negative predictive value of 97%. CONCLUSIONS An RIR cut-off value of > or = 1.10 appears to be an effective parameter for evaluation and follow-up of unilateral obstructive hydronephrosis in children.
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Lee MW, Jang KA, Lim YS, Choi JH, Sung KJ, Moon KC, Koh JK. Cutaneous extravascular necrotizing granuloma (Churg Strauss granuloma). Clin Exp Dermatol 1999; 24:193-5. [PMID: 10354178 DOI: 10.1046/j.1365-2230.1999.00452.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Churg Strauss granuloma (cutaneous extravascular necrotizing granuloma) is a distinct entity which is associated with systemic immunoreactive or autoimmune diseases in a majority of cases. Typically, Churg Strauss granuloma presents as symmetrical papules or nodules on the extremities. There are two histological patterns: the classic pattern reveals palisading granuloma with central degenerated collagen, interspersed polymorphonuclear leukocytes, and leukocytoclastic debris; the focal basophilic necrosis pattern does not show palisading granuloma. We report two cases of Churg Strauss granuloma with different histopathological patterns.
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Lim YS, Kang BY, Kim EJ, Kim SH, Hwang SY, Kim TS. Augmentation of therapeutic antitumor immunity by B16F10 melanoma cells transfected by interferon-gamma and allogeneic MHC class I cDNAs. Mol Cells 1998; 8:629-36. [PMID: 9856353] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/09/2023] Open
Abstract
The cDNAs for interferon-gamma (IFN-gamma) and allogeneic H-2Kd molecules were transfected into highly metastatic B16F10 melanoma cells (H-2b), and the synergistic effects of the antitumor immune responses by the doubly transfected cells (B16/Kd/IFN-gamma cells) were investigated in C57BL/6 mice (H-2b). The singly transfected B16F10 cells with either IFN-gamma or H-2Kd cDNA (B16/IFN-gamma or B16/Kd cells) were used as controls. The B16/Kd/IFN-gamma cells secreted biologically active IFN-gamma, and strongly expressed both syngeneic and allogeneic MHC class I antigens (H-2Kb and H-2Kd) on the same cell construct. Immunization with the doubly transfected B16/Kd/IFN-gamma cells induced higher anti B16F10 cellular cytotoxic responses than the single transfected B16/IFN-gamma or B16/Kd cells. Lyt-2.2 (CD8)+ T-cells were a major effector cell-type involved in the anti B16F10 responses and their cytotoxic activities were augmented in the immunized mice with the B16/Kd/IFN-gamma cells, as demonstrated by in vitro depletion experiments. The survival period of melanoma-bearing mice treated with the B16/Kd/IFN-gamma cells was significantly longer than that treated with the B16/IFN-gamma or B16/Kd cells. Furthermore, the treatment with the B16/Kd/IFN-gamma cells was capable of greatly inhibiting lung metastasis from small, established B16F10 footpad tumors. These results suggest that the augmented immunotherapeutic potentials can be achieved by the vaccination with IFN-gamma and allogeneic MHC class I genes transfected B16F10 melanoma cells.
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Lim YS, Kang BY, Kim EJ, Kim SH, Hwang SY, Kim KM, Kim TS. Vaccination with an ovalbumin/interleukin-4 fusion DNA efficiently induces Th2 cell-mediated immune responses in an ovalbumin-specific manner. Arch Pharm Res 1998; 21:537-42. [PMID: 9875491 DOI: 10.1007/bf02975371] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
To more effectively drive immune responses toward antigen-specific T helper type 2 (Th2) cell-mediated responses, we constructed a mammalian expression vector (pOVA/IL4) carrying a fused gene in which the ovalbumin (OVA) cDNA was covalently linked to murine interleukin-4 (IL-4) cDNA. A biologically active OVA/IL4 protein was expressed by the transfected COS cells with the pOVA/IL4 DNA, as demonstrated by Western blotting and cytokine bioassay. Intramuscular injection of BALB/c mice with the pOVA/IL4 DNA increased both the production of OVA-specific IL-4 by CD4+ T cells and the ratio of anti-OVA IgG1 to anti-OVA IgG2a isotypes, while the injection with the pOVA DNA alone, or with the mixture of the pOVA and pIL4 DNA did no or little increase. Furthermore, the OVA-specific, Th2 cell-mediated immune responses were significantly enhanced by multiple injections with the pOVA/IL4 DNA. These studies indicate that the direct linkage of an OVA gene to an IL-4 gene in the expression plasmid confines the effects of IL-4 to the OVA-specific cells, efficiently driving the immune response toward OVA-specific, Th2 cell-mediated responses.
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Kim SH, Yeo GS, Lim YS, Kang CD, Kim CM, Chung BS. Suppression of multidrug resistance via inhibition of heat shock factor by quercetin in MDR cells. Exp Mol Med 1998; 30:87-92. [PMID: 9873828 DOI: 10.1038/emm.1998.13] [Citation(s) in RCA: 49] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
MDR1 promoter has been shown to contain heat shock elements (HSE), and it has been reported that FM3A/M and P388/M MDR cells show a constitutively activated heat shock factor (HSF), suggesting that HSF might be an important target for reversing the multidrug resistance. Therefore, it was examined whether quercetin, which has been shown to interfere with the formation of the complex between HSE and HSF, and to downregulate the level of HSF1, can sensitize MDR cells against anticancer drugs by inhibition of HSF DNA-binding activity. In this study, quercetin appeared to inhibit the constitutive HSF DNA-binding activity and the sodium arsenite-induced HSF DNA-binding activity in the MDR cells. The basal and sodium arsenite-induced MDRCAT activities were remarkably suppressed by the treatment of quercetin. These results were well consistent with the finding that the treatment of quercetin decreased the expression level of P-gp, MDR1 gene product, in dose-dependent manner, and markedly increased the sensitivity of MDR cells to vincristine or vinblastine. These results suggest that quercetin can decrease the expression of P-gp via inhibition of HSF DNA-binding activity, and might be useful as a chemosensitizer in MDR cells.
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Lim YS, Kang BY, Kim EJ, Kim SH, Hwang SY, Kim TS. Potentiation of antigen-specific, Th1 immune responses by multiple DNA vaccination with an ovalbumin/interferon-gamma hybrid construct. Immunology 1998; 94:135-41. [PMID: 9741333 PMCID: PMC1364197 DOI: 10.1046/j.1365-2567.1998.00510.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
The preferential differentiation of T helper (Th) cells to Th1 or Th2 subsets is important with respect to susceptibility or resistance to particular infections, or to autoimmune diseases and allergic diseases. To more effectively drive immune responses toward antigen-specific Th1 responses, we constructed a mammalian expression vector (pOVA/IFN-gamma) carrying a hybrid gene in which the ovalbumin (OVA) (a model antigen) cDNA was covalently linked to murine interferon-gamma (IFN-gamma) cDNA. Intramuscular injection of BALB/c mice with the pOVA/IFN-gamma DNA increased both the production of OVA-specific IFN-gamma by CD4+ T cells and the ratio of anti-OVA immunoglobulin G (IgG) 2a to IgG1 isotypes, while the injection with the pOVA alone, or with the mixture of the pOVA and pIFN-gamma, caused no or little increase. Furthermore, the OVA-specific, Th1 immune responses were dramatically augmented by multiple injections with the pOVA/IFN-gamma DNA. These studies indicate that the direct linkage of an OVA gene to an IFN-gamma gene in the expression plasmid is required for efficiently confining the Th1 effects of IFN-gamma to the OVA-specific cells, and the linkage effect of the OVA/IFN-gamma DNA can be potentiated by multiple vaccination.
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Kang SK, Lee SO, Lim YS, Jang KL, Lee TH. Purification and characterization of a novel levanoctaose-producing levanase from Pseudomonas strain K-52. Biotechnol Appl Biochem 1998; 27:159-66. [PMID: 9569612] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Levan-assimilating micro-organisms from soil samples were screened for levanoligosaccharide-generating enzyme production. The isolated strain K-52 produced an extracellular levanoctaose-generating enzyme and was identified as belonging to genus Pseudomonas. The levanase was purified to homogeneity by (NH4)2SO4 fractionation and successive column chromatography on DEAE-cellulose, phenyl-Toyopearl 650 M, Sephadex G-100 and hydroxyapatite. The molecular mass of the enzyme was estimated as approx. 38 kDa by both SDS/PAGE and gel filtration, and its isoelectric point was approx. pH 4.8. The optimum temperature and pH for the enzyme reaction were 35 and 7.0 respectively. The enzyme was stable at a pH range of 6.0-9.0 at 4 degrees C and up to 40 degrees C at pH 6.8. The enzyme activity was inhibited by Fe2+, Cu2+, Hg2+ and Ag2+. The levanase was specific toward 2,6-beta-D-fructosidic linkages of levan and did not hydrolyse other polysaccharides such as inulin and dextran. Chemical modification on the levanase suggested that cysteine and histidine residues are essential for enzyme activity. The levanoctaose liberated by levanase reaction was used selectively only by the intestinal beneficial micro-organisms, such as Bifidobacterium and Lactobacillus spp.
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Kim SH, Hur WY, Kang CD, Lim YS, Kim DW, Chung BS. Involvement of heat shock factor in regulating transcriptional activation of MDR1 gene in multidrug-resistant cells. Cancer Lett 1997; 115:9-14. [PMID: 9097973 DOI: 10.1016/s0304-3835(97)04725-3] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The present study provides evidence that heat shock factor (HSF) may be involved in a transacting factor modulating multidrug resistance 1 (MDR1) gene. In conjunction with the presence of several heat shock elements (HSEs) in the 5' region of the MDR1 gene, we compared the level of HSF which binds to HSEs in multidrug-resistant P388/M and FM3A/M cells with that in their parental counterparts. Under unstressed condition, these multidrug-resistant cells showed constitutive HSF DNA-binding activity in the nucleus of the cells, whereas their parental counterparts did not show detectable HSF DNA-binding activity. We found that H-87, protein kinase A inhibitor, inhibited HSF DNA-binding activity in heat-shocked P388/M cells and also suppressed the levels of hsp90 and hsp70. These results demonstrated that HSF might be an important transcriptional regulator for inducing MDR1 gene, and modulation of HSF activity might be a useful potential target for reversing MDR.
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Yu PY, Su Z, Kim DS, Khim JS, Lim YS, Yee YH, Cho YH, Lee JS, Lee JH, Chang JS, Choe BD, Woo DH, Shin EJ, Kim D, Arya K, Song JJ. Probing optical-phonon propagation in GaAs/AlxGa1-xAs quantum-well samples via their nonequilibrium population. PHYSICAL REVIEW. B, CONDENSED MATTER 1996; 54:10742-10750. [PMID: 9984871 DOI: 10.1103/physrevb.54.10742] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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Moon HJ, Kim GH, Lim YS, Go CS, Lee JH, Chang JS. Lasing images from two merging ink-doped liquid droplets. OPTICS LETTERS 1996; 21:913-915. [PMID: 19876202 DOI: 10.1364/ol.21.000913] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Lasing images from two merging ink-doped ethanol droplets (size ~37 microm), which were generated by modulation techniques and pumped by nanosecond laser pulses, were photographed through a microscope. By measuring the size difference of two adjacent droplets from the spectral shifts of lasing peaks, we confirmed that mass transfer occurred in the breakup process of the liquid jet. We observed lasing images from merging droplets in a variety of patterns. Noteworthy among these is the lasing from snowman-shaped droplets that are conjectured to stem from coupled modes with orbits around both droplets.
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Go CS, Lim YS, Moon HJ, Lee JH, Chang JS. Nonlinear dispersion effects in a broadband Raman amplifier. OPTICS LETTERS 1995; 20:2366. [PMID: 19865221 DOI: 10.1364/ol.20.002366] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
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Nair S, Poh CL, Lim YS, Tay L, Goh KT. Genome fingerprinting of Salmonella typhi by pulsed-field gel electrophoresis for subtyping common phage types. Epidemiol Infect 1994; 113:391-402. [PMID: 7995349 PMCID: PMC2271314 DOI: 10.1017/s0950268800068400] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
The genomic DNA of 39 strains of Salmonella typhi isolated from local residents and patients who had visited countries in the Asian region was analysed for restriction fragment length polymorphisms (RFLP). Pulsed-field gel electrophoretic (PFGE) analysis of Xba I- and Spe I-generated genomic restriction fragments established 22 PFGE types whereas phage typing differentiated the 39 isolates into 9 distinct phage types. This study showed that PFGE is more discriminatory than phage typing as it is capable of subtyping S. typhi strains of the same phage types. Genetic relatedness among the isolates was determined. Seven major clusters were identified at SABs of > 0.80 and the remaining 13 isolates were distributed into minor clusters which were related at SABs of less than 0.80. In conclusion, PFGE analysis in conjunction with distance matrix analysis served as a useful tool for delineating common S. typhi phage types of diverse origins from different geographical locales and separated in time.
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