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Park HJ, Oh Y, Kang HJ, Han EJ, Shin HY, Ahn HS, Ahn KS, Yoon BH, Han BD. A gene-specific primer extension and liquid bead array system for killer cell immunoglobulin-like receptor genotyping. ACTA ACUST UNITED AC 2011; 77:535-9. [PMID: 21395560 DOI: 10.1111/j.1399-0039.2010.01622.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Park NH, Park HJ, Park CS, Kim MS, Park SI. The emerging echogenic tract sign of pyriform sinus fistula: an early indicator in the recovery stage of acute suppurative thyroiditis. AJNR Am J Neuroradiol 2011; 32:E44-6. [PMID: 20133389 DOI: 10.3174/ajnr.a2015] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
AST is commonly associated with pyriform sinus-thyroid fistula in children. Radiologic findings of AST are documented in a few reports. We report a new sign we term the "emerging echogenic tract sign," which reflects a patent air-containing pyriform sinus-thyroid fistula on follow-up US. Recognition of this sign is an important finding suggesting an associated pyriform sinus-thyroid fistula in a patient with AST and also suggesting the adequate timing of barium esophagography to confirm the fistula.
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Lee JS, Park HK, Suh JS, Hahn WH, Kang SW, Park HJ, Kim MJ, Chung JH, Cho BS. Toll-like receptor 1 gene polymorphisms in childhood IgA nephropathy: a case-control study in the Korean population. Int J Immunogenet 2010; 38:133-8. [PMID: 21108742 DOI: 10.1111/j.1744-313x.2010.00978.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Toll-like receptors (TLRs) are innate immune mediators that stimulate nuclear factor kappa B and the inflammatory cytokines. TLR1 is expressed in renal tubular epithelial cells when the kidney is injured, but the role of TLR1 gene in glomerulonephritis has not been clearly elucidated. We aimed to investigate the association of TLR1 polymorphisms with immunoglobulin A nephropathy (IgAN) in children. One hundred and ninety pediatric patients with biopsy-proven IgAN and 283 healthy control subjects were enrolled. Two single nucleotide polymorphisms of TLR1 gene [rs4833095 (missense, Asn248Ser) and rs5743557 (promoter, -414C/T)] were selected and genotyped by direct sequencing. For rs4833095, the C/T genotype in the codominant model (vs. the T/T genotype) [odds ratio (OR) = 2.11, 95% confidence interval (CI): 1.21-3.69, P = 0.009] and the genotype containing C allele (C/T and C/C) in the dominant model (vs. the T/T genotype) (OR = 1.97, 95% CI: 1.16-3.34, P = 0.012) were associated with an increased risk of IgAN. For rs5743557, the T/T genotype in the codominant model (vs. the C/C genotype) (OR = 1.74, 95% CI: 1.02-2.96, P = 0.041) appeared to be associated with IgAN risk. In haplotype analysis, the CT haplotype revealed an association with IgAN (codominant model, OR = 1.38, 95% CI: 1.06-1.80, P = 0.017; dominant model, OR = 1.76, 95% CI: 1.16-2.67, P = 0.008). After Bonferroni correction, the association of the genotypes of rs4833095 and the CT haplotype with IgAN risk remained significant. These findings suggest that TLR1 gene polymorphisms may affect IgAN susceptibility in Korean children.
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Doyle TM, Ellis R, Park HJ, Inman MD, Sehmi R. Modulating progenitor accumulation attenuates lung angiogenesis in a mouse model of asthma. Eur Respir J 2010; 38:679-87. [PMID: 21071475 DOI: 10.1183/09031936.00133210] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Asthmatic responses are associated with the lung homing of bone marrow (BM)-derived progenitors implicated as effectors of disease pathology. Studies have shown that increases in lung extracted vascular endothelial progenitor cells (VEPCs) correlate with airway angiogenesis and declining lung function. We investigated the effect of modulating lung homing of VEPCs on tissue remodelling and airway hyperresponsiveness (AHR). BALB/c mice were sensitised to ovalbumin, subjected to a chronic exposure protocol and given early concurrent or delayed treatment with a modulator of progenitor traffic, AMD3100 (CXC chemokine receptor 4 antagonist; inhibits chemotactic activity of stromal-derived factor-1α on VEPCs). After ovalbumin challenge, early haemopoietic stem cells (HSCs) and VEPCs were enumerated along with indices of airway inflammation, lung morphometry and AHR. Following ovalbumin challenge, there was a decrease in BM and an associated increase in the lung tissue-extracted HSCs and VEPCs, together with increases in airway eosinophilia, microvessel density and AHR. These outcomes were significantly inhibited by early concurrent treatment with AMD3100. Where lung disease was established, delayed treatment with AMD3100 significantly attenuated HSC numbers and lung angiogenesis but only partially reversed sustained AHR compared with untreated ovalbumin-exposed mice. Progenitor lung homing is associated with the development of asthma pathology, and early modulation of this accumulation can prevent airway remodelling and lung dysfunction.
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Ko YG, Park HJ, Yun J, Koh PO, Min W, Cho KW, Won CK, Seong HH, Kim GS, Cho JH. DNA methylation contributes to the tissue-specific expression of the rPL-Iv gene. Placenta 2010; 31:969-75. [PMID: 20832857 DOI: 10.1016/j.placenta.2010.08.010] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/06/2010] [Revised: 08/14/2010] [Accepted: 08/17/2010] [Indexed: 10/19/2022]
Abstract
To understand the tissue-specific expression of the rat placental lactogen-I variant (rPL-Iv) gene, we investigated the methylation pattern of the 5'-flanking region of this gene in various rat tissues. We report that the 5'-flanking region of the rPL-Iv gene was hypomethylated in placenta that expressed the gene and hypermethylated in those tissues that did not express the gene. Moreover, the intron region of the rPL-Iv gene was hypomethylated in the placenta, but hypermethylated in the liver, kidney and pituitary. Although there are 5 CpG sites and the density of CpG dinucleotide is lower within 2 kb of the rPL-Iv 5'-flanking region, the methylated promoter reporter gene produced strong repression in the transcriptional activity of the gene. In addition, the 5'-flanking and intron regions of the rPL-Iv gene were hypomethylated on day 12 of gestation, and the methylation pattern in the placenta remained unchanged from mid-pregnancy until term. The entire genomic region of the rPL-Iv gene might be hypermethylated in tissues other than the placenta, within which its methylated status repress expression of the placenta-specific rPL-Iv gene. Interestingly, the methylation status of the intron region of the rPL-Iv in proliferating Rcho-1 cells was changed to the unmethylated status on day 8 and 12 of differentiation of Rcho-1 cells. These results demonstrate that demethylation in the rPL-Iv upstream region was induced at an early stage of placental development, and once the 5'-flanking region of the rPL-Iv had been demethylated, its status on the rPL-Iv genomic region was continued during pregnancy. Taken together, these results suggest that DNA methylation is responsible for the silencing of tissue-specific genes in non-expressing cells, while defined combinations of trophoblast factors dictate the expression of unmethylated rPL-Iv gene in placenta trophoblast cells.
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Ryu JC, Park HJ, Park JK, Kang KH. New electrohydrodynamic flow caused by the Onsager effect. PHYSICAL REVIEW LETTERS 2010; 104:104502. [PMID: 20366431 DOI: 10.1103/physrevlett.104.104502] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/20/2009] [Indexed: 05/29/2023]
Abstract
We report a new type of electrohydrodynamic (EHD) flow generated around a circular cylinder and a spherical particle in a dielectric liquid under dc and ac electric fields. The EHD flow is observed for various combinations of dielectric liquids and polar additives. We suggest that the EHD flow is caused by a gradient of electrical conductivity produced by a nonuniform electric field and subsequent generation of free charge in the bulk liquid. Analytical and numerical analyses which are based on the leaky-dielectric model show good agreement with experimental results.
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Jang EH, Choi JY, Park CS, Lee SK, Kim CE, Park HJ, Kang JS, Lee JW, Kang JH. Effects of green tea extract administration on the pharmacokinetics of clozapine in rats. J Pharm Pharmacol 2010; 57:311-6. [PMID: 15807986 DOI: 10.1211/0022357055687] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
Abstract
Abstract
The pharmacokinetic interaction between clozapine, an atypical antipsychotic with metabolic complications, including weight gain, and green tea consumption has not been evaluated, although green tea is responsible for beneficial effects, including weight reduction, and is widely consumed in the world. Commercial green tea extract (175 mg kg−1) or saline was administered orally for 4 days before the oral administration of clozapine (20 mg kg−1) to rats. Plasma concentrations of clozapine were measured up to 5 h after clozapine administration, and then hepatic CYP1A2 expression and activity were determined. There was no significant difference in the elimination half-life of clozapine between the green tea extract and saline groups. However, the time to reach peak concentration (Tmax) was significantly increased by green tea extract. The mean total area under the plasma concentration-time curve (AUC0-∞) and maximal peak plasma concentration (Cmax) of clozapine in the green tea extract group were significantly lower than those of controls. Green tea extract induced a ∼2-fold increase in hepatic CYP1A2 levels, while the activity increased slightly (by 10% of control). Because of this reduction in AUC and Tmax of clozapine by green tea extract pretreatment, we suggest that both the rate and amount of absorption of clozapine may be reduced by green tea extract, although the hepatic elimination phase may not be significantly altered. Therefore, the clinical implications of the effects of green tea on the bioavailability of clozapine in patients should be further evaluated.
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Jin SP, Chang MS, Shin HS, Kim BY, Park HJ, Won CH, Cho SY. Eruptive pseudo-angiomatosis lesions are associated with intravascular neutrophils and do not harbour EpsteinâBarr virus. J Eur Acad Dermatol Venereol 2010; 24:163-7. [DOI: 10.1111/j.1468-3083.2009.03370.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Lee SH, Yoo KH, Sung KW, Koo HH, Kwon YJ, Kwon MM, Park HJ, Park BK, Kim YY, Park JA, Im HJ, Seo JJ, Kang HJ, Shin HY, Ahn HS. Hepatic veno-occlusive disease in children after hematopoietic stem cell transplantation: incidence, risk factors, and outcome. Bone Marrow Transplant 2009; 45:1287-93. [PMID: 20010866 DOI: 10.1038/bmt.2009.349] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Four hundred and sixty-seven hematopoietic stem cell transplantations (HSCTs) (217 autologous and 250 allogeneic HSCT) were performed in 374 children at four pediatric HSCT centers in Korea from January 2005 to December 2007. Among 467 transplants, veno-occlusive disease (VOD) developed in 72 transplants (15.4%) at a median of 10 days after HSCT. Multivariate analysis showed that BU or TBI-containing regimen (P=0.002), VOD prophylaxis without lipo-prostaglandin E1 (PGE1) (P=0.012), number of previous HSCT (P=0.014), and pretransplant serum ferritin (P=0.018) were independent risk factors for developing VOD. Mean serum ferritin levels were significantly higher in HSCT with VOD (2109.6+/-2842.5 ng/ml) than in HSCT without VOD (1315.9+/-1094.4 ng/ml) (P<0.001). The relative risk of death within 100 days of HSCT in transplants with VOD compared with transplants without VOD was 3.39 (confidence interval: 1.78-6.45). Our results suggest that lipo-PGE1 might have a protective effect against the development of VOD, and pretransplant serum ferritin could act as a risk factor for VOD. A larger prospective study is needed to confirm a possible role of lipo-PGE1 and iron chelation therapy in reducing the incidence of VOD.
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Park B, Park HJ. Evaluation of Recursive Least Squares for the detrending of real-time fMRI. Neuroimage 2009. [DOI: 10.1016/s1053-8119(09)70577-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022] Open
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Park HJ, Cho HJ, Kim YD, Lee DW, Choi HY, Kim SM, Heo JH. Comparison of the characteristics for in-hospital and out-of-hospital ischaemic strokes. Eur J Neurol 2009; 16:582-8. [PMID: 19405202 DOI: 10.1111/j.1468-1331.2009.02538.x] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
BACKGROUND AND PURPOSE Patients who are being admitted to a hospital due to diseases other than stroke may develop a stroke (in-hospital stroke; IHS). METHODS We enrolled 111 consecutive patients who developed IHS outside a neurology ward during a 5-year period at a single hospital. The frequency, characteristics, and outcomes for IHS patients were compared with patients who develop ischaemic stroke outside of the hospital (out-of-hospital stroke; OHS). RESULTS Forty-six percent of IHS occurred in the department of cardiology or cardiovascular surgery and 60% were associated with surgery or procedures. In comparison with the OHS patient group, the IHS patient group showed an increased frequency of cardiac disease, leukocytosis, and anemia. Cardioembolism, stroke of other determined etiologies, and an incomplete evaluation were more common in the IHS group, whereas large artery atherosclerosis was more frequent in the OHS group. The IHS group had up to a 10-fold higher mortality than the OHS group, with sepsis being the most common cause of death in the IHS group. CONCLUSIONS IHS has distinct etiologies and stroke mechanisms from OHS. The prevention and management of infection could decrease mortality in IHS patients.
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Kim ST, Kim YJ, Lee JY, Lee H, Yin CS, Choi SM, Chae Y, Lee H, Park HJ. Acupuncture enhances superoxide dismutase (SOD) activity in the serum of rheumatoid arthritis patients. Clin Exp Rheumatol 2009; 27:384. [PMID: 19473588] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
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Durand DM, Park HJ, Wodlinger B. Localization and control of activity in peripheral nerves. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2009; 2008:3352-4. [PMID: 19163426 DOI: 10.1109/iembs.2008.4649923] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Interest in the field of the natural control of human limb using physiological signals has risen dramatically in the past 20 years due to the success of the brain machine interface. Cortical signals carry significant information but are difficult to access. The peripheral nerves of the body carry both command and sensory signals and are far more accessible. While numerous studies have documented the selective stimulation properties of, conventionally round, nerve cuff electrodes (i.e., transverse geometry) and even self-sizing electrodes, recording the activity levels from individual fascicles using these electrodes is still an unsolved problem. Moreover, the control algorithms for the control of joint movement with multiple contact electrodes such as the flat interface nerve electrode (FINE) have been difficult to implement. We propose solutions to both these problems by using beam forming techniques to detect the location and the activity in various fascicles. We also developed a control algorithm that separates the dynamic from the passive properties to solve the redundancy problem in multiple joint problems. This techniques could find application in the natural control of artificial limbs from peripheral nerve signals for patients with amputated limbs or to restore function in patients with stroke or paralyzed limbs.
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Durand D, Park HJ, Wodlinger B. Models of the peripheral nerves for detection and control of neural activity. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2009; 2009:3326-3329. [PMID: 19964304 DOI: 10.1109/iembs.2009.5333754] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Functional electrical stimulation (FES) can restore volitional motion of patients with neurological injuries or diseases using electrical stimulation of nerves innervating the muscles to be controlled independently. The Flat interface nerve electrode (FINE) enables the selective control of different muscles at the same time. In addition, multiple contact electrode designs allow selective recording of the various signals within the cuff. However, motion control of neuromuscular skeletal systems using multi-contact electrodes is a challenging problem due to the complexities of the systems and the large number of channels required to activate the various muscles involved in the motion. The localization and the recovery of many signals pose a significant challenge to the low signals to noise ratio and the large number of fascicles. Using computer models of the peripheral nerve, we have tested the ability of various algorithms to control the neuromuscular skeletal dynamics. Computer models have also been used to develop new methods to recover fascicular signals within the nerve. Both the control and the detection algorithms are currently being tested experimentally and preliminary results are included. The goal of this study is to develop the ability to detect nerve signals and use these signals to control joint motion in patients with stroke, amputation or paralysis.
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Kim BK, Hwang SJ, Park JB, Park HJ. Characteristics of felodipine-located poly(ε-caprolactone) microspheres. J Microencapsul 2008; 22:193-203. [PMID: 16019904 DOI: 10.1080/02652040400015346] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Felodipine-loaded poly (epsilon-caprolactone) (PCL) microspheres were prepared by two methods, the conventional emulsion solvent evapouration method and the quenching method. The aim of this work was to investigate the effects of process parameters such as emulsion type, drug loading, molecular-weight of the polymer, types of emulsion stabilizer and dispersed phase solvents, as well as preparation methods. The results show that, when conventional emulsion solvent evapouration method was used, the o/w-method produced smaller mean size and higher encapsulation efficiency compared with the o/o-method. The encapsulation efficiencies increased with an increase in the molecular weight and a decrease in crystallinity of PCL. The size of microspheres varied with the type of emulsion stabilizer used, smaller microspheres with PVA and narrow size distribution with Pol 237. The water solubility of the dispersed phase solvent was one of the critical factors in controlling the encapsulation efficiency and microsphere mean size. When water-soluble solvents such as acetonitrile and ethyl formate were used, the encapsulation efficiencies decreased due to higher evapouration rate. When quenching methods were used, in contrast to the conventional emulsion solvent evapouration method, very narrowly size-distributed but bigger microspheres were obtained.
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Desai KGH, Park HJ. Encapsulation of vitamin C in tripolyphosphate cross-linked chitosan microspheres by spray drying. J Microencapsul 2008; 22:179-92. [PMID: 16019903 DOI: 10.1080/02652040400026533] [Citation(s) in RCA: 120] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
This paper describes vitamin C-encapsulated chitosan microspheres cross-linked with tripolyphosphate (TPP) using a new process prepared by spray drying intended for oral delivery of vitamin C. Thus, prepared microspheres were evaluated by loading efficiency, particles size analysis, scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), zeta potential and in vitro release studies. The microspheres so prepared had a good sphericity and shape but varied with the volume of cross-linking agent solution added. They were positively charged. The mean particle size ranged from 6.1-9.0 microm. The size, shape, encapsulation efficiency, zeta potential and release rate were influenced by the volume of cross-linking agent. With the increasing amount of cross-linking agent, both the particle size and release rate were increased. Encapsulation efficiency decreased from 45.05-58.30% with the increasing amount of TPP solution from 10-30 ml. FTIR spectroscopy study showed that the vitamin C was found to be stable after encapsulation. XRD studies revealed that vitamin C is dispersed at the molecular level in the TPP-chitosan matrix. Well-defined change in the surface morphology was observed with the varying volume of TPP. The sphericity of chitosan microspheres was lost at higher volume of cross-linking agent. The release of vitamin C from these microspheres was sustained and affected by the volume of cross-linking agent added. The release of vitamin C from TPP-chitosan microspheres followed Fick's law of diffusion.
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Desai KGH, Park HJ. Preparation of cross-linked chitosan microspheres by spray drying: Effect of cross-linking agent on the properties of spray dried microspheres. J Microencapsul 2008; 22:377-95. [PMID: 16214786 DOI: 10.1080/02652040500100139] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Chitosan microspheres cross-linked with three different cross-linking agents viz, tripolyphosphate (TPP), formaldehyde (FA) and gluteraldehyde (GA) have been prepared by spray drying technique. The influence of these cross-linking agents on the properties of spray dried chitosan microspheres was extensively investigated. The particle size and encapsulation efficiencies of thus prepared chitosan microspheres ranged mainly between 4.1-4.7 microm and 95.12-99.17%, respectively. Surface morphology, % erosion, % water uptake and drug release properties of the spray dried chitosan microspheres was remarkably influenced by the type (chemical or ionic) and extent (1 or 2% w/w) of cross-linking agents. Spray dried chitosan microspheres cross-linked with TPP exhibited higher swelling capacity, % water uptake, % erosion and drug release rate at both the cross-linking extent (1 and 2% w/w) when compared to those cross-linked with FA and GA. The sphericity and surface smoothness of the spray dried chitosan microspheres was lost when the cross-linking extent was increased from 1 to 2% w/w. Release rate of the drug from spray dried chitosan microspheres decreased when the cross-linking extent was increased from 1 to 2% w/w. The physical state of the drug in chitosan-TPP, chitosan-FA and chitosan-GA matrices was confirmed by the X-ray diffraction (XRD) study and found that the drug remains in a crystalline state even after its encapsulation. Release of the drug from chitosan-TPP, chitosan-FA and chitosan-GA matrices followed Fick's law of diffusion.
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Desai KGH, Liu C, Park HJ. Characteristics of vitamin C immobilized particles and sodium alginate beads containing immobilized particles. J Microencapsul 2008; 22:363-76. [PMID: 16214785 DOI: 10.1080/02652040500098861] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
This paper reports the properties of vitamin C encapsulated sodium alginate beads prepared by an alternative approach. The alternative encapsulation process mainly involves immobilization of vitamin C in hydrated zinc oxide layers and encapsulation of prepared immobilized particles in sodium alginate bead. The immobilization of vitamin C in hydrated zinc oxide layers was achieved by a coprecipitation process. Fourier transform infrared (FTIR) spectroscopy showed that the vitamin C was found to be stable after its immobilization. X-ray diffraction (XRD) studies revealed that anionic vitamin C molecules are adsorbed between positively charged zinc hydroxide layers with a 1:1 layer sequence, since well-defined change in basal spacing was observed. Well-defined change in surface morphology was observed by scanning electron microscopy (SEM) when vitamin C immobilized particles are encapsulated in sodium alginate bead. The biological activity of vitamin C was retained, even after its immobilization which was confirmed by 4-dihydroxy-L-phenylalanine (L-DOPA) oxidase inhibition and free radical scavenging activity studies. The release rate of vitamin C from immobilized particles and beads was sustained through an ion exchange process. A higher amount of stable vitamin C was recovered from the bead when compared to neat vitamin C itself.
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Ko JA, Lee BH, Lee JS, Park HJ. Effect of UV-B exposure on the concentration of vitamin D2 in sliced shiitake mushroom (Lentinus edodes) and white button mushroom (Agaricus bisporus). JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2008; 56:3671-4. [PMID: 18442245 DOI: 10.1021/jf073398s] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
The aim of this study was to investigate the effect of UV-B on vitamin D 2 concentration in shiitake mushrooms and in white button mushrooms. After the exposure to UV-B, at a dose of 25 kJ/m(2), the concentration of vitamin D(2) was increased to 36.7 +/- 1.4, 68.6 +/- 4.9, and 106.4 +/- 14.7 microg/g (dry weight) for pileus, middle, and gill parts of shiitake mushroom, respectively. The gill side of whole shiitake mushrooms exposed to 0, 25, 50, and 75 kJ/m(2) increased to 2.8 +/- 0.2, 13.8 +/- 1.9, 40.7 +/- 4.4, and 61.9 +/- 10.6 microg/g (dry weight) at 25 degrees C, respectively. Irradiating slices of white button mushroom was a more efficient way of increasing the vitamin D(2) content than irradiating the gill or pileus of whole mushrooms, due to the larger exposure area. As the irradiation doses increased, the vitamin D(2) concentration also increased for both types of mushrooms. In conclusion, exposure to ultraviolet light offers an effective way of increasing the concentration of vitamin D(2) in mushrooms.
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Park HJ, Kim MJ, Ha E, Chung JH. Apoptotic effect of hesperidin through caspase3 activation in human colon cancer cells, SNU-C4. PHYTOMEDICINE : INTERNATIONAL JOURNAL OF PHYTOTHERAPY AND PHYTOPHARMACOLOGY 2008; 15:147-51. [PMID: 17897817 DOI: 10.1016/j.phymed.2007.07.061] [Citation(s) in RCA: 139] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
Hesperidin, a known flavonoid constituent of citrus, reduces the proliferation of many cancer cells. The apoptotic effects of hesperidin on human colon cancer cells, SNU-C4, were determined at concentrations of 1-100 microM. At 100 microM, hesperidin reduced cell viability to 65.00+/-0.05% of control values in a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Cell death induced by hesperidin showed apoptotic features in 4,6-diamidino-2-phenylindole (DAPI) staining and in terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) assays. Examination of the expression of apoptosis-regulating genes indicated that hesperidin treatment decreased the expression of B-cell CLL/lymphoma 2 (BCL2) mRNA, and increased the expression of BCL2-associated X protein (BAX). The expression and activity of the major apoptotic factor caspase3 (CASP3) was increased significantly with hesperidin treatment. Hesperidin down-regulated the protein expression of pro-CASP3, and up-regulated the level of active CASP3. Thus, these results suggest that hesperidin could induce apoptosis in human colon cancer cells through CASP3 activation.
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Lee S, Kim MS, Kim JS, Park HJ, Woo JS, Lee BC, Hwang SJ. Controlled delivery of a hydrophilic drug from a biodegradable microsphere system by supercritical anti-solvent precipitation technique. J Microencapsul 2007; 23:741-9. [PMID: 17123918 DOI: 10.1080/09687860600945552] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
The purpose of this study was to prepare microspheres loaded with hydrophilic drug, bupivacaine HCl using poly(D,L-lactic-co-glycolic acid) (PLGA) and poly(L-lactic acid) (PLLA). Microspheres were prepared with varying the PLGA/PLLA ratio with two different levels of bupivacaine HCl (5 and 10%) using a supercritical anti-solvent (SAS) technique. Microspheres ranging from 4-10 microm in geometric mean diameter could be prepared, with high loading efficiency. Powder X-ray diffraction (PXRD) revealed that bupivacaine HCl retained its crystalline state within the polymer and was present as a dispersion within the polymer phase after SAS processing. The release of bupivacaine HCl from biodegradable polymer microspheres was rapid up to 4 h, thereafter bupivacaine HCl was continuously and slowly released for at least 7 days according to the PLGA/PLLA ratio and the molecular weight of PLLA.
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Park HJ, Yoon SH, Zheng LT, Lee KH, Kim JW, Chung JH, Lee YA, Hong SJ. Association of the -2510A/G chemokine (C-C motif) ligand 2 polymorphism with knee osteoarthritis in a Korean population. Scand J Rheumatol 2007; 36:299-306. [PMID: 17763208 DOI: 10.1080/03009740701288165] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
OBJECTIVE To investigate the possible association between polymorphisms [the -2510A/G promoter polymorphism (rs1024611) and the Cys35Cys coding polymorphism (rs4586) in exon 2] of the chemokine (C-C motif) ligand 2 (CCL2) gene and knee osteoarthritis (OA) in a Korean population. METHODS DNA was obtained from 153 Korean primary knee OA patients and 270 healthy controls. CCL2 genomic variants (-2510A/G and Cys35Cys polymorphisms) were detected by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). In additional, the effect of -2510A/G on CCL2 transcription was examined, using a luciferase reporter gene construct transfected into HMC-1 cells. RESULTS The -2510A/G promoter polymorphism was associated with OA [genotype frequency, p = 0.041; allele frequency, p = 0.017, odds ratio (OR) = 1.45, 95% confidence interval (CI) = 1.07-1.96]. Significant association was observed between the G carrier of the -2510A/G promoter polymorphism and primary knee OA patients (p = 0.021, OR = 2.25, 95% CI = 1.12-4.52). The G carrier of the -2510A/G promoter polymorphism was also associated with both clinically subtyped OA patients (OA patients with functionally poor index and radiographically severe OA patients). However, no significant difference was found in the Cys35Cys polymorphism. Haplotype frequency analysis revealed a significant difference (chi(2) = 8.98, p = 0.030). The CCL2 serum level of subjects with the G carrier (290.0+/-87.5 pg/mL) of the -2510A/G promoter polymorphism was statistically higher than that of subjects with the non-G carrier (161.5+/-48.3 pg/mL). The luciferase activity was significantly greater from interleukin (IL)-1beta-induced cells transfected with constructs containing G at position -2510. CONCLUSIONS The G carrier of the -2510A/G promoter polymorphism was found to be associated with primary knee OA, and could be a susceptibility factor in the development of primary knee OA in the Korean population.
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Desai KG, Park HJ. Effect of manufacturing parameters on the characteristics of vitamin C encapsulated tripolyphosphate-chitosan microspheres prepared by spray-drying. J Microencapsul 2007; 23:91-103. [PMID: 16830980 DOI: 10.1080/02652040500435436] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
To prepare the sustained release vitamin C carriers, vitamin C was successfully encapsulated in tripolyphosphate (TPP) cross-linked chitosan (TPP-chitosan) microspheres by the spray-drying method at different manufacturing conditions. Manufacturing parameters (inlet temperature, liquid flow rate, chitosan concentration and volume of 1% w/v TPP solution) had a significant influence on the characteristics of thus prepared microspheres. The optimum spray-drying conditions such as inlet temperature, liquid flow rate and compressed air flow rate for the encapsulation of vitamin C in TPP-chitosan microspheres was found to be 170 degrees C, 2 ml min(-1) and 101 min(-1), respectively. The size and yield of the TPP-chitosan microspheres ranged from 3.9-7.3 microm and 54.5-67.5%, respectively. The encapsulation efficiency of TPP-chitosan microspheres ranged from 45.72-68.7% and it decreased with the increasing volume of 1% w/v TPP solution. At the same cross-linking extent, the encapsulation efficiency of TPP-chitosan microspheres increased when the concentration of chitosan was increased from 0.5-1% w/v. Effect of volume of 1% w/v TPP solution on the surface morphology of chitosan microspheres was examined by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). These studies revealed that chitosan solution (250 ml) cross-linked with 15 ml 1% w/v TPP solution produced more porous microspheres than that cross-linked with 5 and 10 ml TPP solution. The release rate of vitamin C from TPP-chitosan microspheres decreased when the concentration of chitosan was increased from 0.5-1.0% w/v. Vitamin C release rate was also modulated by varying the volume of 1% w/v TPP solution. The release rate of vitamin C from TPP-chitosan microspheres decreased with increasing volume (5-15 ml) of 1% w/v TPP solution.
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Desai KG, Liu C, Park HJ. Characteristics of vitamin C encapsulated tripolyphosphate-chitosan microspheres as affected by chitosan molecular weight. J Microencapsul 2007; 23:79-90. [PMID: 16830979 DOI: 10.1080/02652040500435360] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
In this paper, the effect of chitosan molecular weight on the characteristics (size, encapsulation efficiency, zeta potential, surface morphology and release rate) of vitamin C encapsulated tripolyphosphate cross-linked chitosan (TPP-chitosan) microspheres. The molecular weight of chitosan had a noticeable influence on the size, encapsulation efficiency, zeta potential, surface morphology and controlled release behaviour of the vitamin C encapsulated TPP-chitosan microspheres. The mean particle size and encapsulation efficiencies of TPP-chitosan microspheres were 3.1, 4.9 and 6.7 microm and 67.25, 60.43 and 52.74% for the microspheres prepared using low, medium and high molecular weight chitosan, respectively. All the TPP-chitosan microspheres (low, medium and high molecular weight) had positive charge on their surface. The zeta potential of the TPP-chitosan microspheres prepared using low, medium and high molecular weight chitosan was 41.25, 40.84 and 39.13 mV, respectively. The particle sizes of TPP-chitosan microspheres increased with increases in chitosan molecular weight. Molecular weight of chitosan did not affect significantly the % yield of TPP-chitosan microspheres prepared by spray-drying. The influence of chitosan molecular weight on the surface morphology of vitamin C encapsulated TPP-chitosan microspheres was examined by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). It was observed that, as the molecular weight of chitosan increases, TPP-chitosan microspheres with uniform spherical shape could be obtained. The physical state of vitamin C (amorphous or crystalline) in TPP-chitosan matrix was studied by X-ray diffraction (XRD) and it was found that vitamin C is dispersed at the molecular level (amorphous) in the TPP-chitosan matrix. Release rate of the vitamin C from TPP-chitosan microspheres was significantly affected by the chitosan molecular weight. The release rate decreased with increase in the chitosan molecular weight. The release of vitamin C from TPP-chitosan microspheres followed Fick's law of diffusion.
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Park HJ, Wang Z, Costa RH, Tyner A, Lau LF, Raychaudhuri P. An N-terminal inhibitory domain modulates activity of FoxM1 during cell cycle. Oncogene 2007; 27:1696-704. [PMID: 17891172 PMCID: PMC2894537 DOI: 10.1038/sj.onc.1210814] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The FoxM1 transcription factor plays critical roles in the expression of genes that are essential for cell proliferation. FoxM1 null or depleted cells fail to progress through mitosis, as expression of several mitotic genes depends upon FoxM1. The transcriptional activity of FoxM1 is stimulated by cyclin-cdk-mediated phosphorylation at a site within the transcriptional activation domain. Here, we characterize the role of an N-terminal inhibitory domain in the transcriptional activity of FoxM1. Deletion of the N-terminal 232 amino-acid residues increases the transcriptional and transforming activities of FoxM1. Moreover, while the activity of the full-length FoxM1 is stimulated by growth factors, the activity of the N-terminal deletion mutant is constitutively high in all phases of the cell cycle. The N-terminal deletion also eliminates the requirement for cyclin-cdk to activate FoxM1. We provide evidence that the N-terminal domain interacts with the C-terminal half of the transcription factor to attenuate its transcriptional activity. Moreover, the N-terminal fragment inhibits the transcriptional activity of FoxM1 in G1/S cells, but not in G2/M cells. Our results suggest that cyclin-cdk phosphorylates FoxM1 to counteract the inhibition by the N-terminal domain to fully activate FoxM1 in G2/M phase.
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