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McDermott MK, Saylor DM, Casas R, Dair BJ, Guo J, Kim CS, Mahoney CM, Ng K, Pollack SK, Patwardhan DV, Sweigart DA, Thomas T, Toy J, Williams CM, Witkowski CN. Microstructure and elution of tetracycline from block copolymer coatings. J Pharm Sci 2010; 99:2777-85. [PMID: 20091828 DOI: 10.1002/jps.22050] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
A critical metrology issue for pharmaceutical industries is the application of analytical techniques for the characterization of drug delivery systems to address interrelationships between processing, structure, and drug release. In this study, cast coatings were formed from solutions of poly(styrene-b-isobutylene-b-styrene) (SIBS) and tetracycline in tetrahydrofuran (THF). These coatings were characterized by several imaging modalities, including time-of-flight secondary ion mass spectrometry (TOF-SIMS) for chemical imaging and analysis, atomic force microscopy (AFM) for determination of surface structure and morphology, and laser scanning confocal microscopy (LSCM), which was used to characterize the three-dimensional structure beneath the surface. The results showed phase separation between the drug and copolymer regions. The size of the tetracycline phase in the polymer matrix ranged from hundreds of nanometers to tens of microns, depending on coating composition. The mass of drug released was not found to be proportional to drug loading, because the size and spatial distribution of the drug phase varied with drug loading and solvent evaporation rate, which in turn affected the amount of drug released.
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Park HM, Lee MH, Nahm CH, Kim WC, Lee HB, Kim CS. A case of multiple myeloma possibly cured by autologous blood stem cell transplantation. Intern Med J 2010; 40:314-5. [PMID: 20529044 DOI: 10.1111/j.1445-5994.2009.02157.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Kim CS, Vurgaftman I, Flynn RA, Kim M, Lindle JR, Bewley WW, Bussmann K, Meyer JR, Long JP. An integrated surface-plasmon source. OPTICS EXPRESS 2010; 18:10609-10615. [PMID: 20588913 DOI: 10.1364/oe.18.010609] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
A compact and versatile source of coherent surface-plasmon polaritions (SPPs) is demonstrated by end-coupling a laser diode operating at 1.46 microm to a plasmonic waveguide integrated on the same microchip. With an optimized overlap between the spatial-modes of the laser and a planar-stripe waveguide, a high coupling efficiency of approximately 36% is achieved, that computations show could approach approximately 60% with smaller, readily achievable gaps between laser and waveguide. This integrated and electrically-activated source, with an available SPP power limited only by the laser diode, appears ideally suited for directly driving plasmonic circuitry or surface-enhanced sensors.
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Kim JT, Na HS, Kim HS, Kim CS, Kim SD. CPAP of 10 cmH2O during cardiopulmonary bypass followed by an alveolar recruitment manoeuvre does not improve post-bypass oxygenation compared to a recruitment manoeuvre alone in children. Anaesth Intensive Care 2010; 38:291-4. [PMID: 20369762 DOI: 10.1177/0310057x1003800227] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
This randomised controlled study assessed whether continuous positive airway pressure (CPAP) of 10 cmH2O during cardiopulmonary bypass improves post-bypass oxygenation in children compared with no CPAP during bypass. We studied children with a ventricular septal defect. CPAP of 10 cmH2O was applied during bypass in the CPAP group (n=24), whereas the lungs were left deflated in the control group (n=20). In both groups, an alveolar recruitment maneuver was performed by applying positive pressure of 30 to 40 cmH2O for five seconds before weaning from bypass. Postoperative ventilation had the peak inflation pressure set to produce an expired tidal volume of 8 ml/kg with positive end expiratory pressure of 5 cmH2O. Arterial blood gas and haemodynamic measurements were performed at skin incision, five minutes after weaning from bypass, five minutes after chest closure and four hours after arrival in the intensive care unit. In four children CPAP was discontinued because it adversely affected the operating field. There was no difference in demographic characteristics, haemodynamic data, bypass time and operation time. No difference was observed between the groups with respect to pH, PaO2, P(A-a) DO2, PaCO2, and ETCO2 at each time. Variability in the data was greater than expected, leading to a decrease in the expected power of the study. CPAP at 10 cmH2O during bypass was not found to improve the post-bypass oxygenation as compared with leaving the lung deflated during bypass in children undergoing ventricular septal defect repair who had an alveolar recruitment maneuver at the end of bypass.
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Choi SJ, Ahn HJ, Yang MK, Kim CS, Sim WS, Kim JA, Kang JG, Kim JK, Kang JY. Comparison of desaturation and resaturation response times between transmission and reflectance pulse oximeters. Acta Anaesthesiol Scand 2010; 54:212-7. [PMID: 19719816 DOI: 10.1111/j.1399-6576.2009.02101.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
BACKGROUND In general, there is a response time between actual arterial hypoxemia and its detection by pulse oximeters. We compared the desaturation and resaturation response times between two types of pulse oximeters, transmission and reflectance pulse oximeters, to find out which oximeter has a more rapid response time. METHODS Thirty-three ASA 1 or 2 patients were enrolled in this study. A transmission pulse oximeter was placed on the index finger and a reflectance pulse oximeter was placed on the forehead and monitored simultaneously. After the induction of general anesthesia without pre-oxygenation, we waited until the oxygen saturation value of any of two pulse oximeters declined to 90%, and then mask ventilation was started with 100% oxygen. Oxygen saturation was recorded at an interval of 2 s during this time. RESULTS The desaturation response time of SpO(2) to 95% after apnea was 82.0 s (interquartile range: 67.0-98.5 s) vs. 94.0 s (interquartile range: 84.0-106.5 s) (P<0.001) and SpO(2) to 90% was 94.0 s (interquartile range: 75.5-109.5 s) vs. 100.0 s (interquartile range: 84.5-114.5 s) (P<0.001) in the reflectance and transmission oximeters, respectively. The resaturation response time from mask ventilation to 100% SpO(2) was 23.2+/-5.6 vs. 28.9+/-7.6 s (P<0.001) in the reflectance and transmission oximeters, respectively. CONCLUSION In clinical situations in which rapid changes in oxygen saturation are expected, we recommend the forehead reflectance pulse oximeter because it responds more quickly in detecting oxygen desaturation and resaturation compared with the transmission pulse oximeter.
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Kim CS, Schaible GD, Lewandrowski J, Vasavada U. Managing invasive species in the presence of endogenous technological change with uncertainty. RISK ANALYSIS : AN OFFICIAL PUBLICATION OF THE SOCIETY FOR RISK ANALYSIS 2010; 30:250-260. [PMID: 19919554 DOI: 10.1111/j.1539-6924.2009.01312.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
This research incorporates the development and adoption of an induced technology under uncertainty into a conceptual dynamic model to more broadly examine efficient policies for mitigating invasive species infestations. We find that under optimal policy, marginal costs of adopting conventional control measures are equal to the sum of the marginal benefits from development and adoption of new technology, as well as the use of conventional control measures. This result implies that a resource allocation designed for controlling invasive species is not adequate when an induced technology is not considered. Our results also reveal that the shadow values associated with the probabilities of developing and then adopting an induced technology increase as the shadow values associated with the stock of an invasive species population increase.
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Jahng D, Kim CS, Hanson RS, Wood TK. Optimization of trichloroethylene degradation using soluble methane monooxygenase of Methylosinus trichosporium OB3b expressed in recombinant bacteria. Biotechnol Bioeng 2009; 51:349-59. [PMID: 18624367 DOI: 10.1002/(sici)1097-0290(19960805)51:3<349::aid-bit10>3.0.co;2-h] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
By complementing cell-free extracts of Pseudomonas putida F1/pSMMO20 with purified soluble methane monooxygenase (sMMO) components of Methylosinus trichosporium OB3b, the low cloned-gene sMMO activity in the recombinant strain was found to be due to incomplete activity of the hydroxylase component. To address this incomplete activity, additional sMMO-expressing strains were formed by transferring mmo-containing pSMMO20 and pSMMO50 into various bacterial species including pseudomonads and alpha-2 subdivision strains such as methanotrophs, methylotrophs, Agrobacterium tumefaciens A114, and Rhizobium meliloti 102F34 (11 new strains screened); sMMO activity was detected in the last two strains. To increase plasmid segregational stability, the hok/sok locus originally from Escherichia coli plasmid R1 was inserted downstream of the mmo locus of pSMMO20 (resulting in pSMMO40) and found to enhance plasmid stability in P. putida F1 and R. meliloti 102F34 (first report of hok/sok in Rhizobium). To further increase sMMO activity, a modified Whittenbury minimal medium was selected from various minimal and complex media based on trichloroethylene (TCE) degradation and growth rates and was improved by removing the sMMO-inhibiting metal ions [Cu(II), Ni(II), and Zn(II)] and chloramphenicol from the medium and by supplementing with an iron source (3.6 microM of ferrous ammonium sulfate). Using chemostat-grown P. putida F1/pSMMO40, it was found that sMMO activity was higher for cells grown at higher dilution rates. These optimization efforts resulted in a twofold increase in the extent of TCE degradation and more consistent sMMO activity.
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Kim CS, Saylor DM, McDermott MK, Patwardhan DV, Warren JA. Modeling solvent evaporation during the manufacture of controlled drug-release coatings and the impact on release kinetics. J Biomed Mater Res B Appl Biomater 2009; 90:688-99. [DOI: 10.1002/jbm.b.31336] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Saylor DM, Kim CS, Patwardhan DV, Warren JA. Modeling microstructure development and release kinetics in controlled drug release coatings. J Pharm Sci 2009; 98:169-86. [PMID: 18481310 DOI: 10.1002/jps.21416] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
In recent years, controlled release coatings, comprised of drug-polymer composites, have been integrated with medical devices, improving device functionality and performance. However, relationships between material properties, manufacturing environment, composite (micro)structure, and subsequent release kinetics are not well established. We apply a thermodynamically consistent model to probe the influence of drug-polymer chemistry (phobicity), drug loading, and evaporation rate on microstructure development during fabrication. For these structures, we compute release profiles for exposure to polymer-insoluble media and media in which the polymer readily dissolves. We find that with increasing drug-polymer phobicity, structural heterogeneities form at lower loadings and more rapid rates. The heterogeneities remain isolated and compact at low loadings and become interconnected as the drug to polymer ratio approaches 1.0. Release into polymer-insoluble media was dramatically enhanced by heterogeneities, resulting in up to a fourfold increase in drug release. In polymer-soluble media, however, heterogeneities diminished release. Although reductions of only 30% were typically observed, the absolute changes were much larger than observed in polymer-insoluble media. Our results suggest that improved comprehension and quantification of the physico-chemical properties in controlled release systems will enable the microstructure to be tailored to achieve desired responses that are insensitive to manufacturing variations.
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Na HS, Kim JT, Kim HS, Bahk JH, Kim CS, Kim SD. Practical anatomic landmarks for determining the insertion depth of central venous catheter in paediatric patients. Br J Anaesth 2009; 102:820-3. [PMID: 19380312 DOI: 10.1093/bja/aep078] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
BACKGROUND Various methods have been recommended to decide a proper insertion depth of central venous catheter (CVC). The carina is recommended as a useful target level for the CVC tip position. We evaluated the sternal head of a right clavicle and the nipples as anatomic landmarks for determining the optimal depth of CVC in paediatric patients. METHODS Ninety children, <5 yr, undergoing catheterization through the right internal jugular vein were enrolled. The insertion depth was determined as follows. The insertion point was designated as 'Point I'. The sternal head of the right clavicle was called 'Point A' and the midpoint of the perpendicular line drawn from Point A to the line connecting both nipples was called 'Point B'. The insertion depth of CVC was determined by adding the two distances (from I to A and from A to B) and subtracting 0.5 cm from this. A chest radiography was taken and the distance of the CVC tip from the carina level was measured by the Picture Archiving and Communicating System. RESULTS The mean distance of the CVC tip from the carina level was 0.1 (1.0) (P=0.293) cm above the carina (95% CI 0.1 cm below the carina-0.3 cm above the carina). There was no specific relationship between the distance of the CVC tip from the carina level and the patients' age, height, and weight. CONCLUSIONS The CVC tip could be placed near the carina by using the external landmarks without any formulae, images, and devices in children in our study.
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Sekhon SS, Park JS, Cho E, Yoon YG, Kim CS, Lee WY. Morphology Studies of High Temperature Proton Conducting Membranes Containing Hydrophilic/Hydrophobic Ionic Liquids. Macromolecules 2009. [DOI: 10.1021/ma8027112] [Citation(s) in RCA: 83] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Ambekar R, Park J, Henthorn DB, Kim CS. Photopatternable Polymeric Membranes for Optical Oxygen Sensors. IEEE SENSORS JOURNAL 2009; 9:169-175. [PMID: 19554206 PMCID: PMC2701202 DOI: 10.1109/jsen.2008.2011069] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
A new class of optical oxygen sensor that can be photopatternable by traditional UV lithography is presented. They are fabricated using photopatternable spin-on silicone (polydimethyl-siloxane, PDMS) with oxygen sensitive luminescent dyes. It has a good adhesion property and can be applied on glass or on photopolymer (SU-8) without any additional surface treatments. The optimum mixture composition for patternable oxygen sensitive membranes is investigated and its optical properties are characterized. Proof-of-concepts for two applications, intensity-based oxygen sensing with SU-8 based structure and self-calibration fluidic oxygen sensor, are described. These photopatternable optical membranes will find many applications wherever small patterns of oxygen sensitive membranes are required.
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Kim YK, Kim CS, Han YM. Detection of small hepatocellular carcinoma: comparison of conventional gadolinium-enhanced MRI with gadolinium-enhanced MRI after the administration of ferucarbotran. Br J Radiol 2009; 82:468-84. [PMID: 19124563 DOI: 10.1259/bjr/76535286] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
We compared the diagnostic efficacy of gadolinium (Gd)-enhanced MRI with that of Gd-enhanced MRI after administration of ferucarbotran for revealing small hypervascular hepatocellular carcinomas (HCCs). 24 patients with 34 HCCs (ranging in size from 0.6-2.0 cm) underwent Gd-enhanced three-dimensional dynamic MRI followed, after an interval of 5-11 days (mean, 7 days), by Gd-enhanced three-dimensional dynamic MRI after administration of ferucarbotran. The two Gd-enhanced arterial-phase MRI scans were compared quantitatively by measuring the tumour-liver contrast-to-noise ratio (CNR) and qualitatively by evaluating the tumour-liver contrast using matched-pairs analysis. The tumour-liver CNR with Gd-enhanced arterial-phase imaging after ferucarbotran (250.3 +/- 103.7) was higher than that with Gd-enhanced arterial-phase imaging (221.1 +/- 96.1) (p < 0.001). Matched-pairs analysis indicated that, for three lesions, the relative tumour-liver contrast was slightly better with Gd-enhanced arterial-phase imaging after ferucarbotran than with conventional Gd-enhanced arterial-phase imaging; however, in the case of the remaining 31 lesions, the two images were equivalent. We concluded that, although Gd-enhanced arterial-phase imaging after ferucarbotran results in better tumour-liver CNR than Gd-enhanced arterial-phase imaging, the ability of the two techniques to reveal small hypervascular HCCs is the same.
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Kim JT, Na HS, Bae JY, Kim DW, Kim HS, Kim CS, Kim SD. GlideScope video laryngoscope: a randomized clinical trial in 203 paediatric patients. Br J Anaesth 2008; 101:531-4. [PMID: 18689807 DOI: 10.1093/bja/aen234] [Citation(s) in RCA: 113] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND The GlideScope intubating device has been reported to provide a comparable or superior laryngoscopic view compared with direct laryngoscopy in adults. This study compared the use of the GlideScope with direct laryngoscopy for the laryngoscopic view and intubation time in children. METHODS The laryngoscopic view in 203 children was scored using both the Macintosh laryngoscope and the GlideScope using Cormack and Lehane (C&L) grades. After scoring each laryngoscopic view with and without BURP, the patients were randomly allocated to two groups. The trachea was intubated using direct laryngoscopy (Group DL, n=100) or the GlideScope (Group GS, n=103). We compared C&L grades for the two views in the same patient, and also the time to intubate for each group. RESULTS The GlideScope improved the view without BURP in the patients with C&L grade 2 (16/26, P<0.01) and with C&L grades 3 and 4 (7/11, P<0.05). The view with BURP was also improved by the GlideScope in C&L grade 2 (4/9, P<0.05) and with C&L grades 3 and 4 (4/5, P=0.059). The mean time for tracheal intubation was 36.0 (17.9) s in the GS group and 23.8 (13.9) s in the DL group (P<0.001). CONCLUSIONS In children, the GlideScope provided a laryngoscopic view equal to or better than that of direct laryngoscopy but required a longer time for intubation.
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Pirollo KF, Rait A, Zhou Q, Zhang XQ, Zhou J, Kim CS, Benedict WF, Chang EH. Tumor-targeting nanocomplex delivery of novel tumor suppressor RB94 chemosensitizes bladder carcinoma cells in vitro and in vivo. Clin Cancer Res 2008; 14:2190-8. [PMID: 18381961 DOI: 10.1158/1078-0432.ccr-07-1951] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
PURPOSE RB94, a truncated form of RB110, has enhanced tumor suppressor potency and activity against all tumor types tested to date including bladder carcinoma. However, efficient, systemic delivery of the gene encoding RB94 specifically to tumors, is an obstacle to clinical application as an anticancer therapeutic. We have developed a systemically given, nanosized liposome DNA delivery system that specifically targets primary and metastatic disease. The ability of RB94, delivered via this nanocomplex, to sensitize bladder carcinoma to chemotherapy in vitro and in vivo was assessed. EXPERIMENTAL DESIGN The nanocomplex is an RB94 plasmid encapsulated by a cationic liposome, the surface of which is decorated with a tumor-targeting moiety, either transferrin (Tf/Lip/RB94) or an antitransferrin receptor single-chain antibody fragment (TfRScFv/Lip/RB94). The ability of the complex to sensitize human bladder carcinoma HTB-9 cells to chemotherapeutics was assessed in vitro by XTT assay. In vivo tumor specificity and efficacy were tested in mice carrying HTB-9 tumors by PCR and tumor growth inhibition, respectively. RESULTS Transfection with Tf/Lip/RB94 significantly sensitized HTB-9 cells to chemotherapeutic agents in vitro. Tumor specificity of the complex was shown in an orthotopic bladder tumor model by immunohistochemistry and PCR. Moreover, in mice bearing subcutaneous HTB-9 tumors, the combination of systemically given Tf/Lip/RB94 or TfRScFv/Lip/RB94 plus gemcitabine resulted in significant (P<0.0005) tumor growth inhibition/regression and induction of apoptosis. CONCLUSIONS Use of our tumor-targeting nanocomplex to specifically deliver the potent tumor suppressor RB94 efficiently to tumors has potential as a more effective treatment modality for genitourinary and other cancers.
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Kim CS, Lee SC, Kim YM, Kim BS, Choi HS, Kawada T, Kwon BS, Yu R. Visceral fat accumulation induced by a high-fat diet causes the atrophy of mesenteric lymph nodes in obese mice. Obesity (Silver Spring) 2008; 16:1261-9. [PMID: 18369345 DOI: 10.1038/oby.2008.55] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
OBJECTIVE A high intake of fat in the diet plays a crucial role in promoting obesity and obesity-related pathologies, and especially visceral obesity is closely associated with obesity-related complications. Because adipose tissue is anatomically associated with lymph nodes, the secondary lymphoid organ, we hypothesized that fat tissue-derived factors may influence the cellularity of lymphoid tissue embedded in fat. METHODS AND PROCEDURES Mesenteric and inguinal lymph nodes were isolated from obese mice fed a high-fat diet and control mice fed a regular diet. T-cell population, activation state, and the extent of apoptosis were determined by flow cytometric analysis or terminal deoxynucleotidyl transferase biotin-dUTP nick end labeling (TUNEL) assay. RESULTS The weight of mesenteric lymph nodes and the total number of lymphoid cells in the obese mice significantly decreased compared with those in the control mice; however, no change was observed in the weight of inguinal lymph nodes. The numbers of CD4(+) and CD8(+) T cells in the mesenteric lymph nodes of obese mice significantly decreased compared with those of the control. Enhanced T-cell activation and apoptosis were observed in the mesenteric lymph node cells of the obese mice. The treatment of lymph node cells with free fatty acids, oxidative stress, and chylomicrons, which are obesity-related factors, resulted in lymph node T-cell activation and apoptosis. DISCUSSION These results suggest that visceral fat accumulation with a high-fat diet can cause the atrophy of mesenteric lymph nodes by enhancing activation-induced lymphoid cell apoptosis. Dietary fat-induced visceral obesity may be crucial for obesity-related immune dysfunction.
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Choi K, Kim Y, Jung J, Kim MH, Kim CS, Kim NH, Park J. Occurrences and ecological risks of roxithromycin, trimethoprim, and chloramphenicol in the Han River, Korea. ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY 2008; 27:711-9. [PMID: 17944547 DOI: 10.1897/07-143.1] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/20/2007] [Accepted: 08/22/2007] [Indexed: 05/24/2023]
Abstract
We evaluated the occurrence of three antibiotics (roxithromycin, trimethoprim, and chloramphenicol) in surface water and effluents from several sewage treatment plants (STPs) on the Han River, Korea. In addition, standard acute toxicity tests were conducted using the microbe Vibrio fischeri, freshwater macroinvertebrates Daphnia magna and Moina macrocopa, and fish (Oryzias latipes) for these antibiotics. Antibiotics were more frequently detected at higher amounts in effluent samples and in samples collected during the low-flow season. For trimethoprim and chloramphenicol, the levels observed in surface water during low flow were, on average, 108 and 31 ng/L, respectively. These levels were comparable to those measured in the municipal effluents (average, 80 and 37 ng/L, respectively), suggesting the presence of other sources upstream (e.g., livestock wastes). For roxithromycin, surface water levels were approximately an order of magnitude lower than effluent levels. Adverse effects of roxithromycin, trimethoprim, and chloramphenicol were observed at mg/L levels in standard acute aquatic ecotoxicity tests. Based on hazard quotients calculated for the three antibiotics, minimal risks to aquatic systems are suggested. To further increase scientific understanding about the potential impacts of these pharmaceuticals in the environment, however, chronic ecotoxicology studies, with more subtle but ecologically meaningful end points or in combination with other mechanistically related contaminants, may be beneficial.
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Kim KO, Choe G, Chung SH, Kim CS. Delayed pharmacological pre-conditioning effect of mitochondrial ATP-sensitive potassium channel opener on neurologic injury in a rabbit model of spinal cord ischemia. Acta Anaesthesiol Scand 2008; 52:236-42. [PMID: 18005376 DOI: 10.1111/j.1399-6576.2007.01534.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
BACKGROUND Diazoxide, pharmacological openers of mitochondrial ATP-sensitive potassium channels have been shown to induce early pre-conditioning in the spinal cord. Here, the authors investigated whether diazoxide also induce delayed pre-conditioning and thereby reduce neurologic complications using a rabbit model of spinal cord ischemia. METHODS Infrarenal blood flow was interrupted for 20 min in 21 rabbits. Non-treated control animals received no pre-treatment. Diazoxide (5 mg/kg) were given 48 h before 20 min ischemia in the 48-h DZ group, whereas 15-min DZ group received diazoxide (5 mg/kg) 15 min before 20-min ischemia. Neurological functions were evaluated using Johnson scores for 3 days after reperfusion, after which, spinal cords were procured for hematoxylin and eosin staining for cell counting. RESULTS Johnson scores revealed a marked improvement in both the diazoxide-treated groups vs. the non-treated control group at 3, 24, 48, and 72 h after reperfusion (P<0.01). The histologic changes were proportional to the Johnson scores, with better preservation of motor neuron numbers in the animals of the 48-h DZ and 15-min DZ group relative to the non-treated controls (81+/-12, 90+/-10, 50+/-23 motor neurons, respectively, P<0.01). No difference was found between the 48-h DZ group and 15-min DZ group with respect to the Johnson scores or neuron numbers. CONCLUSIONS The study demonstrates that pre-treatment with diazoxide 48 h before ischemia, induce delayed pharmacological pre-conditioning, thereby significantly improving clinical neurologic scores and histologic findings in this animal model.
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Badalyan SM, Kim CS, Vignale G. Finite width and local field corrections to spin coulomb drag in a quasi-two-dimensional electron gas. PHYSICAL REVIEW LETTERS 2008; 100:016603. [PMID: 18232799 DOI: 10.1103/physrevlett.100.016603] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/11/2007] [Indexed: 05/25/2023]
Abstract
We study the spin Coulomb drag in a quasi-two-dimensional electron gas of finite transverse width, including local field corrections beyond the random phase approximation (RPA). We find that the finite transverse width of the electron gas causes a significant reduction of the spin Coulomb drag. This reduction, however, is largely compensated by the enhancement coming from the inclusion of many-body local field effects beyond the RPA, thereby restoring good agreement with the experimental observations by C. P. Weber et al. [Nature (London) 437, 1330 (2005)].
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Gao Z, Henthorn DB, Kim CS. Enhanced wettability of SU-8 photoresist through a photografting procedure for bioanalytical device applications. JOURNAL OF MICROMECHANICS AND MICROENGINEERING : STRUCTURES, DEVICES, AND SYSTEMS 2008; 18:450131-450137. [PMID: 19756177 PMCID: PMC2743514 DOI: 10.1088/0960-1317/18/4/045013] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
In this work, we detail a method whereby a polymeric hydrogel layer is grafted to the negative tone photoresist SU-8 in order to improve its wettability. A photoinitiator is first immobilized on freshly prepared SU-8 samples, acting as the starting point for various surface modifications strategies. Grafting of a 2-hydroxyethylmethacrylate-based hydrogel from the SU-8 surface resulted in the reduction of the static contact angle of a water droplet from 79 +/- 1 degrees to 36 +/- 1 degrees , while addition of a poly(ethylene glycol)-rich hydrogel layer resulted in further improvement (8 +/- 1 degrees ). Wettability is greatly enhanced after 30 minutes of polymerization, with a continued but more gradual decrease in contact angle up to approximately 50 minutes. Hydrogel formation is triggered by exposure to UV irradiation, allowing for the formation of photopatterned structures using existing photolithographic techniques.
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Park JS, Park SH, Park GG, Lee WY, Kim CS, Moon SH. Determination of Properties of Ionomer Binder Using a Porous Plug Model for Preparation of Electrodes of Membrane-Electrode Assemblies for Polymer Electrolyte Fuel Cells. JOURNAL OF THE KOREAN ELECTROCHEMICAL SOCIETY 2007. [DOI: 10.5229/jkes.2007.10.4.295] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Ahn EJ, Park GG, Yoon YG, Park JS, Lee WY, Kim CS. Effect of Clamping Pressure on Surface Properties of Gas Diffusion Layer in PEFCs. JOURNAL OF THE KOREAN ELECTROCHEMICAL SOCIETY 2007. [DOI: 10.5229/jkes.2007.10.4.306] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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123
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Kim JT, Jeon SY, Kim CS, Kim SD, Kim HS. Alternative method for predicting optimal insertion depth of the laryngeal tube in children. Br J Anaesth 2007; 99:704-7. [PMID: 17724391 DOI: 10.1093/bja/aem241] [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: 11/13/2022] Open
Abstract
BACKGROUND Little information is available about the accuracy of the teeth mark on the laryngeal tube (LT) as a guide to correct placement in children. The aim of this crossover study was to evaluate three methods for optimal insertion depth of the size (#) 2 tube in children weighing 12-25 kg. METHOD In 24 children, the LT #2 was consecutively inserted by three different methods: (A) until the thick teeth mark on the tube was aligned with the upper incisors, (B) until resistance was felt, and (C) by inserting to a depth, previously measured, of the curved distance between the cricoid cartilage and the upper incisor. In each case, the depth of insertion, the degree of effective ventilation, the presence of leakage, and the fibreoptic view were assessed. RESULTS Insertion based on the teeth mark led to a shorter insertion depth and a greater incidence of inadequate ventilation compared with the other two methods. There was no difference in the adequacy of ventilation between methods B and C. The vocal cords were more easily identified with methods B (62.5%) and C (75%) than with method A (12.5%). CONCLUSIONS Insertion of the LT #2 aligned with the teeth mark can result in a shallow insertion depth and inadequate ventilation. The measured distance from the cricoid cartilage to the upper incisor offers alternative guidance for correct LT insertion.
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Saylor DM, Kim CS, Patwardhan DV, Warren JA. Diffuse-interface theory for structure formation and release behavior in controlled drug release systems. Acta Biomater 2007; 3:851-64. [PMID: 17553761 DOI: 10.1016/j.actbio.2007.03.011] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2006] [Revised: 01/29/2007] [Accepted: 03/07/2007] [Indexed: 10/23/2022]
Abstract
A common method of controlling drug release has been to incorporate the drug into a polymer matrix, thereby creating a diffusion barrier that slows the rate of drug release. It has been demonstrated that the internal microstructure of these drug-polymer composites can significantly impact the drug release rate. However, the effect of processing conditions during manufacture on the composite structure and the subsequent effects on release behavior are not well understood. We have developed a diffuse-interface theory for microstructure evolution that is based on interactions between drug, polymer and solvent species, all of which may be present in either crystalline or amorphous states. Because the theory can be applied to almost any specific combination of material species and over a wide range of environmental conditions, it can be used to elucidate and quantify the relationships between processing, microstructure and release response in controlled drug release systems. Calculations based on the theory have now demonstrated that, for a characteristic delivery system, variations in microstructure arising due to changes in either drug loading or processing time, i.e. evaporation rate, could have a significant impact on both the bulk release kinetics and the uniformity of release across the system. In fact, we observed that changes in process time alone can induce differences in bulk release of almost a factor of two and typical non-uniformities of +/-30% during the initial periods of release. Because these substantial variations may have deleterious clinical ramifications, it is critical that both the system microstructure and the control of that microstructure are considered to ensure the device will be both safe and effective in clinical use.
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Shin BS, Kim GS, Ko JS, Gwak MS, Yang M, Kim CS, Hahm TS, Lee SK. Comparison of femoral arterial blood pressure with radial arterial blood pressure and noninvasive upper arm blood pressure in the reperfusion period during liver transplantation. Transplant Proc 2007; 39:1326-8. [PMID: 17580132 DOI: 10.1016/j.transproceed.2007.02.075] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2006] [Accepted: 02/05/2007] [Indexed: 11/21/2022]
Abstract
PURPOSE The reperfusion period during liver transplantation is hemodynamically unstable. Accurate blood pressure measurements are the mainstay for the efficient management of abrupt cardiovascular changes. We sought to compare femoral arterial blood pressure (FABP) with radial arterial blood pressure (RABP) and noninvasive upper arm blood pressure (NIBP) in the reperfusion period. METHODS Thirty-six adult living donor liver recipients were enrolled in this prospective study. Blood pressures in 3 locations were simultaneously recorded from 1 minute before reperfusion to 15 minutes after reperfusion. We evaluated agreements between FABP and RABP and between FABP and NIBP using intraclass correlation coefficients. Also, we investigated the rates of postreperfusion syndrome (PRS) based on the measurements from 3 locations. RESULTS After reperfusion, the mean and diastolic RABP agreed more with the corresponding FABP than NIBP. However, systolic NIBP showed high agreement with FABP from 3 to 10 minutes after reperfusion in contrast with the moderate agreement between systolic RABP with FABP, and systolic values of NIBP than RABP were closer to FABP. The rates of PRS based on FABP, RABP, and NIBP measurements were 50.0% (18/36), 80.6% (29/36), and 50.0% (18/36), respectively. CONCLUSIONS We believe that NIBP in addition to RABP may be considered to be a reliable alternative when FABP is not available to evaluate hemodynamic instability in the reperfusion period during liver transplantation.
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