Biomedical subjects

Kyung-Eun Lee

Publications and source records attributed to Kyung-Eun Lee.

12 recordsLinked to original sources

PubMed2005

Bis(isothiocyanato)bis(phosphine) complexes of group 10 metals: reactivity toward organic isocyanides.

Treatment of Ni(NCS)2(PMe2Ph)2 with organic isocyanides CN-R gave five-coordinate isocyanide Ni(II) complexes, Ni(CN-R)(NCS)2(PMe2Ph)2 (R = C6H3-2,6-Me2 (1), t-Bu (2)). Interestingly, the corresponding reaction of Ni(NCS)2(P(n-Pr)3)2 with 2 equiv. of CN-t-Bu gave an unusual compound, which exists as an ion pair of the trigonal bipyramidal cation [Ni(P(n-Pr)3)2(CN-t-Bu)3]2+ (3) and the dinuclear NCS-bridged anion [Ni(1,3-micro-NCS)(NCS)3]2(2-) (4). In contrast, Pd(NCS)2(P(n-Pr)3)2 underwent substitution with 2 equiv. of CN-t-Bu to give the four-coordinate mono(isocyanide) Pd(II) complex Pd(NCS)(SCN)(CN-t-Bu)(P(n-Pr)3) (5) via phosphine dissociation. Reactions of M(NCS)2L2 (M = Pd, Pt; L = PMe3, PEt3, PMePh2, P(n-Pr)3) with two equiv. of CN-R (R = t-Bu, i-Pr, C6H3-2,6-Me2) gave the corresponding bis(isocyanide) complexes [M(CN-R)2(PR3)2](SCN)2 (7-13), except for Pd(NCS)2(PEt3)2 that reacted with CN-R' (R' = i-Pr, C6H3-2,6-Me2) and produced the mono(isocyanide) Pd(II) complexes [Pd(CN-R')(SCN)(PEt3)2](SCN) (14 and 15). Finally, treatment of M(NCS)2(PMe3)2 (M = Ni, Pd, Pt) with sterically bulky isocyanide CN-C6H3-2,6-i-Pr2 gave various products, (16-18) depending on the identity of the metal.

Journal Article↗

PubMed2005

The effect of cholesterol in the liposome bilayer on the stabilization of incorporated Retinol.

The effect of cholesterol in the liposome bilayer on the stability of incorporated retinol was studied. Retinol was incorporated into liposomes containing soybean phosphatidylcholine (PC) and cholesterol (CH) at various ratios, and the liposomes were prepared as multilamellar vesicles by the dehydration-rehydration method. Retinol readily incorporated into liposomes at a ratio of 0.01:1 (w/w) retinol:lipid, with over 94.52% being incorporated in all conditions studied. The incorporation efficiency of retinol increased slightly with increasing CH content in the liposome and with increasing pH of the hydration buffer. Average particle size increased as the CH content increased, and mean particle sizes at pH 5, 7, and 9 were 30.27, 89.53, and 41.42 microm, respectively. The time course of retinol degradation in aqueous solution in liposomes with various ratios of PC to CH was determined under a variety of pH conditions (pH 5, 7, and 9), and temperatures (4, 25, 37, and 50 degrees C). The stability of incorporated retinol was enhanced by increasing the CH content. At pH 7.0 and 4 degrees C, for example, 90.17% of the retinol in liposomes containing 50:50 (PC:CH) remained after 10 days of storage, whereas 51.46% remained at 100:0 (PC:CH). These results indicate that CH in liposomes greatly increases the incorporation efficiency of retinol and the stability of incorporated retinol.

Cholesterol↗

PubMed2004

Gefitinib (ZD1839) monotherapy as a salvage regimen for previously treated advanced non-small cell lung cancer.

PURPOSE: A worldwide compassionate-use program has enabled >42,000 patients with advanced non-small cell lung cancer (NSCLC) to receive gefitinib treatment. Here we report the outcome of gefitinib therapy in patients who enrolled in the "Iressa" Expanded Access Program at the Samsung Medical Center. EXPERIMENTAL DESIGN: Patients with advanced or metastatic NSCLC who had progressed after prior systemic chemotherapy and for whom no other treatment option was available were eligible to receive gefitinib treatment as part of the Expanded Access Program. A post hoc assessment of potential prognostic factors for response and survival was performed by multivariate analysis. RESULTS: All 111 evaluable patients had stage IV disease; most patients had a baseline performance status of 2 [n = 52 (47%)] or 3 [n = 18 (16%)] and had received >/=2 prior chemotherapy regimens (56%). The objective response rate was 26%, the disease control rate (measured over >/=8 weeks) was 40%, and the 1-year survival rate was 44%. Adenocarcinoma histology was associated with better response and disease control rates, and a performance status of 0-2 was also associated with a better disease control rate. Both of these factors, as well as female gender, were significantly associated with longer survival. Gefitinib was well tolerated; the most common adverse event was grade 1 skin rash. CONCLUSIONS: Gefitinib demonstrated significant antitumor activity and a favorable tolerability profile in this series of NSCLC patients with poor prognosis.

Adult↗

PubMed2004

Docetaxel plus cisplatin as second-line therapy in metastatic or recurrent advanced gastric cancer progressing on 5-fluorouracil-based regimen.

The purpose of this study was to determine the activity and safety of docetaxel plus cisplatin as second-line chemotherapy for advanced gastric cancer. This trial included patients who had failed first-line chemotherapy with a 5-fluorouracil regimen within 1 year before their enrollment. After registration, patients were treated with docetaxel intravenously at a dose of 60 mg/m2 given over 1 hour followed by cisplatin 60 mg/m2 given over 2 hours. The treatment was continued every 3 weeks until disease progression or unacceptable toxicity was detected. Forty-three patients were registered and 41 were assessable for response. Seven partial responses were observed (17.1% of the "evaluable" patients; 95% confidence interval [CI], 0-29) with a median response duration of 3.9 months. Stable disease was documented in 2 cases (4.9%). The median survival was 5.8 months (95% CI, 3.4-8.3), resulting in a 1-year survival rate of 23%. Tolerance was acceptable, with the main toxicity being neutropenia. The authors conclude that second-line chemotherapy with docetaxel plus cisplatin for advanced gastric cancer is feasible with an acceptable toxicity level.

Adenocarcinoma↗

PubMed2004

Tuberculosis in hematopoietic stem cell transplant recipients in Korea.

Hematopoietic stem cell transplantation (HSCT) results in impaired cell-mediated immunity, which subsequently increases the risk of infection from bacterial, fungal, and viral pathogens. Mycobacterial infections are commonly seen in immunodeficient patients, especially in endemic areas. Several series that have reviewed mycobacterial infections in HSCT patients reported incidences varying from less than 0.1% to 5.5%. From February 1996 to July 2003, we retrospectively reviewed records of 295 adult patients who underwent HSCT at Samsung Medical Center, Korea. Mycobacterial infections were diagnosed in 9 (3.1%) of the 295 transplant recipients. The time from HSCT to tuberculosis (TB) infection ranged from 45 days to 165 days posttransplantation. Analysis at the univariate level indicated that a conditioning regimen with total body irradiation (TBI), chronic graft-versus-host disease, and a previous history of TB infection were significant risk factors for the development of TB infection after HSCT. Multivariate analysis revealed that only a previous history of TB infection and TBI increased the risk of TB infection in HSCT patients (relative risk, 4.8 and 12.5, respectively). Isoniazid prophylaxis in HSCT recipients with only radiologic findings suggestive of past inactive TB infection did not significantly alter the incidence of TB infections (P = .236). In conclusion, a previous history of active TB infection and TBI were significant risk factors of TB infection following HSCT, and isoniazid prophylaxis may benefit HSCT recipients with a previous history of active TB infection.

Adult↗

PubMed2004

The outcomes of hypertransfusion in major ABO incompatible allogeneic stem sell transplantation.

Major ABO incompatibility may be potentially associated with immediate or delayed hemolysis and delayed onset of erythropoiesis in patients receiving allogeneic hematopoietic stem cell transplantation (HSCT). To determine if hemolysis can be prevented by the inhibition of graft erythropoiesis, we performed hypertransfusion and assessed red cell transfusion requirement and independence. Between October 1995 and December 2001, 28 consecutive patients receiving major ABO incompatible HSCT at Samsung Medical Center were hypertransfused to maintain their hemoglobin levels at 15 g/dL or more. We retrospectively compared the outcomes of these patients with those of 47 patients at Asan Medical Center whose target hemoglobin levels were 10 g/dL. Reticulocyte engraftment was significantly delayed in hypertransfused group (51 days vs. 23 days; p=.001). There was no significant difference in the total amount of red cells transfused within 90 days post-HSCT (25 units vs. 26 units; p=.631). No significant difference in the time to red cell transfusion independence was observed between the two groups (63 days vs. 56 days; p=.165). In conclusion, we failed to improve red cell transfusion requirement and independence in major ABO incompatible HSCT with hypertransfusion.

ABO Blood-Group System↗

PubMed2003

A phase II trial of concurrent chemoradiation therapy followed by consolidation chemotherapy with oral etoposide and cisplatin for locally advanced inoperable non-small cell lung cancers.

We report a phase II study to evaluate the survival rate, response rate and toxicity of concurrent chemoradiation therapy (CCRT) followed by consolidation chemotherapy (CT) with oral etoposide and cisplatin for patients with locally advanced inoperable non-small cell lung cancer (NSCLC). Fifty-four patients with locally advanced inoperable NSCLC who had received no prior therapy were enrolled into this trial between May 1995 and December 2000. Treatment consisted of two cycles of concurrent CT and four cycles of consolidation CT with oral etoposide (50 mg/m2) on days 1-14 during the CCRT courses and on days 1-21 during the consolidation CT courses, plus cisplatin (75 mg/m2 i.v.) on day 1 of a 28-day cycle. Conventional radiotherapy (1.8 Gy/fraction, 63 Gy over 7 weeks) was delivered from day 1 of the CT. Fifty-two patients were evaluable for response. Twelve patients (22%) achieved complete responses, and 32 patients (60%) achieved partial responses, for an overall response rate of 82% with a median duration of response of 9.1 months. Forty-three per cent developed grade 4 haematological toxicity, 11% grade 3 or 4 oesophagitis and 7% grade 3 or 4 lung toxicity. There were two treatment-related deaths, one from radiation pneumonitis and the other from sepsis. After a median follow-up duration of 50 months (range 20-85), the median overall survival time was 15.3 months (95% CI, 9.7-20.8), and the 1-, 2-, 3-, and 5 year overall survival rates were 62, 40, 30 and 16%, respectively. The duration of median progression-free survival was 12.3 months (95% CI, 7.4-17.3), and the 1-, 2-, 3-, and 5-year progression-free survival rates were 47, 40, 29 and 23%, respectively. Thus, concurrent conventional chest radiotherapy with oral etoposide plus cisplatin followed by consolidation CT led to an encouraging survival rate and prolongation of the time to progression, with moderate toxicity in patients with locally advanced inoperable NSCLC.

Administration, Oral↗

PubMed2003

A decision tree for selecting the most cost-effective waste disposal strategy in foodservice operations.

The purposes of this study were to determine costs of disposal strategies for wastes generated in foodservice operations and to develop a decision tree to determine the most cost-effective disposal strategy for foodservice operations. Four cases, including the central food processing center (CFPC) in a school district, a continuing-care retirement center (CCRC), a university dining center (UDC), and a commercial chain restaurant (CCR), were studied to determine the most cost-effective disposal strategy. Annual costs for the current and projected strategies were determined for each case. Results of waste characterization studies and stopwatch studies, interviews with foodservice directors, and water flow and electrical requirements from manufacturers' specifications were used to determine cost incurred. The annual percentage increases for labor, fees, and services were used to reflect an inflated economic condition for the ensuing 10 years of the study period. The Net Present Worth method was used to compare costs of strategies, and the multiparameter sensitivity analysis was conducted to examine the tolerance of the chosen strategy. The most cost-effective strategy differed among foodservice operations because of the composition of food and packaging wastes, the quantity of recyclable materials, the waste-hauling charges, labor costs, start-up costs, and inflation rate. For example, the use of a garbage disposal for food waste and landfills and recycling for packaging waste were the most cost-effective strategies for the CCRC. A decision tree was developed to illustrate the decision-making process that occurs when conducting cost analysis and subsequent decisions. Dietetics practitioners can use the decision tree when evaluating the results of the cost analysis.

Cost-Benefit Analysis↗

PubMed2003

Early concurrent chemoradiotherapy with prolonged oral etoposide and cisplatin for limited-stage small-cell lung cancer.

BACKGROUND: Combined chemoradiotherapy (CRT) is the standard treatment modality for limited-stage small-cell lung cancer (LSCLC), but the optimal timing of radiation is controversial. Prolonged oral etoposide has the advantage of prolonged exposure, which possibly leads to improved clinical outcome. We conducted a phase II trial of early concurrent CRT, starting from the very beginning of the first cycle of chemotherapy for previously untreated LSCLC. METHODS: Chemotherapy was given for six cycles, each consisting of oral etoposide (50 mg/m(2) daily from day 1 to 14) and intravenous cisplatin (75 mg/m(2) on day 1), every 3 weeks. Thoracic radiation therapy was given from day 1 of the first cycle of chemotherapy, administered at 2.0 Gy in 22 daily fractions to a total dose of 44 Gy. RESULTS: Forty-four patients were enrolled. The median age was 60 years (range, 42-77 years), including 15 patients (34%) over 65 years-of-age. We observed a complete response rate of 52% (95% CI, 37-67%), and an overall response rate of 88% in an intent-to-treat (ITT) analysis. Median overall survival was 14.9 months (95% CI, 11.4-18.3 months) and the median time to progression was 10.8 months (95% CI, 9.3-12.4 months) for the ITT population. In 220 cycles, grade 3-4 neutropenia was observed in 48% of cycles and grade 3-4 thrombocytopenia in 30% of cycles. Neutropenic fever was observed in 18 patients (41%). CONCLUSIONS: Early concurrent CRT, starting from the very beginning of the first cycle of chemotherapy with prolonged oral etoposide and cisplatin failed to show any improvement in survival compared with other CRT regimens.

Administration, Oral↗

PubMed2003

Adherent cells generated during long-term culture of human umbilical cord blood CD34+ cells have characteristics of endothelial cells and beneficial effect on cord blood ex vivo expansion.

Hematopoiesis depends on the association of hematopoietic stem cells with stromal cells that constitute the hematopoietic microenvironment. The in vitro development of the endothelial cell from umbilical cord blood (UCB) is not well established and has met very limited success. In this study, UCB CD34(+) cells were cultured for 5 weeks in a stroma-free liquid culture system using thrombopoietin, flt3 ligand, and granulocyte-colony stimulating factor. By week 4-5, we found that firmly adherent fibroblast-like cells were established. These cells showed characteristics of endothelial cells expressing von Willebrand factor, human vascular cell adhesion molecule-1, human intracellular adhesion molecule-1, human CD31, E-selectin, and human macrophage. Furthermore, when comparing an ex vivo system without an established endothelial monolayer to an ex vivo system with an established endothelial monolayer, better expansion of total nucleated cells, CD34(+) cells, and colony-forming units (CFUs)-granulocyte-macrophage and CFUs-granulocyte-erythroid-megakaryocyte-macrophage were found during culture. This phenomenon was in part due to the fact that a significant reduction of apoptotic fractions was found in the CD34(+) cells, which were cultured on the adherent monolayer for up to 5 weeks. To gather quantitative data on the number of endothelial cells derived from a given number of CD34 cells, we performed limiting dilution assay by using Poisson distribution: the number of tested cells (linear scale) producing a 37% negative culture (logarithmic scale) is the number of cells containing one endothelial cell. By this method, one endothelial cell may be found from 314 CD34(+) cells after 5 weeks of culture. These results suggest that the UCB CD34(+) cell fraction contains endothelial cell precursors, establishing the hematopoietic microenvironment and providing the beneficial effects through downregulating apoptosis on UCB expansion protocols. These observations may provide insight for future cellular therapy or graft engineering.

Antibodies↗

PubMed2002

Stabilization of retinol through incorporation into liposomes.

Chemical and photochemical processes during storage and preparation rapidly degrade retinol, the most active form of vitamin A. Therefore, the efficacy of incorporation into liposomes in order to modulate the kinetics of retinol degradation was investigated. Retinol was readily incorporated into multilamellar liposomes that were prepared from soybean phosphatidylcholine; the extent of the incorporation was 98.14 +/- 0.93% at pH 9.0 at a ratio of 0.01 : 1 (wt : wt) retinol : phospholipid. It was only marginally lower at higher retinol concentrations. The pH of the hydration buffer had a small effect. The incorporation efficiency ranged from 99.25 +/- 0.47% at pH 3 to 97.45 +/- 1.13% at pH 11. The time course of the retinol degradation in the aqueous solution in liposomes was compared to that of free retinol and free retinol with alpha-tocopherol under a variety of conditions of pH (3, 7, and 11), temperature (4, 25, 37, and 50 degrees ), and light exposure (dark, visible, and UV). The retinol that was incorporated into the liposomes degraded significantly slower than the free retinol or retinol with alpha-tocopherol at pH 7 and 11. At pH 3, where the free retinol degrades rapidly, the degradation kinetics were similar in liposomes and the presence of alpha-tocopherol. At pH 7.0 and 4 degrees in the light, for example, free aqueous retinol was completely degraded within 2 days, while only 20% of the retinol in the liposomes were degraded after 8 days. In general, the protective effect of the liposome incorporation was greater at low temperatures, at neutral and high pH, and in the dark. The results suggest that protection is greater in the solid, gel phase than in the fluid liquid crystalline phase lipids. These results indicate that the incorporation into liposomes can extend the shelf-life of retinol under a variety of conditions of temperature, pH, and ambient light conditions.

Drug Stability↗

PubMedDate not supplied

Genetically modified and wild soybeans: an immunologic comparison.

Most traits introduced into genetically engineered crops result from the expression of new proteins. As the first step toward assessing the allergenic potential of genetically modified organism (GMO) food, immunologic and physicochemical characterizations are needed. We prepared crude extract from GMO soybeans, wild soybeans, curd, and soy milk and then performed sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). After acidification with HCl, the samples were separated to globulin and whey. To evaluate changes in protein composition, either the samples were heated or pepsin was added. Polymerase chain reaction with primer encoding the 35S-promotor and the 3-enol-pyruvyl-shikimat-5-phosphat-synthase gene were performed, respectively, to detect the GMO component. SDS-PAGE results showed definite protein bands at 80 kDa in GMO soybean, 50 kDa in wild soybean, and a similar distribution of protein bands was noticed below 40 kDa. It was difficult to observe protein distribution because of modifications that occurred during processing in soybean-processed products. After heating, proteins of GMO and wild soybeans showed similar distributions and no distinct bands were detected at 50 and 80 kDa. Although SDS-PAGE analyses of raw GMO and wild soybeans differed, the same protein bands of 68, 37, and 20 kDa were observed in the globulin fraction after acidification. After adding pepsin, 20- and 68-kDa bands were found preserved in GMO and wild soybeans. The polymerase chain reaction procedures with primers specific to GMO soybeans showed that GMO soybeans and some curd samples included a GMO component. The skin test results of 49 patients showed 13 positive results to wild soybeans and 8 positive results to GMO soybeans. One patient had a positive skin test result to GMO soybeans only. Sera from nine patients with positive skin tests to the crude extract and a positive capsulated allergen product test to the soybean antigen were used for the immunoblotting of GMO and wild soybeans. GMO soybeans revealed a unique strong immunoglobulin E binding band at 25 kDa in some patients and wild soybeans showed a strong immunoglobulin E binding band at 30-36 kDa. To assess the allergenicity of GMO food, more research, including a selection of controlled sample materials and immunoassays of qualified sera, is needed.

Child↗