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1.
Ultramicroscopy ; 210: 112927, 2020 Mar.
Article in English | MEDLINE | ID: mdl-31923781

ABSTRACT

High resolution electron backscatter diffraction (HREBSD), an SEM-based diffraction technique, may be used to measure the lattice distortion of a crystalline material and to infer the geometrically necessary dislocation content. Uncertainty in the image correlation process used to compare diffraction patterns leads to an uneven distribution of measurement noise in terms of the lattice distortion, which results in erroneous identification of dislocation type and density. This work presents a method of reducing noise in HREBSD dislocation measurements by removing the effect of the most problematic components of the measured distortion. The method is then validated by comparing with TEM analysis of dislocation pile-ups near a twin boundary in austenitic stainless steel and with ECCI analysis near a nano-indentation on a tantalum oligocrystal. The HREBSD dislocation microscopy technique is able to resolve individual dislocations visible in TEM and ECCI and correctly identify their Burgers vectors.

2.
Transplant Proc ; 50(4): 1183-1186, 2018 May.
Article in English | MEDLINE | ID: mdl-29731090

ABSTRACT

BACKGROUND: Administrative processing by the police may affect the process involved in organ donation in the event of an accidental brain injury. The purpose of this study was to evaluate the knowledge and attitude of police toward brain-dead donors and organ donation. METHODS: This was a descriptive research study using a 41-item questionnaire. As of July 19, 2017, 11 police stations in Seoul had collected questionnaires completed by 115 police officers. Data were analyzed using SAS (version 9.4) software. RESULTS: There were statistically significant differences in the scores on knowledge about brain death/donation according to religion (P = .022). Attitude was significantly positively correlated with the knowledge about brain-death organ donation (P = .029). CONCLUSION: It is necessary to understand and cooperate with the police when processing brain death organs from accidents. Education about organ donation can enhance the information and knowledge of the police and can also help to establish a positive attitude about organ donation.


Subject(s)
Brain Death , Health Knowledge, Attitudes, Practice , Police , Tissue and Organ Procurement , Adult , Comprehension , Female , Humans , Male , Religion , Republic of Korea , Surveys and Questionnaires , Tissue Donors
3.
Transplant Proc ; 49(5): 1138-1141, 2017 Jun.
Article in English | MEDLINE | ID: mdl-28583544

ABSTRACT

INTRODUCTION: Along with developments in surgical and immunosuppression techniques, the success rate of small bowel transplantation has increased. In Korea, the incidence of small bowel transplantations has increased, and the longest surviving living donor recipient has now survived for over 12 years postsurgery. The purpose of this study was to assess the experiences of living donors for small bowel transplantation before, during, and after the transplantation. METHODS: In one hospital, we conducted interviews, based on open-ended questions, with three small bowel donors. We asked them about experiences during small bowel donation. The living donor's statements were analyzed using interpretive phenomenological analysis. RESULTS: Donors decided to donate because they felt "sorry for the suffering of a family member" and they had "faith in the medical staff." In the early phase after donation, living donors experienced physical changes in their body, including pain, fatigue, altered bowel habits, and abdominal discomfort. Despite temporary limitations in daily and social activities, support from family members allowed the donors to fully recover and return to normal physical, social, and psychological status. The donors mentioned they experienced love and support from their family, as well as satisfaction and pride from donation, during the entire process. CONCLUSION: We hope that the physical, psychological, and social experience of living donors during small bowel transplantation deduced in this study will serve as a foundation for the establishment of an intervention method to provide education before donation and help recovery after donation.


Subject(s)
Intestine, Small/transplantation , Living Donors/psychology , Adult , Female , Humans , Male , Republic of Korea
4.
Bone Marrow Transplant ; 50(11): 1459-64, 2015 Nov.
Article in English | MEDLINE | ID: mdl-26301966

ABSTRACT

We analyzed the incidence and risk factors for ocular GVHD in patients undergoing allogeneic hematopoietic stem cell transplantation (allo-HSCT) in Korea. In this retrospective, noncomparative, observational study, 635 subjects were included who had at least 2 years of follow-up ophthalmological examinations after allo-HSCT from 2009 to 2012 at Seoul St Mary's Hospital, Seoul, Korea. The mean duration between allo-HSCT and onset of ocular GVHD was 225.5±194.3 days. The adjusted incidence for acute ocular GVHD was 1.33% and that for chronic GVHD was 33.33%. In the multivariate analysis, preexisting diabetes mellitus (odds ratio (OR): 4.22, 95% confidence interval (CI): 1.66-10.72), repeated allo-HSCT (OR: 29.10, 95% CI: 1.02-8.28) and the number of organs that chronically developed GVHD by stage I (OR: 14.63, 95% CI: 9.81-21.84) increased risk of ocular GVHD. Careful monitoring of ocular GVHD is needed in patients with chronic GVHD in multiple organs and preexisting diabetes.


Subject(s)
Graft vs Host Disease/epidemiology , Hematopoietic Stem Cell Transplantation/adverse effects , Keratoconjunctivitis Sicca/epidemiology , Adult , Allografts , Comorbidity , Diabetes Mellitus/epidemiology , Female , Follow-Up Studies , Graft vs Host Disease/drug therapy , Graft vs Host Disease/etiology , Hematologic Diseases/therapy , Humans , Immunosuppressive Agents/therapeutic use , Incidence , Keratoconjunctivitis Sicca/drug therapy , Keratoconjunctivitis Sicca/etiology , Male , Middle Aged , Multiple Myeloma/therapy , Organ Specificity , Republic of Korea/epidemiology , Retrospective Studies , Risk Factors , Severity of Illness Index
5.
Transplant Proc ; 46(10): 3253-6, 2014 Dec.
Article in English | MEDLINE | ID: mdl-25498033

ABSTRACT

PURPOSE: The purpose of this study was to investigate the satisfaction of the families of brain dead donors with regard to donation processes as well as their emotions after the donation. METHOD: A cross-sectional survey study was performed that included 45 families of brain-dead donors in 1 hospital-based organ procurement organization (HOPO) in Korea between February 2007 and April 2011. RESULTS: Donor willingness and desire in life was the most frequent reason organs were donated (34.5%), followed by the advice of family members or friends (31.0%). Satisfaction with the organ donation processes was 4.04 of 6 points. In each category, the satisfaction with the decision of donation was the highest (4.96 points) and the satisfaction with the procedure of donation was the lowest (3.07 points); of each question, the satisfaction of "information and help on funeral arrangements was enough" and "the process of preparing the relevant documents was cumbersome" was the lowest. "Missing" the dead person and "pride" were the most common emotions experienced after organ donation (69.0% and 62.1%, respectively), followed by "grief," "family coherence," and "guilt." Religious practices were observed to be most helpful for psychological stress relief after donation, followed by spending time with family and friends. Moreover, 24.1% responded that they had not yet overcome their suffering. CONCLUSION: Because donors' own willingness is the most common reason that families choose donation, it is necessary to remind the public of the importance of organ donation through education and public relations using mass communication approaches. Additionally, because the families felt grief and guilt as well as missing their loved ones and pride regarding their dead loved ones after organ donation, continuous and systematic supports are needed to promote their psychological stability.


Subject(s)
Emotions , Family/psychology , Personal Satisfaction , Tissue Donors/psychology , Tissue and Organ Procurement/ethics , Adolescent , Adult , Brain Death , Child , Cross-Sectional Studies , Female , Humans , Male , Middle Aged , Republic of Korea , Young Adult
6.
Syst Biol (Stevenage) ; 1(2): 213-21, 2004 Dec.
Article in English | MEDLINE | ID: mdl-17051693

ABSTRACT

The epidermal growth factor receptor (EGFR) signalling pathway is a complex signalling process with a wide network of interactions. The activation of the mitogen-activated protein kinases (MAPKs) cascade by this activated EGFR has been well studied. MAPKs form a highly integrated network, which is essential for certain specialised cell functions. This paper presents a kinetic model for the MAPK pathway downstream of the EGFR using a biochemical simulator. The model includes 30 signalling events and 29 signalling molecules. The time course data were examined for the activation of each signalling component. The simulation provides a large volume of data, by monitoring the kinetics of the signalling components, which were compared experimentally using the PC12 cell line. The kinetic model corresponded well with the experimental results observed in the EGFR induced activation of proteins. An examination of the kinetic analysis of the multiple signalling events provides a quantitative framework for representing the EGFR signalling network.


Subject(s)
Epidermal Growth Factor/metabolism , ErbB Receptors/metabolism , Mitogen-Activated Protein Kinases/metabolism , Models, Biological , Signal Transduction/physiology , Animals , Computer Simulation , PC12 Cells , Phosphorylation , Rats , Sensitivity and Specificity
7.
Electrophoresis ; 22(11): 2173-8, 2001 Jul.
Article in English | MEDLINE | ID: mdl-11504049

ABSTRACT

More efficient and faster separation conditions for qualitative as well as quantitative analysis of neuropeptides in human plasma using capillary zone electrophoresis (CZE) have been developed. The analysis method for neuropeptides has been improved specifically to study thyroid hormone related neuropetides for the regulation of thyroid disease. In this study, we investigated the pretreatment methods, composition of the running buffer and rinsing procedures between runs in order to obtain more sensitive and faster separation of trace neuropeptides in plasma by CZE. The tested neuropeptides were somatostatin (SOMA), vasopressin (VP), neurotensin (NT), and thyrotropin-releasing hormone (TRH). Plasma samples were pretreated by deproteinization and solid-phase extraction method. The fraction of neuropeptides was reconstituted in 40% acetonitrile followed by ultrafiltration, and then analyzed by CZE. Resolution and sensitivity was improved using the separation buffer composition with 100 mM Tris-phosphate buffer (pH 2.0) while the sensitivity was further improved via a stacking method using the sample buffer of 40% acetonitrile. These sample pretreatment methods and buffer condition permit quantitative analysis on tested neuropeptides at the 20 ng/mL level. The rinsing procedures between runs using 90% ethanol dramatically shortened the rinsing time to 30 min.


Subject(s)
Electrophoresis, Capillary/methods , Neuropeptides/blood , Buffers , Electrophoresis, Capillary/statistics & numerical data , Humans , Neuropeptides/isolation & purification , Neurotensin/blood , Reproducibility of Results , Sensitivity and Specificity , Somatostatin/blood , Thyrotropin-Releasing Hormone/blood , Vasopressins/blood
8.
Electrophoresis ; 22(11): 2217-21, 2001 Jul.
Article in English | MEDLINE | ID: mdl-11504055

ABSTRACT

Due to its high resolving power and diverse application range, capillary electrophoresis (CE) has been successfully applied to the analysis of carbohydrates. In this paper, a method for the determination of high-molecular chitosan (Mr 200,000) using CE is presented. We studied the optimal condition of buffer pH and type, and column type for determination of chitosan. Optimal CE performance was found when employing 100 mM triethylamine (TEA)-phosphate buffer, pH 2.0 and untreated fused-silica capillary (50 microm x 27 cm) for the chitosan analysis. Under optimum conditions, excellent linear responses were obtained in the concentration range of 1.25-20 microM, with a linear correlation coefficient of 0.9983. The standard deviations of the migration time and peak area were found to be 2.5 and 6.4%, respectively. This method could be readily applied to chitosan determination in real biological samples and commercial products.


Subject(s)
Chitin/isolation & purification , Electrophoresis, Capillary/methods , Animals , Biopolymers/chemistry , Biopolymers/isolation & purification , Buffers , Carbohydrate Sequence , Chitin/analogs & derivatives , Chitin/blood , Chitin/chemistry , Chitosan , Ethylamines , Food Analysis/methods , Hydrogen-Ion Concentration , Molecular Sequence Data , Molecular Structure , Molecular Weight , Rats
9.
J Chromatogr A ; 924(1-2): 337-44, 2001 Jul 27.
Article in English | MEDLINE | ID: mdl-11521883

ABSTRACT

A competitive immunoassay based on capillary electrophoresis (CE) with laser-induced fluorescence (LIF) has been developed for the determination of recombinant hirudin (r-hirudin) in biological mixtures. Hirudin, a thrombin inhibitor, is a polypeptide of 65 amino acids. To check purity levels and perform pharmacokinetic studies of (r-hirudin), specific and reproducible analysis methods are demanded. The work involved the development of separation conditions allowing for routine analysis of plasma samples. In this study, r-hirudin was labeled with fluorescein isothiocyanate (FITC), and FITC-labeled r-hirudin was purified using high-performance liquid chromatography. The purified product was then mixed with the sample followed with the addition of anti-hirudin antibody. Free, antibody-bound, and tagged r-hirudin could be separated within 5 min by CE analysis using uncoated fused-silica capillary with high reproducibility. The developed method can be used to determine r-hirudin with good precision and a detection limit lower than 20 nM. This result demonstrates the feasibility of the CE-LIF immunoassay method for the determination of r-hirudin in plasma samples.


Subject(s)
Electrophoresis, Capillary/methods , Hirudins/analysis , Immunoassay/methods , Spectrometry, Fluorescence/methods , Antibodies/immunology , Hirudins/immunology , Lasers , Recombinant Proteins/analysis , Recombinant Proteins/immunology , Sensitivity and Specificity
10.
J Chromatogr B Biomed Sci Appl ; 754(2): 495-501, 2001 Apr 25.
Article in English | MEDLINE | ID: mdl-11339293

ABSTRACT

An efficient method for the determination of testosterone and pregnenolone in human nails using gas chromatography-mass spectrometry (GC-MS) with d3-testosterone as an internal standard is described. The method involves alkaline digestion and liquid-liquid extraction, with subsequent conversion to mixed pentafluoropenyldimethylsilyl-trimethylsilyl (flophemesyl-TMS) derivatives for sensitive analysis in the selected-ion monitoring (SIM) mode. The limit of detection (LOD) and limit of quantification (LOQ) were lowered to 0.1 and 0.2 pg/g, respectively, when 100 mg of nail-clippings were used. The mean recoveries of testosterone and pregnenolone were 89.8 and 86.7%, respectively, while good overall precision (% C.V.; 4.5-9.5) and accuracy (% bias; 3.9-8.4) were demonstrated. Linearity as a correlation coefficient was 0.9913 (testosterone) and 0.9965 (pregnenolone). When applied to fingernail and toenail samples from seven healthy men and nine healthy women, testosterone and pregnenolone were positively detected in the concentration range of 0.24-5.80 ng/g. The levels of two steroids studied in the nails were found to be higher in the male subjects than in the female subjects, and except for the toenails of the females, the levels of testosterone were higher than those of pregnenolone.


Subject(s)
Gas Chromatography-Mass Spectrometry/methods , Nails/chemistry , Pregnenolone/analysis , Testosterone/analysis , Adult , Female , Hair/chemistry , Humans , Male , Reproducibility of Results
11.
J Invest Dermatol ; 116(1): 57-61, 2001 Jan.
Article in English | MEDLINE | ID: mdl-11168798

ABSTRACT

In establishing a theory to predict male-pattern baldness, we investigated the correlation of testosterone, epitestosterone, and dihydrotestosterone with 5alpha-reductase in hair using gas chromatography-mass spectrometry. One hundred milligram hair samples were obtained from a group of balding subjects and their sons, as well as from a corresponding aged-matched, nonbalding group. The ratio of testosterone to epitestosterone was significantly greater (mean 46.41, p < 0.001; mean 35.83, p < 0.001, respectively) in the hair of balding fathers (n = 19, age 28-50 y) and their sons (n = 16, age 8-16 y) than in the hair of the nonbalding control subjects (mean 9.17 and 10.47, respectively). These findings demonstrate that analysis of terminal hair may not only provide a basis for predicting baldness when the subject is still young, but also for preventing and treating male-pattern baldness by controlling the steroid hormone balance.


Subject(s)
5-alpha Reductase Inhibitors , Alopecia/diagnosis , Alopecia/enzymology , Epitestosterone/physiology , Testosterone/physiology , Adolescent , Adult , Child , Dihydrotestosterone/metabolism , Epitestosterone/metabolism , Hair Follicle/chemistry , Humans , Male , Middle Aged , Reproducibility of Results , Testosterone/metabolism
12.
Appl Opt ; 40(30): 5509-16, 2001 Oct 20.
Article in English | MEDLINE | ID: mdl-18364837

ABSTRACT

To evaluate the uncertainty of concentration measurement using cavity ringdown spectroscopy, we analytically derived expressions for uncertainty for parameters, such as temperature, laser frequency, and ringdown time deviation, from the model equation. The uncertainties that are due to systematic errors in a practical cavity ringdown system were assessed through an experimental study of the PQ(35) transition in an A band of molecular oxygen. We found that, except for the line strength that is regarded as a reference value independent of the measurement, the laser frequency jitter is the largest uncertainty source in the system. Some practical requirements for minimizing the uncertainty in concentration measurements are discussed. We also demonstrated determination of the line strength of the PQ(35) transition line of oxygen to be 8.63(3) x 10(-27) cm(-1) with a relative uncertainty of less than 0.4%.

13.
Korean J Radiol ; 2(4): 235-8, 2001.
Article in English | MEDLINE | ID: mdl-11754332

ABSTRACT

Phlegmonous enteritis is a rare infective inflammatory disease of the intestine, predominantly involving the submucosal layer. It is difficult to diagnose and often fatal. Its association with alcoholism and various liver diseases, although rarely reported, is well documented. We report a case of phlegmonous enteritis in a male patient with congestive heart failure and colon cancer, and describe the ultrasonographic and CT findings.


Subject(s)
Colonic Neoplasms/complications , Enteritis/diagnostic imaging , Heart Failure/complications , Aged , Enteritis/complications , Humans , Male , Tomography, X-Ray Computed , Ultrasonography
14.
J Comput Assist Tomogr ; 24(4): 652-4, 2000.
Article in English | MEDLINE | ID: mdl-10966204

ABSTRACT

Biliary cystadenoma is a rare cystic neoplasm and constitutes only 5% of all intrahepatic cysts of biliary origin. We report a case of a 44-year-old woman with huge biliary cystadenoma in the subhepatic space, mimicking a cholecystic lymphangioma. Findings of various imaging modalities including reconstructed CT image are presented and correlated with surgical and pathologic findings.


Subject(s)
Adenoma, Bile Duct/diagnosis , Bile Duct Neoplasms/diagnosis , Bile Ducts, Intrahepatic , Lymphangioma, Cystic/etiology , Adenoma, Bile Duct/diagnostic imaging , Adenoma, Bile Duct/physiopathology , Adult , Bile Duct Neoplasms/diagnostic imaging , Bile Duct Neoplasms/physiopathology , Female , Humans , Magnetic Resonance Imaging/methods , Tomography, X-Ray Computed/methods , Ultrasonography
15.
J Cell Biochem ; 76(3): 386-93, 2000 Jan.
Article in English | MEDLINE | ID: mdl-10649436

ABSTRACT

Lysophosphatidic acid (LPA) is a lipid metabolite that induces the activation of mitogen-activated protein kinase (MAPK) through binding to the G protein-coupled receptor in a number of cell lines and cultures. Recent studies have revealed that LPA is able to rapidly induce the phosphorylation of MAPK through an epidermal growth factor (EGF) receptor-dependent pathway. We investigated the role of the EGF receptor in the signaling pathway initiated by LPA stimulation in nerve growth factor (NGF)-responsive PC12 cells well known to transiently retract their own neurites upon LPA stimulation. LPA-stimulated MAPK signaling was suppressed by the selective EGF receptor inhibitor and in the dominant negative mutant EGF receptor cell line. As in the EGF signaling pathway, the complex of EGF receptor with adapter proteins Shc and Sos was formed in response to LPA stimulation, suggesting there is an intracellular mechanism for transactivation. A neurite retraction assay was also performed to examine the role of the EGF receptor in PC12 cell differentiation, which related to the involvement of LPA-induced neurite retraction. These results suggest that the receptor tyrosine kinase can be activated in a ligand-independent manner through intracellular crosstalk between the signaling pathways.


Subject(s)
ErbB Receptors/metabolism , Lysophospholipids/metabolism , Animals , Calcium Signaling , Enzyme Activation/drug effects , GTP-Binding Proteins/metabolism , Lysophospholipids/pharmacology , Mitogen-Activated Protein Kinases/metabolism , Neurites/drug effects , Neurites/ultrastructure , PC12 Cells , Protein Kinase C/metabolism , Rats , Receptors, Cell Surface/agonists , Receptors, Cell Surface/metabolism , Signal Transduction/drug effects
16.
J Biosci Bioeng ; 89(5): 489-91, 2000.
Article in English | MEDLINE | ID: mdl-16232783

ABSTRACT

A tetrachloroethylene (PCE)-degrading gram-positive, endospore forming, anaerobic bacterium, strain DPH-1, was isolated from a contaminated site. The organism was identified as Clostridium bifermentans by 16S rRNA gene sequence analysis and based on its physiological characteristics. Strain DPH-1 could dechlorinate high concentrations of PCE (0.9 mM), via trichloroethylene (TCE) to cis-1,2-dichloroethylene (cDCE) at a rate of 0.43 micromol/h.mg protein, as well as a number of other halogenated aliphatic compounds.

17.
Appl Opt ; 39(12): 1941-5, 2000 Apr 20.
Article in English | MEDLINE | ID: mdl-18345091

ABSTRACT

We demonstrate a novel technique for measuring ultralow linear birefringence of supermirrors (high-reflectivity dielectric mirror coatings). The polarimetric cavity ringdown technique is used in conjunction with the differential detection scheme with circular polarization to enhance the measurement sensitivity. The technique could, in principle, provide the convenience and reliability of linear detection signals and a reasonable tolerance to experimental imperfections. Phase retardation and orientation of each cavity mirror can be determined separately without the influence of the other mirror. The minimum detectable phase retardation achieved experimentally with this technique is ~6 x 10(-8) rad.

18.
Biochem Biophys Res Commun ; 265(3): 625-9, 1999 Nov 30.
Article in English | MEDLINE | ID: mdl-10600471

ABSTRACT

Peptides derived from gp41 effectively block the gp41-mediated cell fusion or HIV infection. A 36-mer (naDP178), 51-mer (C51) and 27-mer peptide (C27) from the membrane proximal region of gp41 have been examined their interaction modes with the coiled-coil motif of gp41 presented in thioredoxin (Trx-N) or the bacterially expressed ectodomain of gp41 (Ec-gp41ec). All of these peptides effectively inhibited the gp41-mediated membrane fusion, however, they showed distinct interaction modes with Ec-gp41ec or Trx-N. C51 peptide bound tightly to Trx-N, and it increased the solubility of Ec-gp41ec. naDP178 showed very weak binding affinity to Trx-N, however, it effectively solubilized Ec-gp41ec. In contrast, C27 peptide showed significant binding to Trx-N; however, it did not affect the solubility of Ec-gp41ec. These interaction modes of C-peptides were assumed to be related to their different inhibitory mechanism against gp41-mediated cell fusion.


Subject(s)
HIV Envelope Protein gp41/metabolism , HIV Infections/etiology , HIV-1/pathogenicity , Membrane Fusion/physiology , Amino Acid Motifs , Amino Acid Sequence , Binding Sites , Escherichia coli/genetics , HIV Envelope Protein gp41/chemistry , HIV Envelope Protein gp41/genetics , HIV Infections/metabolism , HIV Infections/virology , HIV-1/genetics , HIV-1/metabolism , Humans , Molecular Sequence Data , Peptide Fragments/chemistry , Peptide Fragments/genetics , Peptide Fragments/metabolism , Protein Binding , Protein Structure, Secondary , Recombinant Proteins/chemistry , Recombinant Proteins/genetics , Recombinant Proteins/metabolism , Solubility , Thioredoxins/metabolism
19.
J Chromatogr A ; 853(1-2): 285-93, 1999 Aug 20.
Article in English | MEDLINE | ID: mdl-10486736

ABSTRACT

A capillary electrophoretic (CE) system coupled with a diode array UV detector was used for the assay of secretory phospholipase A2 (sPLA2) activity. This method is based on monitoring both the breakdown of substrates and the formation of products simultaneously using micellar electrokinetic chromatographic techniques. Under our developed separation conditions, we analyzed the substrates and products quantitatively, and investigated enzyme activity as a function of reaction time and presence of enzyme activator or inhibitor. Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry was also utilized to confirm the phosphatidylcholine, a substrate of sPLA2. In order to test the feasibility of the developed method for measurement of enzymatic activity, we compared it to the conventional radioactive assay method for sPLA2. On the basis of our results, the conventional method can be complemented, or even replaced, by this new CE method which possesses the advantages of short analysis time, use of non-radiolabeled and inexpensive substrates, simple measurement of enzymatic activity, and exact quantitation of substrate and product.


Subject(s)
Electrophoresis, Capillary/methods , Phospholipases A/analysis , Arachidonic Acid/analysis , Borates/chemistry , Buffers , Deoxycholic Acid/analysis , Hydrogen-Ion Concentration , Phosphatidylcholines/analysis , Phospholipases A/metabolism , Phospholipases A2 , Radioactive Tracers
20.
J Chromatogr A ; 853(1-2): 439-47, 1999 Aug 20.
Article in English | MEDLINE | ID: mdl-10486751

ABSTRACT

Micellar electrokinetic chromatography (MEKC) was successfully and conveniently applied to the chiral separation with the addition of cyclodextrins (CDs) as chiral selector to the running buffer. Chiral separation depended on the type of CD; in particular, beta-CD was effective for the chiral separation of racemorphan. We investigated the optimal conditions of type and concentration of CD as chiral selector for the routine enantiomeric separation of racemorphan with good reproducibility. The effects of other parameters such as buffer pH and detection wavelength were also investigated to obtain the optimum conditions for the enantiomeric separation of racemorphan. Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry was used for confirmation of racemorphan. The optimal conditions for enantiomeric separation of the racemorphan were as follows: 50 mM borate buffer at pH 9.4 with 50 mM SDS, 10 mM beta-CD and 20% 1-propanol, 57 cm x 50 microns fused-silica capillary column, and UV detection at 192 nm. Based on the developed method, racemorphan in human urine was also separated and determined using solid-phase extraction and MEKC.


Subject(s)
Chromatography, Micellar Electrokinetic Capillary/methods , Levorphanol/urine , Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization/methods , Humans , Hydrogen-Ion Concentration , Levorphanol/chemistry , Stereoisomerism
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