2.A clinical review of intussusception.
Pyeong Rang CHOO ; Sun Jin KIM ; Hyeon Suk KIM ; Ho Cheol SHIN ; Eun Sook PARK
Journal of the Korean Academy of Family Medicine 1991;12(6):10-20
No abstract available.
Intussusception*
3.Problems with interpretation of primary diagnostic tests for impotence.
Bong Cheol SEOK ; Hee Chang JUNG ; Hyeon Cheol SHIN ; Jun Kyu SUH ; Yeong Soo KIM ; Tong Choon PARK ; Hyeon Jin SHIN ; Jun Ha LEE
Korean Journal of Urology 1993;34(1):156-160
We analyzed the practical problems and factors which affect making the correct differential diagnosis in the interpretation or test results from the nocturnal penile tumescence (NPT) test and erotic stimulation test (EST). This was done to provide better information for higher diagnostic accuracy in the clinical application of these tests. The followings are the results of NPT tests and EST identifying the factors affecting correct differential diagnosis by comparison the other differential diagnostic methods. The overall sensitivity of NPT test (Number: 114 total patients) was 82%. 21 cases (18%) could not be diagnosed correctly due to traction of the sensor (12 cases, 10%) and sleep disturbance (9 cases, 8%). The overall sensitivity of EST (Number: 174 total patients) without considering the degree of patient`s sexual drive to erotic stimulation was 77%. 40 cases (23%) could not be diagnosed correctly due to tolerance to pornographic film (17 cases, 10 %), discomfort by the body attachments (14 cases, 8%) and traction of the sensor (9 cases, 5%). However, higher sensitivity (90%) and lower rate of incorrect diagnosis (10% ) were observed in 119 patients who showed Grade II or III (moderate to good) sexual drive to erotic stimulation. The results suggest that undesirable factors in the primary screening methods, traction of sensor, sleep disturbance in NPT test, and tolerance to pornographic film, discomfort by the body attachments, traction of sensor in EST must be taken into consideration when interpretation of test results is being performed.
Diagnosis
;
Diagnosis, Differential
;
Diagnostic Tests, Routine*
;
Erectile Dysfunction*
;
Humans
;
Male
;
Mass Screening
;
Penile Erection
;
Traction
4.Comparison of apical sealing ability of continuous wave of obturation technique using EndoTwinn and System B.
Hyun Ju SHIN ; Jeong Kil PARK ; Bock HUR ; Hyeon Cheol KIM
Journal of Korean Academy of Conservative Dentistry 2007;32(6):522-529
The purpose of this study was to compare the apical leakage of the root canal filled with the System B and the EndoTwinn (the combined application of heat and ultrasonic vibration). Sixty extracted premolars with straight root were cleaned and shaped to size 35. Group SB was obturated using System B and Group ET was filled with EndoTwinn. A size 35 of 0.06 tapered gutta- percha and Adseal were used and the plugger which could be introduced to 4 mm short of working length was selected in the obturation procedure. As the positive control, Group PC was not filled. In Group SB, ET and PC, all external surfaces of each tooth were coated with nail varnish leaving only 1 mm area around the apical foramen. In the negative control of Group NSB and Group NET, all of external tooth surface including apical foramen was coated with the nail varnish. The specimens were immersed in methylene blue dye solution for 2 days. Then the specimens were sectioned at each 1 mm from apex to 5 mm level. The final score of one specimen was given by summing up of the points at all levels. The dye leakage of Group ET was significantly less than that observed in Group SB (p < 0.05). And the frequency of gutta-percha pulling out from root canal when the plugger was removed was more often with the System B than with EndoTwinn but there was no significant difference.
Bicuspid
;
Dental Pulp Cavity
;
Gutta-Percha
;
Hot Temperature
;
Methylene Blue
;
Paint
;
Tooth
;
Tooth Apex
;
Ultrasonics
5.The Comparative Analysis of the Carotid Intima-Media Thickness and Homocysteine Level between Ischemic Stroke and Hypertensive Intracerebral Hemorrhage.
Dong Chul HAN ; Dong Jin SHIN ; Hyeon Mi PARK ; Cheol Wan PARK ; Yeong Bae LEE
Korean Journal of Cerebrovascular Surgery 2006;8(3):190-194
BACKGROUND: Carotid artery intima-media thickness (IMT) is an early structural marker of the atherosclerotic process and an elevated total homocysteine level is an early biochemical marker of atherosclerosis. But there are few reports about serum homocysteine level and carotid IMT between ischemic stroke, hypertensive intracerebral hemorrhage (HICH) and control group. METHOD: We studied about 173 patients with ischemic stroke, HICH and control group. Carotid IMT was defined as the mean of IMT measured by B-mode ultrasonography. Serum homocysteine level was measured by fluorescence polarization immunoassay method in fasting state. We compared serum homocysteine level and carotid IMT between ischemic stroke, HICH and control group. In statistics, One-Way ANOVA was used. RESULTS: A significant increase in carotid IMT was noted in ischemic stroke and HICH compared with that in the control group (p<0.05), whereas there was no significant differences in carotid IMT between ischemic stroke and HICH. The serum homocysteine level of ischemic stroke was significantly higher than that of control group (p<0.05). But there were no significant differences between HICH and control group, HICH and ischemic stroke. CONCLUSIONS: In our study, we thought a carotid IMT of ischemic stroke, HICH and serum homocysteine level in ischemic stroke can be used as early diagnostic marker. Therefore, our results address the need of further prospective clinical studies in patients with ischemic stroke and HICH in order to evaluate a possible diagnostic ability of carotid IMT and serum homocysteine level.
Atherosclerosis
;
Biomarkers
;
Carotid Arteries
;
Carotid Intima-Media Thickness*
;
Cerebral Hemorrhage
;
Fasting
;
Fluorescence Polarization Immunoassay
;
Homocysteine*
;
Humans
;
Intracranial Hemorrhage, Hypertensive*
;
Stroke*
;
Ultrasonography
6.Isolation and Identification of Aspergillus Section Fumigati Strains from Arable Soil in Korea.
Seung Beom HONG ; Dae Ho KIM ; In Cheol PARK ; Robert A SAMSON ; Hyeon Dong SHIN
Mycobiology 2010;38(1):1-6
63 strains of Aspergillus section Fumigati were isolated from 17 samples of arable soil in a central province of Korea. Based on the results of genotypic and phenotypic analyses, they were identified as Aspergillus fumigatus, A. lentulus, Neosartorya coreana, N. fennelliae, N. fischeri, N. glabra, N. hiratsukae, N. laciniosa, N. pseudofischeri, N. quadricincta, N. spinosa and N. udagawae. Among these, N. fennelliae, N. hiratsukae, N. quadricincta, and N. udagawae had not been previously recorded in Korea. The diversity of Aspergillus section Fumigati species from arable soil in Korea is also addressed.
Aspergillus
;
Aspergillus fumigatus
;
Korea
;
Neosartorya
;
Soil
7.Development of a UPLC-MS/MS method for the therapeutic monitoring of L-asparaginase
Hyeon Cheol JEONG ; Therasa KIM ; Deok Hwan YANG ; Kwang Hee SHIN
Translational and Clinical Pharmacology 2018;26(3):134-140
This study aimed to develop a UPLC-MS/MS method for determining plasma levels of L-aspartic acid and L-asparagine and the activity of L-asparaginase. L-aspartic acid, L-asparagine, and L-aspartic acid-2,3,3-d3 were extracted from human plasma by protein precipitation with sulfosalicylic acid (30%, v/v). The plasma samples were analyzed using an Imtakt Intrada amino acid analysis column with 25 mM ammonium formate and 0.5% formic acid in acetonitrile as the mobile phase with step gradient method at a flow rate of 0.5 mL/min. The injection volume was 5 µL, and the total run time was 15 min. Inter- and intra-batch accuracies (%) ranged from 96.62–106.0% for L-aspartic acid and 89.85–104.8%, for L-asparagine, and the coefficient of variation (CV%) did not exceed 7%. The validation results for L-aspartic acid and L-asparagine satisfied the specified criterion, however, the results for L-asparaginase activity assay showed a borderline validity. This study could be a foundation for further development of therapeutic drug monitoring systems using UPLC-MS/MS.
Ammonium Compounds
;
Asparagine
;
Aspartic Acid
;
Drug Monitoring
;
Humans
;
Methods
;
Plasma
8.Quantification of apixaban in human plasma using ultra performance liquid chromatography coupled with tandem mass spectrometry
Hyeon Cheol JEONG ; Tae Eun KIM ; Kwang Hee SHIN
Translational and Clinical Pharmacology 2019;27(1):33-41
Apixaban, an inhibitor of direct factor Xa, is used for the treatment of venous thromboembolic events or prevention of stroke. Unlike many other anticoagulant agents, it does not need periodic monitoring. However, monitoring is still required to determine the risk of bleeding due to overdose or surgery. Usually, apixaban concentrations are indirectly quantified using an anti-factor Xa assay. However, this method has a relatively narrow analytical concentration range, poor selectivity, and requires an external calibrator. Therefore, the goal of current study was to establish an analytical method for determining plasma levels of apixaban using ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). To this end, apixaban was separated using 2.5 mM ammonium formate (pH 3.0) (A) and 100% methanol containing 0.1% formic acid (B) using the gradient method with a Thermo hypersil GOLD column. The mass detector condition was optimized using the electrospray ionization (ESI) positive mode for apixaban quantification. The developed method showed sufficient linearity (coefficient of determination [r² ≥ 0.997]) at calibration curve ranges. The percentage (%) changes in accuracy, precision, and all stability tests were within 15% of the nominal concentration. Apixaban concentration in plasma from healthy volunteers was quantified using the developed method. The mean maximum plasma concentration (C(max)) was 371.57 ng/mL, and the median time to achieve the C(max) (T(max)) was 4 h after administration of 10 mg apixaban alone. Although the results showed low extraction efficiency (~16%), the reproducibility (% change was within 15% of nominal concentration) was reliable. Therefore, the developed method could be used for clinical pharmacokinetic studies.
Ammonium Compounds
;
Anticoagulants
;
Calibration
;
Chromatography, Liquid
;
Factor Xa
;
Healthy Volunteers
;
Hemorrhage
;
Humans
;
Mass Spectrometry
;
Methanol
;
Methods
;
Plasma
;
Stroke
;
Tandem Mass Spectrometry
9.Determination of candesartan or olmesartan in hypertensive patient plasma using UPLC-MS/MS
Hyeon-Cheol JEONG ; Yo-Han SEO ; Namyi GU ; Moo Yong RHEE ; Kwang-Hee SHIN
Translational and Clinical Pharmacology 2021;29(4):226-238
Candesartan and olmesartan are angiotensin II receptor blockers (ARBs) used for the treatment of hypertension and heart failure. Quantitation methods for candesartan and olmesartan were developed using ultra-high performance liquid chromatography-tandem mass spectrometry following protein precipitation. Candesartan was separated using 5 mM ammonium formate (A) and 100% acetonitrile (B) and olmesartan was separated using 2 mM ammonium formate with 0.1% formic acid (A) and 100% acetonitrile (B). Separation was performed using an isocratic method with a Thermo hypersil GOLD C18 column. Electrospray ionization was used for analyte ionization and detection of candesartan, olmesartan, and the internal standards by multiple reaction monitoring. Developed method showed excellent linearity (r > 0.99) in the concentration range of 2–500 ng/mL for candesartan and 5–2,500 ng/mL for olmesartan. were 86.70–108.8% for candesartan and 87.87–112.6% for olmesartan. These methods were able to successfully measure plasma candesartan or olmesartan concentrations in hypertensive patients. This study can be used for pharmacokinetic studies of candesartan or olmesartan in humans.
10.Physiologically-based pharmacokinetic model for clozapine in Korean patients with schizophrenia
Joomi LEE ; Min-Gul KIM ; Hyeon-Cheol JEONG ; Kwang-Hee SHIN
Translational and Clinical Pharmacology 2021;29(1):33-44
Clozapine has been used as a treatment of schizophrenia. Despite its large interindividual variability, few reports addressed the physiologically-based pharmacokinetic modeling and simulation (PBPK M&S) of clozapine in patients. This study aimed to develop a PBPK M&S of clozapine in Korean patients with schizophrenia. PBPK modeling for clozapine was constructed using a population-based PBPK platform, the SimCYP® Simulator (V19;Certara, Sheffield, UK). The PBPK model was developed by optimizing the physiological parameters of the built-in population and compound libraries in the SimCYP® Simulator. The model verification was performed with the predicted/observed ratio for pharmacokinetic parameters and visual predictive checks (VPCs) plot. Simulations were performed to predict toxicities according to dosing regimens. From published data, 230 virtual trials were simulated for each dosing regimen. The predicted/observed ratio for the area under the curve and peak plasma concentration was calculated to be from 0.78 to 1.34. The observation profiles were within the 5th and 95th percentile range with no serious model misspecification through the VPC plot. A significant impact on age and gender was found for clozapine clearance. The simulation results suggested that 150 mg twice a day and 150 mg three times a day of clozapine have toxicity concerns. In conclusion, a PBPK model was developed and reasonable parameters were made from the data of Korean patients with schizophrenia. The provided model might be used to predict the pharmacokinetics of clozapine and assist dose adjustment in clinical settings.