• Journal of Pharmaceutical Investigation
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• v.40 no.2
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• pp.101-107
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• 2010

A rapid and sensitive reversed-phase high performance liquid chromatography (HPLC) method was developed for the determination of N-(-4-Chlorophenyl)-6-hydroxy-7-methoxy-2-chromanecarboxamide (KAL-1120), a novel anti-inflammation agent, in the rat plasma. The method was applied to analyze the compound in the biological fluids such as bile, urine and tissue homogenates. After liquid-liquid extraction, the compound was analyzed on an HPLC system with ultraviolet detection at 275 nm. HPLC was carried out using reversed-phase isocratic elution with a $C_{18}$ column, a mobile phase of a mixture of acetonitril (40 v/v%) at a flow rate of 1.0 mL/min. The chromatograms showed good resolution and sensitivity and no interference of plasma. The calibration curve for the drug in plasma was linear over the concentration range of 0.05-50 ${\mu}g$/mL. The intra- and inter-day assay accuracies of this method ranged from 0.06% to 9.33% of normal values and the precision did not exceed 6.28% of relative standard deviation. The plasma concentration of KAL-1120 decreased to below the quantifiable limit at 1.5 hr after the i.v. bolus administration of 2-10 mg/kg to rats ($t_{1/2,({\alpha})}$ and $t_{1/2,({\beta})$ of 2.15 and 26.7 min at a dose of 2 mg/kg, 3.91 and 33.0 min at a dose of 10 mg/kg, respectively). The steady-state volume of distribution ($V_{dss}$) and the total body clearance ($CL_t$) were not significantly altered in rats given doses from 2 to 10 mg/kg. Of the various tissues tested, KAL-1120 was mainly distributed in the lung and heart after i.v. bolus administration. KAL-1120 was detected in the bile by 30 min after its i.v. bolus administration. However, the concentration in the urine after i.v. bolus administration became too low to measure, suggesting that KAL-1120 is mostly excreted in the bile. In conclusion, this analytical method was suitable for the preclinical pharmacokinetic studies of KAL-1120 in rats.

• Journal of Sensor Science and Technology
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• v.5 no.1
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• pp.30-36
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• 1996

ZnO thin-film sensors were fabricated by RF magnetron sputtering method. The composition of the device material was 4 wt. % $Al_{2}O_{3}$, 1 wt. % $TiO_{2}$ and 0.2 wt. % $V_{2}O_{5}$ on the basis of ZnO material for developing the high sensitive TMA gas sensor which have an appropriate resistivity and the stability for practical use. They were also grown on the $SiO_{2}/Si$ substrates heated at $250^{\circ}C$ under a pure oxygen pressure of about 10 mTorr with a power of about 80 watts for 10 minutes. So as to enhance the stability of the resistivity, the thin films were annealed from $400^{\circ}C$ to $800^{\circ}C$. The sensors made with the thin film which were annealed at $700^{\circ}C$ for 60 minutes in pure oxygen gas exhibited a good sensing properties for TMA gas. The thin film grown at this condition showed the maximum sensitivity of 550 in TMA gas concentration of 160 ppm, and exhibited a good stability and excellent linearity.

• Korean Journal of Clinical Laboratory Science
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• v.47 no.3
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• pp.125-131
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• 2015

The discovery of activating mutations in EGFR in a subset of lung adenocarcinomas was a major advance in our understanding of lung adenocarcinoma biology, and has led to groundbreaking studies that have demonstrated the efficacy of tyrosine kinase inhibitor therapy. Cytologic specimen procedures have become increasingly popular for obtaining diagnostic material in lung carcinomas. However, frequently the small amount of material or sparseness of tumor cells obtained from cytologic preparations limit the number of specialized studies, such as mutation analysis, that can be performed. In this study we used microdissection to isolate small numbers of tumor cells to assess for EGFR mutations from 76 cytological smear slides of patients with lung adenocarcinomas. We compared our results with previous molecular assays that had been performed on either surgical or cytology specimens as part of the patient's initial clinical work-up. Not only were we able to detect the identical EGFR mutation through the pyrosequencing, but we were also able to consistently detect the mutation from as few as 25 microdissected tumor cells. Furthermore, isolating a purer population of tumor cells resulted in increased sensitivity of mutation detection as we were able to detect mutations from microdissection-enriched cases. Therefore, microdissection can not only significantly increase the number of lung adenocarcinoma patients that can be screened for EGFR mutations, but can also facilitate the use of cytologic samples in the newly emerging field of molecular-based personalized therapies.

• Journal of Food Hygiene and Safety
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• v.27 no.1
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• pp.37-41
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• 2012

The current standard for testing tetrodotoxin (TTX) in foodstuffs is the mouse bioassay (MBA) in Korea as in many other countries. However, this test suffers from potential ethical concerns over the use of live animals. In addition, the mouse bioassay does not test for a specific toxin thus a sample resulting in mouse incapacitation would need further confirmatory testing to determine the exact source toxin (e.g., TTX, STX, brevotoxin, etc.). Furthermore, though the time of death is proportional to toxicity in this assay, the dynamic range for this proportional relationship is small thus many samples must be diluted and new mice be injected to yield a result that falls within the quantitative dynamic range. Therefore, in recent years, there have been many efforts in this field to develop alternative assays. High performance liquid chromatography (HPLC) coupled with mass spectrometry (MS) has been emerged as one of the most promising options. A LC-MS-MS method involves solid-phase extraction (SPE) and followed by analysis using an electrospray in the positive ionization mode and multiple reactions monitoring (MRM). To adopt LC-MS-MS method as alternative standard for testing TTX, we performed a validation study for the quantification of TTX in puffer fish. This LC-MS-MS method showed good sensitivity as limits of detection (LOD) of $0.03{\sim}0.08{\mu}g/g$ and limits of quantification (LOQ) of $0.10{\sim}0.25{\mu}g/g$. The linearity ($r^2$) of tetrodotoxin were 0.9986~0.9997, the recovery were 80.9~103.0% and the relative standard deviations (RSD) were 4.3~13.0%. The correlation coefficient between the mouse bioassay and LC/MS/MS method was higher than 0.95.

• Journal of Food Hygiene and Safety
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• v.25 no.2
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• pp.118-121
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• 2010

A HPLC-MS/MS method was developed for simultaneous determination of six sweeteners (acesulfame-K, cyclamate, saccharin, sucralose, stevioside, aspartame) in children's favorite foods. The procedure involves an extraction of the six sweeteners with 50% methanol solution, sample clean-up using the Carrez clearing reagent and filtering with cartridge filter. The HPLC separation was performed on a Hypersil Gold (150 mm ${\times}$ 2.1 mm 5 um) column using the water/acetonitrile mobile phase (95:5). Mass spectrometric analysis was carried out using the TSQ Quantum Ultra operated in negative and positive ESI/SRM. With this method, good linear relationship, sensitivity and reproducibility were obtained. The spike recoveries of six sweeteners for 2 kinds of foods spiked into 0.4 mg/ kg ranged from 87.4 to 114.7%. The detection limits were above 0.02 mg/kg. The method has been applied to determination of six sweeteners in children's favorite foods.

• Journal of Food Hygiene and Safety
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• v.28 no.4
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• pp.376-380
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• 2013

Determination of PFOS in instant food packing materials by LC-MS/MS was developed. The procedure involves an extraction of the Food Packing Materials with 100% methanol soxcelet extraction method. The LC separation was performed by Hypersil Gold ($150mm{\times}2.1mm$ 5 um) with mobile phases of 2 mM amoniumacetate solution and acetonitrile. The Mass spectral acquisition was done in negative ESI/SRM using the TSQ Quantum Ultra. With this method, good linear relationship, sensitivity and reproducibility were obtained. The rate of recoveries of PFOS from paper material spiked with 1.0 ug/L were 99.84%, respectively. The limit of quantitation and limit of detection were below 0.03 ug/L and 0.009 ug/L. The method had been applied to determination of PFOS in instant food packing materials.

• Journal of Biomedical Engineering Research
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• v.25 no.5
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• pp.329-334
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• 2004

The electronic nose (E-nose) recently finds its applications in medical diagnosis, specifically on detection of diabetes, pulmonary or gastrointestinal problem, or infections by examining odors in the breath or tissues with its odor characterizing ability. The odor recognition performance of E-nose can be improved by manipulating the sensor array responses of vapors in time-profile forms. The different chemical interactions between the sensor materials and the volatile organic compounds (VOC's) leave unique marks in the signal profiles giving more information than collection of the conventional piecemal features, i.e., maximum sensitivity, signal slopes, rising time. In this study, to use them in vapor recognition task conveniently, a novel time-profile method was proposed, which is adopted from digital image pattern matching. The degrees of matching between 8 different vapors were evaluated by using the proposed method. The test vapors are measured by the silicon-based gas sensor array with 16 CB-polymer composites installed in membrane structure. The results by the proposed method showed clear discrimination of vapor species than by the conventional method.

• Journal of Life Science
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• v.21 no.7
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• pp.947-952
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• 2011

A number of epidemiological studies have identified human papillomavirus (HPV) types 1, 2, 3, 4, 7, 10, 27, 57, and 65 in cutaneous common warts. However, identification of the HPV subtype by conventional polymerase chain reaction (PCR) is time consuming with its multi-step laboratory process. In this study, we aim to develop a specific one-step multiplex polymerase chain reaction method which capably identifies six different HPV genotypes related to common warts. By HPV DNA sequence analysis, 6 pairs of specific primers were designed from the intergenic regions of genes L1 to E6, and from genes E2 to L2. DNA sequence analysis with the L1 gene sequence of the sample was performed to measure the specificity of multiplex PCR. HPV-1, -2, -3, -4, -27, and -57 were identified without cross amplification in 109 out of 129 samples. The sensitivity and specificity of our set of primers in detecting HPV were 85% and 99.5%, respectively. For the 20 samples where HPV type was not identifiable by our batch of primer sets, multiplex PCR with an additional set of HPV primers was done, where 7 were found positive for HPV-7 or -65. Our results demonstrate that the newly designed multiplex PCR can rapidly detect the specific HPV subtype involved in common warts with high accuracy.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.32 no.2
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• pp.151-156
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• 2006

Purpose : The aim of this study was to determine the accuracy of clinical and radiologic assessments in detecting positive cervical lymph nodes in oral cancer. Materials and Methods : We had reviewed the preoperative clinical, radiologic and postoperative histopathologic reports of 46 patients who had been diagnosed as oral cancer and underwent surgical excision combined with neck dissection (52 sides of neck) in the Department of Oral and Maxillofacial Surgery, College of Dentistry, Yonsei University from the July 1, 1992 to the April 30, 1999. Results : The results were as follows 1. The male to female ratio was 4.38 : 1 and the mean age was 57. 2. Sensitivity values for the preoperative assessment of cervical lymph node metastasis in oral cancer were 62.5 % in clinical examination and 50.0 % in radiologic assessments. Specificity values were 77.8 % in clinical examination and 94.4 % in radiologic assessments. 3. False positive values were 44.4 % in clinical examination and 20.0 % in radiologic assessments. False negative values were 17.6 % in clinical and 19.0% in radiologic assessments. 4. Overall efficiency values were 73.1 % in clinical examination and 80.8 % in radiologic assessments. Summary : There were some limits on the accuracy of clinical and radiologic assessments in the preoperative detection of the cervical lymph nodes in oral cancer. To improve the accuracy, it is important to communicate between clinician and radiologist, and adjunctive diagnostic measures, ultrasound and fine needle aspiration cytology, were helpful increasing the overall efficiency. In the high risk sites (oral tongue and floor of the mouth) the false negative value is higher and the overall efficiency in radiologic evaluation is lower than those of the low risk sites (gingiva and alveolar ridge, retromolar trigone and buccal mucosa ). The elective neck dissection should be considered in the high risk sites.

• Tuberculosis and Respiratory Diseases
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• v.68 no.4
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• pp.205-211
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• 2010

Background: Procalcitonin is a well known marker in infection that plays a role in distinguishing between bacterial and viral infections in screening. The aim of the present study was to evaluate the role of procalcitonin in differentiating between 2009 H1N1 influenza pneumonia and community acquired pneumonia of bacterial origin, or mixed bacterial origin and 2009 H1N1 influenza infection. Methods: A retrospective observational study was performed over the 6-month winter period during the 2009 H1N1 influenza pandemic. Ninety-six patient-subjects were enrolled, all of whom had been diagnosed with community acquired pneumonia in emergency department during the study period. On admission, laboratory studies were performed, which included 2009 H1N1 influenza real-time polymerase chain reaction of nasal secretions and procalcitonin on serum; the laboratory values were compared between the study groups. Receiver operating characteristic curve analyses were performed on the resulting data. Results: Compared to those with bacterial or mixed infections (n=62) and bacterial pneumonia with confirmed organisms (n=30), patients with 2009 H1N1 pneumonia (n=34) were significantly more likely to have low procalcitonin levels (p=0.008, 0.001). Using cutoff of value >0.3 ng/mL, the sensitivity and specificity of procalcitonin for detection of patients with confirmed bacterial pneumonia were 76.2% and 60.6%, respectively. A significant difference in procalcitonin was found between 2009 H1N1 pneumonia and pneumonia caused by mixed influenza viral and bacterial infections (0.15 [0.05~0.84] vs. 10.3 [0.05~22.87] ng/mL, p=0.045). Conclusion: Serum procalcitonin measurement may assist in the discrimination between pneumonia of bacterial and of 2009 H1N1 influenza origin. High values of procalcitonin suggest that bacterial infection or mixed infection of bacteria and 2009 H1N1 influenza is more likely.