• Journal of the Korean Association of Oral and Maxillofacial Surgeons
• /
• v.49 no.4
• /
• pp.198-207
• /
• 2023

Objectives: This study investigated causative strains and their antibiotic sensitivity in patients who were hospitalized for maxillofacial odontogenic infections at a tertiary center in South Korea over the past 10 years with the aim of providing guidelines for the selection of appropriate empirical antibiotics. Materials and Methods: Patients with head and neck fascial space abscesses due to odontogenic infections who underwent incision and drainage surgery with pus culture tests between 2013 and 2022 at the Department of Oral and Maxillofacial Surgery, Dankook University Hospital were included. The bacterial isolates and antibiotic sensitivity of each strain were analyzed for 2013-2022, 2013-2017, and 2018-2022. The affected fascial spaces were classified into primary, secondary, and deep neck spaces. Results: In the 192 patients included in this study, 302 strains were detected. Viridans streptococcus had the highest frequency (51.7%), followed by Prevotella spp. (16.9%), Staphylococcus spp. (5.6%), and Klebsiella pneumoniae (4.6%). The identification rate of viridans streptococcus significantly increased from 41.8% in 2013-2017 to 60.9% in 2018-2022. Viridans streptococcus showed an antibiotic sensitivity of 80.5% to ampicillin; the sensitivity to penicillin antibiotics decreased over the study period. Antibiotic susceptibility was approximately 94% for third-generation cephalosporins. K. pneumoniae, which was identified at a high percentage in patients with deep neck space infection, showed increasing antibiotic resistance to most antibiotics over the study period. Conclusion: Viridans streptococcus was identified in head and neck fascial space abscesses with the highest frequency. Empirical antibiotics should be effective against this strain; penicillin antibiotics are considered inappropriate. For effective treatment of deep neck space abscesses, bacterial culture and antibiotic sensitivity tests performed as soon as possible are essential.

• Korean Journal of Environmental Agriculture
• /
• v.40 no.2
• /
• pp.108-117
• /
• 2021

BACKGROUND: Dichlobentiazox is a newly registered pesticide in Korea as a triazole fungicide and requires establishment of an official analysis method for the safety management. Therefore, the aim of this study was to determine the residual analysis method of dichlobentiazox for the five representative agricultural products. METHODS AND RESULTS: Three QuEChERS methods were applied to establish the extraction method, and the EN method was finally selected through the recovery test. In addition, various adsorbent agents were applied to establish the clean-up method. As a result, it was found that the recovery of the tested pesticide was reduced when using the d-SPE method with PSA and GCB, but C₁₈ showed an excellent recovery. Therefore this method was established as the final analysis method. For the analysis, LC-MS/MS was used with consideration of the selectivity and sensitivity of the target pesticide and was operated in MRM mode. The results of the recovery test using the established analysis method and inter laboratory validation showed a valid range of 70-120%, with standard deviation and coefficient of variation of less than 3.0% and 11.6%, respectively. CONCLUSION: Dichlobentiazox could be analyzed with a modified QuEChERS method, and the method determined would be widely available to ensure the safety of residual pesticides in Korea.

• Mass Spectrometry Letters
• /
• v.6 no.2
• /
• pp.43-47
• /
• 2015

Detection of mefenamic acid (M, non-steroidal anti-inflammatory drug, NSAIDs) and its metallodrug was investigated using electrospray ionization mass spectrometry (ESI-MS) and fluorescence spectroscopy. ESI-MS data (500 µL, 1×10-3 M) revealed high detection sensitivity for the drug and metallodrug. ESI-MS spectra revealed peaks at 242, 580, and 777 Da corresponding to [M+H]+, [63Cu(M-H)2(H2O)2+H]+, and [56Fe(M-H)3+H]+, respectively. The metal:mefenamic ratios of ESIMS spectra are in complete agreement with the fluorescence spectroscopy results (1:2 for Cu(II) and 1:3 for Fe(III)). ESI is a soft ionization technique that can be used on labile metallo-mefenamic acids and is promising for the detection of these species in environmental samples and biological fluids.

• Environmental Analysis Health and Toxicology
• /
• v.9 no.1_2
• /
• pp.19-23
• /
• 1994

The tetrazolium dye, 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT), is reduced by live but not dead cell, and this reaction is used as the end point in a rapid drug screening assay. It can also be used for accurate determinations of drug sensitivity but only if a quantative relationship is established between cell number and MTT-formazan production. Several conditions were examined to devise an in vitro assay method in primary cultured hepatocytes, such as optimum wavelength, optimal MTT concentration, optimal incubation time, and cell density.

• Asian Pacific Journal of Cancer Prevention
• /
• v.15 no.6
• /
• pp.2395-2403
• /
• 2014

As the recurrence and mortality rates of bladder cancer are high, research is needed to find suitable biomarkers for early detection, evaluation of prognosis, and surveillance of drug responses. We performed a computerized search of the Medline/PubMed databases with the key words bladder cancer, biomarker, early detection, prognosis and drug response. Several markers were identified at DNA, RNA and protein levels with different sensitivities and specificities. Only a few of the potential bladder cancer biomarkers have been approved for clinical use. Efforts now should be concentrated on finding a panel of markers with acceptable sensitivity and specificity for early detection of bladder cancer.

• Journal of mucopolysaccharidosis and rare diseases
• /
• v.1 no.1
• /
• pp.28-30
• /
• 2015

Biologics present a challenge to both the manufacturer and end user. They must usually be formulated as parenterals. However, they are often unstable in liquid form, due to their complex structure and composition. In that case, they must be manufactured using highly specialized processes, such as lyophilization (freeze-drying). Lyophilization nearly eliminates stability issues. Reducing a compound's sensitivity to temperature prolongs its shelf life. However, reconstitution can be cumbersome, involving multiple steps that increase the potential for error. Dual-chamber technology provides an effective alternative, combining a lyophilized drug and diluent in a closed system and enabling reconstitution in a few simple steps.

• Journal of Pharmaceutical Investigation
• /
• v.40 no.4
• /
• pp.201-212
• /
• 2010

Self-organized nanogels from polysaccharide derivatives offer a promising approach in treatment of cancer due to their flexibility in chemistry and their ability to improve the therapeutic index of a drug by modifying biodistribution by their preferential localization at target sites and lower distribution in normal healthy tissues. These properties have promoted studies of active cancer targeting by self-organized nanogels for even better accumulation in solid tumors. However although many researchers have reported their potential by using cell culture systems and small animal tumor models in cancer therapy, these nanogels need more decoration such as conjugation with targeting moiety and endowment of stimuli-sensitivity for precise targeting of the cancer site. In this review, we summarize the recent efforts in developing novel targeting approaches via active endocytosis and stimuli-sensitive systems responding to hyperthermic or acidic tumor pH conditions.

• Genomics & Informatics
• /
• v.9 no.4
• /
• pp.173-180
• /
• 2011

Recent trends in generating multiple, large-scale datasets provide new challenges to manipulating the relationship of different types of components, such as gene expression and drug response data. Integrative analysis of compound response and gene expression datasets generates an opportunity to capture the possible mechanism of compounds by using signature genes on diverse types of cancer cell lines. Here, we integrated datasets of compound response and gene expression profiles on NCI60 cell lines and constructed a network, revealing the relationship for 801 compounds and 341 gene probes. As examples, obtusol, which shows an exclusive sensitivity on a small number of colon cell lines, is related to a set of gene probes that have unique overexpression in colon cell lines. We also found that the SLC7A11 gene, a direct target of miR-26b, might be a key element in understanding the action of many diverse classes of anticancer compounds. We demonstrated that this network might be useful for studying the mechanisms of varied compound response on diverse cancer cell lines.

• Archives of Pharmacal Research
• /
• v.25 no.5
• /
• pp.704-708
• /
• 2002

A fast and sensitive protein staining method in sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) using both an acidic dye, Coomassie Brilliant Blue R-250 (CBBR) and a basic dye, Neutral Red (NR) is described. It is based on a counter ion-dye staining technique that employs oppositely charged two dyes to form an ion-pair complex. The selective binding of the free dye molecules to proteins in an acidic solution enhances the staining effect of CBBR on protein bands, and also reduces gel background. It is a rapid staining procedure, involving fixing and staining steps with short destaining that are completed in about 1 h. As the result, it showed two to fourfold increase in sensitivity comparing with CBBR staining. The stained protein bands can be visualized at the same time of staining.

• YAKHAK HOEJI
• /
• v.46 no.2
• /
• pp.108-112
• /
• 2002

Drug resistance is one of the most significant impediments to successful chemotherapy of cancer. Multidrug-resistance (MDR) is characterized by decreased cellular sensitivity to anticancer agents due to the overexpression of P-glycoprotein. By employing a resistant subline of HCT15 to adriamycin (CL02), we undertook the screening for agents which were effective to multidrug-resistant cancer cells. As a result, a myxobacterial strain JW150 was selected for study since an activity against CL02 cells was discovered in the strain. Cytotoxicity-guided fractionation of the culture broth led to the isolation of cystothiazole A and melithiazole F. The producing organism was identified as Myxococcus stipitatus by taxonomic comparison with type strains of Myxococcus sp. as well as its morphological and physiological characteristics. Cystothiazole A and melithiazole F demonstrated potent cytotoxicity against certain human cancer cells with $IC_{50}$ values ranging from 0.03~ $0.72{\mu}{\textrm{g}}$/ml. Both compounds were interestingly as active against drug-resistant sublines CL02 and CP70 as against the corresponding parental cells.