• Research in Plant Disease
• /
• v.23 no.4
• /
• pp.306-313
• /
• 2017

Recently fire blight occurred in the Republic of Korea and eradication program for the disease has been executed since then. Specificity and detection sensitivity of the 2 antibody-based diagnostic strips to Korean isolates of Erwinia amylovora (Ea) and their application for on-site diagnosis were evaluated in this study. Ea AgriStrip, a commercial diagnostic kit, and EB strip, developed in this study, reacted positively to the all tested Korean Ea strains and also to most of Erwinia pyrifoliae (Ep) strains causing black shoot blight. They reacted negatively to all Pusedomonas syringae pv. syringae (Pss) strains that cause shoot blight on apple. Detection sensitivity was similar between the 2 strips. For on-site diagnosis, the two strips reacted positively only to the extractions of the fire-blighted samples on all fire blight occurred orchards except one orchard at which on-site diagnosis was carried out at winter time. In addition, they reacted positively to the black-shoot blighted extractions from the black shoot blight occurred apple orchard. These results suggest that both EB strip and Ea AgriStrip would be useful for on-site diagnosis of fire blight in Korea.

• Journal of Microbiology and Biotechnology
• /
• v.17 no.12
• /
• pp.1991-1995
• /
• 2007

O-Methylation is a common substitution reaction found in microbes as well as in mammalians. Some of the O-methyltransferases (OMTs) have broad substrate specificity and could be used to methylate various compounds. DnrK from Streptomyces peucetius encodes an anthracycline 4-O-methyltransferase, which uses carminomycin as a substrate, and its crystal structure has been determined. Molecular docking experiments with DnrK using various flavonoids were successfully conducted, and some of the flavonoids such as apigenin and genistein were predicted to serve as substrates. Based on these results, O-methylations of various flavonoids with the DnrK were successfully carried out. The methylation position was determined to be at the hydroxyl group of C7. Important amino acid residues for the enzymatic reaction of DnrK with apigenin could be identified using site-directed mutagenesis. Molecular docking could be useful to predict the substrate specificity ranges of other OMTs.

• Journal of Microbiology and Biotechnology
• /
• v.18 no.4
• /
• pp.663-669
• /
• 2008

The solvent-tolerant bacterium Enterobacter sp. VKGH12 is capable of utilizing n-butanol and contains an $NAD^+$-dependent n-butanol dehydrogenase (BDH). The BDH from n-butanol-grown Enterobacter sp. was purified from a cell-free extract (soluble fraction) to near homogeneity using a 3-step procedure. The BDH was purified 15.37-fold with a recovery of only 10.51, and the molecular mass estimated to be 38 kDa. The apparent Michaelis-Menten constant ($K_m$) for the BDH was found to be 4 mM with respect to n-butanol. The BDH also had a broad range of substrate specificity, including primary alcohols, secondary alcohols, and aromatic alcohols, and exhibited an optimal activity at pH 9.0 and $40^{\circ}C$. Among the metal ions studied, $Mg^{2+}$ and $Mn^{2+}$ had no effect, whereas $Cu^{2+},\;Zn^{2+}$, and $Fe^{2+}$ at 1 mM completely inhibited the BDH activity. The BDH activity was not inhibited by PMSF, suggesting that serine is not involved in the catalytic site. The known metal ion chelator EDTA had no effect on the BDH activity. Thus, in addition to its physiological significance, some features of the enzyme, such as its activity at an alkaline pH and broad range of substrate specificity, including primary and secondary alcohols, are attractive for application to the enzymatic conversion of alcohols.

• Asian Pacific Journal of Cancer Prevention
• /
• v.15 no.16
• /
• pp.6983-6987
• /
• 2014

Background: Modified toluidine blue staining (MTBs) is a simple, inexpensive and time saving method to detect H. pylori in gastric biopsy specimens. As a metachromatic stain, it simultaneously highlights intestinal metaplasia, a gastric cancer precancerous lesion. The aim of this study was to assess the reliability of MTBs compared with hematoxylin-eosin (H&E) for H. pylori detection using immunoperoxidase staining as the gold standard. This technique would be beneficial for a routine diagnosis and confirmation of H. pylori eradication in developing countries where endoscopic-based approaches are dominant. Materials and Methods: Esophagogastroduodenoscopy with triple site gastric biopsies was undertaken in 207 dyspeptic patients at Thammasat University Hospital, Thailand between 1997 and 1999. H&E, MTBs and immunoperoxidase staining were applied to each specimen. The presence or absence of H. pylori with each stain was interpreted separately and the sensitivity, specificity, positive and negative predictive values of H&E and MTBs were calculated. Results: A total of 282 specimens from 207 patients were evaluated. Using immunoperoxidase staining, organisms were positive in 117 specimens (41%). MTBs proved almost equally sensitive as immunoperoxidase (99%) and significantly more sensitive than H&E (85%). It has comparable specificity (96% vs 96%), PPV (95% vs 94%), and NPV (99% vs 90%) to H&E, using immunoperoxidase staining as gold standard. MTBs compared with immunoperoxidase staining, is cheaper (2 USD vs 12 USD) and faster (20 min vs 16 hrs) compared to immunoperoxidase staining. Conclusions: MTBs is effective, economical and easy to use in daily practice for the detection of H. pylori in gastric biopsy specimens. In addition to saving time in evaluating H. pylori associated gastritis, with a high sensitivity and ability to demonstrate intestinal metaplasia, the technique may have a role in confirmation of H. pylori eradication for gastric cancer prevention in a developing country setting.

• Journal of Chest Surgery
• /
• v.49 no.2
• /
• pp.99-106
• /
• 2016

Background: Barium swallow is performed following esophagectomy to evaluate the anastomosis for detection of leaks and to assess the emptying of the gastric conduit. The aim of this study was to evaluate the reliability of the barium swallow study in diagnosing anastomotic leaks following esophagectomy. Methods: Patients who underwent esophagectomy from January 2000 to December 2013 at our institution were investigated. Barium swallow was routinely done between days 5-7 to detect a leak. These results were compared to clinically determined leaks (defined by neck wound infection requiring jejunal feeds and or parenteral nutrition) during the postoperative period. The sensitivity and specificity of barium swallow in diagnosing clinically significant anastomotic leaks was determined. Results: A total of 395 esophagectomies were performed (mean age, 62.2 years). The indications for the esophagectomy were as follows: malignancy (n=320), high-grade dysplasia (n=14), perforation (n=27), benign stricture (n=7), achalasia (n=16), and other (n=11). A variety of techniques were used including transhiatal (n=351), McKeown (n=35), and Ivor Lewis (n=9) esophagectomies. Operative mortality was 2.8% (n=11). Three hundred and sixty-eight patients (93%) underwent barium swallow study after esophagectomy. Clinically significant anastomotic leak was identified in 36 patients (9.8%). Barium swallow was able to detect only 13/36 clinically significant leaks. The sensitivity of the swallow in diagnosing a leak was 36% and specificity was 97%. The positive and negative predictive values of barium swallow study in detecting leaks were 59% and 93%, respectively. Conclusion: Barium swallow is an insensitive but specific test for detecting leaks at the cervical anastomotic site after esophagectomy.

• Journal of Society of Preventive Korean Medicine
• /
• v.21 no.1
• /
• pp.41-48
• /
• 2017

Objectives : The aims of the current study were to assess the reliability and validity of the CoRe-Ditec-BS Questionnaire-II (BSQ-II; Blood stasis questionnaire-II) with 8 items including 5 items related women added to BSQ-I that was consisted of 36 items and developed in 2013. Methods : Between May 2014 and November 2014, 411 patients from 3 traditional Korean medical hospitals were asked to complete the BSQ-II. Each patient was independently diagnosed with BSS by two traditional Korean medical physicians from the same site. We estimated the internal consistency using Cronbach's ${\alpha}$ coefficient, the discriminant validity using the means score of BSS, and the predictive validity using logistic regression (sensitivity and specificity). Results : The BSQ-II had satisfactory internal consistency (Cronbach's ${\alpha}$ coefficient=0.765) and validity, with significant differences in the mean scores between the BSS($63.60{\pm}9.56$) and non-BSS groups($48.36{\pm}5.93$). The area under the receiver operating curve was about 98%, and the sensitivity and specificity were 91.4% and 94.9%, respectively. Conclusions : These results suggest that the CoRE-Ditec-BSQ-II is more reliable and valid instrument for estimating BSS than BSQ-I.

• Asian Pacific Journal of Cancer Prevention
• /
• v.17 no.9
• /
• pp.4487-4490
• /
• 2016

Background: Methylation at cg 16941656 of FRY is exclusively found in normal pancreatic tissue and has been proven to be specific for pancreatic-in-origin among several adenocarcinomas. Here, we investigated methylated DNA in the bile as a biomarker to differentiate the cause of obstruction between pancreatic cancer and benign causes. Materials and Methods: Bile samples of 45 patients with obstructive jaundice who underwent ERCP were collected and classified into pancreatic cancer (group 1) and benign causes (group 2) in 24 and 21 patients, respectively. DNA was extracted from bile and bisulfite modification was performed. After, methylation in cg 16941656 of FRY was identified by real-time PCR, with beta-actin used as a positive control. Results: Methylated DNA was identified in 10/24 (41.67%) and 1/21 (4.8%) of cases in groups 1 and 2, respectively (P= 0.012). The sensitivity, specificity, positive predictive value and negative predictive value to differentiate pancreatic cancer from benign causes were 42%, 95%, 91%, and 59%, respectively. Conclusions: Detecting a methylation at cg 16941656 of FRY in bile has high specificity, with an acceptable positive likelihood rate, and may therefore be helpful in distinguish pancreatic cancer from benign strictures.

• Journal of dental hygiene science
• /
• v.20 no.4
• /
• pp.206-212
• /
• 2020

Background: A Teachable Machine is a kind of machine learning web-based tool for general persons. In this paper, the feasibility of Google's Teachable Machine (ver. 2.0) was studied in the diagnosis of the tooth-marked tongue. Methods: For machine learning of tooth-marked tongue diagnosis, a total of 1,250 tongue images were used on Kaggle's web site. Ninety percent of the images were used for the training data set, and the remaining 10% were used for the test data set. Using Google's Teachable Machine (ver. 2.0), machine learning was performed using separated images. To optimize the machine learning parameters, I measured the diagnosis accuracies according to the value of epoch, batch size, and learning rate. After hyper-parameter tuning, the ROC (receiver operating characteristic) analysis method determined the sensitivity (true positive rate, TPR) and specificity (false positive rate, FPR) of the machine learning model to diagnose the tooth-marked tongue. Results: To evaluate the usefulness of the Teachable Machine in clinical application, I used 634 tooth-marked tongue images and 491 no-marked tongue images for machine learning. When the epoch, batch size, and learning rate as hyper-parameters were 75, 0.0001, and 128, respectively, the accuracy of the tooth-marked tongue's diagnosis was best. The accuracies for the tooth-marked tongue and the no-marked tongue were 92.1% and 72.6%, respectively. And, the sensitivity (TPR) and specificity (FPR) were 0.92 and 0.28, respectively. Conclusion: These results are more accurate than Li's experimental results calculated with convolution neural network. Google's Teachable Machines show good performance by hyper-parameters tuning in the diagnosis of the tooth-marked tongue. We confirmed that the tool is useful for several clinical applications.

• The Korean Journal of Pain
• /
• v.34 no.3
• /
• pp.339-345
• /
• 2021

Background: Ultrasound-guided caudal epidural injection (CEI) is limited in that it cannot confirm drug distribution at the target site without fluoroscopy. We hypothesized that visualization of solution flow through the inter-laminar space of the lumbosacral spine using color Doppler ultrasound alone would allow for confirmation of drug distribution. Therefore, we aimed to prospectively evaluate the usefulness of this method by comparing the color Doppler image in the paramedian sagittal oblique view of the lumbosacral spine (LS-PSOV) with the distribution of the contrast medium observed during fluoroscopy. Methods: Sixty-five patients received a 10-mL CEI of solution containing contrast medium under ultrasound guidance. During injection, flow was observed in the LSPSOV using color Doppler ultrasonography, following which it was confirmed using fluoroscopy. The presence of contrast image at L5-S1 on fluoroscopy was defined as "successful CEI." We then calculated prediction accuracy for successful CEI using color Doppler ultrasonography in the LS-PSOV. We also investigated the correlation between the distribution levels measured via color Doppler and fluoroscopy. Results: Prediction accuracy with color Doppler ultrasonography was 96.9%. The sensitivity, specificity, positive predictive value, and negative predictive value were 96.7%, 100%, 100%, and 60.0%, respectively. In 52 of 65 patients (80%), the highest level at which contrast image was observed was the same for both color Doppler ultrasonography and fluoroscopy. Conclusions: Our findings demonstrate that color Doppler ultrasonography in the LS-PSOV is a new method for determining whether a drug solution reaches the lumbosacral region (i.e., the main target level) without the need for fluoroscopy.

• Journal of Microbiology and Biotechnology
• /
• v.33 no.7
• /
• pp.964-972
• /
• 2023

Bacteriophage endolysins are peptidoglycan hydrolases composed of cell binding domain (CBD) and an enzymatically active domain. A phage endolysin CBD can be used for detecting bacteria owing to its high specificity and sensitivity toward the bacterial cell wall. We aimed to develop a method for detection of Enterococcus faecalis using an endolysin CBD. The gene encoding the CBD of ECP3 phage endolysin was cloned into the Escherichia coli expression vector pET21a. A recombinant protein with a C-terminal 6-His-tag (CBD) was expressed and purified using a His-trap column. CBD was adsorbed onto epoxy magnetic beads (eMBs). The bacterial species specificity and sensitivity of bacterial binding to CBD-eMB complexes were determined using the bacterial colony counting from the magnetic separations after the binding reaction between bacteria and CBD-eMB complexes. E. faecalis could bind to CBD-eMB complexes, but other bacteria (such as Enterococcus faecium, Staphylococcus aureus, Escherichia coli, Acinetobacter baumannii, Streptococcus mutans, and Porphyromonas gingivalis) could not. E. faecalis cells were fixed onto CBD-eMB complexes within 1 h, and >78% of viable E. faecalis cells were recovered. The E. faecalis recovery ratio was not affected by the other bacterial species. The detection limit of the CBD-eMB complex for E. faecalis was >17 CFU/ml. We developed a simple method for the specific detection of E. faecalis using bacteriophage endolysin CBD and MBs. This is the first study to determine that the C-terminal region of ECP3 phage endolysin is a highly specific binding site for E. faecalis among other bacterial species.