• Journal of Life Science
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• v.12 no.1
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• pp.49-54
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• 2002

Development of a rapid method possessing the requisite sensitivity and specificity for virus monitoring is necessary for protection of the shellfish-consuming public. Oysters tissue usually contains virus particles in relatively small concentrations along with various other substances that can interfere with detection steps. Therefore, the critical point concerning the detection of viruses in shellfish tissues resides in the processing of samples. The current study demonstrated the possibility of purifying small amounts of virus particles at the interface of a 10/50% sucrose gradient after a single round of sucrose gradient ultracentrifugation. We could detect HAV and poliovirus simultaneously from oyster tissues by using two different sets of primer. Furthermore, the method showed a high level of virus recovery rate (>95%) as determined by plaque assays of the final samples. Taken the advantages of the simple and sensitive methods, it was possible to detect 2 pfu of HAV in 5 g of oyster digestive tissues within 24h.

• Analytical Science and Technology
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• v.20 no.4
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• pp.347-354
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• 2007

A simple and rapid high-performance liquid chromatography assay for the determination of residual novobiocin levels in bovine, porcine, chicken, flatfish and japanese eel muscle has been developed and validated. The separation condition for HPLC/UV was optimized with phenyl hexyl ($4.6{\times}150mm$, $5{\mu}m$) column with 10 mM monobasic sodium phosphate buffer (pH 2.5)/acetonitrile (50/50, v/v) as the mobile phase at a flow rate of 1.0 mL/min and detection wavelength was set at 254 nm. Residues were extracted from tissue by blending with methanol and lipid materials were removed with n-hexane. Then, the methanol extract was evaporated to dryness under a nitrogen stream, reconstituted in the mobile phase. Aliquot of the organic extract was decanted and filtered through $0.45{\mu}m$ syringe filter. The $20{\mu}L$ of the resulting solution was injected into the HPLC system. The calibration ranges were $0.5{\sim}5{\mu}g/g$ and calibration curves were linear with coefficients of correlation better than 0.95. The limits of quantification were $0.5{\mu}g/g$ for all muscles. The recoveries of bovine, porcine, chicken, flatfish and japaneseel muscles were 99.8%, 102.4%, 91.0%, 104.0% and 93.0%, respectively. The procedures were validated according to the CODEX guideline, determining specificity, linearity, accuracy, precision, quantitation limit and recovery.

• Journal of the Korean Society of Radiology
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• v.17 no.6
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• pp.919-927
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• 2023

Elastography utilizes the fact that the tissue of a malignant tumor is harder than that of a benign tumor and increases the specificity of diagnosis according to the elastic modulus of the tumor, helping to reduce unnecessary biopsies. However, the reliability of elastography can be influenced by the equipment used and the examiner's skills. In this study, the researchers analyzed the reproducibility of elastography by evaluating phantom images when measuring the elasticity values repeatedly. Phantoms were created using silicone and gelatin with different levels of stiffness, and they were inserted at varying depths from the surface. The elasticity values were measured using shear wave elastography. The study aimed to determine whether the reproducibility of elasticity values remains consistent depending on the stiffness and depth of the lesions. The experimental results showed that there was no statistically significant correlation between the elasticity values obtained through shear wave elastography and the depth or stiffness of the lesions. However, in the lesions with the lowest stiffness, the elasticity values were statistically significant (p<0.001) and showed a high correlation with the depth of the lesions. Although there were variations in the measured elasticity values based on the differences in lesion stiffness and depth, these differences did not significantly impact the diagnosis. Therefore, shear wave elastography remains a reliable diagnostic method, and it is suggested that it can be helpful in the diagnosis of breast lesions.

• Korean Journal of Radiology
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• v.23 no.10
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• pp.1019-1027
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• 2022

Objective: Thyroidectomy bed lesions frequently show suspicious ultrasound (US) features after thyroid surgery. Fine-needle aspiration (FNA) may not provide definitive pathological information about the lesions. Although core-needle biopsy (CNB) has excellent diagnostic performance in characterizing suspicious thyroid nodules, no published studies have evaluated the performance of CNB specifically for thyroidectomy bed lesions. Therefore, we aimed to evaluate the diagnostic performance and safety of CNB for characterizing thyroidectomy bed lesions. Materials and Methods: A total of 124 thyroidectomy bed lesions in 113 patients (79 female and 34 male; age, 23-85 years) who underwent US-guided CNB between December 2008 and December 2020 were included. We reviewed the US imaging features of the target lesions and the histories of previous biopsies. The pathologic results, diagnostic performance for malignancy, and complications of CNB were analyzed. Results: All samples (100%) obtained by CNB were adequate for pathological analysis. Pathological analysis revealed inconclusive results in two lesions (1.6%). According to the reference standard, 50 lesions were ultimately malignant (40.3%), and 72 were benign (58.1%), excluding the two inconclusive lesions. The performance of CNB for diagnosing malignant thyroidectomy bed lesions in the 122 lesions had a sensitivity of 98.0% (49/50), a specificity of 100% (72/72), positive predictive value of 100% (49/49), and negative predictive value of 98.6% (72/73). Eleven lesions were referred for CNB after prior inconclusive FNA results in thyroidectomy bed lesions, for all of which CNB yielded correct conclusive pathologic diagnoses. According to the pathological analysis of CNB, there were various benign lesions (58.9%, 73/124) besides recurrence, including benign postoperative lesions other than suture granuloma (32.3%, 40/124), suture granuloma (15.3%, 19/124), remnant thyroid tissue (5.6%, 7/124), parathyroid lesions (4%, 5/124), and abscesses (1.6%, 2/124). No major or minor complications were associated with the CNB procedure. Conclusion: US-guided CNB is accurate and safe for characterizing thyroidectomy bed lesions.

• Korean Journal of Radiology
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• v.24 no.11
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• pp.1142-1150
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• 2023

Objective: To evaluate ^99mtechnetium-three polyethylene glycol spacers-arginine-glycine-aspartic acid (^99mTc-3PRGD₂) single-photon emission computed tomography (SPECT)/computed tomography (CT) imaging for diagnosing lymph node metastasis of primary malignant lung neoplasms. Materials and Methods: We prospectively enrolled 26 patients with primary malignant lung tumors who underwent ^99mTc-3PRGD₂ SPECT/CT and ¹⁸F-fluorodeoxyglucose (¹⁸F-FDG) positron emission tomography (PET)/CT imaging. Both imaging methods were analyzed in qualitative (visual dichotomous and 5-point grades for lymph nodes and lung tumors, respectively) and semiquantitative (maximum tissue-to-background radioactive count) manners for the lymph nodes and lung tumors. The performance of the differentiation of lymph nodes with and without metastasis was determined at the per-lymph node station and per-patient levels using histopathological results as the reference standard. Results: Total 42 stations had metastatic lymph nodes and 136 stations had benign lymph nodes. The differences between metastatic and benign lymph nodes in the visual qualitative and semiquantitative analyses of ^99mTc-3PRGD₂ SPECT/CT and ¹⁸F-FDG PET/CT were statistically significant (all P < 0.001). The area under the receiver operating characteristic curve (AUC) in the semi-quantitative analysis of ^99mTc-3PRGD₂ SPECT/CT was 0.908 (95% confidence interval [CI], 0.851-0.966), and the sensitivity, specificity, positive predictive value, and negative predictive value were 0.86 (36/42), 0.88 (120/136), 0.69 (36/52), and 0.95 (120/126), respectively. Among the 26 patients (including two patients each with two lung tumors), 15 had pathologically confirmed lymph node metastasis. The difference between primary lung lesions in patients with and without lymph node metastasis was statistically significant only in the semi-quantitative analysis of ^99mTc-3PRGD₂ SPECT/CT (P = 0.007), with an AUC of 0.807 (95% CI, 0.641-0.974). Conclusion: ^99mTc-3PRGD₂ SPECT/CT imaging may notably perform in the direct diagnosis of lymph node metastasis of primary malignant lung tumors and indirectly predict the presence of lymph node metastasis through uptake in the primary lesions.

• Korean Journal of Radiology
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• v.21 no.4
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• pp.431-441
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• 2020

Objective: To compare the diagnostic performance and interobserver variability of strain ratio obtained from one or two regions of interest (ROI) on breast elastography. Materials and Methods: From April to May 2016, 140 breast masses in 140 patients who underwent conventional ultrasonography (US) with strain elastography followed by US-guided biopsy were evaluated. Three experienced breast radiologists reviewed recorded US and elastography images, measured strain ratios, and categorized them according to the American College of Radiology breast imaging reporting and data system lexicon. Strain ratio was obtained using the 1-ROI method (one ROI drawn on the target mass), and the 2-ROI method (one ROI in the target mass and another in reference fat tissue). The diagnostic performance of the three radiologists among datasets and optimal cut-off values for strain ratios were evaluated. Interobserver variability of strain ratio for each ROI method was assessed using intraclass correlation coefficient values, Bland-Altman plots, and coefficients of variation. Results: Compared to US alone, US combined with the strain ratio measured using either ROI method significantly improved specificity, positive predictive value, accuracy, and area under the receiver operating characteristic curve (AUC) (all p values < 0.05). Strain ratio obtained using the 1-ROI method showed higher interobserver agreement between the three radiologists without a significant difference in AUC for differentiating breast cancer when the optimal strain ratio cut-off value was used, compared with the 2-ROI method (AUC: 0.788 vs. 0.783, 0.693 vs. 0.715, and 0.691 vs. 0.686, respectively, all p values > 0.05). Conclusion: Strain ratios obtained using the 1-ROI method showed higher interobserver agreement without a significant difference in AUC, compared to those obtained using the 2-ROI method. Considering that the 1-ROI method can reduce performers' efforts, it could have an important role in improving the diagnostic performance of breast US by enabling consistent management of breast lesions.

• Korean Journal of Radiology
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• v.20 no.4
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• pp.641-648
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• 2019

Objective: The purpose of this study was to investigate whether three-dimensional (3D) magnetic resonance imaging could improve diagnostic accuracy for suspected posterior ligamentous complex (PLC) disruption. Materials and Methods: We used 20 freshly harvested goat spine samples with 60 segments and intact surrounding soft tissue. The animals were aged 1-1.5 years and consisted of 8 males and 12 females, which were sexually mature but had not reached adult weights. We created a paraspinal contusion model by percutaneously injecting 10 mL saline into each side of the interspinous ligament (ISL). All segments underwent T2-weighted sagittal and coronal short inversion time inversion recovery (STIR) scans as well as coronal and sagittal 3D proton density-weighted spectrally selective inversion recovery (3D-PDW-SPIR) scans acquired at 1.5T. Following scanning, some ISLs were cut and then the segments were rescanned using the same magnetic resonance (MR) techniques. Two radiologists independently assessed the MR images, and the reliability of ISL tear interpretation was assessed using the kappa coefficient. The chi-square test was used to compare the diagnostic accuracy of images obtained using the different MR techniques. Results: The interobserver reliability for detecting ISL disruption was high for all imaging techniques (0.776-0.949). The sensitivity, specificity, and diagnostic accuracy of the coronal 3D-PDW-SPIR technique for detecting ISL tears were 100, 96.9, and 97.9%, respectively, which were significantly higher than those of the sagittal STIR (p = 0.000), coronal STIR (p = 0.000), and sagittal 3D-PDW-SPIR (p = 0.001) techniques. Conclusion: Compared to other MR methods, coronal 3D-PDW-SPIR provides a more accurate diagnosis of ISL disruption. Adding coronal 3D-PDW-SPIR to a routine MR protocol may help to identify PLC disruptions in cases with nearby contusion.

• KSBB Journal
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• v.23 no.4
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• pp.303-310
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• 2008

Bovine blood, cell, tissue, and organ are used as raw materials for manufacturing biologics such as biopharmaceuticals, tissue-engineered products, and cell therapy. Manufacturing processes for the biologics have the risk of viral contamination. Therefore viral validation is essential in ensuring the safety of the products. Bovine parainfluenza virus type 3 (BPIV3) is one of the common bovine pathogens and has widely been known as a contaminant of biologics. In order to establish the validation system for the BPIV3 safety of biologics, a real-time RT-PCR method was developed for quantitative detection of BPIV3 contamination in raw materials, manufacturing processes, and final products. Specific primers for amplification of BPIV3 RNA was selected, and BPIV3 RNA was quantified by use of SYBR Green I. The sensitivity of the assay was calculated to be 2.8 $TCID_{50}/mL$. The real-time RT-PCR method was validated to be reproducible and very specific to BPIV3. The established real-time RT-PCR assay was successfully applied to the validation of Chinese hamster ovary (CHO) cell artificially infected with BPIV3. BPIV3 RNA could be quantified in CHO cell as well as culture supernatant. Also the real-time RT-PCR assay could detect 7.8 $TCID_{50}/mL$ of BPIV3 artificially contaminated in bovine collagen. The overall results indicated that this rapid, specific, sensitive, and robust assay can be reliably used for quantitative detection of BPIV3 contamination during the manufacture of biologics.

• The Korean Journal of Nuclear Medicine
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• v.30 no.3
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• pp.299-314
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• 1996

The purpose of the present study was to validate the use of tissue radioactivity ratios instead of regional metabolic rates for the assessment of regional metabolic changes in Alzheimer's disease(AD) with [$^{18}F$]FDG PET and to examine the correlation of ratio indices with the severity of cognitive impairment in AD. Thirty-seven AD Patients(age $68{\pm}9 yrs$, $mean{\pm}s.d.$; 36 probable and 1 definite AD), 28 patients with dementia of non-Alzheimer type(age $66{\pm}7 yrs$), and 17 healthy controls(age $66{\pm}4 yrs$) underwent [$^{18}F$]FDG PET imaging. Two simplified radioactivity ratio indices were calculated from 37-66 min image: region-to-cerebellar radioactivity ratio(RCR) and a composite radioactivity ratio(a ratio of radioactivity in the most typically affected regions over the least typically affected regions: CRR). Local cerebral metabolic rate for glucose(LCMRglu) was also measured using a three-compartment, five-parameter tracer kinetic model. The ratio indices were significantly lower in AD patients than in controls(RCR in temporoparietal cortex, $0.949{\pm}0.136$ vs. $1.238{\pm}0.129$, p=0.0004; RCR in frontal cortex, $1.027{\pm}0.128$ vs. $1.361{\pm}0.151$, p<0.0001; CRR, $0.886{\pm}0.096$ vs. $1.032{\pm}0.042$. p=0.0024). On the RCR analysis, 86% of AD patients showed a pattern of bilateral temporoparietal hypometabolism with or without frontal involvement; hypometabolism was unilateral in 11% of the patients. When bilateral temporoparietal hypometabolism was considered to be suggestive of AD, the sensitivity and specificity of the RCR analysis for the differential diagnosis of AD were 86% and 73%, respectively. The RCR was correlated significantly with the macroparameter K [$K_1k_3/(k_2+k_3)$] (r=0.775, p<0.0001) and LCMRglu(r=0.633, p=0.0002) measured using the kinetic model. In patients with AD, both average RCR of cortical association areas and CRR were correlated with Mini-Mental Status Examination(r=0.565, p=0.0145; r=0.642, p=0.0031, respectively), Clinical Dementia Rating(r=-0.576, p=0.0124; r=-0.591, p=0.0077), and total score of Mattis Dementia Rating Scale (r=0.574, p=0.0648; r=0.737, p=0.0096). There were also significant correlations between memory and language impairments and corresponding regional RCRs. The results suggest that the [$^{18}F$]FDG PET ratio indices, RCR and CRR, reflect global and regional metabolic rates and correlate with the severity of cognitive impairment in AD. The simplified ratio analysis may be clinically useful for the differential diagnosis and serial monitoring of the disease.

• Korean Journal of Poultry Science
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• v.37 no.2
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• pp.167-172
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• 2010

An immunochromatograhy (IC) based infectious bursal disease virus (IBDV) detection kit, which employed two anti-IBDV VP2 monoclonal antibodies, was evaluated for rapid diagnosis of infectious bursal disease virus (IBD). The detection limit of the IC kit for IBDV was $10^{3.1}$ to $10^{3.9}$ $EID_{50}$/mL, indicating that the IC kit detected IBDV sensitively as same as double antigen capture ELISA but less than a RT-PCR assay. The IC kit did not detect other viral pathogens such as Newcastle disease virus, infectious bronchitis, avian influenza virus, and infectious larynotracheitis virus. When applied to tissue samples of experimental chickens died 3 or 4 days post infection after very virulent IBDV (strain Kr/D62) infection, the IC kit detected IBDV in all samples of the bursa of Fabricius, spleen, kidney, cecal tonsil and in 87.5%, 37.5% and 0% of liver, thymus and proventriculus samples. In particular, BF tissue samples showed stronger signal bands than other tissues. Positive signal was observed. All except for one thymus sample of samples having negative results by the IC kit showed the same result with DAS-ELISA but RT-PCR assay detected IBDV in some of IC kit negative samples of thymus and proventriculus. When swab samples from the bursa of Fabricius of dead chickens (n=231) on field farms were tested, the sensitivity and specificity of the IC assay relative to RT-PCR was 100% (109/109) and 97.5% (119/122), respectively and kappa value between both assay was 0.97. The kit can provide a useful aid for rapid detection of IBDV in chickens under field circumstances.