• Title/Summary/Keyword: false negative

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Ultrasonographic Features of Triple-Negative Breast Cancer: a Comparison with Other Breast Cancer Subtypes

  • Yang, Qi;Liu, Hong-Yan;Liu, Dan;Song, Yan-Qiu
    • Asian Pacific Journal of Cancer Prevention
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    • v.16 no.8
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    • pp.3229-3232
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    • 2015
  • Background: Triple-negative breast cancer (TNBC) is known to be associated with aggressive biologic features and a poor clinical outcome. Therefore, early detection of TNBC without missed diagnosis is a requirement to improve prognosis. Preoperative ultrasound features of TNBC may potentially assist in early diagnosis as characteristics of disease. Purpose: To retrospectively evaluate the sonographic features of TNBC compared to ER (+) cancers which include HER(-) and HER2 (+), and HER2 (+) cancers which are ER (-). Materials and Methods: From June 2012 through June 2014, sonographic features of 321 surgically confirmed ER (+) cancers (n=214), HER2 (+) cancers (n=66), and TNBC (n=41) were retrospectively reviewed by two ultrasound specialists in consensus. The preoperative ultrasound and clinicopathological features were compared between the three subtypes. In addition, all cases were analyzed using morphologic criteria of the ACR BI-RADS lexicon. Results: Ultrasonographically, TNBC presented as microlobulated nodules without microcalcification (p=0.034). A lower incidence of ductal carcinoma in situ (p<0.001), invasive tumor size that is>2 cm (p=0.011) and BI-RADS category 4 (p<0.001) were significantly associated with TNBC. With regard to morphologic features of 41 TNBC cases, ultrasonographically were most likely to be masses with irregular (70.7%) microlobulated shape (48.8%), be circumscribed (17.1%) or have indistinct margins (17.1%) and parallel orientation (68.9%). Especially TNBC microlobulated mass margins were more more frequent than with ER (+) (2.0%) and HER2 (+) (4.8%) cancers. Conclusions: TNBC have specific characteristic in sonograms. Ultrasonography may be useful to avoid missed diagnosis and false-negative cases of TNBC.

Internal Amplification Control for a Cryptosporidium Diagnostic PCR: Construction and Clinical Evaluation

  • Hawash, Yousry;Ghonaim, M.M.;Al-Hazmi, Ayman S.
    • Parasites, Hosts and Diseases
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    • v.53 no.2
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    • pp.147-154
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    • 2015
  • Various constituents in clinical specimens, particularly feces, can inhibit the PCR assay and lead to false-negative results. To ensure that negative results of a diagnostic PCR assay are true, it should be properly monitored by an inhibition control. In this study, a cloning vector harboring a modified target DNA sequence (${\approx}375bp$) was constructed to be used as a competitive internal amplification control (IAC) for a conventional PCR assay that detects ${\approx}550bp$ of the Cryptosporidium oocyst wall protein (COWP) gene sequence in human feces. Modification of the native PCR target was carried out using a new approach comprising inverse PCR and restriction digestion techniques. IAC was included in the assay, with the estimated optimum concentration of 1 fg per reaction, as duplex PCR. When applied on fecal samples spiked with variable oocysts counts, ${\approx}2$ oocysts were theoretically enough for detection. When applied on 25 Cryptosporidium-positive fecal samples of various infection intensities, both targets were clearly detected with minimal competition noticed in 2-3 samples. Importantly, both the analytical and the diagnostic sensitivities of the PCR assay were not altered with integration of IAC into the reactions. When tried on 180 randomly collected fecal samples, 159 were Cryptosporidium-negatives. Although the native target DNA was absent, the IAC amplicon was obviously detected on gel of all the Cryptosporidium-negative samples. These results imply that running of the diagnostic PCR, inspired with the previously developed DNA extraction protocol and the constructed IAC, represents a useful tool for Cryptosporidium detection in human feces.

Comparison of Culture, Conventional and Real-time PCR Methods for Listeria monocytogenes in Foods

  • Kim, Dong-Hyeon;Chon, Jung-Whan;Kim, Hyunsook;Kim, Hong-Seok;Choi, Dasom;Kim, Young-Ji;Yim, Jin-Hyeok;Moon, Jin-San;Seo, Kun-Ho
    • Food Science of Animal Resources
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    • v.34 no.5
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    • pp.665-673
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    • 2014
  • We compared standard culture methods as well as conventional PCR and real-time PCR for the detection of Listeria monocytogenes (L. monocytogenes) in milk, cheese, fresh-cut vegetables, and raw beef that have different levels of background microflora. No statistical differences were observed in sensitivity between the two selective media in all foods. In total, real-time PCR assay exhibited statistically excellent detection sensitivity (p<0.05) and was less time consuming and laborious as compared with standard culture methods. Conventional culture methods showed poor performance in detecting L. monocytogenes in food with high levels of background microflora, generating numerous false negative results. While the detection of L. monocytogenes in fresh cut vegetable by culture methods was hindered only by L. innocua, various background microflora, such as L. innocua, L. welshimeri, L. grayi, and Enterococcus faecalis appeared on the two selective media as presumptive positive colonies in raw beef indicating the necessity of improvement of current selective media. It appears that real-time PCR is an effective and sensitive presumptive screening tool for L. monocytogenes in various types of foods, especially foods samples with high levels of background microflora, thus complementing standard culture methodologies.

Frozen Section Biopsy to Evaluation of Obscure Lateral Resection Margins during Gastric Endoscopic Submucosal Dissection for Early Gastric Cancer

  • Kang, Eun-Jung;Cho, Joo-Young;Lee, Tae-Hee;Jin, So-Young;Cho, Won-Young;Bok, Jin-Hyun;Kim, Hyun-Gun;Kim, Jin-Oh;Lee, Joon-Seong;Lee, Il-Hyun
    • Journal of Gastric Cancer
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    • v.11 no.3
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    • pp.155-161
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    • 2011
  • Purpose: To determine the diagnostic utility of a frozen section biopsy in patients undergoing endoscopic submucosal dissection (ESD) for early gastric neoplasms with obscure margins even with chromoendoscopy using acetic acid and indigo carmine (AI chromoendoscopy). Materials and Methods: The lateral spread of early gastric neoplasms was unclear even following AI chromoendoscopy in 38 patients who underwent ESD between June 2007 and May 2011. Frozen section biopsies were obtained by agreement of the degree of lateral spread between two endoscopists. Thus, frozen section biopsies were obtained from 23 patients (FBx group) and not in the other 15 patients (AI group). Results: No significant differences were observed for size, histology, invasive depth, and location of lesions between the AI and FBx groups. No false positive or false negative results were observed in the frozen section diagnoses. Adenocarcinoma was revealed in three patients and tubular adenoma in one, thereby changing the delineation of lesion extent and achieving free lateral margins. The rates of free lateral resection margins and curative resection were significantly higher in the FBx group than those in the AI group. Conclusions: Frozen section biopsy can help endoscopists perform more safe and accurate ESD in patients with early gastric neoplasm.

Detecting Inner Attackers and Colluded nodes in Wireless Sensor Networks Using Hop-depth algorithm (Hop-depth 알고리즘을 이용한 무선 센서 네트워크상에서의 내부공격자 및 공모노드 검출)

  • Rhee, Kang-Hyeon
    • Journal of the Institute of Electronics Engineers of Korea CI
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    • v.44 no.1
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    • pp.113-121
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    • 2007
  • Commonly, in the Sensor Network that composed with multiple nodes uses Ad-hoc protocol to communicate each other. Each sensed data packets are collected by base node and processed by Host PC. But the Ad-hoc protocol is too vulnerable to Sinkhole attack, where the intruder attracts surrounding nodes with unfaithful routing information, and then performs selective forwarding or changes the data passing through it. The Sinkhole attack increases overhead over the network and boosts energy consumption speed to decrease network's life time. Since the other attacks can be easily adopted through sinkhole attack, the countermeasure must be considered carefully. In this paper, we proposed the Hop-depth algorithm that detects intruder in Sinkhole attack and colluded nodes. First, the proposed algorithm makes list of suspected nodes and identifies the real intruder in the suspected node list through the Hop-depth count value. And recalculates colluder's path information to find the real intruder. We evaluated the performance of the proposed algorithm using NS2. We compared and analyzed the success ratio of finding real intruder, false positive ratio, false negative ratio, and energy consumption.

Development of a Novel Immunochromatographic Assay for Rapid Detection of OXA-23 β-lactamase-producing Acinetobacter baumannii

  • Ji, Gil Young;Song, Hyung Geun;Jo, Mi Young;Hong, Seung Bok;Shin, Kyeong Seob
    • Biomedical Science Letters
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    • v.22 no.2
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    • pp.29-36
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    • 2016
  • Among the several agents causing carbapenem resistance of Acinetobacter baumannii, the most common cause is OXA-23 ${\beta}$-lactamase, which is known to hydrolyze carbapenem. To effectively control dissemination of carbapenem-resistant Acinetobacter baumannii (CRAB), development of both rapid and easy-to-use detection methods are required. The aim of this study is to develop a novel immunochromatographic assay (ICA) for rapid detection of OXA-23 ${\beta}$-lactamase. Of the seven monoclonal antibodies (mAbs) screened by ELISA, four mAbs (4G6, 4H6, 6G4, 9A4) exhibited high reactivity. Of these four specific antibodies, the combination of 6G4/4G6 showed the greatest reactivity and this combination of mAbs (6G4/4G6 mAbs) was used to develop the OXA-23 ${\beta}$-lactamase ICA. Of 102 A. baumannii isolates tested, the OXA-23 ${\beta}$-lactamase ICA results were consistent with PCR analysis except one false positive and one false negative isolate. The overall sensitivity and specificity were 98.36% and 97.56%, respectively. In conclusion, to the best of our knowledge, we have developed the first specific antibody set to detect OXA-23 ${\beta}$-lactamase using an ICA kit. This novel ICA can be used as a reliable and easy-to-use immunological assay for detection of OXA-23 ${\beta}$-lactamase producing CRAB in clinical laboratories.

Comparative Evaluation of Intron Prediction Methods and Detection of Plant Genome Annotation Using Intron Length Distributions

  • Yang, Long;Cho, Hwan-Gue
    • Genomics & Informatics
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    • v.10 no.1
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    • pp.58-64
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    • 2012
  • Intron prediction is an important problem of the constantly updated genome annotation. Using two model plant (rice and $Arabidopsis$) genomes, we compared two well-known intron prediction tools: the Blast-Like Alignment Tool (BLAT) and Sim4cc. The results showed that each of the tools had its own advantages and disadvantages. BLAT predicted more than 99% introns of whole genomic introns with a small number of false-positive introns. Sim4cc was successful at finding the correct introns with a false-negative rate of 1.02% to 4.85%, and it needed a longer run time than BLAT. Further, we evaluated the intron information of 10 complete plant genomes. As non-coding sequences, intron lengths are not limited by a triplet codon frame; so, intron lengths have three phases: a multiple of three bases (3n), a multiple of three bases plus one (3n + 1), and a multiple of three bases plus two (3n + 2). It was widely accepted that the percentages of the 3n, 3n + 1, and 3n + 2 introns were quite similar in genomes. Our studies showed that 80% (8/10) of species were similar in terms of the number of three phases. The percentages of 3n introns in $Ostreococcus$ $lucimarinus$ was excessive (47.7%), while in $Ostreococcus$ $tauri$, it was deficient (29.1%). This discrepancy could have been the result of errors in intron prediction. It is suggested that a three-phase evaluation is a fast and effective method of detecting intron annotation problems.

Fine Needle Aspiration Cytology of Intraoral Lesions (구강내 병변의 세침흡인 세포학적 소견)

  • Lee, Ho-Jung;Gong, Gyung-Yub;Chung, Dong-Hae;Huh, Joo-Ryung;Kim, On-Ja
    • The Korean Journal of Cytopathology
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    • v.9 no.2
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    • pp.155-159
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    • 1998
  • Fine needle aspiration cytology(FNAC) has become a popular method for the diagnosis of a wide variety of both superficial and deep-seated lesions. However, there are few reports about the potential of FNAC for the diagnosis of intraoral lesions. We experienced 44 FNACS from intraoral lesions at Asan Medical Center: 22 from the palate, 6 from the tongue, 5 from the parapharyngeal space, 5 from the lip, 2 from the floor of mouth, 1 from the buccal mucosa, and 3 from other intraoral sites. Histological confirmation was obtained in 32 cases and we analyzed 27 cases excluding 5 cases of inadequate aspirates. Diagnosis was specifically made in 19 of 27 cases(70%) including 1 mucoepidermoid carcinoma, 1 undifferentiated carcinoma, 1 chordoma, 9 pleomorphic adenomas, 1 neurofibroma, and 6 benign lesions. There were three false negative cases(sensitivity, 62.5%) and no false positive cases(specificity, 100%): Two cases diagnosed as "cystic lesion" were confirmed to be mucoepidermoid carcinomas and a case diagnosed as pleomorphic adenoma was proved to be adenoid cystic carcinoma. The results of our study suggest that FNAC is a useful technique in the diagnosis of intraoral lesion.

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Comparison of Histopathology, Serology and PCR for the Diagnosis of Malignant Catarrhal Fever (Malignant Catarrhal Fever의 병리조직학적 진단과 혈청학적 진단 및 PCR 진단법의 비교)

  • Kim, Ok-jin;Crawford, Timothy B.
    • Korean Journal of Veterinary Research
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    • v.43 no.3
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    • pp.471-476
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    • 2003
  • Malignant catarrhal fever (MCF) is a systemic disease of ruminants caused by ovine herpesvirus 2 (OvHV-2). OvHV-2 is a gamma herpesvirus, which induces frequent latent infection and often difficult to detect its antigens and even specific nucleic acids because of its low viral copies in the infected tissues. Histopathology, serology and polymerase chain reaction (PCR) were compared for the diagnosis of MCF using 10 bison infected with OvHV-2. Histopathological diagnosis was performed using the criteria which was based upon the pathognomic lesions. Serological diagnosis was conducted using its serum with competitive ELISA for the detection of antibodies of OvHV-2. Also, the nest PCR was performed with peripheral blood leukocytes for the detection of OvHV-2-specific DNAs. Primers 556 and 775 were used for the primary amplification, and primers 556 and 555 were used for the secondary amplification. As the results, positive cases were 6 by histopahology, 9 by serology and 10 by PCR. As comparing with other diagnostic methods, PCR was found to be more sensitive than histopathology and serology. The recent development of molecular diagnostic assays has provided powerful tools for investigating how viruses survive in nature. Development of PCR specific for viruses has dramatically improved the accuracy of diagnosis of viruses in clinically infected animals. Furthermore, amplification of viral genomic material by nest PCR represents the most sensitive method for the detection of viruses and might be detected successfully even though very low viral DNA copies. So, it could be used as the first choice for the detection of viral DNAs with low copies such as the status of latent infection. However, it has also some limitation of application like as false negative results by PCR inhibitors and false positive results by contamination. The results of this study suggest that the use of molecular biological methods like PCR may increase the accuracy for the diagnosis of infectious diseases. However, in diagnostic laboratory, it is recommended that PCR assay must be conducted with other diagnostic methods for more reliable diagnosis.

A Study on Detection Method of Multi-Homed Host and Implementation of Automatic Detection System for Multi-Homed Host (망혼용단말 탐지방법에 대한 연구 및 자동탐지시스템 구현)

  • Lee, Mi-hwa;Yoon, Ji-won
    • Journal of the Korea Institute of Information Security & Cryptology
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    • v.28 no.2
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    • pp.457-469
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    • 2018
  • This study aimed to investigate the fundamental reasons for the presence of multi-homed host and the risks associated with such risky system. Furthermore, multi-homed host detection methods that have been researched and developed so far were compared and analyzed to determine areas for improvement. Based on the results, we propose the model of an improved automatic detection system and we implemented it. The experimental environment was configured to simulate the actual network configuration and endpoints of an organization employing network segmentation. And the functionality and performance of the detection system were finally measured while generating multi-homed hosts by category, after the developed detection system had been installed in the experiment environment. We confirmed that the system work correctly without false-positive, false-negative in the scope of this study. To the best of our knowledge, the presented detection system is the first academic work targeting multi-homed host under agent-based.