The product of triglycerides and glucose, a simple measure of insulin sensitivity. Comparison with the euglycemic-hyperinsulinemic clamp.

PubMed

Guerrero-Romero, Fernando; Simental-Mendía, Luis E; González-Ortiz, Manuel; Martínez-Abundis, Esperanza; Ramos-Zavala, María G; Hernández-González, Sandra O; Jacques-Camarena, Omar; Rodríguez-Morán, Martha

2010-07-01

To meet the worldwide challenge of emerging diabetes, accessible and inexpensive tests to identify insulin resistance are needed. To evaluate the sensitivity and specificity of the product of fasting, we compared the triglycerides and glucose (TyG) index, a simple measure of insulin resistance, with the euglycemic-hyperinsulinemic clamp test. We conducted a cross-sectional study of the general population and outpatients of the Internal Medicine Department at the Medical Unit of High Specialty of the Specialty Hospital at the West National Medical Center in Guadalajara, Mexico. Eleven nonobese healthy subjects, 34 obese normal glucose tolerance individuals, 22 subjects with prediabetes, and 32 diabetic patients participated in the study. We performed a euglycemic-hyperinsulinemic clamp test. Sensitivity and specificity of the TyG index [Ln(fasting triglycerides) (mg/dl) x fasting glucose (mg/dl)/2] were measured, as well as the area under the curve of the receiver operating characteristic scatter plot and the correlation between the TyG index and the total glucose metabolism (M) rates. Pearson's correlation coefficient between the TyG index and M rates was -0.681 (P < 0.005). Correlation between the TyG index and M rates was similar between men (-0.740) and women (-0.730), nonobese (-0.705) and obese (-0.710), and nondiabetic (-0.670) and diabetic (-0.690) individuals. The best value of the TyG index for diagnosis of insulin resistance was 4.68, which showed the highest sensitivity (96.5%) and specificity (85.0%; area under the curve + 0.858). The TyG index has high sensitivity and specificity, suggesting that it could be useful for identification of subjects with decreased insulin sensitivity.

Clock Drawing Test and the diagnosis of amnestic mild cognitive impairment: can more detailed scoring systems do the work?

PubMed

Rubínová, Eva; Nikolai, Tomáš; Marková, Hana; Siffelová, Kamila; Laczó, Jan; Hort, Jakub; Vyhnálek, Martin

2014-01-01

The Clock Drawing Test is a frequently used cognitive screening test with several scoring systems in elderly populations. We compare simple and complex scoring systems and evaluate the usefulness of the combination of the Clock Drawing Test with the Mini-Mental State Examination to detect patients with mild cognitive impairment. Patients with amnestic mild cognitive impairment (n = 48) and age- and education-matched controls (n = 48) underwent neuropsychological examinations, including the Clock Drawing Test and the Mini-Mental State Examination. Clock drawings were scored by three blinded raters using one simple (6-point scale) and two complex (17- and 18-point scales) systems. The sensitivity and specificity of these scoring systems used alone and in combination with the Mini-Mental State Examination were determined. Complex scoring systems, but not the simple scoring system, were significant predictors of the amnestic mild cognitive impairment diagnosis in logistic regression analysis. At equal levels of sensitivity (87.5%), the Mini-Mental State Examination showed higher specificity (31.3%, compared with 12.5% for the 17-point Clock Drawing Test scoring scale). The combination of Clock Drawing Test and Mini-Mental State Examination scores increased the area under the curve (0.72; p < .001) and increased specificity (43.8%), but did not increase sensitivity, which remained high (85.4%). A simple 6-point scoring system for the Clock Drawing Test did not differentiate between healthy elderly and patients with amnestic mild cognitive impairment in our sample. Complex scoring systems were slightly more efficient, yet still were characterized by high rates of false-positive results. We found psychometric improvement using combined scores from the Mini-Mental State Examination and the Clock Drawing Test when complex scoring systems were used. The results of this study support the benefit of using combined scores from simple methods.

Development and validation of a simple questionnaire for the identification of hereditary breast cancer in primary care

PubMed Central

2009-01-01

Background Breast cancer is a significant public health problem worldwide and the development of tools to identify individuals at-risk for hereditary breast cancer syndromes, where specific interventions can be proposed to reduce risk, has become increasingly relevant. A previous study in Southern Brazil has shown that a family history suggestive of these syndromes may be prevalent at the primary care level. Development of a simple and sensitive instrument, easily applicable in primary care units, would be particularly helpful in underserved communities in which identification and referral of high-risk individuals is difficult. Methods A simple 7-question instrument about family history of breast, ovarian and colorectal cancer, FHS-7, was developed to screen for individuals with an increased risk for hereditary breast cancer syndromes. FHS-7 was applied to 9218 women during routine visits to primary care units in Southern Brazil. Two consecutive samples of 885 women and 910 women who answered positively to at least one question and negatively to all questions were included, respectively. The sensitivity, specificity and positive and negative predictive values were determined. Results Of the 885 women reporting a positive family history, 211 (23.8%; CI95%: 21.5–26.2) had a pedigree suggestive of a hereditary breast and/or breast and colorectal cancer syndrome. Using as cut point one positive answer, the sensitivity and specificity of the instrument were 87.6% and 56.4%, respectively. Concordance between answers in two different applications was given by a intra-class correlation (ICC) of 0.84 for at least one positive answer. Temporal stability of the instrument was adequate (ICC = 0.65). Conclusion A simple instrument for the identification of the most common hereditary breast cancer syndrome phenotypes, showing good specificity and temporal stability was developed and could be used as a screening tool in primary care to refer at-risk individuals for genetic evaluations. PMID:19682358

Simple and rapid method for the detection of Filobasidiella neoformans in a probiotic dairy product by using loop-mediated isothermal amplification.

PubMed

Ishikawa, Hiroshi; Kasahara, Kohei; Sato, Sumie; Shimakawa, Yasuhisa; Watanabe, Koichi

2014-05-16

Yeast contamination is a serious problem in the food industry and a major cause of food spoilage. Several yeasts, such as Filobasidiella neoformans, which cause cryptococcosis in humans, are also opportunistic pathogens, so a simple and rapid method for monitoring yeast contamination in food is essential. Here, we developed a simple and rapid method that utilizes loop-mediated isothermal amplification (LAMP) for the detection of F. neoformans. A set of five specific LAMP primers was designed that targeted the 5.8S-26S rDNA internal transcribed spacer 2 region of F. neoformans, and the primer set's specificity was confirmed. In a pure culture of F. neoformans, the LAMP assay had a lower sensitivity threshold of 10(2)cells/mL at a runtime of 60min. In a probiotic dairy product artificially contaminated with F. neoformans, the LAMP assay also had a lower sensitivity threshold of 10(2)cells/mL, which was comparable to the sensitivity of a quantitative PCR (qPCR) assay. We also developed a simple two-step method for the extraction of DNA from a probiotic dairy product that can be performed within 15min. This method involves initial protease treatment of the test sample at 45°C for 3min followed by boiling at 100°C for 5min under alkaline conditions. In a probiotic dairy product artificially contaminated with F. neoformans, analysis by means of our novel DNA extraction method followed by LAMP with our specific primer set had a lower sensitivity threshold of 10(3)cells/mL at a runtime of 60min. In contrast, use of our novel method of DNA extraction followed by qPCR assay had a lower sensitivity threshold of only 10(5)cells/mL at a runtime of 3 to 4h. Therefore, unlike the PCR assay, our LAMP assay can be used to quickly evaluate yeast contamination and is sensitive even for crude samples containing bacteria or background impurities. Our study provides a powerful tool for the primary screening of large numbers of food samples for yeast contamination. Copyright © 2014 Elsevier B.V. All rights reserved.

Comparative study of dot enzyme immunoassay (Typhidot-M) and Widal test in the diagnosis of typhoid fever.

PubMed

Narayanappa, D; Sripathi, Rachana; Jagdishkumar, K; Rajani, H S

2010-04-01

We compared the sensitivity and specificity of Typhidot-M and Widal test with blood culture (gold standard) for diagnosing typhoid fever in 105 children aged 1-15 years admitted with clinical suspicion of typhoid fever. Of the 105 cases, blood culture was positive for S.typhi in 41 (39%) children, Widal test was positive in 48 (45.7%) and Typhidot-M was positive in 78 (74.3%) cases. Sensitivity and specificity of Typhidot-M was 92.6% and 37.5% while sensitivity and specificity of Widal test was 34.1% and 42.8%, respectively. In children with fever of less than 7 days duration, Typhidot-M was positive in 97%, compared to 24.2% by Widal test. Typhidot-M is a simple and sensitive test for early diagnosis of typhoid fever in children.

Record of hospitalizations for ambulatory care sensitive conditions: validation of the hospital information system.

PubMed

Rehem, Tania Cristina Morais Santa Barbara; de Oliveira, Maria Regina Fernandes; Ciosak, Suely Itsuko; Egry, Emiko Yoshikawa

2013-01-01

To estimate the sensitivity, specificity and positive and negative predictive values of the Unified Health System's Hospital Information System for the appropriate recording of hospitalizations for ambulatory care-sensitive conditions. The hospital information system records for conditions which are sensitive to ambulatory care, and for those which are not, were considered for analysis, taking the medical records as the gold standard. Through simple random sampling, a sample of 816 medical records was defined and selected by means of a list of random numbers using the Statistical Package for Social Sciences. The sensitivity was 81.89%, specificity was 95.19%, the positive predictive value was 77.61% and the negative predictive value was 96.27%. In the study setting, the Hospital Information System (SIH) was more specific than sensitive, with nearly 20% of care sensitive conditions not detected. There are no validation studies in Brazil of the Hospital Information System records for the hospitalizations which are sensitive to primary health care. These results are relevant when one considers that this system is one of the bases for assessment of the effectiveness of primary health care.

Simple detection of residual enrofloxacin in meat products using microparticles and biochips.

PubMed

Ha, Mi-Sun; Chung, Myung-Sub; Bae, Dong-Ho

2016-05-01

A simple and sensitive method for detecting enrofloxacin, a major veterinary fluoroquinolone, was developed. Monoclonal antibody specific for enrofloxacin was immobilised on a chip and fluorescent dye-labelled microparticles were covalently bound to the enrofloxacin molecules. Enrofloxacin in solution competes with the microparticle-immobilised enrofloxacin (enroMPs) to bind to the antibody on the chip. The presence of enrofloxacin was verified by detecting the fluorescence of enrofloxacin-bound microparticles. Under optimum conditions, a high dynamic range was achieved at enrofloxacin concentrations ranging from 1 to 1000 μg kg(-1). The limits of detection and quantification for standard solutions were 5 and 20 μg kg(-1) respectively, which are markedly lower than the maximum residue limit. Using simple extraction methods, recoveries from fortified beef, pork and chicken samples were 43.4-62.3%. This novel method also enabled approximate quantification of enrofloxacin concentration: the enroMP signal intensity decreased with increasing enrofloxacin concentration. Because of its sensitivity, specificity, simplicity and rapidity, the method described herein will facilitate the detection and approximate quantification of enrofloxacin residues in foods in a high-throughput manner.

Antibody conjugated glycine doped polyaniline nanofilms as efficient biosensor for atrazine

NASA Astrophysics Data System (ADS)

Bhardwaj, Sanjeev K.; Sharma, Amit L.; Kim, Ki-Hyun; Deep, Akash

2017-12-01

Atrazine is an important member of triazine family of pesticides. The development of its detection methods gained great attention due to the potential health risks associated with its contamination in various media including water, soil, and food. The contamination of atrazine in drinking water beyond the legal permissible limit of EPA (e.g. 3 ng ml-1) may cause various damages to living organisms (e.g. heart, urinary, and limb defects). In this research, we discuss the potential significance of a highly sensitive conductometric immunosensor for sensing the atrazine pesticide. To this end, electrochemical assembly of glycine doped polyaniline (PAni) nanofilms on silicon (Si) substrate was built and modified further with anti-atrazine antibodies. The herein developed immunosensor offered highly sensitive detection of atrazine with a low detection limit of 0.07 ng ml-1. The proposed biosensor was simple in design with excellent performance in terms of its sensitivity, stability and specificity. Highlights •Glycine doped PAni nanofilms have been electropolymerized on Silicon substrates. •Functionality of the above thin films provides opportunity to develop an immunosensing platform. •Highly sensitive and specific detection of atrazine has been realized over a wide concentration range with a LOD of 0.07 ng ml-1. Novelty statement Atrazine is a widely used pesticide in the agriculture sector. It is highly recommended to develop simple biosensing systems for enabling the prospect of routine monitoring. The present research for the first time proposes the design of a glycine doped PAni based simple and highly effective biosensor for the atrazine pesticide. The doping of glycine has easily generated functional groups on the nano-PAni material for further convenient immobilization of anti-atrazine antibodies. The proposed sensor can be highlighted with advantages like ease of fabrication, use of environment friendly functionalization agent, specificity, wide linearity, and good sensitivity with enhanced viability.

SiMa Cells for a Serotype Specific and Sensitive Cell-Based Neutralization Test for Botulinum Toxin A and E.

PubMed

Bak, Nicola; Rajagopal, Shalini; Stickings, Paul; Sesardic, Dorothea

2017-07-20

Botulinum toxins (BoNTs), of which there are seven serotypes, are among the most potent neurotoxins, with serotypes A, B and E causing human botulism. Antitoxins form the first line of treatment for botulism, and functional, highly sensitive in vitro methods for toxin neutralization are needed to replace the current in vivo methods used for determination of antitoxin potency. In this preliminary proof of concept study, we report the development of a neutralization test using the neuroblastoma SiMa cell line. The assay is serotype specific for either BoNT/A or BoNT/E, which both cleave unique sequences on SNAP-25 within SiMa cells. The end point is simple immunodetection of cleaved SNAP-25 from cell lysates with antibodies detecting only the newly exposed sequence on SNAP-25. Neutralizing antibodies prevent the toxin-induced cleavage of SNAP-25. The toxin neutralization assay, with an EC50 of ~2 mIU/mL determined with a standardized reference antiserum, is more sensitive than the mouse bioassays. Relevance was demonstrated with commercial and experimental antitoxins targeting different functional domains, and of known in vivo neutralizing activities. This is the first report describing a simple, specific, in vitro cell-based assay for the detection of neutralizing antibodies against BoNT/A and BoNT/E with a sensitivity exceeding that of the mouse bioassay.

SiMa Cells for a Serotype Specific and Sensitive Cell-Based Neutralization Test for Botulinum Toxin A and E

PubMed Central

Bak, Nicola; Rajagopal, Shalini; Stickings, Paul; Sesardic, Dorothea

2017-01-01

Botulinum toxins (BoNTs), of which there are seven serotypes, are among the most potent neurotoxins, with serotypes A, B and E causing human botulism. Antitoxins form the first line of treatment for botulism, and functional, highly sensitive in vitro methods for toxin neutralization are needed to replace the current in vivo methods used for determination of antitoxin potency. In this preliminary proof of concept study, we report the development of a neutralization test using the neuroblastoma SiMa cell line. The assay is serotype specific for either BoNT/A or BoNT/E, which both cleave unique sequences on SNAP-25 within SiMa cells. The end point is simple immunodetection of cleaved SNAP-25 from cell lysates with antibodies detecting only the newly exposed sequence on SNAP-25. Neutralizing antibodies prevent the toxin-induced cleavage of SNAP-25. The toxin neutralization assay, with an EC50 of ~2 mIU/mL determined with a standardized reference antiserum, is more sensitive than the mouse bioassays. Relevance was demonstrated with commercial and experimental antitoxins targeting different functional domains, and of known in vivo neutralizing activities. This is the first report describing a simple, specific, in vitro cell-based assay for the detection of neutralizing antibodies against BoNT/A and BoNT/E with a sensitivity exceeding that of the mouse bioassay. PMID:28726719

Development of a species-specific coproantigen ELISA for human Taenia solium taeniasis.

PubMed

Guezala, Maria-Claudia; Rodriguez, Silvia; Zamora, Humberto; Garcia, Hector H; Gonzalez, Armando E; Tembo, Alice; Allan, James C; Craig, Philip S

2009-09-01

Taenia solium causes human neurocysticercosis and is endemic in underdeveloped countries where backyard pig keeping is common. Microscopic fecal diagnostic methods for human T. solium taeniasis are not very sensitive, and Taenia saginata and Taenia solium eggs are indistinguishable under the light microscope. Coproantigen (CoAg) ELISA methods are very sensitive, but currently only genus (Taenia) specific. This paper describes the development of a highly species-specific coproantigen ELISA test to detect T. solium intestinal taeniasis. Sensitivity was maintained using a capture antibody of rabbit IgG against T. solium adult whole worm somatic extract, whereas species specificity was achieved by utilization of an enzyme-conjugated rabbit IgG against T. solium adult excretory-secretory (ES) antigen. A known panel of positive and negative human fecal samples was tested with this hybrid sandwich ELISA. The ELISA test gave 100% specificity and 96.4% sensitivity for T. solium tapeworm carriers (N = 28), with a J index of 0.96. This simple ELISA incorporating anti-adult somatic and anti-adult ES antibodies provides the first potentially species-specific coproantigen test for human T. solium taeniasis.

Green light may improve diagnostic accuracy of nailfold capillaroscopy with a simple digital videomicroscope.

PubMed

Weekenstroo, Harm H A; Cornelissen, Bart M W; Bernelot Moens, Hein J

2015-06-01

Nailfold capillaroscopy is a non-invasive and safe technique for the analysis of microangiopathologies. Imaging quality of widely used simple videomicroscopes is poor. The use of green illumination instead of the commonly used white light may improve contrast. The aim of the study was to compare the effect of green illumination with white illumination, regarding capillary density, the number of microangiopathologies, and sensitivity and specificity for systemic sclerosis. Five rheumatologists have evaluated 80 images; 40 images acquired with green light, and 40 images acquired with white light. A larger number of microangiopathologies were found in images acquired with green light than in images acquired with white light. This results in slightly higher sensitivity with green light in comparison with white light, without reducing the specificity. These findings suggest that green instead of white illumination may facilitate evaluation of capillaroscopic images obtained with a low-cost digital videomicroscope.

Noninvasive Tests Do Not Accurately Differentiate Nonalcoholic Steatohepatitis From Simple Steatosis: A Systematic Review and Meta-analysis.

PubMed

Verhaegh, Pauline; Bavalia, Roisin; Winkens, Bjorn; Masclee, Ad; Jonkers, Daisy; Koek, Ger

2018-06-01

Nonalcoholic fatty liver disease is a rapidly increasing health problem. Liver biopsy analysis is the most sensitive test to differentiate between nonalcoholic steatohepatitis (NASH) and simple steatosis (SS), but noninvasive methods are needed. We performed a systematic review and meta-analysis of noninvasive tests for differentiating NASH from SS, focusing on blood markers. We performed a systematic search of the PubMed, Medline and Embase (1990-2016) databases using defined keywords, limited to full-text papers in English and human adults, and identified 2608 articles. Two independent reviewers screened the articles and identified 122 eligible articles that used liver biopsy as reference standard. If at least 2 studies were available, pooled sensitivity (sens p ) and specificity (spec p ) values were determined using the Meta-Analysis Package for R (metafor). In the 122 studies analyzed, 219 different blood markers (107 single markers and 112 scoring systems) were identified to differentiate NASH from simple steatosis, and 22 other diagnostic tests were studied. Markers identified related to several pathophysiological mechanisms. The markers analyzed in the largest proportions of studies were alanine aminotransferase (sens p , 63.5% and spec p , 74.4%) within routine biochemical tests, adiponectin (sensp, 72.0% and spec p , 75.7%) within inflammatory markers, CK18-M30 (sens p , 68.4% and spec p , 74.2%) within markers of cell death or proliferation and homeostatic model assessment of insulin resistance (sens p , 69.0% and spec p , 72.7%) within the metabolic markers. Two scoring systems could also be pooled: the NASH test (differentiated NASH from borderline NASH plus simple steatosis with 22.9% sens p and 95.3% spec p ) and the GlycoNASH test (67.1% sens p and 63.8% spec p ). In the meta-analysis, we found no test to differentiate NASH from SS with a high level of pooled sensitivity and specificity (≥80%). However, some blood markers, when included in scoring systems in single studies, identified patients with NASH with ≥80% sensitivity and specificity. Replication studies and more standardized study designs are urgently needed. At present, no marker or scoring system can be recommended for use in clinical practice to differentiate NASH from simple steatosis. Copyright © 2018 AGA Institute. Published by Elsevier Inc. All rights reserved.

Understanding and comparisons of different sampling approaches for the Fourier Amplitudes Sensitivity Test (FAST)

PubMed Central

Xu, Chonggang; Gertner, George

2013-01-01

Fourier Amplitude Sensitivity Test (FAST) is one of the most popular uncertainty and sensitivity analysis techniques. It uses a periodic sampling approach and a Fourier transformation to decompose the variance of a model output into partial variances contributed by different model parameters. Until now, the FAST analysis is mainly confined to the estimation of partial variances contributed by the main effects of model parameters, but does not allow for those contributed by specific interactions among parameters. In this paper, we theoretically show that FAST analysis can be used to estimate partial variances contributed by both main effects and interaction effects of model parameters using different sampling approaches (i.e., traditional search-curve based sampling, simple random sampling and random balance design sampling). We also analytically calculate the potential errors and biases in the estimation of partial variances. Hypothesis tests are constructed to reduce the effect of sampling errors on the estimation of partial variances. Our results show that compared to simple random sampling and random balance design sampling, sensitivity indices (ratios of partial variances to variance of a specific model output) estimated by search-curve based sampling generally have higher precision but larger underestimations. Compared to simple random sampling, random balance design sampling generally provides higher estimation precision for partial variances contributed by the main effects of parameters. The theoretical derivation of partial variances contributed by higher-order interactions and the calculation of their corresponding estimation errors in different sampling schemes can help us better understand the FAST method and provide a fundamental basis for FAST applications and further improvements. PMID:24143037

Understanding and comparisons of different sampling approaches for the Fourier Amplitudes Sensitivity Test (FAST).

PubMed

Xu, Chonggang; Gertner, George

2011-01-01

Fourier Amplitude Sensitivity Test (FAST) is one of the most popular uncertainty and sensitivity analysis techniques. It uses a periodic sampling approach and a Fourier transformation to decompose the variance of a model output into partial variances contributed by different model parameters. Until now, the FAST analysis is mainly confined to the estimation of partial variances contributed by the main effects of model parameters, but does not allow for those contributed by specific interactions among parameters. In this paper, we theoretically show that FAST analysis can be used to estimate partial variances contributed by both main effects and interaction effects of model parameters using different sampling approaches (i.e., traditional search-curve based sampling, simple random sampling and random balance design sampling). We also analytically calculate the potential errors and biases in the estimation of partial variances. Hypothesis tests are constructed to reduce the effect of sampling errors on the estimation of partial variances. Our results show that compared to simple random sampling and random balance design sampling, sensitivity indices (ratios of partial variances to variance of a specific model output) estimated by search-curve based sampling generally have higher precision but larger underestimations. Compared to simple random sampling, random balance design sampling generally provides higher estimation precision for partial variances contributed by the main effects of parameters. The theoretical derivation of partial variances contributed by higher-order interactions and the calculation of their corresponding estimation errors in different sampling schemes can help us better understand the FAST method and provide a fundamental basis for FAST applications and further improvements.

Biochemical analysis of force-sensitive responses using a large-scale cell stretch device.

PubMed

Renner, Derrick J; Ewald, Makena L; Kim, Timothy; Yamada, Soichiro

2017-09-03

Physical force has emerged as a key regulator of tissue homeostasis, and plays an important role in embryogenesis, tissue regeneration, and disease progression. Currently, the details of protein interactions under elevated physical stress are largely missing, therefore, preventing the fundamental, molecular understanding of mechano-transduction. This is in part due to the difficulty isolating large quantities of cell lysates exposed to force-bearing conditions for biochemical analysis. We designed a simple, easy-to-fabricate, large-scale cell stretch device for the analysis of force-sensitive cell responses. Using proximal biotinylation (BioID) analysis or phospho-specific antibodies, we detected force-sensitive biochemical changes in cells exposed to prolonged cyclic substrate stretch. For example, using promiscuous biotin ligase BirA* tagged α-catenin, the biotinylation of myosin IIA increased with stretch, suggesting the close proximity of myosin IIA to α-catenin under a force bearing condition. Furthermore, using phospho-specific antibodies, Akt phosphorylation was reduced upon stretch while Src phosphorylation was unchanged. Interestingly, phosphorylation of GSK3β, a downstream effector of Akt pathway, was also reduced with stretch, while the phosphorylation of other Akt effectors was unchanged. These data suggest that the Akt-GSK3β pathway is force-sensitive. This simple cell stretch device enables biochemical analysis of force-sensitive responses and has potential to uncover molecules underlying mechano-transduction.

The use of sonographic subjective tumor assessment, IOTA logistic regression model 1, IOTA Simple Rules and GI-RADS system in the preoperative prediction of malignancy in women with adnexal masses.

PubMed

Koneczny, Jarosław; Czekierdowski, Artur; Florczak, Marek; Poziemski, Paweł; Stachowicz, Norbert; Borowski, Dariusz

2017-01-01

Sonography based methods with various tumor markers are currently used to discriminate the type of adnexal masses. To compare the predictive value of selected sonography-based models along with subjective assessment in ovarian cancer prediction. We analyzed data of 271 women operated because of adnexal masses. All masses were verified by histological examination. Preoperative sonography was performed in all patients and various predictive models includ¬ing IOTA group logistic regression model LR1 (LR1), IOTA simple ultrasound-based rules by IOTA (SR), GI-RADS and risk of malignancy index (RMI3) were used. ROC curves were constructed and respective AUC's with 95% CI's were compared. Of 271 masses 78 proved to be malignant including 6 borderline tumors. LR1 had sensitivity of 91.0%, specificity of 91.2%, AUC = 0.95 (95% CI: 0.92-0.98). Sensitivity for GI-RADS for 271 patients was 88.5% with specificity of 85% and AUC = 0.91 (95% CI: 0.88-0.95). Subjective assessment yielded sensitivity and specificity of 85.9% and 96.9%, respectively with AUC = 0.97 (95% CI: 0.94-0.99). SR were applicable in 236 masses and had sensitivity of 90.6% with specificity of 95.3% and AUC = 0.93 (95% CI 0.89-0.97). RMI3 was calculated only in 104 women who had CA125 available and had sensitivity of 55.3%, specificity of 94% and AUC = 0.85 (95% CI: 0.77-0.93). Although subjective assessment by the ultrasound expert remains the best current method of adnexal tumors preoperative discrimination, the simplicity and high predictive value favor the IOTA SR method, and when not applicable, the IOTA LR1 or GI-RADS models to be primarily and effectively used.

Multiplex detection of microRNAs by combining molecular beacon probes with T7 exonuclease-assisted cyclic amplification reaction.

PubMed

Liu, Yacui; Zhang, Jiangyan; Tian, Jingxiao; Fan, Xiaofei; Geng, Hao; Cheng, Yongqiang

2017-01-01

A simple, highly sensitive, and specific assay was developed for the homogeneous and multiplex detection of microRNAs (miRNAs) by combining molecular beacon (MB) probes and T7 exonuclease-assisted cyclic amplification. An MB probe with five base pairs in the stem region without special modification can effectively prevent the digestion by T7 exonuclease. Only in the presence of target miRNA is the MB probe hybridized with the target miRNA, and then digested by T7 exonuclease in the 5' to 3' direction. At the same time, the target miRNA is released and subsequently initiates the nuclease-assisted cyclic digestion process, generating enhanced fluorescence signal significantly. The results show that the combination of T7 exonuclease-assisted cyclic amplification reaction and MB probe possesses higher sensitivity for miRNA detection. Moreover, multiplex detection of miRNAs was successfully achieved by designing two MB probes labeled with FAM and Cy3, respectively. As a result, the method opens a new pathway for the sensitive and multiplex detection of miRNAs as well as clinical diagnosis. Graphical Abstract A simple, highly sensitive, and specific assay was developed for the detection of microRNAs by combining molecular beacon probes with T7 exonuclease-assisted cyclic amplification reaction.

The Mutation-Associated Neoantigen Functional Expansion of Specific T cells (MANAFEST) assay: a sensitive platform for monitoring antitumor immunity.

PubMed

Danilova, Ludmila; Anagnostou, Valsamo; Caushi, Justina X; Sidhom, John-William; Guo, Haidan; Chan, Hok Yee; Suri, Prerna; Tam, Ada J; Zhang, Jiajia; El Asmar, Margueritta; Marrone, Kristen A; Naidoo, Jarushka; Brahmer, Julie R; Forde, Patrick M; Baras, Alexander S; Cope, Leslie; Velculescu, Victor E; Pardoll, Drew; Housseau, Franck; Smith, Kellie N

2018-06-12

Mutation-associated neoantigens (MANAs) are a target of antitumor T-cell immunity. Sensitive, simple, and standardized assays are needed to assess the repertoire of functional MANA-specific T cells in oncology. Assays analyzing in vitro cytokine production such as ELISpot and intracellular cytokine staining (ICS) have been useful but have limited sensitivity in assessing tumor-specific T-cell responses and do not analyze antigen-specific T-cell repertoires. The FEST (Functional Expansion of Specific T cells) assay described herein integrates TCR sequencing of short-term, peptide-stimulated cultures with a bioinformatic platform to identify antigen-specific clonotypic amplifications. This assay can be adapted for all types of antigens, including mutation associated neoantigens (MANAs) via tumor exome-guided prediction of MANAs. Following in vitro identification by the MANAFEST assay, the MANA-specific CDR3 sequence can be used as a molecular barcode to detect and monitor the dynamics of these clonotypes in blood, tumor, and normal tissue of patients receiving immunotherapy. MANAFEST is compatible with high-throughput routine clinical and lab practices. Copyright ©2018, American Association for Cancer Research.

High-resolution melting analysis for bird sexing: a successful approach to molecular sex identification using different biological samples.

PubMed

Morinha, Francisco; Travassos, Paulo; Seixas, Fernanda; Santos, Nuno; Sargo, Roberto; Sousa, Luís; Magalhães, Paula; Cabral, João A; Bastos, Estela

2013-05-01

High-resolution melting (HRM) analysis is a very attractive and flexible advanced post-PCR method with high sensitivity/specificity for simple, fast and cost-effective genotyping based on the detection of specific melting profiles of PCR products. Next generation real-time PCR systems, along with improved saturating DNA-binding dyes, enable the direct acquisition of HRM data after quantitative PCR. Melting behaviour is particularly influenced by the length, nucleotide sequence and GC content of the amplicons. This method is expanding rapidly in several research areas such as human genetics, reproductive biology, microbiology and ecology/conservation of wild populations. Here we have developed a successful HRM protocol for avian sex identification based on the amplification of sex-specific CHD1 fragments. The melting curve patterns allowed efficient sexual differentiation of 111 samples analysed (plucked feathers, muscle tissues, blood and oral cavity epithelial cells) of 14 bird species. In addition, we sequenced the amplified regions of the CHD1 gene and demonstrated the usefulness of this strategy for the genotype discrimination of various amplicons (CHD1Z and CHD1W), which have small size differences, ranging from 2 bp to 44 bp. The established methodology clearly revealed the advantages (e.g. closed-tube system, high sensitivity and rapidity) of a simple HRM assay for accurate sex differentiation of the species under study. The requirements, strengths and limitations of the method are addressed to provide a simple guide for its application in the field of molecular sexing of birds. The high sensitivity and resolution relative to previous real-time PCR methods makes HRM analysis an excellent approach for improving advanced molecular methods for bird sexing. © 2013 Blackwell Publishing Ltd.

Venous glucose, serum lactate and base deficit as biochemical predictors of mortality in patients with polytrauma.

PubMed

Saad, Sameh; Mohamed, Naglaa; Moghazy, Amr; Ellabban, Gouda; El-Kamash, Soliman

2016-01-01

The trauma and injury severity score (TRISS) and Acute Physiology and Chronic Health Evaluation IV (APACHE IV) are accurate but complex. This study aimed to compare venous glucose, levels of serum lactate, and base deficit in polytraumatized patients as simple parameters to predict the mortality in these patients versus (TRISS) and (APACHE IV). This was a comparative cross-sectional study of 282 patients with polytrauma presented to the Emergency Department (ED). The best cut off value of TRISS probability of survival score for prediction of mortality among poly-traumatized patients was ≤90. APACHE IV demonstrated 67% sensitivity and 95% specificity at 95% CI at cut off point 99. The best cutoff value of Random Blood Sugar was >140 mg/dl, with 89% sensitivity, 49% specificity; base deficit was less than -5.6 with 64% sensitivity, 93% specificity; lactate was >2.6 mmol/L with 92%, sensitivity, 42% specificity. Venous glucose, serum lactate and base deficit are easy and rapid biochemical predictors of mortality in patients with polytrauma. These predictors could be used as TRISS and APACHE IV in predicting mortality.

ROC-ing along: Evaluation and interpretation of receiver operating characteristic curves.

PubMed

Carter, Jane V; Pan, Jianmin; Rai, Shesh N; Galandiuk, Susan

2016-06-01

It is vital for clinicians to understand and interpret correctly medical statistics as used in clinical studies. In this review, we address current issues and focus on delivering a simple, yet comprehensive, explanation of common research methodology involving receiver operating characteristic (ROC) curves. ROC curves are used most commonly in medicine as a means of evaluating diagnostic tests. Sample data from a plasma test for the diagnosis of colorectal cancer were used to generate a prediction model. These are actual, unpublished data that have been used to describe the calculation of sensitivity, specificity, positive predictive and negative predictive values, and accuracy. The ROC curves were generated to determine the accuracy of this plasma test. These curves are generated by plotting the sensitivity (true-positive rate) on the y axis and 1 - specificity (false-positive rate) on the x axis. Curves that approach closest to the coordinate (x = 0, y = 1) are more highly predictive, whereas ROC curves that lie close to the line of equality indicate that the result is no better than that obtained by chance. The optimum sensitivity and specificity can be determined from the graph as the point where the minimum distance line crosses the ROC curve. This point corresponds to the Youden index (J), a function of sensitivity and specificity used commonly to rate diagnostic tests. The area under the curve is used to quantify the overall ability of a test to discriminate between 2 outcomes. By following these simple guidelines, interpretation of ROC curves will be less difficult and they can then be interpreted more reliably when writing, reviewing, or analyzing scientific papers. Copyright © 2016 Elsevier Inc. All rights reserved.

[Transcutaneous electrical nervous stimulation in the prognosis of Bell's palsy].

PubMed

Sabag-Ruiz, Enrique; Osuna-Bernal, Janeth; Brito-Zurita, Olga Rosa; Gómez-Alcalá, Alejandro Vidal; Ornelas-Aguirre, José Manuel

2009-01-01

The peripheral face palsy (PFP) is the commonest acute cranial neuropathy. The PFP has a showy clinical pattern which contrasts with a favorable course. Our objective was to determine the sensitivity and specificity for the nervous excitability test (NET) with transcutaneous electrical nerve stimulation (TENS) and the time required to obtain face symmetry. An analytical cross-sectional study was made in 22 patients with PFP. The goal was the time (days) to obtain face symmetry. The sensitivity and specificity was carried out. A sensitivity and specificity of the NET was of 100 %. The correlation corrected by sex and age between both variables was 0.89. The average in days of recovery was smaller in those with a positive NET (p < 0.05) test. The test of nervous excitability for PFP with TENS is safe and simple to use in primary care and urgencies services.

A sensitive epitope-blocking ELISA for the detection of Chikungunya virus-specific antibodies in patients.

PubMed

Goh, Lucas Y H; Kam, Yiu-Wing; Metz, Stefan W; Hobson-Peters, Jody; Prow, Natalie A; McCarthy, Suzi; Smith, David W; Pijlman, Gorben P; Ng, Lisa F P; Hall, Roy A

2015-09-15

Chikungunya fever (CHIKF) has re-emerged as an arboviral disease that mimics clinical symptoms of other diseases such as dengue, malaria, as well as other alphavirus-related illnesses leading to problems with definitive diagnosis of the infection. Herein we describe the development and evaluation of a sensitive epitope-blocking ELISA (EB-ELISA) capable of specifically detecting anti-chikungunya virus (CHIKV) antibodies in clinical samples. The assay uses a monoclonal antibody (mAb) that binds an epitope on the E2 protein of CHIKV and does not exhibit cross-reactivity to other related alphaviruses. We also demonstrated the use of recombinant CHIK virus-like particles (VLPs) as a safe alternative antigen to infectious virions in the assay. Based on testing of 60 serum samples from patients in the acute or convalescent phase of CHIKV infection, the EB-ELISA provided us with 100% sensitivity, and exhibited 98.5% specificity when Ross River virus (RRV)- or Barmah Forest virus (BFV)-immune serum samples were included. This assay meets the public health demands of a rapid, robust, sensitive and specific, yet simple assay for specifically diagnosing CHIK-infections in humans. Copyright © 2015. Published by Elsevier B.V.

Novel approach based on one-tube nested PCR and a lateral flow strip for highly sensitive diagnosis of tuberculous meningitis.

PubMed

Sun, Yajuan; Chen, Jiajun; Li, Jia; Xu, Yawei; Jin, Hui; Xu, Na; Yin, Rui; Hu, Guohua

2017-01-01

Rapid and sensitive detection of Mycobacterium tuberculosis (M. Tb) in cerebrospinal fluid is crucial in the diagnosis of tuberculous meningitis (TBM), but conventional diagnostic technologies have limited sensitivity and specificity or are time-consuming. In this work, a novel, highly sensitive molecular diagnostic method, one-tube nested PCR-lateral flow strip test (OTNPCR-LFST), was developed for detecting M. tuberculosis. This one-tube nested PCR maintains the sensitivity of conventional two-step nested PCR and reduces both the chance of cross-contamination and the time required for analysis. The PCR product was detected by a lateral flow strip assay, which provided a basis for migration of the test to a point-of-care (POC) microfluidic format. The developed assay had an improved sensitivity compared with traditional PCR, and the limit of detection was up to 1 fg DNA isolated from M. tuberculosis. The assay was also specific for M. tuberculosis, and no cross-reactions were found in other non-target bacteria. The application of this technique to clinical samples was successfully evaluated, and OTNPCR-LFST showed 89% overall sensitivity and 100% specificity for TBM patients. This one-tube nested PCR-lateral flow strip assay is useful for detecting M. tuberculosis in TBM due to its rapidity, high sensitivity and simple manipulation.

Single strand DNA functionalized single wall carbon nanotubes as sensitive electrochemical labels for arsenite detection.

PubMed

Wang, Yonghong; Wang, Ping; Wang, Yiqiang; He, Xiaoxiao; Wang, Kemin

2015-08-15

In this work, a simple and sensitive electrochemical strategy for arsenite detection based on the ability of arsenite bound to single-strand DNA (ssDNA) and the signal transduction of single wall carbon nanotubes (SWCNTs) is developed. To realize this purpose, the ssDNA/SWCNTs complexes were formed at first by making ssDNA wrapped around SWCNTs via π-stacking. In the presence of arsenite, the arsenite could strongly bind with the G/T bases of ssDNA and decrease the π-π interaction between ssDNA and SWCNTs, resulting in a certain amount of ssDNA dissociating from the complexes. The separated SWCNTs were selectively assembled on the self-assembled monolayer (SAM) modified Au electrode. Then the SWCNTs onto the SAM-modified Au electrode substantially restored heterogeneous electron transfer that was almost totally blocked by the SAM. The assembled SWCNTs could generate a considerably sensitive and specific tactic for signal transduction, which was related to the concentration of the arsenite. Through detecting the currents mediated by SWCNTs, a linear response to concentration of arsenite ranging from 0.5 to 10ppb and a detection limit of 0.5ppb was readily achieved with desirable specificity and sensitivity. Such a SWCNTs-based biosensor creates a simple, sensitive, nonradioactive route for detection of arsenite. In addition, this demonstration provides a new approach to fabrication of stable biosensors with favorable electrochemical properties believed to be appealing to electroanalytical applications. Copyright © 2015 Elsevier B.V. All rights reserved.

ADHD Diagnosis: As Simple As Administering a Questionnaire or a Complex Diagnostic Process?

PubMed

Parker, Ashton; Corkum, Penny

2016-06-01

The present study investigated the validity of using the Conners' Teacher and Parent Rating Scales (CTRS/CPRS) or semistructured diagnostic interviews (Parent Interview for Child Symptoms and Teacher Telephone Interview) to predict a best-practices clinical diagnosis of ADHD. A total of 279 children received a clinical diagnosis based on a best-practices comprehensive assessment (including diagnostic parent and teacher interviews, collection of historical information, rating scales, classroom observations, and a psychoeducational assessment) at a specialty ADHD Clinic in Truro, Nova Scotia, Canada. Sensitivity and specificity with clinical diagnosis were determined for the ratings scales and diagnostic interviews. Sensitivity and specificity values were high for the diagnostic interviews (91.8% and 70.7%, respectively). However, while sensitivity of the CTRS/CPRS was relatively high (83.5%), specificity was poor (35.7%). The low specificity of the CPRS/CTRS is not sufficient to be used alone to diagnose ADHD. (J. of Att. Dis. 2016; 20(6) 478-486). © The Author(s) 2013.

Colorimetric detection of Cucumber green mottle mosaic virus using unmodified gold nanoparticles as colorimetric probes.

PubMed

Wang, Lin; Liu, Zhanmin; Xia, Xueying; Yang, Cuiyun; Huang, Junyi; Wan, Sibao

2017-05-01

Cucumber green mottle mosaic virus (CGMMV)causes a severe mosaic symptom of watermelon and cucumber, and can be transmitted via infected cucumber seeds, leaves and soil. It remains a challenge to detect this virus to prevent its introduction and infection and spread in fields. For this purpose, a simple and sensitive label-free colorimetric detection method for CGMMV has been developed with unmodified gold nanoparticles (AuNPs) as colorimetric probes. The method is based on the finding that the presence of RT-PCR target products of CGMMV and species-specific probes results in color change of AuNPs from red to blue after NaCl induction. Normally, species-specific probes attach to the surface of AuNPs and thereby increasing their resistance to NaCl-induced aggregation. The concentration of sodium, probes in the reaction system and evaluation of specificity and sensitivity of a novel assay, visual detection of Cucumber green mottle mosaic virus using unmodified AuNPs has been carried out with simple preparation of samples in our study. Through this assay, as low as 30pg/μL of CGMMV RNA was thus detected visually, by the naked eye, without the need for any sophisticated, expensive instrumentation and biochemical reagents. The specificity was 100% and exhibited good reproducibility in our assays. The results note that this assay is highly species-specific, simple, low-cost, and visual for easy detection of CGMMV in plant tissues. Therefore, visual assay is a potentially useful tool for middle or small-scales corporations and entry-exit inspection and quarantine bureau to detect CGMMV in cucumber seeds or plant tissues. Copyright © 2017 Elsevier B.V. All rights reserved.

[Definition of the specificity of DNA-methyltransferase M.Bsc4I in cell lysate by blocking of restriction endonucleases and computer modeling].

PubMed

Dedkov, V S

2009-01-01

The specificity of DNA-methyltransferase M.Bsc4I was defined in cellular lysate of Bacillus schlegelii 4. For this purpose, we used methylation sensitivity of restriction endonucleases, and also modeling of methylation. The modeling consisted in editing sequences of DNA using replacements of methylated bases and their complementary bases. The substratum DNA processed by M.Bsc4I also were used for studying sensitivity of some restriction endonucleases to methylation. Thus, it was shown that M.Bsc4I methylated 5'-Cm4CNNNNNNNGG-3' and the overlapped dcm-methylation blocked its activity. The offered approach can appear universal enough and simple for definition of specificity of DNA-methyltransferases.

Selective advantage of resistant strains at trace levels of antibiotics: a simple and ultrasensitive color test for detection of antibiotics and genotoxic agents.

PubMed

Liu, Anne; Fong, Amie; Becket, Elinne; Yuan, Jessica; Tamae, Cindy; Medrano, Leah; Maiz, Maria; Wahba, Christine; Lee, Catherine; Lee, Kim; Tran, Katherine P; Yang, Hanjing; Hoffman, Robert M; Salih, Anya; Miller, Jeffrey H

2011-03-01

Many studies have examined the evolution of bacterial mutants that are resistant to specific antibiotics, and many of these focus on concentrations at and above the MIC. Here we ask for the minimum concentration at which existing resistant mutants can outgrow sensitive wild-type strains in competition experiments at antibiotic levels significantly below the MIC, and we define a minimum selective concentration (MSC) in Escherichia coli for two antibiotics, which is near 1/5 of the MIC for ciprofloxacin and 1/20 of the MIC for tetracycline. Because of the prevalence of resistant mutants already in the human microbiome, allowable levels of antibiotics to which we are exposed should be below the MSC. Since this concentration often corresponds to low or trace levels of antibiotics, it is helpful to have simple tests to detect such trace levels. We describe a simple ultrasensitive test for detecting the presence of antibiotics and genotoxic agents. The test is based on the use of chromogenic proteins as color markers and the use of single and multiple mutants of Escherichia coli that have greatly increased sensitivity to either a wide range of antibiotics or specific antibiotics, antibiotic families, and genotoxic agents. This test can detect ciprofloxacin at 1/75 of the MIC.

Rapid, simple and direct detection of Meloidogyne hapla from infected root galls using loop-mediated isothermal amplification combined with FTA technology

PubMed Central

Peng, Huan; Long, Haibo; Huang, Wenkun; Liu, Jing; Cui, Jiangkuan; Kong, Lingan; Hu, Xianqi; Gu, Jianfeng; Peng, Deliang

2017-01-01

The northern root-knot nematode (Meloidogyne hapla) is a damaging nematode that has caused serious economic losses worldwide. In the present study, a sensitive, simple and rapid method was developed for detection of M. hapla in infested plant roots by combining a Flinders Technology Associates (FTA) card with loop-mediated isothermal amplification (LAMP). The specific primers of LAMP were designed based on the distinction of internal transcribed spacer (ITS) sequences between M. hapla and other Meloidogyne spp. The LAMP assay can detect nematode genomic DNA at concentrations low to 1/200 000, which is 100 times more sensitive than conventional PCR. The LAMP was able to highly specifically distinguish M. hapla from other closely related nematode species. Furthermore, the advantages of the FTA-LAMP assay to detect M. hapla were demonstrated by assaying infected root galls that were artificially inoculated. In addition, M. hapla was successfully detected from six of forty-two field samples using FTA-LAMP technology. This study was the first to provide a simple diagnostic assay for M. hapla using the LAMP assay combined with FTA technology. In conclusion, the new FTA-LAMP assay has the potential for diagnosing infestation in the field and managing the pathogen M. hapla. PMID:28368036

Rapid, simple and direct detection of Meloidogyne hapla from infected root galls using loop-mediated isothermal amplification combined with FTA technology.

PubMed

Peng, Huan; Long, Haibo; Huang, Wenkun; Liu, Jing; Cui, Jiangkuan; Kong, Lingan; Hu, Xianqi; Gu, Jianfeng; Peng, Deliang

2017-04-03

The northern root-knot nematode (Meloidogyne hapla) is a damaging nematode that has caused serious economic losses worldwide. In the present study, a sensitive, simple and rapid method was developed for detection of M. hapla in infested plant roots by combining a Flinders Technology Associates (FTA) card with loop-mediated isothermal amplification (LAMP). The specific primers of LAMP were designed based on the distinction of internal transcribed spacer (ITS) sequences between M. hapla and other Meloidogyne spp. The LAMP assay can detect nematode genomic DNA at concentrations low to 1/200 000, which is 100 times more sensitive than conventional PCR. The LAMP was able to highly specifically distinguish M. hapla from other closely related nematode species. Furthermore, the advantages of the FTA-LAMP assay to detect M. hapla were demonstrated by assaying infected root galls that were artificially inoculated. In addition, M. hapla was successfully detected from six of forty-two field samples using FTA-LAMP technology. This study was the first to provide a simple diagnostic assay for M. hapla using the LAMP assay combined with FTA technology. In conclusion, the new FTA-LAMP assay has the potential for diagnosing infestation in the field and managing the pathogen M. hapla.

A rapid and ultrasensitive SERRS assay for histidine and tyrosine based on azo coupling.

PubMed

Sui, Huimin; Wang, Yue; Yu, Zhi; Cong, Qian; Han, Xiao Xia; Zhao, Bing

2016-10-01

A simple and highly sensitive surface-enhanced resonance Raman scattering (SERRS)-based approach coupled with azo coupling reaction has been put forward for quantitative analysis of histidine and tyrosine. The SERRS-based assay is simple and rapid by mixing the azo reaction products with silver nanoparticles (AgNPs) for measurements within 2min. The limits of detection (LODs) of the method are as low as 4.33×10(-11) and 8.80×10(-11)M for histidine and tyrosine, respectively. Moreover, the SERRS fingerprint information specific to corresponding amino acids guarantees the selective detection for the target histidine and tyrosine. The results from serum indicated the potential application of the proposed approach into biological samples. Compared with the methods ever reported, the main advantages of this methodology are simpleness, rapidity without time-consuming separation or pretreatment steps, high sensitivity, selectivity and the potential for determination of other molecules containing imidazole or phenol groups. Copyright © 2016 Elsevier B.V. All rights reserved.

A rapid and simple method of detection of Blepharisma japonicum using PCR and immobilisation on FTA paper

PubMed Central

Hide, Geoff; Hughes, Jacqueline M; McNuff, Robert

2003-01-01

Background The rapid expansion in the availability of genome and DNA sequence information has opened up new possibilities for the development of methods for detecting free-living protozoa in environmental samples. The protozoan Blepharisma japonicum was used to investigate a rapid and simple detection system based on polymerase chain reaction amplification (PCR) from organisms immobilised on FTA paper. Results Using primers designed from the α-tubulin genes of Blepharisma, specific and sensitive detection to the equivalent of a single Blepharisma cell could be achieved. Similar detection levels were found using water samples, containing Blepharisma, which were dried onto Whatman FTA paper. Conclusion This system has potential as a sensitive convenient detection system for Blepharisma and could be applied to other protozoan organisms. PMID:14516472

ZnO Hierarchical Nanostructure Photoanode in a CdS Quantum Dot-Sensitized Solar Cell

PubMed Central

Liu, Huan; Zhang, Gengmin; Sun, Wentao; Shen, Ziyong; Shi, Mingji

2015-01-01

A hierarchical array of ZnO nanocones covered with ZnO nanospikes was hydrothermally fabricated and employed as the photoanode in a CdS quantum dot-sensitized solar cell (QDSSC). This QDSSC outperformed the QDSSC based on a simple ZnO nanocone photoanode in all the four principal photovoltaic parameters. Using the hierarchical photoanode dramatically increased the short circuit current density and also slightly raised the open circuit voltage and the fill factor. As a result, the conversion efficiency of the QDSSC based on the hierarchical photoanode was more than twice that of the QDSSC based on the simple ZnO nanocone photoanode. This improvement is attributable to both the enlarged specific area of the photoanode and the reduction in the recombination of the photoexcited electrons. PMID:26379268

Novel fabrication of flexible graphene-based chemical sensors with heaters using soft lithographic patterning method.

PubMed

Jung, Min Wook; Myung, Sung; Song, Wooseok; Kang, Min-A; Kim, Sung Ho; Yang, Cheol-Soo; Lee, Sun Sook; Lim, Jongsun; Park, Chong-Yun; Lee, Jeong-O; An, Ki-Seok

2014-08-27

We have fabricated graphene-based chemical sensors with flexible heaters for the highly sensitive detection of specific gases. We believe that increasing the temperature of the graphene surface significantly enhanced the electrical signal change of the graphene-based channel, and reduced the recovery time needed to obtain a normal state of equilibrium. In addition, a simple and efficient soft lithographic patterning process was developed via surface energy modification for advanced, graphene-based flexible devices, such as gas sensors. As a proof of concept, we demonstrated the high sensitivity of NO2 gas sensors based on graphene nanosheets. These devices were fabricated using a simple soft-lithographic patterning method, where flexible graphene heaters adjacent to the channel of sensing graphene were utilized to control graphene temperature.

Biomimetic self-templating optical structures fabricated by genetically engineered M13 bacteriophage.

PubMed

Kim, Won-Geun; Song, Hyerin; Kim, Chuntae; Moon, Jong-Sik; Kim, Kyujung; Lee, Seung-Wuk; Oh, Jin-Woo

2016-11-15

Here, we describe a highly sensitive and selective surface plasmon resonance sensor system by utilizing self-assembly of genetically engineered M13 bacteriophage. About 2700 copies of genetically expressed peptide copies give superior selectivity and sensitivity to M13 phage-based SPR sensor. Furthermore, the sensitivity of the M13 phage-based SPR sensor was enhanced due to the aligning of receptor matrix in specific direction. Incorporation of specific binding peptide (His Pro Gln: HPQ) gives M13 bacteriophage high selectivity for the streptavidin. Our M13 phage-based SPR sensor takes advantage of simplicity of self-assembly compared with relatively complex photolithography techniques or chemical conjugations. Additionally, designed structure which is composed of functionalized M13 bacteriophage can simultaneously improve the sensitivity and selectivity of SPR sensor evidently. By taking advantages of the genetic engineering and self-assembly, we propose the simple method for fabricating novel M13 phage-based SPR sensor system which has a high sensitivity and high selectivity. Copyright © 2016 Elsevier B.V. All rights reserved.

Aptamer-aided target capturing with biocatalytic metal deposition: an electrochemical platform for sensitive detection of cancer cells.

PubMed

Yi, Zi; Li, Xiao-Yan; Gao, Qing; Tang, Li-Juan; Chu, Xia

2013-04-07

A novel aptamer biosensor for cancer cell assay has been reported on the basis of ultrasensitive electrochemical detection. Cancer cell capturing is first accomplished via aptamer-aided recognition, and the cell-aptamer binding events then mediate an alkaline phosphatase-catalyzed silver deposition reaction which can be probed by electrochemical detection. Following biocatalytic silver deposition, an efficient amplification approach for sensitive electrochemical measurements is demonstrated, for cell detection with high sensitivity. Ramos cell are used as a model case, a typical biomarker of the acute blood cell cancer, Burkitt's lymphoma. The results reveal that the developed technique displays desirable selectivity in Ramos cell discrimination, and linear response range from 10 to 10(6) cells with a detection limit as low as 10 cells. Due to the simple procedures, label-free and electrochemistry based detection format, this technique is simple and cost-effective, and exhibits excellent compatibility with miniaturization technologies. The electrochemical cell detection strategy may create an intrinsically specific and sensitive platform for cancer cell assay and associated studies.

Microarray-based IgE detection in tears of patients with vernal keratoconjunctivitis.

PubMed

Leonardi, Andrea; Borghesan, Franco; Faggian, Diego; Plebani, Mario

2015-11-01

A specific allergen sensitization can be demonstrated in approximately half of the vernal keratoconjunctivitis (VKC) patients by conventional allergic tests. The measurement of specific IgE in tears using a multiplex allergen microarray may offer advantages to identify local sensitization to a specific allergen. In spring-summer 2011, serum and tears samples were collected from 10 active VKC patients (three females, seven males) and 10 age-matched normal subjects. Skin prick test, symptoms score and full ophthalmological examination were performed. Specific serum and tear IgE were assayed using ImmunoCAP ISAC, a microarray containing 103 components derived from 47 allergens. Normal subjects resulted negative for the presence of specific IgE both in serum and in tears. Of the 10 VKC patients, six resulted positive to specific IgE in serum and/or tears. In three of these six patients, specific IgE was found positive only in tears. Cross-reactivity between specific markers was found in three patients. Grass, tree, mites, animal but also food allergen-specific IgE were found in tears. Conjunctival provocation test performed out of season confirmed the specific local conjunctival reactivity. Multiple specific IgE measurements with single protein allergens using a microarray technique in tear samples are a useful, simple and non-invasive diagnostic tool. ImmunoCAP ISAC detects allergen sensitization at component level and adds important information by defining both cross- and co-sensitization to a large variety of allergen molecules. The presence of specific IgE only in tears of VKC patients reinforces the concept of possible local sensitization. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Indication for Computed Tomography Scan in Shoulder Instability: Sensitivity and Specificity of Standard Radiographs to Predict Bone Defects After Traumatic Anterior Glenohumeral Instability.

PubMed

Delage Royle, Audrey; Balg, Frédéric; Bouliane, Martin J; Canet-Silvestri, Fanny; Garant-Saine, Laurianne; Sheps, David M; Lapner, Peter; Rouleau, Dominique M

2017-10-01

Quantifying glenohumeral bone loss is key in preoperative surgical planning for a successful Bankart repair. Simple radiographs can accurately measure bone defects in cases of recurrent shoulder instability. Cohort study (diagnosis); Level of evidence, 2. A true anteroposterior (AP) view, alone and in combination with an axillary view, was used to evaluate the diagnostic properties of radiographs compared with computed tomography (CT) scan, the current gold standard, to predict significant bone defects in 70 patients. Sensitivity, specificity, and positive and negative predictive values were evaluated and compared. Detection of glenoid bone loss on plain film radiographs, with and without axillary view, had a sensitivity of 86% for both views and a specificity of 73% and 64% with and without the axillary view, respectively. For detection of humeral bone loss, the sensitivity was 8% and 17% and the specificity was 98% and 91% with and without the axillary view, respectively. Regular radiographs would have missed 1 instance of significant bone loss on the glenoid side and 20 on the humeral side. Interobserver reliabilities were moderate for glenoid detection (κ = 0.473-0.503) and poor for the humeral side (κ = 0.278-0.336). Regular radiographs showed suboptimal sensitivity, specificity, and reliability. Therefore, CT scan should be considered in the treatment algorithm for accurate quantification of bone loss to prevent high rates of recurrent instability.

The Optimal Cut-Off Value of Neutrophil-to-Lymphocyte Ratio for Predicting Prognosis in Adult Patients with Henoch–Schönlein Purpura

PubMed Central

Park, Chan Hyuk; Han, Dong Soo; Jeong, Jae Yoon; Eun, Chang Soo; Yoo, Kyo-Sang; Jeon, Yong Cheol; Sohn, Joo Hyun

2016-01-01

Background The development of gastrointestinal (GI) bleeding and end-stage renal disease (ESRD) can be a concern in the management of Henoch–Schönlein purpura (HSP). We aimed to evaluate whether the neutrophil-to-lymphocyte ratio (NLR) is associated with the prognosis of adult patients with HSP. Methods Clinical data including the NLR of adult patients with HSP were retrospectively analyzed. Patients were classified into three groups as follows: (a) simple recovery, (b) wax & wane without GI bleeding, and (c) development of GI bleeding. The optimal cut-off value was determined using a receiver operating characteristics curve and the Youden index. Results A total of 66 adult patients were enrolled. The NLR was higher in the GI bleeding group than in the simple recovery or wax & wane group (simple recovery vs. wax & wane vs. GI bleeding; median [IQR], 2.32 [1.61–3.11] vs. 3.18 [2.16–3.71] vs. 7.52 [4.91–10.23], P<0.001). For the purpose of predicting simple recovery, the optimal cut-off value of NLR was 3.18, and the sensitivity and specificity were 74.1% and 75.0%, respectively. For predicting development of GI bleeding, the optimal cut-off value was 3.90 and the sensitivity and specificity were 87.5% and 88.6%, respectively. Conclusions The NLR is useful for predicting development of GI bleeding as well as simple recovery without symptom relapse. Two different cut-off values of NLR, 3.18 for predicting an easy recovery without symptom relapse and 3.90 for predicting GI bleeding can be used in adult patients with HSP. PMID:27073884

Gelatin-modified gold nanoparticles for direct detection of urinary total gelatinase activity: Diagnostic value in bladder cancer.

PubMed

Nossier, Ahmed I; Mohammed, Ola S; Fakhr El-Deen, Rasha R; Zaghloul, Ashraf S; Eissa, Sanaa

2016-12-01

Matrix metalloproteinases (MMPs), in particularly gelatinases (MMP-2 and MMP-9) were reported as urinary markers of bladder cancer. In this work, we developed a simple colorimetric gold nanoparticle (AuNP) assay for rapid and sensitive detection of urinary total gelatinase activity based on the surface plasmon resonance (SPR) property of AuNPs. Gelatin-modified AuNPs were stably suspended in solution even upon addition of an aggregation inducer as 6-mercaptohexan-1-ol (6-MCH). Gelatinases digest gelatin capping. Subsequently, addition of 6-MCH leads to AuNPs aggregation with red to blue color shift. In a pilot study, results of the developed AuNP assay were consistent with zymography for qualitative detection of urinary total gelatinase activity. The sensitivity and specificity of both assays were 80% and 90.9% respectively. The absorption ratios, A 625 /A 530 of the reacted AuNP solutions were used to quantify the total gelatinase concentration. The best cut off value was 0.01895ng/μg protein, at which the sensitivity was 87.5% and the specificity was 86.4%. The developed AuNP assay is simple, low-cost and can aid non-invasive diagnosis of bladder cancer. Copyright © 2016 Elsevier B.V. All rights reserved.

Development of a cyclic voltammetry method for the detection of Clostridium novyi in black disease.

PubMed

Liu, L L; Jiang, D N; Xiang, G M; Liu, C; Yu, J C; Pu, X Y

2014-03-17

Black disease is an acute disease of sheep and cattle. The pathogen is the obligate anaerobe, Clostridium novyi. Due to difficulties of anaerobic culturing in the country or disaster sites, a simple, rapid, and sensitive method is required. In this study, an electrochemical method, the cyclic voltammetry method, basing on loop-mediated isothermal amplification (LAMP), electrochemical ion bonding (positive dye, methylene blue), was introduced. DNA extracted from C. novyi specimens was amplified through the LAMP reaction. Then the products combined were with methylene blue, which lead to a reduction in the oxidation peak current (ipA) and the reduction peak current (ipC) of the cyclic voltammetry. The changes of ipA/ipC were real-time measured by special designed electrode, so the DNA was quantitatively detected. The results displayed that this electrochemical detection of C. novyi could be completed in 1-2 h with the lowest bacterial concentration of 10(2) colony forming units/mL, and high accuracy (96.5%), sensitivity (96%), and specificity (97%) compared to polymerase chain reation. The cyclic voltammetry method was a simple and fast method, with high sensitivity and high specificity, and has great potential to be a usable molecular tool for fast diagnosis of Black disease.

Simple Electrolyzer Model Development for High-Temperature Electrolysis System Analysis Using Solid Oxide Electrolysis Cell

DOE Office of Scientific and Technical Information (OSTI.GOV)

JaeHwa Koh; DuckJoo Yoon; Chang H. Oh

2010-07-01

An electrolyzer model for the analysis of a hydrogen-production system using a solid oxide electrolysis cell (SOEC) has been developed, and the effects for principal parameters have been estimated by sensitivity studies based on the developed model. The main parameters considered are current density, area specific resistance, temperature, pressure, and molar fraction and flow rates in the inlet and outlet. Finally, a simple model for a high-temperature hydrogen-production system using the solid oxide electrolysis cell integrated with very high temperature reactors is estimated.

Novel approach based on one-tube nested PCR and a lateral flow strip for highly sensitive diagnosis of tuberculous meningitis

PubMed Central

Sun, Yajuan; Chen, Jiajun; Li, Jia; Xu, Yawei; Jin, Hui; Xu, Na; Yin, Rui

2017-01-01

Rapid and sensitive detection of Mycobacterium tuberculosis (M. Tb) in cerebrospinal fluid is crucial in the diagnosis of tuberculous meningitis (TBM), but conventional diagnostic technologies have limited sensitivity and specificity or are time-consuming. In this work, a novel, highly sensitive molecular diagnostic method, one-tube nested PCR-lateral flow strip test (OTNPCR-LFST), was developed for detecting M. tuberculosis. This one-tube nested PCR maintains the sensitivity of conventional two-step nested PCR and reduces both the chance of cross-contamination and the time required for analysis. The PCR product was detected by a lateral flow strip assay, which provided a basis for migration of the test to a point-of-care (POC) microfluidic format. The developed assay had an improved sensitivity compared with traditional PCR, and the limit of detection was up to 1 fg DNA isolated from M. tuberculosis. The assay was also specific for M. tuberculosis, and no cross-reactions were found in other non-target bacteria. The application of this technique to clinical samples was successfully evaluated, and OTNPCR-LFST showed 89% overall sensitivity and 100% specificity for TBM patients. This one-tube nested PCR-lateral flow strip assay is useful for detecting M. tuberculosis in TBM due to its rapidity, high sensitivity and simple manipulation. PMID:29084241

Predictors of neonatal sepsis in developing countries.

PubMed

Weber, Martin W; Carlin, John B; Gatchalian, Salvacion; Lehmann, Deborah; Muhe, Lulu; Mulholland, E Kim

2003-08-01

Neonatal infections are a major cause of death worldwide. Simple procedures for identifying infants with infection that need referral for treatment are therefore of major public health importance. We investigated 3303 infants <2 months of age presenting with illness to health facilities in Ethiopia, The Gambia, Papua New Guinea and The Philippines, using a standardized approach. Historical factors and clinical signs predicting sepsis, meningitis, hypoxemia, deaths and an ordinal scale indicating severe disease were investigated by logistic regression, and the performance of simple combination rules was explored. In multivariable analysis, reduced feeding ability, no spontaneous movement, temperature >38 degrees C, being drowsy/unconscious, a history of a feeding problem, history of change in activity, being agitated, the presence of lower chest wall indrawing, respiratory rate >60 breaths/min, grunting, cyanosis, a history of convulsions, a bulging fontanel and slow digital capillary refill were independent predictors of severe disease. The presence of any 1 of these 14 signs had a sensitivity for severe disease (defined as sepsis, meningitis, hypoxemia, or radiologically proven pneumonia) of 87% and a specificity of 54%. More stringent combinations, such as demanding 2 signs from the list, resulted in a considerable loss of sensitivity. By contrast only slight loss of sensitivity and considerable gain of specificity resulted from reducing the list to 9 signs. Requiring the presence of fever and any other sign produced a diagnostic rule with extremely low sensitivity (25%). Physical signs can be used to identify young infants at risk of severe disease, however with limited specificity, resulting in large numbers of unnecessary referrals. Further studies are required to validate and refine the prediction of severe disease, especially in the first week of life, but there appear to be limits on the accuracy of prediction that is achievable.

Reading Angles in Maps

ERIC Educational Resources Information Center

Izard, Véronique; O'Donnell, Evan; Spelke, Elizabeth S.

2014-01-01

Preschool children can navigate by simple geometric maps of the environment, but the nature of the geometric relations they use in map reading remains unclear. Here, children were tested specifically on their sensitivity to angle. Forty-eight children (age 47:15-53:30 months) were presented with fragments of geometric maps, in which angle sections…

Development of one-step Loop-Mediated Isothermal Amplification (LAMP) for the detection of norovirus in oysters

USDA-ARS?s Scientific Manuscript database

The aim of this study was to develop a simple and rapid technique for detecting human norovirus (NoV). The loop-mediated isothermal amplification (LAMP) technique was evaluated and found to be sensitive, highly specific, and useful for routine oyster testing. Reverse transcription-LAMP (RT-LAMP) pri...

Universal absolute quantification of biomolecules using element mass spectrometry and generic standards.

PubMed

Calderón-Celis, Francisco; Sanz-Medel, Alfredo; Encinar, Jorge Ruiz

2018-01-23

We present a novel and highly sensitive ICP-MS approach for absolute quantification of all important target biomolecule containing P, S, Se, As, Br, and/or I (e.g., proteins and phosphoproteins, metabolites, pesticides, drugs), under the same simple instrumental conditions and without requiring any specific and/or isotopically enriched standard.

Chronic pesticide poisoning from persistent low-dose exposures in Ecuadorean floriculture workers: toward validating a low-cost test battery.

PubMed

Breilh, Jaime; Pagliccia, Nino; Yassi, Annalee

2012-01-01

Chronic pesticide poisoning is difficult to detect. We sought to develop a low-cost test battery for settings such as Ecuador's floriculture industry. First we had to develop a case definition; as with all occupational diseases a case had to have both sufficient effective dose and associated health effects. For the former, using canonical discriminant analysis, we found that adding measures of protection and overall environmental stressors to occupational category and duration of exposure was useful. For the latter, factor analysis suggested three distinct manifestations of pesticide poisoning. We then determined sensitivity and specificity of various combinations of symptoms and simple neurotoxicity tests from the Pentox questionnaire, and found that doing so increased sensitivity and specificity compared to use of acethylcholinesterase alone--the current screening standard. While sensitivity and specificity varied with different case definitions, our results support the development of a low-cost test battery for screening in such settings.

Advanced yellow fever virus genome detection in point-of-care facilities and reference laboratories.

PubMed

Domingo, Cristina; Patel, Pranav; Yillah, Jasmin; Weidmann, Manfred; Méndez, Jairo A; Nakouné, Emmanuel Rivalyn; Niedrig, Matthias

2012-12-01

Reported methods for the detection of the yellow fever viral genome are beset by limitations in sensitivity, specificity, strain detection spectra, and suitability to laboratories with simple infrastructure in areas of endemicity. We describe the development of two different approaches affording sensitive and specific detection of the yellow fever genome: a real-time reverse transcription-quantitative PCR (RT-qPCR) and an isothermal protocol employing the same primer-probe set but based on helicase-dependent amplification technology (RT-tHDA). Both assays were evaluated using yellow fever cell culture supernatants as well as spiked and clinical samples. We demonstrate reliable detection by both assays of different strains of yellow fever virus with improved sensitivity and specificity. The RT-qPCR assay is a powerful tool for reference or diagnostic laboratories with real-time PCR capability, while the isothermal RT-tHDA assay represents a useful alternative to earlier amplification techniques for the molecular diagnosis of yellow fever by field or point-of-care laboratories.

Loop-mediated isothermal amplification for detection of Staphylococcus aureus in dairy cow suffering from mastitis.

PubMed

Tie, Zhang; Chunguang, Wang; Xiaoyuan, Wei; Xinghua, Zhao; Xiuhui, Zhong

2012-01-01

To develop a rapid detection method of Staphylococcus aureus using loop-mediated isothermal amplification (LAMP), four specific primers were designed according to six distinct sequences of the nuc gene. In addition, the specificity and sensitivity of LAMP were verified and compared with those of PCR. Results showed that the LAMP reaction was completed within 45 min at 62.5°C, and ladder bands were appeared in LAMP products analyzed by gel electrophoresis. After adding 1x SYBR Green l, the positive reaction tube showed green color and the negative reaction tube remained orange, indicating that the LAMP has high specificity. The minimal detectable concentration of LAMP was 1 × 10² CFU/mL and that of PCR was 1 × 10⁴ CFU/mL, indicating that the LAMP was 100 times more sensitive than the PCR. The LAMP method for detection of Staphylococcus aureus has many advantages, such as simple operation, high sensitivity, high specificity, and rapid analysis. Therefore, this method is more suitable for the rapid on-site detection of Staphylococcus aureus.

Detection of prostate-specific antigen with biomolecule-gated AlGaN/GaN high electron mobility transistors

NASA Astrophysics Data System (ADS)

Li, Jia-dong; Cheng, Jun-jie; Miao, Bin; Wei, Xiao-wei; Xie, Jie; Zhang, Jin-cheng; Zhang, Zhi-qiang; Wu, Dong-min

2014-07-01

In order to improve the sensitivity of AlGaN/GaN high electron mobility transistor (HEMT) biosensors, a simple biomolecule-gated AlGaN/GaN HEMT structure was designed and successfully fabricated for prostate specific antigen (PSA) detection. UV/ozone was used to oxidize the GaN surface and then a 3-aminopropyl trimethoxysilane (APTES) self-assembled monolayer was bound to the sensing region. This monolayer serves as a binding layer for attachment of the prostate specific antibody (anti-PSA). The biomolecule-gated AlGaN/GaN HEMT sensor shows a rapid and sensitive response when the target prostate-specific antigen in buffer solution was added to the antibody-immobilized sensing area. The current change showed a logarithm relationship against the PSA concentration from 0.1 pg/ml to 0.993 ng/ml. The sensitivity of 0.215% is determined for 0.1 pg/ml PSA solution. The above experimental result of the biomolecule-gated AlGaN/GaN HEMT biosensor suggested that this biosensor might be a useful tool for prostate cancer screening.

[What is hidden behind the Baking Tray Task? Study of sensibility and specificity in right-hemispheric stroke patients].

PubMed

Garcia-Fernandez, Juan; Garcia-Molina, Alberto; Aparicio-Lopez, Celeste; Sanchez-Carrion, Rocío; Ensenat, Antònia; Pena-Casanova, Jordi; Roig-Rovira, Teresa

2015-12-16

Tham and Tegner proposed the Baking Tray Task (BTT) as a fast simple assessment test for detecting spatial negligence. However, very few studies have examined its validity as a diagnostic test. To analyse the diagnostic validity of the BTT by measuring its specificity and sensitivity in a sample of subjects with right hemisphere strokes. Forty-eight patients with right hemisphere vascular lesions were distributed in two groups (negligence group, n = 35; non-negligence group, n = 13) according to the scores obtained in a battery of visuospatial examination tests. The participants' performance on the BTT was compared with that of a healthy control group (n = 12). The results showed a high level of sensitivity of the BTT, but low specificity. The performance on the BTT of eight of the 13 members of the non-negligence group was suggestive of negligence. The BTT has proved to be a sensitive test for the detection of spatial negligence. Yet, based on its low specificity, its use alone as a single diagnostic test is not recommended.

Differentiating the origin of outflow tract ventricular arrhythmia using a simple, novel approach.

PubMed

Efimova, Elena; Dinov, Borislav; Acou, Willem-Jan; Schirripa, Valentina; Kornej, Jelena; Kosiuk, Jedrzej; Rolf, Sascha; Sommer, Philipp; Richter, Sergio; Bollmann, Andreas; Hindricks, Gerhard; Arya, Arash

2015-07-01

Numerous electrocardiographic (ECG) criteria have been proposed to identify localization of outflow tract ventricular arrhythmias (OT-VAs); however, in some cases, it is difficult to accurately localize the origin of OT-VA using the surface ECG. The purpose of this study was to assess a simple criterion for localization of OT-VAs during electrophysiology study. We measured the interval from the onset of the earliest QRS complex of premature ventricular contractions (PVCs) to the distal right ventricular apical signal (the QRS-RVA interval) in 66 patients (31 men aged 53.3 ± 14.0 years; right ventricular outflow tract [RVOT] origin in 37) referred for ablation of symptomatic outflow tract PVCs. We prospectively validated this criterion in 39 patients (22 men aged 52 ± 15 years; RVOT origin in 19). Compared with patients with RVOT PVCs, the QRS-RVA interval was significantly longer in patients with left ventricular outflow tract (LVOT) PVCs (70 ± 14 vs 33.4±10 ms, P < .001). Receiver operating characteristic analysis showed that a QRS-RVA interval ≥49 ms had sensitivity, specificity, and positive and negative predictive values of 100%, 94.6%, 93.5%, and 100%, respectively, for prediction of an LVOT origin. The same analysis in the validation cohort showed sensitivity, specificity, and positive and negative predictive values of 94.7%, 95%, 95%, and 94.7%, respectively. When these data were combined, a QRS-RVA interval ≥49 ms had sensitivity, specificity, and positive and negative predictive values of 98%, 94.6%, 94.1%, and 98.1%, respectively, for prediction of an LVOT origin. A QRS-RVA interval ≥49 ms suggests an LVOT origin. The QRS-RVA interval is a simple and accurate criterion for differentiating the origin of outflow tract arrhythmia during electrophysiology study; however, the accuracy of this criterion in identifying OT-VA from the right coronary cusp is limited. Copyright © 2015 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.

Comparative analysis of multiple-casualty incident triage algorithms.

PubMed

Garner, A; Lee, A; Harrison, K; Schultz, C H

2001-11-01

We sought to retrospectively measure the accuracy of multiple-casualty incident (MCI) triage algorithms and their component physiologic variables in predicting adult patients with critical injury. We performed a retrospective review of 1,144 consecutive adult patients transported by ambulance and admitted to 2 trauma centers. Association between first-recorded out-of-hospital physiologic variables and a resource-based definition of severe injury appropriate to the MCI context was determined. The association between severe injury and Triage Sieve, Simple Triage and Rapid Treatment, modified Simple Triage and Rapid Treatment, and CareFlight Triage was determined in the patient population. Of the physiologic variables, the Motor Component of the Glasgow Coma Scale had the strongest association with severe injury, followed by systolic blood pressure. The differences between CareFlight Triage, Simple Triage and Rapid Treatment, and modified Simple Triage and Rapid Treatment were not dramatic, with sensitivities of 82% (95% confidence interval [CI] 75% to 88%), 85% (95% CI 78% to 90%), and 84% (95% CI 76% to 89%), respectively, and specificities of 96% (95% CI 94% to 97%), 86% (95% CI 84% to 88%), and 91% (95% CI 89% to 93%), respectively. Both forms of Triage Sieve were significantly poorer predictors of severe injury. Of the physiologic variables used in the triage algorithms, the Motor Component of the Glasgow Coma Scale and systolic blood pressure had the strongest association with severe injury. CareFlight Triage, Simple Triage and Rapid Treatment, and modified Simple Triage and Rapid Treatment had similar sensitivities in predicting critical injury in designated trauma patients, but CareFlight Triage had better specificity. Because patients in a true mass casualty situation may not be completely comparable with designated trauma patients transported to emergency departments in routine circumstances, the best triage instrument in this study may not be the best in an actual MCI. These findings must be validated prospectively before their accuracy can be confirmed.

Simple immunoglobulin G sensor based on thin core single-mode fiber

NASA Astrophysics Data System (ADS)

Zheng, Yingfang; Lang, Tingting; Shen, Tingting; Shen, Changyu

2018-03-01

In this paper, a simple fiber biosensor (FOB) for immunoglobulin G (IgG) detection is designed and experimentally verified. The FOB is constructed by a 20 mm long thin core single-mode fiber (TCSMF) sandwiched between two single-mode optical fibers (SMFs). First, the refractive index (RI) sensitivity of the fiber structures is calculated by the beam propagation method. The refractive index sensing experiment is performed using different concentrations of glycerol solutions, and the experimental results are mostly consistent with the simulation predictions. The experimental RI sensitivity increases with the surrounding RI and reaches 82.7 nm/RIU. Then the surface of the FOB is functionalized by APTES for covalent bonding. The human IgG and goat anti-human IgG are chosen as a bioconjugated pair to examine the bio-sensing effectiveness of this FOB. The sensitivity of IgG detection is determined to be 10.4 nm/(mg/ml). And the serum IgG concentration in normal adults lies within the range of 6-16 mg/ml (Worsfold et al., 1985), so the sensor is applicable to human IgG monitoring. The specificity of the FOB is also verified by a contrast experiment conducted using rabbit immunoglobulin G. The proposed FOB is simple, low loss, cost-effective, and can be used for various biological and chemical applications.

IOTA simple rules in differentiating between benign and malignant ovarian tumors.

PubMed

Tantipalakorn, Charuwan; Wanapirak, Chanane; Khunamornpong, Surapan; Sukpan, Kornkanok; Tongsong, Theera

2014-01-01

To evaluate the diagnostic performance of IOTA simple rules in differentiating between benign and malignant ovarian tumors. A study of diagnostic performance was conducted on women scheduled for elective surgery due to ovarian masses between March 2007 and March 2012. All patients underwent ultrasound examination for IOTA simple rules within 24 hours of surgery. All examinations were performed by the authors, who had no any clinical information of the patients, to differentiate between benign and malignant adnexal masses using IOTA simple rules. Gold standard diagnosis was based on pathological or operative findings. A total of 398 adnexal masses, in 376 women, were available for analysis. Of them, the IOTA simple rules could be applied in 319 (80.1%) including 212 (66.5%) benign tumors and 107 (33.6%) malignant tumors. The simple rules yielded inconclusive results in 79 (19.9%) masses. In the 319 masses for which the IOTA simple rules could be applied, sensitivity was 82.9% and specificity 95.3%. The IOTA simple rules have high diagnostic performance in differentiating between benign and malignant adnexal masses. Nevertheless, inconclusive results are relatively common.

Diagnostic value of ultrasound indicators of neoplastic risk in preoperative differentiation of adnexal masses

PubMed Central

Bachanek, Michał; Trojanowski, Seweryn; Cendrowski, Krzysztof; Sawicki, Włodzimierz

2013-01-01

Aim To assess the diagnostic value of the risk of malignancy indices and simple ultrasound- based rules in preoperative differentiation of adnexal masses. Material and methods Retrospective examination of 87 patients admitted to hospital due to adnexal tumors. The lesions were evaluated on the basis of international ultrasound classification of ovarian tumors and four risk of malignancy indices were calculated based on ultrasound examination, concentration of CA 125 and menopausal status. Results The patients were aged between 17 and 79, the mean age was 44.5 (standard deviation SD=16.6). Most of the patients (60.91%) were before their menopause. The sensitivity of the simple ultrasound-based rules in the diagnosis of malignancies equaled 64.71% and the specificity constituted 90.00%. A significant statistical difference in the presence of the malignant process was demonstrated in relation to age, menopausal status, CA 125 concentration and analyzed ultrasound score. All indices were characterized by similar sensitivity and specificity. The highest specificity and predictive value of malignant lesions out of the assessed ones was demonstrated by the risk of malignancy index proposed by Yamamoto. The risk of malignancy index according to Jacobs, however, showed the highest predictive value in the case of non-malignant lesions. Conclusions The multiparametric ultrasound examination may facilitate the selection of patients with adnexal tumors to provide them with an appropriate treatment – observation, laparotomy and laparoscopy. These parameters constitute a simple ambulatory method of determining the character of adnexal masses before recommending appropriate treatment. PMID:26674849

Prospective Cohort Study Evaluating the Prognostic Value of Simple EEG Parameters in Postanoxic Coma.

PubMed

Azabou, Eric; Fischer, Catherine; Mauguiere, François; Vaugier, Isabelle; Annane, Djillali; Sharshar, Tarek; Lofaso, Fréderic

2016-01-01

We prospectively studied early bedside standard EEG characteristics in 61 acute postanoxic coma patients. Five simple EEG features, namely, isoelectric, discontinuous, nonreactive to intense auditory and nociceptive stimuli, dominant delta frequency, and occurrence of paroxysms were classified yes or no. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and area under the receiver operating characteristic curve (AUC) of each of these variables for predicting an unfavorable outcome, defined as death, persistent vegetative state, minimally conscious state, or severe neurological disability, as assessed 1 year after coma onset were computed as well as Synek's score. The outcome was unfavorable in 56 (91.8%) patients. Sensitivity, specificity, PPV, NPV, and AUC of nonreactive EEG for predicting an unfavorable outcome were 84%, 80%, 98%, 31%, and 0.82, respectively; and were all very close to the ones of Synek score>3, which were 82%, 80%, 98%, 29%, and 0.81, respectively. Specificities for predicting an unfavorable outcome were 100% for isoelectric, discontinuous, or dominant delta activity EEG. These 3 last features were constantly associated to unfavorable outcome. Absent EEG reactivity strongly predicted an unfavorable outcome in postanoxic coma, and performed as accurate as a Synek score>3. Analyzing characteristics of some simple EEG features may easily help nonneurophysiologist physicians to investigate prognostic issue of postanoxic coma patient. In this study (a) discontinuous, isoelectric, or delta-dominant EEG were constantly associated with unfavorable outcome and (b) nonreactive EEG performed prognostic as accurate as a Synek score>3. © EEG and Clinical Neuroscience Society (ECNS) 2015.

Loop-Mediated Isothermal Amplification Label-Based Gold Nanoparticles Lateral Flow Biosensor for Detection of Enterococcus faecalis and Staphylococcus aureus

PubMed Central

Wang, Yi; Li, Hui; Wang, Yan; Zhang, Lu; Xu, Jianguo; Ye, Changyun

2017-01-01

The report describes a simple, rapid and sensitive assay for visual and multiplex detection of Enterococcus faecalis and Staphylococcus aureus based on multiple loop-mediated isothermal amplification (mLAMP) and lateral flow biosensor (LFB). Detection and differentiation of the Ef0027 gene (E. faecalis-specific gene) and nuc gene (S. aureus-specific gene) were determined using fluorescein (FITC)-and digoxin-modified primers in the mLAMP process. In the presence of biotin- and FITC-/digoxin-modified primers, the mLAMP yielded numerous biotin- and FITC-/digoxin-attached duplex products, which were detected by LFB through biotin/streptavidin interaction (biotin on the duplex and streptavidin on the gold nanoparticle) and immunoreactions (FITC/digoxin on the duplex and anti-FITC/digoxin on the LFB test line). The accumulation of gold nanoparticles generated a characteristic red line, enabling visual and multiplex detection of target pathogens without instrumentation. The limit of detection (LoD), analytical specificity and feasibility of LAMP-LFB technique were successfully examined in pure culture and blood samples. The entire procedure, including specimen (blood samples) processing (30 min), isothermal reaction (40 min) and result reporting (within 2 min), could be completed within 75 min. Thus, this assay offers a simple, rapid, sensitive and specific test for multiplex detection of E. faecalis and S. aureus strains. Furthermore, the LAMP-LFB strategy is a universal technique, which can be extended to detect various target sequences by re-designing the specific LAMP primers. PMID:28239371

Direct ultrasensitive electrochemical biosensing of pathogenic DNA using homogeneous target-initiated transcription amplification

PubMed Central

Yan, Yurong; Ding, Shijia; Zhao, Dan; Yuan, Rui; Zhang, Yuhong; Cheng, Wei

2016-01-01

Sensitive and specific methodologies for detection of pathogenic gene at the point-of-care are still urgent demands in rapid diagnosis of infectious diseases. This work develops a simple and pragmatic electrochemical biosensing strategy for ultrasensitive and specific detection of pathogenic nucleic acids directly by integrating homogeneous target-initiated transcription amplification (HTITA) with interfacial sensing process in single analysis system. The homogeneous recognition and specific binding of target DNA with the designed hairpin probe triggered circular primer extension reaction to form DNA double-strands which contained T7 RNA polymerase promoter and served as templates for in vitro transcription amplification. The HTITA protocol resulted in numerous single-stranded RNA products which could synchronously hybridized with the detection probes and immobilized capture probes for enzyme-amplified electrochemical detection on the biosensor surface. The proposed electrochemical biosensing strategy showed very high sensitivity and selectivity for target DNA with a dynamic response range from 1 fM to 100 pM. Using salmonella as a model, the established strategy was successfully applied to directly detect invA gene from genomic DNA extract. This proposed strategy presented a simple, pragmatic platform toward ultrasensitive nucleic acids detection and would become a versatile and powerful tool for point-of-care pathogen identification. PMID:26729209

Direct ultrasensitive electrochemical biosensing of pathogenic DNA using homogeneous target-initiated transcription amplification

NASA Astrophysics Data System (ADS)

Yan, Yurong; Ding, Shijia; Zhao, Dan; Yuan, Rui; Zhang, Yuhong; Cheng, Wei

2016-01-01

Sensitive and specific methodologies for detection of pathogenic gene at the point-of-care are still urgent demands in rapid diagnosis of infectious diseases. This work develops a simple and pragmatic electrochemical biosensing strategy for ultrasensitive and specific detection of pathogenic nucleic acids directly by integrating homogeneous target-initiated transcription amplification (HTITA) with interfacial sensing process in single analysis system. The homogeneous recognition and specific binding of target DNA with the designed hairpin probe triggered circular primer extension reaction to form DNA double-strands which contained T7 RNA polymerase promoter and served as templates for in vitro transcription amplification. The HTITA protocol resulted in numerous single-stranded RNA products which could synchronously hybridized with the detection probes and immobilized capture probes for enzyme-amplified electrochemical detection on the biosensor surface. The proposed electrochemical biosensing strategy showed very high sensitivity and selectivity for target DNA with a dynamic response range from 1 fM to 100 pM. Using salmonella as a model, the established strategy was successfully applied to directly detect invA gene from genomic DNA extract. This proposed strategy presented a simple, pragmatic platform toward ultrasensitive nucleic acids detection and would become a versatile and powerful tool for point-of-care pathogen identification.

Direct ultrasensitive electrochemical biosensing of pathogenic DNA using homogeneous target-initiated transcription amplification.

PubMed

Yan, Yurong; Ding, Shijia; Zhao, Dan; Yuan, Rui; Zhang, Yuhong; Cheng, Wei

2016-01-05

Sensitive and specific methodologies for detection of pathogenic gene at the point-of-care are still urgent demands in rapid diagnosis of infectious diseases. This work develops a simple and pragmatic electrochemical biosensing strategy for ultrasensitive and specific detection of pathogenic nucleic acids directly by integrating homogeneous target-initiated transcription amplification (HTITA) with interfacial sensing process in single analysis system. The homogeneous recognition and specific binding of target DNA with the designed hairpin probe triggered circular primer extension reaction to form DNA double-strands which contained T7 RNA polymerase promoter and served as templates for in vitro transcription amplification. The HTITA protocol resulted in numerous single-stranded RNA products which could synchronously hybridized with the detection probes and immobilized capture probes for enzyme-amplified electrochemical detection on the biosensor surface. The proposed electrochemical biosensing strategy showed very high sensitivity and selectivity for target DNA with a dynamic response range from 1 fM to 100 pM. Using salmonella as a model, the established strategy was successfully applied to directly detect invA gene from genomic DNA extract. This proposed strategy presented a simple, pragmatic platform toward ultrasensitive nucleic acids detection and would become a versatile and powerful tool for point-of-care pathogen identification.

Validation of the "early detection Primary Care Checklist" in an Italian community help-seeking sample: The "checklist per la Valutazione dell'Esordio Psicotico".

PubMed

Pelizza, Lorenzo; Raballo, Andrea; Semrov, Enrico; Chiri, Luigi Rocco; Azzali, Silvia; Scazza, Ilaria; Garlassi, Sara; Paterlini, Federica; Fontana, Francesca; Favazzo, Rosanna; Pensieri, Luana; Fabiani, Michela; Cioncolini, Leonardo; Pupo, Simona

2017-07-26

To establish the concordant validity of the "Checklist per la Valutazione dell'Esordio Psicotico" (CVEP) in an Italian help-seeking population. The CVEP is the Italian adaptation of the "early detection Primary Care Checklist," a 20-item tool specifically designed to assist primary care practitioners in identifying young people in the early stages of psychosis. The checklist was completed by the referring practitioners of 168 young people referred to the "Reggio Emilia At Risk Mental States" Project, an early detection infrastructure developed under the aegis of the Regional Project on Early Detection of Psychosis in the Reggio Emilia Department of Mental Health. The concordant validity of the CVEP was established by comparing screen results with the outcome of the "Comprehensive Assessment of At Risk Mental States" (CAARMS), a gold standard assessment for identifying young people who may be at risk of developing psychosis. The simple checklist as originally conceived had excellent sensitivity (98%), but lower specificity (58%). Using only a CVEP total score of 20 or above as cut-off, the tool showed a slightly lower sensitivity (93%) with a substantial improvement in specificity (87%). Simple cross-tabulations of the individual CVEP item scores against CAARMS outcome to identify the more discriminant item in terms of sensitivity and specificity were carried out. In comparison to other, much longer, screening tools, the CVEP performed well to identify young people in the early stages of psychosis. Therefore, the CVEP is well suited to optimize appropriate referrals to specialist services, building on the skills and knowledge already available in primary care settings. © 2017 John Wiley & Sons Australia, Ltd.

The development of a loop-mediated isothermal amplification assay for rapid and sensitive detection of abalone herpesvirus DNA.

PubMed

Chen, M H; Kuo, S T; Renault, T; Chang, P H

2014-02-01

A loop-mediated isothermal amplification (LAMP) assay was developed for the detection of abalone herpesvirus DNA. Two pairs of primers were designed, based on the sequence of the DNA polymerase gene of abalone herpesvirus. The reaction temperature and time were optimized to 63°C and 60min, respectively. LAMP amplicons were analyzed by 2% agarose gel electrophoresis or by visual inspection of a colour change emitted by fluorescent dye. The method developed was specific for the detection of abalone herpesvirus, without cross-reactions with other tested herpesviruses including ostreid herpesvirus 1 (OsHV-1), European eel herpesvirus, koi herpesvirus (KHV) and an avian herpesvirus. The LAMP assay was 100 folds more sensitive than a conventional PCR and 10 folds less sensitive than a SYBR Green PCR. These results indicate that the developed LAMP assay is a simple, rapid, sensitive, specific and reliable technique for the detection of abalone herpesvirus. Copyright © 2013 Elsevier B.V. All rights reserved.

A simple and rapid DNA extraction method from whole blood for highly sensitive detection and quantitation of HIV-1 proviral DNA by real-time PCR.

PubMed

McFall, Sally M; Wagner, Robin L; Jangam, Sujit R; Yamada, Douglas H; Hardie, Diana; Kelso, David M

2015-03-01

Early diagnosis and access to treatment for infants with human immunodeficiency virus-1 (HIV-1) is critical to reduce infant mortality. The lack of simple point-of-care tests impedes the timely initiation of antiretroviral therapy. The development of FINA, filtration isolation of nucleic acids, a novel DNA extraction method that can be performed by clinic personnel in less than 2 min has been reported previously. In this report, significant improvements in the DNA extraction and amplification methods are detailed that allow sensitive quantitation of as little as 10 copies of HIV-1 proviral DNA and detection of 3 copies extracted from 100 μl of whole blood. An internal control to detect PCR inhibition was also incorporated. In a preliminary field evaluation of 61 South African infants, the FINA test demonstrated 100% sensitivity and specificity. The proviral copy number of the infant specimens was quantified, and it was established that 100 microliters of whole blood is required for sensitive diagnosis of infants. Copyright © 2015 The Authors. Published by Elsevier B.V. All rights reserved.

The cut-off values of anthropometric variables for predicting mild cognitive impairment in Malaysian older adults: a large population based cross-sectional study.

PubMed

Won, Huiloo; Abdul, Manaf Zahara; Mat Ludin, Arimi Fitri; Omar, Mohd Azahadi; Razali, Rosdinom; Shahar, Suzana

2017-01-01

Older adults are at risk of mild cognitive impairment (MCI), and simple anthropometric measurements can be used to screen for this condition. Thus, the aim of this study was to explore the cut-off values of body mass index (BMI) and waist circumference (WC) for predicting the risk of MCI in older Malaysian adults. A total of 2,240 Malaysian older adults aged ≥60 years were recruited using multistage random sampling in a population based cross-sectional study. Receiver operating characteristic (ROC) curve was used to determine the cut-off values of BMI and WC with optimum sensitivity and specificity for the detection of MCI. Age, gender, years of education, smoking habit, alcohol consumption, depression, and medical conditions were used as confounding factors in this analysis. A BMI cut-off value of 26 kg/m 2 (area under the receiver operating characteristic curve [AUC] 0.725; sensitivity 90.5%; specificity 38.8%) was appropriate in identifying the risk of getting MCI in both men and women. The optimum WC cut-offs for likelihood of MCI were 90 cm (AUC 0.745; sensitivity 78.0%; specificity 59.8%) for men and 82 cm (AUC 0.714; sensitivity 84.3%; specificity 49.7%) for women. The optimum calf circumference (CC) cut-off values for identifying MCI were 29 cm (AUC 0.731; sensitivity 72.6%; specificity 61.1%) for men and 26 cm (AUC 0.598; sensitivity 79.1%; specificity 45.3%) for women. The cut-off values could be advocated and used as part of the screening of MCI among older Malaysian adults. There is a need to further determine the predictive values of these cut-off points on outcomes through longitudinal study design.

Predicting the risk of malignancy in adnexal masses based on the Simple Rules from the International Ovarian Tumor Analysis group.

PubMed

Timmerman, Dirk; Van Calster, Ben; Testa, Antonia; Savelli, Luca; Fischerova, Daniela; Froyman, Wouter; Wynants, Laure; Van Holsbeke, Caroline; Epstein, Elisabeth; Franchi, Dorella; Kaijser, Jeroen; Czekierdowski, Artur; Guerriero, Stefano; Fruscio, Robert; Leone, Francesco P G; Rossi, Alberto; Landolfo, Chiara; Vergote, Ignace; Bourne, Tom; Valentin, Lil

2016-04-01

Accurate methods to preoperatively characterize adnexal tumors are pivotal for optimal patient management. A recent metaanalysis concluded that the International Ovarian Tumor Analysis algorithms such as the Simple Rules are the best approaches to preoperatively classify adnexal masses as benign or malignant. We sought to develop and validate a model to predict the risk of malignancy in adnexal masses using the ultrasound features in the Simple Rules. This was an international cross-sectional cohort study involving 22 oncology centers, referral centers for ultrasonography, and general hospitals. We included consecutive patients with an adnexal tumor who underwent a standardized transvaginal ultrasound examination and were selected for surgery. Data on 5020 patients were recorded in 3 phases from 2002 through 2012. The 5 Simple Rules features indicative of a benign tumor (B-features) and the 5 features indicative of malignancy (M-features) are based on the presence of ascites, tumor morphology, and degree of vascularity at ultrasonography. Gold standard was the histopathologic diagnosis of the adnexal mass (pathologist blinded to ultrasound findings). Logistic regression analysis was used to estimate the risk of malignancy based on the 10 ultrasound features and type of center. The diagnostic performance was evaluated by area under the receiver operating characteristic curve, sensitivity, specificity, positive likelihood ratio (LR+), negative likelihood ratio (LR-), positive predictive value (PPV), negative predictive value (NPV), and calibration curves. Data on 4848 patients were analyzed. The malignancy rate was 43% (1402/3263) in oncology centers and 17% (263/1585) in other centers. The area under the receiver operating characteristic curve on validation data was very similar in oncology centers (0.917; 95% confidence interval, 0.901-0.931) and other centers (0.916; 95% confidence interval, 0.873-0.945). Risk estimates showed good calibration. In all, 23% of patients in the validation data set had a very low estimated risk (<1%) and 48% had a high estimated risk (≥30%). For the 1% risk cutoff, sensitivity was 99.7%, specificity 33.7%, LR+ 1.5, LR- 0.010, PPV 44.8%, and NPV 98.9%. For the 30% risk cutoff, sensitivity was 89.0%, specificity 84.7%, LR+ 5.8, LR- 0.13, PPV 75.4%, and NPV 93.9%. Quantification of the risk of malignancy based on the Simple Rules has good diagnostic performance both in oncology centers and other centers. A simple classification based on these risk estimates may form the basis of a clinical management system. Patients with a high risk may benefit from surgery by a gynecological oncologist, while patients with a lower risk may be managed locally. Copyright © 2016 Elsevier Inc. All rights reserved.

Direct detection of hyaluronidase in urine using cationic gold nanoparticles: a potential diagnostic test for bladder cancer.

PubMed

Nossier, Ahmed Ibrahim; Eissa, Sanaa; Ismail, Manal Fouad; Hamdy, Mohamed Ahmed; Azzazy, Hassan Mohamed El-Said

2014-04-15

Hyaluronidase (HAase) was reported as a urinary marker of bladder cancer. In this study, a simple colorimetric gold nanoparticle (AuNP) assay was developed for rapid and sensitive detection of urinary HAase activity. Charge interaction between polyanionic hyaluronic acid (HA) and cationic AuNPs stabilized with cetyl trimethyl ammonium bromide (CTAB) led to formation of gold aggregates and a red to blue color shift. HAase digests HA into small fragments preventing the aggregation of cationic AuNPs. The nonspecific aggregation of AuNPs in urine samples was overcome by pre-treatment of samples with the polycationic chitosan that was able to agglomerate all negatively charged interfering moieties before performing the assay. The developed AuNP assay was compared with zymography for qualitative detection of urinary HAase activity in 40 bladder carcinoma patients, 11 benign bladder lesions patients and 15 normal individuals, the assay sensitivity was 82.5% vs. 65% for zymography, while the specificity for both assays was 96.1%. The absorption ratio, A530/A620 of the reacted AuNP solution was used to quantify the HAase activity. The best cut off value was 93.5 μU/ng protein, at which the sensitivity was 90% and the specificity was 80.8%.The developed colorimetric AuNP HAase assay is simple, inexpensive, and can aid noninvasive diagnosis of bladder cancer. © 2013 Elsevier B.V. All rights reserved.

'Nano-immuno test' for the detection of live Mycobacterium avium subspecies paratuberculosis bacilli in the milk samples using magnetic nano-particles and chromogen.

PubMed

Singh, Manju; Singh, Shoor Vir; Gupta, Saurabh; Chaubey, Kundan Kumar; Stephan, Bjorn John; Sohal, Jagdip Singh; Dutta, Manali

2018-04-26

Early rapid detection of Mycobacterium avium subspecies paratuberculosis (MAP) bacilli in milk samples is the major challenge since traditional culture method is time consuming and laboratory dependent. We report a simple, sensitive and specific nano-technology based 'Nano-immuno test' capable of detecting viable MAP bacilli in the milk samples within 10 h. Viable MAP bacilli were captured by MAP specific antibody-conjugated magnetic nano-particles using resazurin dye as chromogen. Test was optimized using true culture positive (10-bovine and 12-goats) and true culture negative (16-bovine and 25-goats) raw milk samples. Domestic livestock species in India are endemically infected with MAP. After successful optimization, sensitivity and specificity of the 'nano-immuno test' in goats with respect to milk culture was 91.7% and 96.0%, respectively. Whereas, it was 90.0% (sensitivity) and 92.6% (specificity) with respect to IS900 PCR. In bovine milk samples, sensitivity and specificity of 'nano-immuno test' with respect to milk culture was 90.0% and 93.7%, respectively. However, with respect to IS900 PCR, the sensitivity and specificity was 88.9% and 94.1%, respectively. Test was validated with field raw milk samples (goats-258 and bovine-138) collected from domestic livestock species to detect live/viable MAP bacilli. Of 138 bovine raw milk samples screened by six diagnostic tests, 81 (58.7%) milk samples were positive for MAP infection in one or more than one diagnostic tests. Of 81 (58.7%) positive bovine raw milk samples, only 24 (17.4%) samples were detected positive for the presence of viable MAP bacilli. Of 258 goats raw milk samples screened by six diagnostic tests, 141 (54.6%) were positive for MAP infection in one or more than one test. Of 141 (54.6%) positive raw milk samples from goats, only 48 (34.0%) were detected positive for live MAP bacilli. Simplicity and efficiency of this novel 'nano-immuno test' makes it suitable for wide-scale screening of milk samples in the field. Standardization, validation and re-usability of functionalized nano-particles and the test was successfully achieved in field samples. Test was highly specific, simple to perform and easy to read by naked eyes and does not require laboratory support in the performance of test. Test has potential to be used as screening test to estimate bio-load of MAP in milk samples at National level.

Spectrophotometric total reducing sugars assay based on cupric reduction.

PubMed

Başkan, Kevser Sözgen; Tütem, Esma; Akyüz, Esin; Özen, Seda; Apak, Reşat

2016-01-15

As the concentration of reducing sugars (RS) is controlled by European legislation for certain specific food and beverages, a simple and sensitive spectrophotometric method for the determination of RS in various food products is proposed. The method is based on the reduction of Cu(II) to Cu(I) with reducing sugars in alkaline medium in the presence of 2,9-dimethyl-1,10-phenanthroline (neocuproine: Nc), followed by the formation of a colored Cu(I)-Nc charge-transfer complex. All simple sugars tested had the linear regression equations with almost equal slope values. The proposed method was successfully applied to fresh apple juice, commercial fruit juices, milk, honey and onion juice. Interference effect of phenolic compounds in plant samples was eliminated by a solid phase extraction (SPE) clean-up process. The method was proven to have higher sensitivity and precision than the widely used dinitrosalicylic acid (DNS) colorimetric method. Copyright © 2015 Elsevier B.V. All rights reserved.

A simple model of space radiation damage in GaAs solar cells

NASA Technical Reports Server (NTRS)

Wilson, J. W.; Stith, J. J.; Stock, L. V.

1983-01-01

A simple model is derived for the radiation damage of shallow junction gallium arsenide (GaAs) solar cells. Reasonable agreement is found between the model and specific experimental studies of radiation effects with electron and proton beams. In particular, the extreme sensitivity of the cell to protons stopping near the cell junction is predicted by the model. The equivalent fluence concept is of questionable validity for monoenergetic proton beams. Angular factors are quite important in establishing the cell sensitivity to incident particle types and energies. A fluence of isotropic incidence 1 MeV electrons (assuming infinite backing) is equivalent to four times the fluence of normal incidence 1 MeV electrons. Spectral factors common to the space radiations are considered, and cover glass thickness required to minimize the initial damage for a typical cell configuration is calculated. Rough equivalence between the geosynchronous environment and an equivalent 1 MeV electron fluence (normal incidence) is established.

Simultaneous ultramicroanalysis of both 17-keto-and 17beta-hydroxy androgens in biological fluids.

PubMed

Ganjam, V K

1976-11-01

Sensitive methods for quantifying androgens were lacking. Therefore, a relatively simple procedure for separating steroids was combined with highly specific assay methods so that eight androgens could be measured with high accuracy, precision and sensitivity. Semi-automated separations on Sephadex LH-20 columns used heptane:methylene chloride:ethanol:water (50:50:1:0.12) and a flow rate of 17.0 min/ml. The six peaks eluted contained androstenedine; androsterone, epiandrosterone and dihydrotestosterone; testosterone and dehydroepiandrosterone; 3alpha-androstanediol; 3beta-androstanediol; and androstenediol. Androstenedione, dehydroepiandrosterone and androstenediol were quantified using specific antisera (sensitivity less than or equal to 75 pg). Testosterone and dihydrotestosterone were measured by competitive protein-binding assays using rabbit TeBG (sensitivity less than or equal to 150 pg). 3alpha- and 3beta-androstanediol were similarly assayed using human TeBG (sensitivity approximately 150 pg). Androsterone was reduced with NaBH4 and the resulting 3alpha-androstanediol was assayed using human TeBG (sensitivity approximately 200 pg). Inter- and intra-assay variations were less than 10% for radioimmunoassays and less than 16% for competitive protein-binding assays over the entire dose response curve.

Simple, Sensitive and Accurate Multiplex Detection of Clinically Important Melanoma DNA Mutations in Circulating Tumour DNA with SERS Nanotags

PubMed Central

Wee, Eugene J.H.; Wang, Yuling; Tsao, Simon Chang-Hao; Trau, Matt

2016-01-01

Sensitive and accurate identification of specific DNA mutations can influence clinical decisions. However accurate diagnosis from limiting samples such as circulating tumour DNA (ctDNA) is challenging. Current approaches based on fluorescence such as quantitative PCR (qPCR) and more recently, droplet digital PCR (ddPCR) have limitations in multiplex detection, sensitivity and the need for expensive specialized equipment. Herein we describe an assay capitalizing on the multiplexing and sensitivity benefits of surface-enhanced Raman spectroscopy (SERS) with the simplicity of standard PCR to address the limitations of current approaches. This proof-of-concept method could reproducibly detect as few as 0.1% (10 copies, CV < 9%) of target sequences thus demonstrating the high sensitivity of the method. The method was then applied to specifically detect three important melanoma mutations in multiplex. Finally, the PCR/SERS assay was used to genotype cell lines and ctDNA from serum samples where results subsequently validated with ddPCR. With ddPCR-like sensitivity and accuracy yet at the convenience of standard PCR, we believe this multiplex PCR/SERS method could find wide applications in both diagnostics and research. PMID:27446486

Simple, Sensitive and Accurate Multiplex Detection of Clinically Important Melanoma DNA Mutations in Circulating Tumour DNA with SERS Nanotags.

PubMed

Wee, Eugene J H; Wang, Yuling; Tsao, Simon Chang-Hao; Trau, Matt

2016-01-01

Sensitive and accurate identification of specific DNA mutations can influence clinical decisions. However accurate diagnosis from limiting samples such as circulating tumour DNA (ctDNA) is challenging. Current approaches based on fluorescence such as quantitative PCR (qPCR) and more recently, droplet digital PCR (ddPCR) have limitations in multiplex detection, sensitivity and the need for expensive specialized equipment. Herein we describe an assay capitalizing on the multiplexing and sensitivity benefits of surface-enhanced Raman spectroscopy (SERS) with the simplicity of standard PCR to address the limitations of current approaches. This proof-of-concept method could reproducibly detect as few as 0.1% (10 copies, CV < 9%) of target sequences thus demonstrating the high sensitivity of the method. The method was then applied to specifically detect three important melanoma mutations in multiplex. Finally, the PCR/SERS assay was used to genotype cell lines and ctDNA from serum samples where results subsequently validated with ddPCR. With ddPCR-like sensitivity and accuracy yet at the convenience of standard PCR, we believe this multiplex PCR/SERS method could find wide applications in both diagnostics and research.

Validation of simple indexes to assess insulin sensitivity during pregnancy in Wistar and Sprague-Dawley rats.

PubMed

Cacho, J; Sevillano, J; de Castro, J; Herrera, E; Ramos, M P

2008-11-01

Insulin resistance plays a role in the pathogenesis of diabetes, including gestational diabetes. The glucose clamp is considered the gold standard for determining in vivo insulin sensitivity, both in human and in animal models. However, the clamp is laborious, time consuming and, in animals, requires anesthesia and collection of multiple blood samples. In human studies, a number of simple indexes, derived from fasting glucose and insulin levels, have been obtained and validated against the glucose clamp. However, these indexes have not been validated in rats and their accuracy in predicting altered insulin sensitivity remains to be established. In the present study, we have evaluated whether indirect estimates based on fasting glucose and insulin levels are valid predictors of insulin sensitivity in nonpregnant and 20-day-pregnant Wistar and Sprague-Dawley rats. We have analyzed the homeostasis model assessment of insulin resistance (HOMA-IR), the quantitative insulin sensitivity check index (QUICKI), and the fasting glucose-to-insulin ratio (FGIR) by comparing them with the insulin sensitivity (SI(Clamp)) values obtained during the hyperinsulinemic-isoglycemic clamp. We have performed a calibration analysis to evaluate the ability of these indexes to accurately predict insulin sensitivity as determined by the reference glucose clamp. Finally, to assess the reliability of these indexes for the identification of animals with impaired insulin sensitivity, performance of the indexes was analyzed by receiver operating characteristic (ROC) curves in Wistar and Sprague-Dawley rats. We found that HOMA-IR, QUICKI, and FGIR correlated significantly with SI(Clamp), exhibited good sensitivity and specificity, accurately predicted SI(Clamp), and yielded lower insulin sensitivity in pregnant than in nonpregnant rats. Together, our data demonstrate that these indexes provide an easy and accurate measure of insulin sensitivity during pregnancy in the rat.

A novel strategy for rapid detection of NT-proBNP

NASA Astrophysics Data System (ADS)

Cui, Qiyao; Sun, Honghao; Zhu, Hui

2017-09-01

In order to establish a simple, rapid, sensitive, and specific quantitative assay to detect the biomarkers of heart failure, in this study, biotin-streptavidin technology was employed with fluorescence immunochromatographic assay to detect the concentration of the biomarkers in serum, and this method was applied to detect NT-proBNP, which is valuable for diagnostic evaluation of heart failure.

Electrophoresis Gel Quantification with a Flatbed Scanner and Versatile Lighting from a Screen Scavenged from a Liquid Crystal Display (LCD) Monitor

ERIC Educational Resources Information Center

Yeung, Brendan; Ng, Tuck Wah; Tan, Han Yen; Liew, Oi Wah

2012-01-01

The use of different types of stains in the quantification of proteins separated on gels using electrophoresis offers the capability of deriving good outcomes in terms of linear dynamic range, sensitivity, and compatibility with specific proteins. An inexpensive, simple, and versatile lighting system based on liquid crystal display backlighting is…

One-step detection of microRNA with high sensitivity and specificity via target-triggered loop-mediated isothermal amplification (TT-LAMP).

PubMed

Sun, Yuanyuan; Tian, Hui; Liu, Chenghui; Sun, Yueying; Li, Zhengping

2017-10-05

A novel one-step microRNA assay is developed based on a target-triggered loop-mediated isothermal amplification (TT-LAMP) mechanism, which enables the accurate detection of as low as 100 aM (1 zmol) microRNA with simple one-step operation by using only one-type of DNA polymerase.

Direct detection and characterization of foot-and-mouth disease virus in East Africa using a field-ready real-time PCR platform.

PubMed

Howson, E L A; Armson, B; Lyons, N A; Chepkwony, E; Kasanga, C J; Kandusi, S; Ndusilo, N; Yamazaki, W; Gizaw, D; Cleaveland, S; Lembo, T; Rauh, R; Nelson, W M; Wood, B A; Mioulet, V; King, D P; Fowler, V L

2018-02-01

Effective control and monitoring of foot-and-mouth disease (FMD) relies upon rapid and accurate disease confirmation. Currently, clinical samples are usually tested in reference laboratories using standardized assays recommended by The World Organisation for Animal Health (OIE). However, the requirements for prompt and serotype-specific diagnosis during FMD outbreaks, and the need to establish robust laboratory testing capacity in FMD-endemic countries have motivated the development of simple diagnostic platforms to support local decision-making. Using a portable thermocycler, the T-COR™ 8, this study describes the laboratory and field evaluation of a commercially available, lyophilized pan-serotype-specific real-time RT-PCR (rRT-PCR) assay and a newly available FMD virus (FMDV) typing assay (East Africa-specific for serotypes: O, A, Southern African Territories [SAT] 1 and 2). Analytical sensitivity, diagnostic sensitivity and specificity of the pan-serotype-specific lyophilized assay were comparable to that of an OIE-recommended laboratory-based rRT-PCR (determined using a panel of 57 FMDV-positive samples and six non-FMDV vesicular disease samples for differential diagnosis). The FMDV-typing assay was able to correctly identify the serotype of 33/36 FMDV-positive samples (no cross-reactivity between serotypes was evident). Furthermore, the assays were able to accurately detect and type FMDV RNA in multiple sample types, including epithelial tissue suspensions, serum, oesophageal-pharyngeal (OP) fluid and oral swabs, both with and without the use of nucleic acid extraction. When deployed in laboratory and field settings in Tanzania, Kenya and Ethiopia, both assays reliably detected and serotyped FMDV RNA in samples (n = 144) collected from pre-clinical, clinical and clinically recovered cattle. These data support the use of field-ready rRT-PCR platforms in endemic settings for simple, highly sensitive and rapid detection and/or characterization of FMDV. © 2017 The Authors. Transboundary and Emerging Diseases Published by Blackwell Verlag GmbH.

Establishment and application of cross-priming isothermal amplification coupled with lateral flow dipstick (CPA-LFD) for rapid and specific detection of red-spotted grouper nervous necrosis virus.

PubMed

Su, Zi Dan; Shi, Cheng Yin; Huang, Jie; Shen, Gui Ming; Li, Jin; Wang, Sheng Qiang; Fan, Chao

2015-09-26

Red-spotted grouper nervous necrosis virus (RGNNV) is an important pathogen that causes diseases in many species of fish in marine aquaculture. The larvae and juveniles are more easily infected by RGNNV and the cumulative mortality is as high as 100 % after being infected with RGNNV. This virus imposes a serious threat to aquaculture of grouper fry. This study aimed to establish a simple, accurate and highly sensitive method for rapid detection of RGNNV on the spot. In this study, the primers specifically targeting RGNNV were designed and cross-priming isothermal amplification (CPA) system was established. The product amplified by CPA was detected through visualization with lateral flow dipstick (LFD). Three important parameters, including the amplification temperature, the concentration of dNTPs and the concentration of Mg(2+) for the CPA system, were optimized. The sensitivity and specificity of this method for RGNNV were tested and compared with those of the conventional RT-PCR and real-time quantitative RT-PCR (qRT-PCR). The optimized conditions for the CPA amplification system were determined as follows: the optimal amplification temperature, the optimized concentration of dNTPs and the concentration for Mg(2+) were 69 °C, 1.2 mmol/L and 5 mmol/L, respectively. The lowest limit of detection (LLOD) of this method for RGNNV was 10(1) copies/μL of RNA sample, which was 10 times lower than that of conventional RT-PCR and comparable to that of RT-qPCR. This method was specific for RGNNV in combination with SJNNV and had no cross-reactions with 8 types of virus and bacterial strains tested. This method was successfully applied to detect RGNNV in fish samples. This study established a CPA-LFD method for detection of RGNNV. This method is simple and rapid with high sensitivity and good specificity and can be widely applied for rapid detection of this virus on the spot.

Risk assessment of Pakistani individuals for diabetes (RAPID).

PubMed

Riaz, Musarrat; Basit, Abdul; Hydrie, Muhammad Zafar Iqbal; Shaheen, Fariha; Hussain, Akhtar; Hakeem, Rubina; Shera, Abdus Samad

2012-12-01

To develop and evaluate a risk score to predict people at high risk of developing type 2 diabetes in Pakistan. Cross sectional data regarding primary prevention of diabetes in Pakistan. Diabetes risk score was developed by using simple parameters namely age, waist circumference, and family history of diabetes. Odds ratios of the model were used to assign a score value for each variable and the diabetes risk score was calculated as the sum of those scores. We externally validated the score using two data from 1264 subjects and 856 subjects aged 25 years and above from two separate studies respectively. Validating this score using the first data from the second screening study gave an area under the receive operator characteristics curve [AROC] of 0.758. A cut point of 4 had a sensitivity of 47.0% and specificity of 88% and in the second data AROC is 0.7 with 44% sensitivity and 89% specificity. A simple diabetes risk score, based on a set of variables can be used for the identification of high risk individuals for early intervention to delay or prevent type 2 diabetes in Pakistani population. Copyright © 2012 Primary Care Diabetes Europe. Published by Elsevier Ltd. All rights reserved.

Rapid authentication of the precious herb saffron by loop-mediated isothermal amplification (LAMP) based on internal transcribed spacer 2 (ITS2) sequence

PubMed Central

Zhao, Mingming; Shi, Yuhua; Wu, Lan; Guo, Licheng; Liu, Wei; Xiong, Chao; Yan, Song; Sun, Wei; Chen, Shilin

2016-01-01

Saffron is one of the most expensive species of Chinese herbs and has been subjected to various types of adulteration because of its high price and limited production. The present study introduces a loop-mediated isothermal amplification (LAMP) technique for the differentiation of saffron from its adulterants. This novel technique is sensitive, efficient and simple. Six specific LAMP primers were designed on the basis of the nucleotide sequence of the internal transcribed spacer 2 (ITS2) nuclear ribosomal DNA of Crocus sativus. All LAMP amplifications were performed successfully, and visual detection occurred within 60 min at isothermal conditions of 65 °C. The results indicated that the LAMP primers are accurate and highly specific for the discrimination of saffron from its adulterants. In particular, 10 fg of genomic DNA was determined to be the limit for template accuracy of LAMP in saffron. Thus, the proposed novel, simple, and sensitive LAMP assay is well suited for immediate on-site discrimination of herbal materials. Based on the study, a practical standard operating procedure (SOP) for utilizing the LAMP protocol for herbal authentication is provided. PMID:27146605

Rapid authentication of the precious herb saffron by loop-mediated isothermal amplification (LAMP) based on internal transcribed spacer 2 (ITS2) sequence.

PubMed

Zhao, Mingming; Shi, Yuhua; Wu, Lan; Guo, Licheng; Liu, Wei; Xiong, Chao; Yan, Song; Sun, Wei; Chen, Shilin

2016-05-05

Saffron is one of the most expensive species of Chinese herbs and has been subjected to various types of adulteration because of its high price and limited production. The present study introduces a loop-mediated isothermal amplification (LAMP) technique for the differentiation of saffron from its adulterants. This novel technique is sensitive, efficient and simple. Six specific LAMP primers were designed on the basis of the nucleotide sequence of the internal transcribed spacer 2 (ITS2) nuclear ribosomal DNA of Crocus sativus. All LAMP amplifications were performed successfully, and visual detection occurred within 60 min at isothermal conditions of 65 °C. The results indicated that the LAMP primers are accurate and highly specific for the discrimination of saffron from its adulterants. In particular, 10 fg of genomic DNA was determined to be the limit for template accuracy of LAMP in saffron. Thus, the proposed novel, simple, and sensitive LAMP assay is well suited for immediate on-site discrimination of herbal materials. Based on the study, a practical standard operating procedure (SOP) for utilizing the LAMP protocol for herbal authentication is provided.

Development of Lateral Flow Immunoassay for Antigen Detection in Human Angiostrongylus cantonensis Infection

PubMed Central

Chen, Mu-Xin; Chen, Jia-Xu; Chen, Shao-Hong; Huang, Da-Na; Ai, Lin; Zhang, Ren-Li

2016-01-01

Angiostrongyliasis is difficult to be diagnosed for the reason that no ideal method can be used. Serologic tests require specific equipment and are not always available in poverty-stricken zone and are time-consuming. A lateral flow immunoassay (LFIA) may be useful for angiostrongyliasis control. We established a LFIA for the diagnosis of angiostrongyliasis based on 2 monoclonal antibodies (mAbs) against antigens of Angiostrongylus cantonensis adults. The sensitivity and specificity were 91.1% and 100% in LFIA, while those of commercial ELISA kit was 97.8% and 86.3%, respectively. Youden index was 0.91 in LFIA and 0.84 in commercial ELISA kit. LFIA showed detection limit of 1 ng/ml of A. cantonensis ES antigens. This LFIA was simple, rapid, highly sensitive and specific, which opened an alternative approach for the diagnosis of human angiostrongyliasis. PMID:27417097

Accuracy of simple urine tests for diagnosis of urinary tract infections in low-risk pregnant women.

PubMed

Feitosa, Danielle Cristina Alves; da Silva, Márcia Guimarães; de Lima Parada, Cristina Maria Garcia

2009-01-01

Anatomic and physiological alterations during pregnancy predispose pregnant women to urinary tract infections (UTI). This study aimed to identify the accuracy of the simple urine test for UTI diagnosis in low-risk pregnant women. Diagnostic test performance was conducted in Botucatu, SP, involving 230 pregnant women, between 2006 and 2008. Results showed 10% UTI prevalence. Sensitivity, specificity and accuracy of the simple urine test were 95.6%, 63.3% and 66.5%, respectively, in relation to UTI diagnoses. The analysis of positive (PPV) and negative (NPV) predictive values showed that, when a regular simple urine test was performed, the chance of UTI occurrence was small (NPV 99.2%). In view of an altered result for such a test, the possibility of UTI existence was small (PPV 22.4%). It was concluded that the accuracy of the simple urine test as a diagnostic means for UTI was low, and that performing a urine culture is essential for appropriate diagnosis.

Real-time fluorescence loop mediated isothermal amplification for the diagnosis of malaria.

PubMed

Lucchi, Naomi W; Demas, Allison; Narayanan, Jothikumar; Sumari, Deborah; Kabanywanyi, Abdunoor; Kachur, S Patrick; Barnwell, John W; Udhayakumar, Venkatachalam

2010-10-29

Molecular diagnostic methods can complement existing tools to improve the diagnosis of malaria. However, they require good laboratory infrastructure thereby restricting their use to reference laboratories and research studies. Therefore, adopting molecular tools for routine use in malaria endemic countries will require simpler molecular platforms. The recently developed loop-mediated isothermal amplification (LAMP) method is relatively simple and can be improved for better use in endemic countries. In this study, we attempted to improve this method for malaria diagnosis by using a simple and portable device capable of performing both the amplification and detection (by fluorescence) of LAMP in one platform. We refer to this as the RealAmp method. Published genus-specific primers were used to test the utility of this method. DNA derived from different species of malaria parasites was used for the initial characterization. Clinical samples of P. falciparum were used to determine the sensitivity and specificity of this system compared to microscopy and a nested PCR method. Additionally, directly boiled parasite preparations were compared with a conventional DNA isolation method. The RealAmp method was found to be simple and allowed real-time detection of DNA amplification. The time to amplification varied but was generally less than 60 minutes. All human-infecting Plasmodium species were detected. The sensitivity and specificity of RealAmp in detecting P. falciparum was 96.7% and 91.7% respectively, compared to microscopy and 98.9% and 100% respectively, compared to a standard nested PCR method. In addition, this method consistently detected P. falciparum from directly boiled blood samples. This RealAmp method has great potential as a field usable molecular tool for diagnosis of malaria. This tool can provide an alternative to conventional PCR based diagnostic methods for field use in clinical and operational programs.

Development of an Indirect ELISA for Serological Diagnosis of Bovine herpesvirus 5

PubMed Central

Campos, Fabrício S.; da Rosa, Matheus C.; Finger, Paula F.; de Oliveira, Patricia D.; Conceição, Fabricio R.; Fischer, Geferson; Roehe, Paulo M.; Leite, Fábio P. L.

2016-01-01

Bovine herpesviruses 1 and 5 (BoHV-1 and BoHV-5) are economically important pathogens, associated with a variety of clinical syndromes, including respiratory and genital disease, reproductive failure and meningoencephalitis. The standard serological assay to diagnose BoHV-1 and BoHV-5 infections is the virus neutralization test (VNT), a time consuming procedure that requires manipulation of infectious virus. In the present study a highly sensitive and specific single dilution indirect ELISA was developed using recombinant glycoprotein D from BoHV-5 as antigen (rgD5ELISA). Bovine serum samples (n = 450) were screened by VNT against BoHV-5a and by rgD5ELISA. Compared with the VNT, the rgD5ELISA demonstrated accuracy of 99.8%, with 100% sensitivity, 96.7% specificity and coefficient of agreement between the tests of 0.954. The rgD5ELISA described here shows excellent agreement with the VNT and is shown to be a simple, convenient, specific and highly sensitive virus-free assay for detection of serum antibodies to BoHV-5. PMID:26866923

Criteria To Screen for Chronic Sinonasal Disease

PubMed Central

Dixon, Anne E.; Sugar, Elizabeth A.; Zinreich, S. James; Slavin, Raymond G.; Corren, Jonathan; Naclerio, Robert M.; Ishii, Masaru; Cohen, Rubin I.; Brown, Ellen D.; Wise, Robert A.; Irvin, Charles G.

2009-01-01

Background: Sinusitis and rhinitis are associated with uncontrolled asthma. There are no simple, validated tools to screen for these diseases. The objective of this study was to assess instruments to assist in the diagnosis of chronic sinonasal disease. Methods: Participants without acute sinonasal symptoms underwent an extensive evaluation. The results were submitted to an expert panel that used the Delphi method to achieve consensus. Using the consensus diagnosis of the panel, we determined the sensitivity and specificity of test procedures to diagnose chronic sinonasal disease. We determined the reproducibility of the most sensitive and specific instrument in a separate cohort. Results: Fifty-nine participants were evaluated, and the expert panel reached consensus for all (42 participants with chronic sinonasal disease, 17 participants without chronic sinonasal disease). A six-item questionnaire based on the frequency of nasal symptoms was the most sensitive tool used to diagnose sinonasal disease (minimum specificity, 0.90). Reproducibility testing in a separate cohort of 63 participants (41 chronic sinonasal disease with asthma, 22 chronic sinonasal disease without asthma) showed a concordance correlation coefficient of 0.91 (95% CI, 0.85 to 0.94) when this questionnaire was limited to five items (ie, excluding a question on smell). This five-item questionnaire had a sensitivity of 0.90 (95% CI, 0.77 to 0.97), a specificity of 0.94 (95% CI, 0.71 to 1.00), and an area under the receiver operating characteristic curve of 0.97 (95% CI, 0.93 to 1.0). Sinus CT scans and nasal endoscopy lacked sensitivity for use in the diagnosis of chronic sinonasal disease. Conclusions: We have developed a sensitive, specific, and reproducible instrument to screen for chronic sinonasal disease. Validation studies of this five-item questionnaire are needed, including in patients with asthma. PMID:19581356

Development and Validation of a Simple Risk Score for Undiagnosed Type 2 Diabetes in a Resource-Constrained Setting

PubMed Central

Gilman, Robert H.; Sanchez-Abanto, Jose R.; Study Group, CRONICAS Cohort

2016-01-01

Objective. To develop and validate a risk score for detecting cases of undiagnosed diabetes in a resource-constrained country. Methods. Two population-based studies in Peruvian population aged ≥35 years were used in the analysis: the ENINBSC survey (n = 2,472) and the CRONICAS Cohort Study (n = 2,945). Fasting plasma glucose ≥7.0 mmol/L was used to diagnose diabetes in both studies. Coefficients for risk score were derived from the ENINBSC data and then the performance was validated using both baseline and follow-up data of the CRONICAS Cohort Study. Results. The prevalence of undiagnosed diabetes was 2.0% in the ENINBSC survey and 2.9% in the CRONICAS Cohort Study. Predictors of undiagnosed diabetes were age, diabetes in first-degree relatives, and waist circumference. Score values ranged from 0 to 4, with an optimal cutoff ≥2 and had a moderate performance when applied in the CRONICAS baseline data (AUC = 0.68; 95% CI: 0.62–0.73; sensitivity 70%; specificity 59%). When predicting incident cases, the AUC was 0.66 (95% CI: 0.61–0.71), with a sensitivity of 69% and specificity of 59%. Conclusions. A simple nonblood based risk score based on age, diabetes in first-degree relatives, and waist circumference can be used as a simple screening tool for undiagnosed and incident cases of diabetes in Peru. PMID:27689096

Near instrument-free, simple molecular device for rapid detection of herpes simplex viruses.

PubMed

Lemieux, Bertrand; Li, Ying; Kong, Huimin; Tang, Yi-Wei

2012-06-01

The first near instrument-free, inexpensive and simple molecular diagnostic device (IsoAmp HSV, BioHelix Corp., MA, USA) recently received US FDA clearance for use in the detection of herpes simplex viruses (HSV) in genital and oral lesion specimens. The IsoAmp HSV assay uses isothermal helicase-dependent amplification in combination with a disposable, hermetically-sealed, vertical-flow strip identification. The IsoAmp HSV assay has a total test-to-result time of less than 1.5 h by omitting the time-consuming nucleic acid extraction. The diagnostic sensitivity and specificity are comparable to PCR and are superior to culture-based methods. The near instrument-free, rapid and simple characteristics of the IsoAmp HSV assay make it potentially suitable for point-of-care testing.

Rapid, Fully Automated Digital Immunoassay for p24 Protein with the Sensitivity of Nucleic Acid Amplification for Detecting Acute HIV Infection.

PubMed

Cabrera, Carlos; Chang, Lei; Stone, Mars; Busch, Michael; Wilson, David H

2015-11-01

Nucleic acid testing (NAT) has become the standard for high sensitivity in detecting low levels of virus. However, adoption of NAT can be cost prohibitive in low-resource settings where access to extreme sensitivity could be clinically advantageous for early detection of infection. We report development and preliminary validation of a simple, low-cost, fully automated digital p24 antigen immunoassay with the sensitivity of quantitative NAT viral load (NAT-VL) methods for detection of acute HIV infection. We developed an investigational 69-min immunoassay for p24 capsid protein for use on a novel digital analyzer on the basis of single-molecule-array technology. We evaluated the assay for sensitivity by dilution of standardized preparations of p24, cultured HIV, and preseroconversion samples. We characterized analytical performance and concordance with 2 NAT-VL methods and 2 contemporary p24 Ag/Ab combination immunoassays with dilutions of viral isolates and samples from the earliest stages of HIV infection. Analytical sensitivity was 0.0025 ng/L p24, equivalent to 60 HIV RNA copies/mL. The limit of quantification was 0.0076 ng/L, and imprecision across 10 runs was <10% for samples as low as 0.09 ng/L. Clinical specificity was 95.1%. Sensitivity concordance vs NAT-VL on dilutions of preseroconversion samples and Group M viral isolates was 100%. The digital immunoassay exhibited >4000-fold greater sensitivity than contemporary immunoassays for p24 and sensitivity equivalent to that of NAT methods for early detection of HIV. The data indicate that NAT-level sensitivity for acute HIV infection is possible with a simple, low-cost digital immunoassay. © 2015 American Association for Clinical Chemistry.

Comparison between Surrogate Indexes of Insulin Sensitivity/Resistance and Hyperinsulinemic Euglycemic Glucose Clamps in Rhesus Monkeys

PubMed Central

Lee, Ho-Won; Muniyappa, Ranganath; Yan, Xu; Yue, Lilly Q.; Linden, Ellen H.; Chen, Hui; Hansen, Barbara C.

2011-01-01

The euglycemic glucose clamp is the reference method for assessing insulin sensitivity in humans and animals. However, clamps are ill-suited for large studies because of extensive requirements for cost, time, labor, and technical expertise. Simple surrogate indexes of insulin sensitivity/resistance including quantitative insulin-sensitivity check index (QUICKI) and homeostasis model assessment (HOMA) have been developed and validated in humans. However, validation studies of QUICKI and HOMA in both rats and mice suggest that differences in metabolic physiology between rodents and humans limit their value in rodents. Rhesus monkeys are a species more similar to humans than rodents. Therefore, in the present study, we evaluated data from 199 glucose clamp studies obtained from a large cohort of 86 monkeys with a broad range of insulin sensitivity. Data were used to evaluate simple surrogate indexes of insulin sensitivity/resistance (QUICKI, HOMA, Log HOMA, 1/HOMA, and 1/Fasting insulin) with respect to linear regression, predictive accuracy using a calibration model, and diagnostic performance using receiver operating characteristic. Most surrogates had modest linear correlations with SIClamp (r ≈ 0.4–0.64) with comparable correlation coefficients. Predictive accuracy determined by calibration model analysis demonstrated better predictive accuracy of QUICKI than HOMA and Log HOMA. Receiver operating characteristic analysis showed equivalent sensitivity and specificity of most surrogate indexes to detect insulin resistance. Thus, unlike in rodents but similar to humans, surrogate indexes of insulin sensitivity/resistance including QUICKI and log HOMA may be reasonable to use in large studies of rhesus monkeys where it may be impractical to conduct glucose clamp studies. PMID:21209021

High-resolution mapping of transcription factor binding sites on native chromatin

PubMed Central

Kasinathan, Sivakanthan; Orsi, Guillermo A.; Zentner, Gabriel E.; Ahmad, Kami; Henikoff, Steven

2014-01-01

Sequence-specific DNA-binding proteins including transcription factors (TFs) are key determinants of gene regulation and chromatin architecture. Formaldehyde cross-linking and sonication followed by Chromatin ImmunoPrecipitation (X-ChIP) is widely used for profiling of TF binding, but is limited by low resolution and poor specificity and sensitivity. We present a simple protocol that starts with micrococcal nuclease-digested uncross-linked chromatin and is followed by affinity purification of TFs and paired-end sequencing. The resulting ORGANIC (Occupied Regions of Genomes from Affinity-purified Naturally Isolated Chromatin) profiles of Saccharomyces cerevisiae Abf1 and Reb1 provide highly accurate base-pair resolution maps that are not biased toward accessible chromatin, and do not require input normalization. We also demonstrate the high specificity of our method when applied to larger genomes by profiling Drosophila melanogaster GAGA Factor and Pipsqueak. Our results suggest that ORGANIC profiling is a widely applicable high-resolution method for sensitive and specific profiling of direct protein-DNA interactions. PMID:24336359

The sensitivity and specificity of subjective memory complaints and the subjective memory rating scale, deterioration cognitive observee, mini-mental state examination, six-item screener and clock drawing test in dementia screening.

PubMed

Ramlall, S; Chipps, J; Bhigjee, A I; Pillay, B J

2013-01-01

The effectiveness of dementia screening depends on the availability of suitable screening tools with good sensitivity and specificity to confidently distinguish normal age-related cognitive decline from dementia. The aim of this study was to evaluate the discriminant validity of 7 screening measures for dementia. A sample of 140 participants aged ≥60 years living in a residential facility for the aged were assessed clinically and assigned caseness for dementia using the Diagnostic and Statistical Manual of Mental Disorders, 4th edition, text revised diagnostic criteria. Sensitivity and specificity of a selection of the following screening measures were tested using receiver operating characteristic (ROC) analysis for individual and combined tests: the Mini-Mental State Examination (MMSE), Six-Item Screener (SIS), Subjective Memory Complaint, Subjective Memory Complaint Clinical (SMCC), Subjective Memory Rating Scale (SMRS), Deterioration Cognitive Observee (DECO) and the Clock Drawing Test (CDT). Using ROC analyses, the SMCC, MMSE and CDT were found to be 'moderately accurate' in screening for dementia with an area under the curve (AUC) >0.70. The AUCs for the SIS (0.526), SMRS (0.661) and DECO (0.687) classified these measures as being 'less accurate'. At recommended cutoff scores, the SMCC had a sensitivity of 90.9% and specificity of 45.7%; the MMSE had a sensitivity of 63.6% and a specificity of 76.0%, and the CDT had a sensitivity of 44.4% and a specificity of 88.9%. Combining the SMCC and MMSE did not improve their predictive power except for a modest increase when using the sequential rule. The SMCC is composed of valid screening questions that have high sensitivity, are simple to administer and ideal for administration at the community or primary health care level as a first level of 'rule-out' screening. The MMSE can be included at a second stage of screening at the general hospital level and the CDT in specialist clinical settings. Sequential use of the SMCC and MMSE will improve the specificity of the former and the sensitivity of the latter. Copyright © 2013 S. Karger AG, Basel.

A simple semi-rapid HIV-1&2 confirmatory immunoassay using magnetic particles.

PubMed

Sommerfelt, Maja A; Ohlsson, Irene; Flolid, Irene; Thorstensson, Rigmor; Sørensen, Birger

2004-02-01

The Bionor HIV-1&2 Confirmatory Test is a semi-rapid simple immunoassay based on magnetic particles for the confirmation of serological status to human immunodeficiency virus (HIV). The specificity and sensitivity of this assay was evaluated by comparison with the Diagnostic Biotechnology HIV-1 Western blot (WB) 2.2 and the HIV-2/SBL-6669 WB. Bionor's confirmatory test demonstrated 98% specificity when testing sero-negative blood donors and false positive sera in screening tests compared to 81.5 and 71.6%, respectively, using the HIV-1 WB. The sensitivity of this assay for HIV-1 antibody positive sera was 97.9% compared to the WB which was 99.5%. When testing confirmed HIV-2 antibody positive samples, 2/100 scored negative using this confirmatory test similar to other HIV-2 peptide-based line immunoassays available commercially, whilst 8/100 were indeterminate reacting to HIV-2 membrane antigens only. Bionor's confirmatory test detected HIV-1 seropositivity earlier than the WB in longitudinal seroconversion panels and could discriminate between HIV-1 and -2 infection. The number of indeterminate responses was generally reduced significantly using Bionor's confirmatory test compared to the HIV-1 WB. The greater specificity, speed and ease of interpretation of Bionor's confirmatory test renders it an attractive and cost effective alternative to the WB for confirming HIV serological status worldwide.

Incorporating uncertainty into medical decision making: an approach to unexpected test results.

PubMed

Bianchi, Matt T; Alexander, Brian M; Cash, Sydney S

2009-01-01

The utility of diagnostic tests derives from the ability to translate the population concepts of sensitivity and specificity into information that will be useful for the individual patient: the predictive value of the result. As the array of available diagnostic testing broadens, there is a temptation to de-emphasize history and physical findings and defer to the objective rigor of technology. However, diagnostic test interpretation is not always straightforward. One significant barrier to routine use of probability-based test interpretation is the uncertainty inherent in pretest probability estimation, the critical first step of Bayesian reasoning. The context in which this uncertainty presents the greatest challenge is when test results oppose clinical judgment. It is this situation when decision support would be most helpful. The authors propose a simple graphical approach that incorporates uncertainty in pretest probability and has specific application to the interpretation of unexpected results. This method quantitatively demonstrates how uncertainty in disease probability may be amplified when test results are unexpected (opposing clinical judgment), even for tests with high sensitivity and specificity. The authors provide a simple nomogram for determining whether an unexpected test result suggests that one should "switch diagnostic sides.'' This graphical framework overcomes the limitation of pretest probability uncertainty in Bayesian analysis and guides decision making when it is most challenging: interpretation of unexpected test results.

A Label-Free Aptasensor for Ochratoxin a Detection Based on the Structure Switch of Aptamer.

PubMed

Liu, Feng; Ding, Ailing; Zheng, Jiushang; Chen, Jiucun; Wang, Bin

2018-06-01

A label-free sensing platform is developed based on switching the structure of aptamer for highly sensitive and selective fluorescence detection of ochratoxin A (OTA). OTA induces the structure of aptamer, transforms into G-quadruplex and produces strong fluorescence in the presence of zinc(II)-protoporphyrin IX probe due to the specific bind to G-quadruplex. The simple method exhibits high sensitivity towards OTA with a detection limit of 0.03 nM and excellent selectivity over other mycotoxins. In addition, the successful detection of OTA in real samples represents a promising application in food safety.

An Incidence Loss Model for Wave Rotors with Axially Aligned Passages

NASA Technical Reports Server (NTRS)

Paxson, Daniel E.

1998-01-01

A simple mathematical model is described to account for the losses incurred when the flow in the duct (port) of a wave rotor is not aligned with the passages. The model, specifically for wave rotors with axially aligned passages, describes a loss mechanism which is sensitive to incident flow angle and Mach number. Implementation of the model in a one-dimensional CFD based wave rotor simulation is presented. Comparisons with limited experimental results are consistent with the model. Sensitivity studies are presented which highlight the significance of the incidence loss relative to other loss mechanisms in the wave rotor.

A novel diagnostic biomarker panel for obesity-related nonalcoholic steatohepatitis (NASH).

PubMed

Younossi, Zobair M; Jarrar, Mohammed; Nugent, Clare; Randhawa, Manpreet; Afendy, Mariam; Stepanova, Maria; Rafiq, Nila; Goodman, Zachary; Chandhoke, Vikas; Baranova, Ancha

2008-11-01

Within the spectrum of nonalcoholic fatty liver disease (NAFLD), only patients with nonalcoholic steatohepatitis (NASH) show convincing evidence for progression. To date, liver biopsy remains the gold standard for the diagnosis of NASH; however, liver biopsy is expensive and associated with a small risk, emphasizing the urgent need for noninvasive diagnostic biomarkers. Recent findings suggest a role for apoptosis and adipocytokines in the pathogenesis of NASH. The aim of this study was to develop a noninvasive diagnostic biomarker for NASH. The study included 101 patients with liver biopsies who were tested with enzyme-linked immunosorbent assay (ELISA)-based assays. Of these, 69 were included in the biomarker development set and 32 were included in the biomarker validation set. Clinical data and serum samples were collected at the time of biopsy. Fasting serum samples were assayed for adiponectin, resistin, insulin, glucose, TNF-alpha, IL-6, IL-8, cytokeratin CK-18 (M65 antigen), and caspase-cleaved CK-18 (M30 antigen). Data analysis revealed that the levels of M30 antigen (cleaved CK-18) predicted histological NASH with 70% sensitivity and 83.7% specificity and area under the curve (AUC) = 0.711, p < 10(-4), whereas the predictive value of the levels of intact CK-18 (M65) was higher (63.6% sensitivity and 89.4% specificity and AUC = 0.814, p < 10(-4)). Histological NASH could be predicted by a combination of Cleaved CK-18, a product of the subtraction of Cleaved CK-18 level from intact CK-18 level, serum adiponectin, and serum resistin with a sensitivity of 95.45% sensitivity, specificity of 70.21%, and AUC of 0.908 (p < 10(-4)). Blinded validation of this model confirmed its reliability for separating NASH from simple steatosis. Four ELISA-based tests were combined to form a simple diagnostic biomarker for NASH.

Development and evaluation of a polydiacetylene based biosensor for the detection of H5 influenza virus.

PubMed

Jiang, Lixiang; Luo, Jing; Dong, Wenjie; Wang, Chengmin; Jin, Wen; Xia, Yuetong; Wang, Haijing; Ding, Hua; Jiang, Long; He, Hongxuan

2015-07-01

H5N1 avian influenza has caused serious economic losses as well as posed significant threats to public health, agriculture and wildlife. It is important to develop a rapid, sensitive and specific detection platform suitable for disease surveillance and control. In this study, a highly sensitive, specific and rapid biosensor based on polydiacetylene was developed for detecting H5 influenza virus. The polydiacetylene based biosensor was produced from an optimized ratio of 10,12-pentacosadiynoic acid and 1,2-dimyristoyl-sn-glycero-3-phosphocholine, with the anti-H5 influenza antibody embedded onto the vesicle surface. The optimized polydiacetylene vesicle could detect H5 influenza virus sensitively with a detection limit of 0.53 copies/μL, showing a dramatic blue-to-red color change that can be observed directly by the naked eye and recorded by a UV-vis spectrometer. The sensitivity, specificity and accuracy of the biosensor were also evaluated. The sensor could specifically differentiate H5 influenza virus from H3 influenza virus, Newcastle disease virus and porcine reproductive and respiratory syndrome virus. Detection using tracheal swabs was in accord with virus isolation results, and comparable to the RT-PCR method. These results offer the possibility and potential of simple polydiacetylene based bio-analytical method for influenza surveillance. Copyright © 2015 Elsevier B.V. All rights reserved.

Specific, sensitive, and rapid assay for human immunodeficiency virus type 1 pol mutations associated with resistance to zidovudine and didanosine.

PubMed Central

Frenkel, L M; Wagner, L E; Atwood, S M; Cummins, T J; Dewhurst, S

1995-01-01

The effectiveness of antiretroviral therapy may be limited by the development of human immunodeficiency virus type 1 (HIV-1) resistance. Monitoring for resistance will perhaps allow changes in therapy prior to deterioration in the patient's clinical or immunologic status. Our objective was to develop a rapid, specific, and sensitive genotypic assay for HIV-1 resistance to zidovudine (ZDV) and didanosine (ddI) which is simple to perform. In our assay the DNA of HIV-1 pol was amplified by PCR using two sets of nested oligonucleotide primers. Mutations of reverse transcriptase (RT) encoding amino acids (aa) 74 and 41, 70, and 215 which have been associated with HIV-1 resistance to ddI and ZDV, respectively, were detected with a ligase detection reaction (LDR) and indicated colorimetrically. The RT genotypes of 35 patient specimens (140 codons) blindly assessed for these mutations were in agreement by PCR-LDR and by dideoxynucleotide sequencing. To evaluate the limits of the assay, other specimens with mutations close to the ligation site were evaluated by PCR-LDR. The assay was sensitive and specific for all specimens except when mutations occurred within 2 bases on either side of the ligation site. In summary, this PCR-LDR assay specifically, sensitively, and rapidly detected pol mutations (RT aa 74, 41, 70, and 215) associated with HIV-1 resistance to ddI and ZDV. PMID:7714190

Lyme Borreliosis--the Utility of Improved Real-Time PCR Assay in the Detection of Borrelia burgdorferi Infections.

PubMed

Bil-Lula, Iwona; Matuszek, Patryk; Pfeiffer, Thomas; Woźniak, Mieczysław

2015-01-01

Infections of Borrelia burgdorferi sensu lato reveal clinical manifestations affecting numerous organs and tissues. The standard diagnostic procedure of these infections is quite simple if a positive history of tick exposure or typical erythema migrans appears. Lack of unequivocal clinical symptoms creates the necessity for further evaluation with laboratory tests. This study discusses the utility of a novel, improved, well-optimized, sensitive and highly specific quantitative real-time PCR assay for the diagnostics of infections caused by Borrelia burgdorferi sensu lato. We designed an improved, specific, highly sensitive real-time quantitative polymerase chain reaction (RQ-PCR) assay for the detection and quantification of all Borrelia burgdorferi genotypes. A wide validation effort was undertaken to ensure confidence in the highly sensitive and specific detection of B. burgdorferi. Due to high sensitivity and great specificity, as low as 1.6×10² copies of Borrelia per mL of whole blood could be detected. As much as 12 (3%) negative ELISA IgM results, 14 (2.8%) negative results of Line blot IgM, 11 (3.1%) and 7 (2.7%) of negative ELISA IgG and Line blot IgG results, respectively, were positive in real-time PCR. The data in this study confirms the high positive predictive value of real-time PCR test in the detection of Borrelia infections.

Development of a rapid and visual nucleotide detection method for a Chinese epidemic strain of Orientia tsutsugamushi based on recombinase polymerase amplification assay and lateral flow test.

PubMed

Qi, Yong; Yin, Qiong; Shao, Yinxiu; Cao, Min; Li, Suqin; Chen, Hongxia; Shen, Wanpeng; Rao, Jixian; Li, Jiameng; Li, Xiaoling; Sun, Yu; Lin, Yu; Deng, Yi; Zeng, Wenwen; Zheng, Shulong; Liu, Suyun; Li, Yuexi

2018-05-01

Orientia tsutsugamushi is an obligate intracellular pathogen that causes scrub typhus. Diagnosing scrub typhus remains a challenge, and a sensitive, specific, simple, and rapid diagnostic test is still needed. A recombinase polymerase amplification (RPA) assay combined with a lateral flow (LF) test targeting the 56-kDa gene of a Karp-like strain of O. tsutsugamushi was developed and optimized. The detection limits, sensitivity, specificity, and simulative clinical performance were evaluated. Primers and probe were screened to establish the RPA assay, and the reaction conditions were optimized. The detection limit was 10 copies/reaction in detecting plasmid DNA and 12 copies/reaction in detecting genomic DNA. The RPA-LF method could differentiate O. tsutsugamushi from other phylogenetically related bacteria. The sensitivity was 100% and specificity was over 90%, when evaluated using infected animal samples or simulative clinical samples. Furthermore, the method was completed in 20min at 37°C followed by a 3-5min incubation at room temperature for the development of an immunochromatographic strip, and the results could be determined visually. This method is promising for wide-ranging use in basic medical units considering that it requires minimal instruments and infrastructure and is highly time-efficient, sensitive, and specific for diagnosing scrub typhus. Copyright © 2018 The Authors. Published by Elsevier Ltd.. All rights reserved.

Relapses vs. reactions in multibacillary leprosy: proposal of new relapse criteria.

PubMed

Linder, Katharina; Zia, Mutaher; Kern, Winfried V; Pfau, Ruth K M; Wagner, Dirk

2008-03-01

To compare a new scoring system for multibacillary (MB) leprosy relapses, which combines time factor, risk factors and clinical presentation at relapse, to WHO criteria. Data were collected on all relapses diagnosed between 1998 and 2004 at the Marie-Adelaide-Centre in Karachi, Pakistan, including case histories, clinical manifestations, follow-up, bacterial indices, treatment and contacts. For the diagnosis of MB relapses a simple scoring system was developed and validated on a data-set of mouse foot pads (MFP)-confirmed relapses (Leprosy Reviews, 76, 2005, 241). Its sensitivity was further evaluated in the Karachi relapse cohort. The P-value was calculated with McNemar's test with continuity correction. The new scoring system that combines time factor, risk factors and clinical presentation at relapse had a higher sensitivity in MFP-confirmed relapses than the WHO-criteria (95%vs. 65%, P < 0.01). The sensitivity of the scoring system was also significantly higher than the WHO criteria in the 57 cases of MB-relapses diagnosed in Karachi (72%vs. 54%, P < 0.05). This new simple scoring system for diagnosing MB-relapses in leprosy should be further validated in a prospective study to confirm its superior sensitivity and to evaluate the specificity of these criteria by using MFP-confirmation for patients presenting with signs of activity after treatment.

Effect of noisy stimulation on neurobiological sensitization systems and its role for normal and pathological physiology

NASA Astrophysics Data System (ADS)

Huber, Martin; Braun, Hans; Krieg, J.\\:Urgen-Christian

2004-03-01

Sensitization is discussed as an important phenomenon playing a role in normal physiology but also with respect to the initiation and progression of a variety of neuropsychiatric disorders such as epilepsia, substance-related disorders or recurrent affective disorders. The relevance to understand the dynamics of sensitization phenomena is emphasized by recent findings that even single stimulations can induce longlasting changes in biological systems. To address specific questions associated with the sensitization dynamics, we use a computational approach and develop simple but physiologically-plausible models. In the present study we examine the effect of noisy stimulation on sensitization development in the model. We consider sub- and suprathresold stimulations with varying noise intensities and determine as response measures the (i) absolute number of stimulus-induced sensitzations and (ii) the temporal relsation of stimulus-sensitization coupling. The findings indicate that stochastic effects including stochastic resonance might well contribute to the physiology of sensitization mechanisms under both nomal and pathological conditions.

A technique to improve diagnostic information from fine-needle aspirations: immunohistochemistry on cytoscrape.

PubMed

Skov, Birgit Guldhammer; Kiss, Katalin; Ramsted, Julie; Linnemann, Dorte

2009-04-25

Cytologic examination of fine-needle aspiration (FNA) material is being used increasingly for the diagnosis of pulmonary lesions. Accurate distinction between nonsmall cell lung cancer (NSCLC), including subgroups, and small cell lung cancer and between primary lung cancer and metastases has therapeutic impact. However, the distinction between these groups may be difficult on smears. In this report, the authors describe a simple method, called cytoscrape (CS), which can be used on virtually any smear to produce material useful for ancillary methods, including immunohistochemistry. Aspirates from 47 patients who had possible malignant infiltrates identified on computed tomography scans of the chest were included. Smears were stained by May-Grunwald-Giemsa and Diff-Quick for diagnostic purposes. CS material was obtained by gently scraping cells off the slides. Clots were made, and the sections were stained for thyroid transcription factor-1 (TTF-1) and mucin. The utility of the CS technique was evaluated by assessing the sensitivity and specificity of the method and by quantifying the extra diagnostic information obtained by the method relative to smears alone. Malignant tumor cells in the CS material were identified in 43 aspirates (91%). Both the sensitivity and the specificity for TTF-1 were 100%. The sensitivity for mucin was 60%, and the specificity for mucin was 100%. The diagnoses made on smears were improved by CS in 31 patients (72%), in that more precise separation of subgroups of NSCLC was possible or information on primary tumors was obtained. The CS technique improved the diagnostic information from FNA in a clinically relevant way. The method is simple, quick, and inexpensive. (c) 2009 American Cancer Society.

Wipe sampling for nicotine as a marker of thirdhand tobacco smoke contamination on surfaces in homes, cars, and hotels.

PubMed

Quintana, Penelope J E; Matt, Georg E; Chatfield, Dale; Zakarian, Joy M; Fortmann, Addie L; Hoh, Eunha

2013-09-01

Secondhand smoke contains a mixture of pollutants that can persist in air, dust, and on surfaces for months or longer. This persistent residue is known as thirdhand smoke (THS). Here, we detail a simple method of wipe sampling for nicotine as a marker of accumulated THS on surfaces. We analyzed findings from 5 real-world studies to investigate the performance of wipe sampling for nicotine on surfaces in homes, cars, and hotels in relation to smoking behavior and smoking restrictions. The intraclass correlation coefficient for side-by-side samples was 0.91 (95% CI: 0.87-0.94). Wipe sampling for nicotine reliably distinguished between private homes, private cars, rental cars, and hotels with and without smoking bans and was significantly positively correlated with other measures of tobacco smoke contamination such as air and dust nicotine. The sensitivity and specificity of possible threshold values (0.1, 1, and 10 μg/m(2)) were evaluated for distinguishing between nonsmoking and smoking environments. Sensitivity was highest at a threshold of 0.1 μg/m(2), with 74%-100% of smoker environments showing nicotine levels above threshold. Specificity was highest at a threshold of 10 μg/m(2), with 81%-100% of nonsmoker environments showing nicotine levels below threshold. The optimal threshold will depend on the desired balance of sensitivity and specificity and on the types of smoking and nonsmoking environments. Surface wipe sampling for nicotine is a reliable, valid, and relatively simple collection method to quantify THS contamination on surfaces across a wide range of field settings and to distinguish between nonsmoking and smoking environments.

A simple and rapid creatinine sensing via DLS selectivity, using calix[4]arene thiol functionalized gold nanoparticles.

PubMed

Sutariya, Pinkesh G; Pandya, Alok; Lodha, Anand; Menon, Shobhana K

2016-01-15

A new, simple, ultra-sensitive and selective approach has been reported for the "on spot" colorimetric detection of creatinine based on calix[4]arene functionalized gold nanoparticles (AuNPs) with excellent discrimination in the presence of other biomolecules. The lower detection limit of the method is 2.16nM. The gold nanoparticles and p-tert-butylcalix[4]arene were synthesized by microwave assisted method. Specifically, in our study, we used dynamic light scattering (DLS) which is a powerful method for the determination of small changes in particle size, improved selectivity and sensitivity of the creatinine detection system over colorimetric method. The nanoassembly is characterized by Transmission electron microscopy (TEM), DLS, UV-vis and ESI-MS spectroscopy, which demonstrates the binding affinity due its ability of hydrogen bonding and electrostatic interaction between -NH group of creatinine and pSDSC4. It exhibits fast response time (<60s) to creatinine and has long shelf-life (>5 weeks). The developed pSDSC4-AuNPs based creatinine biosensor will be established as simple, reliable and accurate tool for the determination of creatinine in human urine samples. Copyright © 2015 Elsevier B.V. All rights reserved.

Diagnostic performance of serological tests to detect antibodies against acute scrub typhus infection in central India.

PubMed

Pote, Kiran; Narang, Rahul; Deshmukh, Pradeep

2018-01-01

Differentiating scrub typhus from other acute febrile illness is difficult due to non specificity of clinical symptoms and relative absence of eschar in Indian population. The diagnosis thus relies mainly on laboratory tests. Antibody based serological tests are mainstay of scrub typhus diagnosis. Here, we evaluated the diagnostic performance of IgM ELISA, IgM IFA and ICT to detect antibodies against O. tsutsugamushi in acute serum of febrile patients. The serum samples from 600 randomly selected patients suffering from acute undifferentiated fever were tested by all the three tests mentioned above. We used latent class analysis to generate unbiased results as all the tests for scrub typhus diagnosis are imperfect and none of them can be considered as reference standard. We found that IgM ELISA with cutoff titer 0.5 OD has high diagnostic accuracy (sensitivity 99.9% and specificity 99.15) than IgM IFA (sensitivity 96.8% and specificity 99.7%) for scrub typhus diagnosis. ICT used in our study had very high specificity 100% but low sensitivity (38%) which would limit its use for acute serum samples. ICT being a screening or point of care test, has to be more sensitive while some compromise with specificity is affordable. Hence, optimal cutoff for ICT should be evaluated under different settings. IgM ELISA being simple and affordable could be an alternative diagnostic test to IgM IFA which is subjective and costly.

Comparison of methylene blue/gentian violet stain to Gram's stain for the rapid diagnosis of gonococcal urethritis in men.

PubMed

Taylor, Stephanie N; DiCarlo, Richard P; Martin, David H

2011-11-01

We compared a simple, one-step staining procedure using a mixture of methylene blue and gentian violet to Gram stain for the detection of gonococcal urethritis. The sensitivity and specificity of both Gram stain and methylene blue/gentian violet stain were 97.3% and 99.6%, respectively. There was a 100% correlation between the 2 methods.

Specificity Bio-identification of CNT-Based Transistor

NASA Astrophysics Data System (ADS)

Wang, Sheng-Yu; Wu, Hue-Min

2017-12-01

In this research, we report a simple and general approach to π-π stacking functionalization of the sidewalls of CNTs by 1-pyrenebutanoic acid, succinimidyl ester (PSE), and subsequent immobilization of insulin-like growth factor 1 receptor (IGF1R) onto SWNTs with a high degree of control and specificity. The selection of PSE provides visualization and characterization of individual CNTs based on its strong luminescence. In addition, we designed a simple and efficient electrode with a staggered pattern to increase the effect of electrophoresis by using electric field for the macroscopic alignment of CNTs to complete a field-effect device for CNT-based biosensors. Scanning Electron Microscopy (SEM) was used to investigate the morphology of the biosensors. The results of four-point probe method demonstrated high selectivity and sensitivity of detection. The functionalization of SWNTs was investigated by Fourier transform infrared spectroscopy (FTIR). Experimental results imply that specific binding between IGF1R and its specific mAb results in a dramatic change in electrical current of CNT-based devices, and suggest that the devices are very promising biosensor candidates to detect circulating cancer cells.

Validation of the Performance of International Ovarian Tumor Analysis (IOTA) Methods in the Diagnosis of Early Stage Ovarian Cancer in a Non-Screening Population.

PubMed

Froyman, Wouter; Wynants, Laure; Landolfo, Chiara; Bourne, Tom; Valentin, Lil; Testa, Antonia; Sladkevicius, Povilas; Franchi, Dorella; Fischerova, Daniela; Savelli, Luca; Van Calster, Ben; Timmerman, Dirk

2017-06-02

The aim of this study was to assess and compare the performance of different ultrasound-based International Ovarian Tumor Analysis (IOTA) strategies and subjective assessment for the diagnosis of early stage ovarian malignancy. This is a secondary analysis of a prospective multicenter cross-sectional diagnostic accuracy study that included 1653 patients recruited at 18 centers from 2009 to 2012. All patients underwent standardized transvaginal ultrasonography by experienced ultrasound investigators. We assessed test performance of the IOTA Simple Rules (SRs), Simple Rules Risk (SRR), the Assessment of Different NEoplasias in the adneXa (ADNEX) model and subjective assessment to discriminate between stage I-II ovarian cancer and benign disease. Reference standard was histology after surgery. 230 (13.9%) patients proved to have stage I-II primary invasive ovarian malignancy, and 1423 (86.1%) had benign disease. Sensitivity and specificity with respect to malignancy (95% confidence intervals) of the original SRs (classifying all inconclusive cases as malignant) were 94.3% (90.6% to 96.7%) and 73.4% (71.0% to 75.6%). Subjective assessment had a sensitivity and specificity of 90.0% (85.4% to 93.2%) and 86.7% (84.9% to 88.4%), respectively. The areas under the receiver operator characteristic curves of SRR and ADNEX were 0.917 (0.902 to 0.933) and 0.905 (0.920 to 0.934), respectively. At a 1% risk cut-off, sensitivity and specificity for SRR were 100% (98.4% to 100%) and 38.0% (35.5% to 40.6%), and for ADNEX were 100% (98.4% to 100%) and 19.4% (17.4% to 21.5%). At a 30% risk cut-off, sensitivity and specificity for SRR were 88.3% (83.5% to 91.8%) and 81.1% (79% to 83%), and for ADNEX were 84.5% (80.5% to 89.6%) and 84.5% (82.6% to 86.3%). This study shows that all three IOTA strategies have good ability to discriminate between stage I-II ovarian malignancy and benign disease.

Asymmetric exponential amplification reaction on a toehold/biotin featured template: an ultrasensitive and specific strategy for isothermal microRNAs analysis

PubMed Central

Chen, Jun; Zhou, Xueqing; Ma, Yingjun; Lin, Xiulian; Dai, Zong; Zou, Xiaoyong

2016-01-01

The sensitive and specific analysis of microRNAs (miRNAs) without using a thermal cycler instrument is significant and would greatly facilitate biological research and disease diagnostics. Although exponential amplification reaction (EXPAR) is the most attractive strategy for the isothermal analysis of miRNAs, its intrinsic limitations of detection efficiency and inevitable non-specific amplification critically restrict its use in analytical sensitivity and specificity. Here, we present a novel asymmetric EXPAR based on a new biotin/toehold featured template. A biotin tag was used to reduce the melting temperature of the primer/template duplex at the 5′ terminus of the template, and a toehold exchange structure acted as a filter to suppress the non-specific trigger of EXPAR. The asymmetric EXPAR exhibited great improvements in amplification efficiency and specificity as well as a dramatic extension of dynamic range. The limit of detection for the let-7a analysis was decreased to 6.02 copies (0.01 zmol), and the dynamic range was extended to 10 orders of magnitude. The strategy enabled the sensitive and accurate analysis of let-7a miRNA in human cancer tissues with clearly better precision than both standard EXPAR and RT-qPCR. Asymmetric EXPAR is expected to have an important impact on the development of simple and rapid molecular diagnostic applications for short oligonucleotides. PMID:27257058

Diagnosis of schistosomiasis japonica with interfacial co-assembly-based multi-channel electrochemical immunosensor arrays

NASA Astrophysics Data System (ADS)

Deng, Wangping; Xu, Bin; Hu, Haiyan; Li, Jianyong; Hu, Wei; Song, Shiping; Feng, Zheng; Fan, Chunhai

2013-05-01

Schistosomiasis control remains to be an important and challenging task in the world. However, lack of quick, simple, sensitive and specific sero-diagnostic test is still a hurdle in the control practice. The commonly employed enzyme-linked immuno-sorbent assay (ELISA) relies on the native soluble egg antigen (SEA) that is limited in supply. Here we developed an electrochemical immunosensor array (ECISA) assay with an interfacial co-assembly strategy. A recombinant Schistosoma japonicum (Sj) calcium-binding protein (SjE16) was used as a principal antigen, while the SEA as a minor, co-assembling agent, with a ratio of 8:1 (SjE16: SEA, Sj16EA), which was co-immobilized on a disposable 16-channel screen-printed carbon electrode array. A portable electrochemical detector was employed to detect antibodies in serum samples. The sensitivity of ECISA reached 100% with minimal cross-reactions. Therefore, we have demonstrated that this rapid, sensitive and specific ECISA technique has the potential to perform large-scale on-site screening of Sj infection.

Rapid and sensitive detection of Citrus Bacterial Canker by loop-mediated isothermal amplification combined with simple visual evaluation methods

PubMed Central

2010-01-01

Background Citrus Bacterial Canker (CBC) is a major, highly contagious disease of citrus plants present in many countries in Asia, Africa and America, but not in the Mediterranean area. There are three types of Citrus Bacterial Canker, named A, B, and C that have different genotypes and posses variation in host range within citrus species. The causative agent for type A CBC is Xanthomonas citri subsp. citri, while Xanthomonas fuscans subsp. aurantifolii, strain B causes type B CBC and Xanthomonas fuscans subsp. aurantifolii strain C causes CBC type C. The early and accurate identification of those bacteria is essential for the protection of the citrus industry. Detection methods based on bacterial isolation, antibodies or polymerase chain reaction (PCR) have been developed previously; however, these approaches may be time consuming, laborious and, in the case of PCR, it requires expensive laboratory equipment. Loop-mediated isothermal amplification (LAMP), which is a novel isothermal DNA amplification technique, is sensitive, specific, fast and requires no specialized laboratory equipment. Results A loop-mediated isothermal amplification assay for the diagnosis of Citrus Bacterial Canker (CBC-LAMP) was developed and evaluated. DNA samples were obtained from infected plants or cultured bacteria. A typical ladder-like pattern on gel electrophoresis was observed in all positive samples in contrast to the negative controls. In addition, amplification products were detected by visual inspection using SYBRGreen and using a lateral flow dipstick, eliminating the need for gel electrophoresis. The sensitivity and specificity of the assay were evaluated in different conditions and using several sample sources which included purified DNA, bacterium culture and infected plant tissue. The sensitivity of the CBC-LAMP was 10 fg of pure Xcc DNA, 5 CFU in culture samples and 18 CFU in samples of infected plant tissue. No cross reaction was observed with DNA of other phytopathogenic bacteria. The assay was capable of detecting CBC-causing strains from several geographical origins and pathotypes. Conclusions The CBC-LAMP technique is a simple, fast, sensitive and specific method for the diagnosis of Citrus Bacterial Canker. This method can be useful in the phytosanitary programs of the citrus industry worldwide. PMID:20565886

Sensitive and rapid detection of Chlamydia trachomatis by recombinase polymerase amplification directly from urine samples.

PubMed

Krõlov, Katrin; Frolova, Jekaterina; Tudoran, Oana; Suhorutsenko, Julia; Lehto, Taavi; Sibul, Hiljar; Mäger, Imre; Laanpere, Made; Tulp, Indrek; Langel, Ülo

2014-01-01

Chlamydia trachomatis is the most common sexually transmitted human pathogen. Infection results in minimal to no symptoms in approximately two-thirds of women and therefore often goes undiagnosed. C. trachomatis infections are a major public health concern because of the potential severe long-term consequences, including an increased risk of ectopic pregnancy, chronic pelvic pain, and infertility. To date, several point-of-care tests have been developed for C. trachomatis diagnostics. Although many of them are fast and specific, they lack the required sensitivity for large-scale application. We describe a rapid and sensitive form of detection directly from urine samples. The assay uses recombinase polymerase amplification and has a minimum detection limit of 5 to 12 pathogens per test. Furthermore, it enables detection within 20 minutes directly from urine samples without DNA purification before the amplification reaction. Initial analysis of the assay from clinical patient samples had a specificity of 100% (95% CI, 92%-100%) and a sensitivity of 83% (95% CI, 51%-97%). The whole procedure is fairly simple and does not require specific machinery, making it potentially applicable in point-of-care settings. Copyright © 2014 American Society for Investigative Pathology and the Association for Molecular Pathology. Published by Elsevier Inc. All rights reserved.

Graphene-interfaced electrical biosensor for label-free and sensitive detection of foodborne pathogenic E. coli O157:H7.

PubMed

Pandey, Ashish; Gurbuz, Yasar; Ozguz, Volkan; Niazi, Javed H; Qureshi, Anjum

2017-05-15

E. coli O157:H7 is an enterohemorrhagic bacteria responsible for serious foodborne outbreaks that causes diarrhoea, fever and vomiting in humans. Recent foodborne E. coli outbreaks has left a serious concern to public health. Therefore, there is an increasing demand for a simple, rapid and sensitive method for pathogen detection in contaminated foods. In this study, we developed a label-free electrical biosensor interfaced with graphene for sensitive detection of pathogenic bacteria. This biosensor was fabricated by interfacing graphene with interdigitated microelectrodes of capacitors that were biofunctionalized with E. coli O157:H7 specific antibodies for sensitive pathogenic bacteria detection. Here, graphene nanostructures on the sensor surface provided superior chemical properties such as high carrier mobility and biocompatibility with antibodies and bacteria. The sensors transduced the signal based on changes in dielectric properties (capacitance) through (i) polarization of captured cell-surface charges, (ii) cells' internal bioactivity, (iii) cell-wall's electronegativity or dipole moment and their relaxation and (iv) charge carrier mobility of graphene that modulated the electrical properties once the pathogenic E. coli O157:H7 captured on the sensor surface. Sensitive capacitance changes thus observed with graphene based capacitors were specific to E. coli O157:H7 strain with a sensitivity as low as 10-100 cells/ml. The proposed graphene based electrical biosensor provided advantages of speed, sensitivity, specificity and in-situ bacterial detection with no chemical mediators, represents a versatile approach for detection of a wide variety of other pathogens. Copyright © 2016 Elsevier B.V. All rights reserved.

Simultaneous Determination of Potassium Clavulanate and Amoxicillin Trihydrate in Bulk, Pharmaceutical Formulations and in Human Urine Samples by UV Spectrophotometry

PubMed Central

Gujral, Rajinder Singh; Haque, Sk Manirul

2010-01-01

A simple and sensitive UV spectrophotometric method was developed and validated for the simultaneous determination of Potassium Clavulanate (PC) and Amoxicillin Trihydrate (AT) in bulk, pharmaceutical formulations and in human urine samples. The method was linear in the range of 0.2–8.5 μg/ml for PC and 6.4–33.6 μg/ml for AT. The absorbance was measured at 205 and 271 nm for PC and AT respectively. The method was validated with respect to accuracy, precision, specificity, ruggedness, robustness, limit of detection and limit of quantitation. This method was used successfully for the quality assessment of four PC and AT drug products and in human urine samples with good precision and accuracy. This is found to be simple, specific, precise, accurate, reproducible and low cost UV Spectrophotometric method. PMID:23675211

The cut-off values of anthropometric variables for predicting mild cognitive impairment in Malaysian older adults: a large population based cross-sectional study

PubMed Central

Won, Huiloo; Abdul, Manaf Zahara; Mat Ludin, Arimi Fitri; Omar, Mohd Azahadi; Razali, Rosdinom; Shahar, Suzana

2017-01-01

Purpose Older adults are at risk of mild cognitive impairment (MCI), and simple anthropometric measurements can be used to screen for this condition. Thus, the aim of this study was to explore the cut-off values of body mass index (BMI) and waist circumference (WC) for predicting the risk of MCI in older Malaysian adults. Methods A total of 2,240 Malaysian older adults aged ≥60 years were recruited using multistage random sampling in a population based cross-sectional study. Receiver operating characteristic (ROC) curve was used to determine the cut-off values of BMI and WC with optimum sensitivity and specificity for the detection of MCI. Age, gender, years of education, smoking habit, alcohol consumption, depression, and medical conditions were used as confounding factors in this analysis. Results A BMI cut-off value of 26 kg/m2 (area under the receiver operating characteristic curve [AUC] 0.725; sensitivity 90.5%; specificity 38.8%) was appropriate in identifying the risk of getting MCI in both men and women. The optimum WC cut-offs for likelihood of MCI were 90 cm (AUC 0.745; sensitivity 78.0%; specificity 59.8%) for men and 82 cm (AUC 0.714; sensitivity 84.3%; specificity 49.7%) for women. The optimum calf circumference (CC) cut-off values for identifying MCI were 29 cm (AUC 0.731; sensitivity 72.6%; specificity 61.1%) for men and 26 cm (AUC 0.598; sensitivity 79.1%; specificity 45.3%) for women. Conclusion The cut-off values could be advocated and used as part of the screening of MCI among older Malaysian adults. There is a need to further determine the predictive values of these cut-off points on outcomes through longitudinal study design. PMID:28223785

A simple, fast and sensitive screening LC-ESI-MS/MS method for antibiotics in fish.

PubMed

Guidi, Letícia Rocha; Santos, Flávio Alves; Ribeiro, Ana Cláudia S R; Fernandes, Christian; Silva, Luiza H M; Gloria, Maria Beatriz A

2017-01-15

The objective of this study was to develop and validate a fast, sensitive and simple liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS/MS) method for the screening of six classes of antibiotics (aminoglycosides, beta-lactams, macrolides, quinolones, sulfonamides and tetracyclines) in fish. Samples were extracted with trichloroacetic acid. LC separation was achieved on a Zorbax Eclipse XDB C18 column and gradient elution using 0.1% heptafluorobutyric acid in water and acetonitrile as mobile phase. Analysis was carried out in multiple reaction monitoring mode via electrospray interface operated in the positive ionization mode, with sulfaphenazole as internal standard. The method was suitable for routine screening purposes of 40 antibiotics, according to EC Guidelines for the Validation of Screening Methods for Residues of Veterinary Medicines, taking into consideration threshold value, cut-off factor, detection capability, limit of detection, sensitivity and specificity. Real fish samples (n=193) from aquaculture were analyzed and 15% were positive for enrofloxacin (quinolone), one of them at a higher concentration than the level of interest (50µgkg -1 ), suggesting possible contamination or illegal use of that antibiotic. Copyright © 2016 Elsevier B.V. All rights reserved.

The Role of Nanoparticle Design in Determining Analytical Performance of Lateral Flow Immunoassays.

PubMed

Zhan, Li; Guo, Shuang-Zhuang; Song, Fayi; Gong, Yan; Xu, Feng; Boulware, David R; McAlpine, Michael C; Chan, Warren C W; Bischof, John C

2017-12-13

Rapid, simple, and cost-effective diagnostics are needed to improve healthcare at the point of care (POC). However, the most widely used POC diagnostic, the lateral flow immunoassay (LFA), is ∼1000-times less sensitive and has a smaller analytical range than laboratory tests, requiring a confirmatory test to establish truly negative results. Here, a rational and systematic strategy is used to design the LFA contrast label (i.e., gold nanoparticles) to improve the analytical sensitivity, analytical detection range, and antigen quantification of LFAs. Specifically, we discovered that the size (30, 60, or 100 nm) of the gold nanoparticles is a main contributor to the LFA analytical performance through both the degree of receptor interaction and the ultimate visual or thermal contrast signals. Using the optimal LFA design, we demonstrated the ability to improve the analytical sensitivity by 256-fold and expand the analytical detection range from 3 log 10 to 6 log 10 for diagnosing patients with inflammatory conditions by measuring C-reactive protein. This work demonstrates that, with appropriate design of the contrast label, a simple and commonly used diagnostic technology can compete with more expensive state-of-the-art laboratory tests.

Preoperative identification of a suspicious adnexal mass: a systematic review and meta-analysis.

PubMed

Dodge, Jason E; Covens, Allan L; Lacchetti, Christina; Elit, Laurie M; Le, Tien; Devries-Aboud, Michaela; Fung-Kee-Fung, Michael

2012-07-01

To systematically review the existing literature in order to determine the optimal strategy for preoperative identification of the adnexal mass suspicious for ovarian cancer. A review of all systematic reviews and guidelines published between 1999 and 2009 was conducted as a first step. After the identification of a 2004 AHRQ systematic review on the topic, searches of MEDLINE for studies published since 2004 was also conducted to update and supplement the evidentiary base. A bivariate, random-effects meta-regression model was used to produce summary estimates of sensitivity and specificity and to plot summary ROC curves with 95% confidence regions. Four meta-analyses and 53 primary studies were included in this review. The diagnostic performance of each technology was compared and contrasted based on the summary data on sensitivity and specificity obtained from the meta-analysis. Results suggest that 3D ultrasonography has both a higher sensitivity and specificity when compared to 2D ultrasound. Established morphological scoring systems also performed with respectable sensitivity and specificity, each with equivalent diagnostic competence. Explicit scoring systems did not perform as well as other diagnostic testing methods. Assessment of an adnexal mass by colour Doppler technology was neither as sensitive nor as specific as simple ultrasonography. Of the three imaging modalities considered, MRI appeared to perform the best, although results were not statistically different from CT. PET did not perform as well as either MRI or CT. The measurement of the CA-125 tumour marker appears to be less reliable than do other available assessment methods. The best available evidence was collected and included in this rigorous systematic review and meta-analysis. The abundant evidentiary base provided the context and direction for the diagnosis of early-staged ovarian cancer. Copyright © 2012 Elsevier Inc. All rights reserved.

PCR method based on the ogdH gene for the detection of Salmonella spp. from chicken meat samples.

PubMed

Jin, Un-Ho; Cho, Sung-Hak; Kim, Min-Gon; Ha, Sang-Do; Kim, Keun-Sung; Lee, Kyu-Ho; Kim, Kwang-Yup; Chung, Duck Hwa; Lee, Young-Choon; Kim, Cheorl-Ho

2004-09-01

In a previous paper, the ogdH gene that encodes 2-oxoglutarate dehydrogenase was isolated from Salmonella typhimurium. The catalytic N-terminal region in the enzyme was found to be very specific for the Salmonella species. Therefore, the aim of the present study was to detect S. typhimurium in food sources using primers designed for OGDH-1 and OGDH-2 which were based on the salmonella-specific region of the ogdH gene. A simple polymerase chain reaction (PCR) detection method was developed to detect low numbers of S. typhimurium in a chicken meat microbial consortium. Using the ogdH-specific primers under stringent amplification conditions and for gene probe analysis, fewer than 100 colony-forming units (CFUs) were detectable when pure cultures were employed. When the PCR assay was run on S. typhimurium-contaminated meat contents, only the positive meat samples containing as few as 200 CFUs reacted to the assay. The method employed for sample processing is simple and it was determined to provide a sensitive means of detecting trace amounts of S. typhimurium-specific sequences in the presence of mixed meat microbial populations. When compared with six representative intestinal gram-negative bacterial strains in foods, including Vibrio parahaemolyticus, V. vulnificus, Enterobacter cloacae, E. coli O157:H7, Pseudomonas aeruginosa, and Proteus sp., S. typhimurium had a unique and distinct PCR product (796 bp). In conclusion, the two OGDH primers were found to be rapid and sensitive detectors of Salmonella spp for the PCR method. Copyright 2004 The Microbiological Society of Korea

Utilizing a CdTe quantum dots-enzyme hybrid system for the determination of both phenolic compounds and hydrogen peroxide.

PubMed

Yuan, Jipei; Guo, Weiwei; Wang, Erkang

2008-02-15

In this paper, we attempt to construct a simple and sensitive detection method for both phenolic compounds and hydrogen peroxide, with the successful combination of the unique property of quantum dots and the specificity of enzymatic reactions. In the presence of H2O2 and horseradish peroxidase, phenolic compounds can quench quantum dots' photoluminescence efficiently, and the extent of quenching is severalfold to more than 100-fold increase. Quinone intermediates produced from the enzymatic catalyzed oxidation of phenolic compounds were believed to play the main role in the photoluminescence quenching. Using a quantum dots-enzyme system, the detection limits for phenolic compounds and hydrogen peroxide were detected to be approximately 10(-7) mol L(-1). The coupling of efficient quenching of quantum dot photoluminescence by quinone and the effective enzymatic reactions make this a simple and sensitive method for phenolic compound detection and great potential in the development of H2O2 biosensors for various analytes.

Rapid and sensitive detection of Yersinia pestis using amplification of plague diagnostic bacteriophages monitored by real-time PCR.

PubMed

Sergueev, Kirill V; He, Yunxiu; Borschel, Richard H; Nikolich, Mikeljon P; Filippov, Andrey A

2010-06-28

Yersinia pestis, the agent of plague, has caused many millions of human deaths and still poses a serious threat to global public health. Timely and reliable detection of such a dangerous pathogen is of critical importance. Lysis by specific bacteriophages remains an essential method of Y. pestis detection and plague diagnostics. The objective of this work was to develop an alternative to conventional phage lysis tests--a rapid and highly sensitive method of indirect detection of live Y. pestis cells based on quantitative real-time PCR (qPCR) monitoring of amplification of reporter Y. pestis-specific bacteriophages. Plague diagnostic phages phiA1122 and L-413C were shown to be highly effective diagnostic tools for the detection and identification of Y. pestis by using qPCR with primers specific for phage DNA. The template DNA extraction step that usually precedes qPCR was omitted. phiA1122-specific qPCR enabled the detection of an initial bacterial concentration of 10(3) CFU/ml (equivalent to as few as one Y. pestis cell per 1-microl sample) in four hours. L-413C-mediated detection of Y. pestis was less sensitive (up to 100 bacteria per sample) but more specific, and thus we propose parallel qPCR for the two phages as a rapid and reliable method of Y. pestis identification. Importantly, phiA1122 propagated in simulated clinical blood specimens containing EDTA and its titer rise was detected by both a standard plating test and qPCR. Thus, we developed a novel assay for detection and identification of Y. pestis using amplification of specific phages monitored by qPCR. The method is simple, rapid, highly sensitive, and specific and allows the detection of only live bacteria.

Bridging the gap between sample collection and laboratory analysis: using dried blood spots to identify human exposure to chemical agents

NASA Astrophysics Data System (ADS)

Hamelin, Elizabeth I.; Blake, Thomas A.; Perez, Jonas W.; Crow, Brian S.; Shaner, Rebecca L.; Coleman, Rebecca M.; Johnson, Rudolph C.

2016-05-01

Public health response to large scale chemical emergencies presents logistical challenges for sample collection, transport, and analysis. Diagnostic methods used to identify and determine exposure to chemical warfare agents, toxins, and poisons traditionally involve blood collection by phlebotomists, cold transport of biomedical samples, and costly sample preparation techniques. Use of dried blood spots, which consist of dried blood on an FDA-approved substrate, can increase analyte stability, decrease infection hazard for those handling samples, greatly reduce the cost of shipping/storing samples by removing the need for refrigeration and cold chain transportation, and be self-prepared by potentially exposed individuals using a simple finger prick and blood spot compatible paper. Our laboratory has developed clinical assays to detect human exposures to nerve agents through the analysis of specific protein adducts and metabolites, for which a simple extraction from a dried blood spot is sufficient for removing matrix interferents and attaining sensitivities on par with traditional sampling methods. The use of dried blood spots can bridge the gap between the laboratory and the field allowing for large scale sample collection with minimal impact on hospital resources while maintaining sensitivity, specificity, traceability, and quality requirements for both clinical and forensic applications.

Simple questionnaire and urine reagent strips compared to microscopy for the diagnosis of Schistosoma haematobium in a community in northern Ghana.

PubMed

Bogoch, Isaac I; Andrews, Jason R; Dadzie Ephraim, Richard K; Utzinger, Jürg

2012-10-01

To evaluate the utility of a simple questionnaire and urine reagent strip testing for the rapid diagnosis of Schistosoma haematobium in rural northern Ghana. Cross-sectional parasitological and questionnaire survey in a community in northern Ghana. Participants provided two urine specimens that were examined under a microscope using a centrifugation method. The first urine sample was additionally subjected to reagent strip testing. A short questionnaire was administered to all participants. Microscopy of urine samples obtained from 208 individuals aged 1-77 years revealed an S. haematobium prevalence of 6.8%. The presence of any blood or protein on a urine reagent strip was 100% and 42% sensitive, and 93% and 80% specific for S. haematobium diagnosis. Questionnaires were completed by 198 individuals. Self-reported haematuria showed a sensitivity of 53% and a specificity of 85%. A dichotomous two-question panel was helpful in S. haematobium diagnosis, with working and playing near the river significantly associated with S. haematobium infection (P < 0.001). The use of urine reagent strips, coupled with questions pertaining to water contact patterns, might be considered for point-of-contact diagnosis of S. haematobium where microscopy is unavailable. © 2012 Blackwell Publishing Ltd.

An original approach was used to better evaluate the capacity of a prognostic marker using published survival curves.

PubMed

Dantan, Etienne; Combescure, Christophe; Lorent, Marine; Ashton-Chess, Joanna; Daguin, Pascal; Classe, Jean-Marc; Giral, Magali; Foucher, Yohann

2014-04-01

Predicting chronic disease evolution from a prognostic marker is a key field of research in clinical epidemiology. However, the prognostic capacity of a marker is not systematically evaluated using the appropriate methodology. We proposed the use of simple equations to calculate time-dependent sensitivity and specificity based on published survival curves and other time-dependent indicators as predictive values, likelihood ratios, and posttest probability ratios to reappraise prognostic marker accuracy. The methodology is illustrated by back calculating time-dependent indicators from published articles presenting a marker as highly correlated with the time to event, concluding on the high prognostic capacity of the marker, and presenting the Kaplan-Meier survival curves. The tools necessary to run these direct and simple computations are available online at http://www.divat.fr/en/online-calculators/evalbiom. Our examples illustrate that published conclusions about prognostic marker accuracy may be overoptimistic, thus giving potential for major mistakes in therapeutic decisions. Our approach should help readers better evaluate clinical articles reporting on prognostic markers. Time-dependent sensitivity and specificity inform on the inherent prognostic capacity of a marker for a defined prognostic time. Time-dependent predictive values, likelihood ratios, and posttest probability ratios may additionally contribute to interpret the marker's prognostic capacity. Copyright © 2014 Elsevier Inc. All rights reserved.

A Simple PCR Method for Rapid Genotype Analysis of Mycobacterium ulcerans

PubMed Central

Stinear, Timothy; Davies, John K.; Jenkin, Grant A.; Portaels, Françoise; Ross, Bruce C.; OppEdIsano, Frances; Purcell, Maria; Hayman, John A.; Johnson, Paul D. R.

2000-01-01

Two high-copy-number insertion sequences, IS2404 and IS2606, were recently identified in Mycobacterium ulcerans and were shown by Southern hybridization to possess restriction fragment length polymorphism between strains from different geographic origins. We have designed a simple genotyping method that captures these differences by PCR amplification of the region between adjacent copies of IS2404 and IS2606. We have called this system 2426 PCR. The method is rapid, reproducible, sensitive, and specific for M. ulcerans, and it has confirmed previous studies suggesting a clonal population structure of M. ulcerans within a geographic region. M. ulcerans isolates from Australia, Papua New Guinea, Malaysia, Surinam, Mexico, Japan, China, and several countries in Africa were easily differentiated based on an array of 4 to 14 PCR products ranging in size from 200 to 900 bp. Numerical analysis of the banding patterns suggested a close evolutionary link between M. ulcerans isolates from Africa and southeast Asia. The application of 2426 PCR to total DNA, extracted directly from M. ulcerans-infected tissue specimens without culture, demonstrated the sensitivity and specificity of this method and confirmed for the first time that both animal and human isolates from areas of endemicity in southeast Australia have the same genotype. PMID:10747130

Assessment of insulin sensitivity from measurements in fasting state and during an oral glucose tolerance test in obese children.

PubMed

Atabek, Mehmet Emre; Pirgon, Ozgur

2007-02-01

Few previous studies have examined the validity of the fasting glucose-to-insulin ratio (FGIR), homeostasis model assessment of insulin resistance (HOMA-IR) and quantitative insulin-sensitivity check index (QUICKI) in pediatric populations. To compare simple indices of insulin resistance calculated from fasting glucose and insulin levels with insulin sensitivity indices (area under the response curve [AUCinsulin], insulin sensitivity index [ISI-compositeL) determined by oral glucose tolerance testing (OGTT) in obese children. One hundred and forty-eight obese children and adolescents (86 girls and 62 boys, mean age: 10.86 +/- 3.08 years, mean body mass index (BMI): 27.7 +/- 4.2) participated in the study. OGTT was performed in all participants. After glucose and insulin measurements from OGTT, the children were divided into two groups according to the presence or absence of insulin resistance. Insulin sensitivity indices obtained from the OGTT were compared between the groups. The total plasma glucose response and insulin secretion were evaluated from the AUC estimated by the trapezoid rule. Cut-off points, and sensitivity and specificity calculations were based on insulin resistance with receiver operating characteristic curve (ROC) analysis. The prevalence of insulin resistance, glucose intolerance and dyslipidemia was 37.1%, 24.3% and 54% in obese children, respectively. The groups consisted of 93 children without insulin resistance (54 girls and 39 boys; mean age: 10.5 +/- 3.3 years; mean BMI: 27.0 +/- 4.2) and 55 children with insulin resistance (32 girls and 23 boys; mean age: 11.4 +/- 2.5 years; mean BMI: 27.9 +/- 3.9). There were significant differences in mean FGIR (10.0 +/- 7.2 vs 5.6 +/- 2.8, p < 0.001), HOMA-IR (3.2 +/- 2.3 vs 4.9 +/- 2.3, p < 0.001) and QUICKI (0.33 +/- 0.03 vs 0.30 +/- 0.02, p < 0.001) between the groups. The cut-off points for diagnosis of insulin resistance were < 5.6 for FGIR (sensitivity 61.8, specificity 76.3), > 2.7 for HOMA-IR (sensitivity 80, specificity 59.1), and < 0.328 for QUICKI (sensitivity 80, specificity 60.2). Indices derived from fasting samples for diagnosis of insulin sensitivity are reliable criteria in obese children and adolescents. HOMA-IR and QUICKI appeared to have similar sensitivity and specificity and to have higher sensitivity than FGIR.

A rapid and sensitive LC-MS/MS method for the determination of Pulsatilla saponin D in rat plasma and its application in a rat pharmacokinetic and bioavailability study.

PubMed

Ouyang, Hui; Guo, Yicheng; He, Mingzhen; Zhang, Jinlian; Huang, Xiaofang; Zhou, Xin; Jiang, Hongliang; Feng, Yulin; Yang, Shilin

2015-03-01

A simple, sensitive and specific liquid chromatography-tandem mass spectrometry method was developed and validated for the determination of Pulsatilla saponin D, a potential antitumor constituent isolated from Pulsatilla chinensis in rat plasma. Rat plasma samples were pretreated by protein precipitation with methanol. The method validation was performed in accordance with US Food and Drug Administration guidelines and the results met the acceptance criteria. The method was successfully applied to assess the pharmacokinetics and oral bioavailability of Pulsatilla saponin D in rats. Copyright © 2014 John Wiley & Sons, Ltd.

Polymeric anticancer drugs with pH-controlled activation.

PubMed

Ulbrich, Karel; Subr, Vladimír

2004-04-23

Use of macromolecular water-soluble carriers of anti-cancer drugs represents a promising approach to cancer therapy. Release of drugs from the carrier system is a prerequisite for therapeutic activity of most macromolecular anti-cancer conjugates. Incorporation of acid-sensitive spacers between the drug and carrier enables release of an active drug from the carrier in a tumor tissue, either in slightly acidic extracellular fluids or, after endocytosis, in endosomes or lysosomes of cancer cells. This paper reviews advances in development and study of properties of various acid-sensitive macromolecular drug delivery systems, starting from simple polymer-drug conjugates to ending with site-specific antibody-targeted polymer-drug conjugates.

Rapid Diagnosis of Tuberculosis from Analysis of Urine Volatile Organic Compounds

PubMed Central

Lim, Sung H.; Martino, Raymond; Anikst, Victoria; Xu, Zeyu; Mix, Samantha; Benjamin, Robert; Schub, Herbert; Eiden, Michael; Rhodes, Paul A.; Banaei, Niaz

2017-01-01

The World Health Organization has called for simple, sensitive, and non-sputum diagnostics for tuberculosis. We report development of a urine tuberculosis test using a colorimetric sensor array (CSA). The sensor comprised of 73 different indicators captures high-dimensional, spatiotemporal signatures of volatile chemicals emitted by human urine samples. The sensor responses to 63 urine samples collected from 22 tuberculosis cases and 41 symptomatic controls were measured under five different urine test conditions. Basified testing condition yielded the best accuracy with 85.5% sensitivity and 79.5% specificity. The CSA urine assay offers desired features needed for tuberculosis diagnosis in endemic settings. PMID:29057329

[Evaluation of ICT malaria immunochromatographic Binax NOW ICT P.f/P.v test for rapid diagnosis of malaria in a Colombian endemic area].

PubMed

Pabón, Adriana; Alvarez, Gonzalo; Yánez, Jorge; Céspedes, Carlos; Rodríguez, Yensa; Restrepo, Angela; Blair, Silvia

2007-06-01

One of the strategies to reduce malarial morbidity and mortality is to make an early diagnosis, using simple rapid tests which are highly sensitive and specific. Furthermore, the tests must be easy to perform and understand by local people in such a way that a suitable and prompt antimalarial treatment is guaranteed. The sensitivity and specificity was determined for the immuno-chromographic malaria dipstick (ICT Pf/Pv) test for the rapid diagnosis of malaria in Turbo, Antioquia. The sample consisted of 171 patients distributed into two groups: the first group was 118 patients with acute febrile syndrome compatible with malaria to which ICT Pf/Pv and thick smears were applied simultaneously; a second group was 53 patients with positive diagnosis by thick smear, with follow-up on the 4th and 7th days after beginning treatment. Sensitivity and specificity of the ICT Pf/Pv test for Plasmodium falciparum infections were 54.2% (95%CI: 52.0-53.4%) and 93.6% (95%CI: 93.1-94.2%), respectively. In addition, for Plasmodium vivax the sensitivity and specificity were 80% (95%CI: 77.9-82.1%) and 100% (95%CI: 99.5-100%); there was a 21.4% loss of sensitivity for P. falciparum 21.4% and a 33% loss for P. vivax malaria with parasitaemias under 500 parasites/ul. For the confirmatory test, ICT Pf/Pv showed a global sensitivity of 71.6% with 20.7% false positive and 5.6% false negative results. During follow-up, ICT showed 36% and 34% false positive results for day 4 and 7, respectively. The ICT Pf/Pv test has a poor sensitivity for P. falciparum malaria and its capacity to detect parasitemias under 500 parasites/ul is minimal. As a confirmatory test, the ICT Pf/Pv has a good sensitivity for P. falciparum. Its use for patient follow-up is not recommended.

A new responder criterion (relative effect per patient (REPP) > 0.2) externally validated in a large total hip replacement multicenter cohort (EUROHIP).

PubMed

Huber, J; Hüsler, J; Dieppe, P; Günther, K P; Dreinhöfer, K; Judge, A

2016-03-01

To validate a new method to identify responders (relative effect per patient (REPP) >0.2) using the OMERACT-OARSI criteria as gold standard in a large multicentre sample. The REPP ([score before - after treatment]/score before treatment) was calculated for 845 patients of a large multicenter European cohort study for THR. The patients with a REPP >0.2 were defined as responders. The responder rate was compared to the gold standard (OMERACT-OARSI criteria) using receiver operator characteristic (ROC) curve analysis for sensitivity, specificity and percentage of appropriately classified patients. With the criterion REPP>0.2 85.4% of the patients were classified as responders, applying the OARSI-OMERACT criteria 85.7%. The new method had 98.8% sensitivity, 94.2% specificity and 98.1% of the patients were correctly classified compared to the gold standard. The external validation showed a high sensitivity and also specificity of a new criterion to identify a responder compared to the gold standard method. It is simple and has no uncertainties due to a single classification criterion. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

Comparison of the efficacy of three PubMed search filters in finding randomized controlled trials to answer clinical questions.

PubMed

Yousefi-Nooraie, Reza; Irani, Shirin; Mortaz-Hedjri, Soroush; Shakiba, Behnam

2013-10-01

The aim of this study was to compare the performance of three search methods in the retrieval of relevant clinical trials from PubMed to answer specific clinical questions. Included studies of a sample of 100 Cochrane reviews which recorded in PubMed were considered as the reference standard. The search queries were formulated based on the systematic review titles. Precision, recall and number of retrieved records for limiting the results to clinical trial publication type, and using sensitive and specific clinical queries filters were compared. The number of keywords, presence of specific names of intervention and syndrome in the search keywords were used in a model to predict the recalls and precisions. The Clinical queries-sensitive search strategy retrieved the largest number of records (33) and had the highest recall (41.6%) and lowest precision (4.8%). The presence of specific intervention name was the only significant predictor of all recalls and precisions (P = 0.016). The recall and precision of combination of simple clinical search queries and methodological search filters to find clinical trials in various subjects were considerably low. The limit field strategy yielded in higher precision and fewer retrieved records and approximately similar recall, compared with the clinical queries-sensitive strategy. Presence of specific intervention name in the search keywords increased both recall and precision. © 2010 John Wiley & Sons Ltd.

Detection of early stage prostate cancer by using a simple carbon nanotube@paper biosensor.

PubMed

Ji, Sungkyung; Lee, Myeongsoon; Kim, Don

2018-04-15

This study is an investigation for an inexpensive, simple and sensitive biosensor to detect prostate cancer using bioactivated-multi wall carbon nanotubes (MWCNTs, diameter of 20nm, length of 5µm) and a micro-pore filter paper (pore size of 0.45µm). For the immunoassay of prostate specific antigen (PSA), which is a biomarker of prostate cancer, MWCNTs were activated with PSA antibody (monoclonal antibody of the prostate specific antigen) by using N-(3-dimethylaminopropyl)-N'-ethylcarbodiimide hydrochloride (EDC) and N-hydroxysulfosuccinimide sodium salt (NHSS). The activated MWCNTs were deposited on the micro-pore filter paper to use as a biosensor. The prepared biosensor can assay from 0 to 500ng/mL of PSA level within 2h with the detection limit of 1.18ng/mL by the measurement of resistance change. The resistance change was caused by site selective interaction between PSA and PSA-antigen with an inexpensive bench top digital multimeter (5 1/2 digits). The detection range and sensitivity of the prepared sensor are good enough to diagnose the early stage of prostate cancer (> 4ng/mL of PSA). This paper-based biosensor is about 20 times cheaper (fabricated biosensor price: 2.4 $) and over 10 times faster than enzyme-linked immunosorbent assay (ELISA), which is a general method for the detection of a specific protein in the modernized hospitals. Furthermore, the maximum detection limit is about 50 times higher than ELISA. Copyright © 2017 Elsevier B.V. All rights reserved.

Strategies to diagnose ovarian cancer: new evidence from phase 3 of the multicentre international IOTA study.

PubMed

Testa, A; Kaijser, J; Wynants, L; Fischerova, D; Van Holsbeke, C; Franchi, D; Savelli, L; Epstein, E; Czekierdowski, A; Guerriero, S; Fruscio, R; Leone, F P G; Vergote, I; Bourne, T; Valentin, L; Van Calster, B; Timmerman, D

2014-08-12

To compare different ultrasound-based international ovarian tumour analysis (IOTA) strategies and risk of malignancy index (RMI) for ovarian cancer diagnosis using a meta-analysis approach of centre-specific data from IOTA3. This prospective multicentre diagnostic accuracy study included 2403 patients with 1423 benign and 980 malignant adnexal masses from 2009 until 2012. All patients underwent standardised transvaginal ultrasonography. Test performance of RMI, subjective assessment (SA) of ultrasound findings, two IOTA risk models (LR1 and LR2), and strategies involving combinations of IOTA simple rules (SRs), simple descriptors (SDs) and LR2 with and without SA was estimated using a meta-analysis approach. Reference standard was histology after surgery. The areas under the receiver operator characteristic curves of LR1, LR2, SA and RMI were 0.930 (0.917-0.942), 0.918 (0.905-0.930), 0.914 (0.886-0.936) and 0.875 (0.853-0.894). Diagnostic one-step and two-step strategies using LR1, LR2, SR and SD achieved summary estimates for sensitivity 90-96%, specificity 74-79% and diagnostic odds ratio (DOR) 32.8-50.5. Adding SA when IOTA methods yielded equivocal results improved performance (DOR 57.6-75.7). Risk of Malignancy Index had sensitivity 67%, specificity 91% and DOR 17.5. This study shows all IOTA strategies had excellent diagnostic performance in comparison with RMI. The IOTA strategy chosen may be determined by clinical preference.

Can the efficiency of modified Alvarado scoring system in the diagnosis acute appendicitis be increased with tenesmus?

PubMed

Bulus, Hakan; Tas, Adnan; Morkavuk, Baris; Koklu, Seyfettin; Soy, Derya; Coskun, Ali

2013-01-01

Acute appendicitis is one of the main pathological conditions requiring emergency surgical intervention. The most widely accepted scoring system is modified Alvarado scoring system (MASS). In this study we aimed to improve the efficiency of MASS by adding a new parameter and to evaluate its efficiency in the diagnosis of acute appendicitis. This study included 158 patients who underwent acute appendectomy in Keçiören Training and Research Hospital General Surgery Department. In addition to criteria of MASS, all patients were questioned about the presence of tenesmus. The validity of MASS and MASS with additional parameter was evaluated with respect to sensitivity, specificity and positive and negative predictive values. Accuracy rates of MASS, clinical findings, ultrasonography and MASS with additional parameter in the diagnosis of acute appendicitis were 64, 76, 85 and 80 %. False positivity rates for clinical findings, MASS and MASS with additional parameter in the diagnosis of acute appendicitis were 17, 26 and 10 %, respectively. Sensitivity and specificity of clinical findings in the diagnosis of acute appendicitis were 83 and 66 %, respectively. Sensitivity and specificity of MASS in the diagnosis of acute appendicitis were 74 and 39 %, respectively, and those of MASS with additional parameter were appendicitis increased to 83 and 66 %, respectively. MASS is a simple, cheap and objective scoring system and does not require expertise. When tenesmus is added to standard MASS, rates of accuracy, sensitivity and specificity become better than those in MASS in the diagnosis of acute appendicitis.

Sensitive and specific miRNA detection method using SplintR Ligase

PubMed Central

Jin, Jingmin; Vaud, Sophie; Zhelkovsky, Alexander M.; Posfai, Janos; McReynolds, Larry A.

2016-01-01

We describe a simple, specific and sensitive microRNA (miRNA) detection method that utilizes Chlorella virus DNA ligase (SplintR® Ligase). This two-step method involves ligation of adjacent DNA oligonucleotides hybridized to a miRNA followed by real-time quantitative PCR (qPCR). SplintR Ligase is 100X faster than either T4 DNA Ligase or T4 RNA Ligase 2 for RNA splinted DNA ligation. Only a 4–6 bp overlap between a DNA probe and miRNA was required for efficient ligation by SplintR Ligase. This property allows more flexibility in designing miRNA-specific ligation probes than methods that use reverse transcriptase for cDNA synthesis of miRNA. The qPCR SplintR ligation assay is sensitive; it can detect a few thousand molecules of miR-122. For miR-122 detection the SplintR qPCR assay, using a FAM labeled double quenched DNA probe, was at least 40× more sensitive than the TaqMan assay. The SplintR method, when coupled with NextGen sequencing, allowed multiplex detection of miRNAs from brain, kidney, testis and liver. The SplintR qPCR assay is specific; individual let-7 miRNAs that differ by one nucleotide are detected. The rapid kinetics and ability to ligate DNA probes hybridized to RNA with short complementary sequences makes SplintR Ligase a useful enzyme for miRNA detection. PMID:27154271

A Comparative Study Between Smartphone-Based Microscopy and Conventional Light Microscopy in 1021 Dermatopathology Specimens.

PubMed

Jahan-Tigh, Richard R; Chinn, Garrett M; Rapini, Ronald P

2016-01-01

The incorporation of high-resolution cameras into smartphones has allowed for a variety of medical applications including the use of lens attachments that provide telescopic, macroscopic, and dermatoscopic data, but the feasibility and performance characteristics of such a platform for use in dermatopathology have not been described. To determine the diagnostic performance of a smartphone microscope compared to traditional light microscopy in dermatopathology specimens. A simple smartphone microscope constructed with a 3-mm ball lens was used to prospectively evaluate 1021 consecutive dermatopathology cases in a blinded fashion. Referred, consecutive specimens from the community were evaluated at a single university hospital. The performance characteristics of the smartphone platform were calculated by using conventional light microscopy as the gold standard. The sensitivity and specificity for the diagnosis of melanoma, nonmelanoma skin cancers, and other miscellaneous conditions by the phone microscopy platform, as compared with traditional light microscopy, were calculated. For basal cell carcinoma (n = 136), the sensitivity and specificity of smartphone microscopy were 95.6% and 98.1%, respectively. The sensitivity and specificity for squamous cell carcinoma (n = 94) were 89.4% and 97.3%, respectively. The lowest sensitivity was found in melanoma (n = 15) at 60%, although the specificity was high at 99.1%. The accuracy of diagnosis of inflammatory conditions and other neoplasms was variable. Mobile phone-based microscopy has excellent performance characteristics for the inexpensive diagnosis of nonmelanoma skin cancers in a setting where a traditional microscope is not available.

Simple Methods and Rational Design for Enhancing Aptamer Sensitivity and Specificity

PubMed Central

Kalra, Priya; Dhiman, Abhijeet; Cho, William C.; Bruno, John G.; Sharma, Tarun K.

2018-01-01

Aptamers are structured nucleic acid molecules that can bind to their targets with high affinity and specificity. However, conventional SELEX (Systematic Evolution of Ligands by EXponential enrichment) methods may not necessarily produce aptamers of desired affinity and specificity. Thus, to address these questions, this perspective is intended to suggest some approaches and tips along with novel selection methods to enhance evolution of aptamers. This perspective covers latest novel innovations as well as a broad range of well-established approaches to improve the individual binding parameters (aptamer affinity, avidity, specificity and/or selectivity) of aptamers during and/or post-SELEX. The advantages and limitations of individual aptamer selection methods and post-SELEX optimizations, along with rational approaches to overcome these limitations are elucidated in each case. Further the impact of chosen selection milieus, linker-systems, aptamer cocktails and detection modules utilized in conjunction with target-specific aptamers, on the overall assay performance are discussed in detail, each with its own advantages and limitations. The simple variations suggested are easily available for facile implementation during and/or post-SELEX to develop ultrasensitive and specific assays. Finally, success studies of established aptamer-based assays are discussed, highlighting how they utilized some of the suggested methodologies to develop commercially successful point-of-care diagnostic assays. PMID:29868605

Simple Methods and Rational Design for Enhancing Aptamer Sensitivity and Specificity.

PubMed

Kalra, Priya; Dhiman, Abhijeet; Cho, William C; Bruno, John G; Sharma, Tarun K

2018-01-01

Aptamers are structured nucleic acid molecules that can bind to their targets with high affinity and specificity. However, conventional SELEX (Systematic Evolution of Ligands by EXponential enrichment) methods may not necessarily produce aptamers of desired affinity and specificity. Thus, to address these questions, this perspective is intended to suggest some approaches and tips along with novel selection methods to enhance evolution of aptamers. This perspective covers latest novel innovations as well as a broad range of well-established approaches to improve the individual binding parameters (aptamer affinity, avidity, specificity and/or selectivity) of aptamers during and/or post-SELEX. The advantages and limitations of individual aptamer selection methods and post-SELEX optimizations, along with rational approaches to overcome these limitations are elucidated in each case. Further the impact of chosen selection milieus, linker-systems, aptamer cocktails and detection modules utilized in conjunction with target-specific aptamers, on the overall assay performance are discussed in detail, each with its own advantages and limitations. The simple variations suggested are easily available for facile implementation during and/or post-SELEX to develop ultrasensitive and specific assays. Finally, success studies of established aptamer-based assays are discussed, highlighting how they utilized some of the suggested methodologies to develop commercially successful point-of-care diagnostic assays.

A low density microarray method for the identification of human papillomavirus type 18 variants.

PubMed

Meza-Menchaca, Thuluz; Williams, John; Rodríguez-Estrada, Rocío B; García-Bravo, Aracely; Ramos-Ligonio, Ángel; López-Monteon, Aracely; Zepeda, Rossana C

2013-09-26

We describe a novel microarray based-method for the screening of oncogenic human papillomavirus 18 (HPV-18) molecular variants. Due to the fact that sequencing methodology may underestimate samples containing more than one variant we designed a specific and sensitive stacking DNA hybridization assay. This technology can be used to discriminate between three possible phylogenetic branches of HPV-18. Probes were attached covalently on glass slides and hybridized with single-stranded DNA targets. Prior to hybridization with the probes, the target strands were pre-annealed with the three auxiliary contiguous oligonucleotides flanking the target sequences. Screening HPV-18 positive cell lines and cervical samples were used to evaluate the performance of this HPV DNA microarray. Our results demonstrate that the HPV-18's variants hybridized specifically to probes, with no detection of unspecific signals. Specific probes successfully reveal detectable point mutations in these variants. The present DNA oligoarray system can be used as a reliable, sensitive and specific method for HPV-18 variant screening. Furthermore, this simple assay allows the use of inexpensive equipment, making it accessible in resource-poor settings.

A Low Density Microarray Method for the Identification of Human Papillomavirus Type 18 Variants

PubMed Central

Meza-Menchaca, Thuluz; Williams, John; Rodríguez-Estrada, Rocío B.; García-Bravo, Aracely; Ramos-Ligonio, Ángel; López-Monteon, Aracely; Zepeda, Rossana C.

2013-01-01

We describe a novel microarray based-method for the screening of oncogenic human papillomavirus 18 (HPV-18) molecular variants. Due to the fact that sequencing methodology may underestimate samples containing more than one variant we designed a specific and sensitive stacking DNA hybridization assay. This technology can be used to discriminate between three possible phylogenetic branches of HPV-18. Probes were attached covalently on glass slides and hybridized with single-stranded DNA targets. Prior to hybridization with the probes, the target strands were pre-annealed with the three auxiliary contiguous oligonucleotides flanking the target sequences. Screening HPV-18 positive cell lines and cervical samples were used to evaluate the performance of this HPV DNA microarray. Our results demonstrate that the HPV-18's variants hybridized specifically to probes, with no detection of unspecific signals. Specific probes successfully reveal detectable point mutations in these variants. The present DNA oligoarray system can be used as a reliable, sensitive and specific method for HPV-18 variant screening. Furthermore, this simple assay allows the use of inexpensive equipment, making it accessible in resource-poor settings. PMID:24077317

Simplification and its consequences in biological modelling: conclusions from a study of calcium oscillations in hepatocytes.

PubMed

Hetherington, James P J; Warner, Anne; Seymour, Robert M

2006-04-22

Systems Biology requires that biological modelling is scaled up from small components to system level. This can produce exceedingly complex models, which obscure understanding rather than facilitate it. The successful use of highly simplified models would resolve many of the current problems faced in Systems Biology. This paper questions whether the conclusions of simple mathematical models of biological systems are trustworthy. The simplification of a specific model of calcium oscillations in hepatocytes is examined in detail, and the conclusions drawn from this scrutiny generalized. We formalize our choice of simplification approach through the use of functional 'building blocks'. A collection of models is constructed, each a progressively more simplified version of a well-understood model. The limiting model is a piecewise linear model that can be solved analytically. We find that, as expected, in many cases the simpler models produce incorrect results. However, when we make a sensitivity analysis, examining which aspects of the behaviour of the system are controlled by which parameters, the conclusions of the simple model often agree with those of the richer model. The hypothesis that the simplified model retains no information about the real sensitivities of the unsimplified model can be very strongly ruled out by treating the simplification process as a pseudo-random perturbation on the true sensitivity data. We conclude that sensitivity analysis is, therefore, of great importance to the analysis of simple mathematical models in biology. Our comparisons reveal which results of the sensitivity analysis regarding calcium oscillations in hepatocytes are robust to the simplifications necessarily involved in mathematical modelling. For example, we find that if a treatment is observed to strongly decrease the period of the oscillations while increasing the proportion of the cycle during which cellular calcium concentrations are rising, without affecting the inter-spike or maximum calcium concentrations, then it is likely that the treatment is acting on the plasma membrane calcium pump.

Diagnostic value of different adherence measures using electronic monitoring and virologic failure as reference standards.

PubMed

Deschamps, Ann E; De Geest, Sabina; Vandamme, Anne-Mieke; Bobbaers, Herman; Peetermans, Willy E; Van Wijngaerden, Eric

2008-09-01

Nonadherence to antiretroviral therapy is a substantial problem in HIV and jeopardizes the success of treatment. Accurate measurement of nonadherence is therefore imperative for good clinical management but no gold standard has been agreed on yet. In a single-center prospective study nonadherence was assessed by electronic monitoring: percentage of doses missed and drug holidays and by three self reports: (1) a visual analogue scale (VAS): percentage of overall doses taken; (2) the Swiss HIV Cohort Study Adherence Questionnaire (SHCS-AQ): percentage of overall doses missed and drug holidays and (3) the European HIV Treatment Questionnaire (EHTQ): percentage of doses missed and drug holidays for each antiretroviral drug separately. Virologic failure prospectively assessed during 1 year, and electronic monitoring were used as reference standards. Using virologic failure as reference standard, the best results were for (1) the SHCS-AQ after electronic monitoring (sensitivity, 87.5%; specificity, 78.6%); (2) electronic monitoring (sensitivity, 75%; specificity, 85.6%), and (3) the VAS combined with the SHCS-AQ before electronic monitoring (sensitivity, 87.5%; specificity, 58.6%). The sensitivity of the complex EHTQ was less than 50%. Asking simple questions about doses taken or missed is more sensitive than complex questioning about each drug separately. Combining the VAS with the SHCS-AQ seems a feasible nonadherence measure for daily clinical practice. Self-reports perform better after electronic monitoring: their diagnostic value could be lower when given independently.

Simultaneous detection and differentiation of three genotypes of Brassica yellows virus by multiplex reverse transcription-polymerase chain reaction.

PubMed

Zhang, Xiaoyan; Peng, Yanmei; Wang, Ying; Zhang, Zongying; Li, Dawei; Yu, Jialin; Han, Chenggui

2016-11-22

Brassica yellows virus (BrYV), proposed to be a new polerovirus species, three distinct genotypes (BrYV-A, BrYV-B and BrYV-C) have been described. This study was to develop a simple, rapid, sensitive, cost-effective method for simultaneous detection and differentiation of three genotypes of BrYV. In this study, a multiplex reverse transcription-polymerase chain reaction (mRT-PCR) was developed for simultaneous detection and differentiation of the three genotypes of BrYV. The three genotypes of BrYV and Tunip yellows virus (TuYV) could be differentiated simultaneously using six optimized specific oligonucleotide primers, including one universal primer for detecting BrYV, three BrYV genotype-specific primers, and a pair of primers for specific detection of TuYV. Primers were designed from conserved regions of each virus and their specificity was confirmed by sequencing PCR products. The mRT-PCR products were 278 bp for BrYV-A, 674 bp for BrYV-B, 505 bp for BrYV-C, and 205 bp for TuYV. Amplification of three target genotypes was optimized by increasing the PCR annealing temperatures to 62 °C. One to three fragments specific for the virus genotypes were simultaneously amplified from infected samples and identified by their specific molecular sizes in agarose gel electrophoresis. No specific products could be amplified from cDNAs of other viruses which could infect crucifer crops. Detection limits of the plasmids for multiplex PCR were 100 fg for BrYV-A and BrYV-B, 10 pg for BrYV-C, and 1 pg for TuYV, respectively. The mRT-PCR was applied successfully for detection of three BrYV genotypes from field samples collected in China. The simple, rapid, sensitive, and cost-effective mRT-PCR was developed successfully for detection and differentiation of the three genotypes of BrYV.

Simple, multiplexed, PCR-based barcoding of DNA enables sensitive mutation detection in liquid biopsies using sequencing.

PubMed

Ståhlberg, Anders; Krzyzanowski, Paul M; Jackson, Jennifer B; Egyud, Matthew; Stein, Lincoln; Godfrey, Tony E

2016-06-20

Detection of cell-free DNA in liquid biopsies offers great potential for use in non-invasive prenatal testing and as a cancer biomarker. Fetal and tumor DNA fractions however can be extremely low in these samples and ultra-sensitive methods are required for their detection. Here, we report an extremely simple and fast method for introduction of barcodes into DNA libraries made from 5 ng of DNA. Barcoded adapter primers are designed with an oligonucleotide hairpin structure to protect the molecular barcodes during the first rounds of polymerase chain reaction (PCR) and prevent them from participating in mis-priming events. Our approach enables high-level multiplexing and next-generation sequencing library construction with flexible library content. We show that uniform libraries of 1-, 5-, 13- and 31-plex can be generated. Utilizing the barcodes to generate consensus reads for each original DNA molecule reduces background sequencing noise and allows detection of variant alleles below 0.1% frequency in clonal cell line DNA and in cell-free plasma DNA. Thus, our approach bridges the gap between the highly sensitive but specific capabilities of digital PCR, which only allows a limited number of variants to be analyzed, with the broad target capability of next-generation sequencing which traditionally lacks the sensitivity to detect rare variants. © The Author(s) 2016. Published by Oxford University Press on behalf of Nucleic Acids Research.

Evaluation of ICT filariasis card test using whole capillary blood: comparison with Knott's concentration and counting chamber methods.

PubMed

Njenga, S M; Wamae, C N

2001-10-01

An immunochromatographic card test (ICT) that uses fingerprick whole blood instead of serum for diagnosis of bancroftian filariasis has recently been developed. The card test was validated in the field in Kenya by comparing its sensitivity to the combined sensitivity of Knott's concentration and counting chamber methods. A total of 102 (14.6%) and 117 (16.7%) persons was found to be microfilaremic by Knott's concentration and counting chamber methods, respectively. The geometric mean intensities (GMI) were 74.6 microfilariae (mf)/ml and 256.5 mf/ml by Knott's concentration and counting chamber methods, respectively. All infected individuals detected by both Knott's concentration and counting chamber methods were also antigen positive by the ICT filariasis card test (100% sensitivity). Further, of 97 parasitologically amicrofilaremic persons, 24 (24.7%) were antigen positive by the ICT. The overall prevalence of antigenemia was 37.3%. Of 100 nonendemic area control persons, none was found to be filarial antigen positive (100% specificity). The results show that the new version of the ICT filariasis card test is a simple, sensitive, specific, and rapid test that is convenient in field settings.

[Validity of a standard questionnaire to assess physical activity for specific medical checkups and health guidance].

PubMed

Kawakami, Ryoko; Miyachi, Motohiko

2010-10-01

This study aimed to determine the validity of a standard questionnaire to assess amount of physical activity (PA) and cardiorespiratory fitness (VO2peak). A total of 483 men and women, aged 20 to 69 years, participated. The standard questionnaire included 3 items about exercise, PA, and walking speed. All questions were designed to require an answer of Yes or No. Subjects were classified into one of four groups regarding the number of Yes answers to the three questions, giving activity levels of 0 to 3. The amount of PA was measured objectively with a tn-axial accelerometer which could also calculate daily step counts, and the amounts of PA under 3 metabolic equivalents (METs) and at 3 METs or more. VO2peak. was measured by incremental cycle exercise tests with indirect calorimetry. The daily step counts, the amount of PA at 3 METs or more, and the VO2peak. were significantly higher in subjects who answered Yes to each question than in those who answered No. Sensitivity and specificity of each question were 62-73% and 45-71% for the amount of PA established with the "Exercise and Physical Activity Reference for Health Promotion 2006 (EPAR2006)". The sum of sensitivity and specificity was the highest when the cutoff value was activity level 2 (sensitivity 73%, specificity 68%). Sensitivity and specificity for VO2max established by EPAR2006 were lower than those for the amount of PA. These results suggest that only answering simple questions with a standard questionnaire is sufficient for estimation of PA levels for specific medical checkups and health guidance, even though the accuracy is somewhat limited.

Diagnostic performance of serological tests for swine brucellosis in the presence of false positive serological reactions.

PubMed

Dieste-Pérez, L; Blasco, J M; de Miguel, M J; Moriyón, I; Muñoz, P M

2015-04-01

Swine brucellosis caused by Brucella suis biovar 2 is an emerging disease in Europe. Currently used diagnostic tests for swine brucellosis detect antibodies to the O-polysaccharide (O-PS) of Brucella smooth lipopolysaccharide (S-LPS) but their specificity is compromised by false-positive serological reactions (FPSRs) when bacteria carrying cross-reacting O-PS infect pigs. FPSRs occur throughout Europe, and the only tool available for a specific B. suis diagnosis is the intradermal test with Brucella protein extracts free of O-PS or S-LPS. Using sera of 162 sows naturally infected by B. suis biovar 2, 406 brucellosis-free sows, and 218 pigs of brucellosis-free farms affected by FPSR, we assessed the diagnostic performance of an indirect ELISA with rough LPS (thus devoid of O-PS) and of gel immunodiffusion, counterimmunoelectrophoresis, latex agglutination and indirect ELISA with O-PS free proteins in comparison with several S-LPS tests (Rose Bengal, complement fixation, gel immunodiffusion and indirect ELISA). When adjusted to 100% specificity, the sensitivity of the rough LPS ELISA was very low (30%), and adoption of other cut-offs resulted in poor specificity/sensitivity ratios. Although their specificity was 100%, the sensitivity of protein tests (ELISA, latex agglutination, counterimmunoelectrophoresis, and gel immunodiffusion) was only moderate (45, 58, 61 and 63%, respectively). Among S-LPS tests, gel immunodiffusion was the only test showing acceptable sensitivity/specificity (68 and 100%, respectively). Despite these shortcomings, and when the purpose is to screen out FPSR at herd level, gel immunodiffusion tests may offer a technically simple and practical alternative to intradermal testing. Copyright © 2015 Elsevier B.V. All rights reserved.

The inclusion of N-terminal pro-brain natriuretic peptide in a sensitive screening strategy for systemic sclerosis-related pulmonary arterial hypertension: a cohort study

PubMed Central

2013-01-01

Introduction Pulmonary arterial hypertension (PAH) is a major cause of mortality in systemic sclerosis (SSc). Screening guidelines for PAH recommend multiple investigations, including annual echocardiography, which together have low specificity and may not be cost-effective. We sought to evaluate the predictive accuracy of serum N-terminal pro-brain natriuretic peptide (NT-proBNP) in combination with pulmonary function tests (PFT) (‘proposed’ algorithm) in a screening algorithm for SSc-PAH. Methods We evaluated our proposed algorithm (PFT with NT-proBNP) on 49 consecutive SSc patients with suspected pulmonary hypertension undergoing right heart catherisation (RHC). The predictive accuracy of the proposed algorithm was compared with existing screening recommendations, and is presented as sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV). Results Overall, 27 patients were found to have pulmonary hypertension (PH) at RHC, while 22 had no PH. The sensitivity, specificity, PPV and NPV of the proposed algorithm for PAH was 94.1%, 54.5%, 61.5% and 92.3%, respectively; current European Society of Cardiology (ESC)/European Respiratory Society (ERS) guidelines achieved a sensitivity, specificity, PPV and NPV of 94.1%, 31.8%, 51.6% and 87.5%, respectively. In an alternate case scenario analysis, estimating a PAH prevalence of 10%, the proposed algorithm achieved a sensitivity, specificity, PPV and NPV for PAH of 94.1%, 54.5%, 18.7% and 98.8%, respectively. Conclusions The combination of NT-proBNP with PFT is a sensitive, yet simple and non-invasive, screening strategy for SSc-PAH. Patients with a positive screening result can be referred for echocardiography, and further confirmatory testing for PAH. In this way, it may be possible to shift the burden of routine screening away from echocardiography. The findings of this study should be confirmed in larger studies. PMID:24246100

From anomalies to forecasts: Toward a descriptive model of decisions under risk, under ambiguity, and from experience.

PubMed

Erev, Ido; Ert, Eyal; Plonsky, Ori; Cohen, Doron; Cohen, Oded

2017-07-01

Experimental studies of choice behavior document distinct, and sometimes contradictory, deviations from maximization. For example, people tend to overweight rare events in 1-shot decisions under risk, and to exhibit the opposite bias when they rely on past experience. The common explanations of these results assume that the contradicting anomalies reflect situation-specific processes that involve the weighting of subjective values and the use of simple heuristics. The current article analyzes 14 choice anomalies that have been described by different models, including the Allais, St. Petersburg, and Ellsberg paradoxes, and the reflection effect. Next, it uses a choice prediction competition methodology to clarify the interaction between the different anomalies. It focuses on decisions under risk (known payoff distributions) and under ambiguity (unknown probabilities), with and without feedback concerning the outcomes of past choices. The results demonstrate that it is not necessary to assume situation-specific processes. The distinct anomalies can be captured by assuming high sensitivity to the expected return and 4 additional tendencies: pessimism, bias toward equal weighting, sensitivity to payoff sign, and an effort to minimize the probability of immediate regret. Importantly, feedback increases sensitivity to probability of regret. Simple abstractions of these assumptions, variants of the model Best Estimate and Sampling Tools (BEAST), allow surprisingly accurate ex ante predictions of behavior. Unlike the popular models, BEAST does not assume subjective weighting functions or cognitive shortcuts. Rather, it assumes the use of sampling tools and reliance on small samples, in addition to the estimation of the expected values. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

Autoantibody Approach for Serum-Based Detection of Head and Neck Cancer — EDRN Public Portal

Cancer.gov

Our long term goal is to improve survival of patients with head and neck squamous cell carcinoma (HNSCC) through early detection using simple noninvasive serum assays in an ELISA-like platform. The objective of this proposal is to improve and confirm the validity of a diagnostic serum assay based on a panel of cancer-specific biomarkers for early cancer detection in patients with HNSCC. Our central hypothesis is that the detection of antibody responses to HNSCC-specific antigens, using a panel of biomarkers, can provide sufficient sensitivity and specificity suitable for clinical testing in the primary setting to screen and diagnose HNSCC in high risk populations to improve early detection.

Development of simple and rapid assay to detect viral RNA of tick-borne encephalitis virus by reverse transcription-loop-mediated isothermal amplification.

PubMed

Hayasaka, Daisuke; Aoki, Kotaro; Morita, Kouichi

2013-03-04

Tick-borne encephalitis virus (TBEV) is a causative agent of acute central nervous system disease in humans. It has three subtypes, far eastern (FE), Siberian (Sib) and European (Eu) subtypes, which are distributed over a wide area of Europe and Asia. The objective of this study was to develop a simple and rapid assay for the detection of TBEV RNA by using reverse-transcriptase loop-mediated isothermal amplification (RT-LAMP) method that can differentiate the three subtypes of TBEV and can be used for clinical diagnosis and epidemiological study. Primers for TBEV-specific and subtype-specific RT-LAMP assay were designed to target the consensus sequence in NS1 of all subtypes and the consensus sequence in the E gene of each subtype, respectiveluy. In vitro transcribed RNA of Oshima strain that belongs to FE subtype was serially diluted and used to examine the sensitivity of the assay. Cross-reactivity of subtype-specific RT-LAMP assay was tested by using the RNA of Oshima and Sofjin (FE), IR-99 (Sib) and Hochosterwitz (Eu) strains. RNA extracted from the mixtures of TBEV and ticks, and of TBEV and human blood, and the mouse tissues infected with TBEV, were evaluated in the assay. Positive amplification was observed by real-time monitoring of turbidity and by visual detection of color change. The sensitivity of TBEV-specific RT-LAMP assay was 102 copies of target RNA per reaction volume. FE-specific RT-LAMP assay amplified viral genes of Oshima and Sofjin strains but not of IR-99 and Hochosterwitz strains, and of Japanese encephalitis virus. RT-LAMP assay for Sib and for Eu specifically amplified viral genes of IR-99 and Hochosterwitz strains, respectively. We also showed that tick or human blood extract did not inhibit the amplification of viral gene during the assay. Furthermore, we confirmed that the TBEV RT-LAMP could detect virus RNA from peripheral and central nervous system tissues of laboratory mice infected with TBEV. TBEV RT-LAMP assay offers a sensitive, specific, rapid and easy-to-handle method for the detection of TBEV RNA in tick samples and this may be applied in the clinical samples collected from TBE-suspected patients.

A prospective field evaluation of an enzyme immunoassay: Detection of eastern equine encephalomyelitis virus antigen in pools of Culiseta melanura

USGS Publications Warehouse

Scott, T.W.; Olson, J.G.; Lewis, T.E.; Carpenter, J.W.; Lorenz, L.H.; Lembeck, L.A.; Joseph, S.R.; Pagac, B.B.

1987-01-01

A prospective field study was conducted to determine the sensitivity and specificity of an enzyme immunoassay (EIA) compared to virus isolation in cell culture for the detection of eastern equine encephalomyelitis (EEE) virus in naturally infected mosquitoes. A total of 10,811 adult female Culiseta melanura were collected in light traps during 1985 from four locations in Maryland. Eastern equine encephalomyelitis virus was isolated from 5 of 495 mosquito pools in African green monkey kidney and baby hamster kidney cell cultures. All five virus-infected pools were detected by the EIA, and all 490 uninfected pools were correctly scored as not containing virus. The EIA did not produce false positive or false negative results. Results support the assertion of previous researchers that the antigen detection EIA is a rapid, sensitive, specific, and simple alternative to traditional bioassays for the detection of EEE virus in mosquitoes.

Two-question depression-screeners - the solution to all problems?

PubMed

Albani, Cornelia; Bailer, Harald; Blaser, Gerd; Brähler, Elmar; Geyer, Michael; Grulke, Norbert

2006-04-01

Depression constitutes a considerable issue in medicine and it is anticipated that the amount of people suffering from affective disorders will increase significantly. It would be useful to have a simple, fast screening procedure which would help detect depression. In four recently published articles a two-question depression-screener is recommended. Sensitivity, specificity, likelihood ratios, negative and positive predictive values were compared. For four different clinical samples and one sample that was representative of the German population the prevalence for depression ranged from 6.9 % to 18.1 %. Sensitivity and specificity reached values from 72.6 % to 96.6 % and from 56.9 % to 90.0 % respectively. All negative predictive values were high (< 97 %) opposed to positive predictive values (17.8 % to 38.5 %). Overall, it seems that the two-question screenings are well suited for the exclusion of a major depression. It is possible that regular screening could further lower the percentage of undiagnosed cases.

Design, optimisation and preliminary validation of a human specific loop-mediated amplification assay for the rapid detection of human DNA at forensic crime scenes.

PubMed

Hird, H J; Brown, M K

2017-11-01

The identification of samples at a crime scene which require forensic DNA typing has been the focus of recent research interest. We propose a simple, but sensitive analysis system which can be deployed at a crime scene to identify crime scene stains as human or non-human. The proposed system uses the isothermal amplification of DNA in a rapid assay format, which returns results in as little as 30min from sampling. The assay system runs on the Genie II device, a proven in-field detection system which could be deployed at a crime scene. The results presented here demonstrate that the system was sufficiently specific and sensitive and was able to detect the presence of human blood, semen and saliva on mock forensic samples. Copyright © 2017. Published by Elsevier B.V.

Engineering the temporal response of photoconductive photodetectors via selective introduction of surface trap states.

PubMed

Konstantatos, Gerasimos; Levina, Larissa; Fischer, Armin; Sargent, Edward H

2008-05-01

Photoconductive photodetectors fabricated using simple solution-processing have recently been shown to exhibit high gains (>1000) and outstanding sensitivities ( D* > 10(13) Jones). One ostensible disadvantage of exploiting photoconductive gain is that the temporal response is limited by the release of carriers from trap states. Here we show that it is possible to introduce specific chemical species onto the surfaces of colloidal quantum dots to produce only a single, desired trap state having a carefully selected lifetime. In this way we demonstrate a device that exhibits an attractive photoconductive gain (>10) combined with a response time ( approximately 25 ms) useful in imaging. We achieve this by preserving a single surface species, lead sulfite, while eliminating lead sulfate and lead carboxylate. In doing so we preserve the outstanding sensitivity of these devices, achieving a specific detectivity of 10(12) Jones in the visible, while generating a temporal response suited to imaging applications.

Sensitivity and specificity of fluorescence microlymphography for detecting lymphedema of the lower extremity.

PubMed

Keo, Hong H; Schilling, Marianne; Büchel, Roland; Gröchenig, Ernst; Engelberger, Rolf P; Willenberg, Torsten; Baumgartner, Iris; Gretener, Silvia B

2013-06-01

Fluorescence microlymphography (FML) is used to visualize the lymphatic capillaries. A maximum spread of the fluorescence dye of ≥ 12 mm has been suggested for the diagnosis of lymphedema. However, data on sensitivity and specificity are lacking. The aim of this study was to investigate the accuracy of FML for diagnosing lymphedema in patients with leg swelling. Patients with lower extremity swelling were clinically assessed and separated into lymphedema and non-lymphatic edema groups. FML was studied in all affected legs and the maximum spread of lymphatic capillaries was measured. Test accuracy and receiver operator characteristic (ROC) analysis was performed to assess possible threshold values that predict lymphedema. Between March 2008 and August 2011 a total of 171 patients (184 legs) with a median age of 43.5 (IQR 24, 54) years were assessed. Of those, 94 (51.1%) legs were diagnosed with lymphedema. The sensitivity, specificity, positive and negative likelihood ratio and positive and negative predictive value were 87%, 64%, 2.45, 0.20, 72% and 83% for the 12-mm cut-off level and 79%, 83%, 4.72, 0.26, 83% and 79% for the 14-mm cut-off level, respectively. The area under the ROC curve was 0.82 (95% CI: 0.76, 0.88). Sensitivity was higher in the secondary versus primary lymphedema (95.0% vs 74.3%, p = 0.045). No major adverse events were observed. In conclusion, FML is a simple and safe technique for detecting lymphedema in patients with leg swelling. A cut-off level of ≥ 14-mm maximum spread has a high sensitivity and high specificity of detecting lymphedema and should be chosen.

Dual Recognition Strategy for Specific and Sensitive Detection of Bacteria Using Aptamer-Coated Magnetic Beads and Antibiotic-Capped Gold Nanoclusters.

PubMed

Cheng, Dan; Yu, Mengqun; Fu, Fei; Han, Weiye; Li, Gan; Xie, Jianping; Song, Yang; Swihart, Mark T; Song, Erqun

2016-01-05

Food poisoning and infectious diseases caused by pathogenic bacteria such as Staphylococcus aureus (SA) are serious public health concerns. A method of specific, sensitive, and rapid detection of such bacteria is essential and important. This study presents a strategy that combines aptamer and antibiotic-based dual recognition units with magnetic enrichment and fluorescent detection to achieve specific and sensitive quantification of SA in authentic specimens and in the presence of much higher concentrations of other bacteria. Aptamer-coated magnetic beads (Apt-MB) were employed for specific capture of SA. Vancomycin-stabilized fluorescent gold nanoclusters (AuNCs@Van) were prepared by a simple one-step process and used for sensitive quantification of SA in the range of 32-10(8) cfu/mL with the detection limit of 16 cfu/mL via a fluorescence intensity measurement. And using this strategy, about 70 cfu/mL of SA in complex samples (containing 3 × 10(8) cfu/mL of other different contaminated bacteria) could be successfully detected. In comparison to prior studies, the developed strategy here not only simplifies the preparation procedure of the fluorescent probes (AuNCs@Van) to a great extent but also could sensitively quantify SA in the presence of much higher concentrations of other bacteria directly with good accuracy. Moreover, the aptamer and antibiotic used in this strategy are much less expensive and widely available compared to common-used antibodies, making it cost-effective. This general aptamer- and antibiotic-based dual recognition strategy, combined with magnetic enrichment and fluorescent detection of trace bacteria, shows great potential application in monitoring bacterial food contamination and infectious diseases.

Simple and ultra-fast recognition and quantitation of compounded monoclonal antibodies: Application to flow injection analysis combined to UV spectroscopy and matching method.

PubMed

Jaccoulet, E; Schweitzer-Chaput, A; Toussaint, B; Prognon, P; Caudron, E

2018-09-01

Compounding of monoclonal antibody (mAbs) constantly increases in hospital. Quality control (QC) of the compounded mAbs based on quantification and identification is required to prevent potential errors and fast method is needed to manage outpatient chemotherapy administration. A simple and ultra-fast (less than 30 s) method using flow injection analysis associated to least square matching method issued from the analyzer software was performed and evaluated for the routine hospital QC of three compounded mAbs: bevacizumab, infliximab and rituximab. The method was evaluated through qualitative and quantitative parameters. Preliminary analysis of the UV absorption and second derivative spectra of the mAbs allowed us to adapt analytical conditions according to the therapeutic range of the mAbs. In terms of quantitative QC, linearity, accuracy and precision were assessed as specified in ICH guidelines. Very satisfactory recovery was achieved and the RSD (%) of the intermediate precision were less than 1.1%. Qualitative analytical parameters were also evaluated in terms of specificity, sensitivity and global precision through a matrix of confusion. Results showed to be concentration and mAbs dependant and excellent (100%) specificity and sensitivity were reached within specific concentration range. Finally, routine application on "real life" samples (n = 209) from different batch of the three mAbs complied with the specifications of the quality control i.e. excellent identification (100%) and ± 15% of targeting concentration belonging to the calibration range. The successful use of the combination of second derivative spectroscopy and partial least square matching method demonstrated the interest of FIA for the ultra-fast QC of mAbs after compounding using matching method. Copyright © 2018 Elsevier B.V. All rights reserved.

A highly sensitive and selective aptamer-based colorimetric sensor for the rapid detection of PCB 77.

PubMed

Cheng, Ruojie; Liu, Siyao; Shi, Huijie; Zhao, Guohua

2018-01-05

A highly sensitive, specific and simple colorimetric sensor based on aptamer was established for the detection of polychlorinated biphenyls (PCB 77). The use of unmodified gold nanoparticles as a colorimetric probe for aptamer sensors enabled the highly sensitive and selective detection of polychlorinated biphenyls (PCB 77). A linear range of 0.5nM to 900nM was obtained for the colorimetric assay with a minimum detection limit of 0.05nM. In addition, by the methods of circular dichroism, UV and naked eyes, we found that the 35 base fragments retained after cutting 5 bases from the 5 'end of aptamer plays the most significant role in the PCB 77 specific recognition process. We found a novel way to truncated nucleotides to optimize the detection of PCB 77, and the selected nucleotides also could achieve high affinity with PCB 77. At the same time, the efficient detection of the PCB 77 by our colorimetric sensor in the complex environmental water samples was realized, which shows a good application prospect. Copyright © 2017 Elsevier B.V. All rights reserved.

A virus-MIPs fluorescent sensor based on FRET for highly sensitive detection of JEV.

PubMed

Liang, Caishuang; Wang, Huan; He, Kui; Chen, Chunyan; Chen, Xiaoming; Gong, Hang; Cai, Changqun

2016-11-01

Major stumbling blocks in the recognition and detection of virus are the unstable biological recognition element or the complex detection means. Here a fluorescent sensor based on virus-molecular imprinted polymers (virus-MIPs) was designed for specific recognition and highly sensitive detection of Japanese encephalitis virus (JEV). The virus-MIPs were anchored on the surface of silica microspheres modified by fluorescent dye, pyrene-1-carboxaldehyde (PC). The fluorescence intensity of PC can be enhanced by the principle of fluorescence resonance energy transfer (FRET), where virus acted as energy donor and PC acted as energy acceptor. The enhanced fluorescence intensity was proportional to the concentration of virus in the range of 24-960pM, with a limit of detection (LOD, 3σ) of 9.6pM, and the relative standard deviation was 1.99%. In additional, the specificity study confirmed the resultant MIPs has high-selectivity for JEV. This sensor would become a new key for the detection of virus because of its high sensitive, simple operation, high stability and low cost. Copyright © 2016. Published by Elsevier B.V.

Simple, sensitive, selective and validated spectrophotometric methods for the estimation of a biomarker trigonelline from polyherbal gels

NASA Astrophysics Data System (ADS)

Chopra, Shruti; Motwani, Sanjay K.; Ahmad, Farhan J.; Khar, Roop K.

2007-11-01

Simple, accurate, reproducible, selective, sensitive and cost effective UV-spectrophotometric methods were developed and validated for the estimation of trigonelline in bulk and pharmaceutical formulations. Trigonelline was estimated at 265 nm in deionised water and at 264 nm in phosphate buffer (pH 4.5). Beer's law was obeyed in the concentration ranges of 1-20 μg mL -1 ( r2 = 0.9999) in deionised water and 1-24 μg mL -1 ( r2 = 0.9999) in the phosphate buffer medium. The apparent molar absorptivity and Sandell's sensitivity coefficient were found to be 4.04 × 10 3 L mol -1 cm -1 and 0.0422 μg cm -2/0.001A in deionised water; and 3.05 × 10 3 L mol -1 cm -1 and 0.0567 μg cm -2/0.001A in phosphate buffer media, respectively. These methods were tested and validated for various parameters according to ICH guidelines. The detection and quantitation limits were found to be 0.12 and 0.37 μg mL -1 in deionised water and 0.13 and 0.40 μg mL -1 in phosphate buffer medium, respectively. The proposed methods were successfully applied for the determination of trigonelline in pharmaceutical formulations (vaginal tablets and bioadhesive vaginal gels). The results demonstrated that the procedure is accurate, precise, specific and reproducible (percent relative standard deviation <2%), while being simple and less time consuming and hence can be suitably applied for the estimation of trigonelline in different dosage forms and dissolution studies.

Novel aptamer-linked nanoconjugate approach for detection of waterborne bacterial pathogens: an update

NASA Astrophysics Data System (ADS)

Singh, Gulshan; Manohar, Murli; Adegoke, Anthony Ayodeji; Stenström, Thor Axel; Shanker, Rishi

2017-01-01

The lack of microbiologically safe water in underdeveloped nations is the prime cause of infectious disease outbreaks. The need for the specific identification and detection of microorganisms encourages the development of advanced, rapid, sensitive and highly specific methods for the monitoring of pathogens and management of potential risk to human health. The rapid molecular assays based on detection of specific molecular signatures offer advantages over conventional methods in terms of specificity and sensitivity but require complex instrumentation and skilled personnel. Nanotechnology is an emerging area and provides a robust approach for the identification of pathogenic microorganism utilizing the peculiar properties of nanomaterials, i.e. small size (1-100 nm) and large surface area. This emerging technology promises to fulfill the urgent need of a novel strategy to enhance the bacterial identification and quantitation in the environment. In this context, the peculiar properties of gold nanoparticles, their plasmonic shifts, and changes in magnetic properties have been utilized for the simple and cost-effective detection of bacterial nucleic acids, antigens and toxins with quite improved sensitivity. One of the promising leads to develop an advance detection method might be the coupling of nucleic acid aptamers (capable of interacting specifically with bacteria, protozoa, and viruses) with nanomaterials. Such aptamer-nano conjugate can be used for the specific recognition of infectious agents in different environmental matrices. This review summarizes the application of nanotechnology in the area of pathogen detection and discusses the prospects of coupling nucleic acid aptamers with nanoparticles for the specific detection of targeted pathogens.

Predicting the onset of hazardous alcohol drinking in primary care: development and validation of a simple risk algorithm.

PubMed

Bellón, Juan Ángel; de Dios Luna, Juan; King, Michael; Nazareth, Irwin; Motrico, Emma; GildeGómez-Barragán, María Josefa; Torres-González, Francisco; Montón-Franco, Carmen; Sánchez-Celaya, Marta; Díaz-Barreiros, Miguel Ángel; Vicens, Catalina; Moreno-Peral, Patricia

2017-04-01

Little is known about the risk of progressing to hazardous alcohol use in abstinent or low-risk drinkers. To develop and validate a simple brief risk algorithm for the onset of hazardous alcohol drinking (HAD) over 12 months for use in primary care. Prospective cohort study in 32 health centres from six Spanish provinces, with evaluations at baseline, 6 months, and 12 months. Forty-one risk factors were measured and multilevel logistic regression and inverse probability weighting were used to build the risk algorithm. The outcome was new occurrence of HAD during the study, as measured by the AUDIT. From the lists of 174 GPs, 3954 adult abstinent or low-risk drinkers were recruited. The 'predictAL-10' risk algorithm included just nine variables (10 questions): province, sex, age, cigarette consumption, perception of financial strain, having ever received treatment for an alcohol problem, childhood sexual abuse, AUDIT-C, and interaction AUDIT-C*Age. The c-index was 0.886 (95% CI = 0.854 to 0.918). The optimal cutoff had a sensitivity of 0.83 and specificity of 0.80. Excluding childhood sexual abuse from the model (the 'predictAL-9'), the c-index was 0.880 (95% CI = 0.847 to 0.913), sensitivity 0.79, and specificity 0.81. There was no statistically significant difference between the c-indexes of predictAL-10 and predictAL-9. The predictAL-10/9 is a simple and internally valid risk algorithm to predict the onset of hazardous alcohol drinking over 12 months in primary care attendees; it is a brief tool that is potentially useful for primary prevention of hazardous alcohol drinking. © British Journal of General Practice 2017.

Predicting the onset of hazardous alcohol drinking in primary care: development and validation of a simple risk algorithm

PubMed Central

Bellón, Juan Ángel; de Dios Luna, Juan; King, Michael; Nazareth, Irwin; Motrico, Emma; GildeGómez-Barragán, María Josefa; Torres-González, Francisco; Montón-Franco, Carmen; Sánchez-Celaya, Marta; Díaz-Barreiros, Miguel Ángel; Vicens, Catalina; Moreno-Peral, Patricia

2017-01-01

Background Little is known about the risk of progressing to hazardous alcohol use in abstinent or low-risk drinkers. Aim To develop and validate a simple brief risk algorithm for the onset of hazardous alcohol drinking (HAD) over 12 months for use in primary care. Design and setting Prospective cohort study in 32 health centres from six Spanish provinces, with evaluations at baseline, 6 months, and 12 months. Method Forty-one risk factors were measured and multilevel logistic regression and inverse probability weighting were used to build the risk algorithm. The outcome was new occurrence of HAD during the study, as measured by the AUDIT. Results From the lists of 174 GPs, 3954 adult abstinent or low-risk drinkers were recruited. The ‘predictAL-10’ risk algorithm included just nine variables (10 questions): province, sex, age, cigarette consumption, perception of financial strain, having ever received treatment for an alcohol problem, childhood sexual abuse, AUDIT-C, and interaction AUDIT-C*Age. The c-index was 0.886 (95% CI = 0.854 to 0.918). The optimal cutoff had a sensitivity of 0.83 and specificity of 0.80. Excluding childhood sexual abuse from the model (the ‘predictAL-9’), the c-index was 0.880 (95% CI = 0.847 to 0.913), sensitivity 0.79, and specificity 0.81. There was no statistically significant difference between the c-indexes of predictAL-10 and predictAL-9. Conclusion The predictAL-10/9 is a simple and internally valid risk algorithm to predict the onset of hazardous alcohol drinking over 12 months in primary care attendees; it is a brief tool that is potentially useful for primary prevention of hazardous alcohol drinking. PMID:28360074

Rapid identification of drug-type strains in Cannabis sativa using loop-mediated isothermal amplification assay.

PubMed

Kitamura, Masashi; Aragane, Masako; Nakamura, Kou; Watanabe, Kazuhito; Sasaki, Yohei

2017-01-01

In Cannabis sativa L., tetrahydrocannabinol (THC) is the primary psychoactive compound and exists as the carboxylated form, tetrahydrocannabinolic acid (THCA). C. sativa is divided into two strains based on THCA content-THCA-rich (drug-type) strains and THCA-poor (fiber-type) strains. Both strains are prohibited by law in many countries including Japan, whereas the drug-type strains are regulated in Canada and some European countries. As the two strains cannot be discriminated by morphological analysis, a simple method for identifying the drug-type strains is required for quality control in legal cultivation and forensic investigation. We have developed a novel loop-mediated isothermal amplification (LAMP) assay for identifying the drug-type strains of C. sativa. We designed two selective LAMP primer sets for on-site or laboratory use, which target the drug-type THCA synthase gene. The LAMP assay was accomplished within approximately 40 min. The assay showed high specificity for the drug-type strains and its sensitivity was the same as or higher than that of conventional polymerase chain reaction. We also showed the effectiveness of melting curve analysis that was conducted after the LAMP assay. The melting temperature values of the drug-type strains corresponded to those of the cloned drug-type THCA synthase gene, and were clearly different from those of the cloned fiber-type THCA synthase gene. Moreover, the LAMP assay with simple sample preparation could be accomplished within 1 h from sample treatment to identification without the need for special devices or techniques. Our rapid, sensitive, specific, and simple assay is expected to be applicable to laboratory and on-site detection.

Sleep disturbance in alcoholism: proposal of a simple measurement, and results from a 24-week randomized controlled study of alcohol-dependent patients assessing acamprosate efficacy.

PubMed

Perney, Pascal; Lehert, Philippe; Mason, Barbara J

2012-01-01

Sleep disturbance symptom (SDS) is commonly reported in alcoholic patients. Polysomnography studies suggested that acamprosate decreased SDS. We assessed this hypothesis by using data of a randomized controlled trial. As a secondary objective, we suggested and tested the validity of a simple measurement of SDS based on the Hamilton depression and anxiety inventory subset. We re-analysed a multi-center study evaluating the efficacy of acamprosate compared with placebos on alcohol-dependent patients in concentrating on SDS change in time. The Sleep sum score index (SAEI) was built from check-lists on adverse effects reported at each visit and constituted our main endpoint. We also tested the validity of the short sleep index (SSI) defined by the four sleep items of the Hamilton depression and anxiety scales. Statistical analyses were conducted on an intention to treat basis. A total of 592 patients were included, and 292 completed the 6-month trial. Compared with SAEI considered as our reference, the observed specificity and sensitivity of SSI were 91.6 and 87.6%. From 40.2% of patients experiencing SDS at baseline, this proportion decreased until 26.1% at M6 in the placebo group and 19.5% in the acamprosate group (relative risk placebo/acamprosate = 1.49, 95% confidence interval 1.10, 1.98, P = 0.04). Treating alcoholic patients to enhance abstinence has a beneficial effect in reducing SDS, and the duration of abstinence during the treatment constitutes the main positive factor. An additional effect of acamprosate is conjectured from its effect on the glutamatergic tone. The SSI constitutes a simple, reasonably sensitive and specific instrument tool to measure SDS.

Right ventricular end-systolic area as a simple first-line marker predicting right ventricular enlargement and decreased systolic function in children referred for cardiac magnetic resonance imaging.

PubMed

Barczuk-Falęcka, M; Małek, Ł A; Roik, D; Werys, K; Werner, B; Brzewski, M

2018-06-01

To assess the accuracy of simple cardiovascular magnetic resonance imaging (CMR) parameters for first-line analysis of right ventricle (RV) dysfunction in children to identify those who require in-depth analysis and those in whom simple assessment is sufficient. Sixty paediatric CMR studies were analysed. The following CMR parameters were measured: RV end-diastolic and end-systolic area (4CH EDA and 4CH ESA), fractional area change (FAC), RV diameter in end-diastole (RVD1), tricuspid annular plane systolic excursion (TAPSE), and RV outflow tract diameter in end-diastole (RVOT prox). They were correlated with RV end-diastolic volume (RVEDVI) and RV ejection fraction (RVEF). RVEDVI correlated best with 4CH ESA (r=0.85, <0.001) and EDA (r=0.82, <0.001). For RVEF only a moderate reverse correlation was found for 4CH ESA (-0.56, <0.001), 4CH EDA (-0.49, 0.001) and positive correlation for FAC (0.49, <0.001). There was no correlation between TAPSE and RVEF and only weak between RVD1 and RVEDVI. A 4CH ESA cut-off value of 8.5 cm 2 /m 2 had a very high diagnostic accuracy for predicting an enlarged RV (AUC=0.912, p<0.001, sensitivity 92.3%, specificity 79%) and a cut-off value of 10.5 cm 2 /m 2 was also a good predictor of depressed RV systolic function (AUC=0.873, p<0.001, sensitivity 83%, specificity 89%). For routine screening in clinical practice, 4CH ESA seems a reliable and easy method to identify patients with RV dysfunction. Copyright © 2018 The Royal College of Radiologists. Published by Elsevier Ltd. All rights reserved.

Electrochemical aptasensor for detecting tetracycline in milk

NASA Astrophysics Data System (ADS)

Hanh Le, Thi; Phuc Pham, Van; Huyen La, Thi; Binh Phan, Thi; Huan Le, Quang

2016-03-01

A rapid, simple and sensitive biosensor system for tetracycline detection is very important in food safety. In this paper we developed a label-free aptasensor for electrochemical detection of tetracycline. According to the electrochemical impendence spectroscopy (EIS) analysis, there was a linear relationship between the concentration of tetracycline and the electron transfer resistance from 10 to 3000 ng ml-1 of the tetracycline concentration. The detection limit was 10 ng ml-1 in 15 min detection duration. The prepared aptasensor showed a good reproducibility with an acceptable stability in tetracycline detection. The recoveries of tetracycline in spiked milk samples were in the range of 88.1%-94.2%. The aptasensor has sensitivity 98% and specificity of 100%.

The 'sniffer-patch' technique for detection of neurotransmitter release.

PubMed

Allen, T G

1997-05-01

A wide variety of techniques have been employed for the detection and measurement of neurotransmitter release from biological preparations. Whilst many of these methods offer impressive levels of sensitivity, few are able to combine sensitivity with the necessary temporal and spatial resolution required to study quantal release from single cells. One detection method that is seeing a revival of interest and has the potential to fill this niche is the so-called 'sniffer-patch' technique. In this article, specific examples of the practical aspects of using this technique are discussed along with the procedures involved in calibrating these biosensors to extend their applications to provide quantitative, in addition to simple qualitative, measurements of quantal transmitter release.

Development of an isothermal recombinase polymerase amplification assay for rapid detection of pseudorabies virus.

PubMed

Yang, Yang; Qin, Xiaodong; Zhang, Wei; Li, Zhiyong; Zhang, Shuaijun; Li, Yanmin; Zhang, Zhidong

2017-06-01

Recombinase polymerase amplification assays using real-time fluorescent detection (real-time RPA assay) and lateral flow dipstick (RPA LFD assay) were developed targeting the gD gene of pseudorabies virus (PRV). Both assays were performed at 39 °C within 20 min. The sensitivity of the real-time RPA assay and the RPA LFD assay was 100 copies per reaction and 160 copies per reaction, respectively. Both assays did not detect DNAs from other virus or PRV negative samples. Therefore, the developed RPA assays provide a rapid, simple, sensitive and specific alternative tool for detection of PRV. Copyright © 2017. Published by Elsevier Ltd.

Ultra-sensitive detection of kanamycin for food safety using a reduced graphene oxide-based fluorescent aptasensor

NASA Astrophysics Data System (ADS)

Ha, Na-Reum; Jung, In-Pil; La, Im-Joung; Jung, Ho-Sup; Yoon, Moon-Young

2017-01-01

Overuse of antibiotics has caused serious problems, such as appearance of super bacteria, whose accumulation in the human body through the food chain is a concern. Kanamycin is a common antibiotic used to treat diverse infections; however, residual kanamycin can cause many side effects in humans. Thus, development of an ultra-sensitive, precise, and simple detection system for residual kanamycin in food products is urgently needed for food safety. In this study, we identified kanamycin-binding aptamers via a new screening method, and truncated variants were analyzed for optimization of the minimal sequence required for target binding. We found various aptamers with high binding affinity from 34.7 to 669 nanomolar Kdapp values with good specificity against kanamycin. Furthermore, we developed a reduced graphene oxide (RGO)-based fluorescent aptasensor for kanamycin detection. In this system, kanamycin was detected at a concentration as low as 1 pM (582.6 fg/mL). In addition, this method could detect kanamycin accurately in kanamycin-spiked blood serum and milk samples. Consequently, this simple, rapid, and sensitive kanamycin detection system with newly structural and functional analysis aptamer exhibits outstanding detection compared to previous methods and provides a new possibility for point of care testing and food safety.

Improved Analytical Sensitivity of Lateral Flow Assay using Sponge for HBV Nucleic Acid Detection.

PubMed

Tang, Ruihua; Yang, Hui; Gong, Yan; Liu, Zhi; Li, XiuJun; Wen, Ting; Qu, ZhiGuo; Zhang, Sufeng; Mei, Qibing; Xu, Feng

2017-05-02

Hepatitis B virus (HBV) infection is a serious public health problem, which can be transmitted through various routes (e.g., blood donation) and cause hepatitis, liver cirrhosis and liver cancer. Hence, it is necessary to do diagnostic screening for high-risk HBV patients in these transmission routes. Nowadays, protein-based technologies have been used for HBV testing, which however involve the issues of large sample volume, antibody instability and poor specificity. Nucleic acid hybridization-based lateral flow assay (LFA) holds great potential to address these limitations due to its low-cost, rapid, and simple features, but the poor analytical sensitivity of LFA restricts its application. In this study, we developed a low-cost, simple and easy-to-use method to improve analytical sensitivity by integrating sponge shunt into LFA to decrease the fluid flow rate. The thickness, length and hydrophobicity of the sponge shunt were sequentially optimized, and achieved 10-fold signal enhancement in nucleic acid testing of HBV as compared to the unmodified LFA. The enhancement was further confirmed by using HBV clinical samples, where we achieved the detection limit of 10 3 copies/ml as compared to 10 4 copies/ml in unmodified LFA. The improved LFA holds great potential for diseases diagnostics, food safety control and environment monitoring at point-of-care.

Electrochemical affinity biosensors for fast detection of gene-specific methylations with no need for bisulfite and amplification treatments.

PubMed

Povedano, Eloy; Vargas, Eva; Montiel, Víctor Ruiz-Valdepeñas; Torrente-Rodríguez, Rebeca M; Pedrero, María; Barderas, Rodrigo; Segundo-Acosta, Pablo San; Peláez-García, Alberto; Mendiola, Marta; Hardisson, David; Campuzano, Susana; Pingarrón, José M

2018-04-23

This paper describes two different electrochemical affinity biosensing approaches for the simple, fast and bisulfite and PCR-free quantification of 5-methylated cytosines (5-mC) in DNA using the anti-5-mC antibody as biorecognition element. One of the biosensing approaches used the anti-5-mC as capture bioreceptor and a sandwich type immunoassay, while the other one involved the use of a specific DNA probe and the anti-5-mC as a detector bioreceptor of the captured methylated DNA. Both strategies, named for simplicity in the text as immunosensor and DNA sensor, respectively, were implemented on the surface of magnetic microparticles and the transduction was accomplished by amperometry at screen-printed carbon electrodes by means of the hydrogen peroxide/hydroquinone system. The resulting amperometric biosensors demonstrated reproducibility throughout the entire protocol, sensitive determination with no need for using amplification strategies, and competitiveness with the conventional enzyme-linked immunosorbent assay methodology and the few electrochemical biosensors reported so far in terms of simplicity, sensitivity and assay time. The DNA sensor exhibited higher sensitivity and allowed the detection of the gene-specific methylations conversely to the immunosensor, which detected global DNA methylation. In addition, the DNA sensor demonstrated successful applicability for 1 h-analysis of specific methylation in two relevant tumor suppressor genes in spiked biological fluids and in genomic DNA extracted from human glioblastoma cells.

Evaluation of erythrocyte dysmorphism by light microscopy with lowering of the condenser lens: A simple and efficient method.

PubMed

Barros Silva, Gyl Eanes; Costa, Roberto Silva; Ravinal, Roberto Cuan; Saraiva e Silva, Jucélia; Dantas, Marcio; Coimbra, Terezila Machado

2010-03-01

To demonstrate that the evaluation of erythrocyte dysmorphism by light microscopy with lowering of the condenser lens (LMLC) is useful to identify patients with a haematuria of glomerular or non-glomerular origin. A comparative double-blind study between phase contrast microscopy (PCM) and LMLC is reported to evaluate the efficacy of these techniques. Urine samples of 39 patients followed up for 9 months were analyzed, and classified as glomerular and non-glomerular haematuria. The different microscopic techniques were compared using receiver-operator curve (ROC) analysis and area under curve (AUC). Reproducibility was assessed by coefficient of variation (CV). Specific cut-offs were set for each method according to their best rate of specificity and sensitivity as follows: 30% for phase contrast microscopy and 40% for standard LMLC, reaching in the first method the rate of 95% and 100% of sensitivity and specificity, respectively, and in the second method the rate of 90% and 100% of sensitivity and specificity, respectively. In ROC analysis, AUC for PCM was 0.99 and AUC for LMLC was 0.96. The CV was very similar in glomerular haematuria group for PCM (35%) and LMLC (35.3%). LMLC proved to be effective in contributing to the direction of investigation of haematuria, toward the nephrological or urological side. This method can substitute PCM when this equipment is not available.

A sensitive electrochemical biosensor for detection of protein kinase A activity and inhibitors based on Phos-tag and enzymatic signal amplification.

PubMed

Yin, Huanshun; Wang, Mo; Li, Bingchen; Yang, Zhiqing; Zhou, Yunlei; Ai, Shiyun

2015-01-15

A simple, highly sensitive and selective electrochemical assay is developed for the detection of protein kinase A (PKA) activity based on the specific recognition utility of Phos-tag for kinase-induced phosphopeptides and enzymatic signal amplification. When the substrate peptide was phosphorylated by PKA reaction, they could specifically bind with Phos-tag-biotin in the presence of Zn(2+) through the formation of a specific noncovalent complex with the phosphomonoester dianion in phosphorylated peptides. Through the further specific interaction between biotin and avidin, avidin functionalized horseradish peroxidase (HRP) can be captured on the electrode surface. Under the catalytic effect of HRP, a sensitive electrochemical signal for benzoquinone was obtained, which was related to PKA activity. Under the optimal experiment conditions, the proposed electrochemical method presented dynamic range from 0.5 to 25 unit/mL with low detection limit of 0.15 unit/mL. This new detection strategy was also successfully applied to analyze the inhibition effect of inhibitors (ellagic acid and H-89) on PKA activity and monitored the PKA activity in cell lysates. Therefore, this Phos-tag-based electrochemical assay offers an alternative platform for PKA activity assay and inhibitor screening, and thus it might be a valuable tool for development of targeted therapy and clinical diagnosis. Copyright © 2014 Elsevier B.V. All rights reserved.

Clinical signs of early osteoarthritis: reproducibility and relation to x ray changes in 541 women in the general population.

PubMed Central

Hart, D J; Spector, T D; Brown, P; Wilson, P; Doyle, D V; Silman, A J

1991-01-01

The definition and classification of early clinically apparent osteoarthritis both in clinical situations and in epidemiological surveys remains a problem. Few data exist on the between-observer reproducibility of simple clinical methods of detecting hand and knee osteoarthritis in the population and their sensitivity and specificity as compared with radiography. Two observers first studied the reproducibility of a number of clinical signs in 41 middle aged women. Good rates of agreement were found for most of the clinical signs tested (kappa = 0.54-1.0). The more reproducible signs were then tested on a population of 541 women, aged 45-65, drawn from general practice, screening centres, and patients previously attending hospital for non-rheumatic problems. The major clinical signs used had a high specificity (87-99%) and lower sensitivity (20-49%) when compared with radiographs graded on the Kellgren and Lawrence scale (2+ = positive). When analysis was restricted to symptomatic radiographic osteoarthritis, levels of sensitivity were increased and specificity was lowered. These data show that certain physical signs of osteoarthritis are reproducible and may be used to identify clinical disease. They are not a substitute for radiographs, however, if radiographic change is regarded as the 'gold standard' of diagnosis. As the clinical signs tested seemed specific for osteoarthritis they may be of value in screening populations for clinical disease. PMID:1877852

Context-sensitive patch histograms for detecting rare events in histopathological data

NASA Astrophysics Data System (ADS)

Diaz, Kristians; Baust, Maximilian; Navab, Nassir

2017-03-01

Assessment of histopathological data is not only difficult due to its varying appearance, e.g. caused by staining artifacts, but also due to its sheer size: Common whole slice images feature a resolution of 6000x4000 pixels. Therefore, finding rare events in such data sets is a challenging and tedious task and developing sophisticated computerized tools is not easy, especially when no or little training data is available. In this work, we propose learning-free yet effective approach based on context sensitive patch-histograms in order to find extramedullary hematopoiesis events in Hematoxylin-Eosin-stained images. When combined with a simple nucleus detector, one can achieve performance levels in terms of sensitivity 0.7146, specificity 0.8476 and accuracy 0.8353 which are very well comparable to a recently published approach based on random forests.

SPR based hybrid electro-optic biosensor for β-lactam antibiotics determination in water

NASA Astrophysics Data System (ADS)

Galatus, Ramona; Feier, Bogdan; Cristea, Cecilia; Cennamo, Nunzio; Zeni, Luigi

2017-09-01

The present work aims to provide a hybrid platform capable of complementary and sensitive detection of β-lactam antibiotics, ampicillin in particular. The use of an aptamer specific to ampicillin assures good selectivity and sensitivity for the detection of ampicillin from different matrice. This new approach is dedicated for a portable, remote sensing platform based on low-cost, small size and low-power consumption solution. The simple experimental hybrid platform integrates the results from the D-shape surface plasmon resonance plastic optical fiber (SPR-POF) and from the electrochemical (bio)sensor, for the analysis of ampicillin, delivering sensitive and reliable results. The SPR-POF already used in many previous applications is embedded in a new experimental setup with fluorescent fibers emitters, for broadband wavelength analysis, low-power consumption and low-heating capabilities of the sensing platform.

Systematic review and meta-analysis of the performance of clinical risk assessment instruments for screening for osteoporosis or low bone density

PubMed Central

Edwards, D. L.; Saleh, A. A.; Greenspan, S. L.

2015-01-01

Summary We performed a systematic review and meta-analysis of the performance of clinical risk assessment instruments for screening for DXA-determined osteoporosis or low bone density. Commonly evaluated risk instruments showed high sensitivity approaching or exceeding 90 % at particular thresholds within various populations but low specificity at thresholds required for high sensitivity. Simpler instruments, such as OST, generally performed as well as or better than more complex instruments. Introduction The purpose of the study is to systematically review the performance of clinical risk assessment instruments for screening for dual-energy X-ray absorptiometry (DXA)-determined osteoporosis or low bone density. Methods Systematic review and meta-analysis were performed. Multiple literature sources were searched, and data extracted and analyzed from included references. Results One hundred eight references met inclusion criteria. Studies assessed many instruments in 34 countries, most commonly the Osteoporosis Self-Assessment Tool (OST), the Simple Calculated Osteoporosis Risk Estimation (SCORE) instrument, the Osteoporosis Self-Assessment Tool for Asians (OSTA), the Osteoporosis Risk Assessment Instrument (ORAI), and body weight criteria. Meta-analyses of studies evaluating OST using a cutoff threshold of <1 to identify US postmenopausal women with osteoporosis at the femoral neck provided summary sensitivity and specificity estimates of 89 % (95%CI 82–96 %) and 41 % (95%CI 23–59 %), respectively. Meta-analyses of studies evaluating OST using a cutoff threshold of 3 to identify US men with osteoporosis at the femoral neck, total hip, or lumbar spine provided summary sensitivity and specificity estimates of 88 % (95%CI 79–97 %) and 55 % (95%CI 42–68 %), respectively. Frequently evaluated instruments each had thresholds and populations for which sensitivity for osteoporosis or low bone mass detection approached or exceeded 90 % but always with a trade-off of relatively low specificity. Conclusions Commonly evaluated clinical risk assessment instruments each showed high sensitivity approaching or exceeding 90 % for identifying individuals with DXA-determined osteoporosis or low BMD at certain thresholds in different populations but low specificity at thresholds required for high sensitivity. Simpler instruments, such as OST, generally performed as well as or better than more complex instruments. PMID:25644147

Intimate partner violence (IPV): The validity of an IPV screening instrument utilized among pregnant women in Tanzania and Vietnam

PubMed Central

Rasch, Vibeke; Van, Toan Ngo; Nguyen, Hanh Thi Thuy; Manongi, Rachel; Mushi, Declare; Meyrowitsch, Dan W.; Gammeltoft, Tine; Wu, Chun Sen

2018-01-01

Background Intimate partner violence (IPV) is a global problem that affects one-third of all women. The present study aims to develop and determine the validity of a screening instrument for the detection of IPV in pregnant women in Tanzania and Vietnam and to determine the minimum number of questions needed to identify IPV. Method An IPV screening instrument based on eight questions was tested on 1,116 Tanzanian and 1,309 Vietnamese women who attended antenatal care before 24 gestational weeks. The women were re-interviewed during their 30th-34th gestational week where the World Health Organization (WHO) IPV questionnaire was used as the gold standard. In all, 255 combinations of eight different questions were first tested on the Tanzanian study population where sensitivity, specificity, positive predictive value, negative predictive value and accuracy were calculated. In the evaluation of the performance of the question combinations, different IPV types and the frequency of abusive acts were considered. The question combinations that performed best in Tanzania were subsequently evaluated in the Vietnamese study population. Results In Tanzania, a combination of three selected questions including one question on emotional IPV, one on physical IPV and one on sexual IPV was found to be most effective in identifying women who are exposed to at least one type of IPV during pregnancy (sensitivity = .80; specificity = .74). The performance of the identified combination was slightly less effective in Vietnam (sensitivity = .74; specificity = .68). Focusing on different IPV types, the best performance was found for exposure to physical IPV in both Tanzania (sensitivity = .93; specificity = .70) and Vietnam (sensitivity = .96; specificity = .55). In both countries, the sensitivity increased with the frequency of abuse whereas the specificity decreased. Conclusion By asking pregnant women three simple questions we were able to identify women who were exposed to IPV during pregnancy in two different countries. The question combination performed best in assessing physical IPV where it identified 93% and 96% of Vietnamese and Tanzanian women, respectively, who were exposed to physical IPV. PMID:29389954

Waist-to-Height Ratio: a simple, effective and practical screening tool for childhood obesity and metabolic syndrome.

PubMed

Zhou, Dan; Yang, Min; Yuan, Zhe-Ping; Zhang, Dan-Dan; Liang, Li; Wang, Chun-Lin; Zhang, Shuai; Zhu, Hong-Hong; Lai, Mao-De; Zhu, Yi-Min

2014-10-01

This study aimed to evaluate the diagnostic value of Waist-to-Height Ratio in early detection of obesity and metabolic syndrome in Chinese children and adolescents. A cross-sectional study was conducted in six cities in China in 2010 with 16,914 children and adolescents aged 7-17 years. Participants were randomly divided into the training and testing sets. Diagnostic values were estimated using sensitivity, specificity and areas under receiver operating characteristic curves. The coefficients of variation of Waist-to-Height Ratio among age groups were lower than that of body mass index and waist circumstance. The area under receiver operating characteristic curve of Waist-to-Height Ratio was 0.968 in boys and 0.949 in girls for general obesity evaluation, and 0.983 in boys and 0.984 in girls for central obesity. The optimal cut-offs of Waist-to-Height Ratio were 0.47 in boys and 0.45 in girls in the training set and validated in the testing set. For metabolic syndrome evaluation, the sensitivity and specificity were 0.858 and 0.825 in boys, 0.864 and 0.812 in girls under the suggested cut-offs. Waist-to-Height Ratio was a simple, effective and practical tool for mass screening childhood obesity and metabolic syndrome in China. It will have potential values in public health practice. Copyright © 2014 Elsevier Inc. All rights reserved.

Approaching near real-time biosensing: microfluidic microsphere based biosensor for real-time analyte detection.

PubMed

Cohen, Noa; Sabhachandani, Pooja; Golberg, Alexander; Konry, Tania

2015-04-15

In this study we describe a simple lab-on-a-chip (LOC) biosensor approach utilizing well mixed microfluidic device and a microsphere-based assay capable of performing near real-time diagnostics of clinically relevant analytes such cytokines and antibodies. We were able to overcome the adsorption kinetics reaction rate-limiting mechanism, which is diffusion-controlled in standard immunoassays, by introducing the microsphere-based assay into well-mixed yet simple microfluidic device with turbulent flow profiles in the reaction regions. The integrated microsphere-based LOC device performs dynamic detection of the analyte in minimal amount of biological specimen by continuously sampling micro-liter volumes of sample per minute to detect dynamic changes in target analyte concentration. Furthermore we developed a mathematical model for the well-mixed reaction to describe the near real time detection mechanism observed in the developed LOC method. To demonstrate the specificity and sensitivity of the developed real time monitoring LOC approach, we applied the device for clinically relevant analytes: Tumor Necrosis Factor (TNF)-α cytokine and its clinically used inhibitor, anti-TNF-α antibody. Based on the reported results herein, the developed LOC device provides continuous sensitive and specific near real-time monitoring method for analytes such as cytokines and antibodies, reduces reagent volumes by nearly three orders of magnitude as well as eliminates the washing steps required by standard immunoassays. Copyright © 2014 Elsevier B.V. All rights reserved.

The characterization of small hypoattenuating renal masses on contrast-enhanced CT☆

PubMed Central

Patel, Neesha S.; Poder, Liina; Wang, Zhen J.; Yeh, Benjamin M.; Qayyum, Aliya; Jin, Hua; Coakley, Fergus V.

2011-01-01

Purpose To determine if small hypoattenuating renal masses can be characterized as simple cysts or renal cell carcinomas on contrast-enhanced computed tomography (CT). Materials and methods We retrospectively identified 20 small (≤1.5 cm) hypoattenuating renal masses seen on contrast enhanced CT, consisting of 14 simple cysts and six renal cell carcinomas. Three independent readers recorded subjective visual impression (five-point scale from 1=definitely fluid to 5=definitely solid), CT attenuation, border (well circumscribed or ill defined), and shape (ovoid or irregular) for each lesion. Results The overall area under the receiver operator characteristic curves for subjective visual impression, CT attenuation, border, and shape were 0.97, 0.82, 0.59, and 0.55, respectively. Using dichotomized ratings (1–2=cyst and 3–5=carcinoma), subjective impression had a sensitivity and specificity of 100% and 79–100%, respectively, for the diagnosis of renal cell carcinoma. Using a threshold of 50 Hounsfield Units (HU) or more, CT attenuation had a sensitivity and specificity of 100% and 43–64%, respectively. Conclusion Small hypoattenuating renal masses can be characterized with reasonable accuracy by subjective impression and CT attenuation; lesions that appear solid on visual inspection or have an attenuation value of 50 HU or more are likely to be renal cell carcinoma. © 2009 Elsevier Inc. All rights reserved. PMID:19559352

Evaluation of latex agglutination test (KAtex) for early diagnosis of kala-azar.

PubMed

Ahsan, M M; Islam, M N; Mollah, A H; Hoque, M A; Hossain, M A; Begum, Z; Islam, M T

2010-07-01

Kala-azar is one of the major public health problem in Bangladesh. But the diagnosis of the problem often is difficult, unusual and time consuming, a simple, noninvasive, easy to perform, reliable and rapid diagnostic test has been a long-felt need of the clinicians. Therefore, the present study was conducted to see the sensitivity and specificity of Latex Agglutination test (KAtex) to detect leishmanial antigen from urine of kala-azar cases. The study was carried out in the department of Paediatrics, Mymensingh Medical College and Hospital, Bangladesh during July to December, 2008. A total of 100 urine samples were collected of which 50 were confirmed kala-azar cases and 50 were age and sex matched controls. Out of 50 kala-azar cases 47 showed positive result of KAtex. The test was also positive in 01 out of 30 healthy controls. None of the febrile controls was positive by KAtex. The sensitivity, specificity, positive predictive value and negative predictive value of the test using presence of LD bodies in splenic and/or bone marrow aspirate as gold standard were 94%, 98%, 97.91% and 94.23% respectively. KAtex is simple, noninvasive, easy to perform, rapid and reliable test for diagnosing kala-azar in endemic area and useful for small, less equipped laboratories as well as for the laboratories with better facilities.

[Value of using polyethylene glycol in the indirect antiglobulin test with erythrocytes].

PubMed

Michalewska, B; Walewska, I; Seyfriedowa, H; Kuśnierz-Alejska, G

1991-01-01

A series of comparative investigations was carried out for establishing the value of the indirect antiglobulin test (IAT) in its first phase. The results showed that PEG, in relation to NaCl solution of low ionic strength, increased the reactivity of various antibodies of different specificity present in 72 studied sera. A significant superiority of IAT-PEG to IAT-BISS was noted in 45.8% of these sera. In search for antibodies in sera of 1160 patients IAT-PEG detected 7 antibodies not reacting in the IAT-LISS, and 5 of them had Rh system specificity, one was anti-K and one anti-Jka. Although the IAT-PEG was more sensitive than IAT-LISS in the detection of anti-Rh antibodies, it was less sensitive in this range than the enzymatic LEN test with which not only 5 of these antibodies were demonstrated but which detected also 8 antibodies not demonstrated in IAT-PEG or IAT-LISS. All 5 antibodies not detected by the IAT-PEG but demonstrated in the IAT-LISS were specific for the Lewis system. The per cent of reactions regarded as non-specific in the IAT-PEG was 1.3%. The IAT-PEG modification may be recommended as a sensitive, simple and specific method extending the possibilities of immunohematological diagnosis, especially in cases of post-transfusion reactions and in difficulties of interpretation connected with the occurrence of weakly positive reactions in the IAT-LISS.

Loop-mediated isothermal amplification (LAMP) assays for the species-specific detection of Eimeria that infect chickens

PubMed Central

2011-01-01

Background Eimeria parasites can cause the disease coccidiosis in poultry and even subclinical infection can incur economic loss. Diagnosis of infection predominantly relies on traditional techniques including lesion scoring and faecal microscopy despite the availability of sensitive molecular assays, largely due to cost and the requirement for specialist equipment. Despite longstanding proven efficacy these traditional techniques demand time and expertise, can be highly subjective and may under-diagnose subclinical disease. Recognition of the tight economic margins prevailing in modern poultry production and the impact of avian coccidiosis on poverty in many parts of the world has highlighted a requirement for a panel of straightforward and sensitive, but cost-effective, Eimeria species-specific diagnostic assays. Results Loop-mediated isothermal amplification (LAMP) is an uncomplicated, quick and relatively inexpensive diagnostic tool. In this study we have developed a panel of species-specific LAMP assays targeting the seven Eimeria species that infect the chicken. Each assay has been shown to be genuinely species-specific with the capacity to detect between one and ten eimerian genomes, equivalent to less than a single mature schizont. Development of a simple protocol for template DNA preparation from tissue collected post mortem with no requirement for specialist laboratory equipment supports the use of these assays in routine diagnosis of eimerian infection. Preliminary field testing supports this hypothesis. Conclusions Development of a panel of sensitive species-specific LAMP assays introduces a valuable new cost-effective tool for use in poultry husbandry. PMID:22053893

Efficient molecular screening of Lynch syndrome by specific 3' promoter methylation of the MLH1 or BRAF mutation in colorectal cancer with high-frequency microsatellite instability.

PubMed

Nakagawa, Hitoshi; Nagasaka, Takeshi; Cullings, Harry M; Notohara, Kenji; Hoshijima, Naoko; Young, Joanne; Lynch, Henry T; Tanaka, Noriaki; Matsubara, Nagahide

2009-06-01

It is sometimes difficult to diagnose Lynch syndrome by the simple but strict clinical criteria, or even by the definitive genetic testing for causative germline mutation of mismatch repair genes. Thus, some practical and efficient screening strategy to select highly possible Lynch syndrome patients is exceedingly desirable. We performed a comprehensive study to evaluate the methylation status of whole MLH1 promoter region by direct bisulfite sequencing of the entire MLH1 promoter regions on Lynch and non-Lynch colorectal cancers (CRCs). Then, we established a convenient assay to detect methylation in key CpG islands responsible for the silencing of MLH1 expression. We studied the methylation status of MLH1 as well as the CpG island methylator phenotype (CIMP) and immunohistochemical analysis of mismatch repair proteins on 16 cases of Lynch CRC and 19 cases of sporadic CRCs with high-frequency microsatellite instability (MSI-H). Sensitivity to detect Lynch syndrome by MLH1 (CCAAT) methylation was 88% and the specificity was 84%. Positive likelihood ratio (PLR) was 5.5 and negative likelihood ratio (NLR) was 0.15. Sensitivity by mutational analysis of BRAF was 100%, specificity was 84%, PLR was 6.3 and NLR was zero. By CIMP analysis; sensitivity was 88%, specificity was 79%, PLR was 4.2, and NLR was 0.16. BRAF mutation or MLH1 methylation analysis combined with MSI testing could be a good alternative to screen Lynch syndrome patients in a cost effective manner. Although the assay for CIMP status also showed acceptable sensitivity and specificity, it may not be practical because of its rather complicated assay.

Distinguishing Secondary Dengue Virus Infection From Zika Virus Infection With Previous Dengue by a Combination of 3 Simple Serological Tests.

PubMed

Tsai, Wen-Yang; Youn, Han Ha; Brites, Carlos; Tsai, Jih-Jin; Tyson, Jasmine; Pedroso, Celia; Drexler, Jan Felix; Stone, Mars; Simmons, Graham; Busch, Michael P; Lanteri, Marion; Stramer, Susan L; Balmaseda, Angel; Harris, Eva; Wang, Wei-Kung

2017-11-13

The explosive spread of Zika virus (ZIKV) and associated microcephaly present an urgent need for sensitive and specific serodiagnostic tests, particularly for pregnant women in dengue virus (DENV)-endemic regions. Recent reports of enhanced ZIKV replication by dengue-immune sera have raised concerns about the role of previous DENV infection on the risk and severity of microcephaly and other ZIKV complications. Enzyme-linked immunosorbent assays (ELISAs) based on ZIKV and DENV nonstructural protein 1 (NS1) were established to test acute, convalescent phase, and post-convalescent phase serum/plasma samples from reverse-transcription polymerase chain reaction-confirmed cases including 20 primary ZIKV, 25 ZIKV with previous DENV, 58 secondary DENV, and 16 primary DENV1 infections. ZIKV-NS1 immunoglobulin M (IgM) and immunoglobulin G (IgG) ELISAs combined can detect ZIKV infection with a sensitivity of 95% and specificity of 66.7%. The ZIKV-NS1 IgG cross-reactivity by samples from secondary DENV infection cases ranged from 66.7% to 28.1% (within 1 month to 1-2 years post-illness, respectively). Addition of DENV1-NS1 IgG ELISA can distinguish primary ZIKV infection; the ratio of absorbance of ZIKV-NS1 to DENV1-NS1 IgG ELISA can distinguish ZIKV with previous DENV and secondary DENV infections with a sensitivity of 87.5% and specificity of 81.3%. These findings were supported by analysis of sequential samples. An algorithm for ZIKV serodiagnosis based on 3 simple ELISAs is proposed to distinguish primary ZIKV, ZIKV with previous DENV, and secondary DENV infections; this could be applied to serodiagnosis for ZIKV, serosurveillance, and monitoring ZIKV infection during pregnancy to understand the epidemiology, pathogenesis, and complications of ZIKV in dengue-endemic regions. © The Author 2017. Published by Oxford University Press for the Infectious Diseases Society of America. All rights reserved. For permissions, e-mail: journals.permissions@oup.com.

Reliability of Waveform Analysis as an Adjunct to Loss of Resistance for Thoracic Epidural Blocks.

PubMed

Leurcharusmee, Prangmalee; Arnuntasupakul, Vanlapa; Chora De La Garza, Daniel; Vijitpavan, Amorn; Ah-Kye, Sonia; Saelao, Abhidej; Tiyaprasertkul, Worakamol; Finlayson, Roderick J; Tran, De Q H

2015-01-01

The epidural space is most commonly identified with loss of resistance (LOR). Although sensitive, LOR lacks specificity, as cysts in interspinous ligaments, gaps in ligamentum flavum, paravertebral muscles, thoracic paravertebral spaces, and intermuscular planes can yield nonepidural LOR. Epidural waveform analysis (EWA) provides a simple confirmatory adjunct for LOR. When the needle is correctly positioned inside the epidural space, measurement of the pressure at its tip results in a pulsatile waveform. In this observational study, we set out to assess the sensitivity, specificity, as well as positive and negative predictive values of EWA for thoracic epidural blocks. We enrolled a convenience sample of 160 patients undergoing thoracic epidural blocks for thoracic surgery, abdominal surgery, or rib fractures. The choice of patient position (sitting or lateral decubitus), approach (midline or paramedian), and LOR medium (air or normal saline) was left to the operator (attending anesthesiologist, fellow, or resident). After obtaining a satisfactory LOR, the operator injected 5 mL of normal saline through the epidural needle. A sterile tubing, connected to a pressure transducer, was attached to the needle to measure the pressure at the needle tip. A 4-mL bolus of lidocaine 2% with epinephrine 5 μg/mL was then administered and, after 10 minutes, the patient was assessed for sensory blockade to ice. The failure rate (incorrect identification of the epidural space with LOR) was 23.1%. Of these 37 failed epidural blocks, 27 provided no sensory anesthesia at 10 minutes. In 10 subjects, the operator was unable to thread the catheter through the needle. When compared with the ice test, the sensitivity, specificity, and positive and negative predictive values of EWA were 91.1%, 83.8%, 94.9%, and 73.8%, respectively. Epidural waveform analysis (with pressure transduction through the needle) provides a simple adjunct to LOR for thoracic epidural blocks. Although its use was devoid of complications, further confirmatory studies are required before its routine implementation in clinical practice.

[Validation of taking arterial pulse in Primary Care for the detection of atrial fibrillation and other cardiac rhythm disorders in patients over 65 years old].

PubMed

Pérula-de Torres, L A; González-Blanco V, V; Luque-Montilla, R; Martín-Rioboó, E; Martínez-Adell, M A; Ruiz-de Castroviejo, J

2017-09-01

Atrial fibrillation (AF) is the most frequent arrhythmia in clinical practice and has important prognostic implications. The objective of this study was to demonstrate the validity and the reliability of taking the arterial pulse (TAP) in patients over 65 years for detecting in AF and other rhythm disorders. A descriptive, observational, multicentre study to validate a diagnostic test within in a controlled clinical trial. 39 Primary Care Centres in the Spanish National Health Service. A total of 318 physicians and nurses took part in the analysis of validity, and 166 of them took part in the analysis of reliability. The professionals were previously called to a meeting in which they took the arterial pulses, and were given 4 ECGs to interpret. The participants TAP of 864 patients followed by an ECG to confirm the cardiac rhythm. Sensitivity, specificity and predictive values were estimated to assess the criterial validity and the simple concordance index to check reproducibility. The sensitivity of pulse measurement for detecting AF detection was 99.4% (95% CI: 97.9-100.0), with a specificity of 30.7% (95% CI: 26.1-35.3), a positive predictive value of 36.6% (95% CI 32.0-41.2), and negative predictive value of 99.2% (97.3-100.0). The simple concordance between the researchers and the cardiologist for the ECG diagnosis of AF ranged between 84.9% and 91.6%. The TAP has a high sensitivity but a low specificity to detect AF. It is a reliable test for the opportunistic screening of arrhythmias in patients aged over 65 years. Copyright © 2016 Sociedad Española de Médicos de Atención Primaria (SEMERGEN). Publicado por Elsevier España, S.L.U. All rights reserved.

IOTA Simple Rules in Differentiating between Benign and Malignant Adnexal Masses by Non-expert Examiners.

PubMed

Tinnangwattana, Dangcheewan; Vichak-Ururote, Linlada; Tontivuthikul, Paponrad; Charoenratana, Cholaros; Lerthiranwong, Thitikarn; Tongsong, Theera

2015-01-01

To evaluate the diagnostic performance of IOTA simple rules in predicting malignant adnexal tumors by non-expert examiners. Five obstetric/gynecologic residents, who had never performed gynecologic ultrasound examination by themselves before, were trained for IOTA simple rules by an experienced examiner. One trained resident performed ultrasound examinations including IOTA simple rules on 100 women, who were scheduled for surgery due to ovarian masses, within 24 hours of surgery. The gold standard diagnosis was based on pathological or operative findings. The five-trained residents performed IOTA simple rules on 30 patients for evaluation of inter-observer variability. A total of 100 patients underwent ultrasound examination for the IOTA simple rules. Of them, IOTA simple rules could be applied in 94 (94%) masses including 71 (71.0%) benign masses and 29 (29.0%) malignant masses. The diagnostic performance of IOTA simple rules showed sensitivity of 89.3% (95%CI, 77.8%; 100.7%), specificity 83.3% (95%CI, 74.3%; 92.3%). Inter-observer variability was analyzed using Cohen's kappa coefficient. Kappa indices of the four pairs of raters are 0.713-0.884 (0.722, 0.827, 0.713, and 0.884). IOTA simple rules have high diagnostic performance in discriminating adnexal masses even when are applied by non-expert sonographers, though a training course may be required. Nevertheless, they should be further tested by a greater number of general practitioners before widely use.

Strategies to diagnose ovarian cancer: new evidence from phase 3 of the multicentre international IOTA study

PubMed Central

Testa, A; Kaijser, J; Wynants, L; Fischerova, D; Van Holsbeke, C; Franchi, D; Savelli, L; Epstein, E; Czekierdowski, A; Guerriero, S; Fruscio, R; Leone, F P G; Vergote, I; Bourne, T; Valentin, L; Van Calster, B; Timmerman, D

2014-01-01

Background: To compare different ultrasound-based international ovarian tumour analysis (IOTA) strategies and risk of malignancy index (RMI) for ovarian cancer diagnosis using a meta-analysis approach of centre-specific data from IOTA3. Methods: This prospective multicentre diagnostic accuracy study included 2403 patients with 1423 benign and 980 malignant adnexal masses from 2009 until 2012. All patients underwent standardised transvaginal ultrasonography. Test performance of RMI, subjective assessment (SA) of ultrasound findings, two IOTA risk models (LR1 and LR2), and strategies involving combinations of IOTA simple rules (SRs), simple descriptors (SDs) and LR2 with and without SA was estimated using a meta-analysis approach. Reference standard was histology after surgery. Results: The areas under the receiver operator characteristic curves of LR1, LR2, SA and RMI were 0.930 (0.917–0.942), 0.918 (0.905–0.930), 0.914 (0.886–0.936) and 0.875 (0.853–0.894). Diagnostic one-step and two-step strategies using LR1, LR2, SR and SD achieved summary estimates for sensitivity 90–96%, specificity 74–79% and diagnostic odds ratio (DOR) 32.8–50.5. Adding SA when IOTA methods yielded equivocal results improved performance (DOR 57.6–75.7). Risk of Malignancy Index had sensitivity 67%, specificity 91% and DOR 17.5. Conclusions: This study shows all IOTA strategies had excellent diagnostic performance in comparison with RMI. The IOTA strategy chosen may be determined by clinical preference. PMID:24937676

Sensitive and Specific Biomimetic Lipid Coated Microfluidics to Isolate Viable Circulating Tumor Cells and Microemboli for Cancer Detection.

PubMed

Chen, Jia-Yang; Tsai, Wen-Sy; Shao, Hung-Jen; Wu, Jen-Chia; Lai, Jr-Ming; Lu, Si-Hong; Hung, Tsung-Fu; Yang, Chih-Tsung; Wu, Liang-Chun; Chen, Jinn-Shiun; Lee, Wen-Hwa; Chang, Ying-Chih

2016-01-01

Here we presented a simple and effective membrane mimetic microfluidic device with antibody conjugated supported lipid bilayer (SLB) "smart coating" to capture viable circulating tumor cells (CTCs) and circulating tumor microemboli (CTM) directly from whole blood of all stage clinical cancer patients. The non-covalently bound SLB was able to promote dynamic clustering of lipid-tethered antibodies to CTC antigens and minimized non-specific blood cells retention through its non-fouling nature. A gentle flow further flushed away loosely-bound blood cells to achieve high purity of CTCs, and a stream of air foam injected disintegrate the SLB assemblies to release intact and viable CTCs from the chip. Human blood spiked cancer cell line test showed the ~95% overall efficiency to recover both CTCs and CTMs. Live/dead assay showed that at least 86% of recovered cells maintain viability. By using 2 mL of peripheral blood, the CTCs and CTMs counts of 63 healthy and colorectal cancer donors were positively correlated with the cancer progression. In summary, a simple and effective strategy utilizing biomimetic principle was developed to retrieve viable CTCs for enumeration, molecular analysis, as well as ex vivo culture over weeks. Due to the high sensitivity and specificity, it is the first time to show the high detection rates and quantity of CTCs in non-metastatic cancer patients. This work offers the values in both early cancer detection and prognosis of CTC and provides an accurate non-invasive strategy for routine clinical investigation on CTCs.

A label-free colorimetric aptasensor for simple, sensitive and selective detection of Pt (II) based on platinum (II)-oligonucleotide coordination induced gold nanoparticles aggregation.

PubMed

Fan, Daoqing; Zhai, Qingfeng; Zhou, Weijun; Zhu, Xiaoqing; Wang, Erkang; Dong, Shaojun

2016-11-15

Herein, a gold nanoparticles (AuNPs) based label-free colorimetric aptasensor for simple, sensitive and selective detection of Pt (II) was constructed for the first time. Four bases (G-G mismatch) mismatched streptavidin aptamer (MSAA) was used to protect AuNPs from salt-induced aggregation and recognize Pt (II) specifically. Only in the presence of Pt (II), coordination occurs between G-G bases and Pt (II), leading to the activation of streptavidin aptamer. Streptavidin coated magnetic beads (MBs) were used as separation agent to separate Pt (II)-coordinated MSAA. The residual less amount of MSAA could not efficiently protect AuNPs anymore and aggregation of AuNPs will produce a colorimetric product. With the addition of Pt (II), a pale purple-to-blue color variation could be observed by the naked eye. A detection limit of 150nM and a linear range from 0.6μM to 12.5μM for Pt (II) could be achieved without any amplification. Copyright © 2016 Elsevier B.V. All rights reserved.

Evaluation of Different PCR-Based Assays and LAMP Method for Rapid Detection of Phytophthora infestans by Targeting the Ypt1 Gene

PubMed Central

Khan, Mehran; Li, Benjin; Jiang, Yue; Weng, Qiyong; Chen, Qinghe

2017-01-01

Late blight, caused by the oomycete Phytophthora infestans, is one of the most devastating diseases affecting potato and tomato worldwide. Early diagnosis of the P. infestans pathogen causing late blight should be the top priority for addressing disease epidemics and management. In this study, we performed a loop-mediated isothermal amplification (LAMP) assay, conventional polymerase chain reaction (PCR), nested PCR, and real-time PCR to verify and compare the sensitivity and specificity of the reaction based on the Ypt1 (Ras-related protein) gene of P. infestans. In comparison with the PCR-based assays, the LAMP technique led to higher specificity and sensitivity, using uncomplicated equipment with an equivalent time frame. All 43 P. infestans isolates, yielded positive detection results using LAMP assay showing no cross reaction with other Phytophthora spp., oomycetes or fungal pathogens. The LAMP assay yielded the lowest detectable DNA concentration (1.28 × 10-4 ng μL-1), being 10 times more sensitive than nested PCR (1.28 × 10-3 ng μL-1), 100 times more sensitive than real-time PCR (1.28 × 10-2 ng μL-1) and 103 times more sensitive than the conventional PCR assay (1.28 × 10-1 ng μL-1). In the field experiment, the LAMP assay outperformed the other tests by amplifying only diseased tissues (leaf and stem), and showing no positive reaction in healthy tissues. Overall, the LAMP assay developed in this study provides a specific, sensitive, simple, and effective visual method for detection of the P. infestans pathogen, and is therefore suitable for application in early prediction of the disease to reduce the risk of epidemics. PMID:29051751

Evaluation of Different PCR-Based Assays and LAMP Method for Rapid Detection of Phytophthora infestans by Targeting the Ypt1 Gene.

PubMed

Khan, Mehran; Li, Benjin; Jiang, Yue; Weng, Qiyong; Chen, Qinghe

2017-01-01

Late blight, caused by the oomycete Phytophthora infestans , is one of the most devastating diseases affecting potato and tomato worldwide. Early diagnosis of the P. infestans pathogen causing late blight should be the top priority for addressing disease epidemics and management. In this study, we performed a loop-mediated isothermal amplification (LAMP) assay, conventional polymerase chain reaction (PCR), nested PCR, and real-time PCR to verify and compare the sensitivity and specificity of the reaction based on the Ypt1 (Ras-related protein) gene of P. infestans. In comparison with the PCR-based assays, the LAMP technique led to higher specificity and sensitivity, using uncomplicated equipment with an equivalent time frame. All 43 P. infestans isolates, yielded positive detection results using LAMP assay showing no cross reaction with other Phytophthora spp., oomycetes or fungal pathogens. The LAMP assay yielded the lowest detectable DNA concentration (1.28 × 10 -4 ng μL -1 ), being 10 times more sensitive than nested PCR (1.28 × 10 -3 ng μL -1 ), 100 times more sensitive than real-time PCR (1.28 × 10 -2 ng μL -1 ) and 10 3 times more sensitive than the conventional PCR assay (1.28 × 10 -1 ng μL -1 ). In the field experiment, the LAMP assay outperformed the other tests by amplifying only diseased tissues (leaf and stem), and showing no positive reaction in healthy tissues. Overall, the LAMP assay developed in this study provides a specific, sensitive, simple, and effective visual method for detection of the P. infestans pathogen, and is therefore suitable for application in early prediction of the disease to reduce the risk of epidemics.

Role of imprint cytology in intra operative diagnosis of thyroid lesions.

PubMed

Anila, K R; Krishna, G

2014-07-01

Intra-operative imprint cytology is an important diagnostic modality in the diagnosis of thyroid lesions. A correct intra-operative diagnosis helps eliminate the need for second surgery. To study diagnostic accuracy of imprint cytology and to compare the imprint cytology results with that of the corresponding paraffin section diagnosis in thyroidectomy cases. This is a prospective study of 84 patients who have undergone thyroidectomies over a period of one year at the Department of Surgery, Thiruvananthapuram, Kerala, India. The intraoperative imprint cytology smears were stained by Papanicolaou method. The imprint cytology interpretation was later compared with the paraffin section diagnosis. Of the 84 patients using haematoxylin and eosin stained histopathology sections as the gold standard, the diagnostic sensitivity of imprint cytology was 75% and specificity was 100%. Positive predictive value was 100%. Negative predictive value was 98.74%. Imprint cytology has high sensitivity and specificity in diagnosing lesions of the thyroid. The problems faced were in diagnosing follicular carcinomas and differentiating low grade lymphoma from lymphocytic thyroiditis. Imprint cytology is a simple, reliable diagnostic technique. It has high sensitivity and specificity in intra-operative diagnosis of lesions of thyroid. In spite of the advent of newer diagnostic modalities like frozen sections, imprint cytology still holds its unique position in the current perspective.

A Comparison between Decision Tree and Random Forest in Determining the Risk Factors Associated with Type 2 Diabetes.

PubMed

Esmaily, Habibollah; Tayefi, Maryam; Doosti, Hassan; Ghayour-Mobarhan, Majid; Nezami, Hossein; Amirabadizadeh, Alireza

2018-04-24

We aimed to identify the associated risk factors of type 2 diabetes mellitus (T2DM) using data mining approach, decision tree and random forest techniques using the Mashhad Stroke and Heart Atherosclerotic Disorders (MASHAD) Study program. A cross-sectional study. The MASHAD study started in 2010 and will continue until 2020. Two data mining tools, namely decision trees, and random forests, are used for predicting T2DM when some other characteristics are observed on 9528 subjects recruited from MASHAD database. This paper makes a comparison between these two models in terms of accuracy, sensitivity, specificity and the area under ROC curve. The prevalence rate of T2DM was 14% among these subjects. The decision tree model has 64.9% accuracy, 64.5% sensitivity, 66.8% specificity, and area under the ROC curve measuring 68.6%, while the random forest model has 71.1% accuracy, 71.3% sensitivity, 69.9% specificity, and area under the ROC curve measuring 77.3% respectively. The random forest model, when used with demographic, clinical, and anthropometric and biochemical measurements, can provide a simple tool to identify associated risk factors for type 2 diabetes. Such identification can substantially use for managing the health policy to reduce the number of subjects with T2DM .

Evaluation of quantitative image analysis criteria for the high-resolution microendoscopic detection of neoplasia in Barrett's esophagus

NASA Astrophysics Data System (ADS)

Muldoon, Timothy J.; Thekkek, Nadhi; Roblyer, Darren; Maru, Dipen; Harpaz, Noam; Potack, Jonathan; Anandasabapathy, Sharmila; Richards-Kortum, Rebecca

2010-03-01

Early detection of neoplasia in patients with Barrett's esophagus is essential to improve outcomes. The aim of this ex vivo study was to evaluate the ability of high-resolution microendoscopic imaging and quantitative image analysis to identify neoplastic lesions in patients with Barrett's esophagus. Nine patients with pathologically confirmed Barrett's esophagus underwent endoscopic examination with biopsies or endoscopic mucosal resection. Resected fresh tissue was imaged with fiber bundle microendoscopy; images were analyzed by visual interpretation or by quantitative image analysis to predict whether the imaged sites were non-neoplastic or neoplastic. The best performing pair of quantitative features were chosen based on their ability to correctly classify the data into the two groups. Predictions were compared to the gold standard of histopathology. Subjective analysis of the images by expert clinicians achieved average sensitivity and specificity of 87% and 61%, respectively. The best performing quantitative classification algorithm relied on two image textural features and achieved a sensitivity and specificity of 87% and 85%, respectively. This ex vivo pilot trial demonstrates that quantitative analysis of images obtained with a simple microendoscope system can distinguish neoplasia in Barrett's esophagus with good sensitivity and specificity when compared to histopathology and to subjective image interpretation.

Validity of the Hum Test, a Simple and Reliable Alternative to the Weber Test.

PubMed

Ahmed, Omar H; Gallant, Sara C; Ruiz, Ryan; Wang, Binhuan; Shapiro, William H; Voigt, Erich P

2018-06-01

To compare the diagnostic performance of the Hum Test against the Weber Test using pure tone audiometry (PTA) as the "gold standard" comparator. 29 participants with normal hearing of ages 18 to 35 without any history of hearing abnormalities or otologic conditions were enrolled. Subjects underwent three tests (Hum Test, Weber Test, and PTA) across two conditions: with an ear plug in one ear (side randomized) and without ear plugs. When examining the ability of the Hum Test to detect simulated conductive hearing loss (CHL), the test had a sensitivity of 89.7% and specificity of 100% with high pitched humming and 93.1% and 100%, respectively, with low pitched humming. The Weber Test had a sensitivity and specificity of 96.6% and 100%, respectively. McNemar's test demonstrated agreement between the Hum Test, performed with either high pitched ( P = .32) or low pitched ( P = .56) humming, and the Weber Test. Receiver operating characteristic (ROC) curves for the Hum Test (both high and low pitched) and Weber test were compared and demonstrated no statistically significant difference. The Hum Test is comparable to the Weber Test with regards to its sensitivity, specificity, and diagnostic accuracy in assessing new onset unilateral CHL in previously normal hearing subjects.

Pyrosequencing-based validation of a simple cell-suspension polymerase chain reaction assay for Campylobacter with application of high-processivity polymerase and novel internal amplification controls for rapid and specific detection.

PubMed

Oakley, Brian B; Line, J Eric; Berrang, Mark E; Johnson, Jessica M; Buhr, R Jeff; Cox, Nelson A; Hiett, Kelli L; Seal, Bruce S

2012-02-01

Although Campylobacter is an important food-borne human pathogen, there remains a lack of molecular diagnostic assays that are simple to use, cost-effective, and provide rapid results in research, clinical, or regulatory laboratories. Of the numerous Campylobacter assays that do exist, to our knowledge none has been empirically tested for specificity using high-throughput sequencing. Here we demonstrate the power of next-generation sequencing to determine the specificity of a widely cited Campylobacter-specific polymerase chain reaction (PCR) assay and describe a rapid method for direct cell suspension PCR to quickly and easily screen samples for Campylobacter. We present a specific protocol which eliminates the need for time-consuming and expensive genomic DNA extractions and, using a high-processivity polymerase, demonstrate conclusive screening of samples in <1 h. Pyrosequencing results show the assay to be extremely (>99%) sensitive, and spike-back experiments demonstrated a detection threshold of <10(2) CFU mL(-1). Additionally, we present 2 newly designed broad-range bacterial primer sets targeting the 23S rRNA gene that have wide applicability as internal amplification controls. Empirical testing of putative taxon-specific assays using high-throughput sequencing is an important validation step that is now financially feasible for research, regulatory, or clinical applications. Published by Elsevier Inc.

Quick and simple estimation of bacteria using a fluorescent paracetamol dimer-Au nanoparticle composite

NASA Astrophysics Data System (ADS)

Sahoo, Amaresh Kumar; Sharma, Shilpa; Chattopadhyay, Arun; Ghosh, Siddhartha Sankar

2012-02-01

Rapid, simple and sensitive detection of bacterial contamination is critical for safeguarding public health and the environment. Herein, we report an easy method of detection as well as enumeration of the bacterial cell number on the basis of fluorescence quenching of a non-antibacterial fluorescent nanocomposite, consisting of paracetamol dimer (PD) and Au nanoparticles (NPs), in the presence of bacteria. The composite was synthesized by reaction of paracetamol (p-hydroxyacetanilide) with HAuCl4. The Au NPs of the composite were characterized using UV-Vis spectroscopy, transmission electron microscopy (TEM), X-ray diffraction and selected area electron diffraction analysis. The paracetamol dimer in the composite showed emission peak at 435 nm when excited at 320 nm. The method successfully detected six bacterial strains with a sensitivity of 100 CFU mL-1. The Gram-positive and Gram-negative bacteria quenched the fluorescence of the composite differently, making it possible to distinguish between the two. The TEM analysis showed interaction of the composite with bacteria without any apparent damage to the bacteria. The chi-square test established the accuracy of the method. Quick, non-specific and highly sensitive detection of bacteria over a broad range of logarithmic dilutions within a short span of time demonstrates the potential of this method as an alternative to conventional methods.Rapid, simple and sensitive detection of bacterial contamination is critical for safeguarding public health and the environment. Herein, we report an easy method of detection as well as enumeration of the bacterial cell number on the basis of fluorescence quenching of a non-antibacterial fluorescent nanocomposite, consisting of paracetamol dimer (PD) and Au nanoparticles (NPs), in the presence of bacteria. The composite was synthesized by reaction of paracetamol (p-hydroxyacetanilide) with HAuCl4. The Au NPs of the composite were characterized using UV-Vis spectroscopy, transmission electron microscopy (TEM), X-ray diffraction and selected area electron diffraction analysis. The paracetamol dimer in the composite showed emission peak at 435 nm when excited at 320 nm. The method successfully detected six bacterial strains with a sensitivity of 100 CFU mL-1. The Gram-positive and Gram-negative bacteria quenched the fluorescence of the composite differently, making it possible to distinguish between the two. The TEM analysis showed interaction of the composite with bacteria without any apparent damage to the bacteria. The chi-square test established the accuracy of the method. Quick, non-specific and highly sensitive detection of bacteria over a broad range of logarithmic dilutions within a short span of time demonstrates the potential of this method as an alternative to conventional methods. Electronic supplementary information (ESI) available. See DOI: 10.1039/c2nr11837h

Impact of speciation on the electron charge transfer properties of nanodiamond drug carriers

NASA Astrophysics Data System (ADS)

Sun, Baichuan; Barnard, Amanda S.

2016-07-01

Unpassivated diamond nanoparticles (bucky-diamonds) exhibit a unique surface reconstruction involving graphitization of certain crystal facets, giving rise to hybrid core-shell particles containing both aromatic and aliphatic carbon. Considerable effort is directed toward eliminating the aromatic shell, but persistent graphitization of subsequent subsurface-layers makes perdurable purification a challenge. In this study we use some simple statistical methods, in combination with electronic structure simulations, to predict the impact of different fractions of aromatic and aliphatic carbon on the charge transfer properties of the ensembles of bucky-diamonds. By predicting quality factors for a variety of cases, we find that perfect purification is not necessary to preserve selectivity, and there is a clear motivation for purifying samples to improve the sensitivity of charge transfer reactions. This may prove useful in designing drug delivery systems where the release of (selected) drugs needs to be sensitive to specific conditions at the point of delivery.Unpassivated diamond nanoparticles (bucky-diamonds) exhibit a unique surface reconstruction involving graphitization of certain crystal facets, giving rise to hybrid core-shell particles containing both aromatic and aliphatic carbon. Considerable effort is directed toward eliminating the aromatic shell, but persistent graphitization of subsequent subsurface-layers makes perdurable purification a challenge. In this study we use some simple statistical methods, in combination with electronic structure simulations, to predict the impact of different fractions of aromatic and aliphatic carbon on the charge transfer properties of the ensembles of bucky-diamonds. By predicting quality factors for a variety of cases, we find that perfect purification is not necessary to preserve selectivity, and there is a clear motivation for purifying samples to improve the sensitivity of charge transfer reactions. This may prove useful in designing drug delivery systems where the release of (selected) drugs needs to be sensitive to specific conditions at the point of delivery. Electronic supplementary information (ESI) available. See DOI: 10.1039/c6nr03068h

Preliminary Validation of Direct Detection of Foot-And-Mouth Disease Virus within Clinical Samples Using Reverse Transcription Loop-Mediated Isothermal Amplification Coupled with a Simple Lateral Flow Device for Detection

PubMed Central

Waters, Ryan A.; Fowler, Veronica L.; Armson, Bryony; Nelson, Noel; Gloster, John; Paton, David J.; King, Donald P.

2014-01-01

Rapid, field-based diagnostic assays are desirable tools for the control of foot-and-mouth disease (FMD). Current approaches involve either; 1) Detection of FMD virus (FMDV) with immuochromatographic antigen lateral flow devices (LFD), which have relatively low analytical sensitivity, or 2) portable RT-qPCR that has high analytical sensitivity but is expensive. Loop-mediated isothermal amplification (LAMP) may provide a platform upon which to develop field based assays without these drawbacks. The objective of this study was to modify an FMDV-specific reverse transcription–LAMP (RT-LAMP) assay to enable detection of dual-labelled LAMP products with an LFD, and to evaluate simple sample processing protocols without nucleic acid extraction. The limit of detection of this assay was demonstrated to be equivalent to that of a laboratory based real-time RT-qPCR assay and to have a 10,000 fold higher analytical sensitivity than the FMDV-specific antigen LFD currently used in the field. Importantly, this study demonstrated that FMDV RNA could be detected from epithelial suspensions without the need for prior RNA extraction, utilising a rudimentary heat source for amplification. Once optimised, this RT-LAMP-LFD protocol was able to detect multiple serotypes from field epithelial samples, in addition to detecting FMDV in the air surrounding infected cattle, pigs and sheep, including pre-clinical detection. This study describes the development and evaluation of an assay format, which may be used as a future basis for rapid and low cost detection of FMDV. In addition it provides providing “proof of concept” for the future use of LAMP assays to tackle other challenging diagnostic scenarios encompassing veterinary and human health. PMID:25165973

Development of a sensitive and specific indirect enzyme-linked immunosorbent assay based on a baculovirus recombinant antigen for detection of specific antibodies against Ehrlichia canis.

PubMed

López, Lissett; Venteo, Angel; Aguirre, Enara; García, Marga; Rodríguez, Majosé; Amusátegui, Inmaculada; Tesouro, Miguel A; Vela, Carmen; Sainz, Angel; Rueda, Paloma

2007-11-01

An indirect enzyme-linked immunosorbent assay (ELISA) based on baculovirus recombinant P30 protein of Ehrlichia canis and the 1BH4 anticanine IgG monoclonal antibody was developed and evaluated by examining a panel of 98 positive and 157 negative sera using the indirect fluorescent antibody (IFA) test as the reference technique. The P30-based ELISA appeared to be sensitive and specific (77.55% and 95.54%, respectively) when qualitative results (positive/negative) were compared with those of the IFA test; the coefficient of correlation (R) between the 2 tests was 0.833. Furthermore, it was possible to establish a mathematical formula for use in comparing the results of both techniques. These results indicate that recombinant P30 antigen-based ELISA is a suitable alternative of the IFA test for simple, consistent, and rapid serodiagnosis of canine ehrlichiosis. Moreover, the use of this recombinant protein as antigen offers a great advantage for antigen preparation in comparison with other techniques in which the whole E. canis organism is used as antigen.

Development and evaluation of a PCR-based assay kit for authentication of Zaocys dhumnades in traditional Chinese medicine.

PubMed

Zhang, Xiaomei; Zhou, Tingting; Yu, Wenjing; Ai, Jinxia; Wang, Xuesong; Gao, Lijun; Yuan, Guangxin; Li, Mingcheng

2018-01-01

We developed a kind of Zaocys dhumnades DNA test kit and it's indexes including specificity, sensitivity and stability were evaluated and compared with the method recorded in Chinese Pharmacopoeia (2010 edition). The bioinformatics technology was used to design primers, sequencing and blast, in conjunction with PCR technology based on the characteristics of Z. dhumnades cytochrome b (Cyt b) gene. The efficiency of nucleic acid extraction by the kit was done in accordance with Pharmacopoeia method. The kit stability results proved effective after repeated freezing and thawing 20 times. The sensitivity results indicated that the lowest amount detected by the kit was 0. 025 g of each specimen. The specificity test of the kit was 100% specific. All repeatability tests indicated the same results when conducted three times. Compared with the method recorded in Chinese Pharmacopoeia, the PCR-based assay kit by our team developed is accurate, effective in identification of Z. dhumnades, it is simple and fast, demonstrating a broad prospect in quality inspection of Z. dhumnades in the future.

Semiquantitative Dot Blot with the GRA8 antigen to differentiate the stages of toxoplasmosis infection.

PubMed

Costa, Juan Gabriel; Vilariño, María Julia

2018-06-01

In this work we present a novel methodology to differentiate the phases of toxoplasmosis infection: the "semiquantitative Dot Blot". It is a simple technique that does not require expensive equipment, does not involve a long technique development, and can be used in a low-complexity laboratory. In this study, two recombinant sequences of Toxoplasma gondii GRA8 antigen were used, and specific IgG antibodies were detected in selected patient samples. This method makes it possible to obtain a score for each serum and define whether the patient is in the acute or chronic phase of the infection. The sensitivity and specificity results varied depending on the antigenic sequence used. With GRA8A, 62.1% and 72.7% were obtained, while with GRA8B, 82.8% and 72.1% were obtained, respectively. Although the sensitivity and specificity values were not close to 100%, they were similar to those reported with the same antigens in ELISA. Therefore, this quantitative technique would be a good alternative to ELISA. Copyright © 2018 Elsevier B.V. All rights reserved.

Bowel obstruction complicated by ischemia: analysis of CT findings.

PubMed

Cox, Veronica L; Tahvildari, Ali M; Johnson, Benjamin; Wei, Wei; Jeffrey, R Brooke

2018-06-01

To analyze CT signs of bowel ischemia in patients with surgical bowel obstruction, and thereby improve CT diagnosis in this common clinical scenario. Surgical and histopathological findings were used as the reference standard. We retrospectively analyzed CT findings in patients brought to surgery for bowel obstruction over 13 years. Etiology of obstruction (adhesion, hernia, etc.) was recorded. Specific CT features of acute mesenteric ischemia (AMI) were analyzed, including bowel wall thickening, mucosal hypoenhancement, and others. 173 cases were eligible for analysis. 21% of cases were positive for bowel ischemia. Volvulus, internal hernia, and closed-loop obstructions showed ischemia rates of 60%, 43%, and 43%; ischemia rate in obstruction from simple adhesion was 21%. Patients with bowel obstruction related to malignancy were never ischemic. Sensitivities and specificities for CT features predicting ischemia were calculated, with wall thickening, hypoenhancement, and pneumatosis showing high specificity for ischemia (86%-100%). Wall thickening, hypoenhancement, and pneumatosis are highly specific CT signs of ischemia in the setting of obstruction. None of the evaluated CT signs were found to be highly sensitive. Overall frequency of ischemia in surgical bowel obstruction is 21%, and 2-3 times that for complex obstructions (volvulus, closed loop, etc.). Obstructions related to malignancy virtually never become ischemic.

Malaria rapid diagnostic tests in elimination settings—can they find the last parasite?

PubMed Central

McMorrow, M. L.; Aidoo, M.; Kachur, S. P.

2016-01-01

Rapid diagnostic tests (RDTs) for malaria have improved the availability of parasite-based diagnosis throughout the malaria-endemic world. Accurate malaria diagnosis is essential for malaria case management, surveillance, and elimination. RDTs are inexpensive, simple to perform, and provide results in 15–20 min. Despite high sensitivity and specificity for Plasmodium falciparum infections, RDTs have several limitations that may reduce their utility in low-transmission settings: they do not reliably detect low-density parasitaemia (≤200 parasites/μL), many are less sensitive for Plasmodium vivax infections, and their ability to detect Plasmodium ovale and Plasmodium malariae is unknown. Therefore, in elimination settings, alternative tools with higher sensitivity for low-density infections (e.g. nucleic acid-based tests) are required to complement field diagnostics, and new highly sensitive and specific field-appropriate tests must be developed to ensure accurate diagnosis of symptomatic and asymptomatic carriers. As malaria transmission declines, the proportion of low-density infections among symptomatic and asymptomatic persons is likely to increase, which may limit the utility of RDTs. Monitoring malaria in elimination settings will probably depend on the use of more than one diagnostic tool in clinical-care and surveillance activities, and the combination of tools utilized will need to be informed by regular monitoring of test performance through effective quality assurance. PMID:21910780

Influence of Neuroblastoma Stage on Serum-Based Detection of MYCN Amplification

PubMed Central

Combaret, Valerie; Hogarty, Michael D; London, Wendy B; McGrady, Patrick; Iacono, Isabelle; Brejon, Stephanie; Swerts, Katrien; Noguera, Rosa; Gross, Nicole; Rousseau, Raphael; Puisieux, Alain

2010-01-01

Background MYCN oncogene amplification has been defined as the most important prognostic factor for neuroblastoma, the most common solid extracranial neoplasm in children. High copy numbers are strongly associated with rapid tumor progression and poor outcome, independently of tumor stage or patient age, and this has become an important factor in treatment stratification. Procedure By Real Time Quantitative PCR analysis, we evaluated the clinical relevance of circulating MYCN DNA of 267 patients with locoregional or metastatic neuroblastoma in children less than 18 months of age. Results For patients in this age group with INSS stage 4 or 4S NB and stage 3 patients, serum-based determination of MYCN DNA sequences had good sensitivity (85%, 83% and 75% respectively) and high specificity (100%) when compared to direct tumor gene determination. In contrast, the approach showed low sensitivity patients with stage 1 and 2 disease. Conclusion Our results show that the sensitivity of the serum-based MYCN DNA sequence determination depends on the stage of the disease. However, this simple, reproducible assay may represent a reasonably sensitive and very specific tool to assess tumor MYCN status in cases with stage 3 and metastatic disease for whom a wait and see strategy is often recommended. PMID:19301388

A Portable Smart-Phone Readout Device for the Detection of Mercury Contamination Based on an Aptamer-Assay Nanosensor.

PubMed

Xiao, Wei; Xiao, Meng; Fu, Qiangqiang; Yu, Shiting; Shen, Haicong; Bian, Hongfen; Tang, Yong

2016-11-08

The detection of environmental mercury (Hg) contamination requires complex and expensive instruments and professional technicians. We present a simple, sensitive, and portable Hg 2+ detection system based on a smartphone and colorimetric aptamer nanosensor. A smartphone equipped with a light meter app was used to detect, record, and process signals from a smartphone-based microwell reader (MR S-phone), which is composed of a simple light source and a miniaturized assay platform. The colorimetric readout of the aptamer nanosensor is based on a specific interaction between the selected aptamer and Hg 2+ , which leads to a color change in the reaction solution due to an aggregation of gold nanoparticles (AuNPs). The MR S-phone-based AuNPs-aptamer colorimetric sensor system could reliably detect Hg 2+ in both tap water and Pearl River water samples and produced a linear colorimetric readout of Hg 2+ concentration in the range of 1 ng/mL-32 ng/mL with a correlation of 0.991, and a limit of detection (LOD) of 0.28 ng/mL for Hg 2+ . The detection could be quickly completed in only 20 min. Our novel mercury detection assay is simple, rapid, and sensitive, and it provides new strategies for the on-site detection of mercury contamination in any environment.

A Portable Smart-Phone Readout Device for the Detection of Mercury Contamination Based on an Aptamer-Assay Nanosensor

PubMed Central

Xiao, Wei; Xiao, Meng; Fu, Qiangqiang; Yu, Shiting; Shen, Haicong; Bian, Hongfen; Tang, Yong

2016-01-01

The detection of environmental mercury (Hg) contamination requires complex and expensive instruments and professional technicians. We present a simple, sensitive, and portable Hg2+ detection system based on a smartphone and colorimetric aptamer nanosensor. A smartphone equipped with a light meter app was used to detect, record, and process signals from a smartphone-based microwell reader (MR S-phone), which is composed of a simple light source and a miniaturized assay platform. The colorimetric readout of the aptamer nanosensor is based on a specific interaction between the selected aptamer and Hg2+, which leads to a color change in the reaction solution due to an aggregation of gold nanoparticles (AuNPs). The MR S-phone-based AuNPs-aptamer colorimetric sensor system could reliably detect Hg2+ in both tap water and Pearl River water samples and produced a linear colorimetric readout of Hg2+ concentration in the range of 1 ng/mL–32 ng/mL with a correlation of 0.991, and a limit of detection (LOD) of 0.28 ng/mL for Hg2+. The detection could be quickly completed in only 20 min. Our novel mercury detection assay is simple, rapid, and sensitive, and it provides new strategies for the on-site detection of mercury contamination in any environment. PMID:27834794

DNA Electrochemistry and Electrochemical Sensors for Nucleic Acids.

PubMed

Ferapontova, Elena E

2018-06-12

Sensitive, specific, and fast analysis of nucleic acids (NAs) is strongly needed in medicine, environmental science, biodefence, and agriculture for the study of bacterial contamination of food and beverages and genetically modified organisms. Electrochemistry offers accurate, simple, inexpensive, and robust tools for the development of such analytical platforms that can successfully compete with other approaches for NA detection. Here, electrode reactions of DNA, basic principles of electrochemical NA analysis, and their relevance for practical applications are reviewed and critically discussed.

LABEL-FREE DETECTION OF Pb2+ USING SPECIFIC DNAZYME AND UNMODIFIED Au NANOPARTICLE PROBE

NASA Astrophysics Data System (ADS)

Li, Chengyong; Zhao, Zike; Liu, Yaoqian; Lv, Lulu; Qi, Bing; Lin, Haixia; He, Lei; Sun, Shengli

A simple and sensitive Pb2+ sensor is developed based on label-free 17E DNAzyme and unmodified Au nanoparticles. On this basis, Pb2+ concentration can be judged according to the color variation of Au nanoparticles. The detection limit is 100nM and linear range is 100nM-16μM. It can serve as a measurement tool for Pb2+ rapid detection, which provides reference for the development of sensors in environmental monitoring and food safety.

Spot test for 1,3,5-triamino-2,4,6-trinitrobenzene, TATB

DOEpatents

Harris, Betty W.

1986-01-01

A simple, sensitive and specific spot test for 1,3,5-triamino-2,4,6-trinitrobenzene, TATB, is described. Upon the application of the composition of matter of the present invention to samples containing in excess of 0.1 mg of this explosive, a bright orange color results. Interfering species such as TNT and Tetryl can be removed by first treating the sample with a solvent which does not dissolve much of the TATB, but readily dissolves these explosives.

Spot test for 1,3,5-triamino-2,4,6-trinitrobenzene, TATB

DOEpatents

Harris, B.W.

1984-11-29

A simple, sensitive and specific spot test for 1,3,5-triamino-2,4,6-trinitrobenzene, TATB, is described. Upon the application of the composition of matter of the subject invention to samples containing in excess of 0.1 mg of this explosive, a bright orange color results. Interfering species such as TNT and Tetryl can be removed by first treating the sample with a solvent which does not dissolve the TATB, but readily dissolves these interfering explosives.

Simulation-based sensitivity analysis for non-ignorably missing data.

PubMed

Yin, Peng; Shi, Jian Q

2017-01-01

Sensitivity analysis is popular in dealing with missing data problems particularly for non-ignorable missingness, where full-likelihood method cannot be adopted. It analyses how sensitively the conclusions (output) may depend on assumptions or parameters (input) about missing data, i.e. missing data mechanism. We call models with the problem of uncertainty sensitivity models. To make conventional sensitivity analysis more useful in practice we need to define some simple and interpretable statistical quantities to assess the sensitivity models and make evidence based analysis. We propose a novel approach in this paper on attempting to investigate the possibility of each missing data mechanism model assumption, by comparing the simulated datasets from various MNAR models with the observed data non-parametrically, using the K-nearest-neighbour distances. Some asymptotic theory has also been provided. A key step of this method is to plug in a plausibility evaluation system towards each sensitivity parameter, to select plausible values and reject unlikely values, instead of considering all proposed values of sensitivity parameters as in the conventional sensitivity analysis method. The method is generic and has been applied successfully to several specific models in this paper including meta-analysis model with publication bias, analysis of incomplete longitudinal data and mean estimation with non-ignorable missing data.

Establishment of the cross-clade antigen detection system for H5 subtype influenza viruses using peptide monoclonal antibodies specific for influenza virus H5 hemagglutinin.

PubMed

Takahashi, Hitoshi; Nagata, Shiho; Odagiri, Takato; Kageyama, Tsutomu

2018-04-15

The H5 subtype of highly pathogenic avian influenza (H5 HPAI) viruses is a threat to both animal and human public health and has the potential to cause a serious future pandemic in humans. Thus, specific and rapid detection of H5 HPAI viruses is required for infection control in humans. To develop a simple and rapid diagnostic system to detect H5 HPAI viruses with high specificity and sensitivity, we attempted to prepare monoclonal antibodies (mAbs) that specifically recognize linear epitopes in hemagglutinin (HA) of H5 subtype viruses. Nine mAb clones were obtained from mice immunized with a synthetic partial peptide of H5 HA molecules conserved among various H5 HPAI viruses. The antigen-capture enzyme-linked immunosorbent assay using the most suitable combination of these mAbs, which bound specifically to lysed H5 HA under an optimized detergent condition, was specific for H5 viruses and could broadly detect H5 viruses in multiple different clades. Taken together, these peptide mAbs, which recognize linear epitopes in a highly conserved region of H5 HA, may be useful for specific and highly sensitive detection of H5 HPAI viruses and can help in the rapid diagnosis of human, avian, and animal H5 virus infections. Copyright © 2018 Elsevier Inc. All rights reserved.

Detection of Sub-fM DNA with Target Recycling and Self-Assembly Amplification on Graphene Field-Effect Biosensors

PubMed Central

2018-01-01

All-electronic DNA biosensors based on graphene field-effect transistors (GFETs) offer the prospect of simple and cost-effective diagnostics. For GFET sensors based on complementary probe DNA, the sensitivity is limited by the binding affinity of the target oligonucleotide, in the nM range for 20 mer targets. We report a ∼20 000× improvement in sensitivity through the use of engineered hairpin probe DNA that allows for target recycling and hybridization chain reaction. This enables detection of 21 mer target DNA at sub-fM concentration and provides superior specificity against single-base mismatched oligomers. The work is based on a scalable fabrication process for biosensor arrays that is suitable for multiplexed detection. This approach overcomes the binding-affinity-dependent sensitivity of nucleic acid biosensors and offers a pathway toward multiplexed and label-free nucleic acid testing with high accuracy and selectivity. PMID:29768011

Detection of Sub-fM DNA with Target Recycling and Self-Assembly Amplification on Graphene Field-Effect Biosensors.

PubMed

Gao, Zhaoli; Xia, Han; Zauberman, Jonathan; Tomaiuolo, Maurizio; Ping, Jinglei; Zhang, Qicheng; Ducos, Pedro; Ye, Huacheng; Wang, Sheng; Yang, Xinping; Lubna, Fahmida; Luo, Zhengtang; Ren, Li; Johnson, Alan T Charlie

2018-06-13

All-electronic DNA biosensors based on graphene field-effect transistors (GFETs) offer the prospect of simple and cost-effective diagnostics. For GFET sensors based on complementary probe DNA, the sensitivity is limited by the binding affinity of the target oligonucleotide, in the nM range for 20 mer targets. We report a ∼20 000× improvement in sensitivity through the use of engineered hairpin probe DNA that allows for target recycling and hybridization chain reaction. This enables detection of 21 mer target DNA at sub-fM concentration and provides superior specificity against single-base mismatched oligomers. The work is based on a scalable fabrication process for biosensor arrays that is suitable for multiplexed detection. This approach overcomes the binding-affinity-dependent sensitivity of nucleic acid biosensors and offers a pathway toward multiplexed and label-free nucleic acid testing with high accuracy and selectivity.

Sensitive PCR Detection of Meloidogyne arenaria, M. incognita, and M. javanica Extracted from Soil

PubMed Central

Qiu, Jinya Jack; Westerdahl, Becky B.; Anderson, Cindy; Williamson, Valerie M.

2006-01-01

We have developed a simple PCR assay protocol for detection of the root-knot nematode (RKN) species Meloidogyne arenaria, M. incognita, and M. javanica extracted from soil. Nematodes are extracted from soil using Baermann funnels and centrifugal flotation. The nematode-containing fraction is then digested with proteinase K, and a PCR assay is carried out with primers specific for this group of RKN and with universal primers spanning the ITS of rRNA genes. The presence of RKN J2 can be detected among large numbers of other plant-parasitic and free-living nematodes. The procedure was tested with several soil types and crops from different locations and was found to be sensitive and accurate. Analysis of unknowns and spiked soil samples indicated that detection sensitivity was the same as or higher than by microscopic examination. PMID:19259460

A rapid and sensitive dot-blot hybridization assay for the detection of citrus exocortis viroid in Citrus medica with digoxigenin-labelled RNA probes.

PubMed

Fonseca, M E; Marcellino, L H; Gander, E

1996-04-05

A rapid and sensitive dot-blot hybridization assay using in vitro-transcribed digoxigenin-labelled RNA probes (riboprobes) was developed aiming at detection of citrus exocortis viroid (CEVd) in crude sap of infected Citrus medica plants. The protocol includes a very quick and simple preparation of RNA extracts from samples using a denaturation step with formaldehyde. From our results, the employment of this step is highly recommended because the hybridization signals in formaldehyde-denatured samples were significantly stronger when compared with that of extracts without formaldehyde treatment. The assay was found to be sensitive enough to detect 0.1 ng of purified CEVd RNA and was able to detect viroid in 0.2 mg of symptomatic Citrus medica leaves. The use of riboprobes also allowed hybridization under high temperature conditions, avoiding non-specific background.

Homogeneous versus heterogeneous probes for microbial ecological microarrays.

PubMed

Bae, Jin-Woo; Park, Yong-Ha

2006-07-01

Microbial ecological microarrays have been developed for investigating the composition and functions of microorganism communities in environmental niches. These arrays include microbial identification microarrays, which use oligonucleotides, gene fragments or microbial genomes as probes. In this article, the advantages and disadvantages of each type of probe are reviewed. Oligonucleotide probes are currently useful for probing uncultivated bacteria that are not amenable to gene fragment probing, whereas the functional gene fragments amplified randomly from microbial genomes require phylogenetic and hierarchical categorization before use as microbial identification probes, despite their high resolution for both specificity and sensitivity. Until more bacteria are sequenced and gene fragment probes are thoroughly validated, heterogeneous bacterial genome probes will provide a simple, sensitive and quantitative tool for exploring the ecosystem structure.

DNA detection using water-soluble conjugated polymers and peptide nucleic acid probes

PubMed Central

Gaylord, Brent S.; Heeger, Alan J.; Bazan, Guillermo C.

2002-01-01

The light-harvesting properties of cationic conjugated polymers are used to sensitize the emission of a dye on a specific peptide nucleic acid (PNA) sequence for the purpose of homogeneous, “real-time” DNA detection. Signal transduction is controlled by hybridization of the neutral PNA probe and the negative DNA target. Electrostatic interactions bring the hybrid complex and cationic polymer within distances required for Förster energy transfer. Conjugated polymer excitation provides fluorescein emission >25 times higher than that obtained by exciting the dye, allowing detection of target DNA at concentrations of 10 pM with a standard fluorometer. A simple and highly sensitive assay with optical amplification that uses the improved hybridization behavior of PNA/DNA complexes is thus demonstrated. PMID:12167673

Simple Identification of Human Taenia Species by Multiplex Loop-Mediated Isothermal Amplification in Combination with Dot Enzyme-Linked Immunosorbent Assay

PubMed Central

Nkouawa, Agathe; Sako, Yasuhito; Okamoto, Munehiro; Ito, Akira

2016-01-01

For differential detection of Taenia solium, Taenia saginata, and Taenia asiatica, loop-mediated isothermal amplification (LAMP) assay targeting the cytochrome c oxidase subunit 1 gene has been recently developed and shown to be sensitive, specific, and effective. However, to achieve differential identification, one specimen requires three reaction mixtures containing a primer set of each Taenia species separately, which is complex and time consuming and increases the risk of cross-contamination. In this study, we developed a simple differential identification of human Taenia species using multiplex LAMP (mLAMP) in combination with dot enzyme-linked immunosorbent assay (dot-ELISA). Forward inner primers of T. solium, T. saginata, and T. asiatica labeled with fluorescein isothiocyanate (FITC), digoxigenin (DIG), and tetramethylrhodamine (TAMRA), respectively, and biotin-labeled backward inner primers were used in mLAMP. The mLAMP assay succeeded in specific amplification of each respective target gene in a single tube. Furthermore, the mLAMP product from each species was easily distinguished by dot-ELISA with an antibody specific for FITC, DIG, or TAMRA. The mLAMP assay in combination with dot-ELISA will make identification of human Taenia species simpler, easier, and more practical. PMID:27044566

Comparison of two PCR-based methods and automated DNA sequencing for prop-1 genotyping in Ames dwarf mice.

PubMed

Gerstner, Arpad; DeFord, James H; Papaconstantinou, John

2003-07-25

Ames dwarfism is caused by a homozygous single nucleotide mutation in the pituitary specific prop-1 gene, resulting in combined pituitary hormone deficiency, reduced growth and extended lifespan. Thus, these mice serve as an important model system for endocrinological, aging and longevity studies. Because the phenotype of wild type and heterozygous mice is undistinguishable, it is imperative for successful breeding to accurately genotype these animals. Here we report a novel, yet simple, approach for prop-1 genotyping using PCR-based allele-specific amplification (PCR-ASA). We also compare this method to other potential genotyping techniques, i.e. PCR-based restriction fragment length polymorphism analysis (PCR-RFLP) and fluorescence automated DNA sequencing. We demonstrate that the single-step PCR-ASA has several advantages over the classical PCR-RFLP because the procedure is simple, less expensive and rapid. To further increase the specificity and sensitivity of the PCR-ASA, we introduced a single-base mismatch at the 3' penultimate position of the mutant primer. Our results also reveal that the fluorescence automated DNA sequencing has limitations for detecting a single nucleotide polymorphism in the prop-1 gene, particularly in heterozygotes.

A Comparative Proteomic Analysis of the Simple Amino Acid Repeat Distributions in Plasmodia Reveals Lineage Specific Amino Acid Selection

PubMed Central

Dalby, Andrew R.

2009-01-01

Background Microsatellites have been used extensively in the field of comparative genomics. By studying microsatellites in coding regions we have a simple model of how genotypic changes undergo selection as they are directly expressed in the phenotype as altered proteins. The simplest of these tandem repeats in coding regions are the tri-nucleotide repeats which produce a repeat of a single amino acid when translated into proteins. Tri-nucleotide repeats are often disease associated, and are also known to be unstable to both expansion and contraction. This makes them sensitive markers for studying proteome evolution, in closely related species. Results The evolutionary history of the family of malarial causing parasites Plasmodia is complex because of the life-cycle of the organism, where it interacts with a number of different hosts and goes through a series of tissue specific stages. This study shows that the divergence between the primate and rodent malarial parasites has resulted in a lineage specific change in the simple amino acid repeat distribution that is correlated to A–T content. The paper also shows that this altered use of amino acids in SAARs is consistent with the repeat distributions being under selective pressure. Conclusions The study shows that simple amino acid repeat distributions can be used to group related species and to examine their phylogenetic relationships. This study also shows that an outgroup species with a similar A–T content can be distinguished based only on the amino acid usage in repeats, and suggest that this might be a useful feature for proteome clustering. The lineage specific use of amino acids in repeat regions suggests that comparative studies of SAAR distributions between proteomes gives an insight into the mechanisms of expansion and the selective pressures acting on the organism. PMID:19597555

Amplified QCM biosensor for type IV collagenase based on collagenase-cleavage of gold nanoparticles functionalized peptide.

PubMed

Dong, Zong-Mu; Jin, Xin; Zhao, Guang-Chao

2018-05-30

The present study develops a rapid, simple and efficient method for the determination of type IV collagenase by using a specific peptide-modified quartz crystal microbalance (QCM). A small peptide (P1), contains a specific sequence (Pro-Gly) and a terminal cysteine, was synthetized and immobilized to the surface of QCM electrode via the reaction between Au and thiol of the cysteine. The peptide bond between proline and glycine can be specific hydrolyzed cleavage by type IV collagenase, which enabled the modified electrode with a high selectivity toward type IV collagenase. The cleaving process caused a frequency change of QCM to give a signal related to the concentration of type IV collagenase. The morphologies of the modified electrodes were characterized by scanning electron microscope (SEM) and the specific hydrolyzed cleavage process was monitored by QCM. When P1 was modified with gold nanoparticles (P1-Au NPs), the signal could be amplified to further enhance the sensitivity of the designed sensor due to the high-mass of the modified Au NPs. Compared the direct unamplified assay, the values obtained for the limit of detection for type IV collagenase was 0.96 ng mL -1 , yielding about 6.5 times of magnitude improvement in sensitivity. This signal enhanced peptide based QCM biosensor for type IV collagenase also showed good selectivity and sensitivity in complex matrix. Copyright © 2018 Elsevier B.V. All rights reserved.

Use of electronic data and existing screening tools to identify clinically significant obstructive sleep apnea.

PubMed

Severson, Carl A; Pendharkar, Sachin R; Ronksley, Paul E; Tsai, Willis H

2015-01-01

To assess the ability of electronic health data and existing screening tools to identify clinically significant obstructive sleep apnea (OSA), as defined by symptomatic or severe OSA. The present retrospective cohort study of 1041 patients referred for sleep diagnostic testing was undertaken at a tertiary sleep centre in Calgary, Alberta. A diagnosis of clinically significant OSA or an alternative sleep diagnosis was assigned to each patient through blinded independent chart review by two sleep physicians. Predictive variables were identified from online questionnaire data, and diagnostic algorithms were developed. The performance of electronically derived algorithms for identifying patients with clinically significant OSA was determined. Diagnostic performance of these algorithms was compared with versions of the STOP-Bang questionnaire and adjusted neck circumference score (ANC) derived from electronic data. Electronic questionnaire data were highly sensitive (>95%) at identifying clinically significant OSA, but not specific. Sleep diagnostic testing-determined respiratory disturbance index was very specific (specificity ≥95%) for clinically relevant disease, but not sensitive (<35%). Derived algorithms had similar accuracy to the STOP-Bang or ANC, but required fewer questions and calculations. These data suggest that a two-step process using a small number of clinical variables (maximizing sensitivity) and objective diagnostic testing (maximizing specificity) is required to identify clinically significant OSA. When used in an online setting, simple algorithms can identify clinically relevant OSA with similar performance to existing decision rules such as the STOP-Bang or ANC.

Development and Evaluation of a Loop-Mediated Isothermal Amplification (Lamp) Assay for the Detection of Haemonchus contortus in Goat Fecal Samples.

PubMed

Yang, X; Qi, M W; Zhang, Z Z; Gao, C; Wang, C Q; Lei, W Q; Tan, L; Zhao, J L; Fang, R; Hu, M

2017-04-01

Haemonchus contortus is one of the most significant strongylid nematodes infecting small ruminants, and it causes great economic losses to the livestock industry worldwide. Accurate diagnosis of H. contortus is crucial to control strategies. Traditional microscopic examinations are the most common methods for the diagnosis of H. contortus , but they are time-consuming and inaccurate. Molecular methods based on PCR are more accurate, but need expensive machines usually only used in the laboratory. Loop-mediated isothermal amplification (LAMP) is a rapid, simple, specific, and sensitive method that has been widely used to detect viruses, bacteria, and parasites. In the present study, a LAMP method targeting ribosomal ITS-2 gene for detection of the H. contortus in goat fecal samples has been established. The established LAMP method was H. contortus specific, and the sensitivity of LAMP was the same as that of the H. contortus species-specific PCR, with the lowest DNA level detected as being 1 pg. Examination of the clinical samples indicated that the positive rate of LAMP was higher than that of PCR, but no statistical difference was observed between LAMP and PCR (χ 2 = 17.991, P = 0.053). In conclusion, a LAMP assay with a high specificity and a good sensitivity has been developed to detect H. contortus infection in goats. The established LAMP assay is useful for clinical diagnosis of H. contortus .

A simple, rapid, cost-effective and sensitive method for detection of Salmonella in environmental and pecan samples.

PubMed

Dobhal, S; Zhang, G; Rohla, C; Smith, M W; Ma, L M

2014-10-01

PCR is widely used in the routine detection of foodborne human pathogens; however, challenges remain in overcoming PCR inhibitors present in some sample matrices. The objective of this study was to develop a simple, sensitive, cost-effective and rapid method for processing large numbers of environmental and pecan samples for Salmonella detection. This study was also aimed at validation of a new protocol for the detection of Salmonella from in-shell pecans. Different DNA template preparation methods, including direct boiling, prespin, multiple washing and commercial DNA extraction kits, were evaluated with pure cultures of Salmonella Typhimurium and with enriched soil, cattle feces and in-shell pecan each spiked individually with Salmonella Typhimurium. PCR detection of Salmonella was conducted using invA and 16S rRNA gene (internal amplification control) specific primers. The effect of amplification facilitators, including bovine serum albumin (BSA), polyvinylpyrrolidone (PVP), polyethylene glycol (PEG) and gelatin on PCR sensitivity, was also evaluated. Conducting a prespin of sample matrices in combination with the addition of 0·4% (w/v) BSA and 1% (w/v) PVP in PCR mix was the simplest, most rapid, cost-effective and sensitive method for PCR detection of Salmonella, with up to 40 CFU Salmonella per reaction detectable in the presence of over 10(9 ) CFU ml(-1) of background micro-organisms from enriched feces soil or pecan samples. The developed method is rapid, cost-effective and sensitive for detection of Salmonella from different matrices. This study provides a method with broad applicability for PCR detection of Salmonella in complex sample matrices. This method has a potential for its application in different research arenas and diagnostic laboratories. © 2014 The Society for Applied Microbiology.

Surrogate markers of subtle renal injury in patients with visceral leishmaniasis.

PubMed

Elnojomi, N A A; Musa, A M; Younis, B M; Elfaki, M E E; El-Hassan, A M; Khalil, E A G

2010-09-01

Sudanese visceral leishmaniasis (VL) is a disease of children that is characterized by fever, hepatosplenomegaly, lymphadenopathy, pancytopenia, and renal injury. Microalbuminuria (MA) and urinary retinol binding protein (urRBP) are useful markers for glomerular and tubular dysfunctions, respectively. We report the prevalence of subtle renal injury in 88 parasitologically confirmed VL patients in a cross-sectional and hospital-based study. Blood and urine were collected before treatment for hematological, biochemical profiles in addition to MA and urRBP measurement using competitive solid phase, sandwich enzyme-linked immune sorbent assay (ELISA), and immunoturbidometry. All the patients had normal serum urea and creatinine levels and no detectable urRBP. However, 40% of the patients had MA detected by ELISA, and 42% were reactive with turbidometry. The sensitivity, specificity, positive and negative predictive values for MA turbidometric technique were calculated as 100%; 96%; 95% and 100%, respectively. In conclusion; subtle renal injury in VL is mainly glomerular. Turbidometry for MA measurement is a simple, inexpensive, sensitive, and specific technique with high predictive values.

A quick and simple FISH protocol with hybridization-sensitive fluorescent linear oligodeoxynucleotide probes

PubMed Central

Wang, Dan Ohtan; Matsuno, Hitomi; Ikeda, Shuji; Nakamura, Akiko; Yanagisawa, Hiroyuki; Hayashi, Yasunori; Okamoto, Akimitsu

2012-01-01

Fluorescence in situ hybridization (FISH) is a powerful tool used in karyotyping, cytogenotyping, cancer diagnosis, species specification, and gene-expression analysis. Although widely used, conventional FISH protocols are cumbersome and time consuming. We have now developed a FISH method using exciton-controlled hybridization-sensitive fluorescent oligodeoxynucleotide (ECHO) probes. ECHO–FISH uses a 25-min protocol from fixation to mounting that includes no stringency washing steps. We use ECHO–FISH to detect both specific DNA and RNA sequences with multicolor probes. ECHO–FISH is highly reproducible, stringent, and compatible with other fluorescent cellular labeling techniques. The resolution allows detection of intranuclear speckles of poly(A) RNA in HeLa cells and dissociated hippocampal primary cultures, and mRNAs in the distal dendrites of hippocampal neurons. We also demonstrate detection of telomeric and centromeric DNA on metaphase mouse chromosomes. The simplicity of the ECHO–FISH method will likely accelerate cytogenetic and gene-expression analysis with high resolution. PMID:22101241

Profile of the Alere i Influenza A & B assay: a pioneering molecular point-of-care test.

PubMed

Wang, Hongmei; Deng, Jikui; Tang, Yi-Wei

2018-05-01

The Alere i Influenza A & B assay incorporates the Nicking Enzyme Amplification Reaction technique on the Alere i instrument to detect and differentiate influenza virus (Flu) A and B nucleic acids in specific specimens. Areas covered: The Alere i Influenza A & B assay was cleared by the US Food and Drug Administration for use with nasal swabs (NS) and nasopharyngeal swabs, either directly or in viral transport medium. Notably, direct use on NS was the first ever CLIA-waived nucleic acid-based test. Previously published evaluations have reported sensitivities and specificities of 55.2-100% and 62.5-100% for Flu A and 45.2-100% and 53.6-100% for Flu B, respectively. Expert commentary: The Alere i Influenza A & B assay provides a rapid and simple platform for detection and differentiation of Flu A and B. Efforts are expected to further improve sensitivity and user-friendliness for effective and widespread use in the true point-of-care setting.

C-reactive Protein Versus Neutrophil/lymphocyte Ratio in Differentiating Bacterial and Non-bacterial Pneumonia in Children.

PubMed

Gauchan, E; Adhikari, S

2016-09-01

Pneumonia is a leading cause of childhood mortality in a low resource country. Simple laboratory markers can help differentiate between bacterial and non-bacterial pneumonias for appropriate management. In children aged one to 60 months with features of lower respiratory infection, C-reactive protein (CRP) and neutrophil-lymphocyte ratio (NLR) were used to differentiate between bacterial and non-bacterial pneumonias. The cutoff values for detecting bacterial pneumonias were evaluated by statistical tools. Bacterial pneumonia was diagnosed in 285 (43.6%) children out of 654 studied. At a cut-off value of 36 mg/L CRP was predictive of bacterial pneumonias with sensitivity and specificity of 61.8% and 91.3% respectively while the sensitivity and specificity for predicting bacterial pneumonia using NLR was 45.6% and 64% respectively with 1.28 used as a cut-off. Our study shows that CRP is superior to NLR in differentiating bacterial from non-bacterial pneumonias in children.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yoo, Yong Kyoung; Center for Biomicrosystems, Korea Institute of Science and Technology, Seoul 136-791; Lee, Sang-Myung

Combining a highly sensitive sensor platform with highly selective recognition elements is essential for micro/nanotechnology-based electronic nose applications. Particularly, the regeneration sensor surface and its conditions are key issues for practical e-nose applications. We propose a highly sensitive piezoelectric-driven microcantilever array chip with highly selective peptide receptors. By utilizing the peptide receptor, which was discovered by a phase display screening process, we immobilized a dinitrotoluene (DNT) specific peptide as well as a DNT nonspecific peptide on the surface of the cantilever array. The delivery of DNT gas via pressure-driven flow led to a greater instant response of ∼30 Hz, compared tomore » diffusion only (∼15 Hz for 15 h). Using a simple pressure-driven air flow of ∼50 sccm, we confirmed that a ratio of ∼70% of the specific-bounded sites from DNT gas molecules could be regenerated, showing re-usability of the peptide receptor in on-site monitoring for electronic nose applications.« less

Protein microarray with horseradish peroxidase chemiluminescence for quantification of serum α-fetoprotein.

PubMed

Zhao, Yuanshun; Zhang, Yonghong; Lin, Dongdong; Li, Kang; Yin, Chengzeng; Liu, Xiuhong; Jin, Boxun; Sun, Libo; Liu, Jinhua; Zhang, Aiying; Li, Ning

2015-10-01

To develop and evaluate a protein microarray assay with horseradish peroxidase (HRP) chemiluminescence for quantification of α-fetoprotein (AFP) in serum from patients with hepatocellular carcinoma (HCC). A protein microarray assay for AFP was developed. Serum was collected from patients with HCC and healthy control subjects. AFP was quantified using protein microarray and enzyme-linked immunosorbent assay (ELISA). Serum AFP concentrations determined via protein microarray were positively correlated (r = 0.973) with those determined via ELISA in patients with HCC (n = 60) and healthy control subjects (n = 30). Protein microarray showed 80% sensitivity and 100% specificity for HCC diagnosis. ELISA had 83.3% sensitivity and 100% specificity. Protein microarray effectively distinguished between patients with HCC and healthy control subjects (area under ROC curve 0.974; 95% CI 0.000, 1.000). Protein microarray is a rapid, simple and low-cost alternative to ELISA for detecting AFP in human serum. © The Author(s) 2015.

Intervals for posttest probabilities: a comparison of 5 methods.

PubMed

Mossman, D; Berger, J O

2001-01-01

Several medical articles discuss methods of constructing confidence intervals for single proportions and the likelihood ratio, but scant attention has been given to the systematic study of intervals for the posterior odds, or the positive predictive value, of a test. The authors describe 5 methods of constructing confidence intervals for posttest probabilities when estimates of sensitivity, specificity, and the pretest probability of a disorder are derived from empirical data. They then evaluate each method to determine how well the intervals' coverage properties correspond to their nominal value. When the estimates of pretest probabilities, sensitivity, and specificity are derived from more than 80 subjects and are not close to 0 or 1, all methods generate intervals with appropriate coverage properties. When these conditions are not met, however, the best-performing method is an objective Bayesian approach implemented by a simple simulation using a spreadsheet. Physicians and investigators can generate accurate confidence intervals for posttest probabilities in small-sample situations using the objective Bayesian approach.

A simple and sensitive method for determining plasma cell isotype and monoclonality in bone marrow using flowcytometry.

PubMed

van Zaanen, H C; Vet, R J; de Jong, C M; von dem Borne, A E; van Oers, M H

1995-09-01

In this paper we describe a new, rapid and sensitive method to determine plasma cell isotype and clonality in bone marrow using flowcytometry. With the use of a new fixation and permeabilization reagent (Permeafix), which preserves cell structure and morphology, and a monoclonal antibody (Mab) specific for plasma cells (B-B4), it has become possible to specifically select plasma cells and to determine the cytoplasmatic immunoglobulins by flowcytometry. Thirty successive bone marrow aspirates from multiple myeloma patients and patients with MGUS were studied as well as 10 bone marrow samples from patients with reactive plasmacytosis. Each sample was analysed both by immunofluorescence on cytospin smears and FACS analysis. There were no discrepancies between plasma cell isotype as determined by FACS and cytospin. Moreover, FACS analysis was shown to allow detection of very low numbers of plasma cells and to determine whether these plasma cells are mono- or polyclonal. Possible applications are discussed.

Highly sensitive determination of diclofenac based on resin beads and a novel polyclonal antibody by using flow injection chemiluminescence competitive immunoassay

NASA Astrophysics Data System (ADS)

Shi, Jing; Xu, Mingxia; Tang, Qinghui; Zhao, Kang; Deng, Anping; Li, Jianguo

2018-02-01

A novel flow injection chemiluminescence immunoassay for simple, sensitive and low-cost detection of diclofenac was established based on specific binding of antigen and antibody. Carboxylic resin beads used as solid phase carrier materials provided good biocompatibility and large surface-to-volume ratio for modifying more coating antigen. There was a competitive process between the diclofenac in solution and the immobilized coating antigen to react with the limited binding sites of the polyclonal antibody to form the immunocomplex. The second antibody labelled with horseradish peroxidase was introduced into the immunosensor and trapped by captured polyclonal antibody against diclofenac, which could effectively amplify chemiluminescence signals of luminol-PIP-H2O2. Under optimal conditions, the diclofenac could be detected quantitatively. The chemiluminescence intensity decreased linearly with the logarithm of the diclofenac concentration in the range of 0.1-100 ng mL- 1 with a detection limit of 0.05 ng mL- 1 at a signal-to-noise ratio of 3. The immunosensor exhibited high sensitivity, specificity and acceptable stability. This easy-operated and cost-effective analytical method could be valuable for the diclofenac determination in real water samples.

Label-Enhanced Surface Plasmon Resonance: A New Concept for Improved Performance in Optical Biosensor Analysis

PubMed Central

Granqvist, Niko; Hanning, Anders; Eng, Lars; Tuppurainen, Jussi; Viitala, Tapani

2013-01-01

Surface plasmon resonance (SPR) is a well-established optical biosensor technology with many proven applications in the study of molecular interactions as well as in surface and material science. SPR is usually applied in the label-free mode which may be advantageous in cases where the presence of a label may potentially interfere with the studied interactions per se. However, the fundamental challenges of label-free SPR in terms of limited sensitivity and specificity are well known. Here we present a new concept called label-enhanced SPR, which is based on utilizing strongly absorbing dye molecules in combination with the evaluation of the full shape of the SPR curve, whereby the sensitivity as well as the specificity of SPR is significantly improved. The performance of the new label-enhanced SPR method was demonstrated by two simple model assays: a small molecule assay and a DNA hybridization assay. The small molecule assay was used to demonstrate the sensitivity enhancement of the method, and how competitive assays can be used for relative affinity determination. The DNA assay was used to demonstrate the selectivity of the assay, and the capabilities in eliminating noise from bulk liquid composition variations. PMID:24217357

DNA-Encoded Raman-Active Anisotropic Nanoparticles for microRNA Detection.

PubMed

Qi, Lin; Xiao, Mingshu; Wang, Xiwei; Wang, Cheng; Wang, Lihua; Song, Shiping; Qu, Xiangmeng; Li, Li; Shi, Jiye; Pei, Hao

2017-09-19

The development of highly sensitive and selective methods for the detection of microRNA (miRNA) has attracted tremendous attention because of its importance in fundamental biological studies and diagnostic applications. In this work, we develop DNA-encoded Raman-active anisotropic nanoparticles modified origami paper analytical devices (oPADs) for rapid, highly sensitive, and specific miRNA detection. The Raman-active anisotropic nanoparticles were prepared using 10-mer oligo-A, -T, -C, and -G to mediate the growth of Ag cubic seeds into Ag nanoparticles (AgNPs) with different morphologies. The resulting AgNPs were further encoded with DNA probes to serve as effective surface-enhanced Raman scattering (SERS) probes. The analytical device was then fabricated on a single piece of SERS probes loaded paper-based substrate and assembled based on the principles of origami. The addition of the target analyte amplifies the Raman signals on DNA-encoded AgNPs through a target-dependent, sequence specific DNA hybridization assembly. This simple and low-cost analytical device is generic and applicable to a variety of miRNAs, allowing detection sensitivity down to 1 pM and assay time within 15 min, and therefore holds promising applications in point-of-care diagnostics.

GaAs Coupled Micro Resonators with Enhanced Sensitive Mass Detection

PubMed Central

Chopard, Tony; Lacour, Vivien; Leblois, Therese

2014-01-01

This work demonstrates the improvement of mass detection sensitivity and time response using a simple sensor structure. Indeed, complicated technological processes leading to very brittle sensing structures are often required to reach high sensitivity when we want to detect specific molecules in biological fields. These developments constitute an obstacle to the early diagnosis of diseases. An alternative is the design of coupled structures. In this study, the device is based on the piezoelectric excitation and detection of two GaAs microstructures vibrating in antisymmetric modes. GaAs is a crystal which has the advantage to be micromachined easily using typical clean room processes. Moreover, we showed its high potential in direct biofunctionalisation for use in the biological field. A specific design of the device was performed to improve the detection at low mass and an original detection method has been developed. The principle is to exploit the variation in amplitude at the initial resonance frequency which has in the vicinity of weak added mass the greatest slope. Therefore, we get a very good resolution for an infinitely weak mass: relative voltage variation of 8%/1 fg. The analysis is based on results obtained by finite element simulation. PMID:25474375

Diagnosis of uterine cervix cancer using Müller polarimetry: a comparison with histopathology

NASA Astrophysics Data System (ADS)

Rehbinder, Jean; Deby, Stanislas; Haddad, Huda; Teig, Benjamin; Nazac, André; Pierangelo, Angelo; Moreau, François

2015-07-01

Today around 275000 women a year in the world keep dying from the cancer of uterine cervix due to the difficulty to meet the logistic requirements of an organized screening in the developing world. Polarimetric imaging is a new promising technique with a tremendous potential for applications in biomedical diagnostics: it is sensitive to slight morphological changes in tissues, can provide wide field images for the screening and requires light sources such as a LED for example. This work intends to characterize the polarimetric response of the uterine cervix in its healthy and pathological states. An extensive series of ex-vivo measurements is in progress the Kremlin Bicêtre hospital near Paris using an imaging multispectral Mueller polarimeter in backscattering configuration. The goal of this study is to evaluate the performances of polarimetric imaging technique in terms of sensitivity and specificity for the detection of healthy epithelia (Healthy Squamous epithelium and Malpighian Metaplasia) with respect to the diagnosis provided by pathologists from histology slides as the "gold standard". We show that, at λ=550nm, performances as high as 62% sensitivity and 64% specificity are achieved by optimizing a simple threshold on the scalar retardance values.

Application of a loop-mediated isothermal amplification (LAMP) assay targeting cox1 gene for the detection of Clonorchis sinensis in human fecal samples

PubMed Central

Rahman, S. M. Mazidur; Song, Hyun Beom; Jin, Yan; Oh, Jin-Kyoung; Lim, Min Kyung; Hong, Sung-Tae

2017-01-01

Background Clonorchiasis is prevalent in the Far East, and a major health problem in endemic areas. Infected persons may experience, if not treated, serious complications such as bile stone formation, pyogenic cholangitis, and even cholangiocarcinoma. Early diagnosis and treatment are important to prevent serious complications and, therefore, the simple and reliable diagnostic method is necessary to control clonorchiasis in endemic areas, where resources for the diagnosis are limited. Methodology/Principle findings The loop-mediated isothermal amplification (LAMP) assay has been applied for the detection of Clonorchis sinensis DNA. Six primers targeting eight locations on the cytochrome c oxidase subunit 1 gene of C. sinensis were designed for species-specific amplification using the LAMP assay. The LAMP assay was sensitive enough to detect as little as 100 fg of C. sinensis genomic DNA and the detection limit in 100 mg of stool was as low as one egg. The assay was highly specific because no cross-reactivity was observed with the DNA of other helminths, protozoa or Escherichia coli. Then, LAMP assay was applied to human fecal samples collected from an endemic area of clonorchiasis in Korea. Using samples showing consistent results by both Kato-Katz method and real-time PCR as reference standards, the LAMP assay showed 97.1% (95% CI, 90.1–99.2) of sensitivity and 100% (95% CI, 92.9–100) of specificity. In stool samples with more than 100 eggs per gram of feces, the sensitivity achieved 100%. Conclusions To detect C. sinensis in human fecal samples, the LAMP assay was applied and achieved high sensitivity and specificity. The LAMP assay can be utilized in field laboratories as a powerful tool for diagnosis and epidemiological survey of clonorchiasis. PMID:28991924

Relationship between Grooming Performance and Motor and Cognitive Functions in Stroke Patients with Receiver Operating Characteristic Analysis.

PubMed

Fujita, Takaaki; Sato, Atsushi; Tsuchiya, Kenji; Ohashi, Takuro; Yamane, Kazuhiro; Yamamoto, Yuichi; Iokawa, Kazuaki; Ohira, Yoko; Otsuki, Koji; Tozato, Fusae

2017-12-01

This study aimed to elucidate the relationship between grooming performance of stroke patients and various motor and cognitive functions and to examine the cognitive and physical functional standards required for grooming independence. We retrospectively analyzed the data of 96 hospitalized patients with first stroke in a rehabilitation hospital ward. Logistic regression analysis and receiver operating characteristic curves were used to investigate the related cognitive and motor functions with grooming performance and to calculate the cutoff values for independence and supervision levels in grooming. For analysis between the independent and supervision-dependent groups, the only item with an area under the curve (AUC) of .9 or higher was the Berg Balance Scale, and the calculated cutoff value was 41/40 (sensitivity, 83.6%; specificity, 87.8%). For analysis between the independent-supervision and dependent groups, the items with an AUC of .9 or higher were the Simple Test for Evaluating Hand Function (STEF) on the nonaffected side, Vitality Index (VI), and FIM ® cognition. The cutoff values were 68/67 for the STEF (sensitivity, 100%; specificity, 72.2%), 9/8 points for the VI (sensitivity, 92.3%; specificity, 88.9%), and 23/22 points for FIM ® cognition (sensitivity, 91.0%; specificity, 88.9%). Our results suggest that upper-extremity functions on the nonaffected side, motivation, and cognitive functions are particularly important to achieve the supervision level and that balance is important to reach the independence level. The effective improvement of grooming performance is possible by performing therapeutic or compensatory intervention on functions that have not achieved these cutoff values. Copyright © 2017 National Stroke Association. Published by Elsevier Inc. All rights reserved.

Application of a loop-mediated isothermal amplification (LAMP) assay targeting cox1 gene for the detection of Clonorchis sinensis in human fecal samples.

PubMed

Rahman, S M Mazidur; Song, Hyun Beom; Jin, Yan; Oh, Jin-Kyoung; Lim, Min Kyung; Hong, Sung-Tae; Choi, Min-Ho

2017-10-01

Clonorchiasis is prevalent in the Far East, and a major health problem in endemic areas. Infected persons may experience, if not treated, serious complications such as bile stone formation, pyogenic cholangitis, and even cholangiocarcinoma. Early diagnosis and treatment are important to prevent serious complications and, therefore, the simple and reliable diagnostic method is necessary to control clonorchiasis in endemic areas, where resources for the diagnosis are limited. The loop-mediated isothermal amplification (LAMP) assay has been applied for the detection of Clonorchis sinensis DNA. Six primers targeting eight locations on the cytochrome c oxidase subunit 1 gene of C. sinensis were designed for species-specific amplification using the LAMP assay. The LAMP assay was sensitive enough to detect as little as 100 fg of C. sinensis genomic DNA and the detection limit in 100 mg of stool was as low as one egg. The assay was highly specific because no cross-reactivity was observed with the DNA of other helminths, protozoa or Escherichia coli. Then, LAMP assay was applied to human fecal samples collected from an endemic area of clonorchiasis in Korea. Using samples showing consistent results by both Kato-Katz method and real-time PCR as reference standards, the LAMP assay showed 97.1% (95% CI, 90.1-99.2) of sensitivity and 100% (95% CI, 92.9-100) of specificity. In stool samples with more than 100 eggs per gram of feces, the sensitivity achieved 100%. To detect C. sinensis in human fecal samples, the LAMP assay was applied and achieved high sensitivity and specificity. The LAMP assay can be utilized in field laboratories as a powerful tool for diagnosis and epidemiological survey of clonorchiasis.

Screening for prenatal substance use: development of the Substance Use Risk Profile-Pregnancy scale.

PubMed

Yonkers, Kimberly A; Gotman, Nathan; Kershaw, Trace; Forray, Ariadna; Howell, Heather B; Rounsaville, Bruce J

2010-10-01

To report on the development of a questionnaire to screen for hazardous substance use in pregnant women and to compare the performance of the questionnaire with other drug and alcohol measures. Pregnant women were administered a modified TWEAK (Tolerance, Worried, Eye-openers, Amnesia, K[C] Cut Down) questionnaire, the 4Ps Plus questionnaire, items from the Addiction Severity Index, and two questions about domestic violence (N=2,684). The sample was divided into "training" (n=1,610) and "validation" (n=1,074) subsamples. We applied recursive partitioning class analysis to the responses from individuals in the training subsample that resulted in a three-item Substance Use Risk Profile-Pregnancy scale. We examined sensitivity, specificity, and the fit of logistic regression models in the validation subsample to compare the performance of the Substance Use Risk Profile-Pregnancy scale with the modified TWEAK and various scoring algorithms of the 4Ps. The Substance Use Risk Profile-Pregnancy scale is comprised of three informative questions that can be scored for high- or low-risk populations. The Substance Use Risk Profile-Pregnancy scale algorithm for low-risk populations was mostly highly predictive of substance use in the validation subsample (Akaike's Information Criterion=579.75, Nagelkerke R=0.27) with high sensitivity (91%) and adequate specificity (67%). The high-risk algorithm had lower sensitivity (57%) but higher specificity (88%). The Substance Use Risk Profile-Pregnancy scale is simple and flexible with good sensitivity and specificity. The Substance Use Risk Profile-Pregnancy scale can potentially detect a range of substances that may be abused. Clinicians need to further assess women with a positive screen to identify those who require treatment for alcohol or illicit substance use in pregnancy. III.

The link between CD8⁺ T-cell antigen-sensitivity and HIV-suppressive capacity depends on HLA restriction, target epitope and viral isolate.

PubMed

Lissina, Anna; Fastenackels, Solène; Inglesias, Maria C; Ladell, Kristin; McLaren, James E; Briceño, Olivia; Gostick, Emma; Papagno, Laura; Autran, Brigitte; Sauce, Delphine; Price, David A; Saez-Cirion, Asier; Appay, Victor

2014-02-20

Although it is established that CD8 T-cell immunity is critical for the control of HIV replication in vivo, the key factors that determine antiviral efficacy are yet to be fully elucidated. Antigen-sensitivity and T-cell receptor (TCR) avidity have been identified as potential determinants of CD8⁺ T-cell efficacy. However, there is no general consensus in this regard because the relationship between these parameters and the control of HIV infection has been established primarily in the context of immunodominant CD8⁺ T-cell responses against the Gag₂₆₃₋₂₇₂ KK10 epitope restricted by human leukocyte antigen (HLA)-B27. To investigate the relationship between antigen-sensitivity, TCR avidity and HIV-suppressive capacity in vitro across epitope specificities and HLA class I restriction elements, we used a variety of techniques to study CD8⁺ T-cell clones specific for Nef₇₃₋₈₂ QK10 and Gag₂₀₋₂₉ RY10, both restricted by HLA-A3, alongside CD8⁺ T-cell clones specific for Gag₂₆₃₋₂₇₂ KK10. For each targeted epitope, the linked parameters of antigen-sensitivity and TCR avidity correlated directly with antiviral efficacy. However, marked differences in HIV-suppressive capacity were observed between epitope specificities, HLA class I restriction elements and viral isolates. Collectively, these data emphasize the central role of the TCR as a determinant of CD8⁺ T-cell efficacy and demonstrate that the complexities of antigen recognition across epitope and HLA class I boundaries can confound simple relationships between TCR engagement and HIV suppression.

Risk assessment using a novel score to predict anastomotic leak and major complications after oesophageal resection.

PubMed

Noble, Fergus; Curtis, Nathan; Harris, Scott; Kelly, Jamie J; Bailey, Ian S; Byrne, James P; Underwood, Timothy J

2012-06-01

Oesophagectomy is associated with significant morbidity and mortality. A simple score to define a patient's risk of developing major complications would be beneficial. Patients who underwent upper gastrointestinal resections with an oesophageal anastomosis between 2005 and 2010 were reviewed and formed the development dataset with resections performed in 2011 forming a prospective validation dataset. The association between post-operative C-reactive protein (CRP), white cell count (WCC) and albumin levels with anastomotic leak (AL) or major complication including death using the Clavien-Dindo (CD) classification were analysed by receiver operating characteristic curves. After multivariate analysis, from the development dataset, these factors were combined to create a novel score which was subsequently tested on the validation dataset. Two hundred fifty-eight patients were assessed to develop the score. Sixty-three patients (25%) developed a major complication, and there were seven (2.7%) in-patient deaths. Twenty-six (10%) patients were diagnosed with AL at median post-operative day 7 (range: 5-15). CRP (p = 0.002), WCC (p < 0.0001) and albumin (p = 0.001) were predictors of AL. Combining these markers improved prediction of AL (NUn score > 10: sensitivity 95%, specificity 49%, diagnostic accuracy 0.801 (95% confidence interval: 0.692-0.909, p < 0.0001)). The validation dataset confirmed these findings (NUn score > 10: sensitivity 100%, specificity 57%, diagnostic accuracy 0.879 (95% CI 0.763-0.994, p = 0.014)) and a major complication or death (NUn > 10: sensitivity 89%, specificity 63%, diagnostic accuracy 0.856 (95% CI 0.709-1, p = 0.001)). Blood-borne markers of the systemic inflammatory response are predictors of AL and major complications after oesophageal resection. When combined they may categorise a patient's risk of developing a serious complication with higher sensitivity and specificity.

Screening for Prenatal Substance Use

PubMed Central

Yonkers, Kimberly A.; Gotman, Nathan; Kershaw, Trace; Forray, Ariadna; Howell, Heather B.; Rounsaville, Bruce J.

2011-01-01

OBJECTIVE To report on the development of a questionnaire to screen for hazardous substance use in pregnant women and to compare the performance of the questionnaire with other drug and alcohol measures. METHODS Pregnant women were administered a modified TWEAK (Tolerance, Worried, Eye-openers, Amnesia, K[C] Cut Down) questionnaire, the 4Ps Plus questionnaire, items from the Addiction Severity Index, and two questions about domestic violence (N=2,684). The sample was divided into “training” (n=1,610) and “validation” (n=1,074) subsamples. We applied recursive partitioning class analysis to the responses from individuals in the training subsample that resulted in a three-item Substance Use Risk Profile-Pregnancy scale. We examined sensitivity, specificity, and the fit of logistic regression models in the validation subsample to compare the performance of the Substance Use Risk Profile-Pregnancy scale with the modified TWEAK and various scoring algorithms of the 4Ps. RESULTS The Substance Use Risk Profile-Pregnancy scale is comprised of three informative questions that can be scored for high- or low-risk populations. The Substance Use Risk Profile-Pregnancy scale algorithm for low-risk populations was mostly highly predictive of substance use in the validation subsample (Akaike’s Information Criterion=579.75, Nagelkerke R2=0.27) with high sensitivity (91%) and adequate specificity (67%). The high-risk algorithm had lower sensitivity (57%) but higher specificity (88%). CONCLUSION The Substance Use Risk Profile-Pregnancy scale is simple and flexible with good sensitivity and specificity. The Substance Use Risk Profile-Pregnancy scale can potentially detect a range of substances that may be abused. Clinicians need to further assess women with a positive screen to identify those who require treatment for alcohol or illicit substance use in pregnancy. PMID:20859145

Breakdown of Spatial Parallel Coding in Children's Drawing

ERIC Educational Resources Information Center

De Bruyn, Bart; Davis, Alyson

2005-01-01

When drawing real scenes or copying simple geometric figures young children are highly sensitive to parallel cues and use them effectively. However, this sensitivity can break down in surprisingly simple tasks such as copying a single line where robust directional errors occur despite the presence of parallel cues. Before we can conclude that this…

Development of a Highly Sensitive Nested-PCR Procedure Using a Single Closed Tube for Detection of Erwinia amylovora in Asymptomatic Plant Material

PubMed Central

Llop, Pablo; Bonaterra, Anna; Peñalver, Javier; López, María M.

2000-01-01

A novel method, which involves a nested PCR in a single closed tube, was developed for the sensitive detection of Erwinia amylovora in plant material. The external and internal primer pairs used had different annealing temperatures and directed the amplification of a specific DNA fragment from plasmid pEA29. The procedure involved two consecutive PCRs, the first of which was performed at a higher annealing temperature that allowed amplification only by the external primer pair. Using pure cultures of E. amylovora, the sensitivity of the nested PCR in one tube was similar to that of a standard nested PCR in two tubes. The specificity and sensitivity were greater than those of standard PCR procedures that used a single primer pair. The presence of inhibitors in plant material, very common in E. amylovora hosts, is overcome with this system in combination with a simple DNA extraction protocol because it eliminates many of the inhibitory compounds. In addition, it needs a very small sample volume (1 μl of DNA extracted). With 83 samples of naturally infected material, this method achieved better results than any other PCR technique: standard PCR detected 55% of positive samples, two-tube nested PCR detected 71% of positive samples, and nested PCR in a single closed tube detected 78% of positive samples. When analyzing asymptomatic plant material, the number of positive samples detected by the developed nested PCR was also the highest, compared with the PCR protocols indicated previously (17, 20, and 25% of 251 samples analyzed, respectively). This method is proposed for the detection of endophytic and epiphytic populations of E. amylovora in epidemiological studies and for routine use in quarantine surveys, due to its high sensitivity, specificity, speed, and simplicity. PMID:10788384

An ultrasensitive label-free biosensor for assaying of sequence-specific DNA-binding protein based on amplifying fluorescent conjugated polymer.

PubMed

Liu, Xingfen; Ouyang, Lan; Cai, Xiaohui; Huang, Yanqin; Feng, Xiaomiao; Fan, Quli; Huang, Wei

2013-03-15

Sensitive, reliable, and simple detection of sequence-specific DNA-binding proteins (DBP) is of paramount importance in the area of proteomics, genomics, and biomedicine. We describe herein a novel fluorescent-amplified strategy for ultrasensitive, visual, quantitative, and "turn-on" detection of DBP. A Förster resonance energy transfer (FRET) assay utilizing a cationic conjugated polymer (CCP) and an intercalating dye was designed to detect a key transcription factor, nuclear factor-kappa B (NF-κB), the model target. A series of label-free DNA probes bearing one or two protein-binding sites (PBS) were used to identify the target protein specifically. The binding DBP protects the probe from digestion by exonuclease III, resulting in high efficient FRET due to the high affinity between the intercalating dye and duplex DNA, as well as strong electrostatic interactions between the CCP and DNA probe. By using label-free hairpin DNA or double-stranded DNA containing two PBS as probe, we could detect as low as 1 pg/μL of NF-κB in HeLa nuclear extracts, which is 10000-fold more sensitive than the previously reported methods. The approach also allows naked-eye detection by observing fluorescent color of solutions with the assistance of a hand-held UV lamp. Additionally, a less than 10% relative standard deviation was obtained, which offers a new platform for superior precision, low-cost, and simple detection of DBP. The features of our optical biosensor shows promising potential for early diagnosis of many diseases and high-throughput screening of new drugs targeted to DNA-binding proteins. Copyright © 2012 Elsevier B.V. All rights reserved.

Treatment default amongst patients with tuberculosis in urban Morocco: predicting and explaining default and post-default sputum smear and drug susceptibility results.

PubMed

Cherkaoui, Imad; Sabouni, Radia; Ghali, Iraqi; Kizub, Darya; Billioux, Alexander C; Bennani, Kenza; Bourkadi, Jamal Eddine; Benmamoun, Abderrahmane; Lahlou, Ouafae; Aouad, Rajae El; Dooley, Kelly E

2014-01-01

Public tuberculosis (TB) clinics in urban Morocco. Explore risk factors for TB treatment default and develop a prediction tool. Assess consequences of default, specifically risk for transmission or development of drug resistance. Case-control study comparing patients who defaulted from TB treatment and patients who completed it using quantitative methods and open-ended questions. Results were interpreted in light of health professionals' perspectives from a parallel study. A predictive model and simple tool to identify patients at high risk of default were developed. Sputum from cases with pulmonary TB was collected for smear and drug susceptibility testing. 91 cases and 186 controls enrolled. Independent risk factors for default included current smoking, retreatment, work interference with adherence, daily directly observed therapy, side effects, quick symptom resolution, and not knowing one's treatment duration. Age >50 years, never smoking, and having friends who knew one's diagnosis were protective. A simple scoring tool incorporating these factors was 82.4% sensitive and 87.6% specific for predicting default in this population. Clinicians and patients described additional contributors to default and suggested locally-relevant intervention targets. Among 89 cases with pulmonary TB, 71% had sputum that was smear positive for TB. Drug resistance was rare. The causes of default from TB treatment were explored through synthesis of qualitative and quantitative data from patients and health professionals. A scoring tool with high sensitivity and specificity to predict default was developed. Prospective evaluation of this tool coupled with targeted interventions based on our findings is warranted. Of note, the risk of TB transmission from patients who default treatment to others is likely to be high. The commonly-feared risk of drug resistance, though, may be low; a larger study is required to confirm these findings.

Assessment of clinical analytical sensitivity and specificity of next-generation sequencing for detection of simple and complex mutations.

PubMed

Chin, Ephrem L H; da Silva, Cristina; Hegde, Madhuri

2013-02-19

Detecting mutations in disease genes by full gene sequence analysis is common in clinical diagnostic laboratories. Sanger dideoxy terminator sequencing allows for rapid development and implementation of sequencing assays in the clinical laboratory, but it has limited throughput, and due to cost constraints, only allows analysis of one or at most a few genes in a patient. Next-generation sequencing (NGS), on the other hand, has evolved rapidly, although to date it has mainly been used for large-scale genome sequencing projects and is beginning to be used in the clinical diagnostic testing. One advantage of NGS is that many genes can be analyzed easily at the same time, allowing for mutation detection when there are many possible causative genes for a specific phenotype. In addition, regions of a gene typically not tested for mutations, like deep intronic and promoter mutations, can also be detected. Here we use 20 previously characterized Sanger-sequenced positive controls in disease-causing genes to demonstrate the utility of NGS in a clinical setting using standard PCR based amplification to assess the analytical sensitivity and specificity of the technology for detecting all previously characterized changes (mutations and benign SNPs). The positive controls chosen for validation range from simple substitution mutations to complex deletion and insertion mutations occurring in autosomal dominant and recessive disorders. The NGS data was 100% concordant with the Sanger sequencing data identifying all 119 previously identified changes in the 20 samples. We have demonstrated that NGS technology is ready to be deployed in clinical laboratories. However, NGS and associated technologies are evolving, and clinical laboratories will need to invest significantly in staff and infrastructure to build the necessary foundation for success.

Quality assurance for high dose rate brachytherapy treatment planning optimization: using a simple optimization to verify a complex optimization

NASA Astrophysics Data System (ADS)

Deufel, Christopher L.; Furutani, Keith M.

2014-02-01

As dose optimization for high dose rate brachytherapy becomes more complex, it becomes increasingly important to have a means of verifying that optimization results are reasonable. A method is presented for using a simple optimization as quality assurance for the more complex optimization algorithms typically found in commercial brachytherapy treatment planning systems. Quality assurance tests may be performed during commissioning, at regular intervals, and/or on a patient specific basis. A simple optimization method is provided that optimizes conformal target coverage using an exact, variance-based, algebraic approach. Metrics such as dose volume histogram, conformality index, and total reference air kerma agree closely between simple and complex optimizations for breast, cervix, prostate, and planar applicators. The simple optimization is shown to be a sensitive measure for identifying failures in a commercial treatment planning system that are possibly due to operator error or weaknesses in planning system optimization algorithms. Results from the simple optimization are surprisingly similar to the results from a more complex, commercial optimization for several clinical applications. This suggests that there are only modest gains to be made from making brachytherapy optimization more complex. The improvements expected from sophisticated linear optimizations, such as PARETO methods, will largely be in making systems more user friendly and efficient, rather than in finding dramatically better source strength distributions.

A microRNA detection system based on padlock probes and rolling circle amplification

PubMed Central

Jonstrup, Søren Peter; Koch, Jørn; Kjems, Jørgen

2006-01-01

The differential expression and the regulatory roles of microRNAs (miRNAs) are being studied intensively these years. Their minute size of only 19–24 nucleotides and strong sequence similarity among related species call for enhanced methods for reliable detection and quantification. Moreover, miRNA expression is generally restricted to a limited number of specific cells within an organism and therefore requires highly sensitive detection methods. Here we present a simple and reliable miRNA detection protocol based on padlock probes and rolling circle amplification. It can be performed without specialized equipment and is capable of measuring the content of specific miRNAs in a few nanograms of total RNA. PMID:16888321

A microRNA detection system based on padlock probes and rolling circle amplification.

PubMed

Jonstrup, Søren Peter; Koch, Jørn; Kjems, Jørgen

2006-09-01

The differential expression and the regulatory roles of microRNAs (miRNAs) are being studied intensively these years. Their minute size of only 19-24 nucleotides and strong sequence similarity among related species call for enhanced methods for reliable detection and quantification. Moreover, miRNA expression is generally restricted to a limited number of specific cells within an organism and therefore requires highly sensitive detection methods. Here we present a simple and reliable miRNA detection protocol based on padlock probes and rolling circle amplification. It can be performed without specialized equipment and is capable of measuring the content of specific miRNAs in a few nanograms of total RNA.

Evaluation of detection methods for Campylobacter infections among under-fives in Mwanza City, Tanzania.

PubMed

Mushi, Martha Fidelis; Paterno, Laurent; Tappe, Dennis; Deogratius, Anna Pendo; Seni, Jeremiah; Moremi, Nyambura; Mirambo, Mariam Mwijuma; Mshana, Stephen Eliatosha

2014-01-01

Campylobacter species are recognized as a major cause of acute gastroenteritis in humans throughout the world. The diagnosis is mainly based on stool culture. This study was done to evaluate the effectiveness of staining methods (Gram stain using 0.3% carbol fuchsin as counter stain and 1% carbol fuchsin direct stain) versus culture as the gold standard. A total of 300 children attending Bugando Medical Centre (BMC) and the Sekou Toure regional hospital with acute watery diarrhea were enrolled. Two sets of slides were prepared stained with 1% carbol fuchsin for 30 seconds first set, and the second set stained with Gram's stain using 0.3% carbol fuchsin as counter stain for five minutes. Concurrently, stool samples were inoculated on Preston Agar selective. Of 300 stool specimens, 14(4.7%) showed positive culture after 48 hours of incubation and 28 (9.3%) shows typical morphology of Campylobacter species by both Gram stain and direct stain. The sensitivity of the Gram stain using 0.3% carbol fuchsin as counter stain and 1% carbol fuchsin simple stain versus culture as gold standard was 64.3%, with a specificity of 93.4%. The positive predictive value and negative predictive value were 32.1% and 98.2% respectively. The detection of Campylobacter by 1% carbol fuchsin is simple, inexpensive, and fast, with both a high sensitivity and specificity. Laboratories in settings with high prevalence of campylobacteriosis and/or limited resources can employ 1% carbol fuchsin direct stain in detecting campylobacter infections.

Building a Natural Language Processing Tool to Identify Patients With High Clinical Suspicion for Kawasaki Disease from Emergency Department Notes.

PubMed

Doan, Son; Maehara, Cleo K; Chaparro, Juan D; Lu, Sisi; Liu, Ruiling; Graham, Amanda; Berry, Erika; Hsu, Chun-Nan; Kanegaye, John T; Lloyd, David D; Ohno-Machado, Lucila; Burns, Jane C; Tremoulet, Adriana H

2016-05-01

Delayed diagnosis of Kawasaki disease (KD) may lead to serious cardiac complications. We sought to create and test the performance of a natural language processing (NLP) tool, the KD-NLP, in the identification of emergency department (ED) patients for whom the diagnosis of KD should be considered. We developed an NLP tool that recognizes the KD diagnostic criteria based on standard clinical terms and medical word usage using 22 pediatric ED notes augmented by Unified Medical Language System vocabulary. With high suspicion for KD defined as fever and three or more KD clinical signs, KD-NLP was applied to 253 ED notes from children ultimately diagnosed with either KD or another febrile illness. We evaluated KD-NLP performance against ED notes manually reviewed by clinicians and compared the results to a simple keyword search. KD-NLP identified high-suspicion patients with a sensitivity of 93.6% and specificity of 77.5% compared to notes manually reviewed by clinicians. The tool outperformed a simple keyword search (sensitivity = 41.0%; specificity = 76.3%). KD-NLP showed comparable performance to clinician manual chart review for identification of pediatric ED patients with a high suspicion for KD. This tool could be incorporated into the ED electronic health record system to alert providers to consider the diagnosis of KD. KD-NLP could serve as a model for decision support for other conditions in the ED. © 2016 by the Society for Academic Emergency Medicine.

Integration of Cell Phone Imaging with Microchip ELISA to Detect Ovarian Cancer HE4 Biomarker in Urine at the Point-of-Care

PubMed Central

Wang, ShuQi; Zhao, Xiaohu; Khimji, Imran; Akbas, Ragip; Qiu, Weiliang; Edwards, Dale; Cramer, Daniel W.; Ye, Bin; Demirci, Utkan

2013-01-01

Ovarian cancer is asymptomatic at early stages and most patients present with advanced levels of disease. Lack of cost-effective methods that can achieve frequent, simple and non-invasive testing hinders early detection and causes high mortality in ovarian cancer patients. Here, we report a simple and inexpensive microchip ELISA-based detection module that employs a portable detection system, i.e., a cell phone/charge-coupled device (CCD) to quantify an ovarian cancer biomarker, HE4, in urine. Integration of a mobile application with a cell phone enabled immediate processing of microchip ELISA results, which eliminated the need for a bulky, expensive spectrophotometer. The HE4 level detected by a cell phone or a lensless CCD system was significantly elevated in urine samples from cancer patients (n = 19) than normal healthy controls (n = 20) (p < 0.001). Receiver operating characteristic (ROC) analyses showed that the microchip ELISA coupled with a cell phone running an automated analysis application had a sensitivity of 89.5% at a specificity of 90%. Under the same specificity, the microchip ELISA coupled with a CCD had a sensitivity of 84.2%. In conclusion, integration of microchip ELISA with cell phone/CCD-based colorimetric measurement technology can be used to detect HE4 biomarker at the point-of-care (POC), paving the way to create bedside technologies for diagnostics and treatment monitoring. PMID:21881677

A one-step multiplex RT-PCR assay for simultaneous detection of four viruses that infect peach.

PubMed

Yu, Y; Zhao, Z; Jiang, D; Wu, Z; Li, S

2013-10-01

A multiplex reverse transcription polymerase chain reaction (mRT-PCR) assay was developed to enable the simultaneous detection and differentiation of four viruses that infect peach, namely Apple chlorotic leaf spot virus (ACLSV), Cherry green ring mottle virus (CGRMV), Prunus necrotic ringspot virus (PNRSV) and Apricot pseudo-chlorotic leaf spot virus (APCLSV). In this study, four pairs of primers, one specific for each virus, were designed; the corresponding PCR products were 632, 439, 346 and 282 bp in length for ACLSV, CGRMV, PNRSV and APCLSV, respectively, and the fragments could be distinguished clearly by agarose gel electrophoresis. The sensitivity and specificity of the method were tested using individual RT-PCR and enzyme-linked immunosorbent assay (ELISA), and the identity of the RT-PCR amplification products was also confirmed by DNA sequencing. The results of RT-PCR and ELISA, along with batch detection using samples collected from peach orchards, revealed that this rapid and simple technique is an effective way to identify the four viruses simultaneously. The mRT-PCR assay described in this study was developed for the simultaneous detection of four peach viruses from infected peach samples is reliable and sensitive. In contrast to conventional uniplex RT-PCR, mRT-PCR is more efficient, reducing costs, time and handling when testing large numbers of samples. This rapid and simple method is useful for large-scale surveys of viruses that infect peach. © 2013 The Society for Applied Microbiology.

Trypanosomatidae: Phytomonas detection in plants and phytophagous insects by PCR amplification of a genus-specific sequence of the spliced leader gene.

PubMed

Serrano, M G; Nunes, L R; Campaner, M; Buck, G A; Camargo, E P; Teixeira, M M

1999-03-01

In this paper we describe a method for the detection of Phytomonas spp. from plants and phytophagous insects using the PCR technique by targeting a genus-specific sequence of the spliced leader (SL) gene. PCR amplification of DNA from 48 plant and insect isolates previously classified as Phytomonas by morphological, biochemical, and molecular criteria resulted in all cases in a 100-bp fragment that hybridized with the Phytomonas-specific spliced leader-derived probe SL3'. Moreover, this Phytomonas-specific PCR could also detect Phytomonas spp. in crude preparations of naturally infected plants and insects. This method shows no reaction with any other trypanosomatid genera or with plant and insect host DNA, revealing it to be able to detect Phytomonas spp. from fruit, latex, or phloem of various host plants as well as from salivary glands and digestive tubes of several species of insect hosts. Results demonstrated that SLPCR is a simple, fast, specific, and sensitive method that can be applied to the diagnosis of Phytomonas among cultured trypanosomatids and directly in plants and putative vector insects. Therefore, the method was shown to be a very specific and sensitive tool for diagnosis of Phytomonas without the need for isolation, culture, and DNA extraction of flagellates, a feature that is very convenient for practical and epidemiological purposes. Copyright 1999 Academic Press.

Evaluation of an existing screening tool for psoriatic arthritis in people with psoriasis and the development of a new instrument: the Psoriasis Epidemiology Screening Tool (PEST) questionnaire.

PubMed

Ibrahim, G H; Buch, M H; Lawson, C; Waxman, R; Helliwell, P S

2009-01-01

To evaluate an existing tool (the Swedish modification of the Psoriasis Assessment Questionnaire) and to develop a new instrument to screen for psoriatic arthritis in people with psoriasis. The starting point was a community-based survey of people with psoriasis using questionnaires developed from the literature. Selected respondents were examined and additional known cases of psoriatic arthritis were included in the analysis. The new instrument was developed using univariate statistics and a logistic regression model, comparing people with and without psoriatic arthritis. The instruments were compared using receiver operating curve (ROC) curve analysis. 168 questionnaires were returned (response rate 27%) and 93 people attended for examination (55% of questionnaire respondents). Of these 93, twelve were newly diagnosed with psoriatic arthritis during this study. These 12 were supplemented by 21 people with known psoriatic arthritis. Just 5 questions were found to be significant predictors of psoriatic arthritis in this population. Figures for sensitivity and specificity were 0.92 and 0.78 respectively, an improvement on the Alenius tool (sensitivity and specificity, 0.63 and 0.72 respectively). A new screening tool for identifying people with psoriatic arthritis has been developed. Five simple questions demonstrated good sensitivity and specificity in this population but further validation is required.

Rapid detection of Mycobacterium tuberculosis and rifampicin resistance in extrapulmonary tuberculosis and sputum smear-negative pulmonary suspects using Xpert MTB/RIF.

PubMed

Ullah, Irfan; Javaid, Arshad; Masud, Haleema; Ali, Mazhar; Basit, Anila; Ahmad, Waqas; Younis, Faisal; Yasmin, Rehana; Khan, Afsar; Jabbar, Abdul; Husain, Masroor; Butt, Zahid Ahmad

2017-04-01

Tuberculosis (TB) is a serious public health problem in developing countries such as Pakistan. Rapid diagnosis of TB and detection of drug resistance are very important for timely and appropriate management of multidrug-resistant TB (MDR-TB). The purpose of this study was to determine the diagnostic efficacy of the Xpert MTB/RIF assay for rapid diagnosis of TB and detection of rifampicin (RIF) resistance in extrapulmonary and smear-negative pulmonary TB suspects. A total of 98 bronchoalveolar lavage fluid (BALF) and 168 extrapulmonary specimens were processed by Xpert MTB/RIF. Culture results are considered as the gold standard for diagnosis of TB, and drug susceptibility testing for detection of RIF resistance. Diagnostic efficacy was measured in terms of sensitivity, specificity and positive and negative predictive values. The Xpert MTB/RIF assay detected 40 (40.8 %) of 98 BALF of presumptive pulmonary TB and 60 (35.7 %) of 168 extrapulmonary specimens. Sensitivity and specificity of the Xpert MTB/RIF assay for detection of TB was 86 and 88.4 %, respectively. The positive predictive value was 71.5 % while negative predictive value was 95.1 %. The Xpert MTB/RIF assay is a rapid and simple technique with high sensitivity and specificity for diagnosing TB and detecting drug resistance in extrapulmonary and smear-negative TB cases.

Building a Three-Dimensional Nano-Bio Interface for Aptasensing: An Analytical Methodology Based on Steric Hindrance Initiated Signal Amplification Effect.

PubMed

Du, Xiaojiao; Jiang, Ding; Hao, Nan; Qian, Jing; Dai, Liming; Zhou, Lei; Hu, Jianping; Wang, Kun

2016-10-04

The development of novel detection methodologies in electrochemiluminescence (ECL) aptasensor fields with simplicity and ultrasensitivity is essential for constructing biosensing architectures. Herein, a facile, specific, and sensitive methodology was developed unprecedentedly for quantitative detection of microcystin-LR (MC-LR) based on three-dimensional boron and nitrogen codoped graphene hydrogels (BN-GHs) assisted steric hindrance amplifying effect between the aptamer and target analytes. The recognition reaction was monitored by quartz crystal microbalance (QCM) to validate the possible steric hindrance effect. First, the BN-GHs were synthesized via self-assembled hydrothermal method and then applied as the Ru(bpy) 3 2+ immobilization platform for further loading the biomolecule aptamers due to their nanoporous structure and large specific surface area. Interestingly, we discovered for the first time that, without the aid of conventional double-stranded DNA configuration, such three-dimensional nanomaterials can directly amplify the steric hindrance effect between the aptamer and target analytes to a detectable level, and this facile methodology could be for an exquisite assay. With the MC-LR as a model, this novel ECL biosensor showed a high sensitivity and a wide linear range. This strategy supplies a simple and versatile platform for specific and sensitive determination of a wide range of aptamer-related targets, implying that three-dimensional nanomaterials would play a crucial role in engineering and developing novel detection methodologies for ECL aptasensing fields.

Use of the Sequential Organ Failure Assessment score for evaluating outcome among obstetric patients admitted to the intensive care unit.

PubMed

Jain, Shruti; Guleria, Kiran; Suneja, Amita; Vaid, Neelam B; Ahuja, Sharmila

2016-03-01

To evaluate the prognostic value of the Sequential Organ Failure Assessment (SOFA) score among obstetric patients admitted to the intensive care unit (ICU). A prospective study was conducted among 90 consecutive obstetric patients who were admitted to the ICU of Guru Teg Bahadur Hospital, Delhi, India, between October 6, 2010, and December 25, 2011. Maximum SOFA score was calculated for each of the six organ systems. Receiver operating characteristic curves were used to determine critical cutoff values for total, maximum total, and mean total SOFA scores at various time points. Total SOFA score at admission displayed an area under the curve (AUC) of 0.949, a cutoff value of at least 8.5, sensitivity of 86.7%, and specificity of 90.0%. Maximum total SOFA score had an AUC of 0.980, a cutoff value of at least 10.0, sensitivity of 96.7%, and specificity of 90.0%. Mean total SOFA score had an AUC of 0.997, a cutoff value of at least 9.0, sensitivity of 96.7%, and specificity of 96.7%. In terms of discriminatory power for predicting mortality among obstetric patients admitted to the ICU, total SOFA score at admission was the most relevant, simple, and accurate measure. Copyright © 2015 International Federation of Gynecology and Obstetrics. Published by Elsevier Ireland Ltd. All rights reserved.

Application of loop-mediated isothermal amplification (LAMP) assays for the detection of bovine herpesvirus 1.

PubMed

Socha, W; Rola, J; Urban-Chmiel, R; Żmudziński, J F

2017-09-26

Bovine herpesvirus-1 (BoHV-1), a causative agent of Infectious Bovine Rhinotracheitis (IBR), is responsible for high economic losses in cattle farming industry. The use of testing methods that allow early detection of BoHV-1-infected animals is a key element of each program of IBR eradication. The aim of the study was to design and evaluate two variants of LAMP isothermal tests with SYBR Green fluorescence probes, specific to the genes encoding gD and gE glycoproteins of BoHV-1. LAMP gE BoHV-1 assay was able to distinguish between gE- and gE+ strains of the virus. Both LAMP gD and gE assays were specific to BoHV-1 and did not react with other related to BoHV-1 alphaherpesviruses. Sensitivity of LAMP gD was 2x104 copies of the viral genome whereas for LAMP gE it was 2x105. Diagnostic sensitivity calculated for LAMP gD was 64.7% whereas for LAMP gE it was 80%. Diagnostic specificity for LAMP gD and LAMP gE was 78.9% and 89.3%, respectively. LAMP assay can be a rapid and simple method of diagnosis of acute BoHV-1 infections and discrimination of gE- strains. However, relatively low diagnostic sensitivity of the method can limit its use in routine diagnostics.

Rapid screening for inflammatory neuropathies by standardized clinical criteria

PubMed Central

Tramontozzi, Louis A.

2016-01-01

Abstract Background: Delay in recognition and treatment of inflammatory neuropathies increases morbidity and mortality. We have developed and standardized 3 clinical screening criteria that rapidly detect inflammatory neuropathies. Methods: We reviewed all patients with definite large fiber neuropathy in 2 different patient populations: 1 from a private neurology clinic and the other from a tertiary care center. Patients were divided into 2 groups: those with an inflammatory neuropathy and those with a noninflammatory neuropathy. We specifically noted the 3 key neuropathy characteristics: onset, distribution, and associated systemic features (ODS). We studied the sensitivity and specificity of ODS in differentiating between inflammatory and noninflammatory neuropathies. Results: A total of 206 patients were included: 51 from the private clinic and 155 from the tertiary care center. The sensitivity of using ODS in detecting an inflammatory neuropathy was 96% and the specificity was 85%. The positive predictive value of ODS was 0.8 and negative predictive value was 0.97. Conclusions: Rapid screening for inflammatory neuropathies by ODS clinical criteria is highly sensitive and has a high negative predictive value for noninflammatory neuropathies. ODS uses simple clinical criteria to rapidly screen for patients with a potentially treatable form of neuropathy and accelerate their diagnostic evaluation. Classification of evidence: This study provides Class IV evidence that 3 neuropathy characteristics—onset, distribution, and associated systemic features—accurately identify patients with inflammatory neuropathies. PMID:29443273

Adjusting for outcome misclassification: the importance of accounting for case-control sampling and other forms of outcome-related selection.

PubMed

Jurek, Anne M; Maldonado, George; Greenland, Sander

2013-03-01

Special care must be taken when adjusting for outcome misclassification in case-control data. Basic adjustment formulas using either sensitivity and specificity or predictive values (as with external validation data) do not account for the fact that controls are sampled from a much larger pool of potential controls. A parallel problem arises in surveys and cohort studies in which participation or loss is outcome related. We review this problem and provide simple methods to adjust for outcome misclassification in case-control studies, and illustrate the methods in a case-control birth certificate study of cleft lip/palate and maternal cigarette smoking during pregnancy. Adjustment formulas for outcome misclassification that ignore case-control sampling can yield severely biased results. In the data we examined, the magnitude of error caused by not accounting for sampling is small when population sensitivity and specificity are high, but increases as (1) population sensitivity decreases, (2) population specificity decreases, and (3) the magnitude of the differentiality increases. Failing to account for case-control sampling can result in an odds ratio adjusted for outcome misclassification that is either too high or too low. One needs to account for outcome-related selection (such as case-control sampling) when adjusting for outcome misclassification using external information. Copyright © 2013 Elsevier Inc. All rights reserved.

Creation of a simple natural language processing tool to support an imaging utilization quality dashboard.

PubMed

Swartz, Jordan; Koziatek, Christian; Theobald, Jason; Smith, Silas; Iturrate, Eduardo

2017-05-01

Testing for venous thromboembolism (VTE) is associated with cost and risk to patients (e.g. radiation). To assess the appropriateness of imaging utilization at the provider level, it is important to know that provider's diagnostic yield (percentage of tests positive for the diagnostic entity of interest). However, determining diagnostic yield typically requires either time-consuming, manual review of radiology reports or the use of complex and/or proprietary natural language processing software. The objectives of this study were twofold: 1) to develop and implement a simple, user-configurable, and open-source natural language processing tool to classify radiology reports with high accuracy and 2) to use the results of the tool to design a provider-specific VTE imaging dashboard, consisting of both utilization rate and diagnostic yield. Two physicians reviewed a training set of 400 lower extremity ultrasound (UTZ) and computed tomography pulmonary angiogram (CTPA) reports to understand the language used in VTE-positive and VTE-negative reports. The insights from this review informed the arguments to the five modifiable parameters of the NLP tool. A validation set of 2,000 studies was then independently classified by the reviewers and by the tool; the classifications were compared and the performance of the tool was calculated. The tool was highly accurate in classifying the presence and absence of VTE for both the UTZ (sensitivity 95.7%; 95% CI 91.5-99.8, specificity 100%; 95% CI 100-100) and CTPA reports (sensitivity 97.1%; 95% CI 94.3-99.9, specificity 98.6%; 95% CI 97.8-99.4). The diagnostic yield was then calculated at the individual provider level and the imaging dashboard was created. We have created a novel NLP tool designed for users without a background in computer programming, which has been used to classify venous thromboembolism reports with a high degree of accuracy. The tool is open-source and available for download at http://iturrate.com/simpleNLP. Results obtained using this tool can be applied to enhance quality by presenting information about utilization and yield to providers via an imaging dashboard. Copyright © 2017 Elsevier B.V. All rights reserved.

Sonographic Diagnosis of Tubal Cancer with IOTA Simple Rules Plus Pattern Recognition

PubMed Central

Tongsong, Theera; Wanapirak, Chanane; Tantipalakorn, Charuwan; Tinnangwattana, Dangcheewan

2017-01-01

Objective: To evaluate diagnostic performance of IOTA simple rules plus pattern recognition in predicting tubal cancer. Methods: Secondary analysis was performed on prospective database of our IOTA project. The patients recruited in the project were those who were scheduled for pelvic surgery due to adnexal masses. The patients underwent ultrasound examinations within 24 hours before surgery. On ultrasound examination, the masses were evaluated using the well-established IOTA simple rules plus pattern recognition (sausage-shaped appearance, incomplete septum, visible ipsilateral ovaries) to predict tubal cancer. The gold standard diagnosis was based on histological findings or operative findings. Results: A total of 482 patients, including 15 cases of tubal cancer, were evaluated by ultrasound preoperatively. The IOTA simple rules plus pattern recognition gave a sensitivity of 86.7% (13 in 15) and specificity of 97.4%. Sausage-shaped appearance was identified in nearly all cases (14 in 15). Incomplete septa and normal ovaries could be identified in 33.3% and 40%, respectively. Conclusion: IOTA simple rules plus pattern recognition is relatively effective in predicting tubal cancer. Thus, we propose the simple scheme in diagnosis of tubal cancer as follows. First of all, the adnexal masses are evaluated with IOTA simple rules. If the B-rules could be applied, tubal cancer is reliably excluded. If the M-rules could be applied or the result is inconclusive, careful delineation of the mass with pattern recognition should be performed. PMID:29172273

Sonographic Diagnosis of Tubal Cancer with IOTA Simple Rules Plus Pattern Recognition

PubMed

Tongsong, Theera; Wanapirak, Chanane; Tantipalakorn, Charuwan; Tinnangwattana, Dangcheewan

2017-11-26

Objective: To evaluate diagnostic performance of IOTA simple rules plus pattern recognition in predicting tubal cancer. Methods: Secondary analysis was performed on prospective database of our IOTA project. The patients recruited in the project were those who were scheduled for pelvic surgery due to adnexal masses. The patients underwent ultrasound examinations within 24 hours before surgery. On ultrasound examination, the masses were evaluated using the well-established IOTA simple rules plus pattern recognition (sausage-shaped appearance, incomplete septum, visible ipsilateral ovaries) to predict tubal cancer. The gold standard diagnosis was based on histological findings or operative findings. Results: A total of 482 patients, including 15 cases of tubal cancer, were evaluated by ultrasound preoperatively. The IOTA simple rules plus pattern recognition gave a sensitivity of 86.7% (13 in 15) and specificity of 97.4%. Sausage-shaped appearance was identified in nearly all cases (14 in 15). Incomplete septa and normal ovaries could be identified in 33.3% and 40%, respectively. Conclusion: IOTA simple rules plus pattern recognition is relatively effective in predicting tubal cancer. Thus, we propose the simple scheme in diagnosis of tubal cancer as follows. First of all, the adnexal masses are evaluated with IOTA simple rules. If the B-rules could be applied, tubal cancer is reliably excluded. If the M-rules could be applied or the result is inconclusive, careful delineation of the mass with pattern recognition should be performed. Creative Commons Attribution License

Utility of Water Siphon Maneuver for Eliciting Gastroesophageal Reflux During Barium Esophagography: Correlation With Histologic Findings.

PubMed

Dane, B; Doshi, A; Khan, A; Megibow, A

2018-06-12

The objective of this study is to evaluate whether the water siphon maneuver improves detection of gastroesophageal (GE) reflux during barium esophagography compared with observation for spontaneous reflux only. Histopathologic analysis is the reference standard. This retrospective study assessed 87 outpatients who underwent both barium esophagography and upper endoscopy-guided biopsy within a 30-day interval. The water siphon maneuver was routinely performed when spontaneous GE reflux was not observed during the fluoroscopic study. Radiology reports were reviewed for mentions of the presence of reflux and the circumstances in which it was observed (as a spontaneous occurrence or as a result of the water siphon maneuver). Pathology reports from subsequent endoscopic biopsies were reviewed to identify histologic changes of reflux disease. The sensitivity, specificity, and accuracy of esophagography, observation for spontaneous reflux, and the water siphon maneuver were calculated and then compared using a McNemar test. Of the 87 patients, 57 (65.5%) had GE reflux diagnosed on the basis of histologic changes noted on endoscopy, and 30 (34.5%) did not. A total of 57 patients (65.5%) showed reflux during esophagography, 41 (71.9%) of whom had reflux diagnosed by the water siphon maneuver, and 16 (28.1%) had reflux diagnosed on the basis of observation of spontaneous reflux. Forty-four patients had reflux diagnosed on the basis of both a barium study and histologic findings; 13 patients had reflux noted on esophagography but had negative histologic findings. The overall sensitivity, specificity, and accuracy of esophagography for reflux were 77.2%, 56.7%, and 70.1%, respectively. Spontaneous reflux alone had a sensitivity, specificity, and accuracy of 21.1%, 86.7%, and 43.7%, respectively. The water siphon maneuver showed a sensitivity of 71.1%, a specificity of 65.4%, and accuracy of 69.0%. The differences in the sensitivity, specificity, and accuracy of the water siphon maneuver versus observation of spontaneous reflux were statistically significant (p ≤ 0.004). A properly performed and interpreted water siphon maneuver significantly increases the sensitivity and accuracy for GE reflux during esophagography, compared with observation for spontaneous reflux alone. The water siphon maneuver is a simple addition to barium esophagography that improves sensitivity and accuracy for the diagnosis of GE reflux compared with observation alone.

Quantum-Dot-Based Electrochemical Immunoassay for High-Throughput Screening of the Prostate-Specific Antigen

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Jun; Liu, Guodong; Wu, Hong

2008-01-01

In this paper, we demonstrate an electrochemical high-throughput sensing platform for simple, sensitive detection of PSA based on QD labels. This sensing platform uses a microplate for immunoreactions and disposable screen-printed electrodes (SPE) for electrochemical stripping analysis of metal ions released from QD labels. With the 96-well microplate, capturing antibodies are conveniently immobilized to the well surface, and the process of immunoreaction is easily controlled. The formed sandwich complexes on the well surface are also easily isolated from reaction solutions. In particular, a microplate-based electrochemical assay can make it feasible to conduct a parallel analysis of several samples or multiplemore » protein markers. This assay offers a number of advantages including (1) simplicity, cost-effectiveness, (2) high sensitivity, (3) capability to sense multiple samples or targets in parallel, and (4) a potentially portable device with an SPE array implanted in the microplate. This PSA assay is sensitive because it uses two amplification processes: (1) QDs as a label for enhancing electrical signal since secondary antibodies are linked to QDs that contain a large number of metal atoms and (2) there is inherent signal amplification for electrochemical stripping analysis—preconcentration of metal ion onto the electrode surface for amplifying electrical signals. Therefore, the high sensitivity of this method, stemming from dual signal amplification via QD labels and pre-concentration, allows low concentration levels to be detected while using small sample volumes. Thus, this QD-based electrochemical detection approach offers a simple, rapid, cost-effective, and high throughput assay of PSA.« less

A portable smart-phone device for rapid and sensitive detection of E. coli O157:H7 in Yoghurt and Egg.

PubMed

Zeinhom, Mohamed Maarouf Ali; Wang, Yijia; Song, Yang; Zhu, Mei-Jun; Lin, Yuehe; Du, Dan

2018-01-15

The detection of E. coli O157:H7 in foods has held the attention of many researchers because of the seriousness attributed to this pathogen. In this study, we present a simple, sensitive, rapid and portable smartphone based fluorescence device for E. coli O157:H7 detection. This field-portable fluorescent imager on the smartphone involves a compact laser-diode-based photosource, a long-pass (LP) thin-film interference filter and a high-quality insert lenses. The design of the device provided a low noise to background imaging system. Based on a sandwich ELISA and the specific recognition of antibody to E. coli O157:H7, the sensitive detection of E. coli O157:H7 were realized both in standard samples and real matrix in yoghurt and egg on our device. The detection limit are 1 CFU/mL and 10 CFU/mL correspondingly. Recovery percentages of spiked yogurt and egg samples with 10 3 , 10 4 and 10 5 CFU/mL E. coli O157:H7 were 106.98, 96.52 and 102.65 (in yogurt) and 107.37, 105.64 and 93.84 (in egg) samples using our device, respectively. Most importantly, the entire process could be quickly completed within two hours. This smartphone based device provides a simple, rapid, sensitive detection platform for fluorescent imaging which applied in pathogen detection for food safety monitoring. Copyright © 2017 Elsevier B.V. All rights reserved.

Electrochemical sensor for glutathione detection based on mercury ion triggered hybridization chain reaction signal amplification.

PubMed

Wang, Yonghong; Jiang, Lun; Leng, Qinggang; Wu, Yaohui; He, Xiaoxiao; Wang, Kemin

2016-03-15

In this work, we design a new simple and highly sensitive strategy for electrochemical detection of glutathione (GSH) via mercury ion (Hg(2+)) triggered hybridization chain reaction (HCR) signal amplification. It is observed that in the absence of GSH, a specific thymine-Hg(2+)-thymine (T-Hg(2+)-T) coordination can fold into hairpin structures. While in the presence of GSH, it thus can be chelated with Hg(2+), resulting in Hg(2+) released from the T-Hg(2+)-T hairpin complex which then forms into ssDNA structure to further hybridize with the surface-immobilized capture DNA probe on the gold electrode with a sticky tail left. The presence of two hairpin helper probes through HCR leads to the formation of extended dsDNA superstructure on the electrode surface, which therefore causes the intercalation of numerous electroactive species ([Ru(NH3)6](3+)) into the dsDNA grooves, followed by a significantly amplified signal output whose intensity is related to the concentration of the GSH. Taking advantage of merits of enzyme-free amplification power of the HCR, the inherent high sensitivity of the electrochemical technique, and label-free detection which utilizes an electroactive species as a signaling molecule that binds to the anionic phosphate backbone of DNA strands via electrostatic force, not only does the proposed strategy enable sensitive detection of GSH, but show high selectivity against other amino acid, making our method a simple and sensitive addition to the amplified GSH detection. Copyright © 2015 Elsevier B.V. All rights reserved.

Evaluation of simple rapid HIV assays and development of national rapid HIV test algorithms in Dar es Salaam, Tanzania

PubMed Central

2009-01-01

Background Suitable algorithms based on a combination of two or more simple rapid HIV assays have been shown to have a diagnostic accuracy comparable to double enzyme-linked immunosorbent assay (ELISA) or double ELISA with Western Blot strategies. The aims of this study were to evaluate the performance of five simple rapid HIV assays using whole blood samples from HIV-infected patients, pregnant women, voluntary counseling and testing attendees and blood donors, and to formulate an alternative confirmatory strategy based on rapid HIV testing algorithms suitable for use in Tanzania. Methods Five rapid HIV assays: Determine™ HIV-1/2 (Inverness Medical), SD Bioline HIV 1/2 3.0 (Standard Diagnostics Inc.), First Response HIV Card 1–2.0 (PMC Medical India Pvt Ltd), HIV1/2 Stat-Pak Dipstick (Chembio Diagnostic System, Inc) and Uni-Gold™ HIV-1/2 (Trinity Biotech) were evaluated between June and September 2006 using 1433 whole blood samples from hospital patients, pregnant women, voluntary counseling and testing attendees and blood donors. All samples that were reactive on all or any of the five rapid assays and 10% of non-reactive samples were tested on a confirmatory Inno-Lia HIV I/II immunoblot assay (Immunogenetics). Results Three hundred and ninety samples were confirmed HIV-1 antibody positive, while 1043 were HIV negative. The sensitivity at initial testing of Determine, SD Bioline and Uni-Gold™ was 100% (95% CI; 99.1–100) while First Response and Stat-Pak had sensitivity of 99.5% (95% CI; 98.2–99.9) and 97.7% (95% CI; 95.7–98.9), respectively, which increased to 100% (95% CI; 99.1–100) on repeat testing. The initial specificity of the Uni-Gold™ assay was 100% (95% CI; 99.6–100) while specificities were 99.6% (95% CI; 99–99.9), 99.4% (95% CI; 98.8–99.7), 99.6% (95% CI; 99–99.9) and 99.8% (95% CI; 99.3–99.9) for Determine, SD Bioline, First Response and Stat-Pak assays, respectively. There was no any sample which was concordantly false positive in Uni-Gold™, Determine and SD Bioline assays. Conclusion An alternative confirmatory HIV testing strategy based on initial testing on either SD Bioline or Determine assays followed by testing of reactive samples on the Determine or SD Bioline gave 100% sensitivity (95% CI; 99.1–100) and 100% specificity (95% CI; 96–99.1) with Uni-Gold™ as tiebreaker for discordant results. PMID:19226452

Evaluation of simple rapid HIV assays and development of national rapid HIV test algorithms in Dar es Salaam, Tanzania.

PubMed

Lyamuya, Eligius F; Aboud, Said; Urassa, Willy K; Sufi, Jaffer; Mbwana, Judica; Ndugulile, Faustin; Massambu, Charles

2009-02-18

Suitable algorithms based on a combination of two or more simple rapid HIV assays have been shown to have a diagnostic accuracy comparable to double enzyme-linked immunosorbent assay (ELISA) or double ELISA with Western Blot strategies. The aims of this study were to evaluate the performance of five simple rapid HIV assays using whole blood samples from HIV-infected patients, pregnant women, voluntary counseling and testing attendees and blood donors, and to formulate an alternative confirmatory strategy based on rapid HIV testing algorithms suitable for use in Tanzania. Five rapid HIV assays: Determine HIV-1/2 (Inverness Medical), SD Bioline HIV 1/2 3.0 (Standard Diagnostics Inc.), First Response HIV Card 1-2.0 (PMC Medical India Pvt Ltd), HIV1/2 Stat-Pak Dipstick (Chembio Diagnostic System, Inc) and Uni-Gold HIV-1/2 (Trinity Biotech) were evaluated between June and September 2006 using 1433 whole blood samples from hospital patients, pregnant women, voluntary counseling and testing attendees and blood donors. All samples that were reactive on all or any of the five rapid assays and 10% of non-reactive samples were tested on a confirmatory Inno-Lia HIV I/II immunoblot assay (Immunogenetics). Three hundred and ninety samples were confirmed HIV-1 antibody positive, while 1043 were HIV negative. The sensitivity at initial testing of Determine, SD Bioline and Uni-Gold was 100% (95% CI; 99.1-100) while First Response and Stat-Pak had sensitivity of 99.5% (95% CI; 98.2-99.9) and 97.7% (95% CI; 95.7-98.9), respectively, which increased to 100% (95% CI; 99.1-100) on repeat testing. The initial specificity of the Uni-Gold assay was 100% (95% CI; 99.6-100) while specificities were 99.6% (95% CI; 99-99.9), 99.4% (95% CI; 98.8-99.7), 99.6% (95% CI; 99-99.9) and 99.8% (95% CI; 99.3-99.9) for Determine, SD Bioline, First Response and Stat-Pak assays, respectively. There was no any sample which was concordantly false positive in Uni-Gold, Determine and SD Bioline assays. An alternative confirmatory HIV testing strategy based on initial testing on either SD Bioline or Determine assays followed by testing of reactive samples on the Determine or SD Bioline gave 100% sensitivity (95% CI; 99.1-100) and 100% specificity (95% CI; 96-99.1) with Uni-Gold as tiebreaker for discordant results.

Towards more accurate HIV testing in sub-Saharan Africa: a multi-site evaluation of HIV RDTs and risk factors for false positives

PubMed Central

Kosack, Cara S; Page, Anne-Laure; Beelaert, Greet; Benson, Tumwesigye; Savane, Aboubacar; Ng’ang’a, Anne; Andre, Bita; Zahinda, Jean-Paul BN; Shanks, Leslie; Fransen, Katrien

2017-01-01

Abstract Introduction: Although individual HIV rapid diagnostic tests (RDTs) show good performance in evaluations conducted by WHO, reports from several African countries highlight potentially significant performance issues. Despite widespread use of RDTs for HIV diagnosis in resource-constrained settings, there has been no systematic, head-to-head evaluation of their accuracy with specimens from diverse settings across sub-Saharan Africa. We conducted a standardized, centralized evaluation of eight HIV RDTs and two simple confirmatory assays at a WHO collaborating centre for evaluation of HIV diagnostics using specimens from six sites in five sub-Saharan African countries. Methods: Specimens were transported to the Institute of Tropical Medicine (ITM), Antwerp, Belgium for testing. The tests were evaluated by comparing their results to a state-of-the-art reference algorithm to estimate sensitivity, specificity and predictive values. Results: 2785 samples collected from August 2011 to January 2015 were tested at ITM. All RDTs showed very high sensitivity, from 98.8% for First Response HIV Card Test 1–2.0 to 100% for Determine HIV 1/2, Genie Fast, SD Bioline HIV 1/2 3.0 and INSTI HIV-1/HIV-2 Antibody Test kit. Specificity ranged from 90.4% for First Response to 99.7% for HIV 1/2 STAT-PAK with wide variation based on the geographical origin of specimens. Multivariate analysis showed several factors were associated with false-positive results, including gender, provider-initiated testing and the geographical origin of specimens. For simple confirmatory assays, the total sensitivity and specificity was 100% and 98.8% for ImmunoComb II HIV 12 CombFirm (ImmunoComb) and 99.7% and 98.4% for Geenius HIV 1/2 with indeterminate rates of 8.9% and 9.4%. Conclusions: In this first systematic head-to-head evaluation of the most widely used RDTs, individual RDTs performed more poorly than in the WHO evaluations: only one test met the recommended thresholds for RDTs of ≥99% sensitivity and ≥98% specificity. By performing all tests in a centralized setting, we show that these differences in performance cannot be attributed to study procedure, end-user variation, storage conditions, or other methodological factors. These results highlight the existence of geographical and population differences in individual HIV RDT performance and underscore the challenges of designing locally validated algorithms that meet the latest WHO-recommended thresholds. PMID:28364560

Visual and highly sensitive detection of cancer cells by a colorimetric aptasensor based on cell-triggered cyclic enzymatic signal amplification.

PubMed

Zhang, Xianxia; Xiao, Kunyi; Cheng, Liwei; Chen, Hui; Liu, Baohong; Zhang, Song; Kong, Jilie

2014-06-03

Rapid and efficient detection of cancer cells at their earliest stages is one of the central challenges in cancer diagnostics. We developed a simple, cost-effective, and highly sensitive colorimetric method for visually detecting rare cancer cells based on cell-triggered cyclic enzymatic signal amplification (CTCESA). In the absence of target cells, hairpin aptamer probes (HAPs) and linker DNAs stably coexist in solution, and the linker DNA assembles DNA-AuNPs, producing a purple solution. In the presence of target cells, the specific binding of HAPs to the target cells triggers a conformational switch that results in linker DNA hybridization and cleavage by nicking endonuclease-strand scission cycles. Consequently, the cleaved fragments of linker DNA can no longer assemble into DNA-AuNPs, resulting in a red color. UV-vis spectrometry and photograph analyses demonstrated that this CTCESA-based method exhibited selective and sensitive colorimetric responses to the presence of target CCRF-CEM cells, which could be detected by the naked eye. The linear response for CCRF-CEM cells in a concentration range from 10(2) to 10(4) cells was obtained with a detection limit of 40 cells, which is approximately 20 times lower than the detection limit of normal AuNP-based methods without amplification. Given the high specificity and sensitivity of CTCESA, this colorimetric method provides a sensitive, label-free, and cost-effective approach for early cancer diagnosis and point-to-care applications.

Therapeutic Drug Monitoring of Phenytoin by Simple, Rapid, Accurate, Highly Sensitive and Novel Method and Its Clinical Applications.

PubMed

Shaikh, Abdul S; Guo, Ruichen

2017-01-01

Phenytoin has very challenging pharmacokinetic properties. To prevent its toxicity and ensure efficacy, continuous therapeutic monitoring is required. It is hard to get a simple, accurate, rapid, easily available, economical and highly sensitive assay in one method for therapeutic monitoring of phenytoin. The present study is directed towards establishing and validating a simpler, rapid, an accurate, highly sensitive, novel and environment friendly liquid chromatography/mass spectrometry (LC/MS) method for offering rapid and reliable TDM results of phenytoin in epileptic patients to physicians and clinicians for making immediate and rational decision. 27 epileptics patients with uncontrolled seizures or suspected of non-compliance or toxicity of phenytoin were selected and advised for TDM of phenytoin by neurologists of Qilu Hospital Jinan, China. The LC/MS assay was used for performing of therapeutic monitoring of phenytoin. The Agilent 1100 LC/MS system was used for TDM. The mixture of Ammonium acetate 5mM: Methanol at (35: 65 v/v) was used for the composition of mobile phase. The Diamonsil C18 (150mm×4.6mm, 5μm) column was used for the extraction of analytes in plasma. The samples were prepared with one step simple protein precipitation method. The technique was validated with the guidelines of International Conference on Harmonisation (ICH). The calibration curve demonstrated decent linearity within (0.2-20 µg/mL) concentration range with linearity equation, y= 0.0667855 x +0.00241785 and correlation coefficient (R2) of 0.99928. The specificity, recovery, linearity, accuracy, precision and stability results were within the accepted limits. The concentration of 0.2 µg/mL was observed as lower limit of quantitation (LLOQ), which is 12.5 times lower than the currently available enzyme-multiplied immunoassay technique (EMIT) for measurement of phenytoin in epilepsy patients. A rapid, simple, economical, precise, highly sensitive and novel LC/MS assay has been established, validated and applied successfully in TDM of 27 epileptics patients. It was alarmingly found that TDM results of all these patients were out of safe range except two patients. However, it needs further evaluation. Besides TDM, the stated method can also be applied in bioequivalence, pharmacokinetics, toxicokinetics and pharmacovigilance studies. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

Point of care diagnosis of multiple schistosome parasites: Species-specific DNA detection in urine by loop-mediated isothermal amplification (LAMP).

PubMed

Lodh, Nilanjan; Mikita, Kei; Bosompem, Kwabena M; Anyan, William K; Quartey, Joseph K; Otchere, Joseph; Shiff, Clive J

2017-09-01

Schistosomes are easily transmitted and high chance of repeat infection, so if control strategies based on targeted mass drug administration (MDA) are to succeed it is essential to have a test that is sensitive, accurate and simple to use. It is known and regularly demonstrated that praziquantel does not always eliminate an infection so in spite of the successes of control programs a residual of the reservoir survives to re-infect snails. The issue of diagnostic sensitivity becomes more critical in the assessment of program effectiveness. While serology, such as antigen capture tests might improve sensitivity, it has been shown that the presence of species-specific DNA fragments will indicate, most effectively, the presence of active parasites. Polymerase chain reaction (PCR) can amplify and detect DNA from urine residue captured on Whatman No. 3 filter paper that is dried after filtration. Previously we have detected S. mansoni and S. haematobium parasite-specific small repeat DNA fragment from filtered urine on filter paper by PCR. In the current study, we assessed the efficacy of detection of 86 urine samples for either or both schistosome parasites by PCR and loop-mediated isothermal amplification (LAMP) that were collected from a low to moderate transmission area in Ghana. Two different DNA extraction methods, standard extraction kit and field usable LAMP-PURE kit were also evaluated by PCR and LAMP amplification. With S. haematobium LAMP amplification for both extractions showed similar sensitivity and specificity when compared with PCR amplification (100%) verified by gel electrophoresis. For S. mansoni sensitivity was highest for LAMP amplification (100%) for standard extraction than PCR and LAMP with LAMP-PURE (99% and 94%). The LAMP-PURE extraction produced false negatives, which require further investigation for this field usable extraction kit. Overall high positive and negative predictive values (90% - 100%) for both species demonstrated a highly robust approach. The LAMP approach is close to point of care use and equally sensitive and specific to detection of species-specific DNA by PCR. LAMP can be an effective means to detect low intensity infection due to its simplicity and minimal DNA extraction requirement. This will enhance the effectiveness of surveillance and MDA control programs of schistosomiasis. Copyright © 2017 Elsevier B.V. All rights reserved.

Performance of C-reactive protein and procalcitonin to distinguish viral from bacterial and malarial causes of fever in Southeast Asia.

PubMed

Lubell, Yoel; Blacksell, Stuart D; Dunachie, Susanna; Tanganuchitcharnchai, Ampai; Althaus, Thomas; Watthanaworawit, Wanitda; Paris, Daniel H; Mayxay, Mayfong; Peto, Thomas J; Dondorp, Arjen M; White, Nicholas J; Day, Nicholas P J; Nosten, François; Newton, Paul N; Turner, Paul

2015-11-11

Poor targeting of antimicrobial drugs contributes to the millions of deaths each year from malaria, pneumonia, and other tropical infectious diseases. While malaria rapid diagnostic tests have improved use of antimalarial drugs, there are no similar tests to guide the use of antibiotics in undifferentiated fevers. In this study we estimate the diagnostic accuracy of two well established biomarkers of bacterial infection, procalcitonin and C-reactive protein (CRP) in discriminating between common viral and bacterial infections in malaria endemic settings of Southeast Asia. Serum procalcitonin and CRP levels were measured in stored serum samples from febrile patients enrolled in three prospective studies conducted in Cambodia, Laos and, Thailand. Of the 1372 patients with a microbiologically confirmed diagnosis, 1105 had a single viral, bacterial or malarial infection. Procalcitonin and CRP levels were compared amongst these aetiological groups and their sensitivity and specificity in distinguishing bacterial infections and bacteraemias from viral infections were estimated using standard thresholds. Serum concentrations of both biomarkers were significantly higher in bacterial infections and malaria than in viral infections. The AUROC for CRP in discriminating between bacterial and viral infections was 0.83 (0.81-0.86) compared with 0.74 (0.71-0.77) for procalcitonin (p < 0.0001). This relative advantage was evident in all sites and when stratifying patients by age and admission status. For CRP at a threshold of 10 mg/L, the sensitivity of detecting bacterial infections was 95% with a specificity of 49%. At a threshold of 20 mg/L sensitivity was 86% with a specificity of 67%. For procalcitonin at a low threshold of 0.1 ng/mL the sensitivity was 90% with a specificity of 39%. At a higher threshold of 0.5 ng/ul sensitivity was 60% with a specificity of 76%. In samples from febrile patients with mono-infections from rural settings in Southeast Asia, CRP was a highly sensitive and moderately specific biomarker for discriminating between viral and bacterial infections. Use of a CRP rapid test in peripheral health settings could potentially be a simple and affordable measure to better identify patients in need of antibacterial treatment and part of a global strategy to combat the emergence of antibiotic resistance.

Simple method for self-referenced and lable-free biosensing by using a capillary sensing element.

PubMed

Liu, Yun; Chen, Shimeng; Liu, Qiang; Liu, Zigeng; Wei, Peng

2017-05-15

We demonstrated a simple method for self-reference and label free biosensing based on a capillary sensing element and common optoelectronic devices. The capillary sensing element is illuminated by a light-emitting diode (LED) light source and detected by a webcam. Part of gold film that deposited on the tubing wall is functionalized to carry on the biological information in the excited SPR modes. The end face of the capillary was monitored and separate regions of interest (ROIs) were selected as the measurement channel and the reference channel. In the ROIs, the biological information can be accurately extracted from the image by simple image processing. Moreover, temperature fluctuation, bulk RI fluctuation, light source fluctuation and other factors can be effectively compensated during detection. Our biosensing device has a sensitivity of 1145%/RIU and a resolution better than 5.287 × 10 -4 RIU, considering a 0.79% noise level. We apply it for concanavalin A (Con A) biological measurement, which has an approximately linear response to the specific analyte concentration. This simple method provides a new approach for multichannel SPR sensing and reference-compensated calibration of SPR signal for label-free detection.

Development of a highly sensitive one-tube nested real-time PCR for detecting Mycobacterium tuberculosis.

PubMed

Choi, Yeonim; Jeon, Bo-Young; Shim, Tae Sun; Jin, Hyunwoo; Cho, Sang-Nae; Lee, Hyeyoung

2014-12-01

Rapid, accurate detection of Mycobacterium tuberculosis is crucial in the diagnosis of tuberculosis (TB), but conventional diagnostic methods have limited sensitivity and specificity or are time consuming. A new highly sensitive nucleic acid amplification test, combined nested and real-time polymerase chain reaction (PCR) in a single tube (one-tube nested real-time PCR), was developed for detecting M. tuberculosis, which takes advantage of two PCR techniques, i.e., nested PCR and real-time PCR. One-tube nested real-time PCR was designed to have two sequential reactions with two sets of primers and dual probes for the insertion sequence (IS) 6110 sequence of M. tuberculosis in a single closed tube. The minimum limits of detection of IS6110 real-time PCR and IS6110 one-tube nested real-time PCR were 100 fg/μL and 1 fg/μL of M. tuberculosis DNA, respectively. AdvanSure TB/non-tuberculous mycobacteria (NTM) real-time PCR, IS6110 real-time PCR, and two-tube nested real-time PCR showed 100% sensitivity and 100% specificity for clinical M. tuberculosis isolates and NTM isolates. In comparison, the sensitivities of AdvanSure TB/NTM real-time PCR, single IS6110 real-time PCR, and one-tube nested real-time PCR were 91% (152/167), 94.6% (158/167), and 100% (167/167) for sputum specimens, respectively. In conclusion, IS6110 one-tube nested real-time PCR is useful for detecting M. tuberculosis due to its high sensitivity and simple manipulation. Copyright © 2014 Elsevier Inc. All rights reserved.

A New Conjugation Method Used for the Development of an Immunoassay for the Detection of Amanitin, a Deadly Mushroom Toxin.

PubMed

Bever, Candace S; Barnych, Bogdan; Hnasko, Robert; Cheng, Luisa W; Stanker, Larry H

2018-06-28

One of the deadliest mushrooms is the death cap mushroom, Amanita phalloides . The most toxic constituent is α-amanitin, a bicyclic octapeptide, which damages the liver and kidneys. To develop a new tool for detecting this toxin, polyclonal antibodies were generated and characterized. Both α- and β-amanitin were coupled to carrier proteins through four different linking chemistries, one of which has never before been described. These conjugates were evaluated for their effectiveness in generating antibodies specific for the free toxin, as well as their utility in formatting heterogeneous assays with high sensitivity. Ultimately, these efforts yielded a newly described conjugation procedure utilizing periodate oxidation followed by reductive amination that successfully resulted in generating sensitive immunoassays (limit of detection (LOD), ~1.0 µg/L). The assays were characterized for their selectivity and were found to equally detect α-, β-, and γ-amanitin, and not cross-react with other toxins tested. Toxin detection in mushrooms was possible using a simple sample preparation method. This enzyme-linked immunosorbent assay (ELISA) is a simple and fast test, and readily detects amatoxins extracted from A. phalloides .

Development of loop-mediated isothermal amplification method for rapid detection of Streptococcus iniae, the causative agent of streptococcicosis in fish.

PubMed

Cai, Shuang-Hu; Wang, Bei; Lu, Yi-Shan; Jian, Ji-Chang; Wu, Zao-He

2012-04-01

Streptococcus iniae is a major pathogen that causes sever economic losses in tilapia aquaculture. A set of four specific primers was designed by targeting lctO gene. With Bst DNA polymerase, the target DNA can be clearly amplified for 60 min at 64 °C in a simple water bath. The sensitivity of the LAMP assay for the detection of S. iniae is about 12.4 cells per reaction in both of pure cultures and added fish tissues cultures. LAMP products could be judged with agar gel or naked eye after addition of SYBR Green I. There were no cross-reactions with other bacterial strains indicating high specificity of the LAMP. The LAMP method was also applied to detect S. iniae-infected tilapia tissues effectively. The LAMP assay reported here indicates the potential usefulness of the technique as a valuable simple, rapid alternative procedure for the detection of S. iniae during streptococcicosis monitoring of cultured fish. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Complex auditory behaviour emerges from simple reactive steering

NASA Astrophysics Data System (ADS)

Hedwig, Berthold; Poulet, James F. A.

2004-08-01

The recognition and localization of sound signals is fundamental to acoustic communication. Complex neural mechanisms are thought to underlie the processing of species-specific sound patterns even in animals with simple auditory pathways. In female crickets, which orient towards the male's calling song, current models propose pattern recognition mechanisms based on the temporal structure of the song. Furthermore, it is thought that localization is achieved by comparing the output of the left and right recognition networks, which then directs the female to the pattern that most closely resembles the species-specific song. Here we show, using a highly sensitive method for measuring the movements of female crickets, that when walking and flying each sound pulse of the communication signal releases a rapid steering response. Thus auditory orientation emerges from reactive motor responses to individual sound pulses. Although the reactive motor responses are not based on the song structure, a pattern recognition process may modulate the gain of the responses on a longer timescale. These findings are relevant to concepts of insect auditory behaviour and to the development of biologically inspired robots performing cricket-like auditory orientation.

A rapid and simple procedure to detect the presence of MVM in conditioned cell fluids or culture media.

PubMed

Chang, A; Havas, S; Borellini, F; Ostrove, J M; Bird, R E

1997-12-01

During the manufacture of biopharmaceuticals, numerous adventitious agents have been detected in Master Cell Banks, end-of-production cells as well as bulk harvest fluid. Recently, a number of large-scale production bioreactors have become infected with Minute Virus of Mice (MVM) during cGMP (current good manufacturing practices) operations, and this has resulted in both the loss of product and the need for major cleaning validation procedures to be put in place. We have developed a simple DNA extraction/PCR assay to detect the presence of MVM in cell culture supernatant (conditioned cell fluids). This highly specific assay can detect 10 or fewer genome equivalents (copies) of MVM following PCR and gel electrophoresis visualization. For routine high-throughput detection, 300-100 copies could be consistently detected. The extraction procedure was shown to reliably detect MVM at a concentration of 1 TCID50/ml. The combination of the extraction/PCR procedure establishes a powerful, sensitive, specific assay that can detect the presence of MVM sequences with a 1-day turnaround time.

Development of Loop-Mediated Isothermal Amplification (LAMP) Assay for Rapid Detection of Cannabis sativa.

PubMed

Kitamura, Masashi; Aragane, Masako; Nakamura, Kou; Watanabe, Kazuhito; Sasaki, Yohei

2016-07-01

In many parts of the world, the possession and cultivation of Cannabis sativa L. are restricted by law. As chemical or morphological analyses cannot identify the plant in some cases, a simple yet accurate DNA-based method for identifying C. sativa is desired. We have developed a loop-mediated isothermal amplification (LAMP) assay for the rapid identification of C. sativa. By optimizing the conditions for the LAMP reaction that targets a highly conserved region of tetrahydrocannabinolic acid (THCA) synthase gene, C. sativa was identified within 50 min at 60-66°C. The detection limit was the same as or higher than that of conventional PCR. The LAMP assay detected all 21 specimens of C. sativa, showing high specificity. Using a simple protocol, the identification of C. sativa could be accomplished within 90 min from sample treatment to detection without use of special equipment. A rapid, sensitive, highly specific, and convenient method for detecting and identifying C. sativa has been developed and is applicable to forensic investigations and industrial quality control.

Rapid and sensitive gas chromatography ion-trap mass spectrometry method for the determination of tobacco specific N-nitrosamines in secondhand smoke

DOE Office of Scientific and Technical Information (OSTI.GOV)

SLEIMAN, Mohamad; MADDALENA, Randy L.; GUNDEL, Lara A.

Tobacco-specific nitrosamines (TSNAs) are some of the most potent carcinogens in tobacco and cigarette smoke. Accurate quantification of these chemicals is needed to help assess public health risks. We developed and validated a specific and sensitive method to measure four TSNAs in both the gas- and particle-phase of secondhand smoke (SHS) using gas chromatography and ion-trap tandem mass spectrometry,. A smoking machine in an 18-m3 room-sized chamber generated relevant concentrations of SHS that were actively sampled on Teflon coated fiber glass (TCFG) filters, and passively sampled on cellulose substrates. A simple solid-liquid extraction protocol using methanol as solvent was successfullymore » applied to both filters with high recoveries ranging from 85 to 115percent. Tandem MS parameters were optimized to obtain the best sensitivity in terms of signal to-noise ratio (S/N) for the target compounds. For each TSNA, the major fragmentation pathways as well as ion structures were elucidated and compared with previously published data. The method showed excellent performances with a linear dynamic range between 2 and 1000 ng mL-1, low detection limits (S/N> 3) of 30-300 pg.ml-1 and precision with experimental errors below 10percent for all compounds. Moreover, no interfering peaks were observed indicating a high selectivity of MS/MS without the need for a sample clean up step. The sampling and analysis method provides a sensitive and accurate tool to detect and quantify traces of TSNA in SHS polluted indoor environments.« less

All-carbon suspended nanowire sensors as a rapid highly-sensitive label-free chemiresistive biosensing platform.

PubMed

Thiha, Aung; Ibrahim, Fatimah; Muniandy, Shalini; Dinshaw, Ignatius Julian; Teh, Swe Jyan; Thong, Kwai Lin; Leo, Bey Fen; Madou, Marc

2018-06-01

Nanowire sensors offer great potential as highly sensitive electrochemical and electronic biosensors because of their small size, high aspect ratios, and electronic properties. Nevertheless, the available methods to fabricate carbon nanowires in a controlled manner remain limited to expensive techniques. This paper presents a simple fabrication technique for sub-100 nm suspended carbon nanowire sensors by integrating electrospinning and photolithography techniques. Carbon Microelectromechanical Systems (C-MEMS) fabrication techniques allow fabrication of high aspect ratio carbon structures by patterning photoresist polymers into desired shapes and subsequent carbonization of resultant structures by pyrolysis. In our sensor platform, suspended nanowires were deposited by electrospinning while photolithography was used to fabricate support structures. We have achieved suspended carbon nanowires with sub-100 nm diameters in this study. The sensor platform was then integrated with a microfluidic chip to form a lab-on-chip device for label-free chemiresistive biosensing. We have investigated this nanoelectronics label-free biosensor's performance towards bacterial sensing by functionalization with Salmonella-specific aptamer probes. The device was tested with varying concentrations of Salmonella Typhimurium to evaluate sensitivity and various other bacteria to investigate specificity. The results showed that the sensor is highly specific and sensitive in detection of Salmonella with a detection limit of 10 CFU mL -1 . Moreover, this proposed chemiresistive assay has a reduced turnaround time of 5 min and sample volume requirement of 5 µL which are much less than reported in the literature. Copyright © 2018 Elsevier B.V. All rights reserved.

Electronic monitoring of treatment adherence and validation of alternative adherence measures in tuberculosis patients: a pilot study.

PubMed

van den Boogaard, Jossy; Lyimo, Ramsey A; Boeree, Martin J; Kibiki, Gibson S; Aarnoutse, Rob E

2011-09-01

To assess adherence to community-based directly observed treatment (DOT) among Tanzanian tuberculosis patients using the Medication Event Monitoring System (MEMS) and to validate alternative adherence measures for resource-limited settings using MEMS as a gold standard. This was a longitudinal pilot study of 50 patients recruited consecutively from one rural hospital, one urban hospital and two urban health centres. Treatment adherence was monitored with MEMS and the validity of the following adherence measures was assessed: isoniazid urine test, urine colour test, Morisky scale, Brief Medication Questionnaire, adapted AIDS Clinical Trials Group (ACTG) adherence questionnaire, pill counts and medication refill visits. The mean adherence rate in the study population was 96.3% (standard deviation, SD: 7.7). Adherence was less than 100% in 70% of the patients, less than 95% in 21% of them, and less than 80% in 2%. The ACTG adherence questionnaire and urine colour test had the highest sensitivities but lowest specificities. The Morisky scale and refill visits had the highest specificities but lowest sensitivities. Pill counts and refill visits combined, used in routine practice, yielded moderate sensitivity and specificity, but sensitivity improved when the ACTG adherence questionnaire was added. Patients on community-based DOT showed good adherence in this study. The combination of pill counts, refill visits and the ACTG adherence questionnaire could be used to monitor adherence in settings where MEMS is not affordable. The findings with regard to adherence and to the validity of simple adherence measures should be confirmed in larger populations with wider variability in adherence rates.

Development of a simplified urban water balance model (WABILA).

PubMed

Henrichs, M; Langner, J; Uhl, M

2016-01-01

During the last decade, water sensitive urban design (WSUD) has become more and more accepted. However, there is not any simple tool or option available to evaluate the influence of these measures on the local water balance. To counteract the impact of new settlements, planners focus on mitigating increases in runoff through installation of infiltration systems. This leads to an increasing non-natural groundwater recharge and decreased evapotranspiration. Simple software tools which evaluate or simulate the effect of WSUD on the local water balance are still needed. The authors developed a tool named WABILA (Wasserbilanz) that could support planners for optimal WSUD. WABILA is an easy-to-use planning tool that is based on simplified regression functions for established measures and land covers. Results show that WSUD has to be site-specific, based on climate conditions and the natural water balance.

Thermal comfort in Quebec City, Canada: sensitivity analysis of the UTCI and other popular thermal comfort indices in a mid-latitude continental city.

PubMed

Provençal, Simon; Bergeron, Onil; Leduc, Richard; Barrette, Nathalie

2016-04-01

The newly developed Universal Thermal Climate Index (UTCI), along with the physiological equivalent temperature (PET), the humidex (HX) and the wind chill index (WC), was calculated in Quebec City, Canada, a city with a strong seasonal climatic variability, over a 1-year period. The objective of this study is twofold: evaluate the operational benefits of implementing the UTCI for a climate monitoring program of public comfort and health awareness as opposed to relying on traditional and simple indices, and determine whether thermal comfort monitoring specific to dense urban neighborhoods is necessary to adequately fulfill the goals of the program. In order to do so, an analysis is performed to evaluate each of these indices' sensitivity to the meteorological variables that regulate them in different environments. Overall, the UTCI was found to be slightly more sensitive to mean radiant temperature, moderately more sensitive to humidity and much more sensitive to wind speed than the PET. This dynamic changed slightly depending on the environment and the season. In hot weather, the PET was found to be more sensitive to mean radiant temperature and therefore reached high values that could potentially be hazardous more frequently than the UTCI and the HX. In turn, the UTCI's stronger sensitivity to wind speed makes it a superior index to identify potentially hazardous weather in winter compared to the PET and the WC. Adopting the UTCI broadly would be an improvement over the traditionally popular HX and WC indices. The urban environment produced favorable conditions to sustain heat stress conditions, where the indices reached high values more frequently there than in suburban locations, which advocates for weather monitoring specific to denser urban areas.

Thermal comfort in Quebec City, Canada: sensitivity analysis of the UTCI and other popular thermal comfort indices in a mid-latitude continental city

NASA Astrophysics Data System (ADS)

Provençal, Simon; Bergeron, Onil; Leduc, Richard; Barrette, Nathalie

2016-04-01

The newly developed Universal Thermal Climate Index (UTCI), along with the physiological equivalent temperature (PET), the humidex (HX) and the wind chill index (WC), was calculated in Quebec City, Canada, a city with a strong seasonal climatic variability, over a 1-year period. The objective of this study is twofold: evaluate the operational benefits of implementing the UTCI for a climate monitoring program of public comfort and health awareness as opposed to relying on traditional and simple indices, and determine whether thermal comfort monitoring specific to dense urban neighborhoods is necessary to adequately fulfill the goals of the program. In order to do so, an analysis is performed to evaluate each of these indices' sensitivity to the meteorological variables that regulate them in different environments. Overall, the UTCI was found to be slightly more sensitive to mean radiant temperature, moderately more sensitive to humidity and much more sensitive to wind speed than the PET. This dynamic changed slightly depending on the environment and the season. In hot weather, the PET was found to be more sensitive to mean radiant temperature and therefore reached high values that could potentially be hazardous more frequently than the UTCI and the HX. In turn, the UTCI's stronger sensitivity to wind speed makes it a superior index to identify potentially hazardous weather in winter compared to the PET and the WC. Adopting the UTCI broadly would be an improvement over the traditionally popular HX and WC indices. The urban environment produced favorable conditions to sustain heat stress conditions, where the indices reached high values more frequently there than in suburban locations, which advocates for weather monitoring specific to denser urban areas.

Hydrocarbon sensors and materials therefor

DOEpatents

Pham, Ai Quoc; Glass, Robert S.

2000-01-01

An electrochemical hydrocarbon sensor and materials for use in sensors. A suitable proton conducting electrolyte and catalytic materials have been found for specific application in the detection and measurement of non-methane hydrocarbons. The sensor comprises a proton conducting electrolyte sandwiched between two electrodes. At least one of the electrodes is covered with a hydrocarbon decomposition catalyst. Two different modes of operation for the hydrocarbon sensors can be used: equilibrium versus non-equilibrium measurements and differential catalytic. The sensor has particular application for on-board monitoring of automobile exhaust gases to evaluate the performance of catalytic converters. In addition, the sensor can be utilized in monitoring any process where hydrocarbons are exhausted, for instance, industrial power plants. The sensor is low cost, rugged, sensitive, simple to fabricate, miniature, and does not suffer cross sensitivities.

Genetics-based methods for detection of Salmonella spp. in foods.

PubMed

Mozola, Mark A

2006-01-01

Genetic methods are now at the forefront of foodborne pathogen testing. The sensitivity, specificity, and inclusivity advantages offered by deoxyribonucleic acid (DNA) probe technology have driven an intense effort in methods development over the past 20 years. DNA probe-based methods for Salmonella spp. and other pathogens have progressed from time-consuming procedures involving the use of radioisotopes to simple, high throughput, automated assays. The analytical sensitivity of nucleic acid amplification technology has facilitated a reduction in analysis time by allowing enriched samples to be tested for previously undetectable quantities of analyte. This article will trace the evolution of the development of genetic methods for detection of Salmonella in foods, review the basic assay formats and their advantages and limitations, and discuss method performance characteristics and considerations for selection of methods.

Development of Nested PCR, Multiplex PCR, and Loop-Mediated Isothermal Amplification Assays for Rapid Detection of Cylindrocladium scoparium on Eucalyptus.

PubMed

Qiao, Tian-Min; Zhang, Jing; Li, Shu-Jiang; Han, Shan; Zhu, Tian-Hui

2016-10-01

Eucalyptus dieback disease, caused by Cylindrocladium scoparium , has occurred in last few years in large Eucalyptus planting areas in China and other countries. Rapid, simple, and reliable diagnostic techniques are desired for the early detection of Eucalyptus dieback of C. scoparium prior to formulation of efficient control plan. For this purpose, three PCR-based methods of nested PCR, multiplex PCR, loop-mediated isothermal amplification (LAMP) were developed for detection of C. scoparium based on factor 1-alpha (tef1) and beta-tubulin gene in this study. All of the three methods showed highly specific to C. scoparium . The sensitivities of the nested PCR and LAMP were much higher than the multiplex PCR. The sensitivity of multiplex PCR was also higher than regular PCR. C. scoparium could be detected within 60 min from infected Eucalyptus plants by LAMP, while at least 2 h was needed by the rest two methods. Using different Eucalyptus tissues as samples for C. scoparium detection, all of the three PCR-based methods showed much better detection results than regular PCR. Base on the results from this study, we concluded that any of the three PCR-based methods could be used as diagnostic technology for the development of efficient strategies of Eucalyptus dieback disease control. Particularly, LAMP was the most practical method in field application because of its one-step and rapid reaction, simple operation, single-tube utilization, and simple visualization of amplification products.

Development of Nested PCR, Multiplex PCR, and Loop-Mediated Isothermal Amplification Assays for Rapid Detection of Cylindrocladium scoparium on Eucalyptus

PubMed Central

Qiao, Tian-Min; Zhang, Jing; Li, Shu-Jiang; Han, Shan; Zhu, Tian-Hui

2016-01-01

Eucalyptus dieback disease, caused by Cylindrocladium scoparium, has occurred in last few years in large Eucalyptus planting areas in China and other countries. Rapid, simple, and reliable diagnostic techniques are desired for the early detection of Eucalyptus dieback of C. scoparium prior to formulation of efficient control plan. For this purpose, three PCR-based methods of nested PCR, multiplex PCR, loop-mediated isothermal amplification (LAMP) were developed for detection of C. scoparium based on factor 1-alpha (tef1) and beta-tubulin gene in this study. All of the three methods showed highly specific to C. scoparium. The sensitivities of the nested PCR and LAMP were much higher than the multiplex PCR. The sensitivity of multiplex PCR was also higher than regular PCR. C. scoparium could be detected within 60 min from infected Eucalyptus plants by LAMP, while at least 2 h was needed by the rest two methods. Using different Eucalyptus tissues as samples for C. scoparium detection, all of the three PCR-based methods showed much better detection results than regular PCR. Base on the results from this study, we concluded that any of the three PCR-based methods could be used as diagnostic technology for the development of efficient strategies of Eucalyptus dieback disease control. Particularly, LAMP was the most practical method in field application because of its one-step and rapid reaction, simple operation, single-tube utilization, and simple visualization of amplification products. PMID:27721691

Biochemical Detection and Identification False Alarm Rate Dependence on Wavelength Using Laser Induced Fluorescence

NASA Technical Reports Server (NTRS)

Bhartia, R.; Hug, W. F.; Sala, E. C.; Sijapati, K.; Lane, A. L.; Reid, R. D.; Conrad, P. G.

2006-01-01

Most organic and many inorganic materials absorb strongly in specific wavelength ranges in the deep UV between about 220nm and 300nm. Excitation within these absorption bands results in native fluorescence emission. Each compound or composite material, such as a bacterial spore, has a unique excitation-emission fingerprint that can be used to provide information about the material. The sensitivity and specificity with which these materials can be detected and identified depends on the excitation wavelength and the number and location of observation wavelengths.We will present data on our deep ultraviolet Targeted Ultraviolet Chemical Sensors that demonstrate the sensitivity and specificity of the sensors. In particular, we will demonstrate the ability to quantitatively differentiate a wide range of biochemical agent targets against a wide range of background materials. We will describe the relationship between spectral resolution and specificity in target identification, as well as simple, fast, algorithms to identify materials.Hand-held, battery operated instruments using a deep UV laser and multi-band detection have been developed and deployed on missions to the Antarctic, the Arctic, and the deep ocean with the capability of detecting a single bacterial spore and to differentiate a wide range of organic and biological compounds.

CSF levels of oligomeric alpha-synuclein and beta-amyloid as biomarkers for neurodegenerative disease

PubMed Central

Chatterjee, Gaurav; McGraw, Claire; Kasturirangan, Srinath; Schulz, Philip

2012-01-01

Protein misfolding and aggregation is a critically important feature in many devastating neurodegenerative diseases, therefore characterization of the CSF concentration profiles of selected key forms and morphologies of proteins involved in these diseases, including β-amyloid (Aβ) and α-synuclein (a-syn), can be an effective diagnostic assay for these diseases. CSF levels of tau and Aβ have been shown to have great promise as biomarkers for Alzheimer’s disease. However since the onset and progression of many neurodegenerative diseases have been strongly correlated with the presence of soluble oligomeric aggregates of proteins including various Aβ and a-syn aggregate species, specific detection and quantification of levels of each of these different toxic protein species in CSF may provide a simple and accurate means to presymptomatically diagnose and distinguish between these diseases. Here we show that the presence of different protein morphologies in human CSF samples can be readily detected using highly selective morphology specific reagents in conjunction with a sensitive electronic biosensor. We further show that these morphology specific reagents can readily distinguish between post-mortem CSF samples from AD, PD and cognitively normal sources. These studies suggest that detection of specific oligomeric aggregate species holds great promise as sensitive biomarkers for neurodegenerative disease. PMID:22076255

The use of measures of obesity in childhood for predicting obesity and the development of obesity-related diseases in adulthood: a systematic review and meta-analysis.

PubMed

Simmonds, Mark; Burch, Jane; Llewellyn, Alexis; Griffiths, Claire; Yang, Huiqin; Owen, Christopher; Duffy, Steven; Woolacott, Nerys

2015-06-01

It is uncertain which simple measures of childhood obesity are best for predicting future obesity-related health problems and the persistence of obesity into adolescence and adulthood. To investigate the ability of simple measures, such as body mass index (BMI), to predict the persistence of obesity from childhood into adulthood and to predict obesity-related adult morbidities. To investigate how accurately simple measures diagnose obesity in children, and how acceptable these measures are to children, carers and health professionals. Multiple sources including MEDLINE, EMBASE and The Cochrane Library were searched from 2008 to 2013. Systematic reviews and a meta-analysis were carried out of large cohort studies on the association between childhood obesity and adult obesity; the association between childhood obesity and obesity-related morbidities in adulthood; and the diagnostic accuracy of simple childhood obesity measures. Study quality was assessed using Quality Assessment of Diagnostic Accuracy Studies-2 (QUADAS-2) and a modified version of the Quality in Prognosis Studies (QUIPS) tool. A systematic review and an elicitation exercise were conducted on the acceptability of the simple measures. Thirty-seven studies (22 cohorts) were included in the review of prediction of adult morbidities. Twenty-three studies (16 cohorts) were included in the tracking review. All studies included BMI. There were very few studies of other measures. There was a strong positive association between high childhood BMI and adult obesity [odds ratio 5.21, 95% confidence interval (CI) 4.50 to 6.02]. A positive association was found between high childhood BMI and adult coronary heart disease, diabetes and a range of cancers, but not stroke or breast cancer. The predictive accuracy of childhood BMI to predict any adult morbidity was very low, with most morbidities occurring in adults who were of healthy weight in childhood. Predictive accuracy of childhood obesity was moderate for predicting adult obesity, with a sensitivity of 30% and a specificity of 98%. Persistence of obesity from adolescence to adulthood was high. Thirty-four studies were included in the diagnostic accuracy review. Most of the studies used the least reliable reference standard (dual-energy X-ray absorptiometry); only 24% of studies were of high quality. The sensitivity of BMI for diagnosing obesity and overweight varied considerably; specificity was less variable. Pooled sensitivity of BMI was 74% (95% CI 64.2% to 81.8%) and pooled specificity was 95% (95% CI 92.2% to 96.4%). The acceptability to children and their carers of BMI or other common simple measures was generally good. Little evidence was available regarding childhood measures other than BMI. No individual-level analysis could be performed. Childhood BMI is not a good predictor of adult obesity or adult disease; the majority of obese adults were not obese as children and most obesity-related adult morbidity occurs in adults who had a healthy childhood weight. However, obesity (as measured using BMI) was found to persist from childhood to adulthood, with most obese adolescents also being obese in adulthood. BMI was found to be reasonably good for diagnosing obesity during childhood. There is no convincing evidence suggesting that any simple measure is better than BMI for diagnosing obesity in childhood or predicting adult obesity and morbidity. Further research on obesity measures other than BMI is needed to determine which is the best tool for diagnosing childhood obesity, and new cohort studies are needed to investigate the impact of contemporary childhood obesity on adult obesity and obesity-related morbidities. This study is registered as PROSPERO CRD42013005711. The National Institute for Health Research Health Technology Assessment programme.

Dual sensitivity of inferior colliculus neurons to ITD in the envelopes of high-frequency sounds: experimental and modeling study

PubMed Central

Wang, Le; Devore, Sasha; Delgutte, Bertrand

2013-01-01

Human listeners are sensitive to interaural time differences (ITDs) in the envelopes of sounds, which can serve as a cue for sound localization. Many high-frequency neurons in the mammalian inferior colliculus (IC) are sensitive to envelope-ITDs of sinusoidally amplitude-modulated (SAM) sounds. Typically, envelope-ITD-sensitive IC neurons exhibit either peak-type sensitivity, discharging maximally at the same delay across frequencies, or trough-type sensitivity, discharging minimally at the same delay across frequencies, consistent with responses observed at the primary site of binaural interaction in the medial and lateral superior olives (MSO and LSO), respectively. However, some high-frequency IC neurons exhibit dual types of envelope-ITD sensitivity in their responses to SAM tones, that is, they exhibit peak-type sensitivity at some modulation frequencies and trough-type sensitivity at other frequencies. Here we show that high-frequency IC neurons in the unanesthetized rabbit can also exhibit dual types of envelope-ITD sensitivity in their responses to SAM noise. Such complex responses to SAM stimuli could be achieved by convergent inputs from MSO and LSO onto single IC neurons. We test this hypothesis by implementing a physiologically explicit, computational model of the binaural pathway. Specifically, we examined envelope-ITD sensitivity of a simple model IC neuron that receives convergent inputs from MSO and LSO model neurons. We show that dual envelope-ITD sensitivity emerges in the IC when convergent MSO and LSO inputs are differentially tuned for modulation frequency. PMID:24155013

Bioconjugated fluorescent silica nanoparticles for the rapid detection of Entamoeba histolytica.

PubMed

Hemadi, Ahmad; Ekrami, Alireza; Oormazdi, Hormozd; Meamar, Ahmad Reza; Akhlaghi, Lame; Samarbaf-Zadeh, Ali Reza; Razmjou, Elham

2015-05-01

Rapid detection of Entamoeba histolytica based on fluorescent silica nanoparticle (FSNP) indirect immunofluorescence microscopy was evaluated. Silica nanoparticles were synthesized using Stöber's method, with their surface activated to covalently bind to, and immobilize, protein A. For biolabeling, FSNP was added to conjugated E. histolytica trophozoites with monoclonal anti-E. histolytica IgG1 for microscopic observation of fluorescence. Fluorescent silica nanoparticle sensitivity was determined with axenically cultured E. histolytica serially diluted to seven concentrations. Specificity was evaluated using other intestinal protozoa. Fluorescent silica nanoparticles detected E. histolytica at the lowest tested concentration with no cross-reaction with Entamoeba dispar, Entamoeba moshkovskii, Blastocystis sp., or Giardia lamblia. Visualization of E. histolytica trophozoites with anti-E. histolytica antibody labeled with fluorescein isothiocyanate (FITC) was compared with that using anti-E. histolytica antibody bioconjugated FSNP. Although FITC and FSNP produced similar results, the amount of specific antibody required for FITC to induce fluorescence of similar intensity was fivefold that for FSNP. Fluorescent silica nanoparticles delivered a rapid, simple, cost-effective, and highly sensitive and specific method of detecting E. histolytica. Further study is needed before introducing FSNP for laboratory diagnosis of amoebiasis. Copyright © 2015 Elsevier B.V. All rights reserved.

Detection of Streptococcus pyogenes using rapid visual molecular assay.

PubMed

Zhao, Xiangna; He, Xiaoming; Li, Huan; Zhao, Jiangtao; Huang, Simo; Liu, Wei; Wei, Xiao; Ding, Yiwei; Wang, Zhaoyan; Zou, Dayang; Wang, Xuesong; Dong, Derong; Yang, Zhan; Yan, Xiabei; Huang, Liuyu; Du, Shuangkui; Yuan, Jing

2015-09-01

Streptococcus pyogenes is an increasingly important pathogen in many parts of the world. Rapid and accurate detection of S. pyogenes aids in the control of the infection. In this study, a loop-mediated isothermal amplification (LAMP) assay was developed and validated for the specific detection of S. pyogenes. The assay incorporates two methods: a chromogenic analysis using a calcein/Mn(2+) complex and real-time turbidity monitoring to assess the reaction. Both methods detected the target DNA within 60 min under 64°C isothermal conditions. The assay used specifically designed primers to target spy1258, and correctly identified 111 strains of S. pyogenes and 32 non-S. pyogenes strains, including other species of the genus Streptococcus. Tests using reference strains showed that the LAMP assay was highly specific. The sensitivity of the assay, with a detection limit of 1.49 pg DNA, was 10-fold greater than that of PCR. The LAMP assay established in this study is simple, fast and sensitive, and does not rely upon any special equipment; thus, it could be employed in clinical diagnosis. © FEMS 2015. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Development and evaluation of probe based real time loop mediated isothermal amplification for Salmonella: A new tool for DNA quantification.

PubMed

Mashooq, Mohmad; Kumar, Deepak; Niranjan, Ankush Kiran; Agarwal, Rajesh Kumar; Rathore, Rajesh

2016-07-01

A one step, single tube, accelerated probe based real time loop mediated isothermal amplification (RT LAMP) assay was developed for detecting the invasion gene (InvA) of Salmonella. The probe based RT LAMP is a novel method of gene amplification that amplifies nucleic acid with high specificity and rapidity under isothermal conditions with a set of six primers. The whole procedure is very simple and rapid, and amplification can be obtained in 20min. Detection of gene amplification was accomplished by amplification curve, turbidity and addition of DNA binding dye at the end of the reaction results in colour difference and can be visualized under normal day light and in UV. The sensitivity of developed assay was found 10 fold higher than taqman based qPCR. The specificity of the RT LAMP assay was validated by the absence of any cross reaction with other members of enterobacteriaceae family and other gram negative bacteria. These results indicate that the probe based RT LAMP assay is extremely rapid, cost effective, highly specific and sensitivity and has potential usefulness for rapid Salmonella surveillance. Crown Copyright © 2016. Published by Elsevier B.V. All rights reserved.

Photoresponses in Gold Nanoparticle Single-Electron Transistors with Molecular Floating Gates

NASA Astrophysics Data System (ADS)

Noguchi, Yutaka; Yamamoto, Makoto; Ishii, Hisao; Ueda, Rieko; Terui, Toshifumi; Imazu, Keisuke; Tamada, Kaoru; Sakano, Takeshi; Matsuda, Kenji

2013-11-01

We have proposed a simple method of activating advanced functions in single-electron transistors (SETs) based on the specific properties of individual molecules. As a prototype, we fabricated a copper phthalocyanine (CuPc)-doped SET. The device consists of a gold-nanoparticle (GNP)-based SET doped with CuPc as a photoresponsive floating gate. In this paper, we report the details of the photoresponses of the CuPc-doped SET, such as conductance switching, sensitivity to the wavelength of the incident light, and multiple induced states.

Comparison of growth inhibition and immunofluorescence tests in serotyping clinical isolates of Ureaplasma urealyticum.

PubMed Central

Piot, P

1977-01-01

Typestrains of the eight serotypes of Ureaplasma urealyticum and 39 genital isolates were typed by the growth inhibition (GI) and indirect immunofluorescence (IF) tests. The GI test proved to be very specific and simple, demanding large volumes of serum. It was less sensitive than the IF test, which produced more cross-reactions, was economical in serum, and able to detect mixed infections. Of the 39 isolates, 27 were serotyped by GI and 34 by IF. Mixed cultures occurred in as many as 36% of the isolates. PMID:326348

Controlling Disulfide Bond Formation and Crystal Growth from 2-Mercaptobenzoic Acid

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rowland, Clare E.; Cantos, P. M.; Toby, B. H.

2011-03-02

We report disulfide bond formation from 2-mercaptobenzoic acid (2-MBA) under hydrothermal conditions as a function of pH. Under acidic conditions, 2-MBA remains unchanged. Upon increasing pH, however, we observe 50% oxidation to 2,2'-disulfanediyldibenzoic acid (2,2'-DSBA), which is isolated as a cocrystal of both the thiol and disulfide molecules. At neutral pH, we observe complete oxidation and concurrent crystal growth. The pH sensitivity of this system allows targeting crystals of specific composition from simple building units through a straightforward pH manipulation.

Terahertz imaging through self-mixing in a quantum cascade laser.

PubMed

Dean, Paul; Lim, Yah Leng; Valavanis, Alex; Kliese, Russell; Nikolić, Milan; Khanna, Suraj P; Lachab, Mohammad; Indjin, Dragan; Ikonić, Zoran; Harrison, Paul; Rakić, Aleksandar D; Linfield, Edmund H; Davies, A Giles

2011-07-01

We demonstrate terahertz (THz) frequency imaging using a single quantum cascade laser (QCL) device for both generation and sensing of THz radiation. Detection is achieved by utilizing the effect of self-mixing in the THz QCL, and, specifically, by monitoring perturbations to the voltage across the QCL, induced by light reflected from an external object back into the laser cavity. Self-mixing imaging offers high sensitivity, a potentially fast response, and a simple, compact optical design, and we show that it can be used to obtain high-resolution reflection images of exemplar structures.

Label-free detection of specific DNA sequence-telomere using unmodified gold nanoparticles as colorimetric probes

NASA Astrophysics Data System (ADS)

Qi, Yingying; Li, Li; Li, Baoxin

2009-09-01

A simple and sensitive label-free colorimetric detection of telomere DNA has been developed. It was based on the color change of gold nanoparticles (AuNPs) due to DNA hybridization. UV-vis spectra and transmission electron microscopy (TEM) were used to investigate the change of AuNPs. Under the optimized conditions, the linear range for determination of telomere DNA was 5.7 × 10 -13 to 4.5 × 10 -6 mol/L. The detection limit (3 σ) of this method has decreased to pico-molar level.

Investigation of the feasibility of a simple method for verifying the motion of a binary multileaf collimator synchronized with the rotation of the gantry for helical tomotherapy

PubMed Central

Uematsu, Masahiro; Ito, Makiko; Hama, Yukihiro; Inomata, Takayuki; Fujii, Masahiro; Nishio, Teiji; Nakamura, Naoki; Nakagawa, Keiichi

2012-01-01

In this paper, we suggest a new method for verifying the motion of a binary multileaf collimator (MLC) in helical tomotherapy. For this we used a combination of a cylindrical scintillator and a general‐purpose camcorder. The camcorder records the light from the scintillator following photon irradiation, which we use to track the motion of the binary MLC. The purpose of this study is to demonstrate the feasibility of this method as a binary MLC quality assurance (QA) tool. First, the verification was performed using a simple binary MLC pattern with a constant leaf open time; secondly, verification using the binary MLC pattern used in a clinical setting was also performed. Sinograms of simple binary MLC patterns, in which leaves that were open were detected as “open” from the measured light, define the sensitivity which, in this case, was 1.000. On the other hand, the specificity, which gives the fraction of closed leaves detected as “closed”, was 0.919. The leaf open error identified by our method was −1.3±7.5%. The 68.6% of observed leaves were performed within ± 3% relative error. The leaf open error was expressed by the relative errors calculated on the sinogram. In the clinical binary MLC pattern, the sensitivity and specificity were 0.994 and 0.997, respectively. The measurement could be performed with −3.4±8.0% leaf open error. The 77.5% of observed leaves were performed within ± 3% relative error. With this method, we can easily verify the motion of the binary MLC, and the measurement unit developed was found to be an effective QA tool. PACS numbers: 87.56.Fc, 87.56.nk PMID:22231222

The Field Assessment Stroke Triage for Emergency Destination (FAST-ED): a Simple and Accurate Pre-Hospital Scale to Detect Large Vessel Occlusion Strokes

PubMed Central

Lima, Fabricio O.; Silva, Gisele S.; Furie, Karen L.; Frankel, Michael R.; Lev, Michael H.; Camargo, Érica CS; Haussen, Diogo C.; Singhal, Aneesh B.; Koroshetz, Walter J.; Smith, Wade S.; Nogueira, Raul G.

2016-01-01

Background and Purpose Patients with large vessel occlusion strokes (LVOS) may be better served by direct transfer to endovascular capable centers avoiding hazardous delays between primary and comprehensive stroke centers. However, accurate stroke field triage remains challenging. We aimed to develop a simple field scale to identify LVOS. Methods The FAST-ED scale was based on items of the NIHSS with higher predictive value for LVOS and tested in the STOPStroke cohort, in which patients underwent CT angiography within the first 24 hours of stroke onset. LVOS were defined by total occlusions involving the intracranial-ICA, MCA-M1, MCA-2, or basilar arteries. Patients with partial, bi-hemispheric, and/or anterior + posterior circulation occlusions were excluded. Receiver operating characteristic (ROC) curve, sensitivity, specificity, positive (PPV) and negative predictive values (NPV) of FAST-ED were compared with the NIHSS, Rapid Arterial oCclusion Evaluation (RACE) scale and Cincinnati Prehospital Stroke Severity Scale (CPSSS). Results LVO was detected in 240 of the 727 qualifying patients (33%). FAST-ED had comparable accuracy to predict LVO to the NIHSS and higher accuracy than RACE and CPSS (area under the ROC curve: FAST-ED=0.81 as reference; NIHSS=0.80, p=0.28; RACE=0.77, p=0.02; and CPSS=0.75, p=0.002). A FAST-ED ≥4 had sensitivity of 0.60, specificity 0.89, PPV 0.72, and NPV 0.82 versus RACE ≥5 of 0.55, 0.87, 0.68, 0.79 and CPSS ≥2 of 0.56, 0.85, 0.65, 0.78, respectively. Conclusions FAST-ED is a simple scale that if successfully validated in the field may be used by medical emergency professionals to identify LVOS in the pre-hospital setting enabling rapid triage of patients. PMID:27364531

Verification and Validation of Residual Stresses in Bi-Material Composite Rings

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nelson, Stacy Michelle; Hanson, Alexander Anthony; Briggs, Timothy

Process-induced residual stresses commonly occur in composite structures composed of dissimilar materials. These residual stresses form due to differences in the composite materials’ coefficients of thermal expansion and the shrinkage upon cure exhibited by polymer matrix materials. Depending upon the specific geometric details of the composite structure and the materials’ curing parameters, it is possible that these residual stresses could result in interlaminar delamination or fracture within the composite. Therefore, the consideration of potential residual stresses is important when designing composite parts and their manufacturing processes. However, the experimental determination of residual stresses in prototype parts can be time andmore » cost prohibitive. As an alternative to physical measurement, it is possible for computational tools to be used to quantify potential residual stresses in composite prototype parts. Therefore, the objectives of the presented work are to demonstrate a simplistic method for simulating residual stresses in composite parts, as well as the potential value of sensitivity and uncertainty quantification techniques during analyses for which material property parameters are unknown. Specifically, a simplified residual stress modeling approach, which accounts for coefficient of thermal expansion mismatch and polymer shrinkage, is implemented within the Sandia National Laboratories’ developed SIERRA/SolidMechanics code. Concurrent with the model development, two simple, bi-material structures composed of a carbon fiber/epoxy composite and aluminum, a flat plate and a cylinder, are fabricated and the residual stresses are quantified through the measurement of deformation. Then, in the process of validating the developed modeling approach with the experimental residual stress data, manufacturing process simulations of the two simple structures are developed and undergo a formal verification and validation process, including a mesh convergence study, sensitivity analysis, and uncertainty quantification. The simulations’ final results show adequate agreement with the experimental measurements, indicating the validity of a simple modeling approach, as well as a necessity for the inclusion of material parameter uncertainty in the final residual stress predictions.« less

Direct detection of falciparum and non-falciparum malaria DNA from a drop of blood with high sensitivity by the dried-LAMP system.

PubMed

Hayashida, Kyoko; Kajino, Kiichi; Simukoko, Humphrey; Simuunza, Martin; Ndebe, Joseph; Chota, Amos; Namangala, Boniface; Sugimoto, Chihiro

2017-01-13

Because of the low sensitivity of conventional rapid diagnostic tests (RDTs) for malaria infections, the actual prevalence of the diseases, especially those caused by non-Plasmodium falciparum (non-Pf) species, in asymptomatic populations remain less defined in countries lacking in well-equipped facilities for accurate diagnoses. Our direct blood dry LAMP system (CZC-LAMP) was applied to the diagnosis of malaria as simple, rapid and highly sensitive method as an alternative for conventional RDTs in malaria endemic areas where laboratory resources are limited. LAMP primer sets for mitochondria DNAs of Plasmodium falciparum (Pf) and human-infective species other than Pf (non-Pf; P. vivax, P. ovale, P. malariae) were designed and tested by using human blood DNA samples from 74 residents from a malaria endemic area in eastern Zambia. These malaria dry-LAMPs were optimized for field or point-of-care operations, and evaluated in the field at a malaria endemic area in Zambia with 96 human blood samples. To determine the sensitivities and specificities, results obtained by the on-site LAMP diagnosis were compared with those by the nested PCR and nucleotide sequencing of its product. The dry LAMPs showed the sensitivities of 89.7% for Pf and 85.7% for non-Pf, and the specificities of 97.2% for Pf and 100% for non-Pf, with purified blood DNA samples. The direct blood LAMP diagnostic methods, in which 1 μl of anticoagulated blood were used as the template, showed the sensitivities of 98.1% for Pf, 92.1% for non-Pf, and the specificities of 98.1% for Pf, 100% for non-Pf. The prevalences of P. falciparum, P. malariae and P. ovale in the surveyed area were 52.4, 25.3 and 10.6%, respectively, indicating high prevalence of asymptomatic carriers in endemic areas in Zambia. We have developed new field-applicable malaria diagnostic tests. The malaria CZC-LAMPs showed high sensitivity and specificity to both P. falciparum and non-P. falciparum. These malaria CZC-LAMPs provide new means for rapid, sensitive and reliable point-of-care diagnosis for low-density malaria infections, and are expected to help update current knowledge of malaria epidemiology, and can contribute to the elimination of malaria from endemic areas.

[Optimization and assessment of a reverse hybridization system for the detection of HBV drug-resistant mutations].

PubMed

Liu, Yan-chen; Huang, Ai-long; Hu, Yuan; Hu, Jie-li; Lai, Guo-qi; Zhang, Wen-lu

2011-12-01

To establish a detection method for HBV drug-resistant mutations related to lamivudine, adefovir and entecavir by optimization and assessment of reverse hybridization system. 26 degenerated probes covering 10 drug-resistant hotspots of 3 drugs were synthesized and immobilized on the same positively charged nylon membrane. PCR products labeled with digoxigenin were hybridized with corresponding probes. To improve the sensitivity and specificity, 4 reaction steps of reverse hybridization were optimized including the number of labeled digoxigenin, the energy intensity of UV cross-linking, hybridization and stringency wash conditions. To prove the feasibility, the specificity, sensitivity and accuracy of this system were assessed respectively. Sensitive and specific results are obtained by the optimization of the following 4 reaction steps: the primers labeled with 3 digoxigenin, energy intensity of UV cross-linking for 1500 x 0.1 mJ/cm², hybridization at 42 degrees C and stringency wash with 0.5 x SSC and 0.1% SDS solution at 44 degrees C for 30 min. In the assessment of system, the majority of probes have high specificity. The quantity of PCR product with a concentration of 10 ng/μl or above can be detected by this method. The concordant rate between reverse hybridization and direct sequencing is 93.9% in the clinical sample test. Though the specificity of several probes needs to be improved further, it is a simple, rapid and sensitive method which can detect HBV resistant mutations related to lamivudine, adefovir and entecavir simultaneously. Due to the short distance between 180 and 181, likewise 202 and 204, the sequence of the same probe covers two codon positions, and hybridization will be interfered by each other. To avoid such interference, the possible solution is that probes are designed by arranging and combining various forms of two near codons.

A simple but highly efficient multi-formyl phenol-amine system for fluorescence detection of peroxide explosive vapour.

PubMed

Xu, Wei; Fu, Yanyan; Gao, Yixun; Yao, Junjun; Fan, Tianchi; Zhu, Defeng; He, Qingguo; Cao, Huimin; Cheng, Jiangong

2015-07-11

A simple, highly stable, sensitive and selective fluorescent system for peroxide explosives was developed via an aromatic aldehyde oxidation reaction. The high efficiency arises from its higher HOMO level and multiple H-bonding. The sensitivity is obtained to be 0.1 ppt for H2O2 and 0.2 ppb for TATP.

A Simple Experiment for Visualizing Diffusion

ERIC Educational Resources Information Center

Helseth, L. E.

2011-01-01

We propose a simple and fascinating experiment for studying diffusion in gels using a pH-sensitive dye. By doping agar with methyl red, we obtain a gel which rapidly reacts to changes in pH by changing its absorption spectrum. The pH gradients can be followed using a digital camera, and we demonstrate here that the pH-sensitive colour changes can…

New concepts of fluorescent probes for specific detection of DNA sequences: bis-modified oligonucleotides in excimer and exciplex detection.

PubMed

Gbaj, A; Bichenkova, Ev; Walsh, L; Savage, He; Sardarian, Ar; Etchells, Ll; Gulati, A; Hawisa, S; Douglas, Kt

2009-12-01

The detection of single base mismatches in DNA is important for diagnostics, treatment of genetic diseases, and identification of single nucleotide polymorphisms. Highly sensitive, specific assays are needed to investigate genetic samples from patients. The use of a simple fluorescent nucleoside analogue in detection of DNA sequence and point mutations by hybridisation in solution is described in this study. The 5'-bispyrene and 3'-naphthalene oligonucleotide probes form an exciplex on hybridisation to target in water and the 5'-bispyrene oligonucleotide alone is an adequate probe to determine concentration of target present. It was also indicated that this system has a potential to identify mismatches and insertions. The aim of this work was to investigate experimental structures and conditions that permit strong exciplex emission for nucleic acid detectors, and show how such exciplexes can register the presence of mismatches as required in SNP analysis. This study revealed that the hybridisation of 5'-bispyrenyl fluorophore to a DNA target results in formation of a fluorescent probe with high signal intensity change and specificity for detecting a complementary target in a homogeneous system. Detection of SNP mutations using this split-probe system is a highly specific, simple, and accessible method to meet the rigorous requirements of pharmacogenomic studies. Thus, it is possible for the system to act as SNP detectors and it shows promise for future applications in genetic testing.

Clinical profiling and use of loop-mediated isothermal amplification assay for rapid detection of Mycobacterium tuberculosis from sputum.

PubMed

Poudel, A; Pandey, B D; Lekhak, B; Rijal, B; Sapkota, B R; Suzuki, Y

2009-01-01

Tuberculosis is a global health problem and the situation is worsening with newer incidences of drug resistance and HIV association. Diagnosis of tuberculosis can be done by many methods and test, culture of sputum being the ideal one. Nucleic acid amplification (NAA) assay are more time efficient one, that amplify and detect specific nucleic acid sequences allows rapid, sensitive and specific detection of M. tuberculosis in sputum samples. The present study intends to compile the clinical presentations of the pulmonary tuberculosis (PTB) patients and to evaluate the efficacy of in-house loop-mediated isothermal amplification (LAMP) in detecting Mycobacterium tuberculosis in sputum samples by comparing with microscopy and culture. Two hundred two sputum samples were collected from 202 patients at National Tuberculosis Center, Bhaktapur, Nepal. Complete clinical profiling, epidemiological data and record on BCG vaccination were noted and the samples were subjected for microscopy, culture and in-house LAMP with six primers specific for 16S RNA gene of Mycobacterium tuberculosis. Of the 176 cases of clinical profiling, productive cough was most common symptom in 147 (83.52%), followed by chest pain 136 (77.27%), fever 133 (75.56%) and haemoptysis 61 (34.66%). There was a statistically significant association between BCG vaccination and development of TB (chi(2)=5.33, P=0.02). Of 202 cases, 115 (56.93%) were chest X-ray positive, 101(50%) were direct smear-positive and 100 (49.51%) were culture positive. LAMP had a sensitivity of 97% and specificity of 94.12% while comparing with culture. In addition, its sensitivity and specificity were 91.09% and 89.11% respectively with reference to microscopy. As in our previous study, overall, the result of present study further confirms that the in-house LAMP is a simple, rapid, sensitive and specific DNA amplification technique for PTB diagnosis. Because of rapidity of microscopy and specificity of culture, in-house LAMP assay can be used as a very powerful and useful supplementary tool with complete clinical profiling of the patients for rapid diagnosis of TB in both AFB-positive and negative cases who are suspected as PTB in disease endemic country like Nepal.

A Fast, Accurate and Sensitive GC-FID Method for the Analyses of Glycols in Water and Urine

NASA Technical Reports Server (NTRS)

Kuo, C. Mike; Alverson, James T.; Gazda, Daniel B.

2017-01-01

Glycols, specifically ethylene glycol and 1,2-propanediol, are some of the major organic compounds found in the humidity condensate samples collected on the International Space Station. The current analytical method for glycols is a GC/MS method with direct sample injection. This method is simple and fast, but it is not very sensitive. Reporting limits for ethylene glycol and 1,2-propanediol are only 1 ppm. A much more sensitive GC/FID method was developed, in which glycols were derivatized with benzoyl chloride for 10 minutes before being extracted with hexane. Using 1,3-propanediol as an internal standard, the detection limits for the GC/FID method was determined to be 50 ppb and the analysis only takes 7 minutes. Data from the GC/MS and the new GC/FID methods shows excellent agreement with each other. Factors affecting the sensitivity, including sample volume, NaOH concentration and volume, volume of benzoyl chloride, reaction time and temperature, were investigated. Interferences during derivatization and possible method to reduce interferences were also investigated.

Magnetically-focusing biochip structures for high-speed active biosensing with improved selectivity.

PubMed

Yoo, Haneul; Lee, Dong Jun; Kim, Daesan; Park, Juhun; Chen, Xing; Hong, Seunghun

2018-06-29

We report a magnetically-focusing biochip structure enabling a single layered magnetic trap-and-release cycle for biosensors with an improved detection speed and selectivity. Here, magnetic beads functionalized with specific receptor molecules were utilized to trap target molecules in a solution and transport actively to and away from the sensor surfaces to enhance the detection speed and reduce the non-specific bindings, respectively. Using our method, we demonstrated the high speed detection of IL-13 antigens with the improved detection speed by more than an order of magnitude. Furthermore, the release step in our method was found to reduce the non-specific bindings and improve the selectivity and sensitivity of biosensors. This method is a simple but powerful strategy and should open up various applications such as ultra-fast biosensors for point-of-care services.

Magnetically-focusing biochip structures for high-speed active biosensing with improved selectivity

NASA Astrophysics Data System (ADS)

Yoo, Haneul; Lee, Dong Jun; Kim, Daesan; Park, Juhun; Chen, Xing; Hong, Seunghun

2018-06-01

We report a magnetically-focusing biochip structure enabling a single layered magnetic trap-and-release cycle for biosensors with an improved detection speed and selectivity. Here, magnetic beads functionalized with specific receptor molecules were utilized to trap target molecules in a solution and transport actively to and away from the sensor surfaces to enhance the detection speed and reduce the non-specific bindings, respectively. Using our method, we demonstrated the high speed detection of IL-13 antigens with the improved detection speed by more than an order of magnitude. Furthermore, the release step in our method was found to reduce the non-specific bindings and improve the selectivity and sensitivity of biosensors. This method is a simple but powerful strategy and should open up various applications such as ultra-fast biosensors for point-of-care services.

The application of sensitivity analysis to models of large scale physiological systems

NASA Technical Reports Server (NTRS)

Leonard, J. I.

1974-01-01

A survey of the literature of sensitivity analysis as it applies to biological systems is reported as well as a brief development of sensitivity theory. A simple population model and a more complex thermoregulatory model illustrate the investigatory techniques and interpretation of parameter sensitivity analysis. The role of sensitivity analysis in validating and verifying models, and in identifying relative parameter influence in estimating errors in model behavior due to uncertainty in input data is presented. This analysis is valuable to the simulationist and the experimentalist in allocating resources for data collection. A method for reducing highly complex, nonlinear models to simple linear algebraic models that could be useful for making rapid, first order calculations of system behavior is presented.

Sensitive sub-Doppler nonlinear spectroscopy for hyperfine-structure analysis using simple atomizers

NASA Astrophysics Data System (ADS)

Mickadeit, Fritz K.; Kemp, Helen; Schafer, Julia; Tong, William M.

1998-05-01

Laser wave-mixing spectroscopy is presented as a sub-Doppler method that offers not only high spectral resolution, but also excellent detection sensitivity. It offers spectral resolution suitable for hyperfine structure analysis and isotope ratio measurements. In a non-planar backward- scattering four-wave mixing optical configuration, two of the three input beams counter propagate and the Doppler broadening is minimized, and hence, spectral resolution is enhanced. Since the signal is a coherent beam, optical collection is efficient and signal detection is convenient. This simple multi-photon nonlinear laser method offers un usually sensitive detection limits that are suitable for trace-concentration isotope analysis using a few different types of simple analytical atomizers. Reliable measurement of hyperfine structures allows effective determination of isotope ratios for chemical analysis.

Predictors of conversion to dementia of probable Alzheimer type in patients with mild cognitive impairment.

PubMed

Modrego, Pedro J

2006-04-01

Mild Cognitive Impairment is a common condition defined as transitional state between normality and dementia of Alzheimer type. Clinically is characterized by subjective and objective memory loss beyond the expected for age and educational level, although a broad range of cognitive inefficiencies may appear, with preservation of daily living activities. Approximately half the patients convert to dementia within 3 years. Since no all patients convert to dementia it is essential to find reliable predictors so as to start the appropriate treatment as soon as possible. Extensive Medline-based search for articles dealing with predictors of conversion to dementia in Mild Cognitive Impairment (MCI). There is a substantial body of literature dealing with predictors of dementia in patients with MCI. These predictors range from a simple delayed recall task on Mini-Mental to sophisticated radiological techniques and CSF biomarkers. Comprehensive neuropsychological tests rarely surpass 70% sensitivity and specificity. The presence of the APOE epsilon 4 allele has been associated with increased risk of conversion but the sensitivity is quite low. CSF biochemical markers are being developed with encouraging results. beta-amyloid 42 protein is usually lower in converters than in people with stable cognitive status and tau protein is higher. The sensitivity is substantial but specificity is so far low. An epitope of tau protein (P231) looks more specific of Alzheimer's disease and therefore a promising biomarker. In the blood, high beta-amyloid protein levels indicate risk of conversion but only a few studies have been published. Hippocampal or entorhinal atrophy on MRI is one of the most used radiological markers of conversion but quantification of atrophy is not simple as it is subject to artifacts and anatomic variations. Proton Magnetic Resonance Spectroscopy (MRS) and Positron Emission Tomography (PET) are emerging as the most promising predictive tools. The highest degree of accuracy (>90%) has been achieved by means of PET plus either memory performance or APOE4 genotype. However, the samples of the published studies are mostly small, and these instruments are not widely available. There is no enough evidence to recommend specific techniques for predictions. Until an accurate marker is developed, a combined use of cognitive tests, APOE genotype, and a neuroradiological technique is probably the best option for prediction purposes depending on availability and experience.

Antibody-based assay discriminates Zika virus infection from other flaviviruses

PubMed Central

Balmaseda, Angel; Stettler, Karin; Medialdea-Carrera, Raquel; Collado, Damaris; Jin, Xia; Zambrana, José Victor; Jaconi, Stefano; Cameroni, Elisabetta; Saborio, Saira; Rovida, Francesca; Percivalle, Elena; Ijaz, Samreen; Dicks, Steve; Ushiro-Lumb, Ines; Barzon, Luisa; Siqueira, Patricia; Brown, David W. G.; Baldanti, Fausto; Tedder, Richard; Zambon, Maria; de Filippis, A. M. Bispo; Harris, Eva

2017-01-01

Zika virus (ZIKV) is a mosquito-borne flavivirus that emerged recently as a global health threat, causing a pandemic in the Americas. ZIKV infection mostly causes mild disease, but is linked to devastating congenital birth defects and Guillain-Barré syndrome in adults. The high level of cross-reactivity among flaviviruses and their cocirculation has complicated serological approaches to differentially detect ZIKV and dengue virus (DENV) infections, accentuating the urgent need for a specific and sensitive serological test. We previously generated a ZIKV nonstructural protein 1 (NS1)-specific human monoclonal antibody, which we used to develop an NS1-based competition ELISA. Well-characterized samples from RT-PCR-confirmed patients with Zika and individuals exposed to other flavivirus infections or vaccination were used in a comprehensive analysis to determine the sensitivity and specificity of the NS1 blockade-of-binding (BOB) assay, which was established in laboratories in five countries (Nicaragua, Brazil, Italy, United Kingdom, and Switzerland). Of 158 sera/plasma from RT-PCR-confirmed ZIKV infections, 145 (91.8%) yielded greater than 50% inhibition. Of 171 patients with primary or secondary DENV infections, 152 (88.9%) scored negative. When the control group was extended to patients infected by other flaviviruses, other viruses, or healthy donors (n = 540), the specificity was 95.9%. We also analyzed longitudinal samples from DENV-immune and DENV-naive ZIKV infections and found inhibition was achieved within 10 d postonset of illness and maintained over time. Thus, the Zika NS1 BOB assay is sensitive, specific, robust, simple, low-cost, and accessible, and can detect recent and past ZIKV infections for surveillance, seroprevalence studies, and intervention trials. PMID:28716913

Antibody-based assay discriminates Zika virus infection from other flaviviruses.

PubMed

Balmaseda, Angel; Stettler, Karin; Medialdea-Carrera, Raquel; Collado, Damaris; Jin, Xia; Zambrana, José Victor; Jaconi, Stefano; Cameroni, Elisabetta; Saborio, Saira; Rovida, Francesca; Percivalle, Elena; Ijaz, Samreen; Dicks, Steve; Ushiro-Lumb, Ines; Barzon, Luisa; Siqueira, Patricia; Brown, David W G; Baldanti, Fausto; Tedder, Richard; Zambon, Maria; de Filippis, A M Bispo; Harris, Eva; Corti, Davide

2017-08-01

Zika virus (ZIKV) is a mosquito-borne flavivirus that emerged recently as a global health threat, causing a pandemic in the Americas. ZIKV infection mostly causes mild disease, but is linked to devastating congenital birth defects and Guillain-Barré syndrome in adults. The high level of cross-reactivity among flaviviruses and their cocirculation has complicated serological approaches to differentially detect ZIKV and dengue virus (DENV) infections, accentuating the urgent need for a specific and sensitive serological test. We previously generated a ZIKV nonstructural protein 1 (NS1)-specific human monoclonal antibody, which we used to develop an NS1-based competition ELISA. Well-characterized samples from RT-PCR-confirmed patients with Zika and individuals exposed to other flavivirus infections or vaccination were used in a comprehensive analysis to determine the sensitivity and specificity of the NS1 blockade-of-binding (BOB) assay, which was established in laboratories in five countries (Nicaragua, Brazil, Italy, United Kingdom, and Switzerland). Of 158 sera/plasma from RT-PCR-confirmed ZIKV infections, 145 (91.8%) yielded greater than 50% inhibition. Of 171 patients with primary or secondary DENV infections, 152 (88.9%) scored negative. When the control group was extended to patients infected by other flaviviruses, other viruses, or healthy donors ( n = 540), the specificity was 95.9%. We also analyzed longitudinal samples from DENV-immune and DENV-naive ZIKV infections and found inhibition was achieved within 10 d postonset of illness and maintained over time. Thus, the Zika NS1 BOB assay is sensitive, specific, robust, simple, low-cost, and accessible, and can detect recent and past ZIKV infections for surveillance, seroprevalence studies, and intervention trials.

Preparation of immunochromatographic strips for rapid detection of early secreted protein ESAT-6 and culture filtrate protein CFP-10 from Mycobacterium tuberculosis

PubMed Central

Wu, Xiaoxin; Wang, Yeping; Weng, Tianhao; Hu, Chenyu; Wang, Frederick X.C.; Wu, Zhigang; Yu, Dongshan; Lu, Huoquan; Yao, Hangping

2017-01-01

Abstract The early secreted protein early secretory antigenic target 6(ESAT-6) and the culture filtrate protein 10 (CFP-10) are 2 antigens that are specific to Mycobacterium tuberculosis. These 2 antigens are good targets for tuberculosis (TB) detection. To rapidly diagnose TB across a variety of samples, we developed colloidal gold immunochromatographic strips (ICSs) based on ESAT-6 and CFP-10. The strips were evaluated using 233 samples, including sputum, plasma, and pleural effusion samples. The positive detection rates for ICSs for ESAT-6 and CFP-10 in sputum (culture-positive for M tuberculosis) were 100% and 91.2%, respectively. The positive detection rates for ICSs for ESAT-6 and CFP-10 in plasma were 34.1% and 29.4%, respectively. The positive detection rates for ICSs for ESAT-6 and CFP-10 in pleural effusion were 64.7% and 55.9%, respectively. Experimental analysis of culture supernatant showing that the ICS developed for ESAT-6 had a sensitivity of 100% and a specificity of 91.2%. While the ICS developed for CFP-10 had a sensitivity of 91.2% and a specificity of 88.2%. The validity of the test is limited by source of sample. The technique is sensitive and specific for samples in sputum and culture media but not for plasma or pleural effusion samples. Detection of M tuberculosis using ICSs is rapid, simple, and relatively effective; thus, ICSs are a potential screening tool for TB. PMID:29390519

Accuracy of body mass index in volunteer firefighters.

PubMed

Ode, J; Knous, J; Schlaff, R; Hemenway, J; Peterson, J; Lowry, J

2014-04-01

Obesity is prevalent among career firefighters and may contribute to heart attacks, a leading cause of on-duty fatalities. The US National Fire Protection Association estimates that 800 000 of 1.1 million firefighters are volunteers. Body mass index (BMI) is commonly used to assess obesity, but little is known about its accuracy in volunteer firefighters, in whom muscle mass may be higher, given firefighting's physical demands, reducing its accuracy in identifying obesity. To evaluate the accuracy of BMI in identifying obese volunteer firefighters. Height, weight and body composition were measured in 73 male volunteer firefighters (mean age 40±12). The proportions with BMI ≥ 25kg/m(2), ≥30kg/ m(2) and percent fat ≤ 20th percentile were determined. Using the age-specific 20th percentile for percent fat (Cooper Clinic) as the criterion for being over-fat, the accuracy of BMI was assessed using sensitivity and specificity calculations. The means ± standard deviation of BMI and percent fat were 32±6 and 25±5, respectively. The proportions with a BMI ≥ 25 and ≥30 were 90% and 60%, respectively. Fifty-one percent had a percent fat ≤ 20th percentile. The measure BMI ≥ 25 had a perfect sensitivity (1.0) and low specificity (0.19) and BMI ≥ 30 had a high sensitivity (0.89) and moderate specificity (0.69). Although BMI ≥ 30 accurately predicted being over-fat, it misclassified large and lean firefighters. Although BMI should be used cautiously, it can identify over-fat firefighters at risk of cardiovascular disease, and its measurement is cost-effective and simple.

Region of interest methylation analysis: a comparison of MSP with MS-HRM and direct BSP.

PubMed

Akika, Reem; Awada, Zainab; Mogharbil, Nahed; Zgheib, Nathalie K

2017-07-01

The aim of this study was to compare and contrast three DNA methylation methods of a specific region of interest (ROI): methylation-specific PCR (MSP), methylation-sensitive high resolution melting (MS-HRM) and direct bisulfite sequencing (BSP). The methylation of a CpG area in the promoter region of Estrogen receptor alpha (ESR1) was evaluated by these three methods with samples and standards of different methylation percentages. MSP data were neither reproducible nor sensitive, and the assay was not specific due to non-specific binding of primers. MS-HRM was highly reproducible and a step forward into categorizing the methylation status of the samples as percent ranges. Direct BSP was the most informative method regarding methylation percentage of each CpG site. Though not perfect, it was reproducible and sensitive. We recommend the use of either method depending on the research question and target amplicon, and provided that the designed primers and expected amplicons are within recommendations. If the research question targets a limited number of CpG sites and simple yes/no results are enough, MSP may be attempted. For short amplicons that are crowded with CpG sites and of single melting domain, MS-HRM may be the method of choice though it only indicates the overall methylation percentage of the entire amplicon. Although the assay is highly reproducible, being semi-quantitative makes it of lesser interest to study ROI methylation of samples with little methylation differences. Direct BSP is a step forward as it gives information about the methylation percentage at each CpG site.

Recombinant antibodies and their use in biosensors.

PubMed

Zeng, Xiangqun; Shen, Zhihong; Mernaugh, Ray

2012-04-01

Inexpensive, noninvasive immunoassays can be used to quickly detect disease in humans. Immunoassay sensitivity and specificity are decidedly dependent upon high-affinity, antigen-specific antibodies. Antibodies are produced biologically. As such, antibody quality and suitability for use in immunoassays cannot be readily determined or controlled by human intervention. However, the process through which high-quality antibodies can be obtained has been shortened and streamlined by use of genetic engineering and recombinant antibody techniques. Antibodies that traditionally take several months or more to produce when animals are used can now be developed in a few weeks as recombinant antibodies produced in bacteria, yeast, or other cell types. Typically most immunoassays use two or more antibodies or antibody fragments to detect antigens that are indicators of disease. However, a label-free biosensor, for example, a quartz-crystal microbalance (QCM) needs one antibody only. As such, the cost and time needed to design and develop an immunoassay can be substantially reduced if recombinant antibodies and biosensors are used rather than traditional antibody and assay (e.g. enzyme-linked immunosorbant assay, ELISA) methods. Unlike traditional antibodies, recombinant antibodies can be genetically engineered to self-assemble on biosensor surfaces, at high density, and correctly oriented to enhance antigen-binding activity and to increase assay sensitivity, specificity, and stability. Additionally, biosensor surface chemistry and physical and electronic properties can be modified to further increase immunoassay performance above and beyond that obtained by use of traditional methods. This review describes some of the techniques investigators have used to develop highly specific and sensitive, recombinant antibody-based biosensors for detection of antigens in simple or complex biological samples.

Preparation of immunochromatographic strips for rapid detection of early secreted protein ESAT-6 and culture filtrate protein CFP-10 from Mycobacterium tuberculosis.

PubMed

Wu, Xiaoxin; Wang, Yeping; Weng, Tianhao; Hu, Chenyu; Wang, Frederick X C; Wu, Zhigang; Yu, Dongshan; Lu, Huoquan; Yao, Hangping

2017-12-01

The early secreted protein early secretory antigenic target 6(ESAT-6) and the culture filtrate protein 10 (CFP-10) are 2 antigens that are specific to Mycobacterium tuberculosis. These 2 antigens are good targets for tuberculosis (TB) detection.To rapidly diagnose TB across a variety of samples, we developed colloidal gold immunochromatographic strips (ICSs) based on ESAT-6 and CFP-10.The strips were evaluated using 233 samples, including sputum, plasma, and pleural effusion samples.The positive detection rates for ICSs for ESAT-6 and CFP-10 in sputum (culture-positive for M tuberculosis) were 100% and 91.2%, respectively. The positive detection rates for ICSs for ESAT-6 and CFP-10 in plasma were 34.1% and 29.4%, respectively. The positive detection rates for ICSs for ESAT-6 and CFP-10 in pleural effusion were 64.7% and 55.9%, respectively. Experimental analysis of culture supernatant showing that the ICS developed for ESAT-6 had a sensitivity of 100% and a specificity of 91.2%. While the ICS developed for CFP-10 had a sensitivity of 91.2% and a specificity of 88.2%.The validity of the test is limited by source of sample. The technique is sensitive and specific for samples in sputum and culture media but not for plasma or pleural effusion samples. Detection of M tuberculosis using ICSs is rapid, simple, and relatively effective; thus, ICSs are a potential screening tool for TB. Copyright © 2017 The Authors. Published by Wolters Kluwer Health, Inc. All rights reserved.

Simple Identification of Human Taenia Species by Multiplex Loop-Mediated Isothermal Amplification in Combination with Dot Enzyme-Linked Immunosorbent Assay.

PubMed

Nkouawa, Agathe; Sako, Yasuhito; Okamoto, Munehiro; Ito, Akira

2016-06-01

For differential detection of Taenia solium, Taenia saginata, and Taenia asiatica, loop-mediated isothermal amplification (LAMP) assay targeting the cytochrome c oxidase subunit 1 gene has been recently developed and shown to be sensitive, specific, and effective. However, to achieve differential identification, one specimen requires three reaction mixtures containing a primer set of each Taenia species separately, which is complex and time consuming and increases the risk of cross-contamination. In this study, we developed a simple differential identification of human Taenia species using multiplex LAMP (mLAMP) in combination with dot enzyme-linked immunosorbent assay (dot-ELISA). Forward inner primers of T. solium, T. saginata, and T. asiatica labeled with fluorescein isothiocyanate (FITC), digoxigenin (DIG), and tetramethylrhodamine (TAMRA), respectively, and biotin-labeled backward inner primers were used in mLAMP. The mLAMP assay succeeded in specific amplification of each respective target gene in a single tube. Furthermore, the mLAMP product from each species was easily distinguished by dot-ELISA with an antibody specific for FITC, DIG, or TAMRA. The mLAMP assay in combination with dot-ELISA will make identification of human Taenia species simpler, easier, and more practical. © The American Society of Tropical Medicine and Hygiene.

Production and Evaluation of a Purified Adenovirus Group-Specific (Hexon) Antigen for Use in the Diagnostic Complement Fixation Test

PubMed Central

Dowdle, W. R.; Lambriex, M.; Hierholzer, J. C.

1971-01-01

A simple procedure for the production of large volumes of purified adenovirus group-specific complement-fixing (CF) (hexon) antigen by selective adsorption to and elution from CaHPO4 is described. Results of immunodiffusion tests, electrophoresis, electron microscopy, and tests for hemagglutination and infectivity indicate that the purified antigen consisted of a single virus component (hexon). The purified product contained little host materials. Unlike the crude virus harvest usually employed for serodiagnostic CF tests, the purified antigen demonstrated no anticomplementary activity and did not develop such activity during storage. The purified antigen was equal to or slightly more sensitive than crude virus harvests for serodiagnosis of adenovirus infections. Images PMID:4325021

Machine learning plus optical flow: a simple and sensitive method to detect cardioactive drugs

NASA Astrophysics Data System (ADS)

Lee, Eugene K.; Kurokawa, Yosuke K.; Tu, Robin; George, Steven C.; Khine, Michelle

2015-07-01

Current preclinical screening methods do not adequately detect cardiotoxicity. Using human induced pluripotent stem cell-derived cardiomyocytes (iPS-CMs), more physiologically relevant preclinical or patient-specific screening to detect potential cardiotoxic effects of drug candidates may be possible. However, one of the persistent challenges for developing a high-throughput drug screening platform using iPS-CMs is the need to develop a simple and reliable method to measure key electrophysiological and contractile parameters. To address this need, we have developed a platform that combines machine learning paired with brightfield optical flow as a simple and robust tool that can automate the detection of cardiomyocyte drug effects. Using three cardioactive drugs of different mechanisms, including those with primarily electrophysiological effects, we demonstrate the general applicability of this screening method to detect subtle changes in cardiomyocyte contraction. Requiring only brightfield images of cardiomyocyte contractions, we detect changes in cardiomyocyte contraction comparable to - and even superior to - fluorescence readouts. This automated method serves as a widely applicable screening tool to characterize the effects of drugs on cardiomyocyte function.

Determination of Urine Albumin by New Simple High-Performance Liquid Chromatography Method.

PubMed

Klapkova, Eva; Fortova, Magdalena; Prusa, Richard; Moravcova, Libuse; Kotaska, Karel

2016-11-01

A simple high-performance liquid chromatography (HPLC) method was developed for the determination of albumin in patients' urine samples without coeluting proteins and was compared with the immunoturbidimetric determination of albumin. Urine albumin is important biomarker in diabetic patients, but part of it is immuno-nonreactive. Albumin was determined by high-performance liquid chromatography (HPLC), UV detection at 280 nm, Zorbax 300SB-C3 column. Immunoturbidimetric analysis was performed using commercial kit on automatic biochemistry analyzer COBAS INTEGRA ® 400, Roche Diagnostics GmbH, Manheim, Germany. The HLPC method was fully validated. No significant interference with other proteins (transferrin, α-1-acid glycoprotein, α-1-antichymotrypsin, antitrypsin, hemopexin) was found. The results from 301 urine samples were compared with immunochemical determination. We found a statistically significant difference between these methods (P = 0.0001, Mann-Whitney test). New simple HPLC method was developed for the determination of urine albumin without coeluting proteins. Our data indicate that the HPLC method is highly specific and more sensitive than immunoturbidimetry. © 2016 Wiley Periodicals, Inc.

Use of refractometry and colorimetry as field methods to rapidly assess antimalarial drug quality.

PubMed

Green, Michael D; Nettey, Henry; Villalva Rojas, Ofelia; Pamanivong, Chansapha; Khounsaknalath, Lamphet; Grande Ortiz, Miguel; Newton, Paul N; Fernández, Facundo M; Vongsack, Latsamy; Manolin, Ot

2007-01-04

The proliferation of counterfeit and poor-quality drugs is a major public health problem; especially in developing countries lacking adequate resources to effectively monitor their prevalence. Simple and affordable field methods provide a practical means of rapidly monitoring drug quality in circumstances where more advanced techniques are not available. Therefore, we have evaluated refractometry, colorimetry and a technique combining both processes as simple and accurate field assays to rapidly test the quality of the commonly available antimalarial drugs; artesunate, chloroquine, quinine, and sulfadoxine. Method bias, sensitivity, specificity and accuracy relative to high-performance liquid chromatographic (HPLC) analysis of drugs collected in the Lao PDR were assessed for each technique. The HPLC method for each drug was evaluated in terms of assay variability and accuracy. The accuracy of the combined method ranged from 0.96 to 1.00 for artesunate tablets, chloroquine injectables, quinine capsules, and sulfadoxine tablets while the accuracy was 0.78 for enterically coated chloroquine tablets. These techniques provide a generally accurate, yet simple and affordable means to assess drug quality in resource-poor settings.

A highly rapid and simple competitive enzyme-linked immunosorbent assay for monitoring paralytic shellfish poisoning toxins in shellfish.

PubMed

Kawatsu, Kentaro; Kanki, Masashi; Harada, Tetsuya; Kumeda, Yuko

2014-11-01

Using a streptavidin-coated well plate, a biotin-labelled anti-gonyautoxin 2/3 monoclonal antibody GT-13A, and a decarbamoyl saxitoxin-peroxidase conjugate, a direct competitive enzyme-linked immunosorbent assay (PSP-ELISA) was developed for monitoring paralytic shellfish poisoning (PSP) toxins in shellfish. This assay is simple to perform and can be completed in approximately 20 min. The PSP-ELISA was compared to the mouse bioassay (MBA) for the detection of PSP toxins in shellfish samples (n=83) collected from the coast of Osaka Prefecture, Japan. When positive and negative results were indicated based on the regulatory limit for PSP toxins (4 mouse unit(MU)/g of shellfish meat), the PSP-ELISA results showed a sensitivity of 100% (25 of 25) and a specificity of 89.7% (52 of 58 samples) compared to the MBA results. These results suggest that the PSP-ELISA could be used as a rapid and simple screening method prior to the MBA. Copyright © 2014 Elsevier Ltd. All rights reserved.

A sensitive, rapid, and simple DR-EcoScreen bioassay for the determination of PCDD/Fs and dioxin-like PCBs in environmental and food samples.

PubMed

Kojima, Hiroyuki; Takeuchi, Shinji; Iida, Mitsuru; Nakayama, Shoji F; Shiozaki, Takuya

2018-03-01

In developing countries in Asia, such as China, Vietnam, and Thailand, there is a strong need for the development of relatively rapid and low-cost bioassays for the determination of polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), and dioxin-like polychlorinated biphenyls (DL-PCBs) in environmental and food samples. These compounds are known to induce a variety of toxic and biological effects through their ligand-specific binding of the aryl hydrocarbon receptor (AhR). Indeed, several AhR-mediated reporter gene assays are widely used as prescreening tools for high-resolution gas chromatography/high-resolution mass spectrometry (HRGC-HRMS) analysis, which individually measures 17 PCDD/Fs and 12 DL-PCBs. In 2008, we have developed a new sensitive and rapid reporter gene assay using a genetically engineered stable cell line, designated DR-EcoScreen cells. The DR-EcoScreen assay using these cells has a number of great advantages of its sensitivity to 2,3,7,8-tetrachlorodibenzo-p-dioxin and its simple procedure, which shows little variance in the data (within CV 10 %) compared to other reporter gene assays. In this review, we summarize the application of the DR-EcoScreen assay to the determination of PCDD/Fs and DL-PCBs in ambient air samples, in fish and shellfish samples, and in flue gas samples from incinerators and provide potential usefulness of this bioassay for the determination of PCDD/Fs and DL-PCBs in various matrices.

Ultrasensitive signal-on DNA biosensor based on nicking endonuclease assisted electrochemistry signal amplification.

PubMed

Liu, Zhongyuan; Zhang, Wei; Zhu, Shuyun; Zhang, Ling; Hu, Lianzhe; Parveen, Saima; Xu, Guobao

2011-11-15

Combining the advantages of signal-on strategy and nicking endonuclease assisted electrochemistry signal amplification (NEAESA), a new sensitive and signal-on electrochemical DNA biosensor for the sequence specific DNA detection based on NEAESA has been developed for the first time. A Hairpin-shape probe (HP), containing the target DNA recognition sequence, is thiol-modified at 5' end and immobilized on gold electrode via Au-S bonding. Subsequently, the HP modified electrode is hybridized with target DNA to form a duplex. Then the nicking endonuclease is added and nicks the HP strand in the duplex. After nicking, 3'-ferrocene (Fc)-labeled part complementary probe (Fc-PCP) is introduced on the electrode surface by hybridizing with the thiol-modified HP fragment, which results in the generation of electrochemical signal. Hence, the DNA biosensor is constructed successfully. The present DNA biosensor shows a wide linear range of 5.0×10(-13)-5.0×10(-8)M for detecting target DNA, with a low detection limit of 0.167pM. The proposed strategy does not require any amplifying labels (enzymes, DNAzymes, nanoparticles, etc.) for biorecognition events, which avoids false-positive results to occur frequently. Moreover, the strategy has the benefits of simple preparation, convenient operation, good selectivity, and high sensitivity. With the advantages mentioned above, this simple and sensitive strategy has the potential to be integrated in portable, low cost and simplified devices for diagnostic applications. Copyright © 2011 Elsevier B.V. All rights reserved.

Comparison between culture and a multiplex quantitative real-time polymerase chain reaction assay detecting Ureaplasma urealyticum and U. parvum.

PubMed

Frølund, Maria; Björnelius, Eva; Lidbrink, Peter; Ahrens, Peter; Jensen, Jørgen Skov

2014-01-01

A novel multiplex quantitative real-time polymerase chain reaction (qPCR) for simultaneous detection of U. urealyticum and U. parvum was developed and compared with quantitative culture in Shepard's 10 C medium for ureaplasmas in urethral swabs from 129 men and 66 women, and cervical swabs from 61 women. Using culture as the gold standard, the sensitivity of the qPCR was 96% and 95% for female urethral and cervical swabs, respectively. In male urethral swabs the sensitivity was 89%. The corresponding specificities were 100%, 87% and 99%. The qPCR showed a linear increasing DNA copy number with increasing colour-changing units. Although slightly less sensitive than culture, this multiplex qPCR assay detecting U. urealyticum and U. parvum constitutes a simple and fast alternative to the traditional methods for identification of ureaplasmas and allows simultaneous species differentiation and quantitation in clinical samples. Furthermore, specimens overgrown by other bacteria using the culture method can be evaluated in the qPCR.

Age specific fast breathing in under-five diarrheal children in an urban hospital: Acidosis or pneumonia?

PubMed

Nuzhat, Sharika; Ahmed, Tahmeed; Kawser, Chowdhury Ali; Khan, Azharul Islam; Islam, S M Rafiqul; Shahrin, Lubaba; Shahunja, K M; Shahid, Abu S M S B; Al Imran, Abdullah; Chisti, Mohammod Jobayer

2017-01-01

Children with diarrhea often present with fast breathing due to metabolic acidosis from dehydration. On the other hand, age specific fast breathing is the cornerstone for the diagnosis of pneumonia following classification of pneumonia recommended by the World Health Organization (WHO). Correction of metabolic acidosis by rehydrating the diarrheal children requires time, which delays early initiation of appropriate antimicrobials for pneumonia and thereby increases the risk of deaths. We need to further investigate the simple clinical features other than fast breathing which might help us in earliest diagnosis of pneumonia in children with diarrhea Thus, the objective of our study was to identify other contributing clinical features that may independently help for early diagnosis of pneumonia in diarrheal children who present with age specific fast breathing. This was an unmatched case-control study. Diarrheal children aged 0-59 months, admitted to Dhaka Hospital of the International Centre for Diarrheal Disease Research, Bangladesh (icddr,b) during January 2014 to December 2014 having age specific fast breathing (<2 month ≥60 breath/min, 2-11 months ≥50 breaths/min, >11-59 months ≥40 breaths/min) were studied. The study children with clinical and radiological pneumonia constituted the cases (n = 276) and those without pneumonia constituted the controls (n = 446). Comparison of clinical features and outcomes between the cases and the controls was made. The distribution of acidosis among the cases and the controls was comparable (35% vs. 41%, p = 0.12). The cases had proportionately higher deaths compared to the controls, however, the difference was not statistically significant (3% vs. 1%; p = 0.23). In logistic regression analysis after adjusting for potential confounders, the cases were independently associated with cough (OR = 62.19, 95% CI = 27.79-139.19; p<0.01) and chest wall indrawing (OR = 31.05, 95%CI = 13.43-71.82; p<0.01) and less often had severe acute malnutrition (OR = 0.33, 95%CI = 0.13-0.79; p<0.01). The sensitivity and specificity of cough were 83% (78-87%) and 93% (91-96%). The sensitivity and specificity for lower chest wall indrawing were 65% (59-71%) and 95% (93-97%). However, the sensitivity and specificity of cough and lower chest wall indrawing combined were 94% (89-97%) and 99% (97-100%). Thus, diarrheal children having fast breathing who present with cough and/or lower chest wall indrawing, irrespective of presence or absence of metabolic acidosis, are more likely to have radiological pneumonia. The results underscore the importance of early identification of these simple clinical features that may help to minimize potential delay due to rehydration in initiating prompt treatment of pneumonia in order to reduce fatal consequences in such children.

Screening protocol for dysphagia in adults: comparison with videofluoroscopic findings.

PubMed

Sassi, Fernanda C; Medeiros, Gisele C; Zilberstein, Bruno; Jayanthi, Shri Krishna; de Andrade, Claudia R F

2017-12-01

To compare the videofluoroscopic findings of patients with suspected oropharyngeal dysphagia with the results of a clinical screening protocol. A retrospective observational cohort study was conducted on all consecutive patients with suspected oropharyngeal dysphagia between March 2015 and February 2016 who were assigned to receive a videofluoroscopic assessment of swallowing. All patients were first submitted to videofluoroscopy and then to the clinical assessment of swallowing. The clinical assessment was performed within the first 24 hours after videofluoroscopy. The videofluoroscopy results were analyzed regarding penetration/aspiration using an 8-point multidimensional perceptual scale. The accuracy of the clinical protocol was analyzed using the sensitivity, specificity, likelihood ratios and predictive values. The selected sample consisted of 50 patients. The clinical protocol presented a sensitivity of 50% and specificity of 95%, with an accuracy of 88%. "Cough" and "wet-hoarse" vocal quality after/during swallowing were clinical indicators that appeared to correctly identify the presence of penetration/aspiration risk. The clinical protocol used in the present study is a simple, rapid and reliable clinical assessment. Despite the absence of a completely satisfactory result, especially in terms of the sensitivity and positive predictive values, we suggest that lower rates of pneumonia can be achieved using a formal dysphagia screening method.

Development of mRNA-based body fluid identification using reverse transcription loop-mediated isothermal amplification.

PubMed

Satoh, Tetsuya; Kouroki, Seiya; Ogawa, Keita; Tanaka, Yorika; Matsumura, Kazutoshi; Iwase, Susumu

2018-04-25

Identifying body fluids from forensic samples can provide valuable evidence for criminal investigations. Messenger RNA (mRNA)-based body fluid identification was recently developed, and highly sensitive parallel identification using reverse transcription polymerase chain reaction (RT-PCR) has been described. In this study, we developed reverse transcription loop-mediated isothermal amplification (RT-LAMP) as a simple, rapid assay for identifying three common forensic body fluids, namely blood, semen, and saliva, and evaluated its specificity and sensitivity. Hemoglobin beta (HBB), transglutaminase 4 (TGM4), and statherin (STATH) were selected as marker genes for blood, semen, and saliva, respectively. RT-LAMP could be performed in a single step including both reverse transcription and DNA amplification under an isothermal condition within 60 min, and detection could be conveniently performed via visual fluorescence. Marker-specific amplification was performed in each assay, and no cross-reaction was observed among five representative forensically relevant body fluids. The detection limits of the assays were 0.3 nL, 30 nL, and 0.3 μL for blood, semen, and saliva, respectively, and their sensitivities were comparable with those of RT-PCR. Furthermore, RT-LAMP assays were applicable to forensic casework samples. It is considered that RT-LAMP is useful for body fluid identification.

A new portable sulfide monitor with a zinc-oxide semiconductor sensor for daily use and field study.

PubMed

Tanda, Naoko; Washio, Jumpei; Ikawa, Kyoko; Suzuki, Kengo; Koseki, Takeyoshi; Iwakura, Masaki

2007-07-01

For measuring oral malodor in daily clinical practice and in field study, we developed and evaluated a highly sensitive portable monitor system. We examined sensitivity and specificity of the sensor for volatile sulfur compounds (VSC) and obstructive gases, such as ethanol, acetone, and acetaldehyde. Each mouth air provided by 46 people was measured by this monitor, gas chromatography (GC), and olfactory panel and compared with each other. Based on the result, we used the monitor for mass health examination of a rural town with standardized measuring. The sensor detected hydrogen sulfide, methyl mercaptan, and dimethyl sulfide with 10-1000 times higher sensitivity than the other gases. The monitor's specificity was significantly improved by a VSC-selective filter. There were significant correlations between VSC concentration by the sulfide monitor and by GC, and by organoleptic score. Thirty-six percent of 969 examinees had oral malodor in a rural town. Seventy-eight percent of 969 examinees were motivated to take care of their oral condition by oral malodor measuring with the monitor. The portable sulfide monitor was useful to promote oral health care not only in clinics, but also in field study. The simple and quick operation system and the standardized measuring make it one of parameters of oral condition.

Sensitive Detection of Xanthomonas oryzae Pathovars oryzae and oryzicola by Loop-Mediated Isothermal Amplification

PubMed Central

Lang, Jillian M.; Langlois, Paul; Nguyen, Marian Hanna R.; Triplett, Lindsay R.; Purdie, Laura; Holton, Timothy A.; Djikeng, Appolinaire; Vera Cruz, Casiana M.; Verdier, Valérie

2014-01-01

Molecular diagnostics for crop diseases can enhance food security by enabling the rapid identification of threatening pathogens and providing critical information for the deployment of disease management strategies. Loop-mediated isothermal amplification (LAMP) is a PCR-based tool that allows the rapid, highly specific amplification of target DNA sequences at a single temperature and is thus ideal for field-level diagnosis of plant diseases. We developed primers highly specific for two globally important rice pathogens, Xanthomonas oryzae pv. oryzae, the causal agent of bacterial blight (BB) disease, and X. oryzae pv. oryzicola, the causal agent of bacterial leaf streak disease (BLS), for use in reliable, sensitive LAMP assays. In addition to pathovar distinction, two assays that differentiate X. oryzae pv. oryzae by African or Asian lineage were developed. Using these LAMP primer sets, the presence of each pathogen was detected from DNA and bacterial cells, as well as leaf and seed samples. Thresholds of detection for all assays were consistently 104 to 105 CFU ml−1, while genomic DNA thresholds were between 1 pg and 10 fg. Use of the unique sequences combined with the LAMP assay provides a sensitive, accurate, rapid, simple, and inexpensive protocol to detect both BB and BLS pathogens. PMID:24837384

A hydrogel biosensor for high selective and sensitive detection of amyloid-beta oligomers.

PubMed

Sun, Liping; Zhong, Yong; Gui, Jie; Wang, Xianwu; Zhuang, Xiaorong; Weng, Jian

2018-01-01

Alzheimer's disease (AD) is a neurodegenerative disorder characterized by progressive cognitive and memory impairment. It is the most common neurological disease that causes dementia. Soluble amyloid-beta oligomers (AβO) in blood or cerebrospinal fluid (CSF) are the pathogenic biomarker correlated with AD. A simple electrochemical biosensor using graphene oxide/gold nanoparticles (GNPs) hydrogel electrode was developed in this study. Thiolated cellular prion protein (PrP C ) peptide probe was immobilized on GNPs of the hydrogel electrode to construct an AβO biosensor. Electrochemical impedance spectroscopy was utilized for AβO analysis. The specific binding between AβO and PrP C probes on the hydrogel electrode resulted in an increase in the electron-transfer resistance. The biosensor showed high specificity and sensitivity for AβO detection. It could selectively differentiate AβO from amyloid-beta (Aβ) monomers or fibrils. Meanwhile, it was highly sensitive to detect as low as 0.1 pM AβO in artificial CSF or blood plasma. The linear range for AβO detection is from 0.1 pM to 10 nM. This biosensor could be used as a cost-effective tool for early diagnosis of AD due to its high electrochemical performance and bionic structure.

The relationship between ischaemia-modified albumin and good coronary collateral circulation.

PubMed

Gök, Murat; Kundi, Harun; Kızıltunç, Emrullah; Topcuoglu, Canan; Ornek, Ender

2018-01-01

It is important to determine the grade of the coronary collateral circulation (CCC) in patients with stable coronary artery disease. In this study, we aimed to investigate the relationship between the ischaemia-modified albumin (IMA) level and good CCC. A total of 95 patients with coronary angiography and at least one epicardial coronary artery obstruction were included in the study. The Rentrop classification was used with CCC grading, where 0 and 1 were defined as poor collateral, and 2 and 3 were defined as good collateral. The IMA level of the patients was measured using an enzyme-linked immunosorbent assay (ELISA). The receiver-operating characteristic curve was used to show the sensitivity and specificity of IMA levels and the optimal cut-off value for predicting good CCC. The multiple logistic regression analysis revealed that the IMA level in the good CCC group was higher (p < 0.045). Conversely, the high-sensitivity C-reactive protein level was lower in the good CCC group (p < 0.023). We found an IMA cut-off value (4.7 ng/mL) that indicated good CCC level, and this shows good CCC with 70.2% sensitivity and 60.3% specificity. The IMA level could serve as a simple and useful predictor of well-developed CCC.

A simple weighted scoring system to guide surgical decision-making in patients with parapneumonic pleural effusion.

PubMed

Chang, Che-Chia; Chen, Tzu-Ping; Yeh, Chi-Hsiao; Huang, Pin-Fu; Wang, Yao-Chang; Yin, Shun-Ying

2016-11-01

The selection of ideal candidates for surgical intervention among patients with parapneumonic pleural effusion remains challenging. In this retrospective study, we sought to identify the main predictors of surgical treatment and devise a simple scoring system to guide surgical decision-making. Between 2005 and 2014, we identified 276 patients with parapneumonic pleural effusion. Patients in the training set (n=201) were divided into two groups according to their treatment modality (non-surgery vs. surgery). Using multivariable logistic regression analysis, we devised a scoring system to guide surgical decision-making. The score was subsequently validated in an independent set of 75 patients. A white blood cell count >13,500/µL, pleuritic pain, loculations, and split pleura sign were identified as independent predictors of surgical treatment. A weighted score based on these factors was devised, as follows: white blood cell count >13,500/µL (one point), pleuritic pain (one point), loculations (two points), and split pleura sign (three points). A score >4 was associated with a surgical approach with a sensitivity of 93.4%, a specificity of 82.4%, and an area under curve (AUC) of 0.879 (95% confidence interval: 0.828-0.930). In the validation set, a sensitivity of 94.3% and a specificity of 79.6% were found (AUC=0.869). The proposed scoring system reliably identifies patients with parapneumonic pleural effusion who are candidates for surgery. Pending independent external validation, our score may inform the appropriate use of surgical interventions in this clinical setting.

Spectral imaging of chemical compounds using multivariate optically enhanced filters integrated with InGaAs VGA cameras

NASA Astrophysics Data System (ADS)

Priore, Ryan J.; Jacksen, Niels

2016-05-01

Infrared hyperspectral imagers (HSI) have been fielded for the detection of hazardous chemical and biological compounds, tag detection (friend versus foe detection) and other defense critical sensing missions over the last two decades. Low Size/Weight/Power/Cost (SWaPc) methods of identification of chemical compounds spectroscopy has been a long term goal for hand held applications. We describe a new HSI concept for low cost / high performance InGaAs SWIR camera chemical identification for military, security, industrial and commercial end user applications. Multivariate Optical Elements (MOEs) are thin-film devices that encode a broadband, spectroscopic pattern allowing a simple broadband detector to generate a highly sensitive and specific detection for a target analyte. MOEs can be matched 1:1 to a discrete analyte or class prediction. Additionally, MOE filter sets are capable of sensing an orthogonal projection of the original sparse spectroscopic space enabling a small set of MOEs to discriminate a multitude of target analytes. This paper identifies algorithms and broadband optical filter designs that have been demonstrated to identify chemical compounds using high performance InGaAs VGA detectors. It shows how some of the initial models have been reduced to simple spectral designs and tested to produce positive identification of such chemicals. We also are developing pixilated MOE compressed detection sensors for the detection of a multitude of chemical targets in challenging backgrounds/environments for both commercial and defense/security applications. This MOE based, real-time HSI sensor will exhibit superior sensitivity and specificity as compared to currently fielded HSI systems.

Magnetic bead-quantum dot assay for detection of a biomarker for traumatic brain injury

NASA Astrophysics Data System (ADS)

Kim, Chloe; Searson, Peter C.

2015-10-01

Current diagnostic methods for traumatic brain injury (TBI), which accounts for 15% of all emergency room visits, are limited to neuroimaging modalities. The challenges of accurate diagnosis and monitoring of TBI have created the need for a simple and sensitive blood test to detect brain-specific biomarkers. Here we report on an assay for detection of S100B, a putative biomarker for TBI, using antibody-conjugated magnetic beads for capture of the protein, and antibody-conjugated quantum dots for optical detection. From Western Blot, we show efficient antigen capture and concentration by the magnetic beads. Using magnetic bead capture and quantum dot detection in serum samples, we show a wide detection range and detection limit below the clinical cut-off level.Current diagnostic methods for traumatic brain injury (TBI), which accounts for 15% of all emergency room visits, are limited to neuroimaging modalities. The challenges of accurate diagnosis and monitoring of TBI have created the need for a simple and sensitive blood test to detect brain-specific biomarkers. Here we report on an assay for detection of S100B, a putative biomarker for TBI, using antibody-conjugated magnetic beads for capture of the protein, and antibody-conjugated quantum dots for optical detection. From Western Blot, we show efficient antigen capture and concentration by the magnetic beads. Using magnetic bead capture and quantum dot detection in serum samples, we show a wide detection range and detection limit below the clinical cut-off level. Electronic supplementary information (ESI) available. See DOI: 10.1039/c5nr05608j

A Simple Ensemble Simulation Technique for Assessment of Future Variations in Specific High-Impact Weather Events

NASA Astrophysics Data System (ADS)

Taniguchi, Kenji

2018-04-01

To investigate future variations in high-impact weather events, numerous samples are required. For the detailed assessment in a specific region, a high spatial resolution is also required. A simple ensemble simulation technique is proposed in this paper. In the proposed technique, new ensemble members were generated from one basic state vector and two perturbation vectors, which were obtained by lagged average forecasting simulations. Sensitivity experiments with different numbers of ensemble members, different simulation lengths, and different perturbation magnitudes were performed. Experimental application to a global warming study was also implemented for a typhoon event. Ensemble-mean results and ensemble spreads of total precipitation, atmospheric conditions showed similar characteristics across the sensitivity experiments. The frequencies of the maximum total and hourly precipitation also showed similar distributions. These results indicate the robustness of the proposed technique. On the other hand, considerable ensemble spread was found in each ensemble experiment. In addition, the results of the application to a global warming study showed possible variations in the future. These results indicate that the proposed technique is useful for investigating various meteorological phenomena and the impacts of global warming. The results of the ensemble simulations also enable the stochastic evaluation of differences in high-impact weather events. In addition, the impacts of a spectral nudging technique were also examined. The tracks of a typhoon were quite different between cases with and without spectral nudging; however, the ranges of the tracks among ensemble members were comparable. It indicates that spectral nudging does not necessarily suppress ensemble spread.

Evaluation of detection methods for Campylobacter infections among under-fives in Mwanza City, Tanzania

PubMed Central

Mushi, Martha Fidelis; Paterno, Laurent; Tappe, Dennis; Deogratius, Anna Pendo; Seni, Jeremiah; Moremi, Nyambura; Mirambo, Mariam Mwijuma; Mshana, Stephen Eliatosha

2014-01-01

Introduction Campylobacter species are recognized as a major cause of acute gastroenteritis in humans throughout the world. The diagnosis is mainly based on stool culture. This study was done to evaluate the effectiveness of staining methods (Gram stain using 0.3% carbol fuchsin as counter stain and 1% carbol fuchsin direct stain) versus culture as the gold standard. Methods A total of 300 children attending Bugando Medical Centre (BMC) and the Sekou Toure regional hospital with acute watery diarrhea were enrolled. Two sets of slides were prepared stained with 1% carbol fuchsin for 30 seconds first set, and the second set stained with Gram's stain using 0.3% carbol fuchsin as counter stain for five minutes. Concurrently, stool samples were inoculated on Preston Agar selective. Results Of 300 stool specimens, 14(4.7%) showed positive culture after 48 hours of incubation and 28 (9.3%) shows typical morphology of Campylobacter species by both Gram stain and direct stain. The sensitivity of the Gram stain using 0.3% carbol fuchsin as counter stain and 1% carbol fuchsin simple stain versus culture as gold standard was 64.3%, with a specificity of 93.4%. The positive predictive value and negative predictive value were 32.1% and 98.2% respectively. Conclusion The detection of Campylobacter by 1% carbol fuchsin is simple, inexpensive, and fast, with both a high sensitivity and specificity. Laboratories in settings with high prevalence of campylobacteriosis and/or limited resources can employ 1% carbol fuchsin direct stain in detecting campylobacter infections. PMID:25995788

Development and Evaluation of a Novel Loop-Mediated Isothermal Amplification Method for Rapid Detection of Severe Acute Respiratory Syndrome Coronavirus

PubMed Central

Thai, Hong Thi Cam; Le, Mai Quynh; Vuong, Cuong Duc; Parida, Manmohan; Minekawa, Harumi; Notomi, Tsugunori; Hasebe, Futoshi; Morita, Kouichi

2004-01-01

The development and evaluation of a one-step single-tube accelerated real-time quantitative reverse transcription (RT) loop-mediated isothermal amplification (LAMP) assay is reported for rapid detection of the severe acute respiratory syndrome coronavirus (SARS-CoV) replicase gene. A total of 49 samples (15 throat washes, 13 throat swabs, and 21 combined throat and nasal swabs) collected from patients admitted to the Hanoi-French and Ninhbinh hospitals in Vietnam during the SARS epidemic were evaluated and compared to conventional RT-PCR. The RT-LAMP assay demonstrated 100-fold-greater sensitivity, with a detection limit of 0.01 PFU. The sensitivity and specificity of RT-LAMP assay for detecting viral RNA in clinical specimens with regard to RT-PCR were 100 and 87%, respectively. The specificity of the RT-LAMP assay was further validated by restriction analysis as well as nucleotide sequencing of the amplified product. The concentration of virus in most of the clinical samples was 0.1 PFU (0.1 to 102 PFU), as determined from the standard curve of SARS RT-LAMP and based on the time of positivity. The assay procedure is quite simple, wherein the amplification is carried out in a single tube under isothermal conditions at 63°C, and the result can be obtained in less than 1 h (as early as 11 min). Thus, the RT-LAMP assay reported here has the advantages of rapid amplification, simple operation, and easy detection and will be useful for rapid and reliable clinical diagnosis of SARS-CoV in developing countries. PMID:15131154

Diagnostic accuracy and applicability of a PCR system for the detection of Schistosoma mansoni DNA in human urine samples from an endemic area.

PubMed

Enk, Martin Johannes; Oliveira e Silva, Guilherme; Rodrigues, Nilton Barnabé

2012-01-01

Schistosomiasis caused by Schistosoma mansoni, one of the most neglected human parasitoses in Latin America and Africa, is routinely confirmed by microscopic visualization of eggs in stool. The main limitation of this diagnostic approach is its lack of sensitivity in detecting individual low worm burdens and consequently data on infection rates in low transmission settings are little reliable. According to the scientific literature, PCR assays are characterized by high sensitivity and specificity in detecting parasite DNA in biological samples. A simple and cost effective extraction method for DNA of Schistosoma mansoni from urine samples in combination with a conventional PCR assay was developed and applied in an endemic area. This urine based PCR system was tested for diagnostic accuracy among a population of a small village in an endemic area, comparing it to a reference test composed of three different parasitological techniques. The diagnostic parameters revealed a sensitivity of 100%, a specificity of 91.20%, positive and negative predictive values of 86.25% and 100%, respectively, and a test accuracy of 94.33%. Further statistical analysis showed a k index of 0.8806, indicating an excellent agreement between the reference test and the PCR system. Data obtained from the mouse model indicate the infection can be detected one week after cercariae penetration, opening a new perspective for early detection and patient management during this stage of the disease. The data indicate that this innovative PCR system provides a simple to handle and robust diagnostic tool for the detection of S. mansoni DNA from urine samples and a promising approach to overcome the diagnostic obstacles in low transmission settings. Furthermore the principals of this molecular technique, based on the examination of human urine samples may be useful for the diagnosis of other neglected tropical diseases that can be detected by trans-renal DNA.

An adjuvant free mouse model of oral allergenic sensitization to rice seeds protein

PubMed Central

2011-01-01

Background Rice is commonly known as a staple crop consumed worldwide, though with several rice proteins being reported for allergic properties in clinical studies. Thus, there is a growing need for the development of an animal model to better understand the allergenicity of rice proteins and the immunological and pathophysiological mechanisms underlying the development of food allergy. Methods Groups of BALB/c mice were sensitized daily with freshly homogenized rice flour (30 mg or 80 mg) without adjuvant by intragastric gavage. In addition, the mice were challenged with extracted rice flour proteins at several time points intragastrically. Hypersensitivity symptoms in mice were evaluated according to a scoring system. Vascular leakage, ELISA of rice protein-specific IgE, histopathology of small intestine, and passive cutaneous anaphylaxis were conducted on challenged mice. Results An adjuvant free mouse model of rice allergy was established with sensitized mice showing increased scratching behaviors and increased vascular permeability. Rice protein-specific IgE was detected after eighteen days of sensitization and from the fifth challenge onwards. Inflammatory damage to the epithelium in the small intestine of mice was observed beyond one month of sensitization. Passive cutaneous anaphylaxis results confirmed the positive rice allergy in the mouse model. Conclusions We introduced a BALB/c mouse model of rice allergy with simple oral sensitization without the use of adjuvant. This model would serve as a useful tool for further analysis on the immunopathogenic mechanisms of the various rice allergens, for the evaluation of the hypersensitivity of rice or other cereal grains, and to serve as a platform for the development of immunotherapies against rice allergens. PMID:21605393

Anosmia in dementia is associated with Lewy bodies rather than Alzheimer's pathology

PubMed Central

McShane, R; Nagy, Z; Esiri, M; King, E; Joachim, C; Sullivan, N; Smith, A

2001-01-01

OBJECTIVES—To assess olfactory function of patients with dementia. Odour detection ability is impaired in clinical Parkinson's disease. Evidence of impaired detection in patients with clinically diagnosed Alzheimer's disease is inconsistent. No studies of olfaction have been neuropathologically validated.
METHODS—The olfactory function of 92 patients with dementia and 94 controls was assessed using a simple bedside test as part of the Oxford Project To Investigate Memory and Ageing (OPTIMA). Neuropathological assessment was made of cortical Lewy bodies and substantia nigra (SN) cell counts and of Alzheimer's disease in all 92 patients, 22 of whom had SN Lewy bodies and 43 of whom had only Alzheimer's disease.
RESULTS—Patients with Lewy bodies were more likely to be anosmic than those with Alzheimer's disease or controls. Patients with Alzheimer's disease were not more likely to be anosmic than controls. Nor was anosmia associated with degree of neurofibrillary tangles, as assessed by Braak stage. Among subjects with Lewy bodies, overall cortical Lewy body scores and Lewy body density in the cingulate were higher in those who were anosmic. Consensus clinical criteria for dementia with Lewy bodies had a sensitivity of 64% and specificity of 89%. In the absence of definite Alzheimer's disease, the criteria had sensitivity of 100%. In patients with definite Alzheimer's disease, anosmia was slightly more sensitive (55%) than the consensus criteria (33%). However, the addition of anosmia to the consensus criteria did not improve their overall performance.
CONCLUSION—Dementia with Lewy bodies is associated with impaired odour detection. Misdiagnosis may have accounted for some previous reports of impaired odour detection in Alzheimer's disease. Simple but more sensitive tests of anosmia are required if they are to be clinically useful in identifying patients with dementia with Lewy bodies.

 PMID:11385006

Urinary spot albumin:creatinine ratio for documenting proteinuria in women with preeclampsia.

PubMed

Huang, Qitao; Gao, Yunfei; Yu, Yanhong; Wang, Wei; Wang, Shuoshi; Zhong, Mei

2012-01-01

To assess whether a single urinary spot urinary albumin:creatinine ratio (ACR) can be used to estimate 24-hour urinary protein excretion in women with preeclampsia. ACR and 24-hour urinary protein excretion were measured in 50 consecutive patients with preeclampsia. ACR was determined in a spot midstream urine sample and the amount of protein excretion was quantified in a 24-hour urine collection performed the following day. The correlation between the spot ACR and 24-hour urine protein excretion was assessed, and the diagnostic value of ACR was expressed in terms of specificity and sensitivity. Receiver operating characteristic curve analysis was used to determine the best cutoff values of the spot ACR for mild preeclampsia (proteinuria ≥ 0.3 g/24 h) and severe preeclampsia (defined in China as proteinuria ≥ 2 g/24 h). A strong correlation was evident between the spot ACR and 24-hour urinary protein excretion (r = .938; P < .001). The optimal spot ACR cutoff point was 22.8 mg/mmol for 0.3 g/24 h of protein excretion (mild preeclampsia) with a sensitivity and specificity of 82.4% and 99.4%, respectively, and 155.6 mg/mmol for 2 g/24 h of protein excretion (severe preeclampsia) with a sensitivity and specificity of 90.6% and 99.6%, respectively. Compared with 24-hour urinary protein excretion, the spot urinary ACR may be a simple, convenient, and accurate indicator of significant proteinuria in women with preeclampsia.

[Accuracy of three methods for the rapid diagnosis of oral candidiasis].

PubMed

Lyu, X; Zhao, C; Yan, Z M; Hua, H

2016-10-09

Objective: To explore a simple, rapid and efficient method for the diagnosis of oral candidiasis in clinical practice. Methods: Totally 124 consecutive patients with suspected oral candidiasis were enrolled from Department of Oral Medicine, Peking University School and Hospital of Stomatology, Beijing, China. Exfoliated cells of oral mucosa and saliva or concentrated oral rinse) obtained from all participants were tested by three rapid smear methods(10% KOH smear, gram-stained smear, Congo red stained smear). The diagnostic efficacy(sensitivity, specificity, Youden's index, likelihood ratio, consistency, predictive value and area under curve(AUC) of each of the above mentioned three methods was assessed by comparing the results with the gold standard(combination of clinical diagnosis, laboratory diagnosis and expert opinion). Results: Gram-stained smear of saliva(or concentrated oral rinse) demonstrated highest sensitivity(82.3%). Test of 10%KOH smear of exfoliated cells showed highest specificity(93.5%). Congo red stained smear of saliva(or concentrated oral rinse) displayed highest diagnostic efficacy(79.0% sensitivity, 80.6% specificity, 0.60 Youden's index, 4.08 positive likelihood ratio, 0.26 negative likelihood ratio, 80% consistency, 80.3% positive predictive value, 79.4% negative predictive value and 0.80 AUC). Conclusions: Test of Congo red stained smear of saliva(or concentrated oral rinse) could be used as a point-of-care tool for the rapid diagnosis of oral candidiasis in clinical practice. Trial registration: Chinese Clinical Trial Registry, ChiCTR-DDD-16008118.

Correlations between serum trypsinogen-2 and pancreatic cancer.

PubMed

Cao, Jianbiao; Xia, Changhong; Cui, Tingting; Guo, Hanbin; Li, Haoran; Ren, Yongqiang; Wang, Shuai

2015-01-01

To investigate associations be- tween serum trypsinogen-2, pancreatitis and pancreatic cancer (PC) and determine cutoff values for PC diagnosis. We recruited 88 patients from Internal Medicine/Surgical Departments of General Military Hospital of Beijing PLA between 12/2009 and 6/2010. Serum samples were collected preoperatively from 23 PC patients, 30 pancreatitis patients and 35 healthy controls. Enzyme-linked immunosorbent assay was used to detect trypsinogen-2 semiquantitatively. Serum trypsinogen-2 levels of PC and pancreatitis patients were significantly higher than those of controls (51.2 ± 80.3, 107.7 ± 98.1 vs. 1.0 ± 0.5, p = 0.03, p < 0.001) and significantly higher in pancreatitis vs. PC patients (107.7 ± 98.1 vs. 51.2 ± 80.3, p = 0.01). Higher Balthazar CT grades correlated with higher trypsinogen-2 in pancreatitis group. ROC curves for trypsinogen-2 revealed optimal cutoff value 1.8 as lower PC detection limit with 95.7% sensitivity and 91.4% specificity, and optimal cutoff value 19.9 for upper PC detection limit with 87.0% sensitivity and 97.1% specificity. Trypsinogen-2 levels correlated with pancreatic injury level. An AUC of 0.73 (95% Cl: 0.59-0.84, p = 0.002) distinguished PC from pancreatitis. Serum trypsinogen-2 is associated with PC and pancreatitis. Levels between 1.8 μg/L and 19.9 μg/L strongly suggest PC. Detection of serum trypsinogen-2 may provide simple, sensitive, specific non-invasive initial screening for early PC diagnosis.

Comparison of immunohistochemistry and polymerase chain reaction for detection of West Nile virus in naturally infected dead birds.

PubMed

Sandhu, Tejbir; Sidhu, Dalbinder; Dhillon, Major; Fang, Ying

2010-10-04

Credible vector-borne disease surveillance programs, especially in developing countries with limited resources, must include diagnostic tests that are efficient, inexpensive and simple and safe to administer while maintaining high levels of sensitivity and specificity. Since immunohistochemistry (IHC) includes most of these features, its sensitivity, specificity, predictive positive value (PPV) and predictive negative value (PNV) for West Nile virus (WNv) screening were compared to those of the gold standard, RT-PCR testing of kidney tissue in dead birds. IHC and RT-PCR were performed for WNv antigen on 41 dead birds (belonging to five orders) collected from the northwest region of the Riverside County of California. Fixed tissue sections were screened by IHC using polyclonal antibodies, and frozen kidney tissues were tested with RT-PCR. Kidney screening with IHC showed sensitivity, specificity, PPV and NPV of 95.45%, 73.68%, 80.77% and 93.33%, respectively. Based on WNv screening of kidney tissue, IHC and RT-PCR were in agreement with 95.45% (21/22) for positive dead birds and were in 100% (22/22) agreement when multi-organ screening by IHC was performed. The present study showed that IHC is as equally effective as RT-PCR in screening for WNv in dead birds. Therefore, IHC can effectively serve as a competent screening technique for those disease surveillance agencies that lack expensive RT-PCR technology while promoting safer biohazardous conditions, except at the initial stage of tissue collection.

The role of lung imaging in pulmonary embolism

PubMed Central

Mishkin, Fred S.; Johnson, Philip M.

1973-01-01

The advantages of lung scanning in suspected pulmonary embolism are its diagnostic sensitivity, simplicity and safety. The ability to delineate regional pulmonary ischaemia, to quantitate its extent and to follow its response to therapy provides valuable clinical data available by no other simple means. The negative scan effectively excludes pulmonary embolism but, although certain of its features favour the diagnosis of embolism, the positive scan inherently lacks specificity and requires angiographic confirmation when embolectomy, caval plication or infusion of a thrombolytic agent are contemplated. The addition of simple ventilation imaging techniques with radioxenon overcomes this limitation by providing accurate analog estimation or digital quantitation of regional ventilation: perfusion (V/Q) ratios fundamental to understanding the pathophysiologic consequences of embolism and other diseases of the lung. ImagesFig. 1Fig. 2Fig. 3Fig. 4Fig. 5Fig. 6Fig. 7p495-bFig. 8Fig. 9Fig. 10Fig. 11Fig. 12Fig. 13 PMID:4602128

Development and validation of a reversed-phase fluorescence HPLC method for determination of bucillamine in human plasma using pre-column derivatization with monobromobimane.

PubMed

Lee, Kang Choon; Chun, Young Goo; Kim, Insoo; Shin, Beom Soo; Park, Eun-Seok; Yoo, Sun Dong; Youn, Yu Seok

2009-07-15

A simple, specific and sensitive derivatization with monobromobimane (mBrB) and the corresponding HPLC-fluorescence quantitation method for the analysis of bucillamine in human plasma was developed and validated. The analytical procedure involves a simple protein precipitation, pre-column fluorescence derivatization, and separation by reversed-phase high performance liquid chromatography (RP-HPLC). The calibration curve showed good linearity over a wide concentration range (50 ng/mL to 10 microg/mL) in human plasma (r(2)=0.9998). The lower limit of quantitation (LLOQ) was 50 ng/mL. The average precision and accuracy at LLOQ were within 6.3% and 107.6%, respectively. This method was successfully applied to a pharmacokinetic study after oral administration of a dose (300 mg) of bucillamine to 20 healthy Korean volunteers.

[Microbiology--laboratory examinations for bacterias].

PubMed

Hen, Renjun; Imafuku, Yuji; Yoshida, Hiroshi

2002-11-01

As it has been required to identify pathogenic microbes in shorter times, simple and rapid methods have been developed and used. Here, we summarized the present situation of rapid diagnostic testing in clinical microbiology in Japan, and also presented our results on PBP2' detection. The rapid test kits available in Japan for E. coli, Helicobacter pylori, Salmonella, Streptococcus and Staphylococcus aureus were described. Rapid examination methods are based mainly on immunologic reactions, which included slide agglutination using latex particle, immunochromatography and ELISA. Times required for the identification are 10 to 15 minutes. Moreover, rapid test kits employing PCR are also marketed. Further, we evaluated MRSA-LA "Seiken" which is a rapid detection kit for PBP2' produced by MRSA. The test was shown to be highly sensitive and specific. For the rapid identification of pathogenic microbes, simple and rapid test kits described here will be used more in clinical diagnosis.

A neural circuit mechanism for regulating vocal variability during song learning in zebra finches.

PubMed

Garst-Orozco, Jonathan; Babadi, Baktash; Ölveczky, Bence P

2014-12-15

Motor skill learning is characterized by improved performance and reduced motor variability. The neural mechanisms that couple skill level and variability, however, are not known. The zebra finch, a songbird, presents a unique opportunity to address this question because production of learned song and induction of vocal variability are instantiated in distinct circuits that converge on a motor cortex analogue controlling vocal output. To probe the interplay between learning and variability, we made intracellular recordings from neurons in this area, characterizing how their inputs from the functionally distinct pathways change throughout song development. We found that inputs that drive stereotyped song-patterns are strengthened and pruned, while inputs that induce variability remain unchanged. A simple network model showed that strengthening and pruning of action-specific connections reduces the sensitivity of motor control circuits to variable input and neural 'noise'. This identifies a simple and general mechanism for learning-related regulation of motor variability.

Colorimetric Detection of Plasmodium vivax in Urine Using MSP10 Oligonucleotides and Gold Nanoparticles

PubMed Central

Alnasser, Yossef; Ferradas, Cusi; Clark, Taryn; Calderon, Maritza; Gurbillon, Alejandro; Gamboa, Dionicia; McKakpo, Uri S.; Quakyi, Isabella A.; Bosompem, Kwabena M.; Sullivan, David J.; Vinetz, Joseph M.; Gilman, Robert H.

2016-01-01

Plasmodium vivax is the most prevalent cause of human malaria in the world and can lead to severe disease with high potential for relapse. Its genetic and geographic diversities make it challenging to control. P. vivax is understudied and to achieve control of malaria in endemic areas, a rapid, accurate, and simple diagnostic tool is necessary. In this pilot study, we found that a colorimetric system using AuNPs and MSP10 DNA detection in urine can provide fast, easy, and inexpensive identification of P. vivax. The test exhibited promising sensitivity (84%), high specificity (97%), and only mild cross-reactivity with P. falciparum (21%). It is simple to use, with a visible color change that negates the need for a spectrometer, making it suitable for use in austere conditions. Using urine eliminates the need for finger-prick, increasing both the safety profile and patient acceptance of this model. PMID:27706158

Reliability and validity of the work and social adjustment scale in phobic disorders.

PubMed

Mataix-Cols, David; Cowley, Amy J; Hankins, Matthew; Schneider, Andreas; Bachofen, Martin; Kenwright, Mark; Gega, Lina; Cameron, Rachel; Marks, Isaac M

2005-01-01

The Work and Social Adjustment Scale (WSAS) is a simple widely used 5-item measure of disability whose psychometric properties need more analysis in phobic disorders. The reliability, factor structure, validity, and sensitivity to change of the WSAS were studied in 205 phobic patients (73 agoraphobia, 62 social phobia, and 70 specific phobia) who participated in various open and randomized trials of self-exposure therapy. Internal consistency of the WSAS was excellent in all phobics pooled and in agoraphobics and social phobics separately. Principal components analysis extracted a single general factor of disability. Specific phobics gave less consistent ratings across WSAS items, suggesting that some items were less relevant to their problem. Internal consistency was marginally higher for self-ratings than clinician ratings of the WSAS. Self-ratings and clinician ratings correlated highly though patients tended to rate themselves as more disabled than clinicians did. WSAS total scores reflected differences in phobic severity and improvement with treatment. The WSAS is a valid, reliable, and change-sensitive measure of work/social and other adjustment in phobic disorders, especially in agoraphobia and social phobia.

Rapid and label-free detection of protein a by aptamer-tethered porous silicon nanostructures.

PubMed

Urmann, Katharina; Reich, Peggy; Walter, Johanna-Gabriela; Beckmann, Dieter; Segal, Ester; Scheper, Thomas

2017-09-10

Protein A, which is secreted by and displayed on the cell membrane of Staphylococcus aureus is an important biomarker for S. aureus. Thus, its rapid and specific detection may facilitate the pathogen identification and initiation of proper treatment. Herein, we present a simple, label-free and rapid optical biosensor enabling specific detection of protein A. Protein A-binding aptamer serves as the capture probe and is immobilized onto a nanostructured porous silicon thin film, which serves as the optical transducer element. We demonstrate high sensitivity of the biosensor with a linear detection range between 8 and 23μM. The apparent dissociation constant was determined as 13.98μM and the LoD is 3.17μM. Harnessing the affinity between protein A and antibodies, a sandwich assay format was developed to amplify the optical signal associated with protein A capture by the aptamer. Using this approach, we increase the sensitivity of the biosensor, resulting in a three times lower LoD. Copyright © 2017 Elsevier B.V. All rights reserved.

Turbidimetric Method for the Assay of Antiviral Antibodies

PubMed Central

Dandliker, W. B.; de Saussure, V. A.; Grow, T. E.

1969-01-01

A rapid, simple assay method has been developed for antiviral antibodies. The technique has been applied to antisera, immune γ-globulins, and immunospecifically purified antibody for two strains of influenza virus, Asian 305 and PR8, and to antisera to tobacco mosaic virus. Turbidity changes due to the specific interaction of a virus with its antibody were measured by the increase in optical density in a sensitive wavelength region, e.g., 436 nm. Successful application of the method required that nonspecific effects which give rise to turbidity changes be eliminated. This was accomplished by proper choice of ionic strength (0.3 m) and pH (5.5), and by the addition of normal serum or serum albumin to the virus before contact with the antibody. Sensitivity of the method allowed quantitation of antibody down to the level of 10 μg of antibody protein per ml. The specificity of the reaction causing the turbidity change was established by experiments which showed that precipitation of virus-antibody complexes removed the reactive component in the serum, and by the absence of turbidity changes for nonspecific pairs (virus plus unrelated antisera). PMID:4181163

Long-term outcome in patients with germ cell tumours treated with POMB/ACE chemotherapy: comparison of commonly used classification systems of good and poor prognosis.

PubMed Central

Hitchins, R. N.; Newlands, E. S.; Smith, D. B.; Begent, R. H.; Rustin, G. J.; Bagshawe, K. D.

1989-01-01

We analysed outcome in 206 consecutive male patients treated for metastatic non-seminomatous germ cell tumour (NSGCT) of testicular or extragonadal origin treated with the POMB/ACE (cisplatin, vincristine, methotrexate, bleomycin, actinomycin D, cyclophosphamide, etoposide) regimen after division into prognostic groups by commonly used clinical classification systems and definitions of adverse prognosis. The adverse prognostic groups of all classification systems and definitions examined showed similar, but only moderate, sensitivity (71-81%) and specificity (52-56%) in predicting death. A simple definition of poor prognosis based on raised initial levels of serum tumour markers alpha fetoprotein (aFP) and human chorionic gonadotrophin (hCG) proved at least as useful (sensitivity 80%, specificity 55%) as other more complicated systems in predicting failure to achieve long-term survival. Comparison of survival between ultra-high dose cisplatin-based combination chemotherapy and patients treated with POMB/ACE shows no advantage from this more toxic approach. This suggests that good results in adverse prognosis patients can be achieved using conventional dose regimens administered intensively. PMID:2467682

pH-sensitive nanocargo based on smart polymer functionalized graphene oxide for site-specific drug delivery.

PubMed

Kavitha, Thangavelu; Abdi, Syed Izhar Haider; Park, Soo-Young

2013-04-14

Graphene oxide (GO) was functionalized covalently with pH-sensitive poly(2-(diethylamino) ethyl methacrylate) (PDEA) by surface-initiated in situ atom transfer radical polymerization. The structure of the PDEA-grafted GO (GO-PDEA) were examined by Fourier-transform infrared spectroscopy, proton nuclear magnetic resonance spectroscopy, X-ray photoelectron spectroscopy, thermogravimetric analysis and atomic force microscopy. The grafted PDEA endowed the GO sheets with good solubility and stability in physiological solutions. Simple physisorption by π-π stacking and hydrophobic interactions on GO-PDEA can be used to load camptothecin (CPT), a widely used water-insoluble cancer drug. The loaded CPT was released only at the lower (acidic) pH normally found in a tumor environment but not in basic and neutral pH. GO-PDEA did not show practical toxicity to N2a cancer cells but the GO-PDEA-CPT complex exhibited high potency in killing N2a cancer cells in vitro. These results suggest that the GO-PDEA nanocargo carrier might be a promising material for site-specific anticancer drug delivery and controlled release.

Compensatory Limb Use and Behavioral Assessment of Motor Skill Learning Following Sensorimotor Cortex Injury in a Mouse Model of Ischemic Stroke

PubMed Central

Kerr, Abigail L.; Tennant, Kelly A.

2014-01-01

Mouse models have become increasingly popular in the field of behavioral neuroscience, and specifically in studies of experimental stroke. As models advance, it is important to develop sensitive behavioral measures specific to the mouse. The present protocol describes a skilled motor task for use in mouse models of stroke. The Pasta Matrix Reaching Task functions as a versatile and sensitive behavioral assay that permits experimenters to collect accurate outcome data and manipulate limb use to mimic human clinical phenomena including compensatory strategies (i.e., learned non-use) and focused rehabilitative training. When combined with neuroanatomical tools, this task also permits researchers to explore the mechanisms that support behavioral recovery of function (or lack thereof) following stroke. The task is both simple and affordable to set up and conduct, offering a variety of training and testing options for numerous research questions concerning functional outcome following injury. Though the task has been applied to mouse models of stroke, it may also be beneficial in studies of functional outcome in other upper extremity injury models. PMID:25045916

Development of a rapid assay to detect the jellyfish Cyanea nozakii using a loop-mediated isothermal amplification method.

PubMed

Liu, Zhongyuan; Dong, Zhijun; Liu, Dongyan

2016-07-01

Blooms of the harmful jellyfish Cyanea nozakii, which are a severe nuisance to fisheries and tourisms, frequently occur in the northern East China Sea, Yellow Sea, and Bohai Sea. To provide early warning of this species, a simple and effective molecular method for identifying C. nozakii was developed using the loop-mediated isothermal amplification method (LAMP). The LAMP assay is highly specific and uses a set of four primers that target six different regions on the mitochondrial cytochrome c oxidase subunit I (COI) gene of C. nozakii. The amplification conditions, including the dNTP and betaine concentrations, the inner primer to outer primer concentration ratio, reaction time and temperature, were optimized. The LAMP assay amplified DNA extracted from tissue samples of C. nozakii but did not amplify DNA from other common scyphozoans and hydrozoans collected in the same region. In addition, the LAMP assay was more sensitive than conventional PCR. Therefore, the established LAMP assay is a sensitive, specific, fast, and easily performed method for detection of C. nozakii at different stages in their life cycle.

Rapid and sensitive detection of Little cherry virus 2 using isothermal reverse transcription-recombinase polymerase amplification.

PubMed

Mekuria, Tefera A; Zhang, Shulu; Eastwell, Kenneth C

2014-09-01

Little cherry virus 2 (LChV2) (genus Ampelovirus) is the primary causal agent of little cherry disease (LCD) in sweet cherry (Prunus avium) in North America and other parts of the world. This mealybug-transmitted virus does not induce significant foliar symptoms in most sweet cherry cultivars, but does cause virus-infected trees to yield unevenly ripened small fruits with poor flavor. Most fruits from infected trees are unmarketable. In the present study, an isothermal reverse transcription-recombinase polymerase amplification (RT-RPA) technique was developed using LChV2 coat protein specific primers and probe. Detection of terminally labeled amplicons was achieved with a high affinity lateral flow strip. The RT-RPA is confirmed to be simple, fast, and specific. In comparison, although it retains the sensitivity of RT-PCR, it is a more cost-effective procedure. RT-RPA will be a very useful tool for detecting LChV2 from crude extracts in any growth stage of sweet cherry from field samples. Copyright © 2014 The Authors. Published by Elsevier B.V. All rights reserved.

A novel immunoassay using recombinant allergens simplifies peanut allergy diagnosis.

PubMed

Codreanu, F; Collignon, O; Roitel, O; Thouvenot, B; Sauvage, C; Vilain, A-C; Cousin, M-O; Decoster, A; Renaudin, J-M; Astier, C; Monnez, J-M; Vallois, P; Morisset, M; Moneret-Vautrin, D-A; Brulliard, M; Ogier, V; Castelain, M-C; Kanny, G; Bihain, B E; Jacquenet, S

2011-01-01

Double-blind placebo-controlled food challenge (DBPCFC) is currently considered the gold standard for peanut allergy diagnosis. However, this procedure that requires the hospitalization of patients, mostly children, in specialized centers for oral exposure to allergens may cause severe reactions requiring emergency measures. Thus, a simpler and safer diagnosis procedure is needed. The aim of this study was to evaluate the diagnostic performance of a new set of in vitro blood tests for peanut allergy. The levels of IgE directed towards peanut extract and recombinant peanut allergens Ara h 1, Ara h 2, Ara h 3, Ara h 6, Ara h 7, and Ara h 8 were measured in 3 groups of patients enrolled at 2 independent centers: patients with proven peanut allergy (n=166); pollen-sensitized subjects without peanut allergy (n=61), and control subjects without allergic disease (n=10). Seventy-nine percent of the pollen-sensitized patients showed IgE binding to peanut, despite their tolerance to peanut. In contrast, combining the results of specific IgE to peanut extract and to recombinant Ara h 2 and Ara h 6 yielded a peanut allergy diagnosis with a 98% sensitivity and an 85% specificity at a positivity threshold of 0.10 kU/l. Use of a threshold of 0.23 kU/l for recombinant Ara h 2 increased specificity (96%) at the cost of sensitivity (93%). A simple blood test can be used to diagnose peanut allergy with a high level of precision. However, DBPCFC will remain useful for the few cases where immunological and clinical observations yield conflicting results. Copyright © 2010 S. Karger AG, Basel.

Comparison of methods for determination of volatile organic compounds in drinking water.

PubMed

Golfinopoulos, S K; Lekkas, T D; Nikolaou, A D

2001-10-01

Comparison of four methods including liquid-liquid extraction (LLE), direct aqueous injection (DAI), purge and trap (PAT) and head space (HS) were carried out in this work for determination of volatile organic compounds (VOCs) including trihalomethanes (THMs) in drinking water. This comparison is made especially to show the advantages and disadvantages and specifically the different detection limits (DL) that can be obtained for a given type of analysis. LLE is applicable only for determination of the THMs concentrations, while DAI, PAT, HS methods with different DL each of them are applicable for all VOCs, with PAT to be the most sensitive. Sampling apparatus and procedure for all these methods except of PAT are very simple and easy, but possible disadvantages for LLE and DAI are the low sensitivity and especially the detection only of THMs with LLE.

Measurement of salivary cortisol by a chemiluminescent organic-based immunosensor.

PubMed

Pires, N M M; Dong, T

2014-01-01

A highly sensitive chemiluminescent immunoassay (CLIA) using a sensitive organic photodetector was developed to detect human cortisol, an important biomarker for stress-related diseases. The developed CLIA was performed onto gold-coated glass chips, on which anti-cortisol antibodies were immobilised and chemiluminescent horseradish peroxidase-luminol-peroxide reactions were generated. Using cortisol-spiked artificial saliva samples, the CLIA biosensor showed a linear range of detection between 0.1 ng/mL and 175 ng/mL and a detection limit of 80 pg/mL. The sensor response was highly specific to cortisol and did not vary significantly between assays. The results indicate the potential clinical application of the CLIA sensor. Furthermore, the simple layered structure of the organic photodetector may encourage the realisation of integrated optical biosensors for point-of-use measurement of salivary cortisol levels.

Effect of slope errors on the performance of mirrors for x-ray free electron laser applications

DOE PAGES

Pardini, Tom; Cocco, Daniele; Hau-Riege, Stefan P.

2015-12-02

In this work we point out that slope errors play only a minor role in the performance of a certain class of x-ray optics for X-ray Free Electron Laser (XFEL) applications. Using physical optics propagation simulations and the formalism of Church and Takacs [Opt. Eng. 34, 353 (1995)], we show that diffraction limited optics commonly found at XFEL facilities posses a critical spatial wavelength that makes them less sensitive to slope errors, and more sensitive to height error. Given the number of XFELs currently operating or under construction across the world, we hope that this simple observation will help tomore » correctly define specifications for x-ray optics to be deployed at XFELs, possibly reducing the budget and the timeframe needed to complete the optical manufacturing and metrology.« less

A single-index threshold Cox proportional hazard model for identifying a treatment-sensitive subset based on multiple biomarkers.

PubMed

He, Ye; Lin, Huazhen; Tu, Dongsheng

2018-06-04

In this paper, we introduce a single-index threshold Cox proportional hazard model to select and combine biomarkers to identify patients who may be sensitive to a specific treatment. A penalized smoothed partial likelihood is proposed to estimate the parameters in the model. A simple, efficient, and unified algorithm is presented to maximize this likelihood function. The estimators based on this likelihood function are shown to be consistent and asymptotically normal. Under mild conditions, the proposed estimators also achieve the oracle property. The proposed approach is evaluated through simulation analyses and application to the analysis of data from two clinical trials, one involving patients with locally advanced or metastatic pancreatic cancer and one involving patients with resectable lung cancer. Copyright © 2018 John Wiley & Sons, Ltd.

Effect of slope errors on the performance of mirrors for x-ray free electron laser applications.

PubMed

Pardini, Tom; Cocco, Daniele; Hau-Riege, Stefan P

2015-12-14

In this work we point out that slope errors play only a minor role in the performance of a certain class of x-ray optics for X-ray Free Electron Laser (XFEL) applications. Using physical optics propagation simulations and the formalism of Church and Takacs [Opt. Eng. 34, 353 (1995)], we show that diffraction limited optics commonly found at XFEL facilities posses a critical spatial wavelength that makes them less sensitive to slope errors, and more sensitive to height error. Given the number of XFELs currently operating or under construction across the world, we hope that this simple observation will help to correctly define specifications for x-ray optics to be deployed at XFELs, possibly reducing the budget and the timeframe needed to complete the optical manufacturing and metrology.

DNA Repair Defects and Chromosomal Aberrations

NASA Technical Reports Server (NTRS)

Hada, Megumi; George, K. A.; Huff, J. L.; Pluth, J. M.; Cucinotta, F. A.

2009-01-01

Yields of chromosome aberrations were assessed in cells deficient in DNA doublestrand break (DSB) repair, after exposure to acute or to low-dose-rate (0.018 Gy/hr) gamma rays or acute high LET iron nuclei. We studied several cell lines including fibroblasts deficient in ATM (ataxia telangiectasia mutated; product of the gene that is mutated in ataxia telangiectasia patients) or NBS (nibrin; product of the gene mutated in the Nijmegen breakage syndrome), and gliomablastoma cells that are proficient or lacking in DNA-dependent protein kinase (DNA-PK) activity. Chromosomes were analyzed using the fluorescence in situ hybridization (FISH) chromosome painting method in cells at the first division post irradiation, and chromosome aberrations were identified as either simple exchanges (translocations and dicentrics) or complex exchanges (involving >2 breaks in 2 or more chromosomes). Gamma irradiation induced greater yields of both simple and complex exchanges in the DSB repair-defective cells than in the normal cells. The quadratic dose-response terms for both simple and complex chromosome exchanges were significantly higher for the ATM- and NBS-deficient lines than for normal fibroblasts. However, in the NBS cells the linear dose-response term was significantly higher only for simple exchanges. The large increases in the quadratic dose-response terms in these repair-defective cell lines points the importance of the functions of ATM and NBS in chromatin modifications to facilitate correct DSB repair and minimize the formation of aberrations. The differences found between ATM- and NBS-deficient cells at low doses suggest that important questions should with regard to applying observations of radiation sensitivity at high dose to low-dose exposures. For aberrations induced by iron nuclei, regression models preferred purely linear dose responses for simple exchanges and quadratic dose responses for complex exchanges. Relative biological effectiveness (RBE) factors of all of the DNA repair-defective cell lines were smaller than those of normal cells, with the DNA-PK-deficient cells having RBEs near unity. To further investigate the sensitivity differences that were observed in ATM and NBS deficient cells, chromosomal aberrations were analyzed in normal lung fibroblast cells treated with KU-55933 (a specific ATM kinase inhibitor) or Mirin (an Mre11- Rad50-Nbs1 complex inhibitor involved in activation of ATM). We also performed siRNA knockdown of these proteins. Preliminary data indicate that chromosome exchanges increase in cells treated with the specific ATM inhibitor. Possible cytogenetic signatures of acute and low dose-rate gamma irradiation in ATM or nibrin deficient and suppressed cells will be discussed.

Detection of Echinoderm Microtubule Associated Protein Like 4-Anaplastic Lymphoma Kinase Fusion Genes in Non-small Cell Lung Cancer Clinical Samples by a Real-time Quantitative Reverse Transcription Polymerase Chain Reaction Method.

PubMed

Zhao, Jing; Zhao, Jin-Yin; Chen, Zhi-Xia; Zhong, Wei; Li, Long-Yun; Liu, Li-Cheng; Hu, Xiao-Xu; Chen, Wei-Jun; Wang, Meng-Zhao

2016-12-20

Objective To establish a real-time quantitative reverse transcription polymerase chain reaction assay (qRT-PCR) for the rapid, sensitive, and specific detection of echinoderm microtubule associated protein like 4-anaplastic lymphoma kinase (EML4-ALK) fusion genes in non-small cell lung cancer. Methods The specific primers for the four variants of EML4-ALK fusion genes (V1, V2, V3a, and V3b) and Taqman fluorescence probes for the detection of the target sequences were carefully designed by the Primer Premier 5.0 software. Then, using pseudovirus containing EML4-ALK fusion genes variants (V1, V2, V3a, and V3b) as the study objects, we further analyzed the lower limit, sensitivity, and specificity of this method. Finally, 50 clinical samples, including 3 ALK-fluorescence in situ hybridization (FISH) positive specimens, were collected and used to detect EML4-ALK fusion genes using this method. Results The lower limit of this method for the detection of EML4-ALK fusion genes was 10 copies/μl if no interference of background RNA existed. Regarding the method's sensitivity, the detection resolution was as high as 1% and 0.5% in the background of 500 and 5000 copies/μl wild-type ALK gene, respectively. Regarding the method's specificity, no non-specific amplification was found when it was used to detect EML4-ALK fusion genes in leukocyte and plasma RNA samples from healthy volunteers. Among the 50 clinical samples, 47 ALK-FISH negative samples were also negative. Among 3 ALK-FISH positive samples, 2 cases were detected positive using this method, but another was not detected because of the failure of RNA extraction. Conclusion The proposed qRT-PCR assay for the detection of EML4-ALK fusion genes is rapid, simple, sensitive, and specific, which is deserved to be validated and widely used in clinical settings.

Evaluation of modified Alvarado scoring system and RIPASA scoring system as diagnostic tools of acute appendicitis.

PubMed

Shuaib, Abdullah; Shuaib, Ali; Fakhra, Zainab; Marafi, Bader; Alsharaf, Khalid; Behbehani, Abdullah

2017-01-01

Acute appendicitis is the most common surgical condition presented in emergency departments worldwide. Clinical scoring systems, such as the Alvarado and modified Alvarado scoring systems, were developed with the goal of reducing the negative appendectomy rate to 5%-10%. The Raja Isteri Pengiran Anak Saleha Appendicitis (RIPASA) scoring system was established in 2008 specifically for Asian populations. The aim of this study was to compare the modified Alvarado with the RIPASA scoring system in Kuwait population. This study included 180 patients who underwent appendectomies and were documented as having "acute appendicitis" or "abdominal pain" in the operating theatre logbook (unit B) from November 2014 to March 2016. The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), diagnostic accuracy, predicted negative appendectomy and receiver operating characteristic (ROC) curve of the modified Alvarado and RIPASA scoring systems were derived using SPSS statistical software. A total of 136 patients were included in this study according to our criteria. The cut-off threshold point of the modified Alvarado score was set at 7.0, which yielded a sensitivity of 82.8% and a specificity of 56%. The PPV was 89.3% and the NPV was 42.4%. The cut-off threshold point of the RIPASA score was set at 7.5, which yielded a 94.5% sensitivity and an 88% specificity. The PPV was 97.2% and the NPV was 78.5%. The predicted negative appendectomy rates were 10.7% and 2.2% for the modified Alvarado and RIPASA scoring systems, respectively. The negative appendectomy rate decreased significantly, from 18.4% to 10.7% for the modified Alvarado, and to 2.2% for the RIPASA scoring system, which was a significant difference (P<0.001) for both scoring systems. Based on the results of this study, the RIPASA score is a simple scoring system with better sensitivity and specificity than the modified Alvarado scoring system in Asian populations. It consists of 14 clinical parameters that can be obtained from a good patient history, clinical examination and laboratory investigations. The RIPASA scoring system is more accurate and specific than the modified Alvarado scoring system for Kuwait population.

Rapid detection of pandemic influenza in the presence of seasonal influenza

PubMed Central

2010-01-01

Background Key to the control of pandemic influenza are surveillance systems that raise alarms rapidly and sensitively. In addition, they must minimise false alarms during a normal influenza season. We develop a method that uses historical syndromic influenza data from the existing surveillance system 'SERVIS' (Scottish Enhanced Respiratory Virus Infection Surveillance) for influenza-like illness (ILI) in Scotland. Methods We develop an algorithm based on the weekly case ratio (WCR) of reported ILI cases to generate an alarm for pandemic influenza. From the seasonal influenza data from 13 Scottish health boards, we estimate the joint probability distribution of the country-level WCR and the number of health boards showing synchronous increases in reported influenza cases over the previous week. Pandemic cases are sampled with various case reporting rates from simulated pandemic influenza infections and overlaid with seasonal SERVIS data from 2001 to 2007. Using this combined time series we test our method for speed of detection, sensitivity and specificity. Also, the 2008-09 SERVIS ILI cases are used for testing detection performances of the three methods with a real pandemic data. Results We compare our method, based on our simulation study, to the moving-average Cumulative Sums (Mov-Avg Cusum) and ILI rate threshold methods and find it to be more sensitive and rapid. For 1% case reporting and detection specificity of 95%, our method is 100% sensitive and has median detection time (MDT) of 4 weeks while the Mov-Avg Cusum and ILI rate threshold methods are, respectively, 97% and 100% sensitive with MDT of 5 weeks. At 99% specificity, our method remains 100% sensitive with MDT of 5 weeks. Although the threshold method maintains its sensitivity of 100% with MDT of 5 weeks, sensitivity of Mov-Avg Cusum declines to 92% with increased MDT of 6 weeks. For a two-fold decrease in the case reporting rate (0.5%) and 99% specificity, the WCR and threshold methods, respectively, have MDT of 5 and 6 weeks with both having sensitivity close to 100% while the Mov-Avg Cusum method can only manage sensitivity of 77% with MDT of 6 weeks. However, the WCR and Mov-Avg Cusum methods outperform the ILI threshold method by 1 week in retrospective detection of the 2009 pandemic in Scotland. Conclusions While computationally and statistically simple to implement, the WCR algorithm is capable of raising alarms, rapidly and sensitively, for influenza pandemics against a background of seasonal influenza. Although the algorithm was developed using the SERVIS data, it has the capacity to be used at other geographic scales and for different disease systems where buying some early extra time is critical. PMID:21106071

Accuracy of FNAC and CT in the differentiation of benign and malignant parotid tumours in a case series.

PubMed

Gavín-Clavero, Marina A; Usón-Bouthelier, Tomás; Jariod-Ferrer, Úrsula M; Fernández-Larrañaga, Arancha; Pantilie, Bianca; Lobera-Molina, Fernando; Simón-Sanz, M Victoria; Nadal Cristóbal, Bartolomé

Parotid tumours, in addition to the wide variety of types, are histologically complex. Differentiating between benign and malignant tumours in preoperative diagnosis is important in deciding the type of surgery required. Fine needle aspiration cytology (FNAC) is a simple, quick, low-cost, low-invasive and well-tolerated tool used in the preoperative diagnosis of these tumours. we calculated the sensitivity, specificity, predictive positive value (PPV) and negative predictive value (NPV) of FNAC and computed tomography (CT) in the differentiation of benign and malignant parotid tumours operated between 2010 to 2014 in the oral and maxillofacial surgery department of the University Hospital Miguel Servet. The sensitivity of FNAC is 50%, while the specificity is high, at 98.7%. FNAC offers high reliability in the diagnosis of malignant tumours, despite its low sensitivity. However, when the diagnosis is indeterminate or benign, other than pleomorphic adenoma or Whartin tumour, the reliability to exclude malignancy decreases. The low sensitivity of FNAC to differentiate malignant from benign parotid tumours, means that we cannot rule out other diagnostic tests, clinical symptoms and especially the intraoperative vision of each surgeon. Especially when the diagnosis is indeterminate. Nevertheless, it is a technique used in a systematised way and helps in pre-surgical decision-making. Copyright © 2017 Elsevier España, S.L.U. and Sociedad Española de Otorrinolaringología y Cirugía de Cabeza y Cuello. All rights reserved.

Immuno capture PCR for rapid and sensitive identification of pathogenic Bacillus anthracis.

PubMed

Makam, Shivakiran S; Majumder, Saugata; Kingston, Joseph J; Urs, Radhika M; Tuteja, Urmil; Sripathi, Murali H; Batra, Harsh V

2013-12-01

Immuno capture PCR (IPCR) is a technique capable of detecting the pathogens with high specificity and sensitivity. Rapid and accurate detection of Bacillus anthracis was achieved using anti-EA1 antibodies to capture the cells and two primer sets targeting the virulence factors of the pathogen i.e., protective antigen (pag) and capsule (cap) in an IPCR format. Monoclonal antibodies specific to B. anthracis were generated against extractable antigen 1 protein and used as capture antibody onto 96 well polystyrene plates. Following the binding of the pathogen, the DNA extraction was carried out in the well itself and further processed for PCR assay. We compared IPCR described here with conventional duplex PCR using the same primers and sandwich ELISA using the monoclonal antibodies developed in the present study. IPCR was capable of detecting as few as 10 and 100 cfu ml⁻¹ of bacterial cells and spores, respectively. IPCR was found to be 2-3 logs more sensitive than conventional duplex PCR and the sandwich ELISA. The effect of other bacteria and any organic materials on IPCR was also analyzed and found that this method was robust with little change in the sensitivity in the presence of interfering agents. Moreover, we could demonstrate a simple process of microwave treatment for spore disruption which otherwise are resistant to chemical treatments. Also, the IPCR could clearly distinguish the pathogenic and nonpathogenic strains of B. anthracis in the same assay. This can help in saving resources on unnecessary decontamination procedures during false alarms.

Glucose Sensors Based on Microcapsules Containing an Orange/Red Competitive Binding Resonance Energy Transfer Assay

PubMed Central

CHINNAYELKA, SWETHA; McSHANE, and MICHAEL J.

2015-01-01

Fluorescent sensing systems offer the potential for noninvasive monitoring with implantable devices, but they require carrier technologies that provide suitable immobilization, accessibility, and biocompatibility while maintaining adequate response characteristics. A recent development towards this goal is a highly specific and sensitive competitive binding assay for glucose using apo-glucose oxidase (apo-GOx) as the recognition element and dextran as the competing ligand; this has been demonstrated as a glucose sensor system by encapsulating the competitive binding assay in semipermeable microcapsule carriers. This paper describes the extension of this sensor design to longer wavelengths in an attempt to increase the applicability to in vivo monitoring. The glucose sensitivity of the tetramethylrhodamine isothiocyanate-dextran (TD) and cyanine Cy5-apo-GOx (CAG) complexes showed five to 10 times greater specificity for β-D-glucose over other sugars. Microcapsules loaded with TD/CAG complexes exhibited a linear, totally reversible response in the range of 0–720 mg/dL, with a sensitivity (percent change in intensity ratio) of 0.06%/(mg/dL). The decrease in sensitivity observed with the use of longer-wavelength dyes is most likely to be compensated with the deeper penetration of light and reduced tissue scattering. These findings imply that the encapsulation of sensing assay elements in microcapsules is a simple and translatable method for the fabrication of stable biosensors, and optimization of resonance energy transfer pairs and assay component preparation will further improve the response to approach clinically relevant performance. PMID:16800748

Novel and simple electrochemical biosensor monitoring attomolar levels of miRNA-155 in breast cancer.

PubMed

Cardoso, Ana R; Moreira, Felismina T C; Fernandes, Rúben; Sales, M Goreti F

2016-06-15

This work, describes for the first time, a simple biosensing design to yield an ultrasensitive electrochemical biosensor for a cancer biomarker detection, miRNA-155, with linear response down to the attomolar range. MiRNA-155 was selected for being overexpressed in breast cancer. The biosensor was assembled in two stages: (1) the immobilization of the anti-miRNA-155 that was thiol modified on an Au-screen printed electrode (Au-SPE), followed by (2) blocking the areas of non-specific binding with mercaptosuccinic acid. Atomic force microscopy (AFM) and electrochemical techniques including cyclic voltammetry (CV), impedance spectroscopy (EIS) and square wave voltammetry (SWV) confirmed the surface modification of these devices and their ability to hybridize successfully and stably with miRNA-155. The final biosensor provided a sensitive detection of miRNA-155 from 10 aM to 1.0 nM with a low detection limit (LOD) of 5.7 aM in real human serum samples. Good results were obtained in terms of selectivity towards breast cancer antigen CA-15.3 and bovine serum albumin (BSA). Raw fluid extracts from cell-lines of melanoma did not affect the biosensor response (no significant change of the blank), while raw extracts from breast cancer yielded a positive signal against miRNA-155. This simple and sensitive strategy is a promising alternative for simultaneous quantitative analysis of multiple miRNA in physiological fluids for biomedical research and point-of-care (POC) diagnosis. Copyright © 2016 The Authors. Published by Elsevier B.V. All rights reserved.

Loop-mediated isothermal amplification (LAMP) method for detection of genetically modified maize T25.

PubMed

Xu, Junyi; Zheng, Qiuyue; Yu, Ling; Liu, Ran; Zhao, Xin; Wang, Gang; Wang, Qinghua; Cao, Jijuan

2013-11-01

The loop-mediated isothermal amplification (LAMP) assay indicates a potential and valuable means for genetically modified organism (GMO) detection especially for its rapidity, simplicity, and low cost. We developed and evaluated the specificity and sensitivity of the LAMP method for rapid detection of the genetically modified (GM) maize T25. A set of six specific primers was successfully designed to recognize six distinct sequences on the target gene, including a pair of inner primers, a pair of outer primers, and a pair of loop primers. The optimum reaction temperature and time were verified to be 65°C and 45 min, respectively. The detection limit of this LAMP assay was 5 g kg(-1) GMO component. Comparative experiments showed that the LAMP assay was a simple, rapid, accurate, and specific method for detecting the GM maize T25.

Geoelectrical mapping and groundwater contamination

NASA Astrophysics Data System (ADS)

Blum, Rainer

Specific electrical resistivity of near-surface materials is mainly controlled by the groundwater content and thus reacts extremely sensitive to any change in the ion content. Geoelectric mapping is a well-established, simple, and inexpensive technique for observing areal distributions of apparent specific electrical resistivities. These are a composite result of the true resistivities in the underground, and with some additional information the mapping of apparent resistivities can help to delineate low-resistivity groundwater contaminations, typically observed downstream from sanitary landfills and other waste sites. The presence of other good conductors close to the surface, mainly clays, is a serious noise source and has to be sorted out by supporting observations of conductivities in wells and geoelectric depth soundings. The method may be used to monitor the extent of groundwater contamination at a specific time as well as the change of a contamination plume with time, by carrying out repeated measurements. Examples for both are presented.

Loop-mediated isothermal amplification (LAMP) method for detection of genetically modified maize T25

PubMed Central

Xu, Junyi; Zheng, Qiuyue; Yu, Ling; Liu, Ran; Zhao, Xin; Wang, Gang; Wang, Qinghua; Cao, Jijuan

2013-01-01

The loop-mediated isothermal amplification (LAMP) assay indicates a potential and valuable means for genetically modified organism (GMO) detection especially for its rapidity, simplicity, and low cost. We developed and evaluated the specificity and sensitivity of the LAMP method for rapid detection of the genetically modified (GM) maize T25. A set of six specific primers was successfully designed to recognize six distinct sequences on the target gene, including a pair of inner primers, a pair of outer primers, and a pair of loop primers. The optimum reaction temperature and time were verified to be 65°C and 45 min, respectively. The detection limit of this LAMP assay was 5 g kg−1 GMO component. Comparative experiments showed that the LAMP assay was a simple, rapid, accurate, and specific method for detecting the GM maize T25. PMID:24804053

Peregrine

PubMed Central

Langevin, Stanley A.; Bent, Zachary W.; Solberg, Owen D.; Curtis, Deanna J.; Lane, Pamela D.; Williams, Kelly P.; Schoeniger, Joseph S.; Sinha, Anupama; Lane, Todd W.; Branda, Steven S.

2013-01-01

Use of second generation sequencing (SGS) technologies for transcriptional profiling (RNA-Seq) has revolutionized transcriptomics, enabling measurement of RNA abundances with unprecedented specificity and sensitivity and the discovery of novel RNA species. Preparation of RNA-Seq libraries requires conversion of the RNA starting material into cDNA flanked by platform-specific adaptor sequences. Each of the published methods and commercial kits currently available for RNA-Seq library preparation suffers from at least one major drawback, including long processing times, large starting material requirements, uneven coverage, loss of strand information and high cost. We report the development of a new RNA-Seq library preparation technique that produces representative, strand-specific RNA-Seq libraries from small amounts of starting material in a fast, simple and cost-effective manner. Additionally, we have developed a new quantitative PCR-based assay for precisely determining the number of PCR cycles to perform for optimal enrichment of the final library, a key step in all SGS library preparation workflows. PMID:23558773

Query-seeded iterative sequence similarity searching improves selectivity 5–20-fold

PubMed Central

Li, Weizhong; Lopez, Rodrigo

2017-01-01

Abstract Iterative similarity search programs, like psiblast, jackhmmer, and psisearch, are much more sensitive than pairwise similarity search methods like blast and ssearch because they build a position specific scoring model (a PSSM or HMM) that captures the pattern of sequence conservation characteristic to a protein family. But models are subject to contamination; once an unrelated sequence has been added to the model, homologs of the unrelated sequence will also produce high scores, and the model can diverge from the original protein family. Examination of alignment errors during psiblast PSSM contamination suggested a simple strategy for dramatically reducing PSSM contamination. psiblast PSSMs are built from the query-based multiple sequence alignment (MSA) implied by the pairwise alignments between the query model (PSSM, HMM) and the subject sequences in the library. When the original query sequence residues are inserted into gapped positions in the aligned subject sequence, the resulting PSSM rarely produces alignment over-extensions or alignments to unrelated sequences. This simple step, which tends to anchor the PSSM to the original query sequence and slightly increase target percent identity, can reduce the frequency of false-positive alignments more than 20-fold compared with psiblast and jackhmmer, with little loss in search sensitivity. PMID:27923999

A virus resonance light scattering sensor based on mussel-inspired molecularly imprinted polymers for high sensitive and high selective detection of Hepatitis A Virus.

PubMed

Yang, Bin; Gong, Hang; Chen, Chunyan; Chen, Xiaoming; Cai, Changqun

2017-01-15

We described a novel resonance light scattering (RLS) sensor for the specific recognition of trace quantities of Hepatitis A Virus (HAV); the sensor was based on a mussel-inspired hepatitis molecularly imprinted polymer. As a recognition element, polydopamine (PDA)-coated totivirus-imprinted polymer was introduced on the surface of SiO 2 nanoparticles (virus-imprinted SiO 2 @PDA NPs) using an efficient one-step synthesis method. The target virus was selectively captured by the imprinted polymer films, thereby increasing the RLS intensity. A simple fluorescence spectrophotometer was employed to measure the changes in the intensity. The enhanced RLS intensity (∆I RLS ) was proportional to the concentration of HAV in the range of 0.04-6.0nmol∙L -1 , with a low limit of detection of 8.6pmol∙L -1 . The selectivity study confirmed that the resultant HAV-imprinted SiO 2 @PDA NPs possessed high selectivity for HAV. The sensor was successfully applied for the direct detection of additional HAV from a 20,000-fold dilution of human serum. The proposed strategy is simple, eco-friendly, highly selective, and sensitive. Copyright © 2016 Elsevier B.V. All rights reserved.

Temperament trait of sensory processing sensitivity moderates cultural differences in neural response.

PubMed

Aron, Arthur; Ketay, Sarah; Hedden, Trey; Aron, Elaine N; Rose Markus, Hazel; Gabrieli, John D E

2010-06-01

This study focused on a possible temperament-by-culture interaction. Specifically, it explored whether a basic temperament/personality trait (sensory processing sensitivity; SPS), perhaps having a genetic component, might moderate a previously established cultural difference in neural responses when making context-dependent vs context-independent judgments of simple visual stimuli. SPS has been hypothesized to underlie what has been called inhibitedness or reactivity in infants, introversion in adults, and reactivity or responsivness in diverse animal species. Some biologists view the trait as one of two innate strategies-observing carefully before acting vs being first to act. Thus the central characteristic of SPS is hypothesized to be a deep processing of information. Here, 10 European-Americans and 10 East Asians underwent functional magnetic resonance imaging while performing simple visuospatial tasks emphasizing judgments that were either context independent (typically easier for Americans) or context dependent (typically easier for Asians). As reported elsewhere, each group exhibited greater activation for the culturally non-preferred task in frontal and parietal regions associated with greater effort in attention and working memory. However, further analyses, reported here for the first time, provided preliminary support for moderation by SPS. Consistent with the careful-processing theory, high-SPS individuals showed little cultural difference; low-SPS, strong culture differences.

Temperament trait of sensory processing sensitivity moderates cultural differences in neural response

PubMed Central

Ketay, Sarah; Hedden, Trey; Aron, Elaine N.; Rose Markus, Hazel; Gabrieli, John D. E.

2010-01-01

This study focused on a possible temperament-by-culture interaction. Specifically, it explored whether a basic temperament/personality trait (sensory processing sensitivity; SPS), perhaps having a genetic component, might moderate a previously established cultural difference in neural responses when making context-dependent vs context-independent judgments of simple visual stimuli. SPS has been hypothesized to underlie what has been called inhibitedness or reactivity in infants, introversion in adults, and reactivity or responsivness in diverse animal species. Some biologists view the trait as one of two innate strategies—observing carefully before acting vs being first to act. Thus the central characteristic of SPS is hypothesized to be a deep processing of information. Here, 10 European-Americans and 10 East Asians underwent functional magnetic resonance imaging while performing simple visuospatial tasks emphasizing judgments that were either context independent (typically easier for Americans) or context dependent (typically easier for Asians). As reported elsewhere, each group exhibited greater activation for the culturally non-preferred task in frontal and parietal regions associated with greater effort in attention and working memory. However, further analyses, reported here for the first time, provided preliminary support for moderation by SPS. Consistent with the careful-processing theory, high-SPS individuals showed little cultural difference; low-SPS, strong culture differences. PMID:20388694

Lesion size affects diagnostic performance of IOTA logistic regression models, IOTA simple rules and risk of malignancy index in discriminating between benign and malignant adnexal masses.

PubMed

Di Legge, A; Testa, A C; Ameye, L; Van Calster, B; Lissoni, A A; Leone, F P G; Savelli, L; Franchi, D; Czekierdowski, A; Trio, D; Van Holsbeke, C; Ferrazzi, E; Scambia, G; Timmerman, D; Valentin, L

2012-09-01

To estimate the ability to discriminate between benign and malignant adnexal masses of different size using: subjective assessment, two International Ovarian Tumor Analysis (IOTA) logistic regression models (LR1 and LR2), the IOTA simple rules and the risk of malignancy index (RMI). We used a multicenter IOTA database of 2445 patients with at least one adnexal mass, i.e. the database previously used to prospectively validate the diagnostic performance of LR1 and LR2. The masses were categorized into three subgroups according to their largest diameter: small tumors (diameter < 4 cm; n = 396), medium-sized tumors (diameter, 4-9.9 cm; n = 1457) and large tumors (diameter ≥ 10 cm, n = 592). Subjective assessment, LR1 and LR2, IOTA simple rules and the RMI were applied to each of the three groups. Sensitivity, specificity, positive and negative likelihood ratio (LR+, LR-), diagnostic odds ratio (DOR) and area under the receiver-operating characteristics curve (AUC) were used to describe diagnostic performance. A moving window technique was applied to estimate the effect of tumor size as a continuous variable on the AUC. The reference standard was the histological diagnosis of the surgically removed adnexal mass. The frequency of invasive malignancy was 10% in small tumors, 19% in medium-sized tumors and 40% in large tumors; 11% of the large tumors were borderline tumors vs 3% and 4%, respectively, of the small and medium-sized tumors. The type of benign histology also differed among the three subgroups. For all methods, sensitivity with regard to malignancy was lowest in small tumors (56-84% vs 67-93% in medium-sized tumors and 74-95% in large tumors) while specificity was lowest in large tumors (60-87%vs 83-95% in medium-sized tumors and 83-96% in small tumors ). The DOR and the AUC value were highest in medium-sized tumors and the AUC was largest in tumors with a largest diameter of 7-11 cm. Tumor size affects the performance of subjective assessment, LR1 and LR2, the IOTA simple rules and the RMI in discriminating correctly between benign and malignant adnexal masses. The likely explanation, at least in part, is the difference in histology among tumors of different size. Copyright © 2012 ISUOG. Published by John Wiley & Sons, Ltd.

Autonomous identification of freezing of gait in Parkinson's disease from lower-body segmental accelerometry

PubMed Central

2013-01-01

Background We have previously published a technique for objective assessment of freezing of gait (FOG) in Parkinson's disease (PD) from a single shank-mounted accelerometer. Here we extend this approach to evaluate the optimal configuration of sensor placement and signal processing parameters using seven sensors attached to the lumbar back, thighs, shanks and feet. Methods Multi-segmental acceleration data was obtained from 25 PD patients performing 134 timed up and go tasks, and clinical assessment of FOG was performed by two experienced raters from video. Four metrics were used to compare objective and clinical measures; the intraclass correlation coefficient (ICC) for number of FOG episodes and the percent time frozen per trial; and the sensitivity and specificity of FOG detection. Results The seven-sensor configuration was the most robust, scoring highly on all measures of performance (ICC number of FOG 0.75; ICC percent time frozen 0.80; sensitivity 84.3%; specificity 78.4%). A simpler single-shank sensor approach provided similar ICC values and exhibited a high sensitivity to FOG events, but specificity was lower at 66.7%. Recordings from the lumbar sensor offered only moderate agreement with the clinical raters in terms of absolute number and duration of FOG events (likely due to musculoskeletal attenuation of lower-limb 'trembling' during FOG), but demonstrated a high sensitivity (86.2%) and specificity (82.4%) when considered as a binary test for the presence/absence of FOG within a single trial. Conclusions The seven-sensor approach was the most accurate method for quantifying FOG, and is best suited to demanding research applications. A single shank sensor provided measures comparable to the seven-sensor approach but is relatively straightforward in execution, facilitating clinical use. A single lumbar sensor may provide a simple means of objective FOG detection given the ubiquitous nature of accelerometers in mobile telephones and other belt-worn devices. PMID:23405951

Application of Recursive Partitioning to Derive and Validate a Claims-Based Algorithm for Identifying Keratinocyte Carcinoma (Nonmelanoma Skin Cancer).

PubMed

Chan, An-Wen; Fung, Kinwah; Tran, Jennifer M; Kitchen, Jessica; Austin, Peter C; Weinstock, Martin A; Rochon, Paula A

2016-10-01

Keratinocyte carcinoma (nonmelanoma skin cancer) accounts for substantial burden in terms of high incidence and health care costs but is excluded by most cancer registries in North America. Administrative health insurance claims databases offer an opportunity to identify these cancers using diagnosis and procedural codes submitted for reimbursement purposes. To apply recursive partitioning to derive and validate a claims-based algorithm for identifying keratinocyte carcinoma with high sensitivity and specificity. Retrospective study using population-based administrative databases linked to 602 371 pathology episodes from a community laboratory for adults residing in Ontario, Canada, from January 1, 1992, to December 31, 2009. The final analysis was completed in January 2016. We used recursive partitioning (classification trees) to derive an algorithm based on health insurance claims. The performance of the derived algorithm was compared with 5 prespecified algorithms and validated using an independent academic hospital clinic data set of 2082 patients seen in May and June 2011. Sensitivity, specificity, positive predictive value, and negative predictive value using the histopathological diagnosis as the criterion standard. We aimed to achieve maximal specificity, while maintaining greater than 80% sensitivity. Among 602 371 pathology episodes, 131 562 (21.8%) had a diagnosis of keratinocyte carcinoma. Our final derived algorithm outperformed the 5 simple prespecified algorithms and performed well in both community and hospital data sets in terms of sensitivity (82.6% and 84.9%, respectively), specificity (93.0% and 99.0%, respectively), positive predictive value (76.7% and 69.2%, respectively), and negative predictive value (95.0% and 99.6%, respectively). Algorithm performance did not vary substantially during the 18-year period. This algorithm offers a reliable mechanism for ascertaining keratinocyte carcinoma for epidemiological research in the absence of cancer registry data. Our findings also demonstrate the value of recursive partitioning in deriving valid claims-based algorithms.

The sensitivity and specificity of a urine based Rapid Diagnostic Test for the diagnosis of plasmodium falciparum in a malaria endemic area in Odisha, India.

PubMed

Samal, Ajit Gopal; Behera, Prativa Kumari; Mohanty, Akshay Kumar; Satpathi, Sanghamitra; Kumar, Abhishek; Panda, Rabi Ratna; Minz, Aruna Mukti; Mohanty, Sanjib; Samal, Abhijit; Van Der Pluijm, Rob W

2017-10-01

Rapid and accurate diagnosis is crucial in the treatment of malaria. Rapid Diagnostic Tests (RDTs) using blood have been recommended by the WHO as an acceptable method for the diagnosis of malaria. RDTs provide results quickly, is simple to use and easy to interpret. However, its use requires collection of blood by skin puncture. Hence the aim of the pilot study is to explore the sensitivity and specificity of RDTs using urine (collected non-invasively) for diagnosis of Plasmodium falciparum malaria and to assess the relation between parasite density in blood with HRP-2 Ag detection in urine. All fever cases admitted to Ispat General Hospital (IGH) Rourkela, India, during June 2012-March 2013 with a clinical diagnosis of malaria were examined for the presence of asexual forms of P. falciparum in peripheral blood smears. All smear positive febrile patients who met the eligibility criteria were enrolled. Smear negative fever cases were enrolled as control cases. RDTs were performed using both urine and blood samples by using commercially available blood specific kits. Sixty blood smear positive cases and 51 febrile blood smear negative cases were enrolled. Sensitivity and specificity of RDT urine were 86.67% (95%CI:75.83-93.09) and 94.12% (95%CI:84.08-97.98) respectively whereas those of RDT blood were 91.67% (95% CI: 81.93-96.39) and 98.04% (95% CI 89.7-99.65). The sensitivity of both RDT urine as well as RDT blood were found to be dependent on the level of parasitemia. Results of this study are promising. Larger studies are needed to assess whether RDTs using urine could serve as a practical, reliable method for the detection of P. falciparum in a non-invasive manner where invasive blood taking is less feasible.

Validity of Forced Eyelid Closure Test: A Novel Clinical Screening Test for Ocular Myasthenia Gravis.

PubMed

Apinyawasisuk, Supanut; Zhou, Xinkai; Tian, Jack J; Garcia, Giancarlo A; Karanjia, Rustum; Sadun, Alfredo A

2017-09-01

Forced eyelid closure test (FECT) is a clinical screening test developed from the original Cogan lid twitch (CLT) sign to assist in the diagnosis of ocular myasthenia gravis (OMG), We evaluated the sensitivity and specificity of FECT compared with CLT and benchmarked to standard diagnostic tests. This study was a retrospective chart review of 48 patients using electronic medical records of those that presented with ptosis and/or diplopia at Doheny Eye Institute, University of California, Los Angeles between February 2015 and April 2016. Patients without FECT testing were excluded. FECT and CLT results, and final diagnosis were recorded. To perform FECT, the patient was asked to squeeze his or her eyelids shut for 5-10 seconds then open quickly and fixate in primary position. The excessive upward overshoot of eyelids movement indicated a positive FECT. The test was performed by a neuro-ophthalmologist before establishing the diagnosis. Patients who had equivocal test results and/or inconclusive final diagnosis were excluded. Of the 48 patients studied, 18 patients (37.5%) had positive FECT; 15 of whom had a final diagnosis of OMG (83.3%). Of the 30 patients with negative FECT, 1 had OMG (3.3%). Of the 48 patients, 35 patients also had a documented CLT result (72.9%). CLT was positive in 11 of these 35 patients (31.4%), and 9 of these 11 had OMG (81.8%). Of the 24 patients with negative CLT, 2 of them had OMG (8.3%). Sensitivity and specificity of FECT were 94% and 91% (joint 95% confidence region: sensitivity × specificity = [0.70, 1] × [0.75, 1]). The relative true-positive fraction (rTPF) between FECT and CLT was 1.15; the relative false-positive fraction was 1.31. FECT is a simple clinical screening test with good sensitivity and specificity for OMG.

Efficient and Specific Detection of Salmonella in Food Samples Using a stn-Based Loop-Mediated Isothermal Amplification Method

PubMed Central

2015-01-01

The Salmonella enterotoxin (stn) gene exhibits high homology among S. enterica serovars and S. bongori. A set of 6 specific primers targeting the stn gene were designed for detection of Salmonella spp. using the loop-mediated isothermal amplification (LAMP) method. The primers amplified target sequences in all 102 strains of 87 serovars of Salmonella tested and no products were detected in 57 non-Salmonella strains. The detection limit in pure cultures was 5 fg DNA/reaction when amplified at 65°C for 25 min. The LAMP assay could detect Salmonella in artificially contaminated food samples as low as 220 cells/g of food without a preenrichment step. However, the sensitivity was increased 100-fold (~2 cells/g) following 5 hr preenrichment at 35°C. The LAMP technique, with a preenrichment step for 5 and 16 hr, was shown to give 100% specificity with food samples compared to the reference culture method in which 67 out of 90 food samples gave positive results. Different food matrixes did not interfere with LAMP detection which employed a simple boiling method for DNA template preparation. The results indicate that the LAMP method, targeting the stn gene, has great potential for detection of Salmonella in food samples with both high specificity and high sensitivity. PMID:26543859

A DNA Barcode-Based RPA Assay (BAR-RPA) for Rapid Identification of the Dry Root of Ficus hirta (Wuzhimaotao).

PubMed

Tian, Enwei; Liu, Qianqian; Ye, Haoting; Li, Fang; Chao, Zhi

2017-12-18

Background: Wuzhimaotao (the dry root of Ficus hirta ) is used as both medicine and food ingredient by the locals in areas around Nanling Mountains of China. Due to its very similar external morphologies with Duanchangcao (the root of Gelsemium elegans , which contains gelsemine that is extremely neurotoxic) and the associated growth of these two plants, incidents of food poisoning and even death frequently occur, resulting from the misuse of Duanchangcao as Wuzhimaotao. The aim of this study is to develop a fast, even, on-spot approach to identification of Wuzhimaotao. Methods: We used DNA barcode-based recombinase polymerase amplification (BAR-RPA) with species-specific primers targeting the internal transcribed spacer (ITS) region of the rDNA of F. hirta. BAR-RPA reaction time and temperature were optimized and the specificity and sensitivity of BAR-RPA species-specific primers were assessed. Results: This technique showed a high specificity and sensitivity to amplify the genomic DNA of F. hirta and allowed for rapid amplification (within 15 min) of the ITS region under a constant and mild temperature range of 37-42 °C without using thermocyclers. Conclusions: The BAR-RPA assay with a fast DNA extraction protocol provides a simple, energy-saving, and rapid method for identification of Wuzhimaotao in both laboratory and field settings.

Dynamics of microbial growth and metabolic activity and their control by aeration.

PubMed

Kalina, V

1993-01-01

The optimization of fermentation processes depends to a large extent on the modelling of microbial activity under complex environmental conditions where aeration is an important limiting and control factor. Simple relationships are used to establish the sensitivity of cultures to oxygen stress. Specific limitation coefficients which can be determined in laboratory reactors allow a projection to industrial operation and the definition of appropriate aeration and agitation profiles. Optimum control can be assured on the basis of directly measurable process parameters. This is shown for the case of ethanol production using S. cerevisiae at high cell dry weight concentrations.

Sub-millikelvin stabilization of a closed cycle cryocooler.

PubMed

Dubuis, Guy; He, Xi; Božović, Ivan

2014-10-01

Intrinsic temperature oscillations (with the amplitude up to 1 K) of a closed cycle cryocooler are stabilized by a simple thermal damping system. It employs three different materials with different thermal conductivity and specific heat at various temperatures. The amplitude of oscillations of the sample temperature is reduced to less than 1 mK, in the temperature range from 4 K to 300 K, while the cooling power is virtually undiminished. The damping system is small, inexpensive, can be retrofitted to most existing closed cycle cryocoolers, and may improve measurements of any temperature-sensitive physics properties.

Colorimetric Aptasensor Based on Enzyme for the Detection of Vibrio parahemolyticus.

PubMed

Wu, Shijia; Wang, Yinqiu; Duan, Nuo; Ma, Haile; Wang, Zhouping

2015-09-09

A simple colorimetric aptasensor system has been developed to detect Vibrio parahemolyticus. Magnetic nanoparticles (MNPs) are synthesized and conjugated with specific aptamers against target and used as capture probes. In addition, this method employs gold nanoparticles (AuNPs) as carriers of horseradish peroxidase (HRP) and aptamers, which served as signal probes. In the presence of target, a "sandwich-type" complex of AuNPs-HRP-aptamer-target-aptamer-MNPs is formed through specific recognition of aptamers and corresponding target. As a result, HRP molecules confined at the surface of the "sandwich" complexes catalyze the enzyme substrate, 3,3',5,5'-tetramethylbenzidine (TMB) and H2O2 and generate an optical signal. Under optimal conditions, the signals are linearly dependent on V. parahemolyticus concentrations from 10 to 10(6) colony-forming units (cfu)/mL in a logarithmic plot, with a limit of detection of 10 cfu/mL. Owing to AuNPs, a large amount of HRP could be loaded, resulting in an amplified signal, and the sensitivity would be improved. This strategy has the potential of being extended to the construction of simple monitor systems for a variety of biomolecules related to food safety.

Quantification of pathogen inactivation efficacy by free chlorine disinfection of drinking water for QMRA.

PubMed

Petterson, S R; Stenström, T A

2015-09-01

To support the implementation of quantitative microbial risk assessment (QMRA) for managing infectious risks associated with drinking water systems, a simple modeling approach for quantifying Log10 reduction across a free chlorine disinfection contactor was developed. The study was undertaken in three stages: firstly, review of the laboratory studies published in the literature; secondly, development of a conceptual approach to apply the laboratory studies to full-scale conditions; and finally implementation of the calculations for a hypothetical case study system. The developed model explicitly accounted for variability in residence time and pathogen specific chlorine sensitivity. Survival functions were constructed for a range of pathogens relying on the upper bound of the reported data transformed to a common metric. The application of the model within a hypothetical case study demonstrated the importance of accounting for variable residence time in QMRA. While the overall Log10 reduction may appear high, small parcels of water with short residence time can compromise the overall performance of the barrier. While theoretically simple, the approach presented is of great value for undertaking an initial assessment of a full-scale disinfection contactor based on limited site-specific information.

Simple and specific colorimetric detection of Staphylococcus using its volatile 2-[3-acetoxy-4,4,14-trimethylandrost-8-en-17-yl] propanoic acid in the liquid phase and head space of cultures.

PubMed

Saranya, Raju; Aarthi, Raju; Sankaran, Krishnan

2015-05-01

Spread of drug-resistant Staphylococcus spp. into communities pose danger demanding effective non-invasive and non-destructive tools for its early detection and surveillance. Characteristic volatile organic compounds (VOCs) produced by bacteria offer new diagnostic targets and novel approaches not exploited so far in infectious disease diagnostics. Our search for such characteristic VOC for Staphylococcus spp. led to the depiction of 2-[3-acetoxy-4,4,14-trimethylandrost-8-en-17-yl] propanoic acid (ATMAP), a moderately volatile compound detected both in the culture and headspace when the organism was grown in tryptone soya broth (TSB) medium. A simple and inexpensive colorimetric method (colour change from yellow to orange) using methyl red as the pH indicator provided an absolutely specific way for identifying Staphylococcus spp., The assay performed in liquid cultures (7-h growth in TSB) as well as in the headspace of plate cultures (grown for 10 h on TSA) was optimised in a 96-well plate and 12-well plate formats, respectively, employing a set of positive and negative strains. Only Staphylococcus spp. showed the distinct colour change from yellow to orange due to the production of the above VOC while in the case of other organisms, the reagent remained yellow. The method validated using known clinical and environmental strains (56 including Staphylococcus, Proteus, Pseudomonas, Klebsiella, Bacillus, Shigella and Escherichia coli) was found to be highly efficient showing 100% specificity and sensitivity. Such simple methods of bacterial pathogen identification are expected to form the next generation tools for the control of infectious diseases through early detection and surveillance of causative agents.

New Concepts of Fluorescent Probes for Specific Detection of DNA Sequences: Bis-Modified Oligonucleotides in Excimer and Exciplex Detection

PubMed Central

Gbaj, A; Bichenkova, EV; Walsh, L; Savage, HE; Sardarian, AR; Etchells, LL; Gulati, A; Hawisa, S; Douglas, KT

2009-01-01

The detection of single base mismatches in DNA is important for diagnostics, treatment of genetic diseases, and identification of single nucleotide polymorphisms. Highly sensitive, specific assays are needed to investigate genetic samples from patients. The use of a simple fluorescent nucleoside analogue in detection of DNA sequence and point mutations by hybridisation in solution is described in this study. The 5′-bispyrene and 3′-naphthalene oligonucleotide probes form an exciplex on hybridisation to target in water and the 5′-bispyrene oligonucleotide alone is an adequate probe to determine concentration of target present. It was also indicated that this system has a potential to identify mismatches and insertions. The aim of this work was to investigate experimental structures and conditions that permit strong exciplex emission for nucleic acid detectors, and show how such exciplexes can register the presence of mismatches as required in SNP analysis. This study revealed that the hybridisation of 5′-bispyrenyl fluorophore to a DNA target results in formation of a fluorescent probe with high signal intensity change and specificity for detecting a complementary target in a homogeneous system. Detection of SNP mutations using this split-probe system is a highly specific, simple, and accessible method to meet the rigorous requirements of pharmacogenomic studies. Thus, it is possible for the system to act as SNP detectors and it shows promise for future applications in genetic testing. PMID:21483539

Immunocytochemical detection of Mycobacterium Tuberculosis complex specific antigen, MPT64, improves diagnosis of tuberculous lymphadenitis and tuberculous pleuritis.

PubMed

Tadele, Agerie; Beyene, Demissew; Hussein, Jemal; Gemechu, Tuffa; Birhanu, Asaye; Mustafa, Tehmina; Tsegaye, Aster; Aseffa, Abraham; Sviland, Lisbet

2014-11-25

A rapid, sensitive and accurate laboratory diagnosis is of prime importance in suspected extrapulmonary tuberculosis (EPTB) cases. However, traditional techniques for the detection of acid-fast bacilli have limitations. The aim of the study was to evaluate the diagnostic value of immunocytochemical staining for detection of Mycobacterium tuberculosis complex specific antigen, MPT64, in aspirates from pleural effusions and lymph nodes, the most common presentations of EPTB. A cross-sectional study was conducted by including patients at Tikur Anbessa Specialized Hospital and the United Vision Medical Services from December 2011 to June 2012. Lymph node aspirates and pleural fluid samples were collected and analyzed from a total of 51 cases (26 tuberculous (TB) pleuritis and 25 TB lymphadenitis) and 67 non-TB controls. Each specimen was subjected to Ziehl-Neelsen (ZN) staining, culture on Lowenstein- Jensen (LJ) medium, cytological examination, Polymerase Chain Reaction (PCR) using IS1081gene sequence as a primer and immunocytochemistry (ICC) with polyclonal anti-MPT64 antibody. All patients were screened for HIV. ICC was positive in 38 of 51 cases and in the 7 of 67 controls giving an overall sensitivity and specificity of 74.5% and 89.5%, respectively. Using IS1081-PCR as a reference method, the sensitivity and specificity, positive and negative predictive value of ICC was 88.1%, 89.5%, 82.2% and 93.2%, respectively. The case detection rate increased from 13.7% by ZN stain to 19.6% by LJ culture, to 66.7% by cytology and 74.5% by ICC. Immunocytochemistry with anti-MPT64 antigen improved detection of TB in pleural effusion and lymph node aspirates. Further studies using monoclonal antibodies on samples from other sites of EPTB is recommended to validate this relatively simple diagnostic method for EPTB.

[Value of Immunohistochemical Methods in Detecting EML4-ALK Fusion Mutations: A Meta-analysis].

PubMed

Liu, Chang; Cai, Lu; Zhong, Diansheng; Wang, Jing

2016-01-01

The fusion between echinoderm microtubule-associated protein 4 (EML4) and anaplastic lymphatic tumor kinase (ALK) rearrangement is present in approximately 5% of non-small cell lung cancer (NSCLC) patients. It has been regarded as another new target gene after epidermal growth factor receptor (EGFR) and K-ras. Figures showed that the disease control rate could reach up to 80% in NSCLC patients with EML4-ALK fusion gene after treated with ALK inhibitors. Thus, exploring an accurate and rapid detecting method is the key in screening NSCLC patients with EML4-ALK expressions. The aim of this study is to analyze the specificity and sensitivity of IHC in detecting EML4-ALK fusion mutations. To evaluate the accuracy and clinical value of this method, and then provide basis for individual molecular therapy of NSCLC patients. Using Pubmed database to search all documents required. The deadline of retrieval was February 25, 2015. Then further screening the articles according to the inclusion and exclusion criteria. Using diagnostic test meta-analysis methods to analyze the sensitivity and specificity of the immunohistochemistry (IHC) method compared with fluorescence in situ hybridization (FISH) method. Eleven literatures were added into the meta analysis, there were 3,234 of total cases. The diagnostic odds ratio (DOR) was 1,135.00 (95%CI: 337.10-3,821.46); the area under curve (AUC) of summary receiver operating characteristic curve (SROC) curve was 0.992,3 (SEAUC=0.003,2), the Q* was 0.964,4 (SEQ*=0.008,7). Immunohistochemical detection of EML4-ALK fusion gene mutation with specific antibody is feasible. It has high sensitivity and specificity. IHC can be a simple and rapid way in screening EML4-ALK fusion gene mutation and exhibits important clinical values.

Ottawa Ankle Rules and Subjective Surgeon Perception to Evaluate Radiograph Necessity Following Foot and Ankle Sprain

PubMed Central

Pires, RES; Pereira, AA; Abreu-e-Silva, GM; Labronici, PJ; Figueiredo, LB; Godoy-Santos, AL; Kfuri, M

2014-01-01

Background: Foot and ankle injuries are frequent in emergency departments. Although only a few patients with foot and ankle sprain present fractures and the fracture patterns are almost always simple, lack of fracture diagnosis can lead to poor functional outcomes. Aim: The present study aims to evaluate the reliability of the Ottawa ankle rules and the orthopedic surgeon subjective perception to assess foot and ankle fractures after sprains. Subjects and Methods: A cross-sectional study was conducted from July 2012 to December 2012. Ethical approval was granted. Two hundred seventy-four adult patients admitted to the emergency department with foot and/or ankle sprain were evaluated by an orthopedic surgeon who completed a questionnaire prior to radiographic assessment. The Ottawa ankle rules and subjective perception of foot and/or ankle fractures were evaluated on the questionnaire. Results: Thirteen percent (36/274) patients presented fracture. Orthopedic surgeon subjective analysis showed 55.6% sensitivity, 90.1% specificity, 46.5% positive predictive value and 92.9% negative predictive value. The general orthopedic surgeon opinion accuracy was 85.4%. The Ottawa ankle rules presented 97.2% sensitivity, 7.8% specificity, 13.9% positive predictive value, 95% negative predictive value and 19.9% accuracy respectively. Weight-bearing inability was the Ottawa ankle rule item that presented the highest reliability, 69.4% sensitivity, 61.6% specificity, 63.1% accuracy, 21.9% positive predictive value and 93% negative predictive value respectively. Conclusion: The Ottawa ankle rules showed high reliability for deciding when to take radiographs in foot and/or ankle sprains. Weight-bearing inability was the most important isolated item to predict fracture presence. Orthopedic surgeon subjective analysis to predict fracture possibility showed a high specificity rate, representing a confident method to exclude unnecessary radiographic exams. PMID:24971221

Development of a Simple, Peripheral-Blood-Based Lateral-Flow Dipstick Assay for Accurate Detection of Patients with Enteric Fever

PubMed Central

Khan, Iqbal Hassan; Sayeed, M. Abu; Sultana, Nishat; Islam, Kamrul; Amin, Jakia; Faruk, M. Omar; Khan, Umama; Khanam, Farhana; Ryan, Edward T.

2016-01-01

Enteric fever is a systemic infection caused by typhoidal strains of Salmonella enterica and is a significant cause of mortality and morbidity in many parts of the world, especially in resource-limited areas. Unfortunately, currently available diagnostic tests for enteric fever lack sensitivity and/or specificity. No true clinically practical gold standard for diagnosing patients with enteric fever exists. Unfortunately, microbiologic culturing of blood is only 30 to 70% sensitive although 100% specific. Here, we report the development of a lateral-flow immunochromatographic dipstick assay based on the detection of Salmonella enterica serovar Typhi (S. Typhi) lipopolysaccharide (LPS)-specific IgG in lymphocyte culture secretion. We tested the assay using samples from 142 clinically suspected enteric fever patients, 28 healthy individuals residing in a zone where enteric fever is endemic, and 35 patients with other febrile illnesses. In our analysis, the dipstick detected all blood culture-confirmed S. Typhi cases (48/48) and 5 of 6 Salmonella enterica serovar Paratyphi A blood cultured-confirmed cases. The test was negative in all 35 individuals febrile with other illnesses and all 28 healthy controls from the zone of endemicity. The test was positive in 19 of 88 individuals with suspected enteric fever but with negative blood cultures. Thus, the dipstick had a sensitivity of 98% compared to blood culture results and a specificity that ranged from 78 to 100% (95% confidence interval [CI], 70 to 100%), depending on the definition of a true negative. These results suggest that this dipstick assay can be very useful for the detection of enteric fever patients especially in regions of endemicity. PMID:26961857

Development of a single-antigen magnetic bead assay (SAMBA) for the sensitive detection of HPA-1a alloantibodies using tag-engineered recombinant soluble β3 integrin.

PubMed

Skaik, Younis; Battermann, Anja; Hiller, Oliver; Meyer, Oliver; Figueiredo, Constanca; Salama, Abdulgabar; Blasczyk, Rainer

2013-05-31

Timely and accurate testing for human platelet antigen 1a (HPA-1a) alloantibodies is vital for clinical diagnosis of neonatal alloimmune thrombocytopenia (NAIT). Current antigen-specific assays used for the detection of HPA-1 alloantibodies are technically very complex and cumbersome for most diagnostic laboratories. Hence, we designed and applied recombinant soluble (rs) β3 integrins displaying HPA-1a or HPA-1b epitopes for the development of a single-antigen magnetic bead assay (SAMBA). Soluble HPA-1a and HPA-1b were produced recombinantly in human embryonic kidney 293 (HEK293) cells and differentially tagged. The recombinant soluble proteins were then immobilized onto paramagnetic beads and used for analysis of HPA-1 alloantibodies by enzyme-linked immunosorbent assay (ELISA). HPA-1a serum samples (n=7) from NAIT patients, inert sera and sera containing non-HPA-1a antibodies were used to evaluate the sensitivity and specificity of the SAMBA. Fusion of V5-His or GS-SBP-His tags to the rsβ3 integrins resulted in high-yield expression. SAMBA was able to detect all HPA-1a and -1b alloantibodies recognized by monoclonal antibody-specific immobilization of platelet antigens assay (MAIPA). No cross-reactions between the sera were observed. Two out of seven of the HPA-1a alloantibody-containing sera demonstrated weak to moderate reactivity in MAIPA but strong signals in SAMBA. SAMBA provides a very reliable method for the detection of HPA-1 antibodies with high specificity and sensitivity. This simple and rapid assay can be adapted for use in any routine laboratory and can be potentially adapted for use on automated systems. Copyright © 2013 Elsevier B.V. All rights reserved.

Neuropad for the detection of cardiovascular autonomic neuropathy in patients with type 2 diabetes.

PubMed

Mendivil, Carlos O; Kattah, William; Orduz, Arturo; Tique, Claudia; Cárdenas, José L; Patiño, Jorge E

2016-01-01

Cardiovascular autonomic neuropathy (CAN) is a prevalent and neglected chronic complication of diabetes, with a large impact on morbidity and mortality. Part of the reason why it is not detected and treated opportunely is because of the complexity of the tests required for its diagnosis. We evaluated the Neuropad®, a test based on sudomotor function, as a screening tool for CAN in adult patients with type 2 diabetes in Bogotá, Colombia. This was a cross-sectional evaluation of Neuropad® for the detection of CAN. Patients were 20-75years of age and did not suffer from any other type of neuropathy. CAN was diagnosed using the Ewing battery of tests for R-R variability during deep breathing, Valsalva and lying-to-standing maneuvers. Additionally, distal symmetric polyneuropathy (DSP) was diagnosed using a sign-based scale (Michigan Neuropathy Disability Score - NDS) and a symptom-based score (Total Symptom Score - TSS). The primary outcome was the sensitivity and specificity of the Neuropad® for the diagnosis of CAN, and secondary outcomes were the sensitivity and specificity of Neuropad® for DSP. We studied 154 patients (74 men and 80 women). Prevalence of CAN was extremely high (68.0% of study participants), but also DSP was prevalent, particularly according to the signs-based definition (45%). The sensitivity of the Neuropad® for any degree of CAN was 70.1%, being slightly higher for the deep breathing and Valsalva tests than for lying-to-standing. The specificity of the Neuropad® for any type of CAN was only 37.0%, as expected for a screening exam. The negative predictive value was higher for the deep breathing and Valsalva tests (69.4 and 81.6%, respectively). Neuropad showed also a good sensitivity and negative predictive value for DSP. The sensitivity and specificity of Neuropad were better among men, and among patients with diabetes duration above the group median. The Neuropad is a simple and inexpensive device that demonstrated an adequate performance as a screening tool for cardiovascular autonomic neuropathy in Latin American patients with DM2. Copyright © 2016 Elsevier Inc. All rights reserved.

Reliability of fluorescein dye disappearance test in assessment of adults with nasolacrimal duct obstruction.

PubMed

Kashkouli, Mohsen Bahmani; Mirzajani, Hoora; Jamshidian-Tehrani, Mansooreh; Pakdel, Farzad; Nojomi, Marzieh; Aghaei, Gholam-Hossein

2013-01-01

To evaluate the role of fluorescein dye disappearance test (FDDT) in assessment of adults with primary acquired nasolacrimal duct obstruction (PANDO) and its correlation with age and severity of epiphora. In a prospective, cross-sectional comparative study, FDDT at 2 (2-FDDT), 5 (5-FDDT), and 10 (10-FDDT) minutes were performed in 58 eyes of 58 patients with PANDO (case) and 58 eyes of 58 subjects without epiphora (control) between 2008 and 2010. Exclusion criteria were any disease, trauma, or medications that might have an effect on tear drainage system. Patients with functional or incomplete obstruction and upper lacrimal drainage system obstruction were excluded in the case group. FDDT and severity of epiphora were graded. Case and control groups were matched. 2-FDDT showed a sensitivity of 82.8%, specificity of 91.4%, positive predictive value of 90.6%, and negative predictive value of 84.1%. Sensitivity and negative predictive value decreased to 71.1% and 78.6% in 5-FDDT. 5-FDDT specificity and positive predictive value, however, increased to 94.8% and 93.5%, respectively. There was no statistically significant correlation between severity of epiphora and age with FDDT. FDDT is a simple, reliable, and highly specific test in assessment of adults with PANDO.

Polythiophene nanofilms for sensitive fluorescence detection of viruses in drinking water.

PubMed

Wankar, Shashwati; Turner, Nicholas W; Krupadam, Reddithota J

2016-08-15

Molecular imprints of the tobacco necrosis virus (TNV) have been formed within polythiophene nanofilms with an approximate thickness of 200nm. These films have been electrochemically deposited onto conducting Au surfaces. Upon rebinding, the TNV-polythiophene complex changes the fluorescence intensity of the nanofilm. The fluorescence intensity at 410nm was observed to be proportional to the concentration of viruses in the range of 0.1-10ngL(-1) (0.15-15pg) with the lower calculated detection limit of 2.29ngL(-1) (3.4pg). The intensity of the fluorescence emission is not affected by the thickness of the polythiophene film and the nature of TNV specific binding sites. Kinetic data analyses showed that the nanofilm responds to TNV within 2min; and cross-selectivity studies with tobacco mosaic virus (TMV) showed an excellent specificity for the targeted TNV. These binding experiments demonstrate the potential of fluorescence emission for the specific, label free and rapid detection of viruses using nanofilm sensors. Taking into account the lower limit of detection, the fluorescence sensing reported here is reliable, simple to perform, rapid, cost-effective and offers a sensitive analytical method for virus detection in water resources. Copyright © 2016 Elsevier B.V. All rights reserved.

Aptamer-Based Dual-Functional Probe for Rapid and Specific Counting and Imaging of MCF-7 Cells.

PubMed

Yang, Bin; Chen, Beibei; He, Man; Yin, Xiao; Xu, Chi; Hu, Bin

2018-02-06

Development of multimodal detection technologies for accurate diagnosis of cancer at early stages is in great demand. In this work, we report a novel approach using an aptamer-based dual-functional probe for rapid, sensitive, and specific counting and visualization of MCF-7 cells by inductively coupled plasma-mass spectrometry (ICP-MS) and fluorescence imaging. The probe consists of a recognition unit of aptamer to catch cancer cells specifically, a fluorescent dye (FAM) moiety for fluorescence resonance energy transfer (FRET)-based "off-on" fluorescence imaging as well as gold nanoparticles (Au NPs) tag for both ICP-MS quantification and fluorescence quenching. Due to the signal amplification effect and low spectral interference of Au NPs in ICP-MS, an excellent linearity and sensitivity were achieved. Accordingly, a limit of detection of 81 MCF-7 cells and a relative standard deviation of 5.6% (800 cells, n = 7) were obtained. The dynamic linear range was 2 × 10 2 to 1.2 × 10 4 cells, and the recoveries in human whole blood were in the range of 98-110%. Overall, the established method provides quantitative and visualized information on MCF-7 cells with a simple and rapid process and paves the way for a promising strategy for biomedical research and clinical diagnostics.

Cumulative exposure to work-related traumatic events and current post-traumatic stress disorder in New York City's first responders.

PubMed

Geronazzo-Alman, Lupo; Eisenberg, Ruth; Shen, Sa; Duarte, Cristiane S; Musa, George J; Wicks, Judith; Fan, Bin; Doan, Thao; Guffanti, Guia; Bresnahan, Michaeline; Hoven, Christina W

2017-04-01

Cumulative exposure to work-related traumatic events (CE) is a foreseeable risk for psychiatric disorders in first responders (FRs). Our objective was to examine the impact of work-related CE that could serve as predictor of posttraumatic stress disorder (PTSD) and/or depression in FRs. Cross-sectional examination of previous CE and past-month PTSD outcomes and depression in 209 FRs. Logistic (probable PTSD; probable depression) and Poisson regressions (PTSD score) of the outcomes on work-related CE indexes, adjusting for demographic variables. Differences across occupational groups were also examined. Receiver operating characteristic analysis determined the sensitivity and specificity of CE indexes. All indexes were significantly and differently associated with PTSD; associations with depression were non-significant. The index capturing the sheer number of different incidents experienced regardless of frequency ('Variety') showed conceptual, practical and statistical advantages compared to other indexes. In general, the indexes showed poor to fair discrimination accuracy. Work-related CE is specifically associated with PTSD. Focusing on the variety of exposures may be a simple and effective strategy to predict PTSD in FRs. Further research on sensitivity and specificity of exposure indexes, preferably examined prospectively, is needed and could lead to early identification of individuals at risk. Copyright © 2016 Elsevier Inc. All rights reserved.

Rapid, whole blood diagnostic test for detecting anti-hantavirus antibody in rats.

PubMed

Amada, Takako; Yoshimatsu, Kumiko; Yasuda, Shumpei P; Shimizu, Kenta; Koma, Takaaki; Hayashimoto, Nobuhito; Gamage, Chandika D; Nishio, Sanae; Takakura, Akira; Arikawa, Jiro

2013-10-01

Hantavirus is a causative agent of rodent-borne viral zoonoses, hemorrhagic fever with renal syndrome (HFRS) and hantavirus pulmonary syndrome. Seoul virus (SEOV) is a causative agent of urban and laboratory rat-associated HFRS worldwide. Surveillance of rodents has been done mainly by serological detection of hantavirus-specific antibodies by enzyme linked immunosorbent assay (ELISA) and immunofluorescent antibody assay (IFA). An immunochromatographic (ICG) test was developed with the N-terminal 103 amino acids of nucleocapsid protein of Hantaan virus expressed by Escherichia coli as an antigen to detect IgG antibody specific to hantavirus in sera from Rattus sp. animals. Antibody-detecting sensitivity of the ICG test was the same as that of ELISA and about 100-times higher than that of IFA. Overall sensitivities and specificities of the ICG test in comparison to ELISA and IFA for sera from 192 urban rats and 123 laboratory rats were 99.3% and 100%, respectively. Diluted whole blood samples without separation could be used for the ICG test. The ICG test enabled detection of antibodies to SEOV, Hantaan, Dobrava/Belgrade, and Thailand viruses, which are causative agents of HFRS throughout Eurasia. The ICG test is a rapid, simple and safe method for diagnosis of SEOV infection in rats. Copyright © 2013 Elsevier B.V. All rights reserved.

Measuring spatial and temporal Ca2+ signals in Arabidopsis plants.

PubMed

Zhu, Xiaohong; Taylor, Aaron; Zhang, Shenyu; Zhang, Dayong; Feng, Ying; Liang, Gaimei; Zhu, Jian-Kang

2014-09-02

Developmental and environmental cues induce Ca(2+) fluctuations in plant cells. Stimulus-specific spatial-temporal Ca(2+) patterns are sensed by cellular Ca(2+) binding proteins that initiate Ca(2+) signaling cascades. However, we still know little about how stimulus specific Ca(2+) signals are generated. The specificity of a Ca(2+) signal may be attributed to the sophisticated regulation of the activities of Ca(2+) channels and/or transporters in response to a given stimulus. To identify these cellular components and understand their functions, it is crucial to use systems that allow a sensitive and robust recording of Ca(2+) signals at both the tissue and cellular levels. Genetically encoded Ca(2+) indicators that are targeted to different cellular compartments have provided a platform for live cell confocal imaging of cellular Ca(2+) signals. Here we describe instructions for the use of two Ca(2+) detection systems: aequorin based FAS (film adhesive seedlings) luminescence Ca(2+) imaging and case12 based live cell confocal fluorescence Ca(2+) imaging. Luminescence imaging using the FAS system provides a simple, robust and sensitive detection of spatial and temporal Ca(2+) signals at the tissue level, while live cell confocal imaging using Case12 provides simultaneous detection of cytosolic and nuclear Ca(2+) signals at a high resolution.

Endpoint visual detection of three genetically modified rice events by loop-mediated isothermal amplification.

PubMed

Chen, Xiaoyun; Wang, Xiaofu; Jin, Nuo; Zhou, Yu; Huang, Sainan; Miao, Qingmei; Zhu, Qing; Xu, Junfeng

2012-11-07

Genetically modified (GM) rice KMD1, TT51-1, and KF6 are three of the most well known transgenic Bt rice lines in China. A rapid and sensitive molecular assay for risk assessment of GM rice is needed. Polymerase chain reaction (PCR), currently the most common method for detecting genetically modified organisms, requires temperature cycling and relatively complex procedures. Here we developed a visual and rapid loop-mediated isothermal amplification (LAMP) method to amplify three GM rice event-specific junction sequences. Target DNA was amplified and visualized by two indicators (SYBR green or hydroxy naphthol blue [HNB]) within 60 min at an isothermal temperature of 63 °C. Different kinds of plants were selected to ensure the specificity of detection and the results of the non-target samples were negative, indicating that the primer sets for the three GM rice varieties had good levels of specificity. The sensitivity of LAMP, with detection limits at low concentration levels (0.01%−0.005% GM), was 10- to 100-fold greater than that of conventional PCR. Additionally, the LAMP assay coupled with an indicator (SYBR green or HNB) facilitated analysis. These findings revealed that the rapid detection method was suitable as a simple field-based test to determine the status of GM crops.

Performance of blend sign in predicting hematoma expansion in intracerebral hemorrhage: A meta-analysis.

PubMed

Yu, Zhiyuan; Zheng, Jun; Guo, Rui; Ma, Lu; Li, Mou; Wang, Xiaoze; Lin, Sen; Li, Hao; You, Chao

2017-12-01

Hematoma expansion is independently associated with poor outcome in intracerebral hemorrhage (ICH). Blend sign is a simple predictor for hematoma expansion on non-contrast computed tomography. However, its accuracy for predicting hematoma expansion is inconsistent in previous studies. This meta-analysis is aimed to systematically assess the performance of blend sign in predicting hematoma expansion in ICH. A systematic literature search was conducted. Original studies about predictive accuracy of blend sign for hematoma expansion in ICH were included. Pooled sensitivity, specificity, positive and negative likelihood ratios were calculated. Summary receiver operating characteristics curve was constructed. Publication bias was assessed by Deeks' funnel plot asymmetry test. A total of 5 studies with 2248 patients were included in this meta-analysis. The pooled sensitivity, specificity, positive and negative likelihood ratios of blend sign for predicting hematoma expansion were 0.28, 0.92, 3.4 and 0.78, respectively. The area under the curve (AUC) was 0.85. No significant publication bias was found. This meta-analysis demonstrates that blend sign is a useful predictor with high specificity for hematoma expansion in ICH. Further studies with larger sample size are still necessary to verify the accuracy of blend sign for predicting hematoma expansion. Copyright © 2017 Elsevier B.V. All rights reserved.

The Hand Burn Severity (HABS) score: A simple tool for stratifying severity of hand burns.

PubMed

Bache, Sarah E; Fitzgerald O'Connor, Edmund; Theodorakopoulou, Evgenia; Frew, Quentin; Philp, Bruce; Dziewulski, Peter

2017-02-01

Hand burns represent a unique challenge to the burns team due to the intricate structure and unrivalled functional importance of the hand. The initial assessment and prognosis relies on consideration of the specific site involved as well as depth of the burn. We created a simple severity score that could be used by referring non-specialists and researchers alike. The Hand Burn Severity (HABS) score stratifies hand burns according to severity with a numerical value of between 0 (no burn) and 18 (most severe) per hand. Three independent assessors scored the photographs of 121 burned hands of 106 adult and paediatric patients, demonstrating excellent inter-rater reliability (r=0.91, p<0.0001 on testing with Lin's correlation coefficient). A significant relationship was shown between the HABS score and a reliable binary outcome of the requirement for surgical excision on Mann-Whitney U testing (U=152; Z=9.8; p=0.0001). A receiver operator characteristic (ROC) curve analysis found a cut off score of 5.5, indicating that those with a HABS score below 6 did not require an operation, whereas those with a score above 6 did. The HABS score was shown to be more sensitive and specific that assessment of burn depth alone. The HABS score is a simple to use tool to stratify severity at initial presentation of hand burns which will be useful when referring, and when reporting outcomes. Copyright © 2016 Elsevier Ltd and ISBI. All rights reserved.

Rapid detection of aflatoxigenic Aspergillus sp. in herbal specimens by a simple, bendable, paper-based lab-on-a-chip.

PubMed

Chaumpluk, Piyasak; Plubcharoensook, Pattra; Prasongsuk, Sehanat

2016-06-01

Postharvest herbal product contamination with mycotoxins and mycotoxin-producing fungi represents a potentially carcinogenic hazard. Aspergillus flavus is a major cause of this issue. Available mold detection methods are PCR-based and rely heavily on laboratories; thus, they are unsuitable for on-site monitoring. In this study, a bendable, paper-based lab-on-a-chip platform was developed to rapidly detect toxigenic Aspergillus spp. DNA. The 3.0-4.0 cm(2) chip is fabricated using Whatman™ filter paper, fishing line and a simple plastic lamination process and has nucleic acid amplification and signal detection components. The Aspergillus assay specifically amplifies the aflatoxin biosynthesis gene, aflR, using loop-mediated isothermal amplification (LAMP); hybridization between target DNA and probes on blue silvernanoplates (AgNPls) yields colorimetric results. Positive results are indicated by the detection pad appearing blue due to dispersed blue AgNPls; negative results are indicated by the detection pad appearing colorless or pale yellow due to probe/target DNA hybridization and AgNPls aggregation. Assay completion requires less than 40 min, has a limit of detection (LOD) of 100 aflR copies, and has high specificity (94.47%)and sensitivity (100%). Contamination was identified in 14 of 32 herbal samples tested (43.75%). This work demonstrates the fabrication of a simple, low-cost, paper-based lab-on-a-chip platform suitable for rapid-detection applications. Copyright © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

In vivo neuronal calcium imaging in C. elegans.

PubMed

Chung, Samuel H; Sun, Lin; Gabel, Christopher V

2013-04-10

The nematode worm C. elegans is an ideal model organism for relatively simple, low cost neuronal imaging in vivo. Its small transparent body and simple, well-characterized nervous system allows identification and fluorescence imaging of any neuron within the intact animal. Simple immobilization techniques with minimal impact on the animal's physiology allow extended time-lapse imaging. The development of genetically-encoded calcium sensitive fluorophores such as cameleon and GCaMP allow in vivo imaging of neuronal calcium relating both cell physiology and neuronal activity. Numerous transgenic strains expressing these fluorophores in specific neurons are readily available or can be constructed using well-established techniques. Here, we describe detailed procedures for measuring calcium dynamics within a single neuron in vivo using both GCaMP and cameleon. We discuss advantages and disadvantages of both as well as various methods of sample preparation (animal immobilization) and image analysis. Finally, we present results from two experiments: 1) Using GCaMP to measure the sensory response of a specific neuron to an external electrical field and 2) Using cameleon to measure the physiological calcium response of a neuron to traumatic laser damage. Calcium imaging techniques such as these are used extensively in C. elegans and have been extended to measurements in freely moving animals, multiple neurons simultaneously and comparison across genetic backgrounds. C. elegans presents a robust and flexible system for in vivo neuronal imaging with advantages over other model systems in technical simplicity and cost.

Peregrine: A rapid and unbiased method to produce strand-specific RNA-Seq libraries from small quantities of starting material.

PubMed

Langevin, Stanley A; Bent, Zachary W; Solberg, Owen D; Curtis, Deanna J; Lane, Pamela D; Williams, Kelly P; Schoeniger, Joseph S; Sinha, Anupama; Lane, Todd W; Branda, Steven S

2013-04-01

Use of second generation sequencing (SGS) technologies for transcriptional profiling (RNA-Seq) has revolutionized transcriptomics, enabling measurement of RNA abundances with unprecedented specificity and sensitivity and the discovery of novel RNA species. Preparation of RNA-Seq libraries requires conversion of the RNA starting material into cDNA flanked by platform-specific adaptor sequences. Each of the published methods and commercial kits currently available for RNA-Seq library preparation suffers from at least one major drawback, including long processing times, large starting material requirements, uneven coverage, loss of strand information and high cost. We report the development of a new RNA-Seq library preparation technique that produces representative, strand-specific RNA-Seq libraries from small amounts of starting material in a fast, simple and cost-effective manner. Additionally, we have developed a new quantitative PCR-based assay for precisely determining the number of PCR cycles to perform for optimal enrichment of the final library, a key step in all SGS library preparation workflows.

Treatment Default amongst Patients with Tuberculosis in Urban Morocco: Predicting and Explaining Default and Post-Default Sputum Smear and Drug Susceptibility Results

PubMed Central

Ghali, Iraqi; Kizub, Darya; Billioux, Alexander C.; Bennani, Kenza; Bourkadi, Jamal Eddine; Benmamoun, Abderrahmane; Lahlou, Ouafae; Aouad, Rajae El; Dooley, Kelly E.

2014-01-01

Setting Public tuberculosis (TB) clinics in urban Morocco. Objective Explore risk factors for TB treatment default and develop a prediction tool. Assess consequences of default, specifically risk for transmission or development of drug resistance. Design Case-control study comparing patients who defaulted from TB treatment and patients who completed it using quantitative methods and open-ended questions. Results were interpreted in light of health professionals’ perspectives from a parallel study. A predictive model and simple tool to identify patients at high risk of default were developed. Sputum from cases with pulmonary TB was collected for smear and drug susceptibility testing. Results 91 cases and 186 controls enrolled. Independent risk factors for default included current smoking, retreatment, work interference with adherence, daily directly observed therapy, side effects, quick symptom resolution, and not knowing one’s treatment duration. Age >50 years, never smoking, and having friends who knew one’s diagnosis were protective. A simple scoring tool incorporating these factors was 82.4% sensitive and 87.6% specific for predicting default in this population. Clinicians and patients described additional contributors to default and suggested locally-relevant intervention targets. Among 89 cases with pulmonary TB, 71% had sputum that was smear positive for TB. Drug resistance was rare. Conclusion The causes of default from TB treatment were explored through synthesis of qualitative and quantitative data from patients and health professionals. A scoring tool with high sensitivity and specificity to predict default was developed. Prospective evaluation of this tool coupled with targeted interventions based on our findings is warranted. Of note, the risk of TB transmission from patients who default treatment to others is likely to be high. The commonly-feared risk of drug resistance, though, may be low; a larger study is required to confirm these findings. PMID:24699682

Use of elastin fibre detection in the diagnosis of ventilator associated pneumonia.

PubMed

el-Ebiary, M; Torres, A; González, J; Martos, A; Puig de la Bellacasa, J; Ferrer, M; Rodriguez-Roisin, R

1995-01-01

Elastin fibre detection could be a simple and reliable marker of ventilator associated pneumonia. To confirm this, a prospective study was undertaken to evaluate the diagnostic yield of elastin fibre detection in the diagnosis of ventilator associated pneumonia. Seventy eight mechanically ventilated patients were evaluated by examining endotracheal aspirates for the presence of elastin fibres. All patients were previously treated with antibiotics. Quantitative bacterial cultures of endotracheal aspirates and protected specimen brush samples were also performed. Patients were classified into three diagnostic categories: group 1, definite pneumonia (n = 25); group 2, probable pneumonia (n = 35); and group 3, controls (n = 18). Patients with definite and probable pneumonia were grouped together. The presence of elastin fibres in endotracheal aspirate samples was more frequent in groups 1 and 2, being found in 19 of the 60 patients compared with five of the control group. Although the presence of elastin fibres had a low sensitivity (32%), it was a reasonably specific marker (72%) of pneumonia. This specificity increased to 86% and 81% respectively when only Gram negative bacilli and Pseudomonas aeruginosa pneumonia were considered. Again, calculated sensitivity was 43% and 44% when analysing cases infected by Gram negative bacilli and Ps aeruginosa, respectively. The negative predictive value of the detection of elastin fibres in pneumonia caused by Ps aeruginosa was 81%. Detection was more frequent with infection by Gram negative bacilli (14/19), particularly with Ps aeruginosa (8/14). By contrast, pneumonia due to Gram positive cocci or non-bacterial agents uncommonly resulted in positive elastin fibre preparations (4/19, 21%). When analysing patients with and without chronic obstructive pulmonary disease, the diagnostic value of elastin fibre detection did not change. Potassium hydroxide preparation of elastin fibres is a rapid and simple specific marker of ventilator associated pneumonia and may be a useful technique to help diagnose pulmonary infections in mechanically ventilated patients, although this assessment is at present limited to patients without adult respiratory distress syndrome.

Use of elastin fibre detection in the diagnosis of ventilator associated pneumonia.

PubMed Central

el-Ebiary, M.; Torres, A.; González, J.; Martos, A.; Puig de la Bellacasa, J.; Ferrer, M.; Rodriguez-Roisin, R.

1995-01-01

BACKGROUND--Elastin fibre detection could be a simple and reliable marker of ventilator associated pneumonia. To confirm this, a prospective study was undertaken to evaluate the diagnostic yield of elastin fibre detection in the diagnosis of ventilator associated pneumonia. METHODS--Seventy eight mechanically ventilated patients were evaluated by examining endotracheal aspirates for the presence of elastin fibres. All patients were previously treated with antibiotics. Quantitative bacterial cultures of endotracheal aspirates and protected specimen brush samples were also performed. Patients were classified into three diagnostic categories: group 1, definite pneumonia (n = 25); group 2, probable pneumonia (n = 35); and group 3, controls (n = 18). RESULTS--Patients with definite and probable pneumonia were grouped together. The presence of elastin fibres in endotracheal aspirate samples was more frequent in groups 1 and 2, being found in 19 of the 60 patients compared with five of the control group. Although the presence of elastin fibres had a low sensitivity (32%), it was a reasonably specific marker (72%) of pneumonia. This specificity increased to 86% and 81% respectively when only Gram negative bacilli and Pseudomonas aeruginosa pneumonia were considered. Again, calculated sensitivity was 43% and 44% when analysing cases infected by Gram negative bacilli and Ps aeruginosa, respectively. The negative predictive value of the detection of elastin fibres in pneumonia caused by Ps aeruginosa was 81%. Detection was more frequent with infection by Gram negative bacilli (14/19), particularly with Ps aeruginosa (8/14). By contrast, pneumonia due to Gram positive cocci or non-bacterial agents uncommonly resulted in positive elastin fibre preparations (4/19, 21%). When analysing patients with and without chronic obstructive pulmonary disease, the diagnostic value of elastin fibre detection did not change. CONCLUSIONS--Potassium hydroxide preparation of elastin fibres is a rapid and simple specific marker of ventilator associated pneumonia and may be a useful technique to help diagnose pulmonary infections in mechanically ventilated patients, although this assessment is at present limited to patients without adult respiratory distress syndrome. PMID:7886642

Database searching and accounting of multiplexed precursor and product ion spectra from the data independent analysis of simple and complex peptide mixtures.

PubMed

Li, Guo-Zhong; Vissers, Johannes P C; Silva, Jeffrey C; Golick, Dan; Gorenstein, Marc V; Geromanos, Scott J

2009-03-01

A novel database search algorithm is presented for the qualitative identification of proteins over a wide dynamic range, both in simple and complex biological samples. The algorithm has been designed for the analysis of data originating from data independent acquisitions, whereby multiple precursor ions are fragmented simultaneously. Measurements used by the algorithm include retention time, ion intensities, charge state, and accurate masses on both precursor and product ions from LC-MS data. The search algorithm uses an iterative process whereby each iteration incrementally increases the selectivity, specificity, and sensitivity of the overall strategy. Increased specificity is obtained by utilizing a subset database search approach, whereby for each subsequent stage of the search, only those peptides from securely identified proteins are queried. Tentative peptide and protein identifications are ranked and scored by their relative correlation to a number of models of known and empirically derived physicochemical attributes of proteins and peptides. In addition, the algorithm utilizes decoy database techniques for automatically determining the false positive identification rates. The search algorithm has been tested by comparing the search results from a four-protein mixture, the same four-protein mixture spiked into a complex biological background, and a variety of other "system" type protein digest mixtures. The method was validated independently by data dependent methods, while concurrently relying on replication and selectivity. Comparisons were also performed with other commercially and publicly available peptide fragmentation search algorithms. The presented results demonstrate the ability to correctly identify peptides and proteins from data independent acquisition strategies with high sensitivity and specificity. They also illustrate a more comprehensive analysis of the samples studied; providing approximately 20% more protein identifications, compared to a more conventional data directed approach using the same identification criteria, with a concurrent increase in both sequence coverage and the number of modified peptides.

Molecular Diagnosis of Pathogenic Sporothrix Species

PubMed Central

Rodrigues, Anderson Messias; de Hoog, G. Sybren; de Camargo, Zoilo Pires

2015-01-01

Background Sporotrichosis is a chronic (sub)cutaneous infection caused by thermodimorphic fungi in the order, Ophiostomatales. These fungi are characterized by major differences in routes of transmission, host predilections, species virulence, and susceptibilities to antifungals. Sporothrix species emerge in the form of outbreaks. Large zoonoses and sapronoses are ongoing in Brazil and China, respectively. Current diagnostic methods based on morphology and physiology are inaccurate due to closely related phenotypes with overlapping components between pathogenic and non-pathogenic Sporothrix. There is a critical need for new diagnostic tools that are specific, sensitive, and cost-effective. Methodology We developed a panel of novel markers, based on calmodulin (CAL) gene sequences, for the large-scale diagnosis and epidemiology of clinically relevant members of the Sporothrix genus, and its relative, Ophiostoma. We identified specific PCR-based markers for S. brasiliensis, S. schenckii, S. globosa, S. mexicana, S. pallida, and O. stenoceras. We employed a murine model of disseminated sporotrichosis to optimize a PCR assay for detecting Sporothrix in clinical specimens. Results Primer-BLAST searches revealed candidate sequences that were conserved within a single species. Species-specific primers showed no significant homology with human, mouse, or microorganisms outside the Sporothrix genus. The detection limit was 10–100 fg of DNA in a single round of PCR for identifying S. brasiliensis, S. schenckii, S. globosa, S. mexicana, and S. pallida. A simple, direct PCR assay, with conidia as a source of DNA, was effective for rapid, low-cost genotyping. Samples from a murine model of disseminated sporotrichosis confirmed the feasibility of detecting S. brasiliensis and S. schenckii DNA in spleen, liver, lungs, heart, brain, kidney, tail, and feces of infected animals. Conclusions This PCR-based method could successfully detect and identify a single species in samples from cultures and from clinical specimens. The method proved to be simple, high throughput, sensitive, and accurate for diagnosing sporotrichosis. PMID:26623643

Probe-Specific Procedure to Estimate Sensitivity and Detection Limits for 19F Magnetic Resonance Imaging.

PubMed

Taylor, Alexander J; Granwehr, Josef; Lesbats, Clémentine; Krupa, James L; Six, Joseph S; Pavlovskaya, Galina E; Thomas, Neil R; Auer, Dorothee P; Meersmann, Thomas; Faas, Henryk M

2016-01-01

Due to low fluorine background signal in vivo, 19F is a good marker to study the fate of exogenous molecules by magnetic resonance imaging (MRI) using equilibrium nuclear spin polarization schemes. Since 19F MRI applications require high sensitivity, it can be important to assess experimental feasibility during the design stage already by estimating the minimum detectable fluorine concentration. Here we propose a simple method for the calibration of MRI hardware, providing sensitivity estimates for a given scanner and coil configuration. An experimental "calibration factor" to account for variations in coil configuration and hardware set-up is specified. Once it has been determined in a calibration experiment, the sensitivity of an experiment or, alternatively, the minimum number of required spins or the minimum marker concentration can be estimated without the need for a pilot experiment. The definition of this calibration factor is derived based on standard equations for the sensitivity in magnetic resonance, yet the method is not restricted by the limited validity of these equations, since additional instrument-dependent factors are implicitly included during calibration. The method is demonstrated using MR spectroscopy and imaging experiments with different 19F samples, both paramagnetically and susceptibility broadened, to approximate a range of realistic environments.

Non-crosslinking gold nanoprobe-LAMP for simple, colorimetric, and specific detection of Salmonella typhi

NASA Astrophysics Data System (ADS)

Bozorgmehr, Ali; Yazdanparast, Razieh; Mollasalehi, Hamidreza

2016-12-01

In this study, we developed a non-crosslinking gold nanoprobe loop-mediated isothermal amplification (LAMP) method for nanodiagnosis of bacterial typhoid fever source, Salmonella typhi. Therefore, a unique region in the S. typhi genomic DNA was targeted for LAMP amplification using a specific set of four precisely designed primers. Also, for specific colorimetric visualization of the amplicons, a thiolated oligonucleotide probe, complementary to the single-stranded loop region of the amplicons between F2 and F1C segments, was designed. The probe was bound to the surface of gold nanoparticles via covalent bonds. Increasing the salt concentration in the detection reaction medium led to aggregation of nanoprobes in the blank and the negative vessels in a time-dependent form. That was followed by a change in the surface plasmon resonance (SPR) leading to blue/black color that was observable by the naked eyes after about 5 min. Meanwhile, the original pink/red color was retained in the positive sample due to the large interparticle spaces and the stability against the ionic strength elevation which persisted for about 30 min. The whole process of DNA extraction, amplification, and detection took less than 2 h with a sensitivity of 20 CFU/ml. The developed gold nanoprobe-LAMP could serve as a simple, rapid, and cost-effective method for nanodiagnosis of S. typhi in point-of-need applications.

Nematodes as Sentinels of Heavy Metals and Organic Toxicants in the Soil

PubMed Central

Ekschmitt, Klemens; Korthals, Gerard W.

2006-01-01

Field and laboratory research has repeatedly shown that free-living soil nematodes differ in their sensitivity to soil pollution. In this paper, we analyze whether nematode genera proved sensitive or tolerant toward heavy metals and organic pollutants in six long-term field experiments. We discuss overlaps between nematode physiological responses to heavy metals and to organic pollutants, which may explain why nematodes can exhibit co-tolerance toward several contaminants. We propose a simple method for separating direct effects of soil contamination on nematode populations from indirect effects mediated through the food chain. Finally, we analyze the extent to which nematodes exhibited consistent responses across the experiments analyzed. Our results show that (a) indirect effects of pollution were generally strong; (b) fewer nematode genera were tolerant than sensitive; (c) many genera, including practically all Adenophorea, exhibited a common response pattern to contaminants; and (d) several genera of the Secernentea exhibited differential tolerance toward particular pollutants. We conclude that bioindication of soil contamination should preferentially be based on tolerant, and less on sensitive, nematodes. We provide a list of nematode genera that may potentially serve as differential bioindicators for specific soil contaminants. PMID:19259425

Label-free signal-on aptasensor for sensitive electrochemical detection of arsenite.

PubMed

Cui, Lin; Wu, Jie; Ju, Huangxian

2016-05-15

A signal-on aptasensor was fabricated for highly sensitive and selective electrochemical detection of arsenite with a label-free Ars-3 aptamer self-assembled on a screen-printed carbon electrode (SPCE) via Au-S bond. The Ars-3 aptamer could adsorb cationic polydiallyldimethylammonium (PDDA) via electrostatic interaction to repel other cationic species. In the presence of arsenite, the change of Ars-3 conformation due to the formation of Ars-3/arsenite complex led to less adsorption of PDDA, and the complex could adsorb more positively charged [Ru(NH3)6](3+) as an electrochemically active indicator on the aptasensor surface, which produced a sensitive "turn-on" response. The target-induced structure switching could be used for sensitive detection of arsenite with a linear range from 0.2 nM to 100 nM and a detection limit down to 0.15 nM. Benefiting from Ars-3 aptamer, the proposed system exhibited excellent specificity against other heavy metal ions. The SPCE-based aptasensor exhibited the advantages of low cost and simple fabrication, providing potential application of arsenite detection in environment. Copyright © 2016 Elsevier B.V. All rights reserved.

Design enhancement tools in MSC/NASTRAN

NASA Technical Reports Server (NTRS)

Wallerstein, D. V.

1984-01-01

Design sensitivity is the calculation of derivatives of constraint functions with respect to design variables. While a knowledge of these derivatives is useful in its own right, the derivatives are required in many efficient optimization methods. Constraint derivatives are also required in some reanalysis methods. It is shown where the sensitivity coefficients fit into the scheme of a basic organization of an optimization procedure. The analyzer is to be taken as MSC/NASTRAN. The terminator program monitors the termination criteria and ends the optimization procedure when the criteria are satisfied. This program can reside in several plances: in the optimizer itself, in a user written code, or as part of the MSC/EOS (Engineering Operating System) MSC/EOS currently under development. Since several excellent optimization codes exist and since they require such very specialized technical knowledge, the optimizer under the new MSC/EOS is considered to be selected and supplied by the user to meet his specific needs and preferences. The one exception to this is a fully stressed design (FSD) based on simple scaling. The gradients are currently supplied by various design sensitivity options now existing in MSC/NASTRAN's design sensitivity analysis (DSA).

FBG based high sensitive pressure sensor and its low-cost interrogation system with enhanced resolution

NASA Astrophysics Data System (ADS)

Pachava, Vengal Rao; Kamineni, Srimannarayana; Madhuvarasu, Sai Shankar; Putha, Kishore; Mamidi, Venkata Reddy

2015-12-01

A fiber Bragg grating (FBG) pressure sensor with high sensitivity and resolution has been designed and demonstrated. The sensor is configured by firmly fixing the FBG with a metal bellows structure. The sensor works by means of measuring the Bragg wavelength shift of the FBG with respect to pressure change. From the experimental results, the pressure sensitivity of the sensor is found to be 90.6 pm/psi, which is approximately 4000 times as that of a bare fiber Bragg grating. A very good linearity of 99.86% is observed between the Bragg wavelength of the FBG and applied pressure. The designed sensor shows good repeatability with a negligible hysteresis error of ± 0.29 psi. A low-cost interrogation system that includes a long period grating (LPG) and a photodiode (PD) accompanied with simple electronic circuitry is demonstrated for the FBG sensor, which enables the sensor to attain high resolution of up to 0.025 psi. Thermal-strain cross sensitivity of the FBG pressure sensor is compensated using a reference FBG temperature sensor. The designed sensor can be used for liquid level, specific gravity, and static/dynamic low pressure measurement applications.

Comparison of Effectiveness in Differentiating Benign from Malignant Ovarian Masses between IOTA Simple Rules and Subjective Sonographic Assessment.

PubMed

Tongsong, Theera; Tinnangwattana, Dangcheewan; Vichak-Ururote, Linlada; Tontivuthikul, Paponrad; Charoenratana, Cholaros; Lerthiranwong, Thitikarn

2016-01-01

To compare diagnostic performance in differentiating benign from malignant ovarian masses between IOTA (the International Ovarian Tumor Analysis) simple rules and subjective sonographic assessment. Women scheduled for elective surgery because of ovarian masses were recruited into the study and underwent ultrasound examination within 24 hours of surgery to apply the IOTA simple rules by general gynecologists and to record video clips for subjective assessment by an experienced sonographer. The diagnostic performance of the IOTA rules and subjective assessment for differentiation between benign and malignant masses was compared. The gold standard diagnosis was pathological or operative findings. A total of 150 ovarian masses were covered, comprising 105 (70%) benign and 45 (30%) malignant. Of them, the IOTA simple rules could be applied in 119 (79.3%) and were inconclusive in 31 (20.7%) whereas subjective assessment could be applied in all cases (100%). The sensitivity and the specificity of the IOTA simple rules and subjective assessment were not significantly different, 82.9% vs 86.7% and 94.0% vs 94.3% respectively. The agreement of the two methods in prediction was high with a Kappa index of 0.835. Both techniques had a high diagnostic performance in differentiation between benign and malignant ovarian masses but the IOTA rules had a relatively high rate of inconclusive results. The IOTA rules can be used as an effective screening technique by general gynecologists but when the results are inconclusive they should consult experienced sonographers.

A multiplex PCR for detection of six viruses in ducks.

PubMed

Wang, Yongjuan; Zhu, Shanyuan; Hong, Weiming; Wang, Anping; Zuo, Weiyong

2017-10-01

In this study, six pairs of specific primers that can amplify DNA fragments of different sizes were designed and synthesized according to viral protein gene sequences published in GenBank. Then, a multiplex PCR method was established for rapid detection of duck hepatitis virus 1, duck plague virus, duck Tembusu virus, muscovy duck parvovirus, muscovy duck reovirus, and duck H9N2 avian influenza virus, and achieve simple and rapid detection of viral diseases in ducks. Single PCR was used to confirm primer specificity, and PCR conditions were optimized to construct a multiplex PCR system. Specificity and sensitivity assays were also developed. The multiplex PCR was used to detect duck embryos infected with mixed viruses and those with clinically suspected diseases to verify the feasibility of the multiplex PCR. Results show that the primers can specifically amplify target fragments, without any cross-amplification with other viruses. The multiplex PCR system can amplify six DNA fragments from the pooled viral genomes and specifically detect nucleic acids of the six duck susceptible viruses when the template amount is 10 2 copies/μl. In addition, the system can be used to detect viral nucleic acids in duck embryos infected with the six common viruses. The detection results for clinical samples are consistent with those detected by single PCR. Therefore, the established multiplex PCR method can perform specific, sensitive, and high-throughput detection of six duck-infecting viruses and can be applied to clinical identification and diagnosis of viral infection in ducks. Copyright © 2017. Published by Elsevier B.V.

German Children’s Use of Word Order and Case Marking to Interpret Simple and Complex Sentences: Testing Differences Between Constructions and Lexical Items

PubMed Central

Brandt, Silke; Lieven, Elena; Tomasello, Michael

2016-01-01

ABSTRACT Children and adults follow cues such as case marking and word order in their assignment of semantic roles in simple transitives (e.g., the dog chased the cat). It has been suggested that the same cues are used for the interpretation of complex sentences, such as transitive relative clauses (RCs) (e.g., that’s the dog that chased the cat) (Bates, Devescovi, & D’Amico, 1999). We used a pointing paradigm to test German-speaking 3-, 4-, and 6-year-old children’s sensitivity to case marking and word order in their interpretation of simple transitives and transitive RCs. In Experiment 1, case marking was ambiguous. The only cue available was word order. In Experiment 2, case was marked on lexical NPs or demonstrative pronouns. In Experiment 3, case was marked on lexical NPs or personal pronouns. Whereas the younger children mainly followed word order, the older children were more likely to base their interpretations on the more reliable case-marking cue. In most cases, children from both age groups were more likely to use these cues in their interpretation of simple transitives than in their interpretation of transitive RCs. Finally, children paid more attention to nominative case when it was marked on first-person personal pronouns than when it was marked on third-person lexical NPs or demonstrative pronouns, such as der Löwe ‘the-NOM lion’ or der ‘he-NOM.’ They were able to successfully integrate this case-marking cue in their sentence processing even when it appeared late in the sentence. We discuss four potential reasons for these differences across development, constructions, and lexical items. (1) Older children are relatively more sensitive to cue reliability. (2) Word order is more reliable in simple transitives than in transitive RCs. (3) The processing of case marking might initially be item-specific. (4) The processing of case marking might depend on its saliency and position in the sentence. PMID:27019652

Contribution of a new electrophysiologic test to Morton's neuroma diagnosis.

PubMed

Pardal-Fernández, José Manuel; Palazón-García, Elena; Hernández-Fernández, Francisco; de Cabo, Carlos

2014-06-01

Morton's neuroma causes metatarsalgia due to the interdigital neuropathy. The small nerve diameter compromises their evaluation in image studies. To overcome this problem we propose a new electrophysiological test. We conducted a prospective case-control study performing a orthodromic electroneurography using subdermal electrodes in controls and patients to assess the validity. Additionally all patients were tested with magnetic resonance. Some patients required surgery and subsequent histological evaluation. The new ENG procedure showed higher sensitivity and specificity. Methodological standardization was easy and the test was well tolerated by the subjects. Our test demonstrated remarkable diagnostic efficiency, and also was able to identify symptomatic patients undetected by magnetic resonance, which underlines the lack of correlation between the size and intensity of the lesion. This new electrophysiological method appears to be a highly sensitivity, well-tolerated, simple and low-cost for Morton's neuroma diagnosis. Copyright © 2014 European Foot and Ankle Society. Published by Elsevier Ltd. All rights reserved.

Detection of influenza A virus subtypes using a solid-phase PCR microplate chip assay.

PubMed

Sun, Xin-Cheng; Wang, YunLong; Yang, Liping; Zhang, HuiRu

2015-01-01

A rapid and sensitive microplate chip based on solid PCR was developed to identify influenza A subtypes. A simple ultraviolet cross-linking method was used to immobilize DNA probes on pretreated microplates. Solid-phase PCR was proven to be a convenient method for influenza A screening. The sensitivity of the microplate chip was 10(-3) μg/mL for the enzymatic colorimetric method and 10(-4) μg/mL for the fluorescence method. The 10 sets of primers and probes for the microplate chip were highly specific and did not interfere with each other. These results suggest that the microplate chip based on solid PCR can be used to rapidly detect universal influenza A and its subtypes. This platform can also be used to detect other pathogenic microorganisms. Copyright © 2014 Elsevier B.V. All rights reserved.

Simultaneous Determination of Eight Hypotensive Drugs of Various Chemical Groups in Pharmaceutical Preparations by HPLC-DAD.

PubMed

Stolarczyk, Mariusz; Hubicka, Urszula; Żuromska-Witek, Barbara; Krzek, Jan

2015-01-01

A new sensitive, simple, rapid, and precise HPLC method with diode array detection has been developed for separation and simultaneous determination of hydrochlorothiazide, furosemide, torasemide, losartane, quinapril, valsartan, spironolactone, and canrenone in combined pharmaceutical dosage forms. The chromatographic analysis of the tested drugs was performed on an ACE C18, 100 Å, 250×4.6 mm, 5 μm particle size column with 0.0.05 M phosphate buffer (pH=3.00)-acetonitrile-methanol (30+20+50 v/v/v) mobile phase at a flow rate of 1.0 mL/min. The column was thermostatted at 25°C. UV detection was performed at 230 nm. Analysis time was 10 min. The elaborated method meets the acceptance criteria for specificity, linearity, sensitivity, accuracy, and precision. The proposed method was successfully applied for the determination of the studied drugs in the selected combined dosage forms.

Rapid and sensitive detection of Lily symptomless virus by reverse transcription loop-mediated isothermal amplification.

PubMed

He, Xiangfeng; Xue, Fei; Xu, Shufa; Wang, Wenhe

2016-12-01

Lily symptomless virus (LSV) is one of the most prevalent viruses that infect lily plants worldwide. A rapid and sensitive reverse transcription loop-mediated isothermal amplification (RT-LAMP) assay was developed for detection of LSV, using two primer pairs that specifically amplified the conserved sequence of LSV coat protein. The optimum reaction conditions were as follows: 4mM MgCl 2 and 0.8M betaine with incubation at 64°C for 30min. The limit of detection of LSV from infected lily leaves was 10-fold higher for RT-LAMP than for conventional RT-PCR. Moreover, RT-LAMP detected LSV in not only symptomatic, but also in symptomless tissues of infected plants. These findings indicate that our RT-LAMP method for LSV can serve as a low-cost, simple, and rapid alternative to conventional detection assays. Copyright © 2016 Elsevier B.V. All rights reserved.

Automatic Detection of Blue-White Veil and Related Structures in Dermoscopy Images

PubMed Central

Celebi, M. Emre; Iyatomi, Hitoshi; Stoecker, William V.; Moss, Randy H.; Rabinovitz, Harold S.; Argenziano, Giuseppe; Soyer, H. Peter

2011-01-01

Dermoscopy is a non-invasive skin imaging technique, which permits visualization of features of pigmented melanocytic neoplasms that are not discernable by examination with the naked eye. One of the most important features for the diagnosis of melanoma in dermoscopy images is the blue-white veil (irregular, structureless areas of confluent blue pigmentation with an overlying white “ground-glass” film). In this article, we present a machine learning approach to the detection of blue-white veil and related structures in dermoscopy images. The method involves contextual pixel classification using a decision tree classifier. The percentage of blue-white areas detected in a lesion combined with a simple shape descriptor yielded a sensitivity of 69.35% and a specificity of 89.97% on a set of 545 dermoscopy images. The sensitivity rises to 78.20% for detection of blue veil in those cases where it is a primary feature for melanoma recognition. PMID:18804955

Simple and robust resistive dual-axis accelerometer using a liquid metal droplet

NASA Astrophysics Data System (ADS)

Huh, Myoung; Won, Dong-Joon; Kim, Joong Gil; Kim, Joonwon

2017-12-01

This paper presents a novel dual-axis accelerometer that consists of a liquid metal droplet in a cone-shaped channel and an electrode layer with four Nichrome electrodes. The sensor uses the advantages of the liquid metal droplet (i.e., high surface tension, electrical conductivity, high density, and deformability). The cone-shaped channel imposes a restoring force on the liquid metal droplet. We conducted simulation tests to determine the appropriate design specifications of the cone-shaped channel. Surface modifications to the channel enhanced the nonwetting performance of the liquid metal droplet. The performances of the sensor were analyzed by a tilting test. When the acceleration was applied along the axial direction, the device showed 6 kΩ/g of sensitivity and negligible crosstalk between the X- and Y-axes. In a diagonal direction test, the device showed 4 kΩ/g of sensitivity.

Prenatal choline availability alters the context sensitivity of Pavlovian conditioning in adult rats

PubMed Central

Lamoureux, Jeffrey A.; Meck, Warren H.; Williams, Christina L.

2008-01-01

The effects of prenatal choline availability on Pavlovian conditioning were assessed in adult male rats (3–4 mo). Neither supplementation nor deprivation of prenatal choline affected the acquisition and extinction of simple Pavlovian conditioned excitation, or the acquisition and retardation of conditioned inhibition. However, prenatal choline availability significantly altered the contextual control of these learned behaviors. Both control and choline-deprived rats exhibited context specificity of conditioned excitation as exhibited by a loss in responding when tested in an alternate context after conditioning; in contrast, choline-supplemented rats showed no such effect. When switched to a different context following extinction, however, both choline-supplemented and control rats showed substantial contextual control of responding, whereas choline-deficient rats did not. These data support the view that configural associations that rely on hippocampal function are selectively sensitive to prenatal manipulations of dietary choline during prenatal development. PMID:19050158

A competitive chemiluminescence enzyme immunoassay for rapid and sensitive determination of enrofloxacin

NASA Astrophysics Data System (ADS)

Yu, Fei; Wu, Yongjun; Yu, Songcheng; Zhang, Huili; Zhang, Hongquan; Qu, Lingbo; Harrington, Peter de B.

With alkaline phosphatase (ALP)-adamantane (AMPPD) system as the chemiluminescence (CL) detection system, a highly sensitive, specific and simple competitive chemiluminescence enzyme immunoassay (CLEIA) was developed for the measurement of enrofloxacin (ENR). The physicochemical parameters, such as the chemiluminescent assay mediums, the dilution buffer of ENR-McAb, the volume of dilution buffer, the monoclonal antibody concentration, the incubation time, and other relevant variables of the immunoassay have been optimized. Under the optimal conditions, the detection linear range of 350-1000 pg/mL and the detection limit of 0.24 ng/mL were provided by the proposed method. The relative standard deviations were less than 15% for both intra and inter-assay precision. This method has been successfully applied to determine ENR in spiked samples with the recovery of 103%-96%. It showed that CLEIA was a good potential method in the analysis of residues of veterinary drugs after treatment of related diseases.

Graphene-based biosensors.

PubMed

Szunerits, Sabine; Boukherroub, Rabah

2018-06-06

Reliable data obtained from analysis of DNA, proteins, bacteria and other disease-related molecules or organisms in biological samples have become a fundamental and crucial part of human health diagnostics and therapy. The development of non-invasive tests that are rapid, sensitive, specific and simple would allow patient discomfort to be prevented, delays in diagnosis to be avoided and the status of a disease to be followed up. Bioanalysis is thus a progressive discipline for which the future holds many exciting opportunities. The use of biosensors for the early diagnosis of diseases has become widely accepted as a point-of-care diagnosis with appropriate specificity in a short time. To allow a reliable diagnosis of a disease at an early stage, highly sensitive biosensors are required as the corresponding biomarkers are generally expressed at very low concentrations. In the past 50 years, various biosensors have been researched and developed encompassing a wide range of applications. This contrasts the limited number of commercially available biosensors. When it comes to sensing of biomarkers with the required picomolar (pM) sensitivity for real-time sensing of biological samples, only a handful of sensing systems have been proposed, and these are often rather complex and costly. Lately, graphene-based materials have been considered as superior over other nanomaterials for the development of sensitive biosensors. The advantages of graphene-based sensor interfaces are numerous, including enhanced surface loading of the desired ligand due to the high surface-to-volume ratio, excellent conductivity and a small band gap that is beneficial for sensitive electrical and electrochemical read-outs, as well as tunable optical properties for optical read-outs such as fluorescence and plasmonics. In this paper, we review the advances made in recent years on graphene-based biosensors in the field of medical diagnosis.

Development and evaluation of a Loop Mediated Isothermal Amplification (LAMP) technique for the detection of hookworm (Necator americanus) infection in fecal samples.

PubMed

Mugambi, Robert Muriuki; Agola, Eric L; Mwangi, Ibrahim N; Kinyua, Johnson; Shiraho, Esther Andia; Mkoji, Gerald M

2015-11-06

Hookworm infection is a major concern in sub-Saharan Africa, particularly in children and pregnant women. Necator americanus and Ancylostoma duodenale are responsible for this condition. Hookworm disease is one of the Neglected tropical diseases (NTDs) that are targeted for elimination through global mass chemotherapy. To support this there is a need for reliable diagnostic tools. The conventional diagnostic test, Kato-Katz that is based on microscopic detection of parasite ova in faecal samples, is not effective due to its low sensitivity that is brought about mainly by non-random distribution of eggs in stool and day to day variation in egg output. It is tedious, cumbersome to perform and requires experience for correct diagnosis. LAMP-based tests are simple, relatively cheap, offer greater sensitivity, specificity than existing tests, have high throughput capability, and are ideal for use at the point of care. We have developed a LAMP diagnostic test for detection of hookworm infection in faecal samples. LAMP relies on auto cycling strand displacement DNA synthesis performed at isothermal temperature by Bst polymerase and a set of 4 specific primers. The primers used in the LAMP assay were based on the second Internal Transcribed Spacer (ITS-2) region and designed using Primer Explorer version 4 Software. The ITS-2 region of the ribosomal gene (rDNA) was identified as a suitable target due to its low mutation rates and substantial differences between species. DNA was extracted directly from human faecal samples, followed by LAMP amplification at isothermal temperature of 63 °C for 1 h. Amplicons were visualized using gel electrophoresis and SYBR green dye. Both specificity and sensitivity of the assay were determined. The LAMP based technique developed was able to detect N. americanus DNA in faecal samples. The assay showed 100 % specificity and no cross-reaction was observed with other helminth parasites (S. mansoni, A. lumbricoides or T. trichiura). The developed LAMP assay was 97 % sensitive and DNA at concentrations as low as 0.4 fg were amplified. The LAMP assay developed is an appropriate diagnostic method for the detection of N. americanus DNA in human stool samples because of its simplicity, low cost, sensitivity, and specificity. It holds great promise as a useful diagnostic tool for use in disease control where infection intensities have been significantly reduced.

Pyrazinamidase, CR-MOX agar, salicin fermentation-esculin hydrolysis, and D-xylose fermentation for identifying pathogenic serotypes of Yersinia enterocolitica.

PubMed Central

Farmer, J J; Carter, G P; Miller, V L; Falkow, S; Wachsmuth, I K

1992-01-01

We evaluated several simple laboratory tests that have been used to identify pathogenic serotypes of Yersinia enterocolitica or to indicate the pathogenic potential of individual strains. A total of 100 strains of Y. enterocolitica were studied, including 25 isolated during five outbreak investigations, 63 from sporadic cases, and 12 from stock cultures. The pyrazinamidase test, which does not depend on the Yersinia virulence plasmid, correctly identified 60 of 63 (95% sensitivity) strains of pathogenic serotypes and 34 of 37 (92% specificity) strains of nonpathogenic serotypes. Salicin fermentation-esculin hydrolysis (25 degrees C, 48 h) correctly identified all 63 (100% sensitivity) strains of the pathogenic serotypes and 34 of 37 (92% specificity) strains of the nonpathogenic serotypes. The results of the pyrazinamidase and salicin-esculin tests disagreed for only 7 of the 100 strains of Y. enterocolitica, and these would require additional testing. Congo red-magnesium oxalate (CR-MOX) agar determines Congo red dye uptake and calcium-dependent growth at 36 degrees C, and small red colonies are present only if the strain contains the Yersinia virulence plasmid. This test has proven to be extremely useful for freshly isolated cultures, but only 15 of 62 strains of pathogenic serotypes that had been stored for 1 to 10 years were CR-MOX positive. None of the 16 strains of Y. enterocolitica serotype O3 fermented D-xylose, so this test easily differentiated strains of this serotype, which now appears to be the most common in the United States. Although antisera that can actually be used to serotype strains of Y. enterocolitica are not readily available, the four simple tests described above can be used to screen for pathogenic serotypes. Images PMID:1400958

The Evonik-Mainz Eye Care-Study (EMECS): Development of an Expert System for Glaucoma Risk Detection in a Working Population

PubMed Central

Wahl, Jochen; Barleon, Lorenz; Morfeld, Peter; Lichtmeß, Andrea; Haas-Brähler, Sibylle; Pfeiffer, Norbert

2016-01-01

Purpose To develop an expert system for glaucoma screening in a working population based on a human expert procedure using images of optic nerve head (ONH), visual field (frequency doubling technology, FDT) and intraocular pressure (IOP). Methods 4167 of 13037 (32%) employees between 40 and 65 years of Evonik Industries were screened. An experienced glaucoma expert (JW) assessed papilla parameters and evaluated all individual screening results. His classification into “no glaucoma”, “possible glaucoma” and “probable glaucoma” was defined as “gold standard”. A screening model was developed which was tested versus the gold-standard. This model took into account the assessment of the ONH. Values and relationships of CDR and IOP and the FDT were considered additionally and a glaucoma score was generated. The structure of the screening model was specified a priori whereas values of the parameters were chosen post-hoc to optimize sensitivity and specificity of the algorithm. Simple screening models based on IOP and / or FDT were investigated for comparison. Results 111 persons (2.66%) were classified as glaucoma suspects, thereof 13 (0.31%) as probable and 98 (2.35%) as possible glaucoma suspects by the expert. Re-evaluation by the screening model revealed a sensitivity of 83.8% and a specificity of 99.6% for all glaucoma suspects. The positive predictive value of the model was 80.2%, the negative predictive value 99.6%. Simple screening models showed insufficient diagnostic accuracy. Conclusion Adjustment of ONH and symmetry parameters with respect to excavation and IOP in an expert system produced sufficiently satisfying diagnostic accuracy. This screening model seems to be applicable in such a working population with relatively low age and low glaucoma prevalence. Different experts should validate the model in different populations. PMID:27479301

[Correlation between percentage of body fat and simple anthropometric parameters in children aged 6-9 years in Guangzhou].

PubMed

Yan, H C; Hao, Y T; Guo, Y F; Wei, Y H; Zhang, J H; Huang, G P; Mao, L M; Zhang, Z Q

2017-11-10

Objective: To evaluate the accuracy of simple anthropometric parameters in diagnosing obesity in children in Guangzhou. Methods: A cross-sectional study, including 465 children aged 6-9 years, was carried out in Guangzhou. Their body height and weight, waist circumference (WC) and hip circumference were measured according to standard procedure. Body mass index (BMI), waist to hip ratio (WHR) and waist-to-height ratio (WHtR) were calculated. Body fat percentage (BF%) was determined by dual-energy X-ray absorptiometry. Multiple regression analysis was applied to evaluate the correlations between age-adjusted physical indicators and BF%, after the adjustment for age. Obesity was defined by BF%. Receiver operating characteristic (ROC) curve analyses were performed to assess the diagnostic accuracy of the indicators for childhood obesity. Area under-ROC curves (AUCs) were calculated and the best cut-off point that maximizing 'sensitivity + specificity-1' was determined. Results: BMI showed the strongest association with BF% through multiple regression analysis. For 'per-standard deviation increase' of BMI, BF% increased by 5.3% ( t =23.1, P <0.01) in boys and 4.6% ( t =17.5, P <0.01) in girls, respectively. The ROC curve analysis indicated that BMI exhibited the largest AUC in both boys (AUC=0.908) and girls (AUC=0.895). The sensitivity was 80.8% in boys and 81.8% in girls, and the specificity was 88.2% in boys and 87.1% in girls. Both the AUCs for WHtR and WC were less than 0.8 in boys and girls. WHR had the smallest AUCs (<0.8) in both boys and girls. Conclusion: BMI appeared to be a good predicator for BF% in children aged 6-9 years in Guangzhou.

Development of clinical decision rules to predict recurrent shock in dengue

PubMed Central

2013-01-01

Introduction Mortality from dengue infection is mostly due to shock. Among dengue patients with shock, approximately 30% have recurrent shock that requires a treatment change. Here, we report development of a clinical rule for use during a patient’s first shock episode to predict a recurrent shock episode. Methods The study was conducted in Center for Preventive Medicine in Vinh Long province and the Children’s Hospital No. 2 in Ho Chi Minh City, Vietnam. We included 444 dengue patients with shock, 126 of whom had recurrent shock (28%). Univariate and multivariate analyses and a preprocessing method were used to evaluate and select 14 clinical and laboratory signs recorded at shock onset. Five variables (admission day, purpura/ecchymosis, ascites/pleural effusion, blood platelet count and pulse pressure) were finally trained and validated by a 10-fold validation strategy with 10 times of repetition, using a logistic regression model. Results The results showed that shorter admission day (fewer days prior to admission), purpura/ecchymosis, ascites/pleural effusion, low platelet count and narrow pulse pressure were independently associated with recurrent shock. Our logistic prediction model was capable of predicting recurrent shock when compared to the null method (P < 0.05) and was not outperformed by other prediction models. Our final scoring rule provided relatively good accuracy (AUC, 0.73; sensitivity and specificity, 68%). Score points derived from the logistic prediction model revealed identical accuracy with AUCs at 0.73. Using a cutoff value greater than −154.5, our simple scoring rule showed a sensitivity of 68.3% and a specificity of 68.2%. Conclusions Our simple clinical rule is not to replace clinical judgment, but to help clinicians predict recurrent shock during a patient’s first dengue shock episode. PMID:24295509

Locating qualitative studies in dementia on MEDLINE, EMBASE, CINAHL, and PsycINFO: A comparison of search strategies.

PubMed

Rogers, Morwenna; Bethel, Alison; Abbott, Rebecca

2017-10-28

Qualitative research in dementia improves understanding of the experience of people affected by dementia. Searching databases for qualitative studies is problematic. Qualitative-specific search strategies might help with locating studies. To examine the effectiveness (sensitivity and precision) of 5 qualitative strategies on locating qualitative research studies in dementia in 4 major databases (MEDLINE, EMBASE, PsycINFO, and CINAHL). Qualitative dementia studies were checked for inclusion on MEDLINE, EMBASE, PsycINFO, and CINAHL. Five qualitative search strategies (subject headings, simple free-text terms, complex free-text terms, and 2 broad-based strategies) were tested for study retrieval. Specificity, precision and number needed to read were calculated. Two hundred fourteen qualitative studies in dementia were included. PsycINFO and CINAHL held the most qualitative studies out the 4 databases studied (N = 171 and 166, respectively) and both held unique records (N = 14 and 7, respectively). The controlled vocabulary strategy in CINAHL returned 96% (N = 192) of studies held; by contrast, controlled vocabulary in PsycINFO returned 7% (N = 13) of studies held. The broad-based strategies returned more studies (93-99%) than the other free-text strategies (22-82%). Precision ranged from 0.061 to 0.004 resulting in a number needed to read to obtain 1 relevant study ranging from 16 (simple free-text search in CINAHL) to 239 (broad-based search in EMBASE). Qualitative search strategies using 3 broad terms were more sensitive than long complex searches. The controlled vocabulary for qualitative research in CINAHL was particularly effective. Furthermore, results indicate that MEDLINE and EMBASE offer little benefit for locating qualitative dementia research if CINAHL and PSYCINFO are also searched. Copyright © 2017 John Wiley & Sons, Ltd.

Multicenter Validation of Commercial Antigenuria Reagents To Diagnose Progressive Disseminated Histoplasmosis in People Living with HIV/AIDS in Two Latin American Countries.

PubMed

Cáceres, Diego H; Samayoa, Blanca E; Medina, Narda G; Tobón, Angela M; Guzmán, Brenda J; Mercado, Danicela; Restrepo, Angela; Chiller, Tom; Arathoon, Eduardo E; Gómez, Beatriz L

2018-06-01

Histoplasmosis is an important cause of mortality in patients with AIDS, especially in countries with limited access to antiretroviral therapies and diagnostic tests. However, many disseminated infections in Latin America go undiagnosed. A simple, rapid method to detect Histoplasma capsulatum infection in regions where histoplasmosis is endemic would dramatically decrease the time to diagnosis and treatment, reducing morbidity and mortality. The aim of this study was to validate a commercial monoclonal Histoplasma galactomannan (HGM) enzyme-linked immunosorbent assay (Immuno-Mycologics [IMMY], Norman, OK, USA) in two cohorts of people living with HIV/AIDS (PLHIV). We analyzed urine samples from 589 people (466 from Guatemala and 123 from Colombia), including 546 from PLHIV and 43 from non-PLHIV controls. Sixty-three of these people (35 from Guatemala and 28 from Colombia) had confirmed histoplasmosis by isolation of H. capsulatum Using the standard curve provided by the quantitative commercial test, the sensitivity was 98% (95% confidence interval [CI], 95 to 100%) and the specificity was 97% (95% CI, 96 to 99%) (cutoff = 0.5 ng/ml). Semiquantitative results, using a calibrator of 12.5 ng/ml of Histoplasma galactomannan to calculate an enzyme immunoassay index value (EIV) for the samples, showed a sensitivity of 95% (95% CI, 89 to 100%) and a specificity of 98% (95% CI, 96 to 99%) (cutoff ≥ 2.6 EIV). This relatively simple-to-perform commercial antigenuria test showed a high performance with reproducible results in both countries, suggesting that it can be used to detect progressive disseminated histoplasmosis in PLHIV in a wide range of clinical laboratories in countries where histoplasmosis is endemic. Copyright © 2018 American Society for Microbiology.

The Evonik-Mainz Eye Care-Study (EMECS): Development of an Expert System for Glaucoma Risk Detection in a Working Population.

PubMed

Wahl, Jochen; Barleon, Lorenz; Morfeld, Peter; Lichtmeß, Andrea; Haas-Brähler, Sibylle; Pfeiffer, Norbert

2016-01-01

To develop an expert system for glaucoma screening in a working population based on a human expert procedure using images of optic nerve head (ONH), visual field (frequency doubling technology, FDT) and intraocular pressure (IOP). 4167 of 13037 (32%) employees between 40 and 65 years of Evonik Industries were screened. An experienced glaucoma expert (JW) assessed papilla parameters and evaluated all individual screening results. His classification into "no glaucoma", "possible glaucoma" and "probable glaucoma" was defined as "gold standard". A screening model was developed which was tested versus the gold-standard. This model took into account the assessment of the ONH. Values and relationships of CDR and IOP and the FDT were considered additionally and a glaucoma score was generated. The structure of the screening model was specified a priori whereas values of the parameters were chosen post-hoc to optimize sensitivity and specificity of the algorithm. Simple screening models based on IOP and / or FDT were investigated for comparison. 111 persons (2.66%) were classified as glaucoma suspects, thereof 13 (0.31%) as probable and 98 (2.35%) as possible glaucoma suspects by the expert. Re-evaluation by the screening model revealed a sensitivity of 83.8% and a specificity of 99.6% for all glaucoma suspects. The positive predictive value of the model was 80.2%, the negative predictive value 99.6%. Simple screening models showed insufficient diagnostic accuracy. Adjustment of ONH and symmetry parameters with respect to excavation and IOP in an expert system produced sufficiently satisfying diagnostic accuracy. This screening model seems to be applicable in such a working population with relatively low age and low glaucoma prevalence. Different experts should validate the model in different populations.

Systematic Review of the Performance of Noninvasive Tests in Diagnosing Bladder Outlet Obstruction in Men with Lower Urinary Tract Symptoms.

PubMed

Malde, Sachin; Nambiar, Arjun K; Umbach, Roland; Lam, Thomas B; Bach, Thorsten; Bachmann, Alexander; Drake, Marcus J; Gacci, Mauro; Gratzke, Christian; Madersbacher, Stephan; Mamoulakis, Charalampos; Tikkinen, Kari A O; Gravas, Stavros

2017-03-01

Several noninvasive tests have been developed for diagnosing bladder outlet obstruction (BOO) in men to avoid the burden and morbidity associated with invasive urodynamics. The diagnostic accuracy of these tests, however, remains uncertain. To systematically review available evidence regarding the diagnostic accuracy of noninvasive tests in diagnosing BOO in men with lower urinary tract symptoms (LUTS) using a pressure-flow study as the reference standard. The EMBASE, MEDLINE, Cochrane Database of Systematic Reviews, Cochrane Central, Google Scholar, and WHO International Clinical Trials Registry Platform Search Portal databases were searched up to May 18, 2016. All studies reporting diagnostic accuracy for noninvasive tests for BOO or detrusor underactivity in men with LUTS compared to pressure-flow studies were included. Two reviewers independently screened all articles, searched the reference lists of retrieved articles, and performed the data extraction. The quality of evidence and risk of bias were assessed using the QUADAS-2 tool. The search yielded 2774 potentially relevant reports. After screening titles and abstracts, 53 reports were retrieved for full-text screening, of which 42 (recruiting a total of 4444 patients) were eligible. Overall, the results were predominantly based on findings from nonrandomised experimental studies and, within the limits of such study designs, the quality of evidence was typically moderate across the literature. Differences in noninvasive test threshold values and variations in the urodynamic definition of BOO between studies limited the comparability of the data. Detrusor wall thickness (median sensitivity 82%, specificity 92%), near-infrared spectroscopy (median sensitivity 85%, specificity 87%), and the penile cuff test (median sensitivity 88%, specificity 75%) were all found to have high sensitivity and specificity in diagnosing BOO. Uroflowmetry with a maximum flow rate of <10ml/s was reported to have lower median sensitivity and specificity of 68% and 70%, respectively. Intravesical prostatic protrusion of >10mm was reported to have similar diagnostic accuracy, with median sensitivity of 68% and specificity of 75%. According to the literature, a number of noninvasive tests have high sensitivity and specificity in diagnosing BOO in men. However, although the majority of studies have a low overall risk of bias, the available evidence is limited by heterogeneity. While several tests have shown promising results regarding noninvasive assessment of BOO, invasive urodynamics remain the gold standard. Urodynamics is an accurate but potentially uncomfortable test for patients in diagnosing bladder problems such as obstruction. We performed a thorough and comprehensive review of the literature to determine if there were less uncomfortable but equally effective alternatives to urodynamics for diagnosing bladder problems. We found that some simple tests appear to be promising, although they are not as accurate. Further research is needed before these tests are routinely used in place of urodynamics. Copyright © 2016 European Association of Urology. Published by Elsevier B.V. All rights reserved.

Validation of Indian diabetic risk score in diagnosing type 2 diabetes mellitus against high fasting blood sugar levels among adult population of central India.

PubMed

Bhadoria, Ajeet Singh; Kasar, Pradeep Kumar; Toppo, Neelam Anupama

2015-01-01

Globally the increasing prevalence of diabetes mellitus (DM) is major public health concern. The Indian Diabetes Risk Score (IDRS) was developed by Madras Diabetes Research Foundation (MDRF) as a simple tool to help detect undiagnosed type 2 DM (T2DM) in the community. We conducted a study among 911 adults of Jabalpur District to validate the IDRS score against increased fasting blood sugar levels in diagnosing T2DM. T2DM was confirmed either by history of previously known disease or fasting plasma glucose ≥126 mg/dl on two occasions. Sensitivity, specificity, positive predictive value, negative predictive value, Youden index (sensitivity + specificity -1), likelihood ratio for positive test, and likelihood ratio for negative test were calculated for IDRS cut-offs of ≥20, ≥40, ≥60, and ≥80 against the presence of T2DM (either known diabetic or fasting plasma glucose >126 mg/dl on two occasions). The overall prevalence of T2DM was 9.99% (95% confidence interval, 8.04-11.94%). In the Receiver operating characteristic analysis, IDRS had an area under the curve of 0.736 (P < 0.001). The best cut-off was IDRS 40 with a sensitivity, specificity, and Youden index of 60.4%, 70.7%, and 0.31, respectively. The findings of our study indicate that IDRS has excellent predictive value for detecting undiagnosed diabetes in the community and IDRS is also a much stronger risk indicator than examining individual risk factors like age, family history, obesity, or physical activity.

Patent foramen ovale: comparison among diagnostic strategies in cryptogenic stroke and migraine.

PubMed

Zito, Concetta; Dattilo, Giuseppe; Oreto, Giuseppe; Di Bella, Gianluca; Lamari, Annalisa; Iudicello, Raffaella; Trio, Olimpia; Caracciolo, Giuseppe; Coglitore, Sebastiano; Arrigo, Francesco; Carerj, Scipione

2009-05-01

The aim of this study was to compare transthoracic echocardiography (TTE) and transcranial Doppler ultrasonography (TCD) with transesophageal echocardiography (TEE) in order to define the best clinical approach to patent foramen ovale (PFO) detection. In total, 72 consecutive patients (33 men) with a mean age of 49 +/- 13 years were prospectively enrolled. The TEE indication was cryptogenic stroke (36 patients) or migraine (36 patients, 22 with aura). All patients underwent standard TTE, TCD, and TEE examination. For any study, a contrast test was carried on using an agitated saline solution mixed with urea-linked gelatine (Haemaccel), injected as a rapid bolus via a right antecubital vein. A prolonged Valsalva maneuver was performed to improve test sensitivity. TEE identified a PFO in 65% of the whole population: 56.5% in the migraine cohort and 43.5% in the cryptogenic stroke cohort. TTE was able to detect a PFO in 55% of patients positive at TEE (54% negative predictive value, 100% positive predictive value, 55% sensitivity, and 100% specificity). TCD was able to identify a PFO in 97% of patients positive at TEE (89% negative predictive value, 98% positive predictive value, 94% sensitivity, and 96% specificity). In patients with cryptogenic stroke and migraine, there is a fair concordance (k = 0.89) between TCD and TEE in PFO recognition. Accordingly, TCD should be recommended as a simple, noninvasive, and reliable technique, whereas TEE indication should be restricted to selected patients. TTE is a very specific technique, whose major advantage is the ability to detect a large right-to-left shunt, particularly if associated with an atrial septal aneurysm.

Towards Measuring Brain Function on Groups of People in the Real World

PubMed Central

Gevins, Alan; Chan, Cynthia S.; Sam-Vargas, Lita

2012-01-01

In three studies, EEGs from three groups of participants were recorded during progressively more real world situations after drinking alcoholic beverages that brought breath alcohol contents near the limit for driving in California 30 minutes after drinking. A simple equation that measured neurophysiological effects of alcohol in the first group of 15 participants performing repetitive cognitive tasks was applied to a second group of 15 operating an automobile driving simulator, and to a third group of 10 ambulatory people recorded simultaneously during a cocktail party. The equation derived from the first group quantified alcohol’s effect by combining measures of higher frequency (beta) and lower frequency (theta) power into a single score. It produced an Area Under the Receiver Operator Characteristic Curve of .73 (p<.05; 67% sensitivity in recognizing alcohol and 87% specificity in recognizing placebo). Applying the same equation to the second group operating the driving simulator, AUC was .95, (p<.0001; 93% sensitivity and 73% specificity), while for the cocktail party group AUC was .87 (p<.01; 80% sensitivity and 80% specificity). EEG scores were significantly related to breath alcohol content in all studies. Some individuals differed markedly from the overall response evident in their respective groups. The feasibility of measuring the neurophysiological effect of a psychoactive substance from an entire group of ambulatory people at a cocktail party suggests that future studies may be able to fruitfully apply brain function measures derived under rigorously controlled laboratory conditions to assess drug effects on groups of people interacting in real world situations. PMID:22957099

Evaluation of Applying a Combination of Red Cell Indexes and Formulas to Differentiate β-Thalassemia Trait from Iron Deficiency Anemia in the Thai Population.

PubMed

Pornprasert, Sakorn; Thongsat, Choosak; Panyachadporn, Uraiporn

2017-03-01

Red cell indexes and formulas have been established as simple, fast, and inexpensive tools to differentiate β-thalassemia (β-thal) trait from iron deficiency anemia. However, none of them showed 100.0% sensitivity and specificity. Moreover, one index may show greater sensitivity and specificity in one population but is ineffective in another population. This study evaluated the diagnostic reliability of a combination of two red cell indexes [red blood cell (RBC) and red blood cell distribution width (RDW)] and nine formulas called '11T score' for differentiation of β-thal trait and iron deficiency anemia in the Thai population. A total of 103 cases, 67 β-thal trait and 36 iron deficiency anemia, Thai subjects with microcytic hypochromic anemia [mean corpuscular volume (MCV) <80.0 fL and mean corpuscular hemoglobin (Hb) (MCH) <27.0 pg] were involved in this retrospective study. The results showed that the 11T score with a cutoff value of 7 was able to discriminate between β-thal trait and iron deficiency anemia with sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and efficiency (EFF) higher than 70.0%. It also had 85.4% of correctly identified cases and the highest value of Youden's Index (YI) (73.8%) when compared to the 11T score with other cutoff values (5, 6, 8 and 9) and other indexes. Thus, the 11T score with the cutoff value of 7 could be used to differentiate β-thal trait from iron deficiency anemia in the Thai population.

Efficient statistical tests to compare Youden index: accounting for contingency correlation.

PubMed

Chen, Fangyao; Xue, Yuqiang; Tan, Ming T; Chen, Pingyan

2015-04-30

Youden index is widely utilized in studies evaluating accuracy of diagnostic tests and performance of predictive, prognostic, or risk models. However, both one and two independent sample tests on Youden index have been derived ignoring the dependence (association) between sensitivity and specificity, resulting in potentially misleading findings. Besides, paired sample test on Youden index is currently unavailable. This article develops efficient statistical inference procedures for one sample, independent, and paired sample tests on Youden index by accounting for contingency correlation, namely associations between sensitivity and specificity and paired samples typically represented in contingency tables. For one and two independent sample tests, the variances are estimated by Delta method, and the statistical inference is based on the central limit theory, which are then verified by bootstrap estimates. For paired samples test, we show that the estimated covariance of the two sensitivities and specificities can be represented as a function of kappa statistic so the test can be readily carried out. We then show the remarkable accuracy of the estimated variance using a constrained optimization approach. Simulation is performed to evaluate the statistical properties of the derived tests. The proposed approaches yield more stable type I errors at the nominal level and substantially higher power (efficiency) than does the original Youden's approach. Therefore, the simple explicit large sample solution performs very well. Because we can readily implement the asymptotic and exact bootstrap computation with common software like R, the method is broadly applicable to the evaluation of diagnostic tests and model performance. Copyright © 2015 John Wiley & Sons, Ltd.

Highly sensitive and specific on-site detection of serum cocaine by a low cost aptasensor.

PubMed

Oueslati, Rania; Cheng, Cheng; Wu, Jayne; Chen, Jiangang

2018-06-15

Cocaine is one of the most used illegal recreational drugs. Developing an on-site test for cocaine use detection has been a focus of research effort, since it is essential to the control and legal action against drug abuse. Currently most of cocaine detection methods are time-consuming and require special or expensive equipment, and the detection often suffers from high cross-reactivity with cocaine metabolites and relative low sensitivity with the best limit of detection reported at sub nanomolar (nM) level. In this work, an aptasensor has been developed using capacitive monitoring of sensor surface incorporating alternating current electrokinetics effects to speed up molecular transport and minimize matrix effects. The aptasensor is rapid, low cost, highly sensitive and specific as well as simple-to-use for the detection of cocaine from serum. The assay has a sample-to-result time of 30 s, a limit of detection of 7.8 fM, and a linear response for cocaine ranging from 14.5fM to 14.5pM in standard buffer, which are great improvements from other reported cocaine sensors. Special buffer is used for serum cocaine detection, and a limit of detection of 13.4 fM is experimentally demonstrated for cocaine spiked in human serum (equivalent to 1.34pM cocaine in neat serum). The specificity of the biosensor is also demonstrated with structurally similar chemicals, ecgonine ethyl ester and methylecgonidine. This biosensor shows high promise in detection of low levels of cocaine from complex matrices. Copyright © 2018 Elsevier B.V. All rights reserved.

A simple screening test for the detection of metallo-β-lactamase-producing Pseudomonas aeruginosa and Acinetobacter in a tertiary care hospital.

PubMed

Wan Nor Amilah, W A W; Noor Izani, N J; Ng, W K; Ashraful Haq, J

2012-12-01

Clinical utilization of carbapenems remains under threat with the emergence of acquired carbapenemase-producing bacteria, particularly metallo-β-lactamases (MBL). Rapid detection of MBL-producing Gram-negative bacilli is essential to prevent their widespread dissemination. However, no standardized detection method is available for routine laboratory use. The purpose of the study was to evaluate a chelating-agent based double disk synergic test and disk potentiation test for MBL-producing strain detection and to determine the isolation rate of MBL-producing Pseudomonas aeruginosa and Acinetobacter from clinical samples in our tertiary teaching hospital. A total of 22 and 66 imipenem-resistant P. aeruginosa and Acinetobacter isolates respectively were tested with ceftazidime (CAZ) disk by modified double disk synergic test and disk potentiation test using ethylenediaminetetraacetic acid (EDTA) and 2-mercaptopropionic acid (as chelating agents) to detect MBL production. The tests were compared with EDTA-phenanthroline-imipenem (EPI) microdilution MIC test as gold standard. MBL positive strains were detected in 17 (77.3%) P. aeruginosa and 2 (3.5%) Acinetobacter isolates. The disk potentiation test with 2-mercaptopropionic acid (2-MPA) dilution of 1:12 provided the most acceptable sensitivities and specificities (88.2% sensitivity and 100% specificity in P. aeruginosa; 100% sensitivity and specificity in Acinetobacter) compared to other screening methods used in this study. This study provided useful information on the local prevalence of MBL-producing P. aeruginosa and Acinetobacter in our hospital. Disc potentiation test with CAZ/2-MPA disc appears to be reliable and convenient MBL detection method in the routine clinical laboratory.

Predicting the probability of mortality of gastric cancer patients using decision tree.

PubMed

Mohammadzadeh, F; Noorkojuri, H; Pourhoseingholi, M A; Saadat, S; Baghestani, A R

2015-06-01

Gastric cancer is the fourth most common cancer worldwide. This reason motivated us to investigate and introduce gastric cancer risk factors utilizing statistical methods. The aim of this study was to identify the most important factors influencing the mortality of patients who suffer from gastric cancer disease and to introduce a classification approach according to decision tree model for predicting the probability of mortality from this disease. Data on 216 patients with gastric cancer, who were registered in Taleghani hospital in Tehran,Iran, were analyzed. At first, patients were divided into two groups: the dead and alive. Then, to fit decision tree model to our data, we randomly selected 20% of dataset to the test sample and remaining dataset considered as the training sample. Finally, the validity of the model examined with sensitivity, specificity, diagnosis accuracy and the area under the receiver operating characteristic curve. The CART version 6.0 and SPSS version 19.0 softwares were used for the analysis of the data. Diabetes, ethnicity, tobacco, tumor size, surgery, pathologic stage, age at diagnosis, exposure to chemical weapons and alcohol consumption were determined as effective factors on mortality of gastric cancer. The sensitivity, specificity and accuracy of decision tree were 0.72, 0.75 and 0.74 respectively. The indices of sensitivity, specificity and accuracy represented that the decision tree model has acceptable accuracy to prediction the probability of mortality in gastric cancer patients. So a simple decision tree consisted of factors affecting on mortality of gastric cancer may help clinicians as a reliable and practical tool to predict the probability of mortality in these patients.

Sensitivity and specificity of the 'knee-up test' for estimation of the American Spinal Injury Association Impairment Scale in patients with acute motor incomplete cervical spinal cord injury.

PubMed

Yugué, Itaru; Okada, Seiji; Maeda, Takeshi; Ueta, Takayoshi; Shiba, Keiichiro

2018-04-01

A retrospective study. Precise classification of the neurological state of patients with acute cervical spinal cord injury (CSCI) can be challenging. This study proposed a useful and simple clinical method to help classify patients with incomplete CSCI. Spinal Injuries Centre, Japan. The sensitivity and specificity of the 'knee-up test' were evaluated in patients with acute CSCI classified as American Spinal Injury Association Impairment Scale (AIS) C or D. The result is positive if the patient can lift the knee in one or both legs to an upright position, whereas the result is negative if the patient is unable to lift the knee in either leg to an upright position. The AIS of these patients was classified according to a strict computerised algorithm designed by Walden et al., and the knee-up test was tested by non-expert examiners. Among the 200 patients, 95 and 105 were classified as AIS C and AIS D, respectively. Overall, 126 and 74 patients demonstrated positive and negative results, respectively, when evaluated using the knee-up test. A total of 104 patients with positive results and 73 patients with negative results were classified as AIS D and AIS C, respectively. The sensitivity, specificity, positive predictive and negative predictive values of this test for all patients were 99.1, 76.8, 82.5 and 98.7, respectively. The knee-up test may allow easy and highly accurate estimation, without the need for special skills, of AIS classification for patients with incomplete CSCI.

Dual-Recognition Förster Resonance Energy Transfer Based Platform for One-Step Sensitive Detection of Pathogenic Bacteria Using Fluorescent Vancomycin-Gold Nanoclusters and Aptamer-Gold Nanoparticles.

PubMed

Yu, Mengqun; Wang, Hong; Fu, Fei; Li, Linyao; Li, Jing; Li, Gan; Song, Yang; Swihart, Mark T; Song, Erqun

2017-04-04

The effective monitoring, identification, and quantification of pathogenic bacteria is essential for addressing serious public health issues. In this study, we present a universal and facile one-step strategy for sensitive and selective detection of pathogenic bacteria using a dual-molecular affinity-based Förster (fluorescence) resonance energy transfer (FRET) platform based on the recognition of bacterial cell walls by antibiotic and aptamer molecules, respectively. As a proof of concept, Vancomycin (Van) and a nucleic acid aptamer were employed in a model dual-recognition scheme for detecting Staphylococcus aureus (Staph. aureus). Within 30 min, by using Van-functionalized gold nanoclusters and aptamer-modified gold nanoparticles as the energy donor and acceptor, respectively, the FRET signal shows a linear variation with the concentration of Staph. aureus in the range from 20 to 10 8 cfu/mL with a detection limit of 10 cfu/mL. Other nontarget bacteria showed negative results, demonstrating the good specificity of the approach. When employed to assay Staph. aureus in real samples, the dual-recognition FRET strategy showed recoveries from 99.00% to the 109.75% with relative standard derivations (RSDs) less than 4%. This establishes a universal detection platform for sensitive, specific, and simple pathogenic bacteria detection, which could have great impact in the fields of food/public safety monitoring and infectious disease diagnosis.