[Rapid identification of potato cultivars using NIR-excited fluorescence and Raman spectroscopy].

PubMed

Dai, Fen; Bergholt, Mads Sylvest; Benjamin, Arnold Julian Vinoj; Hong, Tian-Sheng; Zhiwei, Huang

2014-03-01

Potato is one of the most important food in the world. Rapid and noninvasive identification of potato cultivars plays a important role in the better use of varieties. In this study, The identification ability of optical spectroscopy techniques, including near-infrared (NIR) Raman spectroscopy and NIR fluorescence spectroscopy, for invasive detection of potato cultivars was evaluated. A rapid NIR Raman spectroscopy system was applied to measure the composite Raman and NIR fluorescence spectroscopy of 3 different species of potatoes (98 samples in total) under 785 nm laser light excitation. Then pure Raman and NIR fluorescence spectroscopy were abstracted from the composite spectroscopy, respectively. At last, the partial least squares-discriminant analysis (PLS-DA) was utilized to analyze and classify Raman spectra of 3 different types of potatoes. All the samples were divided into two sets at random: the calibration set (74samples) and prediction set (24 samples), the model was validated using a leave-one-out, cross-validation method. The results showed that both the NIR-excited fluorescence spectra and pure Raman spectra could be used to identify three cultivars of potatoes. The fluorescence spectrum could distinguish the Favorita variety well (sensitivity: 1, specificity: 0.86 and accuracy: 0.92), but the result for Diamant (sensitivity: 0.75, specificity: 0.75 and accuracy: 0. 75) and Granola (sensitivity: 0.16, specificity: 0.89 and accuracy: 0.71) cultivars identification were a bit poorer. We demonstrated that Raman spectroscopy uncovered the main biochemical compositions contained in potato species, and provided a better classification sensitivity, specificity and accuracy (sensitivity: 1, specificity: 1 and accuracy: 1 for all 3 potato cultivars identification) among the three types of potatoes as compared to fluorescence spectroscopy.

Rapid quantification of color vision: the cone contrast test.

PubMed

Rabin, Jeff; Gooch, John; Ivan, Douglas

2011-02-09

To describe the design, specificity, and sensitivity of the cone contrast test (CCT), a computer-based, cone-specific (L, M, S) contrast sensitivity test for diagnosing type and severity of color vision deficiency (CVD). The CCT presents a randomized series of colored letters visible only to L, M or S cones in decreasing steps of cone contrast to determine L, M, and S letter-recognition thresholds. Sensitivity and specificity were determined by retrospective comparison of CCT scores to anomaloscope and pseudoisochromatic plate (PIP) results in 1446 applicants for pilot training. CVD was detected in 49 (3.4%) of 1446 applicants with hereditary red-green (protan or deutan) CVD detected in 47 (3.5%) of 1359 men and blue-yellow (tritan) in 2 of 1446. In agreement with the anomaloscope, the CCT showed 100% sensitivity for detection and categorization of CVD (40 deutan, 7 protan, 2 tritan). PIP testing showed lower sensitivity (80% detected; 20% missed) due in part to the applicant's prior experience and/or pretest preparation. CCT specificity for confirming normal color vision was 100% for L and M cone tests and 99.8% for S cones. The CCT has sensitivity and specificity comparable to anomaloscope testing and exceeds PIP sensitivity in practiced observers. The CCT provides a rapid (6 minutes), clinically expedient, measure of color vision for quantifying normal color performance, diagnosing type and severity of hereditary deficiency, and detection of acquired sensitivity loss due to ocular, neurologic, and/or systemic disease, as well as injury and physiological stressors, such as altitude and fatigue.

Rapid diagnosis of sensitivity to ultraviolet light in fibroblasts from dermatologic disorders, with particular reference to xeroderma pigmentosum

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

Cleaver, J.E.; Thomas, G.H.

1988-04-01

A rapid and simple method for determining the sensitivity of human fibroblasts to ultraviolet light is described. As an alternative to the colony formation assay, this method can be used for the rapid diagnosis of ultraviolet light sensitivity in fibroblasts from photosensitive disorders. The method is based on growth of small numbers of cells in 1-cm wells of culture trays for 4 or more days after irradiation and determination of cell survival by the incorporation of (/sup 3/H)hypoxanthine. D37 values (the dose at which 37% of the control level of incorporation remains) obtained from this procedure showed the same relativemore » sensitivity of normal and xeroderma pigmentosum fibroblasts as was obtained by colony formation. Untransformed and SV40-transformed fibroblasts, which have different growth rates and different responses to high cell densities, gave different D37 values by this assay in culture trays as compared with colony formation. Comparison of relative sensitivities to irradiation should therefore be made only between cell types with similar growth characteristics. The similar sensitivity of normal and xeroderma pigmentosum cells to mitomycin C was also determined by this culture tray method. By increasing cell density at the beginning of the experiments, a greater capacity of group C compared with group D fibroblasts for recovery from potentially lethal damage was also detected.« less

Comparative evaluation of two rapid Salmonella-IgM tests and blood culture in the diagnosis of enteric fever.

PubMed

Prasad, K J; Oberoi, J K; Goel, N; Wattal, C

2015-01-01

Enteric fever is a major public health problem in developing countries like India. An early and accurate diagnosis is necessary for a prompt and effective treatment. We have evaluated the diagnostic accuracy of two Rapid Salmonella-IgM tests (Typhidot-IgM and Enteroscreen-IgM) as compared to blood culture in rapid and early diagnosis of enteric fever. A total of 2,699 patients' serum samples were tested by Rapid Salmonella-IgM tests and blood culture. Patients were divided into two groups. Test group - patients with enteric fever and blood culture positives for Salmonella Typhi; and three types of Controls, i.e. patients with non-enteric fever illnesses, normal healthy controls and patients positive for S. Paratyphi- A. In addition to this we have also evaluated the significance of positive Salmonella-IgM tests among blood culture-negative cases. The overall sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of the Typhidot-IgM test and Enteroscreen-IgM test considering blood culture as gold standard were 97.29% and 88.13%, 97.40% and 87.83%, 98.18% and 92.03%, 96.15% and 82.27%, respectively. Typhidot-IgM test was found to be significantly more sensitive and specific as compared to Enteroscreen-IgM. Among blood culture-negative patients, Rapid Salmonella-IgM tests detected 72.25% additional cases of enteric fever. Although the Rapid Salmonella-IgM tests are meant to diagnose S. Typhi only, but these tests detect S. Paratyphi- A also. Thirty-eight patients who were blood culture-positive for S. Paratyphi- A were also positive by Rapid Salmonella-IgM tests. Rapid Salmonella-IgM tests offer an advantage of increased sensitivity, rapidity, early diagnosis and simplicity over blood culture.

Multi-colored immunochromatography using nanobeads for rapid and sensitive typing of seasonal influenza viruses.

PubMed

Sakurai, Akira; Takayama, Katsuyoshi; Nomura, Namiko; Yamamoto, Naoki; Sakoda, Yoshihiro; Kobayashi, Yukuharu; Kida, Hiroshi; Shibasaki, Futoshi

2014-12-01

Immunochromatography (IC) is an antigen-detection assay that plays an important role in the rapid diagnosis of influenza viruses because of its rapid turnaround and ease of use. Despite the usefulness of IC, the limit of detection of common IC kits is as high as 10(3)-10(4) plaque forming units (pfu) per reaction, resulting in their limited sensitivities. Early diagnosis within 24h would provide more appropriate timing of treatment. In this study, a multi-colored NanoAct™ bead IC was established to detect seasonal influenza viruses. This method has approximately 10-fold higher sensitivity than that of colloidal gold or colored latex bead IC assays, and does not require specific instruments. More notably, NanoAct™ bead IC can distinguish influenza A and B viruses from clinical samples with a straightforward readout composed of colored lines. Our results will provide new strategies for the diagnosis, treatment, and a chance to survey of influenza viruses in developing countries and in the field research. Copyright © 2014 Elsevier B.V. All rights reserved.

Isothermal strand-displacement polymerase reaction for visual detection of the Southeast Asian-type deletion of α-thalassemia.

PubMed

Yu, Luxin; Wu, Wei; Lie, Puchang; Liu, Yunhua; Zeng, Lingwen

2013-11-01

A rapid and reliable screening test for thalassemia carrier couples is the most effective strategy to decrease the risk of conceiving fetuses with severe thalassemia. We present an approach based on the isothermal strand-displacement polymerase reaction and the use of a lateral flow strip for the visual detection of an α-thalassemia Southeast Asian-type deletion. This assay was used to evaluate 86 clinical samples (72 cases of Southeast Asian-type deletions and 14 cases of other types of thalassemia), and the results obtained were 100% consistent with those obtained using conventional gap-PCR. The approach thus provides a simple, sensitive, rapid, and cost-effective method for the diagnosis of thalassemia genotypes. Copyright © 2013 American Society for Investigative Pathology and the Association for Molecular Pathology. Published by Elsevier Inc. All rights reserved.

Canine parvovirus--a review of epidemiological and diagnostic aspects, with emphasis on type 2c.

PubMed

Decaro, Nicola; Buonavoglia, Canio

2012-02-24

Canine parvovirus type 2 (CPV-2) emerged in late 1970s causing severe epizootics in kennels and dog shelters worldwide. Soon after its emergence, CPV-2 underwent genetic evolution giving rise consecutively to two antigenic variants, CPV-2a and CPV-2b that replaced progressively the original type. In 2000, a new antigenic variant, CPV-2c, was detected in Italy and rapidly spread to several countries. In comparison to the original type CPV-2, the antigenic variants display increased pathogenicity in dogs and extended host range, being able to infect and cause disease in cats. Epidemiological survey indicate that the newest type CPV-2c is becoming prevalent in different geographic regions and is often associated to severe disease in adult dogs and also in dogs that have completed the vaccination protocols. However, the primary cause of failure of CPV vaccination is interference by maternally derived immunity. Diagnosis of CPV infection by traditional methods has been shown to be poorly sensitive, especially in the late stages of infections. New diagnostic approaches based on molecular methods have been developed for sensitive detection of CPV in clinical samples and rapid characterisation of the viral type. Continuous surveillance will help assess whether there is a real need to update currently available vaccines and diagnostic tests. Copyright © 2011 Elsevier B.V. All rights reserved.

Use of rapid-scan EPR to improve detection sensitivity for spin-trapped radicals.

PubMed

Mitchell, Deborah G; Rosen, Gerald M; Tseitlin, Mark; Symmes, Breanna; Eaton, Sandra S; Eaton, Gareth R

2013-07-16

The short lifetime of superoxide and the low rates of formation expected in vivo make detection by standard continuous wave (CW) electron paramagnetic resonance (EPR) challenging. The new rapid-scan EPR method offers improved sensitivity for these types of samples. In rapid-scan EPR, the magnetic field is scanned through resonance in a time that is short relative to electron spin relaxation times, and data are processed to obtain the absorption spectrum. To validate the application of rapid-scan EPR to spin trapping, superoxide was generated by the reaction of xanthine oxidase and hypoxanthine with rates of 0.1-6.0 μM/min and trapped with 5-tert-butoxycarbonyl-5-methyl-1-pyrroline-N-oxide (BMPO). Spin trapping with BMPO to form the BMPO-OOH adduct converts the very short-lived superoxide radical into a more stable spin adduct. There is good agreement between the hyperfine splitting parameters obtained for BMPO-OOH by CW and rapid-scan EPR. For the same signal acquisition time, the signal/noise ratio is >40 times higher for rapid-scan than for CW EPR. Rapid-scan EPR can detect superoxide produced by Enterococcus faecalis at rates that are too low for detection by CW EPR. Copyright © 2013 Biophysical Society. Published by Elsevier Inc. All rights reserved.

Rapid separation on copper powder of total mercury in blood and determination of mercury by flameless atomic absorption spectrometry.

PubMed

Dogan, S; Haerdi, W

1979-01-01

The determination of mercury in blood by flameless atomic absorption spectrometry (FAAS) has been described. Prior to its analysis, the sample was decomposed by combustion and separated on a copper powder micro-column. A special type of cell has been used which gives a better sensitivity compared with the types of cells described in the literature and the method of FAAS analysis has been improved. The sensitivity of 0.1 ng for 1% absorbance was observed and the standard deviation for six determinations at this level was found to be +/- 0.05 ng, for 95% probability.

Multifunctional Nanotechnology-Enabled Sensors for Rapid Capture and Detection of Pathogens.

PubMed

Mustafa, Fatima; Hassan, Rabeay Y A; Andreescu, Silvana

2017-09-15

Nanomaterial-based sensing approaches that incorporate different types of nanoparticles (NPs) and nanostructures in conjunction with natural or synthetic receptors as molecular recognition elements provide opportunities for the design of sensitive and selective assays for rapid detection of contaminants. This review summarizes recent advancements over the past ten years in the development of nanotechnology-enabled sensors and systems for capture and detection of pathogens. The most common types of nanostructures and NPs, their modification with receptor molecules and integration to produce viable sensing systems with biorecognition, amplification and signal readout are discussed. Examples of all-in-one systems that combine multifunctional properties for capture, separation, inactivation and detection are also provided. Current trends in the development of low-cost instrumentation for rapid assessment of food contamination are discussed as well as challenges for practical implementation and directions for future research.

Two distinct classes of functional α7-containing nicotinic receptor on rat superior cervical ganglion neurons

PubMed Central

Cuevas, Javier; Roth, Adelheid L; Berg, Darwin K

2000-01-01

Nicotinic acetylcholine receptors (nAChRs) that bind α-bungarotoxin (αBgt) were studied on isolated rat superior cervical ganglion (SCG) neurons using whole-cell patch clamp recording techniques.Rapid application of ACh onto the soma of voltage clamped neurons evoked a slowly desensitizing current that was reversibly blocked by αBgt (50 nm). The toxin-sensitive current constituted on average about half of the peak whole-cell response evoked by ACh.Nanomolar concentrations of methyllycaconitine blocked the αBgt-sensitive component of the ACh-evoked current as did intracellular dialysis with an anti-α7 monoclonal antibody. The results indicate that the slowly reversible toxin-sensitive response elicited by ACh arises from activation of an unusual class of α7-containing receptor (α7-nAChR) similar to that reported previously for rat intracardiac ganglion neurons.A second class of functional α7-nAChR was identified on some SCG neurons by using rapid application of choline to elicit responses. In these cases a biphasic response was obtained, which included a rapidly desensitizing component that was blocked by αBgt in a pseudo-irreversible manner. The pharmacology and kinetics of the responses resembled those previously attributed to α7-nAChRs in a number of other neuronal cell types.Experiments measuring the dissociation rate of 125I-labelled αBgt from SCG neurons revealed two classes of toxin-binding site. The times for toxin dissociation were consistent with those required to reverse blockade of the two kinds of αBgt-sensitive response.These results indicate that rat SCG neurons express two types of functional α7-nAChR, differing in pharmacology, desensitization and reversibility of αBgt blockade. PMID:10856125

Fluorescence polarization immunoassays for rapid, accurate and sensitive determination of mycotoxins

USDA-ARS?s Scientific Manuscript database

Fluorescence polarization immunoassay (FPIA) is a type of homogeneous assay. For low molecular weight antigens, such as mycotoxins, it is based on the competition between an unlabeled antigen and its fluorescent-labeled derivative (tracer) for an antigen-specific antibody. The antigen content is det...

Genetic variation of pfhrp2 in Plasmodium falciparum isolates from Yemen and the performance of HRP2-based malaria rapid diagnostic test.

PubMed

Atroosh, Wahib M; Al-Mekhlafi, Hesham M; Al-Jasari, Adel; Sady, Hany; Al-Delaimy, Ahmed K; Nasr, Nabil A; Dawaki, Salwa; Abdulsalam, Awatif M; Ithoi, Init; Lau, Yee Ling; Fong, Mun Yik; Surin, Johari

2015-07-22

The genetic variation in the Plasmodium falciparum histidine-rich protein 2 (pfhrp2) gene that may compromise the use of pfhrp2-based rapid diagnostic tests (RDTs) for the diagnosis of malaria was assessed in P. falciparum isolates from Yemen. This study was conducted in Hodeidah and Al-Mahwit governorates, Yemen. A total of 622 individuals with fever were examined for malaria by CareStart malaria HRP2-RDT and Giemsa-stained thin and thick blood films. The Pfhrp2 gene was amplified and sequenced from 180 isolates, and subjected to amino acid repeat types analysis. A total of 188 (30.2%) participants were found positive for P. falciparum by the RDT. Overall, 12 different amino acid repeat types were identified in Yemeni isolates. Six repeat types were detected in all the isolates (100%) namely types 1, 2, 6, 7, 10 and 12 while types 9 and 11 were not detected in any of the isolates. Moreover, the sensitivity and specificity of the used PfHRP2-based RDTs were high (90.5% and 96.1%, respectively). The present study provides data on the genetic variation within the pfhrp2 gene, and its potential impact on the PfHRP2-based RDTs commonly used in Yemen. CareStart Malaria HRP2-based RDT showed high sensitivity and specificity in endemic areas of Yemen.

Development of Isothermal Recombinase Polymerase Amplification Assay for Rapid Detection of Porcine Circovirus Type 2.

PubMed

Yang, Yang; Qin, Xiaodong; Sun, Yingjun; Cong, Guozheng; Li, Yanmin; Zhang, Zhidong

2017-01-01

Porcine circovirus virus type II (PCV2) is the etiology of postweaning multisystemic wasting syndrome (PMWS), porcine dermatitis, nephropathy syndrome (PDNS), and necrotizing pneumonia. Rapid diagnosis tool for detection of PCV2 plays an important role in the disease control and eradication program. Recombinase polymerase amplification (RPA) assays using a real-time fluorescent detection (PCV2 real-time RPA assay) and RPA combined with lateral flow dipstick (PCV2 RPA LFD assay) were developed targeting the PCV2 ORF2 gene. The results showed that the sensitivity of the PCV2 real-time RPA assay was 10 2 copies per reaction within 20 min at 37°C and the PCV2 RPA LFD assay had a detection limit of 10 2 copies per reaction in less than 20 min at 37°C. Both assays were highly specific for PCV2, with no cross-reactions with porcine circovirus virus type 1, foot-and-mouth disease virus, pseudorabies virus, porcine parvovirus, porcine reproductive and respiratory syndrome virus, and classical swine fever virus. Therefore, the RPA assays provide a novel alternative for simple, sensitive, and specific identification of PCV2.

Development of Isothermal Recombinase Polymerase Amplification Assay for Rapid Detection of Porcine Circovirus Type 2

PubMed Central

Yang, Yang; Qin, Xiaodong; Sun, Yingjun; Cong, Guozheng; Li, Yanmin

2017-01-01

Porcine circovirus virus type II (PCV2) is the etiology of postweaning multisystemic wasting syndrome (PMWS), porcine dermatitis, nephropathy syndrome (PDNS), and necrotizing pneumonia. Rapid diagnosis tool for detection of PCV2 plays an important role in the disease control and eradication program. Recombinase polymerase amplification (RPA) assays using a real-time fluorescent detection (PCV2 real-time RPA assay) and RPA combined with lateral flow dipstick (PCV2 RPA LFD assay) were developed targeting the PCV2 ORF2 gene. The results showed that the sensitivity of the PCV2 real-time RPA assay was 102 copies per reaction within 20 min at 37°C and the PCV2 RPA LFD assay had a detection limit of 102 copies per reaction in less than 20 min at 37°C. Both assays were highly specific for PCV2, with no cross-reactions with porcine circovirus virus type 1, foot-and-mouth disease virus, pseudorabies virus, porcine parvovirus, porcine reproductive and respiratory syndrome virus, and classical swine fever virus. Therefore, the RPA assays provide a novel alternative for simple, sensitive, and specific identification of PCV2. PMID:28424790

An insulated isothermal PCR method on a field-deployable device for rapid and sensitive detection of canine parvovirus type 2 at points of need.

PubMed

Wilkes, Rebecca P; Lee, Pei-Yu A; Tsai, Yun-Long; Tsai, Chuan-Fu; Chang, Hsiu-Hui; Chang, Hsiao-Fen G; Wang, Hwa-Tang T

2015-08-01

Canine parvovirus type 2 (CPV-2), including subtypes 2a, 2b and 2c, causes an acute enteric disease in both domestic and wild animals. Rapid and sensitive diagnosis aids effective disease management at points of need (PON). A commercially available, field-deployable and user-friendly system, designed with insulated isothermal PCR (iiPCR) technology, displays excellent sensitivity and specificity for nucleic acid detection. An iiPCR method was developed for on-site detection of all circulating CPV-2 strains. Limit of detection was determined using plasmid DNA. CPV-2a, 2b and 2c strains, a feline panleukopenia virus (FPV) strain, and nine canine pathogens were tested to evaluate assay specificity. Reaction sensitivity and performance were compared with an in-house real-time PCR using serial dilutions of a CPV-2b strain and 100 canine fecal clinical samples collected from 2010 to 2014, respectively. The 95% limit of detection of the iiPCR method was 13 copies of standard DNA and detection limits for CPV-2b DNA were equivalent for iiPCR and real-time PCR. The iiPCR reaction detected CPV-2a, 2b and 2c and FPV. Non-targeted pathogens were not detected. Test results of real-time PCR and iiPCR from 99 fecal samples agreed with each other, while one real-time PCR-positive sample tested negative by iiPCR. Therefore, excellent agreement (k = 0.98) with sensitivity of 98.41% and specificity of 100% in detecting CPV-2 in feces was found between the two methods. In conclusion, the iiPCR system has potential to serve as a useful tool for rapid and accurate PON, molecular detection of CPV-2. Copyright © 2015 The Authors. Published by Elsevier B.V. All rights reserved.

Sensitive, rapid, quantitative and in vitro method for the detection of biologically active staphylococcal enterotoxin type E

USDA-ARS?s Scientific Manuscript database

Staphylococcus aureus is a major bacterial pathogen which causes clinical infections and food poisoning. This bacterium produces a group of enterotoxins (SEs). These enterotoxins have two separate but related biological activities. They cause gastroenteritis and function as superantigens that activa...

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.

Supersensitive detection and discrimination of enantiomers by dorsal olfactory receptors: evidence for hierarchical odour coding.

PubMed

Sato, Takaaki; Kobayakawa, Reiko; Kobayakawa, Ko; Emura, Makoto; Itohara, Shigeyoshi; Kizumi, Miwako; Hamana, Hiroshi; Tsuboi, Akio; Hirono, Junzo

2015-09-11

Enantiomeric pairs of mirror-image molecular structures are difficult to resolve by instrumental analyses. The human olfactory system, however, discriminates (-)-wine lactone from its (+)-form rapidly within seconds. To gain insight into receptor coding of enantiomers, we compared behavioural detection and discrimination thresholds of wild-type mice with those of ΔD mice in which all dorsal olfactory receptors are genetically ablated. Surprisingly, wild-type mice displayed an exquisite "supersensitivity" to enantiomeric pairs of wine lactones and carvones. They were capable of supersensitive discrimination of enantiomers, consistent with their high detection sensitivity. In contrast, ΔD mice showed selective major loss of sensitivity to the (+)-enantiomers. The resulting 10(8)-fold differential sensitivity of ΔD mice to (-)- vs. (+)-wine lactone matched that observed in humans. This suggests that humans lack highly sensitive orthologous dorsal receptors for the (+)-enantiomer, similarly to ΔD mice. Moreover, ΔD mice showed >10(10)-fold reductions in enantiomer discrimination sensitivity compared to wild-type mice. ΔD mice detected one or both of the (-)- and (+)-enantiomers over a wide concentration range, but were unable to discriminate them. This "enantiomer odour discrimination paradox" indicates that the most sensitive dorsal receptors play a critical role in hierarchical odour coding for enantiomer identification.

Supersensitive detection and discrimination of enantiomers by dorsal olfactory receptors: evidence for hierarchical odour coding

PubMed Central

Sato, Takaaki; Kobayakawa, Reiko; Kobayakawa, Ko; Emura, Makoto; Itohara, Shigeyoshi; Kizumi, Miwako; Hamana, Hiroshi; Tsuboi, Akio; Hirono, Junzo

2015-01-01

Enantiomeric pairs of mirror-image molecular structures are difficult to resolve by instrumental analyses. The human olfactory system, however, discriminates (−)-wine lactone from its (+)-form rapidly within seconds. To gain insight into receptor coding of enantiomers, we compared behavioural detection and discrimination thresholds of wild-type mice with those of ΔD mice in which all dorsal olfactory receptors are genetically ablated. Surprisingly, wild-type mice displayed an exquisite “supersensitivity” to enantiomeric pairs of wine lactones and carvones. They were capable of supersensitive discrimination of enantiomers, consistent with their high detection sensitivity. In contrast, ΔD mice showed selective major loss of sensitivity to the (+)-enantiomers. The resulting 108-fold differential sensitivity of ΔD mice to (−)- vs. (+)-wine lactone matched that observed in humans. This suggests that humans lack highly sensitive orthologous dorsal receptors for the (+)-enantiomer, similarly to ΔD mice. Moreover, ΔD mice showed >1010-fold reductions in enantiomer discrimination sensitivity compared to wild-type mice. ΔD mice detected one or both of the (−)- and (+)-enantiomers over a wide concentration range, but were unable to discriminate them. This “enantiomer odour discrimination paradox” indicates that the most sensitive dorsal receptors play a critical role in hierarchical odour coding for enantiomer identification. PMID:26361056

Streptococcus group B typing: comparison of counter-immunoelectrophoresis with the precipitin method.

PubMed

Kubín, V; Jelínková, J; Franêk, J

1977-07-01

The method of counter-immunoelectrophoresis (CIE) was tested for its applicability to group B streptococcus typing. The results obtained were compared with the typing by the ring precipitin test. Identical antigens and identical hyperimmune typing serum batches had been used in both methods. A large majority of 75 freshly isolated strains were typed identically by both methods. Five strains with a weak antigenic outfit were untypable by the ring precipitin test but were typed by CIE owing to a higher sensitivity of CIE method. Two strains were typable by the precipitin test but not by CIE; an explanation for this phenomenon is lacking. The CIE method in group B typing is specific, rapid, highly sensitive and relatively simple. It requires strict maintenance of standard conditions. The method is economical with respect to manipulation and material, requires small amounts of diagnostic antisera. Potent antisera may be used diluted. Moreover, sera for CIE typing need not be absorbed to remove group B antibodies. CIE method is practicable for group B streptococcus typing, especially in laboratories carrying out routine large scale type identification.

Multifunctional Nanotechnology-Enabled Sensors for Rapid Capture and Detection of Pathogens

PubMed Central

Mustafa, Fatima; Andreescu, Silvana

2017-01-01

Nanomaterial-based sensing approaches that incorporate different types of nanoparticles (NPs) and nanostructures in conjunction with natural or synthetic receptors as molecular recognition elements provide opportunities for the design of sensitive and selective assays for rapid detection of contaminants. This review summarizes recent advancements over the past ten years in the development of nanotechnology-enabled sensors and systems for capture and detection of pathogens. The most common types of nanostructures and NPs, their modification with receptor molecules and integration to produce viable sensing systems with biorecognition, amplification and signal readout are discussed. Examples of all-in-one systems that combine multifunctional properties for capture, separation, inactivation and detection are also provided. Current trends in the development of low-cost instrumentation for rapid assessment of food contamination are discussed as well as challenges for practical implementation and directions for future research. PMID:28914769

Rapid Detection of Staphylococcus aureus and Methicillin-Resistant S. aureus (MRSA) in Wound Specimens and Blood Cultures: Multicenter Preclinical Evaluation of the Cepheid Xpert MRSA/SA Skin and Soft Tissue and Blood Culture Assays▿

PubMed Central

Wolk, D. M.; Struelens, M. J.; Pancholi, P.; Davis, T.; Della-Latta, P.; Fuller, D.; Picton, E.; Dickenson, R.; Denis, O.; Johnson, D.; Chapin, K.

2009-01-01

A multicenter preclinical evaluation was conducted to evaluate the performance of two Cepheid Xpert assays for detection of methicillin-resistant Staphylococcus aureus (MRSA) and S. aureus. Sensitivity was 97.1% and 98.3% for MRSA in wound and blood culture specimens, respectively. Sensitivity was 100% for S. aureus from both specimen types. PMID:19144803

Comparison of Three Biochemical Tests for Rapid Detection of Extended-Spectrum-β-Lactamase-Producing Enterobacteriaceae.

PubMed

Poirel, Laurent; Fernández, Javier; Nordmann, Patrice

2016-02-01

Enterobacterial isolates producing clavulanic-inhibited extended-spectrum β-lactamases (ESBLs) are increasingly spreading in the community and are often responsible for nosocomial infections. Rapid biochemical tests have been developed recently for their detection. Three tests, namely, the Rapid ESBL NDP test, the β-Lacta test, and the Rapid ESBL Screen, have been evaluated with a collection of 108 well-characterized strains, including wild-type strains, strains producing ESBLs, overexpressed cephalosporinases, and carbapenemases. The ESBL NDP test and the Rapid ESBL Screen (a copy of the ESBL NDP test) are aimed at detecting ESBL producers, while the β-Lacta test is aimed at detecting not only ESBL producers but also cephalosporinase and carbapenemase producers. The sensitivity and specificity for detecting ESBL producers (n = 60) were 95% and 100% for the Rapid ESBL NDP test, 80% and 87% (after 30 min) and 92% and 83% (after 2 h) for the Rapid ESBL Screen, and 88% and 71% for the β-Lacta test, respectively. Varied and time-consuming detection (up to 2 h) of ESBLs by the Rapid ESBL Screen and concomitant and varied detection of producers of AmpC and several types of carbapenemases correspond to significant shortcomings of using the Rapid Screen ESBL and β-Lacta tests, respectively. Copyright © 2016, American Society for Microbiology. All Rights Reserved.

Rapid and sensitive detection of canine parvovirus type 2 by recombinase polymerase amplification.

PubMed

Wang, Jianchang; Liu, Libing; Li, Ruiwen; Wang, Jinfeng; Fu, Qi; Yuan, Wanzhe

2016-04-01

A novel recombinase polymerase amplification (RPA)-based method for detection of canine parvovirus type 2 (CPV-2) was developed. Sensitivity analysis showed that the detection limit of RPA was 10 copies of CPV-2 genomic DNA. RPA amplified both CPV-2a and -2b DNA but did not amplify the template of other important dog viruses (CCoV, PRV or CDV), demonstrating high specificity. The method was further validated with 57 canine fecal samples. An outstanding advantage of RPA is that it is an isothermal reaction and can be performed in a water bath, making RPA a potential alternative method for CPV-2 detection in resource-limited settings.

Fluorescent-Magnetic-Biotargeting Multifunctional Nanobioprobes for Detecting and Isolating Multiple Types of Tumor Cells

PubMed Central

Song, Er-Qun; Hu, Jun; Wen, Cong-Ying; Tian, Zhi-Quan; Yu, Xu; Zhang, Zhi-Ling; Shi, Yun-Bo; Pang, Dai-Wen

2011-01-01

Fluorescent-magnetic-biotargeting multifunctional nanobioprobes (FMBMNs) have attracted great attention in recent years due to their increasing, important applications in biomedical research, clinical diagnosis, and biomedicine. We have previously developed such nanobioprobes for the detection and isolation of a single kind of tumor cells. Detection and isolation of multiple tumor markers or tumor cells from complex samples sensitively and with high efficiency is critical for the early diagnosis of tumors, especially malignant tumors or cancers, which will improve clinical diagnosis outcomes and help to select effective treatment approaches. Here, we expanded the application of the monoclonal antibody (mAb)-coupled FMBMNs for multiplexed assays. Multiple types of cancer cells, such as leukemia cells and prostate cancer cells, were detected and collected from mixed samples within 25 minutes by using a magnet and an ordinary fluorescence microscope. The capture efficiencies of mAb-coupled FMBMNs for the above mentioned two types of cells were 96% and 97% respectively. Furthermore, by using the mAb-coupled FMBMNs, specific and sensitive detection and rapid separation of a small number of spiked leukemia cells and prostate cancer cells in a large population of cultured normal cells (about 0.01% were tumor cells) were achieved simply and inexpensively without any sample pretreatment before cell analysis. Therefore, mAb-coupled multicolour FMBMNs may be used for very sensitive detection and rapid isolation of multiple cancer cells in biomedical research and medical diagnostics. PMID:21250650

Sensitivity to image recurrence across eye-movement-like image transitions through local serial inhibition in the retina

PubMed Central

Krishnamoorthy, Vidhyasankar; Weick, Michael; Gollisch, Tim

2017-01-01

Standard models of stimulus encoding in the retina postulate that image presentations activate neurons according to the increase of preferred contrast inside the receptive field. During natural vision, however, images do not arrive in isolation, but follow each other rapidly, separated by sudden gaze shifts. We here report that, contrary to standard models, specific ganglion cells in mouse retina are suppressed after a rapid image transition by changes in visual patterns across the transition, but respond with a distinct spike burst when the same pattern reappears. This sensitivity to image recurrence depends on opposing effects of glycinergic and GABAergic inhibition and can be explained by a circuit of local serial inhibition. Rapid image transitions thus trigger a mode of operation that differs from the processing of simpler stimuli and allows the retina to tag particular image parts or to detect transition types that lead to recurring stimulus patterns. DOI: http://dx.doi.org/10.7554/eLife.22431.001 PMID:28230526

A self-pumping lab-on-a-chip for rapid detection of botulinum toxin.

PubMed

Lillehoj, Peter B; Wei, Fang; Ho, Chih-Ming

2010-09-07

A robust poly(dimethylsiloxane) (PDMS) surface treatment was utilized for the development of a self-pumping lab-on-a-chip (LOC) to rapidly detect minute quantities of toxic substances. One such toxin, botulinum neurotoxin (BoNT), is an extremely lethal substance, which has the potential to cause hundreds of thousands of fatalities if as little as a few grams are released into the environment. To prevent such an outcome, a quick (<45 min) and sensitive detection format is needed. We have developed a self-pumping LOC that can sense down to 1 pg of BoNT type A (in a 1 microL sample) within 15 min in an autonomous manner. The key technologies enabling for such a device are a sensitive electrochemical sensor, an optimized fluidic network and a robust hydrophilic PDMS coating, thereby facilitating autonomous delivery of liquid samples for rapid detection. The stability, simplicity and portability of this device make possible for a storable and distributable system for monitoring bioterrorist attacks.

Interdigitated microelectrode based impedance biosensor for detection of salmonella enteritidis in food samples

NASA Astrophysics Data System (ADS)

Kim, G.; Morgan, M.; Hahm, B. K.; Bhunia, A.; Mun, J. H.; Om, A. S.

2008-03-01

Salmonella enteritidis outbreaks continue to occur, and S. enteritidis-related outbreaks from various food sources have increased public awareness of this pathogen. Conventional methods for pathogens detection and identification are labor-intensive and take days to complete. Some immunological rapid assays are developed, but these assays still require prolonged enrichment steps. Recently developed biosensors have shown great potential for the rapid detection of foodborne pathogens. To develop the biosensor, an interdigitated microelectrode (IME) was fabricated by using semiconductor fabrication process. Anti-Salmonella antibodies were immobilized based on avidin-biotin binding on the surface of the IME to form an active sensing layer. To increase the sensitivity of the sensor, three types of sensors that have different electrode gap sizes (2 μm, 5 μm, 10 μm) were fabricated and tested. The impedimetric biosensor could detect 103 CFU/mL of Salmonella in pork meat extract with an incubation time of 5 minutes. This method may provide a simple, rapid and sensitive method to detect foodborne pathogens.

Rapid detection of the Klebsiella pneumoniae carbapenemase (KPC) gene by loop-mediated isothermal amplification (LAMP).

PubMed

Nakano, Ryuichi; Nakano, Akiyo; Ishii, Yoshikazu; Ubagai, Tsuneyuki; Kikuchi-Ueda, Takane; Kikuchi, Hirotoshi; Tansho-Nagakawa, Shigeru; Kamoshida, Go; Mu, Xiaoqin; Ono, Yasuo

2015-03-01

Klebsiella pneumoniae carbapenemases (KPC), which are associated with resistance to carbapenem, have recently spread worldwide and have become a global concern. It is necessary to detect KPC-producing organisms in clinical settings to be able to control the spread of this resistance. We have developed a loop-mediated isothermal amplification (LAMP) method for rapid detection of KPC producers. LAMP primer sets were designed to recognize the homologous regions of blaKPC-2 to blaKPC-17 and could amplify blaKPC rapidly. The specificity and sensitivity of the primers in the LAMP reactions for blaKPC detection were determined. This LAMP assay was able to specifically detect KPC producers at 68 °C, and no cross-reactivity was observed for other types of β-lactamase (class A, B, C, or D) producers. The detection limit for this assay was found to be 10(0) CFU per tube, in 25 min, which was 10-fold more sensitive than a PCR assay for blaKPC detection. Then, the sensitivity of the LAMP reactions for blaKPC detection in human specimens (sputum samples, urine samples, fecal samples and blood samples) was analyzed; it was observed that the LAMP assay had almost the same sensitivity in these samples as when using purified DNA. The LAMP assay is easy to perform and rapid. It may therefore be routinely applied for detection of KPC producers in the clinical laboratory. Copyright © 2014 Japanese Society of Chemotherapy and The Japanese Association for Infectious Diseases. Published by Elsevier Ltd. All rights reserved.

Rapid and accurate detection of KRAS mutations in colorectal cancers using the isothermal-based optical sensor for companion diagnostics

PubMed Central

Koo, Bonhan; Lee, Tae Yoon; Lee, Jeong Hoon; Shin, Yong; Lim, Seok-Byung

2017-01-01

Although KRAS mutational status testing is becoming a companion diagnostic tool for managing patients with colorectal cancer (CRC), there are still several difficulties when analyzing KRAS mutations using the existing assays, particularly with regard to low sensitivity, its time-consuming, and the need for large instruments. We developed a rapid, sensitive, and specific mutation detection assay based on the bio-photonic sensor termed ISAD (isothermal solid-phase amplification/detection), and used it to analyze KRAS gene mutations in human clinical samples. To validate the ISAD-KRAS assay for use in clinical diagnostics, we examined for hotspot KRAS mutations (codon 12 and codon 13) in 70 CRC specimens using PCR and direct sequencing methods. In a serial dilution study, ISAD-KRAS could detect mutations in a sample containing only 1% of the mutant allele in a mixture of wild-type DNA, whereas both PCR and direct sequencing methods could detect mutations in a sample containing approximately 30% of mutant cells. The results of the ISAD-KRAS assay from 70 clinical samples matched those from PCR and direct sequencing, except in 5 cases, wherein ISAD-KRAS could detect mutations that were not detected by PCR and direct sequencing. We also found that the sensitivity and specificity of ISAD-KRAS were 100% within 30 min. The ISAD-KRAS assay provides a rapid, highly sensitive, and label-free method for KRAS mutation testing, and can serve as a robust and near patient testing approach for the rapid detection of patients most likely to respond to anti-EGFR drugs. PMID:29137388

A convenient microbiological assay employing cell-free extracts for the rapid characterization of Gram-negative carbapenemase producers.

PubMed

Marchiaro, Patricia; Ballerini, Viviana; Spalding, Tamara; Cera, Gabriela; Mussi, María A; Morán-Barrio, Jorgelina; Vila, Alejandro J; Viale, Alejandro M; Limansky, Adriana S

2008-08-01

The dissemination of metallo and serine carbapenem-hydrolysing beta-lactamases among Gram-negative nosocomial bacteria represents an acute problem worldwide. Here, we present a rapid and sensitive assay for the characterization of carbapenemase producers to aid in infection control and prevention. The assay involves a rapid disruption of bacterial isolates with silicon dioxide microbeads, followed by the testing in cell-free extracts of hydrolytic activity towards various beta-lactams including two carbapenems (imipenem and meropenem) and a cephalosporin (ceftazidime). A parallel testing of the effects of selective beta-lactamase inhibitors such as EDTA and clavulanic acid allows differentiation of metallo carbapenemases from serine carbapenemases, and also clavulanic-acid-sensitive from -resistant enzymes among the latter. The efficiency of bacterial disruption using silicon dioxide microbeads was identical to that of ultrasonic treatment. The subsequent microbiological assay aimed to evaluate both substrate specificity and inhibitor profile of carbapenem-hydrolysing enzymes present in the extracts and allowed an accurate differentiation of A, B and D types, as judged by the analysis of 24 well-characterized clinical strains that included metallo-beta-lactamase producers (i.e. VIM-, IMP- and SPM-type Pseudomonas producers; an L1 Stenotrophomonas maltophilia producer; and a GOB-18 Elizabethkingia meningoseptica producer) as well as serine carbapenemase producers (i.e. an SME-type Serratia marcescens producer, a GES-2 Pseudomonas aeruginosa producer, Klebsiella pneumoniae and Citrobacter freundii KPC-2 producers and OXA-type Acinetobacter baumannii producers). We have developed a convenient microbiological assay aimed to more accurately and in a short time characterize carbapenem-hydrolysing enzymes produced by Gram-negative bacteria. The assay possesses broad applicability in the clinical setting.

Nanoswitch-linked immunosorbent assay (NLISA) for fast, sensitive, and specific protein detection.

PubMed

Hansen, Clinton H; Yang, Darren; Koussa, Mounir A; Wong, Wesley P

2017-09-26

Protein detection and quantification play critical roles in both basic research and clinical practice. Current detection platforms range from the widely used ELISA to more sophisticated, and more expensive, approaches such as digital ELISA. Despite advances, there remains a need for a method that combines the simplicity and cost-effectiveness of ELISA with the sensitivity and speed of modern approaches in a format suitable for both laboratory and rapid, point-of-care applications. Building on recent developments in DNA structural nanotechnology, we introduce the nanoswitch-linked immunosorbent assay (NLISA), a detection platform based on easily constructed DNA nanodevices that change conformation upon binding to a target protein with the results read out by gel electrophoresis. NLISA is surface-free and includes a kinetic-proofreading step for purification, enabling both enhanced sensitivity and reduced cross-reactivity. We demonstrate femtomolar-level detection of prostate-specific antigen in biological fluids, as well as reduced cross-reactivity between different serotypes of dengue and also between a single-mutation and wild-type protein. NLISA is less expensive, uses less sample volume, is more rapid, and, with no washes, includes fewer hands-on steps than ELISA, while also achieving superior sensitivity. Our approach also has the potential to enable rapid point-of-care assays, as we demonstrate by performing NLISA with an iPad/iPhone camera for imaging.

A rapid method for the detection of foodborne pathogens by extraction of a trace amount of DNA from raw milk based on amino-modified silica-coated magnetic nanoparticles and polymerase chain reaction.

PubMed

Bai, Yalong; Song, Minghui; Cui, Yan; Shi, Chunlei; Wang, Dapeng; Paoli, George C; Shi, Xianming

2013-07-17

A method based on amino-modified silica-coated magnetic nanoparticles (ASMNPs) and polymerase chain reaction (PCR) was developed to rapidly and sensitively detect foodborne pathogens in raw milk. After optimizing parameters such as pH, temperature, and time, a trace amount of genomic DNA of pathogens could be extracted directly from complex matrices such as raw milk using ASMNPs. The magnetically separated complexes of genomic DNA and ASMNPs were directly subjected to single PCR (S-PCR) or multiplex PCR (M-PCR) to detect single or multiple pathogens from raw milk samples. Salmonella Enteritidis (Gram-negative) and Listeria monocytogenes (Gram-positive) were used as model organisms to artificially contaminate raw milk samples. After magnetic separation and S-PCR, the detection sensitivities were 8 CFU mL(-1) and 13 CFU mL(-1) respectively for these two types of pathogens. Furthermore, this method was successfully used to detect multiple pathogens (S. Enteritidis and L. monocytogenes) from artificially contaminated raw milk using M-PCR at sensitivities of 15 CFU mL(-1) and 25 CFU mL(-1), respectively. This method has great potential to rapidly and sensitively detect pathogens in raw milk or other complex food matrices. Copyright © 2013 Elsevier B.V. All rights reserved.

[Value of 3T magnetic resonance dynamic contrast-enhanced and diffusion-weighted imaging in differential diagnosis of musculoskeletal tumors].

PubMed

Qi, Zi-hua; Li, Chuan-fu; Ma, Xiang-xing; Yang, Hui; Jiang, Bao-dong; Zhang, Kai; Yu, De-xin

2012-04-01

To evaluate the value of magnetic resonance dynamic contrast-enhanced (MR-DCE) and magnetic resonance diffusion-weighted imaging (MR-DWI) in the differentiation of benign and malignant musculoskeletal tumors. Sixty-three patients with pathologically confirmed musculoskeletal tumors were examined with MR-DCE and MR-DWI. Using single shot spin echo planar imaging sequence and different b values of 400, 600, 800 and 1000 s/mm(2), we obtained the apparent diffusion coefficient (ADC) of the lesions. ADC values were measured before and after MR-DCE, with a b value of 600 s/mm(2). The 3D fast acquired multiple phase enhanced fast spoiled gradient recalled echo sequence was obtained for multi-slice of the entire lesion. The time-signal intensity curve (TIC), dynamic contrast-enhanced parameters, maximum slope of increase (MSI), positive enhancement integral, signal enhancement ratio, and time to peak (T(peak)) were also recorded. ADC showed no significant difference between benign and malignant tumors when the b value was 400, 600, 800, or 1000 s/mm(2), and it was not significantly different between benign and malignant tumors in both pre-MR-DCE and post-MR-DCE with b value of 600 s/mm(2). TIC were classified into four types type1 showed rapid progression and gradual drainage; type2 showed rapid progression but had no or slight progression; type 3 showed gradual progression; and type 4 had no or slight progression. Most lesions of type1 or type2 were malignant, whereas most lesions of type 3 or type 4 were benign. When using type1 and type 2 as the standards of malignancy, the diagnostic sensitivity and specificity was 87.23% and 50.00%, respectively. The types of TIC showed significant difference between benign and malignant musculoskeletal tumors(χ(2)=17.009,P=0.001). When using MSI 366.62 ± 174.84 as the standard of malignancy, the diagnostic sensitivity and specificity was 86.78% and 78.67%, respectively. When using T(peak)≤70s as the standard of malignancy, the diagnostic sensitivity and specificity was 82.89%and 85.78%, respectively. Positive enhancement integral and signal enhancement ratio showed no significant difference between benign and malignant musculoskeletal tumors. TIC, MSI and T(peak) of MR-DCE are valuable in differentiating benign from malignant musculoskeletal tumors. T(peak) has the highest diagnostic specificity, and TIC has the highest diagnostic sensitivity. The mean ADC value are no significant difference between benign and malignant tumors.

Sensitive genotyping of foodborne-associated human noroviruses and hepatitis A virus using an array-based platform

USDA-ARS?s Scientific Manuscript database

The viral pathogens, human norovirus (NoV) and hepatitis A virus (HAV), are significant contributors of foodborne associated outbreaks. To develop a typing tool for foodborne viruses, a focused, low-density DNA microarray was developed in conjunction with a rapid and high-throughput fluorescent meth...

LIQUID CHROMATOGRAPHIC DETERMINATION OF 5-(METHYLAMINO)-2-PHENYL-4-[3-(TRIFLUROMETHYL) PHENYL]-3-(2H)-FURANONE IN SOIL

EPA Science Inventory

A rapid, sensitive method is described for the determination of 5-(methylamino)-2-phenyl-4-[3-(trifluromethyl)phenyl]-3-(2H)-furanone RE-40885) concentrations in three soil types. he method consists of extraction of soil samples with methanol, filtration, liquid chromatographic s...

Effectiveness of rapid prescreening and 10% rescreening in liquid-based Papanicolaou testing.

PubMed

Currens, Heather S; Nejkauf, Katharine; Wagner, Lynn; Raab, Stephen S

2012-01-01

Although rapid prescreening (RPS) has been shown to be an effective quality control procedure for detecting false-negative conventional Papanicolaou (Pap) tests, RPS has not been widely implemented in the United States. In our laboratory, cytotechnologists performed RPS in 3,567 liquid-based Pap tests: 1,911 SurePath (BD Diagnostics-TriPath, Burlington, NC) preparations that were manually screened and 1,656 ThinPrep Pap tests (Hologic, Bedford, MA) that were imaged using the ThinPrep Imaging System (Hologic). We compared the sensitivity of RPS, 10% rescreening (R-10%), and routine screening (RS). In contrast with previously published findings, we found that RS + RPS did not improve screening sensitivity compared with RS + R-10%. These results support the following hypotheses: (1) Higher baseline RS sensitivity as a result of Pap test diagnoses standardization implemented for quality improvement purposes decreases the performance impact of RPS. (2) R-10% and RPS quality assurance methods detect diagnostic failures caused by different types of cognitive errors.

NMR experiments for the rapid identification of P=O···H-X type hydrogen bonds in nucleic acids.

PubMed

Duchardt-Ferner, Elke; Wöhnert, Jens

2017-10-01

Hydrogen bonds involving the backbone phosphate groups occur with high frequency in functional RNA molecules. They are often found in well-characterized tertiary structural motifs presenting powerful probes for the rapid identification of these motifs for structure elucidation purposes. We have shown recently that stable hydrogen bonds to the phosphate backbone can in principle be detected by relatively simple NMR-experiments, providing the identity of both the donor hydrogen and the acceptor phosphorous within the same experiment (Duchardt-Ferner et al., Angew Chem Int Ed Engl 50:7927-7930, 2011). However, for imino and hydroxyl hydrogen bond donor groups rapidly exchanging with the solvent as well as amino groups broadened by conformational exchange experimental sensitivity is severely hampered by extensive line broadening. Here, we present improved methods for the rapid identification of hydrogen bonds to phosphate groups in nucleic acids by NMR. The introduction of the SOFAST technique into 1 H, 31 P-correlation experiments as well as a BEST-HNP experiment exploiting 3h J N,P rather than 2h J H,P coupling constants enables the rapid and sensitive identification of these hydrogen bonds in RNA. The experiments are applicable for larger RNAs (up to ~ 100-nt), for donor groups influenced by conformational exchange processes such as amino groups and for hydrogen bonds with rather labile hydrogens such as 2'-OH groups as well as for moderate sample concentrations. Interestingly, the size of the through-hydrogen bond scalar coupling constants depends not only on the type of the donor group but also on the structural context. The largest coupling constants were measured for hydrogen bonds involving the imino groups of protonated cytosine nucleotides as donors.

Intrapulmonary receptors in the Tegu lizard: I. Sensitivity to CO2.

PubMed

Feede, M R; Kuhlmann, W D; Scheid, P

1977-02-01

Single unit vagal recordings from intrapulmonary receptors were obtained in decerebrate, paralyzed lizards both during pump ventilation and during unidirectional ventilation on the cannulated, sack-shaped lung. Two types of receptors were identified: (1) CO2-receptors, which increased their discharge frequency as intrapulmonary CO2 concentration decreased but were not sensitive to stretch of the lung. (2) Mechanoreceptors, which rapidly increased discharge frequency when the lung was stretched. These receptors' CO2 sensitivity varied. Lungs of lizards thus appeared to possess both CO2 receptors, which have functional characteristics similar to those in birds, and mechanoreceptors with properties similar to stretch receptors in mammals.

Rapid detection and typing of pathogenic nonpneumophila Legionella spp. isolates using a multiplex real-time PCR assay.

PubMed

Benitez, Alvaro J; Winchell, Jonas M

2016-04-01

We developed a single tube multiplex real-time PCR assay that allows for the rapid detection and typing of 9 nonpneumophila Legionella spp. isolates that are clinically relevant. The multiplex assay is capable of simultaneously detecting and discriminating L. micdadei, L. bozemanii, L. dumoffii, L. longbeachae, L. feeleii, L. anisa, L. parisiensis, L. tucsonensis serogroup (sg) 1 and 3, and L. sainthelensis sg 1 and 2 isolates. Evaluation of the assay with nucleic acid from each of these species derived from both clinical and environmental isolates and typing strains demonstrated 100% sensitivity and 100% specificity when tested against 43 other Legionella spp. Typing of L. anisa, L. parisiensis, and L. tucsonensis sg 1 and 3 isolates was accomplished by developing a real-time PCR assay followed by high-resolution melt (HRM) analysis targeting the ssrA gene. Further typing of L. bozemanii, L. longbeachae, and L. feeleii isolates to the serogroup level was accomplished by developing a real-time PCR assay followed by HRM analysis targeting the mip gene. When used in conjunction with other currently available diagnostic tests, these assays may aid in rapidly identifying specific etiologies associated with Legionella outbreaks, clusters, sporadic cases, and potential environmental sources. Published by Elsevier Inc.

Complex expression and localization of inactivating Kv channels in cultured hippocampal astrocytes.

PubMed

Bekar, Lane K; Loewen, Matthew E; Cao, Kun; Sun, Xianfeng; Leis, Jerome; Wang, Rui; Forsyth, George W; Walz, Wolfgang

2005-03-01

Voltage-gated potassium channels are well established as critical for setting action potential frequency, membrane potential, and neurotransmitter release in neurons. However, their role in the "nonexcitable" glial cell type is yet to be fully understood. We used whole cell current kinetics, pharmacology, immunocytochemistry, and RT-PCR to characterize A-type current in hippocampal astrocyte cultures to better understand its function. Pharmacological analysis suggests that approximately 70, 10, and <5% of total A current is associated with Kv4, Kv3, and Kv1 channels, respectively. In addition, pharmacology and kinetics provide evidence for a significant contribution of KChIP accessory proteins to astrocytic A-channel composition. Localization of the Shaw Kv3.4 channel to astrocytic processes and the Shal Kv4.3 channel to soma suggest that these channels serve a specific function. Given this complex A-type channel expression pattern, we assessed the role of A currents in membrane voltage oscillations in response to current injections. Although TEA-sensitive delayed-rectifying currents are involved in the extent of repolarization, 4-AP-sensitive A currents serve to increase the rate. As in neurons, this effect may enable astrocytes to respond rapidly to high-frequency synaptic events. Our results indicate that hippocampal astrocytes in vitro express multiple A-type Kv channel alpha-subunits with accessory, possibly Ca(2+)-sensitive, cytoplasmic subunits that appear to be specifically localized to subcellular membrane compartments. Function of these channels remains to be determined in a physiological setting. However, this study suggests that they enable astrocytes to respond rapidly with membrane voltage oscillations to high-frequency incoming signals, possibly synchronizing astrocyte function to neuronal activity.

Factors influencing antibiotic prescribing habits and use of sensitivity testing amongst veterinarians in Europe.

PubMed

De Briyne, N; Atkinson, J; Pokludová, L; Borriello, S P; Price, S

2013-11-16

The Heads of Medicines Agencies and the Federation of Veterinarians of Europe undertook a survey to gain a better insight into the decision-making process of veterinarians in Europe when deciding which antibiotics to prescribe. The survey was completed by 3004 practitioners from 25 European countries. Analysis was to the level of different types of practitioner (food producing (FP) animals, companion animals, equines) and country for Belgium, Czech Republic, France, Germany, Spain, Sweden and the UK. Responses indicate no single information source is universally considered critical, though training, published literature and experience were the most important. Factors recorded which most strongly influenced prescribing behaviour were sensitivity tests, own experience, the risk for antibiotic resistance developing and ease of administration. Most practitioners usually take into account responsible use warnings. Antibiotic sensitivity testing is usually performed where a treatment failure has occurred. Significant differences were observed in the frequency of sensitivity testing at the level of types of practitioners and country. The responses indicate a need to improve sensitivity tests and services, with the availability of rapid and cheaper testing being key factors.

Factors influencing antibiotic prescribing habits and use of sensitivity testing amongst veterinarians in Europe

PubMed Central

De Briyne, N.; Atkinson, J.; Pokludová, L.; Borriello, S. P.; Price, S.

2013-01-01

The Heads of Medicines Agencies and the Federation of Veterinarians of Europe undertook a survey to gain a better insight into the decision-making process of veterinarians in Europe when deciding which antibiotics to prescribe. The survey was completed by 3004 practitioners from 25 European countries. Analysis was to the level of different types of practitioner (food producing (FP) animals, companion animals, equines) and country for Belgium, Czech Republic, France, Germany, Spain, Sweden and the UK. Responses indicate no single information source is universally considered critical, though training, published literature and experience were the most important. Factors recorded which most strongly influenced prescribing behaviour were sensitivity tests, own experience, the risk for antibiotic resistance developing and ease of administration. Most practitioners usually take into account responsible use warnings. Antibiotic sensitivity testing is usually performed where a treatment failure has occurred. Significant differences were observed in the frequency of sensitivity testing at the level of types of practitioners and country. The responses indicate a need to improve sensitivity tests and services, with the availability of rapid and cheaper testing being key factors. PMID:24068699

Morphometrics of cellular damage in mice testis receiving X-ray and high-energy particle irradiation

NASA Technical Reports Server (NTRS)

Sapp, Walter J.

1987-01-01

Murine tests were exposed to single, low doses of either X-ray, helium, or argon radiation. Animals were sacrificed seventy-two hours later. Testes were fixed for transmission electron microscopy (TEM) and sectioned at either 60 nm for TEM observation or at 2 micron for counting using routine light microscope methods. Counts of the total population of surviving spermatogonia, including all type A cells, intermediate, and type B cells, were taken from tubule cross sections identified as Stage 6 and Stage 1 according to spermatogonial configuration. The surviving fraction of spermatogonia as compared to control, S/S sub o, was calculated for each dose. For both ions and X-rays, there was a rapid decline in survival at dose levels of .10 to .15 Gy in Stage 6 tubules. This was followed by a more gradual decrease in population. At higher doses, 0.30 Gy for argon and 0.80 Gy for helium and X-rays, the cell survival rates declined rapidly. Pre-leptotene spermatocytes in Stage 1 tubules exhibited a different survival curve indicating the extreme radio-sensitivity of type B spermatogonia. Data verify that the seminiferous tubules are composed of a heterogeneous population of cells with different radio-sensitivities and that these differences are manifested even at very low doses.

Field-Deployable Reverse Transcription-Insulated Isothermal PCR (RT-iiPCR) Assay for Rapid and Sensitive Detection of Foot-and-Mouth Disease Virus.

PubMed

Ambagala, A; Fisher, M; Goolia, M; Nfon, C; Furukawa-Stoffer, T; Ortega Polo, R; Lung, O

2017-10-01

Foot-and-mouth disease (FMD) is a highly contagious viral disease of cloven-hoofed animals, which can decimate the livestock industry and economy of countries previously free of this disease. Rapid detection of foot-and-mouth disease virus (FMDV) is critical to containing an FMD outbreak. Availability of a rapid, highly sensitive and specific, yet simple and field-deployable assay would support local decision-making during an FMDV outbreak. Here we report validation of a novel reverse transcription-insulated isothermal PCR (RT-iiPCR) assay that can be performed on a commercially available, compact and portable POCKIT ™ analyser that automatically analyses data and displays '+' or '-' results. The FMDV RT-iiPCR assay targets the 3D region of the FMDV genome and was capable of detecting 9 copies of in vitro-transcribed RNA standard with 95% confidence. It accurately identified 63 FMDV strains belonging to all seven serotypes and showed no cross-reactivity with viruses causing similar clinical diseases in cloven-hoofed animals. The assay was able to identify FMDV RNA in multiple sample types including oral, nasal and lesion swabs, epithelial tissue suspensions, vesicular and oral fluid samples, even before the appearance of clinical signs. Clinical sensitivity of the assay was comparable or slightly higher than the laboratory-based real-time RT-PCR assay in use. The assay was able to detect FMDV RNA in vesicular fluid samples without nucleic acid extraction. For RNA extraction from more complex sample types, a commercially available taco ™ mini transportable magnetic bead-based, automated extraction system was used. This assay provides a potentially useful field-deployable diagnostic tool for rapid detection of FMDV in an outbreak in FMD-free countries or for routine diagnostics in endemic countries with less structured laboratory systems. © 2016 Her Majesty the Queen in Right of Canada.

Targeting VEGF-B as a novel treatment for insulin resistance and type 2 diabetes.

PubMed

Hagberg, Carolina E; Mehlem, Annika; Falkevall, Annelie; Muhl, Lars; Fam, Barbara C; Ortsäter, Henrik; Scotney, Pierre; Nyqvist, Daniel; Samén, Erik; Lu, Li; Stone-Elander, Sharon; Proietto, Joseph; Andrikopoulos, Sofianos; Sjöholm, Ake; Nash, Andrew; Eriksson, Ulf

2012-10-18

The prevalence of type 2 diabetes is rapidly increasing, with severe socioeconomic impacts. Excess lipid deposition in peripheral tissues impairs insulin sensitivity and glucose uptake, and has been proposed to contribute to the pathology of type 2 diabetes. However, few treatment options exist that directly target ectopic lipid accumulation. Recently it was found that vascular endothelial growth factor B (VEGF-B) controls endothelial uptake and transport of fatty acids in heart and skeletal muscle. Here we show that decreased VEGF-B signalling in rodent models of type 2 diabetes restores insulin sensitivity and improves glucose tolerance. Genetic deletion of Vegfb in diabetic db/db mice prevented ectopic lipid deposition, increased muscle glucose uptake and maintained normoglycaemia. Pharmacological inhibition of VEGF-B signalling by antibody administration to db/db mice enhanced glucose tolerance, preserved pancreatic islet architecture, improved β-cell function and ameliorated dyslipidaemia, key elements of type 2 diabetes and the metabolic syndrome. The potential use of VEGF-B neutralization in type 2 diabetes was further elucidated in rats fed a high-fat diet, in which it normalized insulin sensitivity and increased glucose uptake in skeletal muscle and heart. Our results demonstrate that the vascular endothelium can function as an efficient barrier to excess muscle lipid uptake even under conditions of severe obesity and type 2 diabetes, and that this barrier can be maintained by inhibition of VEGF-B signalling. We propose VEGF-B antagonism as a novel pharmacological approach for type 2 diabetes, targeting the lipid-transport properties of the endothelium to improve muscle insulin sensitivity and glucose disposal.

Rapid detection of rifampin-resistant clinical isolates of Mycobacterium tuberculosis by reverse dot blot hybridization.

PubMed

Guo, Qian; Yu, Yan; Zhu, Yan Ling; Zhao, Xiu Qin; Liu, Zhi Guang; Zhang, Yuan Yuan; Li, Gui Lian; Wei, Jian Hao; Wu, Yi Mou; Wan, Kang Lin

2015-01-01

A PCR-reverse dot blot hybridization (RDBH) assay was developed for rapid detection of rpoB gene mutations in 'hot mutation region' of Mycobacterium tuberculosis (M. tuberculosis). 12 oligonucleotide probes based on the wild-type and mutant genotype rpoB sequences of M. tuberculosis were designed to screen the most frequent wild-type and mutant genotypes for diagnosing RIF resistance. 300 M. tuberculosis clinical isolates were detected by RDBH, conventional drug-susceptibility testing (DST) and DNA sequencing to evaluate the RDBH assay. The sensitivity and specificity of the RDBH assay were 91.2% (165/181) and 98.3% (117/119), respectively, as compared to DST. When compared with DNA sequencing, the accuracy, positive predictive value (PPV) and negative predictive value (NPV) of the RDBH assay were 97.7% (293/300), 98.2% (164/167), and 97.0% (129/133), respectively. Furthermore, the results indicated that the most common mutations were in codons 531 (48.6%), 526 (25.4%), 516 (8.8%), and 511 (6.6%), and the combinative mutation rate was 15 (8.3%). One and two strains of insertion and deletion were found among all strains, respectively. Our findings demonstrate that the RDBH assay is a rapid, simple and sensitive method for diagnosing RIF-resistant tuberculosis. Copyright © 2015 The Editorial Board of Biomedical and Environmental Sciences. Published by China CDC. All rights reserved.

Molecular Diagnostic Testing for Aspergillus

PubMed Central

Powers-Fletcher, Margaret V.

2016-01-01

The direct detection of Aspergillus nucleic acid in clinical specimens has the potential to improve the diagnosis of aspergillosis by offering more rapid and sensitive identification of invasive infections than is possible with traditional techniques, such as culture or histopathology. Molecular tests for Aspergillus have been limited historically by lack of standardization and variable sensitivities and specificities. Recent efforts have been directed at addressing these limitations and optimizing assay performance using a variety of specimen types. This review provides a summary of standardization efforts and outlines the complexities of molecular testing for Aspergillus in clinical mycology. PMID:27487954

Self-Powered High-Resolution and Pressure-Sensitive Triboelectric Sensor Matrix for Real-Time Tactile Mapping.

PubMed

Wang, Xiandi; Zhang, Hanlu; Dong, Lin; Han, Xun; Du, Weiming; Zhai, Junyi; Pan, Caofeng; Wang, Zhong Lin

2016-04-20

A triboelectric sensor matrix (TESM) can accurately track and map 2D tactile sensing. A self-powered, high-resolution, pressure-sensitive, flexible and durable TESM with 16 × 16 pixels is fabricated for the fast detection of single-point and multi-point touching. Using cross-locating technology, a cross-type TESM with 32 × 20 pixels is developed for more rapid tactile mapping, which significantly reduces the addressing lines from m × n to m + n. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Direct typing of Canine parvovirus (CPV) from infected dog faeces by rapid mini sequencing technique.

PubMed

V, Pavana Jyothi; S, Akila; Selvan, Malini K; Naidu, Hariprasad; Raghunathan, Shwethaa; Kota, Sathish; Sundaram, R C Raja; Rana, Samir Kumar; Raj, G Dhinakar; Srinivasan, V A; Mohana Subramanian, B

2016-12-01

Canine parvovirus (CPV) is a non-enveloped single stranded DNA virus with an icosahedral capsid. Mini-sequencing based CPV typing was developed earlier to detect and differentiate all the CPV types and FPV in a single reaction. This technique was further evaluated in the present study by performing the mini-sequencing directly from fecal samples which avoided tedious virus isolation steps by cell culture system. Fecal swab samples were collected from 84 dogs with enteritis symptoms, suggestive of parvoviral infection from different locations across India. Seventy six of these samples were positive by PCR; the subsequent mini-sequencing reaction typed 74 of them as type 2a virus, and 2 samples as type 2b. Additionally, 25 of the positive samples were typed by cycle sequencing of PCR products. Direct CPV typing from fecal samples using mini-sequencing showed 100% correlation with CPV typing by cycle sequencing. Moreover, CPV typing was achieved by mini-sequencing even with faintly positive PCR amplicons which was not possible by cycle sequencing. Therefore, the mini-sequencing technique is recommended for regular epidemiological follow up of CPV types, since the technique is rapid, highly sensitive and high capacity method for CPV typing. Copyright © 2016. Published by Elsevier B.V.

Evaluation of a nested-PCR for mycobacterium tuberculosis detection in blood and urine samples.

PubMed

da Cruz, Heidi Lacerda Alves; de Albuquerque Montenegro, Rosana; de Araújo Lima, Juliana Falcão; da Rocha Poroca, Diogo; da Costa Lima, Juliana Figueirêdo; Maria Lapa Montenegro, Lílian; Crovella, Sergio; Charifker Schindler, Haiana

2011-01-01

The polymerase chain reaction (PCR) and its variations, such as the nested-PCR, have been described as promising techniques for rapid diagnosis of tuberculosis (TB). With the aim of evaluating the usefulness of a nested-PCR method on samples of blood and urine of patients suspected of tuberculosis we analyzed 192 clinical samples, using as a molecular target the insertion element IS6110 specific of M. tuberculosis genome. Nested-PCR method showed higher sensitivity in patients with extrapulmonary tuberculosis (47.8% and 52% in blood and urine) when compared to patients with the pulmonary form of the disease (sensitivity of 29% and 26.9% in blood and urine), regardless of the type of biological sample used. The nested-PCR is a rapid technique that, even if not showing a good sensitivity, should be considered as a helpful tool especially in the extrapulmonary cases or in cases where confirmatory diagnosis is quite difficult to be achieved by routine methods. The performance of PCR-based techniques should be considered and tested in future works on other types of biological specimens besides sputum, like blood and urine, readily obtainable in most cases. The improving of M. tuberculosis nested-PCR detection in TB affected patients will give the possibility of an earlier detection of bacilli thus interrupting the transmission chain of the disease.

Potential for local and systemic bacterial infection in some occupational groups in Benin City, Nigeria.

PubMed

Hugbo, P G; Okonkwo, J O

1992-06-01

Many Third World countries may not have adequate facilities for rapid sensitivity testing of antibiotics as an aid to diagnosis and chemotherapy. It may therefore be valuable to relate bacterial carriage on the skin to type of work a person does. Given areas of skin in workers from 10 occupational groups were sampled. The bacteria obtained were analyzed after growth on appropriate media. The sensitivity profiles of potential pathogens isolated from these groups, as well as of those (Staphylococcus aureus only) isolated from patients with certified infections, were carried out and the results were analyzed. Staphylococcus aureus constituted the most widely and frequently isolated potential pathogen. Proteus mirabilis, Escherichia coli, and Klebsiella species were also frequent colonizers of skin. There was a statistical relationship between work type and overall prevalence of bacteria on skin (p less than 0.01). Most isolates of the work groups were highly sensitive to gentamicin and cefuroxine but not to penicillin G, ampicillin, and trimethoprim plus sulfamethoxazole; isolates from infected persons were generally more resistant than were the community-acquired ones. A relationship may exist between the types of bacteria carried on the skin and the type of work in which a person is engaged.

Rapid and Sensitive Detection of Brain-Derived Neurotrophic Factor with a Plasmonic Chip

NASA Astrophysics Data System (ADS)

Tawa, Keiko; Satoh, Mari; Uegaki, Koichi; Hara, Tomoko; Kojima, Masami; Kumanogoh, Haruko; Aota, Hiroyuki; Yokota, Yoshiki; Nakaoki, Takahiko; Umetsu, Mitsuo; Nakazawa, Hikaru; Kumagai, Izumi

2013-06-01

Plasmonic chips, which are grating replicas coated with thin metal layers and overlayers such as ZnO, were applied in immunosensors to improve their detection sensitivity. Fluorescence from labeled antibodies bound to plasmonic chips can be enhanced on the basis of a grating-coupled surface plasmon resonance (GC-SPR) field. In this study, as one of the representative candidate protein markers for brain disorders, the brain-derived neurotrophic factor (BDNF) was quantitatively measured by sandwich assay on a plasmonic chip and detected on our plasmonic chip in the concentration of 5-7 ng/mL within 40 min. Furthermore, BDNF was detected in the blood sera from three types of mice: wild-type mice and two types of mutant mice. This technique is promising as a new clinical diagnosis tool for brain disorders based on scientific evidence such as blood test results.

FlyMAD: rapid thermogenetic control of neuronal activity in freely walking Drosophila.

PubMed

Bath, Daniel E; Stowers, John R; Hörmann, Dorothea; Poehlmann, Andreas; Dickson, Barry J; Straw, Andrew D

2014-07-01

Rapidly and selectively modulating the activity of defined neurons in unrestrained animals is a powerful approach in investigating the circuit mechanisms that shape behavior. In Drosophila melanogaster, temperature-sensitive silencers and activators are widely used to control the activities of genetically defined neuronal cell types. A limitation of these thermogenetic approaches, however, has been their poor temporal resolution. Here we introduce FlyMAD (the fly mind-altering device), which allows thermogenetic silencing or activation within seconds or even fractions of a second. Using computer vision, FlyMAD targets an infrared laser to freely walking flies. As a proof of principle, we demonstrated the rapid silencing and activation of neurons involved in locomotion, vision and courtship. The spatial resolution of the focused beam enabled preferential targeting of neurons in the brain or ventral nerve cord. Moreover, the high temporal resolution of FlyMAD allowed us to discover distinct timing relationships for two neuronal cell types previously linked to courtship song.

Rapid method for the determination of 14 isoflavones in food using UHPLC coupled to photo diode array detection.

PubMed

Shim, You-Shin; Yoon, Won-Jin; Hwang, Jin-Bong; Park, Hyun-Jin; Seo, Dongwon; Ha, Jaeho

2015-11-15

A rapid method for the determination of 14 types of isoflavones in food using ultra-high performance liquid chromatography (UHPLC) was validated in terms of precision, accuracy, sensitivity and linearity. The UHPLC separation was performed on a reverse-phase C18 column (particle size 2 μm, i.d. 2 mm, length 100 mm) using a photo diode array detector that was fixed to 260 nm. The limits of detection and quantification of the UHPLC analyses ranged from 0.03 to 0.33 mg kg(-1). The intra-day and inter-day precision of the individual isoflavones were less than 11.77% and calibration curves exhibited good linearity (r(2) = 0.99) within the tested ranges. These results suggest that the rapid method used in this study could be available to determine of 14 types of isoflavones in a variety of food such as soy bean, black bean, red bean and soybean paste. Copyright © 2015 Elsevier Ltd. All rights reserved.

Quantitative determination for cytotoxic Friedo-nor-oleanane derivatives from five morphological types of Maytenus ilicifolia (Celastraceae) by reverse-phase high-performance liquid chromatography.

PubMed

Buffa Filho, Waldemar; Corsino, Joaquim; Bolzani, da Silva Vanderlan; Furlan, Maysa; Pereira, Ana Maria S; França, Suzelei Castro

2002-01-01

Five different morphological types of Maytenus ilicifolia of the same age and harvested under the same conditions showed distinct accumulations of some friedo-nor-oleananes. A rapid, sensitive and reliable reverse-phase HPLC method (employing an external standard) was used for the determination of the cytotoxic triterpenoids, 20 alpha-hydroxymaytenin, 22 beta-hydroxymaytenin, maytenin, celastrol and pristimerin in each of the five types. Well resolved peaks with good detection response and linearity in the range 1.0-100 micrograms/mL were obtained.

Methicillin-Resistant Staphylococcus aureus (MRSA) Detection: Comparison of Two Molecular Methods (IDI-MRSA PCR Assay and GenoType MRSA Direct PCR Assay) with Three Selective MRSA Agars (MRSA ID, MRSASelect, and CHROMagar MRSA) for Use with Infection-Control Swabs▿

PubMed Central

van Hal, S. J.; Stark, D.; Lockwood, B.; Marriott, D.; Harkness, J.

2007-01-01

Methicillin-resistant Staphylococcus aureus (MRSA) is an increasing problem. Rapid detection of MRSA-colonized patients has the potential to limit spread of the organism. We evaluated the sensitivities and specificities of MRSA detection by two molecular methods (IDI-MRSA PCR assay and GenoType MRSA Direct PCR assay) and three selective MRSA agars (MRSA ID, MRSASelect, and CHROMagar MRSA), using 205 (101 nasal, 52 groin, and 52 axillary samples) samples from consecutive known MRSA-infected and/or -colonized patients. All detection methods had higher MRSA detection rates for nasal swabs than for axillary and groin swabs. Detection of MRSA by IDI-MRSA was the most sensitive method, independent of the site (94% for nasal samples, 80% for nonnasal samples, and 90% overall). The sensitivities of the GenoType MRSA Direct assay and the MRSA ID, MRSASelect, and CHROMagar MRSA agars with nasal swabs were 70%, 72%, 68%, and 75%, respectively. All detection methods had high specificities (95 to 99%), independent of the swab site. Extended incubation for a further 24 h with selective MRSA agars increased the detection of MRSA, with a corresponding decline in specificity secondary to a significant increase in false-positive results. There was a noticeable difference in test performance of the GenoType MRSA Direct assay in detection of MRSA (28/38 samples [74%]) compared with detection of nonmultiresistant MRSA (17/31 samples [55%]) (susceptible to two or more non-β-lactam antibiotics). This was not observed with selective MRSA agar plates or IDI-MRSA. Although it is more expensive, in addition to rapid turnaround times of 2 to 4 h, IDI-MRSA offers greater detection of MRSA colonization, independent of the swab site, than do conventional selective agars and GenoType MRSA Direct. PMID:17537949

Rapid pH change due to bacteriorhodopsin measured with a tin-oxide electrode.

PubMed Central

Robertson, B; Lukashev, E P

1995-01-01

The photocurrent transient generated by bacteriorhodopsin (bR) on a tin-oxide electrode is due to pH change and not to charge displacement as previously assumed. Films of either randomly oriented or highly oriented purple membranes were deposited on transparent electrodes made of tin-oxide-coated glass. The membranes contained either wild-type or D96N-mutant bR. When excited with yellow light through the glass, the bR pumps protons across the membrane. The result is a rapid local pH change as well as a charge displacement. Experiments with these films show that it is the pH change rather than the displacement that produces the current transient. The calibration for the transient pH measurement is given. The sensitivity of a tin-oxide electrode to a transient pH change is very much larger than its sensitivity to a steady-state pH change. PMID:7787036

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.

Treating Type 1 Diabetes Mellitus with a Rapid-Acting Analog Insulin Regimen vs. Regular Human Insulin in Germany: A Long-Term Cost-Effectiveness Evaluation.

PubMed

Valentine, William J; Van Brunt, Kate; Boye, Kristina S; Pollock, Richard F

2018-06-01

The aim of the present study was to evaluate the cost effectiveness of rapid-acting analog insulin relative to regular human insulin in adults with type 1 diabetes mellitus in Germany. The PRIME Diabetes Model, a patient-level, discrete event simulation model, was used to project long-term clinical and cost outcomes for patients with type 1 diabetes from the perspective of a German healthcare payer. Simulated patients had a mean age of 21.5 years, duration of diabetes of 8.6 years, and baseline glycosylated hemoglobin of 7.39%. Regular human insulin and rapid-acting analog insulin regimens reduced glycosylated hemoglobin by 0.312 and 0.402%, respectively. Compared with human insulin, hypoglycemia rate ratios with rapid-acting analog insulin were 0.51 (non-severe nocturnal) and 0.80 (severe). No differences in non-severe diurnal hypoglycemia were modeled. Discount rates of 3% were applied to future costs and clinical benefits accrued over the 50-year time horizon. In the base-case analysis, rapid-acting analog insulin was associated with an improvement in quality-adjusted life expectancy of 1.01 quality-adjusted life-years per patient (12.54 vs. 11.53 quality-adjusted life-years). Rapid-acting analog insulin was also associated with an increase in direct costs of €4490, resulting in an incremental cost-effectiveness ratio of €4427 per quality-adjusted life-year gained vs. human insulin. Sensitivity analyses showed that the base case was driven predominantly by differences in hypoglycemia; abolishing these differences reduced incremental quality-adjusted life expectancy to 0.07 quality-adjusted life-years, yielding an incremental cost-effectiveness ratio of €74,622 per quality-adjusted life-year gained. Rapid-acting analog insulin is associated with beneficial outcomes in patients with type 1 diabetes and is likely to be considered cost effective in the German setting vs. regular human insulin.

The Arabidopsis aba4-1 mutant reveals a specific function for neoxanthin in protection against photooxidative stress.

PubMed

Dall'Osto, Luca; Cazzaniga, Stefano; North, Helen; Marion-Poll, Annie; Bassi, Roberto

2007-03-01

The aba4-1 mutant completely lacks neoxanthin but retains all other xanthophyll species. The missing neoxanthin in light-harvesting complex (Lhc) proteins is compensated for by higher levels of violaxanthin, albeit with lower capacity for photoprotection compared with proteins with wild-type levels of neoxanthin. Detached leaves of aba4-1 were more sensitive to oxidative stress than the wild type when exposed to high light and incubated in a solution of photosensitizer agents. Both treatments caused more rapid pigment bleaching and lipid oxidation in aba4-1 than wild-type plants, suggesting that neoxanthin acts as an antioxidant within the photosystem II (PSII) supercomplex in thylakoids. While neoxanthin-depleted Lhc proteins and leaves had similar sensitivity as the wild type to hydrogen peroxide and singlet oxygen, they were more sensitive to superoxide anions. aba4-1 intact plants were not more sensitive than the wild type to high-light stress, indicating the existence of compensatory mechanisms of photoprotection involving the accumulation of zeaxanthin. However, the aba4-1 npq1 double mutant, lacking zeaxanthin and neoxanthin, underwent stronger PSII photoinhibition and more extensive oxidation of pigments than the npq1 mutant, which still contains neoxanthin. We conclude that neoxanthin preserves PSII from photoinactivation and protects membrane lipids from photooxidation by reactive oxygen species. Neoxanthin appears particularly active against superoxide anions produced by the Mehler's reaction, whose rate is known to be enhanced in abiotic stress conditions.

The Arabidopsis aba4-1 Mutant Reveals a Specific Function for Neoxanthin in Protection against Photooxidative Stress[W

PubMed Central

Dall'Osto, Luca; Cazzaniga, Stefano; North, Helen; Marion-Poll, Annie; Bassi, Roberto

2007-01-01

The aba4-1 mutant completely lacks neoxanthin but retains all other xanthophyll species. The missing neoxanthin in light-harvesting complex (Lhc) proteins is compensated for by higher levels of violaxanthin, albeit with lower capacity for photoprotection compared with proteins with wild-type levels of neoxanthin. Detached leaves of aba4-1 were more sensitive to oxidative stress than the wild type when exposed to high light and incubated in a solution of photosensitizer agents. Both treatments caused more rapid pigment bleaching and lipid oxidation in aba4-1 than wild-type plants, suggesting that neoxanthin acts as an antioxidant within the photosystem II (PSII) supercomplex in thylakoids. While neoxanthin-depleted Lhc proteins and leaves had similar sensitivity as the wild type to hydrogen peroxide and singlet oxygen, they were more sensitive to superoxide anions. aba4-1 intact plants were not more sensitive than the wild type to high-light stress, indicating the existence of compensatory mechanisms of photoprotection involving the accumulation of zeaxanthin. However, the aba4-1 npq1 double mutant, lacking zeaxanthin and neoxanthin, underwent stronger PSII photoinhibition and more extensive oxidation of pigments than the npq1 mutant, which still contains neoxanthin. We conclude that neoxanthin preserves PSII from photoinactivation and protects membrane lipids from photooxidation by reactive oxygen species. Neoxanthin appears particularly active against superoxide anions produced by the Mehler's reaction, whose rate is known to be enhanced in abiotic stress conditions. PMID:17351115

Assessing geomorphic sensitivity in relation to river capacity for adjustment

NASA Astrophysics Data System (ADS)

Reid, H. E.; Brierley, G. J.

2015-12-01

River sensitivity describes the nature and rate of channel adjustments. An approach to analysis of geomorphic river sensitivity outlined in this paper relates potential sensitivity based on the expected capacity of adjustment for a river type to the recent history of channel adjustment. This approach was trialled to assess low, moderate and high geomorphic sensitivity for four different types of river (10 reaches in total) along the Lower Tongariro River, North Island, New Zealand. Building upon the River Styles framework, river types were differentiated based upon valley setting (width and confinement), channel planform, geomorphic unit assemblages and bed material size. From this, the behavioural regime and potential for adjustment (type and extent) were determined. Historical maps and aerial photographs were geo-rectified and the channel planform digitised to assess channel adjustments for each reach from 1928 to 2007. Floodplain width controlled by terraces, exerted a strong influence upon reach scale sensitivity for the partly-confined, wandering, cobble-bed river. Although forced boundaries occur infrequently, the width of the active channel zone is constrained. An unconfined braided river reach directly downstream of the terrace-confined section was the most geomorphically sensitive reach. The channel in this reach adjusted recurrently to sediment inputs that were flushed through more confined, better connected upstream reaches. A meandering, sand-bed river in downstream reaches has exhibited negligible rates of channel migration. However, channel narrowing in this reach and the associated delta indicate that the system is approaching a threshold condition, beyond which channel avulsion is likely to occur. As this would trigger more rapid migration, this reach is considered to be more geomorphically sensitive than analysis of its low migration rate alone would indicate. This demonstrates how sensitivity is fashioned both by the behavioural regime of a reach and flow/sediment input from upstream. The approach to assess geomorphic river sensitivity outlined here could support 'room to move' or 'freedom space' approaches to river management by relating likely channel adjustments for the type of river under consideration to the area of land that is required to contain 'natural' patterns and rates of geomorphic functionality.

Rapid diagnostic tests for diagnosing uncomplicated non-falciparum or Plasmodium vivax malaria in endemic countries

PubMed Central

Abba, Katharine; Kirkham, Amanda J; Olliaro, Piero L; Deeks, Jonathan J; Donegan, Sarah; Garner, Paul; Takwoingi, Yemisi

2014-01-01

Background In settings where both Plasmodium vivax and Plasmodium falciparum infection cause malaria, rapid diagnostic tests (RDTs) need to distinguish which species is causing the patients' symptoms, as different treatments are required. Older RDTs incorporated two test lines to distinguish malaria due to P. falciparum, from malaria due to any other Plasmodium species (non-falciparum). These RDTs can be classified according to which antibodies they use: Type 2 RDTs use HRP-2 (for P. falciparum) and aldolase (all species); Type 3 RDTs use HRP-2 (for P. falciparum) and pLDH (all species); Type 4 use pLDH (fromP. falciparum) and pLDH (all species). More recently, RDTs have been developed to distinguish P. vivax parasitaemia by utilizing a pLDH antibody specific to P. vivax. Objectives To assess the diagnostic accuracy of RDTs for detecting non-falciparum or P. vivax parasitaemia in people living in malaria-endemic areas who present to ambulatory healthcare facilities with symptoms suggestive of malaria, and to identify which types and brands of commercial test best detect non-falciparum and P. vivax malaria. Search methods We undertook a comprehensive search of the following databases up to 31 December 2013: Cochrane Infectious Diseases Group Specialized Register; MEDLINE; EMBASE; MEDION; Science Citation Index; Web of Knowledge; African Index Medicus; LILACS; and IndMED. Selection criteria Studies comparing RDTs with a reference standard (microscopy or polymerase chain reaction) in blood samples from a random or consecutive series of patients attending ambulatory health facilities with symptoms suggestive of malaria in non-falciparum endemic areas. Data collection and analysis For each study, two review authors independently extracted a standard set of data using a tailored data extraction form. We grouped comparisons by type of RDT (defined by the combinations of antibodies used), and combined in meta-analysis where appropriate. Average sensitivities and specificities are presented alongside 95% confidence intervals (95% CI). Main results We included 47 studies enrolling 22,862 participants. Patient characteristics, sampling methods and reference standard methods were poorly reported in most studies. RDTs detecting 'non-falciparum' parasitaemia Eleven studies evaluated Type 2 tests compared with microscopy, 25 evaluated Type 3 tests, and 11 evaluated Type 4 tests. In meta-analyses, average sensitivities and specificities were 78% (95% CI 73% to 82%) and 99% (95% CI 97% to 99%) for Type 2 tests, 78% (95% CI 69% to 84%) and 99% (95% CI 98% to 99%) for Type 3 tests, and 89% (95% CI 79% to 95%) and 98% (95% CI 97% to 99%) for Type 4 tests, respectively. Type 4 tests were more sensitive than both Type 2 (P = 0.01) and Type 3 tests (P = 0.03). Five studies compared Type 3 tests with PCR; in meta-analysis, the average sensitivity and specificity were 81% (95% CI 72% to 88%) and 99% (95% CI 97% to 99%) respectively. RDTs detecting P.vivax parasitaemia Eight studies compared pLDH tests to microscopy; the average sensitivity and specificity were 95% (95% CI 86% to 99%) and 99% (95% CI 99% to 100%), respectively. Authors' conclusions RDTs designed to detect P. vivax specifically, whether alone or as part of a mixed infection, appear to be more accurate than older tests designed to distinguish P. falciparum malaria from non-falciparum malaria. Compared to microscopy, these tests fail to detect around 5% ofP. vivax cases. This Cochrane Review, in combination with other published information about in vitro test performance and stability in the field, can assist policy-makers to choose between the available RDTs. PLAIN LANGUAGE SUMMARY Rapid tests for diagnosing malaria caused by Plasmodium vivax or other less common parasites This review summarises trials evaluating the accuracy of rapid diagnostic tests (RDTs) for diagnosing malaria due to Plasmodium vivax or other non-falciparum species. After searching for relevant studies up to December 2013, we included 47 studies, enrolling 22,862 adults and children. What are rapid tests and why do they need to be able to distinguish Plasmodium vivax malaria RDTs are simple to use, point of care tests, suitable for use in rural settings by primary healthcare workers. RDTs work by using antibodies to detect malaria antigens in the patient's blood. A drop of blood is placed on the test strip where the antibodies and antigen combine to create a distinct line indicating a positive test. Malaria can be caused any one of five species of Plasmodium parasite, but P. falciparum and P. vivax are the most common. In some areas, RDTs need to be able to distinguish which species is causing the malaria symptoms as different species may require different treatments. Unlike P. falciparum, P. vivax has a liver stage which can cause repeated illness every few months unless it is treated with primaquine. The most common types of RDTs for P. vivax use two test lines in combination; one line specific to P. falciparum, and one line which can detect any species of Plasmodium. If the P. falciparum line is negative and the 'any species' line is positive, the illness is presumed to be due to P. vivax (but could also be caused by P. malariae, or P. ovale). More recently, RDTs have been developed which specifically test for P. vivax. What does the research say RDTs testing for non-falciparum malaria were very specific (range 98% to 100%) meaning that only 1% to 2% of patients who test positive would actually not have the disease. However, they were less sensitive (range 78% to 89%), meaning between 11% and 22% of people with non-falciparum malaria would actually get a negative test result. RDTs which specifically tested for P. vivax were more accurate with a specificity of 99% and a sensitivity of 95%, meaning that only 5% of people with P. vivax malaria would have a negative test result. PMID:25519857

In vitro detection and quantification of botulinum neurotoxin type E activity in avian blood

USGS Publications Warehouse

Piazza, T.M.; Blehert, D.S.; Dunning, F.M.; Berlowski-Zier, B. M.; Zeytin, F.N.; Samuel, M.D.; Tucker, W.C.

2011-01-01

Botulinum neurotoxin serotype E (BoNT/E) outbreaks in the Great Lakes region cause large annual avian mortality events, with an estimated 17,000 bird deaths reported in 2007 alone. During an outbreak investigation, blood collected from bird carcasses is tested for the presence of BoNT/E using the mouse lethality assay. While sensitive, this method is labor-intensive and low throughput and can take up to 7 days to complete. We developed a rapid and sensitive in vitro assay, the BoTest Matrix E assay, that combines immunoprecipitation with high-affinity endopeptidase activity detection by F??rster resonance energy transfer (FRET) to rapidly quantify BoNT/E activity in avian blood with detection limits comparable to those of the mouse lethality assay. On the basis of the analysis of archived blood samples (n = 87) collected from bird carcasses during avian mortality investigations, BoTest Matrix E detected picomolar quantities of BoNT/E following a 2-h incubation and femtomolar quantities of BoNT/E following extended incubation (24 h) with 100% diagnostic specificity and 91% diagnostic sensitivity. ?? 2011, American Society for Microbiology.

Biomarkers of exposure and dose: state of the art.

PubMed

Brooks, A L

2001-01-01

Biomarkers provide methods to measure changes in biological systems and to relate them to environmental insults and disease processes. Biomarkers can be classified as markers of exposure and dose, markers of sensitivity, and markers of disease. It is important that the differences and applications of the various types of biomarkers be clearly understood. The military is primarily interested in early biomarkers of exposure and dose that do not require high levels of sensitivity but can be used to rapidly triage war fighters under combat or terrorist conditions and determine which, if any, require medical attention. Biomarkers of long-term radiation risk represent the second area of interest for the military. Biomarkers of risk require high sensitivity and specificity for the disease and insult but do not require rapid data turnaround. Biomarkers will help provide information for quick command decisions in the field, characterise long-term troop risks and identify early stages of radiation-induced diseases. This information provides major positive reassurances about individual exposures and risk that will minimise the physical and psychological impact of wartime radiation exposures.

In vitro detection and quantification of botulinum neurotoxin type E activity in avian blood

USGS Publications Warehouse

Piazza, Timothy M.; Blehert, David S.; Dunning, F. Mark; Berlowski-Zier, Brenda M.; Zeytin, Fusun N.; Samuel, Michael D.; Tucker, Ward C.

2011-01-01

Botulinum neurotoxin serotype E (BoNT/E) outbreaks in the Great Lakes region cause large annual avian mortality events, with an estimated 17,000 bird deaths reported in 2007 alone. During an outbreak investigation, blood collected from bird carcasses is tested for the presence of BoNT/E using the mouse lethality assay. While sensitive, this method is labor-intensive and low throughput and can take up to 7 days to complete. We developed a rapid and sensitive in vitro assay, the BoTest Matrix E assay, that combines immunoprecipitation with high-affinity endopeptidase activity detection by Förster resonance energy transfer (FRET) to rapidly quantify BoNT/E activity in avian blood with detection limits comparable to those of the mouse lethality assay. On the basis of the analysis of archived blood samples (n = 87) collected from bird carcasses during avian mortality investigations, BoTest Matrix E detected picomolar quantities of BoNT/E following a 2-h incubation and femtomolar quantities of BoNT/E following extended incubation (24 h) with 100% diagnostic specificity and 91% diagnostic sensitivity.

In Vitro Detection and Quantification of Botulinum Neurotoxin Type E Activity in Avian Blood▿

PubMed Central

Piazza, Timothy M.; Blehert, David S.; Dunning, F. Mark; Berlowski-Zier, Brenda M.; Zeytin, Füsûn N.; Samuel, Michael D.; Tucker, Ward C.

2011-01-01

Botulinum neurotoxin serotype E (BoNT/E) outbreaks in the Great Lakes region cause large annual avian mortality events, with an estimated 17,000 bird deaths reported in 2007 alone. During an outbreak investigation, blood collected from bird carcasses is tested for the presence of BoNT/E using the mouse lethality assay. While sensitive, this method is labor-intensive and low throughput and can take up to 7 days to complete. We developed a rapid and sensitive in vitro assay, the BoTest Matrix E assay, that combines immunoprecipitation with high-affinity endopeptidase activity detection by Förster resonance energy transfer (FRET) to rapidly quantify BoNT/E activity in avian blood with detection limits comparable to those of the mouse lethality assay. On the basis of the analysis of archived blood samples (n = 87) collected from bird carcasses during avian mortality investigations, BoTest Matrix E detected picomolar quantities of BoNT/E following a 2-h incubation and femtomolar quantities of BoNT/E following extended incubation (24 h) with 100% diagnostic specificity and 91% diagnostic sensitivity. PMID:21908624

Development of a Combined Human Transferrin-Hemoglobin Lateral Immunochromatographic Assay for Accurate and Rapid Fecal Occult Blood Test.

PubMed

Ye, Yuanyuan; Deng, Yin; Mao, Jinju; Yan, Qin; Huang, Yidan; Zhang, Jun; Zheng, Jian; Li, Yue; Chen, Weixian

2018-05-01

Fecal occult bloodtest (FOBT) plays an important role in the diagnosis of gastrointestinal diseases. The sensitivities of current FOBT methods are still not satisfactory. The aim of this study is to develop a combined human transferrin (HTf)-hemoglobin (HHb) lateral flow assay (LFA) for accurate and rapid FOBT. Monoclonal antibodies (MAbs) targeting HTf were developed by conventional methods and paired using LFA strips. The best HTf MAb pair was chosen according to the overall performance on testing limit and specificity. Meanwhile, HHb LFA strips were prepared using previously developed HHb MAbs. The testing limit and specificity were characterized. Based on the selected HTf MAb pair and the verified HHb MAb pair, combined HTf-HHb strips were developed. The combined HTf-HHb strips were used for FOBT of 400 human fecal samples, including 200 gastrointestinal bleeding specimens and 200 healthy subjects. For comparison, the homemade individual HTf and HHb strips, as well as three kinds of commercial FOBT strips, were also used for the FOBT. Two MAb pairs targeting HTf were developed for LFA. Two types of HTf strips were prepared accordingly. The type I was chosen due to its lower detection limit. Using the type I HTf MAb pair and the verified HHb- MAb pair, the combined HTf-HHb strips could detect the HTf at concentrations between 1 ng/mL and 1 x 106 ng/mL and the HHb between 10 ng/mL and 2.5 x 106 ng/mL. Compared to individual HTf and HHb strips and three kinds of commercial strips, the combined strips showed the highest diagnostic sensitivity in FOBT (96.0%). The specificity was a satisfactory 99%. Our combined HTf-HHb test strips are a very promising product for accurate and rapid FOBT.

αCGRP is essential for algesic exocytotic mobilization of TRPV1 channels in peptidergic nociceptors

PubMed Central

Devesa, Isabel; Ferrándiz-Huertas, Clotilde; Mathivanan, Sakthikumar; Wolf, Christoph; Luján, Rafael; Changeux, Jean-Pierre; Ferrer-Montiel, Antonio

2014-01-01

Proalgesic sensitization of peripheral nociceptors in painful syndromes is a complex molecular process poorly understood that involves mobilization of thermosensory receptors to the neuronal surface. However, whether recruitment of vesicular thermoTRP channels is a general mechanism underlying sensitization of all nociceptor types or is subtype-specific remains controversial. We report that sensitization-induced Ca2+-dependent exocytotic insertion of transient receptor potential vanilloid 1 (TRPV1) receptors to the neuronal plasma membrane is a mechanism specifically used by peptidergic nociceptors to potentiate their excitability. Notably, we found that TRPV1 is present in large dense-core vesicles (LDCVs) that were mobilized to the neuronal surface in response to a sensitizing insult. Deletion or silencing of calcitonin-gene–related peptide alpha (αCGRP) gene expression drastically reduced proalgesic TRPV1 potentiation in peptidergic nociceptors by abrogating its Ca2+-dependent exocytotic recruitment. These findings uncover a context-dependent molecular mechanism of TRPV1 algesic sensitization and a previously unrecognized role of αCGRP in LDCV mobilization in peptidergic nociceptors. Furthermore, these results imply that concurrent secretion of neuropeptides and channels in peptidergic C-type nociceptors facilitates a rapid modulation of pain signaling. PMID:25489075

Polymeric LabChip Real-Time PCR as a Point-of-Care-Potential Diagnostic Tool for Rapid Detection of Influenza A/H1N1 Virus in Human Clinical Specimens

PubMed Central

Song, Hyun-Ok; Kim, Je-Hyoung; Ryu, Ho-Sun; Lee, Dong-Hoon; Kim, Sun-Jin; Kim, Deog-Joong; Suh, In Bum; Choi, Du Young; In, Kwang-Ho; Kim, Sung-Woo; Park, Hyun

2012-01-01

It is clinically important to be able to detect influenza A/H1N1 virus using a fast, portable, and accurate system that has high specificity and sensitivity. To achieve this goal, it is necessary to develop a highly specific primer set that recognizes only influenza A viral genes and a rapid real-time PCR system that can detect even a single copy of the viral gene. In this study, we developed and validated a novel fluidic chip-type real-time PCR (LabChip real-time PCR) system that is sensitive and specific for the detection of influenza A/H1N1, including the pandemic influenza strain A/H1N1 of 2009. This LabChip real-time PCR system has several remarkable features: (1) It allows rapid quantitative analysis, requiring only 15 min to perform 30 cycles of real-time PCR. (2) It is portable, with a weight of only 5.5 kg. (3) The reaction cost is low, since it uses disposable plastic chips. (4) Its high efficiency is equivalent to that of commercially available tube-type real-time PCR systems. The developed disposable LabChip is an economic, heat-transferable, light-transparent, and easy-to-fabricate polymeric chip compared to conventional silicon- or glass-based labchip. In addition, our LabChip has large surface-to-volume ratios in micro channels that are required for overcoming time consumed for temperature control during real-time PCR. The efficiency of the LabChip real-time PCR system was confirmed using novel primer sets specifically targeted to the hemagglutinin (HA) gene of influenza A/H1N1 and clinical specimens. Eighty-five human clinical swab samples were tested using the LabChip real-time PCR. The results demonstrated 100% sensitivity and specificity, showing 72 positive and 13 negative cases. These results were identical to those from a tube-type real-time PCR system. This indicates that the novel LabChip real-time PCR may be an ultra-fast, quantitative, point-of-care-potential diagnostic tool for influenza A/H1N1 with a high sensitivity and specificity. PMID:23285281

Effects of short-term very low-calorie diet on intramyocellular lipid and insulin sensitivity in nondiabetic and type 2 diabetic subjects.

PubMed

Lara-Castro, Cristina; Newcomer, Bradley R; Rowell, Jennifer; Wallace, Penny; Shaughnessy, Sara M; Munoz, A Julian; Shiflett, Alanna M; Rigsby, Dana Y; Lawrence, Jeannine C; Bohning, Daryl E; Buchthal, Steven; Garvey, W Timothy

2008-01-01

The study aimed to analyze the effects of a short-term very low-calorie diet (VLCD) on intramyocellular lipid (IMCL), total body fat, and insulin sensitivity in a group of obese nondiabetic and type 2 diabetic subjects. Seven untreated type 2 diabetic and 5 obese nondiabetic individuals were studied before and after a 6-day VLCD using proton magnetic resonance spectroscopy to quantify IMCL, dual-energy x-ray absorptiometry to assess body fat, and hyperinsulinemic-euglycemic clamps to measure peripheral insulin sensitivity. In both groups, decrements in total body fat mass and body mass index were small but statistically significant. In contrast, the diet resulted in a pronounced reduction in IMCL compared with baseline values in nondiabetic subjects (56% decrease) and type 2 diabetic subjects (40% decrease) (P < .05), and this was accompanied by an overall 9.3% increase in maximally stimulated glucose disposal rate (P < .01). Intramyocellular lipid was significantly correlated with insulin sensitivity (r = -0.69, P < .01) and waist circumference (r = 0.72 and 0.83, baseline and postdiet, respectively; both P < .01), but neither IMCL nor insulin sensitivity was related to measures of general adiposity such as body mass index, percentage of body fat, or total body fat (P = not significant). In conclusion, short-term VLCD is accompanied by small decrements in general adiposity, marked decrease in IMCL, and an increase in insulin sensitivity in nondiabetic and type 2 diabetic subjects. Therefore, rapid amelioration of insulin resistance by VLCD can be partially explained by loss of IMCL both in nondiabetic and type 2 diabetic subjects in the absence of substantial changes in total body fat. These observations are consistent with the idea that insulin resistance is more directly related to IMCL rather than to body fat per se.

Neurobehavioral toxicity of cadmium sulfate to the planarian Dugesia dorotocephala

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

Grebe, E.; Schaeffer, D.J.

1991-05-01

The authors are developing bioassays which use planarians (free-living platyhelminthes) for the rapid determination of various types of toxicity, including acute mortality, tumorigenicity, and short-term neurobehavioral responses. Their motivation for using these animals is due to their importance as components of the aquatic ecology of unpolluted streams their sensitivity to low concentrations of environmental toxicants and the presence of a sensitive neurological system with a true brain which allows for complex social behavior. A previous paper described the results of a neurobehavioral bioassay using phenol in a crossover study. This paper reports a similar crossover study using cadmium sulfate.

Inactivation of human and simian rotaviruses by ozone

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

Vaughn, J.M.; Chen, Y.S.; Lindburg, K.

1987-09-01

The inactivation of simian rotavirus Sa-11 and human rotavirus type 2 (Wa) by ozone was compared at 4/sup 0/C by using single-particle virus stocks. Although the human strain was clearly more sensitive, both virus types were rapidly inactivated by ozone concentrations of 0.25 mg/liter or greater at all pH levels tested. Comparison of the virucidal activity of ozone with that of chlorine in identical experiments indicated little significant difference in rotavirus-inactivating efficiencies when the disinfectants were used at concentrations of 0.25 mg/liter or greater.

[Quantitative fluorogenic real-time PCR assay for respiratory syncytial virus detection].

PubMed

Zhang, Qi-wei; You, Shang-you; Sun, Ji-min; Wu, Qi; Yu, Chun-hua; Zhang, Chu-yu

2005-07-01

To Establish a rapid and objective quantitative fluorogenic real-time PCR assay for early detection of human respiratory syncytial virus (hRSV). Two pairs of primers and one TaqMan Fluorogenic probe that are specific for the recognition of the most conservative N gene of hRSV for virus detection with LighCycler PCR in 93 nasopharyngeal secretion specimens collected from infants and young children. The assay was compared with virus isolation, routine PCR, nested PCR, and enzyme-linked immunosorbent assay (ELISA). This TaqMan assay had a sensitivity of 1 x 10(2) cDNA copies/microl with a dynamic range between 1 x 10(2) and 1 x 10(7) cDNA copies/microl, which was the same as that of nested PCR, but 10 times more sensitive than routine PCR. The specificity of the assay was evaluated by comparing hRSV with polivirus type 1, coxsackie virus type 2, influenza A, influenza B and adenovirus type 7. A PCR product of the expected size (195 bp) was produced and fluorescence signal detected for hRSV, but not for any of the other viruses. The results in LightCycler and Rotor-Gene instrument were consistent. Forty-four specimens (43.9%) were hRSV-positive with this assay and 4 (4/93,4.3%) were hRSV-positive with ELISA, showing rather low correlation between the two methods. No visible relation was found between the concentration of hRSV RNA and severity of the disease. This assay is rapid, sensitive, specific and quantitative, and has the potential of wide application for early diagnosis of hRSV infection and evaluation of the therapeutic effect.

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.

Data security issues arising from integration of wireless access into healthcare networks.

PubMed

Frenzel, John C

2003-04-01

The versatility of having Ethernet speed connectivity without wires is rapidly driving adoption of wireless data networking by end users across all types of industry. Designed to be easy to configure and work among diverse platforms, wireless brings online data to mobile users. This functionality is particularly useful in modern clinical medicine. Wireless presents operators of networks containing or transmitting sensitive and confidential data with several new types of security vulnerabilities, and potentially opens previously protected core network resources to outside attack. Herein, we review the types of vulnerabilities, the tools necessary to exploit them, and strategies to thwart a successful attack.

A study on the sensitivity of self-powered neutron detectors (SPNDs)

NASA Astrophysics Data System (ADS)

Lee, Wanno; Cho, Gyuseong; Kim, Kwanghyun; Kim, Hee Joon; choi, Yuseon; Park, Moon Chu; Kim, Soongpyung

2001-08-01

Self-powered neutron detectors (SPNDs) are widely used in reactors to monitor neutron flux, while they have several advantages such as small size, and relatively simple electronics required in conjunction with those usages, they have some intrinsic problems of the low level of output current-a slow response time and the rapid change of sensitivity-that make it difficult to use for a long term. Monte Carlo simulation was used to calculate the escape probability as a function of the birth position of emitted beta particle for geometry of rhodium-based SPNDs. A simple numerical method calculated the initial generation rate of beta particles and the change of generation rate due to rhodium burnup. Using results of the simulation and the simple numerical method, the burnup profile of rhodium number density and the neutron sensitivity were calculated as a function of burnup time in reactors. This method was verified by the comparison of this and other papers, and data of YGN3.4 (Young Gwang Nuclear plant 3, 4) about the initial sensitivity. In addition, for improvement of some properties of rhodium-based SPNDs, which are currently used, a modified geometry is proposed. The proposed geometry, which is tube-type, is able to increase the initial sensitivity due to increase of the escape probability. The escape probability was calculated by changing the thickness of the insulator and compared solid-type with tube-type about each insulator thickness. The method used here can be applied to the analysis and design of other types of SPNDs.

Rapid detection of Shigella and enteroinvasive Escherichia coli in produce enrichments by a conventional multiplex PCR assay.

PubMed

Binet, Rachel; Deer, Deanne M; Uhlfelder, Samantha J

2014-06-01

Faster detection of contaminated foods can prevent adulterated foods from being consumed and minimize the risk of an outbreak of foodborne illness. A sensitive molecular detection method is especially important for Shigella because ingestion of as few as 10 of these bacterial pathogens can cause disease. The objectives of this study were to compare the ability of four DNA extraction methods to detect Shigella in six types of produce, post-enrichment, and to evaluate a new and rapid conventional multiplex assay that targets the Shigella ipaH, virB and mxiC virulence genes. This assay can detect less than two Shigella cells in pure culture, even when the pathogen is mixed with background microflora, and it can also differentiate natural Shigella strains from a control strain and eliminate false positive results due to accidental laboratory contamination. The four DNA extraction methods (boiling, PrepMan Ultra [Applied Biosystems], InstaGene Matrix [Bio-Rad], DNeasy Tissue kit [Qiagen]) detected 1.6 × 10(3)Shigella CFU/ml post-enrichment, requiring ∼18 doublings to one cell in 25 g of produce pre-enrichment. Lower sensitivity was obtained, depending on produce type and extraction method. The InstaGene Matrix was the most consistent and sensitive and the multiplex assay accurately detected Shigella in less than 90 min, outperforming, to the best of our knowledge, molecular assays currently in place for this pathogen. Published by Elsevier Ltd.

Aptamer Selection Express: A Novel Method for Rapid Single-Step Selection and Sensing of Aptamers

PubMed Central

Fan, Maomian; McBurnett, Shelly Roper; Andrews, Carrie J.; Allman, Amity M.; Bruno, John G.; Kiel, Johnathan L.

2008-01-01

Here we describe a new DNA capture element (DCE) sensing system, based on the quenching and dequenching of a double-stranded aptamer. This system shows very good sensitivity and thermal stability. While quenching, dequenching, and separating the DCE systems made from different aptamers (all selected by SELEX), an alternative method to rapidly select aptamers was developed—the Aptamer Selection Express (ASExp). This process has been used to select aptamers against different types of targets (Bacillus anthracis spores, Bacillus thuringiensis spores, MS-2 bacteriophage, ovalbumin, and botulinum neurotoxin). The DCE systems made from botulinum neurotoxin aptamers selected by ASExp have been investigated. The results of this investigation indicate that ASExp can be used to rapidly select aptamers for the DCE sensing system. PMID:19183794

Ketamine blocks bursting in the lateral habenula to rapidly relieve depression.

PubMed

Yang, Yan; Cui, Yihui; Sang, Kangning; Dong, Yiyan; Ni, Zheyi; Ma, Shuangshuang; Hu, Hailan

2018-02-14

The N-methyl-d-aspartate receptor (NMDAR) antagonist ketamine has attracted enormous interest in mental health research owing to its rapid antidepressant actions, but its mechanism of action has remained elusive. Here we show that blockade of NMDAR-dependent bursting activity in the 'anti-reward center', the lateral habenula (LHb), mediates the rapid antidepressant actions of ketamine in rat and mouse models of depression. LHb neurons show a significant increase in burst activity and theta-band synchronization in depressive-like animals, which is reversed by ketamine. Burst-evoking photostimulation of LHb drives behavioural despair and anhedonia. Pharmacology and modelling experiments reveal that LHb bursting requires both NMDARs and low-voltage-sensitive T-type calcium channels (T-VSCCs). Furthermore, local blockade of NMDAR or T-VSCCs in the LHb is sufficient to induce rapid antidepressant effects. Our results suggest a simple model whereby ketamine quickly elevates mood by blocking NMDAR-dependent bursting activity of LHb neurons to disinhibit downstream monoaminergic reward centres, and provide a framework for developing new rapid-acting antidepressants.

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.

Simultaneous multi-laser, multi-species trace-level sensing of gas mixtures by rapidly swept continuous-wave cavity-ringdown spectroscopy.

PubMed

He, Yabai; Kan, Ruifeng; Englich, Florian V; Liu, Wenqing; Orr, Brian J

2010-09-13

The greenhouse-gas molecules CO(2), CH(4), and H(2)O are detected in air within a few ms by a novel cavity-ringdown laser-absorption spectroscopy technique using a rapidly swept optical cavity and multi-wavelength coherent radiation from a set of pre-tuned near-infrared diode lasers. The performance of various types of tunable diode laser, on which this technique depends, is evaluated. Our instrument is both sensitive and compact, as needed for reliable environmental monitoring with high absolute accuracy to detect trace concentrations of greenhouse gases in outdoor air.

Rapid diagnostic tests for diagnosing uncomplicated non-falciparum or Plasmodium vivax malaria in endemic countries.

PubMed

Abba, Katharine; Kirkham, Amanda J; Olliaro, Piero L; Deeks, Jonathan J; Donegan, Sarah; Garner, Paul; Takwoingi, Yemisi

2014-12-18

In settings where both Plasmodium vivax and Plasmodium falciparum infection cause malaria, rapid diagnostic tests (RDTs) need to distinguish which species is causing the patients' symptoms, as different treatments are required. Older RDTs incorporated two test lines to distinguish malaria due to P. falciparum, from malaria due to any other Plasmodium species (non-falciparum). These RDTs can be classified according to which antibodies they use: Type 2 RDTs use HRP-2 (for P. falciparum) and aldolase (all species); Type 3 RDTs use HRP-2 (for P. falciparum) and pLDH (all species); Type 4 use pLDH (fromP. falciparum) and pLDH (all species).More recently, RDTs have been developed to distinguish P. vivax parasitaemia by utilizing a pLDH antibody specific to P. vivax. To assess the diagnostic accuracy of RDTs for detecting non-falciparum or P. vivax parasitaemia in people living in malaria-endemic areas who present to ambulatory healthcare facilities with symptoms suggestive of malaria, and to identify which types and brands of commercial test best detect non-falciparum and P. vivax malaria. We undertook a comprehensive search of the following databases up to 31 December 2013: Cochrane Infectious Diseases Group Specialized Register; MEDLINE; EMBASE; MEDION; Science Citation Index; Web of Knowledge; African Index Medicus; LILACS; and IndMED. Studies comparing RDTs with a reference standard (microscopy or polymerase chain reaction) in blood samples from a random or consecutive series of patients attending ambulatory health facilities with symptoms suggestive of malaria in non-falciparum endemic areas. For each study, two review authors independently extracted a standard set of data using a tailored data extraction form. We grouped comparisons by type of RDT (defined by the combinations of antibodies used), and combined in meta-analysis where appropriate. Average sensitivities and specificities are presented alongside 95% confidence intervals (95% CI). We included 47 studies enrolling 22,862 participants. Patient characteristics, sampling methods and reference standard methods were poorly reported in most studies. RDTs detecting 'non-falciparum' parasitaemiaEleven studies evaluated Type 2 tests compared with microscopy, 25 evaluated Type 3 tests, and 11 evaluated Type 4 tests. In meta-analyses, average sensitivities and specificities were 78% (95% CI 73% to 82%) and 99% (95% CI 97% to 99%) for Type 2 tests, 78% (95% CI 69% to 84%) and 99% (95% CI 98% to 99%) for Type 3 tests, and 89% (95% CI 79% to 95%) and 98% (95% CI 97% to 99%) for Type 4 tests, respectively. Type 4 tests were more sensitive than both Type 2 (P = 0.01) and Type 3 tests (P = 0.03).Five studies compared Type 3 tests with PCR; in meta-analysis, the average sensitivity and specificity were 81% (95% CI 72% to 88%) and 99% (95% CI 97% to 99%) respectively. RDTs detecting P.vivax parasitaemiaEight studies compared pLDH tests to microscopy; the average sensitivity and specificity were 95% (95% CI 86% to 99%) and 99% (95% CI 99% to 100%), respectively. RDTs designed to detect P. vivax specifically, whether alone or as part of a mixed infection, appear to be more accurate than older tests designed to distinguish P. falciparum malaria from non-falciparum malaria. Compared to microscopy, these tests fail to detect around 5% ofP. vivax cases. This Cochrane Review, in combination with other published information about in vitro test performance and stability in the field, can assist policy-makers to choose between the available RDTs.

A genetic variant of the sperm-specific SLO3 K+ channel has altered pH and Ca2+ sensitivities.

PubMed

Geng, Yanyan; Ferreira, Juan J; Dzikunu, Victor; Butler, Alice; Lybaert, Pascale; Yuan, Peng; Magleby, Karl L; Salkoff, Lawrence; Santi, Celia M

2017-05-26

To fertilize an oocyte, sperm must first undergo capacitation in which the sperm plasma membrane becomes hyperpolarized via activation of potassium (K + ) channels and resultant K + efflux. Sperm-specific SLO3 K + channels are responsible for these membrane potential changes critical for fertilization in mouse sperm, and they are only sensitive to pH i However, in human sperm, the major K + conductance is both Ca 2+ - and pH i -sensitive. It has been debated whether Ca 2+ -sensitive SLO1 channels substitute for human SLO3 (hSLO3) in human sperm or whether human SLO3 channels have acquired Ca 2+ sensitivity. Here we show that hSLO3 is rapidly evolving and reveal a natural structural variant with enhanced apparent Ca 2+ and pH sensitivities. This variant allele (C382R) alters an amino acid side chain at a principal interface between the intramembrane-gated pore and the cytoplasmic gating ring of the channel. Because the gating ring contains sensors to intracellular factors such as pH and Ca 2+ , the effectiveness of transduction between the gating ring and the pore domain appears to be enhanced. Our results suggest that sperm-specific genes can evolve rapidly and that natural genetic variation may have led to a SLO3 variant that differs from wild type in both pH and intracellular Ca 2+ sensitivities. Whether this physiological variation confers differences in fertility among males remains to be established. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

A procedure for estimating Bacillus cereus spores in soil and stream-sediment samples - A potential exploration technique

USGS Publications Warehouse

Watterson, J.R.

1985-01-01

The presence of bacterial spores of the Bacillus cereus group in soils and stream sediments appears to be a sensitive indicator of several types of concealed mineral deposits, including vein-type gold deposits. The B. cereus assay is rapid, inexpensive, and inherently reproducible. The test, currently under investigation for its potential in mineral exploration, is recommended for use on a research basis. Among the aerobic spore-forming bacilli, only B. cereus and closely related strains produce an opaque zone in egg-yolk emulsion agar. This characteristic, also known as the Nagler of lecitho-vitellin reaction, has long been used to rapidly indentify and estimate presumptive B. cereus. The test is here adapted to permit rapid estimation of B. cereus spores in soil and stream-sediment samples. Relative standard deviation was 10.3% on counts obtained from two 40-replicate pour-plate determinations. As many as 40 samples per day can be processed. Enough procedural detail is included to permit investigation of the test in conventional geochemical laboratories using standard microbiological safety precautions. ?? 1985.

Thyroid hormone determines the start of the sensitive period of imprinting and primes later learning.

PubMed

Yamaguchi, Shinji; Aoki, Naoya; Kitajima, Takaaki; Iikubo, Eiji; Katagiri, Sachiko; Matsushima, Toshiya; Homma, Koichi J

2012-01-01

Filial imprinting in precocial birds is the process of forming a social attachment during a sensitive or critical period, restricted to the first few days after hatching. Imprinting is considered to be part of early learning to aid the survival of juveniles by securing maternal care. Here we show that the thyroid hormone 3,5,3'-triiodothyronine (T(3)) determines the start of the sensitive period. Imprinting training in chicks causes rapid inflow of T(3), converted from circulating plasma thyroxine by Dio2, type 2 iodothyronine deiodinase, in brain vascular endothelial cells. The T(3) thus initiates and extends the sensitive period to last more than 1 week via non-genomic mechanisms and primes subsequent learning. Even in non-imprinted chicks whose sensitive period has ended, exogenous T(3) enables imprinting. Our findings indicate that T(3) determines the start of the sensitive period for imprinting and has a critical role in later learning.

Thyroid hormone determines the start of the sensitive period of imprinting and primes later learning

PubMed Central

Yamaguchi, Shinji; Aoki, Naoya; Kitajima, Takaaki; Iikubo, Eiji; Katagiri, Sachiko; Matsushima, Toshiya; Homma, Koichi J.

2012-01-01

Filial imprinting in precocial birds is the process of forming a social attachment during a sensitive or critical period, restricted to the first few days after hatching. Imprinting is considered to be part of early learning to aid the survival of juveniles by securing maternal care. Here we show that the thyroid hormone 3,5,3′-triiodothyronine (T3) determines the start of the sensitive period. Imprinting training in chicks causes rapid inflow of T3, converted from circulating plasma thyroxine by Dio2, type 2 iodothyronine deiodinase, in brain vascular endothelial cells. The T3 thus initiates and extends the sensitive period to last more than 1 week via non-genomic mechanisms and primes subsequent learning. Even in non-imprinted chicks whose sensitive period has ended, exogenous T3 enables imprinting. Our findings indicate that T3 determines the start of the sensitive period for imprinting and has a critical role in later learning. PMID:23011135

Applying geologic sensitivity analysis to environmental risk management: The financial implications

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

Rogers, D.T.

The financial risks associated with environmental contamination can be staggering and are often difficult to identify and accurately assess. Geologic sensitivity analysis is gaining recognition as a significant and useful tool that can empower the user with crucial information concerning environmental risk management and brownfield redevelopment. It is particularly useful when (1) evaluating the potential risks associated with redevelopment of historical industrial facilities (brownfields) and (2) planning for future development, especially in areas of rapid development because the number of potential contaminating sources often increases with an increase in economic development. An examination of the financial implications relating to geologicmore » sensitivity analysis in southeastern Michigan from numerous case studies indicate that the environmental cost of contamination may be 100 to 1,000 times greater at a geologically sensitive location compared to the least sensitive location. Geologic sensitivity analysis has demonstrated that near-surface geology may influence the environmental impact of a contaminated site to a greater extent than the amount and type of industrial development.« less

A comprehensive NMR methodology to assess the composition of biobased and biodegradable polymers in contact with food.

PubMed

Gratia, Audrey; Merlet, Denis; Ducruet, Violette; Lyathaud, Cédric

2015-01-01

A nuclear magnetic resonance (NMR) methodology was assessed regarding the identification and quantification of additives in three types of polylactide (PLA) intended as food contact materials. Additives were identified using the LNE/NMR database which clusters NMR datasets on more than 130 substances authorized by European Regulation No. 10/2011. Of the 12 additives spiked in the three types of PLA pellets, 10 were rapidly identified by the database and correlated with spectral comparison. The levels of the 12 additives were estimated using quantitative NMR combined with graphical computation. A comparison with chromatographic methods tended to prove the sensitivity of NMR by demonstrating an analytical difference of less than 15%. Our results therefore demonstrated the efficiency of the proposed NMR methodology for rapid assessment of the composition of PLA. Copyright © 2014 Elsevier B.V. All rights reserved.

Sensitivity and Specificity of Human Immunodeficiency Virus Rapid Serologic Assays and Testing Algorithms in an Antenatal Clinic in Abidjan, Ivory Coast

PubMed Central

Koblavi-Dème, Stéphania; Maurice, Chantal; Yavo, Daniel; Sibailly, Toussaint S.; N′guessan, Kabran; Kamelan-Tano, Yvonne; Wiktor, Stefan Z.; Roels, Thierry H.; Chorba, Terence; Nkengasong, John N.

2001-01-01

To evaluate serologic testing algorithms for human immunodeficiency virus (HIV) based on a combination of rapid assays among persons with HIV-1 (non-B subtypes) infection, HIV-2 infection, and HIV-1–HIV-2 dual infections in Abidjan, Ivory Coast, a total of 1,216 sera with known HIV serologic status were used to evaluate the sensitivity and specificity of four rapid assays: Determine HIV-1/2, Capillus HIV-1/HIV-2, HIV-SPOT, and Genie II HIV-1/HIV-2. Two serum panels obtained from patients recently infected with HIV-1 subtypes B and non-B were also included. Based on sensitivity and specificity, three of the four rapid assays were evaluated prospectively in parallel (serum samples tested by two simultaneous rapid assays) and serial (serum samples tested by two consecutive rapid assays) testing algorithms. All assays were 100% sensitive, and specificities ranged from 99.4 to 100%. In the prospective evaluation, both the parallel and serial algorithms were 100% sensitive and specific. Our results suggest that rapid assays have high sensitivity and specificity and, when used in parallel or serial testing algorithms, yield results similar to those of enzyme-linked immunosorbent assay-based testing strategies. HIV serodiagnosis based on rapid assays may be a valuable alternative in implementing HIV prevention and surveillance programs in areas where sophisticated laboratories are difficult to establish. PMID:11325995

Rapid Damage Assessment. Volume I. Methodology for Selecting Repair Area of Ordnance-Damaged Pavements.

DTIC Science & Technology

1980-09-01

this system be given no further consideration. 14AGNETOMETER TECHNIQUES Four types of magnetometers are commonly in use today: fluxgate , proton...that are cumbersome to operate and less accurate than fluxgate and proton mag- netometers. The proton magnetometer is also gradually replacing the... fluxgate magnetometer because of its greater sensitivity (I gamma or better), absolute accuracy, nonmoving parts, and its ability Lo measure absolute

Multiplex real-time RT-PCR assay for bovine viral diarrhea virus type 1, type 2 and HoBi-like pestivirus.

PubMed

Mari, Viviana; Losurdo, Michele; Lucente, Maria Stella; Lorusso, Eleonora; Elia, Gabriella; Martella, Vito; Patruno, Giovanni; Buonavoglia, Domenico; Decaro, Nicola

2016-03-01

HoBi-like pestiviruses are emerging pestiviruses that infect cattle causing clinical forms overlapping to those induced by bovine viral diarrhea virus (BVDV) 1 and 2. As a consequence of their widespread distribution reported in recent years, molecular tools for rapid discrimination among pestiviruses infecting cattle are needed. The aim of the present study was to develop a multiplex real-time RT-PCR assay, based on the TaqMan technology, for the rapid and unambiguous characterisation of all bovine pestiviruses, including the emerging HoBi-like strains. The assay was found to be sensitive, specific and repeatable, ensuring detection of as few as 10(0)-10(1) viral RNA copies. No cross-reactions between different pestiviral species were observed even in samples artificially contaminated with more than one pestivirus. Analysis of field samples tested positive for BVDV-1, BVDV-2 or HoBi-like virus by a nested PCR protocol revealed that the developed TaqMan assay had equal or higher sensitivity and was able to discriminate correctly the viral species in all tested samples, whereas a real-time RT-PCR assay previously developed for HoBi-like pestivirus detection showed cross-reactivity with few high-titre BVDV-2 samples. Copyright © 2015 Elsevier B.V. All rights reserved.

Investigation of low-loss spectra and near-edge fine structure of polymers by PEELS

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

Heckmann, W.

Transmission electron microscopy has changed from a purely imaging method to an analytical method. This has been facilitated particularly by equipping electron microscopes with energy filters and with parallel electron energy loss spectrometers (PEELS). Because of their relatively high energy resolution (1 to 2 eV) they provide information not only on the elements present but also on the type of bonds between the molecular groups. Polymers are radiation sensitive and the molecular bonds change as the spectrum is being recorded. This can be observed with PEEL spectrometers that are able to record spectra with high sensitivity and in rapid succession.

Thermo-elastic optical coherence tomography.

PubMed

Wang, Tianshi; Pfeiffer, Tom; Wu, Min; Wieser, Wolfgang; Amenta, Gaetano; Draxinger, Wolfgang; van der Steen, Antonius F W; Huber, Robert; Soest, Gijs van

2017-09-01

The absorption of nanosecond laser pulses induces rapid thermo-elastic deformation in tissue. A sub-micrometer scale displacement occurs within a few microseconds after the pulse arrival. In this Letter, we investigate the laser-induced thermo-elastic deformation using a 1.5 MHz phase-sensitive optical coherence tomography (OCT) system. A displacement image can be reconstructed, which enables a new modality of phase-sensitive OCT, called thermo-elastic OCT. An analysis of the results shows that the optical absorption is a dominating factor for the displacement. Thermo-elastic OCT is capable of visualizing inclusions that do not appear on the structural OCT image, providing additional tissue type information.

Variation in ultraviolet radiation and diabetes: evidence of an epigenetic effect that modulates diabetics’ lifespan

PubMed Central

2013-01-01

Background Published research has shown that month-of-birth variations modulate the incidence of adult human diseases. This article explores diabetes type 2 as one of those diseases. This study uses the death records of approximately 829,000 diabetics (approximately 90% were type-2) born before the year 1945 (and dying between 1979 and 2005) to show that variations in adult lifespan vary with ultraviolet radiation (UVR) at solar cycle peaks (MAX, approximately a three-year period) with less at non-peaks (MIN, approximately an eight-year period). The MAX minus MIN (in years) was our measure of sensitivity (for example, responsiveness) to long-term variations in UVR. Results Diabetics were less sensitive than non-diabetics, and ethnic minorities were more sensitive than whites. Diabetic males gained 6.1 years, and females 2.3 years over non-diabetics, with diabetic males gaining an average of 3.8 years over diabetic females. Most variation in lifespan occurred in those conceived around the seasonal equinoxes, suggesting that the human epigenome at conception is especially influenced by rapid variation in UVR. With rapidly decreasing UVR at conception, lifespan decreased in the better-nourished, white, female diabetic population. Conclusions Rapidly changing UVR at the equinoxes modulates the expression of an epigenome involving the conservation of energy, a mechanism especially canalized in women. Decreasing UVR at conception and early gestation stimulates energy conservation in persons we consider ‘diabetic’ in today’s environment of caloric surfeit. In the late 19th and early 20th centuries ethnic minorities had poorer nutrition, laborious work, and leaner bodies, and in that environment a calorie-conserving epigenome was a survival advantage. Ethnic minorities with a similar epigenome lived long enough to express diabetes as we define it today and exceeded the lifespan of their non-diabetic contemporaries, while that epigenome in diabetics in the nutritional environment of today is detrimental to lifespan. PMID:23548082

Rapid screening for the detection of HLA-B57 and HLA-B58 in prevention of drug hypersensitivity.

PubMed

Kostenko, L; Kjer-Nielsen, L; Nicholson, I; Hudson, F; Lucas, A; Foley, B; Chen, K; Lynch, K; Nguyen, J; Wu, A H B; Tait, B D; Holdsworth, R; Mallal, S; Rossjohn, J; Bharadwaj, M; McCluskey, J

2011-07-01

HLA-B57 and HLA-B58 are major histocompatibility class (MHC)-I allotypes that are potentially predictive of important clinical immune phenotypes. HLA-B*5701 is strongly associated with hypersensitivity to the HIV drug abacavir, liver toxicity from the antibiotic flucloxacillin and is a marker for slow progression of HIV AIDS. HLA-B*5801 is associated with hypersensitivity to allopurinol used to treat hyperuricaemia and recurrent gout. Here we describe a monoclonal antibody (mAb) specific for HLA-B57 and HLA-B58 that provides an inexpensive and sensitive screen for these MHC-I allotypes. The usefulness of HLA-B57 screening for prediction of abacavir hypersensitivity was shown in three independent laboratories, including confirmation of the mAb sensitivity and specificity in a cohort of patients enrolled in the PREDICT-1 trial. Our data show that patients who test negative by mAb screening comprise 90%-95% of all individuals in most human populations and require no further human leukocyte antigen (HLA) typing. Patients who test positive by mAb screening should proceed to high-resolution typing to ascertain the presence of HLA-B*5701 or HLA-B*5801. Hence, mAb screening provides a low-cost alternative to high-resolution typing of all patients and lends itself to point-of-care diagnostics and rapid ascertainment of low-risk patients who can begin immediate therapy with abacavir, flucloxacillin or allopurinol. © 2011 John Wiley & Sons A/S.

Sensitivity study and parameter optimization of OCD tool for 14nm finFET process

NASA Astrophysics Data System (ADS)

Zhang, Zhensheng; Chen, Huiping; Cheng, Shiqiu; Zhan, Yunkun; Huang, Kun; Shi, Yaoming; Xu, Yiping

2016-03-01

Optical critical dimension (OCD) measurement has been widely demonstrated as an essential metrology method for monitoring advanced IC process in the technology node of 90 nm and beyond. However, the rapidly shrunk critical dimensions of the semiconductor devices and the increasing complexity of the manufacturing process bring more challenges to OCD. The measurement precision of OCD technology highly relies on the optical hardware configuration, spectral types, and inherently interactions between the incidence of light and various materials with various topological structures, therefore sensitivity analysis and parameter optimization are very critical in the OCD applications. This paper presents a method for seeking the optimum sensitive measurement configuration to enhance the metrology precision and reduce the noise impact to the greatest extent. In this work, the sensitivity of different types of spectra with a series of hardware configurations of incidence angles and azimuth angles were investigated. The optimum hardware measurement configuration and spectrum parameter can be identified. The FinFET structures in the technology node of 14 nm were constructed to validate the algorithm. This method provides guidance to estimate the measurement precision before measuring actual device features and will be beneficial for OCD hardware configuration.

RNAi screen for rapid therapeutic target identification in leukemia patients

PubMed Central

Tyner, Jeffrey W.; Deininger, Michael W.; Loriaux, Marc M.; Chang, Bill H.; Gotlib, Jason R.; Willis, Stephanie G.; Erickson, Heidi; Kovacsovics, Tibor; O'Hare, Thomas; Heinrich, Michael C.; Druker, Brian J.

2009-01-01

Targeted therapy has vastly improved outcomes in certain types of cancer. Extension of this paradigm across a broad spectrum of malignancies will require an efficient method to determine the molecular vulnerabilities of cancerous cells. Improvements in sequencing technology will soon enable high-throughput sequencing of entire genomes of cancer patients; however, determining the relevance of identified sequence variants will require complementary functional analyses. Here, we report an RNAi-assisted protein target identification (RAPID) technology that individually assesses targeting of each member of the tyrosine kinase gene family. We demonstrate that RAPID screening of primary leukemia cells from 30 patients identifies targets that are critical to survival of the malignant cells from 10 of these individuals. We identify known, activating mutations in JAK2 and K-RAS, as well as patient-specific sensitivity to down-regulation of FLT1, CSF1R, PDGFR, ROR1, EPHA4/5, JAK1/3, LMTK3, LYN, FYN, PTK2B, and N-RAS. We also describe a previously undescribed, somatic, activating mutation in the thrombopoietin receptor that is sensitive to down-stream pharmacologic inhibition. Hence, the RAPID technique can quickly identify molecular vulnerabilities in malignant cells. Combination of this technique with whole-genome sequencing will represent an ideal tool for oncogenic target identification such that specific therapies can be matched with individual patients. PMID:19433805

Rapid Airplane Parametric Input Design (RAPID)

NASA Technical Reports Server (NTRS)

Smith, Robert E.

1995-01-01

RAPID is a methodology and software system to define a class of airplane configurations and directly evaluate surface grids, volume grids, and grid sensitivity on and about the configurations. A distinguishing characteristic which separates RAPID from other airplane surface modellers is that the output grids and grid sensitivity are directly applicable in CFD analysis. A small set of design parameters and grid control parameters govern the process which is incorporated into interactive software for 'real time' visual analysis and into batch software for the application of optimization technology. The computed surface grids and volume grids are suitable for a wide range of Computational Fluid Dynamics (CFD) simulation. The general airplane configuration has wing, fuselage, horizontal tail, and vertical tail components. The double-delta wing and tail components are manifested by solving a fourth order partial differential equation (PDE) subject to Dirichlet and Neumann boundary conditions. The design parameters are incorporated into the boundary conditions and therefore govern the shapes of the surfaces. The PDE solution yields a smooth transition between boundaries. Surface grids suitable for CFD calculation are created by establishing an H-type topology about the configuration and incorporating grid spacing functions in the PDE equation for the lifting components and the fuselage definition equations. User specified grid parameters govern the location and degree of grid concentration. A two-block volume grid about a configuration is calculated using the Control Point Form (CPF) technique. The interactive software, which runs on Silicon Graphics IRIS workstations, allows design parameters to be continuously varied and the resulting surface grid to be observed in real time. The batch software computes both the surface and volume grids and also computes the sensitivity of the output grid with respect to the input design parameters by applying the precompiler tool ADIFOR to the grid generation program. The output of ADIFOR is a new source code containing the old code plus expressions for derivatives of specified dependent variables (grid coordinates) with respect to specified independent variables (design parameters). The RAPID methodology and software provide a means of rapidly defining numerical prototypes, grids, and grid sensitivity of a class of airplane configurations. This technology and software is highly useful for CFD research for preliminary design and optimization processes.

Rapid detection of highly pathogenic porcine reproductive and respiratory syndrome virus by a fluorescent probe-based isothermal recombinase polymerase amplification assay.

PubMed

Yang, Yang; Qin, Xiaodong; Sun, Yingjun; Chen, Ting; Zhang, Zhidong

2016-12-01

A novel fluorescent probe-based real-time reverse transcription recombinase polymerase amplification (real-time RT-RPA) assay was developed for rapid detection of highly pathogenic type 2 porcine reproductive and respiratory syndrome virus (HP-PRRSV). The sensitivity analysis showed that the detection limit of RPA was 70 copies of HP-PRRSV RNA/reaction. The real-time RT-RPA highly specific amplified HP-PRRSV with no cross-reaction with classic PRRSV, classic swine fever virus, pseudorabies virus, and foot-and-mouth disease virus. Assessment with 125 clinical samples showed that the developed real-time RT-RPA assay was well correlated with real-time RT-qPCR assays for detection of HP-PRRSV. These results suggest that the developed real-time RT-RPA assay is suitable for rapid detection of HP-PRRSV.

The Broad Spectrum Receptor Tyrosine Kinase Inhibitor Dovitinib Suppresses Growth of BRAF Mutant Melanoma Cells in Combination with Other Signaling Pathway Inhibitors

PubMed Central

Langdon, Casey G.; Held, Matthew A.; Platt, James T.; Meeth, Katrina; Iyidogan, Pinar; Mamillapalli, Ramanaiah; Koo, Andrew B.; Klein, Michael; Liu, Zongzhi; Bosenberg, Marcus W.; Stern, David F.

2016-01-01

Summary BRAF inhibitors have revolutionized treatment of mutant BRAF metastatic melanomas. However, resistance develops rapidly following BRAF inhibitor treatment. We have found that BRAF-mutant melanoma cell lines are more sensitive than wild-type BRAF cells to the small molecule tyrosine kinase inhibitor dovitinib. Sensitivity is associated with inhibition of a series of known dovitinib targets. Dovitinib in combination with several agents inhibits growth more effectively than either agent alone. These combinations inhibit BRAF-mutant melanoma and colorectal carcinoma cell lines, including cell lines with intrinsic or selected BRAF inhibitor resistance. Hence, combinations of dovitinib with second agents are potentially effective therapies for BRAF-mutant melanomas, regardless of their sensitivity to BRAF inhibitors. PMID:25854919

[Voltage-gated potassium channels and human neurological diseases].

PubMed

Jin, Hong-Wei; Wang, Xiao-Liang

2002-01-01

Voltage-gated potassium channels (Kv) is the largest, most complex in potassium channel superfamily. It can be divided into Kv alpha subunit and auxiliary two groups. The roles of some Kv channels types, e.g. rapidly inactivating (A-Type channel) and muscarine sensitive channels (M-type channel) are beginning to be understood. They are prominent in nervous system, acting in delicate and accurate ways to control or modify many physiological and pathological functions including membrane excitability, neurotransmitter release, cell proliferation or degeneration, signal transduction in neuronal network. Many human neurological disease pathogenesis are found to be related to mutant of Kv-channels subunit or subtype, such as, learning and memory impairing, ataxia, epilepsy, deafness, etc.

Rapidity and species dependence of particle production at large transverse momentum for d+Au collisions at sNN=200 GeV

NASA Astrophysics Data System (ADS)

Abelev, B. I.; Adams, J.; Aggarwal, M. M.; Ahammed, Z.; Amonett, J.; Anderson, B. D.; Anderson, M.; Arkhipkin, D.; Averichev, G. S.; Bai, Y.; Balewski, J.; Barannikova, O.; Barnby, L. S.; Baudot, J.; Bekele, S.; Belaga, V. V.; Bellingeri-Laurikainen, A.; Bellwied, R.; Benedosso, F.; Bhardwaj, S.; Bhasin, A.; Bhati, A. K.; Bichsel, H.; Bielcik, J.; Bielcikova, J.; Bland, L. C.; Blyth, S.-L.; Bonner, B. E.; Botje, M.; Bouchet, J.; Brandin, A. V.; Bravar, A.; Bystersky, M.; Cadman, R. V.; Cai, X. Z.; Caines, H.; Sánchez, M. Calderón De La Barca; Castillo, J.; Catu, O.; Cebra, D.; Chajecki, Z.; Chaloupka, P.; Chattopadhyay, S.; Chen, H. F.; Chen, J. H.; Cheng, J.; Cherney, M.; Chikanian, A.; Christie, W.; Coffin, J. P.; Cormier, T. M.; Cosentino, M. R.; Cramer, J. G.; Crawford, H. J.; Das, D.; Das, S.; Daugherity, M.; Moura, M. M. De; Dedovich, T. G.; Dephillips, M.; Derevschikov, A. A.; Didenko, L.; Dietel, T.; Djawotho, P.; Dogra, S. M.; Dong, W. J.; Dong, X.; Draper, J. E.; Du, F.; Dunin, V. B.; Dunlop, J. C.; Mazumdar, M. R. Dutta; Eckardt, V.; Edwards, W. R.; Efimov, L. G.; Emelianov, V.; Engelage, J.; Eppley, G.; Erazmus, B.; Estienne, M.; Fachini, P.; Fatemi, R.; Fedorisin, J.; Filimonov, K.; Filip, P.; Finch, E.; Fine, V.; Fisyak, Y.; Fu, J.; Gagliardi, C. A.; Gaillard, L.; Ganti, M. S.; Ghazikhanian, V.; Ghosh, P.; Gonzalez, J. E.; Gorbunov, Y. G.; Gos, H.; Grebenyuk, O.; Grosnick, D.; Guertin, S. M.; Guimaraes, K. S. F. F.; Guo, Y.; Gupta, N.; Gutierrez, T. D.; Haag, B.; Hallman, T. J.; Hamed, A.; Harris, J. W.; He, W.; Heinz, M.; Henry, T. W.; Hepplemann, S.; Hippolyte, B.; Hirsch, A.; Hjort, E.; Hoffman, A. M.; Hoffmann, G. W.; Horner, M. J.; Huang, H. Z.; Huang, S. L.; Hughes, E. W.; Humanic, T. J.; Igo, G.; Jacobs, P.; Jacobs, W. W.; Jakl, P.; Jia, F.; Jiang, H.; Jones, P. G.; Judd, E. G.; Kabana, S.; Kang, K.; Kapitan, J.; Kaplan, M.; Keane, D.; Kechechyan, A.; Khodyrev, V. Yu.; Kim, B. C.; Kiryluk, J.; Kisiel, A.; Kislov, E. M.; Klein, S. R.; Kocoloski, A.; Koetke, D. D.; Kollegger, T.; Kopytine, M.; Kotchenda, L.; Kouchpil, V.; Kowalik, K. L.; Kramer, M.; Kravtsov, P.; Kravtsov, V. I.; Krueger, K.; Kuhn, C.; Kulikov, A. I.; Kumar, A.; Kuznetsov, A. A.; Lamont, M. A. C.; Landgraf, J. M.; Lange, S.; Lapointe, S.; Laue, F.; Lauret, J.; Lebedev, A.; Lednicky, R.; Lee, C.-H.; Lehocka, S.; Levine, M. J.; Li, C.; Li, Q.; Li, Y.; Lin, G.; Lin, X.; Lindenbaum, S. J.; Lisa, M. A.; Liu, F.; Liu, H.; Liu, J.; Liu, L.; Liu, Z.; Ljubicic, T.; Llope, W. J.; Long, H.; Longacre, R. S.; Lopez-Noriega, M.; Love, W. A.; Lu, Y.; Ludlam, T.; Lynn, D.; Ma, G. L.; Ma, J. G.; Ma, Y. G.; Magestro, D.; Mahapatra, D. P.; Majka, R.; Mangotra, L. K.; Manweiler, R.; Margetis, S.; Markert, C.; Martin, L.; Matis, H. S.; Matulenko, Yu. A.; McClain, C. J.; McShane, T. S.; Melnick, Yu.; Meschanin, A.; Millane, J.; Miller, M. L.; Minaev, N. G.; Mioduszewski, S.; Mironov, C.; Mischke, A.; Mishra, D. K.; Mitchell, J.; Mohanty, B.; Molnar, L.; Moore, C. F.; Morozov, D. A.; Munhoz, M. G.; Nandi, B. K.; Nattrass, C.; Nayak, T. K.; Nelson, J. M.; Netrakanti, P. K.; Nikitin, V. A.; Nogach, L. V.; Nurushev, S. B.; Odyniec, G.; Ogawa, A.; Okorokov, V.; Oldenburg, M.; Olson, D.; Pachr, M.; Pal, S. K.; Panebratsev, Y.; Panitkin, S. Y.; Pavlinov, A. I.; Pawlak, T.; Peitzmann, T.; Perevoztchikov, V.; Perkins, C.; Peryt, W.; Petrov, V. A.; Phatak, S. C.; Picha, R.; Planinic, M.; Pluta, J.; Poljak, N.; Porile, N.; Porter, J.; Poskanzer, A. M.; Potekhin, M.; Potrebenikova, E.; Potukuchi, B. V. K. S.; Prindle, D.; Pruneau, C.; Putschke, J.; Rakness, G.; Raniwala, R.; Raniwala, S.; Ray, R. L.; Razin, S. V.; Reinnarth, J.; Relyea, D.; Retiere, F.; Ridiger, A.; Ritter, H. G.; Roberts, J. B.; Rogachevskiy, O. V.; Romero, J. L.; Rose, A.; Roy, C.; Ruan, L.; Russcher, M. J.; Sahoo, R.; Sakuma, T.; Salur, S.; Sandweiss, J.; Sarsour, M.; Sazhin, P. S.; Schambach, J.; Scharenberg, R. P.; Schmitz, N.; Schweda, K.; Seger, J.; Selyuzhenkov, I.; Seyboth, P.; Shabetai, A.; Shahaliev, E.; Shao, M.; Sharma, M.; Shen, W. Q.; Shimanskiy, S. S.; Sichtermann, E.; Simon, F.; Singaraju, R. N.; Smirnov, N.; Snellings, R.; Sood, G.; Sorensen, P.; Sowinski, J.; Speltz, J.; Spinka, H. M.; Srivastava, B.; Stadnik, A.; Stanislaus, T. D. S.; Stock, R.; Stolpovsky, A.; Strikhanov, M.; Stringfellow, B.; Suaide, A. A. P.; Sugarbaker, E.; Sumbera, M.; Sun, Z.; Surrow, B.; Swanger, M.; Symons, T. J. M.; Toledo, A. Szanto De; Tai, A.; Takahashi, J.; Tang, A. H.; Tarnowsky, T.; Thein, D.; Thomas, J. H.; Timmins, A. R.; Timoshenko, S.; Tokarev, M.; Trainor, T. A.; Trentalange, S.; Tribble, R. E.; Tsai, O. D.; Ulery, J.; Ullrich, T.; Underwood, D. G.; Buren, G. Van; Kolk, N. Van Der; Leeuwen, M. Van; Molen, A. M. Vander; Varma, R.; Vasilevski, I. M.; Vasiliev, A. N.; Vernet, R.; Vigdor, S. E.; Viyogi, Y. P.; Vokal, S.; Voloshin, S. A.; Waggoner, W. T.; Wang, F.; Wang, G.; Wang, J. S.; Wang, X. L.; Wang, Y.; Watson, J. W.; Webb, J. C.; Westfall, G. D.; Wetzler, A.; , C. Whitten, Jr.; Wieman, H.; Wissink, S. W.; Witt, R.; Wood, J.; Wu, J.; Xu, N.; Xu, Q. H.; Xu, Z.; Yepes, P.; Yoo, I.-K.; Yurevich, V. I.; Zhan, W.; Zhang, H.; Zhang, W. M.; Zhang, Y.; Zhang, Z. P.; Zhao, Y.; Zhong, C.; Zoulkarneev, R.; Zoulkarneeva, Y.; Zubarev, A. N.; Zuo, J. X.

2007-11-01

We determine rapidity asymmetry in the production of charged pions, protons, and antiprotons for large transverse momentum (pT) for d+Au collisions at sNN=200 GeV. The rapidity asymmetry is defined as the ratio of particle yields at backward rapidity (Au beam direction) to those at forward rapidity (d beam direction). The identified hadrons are measured in the rapidity regions |y|<0.5 and 0.5<|y|<1.0 for the pT range 2.5

A Novel Surface Plasmon Resonance Biosensor for the Rapid Detection of Botulinum Neurotoxins

PubMed Central

Patel, Kruti; Halevi, Shmuel; Melman, Paul; Schwartz, John; Cai, Shuowei; Singh, Bal Ram

2017-01-01

Botulinum neurotoxins (BoNTs) are Category A agents on the NIAID (National Institute of Allergy and Infectious Diseases) priority pathogen list owing to their extreme toxicity and the relative ease of production. These deadly toxins, in minute quantities (estimated human i.v. lethal dose LD50 of 1–2 ng/kg body weight), cause fatal flaccid paralysis by blocking neurotransmitter release. The current gold standard detection method, the mouse-bioassay, often takes days to confirm botulism. Furthermore, there are no effective antidotes known to reverse the symptoms of botulism, and as a result, patients with severe botulism often require meticulous care during the prolonged paralytic illness. To combat potential bio-terrorism incidents of botulinum neurotoxins, their rapid detection is paramount. Surface plasmon resonance (SPR) is a very sensitive technique to examine bio-molecular interactions. The label-free, real-time analysis, with high sensitivity and low sample consumption makes this technology particularly suitable for detection of the toxin. In this study, we demonstrated the feasibility in an assay with a newly designed SPR instrument for the rapid detection of botulinum neurotoxins. The LOD (limit of detection) of the Newton Photonics (NP) SPR based assay is 6.76 pg/mL for Botulinum Neurotoxin type A Light Chain (BoNT/A LC). We established that the detection sensitivity of the system is comparable to the traditional mouse LD50 bioassay in BoNT/A using this SPR technology. PMID:28783115

Evaluation of a rapid diagnostic test for the detection of Burkholderia pseudomallei in the Lao People's Democratic Republic.

PubMed

Woods, Kate L; Boutthasavong, Latsaniphone; NicFhogartaigh, Caoimhe; Lee, Sue J; Davong, Viengmon; AuCoin, David P; Dance, David A B

2018-05-02

Burkholderia pseudomallei causes significant global morbidity and mortality, with the highest disease burden in parts of Asia where culture-based diagnosis is often not available. We prospectively evaluated the Active Melioidosis Detect (AMD, InBios International, USA) lateral flow immunoassay (LFI) for rapid detection of B. pseudomallei in turbid blood cultures, pus, sputum, sterile fluid, urine, and sera. Performance was compared to B. pseudomallei detection using monoclonal antibody latex agglutination (LA) and immunofluorescence assays (IFA), with culture as the gold standard. AMD was 99% (99/100; 94.6 - 100%) sensitive and 100% (308/308; 98.8-100%) specific on turbid blood culture bottles, with no difference to LA or IFA. AMD specificity was 100% on pus (122/122; 97.0-100%), sputum (20/20; 83.2-100%), and sterile fluid (44/44; 92 - 100%). Sensitivity on these samples was: pus 47.1% (8/17; 23.0 - 72.2%), sputum 33.3% (1/3; 0.84 - 90.6%), and sterile fluid 0% (0/2; 0 - 84.2%). Urine AMD had a positive predictive value of 94% (32/34; 79.7 - 98.5%) for diagnosing melioidosis in our cohort. AMD sensitivity on stored sera, collected prospectively from melioidosis cases during this study, was 13.9% (5/36; 4.7% - 29.5%) when compared to blood culture samples taken on the same day. In conclusion, the AMD is an excellent tool for rapid diagnosis of melioidosis from turbid blood cultures, and maintains specificity across all sample types. It is a promising tool for urinary antigen detection, which could revolutionise diagnosis of melioidosis in resource-limited settings. Further work is required to improve sensitivity on non-blood culture samples. Copyright © 2018 Woods et al.

The rapid transient surveyor

NASA Astrophysics Data System (ADS)

Baranec, C.; Lu, J. R.; Wright, S. A.; Tonry, J.; Tully, R. B.; Szapudi, I.; Takamiya, M.; Hunter, L.; Riddle, R.; Chen, S.; Chun, M.

2016-07-01

The Rapid Transient Surveyor (RTS) is a proposed rapid-response, high-cadence adaptive optics (AO) facility for the UH 2.2-m telescope on Maunakea. RTS will uniquely address the need for high-acuity and sensitive near-infrared spectral follow-up observations of tens of thousands of objects in mere months by combining an excellent observing site, unmatched robotic observational efficiency, and an AO system that significantly increases both sensitivity and spatial resolving power. We will initially use RTS to obtain the infrared spectra of 4,000 Type Ia supernovae identified by the Asteroid Terrestrial-Impact Last Alert System over a two year period that will be crucial to precisely measuring distances and mapping the distribution of dark matter in the z < 0.1 universe. RTS will comprise an upgraded version of the Robo-AO laser AO system and will respond quickly to target-of-opportunity events, minimizing the time between discovery and characterization. RTS will acquire simultaneous-multicolor images with an acuity of 0.07-0.10" across the entire visible spectrum (20% i'-band Strehl in median conditions) and <0.16" in the near infrared, and will detect companions at 0.5" at contrast ratio of 500. The system will include a high-efficiency prism integral field unit spectrograph: R = 70-140 over a total bandpass of 840-1830nm with an 8.7" by 6.0" field of view (0.15" spaxels). The AO correction boosts the infrared point-source sensitivity of the spectrograph against the sky background by a factor of seven for faint targets, giving the UH 2.2-m the H-band sensitivity of a 5.7-m telescope without AO.

Carbon Nanomaterial Based Biosensors for Non-Invasive Detection of Cancer and Disease Biomarkers for Clinical Diagnosis

PubMed Central

Tung, Thanh Tran

2017-01-01

The early diagnosis of diseases, e.g., Parkinson’s and Alzheimer’s disease, diabetes, and various types of cancer, and monitoring the response of patients to the therapy plays a critical role in clinical treatment; therefore, there is an intensive research for the determination of many clinical analytes. In order to achieve point-of-care sensing in clinical practice, sensitive, selective, cost-effective, simple, reliable, and rapid analytical methods are required. Biosensors have become essential tools in biomarker sensing, in which electrode material and architecture play critical roles in achieving sensitive and stable detection. Carbon nanomaterials in the form of particle/dots, tube/wires, and sheets have recently become indispensable elements of biosensor platforms due to their excellent mechanical, electronic, and optical properties. This review summarizes developments in this lucrative field by presenting major biosensor types and variability of sensor platforms in biomedical applications. PMID:28825646

Highly sensitive self-complementary DNA nanoswitches triggered by polyelectrolytes.

PubMed

Wu, Jincai; Yu, Feng; Zhang, Zheng; Chen, Yong; Du, Jie; Maruyama, Atsushi

2016-01-07

Dimerization of two homologous strands of genomic DNA/RNA is an essential feature of retroviral replication. Herein we show that a cationic comb-type copolymer (CCC), poly(L-lysine)-graft-dextran, accelerates the dimerization of self-complementary stem-loop DNA, frequently found in functional DNA/RNA molecules, such as aptamers. Furthermore, an anionic polymer poly(sodium vinylsulfonate) (PVS) dissociates CCC from the duplex shortly within a few seconds. Then single stem-loop DNA spontaneously transforms from its dimer. Thus we can easily control the dimer and stem-loop DNA by switching on/off CCC activity. Both polyelectrolytes and DNA concentrations are in the nanomole per liter range. The polyelectrolyte-assisted transconformation and sequences design strategy ensures the reversible state control with rapid response and effective switching under physiologically relevant conditions. A further application of this sensitive assembly is to construct an aptamer-type drug delivery system, bind or release functional molecules responding to its transconformation.

A sensitive and specific LC-MS/MS method for rapid diagnosis of Niemann-Pick C1 disease from human plasma[S

PubMed Central

Jiang, Xuntian; Sidhu, Rohini; Porter, Forbes D.; Yanjanin, Nicole M.; Speak, Anneliese O.; te Vruchte, Danielle Taylor; Platt, Frances M.; Fujiwara, Hideji; Scherrer, David E.; Zhang, Jessie; Dietzen, Dennis J.; Schaffer, Jean E.; Ory, Daniel S.

2011-01-01

Niemann-Pick type C1 (NPC1) disease is a rare, progressively fatal neurodegenerative disease for which there are no FDA-approved therapies. A major barrier to developing new therapies for this disorder has been the lack of a sensitive and noninvasive diagnostic test. Recently, we demonstrated that two cholesterol oxidation products, specifically cholestane-3β,5α,6β-triol (3β,5α,6β-triol) and 7-ketocholesterol (7-KC), were markedly increased in the plasma of human NPC1 subjects, suggesting a role for these oxysterols in diagnosis of NPC1 disease and evaluation of therapeutics in clinical trials. In the present study, we describe the development of a sensitive and specific LC-MS/MS method for quantifying 3β,5α,6β-triol and 7-KC human plasma after derivatization with N,N-dimethylglycine. We show that dimethylglycine derivatization successfully enhanced the ionization and fragmentation of 3β,5α,6β-triol and 7-KC for mass spectrometric detection of the oxysterol species in human plasma. The oxysterol dimethylglycinates were resolved with high sensitivity and selectivity, and enabled accurate quantification of 3β,5α,6β-triol and 7-KC concentrations in human plasma. The LC-MS/MS assay was able to discriminate with high sensitivity and specificity between control and NPC1 subjects, and offers for the first time a noninvasive, rapid, and highly sensitive method for diagnosis of NPC1 disease. PMID:21518695

Central sensitization as the mechanism underlying pain in joint hypermobility syndrome/Ehlers-Danlos syndrome, hypermobility type.

PubMed

Di Stefano, G; Celletti, C; Baron, R; Castori, M; Di Franco, M; La Cesa, S; Leone, C; Pepe, A; Cruccu, G; Truini, A; Camerota, F

2016-09-01

Patients with joint hypermobility syndrome/Ehlers-Danlos syndrome, hypermobility type (JHS/EDS-HT) commonly suffer from pain. How this hereditary connective tissue disorder causes pain remains unclear although previous studies suggested it shares similar mechanisms with neuropathic pain and fibromyalgia. In this prospective study seeking information on the mechanisms underlying pain in patients with JHS/EDS-HT, we enrolled 27 consecutive patients with this connective tissue disorder. Patients underwent a detailed clinical examination, including the neuropathic pain questionnaire DN4 and the fibromyalgia rapid screening tool. As quantitative sensory testing methods, we included thermal-pain perceptive thresholds and the wind-up ratio and recorded a standard nerve conduction study to assess non-nociceptive fibres and laser-evoked potentials, assessing nociceptive fibres. Clinical examination and diagnostic tests disclosed no somatosensory nervous system damage. Conversely, most patients suffered from widespread pain, the fibromyalgia rapid screening tool elicited positive findings, and quantitative sensory testing showed lowered cold and heat pain thresholds and an increased wind-up ratio. While the lack of somatosensory nervous system damage is incompatible with neuropathic pain as the mechanism underlying pain in JHS/EDS-HT, the lowered cold and heat pain thresholds and increased wind-up ratio imply that pain in JHS/EDS-HT might arise through central sensitization. Hence, this connective tissue disorder and fibromyalgia share similar pain mechanisms. WHAT DOES THIS STUDY ADD?: In patients with JHS/EDS-HT, the persistent nociceptive input due to joint abnormalities probably triggers central sensitization in the dorsal horn neurons and causes widespread pain. © 2016 European Pain Federation - EFIC®

Rapid detection of porcine circovirus type 2 using a TaqMan-based real-time PCR.

PubMed

Zhao, Kai; Han, Fangting; Zou, Yong; Zhu, Lianlong; Li, Chunhua; Xu, Yan; Zhang, Chunling; Tan, Furong; Wang, Jinbin; Tao, Shiru; He, Xizhong; Zhou, Zongqing; Tang, Xueming

2010-12-31

Porcine circovirus type 2 (PCV2) and the associated disease postweaning multisystemic wasting syndrome (PMWS) have caused heavy losses in global agriculture in recent decades. Rapid detection of PCV2 is very important for the effective prophylaxis and treatment of PMWS. To establish a sensitive, specific assay for the detection and quantitation of PCV2, we designed and synthesized specific primers and a probe in the open reading frame 2. The assay had a wide dynamic range with excellent linearity and reliable reproducibility, and detected between 102 and 1010 copies of the genomic DNA per reaction. The coefficient of variation for Ct values varied from 0.59% to 1.05% in the same assay and from 1.9% to 4.2% in 10 different assays. The assay did not cross-react with porcine circovirus type 1, porcine reproductive and respiratory, porcine epidemic diarrhea, transmissible gastroenteritis of pigs and rotavirus. The limits of detection and quantitation were 10 and 100 copies, respectively. Using the established real-time PCR system, 39 of the 40 samples we tested were detected as positive.

Physical activity into the meal glucose-insulin model of type 1 diabetes: in silico studies.

PubMed

Man, Chiara Dalla; Breton, Marc D; Cobelli, Claudio

2009-01-01

A simulation model of a glucose-insulin system accounting for physical activity is needed to reliably simulate normal life conditions, thus accelerating the development of an artificial pancreas. In fact, exercise causes a transient increase of insulin action and may lead to hypoglycemia. However, physical activity is difficult to model. In the past, it was described indirectly as a rise in insulin. Recently, a new parsimonious model of exercise effect on glucose homeostasis has been proposed that links the change in insulin action and glucose effectiveness to heart rate (HR). The aim of this study was to plug this exercise model into our recently proposed large-scale simulation model of glucose metabolism in type 1 diabetes to better describe normal life conditions. The exercise model describes changes in glucose-insulin dynamics in two phases: a rapid on-and-off change in insulin-independent glucose clearance and a rapid-on/slow-off change in insulin sensitivity. Three candidate models of glucose effectiveness and insulin sensitivity as a function of HR have been considered, both during exercise and recovery after exercise. By incorporating these three models into the type 1 diabetes model, we simulated different levels (from mild to moderate) and duration of exercise (15 and 30 minutes), both in steady-state (e.g., during euglycemic-hyperinsulinemic clamp) and in nonsteady state (e.g., after a meal) conditions. One candidate exercise model was selected as the most reliable. A type 1 diabetes model also describing physical activity is proposed. The model represents a step forward to accurately describe glucose homeostasis in normal life conditions; however, further studies are needed to validate it against data. © Diabetes Technology Society

Identification of Haemophilus influenzae Type b Isolates by Use of Matrix-Assisted Laser Desorption Ionization-Time of Flight Mass Spectrometry.

PubMed

Månsson, Viktor; Resman, Fredrik; Kostrzewa, Markus; Nilson, Bo; Riesbeck, Kristian

2015-07-01

Haemophilus influenzae type b (Hib) is, in contrast to non-type b H. influenzae, associated with severe invasive disease, such as meningitis and epiglottitis, in small children. To date, accurate H. influenzae capsule typing requires PCR, a time-consuming and cumbersome method. Matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) provides rapid bacterial diagnostics and is increasingly used in clinical microbiology laboratories. Here, MALDI-TOF MS was evaluated as a novel approach to separate Hib from other H. influenzae. PCR-verified Hib and non-Hib reference isolates were selected based on genetic and spectral characteristics. Mass spectra of reference isolates were acquired and used to generate different classification algorithms for Hib/non-Hib differentiation using both ClinProTools and the MALDI Biotyper software. A test series of mass spectra from 33 Hib and 77 non-Hib isolates, all characterized by PCR, was used to evaluate the algorithms. Several algorithms yielded good results, but the two best were a ClinProTools model based on 22 separating peaks and subtyping main spectra (MSPs) using MALDI Biotyper. The ClinProTools model had a sensitivity of 100% and a specificity of 99%, and the results were 98% reproducible using a different MALDI-TOF MS instrument. The Biotyper subtyping MSPs had a sensitivity of 97%, a specificity of 100%, and 93% reproducibility. Our results suggest that it is possible to use MALDI-TOF MS to differentiate Hib from other H. influenzae. This is a promising method for rapidly identifying Hib in unvaccinated populations and for the screening and surveillance of Hib carriage in vaccinated populations. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

Mouse Embryo Cryopreservation by Rapid Cooling.

PubMed

Shaw, Jillian

2018-05-01

Embryo cryopreservation has been used to archive mouse strains. Protocols have evolved over this time and now vary considerably in terms of cryoprotectant solution, cooling and warming rates, methods to add and remove cryoprotectant, container or carrier type, volume of cryoprotectant, the stage of preimplantation development, and the use of additional treatments such as blastocyst puncture and microinjection. The rapid cooling methods use concentrated solutions of cryoprotectants to reduce the water content of the cell before cooling commences, thus preventing the formation of ice crystals. Embryos are equilibrated with the cryoprotectants, loaded into a carrier, and then rapidly cooled (e.g., by being plunged directly into LN 2 or onto a surface cooled in LN 2 ). The rapid cooling methods eliminate the need for controlled-rate freezers and seeding procedures. However, they are much more sensitive to minor variations when performing the steps. The rapid-cooling protocol described here is suitable for use with plastic insemination straws. Because it uses relatively large volumes, it is less technically demanding than some other methods that use minivolume devices. © 2018 Cold Spring Harbor Laboratory Press.

Eradication of bovine tuberculosis at a herd-level in Madrid, Spain: study of within-herd transmission dynamics over a 12 year period

PubMed Central

2012-01-01

Background Eradication of bovine tuberculosis (bTB) through the application of test-and-cull programs is a declared goal of developed countries in which the disease is still endemic. Here, longitudinal data from more than 1,700 cattle herds tested during a 12 year-period in the eradication program in the region of Madrid, Spain, were analyzed to quantify the within-herd transmission coefficient (β) depending on the herd-type (beef/dairy/bullfighting). In addition, the probability to recover the officially bTB free (OTF) status in infected herds depending on the type of herd and the diagnostic strategy implemented was assessed using Cox proportional hazard models. Results Overall, dairy herds showed higher β (median 4.7) than beef or bullfighting herds (2.3 and 2.2 respectively). Introduction of interferon-gamma (IFN-γ) as an ancillary test produced an apparent increase in the β coefficient regardless of production type, likely due to an increase in diagnostic sensitivity. Time to recover OTF status was also significantly lower in dairy herds, and length of bTB episodes was significantly reduced when the IFN-γ was implemented to manage the outbreak. Conclusions Our results suggest that bTB spreads more rapidly in dairy herds compared to other herd types, a likely cause being management and demographic-related factors. However, outbreaks in dairy herds can be controlled more rapidly than in typically extensive herd types. Finally, IFN-γ proved its usefulness to rapidly eradicate bTB at a herd-level. PMID:22748007

Development of VHH antibodies against dengue virus type 2 NS1 and comparison with monoclonal antibodies for use in immunological diagnosis.

PubMed

Fatima, Aneela; Wang, Haiying; Kang, Keren; Xia, Liliang; Wang, Ying; Ye, Wei; Wang, Jufang; Wang, Xiaoning

2014-01-01

The possibility of using variable domain heavy-chain antibodies (VHH antibodies) as diagnostic tools for dengue virus (DENV) type 2 NS1 protein was investigated and compared with the use of conventional monoclonal antibodies. After successful expression of DENV type 2 NS1 protein, the genes of VHH antibodies against NS1 protein were biopanned from a non-immune llama library by phage display. VHH antibodies were then expressed and purified from Escherichia coli. Simultaneously, monoclonal antibodies were obtained by the conventional route. Sequence analysis of the VHH antibodies revealed novel and long complementarity determining regions 3 (CDR3). Epitope mapping was performed via a phage display peptide library using purified VHH and monoclonal antibodies as targets. Interestingly, the same region of NS1, which comprises amino acids 224HWPKPHTLW232, was conserved for both kinds of antibodies displaying the consensus motif histidine-tryptophan-tryptophan or tryptophan-proline-tryptophan. The two types of antibodies were used to prepare rapid diagnostic kits based on immunochromatographic assay. The VHH antibody immobilized rapid diagnostic kit showed better sensitivity and specificity than the monoclonal antibody immobilized rapid diagnostic kit, which might be due to the long CDR3 regions of the VHH antibodies and their ability to bind to the pocket and cleft of the targeted antigen. This demonstrates that VHH antibodies are likely to be an option for developing point-of-care tests against DENV infection.

Development of VHH Antibodies against Dengue Virus Type 2 NS1 and Comparison with Monoclonal Antibodies for Use in Immunological Diagnosis

PubMed Central

Fatima, Aneela; Wang, Haiying; Kang, Keren; Xia, Liliang; Wang, Ying; Ye, Wei; Wang, Jufang; Wang, Xiaoning

2014-01-01

The possibility of using variable domain heavy-chain antibodies (VHH antibodies) as diagnostic tools for dengue virus (DENV) type 2 NS1 protein was investigated and compared with the use of conventional monoclonal antibodies. After successful expression of DENV type 2 NS1 protein, the genes of VHH antibodies against NS1 protein were biopanned from a non-immune llama library by phage display. VHH antibodies were then expressed and purified from Escherichia coli. Simultaneously, monoclonal antibodies were obtained by the conventional route. Sequence analysis of the VHH antibodies revealed novel and long complementarity determining regions 3 (CDR3). Epitope mapping was performed via a phage display peptide library using purified VHH and monoclonal antibodies as targets. Interestingly, the same region of NS1, which comprises amino acids 224HWPKPHTLW232, was conserved for both kinds of antibodies displaying the consensus motif histidine-tryptophan-tryptophan or tryptophan-proline-tryptophan. The two types of antibodies were used to prepare rapid diagnostic kits based on immunochromatographic assay. The VHH antibody immobilized rapid diagnostic kit showed better sensitivity and specificity than the monoclonal antibody immobilized rapid diagnostic kit, which might be due to the long CDR3 regions of the VHH antibodies and their ability to bind to the pocket and cleft of the targeted antigen. This demonstrates that VHH antibodies are likely to be an option for developing point-of-care tests against DENV infection. PMID:24751715

The art of maturity modeling. Part 2. Alternative models and sensitivity analysis

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

Waples, D.W.; Suizu, Masahiro; Kamata, Hiromi

1992-01-01

The sensitivity of exploration decisions to variations in several input parameters for maturity modeling was examined for the MITI Rumoi well, Hokkaido, Japan. Decisions were almost completely insensitive to uncertainties about formation age and erosional removal across some unconformities, but were more sensitive to changes in removal during unconformities which occurred near maximum paleotemperatures. Exploration decisions were not very sensitive to the choice of a particular kinetic model for hydrocarbon generation. Uncertainties in kerogen type and the kinetics of different kerogen types are more serious than differences among the various kinetic models. Results of modeling using the TTI method weremore » unsatisfactory. Thermal history and timing and amount of hydrocarbon generation estimated or calculated using the TTI method were greatly different from those obtained using a purely kinetic model. The authors strongly recommend use of the kinetic R{sub o} method instead of the TTI method. If they had lacked measured R{sub o} data, subsurface temperature data, or both, their confidence in the modeling results would have been sharply reduced. Conceptual models for predicting heat flow and thermal conductivity are simply too weak at present to allow one to carry out highly meaningful modeling unless the input is constrained by measured data. Maturity modeling therefore requires the use of more, not fewer, measured temperature and maturity data. The use of sensitivity analysis in maturity modeling is very important for understanding the geologic system, for knowing what level of confidence to place on the results, and for determining what new types of data would be most necessary to improve confidence. Sensitivity analysis can be carried out easily using a rapid, interactive maturity-modeling program.« less

Detection of pseudorabies virus by duplex droplet digital PCR assay.

PubMed

Ren, Meishen; Lin, Hua; Chen, Shijie; Yang, Miao; An, Wei; Wang, Yin; Xue, Changhua; Sun, Yinjie; Yan, Yubao; Hu, Juan

2018-01-01

Aujeszky's disease, caused by pseudorabies virus (PRV), has damaged the economy of the Chinese swine industry. A large number of PRV gene-deleted vaccines have been constructed based on deletion of the glycoprotein E ( gE) gene combined with other virulence-related gene deletions, such as thymidine kinase ( TK), whereas PRV wild-type strains contain an intact gE gene. We developed a sensitive duplex droplet digital PCR (ddPCR) assay to rapidly detect PRV wild-type isolates and gE gene-deleted viral vaccines. We compared this assay with a TaqMan real-time PCR (qPCR) using the same primers and probes. Both assays exhibited good linearity and repeatability; however, ddPCR maintained linearity at extremely low concentrations, whereas qPCR did not. Based on positive results for both gE and gB, the detection limit of ddPCR was found to be 4.75 copies/µL in contrast of 76 copies/µL for qPCR, showing that ddPCR provided a 16-fold improvement in sensitivity. In addition, no nonspecific amplification was shown in specificity testing, and the PRV wild-type was distinguished from a gE-deleted strain. The ddPCR was more sensitive when analyzing clinical serum samples. Thus, ddPCR may become an appropriate detection platform for PRV.

Performance of Four Transport and Storage Systems for Molecular Detection of Multidrug-Resistant Tuberculosis

PubMed Central

Rabodoarivelo, Marie Sylvianne; Imperiale, Bélen; andrianiavomikotroka, Rina; Brandao, Angela; Kumar, Parveen; Singh, Sarman; Ferrazoli, Lucilaine; Morcillo, Nora; Rasolofo, Voahangy; Palomino, Juan Carlos; Vandamme, Peter; Martin, Anandi

2015-01-01

Background Detection of drug-resistant tuberculosis is essential for the control of the disease but it is often hampered by the limitation of transport and storage of samples from remote locations to the reference laboratory. We performed a retrospective field study to evaluate the performance of four supports enabling the transport and storage of samples to be used for molecular detection of drug resistance using the GenoType MTBDRplus. Methods Two hundred Mycobacterium tuberculosis strains were selected and spotted on slides, FTA cards, GenoCards, and in ethanol. GenoType MTBDRplus was subsequently performed with the DNA extracted from these supports. Sensitivity and specificity were calculated and compared to the results obtained by drug susceptibility testing. Results For all supports, the overall sensitivity and specificity for detection of resistance to RIF was between 95% and 100%, and for INH between 95% and 98%. Conclusion The four transport and storage supports showed a good sensitivity and specificity for the detection of resistance to RIF and INH in M. tuberculosis strains using the GenoType MTBDRplus. These supports can be maintained at room temperature and could represent an important alternative cost-effective method useful for rapid molecular detection of drug-resistant TB in low-resource settings. PMID:26431352

Microbiological diagnosis and molecular typing of Legionella strains during an outbreak of legionellosis in Southern Germany.

PubMed

Essig, Andreas; von Baum, Heike; Gonser, Theodor; Haerter, Georg; Lück, Christian

2016-02-01

An explosive outbreak of Legionnaires' disease with 64 reported cases occurred in Ulm/Neu-Ulm in the South of Germany in December 2009/January 2010 caused by Legionella (L.) pneumophila serogroup 1, monoclonal (mAb) subtype Knoxville, sequence type (ST) 62. Here we present the clinical microbiological results from 51 patients who were diagnosed at the University hospital of Ulm, the results of the environmental investigations and of molecular typing of patients and environmental strains. All 50 patients from whom urine specimens were available were positive for L. pneumophila antigen when an enzyme-linked immunosorbent assay (EIA) was used following concentration of those urine samples that tested initially negative. The sensitivity of the BinaxNow rapid immunographic assay (ICA), after 15 min reading and after 60 min reading were 70% and 84%, respectively. Direct typing confirmed the monoclonal subtype Knoxville in 5 out of 8 concentrated urine samples. Real time PCR testing of respiratory tract specimens for L. pneumophila was positive in 15 out of 25 (60%) patients. Direct nested sequence based typing (nSBT) in some of these samples allowed partial confirmation of ST62. L. pneumophila serogroup 1, monoclonal subtype Knoxville ST62, defined as the epidemic strain was isolated from 8 out of 31 outbreak patients (26%) and from one cooling tower confirming it as the most likely source of the outbreak. While rapid detection of Legionella antigenuria was crucial for the recognition and management of the outbreak, culture and molecular typing of the strains from patients and environmental specimens was the clue for the rapid identification of the source of infection. Copyright © 2016 Elsevier GmbH. All rights reserved.

Role of intraoperative imprint cytology in diagnosis of suspected ovarian neoplasms.

PubMed

Dey, Soumit; Misra, Vatsala; Singh, P A; Mishra, Sanjay; Sharma, Nishant

2010-01-01

The present study was conducted to assess whether cytology can help in rapid diagnosis of ovarian neoplasms and thus facilitate individualised treatment. A prospective investigation was performed on 30 cases of suspected ovarian neoplasms. Imprint smears were made intraperatively from fresh samples from various representative areas, and stained with Leishman Giemsa for air-dried smears, and with hematoxylin and eosin and Papanicolaou for alcohol-fixed smears. A rapid opinion regarding the benign or malignant nature of the lesion and the type of tumour was given. The overall sensitivity was 96.2%, specificity 75%, positive predictive value 96.3%, and diagnostic accuracy of 83.3%. Characteristic cytological patterns were noted in various epithelial and germ cell tumours. Imprint cytology can be used as an adjunct to histopathology for rapid and early diagnosis in the operation theatre, thus helping better management of patients.

Development of an immunochromatographic kit for rapid detection of human influenza B virus infection.

PubMed

Zhang, Peirui; Duan, Yueqiang; Zhang, Dexi; Zhang, Shaogeng; Li, Zhiwei; Wang, Xiliang; Yang, Penghui

2014-01-01

Type B influenza virus is a major epidemic strain responsible for considerable mortality and morbidity. A colloidal gold immunochromatographic strip for the rapid detection of human influenza B virus was developed. This test is based on membrane chromatography and uses colloidal gold conjugated with influenza B virus anti-NP monoclonal antibody as the tracer. The assembled test strip was housed in a plastic case. The colloid gold strip (CGS) specifically detected all influenza B viruses tested and did not react with other respiratory viruses. Compared with SYBR Green real-time PCR, the sensitivity and specificity of the CGS test was 89.76% and 99.56%, respectively, and the consistency ratio between CGS and real-time PCR was 96.06% in detecting influenza B virus in 710 nasopharyngeal swabs from patients with influenza-like illness in the hospital. The CGS array developed in this study enabled typing of influenza B viruses in human clinical specimens. Thus, together with the advantages of rapid detection and easy operation without requiring specialized personnel and equipment, this technique is a convenient and relatively inexpensive diagnostic tool for large-scale screening of clinical samples.

An assay for evoked locomotor behavior in Drosophila reveals a role for integrins in ethanol sensitivity and rapid ethanol tolerance.

PubMed

Bhandari, Poonam; Kendler, Kenneth S; Bettinger, Jill C; Davies, Andrew G; Grotewiel, Mike

2009-10-01

Ethanol induces similar behavioral responses in mammals and the fruit fly, Drosophila melanogaster. By coupling assays for ethanol-related behavior to the genetic tools available in flies, a number of genes have been identified that influence physiological responses to ethanol. To enhance the utility of the Drosophila model for investigating genes involved in ethanol-related behavior, we explored the value of an assay that measures the sedative effects of ethanol on negative geotaxis, an evoked locomotor response. We established eRING (ethanol Rapid Iterative Negative Geotaxis) as an assay for quantitating the sedative effects of ethanol on negative geotaxis (i.e., startle-induced climbing). We validated the assay by assessing acute sensitivity to ethanol and rapid ethanol tolerance in several different control strains and in flies with mutations known to disrupt these behaviors. We also used eRING in a candidate screen to identify mutants with altered ethanol-related behaviors. Negative geotaxis measured in eRING assays was dose-dependently impaired by ethanol exposure. Flies developed tolerance to the intoxicating effects of ethanol when tested during a second exposure. Ethanol sensitivity and rapid ethanol tolerance varied across 4 control strains, but internal ethanol concentrations were indistinguishable in the 4 strains during a first and second challenge with ethanol. Ethanol sensitivity and rapid ethanol tolerance, respectively, were altered in flies with mutations in amnesiac and hangover, genes known to influence these traits. Additionally, mutations in the beta integrin gene myospheroid and the alpha integrin gene scab increased the initial sensitivity to ethanol and enhanced the development of rapid ethanol tolerance without altering internal ethanol concentrations. The eRING assay is suitable for investigating genetic mechanisms that influence ethanol sensitivity and rapid ethanol tolerance. Ethanol sensitivity and rapid ethanol tolerance depend on the function of alpha and beta integrins in flies.

Sensitivity of Rabbit Ventricular Action Potential and Ca2+ Dynamics to Small Variations in Membrane Currents and Ion Diffusion Coefficients

PubMed Central

Lo, Yuan Hung; Peachey, Tom; Abramson, David; McCulloch, Andrew

2013-01-01

Little is known about how small variations in ionic currents and Ca2+ and Na+ diffusion coefficients impact action potential and Ca2+ dynamics in rabbit ventricular myocytes. We applied sensitivity analysis to quantify the sensitivity of Shannon et al. model (Biophys. J., 2004) to 5%–10% changes in currents conductance, channels distribution, and ion diffusion in rabbit ventricular cells. We found that action potential duration and Ca2+ peaks are highly sensitive to 10% increase in L-type Ca2+ current; moderately influenced by 10% increase in Na+-Ca2+ exchanger, Na+-K+ pump, rapid delayed and slow transient outward K+ currents, and Cl− background current; insensitive to 10% increases in all other ionic currents and sarcoplasmic reticulum Ca2+ fluxes. Cell electrical activity is strongly affected by 5% shift of L-type Ca2+ channels and Na+-Ca2+ exchanger in between junctional and submembrane spaces while Ca2+-activated Cl−-channel redistribution has the modest effect. Small changes in submembrane and cytosolic diffusion coefficients for Ca2+, but not in Na+ transfer, may alter notably myocyte contraction. Our studies highlight the need for more precise measurements and further extending and testing of the Shannon et al. model. Our results demonstrate usefulness of sensitivity analysis to identify specific knowledge gaps and controversies related to ventricular cell electrophysiology and Ca2+ signaling. PMID:24222910

Ozone-Sensitive Arabidopsis Mutants with Deficiencies in Photorespiratory Enzymes.

PubMed

Saji, Shoko; Bathula, Srinivas; Kubo, Akihiro; Tamaoki, Masanori; Aono, Mitsuko; Sano, Tomoharu; Tobe, Kazuo; Timm, Stefan; Bauwe, Hermann; Nakajima, Nobuyoshi; Saji, Hikaru

2017-05-01

An ozone-sensitive mutant was isolated from T-DNA-tagged lines of Arabidopsis thaliana. The T-DNA was inserted at a locus on chromosome 3, where two genes encoding glycolate oxidases, GOX1 and GOX2, peroxisomal enzymes involved in photorespiration, reside contiguously. The amounts of the mutant's foliar transcripts for these genes were reduced, and glycolate oxidase activity was approximately 60% of that of the wild-type plants. No difference in growth and appearance was observed between the mutant and the wild-type plants under normal conditions with ambient air under a light intensity of 100 µmol photons m-2 s-1. However, signs of severe damage, such as chlorosis and ion leakage from the tissue, rapidly appeared in mutant leaves in response to ozone treatment at a concentration of 0.2 µl l-1 under a higher light intensity of 350 µmol photons m-2 s-1 that caused no such symptoms in the wild-type plant. The mutant also exhibited sensitivity to sulfur dioxide and long-term high-intensity light. Arabidopsis mutants with deficiencies in other photorespiratory enzymes such as glutamate:glyoxylate aminotransferase and hydroxypyruvate reductase also exhibited ozone sensitivities. Therefore, photorespiration appears to be involved in protection against photooxidative stress caused by ozone and other abiotic factors under high-intensity light. © The Author 2017. Published by Oxford University Press on behalf of Japanese Society of Plant Physiologists. All rights reserved. For permissions, please email: journals.permissions@oup.com.

Accurate and fast creep test for viscoelastic fluids using disk-probe-type and quadrupole-arrangement-type electromagnetically spinning systems

NASA Astrophysics Data System (ADS)

Hirano, Taichi; Sakai, Keiji

2017-07-01

Viscoelasticity is a unique characteristic of soft materials and describes its dynamic response to mechanical stimulations. A creep test is an experimental method for measuring the strain ratio/rate against an applied stress, thereby assessing the viscoelasticity of the materials. We propose two advanced experimental systems suitable for the creep test, adopting our original electromagnetically spinning (EMS) technique. This technique can apply a constant torque by a noncontact mechanism, thereby allowing more sensitive and rapid measurements. The viscosity and elasticity of a semidilute wormlike micellar solution were determined using two setups, and the consistency between the results was assessed.

[Studies of bacterial typing with MALDI-TOF].

PubMed

Culebras, Esther; Alvarez-Buylla, Adela; Jose Artacho Reinoso, M; Antonio Lepe, Jose

2016-06-01

MALDI-TOF (matrix-assisted laser desorption ionization time-of-flight) mass spectrometry has emerged as a potential tool for microbial characterization and identification in many microbiology departments. The technology is rapid, sensitive, and relatively inexpensive in terms of both the labour and costs involved. This review provides an overview on its utility for strain typing and epidemiological studies and explains the methodological approaches that can be used both for the performance of the technique and for the analysis of results. Finally, the review summarizes studies on the characterization of distinct bacterial species. Copyright © 2016 Elsevier España, S.L.U. All rights reserved.

The failure of routine rapid HIV testing: a case study of improving low sensitivity in the field.

PubMed

Wolpaw, Benjamin J; Mathews, Catherine; Chopra, Mickey; Hardie, Diana; de Azevedo, Virginia; Jennings, Karen; Lurie, Mark N

2010-03-22

The rapid HIV antibody test is the diagnostic tool of choice in low and middle-income countries. Previous evidence suggests that rapid HIV diagnostic tests may underperform in the field, failing to detect a substantial number of infections. A research study inadvertently discovered that a clinic rapid HIV testing process was failing to detect cases of established (high antibody titer) infection, exhibiting an estimated 68.7% sensitivity (95% CI [41.3%-89.0%]) over the course of the first three weeks of observation. The setting is a public service clinic that provides STI diagnosis and treatment in an impoverished, peri-urban community outside of Cape Town, South Africa. The researchers and local health administrators collaborated to investigate the cause of the poor test performance and make necessary corrections. The clinic changed the brand of rapid test being used and later introduced quality improvement measures. Observations were made of the clinic staff as they administered rapid HIV tests to real patients. Estimated testing sensitivity was calculated as the number of rapid HIV test positive individuals detected by the clinic divided by this number plus the number of PCR positive, highly reactive 3rd generation ELISA patients identified among those who were rapid test negative at the clinic. In the period of five months after the clinic made the switch of rapid HIV tests, estimated sensitivity improved to 93.5% (95% CI [86.5%-97.6%]), during which time observations of counselors administering tests at the clinic found poor adherence to the recommended testing protocol. Quality improvement measures were implemented and estimated sensitivity rose to 95.1% (95% CI [83.5%-99.4%]) during the final two months of full observation. Poor testing procedure in the field can lead to exceedingly low levels of rapid HIV test sensitivity, making it imperative that stringent quality control measures are implemented where they do not already exist. Certain brands of rapid-testing kits may perform better than others when faced with sub-optimal use.

Radioimmunoassay measurement of creatine kinase bb in the serum of schizophrenic patients

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

Lerner, M.H.; Friedhoff, A.J.

1980-03-03

Brain type creatine kinase (BB) isoenzyme was measured using a highly sensitive and specific radioimmunoassay procedure in two schizophrenic populations. The data would indicate that in the schizophrenic populations examined there is insufficient tissue disruption to cause abnormal build-up of brain creatine kinase levels. However the possibility of a rapid removal of creatine kinase BB from the circulation exists. The elevated creatine kinase reported in acute schizophrenics is most likely not of brain origin.

[Differentiation of influenza (Flu) type A, type B, and respiratory syncytial virus (RSV) by QuickNavi™-Flu+RSV].

PubMed

Kohiyama, Risa; Miyazawa, Takashi; Shibano, Nobuko; Inano, Koichi

2014-01-01

Because it is not easy to differentiate Influenza virus (Flu) from RS virus (RSV) just by clinical symptoms, to accurately diagnose those viruses in conjunction with patient's clinical symptoms, rapid diagnostic kits has been used separately for each of those viruses. In our new study, we have developed a new rapid diagnostic kit, QuickNavi™-Flu+RSV. The kit can detect Flu A, Flu B, and RSV antigens with a single sample collection and an assay. Total of 2,873 cases (including nasopharyngeal swabs and nasopharyngeal aspirates specimens) in 2010/2011 and 2011/2012 seasons were evaluated with QuickNavi™-Flu+RSV and a commercially available kit. Sensitivity, specificity, and accuracy of Flu type A, type B, and RSV were above 95% when compared to commercially available kits (QuickNavi™-Flu and QuickNavi™-RSV) and considered to be equivalent to the commercially available kits. In 2011/2012 season, RSV infections increased prior to Flu season and continued during the peak of the Flu season. The kit can contribute to accurate diagnosis of Flu and RSV infections since co-infection cases have also been reported during the 2011/2012 season. QuickNavi™-Flu+RSV is useful for differential diagnosis of respiratory infectious diseases since it can detect Flu type A, type B, and RSV virus antigens with a single sample collection.

Diagnostic tools based on minor groove binder probe technology for rapid identification of vaccinal and field strains of canine parvovirus type 2b.

PubMed

Decaro, Nicola; Martella, Vito; Elia, Gabriella; Desario, Costantina; Campolo, Marco; Buonavoglia, Domenico; Bellacicco, Anna Lucia; Tempesta, Maria; Buonavoglia, Canio

2006-12-01

TaqMan-based diagnostic tests have been developed for the identification of canine parvovirus type 2 (CPV-2) strains in the faeces of dogs with diarrhoea, including a minor groove binder (MGB) probe assay for identification of type 2-based vaccines and field strains (types 2a, 2b and 2c). Since type 2b vaccines have been licensed recently in Europe, two novel MGB assays were developed for discrimination between type 2b vaccines and field strains of CPV. Such assays have been found to be highly sensitive, specific and reproducible, allowing for simultaneous detection of type 2b vaccinal and field strains present in the same specimens. These new assays will help resolution of the diagnostic problems related to the detection of a type 2b strain in the faeces of dogs shortly after the administration of a type 2b vaccine.

Highly Sensitive Bacteriophage-Based Detection of Brucella abortus in Mixed Culture and Spiked Blood

PubMed Central

Sergueev, Kirill V.; Filippov, Andrey A.; Nikolich, Mikeljon P.

2017-01-01

For decades, bacteriophages (phages) have been used for Brucella species identification in the diagnosis and epidemiology of brucellosis. Traditional Brucella phage typing is a multi-day procedure including the isolation of a pure culture, a step that can take up to three weeks. In this study, we focused on the use of brucellaphages for sensitive detection of the pathogen in clinical and other complex samples, and developed an indirect method of Brucella detection using real-time quantitative PCR monitoring of brucellaphage DNA amplification via replication on live Brucella cells. This assay allowed the detection of single bacteria (down to 1 colony-forming unit per milliliter) within 72 h without DNA extraction and purification steps. The technique was equally efficient with Brucella abortus pure culture and with mixed cultures of B. abortus and α-proteobacterial near neighbors that can be misidentified as Brucella spp., Ochrobactrum anthropi and Afipia felis. The addition of a simple short sample preparation step enabled the indirect phage-based detection of B. abortus in spiked blood, with the same high sensitivity. This indirect phage-based detection assay enables the rapid and sensitive detection of live B. abortus in mixed cultures and in blood samples, and can potentially be applied for detection in other clinical samples and other complex sample types. PMID:28604602

[Identification of hepatitis B virus YMDD point mutation using peptide nucleic acid clamping PCR].

PubMed

Zhang, Yingying; He, Haitang; Yang, Jie; Hou, Jinlin

2013-06-01

To establish a peptide nucleic acid clamping PCR assay for detecting hepatitis B virus (HBV) drug resistance mutation. RtM204I (ATT) mutant, rtM204V (GTG) mutant and rtM204 (ATG) wild-type plasmids mixed at different ratios were detected for mutations by PNA clamping PCR assay and direct sequencing, and the sensitivity and specificity of the two methods were compared. Serum samples from 85 patients with chronic HBV infection were detected for drug resistance using the two methods. The sensitivity of PNA-PCR assay was 0.001% in a 10(5)-fold excess of wild-type HBV DNA with a detection limit of 10(1) copies. The sensitivity of direct sequencing was 10% with a detection limit of 10(4) copies. Mutants were detected in 73 of the 85 serum samples (85.9%), including YIDD in 40 samples, YVDD in 23 samples, and YIDD+YVDD in 10 samples. The agreement of PNA-PCR assay with direct sequencing was only 40% (34/85, YIDD in 21 samples, YVDD in 11 samples, and YIDD+YVDD in 2 samples). Neither of the two methods yielded positive results for the negative control samples, suggesting their good specificity. PNA-PCR assay appears to be a more sensitive and rapid assay for detection of HBV genotypic resistance.

Human dopamine receptor nanovesicles for gate-potential modulators in high-performance field-effect transistor biosensors

NASA Astrophysics Data System (ADS)

Park, Seon Joo; Song, Hyun Seok; Kwon, Oh Seok; Chung, Ji Hyun; Lee, Seung Hwan; An, Ji Hyun; Ahn, Sae Ryun; Lee, Ji Eun; Yoon, Hyeonseok; Park, Tai Hyun; Jang, Jyongsik

2014-03-01

The development of molecular detection that allows rapid responses with high sensitivity and selectivity remains challenging. Herein, we demonstrate the strategy of novel bio-nanotechnology to successfully fabricate high-performance dopamine (DA) biosensor using DA Receptor-containing uniform-particle-shaped Nanovesicles-immobilized Carboxylated poly(3,4-ethylenedioxythiophene) (CPEDOT) NTs (DRNCNs). DA molecules are commonly associated with serious diseases, such as Parkinson's and Alzheimer's diseases. For the first time, nanovesicles containing a human DA receptor D1 (hDRD1) were successfully constructed from HEK-293 cells, stably expressing hDRD1. The nanovesicles containing hDRD1 as gate-potential modulator on the conducting polymer (CP) nanomaterial transistors provided high-performance responses to DA molecule owing to their uniform, monodispersive morphologies and outstanding discrimination ability. Specifically, the DRNCNs were integrated into a liquid-ion gated field-effect transistor (FET) system via immobilization and attachment processes, leading to high sensitivity and excellent selectivity toward DA in liquid state. Unprecedentedly, the minimum detectable level (MDL) from the field-induced DA responses was as low as 10 pM in real- time, which is 10 times more sensitive than that of previously reported CP based-DA biosensors. Moreover, the FET-type DRNCN biosensor had a rapid response time (<1 s) and showed excellent selectivity in human serum.

Facilitation of Allergic Sensitization and Allergic Airway Inflammation by Pollen-Induced Innate Neutrophil Recruitment

PubMed Central

Hosoki, Koa; Aguilera-Aguirre, Leopoldo; Brasier, Allan R.; Kurosky, Alexander; Boldogh, Istvan

2016-01-01

Neutrophil recruitment is a hallmark of rapid innate immune responses. Exposure of airways of naive mice to pollens rapidly induces neutrophil recruitment. The innate mechanisms that regulate pollen-induced neutrophil recruitment and the contribution of this neutrophilic response to subsequent induction of allergic sensitization and inflammation need to be elucidated. Here we show that ragweed pollen extract (RWPE) challenge in naive mice induces C-X-C motif ligand (CXCL) chemokine synthesis, which stimulates chemokine (C-X-C motif) receptor 2 (CXCR2)-dependent recruitment of neutrophils into the airways. Deletion of Toll-like receptor 4 (TLR4) abolishes CXCL chemokine secretion and neutrophil recruitment induced by a single RWPE challenge and inhibits induction of allergic sensitization and airway inflammation after repeated exposures to RWPE. Forced induction of CXCL chemokine secretion and neutrophil recruitment in mice lacking TLR4 also reconstitutes the ability of multiple challenges of RWPE to induce allergic airway inflammation. Blocking RWPE-induced neutrophil recruitment in wild-type mice by administration of a CXCR2 inhibitor inhibits the ability of repeated exposures to RWPE to stimulate allergic sensitization and airway inflammation. Administration of neutrophils derived from naive donor mice into the airways of Tlr4 knockout recipient mice after each repeated RWPE challenge reconstitutes allergic sensitization and inflammation in these mice. Together these observations indicate that pollen-induced recruitment of neutrophils is TLR4 and CXCR2 dependent and that recruitment of neutrophils is a critical rate-limiting event that stimulates induction of allergic sensitization and airway inflammation. Inhibiting pollen-induced recruitment of neutrophils, such as by administration of CXCR2 antagonists, may be a novel strategy to prevent initiation of pollen-induced allergic airway inflammation. PMID:26086549

Facilitation of Allergic Sensitization and Allergic Airway Inflammation by Pollen-Induced Innate Neutrophil Recruitment.

PubMed

Hosoki, Koa; Aguilera-Aguirre, Leopoldo; Brasier, Allan R; Kurosky, Alexander; Boldogh, Istvan; Sur, Sanjiv

2016-01-01

Neutrophil recruitment is a hallmark of rapid innate immune responses. Exposure of airways of naive mice to pollens rapidly induces neutrophil recruitment. The innate mechanisms that regulate pollen-induced neutrophil recruitment and the contribution of this neutrophilic response to subsequent induction of allergic sensitization and inflammation need to be elucidated. Here we show that ragweed pollen extract (RWPE) challenge in naive mice induces C-X-C motif ligand (CXCL) chemokine synthesis, which stimulates chemokine (C-X-C motif) receptor 2 (CXCR2)-dependent recruitment of neutrophils into the airways. Deletion of Toll-like receptor 4 (TLR4) abolishes CXCL chemokine secretion and neutrophil recruitment induced by a single RWPE challenge and inhibits induction of allergic sensitization and airway inflammation after repeated exposures to RWPE. Forced induction of CXCL chemokine secretion and neutrophil recruitment in mice lacking TLR4 also reconstitutes the ability of multiple challenges of RWPE to induce allergic airway inflammation. Blocking RWPE-induced neutrophil recruitment in wild-type mice by administration of a CXCR2 inhibitor inhibits the ability of repeated exposures to RWPE to stimulate allergic sensitization and airway inflammation. Administration of neutrophils derived from naive donor mice into the airways of Tlr4 knockout recipient mice after each repeated RWPE challenge reconstitutes allergic sensitization and inflammation in these mice. Together these observations indicate that pollen-induced recruitment of neutrophils is TLR4 and CXCR2 dependent and that recruitment of neutrophils is a critical rate-limiting event that stimulates induction of allergic sensitization and airway inflammation. Inhibiting pollen-induced recruitment of neutrophils, such as by administration of CXCR2 antagonists, may be a novel strategy to prevent initiation of pollen-induced allergic airway inflammation.

Low-Cost and Rapid Fabrication of Metallic Nanostructures for Sensitive Biosensors Using Hot-Embossing and Dielectric-Heating Nanoimprint Methods.

PubMed

Lee, Kuang-Li; Wu, Tsung-Yeh; Hsu, Hsuan-Yeh; Yang, Sen-Yeu; Wei, Pei-Kuen

2017-07-02

We propose two approaches-hot-embossing and dielectric-heating nanoimprinting methods-for low-cost and rapid fabrication of periodic nanostructures. Each nanofabrication process for the imprinted plastic nanostructures is completed within several seconds without the use of release agents and epoxy. Low-cost, large-area, and highly sensitive aluminum nanostructures on A4 size plastic films are fabricated by evaporating aluminum film on hot-embossing nanostructures. The narrowest bandwidth of the Fano resonance is only 2.7 nm in the visible light region. The periodic aluminum nanostructure achieves a figure of merit of 150, and an intensity sensitivity of 29,345%/RIU (refractive index unit). The rapid fabrication is also achieved by using radio-frequency (RF) sensitive plastic films and a commercial RF welding machine. The dielectric-heating, using RF power, takes advantage of the rapid heating/cooling process and lower electric power consumption. The fabricated capped aluminum nanoslit array has a 5 nm Fano linewidth and 490.46 nm/RIU wavelength sensitivity. The biosensing capabilities of the metallic nanostructures are further verified by measuring antigen-antibody interactions using bovine serum albumin (BSA) and anti-BSA. These rapid and high-throughput fabrication methods can benefit low-cost, highly sensitive biosensors and other sensing applications.

Low-Cost and Rapid Fabrication of Metallic Nanostructures for Sensitive Biosensors Using Hot-Embossing and Dielectric-Heating Nanoimprint Methods

PubMed Central

Lee, Kuang-Li; Wu, Tsung-Yeh; Hsu, Hsuan-Yeh; Yang, Sen-Yeu; Wei, Pei-Kuen

2017-01-01

We propose two approaches—hot-embossing and dielectric-heating nanoimprinting methods—for low-cost and rapid fabrication of periodic nanostructures. Each nanofabrication process for the imprinted plastic nanostructures is completed within several seconds without the use of release agents and epoxy. Low-cost, large-area, and highly sensitive aluminum nanostructures on A4 size plastic films are fabricated by evaporating aluminum film on hot-embossing nanostructures. The narrowest bandwidth of the Fano resonance is only 2.7 nm in the visible light region. The periodic aluminum nanostructure achieves a figure of merit of 150, and an intensity sensitivity of 29,345%/RIU (refractive index unit). The rapid fabrication is also achieved by using radio-frequency (RF) sensitive plastic films and a commercial RF welding machine. The dielectric-heating, using RF power, takes advantage of the rapid heating/cooling process and lower electric power consumption. The fabricated capped aluminum nanoslit array has a 5 nm Fano linewidth and 490.46 nm/RIU wavelength sensitivity. The biosensing capabilities of the metallic nanostructures are further verified by measuring antigen–antibody interactions using bovine serum albumin (BSA) and anti-BSA. These rapid and high-throughput fabrication methods can benefit low-cost, highly sensitive biosensors and other sensing applications. PMID:28671600

Diagnostic performance of the "MESACUP anti-Skin profile TEST".

PubMed

Horváth, Orsolya N; Varga, Rita; Kaneda, Makoto; Schmidt, Enno; Ruzicka, Thomas; Sárdy, Miklós

2016-01-01

The "MESACUP anti-Skin profile TEST" is a new, commercially available ELISA kit to detect circulating IgG autoantibodies against desmoglein 1, desmoglein 3, BP180, BP230, and type VII collagen, both simultaneously and more rapidly than previous assays. The aim of this study was to evaluate the diagnostic accuracy of this kit for the diagnosis of pemphigus foliaceus, pemphigus vulgaris, bullous pemphigoid and epidermolysis bullosa acquisita. Dual-centre retrospective study in which 138 patients with autoimmune blistering diseases were compared to 40 controls Using the MESACUP anti-Skin profile TEST, both sensitivities and specificities for desmoglein 1, desmoglein 3, BP180, BP230, and type VII collagen autoantibodies were similar to those obtained using previous, specific ELISA systems and 88% of the results were concordant without any significant difference. The MESACUP anti-Skin profile TEST had a similar performance to previously produced ELISA systems. The novel kit can be used for rapid diagnosis of most common autoimmune blistering diseases and is especially suitable for identifying overlapping disorders.

Nano-volume drop patterning for rapid on-chip neuronal connect-ability assays.

PubMed

Petrelli, Alessia; Marconi, Emanuele; Salerno, Marco; De Pietri Tonelli, Davide; Berdondini, Luca; Dante, Silvia

2013-11-21

The ability of neurons to extend projections and to form physical connections among them (i.e., "connect-ability") is altered in several neuropathologies. The quantification of these alterations is an important read-out to investigate pathogenic mechanisms and for research and development of neuropharmacological therapies, however current morphological analysis methods are very time-intensive. Here, we present and characterize a novel on-chip approach that we propose as a rapid assay. Our approach is based on the definition on a neuronal cell culture substrate of discrete patterns of adhesion protein spots (poly-d-lysine, 23 ± 5 μm in diameter) characterized by controlled inter-spot separations of increasing distance (from 40 μm to 100 μm), locally adsorbed in an adhesion-repulsive agarose layer. Under these conditions, the connect-ability of wild type primary neurons from rodents is shown to be strictly dependent on the inter-spot distance, and can be rapidly documented by simple optical read-outs. Moreover, we applied our approach to identify connect-ability defects in neurons from a mouse model of 22q11.2 deletion syndrome/DiGeorge syndrome, by comparative trials with wild type preparations. The presented results demonstrate the sensitivity and reliability of this novel on-chip-based connect-ability approach and validate the use of this method for the rapid assessment of neuronal connect-ability defects in neuropathologies.

Development of a highly sensitive immunochromatographic detection kit for H5 influenza virus hemagglutinin using silver amplification.

PubMed

Wada, Atsuhiko; Sakoda, Yoshihiro; Oyamada, Takayoshi; Kida, Hiroshi

2011-12-01

H5N1, a highly pathogenic avian influenza virus (HPAIV), has become a serious epizootic threat to the poultry population in Asia. In addition, significant numbers of human cases of HPAIV infection have been reported to date. To prevent the spread of HPAIV among humans and to allow for timely medical intervention, a rapid and high sensitive method is needed to detect and subtype the causative HPAIVs. In the present study, a silver amplification technique used in photographic development was combined with immunochromatography technologies and a highly sensitive and rapid diagnostic test to detect the hemagglutinin of H5 influenza viruses was developed. The sensitivity of the test kit was increased 500 times by silver amplification. The sensitivity of the method was more than 10 times higher than those of conventional rapid influenza diagnostic tests, which detect viral nucleoproteins. The diagnostic system developed in the present study can therefore provide rapid and highly sensitive results and will be useful for diagnosis of H5 HPAIV infection in humans and animals. Copyright © 2011 Elsevier B.V. All rights reserved.

Direct biosensor detection of botulinum neurotoxin endopeptidase activity in sera from patients with type A botulism.

PubMed

Lévêque, Christian; Ferracci, Géraldine; Maulet, Yves; Mazuet, Christelle; Popoff, Michel; Seagar, Michael; El Far, Oussama

2014-07-15

Botulinum neurotoxin A (BoNT/A) has intrinsic endoprotease activity specific for SNAP-25, a key protein for presynaptic neurotransmitter release. The inactivation of SNAP-25 by BoNT/A underlies botulism, a rare but potentially fatal disease. There is a crucial need for a rapid and sensitive in vitro serological test for BoNT/A to replace the current in vivo mouse bioassay. Cleavage of SNAP-25 by BoNT/A generates neo-epitopes which can be detected by binding of a monoclonal antibody (mAb10F12) and thus measured by surface plasmon resonance (SPR). We have explored two SPR assay formats, with either mAb10F12 or His6-SNAP-25 coupled to the biosensor chip. When BoNT/A was incubated with SNAP-25 in solution and the reaction products were captured on a mAb-coated chip, a sensitivity of 5 fM (0.1LD50/ml serum) was obtained. However, this configuration required prior immunoprecipitation of BoNT/A. A sensitivity of 0.5 fM in 10% serum (0.1 LD50/ml serum) was attained when SNAP-25 was coupled directly to the chip, followed by sequential injection of BoNT/A samples and mAb10F12 into the flow system to achieve on-chip cleavage and detection, respectively. This latter format detected BoNT/A endoprotease activity in 50-100 µl serum samples from all patients (11/11) with type A botulism within 5h. No false positives occurred in sera from healthy subjects or patients with other neurological diseases. The automated chip-based procedure has excellent specificity and sensitivity, with significant advantages over the mouse bioassay in terms of rapidity, required sample volume and animal ethics. Copyright © 2014 Elsevier B.V. All rights reserved.

Functional assessment of sodium chloride cotransporter NCC mutants in polarized mammalian epithelial cells.

PubMed

Rosenbaek, Lena L; Rizzo, Federica; MacAulay, Nanna; Staub, Olivier; Fenton, Robert A

2017-08-01

The thiazide-sensitive sodium chloride cotransporter NCC is important for maintaining serum sodium (Na + ) and, indirectly, serum potassium (K + ) levels. Functional studies on NCC have used cell lines with native NCC expression, transiently transfected nonpolarized cell lines, or Xenopus laevis oocytes. Here, we developed the use of polarized Madin-Darby canine kidney type I (MDCKI) mammalian epithelial cell lines with tetracycline-inducible human NCC expression to study NCC activity and membrane abundance in the same system. In radiotracer assays, induced cells grown on filters had robust thiazide-sensitive and chloride dependent sodium-22 ( 22 Na) uptake from the apical side. To minimize cost and maximize throughput, assays were modified to use cells grown on plastic. On plastic, cells had similar thiazide-sensitive 22 Na uptakes that increased following preincubation of cells in chloride-free solutions. NCC was detected in the plasma membrane, and both membrane abundance and phosphorylation of NCC were increased by incubation in chloride-free solutions. Furthermore, in cells exposed for 15 min to low or high extracellular K + , the levels of phosphorylated NCC increased and decreased, respectively. To demonstrate that the system allows rapid and systematic assessment of mutated NCC, three phosphorylation sites in NCC were mutated, and NCC activity was examined. 22 Na fluxes in phosphorylation-deficient mutants were reduced to baseline levels, whereas phosphorylation-mimicking mutants were constitutively active, even without chloride-free stimulation. In conclusion, this system allows the activity, cellular localization, and abundance of wild-type or mutant NCC to be examined in the same polarized mammalian expression system in a rapid, easy, and low-cost fashion. Copyright © 2017 the American Physiological Society.

NT-ProBNP and Troponin T and Risk of Rapid Kidney Function Decline and Incident CKD in Elderly Adults

PubMed Central

Katz, Ronit; Dalrymple, Lorien; de Boer, Ian; DeFilippi, Christopher; Kestenbaum, Bryan; Park, Meyeon; Sarnak, Mark; Seliger, Stephen; Shlipak, Michael

2015-01-01

Background and objectives Elevations in N-terminal pro–B-type natriuretic peptide and high-sensitivity troponin T are associated with poor cardiovascular outcomes. Whether elevations in these cardiac biomarkers are associated with decline in kidney function was evaluated. Design, setting, participants, & measurements N-terminal pro–B-type natriuretic peptide and troponin T were measured at baseline in 3752 participants free of heart failure in the Cardiovascular Health Study. eGFR was determined from the Chronic Kidney Disease Epidemiology Collaboration equation using serum cystatin C. Rapid decline in kidney function was defined as decline in serum cystatin C eGFR≥30%, and incident CKD was defined as the onset of serum cystatin C eGFR<60 among those without CKD at baseline (n=2786). Cox regression models were used to examine the associations of each biomarker with kidney function decline adjusting for demographics, baseline serum cystatin C eGFR, diabetes, and other CKD risk factors. Results In total, 503 participants had rapid decline in serum cystatin C eGFR over a mean follow-up time of 6.41 (1.81) years, and 685 participants developed incident CKD over a mean follow-up time of 6.41 (1.74) years. Participants in the highest quartile of N-terminal pro–B-type natriuretic peptide (>237 pg/ml) had an 67% higher risk of rapid decline and 38% higher adjusted risk of incident CKD compared with participants in the lowest quartile (adjusted hazard ratio for serum cystatin C eGFR rapid decline, 1.67; 95% confidence interval, 1.25 to 2.23; hazard ratio for incident CKD, 1.38; 95% confidence interval, 1.08 to 1.76). Participants in the highest category of troponin T (>10.58 pg/ml) had 80% greater risk of rapid decline compared with participants in the lowest category (adjusted hazard ratio, 1.80; 95% confidence interval, 1.35 to 2.40). The association of troponin T with incident CKD was not statistically significant (hazard ratio, 1.17; 95% confidence interval, 0.92 to 1.50). Conclusions Elevated N-terminal pro–B-type natriuretic peptide and troponin T are associated with rapid decline of kidney function and incident CKD. Additional studies are needed to evaluate the mechanisms that may explain this association. PMID:25605700

On-bead combinatorial synthesis and imaging of chemical exchange saturation transfer magnetic resonance imaging agents to identify factors that influence water exchange.

PubMed

Napolitano, Roberta; Soesbe, Todd C; De León-Rodríguez, Luis M; Sherry, A Dean; Udugamasooriya, D Gomika

2011-08-24

The sensitivity of magnetic resonance imaging (MRI) contrast agents is highly dependent on the rate of water exchange between the inner sphere of a paramagnetic ion and bulk water. Normally, identifying a paramagnetic complex that has optimal water exchange kinetics is done by synthesizing and testing one compound at a time. We report here a rapid, economical on-bead combinatorial synthesis of a library of imaging agents. Eighty different 1,4,7,10-tetraazacyclododecan-1,4,7,10-tetraacetic acid (DOTA)-tetraamide peptoid derivatives were prepared on beads using a variety of charged, uncharged but polar, hydrophobic, and variably sized primary amines. A single chemical exchange saturation transfer image of the on-bead library easily distinguished those compounds having the most favorable water exchange kinetics. This combinatorial approach will allow rapid screening of libraries of imaging agents to identify the chemical characteristics of a ligand that yield the most sensitive imaging agents. This technique could be automated and readily adapted to other types of MRI or magnetic resonance/positron emission tomography agents as well.

Nanometal particle reagents for sensitive, MEMS based fiber-optic, multi-analyte, immuno-biosensing

NASA Astrophysics Data System (ADS)

Hong, Bin

Integration of nanotechnology to medical diagnostics has brought a new era to public health practice. An excellent example is the utilization of unique optoelectronic properties of nanoparticles to develop highly sensitive biosensing devices for point-of-care (POC) disease diagnosis/prognosis. Fluorophore mediated, immuno-biosensors are important disease detection tools. The property of intra-molecular fluorescence quenching of most fluorophores, however, limits the sensitivity of this type of sensors. A plasmon-rich nanometal particle (NMP) can transfer the lone pair electrons of a fluorophore, which normally participate in the fluorescence self-quenching, to its surface plasmon field, resulting in artificial fluorescence enhancement. The enhancement was found to depend on the metal type, the particle size, the distance between a particle and a fluorophore, and the quantum yield of a fluorophore. Some biocompatible solvents were also found to increase the fluorescence emission efficiency via effective dipole coupling between the fluorophore and the solvent molecule. The application of solvents in inmuno-sensing could additionally improve the fluorescence light retrieval by the conformational change of the protein complexes in solvent. The mixture of the NMP and the solvent, which we defined as nanometal particle reagent (NMPR), provided even higher enhancements. Cardiovascular diseases (CVDs) kill 1 person in every 6 seconds. Among the CVDs, acute myocardial infarction (AMI; commonly known as heart attack) is the most dangerous and time-sensitive killer. A rapid and accurate AMI diagnosis is crucial for saving many lives. For this purpose, a fluorophore mediated, immuno-reaction based, multi-cardiac-marker sensing device was developed, to quantify four myocardium-specific proteins simultaneously, accurately, rapidly, and user-friendly. The four cardiac markers of our choice were myoglobin (MG), C-reactive protein (CRP), cardiac troponin I (cTnI), and B-type natriuretic peptide (BNP). Two of these cardiac markers, cTnI and BNP, were rather difficult to sense due to their low concentrations (tens of picomolar) in blood plasma immediately after the AMI. The NMPRs that we have developed enhanced the sensor signals as high as 8 times, accomplishing a sensitive and accurate quantification of all four markers in 7 minutes with an average signal-to-noise ratio of 35. As a promising POC sensing device, system portability, sensing reliability, and user-friendly operation are important. Micro-electro-mechanical system (MEMS) technology was, therefore, integrated to the immuno-sensing device with microfluidic control and microfabrication. A LabVIEW(TM) computer code was also written for a "one-click" automated immunoassay and a real-time data analysis. Our four-cardiac-marker immuno-sensing device incorporated with nanotechnology and MEMS technology is capable of simultaneous quantification at a near-real time, which can save many lives. This device can be also used for measuring any disease-representing biomarkers (e.g., cancer markers) for rapid and accurate disease diagnosis/prognosis.

Ultrasensitive interdigitated capacitance immunosensor using gold nanoparticles.

PubMed

Alizadeh Zeinabad, Hojjat; Ghourchian, Hedayatollah; Falahati, Mojtaba; Fathipour, Morteza; Azizi, Marzieh; Boutorabi, Seyed Mehdi

2018-06-29

Immunosensors based on interdigitated electrodes (IDEs), have recently demonstrated significant improvements in the sensitivity of capacitance detection. Herein, a novel type of highly sensitive, compact and portable immunosensor based on a gold interdigital capacitor has been designed and developed for the rapid detection of hepatitis B surface antigen (HBsAg). To improve the efficiency of antibody immobilization and time-saving, a self-assembled monolayer (SAM) of 2-mercaptoethylamine film was coated on IDEs. Afterwards, carboxyl groups on primary antibodies were activated through 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide and were immobilized on amino-terminated SAM for better control of the oriented immobilization of antibodies on gold IDEs. In addition, gold nanoparticles conjugated with a secondary antibody were used to enhance the sensitivity. Under optimal conditions, the immunosensor exhibited the sensitivity of 0.22 nF.pg ml -1 , the linear range from 5 pg ml -1 to 1 ng ml -1 and the detection limit of 1.34 pg ml -1 , at a signal-to-noise ratio of 3.

Ultrasensitive interdigitated capacitance immunosensor using gold nanoparticles

NASA Astrophysics Data System (ADS)

Alizadeh Zeinabad, Hojjat; Ghourchian, Hedayatollah; Falahati, Mojtaba; Fathipour, Morteza; Azizi, Marzieh; Boutorabi, Seyed Mehdi

2018-06-01

Immunosensors based on interdigitated electrodes (IDEs), have recently demonstrated significant improvements in the sensitivity of capacitance detection. Herein, a novel type of highly sensitive, compact and portable immunosensor based on a gold interdigital capacitor has been designed and developed for the rapid detection of hepatitis B surface antigen (HBsAg). To improve the efficiency of antibody immobilization and time-saving, a self-assembled monolayer (SAM) of 2-mercaptoethylamine film was coated on IDEs. Afterwards, carboxyl groups on primary antibodies were activated through 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide and were immobilized on amino-terminated SAM for better control of the oriented immobilization of antibodies on gold IDEs. In addition, gold nanoparticles conjugated with a secondary antibody were used to enhance the sensitivity. Under optimal conditions, the immunosensor exhibited the sensitivity of 0.22 nF.pg ml–1, the linear range from 5 pg ml‑1 to 1 ng ml–1 and the detection limit of 1.34 pg ml‑1, at a signal-to-noise ratio of 3.

Rapid Detection of Urinary Tract Infections via Bacterial Nuclease Activity.

PubMed

Flenker, Katie S; Burghardt, Elliot L; Dutta, Nirmal; Burns, William J; Grover, Julia M; Kenkel, Elizabeth J; Weaver, Tyler M; Mills, James; Kim, Hyeon; Huang, Lingyan; Owczarzy, Richard; Musselman, Catherine A; Behlke, Mark A; Ford, Bradley; McNamara, James O

2017-06-07

Rapid and accurate bacterial detection methods are needed for clinical diagnostic, water, and food testing applications. The wide diversity of bacterial nucleases provides a rich source of enzymes that could be exploited as signal amplifying biomarkers to enable rapid, selective detection of bacterial species. With the exception of the use of micrococcal nuclease activity to detect Staphylococcus aureus, rapid methods that detect bacterial pathogens via their nuclease activities have not been developed. Here, we identify endonuclease I as a robust biomarker for E. coli and develop a rapid ultrasensitive assay that detects its activity. Comparison of nuclease activities of wild-type and nuclease-knockout E. coli clones revealed that endonuclease I is the predominant DNase in E. coli lysates. Endonuclease I is detectable by immunoblot and activity assays in uropathogenic E. coli strains. A rapid assay that detects endonuclease I activity in patient urine with an oligonucleotide probe exhibited substantially higher sensitivity for urinary tract infections than that reported for rapid urinalysis methods. The 3 hr turnaround time is much shorter than that of culture-based methods, thereby providing a means for expedited administration of appropriate antimicrobial therapy. We suggest this approach could address various unmet needs for rapid detection of E. coli. Copyright © 2017 The American Society of Gene and Cell Therapy. Published by Elsevier Inc. All rights reserved.

Development and Comparison of a Rapid Isothermal Nucleic Acid Amplification Test for Typing of Herpes Simplex Virus Types 1 and 2 on a Portable Fluorescence Detector

PubMed Central

Tong, Yanhong; McCarthy, Kaitlin; Kong, Huimin; Lemieux, Bertrand

2013-01-01

We have developed a rapid and simple molecular test, the IsoGlow HSV Typing assay, for the detection and typing of herpes simplex virus (type 1 and 2) from genital or oral lesions. Clinical samples suspended in viral transport mediums are simply diluted and then added to a helicase-dependent amplification master mix. The amplification and detection were performed on a portable fluorescence detector called the FireFly instrument. Detection of amplification products is based on end-point analysis using cycling probe technology. An internal control nucleic acid was included in the amplification master mix to monitor the presence of amplification inhibitors in the samples. Because the device has only two fluorescence detection channels, two strategies were developed and compared to detect the internal control template: internal control detected by melting curve analysis using a dual-labeled probe, versus internal control detection using end-point fluorescence release by a CPT probe at a lower temperature. Both have a total turnaround time of about 1 hour. Clinical performance relative to herpes viral culture was evaluated using 176 clinical specimens. Both formats of the IsoGlow HSV typing assay had sensitivities comparable to that of the Food and Drug Administration–cleared IsoAmp HSV (BioHelix Corp., Beverly MA) test and specificity for the two types of HSV comparable to that of ELVIS HSV (Diagnostic Hybrids, Athens, OH). PMID:22951487

Establishment of new transmissible and drug-sensitive human immunodeficiency virus type 1 wild types due to transmission of nucleoside analogue-resistant virus.

PubMed

de Ronde, A; van Dooren, M; van Der Hoek, L; Bouwhuis, D; de Rooij, E; van Gemen, B; de Boer, R; Goudsmit, J

2001-01-01

Sequence analysis of human immunodeficiency virus type 1 (HIV-1) from 74 persons with acute infections identified eight strains with mutations in the reverse transcriptase (RT) gene at positions 41, 67, 68, 70, 215, and 219 associated with resistance to the nucleoside analogue zidovudine (AZT). Follow-up of the fate of these resistant HIV-1 strains in four newly infected individuals revealed that they were readily replaced by sensitive strains. The RT of the resistant viruses changed at amino acid 215 from tyrosine (Y) to aspartic acid (D) or serine (S), with asparagine (N) as a transient intermediate, indicating the establishment of new wild types. When we introduced these mutations and the original threonine (T)-containing wild type into infectious molecular clones and assessed their competitive advantage in vitro, the order of fitness was in accord with the in vivo observations: 215Y < 215D = 215S = 215T. As detected by real-time nucleic acid sequence-based amplification with two molecular beacons, the addition of AZT or stavudine (d4T) to the viral cultures favored the 215Y mutant in a dose-dependent manner. Our results illustrate that infection with nucleoside analogue-resistant HIV leads in newly infected individuals to mutants that are sensitive to nucleoside analogues, but only a single mutation removed from drug-resistant HIV. Such mutants were shown to be transmissible, stable, and prone to rapid selection for resistance to AZT or d4T as soon as antiretroviral therapy was administered. Monitoring of patients for the presence of new HIV-1 wild types with D, S, or N residues at position 215 may be warranted in order to estimate the threat to long-term efficacy of regimens including nucleoside analogues.

Temperature shock, injury and transient sensitivity to nisin in Gram negatives.

PubMed

Boziaris, I S; Adams, M R

2001-10-01

The effect of thermal stresses on survival, injury and nisin sensitivity was investigated in Salmonella Enteritidis PT4, PT7 and Pseudomonas aeruginosa. Heating at 55 degrees C, rapid chilling to 0.5 degrees C or freezing at -20 degrees C produced transient sensitivity to nisin. Cells were only sensitive if nisin was present during stress. Resistance recovered rapidly afterwards, though some cells displayed residual injury. Injury was assessed by SDS sensitivity, hydrophobicity changes, lipopolysaccharide release and NPN uptake. LPS release and hydrophobicity were not always associated with transient nisin sensitivity. Uptake of NPN correlated better but persisted longer after treatment. Thermal shocks produce transient injury to the outer membrane, allowing nisin access. After treatment, the permeability barrier is rapidly restored by a process apparently involving reorganization rather than biosynthetic repair. Inclusion of nisin during food treatments that impose sub-lethal stress on Gram negatives could increase process lethality, enhancing microbiological safety and stability.

Highly Sensitive, Label-Free Detection of 2,4-Dichlorophenoxyacetic Acid Using an Optofluidic Chip.

PubMed

Feng, Xueling; Zhang, Gong; Chin, Lip Ket; Liu, Ai Qun; Liedberg, Bo

2017-07-28

A highly sensitive approach for rapid and label-free detection of the herbicide 2,4-dichlorophenoxyacetic acid (2,4-D) using an optofluidic chip is demonstrated. The optofluidic chip is prepared by covalent immobilization of 2,4-D-bovine serum albumin (2,4-D-BSA) conjugate to an integrated microring resonator. Subsequent detection of 2,4-D carried out in a competitive immunoreaction format enables selective detection of 2,4-D in different types of water samples, including bottled, tap, and lake water, at a limit of detection (LOD) of 4.5 pg/mL and in a quantitative range of 15-10 5 pg/mL. The microring resonator-based optofluidic chip is reusable with ultrahigh sensitivity that offers real-time and on-site detection of low-molecular-weight targets for potential applications in food safety and environmental monitoring.

The coeruleus/subcoeruleus complex in idiopathic rapid eye movement sleep behaviour disorder.

PubMed

Ehrminger, Mickael; Latimier, Alice; Pyatigorskaya, Nadya; Garcia-Lorenzo, Daniel; Leu-Semenescu, Smaranda; Vidailhet, Marie; Lehericy, Stéphane; Arnulf, Isabelle

2016-04-01

Idiopathic rapid eye movement sleep behaviour disorder is characterized by nocturnal violence, increased muscle tone during rapid eye movement sleep and the lack of any other neurological disease. However, idiopathic rapid eye movement sleep behaviour disorder can precede parkinsonism and dementia by several years. Using 3 T magnetic resonance imaging and neuromelanin-sensitive sequences, we previously found that the signal intensity was reduced in the locus coeruleus/subcoeruleus area of patients with Parkinson's disease and rapid eye movement sleep behaviour disorder. Here, we studied the integrity of the locus coeruleus/subcoeruleus complex with neuromelanin-sensitive imaging in 21 patients with idiopathic rapid eye movement sleep behaviour disorder and compared the results with those from 21 age- and gender-matched healthy volunteers. All subjects underwent a clinical examination, motor, cognitive, autonomous, psychological, olfactory and colour vision tests, and rapid eye movement sleep characterization using video-polysomnography and 3 T magnetic resonance imaging. The patients more frequently had preclinical markers of alpha-synucleinopathies, including constipation, olfactory deficits, orthostatic hypotension, and subtle motor impairment. Using neuromelanin-sensitive imaging, reduced signal intensity was identified in the locus coeruleus/subcoeruleus complex of the patients with idiopathic rapid eye movement sleep behaviour. The mean sensitivity of the visual analyses of the signal performed by neuroradiologists who were blind to the clinical diagnoses was 82.5%, and the specificity was 81% for the identification of idiopathic rapid eye movement sleep behaviour. The results confirm that this complex is affected in idiopathic rapid eye movement sleep behaviour (to the same degree as it is affected in Parkinson's disease). Neuromelanin-sensitive imaging provides an early marker of non-dopaminergic alpha-synucleinopathy that can be detected on an individual basis. © The Author (2016). Published by Oxford University Press on behalf of the Guarantors of Brain. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

EU-approved rapid tests might underestimate bovine spongiform encephalopathy infection in goats.

PubMed

Meloni, Daniela; Bozzetta, Elena; Langeveld, Jan P M; Groschup, Martin H; Goldmann, Wilfred; Andrèoletti, Olivier; Lantier, Isabelle; Van Keulen, Lucien; Bossers, Alex; Pitardi, Danilo; Nonno, Romolo; Sklaviadis, Theodoros; Ingravalle, Francesco; Peletto, Simone; Colussi, Silvia; Acutis, Pier Luigi

2017-03-01

We report the diagnostic sensitivity of 3 EU-approved rapid tests (ELISAs; 1 from IDEXX and 2 from Bio-Rad) for the detection of transmissible spongiform encephalopathy diseases in goats. Ninety-eight goat brainstem samples were tested. All the rapid tests had 100% specificity and ≥80% sensitivity, with the IDEXX test significantly more sensitive than the 2 Bio-Rad tests. All tests detected 100% of samples from goats with clinical scrapie, but missed 8% (IDEXX) to 33% (Bio-Rad SG) of samples from preclinical goats. Importantly, only IDEXX picked up all samples from clinical bovine spongiform encephalopathy (BSE)-infected goats, whereas the other 2 rapid tests missed 15% (Bio-Rad SG) to 25% (Bio-Rad SAP). These results show that a fraction of preclinical scrapie infections are likely missed by EU surveillance, with sensitivity of detection strongly dependent on the choice of the rapid test. Moreover, a significant proportion of clinical BSE infections are underestimated by using either Bio-Rad test. Assuming that the same sensitivity on preclinical goats would also occur in BSE-infected goats, our data suggest that IDEXX is likely the most sensitive test for detecting preclinical field cases of BSE infection in goats, although with an 8% failure rate. These results raise some concerns about the reliability of current EU surveillance figures on BSE infection in goats.

The sensitivity and the specifity of rapid antigen test in streptococcal upper respiratory tract infections.

PubMed

Gurol, Yesim; Akan, Hulya; Izbirak, Guldal; Tekkanat, Zuhal Tazegun; Gunduz, Tehlile Silem; Hayran, Osman; Yilmaz, Gulden

2010-06-01

It is aimed to detect the sensitivity and specificity of rapid antigen detection of group A beta hemolytic streptococci from throat specimen compared with throat culture. The other goal of the study is to help in giving clinical decisions in upper respiratory tract infections according to the age group, by detection of sensitivity and positive predictive values of the rapid tests and throat cultures. Rapid antigen detection and throat culture results for group A beta hemolytic streptococci from outpatients attending to our university hospital between the first of November 2005 and 31st of December 2008 were evaluated retrospectively. Throat samples were obtained by swabs from the throat and transported in the Stuart medium and Quickvue Strep A [Quidel, San Diego, USA] cassette test was applied and for culture, specimen was inoculated on 5% blood sheep agar and identified according to bacitracin and trimethoprim-sulphametaxazole susceptibility from beta hemolytic colonies. During the dates between the first of November 2005 and 31st of December 2008, from 453 patients both rapid antigen detection and throat culture were evaluated. Rapid antigen detection sensitivity and specificity were found to be 64.6% and 96.79%, respectively. The positive predictive value was 80.95% whereas negative predictive value was 92.82%. Kappa index was 0.91. When the results were evaluated according to the age groups, the sensitivity and the positive predictive value of rapid antigen detection in children were 70%, 90.3% and in adults 59.4%, 70.4%. When bacterial infection is concerned to prevent unnecessary antibiotic use, rapid streptococcal antigen test (RSAT) is a reliable method to begin immediate treatment. To get the maximum sensitivity of RSAT, the specimen collection technique used and education of the health care workers is important. While giving clinical decision, it must be taken into consideration that the sensitivity and the positive predictive value of the RSAT is quite lower in adult age group than in pediatric age group. Copyright (c) 2010 Elsevier Ireland Ltd. All rights reserved.

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

Horesh, Assaf; Kulkarni, Shrinivas R.; Corsi, Alessandra

Only a few cases of Type Ic supernovae (SNe) with high-velocity ejecta (≥0.2 c) have been discovered and studied. Here, we present our analysis of radio and X-ray observations of the Type Ic SN PTF 12gzk. The radio emission declined less than 10 days after explosion, suggesting SN ejecta expanding at high velocity (∼0.3 c). The radio data also indicate that the density of the circumstellar material (CSM) around the supernova is lower by a factor of ∼10 than the CSM around normal Type Ic SNe. PTF 12gzk may therefore be an intermediate event between a 'normal' SN Ic andmore » a gamma-ray-burst-SN-like event. Our observations of this rapidly declining radio SN at a distance of 58 Mpc demonstrates the potential to detect many additional radio SNe, given the new capabilities of the Very Large Array (improved sensitivity and dynamic scheduling), which are currently missed, leading to a biased view of radio SNe Ic. Early optical discovery followed by rapid radio observations would provide a full description of the ejecta velocity distribution and CSM densities around stripped massive star explosions as well as strong clues about the nature of their progenitor stars.« less

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.

Evaluation of the Abbott RealTime MTB and RealTime MTB INH/RIF Assays for Direct Detection of Mycobacterium tuberculosis Complex and Resistance Markers in Respiratory and Extrapulmonary Specimens.

PubMed

Hofmann-Thiel, Sabine; Molodtsov, Nikolay; Antonenka, Uladzimir; Hoffmann, Harald

2016-12-01

The Abbott RealTime MTB (RT MTB) assay is a new automated nucleic acid amplification test for the detection of Mycobacterium tuberculosis complex (MTBC) in clinical specimens. In combination with the RealTime MTB INH/RIF (RT MTB INH/RIF) resistance assay, which can be applied to RT MTB-positive specimens as an add-on assay, the tests also indicate the genetic markers of resistance to isoniazid (INH) and rifampin (RIF). We aimed to evaluate the diagnostic sensitivity and specificity of RT MTB using different types of respiratory and extrapulmonary specimens and to compare performance characteristics directly with those of the FluoroType MTB assay. The resistance results obtained by RT MTB INH/RIF were compared to those from the GenoType MTBDRplus and from phenotypic drug susceptibility testing. A total of 715 clinical specimens were analyzed. Compared to culture, the overall sensitivity of RT MTB was 92.1%; the sensitivity rates for smear-positive and smear-negative samples were 100% and 76.2%, respectively. The sensitivities of smear-negative specimens were almost identical for respiratory (76.3%) and extrapulmonary (76%) specimens. Specificity rates were 100% and 95.8% for culture-negative specimens and those that grew nontuberculous mycobacteria, respectively. RT MTB INH/RIF was applied to 233 RT MTB-positive samples and identified resistance markers in 7.7% of samples. Agreement with phenotypic and genotypic drug susceptibility testing was 99.5%. In conclusion, RT MTB and RT MTB INH/RIF allow for the rapid and accurate diagnosis of tuberculosis (TB) in different types of specimens and reliably indicate resistance markers. The strengths of this system are the comparably high sensitivity with paucibacillary specimens, its ability to detect INH and RIF resistance, and its high-throughput capacities. Copyright © 2016, American Society for Microbiology. All Rights Reserved.

HV1 acts as a sodium sensor and promotes superoxide production in medullary thick ascending limb of Dahl salt-sensitive rats.

PubMed

Jin, Chunhua; Sun, Jingping; Stilphen, Carly A; Smith, Susan M E; Ocasio, Hiram; Bermingham, Brent; Darji, Sandip; Guha, Avirup; Patel, Roshan; Geurts, Aron M; Jacob, Howard J; Lambert, Nevin A; O'Connor, Paul M

2014-09-01

We previously characterized a H(+) transport pathway in medullary thick ascending limb nephron segments that when activated stimulated the production of superoxide by nicotinamide adenine dinucleotide phosphate oxidase. Importantly, the activity of this pathway was greater in Dahl salt-sensitive rats than salt-resistant (SS.13(BN)) rats, and superoxide production was enhanced in low Na(+) media. The goal of this study was to determine the molecular identity of this pathway and its relationship to Na(+). We hypothesized that the voltage-gated proton channel, HV1, was the source of superoxide-stimulating H(+) currents. To test this hypothesis, we developed HV1(-/-) null mutant rats on the Dahl salt-sensitive rat genetic background using zinc-finger nuclease gene targeting. HV1 could be detected in medullary thick limb from wild-type rats. Intracellular acidification using an NH4Cl prepulse in 0 sodium/BaCl2 containing media resulted in superoxide production in thick limb from wild-type but not HV1(-/-) rats (P<0.05) and more rapid recovery of intracellular pH in wild-type rats (ΔpHI 0.005 versus 0.002 U/s, P=0.046, respectively). Superoxide production was enhanced by low intracellular sodium (<10 mmol/L) in both thick limb and peritoneal macrophages only when HV1 was present. When fed a high-salt diet, blood pressure, outer medullary renal injury (tubular casts), and oxidative stress (4-hydroxynonenal staining) were significantly reduced in HV1(-/-) rats compared with wild-type Dahl salt-sensitive rats. We conclude that HV1 is expressed in medullary thick ascending limb and promotes superoxide production in this segment when intracellular Na(+) is low. HV1 contributes to the development of hypertension and renal disease in Dahl salt-sensitive rats. © 2014 American Heart Association, Inc.

Rapid shape detection signals in area V4

PubMed Central

Weiner, Katherine F.; Ghose, Geoffrey M.

2014-01-01

Vision in foveate animals is an active process that requires rapid and constant decision-making. For example, when a new object appears in the visual field, we can quickly decide to inspect it by directing our eyes to the object's location. We studied the contribution of primate area V4 to these types of rapid foveation decisions. Animals performed a reaction time task that required them to report when any shape appeared within a peripherally-located noisy stimulus by making a saccade to the stimulus location. We found that about half of the randomly sampled V4 neurons not only rapidly and precisely represented the appearance of this shape, but they were also predictive of the animal's saccades. A neuron's ability to predict the animal's saccades was not related to the specificity with which the cell represented a single type of shape but rather to its ability to signal whether any shape was present. This relationship between sensory sensitivity and behavioral predictiveness was not due to global effects such as alertness, as it was equally likely to be observed for cells with increases and decreases in firing rate. Careful analysis of the timescales of reliability in these neurons implies that they reflect both feedforward and feedback shape detecting processes. In approximately 7% of our recorded sample, individual neurons were able to predict both the delay and precision of the animal's shape detection performance. This suggests that a subset of V4 neurons may have been directly and causally contributing to task performance and that area V4 likely plays a critical role in guiding rapid, form-based foveation decisions. PMID:25278828

Indirect micro-immunofluorescence test for detecting type-specific antibodies to herpes simplex virus.

PubMed

Forsey, T; Darougar, S

1980-02-01

A rapid indirect micro-immunofluorescence test capable of detecting and differentiating type-specific antibodies to herpes simplex virus is described. The test proved highly sensitive and, in 80 patients with active herpes ocular infection, antibody was detected in 94%. No anti-herpes antibody was detected in a control group of 20 patients with adenovirus infections. Testing of animal sera prepared against herpes simplex virus types 1 and 2 and of human sera from cases of ocular and genital herpes infections showed that the test can differentiate antibodies to the infecting serotypes. Specimens of whole blood, taken by fingerprick, and eye secretions, both collected on cellulose sponges, could be tested by indirect micro-immunofluorescence. Anti-herpes IgG, IgM, and IgA can also be detected.

Comparison of the efficiency control of mycotoxins by some optical immune biosensors

NASA Astrophysics Data System (ADS)

Slyshyk, N. F.; Starodub, N. F.

2013-11-01

It was compared the efficiency of patulin control at the application of such optical biosensors which were based on the surface plasmon resonance (SPR) and nano-porous silicon (sNPS). In last case the intensity of the immune reaction was registered by measuring level of chemiluminescence (ChL) or photocurrent of nPS. The sensitivity of this mycotoxin determination by first type of immune biosensor was 0.05-10 mg/L Approximately the same sensitivity as well as the overall time analysis were demonstrated by the immune biosensor based on the nPS too. Nevertheless, the last type of biosensor was simpler in technical aspect and the cost of analysis was cheapest. That is why, it was recommend the nPS based immune biosensor for wide screening application and SPR one for some additional control or verification of preliminary obtained results. In this article a special attention was given to condition of sample preparation for analysis, in particular, micotoxin extraction from potao and some juices. Moreover, it was compared the efficiency of the above mentioned immune biosensors with such traditional approach of mycotoxin determination as the ELISA-method. In the result of investigation and discussion of obtained data it was concluded that both type of the immune biosensors are able to fulfill modern practice demand in respect sensitivity, rapidity, simplicity and cheapness of analysis.

Pain perception studies in tension-type headache.

PubMed

Bezov, David; Ashina, Sait; Jensen, Rigmor; Bendtsen, Lars

2011-02-01

Tension-type headache (TTH) is a disorder with high prevalence and significant impact on society. Understanding of pathophysiology of TTH is paramount for development of effective treatments and prevention of chronification of TTH. Our aim was to review the findings from pain perception studies of pathophysiology of TTH as well as to review the research of pathophysiology of TTH. Pain perception studies such as measurement of muscle tenderness, pain detection thresholds, pain tolerance thresholds, pain response to suprathreshold stimulation, temporal summation and diffuse noxious inhibitory control (DNIC) have played a central role in elucidating the pathophysiology of TTH. It has been demonstrated that continuous nociceptive input from peripheral myofascial structures may induce central sensitization and thereby chronification of the headache. Measurements of pain tolerance thresholds and suprathreshold stimulation have shown presence of generalized hyperalgesia in chronic tension-type headache (CTTH) patients, while DNIC function has been shown to be reduced in CTTH. One imaging study showed loss of gray matter structures involved in pain processing in CTTH patients. Future studies should aim to integrate pain perception and imaging to confirm this finding. Pharmacological studies have shown that drugs like tricyclic anti-depressant amitriptyline and nitric oxide synthase inhibitors can reverse central sensitization and the chronicity of headache. Finally, low frequency electrical stimulation has been shown to rapidly reverse central sensitization and may be a new modality in treatment of CTTH and other chronic pain disorders. © 2010 American Headache Society.

Combination of methylated-DNA precipitation and methylation-sensitive restriction enzymes (COMPARE-MS) for the rapid, sensitive and quantitative detection of DNA methylation.

PubMed

Yegnasubramanian, Srinivasan; Lin, Xiaohui; Haffner, Michael C; DeMarzo, Angelo M; Nelson, William G

2006-02-09

Hypermethylation of CpG island (CGI) sequences is a nearly universal somatic genome alteration in cancer. Rapid and sensitive detection of DNA hypermethylation would aid in cancer diagnosis and risk stratification. We present a novel technique, called COMPARE-MS, that can rapidly and quantitatively detect CGI hypermethylation with high sensitivity and specificity in hundreds of samples simultaneously. To quantitate CGI hypermethylation, COMPARE-MS uses real-time PCR of DNA that was first digested by methylation-sensitive restriction enzymes and then precipitated by methyl-binding domain polypeptides immobilized on a magnetic solid matrix. We show that COMPARE-MS could detect five genome equivalents of methylated CGIs in a 1000- to 10,000-fold excess of unmethylated DNA. COMPARE-MS was used to rapidly quantitate hypermethylation at multiple CGIs in >155 prostate tissues, including benign and malignant prostate specimens, and prostate cell lines. This analysis showed that GSTP1, MDR1 and PTGS2 CGI hypermethylation as determined by COMPARE-MS could differentiate between malignant and benign prostate with sensitivities >95% and specificities approaching 100%. This novel technology could significantly improve our ability to detect CGI hypermethylation.

Sensitivity of influenza rapid diagnostic tests to H5N1 and 2009 pandemic H1N1 viruses.

PubMed

Sakai-Tagawa, Yuko; Ozawa, Makoto; Tamura, Daisuke; Le, Mai thi Quynh; Nidom, Chairul A; Sugaya, Norio; Kawaoka, Yoshihiro

2010-08-01

Simple and rapid diagnosis of influenza is useful for making treatment decisions in the clinical setting. Although many influenza rapid diagnostic tests (IRDTs) are available for the detection of seasonal influenza virus infections, their sensitivity for other viruses, such as H5N1 viruses and the recently emerged swine origin pandemic (H1N1) 2009 virus, remains largely unknown. Here, we examined the sensitivity of 20 IRDTs to various influenza virus strains, including H5N1 and 2009 pandemic H1N1 viruses. Our results indicate that the detection sensitivity to swine origin H1N1 viruses varies widely among IRDTs, with some tests lacking sufficient sensitivity to detect the early stages of infection when the virus load is low.

Specific and Sensitive Isothermal Electrochemical Biosensor for Plant Pathogen DNA Detection with Colloidal Gold Nanoparticles as Probes

NASA Astrophysics Data System (ADS)

Lau, Han Yih; Wu, Haoqi; Wee, Eugene J. H.; Trau, Matt; Wang, Yuling; Botella, Jose R.

2017-01-01

Developing quick and sensitive molecular diagnostics for plant pathogen detection is challenging. Herein, a nanoparticle based electrochemical biosensor was developed for rapid and sensitive detection of plant pathogen DNA on disposable screen-printed carbon electrodes. This 60 min assay relied on the rapid isothermal amplification of target pathogen DNA sequences by recombinase polymerase amplification (RPA) followed by gold nanoparticle-based electrochemical assessment with differential pulse voltammetry (DPV). Our method was 10,000 times more sensitive than conventional polymerase chain reaction (PCR)/gel electrophoresis and could readily identify P. syringae infected plant samples even before the disease symptoms were visible. On the basis of the speed, sensitivity, simplicity and portability of the approach, we believe the method has potential as a rapid disease management solution for applications in agriculture diagnostics.

Specific and Sensitive Isothermal Electrochemical Biosensor for Plant Pathogen DNA Detection with Colloidal Gold Nanoparticles as Probes.

PubMed

Lau, Han Yih; Wu, Haoqi; Wee, Eugene J H; Trau, Matt; Wang, Yuling; Botella, Jose R

2017-01-17

Developing quick and sensitive molecular diagnostics for plant pathogen detection is challenging. Herein, a nanoparticle based electrochemical biosensor was developed for rapid and sensitive detection of plant pathogen DNA on disposable screen-printed carbon electrodes. This 60 min assay relied on the rapid isothermal amplification of target pathogen DNA sequences by recombinase polymerase amplification (RPA) followed by gold nanoparticle-based electrochemical assessment with differential pulse voltammetry (DPV). Our method was 10,000 times more sensitive than conventional polymerase chain reaction (PCR)/gel electrophoresis and could readily identify P. syringae infected plant samples even before the disease symptoms were visible. On the basis of the speed, sensitivity, simplicity and portability of the approach, we believe the method has potential as a rapid disease management solution for applications in agriculture diagnostics.

Performance of Rapid Influenza Diagnostic Testing in Outbreak Settings

PubMed Central

Winter, Anne-Luise; King, Eddie-Chong; Blair, Joanne; Gubbay, Jonathan B.

2014-01-01

Rapid influenza diagnostic tests (RIDTs) may be useful during institutional respiratory disease outbreaks to identify influenza and enable antivirals to be rapidly administered to patients and for the prophylactic treatment of those exposed to the virus but not yet symptomatic. The performance of RIDTs at the outbreak level is not well documented in the literature. This study aimed to evaluate the performance of RIDTs in comparison with that of real-time reverse transcription (rRT)-PCR in the context of institutional respiratory disease outbreaks. This study included outbreak-related respiratory specimens tested for influenza virus at Public Health Ontario Laboratories by both RIDT and rRT-PCR, from 1 September 2010 to 30 April 2013. At the outbreak level, performance testing of RIDTs compared to rRT-PCR for the detection of any influenza virus type demonstrated an overall sensitivity of 76.5%, a specificity of 99.7%, a positive predictive value (PPV) of 99.5%, and a negative predictive value of 85.3%. Because of their high specificity and PPV, even outside of the influenza season, RIDTs can play a role in screening for influenza virus in outbreaks and instituting antiviral therapy in a timely manner when positive. RIDTs can also be useful in remote settings where molecular virology testing is not easily accessible. Suboptimal sensitivity of RIDTs can be addressed by the use of molecular testing. PMID:25320225

Performance of rapid influenza diagnostic testing in outbreak settings.

PubMed

Peci, Adriana; Winter, Anne-Luise; King, Eddie-Chong; Blair, Joanne; Gubbay, Jonathan B

2014-12-01

Rapid influenza diagnostic tests (RIDTs) may be useful during institutional respiratory disease outbreaks to identify influenza and enable antivirals to be rapidly administered to patients and for the prophylactic treatment of those exposed to the virus but not yet symptomatic. The performance of RIDTs at the outbreak level is not well documented in the literature. This study aimed to evaluate the performance of RIDTs in comparison with that of real-time reverse transcription (rRT)-PCR in the context of institutional respiratory disease outbreaks. This study included outbreak-related respiratory specimens tested for influenza virus at Public Health Ontario Laboratories by both RIDT and rRT-PCR, from 1 September 2010 to 30 April 2013. At the outbreak level, performance testing of RIDTs compared to rRT-PCR for the detection of any influenza virus type demonstrated an overall sensitivity of 76.5%, a specificity of 99.7%, a positive predictive value (PPV) of 99.5%, and a negative predictive value of 85.3%. Because of their high specificity and PPV, even outside of the influenza season, RIDTs can play a role in screening for influenza virus in outbreaks and instituting antiviral therapy in a timely manner when positive. RIDTs can also be useful in remote settings where molecular virology testing is not easily accessible. Suboptimal sensitivity of RIDTs can be addressed by the use of molecular testing. Copyright © 2014, American Society for Microbiology. All Rights Reserved.

Three year evaluation of Xpert MTB/RIF in a low prevalence tuberculosis setting: A Scottish perspective.

PubMed

Parcell, Benjamin J; Jarchow-MacDonald, Anna A; Seagar, Amie-Louise; Laurenson, Ian F; Prescott, Gordon J; Lockhart, Michael

2017-05-01

Xpert MTB/RIF (Cepheid) is a rapid molecular assay shown to be sensitive and specific for pulmonary tuberculosis (TB) diagnosis in highly endemic countries. We evaluated its diagnostic performance in a low TB prevalence setting, examined rifampicin resistance detection and quantitative capabilities predicting graded auramine microscopy and time to positivity (TTP) of culture. Xpert MTB/RIF was used to test respiratory samples over a 3 year period. Samples underwent graded auramine microscopy, solid/liquid culture, in-house IS6110 real-time PCR, and GenoType MTBDRplus (HAIN Lifescience) to determine rifampicin and/or isoniazid resistance. A total of 2103 Xpert MTB/RIF tests were performed. Compared to culture sensitivity was 95.8%, specificity 99.5%, positive predictive value (PPV) 82.1%, and negative predictive value (NPV) 99.9%. A positive correlation was found between auramine microscopy grade and Xpert MTB/RIF assay load. We found a clear reduction in the median TTP as Xpert MTB/RIF assay load increased. Rifampicin resistance was detected. Xpert MTB/RIF was rapid and accurate in diagnosing pulmonary TB in a low prevalence area. Rapid results will influence infection prevention and control and treatment measures. The excellent NPV obtained suggests further work should be carried out to assess its role in replacing microscopy. Copyright © 2017 The British Infection Association. Published by Elsevier Ltd. All rights reserved.

Loss of Atrx Sensitizes Cells to DNA Damaging Agents through p53-Mediated Death Pathways

PubMed Central

Conte, Damiano; Huh, Michael; Goodall, Emma; Delorme, Marilyne; Parks, Robin J.; Picketts, David J.

2012-01-01

Prevalent cell death in forebrain- and Sertoli cell-specific Atrx knockout mice suggest that Atrx is important for cell survival. However, conditional ablation in other tissues is not associated with increased death indicating that diverse cell types respond differently to the loss of this chromatin remodeling protein. Here, primary macrophages isolated from Atrx f/f mice were infected with adenovirus expressing Cre recombinase or β-galactosidase, and assayed for cell survival under different experimental conditions. Macrophages survive without Atrx but undergo rapid apoptosis upon lipopolysaccharide (LPS) activation suggesting that chromatin reorganization in response to external stimuli is compromised. Using this system we next tested the effect of different apoptotic stimuli on cell survival. We observed that survival of Atrx-null cells were similar to wild type cells in response to serum withdrawal, anti-Fas antibody, C2 ceramide or dexamethasone treatment but were more sensitive to 5-fluorouracil (5-FU). Cell survival could be rescued by re-introducing Atrx or by removal of p53 demonstrating the cell autonomous nature of the effect and its p53-dependence. Finally, we demonstrate that multiple primary cell types (myoblasts, embryonic fibroblasts and neurospheres) were sensitive to 5-FU, cisplatin, and UV light treatment. Together, our results suggest that cells lacking Atrx are more sensitive to DNA damaging agents and that this may result in enhanced death during development when cells are at their proliferative peak. Moreover, it identifies potential treatment options for cancers associated with ATRX mutations, including glioblastoma and pancreatic neuroendocrine tumors. PMID:23284920

Loss of Atrx sensitizes cells to DNA damaging agents through p53-mediated death pathways.

PubMed

Conte, Damiano; Huh, Michael; Goodall, Emma; Delorme, Marilyne; Parks, Robin J; Picketts, David J

2012-01-01

Prevalent cell death in forebrain- and Sertoli cell-specific Atrx knockout mice suggest that Atrx is important for cell survival. However, conditional ablation in other tissues is not associated with increased death indicating that diverse cell types respond differently to the loss of this chromatin remodeling protein. Here, primary macrophages isolated from Atrx(f/f) mice were infected with adenovirus expressing Cre recombinase or β-galactosidase, and assayed for cell survival under different experimental conditions. Macrophages survive without Atrx but undergo rapid apoptosis upon lipopolysaccharide (LPS) activation suggesting that chromatin reorganization in response to external stimuli is compromised. Using this system we next tested the effect of different apoptotic stimuli on cell survival. We observed that survival of Atrx-null cells were similar to wild type cells in response to serum withdrawal, anti-Fas antibody, C2 ceramide or dexamethasone treatment but were more sensitive to 5-fluorouracil (5-FU). Cell survival could be rescued by re-introducing Atrx or by removal of p53 demonstrating the cell autonomous nature of the effect and its p53-dependence. Finally, we demonstrate that multiple primary cell types (myoblasts, embryonic fibroblasts and neurospheres) were sensitive to 5-FU, cisplatin, and UV light treatment. Together, our results suggest that cells lacking Atrx are more sensitive to DNA damaging agents and that this may result in enhanced death during development when cells are at their proliferative peak. Moreover, it identifies potential treatment options for cancers associated with ATRX mutations, including glioblastoma and pancreatic neuroendocrine tumors.

Rapid Diagnosis of Bloodstream Infections with PCR Followed by Mass Spectrometry

PubMed Central

Jordana-Lluch, Elena; Carolan, Heather E.; Giménez, Montserrat; Sampath, Rangarajan; Ecker, David J.; Quesada, M. Dolores; Mòdol, Josep M.; Arméstar, Fernando; Blyn, Lawrence B.; Cummins, Lendell L.; Ausina, Vicente; Martró, Elisa

2013-01-01

Achieving a rapid microbiological diagnosis is crucial for decreasing morbidity and mortality of patients with a bloodstream infection, as it leads to the administration of an appropriate empiric antimicrobial therapy. Molecular methods may offer a rapid alternative to conventional microbiological diagnosis involving blood culture. In this study, the performance of a new technology that uses broad-spectrum PCR coupled with mass spectrometry (PCR/ESI-MS) was evaluated for the detection of microorganisms directly from whole blood. A total of 247 whole blood samples and paired blood cultures were prospectively obtained from 175 patients with a suspicion of sepsis. Both sample types were analyzed using the PCR/ESI-MS technology, and the results were compared with those obtained by conventional identification methods. The overall agreement between conventional methods and PCR/ESI-MS performed in blood culture aliquots was 94.2% with 96.8% sensitivity and 98.5% specificity for the molecular method. When comparing conventional methods with PCR/ESI-MS performed in whole blood specimens, the overall agreement was 77.1% with 50% sensitivity and 93.8% specificity for the molecular method. Interestingly, the PCR/ESI-MS technology led to the additional identification of 13 pathogens that were not found by conventional methods. Using the PCR/ESI-MS technology the microbiological diagnosis of bloodstream infections could be anticipated in about half of the patients in our setting, including a small but significant proportion of patients newly diagnosed. Thus, this promising technology could be very useful for the rapid diagnosis of sepsis in combination with traditional methods. PMID:23626775

The Effects of Breakfast Consumption and Composition on Metabolic Wellness with a Focus on Carbohydrate Metabolism.

PubMed

Maki, Kevin C; Phillips-Eakley, Alyssa K; Smith, Kristen N

2016-05-01

Findings from epidemiologic studies indicate that there are associations between breakfast consumption and a lower risk of type 2 diabetes mellitus (T2DM) and metabolic syndrome, prompting interest in the influence of breakfast on carbohydrate metabolism and indicators of T2DM risk. The objective of this review was to summarize the available evidence from randomized controlled trials assessing the impact of breakfast on variables related to carbohydrate metabolism and metabolic wellness. Consuming compared with skipping breakfast appeared to improve glucose and insulin responses throughout the day. Breakfast composition may also be important. Dietary patterns high in rapidly available carbohydrate were associated with elevated T2DM risk. Therefore, partial replacement of rapidly available carbohydrate with other dietary components, such as whole grains and cereal fibers, proteins, and unsaturated fatty acids (UFAs), at breakfast may be a useful strategy for producing favorable metabolic outcomes. Consumption of fermentable and viscous dietary fibers at breakfast lowers glycemia and insulinemia. Fermentable fibers likely act through enhancing insulin sensitivity later in the day, and viscous fibers have an acute effect to slow the rate of carbohydrate absorption. Partially substituting protein for rapidly available carbohydrate enhances satiety and diet-induced thermogenesis, and also favorably affects lipoprotein lipids and blood pressure. Partially substituting UFA for carbohydrate has been associated with improved insulin sensitivity, lipoprotein lipids, and blood pressure. Overall, the available evidence suggests that consuming breakfast foods high in whole grains and cereal fiber, while limiting rapidly available carbohydrate, is a promising strategy for metabolic health promotion. © 2016 American Society for Nutrition.

Surface immuno-functionalisation for the capture and detection of Vibrio species in the marine environment: a new management tool for industrial facilities.

PubMed

Laczka, Olivier F; Labbate, Maurizio; Seymour, Justin R; Bourne, David G; Fielder, Stewart S; Doblin, Martina A

2014-01-01

Bacteria from the genus Vibrio are a common and environmentally important group of bacteria within coastal environments and include species pathogenic to aquaculture organisms. Their distribution and abundance are linked to specific environmental parameters, including temperature, salinity and nutrient enrichment. Accurate and efficient detection of Vibrios in environmental samples provides a potential important indicator of overall ecosystem health while also allowing rapid management responses for species pathogenic to humans or species implicated in disease of economically important aquacultured fish and invertebrates. In this study, we developed a surface immuno-functionalisation protocol, based on an avidin-biotin type covalent binding strategy, allowing specific sandwich-type detection of bacteria from the Vibrio genus. The assay was optimized on 12 diverse Vibrio strains, including species that have implications for aquaculture industries, reaching detection limits between 7×10(3) to 3×10(4) cells mL(-1). Current techniques for the detection of total Vibrios rely on laborious or inefficient analyses resulting in delayed management decisions. This work represents a novel approach for a rapid, accurate, sensitive and robust tool for quantifying Vibrios directly in industrial systems and in the environment, thereby facilitating rapid management responses.

A multiplex lateral flow immunoassay for the rapid identification of NDM-, KPC-, IMP- and VIM-type and OXA-48-like carbapenemase-producing Enterobacteriaceae

PubMed Central

Boutal, Hervé; Vogel, Anaïs; Bernabeu, Sandrine; Devilliers, Karine; Creton, Elodie; Cotellon, Garence; Plaisance, Marc; Oueslati, Saoussen; Dortet, Laurent; Jousset, Agnès; Simon, Stéphanie; Naas, Thierry; Volland, Hervé

2018-01-01

Abstract Objectives The global spread of carbapenemase-producing Enterobacteriaceae represents a substantial challenge in clinical practice and rapid and reliable detection of these organisms is essential. The aim of this study was to develop and validate a lateral flow immunoassay (Carba5) for the detection of the five main carbapenemases (KPC-, NDM-, VIM- and IMP-type and OXA-48-like). Methods Carba5 was retrospectively and prospectively evaluated using 296 enterobacterial isolates from agar culture. An isolated colony was suspended in extraction buffer and then loaded on the manufactured Carba5. Results All 185 isolates expressing a carbapenemase related to one of the Carba5 targets were correctly and unambiguously detected in <15 min. All other isolates gave negative results except those producing OXA-163 and OXA-405, which are considered low-activity carbapenemases. No cross-reaction was observed with non-targeted carbapenemases, ESBLs, AmpCs or oxacillinases (OXA-1, -2, -9 and -10). Overall, this assay reached 100% sensitivity and 95.3% (retrospectively) to 100% (prospectively) specificity. Conclusions Carba5 is efficient, rapid and easy to implement in the routine workflow of a clinical microbiology laboratory for confirmation of the five main carbapenemases encountered in Enterobacteriaceae. PMID:29365094

Sensitivity and rapidity of vegetational response to abrupt climate change

NASA Technical Reports Server (NTRS)

Peteet, D.

2000-01-01

Rapid climate change characterizes numerous terrestrial sediment records during and since the last glaciation. Vegetational response is best expressed in terrestrial records near ecotones, where sensitivity to climate change is greatest, and response times are as short as decades.

Application of Fourier transform near-infrared spectroscopy combined with high-performance liquid chromatography in rapid and simultaneous determination of essential components in crude Radix Scrophulariae.

PubMed

Li, Xiaomeng; Fang, Dansi; Cong, Xiaodong; Cao, Gang; Cai, Hao; Cai, Baochang

2012-12-01

A method is described using rapid and sensitive Fourier transform near-infrared spectroscopy combined with high-performance liquid chromatography-diode array detection for the simultaneous identification and determination of four bioactive compounds in crude Radix Scrophulariae samples. Partial least squares regression is selected as the analysis type and multiplicative scatter correction, second derivative, and Savitzky-Golay filter were adopted for the spectral pretreatment. The correlation coefficients (R) of the calibration models were above 0.96 and the root mean square error of predictions were under 0.028. The developed models were applied to unknown samples with satisfactory results. The established method was validated and can be applied to the intrinsic quality control of crude Radix Scrophulariae.

Laboratory investigation of a multistate food-borne outbreak of Escherichia coli O157:H7 by using pulsed-field gel electrophoresis and phage typing.

PubMed Central

Barrett, T J; Lior, H; Green, J H; Khakhria, R; Wells, J G; Bell, B P; Greene, K D; Lewis, J; Griffin, P M

1994-01-01

Two hundred thirty-three isolates of Escherichia coli O157:H7 were analyzed by both pulsed-field gel electrophoresis (PFGE) and bacteriophage typing. All 26 isolates from persons whose illness was associated with a recent multistate outbreak of E. coli O157:H7 infections linked to the consumption of undercooked hamburgers and all 27 isolates from incriminated lots of hamburger meat had the same phage type and the same PFGE pattern. Twenty-five of 74 E. coli O157:H7 isolates from Washington State and 10 of 27 isolates from other states obtained during the 6 months before the outbreak had the same phage type as the outbreak strain, but only 1 isolate had the same PFGE pattern. PFGE thus appeared to be a more sensitive method than bacteriophage typing for distinguishing outbreak and non-outbreak-related strains. The PFGE patterns of seven preoutbreak sporadic isolates and five sporadic isolates from the outbreak period differed from that of the outbreak strain by a single band, making it difficult to identify these isolates as outbreak or non-outbreak related. Phage typing and PFGE with additional enzymes were helpful in resolving this problem. While not as sensitive as PFGE, phage typing was helpful in interpreting PFGE data and could have been used as a simple, rapid screen to eliminate the need for performing PFGE on unrelated isolates. Images PMID:7883892

Performance of mid infrared spectroscopy in skin cancer cell type identification

NASA Astrophysics Data System (ADS)

Kastl, Lena; Kemper, Björn; Lloyd, Gavin R.; Nallala, Jayakrupakar; Stone, Nick; Naranjo, Valery; Penaranda, Francisco; Schnekenburger, Jürgen

2017-02-01

Marker free optical spectroscopy is a powerful tool for the rapid inspection of pathologically suspicious skin lesions and the non-invasive detection of early skin tumors. This goal can be reached by the combination of signal localization and the spectroscopical detection of chemical cell signatures. We here present the development and application of mid infrared spectroscopy (midIR) for the analysis of skin tumor cell types and three dimensional tissue phantoms towards the application of midIR spectroscopy for fast and reliable skin diagnostics. We developed standardized in vitro skin systems with increasing complexity, from single skin cell types as fibroblasts, keratinocytes and melanoma cells, to mixtures of these and finally three dimensional skin cancer phantoms. The cell systems were characterized with different systems in the midIR range up to 12 μm. The analysis of the spectra by novel data processing algorithms demonstrated the clear separation of all cell types, especially melanoma cells. Special attention and algorithm training was required for closely related mesenchymal cell types as dedifferentiated melanoma cells and fibroblasts. Proof of concept experiments with mixtures of in vivo fluorescence labelled skin cell types allowed the test of the new algorithms performance for the identification of specific cell types. The intense training of the software systems with various samples resulted in a increased sensitivity and specificity of the combined midIR and software system. These data highlight the potential of midIR spectroscopy as sensitive and specific future optical biopsy technology.

Assessment of RapidEye vegetation indices for estimation of leaf area index and biomass in corn and soybean crops

NASA Astrophysics Data System (ADS)

Kross, Angela; McNairn, Heather; Lapen, David; Sunohara, Mark; Champagne, Catherine

2015-02-01

Leaf area index (LAI) and biomass are important indicators of crop development and the availability of this information during the growing season can support farmer decision making processes. This study demonstrates the applicability of RapidEye multi-spectral data for estimation of LAI and biomass of two crop types (corn and soybean) with different canopy structure, leaf structure and photosynthetic pathways. The advantages of Rapid Eye in terms of increased temporal resolution (∼daily), high spatial resolution (∼5 m) and enhanced spectral information (includes red-edge band) are explored as an individual sensor and as part of a multi-sensor constellation. Seven vegetation indices based on combinations of reflectance in green, red, red-edge and near infrared bands were derived from RapidEye imagery between 2011 and 2013. LAI and biomass data were collected during the same period for calibration and validation of the relationships between vegetation indices and LAI and dry above-ground biomass. Most indices showed sensitivity to LAI from emergence to 8 m2/m2. The normalized difference vegetation index (NDVI), the red-edge NDVI and the green NDVI were insensitive to crop type and had coefficients of variations (CV) ranging between 19 and 27%; and coefficients of determination ranging between 86 and 88%. The NDVI performed best for the estimation of dry leaf biomass (CV = 27% and r2 = 090) and was also insensitive to crop type. The red-edge indices did not show any significant improvement in LAI and biomass estimation over traditional multispectral indices. Cumulative vegetation indices showed strong performance for estimation of total dry above-ground biomass, especially for corn (CV ≤ 20%). This study demonstrated that continuous crop LAI monitoring over time and space at the field level can be achieved using a combination of RapidEye, Landsat and SPOT data and sensor-dependant best-fit functions. This approach eliminates/reduces the need for reflectance resampling, VIs inter-calibration and spatial resampling.

Flexibility of rapid-acting insulin analogues in children and adolescents with diabetes mellitus.

PubMed

Danne, Thomas

2007-01-01

Every year, approximately 70,000 children aged<15 years develop type 1 diabetes mellitus (DM) worldwide. Achieving glycosylated hemoglobin control is a very important aim, but quality-of-life concerns for the child and the family should also have high priority in the management of pediatric DM. This review outlines some of the issues involved in treating type 1 DM in children and adolescents, as well as the use of rapid-acting insulin analogues in basal-bolus therapy and continuous subcutaneous insulin infusion pumps. This review article was based on a presentation at a satellite symposium entitled "Realising the Value of Modern Insulins: Reaching Further with Rapid-Acting Insulin Analogues "that was convened during the XIXth World Diabetes Congress, December 3, 2006, in Cape Town, South Africa. Treating children and adolescents with DM is a challenge that should not be ignored. Furthermore, DM in children is quite different from that in adults. Numerous factors have to be taken into account when evaluating treatment for children with DM in comparison with treatment for adult DM: sleep patterns; unpredictable activities, especially eating behaviors; limited size of injection sites, making it difficult to rotate injections; higher insulin sensitivity; and frequent infectious diseases. In addition, achieving normal psychosocial development may be just as important as achieving strict metabolic control in this population. Rapid-acting insulin analogues can be used effectively in these individuals with type 1 DM. The pharmacokinetic profile of insulin aspart suggests that it is suitable for flexible mealtime administration in children and adolescents. Indeed, clinical studies in children and adolescents have shown the efficacy and tolerability of postprandial administration of insulin aspart, particularly in comparison with soluble human insulin. Postprandial administration of insulin aspart, compared with preprandial soluble human insulin, has also been studied in very young children (aged 2-6 years); similar metabolic control and increased parent preference for insulin aspart were reported. Rapid-acting insulin analogues in children and adolescents with type 1 DM are effective and well tolerated; they can be injected postprandially, and this is a reliable option that can be recommended to patients and their families.

Rapid Recycling of Ca2+ between IP3-Sensitive Stores and Lysosomes

PubMed Central

López Sanjurjo, Cristina I.; Tovey, Stephen C.; Taylor, Colin W.

2014-01-01

Inositol 1,4,5-trisphosphate (IP3) evokes release of Ca2+ from the endoplasmic reticulum (ER), but the resulting Ca2+ signals are shaped by interactions with additional intracellular organelles. Bafilomycin A1, which prevents lysosomal Ca2+ uptake by inhibiting H+ pumping into lysosomes, increased the amplitude of the initial Ca2+ signals evoked by carbachol in human embryonic kidney (HEK) cells. Carbachol alone and carbachol in combination with parathyroid hormone (PTH) evoke Ca2+ release from distinct IP3-sensitive Ca2+ stores in HEK cells stably expressing human type 1 PTH receptors. Bafilomycin A1 similarly exaggerated the Ca2+ signals evoked by carbachol or carbachol with PTH, indicating that Ca2+ released from distinct IP3-sensitive Ca2+ stores is sequestered by lysosomes. The Ca2+ signals resulting from store-operated Ca2+ entry, whether evoked by thapsigargin or carbachol, were unaffected by bafilomycin A1. Using Gd3+ (1 mM) to inhibit both Ca2+ entry and Ca2+ extrusion, HEK cells were repetitively stimulated with carbachol to assess the effectiveness of Ca2+ recycling to the ER after IP3-evoked Ca2+ release. Blocking lysosomal Ca2+ uptake with bafilomycin A1 increased the amplitude of each carbachol-evoked Ca2+ signal without affecting the rate of Ca2+ recycling to the ER. This suggests that Ca2+ accumulated by lysosomes is rapidly returned to the ER. We conclude that lysosomes rapidly, reversibly and selectively accumulate the Ca2+ released by IP3 receptors residing within distinct Ca2+ stores, but not the Ca2+ entering cells via receptor-regulated, store-operated Ca2+ entry pathways. PMID:25337829

Rapid recycling of Ca2+ between IP3-sensitive stores and lysosomes.

PubMed

López Sanjurjo, Cristina I; Tovey, Stephen C; Taylor, Colin W

2014-01-01

Inositol 1,4,5-trisphosphate (IP3) evokes release of Ca2+ from the endoplasmic reticulum (ER), but the resulting Ca2+ signals are shaped by interactions with additional intracellular organelles. Bafilomycin A1, which prevents lysosomal Ca2+ uptake by inhibiting H+ pumping into lysosomes, increased the amplitude of the initial Ca2+ signals evoked by carbachol in human embryonic kidney (HEK) cells. Carbachol alone and carbachol in combination with parathyroid hormone (PTH) evoke Ca2+ release from distinct IP3-sensitive Ca2+ stores in HEK cells stably expressing human type 1 PTH receptors. Bafilomycin A1 similarly exaggerated the Ca2+ signals evoked by carbachol or carbachol with PTH, indicating that Ca2+ released from distinct IP3-sensitive Ca2+ stores is sequestered by lysosomes. The Ca2+ signals resulting from store-operated Ca2+ entry, whether evoked by thapsigargin or carbachol, were unaffected by bafilomycin A1. Using Gd3+ (1 mM) to inhibit both Ca2+ entry and Ca2+ extrusion, HEK cells were repetitively stimulated with carbachol to assess the effectiveness of Ca2+ recycling to the ER after IP3-evoked Ca2+ release. Blocking lysosomal Ca2+ uptake with bafilomycin A1 increased the amplitude of each carbachol-evoked Ca2+ signal without affecting the rate of Ca2+ recycling to the ER. This suggests that Ca2+ accumulated by lysosomes is rapidly returned to the ER. We conclude that lysosomes rapidly, reversibly and selectively accumulate the Ca2+ released by IP3 receptors residing within distinct Ca2+ stores, but not the Ca2+ entering cells via receptor-regulated, store-operated Ca2+ entry pathways.

Variation in soil aluminium tolerance genes is associated with local adaptation to soils at the Park Grass Experiment.

PubMed

Gould, Billie; McCouch, Susan; Geber, Monica

2014-12-01

Studies of the wild grass Anthoxanthum odoratum at the long-term Park Grass Experiment (PGE, Harpenden, UK) document a well-known example of rapid plant evolution in response to environmental change. Repeated fertilizer applications have acidified the soil in some experimental plots over the past 150+ years, and Anthoxanthum subpopulations have quickly become locally adapted. Early reciprocal transplants showed subpopulation differentiation specifically in response to soil aluminium (Al) toxicity across the experiment, even at small (30 m) spatial scales. Almost 40 years after its original measurement, we reassessed the degree of local adaptation to soil Al at the PGE using updated phenotyping methods and identified genes with variation linked to the tolerance trait. Root growth assays show that plants are locally adapted to soil Al at both the seedling and adult growth stages, but to a smaller extent than previously inferred. Among a large suite of candidate loci that were previously shown to have Al-sensitive expression differences between sensitive and tolerant plants, three loci contained SNPs that are associated with both Al tolerance and soil acidity: an Al-sensitive malate transporter (ALMT), a tonoplast intrinsic protein (TIP) and the putative homolog of the rice cell-wall modification gene STAR1. Natural genetic variation at these loci is likely to have contributed to the recent rapid evolution at PGE. Continued study of Al tolerance variants in Anthoxanthum will allow us to test hypotheses about the nature and source of genetic variation that enables some species to adapt to soil acidification and other types of rapid environmental change. © 2014 John Wiley & Sons Ltd.

The thermo-sensitive gene expression signatures of spermatogenesis.

PubMed

Yadav, Santosh K; Pandey, Aastha; Kumar, Lokesh; Devi, Archana; Kushwaha, Bhavana; Vishvkarma, Rahul; Maikhuri, Jagdamba P; Rajender, Singh; Gupta, Gopal

2018-06-02

Spermatogenesis in most mammals (including human and rat) occurs at ~ 3 °C lower than body temperature in a scrotum and fails rapidly at 37 °C inside the abdomen. The present study investigates the heat-sensitive transcriptome and miRNAs in the most vulnerable germ cells (spermatocytes and round spermatids) that are primarily targeted at elevated temperature in a bid to identify novel targets for contraception and/or infertility treatment. Testes of adult male rats subjected to surgical cryptorchidism were obtained at 0, 24, 72 and 120 h post-surgery, followed by isolation of primary spermatocytes and round spermatids and purification to > 90% purity using a combination of trypsin digestion, centrifugal elutriation and density gradient centrifugation techniques. RNA isolated from these cells was sequenced by massive parallel sequencing technique to identify the most-heat sensitive mRNAs and miRNAs. Heat stress altered the expression of a large number of genes by ≥2.0 fold, out of which 594 genes (286↑; 308↓) showed alterations in spermatocytes and 154 genes (105↑; 49↓) showed alterations in spermatids throughout the duration of experiment. 62 heat-sensitive genes were common to both cell types. Similarly, 66 and 60 heat-sensitive miRNAs in spermatocytes and spermatids, respectively, were affected by ≥1.5 fold, out of which 6 were common to both the cell types. The study has identified Acly, selV, SLC16A7(MCT-2), Txnrd1 and Prkar2B as potential heat sensitive targets in germ cells, which may be tightly regulated by heat sensitive miRNAs rno-miR-22-3P, rno-miR-22-5P, rno-miR-129-5P, rno-miR-3560, rno-miR-3560 and rno-miR-466c-5P.

Colonization of fish skin is vital for Vibrio anguillarum to cause disease.

PubMed

Weber, Barbara; Chen, Chang; Milton, Debra L

2010-02-01

Vibrio anguillarum causes a fatal haemorrhagic septicaemia in marine fish. During initial stages of infection, host surfaces are colonized; however, few virulence factors required for colonization of the host are identified. In this study, in vivo bioluminescent imaging was used to analyse directly the colonization of the whole rainbow trout animal by V. anguillarum. The wild type rapidly colonized both the skin and the intestines by 24 h; however, the bacterial numbers on the skin were significantly higher than in the intestines indicating that skin colonization may be important for disease to occur. Mutants defective for the anguibactin iron uptake system, exopolysaccharide transport, or Hfq, an RNA chaperone, were attenuated for virulence, did not colonize the skin, and penetrated skin mucus less efficiently than the wild type. These mutants, however, did colonize the intestines and were as resistant to 2% bile salts as is the wild type. Moreover, exopolysaccharide mutants were significantly more sensitive to lysozyme and antimicrobial peptides, while the Hfq and anguibactin mutants were sensitive to lysozyme compared with the wild type. Vibrio anguillarum encodes several mechanisms to protect against antimicrobial components of skin mucus enabling an amazingly abundant growth on the skin enhancing its disease opportunities. © 2010 Society for Applied Microbiology and Blackwell Publishing Ltd.

Multiplex Touchdown PCR for Rapid Typing of the Opportunistic Pathogen Propionibacterium acnes

PubMed Central

Barnard, Emma; Nagy, István; Hunyadkürti, Judit; Patrick, Sheila

2015-01-01

The opportunistic human pathogen Propionibacterium acnes is composed of a number of distinct phylogroups, designated types IA1, IA2, IB, IC, II, and III, which vary in their production of putative virulence factors, their inflammatory potential, and their biochemical, aggregative, and morphological characteristics. Although multilocus sequence typing (MLST) currently represents the gold standard for unambiguous phylogroup classification and individual strain identification, it is a labor-intensive and time-consuming technique. As a consequence, we developed a multiplex touchdown PCR assay that in a single reaction can confirm the species identity and phylogeny of an isolate based on its pattern of reaction with six primer sets that target the 16S rRNA gene (all isolates), ATPase (types IA1, IA2, and IC), sodA (types IA2 and IB), atpD (type II), and recA (type III) housekeeping genes, as well as a Fic family toxin gene (type IC). When applied to 312 P. acnes isolates previously characterized by MLST and representing types IA1 (n = 145), IA2 (n = 20), IB (n = 65), IC (n = 7), II (n = 45), and III (n = 30), the multiplex displayed 100% sensitivity and 100% specificity for detecting isolates within each targeted phylogroup. No cross-reactivity with isolates from other bacterial species was observed. This multiplex assay will provide researchers with a rapid, high-throughput, and technically undemanding typing method for epidemiological and phylogenetic investigations. It will facilitate studies investigating the association of lineages with various infections and clinical conditions, and it will serve as a prescreening tool to maximize the number of genetically diverse isolates selected for downstream higher-resolution sequence-based analyses. PMID:25631794

Digital sensing and sizing of vesicular stomatitis virus pseudotypes in complex media: a model for Ebola and Marburg detection.

PubMed

Daaboul, George G; Lopez, Carlos A; Chinnala, Jyothsna; Goldberg, Bennett B; Connor, John H; Ünlü, M Selim

2014-06-24

Rapid, sensitive, and direct label-free capture and characterization of nanoparticles from complex media such as blood or serum will broadly impact medicine and the life sciences. We demonstrate identification of virus particles in complex samples for replication-competent wild-type vesicular stomatitis virus (VSV), defective VSV, and Ebola- and Marburg-pseudotyped VSV with high sensitivity and specificity. Size discrimination of the imaged nanoparticles (virions) allows differentiation between modified viruses having different genome lengths and facilitates a reduction in the counting of nonspecifically bound particles to achieve a limit-of-detection (LOD) of 5 × 10(3) pfu/mL for the Ebola and Marburg VSV pseudotypes. We demonstrate the simultaneous detection of multiple viruses in a single sample (composed of serum or whole blood) for screening applications and uncompromised detection capabilities in samples contaminated with high levels of bacteria. By employing affinity-based capture, size discrimination, and a "digital" detection scheme to count single virus particles, we show that a robust and sensitive virus/nanoparticle sensing assay can be established for targets in complex samples. The nanoparticle microscopy system is termed the Single Particle Interferometric Reflectance Imaging Sensor (SP-IRIS) and is capable of high-throughput and rapid sizing of large numbers of biological nanoparticles on an antibody microarray for research and diagnostic applications.

A broad range assay for rapid detection and etiologic characterization of bacterial meningitis: performance testing in samples from sub-Sahara.

PubMed

Won, Helen; Yang, Samuel; Gaydos, Charlotte; Hardick, Justin; Ramachandran, Padmini; Hsieh, Yu-Hsiang; Kecojevic, Alexander; Njanpop-Lafourcade, Berthe-Marie; Mueller, Judith E; Tameklo, Tsidi Agbeko; Badziklou, Kossi; Gessner, Bradford D; Rothman, Richard E

2012-09-01

This study aimed to conduct a pilot evaluation of broad-based multiprobe polymerase chain reaction (PCR) in clinical cerebrospinal fluid (CSF) samples compared to local conventional PCR/culture methods used for bacterial meningitis surveillance. A previously described PCR consisting of initial broad-based detection of Eubacteriales by a universal probe, followed by Gram typing, and pathogen-specific probes was designed targeting variable regions of the 16S rRNA gene. The diagnostic performance of the 16S rRNA assay in "127 CSF samples was evaluated in samples from patients from Togo, Africa, by comparison to conventional PCR/culture methods. Our probes detected Neisseria meningitidis, Streptococcus pneumoniae, and Haemophilus influenzae. Uniprobe sensitivity and specificity versus conventional PCR were 100% and 54.6%, respectively. Sensitivity and specificity of uniprobe versus culture methods were 96.5% and 52.5%, respectively. Gram-typing probes correctly typed 98.8% (82/83) and pathogen-specific probes identified 96.4% (80/83) of the positives. This broad-based PCR algorithm successfully detected and provided species level information for multiple bacterial meningitis agents in clinical samples. Copyright © 2012 Elsevier Inc. All rights reserved.

A broad range assay for rapid detection and etiologic characterization of bacterial meningitis: performance testing in samples from sub-Sahara☆, ☆☆,★

PubMed Central

Won, Helen; Yang, Samuel; Gaydos, Charlotte; Hardick, Justin; Ramachandran, Padmini; Hsieh, Yu-Hsiang; Kecojevic, Alexander; Njanpop-Lafourcade, Berthe-Marie; Mueller, Judith E.; Tameklo, Tsidi Agbeko; Badziklou, Kossi; Gessner, Bradford D.; Rothman, Richard E.

2012-01-01

This study aimed to conduct a pilot evaluation of broad-based multiprobe polymerase chain reaction (PCR) in clinical cerebrospinal fluid (CSF) samples compared to local conventional PCR/culture methods used for bacterial meningitis surveillance. A previously described PCR consisting of initial broad-based detection of Eubacteriales by a universal probe, followed by Gram typing, and pathogen-specific probes was designed targeting variable regions of the 16S rRNA gene. The diagnostic performance of the 16S rRNA assay in “”127 CSF samples was evaluated in samples from patients from Togo, Africa, by comparison to conventional PCR/culture methods. Our probes detected Neisseria meningitidis, Streptococcus pneumoniae, and Haemophilus influenzae. Uniprobe sensitivity and specificity versus conventional PCR were 100% and 54.6%, respectively. Sensitivity and specificity of uniprobe versus culture methods were 96.5% and 52.5%, respectively. Gram-typing probes correctly typed 98.8% (82/83) and pathogen-specific probes identified 96.4% (80/83) of the positives. This broad-based PCR algorithm successfully detected and provided species level information for multiple bacterial meningitis agents in clinical samples. PMID:22809694

Sensitive and Specific Fluorescent Probes for Functional Analysis of the Three Major Types of Mammalian ABC Transporters

PubMed Central

Lebedeva, Irina V.; Pande, Praveen; Patton, Wayne F.

2011-01-01

An underlying mechanism for multi drug resistance (MDR) is up-regulation of the transmembrane ATP-binding cassette (ABC) transporter proteins. ABC transporters also determine the general fate and effect of pharmaceutical agents in the body. The three major types of ABC transporters are MDR1 (P-gp, P-glycoprotein, ABCB1), MRP1/2 (ABCC1/2) and BCRP/MXR (ABCG2) proteins. Flow cytometry (FCM) allows determination of the functional expression levels of ABC transporters in live cells, but most dyes used as indicators (rhodamine 123, DiOC2(3), calcein-AM) have limited applicability as they do not detect all three major types of ABC transporters. Dyes with broad coverage (such as doxorubicin, daunorubicin and mitoxantrone) lack sensitivity due to overall dimness and thus may yield a significant percentage of false negative results. We describe two novel fluorescent probes that are substrates for all three common types of ABC transporters and can serve as indicators of MDR in flow cytometry assays using live cells. The probes exhibit fast internalization, favorable uptake/efflux kinetics and high sensitivity of MDR detection, as established by multidrug resistance activity factor (MAF) values and Kolmogorov-Smirnov statistical analysis. Used in combination with general or specific inhibitors of ABC transporters, both dyes readily identify functional efflux and are capable of detecting small levels of efflux as well as defining the type of multidrug resistance. The assay can be applied to the screening of putative modulators of ABC transporters, facilitating rapid, reproducible, specific and relatively simple functional detection of ABC transporter activity, and ready implementation on widely available instruments. PMID:21799851

Isothermal Method of a Recombinase Polymerase Amplification Assay for the Detection of Most Common High-Risk Human Papillomavirus Type 16 and Type 18 DNA.

PubMed

Ma, Biao; Fang, Jiehong; Wang, Ye; He, Haizhen; Dai, Mingyan; Lin, Wei; Su, Wei; Zhang, Mingzhou

2017-01-01

Cervical cancer is a common gynecologic malignant tumor and has a great impact on women's health. Human papillomavirus (HPV) is implicated in cervical cancer and precancerous lesions and the two are possibly two stages of disease progression. With the technological development of molecular biology and epidemiology, detection and treatment of HPV has become an important means to prevent cervical cancer. Here we present a novel, rapid, sensitive and specific isothermal method of recombinase polymerase amplification (RPA), which is established to detect the two most common high-risk human papillomavirus type 16 and type 18 DNA. In this study, we evaluate the efficacy of the RPA assay, incubating clinical specimens of HPV16 and HPV18 using plasmids standard. It operates at constant low temperature without the thermal instrumentation for incubation. The products can be detected via agarose gel electrophoresis assay, reverse dot blot assay, and quantitative real-time assay with SYBR Green I. We assess the diagnostic performance of the RPA assay for detecting of HPV16 and HPV18 in 335 clinical samples from patients suspected of cervical cancer. The results revealed no cross-reaction with other HPV genotypes and the RPA assay achieve a sensitivity of 100 copies. Compared with TaqMan qPCR, the RPA technique achieves exponential amplification with no need for pretreatment of sample DNA at 37°C for 20 minutes, which reveals more satisfactory performance. The agreement between the RPA and qPCR assays was 97.6% (κ = 0.89) for HPV16 positivity and 98.5% (κ = 0.81) for HPV18 positivity, indicating very good correlation between both tests. Importantly, the RPA assay was demonstrated to be a useful and powerful method for detection of HPV virus, which therefore may serve as a valuable tool for rapid diagnosis of HPV infection in both commercial and clinical applications.

pH-Sensitive PEGylated liposomes functionalized with a fibronectin-mimetic peptide show enhanced intracellular delivery to colon cancer cell.

PubMed

Garg, Ashish; Kokkoli, Efrosini

2011-08-01

pH-sensitive liposomes undergo rapid destabilization under mildly acidic conditions such as those found in endocytotic vesicles. Though this makes them promising drug carriers, their application is limited due to their rapid clearance from circulation by the reticulo-endothelial system. Researchers have therefore used pH-sensitive liposomes that are sterically stabilized by polyethylene glycol (PEG) molecules (stealth liposomes) on the liposome surface. The goal of this study is to bring bio-functionality to pH-sensitive PEGylated liposomes in order to facilitate their potential use as a targeted drug delivery agent. To improve the selectivity of these nanoparticles, we included a targeting moiety, PR_b which specifically recognizes and binds to integrin α(5)β(1) expressing cells. PR_b (KSSPHSRN(SG)(5)RGDSP) is a novel fibronectin-mimetic peptide sequence that mimics the cell adhesion domain of fibronectin. Integrin α(5)β(1) is expressed on several types of cancer cells, including colon cancer, and plays an important role in tumor growth and metastasis. We have thoroughly studied the release of calcein from pH-sensitive PEGylated liposomes by varying the lipid composition of the liposomes in the absence and presence of the targeting peptide, PR_b, and accounting for the first time for the effect of both pH and time (photo-bleaching effect) on the fluorescence signal of calcein. We have demonstrated that we can design PR_b-targeted pH-sensitive PEGylated liposomes, which can undergo destabilization under mildly acidic conditions and have shown that incorporating the PR_b peptide does not significantly affect the pH-sensitivity of the liposomes. PR_b-targeted pH-sensitive PEGylated liposomes bind to CT26.WT colon carcinoma cells that express integrin α(5)β(1), undergo cellular internalization, and release their load intracellularly in a short period of time as compared to other formulations. Our studies demonstrate that PR_b-functionalized pH-sensitive targeted delivery systems have the potential to deliver a payload directly to cancer cells in an efficient and specific manner.

Rapid desensitization induces internalization of antigen-specific IgE on mouse mast cells.

PubMed

Oka, Tatsuya; Rios, Eon J; Tsai, Mindy; Kalesnikoff, Janet; Galli, Stephen J

2013-10-01

Rapid desensitization transiently prevents severe allergic reactions, allowing administration of life-saving therapies in previously sensitized patients. However, the mechanisms underlying successful rapid desensitization are not fully understood. We sought to investigate whether the mast cell (MC) is an important target of rapid desensitization in mice sensitized to exhibit IgE-dependent passive systemic anaphylaxis in vivo and to investigate the antigen specificity and underlying mechanisms of rapid desensitization in our mouse model. C57BL/6 mice (in vivo) or primary isolated C57BL/6 mouse peritoneal mast cells (PMCs; in vitro) were passively sensitized with antigen-specific anti-2,4-dinitrophenyl IgE, anti-ovalbumin IgE, or both. MCs were exposed over a short period of time to increasing amounts of antigen (2,4-dinitrophenyl-human serum albumin or ovalbumin) in the presence of extracellular calcium in vitro or by means of intravenous administration to sensitized mice in vivo before challenging the mice with or exposing the PMCs to optimal amounts of specific or irrelevant antigen. Rapidly exposing mice or PMCs to progressively increasing amounts of specific antigen inhibited the development of antigen-induced hypothermia in sensitized mice in vivo and inhibited antigen-induced PMC degranulation and prostaglandin D2 synthesis in vitro. Such MC hyporesponsiveness was induced antigen-specifically and was associated with a significant reduction in antigen-specific IgE levels on MC surfaces. Rapidly exposing MCs to progressively increasing amounts of antigen can both enhance the internalization of antigen-specific IgE on the MC surface and also desensitize these cells in an antigen-specific manner in vivo and in vitro. Copyright © 2013 American Academy of Allergy, Asthma & Immunology. Published by Mosby, Inc. All rights reserved.

Rapid desensitization induces internalization of antigen-specific IgE on mouse mast cells

PubMed Central

Oka, Tatsuya; Rios, Eon J.; Tsai, Mindy; Kalesnikoff, Janet; Galli, Stephen J.

2013-01-01

Background Rapid desensitization transiently prevents severe allergic reactions, allowing administration of life-saving therapies in previously sensitized patients. However, the mechanisms underlying successful rapid desensitization are not fully understood. Objectives We sought to investigate whether the mast cell (MC) is an important target of rapid desensitization in mice sensitized to exhibit IgE-dependent passive systemic anaphylaxis in vivo and to investigate the antigen specificity and underlying mechanisms of rapid desensitization in our mouse model. Methods C57BL/6 mice (in vivo) or primary isolated C57BL/6 mouse peritoneal mast cells (PMCs; in vitro) were passively sensitized with antigen-specific anti–2,4-dinitrophenyl IgE, anti-ovalbumin IgE, or both. MCs were exposed over a short period of time to increasing amounts of antigen (2,4-dinitrophenyl–human serum albumin or ovalbumin) in the presence of extracellular calcium in vitro or by means of intravenous administration to sensitized mice in vivo before challenging the mice with or exposing the PMCs to optimal amounts of specific or irrelevant antigen. Results Rapidly exposing mice or PMCs to progressively increasing amounts of specific antigen inhibited the development of antigen-induced hypothermia in sensitized mice in vivo and inhibited antigen-induced PMC degranulation and prostaglandin D2 synthesis in vitro. Such MC hyporesponsiveness was induced antigen-specifically and was associated with a significant reduction in antigen-specific IgE levels on MC surfaces. Conclusions Rapidly exposing MCs to progressively increasing amounts of antigen can both enhance the internalization of antigen-specific IgE on the MC surface and also desensitize these cells in an antigen-specific manner in vivo and in vitro. PMID:23810240

Diagnostic accuracy of three monoclonal stool tests in a large series of untreated Helicobacter pylori infected patients.

PubMed

Lario, Sergio; Ramírez-Lázaro, María José; Montserrat, Antònia; Quílez, María Elisa; Junquera, Félix; Martínez-Bauer, Eva; Sanfeliu, Isabel; Brullet, Enric; Campo, Rafael; Segura, Ferran; Calvet, Xavier

2016-06-01

Immunochromatographic tests need to be improved in order to enhance their reliability. Recently, several new kits have appeared on the market. The objective was to evaluate the diagnostic accuracy of three monoclonal rapid stool tests - the new Uni-Gold™ H.pylori Antigen (Trinity Biotech, Ireland), the RAPID Hp StAR (Oxoid Ltd., UK) and the ImmunoCard STAT! HpSA (Meridian Diagnostics, USA) - for detecting H. pylori infection prior to eradication treatment. Diagnostic accuracy (sensitivity and specificity) and reliability (concordance between observers) were evaluated in 250 untreated consecutive dyspeptic patients. The gold standard for diagnosing H. pylori infection was defined as the concordance of two or more of rapid urease test (RUT), histopathology and urease breath test (UBT) or positive culture in isolation. Readings of immunochromatographic tests were performed by two different observers. Sensitivity, specificity, positive and negative predictive values and 95% confidence intervals were calculated. Sensitivity and specificity were compared using the McNemar test. The three tests showed a good correlation, with Kappa values>0.9. RAPID Hp StAR had a sensitivity of 91%-92% and a specificity ranging from 77% to 85%. Its sensitivity was higher than that of Uni-Gold™ H.pylori Antigen and ImmunoCard STAT! HpSA (p<0.01). Uni-Gold™ H.pylori Antigen kit showed a sensitivity of 83%, similar to ImmunoCard STAT! HpSA. Specificity of Uni-Gold™ H.pylori Antigen approached 90% (87-89%) and was superior to that of RAPID Hp StAR (p<0.01). Uni-Gold™ H.pylori Antigen and ImmunoCard STAT! HpSA present similar levels of diagnostic accuracy. RAPID Hp StAR was the most sensitive but less reliable of the three immunochromatographic stool tests. None are as accurate and reliable as UBT, RUT and histology. Copyright © 2016 The Canadian Society of Clinical Chemists. Published by Elsevier Inc. All rights reserved.

Development and comparison of a rapid isothermal nucleic acid amplification test for typing of herpes simplex virus types 1 and 2 on a portable fluorescence detector.

PubMed

Tong, Yanhong; McCarthy, Kaitlin; Kong, Huimin; Lemieux, Bertrand

2012-11-01

We have developed a rapid and simple molecular test, the IsoGlow HSV Typing assay, for the detection and typing of herpes simplex virus (type 1 and 2) from genital or oral lesions. Clinical samples suspended in viral transport mediums are simply diluted and then added to a helicase-dependent amplification master mix. The amplification and detection were performed on a portable fluorescence detector called the FireFly instrument. Detection of amplification products is based on end-point analysis using cycling probe technology. An internal control nucleic acid was included in the amplification master mix to monitor the presence of amplification inhibitors in the samples. Because the device has only two fluorescence detection channels, two strategies were developed and compared to detect the internal control template: internal control detected by melting curve analysis using a dual-labeled probe, versus internal control detection using end-point fluorescence release by a CPT probe at a lower temperature. Both have a total turnaround time of about 1 hour. Clinical performance relative to herpes viral culture was evaluated using 176 clinical specimens. Both formats of the IsoGlow HSV typing assay had sensitivities comparable to that of the Food and Drug Administration-cleared IsoAmp HSV (BioHelix Corp., Beverly MA) test and specificity for the two types of HSV comparable to that of ELVIS HSV (Diagnostic Hybrids, Athens, OH). Copyright © 2012 American Society for Investigative Pathology and the Association for Molecular Pathology. Published by Elsevier Inc. All rights reserved.

Rapid detection of Salmonella in food and feed by coupling loop-mediated isothermal amplification with bioluminescent assay in real-time.

PubMed

Yang, Qianru; Domesle, Kelly J; Wang, Fei; Ge, Beilei

2016-06-17

Salmonella is among the most significant pathogens causing food and feed safety concerns. This study examined the rapid detection of Salmonella in various types of food and feed samples by coupling loop-mediated isothermal amplification (LAMP) with a novel reporter, bioluminescent assay in real-time (BART). Performance of the LAMP-BART assay was compared to a conventional LAMP and the commercially available 3M Molecular Detection Assay (MDA) Salmonella. The LAMP-BART assay was 100 % specific among 178 strains (151 Salmonella and 27 non-Salmonella) tested. The detection limits were 36 cells per reaction in pure culture and 10(4) to 10(6) CFU per 25 g in spiked food and feed samples without enrichment, which were comparable to those of the conventional LAMP and 3M MDA Salmonella but 5-10 min faster. Ground turkey showed a strong inhibition on 3M MDA Salmonella, requiring at least 10(8) CFU per 25 g for detection. The correlation between Salmonella cell numbers and LAMP-BART signals was high (R (2) = 0.941-0.962), suggesting good quantification capability. After 24 h enrichment, all three assays accurately detected 1 to 3 CFU per 25 g of Salmonella among five types of food (cantaloupe, ground beef, ground turkey, shell eggs, and tomato) and three types of feed (cattle feed, chicken feed, and dry dog food) examined. However, 10(1) CFU per 25 g was required for cattle feed when tested by 3M MDA Salmonella. The Salmonella LAMP-BART assay was rapid, specific, sensitive, quantitative, and robust. Upon further validation, it may become a valuable tool for routine screening of Salmonella in various types of food and feed samples.

An immuno-wall microdevice exhibits rapid and sensitive detection of IDH1-R132H mutation specific to grade II and III gliomas

NASA Astrophysics Data System (ADS)

Yamamichi, Akane; Kasama, Toshihiro; Ohka, Fumiharu; Suzuki, Hiromichi; Kato, Akira; Motomura, Kazuya; Hirano, Masaki; Ranjit, Melissa; Chalise, Lushun; Kurimoto, Michihiro; Kondo, Goro; Aoki, Kosuke; Kaji, Noritada; Tokeshi, Manabu; Matsubara, Toshio; Senga, Takeshi; Kaneko, Mika K.; Suzuki, Hidenori; Hara, Masahito; Wakabayashi, Toshihiko; Baba, Yoshinobu; Kato, Yukinari; Natsume, Atsushi

2016-01-01

World Health Organization grade II and III gliomas most frequently occur in the central nervous system (CNS) in adults. Gliomas are not circumscribed; tumor edges are irregular and consist of tumor cells, normal brain tissue, and hyperplastic reactive glial cells. Therefore, the tumors are not fully resectable, resulting in recurrence, malignant progression, and eventual death. Approximately 69-80% of grade II and III gliomas harbor mutations in the isocitrate dehydrogenase 1 gene (IDH1), of which 83-90% are found to be the IDH1-R132H mutation. Detection of the IDH1-R132H mutation should help in the differential diagnosis of grade II and III gliomas from other types of CNS tumors and help determine the boundary between the tumor and normal brain tissue. In this study, we established a highly sensitive antibody-based device, referred to as the immuno-wall, to detect the IDH1-R132H mutation in gliomas. The immuno-wall causes an immunoreaction in microchannels fabricated using a photo-polymerizing polymer. This microdevice enables the analysis of the IDH1 status with a small sample within 15 min with substantially high sensitivity. Our results suggested that 10% content of the IDH1-R132H mutation in a sample of 0.33 μl volume, with 500 ng protein, or from 500 cells is theoretically sufficient for the analysis. The immuno-wall device will enable the rapid and highly sensitive detection of the IDH1-R132H mutation in routine clinical practice.

An immuno-wall microdevice exhibits rapid and sensitive detection of IDH1-R132H mutation specific to grade II and III gliomas.

PubMed

Yamamichi, Akane; Kasama, Toshihiro; Ohka, Fumiharu; Suzuki, Hiromichi; Kato, Akira; Motomura, Kazuya; Hirano, Masaki; Ranjit, Melissa; Chalise, Lushun; Kurimoto, Michihiro; Kondo, Goro; Aoki, Kosuke; Kaji, Noritada; Tokeshi, Manabu; Matsubara, Toshio; Senga, Takeshi; Kaneko, Mika K; Suzuki, Hidenori; Hara, Masahito; Wakabayashi, Toshihiko; Baba, Yoshinobu; Kato, Yukinari; Natsume, Atsushi

2016-01-01

World Health Organization grade II and III gliomas most frequently occur in the central nervous system (CNS) in adults. Gliomas are not circumscribed; tumor edges are irregular and consist of tumor cells, normal brain tissue, and hyperplastic reactive glial cells. Therefore, the tumors are not fully resectable, resulting in recurrence, malignant progression, and eventual death. Approximately 69-80% of grade II and III gliomas harbor mutations in the isocitrate dehydrogenase 1 gene ( IDH1 ), of which 83-90% are found to be the IDH1-R132H mutation. Detection of the IDH1-R132H mutation should help in the differential diagnosis of grade II and III gliomas from other types of CNS tumors and help determine the boundary between the tumor and normal brain tissue. In this study, we established a highly sensitive antibody-based device, referred to as the immuno-wall, to detect the IDH1-R132H mutation in gliomas. The immuno-wall causes an immunoreaction in microchannels fabricated using a photo-polymerizing polymer. This microdevice enables the analysis of the IDH1 status with a small sample within 15 min with substantially high sensitivity. Our results suggested that 10% content of the IDH1-R132H mutation in a sample of 0.33 μl volume, with 500 ng protein, or from 500 cells is theoretically sufficient for the analysis. The immuno-wall device will enable the rapid and highly sensitive detection of the IDH1-R132H mutation in routine clinical practice.

Enhancing Bottom-up and Top-down Proteomic Measurements with Ion Mobility Separations

DOE PAGES

Baker, Erin Shammel; Burnum-Johnson, Kristin E.; Ibrahim, Yehia M.; ...

2015-07-03

Proteomic measurements with greater throughput, sensitivity and additional structural information enhance the in-depth characterization of complex mixtures and targeted studies with additional information and higher confidence. While liquid chromatography separation coupled with mass spectrometry (LC-MS) measurements have provided information on thousands of proteins in different sample types, the additional of another rapid separation stage providing structural information has many benefits for analyses. Technical advances in ion funnels and multiplexing have enabled ion mobility separations to be easily and effectively coupled with LC-MS proteomics to enhance the information content of measurements. Finally, herein, we report on applications illustrating increased sensitivity, throughput,more » and structural information by utilizing IMS-MS and LC-IMS-MS measurements for both bottom-up and top-down proteomics measurements.« less

Rapid tests for the diagnosis of visceral leishmaniasis in patients with suspected disease

PubMed Central

Boelaert, Marleen; Verdonck, Kristien; Menten, Joris; Sunyoto, Temmy; van Griensven, Johan; Chappuis, Francois; Rijal, Suman

2014-01-01

Background The diagnosis of visceral leishmaniasis (VL) in patients with fever and a large spleen relies on showing Leishmania parasites in tissue samples and on serological tests. Parasitological techniques are invasive, require sophisticated laboratories, consume time, or lack accuracy. Recently, rapid diagnostic tests that are easy to perform have become available. Objectives To determine the diagnostic accuracy of rapid tests for diagnosing VL in patients with suspected disease presenting at health services in endemic areas. Search methods We searched MEDLINE, EMBASE, LILACS, CIDG SR, CENTRAL, SCI-expanded, Medion, Arif, CCT, and the WHO trials register on 3 December 2013, without applying language or date limits. Selection criteria This review includes original, phase III, diagnostic accuracy studies of rapid tests in patients clinically suspected to have VL. As reference standards, we accepted: (1) direct smear or culture of spleen aspirate; (2) composite reference standard based on one or more of the following: parasitology, serology, or response to treatment; and (3) latent class analysis. Data collection and analysis Two review authors independently extracted data and assessed quality of included studies using the QUADAS-2 tool. Discrepancies were resolved by a third author. We carried out a meta-analysis to estimate sensitivity and specificity of rapid tests, using a bivariate normal model with a complementary log-log link function. We analysed each index test separately. As possible sources of heterogeneity, we explored: geographical area, commercial brand of index test, type of reference standard, disease prevalence, study size, and risk of bias (QUADAS-2). We also undertook a sensitivity analysis to assess the influence of imperfect reference standards. Main results Twenty-four studies containing information about five index tests (rK39 immunochromatographic test (ICT), KAtex latex agglutination test in urine, FAST agglutination test, rK26 ICT, and rKE16 ICT) recruiting 4271 participants (2605 with VL) were included. We carried out a meta-analysis for the rK39 ICT (including 18 studies; 3622 participants) and the latex agglutination test (six studies; 1374 participants). The results showed considerable heterogeneity. For the rK39 ICT, the overall sensitivity was 91.9% (95% confidence interval (95% CI) 84.8 to 96.5) and the specificity 92.4% (95% CI 85.6 to 96.8). The sensitivity was lower in East Africa (85.3%; 95% CI 74.5 to 93.2) than in the Indian subcontinent (97.0%; 95% CI 90.0 to 99.5). For the latex agglutination test, overall sensitivity was 63.6% (95% CI 40.9 to 85.6) and specificity 92.9% (95% CI 76.7 to 99.2). Authors' conclusions The rK39 ICT shows high sensitivity and specificity for the diagnosis of visceral leishmaniasis in patients with febrile splenomegaly and no previous history of the disease, but the sensitivity is notably lower in east Africa than in the Indian subcontinent. Other rapid tests lack accuracy, validation, or both. PLAIN LANGUAGE SUMMARY Rapid diagnostic tests for visceral leishmaniasis Visceral leishmaniasis (or kala-azar) is caused by a parasite, results in fever, a large spleen and other health problems, occuring in India, Bangladesh and Nepal, east Africa, the Mediterranean region and Brazil. Without treatment people die, and proper treatment can result in cure, so diagnosis is important. Many of the tests that are used to determine if a person has visceral leishmaniasis are complicated, costly, painful and sometimes dangerous for the patients. Now rapid diagnostic tests that are safe and easy to perform are available. This Cochrane review describes how accurate these rapid diagnostic tests are for diagnosing visceral leishmaniasis. We summarize those studies that evaluated the rapid tests in people who, according to their physicians, could have the disease. We only included studies in which the researchers had used established methods to distinguish the people with visceral leishmaniasis from those who did not have the disease. We found 24 studies, which contained information about five different rapid tests. A total of 4271 people participated in these studies. One of the rapid tests (called the rK39 immunochromatographic test) gave correct, positive results in 92% of the people with visceral leishmaniasis and it gave correct, negative results in 92% of the people who did not have the disease. This test worked better in India and Nepal than in east Africa. In India and Nepal, it gave correct, positive results in 97% of the people with the disease. In east Africa, it gave correct, positive results in only 85% of the people with the disease. A second rapid test (called latex agglutination test) gave correct, positive results in 64% of the people with the disease and it gave correct, negative results in 93% of the people without the disease. For the other rapid tests evaluated, there are too few studies to know how accurate they are. PMID:24947503

Development and Evaluation of a Rapid and Sensitive EBOV-RPA Test for Rapid Diagnosis of Ebola Virus Disease.

PubMed

Yang, Mingjuan; Ke, Yuehua; Wang, Xuesong; Ren, Hang; Liu, Wei; Lu, Huijun; Zhang, Wenyi; Liu, Shiwei; Chang, Guohui; Tian, Shuguang; Wang, Lihua; Huang, Liuyu; Liu, Chao; Yang, Ruifu; Chen, Zeliang

2016-06-01

Confirming Ebola virus disease (EVD), a deadly infectious disease, requires real-time RT-PCR, which takes up to a few hours to yield results. Therefore, a rapid diagnostic assay is imperative for EVD diagnosis. A rapid nucleic acid test based on recombinase polymerase amplification (EBOV-RPA) was developed to specifically detect the 2014 outbreak strains. The EBOV-RPA assay was evaluated by testing samples from suspected EVD patients in parallel with RT-PCR. An EBOV-RPA, which could be completed in 20 min, was successfully developed. Of 271 patients who tested positive for Ebola virus by RT-PCR, 264 (sensitivity: 97%, 95% CI: 95.5-99.3%) were positive by EBOV-RPA; 101 of 104 patients (specificity: 97%, 95% CI: 93.9-100%) who tested negative by RT-PCR were also negative by EBOV-RPA. The sensitivity values for samples with a Ct value of <34, which accounted for 95.59% of the samples, was 100%. Discordant samples positive by RT-PCR but negative by EBOV-RPA had significantly high Ct values. Results of external quality assessment samples with EBOV-RPA were 100%, consistent with those of RT-PCR. The EBOV-RPA assay showed 97% sensitivity and 97% specificity for all EVD samples tested, making it a rapid and sensitive test for EVD diagnosis.

[Early diagnosis of streptococcal pharyngitis in paediatric practice: Validity of a rapid antigen detection test].

PubMed

Flores Mateo, Gemma; Conejero, Jaume; Grenzner Martinel, Elisabet; Baba, Zeki; Dicono, Susana; Echasabal, Mildrey; Gonzalo Santos, Concepción; Aliaga, Arantxa; Barredo, María; Ruiz, Luis; Carrau, Montserrat

2010-07-01

To determine the validity of the rapid antigen test for the diagnoses of acute pharyngitis caused by group A beta-haemolytic Streptococcus (GABHS) compared with culture. Observational study of a consecutive sample of paediatric patients. Two primary care centres (PCC) from the metropolitan area of Barcelona. Children aged 1-14 years with sore throat of no more than 5 days duration were chosen at PCC. Oropharyngeal samples were collected from tonsillar bed and posterior pharynx. A rapid diagnostic test was performed, as well as a throat culture. A total of 211 patients were studied. The overall prevalence of pharyngitis due to Streptococcus was 34.1%. Compared with the throat culture, the sensitivity of the rapid test was 90.3% (95% CI: 81.0-96.0), the specificity was 78.4% (95% CI: 70.6-84.9). The percentage of false negatives was 9.7% and the false positives was 21.6%. Spectrum bias was present, inasmuch as the rapid test sensitivity increased with Centor scores. The diagnostic value of a rapid antigen test for the diagnosis of streptococcal pharyngitis in paediatric patients at PCC is high. However, the percentage of false positives and negatives is too high, and also the sensitivity is too low in patients with fewer symptoms to support the use of rapid antigenic test without culture confirmation and bacterial sensitivity test. 2009 Elsevier España, S.L. All rights reserved.

Development and clinical evaluation of a rapid diagnostic kit for feline leukemia virus infection.

PubMed

Kim, Won-Shik; Chong, Chom-Kyu; Kim, Hak-Yong; Lee, Gyu-Cheol; Jeong, Wooseog; An, Dong-Jun; Jeoung, Hye-Young; Lee, Jae-In; Lee, Young-Ki

2014-01-01

Feline leukemia virus (FeLV) causes a range of neoplastic and degenerative diseases in cats. To obtain a more sensitive and convenient diagnosis of the disease, we prepared monoclonal antibodies specific for the FeLV p27 to develop a rapid diagnostic test with enhanced sensitivity and specificity. Among these antibodies, we identified two clones (hybridomas 8F8B5 and 8G7D1) that specifically bound to FeLV and were very suitable for a diagnostic kit. The affinity constants for 8F8B5 and 8G7D1 were 0.35 × 10⁸ and 0.86 × 10⁸, respectively. To investigate the diagnostic abilities of the rapid kit using these antibodies, we performed several clinical studies. Assessment of analytical sensitivity revealed that the detection threshold of the rapid diagnostic test was 2 ng/mL for recombinant p27 and 12.5 × 10⁴ IU/mL for FeLV. When evaluating 252 cat sera samples, the kit was found to have a kappa value of 0.88 compared to polymerase chain reaction (PCR), indicating a significant correlation between data from the rapid diagnostic test and PCR. Sensitivity and specificity of the kit were 95.2% (20/21) and 98.5% (257/261), respectively. Our results demonstrated that the rapid diagnostic test would be a suitable diagnostic tool for the rapid detection of FeLV infection in cats.

Perfusion MR imaging detection of carcinoma arising from preexisting salivary gland pleomorphic adenoma by computer-assisted analysis of time-signal intensity maps

PubMed Central

Katayama, Ikuo; Eida, Sato; Fujita, Shuichi; Hotokezaka, Yuka; Sumi, Misa

2017-01-01

Tumor perfusion can be evaluated by analyzing the time-signal intensity curve (TIC) after dynamic contrast-enhanced (DCE) MR imaging. Accordingly, TIC profiles are characteristic of some benign and malignant salivary gland tumors. A carcinoma ex pleomorphic adenoma (CXPA) arises from a long-standing pleomorphic adenoma (PA) and has a distinctive prognostic risk depending on the tumor growth potential such as invasion beyond the preexisting capsule. Differentiating CXPA from PA can be very challenging. In this study, we have attempted to discriminate CXPA from PA based on a two-dimensional TIC mapping algorithm. TIC mapping analysis was performed on 8 patients with CXPA and 20 patients with PA after dynamic contrast-enhanced (DCE) MR imaging using a 1.5-T MR system. The TIC profiles obtained were automatically categorized into 5 types based on the enhancement ratio, maximum time, and washout ratio (Type 1 TIC with flat profile, Type 2 TIC with slow uptake, Type 3 TIC with rapid uptake and a low washout ratio, Type 4 TIC with rapid uptake and a high washout ratio, and Type 5 TIC not otherwise specific). The percentage tumor areas with each of the 5 TIC types were compared between CXPAs and PAs. Stepwise differentiation and cluster analysis using multiple TIC cut-off thresholds distinguished CXPAs from PAs with 75% sensitivity, 95% specificity, 86% accuracy, and 86% positive and 90% negative predictive values, when tumors with ≤1.1% Type 1 and ≥15% Type 4, or those with ≤1.1% Type 1, ≥78.1% Type 2, ≥16.1% Type 3, and <15% Type 4, or those with >1.1% Type 1, ≥78.1% Type 2, and ≥16.1% Type 3 areas were diagnosed as CXPAs. The overall TIC profiles predicted some aggressive CXPA growth patterns. These results suggest that stepwise differentiation based on TIC mapping is helpful in differentiating CXPAs from PAs. PMID:28531213

A Method for Rapid Measurement of Contrast Sensitivity on Mobile Touch-Screens

NASA Technical Reports Server (NTRS)

Mulligan, Jeffrey B.

2016-01-01

Touch-screen displays in cell phones and tablet computers are now pervasive, making them an attractive option for vision testing outside of the laboratory or clinic. Here we de- scribe a novel method in which subjects use a finger swipe to indicate the transition from visible to invisible on a grating which is swept in both contrast and frequency. Because a single image can be swiped in about a second, it is practical to use a series of images to zoom in on particular ranges of contrast or frequency, both to increase the accuracy of the measurements and to obtain an estimate of the reliability of the subject. Sensitivities to chromatic and spatio-temporal modulations are easily measured using the same method. A proto- type has been developed for Apple Computer's iPad/iPod/iPhone family of devices, implemented using an open-source scripting environment known as QuIP (QUick Image Processing, http://hsi.arc.nasa.gov/groups/scanpath/research.php). Preliminary data show good agreement with estimates obtained from traditional psychophysical methods as well as newer rapid estimation techniques. Issues relating to device calibration are also discussed.

Sensitivity and specificity for detecting basal cell carcinomas in Mohs excisions with confocal fluorescence mosaicing microscopy

NASA Astrophysics Data System (ADS)

Gareau, Daniel S.; Karen, Julie K.; Dusza, Stephen W.; Tudisco, Marie; Nehal, Kishwer S.; Rajadhyaksha, Milind

2009-05-01

Recent studies have demonstrated the ability of confocal fluorescence mosaicing microscopy to rapidly detect basal cell carcinomas (BCCs) directly in thick and fresh Mohs surgical excisions. Mosaics of confocal images display large areas of tissue with high resolution and magnification equivalent to 2×, which is the standard magnification when examining pathology. Comparison of mosaics to Mohs frozen histopathology was shown to be excellent for all types of BCCs. However, comparisons in the previous studies were visual and qualitative. In this work, we report the results of a semiquantitative preclinical study in which 45 confocal mosaics are blindly evaluated for the presence (or absence) of BCC tumor. The evaluations are made by two clinicians: a senior Mohs surgeon with prior expertise in interpreting confocal images, and a novice Mohs fellow with limited experience. The blinded evaluation is compared to the gold standard of frozen histopathology. BCCs are detected with an overall sensitivity of 96.6%, specificity of 89.2%, positive predictive value of 93.0%, and negative predictive value of 94.7%. The results demonstrate the potential clinical utility of confocal mosaicing microscopy toward rapid surgical pathology at the bedside to expedite and guide surgery.

Amyloid-specific fluorophores for the rapid, sensitive in situ detection of prion contamination on surgical instruments.

PubMed

Lipscomb, I P; Hervé, R; Harris, K; Pinchin, H; Collin, R; Keevil, C W

2007-09-01

Prion diseases or transmissible spongiform encephalopathies (TSEs) are a group of rare, transmissible and fatal neurodegenerative diseases associated with the protein agent (PrP(Sc)). As such, the sensitive and rapid detection of prion PrP(Sc) amyloid on the surface of suspect surgical instruments is of great importance and may even allow remedial action to be taken prior to any further operative intervention and possible iatrogenic transmission. However, conventional PrP(Sc) detection methodologies tend to rely on the inefficient and unreliable removal of suspect material from a surface using swabs or wipes prior to antibody analysis. Here we show how the combination of an advanced light microscope technique, episcopic differential interference contrast/epifluorescence (EDIC/EF) microscopy, and the application of beta-amyloid fluorescent thiazole markers (thioflavin T, thioflavin S) can be used to detect, in situ, submicron (attomole) levels of prion protein amyloid contamination in brain and spleen sections, smears and homogenate on surgical stainless steel surfaces and surgical instruments. This technique, although not specific to an amyloid type, can be used to verify that surgical instruments are substantially free from prion amyloid protein soiling and hence reduce the risk of iatrogenic transmission.

Rapid and specific detection of porcine parvovirus by isothermal recombinase polymerase amplification assays.

PubMed

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

2016-10-01

Porcine parvovirus (PPV) is a major cause of swine reproductive failure and reported in many countries worldwide. Recombinase polymerase amplification (RPA) assays using a real-time fluorescent detection (PPV real-time RPA assay) and a lateral flow dipstick (PPV RPA LFD assay) were developed targeting PPV NS1 gene. The detection limit of PPV real-time RPA assay was 300 copies per reaction within 9 min at 38 °C, while the RPA LFD assay has a detection limit of 400 copies per reaction in less than 20 min at 38 °C. In both assays, there were no cross-reactions with porcine circovirus type 2, pseudorabies virus, porcine reproductive and respiratory syndrome virus, classical swine fever virus, and foot-and-mouth disease virus. Based on a total of 128 clinical samples examined, the sensitivity and the specificity of the developed RPA assays for identification of PPV was 94.4% and 100%, respectively, when compared to real-time (qPCR) assay. Therefore, the RPA assay provides a rapid, sensitive and specific alternative for PPV detection. Copyright © 2016 Elsevier Ltd. All rights reserved.

Advances in biological dosimetry

NASA Astrophysics Data System (ADS)

Ivashkevich, A.; Ohnesorg, T.; Sparbier, C. E.; Elsaleh, H.

2017-01-01

Rapid retrospective biodosimetry methods are essential for the fast triage of persons occupationally or accidentally exposed to ionizing radiation. Identification and detection of a radiation specific molecular ‘footprint’ should provide a sensitive and reliable measurement of radiation exposure. Here we discuss conventional (cytogenetic) methods of detection and assessment of radiation exposure in comparison to emerging approaches such as gene expression signatures and DNA damage markers. Furthermore, we provide an overview of technical and logistic details such as type of sample required, time for sample preparation and analysis, ease of use and potential for a high throughput analysis.

Combining isothermal rolling circle amplification and electrochemiluminescence for highly sensitive point mutation detection

NASA Astrophysics Data System (ADS)

Su, Qiang; Zhou, Xiaoming

2008-12-01

Many pathogenic and genetic diseases are associated with changes in the sequence of particular genes. We describe here a rapid and highly efficient assay for the detection of point mutation. This method is a combination of isothermal rolling circle amplification (RCA) and high sensitive electrochemluminescence (ECL) detection. In the design, a circular template generated by ligation upon the recognition of a point mutation on DNA targets was amplified isothermally by the Phi29 polymerase using a biotinylated primer. The elongation products were hybridized with tris (bipyridine) ruthenium (TBR)-tagged probes and detected in a magnetic bead based ECL platform, indicating the mutation occurrence. P53 was chosen as a model for the identification of this method. The method allowed sensitive determination of the P53 mutation from wild-type and mutant samples. The main advantage of RCA-ECL is that it can be performed under isothermal conditions and avoids the generation of false-positive results. Furthermore, ECL provides a faster, more sensitive, and economical option to currently available electrophoresis-based methods.

Interleukin-4-dependent innate collaboration between iNKT cells and B-1 B cells controls adaptative contact sensitivity

PubMed Central

Campos, Regis A; Szczepanik, Marian; Itakura, Atsuko; Lisbonne, Mariette; Dey, Neelendu; Leite-de-Moraes, Maria C; Askenase, Philip W

2006-01-01

We showed that hepatic Vα14+ invariant natural killer T (iNKT) cells, via their rapid interleukin (IL)-4 production, activate B-1 cells to initiate contact sensitivity (CS). This innate collaboration was absent in IL-4–/– and signal transducer and activator of transcription (STAT)-6–/– mice and was inhibited by anti-IL-4 treatment. These mice have defective CS because they fail to locally recruit the sensitized effector T cells of acquired immunity. Their CS is reconstituted by transfer of downstream-acting 1-day immune B-1 cells from wild-type mice. Responses were not reconstituted with B-1 cells from IL-4 receptor-α–/– or STAT-6–/– mice, nor by IL-4 treatment of B cell-deficient mice at immunization. Finally, IL-4 was preferentially and transiently produced by hepatic iNKT cells within 7 min after sensitization to mediate collaboration between innate-like iNKT cells and the B-1 B cells that participate in the recruitment of effector T cells in vivo. PMID:16556268

Engineering 'cell robots' for parallel and highly sensitive screening of biomolecules under in vivo conditions.

PubMed

Song, Lifu; Zeng, An-Ping

2017-11-09

Cells are capable of rapid replication and performing tasks adaptively and ultra-sensitively and can be considered as cheap "biological-robots". Here we propose to engineer cells for screening biomolecules in parallel and with high sensitivity. Specifically, we place the biomolecule variants (library) on the bacterial phage M13. We then design cells to screen the library based on cell-phage interactions mediated by a specific intracellular signal change caused by the biomolecule of interest. For proof of concept, we used intracellular lysine concentration in E. coli as a signal to successfully screen variants of functional aspartate kinase III (AK-III) under in vivo conditions, a key enzyme in L-lysine biosynthesis which is strictly inhibited by L-lysine. Comparative studies with flow cytometry method failed to distinguish the wild-type from lysine resistance variants of AK-III, confirming a higher sensitivity of the method. It opens up a new and effective way of in vivo high-throughput screening for functional molecules and can be easily implemented at low costs.

Rapid Magnetic Nanobiosensor for the detection of Serratia marcescen

NASA Astrophysics Data System (ADS)

Aljabali, Alaa A. A.; Hussein, Emad; Aljumaili, Omar; Zoubi, Mazhar Al; Altrad, Bahaa; Albatayneh, Khaled; Al-razaq, Mutaz A. Abd

2018-02-01

The development of rapid, sensitive, accurate and reliable bacterial detection methods are of keen interest to ensure food safety and hospital security. Therefore, the development of a fast, specific, low-cost and trusted methods is in high demand. Magnetic nanoparticles with their unique material properties have been utilized as a tool for pathogen detection. Here, we present a novel iron oxide nanoparticles labeled with specific targeting antibodies to improve specificity and extend the use of nanoparticles as nanosensors. The results indicated that antibody labeled iron oxide platform that binds specifically to Serriata marcescenst in a straightforward method is very specific and sensitive. The system is capable of rapid and specific detection of various clinically relevant bacterial species, with sensitivity down to single bacteria. The generic platform could be used to identify pathogens for a variety of applications rapidly.

RAPID PCR-BASED MONITORING OF INFECTIOUS ENTEROVIRUSES IN DRINKING WATER. (R824756)

EPA Science Inventory

Abstract

Currently, the standard method for the detection of enteroviruses and hepatitis A virus in water involves cell culture assay which is expensive and time consuming. Direct RT-PCR offers a rapid and sensitive alternative to virus detection but sensitivity is oft...

APPEARANCE OF NEW PHAGE TYPES AND NEW LYSOGENIC STRAINS AFTER ADAPTATION OF LYSOGENIC B. MEGATHERIUM TO AMMONIUM SULFATE CULTURE MEDIUM

PubMed Central

Northrop, John H.; Murphy, James S.

1956-01-01

1. Lysogenic B. megatherium 899a was adapted to growth in a minimal ammonium sulfate medium (ASCM). 2. Adaptation took place slowly and the following changes in the culture occurred: (a) The growth rate increased from 0.5 to 1.5–2.0/hr. (b) The culture changed from diffuse to mucoid. (c) The total phage titer, and the gelatinase concentration decreased to 1/100 or less. (d) The types of phage produced changed from >99 per cent T (wild type) to 30 to 60 per cent miscellaneous clear types. The original T phage was replaced by a different smaller t, never observed in the original 899a culture. (e) Several new colony types also appeared, but the colony morphology was not correlated with the phage types produced. None of the colony types was stable on repeated transfer either in peptone or ASCM, but continued to disassociate into different colony types (cf. Ivánovics, 1955). 3. Control experiments showed that these changes in phage production and colony types could not be brought about by growing sensitive B. megatherium in the presence of the various new phages, in ASCM. It is therefore unlikely that the changes observed in adapted culture were due to infection of a sensitive cell with phage. 4. Continued growth of the ASCM-adapted strain in peptone resulted in increasing the total phage titer, and also the gelatinase concentration. The growth rate returned to its original value and the ability to grow rapidly in ASCM was soon lost. The phage types, however, remained the same as in the ASCM. 5. An improved cell for steady state growth is described. PMID:13295557

Novel strategy for typing Mycoplasma pneumoniae isolates by use of matrix-assisted laser desorption ionization-time of flight mass spectrometry coupled with ClinProTools.

PubMed

Xiao, Di; Zhao, Fei; Zhang, Huifang; Meng, Fanliang; Zhang, Jianzhong

2014-08-01

The typing of Mycoplasma pneumoniae mainly relies on the detection of nucleic acid, which is limited by the use of a single gene target, complex operation procedures, and a lengthy assay time. Here, matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) coupled to ClinProTools was used to discover MALDI-TOF MS biomarker peaks and to generate a classification model based on a genetic algorithm (GA) to differentiate between type 1 and type 2 M. pneumoniae isolates. Twenty-five M. pneumoniae strains were used to construct an analysis model, and 43 Mycoplasma strains were used for validation. For the GA typing model, the cross-validation values, which reflect the ability of the model to handle variability among the test spectra and the recognition capability value, which reflects the model's ability to correctly identify its component spectra, were all 100%. This model contained 7 biomarker peaks (m/z 3,318.8, 3,215.0, 5,091.8, 5,766.8, 6,337.1, 6,431.1, and 6,979.9) used to correctly identify 31 type 1 and 7 type 2 M. pneumoniae isolates from 43 Mycoplasma strains with a sensitivity and specificity of 100%. The strain distribution map and principle component analysis based on the GA classification model also clearly showed that the type 1 and type 2 M. pneumoniae isolates can be divided into two categories based on their peptide mass fingerprints. With the obvious advantages of being rapid, highly accurate, and highly sensitive and having a low cost and high throughput, MALDI-TOF MS ClinProTools is a powerful and reliable tool for M. pneumoniae typing. Copyright © 2014, American Society for Microbiology. All Rights Reserved.

Application of PCR to a clinical and environmental investigation of a case of equine botulism.

PubMed

Szabo, E A; Pemberton, J M; Gibson, A M; Thomas, R J; Pascoe, R R; Desmarchelier, P M

1994-08-01

PCR for the detection of botulinum neurotoxin gene types A to E was used in the investigation of a case of equine botulism. Samples from a foal diagnosed with toxicoinfectious botulism in 1985 were reanalyzed by PCR and the mouse bioassay in conjunction with an environmental survey. Neurotoxin B was detected by mouse bioassay in culture enrichments of serum, spleen, feces, and intestinal contents. PCR results compared well with mouse bioassay results, detecting type B neurotoxin genes in these samples and also in a liver sample. Other neurotoxin types were not detected by either test. Clostridium botulinum type B was shown to be prevalent in soils collected from the area in which the foal was raised. Four methods were used to test for the presence of botulinum neurotoxin-producing organisms in 66 soil samples taken within a 5-km radius: PCR and agarose gel electrophoresis (types A to E), PCR and an enzyme-linked assay (type B), hybridization of crude alkaline cell lysates with a type B-specific probe, and the mouse bioassay (all types). Fewer soil samples were positive for C. botulinum type B by the mouse bioassay (15%) than by any of the DNA-based detection systems. Hybridization of a type B-specific probe to DNA dot blots (26% of the samples were positive) and PCR-enzyme-linked assay (77% of the samples were positive) were used for the rapid analysis of large numbers of samples, with sensitivity limits of 3 x 10(6) and 3,000 cells, respectively. Conventional detection of PCR products by gel electrophoresis was the most sensitive method (300-cell limit), and in the present environmental survey, neurotoxin B genes only were detected in 94% of the samples.

Application of PCR to a clinical and environmental investigation of a case of equine botulism.

PubMed Central

Szabo, E A; Pemberton, J M; Gibson, A M; Thomas, R J; Pascoe, R R; Desmarchelier, P M

1994-01-01

PCR for the detection of botulinum neurotoxin gene types A to E was used in the investigation of a case of equine botulism. Samples from a foal diagnosed with toxicoinfectious botulism in 1985 were reanalyzed by PCR and the mouse bioassay in conjunction with an environmental survey. Neurotoxin B was detected by mouse bioassay in culture enrichments of serum, spleen, feces, and intestinal contents. PCR results compared well with mouse bioassay results, detecting type B neurotoxin genes in these samples and also in a liver sample. Other neurotoxin types were not detected by either test. Clostridium botulinum type B was shown to be prevalent in soils collected from the area in which the foal was raised. Four methods were used to test for the presence of botulinum neurotoxin-producing organisms in 66 soil samples taken within a 5-km radius: PCR and agarose gel electrophoresis (types A to E), PCR and an enzyme-linked assay (type B), hybridization of crude alkaline cell lysates with a type B-specific probe, and the mouse bioassay (all types). Fewer soil samples were positive for C. botulinum type B by the mouse bioassay (15%) than by any of the DNA-based detection systems. Hybridization of a type B-specific probe to DNA dot blots (26% of the samples were positive) and PCR-enzyme-linked assay (77% of the samples were positive) were used for the rapid analysis of large numbers of samples, with sensitivity limits of 3 x 10(6) and 3,000 cells, respectively. Conventional detection of PCR products by gel electrophoresis was the most sensitive method (300-cell limit), and in the present environmental survey, neurotoxin B genes only were detected in 94% of the samples. Images PMID:7989554

Direct immunofluorescence assay compared to cell culture for the diagnosis of mucocutaneous herpes simplex virus infections in children.

PubMed

Caviness, A Chantal; Oelze, Lindsay L; Saz, Ulas E; Greer, Jewel M; Demmler-Harrison, Gail J

2010-09-01

Direct immunofluorescence assay (DFA) is commonly used for the rapid identification of herpes simplex virus (HSV) infection in mucocutaneous lesions, yet little is known about its diagnostic accuracy. To determine the diagnostic yield and accuracy of HSV DFA for the diagnosis of mucocutaneous HSV infection in pediatric patients. Retrospective cross-sectional study of all patients who underwent HSV DFA testing by the Texas Children's Hospital Diagnostic Virology between January 1, 1995 and December 31, 2005. HSV DFA sensitivity, specificity, positive likelihood ratio (LRs), and negative LRs were estimated using viral culture as the reference standard. 659 specimens were submitted for HSV DFA with concurrent viral cultures. Viral cultures were positive for HSV type 1 in 158 (24%) and HSV type 2 in 2 (0.3%). There were 433 different patients with a median age of 8.6 years. Types of lesions were as follows: 50% ulcerative, 26% vesicular, 8% erythema or purpura, 5% pustular, and 11% missing. Of the 659 specimens submitted for HSV DFA, 160 (24%) were inconclusive due to inadequate cells. Of the 499 adequate specimens, overall HSV DFA test accuracy was: sensitivity 61%, specificity 99%, LR positive 40, and LR negative 0.39. A quarter of specimens submitted for HSV DFA testing are not adequate for DFA testing. When HSV DFA can be performed, it is specific, but not sensitive, for the identification of mucocutaneous HSV infection in children. Copyright (c) 2010 Elsevier B.V. All rights reserved.

Serine Protease Zymography: Low-Cost, Rapid, and Highly Sensitive RAMA Casein Zymography.

PubMed

Yasumitsu, Hidetaro

2017-01-01

To detect serine protease activity by zymography, casein and CBB stain have been used as a substrate and a detection procedure, respectively. Casein zymography has been using substrate concentration at 1 mg/mL and employing conventional CBB stain. Although ordinary casein zymography provides reproducible results, it has several disadvantages including time-consuming and relative low sensitivity. Improved casein zymography, RAMA casein zymography, is rapid and highly sensitive. RAMA casein zymography completes the detection process within 1 h after incubation and increases the sensitivity at least by tenfold. In addition to serine protease, the method also detects metalloprotease 7 (MMP7, Matrilysin) with high sensitivity.

Cloning the promoter for transforming growth factor-beta type III receptor. Basal and conditional expression in fetal rat osteoblasts

NASA Technical Reports Server (NTRS)

Ji, C.; Chen, Y.; McCarthy, T. L.; Centrella, M.

1999-01-01

Transforming growth factor-beta binds to three high affinity cell surface molecules that directly or indirectly regulate its biological effects. The type III receptor (TRIII) is a proteoglycan that lacks significant intracellular signaling or enzymatic motifs but may facilitate transforming growth factor-beta binding to other receptors, stabilize multimeric receptor complexes, or segregate growth factor from activating receptors. Because various agents or events that regulate osteoblast function rapidly modulate TRIII expression, we cloned the 5' region of the rat TRIII gene to assess possible control elements. DNA fragments from this region directed high reporter gene expression in osteoblasts. Sequencing showed no consensus TATA or CCAAT boxes, whereas several nuclear factors binding sequences within the 3' region of the promoter co-mapped with multiple transcription initiation sites, DNase I footprints, gel mobility shift analysis, or loss of activity by deletion or mutation. An upstream enhancer was evident 5' proximal to nucleotide -979, and a silencer region occurred between nucleotides -2014 and -2194. Glucocorticoid sensitivity mapped between nucleotides -687 and -253, whereas bone morphogenetic protein 2 sensitivity co-mapped within the silencer region. Thus, the TRIII promoter contains cooperative basal elements and dispersed growth factor- and hormone-sensitive regulatory regions that can control TRIII expression by osteoblasts.

A novel, highly sensitive, selective, reversible and turn-on chemi-sensor based on Schiff base for rapid detection of Cu(II)

NASA Astrophysics Data System (ADS)

Saleh, Sayed M.; Ali, Reham; Ali, Ibrahim A. I.

2017-08-01

In this work, a novel optical fluoro-chemisensor was designed and synthesized for copper (II) ions detection. The sensor film is created by embedded N,N-Bis(2-hydroxo-5-bromobenzyl)ethylenediamine in poly vinyl chloride (PVC) film in presence of dioctyl phthalate (DOP) as plasticizer. The receptor Schiff base reveals "off-on" mode with high selectivity, significant sensitivity to Cu(II) ions. The selectivity of optical sensor for Cu(II) ions is the result of chelation enhanced fluorescence (CHEF). The optimal conditions of pH and response time at which higher efficiency of sensor film is performed was found to be 6.8 and 2.48 min. The possible interference of other metal ions in solution was examined in presence of different types of metal ions. This film shows high selectivity and ultra-sensitivity with low detection limit LOD (1.1 × 10- 8 M). Thus, these considerable properties make it viable to monitor copper metal ions within very low concentration range (0-15 × 10- 6 M Cu(II)) and highly selective even in the presence of different types of metal ions. The sensor reversibility was achieved by utilizing EDTA solution with concentration of 0.1 M solution.

Diagnosis of Normal and Abnormal Color Vision with Cone-Specific VEPs.

PubMed

Rabin, Jeff C; Kryder, Andrew C; Lam, Dan

2016-05-01

Normal color vision depends on normal long wavelength (L), middle wavelength (M), and short wavelength sensitive (S) cones. Hereditary "red-green" color vision deficiency (CVD) is due to a shift in peak sensitivity or lack of L or M cones. Hereditary S cone CVD is rare but can be acquired as an early sign of disease. Current tests detect CVD but few diagnose type or severity, critical for linking performance to real-world demands. The anomaloscope and newer subjective tests quantify CVD but are not applicable to infants or cognitively impaired patients. Our purpose was to develop an objective test of CVD with sensitivity and specificity comparable to current tests. A calibrated visual-evoked potential (VEP) display and Food and Drug Administration-approved system was used to record L, M, and S cone-specific pattern-onset VEPs from 18 color vision normals (CVNs) and 13 hereditary CVDs. VEP amplitudes and latencies were compared between groups to establish VEP sensitivity and specificity. Cone VEPs show 100% sensitivity for diagnosis of CVD and 94% specificity for confirming CVN. L cone (protan) CVDs showed a significant increase in L cone latency (53.1 msec, P < 0.003) and decreased amplitude (10.8 uV, P < 0.0000005) but normal M and S cone VEPs ( P > 0.31). M cone (deutan) CVDs showed a significant increase in M cone latency (31.0 msec, P < 0.000004) and decreased amplitude (8.4 uV, P < 0.006) but normal L and S cone VEPs ( P > 0.29). Cone-specific VEPs offer a rapid, objective test to diagnose hereditary CVD and show potential for detecting acquired CVD in various diseases. This paper describes the efficacy of cone-specific color VEPs for quantification of normal and abnormal color vision. The rapid, objective nature of this approach makes it suitable for detecting color sensitivity loss in infants and the cognitively impaired.

Rapid and Accurate Diagnosis of Acute Pyogenic Meningitis Due to Streptococcus Pneumoniae, Haemophilus influenzae Type b and Neisseria meningitidis Using A Multiplex PCR Assay.

PubMed

Seth, Rajeev; Murthy, Peela Sree Ramchandra; Sistla, Sujatha; Subramanian, Mahadevan; Tamilarasu, Kadhiravan

2017-09-01

Acute bacterial meningitis is one of the major causes of morbidity and mortality in children and geriatric population, especially in developing countries. Methods of identification are standard culture and other phenotypic tests in many resource poor settings. To use molecular methods for the improvement of aetiological diagnosis of acute pyogenic meningitis in patients. CSF samples of 125 patients were included for the study. Gram staining and culture were performed according to standard procedures. Antigen was detected using commercial latex agglutination test kit. Multiplex PCR was performed using previously published primers and protocols. Fischer's exact test was used for finding association between presence of the disease and clinical/biochemical parameters, considering two tailed p<0.05 as statistically significant. Sensitivity, specificity, positive and negative predictive values were calculated using Graphpad QuicCalc software. A total of 39 cases (31.2%) were confirmed to be of acute pyogenic meningitis based on biochemical methods. Only 10/39 was positive for the three organisms tested. Multiplex PCR was able to detect one additional isolate each of Streptococcus pneumoniae and Haemophilus influenzae type b. When compared with multiplex PCR as the gold standard, culture and latex agglutination tests had same sensitivity (80%), specificity (100%), PPV (100%) and NPV (97.8%), whereas Gram stain had poor sensitivity (40%) and good specificity (95.6%). Detection rates were higher in multiplex PCR for the two organisms Streptococcus pneumoniae and Haemophilus influenzae type b. Multiplex PCR was more sensitive than culture or antigen detection, and employing this assay can significantly increase the speed and accuracy of identification of the pathogen.

Comparison of two commercial carbapenemase gene confirmatory assays in multiresistant Enterobacteriaceae and Acinetobacter baumannii-complex.

PubMed

Rösner, Stephan; Gehlweiler, Kevin; Küsters, Uta; Kolbert, Mathias; Hübner, Kirsten; Pfennigwerth, Niels; Mack, Dietrich

2018-01-01

Multidrug-resistant Gram-negative bacilli (MDR-GNB) producing carbapenemases are increasing at an alarming speed. Rapid confirmation of carbapenemase type will be an important diagnostic step in clinical microbiology laboratories not only to reduce the risk of transmissions but also for optimising antibiotic therapy in the future. We compared diagnostic reliability of two commercially available molecular assays (Check-Direct CPE vs. AID line probe assay) for detection and typing of carbapenemase genes in 80 well-characterized isolates of MDR-GNB. Respective strains were isolated in various clinical specimens at our clinical microbiology laboratory. The reference standard included confirmation of carbapenemase-production at the molecular level at the German National Reference Laboratory for Multidrug-resistant Gram-negative bacteria (Ruhr-University Bochum, Germany). 53 Enterobacteriaceae and 27 members of the A. baumannii-complex were used in this study. The tested assays appeared highly reliable to confirm carbapenemase-producing Enterobacteriaceae (CPE) with respective sensitivities of 97.7%, but are currently unsuitable for analysis of members of the A. baumannii-complex. Both assays are easy to perform and rapid tools for confirmation and typing of the most common carbapenemase genes in Enterobacteriaceae. Implementation should be possible for any clinical microbiology laboratory with Check-Direct CPE being easier to handle and having less technological requirements.

Development of single-step multiplex real-time RT-PCR assays for rapid diagnosis of enterovirus 71, coxsackievirus A6, and A16 in patients with hand, foot, and mouth disease.

PubMed

Puenpa, Jiratchaya; Suwannakarn, Kamol; Chansaenroj, Jira; Vongpunsawad, Sompong; Poovorawan, Yong

2017-10-01

Real-time reverse-transcription polymerase chain reaction (rRT-PCR) to detect enterovirus 71 (EV-A71) and coxsackievirus A16 (CV-A16) has facilitated the rapid and accurate identification of the two most common etiological agents underlying hand, foot, and mouth disease (HFMD). However, the worldwide emergence of CV-A6 infection in HFMD necessitates development of an improved multiplex rRT-PCR method. To rapidly determine the etiology of HFMD, two rRT-PCR assays using TaqMan probes were developed to differentiate among three selected common enteroviruses (EV-A71, CV-A16 and CV-A6) and to enable broad detection of enteroviruses (pan-enterovirus assay). No cross-reactions were observed with other RNA viruses examined. The detection limits of both assays were 10 copies per microliter for EV-A71, CV-A6 and CV-A16, and pan-enterovirus. The methods showed high accuracy (EV-A71, 90.6%; CV-A6, 92.0%; CV-A16, 100%), sensitivity (EV-A71, 96.5%; CV-A6, 95.8%; CV-A16, 99.0%), and specificity (EV-A71, 100%; CV-A6, 99.9%; CV-A16, 99.9%) in testing clinical specimens (n=1049) during 2014-2016, superior to those of conventional RT-PCR. Overall, the multiplex rRT-PCR assays enabled highly sensitive detection and rapid simultaneous typing of EV-A71, CV-A6 and CV-A16, and enteroviruses, rendering them feasible and attractive methods for large-scale surveillance of enteroviruses associated with HFMD outbreaks. Copyright © 2017 Elsevier B.V. All rights reserved.

Rapid and sensitive detection of malachite green in aquaculture water by electrochemical preconcentration and surface-enhanced Raman scattering.

PubMed

Xu, Kai-Xuan; Guo, Mei-Hong; Huang, Yu-Ping; Li, Xiao-Dong; Sun, Jian-Jun

2018-04-01

A highly sensitive and rapid method of in-situ surface-enhanced Raman spectroscopy (SERS) combining with electrochemical preconcentration (EP) in detecting malachite green (MG) in aquaculture water was established. Ag nanoparticles (AgNPs) were synthesized and spread onto the surface of gold electrodes after centrifuging to produce SERS-active substrates. After optimizing the pH values, preconcentration potentials and times, in-situ EP-SERS detection was carried out. A sensitive and rapid analysis of the low-concentration MG was accomplished within 200s and the limit of detection was 2.4 × 10 -16 M. Copyright © 2017 Elsevier B.V. All rights reserved.

Potential of mid IR spectroscopy in the rapid label free identification of skin malignancies

NASA Astrophysics Data System (ADS)

Kastl, Lena; Kemper, Björn; Lloyd, Gavin R.; Nallala, Jayakrupakar; Stone, Nick; Naranjo, Valery; Penaranda, Francisco; Schnekenburger, Jürgen

2016-03-01

The rapid inspection of suspicious skin lesions for pathological cell types is the objective of optical point of care diagnostics technologies. A marker free fast diagnosis of skin malignancies would overcome the limitations of the current gold standard surgical biopsy. The time consuming and costly biopsy procedure requires the inspection of each sample by a trained pathologist, which limits the analysis of potentially malignant lesions. Optical technologies like RAMAN or infrared spectroscopy, which provide both, localization and chemical information, can be used to differentiate malignant from healthy tissue by the analysis of multi cell structures and cell type specific spectra. We here report the application of midIR spectroscopy towards fast and reliable skin diagnostics. Within the European research project MINERVA we developed standardized in vitro skin systems with increasing complexity, from single skin cell types as fibroblasts, keratinocytes and melanoma cells, to mixtures of these and finally three dimensional human skin equivalents. The standards were characterized in the established midIR range and also with newly developed systems for fast imaging up to 12 μm. The analysis of the spectra by novel data processing algorithms demonstrated the clear separation of all cell types, especially the tumor cells. The signals from single cell layers were sufficient for cell type differentiation. We have compared different midIR systems and found all of them suitable for specific cell type identification. Our data demonstrate the potential of midIR spectroscopy for fast image acquisition and an improved data processing as sensitive and specific optical biopsy technology.

Rapid optimization of MRM-MS instrument parameters by subtle alteration of precursor and product m/z targets.

PubMed

Sherwood, Carly A; Eastham, Ashley; Lee, Lik Wee; Risler, Jenni; Mirzaei, Hamid; Falkner, Jayson A; Martin, Daniel B

2009-07-01

Multiple reaction monitoring (MRM) is a highly sensitive method of targeted mass spectrometry (MS) that can be used to selectively detect and quantify peptides based on the screening of specified precursor peptide-to-fragment ion transitions. MRM-MS sensitivity depends critically on the tuning of instrument parameters, such as collision energy and cone voltage, for the generation of maximal product ion signal. Although generalized equations and values exist for such instrument parameters, there is no clear indication that optimal signal can be reliably produced for all types of MRM transitions using such an algorithmic approach. To address this issue, we have devised a workflow functional on both Waters Quattro Premier and ABI 4000 QTRAP triple quadrupole instruments that allows rapid determination of the optimal value of any programmable instrument parameter for each MRM transition. Here, we demonstrate the strategy for the optimizations of collision energy and cone voltage, but the method could be applied to other instrument parameters, such as declustering potential, as well. The workflow makes use of the incremental adjustment of the precursor and product m/z values at the hundredth decimal place to create a series of MRM targets at different collision energies that can be cycled through in rapid succession within a single run, avoiding any run-to-run variability in execution or comparison. Results are easily visualized and quantified using the MRM software package Mr. M to determine the optimal instrument parameters for each transition.

Rapid Optimization of MRM-MS Instrument Parameters by Subtle Alteration of Precursor and Product m/z Targets

PubMed Central

Sherwood, Carly A.; Eastham, Ashley; Lee, Lik Wee; Risler, Jenni; Mirzaei, Hamid; Falkner, Jayson A.; Martin, Daniel B.

2009-01-01

Multiple reaction monitoring (MRM) is a highly sensitive method of targeted mass spectrometry (MS) that can be used to selectively detect and quantify peptides based on the screening of specified precursor peptide-to-fragment ion transitions. MRM-MS sensitivity depends critically on the tuning of instrument parameters, such as collision energy and cone voltage, for the generation of maximal product ion signal. Although generalized equations and values exist for such instrument parameters, there is no clear indication that optimal signal can be reliably produced for all types of MRM transitions using such an algorithmic approach. To address this issue, we have devised a workflow functional on both Waters Quattro Premier and ABI 4000 QTRAP triple quadrupole instruments that allows rapid determination of the optimal value of any programmable instrument parameter for each MRM transition. Here, we demonstrate the strategy for the optimizations of collision energy and cone voltage, but the method could be applied to other instrument parameters, such as declustering potential, as well. The workflow makes use of the incremental adjustment of the precursor and product m/z values at the hundredth decimal place to create a series of MRM targets at different collision energies that can be cycled through in rapid succession within a single run, avoiding any run-to-run variability in execution or comparison. Results are easily visualized and quantified using the MRM software package Mr. M to determine the optimal instrument parameters for each transition. PMID:19405522

A rapid, partial leach and organic separation for the sensitive determination of Ag, Bi, Cd, Cu, Mo, Pb, Sb, and Zn in surface geologic materials by flame atomic absorption

USGS Publications Warehouse

Viets, J.G.; Clark, J.R.; Campbell, W.L.

1984-01-01

A solution of dilute hydrochloric acid, ascorbic acid, and potassium iodide has been found to dissolve weakly bound metals in soils, stream sediments, and oxidized rocks. Silver, Bi, Cd, Cu, Mo, Pb, Sb, and Zn are selectively extracted from this solution by a mixture of Aliquat 336 (tricaprylyl methyl ammonium chloride) and MIBK (methyl isobutyl ketone). Because potentially interfering major and minor elements do not extract, the organic separation allows interference-free determinations of Ag and Cd to the 0.05 ppm level, Mo, Cu, and Zn to 0.5 ppm, and Bi, Pb, and Sb to 1 ppm in the sample using flame atomic absorption spectroscopy. The analytical absorbance values of the organic solution used in the proposed method are generally enhanced more than threefold as compared to aqueous solutions, due to more efficient atomization and burning characteristics. The leaching and extraction procedures are extremely rapid; as many as 100 samples may be analyzed per day, yielding 800 determinations, and the technique is adaptable to field use. The proposed method was compared to total digestion methods for geochemical reference samples as well as soils and stream sediments from mineralized and unmineralized areas. The partial leach showed better anomaly contrasts than did total digestions. Because the proposed method is very rapid and is sensitive to pathfinder elements for several types of ore deposits, it should be useful for reconnaissance surveys for concealed deposits. ?? 1984.

A recombinant estrogen receptor fragment-based homogeneous fluorescent assay for rapid detection of estrogens.

PubMed

Wang, Dan; Xie, Jiangbi; Zhu, Xiaocui; Li, Jinqiu; Zhao, Dongqin; Zhao, Meiping

2014-05-15

In this work, we demonstrate a novel estrogenic receptor fragment-based homogeneous fluorescent assay which enables rapid and sensitive detection of 17β-estradiol (E2) and other highly potent estrogens. A modified human estrogenic receptor fragment (N-His × 6-hER270-595-C-Strep tag II) has been constructed that contains amino acids 270-595 of wild-type human estrogenic receptor α (hER270-595) and two specific tags (6 × His and Strep tag II) fused to the N and C terminus, respectively. The designed receptor protein fragment could be easily produced by prokaryotic expression with high yield and high purity. The obtained protein exhibits high binding affinity to E2 and the two tags greatly facilitate the application of the recombinant protein. Taking advantage of the unique spectroscopic properties of coumestrol (CS), a fluorescent phytoestrogen, a CS/hER270-595-based fluorescent assay has been developed which can sensitively respond to E2 within 1.0 min with a linear working range from 0.1 to 20 ng/mL and a limit of detection of 0.1 ng/mL. The assay was successfully applied for rapid detection of E2 in the culture medium of rat hippocampal neurons. The method also holds great potential for high-throughput monitoring the variation of estrogen levels in complex biological fluids, which is crucial for investigation of the molecular basis of various estrogen-involved processes. Copyright © 2013 Elsevier B.V. All rights reserved.

The slowpoke gene is necessary for rapid ethanol tolerance in Drosophila.

PubMed

Cowmeadow, R B; Krishnan, H R; Atkinson, N S

2005-10-01

Ethanol is one of the most commonly used drugs in the world. We are interested in the compensatory mechanisms used by the nervous system to counter the effects of ethanol intoxication. Recently, the slowpoke BK-type calcium-activated potassium channel gene has been shown to be involved in ethanol sensitivity in Caenorhabditis elegans and in rapid tolerance to the anesthetic benzyl alcohol in Drosophila. We used Drosophila mutants to investigate the role of slowpoke in rapid tolerance to sedation with ethanol vapor. Rapid tolerance was defined as a reduction in the sedative phase caused by a single previous sedation. The ethanol and water contents of flies were measured to determine if pharmacodynamic changes could account for tolerance. A saturated ethanol air stream caused sedation in <20 min and resulted in rapid tolerance that was apparent 4 hr after sedation. Two independently isolated null mutations in the slowpoke gene eliminated the capacity for tolerance. In addition, a third mutation that blocked expression specifically in the nervous system also blocked rapid tolerance. Water measurements showed that both ethanol and mock sedation caused equivalent dehydration. Furthermore, a single prior exposure to ethanol did not cause a change in the ethanol clearance rate. Rapid tolerance, measured as a reduction in the duration of sedation, is a pharmacokinetic response to ethanol that does not occur without slowpoke expression in the nervous system in Drosophila. The slowpoke channel must be involved in triggering or producing a homeostatic mechanism that opposes the sedative effects of ethanol.

MyD88-dependent dendritic and epithelial cell crosstalk orchestrates immune responses to allergens.

PubMed

Thomas, S Y; Whitehead, G S; Takaku, M; Ward, J M; Xu, X; Nakano, K; Lyons-Cohen, M R; Nakano, H; Gowdy, K M; Wade, P A; Cook, D N

2018-05-01

Sensitization to inhaled allergens is dependent on activation of conventional dendritic cells (cDCs) and on the adaptor molecule, MyD88. However, many cell types in the lung express Myd88, and it is unclear how signaling in these different cell types reprograms cDCs and leads to allergic inflammation of the airway. By combining ATAC-seq with RNA profiling, we found that MyD88 signaling in cDCs maintained open chromatin at select loci even at steady state, allowing genes to be rapidly induced during allergic sensitization. A distinct set of genes related to metabolism was indirectly controlled in cDCs through MyD88 signaling in airway epithelial cells (ECs). In mouse models of asthma, Myd88 expression in ECs was critical for eosinophilic inflammation, whereas Myd88 expression in cDCs was required for Th17 cell differentiation and consequent airway neutrophilia. Thus, both cell-intrinsic and cell-extrinsic MyD88 signaling controls gene expression in cDCs and orchestrates immune responses to inhaled allergens.

A rapid method for determining salinomycin and monensin sensitivity in Eimeria tenella

USDA-ARS?s Scientific Manuscript database

Standard methods of determining the ionophore sensitivity of Eimeria rely on infecting chickens with an isolate or a mixture of Eimeria spp. oocysts in the presence of different anti-coccidial drugs. The purpose of this study was to develop a rapid in vitro method for assessing salinomycin and mone...

Time-Resolved Fluorescent Immunochromatography of Aflatoxin B1 in Soybean Sauce: A Rapid and Sensitive Quantitative Analysis.

PubMed

Wang, Du; Zhang, Zhaowei; Li, Peiwu; Zhang, Qi; Zhang, Wen

2016-07-14

Rapid and quantitative sensing of aflatoxin B1 with high sensitivity and specificity has drawn increased attention of studies investigating soybean sauce. A sensitive and rapid quantitative immunochromatographic sensing method was developed for the detection of aflatoxin B1 based on time-resolved fluorescence. It combines the advantages of time-resolved fluorescent sensing and immunochromatography. The dynamic range of a competitive and portable immunoassay was 0.3-10.0 µg·kg(-1), with a limit of detection (LOD) of 0.1 µg·kg(-1) and recoveries of 87.2%-114.3%, within 10 min. The results showed good correlation (R² > 0.99) between time-resolved fluorescent immunochromatographic strip test and high performance liquid chromatography (HPLC). Soybean sauce samples analyzed using time-resolved fluorescent immunochromatographic strip test revealed that 64.2% of samples contained aflatoxin B1 at levels ranging from 0.31 to 12.5 µg·kg(-1). The strip test is a rapid, sensitive, quantitative, and cost-effective on-site screening technique in food safety analysis.

Validation of paper-based assay for rapid blood typing.

PubMed

Al-Tamimi, Mohammad; Shen, Wei; Zeineddine, Rania; Tran, Huy; Garnier, Gil

2012-02-07

We developed and validated a new paper-based assay for the detection of human blood type. Our method involves spotting a 3 μL blood sample on a paper surface where grouping antibodies have already been introduced. A thin film chromatograph tank was used to chromatographically elute the blood spot with 0.9% NaCl buffer for 10 min by capillary absorption. Agglutinated red blood cells (RBCs) were fixed on the paper substrate, resulting in a high optical density of the spot, with no visual trace in the buffer wicking path. Conversely, nonagglutinated RBCs could easily be eluted by the buffer and had low optical density of the spot and clearly visible trace of RBCs in the buffer wicking path. Different paper substrates had comparable ability to fix agglutinated blood, while a more porous substrate like Kleenex paper had enhanced ability to elute nonagglutinated blood. Using optimized conditions, a rapid assay for detection of blood groups was developed by spotting blood to antibodies absorbed to paper and eluted with 200 μL of 0.9% NaCl buffer directly by pipetting. RBCs fixation on paper accurately detected blood groups (ABO and RhD) using ascending buffer for 10 min or using a rapid elution step in 100/100 blood samples including 4 weak AB and 4 weak RhD samples. The assay has excellent reproducibility where the same blood group was obtained in 26 samples assessed in 2 different days. Agglutinated blood fixation on porous paper substrate provides a new, simple, and sensitive assay for rapid detection of blood group for point-of-care applications. © 2011 American Chemical Society

Effect of diet induced obesity or type 1 or type 2 diabetes on corneal nerves and peripheral neuropathy in C57Bl/6J mice

PubMed Central

Yorek, Matthew S.; Obrosov, Alexander; Shevalye, Hanna; Holmes, Amey; Harper, Matthew M.; Kardon, Randy H.; Yorek, Mark A.

2015-01-01

We determined the impact diet induced obesity (DIO) and types 1 and 2 diabetes has on peripheral neuropathy with emphasis on corneal nerve structural changes in C57Bl/6J mice. Endpoints examined included nerve conduction velocity, response to thermal and mechanical stimuli and innervation of the skin and cornea. DIO mice and to a greater extent type 2 diabetic mice were insulin resistant. DIO and both types 1 and 2 diabetic mice developed motor and sensory nerve conduction deficits. In the cornea of DIO and type 2 diabetic mice there was a decrease in sub-epithelial corneal nerves, innervation of the corneal epithelium and corneal sensitivity. Type 1 diabetic mice did not present with any significant changes in corneal nerve structure until after 20 weeks of hyperglycemia. DIO and type 2 diabetic mice developed corneal structural damage more rapidly than type 1 diabetic mice even though hemoglobin A1C values were significantly higher in type 1 diabetic mice. This suggests that DIO with or without hyperglycemia contributes to development and progression of peripheral neuropathy and nerve structural damage in the cornea. PMID:25858759

Monte Carlo Study Elucidates the Type 1/Type 2 Choice in Apoptotic Death Signaling in Healthy and Cancer Cells

PubMed Central

Raychaudhuri, Subhadip; Raychaudhuri, Somkanya C

2013-01-01

Apoptotic cell death is coordinated through two distinct (type 1 and type 2) intracellular signaling pathways. How the type 1/type 2 choice is made remains a central problem in the biology of apoptosis and has implications for apoptosis related diseases and therapy. We study the problem of type 1/type 2 choice in silico utilizing a kinetic Monte Carlo model of cell death signaling. Our results show that the type 1/type 2 choice is linked to deterministic versus stochastic cell death activation, elucidating a unique regulatory control of the apoptotic pathways. Consistent with previous findings, our results indicate that caspase 8 activation level is a key regulator of the choice between deterministic type 1 and stochastic type 2 pathways, irrespective of cell types. Expression levels of signaling molecules downstream also regulate the type 1/type 2 choice. A simplified model of DISC clustering elucidates the mechanism of increased active caspase 8 generation and type 1 activation in cancer cells having increased sensitivity to death receptor activation. We demonstrate that rapid deterministic activation of the type 1 pathway can selectively target such cancer cells, especially if XIAP is also inhibited; while inherent cell-to-cell variability would allow normal cells stay protected. PMID:24709706

Detection of carbapenemase activity in Enterobacteriaceae using LC-MS/MS in comparison with the neo-rapid CARB kit using direct visual assessment and colorimetry.

PubMed

Huber, Charlotte A; Sidjabat, Hanna E; Zowawi, Hosam M; Kvaskoff, David; Reed, Sarah; McNamara, John F; McCarthy, Kate L; Harris, Patrick; Toh, Benjamin; Wailan, Alexander M; Paterson, David L

2016-12-01

It has been described that the sensitivity of the Carba NP test may be low in the case of OXA-48-like carbapenamases and mass spectrometry based methods as well as a colorimetry based method have been described as alternatives. We evaluated 84 Enterobacteriaceae isolates including 31 OXA-48-like producing isolates and 13 isolates that produced either an imipenemase (IMP; n=8), New Delhi metallo-β-lactamase (NDM; n=3), or Klebsiella pneumoniae carbapenemase (KPC; n=2), as well as 40 carbapenemase negative Enterobacteriaceae isolates. We used the Neo-Rapid CARB kit, assessing the results with the unaided eye and compared it with a colorimetric approach. Furthermore, we incubated the isolates in growth media with meropenem and measured the remaining meropenem after one and 2h of incubation, respectively, using liquid chromatography tandem mass spectrometry (LC-MS/MS). Whilst all carbapenemase producing isolates with the exception of the OXA-244 producer tested positive for both the Neo-rapid CARB test using the unaided eye or colorimetry, and the 13 isolates producing either IMP, NDM or KPC hydrolysed the meropenem in the media almost completely after 2h of incubation, the 31 OXA-48-like producing isolates exhibited very variable hydrolytic activity when incubated in growth media with meropenem. In our study, the Neo-Rapid CARB test yielded a sensitivity of 98% for both the traditional and the colorimetric approach with a specificity of 95% and 100% respectively. Our results indicate that the Neo-Rapid CARB test may have use for the detection of OXA-48 type carbapenemases and that it may be particularly important to ensure bacterial lysis for the detection of these weaker hydrolysers. Copyright © 2016 The Authors. Published by Elsevier B.V. All rights reserved.

Multiplexed instrument-free meningitis diagnosis on a polymer/paper hybrid microfluidic biochip.

PubMed

Dou, Maowei; Sanjay, Sharma T; Dominguez, Delfina C; Liu, Peng; Xu, Feng; Li, XiuJun

2017-01-15

Neisseria meningitidis (N. meningitidis), Streptococcus pneumoniae (S. pneumoniae), and Haemophilus influenzae type b (Hib) are three most common pathogens accounting for most bacterial meningitis, a serious global infectious disease with high fatality, especially in developing nations. Because the treatment and antibiotics differ among each type, the identification of the exact bacteria causing the disease is vital. Herein, we report a polymer/paper hybrid microfluidic biochip integrated with loop-mediated isothermal amplification (LAMP) for multiplexed instrument-free diagnosis of these three major types of bacterial meningitis, with high sensitivity and specificity. Results can be visually observed by the naked eye or imaged by a smartphone camera under a portable UV light source. Without using any specialized laboratory instrument, the limits of detection of a few DNA copies per LAMP zone for N. meningitidis, S. pneumoniae and Hib were achieved within 1h. In addition, these three types of microorganisms spiked in artificial cerebrospinal fluid (ACSF) were directly detected simultaneously, avoiding cumbersome sample preparation procedures in conventional methods. Compared with the paper-free non-hybrid microfluidic biochip over a period of three months, the hybrid microfluidic biochip was found to have a much longer shelf life. Hence, this rapid, instrument-free and highly sensitive microfluidic approach has great potential for point-of-care (POC) diagnosis of multiple infectious diseases simultaneously, especially in resource-limited settings. Copyright © 2016 Elsevier B.V. All rights reserved.

A new simple and rapid LC-ESI-MS/MS method for quantification of plasma oxysterols as dimethylaminobutyrate esters. Its successful use for the diagnosis of Niemann-Pick type C disease.

PubMed

Boenzi, Sara; Deodato, Federica; Taurisano, Roberta; Martinelli, Diego; Verrigni, Daniela; Carrozzo, Rosalba; Bertini, Enrico; Pastore, Anna; Dionisi-Vici, Carlo; Johnson, David W

2014-11-01

Two oxysterols, cholestan-3β,5α,6β-triol (C-triol) and 7-ketocholesterol (7-KC), have been recently proposed as diagnostic markers of Niemann-Pick type C (NP-C) disease, representing a potential alternative diagnostic tool to the more invasive and time consuming filipin test in cultured fibroblasts. Usually, the oxysterols are detected and quantified by liquid chromatography-tandem mass spectrometry (LC-MS/MS) method using atmospheric pressure chemical ionization (APCI) or electro-spray-ionization (ESI) sources, after a variety of derivatization procedures to enhance sensitivity. We developed a sensitive LC-MS/MS method to quantify the oxysterols in plasma as dimethylaminobutyrate ester, suitable for ESI analysis. This method, with an easy liquid-phase extraction and a short derivatization procedure, has been validated to demonstrate specificity, linearity, recovery, lowest limit of quantification, accuracy and precision. The assay was linear over a concentration range of 0.5-200ng/mL for C-triol and 1.0-200ng/mL for 7-KC. Intra-day and inter-day coefficients of variation (CV%) were <15% for both metabolites. Receiver operating characteristic analysis estimates that the area under curve was 0.998 for C-triol, and 0.972 for 7-KC, implying a significant discriminatory power for the method in this patient population of both oxysterols. In summary, our method provides a simple, rapid and non-invasive diagnostic tool for the biochemical diagnosis of NP-C disease. Copyright © 2014 Elsevier B.V. All rights reserved.

Lyssavirus Detection and Typing Using Pyrosequencing▿#‖

PubMed Central

De Benedictis, Paola; De Battisti, Cristian; Dacheux, Laurent; Marciano, Sabrina; Ormelli, Silvia; Salomoni, Angela; Caenazzo, Silvia Tiozzo; Lepelletier, Anthony; Bourhy, Hervé; Capua, Ilaria; Cattoli, Giovanni

2011-01-01

Rabies is a fatal zoonosis caused by a nonsegmented negative-strand RNA virus, namely, rabies virus (RABV). Apart from RABV, at least 10 additional species are known as rabies-related lyssaviruses (RRVs), and some of them are responsible for occasional spillovers into humans. More lyssaviruses have also been detected recently in different bat ecosystems, thanks to the application of molecular diagnostic methods. Due to the variety of the members of the genus Lyssavirus, there is the necessity to develop a reliable molecular assay for rabies diagnosis able to detect and differentiate among the existing rabies and rabies-related viruses. In the present study, a pyrosequencing protocol targeting the 3′ terminus of the nucleoprotein (N) gene was applied for the rapid characterization of lyssaviruses. Correct identification of species was achieved for each sample tested. Results from the pyrosequencing assay were also confirmed by those obtained using the Sanger sequencing method. A pan-lyssavirus one-step reverse transcription (RT)-PCR was developed within the framework of the pyrosequencing procedure. The sensitivity (Se) of the one-step RT-PCR assay was determined by using in vitro-transcribed RNA and serial dilutions of titrated viruses. The assay demonstrated high analytical and relative specificity (Sp) (98.94%) and sensitivity (99.71%). To date, this is the first case in which pyrosequencing has been applied for lyssavirus identification using a cheaper diagnostic approach than the one for all the other protocols for rapid typing that we are acquainted with. Results from this study indicate that this procedure is suitable for lyssavirus detection in samples of both human and animal origin. PMID:21389152

Optimization and validation of a fast amplification protocol for AmpFlSTR® Profiler Plus® for rapid forensic human identification.

PubMed

Laurin, Nancy; Frégeau, Chantal

2012-01-01

The goal of this work was to optimize and validate a fast amplification protocol for the multiplex amplification of the STR loci included in AmpFlSTR(®) Profiler Plus(®) to expedite human DNA identification. By modifying the cycling conditions and by combining the use of a DNA polymerase optimized for high speed PCR (SpeedSTAR™ HS) and a more efficient thermal cycler instrument (Bio-RAD C1000™), we were able to reduce the amplification process from 4h to 26 min. No modification to the commercial AmpFlSTR(®) Profiler Plus(®) primer mix was required. When compared to the current Royal Canadian Mounted Police (RCMP) amplification protocol, no differences with regards to specificity, sensitivity, heterozygote peak height ratios and overall profile balance were noted. Moreover, complete concordance was obtained with profiles previously generated with the standard amplification protocol and minor alleles in mixture samples were reliably typed. An increase in n-4 stutter ratios (2.2% on average for all loci) was observed for profiles amplified with the fast protocol compared to the current procedure. Our results document the robustness of this rapid amplification protocol for STR profiling using the AmpFlSTR(®) Profiler Plus(®) primer set and demonstrate that comparable data can be obtained in substantially less time. This new approach could provide an alternative option to current multiplex STR typing amplification protocols in order to increase throughput or expedite time-sensitive cases. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

Performance of HIV Rapid Tests Among Breastfeeding, Malawian Infants.

PubMed

Smith, Emily R; Sheahan, Anna D; Heyderman, Robert S; Miller, William C; Wheeler, Stephanie; Hudgens, Michael; Nelson, Julie A E; Dube, Queen; Van Rie, Annelies

2017-04-01

Timely, accurate and affordable testing algorithms at point-of-care are critical for early infant HIV diagnosis and initiation of antiretroviral therapy in the postpartum period. We aimed to assess the utility of HIV rapid tests for young, breast-fed HIV-exposed infants in resource limited, high HIV burden settings. We collected data on the performance of 2 commonly used rapid tests (Determine and Unigold) in Malawi between 2008 and 2012 or at the University of North Carolina between 2014 and 2015. For each 3-month interval between ages 3 and 18 months, we calculated the sensitivity, specificity, positive and negative predictive values of each test compared with the HIV DNA/RNA PCR gold standard. We also assessed the utility of each rapid test to diagnose incident HIV infection during the breastfeeding period. Among 121 HIV-exposed infants who were negative at age 6 weeks, 21 (17.2%) became infected by 18 months. At 3 months of age, both rapid tests had minimal clinical value with specificity values of 7.0% [95% confidence interval (CI): 2.3-15.7] for Determine and 19.4% (95% CI: 11.1-30.5) for Unigold. Starting at age 6 and 9 months, the Unigold test could be used as a screening tool in the follow-up of HIV-exposed infants with specificity values of 83.7% (95% CI: 74.4-89.9) and 97.7% (95% CI: 94.6-99.7), respectively. Starting at age 12 months, the type of test became less important as both tests performed well in identifying HIV-free children, although both tests failed to detect some incident HIV infections. Updated guidelines for the use of rapid tests in young HIV-exposed children that explicitly take type of test and infant age into account are urgently needed to ensure optimal care for the 1.5 million HIV-exposed infants born annually.

Performance of a New Rapid Immunoassay Test Kit for Point-of-Care Diagnosis of Significant Bacteriuria

PubMed Central

Cox, Marsha E.; DiNello, Robert K.; Geisberg, Mark; Abbott, April; Roberts, Pacita L.; Hooton, Thomas M.

2015-01-01

Urinary tract infections (UTIs) are frequently encountered in clinical practice and most commonly caused by Escherichia coli and other Gram-negative uropathogens. We tested RapidBac, a rapid immunoassay for bacteriuria developed by Silver Lake Research Corporation (SLRC), compared with standard bacterial culture using 966 clean-catch urine specimens submitted to a clinical microbiology laboratory in an urban academic medical center. RapidBac was performed in accordance with instructions, providing a positive or negative result in 20 min. RapidBac identified as positive 245/285 (sensitivity 86%) samples with significant bacteriuria, defined as the presence of a Gram-negative uropathogen or Staphylococcus saprophyticus at ≥103 CFU/ml. The sensitivities for Gram-negative bacteriuria at ≥104 CFU/ml and ≥105 CFU/ml were 96% and 99%, respectively. The specificity of the test, detecting the absence of significant bacteriuria, was 94%. The sensitivity and specificity of RapidBac were similar on samples from inpatient and outpatient settings, from male and female patients, and across age groups from 18 to 89 years old, although specificity was higher in men (100%) compared with that in women (92%). The RapidBac test for bacteriuria may be effective as an aid in the point-of-care diagnosis of UTIs especially in emergency and primary care settings. PMID:26063858

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

Chemiluminescence immunoassay for the rapid and sensitive detection of antibody against porcine parvovirus by using horseradish peroxidase/detection antibody-coated gold nanoparticles as nanoprobes.

PubMed

Zhou, Yuan; Zhou, Tao; Zhou, Rui; Hu, Yonggang

2014-06-01

A rapid, simple, facile, sensitive and enzyme-amplified chemiluminescence immunoassay (CLIA) method to detect antibodies against porcine parvovirus has been developed. Horseradish peroxidase (HRP) and the detection antibody were simultaneously co-immobilized on the surface of gold nanoparticles using the electrostatic method to form gold nanoparticle-based nanoprobes. This nanoprobe was employed in a sandwich-type CLIA, which enables CL signal readout from enzymatic catalysis and results in signal amplification. The presence of porcine parvovirus infection was determined in porcine parvovirus antibodies by measuring the CL intensity caused by the reaction of HRP-luminol with H2 O2 . Under optimal conditions, the obtained calibration plot for the standard positive serum was approximately linear within the dilution range of 1:80 to 1:5120. The limit of detection for the assay was 1:10,240 (S/N = 3), which is much lower than that typically achieved with an enzyme-linked immunosorbent assay (1:160; S/N = 3). A series of repeatability measurements using 1:320-fold diluted standard positive serum gave reproducible results with a relative standard deviation of 4.9% (n = 11). The ability of the immunosensor to analyze clinical samples was tested on porcine sera. The immunosensor had an efficiency of 90%, a sensitivity of 93.3%, and a specificity of 87.5% relative to the enzyme-linked immunosorbent assay results. Copyright © 2013 John Wiley & Sons, Ltd.

Identification of a novel cyclosporin-sensitive element in the human tumor necrosis factor alpha gene promoter

PubMed Central

1993-01-01

Tumor necrosis factor alpha (TNF-alpha), a cytokine with pleiotropic biological effects, is produced by a variety of cell types in response to induction by diverse stimuli. In this paper, TNF-alpha mRNA is shown to be highly induced in a murine T cell clone by stimulation with T cell receptor (TCR) ligands or by calcium ionophores alone. Induction is rapid, does not require de novo protein synthesis, and is completely blocked by the immunosuppressant cyclosporin A (CsA). We have identified a human TNF-alpha promoter element, kappa 3, which plays a key role in the calcium-mediated inducibility and CsA sensitivity of the gene. In electrophoretic mobility shift assays, an oligonucleotide containing kappa 3 forms two DNA protein complexes with proteins that are present in extracts from unstimulated T cells. These complexes appear in nuclear extracts only after T cell stimulation. Induction of the inducible nuclear complexes is rapid, independent of protein synthesis, and blocked by CsA, and thus, exactly parallels the induction of TNF-alpha mRNA by TCR ligands or by calcium ionophore. Our studies indicate that the kappa 3 binding factor resembles the preexisting component of nuclear factor of activated T cells. Thus, the TNF-alpha gene is an immediate early gene in activated T cells and provides a new model system in which to study CsA-sensitive gene induction in activated T cells. PMID:8376940

Dictyostelium discoideum mutants with temperature-sensitive defects in endocytosis

PubMed Central

1994-01-01

We have isolated and characterized temperature-sensitive endocytosis mutants in Dictyostelium discoideum. Dictyostelium is an attractive model for genetic studies of endocytosis because of its high rates of endocytosis, its reliance on endocytosis for nutrient uptake, and tractable molecular genetics. Endocytosis-defective mutants were isolated by a fluorescence-activated cell sorting (FACS) as cells unable to take up a fluorescent marker. One temperature-sensitive mutant (indy1) was characterized in detail and found to exhibit a complete block in fluid phase endocytosis at the restrictive temperature, but normal rates of endocytosis at the permissive temperature. Likewise, a potential cell surface receptor that was rapidly internalized in wild-type cells and indy1 cells at the permissive temperature was poorly internalized in indy1 under restrictive conditions. Growth was also completely arrested at the restrictive temperature. The endocytosis block was rapidly induced upon shift to the restrictive temperature and reversed upon return to normal conditions. Inhibition of endocytosis was also specific, as other membrane-trafficking events such as phagocytosis, secretion of lysosomal enzymes, and contractile vacuole function were unaffected at the restrictive temperature. Because recycling and transport to late endocytic compartments were not affected, the site of the defect's action is probably at an early step in the endocytic pathway. Additionally, indy1 cells were unable to proceed through the normal development program at the restrictive temperature. Given the tight functional and growth phenotypes, the indy1 mutant provides an opportunity to isolate genes responsible for endocytosis in Dictyostelium by complementation cloning. PMID:7929583

Rapid and simultaneous detection of Salmonella spp., Escherichia coli O157, and Listeria monocytogenes by magnetic capture hybridization and multiplex real-time PCR.

PubMed

Carloni, Elisa; Rotundo, Luca; Brandi, Giorgio; Amagliani, Giulia

2018-05-25

The application of rapid, specific, and sensitive methods for pathogen detection and quantification is very advantageous in diagnosis of human pathogens in several applications, including food analysis. The aim of this study was the evaluation of a method for the multiplexed detection and quantification of three significant foodborne pathogenic species (Escherichia coli O157, Salmonella spp., and Listeria monocytogenes). The assay combines specific DNA extraction by multiplex magnetic capture hybridization (mMCH) with multiplex real-time PCR. The amplification assay showed linearity in the range 10 6 -10 genomic units (GU)/PCR for each co-amplified species. The sensitivity corresponded to 1 GU/PCR for E. coli O157 and L. monocytogenes, and 10 GU/PCR for Salmonella spp. The immobilization process and the hybrid capture of the MCH showed good efficiency and reproducibility for all targets, allowing the combination in equal amounts of the different nanoparticle types in mMCH. MCH and mMCH efficiencies were similar. The detection limit of the method was 10 CFU in samples with individual pathogens and 10 2  CFU in samples with combination of the three pathogens in unequal amounts (amount's differences of 2 or 3 log). In conclusion, this multiplex molecular platform can be applied to determine the presence of target species in food samples after culture enrichment. In this way, this method could be a time-saving and sensitive tool to be used in routine diagnosis.

Biological sensing with surface-enhanced Raman spectroscopy (SERS) using a facile and rapid silver colloid-based synthesis technique

NASA Astrophysics Data System (ADS)

Smyth, C.; Mehigan, S.; Rakovich, Y. P.; Bell, S. E. J.; McCabe, E. M.

2011-03-01

Optical techniques towards the realisation of sensitive and selective biosensing platforms have received a considerable amount of attention in recent times. Techniques based on interferometry, surface plasmon resonance, field-effect transistors and waveguides have all proved popular, and in particular, spectroscopy offers a large range of options. Raman spectroscopy has always been viewed as an information rich technique in which the vibrational frequencies reveal a lot about the structure of a compound. The issue with Raman spectroscopy has traditionally been that its rather low cross section leads to poor limits-of-detection. In response to this problem, Surface-enhanced Raman Scattering (SERS), which increases sensitivity by bringing the sample in contact with many types of enhanceing substrates, has been developed. Here we discuss a facile and rapid technique for the detection of pterins using colloidal silver suspensions. Pteridine compounds are a family of biochemicals, heterocyclic in structure, and employed in nature as components of colour pigmentation and also as facilitators for many metabolic pathways, particularly those relating to the amino acid hydroxylases. In this work, xanthopterin, isoxanthopterin and 7,8- dihydrobiopterin have been examined whilst absorbed to SERS-active silver colloids. SERS, while far more sensitive than regular Raman spectroscopy, has its own issues relating to the reproducibility of substrates. In order to obtain quantitative data for the pteridine compounds mentioned above, exploratory studies of methods for introducing an internal standard for normalisation of the signals have been carried out.e

Genetic diversity of Plasmodium falciparum histidine-rich protein 2 (PfHRP2) and its effect on the performance of PfHRP2-based rapid diagnostic tests.

PubMed

Baker, Joanne; McCarthy, James; Gatton, Michelle; Kyle, Dennis E; Belizario, Vicente; Luchavez, Jennifer; Bell, David; Cheng, Qin

2005-09-01

Rising costs of antimalarial agents are increasing the demand for accurate diagnosis of malaria. Rapid diagnostic tests (RDTs) offer great potential to improve the diagnosis of malaria, particularly in remote areas. Many RDTs are based on the detection of Plasmodium falciparum histidine-rich protein (PfHRP) 2, but reports from field tests have questioned their sensitivity and reliability. We hypothesize that the variability in the results of PfHRP2-based RDTs is related to the variability in the target antigen. We tested this hypothesis by examining the genetic diversity of PfHRP2, which includes numerous amino acid repeats, in 75 P. falciparum lines and isolates originating from 19 countries and testing a subset of parasites by use of 2 PfHRP2-based RDTs. We observed extensive diversity in PfHRP2 sequences, both within and between countries. Logistic regression analysis indicated that 2 types of repeats were predictive of RDT detection sensitivity (87.5% accuracy), with predictions suggesting that only 84% of P. falciparum parasites in the Asia-Pacific region are likely to be detected at densities < or = 250 parasites/microL. Our data also indicated that PfHRP3 may play a role in the performance of PfHRP2-based RDTs. These findings provide an alternative explanation for the variable sensitivity in field tests of malaria RDTs that is not due to the quality of the RDTs.

Quantitative, equal carbon response HSQC experiment, QEC-HSQC

NASA Astrophysics Data System (ADS)

Mäkelä, Valtteri; Helminen, Jussi; Kilpeläinen, Ilkka; Heikkinen, Sami

2016-10-01

Quantitative NMR has become increasingly useful and popular in recent years, with many new and emerging applications in metabolomics, quality control, reaction monitoring and other types of mixture analysis. While sensitive and simple to acquire, the low resolving power of 1D 1H NMR spectra can be a limiting factor when analyzing complex mixtures. This drawback can be solved by observing a different type of nuclei offering improved resolution or with multidimensional experiments, such as HSQC. In this paper, we present a novel Quantitative, Equal Carbon HSQC (QEC-HSQC) experiment providing an equal response across different type of carbons regardless of the number of attached protons, in addition to an uniform response over a wide range of 1JCH couplings. This enables rapid quantification and integration over multiple signals without the need for complete resonance assignments and simplifies the integration of overlapping signals.

Accuracy of Rapid Fecal Calprotectin Test in Monitoring Inflammatory Bowel Diseases Under Treatment with TNFα Antagonists.

PubMed

Tursi, Antonio; Elisei, Walter; Picchio, Marcello; Giorgetti, GianMarco; Brandimarte, Giovanni

2015-05-01

Anti-TNFα antibodies are effective in treating inflammatory bowel diseases (IBDs) unresponsive to the standard treatments. Information about the role of rapid fecal calprotectin (FC) in monitoring ambulatory IBD patients under treatment with anti-TNFα is lacking. Our aim was to assess the accuracy of rapid FC in monitoring those patients. Seventy-two patients (38 males, 34 females, mean age 42.5 years, range 23-57 years), affected by ulcerative colitis (UC) (20 patients) or by Crohn's disease (CD) (52 patients) were treated with anti-TNFα antibodies. FC was assessed by a rapid semiquantitative test. With respect to the absence of clinical remission, FC test showed sensitivity of 71.8 %, specificity of 65.2 %, PPV of 41.8 %, and NPV of 86.9 %. In UC patients, FC test showed a sensitivity of 66.7 %, a specificity of 56.1 %, a PPV of 18.2 %, and a NPV of 92.0 %. In CD patients, FC test showed sensitivity of 70.6 %, specificity of 65.2 %, PPV of 50.0 %, and NPV of 81.8 %. With respect to the presence of endoscopic lesions, FC test showed sensitivity of 73.5 %, specificity of 96.0 %, PPV of 96.2 %, and NPV of 72.7 %. In UC patients, FC test showed sensitivity of 47.2 %, specificity of 84.6 %, PPV of 89.5 %, and NPV of 36.7 %. In CD patients, FC test showed sensitivity of 90.1 %, specificity of 79.7 %, PPV of 71.9 %, and NPV of 93.3 %. Diagnostic accuracy of rapid FC seems better in predicting persistence of endoscopic lesions than clinical remission in IBD patients under treatment with anti-TNFα.

The Dye Sensitized Photoelectrosynthesis Cell (DSPEC) for Solar Water Splitting and CO2 Reduction

NASA Astrophysics Data System (ADS)

Meyer, Thomas; Alibabaei, Leila; Sherman, Benjamin; Sheridan, Matthew; Ashford, Dennis; Lapides, Alex; Brennaman, Kyle; Nayak, Animesh; Roy, Subhangi; Wee, Kyung-Ryang; Gish, Melissa; Meyer, Jerry; Papanikolas, John

The dye-sensitized photoelectrosynthesis cell (DSPEC) integrates molecular level light absorption and catalysis with the bandgap properties of stable oxide materials such as TiO2 and NiO. Excitation of surface-bound chromophores leads to excited state formation and rapid electron or hole injection into the conduction or valence bands of n or p-type oxides. Addition of thin layers of TiO2 or NiO on the surfaces of mesoscopic, nanoparticle films of semiconductor or transparent conducting oxides to give core/shell structures provides a basis for accumulating multiple redox equivalents at catalysts for water oxidation or CO2 reduction. UNC EFRC Center for Solar Fuels, an Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences under Award Number DE-SC0001011.

Sensitive determination of phenolic acids in extra-virgin olive oil by capillary zone electrophoresis.

PubMed

Carrasco Pancorbo, Alegría; Cruces-Blanco, Carmen; Segura Carretero, Antonio; Fernández Gutiérrez, Alberto

2004-11-03

A sensitive, rapid, efficient, and reliable method for the separation and determination of phenolic acids by capillary zone electrophoresis has been carried out. A detailed method optimization was carried out to separate 14 different compounds by studying parameters such as pH, type and concentration of buffer, applied voltage, and injection time. The separation was performed within 16 min, using a 25 mM sodium borate buffer (pH 9.6) at 25 kV with 8 s of hydrodynamic injection. With this method and using a liquid-liquid extraction system, with recovery values around 95%, it has been possible to detect small quantities of phenolic acids in olive oil samples. This is apparently the first paper showing the quantification of this specific family of phenolic compounds in virgin olive oil samples.

Hydrogen gas sensors using a thin Ta2O5 dielectric film

NASA Astrophysics Data System (ADS)

Kim, Seongjeen

2014-12-01

A capacitive-type hydrogen gas sensor with a MIS (metal-insulator-semiconductor) structure was investigated for high-temperature applications. In this work, a tantalum oxide (Ta2O5) layer of tens of nanometers in thickness formed by oxidizing tantalum film in rapid thermal processing (RTP) was exploited with the purpose of sensitivity improvement. Silicon carbide (SiC), which is good even at high temperatures over 500 °C, was used as the substrate. We fabricated sensors composed of Pd/Ta2O5/SiC, and the dependences of the capacitance response properties and the I-V characteristics on the hydrogen concentration were analyzed from the temperature range of room temperature to 500 °C. As a result, our hydrogen sensor showed promising performance with respect to the sensitivity and the adaptability at high temperature.

Use of Tethered Enzymes as a Platform Technology for Rapid Analyte Detection

PubMed Central

Cohen, Roy; Lata, James P.; Lee, Yurim; Hernández, Jean C. Cruz; Nishimura, Nozomi; Schaffer, Chris B.; Mukai, Chinatsu; Nelson, Jacquelyn L.; Brangman, Sharon A.; Agrawal, Yash; Travis, Alexander J.

2015-01-01

Background Rapid diagnosis for time-sensitive illnesses such as stroke, cardiac arrest, and septic shock is essential for successful treatment. Much attention has therefore focused on new strategies for rapid and objective diagnosis, such as Point-of-Care Tests (PoCT) for blood biomarkers. Here we use a biomimicry-based approach to demonstrate a new diagnostic platform, based on enzymes tethered to nanoparticles (NPs). As proof of principle, we use oriented immobilization of pyruvate kinase (PK) and luciferase (Luc) on silica NPs to achieve rapid and sensitive detection of neuron-specific enolase (NSE), a clinically relevant biomarker for multiple diseases ranging from acute brain injuries to lung cancer. We hypothesize that an approach capitalizing on the speed and catalytic nature of enzymatic reactions would enable fast and sensitive biomarker detection, suitable for PoCT devices. Methods and findings We performed in-vitro, animal model, and human subject studies. First, the efficiency of coupled enzyme activities when tethered to NPs versus when in solution was tested, demonstrating a highly sensitive and rapid detection of physiological and pathological concentrations of NSE. Next, in rat stroke models the enzyme-based assay was able in minutes to show a statistically significant increase in NSE levels in samples taken 1 hour before and 0, 1, 3 and 6 hours after occlusion of the distal middle cerebral artery. Finally, using the tethered enzyme assay for detection of NSE in samples from 20 geriatric human patients, we show that our data match well (r = 0.815) with the current gold standard for biomarker detection, ELISA—with a major difference being that we achieve detection in 10 minutes as opposed to the several hours required for traditional ELISA. Conclusions Oriented enzyme immobilization conferred more efficient coupled activity, and thus higher assay sensitivity, than non-tethered enzymes. Together, our findings provide proof of concept for using oriented immobilization of active enzymes on NPs as the basis for a highly rapid and sensitive biomarker detection platform. This addresses a key challenge in developing a PoCT platform for time sensitive and difficult to diagnose pathologies. PMID:26605916

The Calmodulin-Binding, Short Linear Motif, NSCaTE Is Conserved in L-Type Channel Ancestors of Vertebrate Cav1.2 and Cav1.3 Channels

PubMed Central

Taiakina, Valentina; Boone, Adrienne N.; Fux, Julia; Senatore, Adriano; Weber-Adrian, Danielle

2013-01-01

NSCaTE is a short linear motif of (xWxxx(I or L)xxxx), composed of residues with a high helix-forming propensity within a mostly disordered N-terminus that is conserved in L-type calcium channels from protostome invertebrates to humans. NSCaTE is an optional, lower affinity and calcium-sensitive binding site for calmodulin (CaM) which competes for CaM binding with a more ancient, C-terminal IQ domain on L-type channels. CaM bound to N- and C- terminal tails serve as dual detectors to changing intracellular Ca2+ concentrations, promoting calcium-dependent inactivation of L-type calcium channels. NSCaTE is absent in some arthropod species, and is also lacking in vertebrate L-type isoforms, Cav1.1 and Cav1.4 channels. The pervasiveness of a methionine just downstream from NSCaTE suggests that L-type channels could generate alternative N-termini lacking NSCaTE through the choice of translational start sites. Long N-terminus with an NSCaTE motif in L-type calcium channel homolog LCav1 from pond snail Lymnaea stagnalis has a faster calcium-dependent inactivation than a shortened N-termini lacking NSCaTE. NSCaTE effects are present in low concentrations of internal buffer (0.5 mM EGTA), but disappears in high buffer conditions (10 mM EGTA). Snail and mammalian NSCaTE have an alpha-helical propensity upon binding Ca2+-CaM and can saturate both CaM N-terminal and C-terminal domains in the absence of a competing IQ motif. NSCaTE evolved in ancestors of the first animals with internal organs for promoting a more rapid, calcium-sensitive inactivation of L-type channels. PMID:23626724

An immuno-wall microdevice exhibits rapid and sensitive detection of IDH1-R132H mutation specific to grade II and III gliomas

PubMed Central

Yamamichi, Akane; Kasama, Toshihiro; Ohka, Fumiharu; Suzuki, Hiromichi; Kato, Akira; Motomura, Kazuya; Hirano, Masaki; Ranjit, Melissa; Chalise, Lushun; Kurimoto, Michihiro; Kondo, Goro; Aoki, Kosuke; Kaji, Noritada; Tokeshi, Manabu; Matsubara, Toshio; Senga, Takeshi; Kaneko, Mika K.; Suzuki, Hidenori; Hara, Masahito; Wakabayashi, Toshihiko; Baba, Yoshinobu; Kato, Yukinari; Natsume, Atsushi

2016-01-01

Abstract World Health Organization grade II and III gliomas most frequently occur in the central nervous system (CNS) in adults. Gliomas are not circumscribed; tumor edges are irregular and consist of tumor cells, normal brain tissue, and hyperplastic reactive glial cells. Therefore, the tumors are not fully resectable, resulting in recurrence, malignant progression, and eventual death. Approximately 69–80% of grade II and III gliomas harbor mutations in the isocitrate dehydrogenase 1 gene (IDH1), of which 83–90% are found to be the IDH1-R132H mutation. Detection of the IDH1-R132H mutation should help in the differential diagnosis of grade II and III gliomas from other types of CNS tumors and help determine the boundary between the tumor and normal brain tissue. In this study, we established a highly sensitive antibody-based device, referred to as the immuno-wall, to detect the IDH1-R132H mutation in gliomas. The immuno-wall causes an immunoreaction in microchannels fabricated using a photo-polymerizing polymer. This microdevice enables the analysis of the IDH1 status with a small sample within 15 min with substantially high sensitivity. Our results suggested that 10% content of the IDH1-R132H mutation in a sample of 0.33 μl volume, with 500 ng protein, or from 500 cells is theoretically sufficient for the analysis. The immuno-wall device will enable the rapid and highly sensitive detection of the IDH1-R132H mutation in routine clinical practice. PMID:27877908

Diagnostic sensitivity and specificity of a participatory disease surveillance method for highly pathogenic avian influenza in household chicken flocks in Indonesia.

PubMed

Robyn, M; Priyono, W B; Kim, L M; Brum, E

2012-06-01

A study was conducted to assess the diagnostic sensitivity and specificity of a disease surveillance method for diagnosis of highly pathogenic avian influenza (HPAI) outbreaks in household chicken flocks used by participatory disease surveillance (PDS) teams in Yogyakarta Province, Indonesia. The Government of Indonesia, in partnership with the Food and Agriculture Organization of the United Nations, has implemented a PDS method for the detection of HPAI outbreaks in poultry since 2006. The PDS method in Indonesia utilizes both a clinical case definition (CD) and the result of a commercial rapid antigen test kit Yogyakarta 55611, to diagnose HPAI outbreaks, primarily in backyard chicken flocks. The following diagnostic sensitivities and specificities were obtained relative to real-time reverse transcription-PCR as the gold standard diagnostic test: 1) 89% sensitivity (CI95: 75%-97%) and 96% specificity (CI95: 89%-99%) for the PDS CD alone; 2) 86% sensitivity (CI95: 71%-95%) and 99% specificity (CI95: 94%-100%) for the rapid antigen test alone; and 3) 84% sensitivity (CI95: 68%-94%) and 100% specificity (CI95: 96%-100%) for the PDS CD result combined with the rapid antigen test result. Based on these results, HPAI outbreaks in extensively raised household chickens can be diagnosed with sufficient sensitivity and specificity using the PDS method as implemented in Indonesia. Subject to further field evaluation, data from this study suggest that the diagnostic sensitivity of the PDS method may be improved by expanding the PDS CD to include more possible clinical presentations of HPAI and by increasing the number of rapid antigen tests to three different birds with HPAI-compatible signs of same flock.

Spatial gene drives and pushed genetic waves.

PubMed

Tanaka, Hidenori; Stone, Howard A; Nelson, David R

2017-08-08

Gene drives have the potential to rapidly replace a harmful wild-type allele with a gene drive allele engineered to have desired functionalities. However, an accidental or premature release of a gene drive construct to the natural environment could damage an ecosystem irreversibly. Thus, it is important to understand the spatiotemporal consequences of the super-Mendelian population genetics before potential applications. Here, we use a reaction-diffusion model for sexually reproducing diploid organisms to study how a locally introduced gene drive allele spreads to replace the wild-type allele, although it possesses a selective disadvantage s > 0. Using methods developed by Barton and collaborators, we show that socially responsible gene drives require 0.5 < s < 0.697, a rather narrow range. In this "pushed wave" regime, the spatial spreading of gene drives will be initiated only when the initial frequency distribution is above a threshold profile called "critical propagule," which acts as a safeguard against accidental release. We also study how the spatial spread of the pushed wave can be stopped by making gene drives uniquely vulnerable ("sensitizing drive") in a way that is harmless for a wild-type allele. Finally, we show that appropriately sensitized drives in two dimensions can be stopped, even by imperfect barriers perforated by a series of gaps.

Spatial gene drives and pushed genetic waves

PubMed Central

Tanaka, Hidenori; Stone, Howard A.; Nelson, David R.

2017-01-01

Gene drives have the potential to rapidly replace a harmful wild-type allele with a gene drive allele engineered to have desired functionalities. However, an accidental or premature release of a gene drive construct to the natural environment could damage an ecosystem irreversibly. Thus, it is important to understand the spatiotemporal consequences of the super-Mendelian population genetics before potential applications. Here, we use a reaction–diffusion model for sexually reproducing diploid organisms to study how a locally introduced gene drive allele spreads to replace the wild-type allele, although it possesses a selective disadvantage s > 0. Using methods developed by Barton and collaborators, we show that socially responsible gene drives require 0.5 < s < 0.697, a rather narrow range. In this “pushed wave” regime, the spatial spreading of gene drives will be initiated only when the initial frequency distribution is above a threshold profile called “critical propagule,” which acts as a safeguard against accidental release. We also study how the spatial spread of the pushed wave can be stopped by making gene drives uniquely vulnerable (“sensitizing drive”) in a way that is harmless for a wild-type allele. Finally, we show that appropriately sensitized drives in two dimensions can be stopped, even by imperfect barriers perforated by a series of gaps. PMID:28743753

Loop-mediated isothermal amplification assay for rapid and sensitive detection of sheep pox and goat pox viruses in clinical samples.

PubMed

Venkatesan, G; Balamurugan, V; Bhanuprakash, V; Singh, R K; Pandey, A B

2016-06-01

A Loop-mediated isothermal amplification (LAMP) assay targeting the highly conserved DNA polymerase gene of capripox virus genome was developed and evaluated for rapid detection of sheep pox and goat pox viruses. The optimized LAMP assay is found specific and sensitive for amplification of target DNA with a diagnostic sensitivity and specificity of 96.6% and 100% respectively compared to quantitative PCR. The detection rate of LAMP, PCR and Q-PCR assays is found to be 81.5%, 67% and 83% respectively. This LAMP assay has the potential for rapid clinical diagnosis and surveillance of sheep pox and goat pox in field diagnostic laboratories. Copyright © 2016 Elsevier Ltd. All rights reserved.

Functional ion channels in human pulmonary artery smooth muscle cells: Voltage-dependent cation channels

PubMed Central

Firth, Amy L.; Remillard, Carmelle V.; Platoshyn, Oleksandr; Fantozzi, Ivana; Ko, Eun A.; Yuan, Jason X.-J.

2011-01-01

The activity of voltage-gated ion channels is critical for the maintenance of cellular membrane potential and generation of action potentials. In turn, membrane potential regulates cellular ion homeostasis, triggering the opening and closing of ion channels in the plasma membrane and, thus, enabling ion transport across the membrane. Such transmembrane ion fluxes are important for excitation–contraction coupling in pulmonary artery smooth muscle cells (PASMC). Families of voltage-dependent cation channels known to be present in PASMC include voltage-gated K+ (Kv) channels, voltage-dependent Ca2+-activated K+ (Kca) channels, L- and T- type voltage-dependent Ca2+ channels, voltage-gated Na+ channels and voltage-gated proton channels. When cells are dialyzed with Ca2+-free K+- solutions, depolarization elicits four components of 4-aminopyridine (4-AP)-sensitive Kvcurrents based on the kinetics of current activation and inactivation. In cell-attached membrane patches, depolarization elicits a wide range of single-channel K+ currents, with conductances ranging between 6 and 290 pS. Macroscopic 4-AP-sensitive Kv currents and iberiotoxin-sensitive Kca currents are also observed. Transcripts of (a) two Na+ channel α-subunit genes (SCN5A and SCN6A), (b) six Ca2+ channel α–subunit genes (α1A, α1B, α1X, α1D, α1Eand α1G) and many regulatory subunits (α2δ1, β1-4, and γ6), (c) 22 Kv channel α–subunit genes (Kv1.1 - Kv1.7, Kv1.10, Kv2.1, Kv3.1, Kv3.3, Kv3.4, Kv4.1, Kv4.2, Kv5.1, Kv 6.1-Kv6.3, Kv9.1, Kv9.3, Kv10.1 and Kv11.1) and three Kv channel β-subunit genes (Kvβ1-3) and (d) four Kca channel α–subunit genes (Sloα1 and SK2-SK4) and four Kca channel β-subunit genes (Kcaβ1-4) have been detected in PASMC. Tetrodotoxin-sensitive and rapidly inactivating Na+ currents have been recorded with properties similar to those in cardiac myocytes. In the presence of 20 mM external Ca2+, membrane depolarization from a holding potential of -100 mV elicits a rapidly inactivating T-type Ca2+ current, while depolarization from a holding potential of -70 mV elicits a slowly inactivating dihydropyridine-sensitive L-type Ca2+ current. This review will focus on describing the electrophysiological properties and molecular identities of these voltage-dependent cation channels in PASMC and their contribution to the regulation of pulmonary vascular function and its potential role in the pathogenesis of pulmonary vascular disease. PMID:21927714

Aspirin Desensitization in Patients With Coronary Artery Disease: Results of the Multicenter ADAPTED Registry (Aspirin Desensitization in Patients With Coronary Artery Disease).

PubMed

Rossini, Roberta; Iorio, Annamaria; Pozzi, Roberto; Bianco, Matteo; Musumeci, Giuseppe; Leonardi, Sergio; Lettieri, Corrado; Bossi, Irene; Colombo, Paola; Rigattieri, Stefano; Dossena, Cinzia; Anzuini, Angelo; Capodanno, Davide; Senni, Michele; Angiolillo, Dominick J

2017-02-01

There are limited data on aspirin (ASA) desensitization for patients with coronary artery disease. The aim of the present study was to assess the safety and efficacy of a standard rapid desensitization protocol in patients with ASA sensitivity undergoing coronary angiography. This is a prospective, multicenter, observational study including 7 Italian centers including patients with a history of ASA sensitivity undergoing coronary angiography with intent to undergo percutaneous coronary intervention. A total of 330 patients with history of ASA sensitivity with known/suspected stable coronary artery disease or presenting with an acute coronary syndrome, including ST-segment-elevation myocardial infarction were enrolled. Adverse effects to aspirin included urticaria (n=177, 53.6%), angioedema (n=69, 20.9%), asthma (n=65, 19.7%), and anaphylactic reaction (n=19, 5.8%). Among patients with urticaria/angioedema, 13 patients (3.9%) had a history of idiopathic chronic urticaria. All patients underwent a rapid ASA (5.5 hours) desensitization procedure. The desensitization procedure was performed before cardiac catheterization in all patients, except for those (n=78, 23.6%) presenting with ST-segment-elevation myocardial infarction who underwent the desensitization after primary percutaneous coronary intervention. Percutaneous coronary intervention was performed in 235 patients (71%) of the overall study population. The desensitization procedure was successful in 315 patients (95.4%) and in all patients with a history of anaphylactic reaction. Among the 15 patients (4.6%) who did not successfully respond to the desensitization protocol, adverse reactions were minor and responded to treatment with corticosteroids and antihistamines. Among patients with successful in-hospital ASA desensitization, 253 patients (80.3%) continued ASA for at least 12 months. Discontinuation of ASA in the 62 patients (19.7%) who had responded to the desensitization protocol was because of medical decision and not because of hypersensitivity reactions. A standard rapid desensitization protocol is safe and effective across a broad spectrum of patients, irrespective of the type of aspirin sensitivity manifestation, with indications to undergo coronary angiography with intent to perform percutaneous coronary intervention. URL: http://www.clinicaltrials.gov. Unique identifier: NCT02848339. © 2017 American Heart Association, Inc.

[Demand for and the Development of Detection Techniques for Source of Schistosome Infection in China].

PubMed

Wang, Shi-ping; He, Xin; Zhou, Yun-fei

2015-12-01

Schistosomiasis is a type of zoonotic parasitosis that severely impairs human health. Rapid detection of infection sources is a key to the control of schistosomiasis. With the effective control of schistosomiasis in China, the detection techniques for infection sources have also been developed. The rate and the intensity of infection among humans and livestocks have been significantly decreased in China, as the control program has entered the transmission control stage in most of the endemic areas. Under this situation, the traditional etiological diagnosing techniques and common immunological methods can not afford rapid detection of infection sources of schistosomiasis. Instead, we are calling for detection methods with higher sensitivity, specificity and stability while being less time-consuming, more convenient and less costing. In recent years, many improved or novel detection methods have been applied for the epidemiological surveillance of schistosomiasis, such as the automatic scanning microscopic image acquisition system, PCR-ELISA, immunosensors, loop-mediated isothermal amplification, etc. The development of new monitoring techniques can facilitate rapid detection of schistosome infection sources in endemic areas.

The performance of non-NAAT point-of-care (POC) tests and rapid NAAT tests for chlamydia and gonorrhoea infections. An assessment of currently available assays.

PubMed

Brook, Gary

2015-12-01

To identify point-of-care (POC) and rapid nucleic acid amplification techniques (NAATs) for the diagnosis of chlamydia and gonorrhoea and assess their utility. Literature search for available POC and rapid NAATs. The performance from the best-performing assays were applied hypothetically to patients in the clinic in which 100 consecutive patients with chlamydia and 100 with gonorrhoea were diagnosed in 1737 and 4575 patients respectively, with 44/100 and 54/100 treated at first attendance, respectively. 11 POC and 1 rapid NAAT were identified. Published performances for the best POC for chlamydia (CRT) were: sensitivity 41%-87%, specificity 89%-99.6%. Our data suggest that if this assay was used instead of our current NAAT, for every 100 patients diagnosed currently, 23-46 extra patients would be treated at first attendance; 10-35 would go undiagnosed with 7-191 false-positives. Best chlamydia rapid NAAT (GeneXpert): sensitivity 97.5%-98.7%, specificity 99.4%-99.9%. Anticipated performance for every 100 patients diagnosed currently: 0 extra patients treated at first attendance, 1-3 undiagnosed, 0-2 false-positives. Best POC for gonorrhoea (GC Check): sensitivity 54%-70%, specificity 97%-98%. Anticipated performance for every 100 patients diagnosed currently: 14-18 extra patients treated at first attendance, 28-32 undiagnosed, 92-137 false-positives. Best rapid NAAT for gonorrhoea (GeneXpert): sensitivity 96%-100%, specificity 99.9%-100%. Anticipated performance for every 100 patients diagnosed currently: 0 extra patients treated at first attendance, 0-4 undiagnosed, 0-5 false-positives. Rapid NAAT would reduce time to treatment by 4 days for initially untreated patients. POC assays would need to be used in conjunction with a NAAT, increasing early treatment rates expense and false-positive results. The rapid NAAT could be used alone, with a reduction in average time-to-treat and a small reduction in sensitivity and specificity. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

An analysis of the extension of a ZnO piezoelectric semiconductor nanofiber under an axial force

NASA Astrophysics Data System (ADS)

Zhang, Chunli; Wang, Xiaoyuan; Chen, Weiqiu; Yang, Jiashi

2017-02-01

This paper presents a theoretical analysis on the axial extension of an n-type ZnO piezoelectric semiconductor nanofiber under an axial force. The phenomenological theory of piezoelectric semiconductors consisting of Newton’s second law of motion, the charge equation of electrostatics and the conservation of charge was used. The equations were linearized for small axial force and hence small electron concentration perturbation, and were reduced to one-dimensional equations for thin fibers. Simple and analytical expressions for the electromechanical fields and electron concentration in the fiber were obtained. The fields are either totally or partially described by hyperbolic functions relatively large near the ends of the fiber and change rapidly there. The behavior of the fields is sensitive to the initial electron concentration and the applied axial force. For higher initial electron concentrations the fields are larger near the ends and change more rapidly there.

Quetiapine effective in treatment of inappropriate sexual behavior of lewy body disease with predominant frontal lobe signs.

PubMed

Prakash, Ravi; Pathak, Amit; Munda, Sanjay; Bagati, Dhruv

2009-01-01

Dementia of Lewy body disease is the second most common degenerative cause of dementia after Alzheimer's disease, among all the dementias. The core features are a progressive dementia, fluctuations in cognitive functions, visual hallucinations, and spontaneous parkinsonism. Rapid eye movement sleep behavior disorder, severe neuroleptic sensitivity, and low dopamine transporter uptake in basal ganglia are other suggestive features. Behavioral abnormalities are commonly present in the form of aggressive behavior, irritability, and uninhibited behaviors. These are mostly seen in the advanced stages of dementia. However, inappropriate sexual behavior is uncommonly seen in such cases. Three types of inappropriate sexual behaviors commonly found in cases of dementia are sex talks, sexual acts, and implied sexual acts. Such inappropriate sexual behaviors have not been described adequately in dementia of Lewy body disease. We report inappropriate sexual behaviors in a case of dementia of Lewy body disease, which improved rapidly after treatment with quetiapine.

Far-ultraviolet fluorescence of carbon monoxide in the red giant Arcturus. II - Analysis of high-dispersion IUE spectra

NASA Technical Reports Server (NTRS)

Ayres, T. R.

1986-01-01

Faint, diffuse emissions near 1380 A in deeply exposed IUE spectrograms of the red giant Arcturus very likely are associated with bands of the A-X fourth-positive system of carbon monoxide, fluoresced by multiplet UV2 of neutral oxygen near 1305 A. Numerical simulations indicate that the strength of the CO bands is exceedingly sensitive, in the best available one-dimensional model of the chromosphere of Arcturus, to a delicate balance between the rapid inward attenuation of the oxygen radiation field and the rapid outward decline of the molecular absorptivity. The fortuitous character of the overlap region in the single-component model argues that one should also consider the possibility that the pumping occurs in a highly inhomogeneous chromosphere, of the type proposed in previous studies of Arcturus based on observations of the infrared absorption bands of CO.

Digital detection of endonuclease mediated gene disruption in the HIV provirus

PubMed Central

Sedlak, Ruth Hall; Liang, Shu; Niyonzima, Nixon; De Silva Feelixge, Harshana S.; Roychoudhury, Pavitra; Greninger, Alexander L.; Weber, Nicholas D.; Boissel, Sandrine; Scharenberg, Andrew M.; Cheng, Anqi; Magaret, Amalia; Bumgarner, Roger; Stone, Daniel; Jerome, Keith R.

2016-01-01

Genome editing by designer nucleases is a rapidly evolving technology utilized in a highly diverse set of research fields. Among all fields, the T7 endonuclease mismatch cleavage assay, or Surveyor assay, is the most commonly used tool to assess genomic editing by designer nucleases. This assay, while relatively easy to perform, provides only a semi-quantitative measure of mutation efficiency that lacks sensitivity and accuracy. We demonstrate a simple droplet digital PCR assay that quickly quantitates a range of indel mutations with detection as low as 0.02% mutant in a wild type background and precision (≤6%CV) and accuracy superior to either mismatch cleavage assay or clonal sequencing when compared to next-generation sequencing. The precision and simplicity of this assay will facilitate comparison of gene editing approaches and their optimization, accelerating progress in this rapidly-moving field. PMID:26829887

Canine parvovirus 2c infection in central Portugal.

PubMed

João Vieira, Maria; Silva, Eliane; Oliveira, João; Luísa Vieira, Ana; Decaro, Nicola; Desario, Costantina; Muller, Alexandra; Carvalheira, Júlio; Buonavoglia, Canio; Thompson, Gertrude

2008-07-01

Canine parvovirus (CPV) has been evolving, generating new genetic and antigenic variants throughout the world. This study was conducted to determine the types of CPV circulating in dogs in Figueira da Foz, Portugal. Thirty fecal samples, collected between 2006 and 2007 from dogs with clinical signs of CPV infection, were tested for CPV by a rapid, in-clinic, enzyme-linked immunosorbent assay (ELISA)/immunomigration test, by conventional real-time polymerase chain reaction (PCR), and by minor-groove binding TaqMan PCR. Of the 29 PCR-positive samples, 15 were identified as CPV-2b and 14 as CPV-2c. No CPV-2a was detected. The sensitivity of the ELISA test was 82.76% compared with the PCR assays. No significant associations were found between CPV type, clinical outcome, breed, vaccination status, or age.

Numerical simulation of boundary layers. Part 2: Ribbon-induced transition in Blasius flow

NASA Technical Reports Server (NTRS)

Spalart, P.; Yang, K. S.

1986-01-01

The early three-dimensional stages of transition in Blasius boundary layers are studied by numerical solution of the Navier-Stokes equations. A finite-amplitude two-dimensional wave and random low-amplitude three-dimensional disturbances are introduced. Rapid amplification of the three-dimensional components is observed and leads to transition. For intermediate amplitudes of the two-dimensional wave the breakdown is of subharmonic type, and the dominant spanwise wave number increases with the amplitude. For high amplitudes the energy of the fundamental mode is comparable to the energy of the subharmonic mode, but never dominates it; the breakdown is of mixed type. Visualizations, energy histories, and spectra are presented. The sensitivity of the results to various physical and numerical parameters is studied. Agreement with experimental and theoretical results is discussed.

Spatial and temporal processing in healthy aging: implications for perceptions of driving skills.

PubMed

Conlon, Elizabeth; Herkes, Kathleen

2008-07-01

Sensitivity to the attributes of a stimulus (form or motion) and accuracy when detecting rapidly presented stimulus information were measured in older (N = 36) and younger (N = 37) groups. Before and after practice, the older group was significantly less sensitive to global motion (but not to form) and less accurate on a rapid sequencing task when detecting the individual elements presented in long but not short sequences. These effect sizes produced power for the different analyses that ranged between 0.5 and 1.00. The reduced sensitivity found among older individuals to temporal but not spatial stimuli, adds support to previous findings of a selective age-related deficit in temporal processing. Older women were significantly less sensitive than older men, younger men and younger women on the global motion task. Gender effects were evident when, in response to global motion stimuli, complex extraction and integration processes needed to be undertaken rapidly. Significant moderate correlations were found between age, global motion sensitivity and reports of perceptions of other vehicles and road signs when driving. These associations suggest that reduced motion sensitivity may produce functional difficulties for the older adults when judging speeds or estimating gaps in traffic while driving.

Wild poliovirus type 1 and type 3 importations--15 countries, Africa, 2008-2009.

PubMed

2009-04-17

The Global Polio Eradication Initiative began in 1988; by 2006, indigenous transmission of wild poliovirus (WPV) type 2 infection had been interrupted globally, and indigenous transmission of type 1 and 3 (WPV1 and WPV3) infection had been interrupted in all but four countries worldwide (Afghanistan, India, Nigeria, and Pakistan). Despite this success in controlling indigenous transmission, during 2002-2006, 20 previously polio-free countries in Africa and Asia had importations of WPV1 originating from Nigeria, and three polio-free countries in Africa had WPV1 importations originating from India. By the end of 2007, control efforts in all countries except Angola, Chad, Democratic Republic of the Congo (DRC), Niger, and Sudan had stopped transmission of WPV1 caused by these importations. However, during 2008-2009, multiple importations of WPV from countries with ongoing transmission resumed in Africa. This report describes 32 WPV importations into 15 African countries, resulting in 96 polio cases during January 2008-March 2009 and persistent WPV transmission in five previously polio-free African countries. As with the 2002-2006 resurgence, all of the importations originated from Nigeria or India, but more rapid WPV identification and response resulted in substantially fewer polio cases than reported during 2002-2006. Sensitive surveillance and continued rapid response supplemental immunization activities (SIAs) are key to limiting further WPV spread, interrupting the outbreaks, and allowing the polio prevention focus in Africa to return to eradicating polio in countries with persistent WPV transmission.

Photoacoustic tomography using a Michelson interferometer with quadrature phase detection

NASA Astrophysics Data System (ADS)

Speirs, Rory W.; Bishop, Alexis I.

2013-07-01

We present a pressure sensor based on a Michelson interferometer, for use in photoacoustic tomography. Quadrature phase detection is employed allowing measurement at any point on the mirror surface without having to retune the interferometer, as is typically required by Fabry-Perot type detectors. This opens the door to rapid full surface detection, which is necessary for clinical applications. Theory relating acoustic pressure to detected acoustic particle displacements is used to calculate the detector sensitivity, which is validated with measurement. Proof-of-concept tomographic images of blood vessel phantoms have been taken with sub-millimeter resolution at depths of several millimeters.

Raman Spectroscopy of Microbial Pigments

PubMed Central

Edwards, Howell G. M.; Oren, Aharon

2014-01-01

Raman spectroscopy is a rapid nondestructive technique providing spectroscopic and structural information on both organic and inorganic molecular compounds. Extensive applications for the method in the characterization of pigments have been found. Due to the high sensitivity of Raman spectroscopy for the detection of chlorophylls, carotenoids, scytonemin, and a range of other pigments found in the microbial world, it is an excellent technique to monitor the presence of such pigments, both in pure cultures and in environmental samples. Miniaturized portable handheld instruments are available; these instruments can be used to detect pigments in microbiological samples of different types and origins under field conditions. PMID:24682303

Highly sensitive detection of human papillomavirus type 16 DNA using time-resolved fluorescence microscopy and long lifetime probes

NASA Astrophysics Data System (ADS)

Wang, Xue F.; Periasamy, Ammasi; Wodnicki, Pawel; Siadat-Pajouh, M.; Herman, Brian

1995-04-01

We have been interested in the role of Human Papillomavirus (HPV) in cervical cancer and its diagnosis; to that end we have been developing microscopic imaging and fluorescent in situ hybridization (FISH) techniques to genotype and quantitate the amount of HPV present at a single cell level in cervical PAP smears. However, we have found that low levels of HPV DNA are difficult to detect accurately because theoretically obtainable sensitivity is never achieved due to nonspecific autofluorescence, fixative induced fluorescence of cells and tissues, and autofluorescence of the optical components in the microscopic system. In addition, the absorption stains used for PAP smears are intensely autofluorescent. Autofluorescence is a rapidly decaying process with lifetimes in the range of 1-100 nsec, whereas phosphorescence and delayed fluorescence have lifetimes in the range of 1 microsecond(s) ec-10 msec. The ability to discriminate between specific fluorescence and autofluorescence in the time-domain has improved the sensitivity of diagnostic test such that they perform comparably to, or even more sensitive than radioisotopic assays. We have developed a novel time-resolved fluorescence microscope to improve the sensitivity of detection of specific molecules of interest in slide based specimens. This time-resolved fluorescence microscope is based on our recently developed fluorescence lifetime imaging microscopy (FILM) in conjunction with the use of long lifetime fluorescent labels. By using fluorescence in situ hybridization and the long lifetime probe (europium), we have demonstrated the utility of this technique for detection of HPV DNA in cervicovaginal cells. Our results indicate that the use of time-resolved fluorescence microscopy and long lifetime probes increases the sensitivity of detection by removing autofluorescence and will thus lead to improved early diagnosis of cervical cancer. Since the highly sensitive detection of DNA in clinical samples using fluorescence in situ hybridization image is useful for the diagnosis of many other type of diseases, the system we have developed should find numerous applications for the diagnosis of disease states.

Enhanced detection of type C botulinum neurotoxin by the Endopep-MS assay through optimization of peptide substrates

PubMed Central

Wang, Dongxia; Krilich, Joan; Baudys, Jakub; Barr, John R.; Kalb, Suzanne R.

2015-01-01

It is essential to have a simple, quick and sensitive method for the detection and quantification of botulinum neurotoxins, the most toxic substances and the causative agents of botulism. Type C botulinum neurotoxin (BoNT/C) represents one of the seven members of distinctive BoNT serotypes (A to G) that cause botulism in animals and avians. Here we report the development of optimized peptide substrates for improving the detection of BoNT/C and /CD mosaic toxins using an Endopep-MS assay, a mass spectrometry-based method that is able to rapidly and sensitively detect and differentiate all types of BoNTs by extracting the toxin with specific antibodies and detecting the unique cleavage products of peptide substrates. Based on the sequence of a short SNAP-25 peptide, we conducted optimization through a comprehensive process including length determination, terminal modification, single and multiple amino acid residue substitution, and incorporation of unnatural amino acid residues. Our data demonstrate that an optimal peptide provides a more than 200-fold improvement over the substrate currently used in the Endopep-MS assay for the detection of BoNT/C1 and /CD mosaic. Using the new substrate in a four-hour cleavage reaction, the limit of detection for the BoNT/C1 complex spiked in buffer, serum and milk samples was determined to be 0.5, 0.5 and 1 mouseLD50/mL, respectively, representing a similar or higher sensitivity than that obtained by traditional mouse bioassay. PMID:25913863

Nucleophile sensitivity of Drosophila TRPA1 underlies light-induced feeding deterrence

PubMed Central

Du, Eun Jo; Ahn, Tae Jung; Wen, Xianlan; Seo, Dae-Won; Na, Duk L; Kwon, Jae Young; Choi, Myunghwan; Kim, Hyung-Wook; Cho, Hana; Kang, KyeongJin

2016-01-01

Solar irradiation including ultraviolet (UV) light causes tissue damage by generating reactive free radicals that can be electrophilic or nucleophilic due to unpaired electrons. Little is known about how free radicals induced by natural sunlight are rapidly detected and avoided by animals. We discover that Drosophila Transient Receptor Potential Ankyrin 1 (TRPA1), previously known only as an electrophile receptor, sensitively detects photochemically active sunlight through nucleophile sensitivity. Rapid light-dependent feeding deterrence in Drosophila was mediated only by the TRPA1(A) isoform, despite the TRPA1(A) and TRPA1(B) isoforms having similar electrophile sensitivities. Such isoform dependence re-emerges in the detection of structurally varied nucleophilic compounds and nucleophilicity-accompanying hydrogen peroxide (H2O2). Furthermore, these isoform-dependent mechanisms require a common set of TRPA1(A)-specific residues dispensable for electrophile detection. Collectively, TRPA1(A) rapidly responds to natural sunlight intensities through its nucleophile sensitivity as a receptor of photochemically generated radicals, leading to an acute light-induced behavioral shift in Drosophila. DOI: http://dx.doi.org/10.7554/eLife.18425.001 PMID:27656903

A highly sensitive and specific capacitive aptasensor for rapid and label-free trace analysis of Bisphenol A (BPA) in canned foods.

PubMed

Mirzajani, Hadi; Cheng, Cheng; Wu, Jayne; Chen, Jiangang; Eda, Shigotoshi; Najafi Aghdam, Esmaeil; Badri Ghavifekr, Habib

2017-03-15

A rapid, highly sensitive, specific and low-cost capacitive affinity biosensor is presented here for label-free and single step detection of Bisphenol A (BPA). The sensor design allows rapid prototyping at low-cost using printed circuit board material by benchtop equipment. High sensitivity detection is achieved through the use of a BPA-specific aptamer as probe molecule and large electrodes to enhance AC-electroelectrothermal effect for long-range transport of BPA molecules toward electrode surface. Capacitive sensing technique is used to determine the bounded BPA level by measuring the sample/electrode interfacial capacitance of the sensor. The developed biosensor can detect BPA level in 20s and exhibits a large linear range from 1 fM to 10 pM, with a limit of detection (LOD) of 152.93 aM. This biosensor was applied to test BPA in canned food samples and could successfully recover the levels of spiked BPA. This sensor technology is demonstrated to be highly promising and reliable for rapid, sensitive and on-site monitoring of BPA in food samples. Copyright © 2016 Elsevier B.V. All rights reserved.

Rapid-scan Fourier-transform coherent anti-Stokes Raman scattering spectroscopy with heterodyne detection.

PubMed

Hiramatsu, Kotaro; Luo, Yizhi; Ideguchi, Takuro; Goda, Keisuke

2017-11-01

High-speed Raman spectroscopy has become increasingly important for analyzing chemical dynamics in real time. To address the need, rapid-scan Fourier-transform coherent anti-Stokes Raman scattering (FT-CARS) spectroscopy has been developed to realize broadband CARS measurements at a scan rate of more than 20,000 scans/s. However, the detection sensitivity of FT-CARS spectroscopy is inherently low due to the limited number of photons detected during each scan. In this Letter, we show our experimental demonstration of enhanced sensitivity in rapid-scan FT-CARS spectroscopy by heterodyne detection. Specifically, we implemented heterodyne detection by superposing the CARS electric field with an external local oscillator (LO) for their interference. The CARS signal was amplified by simply increasing the power of the LO without the need for increasing the incident power onto the sample. Consequently, we achieved enhancement in signal intensity and the signal-to-noise ratio by factors of 39 and 5, respectively, compared to FT-CARS spectroscopy with homodyne detection. The sensitivity-improved rapid-scan FT-CARS spectroscopy is expected to enable the sensitive real-time observation of chemical dynamics in a broad range of settings, such as combustion engines and live biological cells.

Rapid, ultrasensitive detection of microorganisms based on interferometry and lab-on-a-chip nanotechnology

NASA Astrophysics Data System (ADS)

Ymeti, Aurel; Nederkoorn, Paul H. J.; Dudia, Alma; Subramaniam, Vinod; Kanger, Johannes S.

2009-05-01

Future viral outbreaks are a major threat to societal and economic development throughout the world. A rapid, sensitive, and easy-to-use test for viral infections is essential to prevent and to control such viral pandemics. Furthermore, a compact, portable device is potentially very useful in remote or developing regions without easy access to sophisticated laboratory facilities. We have developed a rapid, ultrasensitive sensor that could be used in a handheld device to detect various viruses and measure their concentration. The essential innovation in this technique is the combination of an integrated optical interferometric sensor with antibody-antigen recognition approaches to yield a very sensitive, very rapid test for virus detection. The sensor is able to spot the herpes virus at concentrations of just 850 particles per milliliter under physiological conditions. The sensitivity of the sensor approaches detection of a single virus particle, yielding a sensor of unprecedented sensitivity with wide applications for viral diagnostics. The sensor's detection principle can be extended to any biological target such as bacteria, cells and proteins and for which there are specific antibodies. The nature of the sensor enables multiplexed detection of several analytes at the same time.

A novel ultra-performance liquid chromatography hyphenated with quadrupole time of flight mass spectrometry method for rapid estimation of total toxic retronecine-type of pyrrolizidine alkaloids in herbs without requiring corresponding standards.

PubMed

Zhu, Lin; Ruan, Jian-Qing; Li, Na; Fu, Peter P; Ye, Yang; Lin, Ge

2016-03-01

Nearly 50% of naturally-occurring pyrrolizidine alkaloids (PAs) are hepatotoxic, and the majority of hepatotoxic PAs are retronecine-type PAs (RET-PAs). However, quantitative measurement of PAs in herbs/foodstuffs is often difficult because most of reference PAs are unavailable. In this study, a rapid, selective, and sensitive UHPLC-QTOF-MS method was developed for the estimation of RET-PAs in herbs without requiring corresponding standards. This method is based on our previously established characteristic and diagnostic mass fragmentation patterns and the use of retrorsine for calibration. The use of a single RET-PA (i.e. retrorsine) for construction of calibration was based on high similarities with no significant differences demonstrated by the calibration curves constructed by peak areas of extract ion chromatograms of fragment ion at m/z 120.0813 or 138.0919 versus concentrations of five representative RET-PAs. The developed method was successfully applied to measure a total content of toxic RET-PAs of diversified structures in fifteen potential PA-containing herbs. Copyright © 2014 Elsevier Ltd. All rights reserved.

Evaluation of rapid readout biological indicators for 132 degrees C gravity and 132 degrees C vacuum-assisted steam sterilization cycles using a new automated fluorescent reader.

PubMed

Alfa, Michelle J; Olson, Nancy; DeGagne, Pat; Jackson, Michele

2002-07-01

The primary objective of this study was to evaluate fluorescent readout results of Attest 1291 Biological Indicators (BIs) (3M Health Care, St. Paul, MN) and Attest 1296 BI test packs (containing Attest 1292 BIs) using full and fractional cycles compared with the growth data when prolonged incubation (7 days) was included. Gravity displacement and vacuum-assisted steam sterilization cycles were evaluated. A secondary objective of this study was to evaluate the new automated rapid fluorescent reader (Attest 290 Auto Reader). The rapid readout BIs for gravity displacement and vacuum-assisted steam autoclave cycles at 132 degrees C were processed using full (4 minutes) and four fractional cycles that provided 30% to 80% positive results for growth after 24 hours of incubation (48 hours of incubation for Attest 1292 BIs from the Attest 1296 test packs). Sixty of each type of BI were tested for each cycle (300 of each BI type in total). For all full steam sterilization cycles, results of the rapid fluorescent readout and the 24-hour, 48-hour, and 7-day growth tests were negative for all Attest 1291 and 1292 BIs tested. For all fractional cycles, the 24- and 48-hour growth results for the Attest 1291 and 1292 BIs, respectively, were the same as the 7-day growth results. The fractional cycle data indicated that fluorescent rapid readout was a more sensitive indicator than growth. There were rare (0.9%) false-negative results for BIs under fractional cycle conditions and these all correlated with short fractional cycle exposure times. The fluorescent rapid readout results of the 1291 BIs and 1296 BI test packs reliably predict both 24- and 48-hour and 7-day growth. These data support the value of rapid readout BIs for sterilizer monitoring for both the vacuum-assisted and the gravity displacement steam sterilization cycles. The new automated reader requires less manipulation of the BI and makes monitoring user friendly and less prone to user errors.

Efficient Inversion of Mult-frequency and Multi-Source Electromagnetic Data

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

Gary D. Egbert

2007-03-22

The project covered by this report focused on development of efficient but robust non-linear inversion algorithms for electromagnetic induction data, in particular for data collected with multiple receivers, and multiple transmitters, a situation extremely common in eophysical EM subsurface imaging methods. A key observation is that for such multi-transmitter problems each step in commonly used linearized iterative limited memory search schemes such as conjugate gradients (CG) requires solution of forward and adjoint EM problems for each of the N frequencies or sources, essentially generating data sensitivities for an N dimensional data-subspace. These multiple sensitivities allow a good approximation to themore » full Jacobian of the data mapping to be built up in many fewer search steps than would be required by application of textbook optimization methods, which take no account of the multiplicity of forward problems that must be solved for each search step. We have applied this idea to a develop a hybrid inversion scheme that combines features of the iterative limited memory type methods with a Newton-type approach using a partial calculation of the Jacobian. Initial tests on 2D problems show that the new approach produces results essentially identical to a Newton type Occam minimum structure inversion, while running more rapidly than an iterative (fixed regularization parameter) CG style inversion. Memory requirements, while greater than for something like CG, are modest enough that even in 3D the scheme should allow 3D inverse problems to be solved on a common desktop PC, at least for modest (~ 100 sites, 15-20 frequencies) data sets. A secondary focus of the research has been development of a modular system for EM inversion, using an object oriented approach. This system has proven useful for more rapid prototyping of inversion algorithms, in particular allowing initial development and testing to be conducted with two-dimensional example problems, before approaching more computationally cumbersome three-dimensional problems.« less

Disposable bioluminescence-based biosensor for detection of bacterial count in food.

PubMed

Luo, Jinping; Liu, Xiaohong; Tian, Qing; Yue, Weiwei; Zeng, Jing; Chen, Guangquan; Cai, Xinxia

2009-11-01

A biosensor for rapid detection of bacterial count based on adenosine 5'-triphosphate (ATP) bioluminescence has been developed. The biosensor is composed of a key sensitive element and a photomultiplier tube used as a detector element. The disposable sensitive element consists of a sampler, a cartridge where intracellular ATP is chemically extracted from bacteria, and a microtube where the extracted ATP reacts with the luciferin-luciferase reagent to produce bioluminescence. The bioluminescence signal is transformed into relevant electrical signal by the detector and further measured with a homemade luminometer. Parameters affecting the amount of the extracted ATP, including the types of ATP extractants, the concentrations of ATP extractant, and the relevant neutralizing reagent, were optimized. Under the optimal experimental conditions, the biosensor showed a linear response to standard bacteria in a concentration range from 10(3) to 10(8) colony-forming units (CFU) per milliliter with a correlation coefficient of 0.925 (n=22) within 5min. Moreover, the bacterial count of real food samples obtained by the biosensor correlated well with those by the conventional plate count method. The proposed biosensor, with characteristics of low cost, easy operation, and fast response, provides potential application to rapid evaluation of bacterial contamination in the food industry, environment monitoring, and other fields.

Simultaneous determination of water-soluble vitamins in selected food matrices by liquid chromatography/electrospray ionization tandem mass spectrometry.

PubMed

Gentili, Alessandra; Caretti, Fulvia; D'Ascenzo, Giuseppe; Marchese, Stefano; Perret, Daniela; Di Corcia, Daniele; Rocca, Lucia Mainero

2008-07-01

A rapid, simple and sensitive method based on liquid chromatography/tandem mass spectrometry (LC/MS/MS) with an electrospray ionization (ESI) source for the simultaneous analysis of fourteen water-soluble vitamins (B1, B2, two B3 vitamers, B5, five B6 vitamers, B8, B9, B12 and C) in various food matrices, i.e. maize flour, green and golden kiwi and tomato pulp, is presented here. Analytes were separated by ion-suppression reversed-phase liquid chromatography in less than 10 min and detected in positive ion mode. Sensitivity and specificity of this method allowed two important results to be achieved: (i) limits of detection of the analytes at ng g(-1) levels (except for vitamin C); (ii) development of a rapid sample treatment that minimizes analyte exposition to light, air and heat, eliminating any step of extract concentration. Analyte recovery depended on the type of matrix. In particular, recovery of the analytes in maize flour was > or =70%, with the exception of vitamin C, pyridoxal-5'-phosphate and vitamin B9 (ca 40%); with tomato pulp, recovery was > or =64%, except for vitamin C (41%); with kiwi, recovery was > or =73%, except for nicotinamide (ca. 30%).

Study on validity of a rapid diagnostic test kit versus light microscopy for malaria diagnosis in Ahmedabad city, India.

PubMed

Vyas, S; Puwar, B; Patel, V; Bhatt, G; Kulkarni, S; Fancy, M

2014-05-01

Light microscopy of blood smears for diagnosis of malaria in the field has several limitations, notably delays in diagnosis. This study in Ahmedabad in Gujarat State, India, evaluated the diagnostic performance of a rapid diagnostic test for malaria (SD Bioline Malaria Ag P.f/Pan) versus blood smear examination as the gold standard. All fever cases presenting at 13 urban health centres were subjected to rapid diagnostic testing and thick and thin blood smears. A total of 677 cases with fever were examined; 135 (20.0%) tested positive by rapid diagnostic test and 86 (12.7%) by blood smear. The sensitivity of the rapid diagnostic test for malaria was 98.8%, specificity was 91.5%, positive predictive value 63.0% and negative predictive value 99.8%. For detection of Plasmodium falciparum the sensitivity of rapid diagnostic test was 100% and specificity was 97.3%. The results show the acceptability of the rapid test as an alternative to light microscopy in the field setting.

Rapid detection of Enterovirus and Coxsackievirus A10 by a TaqMan based duplex one-step real time RT-PCR assay.

PubMed

Chen, Jingfang; Zhang, Rusheng; Ou, Xinhua; Yao, Dong; Huang, Zheng; Li, Linzhi; Sun, Biancheng

2017-06-01

A TaqMan based duplex one-step real time RT-PCR (rRT-PCR) assay was developed for the rapid detection of Coxsackievirus A10 (CV-A10) and other enterovirus (EVs) in clinical samples. The assay was fully evaluated and found to be specific and sensitive. When applied in 115 clinical samples, a 100% diagnostic sensitivity in CV-A10 detection and 97.4% diagnostic sensitivity in other EVs were found. Copyright © 2017 Elsevier Ltd. All rights reserved.

Light-induced phosphorylation of a membrane protein plays an early role in signal transduction for phototropism in Arabidopsis thaliana

NASA Technical Reports Server (NTRS)

Reymond, P.; Short, T. W.; Briggs, W. R.; Poff, K. L.

1992-01-01

Blue light is known to cause rapid phosphorylation of a membrane protein in etiolated seedlings of several plant species, a protein that, at least in etiolated pea seedlings and maize coleoptiles, has been shown to be associated with the plasma membrane. The light-driven phosphorylation has been proposed on the basis of correlative evidence to be an early step in the signal transduction chain for phototropism. In the Arabidopsis thaliana mutant JK224, the sensitivity to blue light for induction of first positive phototropism is known to be 20- to 30-fold lower than in wild type, whereas second positive curvature appears to be normal. While light-induced phosphorylation can be demonstrated in crude membrane preparations from shoots of the mutant, the level of phosphorylation is dramatically lower than in wild type, as is the sensitivity to blue light. Another A. thaliana mutant, JK218, that completely lacks any phototropic responses to up to 2 h of irradiation, shows a normal level of light-induced phosphorylation at saturation. Since its gravitropic sensitivity is normal, it is presumably blocked in some step between photoreception and the confluence of the signal transduction pathways for phototropism and gravitropism. We conclude from mutant JK224 that light-induced phosphorylation plays an early role in the signal transduction chain for phototropism in higher plants.

Field Demonstration of a Multiplexed Point-of-Care Diagnostic Platform for Plant Pathogens.

PubMed

Lau, Han Yih; Wang, Yuling; Wee, Eugene J H; Botella, Jose R; Trau, Matt

2016-08-16

Effective disease management strategies to prevent catastrophic crop losses require rapid, sensitive, and multiplexed detection methods for timely decision making. To address this need, a rapid, highly specific and sensitive point-of-care method for multiplex detection of plant pathogens was developed by taking advantage of surface-enhanced Raman scattering (SERS) labeled nanotags and recombinase polymerase amplification (RPA), which is a rapid isothermal amplification method with high specificity. In this study, three agriculturally important plant pathogens (Botrytis cinerea, Pseudomonas syringae, and Fusarium oxysporum) were used to demonstrate potential translation into the field. The RPA-SERS method was faster, more sensitive than polymerase chain reaction, and could detect as little as 2 copies of B. cinerea DNA. Furthermore, multiplex detection of the three pathogens was demonstrated for complex systems such as the Arabidopsis thaliana plant and commercial tomato crops. To demonstrate the potential for on-site field applications, a rapid single-tube RPA/SERS assay was further developed and successfully performed for a specific target outside of a laboratory setting.

Reliability of rapid reporting of cancers in New Hampshire.

PubMed

Celaya, Maria O; Riddle, Bruce L; Cherala, Sai S; Armenti, Karla R; Rees, Judy R

2010-01-01

The New Hampshire State Cancer Registry (NHSCR) has a 2-phase reporting system. An abbreviated, "rapid" report of cancer diagnosis or treatment is due to the central registry within 45 days of diagnosis and a more detailed, definitive report is due within 180 days. Rapid reports are used for various research studies, but researchers who contact patients are warned that the rapid reports may contain inaccuracies. This study aimed to assess the reliability of rapid cancer reports. For diagnosis years 2000-2004, we compared the rapid and definitive reports submitted to NHSCR. We calculated the sensitivity and positive predictive value of rapid reports; the reliability of key data items overall and for major sites; and the time between diagnosis and submission of the report. Rapid reports identified incident cancer cases with a sensitivity of 88.5%. The overall accuracy of key data items was high. The accuracy of primary sites identified by rapid reports was high generally but lower for ovarian and unknown primaries. A subset analysis showed that 47% of cancers were reported within 90 days of diagnosis. Rapid reports submitted to NHSCR are generally of high quality and present a useful opportunity for research investigations in New Hampshire.

ELECTRICAL STUDIES ON THE COMPOUND EYE OF LIGIA OCCIDENTALIS DANA (CRUSTACEA: ISOPODA)

PubMed Central

Ruck, Philip; Jahn, Theodore L.

1954-01-01

The ERG of the compound eye in freshly collected Ligia occidentalis, in response to high intensity light flashes of ⅛ second or longer duration, begins with a negative on-effect quickly followed by an early positive deflection, rapidly returns to the baseline during illumination, and ends with a positive off-effect. As the stimulus intensity is decreased the early positivity progressively decreases and the rapid return to the baseline is replaced by a slowing decline of the negative on-effect. Responses were recorded with one active electrode subcorneally situated in the illuminated eye, the reference electrode in the dark eye. The dark-adapted eye shows a facilitation of the amplitude and rates of rise and fall of the on-effect to a brief, high intensity light stimulus. This facilitation may persist for more than 2 minutes. Following light adaptation under conditions in which the human eye loses sensitivity by a factor of almost 40,000 the Ligia eye loses sensitivity by a factor of only 3. The flicker fusion frequency of the ERG may be as high as 120/second with a corneal illumination of 15,000 foot-candles. Bleeding an otherwise intact animal very rapidly results in a decline of amplitude, change of wave form, and loss of facilitation in the ERG. When the eye is deganglionated without bleeding the animal the isolated retina responds in the same manner as the intact eye. Histological examination of the Ligia receptor layer showed that each ommatidium contains three different retinula cell types, each of which may be responsible for a different aspect of the ERG. PMID:13174786

Effectiveness of a Rapid Lumbar Spine MRI Protocol Using 3D T2-Weighted SPACE Imaging Versus a Standard Protocol for Evaluation of Degenerative Changes of the Lumbar Spine.

PubMed

Sayah, Anousheh; Jay, Ann K; Toaff, Jacob S; Makariou, Erini V; Berkowitz, Frank

2016-09-01

Reducing lumbar spine MRI scanning time while retaining diagnostic accuracy can benefit patients and reduce health care costs. This study compares the effectiveness of a rapid lumbar MRI protocol using 3D T2-weighted sampling perfection with application-optimized contrast with different flip-angle evolutions (SPACE) sequences with a standard MRI protocol for evaluation of lumbar spondylosis. Two hundred fifty consecutive unenhanced lumbar MRI examinations performed at 1.5 T were retrospectively reviewed. Full, rapid, and complete versions of each examination were interpreted for spondylotic changes at each lumbar level, including herniations and neural compromise. The full examination consisted of sagittal T1-weighted, T2-weighted turbo spin-echo (TSE), and STIR sequences; and axial T1- and T2-weighted TSE sequences (time, 18 minutes 40 seconds). The rapid examination consisted of sagittal T1- and T2-weighted SPACE sequences, with axial SPACE reformations (time, 8 minutes 46 seconds). The complete examination consisted of the full examination plus the T2-weighted SPACE sequence. Sensitivities and specificities of the full and rapid examinations were calculated using the complete study as the reference standard. The rapid and full studies had sensitivities of 76.0% and 69.3%, with specificities of 97.2% and 97.9%, respectively, for all degenerative processes. Rapid and full sensitivities were 68.7% and 66.3% for disk herniation, 85.2% and 81.5% for canal compromise, 82.9% and 69.1% for lateral recess compromise, and 76.9% and 69.7% for foraminal compromise, respectively. Isotropic SPACE T2-weighted imaging provides high-quality imaging of lumbar spondylosis, with multiplanar reformatting capability. Our SPACE-based rapid protocol had sensitivities and specificities for herniations and neural compromise comparable to those of the protocol without SPACE. This protocol fits within a 15-minute slot, potentially reducing costs and discomfort for a large subgroup of patients.

[Performance of Cholera-SMART and Pathogen-Detection-Kit in the quick diagnosis of cholera].

PubMed

Bolaños, Hilda María; Acuña, María Teresa; Serrano, Ana María; Obando, Xinia; Mairena, Hazel; Cháves, Lorena; Sandí, Flor; Rodríguez, Gina; Tamplin, Mark L; Pérez, Enrique; Campos, Elena

2004-10-01

To compare the performance of two rapid systems for the diagnosis of cholera with the culture method, and to propose a strategy for improving the specificity and sensitivity of these systems and reducing the costs involved in making a diagnosis. The following institutions participated in the study: the National Bacteriology Referral Center (Centro Nacional de Referencia en Bacteriologia, CNRB) of the Costa Rican Institute for Research and Teaching in Nutrition and Health (Instituto Costarricense de Investigacion y Ensenanza en Nutricion y Salud, INCIENSA) and various hospitals in the provinces of Alajuela, Guanacaste and San Jose, in Costa Rica. A total of 237 feces samples were used to asses the performance of two tests for the rapid detection of Vibrio cholerae 01: the Pathogen Detection Kit (PDK, Intelligent Monitoring Systems, Gainesville, Florida, USA) and Cholera-SMART (New Horizons Diagnostics Corp., Columbia, Maryland, USA), both when applied directly (direct SMART and direct PDK) and when applied to specimens cultured in broth-enriched medium for 6 hours (SMART-6 and CPK-6) and for 18 hours (SMART-18 and PDK-18) at 37 degrees C in alkaline peptone water. Liquid and partially formed stools were cultured and examined by means of the rapid direct test; when the initial result was negative, the tests were repeated after culture for periods of 6 and 18 hours. Rectal and fecal swabs were obtained from feces cultured in enriched-broth medium for 6 and 18 hours. In addition, we studied the sensitivity of the rapid testing systems by using pure cultures of V. cholerae 01 (strain SOS-833, CNRB, Costa Rica) that were incubated for 18 to 24 hours, and we assessed the usefulness of observing motility under the microscope in order to rationalize the use of rapid methods. The sensitivity of the direct SMART test and of the direct PDK test was 100% when samples obtained from liquid and partially formed stools and from the intestinal contents of dead bodies were used. With these samples, the direct SMART procedure showed a specificity of 100%, whereas the direct PDK procedure showed a specificity that ranged from 85.7% to 77.4%, depending on the type of sample. False positives obtained with the direct PDK method turned out to be negative with PDK-6 and PDK-18. Among the rectal and fecal swabs of persons with and without diarrhea or who had received prior treatment with antibiotics, three results that were negative with the SMART-6 procedure and two that were negative with the PDK-6 procedure turned out to be positive with the SMART-18 and PDK-18 procedures, respectively. Both systems showed excellent concordance (kappa index above 0.9) throughout. Both systems were sensitive to 6 x 10(7) colony-forming units per milliliter (cfu/mL), which was concordant with the microscopic observation of 10 microorganisms or more per field with the type of motility that characterizes vibrios (at 1000 x magnification). Samples having fewer than 10 microorganisms with the motility that characterizes vibrios had concentrations between 6 x 10(3) and 6 x 10(6) cfu/mL and became positive only after incubation in enriched-broth medium for 6 to 18 hours. We propose a strategy for diagnosing the presence of V. cholerae 01 infection in less time than it takes with traditional methods, with positive and negative predictive values of 100%. The SMART and PDK systems make it possible to accurately diagnose cholera quickly, don't require sophisticated equipment or highly qualified technical personnel, and perform satisfactorily in field conditions. Through the proposed strategy, it becomes possible to improve the specificity and sensitivity of these systems and to reduce the cost of making a diagnosis, thus making them suitable for use in cholera surveillance in low-income settings where this disease is a serious public health problem.

Fusogenic activity of PEGylated pH-sensitive liposomes.

PubMed

Vanić, Zeljka; Barnert, Sabine; Süss, Regine; Schubert, Rolf

2012-06-01

The aim of this study was to investigate the fusogenic properties of poly(ethylene glycol) (PEG)ylated dioleoylphosphatidylethanolamine/cholesteryl hemisuccinate (DOPE/CHEMS) liposomes. These pH-sensitive liposomes were prepared by incorporating two different PEG lipids: distearoylphosphatidylethanolamine (DSPE)-PEG₂₀₀₀ was mixed with the liposomal lipids using the conventional method, whereas sterol-PEG₁₁₀₀ was inserted into the outer monolayer of preformed vesicles. Both types of PEGylated liposomes were characterized and compared for their entrapment efficiency, zeta potential and size, and were tested in vitro for pH sensitivity by means of proton-induced leakage and membrane fusion activity. To mimic the routes of intracellular delivery, fusion between pH-sensitive liposomes and liposomes designed to simulate the endosomal membrane was studied. Our investigations confirmed that DOPE/CHEMS liposomes were capable of rapidly releasing calcein and of fusing upon acidification. However, after incorporation of DSPE-PEG₂₀₀₀ or sterol-PEG₁₁₀₀ into the membrane, pH sensitivity was significantly reduced; as the mol ratio of PEG-lipid was increased, the ability to fuse was decreased. Comparison between two different PEGylated pH-sensitive liposomes showed that only vesicles containing 0.6 mol% sterol-PEG₁₁₀₀ in the outer monolayer were still capable of fusing with the endosome-like liposomes and showing leakage of calcein at pH 5.5.

Real-time PCR for type-specific identification of herpes simplex in clinical samples: evaluation of type-specific results in the context of CNS diseases.

PubMed

Meylan, Sylvain; Robert, Daniel; Estrade, Christine; Grimbuehler, Valérie; Péter, Olivier; Meylan, Pascal R; Sahli, Roland

2008-02-01

HSV-1 and HSV-2 cause CNS infections of dissimilar clinico-pathological characteristics with prognostic and therapeutic implications. To validate a type-specific real-time PCR that uses MGB/LNA Taqman probes and to review the virologico-clinical data of 25 eligible patients with non-neonatal CNS infections. This real-time PCR was evaluated against conventional PCR (26 CSF and 20 quality controls), and LightCycler assay (51 mucocutaneous, 8 CSF and 32 quality controls) and culture/immunofluorescence (75 mucocutaneous) to assess typing with independent methods. Taqman real-time PCR detected 240 HSV genomes per ml CSF, a level appropriate for the management of patients, and provided unambiguous typing for the 104 positive (62 HSV-1 and 42 HSV-2) out the 160 independent clinical samples tested. HSV type diagnosed by Taqman real-time PCR predicted final diagnosis (meningitis versus encephalitis/meningoencephalitis, p<0.001) in 24/25 patients at time of presentation, in contrast to clinical evaluation. Our real-time PCR, as a sensitive and specific means for type-specific HSV diagnosis, provided rapid prognostic information for patient management.

Rapid and sensitive detection of human astrovirus in water samples by loop-mediated isothermal amplification with hydroxynaphthol blue dye.

PubMed

Yang, Bo-Yun; Liu, Xiao-Lu; Wei, Yu-Mei; Wang, Jing-Qi; He, Xiao-Qing; Jin, Yi; Wang, Zi-Jian

2014-02-14

The aim of this paper was to develop a reverse transcription loop-mediated isothermal amplification (RT-LAMP) method for rapid, sensitive and inexpensive detection of astrovirus. The detection limit of LAMP using in vitro RNA transcripts was 3.6 × 10 copies·μL⁻¹, which is as sensitive as the presently used PCR assays. However, the LAMP products could be identified as different colors with the naked eye following staining with hydroxynaphthol blue dye (HNB). No cross-reactivity with other gastroenteric viruses (rotavirus and norovirus) was observed, indicating the relatively high specificity of LAMP. The RT-LAMP method with HNB was used to effectively detect astrovirus in reclaimed water samples. The LAMP technique described in this study is a cheap, sensitive, specific and rapid method for the detection of astrovirus. The RT-LAMP method can be simply applied for the specific detection of astrovirus and has the potential to be utilized in the field as a screening test.

Evaluation of a rapid immunochromatographic ODK-0901 test for detection of pneumococcal antigen in middle ear fluids and nasopharyngeal secretions.

PubMed

Hotomi, Muneki; Togawa, Akihisa; Takei, Shin; Sugita, Gen; Sugita, Rinya; Kono, Masamitsu; Fujimaki, Yutaka; Kamide, Yosuke; Uchizono, Akihiro; Kanesada, Keiko; Sawada, Shoichi; Okitsu, Naohiro; Tanaka, Yumi; Saijo, Yoko; Yamanaka, Noboru

2012-01-01

Since the incidence of penicillin-resistant Streptococcus pneumoniae has been increasing at an astonishing rate throughout the world, the need for accurate and rapid identification of pneumococci has become increasingly important to determine the appropriate antimicrobial treatment. We have evaluated an immunochromatographic test (ODK-0901) that detects pneumococcal antigens using 264 middle ear fluids (MEFs) and 268 nasopharyngeal secretions (NPSs). A sample was defined to contain S. pneumoniae when optochin and bile sensitive alpha hemolytic streptococcal colonies were isolated by culture. The sensitivity and specificity of the ODK-0901 test were 81.4% and 80.5%, respectively, for MEFs from patients with acute otitis media (AOM). In addition, the sensitivity and specificity were 75.2% and 88.8%, respectively, for NPSs from patients with acute rhinosinusitis. The ODK-0901 test may provide a rapid and highly sensitive evaluation of the presence of S. pneumoniae and thus may be a promising method of identifying pneumococci in MEFs and NPSs.

Evaluation of a Rapid Immunochromatographic ODK-0901 Test for Detection of Pneumococcal Antigen in Middle Ear Fluids and Nasopharyngeal Secretions

PubMed Central

Hotomi, Muneki; Togawa, Akihisa; Takei, Shin; Sugita, Gen; Sugita, Rinya; Kono, Masamitsu; Fujimaki, Yutaka; Kamide, Yosuke; Uchizono, Akihiro; Kanesada, Keiko; Sawada, Shoichi; Okitsu, Naohiro; Tanaka, Yumi; Saijo, Yoko; Yamanaka, Noboru

2012-01-01

Since the incidence of penicillin-resistant Streptococcus pneumoniae has been increasing at an astonishing rate throughout the world, the need for accurate and rapid identification of pneumococci has become increasingly important to determine the appropriate antimicrobial treatment. We have evaluated an immunochromatographic test (ODK-0901) that detects pneumococcal antigens using 264 middle ear fluids (MEFs) and 268 nasopharyngeal secretions (NPSs). A sample was defined to contain S. pneumoniae when optochin and bile sensitive alpha hemolytic streptococcal colonies were isolated by culture. The sensitivity and specificity of the ODK-0901 test were 81.4% and 80.5%, respectively, for MEFs from patients with acute otitis media (AOM). In addition, the sensitivity and specificity were 75.2% and 88.8%, respectively, for NPSs from patients with acute rhinosinusitis. The ODK-0901 test may provide a rapid and highly sensitive evaluation of the presence of S. pneumoniae and thus may be a promising method of identifying pneumococci in MEFs and NPSs. PMID:22448257

All I saw was the cake. Hunger effects on attentional capture by visual food cues.

PubMed

Piech, Richard M; Pastorino, Michael T; Zald, David H

2010-06-01

While effects of hunger on motivation and food reward value are well-established, far less is known about the effects of hunger on cognitive processes. Here, we deployed the emotional blink of attention paradigm to investigate the impact of visual food cues on attentional capture under conditions of hunger and satiety. Participants were asked to detect targets which appeared in a rapid visual stream after different types of task irrelevant distractors. We observed that food stimuli acquired increased power to capture attention and prevent target detection when participants were hungry. This occurred despite monetary incentives to perform well. Our findings suggest an attentional mechanism through which hunger heightens perception of food cues. As an objective behavioral marker of the attentional sensitivity to food cues, the emotional attentional blink paradigm may provide a useful technique for studying individual differences, and state manipulations in the sensitivity to food cues. Published by Elsevier Ltd.

Application of Targeted Metabolomics to Investigate Optimum Growing Conditions to Enhance Bioactive Content of Strawberry.

PubMed

Akhatou, Ikram; Sayago, Ana; González-Domínguez, Raúl; Fernández-Recamales, Ángeles

2017-11-01

A simple, sensitive, and rapid assay based on liquid chromatography coupled to tandem mass spectrometry was designed for simultaneous quantitation of secondary metabolites in order to investigate the influence of variety and agronomic conditions on the biosynthesis of bioactive compounds in strawberry. For this purpose, strawberries belonging to three varieties with different sensitivity to environmental conditions ('Camarosa', 'Festival', 'Palomar') were grown in a soilless system under multiple agronomic conditions (electrical conductivity, substrate type, and coverage). Targeted metabolomic analysis of polyphenolic compounds, combined with advanced chemometric methods based on learning machines, revealed significant differences in multiple bioactives, such as chlorogenic acid, ellagic acid rhamnoside, sanguiin H10, quercetin 3-O-glucuronide, catechin, procyanidin B2, pelargonidin 3-O-glucoside, cyanidin 3-O-glucoside, and pelargonidin 3-O-rutinoside, which play a pivotal role in organoleptic properties and beneficial healthy effects of these polyphenol-rich foods.

Usefulness of Leifson Staining Method in Diagnosis of Helicobacter pylori Infection

PubMed Central

Piccolomini, Raffaele; Di Bonaventura, Giovanni; Neri, Matteo; Di Girolamo, Arturo; Catamo, Giovanni; Pizzigallo, Eligio

1999-01-01

The Leifson staining method was used to diagnose Helicobacter pylori infection and was compared to histology, culture, and the rapid urease test (RUT). Histology gave the best sensitivity (98%), compared to Leifson staining (97%), culture (92%), and RUT (85%) (P < 0.005). Leifson staining is a sensitive, rapid, economical method for diagnosis of H. pylori infection in dyspeptic patients. PMID:9854090

Rapid label-free identification of Klebsiella pneumoniae antibiotic resistant strains by the drop-coating deposition surface-enhanced Raman scattering method

NASA Astrophysics Data System (ADS)

Cheong, Youjin; Kim, Young Jin; Kang, Heeyoon; Choi, Samjin; Lee, Hee Joo

2017-08-01

Although many methodologies have been developed to identify unknown bacteria, bacterial identification in clinical microbiology remains a complex and time-consuming procedure. To address this problem, we developed a label-free method for rapidly identifying clinically relevant multilocus sequencing typing-verified quinolone-resistant Klebsiella pneumoniae strains. We also applied the method to identify three strains from colony samples, ATCC70063 (control), ST11 and ST15; these are the prevalent quinolone-resistant K. pneumoniae strains in East Asia. The colonies were identified using a drop-coating deposition surface-enhanced Raman scattering (DCD-SERS) procedure coupled with a multivariate statistical method. Our workflow exhibited an enhancement factor of 11.3 × 106 to Raman intensities, high reproducibility (relative standard deviation of 7.4%), and a sensitive limit of detection (100 pM rhodamine 6G), with a correlation coefficient of 0.98. All quinolone-resistant K. pneumoniae strains showed similar spectral Raman shifts (high correlations) regardless of bacterial type, as well as different Raman vibrational modes compared to Escherichia coli strains. Our proposed DCD-SERS procedure coupled with the multivariate statistics-based identification method achieved excellent performance in discriminating similar microbes from one another and also in subtyping of K. pneumoniae strains. Therefore, our label-free DCD-SERS procedure coupled with the computational decision supporting method is a potentially useful method for the rapid identification of clinically relevant K. pneumoniae strains.

A combinatorial histidine scanning library approach to engineer highly pH-dependent protein switches

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

Murtaugh, Megan L.; Fanning, Sean W.; Sharma, Tressa M.

2012-09-05

There is growing interest in the development of protein switches, which are proteins whose function, such as binding a target molecule, can be modulated through environmental triggers. Efforts to engineer highly pH sensitive protein-protein interactions typically rely on the rational introduction of ionizable groups in the protein interface. Such experiments are typically time intensive and often sacrifice the protein's affinity at the permissive pH. The underlying thermodynamics of proton-linkage dictate that the presence of multiple ionizable groups, which undergo a pK{sub a} change on protein binding, are necessary to result in highly pH-dependent binding. To test this hypothesis, a novelmore » combinatorial histidine library was developed where every possible combination of histidine and wild-type residue is sampled throughout the interface of a model anti-RNase A single domain VHH antibody. Antibodies were coselected for high-affinity binding and pH-sensitivity using an in vitro, dual-function selection strategy. The resulting antibodies retained near wild-type affinity yet became highly sensitive to small decreases in pH, drastically decreasing their binding affinity, due to the incorporation of multiple histidine groups. Several trends were observed, such as histidine 'hot-spots,' which will help enhance the development of pH switch proteins as well as increase our understanding of the role of ionizable residues in protein interfaces. Overall, the combinatorial approach is rapid, general, and robust and should be capable of producing highly pH-sensitive protein affinity reagents for a number of different applications.« less

Improved Sensitivity for Molecular Detection of Bacterial and Candida Infections in Blood

PubMed Central

Bacconi, Andrea; Richmond, Gregory S.; Baroldi, Michelle A.; Laffler, Thomas G.; Blyn, Lawrence B.; Carolan, Heather E.; Frinder, Mark R.; Toleno, Donna M.; Metzgar, David; Gutierrez, Jose R.; Massire, Christian; Rounds, Megan; Kennel, Natalie J.; Rothman, Richard E.; Peterson, Stephen; Carroll, Karen C.; Wakefield, Teresa; Ecker, David J.

2014-01-01

The rapid identification of bacteria and fungi directly from the blood of patients with suspected bloodstream infections aids in diagnosis and guides treatment decisions. The development of an automated, rapid, and sensitive molecular technology capable of detecting the diverse agents of such infections at low titers has been challenging, due in part to the high background of genomic DNA in blood. PCR followed by electrospray ionization mass spectrometry (PCR/ESI-MS) allows for the rapid and accurate identification of microorganisms but with a sensitivity of about 50% compared to that of culture when using 1-ml whole-blood specimens. Here, we describe a new integrated specimen preparation technology that substantially improves the sensitivity of PCR/ESI-MS analysis. An efficient lysis method and automated DNA purification system were designed for processing 5 ml of whole blood. In addition, PCR amplification formulations were optimized to tolerate high levels of human DNA. An analysis of 331 specimens collected from patients with suspected bloodstream infections resulted in 35 PCR/ESI-MS-positive specimens (10.6%) compared to 18 positive by culture (5.4%). PCR/ESI-MS was 83% sensitive and 94% specific compared to culture. Replicate PCR/ESI-MS testing from a second aliquot of the PCR/ESI-MS-positive/culture-negative specimens corroborated the initial findings in most cases, resulting in increased sensitivity (91%) and specificity (99%) when confirmed detections were considered true positives. The integrated solution described here has the potential to provide rapid detection and identification of organisms responsible for bloodstream infections. PMID:24951806

A multiplex PCR assay for the rapid and sensitive detection of methicillin-resistant Staphylococcus aureus and simultaneous discrimination of Staphylococcus aureus from coagulase-negative staphylococci.

PubMed

Xu, Benjin; Liu, Ling; Liu, Li; Li, Xinping; Li, Xiaofang; Wang, Xin

2012-11-01

Methicillin-resistant Staphylococcus aureus (MRSA) is a global health concern, which had been detected in food and food production animals. Conventional testing for detection of MRSA takes 3 to 5 d to yield complete information of the organism and its antibiotic sensitivity pattern. So, a rapid method is needed to diagnose and treat the MRSA infections. The present study focused on the development of a multiplex PCR assay for the rapid and sensitive detection of MRSA. The assay simultaneously detected 4 genes, namely, 16S rRNA of the Staphylococcus genus, femA of S. aureus, mecA that encodes methicillin resistance, and one internal control. It was rapid and yielded results within 4 h. The analytical sensitivity and specificity of the multiplex PCR assay was evaluated by comparing it with the conventional method. The analytical sensitivity of the multiplex PCR assay at the DNA level was 10 ng DNA. The analytical specificity was evaluated with 10 reference staphylococci strains and was 100%. The diagnostic evaluation of MRSA was carried out using 360 foodborne staphylococci isolates, and showed 99.1% of specificity, 96.4% of sensitivity, 97.5% of positive predictive value, and 97.3% of negative predictive value compared to the conventional method. The inclusion of an internal control in the multiplex PCR assay is important to exclude false-negative cases. This test can be used as an effective diagnostic and surveillance tool to investigate the spread and emergence of MRSA. © 2012 Institute of Food Technologists®

Lab on a chip sensor for rapid detection and antibiotic resistance determination of Staphylococcus aureus.

PubMed

Abeyrathne, Chathurika D; Huynh, Duc H; Mcintire, Thomas W; Nguyen, Thanh C; Nasr, Babak; Zantomio, Daniela; Chana, Gursharan; Abbott, Iain; Choong, Peter; Catton, Mike; Skafidas, Efstratios

2016-03-21

The Gram-positive bacterium, Staphylococcus aureus (S. aureus), is a major pathogen responsible for a variety of infectious diseases ranging from cellulitis to more serious conditions such as septic arthritis and septicaemia. Timely treatment with appropriate antibiotic therapy is essential to ensure clinical defervescence and to prevent further complications such as infective endocarditis or organ impairment due to septic shock. To date, initial antibiotic choice is empirical, using a "best guess" of likely organism and sensitivity- an approach adopted due to the lack of rapid identification methods for bacteria. Current culture based methods take up to 5 days to identify the causative bacterial pathogen and its antibiotic sensitivity. This paper provides proof of concept for a biosensor, based on interdigitated electrodes, to detect the presence of S. aureus and ascertain its sensitivity to flucloxacillin rapidly (within 2 hours) in a cost effective manner. The proposed method is label-free and uses non-faradic measurements. This is the first study to successfully employ interdigitated electrodes for the rapid detection of antibiotic resistance. The method described has important potential outcomes of faster definitive antibiotic treatment and more rapid clinical response to treatment.

Characterizing of tissue microstructure with single-detector polarization-sensitive optical coherence tomography

NASA Astrophysics Data System (ADS)

Liu, Bin; Harman, Michelle; Giattina, Susanne; Stamper, Debra L.; Demakis, Charles; Chilek, Mark; Raby, Stephanie; Brezinski, Mark E.

2006-06-01

Assessing tissue birefringence with imaging modality polarization-sensitive optical coherence tomography (PS-OCT) could improve the characterization of in vivo tissue pathology. Among the birefringent components, collagen may provide invaluable clinical information because of its alteration in disorders ranging from myocardial infarction to arthritis. But the features required of clinical imaging modality in these areas usually include the ability to assess the parameter of interest rapidly and without extensive data analysis, the characteristics that single-detector PS-OCT demonstrates. But beyond detecting organized collagen, which has been previously demonstrated and confirmed with the appropriate histological techniques, additional information can potentially be gained with PS-OCT, including collagen type, form versus intrinsic birefringence, the collagen angle, and the presence of multiple birefringence materials. In part I, we apply the simple but powerful fast-Fourier transform (FFT) to both PS-OCT mathematical modeling and in vitro bovine meniscus for improved PS-OCT data analysis. The FFT analysis yields, in a rapid, straightforward, and easily interpreted manner, information on the presence of multiple birefringent materials, distinguishing the true anatomical structure from patterns in image resulting from alterations in the polarization state and identifying the tissue/phantom optical axes. Therefore the use of the FFT analysis of PS-OCT data provides information on tissue composition beyond identifying the presence of organized collagen in real time and directly from the image without extensive mathematical manipulation or data analysis. In part II, Helistat phantoms (collagen type I) are analyzed with the ultimate goal of improved tissue characterization. This study, along with the data in part I, advance the insights gained from PS-OCT images beyond simply determining the presence or absence of birefringence.

[Diagnostic and prognostic value of heart-type fatty acid-binding protein (H-FABP), an early biochemical marker of myocardial injury].

PubMed

Bertinchant, J P; Polge, A

2005-12-01

Heart-type fatty acid-binding protein (H-FABP) is a 132 amino acids soluble protein, with general characteristics resembling myoglobin. Because of its low molecular weight (15 kd) and cytoplasmic location, it constitutes a biologic marker readily released into the circulation after myocardial injury. Despite the development of various immunoassays to measure H-FABP, few are currently easy to perform, quantitative and applicable in emergency. Most studies have shown the diagnostic sensitivity of H-FABP (i.e. its ability to detect the presence of a myocardial infarction) to be high, above that of myoglobin in patients presenting within 3 to 6 h of after the onset of chest pain. This superiority is attributable to an earlier and more rapid rise in H-FABP than in myoglobin. After thrombolysis, the serum concentrations of H-FABP peak at approximately 4 h after the onset of chest pain, and return to normal values within 24 h. Because of this rapid return of its blood concentration to baseline, H-FABP can contribute to an early biologic diagnosis of post-thrombolysis reperfusion and re-infarction. In absence of renal insufficiency, H-FABP also provides a reliable estimate of infarct size associated with ST segment elevation. When myocardial injury occurs after cardiac surgery, the second peak in H-FABP concentration precedes that of myoglobin, CK-MB or troponins. In addition, H-FABP peaks earlier and is more sensitive than troponins in the detection of subtle myocardial injury in patients presenting with acute coronary syndrome without ST segment elevation, and in patients with severe heart failure, thus offering early prognostic information. Limitations of H-FABP include a limited cardio-specificity, a narrow diagnostic window (20 to 30 h), and a nearly exclusive renal elimination.

Diagnostic value of a heart-type fatty acid-binding protein (H-FABP) bedside test in suspected acute coronary syndrome in primary care.

PubMed

Bruins Slot, M H E; Rutten, F H; van der Heijden, G J M G; Doevendans, P A; Mast, E G; Bredero, A C; van der Spoel, O P; Glatz, J F C; Hoes, A W

2013-09-30

To determine the diagnostic accuracy of a rapid heart-type fatty acid-binding protein (H-FABP) test in patients suspected of acute coronary syndrome (ACS) in primary care. General practitioners included 298 patients suspected of ACS. In all patients, whether referred to hospital or not, ECG and cardiac biomarker testing was performed. ACS was determined in accordance with international guidelines. Multivariate analysis was used to determine the value of H-FABP in addition to clinical findings. Mean patient age was 66 years (SD 14), 52% was female and 66 patients (22%) were diagnosed with ACS. The H-FABP bedside test was performed within 24h (median 3.1, IQR 1.5 to 7.1) after symptom onset. The positive predictive value (PPV) of H-FABP was 65% (95% confidence interval (CI) 50-78). The negative predictive value (NPV) was 85% (95% CI 80-88). Sensitivity was 39% (29-51%) and specificity 94% (90-96%). Within 6h after symptom onset, the PPV was 72% (55-84) and the NPV was 83% (77-88), sensitivity 43% (31-57%) and specificity 94% (89-97%). Adding the H-FABP test to a diagnostic model for ACS led to an increase in the area under the receiver operating curve from 0.66 (95% CI 0.58-0.73) to 0.75 (95% CI 0.68-0.82). The H-FABP rapid test provides modest additional diagnostic certainty in primary care. It cannot be used to safely exclude rule out ACS. The test can only be used safely in patients otherwise NOT referred to hospital by the GP, as an extra precaution not to miss ACS ('rule in'). Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

The effect of agglomeration state of silver and titanium dioxide nanoparticles on cellular response of HepG2, A549 and THP-1 cells.

PubMed

Lankoff, Anna; Sandberg, Wiggo J; Wegierek-Ciuk, Aneta; Lisowska, Halina; Refsnes, Magne; Sartowska, Bożena; Schwarze, Per E; Meczynska-Wielgosz, Sylwia; Wojewodzka, Maria; Kruszewski, Marcin

2012-02-05

Nanoparticles (NPs) occurring in the environment rapidly agglomerate and form particles of larger diameters. The extent to which this abates the effects of NPs has not been clarified. The motivation of this study was to examine how the agglomeration/aggregation state of silver (20nm and 200nm) and titanium dioxide (21nm) nanoparticles may affect the kinetics of cellular binding/uptake and ability to induce cytotoxic responses in THP1, HepG2 and A549 cells. Cellular binding/uptake, metabolic activation and cell death were assessed by the SSC flow cytometry measurements, the MTT-test and the propidium iodide assay. The three types of particles were efficiently taken up by the cells, decreasing metabolic activation and increasing cell death in all the cell lines. The magnitude of the studied endpoints depended on the agglomeration/aggregation state of particles, their size, time-point and cell type. Among the three cell lines tested, A549 cells were the most sensitive to these particles in relation to cellular binding/uptake. HepG2 cells showed a tendency to be more sensitive in relation to metabolic activation. THP-1 cells were the most resistant to all three types of particles in relation to all endpoints tested. Our findings suggest that particle features such as size and agglomeration status as well as the type of cells may contribute to nanoparticles biological impact. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

A new method for simultaneous detection and discrimination of Bovine herpesvirus types 1 (BoHV-1) and 5 (BoHV-5) using real time PCR with high resolution melting (HRM) analysis.

PubMed

Marin, M S; Quintana, S; Leunda, M R; Recavarren, M; Pagnuco, I; Späth, E; Pérez, S; Odeón, A

2016-01-01

Bovine herpesvirus types 1 (BoHV-1) and 5 (BoHV-5) are antigenically and genetically similar. The aim of this study was to develop a simple and reliable one-step real time PCR assay with high resolution melting (HRM) analysis for the simultaneous detection and differentiation of BoHV-1 and BoHV-5. Optimization of assay conditions was performed with DNA from reference strains. Then, DNA from field isolates, clinical samples and tissue samples of experimentally infected animals were studied by real time PCR-HRM. An efficient amplification of real time PCR products was obtained, and a clear melting curve and appropriate melting peaks for both viruses were achieved in the HRM curve analysis for BoHV type identification. BoHV was identified in all of the isolates and clinical samples, and BoHV types were properly differentiated. Furthermore, viral DNA was detected in 12/18 and 7/18 samples from BoHV-1- and BoHV-5-infected calves, respectively. Real time PCR-HRM achieved a higher sensitivity compared with virus isolation or conventional PCR. In this study, HRM was used as a novel procedure. This method provides rapid, sensitive, specific and simultaneous detection of bovine alpha-herpesviruses DNA. Thus, this technique is an excellent tool for diagnosis, research and epidemiological studies of these viruses in cattle. Copyright © 2015 Elsevier B.V. All rights reserved.

The Usher Syndrome Type IIIB Histidyl-tRNA Synthetase Mutation Confers Temperature Sensitivity.

PubMed

Abbott, Jamie A; Guth, Ethan; Kim, Cindy; Regan, Cathy; Siu, Victoria M; Rupar, C Anthony; Demeler, Borries; Francklyn, Christopher S; Robey-Bond, Susan M

2017-07-18

Histidyl-tRNA synthetase (HARS) is a highly conserved translation factor that plays an essential role in protein synthesis. HARS has been implicated in the human syndromes Charcot-Marie-Tooth (CMT) Type 2W and Type IIIB Usher (USH3B). The USH3B mutation, which encodes a Y454S substitution in HARS, is inherited in an autosomal recessive fashion and associated with childhood deafness, blindness, and episodic hallucinations during acute illness. The biochemical basis of the pathophysiologies linked to USH3B is currently unknown. Here, we present a detailed functional comparison of wild-type (WT) and Y454S HARS enzymes. Kinetic parameters for enzymes and canonical substrates were determined using both steady state and rapid kinetics. Enzyme stability was examined using differential scanning fluorimetry. Finally, enzyme functionality in a primary cell culture was assessed. Our results demonstrate that the Y454S substitution leaves HARS amino acid activation, aminoacylation, and tRNA His binding functions largely intact compared with those of WT HARS, and the mutant enzyme dimerizes like the wild type does. Interestingly, during our investigation, it was revealed that the kinetics of amino acid activation differs from that of the previously characterized bacterial HisRS. Despite the similar kinetics, differential scanning fluorimetry revealed that Y454S is less thermally stable than WT HARS, and cells from Y454S patients grown at elevated temperatures demonstrate diminished levels of protein synthesis compared to those of WT cells. The thermal sensitivity associated with the Y454S mutation represents a biochemical basis for understanding USH3B.

Systematic review, meta-analysis and economic modelling of molecular diagnostic tests for antibiotic resistance in tuberculosis.

PubMed

Drobniewski, Francis; Cooke, Mary; Jordan, Jake; Casali, Nicola; Mugwagwa, Tendai; Broda, Agnieszka; Townsend, Catherine; Sivaramakrishnan, Anand; Green, Nathan; Jit, Mark; Lipman, Marc; Lord, Joanne; White, Peter J; Abubakar, Ibrahim

2015-05-01

Drug-resistant tuberculosis (TB), especially multidrug-resistant (MDR, resistance to rifampicin and isoniazid) disease, is associated with a worse patient outcome. Drug resistance diagnosed using microbiological culture takes days to weeks, as TB bacteria grow slowly. Rapid molecular tests for drug resistance detection (1 day) are commercially available and may promote faster initiation of appropriate treatment. To (1) conduct a systematic review of evidence regarding diagnostic accuracy of molecular genetic tests for drug resistance, (2) conduct a health-economic evaluation of screening and diagnostic strategies, including comparison of alternative models of service provision and assessment of the value of targeting rapid testing at high-risk subgroups, and (3) construct a transmission-dynamic mathematical model that translates the estimates of diagnostic accuracy into estimates of clinical impact. A standardised search strategy identified relevant studies from EMBASE, PubMed, MEDLINE, Bioscience Information Service (BIOSIS), System for Information on Grey Literature in Europe Social Policy & Practice (SIGLE) and Web of Science, published between 1 January 2000 and 15 August 2013. Additional 'grey' sources were included. Quality was assessed using quality assessment of diagnostic accuracy studies version 2 (QUADAS-2). For each diagnostic strategy and population subgroup, a care pathway was constructed to specify which medical treatments and health services that individuals would receive from presentation to the point where they either did or did not complete TB treatment successfully. A total cost was estimated from a health service perspective for each care pathway, and the health impact was estimated in terms of the mean discounted quality-adjusted life-years (QALYs) lost as a result of disease and treatment. Costs and QALYs were both discounted at 3.5% per year. An integrated transmission-dynamic and economic model was used to evaluate the cost-effectiveness of introducing rapid molecular testing (in addition to culture and drug sensitivity testing). Probabilistic sensitivity analysis was performed to evaluate the impact on cost-effectiveness of diagnostic and treatment time delays, diagnosis and treatment costs, and associated QALYs. A total of 8922 titles and abstracts were identified, with 557 papers being potentially eligible. Of these, 56 studies contained sufficient test information for analysis. All three commercial tests performed well when detecting drug resistance in clinical samples, although with evidence of heterogeneity between studies. Pooled sensitivity for GenoType® MTBDRplus (Hain Lifescience, Nehren, Germany) (isoniazid and rifampicin resistance), INNO-LiPA Rif.TB® (Fujirebio Europe, Ghent, Belgium) (rifampicin resistance) and Xpert® MTB/RIF (Cepheid Inc., Sunnyvale, CA, USA) (rifampicin resistance) was 83.4%, 94.6%, 95.4% and 96.8%, respectively; equivalent pooled specificity was 99.6%, 98.2%, 99.7% and 98.4%, respectively. Results of the transmission model suggest that all of the rapid assays considered here, if added to the current diagnostic pathway, would be cost-saving and achieve a reduction in expected QALY loss compared with current practice. GenoType MTBDRplus appeared to be the most cost-effective of the rapid tests in the South Asian population, although results were similar for GeneXpert. In all other scenarios GeneXpert appeared to be the most cost-effective strategy. Rapid molecular tests for rifampicin and isoniazid resistance were sensitive and specific. They may also be cost-effective when added to culture drug susceptibility testing in the UK. There is global interest in point-of-care testing and further work is needed to review the performance of emerging tests and the wider health-economic impact of decentralised testing in clinics and primary care, as well as non-health-care settings, such as shelters and prisons. This study is registered as PROSPERO CRD42011001537. The National Institute for Health Research Health Technology Assessment programme.

A multiplexed reverse transcriptase PCR assay for identification of viral respiratory pathogens at point-of-care

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

Letant, S E; .Ortiz, J I; Tammero, L

2007-04-11

We have developed a nucleic acid-based assay that is rapid, sensitive, specific, and can be used for the simultaneous detection of 5 common human respiratory pathogens including influenza A, influenza B, parainfluenza type 1 and 3, respiratory syncytial virus, and adenovirus group B, C, and E. Typically, diagnosis on an un-extracted clinical sample can be provided in less than 3 hours, including sample collection, preparation, and processing, as well as data analysis. Such a multiplexed panel would enable rapid broad-spectrum pathogen testing on nasal swabs, and therefore allow implementation of infection control measures, and timely administration of antiviral therapies. Thismore » article presents a summary of the assay performance in terms of sensitivity and specificity. Limits of detection are provided for each targeted respiratory pathogen, and result comparisons are performed on clinical samples, our goal being to compare the sensitivity and specificity of the multiplexed assay to the combination of immunofluorescence and shell vial culture currently implemented at the UCDMC hospital. Overall, the use of the multiplexed RT-PCR assay reduced the rate of false negatives by 4% and reduced the rate of false positives by up to 10%. The assay correctly identified 99.3% of the clinical negatives, 97% of adenovirus, 95% of RSV, 92% of influenza B, and 77% of influenza A without any extraction performed on the clinical samples. The data also showed that extraction will be needed for parainfluenza virus, which was only identified correctly 24% of the time on un-extracted samples.« less

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.

Recent Advances in Exosomal Protein Detection Via Liquid Biopsy Biosensors for Cancer Screening, Diagnosis, and Prognosis.

PubMed

Liu, Chang; Yang, Yunchen; Wu, Yun

2018-03-08

Current cancer diagnostic methods are challenged by low sensitivity, high false positive rate, limited tumor information, uncomfortable or invasive procedures, and high cost. Liquid biopsy that analyzes circulating biomarkers in body fluids represents a promising solution to these challenges. Exosomes are one of the promising cancer biomarkers for liquid biopsy because they are cell-secreted, nano-sized, extracellular vesicles that stably exist in all types of body fluids. Exosomes transfer DNAs, RNAs, proteins, and lipids from parent cells to recipient cells for intercellular communication and play important roles in cancer initiation, progression, and metastasis. Many liquid biopsy biosensors have been developed to offer non- or minimally-invasive, highly sensitive, simple, rapid, and cost-effective cancer diagnostics. This review summarized recent advances of liquid biopsy biosensors with a focus on the detection of exosomal proteins as biomarkers for cancer screening, diagnosis, and prognosis. We reviewed six major types of liquid biopsy biosensors including immunofluorescence biosensor, colorimetric biosensor, surface plasmon resonance (SPR) biosensor, surface-enhanced Raman scattering (SERS) biosensor, electrochemical biosensor, and nuclear magnetic resonance (NMR) biosensor. We shared our perspectives on future improvement of exosome-based liquid biopsy biosensors to accelerate their clinical translation.

Comparative analysis of sixteen flavonoids from different parts of Sophora flavescens Ait. by ultra high-performance liquid chromatography-tandem mass spectrometry.

PubMed

Weng, Zebin; Zeng, Fei; Zhu, Zhenhua; Qian, Dawei; Guo, Sheng; Wang, Hanqing; Duan, Jin-Ao

2018-07-15

The root of Sophora flavescens Ait. has long been used as a crude drug in China and other Asian countries for thousands of years. The quinolizidine alkaloids and flavonoids are considered as the main bioactive components in this plant. To determine the distribution and content of the flavonoids in different organs of this plant, a rapid, sensitive and reproducible method was established using ultra-high-performance liquid chromatography coupled with a triple quadrupole electrospray tandem mass spectrometry. A total of sixteen flavonoids including five different types (isoflavones, pterocarpans, flavones, flavonols and prenylflavonoids) were simultaneously determined in 10 min. The established method was fully validated in terms of linearity, sensitivity, precision, repeatability as well as recovery and successfully applied in the methanolic extracts of S. flavescens parts (root, stem, leaf, pod and seed). The analysis results indicated that the distribution and contents of different type of flavonoids showed remarkable differences among the five organs of S. flavescens. This study might be useful for the rational utilization of S. flavescens resource. Copyright © 2018 Elsevier B.V. All rights reserved.

Rapid and sensitive detection of mink circovirus by recombinase polymerase amplification.

PubMed

Ge, Junwei; Shi, Yunjia; Cui, Xingyang; Gu, Shanshan; Zhao, Lili; Chen, Hongyan

2018-06-01

To date, the pathogenic role of mink circovirus (MiCV) remains unclear, and its prevalence and economic importance are unknown. Therefore, a rapid and sensitive molecular diagnosis is necessary for disease management and epidemiological surveillance. However, only PCR methods can identify MiCV infection at present. In this study, we developed a nested PCR and established a novel recombinase polymerase amplification (RPA) assay for MiCV detection. Sensitivity analysis showed that the detection limit of nested PCR and RPA assay was 10 1 copies/reaction, and these methods were more sensitive than conventional PCR, which has a detection limit of 10 5 copies/reaction. The RPA assay had no cross-reactivity with other related viral pathogens, and amplification was completed in less than 20 min with a simple device. Further assessment of clinical samples showed that the two assays were accurate in identifying positive and negative conventional PCR samples. The detection rate of MiCV by the RPA assay in clinical samples was 38.09%, which was 97% consistent with that by the nested PCR. The developed nested PCR is a highly sensitive tool for practical use, and the RPA assay is a simple, sensitive, and potential alternative method for rapid and accurate MiCV diagnosis. Copyright © 2018 Elsevier B.V. All rights reserved.

Study and evaluation of Wondfo rapid diagnostic kit based on nano-gold immunochromatography assay for diagnosis of Plasmodium falciparum.

PubMed

Peng, Yunping; Wu, Junlin; Wang, Jihua; Li, Wenmei; Yu, Shujuan

2012-04-01

Malaria has been recognized as a human disease for thousands of years and remains one of the most common diseases affecting humans worldwide. Therefore, a method for rapidly detecting Plasmodium falciparum is necessary and useful. We have developed Wondfo rapid diagnostic kit based on nano-gold immunochromatography assay for the detection of P. falciparum in patient specimen. In the present study, we demonstrated the sensitivity and specificity of the rapid diagnostic kit in which nano-gold labeling techniques and the monoclonal antibodies against histidine-rich protein-2 of P. falciparum were used to establish two-antibody sandwich immunochromatographic assay for detecting P. falciparum. By using microscopic examination of blood smears as control, the sensitivity, specificity, and feasibility of Wondfo rapid diagnostic kit was determined in the prompt and accurate diagnosis of malaria. In this study, 1,558 blood samples were collected from outpatient clinics in China and detected by both Wondfo kit and microscopic examination. The Wondfo kit did not show cross-reaction with microfilaria, Toxoplasma gondii, and other parasites in the blood. The patient samples positive for rheumatoid factor, HIV, tuberculosis, and syphilis did not show false positivity when testing with Wondfo kit. The detection sensitivity and specificity of Wondfo rapid diagnostic kit were 95.49% and 99.53%, respectively. These results indicate that our rapid diagnostic assay may be useful for detecting P. falciparum in patient specimen.

Combining magnetic nanoparticle with biotinylated nanobodies for rapid and sensitive detection of influenza H3N2

PubMed Central

2014-01-01

Our objective is to develop a rapid and sensitive assay based on magnetic beads to detect the concentration of influenza H3N2. The possibility of using variable domain heavy-chain antibodies (nanobody) as diagnostic tools for influenza H3N2 was investigated. A healthy camel was immunized with inactivated influenza H3N2. A nanobody library of 8 × 108 clones was constructed and phage displayed. After three successive biopanning steps, H3N2-specific nanobodies were successfully isolated, expressed in Escherichia coli, and purified. Sequence analysis of the nanobodies revealed that we possessed four classes of nanobodies against H3N2. Two nanobodies were further used to prepare our rapid diagnostic kit. Biotinylated nanobody was effectively immobilized onto the surface of streptavidin magnetic beads. The modified magnetic beads with nanobody capture specifically influenza H3N2 and can still be recognized by nanobodies conjugated to horseradish peroxidase (HRP) conjugates. Under optimized conditions, the present immunoassay exhibited a relatively high sensitive detection with a limit of 50 ng/mL. In conclusion, by combining magnetic beads with specific nanobodies, this assay provides a promising influenza detection assay to develop a potential rapid, sensitive, and low-cost diagnostic tool to screen for influenza infections. PMID:25328501

Combining magnetic nanoparticle with biotinylated nanobodies for rapid and sensitive detection of influenza H3N2

NASA Astrophysics Data System (ADS)

Zhu, Min; Hu, Yonghong; Li, Guirong; Ou, Weijun; Mao, Panyong; Xin, Shaojie; Wan, Yakun

2014-09-01

Our objective is to develop a rapid and sensitive assay based on magnetic beads to detect the concentration of influenza H3N2. The possibility of using variable domain heavy-chain antibodies (nanobody) as diagnostic tools for influenza H3N2 was investigated. A healthy camel was immunized with inactivated influenza H3N2. A nanobody library of 8 × 108 clones was constructed and phage displayed. After three successive biopanning steps, H3N2-specific nanobodies were successfully isolated, expressed in Escherichia coli, and purified. Sequence analysis of the nanobodies revealed that we possessed four classes of nanobodies against H3N2. Two nanobodies were further used to prepare our rapid diagnostic kit. Biotinylated nanobody was effectively immobilized onto the surface of streptavidin magnetic beads. The modified magnetic beads with nanobody capture specifically influenza H3N2 and can still be recognized by nanobodies conjugated to horseradish peroxidase (HRP) conjugates. Under optimized conditions, the present immunoassay exhibited a relatively high sensitive detection with a limit of 50 ng/mL. In conclusion, by combining magnetic beads with specific nanobodies, this assay provides a promising influenza detection assay to develop a potential rapid, sensitive, and low-cost diagnostic tool to screen for influenza infections.

A novel immunochromatographic electrochemical biosensor for highly sensitive and selective detection of trichloropyridinol, a biomarker of exposure to chlorpyrifos.

PubMed

Wang, Limin; Lu, Donglai; Wang, Jun; Du, Dan; Zou, Zhexiang; Wang, Hua; Smith, Jordan N; Timchalk, Charles; Liu, Fengquan; Lin, Yuehe

2011-02-15

We present a novel portable immunochromatographic electrochemical biosensor (IEB) for simple, rapid, and sensitive biomonitoring of trichloropyridinol (TCP), a metabolite biomarker of exposure to organophosphorus insecticides. Our new approach takes the advantage of immunochromatographic test strip for a rapid competitive immunoreaction and a disposable screen-printed carbon electrode for a rapid and sensitive electrochemical analysis of captured HRP labeling. Several key experimental parameters (e.g. immunoreaction time, the amount of HRP labeled TCP, concentration of the substrate for electrochemical measurements, and the blocking agents for the nitrocellulose membrane) were optimized to achieve a high sensitivity, selectivity and stability. Under optimal conditions, the IEB has demonstrated a wide linear range (0.1-100 ng/ml) with a detection limit as low as 0.1 ng/ml TCP. Furthermore, the IEB has been successfully applied for biomonitoring of TCP in the rat plasma samples with in vivo exposure to organophosphorus insecticides like Chlorpyrifos-oxon (CPF-oxon). The IEB thus opens up new pathways for designing a simple, rapid, clinically accurate, and quantitative tool for TCP detection, as well as holds a great promise for in-field screening of metabolite biomarkers, e.g., TCP, for humans exposed to organophosphorus insecticides. Copyright © 2010 Elsevier B.V. All rights reserved.

Spray Inlet Proton Transfer Reaction Mass Spectrometry (SI-PTR-MS) for Rapid and Sensitive Online Monitoring of Benzene in Water.

PubMed

Zou, Xue; Kang, Meng; Li, Aiyue; Shen, Chengyin; Chu, Yannan

2016-03-15

Rapid and sensitive monitoring of benzene in water is very important to the health of people and for environmental protection. A novel and online detection method of spray inlet proton transfer reaction mass spectrometry (SI-PTR-MS) was introduced for rapid and sensitive monitoring of trace benzene in water. A spraying extraction system was coupled with the self-developed PTR-MS. The benzene was extracted from the water sample in the spraying extraction system and continuously detected with PTR-MS. The flow of carrier gas and salt concentration in water were optimized to be 50 sccm and 20% (w/v), respectively. The response time and the limit of detection of the SI-PTR-MS for detection of benzene in water were 55 s and 0.14 μg/L at 10 s integration time, respectively. The repeatability of the SI-PTR-MS was evaluated, and the relative standard deviation of five replicate determinations was 4.3%. The SI-PTR-MS system was employed for monitoring benzene in different water matrices, such as tap water, lake water, and wastewater. The results indicated that the online SI-PTR-MS can be used for rapid and sensitive monitoring of trace benzene in water.

Effects of Short-Term Very Low Calorie Diet on Intramyocellular Lipid and Insulin Sensitivity in Non-diabetics and Type 2 Diabetic Patients

PubMed Central

Lara-Castro, Cristina; Newcomer, Bradley R; Rowell, Jennifer; Wallace, Penny; Shaughnessy, Sara M; Munoz, A Julian; Shiflett, Alanna M; Rigsby, Dana Y; Lawrence, Jeannine C; Bohning, Daryl E; Buchthal, Steven; Garvey, W Timothy

2008-01-01

Objective To study the effects of a short-term very-low calorie diet (VLCD) on intramyocellular lipid (IMCL), total body fat, and insulin sensitivity in a group of obese non-diabetic and Type 2 Diabetic (T2DM) patients. Research Methods and Procedures Seven untreated T2DM and 5 obese non-diabetic individuals were studied before and after a 6-day VLCD using proton-magnetic resonance spectroscopy to quantify IMCL, DXA to assess body fat, and hyperinsulinemic-euglycemic clamps to measure peripheral insulin sensitivity. Results In both groups, decrements in total body fat mass and BMI were small but statistically significant. In contrast, the diet resulted in a pronounced reduction in IMCL compared to baseline values in non-diabetics (56% decrease) and T2DM (40% decrease), P<0.05, and this was accompanied by an overall 9.3% increase in maximally-stimulated glucose disposal rate (P<0.01). IMCL was significantly correlated with insulin sensitivity, (r=−0.69; P<0.01) and waist circumference (r = 0.72 and 0.83, baseline and post-diet respectively, both P < 0.01), but neither IMCL nor insulin sensitivity was related to measures of general adiposity such as BMI, % body fat, or total body fat (P=NS). Conclusions Short-term VLCD is accompanied by small decrements in general adiposity, marked decrease in IMCL, and an increase in insulin sensitivity in non-diabetic and T2DM subjects. Therefore, rapid amelioration of insulin resistance by VLCD can be partially explained by loss of IMCL in both non-diabetics and in T2DM in the absence of substantial changes in total body fat. These observations are consistent with the idea that insulin resistance is more directly related to IMCL rather than body fat per se. PMID:18078853

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

Gardner, Carol R., E-mail: cgardner@pharmacy.rutgers.edu; Hankey, Pamela; Mishin, Vladimir

Stem cell-derived tyrosine kinase (STK) is a transmembrane receptor reported to play a role in macrophage switching from a classically activated/proinflammatory phenotype to an alternatively activated/wound repair phenotype. In the present studies, STK{sup −/−} mice were used to assess the role of STK in acetaminophen-induced hepatotoxicity as evidence suggests that the pathogenic process involves both of these macrophage subpopulations. In wild type mice, centrilobular hepatic necrosis and increases in serum transaminase levels were observed within 6 h of acetaminophen administration (300 mg/kg, i.p.). Loss of STK resulted in a significant increase in sensitivity of mice to the hepatotoxic effects ofmore » acetaminophen and increased mortality, effects independent of its metabolism. This was associated with reduced levels of hepatic glutathione, rapid upregulation of inducible nitric oxide synthase, and prolonged induction of heme oxygenase-1, suggesting excessive oxidative stress in STK{sup −/−} mice. F4/80, a marker of mature macrophages, was highly expressed on subpopulations of Kupffer cells in livers of wild type, but not STK{sup −/−} mice. Whereas F4/80{sup +} macrophages rapidly declined in the livers of wild type mice following acetaminophen intoxication, they increased in STK{sup −/−} mice. In wild type mice hepatic expression of tumor necrosis factor (TNF)-α, interleukin (IL)-1β, and IL-12, products of classically activated macrophages, increased after acetaminophen administration. Monocyte chemotactic protein-1 (MCP-1) and its receptor, CCR2, as well as IL-10, mediators involved in recruiting and activating anti-inflammatory/wound repair macrophages, also increased in wild type mice after acetaminophen. Loss of STK blunted the effects of acetaminophen on expression of TNFα, IL-1β, IL-12, MCP-1 and CCR2, while expression of IL-10 increased. Hepatic expression of CX3CL1, and its receptor, CX3CR1 also increased in STK{sup −/−} mice treated with acetaminophen. These data demonstrate that STK plays a role in regulating macrophage recruitment and activation in the liver following acetaminophen administration, and in hepatotoxicity. -- Highlights: ► STK regulates alternative macrophage activation after acetaminophen intoxication. ► Loss of STK results in increased sensitivity to acetaminophen. ► Increased toxicity involves oxidative stress and decreases in repair macrophages.« less

An evaluation of a rapid real time polymerase chain reaction assay for detection of group B streptococcus as part of a neonatal group B streptococcus prevention strategy.

PubMed

Money, Deborah; Dobson, Simon; Cole, Lesley; Karacabeyli, Eda; Blondel-Hill, Edith; Milner, Ruth; Thomas, Eva

2008-09-01

To evaluate the sensitivity, specificity, and feasibility of a rapid real-time polymerase chain reaction (PCR) test for group B streptococcus (GBS) completed during labour, compared with the standard culture test performed at 35 to 37 weeks' gestation. Women presenting to the maternity unit for term vaginal delivery had two vaginal/rectal samples collected. One swab was tested using a rapid PCR method (IDI-Strep B, Infectio Diagnostic [IDI] Inc., Sainte-Foy QC ), and the other was cultured after enrichment (intrapartum culture). Comparisons were made between these results and those of a culture-based screen at 35 to 37 weeks' gestation. Of the 190 women enrolled, 85% had results of the standard screen at 35 to 37 weeks available for comparison. The sensitivity and specificity of the standard 35- to 37-week screen were 84.3% (95% confidence interval [CI], 71.4-93.0) and 93.2% (95% CI 86.5-97.2) respectively, whereas the sensitivity and specificity of the rapid PCR were 90.7% (95% CI 79.7-96.9) and 97.6% (95% CI 93.1-99.5), respectively. The median reporting time for the rapid PCR test was 99 minutes (range 50-255). Results were available more than four hours before delivery in 81% of cases. In this Canadian centre, a rapid PCR test done at the time of labour (IDI-Strep B) demonstrated high sensitivity and specificity, comparable to the 35- to 37-week screen. The time to reporting results was acceptably short, allowing for timely administration of intrapartum prophylactic antibiotics.

Contribution of Kinetic Characteristics of Axillary Lymph Nodes to the Diagnosis in Breast Magnetic Resonance Imaging

PubMed Central

Örgüç, Şebnem; Başara, Işıl; Pekindil, Gökhan; Coşkun, Teoman

2012-01-01

Objective: To assess the contribution of kinetic characteristics in the discrimination of malignant-benign axillary lymph nodes. Material and Methods: One hundred fifty-five female patients were included in the study. Following magnetic resonance imaging (MRI) examinations postprocessing applications were applied, dynamic curves were obtained from subtracted images. Types of dynamic curves were correlated with histopathological results in malignant cases or final clinical results in patients with no evidence of malignancy. Sensitivity, specificity, positive likehood ratio (+LHR), negative (−LHR) of dynamic curves characterizing the axillary lymph nodes were calculated. Results: A total of 178 lymph nodes greater than 8 mm were evaluated in 113 patients. Forty-six lymph nodes in 24 cases had malignant axillary involvement. 132 lymph nodes in 89 patients with benign diagnosis were included in the study. The sensitivity of type 3 curve as an indicator of malignancy was calculated as 89%. However the specificity, +LHR, −LHR were calculated as 14%, 1.04, 0.76 respectively. Conclusion: Since kinetic analysis of both benign and malignant axillary lymph nodes, rapid enhancement and washout (type 3) they cannot be used as a discriminator, unlike breast lesions. MRI, depending on the kinetic features of the axillary lymph nodes, is not high enough to be used in the clinical management of breast cancer patients. PMID:25207016

[Evaluation of Mascia Brunelli rapid antigen test in the diagnosis of group A streptococcal pharyngitis].

PubMed

Barış, Ayşe; Anlıaçık, Nur; Bulut, Mehmet Emin; Deniz, Rıdvan; Yücel, Elif; Aktaş, Elif

2017-01-01

Pharyngitis in most cases is due to viral microorganisms however drug therapy without the detection of etiological agent leads to unnecessary use of antibiotics. On the other hand, when the etiologic agent is group A beta-hemolytic streptococci (GAS) it is important to identify the etiologic agent rapidly which will guide the treatment with appropriate antibiotics. The use of highly sensitive rapid tests will contribute significantly to early diagnosis and appropriate therapy. The aim of this study is to evaluate the efficacy of Mascia Brunelli rapid antigen test for the detection of GAS in throat swab samples. A total of 833 throat swab samples submitted to our laboratory with pre-diagnosis of pharyngitis were assessed between June 2016 and August 2016. The samples were simultaneously cultured and tested by rapid Mascia Brunelli Strep-A Card (Mascia Brunelli S.p.a, Italy). For identification, bacitracin sensitivity, PYR test and latex agglutination test in addition to Bruker MALDI-TOF MS (Daltonics, Germany) system were used. The density of GAS growth in the culture was noted. The samples that were false negative with Mascia Brunelli test were re-tested with QuickVue + Strep A Test (Quidel Corporation, San Diego, USA) rapid antigen test. A total of 833 patients, 376 (45.2%) female and 457 (54.8%) male were included in the study. The age range was between 0-94 years with a mean value of 7.86 ± 6.72. 125 (15%) and 94 (11.28%) of the samples were positive with culture and rapid antigen test, respectively. Mascia Brunelli antigen test gave negative results for 31 culture positive samples. Of these 31 samples, 28 were found positive by QuickVue + Strep A antigen test. As a result, the sensitivity of the test was found to be independent of the inoculum effect. The culture positivity rate in patients between 5-15 years was 18.4%. The sensitivity, specificity, positive predictive value, negative predictive value and the accuracy of Mascia Brunelli antigen test, with respect to culture, were 75.2%, 100%, 100%, 95.81% and 96.28%, respectively. In conclusion, the selection of rapid antigen tests with high sensitivity in the diagnosis of GAS pharyngitis will contribute to the prevention of resistance development by appropriate use of antibiotics as well as early diagnosis and appropriate treatment. However, confirmation of negative rapid antigen test results by culture is very important in terms of false diagnosis and prevention of incomplete treatment.

Rapid detection of Pseudomonas aeruginosa targeting the toxA gene in intensive care unit patients from Beijing, China

PubMed Central

Dong, Derong; Zou, Dayang; Liu, Hui; Yang, Zhan; Huang, Simo; Liu, Ningwei; He, Xiaoming; Liu, Wei; Huang, Liuyu

2015-01-01

Pseudomonas aeruginosa is a major opportunistic pathogen in hospital-acquired infections and exhibits increasing antibiotic resistance. A rapid and sensitive molecular method for its detection in clinical samples is needed to guide therapeutic treatment and to control P. aeruginosa outbreaks. In this study, we established a polymerase spiral reaction (PSR) method for rapid detection of P. aeruginosa by targeting the toxA gene, which regulates exotoxin A synthesis. Real-time turbidity monitoring and a chromogenic visualization using hydroxynaphthol blue were used to assess the reaction. All 17 non- P. aeruginosa strains tested negative, indicating the high specificity of the PSR primers. The detection limit was 2.3 pg/μl within 60 min at isothermal temperature (65°C), 10-fold more sensitive than conventional PCR. Then, the PSR assay was applied to a clinical surveillance of P. aeruginosa in three top hospitals in Beijing, China. Of the 130 sputum samples collected from ICU patients with suspected multi-resistant infections, 37 P. aeruginosa isolates were identified from the positive samples. All clinical strains belonged to 10 different P. aeruginosa multilocus sequence typing groups and exhibited high resistance to carbapenems, cephalosporins, and aminoglycosides. Interestingly, of the 33 imipenem-resistant isolates, 30 (90.9%) had lost the outer membrane porin oprD gene. Moreover, isolate SY-95, containing multiple antibiotic resistance genes, possessed the ability to hydrolyze all antibiotics used in clinic and was susceptible only to polymyxin B. Our study showed the high level of antibiotic resistance and co-occurrence of resistance genes in the clinical strains, indicating a rapid and continuing evolution of P. aeruginosa. In conclusion, we developed a P. aeruginosa PSR assay, which could be a useful tool for clinical screening, especially in case of poor resources, or for point-of-care testing. PMID:26500639

Recent Progresses in Nanobiosensing for Food Safety Analysis

PubMed Central

Yang, Tao; Huang, Huifen; Zhu, Fang; Lin, Qinlu; Zhang, Lin; Liu, Junwen

2016-01-01

With increasing adulteration, food safety analysis has become an important research field. Nanomaterials-based biosensing holds great potential in designing highly sensitive and selective detection strategies necessary for food safety analysis. This review summarizes various function types of nanomaterials, the methods of functionalization of nanomaterials, and recent (2014–present) progress in the design and development of nanobiosensing for the detection of food contaminants including pathogens, toxins, pesticides, antibiotics, metal contaminants, and other analytes, which are sub-classified according to various recognition methods of each analyte. The existing shortcomings and future perspectives of the rapidly growing field of nanobiosensing addressing food safety issues are also discussed briefly. PMID:27447636

Infrared near-field spectroscopy of trace explosives using an external cavity quantum cascade laser.

PubMed

Craig, Ian M; Taubman, Matthew S; Lea, A Scott; Phillips, Mark C; Josberger, Erik E; Raschke, Markus B

2013-12-16

Utilizing a broadly-tunable external cavity quantum cascade laser for scattering-type scanning near-field optical microscopy (s-SNOM), we measure infrared spectra of particles of explosives by probing characteristic nitro-group resonances in the 7.1-7.9 µm wavelength range. Measurements are presented with spectral resolution of 0.25 cm(-1), spatial resolution of 25 nm, sensitivity better than 100 attomoles, and at a rapid acquisition time of 90 s per spectrum. We demonstrate high reproducibility of the acquired s-SNOM spectra with very high signal-to-noise ratios and relative noise of <0.02 in self-homodyne detection.

Health care innovation: progress report and focus on biotechnology.

PubMed

Read, J L; Lee, K B

1994-01-01

Funding for biomedical research has shifted from government to the private sector. One reason is rapid expansion in the number and strength of U.S. biotechnology companies, which collectively spend more than $6 billion a year on biomedical research. Most of these companies are not yet profitable and therefore depend on flows of capital from private investors, Wall Street, and large pharmaceutical company collaborations. Investment in the new drugs, devices, and vaccines in this pipeline is sensitive to signals emanating from the debate on health care reform, suggesting that new federal policy will have a major impact on steering the type of innovation to emerge in the future.

Recent Progresses in Nanobiosensing for Food Safety Analysis.

PubMed

Yang, Tao; Huang, Huifen; Zhu, Fang; Lin, Qinlu; Zhang, Lin; Liu, Junwen

2016-07-19

With increasing adulteration, food safety analysis has become an important research field. Nanomaterials-based biosensing holds great potential in designing highly sensitive and selective detection strategies necessary for food safety analysis. This review summarizes various function types of nanomaterials, the methods of functionalization of nanomaterials, and recent (2014-present) progress in the design and development of nanobiosensing for the detection of food contaminants including pathogens, toxins, pesticides, antibiotics, metal contaminants, and other analytes, which are sub-classified according to various recognition methods of each analyte. The existing shortcomings and future perspectives of the rapidly growing field of nanobiosensing addressing food safety issues are also discussed briefly.

Rapid, Efficient Detection and Drug Susceptibility Testing of Mycobacterium tuberculosis in Sputum by Microscopic Observation of Broth Cultures

PubMed Central

Caviedes, Luz; Lee, Tien-Shun; Gilman, Robert H.; Sheen, Patricia; Spellman, Emily; Lee, Ellen H.; Berg, Douglas E.; Montenegro-James, Sonia

2000-01-01

Inexpensive, rapid, and reliable methods of detecting infection by and drug susceptibility of Mycobacterium tuberculosis (MTB) are crucial to the control of tuberculosis. The novel microscopic observation broth-drug susceptibility assay (MODS) detects early growth of MTB in liquid medium, allowing more timely diagnosis and drug susceptibility testing. Sputum samples from hospitalized patients in Peru were analyzed by using stains, culture, and PCR. Sensitivity of MODS (92%) compared favorably with the most sensitive of the other culture methods (93%). Sputum samples positive for tuberculosis were tested for susceptibility to isoniazid and rifampin with the microwell alamar blue assay (MABA) and MODS. In 89% of cases, there was concordance between MODS and MABA. Of the diagnostic and susceptibility testing methods used, MODS yielded results most rapidly (median, 9.0 and 9.5 days, respectively). MODS is a rapid, inexpensive, sensitive, and specific method for MTB detection and susceptibility testing; it is particularly appropriate for use in developing countries burdened by significant infection rates and increasing numbers of multiple-drug-resistant cases. PMID:10699023

Rapid, efficient detection and drug susceptibility testing of Mycobacterium tuberculosis in sputum by microscopic observation of broth cultures. The Tuberculosis Working Group in Peru.

PubMed

Caviedes, L; Lee, T S; Gilman, R H; Sheen, P; Spellman, E; Lee, E H; Berg, D E; Montenegro-James, S

2000-03-01

Inexpensive, rapid, and reliable methods of detecting infection by and drug susceptibility of Mycobacterium tuberculosis (MTB) are crucial to the control of tuberculosis. The novel microscopic observation broth-drug susceptibility assay (MODS) detects early growth of MTB in liquid medium, allowing more timely diagnosis and drug susceptibility testing. Sputum samples from hospitalized patients in Peru were analyzed by using stains, culture, and PCR. Sensitivity of MODS (92%) compared favorably with the most sensitive of the other culture methods (93%). Sputum samples positive for tuberculosis were tested for susceptibility to isoniazid and rifampin with the microwell alamar blue assay (MABA) and MODS. In 89% of cases, there was concordance between MODS and MABA. Of the diagnostic and susceptibility testing methods used, MODS yielded results most rapidly (median, 9.0 and 9.5 days, respectively). MODS is a rapid, inexpensive, sensitive, and specific method for MTB detection and susceptibility testing; it is particularly appropriate for use in developing countries burdened by significant infection rates and increasing numbers of multiple-drug-resistant cases.

Using a Dynamic Global Vegetation Model to Simulate the Response of Vegetation to Warming at the Paleocene-Eocene Boundary

NASA Astrophysics Data System (ADS)

Shellito, C. J.; Sloan, L. C.

2004-12-01

A major turnover in benthic marine and terrestrial fauna marks the Initial Eocene Thermal Maximum (IETM) (~55Ma), a period of ~150 ky in which there was a rapid rise in deep sea and high latitude sea surface temperatures by 5-8C. Curiously, no major responses to this warming in the terrestrial floral record have been detected to date. Here, we present results from experiments examining the response of the global distribution of vegetation to changes in climate at the IETM using the NCAR Land Surface Model (LSM1.2) integrated with a dynamic global vegetation model (DGVM). DGVMs allow vegetation to respond to and interact with climate, and thus, provide a unique new method for addressing questions regarding feedbacks between the ecosystem and climate in Earth's past. However, there are a number of drawbacks to using these models that can affect interpretation of results. More specifically, these drawbacks involve uncertainties in the application of modern plant functional types to paleo-flora simulations, inaccuracies in the model climatology used to drive the DGVM, and lack of available detail regarding paleo-geography and paleo-soil type for use in model boundary conditions. For a better understanding of these drawbacks, we present results from a series of tests in the NCAR LSM-DGVM which examine (1) the effect of removing C4 grasses from the available plant functional types in the model; (2) model sensitivity to a change in soil texture; and (3), model sensitivity to a change in the value of pCO2 used in the photosynthetic rate equations. We consider our DGVM results for the IETM in light of output from these sensitivity experiments.

Diagnostic and prognostic value of human prion detection in cerebrospinal fluid.

PubMed

Foutz, Aaron; Appleby, Brian S; Hamlin, Clive; Liu, Xiaoqin; Yang, Sheng; Cohen, Yvonne; Chen, Wei; Blevins, Janis; Fausett, Cameron; Wang, Han; Gambetti, Pierluigi; Zhang, Shulin; Hughson, Andrew; Tatsuoka, Curtis; Schonberger, Lawrence B; Cohen, Mark L; Caughey, Byron; Safar, Jiri G

2017-01-01

Several prion amplification systems have been proposed for detection of prions in cerebrospinal fluid (CSF), most recently, the measurements of prion seeding activity with second-generation real-time quaking-induced conversion (RT-QuIC). The objective of this study was to investigate the diagnostic performance of the RT-QuIC prion test in the broad phenotypic spectrum of prion diseases. We performed CSF RT-QuIC testing in 2,141 patients who had rapidly progressive neurological disorders, determined diagnostic sensitivity and specificity in 272 cases that were autopsied, and evaluated the impact of mutations and polymorphisms in the PRNP gene, and type 1 or type 2 human prions on diagnostic performance. The 98.5% diagnostic specificity and 92% sensitivity of CSF RT-QuIC in a blinded retrospective analysis matched the 100% specificity and 95% sensitivity of a blind prospective study. The CSF RT-QuIC differentiated 94% of cases of sporadic Creutzfeldt-Jakob disease (sCJD) MM1 from the sCJD MM2 phenotype, and 80% of sCJD VV2 from sCJD VV1. The mixed prion type 1-2 and cases heterozygous for codon 129 generated intermediate CSF RT-QuIC patterns, whereas genetic prion diseases revealed distinct profiles for each PRNP gene mutation. The diagnostic performance of the improved CSF RT-QuIC is superior to surrogate marker tests for prion diseases such as 14-3-3 and tau proteins, and together with PRNP gene sequencing the test allows the major prion subtypes to be differentiated in vivo. This differentiation facilitates prediction of the clinicopathological phenotype and duration of the disease-two important considerations for envisioned therapeutic interventions. ANN NEUROL 2017;81:79-92. © 2016 American Neurological Association.

Diagnostic and Prognostic Value of Human Prion Detection in Cerebrospinal Fluid

PubMed Central

Foutz, Aaron; Appleby, Brian S.; Hamlin, Clive; Liu, Xiaoqin; Yang, Sheng; Cohen, Yvonne; Chen, Wei; Blevins, Janis; Fausett, Cameron; Wang, Han; Gambetti, Pierluigi; Zhang, Shulin; Hughson, Andrew; Tatsuoka, Curtis; Schonberger, Lawrence B.; Cohen, Mark L.; Caughey, Byron; Safar, Jiri G.

2016-01-01

Objective Several prion amplification systems have been proposed for detection of prions in cerebrospinal fluid (CSF), most recently, the measurements of prion seeding activity with second-generation real-time quaking-induced conversion (RT-QuIC). The objective of this study was to investigate the diagnostic performance of the RT-QuIC prion test in the broad phenotypic spectrum of prion diseases. Methods We performed CSF RT-QuIC testing in 2,141 patients who had rapidly progressive neurological disorders, determined diagnostic sensitivity and specificity in 272 cases which were autopsied, and evaluated the impact of mutations and polymorphisms in the PRNP gene, and Type 1 or Type 2 of human prions on diagnostic performance. Results The 98.5% diagnostic specificity and 92% sensitivity of CSF RT-QuIC in a blinded retrospective analysis matched the 100% specificity and 95% sensitivity of a blind prospective study. The CSF RT-QuIC differentiated 94% of cases of sporadic Creutzfeldt-Jakob disease (sCJD) MM1 from the sCJD MM2 phenotype, and 80% of sCJD VV2 from sCJD VV1. The mixed prion type 1–2 and cases heterozygous for codon 129 generated intermediate CSF RT-QuIC patterns, while genetic prion diseases revealed distinct profiles for each PRNP gene mutation. Interpretation The diagnostic performance of the improved CSF RT-QuIC is superior to surrogate marker tests for prion diseases such as 14-3-3 and Tau proteins and together with PRNP gene sequencing, the test allows the major prion subtypes to be differentiated in vivo. This differentiation facilitates prediction of the clinicopathological phenotype and duration of the disease—two important considerations for envisioned therapeutic interventions. PMID:27893164

Rapid screening for human-pathogenic Mucorales using rolling circle amplification.

PubMed

Dolatabadi, S; Najafzadeh, M J; de Hoog, G S

2014-12-01

Mucormycosis has emerged as a relatively common severe mycosis in patients with haematological and allogeneic stem cell transplantation. Source of transmission is from unidentified sources in the environment. Early diagnosis of infection and its source of contamination are paramount for rapid and appropriate therapy. In this study, rolling circle amplification (RCA) is introduced as a sensitive, specific and reproducible isothermal DNA amplification technique for rapid molecular identification of six of the most virulent species (Rhizopus microsporus, R. arrhizus var. arrhizus, R. arrhizus var. delemar, Mucor irregularis, Mucor circinelloides, Lichtheimia ramosa, Lichtheimia corymbifera). DNAs of target species were successfully amplified, with no cross reactivity between species. RCA can be considered as a rapid detection method with high specificity and sensitivity, suitable for large screening. © 2014 Blackwell Verlag GmbH.

Multicentre evaluations of two new rapid IgG4 tests (WB rapid and panLF rapid) for detection of lymphatic filariasis

PubMed Central

Noordin, Rahmah; Itoh, Makoto; Kimura, Eisaku; Abdul Rahman, Rohana; Ravindran, Balachandran; Mahmud, Rohela; Supali, Taniawati; Weerasooriya, Mirani

2007-01-01

In the global effort to eliminate lymphatic filariasis (LF), rapid field-applicable tests are useful tools that will allow on-site testing to be performed in remote places and the results to be obtained rapidly. Exclusive reliance on the few existing tests may jeopardize the progress of the LF elimination program, thus the introduction of other rapid tests would be useful to address this issue. Two new rapid immunochromatographic IgG4 cassette tests have been produced, namely WB rapid and panLF rapid, for detection of bancroftian filariasis and all three species of lymphatic filaria respectively. WB rapid was developed using BmSXP recombinant antigen, while PanLF rapid was developed using BmR1 and BmSXP recombinant antigens. A total of 165 WB rapid and 276 panLF rapid tests respectively were evaluated at USM and the rest were couriered to another university in Malaysia (98 WB rapid, 129 panLF rapid) and to universities in Indonesia (56 WB rapid, 62 panLF rapid), Japan (152 of each test) and India (18 of each test) where each of the tests underwent independent evaluations in a blinded manner. The average sensitivities of WB rapid and panLF rapid were found to be 97.6% (94%–100%) and 96.5% (94%–100%) respectively; while their average specificities were both 99.6% (99%–100%). Thus this study demonstrated that both the IgG4 rapid tests were highly sensitive and specific, and would be useful additional tests to facilitate the global drive to eliminate this disease. PMID:17961262

High Resolution Melting (HRM) applied to wine authenticity.

PubMed

Pereira, Leonor; Gomes, Sónia; Castro, Cláudia; Eiras-Dias, José Eduardo; Brazão, João; Graça, António; Fernandes, José R; Martins-Lopes, Paula

2017-02-01

Wine authenticity methods are in increasing demand mainly in Denomination of Origin designations. The DNA-based methodologies are a reliable means of tracking food/wine varietal composition. The main aim of this work was the study of High Resolution Melting (HRM) application as a screening method for must and wine authenticity. Three sample types (leaf, must and wine) were used to validate the three developed HRM assays (Vv1-705bp; Vv2-375bp; and Vv3-119bp). The Vv1 HRM assay was only successful when applied to leaf and must samples. The Vv2 HRM assay successfully amplified all sample types, allowing genotype discrimination based on melting temperature values. The smallest amplicon, Vv3, produced a coincident melting curve shape in all sample types (leaf and wine) with corresponding genotypes. This study presents sensitive, rapid and efficient HRM assays applied for the first time to wine samples suitable for wine authenticity purposes. Copyright © 2016 Elsevier Ltd. All rights reserved.

Quantification of simian immunodeficiency virus cytotoxic T lymphocyte escape mutant viruses.

PubMed

Loh, Liyen; Kent, Stephen J

2008-08-01

Escape from cytotoxic T-lymphocyte (CTL) pressure is common in HIV-1 infection of humans and simian immunodeficiency virus (SIV) infections of macaques. CTL escape typically incurs a fitness cost as reversion back to wild-type can occur upon transmission. We utilized sequence-specific primers and DNA probes with real-time polymerase chain reaction (PCR) to sensitively and specifically track wild-type and escape mutant viremia at the Mane-A*17-restricted SIV Gag(371379) epitope AF9 in pigtail macaques. The generation of minor escape mutant populations is detected by the real-time PCR 2 weeks earlier than observed using standard sequencing techniques. We passaged the AF9 CTL escape mutant virus into two naïve Mane-A*17-negative pigtail macaques and showed that reversion to wild-type was rapid during acute infection and then slowed considerably at later stages of the infection. These data help refine our understanding of how CTL escape mutant viruses evolve.

Inactivation of human and simian rotaviruses by chlorine dioxide

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

Chen, Yu-Shiaw; Vaughn, J.M.

1990-05-01

The inactivation of single-particle stocks of human (type 2, Wa) and simian (SA-11) rotaviruses by chlorine dioxide was investigated. Experiments were conducted at 4{degree}C in a standard phosphate-carbonate buffer. Both virus types were rapidly inactivated, within 20 s under alkaline conditions, when chlorine dioxide concentrations ranging from 0.05 to 0.2 mg/liter were used. Similar reductions of 10{sup 5}-fold in infectivity required additional exposure time of 120 s at 0.2 mg/liter for Wa and at 0.5 mg/liter for SA-11, respectively, at pH 6.0. The inactivation of both virus types was moderate a neutral pH, and the sensitivities to chlorine dioxide weremore » similar. The observed enhancement of virucidal efficiency with increasing pH was contrary to earlier findings with chlorine- and ozone-treated rotavirus particles, where efficiencies decreased with increasing alkalinity. Comparison of 99.9% virus inactivation times revealed ozone to be the most effective virucidal agent among these three disinfectants.« less

Automated cell-type classification in intact tissues by single-cell molecular profiling

PubMed Central

2018-01-01

A major challenge in biology is identifying distinct cell classes and mapping their interactions in vivo. Tissue-dissociative technologies enable deep single cell molecular profiling but do not provide spatial information. We developed a proximity ligation in situ hybridization technology (PLISH) with exceptional signal strength, specificity, and sensitivity in tissue. Multiplexed data sets can be acquired using barcoded probes and rapid label-image-erase cycles, with automated calculation of single cell profiles, enabling clustering and anatomical re-mapping of cells. We apply PLISH to expression profile ~2900 cells in intact mouse lung, which identifies and localizes known cell types, including rare ones. Unsupervised classification of the cells indicates differential expression of ‘housekeeping’ genes between cell types, and re-mapping of two sub-classes of Club cells highlights their segregated spatial domains in terminal airways. By enabling single cell profiling of various RNA species in situ, PLISH can impact many areas of basic and medical research. PMID:29319504

Rapid concentration and sensitive detection of hookworm ova from wastewater matrices using a real-time PCR method.

PubMed

Gyawali, P; Sidhu, J P S; Ahmed, W; Jagals, P; Toze, S

2015-12-01

The risk of human hookworm infections from land application of wastewater matrices could be high in regions with high hookworm prevalence. A rapid, sensitive and specific hookworm detection method from wastewater matrices is required in order to assess human health risks. Currently available methods used to identify hookworm ova to the species level are time consuming and lack accuracy. In this study, a real-time PCR method was developed for the rapid, sensitive and specific detection of canine hookworm (Ancylostoma caninum) ova from wastewater matrices. A. caninum was chosen because of its morphological similarity to the human hookworm (Ancylostoma duodenale and Necator americanus). The newly developed PCR method has high detection sensitivity with the ability to detect less than one A. caninum ova from 1 L of secondary treated wastewater at the mean threshold cycle (CT) values ranging from 30.1 to 34.3. The method is also able to detect four A. caninum ova from 1 L of raw wastewater and from ∼4 g of treated sludge with mean CT values ranging from 35.6 to 39.8 and 39.8 to 39.9, respectively. The better detection sensitivity obtained for secondary treated wastewater compared to raw wastewater and sludge samples could be attributed to sample turbidity. The proposed method appears to be rapid, sensitive and specific compared to traditional methods and has potential to aid in the public health risk assessment associated with land application of wastewater matrices. Furthermore, the method can be adapted to detect other helminth ova of interest from wastewater matrices. Crown Copyright © 2015. Published by Elsevier Inc. All rights reserved.

Performance and diagnostic usefulness of commercially available enzyme linked immunosorbent assay and rapid kits for detection of HIV, HBV and HCV in India.

PubMed

Maity, Susmita; Nandi, Srijita; Biswas, Subrata; Sadhukhan, Salil Kumar; Saha, Malay Kumar

2012-11-26

HIV, HBV and HCV pose a major public health problem throughout the world. Detection of infection markers for these agents is a major challenge for testing laboratories in a resource poor setting. As blood transfusion is an important activity saving millions of live every year, it also carries a risk of transfusion transmissible infections caused by these fatal blood borne pathogens if the quality of testing is compromised. Conventional ELISA is regarded as the mostly used screening technique but due to limitations like high cost, unavailability in many blood banks and testing sites, involvement of costly instruments, time taking nature and requirement of highly skilled personnel for interpretation, rapid tests are gaining more importance and warrants comparison of performance. A comparative study between these two techniques has been performed using commercially available diagnostic kits to assess their efficacy for detection of HIV, HBV and HCV infections. Rapid kits were more efficient in specificity with synthetic antigens along with high PPV than ELISA in most cases. Comparison between different ELISA kits revealed that Microlisa HIV and Hepalisa (J. Mitra & Co. Pvt. Ltd.); ERBA LISA HIV1 + 2, ERBA LISA Hepatitis B and ERBA LISA HCV (Transasia Bio-medicals Ltd.) gives uniform result with good performance in terms of sensitivity, specificity, PPV, NPV and efficiency, whereas, Microlisa HCV (J. Mitra & Co. Pvt. Ltd.), Microscreen HBsAg ELISA and INNOVA HCV (Span Diagnostics Ltd.) did not perform well. Rapid kits were also having high degree of sensitivity and specificity (100%) except in HIV Comb and HCV Comb (J. Mitra & Co. Pvt. Ltd.). The kit efficiency didn't vary significantly among different companies and lots in all the cases except for HCV ELISA showing statistically significant variation (p < 0.01) among three kit types. ELISA is a good screening assay for markers of HIV, HBV and HCV infections. Rapid tests are useful for further detection of false positive samples. ELISA seems the appropriate assay in blood bank. For availability of quality commercial diagnostic assays, evaluation of kit may be helpful.

Performance and diagnostic usefulness of commercially available enzyme linked immunosorbent assay and rapid kits for detection of HIV, HBV and HCV in India

PubMed Central

2012-01-01

Background HIV, HBV and HCV pose a major public health problem throughout the world. Detection of infection markers for these agents is a major challenge for testing laboratories in a resource poor setting. As blood transfusion is an important activity saving millions of live every year, it also carries a risk of transfusion transmissible infections caused by these fatal blood borne pathogens if the quality of testing is compromised. Conventional ELISA is regarded as the mostly used screening technique but due to limitations like high cost, unavailability in many blood banks and testing sites, involvement of costly instruments, time taking nature and requirement of highly skilled personnel for interpretation, rapid tests are gaining more importance and warrants comparison of performance. Results A comparative study between these two techniques has been performed using commercially available diagnostic kits to assess their efficacy for detection of HIV, HBV and HCV infections. Rapid kits were more efficient in specificity with synthetic antigens along with high PPV than ELISA in most cases. Comparison between different ELISA kits revealed that Microlisa HIV and Hepalisa (J. Mitra & Co. Pvt. Ltd.); ERBA LISA HIV1 + 2, ERBA LISA Hepatitis B and ERBA LISA HCV (Transasia Bio-medicals Ltd.) gives uniform result with good performance in terms of sensitivity, specificity, PPV, NPV and efficiency, whereas, Microlisa HCV (J. Mitra & Co. Pvt. Ltd.), Microscreen HBsAg ELISA and INNOVA HCV (Span Diagnostics Ltd.) did not perform well. Rapid kits were also having high degree of sensitivity and specificity (100%) except in HIV Comb and HCV Comb (J. Mitra & Co. Pvt. Ltd.). The kit efficiency didn’t vary significantly among different companies and lots in all the cases except for HCV ELISA showing statistically significant variation (p < 0.01) among three kit types. Conclusions ELISA is a good screening assay for markers of HIV, HBV and HCV infections. Rapid tests are useful for further detection of false positive samples. ELISA seems the appropriate assay in blood bank. For availability of quality commercial diagnostic assays, evaluation of kit may be helpful. PMID:23181517

PCR method for the rapid detection and discrimination of Legionella spp. based on the amplification of pcs, pmtA, and 16S rRNA genes.

PubMed

Janczarek, Monika; Palusińska-Szysz, Marta

2016-05-01

Legionella bacteria are organisms of public health interest due to their ability to cause pneumonia (Legionnaires' disease) in susceptible humans and their ubiquitous presence in water supply systems. Rapid diagnosis of Legionnaires' disease allows the use of therapy specific for the disease. L. pneumophila serogroup 1 is the most common cause of infection acquired in community and hospital environments. The non-L. pneumophila infections are likely under-detected because of a lack of effective diagnosis. In this work, simplex and duplex PCR assays with the use of new molecular markers pcs and pmtA involved in phosphatidylcholine synthesis were specified for rapid and cost-efficient identification and distinguishing Legionella species. The sets of primers developed were found to be sensitive and specific for reliable detection of Legionella belonging to the eight most clinically relevant species. Among these, four primer sets I, II, VI, and VII used for duplex-PCRs proved to have the highest identification power and reliability in the detection of the bacteria. Application of this PCR-based method should improve detection of Legionella spp. in both clinical and environmental settings and facilitate molecular typing of these organisms.

Multicenter Evaluation of the Solana Group A Streptococcus Assay: Comparison with Culture.

PubMed

Uphoff, Timothy S; Buchan, Blake W; Ledeboer, Nathan A; Granato, Paul A; Daly, Judy A; Marti, Tara N

2016-09-01

We compared group A Streptococcus (GAS) culture with a rapid helicase-dependent amplification (HDA) method using 1,082 throat swab specimens. The HDA method demonstrated 98.2% sensitivity and 97.2% specificity. GAS prevalence by culture was 20.7%, and it was 22.6% using the HDA method. In 35 min, the HDA method provided rapid, sensitive GAS detection, making culture confirmation unnecessary. Copyright © 2016 Uphoff et al.

Nucleotide variation in Sabin type 2 poliovirus from an immunodeficient patient with poliomyelitis.

PubMed

Buttinelli, Gabriele; Donati, Valentina; Fiore, Stefano; Marturano, Jill; Plebani, Alessandro; Balestri, Paolo; Soresina, Anna Rosa; Vivarelli, Rossella; Delpeyroux, Francis; Martin, Javier; Fiore, Lucia

2003-05-01

The molecular and antigenic properties of a Sabin-like type 2 poliovirus, isolated from the stool samples of a 2-year-old agammaglobulinaemic child who developed paralysis 1 year after receiving the third dose of oral poliovirus vaccine, were analysed. The virus revealed 0.88 % genome variation in the VP1 region compared with the standard reference strain, compatible with replication of the virus in the intestine over approximately 1 year. The typical mutations in the 5'NCR and VP1 associated with reversion to neurovirulence for Sabin type 2 poliovirus were found. Despite this, the virus was characterized by both PCR and ELISA tests as Sabin-like and showed temperature sensitivity and neurovirulence in transgenic mice typical of the Sabin type 2 vaccine strain. Gammaglobulin replacement therapy led rapidly to virus clearance, which, when combined with treatment with the antiviral drug pleconaril, stopped virus excretion; no further virus shedding occurred. This is the first case of poliomyelitis and long-term excretion from an immunodeficient patient to be reported in Italy through the active 'Acute Flaccid Paralysis' surveillance system.

Early Sensitivity to Discourse-Level Anomalies: Evidence from Self-Paced Reading

ERIC Educational Resources Information Center

Stewart, Andrew J.; Kidd, Evan; Haigh, Matthew

2009-01-01

Two word-by-word, self-paced reading experiments investigated the speed with which readers were sensitive to discourse-level anomalies. An account arguing for delayed sensitivity (Guzman & Klin, 2000) was contrasted with one allowing for rapid sensitivity (Myers & O'Brien, 1998). Anomalies related to spatial information (Experiment 1) and…

Rapid and sensitive detection of human astrovirus in water samples by loop-mediated isothermal amplification with hydroxynaphthol blue dye

PubMed Central

2014-01-01

Background The aim of this paper was to develop a reverse transcription loop-mediated isothermal amplification (RT-LAMP) method for rapid, sensitive and inexpensive detection of astrovirus. Results The detection limit of LAMP using in vitro RNA transcripts was 3.6×10 copies·μL-1, which is as sensitive as the presently used PCR assays. However, the LAMP products could be identified as different colors with the naked eye following staining with hydroxynaphthol blue dye (HNB). No cross-reactivity with other gastroenteric viruses (rotavirus and norovirus) was observed, indicating the relatively high specificity of LAMP. The RT-LAMP method with HNB was used to effectively detect astrovirus in reclaimed water samples. Conclusions The LAMP technique described in this study is a cheap, sensitive, specific and rapid method for the detection of astrovirus. The RT-LAMP method can be simply applied for the specific detection of astrovirus and has the potential to be utilized in the field as a screening test. PMID:24524254

Facile and sensitive determination of N-nitrosamines in food samples by high-performance liquid chromatography via combining fluorescent labeling with dispersive liquid-liquid microextraction.

PubMed

Lu, Shuaimin; Wu, Di; Li, Guoliang; Lv, Zhengxian; Gong, Peiwei; Xia, Lian; Sun, Zhiwei; Chen, Guang; Chen, Xuefeng; You, Jinmao; Wu, Yongning

2017-11-01

The intake of N-nitrosamines (NAs) from foodstuffs is considered to be an important influence factor for several cancers. But the rapid and sensitive screening of NAs remains a challenge in the field of food safety. Inspired by that, a sensitive and rapid method was demonstrated for determination of five NAs (Nitrosopyrrolidine, Nitrosodimethylamine, Nitrosodiethylamine, Nitrosodipropylamine and Nitrosodibutylamine) using dispersive liquid-liquid microextraction (DLLME) followed by high-performance liquid chromatography with fluorescence detection (HPLC-FLD). The NAs were firstly denitrosated and labeled by 2-(11H-benzo[a]carbazol-11-yl) ethyl carbonochloridate (BCEC-Cl) and finally enriched by DLLME. Furthermore, the main DLLME conditions were optimized systematically. Under the optimal conditions, satisfactory limits of detection (LODs) were obtained with a range of 0.01-0.07ngg -1 , which were significantly lower than the reported methods. The developed method showed many merits including rapidity, simplicity, high sensitivity and excellent selectivity, which shows a broad prospect in food safety analysis. Copyright © 2017 Elsevier Ltd. All rights reserved.

Spin-Label CW Microwave Power Saturation and Rapid Passage with Triangular Non-Adiabatic Rapid Sweep (NARS) and Adiabatic Rapid Passage (ARP) EPR Spectroscopy

PubMed Central

Kittell, Aaron W.; Hyde, James S.

2015-01-01

Non-adiabatic rapid passage (NARS) electron paramagnetic resonance (EPR) spectroscopy was introduced by Kittell, A.W., Camenisch, T.G., Ratke, J.J. Sidabras, J.W., Hyde, J.S., 2011 as a general purpose technique to collect the pure absorption response. The technique has been used to improve sensitivity relative to sinusoidal magnetic field modulation, increase the range of inter-spin distances that can be measured under near physiological conditions, and enhance spectral resolution in copper (II) spectra. In the present work, the method is extended to CW microwave power saturation of spin-labeled T4 Lysozyme (T4L). As in the cited papers, rapid triangular sweep of the polarizing magnetic field was superimposed on slow sweep across the spectrum. Adiabatic rapid passage (ARP) effects were encountered in samples undergoing very slow rotational diffusion as the triangular magnetic field sweep rate was increased. The paper reports results of variation of experimental parameters at the interface of adiabatic and non-adiabatic rapid sweep conditions. Comparison of the forward (up) and reverse (down) triangular sweeps is shown to be a good indicator of the presence of rapid passage effects. Spectral turning points can be distinguished from spectral regions between turning points in two ways: differential microwave power saturation and differential passage effects. Oxygen accessibility data are shown under NARS conditions that appear similar to conventional field modulation data. However, the sensitivity is much higher, permitting, in principle, experiments at substantially lower protein concentrations. Spectral displays were obtained that appear sensitive to rotational diffusion in the range of rotational correlation times of 10−3 to 10−7 s in a manner that is analogous to saturation transfer spectroscopy. PMID:25917132

Superior Diagnostic Performance of Malaria Rapid Diagnostic Tests as compared to Blood Smears in U.S. Clinical Practice

PubMed Central

Stauffer, William M.; Cartwright, Charles P.; Olson, Douglas; Juni, Billie Anne; Taylor, Charlotte M; Bowers, Susan H.; Hanson, Kevan L.; Rosenblatt, Jon E.; Boulware, David R.

2010-01-01

Background Approximately 4 million U.S. travelers to developing countries are ill enough to seek healthcare with 1,500 malaria cases reported in the U.S. annually. The diagnosis of malaria is frequently delayed due to the time to prepare malaria blood films and lack of technical expertise. An easy, reliable rapid diagnostic test (RDT) with high sensitivity and negative predictive value (NPV), particularly for Plasmodium falciparum, would be clinically useful. The study objective was to determine the diagnostic performance of the FDA-approved NOW® Malaria Test in comparison to traditional thick and thin blood smears for malaria diagnosis. Methods This prospective study tested 852 consecutive blood samples sent for thick and thin smears with blinded, malaria rapid tests at three hospital laboratories during 2003–2006. Polymerase chain reaction (PCR) verified positive tests and discordant results. Results Malaria occurred in 11% (95/852). The rapid test had superior performance than the standard Giemsa thick blood smear (P=.003). The rapid test’s sensitivity for all malaria was 97% (92/95) vs. 85% (81/95) by blood smear, and the RDT had superior NPV of 99.6% vs. 98.2% (P=.001). The P. falciparum performance was excellent with 100% rapid test sensitivity versus only 88% (65/74) by blood smear (P=.003). Conclusions This operational study demonstrates the FDA-approved rapid malaria test is superior to a single set of blood smears performed under routine U.S. clinical laboratory conditions. The most valuable clinical role of the RDT is in the rapid diagnosis or the exclusion of P. falciparum malaria, which is particularly useful in outpatient settings when evaluating febrile travelers. PMID:19686072

Development of chemiluminescent probe hybridization, RT-PCR and nucleic acid cycle sequencing assays of Sabin type 3 isolates to identify base pair 472 Sabin type 3 mutants associated with vaccine associated paralytic poliomyelitis.

PubMed

Old, M O; Logan, L H; Maldonado, Y A

1997-11-01

Sabin type 3 polio vaccine virus is the most common cause of poliovaccine associated paralytic poliomyelitis. Vaccine associated paralytic poliomyelitis cases have been associated with Sabin type 3 revertants containing a single U to C substitution at bp 472 of Sabin type 3. A rapid method of identification of Sabin type 3 bp 472 mutants is described. An enterovirus group-specific probe for use in a chemiluminescent dot blot hybridization assay was developed to identify enterovirus positive viral lysates. A reverse transcription-polymerase chain reaction (RT-PCR) assay producing a 319 bp PCR product containing the Sabin type 3 bp 472 mutation site was then employed to identify Sabin type 3 isolates. Chemiluminescent nucleic acid cycle sequencing of the purified 319 bp PCR product was then employed to identify nucleic acid sequences at bp 472. The enterovirus group probe hybridization procedure and isolation of the Sabin type 3 PCR product were highly sensitive and specific; nucleic acid cycle sequencing corresponded to the known sequence of stock Sabin type 3 isolates. These methods will be used to identify the Sabin type 3 reversion rate from sequential stool samples of infants obtained after the first and second doses of oral poliovirus vaccine.

Rapid antigen detection test for group A streptococcus in children with pharyngitis.

PubMed

Cohen, Jérémie F; Bertille, Nathalie; Cohen, Robert; Chalumeau, Martin

2016-07-04

Group A streptococcus (GAS) accounts for 20% to 40% of cases of pharyngitis in children; the remaining cases are caused by viruses. Compared with throat culture, rapid antigen detection tests (RADTs) offer diagnosis at the point of care (within five to 10 minutes). To determine the diagnostic accuracy of RADTs for diagnosing GAS in children with pharyngitis. To assess the relative diagnostic accuracy of the two major types of RADTs (enzyme immunoassays (EIA) and optical immunoassays (OIA)) by indirect and direct comparison. We searched CENTRAL, MEDLINE, EMBASE, Web of Science, CDSR, DARE, MEDION and TRIP (January 1980 to July 2015). We also conducted related citations tracking via PubMed, handsearched reference lists of included studies and relevant review articles, and screened all articles citing included studies via Google Scholar. We included studies that compared RADT for GAS pharyngitis with throat culture on a blood agar plate in a microbiology laboratory in children seen in ambulatory care. Two review authors independently screened titles and abstracts for relevance, assessed full texts for inclusion, and carried out data extraction and quality assessment using the QUADAS-2 tool. We used bivariate meta-analysis to estimate summary sensitivity and specificity, and to investigate heterogeneity across studies. We compared the accuracy of EIA and OIA tests using indirect and direct evidence. We included 98 unique studies in the review (116 test evaluations; 101,121 participants). The overall methodological quality of included studies was poor, mainly because many studies were at high risk of bias regarding patient selection and the reference standard used (in 73% and 43% of test evaluations, respectively). In studies in which all participants underwent both RADT and throat culture (105 test evaluations; 58,244 participants; median prevalence of participants with GAS was 29.5%), RADT had a summary sensitivity of 85.6%; 95% confidence interval (CI) 83.3 to 87.6 and a summary specificity of 95.4%; 95% CI 94.5 to 96.2. There was substantial heterogeneity in sensitivity across studies; specificity was more stable. There was no evidence of a trade-off between sensitivity and specificity. Heterogeneity in accuracy was not explained by study-level characteristics such as whether an enrichment broth was used before plating, mean age and clinical severity of participants, and GAS prevalence. The sensitivity of EIA and OIA tests was comparable (summary sensitivity 85.4% versus 86.2%). Sensitivity analyses showed that summary estimates of sensitivity and specificity were stable in low risk of bias studies. In a population of 1000 children with a GAS prevalence of 30%, 43 patients with GAS will be missed. Whether or not RADT can be used as a stand-alone test to rule out GAS will depend mainly on the epidemiological context. The sensitivity of EIA and OIA tests seems comparable. RADT specificity is sufficiently high to ensure against unnecessary use of antibiotics. Based on these results, we would expect that amongst 100 children with strep throat, 86 would be correctly detected with the rapid test while 14 would be missed and not receive antibiotic treatment.

Rapid and quantitative detection of the microbial spoilage in milk using Fourier transform infrared spectroscopy and chemometrics.

PubMed

Nicolaou, Nicoletta; Goodacre, Royston

2008-10-01

Microbiological safety plays a very significant part in the quality control of milk and dairy products worldwide. Current methods used in the detection and enumeration of spoilage bacteria in pasteurized milk in the dairy industry, although accurate and sensitive, are time-consuming. FT-IR spectroscopy is a metabolic fingerprinting technique that can potentially be used to deliver results with the same accuracy and sensitivity, within minutes after minimal sample preparation. We tested this hypothesis using attenuated total reflectance (ATR), and high throughput (HT) FT-IR techniques. Three main types of pasteurized milk - whole, semi-skimmed and skimmed - were used and milk was allowed to spoil naturally by incubation at 15 degrees C. Samples for FT-IR were obtained at frequent, fixed time intervals and pH and total viable counts were also recorded. Multivariate statistical methods, including principal components-discriminant function analysis and partial least squares regression (PLSR), were then used to investigate the relationship between metabolic fingerprints and the total viable counts. FT-IR ATR data for all milks showed reasonable results for bacterial loads above 10(5) cfu ml(-1). By contrast, FT-IR HT provided more accurate results for lower viable bacterial counts down to 10(3) cfu ml(-1) for whole milk and, 4 x 10(2) cfu ml(-1) for semi-skimmed and skimmed milk. Using FT-IR with PLSR we were able to acquire a metabolic fingerprint rapidly and quantify the microbial load of milk samples accurately, with very little sample preparation. We believe that metabolic fingerprinting using FT-IR has very good potential for future use in the dairy industry as a rapid method of detection and enumeration.

Loop-mediated isothermal amplification assay targeting the mpb70 gene for rapid differential detection of Mycobacterium bovis.

PubMed

Zhang, Hui; Wang, Zhen; Cao, Xudong; Wang, Zhengrong; Sheng, Jinliang; Wang, Yong; Zhang, Jing; Li, Zhiqiang; Gu, Xinli; Chen, Chuangfu

2016-11-01

Loop-mediated isothermal amplification (LAMP) is a highly sensitive, rapid, cost-effective nucleic acid amplification method. Tuberculosis (TB) is widely popular in the world and it is difficult to cure. The fundamental treatment is to clear the types of TB pathogens such as Mycobacterium bovis (M. bovis), Mycobacterium tuberculosis (M. tuberculosis). In order to detect and diagnose TB early, we constructed the differential diagnostic method of TB. In this study, we used LAMP for detection of M. bovis, based on amplification of the mpb70 gene which is a unique gene in M. bovis strain. The LAMP assay was able to detect only seven copies of the gene per reaction, whereas for the conventional PCR, it was 70 copies. The LAMP was evaluated for its specificity using six strains of five Mycobacterium species and 18 related non-Mycobacterium microorganism strains as controls. The target three Mycobacterium strains were all amplified, and no cross-reaction was found with 18 non-Mycobacterium microorganism strains. TB was detected by two methods, LAMP and conventional PCR (based on mpb70 gene); the positive rates of the two methods were 9.55 and 7.01 %, respectively. Our results indicate that the LAMP method should be a potential tool with high convenience, rapidity, sensitivity and specificity for the diagnosis of TB caused by M. bovis. Most importance is that the use of LAMP as diagnostic method in association with diagnostic tests based on mpb70 gene would allow the differentiation between M. bovis and other Mycobacterium in humans or animals. The LAMP method is actually in order to detect human TB, and it can be used for differential diagnosis in this paper.

ELISA-PLA: A novel hybrid platform for the rapid, highly sensitive and specific quantification of proteins and post-translational modifications.

PubMed

Tong, Qing-He; Tao, Tao; Xie, Li-Qi; Lu, Hao-Jie

2016-06-15

Detection of low-abundance proteins and their post-translational modifications (PTMs) remains a great challenge. A conventional enzyme-linked immunosorbent assay (ELISA) is not sensitive enough to detect low-abundance PTMs and suffers from nonspecific detection. Herein, a rapid, highly sensitive and specific platform integrating ELISA with a proximity ligation assay (PLA), termed ELISA-PLA, was developed. Using ELISA-PLA, the specificity was improved by the simultaneous and proximate recognition of targets through multiple probes, and the sensitivity was significantly improved by rolling circle amplification (RCA). For GFP, the limit of detection (LOD) was decreased by two orders of magnitude compared to that of ELISA. Using site-specific phospho-antibody and pan-specific phospho-antibody, ELISA-PLA was successfully applied to quantify the phosphorylation dynamics of ERK1/2 and the overall tyrosine phosphorylation level of ERK1/2, respectively. ELISA-PLA was also used to quantify the O-GlcNAcylation of AKT, c-Fos, CREB and STAT3, which is faster and more sensitive than the conventional immunoprecipitation and western blotting (IP-WB) method. As a result, the sample consumption of ELISA-PLA was reduced 40-fold compared to IP-WB. Therefore, ELISA-PLA could be a promising platform for the rapid, sensitive and specific detection of proteins and PTMs. Copyright © 2016 Elsevier B.V. All rights reserved.

Sensitivity for Diagnosing Group A Streptococcal Pharyngitis from Manufacturers is 10% Higher than Reported in Peer-Reviewed Publications.

PubMed

Vachhani, Raj; Patel, Toral; Centor, Robert M; Estrada, Carlos A

2017-01-01

Meta-analyses based on peer-reviewed publications report a sensitivity of approximately 85% for rapid antigen streptococcus tests to diagnose group A streptococcal (GAS) pharyngitis. Because these meta-analyses excluded package inserts, we examined the test characteristics of rapid antigen streptococcal tests and molecular methods that manufacturers report in their package inserts. We included tests available in the US market (Food and Drug Administration, period searched 1993-2015) and used package insert data to calculate pooled sensitivity and specificity. To examine quality, we used the Quality Assessment of Diagnostic Accuracy Studies-2. We excluded 26 tests having different trade names but identical methods and data. The study design was prospective in 41.7% (10 of 24). The pooled sensitivity of the most commonly used method, lateral flow/immunochromatographic, was 95% (95% confidence interval [CI] 94-96) and the pooled specificity was 98% (96-98); 7108 patients. The pooled sensitivity of the polymerase chain reaction or molecular methods was 98% (95% CI 96-98) and the pooled specificity was 96% (95% CI 95-97); 5685 patients. Package inserts include sponsored studies that overestimate the sensitivity of rapid tests to diagnose GAS pharyngitis by approximately 10%. Physicians should understand that package inserts overestimate diagnostic test utility; a negative test cannot be used to exclude GAS pharyngitis.

Analysis of sensitivity to different parameterization schemes for a subtropical cyclone

NASA Astrophysics Data System (ADS)

Quitián-Hernández, L.; Fernández-González, S.; González-Alemán, J. J.; Valero, F.; Martín, M. L.

2018-05-01

A sensitivity analysis to diverse WRF model physical parameterization schemes is carried out during the lifecycle of a Subtropical cyclone (STC). STCs are low-pressure systems that share tropical and extratropical characteristics, with hybrid thermal structures. In October 2014, a STC made landfall in the Canary Islands, causing widespread damage from strong winds and precipitation there. The system began to develop on October 18 and its effects lasted until October 21. Accurate simulation of this type of cyclone continues to be a major challenge because of its rapid intensification and unique characteristics. In the present study, several numerical simulations were performed using the WRF model to do a sensitivity analysis of its various parameterization schemes for the development and intensification of the STC. The combination of parameterization schemes that best simulated this type of phenomenon was thereby determined. In particular, the parameterization combinations that included the Tiedtke cumulus schemes had the most positive effects on model results. Moreover, concerning STC track validation, optimal results were attained when the STC was fully formed and all convective processes stabilized. Furthermore, to obtain the parameterization schemes that optimally categorize STC structure, a verification using Cyclone Phase Space is assessed. Consequently, the combination of parameterizations including the Tiedtke cumulus schemes were again the best in categorizing the cyclone's subtropical structure. For strength validation, related atmospheric variables such as wind speed and precipitable water were analyzed. Finally, the effects of using a deterministic or probabilistic approach in simulating intense convective phenomena were evaluated.

GREEN TEA CATECHINS ARE POTENT SENSITIZERS OF RYANODINE RECEPTOR TYPE 1 (RYR1)

PubMed Central

Feng, Wei; Cherednichenko, Gennady; Ward, Chris W.; Padilla, Isela T.; Cabrales, Elaine; Lopez, José R.; Eltit, José M.; Allen, Paul D.; Pessah, Isaac N.

2010-01-01

Catechins, polyphenols extracted from green tea leaves, have a broad range of biological activities although the specific molecular mechanisms responsible are not known. At the high experimental concentrations typically used polyphenols bind to membrane phospholipid and also are easily auto-oxidized to generate superoxide anion and semiquinones, and can adduct to protein thiols. We report that the type 1 ryanodine receptor (RyR1) is a molecular target that responds to nanomolar (−)-epigallocatechin-3-gallate (EGCG) and (−)-epicatechin-3-gallate (ECG). Single channel analyses demonstrate EGCG (5-10nM) increases channel open probability (Po) 2-fold, by lengthening open dwell time. The degree of channel activation is concentration dependent and is rapidly and fully reversible. Four related catechins, EGCG, ECG, EGC ((−)-epigallocatechin) and EC ((−)-epicatechin) showed a rank order of activity toward RyR1 (EGCG>ECG>>EGC>>>EC). EGCG and ECG enhance the sensitivity of RyR1 to activation by ≤100μM cytoplasmic Ca2+ without altering inhibitory potency by >100μM Ca2+. EGCG as high as 10μM in the extracellular medium potentiated Ca2+ transient amplitudes evoked by electrical stimuli applied to intact myotubes and adult FDB fibers, without eliciting spontaneous Ca2+ release or slowing Ca2+ transient recovery. The results identify RyR1 as a sensitive target for the major tea catechins EGCG and ECG, and this interaction is likely to contribute to their observed biological activities. PMID:20471964

Conserved features of cancer cells define their sensitivity of HAMLET-induced death; c-Myc and glycolysis

PubMed Central

Storm, Petter; Puthia, Manoj Kumar; Aits, Sonja; Urbano, Alexander; Northen, Trent; Powers, Scott; Bowen, Ben; Chao, Yinxia; Reindl, Wolfgang; Lee, Do Yup; Sullivan, Nancy Liu; Zhang, Jianping; Trulsson, Maria; Yang, Henry; Watson, James; Svanborg, Catharina

2014-01-01

HAMLET is the first member of a new family of tumoricidal protein-lipid complexes that kill cancer cells broadly, while sparing healthy, differentiated cells. Many and diverse tumor cell types are sensitive to the lethal effect, suggesting that HAMLET identifies and activates conserved death pathways in cancer cells. Here we investigated the molecular basis for the difference in sensitivity between cancer cells and healthy cells. Using a combination of small hairpin RNA inhibition, proteomic and metabolomic technology we identified the c-Myc oncogene as one essential determinant of HAMLET sensitivity. Increased c-Myc expression levels promoted the sensitivity to HAMLET and shRNA knockdown of c-Myc suppressed the lethal response, suggesting that oncogenic transformation with c-Myc creates a HAMLET-sensitive phenotype. Furthermore, the HAMLET sensitivity was modified by the glycolytic state of the tumor cells. Glucose deprivation sensitized tumor cells to HAMLET-induced cell death and in the shRNA screen Hexokinase 1, PFKFB1 and HIF1α modified HAMLET sensitivity. Hexokinase 1 was shown to bind HAMLET in a protein array containing approximately 8000 targets and Hexokinase activity decreased within 15 minutes of HAMLET treatment, prior to morphological signs of tumor cell death. In parallel, HAMLET triggered rapid metabolic paralysis in carcinoma cells. The glycolytic machinery was modified and glycolysis was shifted towards the pentose phosphate pathway. Tumor cells were also shown to contain large amounts of oleic acid and its derivatives already after 15 minutes. The results identify HAMLET as a novel anti-cancer agent that kills tumor cells by exploiting unifying features of cancer cells such as oncogene-addiction or the Warburg effect. PMID:21643007

Conserved features of cancer cells define their sensitivity to HAMLET-induced death; c-Myc and glycolysis.

PubMed

Storm, P; Aits, S; Puthia, M K; Urbano, A; Northen, T; Powers, S; Bowen, B; Chao, Y; Reindl, W; Lee, D Y; Sullivan, N L; Zhang, J; Trulsson, M; Yang, H; Watson, J D; Svanborg, C

2011-12-01

HAMLET is the first member of a new family of tumoricidal protein-lipid complexes that kill cancer cells broadly, while sparing healthy, differentiated cells. Many and diverse tumor cell types are sensitive to the lethal effect, suggesting that HAMLET identifies and activates conserved death pathways in cancer cells. Here, we investigated the molecular basis for the difference in sensitivity between cancer cells and healthy cells. Using a combination of small-hairpin RNA (shRNA) inhibition, proteomic and metabolomic technology, we identified the c-Myc oncogene as one essential determinant of HAMLET sensitivity. Increased c-Myc expression levels promoted sensitivity to HAMLET and shRNA knockdown of c-Myc suppressed the lethal response, suggesting that oncogenic transformation with c-Myc creates a HAMLET-sensitive phenotype. Furthermore, HAMLET sensitivity was modified by the glycolytic state of tumor cells. Glucose deprivation sensitized tumor cells to HAMLET-induced cell death and in the shRNA screen, hexokinase 1 (HK1), 6-phosphofructo-2-kinase/fructose-2,6-biphosphatase 1 and hypoxia-inducible factor 1α modified HAMLET sensitivity. HK1 was shown to bind HAMLET in a protein array containing ∼8000 targets, and HK activity decreased within 15 min of HAMLET treatment, before morphological signs of tumor cell death. In parallel, HAMLET triggered rapid metabolic paralysis in carcinoma cells. Tumor cells were also shown to contain large amounts of oleic acid and its derivatives already after 15 min. The results identify HAMLET as a novel anti-cancer agent that kills tumor cells by exploiting unifying features of cancer cells such as oncogene addiction or the Warburg effect.

Comparing Usual Care With a Warfarin Initiation Protocol After Mechanical Heart Valve Replacement.

PubMed

Roberts, Gregory; Razooqi, Rasha; Quinn, Stephen

2017-03-01

The immediate postoperative warfarin sensitivity for patients receiving heart valve prostheses is increased. Established warfarin initiation protocols may lack clinical applicability, resulting in dosing based on clinical judgment. To compare current practice for warfarin initiation with a known warfarin initiation protocol, with doses proportionally reduced to account for the increased postoperative sensitivity. We compared the Mechanical Heart Valve Warfarin Initiation Protocol (Protocol group) with current practice (clinical judgment-Empirical group) for patients receiving mechanical heart valves in an observational before-and-after format. End points were the time to achieve a stable therapeutic international normalized ratio (INR), doses held in the first 6 days, and overanticoagulation in the first 6 days. The Protocol group (n = 37) achieved a stable INR more rapidly than the Empirical group (n = 77; median times 5.1 and 8.7 days, respectively; P = 0.002). Multivariable analysis indicated that the Protocol group (hazard ratio [HR] = 2.22; P = 0.005) and men (HR = 1.76; P = 0.043) more rapidly achieved a stable therapeutic INR. Age, serum albumin, amiodarone, presence of severe heart failure, and surgery type had no impact. Protocol patients had fewer doses held (1.1% vs 10.1%, P < 0.001) and no difference in overanticoagulation (2.7% vs 9.1%, P = 0.27). The Mechanical Heart Valve Warfarin Initiation Protocol provided a reliable approach to initiating warfarin in patients receiving mechanical aortic or mitral valves.

Deoxyribonucleic Acid Probes Analyses for the Detection of Periodontal Pathogens.

PubMed

Al Yahfoufi, Zoubeida; Hadchiti, Wahib; Berberi, Antoine

2015-09-01

In clinical microbiology several techniques have been used to identify bacteria. Recently, Deoxyribonucleic acid (DNA)-based techniques have been introduced to detect human microbial pathogens in periodontal diseases. Deoxyribonucleic acid probes can detect bacteria at a very low level if we compared with the culture methods. These probes have shown rapid and cost-effective microbial diagnosis, good sensitivity and specificity for some periodontal pathogens in cases of severe periodontitis. Eighty-five patients were recruited for the study. Twenty-one subjects ranging between 22 and 48 years of age fulfilled the inclusion and exclusion criteria. Seventy-eight samples became available for DNA probe analysis from the deepest pockets in each quadrant. All 21 patients showed positive results for Prevotella intermedia; also, Prevotella gingivalis was identified in 19 subjects, Aggregatibacter actinomycetemcomitans in 6 subjects. P. intermedia was diagnosed positive in 82% of the subgingival samples taken, 79% for P. gingivalis, and 23% for A. actinomycetemcomitans. This study shows a high frequency of putative periodontal pathogens by using DNA probe technology, which is semi-quantitative in this study. Deoxyribonucleic acid probes can detect bacteria at very low level about 10(3) which is below the detection level of culture methods. The detection threshold of cultural methods. The three types of bacteria can be detected rapidly with high sensitivity by using the DNA probe by general practitioners, and thus can help in the diagnosis process and the treatment.

LHCSR3 affects de-coupling and re-coupling of LHCII to PSII during state transitions in Chlamydomonas reinhardtii

PubMed Central

Roach, Thomas; Na, Chae Sun

2017-01-01

Photosynthetic organisms have to tolerate rapid changes in light intensity, which is facilitated by non-photochemical quenching (NPQ) and involves modification of energy transfer from light-harvesting complexes (LHC) to the photosystem reaction centres. NPQ includes dissipating excess light energy to heat (qE) and the reversible coupling of LHCII to photosystems (state transitions/qT), which are considered separate NPQ mechanisms. In the model alga Chlamydomonas reinhardtii the LHCSR3 protein has a well characterised role in qE. Here, it is shown in the npq4 mutant, deficient in LHCSR3, that energy coupling to photosystem II (PSII) more akin to qT is also disrupted, but no major differences in LHC phosphorylation or LHC compositions were found in comparison to wild-type cells. The qT of wild-type cells possessed two kinetically distinguishable phases, with LHCSR3 participating in the more rapid (<2 min) phase. This LHCSR3-mediated qT was sensitive to physiological levels of H2O2, which accelerated qE induction, revealing a way that may help C. reinhardtii tolerate a sudden increase in light intensity. Overall, a clear mechanistic overlap between qE and qT is shown. PMID:28233792

Implementation of fluorescence confocal mosaicking microscopy by ``early adopter'' Mohs surgeons and dermatologists: recent progress

NASA Astrophysics Data System (ADS)

Jain, Manu; Rajadhyaksha, Milind; Nehal, Kishwer

2017-02-01

Confocal mosaicking microscopy (CMM) enables rapid imaging of large areas of fresh tissue ex vivo without the processing that is necessary for conventional histology. When performed in fluorescence mode using acridine orange (nuclear specific dye), it enhances nuclei-to-dermis contrast that enables detection of all types of basal cell carcinomas (BCCs), including micronodular and thin strands of infiltrative types. So far, this technique has been mostly validated in research settings for the detection of residual BCC tumor margins with high sensitivity of 89% to 96% and specificity of 99% to 89%. Recently, CMM has advanced to implementation and testing in clinical settings by "early adopter" Mohs surgeons, as an adjunct to frozen section during Mohs surgery. We summarize the development of CMM guided imaging of ex vivo skin tissues from bench to bedside. We also present its current state of application in routine clinical workflow not only for the assessment of residual BCC margins in the Mohs surgical setting but also for some melanocytic lesions and other skin conditions in clinical dermatology settings. Last, we also discuss the potential limitations of this technology as well as future developments. As this technology advances further, it may serve as an adjunct to standard histology and enable rapid surgical pathology of skin cancers at the bedside.

Ecological study of peat landforms in Canada and Alaska

NASA Technical Reports Server (NTRS)

Glaser, Paul H.

1989-01-01

Over 20 percent of the land surface of Canada and Alaska is covered by peatlands, which may be defined as any waterlogged ecosystem with a minimum thickness of 20 cm of organic matter in the soil. Past investigations have demonstrated the value of aerial photographs in identifying the major vegetation types and analyzing the biotic and hydrogeologic processes that control the development of these peatlands. In the present study, LANDSAT TM imagery was used in conjunction with field studies to determine the utility of this satellite sensor for detecting these important processes. Although the vegetation landforms within these major peat basins are visible on aerial photographs, LANDSAT TM imagery provides essential new evidence for their analysis. Spectral data from the LANDSAT TM system provides: (1) synoptic views of the patterns across large portions of these peat basins, indicating important physiographic controls on peatland development, (2) more sensitive detection of the major vegetation types, allowing rapid quantitative estimates to be made of their distribution and aerial extent, (3) discrimination of bog areas with potentially rapid or slow rates of peat accumulation, (4) identification of discharge zones for groundwater, which apparently represents the most important source of alkalinity in these peat basins, and (5) detection of flow patterns in water tracks that appear nearly uniform on standard aerial photographs.

Real-time RPA assay for rapid detection and differentiation of wild-type pseudorabies and gE-deleted vaccine viruses.

PubMed

Wang, Jianchang; Liu, Libing; Wang, Jinfeng; Pang, Xiaoyu; Yuan, Wanzhe

2018-02-15

The objective of this study was to develop a dual real-time recombinase polymerase amplification (RPA) assay using exo probes for the detection and differentiation of pseudorabies virus (PRV). Specific RPA primers and probes were designed for gB and gE genes of PRV within the conserved region of viral genome. The reaction process can be completed in 20 min at 39 °C. The dual real-time RPA assay performed in the single tube was capable of specific detecting and differentiating of the wild-type PRV and gE-deleted vaccine strains, without cross-reactions with other non-targeted pig viruses. The analytical sensitivity of the assay was 10 2 copies for gB and gE genes. The dual real-time RPA demonstrated a 100% diagnostic agreement with the real-time PCR on 4 PRV strains and 37 clinical samples. Through the linear regression analysis, the R 2 value of the real-time RPA and the real-time PCR for gB and gE was 0.983 and 0.992, respectively. The dual real-time RPA assay provides an alternative useful tool for rapid, simple, and reliable detection and differentiation of PRV, especially in remote and rural areas. Copyright © 2017 Elsevier Inc. All rights reserved.

Direct detection of Leishmania from clinical samples.

PubMed

Waitumbi, John N; Bast, Joshua; Nyakoe, Nancy; Magiri, Charles; Quintana, Miguel; Takhampunya, Ratree; Schuster, Anthony L; Van de Wyngaerde, Marshall T; McAvin, James C; Coleman, Russell E

2017-01-01

The ability to rapidly and accurately diagnose leishmaniasis is a military priority. Testing was conducted to evaluate diagnostic sensitivity and specificity of field-expedient Leishmania genus and visceral Leishmania specific dual-fluorogenic, hydrolysis probe (TaqMan), polymerase chain reaction assays previously established for use in vector surveillance. Blood samples of patients with confirmed visceral leishmaniasis and controls without the disease from Baringo District, Kenya, were tested. Leishmania genus assay sensitivity was 100% (14/14) and specificity was 84% (16/19). Visceral Leishmania assay sensitivity was 93% (13/14) and specificity 80% (4/5). Cutaneous leishmaniasis (CL) skin scrapes of patients from Honduras were also evaluated. Leishmania genus assay sensitivity was 100% (10/10). Visceral Leishmania assay specificity was 100% (10/10) from cutaneous leishmaniasis samples; no fluorescence above background was reported. These results show promise in a rapid, sensitive, and specific method for Leishmania direct detection from clinical samples.

Mechanical stress regulates insulin sensitivity through integrin-dependent control of insulin receptor localization.

PubMed

Kim, Jung; Bilder, David; Neufeld, Thomas P

2018-01-15

Insulin resistance, the failure to activate insulin signaling in the presence of ligand, leads to metabolic diseases, including type 2 diabetes. Physical activity and mechanical stress have been shown to protect against insulin resistance, but the molecular mechanisms remain unclear. Here, we address this relationship in the Drosophila larval fat body, an insulin-sensitive organ analogous to vertebrate adipose tissue and livers. We found that insulin signaling in Drosophila fat body cells is abolished in the absence of physical activity and mechanical stress even when excess insulin is present. Physical movement is required for insulin sensitivity in both intact larvae and fat bodies cultured ex vivo. Interestingly, the insulin receptor and other downstream components are recruited to the plasma membrane in response to mechanical stress, and this membrane localization is rapidly lost upon disruption of larval or tissue movement. Sensing of mechanical stimuli is mediated in part by integrins, whose activation is necessary and sufficient for mechanical stress-dependent insulin signaling. Insulin resistance develops naturally during the transition from the active larval stage to the immotile pupal stage, suggesting that regulation of insulin sensitivity by mechanical stress may help coordinate developmental programming with metabolism. © 2018 Kim et al.; Published by Cold Spring Harbor Laboratory Press.

A 3D Chemically Modified Graphene Hydrogel for Fast, Highly Sensitive, and Selective Gas Sensor.

PubMed

Wu, Jin; Tao, Kai; Guo, Yuanyuan; Li, Zhong; Wang, Xiaotian; Luo, Zhongzhen; Feng, Shuanglong; Du, Chunlei; Chen, Di; Miao, Jianmin; Norford, Leslie K

2017-03-01

Reduced graphene oxide (RGO) has proved to be a promising candidate in high-performance gas sensing in ambient conditions. However, trace detection of different kinds of gases with simultaneously high sensitivity and selectivity is challenging. Here, a chemiresistor-type sensor based on 3D sulfonated RGO hydrogel (S-RGOH) is reported, which can detect a variety of important gases with high sensitivity, boosted selectivity, fast response, and good reversibility. The NaHSO 3 functionalized RGOH displays remarkable 118.6 and 58.9 times higher responses to NO 2 and NH 3 , respectively, compared with its unmodified RGOH counterpart. In addition, the S-RGOH sensor is highly responsive to volatile organic compounds. More importantly, the characteristic patterns on the linearly fitted response-temperature curves are employed to distinguish various gases for the first time. The temperature of the sensor is elevated rapidly by an imbedded microheater with little power consumption. The 3D S-RGOH is characterized and the sensing mechanisms are proposed. This work gains new insights into boosting the sensitivity of detecting various gases by combining chemical modification and 3D structural engineering of RGO, and improving the selectivity of gas sensing by employing temperature dependent response characteristics of RGO for different gases.

Rapid Typing of Transmissible Spongiform Encephalopathy Strains with Differential ELISA

PubMed Central

Simon, Stéphanie; Nugier, Jérôme; Morel, Nathalie; Boutal, Hervé; Créminon, Christophe; Benestad, Sylvie L.; Andréoletti, Olivier; Lantier, Frédéric; Bilheude, Jean-Marc; Feyssaguet, Muriel; Biacabe, Anne-Gaëlle; Baron, Thierry

2008-01-01

The bovine spongiform encephalopathy (BSE) agent has been transmitted to humans, leading to variant Creutzfeldt-Jakob disease. Sheep and goats can be experimentally infected by BSE and have been potentially exposed to natural BSE; however, whether BSE can be transmitted to small ruminants is not known. Based on the particular biochemical properties of the abnormal prion protein (PrPsc) associated with BSE, and particularly the increased degradation induced by proteinase K in the N terminal part of PrPsc, we have developed a rapid ELISA designed to distinguish BSE from other scrapie strains. This assay clearly discriminates experimental ovine BSE from other scrapie strains and was used to screen 260 transmissible spongiform encephalopathy (TSE)–infected small ruminant samples identified by the French active surveillance network (2002/2003). In this context, this test has helped to identify the first case of natural BSE in a goat and can be used to classify TSE isolates based on the proteinase K sensitivity of PrPsc. PMID:18394279

Trace water sensor

NASA Technical Reports Server (NTRS)

Stephens, James B. (Inventor); Yang, Mary M. (Inventor); Laue, Eric G. (Inventor)

1985-01-01

A solid electrolytic type hygrometer is described, which operates with high reliability while providing rapid and sensitive response. A gold foil electrode (16) is wrapped about a hollow glass cylinder (18), a sheet (12) of hygroscopic-electrolytic material is wrapped about the foil, and a wire (14) is wound around the outside of the electrolytic sheet. Moisture passing between wire turns can be absorbed by the electrolytic material (12), and then dissociated by current passed by the electrodes (14, 16) through the electrolytic material. The cylinder has a slit (20) extending along its length, to allow resilient expansion to press the sheet of electrolytic material firmly against the electrodes. The wire turns lie against one another to cause rapid dissociation of moisture throughout the electrolytic material. Additional guard wires (42,44, FIG. 2) lie at opposite ends of the electrolytic sheet, and currents pass through them to avoid moisture buildup at the ends of the main wire coil. The electrical current through the sheet or membrane is proportional to the partial pressure of the water-vapor.

Development of a leak location system for use on underground electric power transmission cable

NASA Astrophysics Data System (ADS)

Williams, J. A.

1982-10-01

This report describes a study to evaluate methods for locating leaks of dielectric fluid from buried high voltage cable systems. Two primary types of leak location systems were investigated: (1) systems that will rapidly isolate the leak within a manhole section, typically 1000 m long on a feeder that might be 30 km long; and (2) systems that will then pinpoint the location of the leak. Rapid leak isolation was accomplished by developing an enhanced conductivity oil probe which allows the injection of a small quantity of conductive oil and which indicates the path of the oil as it drifts downstream in the direction of the leak. Two methods for pinpointing the leak were proven. The more successful method was the use of trained leak location dogs which were found to have far better sensitivity than instruments and which could detect cable oil alone without the need for additives. A tracer gas injection and detection scheme was developed for use in areas where the dogs may be unsuitable.

Rapid targeted mutational analysis of human tumours: a clinical platform to guide personalized cancer medicine

PubMed Central

Dias-Santagata, Dora; Akhavanfard, Sara; David, Serena S; Vernovsky, Kathy; Kuhlmann, Georgiana; Boisvert, Susan L; Stubbs, Hannah; McDermott, Ultan; Settleman, Jeffrey; Kwak, Eunice L; Clark, Jeffrey W; Isakoff, Steven J; Sequist, Lecia V; Engelman, Jeffrey A; Lynch, Thomas J; Haber, Daniel A; Louis, David N; Ellisen, Leif W; Borger, Darrell R; Iafrate, A John

2010-01-01

Targeted cancer therapy requires the rapid and accurate identification of genetic abnormalities predictive of therapeutic response. We sought to develop a high-throughput genotyping platform that would allow prospective patient selection to the best available therapies, and that could readily and inexpensively be adopted by most clinical laboratories. We developed a highly sensitive multiplexed clinical assay that performs very well with nucleic acid derived from formalin fixation and paraffin embedding (FFPE) tissue, and tests for 120 previously described mutations in 13 cancer genes. Genetic profiling of 250 primary tumours was consistent with the documented oncogene mutational spectrum and identified rare events in some cancer types. The assay is currently being used for clinical testing of tumour samples and contributing to cancer patient management. This work therefore establishes a platform for real-time targeted genotyping that can be widely adopted. We expect that efforts like this one will play an increasingly important role in cancer management. PMID:20432502

Reliability of HIV rapid diagnostic tests for self-testing compared with testing by health-care workers: a systematic review and meta-analysis.

PubMed

Figueroa, Carmen; Johnson, Cheryl; Ford, Nathan; Sands, Anita; Dalal, Shona; Meurant, Robyn; Prat, Irena; Hatzold, Karin; Urassa, Willy; Baggaley, Rachel

2018-06-01

The ability of individuals to use HIV self-tests correctly is debated. To inform the 2016 WHO recommendation on HIV self-testing, we assessed the reliability and performance of HIV rapid diagnostic tests when used by self-testers. In this systematic review and meta-analysis, we searched PubMed, PopLine, and Embase, conference abstracts, and additional grey literature between Jan 1, 1995, and April 30, 2016, for observational and experimental studies reporting on HIV self-testing performance. We excluded studies evaluating home specimen collection because patients did not interpret their own test results. We extracted data independently, using standardised extraction forms. Outcomes of interest were agreement between self-testers and health-care workers, sensitivity, and specificity. We calculated κ to establish the level of agreement and pooled κ estimates using a random-effects model, by approach (directly assisted or unassisted) and type of specimen (blood or oral fluid). We examined heterogeneity with the I 2 statistic. 25 studies met inclusion criteria (22 to 5662 participants). Quality assessment with QUADAS-2 showed studies had low risk of bias and incomplete reporting in accordance with the STARD checklist. Raw proportion of agreement ranged from 85·4% to 100%, and reported κ ranged from fair (κ 0·277, p<0·001) to almost perfect (κ 0·99, n=25). Pooled κ suggested almost perfect agreement for both types of approaches (directly assisted 0·98, 95% CI 0·96-0·99 and unassisted 0·97, 0·96-0·98; I 2 =34·5%, 0-97·8). Excluding two outliers, sensitivity and specificity was higher for blood-based rapid diagnostic tests (4/16) compared with oral fluid rapid diagnostic tests (13/16). The most common error that affected test performance was incorrect specimen collection (oral swab or finger prick). Study limitations included the use of different reference standards and no disaggregation of results by individuals taking antiretrovirals. Self-testers can reliably and accurately do HIV rapid diagnostic tests, as compared with trained health-care workers. Errors in performance might be reduced through the improvement of rapid diagnostic tests for self-testing, particularly to make sample collection easier and to simplify instructions for use. The Bill & Melinda Gates Foundation and Unitaid. © 2018. World Health Oranization. Licensee Elseviere. This is an Open Access article published under the CC BY 3.0 IGO license which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. In any use of this article, there should be no suggestion that WHO endorses any specific organisation, products or services. The use of the WHO logo is not permitted. This notice should be preserved along with the article's original URL.

Direct ultrasensitive electrical detection of prostate cancer biomarkers with CMOS-compatible n- and p-type silicon nanowire sensor arrays

NASA Astrophysics Data System (ADS)

Gao, Anran; Lu, Na; Dai, Pengfei; Fan, Chunhai; Wang, Yuelin; Li, Tie

2014-10-01

Sensitive and quantitative analysis of proteins is central to disease diagnosis, drug screening, and proteomic studies. Here, a label-free, real-time, simultaneous and ultrasensitive prostate-specific antigen (PSA) sensor was developed using CMOS-compatible silicon nanowire field effect transistors (SiNW FET). Highly responsive n- and p-type SiNW arrays were fabricated and integrated on a single chip with a complementary metal oxide semiconductor (CMOS) compatible anisotropic self-stop etching technique which eliminated the need for a hybrid method. The incorporated n- and p-type nanowires revealed complementary electrical response upon PSA binding, providing a unique means of internal control for sensing signal verification. The highly selective, simultaneous and multiplexed detection of PSA marker at attomolar concentrations, a level useful for clinical diagnosis of prostate cancer, was demonstrated. The detection ability was corroborated to be effective by comparing the detection results at different pH values. Furthermore, the real-time measurement was also carried out in a clinically relevant sample of blood serum, indicating the practicable development of rapid, robust, high-performance, and low-cost diagnostic systems.Sensitive and quantitative analysis of proteins is central to disease diagnosis, drug screening, and proteomic studies. Here, a label-free, real-time, simultaneous and ultrasensitive prostate-specific antigen (PSA) sensor was developed using CMOS-compatible silicon nanowire field effect transistors (SiNW FET). Highly responsive n- and p-type SiNW arrays were fabricated and integrated on a single chip with a complementary metal oxide semiconductor (CMOS) compatible anisotropic self-stop etching technique which eliminated the need for a hybrid method. The incorporated n- and p-type nanowires revealed complementary electrical response upon PSA binding, providing a unique means of internal control for sensing signal verification. The highly selective, simultaneous and multiplexed detection of PSA marker at attomolar concentrations, a level useful for clinical diagnosis of prostate cancer, was demonstrated. The detection ability was corroborated to be effective by comparing the detection results at different pH values. Furthermore, the real-time measurement was also carried out in a clinically relevant sample of blood serum, indicating the practicable development of rapid, robust, high-performance, and low-cost diagnostic systems. Electronic supplementary information (ESI) available: Electrical characterization of fabricated n- and p-type nanowires, and influence of Debye screening on PSA sensing. See DOI: 10.1039/c4nr03210a

Using the Web to Collect Data on Sensitive Behaviours: A Study Looking at Mode Effects on the British National Survey of Sexual Attitudes and Lifestyles

PubMed Central

Burkill, Sarah; Copas, Andrew; Couper, Mick P.; Clifton, Soazig; Prah, Philip; Datta, Jessica; Conrad, Frederick; Wellings, Kaye; Johnson, Anne M.; Erens, Bob

2016-01-01

Background Interviewer-administered surveys are an important method of collecting population-level epidemiological data, but suffer from declining response rates and increasing costs. Web surveys offer more rapid data collection and lower costs. There are concerns, however, about data quality from web surveys. Previous research has largely focused on selection biases, and few have explored measurement differences. This paper aims to assess the extent to which mode affects the responses given by the same respondents at two points in time, providing information on potential measurement error if web surveys are used in the future. Methods 527 participants from the third British National Survey of Sexual Attitudes and Lifestyles (Natsal-3), which uses computer assisted personal interview (CAPI) and self-interview (CASI) modes, subsequently responded to identically-worded questions in a web survey. McNemar tests assessed whether within-person differences in responses were at random or indicated a mode effect, i.e. higher reporting of more sensitive responses in one mode. An analysis of pooled responses by generalized estimating equations addressed the impact of gender and question type on change. Results Only 10% of responses changed between surveys. However mode effects were found for about a third of variables, with higher reporting of sensitive responses more commonly found on the web compared with Natsal-3. Conclusions The web appears a promising mode for surveys of sensitive behaviours, most likely as part of a mixed-mode design. Our findings suggest that mode effects may vary by question type and content, and by the particular mix of modes used. Mixed-mode surveys need careful development to understand mode effects and how to account for them. PMID:26866687

[Comparison of detection sensitivity in rapid-diagnosis influenza virus kits].

PubMed

Tokuno, Osamu; Fujiwara, Miki; Nakajoh, Yoshimi; Yamanouchi, Sumika; Adachi, Masayo; Ikeda, Akiko; Kitayama, Shigeo; Takahashi, Toshio; Kase, Tetsuo; Kinoshita, Shouhiro; Kumagai, Shunichi

2009-09-01

Rapid-diagnosis kits able to detect influenza A and B virus by immunochromatography developed by different manufacturers, while useful in early diagnosis, may vary widely in detection sensitivity. We compared sensitivity results for eight virus-detection kits in current use--Quick Chaser FluA, B (Mizuho Medy), Espline Influenza A & B-N (Fujirebio), Capilia Flu A + B (Nippon Beckton Dickinson & Alfesa Pharma), Poctem Influenza A/B (Otsuka Pharma & Sysmex), BD Flu Examan (Nippon Beckton Dickinson), Quick Ex-Flu "Seiken" (Denka Seiken), Quick Vue Rapid SP Influ (DP Pharma Biomedical), and Rapid Testa FLU stick (Daiichi Pure Chemicals)--against influenza virus stocks, contained five vaccination strains (one A/H1N1, two A/H3N2, and two B) and six clinical strains (two A/H1N1, two A/H3N2, and two B). Minimum detection concentrations giving immunologically positive signals in serial dilution and RNA copies in positive dilution in real-time reverse transcriptase-polymerase chain reaction (RT-PCR) were assayed for all kits and virus stock combinations. RNA log10 copy numbers/mL in dilutions within detection limits yielded 5.68-7.02, 6.37-7,17, and 6.5-8.13 for A/H1N1, A/H3N2, and B. Statistically significant differences in sensitivity were observed between some kit combinations. Detection sensitivity tended to be relatively higher for influenza A than B virus. This is assumed due to different principles in kit methods, such as monoclonal antibodies, specimen-extraction conditions, and other unknown factors.

Quantum Dot-Fullerene Based Molecular Beacon Nanosensors for Rapid, Highly Sensitive Nucleic Acid Detection.

PubMed

Liu, Ye; Kannegulla, Akash; Wu, Bo; Cheng, Li-Jing

2018-05-15

Spherical fullerene (C 60 ) can quench the fluorescence of a quantum dot (QD) through energy transfer and charge transfer processes, with the quenching efficiency regulated by the number of proximate C 60 on each QD. With the quenching property and its small size compared with other nanoparticle-based quenchers, it is advantageous to group a QD reporter and multiple C 60 -labeled oligonucleotide probes to construct a molecular beacon (MB) probe for sensitive, robust nucleic acid detection. We demonstrated a rapid, high-sensitivity DNA detection method using the nanosensors composed of QD-C 60 based MBs carried by magnetic nanoparticles (MNPs). The assay was accelerated by first dispersing the nanosensors in analytes for highly efficient DNA capture resulting from short-distance 3-dimensional diffusion of targets to the sensor surface and then concentrating the nanosensors to a substrate by magnetic force to amplify the fluorescence signal for target quantification. The enhanced mass transport enabled a rapid detection (< 10 min) with a small sample volume (1-10 µl). The high signal-to-noise ratio produced by the QD-C 60 pairs and magnetic concentration yielded a detection limit of 100 fM (~106 target DNA copies for a 10 µl analyte). The rapid, sensitive, label-free detection method will benefit the applications in point-of-care molecular diagnostic technologies.

Enhanced Sensitivity to Rapid Input Fluctuations by Nonlinear Threshold Dynamics in Neocortical Pyramidal Neurons.

PubMed

Mensi, Skander; Hagens, Olivier; Gerstner, Wulfram; Pozzorini, Christian

2016-02-01

The way in which single neurons transform input into output spike trains has fundamental consequences for network coding. Theories and modeling studies based on standard Integrate-and-Fire models implicitly assume that, in response to increasingly strong inputs, neurons modify their coding strategy by progressively reducing their selective sensitivity to rapid input fluctuations. Combining mathematical modeling with in vitro experiments, we demonstrate that, in L5 pyramidal neurons, the firing threshold dynamics adaptively adjust the effective timescale of somatic integration in order to preserve sensitivity to rapid signals over a broad range of input statistics. For that, a new Generalized Integrate-and-Fire model featuring nonlinear firing threshold dynamics and conductance-based adaptation is introduced that outperforms state-of-the-art neuron models in predicting the spiking activity of neurons responding to a variety of in vivo-like fluctuating currents. Our model allows for efficient parameter extraction and can be analytically mapped to a Generalized Linear Model in which both the input filter--describing somatic integration--and the spike-history filter--accounting for spike-frequency adaptation--dynamically adapt to the input statistics, as experimentally observed. Overall, our results provide new insights on the computational role of different biophysical processes known to underlie adaptive coding in single neurons and support previous theoretical findings indicating that the nonlinear dynamics of the firing threshold due to Na+-channel inactivation regulate the sensitivity to rapid input fluctuations.

A loop-mediated isothermal amplification assay for rapid and sensitive detection of bovine papular stomatitis virus.

PubMed

Kurosaki, Yohei; Okada, Sayaka; Nakamae, Sayuri; Yasuda, Jiro

2016-12-01

Bovine papular stomatitis virus (BPSV) causes pustular cutaneous disease in cattle worldwide. This paper describes the development of a specific loop-mediated isothermal amplification (LAMP) assay to detect BPSV which did not cross-react with other parapoxviruses. To assess analytical sensitivity of this LAMP assay, DNA was extracted from serially diluted BPSV from which the infectious titer was determined by a novel assay based on calf kidney epithelial cells. The LAMP assay had equivalent analytical sensitivity to quantitative PCR, and could detect as few as 86 copies of viral DNA per reaction. These results suggest that the assay is a specific and sensitive technique to rapidly diagnose bovine papular stomatitis in domestic animals. Copyright © 2016 Elsevier B.V. All rights reserved.

Microfluidics for rapid detection of isocitrate dehydrogenase 1 mutation for intraoperative application.

PubMed

Aibaidula, Abudumijiti; Zhao, Wang; Wu, Jin-Song; Chen, Hong; Shi, Zhi-Feng; Zheng, Lu-Lu; Mao, Ying; Zhou, Liang-Fu; Sui, Guo-Dong

2016-06-01

OBJECT Conventional methods for isocitrate dehydrogenase 1 (IDH1) detection, such as DNA sequencing and immunohistochemistry, are time- and labor-consuming and cannot be applied for intraoperative analysis. To develop a new approach for rapid analysis of IDH1 mutation from tiny tumor samples, this study used microfluidics as a method for IDH1 mutation detection. METHODS Forty-seven glioma tumor samples were used; IDH1 mutation status was investigated by immunohistochemistry and DNA sequencing. The microfluidic device was fabricated from polydimethylsiloxane following standard soft lithography. The immunoanalysis was conducted in the microfluidic chip. Fluorescence images of the on-chip microcolumn taken by the charge-coupled device camera were collected as the analytical results readout. Fluorescence signals were analyzed by NIS-Elements software to gather detailed information about the IDH1 concentration in the tissue samples. RESULTS DNA sequencing identified IDH1 R132H mutation in 33 of 47 tumor samples. The fluorescence signal for IDH1-mutant samples was 5.49 ± 1.87 compared with 3.90 ± 1.33 for wild type (p = 0.005). Thus, microfluidics was capable of distinguishing IDH1-mutant tumor samples from wild-type samples. When the cutoff value was 4.11, the sensitivity of microfluidics was 87.9% and the specificity was 64.3%. CONCLUSIONS This new approach was capable of analyzing IDH1 mutation status of tiny tissue samples within 30 minutes using intraoperative microsampling. This approach might also be applied for rapid pathological diagnosis of diffuse gliomas, thus guiding personalized resection.

One-Pot Reverse Transcriptional Loop-Mediated Isothermal Amplification (RT-LAMP) for Detecting MERS-CoV

PubMed Central

Lee, Se Hee; Baek, Yun Hee; Kim, Yang-Hoon; Choi, Young-Ki; Song, Min-Suk; Ahn, Ji-Young

2017-01-01

Due to the limitation of rapid development of specific antiviral drug or vaccine for novel emerging viruses, an accurate and rapid diagnosis is a key to manage the virus spread. We developed an efficient and rapid method with high specificity for the Middle East Respiratory Syndrome coronavirus (MERS-CoV), based on one-pot reverse transcription loop-mediated isothermal amplification (one-pot RT-LAMP). A set of six LAMP primers [F3, B3, FIP, BIP, LF (Loop-F), and LB (Loop-B)] were designed using the sequence of nucleocapsid (N) gene with optimized RT-LAMP enzyme conditions: 100 U M-MLV RTase and 4 U Bst polymerase, implying that the reaction was able to detect four infectious viral genome copies of MERS-CoV within a 60 min reaction time period. Significantly, EvaGreen dye has better signal read-out properties in one-pot RT-LAMP reaction and is more compatible with DNA polymerase than SYBR green I. Isothermally amplified specific N genes were further evaluated using field-deployable microchamber devices, leading to the specific identification of as few as 0.4 infectious viral genome copies, with no cross-reaction to the other acute respiratory disease viruses, including influenza type A (H1N1 and H3N2), type B, human coronavirus 229E, and human metapneumovirus. This sensitive, specific and feasible method provides a large-scale technical support in emergencies, and is also applied as a sample-to-detection module in Point of Care Testing devices. PMID:28119682

Generation of E. coli-derived virus-like particles of porcine circovirus type 2 and their use in an indirect IgG enzyme-linked immunosorbent assay.

PubMed

Zhang, Yan; Wang, Zhanfeng; Zhan, Yang; Gong, Qian; Yu, Wanting; Deng, Zhibang; Wang, Aibing; Yang, Yi; Wang, Naidong

2016-06-01

Porcine circovirus type 2 (PCV2) causes increased mortality and poor growth or weight loss in apparently healthy swine. Therefore, methods to detect PCV2-specific antibodies in swine serum are important for prevention, diagnosis, and control of PCV2-associated diseases (PCVAD). In this study, PCV2 virus-like particles (VLPs) were used to develop a rapid, simple and economical indirect enzyme-linked immunosorbent assay to detect (with high sensitivity) PCV2-specific antibodies in swine serum. The PCV2 capsid protein (Cap) was overexpressed in E. coli after optimizing the cap gene. Subsequently, the soluble Cap was rapidly purified in one step by automated fast protein liquid chromatography (FPLC). The purified PCV2 Cap was shown by transmission electron microscopy and gel filtration chromatography to be capable of self-assembling into VLPs in vitro. Using the purified VLPs as antigens, optimal operating conditions for the VLP ELISA were determined. The concentration of PCV2 VLPs was 1 µg/ml per well, and the dilution factors for swine serum and horseradish peroxidase (HRP)-labeled goat anti-pig antibody were 1:150 and 1:4000, respectively. Out of 241 serum samples tested with this assay, 83.4 % were found to be positive. Importantly, the VLP ELISA had a total coincidence rate of 97.4 % (74/76) compared to an Ingezim PCV2 ELISA IgG assay. In summary, this rapid, inexpensive VLP ELISA has the potential to greatly facilitate large-scale investigations of PCV2-associated serotypes.

Development of a method for urine bikunin/urinary trypsin inhibitor (UTI) quantitation and structural characterization: Application to type 1 and type 2 diabetes.

PubMed

Lepedda, Antonio Junior; Nieddu, Gabriele; Rocchiccioli, Silvia; Fresu, Pietro; De Muro, Pierina; Formato, Marilena

2013-12-01

Bikunin is a plasma proteinase inhibitor often associated with inflammatory conditions. It has a half-life of few minutes and it is rapidly excreted into urine as urinary trypsin inhibitor (UTI). UTI levels are usually low in healthy individuals but they can increase up to tenfold in both acute and chronic inflammatory diseases. This article describes a sensitive method for both direct UTI quantitation and structural characterization. UTI purification was performed by anion exchange micro-chromatography followed by SDS-PAGE. A calibration curve for protein quantitation was set up by using a purified UTI fraction. UTI identification and structural characterization was performed by Nano-LC-MS/MS analysis. The method was applied on urine samples from 9 patients with type 1 diabetes, 11 patients with type 2 diabetes, and 28 healthy controls, matched for age and sex with patients, evidencing higher UTI levels in both groups of patients with respect to controls (p < 0.001 and p = 0.001, respectively). Spearman's correlation tests highlighted no association between UTI levels and age in each group tested. Owing to the elevated sensitivity and specificity, the described method allows UTI quantitation from very low quantities of specimen. Furthermore, as UTI concentration is normalized for creatinine level, the analysis could be also performed on randomly collected urine samples. Finally, MS/MS analysis prospects the possibility of characterizing PTM sites potentially able to affect UTI localization, function, and pathophysiological activity. Preliminary results suggest that UTI levels could represent a useful marker of chronic inflammatory condition in type 1 and 2 diabetes. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Multicenter Clinical Evaluation of the Novel Alere i Strep A Isothermal Nucleic Acid Amplification Test.

PubMed

Cohen, Daniel M; Russo, Michael E; Jaggi, Preeti; Kline, Jennifer; Gluckman, William; Parekh, Amisha

2015-07-01

Rapid detection of group A beta-hemolytic streptococcus (GAS) is used routinely to help diagnose and treat pharyngitis. However, available rapid antigen detection tests for GAS have relatively low sensitivity, and backup testing is recommended in children. Newer assays are more sensitive yet require excessive time for practical point-of-care use as well as laboratory personnel. The Alere i strep A test is an isothermal nucleic acid amplification test designed to offer highly sensitive results at the point of care within 8 min when performed by nonlaboratory personnel. The performance of the Alere i strep A test was evaluated in a multicenter prospective trial in a Clinical Laboratory Improvement Amendments (CLIA)-waived setting in comparison to bacterial culture in 481 children and adults. Compared to culture, the Aleri i strep A test had 96.0% sensitivity and 94.6% specificity. Discrepant results were adjudicated by PCR and found the Alere i strep A test to have 98.7% sensitivity and 98.5% specificity. Overall, the Alere i strep A test could provide a one-step, rapid, point-of-care testing method for GAS pharyngitis and obviate backup testing on negative results. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

Google Glass Glare: disability glare produced by a head-mounted visual display.

PubMed

Longley, Chris; Whitaker, David

2016-03-01

Head mounted displays are a type of wearable technology - a market that is projected to expand rapidly over the coming years. Probably the most well known example is the device Google Glass (or 'Glass'). Here we investigate the extent to which the device display can interfere with normal visual function by producing monocular disability glare. Contrast sensitivity was measured in two normally sighted participants, 32 and 52 years of age. Data were recorded for the right eye, the left eye and then again in a binocular condition. Measurements were taken both with and without the Glass in place, across a range of stimulus luminance levels using a two-alternative forced-choice methodology. The device produced a significant reduction in contrast sensitivity in the right eye (>0.5 log units). The level of disability glare increased as stimulus luminance was reduced in a manner consistent with intraocular light scatter, resulting in a veiling retinal illuminance. Sensitivity in the left eye was unaffected. A significant reduction in binocular contrast sensitivity occurred at lower luminance levels due to a loss of binocular summation, although binocular sensitivity was not found to fall below the sensitivity of the better monocular level (binocular inhibition). Head mounted displays such as Google Glass have the potential to cause significant disability glare in the eye exposed to the visual display, particularly under conditions of low luminance. They can also cause a more modest binocular reduction in sensitivity by eliminating the benefits of binocular summation. © 2015 The Authors Ophthalmic & Physiological Optics © 2015 The College of Optometrists.

Beware the black box: investigating the sensitivity of FEA simulations to modelling factors in comparative biomechanics.

PubMed

Walmsley, Christopher W; McCurry, Matthew R; Clausen, Phillip D; McHenry, Colin R

2013-01-01

Finite element analysis (FEA) is a computational technique of growing popularity in the field of comparative biomechanics, and is an easily accessible platform for form-function analyses of biological structures. However, its rapid evolution in recent years from a novel approach to common practice demands some scrutiny in regards to the validity of results and the appropriateness of assumptions inherent in setting up simulations. Both validation and sensitivity analyses remain unexplored in many comparative analyses, and assumptions considered to be 'reasonable' are often assumed to have little influence on the results and their interpretation. HERE WE REPORT AN EXTENSIVE SENSITIVITY ANALYSIS WHERE HIGH RESOLUTION FINITE ELEMENT (FE) MODELS OF MANDIBLES FROM SEVEN SPECIES OF CROCODILE WERE ANALYSED UNDER LOADS TYPICAL FOR COMPARATIVE ANALYSIS: biting, shaking, and twisting. Simulations explored the effect on both the absolute response and the interspecies pattern of results to variations in commonly used input parameters. Our sensitivity analysis focuses on assumptions relating to the selection of material properties (heterogeneous or homogeneous), scaling (standardising volume, surface area, or length), tooth position (front, mid, or back tooth engagement), and linear load case (type of loading for each feeding type). Our findings show that in a comparative context, FE models are far less sensitive to the selection of material property values and scaling to either volume or surface area than they are to those assumptions relating to the functional aspects of the simulation, such as tooth position and linear load case. Results show a complex interaction between simulation assumptions, depending on the combination of assumptions and the overall shape of each specimen. Keeping assumptions consistent between models in an analysis does not ensure that results can be generalised beyond the specific set of assumptions used. Logically, different comparative datasets would also be sensitive to identical simulation assumptions; hence, modelling assumptions should undergo rigorous selection. The accuracy of input data is paramount, and simulations should focus on taking biological context into account. Ideally, validation of simulations should be addressed; however, where validation is impossible or unfeasible, sensitivity analyses should be performed to identify which assumptions have the greatest influence upon the results.

Beware the black box: investigating the sensitivity of FEA simulations to modelling factors in comparative biomechanics

PubMed Central

McCurry, Matthew R.; Clausen, Phillip D.; McHenry, Colin R.

2013-01-01

Finite element analysis (FEA) is a computational technique of growing popularity in the field of comparative biomechanics, and is an easily accessible platform for form-function analyses of biological structures. However, its rapid evolution in recent years from a novel approach to common practice demands some scrutiny in regards to the validity of results and the appropriateness of assumptions inherent in setting up simulations. Both validation and sensitivity analyses remain unexplored in many comparative analyses, and assumptions considered to be ‘reasonable’ are often assumed to have little influence on the results and their interpretation. Here we report an extensive sensitivity analysis where high resolution finite element (FE) models of mandibles from seven species of crocodile were analysed under loads typical for comparative analysis: biting, shaking, and twisting. Simulations explored the effect on both the absolute response and the interspecies pattern of results to variations in commonly used input parameters. Our sensitivity analysis focuses on assumptions relating to the selection of material properties (heterogeneous or homogeneous), scaling (standardising volume, surface area, or length), tooth position (front, mid, or back tooth engagement), and linear load case (type of loading for each feeding type). Our findings show that in a comparative context, FE models are far less sensitive to the selection of material property values and scaling to either volume or surface area than they are to those assumptions relating to the functional aspects of the simulation, such as tooth position and linear load case. Results show a complex interaction between simulation assumptions, depending on the combination of assumptions and the overall shape of each specimen. Keeping assumptions consistent between models in an analysis does not ensure that results can be generalised beyond the specific set of assumptions used. Logically, different comparative datasets would also be sensitive to identical simulation assumptions; hence, modelling assumptions should undergo rigorous selection. The accuracy of input data is paramount, and simulations should focus on taking biological context into account. Ideally, validation of simulations should be addressed; however, where validation is impossible or unfeasible, sensitivity analyses should be performed to identify which assumptions have the greatest influence upon the results. PMID:24255817

Development of a selective and sensitive flotation method for determination of trace amounts of cobalt, nickel, copper and iron in environmental samples.

PubMed

Karimi, H; Ghaedi, M; Shokrollahi, A; Rajabi, H R; Soylak, M; Karami, B

2008-02-28

A simple, selective and rapid flotation method for the separation-preconcentration of trace amounts of cobalt, nickel, iron and copper ions using phenyl 2-pyridyl ketone oxime (PPKO) has been developed prior to their flame atomic absorption spectrometric determinations. The influence of pH, amount of PPKO as collector, type and amount of eluting agent, type and amount of surfactant as floating agent and ionic strength was evaluated on the recoveries of analytes. The influences of the concomitant ions on the recoveries of the analyte ions were also examined. The enrichment factor was 93. The detection limits based on 3 sigma for Cu, Ni, Co and Fe were 0.7, 0.7, 0.8, and 0.7 ng mL(-1), respectively. The method has been successfully applied for determination of trace amounts of ions in various real samples.

REBASE--a database for DNA restriction and modification: enzymes, genes and genomes.

PubMed

Roberts, Richard J; Vincze, Tamas; Posfai, Janos; Macelis, Dana

2015-01-01

REBASE is a comprehensive and fully curated database of information about the components of restriction-modification (RM) systems. It contains fully referenced information about recognition and cleavage sites for both restriction enzymes and methyltransferases as well as commercial availability, methylation sensitivity, crystal and sequence data. All genomes that are completely sequenced are analyzed for RM system components, and with the advent of PacBio sequencing, the recognition sequences of DNA methyltransferases (MTases) are appearing rapidly. Thus, Type I and Type III systems can now be characterized in terms of recognition specificity merely by DNA sequencing. The contents of REBASE may be browsed from the web http://rebase.neb.com and selected compilations can be downloaded by FTP (ftp.neb.com). Monthly updates are also available via email. © The Author(s) 2014. Published by Oxford University Press on behalf of Nucleic Acids Research.

Screening for trace explosives by AccuTOF™-DART®: an in-depth validation study.

PubMed

Sisco, Edward; Dake, Jeffrey; Bridge, Candice

2013-10-10

Ambient ionization mass spectrometry is finding increasing utility as a rapid analysis technique in a number of fields. In forensic science specifically, analysis of many types of samples, including drugs, explosives, inks, bank dye, and lotions, has been shown to be possible using these techniques [1]. This paper focuses on one type of ambient ionization mass spectrometry, Direct Analysis in Real Time Mass Spectrometry (DART-MS or DART), and its viability as a screening tool for trace explosives analysis. In order to assess viability, a validation study was completed which focused on the analysis of trace amounts of nitro and peroxide based explosives. Topics which were studied, and are discussed, include method optimization, reproducibility, sensitivity, development of a search library, discrimination of mixtures, and blind sampling. Advantages and disadvantages of this technique over other similar screening techniques are also discussed. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

The human T-cell leukemia virus type 1 p13II protein: effects on mitochondrial function and cell growth

PubMed Central

D’Agostino, DM; Silic-Benussi, M; Hiraragi, H; Lairmore, MD; Ciminale, V

2011-01-01

p13II of human T-cell leukemia virus type 1 (HTLV-1) is an 87-amino-acid protein that is targeted to the inner mitochondrial membrane. p13II alters mitochondrial membrane permeability, producing a rapid, membrane potential-dependent influx of K+. These changes result in increased mitochondrial matrix volume and fragmentation and may lead to depolarization and alterations in mitochondrial Ca2+ uptake/retention capacity. At the cellular level, p13II has been found to interfere with cell proliferation and transformation and to promote apoptosis induced by ceramide and Fas ligand. Assays carried out in T cells (the major targets of HTLV-1 infection in vivo) demonstrate that p13II-mediated sensitization to Fas ligand-induced apoptosis can be blocked by an inhibitor of Ras farnesylation, thus implicating Ras signaling as a downstream target of p13II function. PMID:15761473

Rapid Detection of Cell-Free Mycobacterium tuberculosis DNA in Tuberculous Pleural Effusion.

PubMed

Che, Nanying; Yang, Xinting; Liu, Zichen; Li, Kun; Chen, Xiaoyou

2017-05-01

Tuberculous pleurisy is one of the most common types of extrapulmonary tuberculosis, but its diagnosis remains difficult. In this study, we report for the first time on the detection of cell-free Mycobacterium tuberculosis DNA in pleural effusion and an evaluation of a newly developed molecular assay for the detection of cell-free Mycobacterium tuberculosis DNA. A total of 78 patients with pleural effusion, 60 patients with tuberculous pleurisy, and 18 patients with alternative diseases were included in this study. Mycobacterial culture, the Xpert MTB/RIF assay, the adenosine deaminase assay, the T-SPOT.TB assay, and the cell-free Mycobacterium tuberculosis DNA assay were performed on all the pleural effusion samples. The cell-free Mycobacterium tuberculosis DNA assay and adenosine deaminase assay showed significantly higher sensitivities of 75.0% and 68.3%, respectively, than mycobacterial culture and the Xpert MTB/RIF assay, which had sensitivities of 26.7% and 20.0%, respectively ( P < 0.01). All four of these tests showed good specificities: 88.9% for the adenosine deaminase assay and 100% for the remaining three assays. The T-SPOT.TB assay with pleural effusion showed the highest sensitivity of 95.0% but the lowest specificity of 38.9%. The cell-free Mycobacterium tuberculosis DNA assay detected as few as 1.25 copies of IS 6110 per ml of pleural effusion and showed good accordance of the results between repeated tests ( r = 0.978, P = 2.84 × 10 -10 ). These data suggest that the cell-free Mycobacterium tuberculosis DNA assay is a rapid and accurate molecular test which provides direct evidence of Mycobacterium tuberculosis etiology. Copyright © 2017 American Society for Microbiology.

Rapid and Parallel Adaptive Evolution of the Visual System of Neotropical Midas Cichlid Fishes.

PubMed

Torres-Dowdall, Julián; Pierotti, Michele E R; Härer, Andreas; Karagic, Nidal; Woltering, Joost M; Henning, Frederico; Elmer, Kathryn R; Meyer, Axel

2017-10-01

Midas cichlid fish are a Central American species flock containing 13 described species that has been dated to only a few thousand years old, a historical timescale infrequently associated with speciation. Their radiation involved the colonization of several clear water crater lakes from two turbid great lakes. Therefore, Midas cichlids have been subjected to widely varying photic conditions during their radiation. Being a primary signal relay for information from the environment to the organism, the visual system is under continuing selective pressure and a prime organ system for accumulating adaptive changes during speciation, particularly in the case of dramatic shifts in photic conditions. Here, we characterize the full visual system of Midas cichlids at organismal and genetic levels, to determine what types of adaptive changes evolved within the short time span of their radiation. We show that Midas cichlids have a diverse visual system with unexpectedly high intra- and interspecific variation in color vision sensitivity and lens transmittance. Midas cichlid populations in the clear crater lakes have convergently evolved visual sensitivities shifted toward shorter wavelengths compared with the ancestral populations from the turbid great lakes. This divergence in sensitivity is driven by changes in chromophore usage, differential opsin expression, opsin coexpression, and to a lesser degree by opsin coding sequence variation. The visual system of Midas cichlids has the evolutionary capacity to rapidly integrate multiple adaptations to changing light environments. Our data may indicate that, in early stages of divergence, changes in opsin regulation could precede changes in opsin coding sequence evolution. © The Author 2017. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Rapid and sensitive detection of Feline immunodeficiency virus using an insulated isothermal PCR-based assay with a point-of-need PCR detection platform.

PubMed

Wilkes, Rebecca Penrose; Kania, Stephen A; Tsai, Yun-Long; Lee, Pei-Yu Alison; Chang, Hsiu-Hui; Ma, Li-Juan; Chang, Hsiao-Fen Grace; Wang, Hwa-Tang Thomas

2015-07-01

Feline immunodeficiency virus (FIV) is an important infectious agent of cats. Clinical syndromes resulting from FIV infection include immunodeficiency, opportunistic infections, and neoplasia. In our study, a 5' long terminal repeat/gag region-based reverse transcription insulated isothermal polymerase chain reaction (RT-iiPCR) was developed to amplify all known FIV strains to facilitate point-of-need FIV diagnosis. The RT-iiPCR method was applied in a point-of-need PCR detection platform--a field-deployable device capable of generating automatically interpreted RT-iiPCR results from nucleic acids within 1 hr. Limit of detection 95% of FIV RT-iiPCR was calculated to be 95 copies standard in vitro transcription RNA per reaction. Endpoint dilution studies with serial dilutions of an ATCC FIV type strain showed that the sensitivity of lyophilized FIV RT-iiPCR reagent was comparable to that of a reference nested PCR. The established reaction did not amplify any nontargeted feline pathogens, including Felid herpesvirus 1, feline coronavirus, Feline calicivirus, Feline leukemia virus, Mycoplasma haemofelis, and Chlamydophila felis. Based on analysis of 76 clinical samples (including blood and bone marrow) with the FIV RT-iiPCR, test sensitivity was 97.78% (44/45), specificity was 100.00% (31/31), and agreement was 98.65% (75/76), determined against a reference nested-PCR assay. A kappa value of 0.97 indicated excellent correlation between these 2 methods. The lyophilized FIV RT-iiPCR reagent, deployed on a user-friendly portable device, has potential utility for rapid and easy point-of-need detection of FIV in cats. © 2015 The Author(s).

Rapid Detection of Cell-Free Mycobacterium tuberculosis DNA in Tuberculous Pleural Effusion

PubMed Central

Yang, Xinting; Liu, Zichen; Li, Kun

2017-01-01

ABSTRACT Tuberculous pleurisy is one of the most common types of extrapulmonary tuberculosis, but its diagnosis remains difficult. In this study, we report for the first time on the detection of cell-free Mycobacterium tuberculosis DNA in pleural effusion and an evaluation of a newly developed molecular assay for the detection of cell-free Mycobacterium tuberculosis DNA. A total of 78 patients with pleural effusion, 60 patients with tuberculous pleurisy, and 18 patients with alternative diseases were included in this study. Mycobacterial culture, the Xpert MTB/RIF assay, the adenosine deaminase assay, the T-SPOT.TB assay, and the cell-free Mycobacterium tuberculosis DNA assay were performed on all the pleural effusion samples. The cell-free Mycobacterium tuberculosis DNA assay and adenosine deaminase assay showed significantly higher sensitivities of 75.0% and 68.3%, respectively, than mycobacterial culture and the Xpert MTB/RIF assay, which had sensitivities of 26.7% and 20.0%, respectively (P < 0.01). All four of these tests showed good specificities: 88.9% for the adenosine deaminase assay and 100% for the remaining three assays. The T-SPOT.TB assay with pleural effusion showed the highest sensitivity of 95.0% but the lowest specificity of 38.9%. The cell-free Mycobacterium tuberculosis DNA assay detected as few as 1.25 copies of IS6110 per ml of pleural effusion and showed good accordance of the results between repeated tests (r = 0.978, P = 2.84 × 10−10). These data suggest that the cell-free Mycobacterium tuberculosis DNA assay is a rapid and accurate molecular test which provides direct evidence of Mycobacterium tuberculosis etiology. PMID:28275073

Insulin-sensitive phospholipid signaling systems and glucose transport. Update II.

PubMed

Farese, R V

2001-04-01

Insulin provokes rapid changes in phospholipid metabolism and thereby generates biologically active lipids that serve as intracellular signaling factors that regulate glucose transport and glycogen synthesis. These changes include: (i) activation of phosphatidylinositol 3-kinase (PI3K) and production of PIP3; (ii) PIP3-dependent activation of atypical protein kinase Cs (PKCs); (iii) PIP3-dependent activation of PKB; (iv) PI3K-dependent activation of phospholipase D and hydrolysis of phosphatidylcholine with subsequent increases in phosphatidic acid (PA) and diacylglycerol (DAG); (v) PI3K-independent activation of glycerol-3-phosphate acylytansferase and increases in de novo synthesis of PA and DAG; and (vi) activation of DAG-sensitive PKCs. Recent findings suggest that atypical PKCs and PKB serve as important positive regulators of insulin-stimulated glucose metabolism, whereas mechanisms that result in the activation of DAG-sensitive PKCs serve mainly as negative regulators of insulin signaling through PI3K. Atypical PKCs and PKB are rapidly activated by insulin in adipocytes, liver, skeletal muscles, and other cell types by a mechanism requiring PI3K and its downstream effector, 3-phosphoinositide-dependent protein kinase-1 (PDK-1), which, in conjunction with PIP3, phosphorylates critical threonine residues in the activation loops of atypical PKCs and PKB. PIP3 also promotes increases in autophosphorylation and allosteric activation of atypical PKCs. Atypical PKCs and perhaps PKB appear to be required for insulin-induced translocation of the GLUT 4 glucose transporter to the plasma membrane and subsequent glucose transport. PKB also appears to be the major regulator of glycogen synthase. Together, atypical PKCs and PKB serve as a potent, integrated PI3K/PDK-1-directed signaling system that is used by insulin to regulate glucose metabolism.

Real-time PCR assays for detection of Brucella spp. and the identification of genotype ST27 in bottlenose dolphins (Tursiops truncatus).

PubMed

Wu, Qingzhong; McFee, Wayne E; Goldstein, Tracey; Tiller, Rebekah V; Schwacke, Lori

2014-05-01

Rapid detection of Brucella spp. in marine mammals is challenging. Microbiologic culture is used for definitive diagnosis of brucellosis, but is time consuming, has low sensitivity and can be hazardous to laboratory personnel. Serological methods can aid in diagnosis, but may not differentiate prior exposure versus current active infection and may cross-react with unrelated Gram-negative bacteria. This study reports a real-time PCR assay for the detection of Brucella spp. and application to screen clinical samples from bottlenose dolphins stranded along the coast of South Carolina, USA. The assay was found to be 100% sensitive for the Brucella strains tested, and the limit of detection was 0.27fg of genomic DNA from Brucella ceti B1/94 per PCR volume. No amplification was detected for the non-Brucella pathogens tested. Brucella DNA was detected in 31% (55/178) of clinical samples tested. These studies indicate that the real-time PCR assay is highly sensitive and specific for the detection of Brucella spp. in bottlenose dolphins. We also developed a second real-time PCR assay for rapid identification of Brucella ST27, a genotype that is associated with human zoonotic infection. Positive results were obtained for Brucella strains which had been identified as ST27 by multilocus sequence typing. No amplification was found for other Brucella strains included in this study. ST27 was identified in 33% (18/54) of Brucella spp. DNA-positive clinical samples. To our knowledge, this is the first report on the use of a real-time PCR assay for identification of Brucella genotype ST27 in marine mammals. Copyright © 2014 Elsevier B.V. All rights reserved.

A novel sandwich enzyme-linked immunosorbent assay with covalently bound monoclonal antibody and gold probe for sensitive and rapid detection of bovine β-lactoglobulin.

PubMed

He, Shengfa; Li, Xin; Wu, Yong; Wu, Shandong; Wu, Zhihua; Yang, Anshu; Tong, Ping; Yuan, Juanli; Gao, Jinyan; Chen, Hongbing

2018-06-01

Bovine milk is a recognized allergenic food source with β-lactoglobulin (BLG) as its major allergen. Reliable detection of BLG epitopes can, therefore, be a useful marker for the presence of milk in processed food products, and for potential allergenicity. At the present, enzyme-linked immunosorbent assays (ELISA) for the detection of BLG are time-consuming and generally not specific to BLG IgE epitopes. In this study, the 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide-activated anti-BLG IgE epitope monoclonal antibody (mAb 1G9) was covalently bound onto the KOH-treated microtiter plate surface. Using this mAb-bound plate in sandwich combination with biotinylated anti-BLG polyclonal antibody-labeled gold nanoparticles, a linear dynamic range between 31.25 and 64 × 10 3  ng mL -1 with a limit of detection for BLG of 0.49 ng mL -1 was obtained, which is 32 times wider and 16 times more sensitive than conventional sandwich ELISA (sELISA). Total recovery of BLG in spiked food samples was found, without matrix effects. Also in partially hydrolyzed infant formulas, the allergenic BLG residues were detected quantitatively. Compared with conventional and commercial BLG detection sELISAs, our sELISA is reliable, highly BLG epitope-specific, user-friendly, and time-saving and allows accurate detection of potentially allergenic residues in different types of processed foods. This improved sELISA protocol can be easily extended to detect other well-identified and characterized food allergens. Graphical abstract IgE epitope mAb-bound plate in sandwich combination with gold probe for sensitive and rapid detection of bovine β-lactoglobulin and its potentially allergenic residues.

Molecular Diagnosis of Invasive Aspergillosis and Detection of Azole Resistance by a Newly Commercialized PCR Kit

PubMed Central

Gabriel, Frédéric; Gaboyard, Manuel; Lagardere, Gaëlle; Audebert, Lucile; Quesne, Gilles; Godichaud, Sandrine; Verweij, Paul E.; Accoceberry, Isabelle

2017-01-01

ABSTRACT Aspergillus fumigatus is the main species responsible for aspergillosis in humans. The diagnosis of aspergillosis remains difficult, and the rapid emergence of azole resistance in A. fumigatus is worrisome. The aim of this study was to validate the new MycoGENIE A. fumigatus real-time PCR kit and to evaluate its performance on clinical samples for the detection of A. fumigatus and its azole resistance. This multiplex assay detects DNA from the A. fumigatus species complex by targeting the multicopy 28S rRNA gene and specific TR34 and L98H mutations in the single-copy-number cyp51A gene of A. fumigatus. The specificity of cyp51A mutation detection was assessed by testing DNA samples from 25 wild-type or mutated clinical A. fumigatus isolates. Clinical validation was performed on 88 respiratory samples obtained from 62 patients and on 69 serum samples obtained from 16 patients with proven or probable aspergillosis and 13 patients without aspergillosis. The limit of detection was <1 copy for the Aspergillus 28S rRNA gene and 6 copies for the cyp51A gene harboring the TR34 and L98H alterations. No cross-reactivity was detected with various fungi and bacteria. All isolates harboring the TR34 and L98H mutations were accurately detected by quantitative PCR (qPCR) analysis. With respiratory samples, qPCR results showed a sensitivity and specificity of 92.9% and 90.1%, respectively, while with serum samples, the sensitivity and specificity were 100% and 84.6%, respectively. Our study demonstrated that this new real-time PCR kit enables sensitive and rapid detection of A. fumigatus DNA and azole resistance due to TR34 and L98H mutations in clinical samples. PMID:28814586

Matrix-assisted laser desorption/ionization mass spectrometric analysis of poly(3,4-ethylenedioxythiophene) in solid-state dye-sensitized solar cells: comparison of in situ photoelectrochemical polymerization in aqueous micellar and organic media.

PubMed

Zhang, Jinbao; Ellis, Hanna; Yang, Lei; Johansson, Erik M J; Boschloo, Gerrit; Vlachopoulos, Nick; Hagfeldt, Anders; Bergquist, Jonas; Shevchenko, Denys

2015-04-07

Solid-state dye-sensitized solar cells (sDSCs) are devoid of such issues as electrolyte evaporation or leakage and electrode corrosion, which are typical for traditional liquid electrolyte-based DSCs. Poly(3,4-ethylenedioxythiophene) (PEDOT) is one of the most popular and efficient p-type conducting polymers that are used in sDSCs as a solid-state hole-transporting material. The most convenient way to deposit this insoluble polymer into the dye-sensitized mesoporous working electrode is in situ photoelectrochemical polymerization. Apparently, the structure and the physicochemical properties of the generated conducting polymer, which determine the photovoltaic performance of the corresponding solar cell, can be significantly affected by the preparation conditions. Therefore, a simple and fast analytical method that can reveal information on polymer chain length, possible chemical modifications, and impurities is strongly required for the rapid development of efficient solar energy-converting devices. In this contribution, we applied matrix-assisted laser desorption/ionization mass spectrometry (MALDI MS) for the analysis of PEDOT directly on sDSCs. It was found that the PEDOT generated in aqueous micellar medium possesses relatively shorter polymeric chains than the PEDOT deposited from an organic medium. Furthermore, the micellar electrolyte promotes a transformation of one of the thiophene terminal units to thiophenone. The introduction of a carbonyl group into the PEDOT molecule impedes the growth of the polymer chain and reduces the conductivity of the final polymer film. Both the simplicity of sample preparation (only application of the organic matrix onto the solar cell is needed) and the rapidity of analysis hold the promise of making MALDI MS an essential tool for the physicochemical characterization of conducting polymer-based sDSCs.

Method for rapid isolation of sensitive mutants

DOEpatents

Freyer, James P.

1997-01-01

Sensitive mammalian cell mutants are rapidly isolated using flow cytometry. A first population of clonal spheroids is established to contain both normal and mutant cells. The population may be naturally occurring or may arise from mutagenized cells. The first population is then flow sorted by size to obtain a second population of clonal spheroids of a first uniform size. The second population is then exposed to a DNA-damaging agent that is being investigated. The exposed second population is placed in a growth medium to form a third population of clonal spheroids comprising spheroids of increased size from the mammalian cells that are resistant to the DNA-damaging agent and spheroids of substantially the first uniform size formed from the mammalian cells that are sensitive to the DNA-damaging agent. The third population is not flow sorted to differentiate the spheroids formed from resistant mammalian cells from spheroids formed from sensitive mammalian cells. The spheroids formed from sensitive mammalian cells are now treated to recover viable sensitive cells from which a sensitive cell line can be cloned.

Method for rapid isolation of sensitive mutants

DOEpatents

Freyer, J.P.

1997-07-29

Sensitive mammalian cell mutants are rapidly isolated using flow cytometry. A first population of clonal spheroids is established to contain both normal and mutant cells. The population may be naturally occurring or may arise from mutagenized cells. The first population is then flow sorted by size to obtain a second population of clonal spheroids of a first uniform size. The second population is then exposed to a DNA-damaging agent that is being investigated. The exposed second population is placed in a growth medium to form a third population of clonal spheroids comprising spheroids of increased size from the mammalian cells that are resistant to the DNA-damaging agent and spheroids of substantially the first uniform size formed from the mammalian cells that are sensitive to the DNA-damaging agent. The third population is not flow sorted to differentiate the spheroids formed from resistant mammalian cells from spheroids formed from sensitive mammalian cells. The spheroids formed from sensitive mammalian cells are now treated to recover viable sensitive cells from which a sensitive cell line can be cloned. 15 figs.

Improvement of the antiproliferative effect of rapamycin on tumor cell lines by poly (monomethylitaconate)-based pH-sensitive, plasma stable liposomes.

PubMed

Ghanbarzadeh, Saeed; Arami, Sanam; Pourmoazzen, Zhaleh; Khorrami, Arash

2014-03-01

pH-responsive polymers produce liposomes with pH-sensitive property which can release their encapsulated drug under mild acidic conditions found inside the cellular endosomes, inflammatory tissues and cancerous cells. The aim of this study was preparing pH-sensitive and plasma stable liposomes in order to enhance the selectivity and antiproliferative effect of Rapamycin. In the present study we used PEG-poly (monomethylitaconate)-CholC6 (PEG-PMMI-CholC6) copolymer and Oleic acid (OA) to induce pH-sensitive property in Rapamycin liposomes. pH-sensitive liposomal formulations bearing copolymer PEG-PMMI-CholC6 and OA were characterized in regard to physicochemical stability, pH-responsiveness and stability in human plasma. The ability of pH-sensitive liposomes in enhancing the cytotoxicity of Rapamycin was evaluated in vitro by using colon cancer cell line (HT-29) and compared with its cytotoxicity on human umbilical vein endothelial cell (HUVEC) line. Both formulations were found to release their contents under mild acidic conditions rapidly. However, unlike OA-based liposomes, the PEG-PMMI-CholC6 bearing liposomes preserved their pH-sensitivity in plasma. Both types of pH-sensitive Rapamycin-loaded liposomes exhibited high physicochemical stability and could deliver antiproliferative agent into HT-29 cells much more efficiently in comparison with conventional liposomes. Conversely, the antiproliferative effect of pH-sensitive liposomes on HUVEC cell line was less than conventional liposomes. This study showed that both OA and PEG-PMMI-CholC6-based vesicles could submit pH-sensitive property, however, only PEG-PMMI-CholC6-based liposomes could preserve pH-sensitive property after incubation in plasma. As a result pH-sensitive PEG-PMMI-CholC6-based liposomal formulation can improve the selectivity, stability and antiproliferative effect of Rapamycin. Copyright © 2014 Elsevier B.V. All rights reserved.

Highly sensitive self-complementary DNA nanoswitches triggered by polyelectrolytes

NASA Astrophysics Data System (ADS)

Wu, Jincai; Yu, Feng; Zhang, Zheng; Chen, Yong; Du, Jie; Maruyama, Atsushi

2015-12-01

Dimerization of two homologous strands of genomic DNA/RNA is an essential feature of retroviral replication. Herein we show that a cationic comb-type copolymer (CCC), poly(l-lysine)-graft-dextran, accelerates the dimerization of self-complementary stem-loop DNA, frequently found in functional DNA/RNA molecules, such as aptamers. Furthermore, an anionic polymer poly(sodium vinylsulfonate) (PVS) dissociates CCC from the duplex shortly within a few seconds. Then single stem-loop DNA spontaneously transforms from its dimer. Thus we can easily control the dimer and stem-loop DNA by switching on/off CCC activity. Both polyelectrolytes and DNA concentrations are in the nanomole per liter range. The polyelectrolyte-assisted transconformation and sequences design strategy ensures the reversible state control with rapid response and effective switching under physiologically relevant conditions. A further application of this sensitive assembly is to construct an aptamer-type drug delivery system, bind or release functional molecules responding to its transconformation.Dimerization of two homologous strands of genomic DNA/RNA is an essential feature of retroviral replication. Herein we show that a cationic comb-type copolymer (CCC), poly(l-lysine)-graft-dextran, accelerates the dimerization of self-complementary stem-loop DNA, frequently found in functional DNA/RNA molecules, such as aptamers. Furthermore, an anionic polymer poly(sodium vinylsulfonate) (PVS) dissociates CCC from the duplex shortly within a few seconds. Then single stem-loop DNA spontaneously transforms from its dimer. Thus we can easily control the dimer and stem-loop DNA by switching on/off CCC activity. Both polyelectrolytes and DNA concentrations are in the nanomole per liter range. The polyelectrolyte-assisted transconformation and sequences design strategy ensures the reversible state control with rapid response and effective switching under physiologically relevant conditions. A further application of this sensitive assembly is to construct an aptamer-type drug delivery system, bind or release functional molecules responding to its transconformation. Electronic supplementary information (ESI) available: I. Sequences of DIS25, DIS25-2a and DIS25-3a. II. Structural formula of poly(l-lysine)-graft-dextran (PLL-g-Dex). 1H-NMR spectra of PLL-g-Dex in D2O. III. Gel electrophoretic analysis of dimerization of DIS25 with various N/P ratios. IV. The effect of polyelectrolyte on the fluorescence polarity of TAMRA-labeled duplex. V. UV absorption/Tm profiles of DIS25. VI. Arrhenius plots for spontaneous dissociation of the DIS25 dimer and PLL-g-Dex-assisted dimerization of DIS25.VII. Switching between double stem-loop DIS42 and extended multiplex drived by PLL-g-Dex and PVS. See DOI: 10.1039/c5nr05193b

A rapid molecular diagnosis of cutaneous leishmaniasis by colorimetric malachite green-loop-mediated isothermal amplification (LAMP) combined with an FTA card as a direct sampling tool.

PubMed

Nzelu, Chukwunonso O; Cáceres, Abraham G; Guerrero-Quincho, Silvia; Tineo-Villafuerte, Edwin; Rodriquez-Delfin, Luis; Mimori, Tatsuyuki; Uezato, Hiroshi; Katakura, Ken; Gomez, Eduardo A; Guevara, Angel G; Hashiguchi, Yoshihisa; Kato, Hirotomo

2016-01-01

Leishmaniasis remains one of the world's most neglected diseases, and early detection of the infectious agent, especially in developing countries, will require a simple and rapid test. In this study, we established a quick, one-step, single-tube, highly sensitive loop-mediated isothermal amplification (LAMP) assay for rapid detection of Leishmania DNA from tissue materials spotted on an FTA card. An FTA-LAMP with pre-added malachite green was performed at 64°C for 60min using a heating block and/or water bath and DNA amplification was detected immediately after incubation. The LAMP assay had high detection sensitivity down to a level of 0.01 parasites per μl. The field- and clinic-applicability of the colorimetric FTA-LAMP assay was demonstrated with 122 clinical samples collected from patients suspected of having cutaneous leishmaniasis in Peru, from which 71 positives were detected. The LAMP assay in combination with an FTA card described here is rapid and sensitive, as well as simple to perform, and has great potential usefulness for diagnosis and surveillance of leishmaniasis in endemic areas. Copyright © 2015 Elsevier B.V. All rights reserved.

Adiabatic Compression Sensitivity of Liquid Fuels and Monopropellants

NASA Technical Reports Server (NTRS)

Ismail, Ismail M. K.; Hawkins, Tom W.

2000-01-01

Liquid rocket propellants can be sensitive to rapid compression. Such liquids may undergo decomposition and their handling may be accompanied with risk. Decomposition produces small gas bubbles in the liquid, which upon rapid compression may cause catastrophic explosions. The rapid compression can result from mechanical shocks applied on the tank containing the liquid or from rapid closure of the valves installed on the lines. It is desirable to determine the conditions that may promote explosive reactions. At Air Force Research Laboratory (AFRL), we constructed an apparatus and established a safe procedure for estimating the sensitivity of propellant materials towards mechanical shocks (Adiabatic Compression Tester). A sample is placed on a stainless steel U-tube, held isothermally at a temperature between 20 and 150 C then exposed to an abrupt mechanical shock of nitrogen gas at a pressure between 6.9 and 20.7 MPa (1000 to 3000 psi). The apparatus is computer interfaced and is driven with LABTECH NOTEBOOK-pro (registered) Software. In this presentation, the design of the apparatus is shown, the operating procedure is outlined, and the safety issues are addressed. The results obtained on different energetic materials are presented.

Noninvasive type 2 diabetes screening: superior sensitivity to fasting plasma glucose and A1C.

PubMed

Maynard, John D; Rohrscheib, Mark; Way, Jeffrey F; Nguyen, Catriona M; Ediger, Marwood N

2007-05-01

This study compared the performance of a novel noninvasive technology to fasting plasma glucose (FPG) and A1C tests for detecting undiagnosed diabetes and impaired glucose tolerance. The design was a head-to-head evaluation in a naïve population. Consented subjects received FPG and A1C tests and an oral glucose tolerance test (OGTT). Subjects were also measured by a noninvasive device that detects the fluorescence of skin advanced glycation end products. A total of 351 subjects participated. Subjects with 2-h OGTT values > or = 140 mg/dl defined the positive screening class. A total of 84 subjects (23.9% prevalence) screened positive. The performances of the noninvasive device, FPG, and A1C were evaluated for sensitivity and specificity against this classification. At the impaired fasting glucose threshold (FPG = 100 mg/dl), the FPG testing sensitivity was 58% and the specificity was 77.4%. At that same specificity, the sensitivity for A1C testing was 63.8%, while the noninvasive testing sensitivity was 74.7%. The sensitivity advantage of the noninvasive device over both blood tests for detecting diabetes and precursors was statistically significant (P < 0.05). The noninvasive technology showed clinical performance advantages over both FPG and A1C testing. The sensitivity differential indicated that the noninvasive device is capable of identifying 28.8% more individuals in the OGTT-defined positive screening class than FPG testing and 17.1% more than A1C testing. The combination of higher sensitivity and greater convenience--rapid results with no fasting or blood draws--makes the device well suited for opportunistic screening.

Rapid genetic typing of diarrheagenic Escherichia coli using a two-tube modified molecular beacon based multiplex real-time PCR assay and its clinical application

PubMed Central

2014-01-01

Background Diarrheagenic Escherichia coli (DEC), including Enterotoxigenic E.coli (ETEC), Enteroaggregative E.coli (EAEC), Enteropathogenic E.coli (EPEC), Enterohemolysin E.coli (EHEC) and Enteroinvasive E.coli (EIEC) causes diarrhea or hemolytic uremic syndromes among infants and travelers around the world. A rapid, reliable and repeatable method is urgent for identifying DEC so as to provide the reference for responding to diarrheal disease outbreak and the treatment of the diarrheal patients associated with DEC. Methods In this study, specific primers and modified molecular beacon probes of nine specific virulence genes, whose 5′end were added with homo tail sequence, were designed; and a two-tube modified molecular beacon based multiplex real–time PCR (rtPCR) assay for the identification of five Escherichia coli pathotypes, including ETEC, EAEC, EPEC, EHEC and EIEC was developed and optimized. Totally 102 bacterial strains, including 52 reference bacterial strains and 50 clinical strains were detected to confirm whether the target genes selected were specific. Then detection limits of the assay were tested. Lastly, the assay was applied to the detection of 11860 clinical samples to evaluate the specificity and sensitivity of the developed assay compared with the conventional PCR. Results The target genes were 100% specific as assessed on 102 bacterial strains since no cross-reactions were observed. The detection limits ranged from 88 CFU/mL (EHEC) to 880 CFU/mL (EPEC). Compared with the conventional PCR, the specificity and sensitivity of the multiplex rtPCR was 100% and over 99%, respectively. The coefficient of variation (CV) for each target gene ranged from 0.45% to 1.53%. 171 positive clinical samples were mostly identified as ETEC (n = 111, 64.9%) and EPEC (n = 38, 22.2%), which were the dominating pathotypes of DEC strains. Conclusion The developed multiplex rtPCR assay for the identification of DEC was high sensitive and specific and could be applied to the rapid identification of DEC in clinical and public health laboratories. PMID:25023669

Multicultural Experience and Intercultural Sensitivity among South Korean Adolescents

ERIC Educational Resources Information Center

Park, Jung-Suh

2013-01-01

This study examined experience with multicultural contact and the intercultural sensitivity of majority adolescents in South Korean society, one that is rapidly shifting toward a more multicultural environment. It also analyzed the influence of these multicultural experiences on intercultural sensitivity. The results of the analysis revealed a…

Ablation of capsaicin sensitive afferent nerves impairs defence but not rapid repair of rat gastric mucosa.

PubMed

Pabst, M A; Schöninkle, E; Holzer, P

1993-07-01

Capsaicin sensitive afferent neurones have previously been reported to play a part in gastric mucosal protection. The aim of this study was to investigate whether these nociceptive neurones strengthen mucosal defence against injury or promote rapid repair of the damaged mucosa, or both. This hypothesis was examined in anaesthetised rats whose stomachs were perfused with ethanol (25 or 50% in saline, wt/wt) for 30 minutes. The gastric mucosa was inspected 0 and 180 minutes after ethanol had been given at the macroscopic, light, and scanning electron microscopic level. Rapid repair of the ethanol injured gastric mucosa (reduction of deep injury, partial re-epithelialisation of the denuded surface) took place in rats anaesthetised with phenobarbital, but not in those anaesthetised with urethane. Afferent nerve ablation as a result of treating rats with a neurotoxic dose of capsaicin before the experiment significantly aggravated ethanol induced damage as shown by an increase in the area and depth of mucosal erosions. Rapid repair of the injured mucosa, however, as seen in rats anesthetised with phenobarbital 180 minutes after ethanol was given, was similar in capsaicin and vehicle pretreated animals. Ablation of capsaicin sensitive afferent neurones was verified by a depletion of calcitonin gene related peptide from the gastric corpus wall. These findings indicate that nociceptive neurones control mechanisms of defence against acute injury but are not required for rapid repair of injured mucosa.

Regulation of intracellular pH in the rabbit cortical collecting tubule.

PubMed Central

Weiner, I D; Hamm, L L

1990-01-01

The cortical collecting tubule (CCT) is an important nephron segment for Na+, K+, water and acid-base transport. Differential loading characteristics of the pH sensitive dye 2',7'-bis-(2-carboxyethyl)-5(and-6)carboxyfluorescein (BCECF) and basolateral Cl- removal were used to identify and study intracellular pH (pHi) regulation in each of three cell types involved in this transport. Both principal cells and beta-intercalated cells were found to have a basolateral Na+/H+ exchanger based on the Na+ and amiloride sensitivity of pHi recovery from acid loads. Intercalated cells demonstrated abrupt pHi changes with basolateral Cl- removal. alpha-intercalated cells alkalinized; beta-intercalated cells acidified. In the beta-intercalated cells, luminal Cl- removal blocked changes in pHi in response to changes in luminal HCO3- or peritubular Cl-, providing direct evidence for a luminal Cl-/HCO3- exchanger. In principal cells, brief removal of either peritubular or luminal Cl- resulted in no change in pHi; however, return of peritubular Cl- after prolonged removal resulted in a rapid fall in pHi consistent with a basolateral Cl-/HCO3- exchanger, which may be relatively inactive under baseline conditions. Therefore, Cl-/HCO3- exchange is present in all three cell types but varies in location and activity. PMID:2153152

Circulating tumor cell detection: A direct comparison between negative and unbiased enrichment in lung cancer.

PubMed

Xu, Yan; Liu, Biao; Ding, Fengan; Zhou, Xiaodie; Tu, Pin; Yu, Bo; He, Yan; Huang, Peilin

2017-06-01

Circulating tumor cells (CTCs), isolated as a 'liquid biopsy', may provide important diagnostic and prognostic information. Therefore, rapid, reliable and unbiased detection of CTCs are required for routine clinical analyses. It was demonstrated that negative enrichment, an epithelial marker-independent technique for isolating CTCs, exhibits a better efficiency in the detection of CTCs compared with positive enrichment techniques that only use specific anti-epithelial cell adhesion molecules. However, negative enrichment techniques incur significant cell loss during the isolation procedure, and as it is a method that uses only one type of antibody, it is inherently biased. The detection procedure and identification of cell types also relies on skilled and experienced technicians. In the present study, the detection sensitivity of using negative enrichment and a previously described unbiased detection method was compared. The results revealed that unbiased detection methods may efficiently detect >90% of cancer cells in blood samples containing CTCs. By contrast, only 40-60% of CTCs were detected by negative enrichment. Additionally, CTCs were identified in >65% of patients with stage I/II lung cancer. This simple yet efficient approach may achieve a high level of sensitivity. It demonstrates a potential for the large-scale clinical implementation of CTC-based diagnostic and prognostic strategies.

HSP72 is a mitochondrial stress sensor critical for Parkin action, oxidative metabolism, and insulin sensitivity in skeletal muscle.

PubMed

Drew, Brian G; Ribas, Vicente; Le, Jamie A; Henstridge, Darren C; Phun, Jennifer; Zhou, Zhenqi; Soleymani, Teo; Daraei, Pedram; Sitz, Daniel; Vergnes, Laurent; Wanagat, Jonathan; Reue, Karen; Febbraio, Mark A; Hevener, Andrea L

2014-05-01

Increased heat shock protein (HSP) 72 expression in skeletal muscle prevents obesity and glucose intolerance in mice, although the underlying mechanisms of this observation are largely unresolved. Herein we show that HSP72 is a critical regulator of stress-induced mitochondrial triage signaling since Parkin, an E3 ubiquitin ligase known to regulate mitophagy, was unable to ubiquitinate and control its own protein expression or that of its central target mitofusin (Mfn) in the absence of HSP72. In wild-type cells, we show that HSP72 rapidly translocates to depolarized mitochondria prior to Parkin recruitment and immunoprecipitates with both Parkin and Mfn2 only after specific mitochondrial insult. In HSP72 knockout mice, impaired Parkin action was associated with retention of enlarged, dysmorphic mitochondria and paralleled by reduced muscle respiratory capacity, lipid accumulation, and muscle insulin resistance. Reduced oxygen consumption and impaired insulin action were recapitulated in Parkin-null myotubes, confirming a role for the HSP72-Parkin axis in the regulation of muscle insulin sensitivity. These data suggest that strategies to maintain HSP72 may provide therapeutic benefit to enhance mitochondrial quality and insulin action to ameliorate complications associated with metabolic diseases, including type 2 diabetes.

Neutral endopeptidase promotes phorbol ester-induced apoptosis in prostate cancer cells by inhibiting neuropeptide-induced protein kinase C delta degradation.

PubMed

Sumitomo, M; Shen, R; Goldberg, J S; Dai, J; Navarro, D; Nanus, D M

2000-12-01

Phorbol esters induce apoptosis in androgen-sensitive LNCaP cells, which express neutral endopeptidase (NEP), but not in androgen-independent prostate cancer (PC) cells, which lack NEP expression. We investigated the role of NEP in PC cell susceptibility to 12-O-tetradecanoylphorbol-13-acetate (TPA). Western analysis showed that expression of NEP and protein kinase Cdelta (PKCdelta) correlated with PC cell sensitivity to TPA-induced growth arrest and apoptosis in LNCaP cells and in TSU-Prl cells expressing an inducible wild-type NEP protein. Inhibition of NEP enzyme activity using the specific NEP inhibitor CGS24592, or inhibition of PKCdelta using Rottlerin at concentrations that inhibit PKCdelta but not PKCalpha, significantly inhibited TPA-induced growth inhibition and cell death. Furthermore, pulse-chase experiments showed PKCdelta is stabilized in LNCaP cells and in TSU-Pr1 cells overexpressing wild-type NEP compared with PC cells lacking NEP expression. This results from NEP inactivation of its neuropeptide substrates (bombesin and endothelin-1), which in the absence of NEP stimulate cSrc kinase activity and induce rapid degradation of PKCdelta protein. These results indicate that expression of enzymatically active NEP by PC cells is necessary for TPA-induced apoptosis, and that NEP inhibits neuropeptide-induced, cSrc-mediated PKCdelta degradation.

Mitochondria and NMDA Receptor-Dependent Toxicity of Berberine Sensitizes Neurons to Glutamate and Rotenone Injury

PubMed Central

Kysenius, Kai; Brunello, Cecilia A.; Huttunen, Henri J.

2014-01-01

The global incidence of metabolic and age-related diseases, including type 2 diabetes and Alzheimer's disease, is on the rise. In addition to traditional pharmacotherapy, drug candidates from complementary and alternative medicine are actively being pursued for further drug development. Berberine, a nutraceutical traditionally used as an antibiotic, has recently been proposed to act as a multi-target protective agent against type 2 diabetes, dyslipidemias, ischemic brain injury and neurodegenerative diseases, such as Parkinson's and Alzheimer's disease. However, the safety profile of berberine remains controversial, as isolated reports suggest risks with acute toxicity, bradycardia and exacerbation of neurodegeneration. We report that low micromolar berberine causes rapid mitochondria-dependent toxicity in primary neurons characterized by mitochondrial swelling, increased oxidative stress, decreased mitochondrial membrane potential and depletion of ATP content. Berberine does not induce caspase-3 activation and the resulting neurotoxicity remains unaffected by pan-caspase inhibitor treatment. Interestingly, inhibition of NMDA receptors by memantine and MK-801 completely blocked berberine-induced neurotoxicity. Additionally, subtoxic nanomolar concentrations of berberine were sufficient to sensitize neurons to glutamate excitotoxicity and rotenone injury. Our study highlights the need for further safety assessment of berberine, especially due to its tendency to accumulate in the CNS and the risk of potential neurotoxicity as a consequence of increasing bioavailability of berberine. PMID:25192195

A dynamic sandwich assay on magnetic beads for selective detection of single-nucleotide mutations at room temperature.

PubMed

Wang, Junxiu; Xiong, Guoliang; Ma, Liang; Wang, Shihui; Zhou, Xu; Wang, Lei; Xiao, Lehui; Su, Xin; Yu, Changyuan

2017-08-15

Single-nucleotide mutation (SNM) has proven to be associated with a variety of human diseases. Development of reliable methods for the detection of SNM is crucial for molecular diagnosis and personalized medicine. The sandwich assays are widely used tools for detecting nucleic acid biomarkers due to their low cost and rapid signaling. However, the poor hybridization specificity of signal probe at room temperature hampers the discrimination of mutant and wild type. Here, we demonstrate a dynamic sandwich assay on magnetic beads for SNM detection based on the transient binding between signal probe and target. By taking the advantage of mismatch sensitive thermodynamics of transient DNA binding, the dynamic sandwich assay exhibits high discrimination factor for mutant with a broad range of salt concentration at room temperature. The beads used in this assay serve as a tool for separation, and might be helpful to enhance SNM selectivity. Flexible design of signal probe and facile magnetic separation allow multiple-mode downstream analysis including colorimetric detection and isothermal amplification. With this method, BRAF mutations in the genomic DNA extracted from cancer cell lines were tested, allowing sensitive detection of SNM at very low abundances (0.1-0.5% mutant/wild type). Copyright © 2017 Elsevier B.V. All rights reserved.

Comparing rapid methods for detecting Listeria in seafood and environmental samples using the most probably number (MPN) technique.

PubMed

Cruz, Cristina D; Win, Jessicah K; Chantarachoti, Jiraporn; Mutukumira, Anthony N; Fletcher, Graham C

2012-02-15

The standard Bacteriological Analytical Manual (BAM) protocol for detecting Listeria in food and on environmental surfaces takes about 96 h. Some studies indicate that rapid methods, which produce results within 48 h, may be as sensitive and accurate as the culture protocol. As they only give presence/absence results, it can be difficult to compare the accuracy of results generated. We used the Most Probable Number (MPN) technique to evaluate the performance and detection limits of six rapid kits for detecting Listeria in seafood and on an environmental surface compared with the standard protocol. Three seafood products and an environmental surface were inoculated with similar known cell concentrations of Listeria and analyzed according to the manufacturers' instructions. The MPN was estimated using the MPN-BAM spreadsheet. For the seafood products no differences were observed among the rapid kits and efficiency was similar to the BAM method. On the environmental surface the BAM protocol had a higher recovery rate (sensitivity) than any of the rapid kits tested. Clearview™, Reveal®, TECRA® and VIDAS® LDUO detected the cells but only at high concentrations (>10(2) CFU/10 cm(2)). Two kits (VIP™ and Petrifilm™) failed to detect 10(4) CFU/10 cm(2). The MPN method was a useful tool for comparing the results generated by these presence/absence test kits. There remains a need to develop a rapid and sensitive method for detecting Listeria in environmental samples that performs as well as the BAM protocol, since none of the rapid tests used in this study achieved a satisfactory result. Copyright © 2011 Elsevier B.V. All rights reserved.

Operational feasibility of using whole blood in the rapid HIV testing algorithm of a resource-limited settings like Bangladesh.

PubMed

Munshi, Saif U; Oyewale, Tajudeen O; Begum, Shahnaz; Uddin, Ziya; Tabassum, Shahina

2016-03-01

Serum-based rapid HIV testing algorithm in Bangladesh constitutes operational challenge to scaleup HIV testing and counselling (HTC) in the country. This study explored the operational feasibility of using whole blood as alternative to serum for rapid HIV testing in Bangladesh. Whole blood specimens were collected from two study groups. The groups included HIV-positive patients (n = 200) and HIV-negative individuals (n = 200) presenting at the reference laboratory in Dhaka, Bangladesh. The specimens were subjected to rapid HIV tests using the national algorithm with A1 = Alere Determine (United States), A2 = Uni-Gold (Ireland), and A3 = First Response (India). The sensitivity and specificity of the test results, and the operational cost were compared with current serum-based testing. The sensitivities [95% of confidence interval (CI)] for A1, A2, and A3 tests using whole blood were 100% (CI: 99.1-100%), 100% (CI: 99.1-100%), and 97% (CI: 96.4-98.2%), respectively, and specificities of all test kits were 100% (CI: 99.1-100%). Significant (P < 0.05) reduction in the cost of establishing HTC centre and consumables by 94 and 61%, respectively, were observed. The cost of administration and external quality assurance reduced by 39 and 43%, respectively. Overall, there was a 36% cost reduction in total operational cost of rapid HIV testing with blood when compared with serum. Considering the similar sensitivity and specificity of the two specimens, and significant cost reduction, rapid HIV testing with whole blood is feasible. A review of the national HIV rapid testing algorithm with whole blood will contribute toward improving HTC coverage in Bangladesh.

Some new speculative ideas about the “behavioral homeostasis theory” as to how the simple learned behaviors of habituation and sensitization improve organism survival throughout phylogeny

PubMed Central

Eisenstein, Edward M.; Eisenstein, Doris L.; Sarma, Jonnalagedda Sarma M.; Knapp, Herschel; Smith, James C.

2012-01-01

This paper explores further the “behavioral homeostasis theory” (BHT) regarding the evolutionary significance for organism survival of the two simple non-associative rapidly learned behaviors of habituation and sensitization. The BHT postulates that the evolutionary function of habituation and sensitization throughout phylogeny is to rapidly maximize an organism’s overall readiness to cope with new stimuli and to minimize unnecessary energy expenditure. These behaviors have survived with remarkable similarity throughout phylogeny from aneural protozoa to humans. The concept of “behavioral homeostasis” emphasizes that the homeostatic process is more than just maintaining internal equilibrium in the face of changing internal and external conditions. It emphasizes the rapid internal and external effector system changes that occur to optimize organism readiness to cope with any new external stimulus situation. Truly life-threatening stimuli elicit instinctive behavior such as fight, flee, or hide. If the stimulus is not life-threatening, the organism rapidly learns to adjust to an appropriate level of overall responsiveness over stimulus repetitions. The rapid asymptotic level approached by those who decrease their overall responsiveness to the second stimulus (habituaters) and those who increase their overall responsiveness to an identical second stimulus (sensitizers) not only optimizes readiness to cope with any new stimulus situation but also reduces unnecessary energy expenditure. This paper is based on a retrospective analysis of data from 4 effector system responses to eight repetitive tone stimuli in adult human males. The effector systems include the galvanic skin response, finger pulse volume, muscle frontalis and heart rate. The new information provides the basis for further exploration of the BHT including new predictions and proposed relatively simple experiments to test them. PMID:22896782

Clinical Application of Picodroplet Digital PCR Technology for Rapid Detection of EGFR T790M in Next-Generation Sequencing Libraries and DNA from Limited Tumor Samples.

PubMed

Borsu, Laetitia; Intrieri, Julie; Thampi, Linta; Yu, Helena; Riely, Gregory; Nafa, Khedoudja; Chandramohan, Raghu; Ladanyi, Marc; Arcila, Maria E

2016-11-01

Although next-generation sequencing (NGS) is a robust technology for comprehensive assessment of EGFR-mutant lung adenocarcinomas with acquired resistance to tyrosine kinase inhibitors, it may not provide sufficiently rapid and sensitive detection of the EGFR T790M mutation, the most clinically relevant resistance biomarker. Here, we describe a digital PCR (dPCR) assay for rapid T790M detection on aliquots of NGS libraries prepared for comprehensive profiling, fully maximizing broad genomic analysis on limited samples. Tumor DNAs from patients with EGFR-mutant lung adenocarcinomas and acquired resistance to epidermal growth factor receptor inhibitors were prepared for Memorial Sloan-Kettering-Integrated Mutation Profiling of Actionable Cancer Targets sequencing, a hybrid capture-based assay interrogating 410 cancer-related genes. Precapture library aliquots were used for rapid EGFR T790M testing by dPCR, and results were compared with NGS and locked nucleic acid-PCR Sanger sequencing (reference high sensitivity method). Seventy resistance samples showed 99% concordance with the reference high sensitivity method in accuracy studies. Input as low as 2.5 ng provided a sensitivity of 1% and improved further with increasing DNA input. dPCR on libraries required less DNA and showed better performance than direct genomic DNA. dPCR on NGS libraries is a robust and rapid approach to EGFR T790M testing, allowing most economical utilization of limited material for comprehensive assessment. The same assay can also be performed directly on any limited DNA source and cell-free DNA. Copyright © 2016 American Society for Investigative Pathology and the Association for Molecular Pathology. Published by Elsevier Inc. All rights reserved.

Applicability of ambient toxicity testing to national or regional water-quality assessment

USGS Publications Warehouse

Elder, J.F.

1989-01-01

Comprehensive assessment of the quality of natural waters requires a multifaceted approach. Based on experimentation designed to monitor responses of organisms to environmental stresses, toxicity testing may have diverse purposes in water quality assessments. These purposes may include identification that warrant further study because of poor water quality or unusual ecological features, verification of other types of monitoring, or assessment of contaminant effects on aquatic communities. A wide variety of toxicity test methods have been developed to fulfill the needs of diverse applications. The methods differ primarily in the full selections made relative to four characteristics: (1) test species, (2) endpoints (acute or chronic), (3) test enclosure type, and (4) test substance (toxicant) that functions as the environmental stress. Toxicity test approachs vary in their capacity to meet the needs of large-scale assessments of existing water quality. Ambient testing is more likely to meet these needs than are the procedures that call for exposure of the test organisms to known concentrations of a single toxicant. However, meaningful interpretation of ambient test results depend on the existence of accompanying chemical analysis of the ambient media. The ambient test substance may be water or sediments. Sediment tests have had limited application, but they are useful because of the fact that most toxicants tend to accumulate in sediments, and many test species either inhabit the sediments or are in frequent contact with them. Biochemical testing methods, which have been developing rapidly in recent years, are likely to be among the most useful procedures for large-scale water quality assessments. They are relatively rapid and simple, and more importantly, they focus on biochemical changes that are the initial responses of virtually all organisms to environmental stimuli. Most species are sensitive to relatively few toxicants and their sensitivities vary as conditions change. One of the most informative approaches for toxicity testing is to combine biochemical tests with other test methods in a ' battery or tests ' that is diversified enough to characterize different types of toxicants and different trophic levels. (Lantz-PTT)

Structure-activity relationships for the action of 11 pyrethroid insecticides on rat Na{sub v}1.8 sodium channels expressed in Xenopus oocytes

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

Choi, J.-S.; Soderlund, David M.

2006-03-15

Pyrethroid insecticides bind to voltage-sensitive sodium channels and modify their gating kinetics, thereby disrupting nerve function. This paper describes the action of 11 structurally diverse commercial pyrethroid insecticides on the rat Na{sub v}1.8 sodium channel isoform, the principal carrier of the tetrodotoxin-resistant, pyrethroid-sensitive sodium current of sensory neurons, expressed in Xenopus laevis oocytes. All 11 compounds produced characteristic sodium tail currents following a depolarizing pulse that ranged from rapidly-decaying monoexponential currents (allethrin, cismethrin and permethrin) to persistent biexponential currents (cyfluthrin, cyhalothrin, cypermethrin and deltamethrin). Tail currents for the remaining compounds (bifenthrin, fenpropathrin, fenvalerate and tefluthrin) were monoexponential and decayed withmore » kinetics intermediate between these extremes. Reconstruction of currents carried solely by the pyrethroid-modified subpopulation of channels revealed two types of pyrethroid-modified currents. The first type, found with cismethrin, allethrin, permethrin and tefluthrin, activated relatively rapidly and inactivated partially during a 40-ms depolarization. The second type, found with cypermethrin, cyfluthrin, cyhalothrin, deltamethrin, fenpropathrin and fenvalerate, activated more slowly and did not detectably inactivate during a 40-ms depolarization. Only bifenthrin did not produce modified currents that fit clearly into either of these categories. In all cases, the rate of activation of modified channels was strongly correlated with the rate of tail current decay following repolarization. Modification of Na{sub v}1.8 sodium channels by cyfluthrin, cyhalothrin, cypermethrin and deltamethrin was enhanced 2.3- to 3.4-fold by repetitive stimulation; this effect appeared to result from the accumulation of persistently open channels rather than preferential binding to open channel states. Fenpropathrin was the most effective compound against Na{sub v}1.8 sodium channels from the perspective of either resting or use-dependent modification. When use dependence is taken into account, cypermethrin, deltamethrin and tefluthrin approached the effectiveness of fenpropathrin. The selective expression of Na{sub v}1.8 sodium channels in nociceptive neurons suggests that these channels may be important targets for pyrethroids in the production of paresthesia following dermal expo0010su.« less

Excision repair of UV radiation-induced DNA damage in Caenorhabditis elegans

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

Hartman, P.S.; Hevelone, J.; Dwarakanath, V.

1989-06-01

Radioimmunoassays were used to monitor the removal of antibody-binding sites associated with the two major UV radiation-induced DNA photoproducts (cyclobutane dimers and (6-4) photoproducts). Unlike with cultured human cells, where (6-4) photoproducts are removed more rapidly than cyclobutane dimers, the kinetics of repair were similar for both lesions. Repair capacity in wild type diminished throughout development. The radioimmunoassays were also employed to confirm the absence of photoreactivation in C. elegans. In addition, three radiation-sensitive mutants (rad-1, rad-2, rad-7) displayed normal repair capacities. An excision defect was much more pronounced in larvae than embryos in the fourth mutant tested (rad-3). Thismore » correlates with the hypersensitivity pattern of this mutant and suggests that DNA repair may be developmentally regulated in C. elegans. The mechanism of DNA repair in C. elegans as well as the relationship between the repair of specific photoproducts and UV radiation sensitivity during development are discussed.« less

Effect of different concentration of HPV DNA probe immobilization for cervical cancer detection based IDE biosensor

NASA Astrophysics Data System (ADS)

Roshila, M. L.; Hashim, U.; Azizah, N.; Nadzirah, Sh.; Arshad, M. K. Md; Ruslinda, A. R.; Gopinath, Subash C. B.

2017-03-01

This paper principally delineates to the detection process of Human Papillomavirus (HPV) DNA test. HPV is an extremely common virus infection that infected to human by the progressions cell in the cervix cell. The types of HPV that give a most exceedingly awful infected with cervical cancer is 16 and 18 other than 31 and 45. The HPV DNA probe is immobilized with a different concentration to stabilize the sensitivity. A technique of rapid and sensitive for the HPV identification was proposed by coordinating basic DNA extraction with a quality of DNA. The extraction of the quality of DNA will make a proficiency of the discovery procedure. It will rely on the sequence of the capture probes and the way to support their attached. The fabrication, surface modification, immobilization and hybridization procedures are described by current-voltage (I-V) estimation by utilizing KEITHLEY 6487. This procedure will play out a decent affectability and selectivity of HPV discovery.

Fabrication of Lab-on-Paper Using Porous Au-Paper Electrode: Application to Tumor Marker Electrochemical Immunoassays.

PubMed

Ge, Shenguang; Zhang, Yan; Yan, Mei; Huang, Jiadong; Yu, Jinghua

2017-01-01

A simple, low-cost, and sensitive electrochemical lab-on-paper assay is developed based on a novel gold nanoparticle modified porous paper working electrode for use in point-of-care testing (POCT). Electrochemical methods are introduced for lab-on-paper based on screen-printed paper electrodes. To further improve specificity, performance, and sensitivity for point-of-care testing, a novel porous Au-paper working electrode (Au-PWE) is designed for lab-on-paper using growth of an interconnected Au nanoparticle (NP) layer on the surface of cellulose fibers in order to enhance the conductivity of the paper sample zone and immobilize the primary antibodies (Ab1). With a sandwich-type immunoassay format, Pd-Au bimetallic nanoparticles possessing peroxidase-like activity are used as a matrix to immobilize secondary antibodies (Ab2) for rapid detection of targets. This lab-on-paper based immunodevice is applied to the diagnosis of a cancer biomarker in clinical serum samples.

Development of a multiplex probe combination-based one-step real-time reverse transcription-PCR for NA subtype typing of avian influenza virus.

PubMed

Sun, Zhihao; Qin, Tao; Meng, Feifei; Chen, Sujuan; Peng, Daxin; Liu, Xiufan

2017-10-18

Nine influenza virus neuraminidase (NA) subtypes have been identified in poultry and wild birds. Few methods are available for rapid and simple NA subtyping. Here we developed a multiplex probe combination-based one-step real-time reverse transcriptase PCR (rRT-PCR) to detect nine avian influenza virus NA subtypes. Nine primer-probe pairs were assigned to three groups based on the different fluorescent dyes of the probes (FAM, HEX, or Texas Red). Each probe detected only one NA subtype, without cross reactivity. The detection limit was less than 100 EID 50 or 100 copies of cDNA per reaction. Data obtained using this method with allantoic fluid samples isolated from live bird markets and H9N2-infected chickens correlated well with data obtained using virus isolation and sequencing, but was more sensitive. This new method provides a specific and sensitive alternative to conventional NA-subtyping methods.

Simulated weightlessness in fish and neurophysiological studies on memory storage

NASA Technical Reports Server (NTRS)

Vonbaumgarten, R. J.

1973-01-01

Simulated weightlessness was used to study the different types of gravity responses in blind fish. It was found that a shift in the direction of low magnitude acceleration in weightlessness causes a rapid 180 deg turn in the blind fish, while a shift in the direction of the applied acceleration in the earth's gravitational field is not significant because of a higher acceleration magnitude threshold than during the zero g condition. This increased responsiveness seems to be explained by a combination of directional sensitivity with a Weber-Fechner relationship of increased receptor sensitivity at diminished levels of background stimulation. Neurophysical studies of the statocyst nerve of the gastropod Mollusc Pleurobranchaea Californica were undertaken in order to understand how complex otolith systems operate. Information storage was investigated on relatively simple neuronal networks in the mollusc Aplysia. Intracellular electrical stimulation of isolated neurons show that a manipulation of autoditonous rhymicity is possible. It was also found that glycolysis and oxidative phosphorylation are involved in inherent rhymicity of Aplysis neurons.

Near-term hybrid vehicle program, phase 1. Appendix D: Sensitivity analysis resport

NASA Technical Reports Server (NTRS)

1979-01-01

Parametric analyses, using a hybrid vehicle synthesis and economics program (HYVELD) are described investigating the sensitivity of hybrid vehicle cost, fuel usage, utility, and marketability to changes in travel statistics, energy costs, vehicle lifetime and maintenance, owner use patterns, internal combustion engine (ICE) reference vehicle fuel economy, and drive-line component costs and type. The lowest initial cost of the hybrid vehicle would be $1200 to $1500 higher than that of the conventional vehicle. For nominal energy costs ($1.00/gal for gasoline and 4.2 cents/kWh for electricity), the ownership cost of the hybrid vehicle is projected to be 0.5 to 1.0 cents/mi less than the conventional ICE vehicle. To attain this ownership cost differential, the lifetime of the hybrid vehicle must be extended to 12 years and its maintenance cost reduced by 25 percent compared with the conventional vehicle. The ownership cost advantage of the hybrid vehicle increases rapidly as the price of fuel increases from $1 to $2/gal.

Mechanisms of chronic pain - key considerations for appropriate physical therapy management.

PubMed

Courtney, Carol A; Fernández-de-Las-Peñas, César; Bond, Samantha

2017-07-01

In last decades, knowledge of nociceptive pain mechanisms has expanded rapidly. The use of quantitative sensory testing has provided evidence that peripheral and central sensitization mechanisms play a relevant role in localized and widespread chronic pain syndromes. In fact, almost any patient suffering with a chronic pain condition will demonstrate impairments in the central nervous system. In addition, it is accepted that pain is associated with different types of trigger factors including social, physiological, and psychological. This rational has provoked a change in the understanding of potential mechanisms of manual therapies, changing from a biomechanical/medical viewpoint, to a neurophysiological/nociceptive viewpoint. Therefore, interventions for patients with chronic pain should be applied based on current knowledge of nociceptive mechanisms since determining potential drivers of the sensitization process is critical for effective management. The current paper reviews mechanisms of chronic pain from a clinical and neurophysiological point of view and summarizes key messages for clinicians for proper management of individuals with chronic pain.

Simultaneous Determination of Isopyrazam and Azoxystrobin in Cucumbers by Liquid Chromatography-Tandem Mass Spectrometry.

PubMed

Hu, Dan; Xu, Xu; Cai, Tian; Wang, Wei-Ying; Wu, Chun-Jie; Ye, Li-Ming

2017-12-01

A rapid and sensitive analytical method based on high-performance liquid chromatography-tandem mass spectrometry was developed and validated for the determination of isopyrazam (IZM) and azoxystrobin (AZT) in cucumbers. A modified QuEChERS (quick, easy, cheap, effective, rugged, and safe) method was used as the pretreatment procedure. The samples were extracted with acetonitrile and cleaned up with octadecylsilyl silica (C18) and graphite carbon black. The proposed method resulted in satisfactory recovery of IZM and AZT (91.48 to 114.62%), and relative standard deviations were less than 13.1% at fortification concentrations of 1, 20, and 500 μg kg -1 (n = 3). The limits of quantification for IZM and AZT were 0.498 and 0.499 μg kg -1 , respectively, which are far below the maximum residue level (0.5 mg kg -1 ) established for this type of sample. Matrix effects were also evaluated. This study established a sensitive and fast method for the detection of IZM and AZT in cucumber samples.

Sensitive clay landslide detection and characterization in and around Lakelse Lake, British Columbia, Canada

NASA Astrophysics Data System (ADS)

Geertsema, Marten; Blais-Stevens, Andrée; Kwoll, Eva; Menounos, Brian; Venditti, Jeremy G.; Grenier, Alain; Wiebe, Kelsey

2018-02-01

The Lakelse Lake area in northwestern British Columbia, Canada, has a long history, and prehistory, of rapid sensitive clay landslides moving on very low gradients. However, until now, many landslides have gone undetected. We use an array of modern tools to identify hitherto unknown or poorly known landslide deposits, including acoustic subbottom profiles, multibeam sonar, and LiDAR. The combination of these methods reveals not only landslide deposits, but also geomorphic and sedimentologic structures that give clues about landslide type and mode of emplacement. LiDAR and bathymetric data reveal the areal extent of landslide deposits as well as the orientation of ridges that differentiate between spreading and flowing kinematics. The subbottom profiles show two-dimensional structures of disturbed landslide deposits, including horst and grabens indicative of landslides classified as spreads. A preliminary computer tomography (CT) scan of a sediment core confirms the structures of one subbottom profile. We also use archival data from the Ministry of Transportation and Infrastructure and resident interviews to better characterize historic landslides.

Detection of viral infection and gene expression in clinical tissue specimens using branched DNA (bDNA) in situ hybridization.

PubMed

Kenny, Daryn; Shen, Lu-Ping; Kolberg, Janice A

2002-09-01

In situ hybridization (ISH) methods for detection of nucleic acid sequences have proved especially powerful for revealing genetic markers and gene expression in a morphological context. Although target and signal amplification technologies have enabled researchers to detect relatively low-abundance molecules in cell extracts, the sensitive detection of nucleic acid sequences in tissue specimens has proved more challenging. We recently reported the development of a branched DNA (bDNA) ISH method for detection of DNA and mRNA in whole cells. Based on bDNA signal amplification technology, bDNA ISH is highly sensitive and can detect one or two copies of DNA per cell. In this study we evaluated bDNA ISH for detection of nucleic acid sequences in tissue specimens. Using normal and human papillomavirus (HPV)-infected cervical biopsy specimens, we explored the cell type-specific distribution of HPV DNA and mRNA by bDNA ISH. We found that bDNA ISH allowed rapid, sensitive detection of nucleic acids with high specificity while preserving tissue morphology. As an adjunct to conventional histopathology, bDNA ISH may improve diagnostic accuracy and prognosis for viral and neoplastic diseases.

Meta-analysis for the comparison of two diagnostic tests to a common gold standard: A generalized linear mixed model approach.

PubMed

Hoyer, Annika; Kuss, Oliver

2018-05-01

Meta-analysis of diagnostic studies is still a rapidly developing area of biostatistical research. Especially, there is an increasing interest in methods to compare different diagnostic tests to a common gold standard. Restricting to the case of two diagnostic tests, in these meta-analyses the parameters of interest are the differences of sensitivities and specificities (with their corresponding confidence intervals) between the two diagnostic tests while accounting for the various associations across single studies and between the two tests. We propose statistical models with a quadrivariate response (where sensitivity of test 1, specificity of test 1, sensitivity of test 2, and specificity of test 2 are the four responses) as a sensible approach to this task. Using a quadrivariate generalized linear mixed model naturally generalizes the common standard bivariate model of meta-analysis for a single diagnostic test. If information on several thresholds of the tests is available, the quadrivariate model can be further generalized to yield a comparison of full receiver operating characteristic (ROC) curves. We illustrate our model by an example where two screening methods for the diagnosis of type 2 diabetes are compared.

Coupling photochemical reaction detection based on singlet oxygen sensitization to capillary electrochromatography

PubMed

Dickson; Odom; Ducheneaux; Murray; Milofsky

2000-07-15

Despite the impressive separation efficiency afforded by capillary electrochromatography (CEC), the detection of UV-absorbing compounds following separation in capillary dimensions remains limited by the short path length (5-75 microm) through the column. Moreover, analytes that are poor chromophores present an additional challenge with respect to sensitive detection in CEC. This paper illustrates a new photochemical reaction detection scheme for CEC that takes advantage of the catalytic nature of type II photooxidation reactions. The sensitive detection scheme is selective toward molecules capable of photosensitizing the formation of singlet molecular oxygen (1O2). Following separation by CEC, UV-absorbing analytes promote groundstate 3O2 to an excited state (1O2) which reacts rapidly with tert-butyl-3,4,5-trimethylpyrrolecarboxylate, which is added to the running buffer. Detection is based on the loss of pyrrole. The reaction is catalytic in nature since one analyte molecule may absorb light many times, producing large amounts of 1O2. The detection limit for 9-acetylanthracene, following separation by CEC, is approximately 6 x 10(-9) M (S/N = 3). Optimization of the factors effecting the S/N for four model compounds is discussed.

STUDIES ON TUBERCULIN FEVER

PubMed Central

Hall, Charles H.; Atkins, Elisha

1959-01-01

Evidence has been presented that the fever elicited by intravenous administration of old tuberculin (O.T.) in BCG-infected rabbits is a specific property of this hypersensitivity system and is probably not due to contamination of tuberculin with bacterial endotoxins. Daily injections of O.T. in sensitized animals resulted in a rapid tolerance to its pyrogenic effect. Tuberculin tolerance can be differentiated from that occurring with endotoxins and was invariably associated with the development of a negative skin test. The mechanism of this tolerance would thus appear to be desensitization. A circulating pyrogen found during tuberculin fever was indistinguishable in its biologic effects from endogenous pyrogens obtained in several other types of experimental fever. This material produced fevers in normal recipients and therefore may be clearly differentiated from O.T. itself which was pyrogenic only to sensitized animals. Since the titer of serum pyrogen was directly proportional to the degree of fever induced by injection of O.T. in the donor animals, a causal relation is suggested. On the basis of these findings, it is postulated that tuberculin fever is due to a circulating endogenous pyrogen released by a specific action of O.T. on sensitized cells of the host. PMID:13641561

Riems influenza a typing array (RITA): An RT-qPCR-based low density array for subtyping avian and mammalian influenza a viruses.

PubMed

Hoffmann, Bernd; Hoffmann, Donata; Henritzi, Dinah; Beer, Martin; Harder, Timm C

2016-06-03

Rapid and sensitive diagnostic approaches are of the utmost importance for the detection of humans and animals infected by specific influenza virus subtype(s). Cascade-like diagnostics starting with the use of pan-influenza assays and subsequent subtyping devices are normally used. Here, we demonstrated a novel low density array combining 32 TaqMan(®) real-time RT-PCR systems in parallel for the specific detection of the haemagglutinin (HA) and neuraminidase (NA) subtypes of avian and porcine hosts. The sensitivity of the newly developed system was compared with that of the pan-influenza assay, and the specificity of all RT-qPCRs was examined using a broad panel of 404 different influenza A virus isolates representing 45 different subtypes. Furthermore, we analysed the performance of the RT-qPCR assays with diagnostic samples obtained from wild birds and swine. Due to the open format of the array, adaptations to detect newly emerging influenza A virus strains can easily be integrated. The RITA array represents a competitive, fast and sensitive subtyping tool that requires neither new machinery nor additional training of staff in a lab where RT-qPCR is already established.

Comparative proteomic analysis using samples obtained with laser microdissection and saturation dye labelling.

PubMed

Wilson, Kate E; Marouga, Rita; Prime, John E; Pashby, D Paul; Orange, Paul R; Crosier, Steven; Keith, Alexander B; Lathe, Richard; Mullins, John; Estibeiro, Peter; Bergling, Helene; Hawkins, Edward; Morris, Christopher M

2005-10-01

Comparative proteomic methods are rapidly being applied to many different biological systems including complex tissues. One pitfall of these methods is that in some cases, such as oncology and neuroscience, tissue complexity requires isolation of specific cell types and sample is limited. Laser microdissection (LMD) is commonly used for obtaining such samples for proteomic studies. We have combined LMD with sensitive thiol-reactive saturation dye labelling of protein samples and 2-D DIGE to identify protein changes in a test system, the isolated CA1 pyramidal neurone layer of a transgenic (Tg) rat carrying a human amyloid precursor protein transgene. Saturation dye labelling proved to be extremely sensitive with a spot map of over 5,000 proteins being readily produced from 5 mug total protein, with over 100 proteins being significantly altered at p < 0.0005. Of the proteins identified, all showed coherent changes associated with transgene expression. It was, however, difficult to identify significantly different proteins using PMF and MALDI-TOF on gels containing less than 500 mug total protein. The use of saturation dye labelling of limiting samples will therefore require the use of highly sensitive MS techniques to identify the significantly altered proteins isolated using methods such as LMD.

Quantification of α-tubulin isotypes by sandwich ELISA with signal amplification through biotinyl-tyramide or immuno-PCR.

PubMed

Dráberová, Eduarda; Stegurová, Lucie; Sulimenko, Vadym; Hájková, Zuzana; Dráber, Petr; Dráber, Pavel

2013-09-30

Microtubules formed by αβ-tubulin dimers represent cellular structures that are indispensable for the maintenance of cell morphology and for cell motility generation. Microtubules in intact cells are in highly regulated equilibrium with cellular pools of soluble tubulin dimers. Sensitive, reproducible and rapid assays are necessary to monitor tubulin changes in cytosolic pools after treatment with anti-mitotic drugs, during the cell cycle or activation and differentiation events. Here we describe new assays for α-tubulin quantification. The assays are based on sandwich ELISA, and the signal is amplified with biotinyl-tyramide or immuno-PCR. Matching monoclonal antibody pair recognizes phylogenetically highly conserved epitopes localized outside the C-terminal isotype-defining region. This makes it possible to detect α-tubulin isotypes in different cell types of various species. Biotinyl-tyramide amplification and immuno-PCR amplification enable detection of tubulin at concentrations 2.5ng/ml and 0.086ng/ml, respectively. Immuno-PCR detection shows enhanced sensitivity and wider dynamic range when compared to ELISA with biotinyl-tyramide detection. Our results on taxol-treated and activated bone marrow-derived mast cells demonstrate, that the assays allow sensitive quantification of tubulin in complex biological fluids. © 2013.

The chemiluminescent response of human monocytes to red cells sensitized with monoclonal anti-Rh(D) antibodies.

PubMed

Hadley, A G; Kumpel, B M; Merry, A H

1988-01-01

Luminol-enhanced chemiluminescence (CL) was used to assess the metabolic response of human monocytes to red cells sensitized with known amounts of anti-Rh(D). Monoclonal antibodies were used to facilitate a comparison between the functional activities of IgG1 and IgG3 subclasses. The detection of CL provided a simple, rapid and semi-quantitative means of measuring monocyte response to sensitized red cells (IgG-RBC). Monocyte response to IgG3-RBC was quantitatively greater, more rapid and less susceptible to inhibition by fluid phase IgG than monocyte response to IgG1-RBC. The minimum levels of sensitization required to elicit CL from monocytes were approximately 2500 IgG3 molecules per red cell, or approximately 5000 IgG1 molecules per cell.

Predictive abilities of cardiovascular biomarkers to rapid decline of renal function in Chinese community-dwelling population: a 5-year prospective analysis.

PubMed

Fu, Shihui; Liu, Chunling; Luo, Leiming; Ye, Ping

2017-11-09

Predictive abilities of cardiovascular biomarkers to renal function decline are more significant in Chinese community-dwelling population without glomerular filtration rate (GFR) below 60 ml/min/1.73m 2 , and long-term prospective study is an optimal choice to explore this problem. Aim of this analysis was to observe this problem during the follow-up of 5 years. In a large medical check-up program in Beijing, there were 948 participants with renal function evaluated at baseline and follow-up of 5 years. Physical examinations were performed by well-trained physicians. Blood samples were analyzed by qualified technicians in central laboratory. Median rate of renal function decline was 1.46 (0.42-2.91) mL/min/1.73m 2 /year. Rapid decline of renal function had a prevalence of 23.5% (223 participants). Multivariate linear and Logistic regression analyses confirmed that age, sex, baseline GFR, homocysteine and N-terminal pro B-type natriuretic peptide (NT-proBNP) had independently predictive abilities to renal function decline rate and rapid decline of renal function (p < 0.05 for all). High-sensitivity cardiac troponin T (hs-cTnT), carotid femoral pulse wave velocity and central augmentation index had no statistically independent association with renal function decline rate and rapid decline of renal function (p > 0.05 for all). Homocysteine and NT-proBNP rather than hs-cTnT had independently predictive abilities to rapid decline of renal function in Chinese community-dwelling population without GFR below 60 ml/min/1.73m 2 . Baseline GFR was an independent factor predicting the rapid decline of renal function. Arterial stiffness and compliance had no independent effect on rapid decline of renal function. This analysis has a significant implication for public health, and changing the homocysteine and NT-proBNP levels might slow the rapid decline of renal function.

Effects of glutamate, substance P and eledoisin-related peptide on solitary tract neurones involved in respiration and respiratory reflexes.

PubMed

Henry, J L; Sessle, B J

1985-03-01

Recent studies have implicated glutamate and substance P in synaptic transmission in the nuclei tractus solitarii and in central regulation of cardiorespiratory functions. Consequently, in chloralose-anaesthetized cats that were artificially ventilated, we examined the effects of the microiontophoretic application of both chemicals (and the substance P homologue, eledoisin-related peptide) on single neurones of the nuclei tractus solitarii implicated in the control of respiration and respiratory tract reflexes. These neurones were functionally identified as either respiratory neurones or presumed reflex interneurones, and showed functional properties comparable to those previously documented for each of these two types. The iontophoretic application of glutamate produced an excitation of rapid onset in 23 or 25 reflex interneurones tested, but the respiratory neurones showed a differential sensitivity: one type (n = 32) was "glutamate-sensitive" and showed rapid excitation with glutamate applications of less than 30 nA, the other type of respiratory neurone (n = 26) was termed "glutamate-insensitive" since it either showed excitation only with applications of 60 nA or more or showed no response even with currents up to 94 nA. Each neurone studied was clearly of one type or the other. Glutamate could increase the number of spikes per rhythmic burst and the burst duration of respiratory neurones, it facilitated evoked activity in the reflex interneurones and in those respiratory neurones having a superior laryngeal nerve or vagus nerve afferent input, and the magnitude of the excitatory responses to glutamate varied directly with the amount of ejecting current. Substance P and eledoisin-related peptide also had excitatory effects on respiratory neurones and reflex interneurones, but compared with glutamate-induced effects the excitation was slower in onset and more prolonged in after-discharge. Both rhythmic and evoked activity could be facilitated, and the magnitude of the effect varied directly with the magnitude of the ejecting current. In showing that both glutamate and substance P (and its analogue, eledoisin-related peptide) have excitatory effects on the activity of respiratory neurones and reflex interneurones, this study provides evidence suggesting that these neurones have receptors for these neural chemicals, supportive of a role for each chemical in the regulation of respiration and respiratory tract reflexes.

Assessing direct analysis in real-time-mass spectrometry (DART-MS) for the rapid identification of additives in food packaging.

PubMed

Ackerman, L K; Noonan, G O; Begley, T H

2009-12-01

The ambient ionization technique direct analysis in real time (DART) was characterized and evaluated for the screening of food packaging for the presence of packaging additives using a benchtop mass spectrometer (MS). Approximate optimum conditions were determined for 13 common food-packaging additives, including plasticizers, anti-oxidants, colorants, grease-proofers, and ultraviolet light stabilizers. Method sensitivity and linearity were evaluated using solutions and characterized polymer samples. Additionally, the response of a model additive (di-ethyl-hexyl-phthalate) was examined across a range of sample positions, DART, and MS conditions (temperature, voltage and helium flow). Under optimal conditions, molecular ion (M+H+) was the major ion for most additives. Additive responses were highly sensitive to sample and DART source orientation, as well as to DART flow rates, temperatures, and MS inlet voltages, respectively. DART-MS response was neither consistently linear nor quantitative in this setting, and sensitivity varied by additive. All additives studied were rapidly identified in multiple food-packaging materials by DART-MS/MS, suggesting this technique can be used to screen food packaging rapidly. However, method sensitivity and quantitation requires further study and improvement.

Gold Nanoparticles as a Direct and Rapid Sensor for Sensitive Analytical Detection of Biogenic Amines

NASA Astrophysics Data System (ADS)

El-Nour, K. M. A.; Salam, E. T. A.; Soliman, H. M.; Orabi, A. S.

2017-03-01

A new optical sensor was developed for rapid screening with high sensitivity for the existence of biogenic amines (BAs) in poultry meat samples. Gold nanoparticles (GNPs) with particle size 11-19 nm function as a fast and sensitive biosensor for detection of histamine resulting from bacterial decarboxylation of histidine as a spoilage marker for stored poultry meat. Upon reaction with histamine, the red color of the GNPs converted into deep blue. The appearance of blue color favorably coincides with the concentration of BAs that can induce symptoms of poisoning. This biosensor enables a semi-quantitative detection of analyte in real samples by eye-vision. Quality evaluation is carried out by measuring histamine and histidine using different analytical techniques such as UV-vis, FTIR, and fluorescence spectroscopy as well as TEM. A rapid quantitative readout of samples by UV-vis and fluorescence methods with standard instrumentation were proposed in a short time unlike chromatographic and electrophoretic methods. Sensitivity and limit of detection (LOD) of 6.59 × 10-4 and 0.6 μM, respectively, are determined for histamine as a spoilage marker with a correlation coefficient ( R 2) of 0.993.

Synthesis of molecularly imprinted dye-silica nanocomposites with high selectivity and sensitivity: Fluorescent imprinted sensor for rapid and efficient detection of τ-fluvalinate in vodka.

PubMed

Wang, Yunyun; Wang, Jixiang; Cheng, Rujia; Sun, Lin; Dai, Xiaohui; Yan, Yongsheng

2018-04-01

An imprinted fluorescent sensor was fabricated based on SiO 2 nanoparticles encapsulated with a molecularly imprinted polymer containing allyl fluorescein. High fluorine cypermethirin as template molecules, methyl methacrylate as functional monomer, and allyl fluorescein as optical materials synthesized a core-shell fluorescent molecular imprinted sensor, which showed a high and rapid sensitivity and selectivity for the detection of τ-fluvalinate. The sensor presented appreciable sensitivity with a limit of 13.251 nM, rapid detection that reached to equilibrium within 3 min, great linear relationship in the relevant concentration range from 0 to 150 nM, and excellent selectivity over structural analogues. In addition, the fluorescent sensor demonstrated desirable regeneration ability (eight cycling operations). The molecularly imprinted polymers ensured specificity, while the fluorescent dyes provided the stabile sensitivity. Finally, an effective application of the sensor was implemented by the detection of τ-fluvalinate in real samples from vodka. The molecularly imprinted fluorescent sensor showed a promising potential in environmental monitoring and food safety. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Application of loop-mediated isothermal amplification assay for the sensitive and rapid diagnosis of visceral leishmaniasis and post-kala-azar dermal leishmaniasis.

PubMed

Verma, Sandeep; Avishek, Kumar; Sharma, Vanila; Negi, Narendra Singh; Ramesh, Venkatesh; Salotra, Poonam

2013-04-01

Loop-mediated isothermal amplification (LAMP) is at the forefront in the search for innovative diagnostics for rapid and specific amplification of target DNA under isothermal conditions. We have applied LAMP assay using SYBR Green for clear-cut naked eye detection of Leishmania (Leishmania) donovani in 200 clinical samples of visceral leishmaniasis (VL) and post-kala-azar dermal leishmaniasis (PKDL). The assay was positive in 53/55 VL blood samples (sensitivity, 96.4%; 95% confidence interval [CI], 87.7-99%), 15/15 VL bone marrow aspirate samples (sensitivity, 100%; 95% CI, 79.6-100%), 60/62 PKDL tissue biopsy samples (sensitivity, 96.8%; 95% CI, 88.9-99.1%), and 1/68 control samples (specificity, 98.5%; 95% CI, 92.1-99.7%). The assay was specific for L. (L.) donovani, the causative species for VL and negative for L. (L.) infantum, L. (L.) tropica, and L. (L.) major. This is the first comprehensive clinical study demonstrating the applicability of the LAMP assay for a rapid and reliable molecular diagnosis of VL and PKDL. Copyright © 2013 Elsevier Inc. All rights reserved.

Uncomplicated malaria in children: The place of rapid diagnostic test.

PubMed

Elechi, Hassan Abdullahi; Rabasa, Adamu Ibrahim; Bashir, Muhammad Faruk; Gofama, Mustapha Modu; Ibrahim, Halima Abubakar; Askira, Umoru Muhammed

2015-01-01

Malaria has remained a major cause of morbidity and mortality among the under-five children in Nigeria. Prompt and accurate diagnosis of malaria is necessary in controlling this high burden and preventing unnecessary use of anti-malarial drugs. Malaria rapid diagnostic test (MRDT) offers the hope of achieving this goal. However, the performance of these kits among the most vulnerable age group to malaria is inadequate. In this cross-sectional study, 433 out-patients, aged <5 years with fever or history of fever were enrolled. Each candidate was tested for malaria parasitaemia using ACON; malaria pf. Thick and thin films were also prepared from the same finger prick blood for each candidate. Malaria rapid diagnostic test had sensitivity of 8.3%, specificity of 100%, positive predictive value (PPV) of 100% and negative predictive value (NPV) of 74%. The sensitivity of MRDT increased with increasing age. This effect of age on sensitivity was statistically significant (P = 0.007). Similarly parasite density had significant effect on the sensitivity of MRDT (P = <0.001). Histidine-rich protein-2 based MRDT is not a reliable mean of diagnosing malaria in the under-five age children with acute uncomplicated malaria.

Contributions of two types of calcium channels to synaptic transmission and plasticity.

PubMed

Edmonds, B; Klein, M; Dale, N; Kandel, E R

1990-11-23

In Aplysia sensory and motor neurons in culture, the contributions of the major classes of calcium current can be selectively examined while transmitter release and its modulation are examined. A slowly inactivating, dihydropyridine-sensitive calcium current does not contribute either to normal synaptic transmission or to any of three different forms of plasticity: presynaptic inhibition, homosynaptic depression, and presynaptic facilitation. This current does contribute, however, to a fourth form of plasticity--modulation of transmitter release by tonic depolarization of the sensory neuron. By contrast, a second calcium current, which is rapidly inactivating and dihydropyridine-insensitive, contributes to release elicited by the transient depolarization of an action potential and to the other three forms of plasticity.

Rapid, Sensitive Detection of Botulinum Toxin on a Flexible Microfluidics Platform

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

Warner, Marvin G.; Dockendorff, Brian P.; Feldhaus, Michael J.

2004-10-30

In this paper we will describe how high affinity reagents and a sensor configuration enabling rapid mass transport can be combined for rapid, sensitive biodetection. The system that we have developed includes a renewable surface immunoassay, which involves on-column detection of a fluorescently labeled secondary antibody in a sandwich immunoassay. Yeast display and directed molecular evolution were used to create high affinity antibodies to the botulinum toxin heavy chain receptor binding domain, AR1 and 3D12. A rotating rod renewable surface microcolumn was used to form a microliter-sized column containing beads functionalized with the capture antibody (AR1). The column was perfusedmore » with sample, wash solutions, and a fluorescently labeled secondary antibody (3D12) while the on-column fluorescence was monitored. Detection was accomplished in less than 5 minutes, with a total processing time of about 10 minutes. On-column detection of botulinum toxin was more sensitive and much faster than flow cytometry analysis on microbeads using the same reagents.« less

Lung vagal afferent activity in rats with bleomycin-induced lung fibrosis.

PubMed

Schelegle, E S; Walby, W F; Mansoor, J K; Chen, A T

2001-05-01

Bleomycin treatment in rats results in pulmonary fibrosis that is characterized by a rapid shallow breathing pattern, a decrease in quasi-static lung compliance and a blunting of the Hering-Breuer Inflation Reflex. We examined the impulse activity of pulmonary vagal afferents in anesthetized, mechanically ventilated rats with bleomycin-induced lung fibrosis during the ventilator cycle and static lung inflations/deflations and following the injection of capsaicin into the right atrium. Bleomycin enhanced volume sensitivity of slowly adapting stretch receptors (SARs), while it blunted the sensitivity of these receptors to increasing transpulmonary pressure. Bleomycin treatment increased the inspiratory activity, while it decreased the expiratory activity of rapidly adapting stretch receptors (RARs). Pulmonary C-fiber impulse activity did not appear to be affected by bleomycin treatment. We conclude that the fibrosis-related shift in discharge profile and enhanced volume sensitivity of SARs combined with the increased inspiratory activity of RARs contributes to the observed rapid shallow breathing of bleomycin-induced lung fibrosis.

Aptamer-Nanoparticle Strip Biosensor for Rapid and Sensitive Detection of Cancer Cells

PubMed Central

Mao, Xun; Phillips, Joseph A.; Xu, Hui; Tan, Weihong; Zeng, Lingwen; Liu, Guodong

2009-01-01

We report an aptamer-nanoparticle strip biosensor (ANSB) for the rapid, specific, sensitive and low-cost detection of circulating cancer cells. Known for their high specificity and affinity, aptamers were first selected from live cells by the cell-SELEX (systematic evolution of ligands by exponential enrichment) process. When next combined with the unique optical properties of gold nanoparticles (Au-NPs), ANSBs were prepared on a lateral flow device. Ramos cells were used as a model target cell to demonstrate proof of principle. Under optimal conditions, the ANSB was capable of detecting a minimum of 4000 Ramos cells without instrumentation (visual judgment) and 800 Ramos cells with a portable strip reader within 15 minutes. Importantly, ANSB has successfully detected Ramos cells in human blood, thus providing a rapid, sensitive and low-cost quantitative tool for the detection of circulating cancer cells. ANSB therefore shows great promise for in-field and point-of-care cancer diagnosis and therapy. PMID:19904989

Biotunable Nanoplasmonic Filter on Few-Layer MoS2 for Rapid and Highly Sensitive Cytokine Optoelectronic Immunosensing.

PubMed

Park, Younggeun; Ryu, Byunghoon; Oh, Bo-Ram; Song, Yujing; Liang, Xiaogan; Kurabayashi, Katsuo

2017-06-27

Monitoring of the time-varying immune status of a diseased host often requires rapid and sensitive detection of cytokines. Metallic nanoparticle-based localized surface plasmon resonance (LSPR) biosensors hold promise to meet this clinical need by permitting label-free detection of target biomolecules. These biosensors, however, continue to suffer from relatively low sensitivity as compared to conventional immunoassay methods that involve labeling processes. Their response speeds also need to be further improved to enable rapid cytokine quantification for critical care in a timely manner. In this paper, we report an immunobiosensing device integrating a biotunable nanoplasmonic optical filter and a highly sensitive few-layer molybdenum disulfide (MoS 2 ) photoconductive component, which can serve as a generic device platform to meet the need of rapid cytokine detection with high sensitivity. The nanoplasmonic filter consists of anticytokine antibody-conjugated gold nanoparticles on a SiO 2 thin layer that is placed 170 μm above a few-layer MoS 2 photoconductive flake device. The principle of the biosensor operation is based on tuning the delivery of incident light to the few-layer MoS 2 photoconductive flake thorough the nanoplasmonic filter by means of biomolecular surface binding-induced LSPR shifts. The tuning is dependent on cytokine concentration on the nanoplasmonic filter and optoelectronically detected by the few-layer MoS 2 device. Using the developed optoelectronic biosensor, we have demonstrated label-free detection of IL-1β, a pro-inflammatory cytokine, with a detection limit as low as 250 fg/mL (14 fM), a large dynamic range of 10 6 , and a short assay time of 10 min. The presented biosensing approach could be further developed and generalized for point-of-care diagnosis, wearable bio/chemical sensing, and environmental monitoring.

Field-based performance of three pre-market rapid hepatitis C virus antibody assays in STAHR (Study to Assess Hepatitis C Risk) among young adults who inject drugs in San Diego, CA.

PubMed

Jewett, A; Smith, B D; Garfein, R S; Cuevas-Mota, J; Teshale, E H; Weinbaum, C M

2012-07-01

Approximately 4.1 million Americans are estimated to have been infected with hepatitis C virus (HCV), 45-85% of whom are unaware of their infection. Persons who inject drugs (PWID) account for 55.8% of all persons with HCV antibody (anti-HCV) in the U.S. PWID have limited access to healthcare and are infrequently tested for anti-HCV using conventional laboratory assays. To evaluate performance characteristics (sensitivity and specificity) of three, pre-market rapid point-of-care tests (one oral fluid and two finger-stick assays) from two manufacturers (Chembio and MedMira) in settings providing services to young adult PWID in San Diego, CA. Behavioral risk assessment surveys and testing for HCV were conducted among persons who reported injection drug use (IDU) within the past 6 months as part of the Study to Assess Hepatitis C Risk (STAHR) among PWID aged 18-40 years in 2009-2010. Sensitivity and specificity of the rapid anti-HCV assays were evaluated among STAHR participants, using two commonly used testing algorithms. Variability in sensitivity (76.6-97.1%) and specificity (99.0-100.0%) was found across assays. The highest sensitivity achieved for the Chembio finger-stick blood, Chembio oral fluid and MedMira finger-stick blood tests was 97.1%, 85.4% and 80.0% respectively; the highest specificity was 99.0%, 100.0% and 100.0%, respectively. In multivariate analysis false negative anti-HCV results were associated with female sex for the MedMira blood assay. Sensitive anti-HCV rapid assays are appropriate and feasible for high-prevalence, high-risk populations such as young PWID. Copyright © 2012 Elsevier B.V. All rights reserved.

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.

Bacteriophage Amplification-Coupled Detection and Identification of Bacterial Pathogens

NASA Astrophysics Data System (ADS)

Cox, Christopher R.; Voorhees, Kent J.

Current methods of species-specific bacterial detection and identification are complex, time-consuming, and often require expensive specialized equipment and highly trained personnel. Numerous biochemical and genotypic identification methods have been applied to bacterial characterization, but all rely on tedious microbiological culturing practices and/or costly sequencing protocols which render them impractical for deployment as rapid, cost-effective point-of-care or field detection and identification methods. With a view towards addressing these shortcomings, we have exploited the evolutionarily conserved interactions between a bacteriophage (phage) and its bacterial host to develop species-specific detection methods. Phage amplification-coupled matrix assisted laser desorption time-of-flight mass spectrometry (MALDI-TOF-MS) was utilized to rapidly detect phage propagation resulting from species-specific in vitro bacterial infection. This novel signal amplification method allowed for bacterial detection and identification in as little as 2 h, and when combined with disulfide bond reduction methods developed in our laboratory to enhance MALDI-TOF-MS resolution, was observed to lower the limit of detection by several orders of magnitude over conventional spectroscopy and phage typing methods. Phage amplification has been combined with lateral flow immunochromatography (LFI) to develop rapid, easy-to-operate, portable, species-specific point-of-care (POC) detection devices. Prototype LFI detectors have been developed and characterized for Yersinia pestis and Bacillus anthracis, the etiologic agents of plague and anthrax, respectively. Comparable sensitivity and rapidity was observed when phage amplification was adapted to a species-specific handheld LFI detector, thus allowing for rapid, simple, POC bacterial detection and identification while eliminating the need for bacterial culturing or DNA isolation and amplification techniques.

Enhanced Sensitivity to Rapid Input Fluctuations by Nonlinear Threshold Dynamics in Neocortical Pyramidal Neurons

PubMed Central

Mensi, Skander; Hagens, Olivier; Gerstner, Wulfram; Pozzorini, Christian

2016-01-01

The way in which single neurons transform input into output spike trains has fundamental consequences for network coding. Theories and modeling studies based on standard Integrate-and-Fire models implicitly assume that, in response to increasingly strong inputs, neurons modify their coding strategy by progressively reducing their selective sensitivity to rapid input fluctuations. Combining mathematical modeling with in vitro experiments, we demonstrate that, in L5 pyramidal neurons, the firing threshold dynamics adaptively adjust the effective timescale of somatic integration in order to preserve sensitivity to rapid signals over a broad range of input statistics. For that, a new Generalized Integrate-and-Fire model featuring nonlinear firing threshold dynamics and conductance-based adaptation is introduced that outperforms state-of-the-art neuron models in predicting the spiking activity of neurons responding to a variety of in vivo-like fluctuating currents. Our model allows for efficient parameter extraction and can be analytically mapped to a Generalized Linear Model in which both the input filter—describing somatic integration—and the spike-history filter—accounting for spike-frequency adaptation—dynamically adapt to the input statistics, as experimentally observed. Overall, our results provide new insights on the computational role of different biophysical processes known to underlie adaptive coding in single neurons and support previous theoretical findings indicating that the nonlinear dynamics of the firing threshold due to Na+-channel inactivation regulate the sensitivity to rapid input fluctuations. PMID:26907675

Nicergoline inhibits T-type Ca2+ channels in rat isolated hippocampal CA1 pyramidal neurones.

PubMed Central

Takahashi, K.; Akaike, N.

1990-01-01

1. The effects of nicergoline on the T- and L-type Ca2+ currents in pyramidal cells freshly isolated from rat hippocampal CA1 region were investigated by use of a 'concentration-clamp' technique. The technique combines a suction-pipette technique, which allows intracellular perfusion under a single-electrode voltage-clamp, and rapid exchange of extracellular solution within 2 ms. 2. T-type Ca2+ currents were evoked by step depolarizations from a holding potential of -100 mV to potentials more positive than -70 to -60 mV, and reached a peak at about -30 mV in the current-voltage relationship. Activation and inactivation of T-type Ca2+ currents were highly potential-dependent. 3. Nicergoline and other Ca2+ antagonists dose-dependently blocked the T-type Ca2+ channel with an order of potency nicardipine greater than nicergoline greater than diltiazem. 4. The L-type Ca2+ channel was also blocked in the order nicardipine greater than nicergoline greater than diltiazem, although the T-type Ca2+ channel was more sensitive to nicergoline. 5. The inhibitory effects of nicergoline and nicardipine on the T-type Ca2+ current were voltage-, time-, and use-dependent, and the inhibition increased with a decrease in the external Ca2+ concentration. Diltiazem showed only a use-dependent block. PMID:2169937

Nicergoline inhibits T-type Ca2+ channels in rat isolated hippocampal CA1 pyramidal neurones.

PubMed

Takahashi, K; Akaike, N

1990-08-01

1. The effects of nicergoline on the T- and L-type Ca2+ currents in pyramidal cells freshly isolated from rat hippocampal CA1 region were investigated by use of a 'concentration-clamp' technique. The technique combines a suction-pipette technique, which allows intracellular perfusion under a single-electrode voltage-clamp, and rapid exchange of extracellular solution within 2 ms. 2. T-type Ca2+ currents were evoked by step depolarizations from a holding potential of -100 mV to potentials more positive than -70 to -60 mV, and reached a peak at about -30 mV in the current-voltage relationship. Activation and inactivation of T-type Ca2+ currents were highly potential-dependent. 3. Nicergoline and other Ca2+ antagonists dose-dependently blocked the T-type Ca2+ channel with an order of potency nicardipine greater than nicergoline greater than diltiazem. 4. The L-type Ca2+ channel was also blocked in the order nicardipine greater than nicergoline greater than diltiazem, although the T-type Ca2+ channel was more sensitive to nicergoline. 5. The inhibitory effects of nicergoline and nicardipine on the T-type Ca2+ current were voltage-, time-, and use-dependent, and the inhibition increased with a decrease in the external Ca2+ concentration. Diltiazem showed only a use-dependent block.

Rapid diagnosis of equine influenza by highly sensitive silver amplification immunochromatography system.

PubMed

Yamanaka, Takashi; Nemoto, Manabu; Bannai, Hiroshi; Tsujimura, Koji; Kondo, Takashi; Matsumura, Tomio; Fu, Tao Qi Huang; Fernandez, Charlene Judith; Gildea, Sarah; Cullinane, Ann

2017-06-16

Equine influenza (EI) is a respiratory disease caused by equine influenza A virus (EIV, H3N8) infection. Rapid diagnosis is essential to limit the disease spread. We previously reported that some rapid antigen detection (RAD) tests are fit for diagnosing EI although their sensitivity is not optimal. Here, we evaluated the performance of the newly developed RAD test using silver amplification immunochromatography (Quick Chaser Auto Flu A, B: QCA) to diagnose EI. The detection limits of QCA for EIVs were five-fold lower than the conventional RAD tests. The duration of virus antigen detection in the infected horses was longer than the conventional RAD tests. We conclude that QCA could be a valuable diagnostic method for EI.

Rapid detection of Escherichia coli O157:H7 using tunneling magnetoresistance biosensor

NASA Astrophysics Data System (ADS)

Wu, Yuanzhao; Liu, Yiwei; Zhan, Qingfeng; Liu, J. Ping; Li, Run-Wei

2017-05-01

A rapid method for the sensitive detection of bacteria using magnetic immunoassay, which are measured with a tunneling magnetoresistance (TMR) sensor, is described. For the measurement of Escherichia coli O157:H7 (E. coli O157:H7) bacteria, the target was labeled by magnetic beads through magnetic immunoassay. The magnetic beads produce a weak magnetic fringe field when external field is applied, thus induce the magnetoresistance change of TMR sensor. A detection limit of 100 CFU/mL E. coli O157:H7 bacteria in 5 hours was obtained. With its high sensitive and rapid detection scheme based on the TMR biosensor, the detection system is an excellent candidate suitable and promising for food safety and biomedical detection.

Characterisation of rapid progressors to type 1 diabetes among children with HLA-conferred disease susceptibility.

PubMed

Pöllänen, Petra M; Lempainen, Johanna; Laine, Antti-Pekka; Toppari, Jorma; Veijola, Riitta; Vähäsalo, Paula; Ilonen, Jorma; Siljander, Heli; Knip, Mikael

2017-07-01

In this study, we aimed to characterise rapid progressors to type 1 diabetes among children recruited from the general population, on the basis of HLA-conferred disease susceptibility. We monitored 7410 HLA-predisposed children participating in the Finnish Type 1 Diabetes Prediction and Prevention (DIPP) study for the development of beta cell autoimmunity and type 1 diabetes from birth over a median follow-up time of 16.2 years (range 0.9-21.1 years). Islet cell antibodies (ICA) and autoantibodies to insulin (IAA), GAD (GADA) and islet antigen 2 (IA-2A) were assessed as markers of beta cell autoimmunity. Rapid progression was defined as progression to clinical type 1 diabetes within 1.5 years of autoantibody seroconversion. We analysed the association between rapid progression and demographic and autoantibody characteristics as well as genetic markers, including 25 non-HLA SNPs predisposing to type 1 diabetes. Altogether, 1550 children (21%) tested positive for at least one diabetes-associated autoantibody in at least two samples, and 248 (16%) of seroconverters progressed to type 1 diabetes by the end of 2015. The median time from seroconversion to diagnosis was 0.51 years in rapid progressors (n = 42, 17%) and 5.4 years in slower progressors. Rapid progression was observed both among young (<5 years) and early pubertal children (>7 years), resulting in a double-peak distribution of seroconversion age. Compared with slower progressors, rapid progressors had a higher frequency of positivity for multiple (≥2) autoantibodies and had higher titres of ICA, IAA and IA-2A at seroconversion, and there was a higher prevalence of the secretor genotype in the FUT2 gene among those carrying the high-risk HLA genotype. Compared with autoantibody-positive non-progressors, rapid progressors were younger, were more likely to carry the high-risk HLA genotype and a predisposing SNP in the PTPN22 gene, had higher frequency of ICA, IAA, GADA and IA-2A positivity and multipositivity, and had higher titres of all four autoantibodies at seroconversion. At seroconversion, individuals with rapid progression to type 1 diabetes were characterised by a younger age, higher autoantibody titres, positivity for multiple autoantibodies and higher prevalence of a FUT2 SNP. The double-peak profile for seroconversion age among the rapid progressors demonstrates for the first time that rapid progression may take place not only in young children but also in children in early puberty. Rapid progressors might benefit from careful clinical follow-up and early preventive measures.

Rapid detection of bacteria in foods and biological fluids

NASA Technical Reports Server (NTRS)

Fealey, R. D.; Renner, W.

1973-01-01

Simple and inexpensive apparatus, called "redox monitoring cell," rapidly detects presence of bacteria. Bacteria is detected by measuring drop in oxygen content in test solution. Apparatus consists of vial with two specially designed electrodes connected to sensitive voltmeter.

Accuracy of an Immunochromatographic Diagnostic Test (ICT Malaria Combo Cassette Test) Compared to Microscopy among under Five-Year-Old Children when Diagnosing Malaria in Equatorial Guinea

PubMed Central

Portero, José-Luis; Rubio-Yuste, Maria; Descalzo, Miguel Angel; Raso, Jose; Lwanga, Magdalena; Obono, Jaquelina; Nseng, Gloria; Benito, Agustin; Cano, Jorge

2010-01-01

Conventional malaria diagnosis based on microscopy raises serious difficulties in weak health systems. Cost-effective and sensitive rapid diagnostic tests have been recently proposed as alternatives to microscopy. In Equatorial Guinea, a study was conducted to assess the reliability of a rapid diagnostic test compared to microscopy. The study was designed in accordance with the directives of the Standards for Reporting Diagnostic Accuracy Initiative (STARD). Peripheral thick and thin films for the microscopy diagnosis and a rapid immunochromatographic test (ICT Malaria Combo Cassette Test) were performed on under five-year-old children with malaria suspicion. The ICT test detected Plasmodium spp. infection with a sensitivity of 81.5% and a specificity of 81.9% while P. falciparum diagnosis occurred with a sensitivity of 69.7% and a specificity of 73.7%. The sensitivity of the ICT test increased with higher parasitemias. The general results showed little concordance between the ICT test and microscopy (kappa = 0.28, se: 0.04). In Equatorial Guinea, the ICT Malaria Combo Cassette Test has proven to be an acceptable test to detect high P. falciparum parasitemias. However, the decrease of sensitivity at medium and low parasitemias hampers that ICT can replace properly performed microscopy at present in the diagnosis of malaria in children. PMID:22332024