Method For Detection Of Viable Research Articles

Targeted Next-Generation Sequencing for Comprehensive Testing for Selected Vector-Borne Pathogens in Canines.

The standard for detecting vector-borne pathogens is real-time PCR (rtPCR). However, this requires many individual tests to obtain an accurate diagnosis. The purpose of this study was to develop and validate a targeted next-generation sequencing (NGS) assay for vector-borne pathogens. Pathogen target regions were amplified via PCR using two primer pools that were developed in conjunction with ThermoFisher Scientific, and barcoded DNA libraries were prepared and sequenced with the Ion Torrent S5 system. Data were assembled using SPAdes and mapped to a reference file containing sequences from the pathogens. The raw reads were analyzed to confirm the results. Test feasibility and analytical specificity were evaluated with type strains or validated positive clinical samples from dogs. The analytical sensitivity of the method was compared to Ct values obtained by rtPCR testing. Diagnostic sensitivity and specificity were assessed with a set of known positive and negative clinical samples based on rtPCR testing. Positive and negative percent agreements and Cohen’s kappa were calculated. The primer sets were specific for the intended targets, based on sequence analysis of the amplified products, and the method detected 17 different pathogens. Analytical sensitivity was equivalent to an rtPCR Ct value of approximately 35–36. The positive percent agreement was 92%, and the negative percent agreement was 88%. Cohen’s kappa was 0.804, which indicates almost perfect agreement between the rtPCR assays and the targeted NGS assay. Using a targeted method reduces the costs associated with NGS sequencing and allows for a 2–3 day turn-around time, making this a viable method for detection of vector-borne pathogens in canine whole blood samples.

Trichomonas vaginalis Detection Using Two Convolutional Neural Networks with Encoder-Decoder Architecture

Diagnosis of Trichomonas vaginalis infection is one of the most important factors in the routine examination of leucorrhea. According to the motion characteristics of Trichomonas vaginalis, a viable detection method is the use of a microscopic camera to record videos of leucorrhea samples and video object detection algorithms for detection. Most Trichomonas vaginalis is defocused and displays as shadow regions on microscopic images, and it is hard to recognize the movement of shadow regions using traditional video object detection algorithms. In order to solve this problem, we propose two convolutional neural networks based on an encoder-decoder architecture. The first network has the ability to learn the difference between frames and utilizes the image and optical flow information of three consecutive frames as the input to perform rough detection. The second network corrects the coarse contours and uses the image information and the rough detection result of the current frame as the input to perform fine detection. With these two networks applied, the metric value of the mean intersection over union of Trichomonas vaginalis achieves 72.09% on test videos. The proposed networks can effectively detect defocused Trichomonas vaginalis and suppress false alarms caused by the motion of formed elements or impurities.

Contrast enhanced X-ray computed tomography imaging of amyloid plaques in Alzheimer disease rat model on lab based micro CT system

Amyloid plaques are small (~ 50 μm), highly-dense aggregates of amyloid beta (Aβ) protein in brain tissue, supposed to play a key role in pathogenesis of Alzheimer’s disease (AD). Plaques´ in vivo detection, spatial distribution and quantitative characterization could be an essential marker in diagnostics and evaluation of AD progress. However, current imaging methods in clinics possess substantial limits in sensitivity towards Aβ plaques to play a considerable role in AD screening. Contrast enhanced X-ray micro computed tomography (micro CT) is an emerging highly sensitive imaging technique capable of high resolution visualization of rodent brain. In this study we show the absorption based contrast enhanced X-ray micro CT imaging is viable method for detection and 3D analysis of Aβ plaques in transgenic rodent models of Alzheimer’s disease. Using iodine contrasted brain tissue isolated from the Tg-F344-AD rat model we show the micro CT imaging is capable of precise imaging of Aβ plaques, making possible to further analyze various aspects of their 3D spatial distribution and other properties.

Validation of eDNA as a viable method of detection for dangerous cubozoan jellyfish

AbstractStings from certain species of cubozoan jellyfish are dangerous to humans and their seasonal presence in tropical marine waters poses a significant risk to coastal communities. The detection of cubozoans is difficult due to high spatial and temporal variation in their occurrence and abundance. Environmental DNA (eDNA) has the potential to detect rare species and therefore offers potential to detect cubozoans, not only pelagic medusae, but presence of cryptic polyp life stages. The objective of this study was to validate the use of eDNA as a viable detection method for four cubozoan species (Chironex fleckeri, Copula sivickisi, Carybdea xaymacana, and Carukia barnesi). Species‐specific primers were developed for each of these four cubozoans and an eDNA approach validated utilizing both laboratory and field trials. Laboratory DNA degradation experiments demonstrated that C. sivickisi DNA degraded quickly but could still be detected in sea water for up to 9 days post‐jellyfish removal. Positive detection was found for C. fleckeri, C. xaymacana, and C. sivickisi medusae in the waters surrounding Magnetic Island, Queensland, in the Austral spring/summer (September‐January). Based on visual surveys, there was a poor relationship between concentration of eDNA and abundance of jellyfish. Positive eDNA amplification was also found from water sampled near the substratum when C. sivickisi medusae were out of season and absent. This suggests the eDNA analysis was likely detecting C. sivickisi polyps located within the substratum. Consequently, eDNA is an effective tool to detect both the medusae and likely polyps of cubozoans. This approach provides the means to reduce the risk of envenomation to swimmers and enhance our knowledge of cubozoan ecology.

Learning to detect the onset of slow activity after a generalized tonic\u2013clonic seizure

BackgroundSudden death in epilepsy (SUDEP) is a rare disease in US, however, they account for 8–17% of deaths in people with epilepsy. This disease involves complicated physiological patterns and it is still not clear what are the physio-/bio-makers that can be used as an indicator to predict SUDEP so that care providers can intervene and treat patients in a timely manner. For this sake, UTHealth School of Biomedical Informatics (SBMI) organized a machine learning Hackathon to call for advanced solutions https://sbmi.uth.edu/hackathon/archive/sept19.htm.MethodsIn recent years, deep learning has become state of the art for many domains with large amounts data. Although healthcare has accumulated a lot of data, they are often not abundant enough for subpopulation studies where deep learning could be beneficial. Taking these limitations into account, we present a framework to apply deep learning to the detection of the onset of slow activity after a generalized tonic–clonic seizure, as well as other EEG signal detection problems exhibiting data paucity.ResultsWe conducted ten training runs for our full method and seven model variants, statistically demonstrating the impact of each technique used in our framework with a high degree of confidence.ConclusionsOur findings point toward deep learning being a viable method for detection of the onset of slow activity provided approperiate regularization is performed.

Conventional Real Time Quantitative Polymerase Chain Reaction Method Yields Similar Level of Sensitivity to Digital Droplet Polymerase Chain Reaction for Detection of BCR-ABL p210 Transcripts in Patients with Chronic Phase Chronic Myeloid Leukemia

Introduction: Several studies have investigated the utility of digital droplet polymerase chain reaction (ddPCR) in the detection of p210 BCR-ABL fusion transcripts in chronic myeloid leukemia (CML), and have suggested greater sensitivity compared to real-time quantitative PCR (RT-qPCR). There is limited data regarding the utility and sensitivity of ddPCR in patients with chronic phase CML (CP-CML) who are candidates for tyrosine kinase inhibitor (TKI) discontinuation. We aimed to investigate the capability of ddPCR to detect p210 BCR-ABL transcript levels in CP-CML patients and compare the sensitivity to RT-qPCR. Methods: We analyzed 103 different peripheral blood (n=98) and bone marrow (n=5) samples from 36 patients with CP-CML treated at Moffitt Cancer Center between 2013 and 2018. Samples were from patients who either met clinical criteria for TKI discontinuation or were enrolled in a phase I dose-escalation study evaluating combination therapy with nilotinib plus ruxolitinib who had at least a complete cytogenetic response (CCyR) to TKI therapy with detectable BCR-ABL transcripts by RT-PCR at the time of enrollment(1, 2). BCR-ABL levels were assessed by RT-qPCR at the time of collection with level of transcript reported as % International Standard (%IS). Samples collected from 2013 to 2014 were reported as p210 to ABL and converted to %IS per lab-specific conversion factor. Stored purified RNA samples were obtained retrospectively and ddPCR was performed using the QX-200 Droplet Digital PCR System and QXDx BCR-ABL %IS Kit (Bio-Rad). Droplets were analyzed by QXDx BCR-ABL reporter software to determine p210 transcript level (%IS). Analysis for RNA degradation of stored samples was performed via High Sensitivity RNA ScreenTape (Agilent). Samples that did not pass quality check upon performing ddPCR were excluded from further analysis. Correlation coefficient was calculated with p-value of <0.05 being significant. Results: Of the 36 patients, 28 were in the TKI discontinuation cohort and 10 were enrolled in the clinical trial of nilotinib plus ruxolitinib. Two patients who participated in the clinical trial subsequently also met criteria for TKI discontinuation. In the TKI discontinuation cohort, 46% of patients (n=13) lost major molecular response (MMR) with a median time to loss of MMR of 88 days. We observed a statistically significant correlation between RT-qPCR and ddPCR levels when comparing %IS (correlation coefficient R2=0.42; p<0.0001) as well as calculated molecular response (MR) logarithm values of all available samples (R2=0.67; p <0.0001) (Figure 1). There was a weaker correlation between patients determined to have MMR by RT-qPCR (MR≥3.0) compared to ddPCR (R2=0.55; p <0.0001) (Figure 2). A total of 91 different samples were consistent with MMR when tested by RT-PCR. Of these samples, 85.7% (n=78) were consistent with MMR when tested by ddPCR and the remaining 14.3% (n=13) appeared to have higher detectable levels of p210 transcripts (MR<3.0). When investigating deeper molecular responses, 62 samples were consistent with MR≥4.0 by RT-PCR, and 20.9% (n=13) of these samples did not achieve a deep molecular response (MR<4.0) when tested by ddPCR. Of note, 5 representative samples were also evaluated for potential RNA degradation and 3 were noted to have significant degradation present. Conclusion: Compared to RT-PCR, ddPCR represents a viable method for detection of p210 transcripts for patients with CP-CML. The two methods yield similar efficacy when detecting varying levels of molecular response, however further research is warranted for the ability to detect deeper molecular responses for patients in MMR. Our study is limited by inherent retrospective bias and quality of RNA in stored samples. 1. National Comprehensive Cancer Network. Chronic Myeloid Leukemia (Version 1.2019). 2. Sweet K, Hazlehurst L, Sahakian E, Powers J, Nodzon L, Kayali F, et al. A phase I clinical trial of ruxolitinib in combination with nilotinib in chronic myeloid leukemia patients with molecular evidence of disease. Leuk Res. 2018;74:89-96. Disclosures Talati: Jazz Pharmaceuticals: Honoraria, Speakers Bureau; Daiichi-Sankyo: Honoraria; Astellas: Honoraria, Speakers Bureau; Pfizer: Honoraria; Celgene: Honoraria; Agios: Honoraria. Shelton:Bio-Rad: Employment. Nodzon:Pharmacyclics: Consultancy; Abbvie: Other: Speaker Fees; Genentech: Consultancy, Other: Speaker Fees; Pfizer: Consultancy. Sweet:Stemline: Consultancy; Pfizer: Consultancy; Abbvie: Membership on an entity's Board of Directors or advisory committees; Celgene: Speakers Bureau; Bristol Myers Squibb: Membership on an entity's Board of Directors or advisory committees; Astellas: Membership on an entity's Board of Directors or advisory committees; Incyte: Research Funding; Jazz: Speakers Bureau; Novartis: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Agios: Membership on an entity's Board of Directors or advisory committees. Pinilla Ibarz:Novartis: Consultancy; Abbvie: Consultancy, Speakers Bureau; Takeda: Consultancy, Speakers Bureau; Bristol-Myers Squibb: Consultancy; Janssen: Consultancy, Speakers Bureau; Bayer: Speakers Bureau; TG Therapeutics: Consultancy; Teva: Consultancy; Sanofi: Speakers Bureau.

A flow cytometric analysis of macrophage- nanoparticle interactions in vitro: induction of altered Toll-like receptor expression.

BackgroundNanoparticles exhibit unique physiochemical characteristics that provide the basis for their utilization. The diversity of potential and actual applications compels a thorough understanding regarding the consequences of their containment within the cellular environment.PurposeThis paper presents a flow cytometric examination of the biologic effects associated with the internalization of citrate-buffered silver (Ag) nanoparticles (NP) by the murine macrophage cell line, RAW264.7.Materials and methodsCells were cultured with varying concentrations of citrate-buffered Ag nanoparticle and analyzed for changes in cellular volume, fluorescence emissions, and surface receptor expression.ResultsNotable changes in side scatter (SSC) signal occurred following the phagocytosis of citrate-buffered Ag NP representative of the 10 nm, 50 nm, and 100 nm particle size by cultured RAW 264.7 cells. A characteristic associated with the internalization of all the citrated Ag NP sizes tested, was the detection of emitted infra-red and near-infrared wavelength emissions. This characteristic consistently permitted the detection of 10 nm, 50 nm, and 100 nm Ag NP particles internalized within the RAW cells by flow cytometry. A functional distinction between monocyte subsets within the RAW 264.7 cell line was noted as Ag NP are taken up by the F4/80+ subset of cells within the culture. Further, the internalization of Ag NP by the cells resulted in an increased cell surface expression of the Toll-like receptor (TLR) 3, but not TLR4.ConclusionTaken together, these results implicate the more mature macrophage in the ingestion of Ag NP; and an influence upon at least one of the Toll receptors present in macrophages following exposure to Ag NP. Further, our flow cytometric approach presents a potentially viable detection method for the identification of occult Ag NP material using an indicator cell line.

Dynamics of the A-band ultraviolet photodissociation of methyl iodide and ethyl iodide via velocity-map imaging with 'universal' detection.

We report data from a comprehensive investigation into the photodissociation dynamics of methyl iodide and ethyl iodide at several wavelengths in the range 236-266 nm, within their respective A-bands. The use of non-resonant single-photon ionization at 118.2 nm allows detection and velocity-map imaging of all fragments, regardless of their vibrotational or electronic state. The resulting photofragment kinetic energy and angular distributions and the quantum yields of ground-state and spin-orbit excited iodine fragments are in good agreement with previous studies employing state-selective detection via REMPI. The data are readily rationalised in terms of three competing dissociation mechanisms. The dominant excitation at all wavelengths studied is via a parallel transition to the (3)Q0 state, which either dissociates directly to give an alkyl radical partnered by spin-orbit excited iodine, or undergoes radiationless transfer to the (1)Q1 potential surface, where it dissociates to an alkyl radical partnered by iodine in its electronic ground state. Ground state iodine atoms can also be formed by direct dissociation from the (1)Q1 or (3)Q1 excited states following perpendicular excitation at the shorter and longer wavelength region, respectively, in the current range of interest. The extent of internal excitation of the alkyl fragment varies with dissociation mechanism, and is considerably higher for ethyl fragments from ethyl iodide photolysis than for methyl fragments from methyl iodide photolysis. We discuss the relative advantages and disadvantages of single-photon vacuum-ultraviolet ionization relative to the more widely used REMPI detection schemes, and conclude, in agreement with others, that single-photon ionization is a viable detection method for photofragment imaging studies, particularly when studying large molecules possessing multiple fragmentation channels.

Detection of two equine trisomies using SNP-CGH

Chromosomal aberrations in the horse are known to cause congenital abnormalities, embryonic loss, and infertility. While diagnosed mainly by karyotyping and FISH in the horse, the use of SNP array comparative genome hybridization (SNP-CGH) is becoming increasingly common in human diagnostics. Normalized probe intensities and allelic ratios are used to detect changes in copy number genome-wide. Two horses with suspected chromosomal abnormalities and six horses with FISH-confirmed aberrant karyotypes were chosen for genotyping on the Equine SNP50 array. Karyotyping of the first horse indicated mosaicism for an additional small, acrocentric chromosome, although the identity of the chromosome was unclear. The second case displayed a similar phenotype to human disease caused by a gene deletion and so was chosen for SNP-CGH due to the ability to detect changes at higher resolutions than those achieved with conventional karyotyping. The results of SNP-CGH analysis for the six horses with known chromosomal aberrations agreed completely with previous karyotype and FISH analysis. The first undiagnosed case showed a pattern of altered allelic ratios without a noticeable shift in overall intensity for chromosome 27, consistent with a mosaic trisomy. The second case displayed a more drastic change in both values for chromosome 30, consistent with a complete trisomy. These results indicate that SNP-CGH is a viable method for detection of chromosomal aneuploidies in the horse.

Detection of Non-PCR Amplified S. enteritidis Genomic DNA from Food Matrices Using a Gold-Nanoparticle DNA Biosensor: A Proof-of-Concept Study

Bacterial pathogens pose an increasing food safety and bioterrorism concern. Current DNA detection methods utilizing sensitive nanotechnology and biosensors have shown excellent detection, but require expensive and time-consuming polymerase chain reaction (PCR) to amplify DNA targets; thus, a faster, more economical method is still essential. In this proof-of-concept study, we investigated the ability of a gold nanoparticle-DNA (AuNP-DNA) biosensor to detect non-PCR amplified genomic Salmonella enterica serovar Enteritidis (S. enteritidis) DNA, from pure or mixed bacterial culture and spiked liquid matrices. Non-PCR amplified DNA was hybridized into sandwich-like structures (magnetic nanoparticles/DNA/AuNPs) and analyzed through detection of gold voltammetric peaks using differential pulse voltammetry. Our preliminary data indicate that non-PCR amplified genomic DNA can be detected at a concentration as low as 100 ng/mL from bacterial cultures and spiked liquid matrices, similar to reported PCR amplified detection levels. These findings also suggest that AuNP-DNA biosensors are a first step towards a viable detection method of bacterial pathogens, in particular, for resource-limited settings, such as field-based or economically limited conditions. Future efforts will focus on further optimization of the DNA extraction method and AuNP-biosensors, to increase sensitivity at lower DNA target concentrations from food matrices comparable to PCR amplified DNA detection strategies.

Detection of Cellular Sialic Acid Content Using Nitrobenzoxadiazole Carbonyl-Reactive Chromophores

The selective ligation of hydrazine and amino-oxy compounds with carbonyls has gained popularity as a detection strategy with the recognition of aniline catalysis as a way to accelerate the labeling reaction in water. Aldehydes are a convenient functional group choice since there are few native aldehydes found at the cell surface. Aldehydes can be selectively introduced into sialic acid containing glycoproteins by treatment with dilute sodium periodate. Thus, the combination of periodate oxidation with aniline-catalyzed ligation (PAL) has become a viable method for detection of glycoconjugates on live cells. Herein we examine two fluorescent nitrobenzoxadiazole dyes for labeling of glycoproteins and cell surface glycoconjugates. We introduce a novel 4-aminooxy-7-nitro-benz-[2,1,3-d]-oxadiazole (NBDAO) (5) fluorophore, and offer a comparison to commercial dyes including the known 4-hydrazino-7-nitro-benz-[2,1,3-d]-oxadiazole (NBDH) (2) and Bodipy FL hydrazide. We confirm specificity for sialic acid moieties and that both dyes are suitable for in vitro and in vivo labeling studies using PAL and fluorescence spectroscopy. The dyes examined here are attractive labeling agents for microscopy, as they can be excited by a 488 nm laser line and can be made in a few synthetic steps. These carbonyl-reactive chromophores provide a one step alternative to avidin-biotin labeling strategies and simplify the detection of sialic acid in cells and glycoproteins.