scholarly journals Evaluation of a High-Throughput Fluorescence Assay Method for hERG Potassium Channel Inhibition

2005 ◽  
Vol 10 (4) ◽  
pp. 339-347 ◽  
Author(s):  
Arnulf Dorn ◽  
Francis Hermann ◽  
Andreas Ebneth ◽  
Hendrick Bothmann ◽  
Gerhard Trube ◽  
...  
Keyword(s):  
Drug Development ◽  
Potassium Channel ◽  
Fluorescent Dyes ◽  
False Negative ◽  
Qt Prolongation ◽  
Fluorescence Assay ◽  
Assay Method ◽  
Cardiac Side Effects ◽  
Channel Inhibition ◽  
Wide Range

The number of projects in drug development that fail in late phases because of cardiac side effects such as QT prolongation can impede drug discovery and development of projects. The molecular target responsible for QT prolongation by a wide range of pharmaceutical agents is the myocardial hERG potassium channel. It is therefore desirable to screen for compound interactions with the hERG channel at an early stage of drug development. Here, the authors report a cell-based fluorescence assay using membrane potential-sensitive fluorescent dyes and stably transfected hERG channels from CHO cells. The assay allows semiautomated screening of compounds for hERG activity on 384-well plates and is sufficiently rapid for testing a large number of compounds. The assay is robust as indicated by a Z′ factor larger than 0.6. The throughput is in the range of 10,000 data points per day, which is significantly higher than any other method presently available for hERG. The data obtained with the fluorescence assay were in qualitative agreement with those from patch-clamp electrophysiological analysis. There were no false-positive hits, and the rate of false-negative compounds is currently 12% but might be further reduced by testing compounds at higher concentration. Quantitative differences between fluorescence and electrophysiological methods may be due to the use- or voltage-dependentactivity of the antagonists.

scholarly journals hERG potassium channel inhibition by ivabradine may contribute to QT prolongation and risk of torsades de pointes

2015 ◽  
Vol 6 (4) ◽  
pp. 177-179 ◽  
Author(s):  
Jules C. Hancox ◽  
Dario Melgari ◽  
Christopher E. Dempsey ◽  
Kieran E. Brack ◽  
John Mitcheson ◽  
...  
Keyword(s):  
Potassium Channel ◽  
Torsades De Pointes ◽  
Qt Prolongation ◽  
Channel Inhibition

Extending the Applicability of the ANI Deep Learning Molecular Potential to Sulfur and Halogens

2020 ◽  
Author(s):  
Christian Devereux ◽  
Justin Smith ◽  
Kate Davis ◽  
Kipton Barros ◽  
Roman Zubatyuk ◽  
...  
Keyword(s):  
Drug Development ◽  
Autonomous Vehicles ◽  
Potential Energy Surfaces ◽  
Organic Molecules ◽  
Chemical Elements ◽  
Molecular Potential ◽  
Wide Range ◽  
Energy Surfaces ◽  
New Applications ◽  
Physical Phenomena

<p>Machine learning (ML) methods have become powerful, predictive tools in a wide range of applications, such as facial recognition and autonomous vehicles. In the sciences, computational chemists and physicists have been using ML for the prediction of physical phenomena, such as atomistic potential energy surfaces and reaction pathways. Transferable ML potentials, such as ANI-1x, have been developed with the goal of accurately simulating organic molecules containing the chemical elements H, C, N, and O. Here we provide an extension of the ANI-1x model. The new model, dubbed ANI-2x, is trained to three additional chemical elements: S, F, and Cl. Additionally, ANI-2x underwent torsional refinement training to better predict molecular torsion profiles. These new features open a wide range of new applications within organic chemistry and drug development. These seven elements (H, C, N, O, F, Cl, S) make up ~90% of drug like molecules. To show that these additions do not sacrifice accuracy, we have tested this model across a range of organic molecules and applications, including the COMP6 benchmark, dihedral rotations, conformer scoring, and non-bonded interactions. ANI-2x is shown to accurately predict molecular energies compared to DFT with a ~10<sup>6</sup> factor speedup and a negligible slowdown compared to ANI-1x. The resulting model is a valuable tool for drug development that can potentially replace both quantum calculations and classical force fields for myriad applications.</p>

scholarly journals In vitro activities of Acacia nilotica (L.) Delile bark fractions against Oral Bacteria, Glucosyltransferase and as antioxidant

2020 ◽  
Vol 20 (1) ◽  
Author(s):  
Ali Mahmoud Muddathir ◽  
Ebtihal Abdalla M. Mohieldin ◽  
Tohru Mitsunaga
Keyword(s):  
Antioxidant Activity ◽  
Antibacterial Activity ◽  
Gallic Acid ◽  
Crude Extract ◽  
Inhibitory Activity ◽  
Oral Bacteria ◽  
Acacia Nilotica ◽  
Assay Method ◽  
Medicinal Uses ◽  
Wide Range

Abstract Background Dental caries and periodontal disease are the most common chronic infectious oral diseases in the world. Acacia nilotica was commonly known in Sudan as Garad or Sunt has a wide range of medicinal uses. In the present study, antibacterial activity of oral bacteria (Streptococcus sobrinus and Porphyromonas gingivalis), inhibitory activity against glucosyltransferase (GTF) enzyme and antioxidant activity were assayed for methanolic crude extract of A. nilotica bark and its fractions. Methods Methanoilc crude extract of A. nilotica bark was applied to a Sephadex LH-20 column and eluted with methanol, aqueous methanol, and finally aqueous acetone to obtain four fractions (Fr1- Fr4). Furthermore, the crude extract and fractions were subjected to analytical high performance liquid chromatography (HPLC). The crude extract and its fractions were assayed for antibacterial activity against S. sobrinus and P. gingivalis using a microplate dilution assay method to determine the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC), as well as GTF inhibition and antioxidant activity using ABTS radical scavenging method. Results Fractions (Fr1 and Fr2) exhibited MIC values of 0.3 mg/ml against the P. gingivalis. Additionally, Fr2 displayed MBC value of 1 mg/ml against two types of bacteria. Fr4 showed an especially potent GTF inhibitory activity with IC50 value of 3.9 μg/ml. Fr1 displayed the best antioxidant activity with IC50 value of 1.8 μg/ml. The main compound in Fr1 was identified as gallic acid, and Fr2 was mostly a mixture of gallic acid and methyl gallate. Conclusions The results obtained in this study provide some scientific rationale and justify the use of this plant for the treatment of dental diseases in traditional medicine. A. nilotica bark, besides their antibacterial potentiality and GTF inhibitory activity, it may be used as adjuvant antioxidants in mouthwashes. Further studies in the future are required to identify the rest of the active compounds.

EXPRESS: Method dependent variation in TSH and FT4 reference intervals in pregnancy: a systematic review

2021 ◽  
pp. 000456322110269
Author(s):  
O E Okosieme ◽  
Medha Agrawal ◽  
Danyal Usman ◽  
Carol Evans
Keyword(s):  
Systematic Review ◽  
Reference Interval ◽  
First Trimester ◽  
Reference Intervals ◽  
Assay Method ◽  
Specific Reference ◽  
Upper Limits ◽  
Wide Range ◽  
Assay Methods ◽  
In Pregnancy

Background: Gestational TSH and FT4 reference intervals may differ according to assay method but the extent of variation is unclear and has not been systematically evaluated. We conducted a systematic review of published studies on TSH and FT4 reference intervals in pregnancy. Our aim was to quantify method-related differences in gestation reference intervals, across four commonly used assay methods, Abbott, Beckman, Roche, and Siemens. Methods: We searched the literature for relevant studies, published between January 2000 and December 2020, in healthy pregnant women without thyroid antibodies or disease. For each study, we extracted trimester-specific reference intervals (2.5–97.5 percentiles) for TSH and FT4 as well as the manufacturer provided reference interval for the corresponding non-pregnant population. Results: TSH reference intervals showed a wide range of study-to-study differences with upper limits ranging from 2.33 to 8.30 mU/L. FT4 lower limits ranged from 4.40–13.93 pmol/L, with consistently lower reference intervals observed with the Beckman method. Differences between non-pregnant and first trimester reference intervals were highly variable, and for most studies the TSH upper limit in the first trimester could not be predicted or extrapolated from non-pregnant values. Conclusions: Our study confirms significant intra and inter-method disparities in gestational thyroid hormone reference intervals. The relationship between pregnant and non-pregnant values is inconsistent and does not support the existing practice in some laboratories of extrapolating gestation references from non-pregnant values. Laboratories should invest in deriving method-specific gestation reference intervals for their population.

Adaptive intelligent learning approach based on visual anti-spam email model for multi-natural language

2021 ◽  
Vol 30 (1) ◽  
pp. 774-792
Author(s):  
Mazin Abed Mohammed ◽  
Dheyaa Ahmed Ibrahim ◽  
Akbal Omran Salman
Keyword(s):  
Natural Language ◽  
Naive Bayes ◽  
False Negative ◽  
Naïve Bayes ◽  
Final Decision ◽  
Learning Approach ◽  
Naive Bayes Classifier ◽  
Bayes Classifier ◽  
Naïve Bayes Classifier ◽  
Wide Range

Abstract Spam electronic mails (emails) refer to harmful and unwanted commercial emails sent to corporate bodies or individuals to cause harm. Even though such mails are often used for advertising services and products, they sometimes contain links to malware or phishing hosting websites through which private information can be stolen. This study shows how the adaptive intelligent learning approach, based on the visual anti-spam model for multi-natural language, can be used to detect abnormal situations effectively. The application of this approach is for spam filtering. With adaptive intelligent learning, high performance is achieved alongside a low false detection rate. There are three main phases through which the approach functions intelligently to ascertain if an email is legitimate based on the knowledge that has been gathered previously during the course of training. The proposed approach includes two models to identify the phishing emails. The first model has proposed to identify the type of the language. New trainable model based on Naive Bayes classifier has also been proposed. The proposed model is trained on three types of languages (Arabic, English and Chinese) and the trained model has used to identify the language type and use the label for the next model. The second model has been built by using two classes (phishing and normal email for each language) as a training data. The second trained model (Naive Bayes classifier) has been applied to identify the phishing emails as a final decision for the proposed approach. The proposed strategy is implemented using the Java environments and JADE agent platform. The testing of the performance of the AIA learning model involved the use of a dataset that is made up of 2,000 emails, and the results proved the efficiency of the model in accurately detecting and filtering a wide range of spam emails. The results of our study suggest that the Naive Bayes classifier performed ideally when tested on a database that has the biggest estimate (having a general accuracy of 98.4%, false positive rate of 0.08%, and false negative rate of 2.90%). This indicates that our Naive Bayes classifier algorithm will work viably on the off chance, connected to a real-world database, which is more common but not the largest.

scholarly journals WIN55,212-2, a Dual Modulator of Cannabinoid Receptors and G Protein-Coupled Inward Rectifier Potassium Channels

Biomedicines ◽  
2021 ◽  
Vol 9 (5) ◽  
pp. 484
Author(s):  
Dongchen An ◽  
Steve Peigneur ◽  
Jan Tytgat
Keyword(s):  
Potassium Channels ◽  
Potassium Channel ◽  
G Protein ◽  
Cannabinoid Receptors ◽  
Inward Rectifier ◽  
Xenopus Laevis Oocyte ◽  
Inward Rectifier Potassium Channels ◽  
Wide Range ◽  
Cb2 Receptors ◽  
G Protein Coupled

The coupling of cannabinoid receptors, CB1 and CB2, to G protein-coupled inward rectifier potassium channels, GIRK1 and GIRK2, modulates neuronal excitability in the human brain. The present study established and validated the functional expression in a Xenopus laevis oocyte expression system of CB1 and CB2 receptors, interacting with heteromeric GIRK1/2 channels and a regulator of G protein signaling, RGS4. This ex vivo system enables the discovery of a wide range of ligands interacting orthosterically or allosterically with CB1 and/or CB2 receptors. WIN55,212-2, a non-selective agonist of CB1 and CB2, was used to explore the CB1- or CB2-GIRK1/2-RGS4 signaling cascade. We show that WIN55,212-2 activates CB1 and CB2 at low concentrations whereas at higher concentrations it exerts a direct block of GIRK1/2. This illustrates a dual modulatory function, a feature not described before, which helps to explain the adverse effects induced by WIN55,212-2 in vivo. When comparing the effects with other typical cannabinoids such as Δ9-THC, CBD, CP55,940, and rimonabant, only WIN55,212-2 can significantly block GIRK1/2. Interestingly, the inward rectifier potassium channel, IRK1, a non-G protein-coupled potassium channel important for setting the resting membrane voltage and highly similar to GIRK1 and GIRK2, is not sensitive to WIN55,212-2, Δ9-THC, CBD, CP55,940, or rimonabant. From this, it is concluded that WIN55,212-2 selectively blocks GIRK1/2.

P–530 The use of wide thresholds for detecting intermediate chromosomal CNV up to 80% doesn’t improve PGT-A ability to discriminate true mosaic from uniformly aneuploid embryos

2021 ◽  
Vol 36 (Supplement_1) ◽  
Author(s):  
L Girardi ◽  
M Serdaroğulları ◽  
C Patassini ◽  
S Caroselli ◽  
M Costa ◽  
...  
Keyword(s):  
Inner Cell Mass ◽  
False Negative ◽  
Cell Mass ◽  
Categorical Variables ◽  
P Value ◽  
Sequencing Data ◽  
Preimplantation Genetic Testing ◽  
Exact Test ◽  
Institutional Review ◽  
Wide Range

Abstract Study question What is the effect of varying diagnostic thresholds on the accuracy of Next Generation Sequencing (NGS)-based preimplantation genetic testing for aneuploidies (PGT-A)? Summary answer When single trophectoderm biopsies are tested, the employment of 80% upper threshold increases mosaic calls and false negative aneuploidy results compared to more stringent thresholds. What is known already Trophectoderm (TE) biopsy coupled with NGS-based PGT-A technologies are able to accurately predict Inner Cell Mass’ (ICM) constitution when uniform whole chromosome aneuploidies are considered. However, minor technical and biological inconsistencies in NGS procedures and biopsy specimens can result in subtle variability in analytical results. In this context, the stringency of thresholds employed for diagnostic calls can lead to incorrect classification of uniformly aneuploid embryos into the mosaic category, ultimately affecting PGT-A accuracy. In this study, we evaluated the diagnostic predictivity of different aneuploidy classification criteria by employing blinded analysis of chromosome copy number values (CNV) in multifocal blastocyst biopsies. Study design, size, duration The accuracy of different aneuploidy diagnostic cut-offs was assessed comparing chromosomal CNV in intra-blastocysts multifocal biopsies. Enrolled embryos were donated for research between June and September 2020. The Institutional Review Board at the Near East University approved the study (project: YDU/20l9/70–849). Embryos diagnosed with uniform chromosomal alterations (single or multiple) in their clinical TE biopsy (n = 27) were disaggregated into 5 portions: the ICM and 4 TE biopsies. Overall, 135 specimens were collected and analysed. Participants/materials, setting, methods Twenty-seven donated blastocysts were warmed and disaggregated in TE biopsies and ICM (n = 135 biopsies). PGT-A analysis was performed using Ion ReproSeq PGS kit and Ion S5 sequencer (ThermoFisher). Sequencing data were blindly analysed with Ion-Reporter software. Intra-blastocyst comparison of raw NGS data was performed employing different thresholds commonly used for aneuploidy classification. CNV for each chromosome were reported as aneuploid according to 70% or 80% thresholds. Categorical variables were compared using Fisher’s exact test. Main results and the role of chance In this study, a total of 50 aneuploid patterns in 27 disaggregated embryos were explored. Single TE biopsy results were considered as true positive when they displayed the same alteration detected in the ICM at levels above the 70% or 80% thresholds. Alternatively, alterations detected in the euploid or mosaic range were considered as false negative aneuploidy results. When the 70% threshold was applied, aneuploidy findings were confirmed in 94.5% of TE biopsies analyzed (n = 189/200; 95%CI=90.37–37.22), while 5.5% showed a mosaic profile (50–70%) but uniformly abnormal ICM. Positive (PPV) and negative predictive value (NPV) per chromosome were 100.0% (n = 189/189; 95%CI=98.07–100.00) and 99.5% (n = 2192/2203; 95%CI=99.11–99.75) respectively. When the upper cut-off was experimentally placed at 80% of abnormal cells, a significant decrease (p-value=0.0097) in the percentage of confirmed aneuploid calls was observed (86.5%; n = 173/200; 95%CI=80.97–90.91), resulting in mosaicism overcalling, especially in the high range (50–80%). Less stringent thresholds led to extremely high PPV (100.0%; n = 173/173; 95%CI=97.89–100.00), while NPV decreased to 98.8% (n = 2192/2219; 95%CI=98.30–99.23). Furthermore, no additional true mosaic patterns were identified with the use of wide range thresholds for aneuploidy classification. Limitations, reasons for caution This approach involved the analysis of aneuploidy CNV thresholds at the embryo level and lacked from genotyping-based confirmation analysis. Moreover, aneuploid embryos with known meiotic partial deletion/duplication were not included. Wider implications of the findings: The use of wide thresholds for detecting intermediate chromosomal CNV up to 80% doesn’t improve PGT-A ability to discriminate true mosaic from uniformly aneuploid embryos, lowering overall diagnostic accuracy. Hence, a proportion of the embryos diagnosed as mosaic using wide calling thresholds may actually be uniformly aneuploid and inadvertently transferred. Trial registration number N/A

Simultaneous Measurement of Temperature and Velocity in Turbulent Buoyant Plume by Combined LIF and PIV Technique

2006 ◽  
Author(s):  
Yoshie Watanabe ◽  
Yuji Hashizume ◽  
Nobuyuki Fujisawa
Keyword(s):  
Simultaneous Measurement ◽  
Particle Image ◽  
Fluorescent Dyes ◽  
Buoyant Plume ◽  
Thermal Flow ◽  
Piv Technique ◽  
Image Velocimetry ◽  
Wide Range ◽  
High Temperature Sensitivity ◽  
Surrounding Fluid

An experimental technique for simultaneous measurement of temperature and velocity in a thermal flow is described. This technique is based on the two-color laser-induced fluorescence technique combined with the particle image velocimetry. Illumination is provided from Nd:YAG laser and the fluorescent dyes are chosen as Rhodamine B and Fluorescent Sodium, which combination allows the accurate velocity measurement in a wide range of flow velocity and high temperature sensitivity in temperature measurement. The measurement of temperature and velocity in turbulent buoyant plume is carried out by this method, and the structure of the plume is studied in connection with the entrainment of surrounding fluid at the interface.

scholarly journals Discussing the Efficacy and Safety of Covid-19 Vaccine Available in India- A Mini Review

2021 ◽  
Vol 23 (11) ◽  
pp. 330-343
Author(s):  
Yogendra Shrestha ◽  
◽  
Jeet Bahadur Moktan ◽  
Renukaradhya Chitti ◽  
Shiv Kumar Yadav ◽  
...  
Keyword(s):  
Disease Transmission ◽  
Neutralizing Antibodies ◽  
False Negative ◽  
Emergency Situation ◽  
Epidemiological Studies ◽  
Self Awareness ◽  
Negative Results ◽  
Wide Range ◽  
The Government ◽  
Restricted Use

Background: Many variants detected after Wuhan-Hu-1 reference which were able to develop the resistance against the neutralizing antibodies induced by vaccine and may cause false negative results in diagnostic test. Novel variant B1.617 was detected in India and the Covid-19 cases hiked to its maximum; forcing the government towards approving a new vaccine for restricted use in emergency situation to cover a maximum population. Aims: This review looks at the efficacy, safety, and economical aspects of vaccines that have been authorized in India. Materials and methods: Wide-ranging assessment and analysis of accessible resources on online database. Results: The rAd26-s & rAd5-s demonstrate high efficacy as well as safety, followed by BBV152 and AZD1222. Various combinations of the vaccines with different platforms or vectors may induce wide range of immunity than a specific one. As per economical aspect, AZD1222 is more economical than the other two currently approved in India. Conclusion: There is a lack of clear end point to measure efficacy of the vaccine so the epidemiological studies with huge number of populations is required which may predict the perfect endpoint for efficacy measurement. Until then, inoculation with locally accessible vaccines and self-awareness about disease transmission prevention are the main options for reducing fatalities, protecting the health-care system, and eventually disease control.

scholarly journals Fish Allergy Around the World—Precise Diagnosis to Facilitate Patient Management

2021 ◽  
Vol 2 ◽  
Author(s):  
Tanja Kalic ◽  
Christian Radauer ◽  
Andreas L. Lopata ◽  
Heimo Breiteneder ◽  
Christine Hafner
Keyword(s):  
Fish Species ◽  
False Negative ◽  
Management Approach ◽  
Fish Allergy ◽  
Wide Range ◽  
Precise Diagnosis ◽  
Diagnostic Approaches ◽  
Geographic Regions

The accurate and precise diagnosis of IgE-mediated fish allergy is one of the biggest challenges in allergy diagnostics. A wide range of fish species that belong to evolutionary distant classes are consumed globally. Moreover, each fish species may contain multiple isoforms of a given allergen that often differ in their allergenicity. Recent studies indicated that the cross-reactivity between different fish species is limited in some cases and depends on the evolutionary conservation of the involved allergens. Fish allergens belong to several protein families with different levels of stability to food processing. Additionally, different preparation methods may contribute to specific sensitization patterns to specific fish species and allergens in different geographic regions. Here, we review the challenges and opportunities for improved diagnostic approaches to fish allergy. Current diagnostic shortcomings include the absence of important region-specific fish species in commercial in vitro and in vivo tests as well as the lack of their standardization as has been recently demonstrated for skin prick test solutions. These diagnostic shortcomings may compromise patients' safety by missing some of the relevant species and yielding false negative test results. In contrast, the avoidance of all fish as a common management approach is usually not necessary as many patients may be only sensitized to specific species and allergens. Although food challenges remain the gold standard, other diagnostic approaches are investigated such as the basophil activation test. In the context of molecular allergy diagnosis, we discuss the usefulness of single allergens and raw and heated fish extracts. Recent developments such as allergen microarrays offer the possibility to simultaneously quantify serum IgE specific to multiple allergens and allergen sources. Such multiplex platforms may be used in the future to design diagnostic allergen panels covering evolutionary distant fish species and allergens relevant for particular geographic regions.

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