Evaluation of ” Caterina assay”: An Alternative Tool
Evaluation of ” Caterina assay“: An Alternative Tool to the Commercialized Kits Used for Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) Identification
Here we describe the first molecular test developed in the early stage of the pandemic to diagnose the first cases of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection in Sardinian patients in February-March 2020, when diagnostic certified methodology had not yet been adopted by clinical microbiology laboratories. The “Caterina assay” is a SYBR®Green real-time reverse-transcription polymerase chain reaction (rRT-PCR), designed to detect the nucleocapsid phosphoprotein (N) gene that exhibits high discriminative variation RNA sequence among bat and human coronaviruses.
The molecular method was applied to detect SARS-CoV-2 in nasal swabs collected from 2110 suspected cases. The study article describes the first molecular test developed in the early stage of the declared pandemic to identify the coronavirus disease 2019 (COVID-19) in Sardinian patients in February-March 2020, when a diagnostic certified methodology had not yet been adopted by clinical microbiology laboratories.
The assay presented high specificity and sensitivity (with a detection limit ≥50 viral genomes/μL). No false-positives were detected, as confirmed by the comparison with two certified commercial kits. Although other validated molecular methods are currently in use, the Caterina assay still represents a valid and low-cost detection procedure that could be applied in countries with limited economic resources.
Description: Premade ready to use kits will always come in handy. Get your experiment done right form the first try by using a validated kit with perfectly balanced reagents proportions and compatibility and by following a clear protocol.
Description: The OxiSelect ROS Assay Kit is a cell-based assay for measuring hydroxyl, peroxyl, and other reactive oxygen species activity within a cell. The assay employs the cell-permeable fluorogenic probe DCFH-DA, which diffuses into cells and is deacetylcated by cellular esterases into the non-fluorescent DCFH (Figure 1). In the presence of ROS, DCFH is rapidly oxidized to highly fluorescent DCF. Fluorescence is read on a standard fluorometric plate reader.
Description: The OxiSelect ROS Assay Kit is a cell-based assay for measuring hydroxyl, peroxyl, and other reactive oxygen species activity within a cell. The assay employs the cell-permeable fluorogenic probe DCFH-DA, which diffuses into cells and is deacetylcated by cellular esterases into the non-fluorescent DCFH (Figure 1). In the presence of ROS, DCFH is rapidly oxidized to highly fluorescent DCF. Fluorescence is read on a standard fluorometric plate reader.
Description: The OxiSelect Cellular Antioxidant Assay Kit is a cell-based assay for measuring the activity of an exogenous antioxidant compound within adherent cells. Cells are first cultured in a 96-well black fluorescence cell culture plate until confluent. Then the cells are pre-incubated with a cell-permeable DCFH-DA fluorescence probe dye and the bioflavonoid Quercetin, or the antioxidant sample being tested. After a brief incubation, the cells are washed, and the reaction started by adding the Free Radical Initiator. The Free Radical Initiator creates free radicals that convert the probe to highly fluorescent DCF. The Quercetin inhibits the formation of free radicals, and thus DCF formation, in a concentration dependent manner.
Description: The OxiSelect ROS Assay Kit is a cell-based assay for measuring hydroxyl, peroxyl, and other reactive oxygen species activity within a cell. The assay employs the cell-permeable fluorogenic probe DCFH-DA, which diffuses into cells and is deacetylcated by cellular esterases into the non-fluorescent DCFH (Figure 1). In the presence of ROS, DCFH is rapidly oxidized to highly fluorescent DCF. Fluorescence is read on a standard fluorometric plate reader.
OxiSelect In Vitro ROS/RNS Assay Kit (Green Fluorescence)
Description: The OxiSelect In Vitro ROS/RNS Assay provides a sensitive method to detect total reactive oxygen species (ROS) plus reactive nitrogen species (RNS) in a wide variety of sample types. This assay employs a proprietary fluorogenic probe, DCFH-DiOxyQ; the probe is primed with a dequenching reagent to the highly reactive DCFH form. In the presence of ROS and RNS, the DCFH is rapidly oxidized to the highly fluorescent DCF.
OxiSelect In Vitro ROS/RNS Assay Kit (Green Fluorescence)
Description: The OxiSelect In Vitro ROS/RNS Assay provides a sensitive method to detect total reactive oxygen species (ROS) plus reactive nitrogen species (RNS) in a wide variety of sample types. This assay employs a proprietary fluorogenic probe, DCFH-DiOxyQ; the probe is primed with a dequenching reagent to the highly reactive DCFH form. In the presence of ROS and RNS, the DCFH is rapidly oxidized to the highly fluorescent DCF.
Description: A polyclonal antibody against cmk. Recognizes cmk from Escherichia coli. This antibody is Unconjugated. Tested in the following application: ELISA
Description: The OxiSelect In Vitro ROS/RNS Assay provides a sensitive method to detect total reactive oxygen species (ROS) plus reactive nitrogen species (RNS) in a wide variety of sample types. This assay employs a proprietary fluorogenic probe, DCFH-DiOxyQ; the probe is primed with a dequenching reagent to the highly reactive DCFH form. In the presence of ROS and RNS, the DCFH is rapidly oxidized to the highly fluorescent DCF.
Description: Ac-DEVD-CMK is a cell-permeable and irreversible caspase-3 inhibitor [1][2][3]. Apoptosis is a process of programmed cell death that occurs in multicellular organisms.
Description: Ac-DEVD-CMK is a cell-permeable and irreversible caspase-3 inhibitor [1][2][3]. Apoptosis is a process of programmed cell death that occurs in multicellular organisms.
Evaluation of a new semi-automated Hydragel 11 von Willebrand factor multimers assaykit for routine use
Background: Accurate diagnosis and classification of von Willebrand disease (VWD) are essential for optimal management. The von Willebrand factor multimers analysis (VWF:MM) is an integral part of the diagnostic process in the phenotypic classification, especially in discrepant cases. The aim of this study was to evaluate the performance of a new Hydragel 11VWF multimer assay (H11VW).
Methods: Analytical performance characteristics such as repeatability (intra-assay variability, in gel between track variation), reproducibility (inter-assay variability, between gel variation), sensitivity, EQA performance and differences between two commercially available VWF:MM kits (H5VW and H11VW) were analysed in healthy volunteers’ plasmas using in-house prepared reference plasma.
Results: Repeatability and reproducibility results of H11VW demonstrated acceptable and equivalent performance with previously verified H5VW. Participation in EQA was successful. No statistically significant difference was detected between H5VW and H11VW kits for different fractions of multimers: LMWM p=0.807; IMWM p=0.183; HMWM p=0.774.
Conclusions: H11VW demonstrated acceptable analytical performance characteristics. H11VW kit conveniently offers a more significant number of samples on a single gel. H5VW and H11VW kits can be used in daily practice interchangeably.
Developmental validation of VeriFiler™ Plus PCR Amplification Kit: A 6-dye multiplex assay designed for casework samples
The VeriFiler™ Plus PCR Amplification Kit is a 6-dye multiplex assay that simultaneously amplifies a set of 23 autosomal markers (D3S1358, vWA, D16S539, CSF1PO, D6S1043, D8S1179, D21S11, D18S51, D5S818, D2S441, D19S433, FGA, D10S1248, D22S1045, D1S1656, D13S317, D7S820, Penta E, Penta D, TH01, D12S391, D2S1338, and TPOX), a quality indicator system, and two sex-identification markers. Combined, the markers satisfy the requirements of the Chinese National autosomal DNA database as well as expanded CODIS (Combined DNA Index System).
The VeriFiler Plus kit was developed with an improved Master Mix which incorporates the brighter TED™ dye, and accommodates a higher sample loading volume thus allowing for increased sensitivity and enabling maximum information recovery from challenging casework samples including touch, degraded, and inhibited samples.
Here, we report the results of the developmental validation study which followed the SWGDAM (Scientific Working Group on DNA Analysis Methods) guidelines and includes data for PCR-based studies, sensitivity, species specificity, stability, precision, reproducibility and repeatability, concordance, stutter, DNA mixtures, and performance on mock casework samples. The results validate the multiplex design as well as demonstrate the kit’s robustness, reliability, and suitability as an assay for human identification with casework DNA samples.
Performance of Saliva Samples for COVID-19 Diagnosis by Using the Allplex TM 2019-nCoV AssayKit
Background: Although the nasopharyngeal swab (NPS) is the reference sampling method for the detection of SARS-Cov-2, it is not always possible to collect NPS in some patients. Saliva represents an interesting sampling method because it is less invasive and more convenient in patients with nasal or pharyngeal lesions.
Objective: To compare the RT-qPCR test performances of saliva samples with nasal mid-turbinate swab (NMTS) and NPS samples in a cohort of ambulatory patients suspected of having COVID-19.
Study Design: For each of the 112 enrolled patients, NPS, NMTS, and saliva samples were collected and tested for SARS-Cov-2 detection using three different target genes (RdRP, N and E genes) by RT-qPCR.
Results: Among the positive samples (56/112), saliva samples showed a lower percentage of SARS-Cov-2 detection compared to NPS samples, (85.7 vs. 96.4%), while still a lower percentage was observed for NMTS samples (78.6%). In average, saliva samples showed higher Ct values for all tested target genes, compared to those from NPS and NMTS samples.
Conclusions: By using the AllplexTM 2019-nCoV Assay Kit, saliva samples showed lower sensitivity for SARS CoV-2 compared to NPS samples; however, the not detected cases had lower viral burden in NPS samples (CT values >33) representing an interesting alternative sampling method in patients in which it is not possible to take a NPS sample.
Application of Lithium Assaykit LS for quantification of lithium in whole blood and urine
A commercially available kit for the quantitation of lithium, the Lithium Assay kit LS, was originally developed to measure lithium in serum or plasma using a conventional microplate reader. We investigated whether use of the kit could be extended to quantify lithium in whole blood and urine samples collected at autopsy.
The calibration curve for whole blood showed good linearity ranging from 0.5 to 20 µg/mL with a coefficient of determination of 0.998 when samples were pretreated with methanol followed by acetonitrile. Moreover, for urine, we obtained excellent linearity with a coefficient of determination of 0.999 without any pretreatment.
The accuracies and precisions were 106.3-174.7% and 1.9-18.1% for whole blood and 83.3-118.8% and 5.7-33.8% for urine. The values in the lower concentration range (0.5-1 µg/mL) were not satisfactory, whereas those in the higher range (2-20 µg/mL) were acceptable. The Lithium Assay kit LS was successfully applied to the measurement of lithium in whole blood and urine samples collected at autopsies. This method appears to be useful for forensic toxicological investigations because of its simplicity and speed.
Description: Description of target: The FAM FLICATM Capase 1 kit uses a target sequence (YVAD) sandwiched between a green fluorescent label, FAM, and FMK to make a quick and flexible method to analyze active capases in apoptotic cells. These kits measure apoptosis by detecting active caspases in whole, living cells. They don't work by using antibodies or an ELISA. Instead, their methodology is based a unique cell-permeable and non-cytotoxic reagent called Fluorochrome Inhibitor of Caspases. These kits are suitable for cells in suspension, adherent cells, thin tissue sections (but not fixed or paraffin-embedded cells) from many species including mammalian, insect, and yeast. Different cell types, e.g. HeLa, primary neurons, macrophages and lymphocytes have also been successfully studied with these kits. ;Species reactivity: Human;Application: FC, IF;Assay info: ;Sensitivity:
Description: Description of target: The FAM FLICA™ Caspase 3 & 7 kit uses a quick and easy method to analyze active caspases in apoptotic cells.;Species reactivity: ;Application: FC, IF;Assay info: ;Sensitivity:
