A Positive Correlation Between IgG2 Antibody Preponderance and Clearance of HSV During Active HSV Infections
P. Mereena Luke, K. R. Dhanya, Didier Rouxel, Nandakumar Kalarikkal, Sabu Thomas in Advanced Studies in Experimental and Clinical Medicine, 2021
The HSV confirmed (PCR positive) samples were classified as age-wise and gender-wise. Similar steps were done for healthy individuals to confirm HSV negativity. For the detection of total IgGs, levels (IgM, IgG) from the above serum samples EIA kits were obtained from ABCAM (Cat. No. ab137982-IgM, ab195215-IgG). For the detection of HSV, specific IgGs levels (IgM, IgG) from the above serum samples EIA kits were procured from CALBIOTECH, USA, and MYBIOSOURCE (USA) (Cat. No. H1M4908, H2M4989, H1G5010, H2G4881). For the detection of IgG subclasses from the above demography, the EIA kits were obtained from Invitrogen-ThermoScientific (Cat. No. 991000). The analysis of immunoglobulins levels on serum samples was performed according to the manufactures instructions. Then the plates were read at 450 nm in an ELISA plate reader. A standard curve was plotted by linear regression analysis using the values of the standard and the values of the unknown samples were calculated from the graph.
Analytical Method Validation
Shein-Chung Chow in Analytical Similarity Assessment in Biosimilar Product Development, 2018
The choice of parameters that will be explored during an assay validation is determined by the intended use as well as by the practical nature of the analytical method. For example, a biochemical assay using a standard curve to establish drug content might require the exploration of all of these parameters if the assay is to be used to determine low as well as high levels of the analyte (such as an assay used to determine drug level in clinical samples or an assay that will be used to measure the content of an unstable analyte). If the assay is used, however, to determine content in a stable preparation, the LOD and LOQ need not be established. On the other hand, an assay for an impurity requires adequate sensitivity to detect and/or quantify the analyte; thus the LOD and LOQ become the primary focus of the validation of an impurity assay.
Use of Computers in Radiotracer Studies
Lelio G. Colombetti in Principles of Radiopharmacology, 2019
A standard curve is always constructed by first determining the mass of target molecules that corresponds to a measured fraction of bound radioactivity. A plot with nanograms of target molecules along the X axis, and fraction of bound radioactivity along the Y axis, then gives a calibration curve that can be used to measure the amount of target molecules in an unknown sample. Several different types of plots are utilized in which different quantities are plotted along the Y axis in an attempt to make the standard curve come out as a straight line. The Y axis may represent the fraction bound, the inverse of the fraction bound, the fraction free, the inverse of the fraction free, or a transformation of the fraction bound (such as the logit), or some other combination. If the standard curve is a straight line, then subsequent analysis is facilitated by fitting a straight line to it by the method of least squares.
Preparation, in vitro and in vivo evaluation of pinocembrin-loaded TPGS modified liposomes with enhanced bioavailability and antihyperglycemic activity
Published in Drug Development and Industrial Pharmacy, 2022
Xinyi Shen, Wanjing Rong, Michael Adu-Frimpong, Qing He, Xiaoxiao Li, Feng Shi, Hao Ji, Elmurat Toreniyazov, Xiaoli Xia, Jian Zhang, Qilong Wang, Jiangnan Yu, Ximing Xu
The orbital vein blood of rats was collected prior to 30 min of water bath at 37 °C, while the serum (100 µL) was collected into 1.5 mL plastic centrifugal tubes after centrifugation, before we accordingly added 100 µL of different concentrations of PCB solution (0.02, 0.05, 0.1, 0.2, 0.5, 1, 2, 5, 10, 25, and 50 µg/mL) and 50 µL (2 µg/mL) of emodin solution (internal standard). Later on, 400 µL of ethyl acetate was added into the mixtures, prior to collection of supernatants into plastic centrifugal tubes after centrifugation. Afterwards, 400 µL of ethyl acetate was again put into the remaining precipitation, before we gathered the supernatants after centrifugation and drying with N2, as well as the addition of methanol (100 µL) for re-dissolution. Later, we determined the peak area of different concentrations of PCB in serum under the established HPLC conditions. The concentration of PCB was taken as the X-axis, while the ratio of the peak area of PCB to the emodin (internal standard) represented the Y-axis. The standard curve of PCB in vivo was established. The linear equation of the standard curve in vivo was as follows: Y = 0.5912X – 0.05574 (R2=0.9998), wherein it was linear in the range of 0.02–50 µg/mL.
Prevalence of SLCO1B1 single nucleotide variations and their association with hypercholesterolaemia in hypercholesterolemic patients in Gauteng, South Africa
Published in Xenobiotica, 2021
Rene de Beer, Kim Outhoff, Alisa Phulukdaree, Prashilla Soma
Briefly, plasma was diluted with Sample Diluent in a 1:50 ratio. Standards were reconstituted and prepared in sample diluent. A total of 50 μl of each sample or standard with known concentration (0 pg/mL, 62.5 pg/ml, 125 pg/ml, 250 pg/ml, 500 pg/ml, 1000 pg/ml, 2000 pg/ml, 4000 pg/ml) was added in duplicate to the appropriate wells in a 96 well plate, after which 50 μl of the antibody cocktail was added to each well. The plate was sealed and incubated for one hour at RT on a plate shaker set to 400 rpm. After incubation, each well was washed with 3 × 350 μl 1 × Wash Buffer PT by aspirating from each well and then dispensing 350 μl 1 × Wash Buffer PT into each well. A total of 100 μl of TMB substrate was added to each well (5 min, RT, 400 rpm). After incubation, 100 μl of Stop Solution was added to each well and the plate was placed back onto the plate shaker for 1 min to ensure thorough mixing. The optical density was measured using a spectrophotometer (Biotek Synergy HT, Software GEN 5.1) at an absorbance 450 nm. A standard curve was constructed, and concentrations of the unknown samples were calculated using the equation derived from the standard curve (y = mx + c).
Novel model predicts diastolic cardiac dysfunction in type 2 diabetes
Published in Annals of Medicine, 2023
Mingyu Hao, Xiaohong Huang, Xueting Liu, Xiaokang Fang, Haiyan Li, Lingbo Lv, Liming Zhou, Tiecheng Guo, Dewen Yan
The calibration curve is the consistency between the frequency of observed results and prediction probability. Research calibration is expressed by following the relationship between the frequency of the effect and the predicted probability. A sensible calibration measure is a likelihood ratio statistic testing the null hypothesis that intercept = 0 and slope = 1. The statistic has a χ2 distribution with 2 degrees of freedom (unreliability U-statistic) [20]. We also evaluated average (E-aver) and maximal errors (E-max) between predictions and observations obtained from a calibration curve. Plotted the calibration curve to assess the calibration of the nomogram, and the nonsignificant test statistics show that the model has been perfectly calibrated [21]. Decision curve analysis (DCA) was used to evaluate the clinical value of the predictive model. Decision curve analysis was conducted to determine the clinical usefulness of the nomogram by quantifying the net benefits at different threshold probabilities in the validation dataset [22].
Related Knowledge Centers
- Bradford Protein Assay
- Chromium
- Coomassie Brilliant Blue
- Reagent
- Analytical Chemistry
- Internal Standard
- Analyte
- Instrumentation
- Sensor
- Photomultiplier Tube