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Approaches for Identification and Validation of Antimicrobial Compounds of Plant Origin: A Long Way from the Field to the Market
Published in Mahendra Rai, Chistiane M. Feitosa, Eco-Friendly Biobased Products Used in Microbial Diseases, 2022
Lívia Maria Batista Vilela, Carlos André dos Santos-Silva, Ricardo Salas Roldan-Filho, Pollyanna Michelle da Silva, Marx de Oliveira Lima, José Rafael da Silva Araújo, Wilson Dias de Oliveira, Suyane de Deus e Melo, Madson Allan de Luna Aragão, Thiago Henrique Napoleão, Patrícia Maria Guedes Paiva, Ana Christina Brasileiro-Vidal, Ana Maria Benko-Iseppon
In addition to determining susceptibility, the growth kinetics of the microorganism in the presence of the antimicrobial agent may also be evaluated. Microbial growth involves the multiplication and population growth of a cell culture, in addition to the increase in biomass produced by such microorganisms. Several indirect methods to measure microbial biomass are being used, based on the measurement of some metabolic activity or some specific component of the biomass (Lekha and Lonsane 1994). The evaluation of the growth rate and the generation time allows to evaluate the concentration of the cells during the incubation time and to verify the cell growth in function of possible alterations of the environmental conditions, as the presence of an antimicrobial agent. Growth must be quantified by the spectrophotometric method of turbidimetry or nephelometry. In these methods, cell growth is monitored according to the turbidity of the solution. The result obtained is expressed in terms of absorbance as a function of time. The most used wavelength for turbidimetry/nephelometry readings is found in the red region (~ 660 nm), as wavelengths in this range generate less light scattering compared to shorter wavelengths (Abdallah et al. 2014; Kogawa et al. 2021).
Translating the Medical Record
Published in Walter F. Stanaszek, Mary J. Stanaszek, Robert J. Holt, Steven Strauss, Understanding Medical Terms, 2020
Walter F. Stanaszek, Mary J. Stanaszek, Robert J. Holt, Steven Strauss
Immunodiagnostic or serodiagnostic tests study antigen-antibody reactions for diagnosis of infectious disease, autoimmune disorders, neoplastic disease, and immune allergies. They also test for blood grouping and typing, tissue and graft transplant matching, and cellular immunology. Serologic testing, also termed microbial immunology, evaluates antigens of bacteria, viruses, fungi, and parasites. Terms related to these procedures include polymerase chain reaction (PCR), rate nephelometry, flow cytometry, complement fixation (CF), and enzyme immunoassay (EIA). Serologic tests for syphilis (STS) include fluorescent treponemal antibody absorption (FTA-ABS), rapid plasma reagin (RPR), Venereal Disease Research Laboratory (VDRL), and microhemagglutination assay for Treponema pallidum antibodies (MHA-TP).
Diagnostic applications of immunology
Published in Gabriel Virella, Medical Immunology, 2019
Ajay Grover, Virginia Litwin, Gabriel Virella
Immunonephelometry is a preferred alternative for gel-based precipitation assays, as this technique is more sensitive and can be automated. Immunonephelometry is also based on the formation of antigen-antibody complexes and makes use of antibody and/or antigen calibrators. The analyte of interest is measured by light dispersion (nephelometry).
Attenuated glutamine synthetase as a selection marker in CHO cells to efficiently isolate highly productive stable cells for the production of antibodies and other biologics
Published in mAbs, 2019
Pao-Chun Lin, Kah Fai Chan, Irene A. Kiess, Joselyn Tan, Wahyu Shahreel, Sze-Yue Wong, Zhiwei Song
Suspension CHO-GS−/- cells were cultured in the 50/50 medium consisting of 1:1 ratio mix of HyClone PF-CHO Multi-powder system (Cat: SH30333.01, GE Healthcare) and CD CHO medium (Cat: 10743029, Thermo Fisher Scientific) and incubated in 37°C, 8% CO2 shaking incubator. The 50/50 medium was supplemented with 0.05% Pluronic F-68 acid (Cat: 24040032, Thermo Fisher Scientific) and 6 mM L-glutamine (Cat: 25030–081, Thermo Fisher Scientific). Ten million cells were transfected with 5 μg of different DNA constructs via electroporation (SG Cell line 4D-Nucleofector® X Kit) (Cat: V4XC-3024, LONZA). Two days after transfection, the transfected cells were placed under L-glutamine removal selection until their viability recovered to more than 90%. GSwt stable pools were further subjected to 25 µM MSX (Cat: M5379, Sigma-Aldrich) selection. Batch culture was then performed on the recovered pools to measure the levels of IgG (antibody GA101) production using the nephelometer (Siemens Healthcare). The nephelometry method is a liquid-based immunoassay based on measuring the amount of scattered light generated by the immunocomplexed particles in the sample. It is a sensitive and reliable method for IgG measurement, often used in clinical settings, and allows the screening of a large number of samples in a short period of time. The IgG assay reagent (Cat: OSAS15, Siemens Healthcare), which is the IgG-specific reagent, was routinely used calibrated to ensure accuracy.
Diagnostic utility of kappa free light chains in multiple sclerosis
Published in Expert Review of Molecular Diagnostics, 2019
Batia Kaplan, Esther Ganelin-Cohen, Sizilia Golderman, Avi Livneh
Although development and use of nephelometric FLC assay have opened new avenues in the studies of intrathecal immune response and offer a new approach in the diagnosis of MS, the pitfalls of this assay are now well recognized. In fact, antibodies used in the nephelometric FLC assay recognize only a limited number of epitopes (situated between heavy and light chains of intact immunoglobulins), and these antibodies may preferentially detect FLC dimers over monomers [16]. In addition, the two major commercial antibodies used in this assay, i.e. Freelite (The Binding Site Group Ltd., Birmingham, UK) and N Latex FLC (Siemens Healthcare Diagnostics Gmbh, Marburg, Germany) may provide different results for the same sample. According to a recent study [17], the observed quantitative discrepancies may arise be due to different immunoreactivities of these antibodies against FLC monomers and dimers, especially with respect to lambda FLC. Since the FLC levels measured using nephelometry represent the total sum of monomeric and dimeric FLC, certain degree of inaccuracy is inevitable in this test. These limitations of the FLC assay cannot be ignored in view of the CSF studies employing Western blot-based techniques [18–20], which showed that the abnormal immune response in MS involves not only increased FLC levels, but also changes in the FLC monomer/dimer ratios.
Proenkephalin and risk of developing chronic kidney disease: the Prevention of Renal and Vascular End-stage Disease study
Published in Biomarkers, 2018
Lyanne M. Kieneker, Oliver Hartmann, Andreas Bergmann, Rudolf A. de Boer, Ron T. Gansevoort, Michel M. Joosten, Joachim Struck, Stephan J. L. Bakker
Urine electrolytes were directly analyzed according to standard laboratory procedures. Concentrations of total cholesterol, high-density lipoprotein (HDL) cholesterol, triglycerides and glucose were determined as previously described (Verhave et al. 2004, Oterdoom et al. 2009). Measurement of serum creatinine was performed by an isotope dilution mass spectrometry (IDMS) traceable enzymatic method on a Roche Modular analyzer using reagents and calibrators from Roche (Roche Diagnostics, Mannheim, Germany), with intra- and interassay coefficients of variation of 0.9% and 2.9%, respectively. Serum cystatin C concentrations were measured by Gentian Cystatin C Immunoassay (Gentian AS, Moss, Norway) on a Modular analyzer (Roche Diagnostics). Cystatin C was calibrated directly using the standard supplied by the manufacturer (traceable to the International Federation of Clinical Chemistry Working Group for Standardization of Serum Cystatin C) (Grubb et al. 2010). The intra- and interassay coefficients of variation were <4.1% and <3.3%, respectively. UAC was measured by nephelometry with a threshold of 2.3 mg/L, and intra- and interassay coefficients of variation of 2.2% and 2.6%, respectively (Dade Behring Diagnostic, Marburg, Germany).