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Brushes used to collect samples for cytology. Liquid-based cytology is a method of preparing samples for examination in cytopathology.The sample is collected, normally by a small brush, in the same way as for a conventional smear test, but rather than the smear being transferred directly to a microscope slide, the sample is deposited into a small bottle of preservative liquid.
A molecular-weight size marker, also referred to as a protein ladder, DNA ladder, or RNA ladder, is a set of standards that are used to identify the approximate size of a molecule run on a gel during electrophoresis, using the principle that molecular weight is inversely proportional to migration rate through a gel matrix.
A liquid biopsy, also known as fluid biopsy or fluid phase biopsy, is the sampling and analysis of non-solid biological tissue, primarily blood. [ 1 ] [ 2 ] Like traditional biopsy , this type of technique is mainly used as a diagnostic and monitoring tool for diseases such as cancer , with the added benefit of being largely non-invasive.
Further information about the specimen may be gained by immunohistochemical stains and molecular testing, particularly if the sample is prepared using liquid based cytology. Often "reflex" testing is performed, such as HPV testing on an abnormal pap test or flow cytometry on a lymphoma specimen.
In analytical chemistry, sample preparation (working-up) refers to the ways in which a sample is treated prior to its analyses. Preparation is a very important step in most analytical techniques, because the techniques are often not responsive to the analyte in its in-situ form, or the results are distorted by interfering species .
Picture of an SDS-PAGE. The molecular markers (ladder) are in the left lane. Polyacrylamide gel electrophoresis (PAGE) is a technique widely used in biochemistry, forensic chemistry, genetics, molecular biology and biotechnology to separate biological macromolecules, usually proteins or nucleic acids, according to their electrophoretic mobility ...
The liquid is added to the slide before the addition of the organism and a coverslip is placed over the specimen in the water and stain to help contain it within the field of view. [ 1 ] Fixation , which may itself consist of several steps, aims to preserve the shape of the cells or tissue involved as much as possible.
In a 1966 paper, Watson P. described the first cytocentrifuge, calling it "an apparatus for concentrating cells in suspension onto a microscope slide". [12] The device was sold commercially in the 1970s and in 1983 it was patented by Shandon (now Thermo Scientific). As of 2012, numerous brands of cytocentrifuge exist on the market. [8]