Radioactive Information and Courses from MediaLab, Inc.

Minute-size fractions achieved in two-dimensional electrophoresis, IEF and PAGE with SDS, and bands from electrophoresis of nucleic acids are detected differently than protein electrophoresis fractions. Labeled polypeptide probes are used to detect these proteins; labeled single-stranded nucleic acid fragments are used for the detection of nucleic acids. Each probe is made with a label designed to generate a detectable signal. The label is bound to a probe and a system is created such that the signal is visualized when the probe is bound to the target.The most common labels are radioactive isotopes and fluorescence dyes. Chemiluminescence and color or ultraviolet absorbance are also used.

Detection techniques can vary in both direct and amplified methodologies and can include labeling either the probe or the target molecule of interest:Chemiluminescence: Release of light energy at the end of a chemical reaction that is detected by a luminometer. Uses a label such as acridinium ester. Electrophoresis: movement in a matrix such as a gel that is caused by an electrical field.Enzyme: Uses enzyme and substrate principles to label the appropriate target or probe. Can be combined with fluorescence or dyes for detection.Fluorescence: Molecules that emit light at a longer wavelength when excited at a shorter wavelength. Detection techniques include fluorescent staining of nucleic acids as well as fluorescent labeled probes that are measured in a fluorometer or with fluorescent polarization.Radioactivity: Uses a labeling technique where the radioactive label is then measured in a scintillation counter. The earliest assays utilized radioactive decay.

A “dirty bomb” is a crude method for spreading radiation over a substantial area. It does not create a nuclear blast. It is made by packing dynamite or some other conventional explosive with virtually any type of radioactive material. When the explosive is detonated, it spews the radioactive material over the surrounding area.

The white diamond at the bottom of the NFPA symbol is the special hazard section. If the chemical reacts with water, a strike-out W (W) will appear in this section. OX means the chemical is an oxidizer. COR means the chemical is corrosive. The radioactivity symbol indicates that the chemical is radioactive.

The US Department of Transportation (DOT) classifies hazardous materials according to the risks that they pose. There are nine hazard classes: Class 1: Explosives Class 2: Gases Class 3: Flammable liquids Class 4: Flammable solids Class 5: Oxidizers/organic peroxides Class 6: Toxic and infectious substances Class 7: Radioactive material Class 8: Corrosives Class 9: Miscellaneous hazardous materials Within class 6 are two divisions: Division 6.1- poisonous material Division 6.2- infectious substanceA division 6.2 infectious substance is defined as a material known or reasonably expected to contain a pathogen. A pathogen is a microorganism or other agent (e.g., a prion) that can cause disease in humans or animals. The regulations that govern packaging and shipping a class 9, miscellaneous hazardous material, may also need to be reviewed by those who package and ship laboratory specimens. Dry ice is a class 9 hazardous material and, if used, requires special packaging, and specific labeling and marking on the outer package.