The recovery and analysis of mitochondrial DNA from exploded pipe bombs.

Improvised explosive devices (IEDs) represent one of the most common modes of arbitrarily injuring or killing human beings. Because of the heat generated by, and destruction to, an IED postconflagration, most methods for identifying who assembled the device are ineffective. In the research presented, steel pipe bombs were mock-assembled by volunteers, and the bombs detonated under controlled conditions. The resultant shrapnel was collected and swabbed for residual cellular material. Mitochondrial DNA profiles were generated and compared blind to the pool of individuals who assembled the bombs. Assemblers were correctly identified 50% of the time, while another 19% could be placed into a group of three individuals with shared haplotypes. Only one bomb was assigned incorrectly. In some instances a contaminating profile (mixture) was also observed. Taken together, the results speak to the extreme sensitivity the methods have for identifying those who assemble IEDs, along with precautions needed when collecting and processing such evidence.

Detection of programmed cell death in cells exposed to genotoxic agents using a caspase activation assay.

Many environmental toxins cause DNA damage. Cells that have sustained significant DNA damage must attempt to repair the damage prior to replication, in which aberrant base incorporation can result in an irreversible mutation. If a cell cannot repair the damage, however, it may commit suicide through a genetically regulated programmed cell death (PCD) pathway. Crucial to the ultimate execution of PCD is a family of cysteine proteases called caspases. Activation of these enzymes occurs late in the PCD pathway, when a cell can no longer avoid cell death, but earlier than other PCD markers, such as morphological changes or DNA fragmentation. This protocol details a method for using fluorochrome-conjugated caspase inhibitors for the detection of activated caspases in intact cells using fluorescent microscopy.