Polymerase chain reaction samples collection

Helps et al. (2004) slaughtered two female cattle, followed by one male, and then four female cattle and collected swab samples from the split vertebral-column surfaces. Real-time polymerase chain reaction protocols were followed to determine the extent to which tissue from the male carcass accumulated in the splitting saw and was disseminated to subsequent female carcasses. Under simulated abattoir conditions (i.e., washing the saw for 5 s between carcasses and washing the carcasses before collecting samples), these researchers reported that 0.01% of the tissue recovered from the split vertebral-column surface of the final female carcass in the sequence was from the male carcass and that 10% of the tissue remaining in the housing of the saw was from the male carcass. It was concluded from that study that "should a BSE-positive carcass be... 

The importance of detecting the bcr-abl fusion gene product in CML patients after alloHSCT was studied in 346 patients and 634 collected blood samples. A positive polymerase chain reaction (PCR) 3 months or 36 months after transplant did not predict for relapse, but a positive PCR at 6 or 12 months after transplant was highly predictive." With this tool, it may be possible to identify patients who are at high risk for clinical relapse and to treat them with donor lymphocyte infusion or imatinib in an attempt to suppress or eradicate residual disease. 

In forensic cases, DNA samples can be extracted and purified from small specimens of skin, blood, semen, or hair roots collected at the crime scene. DNA that is suitable for analysis even can be obtained from dried stains of semen and blood. The RFLP analysis performed on these samples then is compared to those performed on samples obtained from the suspect. If the RFLP patterns match, it is then beyond reasonable doubt that the suspect was at the crime scene. In practice, several different probes containing different types of repetitious sequences are used in the hybridizations in order to satisfy certain statistical criteria for absolute, positive identification. The use of different restriction enzymes allow for accuracies in positive identifications of greater than one in 100 million. In recent years, polymerase chain reaction (PCR), a method that amplifies DNA, has made it possible for very small amounts of DNA found at crime scenes to be amplified for DNA fingerprinting analysis. Using specific probes to prime DNA polymerase, many copies of the targeted areas of DNA can be synthesized in vitro and subsequently analyzed. 

A thorough history that elicits details of appropriate exposure (eg, laboratories, animals, animal products, or environmental exposure to locations inhabited by potentially infected animals) is the most important diagnostic tool. Brucellosis should also be strongly considered in differential diagnosis of febrile illness if troops have been exposed to a presumed biological attack. Polymerase chain reaction and antibody-based antigen detection systems may demonstrate the presence of the organism in environmental samples collected from the attack area. 

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