Polymerase chain reaction test

There are various methods for detecting Mycoplasma contamination of cell culture. A sensitive polymerase chain reaction test with broad specificity for Mycoplasma species is our method of choice (8). There are several products available for the eradication of Mycoplasma species from cell lines. The effectiveness of the treatment will depend on the cells and involves trail and error. This is because some cell lines are very sensitive to the chemicals used to eradicate Mycoplasma and may become static or die during treatment. 

The simplest and most reliable means of diagnosis is a wet-mount examination of the vaginal discharge. Trichomoniasis is confirmed if characteristic pear-shaped, flagellating organisms are observed. Newer diagnostic tests such as monoclonal antibody or DNA probe techniques, as well as polymerase chain reaction tests are highly sensitive and specific. 

Immunosuppressed radiation victims may also be at risk for reactivation of cytomegalovirus (CMV) and Pneumocystis carinii pneumonia. In a limited casualty situation, if resources are available, clinicians should obtain CMV serology. In addition, patients should have a sensitive assay (antigen assessment or polymerase chain reaction test) every 2 weeks for 30 days postexposure, while those with documented previous CMV exposure should have the assay repeated until 100 days postexposure (2). Patients developing lymphopenia should have a CD4 cell count considered at 30 days postexposure. Those with a CD4 count below 0.2000 x 10 cells L" are at risk for Pneumocystis carinii pneumonia. Physicians should withhold trimethoprim-suha prophylaxis until the leukocyte count is above 3.0 x 10 cells L" or until the absolute neutrophil count is above 1.5 x 10 cells L . Atovaquone, dap-sone and aerosohzed pentamidine are alternative prophylactic agents. Patients should continue prophylactic treatment until the CD4 count reaches or exceeds 0.2000 X 10 cells L, which may occur over several months (2). 

The task of integrating laboratory automation begins with the laboratory workstation. In general, a clinical laboratory workstation is usually devoted to a defined task (e.g., performing chemistry profiles, complete blood counts, hormone testing, polymerase chain reaction testing, and urinalysis) and contains appropriate laboratory instrumenta-... 

Hamilton MS, Jackson MA, Abel. Clinical utility of polymerase chain reaction testing for enteroviral meningitis, Pediatr Infect Dis J 1999 18 533-8. 

Diagnostic tests for amebiasis include stool for ova, antigen detection, or polymerase chain reaction (PCR) testing. 

Recent innovations for detecting malaria include DNA or RNA probes by polymerase chain reaction (PCR). These, however, are not widely available for clinical use. A rapid dipstick test (ParaSight F, Becton-Dickinson, Cockeyville, MD) reportedly has a sensitivity of 88% and a specificity of 97%, which is comparable to microscopy. However, ParaSight F can give false-positive results with rheumatoid factor thus microscopy remains the optimal test. 

Format 1 SBH can be used to uncover polymorphism and mutations in a particular gene. The sample amplicons of genomic DNA of a test individual and the amplicons for the control DNA for the gene of interest with a known reference sequence are both prepared by polymerase chain reaction (PCR). A subset of probes that is complementary... 

The viral load test quantifies viremia by measuring the amount of viral RNA. There are several methods used for determining the amount of HIV RNA reverse transcriptase-coupled polymerase chain reaction, branched DNA, and nucleic acid sequence-based assay. Each assay has its own lower limit of sensitivity, and results can vary from one assay method to the other therefore, it is recommended that the same assay method be used consistently within patients. 

Rapid antigen and point-of-care tests, direct fluorescence antibody test, and the reverse-transcription polymerase chain reaction assay may be used for rapid detection of virus. 

J.R. Uhl, C.A. Bell, L.M. Sloan, M.J. Espy, T.F. Smith, J.E. Rosenblatt and F.R. Cockerill, Application of rapid-cycle real-time polymerase chain reaction for the detection of microbial pathogens the Mayo-Roche rapid anthrax test, Mayo Clin. Proc., 77 (2002) 673-680. 

The Polymerase Chain Reaction. In the past, a major drawback of hybridization assays was their need for relatively large amounts of sample DNA to compensate for their low sensitivity. This problem has been surmounted in recent years by the development of powerful enzymatic techniques that can exponentially replicate specific DNA sequences in the test tube. With these techniques it is now possible to analyze vanishingly small samples that initially contain fewer than 10 copies of the sequence of interest. The new methods take advantage of the chemical properties of nucleic acids and of highly specialized enzymes that can repair and replicate DNA in vitro. 

Figure 2 Cytokine gene expression in immunopotentiating reconstituted influenza virosomes (IRIV) stimulated peripheral blood mononuclear cells (PBMC). PBMC were cultured in the presence or absence of IRIV. On days 1 and 2, culture cells were harvested and total cellular RNA was extracted and reverse transcribed. The cDNAs thus obtained were tested in real time polymerase chain reaction assays in the presence of primers specific for the indicated cytokine genes. Source From Refs. 6 and 9.

Confirmation of positive ELISA for HIV infection (more specific test for anti-HIV antibodies) Polymerase chain reaction (PCR) ... 

Genetic methods Polymerase chain reaction (PCR) and its variants, e.g., multiplex PCR, are widely used for C. botulinum detection. Reverse-transcriptase PCR is recommended as an alternative to biological tests using mice (McGrath et al., 2000). 

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