Polymerase chain reaction viral

The plaque assay is desirable because it is very sensitive and only detects infectious viral particles. However, there are viral agents which cannot be supported by cell lines. In these cases other methods must be used. The polymerase chain reaction (PGR), which amplifies DNA or RNA from viral agents, can be used to detect the presence and quantity of viral agents. The amount of RNA or DNA target in the initial sample can be determined by competitive PGR where the quantity of amplified product is compared to a control PGR product where the initial amount of target is known. Quantification is also possible by an end-point dilution method similar to that used to determine a tissue culture infections dose. PGR methods can be very sensitive however. 

Hepatitis D infection requires the presence of HBV for HDV viral replication. Measuring HDV RNA levels in the serum by polymerase chain reaction (PCR) confirms the presence of... 

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. 

Komminoth, P., Long, A. A., Ray, R., and Wolfe, H. J. (1992) In situ polymerase chain reaction detection of viral DNA, single copy genes and gene rearrangements in cell suspensions and cytospins. Diag. Mol. Pathol. 1, 85-97. 

Drut, R. M Day, S., Drut, R., andMeisner, L. (1994) Demonstration of Epstein-Barr viral DNA in paraffin-embedded tissues of Burkitt s lymphoma from Argentina using the polymerase chain reaction and in situ hybridization. Fed. Pathol. 14,101-109. 

HCV and HIV-1). The bDNA assay is being much employed for the quantification of messenger RNA. Moreover, for the detection of viral and pathogenic disorders based on alkahne-phosphatase-sensitive dioxetanes, several assay methods are available these include the Polymerase-Chain-Reaction (PCR) amphfication, probe ligation, strand-displacement amplification and the ligase chain reaction. ... 

Viral detection assays based on infectivity suffer from significant variability, which necessitates the use of statistical evaluation. Polymerase chain reaction-based assays are currently being developed and validated for viral clearance. With PCR assays, there is a potential to distinguish between inactivation and physical removal, perform mass balance studies, evaluate more than one vims at a time for a given process step, reduce the time for completing clearance studies, and accurately quantitate the amount of vims bound to such surfaces as chromatography resins. Table 5 compares the assay precision between an infectivity assay and a quantitative PCR assay. 

Polymerase chain reaction (PCR) techniques can be used to diagnose meningitis caused by M meningitidis, S. pneumoniae, and H. influenzaetype b (Hib). PCR is considered to be highly sensitive and specific. PCR testing of the CSF is the preferred method of diagnosing most viral meningitis infections. 

Although not typically used, laboratory tests are available to help diagnose HSK in equivocal cases. One of the most reliable and festest tests is the Herpchek , which is an enzyme immimoassay test that yields results in 1 day. Additional laboratory tests include viral culture microbio-logic studies, enzyme-linked virus inducible system, and polymerase chain reaction detection. 

Several groups have found no evidence of persistence of measles virus in the tissues of patients with Crohn s disease with a very sensitive test (polymerase chain reaction) (97-100). Furthermore, no viral genomic sequences of measles, mumps, and rubella viruses were found in intestinal specimens (100). The results of lizuka and colleagues (98,101) were particularly interesting—they used the same monoclonal antibody in their immunohistochemical studies that Wakefield and colleagues had used. The antigen recognized could be a measles virus protein, but they... 

Haga Y, Funakoshi O, Kuroe K, Kanazawa K, Nakajima H, Saito H, Murata Y, Munakata A, Yoshida Y. Absence of measles viral genomic sequence in intestinal tissues from Crohn s disease by nested polymerase chain reaction. Gut 1996 38(2) 211-15. 

A 19-month-old girl was immunized against Varicella at 15 months of age and later developed zoster infection (18). Viral cultures from various lesions isolated Varicella zoster virus. The Oka vaccine strain was revealed by polymerase chain reaction. 

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