Absence of herpesvirus DNA by polymerase chain reaction in ocular fluids obtained from immunocompetent patients.

Objective: To assess the prevalence of herpesvirus DNA in ocular fluids obtained from healthy patients undergoing vitreoretinal surgery.

Background: Polymerase chain reaction (PCR) has been used to detect herpesvirus DNA in patients with acute retinal necrosis and cytomegalovirus retinitis. Little is known regarding the prevalence of detectable herpesvirus DNA in ocular fluids collected from healthy seropositive patients with no clinical evidence of viral retinitis.

Detection of circulating epithelial cells after surgery for benign breast disease.

Background: Cytokeratins are predominantly expressed in epithelial cells and their malignant counterparts. Ultrasensitive methods for cytokeratin messenger RNAs (mRNAs) can detect rare circulating tumor cells consistent with hematogenous dissemination in epithelial-derived malignancies, including breast carcinomas. Intraoperative tumor-cell shedding may contribute to this process; this hypothesis is based on the assumption that only tumor cells can be mobilized during surgical manipulation.

Specimen stability for DNA-based diagnostic testing.

The use of molecular diagnostic testing is increasing in the clinical setting; therefore, data regarding DNA stability in clinical specimens are essential for correct test performance and interpretation. This study was designed to determine DNA stability in peripheral blood and solid tissue under different storage conditions. DNA quality and yield were assayed by spectrophotometric absorbance, gel electrophoresis, and suitability for Southern hybridization and polymerase chain reaction (PCR), the most widely employed clinical DNA analyses.

Inhibition of PCR by aqueous and vitreous fluids.

The detection of viral nucleic acids in intraocular fluids and tissues by PCR has become increasingly important in clinical ophthalmology. While much attention has been directed toward minimizing false-positive reactions resulting from specimen contamination or amplicor carryover, relatively little attention has been given to the causes of false-negative PCRs. This report describes a PCR inhibitor in normal aqueous and vitreous fluids that can produce false-negative PCR results.