Improved PCR amplification for molecular analysis using DNA from long-term preserved formalin-fixed,paraffin-embedded lung cancer tissue specimens

Archival tissue specimens are valuable resources of materials for molecular biological analyses in retrospective studies, especially for rare diseases or those associated with exposure to uncommon environmental events. Although successful amplification with PCR is essential for analysis of DNA extracted from archival formalin-fixed, paraffin-embedded (FFPE) tissue specimens, we have often encountered problems with poor PCR amplification of target fragments. To overcome this, we examined whether heat treatment in alkaline solution could efficiently restore the PCR template activity of DNA that had already been extracted from FFPE lung cancer tissue specimens. The effect of the heat treatment was assessed by PCR for the TP53 gene and other lung cancer-related gene loci. The heat treatment of DNA samples in borate buffer resulted in successful PCR amplification of DNA fragments ranging from 91 to 152 bp. This technique for restoration of template activity of DNA for PCR amplification is very simple and economical, and requires no special apparatus, so it may be applicable for molecular analysis of DNA samples from FFPE tissue specimens at various laboratories.     

Effects of body position on transient evoked otoacoustic emissions: the clinical perspective Efectos de la posición del cuerpo en las emisiones otoacústicas evocadas por transitorios: la perspectiva clínica

The present study investigated body position effects on transient evoked otoacoustic emission (TEOAE) recordings of clinical significance. Sixty adults (30 males, 30 females) were assessed using the Otodynamics ILO88 Analyzer in three positions (sitting, supine, and side-lying). Results indicated significant positional effects on the TEOAE parameters of A–B difference, noise, whole wave reproducibility, and response levels. These differences included higher noise levels in supine and side-lying positions in comparison to the upright sitting position. Lower whole wave reproducibility measurements, and higher response amplitudes, in the side-lying position compared with supine and seated positions were also observed. No significant effects were evident for signal-to-noise ratio or band reproducibility. Given the lack of significant body position effects on these latter parameters and the infrequent clinical use of the other parameters in isolation, there was no evidence to suggest the future need for major review of current pass/fail criteria or of the standard test protocol.