J R Gralow — Page 2 | PubMed Health

PubMed1986

Southern blot analysis of DNA extracted from formalin-fixed pathology specimens.

We have developed a method for the extraction of DNA from formalin-fixed, paraffin-embedded pathology specimens. High-molecular-weight DNA was recovered from well-fixed nonautolyzed samples of viable tissue. DNA recovered from samples exposed to picric acid or mercuric chloride containing fixatives was not intact. Increasing the formalin fixation time decreased the amount of intact DNA available. When these limitations were taken into consideration, the procedure allowed for the removal of degraded and chemically modified DNA from the preparation, and the final product was suitable for quantitative and qualitative analysis by Southern or dot blotting techniques. Digestion with methylation-sensitive restriction endonucleases showed that DNA methylation patterns were not altered after formalin fixation.

DNA↗

PubMed1985

The optimal application of forward and ninety-degree light scatter in flow cytometry for the gating of mononuclear cells.

Peripheral blood mononuclear cells from ten normal donors were labeled with a monoclonal antibody specific for monocytes and analyzed using a fluorescence activated cell sorter (FACS). Forward and 90 degrees light scatter parameters were studied in order to apply optimal computerized gating to identify and exclude monocytes from lymphocyte populations. An average of 9.45% versus 1.22% of cells, within chosen lymphocyte gates established by forward angle and 90 degrees scatter, respectively, were identified as monocytes. In samples from ten donors, the exclusion of monocytes from the lymphocyte population was more efficient using 90 degrees scatter than forward scatter. Simultaneous use of forward and 90 degrees scatter did not significantly improve the ability to accurately exclude monocytes, but did result in a significant increase in the improper exclusion of lymphocytes. Use of 90 degrees scatter alone, forward scatter alone, and forward and 90 degrees scatter simultaneously to identify lymphoid cells resulted in the exclusion of 12, 17, and 23% of lymphocytes from further analysis. The 90 degrees scatter alone appears to be the optimal method to eliminate monocytes electronically from mononuclear cell populations in which lymphocytes are being studied.

Adult↗