[Isolation, identification and electrophoretic properties of DNA excreted by human lymphocytes].
It was shown that the buoyant density of DNA isolated from lymphocyte incubation media as well as from blood plasma of healthy patients and patients with chronic lympholeukemia (CLL) using the SDS-phenol method with subsequent ultracentrifugation in a cesium trifluoroacetate density gradient is 1.59-1.60 and 1.60-1.63 g/ml, respectively. Using electrophoresis in 0.6% agarose gel, it was found that the DNA excreted by lymphocytes from healthy patients and CLL patients is a high molecular weight fraction comprising 21,000 nucleotide pairs. This DNA fragment contains 90-95% of [3H]thymidine used for the labeling of DNA excreted by lymphocytes from healthy patients and patients with CLL. No traces of [3H]thymidine were found in the middle part of the agarose gel containing the diffuse material bound to ethidium bromide.