Detection of mutant k-ras sequences in the urine of cancer patients.

DNA fragments from apoptotic cells crossing the renal barrier retain their matrix functions, which allows PCR identification of mutant sequences in excreted DNA. We investigated the possibility of detecting k-ras mutations in urinary DNA of tumor patients (colon cancer). In some patients with k-ras codon 12 mutations in tumor cell DNA the same changes were detected in the urinary DNA.

Immunochemical study of chromatin non-histone proteins. I. Production of antibodies against rat thymus and liver chromatin; analysis of tissue specificity and intranuclear distribution of immunogenic proteins.

Rabbit antibodies against rat thymus and liver chromatin are obtained. Antithymus IgG are found to interact only with homologous chromatin, while antiliver IgG interact with both liver and thymus chromatin. After preincubation of antiliver IgG with thymus chromatin the antibodies interact with homologous chromatin only.

Chromatin regions, released by endogenous nucleases, are enriched in immunogenic tissue-specific proteins.

Localization of immunogenic tissue-specific proteins in chromatin regions, hypersensitive to endogenous nucleases, has been studied using rabbit antibodies against rat thymus chromatin. It is shown that the first 1-2,5% of the chromatin (calculating on DNA), released by Mg2+-, Mn2+- and Ca2+/Mg2+-dependent nuclear endonucleases are drastically enriched in tissue-specific antigenic determinants. The released chromatin fractions are found to contain a heterogeneous set of nonhistone proteins and are deficient in histones.