~ ® A blood test was developed to measure the amount of cathepsin, a proteolytic enzyme, in serum. The level of enzyme activity appears to be an early indication of cervical cancer in women. The test may be an adjunct to the present Pap smear as a means to screen females for early signs of cancer. @e We have implemented computer-controlled, eight-variable cell sorting on a dual-beam sorter. Utilizing two laser beams and a multivariable pulse~-height analyzer, cells and chromosomes can be analyzed for several components or properties and sorted based on any cambination of the measurements. An important application is the improved resolution of individual chromosome types from human cells, allowing better chromosome purification for biomedical studies. ® A slit scanning flow cytometer has been constructed which allow high speed measurement of the distribution of dye along cells and chromosomes with a spatial resolution of less than lum. Chromosomes and cells can be classified on the basis of their slit scan profiles. The device is especially useful in detecting aberrant cells or chromosames which may occur as a result of mutagen exposure. ® Assignment of human B-, y-, and 6-globin genes to the short arm of chromosome ll by chromosome sorting and DNA restriction enzyme analysis was accomplished, thus demonstrating a new technique based on flow sorting to assign genes to the chromosomes of the human karyotype. @ The composition of histones, the major proteins binding DNA into the subunit structure of chromatin, has been found to be different in heterochromatin and potentially active chromatin. This lends support to the idea that histones and related proteins may regulate the level of genetic activity of chromatin regions by affecting the condensation states of the chromatin.