Leukaemia cytogenetics / H. Jackson Woodliff.

  • Woodliff, H. Jackson.
Date:
1971
Catalogue details

Licence: Attribution-NonCommercial 4.0 International (CC BY-NC 4.0)

Credit: Leukaemia cytogenetics / H. Jackson Woodliff. Source: Wellcome Collection.

    33/168 (page 17)
    METHODS 17 Automated Scanning of Chromosomes Survey of a larger number of metaphases is time consuming and an automatic system is required to scan metaphases and to produce karyotypes giving statistics on chromosome lengths, breadths, shapes and areas; several systems are being developed (Gilbert, 1966; Ledley et al., 1966; Ledley and Ruddle, 1966). The FID AC and BUGS YS system developed by Dr. Ledley and his colleagues at the National Biomedical Research Foundation, Silver Springs, Maryland, makes use of photographic negatives of metaphases; the film is then placed in a flying-pot scanner (FIDAC —Film Input to Digital Automatic Computer) and the informa¬ tion fed into a computer programmed to recognize, count and classify the chromosomes. The time needed is about 20 seconds, compared with an estimated one to three hours for conventional karyotyping. The term BUGSYS is given to the picture processing and measuring system, which used a collection of programmable pointers considered as a family of bugs (hence BUGSYS bug system); it is compatible with FORTRAN II language. A dis¬ advantage of this system is that it does not eliminate photography and the equipment is too expensive to be considered for most centres. Possibly a centre to which negatives could be sent would be appropriate for each country. Its advantage is that it has developed to the stage of being useful ; work on a similar system is being carried out in London {British Medical Journal, 1968). Another system being developed in Philadelphia scans the slides for suitable metaphases and feeds chromosome measurements directly into a computer (Mendelsohn et al, 1966, 1969). This has not yet reached the stage of being commercially available but has considerable potentialities. It is based on optical information obtained from a densitometric measurement by a special purpose cytophotometer linked to a computer (CYDAC). Electron Microscopy Electron microscopy of chromosomes is time consuming and costly; however, recent advances in this kind of technique are promising. These methods provide pictures of chromosomes at a greater magnification than can be obtained by a light microscope and can also reveal electron density and profile type pictures (Schultz et al, 1949; Christenhuss et al, 1967; Neurath et al., 1967; Neurath, 1968; Lampert et al., 1969). It is hoped that this