The automation of culturing and harvesting of human chromosome specimens.

This paper describes the development of a machine for the automated culturing and harvesting of human chromosome specimens. The machine is capable of handling different preparation methods simultaneously, such as standard blood cell, blast cell and bone marrow cultures, and can be programmed to perform the prophase synchronization techniques. It is composed of a culture tray, centrifuge, mixer, input and output station and a head assembly capable of transporting samples between the various stations and which is equipped with an aspirator needle to suck off the supernatant and fluid dispensers for the dosing of the various chemicals. A microprocessor system controls all hardware functions and schedules the manipulations of all samples thereby preventing, that more than one sample requires servicing at the same time. The samples (up to a maximum of 255) are processed by the machine in small batches of maximal 16, which can be activated at any time according to one of 16 culture procedures. The cytogeneticist can modify these procedures using a simple interpretive language specifying both the types of manipulations, such as centrifugation, addition of chemicals, sucking of supernatant and the minimal and maximal variation in time, which is allowed between two sequential manipulations. Besides the hardware setup and software organization of the machine, the first preliminary results and future prospects for the machine are presented.

A locked, non-rotating, completely embedded, moveable electrode for chronic brain stimulation studies in freely moving, fighting rats.

A light-weight, yet rugged moveable electrode assembly is described for chronic brain stimulation studies in small-brained animals. The assembly can be completely embedded in a smooth, unobtrusive dental cement cap and is therefore suitable for use in fighting experiments, where collisions with partners and cage walls will limit the use of other assemblies. It permits a variable electrode distance penetration of 3 mm in 75 mu-steps by using a separate unlocking turning-key. This design excludes the possibility of inadvertent displacement of the electrode tips by the animal itself. Since the electrode itself does not rotate during displacement, extra damage arising from possible eccentricity is avoided. The assembly has been used in a number of hypothalamic penetrations, demonstrating its usefulness and reliability.