Abstract: The present invention relates to an immunoactive composition of matter having the general formula AB(T) where AB is an antigen, growth factor or other material which binds to receptor sites on epithelial target cells, notably choroid plexus cells, and T is a moiety which affects the activity of the target cell, for example a toxin or medicament, and which is attached, notably by one or chemical linkages, to the moiety AB. The immunoactive material selectively attaches to the epithelial cells and the moiety T then is absorbed by those cells, thus reducing the risk of acting on other cells. The invention also provides a method of treating epithelial cells, notably the choroid plexus cells so as to regulate the production of CSF from those cells in the treatment of hydrocephalus, by administering the immunoactive material by injection or infusion into the CSF circulation system so as to localise the administration and action of the immunoactive material.

Abstract: The present invention relates to a method and apparatus which provides proactive guidance to a surgeon for guiding the tip of a surgical instrument along a previously defined optimum path within the body of a mammal to a tumour or other target within the body. This path is subdivided into a plurality of sections extending from one intermediate point to another and an image is formed on the exposed surface of the body of the mammal upon which the surgeon is operating. The image is focused below the exposed surface and at the next intermediate point to be traversed along the path. The image provides the surgeon with vector information as to where he should direct the tip of the instrument. The image is preferably three or more overlapping dots of light from lasers which are directed at the intermediate point by motorised mountings under the control of a computer, the splay of the dots of light giving the surgeon the vector information.