containing the passengers). When the vector/gene combination gets into your tumor cells, it inserts 
itself into the cell's genetic material (chromosomes) and tells the tumor cells to begin making thymidine 
kinase (an enzyme). We will also attach to the vector vehicle a bacterial gene which we think is 
harmless: this gene serves to mark the location of the TK gene in your body. When we give you 
Cytovene, the tumor cells containing the TK gene make harmful substances within themselves that 
cause the tumor cells to die. We do not expect normal brain cells to be injured because the vector/gene 
combination is attracted only to rapidly growing cells. Normal cells are not rapidly growing, but tumor 
cells are and are therefore targets for the vector/gene combination. 
Pretreatment Evaluation 
If you decide to participate in this study, you will have a complete neurological and physical examination, 
blood and urine tests to determine your overall physical health. The blood tests will also include a test 
for HIV (aids) virus and women of childbearing age will have a pregnancy test. Patients with HIV and 
pregnant women will not be eligible for further study. In addition, appropriate x-rays and brain scans 
will be done before you begin the study. 
Treatment Phase 
This phase can be divided into three components. 
Surgery: In the operating room following administration of general anesthesia, a craniotomy (direct 
surgery on the brain) will be performed. The brain tumor will be removed to the extent that is safely 
possible to do. Since it is always impossible to completely remove a recurrent malignant brain tumor, 
the remaining tumor and the brain immediately surrounding the tumor will be injected with the vector 
producing cells during the operation. You will receive various drugs that are used routinely in 
neurosurgery to prevent convulsions and brain swelling. These drugs are given to almost all patients 
who undergo brain tumor surgery. At the termination of surgery a small tube will be placed from under 
the scalp to the tumor bed (Ommaya reservoir). 
Seven days after surgery additional vector producing cells will be injected into the area of the remaining 
tumor. This will be done through the Ommaya reservoir and is performed by the neurosurgical staff in 
the clinic. There is no need for anesthesia during this procedure. 
Fourteen days after surgery Cytovene infusions will be started. Cytovene will be administered into a 
vein over a one hour period. The drug will be given two times a day for fourteen days. You will have a 
brain scan before, during and after Cytovene therapy. 
Recombinant DNA Research, Volume 17 
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