location(s) and the number of the lesions. Ganciclovir administration will begin on the 
seventh day after the procedure for 14 days. 
B. Volume and number of injected cells: 
Factors such as tumor size, location, and the preoperative neurological 
condition of the patient will determine the injectable volume. As a rule, the injection of a 
maximal number of vector producer cells in as small a volume as possible will be 
attempted. The final cell concentration will be adjusted to < 1X10 8 cells/ml. 
C. Peri-operative medications: 
1 . Antibiotics: All patients will receive a single dose of IV 2g Ceftriaxone just prior to 
the surgical procedure. 
2. Steroids: All patients will receive dexamethasone at 32 mg/day starting 7 days 
prior to the vector-producer cell injection and treatment will be continued until 
GCV is discontinued. Dexamethasone will then be tapered according to 
individual patient requirement. As experience is gained, the need for high 
dexamethasone dosing may be modified. 
3. Mannitol: Will be administered during the surgical procedure at Ig/Kg and the 
dose repeated TID for 24 hours following the procedure. 
4. Anticonvulsants: Anticonvulsive therapy will be administered according to the 
usual neurosurgical guidelines for such medications. 
5. Analgesics: Pain medications will include Acetominophen 650-1000 mg Q 4 
hours. 
D. The GITKSVNa Retroviral Vector 
GITKSVNa is a retroviral vector derived from the Moloney murine 
leukemia virus (MoMLV). This vector contains a herpes thymidine kinase (HS-tk) gene 
cDNA that is transcribed from the viral LTR and a bacterial neomycin resistance (NeoR) 
gene transcribed from an internal SV40 (simian virus 40) early promoter (LTR-HS-tk-- 
SV--NeoR--LTR) in the G1 vector backbone (Genetic Therapy Inc., Gaithersburg, Md). 
This G1 -based vector has been modified for increased safety by alteration of the gag 
start codon to a stop codon, and by elimination of viral sequences needed for the 
formation of the virus. This has been shown to minimize the potential for helper virus 
Recombinant DNA Research, Volume 15 
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