FIG. 8.
The determination of the proportion of brain- and serum-derived sequences in serum and brain tissue from patient 1 and 2 (Pt 1 and Pt 2). In addition, in patient 2 lymph node was also studied. One microgram of RNA extracted from medulla oblongata (patient 1) and cerebellum (patient 2) or RNA corresponding to 100 μl of serum was subjected to 20 cycles of RT-PCR, after which the product was serially diluted 1:10 and 1 μl was amplified for another 35 cycles with primers specific for the serum (S)- or brain (B)-derived strain. As seen, in brain tissue the approximate ratio of serum- to brain-derived strains was 1:102 to 1:103, while in serum the brain-derived virus was present at a level 3 to 5 logs lower than that of the major serum-derived virus. In the lymph node in patient 2 the ratio between the two strands was approximately 3 logs. Leftmost lane on each gel, 1-kb molecular ladder (Gibco/BRL).