Abstract
In an attempt to bring the suspended particles of an aqueous spinal cord suspension containing rabies or poliomyelitis virus into more intimate contact with inactivating agents for vaccine production trials a “solution” of the cord was made with the aid of urea. The effect of urea in strong concentration on these viruses proved interesting. As first recorded by Spiro 1 and in more detail by Ramsden 2 urea in aqueous solution has a remarkable ability to “dissolve” proteins. When spinal cord of the rabbit or monkey, moist with saline, is placed in a mortar and urea crystals added the cord on trituration quickly passes into an opaque syrupy “solution” containing innumerable lipid droplets in suspension. In this manner a 50% cord “solution” containing from 30% to saturation with urea is easily obtained.
Rabies Virus. Typical results are presented in Table I. The fixed rabies virus usually killed within 6–11 days after intracerebral inoculation. The non-urea treated virus suspension was a 20% concentration of cord and brain in saline. The urea treated preparation contained 50% of cord-brain and about 40% of urea. Rabbits 3 and 4 were injected intracerebrally within an hour after the preparation of the cord “solution”. They were given a second injection of 0.2 cc. each of a urea-treated preparation 10 days after the first ones with no ill effects. Rabbits 5 and 6 were given injections of 0.1 cc. each of the non-urea-treated preparation 3 weeks after the first injections. Both of them died within a week. Rabbit No. 7 was given a weekly “vaccination” by a 1.0 cc. subcutaneous injection of the 50% urea-treated rabies cord preparation for 6 weeks and then inoculated intracerebrally
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