Word: viruses
(lookup in dictionary)
(lookup stats)
Dates: during 1940-1949
Sort By: most recent first
(reverse)
...United States now stands at the wrong phase of two distinct influenza cycles. An influenza pandemic, which recurs every twenty to thirty years, has not been visited upon the world since 1918, when it killed twenty-one million people of whom half a million were Americans. The pandemic virus has been due to strike again since 1937. Less powerful viruses, the more common influenza "A" or "B", tend to run in five or six year cycles. Both are set for a re-appearance, since neither has been detected in epidemic form since before...
Scientists are sure that infantile paralysis is caused by a virus. They have long known where to look for it-in the brain and spinal cord. But isolation of the elusive virus itself has led researchers on one of the most expensive searches in medical history. Last week two Stanford University scientists, backed by the National Foundation for Infantile Paralysis, thought they had finally come near the end of the trail...
Stanford Chemists Hubert S. Loring and C. E. Schwerdt had pondered a strange puzzle. Like other polio virus hunters, they had ground up and sifted the brains and spinal cords of nobody knows how many infected rats and monkeys. They had prepared virulent extracts, capable of transmitting the disease. But when they refined their material further, its virulence somehow disappeared...
...refining process kill the virus? Loring and Schwerdt thought lowering the temperature might keep the virus alive. As part of a long process, they made an extract from the brains and spinal cords of polio-infected cotton rats, froze it. Then, letting it start to thaw, they whirled their material in an ultra-high-speed centrifuge (60,000 revolutions per minute) to separate its protein, and with chemicals refined the protein further. Eventually they isolated a particle less than two-billionths of an inch in diameter. The protein particle proved to be 80 to 95% pure virus; a billionth...
Next step: to inactivate the virus (by ultraviolet radiation or chemicals) and produce a concentrated vaccine that might prevent polio...