Medicine: Drug Against a Virus

For the first time, medical researchers have found a drug that cures a disease caused by a true virus. Ophthalmologist Herbert E. Kaufman told a Manhattan symposium on virology last week that he has used the drug in 46 cases of a common infection of the eyes called herpetic keratoconjunctivitis. More than half of Dr. Kaufman’s patients got such prompt benefit that their eyes escaped permanent damage, and in more severe cases the damage was limited.

The disease is the most frequent cause of eyeball-scarring infections in the U.S., and for no known reason it is becoming commoner. Its scars are the main reason for corneal transplants. Its cause is the versatile virus herpes simplex, which usually does no more harm than to touch off annoying fever blisters or canker sores in the mouth, but may cause blindness if it reaches the eyes, or even death if it attacks the brain.

Window in the Eye. Dr. Kaufman decided to try 5-iodo-2´-deoxyuridine (or IDU), a close chemical kin to 5-fluoro-2´-deoxyuridine (or FUDR ), one of the drugs given to House Speaker Sam Rayburn in his last illness. These chemicals were developed in the hope that cancer cells would be fooled into using them instead of normal metabolic building blocks, which they closely resemble. Dr. Kaufman reasoned that cells invaded by viruses might react the same way, and thus be saved from helping the virus to reproduce.

The difficulty in checking a viral infection is to find a chemical that behaves differently in normal and diseased cells, or to find a part of the body in which the chemical acts against the virus without damaging cells. Such a part of the body is the eye. Dr. Kaufman reasoned that since the cornea, a kind of plastic window, has no blood supply, its cells might be more receptive to the effects of the drug. Kaufman’s hunch, tested in rabbits, proved right in humans.

Drops Every Hour. At Massachusetts Eye and Ear Infirmary in Boston, Dr. Kaufman and colleagues dropped IDU into herpes-infected eyes every hour during the day and every two hours at night.

On this rigorous schedule, patients whose corneas were infected only on the outermost layer were healed in an average of three days and had no scars. If the virus had reached a deeper layer, healing took about a day longer.

In cases where the cornea was already scarred and the infection had penetrated its deepest layers to the inner parts of the eye. IDU sometimes could not cure the disease, but still it could be made to help. In a herpes-infected eye, cortisone (which has sometimes been mistakenly tried because it is valuable in many other eye afflictions) often does swift and hideous damage by increasing inflammation. Dr. Kaufman found that a combination of IDU and cortisone in these severe cases promoted healing of the inner part of the eye and minimized damage.

The drug does not attack free virus particles directly. It works by preventing their multiplication after they enter cells. Timing is important: Dr. Kaufman has found that if IDU is given at longer than hourly intervals, it does not work. Whether this first chemical breakthrough against virus infections will lead to others, no one can say. largely because of the unique nature of the cornea. Dr. Kaufman is hopeful but cautious.

To virologists who are used to electron microscope photographs showing viruses like fuzzy tennis balls or tired tadpoles, the models presented by Britain’s Dr. Robert Home last week had an eye-opening clarity that comes from two recent developments in the study of virus structure. Dr. Home, working at the Institute of Animal Physiology in Cambridge, and other British virologists have pioneered virus staining and electronic magnification until they can picture viruses (typically, one twenty-five millionth of an inch long) 500,000 times lifesize. This gave them enough information to make big models.

In sticking rods or spheres (representing protein molecules) around a simulated virus’ nucleic acid core, they hit upon designs and number groups that reminded them of the light, strong geodesic domes designed by U.S. Architect-Engineer Buckminster Fuller. Consulting his books, they found the symmetries of the shapes all matched neatly. The Horne group’s reconstruction of the herpes simplex virus has 162 protein rods. An animal tumor virus has 42. An adenovirus (cause of some respiratory diseases) has 252 spheres making a figure with 20 faces. These are all favorite Fuller numbers, and the keystone of his keystoneless structure.