Word: plastic
(lookup in dictionary)
(lookup stats)
Dates: all
Sort By: most recent first
(reverse)
...ball valve is rougher on blood cells than nature's leaflet valves, so surgeons at the University of Wisconsin have developed butterfly valves of Teflon that come closer to the original in design. The demands on the plastic in such valves are tremendous: the leaflets must bend back and forth 40 million times a year. But so far, 39 patients have had them installed as replacements for aortic or mitral valves, and they are still working after as long as 20 months...
Filters & Glues. Artificial kidneys now in use are as big as a washing machine or an entire laundry, but medical engineers are making them ever smaller; they hope eventually to devise one that can actually be put inside the body. A hopeful lead comes from a plastic called polyvinyl pyrrolidone, now widely used as the setting agent in women's hair sprays. PVP membranes pass chemicals between the blood and the cleansing water of the artificial kidney about three times as fast as the cellophane membranes now used. PVP has another advantage for an implantable kidney: like Silastic...
Screw-In Cornea. Ironically, the earliest attempt to use a primitive plastic involved one of the most intricate organs in the body. It was an 1853 attempt to replace the cornea of the eye, and it failed. Then the technique of human corneal transplants was developed, and the urgency of finding a plastic seemed to diminish. But human transplants do not stay clear in all cases. An imaginative ophthalmic surgeon, Dr. William Stone Jr., working first in Boston, then in Los Angeles, has devised a corrective corneal implant of plastic...
Many eye surgeons have learned to correct detachment of the retina by putting a plastic girdle around the eyeball and squeezing it back into shape. And Dr. Stone has implanted plastic tubes in the eyes of glaucoma patients at Massachusetts Eye and Ear Infirmary to remove the accumulation of fluid that causes high pressure inside the eyeball-and eventually blindness...
...replace relatively insensitive tissues and those that are easy to get at, plastic surgeons have a wide choice of materials. They carve Silastic sponge to the shape of a human ear and cover it with skin grafts. For men who have undergone castration because of cancer, there are artificial testicles of the same or a similar material. Artificial breasts are now made of a soft silicone-rubber sack that holds a silicone gel, and they have a backing of Dacron for attachment to the chest wall...