Originally created 11/16/00


Love is blind?

Some men who take Viagra may have an eye-opening experience that has nothing to do with sex.

Eye doctors have found that the popular impotence drug also can have profound optical effects in a small number of men. While most of these effects are temporary and harmless - causing peculiar changes in color perception - doctors meeting in Dallas recently described a handful of men who suffered what are essentially small strokes in their eyes. The strokes permanently damaged their optic nerves, causing some loss of vision.

Doctors don't yet have evidence that the strokes were caused by Viagra, but in three of five cases documented so far, "this came on after the first or second time they ever took the medication," said Dr. Robert Egan of the Casey Eye Institute in Portland, Ore., who was one of the researchers. And each time, the optical strokes occurred within an hour or two of taking the drug.

Rhyme and reason

If a statement rhymes, then its meaning must be true. Or could it be that you are swayed by the way words are played?

Scientists studying the perception of sayings have found that rhyming injects credibility, even when it doesn't change the meaning. For example, "haste makes waste" may be seen as a more accurate statement than "haste makes inefficiency."

To study the role of rhyme in reason, researchers from Lafayette College in Easton, Pa., administered questionnaires to 100 undergraduates. The volunteers were asked to assign scores of accuracy to lists of statements. The students didn't know that the researchers were studying rhyme.

The test contained phrases with similar meanings. "What sobriety conceals, alcohol reveals," appeared on the list, as did "What sobriety conceals, alcohol unmasks." For another part of the test, students were cautioned about the influence of rhyme. The boldface instructions warned the students to judge the statement's claims, regardless of the poetic flavor of the words.

Writing recently in the journal Psychological Science, the researchers reported that the students assigned a higher score of accuracy to rhyming phrases. However, when cautioned about this influence, the accuracy ratings fell.

The scientists point out that orators have long sensed the power of rhyme. Lawyer Johnnie Cochran, after all, entreated O.J. Simpson jurors with the phrase "If it doesn't fit, you must acquit!" The researchers wrote, "We wonder how persuasive the jury might have found this proposition had Mr. Cochran proclaimed, `If the gloves don't fit, you must find him not guilty!"'

Dangerous stowaways

Billions of invaders enter U.S. harbors each year, escaping notice from even the best-trained border guards.

That's because these stowaways are invisible. An analysis of ships entering Chesapeake Bay found that each vessel's ballast imports an average of about 30 billion viruses per gallon of water and about 3 billion bacteria. Among the microbes taking a free ride: the bacterium that causes cholera,researchers from the University of Maryland and other institutions reported recently in the journal Nature.

Ships have taken on ballast water for stability since the 19th century; they now carry about 79 million tons of it into U.S. ports each year, the researchers reported. Crews typically release the water when they reach their destination.

Many ecologists have worried about ships carrying foreign species of animals such as mussels and jellyfish into habitats with no natural predators. But little is known about the role of ballast water in spreading germs that cause human disease.

Genetic puberty

Scientists have found a gene that may control major life transitions in many animals. In people, researchers are speculating, the gene may control events like the budding of teeth or puberty.

In the latest issue of the journal Nature, an international team of scientists announce that they have found the tiny gene - only 21 letters of DNA code in length - in people, worms, flies, fish, mollusks and sea urchins.

The gene, known as let-7, was originally discovered in a microscopic roundworm known as Caenorhabiditis elegans. These worms go through several larval stages before reaching maturity. The let-7 gene helps the worm shift from the last larval stage to adulthood.

In people, the scientists reported, the let-7 gene is active in the brain, heart, kidney, liver and many other organs. Although more research is needed, scientists speculate that the gene may also help people mature.

Most genes serve as blueprints for bulky molecules called proteins that carry out the majority of cells' inner workings. The let-7 gene is different. It produces a small molecule of a chemical called RNA, but no protein is ever made.


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