November 17, 1998

Scientists are poised to study meteoroids trailing Comet 55P/Tempel-Tuttle, through whose wake the Earth is about to pass at a point that promises to produce the most spectacular Leonid meteor storm in 33 years; scientists also expect that many Leonid meteors will have been freshly knocked loose from the comet, making them better indications of the comet's composition than fragments that have aged; photos (M)

Reconstruction of weekend's events based on interviews with several participants indicates Pres Clinton called off missile attack on Iraq only minutes before it was set to begin on advice of national security adviser Samuel R Berger; Berger apparently responded to CNN report that Iraqis sent letter to United Nations agreeing to let arms inspectors resume work; Defense Sec William S Cohen apparently opposed delaying attack, holding Iraqi letter was too late and too confused; aides to State Sec Madeleine K Albright, who was en route to Asian economic summit conference, said she wanted attack to proceed; photo (M)

William H Gates, Microsoft Corp chairman, in videotaped deposition shown in court, stubbornly debates meaning of words like 'we' and 'concern'; even 'market share' seems alien to Gates, whose company owns just about all of market in major product categories of personal computer software business; Government uses Gates tape, third deposition shown in antitrust trial, to attack Microsoft's defense that it decided to fold Internet browsing software into its Windows operating system to improve its product (M)

Scientists urge caution on using nicotine replacement products to help smokers quit and on using nicotine to treat a variety of disorders in which it shows promise, including stress, ulcerative colitis, Alzheimer's disease, Parkinson's disease, attention deficit disorder and Tourette's syndrome; agree that replacement nicotine in the form of chewing gum and a skin patch is safer than smoking, but fear these products will be used by smokers far longer than the short period for which they were designed; say value of nicotine in treating other ailments must be weighed against possible side effects, including damage to cells that line blood vessels and airways in the lungs; photo; drawing (M)

Pharmaceutical companies are increasingly enhancing their advertising for prescription drugs in a style more commonly associated with products sold over-the-counter; Competitive Media Reporting, marketing research firm, reports spending on consumer advertising has exploded since Food and Drug Administration in 1997 loosened restraints on on television commercials for prescription drugs; says this type of advertising rose to $100 million this month, almost five times the total only three years ago; demand generated by consumer advertising has raised questions about how such ads are changing practice of medicine; some physicians contend ads artifically stoke demand for most expensive treatments and waste tiime for both patients and doctors; in addition, insurers complain that demand is inflating their pharmaceutical budgets; photo; chart on advertising budgets for certain drugs (Advertising column) (L)