Shares of Intuitive Surgical ( ISRG) were among the best-performing health-related stocks Wednesday, rising 27% after the surgical robotics company posted results that blew away third-quarter forecasts. The company earned $20.7 million, or 55 cents a share, on sales of $60.9 million. Analysts polled by Thomson First Call expected earnings of 29 cents a share and sales of $50 million. A year earlier, the company earned $6.1 million, or 17 cents a share, on sales of $35.5 million. During the most recent period, the company sold 30 of its da Vinci surgical systems, up from 18 a year ago. System revenue surged to $33.6 million from $19 million last year. Shares were recently trading up $19.47 to $91.46. Kensey Nash ( KNSY) fell 11% after the medical device company posted first-quarter results that disappointed Wall Street and forecast a weak second quarter. The company reported a loss of $182,752, or 2 cents a share, on total revenue of $12.7 million. On a pro forma basis, which excludes a depreciation charge and other one-time items, the company reported earnings of $1.2 million, or 10 cents a share. Analysts projected earnings of 19 cents a share and total revenue of $15.5 million. A year earlier, the company earned $3.2 million, or 26 cents a share, on sales of $15.1 million. Looking ahead, Kensey Nash forecast second-quarter pro forma earnings of 11 cents to 13 cents a share, below analysts' mean estimate of 25 cents. The company sees total sales of $13.3 million to $14.1 million, short of Wall Street's expectation of $16.6 million. Shares traded down $2.96 to $24.24. Tanox ( TNOX) rose 12% after the company said its HIV inhibitor performed well in a Phase II trial. The study showed that TNX-355, in combination with an optimized background therapy, demonstrated a statistically significant reduction in viral load when compared to a placebo. "TNX-355 has the potential to provide considerable advantages over the current standard-of-care for HIV patients," the company said, "and we look forward to working with the FDA on next steps toward bring this therapy to a growing number of patients who have limited treatment alternatives." The company, which is still conducting Phase II testing, said it hopes to begin a Phase III study of the drug during 2006. Shares were up $1.50 to $13.99.