HEALTH

Corning Begins Tender Offer for Damon: The deal, valued at about $575 million, covers all outstanding common shares of health care laboratory company Damon Corp. Damon said a week ago that Corning’s proposal to acquire it for $23 a share was superior to a previously announced $16-a-share agreement with National Health Laboratories Inc. La Jolla-based National Health said Wednesday that it dropped its bid. Damon shares closed at $22.625 on the New York Stock Exchange, up 12.5 cents. Corning said the tender offer requires a minimum of 8.9 million Damon shares, or 51%, conditioned on expiration of the regulatory antitrust waiting period, and expires Aug. 3.