A field littered with failures sees few companies brave enough to try again. A big market awaits medtech start-ups that find a successful way to end the need for autografts and allografts for soft-tissue repair.

The dealmaking column is a survey of recent transactions, including strategic alliances, mergers & acquisitions, and financings, in the life sciences industries. Deals are listed by the following industry sectors: in vitro diagnostics, pharmaceuticals, medical devices, and research/analytical instrumentation and reagents. All transactions are excerpted from Elsevier's Strategic Transactions database, providing comprehensive transaction coverage from 1991 to the present.

Unlike for other tissues and organs in the body, no good cell culture model of the liver exists. This difficulty has hampered the discovery of therapeutics for a wide variety of liver diseases-hepatitis, cancer, and cirrhosis, for example-but Hepaticus Inc. is planning to change this: the firm has devised a way to model human liver cell functionality using immunocompetent rats.

A group of drug discovery companies believes it has found a way to use scientific discoveries about the genetics of aging to develop novel drugs for specific diseases. These companies begin with insights from animal models of longevity and long-lived human populations, which they hope will help them discover new targets for age-related diseases. Several companies have rallied around calorie restriction, an intervention known to increase lifespan in laboratory animals, and are characterizing genetic and phenotypic changes associated with calorie restriction. Others believe they have found key genes that regulate aging, and hope to use this knowledge to develop drugs for such age-related as diseases as cardiovascular disease, stroke, cancer, and diabetes. The challenges for companies will be to validate mechanisms implicated in aging, and then link them to specific diseases. However, the diseases of aging are some of the toughest drug development categories; they're often progressive diseases that develop over the course of years, and proving that drugs slow down disease progression or prevent onset involves tough endpoints.