Bioject Medical Technologies wants to give the medical community a shot in the arm. Its Biojector 2000 jet injection system delivers injectable medication without a needle (and thus without needle-associated risks) by using a fine, high-pressure stream that goes through the skin; the injector is powered by CO2   disposable cartridges or tanks. The accompanying vial adapter device allows the Biojector system to be filled without a needle. The company also markets Vitajet, a spring-powered, needle-free self-injection device that has been cleared for administering injections of insulin and Merck Serono's human growth hormones. Investment firm Signet Healthcare Partners and affiliates own one-third of Bioject.