Abstract: A novel anti-polyethylene glycol monoclonal antibody and its preparation are disclosed. Such an antibody can be used for determining polyethylene glycol concentration in vitro or accelerating the clearance of a polyethylene glycol containing compound from the blood circulation in the human body thereby reducing the toxicity associated with the polyethylene glycol containing conjugate. The antibody is particularly useful in cancer therapy where the therapeutic agent is selectively delivered to the tumor by increasing the tumor/blood ratio of the polyethylene glycol containing compound.

Abstract: A robust method of stabilizing a diode laser frequency to an atomic transition is provided. The method employs Zeeman shift to generate an anti-symmetric signal about a Doppler-broadened atomic resonance, and, therefore, offers a large recapture range as well as high stability. The frequency of a 780 nm diode laser, stabilized to such a signal in Rb, drifts less than 0.5 MHz.sub.pk-pk (one part in 10.sup.9) in thirty-eight hours. This tunable frequency lock may be inexpensively constructed, requires little laser power, rarely loses lock, and may be extended to other wavelengths by using different atomic species.