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Arctic precipitation is predicted to increase this century. Records of past precipitation seasonality provide baselines for a mechanistic understanding of the dynamics controlling Arctic precipitation. We present an approach to reconstruct Arctic precipitation seasonality using stable hydrogen isotopes (δ2H) of aquatic plant waxes in neighboring lakes with contrasting water residence times and present a case study of this approach in two lakes on western Greenland. Residence time calculations suggest that growing season lake water δ2H in one lake reflects summer precipitation δ2H, while the other reflects amount‐weighted annual precipitation δ2H and evaporative enrichment. Aquatic plant wax δ2H in the "summer lake" is relatively constant throughout the Holocene, perhaps reflecting competing effects of local summer warmth and increased distal moisture transport due to a strengthened latitudinal temperature gradient. In contrast, aquatic plant wax δ2H in the "mean annual lake" is 100‰ 2H depleted from 6 to 4 ka relative to the beginning and end of the record. Because there are relatively minor changes in summer precipitation δ2H, we interpret the 100‰ 2H depletion in mean annual precipitation to reflect an increase in winter precipitation amount, likely accompanied by changes in winter precipitation δ2H and decreased evaporative enrichment. Thus, unlike the "summer lake," the "mean annual lake" records changes in winter precipitation. This dual‐lake approach may be applied to reconstruct past changes in precipitation seasonality at sites with strong precipitation isotope seasonality and minimal lake water evaporative enrichment. Key Points: Neighboring lakes with contrasting residence times may be used to reconstruct precipitation isotopes from different seasonsWestern Greenland had wetter winters in the middle Holocene due to increased oceanic heat transport and decreased winter sea iceHolocene summer precipitation isotopes on western Greenland were relatively constant suggesting consistent summer moisture source [ABSTRACT FROM AUTHOR]

Radioimmunotherapy offers an exciting new therapeutic modality for patients with relapsed non-Hodgkin's lymphoma; however, considerable debate exists regarding the optimal dose and administration schedule for radioimmunoconjugates. Myelosuppression has been the dose-limiting toxicity of most clinical trials employing radiolabeled antibodies, and this complication has generated both high-dose and low-dose treatment strategies. 'Low-dose' strategies are nonmyeloablative and rely upon repetitive infusions to effectively eradicate tumor masses. Trials incorporating low-dose radioimmunotherapy have documented high response rates, though the durability of these responses remains unclear. The most encouraging nonmyeloablative studies have documented objective responses in 70%-80% of patients, complete responses in 30%-50% of patients, minimal toxicity, and a median response duration of 12 months. In contrast, high-dose trials performed in conjunction with autologous hematopoietic stem cell transplantation have demonstrated objective responses in 95% of patients, complete responses in 85% of patients, with a progression-free survival of 62% and an overall survival of 93% with a median follow-up of two years. Toxicities are considerably higher than those reported with nonmyeloablative regimens, but are modest compared to conventional marrow transplant conditioning regimens incorporating total body irradiation (TBI). Ongoing trials integrating high-dose radioimmuotherapy with high-dose chemotherapy in an autologous transplantation setting are testing the hypothesis that targeted radiotherapy plus chemotherapy will provide increased efficacy and diminished toxicity as compared to nonspecific external beam TBI-containing regimens.

Radioimmunotherapy offers an exciting new therapeutic modality for patients with recurrent hematologic malignancies and solid tumors resistant to conventional chemotherapy. In this review, a brief overview of tumor radiobiology as well as various obstacles to treatment is presented. Early radiolabeled antibody trials documented myelosuppression as the dose-limiting toxicity. Ongoing trials in solid tumors and hematologic malignancies are testing the hypothesis that myeloablative doses of radiation in conjunction with hematopoietic stem cell rescue will improve long-term survival. For solid tumors, there are many barriers to achieving this goal. The most encouraging trials in metastatic breast cancer have documented significant symptomatic relief and a 50% partial response in patients. In contrast, trials involving hematologic malignancies have produced more impressive results. With a median follow-up of 33 months, 67% of patients with recurrent acute myelogenous leukemia or myelodysplasia treated with radiolabeled antibodies, total-body irradiation, and high-dose chemotherapy remain disease free. Alone, myeloablative doses of radioimmunotherapy have documented a 41% complete response in patients with Hodgkin's disease. Seattle trials with recurrent non-Hodgkin's lymphoma have demonstrated objective responses in 90% of patients, complete responses in 85% of patients, a progression-free survival of 62%, and an overall survival of 93% with a median follow-up of 2 years.