Robust but weak winter atmospheric circulation response to future Arctic sea ice loss.

The possibility that Arctic sea ice loss weakens mid-latitude westerlies, promoting more severe cold winters, has sparked more than a decade of scientific debate, with apparent support from observations but inconclusive modelling evidence. Here we show that sixteen models contributing to the Polar Amplification Model Intercomparison Project simulate a weakening of mid-latitude westerlies in response to projected Arctic sea ice loss. We develop an emergent constraint based on eddy feedback, which is 1.2 to 3 times too weak in the models, suggesting that the real-world weakening lies towards the higher end of the model simulations. Still, the modelled response to Arctic sea ice loss is weak: the North Atlantic Oscillation response is similar in magnitude and offsets the projected response to increased greenhouse gases, but would only account for around 10% of variations in individual years. We further find that relationships between Arctic sea ice and atmospheric circulation have weakened recently in observations and are no longer inconsistent with those in models.

Mitoxantrone, fluorouracil, and high-dose leucovorin: an effective, well-tolerated regimen for metastatic breast cancer.

Between September 1988 and August 1990, we treated 35 women with metastatic breast cancer with a novel regimen containing mitoxantrone, fluorouracil (5-FU), and high-dose leucovorin. This regimen was designed to take full advantage of the favorable toxicity profiles of these agents while maintaining a high level of activity. All patients had received previous chemotherapy (adjuvant only, 15 patients; at least one metastatic regimen, 20 patients). Seven patients had received previous doxorubicin, but none within 6 months of study entry. Of 31 assessable patients, 20 (65%) had objective responses (two complete, 18 partial), with a median response duration of 6 months (range, 3 to 16+ months). Four patients with bone metastases (abnormal bone scan only) and pain were not considered assessable by strict response criteria; two of these patients had sustained symptomatic relief for 6 and 8 months, respectively. Myelosuppression was the most frequent toxicity but was mild in most patients; only four hospitalizations for fever and neutropenia were required (2% of courses). No severe thrombocytopenia occurred and no RBC transfusions were required. Alopecia, mucositis, and nausea/vomiting were uncommon and were not severe in any patient. The combination of mitoxantrone, 5-FU, and high-dose leucovorin is well tolerated and active as a first- or second-line treatment for metastatic breast cancer. Comparison with other standard regimens for breast cancer is indicated.

Recognition of Mycoplasma arthritidis membrane antigens by rats and rabbits: comparison by immunoblotting and radioimmunoprecipitation.

Sera from rats convalescing from infection with Mycoplasma arthritidis were tested for their ability to react with M. arthritidis membrane antigens by immunoblotting and radioimmunoprecipitation. The absence of metabolism-inhibition (MI) antibody activity in these sera suggested that rats might fail to recognize those membrane antigens involved in eliciting MI antibodies therefore rabbit antisera, which are strongly MI positive for M. arthritidis, were used for comparison. Antigenic recognition patterns of M. arthritidis surface and membrane antigens were not identical for rats and rabbits. The most striking and reproducible difference was the failure of rats to produce IgG antibodies against a surface antigen migrating in the 47,000-50,000 molecular weight range on SDS-polyacrylamide gels. However, rats recognized at least 2 antigens which we had previously shown to be "MI antigens", therefore the inability to express MI antibodies probably cannot be explained by their inability to recognize M. arthritidis "MI antigens".