Objective To investigate the relationship between the TRAb-producing cell precursors and different clinical stages of Graves' disease.Methods Peripheral lymphocytes were infected with Epstein-Barr virus,a kind of lymphocyte precursor stimulator,and were stimulated to produce TRAb.Results Of the total wells containing Ig-producing B cell precursors,there were 34.6% and 29.1% from 2 untreated patients,30% from 1 relapsing patient and only 1.3% and 3.8% from 2 healthy controls that secreted TRAb,respectively.As for the wells containing B cell precursors from 2 remission patients with undetectable TRAb in circulation,the percentage (10.7%) of TRAb-containing wells from one was higher than that from the other (5.3%).And the latter had similar percentage of TRAb-positive wells with the controls.The isotype of TRAb in supernatants of our EBV-transformed B lymphocytes was predominantly IgM.Conclusion The frequencies of TRAb-specific precursors were different at three distinct clinical stages of the disease.

To lay a foundation for the type selection of the ambulance helicopter. The type selection was explored from the aspects of platform selection, rescue environment and service requirements, analyzing the rescue in the helicopter and the tendency of the ambulance helicopter in foreign countries and China. The types of the am-bulance helicopter were determined as the specific and modified ambulances, with the considerations such as operation environment, flight performance, cabin structure, onboard equipment, cabin configuration, fixation device and protection. Specific ambulance helicopter is supposed to be based on small- or mediate-sized platform, while the modi-fied ambulance helicopter is supposed to be based on large or heavy platform.