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Results are presented from a statewide survey that measured annual 222Rn concentrations in over 2000 single-family, owner-occupied homes in New York state. The participants were selected by a random-digit-dialing telephone interview approach developed by Mitofsky-Waksberg which allows inferences to be made from the sample to the statewide population. After completing a telephone questionnaire and agreeing to have their homes monitored, eligible households were mailed alpha-track detectors with instructions to place one detector in the main living area for 2 mo (during the winter heating season), a second in the main living area for 1 y, and a third in the basement (if applicable) for 1 y. The statewide median concentration for the heating-season, living-area readings was 31.6 Bq m-3, with a median of 24.0 Bq m-3 for the annual living-area readings and 51.8 for the annual basement readings. For the state, approximately 95% of the living-area concentrations and 86% of the basement concentrations were below 148 Bq m-3 (4 pCi L-1). In addition, only 1.4% of the readings in the basement were above 740 Bq m-3 (20 pCi L-1).

The size and kinetics of the cell population of six advanced human solid tumors were analyzed following the continuous infusion of H3-TDR for a period of 6 to 21 days. By using the labelling indices of the cells in interphase and mitosis, and the rate of label incorporation, it was found the only 10 to 40% of the tumor cell population was replicating at any given time. Fifty-five percent to 85% of the remaining cell mass eventually entered into cycle at least once. Anywhere from 5% to 40% of the cell population remained arrested in G2 or G0 in individual cases during the period of observation. The significant size of the "resting" cell compartment is undoubtedly one explanation for the relative insensitivity of advanced adult solid tumors to current cell cycle-oriented therapeutic regimens.

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