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An abstract of the study "Evaluation of Elevated Uranium Bioassay Samples," by J. S. Bland and W. Gaul is presented.

An abstract of the article "A Comparison of Prediction Equations for the Isotopic Distribution of Enriched Uranium and the Impact on the Determination of Decommissioning Criteria," by A. J. Nardi is presented.

An abstract of the article "The Use of Parametric Statistics to Determine the Number of Samples Needed to Release a Site," by W. C. Gaul and W. G. Jansen is presented.

A Markov chain in conjunction with an electronic spreadsheet is used to generate the buildup and decay patterns of radon progeny in a procedure involving only multiplication and addition. Markov chains are highly suitable for calculations of this type. Because the Markov matrix may not be readily available, and because some health physicists may not be familiar with this procedure, we give the values of a Markov matrix and demonstrate how it can be used to produce a Markov chain describing the buildup and decay of radon progeny.

Hemodynamic effects of dopamine and intravenous nitroglycerin alone, and in combination, were studied in 27 patients with severe left ventricular failure. Dopamine alone increased cardiac index from 1.8 to 2.5 l/min/m2 but also increased wedge pressure from 24 to 30 mm Hg and heart rate from 88 to 101 beats/min. Arterial oxygen saturation fell from 92% to 87% (p less than .001). Nitroglycerin alone had a lesser effect on cardiac index (1.8 to 2.2 l/min/m2) but decreased wedge pressure from 26 to 16 mm Hg and heart rate from 91 to 86 beats/min. Arterial oxygen saturation fell from 91% to 90% (NS). Combined dopamine and nitroglycerin administration resulted in optimal hemodynamics, with cardiac index of 2.9 l/min/m2, wedge pressure of 17 mm Hg, and heart rate of 96 beats/min. Arterial oxygen saturation remained low at 88% in spite of the reduction in left ventricular filling pressure, which probably reflects increased intrapulmonary right-to-left shunting coupled with increased pulmonary blood flow. These results suggest that the combination of dopamine with intravenous nitroglycerin should be considered for patients with severe left ventricular dysfunction who require temporary pharmacologic support.