A BRIEF OVERVIEW OF COMPARTMENTAL MODELING FOR INTAKE OF PLUTONIUM VIA WOUNDS.

The aim of this study is to present several approaches that have been used to model the behavior of radioactive materials (specifically Pu) in contaminated wounds. We also review some attempts by the health physics community to validate and revise the National Council on Radiation Protection and Measurements (NCRP) 156 biokinetic model for wounds, and present some general recommendations based on the review. Modeling of intake via the wound pathway is complicated because of a large array of wound characteristics (e.g. solubility and chemistry of the material, type and depth of the tissue injury, anatomical location of injury). Moreover, because a majority of the documented wound cases in humans are medically treated (excised or treated with chelation), the data to develop biokinetic models for unperturbed wound exposures are limited. Since the NCRP wound model was largely developed from animal data, it is important to continue to validate and improve the model using human data whenever plausible.

Serum level monitoring of a new slow release theophylline formulation in patients with chronic lung disease.

1 Serum theophylline levels were performed in 26 patients with chronic lung disease receiving rapid release theophylline (125 mg 6 hourly) and 28 patients receiving slow release theophylline (250 mg 12 hourly) under steady state conditions. 2 For rapid release theophylline the mean +/- s.d. serum theophylline levels at 0 and 2 h were 41.0 +/- 21.7 and 52.3 +/- 20.9 mumol l-1 respectively and for slow release theophylline at 0, 4 and 6 h 43.7 +/- 25.5, 50.9 +/- 23.0 and 51.7 +/- 26.4 mumol l-1 respectively. 3 Serum theophylline monitoring with slow release theophylline was performed in 70 patients with chronic lung disease. The initial dose was 250 mg administered 12 hourly. 4 The mean +/- s.d. steady state serum theophylline level achieved was 76.0 +/- 18.8 mumol l-1 and the mean +/- s.d. dose to produce this level was 9.4 +/ 2.3 mg kg-1 day-1. There was no correlation between dosage and serum theophylline level. 5 Sixty percent of patients required a dosage change for stabilization (375 to 1000 mg/day). Seventeen patients reported unwanted effects (nausea or tremor), which either settled quickly or resolved with dosage reduction. 6 Serum theophylline levels were obtained at different dosages in 44 patients and 18 patients demonstrated dose-dependent kinetics. 7 An initial dose of 500 mg/day is recommended and dosage increments should not exceed 125 mg/day with monitoring by serum theophylline levels.