I The relationship between serum theophylline concentration and daily dose was studied in 45 patients receiving aminophylline orally and in 36 patients receiving it by constant intravenous infusion. 2 Patients were categorized as uncomplicated chronic obstructive pulmonary disease (COPD) or COPD with cor pulmonale (CP). 3 Serum theophylline concentration relative to daily theophylline dose was significantly higher in patients with COPD plus CP than in patients with COPD alone. 4 Total body clearance of theophylline estimated from data obtained during constant intravenous infusion was significantly lower in COPD plus CP than in patients with COPD alone. 5 We conclude that reduced maintenance doses of theophylline are indicated in patients with COPD when complicated with CP.

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Abstract-We consider competition between non-cooperative mobiles over several independent collision multiple-access channels or more generally, over interference channels. A mobile selects one of the channels for transmission; if the same channel is chosen simultaneously by more than a single mobile then a collision occurs and the colliding packets are lost. Policies based on assigning each independent channel to another mobile turn out to constitute efficient equilibria. But they request some synchronization and coordination which may not be possible. We identify other mixed equilibria that do not request synchronization but exhibit innefficiency. Moreover, we show that a Braess type paradox occurs in which the availability of more resources results in poorer performance to all mobiles. We extend the model to investigate the influence of capture phenomena.