To evaluate the role of glucagon in insulin-mediated glucose metabolism, we studied four men and four women, ranging in age from 30–73 yr (mean ± SEM, 54 ± 5) who had undergone complete pancreatic resection for cancer or chronic pancreatitis 16–58 mo previously. The patients had undetectable C-peptide levels and established lack of biologically active 3500 mol wt glucagon. Euglycemic insulin clamp studies were performed with a 40 mU · m−2 · min−1 insulin infusion in the basal, post-absorptive, insulin-withdrawn state, before and during the last 3 h of a 72-h glucagon replacement-dose infusion (1.25 ng · kg−1 · min−1). In four patients, hepatic glucose production was determined by a primed-constant infusion of 3-[3H]glucose. Monocyte insulin-binding studies, pre- and postglucagon, were performed in all patients. The 72-h glucagon infusion, resulting in mean plasma glucagon levels of 124 ± 7 pg/ml, caused a significant rise in the mean plasma glucose level (249 ± 8 versus 170 ± 13 mg/dl preglucagon) and a sixfold increase in mean 24-h glucose excretion. Both with and without glucagon, euglycemic hyperinsulinemia achieved identical and complete suppression of hepatic glucose production. The mean glucose utilization rate (4.70 ± 0.36 mg · kg−1 · min−1 preglucagon) was significantly decreased by glucagon replacement (3.83 ± 0.31 mg · kg−1 · min−1 P < 0.02). Mean glucose clearance was also diminished with glucagon (4.49 ± 0.32 versus 5.73 ± 0.45 ml · kg−1 · min−1 preglucagon, P < 0.02). After glucagon administration, no significant change in the percent specific binding of insulin to monocytes could be demonstrated. These data support a role of physiologic concentrations of glucagon in the modulation of peripheral tissue glucose utilization.
To evaluate the pharmacokinetic characteristics of the 2-mg and 4-mg nicotine polacrilex lozenges, the following four separate studies were conducted in healthy adult smokers: (a) A single-dose, four-way crossover (replicate design) study to compare the 4-mg lozenge and the 4-mg nicotine polacrilex gum, (b) a single-dose, two-way crossover study to compare the 2-mg lozenge and the 2-mg gum, (c) a multiple-dose, four-way crossover study to compare the lozenges administered every 90 min and the gums administered every 60 min at 2- and 4-mg dose levels, and (d) a single-dose, three-way crossover study to compare the pharmacokinetic profiles of the 4-mg lozenge when administered in three different ways: (i) Used as directed, (ii) chewed and immediately swallowed, and (iii) chewed, retained in the mouth for 5 min, and then swallowed. The single-dose studies consistently demonstrated 8%–10% higher maximal plasma concentrations and 25%–27% higher AUC values (area under the concentration–time curve) from the lozenges compared with the gums at the 2- and 4-mg dose levels, probably owing to the residual nicotine retained in the gum. The multiple-dose study applying different dosing intervals (i.e., every 90 min for the lozenges and every 60 min for the gums) resulted in approximately 30% lower AUC0–t values for the lozenges compared with those for the gums. Administration of the lozenge contrary to the label-specified instructions for use did not lead to a faster or higher absorption of nicotine. These pharmacokinetic characteristics should allow the lozenge to become an effective and safe therapeutic alternative for smoking cessation.
There is strong evidence that cigarette smoking causes adverse outcomes in people with cancer. However, more research is needed regarding those effects and the effects of alternative tobacco products and of secondhand smoke, the effects of cessation (before diagnosis, during treatment, or during survivorship), the biologic mechanisms, and optimal strategies for tobacco dependence treatment in oncology. Fundamentally, tobacco is an important source of variation in clinical treatment trials. Nevertheless, tobacco use assessment has not been uniform in clinical trials. Progress has been impeded by a lack of consensus regarding tobacco use assessment suitable for cancer patients. The NCI-AACR Cancer Patient Tobacco Use Assessment Task Force identified priority research areas and developed recommendations for assessment items and timing of assessment in cancer research. A cognitive interview study was conducted with 30 cancer patients at the NIH Clinical Center to evaluate and improve the measurement items. The resulting Cancer Patient Tobacco Use Questionnaire (C-TUQ) includes "Core" items for minimal assessment of tobacco use at initial and follow-up time points, and an "Extension" set. Domains include the following: cigarette and other tobacco use status, intensity, and past use; use relative to cancer diagnosis and treatment; cessation approaches and history; and secondhand smoke exposure. The Task Force recommends that assessment occur at study entry and, at a minimum, at the end of protocol therapy in clinical trials. Broad adoption of the recommended measures and timing protocol, and pursuit of the recommended research priorities, will help us to achieve a clearer understanding of the significance of tobacco use and cessation for cancer patients.
The evidence base for the benefit of quitting smoking as regards morbidity and mortality outcomes in patients with moderate-to-severe chronic obstructive pulmonary disease (COPD) is limited. The present article is a review of the existing literature. A systematic literature search in medical databases was performed until March 2006, and subsequently until September 1, 2007. The outcomes examined were COPD-related morbidity and mortality (including all-cause mortality) in COPD patients in connection with smoking cessation. A total of 21 and 27 published articles on morbidity and mortality, respectively, were identified and reviewed. For both outcomes, only a few of the studies included patients with severe COPD. Most of the studies reported a beneficial effect of smoking cessation compared with continued smoking, whereas a few found no improvement. Methodological problems, including small study sizes, poor data quality, possibility of reverse causality and incomplete ascertainment of cause of death, limit interpretation of some of the studies. The evidence as a whole supports the conclusion that, even in severe chronic obstructive pulmonary disease, smoking cessation slows the accelerated rate of lung function decline and improves survival compared with continued smoking.
