Citations

A rapid method for measuring nicotine concentration in serum and urine is described. Deuterated nicotine is used as an internal standard. Nicotine and deuterated nicotine are extracted using a copolymeric-bonded phase silica column. The extract is analysed by gas chromatography coupled with mass spectrometry (GC/MS) operating in selected ion monitoring mode. The method has a lower limit of detection of approximately 2 μg/L and is linear to at least 2000 μg/L. Within-run percentage coefficients of variation (% CV) are < 4 in both assays over a nicotine concentration range of 10–2000 μg/L. Between-run %CV in the serum assay are 5.4, 5.2, 4.8 and 5.9, respectively, at nicotine concentrations of 10, 15, 25, and 50 μg/L. Between-run %CV in the urine assay are 5.9, 4.5, 2.7 and 5.2, respectively, at nicotine concentrations of 100, 250, 500, and 2000 μg/L. The absolute recovery of nicotine is 61±+6% (mean±SD) over the range of 10–250 μg/L. The assay has been used to measure serum nicotine concentrations and 24-h urinary excretion of nicotine to monitor the extent of replacement in subjects receiving transdermal nicotine therapy for smoking cessation.

Abstract Previous research has suggested that nicotine may be therapeutically useful in the treatment of sleep-disordered breathing. The development of transdermal nicotine delivery systems has allowed us to test the overnight effectiveness of nicotine. Twenty nonsmoking subjects (10 men, 10 women) were recruited on the basis of a history of habitual snoring that was confirmed by overnight laboratory monitoring. Subjects were then randomized (double-blind crossover design) to receive either placebo or an active patch that delivers 11 mg of nicotine over a 24-h period. Patches were applied at 6 P.M. and removed at 6 A.M. the following morning, at which time venous blood was obtained for determination of serum nicotine concentrations. Polysomnography was performed using standard techniques to assess sleep architecture and sleep-disordered breathing. Snoring was monitored with a sound-level meter and quantitatively analyzed to determine the snoring index (SI) (number of snores per hour of sleep) and mean and maximum snoring intensities. The age of the subjects was 46.9 +/- 11.4 yr (mean +/- SD) and their mean body mass index (BMI) 33.3 +/- 4.6 kg/m2. A mean nicotine level was nondetectable with placebo and 7.8 +/- 2.3 ng/ml with wearing of an active patch. Nicotine decreased total sleep time (TST) by 33 min (p &lt; or 0.01), sleep efficiency from 89.7 to 83.5% (p &lt; or = 0.01), and percent rapid eye movement (REM) sleep from 18.8 to 15.1% (p &lt; or = 0.01), and prolonged initial sleep latency (ISL) from 6.7 to 18.2 min (p &lt; or = 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

The risk of falling reportedly increases almost 2.5-times in those with lower extremity osteoarthritis (OALE) compared with age-matched controls. However, the mechanisms underlying the increased risk are not clear. The risk factors for falls in people with OALE found in the literature are mostly the same as the risk factors for people without OALE. It is hypothesized that risk factors for falls are exacerbated by OALE, such that these individuals are more likely to become dynamically unstable and, once this has occurred, are less able to perform an appropriate compensatory stepping response compared with people without OALE. To the extent that this is true, task-specific training targeting the compensatory step, which decreases falls in middle-aged and older women, should be effective for people with OALE. The purpose of the present review is to provide the rationale for the above hypothesis. Furthermore, the present authors present evidence that the fall risk of people with OALE could be efficiently and effectively reduced using task-specific training previously shown to reduce falls in middle aged and older women.