1962 The accurate measurement of urinary biomarkers of exposure such as cotinine often requires correcting for urinary dilution using creatinine concentrations. Creatinine reflects renal function in a steady state and is the most commonly used measure of urinary dilution in spot samples. However, differences in creatinine clearance or muscle mass can result in substantial interindividual variation in urinary creatinine levels. This could confound comparisons of creatinine-corrected urinary biomarker values between dissimilar groups. For example, a urinary biomarker comparison between men and women would be affected by differences in muscle mass and creatinine clearance. The present goal was to assess the use of total urine solids as measured by refractive index (RI) as a more appropriate means of accounting for urinary dilution since levels are less dependent on creatinine output. Two hundred and ten healthy adult smokers with similar proportions of men and women, and blacks and whites were recruited from Westchester County, NY. Subjects were non-obese individuals with an average age of about 33 years in each race-sex group. Urine and serum creatinine was measured on a Vitros 500 clinical chemistry analyzer. Urine cotinine was measured by an enzyme immunoassay, and total solids was assessed by refractometry using the following equation: TS=RI20 X 6774-9030. Creatinine clearance was calculated from serum creatinine values using the method of Cockroft and Gault. All analyses were conducted on morning void specimens. There was a high correlation between cotinine/creatinine and cotinine/total solids (r=0.73). The Pearson correlation coefficient ranged from 0.59 in white men to 0.88 in black men. In men, both cotinine measures were about 20% higher in blacks than in whites. There were little differences in creatinine clearance between black and white men. In women, the cotinine/creatinine was higher by 10% in blacks (P=N.S.) and the cotinine/total solids was higher by 35% (P

Cancer of the pancreas is the fourth leading cause of cancer mortality in the USA with an estimated 28 900 deaths in 2001. Several factors have been implicated in the etiology of this disease. However, at present, only cigarette smoking has been positively associated with pancreatic cancer. It is our working hypothesis that tobacco-derived compounds can be delivered to the pancreas where, upon metabolic activation, they can initiate carcinogenesis. Our current investigation was conducted to determine whether cotinine and tobacco-specific nitrosamines (TSNA) are present in human pancreatic juice. Smoking status was assessed by the determination of levels of urinary cotinine and was further supported by quantifying nicotine in hair. The TSNA were extracted from the pancreatic juice of 18 smokers and 9 nonsmokers by supercritical carbon dioxide that contained 10% methanol. The extracts were analyzed for TSNA, namely, 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) and N'-nitrosonornicotine (NNN), by gas chromatography with mass spectrometric detection using a selected ion monitoring technique (GC-SIM-MS). Twenty-three extracts of human pancreatic juice were also analyzed for the presence of the NNK metabolite 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL) by GC-SIM-MS and by gas chromatography interfaced wit a thermal energy analyzer (GC-TEA; TEA, a nitrosamine-specific detector). Cotinine was detected in all analyzed samples of pancreatic juice from smokers (129 +/- 150 ng/mL juice; mean +/- standard deviation) and was present in only two of the nine samples of pancreatic juice from nonsmokers. Its levels in these two samples were 7 and 9 ng/mL juice. NNK was detected in 15 of 18 samples (83%) from smokers at levels from 1.37 to 604 ng/mL pancreatic juice. In nine samples of pancreatic juice from nonsmokers, NNK ranged from not detected (in three samples) to 96.8 ng/mL juice. In pancreatic juice from smokers the mean level of NNK (88.7 +/- 161 ng/mL juice) was significantly higher (p < 0.04) than in that from nonsmokers (12.4 +/- 31.7 ng/mL juice). In addition to NNK, NNN was found in two samples of pancreatic juice of smokers at levels of 68.1 and 242 ng/mL juice; NNN was not detected in any other sample. NNAL was present in 8 of 14 pancreatic juice samples (57%) from smokers and in three of nine samples (33%) from nonsmokers. This research presents preliminary data that supports the hypothesis that pancreatic tissue is exposed to TSNA and that they may be important contributors to pancreatic carcinogenesis in humans.