Differentiating between micronucleus dose-responses induced by whole cigarette smoke solutions with Benchmark Dose potency ranking.

Dose-response modeling of in vitro micronucleus test (IVMNT) data was evaluated to determine if the approach has value in discriminating among different tobacco products. Micronucleus responses were generated in L5178Y/Tk+/- mouse lymphoma cells and TK6 human lymphoblastoid cells from a series of whole smoke solutions (WSSs) expected to have different levels of genotoxicity based on differences in their machine-generated smoke constituents. Eight WSSs were prepared by machine smoking different numbers (20 or 60) of two commercial cigarettes (Marlboro Silver or Red) under International Standardization Organization (ISO) or Health Canada Intense (HCI) smoking machine regimens and tested in the two cell lines with and without rat liver S9 activation. The S9-mediated IVMNT dose-response data from the WSSs were evaluated with PROAST software and Benchmark Doses (BMDs) and their upper and lower confidence intervals (CIs) were generated. IVMNT data differed based on the number and type of cigarettes smoked and smoking machine regimen. The IVMNT responses produced in mouse lymphoma cells generally were greater than in TK6 cells, but the ability of the two cell types to differentiate between WSSs was similar. The results indicate that BMD potency ranking was useful for differentiating between IVMNT responses.

Racial and ethnic differences in serum cotinine levels of cigarette smokers: Third National Health and Nutrition Examination Survey, 1988-1991.

CONTEXT: Cotinine, a metabolite of nicotine, is a marker of exposure to tobacco smoke. Previous studies suggest that non-Hispanic blacks have higher levels of serum cotinine than non-Hispanic whites who report similar levels of cigarette smoking. OBJECTIVE: To investigate differences in levels of serum cotinine in black, white, and Mexican American cigarette smokers in the US adult population. DESIGN: Third National Health and Nutrition Examination Survey, 1988-1991. PARTICIPANTS: A nationally representative sample of persons aged 17 years or older who participated in the survey. OUTCOME MEASURES: Serum cotinine levels by reported number of cigarettes smoked per day and by race and ethnicity. RESULTS: A total of 7182 subjects were involved in the study; 2136 subjects reported smoking at least 1 cigarette in the last 5 days. Black smokers had cotinine concentrations substantially higher at all levels of cigarette smoking than did white or Mexican American smokers (P<.001). Serum cotinine levels for blacks were 125 nmol/L (22 ng/mL) (95% confidence interval [CI], 79-176 nmol/L [14-31 ng/mL]) to 539 nmol/L (95 ng/mL) (95% CI, 289-630 nmol/L [51-111 ng/mL]) higher than for whites and 136 nmol/L (24 ng/mL) (95% CI, 85-182 nmol/L [15-32 ng/mL]) to 641 nmol/L (113 ng/mL) (95% CI, 386-897 nmol/L [68-158 ng/mL]) higher than for Mexican Americans. These differences do not appear to be attributable to differences in environmental tobacco smoke exposure or in number of cigarettes smoked. CONCLUSIONS: To our knowledge, this study provides the first evidence from a national study that serum cotinine levels are higher among black smokers than among white or Mexican American smokers. If higher cotinine levels among blacks indicate higher nicotine intake or differential pharmacokinetics and possibly serve as a marker of higher exposure to cigarette carcinogenic components, they may help explain why blacks find it harder to quit and are more likely to experience higher rates of lung cancer than white smokers.

The potentiation of narcotic analgesics with phenothiazines.

Potentiation of narcotic analgesics with phenothiazines have been used for preoperative and postoperative analgesia for a number of years by the podiatric community. The agents most frequently cited in studies are the combination of meperidine with either the phenothiazines chlorpromazine, trimeprazine, or promethazine. Due to the fact that the double-blind clinical studies of pain are mainly subjective, and difficult to quantify, the usefulness of phenothiazines for the sole purpose of potentiation of analgesia is questionable, especially in view of the many side effects of this group of drugs.

Stingray injuries of the foot. Two case reports.

Stingrays, found predominantly in warm coastal waters, are responsible for at least 1,500 human injuries in this country each year. These occur most often in the lower extremity. The authors discuss the symptoms and treatment of stingray injuries and present two case reports.