A comparison of nicotine dose estimates in smokers between filter analysis, salivary cotinine, and urinary excretion of nicotine metabolites

RATIONALE

Nicotine uptake during smoking was estimated by either analyzing the metabolites of nicotine in various body fluids or by analyzing filters from smoked cigarettes. However, no comparison of the filter analysis method with body fluid analysis methods has been published.

OBJECTIVES

Correlate nicotine uptake estimates between filter analysis, salivary cotinine, and urinary excretion of selected nicotine metabolites to determine the suitability of these methods in estimating nicotine absorption in smokers of filtered cigarettes.

MATERIALS AND METHODS

A 5-day clinical study was conducted with 74 smokers who smoked 1-19 mg Federal Trade Commission tar cigarettes, using their own brands ad libitum. Filters were analyzed to estimate the daily mouth exposure of nicotine. Twenty-four-hour urine samples were collected and analyzed for nicotine, cotinine, and 3'-hydroxycotinine plus their glucuronide conjugates. Saliva samples were collected daily for cotinine analysis.

RESULTS

Each method correlated significantly (p < 0.01) with the other two. The best correlation was between the mouth exposure of nicotine, as estimated by filter analysis, and urinary nicotine plus metabolites. Multiple regression analysis implies that saliva cotinine and urinary output are dependent on nicotine mouth exposure for multiple days. Creatinine normalization of the urinary metabolites degrades the correlation with mouth exposure.

CONCLUSIONS

The filter analysis method was shown to correlate with more traditional methods of estimating nicotine uptake. However, because filter analysis is less complicated and intrusive, subjects can collect samples easily and unsupervised. This should enable improvements in study compliance and future study designs.

Effects of subcutaneous methadone, morphine, buprenorphine or saline on thermal and pressure thresholds in cats

This study compared pressure and thermal thresholds after administration of three opioids in eight cats. Pressure stimulation was performed via a bracelet taped around the forearm. Three ball-bearings were advanced against the forearm by inflation of a modified blood pressure bladder. Pressure in the cuff was recorded at the end point (leg shake and head turn). Thermal threshold was tested as previously reported using a heated probe held against the thorax [Dixon et al. (2002) Research in Veterinary Science, 72, 205]. After baseline recordings, each cat received subcutaneous methadone 0.2 mg/kg, morphine 0.2 mg/kg, buprenorphine 0.02 mg/kg or saline 0.3 mL in a four period cross-over study. Measurements were made at 15, 30, 45 min and 1, 2, 3, 4, 8, 12 and 24 h after the injection. Data were analysed by anova (P<0.05). There were no significant changes in thresholds after saline. Thermal threshold increased at 45 min after buprenorphine (maximum 2.8+/-3 degrees C), 1-3 h after methadone (maximum 3.4+/-1.9 degrees C) and 45 min to 1 h (maximum 3.4+/-2 degrees C) after morphine. Pressure threshold increased 30-45 min (maximum 238+/-206 mmHg) after buprenorphine, 45-60 min after methadone (maximum 255+/-232 mmHg) and 45-60 min and 3-6 h (maximum 255+/-232 mmHg) after morphine. Morphine provided the best analgesia, and methadone appears a promising alternative. Buprenorphines limited effect was probably related to the subcutaneous route of administration. Previously, buprenorphine has produced much greater effects when given by other routes.

Cost-effectiveness of screening with contrast enhanced magnetic resonance imaging vs X-ray mammography of women at a high familial risk of breast cancer

Contrast enhanced magnetic resonance imaging (CE MRI) is the most sensitive tool for screening women who are at high familial risk of breast cancer. Our aim in this study was to assess the cost-effectiveness of X-ray mammography (XRM), CE MRI or both strategies combined. In total, 649 women were enrolled in the MARIBS study and screened with both CE MRI and mammography resulting in 1881 screens and 1–7 individual annual screening events. Women aged 35–49 years at high risk of breast cancer, either because they have a strong family history of breast cancer or are tested carriers of a BRCA1, BRCA2 or TP53 mutation or are at a 50% risk of having inherited such a mutation, were recruited from 22 centres and offered annual MRI and XRM for between 2 and 7 years. Information on the number and type of further investigations was collected and specifically calculated unit costs were used to calculate the incremental cost per cancer detected. The numbers of cancer detected was 13 for mammography, 27 for CE MRI and 33 for mammography and CE MRI combined. In the subgroup of BRCA1 (BRCA2) mutation carriers or of women having a first degree relative with a mutation in BRCA1 (BRCA2) corresponding numbers were 3 (6), 12 (7) and 12 (11), respectively. For all women, the incremental cost per cancer detected with CE MRI and mammography combined was £28 284 compared to mammography. When only BRCA1 or the BRCA2 groups were considered, this cost would be reduced to £11 731 (CE MRI vs mammography) and £15 302 (CE MRI and mammography vs mammography). Results were most sensitive to the unit cost estimate for a CE MRI screening test. Contrast-enhanced MRI might be a cost-effective screening modality for women at high risk, particularly for the BRCA1 and BRCA2 subgroups. Further work is needed to assess the impact of screening on mortality and health-related quality of life.

Why does Japan have a high incidence of gastric cancer? Comparison of gastritis between UK and Japanese patients

BACKGROUND AND AIMS

The incidence of gastric cancer in Japan is four times higher than in the UK. It usually arises in a stomach with corpus predominant or pangastritis that has undergone extensive atrophy and intestinal metaplasia. We hypothesised that a Japanese population would have a more severe gastritis with a corpus predominant or pangastritis pattern and a greater degree of atrophy and intestinal metaplasia than that found in the UK. To test this we designed a comparative trial.

METHODS

A total of 252 age matched consecutive patients were recruited from the endoscopy services in Leeds and Tokyo. In each centre, 21 patients were prospectively selected from each decennial, between the ages of 20-80 years. All had epigastric discomfort as their predominant symptom. Patients with peptic ulcer, cancer, and oesophagitis were excluded. Five gastric biopsies were examined by two histopathologists using the updated Sydney system. Helicobacter pylori infection was assessed by histology and culture of biopsies and enzyme linked immunosorbent assay and immunoblot of plasma.

RESULTS

Gastritis was found by both pathologists in 59 (47%) UK and 76 (60%) Japanese patients (chi(2) test, p = 0.04). In those patients with gastritis, corpus predominant or pangastritis was commoner in the Japanese (63% Japan v 36% in the UK (chi(2) test, p = 0.003) Atrophy and intestinal metaplasia were more extensive and severe (Mann-Whitney U test, p<0.001) and chronic inflammation and polymorph activity were also greater, especially in the corpus (Mann-Whitney U test, p<0.001). Fifty three of 59 UK gastritis patients (90%) and 67/76 (88%) (chi(2) test, p = 1) Japanese gastritis patients were positive for H pylori. Using a previously described "gastric cancer risk index" among H pylori positive patients, there were significantly more Japanese than UK subjects with a "high risk" score.

CONCLUSION

In Japanese as opposed to English patients, gastritis is more prevalent and severe with more corpus predominant atrophy and intestinal metaplasia. These differences may partially explain the higher incidence of gastric cancer in Japan.