Assessment of nicotine uptake from cigarette smoke: comparison of a colorimetric test strip (NicCheck I™) and gas chromatography/mass selective detector.

Colorimetric test strip assays are a convenient and inexpensive means for the determination of cotinine in human urine because they can be performed in a nonlaboratory environment using a trained technician. Four hundred human urine samples were separated into four categories: (1) heavy smokers (>20 cigarettes smoked per day), (2) light smokers (<20 cigarettes smoked per day), (3) non-smokers, and (4) vegetarian non-smokers. Samples were evaluated by a gas chromatography/mass selective detector (GC/MSD) method as a reference and using NicCheck I™ (DynaGen, Inc.). Colour intensity can range from 0 (no colour) to 14 (deep pink). Qualitative values were assigned as negative (0), low (1-6) and high (7-14). Comparison of the test strip and GC/MSD results showed: (1) 43 (10.75%) false negatives using the criterion of a GC/MSD cotinine level above 200 ng ml(-1) and test strip reading of 0, (2) 31 (7.75%) false positives using the criterion of a GC/MSD cotinine level below 1 ng ml(-1) and a test strip reading of 1 or greater, and (3) no correlation between the test strip and GC/MSD results (r = 0.597, p < 0.05). The fact that the colorimetric reaction is sensitive to many nicotine metabolites and/or heterocyclic amine structures whereas the GC/MSD method measures nicotine and cotinine selectively might explain the false positive results. False negative results were likely to be due to a lack of sensitivity of the test strip.

Hydroxyurea and trimidox enhance the radiation effect in human pancreatic adenocarcinoma cells.

BACKGROUND: Pancreatic cancer remains the most lethal of all common human malignancies with a 5-year survival rate of lower than 5%. Adjuvant and neoadjuvant preoperative and postoperative chemo-radiotherapy using 5-fluorouracil, have reduced local relapse rate and slightly increased the median survival. Testing new and more potent radiation-sensitising drugs in human pancreatic cancer cells can provide the basis for a more effective chemo-radiation regimen and may consequently improve treatment outcome. MATERIALS & METHODS: The present study was performed to evaluate the efficacy of two potent ribonucleotide reductase (RR) inhibitors: hydroxyurea and trimidox in radio-sensitising Panc-1 human pancreatic cancer cells in an attempt to identify a more effective chemo-radiotherapy regimen with minimal side effects. RESULTS: Treatment of Panc-1 cells with hydroxyurea or trimidox alone for 2 hours was associated with a dose-dependent decrease in their cloning efficacy to similar extent. The IC50 of trimidox, hydroxyurea or radiation alone were 2.5 + 0.3 microM, 39.0 + 0.4 microM and 3.2 + 0.2 Gy, respectively. Treatment with 39.0 microM non-cytotoxic IC50 dose of hydroxyurea for two hours before or immediately after radiation reduced the IC50 of radiation to only 1.1 + 0.14 or 1.0 + 0.1 Gy, respectively. Treatment with 2.5 microM non-cytotoxic IC50 dose of trimidox for two hours before or immediately after radiation reduced the IC50 of radiation to only 1.2 + 0.16 or 1.4 + 0.12 Gy, respectively. The mean radiation enhancement ratios were 2.9 and 3.2 for hydroxyurea before and immediately after radiation. The greater radio-sensitising effect of hydroxyurea compared to trimidox or gemcitabine could be due to its unique double action by synchronising the cancer cells into the radiosensitive G1/S border and inhibiting DNA damage repair. CONCLUSIONS: The present study demonstrates the superiority of hydroxyurea at non-cytotoxic doses compared to the other two recent RR inhibitors: gemcitabine and trimidox in radio-sensitising human pancreatic cancer cells. Hydroxyurea combined with radiation has significantly improved progression-free survival of advanced cervical cancer and glioblastoma patients and showed clinical benefit in combination with other chemotherapy drugs in advanced pancreatic cancer. The present results suggest the clinical use of hydroxyurea as a radiosensitiser in both pre- and post-operative chemo-radiotherapy in pancreatic cancer patients. Given the demonstrated potent radio-sensitising effect of hydroxyurea at non-cytotoxic doses when administered before or immediately after radiation and its low clinical toxicity, it should be feasible to administer hydroxyurea both before and after radiation in pancreatic cancer patients.

Teaching behavioral medicine using individual coronary heart disease risk factors.

Two hundred twenty-one first-year medical students participated in a voluntary coronary heart disease risk factor self-change project designed to teach the principles of behavioral change. Blood pressure, serum lipids, percentage body fat, cardiovascular fitness, and smoking status were measured prior to the project. Students designed their own programs of behavior modification and, after 8 weeks, repeat measurements were obtained in students whose projects related to coronary heart disease risk (56% of entire group). Despite generally low initial coronary heart disease risk factors, most risk factor groups successfully altered the targeted risk factors. The subgroup attempting to lower serum cholesterol (n = 49) reduced total cholesterol 15 +/- 24 mg/dl (mean +/- SD) and low-density lipoprotein cholesterol 11 +/- 20 mg/dl (P less than 0.001 for both). The blood pressure group (n = 9) decreased systolic blood pressure 8 +/- 10 mm Hg (P less than 0.05), and the weight-loss group (n = 33) lost 3.0 +/- 2.9 kg (P less than 0.001), reducing estimated percentage body fat 1.7 +/- 1.8 (P less than 0.001). The self-change project was well received by the students and appears to be a useful technique for introducing the principles of behavioral medicine to first-year medical students.

Measuring patient attitudes in a comprehensive health care setting.

Systematic patient feedback is important for assessing the impact of existing hospital policy on patients and for providing a base for continuing inservice training of personnel. Health professionals need to have knowledge of patient attitudes about quality of care, interpersonal relations, treatment methods, health status and rights, and the health facility process. A unique combination of the Rosenberg-Fishbein, AID, and psychographic models has considerable promise for objective measurement of patient attitudes over a wide range of health care activities. The model is discussed in terms of a recent patient attitude survey conducted at a major consolidated health care agency in an SMSA of the southeast which provides common management policy and consolidated financial services for two separate hospital facilities.

Selenosis, hepatic selenium accumulation, and plasma glutathione peroxidase activity in chicks as affected by a factor in linseed meal.

Linseed meal has previously been reported to contain an organic factor that reduces toxicity of selenium in animals. The purpose of the studies reported here was to obtain information on the mechanism of action of the linseed meal factor in counteracting selenosis in chicks. Feeding a diet containing 20% linseed meal to chicks partially counteracted the growth depression caused by including high levels of selenium (10-40 ppm) in the diet. In contrast to the rat, chicks fed diets containing selenium did not accumulate significantly more of the element per unit of liver dry matter when the diet contained linseed meal, and at two selenium levels accumulated significantly less. Linseed meal did not interfere with the absorption of an oral dose of 75Se as measured by tissue retention 24 hours later. A methanol extract of linseed meal did not interfere with the normal increase in plasma glutathione peroxidase activity in chicks fed diets supplemented with low levels of selenium even though the extract counteracted the growth depression obtained by adding 20 ppm selenium. Linseed meal contains a factor that interacts with selenium in the tissues in some unknown way to reduce the toxic effects of the element, but does not prevent normal synthesis of glutathione peroxidase.