Sex-based and hormonal contraception effects on the metabolism of nicotine among adolescent tobacco-dependent smokers.

Variations in nicotine metabolism influence smoking patterns. Differences between sexes or related to sex hormones may affect nicotine metabolism. Because smoking initiation starts during adolescence, observations gathered from adolescent smokers might broaden our understanding of such sex-based differences. We tested the hypothesis that nicotine metabolism--as indexed primarily by the ratio of trans-3'-hydroxycotinine (3HC) to cotinine--is more rapid among adolescent girl smokers compared with boys and that regular use of hormonal contraceptives influences nicotine and cotinine metabolism. We also hypothesized that more rapid nicotine metabolism is associated with higher nicotine dependence as indexed by smoking frequency and morning urgency. Plasma samples of nicotine, cotinine, and 3HC concentrations were obtained from 120 adolescents (36 boys). Plasma nicotine and cotinine concentrations were similar in boys and girls. Median plasma 3HC concentrations were 44.45 ng/ml for girls versus 35.74 ng/ml for boys (p = .025), and median plasma 3HC-cotinine ratios were significantly higher in girls than in boys (0.317 vs. 0.253, p = .025). After stratifying girls into two groups based on use versus nonuse of hormonal contraception, plasma 3HC-cotinine ratios in girls using hormonal contraception (0.47) were substantially higher (p<.0001) than in boys (0.25) and were significantly higher than in girls not using hormonal contraception (0.28). Controlling for cigarettes smoked per day, ethnicity, and age did not modify these results. Although plasma nicotine, cotinine, or 3HC concentrations were significantly lower in less dependent adolescent smokers, nicotine and cotinine metabolite ratios were similar. This study showed that hormonal contraception in adolescent girls may accelerate cotinine metabolism, an effect likely related to induction of cytochrome P450 2A6 and independent of ethnicity and cigarette consumption. Prospective controlled studies are needed to further evaluate the role of hormonal contraception in patterns of adolescent smoking and nicotine metabolism.     

An efficient method for enhancing convective heat transfer

A new efficient method for enhancing convective heat transfer in tubular heat exchangers is developed, which can be called the deep profiling method. The potential of the method is illustrated experimentally on a laboratory tube-in-tube heat exchanger.Translated from Teoreticheskie Osnovy Khimicheskoi Tekhnologii, Vol. 38, No. 6, 2004, pp. 634–649.Original Russian Text Copyright © 2004 by Konoplev, Aleksanyan, Rytov, Berlin.     

The association between maternal cocaine use and placenta previa

We compared various diagnostic tests for their abilities to detect Mycobacterium ulcerans infection in specimens from patients with clinically active disease. Specimens from 10 patients from the area of Zangnanado (Department of Zou, Benin) with advanced, ulcerated active M. ulcerans infections were studied by direct smear, histopathology, culture, PCR, and oligonucleotide-specific capture plate hybridization (OSCPH). A total of 27 specimens, including 12 swabs of exudate collected before debridement and 15 fragments of tissue obtained during debridement, were submitted to bacteriologic and histopathologic analysis. The histopathologic evaluation of tissues from all six patients so tested revealed changes typical of those caused by M. ulcerans infection. Five specimens were contaminated, and M. ulcerans was cultivated on L?wenstein-Jensen medium from 12 of the remaining 22 (54.5%) specimens. Detection of mycobacteria was performed by PCR, and M. ulcerans was detected by OSCPH with a new probe (5'-CACGGGATTCATGTCCTGT-3') reacting with M. ulcerans and Mycobacterium marinum. In 10 of 22 (45.5%) specimens, M. ulcerans was identified by PCR-OSCPH. There was no statistically significant difference between the detection of M. ulcerans by culture and by PCR-OSCPH (P > 0.05). This is the first demonstration of an amplification system (PCR-OSCPH) with a sensitivity similar to that of culture for the direct and rapid recognition of M. ulcerans in clinical specimens. This system is capable of identifying M. ulcerans, even in paucibacillary lesions. Our findings suggest that PCR-OSCPH should be used in the quest for the elusive environmental reservoir(s) of M. ulcerans.     

Radiography of the surgical breast biopsy specimen

Seasonal clustering of sarcoidosis presenting with erythema nodosum (EN) has previously been reported only in the northern hemisphere. Of 59 patients presenting to a single centre in New Zealand with a new diagnosis of sarcoidosis, 21 had EN and three more had acute arthralgia without EN. These patients were compared with the rest of the cohort. The patients with EN or arthralgia alone presented exclusively between April and December, with peak clustering in the spring months of August, September and October (p<0.001, Fisher's exact test). This cohort was more likely to have a stage I chest radiograph and to be female (p<0.05), but there were no other differences between the groups. This is the first report of seasonal clustering in the southern hemisphere suggesting a common environmental trigger in the aetiology of sarcoidosis.     

Possible fault detection in cottonball basin,California: an application of radar remote sensing

An analysis of a 3-cm wavelength radar image of Cottonball Basin in Death Valley National Monument has revealed the existence of two suspect fault traces in evaporite deposits that are less than 2000-yr old. The traces are well defined on the image because the radar system was able to differentiate surface roughness variations at the centimeter scale. The features are not recognizable on data sets recorded in the visible and near-infrared spectral bands. Results indicate the potential of radar images as a tool to help locate recent breaks along a fault when the disturbed zone is represented by a somewhat rougher surface than is found in immediately adjacent areas.     

The efficacy and safety of miglitol therapy compared with glibenclamide in patients with NIDDM inadequately controlled by diet alone

OBJECTIVE: To compare the therapeutic effects of the alpha-glucosidase inhibitor miglitol (BAY m 1099), the sulfonylurea glibenclamide, and placebo on parameters of metabolic control and safety in patients with NIDDM that is inadequately controlled by diet alone. RESEARCH DESIGN AND METHODS: After a 4-week placebo run-in period, 201 patients in 18 centers in 4 countries were randomized in a double-blind manner to miglitol (50 mg t.i.d., followed by 100 mg t.i.d.), glibenclamide (3.5 mg q.d/b.i.d.), or placebo for 24 weeks. Efficacy criteria were changes from baseline of HbA1c, fasting and postprandial blood glucose and insulin levels, body weight, and serum triglycerides. RESULTS: Efficacy was assessed in 119 patients who completed the full protocol, and the results were similar to those obtained in 186 patients who fulfilled the validity criteria for analysis. Compared with placebo, mean baseline-adjusted HbA1c decreased by 0.75% (P = 0.0021) and 1.01% (P = 0.0001) in the miglitol and glibenclamide treatment groups, respectively. Blood glucose decreased slightly in the fasting state and considerably in the postprandial state in both treatment groups but not in the placebo group. Fasting insulin levels increased slightly (NS) in all treatment groups; however, postprandial insulin levels decreased with miglitol, while increasing markedly with glibenclamide (P = 0.0001 between all treatment groups). Gastrointestinal side effects (flatulence and diarrhea) occurred mostly in the miglitol-treated patients, while some glibenclamide-treated patients had symptoms suggestive of hypoglycemia. CONCLUSIONS: Miglitol monotherapy is effective and safe in NIDDM patients. Compared with glibenclamide, it reduced HbA1c less effectively and caused more gastrointestinal side effects. On the other hand, glibenclamide, unlike miglitol, tended to cause hypoglycemia, hyperinsulinemia, and weight gain, which are not desirable in patients with NIDDM.