Cigarette smoking and cancer risk: modeling total exposure and intensity

A recent analysis showed that the excess odds ratio (EOR) for lung cancer due to smoking can be modeled by a function which is linear in total pack-years and exponential in the logarithm of smoking intensity and its square. Below 15-20 cigarettes per day, the EOR/pack-year increased with intensity (direct exposure rate or enhanced potency effect), suggesting greater risk for a total exposure delivered at higher intensity (for a shorter duration) than for an equivalent exposure delivered at lower intensity. Above 20 cigarettes per day, the EOR/pack-year decreased with increasing intensity (inverse exposure rate or reduced potency effect), suggesting greater risk for a total exposure delivered at lower intensity (for a longer duration) than for an equivalent exposure delivered at higher intensity. The authors applied this model to data from 10 case-control studies of cancer, including cancers of the lung, bladder, oral cavity, pancreas, and esophagus. At lower intensities, there was enhanced potency for several cancer sites, but narrow ranges for pack-years increased uncertainty, precluding definitive conclusions. At higher intensities, there was a consistent reduced potency effect across studies. The intensity effects were statistically homogeneous, indicating that after accounting for risk from total pack-years, intensity patterns were comparable across the diverse cancer sites.     

Biological,Familial, and Peer Influences on Dating in Early Adolescence

The current study examined the joint contributions of pubertal maturation, parental monitoring, involvement in older peer groups, peer dating, and peer delinquency on dating in a sample of early adolescent boys and girls. The sample consisted of 784 adolescents (394 boys, 390 girls) enrolled in grades 5, 6, and 7 who were followed for one year. In addition to measures of pubertal maturation and parental monitoring, adolescents and their peer group members completed indices of dating and delinquency. Average dating and delinquency scores for each participant's peer group network were computed. Results indicated that it was the combination of pubertal maturation, peer delinquency, and peer dating that explained increases in early dating. For boys only, parental monitoring was a significant predictor. The more knowledgeable parents were about their boys' activities, the lower the number of dating activities reported. These results highlight the importance of considering the joint effects of these biological and social predictors in understanding early dating. When rapid changes occur in all three domains, early dating is most likely to ensue. The findings of this study have practical importance. Parents and professionals who work closely with youth should attend to the special vulnerability of early maturing adolescents in the face of peer pressure and to the important role of parental monitoring in regulating dating activities.     

Fourteen-day safety and acceptability study of the universal placebo gel

OBJECTIVE: This study evaluated the effect of the so-called universal placebo compared to the polystyrene sulfonate (PSS) placebo on genital irritation. DESIGN: A single-center, Phase I, randomized, closed-label study was performed to evaluate the genital irritation of microbicide placebo gels. Thirty healthy, sexually abstinent women were randomly assigned to apply 3.5 mL of either the universal placebo or the PSS placebo gel intravaginally twice daily for 14 days. METHODS: Genital irritation was assessed by signs as seen on pelvic examination and colposcopy and reports of symptoms. Vaginal health was assessed by wet mounts, Gram stains for Nugent score and polymorphonuclear leukocytes, and semiquantitative vaginal cultures. Acceptability was assessed as reported on the follow-up questionnaire. RESULTS: The universal placebo was less irritating than the PSS placebo with a lower proportion of women experiencing signs and/or symptoms of genital irritation throughout follow-up (36% compared to 80%, p=.0253). The universal placebo was associated with few and mild genital symptoms, few and minor colposcopic findings and good vaginal health with no clinically significant changes in genital flora. Most participants found the feel of the universal placebo gel neutral or pleasant, and all participants found it odorless. CONCLUSIONS: The universal placebo appeared safe and acceptable when used twice daily for 14 days. The strategy of creating a de novo inert universal placebo is a successful approach. The universal placebo is appropriate for use as a placebo gel in HIV prevention trials with microbicide candidates.     

Drug use and sexual behaviors reported by adults: United States, 1999-2002

This report presents prevalence estimates for self-reported adult drug use and sexual behaviors in the United States. Data are from the National Health and Nutrition Examination Survey (NHANES) collected from 1999 to 2002. NHANES surveys a stratified multistage probability sample of the civilian noninstitutionalized population of the United States. Tables included in this report present estimates for use of cocaine, including crack or freebase, or other street drugs, and sexual behavior by selected sociodemographic characteristics among adults 20-59 years of age.     

The effect of stress on men's food selection

This study investigates the effect of stress on food choice among men. Two groups of men were given either solvable (no-stress) or unsolvable (stress) anagrams to solve. Four bowls of snack foods-two healthy (peanuts and grapes) and two unhealthy (potato chips and M&M chocolate candies)-were available and subjects were invited to snack on them. Men in the no-stress group ate significantly more of the unhealthy foods than did men in the stress group. This finding is quite different from that found with women [Zellner et al. (2006). Food selection changes under stress. Physiology & Behavior, 87, 789-793]. Women tended to eat more grapes when not stressed than when stressed and more M&Ms when stressed than when not stressed. Thus, the effect of stress level on food choice is different for men and women.     

Chemokine and cytokine gene expression profiles in chickens inoculated with Mycoplasma gallisepticum strains Rlow or GT5

Mycoplasma gallisepticum infection in chickens leads to tracheitis, airsacculitis, poor feed conversion and reduced egg production, resulting in considerable economic hardship on the poultry industry. The chemokines and cytokines responsible for recruitment, activation and proliferation of leukocytes in affected tissues have not been described. In the current study, chemokine and cytokine gene expression profiles were investigated in tracheas of chickens inoculated with M. gallisepticum strains R(low) (pathogenic) and GT5 (attenuated) at days 1, 4 and 8 post-inoculation. Expression of lymphotactin mRNA was higher in R(low)-inoculated chickens than GT5- or PBS-inoculated chickens, while CXCL13/BCA1 mRNA expression level was higher in both GT5- or R(low)-inoculated chickens than in PBS-inoculated controls on day 1 post-inoculation. However, both R(low) and GT5 strains induced a down-regulation in mRNA expression of CCL20, IL-1beta, IL-8 and IL-12p40 genes, with CCL20 and IL-12 mRNA levels remaining lower on days 4 and 8 post-inoculation. On day 4, R(low)-inoculated chickens exhibited significantly higher tracheal lesion scores and higher levels of lymphotactin, CXCL13, CXCL14, RANTES, MIP-1beta, IL-1beta and IFN-gamma mRNA compared to PBS-inoculated controls. The mRNA levels of these genes were also higher in R(low)-inoculated chickens that had moderate to severe tracheal lesion scores on day 8 post-inoculation. These results reflect the importance of lymphocyte and monocyte chemotactic factors in the development of tracheal lesions in chickens inoculated with M. gallisepticum strain R(low). Our data also suggest that M. gallisepticum may modulate the host response causing dramatic decreases in CCL20, IL-8 and IL-12 mRNA levels in GT5- or R(low)-inoculated chickens as early as one day post-inoculation.     

Non-toxic Pseudomonas aeruginosa exotoxin A expressing the FMDV VP1 G-H loop for mucosal vaccination of swine against foot and mouth disease virus

Synthetic peptides derived from the G-H loop of the foot and mouth disease virus (FMDV) capsid protein VP1 are relatively poor at recapitulating the native conformation present in the virus, and thus are often poor immunogens. We hypothesized that a candidate mucosal vaccine against FMDV could be developed using the non-toxic Pseudomonas aeruginosa exotoxin A (ntPE) to deliver the G-H loop in its native conformation. An added benefit of this approach is the potential for ntPE to serve as an effective carrier/adjuvant molecule for delivery of the fusion protein across the epithelial barrier by virtue of its capacity to bind to CD91. A chimeric protein (ntPE-GH) was generated by inserting the coding sequence of the G-H loop into an expression plasmid encoding ntPE, in place of the native Ib loop. Recombinant ntPE-GH and wild-type ntPE were each expressed in Escherichia coli, purified over a nickel resin, then administered intranasally to the pigs, with or without the mucosal adjuvant cholera toxin (CT). Both the ntPE and ntPE-GH induced mucosal and systemic immune responses against ntPE; moreover, ntPE-GH administered without CT induced anti-GH loop serum IgG antibodies. In conclusion, these data demonstrate that ntPE can be used as a mucosal carrier/adjuvant to induce an immune response against the VP1 G-H loop of FMDV.