Do Public Smoking Bans have an Impact on Active Smoking? Evidence from the UK

The literature on the effects of public smoking bans on smoking behaviour presents conflicting results and there is limited evidence on their impact on active smoking. This paper evaluates the impact of smoking bans on active smoking using data from the British Household Panel Survey and exploiting the policy experiment provided by the differential timing of the introduction of the bans in Scotland and England. We assess the short‐term impact of the smoking bans by employing a series of flexible difference‐in‐differences fixed effects panel data models. We find that the introduction of the public smoking bans in England and Scotland had limited short‐run effects on both smoking prevalence and the total level of smoking. Although we identify significant differences in trends in smoking consumption across the survey period by population sub‐groups, we find insufficient evidence to conclude that these were affected by the introduction of the smoking bans. These results challenge those found in the public health literature but are in line with the most recent strand of economic literature indicating that there is no firm evidence on the effects of smoking bans on smoking. Copyright © 2013 John Wiley & Sons, Ltd.     

Increased cerebrospinal fluid corticotropin-releasing factor concentrations during tryptophan depletion in healthy adults.

BACKGROUND: Brain serotonin neurotransmission and hypothalamic-pituitary-adrenal axis function are implicated in the pathophysiology of depression, and these systems interact in a reciprocal modulatory fashion. This study examined the effect of tryptophan depletion, which acutely reduces brain serotonin concentrations, on serial cerebrospinal fluid concentrations of corticotropin-releasing factor in healthy humans. METHODS: Five subjects completed a standard tryptophan depletion protocol, and four subjects participated in a comparison condition. Subjects underwent continuous sampling of cerebrospinal fluid via lumbar peristaltic pump. Concentrations of cerebrospinal fluid corticotropin-releasing factor were measured by radioimmunoassay. RESULTS: No mood changes were observed in either group. Tryptophan-depleted subjects exhibited significantly greater increases in corticotropin-releasing factor concentrations over time than subjects in the comparison condition. CONCLUSIONS: These findings highlight the potential importance of corticotropin-releasing factor and serotonin interactions and suggest that activation of corticotropin-releasing-factor-containing neurons could play a role in the emergence of mood symptoms following tryptophan depletion in vulnerable individuals.     

Gender Effects Following Repeated Administration of Cocaine and Alcohol in Humans

Meta-analysis is applied to aggregate-level studies that model the demand for cigarettes using static, myopic, or rational addiction frameworks in an attempt to synthesize key findings in the literature and to identify determinants of the variation in reported price elasticity estimates across studies. The results suggest that the rational addiction framework produces statistically similar estimates to the static framework but that studies that use the myopic framework tend to report more elastic price effects. Studies that applied panel data techniques or controlled for cross-border smuggling reported more elastic price elasticity estimates, whereas the use of instrumental variable techniques and time trends or time dummy variables produced less elastic estimates. The finding that myopic models produce different estimates than either of the other two model frameworks underscores that careful attention must be given to time series properties of the data.     

The small GTPase ADP-Ribosylation Factor 1 mediates the sensitivity of triple negative breast cancer cells to EGFR tyrosine kinase inhibitors

The clinical use of EGFR-targeted therapy, in triple negative breast cancer patients, has been limited by the development of resistance to these drugs. Although activated signaling molecules contribute to this process, the molecular mechanisms remain relatively unknown. We have previously reported that the small GTPase ADP-Ribosylation Factor 1 (ARF1) is highly expressed in invasive breast cancer cells and acts as a molecular switch to activate EGF-mediated responses. In this study, we aimed at defining whether the high expression of ARF1 limits sensitivity of these tumor cells to EGFR inhibitors, such as gefitinib. Here, we show that the knock down of ARF1 expression or activity decreased the dose and latency time required by tyrosine kinase inhibitors to induce cell death. This may be explained by the observation that the depletion of ARF1 suppressed gefitinib-mediated activation of key mediators of survival such as ERK1/2, AKT and Src, while enhancing cascades leading to apoptosis such as the p38MAPK and JNK pathways, modifying the Bax/Bcl2 ratio and cytochrome c release. In addition, inhibiting ARF1 expression and activation also results in an increase in gefitinib-mediated EGFR internalization and degradation further limiting the ability of this receptor to promote its effects. Interestingly, we observed that gefitinib treatment resulted in the enhanced activation of ARF1 by promoting its recruitment to the receptor AXL, an important mediator of EGFR inhibition suggesting that ARF1 may promote its pro-survival effects by coupling to alternative mitogenic receptors in conditions where the EGFR is inhibited. Together our results uncover a new role for ARF1 in mediating the sensitivity to EGFR inhibition and thus suggest that limiting the activation of this GTPase could improve the therapeutic efficacy of EGFR inhibitors.     

Developmental defects in zebrafish for classification of EGF pathway inhibitors

One of the major challenges when testing drug candidates targeted at a specific pathway in whole animals is the discrimination between specific effects and unwanted, off-target effects. Here we used the zebrafish to define several developmental defects caused by impairment of Egf signaling, a major pathway of interest in tumor biology. We inactivated Egf signaling by genetically blocking Egf expression or using specific inhibitors of the Egf receptor function. We show that the combined occurrence of defects in cartilage formation, disturbance of blood flow in the trunk and a decrease of myelin basic protein expression represent good indicators for impairment of Egf signaling. Finally, we present a classification of known tyrosine kinase inhibitors according to their specificity for the Egf pathway.     

Metabolism of deltamethrin and cis- and trans-permethrin by rat and human liver microsomes,liver cytosol and plasma preparations

1. The metabolism of deltamethrin (DLM), cis-permethrin (CPM) and trans-permethrin (TPM) was studied in liver microsomes, liver cytosol and plasma from male Sprague–Dawley rats aged 15, 21 and 90 days and from adult humans.

2. DLM and CPM were metabolised by rat hepatic microsomal cytochrome P450 (CYP) enzymes and to a lesser extent by microsomal and cytosolic carboxylesterase (CES) enzymes, whereas TPM was metabolised to a greater extent by CES enzymes.

3. In human liver, DLM and TPM were mainly metabolised by CES enzymes, whereas CPM was metabolised by CYP and CES enzymes.

4. The metabolism of pyrethroids by cytosolic CES enzymes contributes to the overall hepatic clearance of these compounds.

5. DLM, CPM and TPM were metabolised by rat, but not human, plasma CES enzymes.

6. This study demonstrates that the ability of male rats to metabolise DLM, CPM and TPM by hepatic CYP and CES enzymes and plasma CES enzymes increases with age. In all instances, apparent intrinsic clearance values were lower in 15 than in 90?day old rats. As pyrethroid-induced neurotoxicity is due to the parent compound, these results suggest that DLM, CPM and TPM may be more neurotoxic to juvenile than to adult rats.

     

HIV Testing of Tuberculosis Patients by Public and Private Providers in New York City

Thirty percent of tuberculosis (TB) patients in New York City in 2007 were not tested for HIV, which may be attributable to differential testing behaviors between private and public TB providers. Adult TB cases in New York City from 2001 to 2007 (n = 5,172) were evaluated for an association between TB provider type (private or public) and HIV testing. Outcomes examined were offers of HIV tests and patient refusal of HIV testing, using multivariate logistic and binomial regression, respectively. HIV test offers were less frequent among patients who visited only private providers than patients who visited only public providers [males: adjusted odds ratio (aOR) 0.33, 95 % confidence interval (CI) 0.15–0.74; females: aOR 0.26, 95 % CI 0.12–0.57]. Changing from private to public providers was associated with an increase in HIV tests offered among male patients (aOR 1.96, 95 % CI 1.04–3.70). Among patients who did not use substances, those who visited only private providers were more likely to refuse HIV testing than those who visited only public providers [males: adjusted prevalence ratio (aPR) 1.26, 95 % CI 0.99–1.60; females: aPR 1.78, 95 % CI 1.43–2.22]. Patients of private providers were less likely to have an HIV test performed during their TB treatment. Education of TB providers should emphasize HIV testing of all TB patients, especially among patients who are traditionally considered low-risk.