Changes in Cigarettes per Day and Biomarkers of Exposure Among US Adult Smokers in the Population Assessment of Tobacco and Health Study Waves 1 and 2 (2013-2015)

INTRODUCTION

Some studies have found some reduction in tobacco exposure and tobacco-related disease risk with decreased numbers of cigarettes smoked per day (CPD), but biomarker of exposure estimates by change in CPD are generally unavailable for the US population.

METHODS

We analyzed biomarker of exposure data by smoking status from over 1100 adult exclusive daily cigarette smokers in Wave 1 of the Population Assessment of Tobacco and Health (PATH) Study who were either exclusive daily smokers or had quit tobacco use entirely at Wave 2. Wave 1 smoking categories consisted of "very light" (1-4 CPD), "light" (5-9 CPD), "moderate" (10-19 CPD), and "heavy" (20+ CPD), and Wave 2 categories were "quitters" (stopped smoking entirely), exclusive cigarette "reducers" (CPD decreased ≥ 50%), "maintainers" (CPD within 50%-150% of Wave 1 value), and "increasers" (CPD increased ≥ 50%).

RESULTS

Complete quitters had significantly lower levels of TNE-2, NNAL, NNN, 2-Fluorene, HPMA, CYMA, and MHB3 at Wave 2 for all Wave 1 CPD categories, and decreases were often large. Moderate "reducers" had lower levels of NNAL and 1-Hydroxypyrene at Wave 2, and heavy "reducers" had lower levels of NNAL, 2-Fluorene, and MHB3. Light "increasers" had higher levels of TNE-2, NNAL, 2-Fluorene, CYMA, and cadmium at Wave 2, and heavy "increasers" had higher levels of NNAL and HPMA.

CONCLUSIONS

Smoking "reducers" and "increasers" had changes in some biomarker of tobacco exposure levels, but reductions were much greater and more consistent for complete quitters.

IMPLICATIONS

PATH longitudinal cohort study data show that some exclusive daily cigarette smokers increase or decrease CPD over time. These differences may result in moderate changes in the levels of some biomarkers such as NNAL. Even so, however, reductions in biomarker levels are much greater with complete smoking cessation.

Changes in Cigarette Consumption With Reduced Nicotine Content Cigarettes Among Smokers With Psychiatric Conditions or Socioeconomic Disadvantage: 3 Randomized Clinical Trials

IMPORTANCE

This study is part of a programmatic effort evaluating the effects of reducing nicotine content of cigarettes to minimally addictive levels.

OBJECTIVE

To examine whether very low-nicotine-content (VLNC) cigarettes decrease smoking rates and dependence severity among smokers with psychiatric disorders or socioeconomic disadvantage.

DESIGN, SETTING, AND PARTICIPANTS

These 3 randomized clinical trials were performed at the University of Vermont, Brown University, and Johns Hopkins University between October 2016 and September 2019. Participants received 12 weeks of exposure to study cigarettes with nicotine content ranging from levels representative of commercial cigarettes (15.8 mg nicotine/g tobacco) to less than a hypothesized addiction threshold (2.4 mg/g and 0.4 mg/g). Daily smokers from 3 at-risk populations participated: individuals with affective disorders, exemplifying smokers with mental illness; individuals with opioid use disorder, exemplifying smokers with substance use disorders; and women with high school educations or less, exemplifying smokers with socioeconomic disadvantage. Data were analyzed from September 2019 to July 2020.

INTERVENTIONS

Random assignment to 1 of 3 study cigarettes provided weekly at no cost for 12 weeks.

MAIN OUTCOMES AND MEASURES

The primary outcome was between-group differences in mean total cigarettes smoked daily (CPD) during week 12; secondary outcomes included CPD for study and nonstudy cigarettes and dependence severity across weeks analyzed using analysis of covariance, random coefficients growth modeling, or repeated measures analysis of variance.

RESULTS

A total of 775 participants were included (mean [SD] age, 35.59 [11.05] years; 551 [71.10%] women [owing to 1 population being exclusively women]); participants smoked a mean (SD) of 17.79 (9.18) CPD at study intake. A total of 286 participants were randomized to 0.4 mg/g, 235 participants were randomized to 2.4 mg/g, and 254 participants were randomized to 15.8 mg/g. Participants randomized to VLNC cigarettes had decreased mean [SEM] total CPD during week 12 across populations (Cohen d = 0.61; P < .001). At week 12, mean (SEM) CPD decreased to 17.96 (0.98) CPD in the 0.4 mg/g group and to 19.53 (1.07) CPD in the 2.4 mg/g group, both of which were significantly different from the 15.8 mg/g group (25.08 [1.08] CPD at week 12) but not each other (0.4 mg/g adjusted mean difference: -7.54 [95%CI, -9.51 to -5.57]; 2.4 mg/g adjusted mean difference: -5.34 [95% CI, 7.41 to -3.26]). Several secondary outcomes differed across populations randomized to VLNCs, including mean total CPD across weeks, with linear trends lower in participants receiving 0.4 mg/g (-0.28 [95%CI, -0.39 to -0.18]; P < .001) and 2.4 mg/g (-0.13 [95%CI, -0.25 to -0.01]; P < .001) doses compared with those receiving the 15.8 mg/g dose (0.30 [95% CI, 0.19 to 0.41]). Fagerström Test of Nicotine Dependence mean total scores were significantly lower in participants who received VLNCs (Cohen d = 0.12; P < .001), with those who received the 0.4 mg/g dose (mean [SD] score, 3.99 [0.06]; P < .001 vs 15.8 mg/g) or 2.4 mg/g dose (mean [SD] score, 4.07 [0.06]; P = .01 vs 15.8 mg/g) differing from those who received the 15.8 mg/g dose (mean [SD] score, 4.31 [0.06]) but not from each other.

CONCLUSIONS AND RELEVANCE

These findings demonstrate that decreasing the nicotine content of cigarettes to very low levels reduced smoking rate and nicotine-dependence severity in these high-risk populations, effects that may facilitate successful cessation.

TRIAL REGISTRATION

ClinicalTrials.gov Identifiers: NCT02232737, NCT02250664, NCT02250534.

Associations of Cigarettes Smoked Per Day with Biomarkers of Exposure Among U.S. Adult Cigarette Smokers in the Population Assessment of Tobacco and Health (PATH) Study Wave 1 (2013-2014)

BACKGROUND

The dose-response relationships between number of cigarettes smoked per day (CPD) and health outcomes, such as cancer and heart disease, are well established, but much less is known about the relationships between CPD and biomarkers of exposure.

METHODS

We analyzed biomarker data by CPD from more than 2,700 adult daily cigarette smokers in Wave 1 of the Population Assessment of Tobacco and Health Study. Tobacco use categories consisted of exclusive cigarette smokers, dual cigarette and e-cigarette users, and dual cigarette and smokeless tobacco users.

RESULTS

Biomarker concentrations consistently increased with CPD for each tobacco user group, although concentrations tended to level off at high smoking levels, such as those at and above 20 CPD. Dual cigarette and e-cigarette users had higher levels of some biomarkers such as Total Nicotine Equivalents-2 (P = 0.0036) than exclusive cigarette smokers, and dual cigarette and smokeless tobacco users had higher levels of 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (P < 0.0001) and N'-nitrosonornicotine (P = 0.0236) than exclusive cigarette smokers.

CONCLUSIONS

Among daily smokers, exposure to tobacco toxicants and constituents exhibits a dose-response relationship by number of cigarettes smoked, but the relationship is not necessarily linear in form. Dual users of cigarettes with either e-cigarettes or smokeless tobacco are exposed to higher levels of certain toxicants and carcinogens than exclusive cigarette smokers.

IMPACT

Availability of biomarker data by CPD may aid in comparisons between cigarette smoking and use of new and potentially reduced exposure tobacco products, which may result in different levels of constituent and toxicant exposure.

Abstract P5-18-01: Risk of contralateral breast cancer (CBC) in women with ductal carcinoma in situ (DCIS) with and without and synchronous lobular carcinoma in situ (LCIS)

Background: LCIS is considered a risk factor for bilateral breast cancer, but the effect of LCIS diagnosed concurrently with DCIS is not known. We sought to compare CBC and ipsilateral breast tumor recurrence (IBTR) rates in women with DCIS with and without synchronous LCIS treated with breast conserving surgery (BCS).

Methods: A prospectively maintained database of DCIS patients undergoing BCS from 2000-2011 was used to identify women with a contralateral breast at risk. Patients with synchronous ipsilateral LCIS found at core needle biopsy or surgical excision were included in the “DCIS + LCIS” group; those with contralateral or bilateral LCIS were excluded. Associations of patient, tumor, and treatment factors with CBC and IBTR were evaluated using logistic regression.

Results: Of the 1888 patients identified, 1475 (78%) had DCIS only and 413 (22%) had DCIS with synchronous LCIS. Median follow-up was 7.5 years (range 0-17 years). 305 patients had a subsequent breast event; 216 IBTR and 89 CBC.

The 5 and 10-year cumulative incidence of IBTR was similar in both groups: 6.3% and 14.4% for DCIS only, compared with 5.9% and 14.0% for DCIS + LCIS (p = 0.94), respectively. The 5 and 10-year cumulative incidence of CBC was significantly greater in the DCIS + LCIS group: 5.7% and 10.0%, compared with 2.4% and 5.0% for DCIS only (p &lt; 0.001).

Table 1 summarizes uni-and multi-variable analyses of risk factors associated with CBC and IBTR among women with DCIS treated with BCS. After adjustment for other factors, CBC risk was more than 2-fold higher in the DCIS + LCIS group compared with the DCIS only group (HR 2.37, 95% CI 1.54-3.65, p &lt; 0.001). There was no difference in IBTR risk based on presence of synchronous LCIS. Younger age and receipt of endocrine therapy were significantly associated with decreased risk of CBC.

Table 1:Risk factors associated with CBC and IBTR in patients with DCIS treated with BCS  Univariate Analysis Multivariate Analysis  Hazard Ratio (95% CI) Hazard Ratio (95% CI)  CBC IBTR CBC IBTRAge (continuous)1.02 (1.01-1.04) *0.99 (0.98-1.0)1.02 (1.0-1.04) *0.99 (0.97-1.0) *Presentation    Radiologic1111Clinical0.36 (0.11-1.14)1.56 (1.05-2.3) *0.41 (0.13-1.31)1.67 (1.12-2.47) *Family history    Yes1.32 (0.87-2.01)1.0 (0.76-1.32)1.33 (0.87-2.03)1.03 (0.78-1.35)Grade    Low1111Intermediate/high1.83 (1.0-3.37)1.32 (0.93-1.88)1.74 (0.92-3.29)1.62 (1.11-2.35) *Radiation    Yes1.16 (0.75-1.8)0.7 (0.54-0.92) *1.14 (0.71-1.82)0.64 (0.48-0.86) *Endocrine Therapy    Yes0.43 (0.23-0.81) *0.51 (0.35-0.74) *0.42 (0.22-0.8) *0.53 (0.36-0.77) *DCIS group    DCIS only1111DCIS + LCIS2.28 (1.49-3.5) *0.99 (0.71-1.36)2.37 (1.54-3.65) *0.99 (0.71-1.37)* p &lt; 0.05

Conclusions: LCIS diagnosed concurrently with DCIS is not associated with IBTR, but increases the risk of CBC two-fold. Endocrine therapy should be considered both for the index DCIS and for prevention of subsequent CBC.

Citation Format: Miller ME, Muhsen S, Zabor EC, Flynn J, Olcese C, Giri D, Van Zee KJ, Pilewskie M. Risk of contralateral breast cancer (CBC) in women with ductal carcinoma in situ (DCIS) with and without and synchronous lobular carcinoma in situ (LCIS) [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P5-18-01.

Modeling nicotine regulation: A review of studies in smokers with mental health conditions

Smokers with mental health conditions (MHCs) lose approximately 15 years of life relative to non-smokers without MHCs, of which two-thirds are attributable to smoking. The Food and Drug Administration (FDA) recently announced a new regulatory strategy for tobacco that includes a reduction in the nicotine content of cigarettes sold in the US to a minimally-addictive level. This action could improve cessation rates in smokers with MHCs by reducing their dependence on nicotine. However, nicotine reduction also could have unintended negative consequences in smokers with MHCs. Thus, it is important to conduct randomized controlled trials to investigate the potential effects of nicotine reduction in smokers with MHCs. Several studies of the acute or extended effects of nicotine reduction in smokers with emotional disorders or serious mental illness have been recently completed or are underway. Studies to date indicate that when smokers with MHCs are switched, under randomized, double-blind conditions, to cigarettes with very low nicotine content, they reduce their cigarette intake, with minimal or no effects on withdrawal, psychiatric symptoms, or compensatory smoking. However, some deleterious effects of nicotine reduction on cognitive performance measures in smokers with schizophrenia have been observed, which are offset by providing concurrent nicotine replacement. We review these studies and provide suggestions for potentially increasing the effectiveness of a nicotine reduction strategy for reducing smoking in people with MHCs. The research described was conducted in the United States in 2010-2018.

Response to reduced nicotine content cigarettes among smokers differing in tobacco dependence severity

This study examines whether tobacco dependence severity moderates the acute effects of reducing nicotine content in cigarettes on the addiction potential of smoking, craving/withdrawal, or smoking topography. Participants (N = 169) were daily smokers with mild, moderate, or high tobacco-dependence severity using the Heaviness of Smoking Index. Following brief abstinence, participants smoked research cigarettes varying in nicotine content (0.4, 2.4, 5.2, 15.8 mg nicotine/g tobacco) in a within-subject design. Results were analyzed using repeated measures analysis of co-variance. No main effects of dependence severity or interactions with nicotine dose were noted in relative reinforcing effects in concurrent choice testing or subjective effects on the modified Cigarette Evaluation Questionnaire. Demand for smoking in the Cigarette Purchase Task was greater among more dependent smokers, but reducing nicotine content decreased demand independent of dependence severity. Dependence severity did not significantly alter response to reduced nicotine content cigarettes on the Minnesota Tobacco Withdrawal Scale nor Questionnaire of Smoking Urges-brief (QSU) Factor-2 scale; dependence severity and dose interacted significantly on the QSU-brief Factor-1 scale, with reductions dependent on dose among highly but not mildly or moderately dependent smokers. Dependence severity and dose interacted significantly on only one of six measures of smoking topography (i.e., maximum flow rate), which increased as dose increased among mildly and moderately but not highly dependent smokers. These results suggest that dependence severity has no moderating influence on the ability of reduced nicotine content cigarettes to lower the addiction potential of smoking, and minimal effects on relief from craving/withdrawal or smoking topography.

Posttraumatic stress disorder and tobacco use: A systematic review and meta-analysis

Posttraumatic stress disorder (PTSD) and tobacco use are prevalent conditions that co-occur at striking rates in the US. Previous reviews examined prevalence and factors associated with cigarette smoking among individuals with PTSD but have not been summarized since 2007. Moreover, none explored rates and factors associated with the use of other tobacco products. This study aimed to systematically review the most recent literature examining the comorbidity of PTSD and tobacco use to provide prevalence rates, as well as summarize the literature exploring other factors associated with tobacco use among individuals with PTSD. Studies were identified using a systematic search of keywords related to tobacco use and PTSD within the following databases: PubMed, PsycINFO, Web of Knowledge, CINAHL, PsycARTICLES, and Cochrane Clinical Trials Library. The studies included in this review (N = 66) showed that the prevalence of current use of tobacco products in individuals with PTSD was 24.0% and the rate of PTSD among users of tobacco products was 20.2%. Additionally, results demonstrated that individuals with PTSD present with high levels of nicotine dependence and heavy use of tobacco products, as well as underscore the importance of negative emotional states as a contributing factor to tobacco use among individuals with PTSD. It is imperative that future studies continue monitoring tobacco use among individuals with PTSD while also assessing factors identified as having a prominent role in tobacco use among individuals with PTSD. These findings also demonstrate the need for more innovative approaches to reduce the pervasive tobacco use among individuals with PTSD.

Contingency management for college student smokers: The role of drinking as a moderator and mediator of smoking abstinence during treatment

INTRODUCTION

Contingency management (CM) is effective for promoting smoking abstinence; however, moderators and mediators of CM treatment efficacy in young adult populations are under-explored. We leveraged fine-grained data from a large randomized controlled trial: 1) to determine whether early attainment of sustained abstinence mediated the effect of treatment on abstinence; 2) to test whether heavy drinking moderated the effect of treatment on abstinence; and 3) to test a serial mediation model of the effects of drinking during early treatment on sustained smoking abstinence.

METHODS

College student smokers (N=110) were randomized to receive either CM treatment or noncontingent reinforcement (NR) over a 21-day treatment period. All participants received $5 for providing twice-daily breath carbon monoxide (CO) samples. In CM, additional money was provided for samples that indicated smoking reduction (Initial Phase; first 7days), and for samples ≤5ppm (Abstinence Phase; following 14days).

RESULTS

CM treatment led to greater sustained abstinence relative to NR. Longer sustained abstinence in the Initial Phase partially mediated the effect of treatment on sustained abstinence in the Abstinence Phase. Heavier pretreatment drinkers had shorter periods of sustained abstinence in the Abstinence Phase; this effect was greater in CM. A serial mediation model determined that increased drinking during the Initial Phase led to decreased sustained abstinence, which then led to decreased sustained abstinence in the Abstinence Phase.

CONCLUSIONS

These data provide a greater understanding of how heavy drinking and early sustained abstinence may affect success during treatment in young adults undergoing contingency management treatment for smoking.

Cognitive Performance Does not Limit Physical Activity Participation in the Lifestyle Interventions and Independence for Elders Pilot Study (LIFE-P)

OBJECTIVES

We examined whether multiple domains of baseline cognitive performance were associated with prospective physical activity (PA) adherence in the Lifestyle Interventions and Independence for Elders Pilot study (LIFE-P).

DESIGN, SETTING, PARTICIPANTS

The LIFE-P study was a single-blind, multicenter, randomized controlled trial of a PA intervention compared to a successful aging educational intervention in sedentary, mobility-limited older adults.

INTERVENTION

A 12-month structured, moderate-intensity, multi-modal PA program that included walking, resistance training, and flexibility exercises. For the first 2 months (adoption), 3 center-based exercise sessions (40-60 min) / week were conducted. During the next 4 months (transition), center-based sessions were conducted 2 times / week. The subsequent maintenance phase consisted of optional once-to-twice-per-week center-based sessions and home-based PA.

MEASUREMENTS

Tests of executive and global cognitive functioning, working memory and psychomotor speed were administered at baseline. Median test scores were used to dichotomize participants into low or high cognitive performance groups.

RESULTS

52 mobility-limited older adults (age: 76.9 ±5 yrs) were randomized to the PA arm of LIFE-P. Compared to participants with high cognitive performance, participants with low performance had similar PA adherence rates (all P ≥ 0.34). Furthermore, weak and non-significant univariate relationships were elicited between all measures of cognition and overall PA adherence levels (r values ranged: -0.20 to 0.12, P ≥ 0.12).

CONCLUSION

These data suggest that cognitive performance does not limit long-term PA adherence in mobility-limited older adults. Additional studies in larger cohorts are warranted to verify these findings.

Addiction Potential of Cigarettes With Reduced Nicotine Content in Populations With Psychiatric Disorders and Other Vulnerabilities to Tobacco Addiction

IMPORTANCE

A national policy is under consideration to reduce the nicotine content of cigarettes to lower nicotine addiction potential in the United States.

OBJECTIVE

To examine how smokers with psychiatric disorders and other vulnerabilities to tobacco addiction respond to cigarettes with reduced nicotine content.

DESIGN, SETTING, AND PARTICIPANTS

A multisite, double-blind, within-participant assessment of acute response to research cigarettes with nicotine content ranging from levels below a hypothesized addiction threshold to those representative of commercial cigarettes (0.4, 2.3, 5.2, and 15.8 mg/g of tobacco) at 3 academic sites included 169 daily smokers from the following 3 vulnerable populations: individuals with affective disorders (n = 56) or opioid dependence (n = 60) and socioeconomically disadvantaged women (n = 53). Data were collected from March 23, 2015, through April 25, 2016.

INTERVENTIONS

After a brief smoking abstinence, participants were exposed to the cigarettes with varying nicotine doses across fourteen 2- to 4-hour outpatient sessions.

MAIN OUTCOMES AND MEASURES

Addiction potential of the cigarettes was assessed using concurrent choice testing, the Cigarette Purchase Task (CPT), and validated measures of subjective effects, such as the Minnesota Nicotine Withdrawal Scale.

RESULTS

Among the 169 daily smokers included in the analysis (120 women [71.0%] and 49 men [29.0%]; mean [SD] age, 35.6 [11.4] years), reducing the nicotine content of cigarettes decreased the relative reinforcing effects of smoking in all 3 populations. Across populations, the 0.4-mg/g dose was chosen significantly less than the 15.8-mg/g dose in concurrent choice testing (mean [SEM] 30% [0.04%] vs 70% [0.04%]; Cohen d = 0.40; P < .001) and generated lower demand in the CPT (α = .027 [95% CI, 0.023-0.031] vs α = .019 [95% CI, 0.016-0.022]; Cohen d = 1.17; P < .001). Preference for higher over lower nicotine content cigarettes could be reversed by increasing the response cost necessary to obtain the higher dose (mean [SEM], 61% [0.02%] vs 39% [0.02%]; Cohen d = 0.40; P < .001). All doses reduced Minnesota Nicotine Withdrawal Scale total scores (range of mean decreases, 0.10-0.50; Cohen d range, 0.21-1.05; P < .001 for all), although duration of withdrawal symptoms was greater at higher doses (η2 = 0.008; dose-by-time interaction, P = .002).

CONCLUSIONS AND RELEVANCE

Reducing the nicotine content of cigarettes may decrease their addiction potential in populations that are highly vulnerable to tobacco addiction. Smokers with psychiatric conditions and socioeconomic disadvantage are more addicted and less likely to quit and experience greater adverse health impacts. Policies to reduce these disparities are needed; reducing the nicotine content in cigarettes should be a policy focus.

Response to varying the nicotine content of cigarettes in vulnerable populations: an initial experimental examination of acute effects

RATIONALE

The purpose of this study was to begin researching the effects of very low nicotine content cigarettes in smokers especially vulnerable to dependence to assess their potential as a less dependence-producing alternative to current commercial cigarettes.

METHODS

Participants were 26 adult, daily cigarette smokers from one of three populations: economically disadvantaged women of reproductive age (n = 9), opioid-dependent individuals (n = 11), and individuals with affective disorders (n = 6). Participants completed fourteen 2-4-h experimental sessions in a within-subjects research design. Sessions were conducted following brief smoking abstinence. Four research cigarettes varying in nicotine content (0.4, 2.4, 5.2, and 15.8 mg/g) were studied under double-blind conditions, assessing smoking topography, subjective effects, and relative reinforcing effects of varying doses in concurrent choice tests. Results were collapsed across vulnerable populations and analyzed using repeated measures ANOVA.

RESULTS

No significant differences between doses were discernible in smoking topography. All doses were equi-effective at reducing nicotine withdrawal. Ratings of satisfaction from smoking were lower at the 0.4 compared to 15.8 mg/g dose. Participants preferred the 15.8 mg/g dose over the 0.4 and 2.4 but not the 5.2 mg/g doses in concurrent choice testing; no differences between the two lowest doses were noted.

CONCLUSIONS

All cigarettes effectively reduced nicotine withdrawal with no differences in smoking topography, suggesting minimal compensatory smoking. Dependence potential was lowest at the 0.4 mg/g dose. These initial results are promising regarding the feasibility of lowering nicotine content in cigarettes to very low levels in vulnerable populations without untoward effects.

Smoking Topography Characteristics of Very Low Nicotine Content Cigarettes, With and Without Nicotine Replacement, in Smokers With Schizophrenia and Controls

INTRODUCTION

Reducing the nicotine content of cigarettes to a minimally addictive level has been proposed as a regulatory strategy for reducing tobacco dependence. However, smokers with schizophrenia (SS) may be prone to changing their smoking topography in efforts to compensate for the reduction in nicotine content. The aims of this study were to compare smoking topography characteristics of usual-brand and very low nicotine content (VLNC) cigarettes in SS and control smokers without psychiatric illness (CS), and to determine whether nicotine replacement reversed any changes in topography produced by VLNC cigarettes.

METHODS

Using a within-subjects, counter-balanced design, SS (n = 27) and CS (n = 23) smoked usual brand cigarettes, VLNC cigarettes while wearing placebo patches (VLNC + PLA), or VLNC cigarettes while wearing transdermal nicotine patches totaling 42mg (VLNC + NIC) during 5-hour ad libitum smoking sessions. Cigarettes were smoked through topography measurement devices.

RESULTS

Across conditions, SS smoked more puffs per session and per cigarette, had higher cigarette volumes, and had shorter inter-puff intervals than CS (Ps < .01). During VLNC cigarette sessions, puff duration increased and time between puffs decreased, but participants smoked fewer puffs, resulting in a net decrease in cigarette and total session volume (Ps < .001). There were no significant interactions between group and condition.

CONCLUSIONS

These findings indicate that acute use of VLNC cigarettes does not increase intensity of smoking in SS, and support the feasibility of a nicotine reduction policy.

IMPLICATIONS

Reducing the nicotine in cigarettes to a minimally addictive level has been proposed as a means of reducing tobacco dependence. However, smokers, particularly those with schizophrenia (SS) may alter their puffing in an attempt to extract more nicotine from VLNC cigarettes. This study compared smoking topography of usual brand versus VLNC cigarettes, combined with placebo or transdermal nicotine patches, in SS and controls. Although some changes in topography were indicative of compensatory smoking, total puffs and total cigarette volume were reduced with VLNC cigarettes, indicating that acute VLNC cigarette use does not increase smoking in SS.

Biomarkers associated with severe hypoglycaemia and death in ACCORD

AIMS AND HYPOTHESIS

In patients with Type 2 diabetes, intensive glycaemic control is associated with hypoglycaemia and possibly increased mortality. However, no blood biomarkers exist to predict these outcomes. Using participants from the Action to Control Cardiovascular Risk in Diabetes (ACCORD) study, we hypothesized that insulin deficiency and islet autoantibodies in patients with clinically diagnosed Type 2 diabetes would be associated with severe hypoglycaemia and death.

METHODS

A nested case-control study design was used. A case (n = 86) was a participant who died with at least one episode of severe hypoglycaemia, defined as hypoglycaemia requiring assistance, at any point during ACCORD follow-up. A control (n = 344) was a participant who did not die and did not have severe hypoglycaemia during follow-up. Each case was matched to four controls (glycaemic intervention arm, race, age and BMI). Baseline insulin deficiency (fasting C-peptide ≤ 0.15 nmol/l) and islet autoantibodies [glutamic acid decarboxylase (GAD), tyrosine phosphatase-related islet antigen 2 (IA2), insulin (IAA) and zinc transporter (ZnT8)] were measured. Conditional logistic regression with and without adjustment for age, BMI and diabetes duration was used.

RESULTS

Death during ACCORD in those who experienced at least one episode of severe hypoglycaemia was associated with insulin deficiency [OR 4.8 (2.1, 11.1): P < 0.0001], GAD antibodies [OR 2.3 (1.1, 5.1): P = 0.04], the presence of IAA or baseline insulin use [OR 6.1 (3.5,10.7): P < 0.0001], which remained significant after adjusting for age, BMI, and diabetes duration. There was no significant association with IA2 or ZnT8 antibodies.

CONCLUSIONS

In patients with Type 2 diabetes, C-peptide or GAD antibodies may serve as blood biomarkers predicting higher odds of subsequent severe hypoglycaemia and death. (Clinical Trial Registry No: NCT00000620, www.clinicaltrials.gov for original ACCORD study).

Financial incentives to promote extended smoking abstinence in opioid-maintained patients: a randomized trial

BACKGROUND AND AIMS

Prior studies by our group demonstrated the efficacy of a brief but intensive behavioral intervention for producing initial smoking abstinence among opioid-dependent patients. In the present study, our aim was to promote longer-duration abstinence in this population. Following an initial 2-week incentive intervention for smoking abstinence, we examined whether a 10-week maintenance arm involving continuation of contingent reinforcement will produce greater smoking abstinence than a similar duration of noncontingent reinforcement.

DESIGN

Randomized, 12-week, parallel-group study.

SETTING

Out-patient research clinic in Burlington, Vermont, USA.

PARTICIPANTS

Opioid-maintained smokers (n = 88) who provided breath carbon monoxide and urinary cotinine specimens and received contingent reinforcement for smoking abstinence during weeks 1-2 (phase 1), with 63 randomized on day 14 to an extended contingent (EC; n = 31) or extended noncontingent (EN; n = 32) experimental condition for weeks 3-12 (phase 2).

INTERVENTION AND CONTROL

The EC condition consisted of voucher values that escalated across consecutive negative samples until they reached $30, after which they remained at $30 per negative sample. A positive or a missing sample resulted in no vouchers for that day and reset the value of the next negative same to $9. Two consecutive negatives returned the schedule to the pre-reset value. The EN control condition consisted of vouchers delivered for providing scheduled samples, but independent of smoking status.

MEASUREMENTS

The primary outcome was percentage of biochemically abstinent samples during phase 2. Secondary measures included abstinence status at final study visit, complete abstinence, participants' longest duration of continuous abstinence, cotinine and carbon monoxide (CO) levels and self-reported cigarettes per day.

FINDINGS

EC participants achieved greater smoking abstinence during phase 2 than EN participants [46.7 versus 23.5% negative samples, respectively; odds ratio (OR) = 2.98, 95% confidence interval (CI) = 1.16-7.65, χ(2) 1  (=)  5.0, P = 0.02]. When longest duration of continuous abstinence was compared between experimental groups, EC participants achieved twice the mean duration of continuous abstinence compared with EN participants (3.31 versus 1.68 weeks; t61  = 1.83, P = 0.07). An effect of experimental condition was also seen on mean cotinine levels (42.5 versus 210.6 ng/ml, respectively; F1,61 =5.9, P = 0.02).

CONCLUSIONS

Among opioid-maintained smokers receiving an initial period of daily contingent incentives, a contingent reinforcement intervention appears to be more effective at extending smoking abstinence than noncontingent reinforcement over 10 weeks.

Toward a clinical application of ex situ boron neutron capture therapy for lung tumors at the RA-3 reactor in Argentina

PURPOSE

Many types of lung tumors have a very poor prognosis due to their spread in the whole organ volume. The fact that boron neutron capture therapy (BNCT) would allow for selective targeting of all the nodules regardless of their position, prompted a preclinical feasibility study of ex situ BNCT at the thermal neutron facility of RA-3 reactor in the province of Buenos Aires, Argentina. (l)-4p-dihydroxy-borylphenylalanine fructose complex (BPA-F) biodistribution studies in an adult sheep model and computational dosimetry for a human explanted lung were performed to evaluate the feasibility and the therapeutic potential of ex situ BNCT.

METHODS

Two kinds of boron biodistribution studies were carried out in the healthy sheep: a set of pharmacokinetic studies without lung excision, and a set that consisted of evaluation of boron concentration in the explanted and perfused lung. In order to assess the feasibility of the clinical application of ex situ BNCT at RA-3, a case of multiple lung metastases was analyzed. A detailed computational representation of the geometry of the lung was built based on a real collapsed human lung. Dosimetric calculations and dose limiting considerations were based on the experimental results from the adult sheep, and on the most suitable information published in the literature. In addition, a workable treatment plan was considered to assess the clinical application in a realistic scenario.

RESULTS

Concentration-time profiles for the normal sheep showed that the boron kinetics in blood, lung, and skin would adequately represent the boron behavior and absolute uptake expected in human tissues. Results strongly suggest that the distribution of the boron compound is spatially homogeneous in the lung. A constant lung-to-blood ratio of 1.3 ± 0.1 was observed from 80 min after the end of BPA-F infusion. The fact that this ratio remains constant during time would allow the blood boron concentration to be used as a surrogate and indirect quantification of the estimated value in the explanted healthy lung. The proposed preclinical animal model allowed for the study of the explanted lung. As expected, the boron concentration values fell as a result of the application of the preservation protocol required to preserve the lung function. The distribution of the boron concentration retention factor was obtained for healthy lung, with a mean value of 0.46 ± 0.14 consistent with that reported for metastatic colon carcinoma model in rat perfused lung. Considering the human lung model and suitable tumor control probability for lung cancer, a promising average fraction of controlled lesions higher than 85% was obtained even for a low tumor-to-normal boron concentration ratio of 2.

CONCLUSIONS

This work reports for the first time data supporting the validity of the ovine model as an adequate human surrogate in terms of boron kinetics and uptake in clinically relevant tissues. Collectively, the results and analysis presented would strongly suggest that ex situ whole lung BNCT irradiation is a feasible and highly promising technique that could greatly contribute to the treatment of metastatic lung disease in those patients without extrapulmonary spread, increasing not only the expected overall survival but also the resulting quality of life.

Are Pharmacotherapies Ineffective in Opioid-Dependent Smokers? Reflections on the Scientific Literature and Future Directions

While rates of smoking in the general population have decreased in recent years, dramatic disparities remain among disadvantaged subgroups of smokers, particularly those with concurrent substance abuse. Prevalence rates of smoking among opioid-dependent patients, for example, are fourfold those of the general population. While pharmacotherapies are recommended as a first-line treatment for nicotine dependence, the few studies that have investigated their effectiveness in this population have shown dramatically poorer outcomes compared to the general population. Indeed, these findings have led some researchers to suggest that pharmacotherapies may simply be ineffective in opioid-maintained smokers. In this commentary, we briefly summarize the extant literature on pharmacotherapies in opioid-maintained smokers and contribute new data investigating the contribution of bupropion on smoking outcomes in 81 methadone- and buprenorphine-maintained participants from two randomized trials of financial incentives for smoking cessation. We also discuss several important parameters (ie, timing of the quit attempt, medication adherence, nicotine withdrawal) that may be leveraged to strengthen smoking pharmacotherapy outcomes in opioid-dependent patients. Taken together, an improved understanding of these issues will aid efforts to reduce tobacco-related health disparities in this group of challenging smokers.

A literature review on prevalence of gender differences and intersections with other vulnerabilities to tobacco use in the United States, 2004-2014

This report describes results from a systematic literature review examining gender differences in U.S. prevalence rates of current use of tobacco and nicotine delivery products and how they intersect with other vulnerabilities to tobacco use. We searched PubMed on gender differences in tobacco use across the years 2004-2014. For inclusion, reports had to be in English, in a peer-reviewed journal or federal government report, report prevalence rates for current use of a tobacco product in males and females, and use a U.S. nationally representative sample. Prevalence rates were generally higher in males than in females across all products. This pattern remained stable despite changes over time in overall prevalence rates. Gender differences generally were robust when intersecting with other vulnerabilities, although decreases in the magnitude of gender differences were noted among younger and older users, and among educational levels and race/ethnic groups associated with the highest or lowest prevalence rates. Overall, these results document a pervasive association of gender with vulnerability to tobacco use that acts additively with other vulnerabilities. These vulnerabilities should be considered whenever formulating tobacco control and regulatory policies.

Smoking cessation and reduction in people with chronic mental illness

The high prevalence of cigarette smoking and tobacco related morbidity and mortality in people with chronic mental illness is well documented. This review summarizes results from studies of smoking cessation treatments in people with schizophrenia, depression, anxiety disorders, and post-traumatic stress disorder. It also summarizes experimental studies aimed at identifying biopsychosocial mechanisms that underlie the high smoking rates seen in people with these disorders. Research indicates that smokers with chronic mental illness can quit with standard cessation approaches with minimal effects on psychiatric symptoms. Although some studies have noted high relapse rates, longer maintenance on pharmacotherapy reduces rates of relapse without untoward effects on psychiatric symptoms. Similar biopsychosocial mechanisms are thought to be involved in the initiation and persistence of smoking in patients with different disorders. An appreciation of these common factors may aid the development of novel tobacco treatments for people with chronic mental illness. Novel nicotine and tobacco products such as electronic cigarettes and very low nicotine content cigarettes may also be used to improve smoking cessation rates in people with chronic mental illness.

Predicted Impact of Nicotine Reduction on Smokers with Affective Disorders

OBJECTIVES

In 2009 the FDA acquired the authority to reduce the nicotine content in cigarettes if appropriate for public health, prompting research to evaluate the implications of this policy scientifically. Studies in non-psychiatric populations show that reducing the nicotine content of cigarettes to non-addictive levels reduces smoking rates and nicotine dependence. However, few studies have examined this hypothesis in vulnerable populations.

METHODS

In this narrative review we examined the extant literature on the effects of nicotine reduction or cessation on symptoms of withdrawal, as well as psychiatric symptoms, among those with affective disorders.

RESULTS

Following initial withdrawal from nicotine, smokers with affective disorders experience more severe mood disruption than smokers without these disorders. Use of very low nicotine content (VLNC) cigarettes during abstinence may help mitigate the mood-disrupting effects of initial abstinence. Once the initial effects of nicotine withdrawal on mood have passed, longer-term abstinence is associated with psychiatric improvement rather than worsening.

CONCLUSIONS

These findings suggest that if a national nicotine reduction policy were to be implemented, smokers with affective disorders would need additional support to overcome initial withdrawal but that long-term outcomes would likely be positive.

Characterizing opioid withdrawal during double-blind buprenorphine detoxification

BACKGROUND

Prescription opioid (PO) abuse has become an urgent public health issue in the United States. Detoxification is one important treatment option, yet relatively little is known about the time course and severity of opioid withdrawal during buprenorphine detoxification.

METHODS

This is a secondary analysis of data from a randomized, placebo-controlled, double-blind evaluation of 1, 2, and 4-week outpatient buprenorphine tapers among primary prescription opioid (PO) abusers. The aim is to characterize the time course and severity of buprenorphine withdrawal under rigorous, double-blind conditions, across multiple taper durations, and using multiple withdrawal-related measures (i.e., self-report and observer ratings, pupil diameter, ancillary medication utilization). Participants were PO-dependent adults undergoing buprenorphine detoxification and biochemically-verified to be continuously abstinent from opioids during their taper (N = 28).

RESULTS

Participants randomly assigned to the 4-week taper regimen experienced a relatively mild and stable course of withdrawal, with few peaks in severity. In contrast, the 1- and 2-week taper groups experienced stark increases in withdrawal severity during the week following the last buprenorphine dose, followed by declines in withdrawal severity thereafter. The 4-week taper group also reported significantly fewer disruptions in sleep compared to the other experimental groups. When predictors of withdrawal were examined, baseline ratings of "Expected Withdrawal Severity" was the most robust predictor of withdrawal experienced during the taper.

CONCLUSION

Data from this trial may inform clinicians about the expected time course, magnitude, and pattern of buprenorphine withdrawal and aid efforts to identify patients who may need additional clinical support during outpatient buprenorphine detoxification.

Identifying information needs among children and teens living with haemophilia

Transitioning from one life stage to the next can be difficult, but for those living with a chronic condition, it can be even more challenging. Children and adolescents with haemophilia need help to manage transitions while dealing with the complications of their disorder. The National Haemophilia Foundation (NHF), headquartered in New York City, has an extensive information centre on bleeding disorders, but it was not clear how much material existed on the topic of transition. The objectives of this project were to (i) assess the availability of literature about transition for children and adolescents living with haemophilia, (ii) determine which transition issues were the most relevant and (iii) develop and test information products that would address those transition issues. An inventory of NHF's resources and an environmental scan over the Internet was performed. Focus groups were conducted to determine messaging. Video prototypes containing messages were created, tested by focus groups and revised. The literature search yielded limited information available on transition for children and adolescents with haemophilia. Results of the formative research indicated that adolescents wanted more information on sports participation and disclosure of their condition (e.g. to peers, teachers, coaches, health care providers). Video was found to be the preferred delivery format. Children and adolescents living with haemophilia need information to help them transition through life. As a result of this study, two educational products were produced, but several more are recommended to guide these individuals in making healthy transitions into adulthood.

Intracochlear schwannoma presenting as diffuse cochlear enhancement: diagnostic challenges of a rare cause of deafness

Intracochlear schwannoma is a rare, treatable, cause of unilateral hearing loss. Due to the small size, position, and variable clinical and imaging features, diagnosis presents a significant challenge and is often delayed. We present a case of a patient with an intracochlear schwannoma presenting as a diffuse enhancement of the cochlea, mimicking an infectious or inflammatory process. The absence of focal nodularity in this lesion on multiple high-resolution MRI examinations led to a delay of over 3 years from the patient's initial presentation to surgical diagnosis. Clinical history and examination, imaging features, pathologic findings, and surgical management options are described.

Expression and characterization of a multivalent human respiratory syncytial virus protein

Respiratory syncytial virus (RSV) has been recognized as one of the most common causes of severe respiratory tract infection in infants worldwide. As yet, a safe and effective vaccine has not been developed to protect humans from RSV. The F and G surface proteins have been widely investigated due to their potential to induce protective immunity. In addition, the M2 protein has been shown to be important in inducing a T-cell response. Our project involved the cloning of the immunodominant regions of the RSV F, M2 and G proteins into a bacterial vector, pET-32a (+). The recombinant RFM2G protein was expressed in Escherichia coli and purified using His Bind columns. The purified rRFM2G protein was analyzed by polyacrylamide gel electrophoresis and Western blotting. The predicted structure of the recombinant protein built by the Swiss PDB Viewer program suggested a rod shape with a distinct swollen head and neck which was confirmed by transmission electron microscopy and atomic force microscopy. BALB/c female mice were immunized with either RSV, rRFM2G alone, or rRFM2G in combination with flagellin as a mucosal adjuvant. Serum was collected on days 0, 14, 28 and 49 to assess the immune response by Enzyme-linked immunosorbent assay. Intranasal immunization of mice with the rRFM2G protein yielded significantly high serum IgG titers. Co-administration of the rRFM2G protein with flagellin did not augment the serum antibody response.

HIV risk exposure of injecting drug users in Sydney

One thousand two hundred and forty-five Sydney injecting drug users (IDUs) were interviewed by questionnaire in 1989 to determine demographic and behavioural characteristics. One-sixth (16.7%) were considered to be at low risk of HIV from either needle sharing or sexual transmission as they had either never shared injecting equipment, or had not shared for years, or cleaned their injecting equipment effectively on 100% of the occasions when they did share; and were either celibate or monogamous or, if they had multiple partners, had not had unsafe sex in the previous 6 months. Over half (50.7%) had either unsafe injecting or sexual behaviour with the remaining third (32.6%) engaging in both unsafe injecting and sexual practises. Women were more at risk from sharing injection equipment than men but men were more at risk from sexual transmission than women. Increasing age was associated with greater likelihood of safer sex but age had no effect on injecting practises. There was no relationship between unsafe injecting and sexual practises. Amphetamine use was associated with low risk injecting practises while heroin use was associated with low risk sexual transmission. These findings indicate appreciable residual risk behaviour sufficient to allow for at least a slow diffusion of HIV among injecting drug users.

Predictors of unsafe injecting drug use

This paper reports on the incidence of unsafe injecting and the factors which influence this practice in a sample of 1245 Sydney injecting drug users (IDUs). Using a needle and syringe after someone else at some time in the last six months was reported in 41.6% of the sample. Taking into account those who claimed always to clean used needles with virucidal methods, 32.9% had placed themselves at risk of HIV infection from shared needles in the six months prior to interview.Seven factors were predictive of unsafe behaviour. These were (a) the amount spent per week on drugs, (b) the number of times a single needle was used prior to disposal, (c) having shared with a person who is now HIV infected, (d) having a regular sexual partner, (e) the proportion of times high, stoned or drunk when injecting, (f) being part of a group that injects together and (g) having been in prison.

Estimation of bone strength from pediatric radiographs of the forearm

OBJECTIVE

Bone strength is a function of both material and architectural properties. However, bone geometry or architecture, which determines the distribution of bone, is an underappreciated determinant of bone strength. The aim of the study was to evaluate the contribution of only architecture to bone strength.

METHODS

We used 2-D (planar) geometric information from radiographs of human radii to construct 3-D finite-element models. To transition from 2-D to 3-D (volume) space, we assumed that all bone cross-sections were elliptical in shape. The finite-element models were subjected to cantilever loading to determine the locations in the bone with the highest propensity to fracture (points of maximum stress). The finite-element-analysis results of the models generated from radiographs of both normal (18) and temporary-brittle-bone-disease (11) infants were subjected to a receiver operating curve analysis. The area under the receiver operating curve was used to evaluate the power of a given bone-strength indicator in segregating the two populations. The actual choice of the material properties (Young's modulus or Poisson's ratio) was not critical for this study, since the finite element analyses were designed to capture the difference in the bone strength of the two populations only based on their architecture. Therefore, the material properties were assumed to be the same in both the normal and TBBD populations.

RESULTS

The area under the curve of the bending load required to cause fracture among the two populations was 0.82. Other bone-strength indicators, such as average section modulus, cortical thickness and bone length, were associated with an area under the curve of 0.75, 0.73 and 0.63, respectively.

CONCLUSION

The results of the finite-element-analysis suggest that the temporary-brittle-bone-disease population has an altered bone geometry, which increases susceptibility to fracture under normal bending loads.

First Report of Iris yellow spot virus on Onion (Allium cepa) in Texas

Iris yellow spot virus (IYSV; family Bunyaviridae, genus Tospovirus) has emerged as a potentially devastating and widespread virus of onion. IYSV was first reported in the United States from Idaho in 1993 and has since spread to many of the onion-producing areas (1). In South America, the most recent reports of the virus on onion were from Peru and Chile (2,4). In 2005, onion plants in Uvalde County, Texas exhibited necrotic lesions on leaves typical of IYSV and disease incidence approached 100% in some fields with yield loss and quality problems. Five of six plants tested were positive for IYSV with double antibody sandwich-enzyme linked immunosorbent assay (DAS-ELISA; Agdia Inc., Elkhart, IN). In 2006, similar lesions were observed on onion plants in Uvalde County and approximately 400 km south in Hidalgo and Cameron counties. Infection points generally started as a single plant near the edge of fields and spread to plants in a 3- to 4-m area after 1 to 2 weeks. Early-season disease incidence was low in onions grown for bulbs and transplants, <10% in 2006. Disease incidence increased in some fields until the crop was harvested. Leaves of symptomatic plants were tested for IYSV and Tomato spotted wilt virus (TSWV) using DAS-ELISA, and 18 of 23 samples from the Hidalgo County area and 12 of 21 samples from the Uvalde County area were positive for IYSV. All samples tested for TSWV from these counties were negative. Virus infection in some ELISA-positive plants was verified by reverse transcription-polymerase chain reaction (RT-PCR) using primers derived from the small RNA of IYSV. The primers flanked the IYSV nucleocapsid (N) gene (5'-TAA AAC AAA CAT TCA AAC AA-3' and 5'-CTC TTA AAC ACA TTT AAC AAG CAC-3' (3). RT-PCR gave a PCR product of expected size (approximately 1.2 kb). The DNA amplicon was cloned and sequenced (GenBank Accession No. DQ658242). Nucleotide sequence analysis confirmed the identity of the amplicon as that of IYSV N gene and sequence comparisons with known IYSV N gene sequences showed 95 to 98% sequence identity. The primary vector of IYSV, onion thrips (Thrips tabaci), is a widespread and destructive pest of onion in south Texas. The year-to-year incidence of IYSV and the severity of the disease will probably depend on the onion thrips population levels. Bulb yield reduction could be severe during years with high thrips populations. More research is needed to determine the impact of IYSV on bulb yield in Texas, the relationship between IYSV incidence and T. tabaci population levels, and oversummering hosts. To our knowledge, this is the first known report of IYSV in Texas. References: (1) D. H. Gent et al. Plant Dis. 88:446, 2004, (2) S. W. Mullis et al. Plant Dis. 90:377, 2006, (3) H. Pappu et al. Arch. Virol. 151:1015, 2006. (4) M. Rosales et al. Plant Dis. 89:1245, 2005.

First Report of Rust Caused by Phakopsora pachyrhizi on Soybean and Kudzu in Texas

The Asian soybean rust fungus, Phakopsora pachyrhizi H. Sydow & Sydow, was found on a 0.4-ha patch of kudzu (Pueraria lobata) near Dayton (Liberty County) in East Texas on November 2, 2005. Nearly 100% of the 300 leaflets examined were diseased with severity ranging from 5 to >100 lesions per leaflet. Eleven soybean fields as much as 20 km away were scouted and no infected plants were found. Asian soybean rust was also found on a 0.4-ha field of soybean (Glycine max cv. Vernal) on February 14, 2006 at the Texas A&M Agricultural Experiment Station in Weslaco (Hidalgo County) in the Lower Rio Grande Valley (LRGV) of Texas. Disease incidence was 100% (severity ranging from 5 to >100 lesions per leaflet) on 50 younger plants with green leaves along the edges of the field, whereas most of the plants in this field had senesced. These plants were not symptomatic and were at the R6 stage (full seed) when this field was previously scouted on December 19, 2005. Lesions on leaflets of kudzu and soybean were small and angular with erumpent uredinia typical of P. pachyrhizi. Urediniospores were ovoid or globose, hyaline, and measured 25 to 30 × 14 to 21 μm. Leaf samples with pustules were positive for P. pachyrhizi using enzyme-linked immunosorbent assay (ELISA) (Envirologix, Portland, ME). Morphological and polymerase chain reaction (PCR) identification of P. pachyrhizi from kudzu and soybean samples were confirmed by the USDA-APHIS-PPQ NIS and CPHST laboratories in Beltsville, MD as previously described (2). The kudzu in East Texas is not likely to support overwintering of the pathogen because it usually dies back during the winter. Leaves at this site were dead by January 17, 2006. This is the southernmost infestation of kudzu in Texas known to us. In contrast, the LRGV has a subtropical climate that would favor year-round survival of the fungus (3). This area, where 120 to 160 ha of soybeans are grown, may be a source of inoculum for soybean rust epidemics in the Midwest. Spore movement would follow the same pattern as seen with cereal rusts (1). However, soybeans are typically absent from the LRGV between late December and early March, so survival of the fungus during this interval would require other hosts. Regardless of whether the fungus overwinters here, or moves in from elsewhere, the LRGV spring crop could serve as an early indicator of a potential rust epidemic. References: (1) M. G. Eversmeyer and C. L. Kramer. Annu. Rev. Phytopathol. 38:491, 2000. (2) J. M. Mullen et al. Plant Dis. 90:112, 2006. (3) S. Pivonia et al. Plant Dis. 89:678, 2005.

Benzo-[a]-pyrene increases invasion in MDA-MB-231 breast cancer cells via increased COX-II expression and prostaglandin E2 (PGE2) output

Benzo-[a]-pyrene (B[a]P), a carcinogenic component of cigarette smoke, has been shown to increase both COX-II expression and prostaglandin output in vascular smooth muscle and oral epithelial cells. In addition, invasive breast cancer cells have been reported to over express COX-II and PGE(2). Therefore, the objective of this study was to quantify the effect of increasing B[a]P concentrations on COX-II expression, PGE(2) output, and invasion using MDA-MB-231 cells, an invasive estrogen unresponsive breast cancer cell line. B[a]P significantly increased invasion in MDA-MB-231 cells at concentrations greater than 4 x 10(-8) M. Treatment of MDA-MB-231 cells with Vomitoxin (a selective COX-II inducer) enhanced invasion whereas co-treatment with NS398 (a selective COX-II inhibitor) attenuated B[a]P-induced invasion in MDA-MB-231 cells. Immunohistochemical staining and Western blots demonstrated a significant B[a]P treatment-induced increase in both the number of COX-II immunopositive MDA-MB-231 cells and COX-II protein levels. Moreover, B[a]P-treatment induced a profound (46 fold) increase in PGE(2) production by MDA-MB-231 cells. The aryl hydrocarbon receptor (AhR) antagonists resveratrol (RES) and alpha-naphthaflavone (alpha-NF) had no effect on their own, whereas B[a]P-induced invasion was significantly inhibited by co-treatment with RES and alpha-NF. Our data demonstrate that B[a]P-induced changes in invasion are mediated through augmented COX-II expression and PGE(2) production involving an AhR regulated pathway. Moreover, these results suggest a potential role for the AhR signalling pathway in breast cancer invasion.

Implantable self-powered detector for on-line determination of neutron flux in patients during NCT treatment

A novel system to determine thermal neutron flux in real time during NCT treatments was developed in the National Atomic Energy Commission of Argentina. The system is based on a special self-powered detector that can be implanted in patients owing to its small size and biocompatibility. High voltage is not required to operate this kind of detectors, which is a considerable advantage in terms of medical uses. By choosing the appropriate materials, it was possible to obtain a prototype with thermal neutron sensitivity providing for an adequate signal level in typical NCT thermal fluxes. It was also possible to minimize gamma response in order to neglect its contribution.

Cellular basis of diabetic nephropathy: III. In vitro GLUT1 mRNA expression and risk of diabetic nephropathy in type 1 diabetic patients

AIMS/HYPOTHESIS

Altered glucose transporter expression has been implicated in the pathogenesis of diabetic nephropathy. There is increasing evidence that genetic factors convey risk of, or protection from, diabetic nephropathy and that the behaviour of cultured skin fibroblasts from type 1 diabetic patients may reflect these genetic influences. This study aimed to compare GLUT1 mRNA expression levels in skin fibroblasts from type 1 diabetic patients with either rapid ("fast-track", n=25) or slow ("slow-track", n=25) development of diabetic nephropathy and from non-diabetic normal control subjects (controls, n=25).

METHODS

Skin fibroblasts were cultured in Dulbecco's Modified Eagle's Medium with 25 mmol/l glucose for 36 h. Total RNA was isolated, and GLUT1 mRNA levels were estimated by microarray analysis and RT-PCR.

RESULTS

Levels of GLUT1 mRNA expression in skin fibroblasts from "slow-track" patients were greater than those from "fast-track" patients (p=0.02), as initially detected by microarray. GLUT1 mRNA expression levels were confirmed by RT-PCR to be higher in skin fibroblasts from "slow-track" patients (4.59+/-2.04) than in those from "fast-track" patients (3.34+/-1.2, p=0.02), and were also higher than in skin fibroblasts from control subjects (3.52+/-1.66, p=0.03). There was no statistically significant difference between levels of expression in the "fast-track" patients and the control subjects.

CONCLUSIONS/INTERPRETATION

This finding is consistent with the presence of cellular protection factors against diabetic nephropathy in the "slow-track" patients. These factors could be associated with the regulation of the GLUT1 pathway and may be genetically determined.

Improving the insecticidal activity of Bacillus thuringiensis subsp. aizawai against Spodoptera exigua by chromosomal expression of a chitinase gene

A transcriptionally fused gene comprising the P19 gene from Bacillus thuringiensis subsp. israelensis fused with a chitinase gene (chiBlA) from B. licheniformis was integrated into the B. thuringiensis subsp. aizawai BTA1 genome by homologous recombination. The resulting B. thuringiensis subsp. aizawai strain (INT1) showed growth and sporulation comparable with that of the wild-type strain. INT1 produced four chitinases of different molecular masses (i.e., 66, 55, 39, 36 kDa). Three of these (66, 55, 36 kDa) were derived from the cloned chiBlA gene, whereas the 39-kDa chitinase originated from BTA1. Using surface contamination bioassays, the 50% lethal concentration of lyophilized whole culture broth of INT1 against Spodoptera exigua neonate larvae was 12.2 microg/cm2, compared with 30.8 microg/cm2 for BTA1. Bioassays using filtered culture supernatant of INT1 (110 microg/cm2) together with trypsin-activated purified Cry1C protein of B. thuringiensis (1,280 ng/cm2) showed 75.0% mortality, compared with 56.7% mortality for Cry1C combined with BTA1 at the same concentration. Using scanning electron microscopy, clear perforations were observed in S. exigua fifth instar peritrophic membranes incubated with either crude or purified chitinase, or isolated from fifth instar S. exigua fed purified chitinase since the first instar. These results show that chitinase can increase the activity of B. thuringiensis subsp. aizawai against S. exigua. This is the first documentation of expressing a chimeric chitinase gene on the chromosome of B. thuringiensis; and chromosomal integration might be used as a potential technique for strain improvement.

Oxytocin does not directly affect vascular tone in vessels from nonpregnant and pregnant rats

Recent evidence suggests oxytocin (OT) may regulate vascular tone. OT and its receptor (OTR) have been identified in the rat heart and great vessels. Expression of OT and OTR is increased in some tissues during pregnancy. We hypothesized that the OT/OTR system may be a physiological regulator of vascular tone and mediate the decreased vascular resistance noted during pregnancy. Using a wire myograph system, we measured changes in vascular tone in response to OT in small mesenteric arteries, uterine arcuate arteries, and thoracic aorta from nonpregnant and pregnant rats. Additionally, we used reverse transcriptase-polymerase chain reaction (RT-PCR) to measure mRNA for OTR in these vascular tissues. Although OTR mRNA was identified by RT-PCR, OT did not elicit a vasodilatory effect in any of the vessels studied. High concentrations of OT (>10(-8) M) caused vasoconstriction that was eliminated by a specific vasopressin V(1a) receptor antagonist. Although it may have an indirect effect in regulation of peripheral resistance, we conclude that OT is unlikely to play a direct role in the physiological regulation of vascular tone.

Ethnic differences in asthma and associated phenotypes: collaborative study on the genetics of asthma

BACKGROUND

In the Collaborative Study on the Genetics of Asthma, 314 families with 2584 subjects were characterized for asthma and allergy.

OBJECTIVE

The purpose of this investigation was to examine clinical heterogeneity observed in asthma and allergic characteristics among 3 ethnic groups (African American, white, and Hispanic family members).

METHODS

Pulmonary function parameters and asthma associated phenotypes were compared among the ethnic groups.

RESULTS

In comparison with the other groups, African American sibling pairs had a significantly lower baseline FEV(1) percent of predicted (P =.0001) and a higher rate of skin test reactivity to cockroach allergen (P =.0001); Hispanic sibling pairs had significantly more skin reactivity overall (P =.001); and white sibling pairs had significantly lower total serum IgE (P <.05). In addition, there were significantly more relatives with asthma among the African American families than among the white and the Hispanic families (P =.001).

CONCLUSION

Although different environmental backgrounds should be considered, these clinical differences could be due to differences in genetic susceptibility among the ethnic groups, such as those suggested by our previous genome screen.

Monitoring pregnancy in babirusa (Babyrousa babyrussa) with transabdominal ultrasonography

This case report documents the application of transabdominal ultrasonography for detecting pregnancy and monitoring fetal development in an unanesthetized, unrestrained babirusa (Babyrousa babyrussa). A 4-yr-old multiparous female babirusa was trained to accept monitoring via transabdominal ultrasonography on a weekly basis postcoitus. Uterine changes associated with pregnancy were first detected at 30 days gestation. Three fetuses were first visualized on day 38, and two of the three fetuses were detectable until term. One fetus failed to develop and appeared to be resorbed between days 80 and 94 of the 161-day pregnancy. The growth of the remaining two fetuses was monitored via cranial measurements taken during the weekly scans throughout the pregnancy. By monitoring a subsequent pregnancy via ultrasound in the same female it was possible to confirm her tendency towards partial resorption, with earliest detection of uterine changes on day 32 and apparent resorption of one of three fetuses at approximately the midpoint of gestation. Two rectal scans of a different female under anesthesia at 28 and 50 days gestation showed stages of development comparable to those visualized transabdominally. However, the transabdominal scans produced better images of the reproductive tract, perhaps because of the close proximity of the pregnant uterus to the abdominal wall.

Mechanisms controlling subcellular localization of the G(1) cyclins Cln2p and Cln3p in budding yeast

Different G(1) cyclins confer functional specificity to the cyclin-dependent kinase (Cdk) Cdc28p in budding yeast. The Cln3p G(1) cyclin is localized primarily to the nucleus, while Cln2p is localized primarily to the cytoplasm. Both binding to Cdc28p and Cdc28p-dependent phosphorylation in the C-terminal region of Cln2p are independently required for efficient nuclear depletion of Cln2p, suggesting that this process may be physiologically regulated. The accumulation of hypophosphorylated Cln2 in the nucleus is an energy-dependent process, but may not involve the RAN GTPase. Phosphorylation of Cln2p is inefficient in small newborn cells obtained by elutriation, and this lowered phosphorylation correlates with reduced Cln2p nuclear depletion in newborn cells. Thus, Cln2p may have a brief period of nuclear residence early in the cell cycle. In contrast, the nuclear localization pattern of Cln3p is not influenced by Cdk activity. Cln3p localization requires a bipartite nuclear localization signal (NLS) located at the C terminus of the protein. This sequence is required for nuclear localization of Cln3p and is sufficient to confer nuclear localization to green fluorescent protein in a RAN-dependent manner. Mislocalized Cln3p, lacking the NLS, is much less active in genetic assays specific for Cln3p, but more active in assays normally specific for Cln2p, consistent with the idea that Cln3p localization explains a significant part of Clnp functional specificity.

Self-efficacy and the progression of functional limitations and self-reported disability in older adults with knee pain

OBJECTIVES

The prospective relationships between self-efficacy beliefs, in conjunction with measures of knee pain and knee strength, and subsequent decline in both physical performance and self-reported disability among older adults with knee pain were examined.

METHODS

In this prospective epidemiological trial, 480 men and women aged 65 years and older who had knee pain on most days of the week and difficulty with daily activity were followed for 30 months.

RESULTS

There was a significant interaction of baseline self-efficacy with baseline knee strength in predicting both self-reported disability and stair climb performance. Participants who had low self-efficacy and low strength at baseline had the largest 30-month decline in these outcomes.

DISCUSSION

These data underscore the important role that self-efficacy beliefs play in understanding functional decline with chronic disease and aging. Self-efficacy beliefs appear to be most important to functional decline in older adults when they are challenged by muscular weakness in the lower extremities.

Group comparisons involving missing data in clinical trials: a comparison of estimates and power (size) for some simple approaches

When using 'intent-to-treat' approaches to compare outcomes between groups in clinical trials, analysts face a decision regarding how to account for missing observations. Most model-based approaches can be summarized as a process whereby the analyst makes assumptions about the distribution of the missing data in an attempt to obtain unbiased estimates that are based on functions of the observed data. Although pointed out by Rubin as often leading to biased estimates of variances, an alternative approach that continues to appear in the applied literature is to use fixed-value imputation of means for missing observations. The purpose of this paper is to provide illustrations of how several fixed-value mean imputation schemes can be formulated in terms of general linear models that characterize the means of distributions of missing observations in terms of the means of the distributions of observed data. We show that several fixed-value imputation strategies will result in estimated intervention effects that correspond to maximum likelihood estimates obtained under analogous assumptions. If the missing data process has been correctly characterized, hypothesis tests based on variances estimated using maximum likelihood techniques asymptotically have the correct size. In contrast, hypothesis tests performed using the uncorrected variance, obtained by applying standard complete data formula to singly imputed data, can provide either conservative or anticonservative results. Surprisingly, under several non-ignorable non-response scenarios, maximum likelihood based analyses can yield equivalent hypothesis tests to those obtained when analysing only the observed data.

Modifiers of change in physical functioning in older adults with knee pain: the Observational Arthritis Study in Seniors (OASIS)

OBJECTIVE

To ascertain predictors of decline in physical functioning among older adults reporting knee pain.

METHODS

The Observational Arthritis Study in Seniors was a longitudinal study of 480 adults over 65 years of age. Measurements of strength, sociodemographic characteristics, disease burden (including radiographic knee osteoarthritis [OA]), self-reported disability, and functional limitations were obtained on participants at baseline and at 15 and 30 months.

RESULTS

Radiographic evidence of OA at baseline was moderately associated with an increased decline in both transfer (P = 0.06) and ambulatory-based performance tasks (P = 0.04) but not in self-reported disability. This effect disappeared after accounting for baseline levels of knee pain intensity and knee strength.

CONCLUSION

Knee pain intensity and knee strength may mediate the relationship between radiographic evidence of knee OA and change in performance. Although it is not clear whether joint disease precedes or follows a decline in muscular strength, these results may help to identify subpopulations of older persons with knee OA who may benefit from interventions aimed at slowing the progression of disability related to transfer and ambulatory-based tasks.

Hispanic versus white, non-Hispanic physician medical practices in Colorado

The purpose of the study was to extend the scope of earlier research on minority physicians attending to the needs of the poor and their own ethnicity by contrasting practice characteristics of Hispanic doctors in Colorado with those of their white, non-Hispanic counterparts. It was found that Hispanic physicians spent more hours per week in direct patient care, were more likely to have a primary care specialty, and were less often specialty board certified than white, non-Hispanic doctors. Hispanic generalists established practices in areas in which the percentages of the population that were (1) below poverty level, (2) Hispanic, (3) Hispanic and below poverty level, and (4) white, non-Hispanic, and below poverty level were greater than in areas in which white, non-Hispanic primary care physicians practiced. These findings argue for special provision to admit ethnic minorities to undergraduate and graduate medical education programs.

Antihypertensive effect of alpha- and beta-adrenergic blockade in obese and lean hypertensive subjects

The purpose of this study was to determine the contribution of the adrenergic system in mediating hypertension in obese and lean patients. Thirteen obese, hypertensive patients with a body mass index (BMI) > or =28 kg/m2 (obese) and nine lean patients with a BMI < or =25 kg/m2 (lean) were recruited. After a 1-week washout period, participants underwent daytime ambulatory blood pressure monitoring (ABPM). Participants were then treated with the alpha-adrenergic antagonist doxazosin, titrating to 4 mg QHS in 1 week. In the next week, the beta-adrenergic antagonist atenolol was added at an initial dose of 25 mg/day and titrated to 50 mg/day within 1 week. One month after the addition of atenolol, all patients underwent a second ABPM session. There were no differences between the obese and lean subjects in baseline systolic (SBP), diastolic (DBP), or mean arterial pressures (MAP) measured by office recording or ABPM. However, obese subjects had higher heart rates than lean subjects (87.5+/-2.4 v 76.8+/-4.9 beats/min). After 1 month of treatment with the adrenergic blockers, obese patients had a significantly lower SBP (130.0+/-2.5 v 138.9+/-2.1 mm Hg, P = .02) and MAP (99.6+/-2.3 v 107.0+/-1.5 mm Hg, P = .02) than lean patients. Obese patients also tended to have a lower DBP than lean patients (84.3+/-2.5 v 90.9+/-1.6 mm Hg, P = .057), but there was no significant difference in heart rate after 1 month of adrenergic blockade. These results indicate that blood pressure is more sensitive to adrenergic blockade in obese than in lean hypertensive patients and suggest that increased sympathetic activity may be an important factor in the maintenance of hypertension in obesity.

The health risk of hypertension in south Texas: a demographic profile

This article provides a demographic profile of the hypertensive adult in South Texas. Hypertension, a silent disease because of its lack of overt signs and symptoms, poses a major public health problem. Few prevalence studies have been completed reflecting Mexican-American populations. South Texas hypertension trends are comparable to national trends. However, the awareness of hypertension in South Texas is lower than that of the national population. The density of risk factors may be responsible for the patterns of South Texas hypertension.

Strength, balance, and the modifying effects of obesity and knee pain: results from the Observational Arthritis Study in Seniors (oasis)

OBJECTIVE

To examine the relationship between muscular strength and dynamic balance in a sample of older adults with knee pain and to determine the role that obesity and severity of knee pain play in the ability to maintain balance.

DESIGN

Cross-sectional study designed to examine the association between strength and balance in a cohort of older adults with chronic knee pain.

SETTING

A university health and exercise science center.

PARTICIPANTS

A cohort of 480 adults age 65 and older with knee pain.

MEASUREMENTS

Force platform dynamic balance measure of the center of pressure excursion during a forward and subsequent backward lean. Isokinetic strength measures of concentric and eccentric knee flexion and extension and concentric ankle plantar flexion and dorsiflexion. Body mass index (BMI) and a knee pain scale were used to measure obesity and knee pain, respectively.

RESULTS

A regression model was developed to investigate the relationship between dynamic balance and muscular strength while controlling for gender, BMI, radiographic severity, knee pain, and foot length. Knee strength alone explained 18.4% of the variability in dynamic balance. The addition of knee pain, BMI, radiographic severity, gender, and foot length explained an additional 6.7%. When the knee-ankle interaction, ankle strength, and knee strength--pain interaction variables were added to the regression model, 28.9% of the variability in dynamic balance was explained.

CONCLUSIONS

Strength appears to play a significant role in maintaining balance in an older, osteoarthritic population. We found that mean knee strength accounted for approximately 19% of the variability in dynamic balance. Hence, greater knee strength was associated with better dynamic balance. The best dynamic balance performances occurred in participants that had a combination of strong knees and strong ankles. However, knee osteoarthritic patients with weak knee strength could still maintain high levels of dynamic balance by having strong ankle strength. Moreover, we have shown that obesity is associated with attenuated dynamic balance performance and that poorer balance is associated with higher pain scores in the presence of weaker knees. For stronger knees, however, pain does not appear to be related to balance.

Cyclin specificity: how many wheels do you need on a unicycle?

Cyclin-dependent kinase (CDK) activity is essential for eukaryotic cell cycle events. Multiple cyclins activate CDKs in all eukaryotes, but it is unclear whether multiple cyclins are really required for cell cycle progression. It has been argued that cyclins may predominantly act as simple enzymatic activators of CDKs; in opposition to this idea, it has been argued that cyclins might target the activated CDK to particular substrates or inhibitors. Such targeting might occur through a combination of factors, including temporal expression, protein associations, and subcellular localization.

End-user exposures to synthetic vitreous fibers: II. Fabrication and installation fabrication of commercial products

This article summarizes the results of exposure monitoring conducted during the installation and fabrication of commercial synthetic vitreous fiber (SVF) products. Included in this investigation were fiberglass duct insulation and construction applications (duct board, duct liner, and duct wrap), pipe and vessel insulation, batt insulation for prefabricated homes, and general fiberglass products. Commercial mineral wool products sampled as a part of this investigation included ceiling tiles, building safing, and loose insulation for prefabricated homes. A total of 520 valid air samples were collected as a part of this investigation and were analyzed using gravimetric, phase contrast microscopy (PCM), or scanning electron microscopy (SEM). Airborne fiber-size distributions were also determined for a subset of samples collected for SEM analysis. As a result of the task-based sampling strategy used in this study, sample times reflect exposures over the time the person was actually engaged in SVF-related work activities, and exposure results are therefore presented as task-length averages (TLAs). Thirty-five total dust samples were collected as a part of this investigation, resulting in 14 TLAs ranging from 0.3 to 7.6 mg/m3. A total of 125 PCM-based TLAs were collected, with the mean TLA time for all product and occupation categories ranging from 277 to 443 minutes. The mean PCM-based TLAs for all product/occupations were below 1.0 f/cm3, ranging from 0.04 to 0.68 f/cm3. A total of 116 SEM TLAs were determined. Average SEM-based TLA concentrations were slightly lower than the PCM-based estimates and ranged from <0.01 to 0.16 f/cm3. The geometric mean fiber diameters for commercial products and occupations sampled as a part of the investigation ranged from 0.8 microm to 1.9 microm. Geometric mean fiber length varied by a factor of approximately three, ranging from 9.5 microm to 29.5 microm.

Multi-method assessment of access to primary medical care in rural Colorado

The objectives of this study include conducting an analysis of access to primary medical care in rural Colorado through simultaneous consideration of primary care physician-to-population and distance-to-nearest provider indices. Analyses examined the potential development and implications of excessively large, perhaps unmanageable patient caseloads that might result from every rural Coloradoan's exclusive use of the nearest generalist physician as a regular source of care. Using American Medical Association Physician Masterfile data for 1995 and coordinates for latitude and longitude from U.S. Census files (Census of Population and Housing, 1990), the authors calculated distance to the nearest primary care physician for residents of each of the 1,317 block groups in Colorado's 52 rural counties. Caseloads for each generalist physician were computed assuming the population used the nearest provider for care. Straight-line mileage to primary medical care was modest for rural Coloradoans--a median distance of 2.5 miles. Almost two-thirds (65 percent) of the population resided within 5 miles, and virtually all residents (99 percent) were within 30 miles of a generalist physician. However, had everyone traveled the shortest possible distance to care, demand for service from many of the 343 primary care doctors in rural regions of the state would have been overwhelming. The results of simultaneous application of distance-to-care and provider-to-population techniques unrestricted by geographic boundaries depict access to primary medical care and corresponding consumer difficulty more fully than in previous studies. Further combination of methods of needs assessment such as those used in this analysis may better inform the future efforts of organizations mandated to address health care underservice in rural areas.

Perceived importance and satisfaction with physical function in patients with knee osteoarthritis

This investigation examined the determinants of satisfaction with physical function for participants in an Observational Arthritis Study in Seniors (OASIS). The sample consisted of 480 men (51%) and women (49%) over the age of 65 years who had difficulty performing activities of daily living due to knee pain. As part of baseline testing for OASIS, participants completed a measure that assessed satisfaction with function for six physical activities. After controlling for relevant covariates, scores on the satisfaction index were regressed on seven conceptually relevant predictor variables. The results revealed that satisfaction with physical function is a distinct construct from level of function, irrespective of whether the latter variable is measured objectively or subjectively. When entered into a hierarchical regression model, 6-minute walk test data accounted for 11% of the variance in satisfaction scores, whereas perceived difficulty accounted for an additional 22%. Moreover, a significant interaction term between importance and perceived difficulty revealed that patients who rated the activities as important and who had high levels of perceived difficulty had the lowest satisfaction scores. Discussion focuses on the determinants of satisfaction with physical function with emphasis on the interaction between perceived difficulty and importance.