Tissue Characterization Using Synchrotron Radiation at 0.7 THz to 10.0 THz with Extended ATR Apparatus Techniques.

The attenuated total reflection (ATR) apparatus, with an added partial reflection/partial transmission mode, was used to demonstrate a novel way of characterizing water-based substances at 0.7 to 10.0 THz at the Australian Synchrotron THz-far infrared beamline. The technique utilized a diamond-crystal-equipped ATR to track temperature-dependent changes in reflectance. A "crossover flare" feature in the spectral scan was noted, which appeared to be a characteristic of water and water-dominated compounds. A "quiet zone" feature was also seen, where no temperature-dependent variation in reflectance exists. The variation in these spectral features can be used as a signature for the presence of bound and bulk water. The method can also potentially identify the presence of fats and oils in a biological specimen. The technique requires minimal sample preparation and is non-destructive. The presented method has the promise to provide a novel, real-time, low-preparation, analytical method for investigating biological material, which offers avenues for rapid medical diagnosis and industrial analysis.

Cannula-based drug delivery to the guinea pig round window causes a lasting hearing loss that may be temporarily mitigated by BDNF.

Sustained local delivery of drugs to the inner ear may be required for future regenerative and protective strategies. The round window is surgically accessible and a promising delivery route. To be viable, a delivery system should not cause hearing loss. This study determined the effect on hearing of placing a drug-delivery microcatheter on to the round window, and delivering either artificial perilymph (AP) or brain-derived neurotrophic factor (BDNF) via this catheter with a mini-osmotic pump. Auditory brainstem responses (ABRs) were monitored for 4 months after surgery, while the AP or BDNF was administered for the first month. The presence of the microcatheter - whether dry or when delivering AP or BDNF for 4 weeks - was associated with an increase in ABR thresholds of up to 15 dB, 16 weeks after implantation. This threshold shift was, in part, delayed by the delivery of BDNF. We conclude that the chronic presence of a microcatheter in the round window niche causes hearing loss, and that this is exacerbated by delivery of AP, and ameliorated temporarily by delivery of BDNF.

Electrophysiological Evidence of the Basilar-Membrane Travelling Wave and Frequency Place Coding of Sound in Cochlear Implant Recipients.

AIM: To obtain direct evidence for the cochlear travelling wave in humans by performing electrocochleography from within the cochlea in subjects implanted with an auditory prosthesis. BACKGROUND: Sound induces a travelling wave that propagates along the basilar membrane, exhibiting cochleotopic tuning with a frequency-dependent phase delay. To date, evoked potentials and psychophysical experiments have supported the presence of the travelling wave in humans, but direct measurements have not been made. METHODS: Electrical potentials in response to rarefaction and condensation acoustic tone bursts were recorded from multiple sites along the human cochlea, directly from a cochlear implant electrode during, and immediately after, its insertion. These recordings were made from individuals with residual hearing. RESULTS: Electrocochleography was recorded from 11 intracochlear electrodes in 7 ears from 6 subjects, with detectable responses on all electrodes in 5 ears. Cochleotopic tuning and frequency-dependent phase delay of the cochlear microphonic were demonstrated. The response latencies were slightly shorter than those anticipated which we attribute to the subjects' hearing loss. CONCLUSIONS: Direct evidence for the travelling wave was observed. Electrocochleography from cochlear implant electrodes provides site-specific information on hair cell and neural function of the cochlea with potential diagnostic value.

Correlates of smoking among youth: the role of parents, friends, attitudes/beliefs, and demographics.

BACKGROUND: Family engagement has been shown to play a crucial role in youth cigarette use prevention and uptake. We examine cross-sectional and longitudinal data to determine whether changes in parental monitoring factors influence changes in smoking susceptibility. METHODS: Two cross-sectional surveys of Florida youth (12-17 years) were conducted in 2009, with a follow-up survey in 2010. Multivariable analyses examined demographics, parent characteristics, family engagement, and parental monitoring on youth susceptibility to smoke. RESULTS: Cross-sectional data show eating together 6+ times/week and doing something for fun 5+ times/week were related to an increased likelihood of Very Low and decreased likelihood of High susceptibility, respectively. Parental monitoring factors and parents tell on a friend who smokes was significantly related to having Very Low susceptibility in both surveys. Mother's education, parent smokes, family engagement factors, and parental monitoring were significant in both survey rounds. Longitudinal analyses showed change in eating together did not significantly affect the odds of change in smoking susceptibility; however, change in the frequency of doing things for fun with a parent showed decreased odds of susceptibility (OR = .63 [.49-.82]), opposite of the hypothesized direction. Lastly, as youth aged, they were more likely to experience a greater odds of decreased susceptibility (OR14-15y = 1.47 [1.08-1.99] and OR≥16y = 1.40 [1.05-1.84], respectively) and less likely to experience an increased odds of susceptibility (OR14-15y = .65 [.49-.86] and OR≥16y = .72 [.56-.93], respectively). CONCLUSIONS: We found mixed results for family engagement and parental monitoring on changes in youth smoking susceptibility. Cross-sectional data showed general associations in the expected direction; however, longitudinal analyses showed family engagement variables had significance, but in the opposite hypothesized direction.

Identifying misclassification in youth self-reported smoking status: testing different consent processes of biological sample collection to capture misclassification.

INTRODUCTION: In Florida, since 1998, identical survey items have been used to measure youth smoking status for the CDC sponsored state school-based survey and the tobacco control program evaluation telephone survey. The two surveys should parallel one another to track tobacco use. Tobacco items collected in the two surveys closely paralleled one another until recently. Since 2008, data show dramatically divergent youth smoking estimates (e.g., relative differences as high as 50%), which cannot be explained by differences in survey and sampling design. As a first step in detecting misclassification of smoking status, we examined the feasibility of asking youth to self-report their smoking behavior and collect a biological sample, with the expectation that some youth will misreport their smoking status. METHODS: Using a cross-sectional population level telephone survey, youth were randomly assigned to one of three groups to test mode effects of collecting biological data with self-reported survey data (n = 303). RESULTS: It showed two groups of youth (those who are not asked for a biological and those asked for a biological with an indirect explanation of its use) had similar response rates and self-reported smoking status, while the third group (biological request with a direct explanation of its use) had a substantially lower response rate and self-reported smoking status. CONCLUSIONS: The data show youth who are given an indirect explanation of how biological data are to be used were as likely to self-report their smoking status as youth who were not asked to provide a biological sample.

Young adult former ever smokers: the role of type of smoker, quit attempts, quit aids, attitudes/beliefs, and demographics.

OBJECTIVE: Young adults who smoke are often nondaily users who either quit or transition into dependent smokers. Further, this age group often has been considered an extension of the adult population. This study aims to examine young adult former ever smokers to understand factors associated with their stopping smoking. METHOD: Telephone interviews were conducted in 2010 with 4401 young adults in Florida. We examined the association between former ever smokers and sociodemographics, smoking behavior, quit attempts, quit aids, and attitudes/beliefs about smoking. RESULTS: Thirty-seven percent of young adults were former smokers, 20% were current smokers, and 43% were never smokers. Former smokers were more likely to be female, situational smokers (compared to occasional or established), more likely to have stopped smoking without acknowledging making a quit attempt, less likely to have used a quit aid, and less likely to display pro-tobacco attitudes/beliefs. CONCLUSION: Young adult former and current smokers have unique patterns of smoking and stopping smoking. Young adults may require novel intervention techniques to promote prevention and cessation based on these unique smoking patterns. Future research is needed to understand motivations to quit smoking among young adults.

Correlates of smoking among young adults: the role of lifestyle, attitudes/beliefs, demographics, and exposure to anti-tobacco media messaging.

BACKGROUND: Young adults (18-24 years) have the highest smoking rate of any age group. Unlike youth/adult populations where there is one primary message targeting behavior, anti-tobacco campaigns targeting young adults should contain messages of prevention and cessation. The objective was to identify factors influencing young adult cigarette use, employing the Centers for Disease Control and Prevention logic model, with an emphasis on the role of lifestyle, tobacco use tolerance, and attitudes/beliefs. METHODS: Cross-sectional data were collected from 4401 young adults using telephone interviews in 2010 as part of the evaluation for the Tobacco Free Florida Campaign. Multivariate logistic regression was used to examine the relationship between current smoking status and lifestyles, tolerance of tobacco use, and attitude/belief variables. RESULTS: The young adult cigarette prevalence rate is 20.3%, with males more likely to be smokers (25.1%) than females (15.6%) and non-Hispanic Whites more likely to be smokers than other racial/ethnic groups (23.8%). Significant associations were found between lifestyle variables (frequent bar/club, drinks per month, and number of friends who smoke), tolerance of tobacco use (allow smoke in house/car and moderate tobacco use), and four attitude/belief indices and current smoking behavior. CONCLUSIONS: Results suggest lifestyles and attitudes/beliefs should be key behavioral targets of prevention programs aimed at young adults. Data strongly suggest that as young adults reject negative labels attached to smokers, they are more likely to smoke. Prevention (and cessation) programs may need to reduce barriers that result in segregating nonsmokers/smokers so smokers can have an increased chance of adopting attitudes/beliefs of nonsmokers.

Changes in youth cigarette use following the dismantling of an antitobacco media campaign in Florida.

We examined the association of the termination of a successful youth-targeted antitobacco media campaign ("truth") and changes in smoking rates among youths aged 12-17 years in Florida. Six telephone-based surveys were completed during the active media campaign (1998-2001), and 2 postcampaign surveys were completed in 2004 and 2006 (each n approximately 1,800). Prevalence of current smoking among youth observed during the campaign continued to decrease in the first postcampaign survey; however, by the second follow-up survey, youth smoking rates had increased significantly for youth aged 16 years or older. Our findings support the need for consistent antitobacco messaging to reduce the prevalence of youth smoking.

Round window delivery of dexamethasone ameliorates local and remote hearing loss produced by cochlear implantation into the second turn of the guinea pig cochlea.

Application of dexamethasone to the round window has been shown to ameliorate high frequency hearing loss resulting from the trauma of cochlear implantation in experimental animals, but elucidation of the factors influencing protection of the high frequencies has been confounded by the local trauma from electrode array insertion. In this experiment, a second turn cochleostomy and implantation was performed on guinea pigs, to examine protection in the basal turn without the confounding effect of local trauma, as well as to test the efficacy of hearing protection in the second cochlear turn. The implantation resulted in an increase in hearing thresholds across all frequencies examined (2-32 kHz). Local delivery of dexamethasone to the round window prior to implantation protected hearing across frequencies from 2 to 32 kHz. Auditory thresholds improved over the first week after surgery, and then remained stable for the month of the experiment. The protection of hearing in the basal turn increased with longer periods of drug application prior to implantation. The level of hearing protection in the second turn was similar irrespective of the time that the drug was applied, but was greater when a higher steroid concentration was used. It was concluded that steroids protect hearing in the basal turn of the cochlea even when there was no local trauma. The level of hearing protection in the second turn exceeded that expected from models of steroid diffusion through the cochlea, suggesting that inner ear surgery alters the distribution of dexamethasone within the cochlea.

Targeted therapy of the inner ear.

BACKGROUND: There is experimental evidence that targeted delivery of steroids to the inner ear can protect hearing during cochlear implant surgery. The best protection appears to be achieved through pre-treatment of the cochlea, but the time period required for treatment is long compared with the duration of surgery, and needs further optimization. The stability of hearing thresholds is determined over a 3-month period after hearing preservation cochlear implantation. METHODS: Adult guinea pigs were implanted with a miniature cochlear implant electrode, and pure tone auditory brainstem response (ABR) thresholds were estimated in response to pure tones of 2-32 kHz immediately after surgery and at 1 week, 1 month and 3 months. Spiral ganglion cell (SGC) densities were estimated from mid-modular histological sections of the cochlea. Thirty minutes prior to implantation, a polymeric sponge (Seprapack, Genzyme) was loaded with either a 2% solution of dexamethasone phosphate or normal saline (control) and placed onto the round window. RESULTS: Implantation was associated with an immediate elevation in thresholds across frequencies, with a full recovery below 2 kHz over the next week and a partial recovery of thresholds at higher frequencies. These thresholds remained unchanged for the next 3 months. There was an immediate and sustained reduction in the elevation of thresholds at 32 kHz in dexamethasone-treated animals. SGC densities were greater in steroid-treated animals than controls in the basal turn of the cochlea (at the region of implantation) 3 months after implantation. CONCLUSION: It is concluded that ABR thresholds remain stable for 3 months after cochlear implantation in the guinea pig, and that local application of steroids to the inner ear prior to implantation is an effective method of preserving SGC populations when there is residual hearing at the time of implantation.

Factors influencing the efficacy of round window dexamethasone protection of residual hearing post-cochlear implant surgery.

AIM: To protect hearing in an experimental model of cochlear implantation by the application of dexamethasone to the round window prior to surgery. The present study examined the dosage and timing relationships required to optimise the hearing protection. METHODS: Dexamethasone or saline (control) was absorbed into a pledget of the carboxymethylcellulose and hyaluronic acid and applied to the round window of the guinea pig prior to cochlear implantation. The treatment groups were 2% w/v dexamethasone for 30, 60 and 120min; 20% dexamethasone applied for 30min. Auditory sensitivity was determined pre-operatively, and at 1 week after surgery, with pure-tone auditory brainstem response audiometry (2-32kHz). Cochlear implantation was performed via a cochleostomy drilled into the basal turn of the cochlea, into which a miniature cochlear implant dummy electrode was inserted using soft-surgery techniques. RESULTS: ABR thresholds were elevated after cochlear implantation, maximally at 32kHz and to a lesser extent at lower frequencies. Thresholds were less elevated after dexamethasone treatment, and the hearing protection improved when 2% dexamethasone was applied to the round window for longer periods of time prior to implantation. The time that dexamethasone need be applied to achieve hearing protection could be reduced by increasing the concentration of steroid, with a 20% application for 30min achieving similar levels of protection to a 60min application of 2% dexamethasone. CONCLUSIONS: Hearing protection is improved by increasing the time that dexamethasone is applied to the round window prior to cochlear implantation, and the waiting time can be reduced by increasing the steroid concentration. These results suggest that the diffusion dexamethasone through the cochlea is the prime determinant of the extent of hearing protection.

Using classification trees to profile adolescent smoking behaviors.

The purpose of this study was to explore the interactive nature of various predictor variables in profiling adolescent smoking behaviors characterized by intention to smoke, current, situational, and established smoking using classification trees. The data (n = 3610) were obtained from cross-sectional telephone surveys of the Florida Anti-Tobacco Media Evaluation Program. Three classification trees were constructed, namely, intention versus no intention to smoke among non-smokers, current smokers versus non-smokers, and established versus situational smokers. The tree model for the intention model revealed that social and health risks are important in the context of peer smoking. Certain variables such as peer smoking and alcohol consumption retained their relative importance across the tree classifiers demonstrating that smoking intention may be predictable using some of the same variables as in current or more dependent smoking.

The outcome consequences of defunding the Minnesota youth tobacco-use prevention program.

OBJECTIVE: To assess the immediate and intermediate outcome consequences of defunding a successful tobacco use prevention program. METHODS: A four-survey repeated cross-sectional design is employed. Two surveys were completed while the program was fully operational, one after program dismantling was initiated and another about 6 months after the campaign was completely dismantled. Survey to survey trends for five immediate and six intermediate outcomes are analyzed. Changes in measures are tested employing chi-square estimated using SAS 8. RESULTS: Each immediate outcome measure declined significantly from the third to the fourth survey except one, and this measure declined from the second to the third survey when it was eliminated. All intermediate outcomes showed significant change from the third or second to the fourth survey. These include two measures of openness to smoking, three attitude/belief scales and one measure of intention to smoke. CONCLUSIONS: Defunding a successful tobacco-use prevention campaign results in rapid erosion of program messages, parallel increases in susceptibility, a rapid and sharp re-emergence of pro-tobacco attitudes/beliefs and a marked rise in intentions to smoke.

Assessing the reliability and validity of anti-tobacco attitudes/beliefs in the context of a campaign strategy.

OBJECTIVES: To identify multi-item attitude/belief scales associated with the theoretical foundations of an anti-tobacco counter-marketing campaign and assess their reliability and validity. METHODS: The data analyzed are from two state-wide, random, cross-sectional telephone surveys [n(S1)=1,079, n(S2)=1,150]. Items forming attitude/belief scales are identified using factor analysis. Reliability is assessed with Chronbach's alpha. Relationships among scales are explored using Pearson correlation. Validity is assessed by testing associations derived from the Centers for Disease Control and Prevention's (CDC) logic model for tobacco control program development and evaluation linking media exposure to attitudes/beliefs, and attitudes/beliefs to smoking-related behaviors. Adjusted odds ratios are employed for these analyses. RESULTS: Three factors emerged: traditional attitudes/beliefs about tobacco and tobacco use, tobacco industry manipulation and anti-tobacco empowerment. Reliability coefficients are in the range of 0.70 and vary little between age groups. The factors are correlated with one-another as hypothesized. Associations between media exposure and the attitude/belief scales and between these scales and behaviors are consistent with the CDC logic model. CONCLUSIONS: Using reliable, valid multi-item scales is theoretically and methodologically more sound than employing single-item measures of attitudes/beliefs. Methodological, theoretical and practical implications are discussed.

Evidence of the dose effects of an antitobacco counteradvertising campaign.

OBJECTIVE: The objectives were to assess the cumulative effects of exposure to multiple antitobacco advertisements shown over a 22-month period on smoking uptake, and determine if there is evidence of a dose effect and how this effect operates through response to the campaign's major message theme and antitobacco attitudes. METHODS: A follow-up telephone survey of persons ages 12-20 years was conducted after 22 months of the Florida "truth" antitobacco media campaign. Logistic regression analyses were used to estimate adjusted odds ratios for the likelihood that time-one nonsmokers would remain nonsmokers at time two by levels of confirmed advertisement awareness, self-reported influence of the campaign's message theme, and anti-tobacco industry manipulation attitudes. Separate cohorts are analyzed and controls include gender and time-one susceptibility. RESULTS: The likelihood of nonsmokers remaining nonsmokers increases as the number of ads confirmed, the self-reported influence of the campaign's major message theme, and the level of antitobacco attitudes increases. The pattern to these relationships holds within cohorts of young and older youth and for a cohort that has aged into the early young adult years. Considering all variables simultaneously suggests that ad confirmation operates through its effects on the influence of the message theme and antitobacco industry manipulation attitudes. CONCLUSIONS: There is evidence of a dose effect; however, considering only ad confirmation underestimates this. Antitobacco campaigns that target youth can have effects at least through the early young adult ages. The uniqueness of the Florida campaign may limit the generalization of reported results.