Problematic internet usage in US college students: a pilot study.

BACKGROUND: Internet addiction among US college students remains a concern, but robust estimates of its prevalence are lacking. METHODS: We conducted a pilot survey of 307 college students at two US universities. Participants completed the Internet Addiction Test (IAT) as well as the Patient Health Questionnaire. Both are validated measures of problematic Internet usage and depression, respectively. We assessed the association between problematic Internet usage and moderate to severe depression using a modified Poisson regression approach. In addition, we examined the associations between individual items in the IAT and depression. RESULTS: A total of 224 eligible respondents completed the survey (73% response rate). Overall, 4% of students scored in the occasionally problematic or addicted range on the IAT, and 12% had moderate to severe depression. Endorsement of individual problematic usage items ranged from 1% to 70%. In the regression analysis, depressive symptoms were significantly associated with several individual items. Relative risk could not be estimated for three of the twenty items because of small cell sizes. Of the remaining 17 items, depressive symptoms were significantly associated with 13 of them, and three others had P values less than 0.10. There was also a significant association between problematic Internet usage overall and moderate to severe depression (relative risk 24.07, 95% confidence interval 3.95 to 146.69; P = 0.001). CONCLUSION: The prevalence of problematic Internet usage among US college students is a cause for concern, and potentially requires intervention and treatment amongst the most vulnerable groups. The prevalence reported in this study is lower than that which has been reported in other studies, however the at-risk population is very high and preventative measures are also recommended.

Walking stride rate patterns in children and youth.

PURPOSE: To describe walking activity patterns in youth who are typically developing (TD) using a novel analysis of stride data and compare to youth with cerebral palsy (CP) and arthrogryposis (AR). METHOD: Stride rate curves were developed from 5 days of StepWatch data for 428 youth ages 2 to 16 years who were TD. RESULTS: Patterns of stride rates changed with age in the TD group (P = .03 to < .001). Inactivity varied with age (P < .001); peak stride rate decreased with age (P < .001). Curves were stable over a 2-week time frame (P = .38 to .95). Youth with CP and AR have lower stride rate patterns (P = .04 to .001). CONCLUSION: This is the first documentation of pediatric stride-rate patterns within the context of daily life. Including peak stride rates and levels of walking activity, this single visual format has potential clinical and research applications.

Optimization of optical spectral throughput of acousto-optic modulators for high-speed optical coherence tomography.

We describe a generic method to optimize the optical spectral throughput of a pair of acousto-optic modulators (AOM) which can be used for introducing a frequency shift in ultrahigh-resolution heterodyne optical coherence tomography. Systematic and quantitative analysis of a pair of AOMs indicates that a configuration with a spectral bandwidth of more than 200 nm at a center wavelength of 825 nm (tunable) can be achieved. Using a pair of AOMs in conjunction with a broadband low coherence light source, real-time imaging of biological tissues with an axial resolution ~3 microm (in air) has been experimentally demonstrated with a high-speed OCT system.

Parental cultural attitudes and beliefs regarding young children and television.

IMPORTANCE: Research has shown that preschool-aged children spend considerable time with media, and risks and benefits for cognitive and behavioral outcomes exist depending on what is watched and how it is watched. OBJECTIVE: To examine the associations among child race/ethnicity, parental beliefs/attitudes about television (TV) and child development, and TV viewing habits of young children, and to assess reasons for existing racial/ethnic disparities in children's media use. DESIGN, SETTING, AND PARTICIPANTS: Parents completed demographic questionnaires, reported on attitudes regarding media's risks and benefits to their children, and completed 1-week media diaries where they recorded all of the programs their children watched. Enrollment was from March 13, 2009, to April 12, 2010. The study was conducted at 2 metropolitan Seattle pediatric clinics and an academic practice network, each serving a diverse population of patients, and involved a community-based sample of 596 parents of children aged 3 to 5 years. MAIN OUTCOMES AND MEASURES: Parental beliefs/attitudes regarding screen time and TV viewing habits of young children. RESULTS: Overall, children watched an average (SD) of 462.0 (315.5) minutes of TV per week. African American children watched more TV per week than non-Hispanic white children (mean [SD], 638.0 [450.9] vs 431.0 [282.6] minutes; P < .01); however, these differences were no longer statistically significant after controlling for attitudes and demographic covariates (eg, family socioeconomic status). It is important to note that socioeconomic status confounded the results for race/ethnicity, and the association between race/ethnicity and media time across the sample was no longer statistically significant after adjusting for family socioeconomic status. However, significant differences were found between parents of ethnically/racially diverse children and parents of non-Hispanic white children regarding the perceived positive effects of TV viewing, even when parental education and family income were taken into account. CONCLUSIONS AND RELEVANCE: Differences in parental beliefs/attitudes regarding the effects of media on early childhood development may help explain growing racial/ethnic disparities in child media viewing/habits, but more research is needed to understand the cultural nuances of the observed differences.

The relationship between parent attitudes about childhood vaccines survey scores and future child immunization status: a validation study.

IMPORTANCE: Acceptance of childhood vaccinations is waning, amplifying interest in developing and testing interventions that address parental barriers to immunization acceptance. OBJECTIVE: To determine the predictive validity and test-retest reliability of the Parent Attitudes About Childhood Vaccines survey (PACV), a recently developed measure of vaccine hesitancy. DESIGN, SETTING, AND PARTICIPANTS: Prospective cohort of English-speaking parents of children aged 2 months and born from July 10 through December 10, 2010, who belonged to an integrated health care delivery system based in Seattle and who returned a completed baseline PACV. Parents who completed a follow-up survey 8 weeks later were included in the reliability analysis. Parents who remained continuous members in the delivery system until their child was 19 months old were included in the validity analysis. EXPOSURE: The PACV, scored on a scale of 0 to 100 (100 indicates high vaccine hesitancy). MAIN OUTCOMES AND MEASURES: Child's immunization status as measured by the percentage of days underimmunized from birth to 19 months of age. RESULTS: Four hundred thirty-seven parents completed the baseline PACV (response rate, 50.5%), and 220 (66.5%) completed the follow-up survey. Of the 437 parents who completed a baseline survey, 310 (70.9%) maintained continuous enrollment. Compared with parents who scored less than 50, parents who scored 50 to 69 on the survey had children who were underimmunized for 8.3% (95% CI, 3.6%-12.8%) more days from birth to 19 months of age; those who scored 70 to 100, 46.8% (40.3%-53.3%) more days. Baseline and 8-week follow-up PACV scores were highly concordant (ρ = 0.844). CONCLUSIONS AND RELEVANCE: Scores on the PACV predict childhood immunization status and have high reliability. Our results should be validated in different geographic and demographic samples of parents.

Current smoking as a predictor of chronic musculoskeletal pain in young adult twins.

UNLABELLED: Chronic pain is common during adolescence and young adulthood and is associated with poor quality of life, depression, and functional disability. Recognizing that chronic pain has significant consequences, it is important to identify modifiable health behaviors that may place young adults at risk for chronic pain. This study examines associations between chronic musculoskeletal pain and smoking in young adult twins (n = 1,588, ages 18-30) participating in a statewide twin registry. Twins completed questionnaires assessing smoking, mood (anxiety, depressive symptoms, and stress), and chronic musculoskeletal pain. Analyses examined associations between chronic pain and smoking, particularly the role of genetics/shared familial factors and psychological symptoms. As predicted, results revealed a near-2-fold increased risk for chronic musculoskeletal pain in twins who currently smoked compared to nonsmokers, even when accounting for psychological factors. Results of within-pair analyses were only minimally attenuated, suggesting that associations between smoking and chronic musculoskeletal pain are better accounted for by nonshared factors than by shared familial factors/genetic effects. Future twin research is needed to identify what nonshared factors (eg, attitudes, direct effects of smoking on pain) contribute to these associations to further understand comorbidity. Longitudinal studies and recruitment of participants prior to smoking initiation and chronic pain onset will better identify causal associations. PERSPECTIVE: This article describes associations between musculoskeletal pain and smoking in young adult twins, taking into account psychological symptoms. Findings highlight the importance of nonshared factors in associations between pain and smoking and the need to explore the roles of lifestyle, individual attitudes, and direct effects of smoking on pain.

What clinical differences distinguish depressed teens with and without comorbid externalizing problems?

OBJECTIVE: This study examined differences in co-occurring symptoms, psychosocial correlates, health care utilization and functional impairment in youth who screened positive for depression, stratified by whether or not they also self-reported externalizing problems. METHODS: The AdoleSCent Health Study examined a random sample of youth ages 13-17 enrolled in a health care system. A total of 2291 youth (60.7% of the eligible sample) completed a brief depression screen: the two-item Patient Health Questionnaire. The current analyses focus on a subset of youth (n=113) who had a follow-up interview and screened positive for possible depression on the Patient Health Questionnaire 9 using a cutoff score of 11 or higher [1]. Youth were categorized as having externalizing behavior if their score was ≥ 7 on the Pediatric Symptom Checklist (PSC) externalizing scale [2,3]. χ(2) tests and Wilcoxon rank sum tests were used to compare groups. RESULTS: Differences between groups included that youth with depression and externalizing symptoms had a higher rate of obesity and had higher self-reported functional impairment than youth with depression symptoms alone. CONCLUSIONS: Adding screening for externalizing problems to existing recommendations for depression screening may help primary care providers to identify a high-risk depressed group of youth for referral to mental health services.

Depression persistence and serotonin transporter genotype in adolescents under usual care conditions.

OBJECTIVES: Polymorphisms of the serotonin transporter (SERT) gene have been shown to influence the risk for depression. The goal of this study was to investigate a possible effect of SERT polymorphisms on severity and course of depression symptoms in a community sample of adolescents. METHODS: Community-dwelling adolescents (n=192) ages 13-17 years, who were at risk for depression, were followed for a period of 6 months. Subjects donated a saliva sample for genotyping of the 5-HTTLPR and STin2 VNTR polymorphisms of SERT. RESULTS: We found no associations between SERT genotype and severity of depressive symptoms at baseline. Depression symptom severity markedly decreased over time. For 5-HTTLPR, we observed a significant interaction between time and genotype, indicating the possibility that heterozygote genotype carriers (s/l) might experience a greater reduction in depression symptoms over time compared with adolescents with the 5-HTTLPR l/l genotype. CONCLUSIONS: Our study shows that for most community-dwelling adolescents, depressive symptoms decrease over time. A possible interaction effect of time and SERT genotype will require confirmation in larger studies.

Predictors of persistence after a positive depression screen among adolescents.

OBJECTIVE: To examine predictors of depression persistence after a positive screening test to inform management protocols for screened youth. METHODS: We conducted a cohort study of 444 youth (aged 13-17 years) from a large health care delivery system. Youth with depressive symptoms, based on a 2-item depression screen, were oversampled for the baseline interview. Baseline assessments included the Patient Health Questionnaire 9-item (PHQ-9) depression screen as well as clinical factors that were hypothesized to influence depression persistence (family history of depression, functional impairment, perceived social support, anxiety symptoms, externalizing symptoms, and medical comorbidity). Logistic regression analysis was used to examine factors associated with the persistence of depression at 6 months postbaseline. RESULTS: Of 113 youth with a positive baseline screen (PHQ-9 ≥11), 47% and 35% continued to be positive at 6-week and 6-month follow-up, respectively. After controlling for treatment status, only 2 factors were significantly associated with depression persistence at 6 months: baseline depressive symptom score and continuing to have a positive screen at 6 weeks. For each 1-point increase on the PHQ-9 score at baseline, youth had a 16% increased odds of continuing to be depressed at 6 months (odds ratio: 1.16, 95% confidence interval: 1.01-1.34). Youth who continued to screen positive 6 weeks later had almost 3 times the odds of being depressed at 6 months (odds ratio: 2.89, 95% confidence interval: 1.09-7.61). CONCLUSIONS: Depressive symptom severity at presentation and continued symptoms at 6 weeks postscreening are the strongest predictors of depression persistence. Patients with high depressive symptom scores and continued symptoms at 6 weeks should receive active treatment.

Fiber-optic scanning two-photon fluorescence endoscope.

We report on the development of a miniature, flexible, fiber-optic scanning endoscope for two-photon fluorescence imaging. The endoscope uses a tubular piezoelectric actuator for achieving two-dimensional beam scanning and a double-clad fiber for delivery of the excitation light and collection of two-photon fluorescence. Real-time imaging of fluorescent beads and cancer cells has been performed.

Biosensing based on two-photon fluorescence measurements through optical fibers.

We have performed two-photon fluorescence detection in a new scheme in which femtosecond laser pulses were delivered thorugh an optical fiber for nonlinear excitation and the emitted fluorescence was collected through the same fiber. Single-mode fibers were determined to give higher detection efficiency than multimode fibers, consistent with theoretical considerations. The utility of fiber-optic sensing based on two-photon fluorescence detection was proved by an experiment that measured the uptake of a targeted drug delivery agent into cultured cancer cells.

In vitro targeting of synthesized antibody-conjugated dendrimer nanoparticles.

This study reports the synthesis and in vitro biological properties of dendrimer-antibody conjugates. The polyamidoamine dendrimer platform was conjugated to fluorescein isothiocyanate as a means to analyze cell binding and internalization. Two different antibodies, 60bca and J591, which bind to CD14 and prostate-specific membrane antigen (PSMA), respectively, were used as model targeting molecules. The binding of the antibody-conjugated dendrimers to antigen-expressing cells was evaluated by flow cytometry, confocal microscopy, and a new two-photon-based optical fiber fluorescence detection system. The conjugates specifically bound to the antigen-expressing cells in a time- and dose-dependent fashion, with affinity similar to that of the free antibody. Confocal microscopic analysis suggested at least some cellular internalization of the dendrimer conjugate. Dendrimer-antibody conjugates are a suitable platform for targeted molecule delivery into antigen-expressing cells.

Detection and analysis of tumor fluorescence using a two-photon optical fiber probe.

The utility of a two-photon optical fiber fluorescence probe (TPOFF) for sensing and quantifying tumor fluorescent signals was tested in vivo. Xenograft tumors were developed in athymic mice using MCA207 cells expressing green fluorescent protein (GFP). The TPOFF probe was able to detect ex vivo fluorescence from excised tumors containing as little as 0.3% GFP-expressing cells. TPOFF results were similar to both flow-cytometric analysis of tumor cells after isolation and suspension, and fluorescence determined by microscope images of cryosectioned tumors. TPOFF was then used to measure GFP fluorescence from tumors in live mice. The fiber probe detected fluorescently-labeled Herceptin antibody targeted to HER2-expressing tumors in severe combined immunodeficient mice. Dendrimer nanoparticles targeted by folic acid and having 6-TAMRA as a fluorescent probe were also used to label KB cell tumors in vivo. The fiber probe documented a fourfold increase in tumor fluorescence in animals that received the targeted dendrimer. These results suggest TPOFF can be used as a minimally invasive system for identifying tumor markers and monitoring drug therapy.