Test–Retest Reliability of Self-Reported HIV/STD-Related Measures Among African-American Adolescents in Four U.S. Cities

PurposeTo evaluate the test–retest reliability of self-reported sexuality-related data in a sample of African American adolescents residing in four U.S. cities.MethodsUsing audio computer-assisted self-interviewing (ACASI), 156 African American teens (mean age = 15.5 years) provided data on lifetime and recent sexual behavior, HIV/sexually transmitted disease (STD) testing, and theoretical antecedents of sexual risk behavior on two occasions separated by 2 weeks.ResultsMost self-reports of lifetime sexual behavior and STD/HIV testing were stable across the two assessment points. Test–retest agreement was substantial for dichotomous indices of lifetime sexual behaviors and STD testing (kappas ranging from .61–.87), and for 3-month recall of vaginal sex (kappa = .72) and number of sexual partners (intraclass correlation coefficient [ICC] = .68). Lower reliability estimates emerged for count data of unprotected vaginal sex occasions (ICC = .44). Test–retest reliability estimates for antecedents of sexual risk behavior were highest for a validated measure of HIV-related knowledge (r = .73), but somewhat lower for peer norms (r = .58) and condom use self-efficacy (r = .50).ConclusionsAlthough variability in the stability of self-report data was observed, findings confirm that most sexual behavior, STD and HIV testing history, and psychosocial measures can be assessed reliably among adolescents. Research should continue to identify strategies to enhance the reliability of self-report sexual behavior data from youth at risk for HIV and other sexually transmitted infections.     

Immunogenicity of biologically-derived therapeutics: Assessment and interpretation of nonclinical safety studies

An evaluation of potential antibody formation to biologic therapeutics during the course of nonclinical safety studies and its impact on the toxicity profile is expected under current regulatory guidance and is accepted standard practice. However, approaches for incorporating this information in the interpretation of nonclinical safety studies are not clearly established. Described here are the immunological basis of anti-drug antibody formation to biopharmaceuticals (immunogenicity) in laboratory animals, and approaches for generating and interpreting immunogenicity data from nonclinical safety studies of biotechnology-derived therapeutics to support their progression to clinical evaluation. We subscribe that immunogenicity testing strategies should be adapted to the specific needs of each therapeutic development program, and data generated from such analyses should be integrated with available clinical and anatomic pathology, pharmacokinetic, and pharmacodynamic data to properly interpret nonclinical studies.     

Expecting the worst: observations of reactivity to sound in young children with Williams syndrome

The study examined behavioral reactions to sound, including startle eye blinks, in young children with Williams syndrome (WS) using video-based observational techniques. Participants were 21 children with WS and 20 children with other developmental disabilities of mixed etiology between the ages of 2.5 and 6. Groups were matched for chronological age and developmental level. All children participated in a semi-structured play interaction including exposure to mild intensity sounds as emitted from conventional toys. Overall, 90% of the children in the WS group were observed to exhibit overt behavioral reactivity to mild intensity sounds, compared to only 20% in the mixed etiology group. Examination of the temporal sequence indicated that children with WS generally exhibited these behaviors before exposure to sound stimuli, suggesting a relation to anticipatory anxiety. Children with WS also exhibited significantly greater acoustic startle eye blinks, often viewed as an indication of heightened emotional state. Taken together, the current findings confirm the presence of heightened reactivity to sound in WS, behaviors previously investigated using parent report alone. The observed behaviors and their potential relation to anxiety are also discussed.     

Differences in breast tissue oxygenation following radiotherapy

Tissue perfusion and oxygenation changes following radiotherapy may result from and/or contribute to the toxicity of treatment. Breast tissue oxygenation levels were determined in the treated and non-treated breast 1 year after radiotherapy for breast conserving treatment. Transcutaneous oxygenation varied between subjects in both treated and non-treated breast. Subjects without diabetes mellitus (n = 16) had an average oxygenation level of 64.8 ± 19.9 mmHg in the irradiated breast and an average of 72.3 ± 18.1 mmHg (p = 0.018) at the corresponding location in the control breast. Patients with diabetes (n = 4) showed a different oxygenation pattern, with lower oxygenation levels in control tissue and no decrease in the irradiated breast. This study suggests oxygenation levels in normal tissues vary between patients and may respond differently after radiotherapy.     

Vertebral scalloping in neurofibromatosis type 1: a quantitative approach.

OBJECTIVE: To investigate quantitative differences in vertebral scalloping between children who have scoliosis with and without neurofibromatosis type 1 (NF1). DESIGN: A retrospective study. SETTING: A university-affiliated children's hospital. PATIENTS: Twenty-seven children with scoliosis, 13 of whom had NF1 and 14 of whom did not. METHOD: Existing radiographs of the lumbar vertebrae were used to measure and compare the degree of vertebral scalloping. MAIN OUTCOME MEASURES: The distribution of posterior scalloping ratios in the 2 groups and the most extreme ratio in each subject in each group were compared. RESULTS: Scalloping ratios from the children with NF1 were not normally distributed: 31% had ratios greater than 1.20. Scalloping ratios from the non-NF1 children were normally distributed, with a mean ratio (and standard deviation) of 1.13 (0.03). The distribution between the 2 groups was significantly different (p < 0.05). CONCLUSIONS: In children who have scoliosis but no NF1 there was a range of mild scalloping whereas those with NF1 has severe scalloping. Further studies are needed to determine the possible role of vertebral scalloping in scoliosis severity and progression in children who have NF1.     

Serum magnesium levels in asthmatic patients during acute exacerbations of asthma.

The purpose of this study was to determine whether serum magnesium levels in asthmatic patients during acute exacerbations differ from those of a control population. Twenty-three known asthmatics presenting to the emergency department in acute exacerbation (cases) and 15 nonasthmatic patients (controls) matched for age, sex, race, and socioeconomic status had serum magnesium assays drawn. Admission criteria were: age 18 to 50 years with no history of alcoholism, heart disease, renal disease, or diuretic use. Patients giving a history of pregnancy were excluded. Serum magnesium levels were not significantly different in the two study populations, nor did they correlate with the severity of asthma (mean values: cases, 2.04 +/- 0.159 versus controls, 2.03 +/- 0.134 mg/dL; SD of the difference of the means = .048). An analysis for beta-error demonstrated the true difference of the means to be less than .1 (95% confidence) or less than .13 (99% confidence). In conclusion, serum magnesium levels in asthmatics are not significantly different from those of a control nonasthmatic population. They are not clinically useful for predicting the severity of disease.     

Risk Behavior and Perception Among Youths Residing in Urban Public Housing Developments

The scientific literature and popular media suggest that variations in housing structure and neighborhood influence risk behaviors among youths living in low-income urban communities. To explore the importance of these factors on early sexual intercourse, substance use, drug trafficking, and school truancy, data from a community-based survey, conducted in six public housing developments in a major eastern metropolis, were analyzed. The survey group consisted of 300 youths aged 9 through 15 years. There were minimal differences in three potential mediators of risk behaviors (e.g., perceived social support, parenting style, and perceived risk exposure) and in self-reported adolescent risk behaviors among youths residing in different housing developments and between youths residing in high-rise and in low-rise structures. These findings do not support the hypothesis that within a risk-dense low-income environment, variations in building structure or in neighborhood are associated with differences in adolescent risk behaviors.     

Effects of camber on wheeling efficiency in the experienced and inexperienced wheelchair user

The objective of this study was to determine whether energy costs differed between 0 degrees , 3 degrees , and 6 degrees of camber during steady state overground wheeling. Three subject groups were examined: experienced wheelchair users with disabilities (thoracic lesion level 6 and below), nondisabled individuals with manual wheeling experience, and nondisabled individuals with no manual wheeling experience. Heart rate, rating of perceived exertion, visual analog scale for comfort, and a user preference questionnaire were collected for all subjects. Expired gas analysis data were collected for the group with disabilities. No statistically significant differences emerged in respiratory measures for camber angle or group. A camber of 6 degrees was most preferred in terms of stability on a side slope, hand comfort on the pushrims, maneuverability, and overall preference. Rear-wheel camber angle did not affect the energy expenditure of manual wheelchair propulsion, as measured by cardiopulmonary means. The individual manual wheelchair user's perceived level of comfort should be the determining factor in rear-wheel camber selection.