Carl M. Brezausek

Cocaine inhibits NGF-induced PC12 cells differentiation through D1-type dopamine receptors

In utero cocaine exposure can adversely affect CNS development. Previous studies showed that cocaine inhibits neuronal differentiation in a dose-dependent fashion in nerve growth factor (NGF)-stimulated PC12 cells. Cocaine binds with high affinity to several neurotransmitter transporters, resulting in elevated neurotransmitter levels in nerve endings. To determine if cocaine inhibits neurite outgrowth through the effects of these neurotransmitters, we applied dopamine, norepinephrine, serotonin, and acetylcholine to NGF-induced PC12 cells. Dopamine was the only neurotransmitter to inhibit neurite outgrowth significantly in a dose-dependent pattern without affecting cell viability. Norepinephrine and acetylcholine did not affect neurite outgrowth, while serotonin enhanced it. Furthermore, GBR 12909, a potent dopamine transporter (DAT) inhibitor, yielded similar effects. We then showed PC12 cells express D(1) and D(2) receptors and DAT proteins. Dopamine uptake measured over time was significantly blocked by cocaine and GBR 12909 which may result in elevated extracellular dopamine. The role of dopamine receptors in PC12 differentiation was further examined by using D(1) and D(2) specific receptor agonists. Only the D(1) agonist, SKF-38393, had a significant dose-dependent inhibitory effect. In addition, a D(1) antagonist produced significant recovery of neurite outgrowth in cocaine-treated cells. These findings suggest that cocaine inhibitory effects on neuronal differentiation are mediated through its binding to the dopamine transporter, resulting in increased dopamine level in the synapses. Subsequently, up regulation of D(1) receptors alters NGF signaling pathways.

Head Start Children Finishing First Grade: Preliminary Data on School Identification of Children at Risk for Special Education.

Although Head Start has a mandate to serve children with disabilities as at least 10% of its population, few systematic data are available on identification of children in various disability categories in the years immediately following their preschool experience. In the study reported here, two cohorts of 4,161 children across 30 sites were followed through first grade as part of a larger study on transition assistance. At-risk status was assessed at the beginning of kindergarten by developing research diagnostic criteria (RDC) for four major special education categories using clinical cut-off points on language, achievement, and social skills measures and indicators of speech or mental health problems on parent interviews. The school identification of study participants in each RDC was determined by a search of school archival records in the spring of first grade. Only 26% of the children meeting RDC in the four major categories were identified by the schools, and little concordance was observed among categories. Findings are discussed in relation to disability categories, with particular reference to assumptions about underidentification of children with emotional or behavioral disorders.

Children at Risk: Effects of a Four-Year Head Start Transition Program on Special Education Identification

Children in Head Start are at risk for school learning or behavioral problems. While Head Start has decreased special education placement, there has been little systematic data until recently on identification of children in disability categories following preschool. In this study, two cohorts of 6,162 children across 30 sites were followed through third grade. Approximately half of these children were provided transition assistance from kindergarten through third grade. This included school transition and curricular modifications, parent involvement activities, health screening or referrals, and family social services, all similar to those received in Head Start. They were compared to a similar group of Head Start children who did not receive such services beyond the Head Start experience. Special education eligibility was determined from school records in the spring of third grade. Only 0.89% of children in the transition group were identified in the mental retardation category compared to 1.26% in the non-transition group. In the category of emotional disturbance, these same figures were 1.21% and 1.65% respectively. Both differences were statistically significant, but an opposite effect was found in the category of speech or language impairment. Findings are discussed in relation to differences in disability categories and implications for early identification.

Injury risk among children of low-income U.S.-born and immigrant mothers.

The number of immigrants in the United States is at an all time high, yet psychologists have largely ignored the domain of immigrant health. This article considers 1 aspect of immigrant health, risk for pediatric injury. A sample of over 5,000 5-year-old children from impoverished families was studied; approximately 13% had immigrant mothers. Children of immigrants had a significantly lower rate of injury in the prior year. This was particularly true of non-White children of immigrants. Three possible mediators for this finding--assistance with parenting, parenting style, and health care accessibility--were considered, but none explained the difference. The need for further research on the topic and implications of results for injury prevention are discussed.

Head Start Children at Third Grade: Preliminary Special Education Identification and Placement of Children with Emotional, Learning, and Related Disabilities

Although children in Head Start are at risk for emotional or behavioral problems, little is known about their later need for special education. There is evidence that children at risk for emotional disturbance are underidentified or misidentified in other special education categories. We examined special education identification rates for Head Start children at risk for emotional disturbance, learning disabilities, speech or language impairments, and mental retardation as they complete third grade. Two cohorts of 4136 children across 30 sites were followed as part of a larger study on transition. Diagnosis of each child as being at risk for emotional disturbance or related disabilities was made using clinical cut-offs on teacher ratings and individual testing completed in the spring of third grade. Special education eligibility of these children was determined from school records. Only 31.8% of children considered to be at risk, based on research diagnostic criteria, were actually identified by the schools, and fewer than 6% of children at risk for ED were identified in the school category of ED. Comparisons were made between school-identified and nonidentified children in gender, ethnicity, and school variables; and findings were discussed in relation to underidentification or misidentification of children with emotional disturbance.

The Role of Context in Risk for Pediatric Injury: Influences from the Home and Child Care Environments

Unintentional injury is the leading cause of pediatric mortality among American children, but the role of environmental context remains poorly understood as a risk for child injury. Couched in Bronfenbrenners (1977) ecological theory, this study analyzed data from a sample of almost 900 children to identify relations between the home and out-of-home child care environments and subsequent risk for injury. Results suggest that both child- and supervisor-oriented factors, as measured at 36 months, predicted childrens injuries over the subsequent three years. The role of the mesosystem was supported: parent-related factors predicted childrens subsequent injuries in child care and school settings, and child care provider experience predicted childrens subsequent injuries at home. Results are discussed from the perspectives of ecological theory and implications for injury prevention.

Child Development and Pediatric Sport and Recreational Injuries by Age

CONTEXT In 2010, 8.6 million children were treated for unintentional injuries in American emergency departments. Child engagement in sports and recreation offers many health benefits but also exposure to injury risks. In this analysis, we consider possible developmental risk factors in a review of age, sex, and incidence of 39 sport and recreational injuries. OBJECTIVE To assess (1) how the incidence of 39 sport and recreational injuries changed through each year of child and adolescent development, ages 1 to 18 years, and (2) sex differences. Design : Descriptive epidemiology study. SETTING Emergency department visits across the United States, as reported in the 2001-2008 National Electronic Injury Surveillance System database. PATIENTS OR OTHER PARTICIPANTS Data represent population-wide emergency department visits in the United States. Main Outcome Measure(s) : Pediatric sport- and recreation-related injuries requiring treatment in hospital emergency departments. RESULTS Almost 37 pediatric sport or recreational injuries are treated hourly in the United States. The incidence of sport- and recreation-related injuries peaks at widely different ages. Team-sport injuries tend to peak in the middle teen years, playground injuries peak in the early elementary ages and then drop off slowly, and bicycling injuries peak in the preteen years but are a common cause of injury throughout childhood and adolescence. Bowling injuries peaked at the earliest age (4 years), and injuries linked to camping and personal watercraft peaked at the oldest age (18 years). The 5 most common causes of sport and recreational injuries across development, in order, were basketball, football, bicycling, playgrounds, and soccer. Sex disparities were common in the incidence of pediatric sport and recreational injuries. CONCLUSIONS Both biological and sociocultural factors likely influence the developmental aspects of pediatric sport and recreational injury risk. Biologically, changes in perception, cognition, and motor control might influence injury risk. Socioculturally, decisions must be made about which sport and recreational activities to engage in and how much risk taking occurs while engaging in those activities. Understanding the developmental aspects of injury data trends allows preventionists to target education at specific groups.

How Do Mothers and Fathers Influence Pediatric Injury Risk in Middle Childhood

OBJECTIVES Parental influences are among the strongest behavioral correlates to unintentional injury outcome in early childhood, but are less well understood as children develop. We implemented a prospective research design to study how parenting style, parent-child relationships, and parental mental health influence injury during middle childhood. We also considered the roles of parent and child gender. METHODS Parental influences were assessed from a sample of 584 first graders, plus their mothers and fathers. Injuries requiring medical treatment were assessed regularly over the subsequent 5 years. Logistic regression models examined how maternal and paternal parenting factors predicted injury among all children, just boys, and just girls. RESULTS Fathers who reported more positive relationships with their children had children protected from injury. This was particularly true of father-son relationships. No maternal traits predicted injury. CONCLUSIONS A positive father-child, and especially a positive father-son relationship, may protect children from injury during middle childhood.

Language Acculturation and Pediatric Injury Risk

The number of immigrant children in the US continues to grow rapidly, but pediatric immigrant health remains a poorly understood domain. Previous research suggests immigrant children have reduced risk for injury, but the reason for that finding remains unknown. One leading hypothesis is cultural—less acculturated children in the United States appear to be protected from injury—but the combined influence of immigrant status and acculturation is unclear. This study examines the roles of immigration and language acculturation on pediatric injury risk. Samples of 8,526 children and 4,010 adolescents included in the 2003 California Health Interview Survey were studied. The primary analytic technique was Poisson regressions predicting incidents of injury requiring professional medical attention. Predictor variables included demographic characteristics, health insurance availability, birthplace (US vs. other), and language acculturation. Both birthplace and language acculturation were related to children’s and to adolescent’s risk for unintentional injury, but language acculturation emerged as the stronger univariate predictor and only multivariate predictor of injury in both models. Possible interpretations of the results are discussed.

Unintentional injury among low-income 5-year-olds with chronic health conditions

Background: Growing numbers of children suffer from chronic health conditions, and initial evidence suggests chronic illness may be associated with increased child injury risk. We examined injury risk among 5-year-olds with and without chronic health conditions. Methods: Data from a diverse US sample of 7954 low-income 5-year-olds participating in the National Head Start/Public School Early Childhood Transition Demonstration Study were analysed. Mothers reported demographics, presence/absence of eight chronic health conditions, and whether children had experienced injuries requiring professional medical attention in the past year. Primary analyses used ordinal logistic regression. Results: Asthma, bronchitis, recurrent ear infections, hay fever/allergies and speech problems associated with increased injury risk (OR range = 1.20—1.49 in bivariate ordinal logistic regression, ps < 0.01). Children with cerebral palsy had reduced injury risk (OR = 0.37, 95% CI = 0.15—0.91, p < 0.05). Most findings held after including demographic covariates in multivariate models. Conclusion: Because a range of chronic health conditions associated with increased injury risk, the causal mechanism behind relations between chronic illness and injury risk may not be disease-specific. Instead, factors related to having chronic medical conditions—not any particular condition—might contribute. Possible mediators include impaired family functioning, impaired peer relations, and familiarity with the health system/health-seeking behaviours.