Investigation of Prx1 protein expression provides evidence for conservation of cardiac-specific posttranscriptional regulation in vertebrates.

Gene targeting experiments have defined that the homeobox gene Prx1 is essential for normal craniofacial, limb, and vascular development. Although its RNA expression pattern is well established, Prx1 protein expression in the developing embryo has not been examined. A novel Prx1 antibody was produced to define the normal Prx1 protein expression pattern in the developing mouse embryo. In craniofacial and limb mesenchyme, Prx1 protein expression is consistent with previously published data on RNA localization. However, a remarkable discrepancy was found in cardiac tissue. Prx1 protein is undetectable in the murine embryonic and adult heart, despite the presence of Prx1 transcripts. These data demonstrate that Prx1 expression is posttranscriptionally regulated. This discrepancy between the presence of Prx1 transcript and the absence of detectable protein was also observed in embryonic chick heart, suggesting conservation of the regulatory mechanism in vertebrates. This observation provides a new explanation of why the Prx null mice lack cardiac malformations.

Immunologic changes occurring at kindergarten entry predict respiratory illnesses after the Loma Prieta earthquake.

Previous studies in adult populations have demonstrated alterations in immune function after psychologically stressful events, and pediatric research has shown significant associations between stress and various childhood morbidities. However, no previous work has examined stress-related immune changes in children and subsequent illness experience. Twenty children were enrolled in a study on immunologic changes after kindergarten entry and their prospective relationship to respiratory illness (RI) experience. Midway through a 12-week RI data collection period, the October 17, 1989 Loma Prieta earthquake occurred. The timing of this event created a natural experiment enabling us to study possible associations between immunologic changes at kindergarten entry, the intensity of earthquake-related stress for children and parents, and changes in RI incidence over the 6 weeks after the earthquake. Immunologic changes were measured using helper (CD4+)-suppressor (CD8+) cell ratios, lymphocyte responses to pokeweed mitogen, and type-specific antibody responses to Pneumovax, in blood sampled 1 week before and 1 week after school entry. RI incidence was assessed using home health diaries and telephone interviews completed every 2 weeks. RIs per child varied from none to six. Six children showed an increase in RI incidence after the earthquake; five experienced a decline. Changes in helper-suppressor cell ratios and pokeweed mitogen response predicted changes in RI incidence in the postearthquake period (r = .43, .46; p < .05). Children showing upregulation of immune parameters at school entry sustained a significant increase in RI incidence after the earthquake.(ABSTRACT TRUNCATED AT 250 WORDS)

After-school child care and self-esteem in school-age children.

Although more than 2 million US children are in self-care after school, little is known of the extent to which self-care may adversely affect developmental processes, such as the development of self-esteem. To test the hypothesis that lower self-esteem is associated with being in self-care, 297 subjects in fourth and sixth grades from three ethnically diverse schools in northern California were enrolled in a cross-sectional study during November 1987. Sixty percent of subjects were in adult in-home care, 13% in adult out-of-home care, 19% in self-care, and 8.0% in older sibling care. No significant differences in self-competence scores, as measured by the Harter Self-perception Profile for Children, were observed for children in self-care compared with the three other care groups. However, children who were cared for by older siblings unexpectedly exhibited lower self-competence scores for five of the six self-competence domains, with three domains showing significance at P less than .05. Children in self-care were significantly more isolated socially than children in adult care, reporting fewer opportunities to play outside or have friends visit at their homes. The results indicate that children in sibling care may be at potentially greater risk for negative effects on self-esteem and social development. Children in self-care may also experience more social isolation after school than children in other forms of afterschool care.

Psychosocial predictors of maternal and infant health among adolescent mothers.

Past work suggests that stressful life events and social support are significantly associated with a broad range of child health outcomes. Such associations have remained, however, generally modest in magnitude, suggesting that stress and support may be only proxy measures for a deeper, more central aspect of childhood psychosocial experience. One aspect of young people's lives that could plausibly mediate the effects of stress and social support on health is the sense of stability and "permanence" in ongoing life experience. We developed a standardized psychometric instrument for measuring a "sense of permanence" and employed the measure in a prospective 1-year study of health outcomes among 89 adolescent mothers and their infants. Psychosocial and demographic factors were significantly predictive of maternal, but not infant, health outcomes, and the sense of permanence appeared to operate as a "final common pathway" in the influence of psychosocial variables on health and illness end points. Results of the study underscore the importance of continuity and stability in childhood and suggest that changes in an individual's sense of permanence may underlie the previously documented health effects of stressful life events and social support.

Home care for ventilator-dependent children. Psychosocial impact on the family.

The impact of providing home care for ventilator-dependent children was studied in a cross-sectional survey of 18 northern California families. Through the use of a confidential structured interview and the impact on Family Scale, we obtained information on family demographics; the childrens' medical conditions; financial, social, and personal impact on the family; and parental coping-mastery of the care of a ventilator-dependent child at home. Analysis of scores from the impact on Family Scale showed no differences in the perceived family impact between primary caretakers and their spouses. Primary caretakers in the sample, however, showed significantly reduced Coping subscale scores with a longer duration of home ventilatory care. This finding, if confirmed in future studies, has policy implications for physicians and other health professionals working with ventilator-dependent children and their families, especially those who care for children over long periods.

Life events, social support, and cardiovascular reactivity in adolescence.

Physiologic responses to environmental stress show striking interindividual differences, beginning early in life. Whereas cardiovascular reactivity (CVR) to stress has been linked to short- and long-term changes in health, little previous work has addressed reactivity in children, and no past studies have investigated the relationship of reactivity to psychosocial factors, such as stressful life events (LE) and social support (SS). We therefore studied cardiovascular response to psychologically and physically stressful laboratory tasks in 25 adolescent boys. The degree of individual CVR was examined cross-sectionally in relationship to LE, SS, and "sense of permanence" (SP), a construct reflecting the stability or continuity in the child's life experience. Heart rate reactivity (HRR) and mean arterial pressure reactivity (BPR) were bimodally distributed, with a subpopulation of approximately 20% of subjects demonstrating an exaggerated cardiovascular response. SP was related to BPR at a borderline level of significance (R = 0.33, p less than 0.10), whereas SS was unrelated to either reactivity variable. Unexpectedly, LE was strongly and inversely related to both HRR and BPR (R = -0.40 and -0.47, respectively, p less than 0.05). Subjects reporting low numbers of previous stressful life events had the highest level of cardiovascular reactivity. Possible explanations for this finding included (1) the development of a hyperdynamic response as a consequence of avoiding or denying stressful experience, (2) an effect of exaggerated CVR on cognition and the reporting of stressful events, or, most plausibly, (3) an 'inoculation effect,' in which previous LE facilitate the development of effective coping strategies, thereby diminishing responses to stressful laboratory tasks.