Horizontal transmission of mutans streptococci in children.

It has not been established whether transmission of mutans streptococci occurs between unrelated children older than 4 years of age. The aim of the study was to investigate the possible transmission of mutans streptococci genotypes from child to child in kindergarten. We studied 96 children (ages 5-6 yrs) in three San Francisco Bay Area public schools. Mutans streptococci colonies from each child were isolated from selective culture on Mitis Salivarius Sucrose Bacitracin agar. We used arbitrary primed polymerase chain reactions to determine the mutans streptococci genotypes. Two children (not siblings) in each of the three schools (6%) shared an identical amplitype of S. mutans, unique to each pair. The 19 S. sobrinus amplitypes were found in 12 children, and all were unique to each child. The presence of matching genotypes of S. mutans demonstrates horizontal transmission of this species between unrelated children aged 5-6 years.

Autonomic reactivity and psychopathology in middle childhood.

BACKGROUND: Better indicators are needed for identifying children with early signs of developmental psychopathology. AIMS: To identify measures of autonomic nervous system reactivity that discriminate children with internalising and externalising behavioural symptoms. METHOD: A cross-sectional study of 122 children aged 6--7 years examined sympathetic and parasympathetic reactivity to standardised field-laboratory stressors as predictors of parent- and teacher-reported mental health symptoms. RESULTS: Measures of autonomic reactivity discriminated between children with internalising behaviour problems, externalising behaviour problems and neither. Internalisers showed high reactivity relative to low-symptom children, principally in the parasympathetic branch, while externalisers showed low reactivity, in both autonomic branches. CONCLUSIONS: School-age children with mental health symptoms showed a pattern of autonomic dimorphism in their reactivity to standardised challenges. This observation may be of use in early identification of children with presyndromal psychopathology.

Dissociations between psychobiologic reactivity and emotional expression in children.

Although there are general assumptions that physiological and behavioral indices of emotion are interrelated, empirical research has revealed inconsistent findings with regard to their degree of association, particularly in children. Two studies were conducted to examine the relations between cardiovascular reactivity and emotional behavior. In the first study, 3- to 6-year-olds completed challenging tasks during which measures of their physiological responses and facial expressions were obtained. With age, children's heart rate decreased, vagal tone increased, and facial expressions became slightly more exaggerated. However, children's physiologic reactions were unrelated to their concurrent facial expression when all children were considered, when only boys were considered, and when children extreme in their physiologic reactions were considered. Only among girls was physiologic reactivity moderately associated with concurrent negative expressiveness. In the second study, 4- and 5-year-olds' physiologic reactivity was examined as a predictor of later overt emotional reaction to venipuncture episodes. Children's overt emotional reactions were consistent across repeated venipunctures, and girls were more visibly distressed than boys. As in the first study, physiologic reactivity was generally unrelated to children's behavioral responses. Findings have implications for assumptions about the degree of coupling between biological and behavioral emotional systems in childhood.

Injuries in child care centers: gender-environment interactions.

OBJECTIVES: To examine child characteristics (age, gender) and child care center environments (socioemotional quality, physical safety) that jointly predict injuries for preschool children. METHODS: A two year prospective study of 360 preschool children, ages 2-6 years, was conducted in four urban child care centers. Composite scores for center quality and physical safety were derived from on-site observations, and injury rates were based on teacher reports. Poisson regression analyses examined age, gender, center quality, center safety, and the interactions of gender with quality and safety as predictors of injury incidence over one child year. RESULTS: Age was significantly associated with injury rates, with younger children sustaining higher rates. An interaction between gender and center quality also significantly predicted injury incidence: girls in low quality centers experienced more injuries, while girls in high quality centers sustained fewer injuries than their male peers. Finally, an interaction between gender and center safety showed that girls in high safety centers sustained more injuries than boys, while girls in low safety centers sustained fewer injuries. CONCLUSIONS: Injuries occur even in relatively safe environments, suggesting that in child care settings, the socioemotional context may contribute, along with physical safety, to the incidence of injury events. Further, gender specific differences in susceptibility to environmental influences may also affect children's vulnerability and risks of injuries. The prevention of injuries among preschool children may thus require attention to and modifications of both the physical and socioemotional environments of child care.

Plasma norepinephrine levels, vagal tone index, and flexor reflex threshold in premature neonates receiving intravenous morphine during the postoperative period: a pilot study.

OBJECTIVE: The goal of this study was to evaluate the effects of a single dose of intravenous morphine on postoperative pain in extremely premature neonates after thoracotomy. DESIGN: Descriptive correlational study. PATIENTS: Twenty-four critically ill mechanically ventilated premature neonates with a mean gestational age of 26.1 +/- 2.1 (SD) weeks and a postnatal age of 13.8 +/- 8.1 (SD) days. OUTCOME MEASURES: Plasma norepinephrine (NE) levels, vagal tone index (VTI), and flexor reflex threshold were measured preoperatively, immediately before, and 20 and 60 minutes after the administration of the first postoperative dose of morphine (0.1 mg/kg). RESULTS: One-way repeated-measures ANOVA revealed no significant change in plasma NE levels from baseline levels (df[2,32] = 2.40, p = 0.11). Pre- and postmorphine VTI values were significantly lower than preoperative values (df[3,60] = 6.04, p = 0.0012), but no significant differences were found between pre- and postmorphine VTI values. Neonates (n = 10) who had a flexor reflex response during the postoperative period demonstrated no significant differences in the force required to elicit a flexor reflex across the four measurements (df[3,27] = 0.76, p = 0.53); however, the flexor reflex responses were significantly less vigorous during the postoperative period than at baseline. CONCLUSIONS: Findings from this pilot study suggest that the dose of morphine commonly used to treat postoperative pain in premature neonates does not affect NE, VTI, and flexor reflex threshold values within 1 hour of administration.

The epidemiology of injuries in 4 child care centers.

OBJECTIVES: (1) To describe the pattern of injury in preschool-aged children in 4 child care centers as compared with the results of other studies; (2) to compare injury rates by sex, age, and child care center; and (3) to examine environmental and child factors contributing to injury severity. DESIGN: A 2-year cohort study of 362 preschool-aged children attending 4 urban child care centers. Teachers completed standardized injury forms on the type of injury, body location, site of injury, and contributing factors. RESULTS: During the 2 years of the study, 1886 injuries were reported. The mean and median child injury rate was 6 and 4 injuries per 2000 exposure hours (equivalent to 1 full-time child care year), respectively. The majority of injuries (87%) were minor, occurred during free play (81%) and on the playground (74%), and were precipitated by child-related factors (59%), such as being pushed. Boys had significantly higher median injury rates than girls. Age-adjusted injury rates for each child care center were significantly different by center (F3 = 61, P<.001). While moderate to severe injuries were more often precipitated by combinations of child and environmental factors (chi2(4) = 20, P<.001), minor injuries were usually precipitated by child-related factors. CONCLUSIONS: Injury data from child care centers are important for identifying common risk factors for frequent or severe injury events and for designing injury prevention programs. More research is needed to identify factors contributing to injuries, such as children's behavior and the child care centers' physical and socioemotional environments.

Crowding stress and violent injuries among behaviorally inhibited rhesus macaques.

Environmental stressors and stable individual differences in human behavior have both been implicated etiologically in injuries. Because stress-related injuries are difficult to study experimentally in humans, the authors examined injury incidence in a troop of 21 male and 15 female free-ranging rhesus macaques (Macaca mulatta) before, during, and after a 6-month group confinement. Individual differences in behavioral inhibition to novelty were assessed, using multiple, quantified observations of behavior by 3 independent raters during 3 previous years. Incidence and severity of medically attended injuries were ascertained from veterinary records over a 2-year study period. A 5-fold increase in the incidence of injuries was documented during confinement stress, and an interaction was found between the stressor and behavioral inhibition in the prediction of injury incidence. Highly inhibited animals had significantly higher injury rates during confinement, compared with their uninhibited peers, but equal or lower rates in the low stress periods that preceded and followed confinement. Inhibited individuals appeared to have been specifically targeted for violence during the group stressor but were protected under normative, more predictable conditions.

Social context in developmental psychopathology: recommendations for future research from the MacArthur Network on Psychopathology and Development. The MacArthur Foundation Research Network on Psychopathology and Development.

Accumulating evidence suggests that social contexts in early life have important and complex effects on childhood psychopathology. Spurred by the lack of an explicit operational definition that could guide the study of such effects, we define a social context operationally as "a set of interpersonal conditions, relevant to a particular behavior or disorder and external to, but shaped and interpreted by, the individual child." Building on this definition, we offer a series of recommendations for future research, based on five theoretically derived propositions: (a) Contexts are nested and multidimensional; (b) contexts broaden, differentiate, and deepen with age, becoming more specific in their effects; (c) contexts and children are mutually determining; (d) a context's meaning to the child determines its effects on the child and arises from the context's ability to provide for fundamental needs; and (e) contexts should be selected for assessment in light of specific questions or outcomes. As reflected in an increasingly rich legacy of literature on child development and psychopathology, social contexts appear to influence emerging mental disorders through dynamic, bidirectional interactions with individual children. Future research will benefit from examining not only statistical interactions between child- and context-specific factors, but also the actual transactions between children and contexts and the transduction of contextual influences into pathways of biological mediation. Because adverse contexts exert powerful effects on the mental health of children, it is important for the field to generate new, more theoretically grounded research addressing the contextual determinants of psychological well-being and disorder.

Life events, frontal electroencephalogram laterality, and functional immune status after acute psychological stressors in adolescents.

OBJECTIVE: Past studies have found that environmental stress affects cellular immune function and that extensive variability exists in the magnitude and direction of stress-induced immune changes. Past research also suggests that individuals with greater right, relative to left, resting frontal electroencephalogram (EEG) activation perceive environmental stress as more aversive and have lower baseline cellular immune function. In this study, we examined environmental stressors, resting frontal EEG laterality, and immune responses to short-term psychological stressors in adolescent boys. METHODS: A sample of twenty-four 14-16 year old right-handed boys underwent a recording of resting EEG and collections of blood taken before and after a laboratory protocol designed to induce psychological stress. Blood samples were used to measure changes in mitogen lymphoproliferative responses, natural killer (NK) cell activity, and T-cell phenotypic subsets. Life events were measured using self-report questionnaires. RESULTS: Life events and frontal laterality showed a first order interaction in predicting changes in lymphocyte proliferation to tetanus toxoid (R2 increment = .26, p < .01) and pokeweed mitogen (R2 increment = .25, p < .02). The interaction also predicted changes in NK activity (R2 increment = .24, p < .02). CONCLUSIONS: Changes in lymphocyte proliferation and NK activity were associated with negative life events only among individuals with greater left frontal cortical activation. Our results suggest that recent psychosocial stress and individual differences in resting frontal cortical activation are together linked to immunologic responses to acute psychological stressors.

Tympanic temperature asymmetry and stress behavior in rhesus macaques and children.

OBJECTIVES: To examine left-to-right tympanic membrane temperature asymmetries and their possible association with biobehavioral stress responses in rhesus macaques and children. SUBJECTS AND DESIGN: Infrared tympanic membrane thermometry was completed bilaterally in 19 two-year-old rhesus macaques and 18 eight-year-old children in a cross-sectional, laboratory-based study. Unidirectional temperature gradients were calculated as the mean of two left-sided measurements minus the mean of two right-sided measurements. Biobehavioral stress responses were assessed in monkeys as agitated motor activity and adrenocortical activation after separation from the social group, and in children as parent-reported resilience to psychological stress and child behavior problems. RESULTS: Significant asymmetry was detected in tympanic membrane temperatures in both monkey and child samples, with left-sided temperatures measuring slightly but significantly higher than those from the right tympanic membrane. Higher-magnitude left-to-right temperature gradients were associated with stress-related locomotion in macaques and with lower resilience and more behavior problems in children. CONCLUSIONS: There are small but reliable asymmetries in the tympanic membrane temperatures of young human and nonhuman primates. Tympanic membrane temperature gradients reflect important individual differences in biologically derived responses to psychological stressors.

Resilience and vulnerability among preschool children: family functioning, temperament, and behavior problems.

OBJECTIVE: To examine the effects of child temperament and stressful family functioning on child behavior problems among preschool children. METHOD: One hundred forty-five preschool children, aged 2 to 5 years, were evaluated by teachers, mothers, and independent observers. Teachers reported on child temperament; from these ratings, two dimensions of temperament were derived: difficult/easy and approachability. Mothers reported on two dimensions of family functioning: conflict and expressiveness. Both teachers and independent observers rated child behavior problems. RESULTS: Children with more difficult temperaments who were in high-conflict families had the most internalizing and externalizing behavior problems, while children with easy temperaments had fewer such problems, regardless of levels of family conflict. Difficult children whose families were highly expressive engaged in the most observed aggression. CONCLUSIONS: Results suggest that temperament is involved in both protective and vulnerability processes. A difficult temperament operates as a vulnerability factor for internalizing and externalizing behavior problems and observed aggression, while an easy temperament functions as a protective mechanism for these outcomes.

Life events, cardiovascular reactivity, and risk behavior in adolescent boys.

BACKGROUND: Risk behavior contributes to injuries, one of the most important sources of morbidity and mortality in adolescents. Although research has shown that environmental stress makes adolescents more likely to engage in risk behavior and to sustain injuries, the magnitude of these associations has been small. Little is known about the role of individual differences in psychobiologic reactivity to stress in moderating the impact of stressful events. In this study, we examined associations among environmental stressors, cardiovascular reactivity to stress, and the level of risk behavior in adolescent boys. METHODS: Twenty-four 14- to 16-year-old boys underwent a laboratory protocol designed to measure responses to psychologically and physically stressful tasks. Changes in heart rate and mean arterial blood pressure were measured serially at standard points in the protocol, and levels of positive and negative life events and recent risk behavior were measured using self-report questionnaires. RESULTS: Neither life events nor cardiovascular reactivity were independently associated with risk behavior. Positive life events and mean arterial blood pressure reactivity significantly interacted, however, in predicting risk behavior (R2 increment = .25). Boys with high reactivity who reported numerous positive life events engaged in markedly less risk behavior than their peers. CONCLUSION: We conclude that adolescents with exaggerated cardiovascular responses to laboratory stressors are associated with less risk behavior in a setting of positive life circumstances. This result suggests that reactivity may exert protective, rather than harmful, influences in some environments.

Adrenocortical and behavioral predictors of immune responses to starting school.

Associations between major psychologic stressors and immune function have been documented in previous research, but few studies have investigated immune changes attending minor, normative stressors. This study examined adrenocortical and behavioral predictors of immune responses to starting kindergarten in 39 five-year-old children, who completed laboratory visits for venipunctures 1 wk before (time 1) and 1 wk after (time 2) school entry. At time 1, children were also immunized with pneumococcal vaccine. Immune responses were measured as change scores for T (CD4+ and CD8+) cells, B (CD19+) cells, lymphoproliferative responses to pokeweed mitogen (PWM), and type-specific pneumococcal antibody responses (ABR). Adrenocortical response was assessed as the change in salivary cortisol level, and behavioral difficulty with school adjustment was scored using parental ratings of behavior problems, stress due to changes in routines, and degree of adaptive challenge. Salivary cortisol rose after kindergarten entry (means = 0.39 +/- 0.28 to 0.49 +/- 0.36 micrograms/dL, p = 0.03) and was unrelated to behavioral difficulties. CD4+ cells increased in number, whereas PWM declined, and CD19+ cells showed a borderline increase. Change in salivary cortisol was positively associated with change in CD19+ (delta CD19+) and inversely related to ABR. Scores for behavioral difficulty were inversely associated with delta CD4+ and delta CD19+. These data suggest that: 1) school entry is a stressor capable of evoking elevations in cortisol and behavior problems, accompanied by shifts in functional and enumerative measures of immune status; and 2) children with greater adrenocortical reactivity have increases in B cell numbers and less effective B cell-mediated antibody production, whereas children with more behavioral difficulties show declines in all T and B cell subsets.

Psychobiologic reactivity to stress and childhood respiratory illnesses: results of two prospective studies.

Psychological stress is thought to undermine host resistance to infection through neuroendocrine-mediated changes in immune competence. Associations between stress and infection have been modest in magnitude, however, suggesting individual variability in stress response. We therefore studied environmental stressors, psychobiologic reactivity to stress, and respiratory illness incidence in two studies of 236 preschool children. In Study 1, 137 3- to 5-year-old children from four childcare centers underwent a laboratory-based assessment of cardiovascular reactivity (changes in heart rate and mean arterial pressure) during a series of developmentally challenging tasks. Environmental stress was evaluated with two measures of stressors in the childcare setting. The incidence of respiratory illnesses was ascertained over 6 months using weekly respiratory tract examinations by a nurse. In Study 2, 99 5-year-old children were assessed for immune reactivity (changes in CD4+, CD8+, and CD19+ cell numbers, lymphocyte mitogenesis, and antibody response to pneumococcal vaccine) during the normative stressor of entering school. Blood for immune measures was sampled 1 week before and after kindergarten entry. Environmental stress was indexed with parent reports of family stressors, and a 12-week respiratory illness incidence was measured with biweekly, parent-completed symptom checklists. The two studies produced remarkably similar findings. Although environmental stress was not independently associated with respiratory illnesses in either study, the incidence of illness was related to an interaction between child care stress and mean arterial pressure reactivity (beta = .35, p < .05) in Study 1 and to an interaction between stressful life events and CD19+ reactivity (beta = .51, p < .05) in Study 2.(ABSTRACT TRUNCATED AT 250 WORDS)

Salivary cortisol in nursery-reared rhesus monkeys: reactivity to peer interactions and altered circadian activity.

Five nursery-reared rhesus (Macaca mulatta) infants were studied on 8 consecutive days over a period of 2 weeks when they ranged from 4 to 5.5 months. Saliva cortisol samples were obtained by giving each animal, while in its individual home cage, a 6-in. cotton dental roll pretreated with sugared fruit-drink crystals and dried. Subjects were allowed to mouth the cotton roll for 10 min during each collection period. Saliva was then expressed from the cotton and analyzed by radioimmune assay. Samples were collected at 0830, 1100, 1400, and 1630 hr on each of the 8 days. On four of the days, 2-hr peer socialization sessions were imposed between 1200 and 1400 hr. Significant time-of-day effects were obtained. Values tended to be low at 0830 hr, rising significantly to peak levels at 1100 hr, and then declining over the 1400-hr and 1630-hr sampling periods. All 4 subjects with sufficient samples had higher average cortisol concentrations when the 1400-hr sampling followed peer-socialization sessions, compared to no-socialization days. This difference was only marginally significant by paired t test, however. These results (a) support the feasibility of using noninvasive salivary sampling procedures with infant monkeys, and (b) indicate that salivary cortisol measures are sensitive to daily rhythms. Unexpectedly, the results also raise the possibility that nursery-reared infant rhesus macaques may be phase-delayed in their HPA rhythm, with the morning peak occurring several hours after rather than in the hour before lights-on and the morning feeding.

Biobehavioral comparisons between adopted and nonadopted rhesus monkey infants.

Differences between adopted and nonadopted infant rhesus monkeys were examined, as were differences between biological and foster mothers, in measures of infancy and postinfancy behaviors, maternal-infant interactions, and neuroendocrine and behavioral responses to separations. Newborns were experimentally allocated to continuous postnatal care by either their biological mothers (n = 9) or adoptive, nonbiological mothers (n = 7). Behavioral observations were completed during the neonatal period, during separations at 30 days and 5 months, and from 6 to 18 months of age, when animals were housed in a large social group. Maternal and infant responses to separation stress were assessed using measures of behavioral, adrenocortical, and growth hormone reactivity. Out of 84 possible comparisons, only six achieved statistical significance, a number compatible with the operation of chance. Negligible differences in behavioral and neuroendocrine endpoints were found between adopted and nonadopted mother-infant pairs. These findings lend additional credence to human studies finding no increase in the incidence or severity of mental disorders in adopted children.