Effects of a school readiness intervention on electrophysiological indices of external response monitoring in children in foster care

This study examined the impact of a school readiness intervention on external response monitoring in children in foster care. Behavioral and event-related potential (ERP) data were collected during a flanker task from children who received the Kids In Transition to School (KITS) Program (n = 26) and children who received services as usual (n = 19) before and after the intervention. While there were no significant group differences on the behavioral data, the ERP data for the two groups of children significantly differed. Specifically, in contrast to the children who received services as usual, the children who received the KITS Program displayed greater amplitude differences between positive and negative performance feedback over time for the N1, which reflects early attention processes, and feedback-related negativity, which reflects evaluation processes. In addition, although the two groups did not differ on amplitude differences between positive and negative performance feedback for these ERP components before the intervention, the children who received the KITS Program displayed greater amplitude differences than the children who received services as usual after the intervention. These results suggest that the KITS Program had an effect on responsivity to external performance feedback, which may be beneficial during the transition into kindergarten.

Relations between catechol-O-methyltransferase Val158Met genotype and inhibitory control development in childhood

The Val158Met rs4680 single-nucleotide polymorphism (SNP) at the catechol-O-methyltransferase (COMT) gene, primarily involved in dopamine breakdown within prefrontal cortex, has shown relations with inhibitory control (IC) in both adults and children. However, little is known about how COMT genotype relates to developmental trajectories of IC throughout childhood. Here, our study explored the effects of the COMT genotype (Val/Val, Val/Met, and Met/Met) on IC trajectories between the ages of 5 and 10 years. Children (n = 222) completed a Go/Nogo task at ages 5, 7, and 10; IC was characterized using signal detection theory to examine IC performance (d') and response strategy (RS) (criterion). COMT genotype was not related to initial levels of IC performance and RS at age 5 or change in RS from ages 5 to 10. In contrast, COMT genotype was related to change in IC performance between 5 and 10 years. While Val/Val children did not differ from Val/Met children in development of IC performance, children with the Met/Met genotype exhibited more rapid development of IC performance when compared with Val/Met peers. These results suggest that COMT genotype modulates the development of IC performance in middle childhood.

Development of inhibitory control during childhood and its relations to early temperament and later social anxiety: unique insights provided by latent growth modeling and signal detection theory

BACKGROUND

Children with the temperament of behavioral inhibition (BI) face increased risk for social anxiety. However, not all children with BI develop anxiety symptoms. Inhibitory control (IC) has been suggested as a moderator of the pathway between BI and social anxiety. This study uses longitudinal data to characterize development of IC and tests the hypothesis that IC moderates associations between early BI and later social anxiety symptoms.

METHODS

Children completed a Go/Nogo task at ages 5, 7, and 10 years as part of a longitudinal study of BI (measured at 2-3 years) and social anxiety symptoms (measured at 12 years). To assess IC development, response strategy (criterion) and inhibitory performance (d') were characterized using signal detection theory. Latent growth models were used to characterize the development of IC and examine relations among BI, IC parameters, and social anxiety symptoms.

RESULTS

IC response strategy did not change between 5 and 10 years of age, whereas IC performance improved over time. BI scores in toddlerhood predicted neither initial levels (intercept) nor changes (slope) in IC response strategy or IC performance. However, between ages 5 and 10, rate of change in IC performance, but not response strategy, moderated relations between BI and later parent-reported social anxiety symptoms. Specifically, greater age-related improvements in IC performance predicted higher levels of social anxiety in high BI children.

CONCLUSIONS

IC development in childhood occurs independent of BI levels. However, rapid increases in IC performance moderate risk for social anxiety symptoms in children with BI. Implications for theory and practice are discussed.

Improving kindergarten readiness in children with developmental disabilities: Changes in neural correlates of response monitoring

Among children diagnosed with developmental delays, difficulties in self-regulation are prominent and have been linked to school readiness problems. The current study sought to examine the impact of the Kids in Transition to School (KITS) school readiness intervention program on self-regulation, with a specific focus on response monitoring skills, among children with developmental delays. Children (n = 20 in the KITS group and n = 21 in a services as usual group) were administered a flanker task during which event-related potential data were collected to examine group differences in response monitoring. Findings indicated that children in the KITS group showed significant enhancement of a neural index of response monitoring post-intervention. Specifically, the KITS group showed a significant change in the magnitude of their feedback-related negativity in response to negative performance feedback from baseline to post-intervention, whereas children in the services as usual group did not. There were no significant differences between the groups for the error-related negativity or the error-related positivity on incorrect trials nor were there group differences in behavioral performance on the task at the post-intervention assessment. Overall, these findings provide support for the plasticity of response monitoring skills in young children and support the growing literature demonstrating improved self-regulation outcomes via intervention that enhances children's response monitoring.

The effects of early foster care intervention on attention biases in previously institutionalized children in Romania

Children raised in institutions experience psychosocial deprivation that can negatively impact attention skills and emotion regulation, which subsequently may influence behavioral regulation and social relationships. The current study examined visual attention biases in 8-year-old children who were part of the Bucharest Early Intervention Project (BEIP). Relations among attention biases and concurrent social outcomes were also investigated. In early childhood, 136 children abandoned at birth or shortly thereafter into institutional care were randomized to receive a high-quality foster care intervention or care-as-usual within the context of the Bucharest Early Intervention Project (BEIP). At 8 years of age, 50 care-as-usual, 55 foster care, and 52 community controls performed a behavioral dot-probe task, and indices of attention biases to threat and positive stimuli were calculated. Concurrent data on social behavior were collected. Children placed into the foster care intervention had a significant attention bias toward positive stimuli, while children who received care-as-usual had a significant bias toward threat. Children in the foster care intervention had a significantly larger positive bias when compared to the care-as-usual group. A positive bias was related to more social engagement, more prosocial behavior, less externalizing disorders, and less emotionally withdrawn behavior. The magnitude of positive bias was predicted by age of placement into foster care among children with a history of institutionalization. An attention bias towards positive stimuli was associated with reduced risk for behavioral problems amongst children who experienced early psychosocial deprivation. Research assessing attention biases in children experiencing early environmental stress may refine our understanding of the mechanisms underlying risk for later psychiatric and social disorders and inform prevention efforts.

Cognitive control moderates early childhood temperament in predicting social behavior in 7-year-old children: an ERP study

Behavioral inhibition (BI) is a temperament associated with heightened vigilance and fear of novelty in early childhood, and social reticence and increased risk for anxiety problems later in development. However, not all behaviorally inhibited children develop signs of anxiety. One mechanism that might contribute to the variability in developmental trajectories is the recruitment of cognitive-control resources. The current study measured N2 activation, an ERP (event-related potential) associated with cognitive control, and modeled source-space activation (LORETA; Low Resolution Brain Electromagnetic Tomography) at 7 years of age while children performed a go/no-go task. Activation was estimated for the entire cortex and then exported for four regions of interest: ventromedial prefrontal cortex (VMPFC), ventrolateral prefrontal cortex (VLPFC), dorsal anterior cingulate cortex (dorsal ACC), and dorsal lateral prefrontal cortex (DLPFC). BI was measured in early childhood (ages 2 and 3 years). Anxiety problems and social reticence were measured at 7 years of age to ascertain stability of temperamental style. Results revealed that BI was associated with increased performance accuracy, longer reaction times, greater (more negative) N2 activation, and higher estimated dorsal ACC and DLPFC activation. Furthermore, early BI was only associated with social reticence at age 7 at higher (more negative) levels of N2 activation or higher estimated dorsal ACC or DLPFC activation. Results are discussed in the context of overcontrolled behavior contributing to social reticence and signs of anxiety in middle childhood.

Psychosocial deprivation, executive functions, and the emergence of socio-emotional behavior problems

Early psychosocial deprivation can negatively impact the development of executive functions (EFs). Here we explore the impact of early psychosocial deprivation on behavioral and physiological measures (i.e., event-related potentials; ERPs) of two facets of EF, inhibitory control and response monitoring, and their associations with internalizing and externalizing outcomes in the Bucharest Early Intervention Project (BEIP; Zeanah et al., 2003). This project focuses on two groups of children placed in institutions shortly after birth and then randomly assigned in infancy to either a foster care intervention or to remain in their current institutional setting. A group of community controls was recruited for comparison. The current study assesses these children at 8-years of age examining the effects of early adversity, the potential effects of the intervention on EF and the role of EF skills in socio-emotional outcomes. Results reveal exposure to early psychosocial deprivation was associated with impaired inhibitory control on a flanker task. Children in the foster care intervention exhibited better response monitoring compared to children who remained in the institution on the error-related positivity (Pe). Moreover, among children in the foster care intervention those who exhibited larger error-related negativity (ERN) responses had lower levels of socio-emotional behavior problems. Overall, these data identify specific aspects of EF that contribute to adaptive and maladaptive socio-emotional outcomes among children experiencing early psychosocial deprivation.

Emotion recognition following early psychosocial deprivation

An important function of the brain is to scan incoming sensory information for the presence of relevant signals and act on this information. For humans, the most salient signals are often social in nature, such as the identity and the emotional expression of the faces we encounter in our everyday lives. It can be argued that our survival as a species depends in large measure on these skills.

Neural activation underlying cognitive control in the context of neutral and affectively charged pictures in children

The neural correlates of cognitive control for typically developing 9-year-old children were examined using dense-array ERPs and estimates of cortical activation (LORETA) during a go/no-go task with two conditions: a neutral picture condition and an affectively charged picture condition. Activation was estimated for the entire cortex after which data were exported for four regions of interests (ROIs): ventrolateral prefrontal cortex (VLPFC), dorsal anterior cingulate cortex (dACC), dorsolateral prefrontal cortex (DLPFC), and orbitofrontal/ventromedial prefrontal cortex (OFC/VMPFC). Results revealed faster reaction times, greater N2 activation, and greater prefrontal activation for the affectively charged picture condition than the neutral picture condition. The findings are discussed in reference to the impact of affective stimuli on recruitment of specific brain regions involved in cognitive control.

Attention biases to threat link behavioral inhibition to social withdrawal over time in very young children

Behaviorally inhibited children display a temperamental profile characterized by social withdrawal and anxious behaviors. Previous research, focused largely on adolescents, suggests that attention biases to threat may sustain high levels of behavioral inhibition (BI) over time, helping link early temperament to social outcomes. However, no prior studies examine the association between attention bias and BI before adolescence. The current study examined the interrelations among BI, attention biases to threat, and social withdrawal already manifest in early childhood. Children (N=187, 83 Male, M (age)=61.96 months) were characterized for BI in toddlerhood (24 & 36 months). At 5 years, they completed an attention bias task and concurrent social withdrawal was measured. As expected, BI in toddlerhood predicted high levels of social withdrawal in early childhood. However, this relation was moderated by attention bias. The BI-withdrawal association was only evident for children who displayed an attention bias toward threat. The data provide further support for models associating attention with socioemotional development and the later emergence of clinical anxiety.

Behavioral inhibition and anxiety: the moderating roles of inhibitory control and attention shifting

Behavioral inhibition (BI), a temperament identified in early childhood, is associated with social reticence in childhood and an increased risk for anxiety problems in adolescence and adulthood. However, not all behaviorally inhibited children remain reticent or develop an anxiety disorder. One possible mechanism accounting for the variability in the developmental trajectories of BI is a child's ability to successfully recruit cognitive processes involved in the regulation of negative reactivity. However, separate cognitive processes may differentially moderate the association between BI and later anxiety problems. The goal of the current study was to examine how two cognitive processes-attention shifting and inhibitory control-laboratory assessed at 48 months of age moderated the association between 24-month BI and anxiety symptoms in the preschool years. Results revealed that high levels of attention shifting decreased the risk for anxiety problems in children with high levels of BI, whereas high levels of inhibitory control increased this risk for anxiety symptoms. These findings suggest that different cognitive processes may influence relative levels of risk or adaptation depending upon a child's temperamental reactivity.

Attention biases to threat and behavioral inhibition in early childhood shape adolescent social withdrawal

Behavioral inhibition (BI) is a temperament characterized in young children by a heightened sensitivity to novelty, social withdrawal, and anxious behaviors. For many children, these social difficulties dissipate over time. For others, patterns of social withdrawal continue into adolescence. Over time, attention biases to threat may influence the stability of BI and its association with social withdrawal, ultimately modulating the risk for anxiety disorders in BI children. However, we know relatively little about the cognitive processes that accompany BI and shape later socio-emotional functioning. We examined the relations among BI in childhood, attention biases to threat in adolescence, and adolescent social withdrawal in a longitudinal study (N = 126, Mean age = 15 years). As has been reported in anxious adults, adolescents who were behaviorally inhibited as toddlers and young children showed heightened attention bias to threat. In addition, attention bias to threat moderated the relation between childhood BI and adolescent social withdrawal.

Anger and Approach Motivation in Infancy: Relations to Early Childhood Inhibitory Control and Behavior Problems

The relations among infant anger reactivity, approach behavior, and frontal EEG asymmetry, and their relations to inhibitory control and behavior problems in early childhood were examined within the context of a longitudinal study of temperament. Two hundred and nine infants' anger expressions to arm restraint were observed at 4 months of age. Infants' approach behaviors during play with an unpredictable toy and baseline frontal electroencephalogram (EEG) asymmetry were assessed at 9 months of age. Inhibitory control during a Go/No-Go task and parent-report of behavior problems were evaluated at 4 years of age. High anger-prone infants with left, but not right, frontal EEG asymmetry showed significantly more approach behaviors and less inhibitory control relative to less anger-prone infants. Although a link between anger proneness in infancy and behavior problems in early childhood was not found, a combination of low approach behaviors and poor inhibitory control was predictive of internalizing behaviors.

Variations in the serotonin-transporter gene are associated with attention bias patterns to positive and negative emotion faces

Both attention biases to threat and a serotonin-transporter gene polymorphism (5-HTTLPR) have been linked to heightened neural activation to threat and the emergence of anxiety. The short allele of 5-HTTLPR may act via its effect on neurotransmitter availability, while attention biases shape broad patterns of cognitive processing. We examined individual differences in attention bias to emotion faces as a function of 5-HTTLPR genotype. Adolescents (N=117) were classified for presumed SLC6A4 expression based on 5-HTTLPR-low (SS, SL(G), or L(G)L(G)), intermediate (SL(A) or L(A)L(G)), or high (L(A)L(A)). Participants completed the dot-probe task, measuring attention biases toward or away from angry and happy faces. Biases for angry faces increased with the genotype-predicted neurotransmission levels (low>intermediate>high). The reverse pattern was evident for happy faces. The data indicate a linear relation between 5-HTTLPR allelic status and attention biases to emotion, demonstrating a genetic mechanism for biased attention using ecologically valid stimuli that target socioemotional adaptation.

Using behavioral and electrophysiological measures to assess the effects of a preventive intervention: a preliminary study with preschool-aged foster children

The current study was designed to explore the use of behavioral (i.e., accuracy and reaction times) and electrophysiological measures (i.e., event-related potentials) to assess the impact of a family-based preventive intervention for preschool-aged, maltreated children in foster care. These measures were recorded during a computerized flanker task designed to assess cognitive control and response monitoring. The sample was recruited from a larger randomized efficacy trial of Multidimensional Treatment Foster Care for Preschoolers (MTFC-P) and included foster children assigned to the intervention condition (n = 10), foster children assigned to a services-as-usual comparison condition (n = 13), and low-income, nonmaltreated community children (n = 11). The children's behavioral and electrophysiological performance on the task was generally consistent with previous research with adults and older children. There were no group differences on the behavioral measures of cognitive control or response monitoring. Notably, however, group differences were observed on the electrophysiological measures of response monitoring. Specifically, the foster children who received services as usual were significantly less responsive to performance feedback about errors than the foster children who received the intervention and the nonmaltreated children. Applications of this methodology and implications of the results for future prevention research are discussed.

Variations of the flanker paradigm: assessing selective attention in young children

The development of selective attention and associated self-regulatory processes was assessed in young children, ages 4, 5, and 6, through the use of three alternative versions of the flanker paradigm utilizing colors, shapes, and fish. These variations were used to examine the influence of task differences on children's performance. The presence of cognitive self-regulatory strategies in young children was also assessed. Significant flanker interference effects, marked by significant task-linked response time differences, were found across all three versions of the paradigm. Although a significant portion of children demonstrated self-regulatory abilities, not every participant demonstrated the specific strategies of self-monitoring and response control. Furthermore, these differences were evident across all age groups. The implications of these results are discussed within the theoretical context of task development, taking into consideration the need to modify computerized attention paradigms for use with young children in order to reliably measure cognitive constructs across children and adults.

Does inadequate prenatal care contribute to growth retardation among second-born African-American babies?

The authors evaluated the relation between adequacy of prenatal care and risk of delivery of full term small-for-gestational-age (SGA) infants. Data were derived from maternally linked birth certificates for 6,325 African-American women whose first two pregnancies ended in singleton, full term live births in Georgia from 1989 through 1992. The authors used stratified analysis to assess the effect of prenatal care on the risk of having an SGA baby in the second pregnancy among women with and without an SGA baby in their first pregnancy. The group of women with a history of SGA birth may be more likely to include persons for whom SGA delivery is related to factors, such as genetics, that are not amenable to intervention by prenatal care. Inadequate prenatal care was not associated with the risk of SGA delivery among women who had previously delivered an SGA baby. In unadjusted analyses, inadequate prenatal care was associated with an increased risk of delivering a full term SGA baby in the second pregnancy among women whose first baby was not SGA (risk ratio = 1.28; 95% confidence interval: 1.05, 1.55). The association did not persist when data were adjusted for confounding variables (odds ratio = 1.11; 95% confidence interval: 0.89, 1.38). Regardless of outcome in the first pregnancy, adequate prenatal care did not reduce the risk of full term SGA birth among second pregnancies in this population.

High Genetic Similarity Among Populations of Phaeosphaeria nodorum Across Wheat Cultivars and Regions in Switzerland

ABSTRACT Phaeosphaeria nodorum was sampled from nine wheat fields across a 30-km transect representing three geographical regions in Switzerland to determine the scale of genetic differentiation among subpopulations. Three different wheat cultivars were sampled three times to determine whether differences in host genotype correlated with differences among corresponding pathogen populations. Seven restriction fragment length polymorphism (RFLP) loci and one DNA fingerprint were assayed for each of the 432 isolates in the collection. DNA fingerprints differentiated 426 unique genotypes. Though absolute differences were small, five RFLP loci exhibited significant differences in allele frequencies across the nine sub-populations. Gene diversity within all subpopulations was high (H(T) = 0.51), but only 3% of the total genetic variation was distributed among the nine subpopulations. When subpopulations were grouped according to geographical region or host cultivar, less than 1% of the genetic variation was distributed among groups, suggesting widespread gene flow and the absence of pathogen adaptation to specific wheat cultivars. Tests for gametic equilibrium within subpopulations and across the entire Swiss population supported the hypothesis of random mating.

Gene Flow and Sexual Reproduction in the Wheat Glume Blotch Pathogen Phaeosphaeria nodorum (Anamorph Stagonospora nodorum)

ABSTRACT Restriction fragment length polymorphisms (RFLPs) were used to characterize the genetic structures of three field populations of Phaeosphaeria nodorum from Texas, Oregon, and Switzerland. Data from seven nuclear RFLP loci were used to estimate gene diversity and genetic distances and to make indirect measures of gene flow between populations. Three of the seven RFLP loci differed significantly in allele frequencies across populations. On average, 96% of the total gene diversity was found within populations. There was little evidence for population subdivision, suggesting that gene flow was not restricted among populations. Based on an average population differentiation of 0.04, we estimated that the exchange of 11 migrants among populations per generation would be needed to account for the present level of population subdivision. Genotype diversity based on DNA fingerprints was at a maximum for the Swiss population, whereas populations in Texas and Oregon had lower genotype diversities. Many multilocus haplotypes were found in each population. Ninety-five percent of RFLP allele pairs were in gametic equilibrium. The data were consistent with random mating within each population.

Constructing reproductive histories by linking vital records

Certificates of 1,449,287 live births and fetal deaths filed in Georgia from 1980 through 1992 were linked to create chronologies that, excluding induced abortions and ectopic pregnancies, constituted the reproductive experience of individual women. The authors initially used a deterministic method (whereby linking rules were not based on probability theory) to link as many records as possible, knowing that some of the linkages would be incorrect. They subsequently used a probabilistic method (whereby evaluation of linkages was developed from probability theory) to evaluate each linkage, and they broke those that were judged to be incorrect. Of the 1.4 million records, 38% did not link to another record. From the remaining records, 369,686 chains of two or more events were constructed. The longest chain included 12 events. Of the chains, 69% included two events; 22% included three events. Longer chains tended to have lower scores for probable validity. The probability-based evaluation of chains affected 3.0% of the records that had been in chains at the end of the deterministic linkage. A greater percentage of records in longer chains were affected by the evaluation. Unfortunately, the small subset of records that were the most difficult to link tended to overrepresent groups with the greatest risk of adverse pregnancy outcomes. Researchers contemplating a similar linkage can anticipate that, for the majority of records, linkage can be accomplished with a relatively straightforward, deterministic approach.

Evaluation of reproductive histories constructed by linking vital records

We used 1.4 million fetal death and birth certificates filed in Georgia between 1980 and 1992 to construct 369,686 chains of two or more reproductive events occurring to the same woman. We evaluated these chains using both information on the certificates and information independently collected in interviews with 1311 women. Overall, 86.6% of the chains had the expected number of events, based on the certificate's information about previous pregnancies. Seventy-nine per cent of the chains had the expected number of events based on the maternal interviews. Consistency between the observed number of events in the chain and the number expected, based either on data from the certificates or from the maternal interviews, was greatest for chains with two or three events. Mothers born in Georgia were more likely to have complete chains than mothers born elsewhere. Among the 551,391 non-linked certificates, 48.7% were the mother's first birth, 40.2% were second or higher-order births to women whose previous pregnancy occurred before 1980, and 11.1% were second or higher-order births to women whose previous pregnancy occurred after 1980. Fetal death and livebirth certificates can be linked to construct pregnancy histories with reasonably low levels of underlinkage and overlinkage.

Factors associated with inadequate prenatal care during the second pregnancies among African-American women

A longitudinally linked data set for Georgia was used to identify characteristics, including previous prenatal care use and complications at the first birth, associated with prenatal care use in the second pregnancy among 8,224 African-American women. More than 70% of the women who were < 25 years of age at their first birth (younger women) and almost 40% of women who were > or = 25 years at their first birth received inadequate care with at least one of their first two births. Women who received inadequate care in their first pregnancy were more likely to receive inadequate care in their second pregnancy than women who received adequate care in their first pregnancy. Younger women with a history of a stillbirth, neonatal death, or vacuum extraction were less likely to receive inadequate care in their subsequent pregnancy. Although this study was not able to evaluate the content of prenatal care, it suggested that many African-American women may not receive sufficient care to prevent adverse pregnancy outcomes. Women who receive inadequate care in their first pregnancy must be targeted for interventions that help them overcome economic, situational, or attitudinal barriers to receiving adequate care in their next pregnancy.

The effect of placental malaria infection on perinatal mortality in rural Malawi

Perinatal deaths (fetal or infant deaths from the 28th week of pregnancy up to the seventh day after birth) occur as a result of adverse conditions during pregnancy, labor, and delivery, or in the first few days of life. Placental malaria infection is known to increase the risk of delivery of a low birth weight infant, thus, potentially increasing the risk of perinatal and infant mortality. To better understand the relationship among the adverse events in pregnancy, including placental malaria infection, adverse conditions in labor, and birth weight to perinatal mortality, we investigated the perinatal mortality among a cohort of infants born to rural Malawian women for whom placental malaria infection status and birth weight were documented. Among the 2,063 mother-singleton infant pairs, there were 111 perinatal deaths (53.8 perinatal deaths per 1,000 births). The risk of perinatal death increased as birth weight decreased. Risk factors identified for perinatal mortality among all infants excluding birth weight included abnormal delivery (cesarean section, breech, or vacuum extraction), a history of a late fetal or neonatal death in the most recent previous birth among multiparous women, reactive maternal syphilis serology, nulliparity, and low socioeconomic status. Placental malaria infection was not associated with increased perinatal mortality, but was associated with lower perinatal mortality among normal birth weight (> or = 2,500 g) infants (odds ratio = 0.35, 95% confidence interval = 0.14, 0.92). Interventions to address these risk factors could have a substantial impact on reducing perinatal mortality in this population.

Prospective assessment of mortality among a cohort of pregnant women in rural Malawi

Maternal mortality has recently received attention as a neglected public health problem in many developing countries where mortality rates are estimated to be 8-200 times those in developed countries. Most maternal mortality estimates in sub-Saharan Africa have used retrospective methods because of the lack of large population-based studies. The Mangochi Malaria Research Project, a trial of antimalarial chemoprophylaxis in pregnant women, provided an opportunity to examine prospectively mortality among the study women. Among 4,053 monitored pregnant women, 27 women were known to have died during pregnancy, labor, delivery and the one-year follow-up period. Three women died during the antenatal period and 12 died within six weeks of delivery for an estimated maternal mortality rate of 370 per 100,000 pregnant women; this rate was consistent with rates reported from retrospective surveys in Malawi. Twelve women died between three and 10 months after delivery, and the mortality rate in this nonmaternal period was estimated to be 341 per 100,000. Mortality rates in the maternal and nonmaternal periods were surprisingly similar. Human immunodeficiency virus type-1 (HIV-1) infection and anemia were strongly associated with death in the nonmaternal period. Mortality among infants of mothers who died was 3.7 times higher than the rate of death among infants born to mothers who survived. This study highlights that for rural Malawian women, pregnancy and delivery are risky periods, that the death of the mother adversely affects the survival of her children, and that HIV and anemia are important contributors to nonmaternal mortality in reproductive-age women. Strategies to reduce mortality among women of child-bearing age in sub-Saharan Africa must focus on decreasing the complications of pregnancy and delivery, and address important preventable causes of death, such as anemia and HIV infection.

Mortality associated with multiple gestation in Malawi

BACKGROUND

Multiple gestation is associated with increased maternal, perinatal, and infant mortality. The prevalence of multiple gestation varies widely with the highest rates reported among populations in Africa. There have been few population-based studies of the impact of multiple gestation on pregnancy outcomes in sub-Saharan Africa.

METHODS

Data from a 1987-1990 prospective study of the effect of malaria chemoprophylaxis among pregnant women on birthweight and mortality of their infants in a rural area of Malawi were used to estimate the prevalence of multiple gestation and to quantify the risk of mortality associated with multiple gestation compared with single gestation.

RESULTS

There were 88 (2.2%) multiple gestations among 4049 women. Mortality was high; only 38% of mothers were known to have all their infants survive to 1 year, compared with 74% in singleton gestations. The increased mortality associated with multiple gestation was due to two factors: a higher frequency of low birthweight and a fourfold increase in perinatal mortality among the infants with birthweights > or = 2500 g and among infants with unknown birthweight. We estimated that multiple gestation contributes to 5.5% of the perinatal, 1.2% of the postperinatal, and 11.5% of the maternal deaths in this population.

CONCLUSION

Multiple gestation in Malawi contributed to increased perinatal and maternal mortality, but did not increase the risk of mortality after the perinatal period.

Identification of apple cultivars using RAPD markers

Eleven apple cultivars were differentiated using randomly amplified polymorphic DNA (RAPD) markers obtained by the polymerase chain reaction (PCR). The variability of the technique and of the origin of the DNA extract was analyzed. A set of bands consistent in their presence or absence was chosen to create a differentiating band pattern. A key is proposed by which one can differentiate apple cultivars using commercially available prime.

Genetic variability for pathogenicity, isozyme, ribosomal DNA and colony color variants in populations of Rhynchosporium secalis

Samples of Rhynchosporium secalis were collected from two experimental barley populations known to carry a diverse array of alleles for resistance to this fungal pathogen. Classification of 163 isolates for four putative isozyme systems, a colony color dimorphism and 20 ribosomal DNA restriction fragment length variants revealed 49 different multilocus phenotypes (haplotypes). The six most common haplotypes differed significantly in pathogenicity. Genetic analyses of the data indicated that effective population sizes of the fungus were very large, that the effects of genetic drift were small, and that negligible recombination occurred in the populations studied. Frequency dependent selection was suggested as an explanation for the maintenance of variation in pathogenicity in the fungus.

Effects of anti-myeloid antibodies on the generation of hematopoietic colony-forming units in long-term bone marrow culture

We have prepared and characterized several monoclonal antibodies (MoAbs), PM-18 (CD 15),AML-2-23 (CD 14), and AML-1-99 (no cluster designation) reactive with antigens expressed on myeloid cells. Previous studies using complement-dependent lysis have determined the reactivity of these MoAbs with hematopoietic cells in vitro. PM-81 and AML-2-23 react with variable percentages of CFU-GM but not BFU-E or CFU-Mix. AML-1-99 reacts with greater than 90% of CFU-GM. CFU-E, and CFU-Mix. In order to determine the reactivity of these MoAbs with the bone marrow-derived precursors of in vitro colony-forming cells we have performed complement-dependent lysis and fluorescence activated cell sorting of bone marrow cells followed by long-term culture of surviving or sorted cells. Bone marrow cells from four normal subjects were subjected to various combinations of MoAbs and complement and assayed for residual colony-forming cells. Total surviving cells were then placed in flasks which contained a monolayer of irradiated bone marrow-derived adherent cells previously obtained from allogeneic donors. The cultures supported production of non-adherent colony-forming cells for up to 6 weeks as determined by serial in vitro colony-forming assays in methylcellulose. Cultures treated with one, two or three MoAbs and complement demonstrated variable reductions in colony-forming cells at the initiation of the experiments. However, cumulative production of colony-forming cells in anti-MoAb-treated cultures was usually at least as great as in control cultures.(ABSTRACT TRUNCATED AT 250 WORDS)

Coevolution of host and pathogen populations in the Hordeum vulgare-Rhynchosporium secalis pathosystem

Isolates of Rhynchosporium secalis collected from two experimental barley populations were scored for putative isozyme, colony color, and virulence loci. Allelic frequencies, multilocus haplotype frequencies, and multilocus genetic structure differed in the two populations of R. secalis; haplotypes also differed widely from each other in virulence. The average virulence of isolates collected from the more resistant host population was greater than the average virulence of the isolates collected from the less resistant host population; also the least virulent haplotype, which made up 19% of the pathogen population collected from the less resistant host population, accounted for only 0.3% of the isolates collected from the more resistant host population. It was concluded that the genetic systems of the barley host and fungal pathogen interacted in a complementary fashion and that the genetic structures of both the host and pathogen populations were shaped by coevolutionary processes featuring interactions among loci affecting many different traits, including interactions among host resistance genes and pathogen virulence genes.

Efficacy of chemoprophylaxis in preventing Plasmodium falciparum parasitaemia and placental infection in pregnant women in Malawi

73 pregnant women in Malawi were given weekly antimalarial chemoprophylaxis under observation and were monitored for Plasmodium falciparum parasitaemia and placental infection. 3 of 19 women (16%) who were parasitaemic at the time they began chemoprophylaxis were infected with chloroquine-resistant P. falciparum. After clearance of initial infections, 25% of the 73 women became parasitaemic while taking prophylaxis and 56% had evidence of active or past placental infection at the time of delivery. None of the women who were parasitaemic at the time of enrollment, and only 11% of those who had breakthrough parasitaemias while taking prophylaxis, had a history of fever and signs or symptoms that they recognized as malaria. Although the density of P. falciparum infection and rates of placental infection appeared to be lower among women taking regular chloroquine prophylaxis, this drug did not prevent P. falciparum infection among pregnant women.

Regulation of acetyl-CoA carboxylase by ADP-ribosylation

Because of certain similarities between acetyl-CoA carboxylase (ACC) and tubulin, and the recent demonstration of the ADP-ribosylation of tubulin by cholera toxin, we have investigated a potential role for ADP-ribosylation in the regulation of ACC activity. Incubation of purified rat liver ACC with cholera toxin in the presence of millimolar concentrations of [adenylate-32P]NAD results in a time-dependent incorporation of ADP-ribose into ACC of greater than 2 mol/mol of enzyme subunit, accompanied by a marked inactivation of enzyme activity. This effect is not mimicked by pertussis toxin, ADP-ribose, or ribose 5-phosphate. Incubation of labeled ACC with snake venom phosphodiesterase and alkaline hydrolysis release 32P-products tentatively identified by high-performance liquid chromatography as 5'-[32P]AMP and [32P]ADP-ribose, respectively. These data are consistent with a mono-ADP-ribosylation of ACC catalyzed by cholera toxin. Phosphodiesterase treatment of inactivated ACC partially restores enzyme activity. The effects of ADP-ribosylation of ACC are expressed both as a decrease in the enzyme Vmax and as an increase in the apparent Ka for citrate. These results suggest that ACC might be a substrate for endogenous ADP-ribosyltransferases and that this covalent modification could be an important regulatory mechanism for the modulation of fatty acid synthesis in vivo.

Phorbol esters, but not insulin, promote depletion of cytosolic protein kinase C in rat adipocytes

The tumor-promoting phorbol esters have insulinomimetic effects in several tissues. Employing two different assay systems, we have compared the effects of phorbol ester and insulin on the activity and intracellular distribution of the Ca++ and phospholipid dependent protein kinase (protein kinase C) in isolated rat adipocytes. Phorbol ester leads to a prompt depletion of kinase activity from the cytosolic fraction and appearance of activity in membrane extracts; neither of these effects is mimicked by insulin. These results, taken together with other data, emphasize important divergences between the actions of these agonists and suggest that changes in protein kinase C activity or intracellular distribution are not a necessary concomitant of the cascade of insulin action.