Contributions of preschool behavioral self-regulation and social skills to growth in different domains of early math knowledge

The current study explored the relative contribution of individual differences in children's behavioral self-regulation and social skills (often referred to as learning-related skills) in the fall of preschool to children's rate of growth in different domains of early math knowledge through the spring of kindergarten. Participants were 684 children (Mage = 57.6 months, SD = 3.8, at Time 1 [fall of preschool]; 48% female; 43% Black, 32% White, 13% Latine, 11% multiracial, and 1% Asian). All children were from families with low incomes and lived in the midwestern United States. The math domains of informal numeracy, formal numeracy, and math language were assessed at four time points: fall and spring of preschool and fall and spring of kindergarten. Contrary to expectations, we did not find that either learning-related skill positively predicted rate of growth in math knowledge or observe differential relations by math domain. Rather, the relative contribution of behavioral self-regulation and social skills in the fall of preschool to rate of growth in math knowledge followed similar patterns across all math domains: an early advantage for children with higher initial social skills that stayed consistent over time (i.e., a nonsignificant slope effect) and an early advantage for children with higher initial behavioral self-regulation that diminished over time (i.e., a negative slope effect).

International comparisons of the home mathematics environment and relations with children's mathematical achievement

BACKGROUND

Home mathematics environment (HME) research has focused on parent-child interactions surrounding numerical activities as measured by the frequency of engaging in such activities. However, HME survey questions have been developed from limited perspectives (e.g., Early Childhood Research Quarterly, 27, 2012, 231; Journal of Social Issues, 64, 2008, 95; Early childhood mathematics education research: Learning trajectories for young children, Routledge, New York, 2009), by researchers from a small subset of countries (15; Psychological Bulletin, 147, 2020, 565), which may skew our interpretations.

AIMS AND SAMPLE

This study broadened international representation by leveraging secondary data from the 2019 TIMSS to examine the variation of the frequency and reliability of the HME scale and its relation to children's mathematical achievement. Across 54 countries, 231,138 parents and children (Mage  = 10.22 years; 51% male) participated in the larger study.

METHODS

Parents completed a retrospective home environment survey and children were assessed on mathematics skills. Basic frequency descriptive statistics, Cronbach's alpha reliability coefficients, and Pearson's r correlation coefficients were used to assess variability across countries.

RESULTS

Findings suggested that families in certain countries engaged in home mathematics activities more frequently than families in other countries; however, the HME scale demonstrated acceptable internal consistency across families in all countries (M α = .79; range = [.73, .89]). Further, the average relation between HME and mathematical achievement was r = .15 with a range between r = .02 to r = .41.

CONCLUSION

Our results indicate substantial variation across countries in the HME-mathematical achievement association. These findings underscore the importance of international representation in advancing research on the diversity of a child's home environment.

Early cumulative risk and outcomes in adolescence and adulthood: The role of executive function and behavioral regulation

This study examined the extent to which early cumulative risk predicts a range of behavioral and psychological outcomes (i.e., depression, future orientation, risky behavior, educational attainment, and socioeconomic outcomes) measured at ages 15 and 26 and whether executive function (EF) and/or behavioral regulation mediated and/or moderated these associations. Data for this study came from the National Institute of Child Health and Human Development Study of Early Child Care and Youth Development and included a sample of 1,364 participants (52% male) born in 1991 and followed through age 26. Results indicated that early cumulative risk was related to depression and risky behavior at age 15 as well as depression, income, future orientation, and educational attainment at age 26. Furthermore, both EF and behavioral regulation mediated relations among cumulative risk and academic achievement at age 15 and between cumulative risk and income and educational attainment at age 26. Finally, three significant interactions emerged for age 15 outcomes, indicating that EF and behavioral regulation may change relations between cumulative risk and depression, reading, and future orientation. Implications for future research are discussed. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Corrigendum: Moving beyond dosage and adherence: a protocol for capturing dimensions of active child engagement as a measure of fidelity for social-emotional learning interventions

[This corrects the article DOI: 10.3389/fpsyg.2022.1014713.].

Factor structure of school readiness skills: conceptual vs. statistical distinctions

Introduction

School readiness skills are a broad set of abilities that children develop in early childhood that support achievement once they enter formal schooling. Three components of school readiness skills are of focus in the current study: executive function (EF), language/literacy, and mathematics. The current study examines to what extent 13 direct assessments of these skills statistically align with theoretical models for distinct construct- and timepoint-specific latent factors.

Methods

The sample included 684 children (52.34% male; 42% Black/African American; M_age = 4.80 years in the fall of prekindergarten) assessed in the fall and spring of the prekindergarten year.

Results

Factor analyses revealed the most statistical support for a model with a latent random intercept across timepoints and constructs, along with timepoint-specific latent factors in the fall and spring of prekindergarten (independent of the random intercept). The timepoint-specific latent factors primarily consisted of early literacy and mathematics assessments.

Discussion

These findings challenge commonly held practices of creating construct-specific latent factors in early childhood research and, to a lesser extent, timepoint-specific latent factors without consideration of the substantial shared variance across different constructs and timepoints. Implications for the factor structure and developmental theory of school readiness skills are considered, as well as practical considerations for future research.

The home numeracy environment and children's math skills: The moderating role of parents' math anxiety

Evidence suggests that parents' math anxiety moderates the association between parents' help in mathematics homework and first graders' mathematics skills. Understanding whether similar associations are evident in younger children, in regard to the home numeracy environment (HNE) is essential, given that early math skills are strong predictors of later academic outcomes, and children's skills prior to kindergarten are fostered principally by their parents. Thus, the purpose of this study was to examine the association and interaction between the HNE and parents' math anxiety related to preschool children's numeracy performance. Participants were 121 parent-child dyads. Results from hierarchical multiple regression models demonstrated that parents' math anxiety and the HNE, included as separate predictors of children's math skills, were not statistically significant. However, the interaction between HNE and parents' math anxiety was statistically significant, such that the positive association between HNE and children's numeracy skills emerged when parents felt less anxious about math. These findings highlight the importance of accounting for parents' math anxiety when exploring the home influences on children's numeracy skills.

Parent and child adjustment dual trajectories at the beginning of the COVID-19 syndemic

Children and their families have been significantly impacted by the unfolding of the COVID-19 syndemic. We sought to identify (1) groups of families with distinct profiles of joint trajectories of parental anxiety and child emotional distress and (2) protective and risk factors associated with these dual-trajectory profiles. A sample of 488 parents (65% White; 77% mothers) with 3- to 8-year-old children (M_Age  = 5.04, SD_Age  = 1.59) was followed from late March to early July in 2020. Survey data on parent (i.e., anxiety symptoms) and child (i.e., emotional distress) adjustment were collected at three time points. Using multivariate growth mixture modeling, we identified one group with low parental anxiety and child emotional distress (42.7%) and three other distinct groups with varying risk levels among parents and/or children. We also identified protective (e.g., positive parenting) and risk (e.g., child negative affect, negative parenting, perceived stress with racism) factors in predicting parent and child adjustment. It can be concluded that, overall, our sample (mostly middle- and high-socioeconomic status families) demonstrated family resilience amid COVID-19, consistent with prior disaster coping literature. At the same time, our findings also indicated the need to identify at-risk families and modifiable factors for post-disaster public health interventions.

Moving beyond dosage and adherence: A protocol for capturing dimensions of active child engagement as a measure of fidelity for social-emotional learning interventions

Social-emotional competencies are important for school-readiness and can be supported through social-emotional learning (SEL) interventions in the preschool years. However, past research has demonstrated mixed efficacy of early SEL interventions across varied samples, highlighting a need to unpack the black box of which early interventions work, under what conditions, and for whom. In the present article we discuss the critical implementation component of active child engagement in an intervention as a potential point of disconnect between the intervention as designed and as implemented. Children who are physically present but unengaged during an intervention may lead to decreased average impacts of an intervention. Furthermore, measuring young children's active engagement with an intervention may help to guide iterative intervention development. We propose a four-step protocol for capturing the multi-dimensional and varied construct of active child engagement in a SEL intervention. To illustrate the utility of the protocol, we apply it to data from a pilot study of a researcher-implemented, semi-structured block play intervention focused on supporting the development of SEL and math skills in preschoolers. We then present future directions for the integration of active participant engagement into the measurement of implementation of SEL interventions for young children.

Bi-directional relations between behavioral problems and executive function: Assessing the longitudinal development of self-regulation

During childhood, the ability to limit problem behaviors (i.e., externalizing) and the capacity for cognitive regulation (i.e., executive function) are often understood to develop in tandem, and together constitute two major components of self-regulation research. The current study examines bi-directional relations between behavioral problems and executive function over the course of childhood and adolescence. Relying on a diverse sample of children growing up in low-income neighborhoods, we applied a random intercept cross-lagged panel model to longitudinally test associations between behavioral problems and executive function from age 4 through age 16. With this approach, which disaggregated between- and within-child variation, we did not observe significant cross-lagged paths, suggesting that within-child development in one domain did not strongly relate to development in the other. We also observed a relatively moderate correlation between the stable between-child components of behavioral problems and executive function over time in our preferred model, suggesting that these two domains may be relatively distinct when modeled from early childhood through adolescence. We tested associations between behavioral problems and executive function among children from low-income families, using a random intercept cross-lagged panel model. Our results demonstrated that bi-directional effects at the within-child level between behavioral problems and executive function were consistently small and non-significant over the course of childhood and adolescence. To the extent that behavioral problems and executive function were related to one another, this relation only appeared at the between-child level. Our results imply that behavioral problems and executive function may not be as developmentally intertwined as previous theory suggests. This article is protected by copyright. All rights reserved.

Prenatal programming of developmental trajectories for obesity risk and early pubertal timing

The thrifty phenotype and fetal overnutrition hypotheses are two developmental hypotheses that originated from the developmental origins of health and disease (DOHaD) perspective. The DOHaD posits that exposures experienced prenatally and early in life may influence health outcomes through altering form and function of internal organs related to metabolic processes. Obesity risk and early pubertal timing might be influenced by similar mechanisms. The thrifty phenotype hypothesis is primarily characterized by experiencing a deprivation of nutrients during gestation paired with an energy rich postnatal environment. The fetal overnutrition hypothesis says that obesity experienced prenatally will be associated with increased lifetime risk of obesity in the offspring. Both hypotheses were tested by examining developmental pathways from genetic and prenatal risk through early growth trajectories (birth to 7 years) to pubertal timing at age 11 years. Participants included 361 children adopted at birth (57% male; 57% non-Hispanic White, 11% Black, 9% Hispanic; adoptive family income Mdn = $70,000-$100,000, birth family income Mdn = < $15,000). Associations between boys' childhood body mass index (BMI) and pubertal timing were confounded by genetics, prenatal risk, and early growth. The thrifty phenotype hypothesis was partially supported for boys' childhood BMI (at ages 4 to 7 years). Both hypotheses were partially supported for girls' childhood BMI but not pubertal timing. A novel Gene × Prenatal Risk interaction showed that genetic risk predicted girls' childhood BMI most strongly at adequate compared with at excessive levels of gestational weight gain. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

Examining longitudinal associations between internalizing problems, body mass index, and language during childhood

The current study examines the extent to which associations between internalizing problems, body mass index (BMI), and language skills from early (36 months) to late childhood (fifth grade) are due to relatively stable between-child differences, time-specific correlations, or cross-lagged paths. Data from the NICHD study, Early Child Care and Youth Development (N = 1,364) were used. Results showed that internalizing problems and language are significantly and negatively correlated due to relatively stable between-child differences, with some evidence of positive cross-lagged paths, where better language at 36 months, 54 months, and third grade predicted more internalizing problems at the subsequent timepoint, and more internalizing problems at third grade predicted better language at fifth grade. Time-specific associations for BMI showed a negative correlation with language at 36 months and a positive correlation with internalizing problems at 54 months only. Additionally, higher internalizing at third grade predicted higher BMI at fifth grade, though the association was small and no other cross-lagged paths between internalizing and BMI emerged. These findings suggest that previous research documenting cross-lagged associations between BMI and internalizing problems, and between language and internalizing problems may be biased due to between child differences not fully controlled for in prior models. Implications for understanding these key aspects of youth's healthy development are considered. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

Examining Associations Between Food Insecurity, Inhibitory Control, and Body Mass Index in Preschoolers

OBJECTIVE

This study examines relations between food insecurity, inhibitory control, and body mass index (BMI) in early childhood.

METHOD

The sample comes from an evaluation of a state-funded prekindergarten program and includes 126 children (mean age = 4.73 yrs, female = 42%) from families with low incomes. Parents reported on their child's food insecurity. Child inhibitory control was assessed using a performance-based task, and children's height and weight were objectively collected at the same time as the inhibitory control assessment. A regression model was used to test whether inhibitory control moderated the association between food insecurity and BMI. The model included a large battery of covariates and adjusted for clustering at the classroom level. Ad hoc analyses were conducted to examine the robustness of findings to different conceptualizations of food insecurity based on the US Department of Agriculture's categories for severity.

RESULTS

A significant interaction revealed that inhibitory control moderated the association between food insecurity and children's BMI percentile. Investigation of the simple slopes suggested that greater food insecurity was related to a higher BMI percentile among children who demonstrated stronger inhibitory control. In addition, results from ad hoc analyses examining categories of food insecurity indicated that experiencing very low food security was also related to a higher BMI among children with average and strong inhibitory control.

CONCLUSION

This study makes a unique contribution to the existing literature by examining relations among food insecurity, inhibitory control, and BMI during a critical period in children's physical and brain development. Findings have implications for public health efforts to address childhood obesity among populations with low incomes.

Examining transactional relations between behavioral self-regulation and social-emotional functioning during the transition to kindergarten

The present study examined longitudinal associations between behavioral self-regulation and social-emotional functioning across four waves of measurement during the transition from preschool to kindergarten in a low-income sample. Participants included two cohorts of children (N = 558; 51% male). Children in both cohorts were 4 years old (Cohort 1: M = 4.82 years, SD = .31; Cohort 2: M = 4.80 years, SD = .31). Forty-four percent of children were Black, 32% were White, 13% were Latino, 10% were Multiracial, and 1% were Asian. Monthly income ranged from $0-5,539 (M = $1,508.18, SD = $892.92). Two statistical methods were used to examine relations among constructs. The cross-lagged panel model revealed a mixed pattern of relations between behavioral self-regulation and two indicators of social-emotional functioning (social skills and behavior problems) over time. There were no significant relations among behavioral self-regulation and social-emotional functioning during the preschool year; however, evidence for bidirectional associations were found between the spring of preschool and the fall of kindergarten. There were no significant relations among behavioral self-regulation and behavior problems at any time point. Finally, there were bidirectional relations among social skills and behavior problems in preschool, but directional relations emerged after this time point. A second model that included random intercepts was also run with the cross-lagged paths. Results from this model indicated that the random intercepts between behavioral self-regulation, social skills, and behavior problems were significantly related. Implications for future research are discussed. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

Examining Additive and Synergistic Relations Between Preschool Self-Regulation and Executive Function Skills: Predictions to Academic Outcomes

In the present study, we examined the extent to which teacher-rated self-regulation and directly assessed executive function skills were independently, additively, or synergistically related to academic achievement during the transition to kindergarten. The sample included 126 children (42% female; M_age = 4.73 years) from families with low incomes who participated in a larger evaluation of state-funded preschool. Regression models with children nested in their respective preschool classrooms investigated main effects and moderated effects of teacher-rated self-regulation skills manifested in preschool classroom behaviors and cognitive executive function skills assessed through direct assessments on math, literacy, and vocabulary in the spring of preschool and in the fall of kindergarten. Results revealed independent but not additive relations between executive function and math in the spring of preschool and self-regulation and literacy in the fall of kindergarten. One significant interaction emerged providing evidence for synergistic relations between teacher-rated self-regulation and directly assessed executive function for literacy at both timepoints across the transition to kindergarten. Implications for policy and practice are discussed.

Parents' math anxiety and mathematics performance of pre-kindergarten children

Prior research demonstrates that individuals' math anxiety may be negatively related to their mathematics performance. However, little research has examined how caregivers' math anxiety is associated with children's mathematics performance prior to kindergarten. The purpose of this study was to investigate the relation between parents' math anxiety and the change in children's mathematics performance during the preschool year. Participants were 310 preschool-age children (155 female; 4.12-5.78 years of age, M = 5.20 years, SD = 0.29). Structural equation modeling results demonstrated that parents' math anxiety was significantly negatively related to change in children's mathematics performance during the pre-kindergarten year when controlling for fall mathematics performance and demographics. Moreover, multigroup path analyses revealed that this association did not differ for male versus female children.

Childhood Protective Factors and a Prevention Program Reduce Later Problem Behaviors

Prior research has yet to elucidate how constellations of protective factors in childhood and prevention efforts simultaneously may influence youth involvement in problem behaviors across different points in development. The current study examines how latent classes of social and emotional learning (SEL) skills, parent-child relationships, and peer influences in third grade and receipt of an ongoing SEL intervention predict substance use and violence in fifth and eighth grade. The urban, predominantly low-income, sample (N = 1,169) was nested in 14 schools that were randomly assigned to the Positive Action program or business-as-usual. Membership in a latent class reflecting protective childhood factors predicted less substance use and violence in fifth grade; however, the SEL program predicted less substance use and violence in eighth grade. Findings generally support that SEL interventions can successfully target and boost developmentally appropriate positive behaviors and can prevail over initial risk factors with enough time and exposure.

Construct-Specific and Timing-Specific Aspects of the Home Environment for Children's School Readiness

Prior evidence supports that the home environment is related to children’s development of school readiness skills. However, it remains unclear how construct- and timing-specific aspects of the home environment are related to children’s school readiness skills, unique from overall, stable aspects of home quality. Unpacking associations due to specific constructs and timing of the home environment may provide insights on the theoretical processes that connect the home environment to school readiness. Using data from the NICHD Study of Early Child Care and Youth Development (N = 1,364), the current study examines how timing (36 and 54 months) and constructs (educational stimulation and socio-emotional responsivity) of the home environment, relative to overall levels across time, relate to children’s language skills, math skills, and externalizing behaviors. The overall, stable aspects of the home environment were significantly associated with children’s language skills and externalizing problems. Additionally, there were significant paths from the stimulation construct at 54 months to math skills, language skills, and externalizing problems. These findings provide evidence that although the overall home environment is predictive of school readiness, the stimulation construct of the home environment at 54 months has additional concurrent relations to children’s school readiness. Implications for the role of the home environment and children’s school readiness are discussed.

The Kindergarten Early Development Instrument Predicts Third Grade Academic Proficiency

School readiness skills predict later educational achievement, health, and social-emotional outcomes. Measures of school readiness can provide valuable information to assess both the impact of strategies and policies that prepare children for school as well as informing strategies for improving children's educational trajectories across their school years. The Early Development Instrument (EDI) is a measure of school readiness skills based on teacher-reported observational recall. It has been used extensively in Canada and Australia and is in the early stages of adoption in a number of U.S. cities. The current study uses data from roughly 3,000 children followed longitudinally from kindergarten through third grade from 7 school districts in Orange County, California. The study assesses whether EDI ratings in kindergarten predict third grade proficiency in mathematics and English Language Arts on state assessments. Ratings on the EDI were strongly associated with proficiency in both academic areas, even in the presence of controls for child-level factors and neighborhood fixed effects. Among its components, ratings on the language and cognitive development, communication skills and general knowledge, and social competence domains strongly differentiated children's likelihood of later proficiency in both academic areas. Implications for improving comprehensive early childhood education and schooling policies based on indicators of school readiness are discussed.

Additive and synergistic relations of early mother-child and caregiver-child interactions for predicting later achievement

This study examines associations between stimulating-responsive social interactions with mothers and nonparental childcare providers during the first 3 years of life and children's vocabulary and mathematics skills through age 15 (N = 1,364). Additive relations were found in which more stimulating-responsive interactions with mothers and with caregivers were linked to higher mathematics achievement in childhood and adolescence. More stimulating-responsive early interactions with mothers were also associated with larger child vocabularies through age 15. Synergistic relations, consistent with the dual-risk hypothesis, also were found. Children whose early interactions with both mothers and caregivers were low in stimulation and responsivity had substantially lower mathematics skills. Implications for early childhood interventions and policies are discussed. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

Theoretical and Methodological Implications of Associations between Executive Function and Mathematics in Early Childhood

Despite agreement about the importance of executive function (EF) for children's early math achievement, its treatment in correlational studies reflects a lack of agreement about the theoretical connection between the two. It remains unclear whether the association between EF and math operates through a latent EF construct or specific EF components. Specifying the correct measurement model has important theoretical implications for the predicted effects of EF interventions on children's math achievement. In the current study, we tested whether associations between EF and math operate via a latent EF factor, or via specific EF components using data from a large, nationally representative sample. We then replicated these same analyses with a meta-analytic database drawn from ten studies that collected measures of children's EF and math achievement. Our results lend support to explanations that a single EF factor accounts for most of the EF component-specific associations with math achievement. We discuss theoretical and methodological implications of these findings for future work.

Longitudinal Associations of Sleep Duration, Morning and Evening Cortisol, and BMI During Childhood

OBJECTIVE

This study aimed to examine associations between sleep duration, BMI, and cortisol levels across childhood.

METHODS

Participants included 361 children adopted domestically in the United States. Random-intercept cross-lagged panel models tested for between-person and bidirectional within-person associations of sleep duration, BMI, and morning and evening cortisol at age 4.5 to 9 years.

RESULTS

Sleep duration and BMI were stable during childhood, inversely associated at the between-person level, and unrelated to morning or evening cortisol. BMI at age 6 years predicted longer sleep duration and lower evening cortisol at age 7 years, and lower morning cortisol at age 7 years predicted higher BMI at age 9 years within individuals.

CONCLUSIONS

The association between sleep and BMI is more likely a stable between-person phenomenon rather than a unidirectional association that develops within individuals over time.

Combining a Kindergarten Readiness Summer Program with a Self-Regulation Intervention Improves School Readiness

Self-regulation and academic skills in kindergarten are strong predictors of later achievement. However, many children enter kindergarten without adequate levels of these skills, often because of limited participation in early childhood education. The current study examined a kindergarten readiness summer program (Bridge to Kindergarten; B2K) that served children with no prior preschool experience. The first study goal was to examine the effects of adding a self-regulation intervention to the B2K program on children's self-regulation, math, and literacy. The second study goal was to compare changes in self-regulation, math, and literacy during the kindergarten transition period for children attending the B2K program with the intervention to expected development. Results from a randomized trial indicated that children who participated in the B2K program that included the self-regulation intervention experienced more gains in self-regulation relative to children who participated in the B2K program alone. There were no significant effects on math or literacy at the end of the program. However, when examining change during the kindergarten transition period, participation in the B2K program with the self-regulation intervention was associated with improved growth in self-regulation, math, and literacy into the fall of kindergarten compared to expected development. Collectively, the findings suggest a kindergarten readiness summer program that incorporates a self-regulation intervention leads to improved school readiness in children at higher risk for later school difficulties.

Effects of dietary phosphorus and protein in dogs with chronic renal failure

Four diets were formulated to contain: 16% protein and 0.4% phosphorus--diet 1; 16% protein and 1.4% phosphorus--diet 2; 32% protein and 0.4% phosphorus--diet 3; and 32% protein and 1.4% phosphorus--diet 4. Forty-eight dogs were fed diet 1 for 3 months after surgical reduction of renal mass, then were allotted to 4 groups of 12 dogs each, with equal mean values for glomerular filtration rate (GFR). Dog of groups 1-4 were fed diets 1-4, respectively, for 24 months. Data collected from the dogs during and at termination of the study were analyzed statistically for effects of dietary protein, phosphorus (P), time, and interactions between these factors. During the 24 months of study, 24 dogs developed uremia and were euthanatized for necropsy. Necropsy also was performed on the remaining 24 dogs after they were euthanatized at the end of the study. Dog survival was significantly enhanced by 0.4% P diets (vs 1.4% P diets), but survival was not significantly influenced by amount of dietary protein. The 0.4% P diets (vs 1.4% P diets) significantly increased the period that GFR remained stable before it decreased, but dietary protein did not have significant effect. Significant blood biochemical changes attributed to P, protein, and time were identified during the study. Terminally, plasma parathyroid hormone concentration was significantly increased from prediet values in all groups of dogs. Urine protein excretion was not significantly affected by dietary amount of either protein or P, when measured by either timed urine collection or urine protein-to-creatinine ratio.(ABSTRACT TRUNCATED AT 250 WORDS)

Preliminary report: accurate assays for anti-HIV in urine

Untreated urine specimens from 358 patients (344 attending genito-urinary medicine clinics, 14 haemophiliacs) and 353 blood donors were tested blind by a simple IgG-capture particle-adherence test (GACPAT) and a rapid IgG-capture enzyme-linked immunosorbent assay (GACELISA) for antibody to human immunodeficiency virus (anti-HIV). All 158 urine specimens from seropositive subjects were anti-HIV positive by GACPAT and 157 of them (99.4%) were positive by GACELISA. Tests on 553 urine specimens from seronegative subjects gave two repeatable false-positive reactions by GACPAT (0.4%) and none by GACELISA. By means of a modified procedure anti-gp160 was detected by commercial western blot in the urine of 44 of 45 seropositive subjects examined. IgG-capture assays will detect anti-HIV in unconcentrated urine and so allow a diagnosis in circumstances when blood sampling is impracticable.

Changes in insulin receptor expression in HL60 cells induced to differentiate towards neutrophils or monocytes

HL60 is a human promyeloid cell line capable of differentiating towards monocytes or granulocytes when treated with appropriate agents. Changes in insulin receptor number, affinity and mRNA levels were observed when HL60 cells were induced to differentiate with 12-O-tetradecanoyl-phorbol-13-acetate (TPA) or dimethylsulphoxide (DMSO). Total and high-affinity insulin receptor numbers decreased following treatment of HL60 cells with DMSO, whereas total insulin receptor number increased and high-affinity receptor number decreased in cells treated with TPA. Three distinct insulin receptor mRNA species of 9.1, 6.3 and 2.8 kb were identified in HL60 cells. The larger 9.1 and 6.3 kb species were increased in both TPA- and DMSO-treated HL60 cells, and the 2.8 kb mRNA was reduced in differentiated cells. Thus HL60 cells differentiated towards monocytes or granulocytes showed similar changes in the levels of individual insulin receptor mRNAs, but displayed contrasting alterations in low-affinity insulin binding. Three HL60 variant lines, which have different capacities to respond to inducers of monocyte and neutrophil differentiation, showed similar levels of total insulin receptors, but differed in their expression of high-affinity receptors. The data provide evidence for the existence of two distinct insulin receptors.

Aldehyde dehydrogenase. An enzyme with two distinct catalytic activities at a single type of active site

The evidence for and against the esterase and dehydrogenase active sites of aldehyde dehydrogenase being topologically distinct is examined. It is found that all the evidence (including all that previously amassed by others in favour of distinct binding domains) is actually consistent with, and in favour of, a single type of catalytic site having both activities. The existence of separate high-Km modulating sites for the enzyme is also questioned.

A new reagent which may be used to introduce sulfhydryl groups into proteins, and its use in the preparation of conjugates for immunoassay

A synthesis of the N-hydroxysuccinimide ester of S-acetylthioacetic acid is described. This material is stable when stored dry and has advantages over the currently available reagents used to introduce sulfhydryl groups into a variety of proteins. Proteins modified with this reagent can be used to prepare conjugates for enzyme immunoassay. The conjugation techniques described cause little or no loss of either enzyme activity or antibody titer and function, and the conjugates contain little polymeric material.

Activation of beta-galactosidase by monoclonal antibodies

Four monoclonal cell lines secreting antibodies that activate the beta-galactosidase protein from lac-aba strains of Escherichia coli have been isolated. One of the antibodies, BG 79, inhibits the normal beta-galactosidase from E. coli in addition to its activation of the protein from mutants. Moreover, when in combination with any of the other activating antibodies, BG 79 exhibits synergistic activation of the beta-galactosidase protein, and the synergistically activated enzyme is stimulated by methanol, although most of the proteins activated by single antibodies are inhibited by methanol. The equilibrium of binding of BG 79 to the beta-galactosidase protein is not affected by the presence of a second antibody, and the half-time for activation by BG 79 is only slightly, though significantly, increased by preincubation of the protein with the second antibody. Our results imply that activation of beta-galactosidase proteins is not a simple correction of a conformational defect, and that many distinct active conformations are available to the enzyme.

Reversal of part of the aldehyde dehydrogenase reaction pathway during the hydrolysis of an ester

An aldehyde dehydrogenase from rabbit liver, a homogeneous protein on three distinct polyacrylamide-gel systems, has an associated 4-nitrophenyl esterase activity. At pH 7.0 in the presence of 80 micrometer-NADH and 800 micrometer-4-nitrophenyl acetate the enzyme produces NAD+ and a stoicheiometric amount of an aldehyde, as well as hydrolysing the ester. On this and other evidence it is proposed that ester hydrolysis occurs at the usual active site of the enzyme.

Identiy of brain alcohol dehydrogenase with liver alcohol dehydrogenase

A method for obtaining electrophoretically homogeneous rat liver alcohol dehydrogenase (EC 1.1.1.1) at a specific activity of 2-2.5 mumol/min per mg of protein is presented. Anti-sera prepared against the purified enzyme inhibit alcohol dehydrogenase by up to 75% and cause precipitation of virtually all the enzyme. The antisera were shown by immunoelectrophoresis of a partially purified liver homogenate to be specifically directed against alcohol dehydrogenase and were used to demonstrate that the alcohol dehydrogenases of rat brain and liver share common antigens. The total activity of alcohol dehydrogenase in rat brain homogenates is normally quite low, with as much as 10% of the total activity attributable to the activity in the blood contained within the brain; in cases of severe liver damage (induced experimentally with carbon tetrachloride) this contribution may rise to as much as 60%.

Effects of asphyxia and potassium on canine and feline electrocardiograms

The effects of asphyxia and potassium on the electrocardiogram (ECG), lead II, were recorded from dogs and cats anesthetized with sodium pentobarbital and halothane. Electrocardiographic recordings were made during control periods, during asphyxia (occluded endotracheal tube), during infusion of an isotonic KCl solution and during infusion of an isotonic NaCl solution. Arterial and venous blood gas partial pressures (PaCO2, PvCO2, PaO2 and and PvO2), plasma Na+ and K+ concentrations, heart rate and mean arterial blood pressure were measured during control periods, asphyxia and during the periods of infusion. The vagi were severed to assess the effect of vagal tone on the ECG changes. The characteristic ECG changes during asphyxia and the electrolyte imbalances resulting from infusion of isotonic KCl and NaCl were determined during sodium pentobarbital and halothane anesthesia in both dogs and cats. The combination of halothane and high PCO2 caused cardiac arrhythmias. Spontaneous recovery from ventricular fibrillation, as a result of hyperkalemia, was recorded from cats. Disappearance of the P waves, which is characteristic of hyperkalemia, was infrequent in this study and the U waves associated with hypokalemia were not found. Severing the vagi did not alter the ECG changes characteristic of asphyxia, hyperkalemia and hypokalemia. It was found that asphyxia and infusion of fluids high or low in potassium can produce ECG changes in both dogs and cats that can be correlated with blood gas partial pressure changes or plasma potassium concentrations.