Joel Ager

A socially contextualized model of African American identity: Possible selves and school persistence.

Schooling, critical to the transition to adulthood, is particularly problematic for urban and minority youths. To explore predictors of school persistence the authors propose a socially contextualized model of the self. Strategies to attain achievement-related possible selves were differentially predicted for White and Black university students (Study I, n = 105). For Whites, individualism, the Protestant work ethic, and balance in possible selves predicted generation of more achievement-related strategies. For Blacks, collectivism, ethnic identity, and low endorsement of individualism tended to predict strategy generation. In middle school, performance was predicted by gendered African American identity schema, particularly for females (Study 2, n = 146), and the effects of social context appeared gendered (Study 3, n = 55). Balance in achievement-related possible selves predicted school achievement, especially for African American males ( Study 4, n = 55).

Role of chronic hyperglycemia in the pathogenesis of coronary microvascular dysfunction in diabetes.

OBJECTIVES We sought to determine the differences in coronary microvascular function between patients with type 1 (insulin-deficient) and type 2 (insulin-resistant) diabetes mellitus (DM). BACKGROUND Coronary vascular function is impaired in patients with DM. However, it is unclear whether the type and/or severity of this vascular dysfunction are similar in patients with type 1 and type 2 DM. METHODS We studied 35 young subjects with DM (18 with type 1 and 17 with type 2), who were free of overt cardiovascular complications, and 11 age-matched healthy controls. Positron emission tomography imaging was used to measure myocardial blood flow (MBF) at rest, during adenosine-induced hyperemia (reflecting primarily endothelium-independent vasodilation), and in response to cold pressor test (CPT) (reflecting primarily endothelium-dependent vasodilation). RESULTS The two groups of diabetics were similar with respect to age and glycemic control. The duration of diabetes was longer and high-density lipoprotein cholesterol levels were higher in type 1 than in type 2 diabetics. Basal MBF was similar in the three groups studied. The increase (from baseline) in MBF with adenosine was similar in the subjects with type 1 (161 +/- 18%) and type 2 (185 +/- 19%) DM, but lower than in the controls (351 +/- 43%) (p < 0.001 for the comparison with both groups of diabetics). Similarly, the increase in MBF during the CPT was comparable in the subjects with type 1 (23 +/- 4%) and type 2 (19 +/- 3%) DM, but lower compared with the controls (66 +/- 12%) (p < 0.0001 for the comparison with both groups of diabetics). These differences persisted after adjusting for the duration of diabetes, insulin treatment, metabolic abnormalities, and autonomic neuropathy. CONCLUSIONS These results demonstrate markedly reduced and similar endothelium-dependent and -independent coronary vasodilator function in subjects with both type 1 and type 2 DM. These results suggest a key role of chronic hyperglycemia in the pathogenesis of vascular dysfunction in diabetes.

Alcohol teratogenicity in the human: A detailed assessment of specificity, critical period, and threshold

Though the occurrence of alcohol-related birth defects is well documented in the human and in animal models, definition of specificity, critical period, and dose-response threshold with a precision adequate for clinical risk assessment and management has been lacking. Data from a cohort of 359 neonates, from a large prospective observational study in which chronic alcohol problems and maternal drinking were assessed during pregnancy and standardized neonatal examinations were blinded for prenatal information, were analyzed with the use of multivariate techniques, with uniform control for confounding by eight factors. Craniofacial abnormalities were found to be definitively related to prenatal alcohol exposure in a dose-response manner (p less than 0.001); a significant, but less striking, relationship was observed for other anomalies (p less than 0.01). The critical period for alcohol teratogenicity was confirmed to be around the time of conception. Risk for anatomic abnormalities in the offspring was clearly defined among the 5.6% of infants whose mothers drank more than three ounces of absolute alcohol, that is, more than six drinks, per day. Because of a trend toward an increase in craniofacial abnormalities with increasing embryonic alcohol exposure at lower levels, a clear threshold could not be defined. These are not experimental data and the results should not be overinterpreted. Nevertheless, pending further studies with larger samples, the findings suggest that to completely avoid alcohol-related anatomic abnormalities, advice to discontinue drinking or at least to reduce it to a minimal level before conception is clinically appropriate.

Alterations in Frontal Lobe Tracts and Corpus Callosum in Young Children with Autism Spectrum Disorder

Major frontal lobe tracts and corpus callosum (CC) were investigated in 32 children with autism spectrum disorder (ASD, mean age: 5 years), 12 nonautistic developmentally impaired children (DI, mean age: 4.6 years), and 16 typically developing children (TD, mean age: 5.5 years) using diffusion tensor imaging tractography and tract-based spatial statistics. Various diffusion and geometric properties were calculated for uncinate fasciculus (UF), inferior fronto-occipital fasciculus (IFO), arcuate fasciculus (AF), cingulum (Cg), CC, and corticospinal tract. Fractional anisotropy was lower in the right UF, right Cg and CC in ASD and DI children; in right AF in ASD children; and in bilateral IFO in DI children, compared with TD children. Apparent diffusion coefficient was increased in right AF in both ASD and DI children. The ASD group showed shorter length of left UF and increased length, volume, and density of right UF; increased length and density of CC; and higher density of left Cg, compared with the TD group. Compared with DI group, ASD group had increased length, volume, and density of right UF; higher volume of left UF; and increased length of right AF and CC. Volume of bilateral UF and right AF and fiber density of left UF were positively associated with autistic features.

Maternal recall of alcohol, cocaine, and marijuana use during pregnancy

Alcohol, cocaine, and marijuana use during pregnancy was reported antenatally and at 13 months postpartum by 361 black inner city mothers. The two reports were moderately related for all three substances, but levels reported retrospectively were substantially higher. MAST scores did not differ for the two interviews. Most of the correlations of the antenatal and retrospective reports with maternal and infant characteristics were similar in magnitude; those that differed were somewhat stronger for the antenatal measures. Although the retrospective reports may provide a better indication of mean levels of fetal exposure, they may be less precise in rank ordering among individuals for purposes of correlational analysis. Women with higher MAST scores were particularly prone to report higher levels of both alcohol and cocaine when interviewed retrospectively, and more severely depressed mothers were more likely to report higher levels retrospectively for all three substances. These data suggest that women reporting more than 1.3 drinks/week antenatally (AA/day greater than 0.1) may actually be drinking at levels at risk for alcohol-related birth defects.

Effects of alcohol use, smoking, and illicit drug use on fetal growth in black infants.

STUDY OBJECTIVES To compare the effects of prenatal exposure to alcohol, smoking, and illicit drugs on birth size. DESIGN Prospective, longitudinal correlational study, with statistical control for confounding. PARTICIPANTS Four hundred seventeen black infants. Mothers recruited at first prenatal clinic visit on the basis of moderate-to-heavy use of alcohol or cocaine or both, plus a 5% random sample of lower-level drinkers and abstainers. MAIN RESULTS Alcohol, smoking, opiates, and cocaine were each correlated with smaller birth weight, length, and head circumference (median r = -0.21; p < 0.001). However, when all four substances, gestational age, and six covariates were controlled statistically, birth weight related only to alcohol and smoking (p < 0.05), length only to alcohol (p < 0.05), and head circumference only to opiates (p < 0.01). Although smoking affected birth weight at all levels of exposure, a larger deficit was seen in relation to heavy drinking (509 gm) than to heavy smoking (269 gm). Alcohol and smoking did not affect birth size synergistically, and their effects were seen primarily in infants of women more than 30 years of age. CONCLUSIONS The association of reduced birth weight and length with illicit drug use may be a consequence of simultaneous exposure of the fetus to alcohol and smoking. Opiate exposure is specifically related to reduced head circumference, and the effect of cocaine on birth size is primarily an indirect consequence of shorter gestation and poorer maternal nutrition.

Multimodality imaging for improved detection of epileptogenic foci in tuberous sclerosis complex

Objective: Using interictal α-[11C]methyl-l-tryptophan ([11C]AMT) PET scan, the authors have undertaken a quantitative analysis of all tubers visible on MRI or 2-deoxy-2-[18F]fluoro-d-glucose ([18F]FDG) PET, to determine the relationship between [11C]AMT uptake and epileptic activity on EEG. Background: Tuberous sclerosis complex (TSC) is an autosomal dominant disorder, often associated with cortical tubers and intractable epilepsy. The authors have shown previously that [11C]AMT PET scans show high tracer uptake in some epileptogenic tubers and low uptake in the remaining tubers. Methods: Eighteen children, age 7 months to 16 years, were studied. Patients underwent video-EEG monitoring, PET scans of [11C]AMT and [18F]FDG, and T2-weighted or fluid-attenuated inversion recovery (FLAIR) MRI. [11C]AMT uptake values were measured in 258 cortical tubers delineated with coregistered MRI or [18F]FDG scans. Uptake ratios were calculated between the [11C]AMT uptake in tubers and those for normal cortex (tuber/normal cortex). Using the region of epileptiform activity, the authors performed receiver operator characteristics (ROC) analysis and determined the optimal uptake ratio for detecting presumed epileptogenic tubers. Results: Tuber uptake ratios ranged from 0.6 to 2.0. Tuber uptake ratios in the epileptic lobes were higher than those in the nonepileptic lobes (p < 0.0001). All 15 patients with focal seizure activity showed one or more lesions with uptake ratio above 0.98 in the epileptic lobe. ROC analysis showed that a tuber uptake ratio of 0.98 resulted in a specificity of 0.91. Conclusions: Cortical tubers with [11C]AMT uptake greater than or equal to normal cortex are significantly related to epileptiform activity in that lobe. Together, interictal [11C]AMT PET and FLAIR MRI improve the detection of potentially epileptogenic tubers in patients with TSC being evaluated for epilepsy surgery.

Teacher-Assessed Behavior of Children Prenatally Exposed to Cocaine

Objective. Prenatal cocaine exposure has been associated with alterations in neonatal behavior and more recently a dose–response relationship has been identified. However, few data are available to address the long-term behavioral effects of prenatal exposures in humans. The specific aim of this report is to evaluate the school-age behavior of children prenatally exposed to cocaine. Methods. All black non–human immunodeficiency virus–positive participants in a larger pregnancy outcomes study who delivered singleton live born infants between September 1, 1989 and August 31, 1991 were eligible for study participation. Staff members of the larger study extensively screened study participants during pregnancy for cocaine, alcohol, cigarettes, and other illicit drugs. Prenatal drug exposure was defined by maternal history elicited by structured interviews with maternal and infant drug testing as clinically indicated. Cocaine exposure was considered positive if either history or laboratory results were positive. Six years later, 665 families were contacted; 94% agreed to participate. The child, primary caretaker (parent), and, when available, the biologic mothers were tested in our research facilities. Permission was elicited to obtain blinded teacher assessments of child behavior with the Achenbach Teachers Report Form (TRF). Drug use since the childs birth was assessed by trained researchers using a structured interview. Results. Complete laboratory and teacher data were available for 499 parent–child dyads, with a final sample size for all analyses of 471 (201 cocaine-exposed) after the elimination of mentally retarded subjects. A comparison of relative Externalizing (Aggressive, Delinquent) to Internalizing (Anxious/Depressed, Withdrawn, Somatic Complaints) behaviors of the offspring was computed for the TRF by taking the difference between the 2 subscales to create an Externalizing–Internalizing Difference (T. M. Achenbach, personal communication, 1998). Univariate comparisons revealed that boys were significantly more likely to score in the clinically significant range on total TRF, Externalizing–Internalizing, and Aggressive Behaviors than were girls. Children prenatally exposed to cocaine had higher Externalizing–Internalizing Differences compared with controls but did not have significantly higher scores on any of the other TRF variables. Additionally, boys prenatally exposed to cocaine were twice as likely as controls to have clinically significant scores for externalizing (25% vs 13%) and delinquent behavior (22% vs 11%). Gender, prenatal exposures (cocaine and alcohol), and postnatal risk factors (custody changes, current drug use in the home, childs report of violence exposure) were all related to problem behaviors. Even after controlling for gender, other prenatal substance exposures, and home environment variables, cocaine-exposed children had higher Externalizing–Internalizing Difference scores. Prenatal exposure to alcohol was associated with higher total score, increased attention problems, and more delinquent behaviors. Prenatal exposure to cigarettes was not significantly related to the total TRF score or any of the TRF subscales. Postnatal factors associated with problem behaviors included both changes in custody status and current drug use in the home. Change in custody status of the cocaine-exposed children, but not of the controls, was related to higher total scores on the TRF and more externalizing and aggressive behaviors. Current drug use in the home was associated with higher scores on the externalizing and aggressive subscales. Conclusions. Results of this study suggest gender-specific behavioral effects related to prenatal cocaine exposure. Prenatal alcohol exposure also had a significant impact on the TRF. Postnatal exposures, including current drug use in the home and the childs report of violence exposure, had an independent effect on teacher-assessed child behavioral problems. Furthermore, among the children prenatally exposed to cocaine, change in the childs custody status was a significant predictor of TRF scores. It remains possible that other unmeasured postnatal characteristics of the cocaine-using household may play important roles in teacher-assessed child behavior.

Significant Determinants of Susceptibility to Alcohol Teratogenicity

Typically, the rate of abusive drinking during pregnancy considerably exceeds the rates of fetal alcohol syndrome (FAS) and alcohol-related birth defects, suggesting that other factors may modify the impact of alcohol on the developing organism. Data in the literature supporting this susceptibility hypothesis are sparse. In this paper, two studies in different samples, using different analytic strategies to examine susceptibility to different adverse outcomes are presented. Among 176 pregnancies in which lowered birth weight for gestational age was detected as an effect attributable to frequent beer drinking, 27 infants weighted less than 2,700 grams and 149 weighed more. Using discriminant analysis to contrast these groups, lowered birth weight for gestational age was associated with black race and lower maternal weight and weight gain. The effects of these factors were additive with that of persistent alcohol exposure; no interactions were detected, but pregnancies with risks in addition to alcohol were more likely to yield growth-retarded infants. In a second study, pregnancies resulting in 25 FAS cases were contrasted with 50 controls. A four-factor model accounted for nearly two-thirds of the explainable variance in the occurrence of FAS. Adjusted for frequency of maternal drinking, chronic alcohol problems and parity, there was a sevenfold increase in risk for FAS among black infants. The findings from both studies are consistent with the susceptibility hypothesis and have potentially important implications for public health and clinical approaches to prevention, as well as for future research.

Analysis of Variance in Small Group Research

This paper discusses an ANOVA design appropriate for small group research in which dependent variables are derived from individual member responses. In such instances, subjects are nested within groups and groups are nested within treatments. Conditions under which it would be appropriate to pool the subjects within groups means square with the groups mean square to form the error term for the ANOVA are discussed. Such an error term will have somewhat greater power than that based on the groups means square alone. A common practice of using the subjects within groups mean square alone as the error term is shown to be inappropriate.