Abuse-like toluene exposure during early adolescence alters subsequent ethanol and cocaine behavioral effects and brain monoamines in male mice

Currently, there is a gap in understanding the neurobiological impact early adolescent toluene exposure has on subsequent actions of other drugs. Adolescent (PND 28-32) male Swiss-Webster mice (N = 210) were exposed to 0, 2000, or 4000 ppm of toluene vapor for 30 min/day for 5 days. Immediately following the last toluene exposure (PND 32; n = 15) or after a short delay (PND 35; n = 15), a subset of subjects' brains was collected for monoamine analysis. Remaining mice were assigned to one of two abstinence periods: a short 4-day (PND 36) or long 12-day (PND 44) delay after toluene exposure. Mice were then subjected to a cumulative dose response assessment of either cocaine (0, 2.5, 5, 10, 20 mg/kg; n = 60), ethanol (0, 0.5, 1, 2, 4 g/kg; n = 60), or saline (5 control injections; n = 60). Toluene concentration-dependently increased locomotor activity during exposure. When later challenged, mice exposed previously to toluene were significantly less active after cocaine (10 and 20 mg/kg) compared to air-exposed controls. Animals were also less active at the highest dose of alcohol (4 g/kg) following prior exposure to 4000 ppm when compared to air-exposed controls. Analysis of monoamines and their metabolites using High Pressure Liquid Chromatography (HPLC) within the medial prefrontal cortex (mPFC), nucleus accumbens (NAc), dorsal striatum (dSTR), and ventral tegmental area (VTA) revealed subtle effects on monoamine or metabolite levels following cumulative dosing that varied by drug (cocaine and ethanol) and abstinence duration. Our results suggest that early adolescent toluene exposure produces behavioral desensitization to subsequent cocaine-induced locomotor activity with subtle enhancement of ethanol's depressive effects and less clear impacts on levels of monoamines.

Childhood Violence Exposure Predicts High Blood Pressure in Black American Young Adults

OBJECTIVE

To test the impact of childhood adversity, including community violence exposure, on hypertension risk in Black American young adults to understand what risk factors (eg, prenatal factors, later exposures) and ages of adversity exposure increased hypertension risk.

STUDY DESIGN

The study included 396 Black American participants with data from prenatal, birth, and age 7-, 14-, and 19-year visits. At age 19 years, individuals with blood pressure (BP) measures >120 mmHg systolic and/or >80 mmHg diastolic were classified as having high blood pressure (HBP), and those with BP <120/80 mmHg were classified as normal. Associations between prenatal and birth risk factors; childhood adversity at age 7, 14, and 19 years; age 19 body mass index (BMI); and both systolic and diastolic BP at age 19 were tested using logistic regression models.

RESULTS

Age 19 BMI was positively associated with systolic and diastolic HBP status at age 19. Controlling for all covariates, community violence exposure at age 7 and 19 years was associated with 2.2-fold (95% CI, 1.242-3.859) and 2.0-fold (95% CI, 1.052-3.664) greater odds of systolic HBP, respectively, at age 19 years. Prenatal risk, birth risk, and other dimensions of childhood adversity were not associated with HBP in this cohort.

CONCLUSION

Childhood community violence exposure is a significant risk factor for HBP in young adults. As Black American children typically experience more community violence exposure than other American children, our results suggest that racial disparities in childhood community violence exposure may contribute to racial disparities in adult hypertension burden.

Effects of inhaled combined Benzene, Toluene, Ethylbenzene, and Xylenes (BTEX): Toward an environmental exposure model

Combined environmental exposures to the volatile organic compounds (VOCs) Benzene, Toluene, Ethylbenzene, and Xylene (BTEX) pose clear risks to public health. Research into these risks is under-studied even as BTEX levels in the atmosphere are predicted to rise. This review focuses on the available literature using single- and combined-BTEX component inhaled solvent exposures in animal models, necessarily also drawing on findings from models of inhalant abuse and occupational exposures. Health effects of these exposures are discussed for multiple organ systems, but with particular attention on neurobehavioral outcomes such as locomotor activity, impulsivity, learning, and psychopharmacological responses. It is clear that animal models have significant differences in the concentrations, durations and patterns of exposure. Experimental evidence of the deleterious health and neurobehavioral consequences of exposures to the individual components of BTEX were found, but these effects were typically assessed using concentrations and exposure patterns not characteristic of environmental exposure. Future studies with animal models designed appropriately to explore combined BTEX will be necessary and advantageous to discovering health outcomes and more subtle neurobehavioral impacts of long-term environmental exposures.

Prenatal Alcohol Screening During Pregnancy by Midwives and Nurses

BACKGROUND

Alcohol use during pregnancy can have a variety of harmful consequences on the fetus. Lifelong effects include growth restriction, characteristic facial anomalies, and neurobehavioral dysfunction. This range of effects is known as fetal alcohol spectrum disorders (FASD). There is no amount, pattern, or timing of alcohol use during pregnancy proven safe for a developing embryo or fetus. Therefore, it is important to screen patients for alcohol use, inform them about alcohol's potential effects during pregnancy, encourage abstinence, and refer for intervention if necessary. However, how and how often nurses and midwives inquire about alcohol drinking during pregnancy or use recommended screening tools and barriers they perceive to alcohol screening has not been well established.

METHODS

This survey was sent to about 6,000 American midwives, nurse practitioners, and nurses who provide prenatal care about their knowledge of the effects of prenatal alcohol exposure, the prevalence of alcohol use during pregnancy, and practices for screening patients' alcohol use. Participants were recruited by e-mail from the entire membership roster of the American College of Nurse-Midwives.

RESULTS

There were 578 valid surveys returned (about 9.6%). Analyses showed that 37.7% of the respondents believe drinking alcohol is safe during at least one trimester of pregnancy. Only 35.2% of respondents reported screening to assess patient alcohol use. Only 23.3% reported using a specific screening tool, and few of those were validated screens recommended for use in pregnant women. Respondents who believe alcohol is safe at some point in pregnancy were significantly less likely to screen their patients.

CONCLUSIONS

Respondents who reported that pregnancy alcohol use is unsafe felt more prepared to educate and intervene with patients regarding alcohol use during pregnancy and FASD than respondents who reported drinking in pregnancy was safe. Perceived alcohol safety and perceived barriers to screening appeared to influence screening practices. Improving prenatal care provider knowledge about the effects of prenatal alcohol exposure and the availability of valid alcohol screening tools will improve detection of drinking during pregnancy, provide more opportunities for meaningful intervention, and ultimately reduce the incidence of FASD.

Violence exposure, conflict, and health outcomes in inner-city African American adolescents

PURPOSE

To examine relationships among community and school violence exposure, parent-adolescent conflict, coping style, and self-reported health in a sample of 432 high-risk, inner-city African American adolescents at age 14 years.

DESIGN AND METHODS

Multiple regression and principal component analysis were used to analyze the secondary data. After controlling for multiple covariates (eg, sex, age, blood lead levels, and socioeconomic status), both violence exposure and posttraumatic stress symptoms (PTSS) were related to health outcomes. The survey of exposure to community violence, the safe-school survey, and the conflict tactics scale were used to measure community violence, school violence, and parent-adolescent conflict. Coping was evaluated using the general coping scale. The child health illness profile-adolescent edition was used to obtain self-reported health measures, and the clinician-assisted PTSD scale was used to measure PTSS.

RESULTS

Higher exposure to community violence was associated with less emotional comfort, less family involvement, higher individual risk, and poorer academic and work performance. Parent-adolescent conflict predicted less physical and emotional comfort and poorer home safety and health.

CONCLUSIONS

Our findings suggest that it is important to evaluate both violence exposure and the responses to the exposure, which can include both PTSS and diverse coping strategies.

Prenatal toluene exposure impairs performance in the Morris Water Maze in adolescent rats

Volatile organic solvent abuse continues to be a worldwide health problem, including the neurobehavioral teratogenic sequelae of toluene abuse during pregnancy. Although abuse levels of prenatal toluene exposure can lead to a Fetal Solvent Syndrome, there is little research examining these effects on memory. Consumption of toluene can have detrimental effects on the developing hippocampus which could lead to specific spatial learning and memory deficits. This study used a rat model to determine how prenatal exposure to abuse levels of toluene would affect performance in a spatial learning and memory task, the Morris Water Maze (MWM). Pregnant Sprague-Dawley rats were exposed to 0, 8000 or 12,000ppm (ppm) of toluene for 15min twice daily from gestation day 8 (GD8) through GD20. Male and female offspring (N=104) were observed in the MWM for 5days beginning on postnatal day (PN) 28 and again on PN44. While prenatal toluene-exposed animals did not differ in initial acquisition in the MWM, rats prenatally exposed to 12,000ppm toluene displayed performance deficits during a probe trial and in reversal learning on PN44. Overall, this study indicates that prenatal exposure to repeated inhaled abuse patterns of high concentrations of toluene can impair spatial memory function that persists into adolescence.

Parental Support, Mental Health, and Alcohol and Marijuana Use in National and High-Risk African-American Adolescent Samples

African-American adolescents experience disproportionate rates of negative consequences of substance use despite using substances at average or below-average rates. Due to underrepresentation of African-American adolescents in etiological literature, risk and protective processes associated with their substance use require further study. This study examines the role of parental support in adolescents' conduct problems (CPs), depressive symptoms (DSs), and alcohol and marijuana use in a national sample and a high-risk sample of African-American adolescents. In both samples, parental support was inversely related to adolescent CPs, DSs, and alcohol and marijuana use. CPs, but not DSs, partially mediated the relation of parental support to substance use. Results were consistent across the national and high-risk samples, suggesting that the protective effect of parental support applies to African-American adolescents from a range of demographic backgrounds.

Prenatal alcohol exposure selectively enhances young adult perceived pleasantness of alcohol odors

Prenatal alcohol exposure (PAE) can lead to life-long neurobehavioral and social problems that can include a greater likelihood of early use and/or abuse of alcohol compared to older teens and young adults without PAE. Basic research in animals demonstrates that PAE influences later postnatal responses to chemosensory cues (i.e., odor & taste) associated with alcohol. We hypothesized that PAE would be related to poorer abilities to identify odors of alcohol-containing beverages, and would alter perceived alcohol odor intensity and pleasantness. To address this hypothesis we examined responses to alcohol and other odors in a small sample of young adults with detailed prenatal histories of exposure to alcohol and other drugs. The key finding from our controlled analyses is that higher levels of PAE were related to higher relative ratings of pleasantness for alcohol odors. As far as we are aware, this is the first published study to report the influence of PAE on responses to alcohol beverage odors in young adults. These findings are consistent with the hypothesis that positive associations (i.e., "pleasantness") to the chemosensory properties of alcohol (i.e., odor) are acquired prenatally and are retained for many years despite myriad interceding postnatal experiences. Alternate hypotheses may also be supported by the results. There are potential implications of altered alcohol odor responses for understanding individual differences in initiation of drinking, and alcohol seeking and high-risk alcohol-related behaviors in young adults.

Binge toluene exposure in pregnancy and pre-weaning developmental consequences in rats

Binge Toluene Exposure in Pregnancy and Pre-weaning Developmental Consequences in Rats. Bowen, S.E. and Hannigan, J.H. The persistent rate of abuse of inhaled organic solvents, especially among women of child-bearing age, raises the risk for teratogenic effects of maternal toluene abuse. In this study, timed-pregnant Sprague Dawley rats were exposed from Gestation Day (GD) 8 to GD20 to 12,000 or 8000 parts per million (ppm) toluene, or 0ppm (controls) for 30min twice daily, 60min total daily exposure. Pups were assessed from postnatal day (PN) 4 to PN21 using a developmental battery measuring growth (i.e., body weight), maturational milestones (e.g., eye opening & incisor eruption), and biobehavioral development (e.g., negative geotaxis & surface righting). Pups exposed in utero to 12,000ppm or 8000ppm toluene weighed significantly less than the non-exposed control pups beginning at PN4 and PN12 (respectively) until PN21. Toluene resulted in significant increases in an index of poor perinatal outcome, specifically a composite of malformations, defined "runting" and neonatal death. No significant delays were observed in reaching maturational milestones. The results reveal that brief, repeated, prenatal exposure to high concentrations of toluene can cause growth retardation and malformations in rats. A comparison of the present, conservative results with findings in previous studies implies that binge patterns of toluene exposure in pregnant rats modeling human solvent abuse can result in developmental and morphological deficits in offspring. These results do not exclude the possibility that maternal toxicity as well as teratogenic effects of toluene may contribute to outcomes. The results suggest that abuse of inhaled organic solvents like toluene may result in similar early developmental outcomes in humans.

Recognized spontaneous abortion in mid-pregnancy and patterns of pregnancy alcohol use

Alcohol consumption during pregnancy is one potential risk factor for spontaneous abortion (SAb). Prior research suggested that heavy drinking during pregnancy was associated with significantly increased rates of SAb, but results for lower levels of drinking have been inconsistent. We examined the association between different levels and patterns of prenatal alcohol consumption and SAb in a high-risk inner-city sample. We hypothesized that higher levels, binge patterns, and more frequent drinking would be associated with increased rates of SAb. The quantity and frequency of self-reported peri-conceptional and repeated in-pregnancy maternal drinking volumes per beverage type were assessed with semi-structured interviews in a prospective subsample of 302 African-American mothers. Relations between various measures of prenatal alcohol exposure and SAb were assessed using logistic regression. After controlling for various potential confounders, there was a significant positive relation between average absolute alcohol use per day across pregnancy and SAb. Greater frequency of drinking episodes also predicted SAb: an average of even one day of drinking per week across pregnancy was associated with an increase in the incidence of SAb. However, contrary to our hypothesis, neither the amount of alcohol drunk per drinking day nor a measure of binge drinking was significantly related to SAb after controlling for confounders. Differences in when women who drank at risk levels initiated antenatal care may have under-estimated the impact of alcohol on SAb in this low-SES urban African-American sample. Some drinking measures averaged across pregnancy may have under-estimated consumption and overestimated risk of SAb, but other risk drinking measures that avoid this limitation show similar relations to SAb. Identifying fetal risk drinking in pregnant women is critical to increasing the effectiveness of interventions that reduce risk level alcohol consumption and protect from pregnancy loss.

Validity of the T-ACE in pregnancy in predicting child outcome and risk drinking

Preventing fetal alcohol spectrum disorders (FASDs) requires detection of in-pregnancy maternal risk drinking. The widely used T-ACE screen has been applied in various ways, although the impact of those different uses on effectiveness is uncertain. We examined relations among different T-ACE scoring criteria, maternal drinking, and child outcome. Self-reported across-pregnancy maternal drinking was assessed in 75 African-American women. The different T-ACE criteria used varied the level of drinking that defined tolerance (two or three drinks) and the total T-ACE score cut-points (two or three). Receiver operator curves and regression analysis assessed the significance of relations. Increasing the total T-ACE score cut-point to 3 almost doubled specificity in detecting risk drinking whereas maintaining adequate sensitivity, equivalent to that in the original report, and identified substantially more neurobehavioral deficits in children. Redefining tolerance at three drinks did not improve T-ACE effectiveness in predicting outcomes. This study is among the first to show the ability of an in-pregnancy T-ACE assessment to predict child neurodevelopmental outcome. In addition, increasing the total T-ACE score criterion (from 2 to 3) improved identification of non-drinking mothers and unaffected children with little loss in detection of drinkers and affected children. Efficient in-pregnancy screens for risk drinking afford greater opportunities for intervention that could prevent/limit FASDs.

A 14-year retrospective maternal report of alcohol consumption in pregnancy predicts pregnancy and teen outcomes

Detecting patterns of maternal drinking that place fetuses at risk for fetal alcohol spectrum disorders (FASDs) is critical to diagnosis, treatment, and prevention but is challenging because information on antenatal drinking collected during pregnancy is often insufficient or lacking. Although retrospective assessments have been considered less favored by many researchers due to presumed poor reliability, this perception may be inaccurate because of reduced maternal denial and/or distortion. The present study hypothesized that fetal alcohol exposure, as assessed retrospectively during child adolescence, would be related significantly to prior measures of maternal drinking and would predict alcohol-related behavioral problems in teens better than antenatal measures of maternal alcohol consumption. Drinking was assessed during pregnancy, and retrospectively about the same pregnancy, at a 14-year follow-up in 288 African-American women using well-validated semistructured interviews. Regression analysis examined the predictive validity of both drinking assessments on pregnancy outcomes and on teacher-reported teen behavior outcomes. Retrospective maternal self-reported drinking assessed 14 years postpartum was significantly higher than antenatal reports of consumption. Retrospective report identified 10.8 times more women as risk drinkers (≥ one drink per day) than the antenatal report. Antenatal and retrospective reports were moderately correlated and both were correlated with the Michigan Alcoholism Screening Test. Self-reported alcohol consumption during pregnancy based on retrospective report identified significantly more teens exposed prenatally to at-risk alcohol levels than antenatal, in-pregnancy reports. Retrospective report predicted more teen behavior problems (e.g., attention problems and externalizing behaviors) than the antenatal report. Antenatal report predicted younger gestational age at birth and retrospective report predicted smaller birth size; neither predicted teen IQ. These results suggest that if only antenatal, in-pregnancy maternal report is used, then a substantial proportion of children exposed prenatally to risk levels of alcohol might be misclassified. The validity of retrospective assessment of prior drinking during pregnancy as a more effective indicator of prenatal exposure was established by predicting more behavioral problems in teens than antenatal report. Retrospective report can provide valid information about drinking during a prior pregnancy and may facilitate diagnosis and subsequent interventions by educators, social service personnel, and health-care providers, thereby reducing the life-long impact of FASDs.

Just say "I don't": lack of concordance between teen report and biological measures of drug use

BACKGROUND

Prevalence estimates of illicit drug use by teens are typically generated from confidential or anonymous self-report. While data comparing teen self-report with biological measures are limited, adult studies identify varying degrees of under-reporting.

METHODS

Hair analyses for cocaine, opiates and marijuana were compared to confidential teen self- and parent-reported teen drug use in a longitudinal cohort of >400 high-risk urban teens and parents.

RESULTS

Both teens and parents substantially underreported recent teen cocaine and opiate use. However, compared with parents, teens were more likely to deny biomarker-verified cocaine use. Teen specimens (hair) were 52 times more likely to identify cocaine use compared with self-report. Parent hair analyses for cocaine and opiate use were 6.5 times and 5.5 times, respectively, more likely to indicate drug use than were parental self-report. The lack of concordance between self-report and bioassay occurred despite participant's knowledge that a "certificate of confidentiality" protected both teen and adult participants, and that the biological specimens would be tested for drugs.

CONCLUSIONS

These findings confirm prior reports of adult under-reporting of their own drug use while extending our understanding of teen's self-admitted drug use. The lack of concordance between teen self- or parent-reported teen drug use and biomarkers confirm our concerns that both teen- and parent-reported teen drug use is limited, at least for youth in high-risk urban settings. Methods of ascertainment other than self- or parent-report must be considered when health care providers, researchers and public health agencies attempt to estimate teen drug-use prevalence.

The impact of maternal age on the effects of prenatal alcohol exposure on attention

BACKGROUND

Prenatal exposure to alcohol has a variety of morphologic and neurobehavioral consequences, yet more than 10% of women continue to drink during pregnancy, placing their offspring at risk for fetal alcohol spectrum disorders (FASD). Identification of at-risk pregnancies has been difficult, in part, because the presence and severity of FASD are influenced by factors beyond the pattern of alcohol consumption. Establishing maternal characteristics, such as maternal age, that increase the risk of FASD is critical for targeted pregnancy intervention.

METHODS

We examined the moderating effect of maternal age on measures of attention in 462 children from a longitudinal cohort born to women with known alcohol consumption levels (absolute ounces of alcohol per day at conception) who were recruited during pregnancy. Analyses examined the impact of binge drinking, as average ounces of absolute alcohol per drinking day. Smoking and use of cocaine, marijuana, and opiates were also assessed. At 7 years of age, the children completed the Continuous Performance Test, and their teachers completed the Achenbach Teacher Report Form.

RESULTS

After controlling for covariates, stepwise multiple regression analyses revealed a negative relation between levels of prenatal binge drinking and several measures of attention. The interaction between alcohol consumption and maternal age was also significant, indicating that the impact of maternal binge drinking during pregnancy on attention was greater among children born to older drinking mothers.

CONCLUSION

These findings are consistent with previous findings that children born to older alcohol-using women have more deleterious effects of prenatal alcohol exposure on other neurobehavioral outcomes.

Differential effects of inhaled toluene on locomotor activity in adolescent and adult rats

Inhalant abuse is a world-wide public health concern among adolescents. Most preclinical studies have assessed inhalant effects in adult animals leaving unclear how behavioral effects differ in younger animals. We exposed adolescent (postnatal day [PN] 28) and adult (PN90) male rats to toluene using 1 of 3 exposure patterns. These patterns modeled those reported in toluene abuse in teens and varied concentration, number and length of exposures, as well as the inter-exposure interval. Animals were exposed repeatedly over 12 days to toluene concentrations of 0, 8000 or 16,000 parts per million (ppm). Locomotor activity was quantified during toluene exposures and for 30 min following completion of the final daily toluene exposure. For each exposure pattern, there were significant toluene concentration-related increases and decreases in locomotor activity compared to the 0-ppm "air" controls at both ages. These changes depended upon when activity was measured - during or following exposure. Compared to adults, adolescents displayed greater locomotor activity on the first day and generally greater increases in activity over days than adults during toluene exposure. Adults displayed greater locomotor activity than adolescents in the "recovery" period following exposure on the first and subsequent days. Age group differences were clearest following the pattern of paced, brief (5-min) repeated binge exposures. The results suggest that locomotor behavior in rats during and following inhalation of high concentrations of toluene depends on age and the pattern of exposure. The results are consistent with dose-dependent shifts in sensitivity and sensitization or tolerance to repeated toluene in the adolescent animals compared to the adult animals. Alternate interpretations are possible and our interpretation is limited by the range of very high concentrations of toluene used. The results imply that both pharmacological and psychosocial factors contribute to the teen prevalence of inhalant abuse.

Prenatal and postnatal cocaine exposure predict teen cocaine use

Preclinical studies have identified alterations in cocaine and alcohol self-administration and behavioral responses to pharmacological challenges in adolescent offspring following prenatal exposure. To date, no published human studies have evaluated the relation between prenatal cocaine exposure and postnatal adolescent cocaine use. Human studies of prenatal cocaine-exposed children have also noted an increase in behaviors previously associated with substance use/abuse in teens and young adults, specifically childhood and teen externalizing behaviors, impulsivity, and attention problems. Despite these findings, human research has not addressed prior prenatal exposure as a potential predictor of teen drug use behavior. The purpose of this study was to evaluate the relations between prenatal cocaine exposure and teen cocaine use in a prospective longitudinal cohort (n=316) that permitted extensive control for child, parent and community risk factors. Logistic regression analyses and Structural Equation Modeling revealed that both prenatal exposure and postnatal parent/caregiver cocaine use were uniquely related to teen use of cocaine at age 14 years. Teen cocaine use was also directly predicted by teen community violence exposure and caregiver negativity, and was indirectly related to teen community drug exposure. These data provide further evidence of the importance of prenatal exposure, family and community factors in the intergenerational transmission of teen/young adult substance abuse/use.

Teens with heavy prenatal cocaine exposure respond to experimental social provocation with escape not aggression

Preclinical data show that, compared to no exposure, prenatal cocaine exposure (PCE) has age-dependent effects on social interaction and aggression. The aim of this clinical study was to determine how heavy/persistent PCE--after controlling for other prenatal drug exposures, sex and postnatal factors--predicts behavioral sensitivity to provocation (i.e., reactive aggression) using a well-validated human laboratory model of aggression. African American teens (mean=14.2 years old) with histories of heavy/persistent PCE (maternal cocaine use ≥ 2 times/week during pregnancy, or positive maternal or infant urine/meconium test at delivery; n=86) or none/some exposure (NON: maternal cocaine use < 2 times/week during pregnancy; n=330) completed the Point Subtraction Aggression Paradigm. In this task, teens competed in a computer game against a fictitious opponent. There were three possible responses: (a) earn points, to exchange for money later; or (b) "aggress" against the fictitious opponent by subtracting their points; or (c) escape temporarily from point subtraction perpetrated by the fictitious opponent. The PCE group responded significantly more frequently on the escape option than the NON group, but did not differ in aggressive or money-earning responses. These data indicate that PCE-teens provoked with a social stressor exhibit a behavioral preference for escape (negative reinforcement) than for aggressive (retaliatory) or appetitive (point- or money-reinforced) responses. These findings are consistent with preclinical data showing that social provocation of adolescent or young adult offspring after PCE is associated with greater escape behavior, inferring greater submission, social withdrawal, or anxiety, as opposed to aggressive behavior.

Reproductive toxicology and teratology of abused toluene

Toluene is an organic solvent that is widely used by industry and is ubiquitous in our environment. As a result, exposure to solvents like toluene in work-related settings (i.e., relatively constant, low-level exposures) or through inhalant abuse (i.e., relatively intermittent, high-level exposures) is increasing for many women of reproductive age. Evidence suggests that the risk for pregnancy problems, as well as developmental delays and neurobehavioral difficulties, is higher for the children of women who have been exposed to high concentrations of organic solvents during pregnancy than for those who have not. These risks appear to be higher in cases of abuse exposure to solvents such as toluene, particularly in comparison to the risk for teratogenic outcomes with occupational solvent exposure. Despite this, the reproductive toxicology and teratology following abuse of toluene and other inhalants remains under-investigated. This brief review describes the current state of our understanding of the reproductive and teratogenic risk of gestational toluene abuse. The data to date suggest that the high levels of toluene exposure typical with inhalant abuse are more detrimental to fetal development than typical occupational exposure, and preclinical paradigms can be beneficial for investigating the processes and risks of prenatal solvent exposure. While substantial research has been done on the reproductive effects of occupational exposures to organic solvents, more research is needed on the outcomes and mechanisms of exposures typical of inhalant abuse.

Animal models of fetal alcohol spectrum disorders: impact of the social environment

Animal models of fetal alcohol spectrum disorder (FASD) have been used to demonstrate the specificity of alcohol's teratogenic effects and some of the underlying changes in the central nervous system (CNS) and, more recently, to explore ways to ameliorate the effects of alcohol. The main point of this review is to highlight research findings from the animal literature which point to the impact of the social context or social behavior on the effect(s) of alcohol exposure during development, and also to point to research questions about the social environment and effects of prenatal alcohol exposure that remain to be answered. Alcohol exposure during early development alters maternal responding to the exposed pup in a variety of ways and the alteration in maternal responding could alter later stress responsivity and adult maternal and social behavior of the exposed offspring. Environmental enrichment and voluntary exercise have been shown to ameliorate some of alcohol's impact during development, but the roles of enhanced social interactions in the case of enrichment and of social housing during voluntary exercise need to be more fully delineated. Similarly, the role of social context across the lifespan, such as social housing, social experiences, and contact with siblings, needs further study. Because of findings that alcohol during development alters DNA methylation patterns and that there are alterations in the maternal care of the alcohol-exposed offspring, epigenetic effects and their relationship to social behavior in animal models of FASD are likely to become a fruitful area of research. Because of the simpler social behavior and the short lifespan of rodents, animal models of FASD can be useful in determining how the social context impacts the effects of alcohol exposure during development.

Neurochemical changes after acute binge toluene inhalation in adolescent and adult rats: a high-resolution magnetic resonance spectroscopy study

Inhalant abuse in young people is a growing public health concern. We reported previously that acute toluene intoxication in young rats, using a pattern of exposures that approximate abuse patterns of inhalant use in humans, significantly altered neurochemical measures in select brain regions. In this study, adolescent and young adult rats were exposed similarly to an acute (2 x 15 min), high dose (8000-12,000 ppm) of toluene and high-resolution magic angle spinning proton magnetic resonance spectroscopy (HR-MAS 1H-MRS) was used to assess neurochemical profiles of tissue samples from a number of brain regions collected immediately following solvent exposure. The current investigation focused on N-acetyl-aspartate (NAA), choline-containing compounds, creatine, glutamate, GABA, and glutamine. Contrary to our predictions, no significant alterations were found in the levels of NAA, choline, creatine, glutamate, or glutamine in adolescent animals. In contrast to these minimal effects in adolescents, binge toluene exposure altered several neurochemical parameters in young adult rats, including decreased levels of choline and GABA in the frontal cortex and striatum and lowered glutamine and NAA levels in the frontal cortex. One of the more robust findings was a wide-ranging increase in lactate after toluene exposure in adult animals, an effect not observed in adolescents. These age-dependent effects of toluene are distinct from those reported previously in juvenile rats and suggest a developmental difference in vulnerability to the effects of inhalants. Specifically, the results suggest that the neurochemical response to toluene in adolescents is attenuated compared to adults, and imply an association between these neurochemical differences and age-influenced differences in solvent abuse in humans.

Alterations in rat fetal morphology following abuse patterns of toluene exposure

Toluene is a commonly abused organic solvent. Inhalant abusers are increasingly women in their prime childbearing years. Children born to mothers who abused solvents during pregnancy may exhibit characteristics of a "fetal solvent syndrome" which may include dysmorphic features. This study examined the teratological effects of an abuse pattern of binge toluene exposure during gestation on skeletal and soft tissue abnormalities, body weight, and body size in fetal rats. Pregnant Sprague-Dawley rats were exposed for 30 min, twice daily, from gestational day (GD) 8 through GD20 to either air (0 ppm), 8000 ppm, 12,000 ppm, or 16,000 ppm toluene. Two-thirds of each litter was prepared for skeletal examination using Alizarin Red S staining while the remaining third of each litter was fixed in Bouin's solution for Wilson's soft tissue evaluation. Exposure to toluene at all levels significantly reduced growth, including decreases in placental weight, fetal weight, and crown-rump length. In addition, numerous gross morphological anomalies were observed such as short or missing digits and missing limbs. Skeletal examination revealed that ossification of the extremities was significantly reduced as a result of toluene exposure at all levels. Specific skeletal defects included misshapen scapula, missing and supernumerary vertebrae and ribs, and fused digits. Soft tissue anomalies were also observed at all toluene levels and there was a dose-dependent increase in the number of anomalies which included cryptorchidism, displaced abdominal organs, gastromegaly, distended/hypoplastic bladder, and delayed cardiac development, among others. These results indicate that animals exposed prenatally to levels and patterns of toluene typical of inhalant abuse are at increased risk for skeletal and soft tissue abnormalities.

Environmental enrichment alters neurotrophin levels after fetal alcohol exposure in rats

BACKGROUND

Prenatal alcohol exposure causes abnormal brain development, leading to behavioral deficits, some of which can be ameliorated by environmental enrichment. As both environmental enrichment and prenatal alcohol exposure can individually alter neurotrophin expression, we studied the interaction of prenatal alcohol and postweaning environmental enrichment on brain neurotrophin levels in rats.

METHODS

Pregnant rats received alcohol by gavage, 0, 4, or 6 g/kg/d (Zero, Low, or High groups), or no treatment (Naïve group), on gestational days 8 to 20. After weaning on postnatal day 21, offspring were housed for 6 weeks in Isolated, Social, or Enriched conditions. Levels of nerve growth factor (NGF), brain-derived neurotrophic factor (BDNF), and neurotrophin-3 (NT-3) were then measured in frontal cortex, occipital cortex, hippocampus, and cerebellar vermis.

RESULTS

Prenatal alcohol exposure increased NGF levels in frontal cortex (High-dose group) and cerebellar vermis (High- and Low-dose groups); increased BDNF in frontal cortex, occipital cortex and hippocampus (Low-dose groups), and increased NT-3 in hippocampus and cerebellar vermis (High-dose). Environmental enrichment resulted in lower NGF, BDNF, and NT-3 levels in occipital cortex and lower NGF in frontal cortex. The only significant interaction between prenatal alcohol treatment and environment was in cerebellar vermis where NT-3 levels were higher for enriched animals after prenatal alcohol exposure, but not for animals housed under Isolated or Social conditions.

CONCLUSIONS

Both prenatal alcohol exposure and postweaning housing conditions alter brain neurotrophin levels, but the effects appear to be largely independent. Although environmental enrichment can improve functional outcomes, these results do not provide strong support for the hypothesis that rearing in a complex environment ameliorates prenatal alcohol effects on brain neurotrophin levels in rats.

Neonatal alcohol-induced region-dependent changes in rat brain neurochemistry measured by high-resolution magnetic resonance spectroscopy

BACKGROUND

Maternal drinking during pregnancy can lead to a range of deleterious outcomes in the developing offspring that have been collectively termed fetal alcohol spectrum disorders (FASDs). There is interest and recognized value in using non-invasive neuroimaging techniques such as magnetic resonance imaging (MRI) and magnetic resonance spectroscopy (MRS) to characterize, respectively, structural and biochemical alterations in individuals with FASDs. To date, however, results with MRS have been inconsistent regarding the degree and/or nature of abnormalities.

METHODS

High-resolution magic angle spinning (HR-MAS) proton ((1)H) MRS is an ex vivo neuroimaging technique that can acquire spectra in small punches of intact tissue, providing clinically relevant neurochemical information about discrete brain regions. In this study, HR-MAS (1)H MRS was used to examine regional neurochemistry in frontal cortex, striatum, hippocampus, and cerebellum of young rats previously exposed to ethanol as neonates. Key neurochemicals of interest included N-acetyl-aspartate (NAA), glutamate, GABA, glutamine, creatine, choline and myo-inositol.

RESULTS

Daily neonatal alcohol exposure from postnatal day 4 (PN4) through PN9 significantly reduced levels of NAA and taurine in the cerebellum and striatum, and induced sex-dependent reductions in cerebellar glutamate when measured on PN16. In addition, myo-inositol was significantly increased in cerebellum. The frontal cortex and hippocampus were virtually unaffected by this neonatal alcohol exposure.

CONCLUSION

Results of this research may have implications for understanding the underlying neurobiology associated with FASDs and aid in testing treatments in the future. Ongoing studies are assessing the developmental persistence of and/or maturational recovery from these changes.

Maternal and fetal blood and organ toluene levels in rats following acute and repeated binge inhalation exposure

Inhalation of organic solvents is a persistent form of drug abuse with particular concern being the abuse of inhalants by women of child-bearing age. While studies have begun assessing postnatal outcomes of offspring exposed prenatally to inhalants, relatively little is known about the distribution of toluene in blood and body tissues of pregnant, inhalant-abusing women, or in the fetuses. The present study assessed the tissue toluene levels attained following brief toluene exposures using a pre-clinical rat model of maternal inhalant abuse. Timed-pregnant Sprague-Dawley rats were exposed to toluene at 8000 or 12,000 parts per million (ppm) for 15, 30 or 45 min/exposure. Exposures occurred twice each day from gestational day 8 (GD8) through GD20. Immediately following the second exposure on GD8, GD14 and GD20 blood was taken from the saphenous vein of the dams. Following saphenous vein blood collection on GD20, dams were sacrificed and trunk blood was collected along with maternal tissue specimens from cerebellum, heart, lung, kidney and liver. The placenta, amniotic fluid and fetal brain were also collected. Results demonstrated that maternal saphenous blood toluene levels increased as the inhaled concentration of toluene and duration of exposure increased. The maternal cerebellum, heart, kidney and liver appeared to be saturated after 30 min on GD20 such that toluene levels in those organs were equivalent across all ambient concentrations of inhaled toluene. Toluene levels also increased in fetal brain as the inhaled concentration of toluene increased and in placenta and amniotic fluid as the duration of exposure increased. Toluene levels in all tissues at GD20, except maternal lung and amniotic fluid, were higher than in maternal saphenous blood suggesting that toluene concentrated in those organs. Measurement of toluene levels in blood and other tissues following repeated toluene exposure demonstrated that toluene readily reaches a variety of potential sites of action throughout the maternal-placental-fetal unit.

Blood lead levels and specific attention effects in young children

The detrimental effects of early exposure to lead are credible and persistent, but there is presently no agreement on a safe threshold for circulating lead levels. Although several research groups have found significantly poorer cognitive performance in children who have whole blood levels as low as 5 microg/dL, most government agencies, including the EPA and the CDC, continue to use 10 microg/dL as the criterion for concern in public health advisories. Prior research has consistently indicated a negative relation between lead levels and attention. Similarly, the results of the present study show a relation between blood lead level and neurobehavioral outcome in 7-year-old children (N=506). Higher lead levels were associated significantly with decreased scores on measures of intelligence (i.e., overall, performance and verbal IQ), lengthened reaction time, hyperactivity, and social and delinquent behavior problems. Importantly, the present study documents a significant negative impact of blood lead levels on attention, but not impulsivity, in early elementary age children, further delineating the specific aspects of attention related to blood lead concentrations. Analyses were also conducted to identify a "safe" blood lead level threshold. Visual inspection of non-parametric regression plots suggested a gradual linear dose-response relationship for each endpoint. None of the neurobehavioral outcomes assessed showed evidence of a threshold under which lead levels appear to "safe". In light of the consistency of these findings with those of several other groups, it is advisable to consider whether the threshold for an acceptable blood lead level should be reduced.

Region-dependent alterations in glutamate and GABA measured by high-resolution magnetic resonance spectroscopy following acute binge inhalation of toluene in juvenile rats

Little is known about the neurochemical effects accompanying the high-concentration inhalant exposures characteristic of binge solvent abuse. In adult animals, prior studies with other patterns of exposure indicate that toluene, a commonly abused household and industrial solvent, has significant effects on the glutamatergic and GABAergic neurotransmitter systems and on other neurotransmitter systems as well. In the current investigation, high-resolution "magic angle" spinning proton magnetic resonance spectroscopy (HR-MAS (1)H-MRS) was used to assess the effect of acute binge toluene inhalation on regional brain concentrations of various neurochemicals including glutamate (GLU), GABA, and glutamine (GLN) in juvenile male and female rats. Acute toluene (8000 ppm or 12,000 ppm) significantly reduced levels of hippocampal GABA (-12%) and GLU (-8%), and the GLU/GLN ratio, an index of glutamatergic tone, was significantly reduced (-22%) in the dorsal anterior striatum, driven largely by a 28% increase in GLN. Significant increases in alanine and lactate in several brain regions after acute toluene may be indicative of altered oxygen-dependent metabolism associated with the inhalation of higher concentrations of toluene (e.g., >5000 ppm). Other components of the MR-visible neurochemical profile, such as N-acetylaspartate (NAA), myo-inositol, creatine, and various choline containing compounds, were unchanged by acute toluene. The results are consistent with the notion that binge toluene exposure affects juvenile neurochemistry in systems mediating the rewarding and emotional aspects of substance abuse. Moreover the results provide a framework to understand further (1)H-MRS studies in clinical populations.

Maternal smoking is associated with decreased 5-methyltetrahydrofolate in cord plasma

BACKGROUND

Maternal-fetal folate transport via the placenta has been shown to be concentrative. Exposure to cigarette smoke is associated with decreased maternal folate status through altered dietary intakes and possibly through nondietary mechanisms such as increased folate turnover. The effect of maternal smoking on fetal folate status has not been documented.

OBJECTIVE

The objective was to determine the effect of maternal smoking on plasma 5-methyltetrahydrofolic acid (5-MTHFA) concentrations in umbilical cord blood.

DESIGN

African American women were recruited from an antenatal clinic in Detroit, MI. Plasma 5-MTHFA concentrations were measured in maternal-umbilical cord pairings (n = 58). The participants completed a structured interview to determine demographic characteristics, including smoking.

RESULTS

Concentrations of 5-MTHFA were significantly higher in venous cord plasma (16.8 +/- 7.5 ng/mL) than in maternal plasma (13.0 +/- 7.5 ng/mL) but remained associated (r = 0.60, P < 0.001) with each other. Cigarettes smoked by the mothers was negatively associated (r = -0.31, P = 0.019) with venous cord 5-MTHFA concentrations and remained so after control for maternal plasma 5-MTHFA and other variables. Venous cord plasma 5-MTHFA was significantly lower in smoking (15.1 +/- 7.6 ng/mL; n = 32) than in nonsmoking (19.0 +/- 7.0 ng/mL; n = 26) mothers.

CONCLUSIONS

Cord plasma 5-MTHFA concentrations were elevated relative to maternal blood, as expected, because the placenta is capable of concentrative folate transport to the fetus. The negative effect of maternal smoking on infant, but not on maternal, 5-MTHFA status indicates that maternal smoking may impair folate transport to the fetus.

The role of maternal acceptance in the relation between community violence exposure and child functioning

Children in the United States are exposed to considerable community violence that has been linked to child functioning. However, not all those exposed, experience negative outcomes. Recent research has focused on factors that "buffer" or protect children from negative consequences of violence exposure. The purpose of this investigation was to examine the potential buffering or moderating role of maternal acceptance in the relationship between community violence exposure and internalizing and externalizing problems. Subjects were 268 urban African American first graders. Community violence exposure was significantly related to symptoms of post-traumatic stress, but did not correlate with either internalizing or externalizing problems for all children, after control for demographics, maternal mental health, and general life stress. However, children's perceptions of maternal acceptance moderated the relationship between violence exposure and internalizing and externalizing problems which included being withdrawn, anxious-depressed, and demonstrating delinquent behavior. Children with the lowest levels of self-reported maternal acceptance were most impacted by community violence. In this sample of urban first graders, low levels of maternal acceptance placed children at greater risk for adverse outcomes associated with community violence exposure compared to moderate and high levels of maternal acceptance.

Fatty acid ethyl esters in meconium: are they biomarkers of fetal alcohol exposure and effect?

BACKGROUND

Biomarkers of fetal exposure to alcohol are important to establish so that early detection and intervention can be made on these infants to prevent undesirable outcomes. The aim of this study was to analyze long-chain fatty acid ethyl esters (FAEEs) in meconium as potential biomarkers of fetal alcohol exposure and effect.

METHODS

Fatty acid ethyl esters were analyzed in the meconium of 124 singleton infants by positive chemical ionization gas chromatography/mass spectrometry (GC/MS) and correlated to maternal ethanol use.

RESULTS

A total of 124 mother/infant dyads were enrolled in the study: 31 were in the control group and 93 were in the alcohol-exposed group. The incidence (28% vs 9.7%, p = 0.037) of ethyl linoleate detected in meconium was significantly higher in the alcohol-exposed groups than the control groups. Similarly, when the concentrations of ethyl linoleate in meconium were grouped (trichotomized), there was a significant linear by linear association between alcohol exposure and group concentrations of ethyl linoleate (p = 0.013). Furthermore, only alcohol-exposed infants were found in the group with the highest ethyl linoleate concentration. The sensitivity of ethyl linoleate in detecting prenatal alcohol exposure was only 26.9%, and its specificity and positive predictive value were 96.8 and 96.2%, respectively. There was no significant correlation between the concentration of ethyl linoleate in meconium and absolute alcohol consumed (oz) per drinking day across pregnancy, although a trend toward a positive correlation is seen at lower amounts of alcohol consumed. Among the polyunsaturated, long-chain FAEEs, there was weak evidence that the incidence (21.5% vs 6.5%, p = 0.057) and concentration (p = 0.064) of ethyl arachidonate (AA) were significantly higher in the alcohol-exposed groups than the control groups. Ethyl linolenate and ethyl docosahexanoate (DHA) in meconium were found only in the alcohol group, although not at statistically significant levels. Highly significant correlations were found among the concentrations of ethyl linoleate, ethyl linolenate, ethyl AA, and ethyl DHA in meconium (correlations ranged between rs = 0.203, p = 0.024; and rs = 0.594, p < 0.001).

CONCLUSION

We conclude that FAEEs in meconium, particularly ethyl linoleate and ethyl AA, are biomarkers of high specificity for prenatal exposure to alcohol in newborn infants. We also propose that ethyl AA and DHA could be potential biomarkers of fetal alcohol effects on the developing fetal brain and should be investigated further.

Gestational toluene exposure effects on spontaneous and amphetamine-induced locomotor behavior in rats

Gestational Toluene Exposure Effects on Spontaneous and Amphetamine-Induced Locomotor Behavior in Rats. Bowen, S.E., Mohammadi, M.H., Batis, J.C., and Hannigan, J.H. Neurotoxicology and Teratology, XX, 2006. The abuse of volatile organic solvents (inhalants) continues to be a major health concern throughout the world. Toluene, which is found in many products such as glues and household cleaners, is among the most commonly abused organic solvents. The neurobehavioral teratogenic sequelae of solvent abuse (i.e., repeated, brief inhalation exposures to very high concentrations of solvents) have not been examined thoroughly. In a preclinical model of inhalant abuse, timed-pregnant Sprague-Dawley rats were exposed to 0, 8000, or 12,000 parts per million (ppm) for 15 min twice daily from gestation day 8 (GD8) through GD20. In the first experiment, separate groups of offspring were observed individually in an open-field on postnatal day 22 (PN22), PN42 or PN63. In the second experiment, other offspring given identical prenatal toluene exposures were observed in an "open-field" following an acute i.p. injection of amphetamine (0, 0.56, 1.78 mg/kg) on PN28. Automated measurements of distance traveled and ambulatory time were recorded. Prenatal toluene exposure resulted in small alterations in spontaneous activity compared to non-exposed rats. Prenatal exposure to 12,000 ppm toluene resulted in significant hyposensitivity to the locomotor stimulatory effects of the amphetamine challenge in male but not female rats on PN28. The results demonstrate that prenatal exposure to abuse patterns of high concentrations of toluene through inhalation can alter spontaneous and amphetamine-induced locomotor behavior in rats. The expression of these effects also appears to depend upon the postnatal age of testing. These results imply that abuse of organic solvents during pregnancy in humans may also produce long-lasting effects on biobehavioral development.

Postnatal environmental or experiential amelioration of neurobehavioral effects of perinatal alcohol exposure in rats

Fetal alcohol spectrum disorders (FASDs) in children are characterized by life-long compromises in learning, memory, and adaptive responses. To date, there are no clinical remedies for the treatment of global fetal alcohol effects, although interventions for specific outcomes are available. Here we review basic research in animal models of perinatal alcohol exposure to assess the potential of global environmental manipulations to ameliorate the neurobehavioral effects associated with FASD. Enhancement of the postnatal environment via neonatal handling, environmental enrichment, or rehabilitative or "therapeutic" motor training, can improve behavioral performance and ameliorate or even eliminate some deficits in perinatal alcohol-exposed rats and mice. While neuroanatomical changes associated with the behavioral improvements have been reported in some models, there generally appears to be a persistent impairment in neuronal plasticity. Such research suggests that it may be possible to manage the postnatal environment or experience of children with FASDs to improve function. It is, however, necessary to consider the difficulties in translating findings from research in animals to the clinic, school or home because sex-, postnatal age- and species-specific differences are critical factors in how specific environments may influence brain development. Continued study of the potential ameliorative effects of neonatal handling, environmental enrichment, and rehabilitative training as "therapies" in animal models will remain a valuable source of information for eventually devising treatments for children with FASDs.

Magnetic resonance and spectroscopic imaging in prenatal alcohol-exposed children: preliminary findings in the caudate nucleus

Magnetic resonance imaging (MRI) and magnetic resonance spectroscopic imaging (MRSI) offer unique, noninvasive methods of measuring, respectively, in vivo quantitative neuroanatomy and neurochemistry. The main purpose of the present study was to identify and compare the neuroanatomical and neurochemical abnormalities that are associated with prenatal exposure to alcohol in both fetal alcohol syndrome (FAS)-diagnosed children and those diagnosed with fetal alcohol effects (FAE). MR data of three age-, gender- and race-balanced groups of children, FAS-diagnosed, FAE-diagnosed and non-exposed controls, were compared. Effects of prenatal alcohol exposure, regardless of diagnosis, were found in the caudate nucleus. Specifically, a significantly smaller caudate nucleus was found for the FAS and FAE participants compared to the controls. In addition, the metabolite ratio of N-acetyl-aspartate to creatine (NAA/Cr), an indicator of neuronal function, in left caudate nucleus of both the FAS and FAE participants was elevated compared to the control group. Analysis of absolute concentrations revealed that the increase in the ratio of NAA/Cr was due to an increase in NAA alone. Although its exact function in the CNS is unknown, NAA is believed to be a neuronal marker due to its exclusive localization to neurons. Some also speculate a role for NAA in myelination. Elevated NAA in the prenatal alcohol-exposed participants could indicate a lack of normal program cell death, dendritic pruning and/or myelination during development. The present study demonstrates that prenatal alcohol-exposed children, with or without facial dysmorphology, have abnormal brain anatomy and chemistry.

Developmental toxicity of prenatal exposure to toluene

Organic solvents have become ubiquitous in our environment and are essential for industry. Many women of reproductive age are increasingly exposed to solvents such as toluene in occupational settings (ie, long-term, low-concentration exposures) or through inhalant abuse (eg, episodic, binge exposures to high concentrations). The risk for teratogenic outcome is much less with low to moderate occupational solvent exposure compared with the greater potential for adverse pregnancy outcomes, developmental delays, and neurobehavioral problems in children born to women exposed to high concentrations of abused organic solvents such as toluene, 1,1,1-trichloroethane, xylenes, and nitrous oxide. Yet the teratogenic effects of abuse patterns of exposure to toluene and other inhalants remain understudied. We briefly review how animal models can aid substantially in clarifying the developmental risk of exposure to solvents for adverse biobehavioral outcomes following abuse patterns of use and in the absence of associated health problems and co-drug abuse (eg, alcohol). Our studies also begin to establish the importance of dose (concentration) and critical perinatal periods of exposure to specific outcomes. The present results with our clinically relevant animal model of repeated, brief, high-concentration binge prenatal toluene exposure demonstrate the dose-dependent effect of toluene on prenatal development, early postnatal maturation, spontaneous exploration, and amphetamine-induced locomotor activity. The results imply that abuse patterns of toluene exposure may be more deleterious than typical occupational exposure on fetal development and suggest that animal models are effective in studying the mechanisms and risk factors of organic solvent teratogenicity.

Reversal learning after prenatal or early postnatal alcohol exposure in juvenile and adult rats

Learning tasks that require the reversal of a previously learned contingency are disrupted in animals and humans exposed to alcohol during the perinatal period. The current experiments examined how varying the time of alcohol exposure and the age at which subjects were tested would affect the expression of reversal deficits in a T-maze task. Groups of rats were exposed to alcohol from gestational day (GD) 8 to GD20 or from postnatal day (PN) 4 to PN9, and then tested in a spatial reversal task at either PN28 or PN63. Results indicate that exposure to alcohol during the prenatal period did not lead to substantial dose-dependent reversal learning deficits in males or females at either age tested. However, exposure to alcohol during the early postnatal period, a period that corresponds to the third trimester in human neural development, selectively disrupted reversal learning performance in male rats at PN28 but not PN63. Statistically significant sex differences were seen when subjects were tested at PN63. These results demonstrate how the timing of alcohol exposure leads to variability in the age-dependent expression of learning deficits associated with fetal alcohol effects.

Somatic complaints in children and community violence exposure

Somatic complaints of children in primary care settings often go unexplained despite attempts to determine a cause. Recent research has linked violence exposure to stress symptomatology and associated somatic problems. Unknown, however, is whether specific physical symptom complaints can be attributed, at least in part, to violence exposure. Urban African-American 6- and 7-year-old children (N = 268), residing with their biological mothers, recruited before birth, and without prenatal exposure to hard illicit drugs participated. Children and mothers were evaluated in our hospital-based research laboratory, with teacher data collected by mail. Community violence exposure (Things I Have Seen and Heard), stress symptomatology (Levonn), and somatic complaints (teacher-and self-report items) were assessed. Additional data collected included prenatal alcohol exposure, socioeconomic status, domestic violence, maternal age, stress, somatic complaints and psychopathology, and child depression, abuse, and gender. Community violence witnessing and victimization were associated with stress symptoms (r = .26 and .25, respectively, p < .001); violence victimization was related to decreased appetite (r = .16, p < .01), difficulty sleeping (r = .21, p < .001), and stomachache complaints (r = .13, p < .05); witnessed violence was associated with difficulty sleeping (r = .13, p < .05) and headaches (r = .12, p < .05). All associations remained significant after control for confounding. Community violence exposure accounted for 10% of the variance in child stress symptoms, and children who had experienced community violence victimization had a 28% increased risk of appetite problems, a 94% increased risk of sleeping problems, a 57% increased risk of headaches, and a 174% increased risk of stomachaches. Results provide yet another possibility for clinicians to explore when treating these physical symptoms in children.

Alcohol consumption in pregnant, black women is associated with decreased plasma and erythrocyte docosahexaenoic acid

BACKGROUND

Inner-city, black women are among those groups that are at higher risk for having infants with fetal alcohol spectrum disorders that can include life-long neurobehavioral and cognitive impairments. Chronic alcohol consumption can decrease amounts of docosahexaenoic acid (DHA), a fatty acid that is essential for optimal infant neural and retinal development in a variety of tissues.

METHODS

Black women who presented at an inner-city antenatal clinic for their first prenatal visit were recruited into a longitudinal, observational study. Alcohol intake was determined by a structured interview. Participants provided blood specimens and completed food frequency surveys at 24 weeks of gestation, infant delivery, and 3 months postpartum. Fatty acid composition analyses were completed on 307, 260, and 243 for plasma and 278, 261, and 242 erythrocyte specimens at 24 weeks of gestation, delivery, and 3 months postpartum, respectively.

RESULTS

Proportion of drinking days at the first prenatal visit was associated with decreased DHA in plasma and erythrocytes throughout the study. This association was the strongest at 24 weeks of gestation. In addition, an interaction between proportion of drinking days at the time of conception and ounces of absolute alcohol per drinking day at the time of conception was detected and demonstrated that, in daily drinkers, high intakes of alcohol are associated with decreased DHA and arachidonic acid (AA) concentrations in plasma.

CONCLUSIONS

Frequent and high intakes of alcohol that have been previously associated with fetal alcohol spectrum disorders are also associated with decreased maternal DHA and AA plasma concentrations. The present findings indicate that maternal DHA deficiency is associated with high-risk drinking and may contribute to the mechanism(s) of alcohol-related neurodevelopmental disorders.

Status of plasma folate after folic acid fortification of the food supply in pregnant African American women and the influences of diet, smoking, and alcohol consumption

BACKGROUND

African American women and socioeconomically challenged women are at risk of compromised folate status and, thus, of folate-related birth defects. Data are limited on circulating folate concentrations in pregnant African American women after folic acid fortification of the food supply was implemented.

OBJECTIVE

The objective was to determine the influence of smoking and alcohol consumption on plasma 5-methyltetrahydrofolic acid (5-MTHFA) concentrations in pregnant African American women.

DESIGN

Alcohol consumption, smoking exposure, and other characteristics of pregnant African American women reporting to an inner-city antenatal clinic were assessed. At 24 wk of gestation, blood samples and food-frequency intake data were collected. Plasma 5-MTHFA concentrations were determined by liquid chromatography-mass spectrometry for 116 subjects and examined in a correlational study design.

RESULTS

Dietary folate and markers of alcohol consumption were positively associated, whereas exposure to smoke was negatively associated with plasma 5-MTHFA. More than one-half of the participants in this population failed to meet the recommended dietary allowance for dietary folate equivalents of 600 microg/d during pregnancy.

CONCLUSIONS

Most inner-city African American women are not meeting the recommended dietary allowance for dietary folate during pregnancy, and smoking may further compromise their folate status. Programs to reduce smoking and raise awareness about the importance of folate and multivitamin supplementation during pregnancy need to target this population.

Comparison of bloodstream fatty acid composition from African-American women at gestation, delivery, and postpartum

Our aim was to examine the docosahexaenoic acid (DHA; 22:6n-3) status of pregnant African-American women reporting to the antenatal clinic at Wayne State University in a longitudinal study design. Fatty acid compositions of plasma and erythrocyte total lipid extracts were determined and food frequency surveys were administered at 24 weeks of gestation, delivery, and 3 months postpartum for participants (n = 157). DHA (mean +/- SD) in the estimated total circulating plasma was similar at gestation (384 +/- 162 mg) and delivery (372 +/- 155 mg) but was significantly lower at 3 months postpartum (178 +/- 81 mg). The relative weight percentage of DHA and docosapentaenoic acid n-6 (DPAn-6; 22:5n-6) decreased postpartum, whereas their respective metabolic precursors, eicosapentaenoic acid (EPA; 20:5n-3) and arachidonic acid (AA; 20:4n-6), increased. Similar results were found in erythrocytes. Dietary intake of DHA throughout the study was estimated at 68 +/- 75 mg/day. The relative amounts of circulating DHA and DPAn-6 were increased during pregnancy compared with 3 months postpartum, possibly via increased synthesis from EPA and AA. The low dietary intake and blood levels of DHA in this population compared with others may not support optimal fetal DHA accretion and subsequent neural development.

Effects of alcohol intake during pregnancy on docosahexaenoic acid and arachidonic acid in umbilical cord vessels of black women

OBJECTIVE

Alcohol influences the intake and metabolism of several nutrients including long-chain polyunsaturated fatty acids (LC-PUFAs). The LC-PUFAs docosahexaenoic acid (DHA) and arachidonic acid (AA) are particularly crucial for intrauterine growth and brain development. We hypothesized that alcohol consumption adversely affects LC-PUFA levels in pregnant women and their newborn infants.

METHODS

Pregnant black women (N = 208) presenting at a core city antenatal clinic were screened and recruited. Shortly before delivery, maternal plasma was collected. After delivery, umbilical arteries and veins were dissected from the cords, total lipids were extracted from the vessel tissues and maternal plasma, and fatty acid levels were assayed by gas chromatography. For statistical analysis, subjects were categorized according to absolute alcohol intake per day (AAD) and absolute alcohol intake per drinking day (AADD) around the time of conception, with smoking and other potential confounders included in the analyses.

RESULTS

Significant differences in fatty acid composition of total lipid extracts were detected in umbilical cord vessels among the AADD groups: abstainers (AADD = 0), moderate drinkers (AADD < 130 g), and heavy drinkers (AADD > or = 130 g). DHA and AA content in the arterial umbilical vessel wall was approximately 14% and approximately 10% higher in the moderate (n = 127) and heavy (n = 32) alcohol groups, respectively, than in abstainers (n = 49). A small, nonsignificant increase ( approximately 3%) was seen in the umbilical vein for AA but not for DHA. Alcohol intake was positively correlated to both DHA and AA concentrations in the arterial vessel wall but to neither in the venous wall nor maternal plasma. Maternal plasma DHA was positively correlated with both umbilical arteries and vein DHA, but there were no significant correlations for AA between maternal plasma and either umbilical vessel.

CONCLUSIONS

Our findings indicate that alcohol intake during pregnancy is associated with altered DHA and AA status in fetal tissues. Although differences may be due to either metabolism and/or distribution, it is most likely a result of a direct influence of alcohol on fetal metabolism.

Abuse pattern of gestational toluene exposure and early postnatal development in rats

Inhalant abuse in the United States trails only alcohol, marijuana and nicotine abuse. Toluene, found in glues and cleaners, is among the most commonly abused inhalants. While teratogenicity due to occupational exposure to organic solvents (i.e., relatively long-term exposure to lower concentrations) has been studied, the teratogenic potential of organic solvent abuse (i.e., brief inhalation exposures to very high concentrations) has not been thoroughly examined. In a preclinical model of abuse patterns of fetal solvent exposure, timed-pregnant rats were exposed to 8000 parts per million (ppm) or 12,000 ppm of toluene, or to air (0 ppm), for 15 min twice daily from gestation day 8 (GD8) through GD20. After parturition, pups were tested from postnatal day 4 (PN4) to PN21 in a developmental test battery including measures of growth (i.e., body weight), maturational milestones (i.e., pinnae unfolding, incisor eruption and eye opening) and biobehavioral development (e.g., negative geotaxis, surface righting and grip strength). Pups exposed in utero to 12,000 ppm toluene weighed significantly less than the control pups at all ages before PN16. There were significant toluene-induced increases in an index of poor perinatal outcome (i.e., a combination of malformations, "runting" and neonatal death) and deficits in negative geotaxis. There were no significant delays in reaching maturational milestones. The results demonstrate that brief, repeated, prenatal exposure to high concentrations of toluene can cause growth restriction, malformation and impairments of biobehavioral development in rats. A comparison of the present outcomes to previous studies of occupational exposure patterns suggests that for a given daily "dose" of toluene, a binge pattern of exposure may pose a greater risk for fetal development. Since the pattern of exposure in this experiment models binge exposure in human solvent abuse, the results imply that abuse of inhaled organic solvents, such as toluene, can cause similar teratogenic outcomes in humans.

Gender and alcohol moderate prenatal cocaine effects on teacher-report of child behavior

Prenatal cocaine exposure has been associated with behavior problems at school age. However, the correspondence between use of cocaine and alcohol during pregnancy is often high, making appropriate allocation of variance and control for other exposures and their interactions difficult. Additionally, gender-specific effects are not typically reported. The purpose of the current study was to determine the degree to which gender-specific effects of prenatal cocaine exposure on teacher-reported child externalizing behavior problems were evident when evaluated in relation to prenatal alcohol exposure. Subjects were singleton infants of mothers who were prospectively evaluated during pregnancy. At age seven, 499 children (214 exposed prenatally to cocaine) were evaluated in our laboratory and teacher reports were solicited. Analyses stratified by gender and prenatal alcohol exposure status, and controlled for significant pre- and postnatal confounders, revealed that among boys with prenatal alcohol exposure, those with persistent cocaine exposure throughout pregnancy had significantly higher levels of Delinquent Behavior compared to boys with no cocaine exposure. Boys with any prenatal cocaine exposure were twice as likely as unexposed boys to have clinically significant Externalizing Behavior scores. However, no association was found between prenatal cocaine exposure and scores on Externalizing Behavior and specific syndromes for boys with no prenatal alcohol exposure. Among girls with no prenatal alcohol exposure, those with persistent cocaine exposure had significantly higher levels of Externalizing Behaviors and Aggressive Behaviors compared to girls with no prenatal cocaine exposure after control for confounding, and were almost five times as likely to have clinically significant Externalizing Behavior scores. However, for girls with prenatal alcohol exposure, no association between prenatal cocaine exposure and scores on Externalizing Behavior and specific syndromes was found after control for confounding. The current findings support gender- and alcohol-moderated effects of prenatal cocaine exposure on school-age teacher-reported child behavior problems. These findings are similar to what we have reported for independent parent-reported behavioral evaluation.

Gender and alcohol moderate caregiver reported child behavior after prenatal cocaine

OBJECTIVE

The concurrence of prenatal alcohol exposure with other drug exposure, low socioeconomic status and environmental risk factors may obscure associations, if any, between prenatal cocaine exposure and child outcomes. This study evaluates the effects of prenatal cocaine exposure on child behavior in analyses stratified by gender and prenatal alcohol exposure status.

METHODS

Maternal alcohol, cigarette, and illicit drug use were prospectively assessed by interview during pregnancy and postnatally. Maternal and neonatal urine were tested for drug exposure as clinically indicated. Caregiver report of child behavior was assessed with the Achenbach Child Behavior Checklist (CBCL). Dichotomous cocaine exposure was characterized as no (negative history and biologic markers), and any (positive history and/or biologic markers during pregnancy and/or positive urine screen at delivery from either mother or infant).

RESULTS

Prenatal cocaine exposure was associated with adverse effects on offspring behavior that were moderated by the gender of the offspring as well as prenatal alcohol exposure. For girls without prenatal alcohol exposure, 6.5% of the unique variance in behavior was related to prenatal cocaine exposure. For these girls, the odds of scoring in the abnormal range for Aggression was 17 times control levels (95% confidence limits 1.4 to 203). These findings, though significant, have wide confidence intervals and need to be replicated in larger cohorts and on longitudinal follow-up.

Prenatal exposure to binge drinking and cognitive and behavioral outcomes at age 7 years

OBJECTIVE

The goal of this study was to examine differential effects of amount and pattern of prenatal alcohol exposure on child outcome.

STUDY DESIGN

Alcohol use was assessed at each prenatal visit, and IQ and behavior were measured at age 7 years.

RESULTS

After control for confounders, the amount of exposure was unrelated to IQ score and behavior for >500 black 7-year-old children. However, children who were exposed to binge drinking were 1.7 times more likely to have IQ scores in the mentally retarded range and 2.5 times more likely to have clinically significant levels of delinquent behavior.

CONCLUSION

During prenatal care, clinicians should attend not only to amount but also to the pattern of alcohol intake, because of the elevated risk for cognitive deficits and long-term behavioral abnormality.

Prenatal cocaine: quantity of exposure and gender moderation

Animal but few human studies have demonstrated gender-influenced differences in outcome related to prenatal cocaine exposure. Pregnant participants in a prospective pregnancy study were interviewed for drug use. Exposure was considered positive if history or laboratory tests were positive. An ordinal measure of exposure was also constructed. Six years later, the child and primary caretaker were tested to assess drug use in the home since birth and teacher-assessed child behavior. Data were complete for 473 children (204 cocaine exposed). Twenty-four of the exposed children (12%) were considered to have persistent pregnancy exposure based on positive urine screen at delivery. Boys with any prenatal cocaine exposure scored significantly higher (more problem behaviors) than nonexposed boys on the hyperactivity item. In contrast, no similar cocaine effect was observed for girls. When cocaine exposure was expressed as the three-level ordinal variable, boys, but not girls, with persistent exposure had more behavior problems (0.5 to 1.0 SD higher). Even after control for important covariates, boys with persistent exposure had more problems in central processing, motor skills, handling abstract concepts, and passivity to the environment. The magnitude of the relations reported in this research were moderate to large. In summary, both gender and the level of exposure had a significant behavioral effect on school-age behavior. In these analyses, the behavior of boys, but not girls, prenatally exposed to cocaine was significantly and negatively affected, and these findings remained after control for covariates, including prenatal alcohol or other illicit drug exposures and postnatal drug use in the home.