Do Peers, Neighborhood Disorder, Religiosity, Spirituality, and Family Support Influence Polysubstance Use Among Older Youth Transitioning from Foster Care?

PURPOSE

Few studies have explored polysubstance use among youths aging out of foster care, despite higher rates of substance misuse for youths exiting foster care than those in the general population. Polysubstance use has been linked to substance use disorders, health problems, cognitive impairment, suicide, and overdose.

METHOD

This study investigates understudied risk and protective factors associated with polysubstance use with data from 384 youth who turned 17 years old between December 1, 2001, and June 30, 2003, and were transitioning out of foster care from the Missouri Children's Division. We conducted bivariate analyses with chi-square tests for categorical variables and Analysis of Variance with continuous independent variables. Then we conducted a multinomial logistic regression to explore differences between individuals who used 1 or no substances, individuals who used only alcohol and marijuana, and individuals who used 2 or more substances.

RESULTS

Bivariate analyses found that being white, having deviant peers, and living in a more disordered neighborhood were risk factors for polysubstance use. Multinomial logistic regression results found that being white (RR = 6.89, p < .001), having deviant peers (RR = 1.15, p < .001), and living in a more disordered neighborhood (RR = 1.13, p < .05), increased the risk engaging in polysubstance use.

DISCUSSION

Similar to findings in other studies, we found that deviant peers and neighborhood disorder increase the risk of polysubstance use, but family support, church attendance, and spirituality were not protective against polysubstance use.

CONCLUSION

Interventions should work to reduce deviant peer relationships among foster youth.

Spatiotemporal patterns in the prevalence of microscopic hepatic changes in Gulf of Mexico Tilefish (Lopholatilus chamaeleonticeps) and associations with hepatic PAHs

Following the 2010 Deepwater Horizon blowout, demersal longline surveys were conducted across the Gulf of Mexico (GoM) continental shelf to evaluate polycyclic aromatic hydrocarbon (PAH) exposure, tissue accumulation, and health indices in demersal fishes. Tilefish (Lopholatilus chamaeleonticeps), a target species due to Gulf-wide distribution with documented high exposure to PAHs, were collected in the north central GoM at repeat stations 2012 to 2015, and from the northwest GoM, Bay of Campeche, and Yucatán Shelf in 2015 and 2016. Liver samples (n = 239) were analyzed for microscopic hepatic changes (MHCs) by a board-certified veterinary pathologist. Histological analyzes identified 14 MHCs. Prevalence of MHCs was generally uniform throughout the GoM, except for low prevalence on the Yucatán Shelf. Inflammatory and vacuolar changes were most prevalent, while pre-neoplasia and neoplasia were rare. Tilefish sampled annually in the north central GoM showed increases in inflammatory MHCs and glycogen-type vacuolar change over time, while lipid-type vacuolar change decreased over time. Short-term exposure to PAHs was assessed by measuring PAH metabolites in bile (n = 100) using high performance liquid chromatography with fluorescence detection. Longer-term accumulation of PAHs in tissue was assessed by analyzing liver (n = 111) for PAHs and alkylated homologs using QuEChERS extractions and gas chromatography tandem mass spectrometry. Six MHCs including glycogen-type vacuolar change, biliary fibrosis, foci of cellular alteration, parasites, hepatocellular atrophy, and necrosis were significantly associated with hepatic PAH accumulation in Tilefish from the northern central GoM; however, no MHCs were associated with biliary PAH metabolites. Combined with previous studies of PAH exposure and health indices in north central GoM Tilefish post-Deepwater Horizon, which also identified decreases in hepatic lipid storage and Fulton's condition factor that were correlated to increasing PAH exposure, these data indicate concerning temporal trends and changes in hepatic energy storage.

Detection of long chain per- and polyfluoroalkyl substances (PFAS) in the benthic Golden tilefish (Lopholatilus chamaeleonticeps) and their association with microscopic hepatic changes

Oceans are major sinks for anthropogenic pollutants, including per- and polyfluoroalkyl substances (PFAS). Although PFAS have been detected in surface waters globally, this is the first report of PFAS in a deep (170-400 m) demersal species in the Gulf of Mexico (GoM). Golden Tilefish (Lopholatilus chamaeleonticeps) plasma extracts (n = 185) were investigated for the presence of PFAS using ultra-high performance liquid chromatography-tandem mass spectrometry. A subset of liver tissues (n = 51) were also analyzed for microscopic hepatic changes (MHCs). Overall, nine of the 110 PFAS targeted were detected in Tilefish plasma at relatively high frequencies. Plasma concentrations of total PFAS (Σ₉PFAS) ranged from below the detection limit to 27.9 ng g^-1 w.w. Significant regional differences were observed with the highest concentrations of PFAS detected in the north central region of the GoM, where substantial industrialization and discharges from the Mississippi River occur. Compared to most wildlife and matrices analyzed globally, the PFAS profiles in Tilefish were unique as they are dominated by PFUnDA. Profile differences are hypothesized to be the result of Tilefish's distinctive lifestyle, habitat, diet, and partitioning characteristics of long-chain PFAS. Several MHCs were identified in this subset of Tilefish that could be detrimental to their health. Significant correlations between PFAS concentrations and biometric indices and MHCs were evident, however, additional research is needed to investigate the role PFAS and PFAS combined with chemical admixtures may play in inducing observed hepatic changes and other physiological effects in Tilefish. These findings give insight into the fate of PFAS at depth in aquatic ecosystems and are cause for concern regarding the health of other deep water benthic biota in GoM and other deepwater sinks for PFAS.

Exploring Differences in Baseline Characteristics among Adults Entering Integrated Residential Treatment for Co-occurring Disorders in 2013 and 2017

Little is known about patients' addiction severity, substance use, or mental health symptoms upon entering integrated treatment. This is the first study to compare baseline characteristics among cohorts of patients with co-occurring disorders entering a private integrated residential treatment program in 2013 and 2017; a period when severe and persistent mental illness diagnoses, mental health service use, and overdose deaths increased. Our sample includes 3400 patients entering private, integrated residential treatment during 2013 (n = 1535) and 2017 (n = 1865). Trained staff completed admission interviews of all participants that included the Addiction Severity Index (ASI), a semi-structured interview to evaluate the past 30-day functioning of the following domains: medical, employment, alcohol, drug, legal, family or social support systems, and psychiatric. We used a p-value of 0.05 to assess significance. With the exception of the drug composite score, the 2017 cohort scored higher than the 2013 cohort on all other composite scores. Compared to the 2013 cohort, the 2017 cohort reported more days using alcohol, cocaine, amphetamines, and engaging in polysubstance use. Conversely, the 2017 cohort reported fewer days using other prescription opioids and sedatives than the 2013 cohort. After controlling for age, the 2017 cohort reported more days of marijuana use than the 2013 cohort. The 2017 cohort reported higher rates of the following symptoms: depression, anxiety, hallucinations, and suicidal ideation. Findings underscore differences among integrated treatment patient cohorts for baseline addiction severity, substance use, or mental health symptoms.

Dynamics of Parental Opioid Use and Children's Health and Well-Being: An Integrative Systems Mapping Approach

The seemingly intractable opioid epidemic compels researchers, the media, and families to better understand the causes and effects of this complex and evolving public health crisis. The effects of this crisis on people using opioids, maternal prenatal opioid exposure, and neonatal abstinence syndrome are well-documented, but less is known about the impact of caregivers' opioid use on children's health and well-being. One challenge to understanding the effects of parental opioid use disorder (OUD) on child and adolescent outcomes is the numerous interrelated pathways in which a child's health and well-being can be impacted. To better understand these dynamic relationships, we applied a systems mapping approach to visualize complex patterns and interactions between pathways and potential leverage points for interventions. Specifically, we developed a causal loop diagram system map to elucidate the complex and interconnected relationships between parental OUD, social determinants of health at the family and socio-environmental levels, family strengths, social supports, and possible adverse impacts on children's physical and mental health and risks for future substance misuse. The goals of this research are to (1) identify factors and dynamics that contribute to the relationship between parental OUD and children's health and well-being and (2) illustrate how systems mapping as a tool can aid in understanding the complex factors and dynamics of the system(s) that influence the well-being of children and their parents or primary caregivers.

Longitudinal association between deviant peer affiliation and externalizing behavior problems by types of child maltreatment

BACKGROUND

Previous research has documented that deviant peer affiliation (DP) and externalizing behavior problems (EXT) are highly related and often co-occur. However, the directionality of the association between DP and EXT remains debatable. In addition, few studies have examined the longitudinal effects of child maltreatment types on co-development of DP and EXT overtime. Therefore, this study examined the role of child maltreatment in predicting the co-development of DP and EXT.

METHODS

DP and EXT were assessed at ages 12, 14, and 16. DP was measured using 13 items from the modified version of the Youth Risk Behavior and Monitoring the Future Survey. EXT was measured using the Child Behavior Checklist. Each type of child maltreatment (birth to age 12) was assessed using the CPS substantiated cases.

RESULTS

The results indicated that, on average, DP increased over time, whereas EXT decreased over time. In addition, the initial levels of EXT were associated with the slope of DP. Conditional parallel-process latent growth curve modeling identified that physically abused adolescents had higher initial levels of DP and showed a slower increase in DP, while those who had been emotionally abused were associated with a steeper decrease in EXT.

CONCLUSION

The findings offer several meaningful implications for practice. First, early assessment of and treatment for EXT may be helpful in preventing DP over time. In addition, practitioners could assess each type of maltreatment to tailor preventive interventions for early onset and ongoing development of DP and EXT.

A First Comprehensive Baseline of Hydrocarbon Pollution in Gulf of Mexico Fishes

Despite over seven decades of production and hundreds of oil spills per year, there were no comprehensive baselines for petroleum contamination in the Gulf of Mexico (GoM) prior to this study. Subsequent to the 2010 Deepwater Horizon (DWH) spill, we implemented Gulf-wide fish surveys extending over seven years (2011–2018). A total of 2,503 fishes, comprised of 91 species, were sampled from 359 locations and evaluated for biliary polycyclic aromatic hydrocarbon (PAH) concentrations. The northern GoM had significantly higher total biliary PAH concentrations than the West Florida Shelf, and coastal regions off Mexico and Cuba. The highest concentrations of biliary PAH metabolites occurred in Yellowfin Tuna (Thunnus albacares), Golden Tilefish (Lopholatilus chamaeleonticeps), and Red Drum (Sciaenops ocellatus). Conversely, biliary PAH concentrations were relatively low for most other species including economically important snappers and groupers. While oil contamination in most demersal species in the north central GoM declined in the first few years following DWH, more recent increases in exposure to PAHs in some species suggest a complex interaction between multiple input sources and possible re-suspension or bioturbation of oil-contaminated sediments. This study provides the most comprehensive baselines of PAH exposure in fishes ever conducted for a large marine ecosystem.

Spatial contrasts in hepatic and biliary PAHs in Tilefish (Lopholatilus chamaeleonticeps) throughout the Gulf of Mexico, with comparison to the Northwest Atlantic

A multinational demersal longline survey was conducted on the Gulf of Mexico continental shelf over the years 2015 and 2016 to generate a Gulf-wide baseline of polycyclic aromatic hydrocarbon (PAH) concentrations in demersal fishes. Tilefish (Lopholatilus chamaeleonticeps) were sampled in all regions of the Gulf of Mexico for biometrics, bile, and liver. Tilefish liver was also obtained from surveys in the northwest Atlantic Ocean for comparison. Liver tissues (n = 305) were analyzed for PAHs and select alkylated homologs using QuEChERS extractions and gas chromatography tandem mass spectrometry. Bile samples (n = 225) were analyzed for biliary PAH metabolites using high-performance liquid chromatography with fluorescence detection. Spatial comparisons indicate the highest levels of PAH exposure and hepatic accumulation in the north central Gulf of Mexico, with decreasing concentrations moving from the north central Gulf counterclockwise, and an increase on the Yucatán Shelf. Hepatic PAH concentrations were similar between the Gulf of Mexico and the northwest Atlantic, however, Tilefish from the northwest Atlantic had higher concentrations and more frequent detection of carcinogenic high molecular weight PAHs. Overall, results demonstrate that PAH pollution was ubiquitous within the study regions, with recent exposure and hepatic accumulation observed in Tilefish from both the Gulf of Mexico and northwest Atlantic.

Child Maltreatment, Fathers, and Adolescent Alcohol and Marijuana Use Trajectories

Background: Little is known about heterogeneity in developmental trajectories of alcohol and marijuana use among at-risk youth. Objective: This study aims to examine how child maltreatment and father structural factors at different stages in the life course are associated with different patterns of alcohol and marijuana use trajectories. Methods: A sample of youth (N = 903) were drawn from the Longitudinal Studies of Child Abuse and Neglect (LONGSCAN). Latent class growth analysis was employed to assess heterogeneity in patterns of adolescent alcohol and marijuana use. In addition, binary logistic regression analysis was performed to examine child maltreatment and father structural factors across different developmental stages as predictors of membership in the identified alcohol and marijuana use trajectory classes. Results: For both alcohol and marijuana use, two distinct latent classes were identified: stable no/low alcohol use (74%) vs. increasing alcohol use (26%); stable no/low marijuana use (85%) vs. increasing marijuana use (15%). Emotional abuse during early childhood and physical abuse during adolescence predicted membership in the increasing alcohol use and the increasing marijuana use classes. The presence of father in the home during early childhood was associated with lower likelihood of being in the increasing alcohol use class. Conclusions: Our findings highlight the importance of understanding the etiology of adolescent substance use through a developmental lens. Screening of exposure to child maltreatment across different developmental stages and interventions promoting father engagement during early childhood might help mitigate the risk of adolescent alcohol and marijuana use.

Associations Between Chronic Exposure to Polycyclic Aromatic Hydrocarbons and Health Indices in Gulf of Mexico Tilefish (Lopholatilus chamaeleonticeps) Post Deepwater Horizon

A time series of polycyclic aromatic hydrocarbon (PAH) data was collected for Gulf of Mexico demersal fishes in the years following the Deepwater Horizon oil spill (2012-2017). Tilefish (Lopholatilus chamaeleonticeps) were sampled via demersal longline at repeat stations in the northern Gulf of Mexico in 2012 to 2015 and 2017. Bile samples (n = 256) were analyzed via high-performance liquid chromatography with fluorescence detection for PAH metabolites as a biomarker of exposure to PAHs. Liver tissues (n = 230) were analyzed for accumulation of PAHs and alkylated homologs via quick, easy, cheap, effective, rugged, and safe (QuEChERS) extractions and gas chromatography-tandem mass spectrometry quantification. Over the 6-yr time series, exposure to petrogenic PAHs increased by an average of 178%, correlating with an average 22% decline in Fulton's condition factor. The decline in Fulton's condition factor was positively correlated with a 53% decline in percentage of liver lipid. There was no accumulation of PAHs in liver tissue over time. Together, these results suggest that increasing and chronic PAH exposure and metabolism may be taxing the energy budgets of tilefish, particularly adult females, with potentially negative impacts on fitness. Environ Toxicol Chem 2019;38:2659-2671. © 2019 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals, Inc. on behalf of SETAC.

A comparison of 2013 and 2017 baseline characteristics among treatment-seeking patients who used opioids with co-occurring disorders

The opioid epidemic is a public health crisis that has captured the attention of the media and political leaders, but how much do we know about its implications for substance use disorder treatment providers? This study is the first to investigate the differing baseline characteristics among patients with co-occurring disorders who used opioids and entered residential treatment in 2013 and 2017. Our sample consisted of 1413 unique adults who reported using opioids upon admission to integrated residential treatment for co-occurring substance use and mental health disorders during 2013 (n = 718) and 2017 (n = 695). Opioid use was defined as self-reported use of heroin or illicit use of prescription opioids, including methadone, during the month prior to admission into the treatment program. All study participants completed an admission interview that included the Addiction Severity Index (ASI). The 2017 cohort demonstrated higher severity than the 2013 cohort on the employment, psychiatric, and alcohol and drug ASI composite scores. A comparison of days per month that the cohorts used various substances also reveals this trend, with the following comparisons listing the 2017 cohort data first, and the 2013 cohort data second: (1) alcohol (8.6 days vs. 7.0 days); (2) cocaine (4.1 days vs. 2.2 days); (3) amphetamines (6.2 days vs. 3.6 days); and (4) polysubstance use in one day (16.6 days vs. 11.6 days). The 2017 cohort was also intoxicated from alcohol more days per month (7.2 days vs. 5.1 days). However, the 2017 cohort reported fewer days using prescription opioids (9.9 days vs. 12.4 days). A higher proportion of the 2017 cohort reported (1) depression (74% vs. 68%); (2) anxiety (88% vs. 84%); (3) hallucinations (14% vs 8%); and (4) and suicidal ideation (22% vs. 17%).

A Response to "The Legacy of the Witch-Hunt Narrative"

The article provides an overview of and commentary on the last chapter of Cheit's book, The Witch-Hunt Narrative: Politics, Psychology and the Sexual Abuse of Children. The chapter is divided into two sections called "Recent Developments" and "The Legacy of the Witch-Hunt Narrative." We respond to the key assertions in each of those sections, providing discussion points of agreement and disagreement with Cheit, and note some areas Cheit does not cover, including important advances in the aftermath of the witch-hunt narrative (WHN). The article takes the position that there is cause for optimism with these advances in systems responses, child forensic interviewing research, and multidisciplinary team and training approaches; some of these advances are related to the WHN. The conclusion warns of the need to be vigilant about continuing Cheit's work, we suggest this could take place in six key areas: (a) enhanced teacher training, (b) improved court responses to child sexual abuse (CSA) victims, (c) expanded use of Extended Forensic Interviews so that the complex cases (children with disabilities, children from multi problem households) might be thoroughly considered for prosecution, (d) broadened focus on CSA validation, recovery, and prevention, (e) engaged multistate research on the actual occurrence of day care CSA allegations, and (f) expanded efforts to educate the public and potential jury pools about the nuances of CSA prosecution, and the illusion of toughness in how we respond to convicted offenders. Cheit's detailed research enables us to see where we came from, and what else needs to be done to understand the legacy of the WHN.

The Influence of Supervisory Neglect on Subtypes of Emerging Adult Substance Use After Controlling for Familial Factors, Relationship Status, and Individual Traits

BACKGROUND

This study is the first to explore how child supervisory neglect influences patterns of substance use among young adults. This study investigated patterns of substance use among males and females, 18 to 24 years old, after controlling for adolescent parental drinking, living with parents, relationship status, delinquency, and depression.

METHODS

The study sample (N=10,618) included individuals who participated in Waves I (1994-1995) and III (2001-2002) of the National Longitudinal Study of Adolescent Health (Add Health). The study used latent class analysis to ascertain how patterns of substance use emerged as distinct classes.

RESULTS

For both males and females, we identified the following 4 classes of substance use: (1) heavy polysubstance use, (2) moderate polysubstance use, (3) alcohol and marijuana, and (4) low-use substance use patterns. Multinomial logistic regression indicated that, for both males and females 18 to 24 years old, experiencing supervisory neglect, being depressed, being single, and engaging in adolescent delinquency serve as risk factors for heavy polysubstance use class membership. Conversely, being black or Hispanic lowered the likelihood of polysubstance use for males and females. For females only, living with parents served as a protective factor that reduced the risk of membership in heavy polysubstance use, moderate polysubstance use, and alcohol and marijuana classes. For males only, being less educated increased the risk of heavy polysubstance use class membership.

CONCLUSIONS

Results from this exploratory study underscore the enduring effect of supervisory neglect on substance use among male and female young adults. Future studies should explore whether these relationships hold over time.

Problem Internet Overuse Behaviors in College Students: Readiness-to-Change and Receptivity to Treatment

This mixed methods study explores college students' readiness-to-change and receptivity to treatment for problem Internet overuse behaviors. Focus groups were conducted with 27 college students who self-identified as Internet over-users, and had experienced biopsychosocial problems related to Internet overuse. Participants completed standardized questionnaires assessing their Internet use and sociodemographic forms. Focus groups explored readiness to change problem Internet overuse behaviors and receptivity to treatment. Similar to college students with other addictive behaviors, students with problem Internet overuse fall along a continuum vis-à-vis readiness-to-change their behaviors. Over half of the participants were receptive to treatment for their problem Internet overuse behaviors.

Diagnostic Criteria for Problematic Internet Use among U.S. University Students: A Mixed-Methods Evaluation

Empirical studies have identified increasing rates of problematic Internet use worldwide and a host of related negative consequences. However, researchers disagree as to whether problematic Internet use is a subtype of behavioral addiction. Thus, there are not yet widely accepted and validated diagnostic criteria for problematic Internet use. To address this gap, we used mixed-methods to examine the extent to which signs and symptoms of problematic Internet use mirror DSM-5 diagnostic criteria for substance use disorder, gambling disorder, and Internet gaming disorder. A total of 27 university students, who self-identified as intensive Internet users and who reported Internet-use-associated health and/or psychosocial problems were recruited. Students completed two measures that assess problematic Internet use (Young’s Diagnostic Questionnaire and the Compulsive Internet Use Scale) and participated in focus groups exploring their experiences with problematic Internet use. Results of standardized measures and focus group discussions indicated substantial overlap between students’ experiences of problematic Internet use and the signs and symptoms reflected in the DSM-5 criteria for substance use disorder, gambling disorder, and Internet gaming disorder. These signs and symptoms included: a) use Internet longer than intended, b) preoccupation with the Internet, c) withdrawal symptoms when unable to access the Internet, d) unsuccessful attempts to stop or reduce Internet use, e) craving, f) loss of interest in hobbies or activities other than the Internet, g) excessive Internet use despite the knowledge of related problems, g) use of the Internet to escape or relieve a negative mood, and h) lying about Internet use. Tolerance, withdrawal symptoms, and recurrent Internet use in hazardous situations were uniquely manifested in the context of problematic Internet use. Implications for research and practice are discussed.

The Effect of Childhood Supervisory Neglect on Emerging Adults' Drinking

This study investigated the effect of childhood supervisory neglect on emerging adults' drinking. Child supervisory neglect is the most common form of child maltreatment in the United States, but few studies explore supervisory neglect separate from other forms of maltreatment among emerging adults, 18-25 years old. The study sample included (n = 11,117) emerging adults, 18-25 years old who participated in Waves I and III of the National Longitudinal Study of Adolescent Health (Add Health). We conducted separate analyses for male and female emerging adults, because they have different rates of alcohol consumption and alcohol risk behaviors. Our study used latent class analysis to understand how patterns of alcohol risk behaviors clustered together. For males, we found the following four classes: (1) multiple-risk drinkers, (2) moderate-risk drinkers, (3) binge-drinkers, and (4) low-risk drinkers or abstainers. For females, we found the following three classes: (1) multiple-risk drinkers, (2) moderate-risk drinkers, and (3) low-risk drinkers or abstainers. For both males and females, supervisory neglect increased the odds of membership in the multiple-risk drinkers' class compared to the low-risk drinkers or abstainers' class. Single males who did not live with their parents, and who were white had increased odds of being in the multiple-risk drinkers. For females, being more educated, or in a serious romantic relationship increased the odds of membership in the multiple-risk drinkers' class. Practitioners should ask about histories of supervisory neglect among emerging adults who engage in alcohol risk behaviors.

What Social Bonds have the Greatest Influence on Patterns of Substance Use among Child-Welfare-Involved Youth?

Child-welfare-involved youth may lack protective social bonds that could reduce their risk of substance use. We investigated whether caregiver, school, or peer bonds predict distinct patterns of substance use among child-welfare-involved youth. The sample included 720 participants in the National Survey of Child and Adolescent Well-Being II. Latent class analysis (LCA) and the three-step approach to incorporate indicator variables onto the latent classes were used. We found the following classes: (1) severe polysubstance use; (2) moderate polysubstance use; and (3) low use. Youth bonded to primary caregivers were less likely to be severe polysubstance drug users, but caregiver bonds did not protect against moderate polysubstance use. School bonds protected against severe polysubstance and moderate polysubstance. Youth bonded to deviant peers were more likely to be in the severe polysubstance use and moderate polysubstance use classes. Interventions targeting child-welfare-involved youth need to account for social bonds' effect on substance use.

Patterns of Inhalant Use among Incarcerated Youth

Inhalant use is especially prevalent among antisocial youth and can have serious health consequences. However, the extant literature has not investigated how use of various inhalants may co-occur among incarcerated youth. This study begins to address this gap in the literature by using latent class analyses to form distinct typologies of inhalant use. Study participants were residents (N = 723) of 27 Missouri Division of Youth Services facilities. Interviews assessed psychiatric symptoms, antisocial traits, delinquency, trauma, suicidality, and substance use behaviors. The mean age of the mostly male, ethnically diverse sample was 15.5 (S.D. = 1.2) years old. The study revealed the following classes of inhalant use: (1) severe polyinhalant use; (2) moderate polyinhalant use; (3) gas and permanent marker use; and (4) low-use. Compared to the low-use class, members of the severe polyinhalant use class had experienced more than double the rate of head injuries, the highest rates of traumatic experiences, and the highest rates of mental illness diagnoses. The gas and markers class had the highest rate of reporting hearing voices, followed by the severe polyinhalant use class, and the moderate polyinhalant use class. Results of this study underscore the need to address the high rate of head injuries and mental health diagnoses that contribute to severe polyinhalant use.

Correlates of optimal behavior among child welfare-involved children: Perceived school peer connectedness, activity participation, social skills, and peer affiliation

Understanding the association between children's behaviors and their perceptions regarding the quality of school friendships is useful for intervention strategies focusing on the interpersonal networks of children involved with the child welfare system. Rarely are measures of the strength of peer relationships assessed as a protective factor for maltreated children in the context of understanding their behaviors. This research investigates the link between these youth's expressed relational experiences and nonproblematic behavior. Analyses were conducted on 1,054 children (ages 11-17) from the National Survey of Child and Adolescent Well-Being II (NSCAW II) dataset. Utilizing a factored measure of perceived school friend connectedness, children's behaviors were predicted using Generalized Ordered Logistic regression analyses. Results demonstrated stronger school friend connectedness is a protective factor in that, children who perceive strong peer connections at school are more likely to classify below the problem behavior threshold than those with weaker peer connections. Further, children with increased social skills; fewer deviant peer affiliations; and those who take responsibility in part-time jobs and chores are more likely to display normative behaviors. Compared with all other types of maltreatment, physically abused children are significantly less likely to display behaviors below the problem range. Moreover, physical abuse has a negative impact on the protective nature of strong peer connections. Attention should be given to supporting children's perceived positive friendships, developing social skills, and encouraging participation in part-time jobs (e.g., babysitting, paper routes) as protective factors associated with nonproblematic behaviors, rather than problematic behaviors. Implications for service delivery are discussed.

PAH Exposure in Gulf of Mexico Demersal Fishes, Post-Deepwater Horizon

Following the 2010 Deepwater Horizon (DWH) blowout, we surveyed offshore demersal fishes in the northern Gulf of Mexico (GoM) in 2011-2013, to assess polycyclic aromatic hydrocarbon (PAH) exposure. Biliary PAH metabolites were estimated in 271 samples of golden tilefish (Lopholatilus chamaeleonticeps), king snake eel (Ophichthus rex), and red snapper (Lutjanus campechanus), using high performance liquid chromatography with fluorescence detection. Mean concentration of naphthalene metabolites in golden tilefish (240 μg g(-1)) was significantly higher (p = 0.001) than in red snapper (61 μg g(-1)) or king snake eel (38 μg g(-1)). Biliary naphthalene metabolite concentration decreased over the study period in red snapper (58%) and king snake eel (37%), indicating likely episodic exposure, while concentrations were persistently high in golden tilefish. Naphthalene metabolite levels measured in golden tilefish are among the highest concentrations measured in fishes globally, while concentrations for red snapper and king snake eel are similar to pre-DWH levels measured in GoM species. In contrast, concentrations of benzo[a]pyrene metabolites were similar for all three species (p = 0.265, mean 220 ng g(-1)) and relatively low when compared to GoM, global data and previous oil spills. These data support previous findings that fish life history and physiology play significant roles in exposure and uptake of PAH pollution.

Formative Evaluation: A Case Study of the Illinois Birth-to-Three IV-E Waiver

Few interventions addressing early childhood trauma have adequate evidence. The Illinois Birth-to-Three Waiver is a 5-year federal project to reduce trauma and increase permanency for young children. In this article the authors describe the explorative and formative phases, including: (a) developing a well-built research question; (b) working with purveyors of evidence-supported interventions (ESIs); (c) adapting ESIs to a large public child welfare system; (d) developing fidelity measures, assessment data and outcomes; and (e) managing the challenges of implementing a randomized controlled trial. Public and private agency staff work in conjunction with university partners to merge implementation science, program evaluation, and intervention research. The project's theory of change stipulates that working with the triad of birth parent(s), foster parent(s), and focal child is critical to achieving project outcomes. The authors articulate the importance of working closely with an interdisciplinary team to achieve these outcomes, and the challenges associated with the early stages of implementation.

Adoption and guardianship: A moderated mediation analysis of predictors of post-permanency continuity

The original thinking behind permanency planning for foster children was to secure a caregiver's intention to provide a permanent home, not to guarantee it. Little is known, however, about how intentions change after permanence or what effect this change has on post-permanency continuity of care. This study examined the mediating effects of caregivers' thoughts about ending an adoption or guardianship, and how this mechanism may be contingent on primordial and bureaucratic factors that child welfare agencies rely on to ensure family continuity after legal permanence. In 2006, a sample of 346 Illinois caregivers who finalized an adoption or guardianship between 1998 and 2002 completed surveys about child behavior problems, the adequacy of financial assistance, and thoughts about maintaining the permanency relationship. Responses were linked to administrative data that tracked continuity of care through 2012. Simple mediation and moderated mediation hypotheses of the effects of caregiver thoughts on post-permanency continuity were tested. At last observation, 8% of caregivers were no longer living with the child or stopped receiving subsidies on the child's behalf. Thoughts expressed at survey time about ending the permanency relationship mediated the effect of child behavior problems on post-permanency discontinuity rates. This indirect effect was more pronounced among distantly related kin, lone caregivers, and caregivers who felt the subsidy was inadequate to cover their expenses. Our findings suggest that post-permanency services should target a narrow segment of caregivers who express weakened permanency commitments that arise from the challenges of parenting a child with multiple behavioral problems.

Do physical abuse, depression, and parental substance use influence patterns of substance use among child welfare involved youth? Substance use misuse

To date studies have not explored patterns of substance use exclusively among youth in the child welfare system. Consequently, little is known about polysubstance use among child welfare-involved youth. This study aimed to explore whether physical abuse, parental substance use, depression, and demographic characteristics predict distinct patterns of substance use among child welfare-involved youth using latent class analysis (LCA). The sample included 822 11-17 year olds who participated in the National Survey of Child and Adolescent Well-being (NSCAW II) study between March 2008 and September 2009. We found the following three classes: (1) polysubstance use, (2) alcohol and marijuana use, and (3) low use. Older youth and youth who experienced physical abuse were at greater risk of being in the polysubstance use class, while living with a biological parent reduced the likelihood of polysubstance use class membership. Youth in the alcohol and marijuana use class were more likely to be older and depressed. Results from this study illuminate important targets for interventions.

Maltreatment type and behaviors: does listening matter?

This article presents an exploratory assessment of whether children's perceptions of caseworker support (e.g. feeling listened to) moderates the relationship between the type of maltreatment and problematic behaviors. Relying on data collected for the National Survey of Child and Adolescent Well-Being (NSCAW I), this research measures how often children felt listened to by their caseworkers and the effect on the relationship between two types of maltreatment (e.g. physical abuse and neglect) and problematic child behaviors. Results indicate that whereas children reported feeling listened to most of the time, there are significant differences in the probabilities of problematic behavior scores between physically abused and neglected children according to how often they felt listened to. With the exception of those children who felt listened to all of the time, physically abused children have a higher probability of problematic behaviors than neglected children. Comparisons between the two maltreatment types indicate a greater impact of listening on physically abused children across the continuum of feeling listened to (e.g. never to all of the time), than for neglected children, except for at the highest level of listening, as results indicate a small, but significant difference indicating neglected children are more positively impacted by listening than physically abused kids. Implications for practice are that children's perceptions of support from caseworkers may influence behavioral outcomes differently according to maltreatment type. Additionally, these findings encourage the inclusion of children's perspectives regarding the relationships they have with caseworkers.

Do incest, depression, parental drinking, serious romantic relationships, and living with parents influence patterns of substance use during emerging adulthood?

This study examined how incest, depression, parental drinking, relationship status, and living with parents affect patterns of substance use among emerging adults, 18 to 25 years old. The study sample included (n = 11,546) individuals who participated in Waves I, II, and III of the National Longitudinal Study of Adolescent Health (Add Health). The study used separate latent class analysis for males and females to determine how patterns of substance use clustered together. The study identified the following three classes of substance use: heavy, moderate, and normative substance use patterns. Multinomial logistic regression indicated that, for females only, incest histories also nearly doubled the risk of heavy-use class membership. In addition, experiencing depression, being single, and not living with parents serve as risk factors for males and females in the heavy-use group. Conversely, being Black, Hispanic, or living with parents lowered the likelihood of being in the group with the most substance use behaviors (i.e., heavy use). Findings highlight the need for interventions that target depression and female survivors of incest among emerging adults.

Typologies of substance use and illegal behaviors: A comparison of emerging adults with histories of foster care and the general population

This study used latent class analysis (LCA) to explore whether patterns of substance use and illegal behaviors among emerging adults, 18 to 28 years old, differ depending on whether they have a prior history in foster care. The study sample, consisting of 316 respondents who had previously been in foster care and 14,301 respondents without a foster care history, was drawn from the third wave of the National Longitudinal Study of Adolescent Health. A multiple-group LCA compared former foster youth to their peers in the general population. The following four classes were identified: illegal behaviors, substance use, illegal behaviors with problematic substance use and normative behaviors. Most of the differences between the groups were not statistically significant. However, within the illegal behavior class former foster youth were less likely to have bought, sold, or held stolen goods; injured someone in a fight so that she or he needed medical attention; to have sold drugs; and to have been drunk at school or work. Additionally, in the illegal behaviors with problematic substance use class emerging adults in the general population were more likely to have used cocaine. Within the normative behaviors class, former foster youth were more likely to be current smokers, and to have injured someone in a fight so that he or she required medical attention. Within the substance use class, emerging adults from the general population were more likely to have taken place in a fight where one group fought another. Additional statistically significant, but very small differences were also identified.

Are Nonprofit Density and Nonprofit Expenditures Related to Youth Deviance?

This study explores whether neighborhoods with greater nonprofit density (nonprofits per mile) and/or larger nonprofit expenditures (nonprofit expenditures per 10,000 people) interact with social control to experience lower levels of adolescent deviancy. Data include cross-sectional surveys of 1,541 youth. The data are analyzed using Hierarchical Linear Modeling (HLM). The dependent variable is a measure of deviance that is the sum of ten items, which assess deviant behaviors. For analysis the square root of this measure is used to adjust for negatively skewed data. The sample was drawn through a two stage-geostatistical sampling procedure, with the final sample including 50 zip codes throughout California. The study finds that adolescents' deviance is not associated with an interaction between social control and either nonprofit density or nonprofit expenditures. However, the analysis found strong positive associations between being male, being older, having higher levels of mean social control and the square root of deviance.

Renal hypertension prevents run training modification of cardiomyocyte diastolic Ca2+ regulation in male rats

The combined effects of endurance run training and renal hypertension on cytosolic Ca2+ concentration ([Ca2+]c) dynamics and Na+-dependent Ca2+ regulation in rat left ventricular cardiomyocytes were examined. Male Fischer 344 rats underwent stenosis of the left renal artery [hypertensive (Ht), n = 18] or a sham operation [normotensive (Nt), n = 20]. One-half of the rats from each group were treadmill trained for >16 wk. Cardiomyocyte fura 2 fluorescence ratio transients were recorded for 7 min during electrical pacing at 0.5 Hz, 2 mM extracellular Ca2+ concentration, and 29°C. The rate of [Ca2+]c decline was not changed by run training in the Nt group but was reduced in the Ht group. At 7 min, cardiomyocytes were exposed to 10 mM caffeine in the absence of Na+ and Ca2+, which triggered sarcoplasmic reticular Ca2+ release and suppressed Ca2+efflux via Na+/Ca2+ exchanger. External Na+ was then added, and Na+-dependent Ca2+ efflux rate was recorded. Treadmill training significantly enhanced Na+-dependent Ca2+efflux rate under these conditions in the Nt group but not in the Ht group. These data provide evidence that renal hypertension prevents the normal run training-induced modifications in diastolic [Ca2+]c regulation mechanisms, including Na+/Ca2+ exchanger.

A mathematical model of cardiocyte Ca(2+) dynamics with a novel representation of sarcoplasmic reticular Ca(2+) control

Cardiac contraction and relaxation dynamics result from a set of simultaneously interacting Ca(2+) regulatory mechanisms. In this study, cardiocyte Ca(2+) dynamics were modeled using a set of six differential equations that were based on theories, equations, and parameters described in previous studies. Among the unique features of the model was the inclusion of bidirectional modulatory interplay between the sarcoplasmic reticular Ca(2+) release channel (SRRC) and calsequestrin (CSQ) in the SR lumen, where CSQ acted as a dynamic rather than simple Ca(2+) buffer, and acted as a Ca(2+) sensor in the SR lumen as well. The inclusion of this control mechanism was central in overcoming a number of assumptions that would otherwise have to be made about SRRC kinetics, SR Ca(2+) release rates, and SR Ca(2+) release termination when the SR lumen is assumed to act as a simple, buffered Ca(2+) sink. The model was sufficient to reproduce a graded Ca(2+)-induced Ca(2+) release (CICR) response, CICR with high gain, and a system with reasonable stability. As constructed, the model successfully replicated the results of several previously published experiments that dealt with the Ca(2+) dependence of the SRRC (, J. Gen. Physiol. 85:247-289), the refractoriness of the SRRC (, Am. J. Physiol. 270:C148-C159), the SR Ca(2+) load dependence of SR Ca(2+) release (, Am. J. Physiol. 268:C1313-C1329;, J. Biol. Chem. 267:20850-20856), SR Ca(2+) leak (, J. Physiol. (Lond.). 474:463-471;, Biophys. J. 68:2015-2022), SR Ca(2+) load regulation by leak and uptake (, J. Gen. Physiol. 111:491-504), the effect of Ca(2+) trigger duration on SR Ca(2+) release (, Am. J. Physiol. 258:C944-C954), the apparent relationship that exists between sarcoplasmic and sarcoplasmic reticular calcium concentrations (, Biophys. J. 73:1524-1531), and a variety of contraction frequency-dependent alterations in sarcoplasmic [Ca(2+)] dynamics that are normally observed in the laboratory, including rest potentiation, a negative frequency-[Ca(2+)] relationship, and extrasystolic potentiation. Furthermore, under the condition of a simulated Ca(2+) overload, an alternans-like state was produced. In summary, the current model of cardiocyte Ca(2+) dynamics provides an integrated theoretical framework of fundamental cellular Ca(2+) regulatory processes that is sufficient to predict a broad array of observable experimental outcomes.

Chronic run training suppresses alpha-adrenergic response of rat cardiomyocytes and isovolumic left ventricle

The effects of endurance run training on alpha-adrenergic responsiveness of rat left ventricle (LV) were examined in cardiomyocytes and isovolumic LV. Female Sprague-Dawley rats were sedentary (Sed) or trained (Tr) for >20 wk by treadmill running. Cardiomyocyte shortening and fura 2 fluorescence ratio were recorded before and during 5-min exposure to 5 microM phenylephrine (PE) while paced at 0.5 Hz in 2 mM extracellular Ca2+ concentration at 29 degrees C. Cardiomyocyte shortening and shortening velocity increased with PE, and these effects were more pronounced in the Sed group. The rate of cytosolic Ca2+ concentration removal was reduced by PE in the Sed cardiomyocytes, but was unaffected in the Tr. Isovolumic LV pressure was recorded immediately before and during 5-min perfusion with 5 microM PE during pacing at 280 beats/min and 37 degrees C, and positive inotropy due to PE was more pronounced in the Sed than in the Tr. These data demonstrated that the effects of alpha-adrenergic stimulation on myocardial positive inotropy and calcium regulation were reduced in this rat model of run training at both the cellular and whole organ levels.

Effects of chronic run training on Na+-dependent Ca2+ efflux from rat left ventricular myocytes

The effects of endurance run training on Na+-dependent Ca2+ regulation in rat left ventricular myocytes were examined. Myocytes were isolated from sedentary and trained rats and loaded with fura 2. Contractile dynamics and fluorescence ratio transients were recorded during electrical pacing at 0.5 Hz, 2 mM extracellular Ca2+ concentration, and 29 degreesC. Resting and peak cytosolic Ca2+ concentration ([Ca2+]c) did not change with exercise training. However, resting and peak [Ca2+]c increased significantly in both groups during 5 min of continuous pacing, although diastolic [Ca2+]c in the trained group was less susceptible to this elevation of intracellular Ca2+. Run training also significantly reduced the rate of [Ca2+]c decay during relaxation. Myocytes were then exposed to 10 mM caffeine in the absence of external Na+ or Ca2+ to trigger sarcoplasmic reticular Ca2+ release and to suppress cellular Ca2+ efflux. This maneuver elicited an elevated steady-state [Ca2+]c. External Na+ was then added, and the rate of [Ca2+]c clearance was determined. Run training significantly reduced the rate of Na+-dependent clearance of [Ca2+]c during the caffeine-induced contractures. These data demonstrate that the removal of cytosolic Ca2+ was depressed with exercise training under these experimental conditions and may be specifically reflective of a training-induced decrease in the rate of cytosolic Ca2+ removal via Na+/Ca2+ exchange and/or in the amount of Ca2+ moved across the sarcolemma during a contraction.

Shortening and [Ca2+] dynamics of left ventricular myocytes isolated from exercise-trained rats

The effects of run endurance training and fura 2 loading on the contractile function and Ca2+ regulation of rat left ventricular myocytes were examined. In myocytes not loaded with fura 2, the maximal extent of myocyte shortening was reduced with training under our pacing conditions [0.5 Hz at 2.0 and 0.75 mM external Ca2+ concentration ([Ca2+]o)], although training had no effect on the temporal characteristics. The "light" loading of myocytes with fura 2 markedly suppressed (approximately 50%) maximal shortening in the sedentary and trained groups, although the temporal characteristics of myocyte shortening were significantly prolonged in the trained group. No discernible differences in the dynamic characteristics of the intracellular Ca2+ concentration ([Ca2+]) transient were detected at 2.0 mM [Ca2+]o, although peak [Ca2+] and rate of [Ca2+] rise during caffeine contracture were greater in the trained state at 0.75 mM [Ca2+]o. We conclude that training induced a diminished myocyte contractile function under the conditions studied here and a more effective coupling of inward Ca2+ current to sarcoplasmic reticulum Ca2+ release at low [Ca2+]o, and that fura 2 and its loading vehicle DMSO significantly alter the intrinsic characteristics of myocyte contractile function and Ca2+ regulation.

Four new mutations in the apolipoprotein B gene causing hypobetalipoproteinemia, including two different frameshift mutations that yield truncated apolipoprotein B proteins of identical length

Familial hypobetalipoproteinemia can be caused by mutations in the apolipoprotein (apo)B gene that interfere with the translation of a full-length apoB molecule. Frequently, a truncated apoB molecule can be detected in the plasma lipoproteins of affected subjects. In this report, we characterize four different apoB gene mutations causing hypobetalipoproteinemia that are associated with the synthesis of truncated apoB proteins. Two of the mutations are nonsense mutations caused by single nucleotide substitutions; these mutations are associated with the production of apoB-32.5 (1473 amino acids) and apoB-82 (3733 amino acids). The other two mutations are single nucleotide deletions (of apoB cDNA nucleotides 7295 and 7359, respectively). The altered reading frames created by these different frameshift mutations terminated with the same stop codon, and both therefore yielded a truncated protein of identical size: apoB-52.8 (2395 amino acids). The two apoB-52.8 proteins differ, however, in the number of novel carboxyl-terminal amino acids introduced by the frameshift. The buoyant density of lipoproteins containing the truncated apoBs was inversely related to the length of the truncated apoB. ApoB-32.5 was present only in high density lipoproteins (HDL) and the d > 1.21 g/ml fraction, whereas apoB-82 was present almost exclusively in very low density lipoproteins (VLDL). ApoB-52.8 was present primarily in VLDL, intermediate density lipoproteins (IDL), and low density lipoproteins (LDL); trace amounts were observed in the HDL.

Resistive Liquid-Vapor Surface Sensors for Liquid Nitrogen and Hydrogen

Ten resistance thermometers were tested as point sensors for detecting the liquid-vapor interface in liquid nitrogen and liquid hydrogen. Test results showed that most could be made to detect the liquid surface and lead orientation can be important. A silicon resistive sensor had the fastest response and produced the greatest signal change.

Estimation of mechanical properties of cortical bone by computed tomography

It is difficult to assess from conventional x-rays the amount of loading that a bone can tolerate. The question therefore was asked whether the mechanical properties of cortical bone could be estimated by using a computed tomography (CT) system typically employed in the clinical setting. In vitro cross sectional diaphyseal scans of adult human tibiae were made using a GE 9800 scanner and linear attenuation coefficients determined in several regions of the central cross sections. Samples from the mid-diaphyses of these tibiae were harvested, tested in three-point bending to failure, and mechanical properties as well as density and ash fraction determined. The respective relationships between CT measurements, mechanical properties, and physical properties were calculated using regression analysis. In addition, a solid calibration phantom (tricalciumphosphate) was scanned to evaluate the variability of CT measurements. The physical parameters measured in this study were found to be comparable with data from other authors but correlations were moderate to weak. Linear regression revealed the following correlation coefficients with CT data: r = 0.55 (Young's modulus), r = 0.50 (strength), r = 0.65 (apparent density) and r = 0.46 (ash fraction). The correlation coefficients of these regressions for both linear and power fits were not significantly different. A high linear correlation (r = 0.99) was found between the chamber densities and the measured attenuation coefficients, but accuracy varied between 2 and 6%. The small range of specimen mechanical properties as well as the limitations inherent with the methods employed may explain these results. We conclude that clinical equipment as used in this study is not sufficient to accurately estimate the mechanical properties of cortical bone.

Familial hypobetalipoproteinemia caused by a mutation in the apolipoprotein B gene that results in a truncated species of apolipoprotein B (B-31). A unique mutation that helps to define the portion of the apolipoprotein B molecule required for the formation of buoyant, triglyceride-rich lipoproteins

Apolipoprotein B-100 has a crucial structural role in the formation of VLDL and LDL. Familial hypobetalipoproteinemia, a syndrome in which the concentration of LDL cholesterol in plasma is abnormally low, can be caused by mutations in the apo B gene that prevent the translation of a full-length apo B-100 molecule. Prior studies have revealed that truncated species of apo B [e.g., apo B-37 (1728 amino acids), apo B-46 (2057 amino acids)] can occasionally be identified in the plasma of subjects with familial hypobetalipoproteinemia; in each of these cases, the truncated apo B species has been a prominent protein component of VLDL. In this report, we describe a kindred with hypobetalipoproteinemia in which the plasma of four affected heterozygotes contained a unique truncated apo B species, apo B-31. Apolipoprotein B-31 is caused by the deletion of a single nucleotide in the apo B gene, and it is predicted to contain 1425 amino acids. Apolipoprotein B-31 is the shortest of the mutant apo B species to be identified in the plasma of a subject with hypobetalipoproteinemia. In contrast to longer truncated apo B species, apo B-31 was undetectable in the VLDL and the LDL; however, it was present in the HDL fraction and the lipoprotein-deficient fraction of plasma. The density distribution of apo B-31 in the plasma suggests the possibility that the amino-terminal 1425 amino acids of apo B-100 are sufficient to permit the formation and secretion of small, dense lipoproteins but are inadequate to support the formation of the more lipid-rich VLDL and LDL particles.

Tracheal volume deformation in a developmental rabbit model

Alterations in tracheal volume were evaluated in a developmental in vivo rabbit model during and following the application of continuous positive pressure (CPP). Sequential volume changes were recorded during 60 min of CPP to a bypassed tracheal segment. The distal trachea was utilized for spontaneous ventilation. CPP of 10 cm H2O was applied to three developmental groups: group I, 5 term newborn pups; group II, 5, 7-day-old pups, and group III, 5 adult female rabbits of 18 +/- 6 months old. Changes in tracheal volume were measured by a micropipette system. Following 60 min of CPP, tracheal volumes increased (p less than 0.01) by 39.8% in group I; 36.1% in group II and 5.1% in group III. During a recovery period (60 min), return towards initial resting volume was observed in all groups, though maximal persistent volume deformation was observed in groups I and II. Thus, these data indicate tracheal barotrauma in the form of persistent dimensional deformation at early stages of development in an in vivo rabbit model.

Controlling absenteeism can help curb hospitals' costs

Absenteeism involves costs associated with sick pay, overtime pay, decreased employee productivity, and less effective patient care. Hospital management and supervisors must minimize absenteeism and its costs by thoroughly recording and evaluating employees' attendance patterns, counseling and disciplining employees when necessary, and applying policies on attendance with consistency.

Monozygotic twins with Klinefelter's syndrome discordant for systemic lupus erythematosus and symptomatic myasthenia gravis

Monozygotic twins with Klinefelter's syndrome were evaluated for two distinct illnesses. One subject had clinical and serologic evidence of systemic lupus erythematosus and no symptoms of muscle weakness. His identical twin had typical symptoms and laboratory evidence of myasthenia gravis. Antibodies to acetylcholine receptors were present in both subjects. These patients are discussed in relation to genetic, hormonal, and immunologic mechanisms involved in the pathogenesis of these two disorders.

Binding of thyroid hormones and their analogues to thyroxine-binding globulin in human serum

The present study was undertaken to study the binding of several thyroid hormones and structurally related compounds to human serum thyroxine-binding alpha-globulin (TBG). The source of TBG was normal human serum diluted 1:100 in 0.035 M barbital buffer, pH 7.4. In the binding assays, 125I-thyroxine, unlabeled thyroxine, and diluted serum were incubated for 20 h at 37 degrees in Plexiglas equilibrium dialysis units. Two orders of binding sites were discerned: a high affinity, low capacity binding site with an affinity constant of approximately 2.5 X 10(9) M-1, and a low affinity, very high capacity binding site with an affinity constant of less than 10(6) M-1. Studies with purified TBG, serum deficient in TBG, and purified human serum albumin indicated that the high affinity site represented binding to TBG and the low affinity site represented binging to albumin. The ability of several groups of thyroid hormone analogues to bind to TBG was then investigated. As a result of these studies, the following structural features of thyroid hormones were found to be important for optimal binding activity: (a) the L-alanine side chain conformation, (b) the presence of a 4'-hydroxyl group, (c) the presence of two substituents in the inner and outer rings (positions 3, 5, 3', and 5'), and (d) the presence of either bromines or iodines in the inner ring and iodines in the outer ring. Of lesser importance was the presence of an oxygen atom in the ether position.

Simultaneous measurement of percentage free thyroxine and triiodothyronine: comparison of equilibrium dialysis and Sephadex chromatography

An equilibrium dialysis technique was used to measure simultaneously the proportion of free thyroxine (%FT4) and free 3,4,5'-triiodothyronine (%FT3) in sera from patients with diverse states of thyroid function and abnormal levels of plasma T4-binding proteins. In general, the correlation between %FT4 and %FT3 values was excellent in the entire group of patients studied. Studies were also conducted to ascertain whether Sephadex columns could be employed to obtain simultaneous measures of plasma binding of T4 and T3. Mixtures of diluted serum and 125I-T4 and 131I-T3 were applied to columns of Sephadex in order to separate "bound" and "free" fractions. The values for percent free T4 and T3 yielded by the Sephadex process (%FT4S and %FT3S), although far greater numerically, correlated closely with 5FT4 and %FT3 measured directly by equilibrium dialysis. When %FT4 and %FT3 were multiplied by their respective serum concentrations, the resulting free T4 and free T3 indices provided good separation of hyperthyroid and hypothyroid groups from the euthyroid group. As in the dialysis method, %FT4S closely correlated with %FT3S.