Phylogeographic analysis of introns and mitochondrial DNA in the clam Ruditapes decussatus uncovers the effects of Pleistocene glaciations and endogenous barriers to gene flow.

Studies on the phylogeography of species inhabiting the Mediterranean and the nearby coasts of the NE Atlantic Ocean (MEDAT) have found subdivision and/or phylogeographic structure in one or more of the Atlantic, western Mediterranean and eastern Mediterranean basins. This structure has been explained as the result of past population fragmentation caused by Pleistocene sea level changes and current patterns of marine circulation. However, the increasing use of nuclear markers has revealed that these two factors alone are not enough to explain the phylogeographic patterns, and an additional role has been suggested for endogenous barriers to gene flow or natural selection. In this article we examined the role of these factors in Ruditapes decussatus, a commercial clam species native to MEDAT. A genetic analysis of 11 populations was carried out by examining 6 introns with a PCR-RFLP technique. We found subdivision in three regions: Atlantic (ATL), western Mediterranean plus Tunisia (WMED), and Aegean and Adriatic seas (AEGAD). Two introns (Ech and Tbp) showed alleles that were restricted to AEGAD. Sequencing a subsample of individuals for these introns indicated that AEGAD-specific alleles were separate clades, thus revealing a phylogeographic brake at the WMED-AEGAD boundary. Sequencing of the mitochondrial COI locus confirmed this phylogeographic break. Dating of the AEGAD mitochondrial haplotypes and nuclear alleles with a Bayesian MCMC method revealed that they shared common ancestors in the Pleistocene. These results can be explained in the framework of Pleistocene sea level drops and patterns of gene flow in MEDAT. An additional observation was a lack of differentiation at COI between the ATL and WMED, in sharp contrast with 4 introns that showed clear genetic subdivision. Neutrality tests did not support the hypothesis of a selective sweep acting on mtDNA to explain the contrasting levels of differentiation between mitochondrial and nuclear markers across the ATL-WMED transition, and we argue that the difference between markers is best explained by the existence of an endogenous genetic barrier, rather than by a physical barrier to larval migration alone.

Genetic and phenoptypic differentiation of zebra mussel populations colonizing Spanish river basins.

Zebra mussel populations in Ebro and Mijares Rivers (northern Spain) were analyzed to study the mechanisms by which this aquatic species deals with pollution. Variability analyses of mitochondrial cytochrome oxidase I gene and of one nuclear microsatellite were performed for ten populations from the Ebro River and one from the Mijares River. Comparison of these results with those from five additional European populations indicated that the Spanish populations constitute a homogeneous gene pool. Transcriptome analyses of gill samples from a subset of the Spanish populations showed changes on expression levels that correlated with variations in general fitness and loads of heavy metals. The less polluted upstream Ebro populations showed overexpression of mitochondrial and cell proliferation-related genes compared to the more polluted, downstream Ebro populations. Our data indicate that heavy metals were the main factors explaining these transcriptomic patterns, and that zebra mussel is resilient to pollutants (like mercury and organochlorine compounds) proved to be extremely toxic to vertebrates. We propose that zebra mussel populations sharing a common gene pool may acclimate to different levels and forms of pollution through modulations in their transcriptomic profile, although direct selection on genes showing differential expression patterns cannot be ruled out.

US cultural involvement and its association with suicidal behavior among youths in the Dominican Republic.

OBJECTIVES: We examined how US cultural involvement related to suicide attempts among youths in the Dominican Republic. METHODS: We analyzed data from a nationally representative sample of youths attending high school in the Dominican Republic (n = 8446). The outcome of interest was a suicide attempt during the past year. The US cultural involvement indicators included time spent living in the United States, number of friends who had lived in the United States, English proficiency, and use of US electronic media and language. RESULTS: Time lived in the United States, US electronic media and language, and number of friends who had lived in the United States had robust positive relationships with suicide attempts among youths residing in the Dominican Republic. CONCLUSIONS: Our results are consistent with previous research that found increased risk for suicide or suicide attempts among Latino youths with greater US cultural involvement. Our study adds to this research by finding similar results in a nonimmigrant Latin American sample. Our results also indicate that suicide attempts are a major public health problem among youths in the Dominican Republic.

Co-occurring risk behaviors among White, Black, and Hispanic US high school adolescents with suicide attempts requiring medical attention, 1999-2007: implications for future prevention initiatives.

PURPOSE: To identify subtypes of adolescent suicide attempters by examining risk profiles related to substance use, violent behavior, and depressive symptoms. To examine the relationship between these subtypes and having had two or more suicide attempts during the past year. To explore race and gender differences across subtypes of suicide attempters. METHODS: Data were combined from five nationally representative cohorts of the US Youth Risk Behavior Surveillance System (YRBSS) and focused on a subpopulation of youth who reported a suicide attempt requiring medical attention. Latent class analysis was used to identify subtypes of suicide attempters. RESULTS: Analysis yielded three classes of youth who attempted suicide, distinguishable by their levels of substance use and violent behaviors: low substance use and violent behaviors, high substance use and violent behaviors, and extreme substance use and violent behaviors. All three classes had a high propensity for endorsing depressive symptoms. The proportion of youth with two or more suicide attempts during the past year increased across subgroup of attempters with higher levels of substance use and violent behaviors. Racial and gender differences were found across subtypes of suicide attempters. CONCLUSIONS: Preventing and treating the co-occurrence of substance use and violent behaviors may serve as essential strategies for reducing suicide attempts, especially among male youth. The use of public health strategies for suicide prevention should take into account the different needs of youth at risk for suicide.

Family Relationships and Latina Teen Suicide Attempts: Reciprocity, Asymmetry, and Detachment.

Using qualitative data collected from adolescent Latinas and their parents, this article describes ways in which family relationships are organized within low-income Latino families (n = 24) with and without a daughter who attempted suicide. Based on a family-level analysis approach, we present a framework that categorizes relationships as reciprocal, asymmetrical, or detached. Clear differences are identified: Families of non-attempters primarily cluster in reciprocal families, whereas families with an adolescent suicide attempter exhibit characteristics of asymmetrical or detached families. Our results highlight the need for detailed clinical attention to family communication patterns, especially in Latino families. Clinicians may reduce the likelihood of an attempt or repeated attempts by raising mutual, reciprocal exchanges of words and support between parents and daughter.

Familism, parent-adolescent conflict, self-esteem, internalizing behaviors and suicide attempts among adolescent Latinas.

Adolescent Latinas continue to report higher levels of suicide attempts than their African-American and White peers. The phenomenon is still not understood and is theorized to be the result of the confluence of many cultural, familial, and individual level factors. In Latino cultures, belief in the importance of the family, the value known as familism, appears to protect youth's emotional and behavioral health, but parent-adolescent conflict has been found to be a risk factor for suicide attempts. The role of familism in relation to parent-adolescent conflict, self-esteem, internalizing behaviors, and suicide attempts has not been studied extensively. To address this question, we interviewed 226 adolescent Latinas, 50% of whom had histories of suicide attempts. Using path analysis, familism as a cultural asset was associated with lower levels of parent-adolescent conflict, but higher levels of internalizing behaviors, while self-esteem and internalizing behaviors mediated the relationship between parent-adolescent conflict and suicide attempts. Our findings point to the importance of family involvement in culturally competent suicide prevention and intervention programs. Reducing parent-daughter conflict and fostering closer family ties has the added effect of improving self-esteem and shrinking the likelihood of suicide attempts.

Randomized trial of a gatekeeper program for suicide prevention: 1-year impact on secondary school staff.

Gatekeeper-training programs, designed to increase identification and referral of suicidal individuals, are widespread but largely untested. A group-based randomized trial with 32 schools examined impact of Question, Persuade, Refer (QPR) training on a stratified random sample of 249 staff with 1-year average follow-up. To test QPR impact, the authors introduced and contrasted 2 models of gatekeeper-training effects in a population: gatekeeper surveillance and gatekeeper communication. Intent-to-treat analyses showed that training increased self-reported knowledge (effect size [ES] = 0.41), appraisals of efficacy (ES = 1.22), and service access (ES = 1.07). Training effects varied dramatically. Appraisals increased most for staff with lowest baseline appraisals, and suicide identification behaviors increased most for staff already communicating with students about suicide and distress. Consistent with the communication model, increased knowledge and appraisals were not sufficient to increase suicide identification behaviors. Also consistent with the communication model were results from 2,059 8th and 10th graders surveyed showing that fewer students with prior suicide attempts endorsed talking to adults about distress. Skill training for staff serving as "natural gatekeepers" plus interventions that modify students' help-seeking behaviors are recommended to supplement universal gatekeeper training.

Sexual orientation and risk factors for suicidal ideation and suicide attempts among adolescents and young adults.

Same-gender sexual orientation has been repeatedly shown to exert an independent influence on suicidal ideation and suicide attempts, suggesting that risk factors and markers may differ in relative importance between lesbian, gay, and bisexual individuals and others. Analyses of recent data from the National Longitudinal Study of Adolescent Health revealed that lesbian, gay, and bisexual respondents reported higher rates of suicidal ideation and suicide attempts than did heterosexual respondents and that drug use and depression were associated with adverse outcomes among heterosexual respondents but not among lesbian, gay, and bisexual respondents.

Screening as an approach for adolescent suicide prevention.

Among the provisions of the recently signed Garrett Lee Smith Memorial Act, Congress called for the use of screening to detect adolescents who are at risk for suicide. After a review of the literature, 17 studies involving screening instruments and programs were identified. We addressed the question: What do we know about the demonstrated effectiveness and safety of screening as a tool or program to prevent suicide among adolescents? While youth suicide screening programs offer the promise of improving identification for those who need treatment the most, further research is essential to understand how, when, where, and for whom screening programs can be used effectively and efficiently.

Stigma of persons with disabilities in Afghanistan: Examining the pathways from stereotyping to mental distress.

Despite evidence that stigma of disability is frequently reflected through stereotyping and often results in mental distress, very limited literature demonstrates the pathways through which stereotyping has an impact on mental health. Drawing from a large sample of 1449 participants interviewed between December 2012 and September 2013 from an Afghan community-based rehabilitation program, we examined the structure of stigma associated with disability in Afghanistan. Labeling and negative stereotypes, associated with a specific cause of disability, result in social exclusion that in turn impacts mental health. Using structural equation modeling with latent variables, we examined the mediation effect of stereotypes associated with disability on mental distress and anxiety. We found a mediating role of social exclusion between stereotypes and mental distress but only in the case of persons with disabilities from birth. Comparing the total effect of 'disabled at birth' and mental distress 0.195 (95% CI: 0.018-0.367) the effect size of this mediation effect was 0.293 (95% CI: 0.173-0.415). There was no significant direct effect between 'disabled at birth' and mental distress once mediation effect was accounted for in our model. These findings suggest that a multipronged policy approach that recognizes the driving forces of stigma and promotes social participation directly alongside psychosocial interventions on mental distress of persons with disabilities is necessary to achieve wellbeing for a group that has been historically and systematically excluded from development interventions.

A Cross-National Comparison of Suicide Attempts, Drug Use, and Depressed Mood Among Dominican Youth.

We compared suicide attempts, depressed mood, and drug use of 1,710 Dominican public high school students in New York City (NYC) and 9,573 in the Dominican Republic (DR) in 2009. Compared to DR Dominicans, NYC Dominicans were more likely to have reported lifetime marijuana use (27.6% vs. 1.5%), lifetime inhalant use (11.0% vs. 7.6%), lifetime other drug use (9.9% vs. 3.0%), depressed mood (31.3% vs. 27.2%), and suicide attempt (13.8% vs. 8.8%). The results of this study supported the hypothesis that substantial increases in illicit drug use, especially cocaine, heroin, ecstasy, and methamphetamines, among NYC Dominican youth account for their increased risk for suicide attempts compared to their DR Dominican counterparts. It also identified suicide attempts as a public health problem among NYC Dominicans, the largest NYC Latino immigrant population.

Evaluation of a brief computer-mediated intervention to reduce HIV risk among early adolescent females.

PURPOSE: To evaluate the efficacy of a brief computer-mediated intervention, relative to no intervention, in altering HIV/AIDS-related knowledge, protective attitudes, and self-efficacy for risk reduction among early adolescent females aged 11 through 14 years. METHOD: Recruited through the auspices of a large social services agency with multiple sites across New York City, a volunteer sample of 205 Black, White, and Hispanic young women participated in this research. The efficacy of the software intervention was examined in a randomized blocks design with site as the unit of randomization. Young women at experimental arm sites interacted with the software in a single 30-minute session. Youths at control arm sites participated in regular programs offered at these sites, but did not receive the intervention until all planned assessments were concluded. Before and after intervention, participants completed measures of HIV/AIDS-related knowledge, protective attitudes, and self-efficacy for HIV risk reduction. Analyses of covariance were used to test for significant between-arm effects. RESULTS: Between-arm effects were observed for HIV/AIDS-related knowledge and risk reduction self-efficacy. Experimental arm youths evidenced greater improvements from pretest to posttest than control-arm youths on these outcomes. CONCLUSION: Computer-mediated interventions may improve HIV/AIDS-related knowledge and risk reduction self-efficacy among early adolescent females. However, additional research is needed to find effective computer-mediated approaches for enhancing protective attitudes among this population.

Fish tolerance to organophosphate-induced oxidative stress is dependent on the glutathione metabolism and enhanced by N-acetylcysteine.

Dichlorvos (2,2-dichlorovinyl dimethyl phosphate, DDVP) is an organophosphorus (OP) insecticide and acaricide extensively used to treat external parasitic infections of farmed fish. In previous studies we have demonstrated the importance of the glutathione (GSH) metabolism in the resistance of the European eel (Anguilla anguilla L.) to thiocarbamate herbicides. The present work studied the effects of the antioxidant and glutathione pro-drug N-acetyl-L-cysteine (NAC) on the survival of a natural population of A. anguilla exposed to a lethal concentration of dichlorvos, focusing on the glutathione metabolism and the enzyme activities of acetylcholinesterase (AChE) and caspase-3 as biomarkers of neurotoxicity and induction of apoptosis, respectively. Fish pre-treated with NAC (1 mmol kg(-1), i.p.) and exposed to 1.5 mg l(-1) (the 96-h LC85) of dichlorvos for 96 h in a static-renewal system achieved an increase of the GSH content, GSH/GSSG ratio, hepatic glutathione reductase (GR), glutathione S-transferase (GST), glutamate:cysteine ligase (GCL), and gamma-glutamyl transferase (gammaGT) activities, which ameliorated the glutathione loss and oxidation, and enzyme inactivation, caused by the OP pesticide. Although NAC-treated fish presented a higher survival and were two-fold less likely to die within the study period of 96 h, Cox proportional hazard models showed that hepatic GSH/GSSG ratio was the best explanatory variable related to survival. Hence, tolerance to a lethal concentration of dichlorvos can be explained by the individual capacity to maintain and improve the hepatic glutathione redox status. Impairment of the GSH/GSSG ratio can lead to excessive oxidative stress and inhibition of caspase-3-like activity, inducing cell death by necrosis, and, ultimately, resulting in the death of the organism. We therefore propose a reconsideration of the individual effective dose or individual tolerance concept postulated by Gaddum 50 years ago for the log-normal dose-response relationship. In addition, as NAC increased the tolerance to dichlorvos, it could be a potential antidote for OP poisoning, complementary to current treatments.

Increased recovery of brain acetylcholinesterase activity in dichlorvos-intoxicated European eels Anguilla anguilla by bath treatment with N-acetylcysteine.

Organophosphate (OP) pesticides are widely used as antiparasitic chemicals in finfish aquaculture. However, current antidotes cannot be applied to treat intoxicated fish. We showed in previous studies the importance of glutathione (GSH) metabolism in pesticide resistance of the European eel Anguilla anguilla L. The present work studied the effects of the antioxidant and glutathione pro-drug N-acetyl-L-cysteine (NAC) on the recovery of European eels exposed for 96 h to a sublethal concentration (0.17 mg l(-1); 20% of its 96 h LC50) of the OP pesticide dichlorvos (2,2-dichlorovinyl dimethyl phosphate; DDVP). This insecticide and acaricide decreased muscular GSH content and increased oxidised glutathione (GSSG), lowering the GSH:GSSG ratio, which is indicative of a condition of oxidative stress. Acetylcholinesterase (AChE) and glutathione reductase (GR) activities in the brain, which were biomarkers of neurotoxicity and oxidative stress, respectively, were also highly inhibited. Recovery in a 0.5 mM (81.6 mg l(-1)) NAC concentration ameliorated muscular GSH depletion, GSH:GSSG ratio, and the inhibition of brain AChE and GR activities. Hence, this is the first evidence of improved recovery of organophosphate-poisoned fish by bath treatments.

N-Acetylcysteine boosts xenobiotic detoxification in shellfish.

Water pollution represents a threat of increasing importance to human health. Bivalve mollusks are filter-feeding organisms that can accumulate chemical and microbiological contaminants in their tissues from very low concentrations in the water or sediments. Consumption of contaminated shellfish is one of the main causes of seafood poisoning. Thus, marine bivalves are normally depurated in sterilized seawater for 48 h to allow the removal of bacteria. However, this depuration time might be insufficient to eliminate chemical contaminants from their tissues. We have developed a novel technology that accelerates up to fourfold the excretion rate of xenobiotics in bivalves by treatment with the antioxidant and glutathione (GSH) pro-drug N-acetylcysteine (NAC) during the depuration period. NAC improved dose-dependently the detoxification of the organophosphate (OP) pesticide fenitrothion in the mussel Mytilus galloprovincialis, diminishing its levels up to nearly a hundred fold compared to conventional depuration, by enhancing the glutathione S-transferase (GST) activity and inducing the GSH anabolism (GSH synthesis and reduction by glutathione reductase). Notably, this induction in GSH anabolism and GST activity was also observed in uncontaminated bivalves treated with NAC. As the GSH pathway is involved in the detoxification of many pollutants and biotoxins from harmful algal blooms, we validated this proof of principle in king scallops (Pecten maximus) that naturally accumulated the amnesic shellfish poisoning (ASP) toxin domoic acid. We illustrate here a method that enhances the elimination of organic contaminants in shellfish, opening new avenues of depuration of marine organisms.

Familism, family environment, and suicide attempts among Latina youth.

In this study, we examined the relationship between familism and family environment type as well as the relationship between family environment type and suicide attempts among Latina youth. Latina teen attempters (n = 109) and nonattempters (n = 107) were recruited from the New York City area. Latent class analysis revealed three family environment types: tight-knit, intermediate-knit, and loose-knit. Tight-knit families (high cohesion and low conflict) were significantly less likely to have teens who attempted suicide as compared with intermediate-knit families or loose-knit families. Moreover, familism increased the odds of being in a tight-knit family versus a loose-knit family and the odds of being in a tight-knit family versus a intermediate-knit. The results suggest that familism may protect against suicide behavior among Latinas via its influence on family environment.

Accelerating Research Productivity in Social Work Programs: Perspectives on NIH's Postdoctoral T32 Research Training Mechanism.

This article describes the experiences of four social work researchers who pursued an alternative career path immediately following their doctorate in social work by accepting a postdoctoral training fellowship funded by the National Institutes of Health (NIH). As schools of social work look for creative ways to build research capacity, this article describes the authors' perspectives regarding the considerations to accept postdocs, key elements in their training programs, lessons learned, and outcomes from training. To provide an overview of the funding mechanism and distribution of funds to institutes and centers relevant to social work, data were obtained from databases that list NIH training grants awarded each year. Study results showed a limited amount of variation in fellows' training plans. The majority of training time was spent building skill in manuscript preparation, grant development, and socialization to the NIH culture. Above all other themes, the desire for advanced research training was a critically important factor in accepting a postdoctoral training position. Finally, the outcomes of training may have a profound effect on professional development, yet the long-term trajectory of postdoctoral fellows in academic positions as compared with people without postdoctoral training in social work programs requires further study.

Immigration generation status and its association with suicide attempts, substance use, and depressive symptoms among latino adolescents in the USA.

This study investigated the relation between suicide attempts and immigrant generation status using the Latino subset of the National Longitudinal Study of Adolescent Health, a school-based, nationally representative sample. This study also examined whether generation status predicted risk factors associated with elevated suicide behaviors, namely illicit substance use, problematic alcohol use, and depressive symptoms. Finally, hypothesizing that elevated depressive symptoms and substance use mediate the relation between immigrant generation status and suicide attempts among Latino adolescents, a path model was tested. Our findings revealed immigrant generation status was a determinant for suicide attempts, problematic alcohol use, repeated marijuana use, and repeated other drug use for Latino adolescents. US-born Latinos with immigrant parents (i.e., second-generation youth) were 2.87 (95% CI, 1.34, 6.14) times more likely to attempt suicide, 2.27 (95% CI, 1.53, 3.35) times more likely to engage in problematic alcohol use, 2.56 (95% CI, 1.62, 4.05) times more likely to engage in repeated marijuana use, and 2.28 (95% CI, 1.25, 4.17) times more likely to engage in repeated other drug use than were foreign-born youth (i.e., first-generation youth). Later-generations of US-born Latino youth with US-born parents were 3.57 (95% CI, 1.53-8.34) times more likely to attempt suicide, 3.34 (95% CI, 2.18-5.11) times more likely to engage in problematic alcohol use, 3.90 (95% CI, 2.46, 6.20) times more likely to engage in repeated marijuana use, and 2.80 (95% CI, 1.46, 5.34) times more likely to engage in repeated other drug use than were first-generation youth. Results from the path analysis indicated that repeated other drug use may mediate the effect of generation status on suicide attempts.