ProtocadherinX/Y, a candidate gene-pair for schizophrenia and schizoaffective disorder: a DHPLC investigation of genomic sequence.

Protocadherin X and Protocadherin Y (PCDHX and PCDHY) are cell-surface adhesion molecules expressed predominantly in the brain. The PCDHX/Y gene-pair was generated by an X-Y translocation approximately 3 million years ago (MYA) that gave rise to the Homo sapiens-specific region of Xq21.3 and Yp11.2 homology. Genes within this region are expected to code for sexually dimorphic human characteristics, including, for example, cerebral asymmetry a dimension of variation that has been suggested is relevant to psychosis. We examined differences in patients with schizophrenic or schizoaffective psychosis in the genomic sequence of PCDHX and PCDHY in coding and adjacent intronic sequences using denaturing high performance liquid chromatography (DHPLC). Three coding variants were detected in PCDHX and two in PCDHY. However, neither the coding variants nor the intronic polymorphisms could be related to psychosis within families. Low sequence variation suggests selective pressure against sequence change in modern humans in contrast to the structural chromosomal and sequence changes including fixed X-Y differences that occurred in this region earlier in hominid evolution. Our findings exclude sequence variation in PCDHX/Y as relevant to the aetiology of psychosis. However, we note the unusual status of this region with respect to X-inactivation. Further investigation of the epigenetic control of PCDHX/Y in relation to psychosis is warranted.     

High prevalence of vitamin D insufficiency in healthy Irish adults

Background  Specific sub-groups of the population, such as older people, are at increased risk of poor vitamin D status. There is growing evidence, however, that vitamin D insufficiency may be a more widespread problem. Aim  To determine the prevalence of vitamin D insufficiency in a group of healthy Irish adults. Methods  Serum 25-hydroxyvitamin D was measured by radioimmunoassay in 70 healthy Irish adults working in South Dublin. Results  Overall, half of the group (51%) had vitamin D insufficiency; this was more pronounced in wintertime, with prevalence rising to 58%. Winter was a significant negative predictor of serum 25-OH D levels. Sixteen percent of the participants reported taking a vitamin D-containing supplement (multivitamin), but this did not significantly influence the serum 25-OH D levels. Conclusion  Vitamin D insufficiency is not confined to “at-risk groups” and is likely to be prevalent in the general public in Ireland, especially in wintertime.     

Cation-osmotic haemolysis in stroke patients

Erythrocyte microrheology changes were measured by cation-osmotic haemolysis (COH) in healthy donors, patients with ischameic stroke, and patients who died within four days after a stroke. COH in patients with stroke was significantly decreased in comparison with that from healthy donors. In patients who died, COH was significantly decreased compared to patients who survived. The relationship between cationosmotic haemolysis and erythrocyte deformability is discussed.     

Bullying Victimization Among LGBTQ Youth: Critical Issues and Future Directions

Purpose of Review

This paper examines recent research on bullying victimization among lesbian, gay, bisexual, transgender, and queer (LGBTQ) youth to identify critical issues and advocate for future research priorities.

Recent Findings

Recent studies have begun to document the importance of bullying in general, and bias-based bullying (rooted in stigma) in particular, on the health and well-being of this vulnerable subgroup of adolescents, as well as drivers of disparities. Current research demonstrates the importance of multiple, overlapping identities, key difference among LGBTQ youth, and the role of protective factors for youth who are the targets of bullying.

Summary

Researchers, clinicians, and those working with and on behalf of LGBTQ youth must measure and acknowledge the multiple reasons for which LGBTQ youth are the targets of bullying. Intervention and prevention efforts should focus on improving the supportiveness of the climates within which LGBTQ youth live.

     

Unresolved–Disorganized Attachment is Associated With Smaller Hippocampus and Increased Functional Connectivity Beyond Psychopathology

Loss and abuse in children can lead to unresolved–disorganized (UD) attachment. How this condition relates to brain structure and functional connectivity (FC) is unknown. We therefore aimed to investigate gray matter volume (GMV) and resting state functional connectivity (RSFC) correlates of UD attachment in adolescents. Based on previous neuroimaging studies of trauma effects, we hypothesized that the structure of the amygdala and hippocampus and the FC of the latter would be linked to UD attachment. Anatomical and RSFC data were collected from a mixed group of adolescents (N = 74) with symptoms of posttraumatic stress disorder (PTSD) related to childhood sexual abuse (CSA), anxiety/depressive symptoms, and without psychiatric disorder as part of the Emotional Pathways’ Imaging Study in Clinical Adolescents (EPISCA). Bilateral volumes of the amygdala and hippocampus were measured using the FMRIB Software Library, and RSFC of the hippocampus was assessed using seed‐based correlation. UD attachment was measured using the Adult Attachment Interview. Hierarchical regression and correlation were used to assess the associations between UD status (continuous and categorical), brain structure, and FC, adjusting for a general psychopathology factor, puberty stage, gender, age, and IQ. UD attachment was associated with a smaller left hippocampal volume, R² = .23, and a higher level of FC between the hippocampus and the middle temporal gyrus and lateral occipital cortex. The associations among UD attachment, specific brain structure, and FC across psychopathological classifications shows promise for dimensional complements to the dominant classificatory approach in clinical research and practice.     

Cognitive enhancers for facilitating drug cue extinction: insights from animal models

Given the success of cue exposure (extinction) therapy combined with a cognitive enhancer for reducing anxiety, it is anticipated that this approach will prove more efficacious than exposure therapy alone in preventing relapse in individuals with substance use disorders. Several factors may undermine the efficacy of exposure therapy for substance use disorders, but we suspect that neurocognitive impairments associated with chronic drug use are an important contributing factor. Numerous insights on these issues are gained from research using animal models of addiction. In this review, the relationship between brain sites whose learning, memory and executive functions are impaired by chronic drug use and brain sites that are important for effective drug cue extinction learning is explored first. This is followed by an overview of animal research showing improved treatment outcome for drug addiction (e.g. alcohol, amphetamine, cocaine, heroin) when explicit extinction training is conducted in combination with acute dosing of a cognitive-enhancing drug. The mechanism by which cognitive enhancers are thought to exert their benefits is by facilitating consolidation of drug cue extinction memory after activation of glutamatergic receptors. Based on the encouraging work in animals, factors that may be important for the treatment of drug addiction are considered.