Type D personality and cardiovascular reactivity to acute stress: The mediating effects of social support and negative social relationships

Type D personality has been consistently associated with adverse cardiovascular health with atypical cardiovascular reactions to psychological stress one potential underlying mechanism. As Type D individuals have been noted to report lower social support and greater perceptions of negativity in social interactions, this study examined if the association between Type D personality and cardiovascular reactivity was mediated by these social relationships. A sample of 195 undergraduate students (138 female) participated in this observational study, where they completed measures assessing Type D personality (DS14), social support, and perceptions of negative social relationships (National Institute of Health social relationship scales), before undergoing a traditional cardiovascular reactivity protocol. Systolic and diastolic blood pressure (SBP; DBP), heart rate (HR), cardiac output (CO), and total peripheral resistance (TPR) were monitored throughout. ANCOVAs and regressions indicated that Type D personality was associated with lower cardiovascular reactivity to a mental arithmetic stressor. Furthermore, mediation analyses (process macro) indicated that the relationship between Type D personality and cardiovascular reactivity was mediated via increased perceptions of negative social relationships, as well as lower levels of social support. Apart from a significant association between Type D personality and increased HR reactivity, all results failed to withstand adjustment for the individual effects of negative affect (NA) and social inhibition (SI) in controlled analyses. Overall, these findings suggest that the predictive utility of Type D personality on cardiovascular reactivity above and beyond the individual effects of NA and SI is limited, and may vary depending on the cardiovascular parameter of focus.     

Mentors' experiences of mentoring justice-involved adolescents: A narrative of developing cultural consciousness through connection

Mentoring provides a relational intervention that can promote positive youth development among adolescents who are involved in the juvenile justice system. The perspectives of mentors engaging these youth, particularly insights considered through a cultural humility lens, have been largely absent from the literature to date. This study examined predominately White, middle- to upper-class adult mentors' experiences mentoring racially diverse, working-class youth. Semi-structured qualitative interviews were completed with 23 mentors participating in a community-based mentoring program. Themes were derived from inductive content analysis. Emergent themes illustrative of the mentoring process included (a) establishing a connection despite differences, (b) identifying mentees' personal and environmental challenges, and (c) raising consciousness around structural issues. Despite coming from different backgrounds and experiences, mentors who worked with justice-involved adolescents were motivated to connect with their mentees. Mentors developed a greater awareness of structural challenges influencing adolescents by learning about the multifaceted experiences and needs of their mentees.     

Pharmacokinetic and pharmacodynamic study of a clinically effective anti-CD2 monoclonal antibody

The humanized IgG1κ monoclonal antibody siplizumab and its rat parent monoclonal IgG2b antibody BTI-322 are directed against the CD2 antigen. Siplizumab is species-specific, reacting with human and chimpanzee cells but not with cells from any other species, including other non-human primates. Because siplizumab treatment has recently shown great potential in clinical transplantation, we now present the results of our previous pharmacokinetic, pharmacodynamic and safety studies of both antibodies. Fourteen chimpanzees received 1-3 doses of 0.143 to 5.0 mg/kg iv The effects were followed with flow cytometry on peripheral lymphocytes and staining of lymph nodes. Side effects were recorded. Serum antibody concentrations were followed. Across the doses, a rapid, transient depletion of CD2, CD3, CD4 and CD8 lymphocytes and NK cells was observed for both antibodies. Immune reconstitution was more rapid for BTI-322 compared to siplizumab. Paracortical lymph node T cell depletion was moderate, estimated at 45% with doses of >0.6 mg/kg. Restoration of lymph node architecture was seen after two weeks to two months for all animals. All four subjects receiving BTI-322 experienced AEs on the first dosing day, while the eight subjects dosed with siplizumab experienced few mild, transient AEs. Infusion with siplizumab and BTI-322 resulted in rapid depletion of CD2⁺ cells in circulation and tissue. Siplizumab had a longer t_1/2 and fewer AEs compared to BTI-322.     

The role of psychological and social factors in the relationship between attachment and suicide: A systematic review

Insecure attachment is widely accepted to be a risk factor for suicidal thoughts and behaviour. To increase our understanding of this distal association, the current systematic review aimed to evaluate empirical evidence that has investigated the role of psychosocial mechanisms within this relationship. Sixteen original research articles were identified, with the majority carrying out mediational analyses to test their hypotheses. Substantial heterogeneity was found across studies with regards to their theoretical approach to assessing attachment, suicide‐related outcomes, sample population, statistical analyses, and the psychological factors under investigation. Nevertheless, this emergent evidence base indicates that a range of predisposing, precipitating, and crisis‐state factors may mediate the association between attachment security and suicidality. Studies that investigated moderating factors did not report significant findings, and the mediating role for psychiatric diagnoses remains unclear. Furthermore, this emerging research base is limited by an over‐reliance on cross‐sectional designs and self‐reported data. Longitudinal and experimental designs are required to verify causal pathways and to investigate whether trait vulnerabilities interact with acute stressors to increase suicide risk. Finally, disorganized attachment has been overlooked so far and should be given greater consideration going forward.     

Xdrop: Targeted sequencing of long DNA molecules from low input samples using droplet sorting

Long‐read sequencing can resolve regions of the genome that are inaccessible to short reads, and therefore are ideal for genome‐gap closure, solving structural rearrangements and sequencing through repetitive elements. Here we introduce the Xdrop technology: a novel microfluidic‐based system that allows for targeted enrichment of long DNA molecules starting from only a few nanograms of DNA. Xdrop is based on the isolation of long DNA fragments in millions of droplets, where the droplets containing a target sequence of interest are fluorescently labeled and sorted using flow cytometry. The final product from the Xdrop procedure is an enriched population of long DNA molecules that can be investigated by sequencing. To demonstrate the capability of Xdrop, we performed enrichment of the human papilloma virus 18 integrated into the genome of human HeLa cells. Analysis of the sequencing reads resolved three HPV18‐chr8 integrations at base‐pair resolution, and the captured fragments extended up to 30 kb into the human genome at the integration sites. Further, we enriched the complete TP53 locus in a leukemia cell line and could successfully phase coexisting mutations using PacBio sequencing. In summary, our results show that Xdrop is an efficient enrichment technology for studying complex genomic regions.     

The Ontogeny of Masticatory Muscle Architecture in Microcebus murinus

The masticatory apparatus has been the focus of many studies in comparative anatomy—especially analyses of skulls and teeth, but also of the mandibular adductor muscles which are responsible for the production of bite force and the movements of the mandible during food processing and transport. The fiber architecture of these muscles has been correlated to specific diets (e.g., prey size in felids) and modes of foraging (e.g., tree gouging in marmosets). Despite the well-elucidated functional implications of this architecture, little is known about its ontogeny. To characterize age-related myological changes, we studied the masticatory muscles in a large (n = 33) intraspecific sample of a small, Malagasy primate, Microcebus murinus including neonatal through geriatric individuals. We removed each of the mandibular adductors and recorded its mass as well as other linear measurements. We then chemically dissected each muscle to study its architecture—fascicle length and physiological cross-sectional area (PCSA) which relate to stretch (gape) and force capabilities, respectively. We observed PCSA and muscle mass to increase rapidly and plateau in adulthood through senescence. Fascicle lengths remained relatively constant once maximal length was reached, which occurred early in life, suggesting that subsequent changes in PCSA are driven by changes in muscle mass. Quadratic curvilinear models of each of the architectural variables of all adductors combined as well as individual muscles regressed against age were all significant. Anat Rec, 303:1364–1373, 2020. © 2019 American Association for Anatomy     

DiceCT Analysis of the Extreme Gouging Adaptations Within the Masticatory Apparatus of the Aye-Aye (Daubentonia madagascariensis)

Relative to all other primates, the aye-aye (Daubentonia madagascariensis) exists at the extremes of both morphology and behavior. Its specialized anatomy—which includes hypselodont incisors and highly derived manual digits—reflects a dietary niche, unique among primates, which combines tap-foraging with gouging to locate and extract wood-boring larvae. Here, we explore the impact of this extreme dietary ecology upon the masticatory musculature of this taxon with reference to a second, similarly sized but highly generalist lemuriform—the mongoose lemur (Eulemur mongoz). Using non-destructive, high-resolution diffusible iodine-based contrast-enhanced computed tomography techniques, we reconstruct the three-dimensional volumes of eight masticatory muscles, and, for the first time in strepsirrhines, isolate and visualize their constituent muscle fascicles in situ and in three dimensions. Using these data, we report muscle volumes, forces, and fascicle lengths from each muscle portion, as well as their orientation relative to two standardized anatomical planes. Our findings demonstrate the overbuilt nature of the aye-aye's masticatory apparatus, in which each muscle possesses an absolutely and relatively larger muscle volume and PCSA than its counterpart in the mongoose lemur. Likewise, for several adductor muscles, aye-ayes also possess relatively greater fascicle lengths. Finally, we note several unusual features within the lateral pterygoid of the aye-aye—the muscle most responsible for jaw protrusion—that relate to force maximization and reorientation. As this jaw motion is critical to gouging, we interpret these differences to reflect highly specific specializations that facilitate the aye-aye's extreme subsistence strategy. Anat Rec, 2019. © 2019 American Association for Anatomy Anat Rec, 303:282–294, 2020. © 2019 American Association for Anatomy