Delay discounting, genetic sensitivity, and leukocyte telomere length.

In a graying world, there is an increasing interest in correlates of aging, especially those found in early life. Leukocyte telomere length (LTL) is an emerging marker of aging at the cellular level, but little is known regarding its link with poor decision making that often entails being overly impatient. Here we investigate the relationship between LTL and the degree of impatience, which is measured in the laboratory using an incentivized delay discounting task. In a sample of 1,158 Han Chinese undergraduates, we observe that steeper delay discounting, indexing higher degree of impatience, is negatively associated with LTL. The relationship is robust after controlling for health-related variables, as well as risk attitude-another important determinant of decision making. LTL in females is more sensitive to impatience than in males. We then asked if genes possibly modulate the effect of impatient behavior on LTL. The oxytocin receptor gene (OXTR) polymorphism rs53576, which has figured prominently in investigations of social cognition and psychological resources, and the estrogen receptor ß gene (ESR2) polymorphism rs2978381, one of two gonadal sex hormone genes, significantly mitigate the negative effect of impatience on cellular aging in females. The current results contribute to understanding the relationship between preferences in decision making, particularly impatience, and cellular aging, for the first time to our knowledge. Notably, oxytocin and estrogen receptor polymorphisms temper accelerated cellular aging in young females who tend to make impatient choices.

Long-Term Tissue Preservation at Ambient Temperature for Post-Mass Fatality Incident DNA-Based Victim Identification.

In a mass fatality incident (MFI), effective preservation of tissue samples is the cornerstone for downstream DNA-based identification of victims. This is commonly achieved through freezing of tissue samples excised from bodies/fragmented remains which may be buried or stored in refrigerated containers. This may, however, not be possible depending on the nature of the MFI; in particular, during armed conflict/war where extended periods of electrical outages would be expected. The present study compared the effectiveness of long-term tissue preservation at ambient temperatures using two commercial products (non-iodized kitchen salt and a 40% alcoholic beverage) against a chemical preservative (Allprotect™ Tissue Reagent (Qiagen, Germantown, MD, USA)) and freezing at -20 °C. Bovine muscle tissue, used as a proxy for human tissue, was treated with the four preservation methods and sampled at six different time-points over a 24-month period. All four methods were able to preserve the bovine tissue, generally yielding STR-PCR (Short Tandem Repeat-Polymerase Chain Reaction) amplicons > 200 bp in size even at the end of 24 months. Gel electrophoresis, however, indicated that salt was more effective in preserving DNA integrity with high-molecular-weight DNA clearly visible as compared to the low-molecular-weight DNA smears observed in the other methods. This study also proposes a simple process for the rapid and low-cost preservation of tissue samples for long-term storage at ambient temperatures in support of post-incident victim identification efforts.

Detection of hemi/homozygotes through heteroduplex formation in high-resolution melting analysis.

Heteroduplex formation, required for the complete detection of hemi/homozygotes using high-resolution melting analysis, can be induced either by pre-PCR mixing of genomic DNAs or by post-PCR mixing of PCR products from unknown and reference samples. This study investigates the effects of both methods using two single nucleotide polymorphisms in X-linked DMD gene. The results show that both methods resulted in the same effect when mixing samples with the same gene copy number. Mixing samples with different gene copy numbers has not been previously explored and we show that post-PCR mixing is insensitive to gene copy number differences as compared to pre-PCR mixing.

Correction to: Association among dispositional mindfulness, self-compassion, and leukocyte telomere length in Chinese adults.

An amendment to this paper has been published and can be accessed via the original article.

Effects of Mindfulness-Based Stress Reduction on Psychological Symptoms and Telomere Length: A Randomized Active-Controlled Trial.

Much research has demonstrated the beneficial effects of mindfulness-based stress reduction (MBSR) on psychological and physical health, but it is not known whether MBSR may impact cellular aging in healthy populations. Further, little research has evaluated MBSR against an active control condition, which precludes strong conclusions regarding the unique effects of mindfulness on psychological functioning. The present study examined the effects of MBSR versus music therapy-based stress reduction (MTSR) on trait mindfulness, self-compassion, and several psychological health outcomes, as well as leukocyte telomere length (LTL). One hundred and fifty eight Singaporean Chinese adults were recruited and randomly assigned to an eight-week MBSR or MTSR course. Participants provided blood samples and completed a battery of self-report measures pre- and post-intervention. Analyses showed that participants in the MBSR condition demonstrated significantly greater improvements in depressive symptoms, trait mindfulness, and self-compassion compared to the control condition. Treatment condition did not predict changes in LTL, anxiety, stress, or happiness, though there was a trend for duration of home mindfulness practice to predict increases in LTL. Overall, the study demonstrated MBSR's unique effects in reducing depressive symptoms. Improvements in trait mindfulness and self-compassion correspond with theorized mechanisms of change underlying mindfulness training. The lack of intervention effect with regards to LTL suggests that a more intensive intervention may be required for mindfulness to exert noticeable impact on aging at the cellular level, or that the effect may only emerge over a longer term.

Association among dispositional mindfulness, self-compassion, and leukocyte telomere length in Chinese adults.

BACKGROUND: Whereas meditation training has been purported to support slower cellular aging, little work has explored the association among different facets of dispositional mindfulness, self-compassion, and cellular aging. The present study aimed to examine the relationship between leukocyte telomere length (LTL), an index of cellular aging, dispositional mindfulness, and self-compassion in a sample of Singaporean Chinese adults. METHODS: One hundred and fifty-eight Chinese adults (mean age = 27.24 years; 63.3% female) were recruited from the community and completed self-report measures assessing dispositional mindfulness, self-compassion, and psychological symptoms, as well as provided blood samples for analyses of LTL. Multiple regression analyses were conducted to examine the role of trait mindfulness and self-compassion in predicting LTL, taking into consideration potential covariates such as chronological age and psychological symptoms. RESULTS: Results showed that nonreactivity, one of the five facets of dispositional mindfulness, was significantly associated with LTL, after controlling for chronological age. There was also a trend for dispositional mindfulness, self-compassion, and their selected facets (i.e., nonjudging, common humanity, and de-identification) to each be associated with longer LTL. CONCLUSIONS: Overall, the findings provide preliminary support for the association among aspects of dispositional mindfulness, self-compassion, and aging. In particular, individuals high on nonreactivity experience slower aging at the cellular level, likely through engaging in more adaptive coping mechanisms.

Successful aging, cognitive function, socioeconomic status, and leukocyte telomere length.

In a rapidly greying world, the notion that some individuals maintain successful aging trajectories, viz. high physical, cognitive, emotional, and social functioning in older age, is increasingly germane. Biomarkers of such successful aging are increasingly sought. Leukocyte telomere length (LTL), an emerging yardstick of cellular aging that is influenced by but distinct from chronological age, may also be associated to successful aging. Furthermore, given that socio-economic status (SES) influences successful aging trajectories, socioeconomic status may also moderate the association between chronological age and LTL. The goals of this study are to examine 1) whether successful aging is associated with LTL; 2) whether successful aging accounts for age-related LTL and 3) whether SES moderates the effect of age on LTL. Singaporean Chinese (n = 353) aged 65-80 completed a multidimensional assessment of successful aging and provided blood samples for LTL analysis. Results show that LTL negatively correlates with chronological age and positively correlates with successful aging. Successful aging mediates the association between chronological age and LTL. Moderated mediation analyses show that lower SES is associated with stronger negative associations of chronological age with successful aging and LTL. Moreover, the cognitive functioning dimension of successful aging is uniquely associated with LTL and its association with chronological age is moderated by SES. This study provides evidence that among older Singaporean Chinese with lower SES, declines in successful aging and in cognitive functioning are linked to age-related LTL shortening and hence to accelerated aging at the cellular level.

Dimeric gold nanoparticle assembly for detection and discrimination of single nucleotide mutation in Duchenne muscular dystrophy.

Nanoparticles are increasingly being used for applications in clinical diagnostics due to their unique physical and chemical properties. Gold nanoparticles, in particular, have unique optical properties allowing simplicity of detection methods. In this study, an assay based on dimeric assembly of gold nanoparticles was developed for discriminating single nucleotide mismatches. Only gel electrophoresis is needed for assay readout. No other sophisticated or expensive equipment is required. In addition, no false-positive was observed in the readout. We used this assay for genotyping mutations in the Duchenne muscular dystrophy (DMD) gene, the largest known in the human genome. Our results show that conjugating the gold nanoparticles with short DNA probes of 18 bases and 70 bases complimentary to target sequences allows specific discrimination between wild-type and mutant sequences for c.4150G > T (NM.004006.1) mutation in exon 30 of the DMD gene using a simple colorimetric detection. This method allows identification of both the patients as well as the carriers of the mutation who are at risk of transmitting the disease.