The results suggest that MBCT could work through some of the MBCT model's theoretically predicted mechanisms. However, there is a need for more rigorous designs that can assess greater levels of causal specificity.
Summary1. Thermal adaptation was investigated in the fruitfly Drosophila buzzatii Patterson and Wheeler. Two natural populations originating from a high-and a low-temperature environment, respectively, were compared with respect to Hsp70 (heat shock protein) expression, knock-down resistance and heat shock resistance. 2. Three main hypotheses were tested: (i) The expression level of Hsp70 in flies from the high-temperature habitat should be down-regulated relative to flies from the colder habitat. (ii) Flies having higher Hsp70 expression levels should be weakened most by a hardening treatment and go faster into coma, as Hsp70 level reflects stress intensity, and therefore display reduced heat knock-down resistance. (iii) Heat shock resistance should be increased in the population with highest Hsp70 expression because the level of Hsp70 is positively associated with this trait. 3. The results generally matched the hypotheses. Hsp70 expression was reduced in the high-temperature population. Knock-down resistance was higher in the hightemperature population and survival after heat shock was lower in the high-temperature population. 4. This study showed genetic differences in thermal tolerance between populations, indicating that high temperature in nature may be an important selective factor. Moreover, knock-down resistance in this study seems to be a more relevant trait than standard heat shock resistance for identifying thermal adaptation in natural populations.
1. Inducible heat‐shock proteins are synthesized when temperatures are increased to levels substantially above normal. The functional role of these proteins is well known at the cellular level. Today increasing interest has been directed towards the importance of heat‐shock proteins for resistance of whole organisms to high‐temperature stress and other environmental stressors. 2. Here the functional relationship between the heat‐shock protein, Hsp70, and thermal resistance in adult Drosophila melanogaster was examined by comparing thermal resistance, i.e. survival at 39 °C for 85 min, and levels of Hsp70 at various times elapsed (2, 4, 8, 16, 32 and 64 h) after thermotolerance was induced by short‐term acclimation/heat hardening at 37 °C for 55 min. 3. Levels of Hsp70 in both males and females were highest 2 h after heat hardening and declined with longer times elapsed. The rate of decrease initially was very fast but diminished with increasing time. After 32 h the level of Hsp70 approached the level in flies that were not hardened. Levels of Hsp70 in males exceeded that of females during the entire period. 4. Survival of both sexes increased with increasing time after heat hardening and reached an optimum between 8 and 32 h. Thereafter resistance decreased with longer times elapsed. Survival of females generally exceeded that of males except after 16 and 64 h. 5. Regression analysis applied to the data on Hsp70 levels revealed that the model describing these data could not explain the data for survival. Also, higher levels of Hsp70 in males compared with females were not associated with greater survival in males. However, statistical analysis on paired measurements of Hsp70 and survival revealed a positive association between Hsp70 level and survival at each time elapsed after induction of thermotolerance.
BackgroundInsomnia is two to three times more prevalent in cancer survivors than in the general population, where it is estimated to be 10% to 20%. Cognitive-behavioral therapy for insomnia (CBT-I) is the recommended treatment for chronic insomnia, but meeting survivor needs remains a challenge. Internet-delivered CBT-I (iCBT-I) has been shown efficacious in otherwise healthy adults. We tested the efficacy of iCBT-I in breast cancer survivors with clinically significant sleep disturbance.MethodsWomen from a national sample of Danish breast cancer survivors who experienced clinically significant sleep disturbance were randomly allocated to iCBT-I or waitlist control (55:45). The fully automated iCBT-I program consisted of six cores. Online measures of insomnia severity, sleep quality, and fatigue were collected at baseline, postintervention (nine weeks), and follow-up (15 weeks). Online sleep diaries were completed over two-week periods pre- and postintervention. Intention-to-treat analyses (time × group interactions) were conducted with mixed linear models and corrected for multiple outcomes. All statistical tests were two-sided.ResultsA total of 255 women were randomly allocated to iCBT-I (n = 133) or waitlist control (n = 122). Statistically significant (P ≤ .02) time × group interactions were found for all sleep-related outcomes from pre- to postintervention. Effect sizes (Cohen’s d) ranged from 0.33 (95% confidence interval [CI] = 0.06 to 0.61) for wake after sleep onset to 1.17 (95% CI = 0.87 to 1.47) for insomnia severity. Improvements were maintained for outcomes measured at follow-up (d = 0.66–1.10).ConclusionsiCBT-I appears to be effective in breast cancer survivors, with additional benefit in terms of reduced fatigue. This low-cost treatment could be incorporated in cancer rehabilitation programs.
Knockdown resistance to high temperature is an ecologically important trait in small insects. A composite interval mapping was performed on the two major autosomes of Drosophila melanogaster to search for quantitative trait loci (QTL) affecting knockdown resistance to high temperature (KRHT). Two dramatically divergent lines from geographically different thermal environments were artificially selected on KRHT. These lines were crossed to produce two backcross (BC) populations. Each BC was analysed for 200 males with 18 marker loci on chromosomes 2 and 3. Three X-linked markers were used to test for X-linked QTL in an exploratory way. The largest estimate of autosome additive effects was found in the pericentromeric region of chromosome 2, accounting for 19.26% (BC to the low line) and 29.15% (BC to the high line) of the phenotypic variance in BC populations, but it could represent multiple closely linked QTL. Complete dominance was apparent for three QTL on chromosome 3, where heat-shock genes are concentrated. Exploratory analysis of chromosome X indicated a substantial contribution of this chromosome to KRHT. The results show that a large-effect QTL with dominant gene action maps on the right arm of chromosome 3. Further, the results confirm that QTL for heat resistance are not limited to chromosome 3.
Both inbreeding and environmental stress can have adverse effects on fitness that affect the conservation of endangered species. Two important issues are whether stress and inbreeding effects are independent as opposed to synergistic, and whether inbreeding effects are general across stresses as opposed to stress‐specific. We found that inbreeding reduced resistance to acetone and desiccation in adult Drosophila melanogaster, whereas resistance to knockdown heat stress was not affected. Inbred flies, however, experienced a greater proportional decrease in productivity than outbreds following heat stress. Correlations using line means indicated that all resistance traits were uncorrelated in the inbred as well as in the outbred flies. Recessive, deleterious alleles therefore did not appear to have any general deleterious effects on stress resistance. Inbreeding within a specific environment and selection for resistant genotypes may therefore purge a population of deleterious genes specific to only one environmental stress.
dlk1/FA1 (delta-like 1/fetal antigen-1) is a member of the epidermal growth factor-like homeotic protein family whose expression is known to modulate the differentiation signals of mesenchymal and hematopoietic stem cells in bone marrow. We have demonstrated previously that Dlk1 can maintain the human bone marrow mesenchymal stem cells (hMSC) in an undifferentiated state. To identify the molecular mechanisms underlying these effects, we compared the basal gene expression pattern in Dlk1-overexpressing hMSC cells (hMSC-dlk1) versus control hMSC (negative for Dlk1 expression) by using Affymetrix HG-U133A microarrays. In response to Dlk1 expression, 128 genes were significantly up-regulated (with >2-fold; p < 0.001), and 24% of these genes were annotated as immune response-related factors, including pro-inflammatory cytokines, in addition to factors involved in the complement system, apoptosis, and cell adhesion. Also, addition of purified FA1 to hMSC up-regulated the same factors in a dose-dependent manner. As biological consequences of up-regulating these immune response-related factors, we showed that the inhibitory effects of dlk1 on osteoblast and adipocyte differentiation of hMSC are associated with Dlk1-induced cytokine expression. Furthermore, Dlk1 promoted B cell proliferation, synergized the immune response effects of the bacterial endotoxin lipopolysaccharide on hMSC, and led to marked transactivation of the NF-B. Our data suggest a new role for Dlk1 in regulating the multiple biological functions of hMSC by influencing the composition of their microenvironment "niche." Our findings also demonstrate a role for Dlk1 in mediating the immune response.
Research has proven that both mindfulness training and exposure to nature have positive health effects. The purpose of this study was to systematically review quantitative studies of mindfulness interventions conducted in nature (nature-based mindfulness), and to analyze the effects through meta-analyses. Electronic searches revealed a total of 25 studies to be included, examining 2990 participants. Three analyses were conducted: Nature-based mindfulness interventions evaluated as open trials (k = 13), nature-based mindfulness compared with groups in non-active control conditions (k = 5), and nature-based mindfulness compared with similar interventions but without contact with nature (k = 7). The overall combined psychological, physiological, and interpersonal effects from pre- to post-intervention were statistically significant and of medium size (g = 0.54, p < 0.001). Moderation analyses showed that natural environments characterized as forests/wild nature obtained larger numerical effects than environments characterized as gardens/parks, as did informal mindfulness compared with formal mindfulness. The small number of studies included, as well as the heterogeneity and generally low quality of the studies, must be taken into consideration when the results are interpreted. PROSPERO registration number: CRD42017065639.
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