Cognitive correlates of worry in adolescents

Although research on worry has increased over the past 15 years, few studies have examined worry in adolescents (Vasey, 1993). Recently, Dugas and his colleagues (1998) have developed a model of excessive worry that has been highly effective for predicting the tendency to worry in adults. This model proposes that four process variables are associated with excessive worry: intolerance of uncertainty, positive beliefs about worry, negative problem orientation, and cognitive avoidance. The goal of the present study is to explore the relationship between worry and these cognitive processes in an adolescent sample. Five hundred and twenty-eight participants aged 14 to 18 years completed questionnaires assessing worry, somatic anxiety symptoms, intolerance of uncertainty, positive beliefs about worry, negative problem orientation, and cognitive avoidance. The first hypothesis, which predicted that each of the four process variables would make a unique contribution to the prediction of worry, was partially supported. Specifically, intolerance of uncertainty, positive beliefs about worry, and negative problem orientation made a unique contribution to the prediction of adolescent worry. The second hypothesis, which postulated that the four process variables would contribute to the discriminant function and that the discriminant function would be effective in classifying moderate and high worriers into their respective groups, was also partially supported. Results revealed that 72.8% of the original grouped cases were correctly classified. Finally, the third hypothesis, which proposed that intolerance of uncertainty would make the most important contribution to the prediction of worry and would be the most important variable in discriminating between moderate and high worry groups, was supported. Results suggest that intolerance of uncertainty may be a key construct implicated in the development and maintenance of worry in adolescence

The relationship between adolescent worry, intolerance of uncertainty, and fear of anxiety

The primary goal of this research was to investigate the relationship between worry, intolerance of uncertainty, and fear of anxiety in a community sample of adolescents. Study 1 examined the association between adolescent worry, intolerance of uncertainty, and fear of anxiety ( N = 258). The results showed that intolerance of uncertainty and fear of anxiety were strongly, uniquely, and specifically related to adolescent worry above and beyond shared variance with gender, depression, and trait anxiety. The interaction between intolerance of uncertainty and fear of anxiety did not significantly predict worry above their separate and unique effects. Study 2 sought to delineate the normative adolescent trajectories of worry, intolerance of uncertainty, and fear of anxiety over time, and explored the longitudinal nature of the associations between worry and intolerance of uncertainty, and between worry and fear of anxiety ( N = 338). Data were collected from each participant twice a year for five years. The findings revealed modest, concave upward (i.e. U-shaped) trajectories for adolescent worry, intolerance of uncertainty, and fear of anxiety over the 10 assessment points. Gender differences in these trajectories were observed, with girls reporting more worry and fear of anxiety than boys across the study period. Unexpectedly, intolerance of uncertainty increased between the midpoint and endpoint of the study for girls, but not for boys. Support was found for a bidirectional and reciprocal relationship between adolescent worry and intolerance of uncertainty, with change in one partially mediating change in the other, even when controlling for depression and trait anxiety. Conversely, adolescent worry and fear of anxiety showed a predominantly unidirectional relationship, with change in worry showing a stronger mediational effect on change in fear of anxiety than vice versa, a result which remained once the variance with depression and trait anxiety was partialled out. Overall, the findings highlight the important role of cognitive processes, such as intolerance of uncertainty and fear of anxiety, in our understanding of adolescent worry. These findings have important implications for our understanding of worry during this critical period of development

Organ and tissue level properties are more sensitive to age than osteocyte lacunar characteristics in rat cortical bone

Modeling and remodeling induce significant changes of bone structure and mechanical properties with age. Therefore, it is important to gain knowledge of the processes taking place in bone over time. The rat is a widely used animal model, where much data has been accumulated on age-related changes of bone on the organ and tissue level, whereas features on the nano- and micrometer scale are much less explored. We investigated the age-related development of organ and tissue level bone properties such as bone volume, bone mineral density, and load to fracture and correlated these with osteocyte lacunar properties in rat cortical bone. Femora of 14 to 42-week-old female Wistar rats were investigated using multiple complementary techniques including X-ray micro-computed tomography and biomechanical testing. The body weight, femoral length, aBMD, load to fracture, tissue volume, bone volume, and tissue density were found to increase rapidly with age at 14-30 weeks. At the age of 30-42 weeks, the growth rate appeared to decrease. However, no accompanying changes were found in osteocyte lacunar properties such as lacunar volume, ellipsoidal radii, lacunar stretch, lacunar oblateness, or lacunar orientation with animal age. Hence, the evolution of organ and tissue level properties with age in rat cortical bone is not accompanied by related changes in osteocyte lacunar properties. This suggests that bone microstructure and bone matrix material properties and not the geometric properties of the osteocyte lacunar network are main determinants of the properties of the bone on larger length scales

Moderate-to-High Intensity Physical Exercise in Patients with Alzheimer's Disease:A Randomized Controlled Trial

Background: Studies of physical exercise in patients with Alzheimer’s disease (AD) are few and results have been inconsistent. Objective: To assess the effects of a moderate-to-high intensity aerobic exercise program in patients with mild AD. Methods: In a randomized controlled trial, we recruited 200 patients with mild AD to a supervised exercise group (60-min sessions three times a week for 16 weeks) or to a control group. Primary outcome was changed from baseline in cognitive performance estimated by Symbol Digit Modalities Test (SDMT) in the intention-to-treat (ITT) group. Secondary outcomes included changes in quality of life, ability to perform activities of daily living, and in neuropsychiatric and depressive symptoms. Results: The ITT analysis showed no significant differences between intervention and control groups in change from baseline of SDMT, other cognitive tests, quality of life, or activities of daily living. The change from baseline in Neuropsychiatric Inventory differed significantly in favor of the intervention group (mean: –3.5, 95% confidence interval (CI) –5.8 to –1.3, p = 0.002). In subjects who adhered to the protocol, we found a significant effect on change from baseline in SDMT as compared with the control group (mean: 4.2, 95% CI 0.5 to 7.9, p = 0.028), suggesting a dose-response relationship between exercise and cognition. Conclusions: This is the first randomized controlled trial with supervised moderate-to-high intensity exercise in patients with mild AD. Exercise reduced neuropsychiatric symptoms in patients with mild AD, with possible additional benefits of preserved cognition in a subgroup of patients exercising with high attendance and intensity.</jats:p

COMPLEX ARCHITECTURE OF THE OSTEOCYTE LACUNAR-CANALICULAR NETWORK IN MICE

International audienceThe osteocyte network in bone has attracted great interest due to the role of osteocytes in mechanosensing and regulation of bone remodeling. Osteocytes reside in lacunae and are interconnected by cellular processes running through a network of canaliculi; canals roughly 200 nm in diameter. The canalicular network plays a vital role in the communication between osteocytes and facilitates a way for osteocytes to orchestrate bone remodelling. Rodents are widely used as model organisms to study experimentally induced effects in bone. Human and rodent bone does, however, display large structural variations with the largest difference being the absence of harversian remodeling in rodents, which has profound implications for bone microstructure [1]. Here we have studied the lacuna-canalicular network in mouse bone to describe the communication network and the structural features found on the sub-micro meter length scale. Describing the hierarchical structure of bone demands multiscale imaging techniques [2-4] and advances in high resolution X-ray imaging has paved the way for characterization of the lacunar-canalicular network [5-7] Herein we apply X-ray holotomography with a 25 nm voxel size to mouse bone

Canalicular Junctions in the Osteocyte Lacuno-Canalicular Network of Cortical Bone

The osteocyte lacuno-canalicular network (LCN) is essential for bone remodeling because osteocytes regulate cell recruitment. This has been proposed to occur through liquid-flow-induced shear forces in the canaliculi. Models of the LCN have thus far assumed that it contains canaliculi connecting the osteocyte lacunae. However, here, we reveal that enlarged spaces occur at places where several canaliculi cross; we name these spaces canalicular junctions. We characterize them in detail within mice cortical bone using synchrotron nanotomography at two length scales, with 50 and 130 nm voxel size, and show that canalicular junctions occur at a density similar to that of osteocyte lacunae and that canalicular junctions tend to cluster. Through confocal laser scanning microscopy, we show that canalicular junctions are widespread as we have observed them in cortical bone from several species, even though the number density of the canalicular junctions was not universal. Fluid flow simulations of a simple model system with and without a canalicular junction clearly show that liquid mass transport and flow velocities are altered by the presence of canalicular junctions. We suggest that these canalicular junctions may play an important role in osteocyte communication and possibly also in canalicular fluid flow. Therefore, we believe that they constitute an important component in the bone osteocyte network

Counteracting age-related loss of skeletal muscle mass

BACKGROUND: Aging is associated with decreased muscle mass and functional capacity, which in turn decrease quality of life. The number of citizens over the age of 65 years in the Western world will increase by 50 % over the next four decades, and this demographic shift brings forth new challenges at both societal and individual levels. Only a few longitudinal studies have been reported, but whey protein supplementation seems to improve muscle mass and function, and its combination with heavy strength training appears even more effective. However, heavy resistance training may reduce adherence to training, thereby attenuating the overall benefits of training. We hypothesize that light load resistance training is more efficient when both adherence and physical improvement are considered longitudinally. We launched the interdisciplinary project on Counteracting Age-related Loss of Skeletal Muscle Mass (CALM) to investigate the impact of lifestyle changes on physical and functional outcomes as well as everyday practices and habits in a qualitative context. METHODS: We will randomize 205 participants older than 65 years to be given 1 year of two daily nutrient supplements with 10 g of sucrose and 20 g of either collagen protein, carbohydrates, or whey. Further, two groups will perform either heavy progressive resistance training or light load training on top of the whey supplement. DISCUSSION: The primary outcome of the CALM Intervention Study is the change in thigh cross-sectional area. Moreover, we will evaluate changes in physical performance, muscle fiber type and acute anabolic response to whey protein ingestion, sensory adaptation, gut microbiome, and a range of other measures, combined with questionnaires on life quality and qualitative interviews with selected subjects. The CALM Intervention Study will generate scientific evidence and recommendations to counteract age-related loss of skeletal muscle mass in elderly individuals. TRIAL REGISTRATION: ClinicalTrials.gov NCT02034760. Registered on 10 January 2014. ClinicalTrials.gov NCT02115698. Registered on 14 April 2014. Danish regional committee of the Capital Region H-4-2013-070. Registered on 4 July 2013. Danish Data Protection Agency 2012-58-0004 – BBH-2015-001 I-Suite 03432. Registered on 9 January 2015

Intolerance of uncertainty, fear of anxiety, and adolescent worry

Item does not contain fulltextA 5 year, ten wave longitudinal study of 338 adolescents assessed the association between two forms of cognitive vulnerability (intolerance of uncertainty and fear of anxiety) and worry. Multilevel mediational analyses revealed a bidirectional and reciprocal relation between intolerance of uncertainty and worry in which change in one variable partially explained change in the other. Fear of anxiety and worry also showed evidence of a bidirectional relation, although change in fear of anxiety had a much weaker mediational effect on change in worry than vice versa. The findings show that relative to fear of anxiety, intolerance of uncertainty may play a greater role in the etiology of worry in adolescents.8 p